btrfs: set the correct lockdep class for new nodes

When flipping over to the rw_semaphore I noticed I'd get a lockdep splat
in replace_path(), which is weird because we're swapping the reloc root
with the actual target root.  Turns out this is because we're using the
root->root_key.objectid as the root id for the newly allocated tree
block when setting the lockdep class, however we need to be using the
actual owner of this new block, which is saved in owner.

The affected path is through btrfs_copy_root as all other callers of
btrfs_alloc_tree_block (which calls init_new_buffer) have root_objectid
== root->root_key.objectid .

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 5871ef78edbac4bcc363347f8875b266015cda94..e9eedc053fc52c7ee120f352766b129c2bcb1a70 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4527,7 +4527,7 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                return ERR_PTR(-EUCLEAN);
        }
 
-       btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
+       btrfs_set_buffer_lockdep_class(owner, buf, level);
        btrfs_tree_lock(buf);
        btrfs_clean_tree_block(buf);
        clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);