diff options
Diffstat (limited to 'fs/btrfs/ctree.c')
| -rw-r--r-- | fs/btrfs/ctree.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index da519c1b6ad0..617d4827eec2 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -367,7 +367,8 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans, /* * check if the tree block can be shared by multiple trees */ -int btrfs_block_can_be_shared(struct btrfs_root *root, +int btrfs_block_can_be_shared(struct btrfs_trans_handle *trans, + struct btrfs_root *root, struct extent_buffer *buf) { /* @@ -376,11 +377,21 @@ int btrfs_block_can_be_shared(struct btrfs_root *root, * not allocated by tree relocation, we know the block is not shared. */ if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && - buf != root->node && buf != root->commit_root && + buf != root->node && (btrfs_header_generation(buf) <= btrfs_root_last_snapshot(&root->root_item) || - btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) - return 1; + btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) { + if (buf != root->commit_root) + return 1; + /* + * An extent buffer that used to be the commit root may still be + * shared because the tree height may have increased and it + * became a child of a higher level root. This can happen when + * snapshotting a subvolume created in the current transaction. + */ + if (btrfs_header_generation(buf) == trans->transid) + return 1; + } return 0; } @@ -415,7 +426,7 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, * are only allowed for blocks use full backrefs. */ - if (btrfs_block_can_be_shared(root, buf)) { + if (btrfs_block_can_be_shared(trans, root, buf)) { ret = btrfs_lookup_extent_info(trans, fs_info, buf->start, btrfs_header_level(buf), 1, &refs, &flags); |