text: /*
   * Copyright (c) 2000-2005 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_itable.h"
  #include "xfs_rtalloc.h"
  #include "xfs_error.h"
  #include "xfs_bmap.h"
  #include "xfs_rw.h"
  #include "xfs_attr.h"
  #include "xfs_buf_item.h"
  #include "xfs_trans_space.h"
  #include "xfs_utils.h"
  #include "xfs_qm.h"
  #include "xfs_trace.h"
  
  /*
   * The global quota manager. There is only one of these for the entire
   * system, _not_ one per file system. XQM keeps track of the overall
   * quota functionality, including maintaining the freelist and hash
   * tables of dquots.
   */
  struct mutex	xfs_Gqm_lock;
  struct xfs_qm	*xfs_Gqm;
  uint		ndquot;
  
  kmem_zone_t	*qm_dqzone;
  kmem_zone_t	*qm_dqtrxzone;
  
  static cred_t	xfs_zerocr;
  
  STATIC void	xfs_qm_list_init(xfs_dqlist_t *, char *, int);
  STATIC void	xfs_qm_list_destroy(xfs_dqlist_t *);
  
  STATIC void	xfs_qm_freelist_init(xfs_frlist_t *);
  STATIC void	xfs_qm_freelist_destroy(xfs_frlist_t *);
  
  STATIC int	xfs_qm_init_quotainos(xfs_mount_t *);
  STATIC int	xfs_qm_init_quotainfo(xfs_mount_t *);
  STATIC int	xfs_qm_shake(int, gfp_t);
  
  static struct shrinker xfs_qm_shaker = {
  	.shrink = xfs_qm_shake,
  	.seeks = DEFAULT_SEEKS,
  };
  
  #ifdef DEBUG
  extern struct mutex	qcheck_lock;
  #endif
  
  #ifdef QUOTADEBUG
  #define XQM_LIST_PRINT(l, NXT, title) \
  { \
  	xfs_dquot_t	*dqp; int i = 0; \
  	cmn_err(CE_DEBUG, "%s (#%d)", title, (int) (l)->qh_nelems); \
  	for (dqp = (l)->qh_next; dqp != NULL; dqp = dqp->NXT) { \
  		cmn_err(CE_DEBUG, "   %d.  \"%d (%s)\"   " \
  				  "bcnt = %d, icnt = %d, refs = %d", \
  			++i, (int) be32_to_cpu(dqp->q_core.d_id), \
  			DQFLAGTO_TYPESTR(dqp),	     \
  			(int) be64_to_cpu(dqp->q_core.d_bcount), \
  			(int) be64_to_cpu(dqp->q_core.d_icount), \
  			(int) dqp->q_nrefs);  } \
  }
  #else
  #define XQM_LIST_PRINT(l, NXT, title) do { } while (0)
  #endif
  
  /*
   * Initialize the XQM structure.
   * Note that there is not one quota manager per file system.
   */
  STATIC struct xfs_qm *
  xfs_Gqm_init(void)
  {
  	xfs_dqhash_t	*udqhash, *gdqhash;
  	xfs_qm_t	*xqm;
  	size_t		hsize;
  	uint		i;
  
  	/*
  	 * Initialize the dquot hash tables.
  	 */
  	udqhash = kmem_zalloc_greedy(&hsize,
  				     XFS_QM_HASHSIZE_LOW * sizeof(xfs_dqhash_t),
  				     XFS_QM_HASHSIZE_HIGH * sizeof(xfs_dqhash_t),
  				     KM_SLEEP | KM_MAYFAIL | KM_LARGE);
  	gdqhash = kmem_zalloc(hsize, KM_SLEEP | KM_LARGE);
  	hsize /= sizeof(xfs_dqhash_t);
  	ndquot = hsize << 8;
  
  	xqm = kmem_zalloc(sizeof(xfs_qm_t), KM_SLEEP);
  	xqm->qm_dqhashmask = hsize - 1;
  	xqm->qm_usr_dqhtable = udqhash;
  	xqm->qm_grp_dqhtable = gdqhash;
  	ASSERT(xqm->qm_usr_dqhtable != NULL);
  	ASSERT(xqm->qm_grp_dqhtable != NULL);
  
  	for (i = 0; i < hsize; i++) {
  		xfs_qm_list_init(&(xqm->qm_usr_dqhtable[i]), "uxdqh", i);
  		xfs_qm_list_init(&(xqm->qm_grp_dqhtable[i]), "gxdqh", i);
  	}
  
  	/*
  	 * Freelist of all dquots of all file systems
  	 */
  	xfs_qm_freelist_init(&(xqm->qm_dqfreelist));
  
  	/*
  	 * dquot zone. we register our own low-memory callback.
  	 */
  	if (!qm_dqzone) {
  		xqm->qm_dqzone = kmem_zone_init(sizeof(xfs_dquot_t),
  						"xfs_dquots");
  		qm_dqzone = xqm->qm_dqzone;
  	} else
  		xqm->qm_dqzone = qm_dqzone;
  
  	register_shrinker(&xfs_qm_shaker);
  
  	/*
  	 * The t_dqinfo portion of transactions.
  	 */
  	if (!qm_dqtrxzone) {
  		xqm->qm_dqtrxzone = kmem_zone_init(sizeof(xfs_dquot_acct_t),
  						   "xfs_dqtrx");
  		qm_dqtrxzone = xqm->qm_dqtrxzone;
  	} else
  		xqm->qm_dqtrxzone = qm_dqtrxzone;
  
  	atomic_set(&xqm->qm_totaldquots, 0);
  	xqm->qm_dqfree_ratio = XFS_QM_DQFREE_RATIO;
  	xqm->qm_nrefs = 0;
  #ifdef DEBUG
  	mutex_init(&qcheck_lock);
  #endif
  	return xqm;
  }
  
  /*
   * Destroy the global quota manager when its reference count goes to zero.
   */
  STATIC void
  xfs_qm_destroy(
  	struct xfs_qm	*xqm)
  {
  	int		hsize, i;
  
  	ASSERT(xqm != NULL);
  	ASSERT(xqm->qm_nrefs == 0);
  	unregister_shrinker(&xfs_qm_shaker);
  	hsize = xqm->qm_dqhashmask + 1;
  	for (i = 0; i < hsize; i++) {
  		xfs_qm_list_destroy(&(xqm->qm_usr_dqhtable[i]));
  		xfs_qm_list_destroy(&(xqm->qm_grp_dqhtable[i]));
  	}
  	kmem_free(xqm->qm_usr_dqhtable);
  	kmem_free(xqm->qm_grp_dqhtable);
  	xqm->qm_usr_dqhtable = NULL;
  	xqm->qm_grp_dqhtable = NULL;
  	xqm->qm_dqhashmask = 0;
  	xfs_qm_freelist_destroy(&(xqm->qm_dqfreelist));
  #ifdef DEBUG
  	mutex_destroy(&qcheck_lock);
  #endif
  	kmem_free(xqm);
  }
  
  /*
   * Called at mount time to let XQM know that another file system is
   * starting quotas. This isn't crucial information as the individual mount
   * structures are pretty independent, but it helps the XQM keep a
   * global view of what's going on.
   */
  /* ARGSUSED */
  STATIC int
  xfs_qm_hold_quotafs_ref(
  	struct xfs_mount *mp)
  {
  	/*
  	 * Need to lock the xfs_Gqm structure for things like this. For example,
  	 * the structure could disappear between the entry to this routine and
  	 * a HOLD operation if not locked.
  	 */
  	mutex_lock(&xfs_Gqm_lock);
  
  	if (xfs_Gqm == NULL)
  		xfs_Gqm = xfs_Gqm_init();
  	/*
  	 * We can keep a list of all filesystems with quotas mounted for
  	 * debugging and statistical purposes, but ...
  	 * Just take a reference and get out.
  	 */
  	xfs_Gqm->qm_nrefs++;
  	mutex_unlock(&xfs_Gqm_lock);
  
  	return 0;
  }
  
  
  /*
   * Release the reference that a filesystem took at mount time,
   * so that we know when we need to destroy the entire quota manager.
   */
  /* ARGSUSED */
  STATIC void
  xfs_qm_rele_quotafs_ref(
  	struct xfs_mount *mp)
  {
  	xfs_dquot_t	*dqp, *nextdqp;
  
  	ASSERT(xfs_Gqm);
  	ASSERT(xfs_Gqm->qm_nrefs > 0);
  
  	/*
  	 * Go thru the freelist and destroy all inactive dquots.
  	 */
  	xfs_qm_freelist_lock(xfs_Gqm);
  
  	for (dqp = xfs_Gqm->qm_dqfreelist.qh_next;
  	     dqp != (xfs_dquot_t *)&(xfs_Gqm->qm_dqfreelist); ) {
  		xfs_dqlock(dqp);
  		nextdqp = dqp->dq_flnext;
  		if (dqp->dq_flags & XFS_DQ_INACTIVE) {
  			ASSERT(dqp->q_mount == NULL);
  			ASSERT(! XFS_DQ_IS_DIRTY(dqp));
  			ASSERT(dqp->HL_PREVP == NULL);
  			ASSERT(dqp->MPL_PREVP == NULL);
  			XQM_FREELIST_REMOVE(dqp);
  			xfs_dqunlock(dqp);
  			xfs_qm_dqdestroy(dqp);
  		} else {
  			xfs_dqunlock(dqp);
  		}
  		dqp = nextdqp;
  	}
  	xfs_qm_freelist_unlock(xfs_Gqm);
  
  	/*
  	 * Destroy the entire XQM. If somebody mounts with quotaon, this'll
  	 * be restarted.
  	 */
  	mutex_lock(&xfs_Gqm_lock);
  	if (--xfs_Gqm->qm_nrefs == 0) {
  		xfs_qm_destroy(xfs_Gqm);
  		xfs_Gqm = NULL;
  	}
  	mutex_unlock(&xfs_Gqm_lock);
  }
  
  /*
   * Just destroy the quotainfo structure.
   */
  void
  xfs_qm_unmount(
  	struct xfs_mount	*mp)
  {
  	if (mp->m_quotainfo) {
  		xfs_qm_dqpurge_all(mp, XFS_QMOPT_QUOTALL | XFS_QMOPT_UMOUNTING);
  		xfs_qm_destroy_quotainfo(mp);
  	}
  }
  
  
  /*
   * This is called from xfs_mountfs to start quotas and initialize all
   * necessary data structures like quotainfo.  This is also responsible for
   * running a quotacheck as necessary.  We are guaranteed that the superblock
   * is consistently read in at this point.
   *
   * If we fail here, the mount will continue with quota turned off. We don't
   * need to inidicate success or failure at all.
   */
  void
  xfs_qm_mount_quotas(
  	xfs_mount_t	*mp)
  {
  	int		error = 0;
  	uint		sbf;
  
  	/*
  	 * If quotas on realtime volumes is not supported, we disable
  	 * quotas immediately.
  	 */
  	if (mp->m_sb.sb_rextents) {
  		cmn_err(CE_NOTE,
  			"Cannot turn on quotas for realtime filesystem %s",
  			mp->m_fsname);
  		mp->m_qflags = 0;
  		goto write_changes;
  	}
  
  	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
  
  	/*
  	 * Allocate the quotainfo structure inside the mount struct, and
  	 * create quotainode(s), and change/rev superblock if necessary.
  	 */
  	error = xfs_qm_init_quotainfo(mp);
  	if (error) {
  		/*
  		 * We must turn off quotas.
  		 */
  		ASSERT(mp->m_quotainfo == NULL);
  		mp->m_qflags = 0;
  		goto write_changes;
  	}
  	/*
  	 * If any of the quotas are not consistent, do a quotacheck.
  	 */
  	if (XFS_QM_NEED_QUOTACHECK(mp)) {
  		error = xfs_qm_quotacheck(mp);
  		if (error) {
  			/* Quotacheck failed and disabled quotas. */
  			return;
  		}
  	}
  	/* 
  	 * If one type of quotas is off, then it will lose its
  	 * quotachecked status, since we won't be doing accounting for
  	 * that type anymore.
  	 */
  	if (!XFS_IS_UQUOTA_ON(mp))
  		mp->m_qflags &= ~XFS_UQUOTA_CHKD;
  	if (!(XFS_IS_GQUOTA_ON(mp) || XFS_IS_PQUOTA_ON(mp)))
  		mp->m_qflags &= ~XFS_OQUOTA_CHKD;
  
   write_changes:
  	/*
  	 * We actually don't have to acquire the m_sb_lock at all.
  	 * This can only be called from mount, and that's single threaded. XXX
  	 */
  	spin_lock(&mp->m_sb_lock);
  	sbf = mp->m_sb.sb_qflags;
  	mp->m_sb.sb_qflags = mp->m_qflags & XFS_MOUNT_QUOTA_ALL;
  	spin_unlock(&mp->m_sb_lock);
  
  	if (sbf != (mp->m_qflags & XFS_MOUNT_QUOTA_ALL)) {
  		if (xfs_qm_write_sb_changes(mp, XFS_SB_QFLAGS)) {
  			/*
  			 * We could only have been turning quotas off.
  			 * We aren't in very good shape actually because
  			 * the incore structures are convinced that quotas are
  			 * off, but the on disk superblock doesn't know that !
  			 */
  			ASSERT(!(XFS_IS_QUOTA_RUNNING(mp)));
  			xfs_fs_cmn_err(CE_ALERT, mp,
  				"XFS mount_quotas: Superblock update failed!");
  		}
  	}
  
  	if (error) {
  		xfs_fs_cmn_err(CE_WARN, mp,
  			"Failed to initialize disk quotas.");
  		return;
  	}
  
