fs/btrfs/inode.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/bio.h>
   8 #include <linux/buffer_head.h>
   9 #include <linux/file.h>
  10 #include <linux/fs.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/highmem.h>
  13 #include <linux/time.h>
  14 #include <linux/init.h>
  15 #include <linux/string.h>
  16 #include <linux/backing-dev.h>
  17 #include <linux/mpage.h>
  18 #include <linux/swap.h>
  19 #include <linux/writeback.h>
  20 #include <linux/compat.h>
  21 #include <linux/bit_spinlock.h>
  22 #include <linux/xattr.h>
  23 #include <linux/posix_acl.h>
  24 #include <linux/falloc.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/mount.h>
  28 #include <linux/btrfs.h>
  29 #include <linux/blkdev.h>
  30 #include <linux/posix_acl_xattr.h>
  31 #include <linux/uio.h>
  32 #include <linux/magic.h>
  33 #include <linux/iversion.h>
  34 #include <asm/unaligned.h>
  35 #include "ctree.h"
  36 #include "disk-io.h"
  37 #include "transaction.h"
  38 #include "btrfs_inode.h"
  39 #include "print-tree.h"
  40 #include "ordered-data.h"
  41 #include "xattr.h"
  42 #include "tree-log.h"
  43 #include "volumes.h"
  44 #include "compression.h"
  45 #include "locking.h"
  46 #include "free-space-cache.h"
  47 #include "inode-map.h"
  48 #include "backref.h"
  49 #include "props.h"
  50 #include "qgroup.h"
  51 #include "dedupe.h"
  52
  53 struct btrfs_iget_args {
  54         struct btrfs_key *location;
  55         struct btrfs_root *root;
  56 };
  57
  58 struct btrfs_dio_data {
  59         u64 reserve;
  60         u64 unsubmitted_oe_range_start;
  61         u64 unsubmitted_oe_range_end;
  62         int overwrite;
  63 };
  64
  65 static const struct inode_operations btrfs_dir_inode_operations;
  66 static const struct inode_operations btrfs_symlink_inode_operations;
  67 static const struct inode_operations btrfs_dir_ro_inode_operations;
  68 static const struct inode_operations btrfs_special_inode_operations;
  69 static const struct inode_operations btrfs_file_inode_operations;
  70 static const struct address_space_operations btrfs_aops;
  71 static const struct address_space_operations btrfs_symlink_aops;
  72 static const struct file_operations btrfs_dir_file_operations;
  73 static const struct extent_io_ops btrfs_extent_io_ops;
  74
  75 static struct kmem_cache *btrfs_inode_cachep;
  76 struct kmem_cache *btrfs_trans_handle_cachep;
  77 struct kmem_cache *btrfs_path_cachep;
  78 struct kmem_cache *btrfs_free_space_cachep;
  79
  80 #define S_SHIFT 12
  81 static const unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  82         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  83         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  84         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  85         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  86         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  87         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  88         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  89 };
  90
  91 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  92 static int btrfs_truncate(struct inode *inode, bool skip_writeback);
  93 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  94 static noinline int cow_file_range(struct inode *inode,
  95                                    struct page *locked_page,
  96                                    u64 start, u64 end, u64 delalloc_end,
  97                                    int *page_started, unsigned long *nr_written,
  98                                    int unlock, struct btrfs_dedupe_hash *hash);
  99 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
 100                                        u64 orig_start, u64 block_start,
 101                                        u64 block_len, u64 orig_block_len,
 102                                        u64 ram_bytes, int compress_type,
 103                                        int type);
 104
 105 static void __endio_write_update_ordered(struct inode *inode,
 106                                          const u64 offset, const u64 bytes,
 107                                          const bool uptodate);
 108
 109 /*
 110  * Cleanup all submitted ordered extents in specified range to handle errors
 111  * from the fill_dellaloc() callback.
 112  *
 113  * NOTE: caller must ensure that when an error happens, it can not call
 114  * extent_clear_unlock_delalloc() to clear both the bits EXTENT_DO_ACCOUNTING
 115  * and EXTENT_DELALLOC simultaneously, because that causes the reserved metadata
 116  * to be released, which we want to happen only when finishing the ordered
 117  * extent (btrfs_finish_ordered_io()). Also note that the caller of the
 118  * fill_delalloc() callback already does proper cleanup for the first page of
 119  * the range, that is, it invokes the callback writepage_end_io_hook() for the
 120  * range of the first page.
 121  */
 122 static inline void btrfs_cleanup_ordered_extents(struct inode *inode,
 123                                                  const u64 offset,
 124                                                  const u64 bytes)
 125 {
 126         unsigned long index = offset >> PAGE_SHIFT;
 127         unsigned long end_index = (offset + bytes - 1) >> PAGE_SHIFT;
 128         struct page *page;
 129
 130         while (index <= end_index) {
 131                 page = find_get_page(inode->i_mapping, index);
 132                 index++;
 133                 if (!page)
 134                         continue;
 135                 ClearPagePrivate2(page);
 136                 put_page(page);
 137         }
 138         return __endio_write_update_ordered(inode, offset + PAGE_SIZE,
 139                                             bytes - PAGE_SIZE, false);
 140 }
 141
 142 static int btrfs_dirty_inode(struct inode *inode);
 143
 144 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 145 void btrfs_test_inode_set_ops(struct inode *inode)
 146 {
 147         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 148 }
 149 #endif
 150
 151 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 152                                      struct inode *inode,  struct inode *dir,
 153                                      const struct qstr *qstr)
 154 {
 155         int err;
 156
 157         err = btrfs_init_acl(trans, inode, dir);
 158         if (!err)
 159                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 160         return err;
 161 }
 162
 163 /*
 164  * this does all the hard work for inserting an inline extent into
 165  * the btree.  The caller should have done a btrfs_drop_extents so that
 166  * no overlapping inline items exist in the btree
 167  */
 168 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 169                                 struct btrfs_path *path, int extent_inserted,
 170                                 struct btrfs_root *root, struct inode *inode,
 171                                 u64 start, size_t size, size_t compressed_size,
 172                                 int compress_type,
 173                                 struct page **compressed_pages)
 174 {
 175         struct extent_buffer *leaf;
 176         struct page *page = NULL;
 177         char *kaddr;
 178         unsigned long ptr;
 179         struct btrfs_file_extent_item *ei;
 180         int ret;
 181         size_t cur_size = size;
 182         unsigned long offset;
 183
 184         if (compressed_size && compressed_pages)
 185                 cur_size = compressed_size;
 186
 187         inode_add_bytes(inode, size);
 188
 189         if (!extent_inserted) {
 190                 struct btrfs_key key;
 191                 size_t datasize;
 192
 193                 key.objectid = btrfs_ino(BTRFS_I(inode));
 194                 key.offset = start;
 195                 key.type = BTRFS_EXTENT_DATA_KEY;
 196
 197                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 198                 path->leave_spinning = 1;
 199                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 200                                               datasize);
 201                 if (ret)
 202                         goto fail;
 203         }
 204         leaf = path->nodes[0];
 205         ei = btrfs_item_ptr(leaf, path->slots[0],
 206                             struct btrfs_file_extent_item);
 207         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 208         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 209         btrfs_set_file_extent_encryption(leaf, ei, 0);
 210         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 211         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 212         ptr = btrfs_file_extent_inline_start(ei);
 213
 214         if (compress_type != BTRFS_COMPRESS_NONE) {
 215                 struct page *cpage;
 216                 int i = 0;
 217                 while (compressed_size > 0) {
 218                         cpage = compressed_pages[i];
 219                         cur_size = min_t(unsigned long, compressed_size,
 220                                        PAGE_SIZE);
 221
 222                         kaddr = kmap_atomic(cpage);
 223                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 224                         kunmap_atomic(kaddr);
 225
 226                         i++;
 227                         ptr += cur_size;
 228                         compressed_size -= cur_size;
 229                 }
 230                 btrfs_set_file_extent_compression(leaf, ei,
 231                                                   compress_type);
 232         } else {
 233                 page = find_get_page(inode->i_mapping,
 234                                      start >> PAGE_SHIFT);
 235                 btrfs_set_file_extent_compression(leaf, ei, 0);
 236                 kaddr = kmap_atomic(page);
 237                 offset = start & (PAGE_SIZE - 1);
 238                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 239                 kunmap_atomic(kaddr);
 240                 put_page(page);
 241         }
 242         btrfs_mark_buffer_dirty(leaf);
 243         btrfs_release_path(path);
 244
 245         /*
 246          * we're an inline extent, so nobody can
 247          * extend the file past i_size without locking
 248          * a page we already have locked.
 249          *
 250          * We must do any isize and inode updates
 251          * before we unlock the pages.  Otherwise we
 252          * could end up racing with unlink.
 253          */
 254         BTRFS_I(inode)->disk_i_size = inode->i_size;
 255         ret = btrfs_update_inode(trans, root, inode);
 256
 257 fail:
 258         return ret;
 259 }
 260
 261
 262 /*
 263  * conditionally insert an inline extent into the file.  This
 264  * does the checks required to make sure the data is small enough
 265  * to fit as an inline extent.
 266  */
 267 static noinline int cow_file_range_inline(struct inode *inode, u64 start,
 268                                           u64 end, size_t compressed_size,
 269                                           int compress_type,
 270                                           struct page **compressed_pages)
 271 {
 272         struct btrfs_root *root = BTRFS_I(inode)->root;
 273         struct btrfs_fs_info *fs_info = root->fs_info;
 274         struct btrfs_trans_handle *trans;
 275         u64 isize = i_size_read(inode);
 276         u64 actual_end = min(end + 1, isize);
 277         u64 inline_len = actual_end - start;
 278         u64 aligned_end = ALIGN(end, fs_info->sectorsize);
 279         u64 data_len = inline_len;
 280         int ret;
 281         struct btrfs_path *path;
 282         int extent_inserted = 0;
 283         u32 extent_item_size;
 284
 285         if (compressed_size)
 286                 data_len = compressed_size;
 287
 288         if (start > 0 ||
 289             actual_end > fs_info->sectorsize ||
 290             data_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info) ||
 291             (!compressed_size &&
 292             (actual_end & (fs_info->sectorsize - 1)) == 0) ||
 293             end + 1 < isize ||
 294             data_len > fs_info->max_inline) {
 295                 return 1;
 296         }
 297
 298         path = btrfs_alloc_path();
 299         if (!path)
 300                 return -ENOMEM;
 301
 302         trans = btrfs_join_transaction(root);
 303         if (IS_ERR(trans)) {
 304                 btrfs_free_path(path);
 305                 return PTR_ERR(trans);
 306         }
 307         trans->block_rsv = &BTRFS_I(inode)->block_rsv;
 308
 309         if (compressed_size && compressed_pages)
 310                 extent_item_size = btrfs_file_extent_calc_inline_size(
 311                    compressed_size);
 312         else
 313                 extent_item_size = btrfs_file_extent_calc_inline_size(
 314                     inline_len);
 315
 316         ret = __btrfs_drop_extents(trans, root, inode, path,
 317                                    start, aligned_end, NULL,
 318                                    1, 1, extent_item_size, &extent_inserted);
 319         if (ret) {
 320                 btrfs_abort_transaction(trans, ret);
 321                 goto out;
 322         }
 323
 324         if (isize > actual_end)
 325                 inline_len = min_t(u64, isize, actual_end);
 326         ret = insert_inline_extent(trans, path, extent_inserted,
 327                                    root, inode, start,
 328                                    inline_len, compressed_size,
 329                                    compress_type, compressed_pages);
 330         if (ret && ret != -ENOSPC) {
 331                 btrfs_abort_transaction(trans, ret);
 332                 goto out;
 333         } else if (ret == -ENOSPC) {
 334                 ret = 1;
 335                 goto out;
 336         }
 337
 338         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 339         btrfs_drop_extent_cache(BTRFS_I(inode), start, aligned_end - 1, 0);
 340 out:
 341         /*
 342          * Don't forget to free the reserved space, as for inlined extent
 343          * it won't count as data extent, free them directly here.
 344          * And at reserve time, it's always aligned to page size, so
 345          * just free one page here.
 346          */
 347         btrfs_qgroup_free_data(inode, NULL, 0, PAGE_SIZE);
 348         btrfs_free_path(path);
 349         btrfs_end_transaction(trans);
 350         return ret;
 351 }
 352
 353 struct async_extent {
 354         u64 start;
 355         u64 ram_size;
 356         u64 compressed_size;
 357         struct page **pages;
 358         unsigned long nr_pages;
 359         int compress_type;
 360         struct list_head list;
 361 };
 362
 363 struct async_cow {
 364         struct inode *inode;
 365         struct btrfs_root *root;
 366         struct page *locked_page;
 367         u64 start;
 368         u64 end;
 369         unsigned int write_flags;
 370         struct list_head extents;
 371         struct btrfs_work work;
 372 };
 373
 374 static noinline int add_async_extent(struct async_cow *cow,
 375                                      u64 start, u64 ram_size,
 376                                      u64 compressed_size,
 377                                      struct page **pages,
 378                                      unsigned long nr_pages,
 379                                      int compress_type)
 380 {
 381         struct async_extent *async_extent;
 382
 383         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 384         BUG_ON(!async_extent); /* -ENOMEM */
 385         async_extent->start = start;
 386         async_extent->ram_size = ram_size;
 387         async_extent->compressed_size = compressed_size;
 388         async_extent->pages = pages;
 389         async_extent->nr_pages = nr_pages;
 390         async_extent->compress_type = compress_type;
 391         list_add_tail(&async_extent->list, &cow->extents);
 392         return 0;
 393 }
 394
 395 static inline int inode_need_compress(struct inode *inode, u64 start, u64 end)
 396 {
 397         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 398
 399         /* force compress */
 400         if (btrfs_test_opt(fs_info, FORCE_COMPRESS))
 401                 return 1;
 402         /* defrag ioctl */
 403         if (BTRFS_I(inode)->defrag_compress)
 404                 return 1;
 405         /* bad compression ratios */
 406         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 407                 return 0;
 408         if (btrfs_test_opt(fs_info, COMPRESS) ||
 409             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 410             BTRFS_I(inode)->prop_compress)
 411                 return btrfs_compress_heuristic(inode, start, end);
 412         return 0;
 413 }
 414
 415 static inline void inode_should_defrag(struct btrfs_inode *inode,
 416                 u64 start, u64 end, u64 num_bytes, u64 small_write)
 417 {
 418         /* If this is a small write inside eof, kick off a defrag */
 419         if (num_bytes < small_write &&
 420             (start > 0 || end + 1 < inode->disk_i_size))
 421                 btrfs_add_inode_defrag(NULL, inode);
 422 }
 423
 424 /*
 425  * we create compressed extents in two phases.  The first
 426  * phase compresses a range of pages that have already been
 427  * locked (both pages and state bits are locked).
 428  *
 429  * This is done inside an ordered work queue, and the compression
 430  * is spread across many cpus.  The actual IO submission is step
 431  * two, and the ordered work queue takes care of making sure that
 432  * happens in the same order things were put onto the queue by
 433  * writepages and friends.
 434  *
 435  * If this code finds it can't get good compression, it puts an
 436  * entry onto the work queue to write the uncompressed bytes.  This
 437  * makes sure that both compressed inodes and uncompressed inodes
 438  * are written in the same order that the flusher thread sent them
 439  * down.
 440  */
 441 static noinline void compress_file_range(struct inode *inode,
 442                                         struct page *locked_page,
 443                                         u64 start, u64 end,
 444                                         struct async_cow *async_cow,
 445                                         int *num_added)
 446 {
 447         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 448         u64 blocksize = fs_info->sectorsize;
 449         u64 actual_end;
 450         u64 isize = i_size_read(inode);
 451         int ret = 0;
 452         struct page **pages = NULL;
 453         unsigned long nr_pages;
 454         unsigned long total_compressed = 0;
 455         unsigned long total_in = 0;
 456         int i;
 457         int will_compress;
 458         int compress_type = fs_info->compress_type;
 459         int redirty = 0;
 460
 461         inode_should_defrag(BTRFS_I(inode), start, end, end - start + 1,
 462                         SZ_16K);
 463
 464         actual_end = min_t(u64, isize, end + 1);
 465 again:
 466         will_compress = 0;
 467         nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
 468         BUILD_BUG_ON((BTRFS_MAX_COMPRESSED % PAGE_SIZE) != 0);
 469         nr_pages = min_t(unsigned long, nr_pages,
 470                         BTRFS_MAX_COMPRESSED / PAGE_SIZE);
 471
 472         /*
 473          * we don't want to send crud past the end of i_size through
 474          * compression, that's just a waste of CPU time.  So, if the
 475          * end of the file is before the start of our current
 476          * requested range of bytes, we bail out to the uncompressed
 477          * cleanup code that can deal with all of this.
 478          *
 479          * It isn't really the fastest way to fix things, but this is a
 480          * very uncommon corner.
 481          */
 482         if (actual_end <= start)
 483                 goto cleanup_and_bail_uncompressed;
 484
 485         total_compressed = actual_end - start;
 486
 487         /*
 488          * skip compression for a small file range(<=blocksize) that
 489          * isn't an inline extent, since it doesn't save disk space at all.
 490          */
 491         if (total_compressed <= blocksize &&
 492            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 493                 goto cleanup_and_bail_uncompressed;
 494
 495         total_compressed = min_t(unsigned long, total_compressed,
 496                         BTRFS_MAX_UNCOMPRESSED);
 497         total_in = 0;
 498         ret = 0;
 499
 500         /*
 501          * we do compression for mount -o compress and when the
 502          * inode has not been flagged as nocompress.  This flag can
 503          * change at any time if we discover bad compression ratios.
 504          */
 505         if (inode_need_compress(inode, start, end)) {
 506                 WARN_ON(pages);
 507                 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 508                 if (!pages) {
 509                         /* just bail out to the uncompressed code */
 510                         goto cont;
 511                 }
 512
 513                 if (BTRFS_I(inode)->defrag_compress)
 514                         compress_type = BTRFS_I(inode)->defrag_compress;
 515                 else if (BTRFS_I(inode)->prop_compress)
 516                         compress_type = BTRFS_I(inode)->prop_compress;
 517
 518                 /*
 519                  * we need to call clear_page_dirty_for_io on each
 520                  * page in the range.  Otherwise applications with the file
 521                  * mmap'd can wander in and change the page contents while
 522                  * we are compressing them.
 523                  *
 524                  * If the compression fails for any reason, we set the pages
 525                  * dirty again later on.
 526                  *
 527                  * Note that the remaining part is redirtied, the start pointer
 528                  * has moved, the end is the original one.
 529                  */
 530                 if (!redirty) {
 531                         extent_range_clear_dirty_for_io(inode, start, end);
 532                         redirty = 1;
 533                 }
 534
 535                 /* Compression level is applied here and only here */
 536                 ret = btrfs_compress_pages(
 537                         compress_type | (fs_info->compress_level << 4),
 538                                            inode->i_mapping, start,
 539                                            pages,
 540                                            &nr_pages,
 541                                            &total_in,
 542                                            &total_compressed);
 543
 544                 if (!ret) {
 545                         unsigned long offset = total_compressed &
 546                                 (PAGE_SIZE - 1);
 547                         struct page *page = pages[nr_pages - 1];
 548                         char *kaddr;
 549
 550                         /* zero the tail end of the last page, we might be
 551                          * sending it down to disk
 552                          */
 553                         if (offset) {
 554                                 kaddr = kmap_atomic(page);
 555                                 memset(kaddr + offset, 0,
 556                                        PAGE_SIZE - offset);
 557                                 kunmap_atomic(kaddr);
 558                         }
 559                         will_compress = 1;
 560                 }
 561         }
 562 cont:
 563         if (start == 0) {
 564                 /* lets try to make an inline extent */
 565                 if (ret || total_in < actual_end) {
 566                         /* we didn't compress the entire range, try
 567                          * to make an uncompressed inline extent.
 568                          */
 569                         ret = cow_file_range_inline(inode, start, end, 0,
 570                                                     BTRFS_COMPRESS_NONE, NULL);
 571                 } else {
 572                         /* try making a compressed inline extent */
 573                         ret = cow_file_range_inline(inode, start, end,
 574                                                     total_compressed,
 575                                                     compress_type, pages);
 576                 }
 577                 if (ret <= 0) {
 578                         unsigned long clear_flags = EXTENT_DELALLOC |
 579                                 EXTENT_DELALLOC_NEW | EXTENT_DEFRAG |
 580                                 EXTENT_DO_ACCOUNTING;
 581                         unsigned long page_error_op;
 582
 583                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 584
 585                         /*
 586                          * inline extent creation worked or returned error,
 587                          * we don't need to create any more async work items.
 588                          * Unlock and free up our temp pages.
 589                          *
 590                          * We use DO_ACCOUNTING here because we need the
 591                          * delalloc_release_metadata to be done _after_ we drop
 592                          * our outstanding extent for clearing delalloc for this
 593                          * range.
 594                          */
 595                         extent_clear_unlock_delalloc(inode, start, end, end,
 596                                                      NULL, clear_flags,
 597                                                      PAGE_UNLOCK |
 598                                                      PAGE_CLEAR_DIRTY |
 599                                                      PAGE_SET_WRITEBACK |
 600                                                      page_error_op |
 601                                                      PAGE_END_WRITEBACK);
 602                         goto free_pages_out;
 603                 }
 604         }
 605
 606         if (will_compress) {
 607                 /*
 608                  * we aren't doing an inline extent round the compressed size
 609                  * up to a block size boundary so the allocator does sane
 610                  * things
 611                  */
 612                 total_compressed = ALIGN(total_compressed, blocksize);
 613
 614                 /*
 615                  * one last check to make sure the compression is really a
 616                  * win, compare the page count read with the blocks on disk,
 617                  * compression must free at least one sector size
 618                  */
 619                 total_in = ALIGN(total_in, PAGE_SIZE);
 620                 if (total_compressed + blocksize <= total_in) {
 621                         *num_added += 1;
 622
 623                         /*
 624                          * The async work queues will take care of doing actual
 625                          * allocation on disk for these compressed pages, and
 626                          * will submit them to the elevator.
 627                          */
 628                         add_async_extent(async_cow, start, total_in,
 629                                         total_compressed, pages, nr_pages,
 630                                         compress_type);
 631
 632                         if (start + total_in < end) {
 633                                 start += total_in;
 634                                 pages = NULL;
 635                                 cond_resched();
 636                                 goto again;
 637                         }
 638                         return;
 639                 }
 640         }
 641         if (pages) {
 642                 /*
 643                  * the compression code ran but failed to make things smaller,
 644                  * free any pages it allocated and our page pointer array
 645                  */
 646                 for (i = 0; i < nr_pages; i++) {
 647                         WARN_ON(pages[i]->mapping);
 648                         put_page(pages[i]);
 649                 }
 650                 kfree(pages);
 651                 pages = NULL;
 652                 total_compressed = 0;
 653                 nr_pages = 0;
 654
 655                 /* flag the file so we don't compress in the future */
 656                 if (!btrfs_test_opt(fs_info, FORCE_COMPRESS) &&
 657                     !(BTRFS_I(inode)->prop_compress)) {
 658                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 659                 }
 660         }
 661 cleanup_and_bail_uncompressed:
 662         /*
 663          * No compression, but we still need to write the pages in the file
 664          * we've been given so far.  redirty the locked page if it corresponds
 665          * to our extent and set things up for the async work queue to run
 666          * cow_file_range to do the normal delalloc dance.
 667          */
 668         if (page_offset(locked_page) >= start &&
 669             page_offset(locked_page) <= end)
 670                 __set_page_dirty_nobuffers(locked_page);
 671                 /* unlocked later on in the async handlers */
 672
 673         if (redirty)
 674                 extent_range_redirty_for_io(inode, start, end);
 675         add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0,
 676                          BTRFS_COMPRESS_NONE);
 677         *num_added += 1;
 678
 679         return;
 680
 681 free_pages_out:
 682         for (i = 0; i < nr_pages; i++) {
 683                 WARN_ON(pages[i]->mapping);
 684                 put_page(pages[i]);
 685         }
 686         kfree(pages);
 687 }
 688
 689 static void free_async_extent_pages(struct async_extent *async_extent)
 690 {
 691         int i;
 692
 693         if (!async_extent->pages)
 694                 return;
 695
 696         for (i = 0; i < async_extent->nr_pages; i++) {
 697                 WARN_ON(async_extent->pages[i]->mapping);
 698                 put_page(async_extent->pages[i]);
 699         }
 700         kfree(async_extent->pages);
 701         async_extent->nr_pages = 0;
 702         async_extent->pages = NULL;
 703 }
 704
 705 /*
 706  * phase two of compressed writeback.  This is the ordered portion
 707  * of the code, which only gets called in the order the work was
 708  * queued.  We walk all the async extents created by compress_file_range
 709  * and send them down to the disk.
 710  */
 711 static noinline void submit_compressed_extents(struct inode *inode,
 712                                               struct async_cow *async_cow)
 713 {
 714         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 715         struct async_extent *async_extent;
 716         u64 alloc_hint = 0;
 717         struct btrfs_key ins;
 718         struct extent_map *em;
 719         struct btrfs_root *root = BTRFS_I(inode)->root;
 720         struct extent_io_tree *io_tree;
 721         int ret = 0;
 722
 723 again:
 724         while (!list_empty(&async_cow->extents)) {
 725                 async_extent = list_entry(async_cow->extents.next,
 726                                           struct async_extent, list);
 727                 list_del(&async_extent->list);
 728
 729                 io_tree = &BTRFS_I(inode)->io_tree;
 730
 731 retry:
 732                 /* did the compression code fall back to uncompressed IO? */
 733                 if (!async_extent->pages) {
 734                         int page_started = 0;
 735                         unsigned long nr_written = 0;
 736
 737                         lock_extent(io_tree, async_extent->start,
 738                                          async_extent->start +
 739                                          async_extent->ram_size - 1);
 740
 741                         /* allocate blocks */
 742                         ret = cow_file_range(inode, async_cow->locked_page,
 743                                              async_extent->start,
 744                                              async_extent->start +
 745                                              async_extent->ram_size - 1,
 746                                              async_extent->start +
 747                                              async_extent->ram_size - 1,
 748                                              &page_started, &nr_written, 0,
 749                                              NULL);
 750
 751                         /* JDM XXX */
 752
 753                         /*
 754                          * if page_started, cow_file_range inserted an
 755                          * inline extent and took care of all the unlocking
 756                          * and IO for us.  Otherwise, we need to submit
 757                          * all those pages down to the drive.
 758                          */
 759                         if (!page_started && !ret)
 760                                 extent_write_locked_range(inode,
 761                                                   async_extent->start,
 762                                                   async_extent->start +
 763                                                   async_extent->ram_size - 1,
 764                                                   WB_SYNC_ALL);
 765                         else if (ret)
 766                                 unlock_page(async_cow->locked_page);
 767                         kfree(async_extent);
 768                         cond_resched();
 769                         continue;
 770                 }
 771
 772                 lock_extent(io_tree, async_extent->start,
 773                             async_extent->start + async_extent->ram_size - 1);
 774
 775                 ret = btrfs_reserve_extent(root, async_extent->ram_size,
 776                                            async_extent->compressed_size,
 777                                            async_extent->compressed_size,
 778                                            0, alloc_hint, &ins, 1, 1);
 779                 if (ret) {
 780                         free_async_extent_pages(async_extent);
 781
 782                         if (ret == -ENOSPC) {
 783                                 unlock_extent(io_tree, async_extent->start,
 784                                               async_extent->start +
 785                                               async_extent->ram_size - 1);
 786
 787                                 /*
 788                                  * we need to redirty the pages if we decide to
 789                                  * fallback to uncompressed IO, otherwise we
 790                                  * will not submit these pages down to lower
 791                                  * layers.
 792                                  */
 793                                 extent_range_redirty_for_io(inode,
 794                                                 async_extent->start,
 795                                                 async_extent->start +
 796                                                 async_extent->ram_size - 1);
 797
 798                                 goto retry;
 799                         }
 800                         goto out_free;
 801                 }
 802                 /*
 803                  * here we're doing allocation and writeback of the
 804                  * compressed pages
 805                  */
 806                 em = create_io_em(inode, async_extent->start,
 807                                   async_extent->ram_size, /* len */
 808                                   async_extent->start, /* orig_start */
 809                                   ins.objectid, /* block_start */
 810                                   ins.offset, /* block_len */
 811                                   ins.offset, /* orig_block_len */
 812                                   async_extent->ram_size, /* ram_bytes */
 813                                   async_extent->compress_type,
 814                                   BTRFS_ORDERED_COMPRESSED);
 815                 if (IS_ERR(em))
 816                         /* ret value is not necessary due to void function */
 817                         goto out_free_reserve;
 818                 free_extent_map(em);
 819
 820                 ret = btrfs_add_ordered_extent_compress(inode,
 821                                                 async_extent->start,
 822                                                 ins.objectid,
 823                                                 async_extent->ram_size,
 824                                                 ins.offset,
 825                                                 BTRFS_ORDERED_COMPRESSED,
 826                                                 async_extent->compress_type);
 827                 if (ret) {
 828                         btrfs_drop_extent_cache(BTRFS_I(inode),
 829                                                 async_extent->start,
 830                                                 async_extent->start +
 831                                                 async_extent->ram_size - 1, 0);
 832                         goto out_free_reserve;
 833                 }
 834                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 835
 836                 /*
 837                  * clear dirty, set writeback and unlock the pages.
 838                  */
 839                 extent_clear_unlock_delalloc(inode, async_extent->start,
 840                                 async_extent->start +
 841                                 async_extent->ram_size - 1,
 842                                 async_extent->start +
 843                                 async_extent->ram_size - 1,
 844                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 845                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 846                                 PAGE_SET_WRITEBACK);
 847                 if (btrfs_submit_compressed_write(inode,
 848                                     async_extent->start,
 849                                     async_extent->ram_size,
 850                                     ins.objectid,
 851                                     ins.offset, async_extent->pages,
 852                                     async_extent->nr_pages,
 853                                     async_cow->write_flags)) {
 854                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 855                         struct page *p = async_extent->pages[0];
 856                         const u64 start = async_extent->start;
 857                         const u64 end = start + async_extent->ram_size - 1;
 858
 859                         p->mapping = inode->i_mapping;
 860                         tree->ops->writepage_end_io_hook(p, start, end,
 861                                                          NULL, 0);
 862                         p->mapping = NULL;
 863                         extent_clear_unlock_delalloc(inode, start, end, end,
 864                                                      NULL, 0,
 865                                                      PAGE_END_WRITEBACK |
 866                                                      PAGE_SET_ERROR);
 867                         free_async_extent_pages(async_extent);
 868                 }
 869                 alloc_hint = ins.objectid + ins.offset;
 870                 kfree(async_extent);
 871                 cond_resched();
 872         }
 873         return;
 874 out_free_reserve:
 875         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 876         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
 877 out_free:
 878         extent_clear_unlock_delalloc(inode, async_extent->start,
 879                                      async_extent->start +
 880                                      async_extent->ram_size - 1,
 881                                      async_extent->start +
 882                                      async_extent->ram_size - 1,
 883                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 884                                      EXTENT_DELALLOC_NEW |
 885                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 886                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 887                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 888                                      PAGE_SET_ERROR);
 889         free_async_extent_pages(async_extent);
 890         kfree(async_extent);
 891         goto again;
 892 }
 893
 894 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 895                                       u64 num_bytes)
 896 {
 897         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 898         struct extent_map *em;
 899         u64 alloc_hint = 0;
 900
 901         read_lock(&em_tree->lock);
 902         em = search_extent_mapping(em_tree, start, num_bytes);
 903         if (em) {
 904                 /*
 905                  * if block start isn't an actual block number then find the
 906                  * first block in this inode and use that as a hint.  If that
 907                  * block is also bogus then just don't worry about it.
 908                  */
 909                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 910                         free_extent_map(em);
 911                         em = search_extent_mapping(em_tree, 0, 0);
 912                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 913                                 alloc_hint = em->block_start;
 914                         if (em)
 915                                 free_extent_map(em);
 916                 } else {
 917                         alloc_hint = em->block_start;
 918                         free_extent_map(em);
 919                 }
 920         }
 921         read_unlock(&em_tree->lock);
 922
 923         return alloc_hint;
 924 }
 925
 926 /*
 927  * when extent_io.c finds a delayed allocation range in the file,
 928  * the call backs end up in this code.  The basic idea is to
 929  * allocate extents on disk for the range, and create ordered data structs
 930  * in ram to track those extents.
 931  *
 932  * locked_page is the page that writepage had locked already.  We use
 933  * it to make sure we don't do extra locks or unlocks.
 934  *
 935  * *page_started is set to one if we unlock locked_page and do everything
 936  * required to start IO on it.  It may be clean and already done with
 937  * IO when we return.
 938  */
 939 static noinline int cow_file_range(struct inode *inode,
 940                                    struct page *locked_page,
 941                                    u64 start, u64 end, u64 delalloc_end,
 942                                    int *page_started, unsigned long *nr_written,
 943                                    int unlock, struct btrfs_dedupe_hash *hash)
 944 {
 945         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 946         struct btrfs_root *root = BTRFS_I(inode)->root;
 947         u64 alloc_hint = 0;
 948         u64 num_bytes;
 949         unsigned long ram_size;
 950         u64 cur_alloc_size = 0;
 951         u64 blocksize = fs_info->sectorsize;
 952         struct btrfs_key ins;
 953         struct extent_map *em;
 954         unsigned clear_bits;
 955         unsigned long page_ops;
 956         bool extent_reserved = false;
 957         int ret = 0;
 958
 959         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
 960                 WARN_ON_ONCE(1);
 961                 ret = -EINVAL;
 962                 goto out_unlock;
 963         }
 964
 965         num_bytes = ALIGN(end - start + 1, blocksize);
 966         num_bytes = max(blocksize,  num_bytes);
 967         ASSERT(num_bytes <= btrfs_super_total_bytes(fs_info->super_copy));
 968
 969         inode_should_defrag(BTRFS_I(inode), start, end, num_bytes, SZ_64K);
 970
 971         if (start == 0) {
 972                 /* lets try to make an inline extent */
 973                 ret = cow_file_range_inline(inode, start, end, 0,
 974                                             BTRFS_COMPRESS_NONE, NULL);
 975                 if (ret == 0) {
 976                         /*
 977                          * We use DO_ACCOUNTING here because we need the
 978                          * delalloc_release_metadata to be run _after_ we drop
 979                          * our outstanding extent for clearing delalloc for this
 980                          * range.
 981                          */
 982                         extent_clear_unlock_delalloc(inode, start, end,
 983                                      delalloc_end, NULL,
 984                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 985                                      EXTENT_DELALLOC_NEW | EXTENT_DEFRAG |
 986                                      EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
 987                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 988                                      PAGE_END_WRITEBACK);
 989                         *nr_written = *nr_written +
 990                              (end - start + PAGE_SIZE) / PAGE_SIZE;
 991                         *page_started = 1;
 992                         goto out;
 993                 } else if (ret < 0) {
 994                         goto out_unlock;
 995                 }
 996         }
 997
 998         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 999         btrfs_drop_extent_cache(BTRFS_I(inode), start,
1000                         start + num_bytes - 1, 0);
1001
1002         while (num_bytes > 0) {
1003                 cur_alloc_size = num_bytes;
1004                 ret = btrfs_reserve_extent(root, cur_alloc_size, cur_alloc_size,
1005                                            fs_info->sectorsize, 0, alloc_hint,
1006                                            &ins, 1, 1);
1007                 if (ret < 0)
1008                         goto out_unlock;
1009                 cur_alloc_size = ins.offset;
1010                 extent_reserved = true;
1011
1012                 ram_size = ins.offset;
1013                 em = create_io_em(inode, start, ins.offset, /* len */
1014                                   start, /* orig_start */
1015                                   ins.objectid, /* block_start */
1016                                   ins.offset, /* block_len */
1017                                   ins.offset, /* orig_block_len */
1018                                   ram_size, /* ram_bytes */
1019                                   BTRFS_COMPRESS_NONE, /* compress_type */
1020                                   BTRFS_ORDERED_REGULAR /* type */);
1021                 if (IS_ERR(em)) {
1022                         ret = PTR_ERR(em);
1023                         goto out_reserve;
1024                 }
1025                 free_extent_map(em);
1026
1027                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1028                                                ram_size, cur_alloc_size, 0);
1029                 if (ret)
1030                         goto out_drop_extent_cache;
1031
1032                 if (root->root_key.objectid ==
1033                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1034                         ret = btrfs_reloc_clone_csums(inode, start,
1035                                                       cur_alloc_size);
1036                         /*
1037                          * Only drop cache here, and process as normal.
1038                          *
1039                          * We must not allow extent_clear_unlock_delalloc()
1040                          * at out_unlock label to free meta of this ordered
1041                          * extent, as its meta should be freed by
1042                          * btrfs_finish_ordered_io().
1043                          *
1044                          * So we must continue until @start is increased to
1045                          * skip current ordered extent.
1046                          */
1047                         if (ret)
1048                                 btrfs_drop_extent_cache(BTRFS_I(inode), start,
1049                                                 start + ram_size - 1, 0);
1050                 }
1051
1052                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1053
1054                 /* we're not doing compressed IO, don't unlock the first
1055                  * page (which the caller expects to stay locked), don't
1056                  * clear any dirty bits and don't set any writeback bits
1057                  *
1058                  * Do set the Private2 bit so we know this page was properly
1059                  * setup for writepage
1060                  */
1061                 page_ops = unlock ? PAGE_UNLOCK : 0;
1062                 page_ops |= PAGE_SET_PRIVATE2;
1063
1064                 extent_clear_unlock_delalloc(inode, start,
1065                                              start + ram_size - 1,
1066                                              delalloc_end, locked_page,
1067                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1068                                              page_ops);
1069                 if (num_bytes < cur_alloc_size)
1070                         num_bytes = 0;
1071                 else
1072                         num_bytes -= cur_alloc_size;
1073                 alloc_hint = ins.objectid + ins.offset;
1074                 start += cur_alloc_size;
1075                 extent_reserved = false;
1076
1077                 /*
1078                  * btrfs_reloc_clone_csums() error, since start is increased
1079                  * extent_clear_unlock_delalloc() at out_unlock label won't
1080                  * free metadata of current ordered extent, we're OK to exit.
1081                  */
1082                 if (ret)
1083                         goto out_unlock;
1084         }
1085 out:
1086         return ret;
1087
1088 out_drop_extent_cache:
1089         btrfs_drop_extent_cache(BTRFS_I(inode), start, start + ram_size - 1, 0);
1090 out_reserve:
1091         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1092         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
1093 out_unlock:
1094         clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
1095                 EXTENT_DEFRAG | EXTENT_CLEAR_META_RESV;
1096         page_ops = PAGE_UNLOCK | PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
1097                 PAGE_END_WRITEBACK;
1098         /*
1099          * If we reserved an extent for our delalloc range (or a subrange) and
1100          * failed to create the respective ordered extent, then it means that
1101          * when we reserved the extent we decremented the extent's size from
1102          * the data space_info's bytes_may_use counter and incremented the
1103          * space_info's bytes_reserved counter by the same amount. We must make
1104          * sure extent_clear_unlock_delalloc() does not try to decrement again
1105          * the data space_info's bytes_may_use counter, therefore we do not pass
1106          * it the flag EXTENT_CLEAR_DATA_RESV.
1107          */
1108         if (extent_reserved) {
1109                 extent_clear_unlock_delalloc(inode, start,
1110                                              start + cur_alloc_size,
1111                                              start + cur_alloc_size,
1112                                              locked_page,
1113                                              clear_bits,
1114                                              page_ops);
1115                 start += cur_alloc_size;
1116                 if (start >= end)
1117                         goto out;
1118         }
1119         extent_clear_unlock_delalloc(inode, start, end, delalloc_end,
1120                                      locked_page,
1121                                      clear_bits | EXTENT_CLEAR_DATA_RESV,
1122                                      page_ops);
1123         goto out;
1124 }
1125
1126 /*
1127  * work queue call back to started compression on a file and pages
1128  */
1129 static noinline void async_cow_start(struct btrfs_work *work)
1130 {
1131         struct async_cow *async_cow;
1132         int num_added = 0;
1133         async_cow = container_of(work, struct async_cow, work);
1134
1135         compress_file_range(async_cow->inode, async_cow->locked_page,
1136                             async_cow->start, async_cow->end, async_cow,
1137                             &num_added);
1138         if (num_added == 0) {
1139                 btrfs_add_delayed_iput(async_cow->inode);
1140                 async_cow->inode = NULL;
1141         }
1142 }
1143
1144 /*
1145  * work queue call back to submit previously compressed pages
1146  */
1147 static noinline void async_cow_submit(struct btrfs_work *work)
1148 {
1149         struct btrfs_fs_info *fs_info;
1150         struct async_cow *async_cow;
1151         struct btrfs_root *root;
1152         unsigned long nr_pages;
1153
1154         async_cow = container_of(work, struct async_cow, work);
1155
1156         root = async_cow->root;
1157         fs_info = root->fs_info;
1158         nr_pages = (async_cow->end - async_cow->start + PAGE_SIZE) >>
1159                 PAGE_SHIFT;
1160
1161         /* atomic_sub_return implies a barrier */
1162         if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) <
1163             5 * SZ_1M)
1164                 cond_wake_up_nomb(&fs_info->async_submit_wait);
1165
1166         if (async_cow->inode)
1167                 submit_compressed_extents(async_cow->inode, async_cow);
1168 }
1169
1170 static noinline void async_cow_free(struct btrfs_work *work)
1171 {
1172         struct async_cow *async_cow;
1173         async_cow = container_of(work, struct async_cow, work);
1174         if (async_cow->inode)
1175                 btrfs_add_delayed_iput(async_cow->inode);
1176         kfree(async_cow);
1177 }
1178
1179 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1180                                 u64 start, u64 end, int *page_started,
1181                                 unsigned long *nr_written,
1182                                 unsigned int write_flags)
1183 {
1184         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1185         struct async_cow *async_cow;
1186         struct btrfs_root *root = BTRFS_I(inode)->root;
1187         unsigned long nr_pages;
1188         u64 cur_end;
1189
1190         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1191                          1, 0, NULL);
1192         while (start < end) {
1193                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1194                 BUG_ON(!async_cow); /* -ENOMEM */
1195                 async_cow->inode = igrab(inode);
1196                 async_cow->root = root;
1197                 async_cow->locked_page = locked_page;
1198                 async_cow->start = start;
1199                 async_cow->write_flags = write_flags;
1200
1201                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1202                     !btrfs_test_opt(fs_info, FORCE_COMPRESS))
1203                         cur_end = end;
1204                 else
1205                         cur_end = min(end, start + SZ_512K - 1);
1206
1207                 async_cow->end = cur_end;
1208                 INIT_LIST_HEAD(&async_cow->extents);
1209
1210                 btrfs_init_work(&async_cow->work,
1211                                 btrfs_delalloc_helper,
1212                                 async_cow_start, async_cow_submit,
1213                                 async_cow_free);
1214
1215                 nr_pages = (cur_end - start + PAGE_SIZE) >>
1216                         PAGE_SHIFT;
1217                 atomic_add(nr_pages, &fs_info->async_delalloc_pages);
1218
1219                 btrfs_queue_work(fs_info->delalloc_workers, &async_cow->work);
1220
1221                 *nr_written += nr_pages;
1222                 start = cur_end + 1;
1223         }
1224         *page_started = 1;
1225         return 0;
1226 }
1227
1228 static noinline int csum_exist_in_range(struct btrfs_fs_info *fs_info,
1229                                         u64 bytenr, u64 num_bytes)
1230 {
1231         int ret;
1232         struct btrfs_ordered_sum *sums;
1233         LIST_HEAD(list);
1234
1235         ret = btrfs_lookup_csums_range(fs_info->csum_root, bytenr,
1236                                        bytenr + num_bytes - 1, &list, 0);
1237         if (ret == 0 && list_empty(&list))
1238                 return 0;
1239
1240         while (!list_empty(&list)) {
1241                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1242                 list_del(&sums->list);
1243                 kfree(sums);
1244         }
1245         if (ret < 0)
1246                 return ret;
1247         return 1;
1248 }
1249
1250 /*
1251  * when nowcow writeback call back.  This checks for snapshots or COW copies
1252  * of the extents that exist in the file, and COWs the file as required.
