For tree reloc tree root, its backref points to it self.
So for such case, we should finish the lookup.
Previous end condition is to ensure it's tree reloc tree *and* needs its
root bytenr to match the bytenr passed in.
However the @root passed in can be other tree, e.g. other tree reloc
tree which shares the node/leaf.
This makes any check based on @root passed in invalid.
The patch removes the unreliable root objectid detection, and only use
root->bytenr check.
For the possibility of invalid self-pointing backref, extent tree
checker should have already handled it, so we don't need to bother in
fs tree checker.
Fixes: 54c8f9152fd9 ("btrfs-progs: check: Fix lowmem mode stack overflow caused by fsck/023")
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
cmds-check.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/cmds-check.c b/cmds-check.c
index b9943a0d3a0f..36e4a91b7e17 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -10251,15 +10251,10 @@ static int check_tree_block_ref(struct btrfs_root *root,
u32 nodesize = root->fs_info->nodesize;
u32 item_size;
u64 offset;
- int tree_reloc_root = 0;
int found_ref = 0;
int err = 0;
int ret;
- if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
- btrfs_header_bytenr(root->node) == bytenr)
- tree_reloc_root = 1;
-
btrfs_init_path(&path);
key.objectid = bytenr;
if (btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
@@ -10350,8 +10345,12 @@ static int check_tree_block_ref(struct btrfs_root *root,
/*
* Backref of tree reloc root points to itself, no need
* to check backref any more.
+ *
+ * This may be an error of loop backref, but extent tree
+ * checker should have already handled it.
+ * Here we only need to avoid infinite iteration.
*/
- if (tree_reloc_root)
+ if (offset == bytenr)
found_ref = 1;
else
/* Check if the backref points to valid referencer */
--
2.15.0
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