  #ifdef QUOTADEBUG
  	if (XFS_IS_QUOTA_ON(mp))
  		xfs_qm_internalqcheck(mp);
  #endif
  }
  
  /*
   * Called from the vfsops layer.
   */
  void
  xfs_qm_unmount_quotas(
  	xfs_mount_t	*mp)
  {
  	/*
  	 * Release the dquots that root inode, et al might be holding,
  	 * before we flush quotas and blow away the quotainfo structure.
  	 */
  	ASSERT(mp->m_rootip);
  	xfs_qm_dqdetach(mp->m_rootip);
  	if (mp->m_rbmip)
  		xfs_qm_dqdetach(mp->m_rbmip);
  	if (mp->m_rsumip)
  		xfs_qm_dqdetach(mp->m_rsumip);
  
  	/*
  	 * Release the quota inodes.
  	 */
  	if (mp->m_quotainfo) {
  		if (mp->m_quotainfo->qi_uquotaip) {
  			IRELE(mp->m_quotainfo->qi_uquotaip);
  			mp->m_quotainfo->qi_uquotaip = NULL;
  		}
  		if (mp->m_quotainfo->qi_gquotaip) {
  			IRELE(mp->m_quotainfo->qi_gquotaip);
  			mp->m_quotainfo->qi_gquotaip = NULL;
  		}
  	}
  }
  
  /*
   * Flush all dquots of the given file system to disk. The dquots are
   * _not_ purged from memory here, just their data written to disk.
   */
  STATIC int
  xfs_qm_dqflush_all(
  	xfs_mount_t	*mp,
  	int		flags)
  {
  	int		recl;
  	xfs_dquot_t	*dqp;
  	int		niters;
  	int		error;
  
  	if (mp->m_quotainfo == NULL)
  		return 0;
  	niters = 0;
  again:
  	xfs_qm_mplist_lock(mp);
  	FOREACH_DQUOT_IN_MP(dqp, mp) {
  		xfs_dqlock(dqp);
  		if (! XFS_DQ_IS_DIRTY(dqp)) {
  			xfs_dqunlock(dqp);
  			continue;
  		}
  
  		/* XXX a sentinel would be better */
  		recl = XFS_QI_MPLRECLAIMS(mp);
  		if (!xfs_dqflock_nowait(dqp)) {
  			/*
  			 * If we can't grab the flush lock then 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.
  			 */
  			xfs_qm_dqflock_pushbuf_wait(dqp);
  		}
  		/*
  		 * Let go of the mplist lock. We don't want to hold it
  		 * across a disk write.
  		 */
  		xfs_qm_mplist_unlock(mp);
  		error = xfs_qm_dqflush(dqp, flags);
  		xfs_dqunlock(dqp);
  		if (error)
  			return error;
  
  		xfs_qm_mplist_lock(mp);
  		if (recl != XFS_QI_MPLRECLAIMS(mp)) {
  			xfs_qm_mplist_unlock(mp);
  			/* XXX restart limit */
  			goto again;
  		}
  	}
  
  	xfs_qm_mplist_unlock(mp);
  	/* return ! busy */
  	return 0;
  }
  /*
   * Release the group dquot pointers the user dquots may be
   * carrying around as a hint. mplist is locked on entry and exit.
   */
  STATIC void
  xfs_qm_detach_gdquots(
  	xfs_mount_t	*mp)
  {
  	xfs_dquot_t	*dqp, *gdqp;
  	int		nrecl;
  
   again:
  	ASSERT(XFS_QM_IS_MPLIST_LOCKED(mp));
  	dqp = XFS_QI_MPLNEXT(mp);
  	while (dqp) {
  		xfs_dqlock(dqp);
  		if ((gdqp = dqp->q_gdquot)) {
  			xfs_dqlock(gdqp);
  			dqp->q_gdquot = NULL;
  		}
  		xfs_dqunlock(dqp);
  
  		if (gdqp) {
  			/*
  			 * Can't hold the mplist lock across a dqput.
  			 * XXXmust convert to marker based iterations here.
  			 */
  			nrecl = XFS_QI_MPLRECLAIMS(mp);
  			xfs_qm_mplist_unlock(mp);
  			xfs_qm_dqput(gdqp);
  
  			xfs_qm_mplist_lock(mp);
  			if (nrecl != XFS_QI_MPLRECLAIMS(mp))
  				goto again;
  		}
  		dqp = dqp->MPL_NEXT;
  	}
  }
  
  /*
   * Go through all the incore dquots of this file system and take them
   * off the mplist and hashlist, if the dquot type matches the dqtype
   * parameter. This is used when turning off quota accounting for
   * users and/or groups, as well as when the filesystem is unmounting.
   */
  STATIC int
  xfs_qm_dqpurge_int(
  	xfs_mount_t	*mp,
  	uint		flags) /* QUOTAOFF/UMOUNTING/UQUOTA/PQUOTA/GQUOTA */
  {
  	xfs_dquot_t	*dqp;
  	uint		dqtype;
  	int		nrecl;
  	xfs_dquot_t	*nextdqp;
  	int		nmisses;
  
  	if (mp->m_quotainfo == NULL)
  		return 0;
  
  	dqtype = (flags & XFS_QMOPT_UQUOTA) ? XFS_DQ_USER : 0;
  	dqtype |= (flags & XFS_QMOPT_PQUOTA) ? XFS_DQ_PROJ : 0;
  	dqtype |= (flags & XFS_QMOPT_GQUOTA) ? XFS_DQ_GROUP : 0;
  
  	xfs_qm_mplist_lock(mp);
  
  	/*
  	 * In the first pass through all incore dquots of this filesystem,
  	 * we release the group dquot pointers the user dquots may be
  	 * carrying around as a hint. We need to do this irrespective of
  	 * what's being turned off.
  	 */
  	xfs_qm_detach_gdquots(mp);
  
        again:
  	nmisses = 0;
  	ASSERT(XFS_QM_IS_MPLIST_LOCKED(mp));
  	/*
  	 * Try to get rid of all of the unwanted dquots. The idea is to
  	 * get them off mplist and hashlist, but leave them on freelist.
  	 */
  	dqp = XFS_QI_MPLNEXT(mp);
  	while (dqp) {
  		/*
  		 * It's OK to look at the type without taking dqlock here.
  		 * We're holding the mplist lock here, and that's needed for
  		 * a dqreclaim.
  		 */
  		if ((dqp->dq_flags & dqtype) == 0) {
  			dqp = dqp->MPL_NEXT;
  			continue;
  		}
  
  		if (!mutex_trylock(&dqp->q_hash->qh_lock)) {
  			nrecl = XFS_QI_MPLRECLAIMS(mp);
  			xfs_qm_mplist_unlock(mp);
  			mutex_lock(&dqp->q_hash->qh_lock);
  			xfs_qm_mplist_lock(mp);
  
  			/*
  			 * XXXTheoretically, we can get into a very long
  			 * ping pong game here.
  			 * No one can be adding dquots to the mplist at
  			 * this point, but somebody might be taking things off.
  			 */
  			if (nrecl != XFS_QI_MPLRECLAIMS(mp)) {
  				mutex_unlock(&dqp->q_hash->qh_lock);
  				goto again;
  			}
  		}
  
  		/*
  		 * Take the dquot off the mplist and hashlist. It may remain on
  		 * freelist in INACTIVE state.
  		 */
  		nextdqp = dqp->MPL_NEXT;
  		nmisses += xfs_qm_dqpurge(dqp);
  		dqp = nextdqp;
  	}
  	xfs_qm_mplist_unlock(mp);
  	return nmisses;
  }
  
  int
  xfs_qm_dqpurge_all(
  	xfs_mount_t	*mp,
  	uint		flags)
  {
  	int		ndquots;
  
  	/*
  	 * Purge the dquot cache.
  	 * None of the dquots should really be busy at this point.
  	 */
  	if (mp->m_quotainfo) {
  		while ((ndquots = xfs_qm_dqpurge_int(mp, flags))) {
  			delay(ndquots * 10);
  		}
  	}
  	return 0;
  }
  
  STATIC int
  xfs_qm_dqattach_one(
  	xfs_inode_t	*ip,
  	xfs_dqid_t	id,
  	uint		type,
  	uint		doalloc,
  	xfs_dquot_t	*udqhint, /* hint */
  	xfs_dquot_t	**IO_idqpp)
  {
  	xfs_dquot_t	*dqp;
  	int		error;
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
  	error = 0;
  
  	/*
  	 * See if we already have it in the inode itself. IO_idqpp is
  	 * &i_udquot or &i_gdquot. This made the code look weird, but
  	 * made the logic a lot simpler.
  	 */
  	dqp = *IO_idqpp;
  	if (dqp) {
  		trace_xfs_dqattach_found(dqp);
  		return 0;
  	}
  
  	/*
  	 * udqhint is the i_udquot field in inode, and is non-NULL only
  	 * when the type arg is group/project. Its purpose is to save a
  	 * lookup by dqid (xfs_qm_dqget) by caching a group dquot inside
  	 * the user dquot.
  	 */
  	if (udqhint) {
  		ASSERT(type == XFS_DQ_GROUP || type == XFS_DQ_PROJ);
  		xfs_dqlock(udqhint);
  
  		/*
  		 * No need to take dqlock to look at the id.
  		 *
  		 * The ID can't change until it gets reclaimed, and it won't
  		 * be reclaimed as long as we have a ref from inode and we
  		 * hold the ilock.
  		 */
  		dqp = udqhint->q_gdquot;
  		if (dqp && be32_to_cpu(dqp->q_core.d_id) == id) {
  			xfs_dqlock(dqp);
  			XFS_DQHOLD(dqp);
  			ASSERT(*IO_idqpp == NULL);
  			*IO_idqpp = dqp;
  
  			xfs_dqunlock(dqp);
  			xfs_dqunlock(udqhint);
  			return 0;
  		}
  
  		/*
  		 * We can't hold a dquot lock when we call the dqget code.
  		 * We'll deadlock in no time, because of (not conforming to)
  		 * lock ordering - the inodelock comes before any dquot lock,
  		 * and we may drop and reacquire the ilock in xfs_qm_dqget().
  		 */
  		xfs_dqunlock(udqhint);
  	}
  
  	/*
  	 * Find the dquot from somewhere. This bumps the
  	 * reference count of dquot and returns it locked.
  	 * 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.
  	 */
  	error = xfs_qm_dqget(ip->i_mount, ip, id, type, XFS_QMOPT_DOWARN, &dqp);
  	if (error)
  		return error;
  
  	trace_xfs_dqattach_get(dqp);
  
  	/*
  	 * dqget may have dropped and re-acquired the ilock, but it guarantees
  	 * that the dquot returned is the one that should go in the inode.
  	 */
  	*IO_idqpp = dqp;
  	xfs_dqunlock(dqp);
  	return 0;
  }
  