1253  *
1254  * If no cow copies or snapshots exist, we write directly to the existing
1255  * blocks on disk
1256  */
1257 static noinline int run_delalloc_nocow(struct inode *inode,
1258                                        struct page *locked_page,
1259                               u64 start, u64 end, int *page_started, int force,
1260                               unsigned long *nr_written)
1261 {
1262         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1263         struct btrfs_root *root = BTRFS_I(inode)->root;
1264         struct extent_buffer *leaf;
1265         struct btrfs_path *path;
1266         struct btrfs_file_extent_item *fi;
1267         struct btrfs_key found_key;
1268         struct extent_map *em;
1269         u64 cow_start;
1270         u64 cur_offset;
1271         u64 extent_end;
1272         u64 extent_offset;
1273         u64 disk_bytenr;
1274         u64 num_bytes;
1275         u64 disk_num_bytes;
1276         u64 ram_bytes;
1277         int extent_type;
1278         int ret, err;
1279         int type;
1280         int nocow;
1281         int check_prev = 1;
1282         bool nolock;
1283         u64 ino = btrfs_ino(BTRFS_I(inode));
1284
1285         path = btrfs_alloc_path();
1286         if (!path) {
1287                 extent_clear_unlock_delalloc(inode, start, end, end,
1288                                              locked_page,
1289                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1290                                              EXTENT_DO_ACCOUNTING |
1291                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1292                                              PAGE_CLEAR_DIRTY |
1293                                              PAGE_SET_WRITEBACK |
1294                                              PAGE_END_WRITEBACK);
1295                 return -ENOMEM;
1296         }
1297
1298         nolock = btrfs_is_free_space_inode(BTRFS_I(inode));
1299
1300         cow_start = (u64)-1;
1301         cur_offset = start;
1302         while (1) {
1303                 ret = btrfs_lookup_file_extent(NULL, root, path, ino,
1304                                                cur_offset, 0);
1305                 if (ret < 0)
1306                         goto error;
1307                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1308                         leaf = path->nodes[0];
1309                         btrfs_item_key_to_cpu(leaf, &found_key,
1310                                               path->slots[0] - 1);
1311                         if (found_key.objectid == ino &&
1312                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1313                                 path->slots[0]--;
1314                 }
1315                 check_prev = 0;
1316 next_slot:
1317                 leaf = path->nodes[0];
1318                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1319                         ret = btrfs_next_leaf(root, path);
1320                         if (ret < 0) {
1321                                 if (cow_start != (u64)-1)
1322                                         cur_offset = cow_start;
1323                                 goto error;
1324                         }
1325                         if (ret > 0)
1326                                 break;
1327                         leaf = path->nodes[0];
1328                 }
1329
1330                 nocow = 0;
1331                 disk_bytenr = 0;
1332                 num_bytes = 0;
1333                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1334
1335                 if (found_key.objectid > ino)
1336                         break;
1337                 if (WARN_ON_ONCE(found_key.objectid < ino) ||
1338                     found_key.type < BTRFS_EXTENT_DATA_KEY) {
1339                         path->slots[0]++;
1340                         goto next_slot;
1341                 }
1342                 if (found_key.type > BTRFS_EXTENT_DATA_KEY ||
1343                     found_key.offset > end)
1344                         break;
1345
1346                 if (found_key.offset > cur_offset) {
1347                         extent_end = found_key.offset;
1348                         extent_type = 0;
1349                         goto out_check;
1350                 }
1351
1352                 fi = btrfs_item_ptr(leaf, path->slots[0],
1353                                     struct btrfs_file_extent_item);
1354                 extent_type = btrfs_file_extent_type(leaf, fi);
1355
1356                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1357                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1358                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1359                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1360                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1361                         extent_end = found_key.offset +
1362                                 btrfs_file_extent_num_bytes(leaf, fi);
1363                         disk_num_bytes =
1364                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1365                         if (extent_end <= start) {
1366                                 path->slots[0]++;
1367                                 goto next_slot;
1368                         }
1369                         if (disk_bytenr == 0)
1370                                 goto out_check;
1371                         if (btrfs_file_extent_compression(leaf, fi) ||
1372                             btrfs_file_extent_encryption(leaf, fi) ||
1373                             btrfs_file_extent_other_encoding(leaf, fi))
1374                                 goto out_check;
1375                         /*
1376                          * Do the same check as in btrfs_cross_ref_exist but
1377                          * without the unnecessary search.
1378                          */
1379                         if (btrfs_file_extent_generation(leaf, fi) <=
1380                             btrfs_root_last_snapshot(&root->root_item))
1381                                 goto out_check;
1382                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1383                                 goto out_check;
1384                         if (btrfs_extent_readonly(fs_info, disk_bytenr))
1385                                 goto out_check;
1386                         ret = btrfs_cross_ref_exist(root, ino,
1387                                                     found_key.offset -
1388                                                     extent_offset, disk_bytenr);
1389                         if (ret) {
1390                                 /*
1391                                  * ret could be -EIO if the above fails to read
1392                                  * metadata.
1393                                  */
1394                                 if (ret < 0) {
1395                                         if (cow_start != (u64)-1)
1396                                                 cur_offset = cow_start;
1397                                         goto error;
1398                                 }
1399
1400                                 WARN_ON_ONCE(nolock);
1401                                 goto out_check;
1402                         }
1403                         disk_bytenr += extent_offset;
1404                         disk_bytenr += cur_offset - found_key.offset;
1405                         num_bytes = min(end + 1, extent_end) - cur_offset;
1406                         /*
1407                          * if there are pending snapshots for this root,
1408                          * we fall into common COW way.
1409                          */
1410                         if (!nolock) {
1411                                 err = btrfs_start_write_no_snapshotting(root);
1412                                 if (!err)
1413                                         goto out_check;
1414                         }
1415                         /*
1416                          * force cow if csum exists in the range.
1417                          * this ensure that csum for a given extent are
1418                          * either valid or do not exist.
1419                          */
1420                         ret = csum_exist_in_range(fs_info, disk_bytenr,
1421                                                   num_bytes);
1422                         if (ret) {
1423                                 if (!nolock)
1424                                         btrfs_end_write_no_snapshotting(root);
1425
1426                                 /*
1427                                  * ret could be -EIO if the above fails to read
1428                                  * metadata.
1429                                  */
1430                                 if (ret < 0) {
1431                                         if (cow_start != (u64)-1)
1432                                                 cur_offset = cow_start;
1433                                         goto error;
1434                                 }
1435                                 WARN_ON_ONCE(nolock);
1436                                 goto out_check;
1437                         }
1438                         if (!btrfs_inc_nocow_writers(fs_info, disk_bytenr)) {
1439                                 if (!nolock)
1440                                         btrfs_end_write_no_snapshotting(root);
1441                                 goto out_check;
1442                         }
1443                         nocow = 1;
1444                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1445                         extent_end = found_key.offset +
1446                                 btrfs_file_extent_inline_len(leaf,
1447                                                      path->slots[0], fi);
1448                         extent_end = ALIGN(extent_end,
1449                                            fs_info->sectorsize);
1450                 } else {
1451                         BUG_ON(1);
1452                 }
1453 out_check:
1454                 if (extent_end <= start) {
1455                         path->slots[0]++;
1456                         if (!nolock && nocow)
1457                                 btrfs_end_write_no_snapshotting(root);
1458                         if (nocow)
1459                                 btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1460                         goto next_slot;
1461                 }
1462                 if (!nocow) {
1463                         if (cow_start == (u64)-1)
1464                                 cow_start = cur_offset;
1465                         cur_offset = extent_end;
1466                         if (cur_offset > end)
1467                                 break;
1468                         path->slots[0]++;
1469                         goto next_slot;
1470                 }
1471
1472                 btrfs_release_path(path);
1473                 if (cow_start != (u64)-1) {
1474                         ret = cow_file_range(inode, locked_page,
1475                                              cow_start, found_key.offset - 1,
1476                                              end, page_started, nr_written, 1,
1477                                              NULL);
1478                         if (ret) {
1479                                 if (!nolock && nocow)
1480                                         btrfs_end_write_no_snapshotting(root);
1481                                 if (nocow)
1482                                         btrfs_dec_nocow_writers(fs_info,
1483                                                                 disk_bytenr);
1484                                 goto error;
1485                         }
1486                         cow_start = (u64)-1;
1487                 }
1488
1489                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1490                         u64 orig_start = found_key.offset - extent_offset;
1491
1492                         em = create_io_em(inode, cur_offset, num_bytes,
1493                                           orig_start,
1494                                           disk_bytenr, /* block_start */
1495                                           num_bytes, /* block_len */
1496                                           disk_num_bytes, /* orig_block_len */
1497                                           ram_bytes, BTRFS_COMPRESS_NONE,
1498                                           BTRFS_ORDERED_PREALLOC);
1499                         if (IS_ERR(em)) {
1500                                 if (!nolock && nocow)
1501                                         btrfs_end_write_no_snapshotting(root);
1502                                 if (nocow)
1503                                         btrfs_dec_nocow_writers(fs_info,
1504                                                                 disk_bytenr);
1505                                 ret = PTR_ERR(em);
1506                                 goto error;
1507                         }
1508                         free_extent_map(em);
1509                 }
1510
1511                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1512                         type = BTRFS_ORDERED_PREALLOC;
1513                 } else {
1514                         type = BTRFS_ORDERED_NOCOW;
1515                 }
1516
1517                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1518                                                num_bytes, num_bytes, type);
1519                 if (nocow)
1520                         btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1521                 BUG_ON(ret); /* -ENOMEM */
1522
1523                 if (root->root_key.objectid ==
1524                     BTRFS_DATA_RELOC_TREE_OBJECTID)
1525                         /*
1526                          * Error handled later, as we must prevent
1527                          * extent_clear_unlock_delalloc() in error handler
1528                          * from freeing metadata of created ordered extent.
1529                          */
1530                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1531                                                       num_bytes);
1532
1533                 extent_clear_unlock_delalloc(inode, cur_offset,
1534                                              cur_offset + num_bytes - 1, end,
1535                                              locked_page, EXTENT_LOCKED |
1536                                              EXTENT_DELALLOC |
1537                                              EXTENT_CLEAR_DATA_RESV,
1538                                              PAGE_UNLOCK | PAGE_SET_PRIVATE2);
1539
1540                 if (!nolock && nocow)
1541                         btrfs_end_write_no_snapshotting(root);
1542                 cur_offset = extent_end;
1543
1544                 /*
1545                  * btrfs_reloc_clone_csums() error, now we're OK to call error
1546                  * handler, as metadata for created ordered extent will only
1547                  * be freed by btrfs_finish_ordered_io().
1548                  */
1549                 if (ret)
1550                         goto error;
1551                 if (cur_offset > end)
1552                         break;
1553         }
1554         btrfs_release_path(path);
1555
1556         if (cur_offset <= end && cow_start == (u64)-1) {
1557                 cow_start = cur_offset;
1558                 cur_offset = end;
1559         }
1560
1561         if (cow_start != (u64)-1) {
1562                 ret = cow_file_range(inode, locked_page, cow_start, end, end,
1563                                      page_started, nr_written, 1, NULL);
1564                 if (ret)
1565                         goto error;
1566         }
1567
1568 error:
1569         if (ret && cur_offset < end)
1570                 extent_clear_unlock_delalloc(inode, cur_offset, end, end,
1571                                              locked_page, EXTENT_LOCKED |
1572                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1573                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1574                                              PAGE_CLEAR_DIRTY |
1575                                              PAGE_SET_WRITEBACK |
1576                                              PAGE_END_WRITEBACK);
1577         btrfs_free_path(path);
1578         return ret;
1579 }
1580
1581 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1582 {
1583
1584         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1585             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1586                 return 0;
1587
1588         /*
1589          * @defrag_bytes is a hint value, no spinlock held here,
1590          * if is not zero, it means the file is defragging.
1591          * Force cow if given extent needs to be defragged.
1592          */
1593         if (BTRFS_I(inode)->defrag_bytes &&
1594             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1595                            EXTENT_DEFRAG, 0, NULL))
1596                 return 1;
1597
1598         return 0;
1599 }
1600
1601 /*
1602  * extent_io.c call back to do delayed allocation processing
1603  */
1604 static int run_delalloc_range(void *private_data, struct page *locked_page,
1605                               u64 start, u64 end, int *page_started,
1606                               unsigned long *nr_written,
1607                               struct writeback_control *wbc)
1608 {
1609         struct inode *inode = private_data;
1610         int ret;
1611         int force_cow = need_force_cow(inode, start, end);
1612         unsigned int write_flags = wbc_to_write_flags(wbc);
1613
1614         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1615                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1616                                          page_started, 1, nr_written);
1617         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1618                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1619                                          page_started, 0, nr_written);
1620         } else if (!inode_need_compress(inode, start, end)) {
1621                 ret = cow_file_range(inode, locked_page, start, end, end,
1622                                       page_started, nr_written, 1, NULL);
1623         } else {
1624                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1625                         &BTRFS_I(inode)->runtime_flags);
1626                 ret = cow_file_range_async(inode, locked_page, start, end,
1627                                            page_started, nr_written,
1628                                            write_flags);
1629         }
1630         if (ret)
1631                 btrfs_cleanup_ordered_extents(inode, start, end - start + 1);
1632         return ret;
1633 }
1634
1635 static void btrfs_split_extent_hook(void *private_data,
1636                                     struct extent_state *orig, u64 split)
1637 {
1638         struct inode *inode = private_data;
1639         u64 size;
1640
1641         /* not delalloc, ignore it */
1642         if (!(orig->state & EXTENT_DELALLOC))
1643                 return;
1644
1645         size = orig->end - orig->start + 1;
1646         if (size > BTRFS_MAX_EXTENT_SIZE) {
1647                 u32 num_extents;
1648                 u64 new_size;
1649
1650                 /*
1651                  * See the explanation in btrfs_merge_extent_hook, the same
1652                  * applies here, just in reverse.
1653                  */
1654                 new_size = orig->end - split + 1;
1655                 num_extents = count_max_extents(new_size);
1656                 new_size = split - orig->start;
1657                 num_extents += count_max_extents(new_size);
1658                 if (count_max_extents(size) >= num_extents)
1659                         return;
1660         }
1661
1662         spin_lock(&BTRFS_I(inode)->lock);
1663         btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
1664         spin_unlock(&BTRFS_I(inode)->lock);
1665 }
1666
1667 /*
1668  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1669  * extents so we can keep track of new extents that are just merged onto old
1670  * extents, such as when we are doing sequential writes, so we can properly
1671  * account for the metadata space we'll need.
1672  */
1673 static void btrfs_merge_extent_hook(void *private_data,
1674                                     struct extent_state *new,
1675                                     struct extent_state *other)
1676 {
1677         struct inode *inode = private_data;
1678         u64 new_size, old_size;
1679         u32 num_extents;
1680
1681         /* not delalloc, ignore it */
1682         if (!(other->state & EXTENT_DELALLOC))
1683                 return;
1684
1685         if (new->start > other->start)
1686                 new_size = new->end - other->start + 1;
1687         else
1688                 new_size = other->end - new->start + 1;
1689
1690         /* we're not bigger than the max, unreserve the space and go */
1691         if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
1692                 spin_lock(&BTRFS_I(inode)->lock);
1693                 btrfs_mod_outstanding_extents(BTRFS_I(inode), -1);
1694                 spin_unlock(&BTRFS_I(inode)->lock);
1695                 return;
1696         }
1697
1698         /*
1699          * We have to add up either side to figure out how many extents were
1700          * accounted for before we merged into one big extent.  If the number of
1701          * extents we accounted for is <= the amount we need for the new range
1702          * then we can return, otherwise drop.  Think of it like this
1703          *
1704          * [ 4k][MAX_SIZE]
1705          *
1706          * So we've grown the extent by a MAX_SIZE extent, this would mean we
1707          * need 2 outstanding extents, on one side we have 1 and the other side
1708          * we have 1 so they are == and we can return.  But in this case
1709          *
1710          * [MAX_SIZE+4k][MAX_SIZE+4k]
1711          *
1712          * Each range on their own accounts for 2 extents, but merged together
1713          * they are only 3 extents worth of accounting, so we need to drop in
1714          * this case.
1715          */
1716         old_size = other->end - other->start + 1;
1717         num_extents = count_max_extents(old_size);
1718         old_size = new->end - new->start + 1;
1719         num_extents += count_max_extents(old_size);
1720         if (count_max_extents(new_size) >= num_extents)
1721                 return;
1722
1723         spin_lock(&BTRFS_I(inode)->lock);
1724         btrfs_mod_outstanding_extents(BTRFS_I(inode), -1);
1725         spin_unlock(&BTRFS_I(inode)->lock);
1726 }
1727
1728 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1729                                       struct inode *inode)
1730 {
1731         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1732
1733         spin_lock(&root->delalloc_lock);
1734         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1735                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1736                               &root->delalloc_inodes);
1737                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1738                         &BTRFS_I(inode)->runtime_flags);
1739                 root->nr_delalloc_inodes++;
1740                 if (root->nr_delalloc_inodes == 1) {
1741                         spin_lock(&fs_info->delalloc_root_lock);
1742                         BUG_ON(!list_empty(&root->delalloc_root));
1743                         list_add_tail(&root->delalloc_root,
1744                                       &fs_info->delalloc_roots);
1745                         spin_unlock(&fs_info->delalloc_root_lock);
1746                 }
1747         }
1748         spin_unlock(&root->delalloc_lock);
1749 }
1750
1751
1752 void __btrfs_del_delalloc_inode(struct btrfs_root *root,
1753                                 struct btrfs_inode *inode)
1754 {
1755         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
1756
1757         if (!list_empty(&inode->delalloc_inodes)) {
1758                 list_del_init(&inode->delalloc_inodes);
1759                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1760                           &inode->runtime_flags);
1761                 root->nr_delalloc_inodes--;
1762                 if (!root->nr_delalloc_inodes) {
1763                         ASSERT(list_empty(&root->delalloc_inodes));
1764                         spin_lock(&fs_info->delalloc_root_lock);
1765                         BUG_ON(list_empty(&root->delalloc_root));
1766                         list_del_init(&root->delalloc_root);
1767                         spin_unlock(&fs_info->delalloc_root_lock);
1768                 }
1769         }
1770 }
1771
1772 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1773                                      struct btrfs_inode *inode)
1774 {
1775         spin_lock(&root->delalloc_lock);
1776         __btrfs_del_delalloc_inode(root, inode);
1777         spin_unlock(&root->delalloc_lock);
1778 }
1779
1780 /*
1781  * extent_io.c set_bit_hook, used to track delayed allocation
1782  * bytes in this file, and to maintain the list of inodes that
1783  * have pending delalloc work to be done.
1784  */
1785 static void btrfs_set_bit_hook(void *private_data,
1786                                struct extent_state *state, unsigned *bits)
1787 {
1788         struct inode *inode = private_data;
1789
1790         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1791
1792         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1793                 WARN_ON(1);
1794         /*
1795          * set_bit and clear bit hooks normally require _irqsave/restore
1796          * but in this case, we are only testing for the DELALLOC
1797          * bit, which is only set or cleared with irqs on
1798          */
1799         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1800                 struct btrfs_root *root = BTRFS_I(inode)->root;
1801                 u64 len = state->end + 1 - state->start;
1802                 u32 num_extents = count_max_extents(len);
1803                 bool do_list = !btrfs_is_free_space_inode(BTRFS_I(inode));
1804
1805                 spin_lock(&BTRFS_I(inode)->lock);
1806                 btrfs_mod_outstanding_extents(BTRFS_I(inode), num_extents);
1807                 spin_unlock(&BTRFS_I(inode)->lock);
1808
1809                 /* For sanity tests */
1810                 if (btrfs_is_testing(fs_info))
1811                         return;
1812
1813                 percpu_counter_add_batch(&fs_info->delalloc_bytes, len,
1814                                          fs_info->delalloc_batch);
1815                 spin_lock(&BTRFS_I(inode)->lock);
1816                 BTRFS_I(inode)->delalloc_bytes += len;
1817                 if (*bits & EXTENT_DEFRAG)
1818                         BTRFS_I(inode)->defrag_bytes += len;
1819                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1820                                          &BTRFS_I(inode)->runtime_flags))
1821                         btrfs_add_delalloc_inodes(root, inode);
1822                 spin_unlock(&BTRFS_I(inode)->lock);
1823         }
1824
1825         if (!(state->state & EXTENT_DELALLOC_NEW) &&
1826             (*bits & EXTENT_DELALLOC_NEW)) {
1827                 spin_lock(&BTRFS_I(inode)->lock);
1828                 BTRFS_I(inode)->new_delalloc_bytes += state->end + 1 -
1829                         state->start;
1830                 spin_unlock(&BTRFS_I(inode)->lock);
1831         }
1832 }
1833
1834 /*
1835  * extent_io.c clear_bit_hook, see set_bit_hook for why
1836  */
1837 static void btrfs_clear_bit_hook(void *private_data,
1838                                  struct extent_state *state,
1839                                  unsigned *bits)
1840 {
1841         struct btrfs_inode *inode = BTRFS_I((struct inode *)private_data);
1842         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
1843         u64 len = state->end + 1 - state->start;
1844         u32 num_extents = count_max_extents(len);
1845
1846         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG)) {
1847                 spin_lock(&inode->lock);
1848                 inode->defrag_bytes -= len;
1849                 spin_unlock(&inode->lock);
1850         }
1851
1852         /*
1853          * set_bit and clear bit hooks normally require _irqsave/restore
1854          * but in this case, we are only testing for the DELALLOC
1855          * bit, which is only set or cleared with irqs on
1856          */
1857         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1858                 struct btrfs_root *root = inode->root;
1859                 bool do_list = !btrfs_is_free_space_inode(inode);
1860
1861                 spin_lock(&inode->lock);
1862                 btrfs_mod_outstanding_extents(inode, -num_extents);
1863                 spin_unlock(&inode->lock);
1864
1865                 /*
1866                  * We don't reserve metadata space for space cache inodes so we
1867                  * don't need to call dellalloc_release_metadata if there is an
1868                  * error.
1869                  */
1870                 if (*bits & EXTENT_CLEAR_META_RESV &&
1871                     root != fs_info->tree_root)
1872                         btrfs_delalloc_release_metadata(inode, len, false);
1873
1874                 /* For sanity tests. */
1875                 if (btrfs_is_testing(fs_info))
1876                         return;
1877
1878                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID &&
1879                     do_list && !(state->state & EXTENT_NORESERVE) &&
1880                     (*bits & EXTENT_CLEAR_DATA_RESV))
1881                         btrfs_free_reserved_data_space_noquota(
1882                                         &inode->vfs_inode,
1883                                         state->start, len);
1884
1885                 percpu_counter_add_batch(&fs_info->delalloc_bytes, -len,
1886                                          fs_info->delalloc_batch);
1887                 spin_lock(&inode->lock);
1888                 inode->delalloc_bytes -= len;
1889                 if (do_list && inode->delalloc_bytes == 0 &&
1890                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1891                                         &inode->runtime_flags))
1892                         btrfs_del_delalloc_inode(root, inode);
1893                 spin_unlock(&inode->lock);
1894         }
1895
1896         if ((state->state & EXTENT_DELALLOC_NEW) &&
1897             (*bits & EXTENT_DELALLOC_NEW)) {
1898                 spin_lock(&inode->lock);
1899                 ASSERT(inode->new_delalloc_bytes >= len);
1900                 inode->new_delalloc_bytes -= len;
1901                 spin_unlock(&inode->lock);
1902         }
1903 }
1904
1905 /*
1906  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1907  * we don't create bios that span stripes or chunks
1908  *
1909  * return 1 if page cannot be merged to bio
1910  * return 0 if page can be merged to bio
1911  * return error otherwise
1912  */
1913 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1914                          size_t size, struct bio *bio,
1915                          unsigned long bio_flags)
1916 {
1917         struct inode *inode = page->mapping->host;
1918         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1919         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1920         u64 length = 0;
1921         u64 map_length;
1922         int ret;
1923
1924         if (bio_flags & EXTENT_BIO_COMPRESSED)
1925                 return 0;
1926
1927         length = bio->bi_iter.bi_size;
1928         map_length = length;
1929         ret = btrfs_map_block(fs_info, btrfs_op(bio), logical, &map_length,
1930                               NULL, 0);
1931         if (ret < 0)
1932                 return ret;
1933         if (map_length < length + size)
1934                 return 1;
1935         return 0;
1936 }
1937
1938 /*
1939  * in order to insert checksums into the metadata in large chunks,
1940  * we wait until bio submission time.   All the pages in the bio are
1941  * checksummed and sums are attached onto the ordered extent record.
1942  *
1943  * At IO completion time the cums attached on the ordered extent record
1944  * are inserted into the btree
1945  */
1946 static blk_status_t btrfs_submit_bio_start(void *private_data, struct bio *bio,
1947                                     u64 bio_offset)
1948 {
1949         struct inode *inode = private_data;
1950         blk_status_t ret = 0;
1951
1952         ret = btrfs_csum_one_bio(inode, bio, 0, 0);
1953         BUG_ON(ret); /* -ENOMEM */
1954         return 0;
1955 }
1956
1957 /*
1958  * in order to insert checksums into the metadata in large chunks,
1959  * we wait until bio submission time.   All the pages in the bio are
1960  * checksummed and sums are attached onto the ordered extent record.
1961  *
1962  * At IO completion time the cums attached on the ordered extent record
1963  * are inserted into the btree
1964  */
1965 static blk_status_t btrfs_submit_bio_done(void *private_data, struct bio *bio,
1966                           int mirror_num)
1967 {
1968         struct inode *inode = private_data;
1969         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1970         blk_status_t ret;
1971
1972         ret = btrfs_map_bio(fs_info, bio, mirror_num, 1);
1973         if (ret) {
1974                 bio->bi_status = ret;
1975                 bio_endio(bio);
1976         }
1977         return ret;
1978 }
1979
1980 /*
1981  * extent_io.c submission hook. This does the right thing for csum calculation
1982  * on write, or reading the csums from the tree before a read.
1983  *
1984  * Rules about async/sync submit,
1985  * a) read:                             sync submit
1986  *
1987  * b) write without checksum:           sync submit
1988  *
1989  * c) write with checksum:
1990  *    c-1) if bio is issued by fsync:   sync submit
1991  *         (sync_writers != 0)
1992  *
1993  *    c-2) if root is reloc root:       sync submit
1994  *         (only in case of buffered IO)
1995  *
1996  *    c-3) otherwise:                   async submit
1997  */
1998 static blk_status_t btrfs_submit_bio_hook(void *private_data, struct bio *bio,
1999                                  int mirror_num, unsigned long bio_flags,
2000                                  u64 bio_offset)
2001 {
2002         struct inode *inode = private_data;
2003         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2004         struct btrfs_root *root = BTRFS_I(inode)->root;
2005         enum btrfs_wq_endio_type metadata = BTRFS_WQ_ENDIO_DATA;
2006         blk_status_t ret = 0;
2007         int skip_sum;
2008         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
2009
2010         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
2011
2012         if (btrfs_is_free_space_inode(BTRFS_I(inode)))
2013                 metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
2014
2015         if (bio_op(bio) != REQ_OP_WRITE) {
2016                 ret = btrfs_bio_wq_end_io(fs_info, bio, metadata);
2017                 if (ret)
2018                         goto out;
2019
2020                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
2021                         ret = btrfs_submit_compressed_read(inode, bio,
2022                                                            mirror_num,
2023                                                            bio_flags);
2024                         goto out;
2025                 } else if (!skip_sum) {
2026                         ret = btrfs_lookup_bio_sums(inode, bio, NULL);
2027                         if (ret)
2028                                 goto out;
2029                 }
2030                 goto mapit;
2031         } else if (async && !skip_sum) {
2032                 /* csum items have already been cloned */
2033                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2034                         goto mapit;
2035                 /* we're doing a write, do the async checksumming */
2036                 ret = btrfs_wq_submit_bio(fs_info, bio, mirror_num, bio_flags,
2037                                           bio_offset, inode,
2038                                           btrfs_submit_bio_start,
2039                                           btrfs_submit_bio_done);
2040                 goto out;
2041         } else if (!skip_sum) {
2042                 ret = btrfs_csum_one_bio(inode, bio, 0, 0);
2043                 if (ret)
2044                         goto out;
2045         }
2046
2047 mapit:
2048         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
2049
2050 out:
2051         if (ret) {
2052                 bio->bi_status = ret;
2053                 bio_endio(bio);
2054         }
2055         return ret;
2056 }
2057
2058 /*
2059  * given a list of ordered sums record them in the inode.  This happens
2060  * at IO completion time based on sums calculated at bio submission time.
2061  */
2062 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
2063                              struct inode *inode, struct list_head *list)
2064 {
2065         struct btrfs_ordered_sum *sum;
2066         int ret;
2067
2068         list_for_each_entry(sum, list, list) {
2069                 trans->adding_csums = true;
2070                 ret = btrfs_csum_file_blocks(trans,
2071                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
2072                 trans->adding_csums = false;
2073                 if (ret)
2074                         return ret;
2075         }
2076         return 0;
2077 }
2078
2079 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
2080                               unsigned int extra_bits,
2081                               struct extent_state **cached_state, int dedupe)
2082 {
2083         WARN_ON((end & (PAGE_SIZE - 1)) == 0);
2084         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
2085                                    extra_bits, cached_state);
2086 }
2087
2088 /* see btrfs_writepage_start_hook for details on why this is required */
2089 struct btrfs_writepage_fixup {
2090         struct page *page;
2091         struct btrfs_work work;
2092 };
2093
2094 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
2095 {
2096         struct btrfs_writepage_fixup *fixup;
2097         struct btrfs_ordered_extent *ordered;
2098         struct extent_state *cached_state = NULL;
2099         struct extent_changeset *data_reserved = NULL;
2100         struct page *page;
2101         struct inode *inode;
2102         u64 page_start;
2103         u64 page_end;
2104         int ret;
2105
2106         fixup = container_of(work, struct btrfs_writepage_fixup, work);
2107         page = fixup->page;
2108 again:
2109         lock_page(page);
2110         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
2111                 ClearPageChecked(page);
2112                 goto out_page;
2113         }
2114
2115         inode = page->mapping->host;
2116         page_start = page_offset(page);
2117         page_end = page_offset(page) + PAGE_SIZE - 1;
2118
2119         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
2120                          &cached_state);
2121
2122         /* already ordered? We're done */
2123         if (PagePrivate2(page))
2124                 goto out;
2125
2126         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), page_start,
2127                                         PAGE_SIZE);
2128         if (ordered) {
2129                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
2130                                      page_end, &cached_state);
2131                 unlock_page(page);
2132                 btrfs_start_ordered_extent(inode, ordered, 1);
2133                 btrfs_put_ordered_extent(ordered);
2134                 goto again;
2135         }
2136
2137         ret = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start,
2138                                            PAGE_SIZE);
2139         if (ret) {
2140                 mapping_set_error(page->mapping, ret);
2141                 end_extent_writepage(page, ret, page_start, page_end);
2142                 ClearPageChecked(page);
2143                 goto out;
2144          }
2145
2146         ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
2147                                         &cached_state, 0);
2148         if (ret) {
2149                 mapping_set_error(page->mapping, ret);
2150                 end_extent_writepage(page, ret, page_start, page_end);
2151                 ClearPageChecked(page);
2152                 goto out;
2153         }
2154
2155         ClearPageChecked(page);
2156         set_page_dirty(page);
2157         btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, false);
2158 out:
2159         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
2160                              &cached_state);
2161 out_page:
2162         unlock_page(page);
2163         put_page(page);
2164         kfree(fixup);
2165         extent_changeset_free(data_reserved);
2166 }
2167
2168 /*
2169  * There are a few paths in the higher layers of the kernel that directly
2170  * set the page dirty bit without asking the filesystem if it is a
2171  * good idea.  This causes problems because we want to make sure COW
2172  * properly happens and the data=ordered rules are followed.
2173  *
2174  * In our case any range that doesn't have the ORDERED bit set
2175  * hasn't been properly setup for IO.  We kick off an async process
2176  * to fix it up.  The async helper will wait for ordered extents, set
2177  * the delalloc bit and make it safe to write the page.
2178  */
2179 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
2180 {
2181         struct inode *inode = page->mapping->host;
2182         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2183         struct btrfs_writepage_fixup *fixup;
2184
2185         /* this page is properly in the ordered list */
2186         if (TestClearPagePrivate2(page))
2187                 return 0;
2188
2189         if (PageChecked(page))
2190                 return -EAGAIN;
2191
2192         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
2193         if (!fixup)
2194                 return -EAGAIN;
2195
2196         SetPageChecked(page);
2197         get_page(page);
2198         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
2199                         btrfs_writepage_fixup_worker, NULL, NULL);
2200         fixup->page = page;
2201         btrfs_queue_work(fs_info->fixup_workers, &fixup->work);
2202         return -EBUSY;
2203 }
2204
2205 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
2206                                        struct inode *inode, u64 file_pos,
2207                                        u64 disk_bytenr, u64 disk_num_bytes,
2208                                        u64 num_bytes, u64 ram_bytes,
2209                                        u8 compression, u8 encryption,
2210                                        u16 other_encoding, int extent_type)
2211 {
2212         struct btrfs_root *root = BTRFS_I(inode)->root;
2213         struct btrfs_file_extent_item *fi;
2214         struct btrfs_path *path;
2215         struct extent_buffer *leaf;
2216         struct btrfs_key ins;
2217         u64 qg_released;
2218         int extent_inserted = 0;
2219         int ret;
2220
2221         path = btrfs_alloc_path();
2222         if (!path)
2223                 return -ENOMEM;
2224
2225         /*
2226          * we may be replacing one extent in the tree with another.
2227          * The new extent is pinned in the extent map, and we don't want
2228          * to drop it from the cache until it is completely in the btree.
2229          *
2230          * So, tell btrfs_drop_extents to leave this extent in the cache.
2231          * the caller is expected to unpin it and allow it to be merged
2232          * with the others.
2233          */
2234         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
2235                                    file_pos + num_bytes, NULL, 0,
2236                                    1, sizeof(*fi), &extent_inserted);
2237         if (ret)
2238                 goto out;
2239
2240         if (!extent_inserted) {
2241                 ins.objectid = btrfs_ino(BTRFS_I(inode));
2242                 ins.offset = file_pos;
2243                 ins.type = BTRFS_EXTENT_DATA_KEY;
2244
2245                 path->leave_spinning = 1;
2246                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2247                                               sizeof(*fi));
2248                 if (ret)
2249                         goto out;
2250         }
2251         leaf = path->nodes[0];
2252         fi = btrfs_item_ptr(leaf, path->slots[0],
2253                             struct btrfs_file_extent_item);
2254         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2255         btrfs_set_file_extent_type(leaf, fi, extent_type);
2256         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2257         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2258         btrfs_set_file_extent_offset(leaf, fi, 0);
2259         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2260         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2261         btrfs_set_file_extent_compression(leaf, fi, compression);
2262         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2263         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2264
2265         btrfs_mark_buffer_dirty(leaf);
2266         btrfs_release_path(path);
2267
2268         inode_add_bytes(inode, num_bytes);
2269
2270         ins.objectid = disk_bytenr;
2271         ins.offset = disk_num_bytes;
2272         ins.type = BTRFS_EXTENT_ITEM_KEY;
2273
2274         /*
2275          * Release the reserved range from inode dirty range map, as it is
2276          * already moved into delayed_ref_head
2277          */
2278         ret = btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
2279         if (ret < 0)
2280                 goto out;
2281         qg_released = ret;
2282         ret = btrfs_alloc_reserved_file_extent(trans, root,
2283                                                btrfs_ino(BTRFS_I(inode)),
2284                                                file_pos, qg_released, &ins);
2285 out:
2286         btrfs_free_path(path);
2287
2288         return ret;
2289 }
2290
2291 /* snapshot-aware defrag */
2292 struct sa_defrag_extent_backref {
2293         struct rb_node node;
2294         struct old_sa_defrag_extent *old;
2295         u64 root_id;
2296         u64 inum;
2297         u64 file_pos;
2298         u64 extent_offset;
2299         u64 num_bytes;
2300         u64 generation;
2301 };
2302
2303 struct old_sa_defrag_extent {
2304         struct list_head list;
2305         struct new_sa_defrag_extent *new;
2306
2307         u64 extent_offset;
2308         u64 bytenr;
2309         u64 offset;
2310         u64 len;
2311         int count;
2312 };
2313
2314 struct new_sa_defrag_extent {
2315         struct rb_root root;
2316         struct list_head head;
2317         struct btrfs_path *path;
2318         struct inode *inode;
2319         u64 file_pos;
2320         u64 len;
2321         u64 bytenr;
2322         u64 disk_len;
2323         u8 compress_type;
2324 };
2325
2326 static int backref_comp(struct sa_defrag_extent_backref *b1,
2327                         struct sa_defrag_extent_backref *b2)
2328 {
2329         if (b1->root_id < b2->root_id)
2330                 return -1;
2331         else if (b1->root_id > b2->root_id)
2332                 return 1;
2333
2334         if (b1->inum < b2->inum)
2335                 return -1;
2336         else if (b1->inum > b2->inum)
2337                 return 1;
2338
2339         if (b1->file_pos < b2->file_pos)
2340                 return -1;
2341         else if (b1->file_pos > b2->file_pos)
2342                 return 1;
2343
2344         /*
2345          * [------------------------------] ===> (a range of space)
2346          *     |<--->|   |<---->| =============> (fs/file tree A)
2347          * |<---------------------------->| ===> (fs/file tree B)
2348          *
2349          * A range of space can refer to two file extents in one tree while
2350          * refer to only one file extent in another tree.
2351          *
2352          * So we may process a disk offset more than one time(two extents in A)
2353          * and locate at the same extent(one extent in B), then insert two same
2354          * backrefs(both refer to the extent in B).
2355          */
2356         return 0;
2357 }
2358
2359 static void backref_insert(struct rb_root *root,
2360                            struct sa_defrag_extent_backref *backref)
2361 {
2362         struct rb_node **p = &root->rb_node;
2363         struct rb_node *parent = NULL;
2364         struct sa_defrag_extent_backref *entry;
2365         int ret;
2366
2367         while (*p) {
2368                 parent = *p;
2369                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2370
2371                 ret = backref_comp(backref, entry);
2372                 if (ret < 0)
2373                         p = &(*p)->rb_left;
2374                 else
2375                         p = &(*p)->rb_right;
2376         }
2377
2378         rb_link_node(&backref->node, parent, p);
2379         rb_insert_color(&backref->node, root);
2380 }
2381
2382 /*
2383  * Note the backref might has changed, and in this case we just return 0.
2384  */
2385 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2386                                        void *ctx)
2387 {
2388         struct btrfs_file_extent_item *extent;
2389         struct old_sa_defrag_extent *old = ctx;
2390         struct new_sa_defrag_extent *new = old->new;
2391         struct btrfs_path *path = new->path;
2392         struct btrfs_key key;
2393         struct btrfs_root *root;
2394         struct sa_defrag_extent_backref *backref;
2395         struct extent_buffer *leaf;
2396         struct inode *inode = new->inode;
2397         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2398         int slot;
2399         int ret;
2400         u64 extent_offset;
2401         u64 num_bytes;
2402
2403         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2404             inum == btrfs_ino(BTRFS_I(inode)))
2405                 return 0;
2406
2407         key.objectid = root_id;
2408         key.type = BTRFS_ROOT_ITEM_KEY;
2409         key.offset = (u64)-1;
2410
2411         root = btrfs_read_fs_root_no_name(fs_info, &key);
2412         if (IS_ERR(root)) {
2413                 if (PTR_ERR(root) == -ENOENT)
2414                         return 0;
2415                 WARN_ON(1);
2416                 btrfs_debug(fs_info, "inum=%llu, offset=%llu, root_id=%llu",
2417                          inum, offset, root_id);
2418                 return PTR_ERR(root);
2419         }
2420
2421         key.objectid = inum;
2422         key.type = BTRFS_EXTENT_DATA_KEY;
2423         if (offset > (u64)-1 << 32)
2424                 key.offset = 0;
2425         else
2426                 key.offset = offset;
2427
2428         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2429         if (WARN_ON(ret < 0))
2430                 return ret;
2431         ret = 0;
2432
2433         while (1) {
2434                 cond_resched();
2435
2436                 leaf = path->nodes[0];
2437                 slot = path->slots[0];
2438
2439                 if (slot >= btrfs_header_nritems(leaf)) {
2440                         ret = btrfs_next_leaf(root, path);
2441                         if (ret < 0) {
2442                                 goto out;
2443                         } else if (ret > 0) {
2444                                 ret = 0;
2445                                 goto out;
2446                         }
2447                         continue;
2448                 }
2449
2450                 path->slots[0]++;
2451
2452                 btrfs_item_key_to_cpu(leaf, &key, slot);
2453
2454                 if (key.objectid > inum)
2455                         goto out;
2456
2457                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2458                         continue;
2459
2460                 extent = btrfs_item_ptr(leaf, slot,
2461                                         struct btrfs_file_extent_item);
2462
2463                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2464                         continue;
2465
2466                 /*
2467                  * 'offset' refers to the exact key.offset,
2468                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2469                  * (key.offset - extent_offset).
2470                  */
2471                 if (key.offset != offset)
2472                         continue;
2473
2474                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2475                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2476
2477                 if (extent_offset >= old->extent_offset + old->offset +
2478                     old->len || extent_offset + num_bytes <=
2479                     old->extent_offset + old->offset)
2480                         continue;
2481                 break;
2482         }
2483
2484         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2485         if (!backref) {
2486                 ret = -ENOENT;
2487                 goto out;
2488         }
2489
2490         backref->root_id = root_id;
2491         backref->inum = inum;
2492         backref->file_pos = offset;
2493         backref->num_bytes = num_bytes;
2494         backref->extent_offset = extent_offset;
2495         backref->generation = btrfs_file_extent_generation(leaf, extent);
2496         backref->old = old;
2497         backref_insert(&new->root, backref);
2498         old->count++;
2499 out:
2500         btrfs_release_path(path);
2501         WARN_ON(ret);
2502         return ret;
2503 }
2504
2505 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2506                                    struct new_sa_defrag_extent *new)
2507 {
2508         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2509         struct old_sa_defrag_extent *old, *tmp;
2510         int ret;
2511
2512         new->path = path;
2513
2514         list_for_each_entry_safe(old, tmp, &new->head, list) {
2515                 ret = iterate_inodes_from_logical(old->bytenr +
2516                                                   old->extent_offset, fs_info,
2517                                                   path, record_one_backref,
2518                                                   old, false);
2519                 if (ret < 0 && ret != -ENOENT)
2520                         return false;
2521
2522                 /* no backref to be processed for this extent */
2523                 if (!old->count) {
2524                         list_del(&old->list);
2525                         kfree(old);
2526                 }
2527         }
2528
2529         if (list_empty(&new->head))
2530                 return false;
2531
2532         return true;
2533 }
2534
2535 static int relink_is_mergable(struct extent_buffer *leaf,
2536                               struct btrfs_file_extent_item *fi,
2537                               struct new_sa_defrag_extent *new)
2538 {
2539         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2540                 return 0;
2541
2542         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2543                 return 0;
2544
2545         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2546                 return 0;
2547
2548         if (btrfs_file_extent_encryption(leaf, fi) ||
2549             btrfs_file_extent_other_encoding(leaf, fi))
2550                 return 0;
2551
2552         return 1;
2553 }
2554
2555 /*
2556  * Note the backref might has changed, and in this case we just return 0.
