ClabureDB: Classified Bug-Reports Database

   /*
    * Copyright (c) 2000-2003 Silicon Graphics, Inc.
    * All Rights Reserved.
    *
    * This program is free software; you can redistribute it and/or
    * modify it under the terms of the GNU General Public License as
    * published by the Free Software Foundation.
    *
    * This program is distributed in the hope that it would be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  #include "xfs.h"
  #include "xfs_fs.h"
  #include "xfs_bit.h"
  #include "xfs_log.h"
  #include "xfs_inum.h"
  #include "xfs_trans.h"
  #include "xfs_sb.h"
  #include "xfs_ag.h"
  #include "xfs_dir2.h"
  #include "xfs_alloc.h"
  #include "xfs_dmapi.h"
  #include "xfs_quota.h"
  #include "xfs_mount.h"
  #include "xfs_bmap_btree.h"
  #include "xfs_alloc_btree.h"
  #include "xfs_ialloc_btree.h"
  #include "xfs_dir2_sf.h"
  #include "xfs_attr_sf.h"
  #include "xfs_dinode.h"
  #include "xfs_inode.h"
  #include "xfs_btree.h"
  #include "xfs_ialloc.h"
  #include "xfs_bmap.h"
  #include "xfs_rtalloc.h"
  #include "xfs_error.h"
  #include "xfs_itable.h"
  #include "xfs_rw.h"
  #include "xfs_acl.h"
  #include "xfs_attr.h"
  #include "xfs_buf_item.h"
  #include "xfs_trans_space.h"
  #include "xfs_trans_priv.h"
  #include "xfs_qm.h"
  
  
  /*
     LOCK ORDER
  
     inode lock                    (ilock)
     dquot hash-chain lock    (hashlock)
     xqm dquot freelist lock  (freelistlock
     mount's dquot list lock  (mplistlock)
     user dquot lock - lock ordering among dquots is based on the uid or gid
     group dquot lock - similar to udquots. Between the two dquots, the udquot
                        has to be locked first.
     pin lock - the dquot lock must be held to take this lock.
     flush lock - ditto.
  */
  
  STATIC void                xfs_qm_dqflush_done(xfs_buf_t *, xfs_dq_logitem_t *);
  
  #ifdef DEBUG
  xfs_buftarg_t *xfs_dqerror_target;
  int xfs_do_dqerror;
  int xfs_dqreq_num;
  int xfs_dqerror_mod = 33;
  #endif
  
  /*
   * Allocate and initialize a dquot. We don't always allocate fresh memory;
   * we try to reclaim a free dquot if the number of incore dquots are above
   * a threshold.
   * The only field inside the core that gets initialized at this point
   * is the d_id field. The idea is to fill in the entire q_core
   * when we read in the on disk dquot.
   */
  STATIC xfs_dquot_t *
  xfs_qm_dqinit(
          xfs_mount_t  *mp,
          xfs_dqid_t   id,
          uint             type)
  {
          xfs_dquot_t        *dqp;
          boolean_t        brandnewdquot;
  
          brandnewdquot = xfs_qm_dqalloc_incore(&dqp);
          dqp->dq_flags = type;
          dqp->q_core.d_id = cpu_to_be32(id);
          dqp->q_mount = mp;
  
          /*
           * No need to re-initialize these if this is a reclaimed dquot.
          */
         if (brandnewdquot) {
                 dqp->dq_flnext = dqp->dq_flprev = dqp;
                 mutex_init(&dqp->q_qlock);
                 sv_init(&dqp->q_pinwait, SV_DEFAULT, "pdq");
 
                 /*
                  * Because we want to use a counting completion, complete
                  * the flush completion once to allow a single access to
                  * the flush completion without blocking.
                  */
                 init_completion(&dqp->q_flush);
                 complete(&dqp->q_flush);
 
 #ifdef XFS_DQUOT_TRACE
                 dqp->q_trace = ktrace_alloc(DQUOT_TRACE_SIZE, KM_NOFS);
                 xfs_dqtrace_entry(dqp, "DQINIT");
 #endif
         } else {
                 /*
                  * Only the q_core portion was zeroed in dqreclaim_one().
                  * So, we need to reset others.
                  */
                  dqp->q_nrefs = 0;
                  dqp->q_blkno = 0;
                  dqp->MPL_NEXT = dqp->HL_NEXT = NULL;
                  dqp->HL_PREVP = dqp->MPL_PREVP = NULL;
                  dqp->q_bufoffset = 0;
                  dqp->q_fileoffset = 0;
                  dqp->q_transp = NULL;
                  dqp->q_gdquot = NULL;
                  dqp->q_res_bcount = 0;
                  dqp->q_res_icount = 0;
                  dqp->q_res_rtbcount = 0;
                  dqp->q_pincount = 0;
                  dqp->q_hash = NULL;
                  ASSERT(dqp->dq_flnext == dqp->dq_flprev);
 
 #ifdef XFS_DQUOT_TRACE
                  ASSERT(dqp->q_trace);
                  xfs_dqtrace_entry(dqp, "DQRECLAIMED_INIT");
 #endif
          }
 
         /*
          * log item gets initialized later
          */
         return (dqp);
 }
 
 /*
  * This is called to free all the memory associated with a dquot
  */
 void
 xfs_qm_dqdestroy(
         xfs_dquot_t        *dqp)
 {
         ASSERT(! XFS_DQ_IS_ON_FREELIST(dqp));
 
         mutex_destroy(&dqp->q_qlock);
         sv_destroy(&dqp->q_pinwait);
 
 #ifdef XFS_DQUOT_TRACE
         if (dqp->q_trace)
              ktrace_free(dqp->q_trace);
         dqp->q_trace = NULL;
 #endif
         kmem_zone_free(xfs_Gqm->qm_dqzone, dqp);
         atomic_dec(&xfs_Gqm->qm_totaldquots);
 }
 
 /*
  * This is what a 'fresh' dquot inside a dquot chunk looks like on disk.
  */
 STATIC void
 xfs_qm_dqinit_core(
         xfs_dqid_t        id,
         uint                type,
         xfs_dqblk_t        *d)
 {
         /*
          * Caller has zero'd the entire dquot 'chunk' already.
          */
         d->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);
         d->dd_diskdq.d_version = XFS_DQUOT_VERSION;
         d->dd_diskdq.d_id = cpu_to_be32(id);
         d->dd_diskdq.d_flags = type;
 }
 
 
 #ifdef XFS_DQUOT_TRACE
 /*
  * Dquot tracing for debugging.
  */
 /* ARGSUSED */
 void
 __xfs_dqtrace_entry(
         xfs_dquot_t        *dqp,
         char                *func,
         void                *retaddr,
         xfs_inode_t        *ip)
 {
         xfs_dquot_t        *udqp = NULL;
         xfs_ino_t        ino = 0;
 