  
  /*
   * Given a udquot and gdquot, attach a ptr to the group dquot in the
   * udquot as a hint for future lookups. The idea sounds simple, but the
   * execution isn't, because the udquot might have a group dquot attached
   * already and getting rid of that gets us into lock ordering constraints.
   * The process is complicated more by the fact that the dquots may or may not
   * be locked on entry.
   */
  STATIC void
  xfs_qm_dqattach_grouphint(
  	xfs_dquot_t	*udq,
  	xfs_dquot_t	*gdq)
  {
  	xfs_dquot_t	*tmp;
  
  	xfs_dqlock(udq);
  
  	if ((tmp = udq->q_gdquot)) {
  		if (tmp == gdq) {
  			xfs_dqunlock(udq);
  			return;
  		}
  
  		udq->q_gdquot = NULL;
  		/*
  		 * We can't keep any dqlocks when calling dqrele,
  		 * because the freelist lock comes before dqlocks.
  		 */
  		xfs_dqunlock(udq);
  		/*
  		 * we took a hard reference once upon a time in dqget,
  		 * so give it back when the udquot no longer points at it
  		 * dqput() does the unlocking of the dquot.
  		 */
  		xfs_qm_dqrele(tmp);
  
  		xfs_dqlock(udq);
  		xfs_dqlock(gdq);
  
  	} else {
  		ASSERT(XFS_DQ_IS_LOCKED(udq));
  		xfs_dqlock(gdq);
  	}
  
  	ASSERT(XFS_DQ_IS_LOCKED(udq));
  	ASSERT(XFS_DQ_IS_LOCKED(gdq));
  	/*
  	 * Somebody could have attached a gdquot here,
  	 * when we dropped the uqlock. If so, just do nothing.
  	 */
  	if (udq->q_gdquot == NULL) {
  		XFS_DQHOLD(gdq);
  		udq->q_gdquot = gdq;
  	}
  
  	xfs_dqunlock(gdq);
  	xfs_dqunlock(udq);
  }
  
  
  /*
   * Given a locked inode, attach dquot(s) to it, taking U/G/P-QUOTAON
   * into account.
   * If XFS_QMOPT_DQALLOC, the dquot(s) will be allocated if needed.
   * Inode may get unlocked and relocked in here, and the caller must deal with
   * the consequences.
   */
  int
  xfs_qm_dqattach_locked(
  	xfs_inode_t	*ip,
  	uint		flags)
  {
  	xfs_mount_t	*mp = ip->i_mount;
  	uint		nquotas = 0;
  	int		error = 0;
  
  	if (!XFS_IS_QUOTA_RUNNING(mp) ||
  	    !XFS_IS_QUOTA_ON(mp) ||
  	    !XFS_NOT_DQATTACHED(mp, ip) ||
  	    ip->i_ino == mp->m_sb.sb_uquotino ||
  	    ip->i_ino == mp->m_sb.sb_gquotino)
  		return 0;
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
  
  	if (XFS_IS_UQUOTA_ON(mp)) {
  		error = xfs_qm_dqattach_one(ip, ip->i_d.di_uid, XFS_DQ_USER,
  						flags & XFS_QMOPT_DQALLOC,
  						NULL, &ip->i_udquot);
  		if (error)
  			goto done;
  		nquotas++;
  	}
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
  	if (XFS_IS_OQUOTA_ON(mp)) {
  		error = XFS_IS_GQUOTA_ON(mp) ?
  			xfs_qm_dqattach_one(ip, ip->i_d.di_gid, XFS_DQ_GROUP,
  						flags & XFS_QMOPT_DQALLOC,
  						ip->i_udquot, &ip->i_gdquot) :
  			xfs_qm_dqattach_one(ip, ip->i_d.di_projid, XFS_DQ_PROJ,
  						flags & XFS_QMOPT_DQALLOC,
  						ip->i_udquot, &ip->i_gdquot);
  		/*
  		 * Don't worry about the udquot that we may have
  		 * attached above. It'll get detached, if not already.
  		 */
  		if (error)
  			goto done;
  		nquotas++;
  	}
  
  	/*
  	 * Attach this group quota to the user quota as a hint.
  	 * This WON'T, in general, result in a thrash.
  	 */
  	if (nquotas == 2) {
  		ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
  		ASSERT(ip->i_udquot);
  		ASSERT(ip->i_gdquot);
  
  		/*
  		 * We may or may not have the i_udquot locked at this point,
  		 * but this check is OK since we don't depend on the i_gdquot to
  		 * be accurate 100% all the time. It is just a hint, and this
  		 * will succeed in general.
  		 */
  		if (ip->i_udquot->q_gdquot == ip->i_gdquot)
  			goto done;
  		/*
  		 * Attach i_gdquot to the gdquot hint inside the i_udquot.
  		 */
  		xfs_qm_dqattach_grouphint(ip->i_udquot, ip->i_gdquot);
  	}
  
   done:
  #ifdef QUOTADEBUG
  	if (! error) {
  		if (XFS_IS_UQUOTA_ON(mp))
  			ASSERT(ip->i_udquot);
  		if (XFS_IS_OQUOTA_ON(mp))
  			ASSERT(ip->i_gdquot);
  	}
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
  #endif
  	return error;
  }
  
  int
  xfs_qm_dqattach(
  	struct xfs_inode	*ip,
  	uint			flags)
  {
  	int			error;
  
  	xfs_ilock(ip, XFS_ILOCK_EXCL);
  	error = xfs_qm_dqattach_locked(ip, flags);
  	xfs_iunlock(ip, XFS_ILOCK_EXCL);
  
  	return error;
  }
  
  /*
   * Release dquots (and their references) if any.
   * The inode should be locked EXCL except when this's called by
   * xfs_ireclaim.
   */
  void
  xfs_qm_dqdetach(
  	xfs_inode_t	*ip)
  {
  	if (!(ip->i_udquot || ip->i_gdquot))
  		return;
  
  	trace_xfs_dquot_dqdetach(ip);
  
  	ASSERT(ip->i_ino != ip->i_mount->m_sb.sb_uquotino);
  	ASSERT(ip->i_ino != ip->i_mount->m_sb.sb_gquotino);
  	if (ip->i_udquot) {
  		xfs_qm_dqrele(ip->i_udquot);
  		ip->i_udquot = NULL;
  	}
  	if (ip->i_gdquot) {
  		xfs_qm_dqrele(ip->i_gdquot);
  		ip->i_gdquot = NULL;
  	}
  }
  
  int
  xfs_qm_sync(
  	xfs_mount_t	*mp,
  	int		flags)
  {
  	int		recl, restarts;
  	xfs_dquot_t	*dqp;
  	uint		flush_flags;
  	int		error;
  
  	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
  		return 0;
  
  	flush_flags = (flags & SYNC_WAIT) ? XFS_QMOPT_SYNC : XFS_QMOPT_DELWRI;
  	restarts = 0;
  
    again:
  	xfs_qm_mplist_lock(mp);
  	/*
  	 * dqpurge_all() also takes the mplist lock and iterate thru all dquots
  	 * in quotaoff. However, if the QUOTA_ACTIVE bits are not cleared
  	 * when we have the mplist lock, we know that dquots will be consistent
  	 * as long as we have it locked.
  	 */
  	if (! XFS_IS_QUOTA_ON(mp)) {
  		xfs_qm_mplist_unlock(mp);
  		return 0;
  	}
  	FOREACH_DQUOT_IN_MP(dqp, mp) {
  		/*
  		 * If this is vfs_sync calling, then skip the dquots that
  		 * don't 'seem' to be dirty. ie. don't acquire dqlock.
  		 * This is very similar to what xfs_sync does with inodes.
  		 */
  		if (flags & SYNC_TRYLOCK) {
  			if (!XFS_DQ_IS_DIRTY(dqp))
  				continue;
  			if (!xfs_qm_dqlock_nowait(dqp))
  				continue;
  		} else {
  			xfs_dqlock(dqp);
  		}
  
  		/*
  		 * Now, find out for sure if this dquot is dirty or not.
  		 */
  		if (! XFS_DQ_IS_DIRTY(dqp)) {
  			xfs_dqunlock(dqp);
  			continue;
  		}
  
  		/* XXX a sentinel would be better */
  		recl = XFS_QI_MPLRECLAIMS(mp);
  		if (!xfs_dqflock_nowait(dqp)) {
  			if (flags & SYNC_TRYLOCK) {
  				xfs_dqunlock(dqp);
  				continue;
  			}
  			/*
  			 * If we can't grab the flush lock then if the caller
  			 * really wanted us to give this our best shot, so
  			 * see if we can give a push to the buffer before we wait
  			 * on the flush lock. At this point, we know that
  			 * even though the dquot is being flushed,
  			 * it has (new) dirty data.
  			 */
  			xfs_qm_dqflock_pushbuf_wait(dqp);
  		}
  		/*
  		 * Let go of the mplist lock. We don't want to hold it
  		 * across a disk write
  		 */
  		xfs_qm_mplist_unlock(mp);
  		error = xfs_qm_dqflush(dqp, flush_flags);
  		xfs_dqunlock(dqp);
  		if (error && XFS_FORCED_SHUTDOWN(mp))
  			return 0;	/* Need to prevent umount failure */
  		else if (error)
  			return error;
  
  		xfs_qm_mplist_lock(mp);
  		if (recl != XFS_QI_MPLRECLAIMS(mp)) {
  			if (++restarts >= XFS_QM_SYNC_MAX_RESTARTS)
  				break;
  
  			xfs_qm_mplist_unlock(mp);
  			goto again;
  		}
  	}
  
  	xfs_qm_mplist_unlock(mp);
  	return 0;
  }
  
  /*
   * The hash chains and the mplist use the same xfs_dqhash structure as
   * their list head, but we can take the mplist qh_lock and one of the
   * hash qh_locks at the same time without any problem as they aren't
   * related.
   */
  static struct lock_class_key xfs_quota_mplist_class;
  
  /*
   * This initializes all the quota information that's kept in the
   * mount structure
   */
  STATIC int
  xfs_qm_init_quotainfo(
  	xfs_mount_t	*mp)
  {
  	xfs_quotainfo_t *qinf;
  	int		error;
  	xfs_dquot_t	*dqp;
  
  	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
  
  	/*
  	 * Tell XQM that we exist as soon as possible.
  	 */
  	if ((error = xfs_qm_hold_quotafs_ref(mp))) {
  		return error;
  	}
  
  	qinf = mp->m_quotainfo = kmem_zalloc(sizeof(xfs_quotainfo_t), KM_SLEEP);
  
  	/*
  	 * See if quotainodes are setup, and if not, allocate them,
  	 * and change the superblock accordingly.
  	 */
  	if ((error = xfs_qm_init_quotainos(mp))) {
  		kmem_free(qinf);
  		mp->m_quotainfo = NULL;
  		return error;
  	}
  
  	xfs_qm_list_init(&qinf->qi_dqlist, "mpdqlist", 0);
  	lockdep_set_class(&qinf->qi_dqlist.qh_lock, &xfs_quota_mplist_class);
  
  	qinf->qi_dqreclaims = 0;
  
  	/* mutex used to serialize quotaoffs */
  	mutex_init(&qinf->qi_quotaofflock);
  
  	/* Precalc some constants */
  	qinf->qi_dqchunklen = XFS_FSB_TO_BB(mp, XFS_DQUOT_CLUSTER_SIZE_FSB);
  	ASSERT(qinf->qi_dqchunklen);
  	qinf->qi_dqperchunk = BBTOB(qinf->qi_dqchunklen);
  	do_div(qinf->qi_dqperchunk, sizeof(xfs_dqblk_t));
  
  	mp->m_qflags |= (mp->m_sb.sb_qflags & XFS_ALL_QUOTA_CHKD);
  
  	/*
  	 * We try to get the limits from the superuser's limits fields.
  	 * This is quite hacky, but it is standard quota practice.
  	 * We look at the USR dquot with id == 0 first, but if user quotas
  	 * are not enabled we goto the GRP dquot with id == 0.
  	 * We don't really care to keep separate default limits for user
  	 * and group quotas, at least not at this point.
  	 */
  	error = xfs_qm_dqget(mp, NULL, (xfs_dqid_t)0,
  			     XFS_IS_UQUOTA_RUNNING(mp) ? XFS_DQ_USER : 
  			     (XFS_IS_GQUOTA_RUNNING(mp) ? XFS_DQ_GROUP :
  				XFS_DQ_PROJ),
  			     XFS_QMOPT_DQSUSER|XFS_QMOPT_DOWARN,
  			     &dqp);
  	if (! error) {
  		xfs_disk_dquot_t	*ddqp = &dqp->q_core;
  