2557  */
2558 static noinline int relink_extent_backref(struct btrfs_path *path,
2559                                  struct sa_defrag_extent_backref *prev,
2560                                  struct sa_defrag_extent_backref *backref)
2561 {
2562         struct btrfs_file_extent_item *extent;
2563         struct btrfs_file_extent_item *item;
2564         struct btrfs_ordered_extent *ordered;
2565         struct btrfs_trans_handle *trans;
2566         struct btrfs_root *root;
2567         struct btrfs_key key;
2568         struct extent_buffer *leaf;
2569         struct old_sa_defrag_extent *old = backref->old;
2570         struct new_sa_defrag_extent *new = old->new;
2571         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2572         struct inode *inode;
2573         struct extent_state *cached = NULL;
2574         int ret = 0;
2575         u64 start;
2576         u64 len;
2577         u64 lock_start;
2578         u64 lock_end;
2579         bool merge = false;
2580         int index;
2581
2582         if (prev && prev->root_id == backref->root_id &&
2583             prev->inum == backref->inum &&
2584             prev->file_pos + prev->num_bytes == backref->file_pos)
2585                 merge = true;
2586
2587         /* step 1: get root */
2588         key.objectid = backref->root_id;
2589         key.type = BTRFS_ROOT_ITEM_KEY;
2590         key.offset = (u64)-1;
2591
2592         index = srcu_read_lock(&fs_info->subvol_srcu);
2593
2594         root = btrfs_read_fs_root_no_name(fs_info, &key);
2595         if (IS_ERR(root)) {
2596                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2597                 if (PTR_ERR(root) == -ENOENT)
2598                         return 0;
2599                 return PTR_ERR(root);
2600         }
2601
2602         if (btrfs_root_readonly(root)) {
2603                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2604                 return 0;
2605         }
2606
2607         /* step 2: get inode */
2608         key.objectid = backref->inum;
2609         key.type = BTRFS_INODE_ITEM_KEY;
2610         key.offset = 0;
2611
2612         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2613         if (IS_ERR(inode)) {
2614                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2615                 return 0;
2616         }
2617
2618         srcu_read_unlock(&fs_info->subvol_srcu, index);
2619
2620         /* step 3: relink backref */
2621         lock_start = backref->file_pos;
2622         lock_end = backref->file_pos + backref->num_bytes - 1;
2623         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2624                          &cached);
2625
2626         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2627         if (ordered) {
2628                 btrfs_put_ordered_extent(ordered);
2629                 goto out_unlock;
2630         }
2631
2632         trans = btrfs_join_transaction(root);
2633         if (IS_ERR(trans)) {
2634                 ret = PTR_ERR(trans);
2635                 goto out_unlock;
2636         }
2637
2638         key.objectid = backref->inum;
2639         key.type = BTRFS_EXTENT_DATA_KEY;
2640         key.offset = backref->file_pos;
2641
2642         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2643         if (ret < 0) {
2644                 goto out_free_path;
2645         } else if (ret > 0) {
2646                 ret = 0;
2647                 goto out_free_path;
2648         }
2649
2650         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2651                                 struct btrfs_file_extent_item);
2652
2653         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2654             backref->generation)
2655                 goto out_free_path;
2656
2657         btrfs_release_path(path);
2658
2659         start = backref->file_pos;
2660         if (backref->extent_offset < old->extent_offset + old->offset)
2661                 start += old->extent_offset + old->offset -
2662                          backref->extent_offset;
2663
2664         len = min(backref->extent_offset + backref->num_bytes,
2665                   old->extent_offset + old->offset + old->len);
2666         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2667
2668         ret = btrfs_drop_extents(trans, root, inode, start,
2669                                  start + len, 1);
2670         if (ret)
2671                 goto out_free_path;
2672 again:
2673         key.objectid = btrfs_ino(BTRFS_I(inode));
2674         key.type = BTRFS_EXTENT_DATA_KEY;
2675         key.offset = start;
2676
2677         path->leave_spinning = 1;
2678         if (merge) {
2679                 struct btrfs_file_extent_item *fi;
2680                 u64 extent_len;
2681                 struct btrfs_key found_key;
2682
2683                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2684                 if (ret < 0)
2685                         goto out_free_path;
2686
2687                 path->slots[0]--;
2688                 leaf = path->nodes[0];
2689                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2690
2691                 fi = btrfs_item_ptr(leaf, path->slots[0],
2692                                     struct btrfs_file_extent_item);
2693                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2694
2695                 if (extent_len + found_key.offset == start &&
2696                     relink_is_mergable(leaf, fi, new)) {
2697                         btrfs_set_file_extent_num_bytes(leaf, fi,
2698                                                         extent_len + len);
2699                         btrfs_mark_buffer_dirty(leaf);
2700                         inode_add_bytes(inode, len);
2701
2702                         ret = 1;
2703                         goto out_free_path;
2704                 } else {
2705                         merge = false;
2706                         btrfs_release_path(path);
2707                         goto again;
2708                 }
2709         }
2710
2711         ret = btrfs_insert_empty_item(trans, root, path, &key,
2712                                         sizeof(*extent));
2713         if (ret) {
2714                 btrfs_abort_transaction(trans, ret);
2715                 goto out_free_path;
2716         }
2717
2718         leaf = path->nodes[0];
2719         item = btrfs_item_ptr(leaf, path->slots[0],
2720                                 struct btrfs_file_extent_item);
2721         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2722         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2723         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2724         btrfs_set_file_extent_num_bytes(leaf, item, len);
2725         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2726         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2727         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2728         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2729         btrfs_set_file_extent_encryption(leaf, item, 0);
2730         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2731
2732         btrfs_mark_buffer_dirty(leaf);
2733         inode_add_bytes(inode, len);
2734         btrfs_release_path(path);
2735
2736         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2737                         new->disk_len, 0,
2738                         backref->root_id, backref->inum,
2739                         new->file_pos); /* start - extent_offset */
2740         if (ret) {
2741                 btrfs_abort_transaction(trans, ret);
2742                 goto out_free_path;
2743         }
2744
2745         ret = 1;
2746 out_free_path:
2747         btrfs_release_path(path);
2748         path->leave_spinning = 0;
2749         btrfs_end_transaction(trans);
2750 out_unlock:
2751         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2752                              &cached);
2753         iput(inode);
2754         return ret;
2755 }
2756
2757 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2758 {
2759         struct old_sa_defrag_extent *old, *tmp;
2760
2761         if (!new)
2762                 return;
2763
2764         list_for_each_entry_safe(old, tmp, &new->head, list) {
2765                 kfree(old);
2766         }
2767         kfree(new);
2768 }
2769
2770 static void relink_file_extents(struct new_sa_defrag_extent *new)
2771 {
2772         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2773         struct btrfs_path *path;
2774         struct sa_defrag_extent_backref *backref;
2775         struct sa_defrag_extent_backref *prev = NULL;
2776         struct inode *inode;
2777         struct rb_node *node;
2778         int ret;
2779
2780         inode = new->inode;
2781
2782         path = btrfs_alloc_path();
2783         if (!path)
2784                 return;
2785
2786         if (!record_extent_backrefs(path, new)) {
2787                 btrfs_free_path(path);
2788                 goto out;
2789         }
2790         btrfs_release_path(path);
2791
2792         while (1) {
2793                 node = rb_first(&new->root);
2794                 if (!node)
2795                         break;
2796                 rb_erase(node, &new->root);
2797
2798                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2799
2800                 ret = relink_extent_backref(path, prev, backref);
2801                 WARN_ON(ret < 0);
2802
2803                 kfree(prev);
2804
2805                 if (ret == 1)
2806                         prev = backref;
2807                 else
2808                         prev = NULL;
2809                 cond_resched();
2810         }
2811         kfree(prev);
2812
2813         btrfs_free_path(path);
2814 out:
2815         free_sa_defrag_extent(new);
2816
2817         atomic_dec(&fs_info->defrag_running);
2818         wake_up(&fs_info->transaction_wait);
2819 }
2820
2821 static struct new_sa_defrag_extent *
2822 record_old_file_extents(struct inode *inode,
2823                         struct btrfs_ordered_extent *ordered)
2824 {
2825         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2826         struct btrfs_root *root = BTRFS_I(inode)->root;
2827         struct btrfs_path *path;
2828         struct btrfs_key key;
2829         struct old_sa_defrag_extent *old;
2830         struct new_sa_defrag_extent *new;
2831         int ret;
2832
2833         new = kmalloc(sizeof(*new), GFP_NOFS);
2834         if (!new)
2835                 return NULL;
2836
2837         new->inode = inode;
2838         new->file_pos = ordered->file_offset;
2839         new->len = ordered->len;
2840         new->bytenr = ordered->start;
2841         new->disk_len = ordered->disk_len;
2842         new->compress_type = ordered->compress_type;
2843         new->root = RB_ROOT;
2844         INIT_LIST_HEAD(&new->head);
2845
2846         path = btrfs_alloc_path();
2847         if (!path)
2848                 goto out_kfree;
2849
2850         key.objectid = btrfs_ino(BTRFS_I(inode));
2851         key.type = BTRFS_EXTENT_DATA_KEY;
2852         key.offset = new->file_pos;
2853
2854         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2855         if (ret < 0)
2856                 goto out_free_path;
2857         if (ret > 0 && path->slots[0] > 0)
2858                 path->slots[0]--;
2859
2860         /* find out all the old extents for the file range */
2861         while (1) {
2862                 struct btrfs_file_extent_item *extent;
2863                 struct extent_buffer *l;
2864                 int slot;
2865                 u64 num_bytes;
2866                 u64 offset;
2867                 u64 end;
2868                 u64 disk_bytenr;
2869                 u64 extent_offset;
2870
2871                 l = path->nodes[0];
2872                 slot = path->slots[0];
2873
2874                 if (slot >= btrfs_header_nritems(l)) {
2875                         ret = btrfs_next_leaf(root, path);
2876                         if (ret < 0)
2877                                 goto out_free_path;
2878                         else if (ret > 0)
2879                                 break;
2880                         continue;
2881                 }
2882
2883                 btrfs_item_key_to_cpu(l, &key, slot);
2884
2885                 if (key.objectid != btrfs_ino(BTRFS_I(inode)))
2886                         break;
2887                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2888                         break;
2889                 if (key.offset >= new->file_pos + new->len)
2890                         break;
2891
2892                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2893
2894                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2895                 if (key.offset + num_bytes < new->file_pos)
2896                         goto next;
2897
2898                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2899                 if (!disk_bytenr)
2900                         goto next;
2901
2902                 extent_offset = btrfs_file_extent_offset(l, extent);
2903
2904                 old = kmalloc(sizeof(*old), GFP_NOFS);
2905                 if (!old)
2906                         goto out_free_path;
2907
2908                 offset = max(new->file_pos, key.offset);
2909                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2910
2911                 old->bytenr = disk_bytenr;
2912                 old->extent_offset = extent_offset;
2913                 old->offset = offset - key.offset;
2914                 old->len = end - offset;
2915                 old->new = new;
2916                 old->count = 0;
2917                 list_add_tail(&old->list, &new->head);
2918 next:
2919                 path->slots[0]++;
2920                 cond_resched();
2921         }
2922
2923         btrfs_free_path(path);
2924         atomic_inc(&fs_info->defrag_running);
2925
2926         return new;
2927
2928 out_free_path:
2929         btrfs_free_path(path);
2930 out_kfree:
2931         free_sa_defrag_extent(new);
2932         return NULL;
2933 }
2934
2935 static void btrfs_release_delalloc_bytes(struct btrfs_fs_info *fs_info,
2936                                          u64 start, u64 len)
2937 {
2938         struct btrfs_block_group_cache *cache;
2939
2940         cache = btrfs_lookup_block_group(fs_info, start);
2941         ASSERT(cache);
2942
2943         spin_lock(&cache->lock);
2944         cache->delalloc_bytes -= len;
2945         spin_unlock(&cache->lock);
2946
2947         btrfs_put_block_group(cache);
2948 }
2949
2950 /* as ordered data IO finishes, this gets called so we can finish
2951  * an ordered extent if the range of bytes in the file it covers are
2952  * fully written.
2953  */
2954 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2955 {
2956         struct inode *inode = ordered_extent->inode;
2957         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2958         struct btrfs_root *root = BTRFS_I(inode)->root;
2959         struct btrfs_trans_handle *trans = NULL;
2960         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2961         struct extent_state *cached_state = NULL;
2962         struct new_sa_defrag_extent *new = NULL;
2963         int compress_type = 0;
2964         int ret = 0;
2965         u64 logical_len = ordered_extent->len;
2966         bool nolock;
2967         bool truncated = false;
2968         bool range_locked = false;
2969         bool clear_new_delalloc_bytes = false;
2970
2971         if (!test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2972             !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags) &&
2973             !test_bit(BTRFS_ORDERED_DIRECT, &ordered_extent->flags))
2974                 clear_new_delalloc_bytes = true;
2975
2976         nolock = btrfs_is_free_space_inode(BTRFS_I(inode));
2977
2978         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2979                 ret = -EIO;
2980                 goto out;
2981         }
2982
2983         btrfs_free_io_failure_record(BTRFS_I(inode),
2984                         ordered_extent->file_offset,
2985                         ordered_extent->file_offset +
2986                         ordered_extent->len - 1);
2987
2988         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2989                 truncated = true;
2990                 logical_len = ordered_extent->truncated_len;
2991                 /* Truncated the entire extent, don't bother adding */
2992                 if (!logical_len)
2993                         goto out;
2994         }
2995
2996         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2997                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2998
2999                 /*
3000                  * For mwrite(mmap + memset to write) case, we still reserve
3001                  * space for NOCOW range.
3002                  * As NOCOW won't cause a new delayed ref, just free the space
3003                  */
3004                 btrfs_qgroup_free_data(inode, NULL, ordered_extent->file_offset,
3005                                        ordered_extent->len);
3006                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
3007                 if (nolock)
3008                         trans = btrfs_join_transaction_nolock(root);
3009                 else
3010                         trans = btrfs_join_transaction(root);
3011                 if (IS_ERR(trans)) {
3012                         ret = PTR_ERR(trans);
3013                         trans = NULL;
3014                         goto out;
3015                 }
3016                 trans->block_rsv = &BTRFS_I(inode)->block_rsv;
3017                 ret = btrfs_update_inode_fallback(trans, root, inode);
3018                 if (ret) /* -ENOMEM or corruption */
3019                         btrfs_abort_transaction(trans, ret);
3020                 goto out;
3021         }
3022
3023         range_locked = true;
3024         lock_extent_bits(io_tree, ordered_extent->file_offset,
3025                          ordered_extent->file_offset + ordered_extent->len - 1,
3026                          &cached_state);
3027
3028         ret = test_range_bit(io_tree, ordered_extent->file_offset,
3029                         ordered_extent->file_offset + ordered_extent->len - 1,
3030                         EXTENT_DEFRAG, 0, cached_state);
3031         if (ret) {
3032                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
3033                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
3034                         /* the inode is shared */
3035                         new = record_old_file_extents(inode, ordered_extent);
3036
3037                 clear_extent_bit(io_tree, ordered_extent->file_offset,
3038                         ordered_extent->file_offset + ordered_extent->len - 1,
3039                         EXTENT_DEFRAG, 0, 0, &cached_state);
3040         }
3041
3042         if (nolock)
3043                 trans = btrfs_join_transaction_nolock(root);
3044         else
3045                 trans = btrfs_join_transaction(root);
3046         if (IS_ERR(trans)) {
3047                 ret = PTR_ERR(trans);
3048                 trans = NULL;
3049                 goto out;
3050         }
3051
3052         trans->block_rsv = &BTRFS_I(inode)->block_rsv;
3053
3054         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
3055                 compress_type = ordered_extent->compress_type;
3056         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
3057                 BUG_ON(compress_type);
3058                 btrfs_qgroup_free_data(inode, NULL, ordered_extent->file_offset,
3059                                        ordered_extent->len);
3060                 ret = btrfs_mark_extent_written(trans, BTRFS_I(inode),
3061                                                 ordered_extent->file_offset,
3062                                                 ordered_extent->file_offset +
3063                                                 logical_len);
3064         } else {
3065                 BUG_ON(root == fs_info->tree_root);
3066                 ret = insert_reserved_file_extent(trans, inode,
3067                                                 ordered_extent->file_offset,
3068                                                 ordered_extent->start,
3069                                                 ordered_extent->disk_len,
3070                                                 logical_len, logical_len,
3071                                                 compress_type, 0, 0,
3072                                                 BTRFS_FILE_EXTENT_REG);
3073                 if (!ret)
3074                         btrfs_release_delalloc_bytes(fs_info,
3075                                                      ordered_extent->start,
3076                                                      ordered_extent->disk_len);
3077         }
3078         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
3079                            ordered_extent->file_offset, ordered_extent->len,
3080                            trans->transid);
3081         if (ret < 0) {
3082                 btrfs_abort_transaction(trans, ret);
3083                 goto out;
3084         }
3085
3086         ret = add_pending_csums(trans, inode, &ordered_extent->list);
3087         if (ret) {
3088                 btrfs_abort_transaction(trans, ret);
3089                 goto out;
3090         }
3091
3092         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
3093         ret = btrfs_update_inode_fallback(trans, root, inode);
3094         if (ret) { /* -ENOMEM or corruption */
3095                 btrfs_abort_transaction(trans, ret);
3096                 goto out;
3097         }
3098         ret = 0;
3099 out:
3100         if (range_locked || clear_new_delalloc_bytes) {
3101                 unsigned int clear_bits = 0;
3102
3103                 if (range_locked)
3104                         clear_bits |= EXTENT_LOCKED;
3105                 if (clear_new_delalloc_bytes)
3106                         clear_bits |= EXTENT_DELALLOC_NEW;
3107                 clear_extent_bit(&BTRFS_I(inode)->io_tree,
3108                                  ordered_extent->file_offset,
3109                                  ordered_extent->file_offset +
3110                                  ordered_extent->len - 1,
3111                                  clear_bits,
3112                                  (clear_bits & EXTENT_LOCKED) ? 1 : 0,
3113                                  0, &cached_state);
3114         }
3115
3116         if (trans)
3117                 btrfs_end_transaction(trans);
3118
3119         if (ret || truncated) {
3120                 u64 start, end;
3121
3122                 if (truncated)
3123                         start = ordered_extent->file_offset + logical_len;
3124                 else
3125                         start = ordered_extent->file_offset;
3126                 end = ordered_extent->file_offset + ordered_extent->len - 1;
3127                 clear_extent_uptodate(io_tree, start, end, NULL);
3128
3129                 /* Drop the cache for the part of the extent we didn't write. */
3130                 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3131
3132                 /*
3133                  * If the ordered extent had an IOERR or something else went
3134                  * wrong we need to return the space for this ordered extent
3135                  * back to the allocator.  We only free the extent in the
3136                  * truncated case if we didn't write out the extent at all.
3137                  */
3138                 if ((ret || !logical_len) &&
3139                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
3140                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
3141                         btrfs_free_reserved_extent(fs_info,
3142                                                    ordered_extent->start,
3143                                                    ordered_extent->disk_len, 1);
3144         }
3145
3146
3147         /*
3148          * This needs to be done to make sure anybody waiting knows we are done
3149          * updating everything for this ordered extent.
3150          */
3151         btrfs_remove_ordered_extent(inode, ordered_extent);
3152
3153         /* for snapshot-aware defrag */
3154         if (new) {
3155                 if (ret) {
3156                         free_sa_defrag_extent(new);
3157                         atomic_dec(&fs_info->defrag_running);
3158                 } else {
3159                         relink_file_extents(new);
3160                 }
3161         }
3162
3163         /* once for us */
3164         btrfs_put_ordered_extent(ordered_extent);
3165         /* once for the tree */
3166         btrfs_put_ordered_extent(ordered_extent);
3167
3168         /* Try to release some metadata so we don't get an OOM but don't wait */
3169         btrfs_btree_balance_dirty_nodelay(fs_info);
3170
3171         return ret;
3172 }
3173
3174 static void finish_ordered_fn(struct btrfs_work *work)
3175 {
3176         struct btrfs_ordered_extent *ordered_extent;
3177         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
3178         btrfs_finish_ordered_io(ordered_extent);
3179 }
3180
3181 static void btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
3182                                 struct extent_state *state, int uptodate)
3183 {
3184         struct inode *inode = page->mapping->host;
3185         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3186         struct btrfs_ordered_extent *ordered_extent = NULL;
3187         struct btrfs_workqueue *wq;
3188         btrfs_work_func_t func;
3189
3190         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
3191
3192         ClearPagePrivate2(page);
3193         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
3194                                             end - start + 1, uptodate))
3195                 return;
3196
3197         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
3198                 wq = fs_info->endio_freespace_worker;
3199                 func = btrfs_freespace_write_helper;
3200         } else {
3201                 wq = fs_info->endio_write_workers;
3202                 func = btrfs_endio_write_helper;
3203         }
3204
3205         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
3206                         NULL);
3207         btrfs_queue_work(wq, &ordered_extent->work);
3208 }
3209
3210 static int __readpage_endio_check(struct inode *inode,
3211                                   struct btrfs_io_bio *io_bio,
3212                                   int icsum, struct page *page,
3213                                   int pgoff, u64 start, size_t len)
3214 {
3215         char *kaddr;
3216         u32 csum_expected;
3217         u32 csum = ~(u32)0;
3218
3219         csum_expected = *(((u32 *)io_bio->csum) + icsum);
3220
3221         kaddr = kmap_atomic(page);
3222         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
3223         btrfs_csum_final(csum, (u8 *)&csum);
3224         if (csum != csum_expected)
3225                 goto zeroit;
3226
3227         kunmap_atomic(kaddr);
3228         return 0;
3229 zeroit:
3230         btrfs_print_data_csum_error(BTRFS_I(inode), start, csum, csum_expected,
3231                                     io_bio->mirror_num);
3232         memset(kaddr + pgoff, 1, len);
3233         flush_dcache_page(page);
3234         kunmap_atomic(kaddr);
3235         return -EIO;
3236 }
3237
3238 /*
3239  * when reads are done, we need to check csums to verify the data is correct
3240  * if there's a match, we allow the bio to finish.  If not, the code in
3241  * extent_io.c will try to find good copies for us.
3242  */
3243 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
3244                                       u64 phy_offset, struct page *page,
3245                                       u64 start, u64 end, int mirror)
3246 {
3247         size_t offset = start - page_offset(page);
3248         struct inode *inode = page->mapping->host;
3249         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3250         struct btrfs_root *root = BTRFS_I(inode)->root;
3251
3252         if (PageChecked(page)) {
3253                 ClearPageChecked(page);
3254                 return 0;
3255         }
3256
3257         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
3258                 return 0;
3259
3260         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
3261             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
3262                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM);
3263                 return 0;
3264         }
3265
3266         phy_offset >>= inode->i_sb->s_blocksize_bits;
3267         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
3268                                       start, (size_t)(end - start + 1));
3269 }
3270
3271 /*
3272  * btrfs_add_delayed_iput - perform a delayed iput on @inode
3273  *
3274  * @inode: The inode we want to perform iput on
3275  *
3276  * This function uses the generic vfs_inode::i_count to track whether we should
3277  * just decrement it (in case it's > 1) or if this is the last iput then link
3278  * the inode to the delayed iput machinery. Delayed iputs are processed at
3279  * transaction commit time/superblock commit/cleaner kthread.
3280  */
3281 void btrfs_add_delayed_iput(struct inode *inode)
3282 {
3283         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3284         struct btrfs_inode *binode = BTRFS_I(inode);
3285
3286         if (atomic_add_unless(&inode->i_count, -1, 1))
3287                 return;
3288
3289         spin_lock(&fs_info->delayed_iput_lock);
3290         ASSERT(list_empty(&binode->delayed_iput));
3291         list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs);
3292         spin_unlock(&fs_info->delayed_iput_lock);
3293 }
3294
3295 void btrfs_run_delayed_iputs(struct btrfs_fs_info *fs_info)
3296 {
3297
3298         spin_lock(&fs_info->delayed_iput_lock);
3299         while (!list_empty(&fs_info->delayed_iputs)) {
3300                 struct btrfs_inode *inode;
3301
3302                 inode = list_first_entry(&fs_info->delayed_iputs,
3303                                 struct btrfs_inode, delayed_iput);
3304                 list_del_init(&inode->delayed_iput);
3305                 spin_unlock(&fs_info->delayed_iput_lock);
3306                 iput(&inode->vfs_inode);
3307                 spin_lock(&fs_info->delayed_iput_lock);
3308         }
3309         spin_unlock(&fs_info->delayed_iput_lock);
3310 }
3311
3312 /*
3313  * This creates an orphan entry for the given inode in case something goes wrong
3314  * in the middle of an unlink.
3315  */
3316 int btrfs_orphan_add(struct btrfs_trans_handle *trans,
3317                      struct btrfs_inode *inode)
3318 {
3319         int ret;
3320
3321         ret = btrfs_insert_orphan_item(trans, inode->root, btrfs_ino(inode));
3322         if (ret && ret != -EEXIST) {
3323                 btrfs_abort_transaction(trans, ret);
3324                 return ret;
3325         }
3326
3327         return 0;
3328 }
3329
3330 /*
3331  * We have done the delete so we can go ahead and remove the orphan item for
3332  * this particular inode.
3333  */
3334 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3335                             struct btrfs_inode *inode)
3336 {
3337         return btrfs_del_orphan_item(trans, inode->root, btrfs_ino(inode));
3338 }
3339
3340 /*
3341  * this cleans up any orphans that may be left on the list from the last use
3342  * of this root.
3343  */
3344 int btrfs_orphan_cleanup(struct btrfs_root *root)
3345 {
3346         struct btrfs_fs_info *fs_info = root->fs_info;
3347         struct btrfs_path *path;
3348         struct extent_buffer *leaf;
3349         struct btrfs_key key, found_key;
3350         struct btrfs_trans_handle *trans;
3351         struct inode *inode;
3352         u64 last_objectid = 0;
3353         int ret = 0, nr_unlink = 0;
3354
3355         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3356                 return 0;
3357
3358         path = btrfs_alloc_path();
3359         if (!path) {
3360                 ret = -ENOMEM;
3361                 goto out;
3362         }
3363         path->reada = READA_BACK;
3364
3365         key.objectid = BTRFS_ORPHAN_OBJECTID;
3366         key.type = BTRFS_ORPHAN_ITEM_KEY;
3367         key.offset = (u64)-1;
3368
3369         while (1) {
3370                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3371                 if (ret < 0)
3372                         goto out;
3373
3374                 /*
3375                  * if ret == 0 means we found what we were searching for, which
3376                  * is weird, but possible, so only screw with path if we didn't
3377                  * find the key and see if we have stuff that matches
3378                  */
3379                 if (ret > 0) {
3380                         ret = 0;
3381                         if (path->slots[0] == 0)
3382                                 break;
3383                         path->slots[0]--;
3384                 }
3385
3386                 /* pull out the item */
3387                 leaf = path->nodes[0];
3388                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3389
3390                 /* make sure the item matches what we want */
3391                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3392                         break;
3393                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3394                         break;
3395
3396                 /* release the path since we're done with it */
3397                 btrfs_release_path(path);
3398
3399                 /*
3400                  * this is where we are basically btrfs_lookup, without the
3401                  * crossing root thing.  we store the inode number in the
3402                  * offset of the orphan item.
3403                  */
3404
3405                 if (found_key.offset == last_objectid) {
3406                         btrfs_err(fs_info,
3407                                   "Error removing orphan entry, stopping orphan cleanup");
3408                         ret = -EINVAL;
3409                         goto out;
3410                 }
3411
3412                 last_objectid = found_key.offset;
3413
3414                 found_key.objectid = found_key.offset;
3415                 found_key.type = BTRFS_INODE_ITEM_KEY;
3416                 found_key.offset = 0;
3417                 inode = btrfs_iget(fs_info->sb, &found_key, root, NULL);
3418                 ret = PTR_ERR_OR_ZERO(inode);
3419                 if (ret && ret != -ENOENT)
3420                         goto out;
3421
3422                 if (ret == -ENOENT && root == fs_info->tree_root) {
3423                         struct btrfs_root *dead_root;
3424                         struct btrfs_fs_info *fs_info = root->fs_info;
3425                         int is_dead_root = 0;
3426
3427                         /*
3428                          * this is an orphan in the tree root. Currently these
3429                          * could come from 2 sources:
3430                          *  a) a snapshot deletion in progress
3431                          *  b) a free space cache inode
3432                          * We need to distinguish those two, as the snapshot
3433                          * orphan must not get deleted.
3434                          * find_dead_roots already ran before us, so if this
3435                          * is a snapshot deletion, we should find the root
3436                          * in the dead_roots list
3437                          */
3438                         spin_lock(&fs_info->trans_lock);
3439                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3440                                             root_list) {
3441                                 if (dead_root->root_key.objectid ==
3442                                     found_key.objectid) {
3443                                         is_dead_root = 1;
3444                                         break;
3445                                 }
3446                         }
3447                         spin_unlock(&fs_info->trans_lock);
3448                         if (is_dead_root) {
3449                                 /* prevent this orphan from being found again */
3450                                 key.offset = found_key.objectid - 1;
3451                                 continue;
3452                         }
3453
3454                 }
3455
3456                 /*
3457                  * If we have an inode with links, there are a couple of
3458                  * possibilities. Old kernels (before v3.12) used to create an
3459                  * orphan item for truncate indicating that there were possibly
3460                  * extent items past i_size that needed to be deleted. In v3.12,
3461                  * truncate was changed to update i_size in sync with the extent
3462                  * items, but the (useless) orphan item was still created. Since
3463                  * v4.18, we don't create the orphan item for truncate at all.
3464                  *
3465                  * So, this item could mean that we need to do a truncate, but
3466                  * only if this filesystem was last used on a pre-v3.12 kernel
3467                  * and was not cleanly unmounted. The odds of that are quite
3468                  * slim, and it's a pain to do the truncate now, so just delete
3469                  * the orphan item.
3470                  *
3471                  * It's also possible that this orphan item was supposed to be
3472                  * deleted but wasn't. The inode number may have been reused,
3473                  * but either way, we can delete the orphan item.
3474                  */
3475                 if (ret == -ENOENT || inode->i_nlink) {
3476                         if (!ret)
3477                                 iput(inode);
3478                         trans = btrfs_start_transaction(root, 1);
3479                         if (IS_ERR(trans)) {
3480                                 ret = PTR_ERR(trans);
3481                                 goto out;
3482                         }
3483                         btrfs_debug(fs_info, "auto deleting %Lu",
3484                                     found_key.objectid);
3485                         ret = btrfs_del_orphan_item(trans, root,
3486                                                     found_key.objectid);
3487                         btrfs_end_transaction(trans);
3488                         if (ret)
3489                                 goto out;
3490                         continue;
3491                 }
3492
3493                 nr_unlink++;
3494
3495                 /* this will do delete_inode and everything for us */
3496                 iput(inode);
3497                 if (ret)
3498                         goto out;
3499         }
3500         /* release the path since we're done with it */
3501         btrfs_release_path(path);
3502
3503         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3504
3505         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3506                 trans = btrfs_join_transaction(root);
3507                 if (!IS_ERR(trans))
3508                         btrfs_end_transaction(trans);
3509         }
3510
3511         if (nr_unlink)
3512                 btrfs_debug(fs_info, "unlinked %d orphans", nr_unlink);
3513
3514 out:
3515         if (ret)
3516                 btrfs_err(fs_info, "could not do orphan cleanup %d", ret);
3517         btrfs_free_path(path);
3518         return ret;
3519 }
3520
3521 /*
3522  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3523  * don't find any xattrs, we know there can't be any acls.
3524  *
3525  * slot is the slot the inode is in, objectid is the objectid of the inode
3526  */
3527 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3528                                           int slot, u64 objectid,
3529                                           int *first_xattr_slot)
3530 {
3531         u32 nritems = btrfs_header_nritems(leaf);
3532         struct btrfs_key found_key;
3533         static u64 xattr_access = 0;
3534         static u64 xattr_default = 0;
3535         int scanned = 0;
3536
3537         if (!xattr_access) {
3538                 xattr_access = btrfs_name_hash(XATTR_NAME_POSIX_ACL_ACCESS,
3539                                         strlen(XATTR_NAME_POSIX_ACL_ACCESS));
3540                 xattr_default = btrfs_name_hash(XATTR_NAME_POSIX_ACL_DEFAULT,
3541                                         strlen(XATTR_NAME_POSIX_ACL_DEFAULT));
3542         }
3543
3544         slot++;
3545         *first_xattr_slot = -1;
3546         while (slot < nritems) {
3547                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3548
3549                 /* we found a different objectid, there must not be acls */
3550                 if (found_key.objectid != objectid)
3551                         return 0;
3552
3553                 /* we found an xattr, assume we've got an acl */
3554                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3555                         if (*first_xattr_slot == -1)
3556                                 *first_xattr_slot = slot;
3557                         if (found_key.offset == xattr_access ||
3558                             found_key.offset == xattr_default)
3559                                 return 1;
3560                 }
3561
3562                 /*
3563                  * we found a key greater than an xattr key, there can't
3564                  * be any acls later on
3565                  */
3566                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3567                         return 0;
3568
3569                 slot++;
3570                 scanned++;
3571
3572                 /*
3573                  * it goes inode, inode backrefs, xattrs, extents,
3574                  * so if there are a ton of hard links to an inode there can
3575                  * be a lot of backrefs.  Don't waste time searching too hard,
3576                  * this is just an optimization
3577                  */
3578                 if (scanned >= 8)
3579                         break;
3580         }
3581         /* we hit the end of the leaf before we found an xattr or
3582          * something larger than an xattr.  We have to assume the inode
3583          * has acls
3584          */
3585         if (*first_xattr_slot == -1)
3586                 *first_xattr_slot = slot;
3587         return 1;
3588 }
3589
3590 /*
3591  * read an inode from the btree into the in-memory inode
3592  */
3593 static int btrfs_read_locked_inode(struct inode *inode)
3594 {
3595         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3596         struct btrfs_path *path;
3597         struct extent_buffer *leaf;
3598         struct btrfs_inode_item *inode_item;
3599         struct btrfs_root *root = BTRFS_I(inode)->root;
3600         struct btrfs_key location;
3601         unsigned long ptr;
3602         int maybe_acls;
3603         u32 rdev;
3604         int ret;
3605         bool filled = false;
3606         int first_xattr_slot;
3607
3608         ret = btrfs_fill_inode(inode, &rdev);
3609         if (!ret)
3610                 filled = true;
3611
3612         path = btrfs_alloc_path();
3613         if (!path) {
3614                 ret = -ENOMEM;
3615                 goto make_bad;
3616         }
3617
3618         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3619
3620         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3621         if (ret) {
3622                 if (ret > 0)
3623                         ret = -ENOENT;
3624                 goto make_bad;
3625         }
3626
3627         leaf = path->nodes[0];
3628
3629         if (filled)
3630                 goto cache_index;
3631
3632         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3633                                     struct btrfs_inode_item);
3634         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3635         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3636         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3637         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3638         btrfs_i_size_write(BTRFS_I(inode), btrfs_inode_size(leaf, inode_item));
3639
3640         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3641         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3642
3643         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3644         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3645
3646         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3647         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3648
3649         BTRFS_I(inode)->i_otime.tv_sec =
3650                 btrfs_timespec_sec(leaf, &inode_item->otime);
3651         BTRFS_I(inode)->i_otime.tv_nsec =
3652                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3653
3654         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3655         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3656         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3657
3658         inode_set_iversion_queried(inode,
3659                                    btrfs_inode_sequence(leaf, inode_item));
3660         inode->i_generation = BTRFS_I(inode)->generation;
3661         inode->i_rdev = 0;
3662         rdev = btrfs_inode_rdev(leaf, inode_item);
3663
3664         BTRFS_I(inode)->index_cnt = (u64)-1;
3665         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3666
3667 cache_index:
3668         /*
3669          * If we were modified in the current generation and evicted from memory
3670          * and then re-read we need to do a full sync since we don't have any
3671          * idea about which extents were modified before we were evicted from
3672          * cache.
3673          *
3674          * This is required for both inode re-read from disk and delayed inode
3675          * in delayed_nodes_tree.
3676          */
3677         if (BTRFS_I(inode)->last_trans == fs_info->generation)
3678                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3679                         &BTRFS_I(inode)->runtime_flags);
3680
3681         /*
3682          * We don't persist the id of the transaction where an unlink operation
3683          * against the inode was last made. So here we assume the inode might
3684          * have been evicted, and therefore the exact value of last_unlink_trans
3685          * lost, and set it to last_trans to avoid metadata inconsistencies
3686          * between the inode and its parent if the inode is fsync'ed and the log
3687          * replayed. For example, in the scenario:
3688          *
3689          * touch mydir/foo
3690          * ln mydir/foo mydir/bar
3691          * sync
3692          * unlink mydir/bar
3693          * echo 2 > /proc/sys/vm/drop_caches   # evicts inode
3694          * xfs_io -c fsync mydir/foo
3695          * <power failure>
3696          * mount fs, triggers fsync log replay
3697          *
3698          * We must make sure that when we fsync our inode foo we also log its
3699          * parent inode, otherwise after log replay the parent still has the
3700          * dentry with the "bar" name but our inode foo has a link count of 1
3701          * and doesn't have an inode ref with the name "bar" anymore.
3702          *
3703          * Setting last_unlink_trans to last_trans is a pessimistic approach,
3704          * but it guarantees correctness at the expense of occasional full
3705          * transaction commits on fsync if our inode is a directory, or if our
3706          * inode is not a directory, logging its parent unnecessarily.
3707          */
3708         BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans;
3709
3710         path->slots[0]++;
3711         if (inode->i_nlink != 1 ||
3712             path->slots[0] >= btrfs_header_nritems(leaf))
3713                 goto cache_acl;
3714
3715         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3716         if (location.objectid != btrfs_ino(BTRFS_I(inode)))
3717                 goto cache_acl;
3718
3719         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3720         if (location.type == BTRFS_INODE_REF_KEY) {
3721                 struct btrfs_inode_ref *ref;
3722
3723                 ref = (struct btrfs_inode_ref *)ptr;
3724                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3725         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3726                 struct btrfs_inode_extref *extref;
3727
3728                 extref = (struct btrfs_inode_extref *)ptr;
3729                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3730                                                                      extref);
3731         }
3732 cache_acl:
3733         /*
3734          * try to precache a NULL acl entry for files that don't have
3735          * any xattrs or acls
3736          */
3737         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3738                         btrfs_ino(BTRFS_I(inode)), &first_xattr_slot);
3739         if (first_xattr_slot != -1) {
3740                 path->slots[0] = first_xattr_slot;
3741                 ret = btrfs_load_inode_props(inode, path);
3742                 if (ret)
3743                         btrfs_err(fs_info,
3744                                   "error loading props for ino %llu (root %llu): %d",
3745                                   btrfs_ino(BTRFS_I(inode)),
3746                                   root->root_key.objectid, ret);
3747         }
3748         btrfs_free_path(path);
3749
3750         if (!maybe_acls)
3751                 cache_no_acl(inode);
3752
3753         switch (inode->i_mode & S_IFMT) {
3754         case S_IFREG:
3755                 inode->i_mapping->a_ops = &btrfs_aops;
3756                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3757                 inode->i_fop = &btrfs_file_operations;
3758                 inode->i_op = &btrfs_file_inode_operations;
3759                 break;
3760         case S_IFDIR:
3761                 inode->i_fop = &btrfs_dir_file_operations;
3762                 inode->i_op = &btrfs_dir_inode_operations;
3763                 break;
3764         case S_IFLNK:
3765                 inode->i_op = &btrfs_symlink_inode_operations;
3766                 inode_nohighmem(inode);
3767                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3768                 break;
3769         default:
3770                 inode->i_op = &btrfs_special_inode_operations;
3771                 init_special_inode(inode, inode->i_mode, rdev);
3772                 break;
3773         }
3774
3775         btrfs_sync_inode_flags_to_i_flags(inode);
3776         return 0;
3777
3778 make_bad:
3779         btrfs_free_path(path);
3780         make_bad_inode(inode);
3781         return ret;
3782 }
3783
3784 /*
3785  * given a leaf and an inode, copy the inode fields into the leaf
3786  */
3787 static void fill_inode_item(struct btrfs_trans_handle *trans,
3788                             struct extent_buffer *leaf,
3789                             struct btrfs_inode_item *item,
3790                             struct inode *inode)
3791 {
3792         struct btrfs_map_token token;
3793
3794         btrfs_init_map_token(&token);
3795
3796         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3797         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3798         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3799                                    &token);
3800         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3801         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3802
3803         btrfs_set_token_timespec_sec(leaf, &item->atime,
3804                                      inode->i_atime.tv_sec, &token);
3805         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3806                                       inode->i_atime.tv_nsec, &token);
3807
3808         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3809                                      inode->i_mtime.tv_sec, &token);
3810         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3811                                       inode->i_mtime.tv_nsec, &token);
3812
3813         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3814                                      inode->i_ctime.tv_sec, &token);
3815         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3816                                       inode->i_ctime.tv_nsec, &token);
3817
3818         btrfs_set_token_timespec_sec(leaf, &item->otime,
3819                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3820         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3821                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3822
3823         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3824                                      &token);
3825         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3826                                          &token);
3827         btrfs_set_token_inode_sequence(leaf, item, inode_peek_iversion(inode),
3828                                        &token);
3829         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3830         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3831         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3832         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3833 }
3834
3835 /*
3836  * copy everything in the in-memory inode into the btree.
3837  */
3838 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3839                                 struct btrfs_root *root, struct inode *inode)
3840 {
3841         struct btrfs_inode_item *inode_item;
3842         struct btrfs_path *path;
3843         struct extent_buffer *leaf;
3844         int ret;
3845
3846         path = btrfs_alloc_path();
3847         if (!path)
3848                 return -ENOMEM;
3849
3850         path->leave_spinning = 1;
3851         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3852                                  1);
3853         if (ret) {
3854                 if (ret > 0)
3855                         ret = -ENOENT;
3856                 goto failed;
3857         }
3858
3859         leaf = path->nodes[0];
3860         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3861                                     struct btrfs_inode_item);
3862
3863         fill_inode_item(trans, leaf, inode_item, inode);
3864         btrfs_mark_buffer_dirty(leaf);
3865         btrfs_set_inode_last_trans(trans, inode);
3866         ret = 0;
3867 failed:
3868         btrfs_free_path(path);
3869         return ret;
3870 }
3871
3872 /*
3873  * copy everything in the in-memory inode into the btree.
3874  */
3875 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3876                                 struct btrfs_root *root, struct inode *inode)
3877 {
3878         struct btrfs_fs_info *fs_info = root->fs_info;
3879         int ret;
3880
3881         /*
3882          * If the inode is a free space inode, we can deadlock during commit
3883          * if we put it into the delayed code.
3884          *
3885          * The data relocation inode should also be directly updated
3886          * without delay
3887          */
3888         if (!btrfs_is_free_space_inode(BTRFS_I(inode))
3889             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3890             && !test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) {
3891                 btrfs_update_root_times(trans, root);
3892
3893                 ret = btrfs_delayed_update_inode(trans, root, inode);
3894                 if (!ret)
3895                         btrfs_set_inode_last_trans(trans, inode);
3896                 return ret;
3897         }
3898
3899         return btrfs_update_inode_item(trans, root, inode);
3900 }
3901
3902 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3903                                          struct btrfs_root *root,
3904                                          struct inode *inode)
3905 {
3906         int ret;
3907
3908         ret = btrfs_update_inode(trans, root, inode);
3909         if (ret == -ENOSPC)
3910                 return btrfs_update_inode_item(trans, root, inode);
3911         return ret;
3912 }
3913
3914 /*
3915  * unlink helper that gets used here in inode.c and in the tree logging
3916  * recovery code.  It remove a link in a directory with a given name, and
3917  * also drops the back refs in the inode to the directory
3918  */
3919 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3920                                 struct btrfs_root *root,
3921                                 struct btrfs_inode *dir,
3922                                 struct btrfs_inode *inode,
3923                                 const char *name, int name_len)
3924 {
3925         struct btrfs_fs_info *fs_info = root->fs_info;
3926         struct btrfs_path *path;
3927         int ret = 0;
3928         struct extent_buffer *leaf;
3929         struct btrfs_dir_item *di;
3930         struct btrfs_key key;
3931         u64 index;
3932         u64 ino = btrfs_ino(inode);
3933         u64 dir_ino = btrfs_ino(dir);
3934
3935         path = btrfs_alloc_path();
3936         if (!path) {
3937                 ret = -ENOMEM;
3938                 goto out;
3939         }
3940
3941         path->leave_spinning = 1;
3942         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3943                                     name, name_len, -1);
3944         if (IS_ERR(di)) {
3945                 ret = PTR_ERR(di);
3946                 goto err;
3947         }
3948         if (!di) {
3949                 ret = -ENOENT;
3950                 goto err;
3951         }
3952         leaf = path->nodes[0];
3953         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3954         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3955         if (ret)
3956                 goto err;
3957         btrfs_release_path(path);
3958
3959         /*
3960          * If we don't have dir index, we have to get it by looking up
3961          * the inode ref, since we get the inode ref, remove it directly,
3962          * it is unnecessary to do delayed deletion.
3963          *
3964          * But if we have dir index, needn't search inode ref to get it.
3965          * Since the inode ref is close to the inode item, it is better
3966          * that we delay to delete it, and just do this deletion when
3967          * we update the inode item.
3968          */
3969         if (inode->dir_index) {
3970                 ret = btrfs_delayed_delete_inode_ref(inode);
3971                 if (!ret) {
3972                         index = inode->dir_index;
3973                         goto skip_backref;
3974                 }
3975         }
3976
3977         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3978                                   dir_ino, &index);
3979         if (ret) {
3980                 btrfs_info(fs_info,
3981                         "failed to delete reference to %.*s, inode %llu parent %llu",
3982                         name_len, name, ino, dir_ino);
3983                 btrfs_abort_transaction(trans, ret);
3984                 goto err;
3985         }
3986 skip_backref:
3987         ret = btrfs_delete_delayed_dir_index(trans, fs_info, dir, index);
3988         if (ret) {
3989                 btrfs_abort_transaction(trans, ret);
3990                 goto err;
3991         }
3992
3993         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len, inode,
3994                         dir_ino);
3995         if (ret != 0 && ret != -ENOENT) {
3996                 btrfs_abort_transaction(trans, ret);
3997                 goto err;
3998         }
3999
4000         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len, dir,
4001                         index);
4002         if (ret == -ENOENT)
4003                 ret = 0;
4004         else if (ret)
4005                 btrfs_abort_transaction(trans, ret);
4006 err:
4007         btrfs_free_path(path);
4008         if (ret)
4009                 goto out;
4010
4011         btrfs_i_size_write(dir, dir->vfs_inode.i_size - name_len * 2);
4012         inode_inc_iversion(&inode->vfs_inode);
4013         inode_inc_iversion(&dir->vfs_inode);
4014         inode->vfs_inode.i_ctime = dir->vfs_inode.i_mtime =
4015                 dir->vfs_inode.i_ctime = current_time(&inode->vfs_inode);
4016         ret = btrfs_update_inode(trans, root, &dir->vfs_inode);
4017 out:
4018         return ret;
4019 }
4020
4021 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
4022                        struct btrfs_root *root,
4023                        struct btrfs_inode *dir, struct btrfs_inode *inode,
4024                        const char *name, int name_len)
4025 {
4026         int ret;
4027         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
4028         if (!ret) {
4029                 drop_nlink(&inode->vfs_inode);
4030                 ret = btrfs_update_inode(trans, root, &inode->vfs_inode);
4031         }
4032         return ret;
4033 }
4034
4035 /*
4036  * helper to start transaction for unlink and rmdir.