         ASSERT(dqp->q_trace);
         if (ip) {
                 ino = ip->i_ino;
                 udqp = ip->i_udquot;
         }
         ktrace_enter(dqp->q_trace,
                      (void *)(__psint_t)DQUOT_KTRACE_ENTRY,
                      (void *)func,
                      (void *)(__psint_t)dqp->q_nrefs,
                      (void *)(__psint_t)dqp->dq_flags,
                      (void *)(__psint_t)dqp->q_res_bcount,
                      (void *)(__psint_t)be64_to_cpu(dqp->q_core.d_bcount),
                      (void *)(__psint_t)be64_to_cpu(dqp->q_core.d_icount),
                      (void *)(__psint_t)be64_to_cpu(dqp->q_core.d_blk_hardlimit),
                      (void *)(__psint_t)be64_to_cpu(dqp->q_core.d_blk_softlimit),
                      (void *)(__psint_t)be64_to_cpu(dqp->q_core.d_ino_hardlimit),
                      (void *)(__psint_t)be64_to_cpu(dqp->q_core.d_ino_softlimit),
                      (void *)(__psint_t)be32_to_cpu(dqp->q_core.d_id),
                      (void *)(__psint_t)current_pid(),
                      (void *)(__psint_t)ino,
                      (void *)(__psint_t)retaddr,
                      (void *)(__psint_t)udqp);
         return;
 }
 #endif
 
 
 /*
  * If default limits are in force, push them into the dquot now.
  * We overwrite the dquot limits only if they are zero and this
  * is not the root dquot.
  */
 void
 xfs_qm_adjust_dqlimits(
         xfs_mount_t                *mp,
         xfs_disk_dquot_t        *d)
 {
         xfs_quotainfo_t                *q = mp->m_quotainfo;
 
         ASSERT(d->d_id);
 
         if (q->qi_bsoftlimit && !d->d_blk_softlimit)
                 d->d_blk_softlimit = cpu_to_be64(q->qi_bsoftlimit);
         if (q->qi_bhardlimit && !d->d_blk_hardlimit)
                 d->d_blk_hardlimit = cpu_to_be64(q->qi_bhardlimit);
         if (q->qi_isoftlimit && !d->d_ino_softlimit)
                 d->d_ino_softlimit = cpu_to_be64(q->qi_isoftlimit);
         if (q->qi_ihardlimit && !d->d_ino_hardlimit)
                 d->d_ino_hardlimit = cpu_to_be64(q->qi_ihardlimit);
         if (q->qi_rtbsoftlimit && !d->d_rtb_softlimit)
                 d->d_rtb_softlimit = cpu_to_be64(q->qi_rtbsoftlimit);
         if (q->qi_rtbhardlimit && !d->d_rtb_hardlimit)
                 d->d_rtb_hardlimit = cpu_to_be64(q->qi_rtbhardlimit);
 }
 
 /*
  * Check the limits and timers of a dquot and start or reset timers
  * if necessary.
  * This gets called even when quota enforcement is OFF, which makes our
  * life a little less complicated. (We just don't reject any quota
  * reservations in that case, when enforcement is off).
  * We also return 0 as the values of the timers in Q_GETQUOTA calls, when
  * enforcement's off.
  * In contrast, warnings are a little different in that they don't
  * 'automatically' get started when limits get exceeded.  They do
  * get reset to zero, however, when we find the count to be under
  * the soft limit (they are only ever set non-zero via userspace).
  */
 void
 xfs_qm_adjust_dqtimers(
         xfs_mount_t                *mp,
         xfs_disk_dquot_t        *d)
 {
         ASSERT(d->d_id);
 
 #ifdef QUOTADEBUG
         if (d->d_blk_hardlimit)
                 ASSERT(be64_to_cpu(d->d_blk_softlimit) <=
                        be64_to_cpu(d->d_blk_hardlimit));
         if (d->d_ino_hardlimit)
                 ASSERT(be64_to_cpu(d->d_ino_softlimit) <=
                        be64_to_cpu(d->d_ino_hardlimit));
         if (d->d_rtb_hardlimit)
                 ASSERT(be64_to_cpu(d->d_rtb_softlimit) <=
                        be64_to_cpu(d->d_rtb_hardlimit));
 #endif
         if (!d->d_btimer) {
                 if ((d->d_blk_softlimit &&
                      (be64_to_cpu(d->d_bcount) >=
                       be64_to_cpu(d->d_blk_softlimit))) ||
                     (d->d_blk_hardlimit &&
                      (be64_to_cpu(d->d_bcount) >=
                       be64_to_cpu(d->d_blk_hardlimit)))) {
                         d->d_btimer = cpu_to_be32(get_seconds() +
                                         XFS_QI_BTIMELIMIT(mp));
                 } else {
                         d->d_bwarns = 0;
                 }
         } else {
                 if ((!d->d_blk_softlimit ||
                      (be64_to_cpu(d->d_bcount) <
                       be64_to_cpu(d->d_blk_softlimit))) &&
                     (!d->d_blk_hardlimit ||
                     (be64_to_cpu(d->d_bcount) <
                      be64_to_cpu(d->d_blk_hardlimit)))) {
                         d->d_btimer = 0;
                 }
         }
 
         if (!d->d_itimer) {
                 if ((d->d_ino_softlimit &&
                      (be64_to_cpu(d->d_icount) >=
                       be64_to_cpu(d->d_ino_softlimit))) ||
                     (d->d_ino_hardlimit &&
                      (be64_to_cpu(d->d_icount) >=
                       be64_to_cpu(d->d_ino_hardlimit)))) {
                         d->d_itimer = cpu_to_be32(get_seconds() +
                                         XFS_QI_ITIMELIMIT(mp));
                 } else {
                         d->d_iwarns = 0;
                 }
         } else {
                 if ((!d->d_ino_softlimit ||
                      (be64_to_cpu(d->d_icount) <
                       be64_to_cpu(d->d_ino_softlimit)))  &&
                     (!d->d_ino_hardlimit ||
                      (be64_to_cpu(d->d_icount) <
                       be64_to_cpu(d->d_ino_hardlimit)))) {
                         d->d_itimer = 0;
                 }
         }
 
         if (!d->d_rtbtimer) {
                 if ((d->d_rtb_softlimit &&
                      (be64_to_cpu(d->d_rtbcount) >=
                       be64_to_cpu(d->d_rtb_softlimit))) ||
                     (d->d_rtb_hardlimit &&
                      (be64_to_cpu(d->d_rtbcount) >=
                       be64_to_cpu(d->d_rtb_hardlimit)))) {
                         d->d_rtbtimer = cpu_to_be32(get_seconds() +
                                         XFS_QI_RTBTIMELIMIT(mp));
                 } else {
                         d->d_rtbwarns = 0;
                 }
         } else {
                 if ((!d->d_rtb_softlimit ||
                      (be64_to_cpu(d->d_rtbcount) <
                       be64_to_cpu(d->d_rtb_softlimit))) &&
                     (!d->d_rtb_hardlimit ||
                      (be64_to_cpu(d->d_rtbcount) <
                       be64_to_cpu(d->d_rtb_hardlimit)))) {
                         d->d_rtbtimer = 0;
                 }
         }
 }
 
 /*
  * initialize a buffer full of dquots and log the whole thing
  */
 STATIC void
 xfs_qm_init_dquot_blk(
         xfs_trans_t        *tp,
         xfs_mount_t        *mp,
         xfs_dqid_t        id,
         uint                type,
         xfs_buf_t        *bp)
 {
         xfs_dqblk_t        *d;
         int                curid, i;
 
         ASSERT(tp);
         ASSERT(XFS_BUF_ISBUSY(bp));
         ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
 
         d = (xfs_dqblk_t *)XFS_BUF_PTR(bp);
 