  		/*
  		 * The warnings and timers set the grace period given to
  		 * a user or group before he or she can not perform any
  		 * more writing. If it is zero, a default is used.
  		 */
  		qinf->qi_btimelimit = ddqp->d_btimer ?
  			be32_to_cpu(ddqp->d_btimer) : XFS_QM_BTIMELIMIT;
  		qinf->qi_itimelimit = ddqp->d_itimer ?
  			be32_to_cpu(ddqp->d_itimer) : XFS_QM_ITIMELIMIT;
  		qinf->qi_rtbtimelimit = ddqp->d_rtbtimer ?
  			be32_to_cpu(ddqp->d_rtbtimer) : XFS_QM_RTBTIMELIMIT;
  		qinf->qi_bwarnlimit = ddqp->d_bwarns ?
  			be16_to_cpu(ddqp->d_bwarns) : XFS_QM_BWARNLIMIT;
  		qinf->qi_iwarnlimit = ddqp->d_iwarns ?
  			be16_to_cpu(ddqp->d_iwarns) : XFS_QM_IWARNLIMIT;
  		qinf->qi_rtbwarnlimit = ddqp->d_rtbwarns ?
  			be16_to_cpu(ddqp->d_rtbwarns) : XFS_QM_RTBWARNLIMIT;
  		qinf->qi_bhardlimit = be64_to_cpu(ddqp->d_blk_hardlimit);
  		qinf->qi_bsoftlimit = be64_to_cpu(ddqp->d_blk_softlimit);
  		qinf->qi_ihardlimit = be64_to_cpu(ddqp->d_ino_hardlimit);
  		qinf->qi_isoftlimit = be64_to_cpu(ddqp->d_ino_softlimit);
  		qinf->qi_rtbhardlimit = be64_to_cpu(ddqp->d_rtb_hardlimit);
  		qinf->qi_rtbsoftlimit = be64_to_cpu(ddqp->d_rtb_softlimit);
   
  		/*
  		 * We sent the XFS_QMOPT_DQSUSER flag to dqget because
  		 * we don't want this dquot cached. We haven't done a
  		 * quotacheck yet, and quotacheck doesn't like incore dquots.
  		 */
  		xfs_qm_dqdestroy(dqp);
  	} else {
  		qinf->qi_btimelimit = XFS_QM_BTIMELIMIT;
  		qinf->qi_itimelimit = XFS_QM_ITIMELIMIT;
  		qinf->qi_rtbtimelimit = XFS_QM_RTBTIMELIMIT;
  		qinf->qi_bwarnlimit = XFS_QM_BWARNLIMIT;
  		qinf->qi_iwarnlimit = XFS_QM_IWARNLIMIT;
  		qinf->qi_rtbwarnlimit = XFS_QM_RTBWARNLIMIT;
  	}
  
  	return 0;
  }
  
  
  /*
   * Gets called when unmounting a filesystem or when all quotas get
   * turned off.
   * This purges the quota inodes, destroys locks and frees itself.
   */
  void
  xfs_qm_destroy_quotainfo(
  	xfs_mount_t	*mp)
  {
  	xfs_quotainfo_t *qi;
  
  	qi = mp->m_quotainfo;
  	ASSERT(qi != NULL);
  	ASSERT(xfs_Gqm != NULL);
  
  	/*
  	 * Release the reference that XQM kept, so that we know
  	 * when the XQM structure should be freed. We cannot assume
  	 * that xfs_Gqm is non-null after this point.
  	 */
  	xfs_qm_rele_quotafs_ref(mp);
  
  	xfs_qm_list_destroy(&qi->qi_dqlist);
  
  	if (qi->qi_uquotaip) {
  		IRELE(qi->qi_uquotaip);
  		qi->qi_uquotaip = NULL; /* paranoia */
  	}
  	if (qi->qi_gquotaip) {
  		IRELE(qi->qi_gquotaip);
  		qi->qi_gquotaip = NULL;
  	}
  	mutex_destroy(&qi->qi_quotaofflock);
  	kmem_free(qi);
  	mp->m_quotainfo = NULL;
  }
  
  
  
  /* ------------------- PRIVATE STATIC FUNCTIONS ----------------------- */
  
  /* ARGSUSED */
  STATIC void
  xfs_qm_list_init(
  	xfs_dqlist_t	*list,
  	char		*str,
  	int		n)
  {
  	mutex_init(&list->qh_lock);
  	list->qh_next = NULL;
  	list->qh_version = 0;
  	list->qh_nelems = 0;
  }
  
  STATIC void
  xfs_qm_list_destroy(
  	xfs_dqlist_t	*list)
  {
  	mutex_destroy(&(list->qh_lock));
  }
  
  
  /*
   * Stripped down version of dqattach. This doesn't attach, or even look at the
   * dquots attached to the inode. The rationale is that there won't be any
   * attached at the time this is called from quotacheck.
   */
  STATIC int
  xfs_qm_dqget_noattach(
  	xfs_inode_t	*ip,
  	xfs_dquot_t	**O_udqpp,
  	xfs_dquot_t	**O_gdqpp)
  {
  	int		error;
  	xfs_mount_t	*mp;
  	xfs_dquot_t	*udqp, *gdqp;
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
  	mp = ip->i_mount;
  	udqp = NULL;
  	gdqp = NULL;
  
  	if (XFS_IS_UQUOTA_ON(mp)) {
  		ASSERT(ip->i_udquot == NULL);
  		/*
  		 * We want the dquot allocated if it doesn't exist.
  		 */
  		if ((error = xfs_qm_dqget(mp, ip, ip->i_d.di_uid, XFS_DQ_USER,
  					 XFS_QMOPT_DQALLOC | XFS_QMOPT_DOWARN,
  					 &udqp))) {
  			/*
  			 * Shouldn't be able to turn off quotas here.
  			 */
  			ASSERT(error != ESRCH);
  			ASSERT(error != ENOENT);
  			return error;
  		}
  		ASSERT(udqp);
  	}
  
  	if (XFS_IS_OQUOTA_ON(mp)) {
  		ASSERT(ip->i_gdquot == NULL);
  		if (udqp)
  			xfs_dqunlock(udqp);
  		error = XFS_IS_GQUOTA_ON(mp) ?
  				xfs_qm_dqget(mp, ip,
  					     ip->i_d.di_gid, XFS_DQ_GROUP,
  					     XFS_QMOPT_DQALLOC|XFS_QMOPT_DOWARN,
  					     &gdqp) :
  				xfs_qm_dqget(mp, ip,
  					     ip->i_d.di_projid, XFS_DQ_PROJ,
  					     XFS_QMOPT_DQALLOC|XFS_QMOPT_DOWARN,
  					     &gdqp);
  		if (error) {
  			if (udqp)
  				xfs_qm_dqrele(udqp);
  			ASSERT(error != ESRCH);
  			ASSERT(error != ENOENT);
  			return error;
  		}
  		ASSERT(gdqp);
  
  		/* Reacquire the locks in the right order */
  		if (udqp) {
  			if (! xfs_qm_dqlock_nowait(udqp)) {
  				xfs_dqunlock(gdqp);
  				xfs_dqlock(udqp);
  				xfs_dqlock(gdqp);
  			}
  		}
  	}
  
  	*O_udqpp = udqp;
  	*O_gdqpp = gdqp;
  
  #ifdef QUOTADEBUG
  	if (udqp) ASSERT(XFS_DQ_IS_LOCKED(udqp));
  	if (gdqp) ASSERT(XFS_DQ_IS_LOCKED(gdqp));
  #endif
  	return 0;
  }
  
  /*
   * Create an inode and return with a reference already taken, but unlocked
   * This is how we create quota inodes
   */
  STATIC int
  xfs_qm_qino_alloc(
  	xfs_mount_t	*mp,
  	xfs_inode_t	**ip,
  	__int64_t	sbfields,
  	uint		flags)
  {
  	xfs_trans_t	*tp;
  	int		error;
  	int		committed;
  
  	tp = xfs_trans_alloc(mp, XFS_TRANS_QM_QINOCREATE);
  	if ((error = xfs_trans_reserve(tp,
  				      XFS_QM_QINOCREATE_SPACE_RES(mp),
  				      XFS_CREATE_LOG_RES(mp), 0,
  				      XFS_TRANS_PERM_LOG_RES,
  				      XFS_CREATE_LOG_COUNT))) {
  		xfs_trans_cancel(tp, 0);
  		return error;
  	}
  
  	if ((error = xfs_dir_ialloc(&tp, NULL, S_IFREG, 1, 0,
  				   &xfs_zerocr, 0, 1, ip, &committed))) {
  		xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES |
  				 XFS_TRANS_ABORT);
  		return error;
  	}
  
  	/*
  	 * Keep an extra reference to this quota inode. This inode is
  	 * locked exclusively and joined to the transaction already.
  	 */
  	ASSERT(xfs_isilocked(*ip, XFS_ILOCK_EXCL));
  	IHOLD(*ip);
  
  	/*
  	 * Make the changes in the superblock, and log those too.
  	 * sbfields arg may contain fields other than *QUOTINO;
  	 * VERSIONNUM for example.
  	 */
  	spin_lock(&mp->m_sb_lock);
  	if (flags & XFS_QMOPT_SBVERSION) {
  #if defined(DEBUG) && defined(XFS_LOUD_RECOVERY)
  		unsigned oldv = mp->m_sb.sb_versionnum;
  #endif
  		ASSERT(!xfs_sb_version_hasquota(&mp->m_sb));
  		ASSERT((sbfields & (XFS_SB_VERSIONNUM | XFS_SB_UQUOTINO |
  				   XFS_SB_GQUOTINO | XFS_SB_QFLAGS)) ==
  		       (XFS_SB_VERSIONNUM | XFS_SB_UQUOTINO |
  			XFS_SB_GQUOTINO | XFS_SB_QFLAGS));
  
  		xfs_sb_version_addquota(&mp->m_sb);
  		mp->m_sb.sb_uquotino = NULLFSINO;
  		mp->m_sb.sb_gquotino = NULLFSINO;
  
  		/* qflags will get updated _after_ quotacheck */
  		mp->m_sb.sb_qflags = 0;
  #if defined(DEBUG) && defined(XFS_LOUD_RECOVERY)
  		cmn_err(CE_NOTE,
  			"Old superblock version %x, converting to %x.",
  			oldv, mp->m_sb.sb_versionnum);
  #endif
  	}
  	if (flags & XFS_QMOPT_UQUOTA)
  		mp->m_sb.sb_uquotino = (*ip)->i_ino;
  	else
  		mp->m_sb.sb_gquotino = (*ip)->i_ino;
  	spin_unlock(&mp->m_sb_lock);
  	xfs_mod_sb(tp, sbfields);
  
  	if ((error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES))) {
  		xfs_fs_cmn_err(CE_ALERT, mp, "XFS qino_alloc failed!");
  		return error;
  	}
  	return 0;
  }
  
  
  STATIC void
  xfs_qm_reset_dqcounts(
  	xfs_mount_t	*mp,
  	xfs_buf_t	*bp,
  	xfs_dqid_t	id,
  	uint		type)
  {
  	xfs_disk_dquot_t	*ddq;
  	int			j;
  
  	trace_xfs_reset_dqcounts(bp, _RET_IP_);
  
  	/*
  	 * Reset all counters and timers. They'll be
  	 * started afresh by xfs_qm_quotacheck.
  	 */
  #ifdef DEBUG
  	j = XFS_FSB_TO_B(mp, XFS_DQUOT_CLUSTER_SIZE_FSB);
  	do_div(j, sizeof(xfs_dqblk_t));
  	ASSERT(XFS_QM_DQPERBLK(mp) == j);
  #endif
  	ddq = (xfs_disk_dquot_t *)XFS_BUF_PTR(bp);
  	for (j = 0; j < XFS_QM_DQPERBLK(mp); j++) {
  		/*
  		 * Do a sanity check, and if needed, repair the dqblk. Don't
  		 * output any warnings because it's perfectly possible to
  		 * find uninitialised dquot blks. See comment in xfs_qm_dqcheck.
  		 */
  		(void) xfs_qm_dqcheck(ddq, id+j, type, XFS_QMOPT_DQREPAIR,
  				      "xfs_quotacheck");
  		ddq->d_bcount = 0;
  		ddq->d_icount = 0;
  		ddq->d_rtbcount = 0;
  		ddq->d_btimer = 0;
  		ddq->d_itimer = 0;
  		ddq->d_rtbtimer = 0;
  		ddq->d_bwarns = 0;
  		ddq->d_iwarns = 0;
  		ddq->d_rtbwarns = 0;
  		ddq = (xfs_disk_dquot_t *) ((xfs_dqblk_t *)ddq + 1);
  	}
  }
  
