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_trans.h"
  #include "xfs_sb.h"
  #include "xfs_ag.h"
  #include "xfs_alloc.h"
  #include "xfs_quota.h"
  #include "xfs_mount.h"
  #include "xfs_bmap_btree.h"
  #include "xfs_ialloc_btree.h"
  #include "xfs_dinode.h"
  #include "xfs_inode.h"
  #include "xfs_ialloc.h"
  #include "xfs_itable.h"
  #include "xfs_rtalloc.h"
  #include "xfs_error.h"
  #include "xfs_bmap.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"
  #include "xfs_icache.h"
  #include "xfs_cksum.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.
   */
  STATIC int	xfs_qm_init_quotainos(xfs_mount_t *);
  STATIC int	xfs_qm_init_quotainfo(xfs_mount_t *);
  STATIC int	xfs_qm_shake(struct shrinker *, struct shrink_control *);
  
  /*
   * We use the batch lookup interface to iterate over the dquots as it
   * currently is the only interface into the radix tree code that allows
   * fuzzy lookups instead of exact matches.  Holding the lock over multiple
   * operations is fine as all callers are used either during mount/umount
   * or quotaoff.
   */
  #define XFS_DQ_LOOKUP_BATCH	32
  
  STATIC int
  xfs_qm_dquot_walk(
  	struct xfs_mount	*mp,
  	int			type,
  	int			(*execute)(struct xfs_dquot *dqp, void *data),
  	void			*data)
  {
  	struct xfs_quotainfo	*qi = mp->m_quotainfo;
  	struct radix_tree_root	*tree = XFS_DQUOT_TREE(qi, type);
  	uint32_t		next_index;
  	int			last_error = 0;
  	int			skipped;
  	int			nr_found;
  
  restart:
  	skipped = 0;
  	next_index = 0;
  	nr_found = 0;
  
  	while (1) {
  		struct xfs_dquot *batch[XFS_DQ_LOOKUP_BATCH];
  		int		error = 0;
  		int		i;
  
  		mutex_lock(&qi->qi_tree_lock);
  		nr_found = radix_tree_gang_lookup(tree, (void **)batch,
  					next_index, XFS_DQ_LOOKUP_BATCH);
  		if (!nr_found) {
  			mutex_unlock(&qi->qi_tree_lock);
  			break;
  		}
  
  		for (i = 0; i < nr_found; i++) {
  			struct xfs_dquot *dqp = batch[i];
  
  			next_index = be32_to_cpu(dqp->q_core.d_id) + 1;
  
  			error = execute(batch[i], data);
  			if (error == EAGAIN) {
  				skipped++;
  				continue;
  			}
  			if (error && last_error != EFSCORRUPTED)
  				last_error = error;
  		}
  
  		mutex_unlock(&qi->qi_tree_lock);
  
  		/* bail out if the filesystem is corrupted.  */
  		if (last_error == EFSCORRUPTED) {
  			skipped = 0;
  			break;
  		}
  	}
  
  	if (skipped) {
  		delay(1);
  		goto restart;
  	}
  
  	return last_error;
  }
  
  
  /*
   * Purge a dquot from all tracking data structures and free it.
   */
  STATIC int
  xfs_qm_dqpurge(
  	struct xfs_dquot	*dqp,
  	void			*data)
  {
  	struct xfs_mount	*mp = dqp->q_mount;
  	struct xfs_quotainfo	*qi = mp->m_quotainfo;
  	struct xfs_dquot	*gdqp = NULL;
  
  	xfs_dqlock(dqp);
  	if ((dqp->dq_flags & XFS_DQ_FREEING) || dqp->q_nrefs != 0) {
  		xfs_dqunlock(dqp);
  		return EAGAIN;
  	}
  
  	/*
  	 * If this quota has a group hint attached, prepare for releasing it
  	 * now.
  	 */
  	gdqp = dqp->q_gdquot;
  	if (gdqp) {
  		xfs_dqlock(gdqp);
  		dqp->q_gdquot = NULL;
  	}
  
  	dqp->dq_flags |= XFS_DQ_FREEING;
  
  	xfs_dqflock(dqp);
  
  	/*
  	 * If we are 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)) {
  		struct xfs_buf	*bp = NULL;
  		int		error;
  
  		/*
  		 * 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, &bp);
  		if (error) {
  			xfs_warn(mp, "%s: dquot %p flush failed",
  				__func__, dqp);
  		} else {
  			error = xfs_bwrite(bp);
  			xfs_buf_relse(bp);
  		}
  		xfs_dqflock(dqp);
  	}
  
