pNFS: Fix a typo in pnfs_update_layout

mainline inclusion
from mainline-5.1-rc1
commit 400417b05f3e
category: bugfix
bugzilla: 12777
CVE: NA

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

We're supposed to wait for the outstanding layout count to go to zero,
but that got lost somehow.

Fixes: d03360aa ("pNFS: Ensure we return the error if someone...")
Reported-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NZhangXiaoxu <zhangxiaoxu5@huawei.com>
Reviewed-by: Nzhengbin <zhengbin13@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/nfs/pnfs.c

@@ -1866,7 +1866,7 @@ pnfs_update_layout(struct inode *ino,
 	    atomic_read(&lo->plh_outstanding) != 0) {
 		spin_unlock(&ino->i_lock);
 		lseg = ERR_PTR(wait_var_event_killable(&lo->plh_outstanding,
-					atomic_read(&lo->plh_outstanding)));
+					!atomic_read(&lo->plh_outstanding)));
 		if (IS_ERR(lseg) || !list_empty(&lo->plh_segs))
 			goto out_put_layout_hdr;
 		pnfs_put_layout_hdr(lo);