Messages in this thread Patch in this message | | | Date | Tue, 24 Aug 2010 15:44:18 -0700 | From | Greg KH <> | Subject | [013/114] ocfs2/dlm: fix a dead lock |
| |
2.6.35-stable review patch. If anyone has any objections, please let us know.
------------------
From: Wengang Wang <wen.gang.wang@oracle.com>
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 <wen.gang.wang@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/ocfs2/dlm/dlmmaster.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -3050,8 +3050,6 @@ int dlm_migrate_request_handler(struct o /* 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 o 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) {
| |