ocfs2_dlm: Fix lockres ref counting bug
During umount, the umount thread migrates the lockres' and the dlm_thread
frees the empty lockres'. Due to a race, the reference counting on the
lockres goes awry leading to extra puts.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
index 6087c47..dbbac18 100644
--- a/fs/ocfs2/dlm/dlmdomain.c
+++ b/fs/ocfs2/dlm/dlmdomain.c
@@ -138,8 +138,10 @@
void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
{
- hlist_del_init(&lockres->hash_node);
- dlm_lockres_put(lockres);
+ if (!hlist_unhashed(&lockres->hash_node)) {
+ hlist_del_init(&lockres->hash_node);
+ dlm_lockres_put(lockres);
+ }
}
void __dlm_insert_lockres(struct dlm_ctxt *dlm,
diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c
index 6421a8f..2b264c6 100644
--- a/fs/ocfs2/dlm/dlmthread.c
+++ b/fs/ocfs2/dlm/dlmthread.c
@@ -256,20 +256,14 @@
break;
}
- mlog(0, "removing lockres %.*s:%p from purgelist\n",
- lockres->lockname.len, lockres->lockname.name, lockres);
- list_del_init(&lockres->purge);
- dlm_lockres_put(lockres);
- dlm->purge_count--;
+ dlm_lockres_get(lockres);
/* This may drop and reacquire the dlm spinlock if it
* has to do migration. */
- mlog(0, "calling dlm_purge_lockres!\n");
- dlm_lockres_get(lockres);
if (dlm_purge_lockres(dlm, lockres))
BUG();
+
dlm_lockres_put(lockres);
- mlog(0, "DONE calling dlm_purge_lockres!\n");
/* Avoid adding any scheduling latencies */
cond_resched_lock(&dlm->spinlock);