4037  *
4038  * unlink and rmdir are special in btrfs, they do not always free space, so
4039  * if we cannot make our reservations the normal way try and see if there is
4040  * plenty of slack room in the global reserve to migrate, otherwise we cannot
4041  * allow the unlink to occur.
4042  */
4043 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
4044 {
4045         struct btrfs_root *root = BTRFS_I(dir)->root;
4046
4047         /*
4048          * 1 for the possible orphan item
4049          * 1 for the dir item
4050          * 1 for the dir index
4051          * 1 for the inode ref
4052          * 1 for the inode
4053          */
4054         return btrfs_start_transaction_fallback_global_rsv(root, 5, 5);
4055 }
4056
4057 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
4058 {
4059         struct btrfs_root *root = BTRFS_I(dir)->root;
4060         struct btrfs_trans_handle *trans;
4061         struct inode *inode = d_inode(dentry);
4062         int ret;
4063
4064         trans = __unlink_start_trans(dir);
4065         if (IS_ERR(trans))
4066                 return PTR_ERR(trans);
4067
4068         btrfs_record_unlink_dir(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
4069                         0);
4070
4071         ret = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
4072                         BTRFS_I(d_inode(dentry)), dentry->d_name.name,
4073                         dentry->d_name.len);
4074         if (ret)
4075                 goto out;
4076
4077         if (inode->i_nlink == 0) {
4078                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
4079                 if (ret)
4080                         goto out;
4081         }
4082
4083 out:
4084         btrfs_end_transaction(trans);
4085         btrfs_btree_balance_dirty(root->fs_info);
4086         return ret;
4087 }
4088
4089 static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
4090                         struct btrfs_root *root,
4091                         struct inode *dir, u64 objectid,
4092                         const char *name, int name_len)
4093 {
4094         struct btrfs_fs_info *fs_info = root->fs_info;
4095         struct btrfs_path *path;
4096         struct extent_buffer *leaf;
4097         struct btrfs_dir_item *di;
4098         struct btrfs_key key;
4099         u64 index;
4100         int ret;
4101         u64 dir_ino = btrfs_ino(BTRFS_I(dir));
4102
4103         path = btrfs_alloc_path();
4104         if (!path)
4105                 return -ENOMEM;
4106
4107         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
4108                                    name, name_len, -1);
4109         if (IS_ERR_OR_NULL(di)) {
4110                 if (!di)
4111                         ret = -ENOENT;
4112                 else
4113                         ret = PTR_ERR(di);
4114                 goto out;
4115         }
4116
4117         leaf = path->nodes[0];
4118         btrfs_dir_item_key_to_cpu(leaf, di, &key);
4119         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
4120         ret = btrfs_delete_one_dir_name(trans, root, path, di);
4121         if (ret) {
4122                 btrfs_abort_transaction(trans, ret);
4123                 goto out;
4124         }
4125         btrfs_release_path(path);
4126
4127         ret = btrfs_del_root_ref(trans, fs_info, objectid,
4128                                  root->root_key.objectid, dir_ino,
4129                                  &index, name, name_len);
4130         if (ret < 0) {
4131                 if (ret != -ENOENT) {
4132                         btrfs_abort_transaction(trans, ret);
4133                         goto out;
4134                 }
4135                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4136                                                  name, name_len);
4137                 if (IS_ERR_OR_NULL(di)) {
4138                         if (!di)
4139                                 ret = -ENOENT;
4140                         else
4141                                 ret = PTR_ERR(di);
4142                         btrfs_abort_transaction(trans, ret);
4143                         goto out;
4144                 }
4145
4146                 leaf = path->nodes[0];
4147                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4148                 btrfs_release_path(path);
4149                 index = key.offset;
4150         }
4151         btrfs_release_path(path);
4152
4153         ret = btrfs_delete_delayed_dir_index(trans, fs_info, BTRFS_I(dir), index);
4154         if (ret) {
4155                 btrfs_abort_transaction(trans, ret);
4156                 goto out;
4157         }
4158
4159         btrfs_i_size_write(BTRFS_I(dir), dir->i_size - name_len * 2);
4160         inode_inc_iversion(dir);
4161         dir->i_mtime = dir->i_ctime = current_time(dir);
4162         ret = btrfs_update_inode_fallback(trans, root, dir);
4163         if (ret)
4164                 btrfs_abort_transaction(trans, ret);
4165 out:
4166         btrfs_free_path(path);
4167         return ret;
4168 }
4169
4170 /*
4171  * Helper to check if the subvolume references other subvolumes or if it's
4172  * default.
4173  */
4174 static noinline int may_destroy_subvol(struct btrfs_root *root)
4175 {
4176         struct btrfs_fs_info *fs_info = root->fs_info;
4177         struct btrfs_path *path;
4178         struct btrfs_dir_item *di;
4179         struct btrfs_key key;
4180         u64 dir_id;
4181         int ret;
4182
4183         path = btrfs_alloc_path();
4184         if (!path)
4185                 return -ENOMEM;
4186
4187         /* Make sure this root isn't set as the default subvol */
4188         dir_id = btrfs_super_root_dir(fs_info->super_copy);
4189         di = btrfs_lookup_dir_item(NULL, fs_info->tree_root, path,
4190                                    dir_id, "default", 7, 0);
4191         if (di && !IS_ERR(di)) {
4192                 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
4193                 if (key.objectid == root->root_key.objectid) {
4194                         ret = -EPERM;
4195                         btrfs_err(fs_info,
4196                                   "deleting default subvolume %llu is not allowed",
4197                                   key.objectid);
4198                         goto out;
4199                 }
4200                 btrfs_release_path(path);
4201         }
4202
4203         key.objectid = root->root_key.objectid;
4204         key.type = BTRFS_ROOT_REF_KEY;
4205         key.offset = (u64)-1;
4206
4207         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
4208         if (ret < 0)
4209                 goto out;
4210         BUG_ON(ret == 0);
4211
4212         ret = 0;
4213         if (path->slots[0] > 0) {
4214                 path->slots[0]--;
4215                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
4216                 if (key.objectid == root->root_key.objectid &&
4217                     key.type == BTRFS_ROOT_REF_KEY)
4218                         ret = -ENOTEMPTY;
4219         }
4220 out:
4221         btrfs_free_path(path);
4222         return ret;
4223 }
4224
4225 /* Delete all dentries for inodes belonging to the root */
4226 static void btrfs_prune_dentries(struct btrfs_root *root)
4227 {
4228         struct btrfs_fs_info *fs_info = root->fs_info;
4229         struct rb_node *node;
4230         struct rb_node *prev;
4231         struct btrfs_inode *entry;
4232         struct inode *inode;
4233         u64 objectid = 0;
4234
4235         if (!test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
4236                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4237
4238         spin_lock(&root->inode_lock);
4239 again:
4240         node = root->inode_tree.rb_node;
4241         prev = NULL;
4242         while (node) {
4243                 prev = node;
4244                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4245
4246                 if (objectid < btrfs_ino(BTRFS_I(&entry->vfs_inode)))
4247                         node = node->rb_left;
4248                 else if (objectid > btrfs_ino(BTRFS_I(&entry->vfs_inode)))
4249                         node = node->rb_right;
4250                 else
4251                         break;
4252         }
4253         if (!node) {
4254                 while (prev) {
4255                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4256                         if (objectid <= btrfs_ino(BTRFS_I(&entry->vfs_inode))) {
4257                                 node = prev;
4258                                 break;
4259                         }
4260                         prev = rb_next(prev);
4261                 }
4262         }
4263         while (node) {
4264                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4265                 objectid = btrfs_ino(BTRFS_I(&entry->vfs_inode)) + 1;
4266                 inode = igrab(&entry->vfs_inode);
4267                 if (inode) {
4268                         spin_unlock(&root->inode_lock);
4269                         if (atomic_read(&inode->i_count) > 1)
4270                                 d_prune_aliases(inode);
4271                         /*
4272                          * btrfs_drop_inode will have it removed from the inode
4273                          * cache when its usage count hits zero.
4274                          */
4275                         iput(inode);
4276                         cond_resched();
4277                         spin_lock(&root->inode_lock);
4278                         goto again;
4279                 }
4280
4281                 if (cond_resched_lock(&root->inode_lock))
4282                         goto again;
4283
4284                 node = rb_next(node);
4285         }
4286         spin_unlock(&root->inode_lock);
4287 }
4288
4289 int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry)
4290 {
4291         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
4292         struct btrfs_root *root = BTRFS_I(dir)->root;
4293         struct inode *inode = d_inode(dentry);
4294         struct btrfs_root *dest = BTRFS_I(inode)->root;
4295         struct btrfs_trans_handle *trans;
4296         struct btrfs_block_rsv block_rsv;
4297         u64 root_flags;
4298         int ret;
4299         int err;
4300
4301         /*
4302          * Don't allow to delete a subvolume with send in progress. This is
4303          * inside the inode lock so the error handling that has to drop the bit
4304          * again is not run concurrently.
4305          */
4306         spin_lock(&dest->root_item_lock);
4307         root_flags = btrfs_root_flags(&dest->root_item);
4308         if (dest->send_in_progress == 0) {
4309                 btrfs_set_root_flags(&dest->root_item,
4310                                 root_flags | BTRFS_ROOT_SUBVOL_DEAD);
4311                 spin_unlock(&dest->root_item_lock);
4312         } else {
4313                 spin_unlock(&dest->root_item_lock);
4314                 btrfs_warn(fs_info,
4315                            "attempt to delete subvolume %llu during send",
4316                            dest->root_key.objectid);
4317                 return -EPERM;
4318         }
4319
4320         down_write(&fs_info->subvol_sem);
4321
4322         err = may_destroy_subvol(dest);
4323         if (err)
4324                 goto out_up_write;
4325
4326         btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
4327         /*
4328          * One for dir inode,
4329          * two for dir entries,
4330          * two for root ref/backref.
4331          */
4332         err = btrfs_subvolume_reserve_metadata(root, &block_rsv, 5, true);
4333         if (err)
4334                 goto out_up_write;
4335
4336         trans = btrfs_start_transaction(root, 0);
4337         if (IS_ERR(trans)) {
4338                 err = PTR_ERR(trans);
4339                 goto out_release;
4340         }
4341         trans->block_rsv = &block_rsv;
4342         trans->bytes_reserved = block_rsv.size;
4343
4344         btrfs_record_snapshot_destroy(trans, BTRFS_I(dir));
4345
4346         ret = btrfs_unlink_subvol(trans, root, dir,
4347                                 dest->root_key.objectid,
4348                                 dentry->d_name.name,
4349                                 dentry->d_name.len);
4350         if (ret) {
4351                 err = ret;
4352                 btrfs_abort_transaction(trans, ret);
4353                 goto out_end_trans;
4354         }
4355
4356         btrfs_record_root_in_trans(trans, dest);
4357
4358         memset(&dest->root_item.drop_progress, 0,
4359                 sizeof(dest->root_item.drop_progress));
4360         dest->root_item.drop_level = 0;
4361         btrfs_set_root_refs(&dest->root_item, 0);
4362
4363         if (!test_and_set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &dest->state)) {
4364                 ret = btrfs_insert_orphan_item(trans,
4365                                         fs_info->tree_root,
4366                                         dest->root_key.objectid);
4367                 if (ret) {
4368                         btrfs_abort_transaction(trans, ret);
4369                         err = ret;
4370                         goto out_end_trans;
4371                 }
4372         }
4373
4374         ret = btrfs_uuid_tree_remove(trans, dest->root_item.uuid,
4375                                   BTRFS_UUID_KEY_SUBVOL,
4376                                   dest->root_key.objectid);
4377         if (ret && ret != -ENOENT) {
4378                 btrfs_abort_transaction(trans, ret);
4379                 err = ret;
4380                 goto out_end_trans;
4381         }
4382         if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) {
4383                 ret = btrfs_uuid_tree_remove(trans,
4384                                           dest->root_item.received_uuid,
4385                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4386                                           dest->root_key.objectid);
4387                 if (ret && ret != -ENOENT) {
4388                         btrfs_abort_transaction(trans, ret);
4389                         err = ret;
4390                         goto out_end_trans;
4391                 }
4392         }
4393
4394 out_end_trans:
4395         trans->block_rsv = NULL;
4396         trans->bytes_reserved = 0;
4397         ret = btrfs_end_transaction(trans);
4398         if (ret && !err)
4399                 err = ret;
4400         inode->i_flags |= S_DEAD;
4401 out_release:
4402         btrfs_subvolume_release_metadata(fs_info, &block_rsv);
4403 out_up_write:
4404         up_write(&fs_info->subvol_sem);
4405         if (err) {
4406                 spin_lock(&dest->root_item_lock);
4407                 root_flags = btrfs_root_flags(&dest->root_item);
4408                 btrfs_set_root_flags(&dest->root_item,
4409                                 root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);
4410                 spin_unlock(&dest->root_item_lock);
4411         } else {
4412                 d_invalidate(dentry);
4413                 btrfs_prune_dentries(dest);
4414                 ASSERT(dest->send_in_progress == 0);
4415
4416                 /* the last ref */
4417                 if (dest->ino_cache_inode) {
4418                         iput(dest->ino_cache_inode);
4419                         dest->ino_cache_inode = NULL;
4420                 }
4421         }
4422
4423         return err;
4424 }
4425
4426 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4427 {
4428         struct inode *inode = d_inode(dentry);
4429         int err = 0;
4430         struct btrfs_root *root = BTRFS_I(dir)->root;
4431         struct btrfs_trans_handle *trans;
4432         u64 last_unlink_trans;
4433
4434         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4435                 return -ENOTEMPTY;
4436         if (btrfs_ino(BTRFS_I(inode)) == BTRFS_FIRST_FREE_OBJECTID)
4437                 return btrfs_delete_subvolume(dir, dentry);
4438
4439         trans = __unlink_start_trans(dir);
4440         if (IS_ERR(trans))
4441                 return PTR_ERR(trans);
4442
4443         if (unlikely(btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4444                 err = btrfs_unlink_subvol(trans, root, dir,
4445                                           BTRFS_I(inode)->location.objectid,
4446                                           dentry->d_name.name,
4447                                           dentry->d_name.len);
4448                 goto out;
4449         }
4450
4451         err = btrfs_orphan_add(trans, BTRFS_I(inode));
4452         if (err)
4453                 goto out;
4454
4455         last_unlink_trans = BTRFS_I(inode)->last_unlink_trans;
4456
4457         /* now the directory is empty */
4458         err = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
4459                         BTRFS_I(d_inode(dentry)), dentry->d_name.name,
4460                         dentry->d_name.len);
4461         if (!err) {
4462                 btrfs_i_size_write(BTRFS_I(inode), 0);
4463                 /*
4464                  * Propagate the last_unlink_trans value of the deleted dir to
4465                  * its parent directory. This is to prevent an unrecoverable
4466                  * log tree in the case we do something like this:
4467                  * 1) create dir foo
4468                  * 2) create snapshot under dir foo
4469                  * 3) delete the snapshot
4470                  * 4) rmdir foo
4471                  * 5) mkdir foo
4472                  * 6) fsync foo or some file inside foo
4473                  */
4474                 if (last_unlink_trans >= trans->transid)
4475                         BTRFS_I(dir)->last_unlink_trans = last_unlink_trans;
4476         }
4477 out:
4478         btrfs_end_transaction(trans);
4479         btrfs_btree_balance_dirty(root->fs_info);
4480
4481         return err;
4482 }
4483
4484 static int truncate_space_check(struct btrfs_trans_handle *trans,
4485                                 struct btrfs_root *root,
4486                                 u64 bytes_deleted)
4487 {
4488         struct btrfs_fs_info *fs_info = root->fs_info;
4489         int ret;
4490
4491         /*
4492          * This is only used to apply pressure to the enospc system, we don't
4493          * intend to use this reservation at all.
4494          */
4495         bytes_deleted = btrfs_csum_bytes_to_leaves(fs_info, bytes_deleted);
4496         bytes_deleted *= fs_info->nodesize;
4497         ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv,
4498                                   bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
4499         if (!ret) {
4500                 trace_btrfs_space_reservation(fs_info, "transaction",
4501                                               trans->transid,
4502                                               bytes_deleted, 1);
4503                 trans->bytes_reserved += bytes_deleted;
4504         }
4505         return ret;
4506
4507 }
4508
4509 /*
4510  * Return this if we need to call truncate_block for the last bit of the
4511  * truncate.
4512  */
4513 #define NEED_TRUNCATE_BLOCK 1
4514
4515 /*
4516  * this can truncate away extent items, csum items and directory items.
4517  * It starts at a high offset and removes keys until it can't find
4518  * any higher than new_size
4519  *
4520  * csum items that cross the new i_size are truncated to the new size
4521  * as well.
4522  *
4523  * min_type is the minimum key type to truncate down to.  If set to 0, this
4524  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4525  */
4526 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4527                                struct btrfs_root *root,
4528                                struct inode *inode,
4529                                u64 new_size, u32 min_type)
4530 {
4531         struct btrfs_fs_info *fs_info = root->fs_info;
4532         struct btrfs_path *path;
4533         struct extent_buffer *leaf;
4534         struct btrfs_file_extent_item *fi;
4535         struct btrfs_key key;
4536         struct btrfs_key found_key;
4537         u64 extent_start = 0;
4538         u64 extent_num_bytes = 0;
4539         u64 extent_offset = 0;
4540         u64 item_end = 0;
4541         u64 last_size = new_size;
4542         u32 found_type = (u8)-1;
4543         int found_extent;
4544         int del_item;
4545         int pending_del_nr = 0;
4546         int pending_del_slot = 0;
4547         int extent_type = -1;
4548         int ret;
4549         u64 ino = btrfs_ino(BTRFS_I(inode));
4550         u64 bytes_deleted = 0;
4551         bool be_nice = false;
4552         bool should_throttle = false;
4553         bool should_end = false;
4554
4555         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4556
4557         /*
4558          * for non-free space inodes and ref cows, we want to back off from
4559          * time to time
4560          */
4561         if (!btrfs_is_free_space_inode(BTRFS_I(inode)) &&
4562             test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4563                 be_nice = true;
4564
4565         path = btrfs_alloc_path();
4566         if (!path)
4567                 return -ENOMEM;
4568         path->reada = READA_BACK;
4569
4570         /*
4571          * We want to drop from the next block forward in case this new size is
4572          * not block aligned since we will be keeping the last block of the
4573          * extent just the way it is.
4574          */
4575         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4576             root == fs_info->tree_root)
4577                 btrfs_drop_extent_cache(BTRFS_I(inode), ALIGN(new_size,
4578                                         fs_info->sectorsize),
4579                                         (u64)-1, 0);
4580
4581         /*
4582          * This function is also used to drop the items in the log tree before
4583          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4584          * it is used to drop the loged items. So we shouldn't kill the delayed
4585          * items.
4586          */
4587         if (min_type == 0 && root == BTRFS_I(inode)->root)
4588                 btrfs_kill_delayed_inode_items(BTRFS_I(inode));
4589
4590         key.objectid = ino;
4591         key.offset = (u64)-1;
4592         key.type = (u8)-1;
4593
4594 search_again:
4595         /*
4596          * with a 16K leaf size and 128MB extents, you can actually queue
4597          * up a huge file in a single leaf.  Most of the time that
4598          * bytes_deleted is > 0, it will be huge by the time we get here
4599          */
4600         if (be_nice && bytes_deleted > SZ_32M &&
4601             btrfs_should_end_transaction(trans)) {
4602                 ret = -EAGAIN;
4603                 goto out;
4604         }
4605
4606         path->leave_spinning = 1;
4607         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4608         if (ret < 0)
4609                 goto out;
4610
4611         if (ret > 0) {
4612                 ret = 0;
4613                 /* there are no items in the tree for us to truncate, we're
4614                  * done
4615                  */
4616                 if (path->slots[0] == 0)
4617                         goto out;
4618                 path->slots[0]--;
4619         }
4620
4621         while (1) {
4622                 fi = NULL;
4623                 leaf = path->nodes[0];
4624                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4625                 found_type = found_key.type;
4626
4627                 if (found_key.objectid != ino)
4628                         break;
4629
4630                 if (found_type < min_type)
4631                         break;
4632
4633                 item_end = found_key.offset;
4634                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4635                         fi = btrfs_item_ptr(leaf, path->slots[0],
4636                                             struct btrfs_file_extent_item);
4637                         extent_type = btrfs_file_extent_type(leaf, fi);
4638                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4639                                 item_end +=
4640                                     btrfs_file_extent_num_bytes(leaf, fi);
4641
4642                                 trace_btrfs_truncate_show_fi_regular(
4643                                         BTRFS_I(inode), leaf, fi,
4644                                         found_key.offset);
4645                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4646                                 item_end += btrfs_file_extent_inline_len(leaf,
4647                                                          path->slots[0], fi);
4648
4649                                 trace_btrfs_truncate_show_fi_inline(
4650                                         BTRFS_I(inode), leaf, fi, path->slots[0],
4651                                         found_key.offset);
4652                         }
4653                         item_end--;
4654                 }
4655                 if (found_type > min_type) {
4656                         del_item = 1;
4657                 } else {
4658                         if (item_end < new_size)
4659                                 break;
4660                         if (found_key.offset >= new_size)
4661                                 del_item = 1;
4662                         else
4663                                 del_item = 0;
4664                 }
4665                 found_extent = 0;
4666                 /* FIXME, shrink the extent if the ref count is only 1 */
4667                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4668                         goto delete;
4669
4670                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4671                         u64 num_dec;
4672                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4673                         if (!del_item) {
4674                                 u64 orig_num_bytes =
4675                                         btrfs_file_extent_num_bytes(leaf, fi);
4676                                 extent_num_bytes = ALIGN(new_size -
4677                                                 found_key.offset,
4678                                                 fs_info->sectorsize);
4679                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4680                                                          extent_num_bytes);
4681                                 num_dec = (orig_num_bytes -
4682                                            extent_num_bytes);
4683                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4684                                              &root->state) &&
4685                                     extent_start != 0)
4686                                         inode_sub_bytes(inode, num_dec);
4687                                 btrfs_mark_buffer_dirty(leaf);
4688                         } else {
4689                                 extent_num_bytes =
4690                                         btrfs_file_extent_disk_num_bytes(leaf,
4691                                                                          fi);
4692                                 extent_offset = found_key.offset -
4693                                         btrfs_file_extent_offset(leaf, fi);
4694
4695                                 /* FIXME blocksize != 4096 */
4696                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4697                                 if (extent_start != 0) {
4698                                         found_extent = 1;
4699                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4700                                                      &root->state))
4701                                                 inode_sub_bytes(inode, num_dec);
4702                                 }
4703                         }
4704                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4705                         /*
4706                          * we can't truncate inline items that have had
4707                          * special encodings
4708                          */
4709                         if (!del_item &&
4710                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4711                             btrfs_file_extent_other_encoding(leaf, fi) == 0 &&
4712                             btrfs_file_extent_compression(leaf, fi) == 0) {
4713                                 u32 size = (u32)(new_size - found_key.offset);
4714
4715                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4716                                 size = btrfs_file_extent_calc_inline_size(size);
4717                                 btrfs_truncate_item(root->fs_info, path, size, 1);
4718                         } else if (!del_item) {
4719                                 /*
4720                                  * We have to bail so the last_size is set to
4721                                  * just before this extent.
4722                                  */
4723                                 ret = NEED_TRUNCATE_BLOCK;
4724                                 break;
4725                         }
4726
4727                         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4728                                 inode_sub_bytes(inode, item_end + 1 - new_size);
4729                 }
4730 delete:
4731                 if (del_item)
4732                         last_size = found_key.offset;
4733                 else
4734                         last_size = new_size;
4735                 if (del_item) {
4736                         if (!pending_del_nr) {
4737                                 /* no pending yet, add ourselves */
4738                                 pending_del_slot = path->slots[0];
4739                                 pending_del_nr = 1;
4740                         } else if (pending_del_nr &&
4741                                    path->slots[0] + 1 == pending_del_slot) {
4742                                 /* hop on the pending chunk */
4743                                 pending_del_nr++;
4744                                 pending_del_slot = path->slots[0];
4745                         } else {
4746                                 BUG();
4747                         }
4748                 } else {
4749                         break;
4750                 }
4751                 should_throttle = false;
4752
4753                 if (found_extent &&
4754                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4755                      root == fs_info->tree_root)) {
4756                         btrfs_set_path_blocking(path);
4757                         bytes_deleted += extent_num_bytes;
4758                         ret = btrfs_free_extent(trans, root, extent_start,
4759                                                 extent_num_bytes, 0,
4760                                                 btrfs_header_owner(leaf),
4761                                                 ino, extent_offset);
4762                         if (ret) {
4763                                 btrfs_abort_transaction(trans, ret);
4764                                 break;
4765                         }
4766                         if (btrfs_should_throttle_delayed_refs(trans, fs_info))
4767                                 btrfs_async_run_delayed_refs(fs_info,
4768                                         trans->delayed_ref_updates * 2,
4769                                         trans->transid, 0);
4770                         if (be_nice) {
4771                                 if (truncate_space_check(trans, root,
4772                                                          extent_num_bytes)) {
4773                                         should_end = true;
4774                                 }
4775                                 if (btrfs_should_throttle_delayed_refs(trans,
4776                                                                        fs_info))
4777                                         should_throttle = true;
4778                         }
4779                 }
4780
4781                 if (found_type == BTRFS_INODE_ITEM_KEY)
4782                         break;
4783
4784                 if (path->slots[0] == 0 ||
4785                     path->slots[0] != pending_del_slot ||
4786                     should_throttle || should_end) {
4787                         if (pending_del_nr) {
4788                                 ret = btrfs_del_items(trans, root, path,
4789                                                 pending_del_slot,
4790                                                 pending_del_nr);
4791                                 if (ret) {
4792                                         btrfs_abort_transaction(trans, ret);
4793                                         break;
4794                                 }
4795                                 pending_del_nr = 0;
4796                         }
4797                         btrfs_release_path(path);
4798                         if (should_throttle) {
4799                                 unsigned long updates = trans->delayed_ref_updates;
4800                                 if (updates) {
4801                                         trans->delayed_ref_updates = 0;
4802                                         ret = btrfs_run_delayed_refs(trans,
4803                                                                    updates * 2);
4804                                         if (ret)
4805                                                 break;
4806                                 }
4807                         }
4808                         /*
4809                          * if we failed to refill our space rsv, bail out
4810                          * and let the transaction restart
4811                          */
4812                         if (should_end) {
4813                                 ret = -EAGAIN;
4814                                 break;
4815                         }
4816                         goto search_again;
4817                 } else {
4818                         path->slots[0]--;
4819                 }
4820         }
4821 out:
4822         if (ret >= 0 && pending_del_nr) {
4823                 int err;
4824
4825                 err = btrfs_del_items(trans, root, path, pending_del_slot,
4826                                       pending_del_nr);
4827                 if (err) {
4828                         btrfs_abort_transaction(trans, err);
4829                         ret = err;
4830                 }
4831         }
4832         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4833                 ASSERT(last_size >= new_size);
4834                 if (!ret && last_size > new_size)
4835                         last_size = new_size;
4836                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4837         }
4838
4839         btrfs_free_path(path);
4840
4841         if (be_nice && bytes_deleted > SZ_32M && (ret >= 0 || ret == -EAGAIN)) {
4842                 unsigned long updates = trans->delayed_ref_updates;
4843                 int err;
4844
4845                 if (updates) {
4846                         trans->delayed_ref_updates = 0;
4847                         err = btrfs_run_delayed_refs(trans, updates * 2);
4848                         if (err)
4849                                 ret = err;
4850                 }
4851         }
4852         return ret;
4853 }
4854
4855 /*
4856  * btrfs_truncate_block - read, zero a chunk and write a block
4857  * @inode - inode that we're zeroing
4858  * @from - the offset to start zeroing
4859  * @len - the length to zero, 0 to zero the entire range respective to the
4860  *      offset
4861  * @front - zero up to the offset instead of from the offset on
4862  *
4863  * This will find the block for the "from" offset and cow the block and zero the
4864  * part we want to zero.  This is used with truncate and hole punching.
4865  */
4866 int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
4867                         int front)
4868 {
4869         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4870         struct address_space *mapping = inode->i_mapping;
4871         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4872         struct btrfs_ordered_extent *ordered;
4873         struct extent_state *cached_state = NULL;
4874         struct extent_changeset *data_reserved = NULL;
4875         char *kaddr;
4876         u32 blocksize = fs_info->sectorsize;
4877         pgoff_t index = from >> PAGE_SHIFT;
4878         unsigned offset = from & (blocksize - 1);
4879         struct page *page;
4880         gfp_t mask = btrfs_alloc_write_mask(mapping);
4881         int ret = 0;
4882         u64 block_start;
4883         u64 block_end;
4884
4885         if (IS_ALIGNED(offset, blocksize) &&
4886             (!len || IS_ALIGNED(len, blocksize)))
4887                 goto out;
4888
4889         block_start = round_down(from, blocksize);
4890         block_end = block_start + blocksize - 1;
4891
4892         ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
4893                                            block_start, blocksize);
4894         if (ret)
4895                 goto out;
4896
4897 again:
4898         page = find_or_create_page(mapping, index, mask);
4899         if (!page) {
4900                 btrfs_delalloc_release_space(inode, data_reserved,
4901                                              block_start, blocksize, true);
4902                 btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, true);
4903                 ret = -ENOMEM;
4904                 goto out;
4905         }
4906
4907         if (!PageUptodate(page)) {
4908                 ret = btrfs_readpage(NULL, page);
4909                 lock_page(page);
4910                 if (page->mapping != mapping) {
4911                         unlock_page(page);
4912                         put_page(page);
4913                         goto again;
4914                 }
4915                 if (!PageUptodate(page)) {
4916                         ret = -EIO;
4917                         goto out_unlock;
4918                 }
4919         }
4920         wait_on_page_writeback(page);
4921
4922         lock_extent_bits(io_tree, block_start, block_end, &cached_state);
4923         set_page_extent_mapped(page);
4924
4925         ordered = btrfs_lookup_ordered_extent(inode, block_start);
4926         if (ordered) {
4927                 unlock_extent_cached(io_tree, block_start, block_end,
4928                                      &cached_state);
4929                 unlock_page(page);
4930                 put_page(page);
4931                 btrfs_start_ordered_extent(inode, ordered, 1);
4932                 btrfs_put_ordered_extent(ordered);
4933                 goto again;
4934         }
4935
4936         clear_extent_bit(&BTRFS_I(inode)->io_tree, block_start, block_end,
4937                           EXTENT_DIRTY | EXTENT_DELALLOC |
4938                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4939                           0, 0, &cached_state);
4940
4941         ret = btrfs_set_extent_delalloc(inode, block_start, block_end, 0,
4942                                         &cached_state, 0);
4943         if (ret) {
4944                 unlock_extent_cached(io_tree, block_start, block_end,
4945                                      &cached_state);
4946                 goto out_unlock;
4947         }
4948
4949         if (offset != blocksize) {
4950                 if (!len)
4951                         len = blocksize - offset;
4952                 kaddr = kmap(page);
4953                 if (front)
4954                         memset(kaddr + (block_start - page_offset(page)),
4955                                 0, offset);
4956                 else
4957                         memset(kaddr + (block_start - page_offset(page)) +  offset,
4958                                 0, len);
4959                 flush_dcache_page(page);
4960                 kunmap(page);
4961         }
4962         ClearPageChecked(page);
4963         set_page_dirty(page);
4964         unlock_extent_cached(io_tree, block_start, block_end, &cached_state);
4965
4966 out_unlock:
4967         if (ret)
4968                 btrfs_delalloc_release_space(inode, data_reserved, block_start,
4969                                              blocksize, true);
4970         btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, (ret != 0));
4971         unlock_page(page);
4972         put_page(page);
4973 out:
4974         extent_changeset_free(data_reserved);
4975         return ret;
4976 }
4977
4978 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4979                              u64 offset, u64 len)
4980 {
4981         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4982         struct btrfs_trans_handle *trans;
4983         int ret;
4984
4985         /*
4986          * Still need to make sure the inode looks like it's been updated so
4987          * that any holes get logged if we fsync.
4988          */
4989         if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
4990                 BTRFS_I(inode)->last_trans = fs_info->generation;
4991                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4992                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4993                 return 0;
4994         }
4995
4996         /*
4997          * 1 - for the one we're dropping
4998          * 1 - for the one we're adding
4999          * 1 - for updating the inode.
5000          */
5001         trans = btrfs_start_transaction(root, 3);
5002         if (IS_ERR(trans))
5003                 return PTR_ERR(trans);
5004
5005         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
5006         if (ret) {
5007                 btrfs_abort_transaction(trans, ret);
5008                 btrfs_end_transaction(trans);
5009                 return ret;
5010         }
5011
5012         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(BTRFS_I(inode)),
5013                         offset, 0, 0, len, 0, len, 0, 0, 0);
5014         if (ret)
5015                 btrfs_abort_transaction(trans, ret);
5016         else
5017                 btrfs_update_inode(trans, root, inode);
5018         btrfs_end_transaction(trans);
5019         return ret;
5020 }
5021
5022 /*
5023  * This function puts in dummy file extents for the area we're creating a hole
5024  * for.  So if we are truncating this file to a larger size we need to insert
5025  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
5026  * the range between oldsize and size
5027  */
5028 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
5029 {
5030         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5031         struct btrfs_root *root = BTRFS_I(inode)->root;
5032         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5033         struct extent_map *em = NULL;
5034         struct extent_state *cached_state = NULL;
5035         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5036         u64 hole_start = ALIGN(oldsize, fs_info->sectorsize);
5037         u64 block_end = ALIGN(size, fs_info->sectorsize);
5038         u64 last_byte;
5039         u64 cur_offset;
5040         u64 hole_size;
5041         int err = 0;
5042
5043         /*
5044          * If our size started in the middle of a block we need to zero out the
5045          * rest of the block before we expand the i_size, otherwise we could
5046          * expose stale data.
5047          */
5048         err = btrfs_truncate_block(inode, oldsize, 0, 0);
5049         if (err)
5050                 return err;
5051
5052         if (size <= hole_start)
5053                 return 0;
5054
5055         while (1) {
5056                 struct btrfs_ordered_extent *ordered;
5057
5058                 lock_extent_bits(io_tree, hole_start, block_end - 1,
5059                                  &cached_state);
5060                 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), hole_start,
5061                                                      block_end - hole_start);
5062                 if (!ordered)
5063                         break;
5064                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
5065                                      &cached_state);
5066                 btrfs_start_ordered_extent(inode, ordered, 1);
5067                 btrfs_put_ordered_extent(ordered);
5068         }
5069
5070         cur_offset = hole_start;
5071         while (1) {
5072                 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
5073                                 block_end - cur_offset, 0);
5074                 if (IS_ERR(em)) {
5075                         err = PTR_ERR(em);
5076                         em = NULL;
5077                         break;
5078                 }
5079                 last_byte = min(extent_map_end(em), block_end);
5080                 last_byte = ALIGN(last_byte, fs_info->sectorsize);
5081                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
5082                         struct extent_map *hole_em;
5083                         hole_size = last_byte - cur_offset;
5084
5085                         err = maybe_insert_hole(root, inode, cur_offset,
5086                                                 hole_size);
5087                         if (err)
5088                                 break;
5089                         btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
5090                                                 cur_offset + hole_size - 1, 0);
5091                         hole_em = alloc_extent_map();
5092                         if (!hole_em) {
5093                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
5094                                         &BTRFS_I(inode)->runtime_flags);
5095                                 goto next;
5096                         }
5097                         hole_em->start = cur_offset;
5098                         hole_em->len = hole_size;
5099                         hole_em->orig_start = cur_offset;
5100
5101                         hole_em->block_start = EXTENT_MAP_HOLE;
5102                         hole_em->block_len = 0;
5103                         hole_em->orig_block_len = 0;
5104                         hole_em->ram_bytes = hole_size;
5105                         hole_em->bdev = fs_info->fs_devices->latest_bdev;
5106                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
5107                         hole_em->generation = fs_info->generation;
5108
5109                         while (1) {
5110                                 write_lock(&em_tree->lock);
5111                                 err = add_extent_mapping(em_tree, hole_em, 1);
5112                                 write_unlock(&em_tree->lock);
5113                                 if (err != -EEXIST)
5114                                         break;
5115                                 btrfs_drop_extent_cache(BTRFS_I(inode),
5116                                                         cur_offset,
5117                                                         cur_offset +
5118                                                         hole_size - 1, 0);
5119                         }
5120                         free_extent_map(hole_em);
5121                 }
5122 next:
5123                 free_extent_map(em);
5124                 em = NULL;
5125                 cur_offset = last_byte;
5126                 if (cur_offset >= block_end)
5127                         break;
5128         }
5129         free_extent_map(em);
5130         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state);
5131         return err;
5132 }
5133
5134 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
5135 {
5136         struct btrfs_root *root = BTRFS_I(inode)->root;
5137         struct btrfs_trans_handle *trans;
5138         loff_t oldsize = i_size_read(inode);
5139         loff_t newsize = attr->ia_size;
5140         int mask = attr->ia_valid;
5141         int ret;
5142
5143         /*
5144          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
5145          * special case where we need to update the times despite not having
5146          * these flags set.  For all other operations the VFS set these flags
5147          * explicitly if it wants a timestamp update.
5148          */
5149         if (newsize != oldsize) {
5150                 inode_inc_iversion(inode);
5151                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
5152                         inode->i_ctime = inode->i_mtime =
5153                                 current_time(inode);
5154         }
5155
5156         if (newsize > oldsize) {
5157                 /*
5158                  * Don't do an expanding truncate while snapshotting is ongoing.
5159                  * This is to ensure the snapshot captures a fully consistent
5160                  * state of this file - if the snapshot captures this expanding
5161                  * truncation, it must capture all writes that happened before
5162                  * this truncation.
5163                  */
5164                 btrfs_wait_for_snapshot_creation(root);
5165                 ret = btrfs_cont_expand(inode, oldsize, newsize);
5166                 if (ret) {
5167                         btrfs_end_write_no_snapshotting(root);
5168                         return ret;
5169                 }
5170
5171                 trans = btrfs_start_transaction(root, 1);
5172                 if (IS_ERR(trans)) {
5173                         btrfs_end_write_no_snapshotting(root);
5174                         return PTR_ERR(trans);
5175                 }
5176
5177                 i_size_write(inode, newsize);
5178                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
5179                 pagecache_isize_extended(inode, oldsize, newsize);
5180                 ret = btrfs_update_inode(trans, root, inode);
5181                 btrfs_end_write_no_snapshotting(root);
5182                 btrfs_end_transaction(trans);
5183         } else {
5184
5185                 /*
5186                  * We're truncating a file that used to have good data down to
5187                  * zero. Make sure it gets into the ordered flush list so that
5188                  * any new writes get down to disk quickly.
5189                  */
5190                 if (newsize == 0)
5191                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
5192                                 &BTRFS_I(inode)->runtime_flags);
5193
5194                 truncate_setsize(inode, newsize);
5195
5196                 /* Disable nonlocked read DIO to avoid the end less truncate */
5197                 btrfs_inode_block_unlocked_dio(BTRFS_I(inode));
5198                 inode_dio_wait(inode);
5199                 btrfs_inode_resume_unlocked_dio(BTRFS_I(inode));
5200
5201                 ret = btrfs_truncate(inode, newsize == oldsize);
5202                 if (ret && inode->i_nlink) {
5203                         int err;
5204
5205                         /*
5206                          * Truncate failed, so fix up the in-memory size. We
5207                          * adjusted disk_i_size down as we removed extents, so
5208                          * wait for disk_i_size to be stable and then update the
5209                          * in-memory size to match.
5210                          */
5211                         err = btrfs_wait_ordered_range(inode, 0, (u64)-1);
5212                         if (err)
5213                                 return err;
5214                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
5215                 }
5216         }
5217
5218         return ret;
5219 }
5220
5221 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
5222 {
5223         struct inode *inode = d_inode(dentry);
5224         struct btrfs_root *root = BTRFS_I(inode)->root;
5225         int err;
5226
5227         if (btrfs_root_readonly(root))
5228                 return -EROFS;
5229
5230         err = setattr_prepare(dentry, attr);
5231         if (err)
5232                 return err;
5233
5234         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
5235                 err = btrfs_setsize(inode, attr);
5236                 if (err)
5237                         return err;
5238         }
5239
5240         if (attr->ia_valid) {
5241                 setattr_copy(inode, attr);
5242                 inode_inc_iversion(inode);
5243                 err = btrfs_dirty_inode(inode);
5244
5245                 if (!err && attr->ia_valid & ATTR_MODE)
5246                         err = posix_acl_chmod(inode, inode->i_mode);
5247         }
5248
5249         return err;
5250 }
5251
5252 /*
5253  * While truncating the inode pages during eviction, we get the VFS calling
5254  * btrfs_invalidatepage() against each page of the inode. This is slow because
5255  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
5256  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
5257  * extent_state structures over and over, wasting lots of time.
5258  *
5259  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
5260  * those expensive operations on a per page basis and do only the ordered io
5261  * finishing, while we release here the extent_map and extent_state structures,
5262  * without the excessive merging and splitting.
5263  */
5264 static void evict_inode_truncate_pages(struct inode *inode)
5265 {
5266         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5267         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
5268         struct rb_node *node;
5269
5270         ASSERT(inode->i_state & I_FREEING);
5271         truncate_inode_pages_final(&inode->i_data);
5272
5273         write_lock(&map_tree->lock);
5274         while (!RB_EMPTY_ROOT(&map_tree->map)) {
5275                 struct extent_map *em;
5276
5277                 node = rb_first(&map_tree->map);
5278                 em = rb_entry(node, struct extent_map, rb_node);
5279                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
5280                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
5281                 remove_extent_mapping(map_tree, em);
5282                 free_extent_map(em);
5283                 if (need_resched()) {
5284                         write_unlock(&map_tree->lock);
5285                         cond_resched();
5286                         write_lock(&map_tree->lock);
5287                 }
5288         }
5289         write_unlock(&map_tree->lock);
5290
5291         /*
5292          * Keep looping until we have no more ranges in the io tree.
5293          * We can have ongoing bios started by readpages (called from readahead)
5294          * that have their endio callback (extent_io.c:end_bio_extent_readpage)
5295          * still in progress (unlocked the pages in the bio but did not yet
5296          * unlocked the ranges in the io tree). Therefore this means some
5297          * ranges can still be locked and eviction started because before
5298          * submitting those bios, which are executed by a separate task (work
5299          * queue kthread), inode references (inode->i_count) were not taken
5300          * (which would be dropped in the end io callback of each bio).
5301          * Therefore here we effectively end up waiting for those bios and
5302          * anyone else holding locked ranges without having bumped the inode's
5303          * reference count - if we don't do it, when they access the inode's
5304          * io_tree to unlock a range it may be too late, leading to an
5305          * use-after-free issue.
5306          */
5307         spin_lock(&io_tree->lock);
5308         while (!RB_EMPTY_ROOT(&io_tree->state)) {
5309                 struct extent_state *state;
5310                 struct extent_state *cached_state = NULL;
5311                 u64 start;
5312                 u64 end;
5313
5314                 node = rb_first(&io_tree->state);
5315                 state = rb_entry(node, struct extent_state, rb_node);
5316                 start = state->start;
5317                 end = state->end;
5318                 spin_unlock(&io_tree->lock);
5319
5320                 lock_extent_bits(io_tree, start, end, &cached_state);
5321
5322                 /*
5323                  * If still has DELALLOC flag, the extent didn't reach disk,
5324                  * and its reserved space won't be freed by delayed_ref.
5325                  * So we need to free its reserved space here.
5326                  * (Refer to comment in btrfs_invalidatepage, case 2)
5327                  *
5328                  * Note, end is the bytenr of last byte, so we need + 1 here.
