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