btrfs: free data reloc tree on failed mount

While testing a weird problem with -o degraded, I noticed I was getting
leaked root errors

  BTRFS warning (device loop0): writable mount is not allowed due to too many missing devices
  BTRFS error (device loop0): open_ctree failed
  BTRFS error (device loop0): leaked root -9-0 refcount 1

This is the DATA_RELOC root, which gets read before the other fs roots,
but is included in the fs roots radix tree.  Handle this by adding a
btrfs_drop_and_free_fs_root() on the data reloc root if it exists.  This
is ok to do here if we fail further up because we will only drop the ref
if we delete the root from the radix tree, and all other cleanup won't
be duplicated.

CC: stable@vger.kernel.org # 5.8+
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/disk-io.c b/fs/btrfs/disk-io.c
index 465bc8372e09906376e3ea17c9ef4f79760264a0..9fe9ec6aab7101f1ecdfede52ad3bed0f04510d8 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3441,6 +3441,8 @@ fail_block_groups:
        btrfs_put_block_group_cache(fs_info);
 
 fail_tree_roots:
+       if (fs_info->data_reloc_root)
+               btrfs_drop_and_free_fs_root(fs_info, fs_info->data_reloc_root);
        free_root_pointers(fs_info, true);
        invalidate_inode_pages2(fs_info->btree_inode->i_mapping);