5329                  */
5330                 if (state->state & EXTENT_DELALLOC)
5331                         btrfs_qgroup_free_data(inode, NULL, start, end - start + 1);
5332
5333                 clear_extent_bit(io_tree, start, end,
5334                                  EXTENT_LOCKED | EXTENT_DIRTY |
5335                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
5336                                  EXTENT_DEFRAG, 1, 1, &cached_state);
5337
5338                 cond_resched();
5339                 spin_lock(&io_tree->lock);
5340         }
5341         spin_unlock(&io_tree->lock);
5342 }
5343
5344 static struct btrfs_trans_handle *evict_refill_and_join(struct btrfs_root *root,
5345                                                         struct btrfs_block_rsv *rsv,
5346                                                         u64 min_size)
5347 {
5348         struct btrfs_fs_info *fs_info = root->fs_info;
5349         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5350         int failures = 0;
5351
5352         for (;;) {
5353                 struct btrfs_trans_handle *trans;
5354                 int ret;
5355
5356                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
5357                                              BTRFS_RESERVE_FLUSH_LIMIT);
5358
5359                 if (ret && ++failures > 2) {
5360                         btrfs_warn(fs_info,
5361                                    "could not allocate space for a delete; will truncate on mount");
5362                         return ERR_PTR(-ENOSPC);
5363                 }
5364
5365                 trans = btrfs_join_transaction(root);
5366                 if (IS_ERR(trans) || !ret)
5367                         return trans;
5368
5369                 /*
5370                  * Try to steal from the global reserve if there is space for
5371                  * it.
5372                  */
5373                 if (!btrfs_check_space_for_delayed_refs(trans, fs_info) &&
5374                     !btrfs_block_rsv_migrate(global_rsv, rsv, min_size, 0))
5375                         return trans;
5376
5377                 /* If not, commit and try again. */
5378                 ret = btrfs_commit_transaction(trans);
5379                 if (ret)
5380                         return ERR_PTR(ret);
5381         }
5382 }
5383
5384 void btrfs_evict_inode(struct inode *inode)
5385 {
5386         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5387         struct btrfs_trans_handle *trans;
5388         struct btrfs_root *root = BTRFS_I(inode)->root;
5389         struct btrfs_block_rsv *rsv;
5390         u64 min_size;
5391         int ret;
5392
5393         trace_btrfs_inode_evict(inode);
5394
5395         if (!root) {
5396                 clear_inode(inode);
5397                 return;
5398         }
5399
5400         min_size = btrfs_calc_trunc_metadata_size(fs_info, 1);
5401
5402         evict_inode_truncate_pages(inode);
5403
5404         if (inode->i_nlink &&
5405             ((btrfs_root_refs(&root->root_item) != 0 &&
5406               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
5407              btrfs_is_free_space_inode(BTRFS_I(inode))))
5408                 goto no_delete;
5409
5410         if (is_bad_inode(inode))
5411                 goto no_delete;
5412         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
5413         if (!special_file(inode->i_mode))
5414                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
5415
5416         btrfs_free_io_failure_record(BTRFS_I(inode), 0, (u64)-1);
5417
5418         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
5419                 goto no_delete;
5420
5421         if (inode->i_nlink > 0) {
5422                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
5423                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
5424                 goto no_delete;
5425         }
5426
5427         ret = btrfs_commit_inode_delayed_inode(BTRFS_I(inode));
5428         if (ret)
5429                 goto no_delete;
5430
5431         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
5432         if (!rsv)
5433                 goto no_delete;
5434         rsv->size = min_size;
5435         rsv->failfast = 1;
5436
5437         btrfs_i_size_write(BTRFS_I(inode), 0);
5438
5439         while (1) {
5440                 trans = evict_refill_and_join(root, rsv, min_size);
5441                 if (IS_ERR(trans))
5442                         goto free_rsv;
5443
5444                 trans->block_rsv = rsv;
5445
5446                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
5447                 trans->block_rsv = &fs_info->trans_block_rsv;
5448                 btrfs_end_transaction(trans);
5449                 btrfs_btree_balance_dirty(fs_info);
5450                 if (ret && ret != -ENOSPC && ret != -EAGAIN)
5451                         goto free_rsv;
5452                 else if (!ret)
5453                         break;
5454         }
5455
5456         /*
5457          * Errors here aren't a big deal, it just means we leave orphan items in
5458          * the tree. They will be cleaned up on the next mount. If the inode
5459          * number gets reused, cleanup deletes the orphan item without doing
5460          * anything, and unlink reuses the existing orphan item.
5461          *
5462          * If it turns out that we are dropping too many of these, we might want
5463          * to add a mechanism for retrying these after a commit.
5464          */
5465         trans = evict_refill_and_join(root, rsv, min_size);
5466         if (!IS_ERR(trans)) {
5467                 trans->block_rsv = rsv;
5468                 btrfs_orphan_del(trans, BTRFS_I(inode));
5469                 trans->block_rsv = &fs_info->trans_block_rsv;
5470                 btrfs_end_transaction(trans);
5471         }
5472
5473         if (!(root == fs_info->tree_root ||
5474               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
5475                 btrfs_return_ino(root, btrfs_ino(BTRFS_I(inode)));
5476
5477 free_rsv:
5478         btrfs_free_block_rsv(fs_info, rsv);
5479 no_delete:
5480         /*
5481          * If we didn't successfully delete, the orphan item will still be in
5482          * the tree and we'll retry on the next mount. Again, we might also want
5483          * to retry these periodically in the future.
5484          */
5485         btrfs_remove_delayed_node(BTRFS_I(inode));
5486         clear_inode(inode);
5487 }
5488
5489 /*
5490  * this returns the key found in the dir entry in the location pointer.
5491  * If no dir entries were found, returns -ENOENT.
5492  * If found a corrupted location in dir entry, returns -EUCLEAN.
5493  */
5494 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
5495                                struct btrfs_key *location)
5496 {
5497         const char *name = dentry->d_name.name;
5498         int namelen = dentry->d_name.len;
5499         struct btrfs_dir_item *di;
5500         struct btrfs_path *path;
5501         struct btrfs_root *root = BTRFS_I(dir)->root;
5502         int ret = 0;
5503
5504         path = btrfs_alloc_path();
5505         if (!path)
5506                 return -ENOMEM;
5507
5508         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(BTRFS_I(dir)),
5509                         name, namelen, 0);
5510         if (!di) {
5511                 ret = -ENOENT;
5512                 goto out;
5513         }
5514         if (IS_ERR(di)) {
5515                 ret = PTR_ERR(di);
5516                 goto out;
5517         }
5518
5519         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
5520         if (location->type != BTRFS_INODE_ITEM_KEY &&
5521             location->type != BTRFS_ROOT_ITEM_KEY) {
5522                 ret = -EUCLEAN;
5523                 btrfs_warn(root->fs_info,
5524 "%s gets something invalid in DIR_ITEM (name %s, directory ino %llu, location(%llu %u %llu))",
5525                            __func__, name, btrfs_ino(BTRFS_I(dir)),
5526                            location->objectid, location->type, location->offset);
5527         }
5528 out:
5529         btrfs_free_path(path);
5530         return ret;
5531 }
5532
5533 /*
5534  * when we hit a tree root in a directory, the btrfs part of the inode
5535  * needs to be changed to reflect the root directory of the tree root.  This
5536  * is kind of like crossing a mount point.
5537  */
5538 static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
5539                                     struct inode *dir,
5540                                     struct dentry *dentry,
5541                                     struct btrfs_key *location,
5542                                     struct btrfs_root **sub_root)
5543 {
5544         struct btrfs_path *path;
5545         struct btrfs_root *new_root;
5546         struct btrfs_root_ref *ref;
5547         struct extent_buffer *leaf;
5548         struct btrfs_key key;
5549         int ret;
5550         int err = 0;
5551
5552         path = btrfs_alloc_path();
5553         if (!path) {
5554                 err = -ENOMEM;
5555                 goto out;
5556         }
5557
5558         err = -ENOENT;
5559         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5560         key.type = BTRFS_ROOT_REF_KEY;
5561         key.offset = location->objectid;
5562
5563         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
5564         if (ret) {
5565                 if (ret < 0)
5566                         err = ret;
5567                 goto out;
5568         }
5569
5570         leaf = path->nodes[0];
5571         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5572         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(BTRFS_I(dir)) ||
5573             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5574                 goto out;
5575
5576         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5577                                    (unsigned long)(ref + 1),
5578                                    dentry->d_name.len);
5579         if (ret)
5580                 goto out;
5581
5582         btrfs_release_path(path);
5583
5584         new_root = btrfs_read_fs_root_no_name(fs_info, location);
5585         if (IS_ERR(new_root)) {
5586                 err = PTR_ERR(new_root);
5587                 goto out;
5588         }
5589
5590         *sub_root = new_root;
5591         location->objectid = btrfs_root_dirid(&new_root->root_item);
5592         location->type = BTRFS_INODE_ITEM_KEY;
5593         location->offset = 0;
5594         err = 0;
5595 out:
5596         btrfs_free_path(path);
5597         return err;
5598 }
5599
5600 static void inode_tree_add(struct inode *inode)
5601 {
5602         struct btrfs_root *root = BTRFS_I(inode)->root;
5603         struct btrfs_inode *entry;
5604         struct rb_node **p;
5605         struct rb_node *parent;
5606         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5607         u64 ino = btrfs_ino(BTRFS_I(inode));
5608
5609         if (inode_unhashed(inode))
5610                 return;
5611         parent = NULL;
5612         spin_lock(&root->inode_lock);
5613         p = &root->inode_tree.rb_node;
5614         while (*p) {
5615                 parent = *p;
5616                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5617
5618                 if (ino < btrfs_ino(BTRFS_I(&entry->vfs_inode)))
5619                         p = &parent->rb_left;
5620                 else if (ino > btrfs_ino(BTRFS_I(&entry->vfs_inode)))
5621                         p = &parent->rb_right;
5622                 else {
5623                         WARN_ON(!(entry->vfs_inode.i_state &
5624                                   (I_WILL_FREE | I_FREEING)));
5625                         rb_replace_node(parent, new, &root->inode_tree);
5626                         RB_CLEAR_NODE(parent);
5627                         spin_unlock(&root->inode_lock);
5628                         return;
5629                 }
5630         }
5631         rb_link_node(new, parent, p);
5632         rb_insert_color(new, &root->inode_tree);
5633         spin_unlock(&root->inode_lock);
5634 }
5635
5636 static void inode_tree_del(struct inode *inode)
5637 {
5638         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5639         struct btrfs_root *root = BTRFS_I(inode)->root;
5640         int empty = 0;
5641
5642         spin_lock(&root->inode_lock);
5643         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5644                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5645                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5646                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5647         }
5648         spin_unlock(&root->inode_lock);
5649
5650         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5651                 synchronize_srcu(&fs_info->subvol_srcu);
5652                 spin_lock(&root->inode_lock);
5653                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5654                 spin_unlock(&root->inode_lock);
5655                 if (empty)
5656                         btrfs_add_dead_root(root);
5657         }
5658 }
5659
5660
5661 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5662 {
5663         struct btrfs_iget_args *args = p;
5664         inode->i_ino = args->location->objectid;
5665         memcpy(&BTRFS_I(inode)->location, args->location,
5666                sizeof(*args->location));
5667         BTRFS_I(inode)->root = args->root;
5668         return 0;
5669 }
5670
5671 static int btrfs_find_actor(struct inode *inode, void *opaque)
5672 {
5673         struct btrfs_iget_args *args = opaque;
5674         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5675                 args->root == BTRFS_I(inode)->root;
5676 }
5677
5678 static struct inode *btrfs_iget_locked(struct super_block *s,
5679                                        struct btrfs_key *location,
5680                                        struct btrfs_root *root)
5681 {
5682         struct inode *inode;
5683         struct btrfs_iget_args args;
5684         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5685
5686         args.location = location;
5687         args.root = root;
5688
5689         inode = iget5_locked(s, hashval, btrfs_find_actor,
5690                              btrfs_init_locked_inode,
5691                              (void *)&args);
5692         return inode;
5693 }
5694
5695 /* Get an inode object given its location and corresponding root.
5696  * Returns in *is_new if the inode was read from disk
5697  */
5698 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5699                          struct btrfs_root *root, int *new)
5700 {
5701         struct inode *inode;
5702
5703         inode = btrfs_iget_locked(s, location, root);
5704         if (!inode)
5705                 return ERR_PTR(-ENOMEM);
5706
5707         if (inode->i_state & I_NEW) {
5708                 int ret;
5709
5710                 ret = btrfs_read_locked_inode(inode);
5711                 if (!is_bad_inode(inode)) {
5712                         inode_tree_add(inode);
5713                         unlock_new_inode(inode);
5714                         if (new)
5715                                 *new = 1;
5716                 } else {
5717                         unlock_new_inode(inode);
5718                         iput(inode);
5719                         ASSERT(ret < 0);
5720                         inode = ERR_PTR(ret < 0 ? ret : -ESTALE);
5721                 }
5722         }
5723
5724         return inode;
5725 }
5726
5727 static struct inode *new_simple_dir(struct super_block *s,
5728                                     struct btrfs_key *key,
5729                                     struct btrfs_root *root)
5730 {
5731         struct inode *inode = new_inode(s);
5732
5733         if (!inode)
5734                 return ERR_PTR(-ENOMEM);
5735
5736         BTRFS_I(inode)->root = root;
5737         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5738         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5739
5740         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5741         inode->i_op = &btrfs_dir_ro_inode_operations;
5742         inode->i_opflags &= ~IOP_XATTR;
5743         inode->i_fop = &simple_dir_operations;
5744         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5745         inode->i_mtime = current_time(inode);
5746         inode->i_atime = inode->i_mtime;
5747         inode->i_ctime = inode->i_mtime;
5748         BTRFS_I(inode)->i_otime = timespec64_to_timespec(inode->i_mtime);
5749
5750         return inode;
5751 }
5752
5753 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5754 {
5755         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
5756         struct inode *inode;
5757         struct btrfs_root *root = BTRFS_I(dir)->root;
5758         struct btrfs_root *sub_root = root;
5759         struct btrfs_key location;
5760         int index;
5761         int ret = 0;
5762
5763         if (dentry->d_name.len > BTRFS_NAME_LEN)
5764                 return ERR_PTR(-ENAMETOOLONG);
5765
5766         ret = btrfs_inode_by_name(dir, dentry, &location);
5767         if (ret < 0)
5768                 return ERR_PTR(ret);
5769
5770         if (location.type == BTRFS_INODE_ITEM_KEY) {
5771                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5772                 return inode;
5773         }
5774
5775         index = srcu_read_lock(&fs_info->subvol_srcu);
5776         ret = fixup_tree_root_location(fs_info, dir, dentry,
5777                                        &location, &sub_root);
5778         if (ret < 0) {
5779                 if (ret != -ENOENT)
5780                         inode = ERR_PTR(ret);
5781                 else
5782                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5783         } else {
5784                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5785         }
5786         srcu_read_unlock(&fs_info->subvol_srcu, index);
5787
5788         if (!IS_ERR(inode) && root != sub_root) {
5789                 down_read(&fs_info->cleanup_work_sem);
5790                 if (!sb_rdonly(inode->i_sb))
5791                         ret = btrfs_orphan_cleanup(sub_root);
5792                 up_read(&fs_info->cleanup_work_sem);
5793                 if (ret) {
5794                         iput(inode);
5795                         inode = ERR_PTR(ret);
5796                 }
5797         }
5798
5799         return inode;
5800 }
5801
5802 static int btrfs_dentry_delete(const struct dentry *dentry)
5803 {
5804         struct btrfs_root *root;
5805         struct inode *inode = d_inode(dentry);
5806
5807         if (!inode && !IS_ROOT(dentry))
5808                 inode = d_inode(dentry->d_parent);
5809
5810         if (inode) {
5811                 root = BTRFS_I(inode)->root;
5812                 if (btrfs_root_refs(&root->root_item) == 0)
5813                         return 1;
5814
5815                 if (btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5816                         return 1;
5817         }
5818         return 0;
5819 }
5820
5821 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5822                                    unsigned int flags)
5823 {
5824         struct inode *inode;
5825
5826         inode = btrfs_lookup_dentry(dir, dentry);
5827         if (IS_ERR(inode)) {
5828                 if (PTR_ERR(inode) == -ENOENT)
5829                         inode = NULL;
5830                 else
5831                         return ERR_CAST(inode);
5832         }
5833
5834         return d_splice_alias(inode, dentry);
5835 }
5836
5837 unsigned char btrfs_filetype_table[] = {
5838         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5839 };
5840
5841 /*
5842  * All this infrastructure exists because dir_emit can fault, and we are holding
5843  * the tree lock when doing readdir.  For now just allocate a buffer and copy
5844  * our information into that, and then dir_emit from the buffer.  This is
5845  * similar to what NFS does, only we don't keep the buffer around in pagecache
5846  * because I'm afraid I'll mess that up.  Long term we need to make filldir do
5847  * copy_to_user_inatomic so we don't have to worry about page faulting under the
5848  * tree lock.
5849  */
5850 static int btrfs_opendir(struct inode *inode, struct file *file)
5851 {
5852         struct btrfs_file_private *private;
5853
5854         private = kzalloc(sizeof(struct btrfs_file_private), GFP_KERNEL);
5855         if (!private)
5856                 return -ENOMEM;
5857         private->filldir_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
5858         if (!private->filldir_buf) {
5859                 kfree(private);
5860                 return -ENOMEM;
5861         }
5862         file->private_data = private;
5863         return 0;
5864 }
5865
5866 struct dir_entry {
5867         u64 ino;
5868         u64 offset;
5869         unsigned type;
5870         int name_len;
5871 };
5872
5873 static int btrfs_filldir(void *addr, int entries, struct dir_context *ctx)
5874 {
5875         while (entries--) {
5876                 struct dir_entry *entry = addr;
5877                 char *name = (char *)(entry + 1);
5878
5879                 ctx->pos = get_unaligned(&entry->offset);
5880                 if (!dir_emit(ctx, name, get_unaligned(&entry->name_len),
5881                                          get_unaligned(&entry->ino),
5882                                          get_unaligned(&entry->type)))
5883                         return 1;
5884                 addr += sizeof(struct dir_entry) +
5885                         get_unaligned(&entry->name_len);
5886                 ctx->pos++;
5887         }
5888         return 0;
5889 }
5890
5891 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5892 {
5893         struct inode *inode = file_inode(file);
5894         struct btrfs_root *root = BTRFS_I(inode)->root;
5895         struct btrfs_file_private *private = file->private_data;
5896         struct btrfs_dir_item *di;
5897         struct btrfs_key key;
5898         struct btrfs_key found_key;
5899         struct btrfs_path *path;
5900         void *addr;
5901         struct list_head ins_list;
5902         struct list_head del_list;
5903         int ret;
5904         struct extent_buffer *leaf;
5905         int slot;
5906         char *name_ptr;
5907         int name_len;
5908         int entries = 0;
5909         int total_len = 0;
5910         bool put = false;
5911         struct btrfs_key location;
5912
5913         if (!dir_emit_dots(file, ctx))
5914                 return 0;
5915
5916         path = btrfs_alloc_path();
5917         if (!path)
5918                 return -ENOMEM;
5919
5920         addr = private->filldir_buf;
5921         path->reada = READA_FORWARD;
5922
5923         INIT_LIST_HEAD(&ins_list);
5924         INIT_LIST_HEAD(&del_list);
5925         put = btrfs_readdir_get_delayed_items(inode, &ins_list, &del_list);
5926
5927 again:
5928         key.type = BTRFS_DIR_INDEX_KEY;
5929         key.offset = ctx->pos;
5930         key.objectid = btrfs_ino(BTRFS_I(inode));
5931
5932         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5933         if (ret < 0)
5934                 goto err;
5935
5936         while (1) {
5937                 struct dir_entry *entry;
5938
5939                 leaf = path->nodes[0];
5940                 slot = path->slots[0];
5941                 if (slot >= btrfs_header_nritems(leaf)) {
5942                         ret = btrfs_next_leaf(root, path);
5943                         if (ret < 0)
5944                                 goto err;
5945                         else if (ret > 0)
5946                                 break;
5947                         continue;
5948                 }
5949
5950                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5951
5952                 if (found_key.objectid != key.objectid)
5953                         break;
5954                 if (found_key.type != BTRFS_DIR_INDEX_KEY)
5955                         break;
5956                 if (found_key.offset < ctx->pos)
5957                         goto next;
5958                 if (btrfs_should_delete_dir_index(&del_list, found_key.offset))
5959                         goto next;
5960                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5961                 name_len = btrfs_dir_name_len(leaf, di);
5962                 if ((total_len + sizeof(struct dir_entry) + name_len) >=
5963                     PAGE_SIZE) {
5964                         btrfs_release_path(path);
5965                         ret = btrfs_filldir(private->filldir_buf, entries, ctx);
5966                         if (ret)
5967                                 goto nopos;
5968                         addr = private->filldir_buf;
5969                         entries = 0;
5970                         total_len = 0;
5971                         goto again;
5972                 }
5973
5974                 entry = addr;
5975                 put_unaligned(name_len, &entry->name_len);
5976                 name_ptr = (char *)(entry + 1);
5977                 read_extent_buffer(leaf, name_ptr, (unsigned long)(di + 1),
5978                                    name_len);
5979                 put_unaligned(btrfs_filetype_table[btrfs_dir_type(leaf, di)],
5980                                 &entry->type);
5981                 btrfs_dir_item_key_to_cpu(leaf, di, &location);
5982                 put_unaligned(location.objectid, &entry->ino);
5983                 put_unaligned(found_key.offset, &entry->offset);
5984                 entries++;
5985                 addr += sizeof(struct dir_entry) + name_len;
5986                 total_len += sizeof(struct dir_entry) + name_len;
5987 next:
5988                 path->slots[0]++;
5989         }
5990         btrfs_release_path(path);
5991
5992         ret = btrfs_filldir(private->filldir_buf, entries, ctx);
5993         if (ret)
5994                 goto nopos;
5995
5996         ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5997         if (ret)
5998                 goto nopos;
5999
6000         /*
6001          * Stop new entries from being returned after we return the last
6002          * entry.
6003          *
6004          * New directory entries are assigned a strictly increasing
6005          * offset.  This means that new entries created during readdir
6006          * are *guaranteed* to be seen in the future by that readdir.
6007          * This has broken buggy programs which operate on names as
6008          * they're returned by readdir.  Until we re-use freed offsets
6009          * we have this hack to stop new entries from being returned
6010          * under the assumption that they'll never reach this huge
6011          * offset.
6012          *
6013          * This is being careful not to overflow 32bit loff_t unless the
6014          * last entry requires it because doing so has broken 32bit apps
6015          * in the past.
6016          */
6017         if (ctx->pos >= INT_MAX)
6018                 ctx->pos = LLONG_MAX;
6019         else
6020                 ctx->pos = INT_MAX;
6021 nopos:
6022         ret = 0;
6023 err:
6024         if (put)
6025                 btrfs_readdir_put_delayed_items(inode, &ins_list, &del_list);
6026         btrfs_free_path(path);
6027         return ret;
6028 }
6029
6030 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
6031 {
6032         struct btrfs_root *root = BTRFS_I(inode)->root;
6033         struct btrfs_trans_handle *trans;
6034         int ret = 0;
6035         bool nolock = false;
6036
6037         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
6038                 return 0;
6039
6040         if (btrfs_fs_closing(root->fs_info) &&
6041                         btrfs_is_free_space_inode(BTRFS_I(inode)))
6042                 nolock = true;
6043
6044         if (wbc->sync_mode == WB_SYNC_ALL) {
6045                 if (nolock)
6046                         trans = btrfs_join_transaction_nolock(root);
6047                 else
6048                         trans = btrfs_join_transaction(root);
6049                 if (IS_ERR(trans))
6050                         return PTR_ERR(trans);
6051                 ret = btrfs_commit_transaction(trans);
6052         }
6053         return ret;
6054 }
6055
6056 /*
6057  * This is somewhat expensive, updating the tree every time the
6058  * inode changes.  But, it is most likely to find the inode in cache.
6059  * FIXME, needs more benchmarking...there are no reasons other than performance
6060  * to keep or drop this code.
6061  */
6062 static int btrfs_dirty_inode(struct inode *inode)
6063 {
6064         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6065         struct btrfs_root *root = BTRFS_I(inode)->root;
6066         struct btrfs_trans_handle *trans;
6067         int ret;
6068
6069         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
6070                 return 0;
6071
6072         trans = btrfs_join_transaction(root);
6073         if (IS_ERR(trans))
6074                 return PTR_ERR(trans);
6075
6076         ret = btrfs_update_inode(trans, root, inode);
6077         if (ret && ret == -ENOSPC) {
6078                 /* whoops, lets try again with the full transaction */
6079                 btrfs_end_transaction(trans);
6080                 trans = btrfs_start_transaction(root, 1);
6081                 if (IS_ERR(trans))
6082                         return PTR_ERR(trans);
6083
6084                 ret = btrfs_update_inode(trans, root, inode);
6085         }
6086         btrfs_end_transaction(trans);
6087         if (BTRFS_I(inode)->delayed_node)
6088                 btrfs_balance_delayed_items(fs_info);
6089
6090         return ret;
6091 }
6092
6093 /*
6094  * This is a copy of file_update_time.  We need this so we can return error on
6095  * ENOSPC for updating the inode in the case of file write and mmap writes.
6096  */
6097 static int btrfs_update_time(struct inode *inode, struct timespec64 *now,
6098                              int flags)
6099 {
6100         struct btrfs_root *root = BTRFS_I(inode)->root;
6101         bool dirty = flags & ~S_VERSION;
6102
6103         if (btrfs_root_readonly(root))
6104                 return -EROFS;
6105
6106         if (flags & S_VERSION)
6107                 dirty |= inode_maybe_inc_iversion(inode, dirty);
6108         if (flags & S_CTIME)
6109                 inode->i_ctime = *now;
6110         if (flags & S_MTIME)
6111                 inode->i_mtime = *now;
6112         if (flags & S_ATIME)
6113                 inode->i_atime = *now;
6114         return dirty ? btrfs_dirty_inode(inode) : 0;
6115 }
6116
6117 /*
6118  * find the highest existing sequence number in a directory
6119  * and then set the in-memory index_cnt variable to reflect
6120  * free sequence numbers
6121  */
6122 static int btrfs_set_inode_index_count(struct btrfs_inode *inode)
6123 {
6124         struct btrfs_root *root = inode->root;
6125         struct btrfs_key key, found_key;
6126         struct btrfs_path *path;
6127         struct extent_buffer *leaf;
6128         int ret;
6129
6130         key.objectid = btrfs_ino(inode);
6131         key.type = BTRFS_DIR_INDEX_KEY;
6132         key.offset = (u64)-1;
6133
6134         path = btrfs_alloc_path();
6135         if (!path)
6136                 return -ENOMEM;
6137
6138         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6139         if (ret < 0)
6140                 goto out;
6141         /* FIXME: we should be able to handle this */
6142         if (ret == 0)
6143                 goto out;
6144         ret = 0;
6145
6146         /*
6147          * MAGIC NUMBER EXPLANATION:
6148          * since we search a directory based on f_pos we have to start at 2
6149          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
6150          * else has to start at 2
6151          */
6152         if (path->slots[0] == 0) {
6153                 inode->index_cnt = 2;
6154                 goto out;
6155         }
6156
6157         path->slots[0]--;
6158
6159         leaf = path->nodes[0];
6160         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6161
6162         if (found_key.objectid != btrfs_ino(inode) ||
6163             found_key.type != BTRFS_DIR_INDEX_KEY) {
6164                 inode->index_cnt = 2;
6165                 goto out;
6166         }
6167
6168         inode->index_cnt = found_key.offset + 1;
6169 out:
6170         btrfs_free_path(path);
6171         return ret;
6172 }
6173
6174 /*
6175  * helper to find a free sequence number in a given directory.  This current
6176  * code is very simple, later versions will do smarter things in the btree
6177  */
6178 int btrfs_set_inode_index(struct btrfs_inode *dir, u64 *index)
6179 {
6180         int ret = 0;
6181
6182         if (dir->index_cnt == (u64)-1) {
6183                 ret = btrfs_inode_delayed_dir_index_count(dir);
6184                 if (ret) {
6185                         ret = btrfs_set_inode_index_count(dir);
6186                         if (ret)
6187                                 return ret;
6188                 }
6189         }
6190
6191         *index = dir->index_cnt;
6192         dir->index_cnt++;
6193
6194         return ret;
6195 }
6196
6197 static int btrfs_insert_inode_locked(struct inode *inode)
6198 {
6199         struct btrfs_iget_args args;
6200         args.location = &BTRFS_I(inode)->location;
6201         args.root = BTRFS_I(inode)->root;
6202
6203         return insert_inode_locked4(inode,
6204                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
6205                    btrfs_find_actor, &args);
6206 }
6207
6208 /*
6209  * Inherit flags from the parent inode.
6210  *
6211  * Currently only the compression flags and the cow flags are inherited.
6212  */
6213 static void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
6214 {
6215         unsigned int flags;
6216
6217         if (!dir)
6218                 return;
6219
6220         flags = BTRFS_I(dir)->flags;
6221
6222         if (flags & BTRFS_INODE_NOCOMPRESS) {
6223                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
6224                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
6225         } else if (flags & BTRFS_INODE_COMPRESS) {
6226                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
6227                 BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
6228         }
6229
6230         if (flags & BTRFS_INODE_NODATACOW) {
6231                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
6232                 if (S_ISREG(inode->i_mode))
6233                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6234         }
6235
6236         btrfs_sync_inode_flags_to_i_flags(inode);
6237 }
6238
6239 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
6240                                      struct btrfs_root *root,
6241                                      struct inode *dir,
6242                                      const char *name, int name_len,
6243                                      u64 ref_objectid, u64 objectid,
6244                                      umode_t mode, u64 *index)
6245 {
6246         struct btrfs_fs_info *fs_info = root->fs_info;
6247         struct inode *inode;
6248         struct btrfs_inode_item *inode_item;
6249         struct btrfs_key *location;
6250         struct btrfs_path *path;
6251         struct btrfs_inode_ref *ref;
6252         struct btrfs_key key[2];
6253         u32 sizes[2];
6254         int nitems = name ? 2 : 1;
6255         unsigned long ptr;
6256         int ret;
6257
6258         path = btrfs_alloc_path();
6259         if (!path)
6260                 return ERR_PTR(-ENOMEM);
6261
6262         inode = new_inode(fs_info->sb);
6263         if (!inode) {
6264                 btrfs_free_path(path);
6265                 return ERR_PTR(-ENOMEM);
6266         }
6267
6268         /*
6269          * O_TMPFILE, set link count to 0, so that after this point,
6270          * we fill in an inode item with the correct link count.
6271          */
6272         if (!name)
6273                 set_nlink(inode, 0);
6274
6275         /*
6276          * we have to initialize this early, so we can reclaim the inode
6277          * number if we fail afterwards in this function.
6278          */
6279         inode->i_ino = objectid;
6280
6281         if (dir && name) {
6282                 trace_btrfs_inode_request(dir);
6283
6284                 ret = btrfs_set_inode_index(BTRFS_I(dir), index);
6285                 if (ret) {
6286                         btrfs_free_path(path);
6287                         iput(inode);
6288                         return ERR_PTR(ret);
6289                 }
6290         } else if (dir) {
6291                 *index = 0;
6292         }
6293         /*
6294          * index_cnt is ignored for everything but a dir,
6295          * btrfs_set_inode_index_count has an explanation for the magic
6296          * number
6297          */
6298         BTRFS_I(inode)->index_cnt = 2;
6299         BTRFS_I(inode)->dir_index = *index;
6300         BTRFS_I(inode)->root = root;
6301         BTRFS_I(inode)->generation = trans->transid;
6302         inode->i_generation = BTRFS_I(inode)->generation;
6303
6304         /*
6305          * We could have gotten an inode number from somebody who was fsynced
6306          * and then removed in this same transaction, so let's just set full
6307          * sync since it will be a full sync anyway and this will blow away the
6308          * old info in the log.
6309          */
6310         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
6311
6312         key[0].objectid = objectid;
6313         key[0].type = BTRFS_INODE_ITEM_KEY;
6314         key[0].offset = 0;
6315
6316         sizes[0] = sizeof(struct btrfs_inode_item);
6317
6318         if (name) {
6319                 /*
6320                  * Start new inodes with an inode_ref. This is slightly more
6321                  * efficient for small numbers of hard links since they will
6322                  * be packed into one item. Extended refs will kick in if we
6323                  * add more hard links than can fit in the ref item.
6324                  */
6325                 key[1].objectid = objectid;
6326                 key[1].type = BTRFS_INODE_REF_KEY;
6327                 key[1].offset = ref_objectid;
6328
6329                 sizes[1] = name_len + sizeof(*ref);
6330         }
6331
6332         location = &BTRFS_I(inode)->location;
6333         location->objectid = objectid;
6334         location->offset = 0;
6335         location->type = BTRFS_INODE_ITEM_KEY;
6336
6337         ret = btrfs_insert_inode_locked(inode);
6338         if (ret < 0)
6339                 goto fail;
6340
6341         path->leave_spinning = 1;
6342         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
6343         if (ret != 0)
6344                 goto fail_unlock;
6345
6346         inode_init_owner(inode, dir, mode);
6347         inode_set_bytes(inode, 0);
6348
6349         inode->i_mtime = current_time(inode);
6350         inode->i_atime = inode->i_mtime;
6351         inode->i_ctime = inode->i_mtime;
6352         BTRFS_I(inode)->i_otime = timespec64_to_timespec(inode->i_mtime);
6353
6354         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
6355                                   struct btrfs_inode_item);
6356         memzero_extent_buffer(path->nodes[0], (unsigned long)inode_item,
6357                              sizeof(*inode_item));
6358         fill_inode_item(trans, path->nodes[0], inode_item, inode);
6359
6360         if (name) {
6361                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
6362                                      struct btrfs_inode_ref);
6363                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
6364                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
6365                 ptr = (unsigned long)(ref + 1);
6366                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
6367         }
6368
6369         btrfs_mark_buffer_dirty(path->nodes[0]);
6370         btrfs_free_path(path);
6371
6372         btrfs_inherit_iflags(inode, dir);
6373
6374         if (S_ISREG(mode)) {
6375                 if (btrfs_test_opt(fs_info, NODATASUM))
6376                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6377                 if (btrfs_test_opt(fs_info, NODATACOW))
6378                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
6379                                 BTRFS_INODE_NODATASUM;
6380         }
6381
6382         inode_tree_add(inode);
6383
6384         trace_btrfs_inode_new(inode);
6385         btrfs_set_inode_last_trans(trans, inode);
6386
6387         btrfs_update_root_times(trans, root);
6388
6389         ret = btrfs_inode_inherit_props(trans, inode, dir);
6390         if (ret)
6391                 btrfs_err(fs_info,
6392                           "error inheriting props for ino %llu (root %llu): %d",
6393                         btrfs_ino(BTRFS_I(inode)), root->root_key.objectid, ret);
6394
6395         return inode;
6396
6397 fail_unlock:
6398         unlock_new_inode(inode);
6399 fail:
6400         if (dir && name)
6401                 BTRFS_I(dir)->index_cnt--;
6402         btrfs_free_path(path);
6403         iput(inode);
6404         return ERR_PTR(ret);
6405 }
6406
6407 static inline u8 btrfs_inode_type(struct inode *inode)
6408 {
6409         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
6410 }
6411
6412 /*
6413  * utility function to add 'inode' into 'parent_inode' with
6414  * a give name and a given sequence number.
6415  * if 'add_backref' is true, also insert a backref from the
6416  * inode to the parent directory.
6417  */
6418 int btrfs_add_link(struct btrfs_trans_handle *trans,
6419                    struct btrfs_inode *parent_inode, struct btrfs_inode *inode,
6420                    const char *name, int name_len, int add_backref, u64 index)
6421 {
6422         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6423         int ret = 0;
6424         struct btrfs_key key;
6425         struct btrfs_root *root = parent_inode->root;
6426         u64 ino = btrfs_ino(inode);
6427         u64 parent_ino = btrfs_ino(parent_inode);
6428
6429         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6430                 memcpy(&key, &inode->root->root_key, sizeof(key));
6431         } else {
6432                 key.objectid = ino;
6433                 key.type = BTRFS_INODE_ITEM_KEY;
6434                 key.offset = 0;
6435         }
6436
6437         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6438                 ret = btrfs_add_root_ref(trans, fs_info, key.objectid,
6439                                          root->root_key.objectid, parent_ino,
6440                                          index, name, name_len);
6441         } else if (add_backref) {
6442                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
6443                                              parent_ino, index);
6444         }
6445
6446         /* Nothing to clean up yet */
6447         if (ret)
6448                 return ret;
6449
6450         ret = btrfs_insert_dir_item(trans, root, name, name_len,
6451                                     parent_inode, &key,
6452                                     btrfs_inode_type(&inode->vfs_inode), index);
6453         if (ret == -EEXIST || ret == -EOVERFLOW)
6454                 goto fail_dir_item;
6455         else if (ret) {
6456                 btrfs_abort_transaction(trans, ret);
6457                 return ret;
6458         }
6459
6460         btrfs_i_size_write(parent_inode, parent_inode->vfs_inode.i_size +
6461                            name_len * 2);
6462         inode_inc_iversion(&parent_inode->vfs_inode);
6463         parent_inode->vfs_inode.i_mtime = parent_inode->vfs_inode.i_ctime =
6464                 current_time(&parent_inode->vfs_inode);
6465         ret = btrfs_update_inode(trans, root, &parent_inode->vfs_inode);
6466         if (ret)
6467                 btrfs_abort_transaction(trans, ret);
6468         return ret;
6469
6470 fail_dir_item:
6471         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6472                 u64 local_index;
6473                 int err;
6474                 err = btrfs_del_root_ref(trans, fs_info, key.objectid,
6475                                          root->root_key.objectid, parent_ino,
6476                                          &local_index, name, name_len);
6477
6478         } else if (add_backref) {
6479                 u64 local_index;
6480                 int err;
6481
6482                 err = btrfs_del_inode_ref(trans, root, name, name_len,
6483                                           ino, parent_ino, &local_index);
6484         }
6485         return ret;
6486 }
6487
6488 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
6489                             struct btrfs_inode *dir, struct dentry *dentry,
6490                             struct btrfs_inode *inode, int backref, u64 index)
6491 {
6492         int err = btrfs_add_link(trans, dir, inode,
6493                                  dentry->d_name.name, dentry->d_name.len,
6494                                  backref, index);
6495         if (err > 0)
6496                 err = -EEXIST;
6497         return err;
6498 }
6499
6500 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
6501                         umode_t mode, dev_t rdev)
6502 {
6503         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6504         struct btrfs_trans_handle *trans;
6505         struct btrfs_root *root = BTRFS_I(dir)->root;
6506         struct inode *inode = NULL;
6507         int err;
6508         int drop_inode = 0;
6509         u64 objectid;
6510         u64 index = 0;
6511
6512         /*
6513          * 2 for inode item and ref
6514          * 2 for dir items
6515          * 1 for xattr if selinux is on
6516          */
6517         trans = btrfs_start_transaction(root, 5);
6518         if (IS_ERR(trans))
6519                 return PTR_ERR(trans);
6520
6521         err = btrfs_find_free_ino(root, &objectid);
6522         if (err)
6523                 goto out_unlock;
6524
6525         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6526                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6527                         mode, &index);
6528         if (IS_ERR(inode)) {
6529                 err = PTR_ERR(inode);
6530                 goto out_unlock;
6531         }
6532
6533         /*
6534         * If the active LSM wants to access the inode during
6535         * d_instantiate it needs these. Smack checks to see
6536         * if the filesystem supports xattrs by looking at the
6537         * ops vector.
6538         */
6539         inode->i_op = &btrfs_special_inode_operations;
6540         init_special_inode(inode, inode->i_mode, rdev);
6541
6542         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6543         if (err)
6544                 goto out_unlock_inode;
6545
6546         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6547                         0, index);
6548         if (err) {
6549                 goto out_unlock_inode;
6550         } else {
6551                 btrfs_update_inode(trans, root, inode);
6552                 d_instantiate_new(dentry, inode);
6553         }
6554
6555 out_unlock:
6556         btrfs_end_transaction(trans);
6557         btrfs_btree_balance_dirty(fs_info);
6558         if (drop_inode) {
6559                 inode_dec_link_count(inode);
6560                 iput(inode);
6561         }
6562         return err;
6563
6564 out_unlock_inode:
6565         drop_inode = 1;
6566         unlock_new_inode(inode);
6567         goto out_unlock;
6568
6569 }
6570
6571 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6572                         umode_t mode, bool excl)
6573 {
6574         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6575         struct btrfs_trans_handle *trans;
6576         struct btrfs_root *root = BTRFS_I(dir)->root;
6577         struct inode *inode = NULL;
6578         int drop_inode_on_err = 0;
6579         int err;
6580         u64 objectid;
6581         u64 index = 0;
6582
6583         /*
6584          * 2 for inode item and ref
6585          * 2 for dir items
6586          * 1 for xattr if selinux is on
6587          */
6588         trans = btrfs_start_transaction(root, 5);
6589         if (IS_ERR(trans))
6590                 return PTR_ERR(trans);
6591
6592         err = btrfs_find_free_ino(root, &objectid);
6593         if (err)
6594                 goto out_unlock;
6595
6596         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6597                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6598                         mode, &index);
6599         if (IS_ERR(inode)) {
6600                 err = PTR_ERR(inode);
6601                 goto out_unlock;
6602         }
6603         drop_inode_on_err = 1;
6604         /*
6605         * If the active LSM wants to access the inode during
6606         * d_instantiate it needs these. Smack checks to see
6607         * if the filesystem supports xattrs by looking at the
6608         * ops vector.
6609         */
6610         inode->i_fop = &btrfs_file_operations;
6611         inode->i_op = &btrfs_file_inode_operations;
6612         inode->i_mapping->a_ops = &btrfs_aops;
6613
6614         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6615         if (err)
6616                 goto out_unlock_inode;
6617
6618         err = btrfs_update_inode(trans, root, inode);
6619         if (err)
6620                 goto out_unlock_inode;
6621
6622         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6623                         0, index);
6624         if (err)
6625                 goto out_unlock_inode;
6626
6627         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6628         d_instantiate_new(dentry, inode);
6629
6630 out_unlock:
6631         btrfs_end_transaction(trans);
6632         if (err && drop_inode_on_err) {
6633                 inode_dec_link_count(inode);
6634                 iput(inode);
6635         }
6636         btrfs_btree_balance_dirty(fs_info);
6637         return err;
6638
6639 out_unlock_inode:
6640         unlock_new_inode(inode);
6641         goto out_unlock;
6642
6643 }
6644
6645 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6646                       struct dentry *dentry)
6647 {
6648         struct btrfs_trans_handle *trans = NULL;
6649         struct btrfs_root *root = BTRFS_I(dir)->root;
6650         struct inode *inode = d_inode(old_dentry);
6651         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6652         u64 index;
6653         int err;
6654         int drop_inode = 0;
6655
6656         /* do not allow sys_link's with other subvols of the same device */
6657         if (root->objectid != BTRFS_I(inode)->root->objectid)
6658                 return -EXDEV;
6659
6660         if (inode->i_nlink >= BTRFS_LINK_MAX)
6661                 return -EMLINK;
6662
6663         err = btrfs_set_inode_index(BTRFS_I(dir), &index);
6664         if (err)
6665                 goto fail;
6666
6667         /*
6668          * 2 items for inode and inode ref
6669          * 2 items for dir items
6670          * 1 item for parent inode
6671          * 1 item for orphan item deletion if O_TMPFILE
6672          */
6673         trans = btrfs_start_transaction(root, inode->i_nlink ? 5 : 6);
6674         if (IS_ERR(trans)) {
6675                 err = PTR_ERR(trans);
6676                 trans = NULL;
6677                 goto fail;
6678         }
6679
6680         /* There are several dir indexes for this inode, clear the cache. */
6681         BTRFS_I(inode)->dir_index = 0ULL;
6682         inc_nlink(inode);
6683         inode_inc_iversion(inode);
6684         inode->i_ctime = current_time(inode);
6685         ihold(inode);
6686         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6687
6688         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6689                         1, index);
6690
6691         if (err) {
6692                 drop_inode = 1;
6693         } else {
6694                 struct dentry *parent = dentry->d_parent;
6695                 err = btrfs_update_inode(trans, root, inode);
6696                 if (err)
6697                         goto fail;
6698                 if (inode->i_nlink == 1) {
6699                         /*
6700                          * If new hard link count is 1, it's a file created
6701                          * with open(2) O_TMPFILE flag.
