diff options
| -rw-r--r-- | fs/btrfs/file.c | 39 |
1 files changed, 30 insertions, 9 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index c2e83babdb8d..bc1e00db96c9 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -984,8 +984,8 @@ int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos, struct btrfs_root *root = inode->root; struct extent_state *cached_state = NULL; u64 lockstart, lockend; - u64 num_bytes; - int ret; + u64 cur_offset; + int ret = 0; if (!(inode->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC))) return 0; @@ -996,7 +996,6 @@ int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos, lockstart = round_down(pos, fs_info->sectorsize); lockend = round_up(pos + *write_bytes, fs_info->sectorsize) - 1; - num_bytes = lockend - lockstart + 1; if (nowait) { if (!btrfs_try_lock_ordered_range(inode, lockstart, lockend, @@ -1008,14 +1007,36 @@ int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos, btrfs_lock_and_flush_ordered_range(inode, lockstart, lockend, &cached_state); } - ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, nowait); - if (ret <= 0) - btrfs_drew_write_unlock(&root->snapshot_lock); - else - *write_bytes = min_t(size_t, *write_bytes , - num_bytes - pos + lockstart); + + cur_offset = lockstart; + while (cur_offset < lockend) { + u64 num_bytes = lockend - cur_offset + 1; + + ret = can_nocow_extent(inode, cur_offset, &num_bytes, NULL, nowait); + if (ret <= 0) { + /* + * If cur_offset == lockstart it means we haven't found + * any extent against which we can NOCOW, so unlock the + * snapshot lock. + */ + if (cur_offset == lockstart) + btrfs_drew_write_unlock(&root->snapshot_lock); + break; + } + cur_offset += num_bytes; + } + btrfs_unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state); + /* + * cur_offset > lockstart means there's at least a partial range we can + * NOCOW, and that range can cover one or more extents. + */ + if (cur_offset > lockstart) { + *write_bytes = min_t(size_t, *write_bytes, cur_offset - pos); + return 1; + } + return ret; } |