         /*
          * ID of the first dquot in the block - id's are zero based.
          */
         curid = id - (id % XFS_QM_DQPERBLK(mp));
         ASSERT(curid >= 0);
         memset(d, 0, BBTOB(XFS_QI_DQCHUNKLEN(mp)));
         for (i = 0; i < XFS_QM_DQPERBLK(mp); i++, d++, curid++)
                 xfs_qm_dqinit_core(curid, type, d);
         xfs_trans_dquot_buf(tp, bp,
                             (type & XFS_DQ_USER ? XFS_BLI_UDQUOT_BUF :
                             ((type & XFS_DQ_PROJ) ? XFS_BLI_PDQUOT_BUF :
                              XFS_BLI_GDQUOT_BUF)));
         xfs_trans_log_buf(tp, bp, 0, BBTOB(XFS_QI_DQCHUNKLEN(mp)) - 1);
 }
 
 
 
 /*
  * Allocate a block and fill it with dquots.
  * This is called when the bmapi finds a hole.
  */
 STATIC int
 xfs_qm_dqalloc(
         xfs_trans_t        **tpp,
         xfs_mount_t        *mp,
         xfs_dquot_t        *dqp,
         xfs_inode_t        *quotip,
         xfs_fileoff_t        offset_fsb,
         xfs_buf_t        **O_bpp)
 {
         xfs_fsblock_t        firstblock;
         xfs_bmap_free_t flist;
         xfs_bmbt_irec_t map;
         int                nmaps, error, committed;
         xfs_buf_t        *bp;
         xfs_trans_t        *tp = *tpp;
 
         ASSERT(tp != NULL);
         xfs_dqtrace_entry(dqp, "DQALLOC");
 
         /*
          * Initialize the bmap freelist prior to calling bmapi code.
          */
         XFS_BMAP_INIT(&flist, &firstblock);
         xfs_ilock(quotip, XFS_ILOCK_EXCL);
         /*
          * Return if this type of quotas is turned off while we didn't
          * have an inode lock
          */
         if (XFS_IS_THIS_QUOTA_OFF(dqp)) {
                 xfs_iunlock(quotip, XFS_ILOCK_EXCL);
                 return (ESRCH);
         }
 
         /*
          * xfs_trans_commit normally decrements the vnode ref count
          * when it unlocks the inode. Since we want to keep the quota
          * inode around, we bump the vnode ref count now.
          */
         IHOLD(quotip);
 
         xfs_trans_ijoin(tp, quotip, XFS_ILOCK_EXCL);
         nmaps = 1;
         if ((error = xfs_bmapi(tp, quotip,
                               offset_fsb, XFS_DQUOT_CLUSTER_SIZE_FSB,
                               XFS_BMAPI_METADATA | XFS_BMAPI_WRITE,
                               &firstblock,
                               XFS_QM_DQALLOC_SPACE_RES(mp),
                               &map, &nmaps, &flist, NULL))) {
                 goto error0;
         }
         ASSERT(map.br_blockcount == XFS_DQUOT_CLUSTER_SIZE_FSB);
         ASSERT(nmaps == 1);
         ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
                (map.br_startblock != HOLESTARTBLOCK));
 
         /*
          * Keep track of the blkno to save a lookup later
          */
         dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
 
         /* now we can just get the buffer (there's nothing to read yet) */
         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
                                dqp->q_blkno,
                                XFS_QI_DQCHUNKLEN(mp),
                                0);
         if (!bp || (error = XFS_BUF_GETERROR(bp)))
                 goto error1;
         /*
          * Make a chunk of dquots out of this buffer and log
          * the entire thing.
          */
         xfs_qm_init_dquot_blk(tp, mp, be32_to_cpu(dqp->q_core.d_id),
                               dqp->dq_flags & XFS_DQ_ALLTYPES, bp);
 
         /*
          * xfs_bmap_finish() may commit the current transaction and
          * start a second transaction if the freelist is not empty.
          *
          * Since we still want to modify this buffer, we need to
          * ensure that the buffer is not released on commit of
          * the first transaction and ensure the buffer is added to the
          * second transaction.
          *
          * If there is only one transaction then don't stop the buffer
          * from being released when it commits later on.
          */
 
         xfs_trans_bhold(tp, bp);
 
         if ((error = xfs_bmap_finish(tpp, &flist, &committed))) {
                 goto error1;
         }
 
         if (committed) {
                 tp = *tpp;
                 xfs_trans_bjoin(tp, bp);
         } else {
                 xfs_trans_bhold_release(tp, bp);
         }
 
         *O_bpp = bp;
         return 0;
 
       error1:
         xfs_bmap_cancel(&flist);
       error0:
         xfs_iunlock(quotip, XFS_ILOCK_EXCL);
 
         return (error);
 }
 
 /*
  * Maps a dquot to the buffer containing its on-disk version.
  * This returns a ptr to the buffer containing the on-disk dquot
  * in the bpp param, and a ptr to the on-disk dquot within that buffer
  */
 STATIC int
 xfs_qm_dqtobp(
         xfs_trans_t                **tpp,
         xfs_dquot_t                *dqp,
         xfs_disk_dquot_t        **O_ddpp,
         xfs_buf_t                **O_bpp,
         uint                        flags)
 {
         xfs_bmbt_irec_t map;
         int                nmaps, error;
         xfs_buf_t        *bp;
         xfs_inode_t        *quotip;
         xfs_mount_t        *mp;
         xfs_disk_dquot_t *ddq;
         xfs_dqid_t        id;
         boolean_t        newdquot;
         xfs_trans_t        *tp = (tpp ? *tpp : NULL);
 
         mp = dqp->q_mount;
         id = be32_to_cpu(dqp->q_core.d_id);
         nmaps = 1;
         newdquot = B_FALSE;
 
         /*
          * If we don't know where the dquot lives, find out.
          */
         if (dqp->q_blkno == (xfs_daddr_t) 0) {
                 /* We use the id as an index */
                 dqp->q_fileoffset = (xfs_fileoff_t)id / XFS_QM_DQPERBLK(mp);
                 nmaps = 1;
                 quotip = XFS_DQ_TO_QIP(dqp);
                 xfs_ilock(quotip, XFS_ILOCK_SHARED);
                 /*
                  * Return if this type of quotas is turned off while we didn't
                  * have an inode lock
                  */
                 if (XFS_IS_THIS_QUOTA_OFF(dqp)) {
                         xfs_iunlock(quotip, XFS_ILOCK_SHARED);
                         return (ESRCH);
                 }
                 /*
                  * Find the block map; no allocations yet
                  */
                 error = xfs_bmapi(NULL, quotip, dqp->q_fileoffset,
                                   XFS_DQUOT_CLUSTER_SIZE_FSB,
                                   XFS_BMAPI_METADATA,
                                   NULL, 0, &map, &nmaps, NULL, NULL);
 
                 xfs_iunlock(quotip, XFS_ILOCK_SHARED);
                 if (error)
                         return (error);
                 ASSERT(nmaps == 1);
                 ASSERT(map.br_blockcount == 1);
 
                 /*
                  * offset of dquot in the (fixed sized) dquot chunk.
                  */
                 dqp->q_bufoffset = (id % XFS_QM_DQPERBLK(mp)) *
                         sizeof(xfs_dqblk_t);
                 if (map.br_startblock == HOLESTARTBLOCK) {
                         /*
                          * We don't allocate unless we're asked to
                          */
                         if (!(flags & XFS_QMOPT_DQALLOC))
                                 return (ENOENT);
 