6702                          */
6703                         err = btrfs_orphan_del(trans, BTRFS_I(inode));
6704                         if (err)
6705                                 goto fail;
6706                 }
6707                 d_instantiate(dentry, inode);
6708                 btrfs_log_new_name(trans, BTRFS_I(inode), NULL, parent);
6709         }
6710
6711 fail:
6712         if (trans)
6713                 btrfs_end_transaction(trans);
6714         if (drop_inode) {
6715                 inode_dec_link_count(inode);
6716                 iput(inode);
6717         }
6718         btrfs_btree_balance_dirty(fs_info);
6719         return err;
6720 }
6721
6722 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6723 {
6724         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6725         struct inode *inode = NULL;
6726         struct btrfs_trans_handle *trans;
6727         struct btrfs_root *root = BTRFS_I(dir)->root;
6728         int err = 0;
6729         int drop_on_err = 0;
6730         u64 objectid = 0;
6731         u64 index = 0;
6732
6733         /*
6734          * 2 items for inode and ref
6735          * 2 items for dir items
6736          * 1 for xattr if selinux is on
6737          */
6738         trans = btrfs_start_transaction(root, 5);
6739         if (IS_ERR(trans))
6740                 return PTR_ERR(trans);
6741
6742         err = btrfs_find_free_ino(root, &objectid);
6743         if (err)
6744                 goto out_fail;
6745
6746         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6747                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6748                         S_IFDIR | mode, &index);
6749         if (IS_ERR(inode)) {
6750                 err = PTR_ERR(inode);
6751                 goto out_fail;
6752         }
6753
6754         drop_on_err = 1;
6755         /* these must be set before we unlock the inode */
6756         inode->i_op = &btrfs_dir_inode_operations;
6757         inode->i_fop = &btrfs_dir_file_operations;
6758
6759         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6760         if (err)
6761                 goto out_fail_inode;
6762
6763         btrfs_i_size_write(BTRFS_I(inode), 0);
6764         err = btrfs_update_inode(trans, root, inode);
6765         if (err)
6766                 goto out_fail_inode;
6767
6768         err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
6769                         dentry->d_name.name,
6770                         dentry->d_name.len, 0, index);
6771         if (err)
6772                 goto out_fail_inode;
6773
6774         d_instantiate_new(dentry, inode);
6775         drop_on_err = 0;
6776
6777 out_fail:
6778         btrfs_end_transaction(trans);
6779         if (drop_on_err) {
6780                 inode_dec_link_count(inode);
6781                 iput(inode);
6782         }
6783         btrfs_btree_balance_dirty(fs_info);
6784         return err;
6785
6786 out_fail_inode:
6787         unlock_new_inode(inode);
6788         goto out_fail;
6789 }
6790
6791 static noinline int uncompress_inline(struct btrfs_path *path,
6792                                       struct page *page,
6793                                       size_t pg_offset, u64 extent_offset,
6794                                       struct btrfs_file_extent_item *item)
6795 {
6796         int ret;
6797         struct extent_buffer *leaf = path->nodes[0];
6798         char *tmp;
6799         size_t max_size;
6800         unsigned long inline_size;
6801         unsigned long ptr;
6802         int compress_type;
6803
6804         WARN_ON(pg_offset != 0);
6805         compress_type = btrfs_file_extent_compression(leaf, item);
6806         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6807         inline_size = btrfs_file_extent_inline_item_len(leaf,
6808                                         btrfs_item_nr(path->slots[0]));
6809         tmp = kmalloc(inline_size, GFP_NOFS);
6810         if (!tmp)
6811                 return -ENOMEM;
6812         ptr = btrfs_file_extent_inline_start(item);
6813
6814         read_extent_buffer(leaf, tmp, ptr, inline_size);
6815
6816         max_size = min_t(unsigned long, PAGE_SIZE, max_size);
6817         ret = btrfs_decompress(compress_type, tmp, page,
6818                                extent_offset, inline_size, max_size);
6819
6820         /*
6821          * decompression code contains a memset to fill in any space between the end
6822          * of the uncompressed data and the end of max_size in case the decompressed
6823          * data ends up shorter than ram_bytes.  That doesn't cover the hole between
6824          * the end of an inline extent and the beginning of the next block, so we
6825          * cover that region here.
6826          */
6827
6828         if (max_size + pg_offset < PAGE_SIZE) {
6829                 char *map = kmap(page);
6830                 memset(map + pg_offset + max_size, 0, PAGE_SIZE - max_size - pg_offset);
6831                 kunmap(page);
6832         }
6833         kfree(tmp);
6834         return ret;
6835 }
6836
6837 /*
6838  * a bit scary, this does extent mapping from logical file offset to the disk.
6839  * the ugly parts come from merging extents from the disk with the in-ram
6840  * representation.  This gets more complex because of the data=ordered code,
6841  * where the in-ram extents might be locked pending data=ordered completion.
6842  *
6843  * This also copies inline extents directly into the page.
6844  */
6845 struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
6846                 struct page *page,
6847             size_t pg_offset, u64 start, u64 len,
6848                 int create)
6849 {
6850         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6851         int ret;
6852         int err = 0;
6853         u64 extent_start = 0;
6854         u64 extent_end = 0;
6855         u64 objectid = btrfs_ino(inode);
6856         u32 found_type;
6857         struct btrfs_path *path = NULL;
6858         struct btrfs_root *root = inode->root;
6859         struct btrfs_file_extent_item *item;
6860         struct extent_buffer *leaf;
6861         struct btrfs_key found_key;
6862         struct extent_map *em = NULL;
6863         struct extent_map_tree *em_tree = &inode->extent_tree;
6864         struct extent_io_tree *io_tree = &inode->io_tree;
6865         const bool new_inline = !page || create;
6866
6867         read_lock(&em_tree->lock);
6868         em = lookup_extent_mapping(em_tree, start, len);
6869         if (em)
6870                 em->bdev = fs_info->fs_devices->latest_bdev;
6871         read_unlock(&em_tree->lock);
6872
6873         if (em) {
6874                 if (em->start > start || em->start + em->len <= start)
6875                         free_extent_map(em);
6876                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6877                         free_extent_map(em);
6878                 else
6879                         goto out;
6880         }
6881         em = alloc_extent_map();
6882         if (!em) {
6883                 err = -ENOMEM;
6884                 goto out;
6885         }
6886         em->bdev = fs_info->fs_devices->latest_bdev;
6887         em->start = EXTENT_MAP_HOLE;
6888         em->orig_start = EXTENT_MAP_HOLE;
6889         em->len = (u64)-1;
6890         em->block_len = (u64)-1;
6891
6892         if (!path) {
6893                 path = btrfs_alloc_path();
6894                 if (!path) {
6895                         err = -ENOMEM;
6896                         goto out;
6897                 }
6898                 /*
6899                  * Chances are we'll be called again, so go ahead and do
6900                  * readahead
6901                  */
6902                 path->reada = READA_FORWARD;
6903         }
6904
6905         ret = btrfs_lookup_file_extent(NULL, root, path, objectid, start, 0);
6906         if (ret < 0) {
6907                 err = ret;
6908                 goto out;
6909         }
6910
6911         if (ret != 0) {
6912                 if (path->slots[0] == 0)
6913                         goto not_found;
6914                 path->slots[0]--;
6915         }
6916
6917         leaf = path->nodes[0];
6918         item = btrfs_item_ptr(leaf, path->slots[0],
6919                               struct btrfs_file_extent_item);
6920         /* are we inside the extent that was found? */
6921         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6922         found_type = found_key.type;
6923         if (found_key.objectid != objectid ||
6924             found_type != BTRFS_EXTENT_DATA_KEY) {
6925                 /*
6926                  * If we backup past the first extent we want to move forward
6927                  * and see if there is an extent in front of us, otherwise we'll
6928                  * say there is a hole for our whole search range which can
6929                  * cause problems.
6930                  */
6931                 extent_end = start;
6932                 goto next;
6933         }
6934
6935         found_type = btrfs_file_extent_type(leaf, item);
6936         extent_start = found_key.offset;
6937         if (found_type == BTRFS_FILE_EXTENT_REG ||
6938             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6939                 extent_end = extent_start +
6940                        btrfs_file_extent_num_bytes(leaf, item);
6941
6942                 trace_btrfs_get_extent_show_fi_regular(inode, leaf, item,
6943                                                        extent_start);
6944         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6945                 size_t size;
6946                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6947                 extent_end = ALIGN(extent_start + size,
6948                                    fs_info->sectorsize);
6949
6950                 trace_btrfs_get_extent_show_fi_inline(inode, leaf, item,
6951                                                       path->slots[0],
6952                                                       extent_start);
6953         }
6954 next:
6955         if (start >= extent_end) {
6956                 path->slots[0]++;
6957                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6958                         ret = btrfs_next_leaf(root, path);
6959                         if (ret < 0) {
6960                                 err = ret;
6961                                 goto out;
6962                         }
6963                         if (ret > 0)
6964                                 goto not_found;
6965                         leaf = path->nodes[0];
6966                 }
6967                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6968                 if (found_key.objectid != objectid ||
6969                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6970                         goto not_found;
6971                 if (start + len <= found_key.offset)
6972                         goto not_found;
6973                 if (start > found_key.offset)
6974                         goto next;
6975                 em->start = start;
6976                 em->orig_start = start;
6977                 em->len = found_key.offset - start;
6978                 goto not_found_em;
6979         }
6980
6981         btrfs_extent_item_to_extent_map(inode, path, item,
6982                         new_inline, em);
6983
6984         if (found_type == BTRFS_FILE_EXTENT_REG ||
6985             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6986                 goto insert;
6987         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6988                 unsigned long ptr;
6989                 char *map;
6990                 size_t size;
6991                 size_t extent_offset;
6992                 size_t copy_size;
6993
6994                 if (new_inline)
6995                         goto out;
6996
6997                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6998                 extent_offset = page_offset(page) + pg_offset - extent_start;
6999                 copy_size = min_t(u64, PAGE_SIZE - pg_offset,
7000                                   size - extent_offset);
7001                 em->start = extent_start + extent_offset;
7002                 em->len = ALIGN(copy_size, fs_info->sectorsize);
7003                 em->orig_block_len = em->len;
7004                 em->orig_start = em->start;
7005                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
7006                 if (!PageUptodate(page)) {
7007                         if (btrfs_file_extent_compression(leaf, item) !=
7008                             BTRFS_COMPRESS_NONE) {
7009                                 ret = uncompress_inline(path, page, pg_offset,
7010                                                         extent_offset, item);
7011                                 if (ret) {
7012                                         err = ret;
7013                                         goto out;
7014                                 }
7015                         } else {
7016                                 map = kmap(page);
7017                                 read_extent_buffer(leaf, map + pg_offset, ptr,
7018                                                    copy_size);
7019                                 if (pg_offset + copy_size < PAGE_SIZE) {
7020                                         memset(map + pg_offset + copy_size, 0,
7021                                                PAGE_SIZE - pg_offset -
7022                                                copy_size);
7023                                 }
7024                                 kunmap(page);
7025                         }
7026                         flush_dcache_page(page);
7027                 }
7028                 set_extent_uptodate(io_tree, em->start,
7029                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
7030                 goto insert;
7031         }
7032 not_found:
7033         em->start = start;
7034         em->orig_start = start;
7035         em->len = len;
7036 not_found_em:
7037         em->block_start = EXTENT_MAP_HOLE;
7038 insert:
7039         btrfs_release_path(path);
7040         if (em->start > start || extent_map_end(em) <= start) {
7041                 btrfs_err(fs_info,
7042                           "bad extent! em: [%llu %llu] passed [%llu %llu]",
7043                           em->start, em->len, start, len);
7044                 err = -EIO;
7045                 goto out;
7046         }
7047
7048         err = 0;
7049         write_lock(&em_tree->lock);
7050         err = btrfs_add_extent_mapping(fs_info, em_tree, &em, start, len);
7051         write_unlock(&em_tree->lock);
7052 out:
7053
7054         trace_btrfs_get_extent(root, inode, em);
7055
7056         btrfs_free_path(path);
7057         if (err) {
7058                 free_extent_map(em);
7059                 return ERR_PTR(err);
7060         }
7061         BUG_ON(!em); /* Error is always set */
7062         return em;
7063 }
7064
7065 struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode,
7066                 struct page *page,
7067                 size_t pg_offset, u64 start, u64 len,
7068                 int create)
7069 {
7070         struct extent_map *em;
7071         struct extent_map *hole_em = NULL;
7072         u64 range_start = start;
7073         u64 end;
7074         u64 found;
7075         u64 found_end;
7076         int err = 0;
7077
7078         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
7079         if (IS_ERR(em))
7080                 return em;
7081         /*
7082          * If our em maps to:
7083          * - a hole or
7084          * - a pre-alloc extent,
7085          * there might actually be delalloc bytes behind it.
7086          */
7087         if (em->block_start != EXTENT_MAP_HOLE &&
7088             !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7089                 return em;
7090         else
7091                 hole_em = em;
7092
7093         /* check to see if we've wrapped (len == -1 or similar) */
7094         end = start + len;
7095         if (end < start)
7096                 end = (u64)-1;
7097         else
7098                 end -= 1;
7099
7100         em = NULL;
7101
7102         /* ok, we didn't find anything, lets look for delalloc */
7103         found = count_range_bits(&inode->io_tree, &range_start,
7104                                  end, len, EXTENT_DELALLOC, 1);
7105         found_end = range_start + found;
7106         if (found_end < range_start)
7107                 found_end = (u64)-1;
7108
7109         /*
7110          * we didn't find anything useful, return
7111          * the original results from get_extent()
7112          */
7113         if (range_start > end || found_end <= start) {
7114                 em = hole_em;
7115                 hole_em = NULL;
7116                 goto out;
7117         }
7118
7119         /* adjust the range_start to make sure it doesn't
7120          * go backwards from the start they passed in
7121          */
7122         range_start = max(start, range_start);
7123         found = found_end - range_start;
7124
7125         if (found > 0) {
7126                 u64 hole_start = start;
7127                 u64 hole_len = len;
7128
7129                 em = alloc_extent_map();
7130                 if (!em) {
7131                         err = -ENOMEM;
7132                         goto out;
7133                 }
7134                 /*
7135                  * when btrfs_get_extent can't find anything it
7136                  * returns one huge hole
7137                  *
7138                  * make sure what it found really fits our range, and
7139                  * adjust to make sure it is based on the start from
7140                  * the caller
7141                  */
7142                 if (hole_em) {
7143                         u64 calc_end = extent_map_end(hole_em);
7144
7145                         if (calc_end <= start || (hole_em->start > end)) {
7146                                 free_extent_map(hole_em);
7147                                 hole_em = NULL;
7148                         } else {
7149                                 hole_start = max(hole_em->start, start);
7150                                 hole_len = calc_end - hole_start;
7151                         }
7152                 }
7153                 em->bdev = NULL;
7154                 if (hole_em && range_start > hole_start) {
7155                         /* our hole starts before our delalloc, so we
7156                          * have to return just the parts of the hole
7157                          * that go until  the delalloc starts
7158                          */
7159                         em->len = min(hole_len,
7160                                       range_start - hole_start);
7161                         em->start = hole_start;
7162                         em->orig_start = hole_start;
7163                         /*
7164                          * don't adjust block start at all,
7165                          * it is fixed at EXTENT_MAP_HOLE
7166                          */
7167                         em->block_start = hole_em->block_start;
7168                         em->block_len = hole_len;
7169                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
7170                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
7171                 } else {
7172                         em->start = range_start;
7173                         em->len = found;
7174                         em->orig_start = range_start;
7175                         em->block_start = EXTENT_MAP_DELALLOC;
7176                         em->block_len = found;
7177                 }
7178         } else {
7179                 return hole_em;
7180         }
7181 out:
7182
7183         free_extent_map(hole_em);
7184         if (err) {
7185                 free_extent_map(em);
7186                 return ERR_PTR(err);
7187         }
7188         return em;
7189 }
7190
7191 static struct extent_map *btrfs_create_dio_extent(struct inode *inode,
7192                                                   const u64 start,
7193                                                   const u64 len,
7194                                                   const u64 orig_start,
7195                                                   const u64 block_start,
7196                                                   const u64 block_len,
7197                                                   const u64 orig_block_len,
7198                                                   const u64 ram_bytes,
7199                                                   const int type)
7200 {
7201         struct extent_map *em = NULL;
7202         int ret;
7203
7204         if (type != BTRFS_ORDERED_NOCOW) {
7205                 em = create_io_em(inode, start, len, orig_start,
7206                                   block_start, block_len, orig_block_len,
7207                                   ram_bytes,
7208                                   BTRFS_COMPRESS_NONE, /* compress_type */
7209                                   type);
7210                 if (IS_ERR(em))
7211                         goto out;
7212         }
7213         ret = btrfs_add_ordered_extent_dio(inode, start, block_start,
7214                                            len, block_len, type);
7215         if (ret) {
7216                 if (em) {
7217                         free_extent_map(em);
7218                         btrfs_drop_extent_cache(BTRFS_I(inode), start,
7219                                                 start + len - 1, 0);
7220                 }
7221                 em = ERR_PTR(ret);
7222         }
7223  out:
7224
7225         return em;
7226 }
7227
7228 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
7229                                                   u64 start, u64 len)
7230 {
7231         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7232         struct btrfs_root *root = BTRFS_I(inode)->root;
7233         struct extent_map *em;
7234         struct btrfs_key ins;
7235         u64 alloc_hint;
7236         int ret;
7237
7238         alloc_hint = get_extent_allocation_hint(inode, start, len);
7239         ret = btrfs_reserve_extent(root, len, len, fs_info->sectorsize,
7240                                    0, alloc_hint, &ins, 1, 1);
7241         if (ret)
7242                 return ERR_PTR(ret);
7243
7244         em = btrfs_create_dio_extent(inode, start, ins.offset, start,
7245                                      ins.objectid, ins.offset, ins.offset,
7246                                      ins.offset, BTRFS_ORDERED_REGULAR);
7247         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
7248         if (IS_ERR(em))
7249                 btrfs_free_reserved_extent(fs_info, ins.objectid,
7250                                            ins.offset, 1);
7251
7252         return em;
7253 }
7254
7255 /*
7256  * returns 1 when the nocow is safe, < 1 on error, 0 if the
7257  * block must be cow'd
7258  */
7259 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
7260                               u64 *orig_start, u64 *orig_block_len,
7261                               u64 *ram_bytes)
7262 {
7263         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7264         struct btrfs_path *path;
7265         int ret;
7266         struct extent_buffer *leaf;
7267         struct btrfs_root *root = BTRFS_I(inode)->root;
7268         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7269         struct btrfs_file_extent_item *fi;
7270         struct btrfs_key key;
7271         u64 disk_bytenr;
7272         u64 backref_offset;
7273         u64 extent_end;
7274         u64 num_bytes;
7275         int slot;
7276         int found_type;
7277         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
7278
7279         path = btrfs_alloc_path();
7280         if (!path)
7281                 return -ENOMEM;
7282
7283         ret = btrfs_lookup_file_extent(NULL, root, path,
7284                         btrfs_ino(BTRFS_I(inode)), offset, 0);
7285         if (ret < 0)
7286                 goto out;
7287
7288         slot = path->slots[0];
7289         if (ret == 1) {
7290                 if (slot == 0) {
7291                         /* can't find the item, must cow */
7292                         ret = 0;
7293                         goto out;
7294                 }
7295                 slot--;
7296         }
7297         ret = 0;
7298         leaf = path->nodes[0];
7299         btrfs_item_key_to_cpu(leaf, &key, slot);
7300         if (key.objectid != btrfs_ino(BTRFS_I(inode)) ||
7301             key.type != BTRFS_EXTENT_DATA_KEY) {
7302                 /* not our file or wrong item type, must cow */
7303                 goto out;
7304         }
7305
7306         if (key.offset > offset) {
7307                 /* Wrong offset, must cow */
7308                 goto out;
7309         }
7310
7311         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
7312         found_type = btrfs_file_extent_type(leaf, fi);
7313         if (found_type != BTRFS_FILE_EXTENT_REG &&
7314             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
7315                 /* not a regular extent, must cow */
7316                 goto out;
7317         }
7318
7319         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
7320                 goto out;
7321
7322         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
7323         if (extent_end <= offset)
7324                 goto out;
7325
7326         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7327         if (disk_bytenr == 0)
7328                 goto out;
7329
7330         if (btrfs_file_extent_compression(leaf, fi) ||
7331             btrfs_file_extent_encryption(leaf, fi) ||
7332             btrfs_file_extent_other_encoding(leaf, fi))
7333                 goto out;
7334
7335         /*
7336          * Do the same check as in btrfs_cross_ref_exist but without the
7337          * unnecessary search.
7338          */
7339         if (btrfs_file_extent_generation(leaf, fi) <=
7340             btrfs_root_last_snapshot(&root->root_item))
7341                 goto out;
7342
7343         backref_offset = btrfs_file_extent_offset(leaf, fi);
7344
7345         if (orig_start) {
7346                 *orig_start = key.offset - backref_offset;
7347                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
7348                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
7349         }
7350
7351         if (btrfs_extent_readonly(fs_info, disk_bytenr))
7352                 goto out;
7353
7354         num_bytes = min(offset + *len, extent_end) - offset;
7355         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
7356                 u64 range_end;
7357
7358                 range_end = round_up(offset + num_bytes,
7359                                      root->fs_info->sectorsize) - 1;
7360                 ret = test_range_bit(io_tree, offset, range_end,
7361                                      EXTENT_DELALLOC, 0, NULL);
7362                 if (ret) {
7363                         ret = -EAGAIN;
7364                         goto out;
7365                 }
7366         }
7367
7368         btrfs_release_path(path);
7369
7370         /*
7371          * look for other files referencing this extent, if we
7372          * find any we must cow
7373          */
7374
7375         ret = btrfs_cross_ref_exist(root, btrfs_ino(BTRFS_I(inode)),
7376                                     key.offset - backref_offset, disk_bytenr);
7377         if (ret) {
7378                 ret = 0;
7379                 goto out;
7380         }
7381
7382         /*
7383          * adjust disk_bytenr and num_bytes to cover just the bytes
7384          * in this extent we are about to write.  If there
7385          * are any csums in that range we have to cow in order
7386          * to keep the csums correct
7387          */
7388         disk_bytenr += backref_offset;
7389         disk_bytenr += offset - key.offset;
7390         if (csum_exist_in_range(fs_info, disk_bytenr, num_bytes))
7391                 goto out;
7392         /*
7393          * all of the above have passed, it is safe to overwrite this extent
7394          * without cow
7395          */
7396         *len = num_bytes;
7397         ret = 1;
7398 out:
7399         btrfs_free_path(path);
7400         return ret;
7401 }
7402
7403 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7404                               struct extent_state **cached_state, int writing)
7405 {
7406         struct btrfs_ordered_extent *ordered;
7407         int ret = 0;
7408
7409         while (1) {
7410                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7411                                  cached_state);
7412                 /*
7413                  * We're concerned with the entire range that we're going to be
7414                  * doing DIO to, so we need to make sure there's no ordered
7415                  * extents in this range.
7416                  */
7417                 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), lockstart,
7418                                                      lockend - lockstart + 1);
7419
7420                 /*
7421                  * We need to make sure there are no buffered pages in this
7422                  * range either, we could have raced between the invalidate in
7423                  * generic_file_direct_write and locking the extent.  The
7424                  * invalidate needs to happen so that reads after a write do not
7425                  * get stale data.
7426                  */
7427                 if (!ordered &&
7428                     (!writing || !filemap_range_has_page(inode->i_mapping,
7429                                                          lockstart, lockend)))
7430                         break;
7431
7432                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7433                                      cached_state);
7434
7435                 if (ordered) {
7436                         /*
7437                          * If we are doing a DIO read and the ordered extent we
7438                          * found is for a buffered write, we can not wait for it
7439                          * to complete and retry, because if we do so we can
7440                          * deadlock with concurrent buffered writes on page
7441                          * locks. This happens only if our DIO read covers more
7442                          * than one extent map, if at this point has already
7443                          * created an ordered extent for a previous extent map
7444                          * and locked its range in the inode's io tree, and a
7445                          * concurrent write against that previous extent map's
7446                          * range and this range started (we unlock the ranges
7447                          * in the io tree only when the bios complete and
7448                          * buffered writes always lock pages before attempting
7449                          * to lock range in the io tree).
7450                          */
7451                         if (writing ||
7452                             test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags))
7453                                 btrfs_start_ordered_extent(inode, ordered, 1);
7454                         else
7455                                 ret = -ENOTBLK;
7456                         btrfs_put_ordered_extent(ordered);
7457                 } else {
7458                         /*
7459                          * We could trigger writeback for this range (and wait
7460                          * for it to complete) and then invalidate the pages for
7461                          * this range (through invalidate_inode_pages2_range()),
7462                          * but that can lead us to a deadlock with a concurrent
7463                          * call to readpages() (a buffered read or a defrag call
7464                          * triggered a readahead) on a page lock due to an
7465                          * ordered dio extent we created before but did not have
7466                          * yet a corresponding bio submitted (whence it can not
7467                          * complete), which makes readpages() wait for that
7468                          * ordered extent to complete while holding a lock on
7469                          * that page.
7470                          */
7471                         ret = -ENOTBLK;
7472                 }
7473
7474                 if (ret)
7475                         break;
7476
7477                 cond_resched();
7478         }
7479
7480         return ret;
7481 }
7482
7483 /* The callers of this must take lock_extent() */
7484 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
7485                                        u64 orig_start, u64 block_start,
7486                                        u64 block_len, u64 orig_block_len,
7487                                        u64 ram_bytes, int compress_type,
7488                                        int type)
7489 {
7490         struct extent_map_tree *em_tree;
7491         struct extent_map *em;
7492         struct btrfs_root *root = BTRFS_I(inode)->root;
7493         int ret;
7494
7495         ASSERT(type == BTRFS_ORDERED_PREALLOC ||
7496                type == BTRFS_ORDERED_COMPRESSED ||
7497                type == BTRFS_ORDERED_NOCOW ||
7498                type == BTRFS_ORDERED_REGULAR);
7499
7500         em_tree = &BTRFS_I(inode)->extent_tree;
7501         em = alloc_extent_map();
7502         if (!em)
7503                 return ERR_PTR(-ENOMEM);
7504
7505         em->start = start;
7506         em->orig_start = orig_start;
7507         em->len = len;
7508         em->block_len = block_len;
7509         em->block_start = block_start;
7510         em->bdev = root->fs_info->fs_devices->latest_bdev;
7511         em->orig_block_len = orig_block_len;
7512         em->ram_bytes = ram_bytes;
7513         em->generation = -1;
7514         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7515         if (type == BTRFS_ORDERED_PREALLOC) {
7516                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7517         } else if (type == BTRFS_ORDERED_COMPRESSED) {
7518                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
7519                 em->compress_type = compress_type;
7520         }
7521
7522         do {
7523                 btrfs_drop_extent_cache(BTRFS_I(inode), em->start,
7524                                 em->start + em->len - 1, 0);
7525                 write_lock(&em_tree->lock);
7526                 ret = add_extent_mapping(em_tree, em, 1);
7527                 write_unlock(&em_tree->lock);
7528                 /*
7529                  * The caller has taken lock_extent(), who could race with us
7530                  * to add em?
7531                  */
7532         } while (ret == -EEXIST);
7533
7534         if (ret) {
7535                 free_extent_map(em);
7536                 return ERR_PTR(ret);
7537         }
7538
7539         /* em got 2 refs now, callers needs to do free_extent_map once. */
7540         return em;
7541 }
7542
7543
7544 static int btrfs_get_blocks_direct_read(struct extent_map *em,
7545                                         struct buffer_head *bh_result,
7546                                         struct inode *inode,
7547                                         u64 start, u64 len)
7548 {
7549         if (em->block_start == EXTENT_MAP_HOLE ||
7550                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7551                 return -ENOENT;
7552
7553         len = min(len, em->len - (start - em->start));
7554
7555         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7556                 inode->i_blkbits;
7557         bh_result->b_size = len;
7558         bh_result->b_bdev = em->bdev;
7559         set_buffer_mapped(bh_result);
7560
7561         return 0;
7562 }
7563
7564 static int btrfs_get_blocks_direct_write(struct extent_map **map,
7565                                          struct buffer_head *bh_result,
7566                                          struct inode *inode,
7567                                          struct btrfs_dio_data *dio_data,
7568                                          u64 start, u64 len)
7569 {
7570         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7571         struct extent_map *em = *map;
7572         int ret = 0;
7573
7574         /*
7575          * We don't allocate a new extent in the following cases
7576          *
7577          * 1) The inode is marked as NODATACOW. In this case we'll just use the
7578          * existing extent.
7579          * 2) The extent is marked as PREALLOC. We're good to go here and can
7580          * just use the extent.
7581          *
7582          */
7583         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7584             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7585              em->block_start != EXTENT_MAP_HOLE)) {
7586                 int type;
7587                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7588
7589                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7590                         type = BTRFS_ORDERED_PREALLOC;
7591                 else
7592                         type = BTRFS_ORDERED_NOCOW;
7593                 len = min(len, em->len - (start - em->start));
7594                 block_start = em->block_start + (start - em->start);
7595
7596                 if (can_nocow_extent(inode, start, &len, &orig_start,
7597                                      &orig_block_len, &ram_bytes) == 1 &&
7598                     btrfs_inc_nocow_writers(fs_info, block_start)) {
7599                         struct extent_map *em2;
7600
7601                         em2 = btrfs_create_dio_extent(inode, start, len,
7602                                                       orig_start, block_start,
7603                                                       len, orig_block_len,
7604                                                       ram_bytes, type);
7605                         btrfs_dec_nocow_writers(fs_info, block_start);
7606                         if (type == BTRFS_ORDERED_PREALLOC) {
7607                                 free_extent_map(em);
7608                                 *map = em = em2;
7609                         }
7610
7611                         if (em2 && IS_ERR(em2)) {
7612                                 ret = PTR_ERR(em2);
7613                                 goto out;
7614                         }
7615                         /*
7616                          * For inode marked NODATACOW or extent marked PREALLOC,
7617                          * use the existing or preallocated extent, so does not
7618                          * need to adjust btrfs_space_info's bytes_may_use.
7619                          */
7620                         btrfs_free_reserved_data_space_noquota(inode, start,
7621                                                                len);
7622                         goto skip_cow;
7623                 }
7624         }
7625
7626         /* this will cow the extent */
7627         len = bh_result->b_size;
7628         free_extent_map(em);
7629         *map = em = btrfs_new_extent_direct(inode, start, len);
7630         if (IS_ERR(em)) {
7631                 ret = PTR_ERR(em);
7632                 goto out;
7633         }
7634
7635         len = min(len, em->len - (start - em->start));
7636
7637 skip_cow:
7638         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7639                 inode->i_blkbits;
7640         bh_result->b_size = len;
7641         bh_result->b_bdev = em->bdev;
7642         set_buffer_mapped(bh_result);
7643
7644         if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7645                 set_buffer_new(bh_result);
7646
7647         /*
7648          * Need to update the i_size under the extent lock so buffered
7649          * readers will get the updated i_size when we unlock.
7650          */
7651         if (!dio_data->overwrite && start + len > i_size_read(inode))
7652                 i_size_write(inode, start + len);
7653
7654         WARN_ON(dio_data->reserve < len);
7655         dio_data->reserve -= len;
7656         dio_data->unsubmitted_oe_range_end = start + len;
7657         current->journal_info = dio_data;
7658 out:
7659         return ret;
7660 }
7661
7662 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7663                                    struct buffer_head *bh_result, int create)
7664 {
7665         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7666         struct extent_map *em;
7667         struct extent_state *cached_state = NULL;
7668         struct btrfs_dio_data *dio_data = NULL;
7669         u64 start = iblock << inode->i_blkbits;
7670         u64 lockstart, lockend;
7671         u64 len = bh_result->b_size;
7672         int unlock_bits = EXTENT_LOCKED;
7673         int ret = 0;
7674
7675         if (create)
7676                 unlock_bits |= EXTENT_DIRTY;
7677         else
7678                 len = min_t(u64, len, fs_info->sectorsize);
7679
7680         lockstart = start;
7681         lockend = start + len - 1;
7682
7683         if (current->journal_info) {
7684                 /*
7685                  * Need to pull our outstanding extents and set journal_info to NULL so
7686                  * that anything that needs to check if there's a transaction doesn't get
7687                  * confused.
7688                  */
7689                 dio_data = current->journal_info;
7690                 current->journal_info = NULL;
7691         }
7692
7693         /*
7694          * If this errors out it's because we couldn't invalidate pagecache for
7695          * this range and we need to fallback to buffered.
7696          */
7697         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
7698                                create)) {
7699                 ret = -ENOTBLK;
7700                 goto err;
7701         }
7702
7703         em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len, 0);
7704         if (IS_ERR(em)) {
7705                 ret = PTR_ERR(em);
7706                 goto unlock_err;
7707         }
7708
7709         /*
7710          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7711          * io.  INLINE is special, and we could probably kludge it in here, but
7712          * it's still buffered so for safety lets just fall back to the generic
7713          * buffered path.
7714          *
7715          * For COMPRESSED we _have_ to read the entire extent in so we can
7716          * decompress it, so there will be buffering required no matter what we
7717          * do, so go ahead and fallback to buffered.
7718          *
7719          * We return -ENOTBLK because that's what makes DIO go ahead and go back
7720          * to buffered IO.  Don't blame me, this is the price we pay for using
7721          * the generic code.
7722          */
7723         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7724             em->block_start == EXTENT_MAP_INLINE) {
7725                 free_extent_map(em);
7726                 ret = -ENOTBLK;
7727                 goto unlock_err;
7728         }
7729
7730         if (create) {
7731                 ret = btrfs_get_blocks_direct_write(&em, bh_result, inode,
7732                                                     dio_data, start, len);
7733                 if (ret < 0)
7734                         goto unlock_err;
7735
7736                 /* clear and unlock the entire range */
7737                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7738                                  unlock_bits, 1, 0, &cached_state);
7739         } else {
7740                 ret = btrfs_get_blocks_direct_read(em, bh_result, inode,
7741                                                    start, len);
7742                 /* Can be negative only if we read from a hole */
7743                 if (ret < 0) {
7744                         ret = 0;
7745                         free_extent_map(em);
7746                         goto unlock_err;
7747                 }
7748                 /*
7749                  * We need to unlock only the end area that we aren't using.
7750                  * The rest is going to be unlocked by the endio routine.
7751                  */
7752                 lockstart = start + bh_result->b_size;
7753                 if (lockstart < lockend) {
7754                         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7755                                          lockend, unlock_bits, 1, 0,
7756                                          &cached_state);
7757                 } else {
7758                         free_extent_state(cached_state);
7759                 }
7760         }
7761
7762         free_extent_map(em);
7763
7764         return 0;
7765
7766 unlock_err:
7767         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7768                          unlock_bits, 1, 0, &cached_state);
7769 err:
7770         if (dio_data)
7771                 current->journal_info = dio_data;
7772         return ret;
7773 }
7774
7775 static inline blk_status_t submit_dio_repair_bio(struct inode *inode,
7776                                                  struct bio *bio,
7777                                                  int mirror_num)
7778 {
7779         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7780         blk_status_t ret;
7781
7782         BUG_ON(bio_op(bio) == REQ_OP_WRITE);
7783
7784         ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DIO_REPAIR);
7785         if (ret)
7786                 return ret;
7787
7788         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
7789
7790         return ret;
7791 }
7792
7793 static int btrfs_check_dio_repairable(struct inode *inode,
7794                                       struct bio *failed_bio,
7795                                       struct io_failure_record *failrec,
7796                                       int failed_mirror)
7797 {
7798         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7799         int num_copies;
7800
7801         num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
7802         if (num_copies == 1) {
7803                 /*
7804                  * we only have a single copy of the data, so don't bother with
7805                  * all the retry and error correction code that follows. no
7806                  * matter what the error is, it is very likely to persist.
7807                  */
7808                 btrfs_debug(fs_info,
7809                         "Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
7810                         num_copies, failrec->this_mirror, failed_mirror);
7811                 return 0;
7812         }
7813
7814         failrec->failed_mirror = failed_mirror;
7815         failrec->this_mirror++;
7816         if (failrec->this_mirror == failed_mirror)
7817                 failrec->this_mirror++;
7818
7819         if (failrec->this_mirror > num_copies) {
7820                 btrfs_debug(fs_info,
7821                         "Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
7822                         num_copies, failrec->this_mirror, failed_mirror);
7823                 return 0;
7824         }
7825
7826         return 1;
7827 }
7828
7829 static blk_status_t dio_read_error(struct inode *inode, struct bio *failed_bio,
7830                                    struct page *page, unsigned int pgoff,
7831                                    u64 start, u64 end, int failed_mirror,
7832                                    bio_end_io_t *repair_endio, void *repair_arg)
7833 {
7834         struct io_failure_record *failrec;
7835         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7836         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
7837         struct bio *bio;
7838         int isector;
7839         unsigned int read_mode = 0;
7840         int segs;
7841         int ret;
7842         blk_status_t status;
7843         struct bio_vec bvec;
7844
7845         BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
7846
7847         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7848         if (ret)
7849                 return errno_to_blk_status(ret);
7850
7851         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7852                                          failed_mirror);
7853         if (!ret) {
7854                 free_io_failure(failure_tree, io_tree, failrec);
7855                 return BLK_STS_IOERR;
7856         }
7857
7858         segs = bio_segments(failed_bio);
7859         bio_get_first_bvec(failed_bio, &bvec);
7860         if (segs > 1 ||
7861             (bvec.bv_len > btrfs_inode_sectorsize(inode)))
7862                 read_mode |= REQ_FAILFAST_DEV;
7863
7864         isector = start - btrfs_io_bio(failed_bio)->logical;
7865         isector >>= inode->i_sb->s_blocksize_bits;
7866         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7867                                 pgoff, isector, repair_endio, repair_arg);
7868         bio_set_op_attrs(bio, REQ_OP_READ, read_mode);
7869
7870         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7871                     "repair DIO read error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d",
7872                     read_mode, failrec->this_mirror, failrec->in_validation);
7873
7874         status = submit_dio_repair_bio(inode, bio, failrec->this_mirror);
7875         if (status) {
7876                 free_io_failure(failure_tree, io_tree, failrec);
7877                 bio_put(bio);
7878         }
7879
7880         return status;
7881 }
7882
7883 struct btrfs_retry_complete {
7884         struct completion done;
7885         struct inode *inode;
7886         u64 start;
7887         int uptodate;
7888 };
7889
7890 static void btrfs_retry_endio_nocsum(struct bio *bio)
7891 {
7892         struct btrfs_retry_complete *done = bio->bi_private;
7893         struct inode *inode = done->inode;
7894         struct bio_vec *bvec;
7895         struct extent_io_tree *io_tree, *failure_tree;
7896         int i;
7897
7898         if (bio->bi_status)
7899                 goto end;
7900
7901         ASSERT(bio->bi_vcnt == 1);
7902         io_tree = &BTRFS_I(inode)->io_tree;
7903         failure_tree = &BTRFS_I(inode)->io_failure_tree;
7904         ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(inode));
7905
7906         done->uptodate = 1;
7907         ASSERT(!bio_flagged(bio, BIO_CLONED));
7908         bio_for_each_segment_all(bvec, bio, i)
7909                 clean_io_failure(BTRFS_I(inode)->root->fs_info, failure_tree,
7910                                  io_tree, done->start, bvec->bv_page,
7911                                  btrfs_ino(BTRFS_I(inode)), 0);
7912 end:
7913         complete(&done->done);
7914         bio_put(bio);
7915 }
7916
7917 static blk_status_t __btrfs_correct_data_nocsum(struct inode *inode,
7918                                                 struct btrfs_io_bio *io_bio)
7919 {
7920         struct btrfs_fs_info *fs_info;
7921         struct bio_vec bvec;
7922         struct bvec_iter iter;
7923         struct btrfs_retry_complete done;
7924         u64 start;
7925         unsigned int pgoff;
7926         u32 sectorsize;
7927         int nr_sectors;
7928         blk_status_t ret;
7929         blk_status_t err = BLK_STS_OK;
7930
7931         fs_info = BTRFS_I(inode)->root->fs_info;
7932         sectorsize = fs_info->sectorsize;
7933
7934         start = io_bio->logical;
7935         done.inode = inode;
7936         io_bio->bio.bi_iter = io_bio->iter;
7937
7938         bio_for_each_segment(bvec, &io_bio->bio, iter) {
7939                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);
7940                 pgoff = bvec.bv_offset;
7941
7942 next_block_or_try_again:
7943                 done.uptodate = 0;
7944                 done.start = start;
7945                 init_completion(&done.done);
7946
7947                 ret = dio_read_error(inode, &io_bio->bio, bvec.bv_page,
7948                                 pgoff, start, start + sectorsize - 1,
7949                                 io_bio->mirror_num,
7950                                 btrfs_retry_endio_nocsum, &done);
7951                 if (ret) {
7952                         err = ret;
7953                         goto next;
7954                 }
7955
7956                 wait_for_completion_io(&done.done);
7957
7958                 if (!done.uptodate) {
7959                         /* We might have another mirror, so try again */
7960                         goto next_block_or_try_again;
7961                 }
7962
7963 next:
7964                 start += sectorsize;
7965
7966                 nr_sectors--;
7967                 if (nr_sectors) {
7968                         pgoff += sectorsize;
7969                         ASSERT(pgoff < PAGE_SIZE);
7970                         goto next_block_or_try_again;
7971                 }
7972         }
7973
7974         return err;
7975 }
7976
7977 static void btrfs_retry_endio(struct bio *bio)
7978 {
7979         struct btrfs_retry_complete *done = bio->bi_private;
7980         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7981         struct extent_io_tree *io_tree, *failure_tree;
7982         struct inode *inode = done->inode;
7983         struct bio_vec *bvec;
7984         int uptodate;
7985         int ret;
7986         int i;
7987
7988         if (bio->bi_status)
7989                 goto end;
7990
7991         uptodate = 1;
7992
7993         ASSERT(bio->bi_vcnt == 1);
7994         ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(done->inode));
7995
7996         io_tree = &BTRFS_I(inode)->io_tree;
7997         failure_tree = &BTRFS_I(inode)->io_failure_tree;
7998
7999         ASSERT(!bio_flagged(bio, BIO_CLONED));
8000         bio_for_each_segment_all(bvec, bio, i) {
8001                 ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,
8002                                              bvec->bv_offset, done->start,
8003                                              bvec->bv_len);
8004                 if (!ret)
8005                         clean_io_failure(BTRFS_I(inode)->root->fs_info,
8006                                          failure_tree, io_tree, done->start,
8007                                          bvec->bv_page,
8008                                          btrfs_ino(BTRFS_I(inode)),
8009                                          bvec->bv_offset);
8010                 else
8011                         uptodate = 0;
8012         }
8013
8014         done->uptodate = uptodate;
8015 end:
8016         complete(&done->done);
8017         bio_put(bio);
8018 }
8019
8020 static blk_status_t __btrfs_subio_endio_read(struct inode *inode,
8021                 struct btrfs_io_bio *io_bio, blk_status_t err)
8022 {
8023         struct btrfs_fs_info *fs_info;
8024         struct bio_vec bvec;
8025         struct bvec_iter iter;
8026         struct btrfs_retry_complete done;
8027         u64 start;
8028         u64 offset = 0;
8029         u32 sectorsize;
8030         int nr_sectors;
8031         unsigned int pgoff;
8032         int csum_pos;
8033         bool uptodate = (err == 0);
8034         int ret;
8035         blk_status_t status;
8036
8037         fs_info = BTRFS_I(inode)->root->fs_info;
8038         sectorsize = fs_info->sectorsize;
8039
8040         err = BLK_STS_OK;
8041         start = io_bio->logical;
8042         done.inode = inode;
8043         io_bio->bio.bi_iter = io_bio->iter;
8044
8045         bio_for_each_segment(bvec, &io_bio->bio, iter) {
8046                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);
8047
8048                 pgoff = bvec.bv_offset;
8049 next_block:
8050                 if (uptodate) {
8051                         csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);
8052                         ret = __readpage_endio_check(inode, io_bio, csum_pos,
8053                                         bvec.bv_page, pgoff, start, sectorsize);
8054                         if (likely(!ret))
8055                                 goto next;
8056                 }
8057 try_again:
8058                 done.uptodate = 0;
8059                 done.start = start;
8060                 init_completion(&done.done);
8061
8062                 status = dio_read_error(inode, &io_bio->bio, bvec.bv_page,
8063                                         pgoff, start, start + sectorsize - 1,
8064                                         io_bio->mirror_num, btrfs_retry_endio,
8065                                         &done);
8066                 if (status) {
8067                         err = status;
8068                         goto next;
8069                 }
8070
8071                 wait_for_completion_io(&done.done);
8072
8073                 if (!done.uptodate) {
8074                         /* We might have another mirror, so try again */
8075                         goto try_again;
8076                 }
8077 next:
8078                 offset += sectorsize;
8079                 start += sectorsize;
8080
8081                 ASSERT(nr_sectors);
8082
8083                 nr_sectors--;
8084                 if (nr_sectors) {
8085                         pgoff += sectorsize;
8086                         ASSERT(pgoff < PAGE_SIZE);
8087                         goto next_block;
8088                 }
8089         }
8090
8091         return err;
8092 }
8093
8094 static blk_status_t btrfs_subio_endio_read(struct inode *inode,
8095                 struct btrfs_io_bio *io_bio, blk_status_t err)
8096 {
8097         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8098
8099         if (skip_csum) {
8100                 if (unlikely(err))
8101                         return __btrfs_correct_data_nocsum(inode, io_bio);
8102                 else
8103                         return BLK_STS_OK;
8104         } else {
8105                 return __btrfs_subio_endio_read(inode, io_bio, err);
8106         }
8107 }
8108
8109 static void btrfs_endio_direct_read(struct bio *bio)
8110 {
8111         struct btrfs_dio_private *dip = bio->bi_private;
8112         struct inode *inode = dip->inode;
8113         struct bio *dio_bio;
8114         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8115         blk_status_t err = bio->bi_status;
8116
8117         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
8118                 err = btrfs_subio_endio_read(inode, io_bio, err);
8119
8120         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
8121                       dip->logical_offset + dip->bytes - 1);
8122         dio_bio = dip->dio_bio;
8123
8124         kfree(dip);
8125
8126         dio_bio->bi_status = err;
8127         dio_end_io(dio_bio);
8128
8129         if (io_bio->end_io)
8130                 io_bio->end_io(io_bio, blk_status_to_errno(err));
8131         bio_put(bio);
8132 }
8133
8134 static void __endio_write_update_ordered(struct inode *inode,
8135                                          const u64 offset, const u64 bytes,
8136                                          const bool uptodate)
8137 {
8138         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8139         struct btrfs_ordered_extent *ordered = NULL;
8140         struct btrfs_workqueue *wq;
8141         btrfs_work_func_t func;
8142         u64 ordered_offset = offset;
8143         u64 ordered_bytes = bytes;
8144         u64 last_offset;
8145
8146         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
8147                 wq = fs_info->endio_freespace_worker;
8148                 func = btrfs_freespace_write_helper;
8149         } else {
8150                 wq = fs_info->endio_write_workers;
8151                 func = btrfs_endio_write_helper;
8152         }
8153
8154         while (ordered_offset < offset + bytes) {
8155                 last_offset = ordered_offset;
8156                 if (btrfs_dec_test_first_ordered_pending(inode, &ordered,
8157                                                            &ordered_offset,
8158                                                            ordered_bytes,
8159                                                            uptodate)) {
8160                         btrfs_init_work(&ordered->work, func,
8161                                         finish_ordered_fn,
8162                                         NULL, NULL);
8163                         btrfs_queue_work(wq, &ordered->work);
8164                 }
8165                 /*
8166                  * If btrfs_dec_test_ordered_pending does not find any ordered
8167                  * extent in the range, we can exit.
