diff options
| -rw-r--r-- | fs/btrfs/backref.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index f846fec08c86..90e40d5ceccd 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1872,6 +1872,8 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr, .have_delayed_delete_refs = false, }; int level; + bool leaf_cached; + bool leaf_is_shared; for (int i = 0; i < BTRFS_BACKREF_CTX_PREV_EXTENTS_SIZE; i++) { if (ctx->prev_extents_cache[i].bytenr == bytenr) @@ -1893,6 +1895,23 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr, walk_ctx.time_seq = elem.seq; } + ctx->use_path_cache = true; + + /* + * We may have previously determined that the current leaf is shared. + * If it is, then we have a data extent that is shared due to a shared + * subtree (caused by snapshotting) and we don't need to check for data + * backrefs. If the leaf is not shared, then we must do backref walking + * to determine if the data extent is shared through reflinks. + */ + leaf_cached = lookup_backref_shared_cache(ctx, root, + ctx->curr_leaf_bytenr, 0, + &leaf_is_shared); + if (leaf_cached && leaf_is_shared) { + ret = 1; + goto out_trans; + } + walk_ctx.ignore_extent_item_pos = true; walk_ctx.trans = trans; walk_ctx.fs_info = fs_info; @@ -1901,7 +1920,6 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr, /* -1 means we are in the bytenr of the data extent. */ level = -1; ULIST_ITER_INIT(&uiter); - ctx->use_path_cache = true; while (1) { bool is_shared; bool cached; @@ -1972,6 +1990,7 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr, ctx->prev_extents_cache_slot = slot; } +out_trans: if (trans) { btrfs_put_tree_mod_seq(fs_info, &elem); btrfs_end_transaction(trans); |