ocfs2/dlm: fix race between dispatched_work and dlm_lockres_grab_inflight_worker
Commit 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@huawei.com>
Signed-off-by: Xue jiufei <xuejiufei@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
index 3689b35..a6944b2 100644
--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -695,14 +695,6 @@
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)
{
@@ -1646,6 +1638,7 @@
}
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) {
@@ -1653,7 +1646,8 @@
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);