[PATCH 4.4 06/34] sget(): handle failures of register_shrinker()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Al Viro <viro@zeniv.linux.org.uk>


[ Upstream commit 9ee332d99e4d5a97548943b81c54668450ce641b ]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/super.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/fs/super.c
+++ b/fs/super.c
@@ -497,7 +497,11 @@ retry:
 	hlist_add_head(&s->s_instances, &type->fs_supers);
 	spin_unlock(&sb_lock);
 	get_filesystem(type);
-	register_shrinker(&s->s_shrink);
+	err = register_shrinker(&s->s_shrink);
+	if (err) {
+		deactivate_locked_super(s);
+		s = ERR_PTR(err);
+	}
 	return s;
 }