                         ASSERT(tp);
                         if ((error = xfs_qm_dqalloc(tpp, mp, dqp, quotip,
                                                 dqp->q_fileoffset, &bp)))
                                 return (error);
                         tp = *tpp;
                         newdquot = B_TRUE;
                 } else {
                         /*
                          * store the blkno etc so that we don't have to do the
                          * mapping all the time
                          */
                         dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
                 }
         }
         ASSERT(dqp->q_blkno != DELAYSTARTBLOCK);
         ASSERT(dqp->q_blkno != HOLESTARTBLOCK);
 
         /*
          * Read in the buffer, unless we've just done the allocation
          * (in which case we already have the buf).
          */
         if (! newdquot) {
                 xfs_dqtrace_entry(dqp, "DQTOBP READBUF");
                 if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
                                                dqp->q_blkno,
                                                XFS_QI_DQCHUNKLEN(mp),
                                                0, &bp))) {
                         return (error);
                 }
                 if (error || !bp)
                         return XFS_ERROR(error);
         }
         ASSERT(XFS_BUF_ISBUSY(bp));
         ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
 
         /*
          * calculate the location of the dquot inside the buffer.
          */
         ddq = (xfs_disk_dquot_t *)((char *)XFS_BUF_PTR(bp) + dqp->q_bufoffset);
 
         /*
          * A simple sanity check in case we got a corrupted dquot...
          */
         if (xfs_qm_dqcheck(ddq, id, dqp->dq_flags & XFS_DQ_ALLTYPES,
                            flags & (XFS_QMOPT_DQREPAIR|XFS_QMOPT_DOWARN),
                            "dqtobp")) {
                 if (!(flags & XFS_QMOPT_DQREPAIR)) {
                         xfs_trans_brelse(tp, bp);
                         return XFS_ERROR(EIO);
                 }
                 XFS_BUF_BUSY(bp); /* We dirtied this */
         }
 
         *O_bpp = bp;
         *O_ddpp = ddq;
 
         return (0);
 }
 
 
 /*
  * Read in the ondisk dquot using dqtobp() then copy it to an incore version,
  * and release the buffer immediately.
  *
  */
 /* ARGSUSED */
 STATIC int
 xfs_qm_dqread(
         xfs_trans_t        **tpp,
         xfs_dqid_t        id,
         xfs_dquot_t        *dqp,        /* dquot to get filled in */
         uint                flags)
 {
         xfs_disk_dquot_t *ddqp;
         xfs_buf_t         *bp;
         int                 error;
         xfs_trans_t         *tp;
 
         ASSERT(tpp);
 
         /*
          * get a pointer to the on-disk dquot and the buffer containing it
          * dqp already knows its own type (GROUP/USER).
          */
         xfs_dqtrace_entry(dqp, "DQREAD");
         if ((error = xfs_qm_dqtobp(tpp, dqp, &ddqp, &bp, flags))) {
                 return (error);
         }
         tp = *tpp;
 
         /* copy everything from disk dquot to the incore dquot */
         memcpy(&dqp->q_core, ddqp, sizeof(xfs_disk_dquot_t));
         ASSERT(be32_to_cpu(dqp->q_core.d_id) == id);
         xfs_qm_dquot_logitem_init(dqp);
 
         /*
          * Reservation counters are defined as reservation plus current usage
          * to avoid having to add everytime.
          */
         dqp->q_res_bcount = be64_to_cpu(ddqp->d_bcount);
         dqp->q_res_icount = be64_to_cpu(ddqp->d_icount);
         dqp->q_res_rtbcount = be64_to_cpu(ddqp->d_rtbcount);
 
         /* Mark the buf so that this will stay incore a little longer */
         XFS_BUF_SET_VTYPE_REF(bp, B_FS_DQUOT, XFS_DQUOT_REF);
 
         /*
          * We got the buffer with a xfs_trans_read_buf() (in dqtobp())
          * So we need to release with xfs_trans_brelse().
          * The strategy here is identical to that of inodes; we lock
          * the dquot in xfs_qm_dqget() before making it accessible to
          * others. This is because dquots, like inodes, need a good level of
          * concurrency, and we don't want to take locks on the entire buffers
          * for dquot accesses.
          * Note also that the dquot buffer may even be dirty at this point, if
          * this particular dquot was repaired. We still aren't afraid to
          * brelse it because we have the changes incore.
          */
         ASSERT(XFS_BUF_ISBUSY(bp));
         ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
         xfs_trans_brelse(tp, bp);
 
         return (error);
 }
 
 
 /*
  * allocate an incore dquot from the kernel heap,
  * and fill its core with quota information kept on disk.
  * If XFS_QMOPT_DQALLOC is set, it'll allocate a dquot on disk
  * if it wasn't already allocated.
  */
 STATIC int
 xfs_qm_idtodq(
         xfs_mount_t        *mp,
         xfs_dqid_t        id,         /* gid or uid, depending on type */
         uint                type,         /* UDQUOT or GDQUOT */
         uint                flags,         /* DQALLOC, DQREPAIR */
         xfs_dquot_t        **O_dqpp)/* OUT : incore dquot, not locked */
 {
         xfs_dquot_t        *dqp;
         int                error;
         xfs_trans_t        *tp;
         int                cancelflags=0;
 
         dqp = xfs_qm_dqinit(mp, id, type);
         tp = NULL;
         if (flags & XFS_QMOPT_DQALLOC) {
                 tp = xfs_trans_alloc(mp, XFS_TRANS_QM_DQALLOC);
                 if ((error = xfs_trans_reserve(tp,
                                        XFS_QM_DQALLOC_SPACE_RES(mp),
                                        XFS_WRITE_LOG_RES(mp) +
                                               BBTOB(XFS_QI_DQCHUNKLEN(mp)) - 1 +
                                               128,
                                        0,
                                        XFS_TRANS_PERM_LOG_RES,
                                        XFS_WRITE_LOG_COUNT))) {
                         cancelflags = 0;
                         goto error0;
                 }
                 cancelflags = XFS_TRANS_RELEASE_LOG_RES;
         }
 
         /*
          * Read it from disk; xfs_dqread() takes care of
          * all the necessary initialization of dquot's fields (locks, etc)
          */
         if ((error = xfs_qm_dqread(&tp, id, dqp, flags))) {
                 /*
                  * This can happen if quotas got turned off (ESRCH),
                  * or if the dquot didn't exist on disk and we ask to
                  * allocate (ENOENT).
                  */
                 xfs_dqtrace_entry(dqp, "DQREAD FAIL");
                 cancelflags |= XFS_TRANS_ABORT;
                 goto error0;
         }
         if (tp) {
                 if ((error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES)))
                         goto error1;
         }
 
         *O_dqpp = dqp;
         return (0);
 
  error0:
         ASSERT(error);
         if (tp)
                 xfs_trans_cancel(tp, cancelflags);
  error1:
         xfs_qm_dqdestroy(dqp);
         *O_dqpp = NULL;
         return (error);
 }
 
 /*
  * Lookup a dquot in the incore dquot hashtable. We keep two separate
  * hashtables for user and group dquots; and, these are global tables
  * inside the XQM, not per-filesystem tables.
  * The hash chain must be locked by caller, and it is left locked
  * on return. Returning dquot is locked.
  */
 STATIC int
 xfs_qm_dqlookup(
         xfs_mount_t                *mp,
         xfs_dqid_t                id,
         xfs_dqhash_t                *qh,
         xfs_dquot_t                **O_dqpp)
 {
         xfs_dquot_t                *dqp;
         uint                        flist_locked;
         xfs_dquot_t                *d;
 
