From d18bcfe455106b23aa254d1da0c1a7f39b9b20fe Mon Sep 17 00:00:00 2001
From: Yihao Wu <wuyihao@linux.alibaba.com>
Date: Wed, 6 Mar 2019 21:03:50 +0800
Subject: [PATCH] nfsd: fix wrong check in write_v4_end_grace()

commit dd838821f0a29781b185cd8fb8e48d5c177bd838 upstream.

Commit 62a063b8e7d1 "nfsd4: fix crash on writing v4_end_grace before
nfsd startup" is trying to fix a NULL dereference issue, but it
mistakenly checks if the nfsd server is started. So fix it.

Fixes: 62a063b8e7d1 "nfsd4: fix crash on writing v4_end_grace before nfsd startup"
Cc: stable@vger.kernel.org
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Yihao Wu <wuyihao@linux.alibaba.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/nfsd/nfsctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 03c7a4e7b6bab..0cd57db5c5af5 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1106,7 +1106,7 @@ static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size)
 		case 'Y':
 		case 'y':
 		case '1':
-			if (nn->nfsd_serv)
+			if (!nn->nfsd_serv)
 				return -EBUSY;
 			nfsd4_end_grace(nn);
 			break;