btrfs: do not leak reloc root if we fail to read the fs root

commit ca1aa2818a53875cfdd175fb5e9a2984e997cce9 upstream.

If we fail to read the fs root corresponding with a reloc root we'll
just break out and free the reloc roots.  But we remove our current
reloc_root from this list higher up, which means we'll leak this
reloc_root.  Fix this by adding ourselves back to the reloc_roots list
so we are properly cleaned up.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
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/relocation.c b/fs/btrfs/relocation.c
index b0c3a6a..b106d36 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4587,6 +4587,7 @@
 				       reloc_root->root_key.offset);
 		if (IS_ERR(fs_root)) {
 			err = PTR_ERR(fs_root);
+			list_add_tail(&reloc_root->root_list, &reloc_roots);
 			goto out_free;
 		}