[PATCH 5.16 0795/1017] btrfs: make search_csum_tree return 0 if we get -EFBIG

From: Greg Kroah-Hartman
Date: Tue Apr 05 2022 - 09:23:09 EST

From: Josef Bacik <josef@xxxxxxxxxxxxxx>

[ Upstream commit 03ddb19d2ea745228879b9334f3b550c88acb10a ]

We can either fail to find a csum entry at all and return -ENOENT, or we
can find a range that is close, but return -EFBIG. In essence these
both mean the same thing when we are doing a lookup for a csum in an
existing range, we didn't find a csum. We want to treat both of these
errors the same way, complain loudly that there wasn't a csum. This
currently happens anyway because we do

count = search_csum_tree();
if (count <= 0) {
// reloc and error handling

However it forces us to incorrectly treat EIO or ENOMEM errors as on
disk corruption. Fix this by returning 0 if we get either -ENOENT or
-EFBIG from btrfs_lookup_csum() so we can do proper error handling.

Reviewed-by: Boris Burkov <boris@xxxxxx>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
fs/btrfs/file-item.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index d1cbb64a78f3..91ae1caa1bdb 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -303,7 +303,7 @@ static int search_csum_tree(struct btrfs_fs_info *fs_info,
read_extent_buffer(path->nodes[0], dst, (unsigned long)item,
ret * csum_size);
- if (ret == -ENOENT)
+ if (ret == -ENOENT || ret == -EFBIG)
ret = 0;
return ret;