diff options
Diffstat (limited to 'fs/btrfs/file.c')
| -rw-r--r-- | fs/btrfs/file.c | 112 |
1 files changed, 98 insertions, 14 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index e46bfaf6cde2..eb3f2708a01d 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2184,6 +2184,37 @@ out: return 0; } +/* + * Find a hole extent on given inode and change start/len to the end of hole + * extent.(hole/vacuum extent whose em->start <= start && + * em->start + em->len > start) + * When a hole extent is found, return 1 and modify start/len. + */ +static int find_first_non_hole(struct inode *inode, u64 *start, u64 *len) +{ + struct extent_map *em; + int ret = 0; + + em = btrfs_get_extent(inode, NULL, 0, *start, *len, 0); + if (IS_ERR_OR_NULL(em)) { + if (!em) + ret = -ENOMEM; + else + ret = PTR_ERR(em); + return ret; + } + + /* Hole or vacuum extent(only exists in no-hole mode) */ + if (em->block_start == EXTENT_MAP_HOLE) { + ret = 1; + *len = em->start + em->len > *start + *len ? + 0 : *start + *len - em->start - em->len; + *start = em->start + em->len; + } + free_extent_map(em); + return ret; +} + static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) { struct btrfs_root *root = BTRFS_I(inode)->root; @@ -2191,17 +2222,18 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) struct btrfs_path *path; struct btrfs_block_rsv *rsv; struct btrfs_trans_handle *trans; - u64 lockstart = round_up(offset, BTRFS_I(inode)->root->sectorsize); - u64 lockend = round_down(offset + len, - BTRFS_I(inode)->root->sectorsize) - 1; - u64 cur_offset = lockstart; + u64 lockstart; + u64 lockend; + u64 tail_start; + u64 tail_len; + u64 orig_start = offset; + u64 cur_offset; u64 min_size = btrfs_calc_trunc_metadata_size(root, 1); u64 drop_end; int ret = 0; int err = 0; int rsv_count; - bool same_page = ((offset >> PAGE_CACHE_SHIFT) == - ((offset + len - 1) >> PAGE_CACHE_SHIFT)); + bool same_page; bool no_holes = btrfs_fs_incompat(root->fs_info, NO_HOLES); u64 ino_size; @@ -2211,6 +2243,21 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) mutex_lock(&inode->i_mutex); ino_size = round_up(inode->i_size, PAGE_CACHE_SIZE); + ret = find_first_non_hole(inode, &offset, &len); + if (ret < 0) + goto out_only_mutex; + if (ret && !len) { + /* Already in a large hole */ + ret = 0; + goto out_only_mutex; + } + + lockstart = round_up(offset , BTRFS_I(inode)->root->sectorsize); + lockend = round_down(offset + len, + BTRFS_I(inode)->root->sectorsize) - 1; + same_page = ((offset >> PAGE_CACHE_SHIFT) == + ((offset + len - 1) >> PAGE_CACHE_SHIFT)); + /* * We needn't truncate any page which is beyond the end of the file * because we are sure there is no data there. @@ -2222,8 +2269,7 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) if (same_page && len < PAGE_CACHE_SIZE) { if (offset < ino_size) ret = btrfs_truncate_page(inode, offset, len, 0); - mutex_unlock(&inode->i_mutex); - return ret; + goto out_only_mutex; } /* zero back part of the first page */ @@ -2235,12 +2281,39 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) } } - /* zero the front end of the last page */ - if (offset + len < ino_size) { - ret = btrfs_truncate_page(inode, offset + len, 0, 1); - if (ret) { - mutex_unlock(&inode->i_mutex); - return ret; + /* Check the aligned pages after the first unaligned page, + * if offset != orig_start, which means the first unaligned page + * including serveral following pages are already in holes, + * the extra check can be skipped */ + if (offset == orig_start) { + /* after truncate page, check hole again */ + len = offset + len - lockstart; + offset = lockstart; + ret = find_first_non_hole(inode, &offset, &len); + if (ret < 0) + goto out_only_mutex; + if (ret && !len) { + ret = 0; + goto out_only_mutex; + } + lockstart = offset; + } + + /* Check the tail unaligned part is in a hole */ + tail_start = lockend + 1; + tail_len = offset + len - tail_start; + if (tail_len) { + ret = find_first_non_hole(inode, &tail_start, &tail_len); + if (unlikely(ret < 0)) + goto out_only_mutex; + if (!ret) { + /* zero the front end of the last page */ + if (tail_start + tail_len < ino_size) { + ret = btrfs_truncate_page(inode, + tail_start + tail_len, 0, 1); + if (ret) + goto out_only_mutex; + } } } @@ -2314,6 +2387,8 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) BUG_ON(ret); trans->block_rsv = rsv; + cur_offset = lockstart; + len = lockend - cur_offset; while (cur_offset < lockend) { ret = __btrfs_drop_extents(trans, root, inode, path, cur_offset, lockend + 1, @@ -2354,6 +2429,14 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) rsv, min_size); BUG_ON(ret); /* shouldn't happen */ trans->block_rsv = rsv; + + ret = find_first_non_hole(inode, &cur_offset, &len); + if (unlikely(ret < 0)) + break; + if (ret && !len) { + ret = 0; + break; + } } if (ret) { @@ -2392,6 +2475,7 @@ out_free: out: unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend, &cached_state, GFP_NOFS); +out_only_mutex: mutex_unlock(&inode->i_mutex); if (ret && !err) err = ret; |