         ASSERT(XFS_DQ_IS_HASH_LOCKED(qh));
 
         flist_locked = B_FALSE;
 
         /*
          * Traverse the hashchain looking for a match
          */
         for (dqp = qh->qh_next; dqp != NULL; dqp = dqp->HL_NEXT) {
                 /*
                  * We already have the hashlock. We don't need the
                  * dqlock to look at the id field of the dquot, since the
                  * id can't be modified without the hashlock anyway.
                  */
                 if (be32_to_cpu(dqp->q_core.d_id) == id && dqp->q_mount == mp) {
                         xfs_dqtrace_entry(dqp, "DQFOUND BY LOOKUP");
                         /*
                          * All in core dquots must be on the dqlist of mp
                          */
                         ASSERT(dqp->MPL_PREVP != NULL);
 
                         xfs_dqlock(dqp);
                         if (dqp->q_nrefs == 0) {
                                 ASSERT (XFS_DQ_IS_ON_FREELIST(dqp));
                                 if (! xfs_qm_freelist_lock_nowait(xfs_Gqm)) {
                                         xfs_dqtrace_entry(dqp, "DQLOOKUP: WANT");
 
                                         /*
                                          * We may have raced with dqreclaim_one()
                                          * (and lost). So, flag that we don't
                                          * want the dquot to be reclaimed.
                                          */
                                         dqp->dq_flags |= XFS_DQ_WANT;
                                         xfs_dqunlock(dqp);
                                         xfs_qm_freelist_lock(xfs_Gqm);
                                         xfs_dqlock(dqp);
                                         dqp->dq_flags &= ~(XFS_DQ_WANT);
                                 }
                                 flist_locked = B_TRUE;
                         }
 
                         /*
                          * id couldn't have changed; we had the hashlock all
                          * along
                          */
                         ASSERT(be32_to_cpu(dqp->q_core.d_id) == id);
 
                         if (flist_locked) {
                                 if (dqp->q_nrefs != 0) {
                                         xfs_qm_freelist_unlock(xfs_Gqm);
                                         flist_locked = B_FALSE;
                                 } else {
                                         /*
                                          * take it off the freelist
                                          */
                                         xfs_dqtrace_entry(dqp,
                                                         "DQLOOKUP: TAKEOFF FL");
                                         XQM_FREELIST_REMOVE(dqp);
                                         /* xfs_qm_freelist_print(&(xfs_Gqm->
                                                         qm_dqfreelist),
                                                         "after removal"); */
                                 }
                         }
 
                         /*
                          * grab a reference
                          */
                         XFS_DQHOLD(dqp);
 
                         if (flist_locked)
                                 xfs_qm_freelist_unlock(xfs_Gqm);
                         /*
                          * move the dquot to the front of the hashchain
                          */
                         ASSERT(XFS_DQ_IS_HASH_LOCKED(qh));
                         if (dqp->HL_PREVP != &qh->qh_next) {
                                 xfs_dqtrace_entry(dqp,
                                                   "DQLOOKUP: HASH MOVETOFRONT");
                                 if ((d = dqp->HL_NEXT))
                                         d->HL_PREVP = dqp->HL_PREVP;
                                 *(dqp->HL_PREVP) = d;
                                 d = qh->qh_next;
                                 d->HL_PREVP = &dqp->HL_NEXT;
                                 dqp->HL_NEXT = d;
                                 dqp->HL_PREVP = &qh->qh_next;
                                 qh->qh_next = dqp;
                         }
                         xfs_dqtrace_entry(dqp, "LOOKUP END");
                         *O_dqpp = dqp;
                         ASSERT(XFS_DQ_IS_HASH_LOCKED(qh));
                         return (0);
                 }
         }
 
         *O_dqpp = NULL;
         ASSERT(XFS_DQ_IS_HASH_LOCKED(qh));
         return (1);
 }
 
 /*
  * Given the file system, inode OR id, and type (UDQUOT/GDQUOT), return a
  * a locked dquot, doing an allocation (if requested) as needed.
  * When both an inode and an id are given, the inode's id takes precedence.
  * That is, if the id changes while we don't hold the ilock inside this
  * function, the new dquot is returned, not necessarily the one requested
  * in the id argument.
  */
 int
 xfs_qm_dqget(
         xfs_mount_t        *mp,
         xfs_inode_t        *ip,          /* locked inode (optional) */
         xfs_dqid_t        id,          /* uid/projid/gid depending on type */
         uint                type,          /* XFS_DQ_USER/XFS_DQ_PROJ/XFS_DQ_GROUP */
         uint                flags,          /* DQALLOC, DQSUSER, DQREPAIR, DOWARN */
         xfs_dquot_t        **O_dqpp) /* OUT : locked incore dquot */
 {
         xfs_dquot_t        *dqp;
         xfs_dqhash_t        *h;
         uint                version;
         int                error;
 
         ASSERT(XFS_IS_QUOTA_RUNNING(mp));
         if ((! XFS_IS_UQUOTA_ON(mp) && type == XFS_DQ_USER) ||
             (! XFS_IS_PQUOTA_ON(mp) && type == XFS_DQ_PROJ) ||
             (! XFS_IS_GQUOTA_ON(mp) && type == XFS_DQ_GROUP)) {
                 return (ESRCH);
         }
         h = XFS_DQ_HASH(mp, id, type);
 
 #ifdef DEBUG
         if (xfs_do_dqerror) {
                 if ((xfs_dqerror_target == mp->m_ddev_targp) &&
                     (xfs_dqreq_num++ % xfs_dqerror_mod) == 0) {
                         cmn_err(CE_DEBUG, "Returning error in dqget");
                         return (EIO);
                 }
         }
 #endif
 
  again:
 
 #ifdef DEBUG
         ASSERT(type == XFS_DQ_USER ||
                type == XFS_DQ_PROJ ||
                type == XFS_DQ_GROUP);
         if (ip) {
                 ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
                 if (type == XFS_DQ_USER)
                         ASSERT(ip->i_udquot == NULL);
                 else
                         ASSERT(ip->i_gdquot == NULL);
         }
 #endif
         XFS_DQ_HASH_LOCK(h);
 
         /*
          * Look in the cache (hashtable).
          * The chain is kept locked during lookup.
          */
         if (xfs_qm_dqlookup(mp, id, h, O_dqpp) == 0) {
                 XQM_STATS_INC(xqmstats.xs_qm_dqcachehits);
                 /*
                  * The dquot was found, moved to the front of the chain,
                  * taken off the freelist if it was on it, and locked
                  * at this point. Just unlock the hashchain and return.
                  */
                 ASSERT(*O_dqpp);
                 ASSERT(XFS_DQ_IS_LOCKED(*O_dqpp));
                 XFS_DQ_HASH_UNLOCK(h);
                 xfs_dqtrace_entry(*O_dqpp, "DQGET DONE (FROM CACHE)");
                 return (0);        /* success */
         }
         XQM_STATS_INC(xqmstats.xs_qm_dqcachemisses);
 
         /*
          * Dquot cache miss. We don't want to keep the inode lock across
          * a (potential) disk read. Also we don't want to deal with the lock
          * ordering between quotainode and this inode. OTOH, dropping the inode
          * lock here means dealing with a chown that can happen before
          * we re-acquire the lock.
          */
         if (ip)
                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
         /*
          * Save the hashchain version stamp, and unlock the chain, so that
          * we don't keep the lock across a disk read
          */
         version = h->qh_version;
         XFS_DQ_HASH_UNLOCK(h);
 