  STATIC int
  xfs_qm_dqiter_bufs(
  	xfs_mount_t	*mp,
  	xfs_dqid_t	firstid,
  	xfs_fsblock_t	bno,
  	xfs_filblks_t	blkcnt,
  	uint		flags)
  {
  	xfs_buf_t	*bp;
  	int		error;
  	int		notcommitted;
  	int		incr;
  	int		type;
  
  	ASSERT(blkcnt > 0);
  	notcommitted = 0;
  	incr = (blkcnt > XFS_QM_MAX_DQCLUSTER_LOGSZ) ?
  		XFS_QM_MAX_DQCLUSTER_LOGSZ : blkcnt;
  	type = flags & XFS_QMOPT_UQUOTA ? XFS_DQ_USER :
  		(flags & XFS_QMOPT_PQUOTA ? XFS_DQ_PROJ : XFS_DQ_GROUP);
  	error = 0;
  
  	/*
  	 * Blkcnt arg can be a very big number, and might even be
  	 * larger than the log itself. So, we have to break it up into
  	 * manageable-sized transactions.
  	 * Note that we don't start a permanent transaction here; we might
  	 * not be able to get a log reservation for the whole thing up front,
  	 * and we don't really care to either, because we just discard
  	 * everything if we were to crash in the middle of this loop.
  	 */
  	while (blkcnt--) {
  		error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
  			      XFS_FSB_TO_DADDR(mp, bno),
  			      (int)XFS_QI_DQCHUNKLEN(mp), 0, &bp);
  		if (error)
  			break;
  
  		xfs_qm_reset_dqcounts(mp, bp, firstid, type);
  		xfs_bdwrite(mp, bp);
  		/*
  		 * goto the next block.
  		 */
  		bno++;
  		firstid += XFS_QM_DQPERBLK(mp);
  	}
  	return error;
  }
  
  /*
   * Iterate over all allocated USR/GRP/PRJ dquots in the system, calling a
   * caller supplied function for every chunk of dquots that we find.
   */
  STATIC int
  xfs_qm_dqiterate(
  	xfs_mount_t	*mp,
  	xfs_inode_t	*qip,
  	uint		flags)
  {
  	xfs_bmbt_irec_t		*map;
  	int			i, nmaps;	/* number of map entries */
  	int			error;		/* return value */
  	xfs_fileoff_t		lblkno;
  	xfs_filblks_t		maxlblkcnt;
  	xfs_dqid_t		firstid;
  	xfs_fsblock_t		rablkno;
  	xfs_filblks_t		rablkcnt;
  
  	error = 0;
  	/*
  	 * This looks racy, but we can't keep an inode lock across a
  	 * trans_reserve. But, this gets called during quotacheck, and that
  	 * happens only at mount time which is single threaded.
  	 */
  	if (qip->i_d.di_nblocks == 0)
  		return 0;
  
  	map = kmem_alloc(XFS_DQITER_MAP_SIZE * sizeof(*map), KM_SLEEP);
  
  	lblkno = 0;
  	maxlblkcnt = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
  	do {
  		nmaps = XFS_DQITER_MAP_SIZE;
  		/*
  		 * We aren't changing the inode itself. Just changing
  		 * some of its data. No new blocks are added here, and
  		 * the inode is never added to the transaction.
  		 */
  		xfs_ilock(qip, XFS_ILOCK_SHARED);
  		error = xfs_bmapi(NULL, qip, lblkno,
  				  maxlblkcnt - lblkno,
  				  XFS_BMAPI_METADATA,
  				  NULL,
  				  0, map, &nmaps, NULL, NULL);
  		xfs_iunlock(qip, XFS_ILOCK_SHARED);
  		if (error)
  			break;
  
  		ASSERT(nmaps <= XFS_DQITER_MAP_SIZE);
  		for (i = 0; i < nmaps; i++) {
  			ASSERT(map[i].br_startblock != DELAYSTARTBLOCK);
  			ASSERT(map[i].br_blockcount);
  
  
  			lblkno += map[i].br_blockcount;
  
  			if (map[i].br_startblock == HOLESTARTBLOCK)
  				continue;
  
  			firstid = (xfs_dqid_t) map[i].br_startoff *
  				XFS_QM_DQPERBLK(mp);
  			/*
  			 * Do a read-ahead on the next extent.
  			 */
  			if ((i+1 < nmaps) &&
  			    (map[i+1].br_startblock != HOLESTARTBLOCK)) {
  				rablkcnt =  map[i+1].br_blockcount;
  				rablkno = map[i+1].br_startblock;
  				while (rablkcnt--) {
  					xfs_baread(mp->m_ddev_targp,
  					       XFS_FSB_TO_DADDR(mp, rablkno),
  					       (int)XFS_QI_DQCHUNKLEN(mp));
  					rablkno++;
  				}
  			}
  			/*
  			 * Iterate thru all the blks in the extent and
  			 * reset the counters of all the dquots inside them.
  			 */
  			if ((error = xfs_qm_dqiter_bufs(mp,
  						       firstid,
  						       map[i].br_startblock,
  						       map[i].br_blockcount,
  						       flags))) {
  				break;
  			}
  		}
  
  		if (error)
  			break;
  	} while (nmaps > 0);
  
  	kmem_free(map);
  
  	return error;
  }
  
  /*
   * Called by dqusage_adjust in doing a quotacheck.
   * Given the inode, and a dquot (either USR or GRP, doesn't matter),
   * this updates its incore copy as well as the buffer copy. This is
   * so that once the quotacheck is done, we can just log all the buffers,
   * as opposed to logging numerous updates to individual dquots.
   */
  STATIC void
  xfs_qm_quotacheck_dqadjust(
  	xfs_dquot_t		*dqp,
  	xfs_qcnt_t		nblks,
  	xfs_qcnt_t		rtblks)
  {
  	ASSERT(XFS_DQ_IS_LOCKED(dqp));
  
  	trace_xfs_dqadjust(dqp);
  
  	/*
  	 * Adjust the inode count and the block count to reflect this inode's
  	 * resource usage.
  	 */
  	be64_add_cpu(&dqp->q_core.d_icount, 1);
  	dqp->q_res_icount++;
  	if (nblks) {
  		be64_add_cpu(&dqp->q_core.d_bcount, nblks);
  		dqp->q_res_bcount += nblks;
  	}
  	if (rtblks) {
  		be64_add_cpu(&dqp->q_core.d_rtbcount, rtblks);
  		dqp->q_res_rtbcount += rtblks;
  	}
  
  	/*
  	 * Set default limits, adjust timers (since we changed usages)
  	 */
  	if (! XFS_IS_SUSER_DQUOT(dqp)) {
  		xfs_qm_adjust_dqlimits(dqp->q_mount, &dqp->q_core);
  		xfs_qm_adjust_dqtimers(dqp->q_mount, &dqp->q_core);
  	}
  
  	dqp->dq_flags |= XFS_DQ_DIRTY;
  }
  
  STATIC int
  xfs_qm_get_rtblks(
  	xfs_inode_t	*ip,
  	xfs_qcnt_t	*O_rtblks)
  {
  	xfs_filblks_t	rtblks;			/* total rt blks */
  	xfs_extnum_t	idx;			/* extent record index */
  	xfs_ifork_t	*ifp;			/* inode fork pointer */
  	xfs_extnum_t	nextents;		/* number of extent entries */
  	int		error;
  
  	ASSERT(XFS_IS_REALTIME_INODE(ip));
  	ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
  	if (!(ifp->if_flags & XFS_IFEXTENTS)) {
  		if ((error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK)))
  			return error;
  	}
  	rtblks = 0;
  	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
  	for (idx = 0; idx < nextents; idx++)
  		rtblks += xfs_bmbt_get_blockcount(xfs_iext_get_ext(ifp, idx));
  	*O_rtblks = (xfs_qcnt_t)rtblks;
  	return 0;
  }
  
  /*
   * callback routine supplied to bulkstat(). Given an inumber, find its
   * dquots and update them to account for resources taken by that inode.
   */
  /* ARGSUSED */
  STATIC int
  xfs_qm_dqusage_adjust(
  	xfs_mount_t	*mp,		/* mount point for filesystem */
  	xfs_ino_t	ino,		/* inode number to get data for */
  	void		__user *buffer,	/* not used */
  	int		ubsize,		/* not used */
  	void		*private_data,	/* not used */
  	xfs_daddr_t	bno,		/* starting block of inode cluster */
  	int		*ubused,	/* not used */
  	void		*dip,		/* on-disk inode pointer (not used) */
  	int		*res)		/* result code value */
  {
  	xfs_inode_t	*ip;
  	xfs_dquot_t	*udqp, *gdqp;
  	xfs_qcnt_t	nblks, rtblks;
  	int		error;
  
  	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
  
  	/*
  	 * rootino must have its resources accounted for, not so with the quota
  	 * inodes.
  	 */
  	if (ino == mp->m_sb.sb_uquotino || ino == mp->m_sb.sb_gquotino) {
  		*res = BULKSTAT_RV_NOTHING;
  		return XFS_ERROR(EINVAL);
  	}
  
  	/*
  	 * We don't _need_ to take the ilock EXCL. However, the xfs_qm_dqget
  	 * interface expects the inode to be exclusively locked because that's
  	 * the case in all other instances. It's OK that we do this because
  	 * quotacheck is done only at mount time.
  	 */
  	if ((error = xfs_iget(mp, NULL, ino, 0, XFS_ILOCK_EXCL, &ip, bno))) {
  		*res = BULKSTAT_RV_NOTHING;
  		return error;
  	}
  
  	/*
  	 * Obtain the locked dquots. In case of an error (eg. allocation
  	 * fails for ENOSPC), we return the negative of the error number
  	 * to bulkstat, so that it can get propagated to quotacheck() and
  	 * making us disable quotas for the file system.
  	 */
  	if ((error = xfs_qm_dqget_noattach(ip, &udqp, &gdqp))) {
  		xfs_iput(ip, XFS_ILOCK_EXCL);
  		*res = BULKSTAT_RV_GIVEUP;
  		return error;
  	}
  
  	rtblks = 0;
  	if (! XFS_IS_REALTIME_INODE(ip)) {
  		nblks = (xfs_qcnt_t)ip->i_d.di_nblocks;
  	} else {
  		/*
  		 * Walk thru the extent list and count the realtime blocks.
  		 */
  		if ((error = xfs_qm_get_rtblks(ip, &rtblks))) {
  			xfs_iput(ip, XFS_ILOCK_EXCL);
  			if (udqp)
  				xfs_qm_dqput(udqp);
  			if (gdqp)
  				xfs_qm_dqput(gdqp);
  			*res = BULKSTAT_RV_GIVEUP;
  			return error;
  		}
  		nblks = (xfs_qcnt_t)ip->i_d.di_nblocks - rtblks;
  	}
  	ASSERT(ip->i_delayed_blks == 0);
  
  	/*
  	 * We can't release the inode while holding its dquot locks.
  	 * The inode can go into inactive and might try to acquire the dquotlocks.
  	 * So, just unlock here and do a vn_rele at the end.
  	 */
  	xfs_iunlock(ip, XFS_ILOCK_EXCL);
  
  	/*
  	 * Add the (disk blocks and inode) resources occupied by this
  	 * inode to its dquots. We do this adjustment in the incore dquot,
  	 * and also copy the changes to its buffer.
  	 * We don't care about putting these changes in a transaction
  	 * envelope because if we crash in the middle of a 'quotacheck'
  	 * we have to start from the beginning anyway.
  	 * Once we're done, we'll log all the dquot bufs.
  	 *
  	 * The *QUOTA_ON checks below may look pretty racy, but quotachecks
  	 * and quotaoffs don't race. (Quotachecks happen at mount time only).
  	 */
  	if (XFS_IS_UQUOTA_ON(mp)) {
  		ASSERT(udqp);
  		xfs_qm_quotacheck_dqadjust(udqp, nblks, rtblks);
  		xfs_qm_dqput(udqp);
  	}
  	if (XFS_IS_OQUOTA_ON(mp)) {
  		ASSERT(gdqp);
  		xfs_qm_quotacheck_dqadjust(gdqp, nblks, rtblks);
  		xfs_qm_dqput(gdqp);
  	}
  	/*
  	 * Now release the inode. This will send it to 'inactive', and
  	 * possibly even free blocks.
  	 */
  	IRELE(ip);
  
