linux-kernel - [PATCH 5.12 168/173] NFSv4: Fix second deadlock in nfs4_evict

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Message-Id: <20210614102703.769620310@linuxfoundation.org>
Date:   Mon, 14 Jun 2021 12:28:20 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Trond Myklebust <trond.myklebust@...merspace.com>
Subject: [PATCH 5.12 168/173] NFSv4: Fix second deadlock in nfs4_evict_inode()

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

commit c3aba897c6e67fa464ec02b1f17911577d619713 upstream.

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: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/nfs/nfs4proc.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9630,15 +9630,20 @@ int nfs4_proc_layoutreturn(struct nfs4_l
 			&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);