btrfs: fix error handling in btrfs_del_csums

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>

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 4f919628137cb2162d1287af8c7b63ce0977c9dc..374d91830a900aa88718af5329deb9cd04ba1f53 100644 (file)
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -608,7 +608,7 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans,
        u64 end_byte = bytenr + len;
        u64 csum_end;
        struct extent_buffer *leaf;
-       int ret;
+       int ret = 0;
        u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
        int blocksize_bits = root->fs_info->sb->s_blocksize_bits;
 
@@ -626,6 +626,7 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans,
                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]--;
@@ -656,7 +657,7 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans,
                if (key.offset >= bytenr && csum_end <= end_byte) {
                        ret = btrfs_del_item(trans, root, path);
                        if (ret)
-                               goto out;
+                               break;
                        if (key.offset == bytenr)
                                break;
                } else if (key.offset < bytenr && csum_end > end_byte) {
@@ -700,8 +701,9 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans,
                        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 {
@@ -711,8 +713,6 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans,
                }
                btrfs_release_path(path);
        }
-       ret = 0;
-out:
        btrfs_free_path(path);
        return ret;
 }