nfs: nfs_kill_super() should call bdi_unregister() after killing super

Otherwise we could be attempting to flush data for a writeback
thread and bdi that have already disappeared.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index de93569..f1cc058 100644 (file)
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2190,8 +2190,8 @@ static void nfs_kill_super(struct super_block *s)
 {
        struct nfs_server *server = NFS_SB(s);
 
-       bdi_unregister(&server->backing_dev_info);
        kill_anon_super(s);
+       bdi_unregister(&server->backing_dev_info);
        nfs_fscache_release_super_cookie(s);
        nfs_free_server(server);
 }