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ocfs2/dlm: fix race between dispatched_work and dlm_lockres_grab_inflight_worker

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Commit ac4fef4d23 ("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>
This commit is contained in:
Joseph Qi 2014-12-18 16:17:34 -08:00 committed by Linus Torvalds
parent f62f12b3a4
commit 1e58958160
1 changed files with 3 additions and 9 deletions
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12
fs/ocfs2/dlm/dlmmaster.c
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@ -695,14 +695,6 @@ void __dlm_lockres_grab_inflight_worker(struct dlm_ctxt *dlm,
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 @@ int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data,
}
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 @@ int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data,
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);