  	/*
  	 * Goto next inode.
  	 */
  	*res = BULKSTAT_RV_DIDONE;
  	return 0;
  }
  
  /*
   * Walk thru all the filesystem inodes and construct a consistent view
   * of the disk quota world. If the quotacheck fails, disable quotas.
   */
  int
  xfs_qm_quotacheck(
  	xfs_mount_t	*mp)
  {
  	int		done, count, error;
  	xfs_ino_t	lastino;
  	size_t		structsz;
  	xfs_inode_t	*uip, *gip;
  	uint		flags;
  
  	count = INT_MAX;
  	structsz = 1;
  	lastino = 0;
  	flags = 0;
  
  	ASSERT(XFS_QI_UQIP(mp) || XFS_QI_GQIP(mp));
  	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
  
  	/*
  	 * There should be no cached dquots. The (simplistic) quotacheck
  	 * algorithm doesn't like that.
  	 */
  	ASSERT(XFS_QI_MPLNDQUOTS(mp) == 0);
  
  	cmn_err(CE_NOTE, "XFS quotacheck %s: Please wait.", mp->m_fsname);
  
  	/*
  	 * First we go thru all the dquots on disk, USR and GRP/PRJ, and reset
  	 * their counters to zero. We need a clean slate.
  	 * We don't log our changes till later.
  	 */
  	if ((uip = XFS_QI_UQIP(mp))) {
  		if ((error = xfs_qm_dqiterate(mp, uip, XFS_QMOPT_UQUOTA)))
  			goto error_return;
  		flags |= XFS_UQUOTA_CHKD;
  	}
  
  	if ((gip = XFS_QI_GQIP(mp))) {
  		if ((error = xfs_qm_dqiterate(mp, gip, XFS_IS_GQUOTA_ON(mp) ?
  					XFS_QMOPT_GQUOTA : XFS_QMOPT_PQUOTA)))
  			goto error_return;
  		flags |= XFS_OQUOTA_CHKD;
  	}
  
  	do {
  		/*
  		 * Iterate thru all the inodes in the file system,
  		 * adjusting the corresponding dquot counters in core.
  		 */
  		if ((error = xfs_bulkstat(mp, &lastino, &count,
  				     xfs_qm_dqusage_adjust, NULL,
  				     structsz, NULL, BULKSTAT_FG_IGET, &done)))
  			break;
  
  	} while (! done);
  
  	/*
  	 * We've made all the changes that we need to make incore.
  	 * Flush them down to disk buffers if everything was updated
  	 * successfully.
  	 */
  	if (!error)
  		error = xfs_qm_dqflush_all(mp, XFS_QMOPT_DELWRI);
  
  	/*
  	 * We can get this error if we couldn't do a dquot allocation inside
  	 * xfs_qm_dqusage_adjust (via bulkstat). We don't care about the
  	 * dirty dquots that might be cached, we just want to get rid of them
  	 * and turn quotaoff. The dquots won't be attached to any of the inodes
  	 * at this point (because we intentionally didn't in dqget_noattach).
  	 */
  	if (error) {
  		xfs_qm_dqpurge_all(mp, XFS_QMOPT_QUOTALL | XFS_QMOPT_QUOTAOFF);
  		goto error_return;
  	}
  
  	/*
  	 * We didn't log anything, because if we crashed, we'll have to
  	 * start the quotacheck from scratch anyway. However, we must make
  	 * sure that our dquot changes are secure before we put the
  	 * quotacheck'd stamp on the superblock. So, here we do a synchronous
  	 * flush.
  	 */
  	XFS_bflush(mp->m_ddev_targp);
  
  	/*
  	 * If one type of quotas is off, then it will lose its
  	 * quotachecked status, since we won't be doing accounting for
  	 * that type anymore.
  	 */
  	mp->m_qflags &= ~(XFS_OQUOTA_CHKD | XFS_UQUOTA_CHKD);
  	mp->m_qflags |= flags;
  
  	XQM_LIST_PRINT(&(XFS_QI_MPL_LIST(mp)), MPL_NEXT, "++++ Mp list +++");
  
   error_return:
  	if (error) {
  		cmn_err(CE_WARN, "XFS quotacheck %s: Unsuccessful (Error %d): "
  			"Disabling quotas.",
  			mp->m_fsname, error);
  		/*
  		 * We must turn off quotas.
  		 */
  		ASSERT(mp->m_quotainfo != NULL);
  		ASSERT(xfs_Gqm != NULL);
  		xfs_qm_destroy_quotainfo(mp);
  		if (xfs_mount_reset_sbqflags(mp)) {
  			cmn_err(CE_WARN, "XFS quotacheck %s: "
  				"Failed to reset quota flags.", mp->m_fsname);
  		}
  	} else {
  		cmn_err(CE_NOTE, "XFS quotacheck %s: Done.", mp->m_fsname);
  	}
  	return (error);
  }
  
  /*
   * This is called after the superblock has been read in and we're ready to
   * iget the quota inodes.
   */
  STATIC int
  xfs_qm_init_quotainos(
  	xfs_mount_t	*mp)
  {
  	xfs_inode_t	*uip, *gip;
  	int		error;
  	__int64_t	sbflags;
  	uint		flags;
  
  	ASSERT(mp->m_quotainfo);
  	uip = gip = NULL;
  	sbflags = 0;
  	flags = 0;
  
  	/*
  	 * Get the uquota and gquota inodes
  	 */
  	if (xfs_sb_version_hasquota(&mp->m_sb)) {
  		if (XFS_IS_UQUOTA_ON(mp) &&
  		    mp->m_sb.sb_uquotino != NULLFSINO) {
  			ASSERT(mp->m_sb.sb_uquotino > 0);
  			if ((error = xfs_iget(mp, NULL, mp->m_sb.sb_uquotino,
  					     0, 0, &uip, 0)))
  				return XFS_ERROR(error);
  		}
  		if (XFS_IS_OQUOTA_ON(mp) &&
  		    mp->m_sb.sb_gquotino != NULLFSINO) {
  			ASSERT(mp->m_sb.sb_gquotino > 0);
  			if ((error = xfs_iget(mp, NULL, mp->m_sb.sb_gquotino,
  					     0, 0, &gip, 0))) {
  				if (uip)
  					IRELE(uip);
  				return XFS_ERROR(error);
  			}
  		}
  	} else {
  		flags |= XFS_QMOPT_SBVERSION;
  		sbflags |= (XFS_SB_VERSIONNUM | XFS_SB_UQUOTINO |
  			    XFS_SB_GQUOTINO | XFS_SB_QFLAGS);
  	}
  
  	/*
  	 * Create the two inodes, if they don't exist already. The changes
  	 * made above will get added to a transaction and logged in one of
  	 * the qino_alloc calls below.  If the device is readonly,
  	 * temporarily switch to read-write to do this.
  	 */
  	if (XFS_IS_UQUOTA_ON(mp) && uip == NULL) {
  		if ((error = xfs_qm_qino_alloc(mp, &uip,
  					      sbflags | XFS_SB_UQUOTINO,
  					      flags | XFS_QMOPT_UQUOTA)))
  			return XFS_ERROR(error);
  
  		flags &= ~XFS_QMOPT_SBVERSION;
  	}
  	if (XFS_IS_OQUOTA_ON(mp) && gip == NULL) {
  		flags |= (XFS_IS_GQUOTA_ON(mp) ?
  				XFS_QMOPT_GQUOTA : XFS_QMOPT_PQUOTA);
  		error = xfs_qm_qino_alloc(mp, &gip,
  					  sbflags | XFS_SB_GQUOTINO, flags);
  		if (error) {
  			if (uip)
  				IRELE(uip);
  
  			return XFS_ERROR(error);
  		}
  	}
  
  	XFS_QI_UQIP(mp) = uip;
  	XFS_QI_GQIP(mp) = gip;
  
  	return 0;
  }
  
  
  /*
   * Traverse the freelist of dquots and attempt to reclaim a maximum of
   * 'howmany' dquots. This operation races with dqlookup(), and attempts to
   * favor the lookup function ...
   * XXXsup merge this with qm_reclaim_one().
   */
  STATIC int
  xfs_qm_shake_freelist(
  	int howmany)
  {
  	int		nreclaimed;
  	xfs_dqhash_t	*hash;
  	xfs_dquot_t	*dqp, *nextdqp;
  	int		restarts;
  	int		nflushes;
  
  	if (howmany <= 0)
  		return 0;
  
  	nreclaimed = 0;
  	restarts = 0;
  	nflushes = 0;
  
  #ifdef QUOTADEBUG
  	cmn_err(CE_DEBUG, "Shake free 0x%x", howmany);
  #endif
  	/* lock order is : hashchainlock, freelistlock, mplistlock */
   tryagain:
  	xfs_qm_freelist_lock(xfs_Gqm);
  
  	for (dqp = xfs_Gqm->qm_dqfreelist.qh_next;
  	     ((dqp != (xfs_dquot_t *) &xfs_Gqm->qm_dqfreelist) &&
  	      nreclaimed < howmany); ) {
  		xfs_dqlock(dqp);
  
  		/*
  		 * We are racing with dqlookup here. Naturally we don't
  		 * want to reclaim a dquot that lookup wants.
  		 */
  		if (dqp->dq_flags & XFS_DQ_WANT) {
  			xfs_dqunlock(dqp);
  			xfs_qm_freelist_unlock(xfs_Gqm);
  			if (++restarts >= XFS_QM_RECLAIM_MAX_RESTARTS)
  				return nreclaimed;
  			XQM_STATS_INC(xqmstats.xs_qm_dqwants);
  			goto tryagain;
  		}
  
  		/*
  		 * If the dquot is inactive, we are assured that it is
  		 * not on the mplist or the hashlist, and that makes our
  		 * life easier.
  		 */
  		if (dqp->dq_flags & XFS_DQ_INACTIVE) {
  			ASSERT(dqp->q_mount == NULL);
  			ASSERT(! XFS_DQ_IS_DIRTY(dqp));
  			ASSERT(dqp->HL_PREVP == NULL);
  			ASSERT(dqp->MPL_PREVP == NULL);
  			XQM_STATS_INC(xqmstats.xs_qm_dqinact_reclaims);
  			nextdqp = dqp->dq_flnext;
  			goto off_freelist;
  		}
  
  		ASSERT(dqp->MPL_PREVP);
  		/*
  		 * Try to grab the flush lock. If this dquot is in the process of
  		 * getting flushed to disk, we don't want to reclaim it.
  		 */
  		if (!xfs_dqflock_nowait(dqp)) {
  			xfs_dqunlock(dqp);
  			dqp = dqp->dq_flnext;
  			continue;
  		}
  
  		/*
  		 * We have the flush lock so we know that this is not in the
  		 * process of being flushed. So, if this is dirty, flush it
  		 * DELWRI so that we don't get a freelist infested with
  		 * dirty dquots.
  		 */
  		if (XFS_DQ_IS_DIRTY(dqp)) {
  			int	error;
  
  			trace_xfs_dqshake_dirty(dqp);
  
  			/*
  			 * We flush it delayed write, so don't bother
  			 * releasing the mplock.
  			 */
  			error = xfs_qm_dqflush(dqp, XFS_QMOPT_DELWRI);
  			if (error) {
  				xfs_fs_cmn_err(CE_WARN, dqp->q_mount,
  			"xfs_qm_dqflush_all: dquot %p flush failed", dqp);
  			}
  			xfs_dqunlock(dqp); /* dqflush unlocks dqflock */
  			dqp = dqp->dq_flnext;
  			continue;
  		}
  		/*
  		 * We're trying to get the hashlock out of order. This races
  		 * with dqlookup; so, we giveup and goto the next dquot if
  		 * we couldn't get the hashlock. This way, we won't starve
  		 * a dqlookup process that holds the hashlock that is
  		 * waiting for the freelist lock.
  		 */
  		if (!mutex_trylock(&dqp->q_hash->qh_lock)) {
  			xfs_dqfunlock(dqp);
  			xfs_dqunlock(dqp);
  			dqp = dqp->dq_flnext;
  			continue;
  		}
  		/*
  		 * This races with dquot allocation code as well as dqflush_all
  		 * and reclaim code. So, if we failed to grab the mplist lock,
  		 * giveup everything and start over.
  		 */
  		hash = dqp->q_hash;
  		ASSERT(hash);
  		if (! xfs_qm_mplist_nowait(dqp->q_mount)) {
  			/* XXX put a sentinel so that we can come back here */
  			xfs_dqfunlock(dqp);
  			xfs_dqunlock(dqp);
  			mutex_unlock(&hash->qh_lock);
  			xfs_qm_freelist_unlock(xfs_Gqm);
  			if (++restarts >= XFS_QM_RECLAIM_MAX_RESTARTS)
  				return nreclaimed;
  			goto tryagain;
  		}
  
  		trace_xfs_dqshake_unlink(dqp);
  
