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From: Yihao Wu <wuyihao@linux.alibaba.com>
To: linux-nfs@vger.kernel.org, Jeff Layton <jlayton@kernel.org>,
	"J. Bruce Fields" <bfields@fieldses.org>
Cc: stable@vger.kernel.org, Joseph Qi <joseph.qi@linux.alibaba.com>,
	caspar@linux.alibaba.com
Subject: [PATCH 2/2] NFSv4.1: Fix bug only the first CB_NOTIFY_LOCK is handled
Date: Wed, 8 May 2019 17:15:03 +0800	[thread overview]
Message-ID: <cdba66b5-29a3-e37b-1e0f-808c171d09c3@linux.alibaba.com> (raw)
In-Reply-To: <2a1cebca-1efb-1686-475b-a581e50e61b4@linux.alibaba.com>

When the first CB_NOTIFY_LOCK wakes a waiter, it can still fail to
acquire the lock. Then it might goes to sleep again. However it's removed
from the wait queue and not put back. So when the CB_NOTIFY_LOCK comes
again, it fails to wake this waiter.

Signed-off-by: Yihao Wu <wuyihao@linux.alibaba.com>
---
 fs/nfs/nfs4proc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index f13ea09..9de2c2d 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6932,6 +6932,10 @@ struct nfs4_lock_waiter {
 
 		status = -ERESTARTSYS;
 		wait_woken(&wait, TASK_INTERRUPTIBLE, NFS4_LOCK_MAXTIMEOUT);
+		if (!signalled())  {
+			finish_wait(q, &wait);
+			add_wait_queue(q, &wait);
+		}
 	}
 
 	finish_wait(q, &wait);
-- 
1.8.3.1



  reply	other threads:[~2019-05-08  9:15 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-08  9:11 [PATCH 0/2] Fix two bugs CB_NOTIFY_LOCK failing to wake a water Yihao Wu
2019-05-08  9:13 ` [PATCH 1/2] NFSv4.1: Again fix a race where CB_NOTIFY_LOCK fails to wake a waiter Yihao Wu
2019-05-08  9:15   ` Yihao Wu [this message]
2019-05-08  9:23     ` [PATCH 2/2] NFSv4.1: Fix bug only the first CB_NOTIFY_LOCK is handled Greg KH
2019-05-08  9:19   ` [PATCH 1/2] NFSv4.1: Again fix a race where CB_NOTIFY_LOCK fails to wake a waiter Greg KH
2019-05-08  9:39     ` Yihao Wu
2019-05-08 12:24   ` Jeff Layton
2019-05-08 18:18     ` Yihao Wu

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