[PATCH 4.4 223/230] nfsd: fix wrong check in write_v4_end_grace()

[Greg Kroah-Hartman]

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

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

From: Yihao Wu <wuyihao@xxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx
Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Signed-off-by: Yihao Wu <wuyihao@xxxxxxxxxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/nfsd/nfsctl.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1106,7 +1106,7 @@ static ssize_t write_v4_end_grace(struct
 		case 'Y':
 		case 'y':
 		case '1':
-			if (nn->nfsd_serv)
+			if (!nn->nfsd_serv)
 				return -EBUSY;
 			nfsd4_end_grace(nn);
 			break;