         /*
          * Allocate the dquot on the kernel heap, and read the ondisk
          * portion off the disk. Also, do all the necessary initialization
          * This can return ENOENT if dquot didn't exist on disk and we didn't
          * ask it to allocate; ESRCH if quotas got turned off suddenly.
          */
         if ((error = xfs_qm_idtodq(mp, id, type,
                                   flags & (XFS_QMOPT_DQALLOC|XFS_QMOPT_DQREPAIR|
                                            XFS_QMOPT_DOWARN),
                                   &dqp))) {
                 if (ip)
                         xfs_ilock(ip, XFS_ILOCK_EXCL);
                 return (error);
         }

        /*
         * See if this is mount code calling to look at the overall quota limits
         * which are stored in the id == 0 user or group's dquot.
         * Since we may not have done a quotacheck by this point, just return
         * the dquot without attaching it to any hashtables, lists, etc, or even
         * taking a reference.
         * The caller must dqdestroy this once done.
         */
        if (flags & XFS_QMOPT_DQSUSER) {
                ASSERT(id == 0);
                ASSERT(! ip);
                goto dqret;
        }

        /*
         * Dquot lock comes after hashlock in the lock ordering
         */
        if (ip) {
                xfs_ilock(ip, XFS_ILOCK_EXCL);
                if (! XFS_IS_DQTYPE_ON(mp, type)) {
                        /* inode stays locked on return */
                        xfs_qm_dqdestroy(dqp);
                        return XFS_ERROR(ESRCH);
                }
                /*
                 * A dquot could be attached to this inode by now, since
                 * we had dropped the ilock.
                 */
                if (type == XFS_DQ_USER) {
                        if (ip->i_udquot) {
                                xfs_qm_dqdestroy(dqp);
                                dqp = ip->i_udquot;
                                xfs_dqlock(dqp);
                                goto dqret;
                        }
                } else {
                        if (ip->i_gdquot) {
                                xfs_qm_dqdestroy(dqp);
                                dqp = ip->i_gdquot;
                                xfs_dqlock(dqp);
                                goto dqret;
                        }
                }
        }

        /*
         * Hashlock comes after ilock in lock order
         */
        XFS_DQ_HASH_LOCK(h);
        if (version != h->qh_version) {
                xfs_dquot_t *tmpdqp;
                /*
                 * Now, see if somebody else put the dquot in the
                 * hashtable before us. This can happen because we didn't
                 * keep the hashchain lock. We don't have to worry about
                 * lock order between the two dquots here since dqp isn't
                 * on any findable lists yet.
                 */
                if (xfs_qm_dqlookup(mp, id, h, &tmpdqp) == 0) {
                        /*
                         * Duplicate found. Just throw away the new dquot
                         * and start over.
                         */
                        xfs_qm_dqput(tmpdqp);
                        XFS_DQ_HASH_UNLOCK(h);
                        xfs_qm_dqdestroy(dqp);
                        XQM_STATS_INC(xqmstats.xs_qm_dquot_dups);
                        goto again;
                }
        }

        /*
         * Put the dquot at the beginning of the hash-chain and mp's list
         * LOCK ORDER: hashlock, freelistlock, mplistlock, udqlock, gdqlock ..
         */
        ASSERT(XFS_DQ_IS_HASH_LOCKED(h));
        dqp->q_hash = h;
        XQM_HASHLIST_INSERT(h, dqp);

        /*
         * Attach this dquot to this filesystem's list of all dquots,
         * kept inside the mount structure in m_quotainfo field
         */
        xfs_qm_mplist_lock(mp);

        /*
         * We return a locked dquot to the caller, with a reference taken
         */
        xfs_dqlock(dqp);
        dqp->q_nrefs = 1;

        XQM_MPLIST_INSERT(&(XFS_QI_MPL_LIST(mp)), dqp);

        xfs_qm_mplist_unlock(mp);
        XFS_DQ_HASH_UNLOCK(h);
 dqret:
        ASSERT((ip == NULL) || xfs_isilocked(ip, XFS_ILOCK_EXCL));
        xfs_dqtrace_entry(dqp, "DQGET DONE");
        *O_dqpp = dqp;
        return (0);
}


/*
 * Release a reference to the dquot (decrement ref-count)
 * and unlock it. If there is a group quota attached to this
 * dquot, carefully release that too without tripping over
 * deadlocks'n'stuff.
 */
void
xfs_qm_dqput(
        xfs_dquot_t        *dqp)
{
        xfs_dquot_t        *gdqp;

        ASSERT(dqp->q_nrefs > 0);
        ASSERT(XFS_DQ_IS_LOCKED(dqp));
        xfs_dqtrace_entry(dqp, "DQPUT");

        if (dqp->q_nrefs != 1) {
                dqp->q_nrefs--;
                xfs_dqunlock(dqp);
                return;
        }

        /*
         * drop the dqlock and acquire the freelist and dqlock
         * in the right order; but try to get it out-of-order first
         */
        if (! xfs_qm_freelist_lock_nowait(xfs_Gqm)) {
                xfs_dqtrace_entry(dqp, "DQPUT: FLLOCK-WAIT");
                xfs_dqunlock(dqp);
                xfs_qm_freelist_lock(xfs_Gqm);
                xfs_dqlock(dqp);
        }

        while (1) {
                gdqp = NULL;

                /* We can't depend on nrefs being == 1 here */
                if (--dqp->q_nrefs == 0) {
                        xfs_dqtrace_entry(dqp, "DQPUT: ON FREELIST");
                        /*
                         * insert at end of the freelist.
                         */
                        XQM_FREELIST_INSERT(&(xfs_Gqm->qm_dqfreelist), dqp);

                        /*
                         * If we just added a udquot to the freelist, then
                         * we want to release the gdquot reference that
                         * it (probably) has. Otherwise it'll keep the
                         * gdquot from getting reclaimed.
                         */
                        if ((gdqp = dqp->q_gdquot)) {
                                /*
                                 * Avoid a recursive dqput call
                                 */
                                xfs_dqlock(gdqp);
                                dqp->q_gdquot = NULL;
                        }

                        /* xfs_qm_freelist_print(&(xfs_Gqm->qm_dqfreelist),
                           "@@@@@++ Free list (after append) @@@@@+");
                           */
                }
                xfs_dqunlock(dqp);

                /*
                 * If we had a group quota inside the user quota as a hint,
                 * release it now.
                 */
                if (! gdqp)
                        break;
                dqp = gdqp;
        }
        xfs_qm_freelist_unlock(xfs_Gqm);
}

/*
 * Release a dquot. Flush it if dirty, then dqput() it.
 * dquot must not be locked.
 */
void
xfs_qm_dqrele(
        xfs_dquot_t        *dqp)
{
        ASSERT(dqp);
        xfs_dqtrace_entry(dqp, "DQRELE");

        xfs_dqlock(dqp);
        /*
         * We don't care to flush it if the dquot is dirty here.
         * That will create stutters that we want to avoid.
         * Instead we do a delayed write when we try to reclaim
         * a dirty dquot. Also xfs_sync will take part of the burden...
         */
        xfs_qm_dqput(dqp);
}


