[PATCH] nfs: fix bdi_unregister() before sb kill

[Jens Axboe <jens.axboe@oracle.com>]

Hi,

This can cause a hang on NFS umount, since the bdi gets pruned before we
flush any pending dirty IO. Peter, can you check whether it fixes your
issue?

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
--- 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);
 }

-- 
Jens Axboe