8168                  */
8169                 if (ordered_offset == last_offset)
8170                         return;
8171                 /*
8172                  * Our bio might span multiple ordered extents. In this case
8173                  * we keep goin until we have accounted the whole dio.
8174                  */
8175                 if (ordered_offset < offset + bytes) {
8176                         ordered_bytes = offset + bytes - ordered_offset;
8177                         ordered = NULL;
8178                 }
8179         }
8180 }
8181
8182 static void btrfs_endio_direct_write(struct bio *bio)
8183 {
8184         struct btrfs_dio_private *dip = bio->bi_private;
8185         struct bio *dio_bio = dip->dio_bio;
8186
8187         __endio_write_update_ordered(dip->inode, dip->logical_offset,
8188                                      dip->bytes, !bio->bi_status);
8189
8190         kfree(dip);
8191
8192         dio_bio->bi_status = bio->bi_status;
8193         dio_end_io(dio_bio);
8194         bio_put(bio);
8195 }
8196
8197 static blk_status_t btrfs_submit_bio_start_direct_io(void *private_data,
8198                                     struct bio *bio, u64 offset)
8199 {
8200         struct inode *inode = private_data;
8201         blk_status_t ret;
8202         ret = btrfs_csum_one_bio(inode, bio, offset, 1);
8203         BUG_ON(ret); /* -ENOMEM */
8204         return 0;
8205 }
8206
8207 static void btrfs_end_dio_bio(struct bio *bio)
8208 {
8209         struct btrfs_dio_private *dip = bio->bi_private;
8210         blk_status_t err = bio->bi_status;
8211
8212         if (err)
8213                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
8214                            "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
8215                            btrfs_ino(BTRFS_I(dip->inode)), bio_op(bio),
8216                            bio->bi_opf,
8217                            (unsigned long long)bio->bi_iter.bi_sector,
8218                            bio->bi_iter.bi_size, err);
8219
8220         if (dip->subio_endio)
8221                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
8222
8223         if (err) {
8224                 /*
8225                  * We want to perceive the errors flag being set before
8226                  * decrementing the reference count. We don't need a barrier
8227                  * since atomic operations with a return value are fully
8228                  * ordered as per atomic_t.txt
8229                  */
8230                 dip->errors = 1;
8231         }
8232
8233         /* if there are more bios still pending for this dio, just exit */
8234         if (!atomic_dec_and_test(&dip->pending_bios))
8235                 goto out;
8236
8237         if (dip->errors) {
8238                 bio_io_error(dip->orig_bio);
8239         } else {
8240                 dip->dio_bio->bi_status = BLK_STS_OK;
8241                 bio_endio(dip->orig_bio);
8242         }
8243 out:
8244         bio_put(bio);
8245 }
8246
8247 static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode,
8248                                                  struct btrfs_dio_private *dip,
8249                                                  struct bio *bio,
8250                                                  u64 file_offset)
8251 {
8252         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8253         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
8254         blk_status_t ret;
8255
8256         /*
8257          * We load all the csum data we need when we submit
8258          * the first bio to reduce the csum tree search and
8259          * contention.
8260          */
8261         if (dip->logical_offset == file_offset) {
8262                 ret = btrfs_lookup_bio_sums_dio(inode, dip->orig_bio,
8263                                                 file_offset);
8264                 if (ret)
8265                         return ret;
8266         }
8267
8268         if (bio == dip->orig_bio)
8269                 return 0;
8270
8271         file_offset -= dip->logical_offset;
8272         file_offset >>= inode->i_sb->s_blocksize_bits;
8273         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
8274
8275         return 0;
8276 }
8277
8278 static inline blk_status_t btrfs_submit_dio_bio(struct bio *bio,
8279                 struct inode *inode, u64 file_offset, int async_submit)
8280 {
8281         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8282         struct btrfs_dio_private *dip = bio->bi_private;
8283         bool write = bio_op(bio) == REQ_OP_WRITE;
8284         blk_status_t ret;
8285
8286         /* Check btrfs_submit_bio_hook() for rules about async submit. */
8287         if (async_submit)
8288                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
8289
8290         if (!write) {
8291                 ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA);
8292                 if (ret)
8293                         goto err;
8294         }
8295
8296         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
8297                 goto map;
8298
8299         if (write && async_submit) {
8300                 ret = btrfs_wq_submit_bio(fs_info, bio, 0, 0,
8301                                           file_offset, inode,
8302                                           btrfs_submit_bio_start_direct_io,
8303                                           btrfs_submit_bio_done);
8304                 goto err;
8305         } else if (write) {
8306                 /*
8307                  * If we aren't doing async submit, calculate the csum of the
8308                  * bio now.
8309                  */
8310                 ret = btrfs_csum_one_bio(inode, bio, file_offset, 1);
8311                 if (ret)
8312                         goto err;
8313         } else {
8314                 ret = btrfs_lookup_and_bind_dio_csum(inode, dip, bio,
8315                                                      file_offset);
8316                 if (ret)
8317                         goto err;
8318         }
8319 map:
8320         ret = btrfs_map_bio(fs_info, bio, 0, 0);
8321 err:
8322         return ret;
8323 }
8324
8325 static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip)
8326 {
8327         struct inode *inode = dip->inode;
8328         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8329         struct bio *bio;
8330         struct bio *orig_bio = dip->orig_bio;
8331         u64 start_sector = orig_bio->bi_iter.bi_sector;
8332         u64 file_offset = dip->logical_offset;
8333         u64 map_length;
8334         int async_submit = 0;
8335         u64 submit_len;
8336         int clone_offset = 0;
8337         int clone_len;
8338         int ret;
8339         blk_status_t status;
8340
8341         map_length = orig_bio->bi_iter.bi_size;
8342         submit_len = map_length;
8343         ret = btrfs_map_block(fs_info, btrfs_op(orig_bio), start_sector << 9,
8344                               &map_length, NULL, 0);
8345         if (ret)
8346                 return -EIO;
8347
8348         if (map_length >= submit_len) {
8349                 bio = orig_bio;
8350                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
8351                 goto submit;
8352         }
8353
8354         /* async crcs make it difficult to collect full stripe writes. */
8355         if (btrfs_data_alloc_profile(fs_info) & BTRFS_BLOCK_GROUP_RAID56_MASK)
8356                 async_submit = 0;
8357         else
8358                 async_submit = 1;
8359
8360         /* bio split */
8361         ASSERT(map_length <= INT_MAX);
8362         atomic_inc(&dip->pending_bios);
8363         do {
8364                 clone_len = min_t(int, submit_len, map_length);
8365
8366                 /*
8367                  * This will never fail as it's passing GPF_NOFS and
8368                  * the allocation is backed by btrfs_bioset.
8369                  */
8370                 bio = btrfs_bio_clone_partial(orig_bio, clone_offset,
8371                                               clone_len);
8372                 bio->bi_private = dip;
8373                 bio->bi_end_io = btrfs_end_dio_bio;
8374                 btrfs_io_bio(bio)->logical = file_offset;
8375
8376                 ASSERT(submit_len >= clone_len);
8377                 submit_len -= clone_len;
8378                 if (submit_len == 0)
8379                         break;
8380
8381                 /*
8382                  * Increase the count before we submit the bio so we know
8383                  * the end IO handler won't happen before we increase the
8384                  * count. Otherwise, the dip might get freed before we're
8385                  * done setting it up.
8386                  */
8387                 atomic_inc(&dip->pending_bios);
8388
8389                 status = btrfs_submit_dio_bio(bio, inode, file_offset,
8390                                                 async_submit);
8391                 if (status) {
8392                         bio_put(bio);
8393                         atomic_dec(&dip->pending_bios);
8394                         goto out_err;
8395                 }
8396
8397                 clone_offset += clone_len;
8398                 start_sector += clone_len >> 9;
8399                 file_offset += clone_len;
8400
8401                 map_length = submit_len;
8402                 ret = btrfs_map_block(fs_info, btrfs_op(orig_bio),
8403                                       start_sector << 9, &map_length, NULL, 0);
8404                 if (ret)
8405                         goto out_err;
8406         } while (submit_len > 0);
8407
8408 submit:
8409         status = btrfs_submit_dio_bio(bio, inode, file_offset, async_submit);
8410         if (!status)
8411                 return 0;
8412
8413         bio_put(bio);
8414 out_err:
8415         dip->errors = 1;
8416         /*
8417          * Before atomic variable goto zero, we must  make sure dip->errors is
8418          * perceived to be set. This ordering is ensured by the fact that an
8419          * atomic operations with a return value are fully ordered as per
8420          * atomic_t.txt
8421          */
8422         if (atomic_dec_and_test(&dip->pending_bios))
8423                 bio_io_error(dip->orig_bio);
8424
8425         /* bio_end_io() will handle error, so we needn't return it */
8426         return 0;
8427 }
8428
8429 static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
8430                                 loff_t file_offset)
8431 {
8432         struct btrfs_dio_private *dip = NULL;
8433         struct bio *bio = NULL;
8434         struct btrfs_io_bio *io_bio;
8435         bool write = (bio_op(dio_bio) == REQ_OP_WRITE);
8436         int ret = 0;
8437
8438         bio = btrfs_bio_clone(dio_bio);
8439
8440         dip = kzalloc(sizeof(*dip), GFP_NOFS);
8441         if (!dip) {
8442                 ret = -ENOMEM;
8443                 goto free_ordered;
8444         }
8445
8446         dip->private = dio_bio->bi_private;
8447         dip->inode = inode;
8448         dip->logical_offset = file_offset;
8449         dip->bytes = dio_bio->bi_iter.bi_size;
8450         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
8451         bio->bi_private = dip;
8452         dip->orig_bio = bio;
8453         dip->dio_bio = dio_bio;
8454         atomic_set(&dip->pending_bios, 0);
8455         io_bio = btrfs_io_bio(bio);
8456         io_bio->logical = file_offset;
8457
8458         if (write) {
8459                 bio->bi_end_io = btrfs_endio_direct_write;
8460         } else {
8461                 bio->bi_end_io = btrfs_endio_direct_read;
8462                 dip->subio_endio = btrfs_subio_endio_read;
8463         }
8464
8465         /*
8466          * Reset the range for unsubmitted ordered extents (to a 0 length range)
8467          * even if we fail to submit a bio, because in such case we do the
8468          * corresponding error handling below and it must not be done a second
8469          * time by btrfs_direct_IO().
8470          */
8471         if (write) {
8472                 struct btrfs_dio_data *dio_data = current->journal_info;
8473
8474                 dio_data->unsubmitted_oe_range_end = dip->logical_offset +
8475                         dip->bytes;
8476                 dio_data->unsubmitted_oe_range_start =
8477                         dio_data->unsubmitted_oe_range_end;
8478         }
8479
8480         ret = btrfs_submit_direct_hook(dip);
8481         if (!ret)
8482                 return;
8483
8484         if (io_bio->end_io)
8485                 io_bio->end_io(io_bio, ret);
8486
8487 free_ordered:
8488         /*
8489          * If we arrived here it means either we failed to submit the dip
8490          * or we either failed to clone the dio_bio or failed to allocate the
8491          * dip. If we cloned the dio_bio and allocated the dip, we can just
8492          * call bio_endio against our io_bio so that we get proper resource
8493          * cleanup if we fail to submit the dip, otherwise, we must do the
8494          * same as btrfs_endio_direct_[write|read] because we can't call these
8495          * callbacks - they require an allocated dip and a clone of dio_bio.
8496          */
8497         if (bio && dip) {
8498                 bio_io_error(bio);
8499                 /*
8500                  * The end io callbacks free our dip, do the final put on bio
8501                  * and all the cleanup and final put for dio_bio (through
8502                  * dio_end_io()).
8503                  */
8504                 dip = NULL;
8505                 bio = NULL;
8506         } else {
8507                 if (write)
8508                         __endio_write_update_ordered(inode,
8509                                                 file_offset,
8510                                                 dio_bio->bi_iter.bi_size,
8511                                                 false);
8512                 else
8513                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
8514                               file_offset + dio_bio->bi_iter.bi_size - 1);
8515
8516                 dio_bio->bi_status = BLK_STS_IOERR;
8517                 /*
8518                  * Releases and cleans up our dio_bio, no need to bio_put()
8519                  * nor bio_endio()/bio_io_error() against dio_bio.
8520                  */
8521                 dio_end_io(dio_bio);
8522         }
8523         if (bio)
8524                 bio_put(bio);
8525         kfree(dip);
8526 }
8527
8528 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
8529                                const struct iov_iter *iter, loff_t offset)
8530 {
8531         int seg;
8532         int i;
8533         unsigned int blocksize_mask = fs_info->sectorsize - 1;
8534         ssize_t retval = -EINVAL;
8535
8536         if (offset & blocksize_mask)
8537                 goto out;
8538
8539         if (iov_iter_alignment(iter) & blocksize_mask)
8540                 goto out;
8541
8542         /* If this is a write we don't need to check anymore */
8543         if (iov_iter_rw(iter) != READ || !iter_is_iovec(iter))
8544                 return 0;
8545         /*
8546          * Check to make sure we don't have duplicate iov_base's in this
8547          * iovec, if so return EINVAL, otherwise we'll get csum errors
8548          * when reading back.
8549          */
8550         for (seg = 0; seg < iter->nr_segs; seg++) {
8551                 for (i = seg + 1; i < iter->nr_segs; i++) {
8552                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8553                                 goto out;
8554                 }
8555         }
8556         retval = 0;
8557 out:
8558         return retval;
8559 }
8560
8561 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
8562 {
8563         struct file *file = iocb->ki_filp;
8564         struct inode *inode = file->f_mapping->host;
8565         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8566         struct btrfs_dio_data dio_data = { 0 };
8567         struct extent_changeset *data_reserved = NULL;
8568         loff_t offset = iocb->ki_pos;
8569         size_t count = 0;
8570         int flags = 0;
8571         bool wakeup = true;
8572         bool relock = false;
8573         ssize_t ret;
8574
8575         if (check_direct_IO(fs_info, iter, offset))
8576                 return 0;
8577
8578         inode_dio_begin(inode);
8579
8580         /*
8581          * The generic stuff only does filemap_write_and_wait_range, which
8582          * isn't enough if we've written compressed pages to this area, so
8583          * we need to flush the dirty pages again to make absolutely sure
8584          * that any outstanding dirty pages are on disk.
8585          */
8586         count = iov_iter_count(iter);
8587         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8588                      &BTRFS_I(inode)->runtime_flags))
8589                 filemap_fdatawrite_range(inode->i_mapping, offset,
8590                                          offset + count - 1);
8591
8592         if (iov_iter_rw(iter) == WRITE) {
8593                 /*
8594                  * If the write DIO is beyond the EOF, we need update
8595                  * the isize, but it is protected by i_mutex. So we can
8596                  * not unlock the i_mutex at this case.
8597                  */
8598                 if (offset + count <= inode->i_size) {
8599                         dio_data.overwrite = 1;
8600                         inode_unlock(inode);
8601                         relock = true;
8602                 } else if (iocb->ki_flags & IOCB_NOWAIT) {
8603                         ret = -EAGAIN;
8604                         goto out;
8605                 }
8606                 ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
8607                                                    offset, count);
8608                 if (ret)
8609                         goto out;
8610
8611                 /*
8612                  * We need to know how many extents we reserved so that we can
8613                  * do the accounting properly if we go over the number we
8614                  * originally calculated.  Abuse current->journal_info for this.
8615                  */
8616                 dio_data.reserve = round_up(count,
8617                                             fs_info->sectorsize);
8618                 dio_data.unsubmitted_oe_range_start = (u64)offset;
8619                 dio_data.unsubmitted_oe_range_end = (u64)offset;
8620                 current->journal_info = &dio_data;
8621                 down_read(&BTRFS_I(inode)->dio_sem);
8622         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8623                                      &BTRFS_I(inode)->runtime_flags)) {
8624                 inode_dio_end(inode);
8625                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8626                 wakeup = false;
8627         }
8628
8629         ret = __blockdev_direct_IO(iocb, inode,
8630                                    fs_info->fs_devices->latest_bdev,
8631                                    iter, btrfs_get_blocks_direct, NULL,
8632                                    btrfs_submit_direct, flags);
8633         if (iov_iter_rw(iter) == WRITE) {
8634                 up_read(&BTRFS_I(inode)->dio_sem);
8635                 current->journal_info = NULL;
8636                 if (ret < 0 && ret != -EIOCBQUEUED) {
8637                         if (dio_data.reserve)
8638                                 btrfs_delalloc_release_space(inode, data_reserved,
8639                                         offset, dio_data.reserve, true);
8640                         /*
8641                          * On error we might have left some ordered extents
8642                          * without submitting corresponding bios for them, so
8643                          * cleanup them up to avoid other tasks getting them
8644                          * and waiting for them to complete forever.
8645                          */
8646                         if (dio_data.unsubmitted_oe_range_start <
8647                             dio_data.unsubmitted_oe_range_end)
8648                                 __endio_write_update_ordered(inode,
8649                                         dio_data.unsubmitted_oe_range_start,
8650                                         dio_data.unsubmitted_oe_range_end -
8651                                         dio_data.unsubmitted_oe_range_start,
8652                                         false);
8653                 } else if (ret >= 0 && (size_t)ret < count)
8654                         btrfs_delalloc_release_space(inode, data_reserved,
8655                                         offset, count - (size_t)ret, true);
8656                 btrfs_delalloc_release_extents(BTRFS_I(inode), count, false);
8657         }
8658 out:
8659         if (wakeup)
8660                 inode_dio_end(inode);
8661         if (relock)
8662                 inode_lock(inode);
8663
8664         extent_changeset_free(data_reserved);
8665         return ret;
8666 }
8667
8668 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8669
8670 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8671                 __u64 start, __u64 len)
8672 {
8673         int     ret;
8674
8675         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8676         if (ret)
8677                 return ret;
8678
8679         return extent_fiemap(inode, fieinfo, start, len);
8680 }
8681
8682 int btrfs_readpage(struct file *file, struct page *page)
8683 {
8684         struct extent_io_tree *tree;
8685         tree = &BTRFS_I(page->mapping->host)->io_tree;
8686         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8687 }
8688
8689 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8690 {
8691         struct inode *inode = page->mapping->host;
8692         int ret;
8693
8694         if (current->flags & PF_MEMALLOC) {
8695                 redirty_page_for_writepage(wbc, page);
8696                 unlock_page(page);
8697                 return 0;
8698         }
8699
8700         /*
8701          * If we are under memory pressure we will call this directly from the
8702          * VM, we need to make sure we have the inode referenced for the ordered
8703          * extent.  If not just return like we didn't do anything.
8704          */
8705         if (!igrab(inode)) {
8706                 redirty_page_for_writepage(wbc, page);
8707                 return AOP_WRITEPAGE_ACTIVATE;
8708         }
8709         ret = extent_write_full_page(page, wbc);
8710         btrfs_add_delayed_iput(inode);
8711         return ret;
8712 }
8713
8714 static int btrfs_writepages(struct address_space *mapping,
8715                             struct writeback_control *wbc)
8716 {
8717         return extent_writepages(mapping, wbc);
8718 }
8719
8720 static int
8721 btrfs_readpages(struct file *file, struct address_space *mapping,
8722                 struct list_head *pages, unsigned nr_pages)
8723 {
8724         return extent_readpages(mapping, pages, nr_pages);
8725 }
8726
8727 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8728 {
8729         int ret = try_release_extent_mapping(page, gfp_flags);
8730         if (ret == 1) {
8731                 ClearPagePrivate(page);
8732                 set_page_private(page, 0);
8733                 put_page(page);
8734         }
8735         return ret;
8736 }
8737
8738 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8739 {
8740         if (PageWriteback(page) || PageDirty(page))
8741                 return 0;
8742         return __btrfs_releasepage(page, gfp_flags);
8743 }
8744
8745 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8746                                  unsigned int length)
8747 {
8748         struct inode *inode = page->mapping->host;
8749         struct extent_io_tree *tree;
8750         struct btrfs_ordered_extent *ordered;
8751         struct extent_state *cached_state = NULL;
8752         u64 page_start = page_offset(page);
8753         u64 page_end = page_start + PAGE_SIZE - 1;
8754         u64 start;
8755         u64 end;
8756         int inode_evicting = inode->i_state & I_FREEING;
8757
8758         /*
8759          * we have the page locked, so new writeback can't start,
8760          * and the dirty bit won't be cleared while we are here.
8761          *
8762          * Wait for IO on this page so that we can safely clear
8763          * the PagePrivate2 bit and do ordered accounting
8764          */
8765         wait_on_page_writeback(page);
8766
8767         tree = &BTRFS_I(inode)->io_tree;
8768         if (offset) {
8769                 btrfs_releasepage(page, GFP_NOFS);
8770                 return;
8771         }
8772
8773         if (!inode_evicting)
8774                 lock_extent_bits(tree, page_start, page_end, &cached_state);
8775 again:
8776         start = page_start;
8777         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
8778                                         page_end - start + 1);
8779         if (ordered) {
8780                 end = min(page_end, ordered->file_offset + ordered->len - 1);
8781                 /*
8782                  * IO on this page will never be started, so we need
8783                  * to account for any ordered extents now
8784                  */
8785                 if (!inode_evicting)
8786                         clear_extent_bit(tree, start, end,
8787                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8788                                          EXTENT_DELALLOC_NEW |
8789                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8790                                          EXTENT_DEFRAG, 1, 0, &cached_state);
8791                 /*
8792                  * whoever cleared the private bit is responsible
8793                  * for the finish_ordered_io
8794                  */
8795                 if (TestClearPagePrivate2(page)) {
8796                         struct btrfs_ordered_inode_tree *tree;
8797                         u64 new_len;
8798
8799                         tree = &BTRFS_I(inode)->ordered_tree;
8800
8801                         spin_lock_irq(&tree->lock);
8802                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8803                         new_len = start - ordered->file_offset;
8804                         if (new_len < ordered->truncated_len)
8805                                 ordered->truncated_len = new_len;
8806                         spin_unlock_irq(&tree->lock);
8807
8808                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8809                                                            start,
8810                                                            end - start + 1, 1))
8811                                 btrfs_finish_ordered_io(ordered);
8812                 }
8813                 btrfs_put_ordered_extent(ordered);
8814                 if (!inode_evicting) {
8815                         cached_state = NULL;
8816                         lock_extent_bits(tree, start, end,
8817                                          &cached_state);
8818                 }
8819
8820                 start = end + 1;
8821                 if (start < page_end)
8822                         goto again;
8823         }
8824
8825         /*
8826          * Qgroup reserved space handler
8827          * Page here will be either
8828          * 1) Already written to disk
8829          *    In this case, its reserved space is released from data rsv map
8830          *    and will be freed by delayed_ref handler finally.
8831          *    So even we call qgroup_free_data(), it won't decrease reserved
8832          *    space.
8833          * 2) Not written to disk
8834          *    This means the reserved space should be freed here. However,
8835          *    if a truncate invalidates the page (by clearing PageDirty)
8836          *    and the page is accounted for while allocating extent
8837          *    in btrfs_check_data_free_space() we let delayed_ref to
8838          *    free the entire extent.
8839          */
8840         if (PageDirty(page))
8841                 btrfs_qgroup_free_data(inode, NULL, page_start, PAGE_SIZE);
8842         if (!inode_evicting) {
8843                 clear_extent_bit(tree, page_start, page_end,
8844                                  EXTENT_LOCKED | EXTENT_DIRTY |
8845                                  EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
8846                                  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 1, 1,
8847                                  &cached_state);
8848
8849                 __btrfs_releasepage(page, GFP_NOFS);
8850         }
8851
8852         ClearPageChecked(page);
8853         if (PagePrivate(page)) {
8854                 ClearPagePrivate(page);
8855                 set_page_private(page, 0);
8856                 put_page(page);
8857         }
8858 }
8859
8860 /*
8861  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8862  * called from a page fault handler when a page is first dirtied. Hence we must
8863  * be careful to check for EOF conditions here. We set the page up correctly
8864  * for a written page which means we get ENOSPC checking when writing into
8865  * holes and correct delalloc and unwritten extent mapping on filesystems that
8866  * support these features.
8867  *
8868  * We are not allowed to take the i_mutex here so we have to play games to
8869  * protect against truncate races as the page could now be beyond EOF.  Because
8870  * truncate_setsize() writes the inode size before removing pages, once we have
8871  * the page lock we can determine safely if the page is beyond EOF. If it is not
8872  * beyond EOF, then the page is guaranteed safe against truncation until we
8873  * unlock the page.
8874  */
8875 vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf)
8876 {
8877         struct page *page = vmf->page;
8878         struct inode *inode = file_inode(vmf->vma->vm_file);
8879         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8880         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8881         struct btrfs_ordered_extent *ordered;
8882         struct extent_state *cached_state = NULL;
8883         struct extent_changeset *data_reserved = NULL;
8884         char *kaddr;
8885         unsigned long zero_start;
8886         loff_t size;
8887         vm_fault_t ret;
8888         int ret2;
8889         int reserved = 0;
8890         u64 reserved_space;
8891         u64 page_start;
8892         u64 page_end;
8893         u64 end;
8894
8895         reserved_space = PAGE_SIZE;
8896
8897         sb_start_pagefault(inode->i_sb);
8898         page_start = page_offset(page);
8899         page_end = page_start + PAGE_SIZE - 1;
8900         end = page_end;
8901
8902         /*
8903          * Reserving delalloc space after obtaining the page lock can lead to
8904          * deadlock. For example, if a dirty page is locked by this function
8905          * and the call to btrfs_delalloc_reserve_space() ends up triggering
8906          * dirty page write out, then the btrfs_writepage() function could
8907          * end up waiting indefinitely to get a lock on the page currently
8908          * being processed by btrfs_page_mkwrite() function.
8909          */
8910         ret2 = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start,
8911                                            reserved_space);
8912         if (!ret2) {
8913                 ret2 = file_update_time(vmf->vma->vm_file);
8914                 reserved = 1;
8915         }
8916         if (ret2) {
8917                 ret = vmf_error(ret2);
8918                 if (reserved)
8919                         goto out;
8920                 goto out_noreserve;
8921         }
8922
8923         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8924 again:
8925         lock_page(page);
8926         size = i_size_read(inode);
8927
8928         if ((page->mapping != inode->i_mapping) ||
8929             (page_start >= size)) {
8930                 /* page got truncated out from underneath us */
8931                 goto out_unlock;
8932         }
8933         wait_on_page_writeback(page);
8934
8935         lock_extent_bits(io_tree, page_start, page_end, &cached_state);
8936         set_page_extent_mapped(page);
8937
8938         /*
8939          * we can't set the delalloc bits if there are pending ordered
8940          * extents.  Drop our locks and wait for them to finish
8941          */
8942         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), page_start,
8943                         PAGE_SIZE);
8944         if (ordered) {
8945                 unlock_extent_cached(io_tree, page_start, page_end,
8946                                      &cached_state);
8947                 unlock_page(page);
8948                 btrfs_start_ordered_extent(inode, ordered, 1);
8949                 btrfs_put_ordered_extent(ordered);
8950                 goto again;
8951         }
8952
8953         if (page->index == ((size - 1) >> PAGE_SHIFT)) {
8954                 reserved_space = round_up(size - page_start,
8955                                           fs_info->sectorsize);
8956                 if (reserved_space < PAGE_SIZE) {
8957                         end = page_start + reserved_space - 1;
8958                         btrfs_delalloc_release_space(inode, data_reserved,
8959                                         page_start, PAGE_SIZE - reserved_space,
8960                                         true);
8961                 }
8962         }
8963
8964         /*
8965          * page_mkwrite gets called when the page is firstly dirtied after it's
8966          * faulted in, but write(2) could also dirty a page and set delalloc
8967          * bits, thus in this case for space account reason, we still need to
8968          * clear any delalloc bits within this page range since we have to
8969          * reserve data&meta space before lock_page() (see above comments).
8970          */
8971         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
8972                           EXTENT_DIRTY | EXTENT_DELALLOC |
8973                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8974                           0, 0, &cached_state);
8975
8976         ret2 = btrfs_set_extent_delalloc(inode, page_start, end, 0,
8977                                         &cached_state, 0);
8978         if (ret2) {
8979                 unlock_extent_cached(io_tree, page_start, page_end,
8980                                      &cached_state);
8981                 ret = VM_FAULT_SIGBUS;
8982                 goto out_unlock;
8983         }
8984         ret2 = 0;
8985
8986         /* page is wholly or partially inside EOF */
8987         if (page_start + PAGE_SIZE > size)
8988                 zero_start = size & ~PAGE_MASK;
8989         else
8990                 zero_start = PAGE_SIZE;
8991
8992         if (zero_start != PAGE_SIZE) {
8993                 kaddr = kmap(page);
8994                 memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
8995                 flush_dcache_page(page);
8996                 kunmap(page);
8997         }
8998         ClearPageChecked(page);
8999         set_page_dirty(page);
9000         SetPageUptodate(page);
9001
9002         BTRFS_I(inode)->last_trans = fs_info->generation;
9003         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
9004         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
9005
9006         unlock_extent_cached(io_tree, page_start, page_end, &cached_state);
9007
9008         if (!ret2) {
9009                 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, true);
9010                 sb_end_pagefault(inode->i_sb);
9011                 extent_changeset_free(data_reserved);
9012                 return VM_FAULT_LOCKED;
9013         }
9014
9015 out_unlock:
9016         unlock_page(page);
9017 out:
9018         btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, (ret != 0));
9019         btrfs_delalloc_release_space(inode, data_reserved, page_start,
9020                                      reserved_space, (ret != 0));
9021 out_noreserve:
9022         sb_end_pagefault(inode->i_sb);
9023         extent_changeset_free(data_reserved);
9024         return ret;
9025 }
9026
9027 static int btrfs_truncate(struct inode *inode, bool skip_writeback)
9028 {
9029         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
9030         struct btrfs_root *root = BTRFS_I(inode)->root;
9031         struct btrfs_block_rsv *rsv;
9032         int ret;
9033         struct btrfs_trans_handle *trans;
9034         u64 mask = fs_info->sectorsize - 1;
9035         u64 min_size = btrfs_calc_trunc_metadata_size(fs_info, 1);
9036
9037         if (!skip_writeback) {
9038                 ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
9039                                                (u64)-1);
9040                 if (ret)
9041                         return ret;
9042         }
9043
9044         /*
9045          * Yes ladies and gentlemen, this is indeed ugly.  We have a couple of
9046          * things going on here:
9047          *
9048          * 1) We need to reserve space to update our inode.
9049          *
9050          * 2) We need to have something to cache all the space that is going to
9051          * be free'd up by the truncate operation, but also have some slack
9052          * space reserved in case it uses space during the truncate (thank you
9053          * very much snapshotting).
9054          *
9055          * And we need these to be separate.  The fact is we can use a lot of
9056          * space doing the truncate, and we have no earthly idea how much space
9057          * we will use, so we need the truncate reservation to be separate so it
9058          * doesn't end up using space reserved for updating the inode.  We also
9059          * need to be able to stop the transaction and start a new one, which
9060          * means we need to be able to update the inode several times, and we
9061          * have no idea of knowing how many times that will be, so we can't just
9062          * reserve 1 item for the entirety of the operation, so that has to be
9063          * done separately as well.
9064          *
9065          * So that leaves us with
9066          *
9067          * 1) rsv - for the truncate reservation, which we will steal from the
9068          * transaction reservation.
9069          * 2) fs_info->trans_block_rsv - this will have 1 items worth left for
9070          * updating the inode.
9071          */
9072         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
9073         if (!rsv)
9074                 return -ENOMEM;
9075         rsv->size = min_size;
9076         rsv->failfast = 1;
9077
9078         /*
9079          * 1 for the truncate slack space
9080          * 1 for updating the inode.
9081          */
9082         trans = btrfs_start_transaction(root, 2);
9083         if (IS_ERR(trans)) {
9084                 ret = PTR_ERR(trans);
9085                 goto out;
9086         }
9087
9088         /* Migrate the slack space for the truncate to our reserve */
9089         ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
9090                                       min_size, 0);
9091         BUG_ON(ret);
9092
9093         /*
9094          * So if we truncate and then write and fsync we normally would just
9095          * write the extents that changed, which is a problem if we need to
9096          * first truncate that entire inode.  So set this flag so we write out
9097          * all of the extents in the inode to the sync log so we're completely
9098          * safe.
9099          */
9100         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
9101         trans->block_rsv = rsv;
9102
9103         while (1) {
9104                 ret = btrfs_truncate_inode_items(trans, root, inode,
9105                                                  inode->i_size,
9106                                                  BTRFS_EXTENT_DATA_KEY);
9107                 trans->block_rsv = &fs_info->trans_block_rsv;
9108                 if (ret != -ENOSPC && ret != -EAGAIN)
9109                         break;
9110
9111                 ret = btrfs_update_inode(trans, root, inode);
9112                 if (ret)
9113                         break;
9114
9115                 btrfs_end_transaction(trans);
9116                 btrfs_btree_balance_dirty(fs_info);
9117
9118                 trans = btrfs_start_transaction(root, 2);
9119                 if (IS_ERR(trans)) {
9120                         ret = PTR_ERR(trans);
9121                         trans = NULL;
9122                         break;
9123                 }
9124
9125                 btrfs_block_rsv_release(fs_info, rsv, -1);
9126                 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
9127                                               rsv, min_size, 0);
9128                 BUG_ON(ret);    /* shouldn't happen */
9129                 trans->block_rsv = rsv;
9130         }
9131
9132         /*
9133          * We can't call btrfs_truncate_block inside a trans handle as we could
9134          * deadlock with freeze, if we got NEED_TRUNCATE_BLOCK then we know
9135          * we've truncated everything except the last little bit, and can do
9136          * btrfs_truncate_block and then update the disk_i_size.
9137          */
9138         if (ret == NEED_TRUNCATE_BLOCK) {
9139                 btrfs_end_transaction(trans);
9140                 btrfs_btree_balance_dirty(fs_info);
9141
9142                 ret = btrfs_truncate_block(inode, inode->i_size, 0, 0);
9143                 if (ret)
9144                         goto out;
9145                 trans = btrfs_start_transaction(root, 1);
9146                 if (IS_ERR(trans)) {
9147                         ret = PTR_ERR(trans);
9148                         goto out;
9149                 }
9150                 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
9151         }
9152
9153         if (trans) {
9154                 int ret2;
9155
9156                 trans->block_rsv = &fs_info->trans_block_rsv;
9157                 ret2 = btrfs_update_inode(trans, root, inode);
9158                 if (ret2 && !ret)
9159                         ret = ret2;
9160
9161                 ret2 = btrfs_end_transaction(trans);
9162                 if (ret2 && !ret)
9163                         ret = ret2;
9164                 btrfs_btree_balance_dirty(fs_info);
9165         }
9166 out:
9167         btrfs_free_block_rsv(fs_info, rsv);
9168
9169         return ret;
9170 }
9171
9172 /*
9173  * create a new subvolume directory/inode (helper for the ioctl).
9174  */
9175 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
9176                              struct btrfs_root *new_root,
9177                              struct btrfs_root *parent_root,
9178                              u64 new_dirid)
9179 {
9180         struct inode *inode;
9181         int err;
9182         u64 index = 0;
9183
9184         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
9185                                 new_dirid, new_dirid,
9186                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
9187                                 &index);
9188         if (IS_ERR(inode))
9189                 return PTR_ERR(inode);
9190         inode->i_op = &btrfs_dir_inode_operations;
9191         inode->i_fop = &btrfs_dir_file_operations;
9192
9193         set_nlink(inode, 1);
9194         btrfs_i_size_write(BTRFS_I(inode), 0);
9195         unlock_new_inode(inode);
9196
9197         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
9198         if (err)
9199                 btrfs_err(new_root->fs_info,
9200                           "error inheriting subvolume %llu properties: %d",
9201                           new_root->root_key.objectid, err);
9202
9203         err = btrfs_update_inode(trans, new_root, inode);
9204
9205         iput(inode);
9206         return err;
9207 }
9208
9209 struct inode *btrfs_alloc_inode(struct super_block *sb)
9210 {
9211         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
9212         struct btrfs_inode *ei;
9213         struct inode *inode;
9214
9215         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_KERNEL);
9216         if (!ei)
9217                 return NULL;
9218
9219         ei->root = NULL;
9220         ei->generation = 0;
9221         ei->last_trans = 0;
9222         ei->last_sub_trans = 0;
9223         ei->logged_trans = 0;
9224         ei->delalloc_bytes = 0;
9225         ei->new_delalloc_bytes = 0;
9226         ei->defrag_bytes = 0;
9227         ei->disk_i_size = 0;
9228         ei->flags = 0;
9229         ei->csum_bytes = 0;
9230         ei->index_cnt = (u64)-1;
9231         ei->dir_index = 0;
9232         ei->last_unlink_trans = 0;
9233         ei->last_log_commit = 0;
9234
9235         spin_lock_init(&ei->lock);
9236         ei->outstanding_extents = 0;
9237         if (sb->s_magic != BTRFS_TEST_MAGIC)
9238                 btrfs_init_metadata_block_rsv(fs_info, &ei->block_rsv,
9239                                               BTRFS_BLOCK_RSV_DELALLOC);
9240         ei->runtime_flags = 0;
9241         ei->prop_compress = BTRFS_COMPRESS_NONE;
9242         ei->defrag_compress = BTRFS_COMPRESS_NONE;
9243
9244         ei->delayed_node = NULL;
9245
9246         ei->i_otime.tv_sec = 0;
9247         ei->i_otime.tv_nsec = 0;
9248
9249         inode = &ei->vfs_inode;
9250         extent_map_tree_init(&ei->extent_tree);
9251         extent_io_tree_init(&ei->io_tree, inode);
9252         extent_io_tree_init(&ei->io_failure_tree, inode);
9253         ei->io_tree.track_uptodate = 1;
9254         ei->io_failure_tree.track_uptodate = 1;
9255         atomic_set(&ei->sync_writers, 0);
9256         mutex_init(&ei->log_mutex);
9257         mutex_init(&ei->delalloc_mutex);
9258         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
9259         INIT_LIST_HEAD(&ei->delalloc_inodes);
9260         INIT_LIST_HEAD(&ei->delayed_iput);
9261         RB_CLEAR_NODE(&ei->rb_node);
9262         init_rwsem(&ei->dio_sem);
9263
9264         return inode;
9265 }
9266
9267 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
9268 void btrfs_test_destroy_inode(struct inode *inode)
9269 {
9270         btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
9271         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9272 }
9273 #endif
9274
9275 static void btrfs_i_callback(struct rcu_head *head)
9276 {
9277         struct inode *inode = container_of(head, struct inode, i_rcu);
9278         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9279 }
9280
9281 void btrfs_destroy_inode(struct inode *inode)
9282 {
9283         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
9284         struct btrfs_ordered_extent *ordered;
9285         struct btrfs_root *root = BTRFS_I(inode)->root;
9286
9287         WARN_ON(!hlist_empty(&inode->i_dentry));
9288         WARN_ON(inode->i_data.nrpages);
9289         WARN_ON(BTRFS_I(inode)->block_rsv.reserved);
9290         WARN_ON(BTRFS_I(inode)->block_rsv.size);
9291         WARN_ON(BTRFS_I(inode)->outstanding_extents);
9292         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
9293         WARN_ON(BTRFS_I(inode)->new_delalloc_bytes);
9294         WARN_ON(BTRFS_I(inode)->csum_bytes);
9295         WARN_ON(BTRFS_I(inode)->defrag_bytes);
9296
9297         /*
9298          * This can happen where we create an inode, but somebody else also
9299          * created the same inode and we need to destroy the one we already
9300          * created.
9301          */
9302         if (!root)
9303                 goto free;
9304
9305         while (1) {
9306                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
9307                 if (!ordered)
9308                         break;
9309                 else {
9310                         btrfs_err(fs_info,
9311                                   "found ordered extent %llu %llu on inode cleanup",
9312                                   ordered->file_offset, ordered->len);
9313                         btrfs_remove_ordered_extent(inode, ordered);
9314                         btrfs_put_ordered_extent(ordered);
9315                         btrfs_put_ordered_extent(ordered);
9316                 }
9317         }
9318         btrfs_qgroup_check_reserved_leak(inode);
9319         inode_tree_del(inode);
9320         btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
9321 free:
9322         call_rcu(&inode->i_rcu, btrfs_i_callback);
9323 }
9324
9325 int btrfs_drop_inode(struct inode *inode)
9326 {
9327         struct btrfs_root *root = BTRFS_I(inode)->root;
9328
9329         if (root == NULL)
9330                 return 1;
9331
9332         /* the snap/subvol tree is on deleting */
9333         if (btrfs_root_refs(&root->root_item) == 0)
9334                 return 1;
9335         else
9336                 return generic_drop_inode(inode);
9337 }
9338
9339 static void init_once(void *foo)
9340 {
9341         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
9342
9343         inode_init_once(&ei->vfs_inode);
9344 }
9345
9346 void __cold btrfs_destroy_cachep(void)
9347 {
9348         /*
9349          * Make sure all delayed rcu free inodes are flushed before we
9350          * destroy cache.
