linux-kernel - [PATCH 3.16.y-ckt 013/126] Failing to send a CLOSE if file is opened WRONLY and server reboots on a 4.x mount

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Date:	Wed,  9 Dec 2015 09:36:23 +0000
From:	Luis Henriques <luis.henriques@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Olga Kornievskaia <aglo@...ch.edu>,
	Trond Myklebust <trond.myklebust@...marydata.com>,
	Ben Hutchings <ben@...adent.org.uk>,
	Luis Henriques <luis.henriques@...onical.com>
Subject: [PATCH 3.16.y-ckt 013/126] Failing to send a CLOSE if file is opened WRONLY and server reboots on a 4.x mount

3.16.7-ckt21 -stable review patch.  If anyone has any objections, please let me know.

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

From: Olga Kornievskaia <aglo@...ch.edu>

commit a41cbe86df3afbc82311a1640e20858c0cd7e065 upstream.

A test case is as the description says:
open(foobar, O_WRONLY);
sleep()  --> reboot the server
close(foobar)

The bug is because in nfs4state.c in nfs4_reclaim_open_state() a few
line before going to restart, there is
clear_bit(NFS4CLNT_RECLAIM_NOGRACE, &state->flags).

NFS4CLNT_RECLAIM_NOGRACE is a flag for the client states not open
owner states. Value of NFS4CLNT_RECLAIM_NOGRACE is 4 which is the
value of NFS_O_WRONLY_STATE in nfs4_state->flags. So clearing it wipes
out state and when we go to close it, “call_close” doesn’t get set as
state flag is not set and CLOSE doesn’t go on the wire.

Signed-off-by: Olga Kornievskaia <aglo@...ch.edu>
Signed-off-by: Trond Myklebust <trond.myklebust@...marydata.com>
Cc: Ben Hutchings <ben@...adent.org.uk>
Signed-off-by: Luis Henriques <luis.henriques@...onical.com>
---
 fs/nfs/nfs4state.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 46d876487795..577bb8d849f7 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1482,7 +1482,7 @@ restart:
 					spin_unlock(&state->state_lock);
 				}
 				nfs4_put_open_state(state);
-				clear_bit(NFS4CLNT_RECLAIM_NOGRACE,
+				clear_bit(NFS_STATE_RECLAIM_NOGRACE,
 					&state->flags);
 				spin_lock(&sp->so_lock);
 				goto restart;
--
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