From 6d98c3ccb52f692f1a60339dde7c700686a5568b Mon Sep 17 00:00:00 2001 From: Wengang Wang Date: Fri, 16 Jul 2010 23:13:33 +0800 Subject: [PATCH] ocfs2/dlm: fix a dead lock When we have to take both dlm->master_lock and lockres->spinlock, take them in order lockres->spinlock and then dlm->master_lock. The patch fixes a violation of the rule. We can simply move taking dlm->master_lock to where we have dropped res->spinlock since when we access res->state and free mle memory we don't need master_lock's protection. Signed-off-by: Wengang Wang Cc: stable@kernel.org Signed-off-by: Joel Becker --- fs/ocfs2/dlm/dlmmaster.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c index 94b97fc6a88e..6d098b89d46e 100644 --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -3050,8 +3050,6 @@ int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data, /* check for pre-existing lock */ spin_lock(&dlm->spinlock); res = __dlm_lookup_lockres(dlm, name, namelen, hash); - spin_lock(&dlm->master_lock); - if (res) { spin_lock(&res->spinlock); if (res->state & DLM_LOCK_RES_RECOVERING) { @@ -3069,14 +3067,15 @@ int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data, spin_unlock(&res->spinlock); } + spin_lock(&dlm->master_lock); /* ignore status. only nonzero status would BUG. */ ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name, namelen, migrate->new_master, migrate->master); -unlock: spin_unlock(&dlm->master_lock); +unlock: spin_unlock(&dlm->spinlock); if (oldmle) {