/*
 * Write a modified dquot to disk.
 * The dquot must be locked and the flush lock too taken by caller.
 * The flush lock will not be unlocked until the dquot reaches the disk,
 * but the dquot is free to be unlocked and modified by the caller
 * in the interim. Dquot is still locked on return. This behavior is
 * identical to that of inodes.
 */
int
xfs_qm_dqflush(
        xfs_dquot_t                *dqp,
        uint                        flags)
{
        xfs_mount_t                *mp;
        xfs_buf_t                *bp;
        xfs_disk_dquot_t        *ddqp;
        int                        error;

        ASSERT(XFS_DQ_IS_LOCKED(dqp));
        ASSERT(!completion_done(&dqp->q_flush));
        xfs_dqtrace_entry(dqp, "DQFLUSH");

        /*
         * If not dirty, nada.
         */
        if (!XFS_DQ_IS_DIRTY(dqp)) {
                xfs_dqfunlock(dqp);
                return (0);
        }

        /*
         * Cant flush a pinned dquot. Wait for it.
         */
        xfs_qm_dqunpin_wait(dqp);

        /*
         * This may have been unpinned because the filesystem is shutting
         * down forcibly. If that's the case we must not write this dquot
         * to disk, because the log record didn't make it to disk!
         */
        if (XFS_FORCED_SHUTDOWN(dqp->q_mount)) {
                dqp->dq_flags &= ~(XFS_DQ_DIRTY);
                xfs_dqfunlock(dqp);
                return XFS_ERROR(EIO);
        }

        /*
         * Get the buffer containing the on-disk dquot
         * We don't need a transaction envelope because we know that the
         * the ondisk-dquot has already been allocated for.
         */
        if ((error = xfs_qm_dqtobp(NULL, dqp, &ddqp, &bp, XFS_QMOPT_DOWARN))) {
                xfs_dqtrace_entry(dqp, "DQTOBP FAIL");
                ASSERT(error != ENOENT);
                /*
                 * Quotas could have gotten turned off (ESRCH)
                 */
                xfs_dqfunlock(dqp);
                return (error);
        }

        if (xfs_qm_dqcheck(&dqp->q_core, be32_to_cpu(ddqp->d_id),
                           0, XFS_QMOPT_DOWARN, "dqflush (incore copy)")) {
                xfs_force_shutdown(dqp->q_mount, SHUTDOWN_CORRUPT_INCORE);
                return XFS_ERROR(EIO);
        }

        /* This is the only portion of data that needs to persist */
        memcpy(ddqp, &(dqp->q_core), sizeof(xfs_disk_dquot_t));

        /*
         * Clear the dirty field and remember the flush lsn for later use.
         */
        dqp->dq_flags &= ~(XFS_DQ_DIRTY);
        mp = dqp->q_mount;

        /* lsn is 64 bits */
        spin_lock(&mp->m_ail_lock);
        dqp->q_logitem.qli_flush_lsn = dqp->q_logitem.qli_item.li_lsn;
        spin_unlock(&mp->m_ail_lock);

        /*
         * Attach an iodone routine so that we can remove this dquot from the
         * AIL and release the flush lock once the dquot is synced to disk.
         */
        xfs_buf_attach_iodone(bp, (void(*)(xfs_buf_t *, xfs_log_item_t *))
                              xfs_qm_dqflush_done, &(dqp->q_logitem.qli_item));
        /*
         * If the buffer is pinned then push on the log so we won't
         * get stuck waiting in the write for too long.
         */
        if (XFS_BUF_ISPINNED(bp)) {
                xfs_dqtrace_entry(dqp, "DQFLUSH LOG FORCE");
                xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
        }

        if (flags & XFS_QMOPT_DELWRI) {
                xfs_bdwrite(mp, bp);
        } else if (flags & XFS_QMOPT_ASYNC) {
                error = xfs_bawrite(mp, bp);
        } else {
                error = xfs_bwrite(mp, bp);
        }
        xfs_dqtrace_entry(dqp, "DQFLUSH END");
        /*
         * dqp is still locked, but caller is free to unlock it now.
         */
        return (error);

}

/*
 * This is the dquot flushing I/O completion routine.  It is called
 * from interrupt level when the buffer containing the dquot is
 * flushed to disk.  It is responsible for removing the dquot logitem
 * from the AIL if it has not been re-logged, and unlocking the dquot's
 * flush lock. This behavior is very similar to that of inodes..
 */
/*ARGSUSED*/
STATIC void
xfs_qm_dqflush_done(
        xfs_buf_t                *bp,
        xfs_dq_logitem_t        *qip)
{
        xfs_dquot_t                *dqp;

        dqp = qip->qli_dquot;

        /*
         * We only want to pull the item from the AIL if its
         * location in the log has not changed since we started the flush.
         * Thus, we only bother if the dquot's lsn has
         * not changed. First we check the lsn outside the lock
         * since it's cheaper, and then we recheck while
         * holding the lock before removing the dquot from the AIL.
         */
        if ((qip->qli_item.li_flags & XFS_LI_IN_AIL) &&
            qip->qli_item.li_lsn == qip->qli_flush_lsn) {

                spin_lock(&dqp->q_mount->m_ail_lock);
                /*
                 * xfs_trans_delete_ail() drops the AIL lock.
                 */
                if (qip->qli_item.li_lsn == qip->qli_flush_lsn)
                        xfs_trans_delete_ail(dqp->q_mount,
                                             (xfs_log_item_t*)qip);
                else
                        spin_unlock(&dqp->q_mount->m_ail_lock);
        }

        /*
         * Release the dq's flush lock since we're done with it.
         */
        xfs_dqfunlock(dqp);
}

int
xfs_qm_dqlock_nowait(
        xfs_dquot_t *dqp)
{
        return mutex_trylock(&dqp->q_qlock);
}

void
xfs_dqlock(
        xfs_dquot_t *dqp)
{
        mutex_lock(&dqp->q_qlock);
}

void
xfs_dqunlock(
        xfs_dquot_t *dqp)
{
        mutex_unlock(&(dqp->q_qlock));
        if (dqp->q_logitem.qli_dquot == dqp) {
                /* Once was dqp->q_mount, but might just have been cleared */
                xfs_trans_unlocked_item(dqp->q_logitem.qli_item.li_mountp,
                                        (xfs_log_item_t*)&(dqp->q_logitem));
        }
}


void
xfs_dqunlock_nonotify(
        xfs_dquot_t *dqp)
{
        mutex_unlock(&(dqp->q_qlock));
}

void
xfs_dqlock2(
        xfs_dquot_t        *d1,
        xfs_dquot_t        *d2)
{
        if (d1 && d2) {
                ASSERT(d1 != d2);
                if (be32_to_cpu(d1->q_core.d_id) >
                    be32_to_cpu(d2->q_core.d_id)) {
                        xfs_dqlock(d2);
                        xfs_dqlock(d1);
                } else {
                        xfs_dqlock(d1);
                        xfs_dqlock(d2);
                }
        } else {
                if (d1) {
                        xfs_dqlock(d1);
                } else if (d2) {
                        xfs_dqlock(d2);
                }
        }
}


/*
 * Take a dquot out of the mount's dqlist as well as the hashlist.
 * This is called via unmount as well as quotaoff, and the purge
 * will always succeed unless there are soft (temp) references
 * outstanding.
 *
 * This returns 0 if it was purged, 1 if it wasn't. It's not an error code
 * that we're returning! XXXsup - not cool.
 */
/* ARGSUSED */
int
xfs_qm_dqpurge(
        xfs_dquot_t        *dqp)
{
        xfs_dqhash_t        *thishash;
        xfs_mount_t        *mp = dqp->q_mount;

