btrfs: do not delete mismatched root refs

commit 423a716cd7be16fb08690760691befe3be97d3fc upstream.

btrfs_del_root_ref() will simply WARN_ON() if the ref doesn't match in
any way, and then continue to delete the reference.  This shouldn't
happen, we have these values because there's more to the reference than
the original root and the sub root.  If any of these checks fail, return
-ENOENT.

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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 360a728a639fec403893c6847e1f7859a47dff13..9bdcae8336ffb36ceb0ccab31d4afe6ed58fb158 100644 (file)
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -373,11 +373,13 @@ again:
                leaf = path->nodes[0];
                ref = btrfs_item_ptr(leaf, path->slots[0],
                                     struct btrfs_root_ref);
-
-               WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
-               WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
                ptr = (unsigned long)(ref + 1);
-               WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
+               if ((btrfs_root_ref_dirid(leaf, ref) != dirid) ||
+                   (btrfs_root_ref_name_len(leaf, ref) != name_len) ||
+                   memcmp_extent_buffer(leaf, name, ptr, name_len)) {
+                       err = -ENOENT;
+                       goto out;
+               }
                *sequence = btrfs_root_ref_sequence(leaf, ref);
 
                ret = btrfs_del_item(trans, tree_root, path);