From b5560143385e18b4109ad6951c7719705e3dd995 Mon Sep 17 00:00:00 2001 From: jiangyiwen Date: Thu, 14 Jan 2016 15:17:23 -0800 Subject: [PATCH] ocfs2/dlm: wait until DLM_LOCK_RES_SETREF_INPROG is cleared in dlm_deref_lockres_worker Commit f3f854648de6 ("ocfs2_dlm: Ensure correct ordering of set/clear refmap bit on lockres") still exists a race which can't ensure the ordering is exactly correct. Node1 Node2 Node3 umount, migrate lockres to Node2 migrate finished, send migrate request to Node3 received migrate request, create a migration_mle, respond to Node2. set DLM_LOCK_RES_SETREF_INPROG and send assert master to Node3 delete migration_mle in assert_master_handler, Node3 umount without response dlm_thread purge this lockres, send drop deref message to Node2 found the flag of DLM_LOCK_RES_SETREF_INPROG is set, dispatch dlm_deref_lockres_worker to clear refmap, but in function of dlm_deref_lockres_worker, only if node in refmap it wait DLM_LOCK_RES_SETREF_INPROG to be cleared. So worker is done successfully purge lockres, send assert master response to Node1, and finish umount set Node3 in refmap, and it won't be cleared forever, thus lead to umount hung so wait until DLM_LOCK_RES_SETREF_INPROG is cleared in dlm_deref_lockres_worker. Signed-off-by: Yiwen Jiang Reviewed-by: Joseph Qi Reviewed-by: Junxiao Bi Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/dlm/dlmmaster.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c index 84f2f8079466..1fc172f89872 100644 --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -2388,8 +2388,8 @@ static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data) spin_lock(&res->spinlock); BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF); + __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG); if (test_bit(node, res->refmap)) { - __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG); dlm_lockres_clear_refmap_bit(dlm, res, node); cleared = 1; } -- 2.30.2