  	ASSERT(atomic_read(&dqp->q_pincount) == 0);
  	ASSERT(XFS_FORCED_SHUTDOWN(mp) ||
  	       !(dqp->q_logitem.qli_item.li_flags & XFS_LI_IN_AIL));
  
  	xfs_dqfunlock(dqp);
  	xfs_dqunlock(dqp);
  
  	radix_tree_delete(XFS_DQUOT_TREE(qi, dqp->q_core.d_flags),
  			  be32_to_cpu(dqp->q_core.d_id));
  	qi->qi_dquots--;
  
  	/*
  	 * We move dquots to the freelist as soon as their reference count
  	 * hits zero, so it really should be on the freelist here.
  	 */
  	mutex_lock(&qi->qi_lru_lock);
  	ASSERT(!list_empty(&dqp->q_lru));
  	list_del_init(&dqp->q_lru);
  	qi->qi_lru_count--;
  	XFS_STATS_DEC(xs_qm_dquot_unused);
  	mutex_unlock(&qi->qi_lru_lock);
  
  	xfs_qm_dqdestroy(dqp);
  
  	if (gdqp)
  		xfs_qm_dqput(gdqp);
  	return 0;
  }
  
  /*
   * Purge the dquot cache.
   */
  void
  xfs_qm_dqpurge_all(
  	struct xfs_mount	*mp,
  	uint			flags)
  {
  	if (flags & XFS_QMOPT_UQUOTA)
  		xfs_qm_dquot_walk(mp, XFS_DQ_USER, xfs_qm_dqpurge, NULL);
  	if (flags & XFS_QMOPT_GQUOTA)
  		xfs_qm_dquot_walk(mp, XFS_DQ_GROUP, xfs_qm_dqpurge, NULL);
  	if (flags & XFS_QMOPT_PQUOTA)
  		xfs_qm_dquot_walk(mp, XFS_DQ_PROJ, xfs_qm_dqpurge, NULL);
  }
  
  /*
   * 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_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) {
  		xfs_notice(mp, "Cannot turn on quotas for realtime filesystem");
  		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_alert(mp, "%s: Superblock update failed!",
  				__func__);
  		}
  	}
  
  	if (error) {
  		xfs_warn(mp, "Failed to initialize disk quotas.");
  		return;
  	}
  }
  
  /*
   * 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;
  		}
  	}
  }
  
  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) {
  			ASSERT(*IO_idqpp == NULL);
  
  			*IO_idqpp = xfs_qm_dqhold(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,
  			     doalloc | 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.
   */
  STATIC void
  xfs_qm_dqattach_grouphint(
  	xfs_dquot_t	*udq,
  	xfs_dquot_t	*gdq)
  {
  	xfs_dquot_t	*tmp;
  
  	xfs_dqlock(udq);
  
  	tmp = udq->q_gdquot;
  	if (tmp) {
  		if (tmp == gdq)
  			goto done;
  
  		udq->q_gdquot = NULL;
  		xfs_qm_dqrele(tmp);
  	}
  
  	udq->q_gdquot = xfs_qm_dqhold(gdq);
  done:
  	xfs_dqunlock(udq);
  }
  
  static bool
  xfs_qm_need_dqattach(
  	struct xfs_inode	*ip)
  {
  	struct xfs_mount	*mp = ip->i_mount;
  
  	if (!XFS_IS_QUOTA_RUNNING(mp))
  		return false;
  	if (!XFS_IS_QUOTA_ON(mp))
  		return false;
  	if (!XFS_NOT_DQATTACHED(mp, ip))
  		return false;
  	if (ip->i_ino == mp->m_sb.sb_uquotino ||
  	    ip->i_ino == mp->m_sb.sb_gquotino)
  		return false;
  	return true;
  }
  
  /*
   * 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_qm_need_dqattach(ip))
  		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, xfs_get_projid(ip), 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 do not have 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)
  			xfs_qm_dqattach_grouphint(ip->i_udquot, ip->i_gdquot);
  	}
  
   done:
  #ifdef DEBUG
  	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;
  
  	if (!xfs_qm_need_dqattach(ip))
  		return 0;
  
  	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_calc_dquots_per_chunk(
  	struct xfs_mount	*mp,
  	unsigned int		nbblks)	/* basic block units */
  {
  	unsigned int	ndquots;
  
  	ASSERT(nbblks > 0);
  	ndquots = BBTOB(nbblks);
  	do_div(ndquots, sizeof(xfs_dqblk_t));
  
  	return ndquots;
  }
  
  /*
   * 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));
  
  	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;
  	}
  
  	INIT_RADIX_TREE(&qinf->qi_uquota_tree, GFP_NOFS);
  	INIT_RADIX_TREE(&qinf->qi_gquota_tree, GFP_NOFS);
  	mutex_init(&qinf->qi_tree_lock);
  
