[PATCH 4.19 36/58] btrfs: fix error handling in btrfs_del_csums

Greg Kroah-Hartman
2021-06-08T18:39:53Z

From: Josef Bacik <josef@toxicpanda.com>

commit b86652be7c83f70bf406bed18ecf55adb9bfb91b upstream.

Error injection stress would sometimes fail with checksums on disk that
did not have a corresponding extent. This occurred because the pattern
in btrfs_del_csums was

while (1) {
ret = btrfs_search_slot();
if (ret < 0)
break;
}
ret = 0;
out:
btrfs_free_path(path);
return ret;

If we got an error from btrfs_search_slot we'd clear the error because
we were breaking instead of goto out. Instead of using goto out, simply
handle the cases where we may leave a random value in ret, and get rid
of the

ret = 0;
out:

pattern and simply allow break to have the proper error reporting. With
this fix we properly abort the transaction and do not commit thinking we
successfully deleted the csum.

Reviewed-by: Qu Wenruo <wqu@suse.com>
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/file-item.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -586,7 +586,7 @@ int btrfs_del_csums(struct btrfs_trans_h
u64 end_byte = bytenr + len;
u64 csum_end;
struct extent_buffer *leaf;
- int ret;
+ int ret = 0;
u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
int blocksize_bits = fs_info->sb->s_blocksize_bits;

@@ -605,6 +605,7 @@ int btrfs_del_csums(struct btrfs_trans_h
path->leave_spinning = 1;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0) {
+ ret = 0;
if (path->slots[0] == 0)
break;
path->slots[0]--;
@@ -661,7 +662,7 @@ int btrfs_del_csums(struct btrfs_trans_h
ret = btrfs_del_items(trans, root, path,
path->slots[0], del_nr);
if (ret)
- goto out;
+ break;
if (key.offset == bytenr)
break;
} else if (key.offset < bytenr && csum_end > end_byte) {
@@ -705,8 +706,9 @@ int btrfs_del_csums(struct btrfs_trans_h
ret = btrfs_split_item(trans, root, path, &key, offset);
if (ret && ret != -EAGAIN) {
btrfs_abort_transaction(trans, ret);
- goto out;
+ break;
}
+ ret = 0;

key.offset = end_byte - 1;
} else {
@@ -716,8 +718,6 @@ int btrfs_del_csums(struct btrfs_trans_h
}
btrfs_release_path(path);
}
- ret = 0;
-out:
btrfs_free_path(path);
return ret;
}