From: Wengang Wang Date: Fri, 16 Jul 2010 15:13:33 +0000 (+0800) Subject: ocfs2/dlm: fix a dead lock X-Git-Tag: firefly_0821_release~10186^2~1106 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1bc668d6789ba22cf7d77a2cae59e53e5ef0ffc4;p=firefly-linux-kernel-4.4.55.git ocfs2/dlm: fix a dead lock commit 6d98c3ccb52f692f1a60339dde7c700686a5568b upstream. 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 Signed-off-by: Joel Becker Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c index 83bcaf266b35..8c54014cbddc 100644 --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -3046,8 +3046,6 @@ 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) { @@ -3065,14 +3063,15 @@ 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) {