  	INIT_LIST_HEAD(&qinf->qi_lru_list);
  	qinf->qi_lru_count = 0;
  	mutex_init(&qinf->qi_lru_lock);
  
  	/* 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);
  	qinf->qi_dqperchunk = xfs_qm_calc_dquots_per_chunk(mp,
  							qinf->qi_dqchunklen);
  
  	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.
  	 *
  	 * Since we may not have done a quotacheck by this point, just read
  	 * the dquot without attaching it to any hashtables or lists.
  	 */
  	error = xfs_qm_dqread(mp, 0,
  			XFS_IS_UQUOTA_RUNNING(mp) ? XFS_DQ_USER :
  			 (XFS_IS_GQUOTA_RUNNING(mp) ? XFS_DQ_GROUP :
  			  XFS_DQ_PROJ),
  			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);
   
  		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;
  	}
  
  	qinf->qi_shrinker.shrink = xfs_qm_shake;
  	qinf->qi_shrinker.seeks = DEFAULT_SEEKS;
  	register_shrinker(&qinf->qi_shrinker);
  	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);
  
  	unregister_shrinker(&qi->qi_shrinker);
  
  	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;
  }
  
  /*
   * 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;
  	}
  
  	error = xfs_dir_ialloc(&tp, NULL, S_IFREG, 1, 0, 0, 1, ip, &committed);
  	if (error) {
  		xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES |
  				 XFS_TRANS_ABORT);
  		return error;
  	}
  
  	/*
  	 * 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) {
  		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 (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_alert(mp, "%s failed (error %d)!", __func__, error);
  		return error;
  	}
  	return 0;
  }
  
  
  STATIC void
  xfs_qm_reset_dqcounts(
  	xfs_mount_t	*mp,
  	xfs_buf_t	*bp,
  	xfs_dqid_t	id,
  	uint		type)
  {
  	struct xfs_dqblk	*dqb;
  	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(mp->m_quotainfo->qi_dqperchunk == j);
  #endif
  	dqb = bp->b_addr;
  	for (j = 0; j < mp->m_quotainfo->qi_dqperchunk; j++) {
  		struct xfs_disk_dquot	*ddq;
  
  		ddq = (struct xfs_disk_dquot *)&dqb[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(mp, 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;
  
  		if (xfs_sb_version_hascrc(&mp->m_sb)) {
  			xfs_update_cksum((char *)&dqb[j],
  					 sizeof(struct xfs_dqblk),
  					 XFS_DQUOT_CRC_OFF);
  		}
  	}
  }
  
  STATIC int
  xfs_qm_dqiter_bufs(
  	struct xfs_mount	*mp,
  	xfs_dqid_t		firstid,
  	xfs_fsblock_t		bno,
  	xfs_filblks_t		blkcnt,
  	uint			flags,
  	struct list_head	*buffer_list)
  {
  	struct xfs_buf		*bp;
  	int			error;
  	int			type;
  
  	ASSERT(blkcnt > 0);
  	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),
  			      mp->m_quotainfo->qi_dqchunklen, 0, &bp,
  			      &xfs_dquot_buf_ops);
  
  		/*
  		 * CRC and validation errors will return a EFSCORRUPTED here. If
  		 * this occurs, re-read without CRC validation so that we can
  		 * repair the damage via xfs_qm_reset_dqcounts(). This process
  		 * will leave a trace in the log indicating corruption has
  		 * been detected.
  		 */
  		if (error == EFSCORRUPTED) {
  			error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
  				      XFS_FSB_TO_DADDR(mp, bno),
  				      mp->m_quotainfo->qi_dqchunklen, 0, &bp,
  				      NULL);
  		}
  
  		if (error)
  			break;
  
  		xfs_qm_reset_dqcounts(mp, bp, firstid, type);
  		xfs_buf_delwri_queue(bp, buffer_list);
  		xfs_buf_relse(bp);
  
  		/* goto the next block. */
  		bno++;
  		firstid += mp->m_quotainfo->qi_dqperchunk;
  	}
  
