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Date:      Wed, 22 Feb 2012 20:03:51 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r232003 - head/sys/ufs/ufs
Message-ID:  <201202222003.q1MK3pfl066609@svn.freebsd.org>
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Author: kib
Date: Wed Feb 22 20:03:51 2012
New Revision: 232003
URL: http://svn.freebsd.org/changeset/base/232003

Log:
  Properly lock DQREF() with dqhlock. Missed locking caused counter
  corruption.
  
  Assert that the dq reference value is sane before decrementing it.
  
  Reported and tested by:	pho
  MFC after:	1 week

Modified:
  head/sys/ufs/ufs/ufs_quota.c

Modified: head/sys/ufs/ufs/ufs_quota.c
==============================================================================
--- head/sys/ufs/ufs/ufs_quota.c	Wed Feb 22 20:01:38 2012	(r232002)
+++ head/sys/ufs/ufs/ufs_quota.c	Wed Feb 22 20:03:51 2012	(r232003)
@@ -1469,6 +1469,7 @@ dqrele(struct vnode *vp, struct dquot *d
 	if (dq == NODQUOT)
 		return;
 	DQH_LOCK();
+	KASSERT(dq->dq_cnt > 0, ("Lost dq %p reference 1", dq));
 	if (dq->dq_cnt > 1) {
 		dq->dq_cnt--;
 		DQH_UNLOCK();
@@ -1479,6 +1480,7 @@ sync:
 	(void) dqsync(vp, dq);
 
 	DQH_LOCK();
+	KASSERT(dq->dq_cnt > 0, ("Lost dq %p reference 2", dq));
 	if (--dq->dq_cnt > 0)
 	{
 		DQH_UNLOCK();
@@ -1658,6 +1660,7 @@ quotaref(vp, qrp)
 	 */
 	found = 0;
 	ip = VTOI(vp);
+	mtx_lock(&dqhlock);
 	for (i = 0; i < MAXQUOTAS; i++) {
 		if ((dq = ip->i_dquot[i]) == NODQUOT)
 			continue;
@@ -1665,6 +1668,7 @@ quotaref(vp, qrp)
 		qrp[i] = dq;
 		found++;
 	}
+	mtx_unlock(&dqhlock);
 	return (found);
 }

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