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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