  #ifdef QUOTADEBUG
  		cmn_err(CE_DEBUG, "Shake 0x%p, ID 0x%x\n",
  			dqp, be32_to_cpu(dqp->q_core.d_id));
  #endif
  		ASSERT(dqp->q_nrefs == 0);
  		nextdqp = dqp->dq_flnext;
  		XQM_MPLIST_REMOVE(&(XFS_QI_MPL_LIST(dqp->q_mount)), dqp);
  		XQM_HASHLIST_REMOVE(hash, dqp);
  		xfs_dqfunlock(dqp);
  		xfs_qm_mplist_unlock(dqp->q_mount);
  		mutex_unlock(&hash->qh_lock);
  
   off_freelist:
  		XQM_FREELIST_REMOVE(dqp);
  		xfs_dqunlock(dqp);
  		nreclaimed++;
  		XQM_STATS_INC(xqmstats.xs_qm_dqshake_reclaims);
  		xfs_qm_dqdestroy(dqp);
  		dqp = nextdqp;
  	}
  	xfs_qm_freelist_unlock(xfs_Gqm);
  	return nreclaimed;
  }
  
  
  /*
   * The kmem_shake interface is invoked when memory is running low.
   */
  /* ARGSUSED */
  STATIC int
  xfs_qm_shake(int nr_to_scan, gfp_t gfp_mask)
  {
  	int	ndqused, nfree, n;
  
  	if (!kmem_shake_allow(gfp_mask))
  		return 0;
  	if (!xfs_Gqm)
  		return 0;
  
  	nfree = xfs_Gqm->qm_dqfreelist.qh_nelems; /* free dquots */
  	/* incore dquots in all f/s's */
  	ndqused = atomic_read(&xfs_Gqm->qm_totaldquots) - nfree;
  
  	ASSERT(ndqused >= 0);
  
  	if (nfree <= ndqused && nfree < ndquot)
  		return 0;
  
  	ndqused *= xfs_Gqm->qm_dqfree_ratio;	/* target # of free dquots */
  	n = nfree - ndqused - ndquot;		/* # over target */
  
  	return xfs_qm_shake_freelist(MAX(nfree, n));
  }
  
  
  /*
   * Just pop the least recently used dquot off the freelist and
   * recycle it. The returned dquot is locked.
   */
  STATIC xfs_dquot_t *
  xfs_qm_dqreclaim_one(void)
  {
  	xfs_dquot_t	*dqpout;
  	xfs_dquot_t	*dqp;
  	int		restarts;
  	int		nflushes;
  
  	restarts = 0;
  	dqpout = NULL;
  	nflushes = 0;
  
  	/* lockorder: hashchainlock, freelistlock, mplistlock, dqlock, dqflock */
   startagain:
  	xfs_qm_freelist_lock(xfs_Gqm);
  
  	FOREACH_DQUOT_IN_FREELIST(dqp, &(xfs_Gqm->qm_dqfreelist)) {
  		xfs_dqlock(dqp);
  
  		/*
  		 * We are racing with dqlookup here. Naturally we don't
  		 * want to reclaim a dquot that lookup wants. We release the
  		 * freelist lock and start over, so that lookup will grab
  		 * both the dquot and the freelistlock.
  		 */
  		if (dqp->dq_flags & XFS_DQ_WANT) {
  			ASSERT(! (dqp->dq_flags & XFS_DQ_INACTIVE));
  
  			trace_xfs_dqreclaim_want(dqp);
  
  			xfs_dqunlock(dqp);
  			xfs_qm_freelist_unlock(xfs_Gqm);
  			if (++restarts >= XFS_QM_RECLAIM_MAX_RESTARTS)
  				return NULL;
  			XQM_STATS_INC(xqmstats.xs_qm_dqwants);
  			goto startagain;
  		}
  
  		/*
  		 * If the dquot is inactive, we are assured that it is
  		 * not on the mplist or the hashlist, and that makes our
  		 * life easier.
  		 */
  		if (dqp->dq_flags & XFS_DQ_INACTIVE) {
  			ASSERT(dqp->q_mount == NULL);
  			ASSERT(! XFS_DQ_IS_DIRTY(dqp));
  			ASSERT(dqp->HL_PREVP == NULL);
  			ASSERT(dqp->MPL_PREVP == NULL);
  			XQM_FREELIST_REMOVE(dqp);
  			xfs_dqunlock(dqp);
  			dqpout = dqp;
  			XQM_STATS_INC(xqmstats.xs_qm_dqinact_reclaims);
  			break;
  		}
  
  		ASSERT(dqp->q_hash);
  		ASSERT(dqp->MPL_PREVP);
  
  		/*
  		 * Try to grab the flush lock. If this dquot is in the process of
  		 * getting flushed to disk, we don't want to reclaim it.
  		 */
  		if (!xfs_dqflock_nowait(dqp)) {
  			xfs_dqunlock(dqp);
  			continue;
  		}
  
  		/*
  		 * We have the flush lock so we know that this is not in the
  		 * process of being flushed. So, if this is dirty, flush it
  		 * DELWRI so that we don't get a freelist infested with
  		 * dirty dquots.
  		 */
  		if (XFS_DQ_IS_DIRTY(dqp)) {
  			int	error;
  
  			trace_xfs_dqreclaim_dirty(dqp);
  
  			/*
  			 * We flush it delayed write, so don't bother
  			 * releasing the freelist lock.
  			 */
  			error = xfs_qm_dqflush(dqp, XFS_QMOPT_DELWRI);
  			if (error) {
  				xfs_fs_cmn_err(CE_WARN, dqp->q_mount,
  			"xfs_qm_dqreclaim: dquot %p flush failed", dqp);
  			}
  			xfs_dqunlock(dqp); /* dqflush unlocks dqflock */
  			continue;
  		}
  
  		if (! xfs_qm_mplist_nowait(dqp->q_mount)) {
  			xfs_dqfunlock(dqp);
  			xfs_dqunlock(dqp);
  			continue;
  		}
  
  		if (!mutex_trylock(&dqp->q_hash->qh_lock))
  			goto mplistunlock;
  
  		trace_xfs_dqreclaim_unlink(dqp);
  
  		ASSERT(dqp->q_nrefs == 0);
  		XQM_MPLIST_REMOVE(&(XFS_QI_MPL_LIST(dqp->q_mount)), dqp);
  		XQM_HASHLIST_REMOVE(dqp->q_hash, dqp);
  		XQM_FREELIST_REMOVE(dqp);
  		dqpout = dqp;
  		mutex_unlock(&dqp->q_hash->qh_lock);
   mplistunlock:
  		xfs_qm_mplist_unlock(dqp->q_mount);
  		xfs_dqfunlock(dqp);
  		xfs_dqunlock(dqp);
  		if (dqpout)
  			break;
  	}
  
  	xfs_qm_freelist_unlock(xfs_Gqm);
  	return dqpout;
  }
  
  
  /*------------------------------------------------------------------*/
  
  /*
   * Return a new incore dquot. Depending on the number of
   * dquots in the system, we either allocate a new one on the kernel heap,
   * or reclaim a free one.
   * Return value is B_TRUE if we allocated a new dquot, B_FALSE if we managed
   * to reclaim an existing one from the freelist.
   */
  boolean_t
  xfs_qm_dqalloc_incore(
  	xfs_dquot_t **O_dqpp)
  {
  	xfs_dquot_t	*dqp;
  
  	/*
  	 * Check against high water mark to see if we want to pop
  	 * a nincompoop dquot off the freelist.
  	 */
  	if (atomic_read(&xfs_Gqm->qm_totaldquots) >= ndquot) {
  		/*
  		 * Try to recycle a dquot from the freelist.
  		 */
  		if ((dqp = xfs_qm_dqreclaim_one())) {
  			XQM_STATS_INC(xqmstats.xs_qm_dqreclaims);
  			/*
  			 * Just zero the core here. The rest will get
  			 * reinitialized by caller. XXX we shouldn't even
  			 * do this zero ...
  			 */
  			memset(&dqp->q_core, 0, sizeof(dqp->q_core));
  			*O_dqpp = dqp;
  			return B_FALSE;
  		}
  		XQM_STATS_INC(xqmstats.xs_qm_dqreclaim_misses);
  	}
  
  	/*
  	 * Allocate a brand new dquot on the kernel heap and return it
  	 * to the caller to initialize.
  	 */
  	ASSERT(xfs_Gqm->qm_dqzone != NULL);
  	*O_dqpp = kmem_zone_zalloc(xfs_Gqm->qm_dqzone, KM_SLEEP);
  	atomic_inc(&xfs_Gqm->qm_totaldquots);
  
  	return B_TRUE;
  }
  
  
  /*
   * Start a transaction and write the incore superblock changes to
   * disk. flags parameter indicates which fields have changed.
   */
  int
  xfs_qm_write_sb_changes(
  	xfs_mount_t	*mp,
  	__int64_t	flags)
  {
  	xfs_trans_t	*tp;
  	int		error;
  
  #ifdef QUOTADEBUG
  	cmn_err(CE_NOTE, "Writing superblock quota changes :%s", mp->m_fsname);
  #endif
  	tp = xfs_trans_alloc(mp, XFS_TRANS_QM_SBCHANGE);
  	if ((error = xfs_trans_reserve(tp, 0,
  				      mp->m_sb.sb_sectsize + 128, 0,
  				      0,
  				      XFS_DEFAULT_LOG_COUNT))) {
  		xfs_trans_cancel(tp, 0);
  		return error;
  	}
  
  	xfs_mod_sb(tp, flags);
  	error = xfs_trans_commit(tp, 0);
  
  	return error;
  }
  
  
  /* --------------- utility functions for vnodeops ---------------- */
  
  
  /*
   * Given an inode, a uid and gid (from cred_t) make sure that we have
   * allocated relevant dquot(s) on disk, and that we won't exceed inode
   * quotas by creating this file.
   * This also attaches dquot(s) to the given inode after locking it,
   * and returns the dquots corresponding to the uid and/or gid.
   *
   * in	: inode (unlocked)
   * out	: udquot, gdquot with references taken and unlocked
   */
  int
  xfs_qm_vop_dqalloc(
  	struct xfs_inode	*ip,
  	uid_t			uid,
  	gid_t			gid,
  	prid_t			prid,
  	uint			flags,
  	struct xfs_dquot	**O_udqpp,
  	struct xfs_dquot	**O_gdqpp)
  {
  	struct xfs_mount	*mp = ip->i_mount;
  	struct xfs_dquot	*uq, *gq;
  	int			error;
  	uint			lockflags;
  
  	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
  		return 0;
  
  	lockflags = XFS_ILOCK_EXCL;
  	xfs_ilock(ip, lockflags);
  
  	if ((flags & XFS_QMOPT_INHERIT) && XFS_INHERIT_GID(ip))
  		gid = ip->i_d.di_gid;
  
