linux-kernel - [PATCH AUTOSEL 5.12 18/33] NFSv4: Fix second deadlock in nfs4_evict

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Date:   Tue, 15 Jun 2021 11:48:09 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Trond Myklebust <trond.myklebust@...merspace.com>,
        Sasha Levin <sashal@...nel.org>, linux-nfs@...r.kernel.org
Subject: [PATCH AUTOSEL 5.12 18/33] NFSv4: Fix second deadlock in nfs4_evict_inode()

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

[ Upstream commit c3aba897c6e67fa464ec02b1f17911577d619713 ]

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@...merspace.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 056d98d1d1a7..420d34461bb8 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9628,15 +9628,20 @@ 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);
-- 
2.30.2