linux-kernel - [PATCH 3.10 051/143] ocfs2/dlm: fix BUG in dlm_move_lockres_to_recovery

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Date:	Sun,  5 Jun 2016 12:19:14 +0200
From:	Willy Tarreau <w@....eu>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Joseph Qi <joseph.qi@...wei.com>,
	Junxiao Bi <junxiao.bi@...cle.com>,
	Mark Fasheh <mfasheh@...e.de>,
	Joel Becker <jlbec@...lplan.org>,
	Tariq Saeed <tariq.x.saeed@...cle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Willy Tarreau <w@....eu>
Subject: [PATCH 3.10 051/143] ocfs2/dlm: fix BUG in dlm_move_lockres_to_recovery_list

From: Joseph Qi <joseph.qi@...wei.com>

commit be12b299a83fc807bbaccd2bcb8ec50cbb0cb55c upstream.

When master handles convert request, it queues ast first and then
returns status.  This may happen that the ast is sent before the request
status because the above two messages are sent by two threads.  And
right after the ast is sent, if master down, it may trigger BUG in
dlm_move_lockres_to_recovery_list in the requested node because ast
handler moves it to grant list without clear lock->convert_pending.  So
remove BUG_ON statement and check if the ast is processed in
dlmconvert_remote.

Signed-off-by: Joseph Qi <joseph.qi@...wei.com>
Reported-by: Yiwen Jiang <jiangyiwen@...wei.com>
Cc: Junxiao Bi <junxiao.bi@...cle.com>
Cc: Mark Fasheh <mfasheh@...e.de>
Cc: Joel Becker <jlbec@...lplan.org>
Cc: Tariq Saeed <tariq.x.saeed@...cle.com>
Cc: Junxiao Bi <junxiao.bi@...cle.com>
Cc: <stable@...r.kernel.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Willy Tarreau <w@....eu>
---
 fs/ocfs2/dlm/dlmconvert.c  | 13 +++++++++++++
 fs/ocfs2/dlm/dlmrecovery.c |  1 -
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/fs/ocfs2/dlm/dlmconvert.c b/fs/ocfs2/dlm/dlmconvert.c
index 093200f..f65bdcf 100644
--- a/fs/ocfs2/dlm/dlmconvert.c
+++ b/fs/ocfs2/dlm/dlmconvert.c
@@ -291,6 +291,19 @@ enum dlm_status dlmconvert_remote(struct dlm_ctxt *dlm,
 		status = DLM_DENIED;
 		goto bail;
 	}
+
+	if (lock->ml.type == type && lock->ml.convert_type == LKM_IVMODE) {
+		mlog(0, "last convert request returned DLM_RECOVERING, but "
+		     "owner has already queued and sent ast to me. res %.*s, "
+		     "(cookie=%u:%llu, type=%d, conv=%d)\n",
+		     res->lockname.len, res->lockname.name,
+		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
+		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
+		     lock->ml.type, lock->ml.convert_type);
+		status = DLM_NORMAL;
+		goto bail;
+	}
+
 	res->state |= DLM_LOCK_RES_IN_PROGRESS;
 	/* move lock to local convert queue */
 	/* do not alter lock refcount.  switching lists. */
diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
index 01c69f2..33e9d70 100644
--- a/fs/ocfs2/dlm/dlmrecovery.c
+++ b/fs/ocfs2/dlm/dlmrecovery.c
@@ -2034,7 +2034,6 @@ void dlm_move_lockres_to_recovery_list(struct dlm_ctxt *dlm,
 			dlm_lock_get(lock);
 			if (lock->convert_pending) {
 				/* move converting lock back to granted */
-				BUG_ON(i != DLM_CONVERTING_LIST);
 				mlog(0, "node died with convert pending "
 				     "on %.*s. move back to granted list.\n",
 				     res->lockname.len, res->lockname.name);
-- 
2.8.0.rc2.1.gbe9624a