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