Received-SPF: pass (google.com: domain of linux-nfs-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   trondmy@kernel.org
To:     zhangxiaoxu <zhangxiaoxu5@huawei.com>
Cc:     linux-nfs@vger.kernel.org
Subject: [PATCH 2/2] NFSv4: Fix second deadlock in nfs4_evict_inode()
Date:   Tue,  1 Jun 2021 13:36:34 -0400
Message-Id: <20210601173634.243152-2-trondmy@kernel.org>
In-Reply-To: <20210601173634.243152-1-trondmy@kernel.org>
References: <20210601173634.243152-1-trondmy@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Trond Myklebust <trond.myklebust@hammerspace.com>

If the inode is being evicted but has to return a layout first, then
that too can cause a deadlock in the corner case where the server
reboots.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/nfs4proc.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 673809644981..e25c16257545 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9658,15 +9658,20 @@ int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp, bool sync)
 			&task_setup_data.rpc_client, &msg);
 
 	dprintk("--> %s\n", __func__);
+	lrp->inode = nfs_igrab_and_active(lrp->args.inode);
 	if (!sync) {
-		lrp->inode = nfs_igrab_and_active(lrp->args.inode);
 		if (!lrp->inode) {
 			nfs4_layoutreturn_release(lrp);
 			return -EAGAIN;
 		}
 		task_setup_data.flags |= RPC_TASK_ASYNC;
 	}
-	nfs4_init_sequence(&lrp->args.seq_args, &lrp->res.seq_res, 1, 0);
+	if (!lrp->inode)
+		nfs4_init_sequence(&lrp->args.seq_args, &lrp->res.seq_res, 1,
+				   1);
+	else
+		nfs4_init_sequence(&lrp->args.seq_args, &lrp->res.seq_res, 1,
+				   0);
 	task = rpc_run_task(&task_setup_data);
 	if (IS_ERR(task))
 		return PTR_ERR(task);
-- 
2.31.1