linux-kernel - [PATCH 4.9 42/72] NFSv4.1 fix infinite loop on IO BAD

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Message-Id: <20170406083621.741870830@linuxfoundation.org>
Date:   Thu,  6 Apr 2017 10:38:29 +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, Olga Kornievskaia <kolga@...app.com>,
        Anna Schumaker <Anna.Schumaker@...app.com>
Subject: [PATCH 4.9 42/72] NFSv4.1 fix infinite loop on IO BAD_STATEID error

4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Olga Kornievskaia <kolga@...app.com>

commit 0e3d3e5df07dcf8a50d96e0ecd6ab9a888f55dfc upstream.

Commit 63d63cbf5e03 "NFSv4.1: Don't recheck delegations that
have already been checked" introduced a regression where when a
client received BAD_STATEID error it would not send any TEST_STATEID
and instead go into an infinite loop of resending the IO that caused
the BAD_STATEID.

Fixes: 63d63cbf5e03 ("NFSv4.1: Don't recheck delegations that have already been checked")
Signed-off-by: Olga Kornievskaia <kolga@...app.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@...app.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/nfs/nfs4proc.c |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2532,17 +2532,14 @@ static void nfs41_check_delegation_state
 	}
 
 	nfs4_stateid_copy(&stateid, &delegation->stateid);
-	if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
+	if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) ||
+		!test_and_clear_bit(NFS_DELEGATION_TEST_EXPIRED,
+			&delegation->flags)) {
 		rcu_read_unlock();
 		nfs_finish_clear_delegation_stateid(state, &stateid);
 		return;
 	}
 
-	if (!test_and_clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags)) {
-		rcu_read_unlock();
-		return;
-	}
-
 	cred = get_rpccred(delegation->cred);
 	rcu_read_unlock();
 	status = nfs41_test_and_free_expired_stateid(server, &stateid, cred);