From: David Teigland <teigland@redhat.com>
Subject: [RHEL5.1 PATCH] dlm: fix user unlocking
Date: Thu, 25 Jan 2007 09:13:06 -0600
Bugzilla: 219388
Message-Id: <20070125151306.GA21980@redhat.com>
Changelog: [dlm] fix user unlocking


bz 219388

When a process holding locks exits, we clear all the locks it holds by
sending unlocks for all of the remote ones.  We aren't properly tracking
all these unlocks, so lkb's can either be leaked or we can get an oops if
there were in-flight unlocks when the process exited.

patch is in upstream gfs2 git tree


Index: linux-rhel5-quilt/fs/dlm/dlm_internal.h
===================================================================
--- linux-rhel5-quilt.orig/fs/dlm/dlm_internal.h	2007-01-24 14:42:13.000000000 -0600
+++ linux-rhel5-quilt/fs/dlm/dlm_internal.h	2007-01-24 14:57:10.000000000 -0600
@@ -524,6 +524,7 @@
 	spinlock_t		asts_spin;
 	struct list_head	locks;
 	spinlock_t		locks_spin;
+	struct list_head	unlocking;
 	wait_queue_head_t	wait;
 };
 
Index: linux-rhel5-quilt/fs/dlm/lock.c
===================================================================
--- linux-rhel5-quilt.orig/fs/dlm/lock.c	2007-01-24 14:42:12.000000000 -0600
+++ linux-rhel5-quilt/fs/dlm/lock.c	2007-01-24 14:57:10.000000000 -0600
@@ -3772,12 +3772,10 @@
 		goto out_put;
 
 	spin_lock(&ua->proc->locks_spin);
-	list_del_init(&lkb->lkb_ownqueue);
+	/* dlm_user_add_ast() may have already taken lkb off the proc list */
+	if (!list_empty(&lkb->lkb_ownqueue))
+		list_move(&lkb->lkb_ownqueue, &ua->proc->unlocking);
 	spin_unlock(&ua->proc->locks_spin);
-
-	/* this removes the reference for the proc->locks list added by
-	   dlm_user_request */
-	unhold_lkb(lkb);
  out_put:
 	dlm_put_lkb(lkb);
  out:
@@ -3817,9 +3815,8 @@
 	/* this lkb was removed from the WAITING queue */
 	if (lkb->lkb_grmode == DLM_LOCK_IV) {
 		spin_lock(&ua->proc->locks_spin);
-		list_del_init(&lkb->lkb_ownqueue);
+		list_move(&lkb->lkb_ownqueue, &ua->proc->unlocking);
 		spin_unlock(&ua->proc->locks_spin);
-		unhold_lkb(lkb);
 	}
  out_put:
 	dlm_put_lkb(lkb);
@@ -3880,11 +3877,6 @@
 	mutex_lock(&ls->ls_clear_proc_locks);
 
 	list_for_each_entry_safe(lkb, safe, &proc->locks, lkb_ownqueue) {
-		if (lkb->lkb_ast_type) {
-			list_del(&lkb->lkb_astqueue);
-			unhold_lkb(lkb);
-		}
-
 		list_del_init(&lkb->lkb_ownqueue);
 
 		if (lkb->lkb_exflags & DLM_LKF_PERSISTENT) {
@@ -3901,6 +3893,20 @@
 
 		dlm_put_lkb(lkb);
 	}
+
+	/* in-progress unlocks */
+	list_for_each_entry_safe(lkb, safe, &proc->unlocking, lkb_ownqueue) {
+		list_del_init(&lkb->lkb_ownqueue);
+		lkb->lkb_flags |= DLM_IFL_DEAD;
+		dlm_put_lkb(lkb);
+	}
+
+	list_for_each_entry_safe(lkb, safe, &proc->asts, lkb_astqueue) {
+		list_del(&lkb->lkb_astqueue);
+		dlm_put_lkb(lkb);
+	}
+
 	mutex_unlock(&ls->ls_clear_proc_locks);
 	unlock_recovery(ls);
 }
+
Index: linux-rhel5-quilt/fs/dlm/user.c
===================================================================
--- linux-rhel5-quilt.orig/fs/dlm/user.c	2007-01-24 14:42:04.000000000 -0600
+++ linux-rhel5-quilt/fs/dlm/user.c	2007-01-24 14:57:10.000000000 -0600
@@ -180,6 +180,14 @@
 	    ua->lksb.sb_status == -EAGAIN && !list_empty(&lkb->lkb_ownqueue))
 		remove_ownqueue = 1;
 
+	/* unlocks or cancels of waiting requests need to be removed from the
+	   proc's unlocking list, again there must be a better way...  */
+
+	if (ua->lksb.sb_status == -DLM_EUNLOCK ||
+	    (ua->lksb.sb_status == -DLM_ECANCEL &&
+	     lkb->lkb_grmode == DLM_LOCK_IV))
+		remove_ownqueue = 1;
+
 	/* We want to copy the lvb to userspace when the completion
 	   ast is read if the status is 0, the lock has an lvb and
 	   lvb_ops says we should.  We could probably have set_lvb_lock()
@@ -523,6 +531,7 @@
 	proc->lockspace = ls->ls_local_handle;
 	INIT_LIST_HEAD(&proc->asts);
 	INIT_LIST_HEAD(&proc->locks);
+	INIT_LIST_HEAD(&proc->unlocking);
 	spin_lock_init(&proc->asts_spin);
 	spin_lock_init(&proc->locks_spin);
 	init_waitqueue_head(&proc->wait);