        ASSERT(XFS_QM_IS_MPLIST_LOCKED(mp));
        ASSERT(XFS_DQ_IS_HASH_LOCKED(dqp->q_hash));

        xfs_dqlock(dqp);
        /*
         * We really can't afford to purge a dquot that is
         * referenced, because these are hard refs.
         * It shouldn't happen in general because we went thru _all_ inodes in
         * dqrele_all_inodes before calling this and didn't let the mountlock go.
         * However it is possible that we have dquots with temporary
         * references that are not attached to an inode. e.g. see xfs_setattr().
         */
        if (dqp->q_nrefs != 0) {
                xfs_dqunlock(dqp);
                XFS_DQ_HASH_UNLOCK(dqp->q_hash);
                return (1);
        }

        ASSERT(XFS_DQ_IS_ON_FREELIST(dqp));

        /*
         * If we're turning off quotas, we have to make sure that, for
         * example, we don't delete quota disk blocks while dquots are
         * in the process of getting written to those disk blocks.
         * This dquot might well be on AIL, and we can't leave it there
         * if we're turning off quotas. Basically, we need this flush
         * lock, and are willing to block on it.
         */
        if (!xfs_dqflock_nowait(dqp)) {
                /*
                 * Block on the flush lock after nudging dquot buffer,
                 * if it is incore.
                 */
                xfs_qm_dqflock_pushbuf_wait(dqp);
        }

        /*
         * XXXIf we're turning this type of quotas off, we don't care
         * about the dirty metadata sitting in this dquot. OTOH, if
         * we're unmounting, we do care, so we flush it and wait.
         */
        if (XFS_DQ_IS_DIRTY(dqp)) {
                int        error;
                xfs_dqtrace_entry(dqp, "DQPURGE ->DQFLUSH: DQDIRTY");
                /* dqflush unlocks dqflock */
                /*
                 * Given that dqpurge is a very rare occurrence, it is OK
                 * that we're holding the hashlist and mplist locks
                 * across the disk write. But, ... XXXsup
                 *
                 * We don't care about getting disk errors here. We need
                 * to purge this dquot anyway, so we go ahead regardless.
                 */
                error = xfs_qm_dqflush(dqp, XFS_QMOPT_SYNC);
                if (error)
                        xfs_fs_cmn_err(CE_WARN, mp,
                                "xfs_qm_dqpurge: dquot %p flush failed", dqp);
                xfs_dqflock(dqp);
        }
        ASSERT(dqp->q_pincount == 0);
        ASSERT(XFS_FORCED_SHUTDOWN(mp) ||
               !(dqp->q_logitem.qli_item.li_flags & XFS_LI_IN_AIL));

        thishash = dqp->q_hash;
        XQM_HASHLIST_REMOVE(thishash, dqp);
        XQM_MPLIST_REMOVE(&(XFS_QI_MPL_LIST(mp)), dqp);
        /*
         * XXX Move this to the front of the freelist, if we can get the
         * freelist lock.
         */
        ASSERT(XFS_DQ_IS_ON_FREELIST(dqp));

        dqp->q_mount = NULL;
        dqp->q_hash = NULL;
        dqp->dq_flags = XFS_DQ_INACTIVE;
        memset(&dqp->q_core, 0, sizeof(dqp->q_core));
        xfs_dqfunlock(dqp);
        xfs_dqunlock(dqp);
        XFS_DQ_HASH_UNLOCK(thishash);
        return (0);
}


#ifdef QUOTADEBUG
void
xfs_qm_dqprint(xfs_dquot_t *dqp)
{
        cmn_err(CE_DEBUG, "-----------KERNEL DQUOT----------------");
        cmn_err(CE_DEBUG, "---- dquotID =  %d",
                (int)be32_to_cpu(dqp->q_core.d_id));
        cmn_err(CE_DEBUG, "---- type    =  %s", DQFLAGTO_TYPESTR(dqp));
        cmn_err(CE_DEBUG, "---- fs      =  0x%p", dqp->q_mount);
        cmn_err(CE_DEBUG, "---- blkno   =  0x%x", (int) dqp->q_blkno);
        cmn_err(CE_DEBUG, "---- boffset =  0x%x", (int) dqp->q_bufoffset);
        cmn_err(CE_DEBUG, "---- blkhlimit =  %Lu (0x%x)",
                be64_to_cpu(dqp->q_core.d_blk_hardlimit),
                (int)be64_to_cpu(dqp->q_core.d_blk_hardlimit));
        cmn_err(CE_DEBUG, "---- blkslimit =  %Lu (0x%x)",
                be64_to_cpu(dqp->q_core.d_blk_softlimit),
                (int)be64_to_cpu(dqp->q_core.d_blk_softlimit));
        cmn_err(CE_DEBUG, "---- inohlimit =  %Lu (0x%x)",
                be64_to_cpu(dqp->q_core.d_ino_hardlimit),
                (int)be64_to_cpu(dqp->q_core.d_ino_hardlimit));
        cmn_err(CE_DEBUG, "---- inoslimit =  %Lu (0x%x)",
                be64_to_cpu(dqp->q_core.d_ino_softlimit),
                (int)be64_to_cpu(dqp->q_core.d_ino_softlimit));
        cmn_err(CE_DEBUG, "---- bcount  =  %Lu (0x%x)",
                be64_to_cpu(dqp->q_core.d_bcount),
                (int)be64_to_cpu(dqp->q_core.d_bcount));
        cmn_err(CE_DEBUG, "---- icount  =  %Lu (0x%x)",
                be64_to_cpu(dqp->q_core.d_icount),
                (int)be64_to_cpu(dqp->q_core.d_icount));
        cmn_err(CE_DEBUG, "---- btimer  =  %d",
                (int)be32_to_cpu(dqp->q_core.d_btimer));
        cmn_err(CE_DEBUG, "---- itimer  =  %d",
                (int)be32_to_cpu(dqp->q_core.d_itimer));
        cmn_err(CE_DEBUG, "---------------------------");
}
#endif

/*
 * Give the buffer a little push if it is incore and
 * wait on the flush lock.
 */
void
xfs_qm_dqflock_pushbuf_wait(
        xfs_dquot_t        *dqp)
{
        xfs_buf_t        *bp;

        /*
         * Check to see if the dquot has been flushed delayed
         * write.  If so, grab its buffer and send it
         * out immediately.  We'll be able to acquire
         * the flush lock when the I/O completes.
         */
        bp = xfs_incore(dqp->q_mount->m_ddev_targp, dqp->q_blkno,
                    XFS_QI_DQCHUNKLEN(dqp->q_mount),
                    XFS_INCORE_TRYLOCK);
        if (bp != NULL) {
                if (XFS_BUF_ISDELAYWRITE(bp)) {
                        int        error;
                        if (XFS_BUF_ISPINNED(bp)) {
                                xfs_log_force(dqp->q_mount,
                                              (xfs_lsn_t)0,
                                              XFS_LOG_FORCE);
                        }
                        error = xfs_bawrite(dqp->q_mount, bp);
                        if (error)
                                xfs_fs_cmn_err(CE_WARN, dqp->q_mount,
                                        "xfs_qm_dqflock_pushbuf_wait: "
                                        "pushbuf error %d on dqp %p, bp %p",
                                        error, dqp, bp);
                } else {
                        xfs_buf_relse(bp);
                }
        }
        xfs_dqflock(dqp);
}