[Ocfs2-devel] [patch 08/10] ocfs2/dlm: fix race between dispatched_work and dlm_lockres_grab_inflight_worker
akpm at linux-foundation.org
akpm at linux-foundation.org
Wed Aug 6 13:32:15 PDT 2014
From: Joseph Qi <joseph.qi at huawei.com>
Subject: ocfs2/dlm: fix race between dispatched_work and dlm_lockres_grab_inflight_worker
ac4fef4d23ed ("ocfs2/dlm: do not purge lockres that is queued for assert
master") may have the following possible race case:
dlm_dispatch_assert_master dlm_wq
========================================================================
queue_work(dlm->quedlm_worker,
&dlm->dispatched_work);
dispatch work,
dlm_lockres_drop_inflight_worker
*BUG_ON(res->inflight_assert_workers == 0)*
dlm_lockres_grab_inflight_worker
inflight_assert_workers++
So ensure inflight_assert_workers to be increased first.
Signed-off-by: Joseph Qi <joseph.qi at huawei.com>
Signed-off-by: Xue jiufei <xuejiufei at huawei.com>
Cc: Joel Becker <jlbec at evilplan.org>
Cc: Mark Fasheh <mfasheh at suse.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
---
fs/ocfs2/dlm/dlmmaster.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff -puN fs/ocfs2/dlm/dlmmaster.c~ocfs2-dlm-fix-race-between-dispatched_work-and-dlm_lockres_grab_inflight_worker fs/ocfs2/dlm/dlmmaster.c
--- a/fs/ocfs2/dlm/dlmmaster.c~ocfs2-dlm-fix-race-between-dispatched_work-and-dlm_lockres_grab_inflight_worker
+++ a/fs/ocfs2/dlm/dlmmaster.c
@@ -684,14 +684,6 @@ void __dlm_lockres_grab_inflight_worker(
res->inflight_assert_workers);
}
-static void dlm_lockres_grab_inflight_worker(struct dlm_ctxt *dlm,
- struct dlm_lock_resource *res)
-{
- spin_lock(&res->spinlock);
- __dlm_lockres_grab_inflight_worker(dlm, res);
- spin_unlock(&res->spinlock);
-}
-
static void __dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res)
{
@@ -1625,6 +1617,7 @@ send_response:
}
mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
dlm->node_num, res->lockname.len, res->lockname.name);
+ spin_lock(&res->spinlock);
ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
DLM_ASSERT_MASTER_MLE_CLEANUP);
if (ret < 0) {
@@ -1632,7 +1625,8 @@ send_response:
response = DLM_MASTER_RESP_ERROR;
dlm_lockres_put(res);
} else
- dlm_lockres_grab_inflight_worker(dlm, res);
+ __dlm_lockres_grab_inflight_worker(dlm, res);
+ spin_unlock(&res->spinlock);
} else {
if (res)
dlm_lockres_put(res);
_
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