Commit 78062cb2 authored by Sunil Mushran's avatar Sunil Mushran Committed by Mark Fasheh
Browse files

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: default avatarSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
parent e0f2e3a0

fs/ocfs2/dlm/dlmdomain.c

+4 −2
Original line number Diff line number Diff line
@@ -138,9 +138,11 @@ static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm); 


void __dlm_unhash_lockres(struct dlm_lock_resource *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,

		       struct dlm_lock_resource *res)

fs/ocfs2/dlm/dlmthread.c

+2 −8
Original line number Diff line number Diff line
@@ -256,20 +256,14 @@ static void dlm_run_purge_list(struct dlm_ctxt *dlm, 
			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);