9351          */
9352         rcu_barrier();
9353         kmem_cache_destroy(btrfs_inode_cachep);
9354         kmem_cache_destroy(btrfs_trans_handle_cachep);
9355         kmem_cache_destroy(btrfs_path_cachep);
9356         kmem_cache_destroy(btrfs_free_space_cachep);
9357 }
9358
9359 int __init btrfs_init_cachep(void)
9360 {
9361         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
9362                         sizeof(struct btrfs_inode), 0,
9363                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
9364                         init_once);
9365         if (!btrfs_inode_cachep)
9366                 goto fail;
9367
9368         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
9369                         sizeof(struct btrfs_trans_handle), 0,
9370                         SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
9371         if (!btrfs_trans_handle_cachep)
9372                 goto fail;
9373
9374         btrfs_path_cachep = kmem_cache_create("btrfs_path",
9375                         sizeof(struct btrfs_path), 0,
9376                         SLAB_MEM_SPREAD, NULL);
9377         if (!btrfs_path_cachep)
9378                 goto fail;
9379
9380         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
9381                         sizeof(struct btrfs_free_space), 0,
9382                         SLAB_MEM_SPREAD, NULL);
9383         if (!btrfs_free_space_cachep)
9384                 goto fail;
9385
9386         return 0;
9387 fail:
9388         btrfs_destroy_cachep();
9389         return -ENOMEM;
9390 }
9391
9392 static int btrfs_getattr(const struct path *path, struct kstat *stat,
9393                          u32 request_mask, unsigned int flags)
9394 {
9395         u64 delalloc_bytes;
9396         struct inode *inode = d_inode(path->dentry);
9397         u32 blocksize = inode->i_sb->s_blocksize;
9398         u32 bi_flags = BTRFS_I(inode)->flags;
9399
9400         stat->result_mask |= STATX_BTIME;
9401         stat->btime.tv_sec = BTRFS_I(inode)->i_otime.tv_sec;
9402         stat->btime.tv_nsec = BTRFS_I(inode)->i_otime.tv_nsec;
9403         if (bi_flags & BTRFS_INODE_APPEND)
9404                 stat->attributes |= STATX_ATTR_APPEND;
9405         if (bi_flags & BTRFS_INODE_COMPRESS)
9406                 stat->attributes |= STATX_ATTR_COMPRESSED;
9407         if (bi_flags & BTRFS_INODE_IMMUTABLE)
9408                 stat->attributes |= STATX_ATTR_IMMUTABLE;
9409         if (bi_flags & BTRFS_INODE_NODUMP)
9410                 stat->attributes |= STATX_ATTR_NODUMP;
9411
9412         stat->attributes_mask |= (STATX_ATTR_APPEND |
9413                                   STATX_ATTR_COMPRESSED |
9414                                   STATX_ATTR_IMMUTABLE |
9415                                   STATX_ATTR_NODUMP);
9416
9417         generic_fillattr(inode, stat);
9418         stat->dev = BTRFS_I(inode)->root->anon_dev;
9419
9420         spin_lock(&BTRFS_I(inode)->lock);
9421         delalloc_bytes = BTRFS_I(inode)->new_delalloc_bytes;
9422         spin_unlock(&BTRFS_I(inode)->lock);
9423         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
9424                         ALIGN(delalloc_bytes, blocksize)) >> 9;
9425         return 0;
9426 }
9427
9428 static int btrfs_rename_exchange(struct inode *old_dir,
9429                               struct dentry *old_dentry,
9430                               struct inode *new_dir,
9431                               struct dentry *new_dentry)
9432 {
9433         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9434         struct btrfs_trans_handle *trans;
9435         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9436         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9437         struct inode *new_inode = new_dentry->d_inode;
9438         struct inode *old_inode = old_dentry->d_inode;
9439         struct timespec64 ctime = current_time(old_inode);
9440         struct dentry *parent;
9441         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9442         u64 new_ino = btrfs_ino(BTRFS_I(new_inode));
9443         u64 old_idx = 0;
9444         u64 new_idx = 0;
9445         u64 root_objectid;
9446         int ret;
9447         int ret2;
9448         bool root_log_pinned = false;
9449         bool dest_log_pinned = false;
9450
9451         /* we only allow rename subvolume link between subvolumes */
9452         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9453                 return -EXDEV;
9454
9455         /* close the race window with snapshot create/destroy ioctl */
9456         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9457                 down_read(&fs_info->subvol_sem);
9458         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9459                 down_read(&fs_info->subvol_sem);
9460
9461         /*
9462          * We want to reserve the absolute worst case amount of items.  So if
9463          * both inodes are subvols and we need to unlink them then that would
9464          * require 4 item modifications, but if they are both normal inodes it
9465          * would require 5 item modifications, so we'll assume their normal
9466          * inodes.  So 5 * 2 is 10, plus 2 for the new links, so 12 total items
9467          * should cover the worst case number of items we'll modify.
9468          */
9469         trans = btrfs_start_transaction(root, 12);
9470         if (IS_ERR(trans)) {
9471                 ret = PTR_ERR(trans);
9472                 goto out_notrans;
9473         }
9474
9475         /*
9476          * We need to find a free sequence number both in the source and
9477          * in the destination directory for the exchange.
9478          */
9479         ret = btrfs_set_inode_index(BTRFS_I(new_dir), &old_idx);
9480         if (ret)
9481                 goto out_fail;
9482         ret = btrfs_set_inode_index(BTRFS_I(old_dir), &new_idx);
9483         if (ret)
9484                 goto out_fail;
9485
9486         BTRFS_I(old_inode)->dir_index = 0ULL;
9487         BTRFS_I(new_inode)->dir_index = 0ULL;
9488
9489         /* Reference for the source. */
9490         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9491                 /* force full log commit if subvolume involved. */
9492                 btrfs_set_log_full_commit(fs_info, trans);
9493         } else {
9494                 btrfs_pin_log_trans(root);
9495                 root_log_pinned = true;
9496                 ret = btrfs_insert_inode_ref(trans, dest,
9497                                              new_dentry->d_name.name,
9498                                              new_dentry->d_name.len,
9499                                              old_ino,
9500                                              btrfs_ino(BTRFS_I(new_dir)),
9501                                              old_idx);
9502                 if (ret)
9503                         goto out_fail;
9504         }
9505
9506         /* And now for the dest. */
9507         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9508                 /* force full log commit if subvolume involved. */
9509                 btrfs_set_log_full_commit(fs_info, trans);
9510         } else {
9511                 btrfs_pin_log_trans(dest);
9512                 dest_log_pinned = true;
9513                 ret = btrfs_insert_inode_ref(trans, root,
9514                                              old_dentry->d_name.name,
9515                                              old_dentry->d_name.len,
9516                                              new_ino,
9517                                              btrfs_ino(BTRFS_I(old_dir)),
9518                                              new_idx);
9519                 if (ret)
9520                         goto out_fail;
9521         }
9522
9523         /* Update inode version and ctime/mtime. */
9524         inode_inc_iversion(old_dir);
9525         inode_inc_iversion(new_dir);
9526         inode_inc_iversion(old_inode);
9527         inode_inc_iversion(new_inode);
9528         old_dir->i_ctime = old_dir->i_mtime = ctime;
9529         new_dir->i_ctime = new_dir->i_mtime = ctime;
9530         old_inode->i_ctime = ctime;
9531         new_inode->i_ctime = ctime;
9532
9533         if (old_dentry->d_parent != new_dentry->d_parent) {
9534                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9535                                 BTRFS_I(old_inode), 1);
9536                 btrfs_record_unlink_dir(trans, BTRFS_I(new_dir),
9537                                 BTRFS_I(new_inode), 1);
9538         }
9539
9540         /* src is a subvolume */
9541         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9542                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9543                 ret = btrfs_unlink_subvol(trans, root, old_dir,
9544                                           root_objectid,
9545                                           old_dentry->d_name.name,
9546                                           old_dentry->d_name.len);
9547         } else { /* src is an inode */
9548                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9549                                            BTRFS_I(old_dentry->d_inode),
9550                                            old_dentry->d_name.name,
9551                                            old_dentry->d_name.len);
9552                 if (!ret)
9553                         ret = btrfs_update_inode(trans, root, old_inode);
9554         }
9555         if (ret) {
9556                 btrfs_abort_transaction(trans, ret);
9557                 goto out_fail;
9558         }
9559
9560         /* dest is a subvolume */
9561         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9562                 root_objectid = BTRFS_I(new_inode)->root->root_key.objectid;
9563                 ret = btrfs_unlink_subvol(trans, dest, new_dir,
9564                                           root_objectid,
9565                                           new_dentry->d_name.name,
9566                                           new_dentry->d_name.len);
9567         } else { /* dest is an inode */
9568                 ret = __btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9569                                            BTRFS_I(new_dentry->d_inode),
9570                                            new_dentry->d_name.name,
9571                                            new_dentry->d_name.len);
9572                 if (!ret)
9573                         ret = btrfs_update_inode(trans, dest, new_inode);
9574         }
9575         if (ret) {
9576                 btrfs_abort_transaction(trans, ret);
9577                 goto out_fail;
9578         }
9579
9580         ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
9581                              new_dentry->d_name.name,
9582                              new_dentry->d_name.len, 0, old_idx);
9583         if (ret) {
9584                 btrfs_abort_transaction(trans, ret);
9585                 goto out_fail;
9586         }
9587
9588         ret = btrfs_add_link(trans, BTRFS_I(old_dir), BTRFS_I(new_inode),
9589                              old_dentry->d_name.name,
9590                              old_dentry->d_name.len, 0, new_idx);
9591         if (ret) {
9592                 btrfs_abort_transaction(trans, ret);
9593                 goto out_fail;
9594         }
9595
9596         if (old_inode->i_nlink == 1)
9597                 BTRFS_I(old_inode)->dir_index = old_idx;
9598         if (new_inode->i_nlink == 1)
9599                 BTRFS_I(new_inode)->dir_index = new_idx;
9600
9601         if (root_log_pinned) {
9602                 parent = new_dentry->d_parent;
9603                 btrfs_log_new_name(trans, BTRFS_I(old_inode), BTRFS_I(old_dir),
9604                                 parent);
9605                 btrfs_end_log_trans(root);
9606                 root_log_pinned = false;
9607         }
9608         if (dest_log_pinned) {
9609                 parent = old_dentry->d_parent;
9610                 btrfs_log_new_name(trans, BTRFS_I(new_inode), BTRFS_I(new_dir),
9611                                 parent);
9612                 btrfs_end_log_trans(dest);
9613                 dest_log_pinned = false;
9614         }
9615 out_fail:
9616         /*
9617          * If we have pinned a log and an error happened, we unpin tasks
9618          * trying to sync the log and force them to fallback to a transaction
9619          * commit if the log currently contains any of the inodes involved in
9620          * this rename operation (to ensure we do not persist a log with an
9621          * inconsistent state for any of these inodes or leading to any
9622          * inconsistencies when replayed). If the transaction was aborted, the
9623          * abortion reason is propagated to userspace when attempting to commit
9624          * the transaction. If the log does not contain any of these inodes, we
9625          * allow the tasks to sync it.
9626          */
9627         if (ret && (root_log_pinned || dest_log_pinned)) {
9628                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9629                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9630                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9631                     (new_inode &&
9632                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9633                         btrfs_set_log_full_commit(fs_info, trans);
9634
9635                 if (root_log_pinned) {
9636                         btrfs_end_log_trans(root);
9637                         root_log_pinned = false;
9638                 }
9639                 if (dest_log_pinned) {
9640                         btrfs_end_log_trans(dest);
9641                         dest_log_pinned = false;
9642                 }
9643         }
9644         ret2 = btrfs_end_transaction(trans);
9645         ret = ret ? ret : ret2;
9646 out_notrans:
9647         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9648                 up_read(&fs_info->subvol_sem);
9649         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9650                 up_read(&fs_info->subvol_sem);
9651
9652         return ret;
9653 }
9654
9655 static int btrfs_whiteout_for_rename(struct btrfs_trans_handle *trans,
9656                                      struct btrfs_root *root,
9657                                      struct inode *dir,
9658                                      struct dentry *dentry)
9659 {
9660         int ret;
9661         struct inode *inode;
9662         u64 objectid;
9663         u64 index;
9664
9665         ret = btrfs_find_free_ino(root, &objectid);
9666         if (ret)
9667                 return ret;
9668
9669         inode = btrfs_new_inode(trans, root, dir,
9670                                 dentry->d_name.name,
9671                                 dentry->d_name.len,
9672                                 btrfs_ino(BTRFS_I(dir)),
9673                                 objectid,
9674                                 S_IFCHR | WHITEOUT_MODE,
9675                                 &index);
9676
9677         if (IS_ERR(inode)) {
9678                 ret = PTR_ERR(inode);
9679                 return ret;
9680         }
9681
9682         inode->i_op = &btrfs_special_inode_operations;
9683         init_special_inode(inode, inode->i_mode,
9684                 WHITEOUT_DEV);
9685
9686         ret = btrfs_init_inode_security(trans, inode, dir,
9687                                 &dentry->d_name);
9688         if (ret)
9689                 goto out;
9690
9691         ret = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
9692                                 BTRFS_I(inode), 0, index);
9693         if (ret)
9694                 goto out;
9695
9696         ret = btrfs_update_inode(trans, root, inode);
9697 out:
9698         unlock_new_inode(inode);
9699         if (ret)
9700                 inode_dec_link_count(inode);
9701         iput(inode);
9702
9703         return ret;
9704 }
9705
9706 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9707                            struct inode *new_dir, struct dentry *new_dentry,
9708                            unsigned int flags)
9709 {
9710         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9711         struct btrfs_trans_handle *trans;
9712         unsigned int trans_num_items;
9713         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9714         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9715         struct inode *new_inode = d_inode(new_dentry);
9716         struct inode *old_inode = d_inode(old_dentry);
9717         u64 index = 0;
9718         u64 root_objectid;
9719         int ret;
9720         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9721         bool log_pinned = false;
9722
9723         if (btrfs_ino(BTRFS_I(new_dir)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9724                 return -EPERM;
9725
9726         /* we only allow rename subvolume link between subvolumes */
9727         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9728                 return -EXDEV;
9729
9730         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9731             (new_inode && btrfs_ino(BTRFS_I(new_inode)) == BTRFS_FIRST_FREE_OBJECTID))
9732                 return -ENOTEMPTY;
9733
9734         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9735             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9736                 return -ENOTEMPTY;
9737
9738
9739         /* check for collisions, even if the  name isn't there */
9740         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9741                              new_dentry->d_name.name,
9742                              new_dentry->d_name.len);
9743
9744         if (ret) {
9745                 if (ret == -EEXIST) {
9746                         /* we shouldn't get
9747                          * eexist without a new_inode */
9748                         if (WARN_ON(!new_inode)) {
9749                                 return ret;
9750                         }
9751                 } else {
9752                         /* maybe -EOVERFLOW */
9753                         return ret;
9754                 }
9755         }
9756         ret = 0;
9757
9758         /*
9759          * we're using rename to replace one file with another.  Start IO on it
9760          * now so  we don't add too much work to the end of the transaction
9761          */
9762         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9763                 filemap_flush(old_inode->i_mapping);
9764
9765         /* close the racy window with snapshot create/destroy ioctl */
9766         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9767                 down_read(&fs_info->subvol_sem);
9768         /*
9769          * We want to reserve the absolute worst case amount of items.  So if
9770          * both inodes are subvols and we need to unlink them then that would
9771          * require 4 item modifications, but if they are both normal inodes it
9772          * would require 5 item modifications, so we'll assume they are normal
9773          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9774          * should cover the worst case number of items we'll modify.
9775          * If our rename has the whiteout flag, we need more 5 units for the
9776          * new inode (1 inode item, 1 inode ref, 2 dir items and 1 xattr item
9777          * when selinux is enabled).
9778          */
9779         trans_num_items = 11;
9780         if (flags & RENAME_WHITEOUT)
9781                 trans_num_items += 5;
9782         trans = btrfs_start_transaction(root, trans_num_items);
9783         if (IS_ERR(trans)) {
9784                 ret = PTR_ERR(trans);
9785                 goto out_notrans;
9786         }
9787
9788         if (dest != root)
9789                 btrfs_record_root_in_trans(trans, dest);
9790
9791         ret = btrfs_set_inode_index(BTRFS_I(new_dir), &index);
9792         if (ret)
9793                 goto out_fail;
9794
9795         BTRFS_I(old_inode)->dir_index = 0ULL;
9796         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9797                 /* force full log commit if subvolume involved. */
9798                 btrfs_set_log_full_commit(fs_info, trans);
9799         } else {
9800                 btrfs_pin_log_trans(root);
9801                 log_pinned = true;
9802                 ret = btrfs_insert_inode_ref(trans, dest,
9803                                              new_dentry->d_name.name,
9804                                              new_dentry->d_name.len,
9805                                              old_ino,
9806                                              btrfs_ino(BTRFS_I(new_dir)), index);
9807                 if (ret)
9808                         goto out_fail;
9809         }
9810
9811         inode_inc_iversion(old_dir);
9812         inode_inc_iversion(new_dir);
9813         inode_inc_iversion(old_inode);
9814         old_dir->i_ctime = old_dir->i_mtime =
9815         new_dir->i_ctime = new_dir->i_mtime =
9816         old_inode->i_ctime = current_time(old_dir);
9817
9818         if (old_dentry->d_parent != new_dentry->d_parent)
9819                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9820                                 BTRFS_I(old_inode), 1);
9821
9822         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9823                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9824                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
9825                                         old_dentry->d_name.name,
9826                                         old_dentry->d_name.len);
9827         } else {
9828                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9829                                         BTRFS_I(d_inode(old_dentry)),
9830                                         old_dentry->d_name.name,
9831                                         old_dentry->d_name.len);
9832                 if (!ret)
9833                         ret = btrfs_update_inode(trans, root, old_inode);
9834         }
9835         if (ret) {
9836                 btrfs_abort_transaction(trans, ret);
9837                 goto out_fail;
9838         }
9839
9840         if (new_inode) {
9841                 inode_inc_iversion(new_inode);
9842                 new_inode->i_ctime = current_time(new_inode);
9843                 if (unlikely(btrfs_ino(BTRFS_I(new_inode)) ==
9844                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9845                         root_objectid = BTRFS_I(new_inode)->location.objectid;
9846                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
9847                                                 root_objectid,
9848                                                 new_dentry->d_name.name,
9849                                                 new_dentry->d_name.len);
9850                         BUG_ON(new_inode->i_nlink == 0);
9851                 } else {
9852                         ret = btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9853                                                  BTRFS_I(d_inode(new_dentry)),
9854                                                  new_dentry->d_name.name,
9855                                                  new_dentry->d_name.len);
9856                 }
9857                 if (!ret && new_inode->i_nlink == 0)
9858                         ret = btrfs_orphan_add(trans,
9859                                         BTRFS_I(d_inode(new_dentry)));
9860                 if (ret) {
9861                         btrfs_abort_transaction(trans, ret);
9862                         goto out_fail;
9863                 }
9864         }
9865
9866         ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
9867                              new_dentry->d_name.name,
9868                              new_dentry->d_name.len, 0, index);
9869         if (ret) {
9870                 btrfs_abort_transaction(trans, ret);
9871                 goto out_fail;
9872         }
9873
9874         if (old_inode->i_nlink == 1)
9875                 BTRFS_I(old_inode)->dir_index = index;
9876
9877         if (log_pinned) {
9878                 struct dentry *parent = new_dentry->d_parent;
9879
9880                 btrfs_log_new_name(trans, BTRFS_I(old_inode), BTRFS_I(old_dir),
9881                                 parent);
9882                 btrfs_end_log_trans(root);
9883                 log_pinned = false;
9884         }
9885
9886         if (flags & RENAME_WHITEOUT) {
9887                 ret = btrfs_whiteout_for_rename(trans, root, old_dir,
9888                                                 old_dentry);
9889
9890                 if (ret) {
9891                         btrfs_abort_transaction(trans, ret);
9892                         goto out_fail;
9893                 }
9894         }
9895 out_fail:
9896         /*
9897          * If we have pinned the log and an error happened, we unpin tasks
9898          * trying to sync the log and force them to fallback to a transaction
9899          * commit if the log currently contains any of the inodes involved in
9900          * this rename operation (to ensure we do not persist a log with an
9901          * inconsistent state for any of these inodes or leading to any
9902          * inconsistencies when replayed). If the transaction was aborted, the
9903          * abortion reason is propagated to userspace when attempting to commit
9904          * the transaction. If the log does not contain any of these inodes, we
9905          * allow the tasks to sync it.
9906          */
9907         if (ret && log_pinned) {
9908                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9909                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9910                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9911                     (new_inode &&
9912                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9913                         btrfs_set_log_full_commit(fs_info, trans);
9914
9915                 btrfs_end_log_trans(root);
9916                 log_pinned = false;
9917         }
9918         btrfs_end_transaction(trans);
9919 out_notrans:
9920         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9921                 up_read(&fs_info->subvol_sem);
9922
9923         return ret;
9924 }
9925
9926 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9927                          struct inode *new_dir, struct dentry *new_dentry,
9928                          unsigned int flags)
9929 {
9930         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
9931                 return -EINVAL;
9932
9933         if (flags & RENAME_EXCHANGE)
9934                 return btrfs_rename_exchange(old_dir, old_dentry, new_dir,
9935                                           new_dentry);
9936
9937         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
9938 }
9939
9940 struct btrfs_delalloc_work {
9941         struct inode *inode;
9942         struct completion completion;
9943         struct list_head list;
9944         struct btrfs_work work;
9945 };
9946
9947 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9948 {
9949         struct btrfs_delalloc_work *delalloc_work;
9950         struct inode *inode;
9951
9952         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9953                                      work);
9954         inode = delalloc_work->inode;
9955         filemap_flush(inode->i_mapping);
9956         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
9957                                 &BTRFS_I(inode)->runtime_flags))
9958                 filemap_flush(inode->i_mapping);
9959
9960         iput(inode);
9961         complete(&delalloc_work->completion);
9962 }
9963
9964 static struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode)
9965 {
9966         struct btrfs_delalloc_work *work;
9967
9968         work = kmalloc(sizeof(*work), GFP_NOFS);
9969         if (!work)
9970                 return NULL;
9971
9972         init_completion(&work->completion);
9973         INIT_LIST_HEAD(&work->list);
9974         work->inode = inode;
9975         WARN_ON_ONCE(!inode);
9976         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
9977                         btrfs_run_delalloc_work, NULL, NULL);
9978
9979         return work;
9980 }
9981
9982 /*
9983  * some fairly slow code that needs optimization. This walks the list
9984  * of all the inodes with pending delalloc and forces them to disk.
9985  */
9986 static int start_delalloc_inodes(struct btrfs_root *root, int nr)
9987 {
9988         struct btrfs_inode *binode;
9989         struct inode *inode;
9990         struct btrfs_delalloc_work *work, *next;
9991         struct list_head works;
9992         struct list_head splice;
9993         int ret = 0;
9994
9995         INIT_LIST_HEAD(&works);
9996         INIT_LIST_HEAD(&splice);
9997
9998         mutex_lock(&root->delalloc_mutex);
9999         spin_lock(&root->delalloc_lock);
10000         list_splice_init(&root->delalloc_inodes, &splice);
10001         while (!list_empty(&splice)) {
10002                 binode = list_entry(splice.next, struct btrfs_inode,
10003                                     delalloc_inodes);
10004
10005                 list_move_tail(&binode->delalloc_inodes,
10006                                &root->delalloc_inodes);
10007                 inode = igrab(&binode->vfs_inode);
10008                 if (!inode) {
10009                         cond_resched_lock(&root->delalloc_lock);
10010                         continue;
10011                 }
10012                 spin_unlock(&root->delalloc_lock);
10013
10014                 work = btrfs_alloc_delalloc_work(inode);
10015                 if (!work) {
10016                         iput(inode);
10017                         ret = -ENOMEM;
10018                         goto out;
10019                 }
10020                 list_add_tail(&work->list, &works);
10021                 btrfs_queue_work(root->fs_info->flush_workers,
10022                                  &work->work);
10023                 ret++;
10024                 if (nr != -1 && ret >= nr)
10025                         goto out;
10026                 cond_resched();
10027                 spin_lock(&root->delalloc_lock);
10028         }
10029         spin_unlock(&root->delalloc_lock);
10030
10031 out:
10032         list_for_each_entry_safe(work, next, &works, list) {
10033                 list_del_init(&work->list);
10034                 wait_for_completion(&work->completion);
10035                 kfree(work);
10036         }
10037
10038         if (!list_empty(&splice)) {
10039                 spin_lock(&root->delalloc_lock);
10040                 list_splice_tail(&splice, &root->delalloc_inodes);
10041                 spin_unlock(&root->delalloc_lock);
10042         }
10043         mutex_unlock(&root->delalloc_mutex);
10044         return ret;
10045 }
10046
10047 int btrfs_start_delalloc_inodes(struct btrfs_root *root)
10048 {
10049         struct btrfs_fs_info *fs_info = root->fs_info;
10050         int ret;
10051
10052         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10053                 return -EROFS;
10054
10055         ret = start_delalloc_inodes(root, -1);
10056         if (ret > 0)
10057                 ret = 0;
10058         return ret;
10059 }
10060
10061 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int nr)
10062 {
10063         struct btrfs_root *root;
10064         struct list_head splice;
10065         int ret;
10066
10067         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10068                 return -EROFS;
10069
10070         INIT_LIST_HEAD(&splice);
10071
10072         mutex_lock(&fs_info->delalloc_root_mutex);
10073         spin_lock(&fs_info->delalloc_root_lock);
10074         list_splice_init(&fs_info->delalloc_roots, &splice);
10075         while (!list_empty(&splice) && nr) {
10076                 root = list_first_entry(&splice, struct btrfs_root,
10077                                         delalloc_root);
10078                 root = btrfs_grab_fs_root(root);
10079                 BUG_ON(!root);
10080                 list_move_tail(&root->delalloc_root,
10081                                &fs_info->delalloc_roots);
10082                 spin_unlock(&fs_info->delalloc_root_lock);
10083
10084                 ret = start_delalloc_inodes(root, nr);
10085                 btrfs_put_fs_root(root);
10086                 if (ret < 0)
10087                         goto out;
10088
10089                 if (nr != -1) {
10090                         nr -= ret;
10091                         WARN_ON(nr < 0);
10092                 }
10093                 spin_lock(&fs_info->delalloc_root_lock);
10094         }
10095         spin_unlock(&fs_info->delalloc_root_lock);
10096
10097         ret = 0;
10098 out:
10099         if (!list_empty(&splice)) {
10100                 spin_lock(&fs_info->delalloc_root_lock);
10101                 list_splice_tail(&splice, &fs_info->delalloc_roots);
10102                 spin_unlock(&fs_info->delalloc_root_lock);
10103         }
10104         mutex_unlock(&fs_info->delalloc_root_mutex);
10105         return ret;
10106 }
10107
10108 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
10109                          const char *symname)
10110 {
10111         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10112         struct btrfs_trans_handle *trans;
10113         struct btrfs_root *root = BTRFS_I(dir)->root;
10114         struct btrfs_path *path;
10115         struct btrfs_key key;
10116         struct inode *inode = NULL;
10117         int err;
10118         int drop_inode = 0;
10119         u64 objectid;
10120         u64 index = 0;
10121         int name_len;
10122         int datasize;
10123         unsigned long ptr;
10124         struct btrfs_file_extent_item *ei;
10125         struct extent_buffer *leaf;
10126
10127         name_len = strlen(symname);
10128         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info))
10129                 return -ENAMETOOLONG;
10130
10131         /*
10132          * 2 items for inode item and ref
10133          * 2 items for dir items
10134          * 1 item for updating parent inode item
10135          * 1 item for the inline extent item
10136          * 1 item for xattr if selinux is on
10137          */
10138         trans = btrfs_start_transaction(root, 7);
10139         if (IS_ERR(trans))
10140                 return PTR_ERR(trans);
10141
10142         err = btrfs_find_free_ino(root, &objectid);
10143         if (err)
10144                 goto out_unlock;
10145
10146         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
10147                                 dentry->d_name.len, btrfs_ino(BTRFS_I(dir)),
10148                                 objectid, S_IFLNK|S_IRWXUGO, &index);
10149         if (IS_ERR(inode)) {
10150                 err = PTR_ERR(inode);
10151                 goto out_unlock;
10152         }
10153
10154         /*
10155         * If the active LSM wants to access the inode during
10156         * d_instantiate it needs these. Smack checks to see
10157         * if the filesystem supports xattrs by looking at the
10158         * ops vector.
10159         */
10160         inode->i_fop = &btrfs_file_operations;
10161         inode->i_op = &btrfs_file_inode_operations;
10162         inode->i_mapping->a_ops = &btrfs_aops;
10163         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10164
10165         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
10166         if (err)
10167                 goto out_unlock_inode;
10168
10169         path = btrfs_alloc_path();
10170         if (!path) {
10171                 err = -ENOMEM;
10172                 goto out_unlock_inode;
10173         }
10174         key.objectid = btrfs_ino(BTRFS_I(inode));
10175         key.offset = 0;
10176         key.type = BTRFS_EXTENT_DATA_KEY;
10177         datasize = btrfs_file_extent_calc_inline_size(name_len);
10178         err = btrfs_insert_empty_item(trans, root, path, &key,
10179                                       datasize);
10180         if (err) {
10181                 btrfs_free_path(path);
10182                 goto out_unlock_inode;
10183         }
10184         leaf = path->nodes[0];
10185         ei = btrfs_item_ptr(leaf, path->slots[0],
10186                             struct btrfs_file_extent_item);
10187         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
10188         btrfs_set_file_extent_type(leaf, ei,
10189                                    BTRFS_FILE_EXTENT_INLINE);
10190         btrfs_set_file_extent_encryption(leaf, ei, 0);
10191         btrfs_set_file_extent_compression(leaf, ei, 0);
10192         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
10193         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
10194
10195         ptr = btrfs_file_extent_inline_start(ei);
10196         write_extent_buffer(leaf, symname, ptr, name_len);
10197         btrfs_mark_buffer_dirty(leaf);
10198         btrfs_free_path(path);
10199
10200         inode->i_op = &btrfs_symlink_inode_operations;
10201         inode_nohighmem(inode);
10202         inode->i_mapping->a_ops = &btrfs_symlink_aops;
10203         inode_set_bytes(inode, name_len);
10204         btrfs_i_size_write(BTRFS_I(inode), name_len);
10205         err = btrfs_update_inode(trans, root, inode);
10206         /*
10207          * Last step, add directory indexes for our symlink inode. This is the
10208          * last step to avoid extra cleanup of these indexes if an error happens
10209          * elsewhere above.
10210          */
10211         if (!err)
10212                 err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
10213                                 BTRFS_I(inode), 0, index);
10214         if (err) {
10215                 drop_inode = 1;
10216                 goto out_unlock_inode;
10217         }
10218
10219         d_instantiate_new(dentry, inode);
10220
10221 out_unlock:
10222         btrfs_end_transaction(trans);
10223         if (drop_inode) {
10224                 inode_dec_link_count(inode);
10225                 iput(inode);
10226         }
10227         btrfs_btree_balance_dirty(fs_info);
10228         return err;
10229
10230 out_unlock_inode:
10231         drop_inode = 1;
10232         unlock_new_inode(inode);
10233         goto out_unlock;
10234 }
10235
10236 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
10237                                        u64 start, u64 num_bytes, u64 min_size,
10238                                        loff_t actual_len, u64 *alloc_hint,
10239                                        struct btrfs_trans_handle *trans)
10240 {
10241         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
10242         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
10243         struct extent_map *em;
10244         struct btrfs_root *root = BTRFS_I(inode)->root;
10245         struct btrfs_key ins;
10246         u64 cur_offset = start;
10247         u64 i_size;
10248         u64 cur_bytes;
10249         u64 last_alloc = (u64)-1;
10250         int ret = 0;
10251         bool own_trans = true;
10252         u64 end = start + num_bytes - 1;
10253
10254         if (trans)
10255                 own_trans = false;
10256         while (num_bytes > 0) {
10257                 if (own_trans) {
10258                         trans = btrfs_start_transaction(root, 3);
10259                         if (IS_ERR(trans)) {
10260                                 ret = PTR_ERR(trans);
10261                                 break;
10262                         }
10263                 }
10264
10265                 cur_bytes = min_t(u64, num_bytes, SZ_256M);
10266                 cur_bytes = max(cur_bytes, min_size);
10267                 /*
10268                  * If we are severely fragmented we could end up with really
10269                  * small allocations, so if the allocator is returning small
10270                  * chunks lets make its job easier by only searching for those
10271                  * sized chunks.
10272                  */
10273                 cur_bytes = min(cur_bytes, last_alloc);
10274                 ret = btrfs_reserve_extent(root, cur_bytes, cur_bytes,
10275                                 min_size, 0, *alloc_hint, &ins, 1, 0);
10276                 if (ret) {
10277                         if (own_trans)
10278                                 btrfs_end_transaction(trans);
10279                         break;
10280                 }
10281                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
10282
10283                 last_alloc = ins.offset;
10284                 ret = insert_reserved_file_extent(trans, inode,
10285                                                   cur_offset, ins.objectid,
10286                                                   ins.offset, ins.offset,
10287                                                   ins.offset, 0, 0, 0,
10288                                                   BTRFS_FILE_EXTENT_PREALLOC);
10289                 if (ret) {
10290                         btrfs_free_reserved_extent(fs_info, ins.objectid,
10291                                                    ins.offset, 0);
10292                         btrfs_abort_transaction(trans, ret);
10293                         if (own_trans)
10294                                 btrfs_end_transaction(trans);
10295                         break;
10296                 }
10297
10298                 btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
10299                                         cur_offset + ins.offset -1, 0);
10300
10301                 em = alloc_extent_map();
10302                 if (!em) {
10303                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
10304                                 &BTRFS_I(inode)->runtime_flags);
10305                         goto next;
10306                 }
10307
10308                 em->start = cur_offset;
10309                 em->orig_start = cur_offset;
10310                 em->len = ins.offset;
10311                 em->block_start = ins.objectid;
10312                 em->block_len = ins.offset;
10313                 em->orig_block_len = ins.offset;
10314                 em->ram_bytes = ins.offset;
10315                 em->bdev = fs_info->fs_devices->latest_bdev;
10316                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
10317                 em->generation = trans->transid;
10318
10319                 while (1) {
10320                         write_lock(&em_tree->lock);
10321                         ret = add_extent_mapping(em_tree, em, 1);
10322                         write_unlock(&em_tree->lock);
10323                         if (ret != -EEXIST)
10324                                 break;
10325                         btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
10326                                                 cur_offset + ins.offset - 1,
10327                                                 0);
10328                 }
10329                 free_extent_map(em);
10330 next:
10331                 num_bytes -= ins.offset;
10332                 cur_offset += ins.offset;
10333                 *alloc_hint = ins.objectid + ins.offset;
10334
10335                 inode_inc_iversion(inode);
10336                 inode->i_ctime = current_time(inode);
10337                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
10338                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
10339                     (actual_len > inode->i_size) &&
10340                     (cur_offset > inode->i_size)) {
10341                         if (cur_offset > actual_len)
10342                                 i_size = actual_len;
10343                         else
10344                                 i_size = cur_offset;
10345                         i_size_write(inode, i_size);
10346                         btrfs_ordered_update_i_size(inode, i_size, NULL);
10347                 }
10348
10349                 ret = btrfs_update_inode(trans, root, inode);
10350
10351                 if (ret) {
10352                         btrfs_abort_transaction(trans, ret);
10353                         if (own_trans)
10354                                 btrfs_end_transaction(trans);
10355                         break;
10356                 }
10357
10358                 if (own_trans)
10359                         btrfs_end_transaction(trans);
10360         }
10361         if (cur_offset < end)
10362                 btrfs_free_reserved_data_space(inode, NULL, cur_offset,
10363                         end - cur_offset + 1);
10364         return ret;
10365 }
10366
10367 int btrfs_prealloc_file_range(struct inode *inode, int mode,
10368                               u64 start, u64 num_bytes, u64 min_size,
10369                               loff_t actual_len, u64 *alloc_hint)
10370 {
10371         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10372                                            min_size, actual_len, alloc_hint,
10373                                            NULL);
10374 }
10375
10376 int btrfs_prealloc_file_range_trans(struct inode *inode,
10377                                     struct btrfs_trans_handle *trans, int mode,
10378                                     u64 start, u64 num_bytes, u64 min_size,
10379                                     loff_t actual_len, u64 *alloc_hint)
10380 {
10381         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10382                                            min_size, actual_len, alloc_hint, trans);
10383 }
10384
10385 static int btrfs_set_page_dirty(struct page *page)
10386 {
10387         return __set_page_dirty_nobuffers(page);
10388 }
10389
10390 static int btrfs_permission(struct inode *inode, int mask)
10391 {
10392         struct btrfs_root *root = BTRFS_I(inode)->root;
10393         umode_t mode = inode->i_mode;
10394
10395         if (mask & MAY_WRITE &&
10396             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
10397                 if (btrfs_root_readonly(root))
10398                         return -EROFS;
10399                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
10400                         return -EACCES;
10401         }
10402         return generic_permission(inode, mask);
10403 }
10404
10405 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
10406 {
10407         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10408         struct btrfs_trans_handle *trans;
10409         struct btrfs_root *root = BTRFS_I(dir)->root;
10410         struct inode *inode = NULL;
10411         u64 objectid;
10412         u64 index;
10413         int ret = 0;
10414
10415         /*
10416          * 5 units required for adding orphan entry
10417          */
10418         trans = btrfs_start_transaction(root, 5);
10419         if (IS_ERR(trans))
10420                 return PTR_ERR(trans);
10421
10422         ret = btrfs_find_free_ino(root, &objectid);
10423         if (ret)
10424                 goto out;
10425
10426         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
10427                         btrfs_ino(BTRFS_I(dir)), objectid, mode, &index);
10428         if (IS_ERR(inode)) {
10429                 ret = PTR_ERR(inode);
10430                 inode = NULL;
10431                 goto out;
10432         }
10433
10434         inode->i_fop = &btrfs_file_operations;
10435         inode->i_op = &btrfs_file_inode_operations;
10436
10437         inode->i_mapping->a_ops = &btrfs_aops;
10438         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10439
10440         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
10441         if (ret)
10442                 goto out_inode;
10443
10444         ret = btrfs_update_inode(trans, root, inode);
10445         if (ret)
10446                 goto out_inode;
10447         ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10448         if (ret)
10449                 goto out_inode;
10450
10451         /*
10452          * We set number of links to 0 in btrfs_new_inode(), and here we set
10453          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
10454          * through:
10455          *
10456          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
10457          */
10458         set_nlink(inode, 1);
10459         unlock_new_inode(inode);
10460         d_tmpfile(dentry, inode);
10461         mark_inode_dirty(inode);
10462
10463 out:
10464         btrfs_end_transaction(trans);
10465         if (ret)
10466                 iput(inode);
10467         btrfs_btree_balance_dirty(fs_info);
10468         return ret;
10469
10470 out_inode:
10471         unlock_new_inode(inode);
10472         goto out;
10473
10474 }
10475
10476 __attribute__((const))
10477 static int btrfs_readpage_io_failed_hook(struct page *page, int failed_mirror)
10478 {
10479         return -EAGAIN;
10480 }
10481
10482 static struct btrfs_fs_info *iotree_fs_info(void *private_data)
10483 {
10484         struct inode *inode = private_data;
10485         return btrfs_sb(inode->i_sb);
10486 }
10487
10488 static void btrfs_check_extent_io_range(void *private_data, const char *caller,
10489                                         u64 start, u64 end)
10490 {
10491         struct inode *inode = private_data;
10492         u64 isize;
10493
10494         isize = i_size_read(inode);
10495         if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
10496                 btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
10497                     "%s: ino %llu isize %llu odd range [%llu,%llu]",
10498                         caller, btrfs_ino(BTRFS_I(inode)), isize, start, end);
10499         }
10500 }
10501
10502 void btrfs_set_range_writeback(void *private_data, u64 start, u64 end)
10503 {
10504         struct inode *inode = private_data;
10505         unsigned long index = start >> PAGE_SHIFT;
10506         unsigned long end_index = end >> PAGE_SHIFT;
10507         struct page *page;
10508
10509         while (index <= end_index) {
10510                 page = find_get_page(inode->i_mapping, index);
10511                 ASSERT(page); /* Pages should be in the extent_io_tree */
10512                 set_page_writeback(page);
10513                 put_page(page);
10514                 index++;
10515         }
10516 }
10517
10518 static const struct inode_operations btrfs_dir_inode_operations = {
10519         .getattr        = btrfs_getattr,
10520         .lookup         = btrfs_lookup,
10521         .create         = btrfs_create,
10522         .unlink         = btrfs_unlink,
10523         .link           = btrfs_link,
10524         .mkdir          = btrfs_mkdir,
10525         .rmdir          = btrfs_rmdir,
10526         .rename         = btrfs_rename2,
10527         .symlink        = btrfs_symlink,
10528         .setattr        = btrfs_setattr,
10529         .mknod          = btrfs_mknod,
10530         .listxattr      = btrfs_listxattr,
10531         .permission     = btrfs_permission,
10532         .get_acl        = btrfs_get_acl,
10533         .set_acl        = btrfs_set_acl,
10534         .update_time    = btrfs_update_time,
10535         .tmpfile        = btrfs_tmpfile,
10536 };
10537 static const struct inode_operations btrfs_dir_ro_inode_operations = {
10538         .lookup         = btrfs_lookup,
10539         .permission     = btrfs_permission,
10540         .update_time    = btrfs_update_time,
10541 };
10542
10543 static const struct file_operations btrfs_dir_file_operations = {
10544         .llseek         = generic_file_llseek,
10545         .read           = generic_read_dir,
10546         .iterate_shared = btrfs_real_readdir,
10547         .open           = btrfs_opendir,
10548         .unlocked_ioctl = btrfs_ioctl,
10549 #ifdef CONFIG_COMPAT
10550         .compat_ioctl   = btrfs_compat_ioctl,
10551 #endif
10552         .release        = btrfs_release_file,
10553         .fsync          = btrfs_sync_file,
10554 };
10555
10556 static const struct extent_io_ops btrfs_extent_io_ops = {
10557         /* mandatory callbacks */
10558         .submit_bio_hook = btrfs_submit_bio_hook,
10559         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10560         .merge_bio_hook = btrfs_merge_bio_hook,
10561         .readpage_io_failed_hook = btrfs_readpage_io_failed_hook,
10562         .tree_fs_info = iotree_fs_info,
10563         .set_range_writeback = btrfs_set_range_writeback,
10564
10565         /* optional callbacks */
10566         .fill_delalloc = run_delalloc_range,
10567         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
10568         .writepage_start_hook = btrfs_writepage_start_hook,
10569         .set_bit_hook = btrfs_set_bit_hook,
10570         .clear_bit_hook = btrfs_clear_bit_hook,
10571         .merge_extent_hook = btrfs_merge_extent_hook,
10572         .split_extent_hook = btrfs_split_extent_hook,
10573         .check_extent_io_range = btrfs_check_extent_io_range,
10574 };
10575
10576 /*
10577  * btrfs doesn't support the bmap operation because swapfiles
10578  * use bmap to make a mapping of extents in the file.  They assume
10579  * these extents won't change over the life of the file and they
10580  * use the bmap result to do IO directly to the drive.
10581  *
10582  * the btrfs bmap call would return logical addresses that aren't
10583  * suitable for IO and they also will change frequently as COW
10584  * operations happen.  So, swapfile + btrfs == corruption.
10585  *
10586  * For now we're avoiding this by dropping bmap.
10587  */
10588 static const struct address_space_operations btrfs_aops = {
10589         .readpage       = btrfs_readpage,
10590         .writepage      = btrfs_writepage,
10591         .writepages     = btrfs_writepages,
10592         .readpages      = btrfs_readpages,
10593         .direct_IO      = btrfs_direct_IO,
10594         .invalidatepage = btrfs_invalidatepage,
10595         .releasepage    = btrfs_releasepage,
10596         .set_page_dirty = btrfs_set_page_dirty,
10597         .error_remove_page = generic_error_remove_page,
10598 };
10599
10600 static const struct address_space_operations btrfs_symlink_aops = {
10601         .readpage       = btrfs_readpage,
10602         .writepage      = btrfs_writepage,
10603         .invalidatepage = btrfs_invalidatepage,
10604         .releasepage    = btrfs_releasepage,
10605 };
10606
10607 static const struct inode_operations btrfs_file_inode_operations = {
10608         .getattr        = btrfs_getattr,
10609         .setattr        = btrfs_setattr,
10610         .listxattr      = btrfs_listxattr,
10611         .permission     = btrfs_permission,
10612         .fiemap         = btrfs_fiemap,
10613         .get_acl        = btrfs_get_acl,
10614         .set_acl        = btrfs_set_acl,
10615         .update_time    = btrfs_update_time,
10616 };
10617 static const struct inode_operations btrfs_special_inode_operations = {
10618         .getattr        = btrfs_getattr,
10619         .setattr        = btrfs_setattr,
10620         .permission     = btrfs_permission,
10621         .listxattr      = btrfs_listxattr,
10622         .get_acl        = btrfs_get_acl,
10623         .set_acl        = btrfs_set_acl,
10624         .update_time    = btrfs_update_time,
10625 };
10626 static const struct inode_operations btrfs_symlink_inode_operations = {
10627         .get_link       = page_get_link,
10628         .getattr        = btrfs_getattr,
10629         .setattr        = btrfs_setattr,
10630         .permission     = btrfs_permission,
10631         .listxattr      = btrfs_listxattr,
10632         .update_time    = btrfs_update_time,
10633 };
10634
10635 const struct dentry_operations btrfs_dentry_operations = {
10636         .d_delete       = btrfs_dentry_delete,
10637 };