  	/*
  	 * Attach the dquot(s) to this inode, doing a dquot allocation
  	 * if necessary. The dquot(s) will not be locked.
  	 */
  	if (XFS_NOT_DQATTACHED(mp, ip)) {
  		error = xfs_qm_dqattach_locked(ip, XFS_QMOPT_DQALLOC);
  		if (error) {
  			xfs_iunlock(ip, lockflags);
  			return error;
  		}
  	}
  
  	uq = gq = NULL;
  	if ((flags & XFS_QMOPT_UQUOTA) && XFS_IS_UQUOTA_ON(mp)) {
  		if (ip->i_d.di_uid != uid) {
  			/*
  			 * What we need is the dquot that has this uid, and
  			 * if we send the inode to dqget, the uid of the inode
  			 * takes priority over what's sent in the uid argument.
  			 * We must unlock inode here before calling dqget if
  			 * we're not sending the inode, because otherwise
  			 * we'll deadlock by doing trans_reserve while
  			 * holding ilock.
  			 */
  			xfs_iunlock(ip, lockflags);
  			if ((error = xfs_qm_dqget(mp, NULL, (xfs_dqid_t) uid,
  						 XFS_DQ_USER,
  						 XFS_QMOPT_DQALLOC |
  						 XFS_QMOPT_DOWARN,
  						 &uq))) {
  				ASSERT(error != ENOENT);
  				return error;
  			}
  			/*
  			 * Get the ilock in the right order.
  			 */
  			xfs_dqunlock(uq);
  			lockflags = XFS_ILOCK_SHARED;
  			xfs_ilock(ip, lockflags);
  		} else {
  			/*
  			 * Take an extra reference, because we'll return
  			 * this to caller
  			 */
  			ASSERT(ip->i_udquot);
  			uq = ip->i_udquot;
  			xfs_dqlock(uq);
  			XFS_DQHOLD(uq);
  			xfs_dqunlock(uq);
  		}
  	}
  	if ((flags & XFS_QMOPT_GQUOTA) && XFS_IS_GQUOTA_ON(mp)) {
  		if (ip->i_d.di_gid != gid) {
  			xfs_iunlock(ip, lockflags);
  			if ((error = xfs_qm_dqget(mp, NULL, (xfs_dqid_t)gid,
  						 XFS_DQ_GROUP,
  						 XFS_QMOPT_DQALLOC |
  						 XFS_QMOPT_DOWARN,
  						 &gq))) {
  				if (uq)
  					xfs_qm_dqrele(uq);
  				ASSERT(error != ENOENT);
  				return error;
  			}
  			xfs_dqunlock(gq);
  			lockflags = XFS_ILOCK_SHARED;
  			xfs_ilock(ip, lockflags);
  		} else {
  			ASSERT(ip->i_gdquot);
  			gq = ip->i_gdquot;
  			xfs_dqlock(gq);
  			XFS_DQHOLD(gq);
  			xfs_dqunlock(gq);
  		}
  	} else if ((flags & XFS_QMOPT_PQUOTA) && XFS_IS_PQUOTA_ON(mp)) {
  		if (ip->i_d.di_projid != prid) {
  			xfs_iunlock(ip, lockflags);
  			if ((error = xfs_qm_dqget(mp, NULL, (xfs_dqid_t)prid,
  						 XFS_DQ_PROJ,
  						 XFS_QMOPT_DQALLOC |
  						 XFS_QMOPT_DOWARN,
  						 &gq))) {
  				if (uq)
  					xfs_qm_dqrele(uq);
  				ASSERT(error != ENOENT);
  				return (error);
  			}
  			xfs_dqunlock(gq);
  			lockflags = XFS_ILOCK_SHARED;
  			xfs_ilock(ip, lockflags);
  		} else {
  			ASSERT(ip->i_gdquot);
  			gq = ip->i_gdquot;
  			xfs_dqlock(gq);
  			XFS_DQHOLD(gq);
  			xfs_dqunlock(gq);
  		}
  	}
  	if (uq)
  		trace_xfs_dquot_dqalloc(ip);
  
  	xfs_iunlock(ip, lockflags);
  	if (O_udqpp)
  		*O_udqpp = uq;
  	else if (uq)
  		xfs_qm_dqrele(uq);
  	if (O_gdqpp)
  		*O_gdqpp = gq;
  	else if (gq)
  		xfs_qm_dqrele(gq);
  	return 0;
  }
  
  /*
   * Actually transfer ownership, and do dquot modifications.
   * These were already reserved.
   */
  xfs_dquot_t *
  xfs_qm_vop_chown(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*ip,
  	xfs_dquot_t	**IO_olddq,
  	xfs_dquot_t	*newdq)
  {
  	xfs_dquot_t	*prevdq;
  	uint		bfield = XFS_IS_REALTIME_INODE(ip) ?
  				 XFS_TRANS_DQ_RTBCOUNT : XFS_TRANS_DQ_BCOUNT;
  
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
  	ASSERT(XFS_IS_QUOTA_RUNNING(ip->i_mount));
  
  	/* old dquot */
  	prevdq = *IO_olddq;
  	ASSERT(prevdq);
  	ASSERT(prevdq != newdq);
  
  	xfs_trans_mod_dquot(tp, prevdq, bfield, -(ip->i_d.di_nblocks));
  	xfs_trans_mod_dquot(tp, prevdq, XFS_TRANS_DQ_ICOUNT, -1);
  
  	/* the sparkling new dquot */
  	xfs_trans_mod_dquot(tp, newdq, bfield, ip->i_d.di_nblocks);
  	xfs_trans_mod_dquot(tp, newdq, XFS_TRANS_DQ_ICOUNT, 1);
  
  	/*
  	 * Take an extra reference, because the inode
  	 * is going to keep this dquot pointer even
  	 * after the trans_commit.
  	 */
  	xfs_dqlock(newdq);
  	XFS_DQHOLD(newdq);
  	xfs_dqunlock(newdq);
  	*IO_olddq = newdq;
  
  	return prevdq;
  }
  
  /*
   * Quota reservations for setattr(AT_UID|AT_GID|AT_PROJID).
   */
  int
  xfs_qm_vop_chown_reserve(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*ip,
  	xfs_dquot_t	*udqp,
  	xfs_dquot_t	*gdqp,
  	uint		flags)
  {
  	xfs_mount_t	*mp = ip->i_mount;
  	uint		delblks, blkflags, prjflags = 0;
  	xfs_dquot_t	*unresudq, *unresgdq, *delblksudq, *delblksgdq;
  	int		error;
  
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
  	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
  
  	delblks = ip->i_delayed_blks;
  	delblksudq = delblksgdq = unresudq = unresgdq = NULL;
  	blkflags = XFS_IS_REALTIME_INODE(ip) ?
  			XFS_QMOPT_RES_RTBLKS : XFS_QMOPT_RES_REGBLKS;
  
  	if (XFS_IS_UQUOTA_ON(mp) && udqp &&
  	    ip->i_d.di_uid != (uid_t)be32_to_cpu(udqp->q_core.d_id)) {
  		delblksudq = udqp;
  		/*
  		 * If there are delayed allocation blocks, then we have to
  		 * unreserve those from the old dquot, and add them to the
  		 * new dquot.
  		 */
  		if (delblks) {
  			ASSERT(ip->i_udquot);
  			unresudq = ip->i_udquot;
  		}
  	}
  	if (XFS_IS_OQUOTA_ON(ip->i_mount) && gdqp) {
  		if (XFS_IS_PQUOTA_ON(ip->i_mount) &&
  		     ip->i_d.di_projid != be32_to_cpu(gdqp->q_core.d_id))
  			prjflags = XFS_QMOPT_ENOSPC;
  
  		if (prjflags ||
  		    (XFS_IS_GQUOTA_ON(ip->i_mount) &&
  		     ip->i_d.di_gid != be32_to_cpu(gdqp->q_core.d_id))) {
  			delblksgdq = gdqp;
  			if (delblks) {
  				ASSERT(ip->i_gdquot);
  				unresgdq = ip->i_gdquot;
  			}
  		}
  	}
  
  	if ((error = xfs_trans_reserve_quota_bydquots(tp, ip->i_mount,
  				delblksudq, delblksgdq, ip->i_d.di_nblocks, 1,
  				flags | blkflags | prjflags)))
  		return (error);
  
  	/*
  	 * Do the delayed blks reservations/unreservations now. Since, these
  	 * are done without the help of a transaction, if a reservation fails
  	 * its previous reservations won't be automatically undone by trans
  	 * code. So, we have to do it manually here.
  	 */
  	if (delblks) {
  		/*
  		 * Do the reservations first. Unreservation can't fail.
  		 */
  		ASSERT(delblksudq || delblksgdq);
  		ASSERT(unresudq || unresgdq);
  		if ((error = xfs_trans_reserve_quota_bydquots(NULL, ip->i_mount,
  				delblksudq, delblksgdq, (xfs_qcnt_t)delblks, 0,
  				flags | blkflags | prjflags)))
  			return (error);
  		xfs_trans_reserve_quota_bydquots(NULL, ip->i_mount,
  				unresudq, unresgdq, -((xfs_qcnt_t)delblks), 0,
  				blkflags);
  	}
  
  	return (0);
  }
  
  int
  xfs_qm_vop_rename_dqattach(
  	struct xfs_inode	**i_tab)
  {
  	struct xfs_mount	*mp = i_tab[0]->i_mount;
  	int			i;
  
  	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
  		return 0;
  
  	for (i = 0; (i < 4 && i_tab[i]); i++) {
  		struct xfs_inode	*ip = i_tab[i];
  		int			error;
  
  		/*
  		 * Watch out for duplicate entries in the table.
  		 */
  		if (i == 0 || ip != i_tab[i-1]) {
  			if (XFS_NOT_DQATTACHED(mp, ip)) {
  				error = xfs_qm_dqattach(ip, 0);
  				if (error)
  					return error;
  			}
  		}
  	}
  	return 0;
  }
  
  void
  xfs_qm_vop_create_dqattach(
  	struct xfs_trans	*tp,
  	struct xfs_inode	*ip,
  	struct xfs_dquot	*udqp,
  	struct xfs_dquot	*gdqp)
  {
  	struct xfs_mount	*mp = tp->t_mountp;
  
  	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
  		return;
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
  	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
  
  	if (udqp) {
  		xfs_dqlock(udqp);
  		XFS_DQHOLD(udqp);
  		xfs_dqunlock(udqp);
  		ASSERT(ip->i_udquot == NULL);
  		ip->i_udquot = udqp;
  		ASSERT(XFS_IS_UQUOTA_ON(mp));
  		ASSERT(ip->i_d.di_uid == be32_to_cpu(udqp->q_core.d_id));
  		xfs_trans_mod_dquot(tp, udqp, XFS_TRANS_DQ_ICOUNT, 1);
  	}
  	if (gdqp) {
  		xfs_dqlock(gdqp);
  		XFS_DQHOLD(gdqp);
  		xfs_dqunlock(gdqp);
  		ASSERT(ip->i_gdquot == NULL);
  		ip->i_gdquot = gdqp;
  		ASSERT(XFS_IS_OQUOTA_ON(mp));
  		ASSERT((XFS_IS_GQUOTA_ON(mp) ?
  			ip->i_d.di_gid : ip->i_d.di_projid) ==
  				be32_to_cpu(gdqp->q_core.d_id));
  		xfs_trans_mod_dquot(tp, gdqp, XFS_TRANS_DQ_ICOUNT, 1);
  	}
  }
  
  /* ------------- list stuff -----------------*/
  STATIC void
  xfs_qm_freelist_init(xfs_frlist_t *ql)
  {
  	ql->qh_next = ql->qh_prev = (xfs_dquot_t *) ql;
  	mutex_init(&ql->qh_lock);
  	ql->qh_version = 0;
  	ql->qh_nelems = 0;
  }
  
  STATIC void
  xfs_qm_freelist_destroy(xfs_frlist_t *ql)
  {
  	xfs_dquot_t	*dqp, *nextdqp;
  
  	mutex_lock(&ql->qh_lock);
  	for (dqp = ql->qh_next;
  	     dqp != (xfs_dquot_t *)ql; ) {
  		xfs_dqlock(dqp);
  		nextdqp = dqp->dq_flnext;
  #ifdef QUOTADEBUG
  		cmn_err(CE_DEBUG, "FREELIST destroy 0x%p", dqp);
  #endif
  		XQM_FREELIST_REMOVE(dqp);
  		xfs_dqunlock(dqp);
  		xfs_qm_dqdestroy(dqp);
  		dqp = nextdqp;
  	}
  	mutex_unlock(&ql->qh_lock);
  	mutex_destroy(&ql->qh_lock);
  
  	ASSERT(ql->qh_nelems == 0);
  }
  
  STATIC void
  xfs_qm_freelist_insert(xfs_frlist_t *ql, xfs_dquot_t *dq)
  {
  	dq->dq_flnext = ql->qh_next;
  	dq->dq_flprev = (xfs_dquot_t *)ql;
  	ql->qh_next = dq;
  	dq->dq_flnext->dq_flprev = dq;
  	xfs_Gqm->qm_dqfreelist.qh_nelems++;
  	xfs_Gqm->qm_dqfreelist.qh_version++;
  }
  
  void
  xfs_qm_freelist_unlink(xfs_dquot_t *dq)
  {
  	xfs_dquot_t *next = dq->dq_flnext;
  	xfs_dquot_t *prev = dq->dq_flprev;
  
  	next->dq_flprev = prev;
  	prev->dq_flnext = next;
  	dq->dq_flnext = dq->dq_flprev = dq;
  	xfs_Gqm->qm_dqfreelist.qh_nelems--;
  	xfs_Gqm->qm_dqfreelist.qh_version++;
  }
  
  void
  xfs_qm_freelist_append(xfs_frlist_t *ql, xfs_dquot_t *dq)
  {
  	xfs_qm_freelist_insert((xfs_frlist_t *)ql->qh_prev, dq);
  }
  