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| author | Wengang Wang <wen.gang.wang@oracle.com> | 2010-07-16 23:13:33 +0800 |
|---|---|---|
| committer | Joel Becker <joel.becker@oracle.com> | 2010-08-07 10:44:20 -0700 |
| commit | 6d98c3ccb52f692f1a60339dde7c700686a5568b (patch) | |
| tree | c43eabf9914d413d49d0bb650314295ac9e613c2 | |
| parent | 6eda3dd33f8a0ce58ee56a11351758643a698db4 (diff) | |
| download | linux-stable-6d98c3ccb52f692f1a60339dde7c700686a5568b.tar.gz linux-stable-6d98c3ccb52f692f1a60339dde7c700686a5568b.tar.bz2 linux-stable-6d98c3ccb52f692f1a60339dde7c700686a5568b.zip | |
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 <wen.gang.wang@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Joel Becker <joel.becker@oracle.com>
| -rw-r--r-- | fs/ocfs2/dlm/dlmmaster.c | 5 |
1 files 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) { |