  	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(
  	struct xfs_mount	*mp,
  	struct xfs_inode	*qip,
  	uint			flags,
  	struct list_head	*buffer_list)
  {
  	struct xfs_bmbt_irec	*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, mp->m_super->s_maxbytes);
  	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_read(qip, lblkno, maxlblkcnt - lblkno,
  				       map, &nmaps, 0);
  		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 *
  				mp->m_quotainfo->qi_dqperchunk;
  			/*
  			 * 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_buf_readahead(mp->m_ddev_targp,
  					       XFS_FSB_TO_DADDR(mp, rablkno),
  					       mp->m_quotainfo->qi_dqchunklen,
  					       NULL);
  					rablkno++;
  				}
  			}
  			/*
  			 * Iterate thru all the blks in the extent and
  			 * reset the counters of all the dquots inside them.
  			 */
  			error = xfs_qm_dqiter_bufs(mp, firstid,
  						   map[i].br_startblock,
  						   map[i].br_blockcount,
  						   flags, buffer_list);
  			if (error)
  				goto out;
  		}
  	} while (nmaps > 0);
  
  out:
  	kmem_free(map);
  	return error;
  }
  
  /*
   * Called by dqusage_adjust in doing a quotacheck.
   *
   * Given the inode, and a dquot id this updates both the incore dqout 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 int
  xfs_qm_quotacheck_dqadjust(
  	struct xfs_inode	*ip,
  	xfs_dqid_t		id,
  	uint			type,
  	xfs_qcnt_t		nblks,
  	xfs_qcnt_t		rtblks)
  {
  	struct xfs_mount	*mp = ip->i_mount;
  	struct xfs_dquot	*dqp;
  	int			error;
  
  	error = xfs_qm_dqget(mp, ip, id, type,
  			     XFS_QMOPT_DQALLOC | XFS_QMOPT_DOWARN, &dqp);
  	if (error) {
  		/*
  		 * Shouldn't be able to turn off quotas here.
  		 */
  		ASSERT(error != ESRCH);
  		ASSERT(error != ENOENT);
  		return error;
  	}
  
  	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)
  	 *
  	 * There are no timers for the default values set in the root dquot.
  	 */
  	if (dqp->q_core.d_id) {
  		xfs_qm_adjust_dqlimits(mp, dqp);
  		xfs_qm_adjust_dqtimers(mp, &dqp->q_core);
  	}
  
  	dqp->dq_flags |= XFS_DQ_DIRTY;
  	xfs_qm_dqput(dqp);
  	return 0;
  }
  
  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 */
  	int		*ubused,	/* not used */
  	int		*res)		/* result code value */
  {
  	xfs_inode_t	*ip;
  	xfs_qcnt_t	nblks, rtblks = 0;
  	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.
  	 */
  	error = xfs_iget(mp, NULL, ino, 0, XFS_ILOCK_EXCL, &ip);
  	if (error) {
  		*res = BULKSTAT_RV_NOTHING;
  		return error;
  	}
  
  	ASSERT(ip->i_delayed_blks == 0);
  
  	if (XFS_IS_REALTIME_INODE(ip)) {
  		/*
  		 * Walk thru the extent list and count the realtime blocks.
  		 */
  		error = xfs_qm_get_rtblks(ip, &rtblks);
  		if (error)
  			goto error0;
  	}
  
  	nblks = (xfs_qcnt_t)ip->i_d.di_nblocks - rtblks;
  
  	/*
  	 * 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)) {
  		error = xfs_qm_quotacheck_dqadjust(ip, ip->i_d.di_uid,
  						   XFS_DQ_USER, nblks, rtblks);
  		if (error)
  			goto error0;
  	}
  
  	if (XFS_IS_GQUOTA_ON(mp)) {
  		error = xfs_qm_quotacheck_dqadjust(ip, ip->i_d.di_gid,
  						   XFS_DQ_GROUP, nblks, rtblks);
  		if (error)
  			goto error0;
  	}
  
  	if (XFS_IS_PQUOTA_ON(mp)) {
  		error = xfs_qm_quotacheck_dqadjust(ip, xfs_get_projid(ip),
  						   XFS_DQ_PROJ, nblks, rtblks);
  		if (error)
  			goto error0;
  	}
  
  	xfs_iunlock(ip, XFS_ILOCK_EXCL);
  	IRELE(ip);
  	*res = BULKSTAT_RV_DIDONE;
  	return 0;
  
  error0:
  	xfs_iunlock(ip, XFS_ILOCK_EXCL);
  	IRELE(ip);
  	*res = BULKSTAT_RV_GIVEUP;
  	return error;
  }
  
  STATIC int
  xfs_qm_flush_one(
  	struct xfs_dquot	*dqp,
  	void			*data)
  {
  	struct list_head	*buffer_list = data;
  	struct xfs_buf		*bp = NULL;
  	int			error = 0;
  
  	xfs_dqlock(dqp);
  	if (dqp->dq_flags & XFS_DQ_FREEING)
  		goto out_unlock;
  	if (!XFS_DQ_IS_DIRTY(dqp))
  		goto out_unlock;
  
  	xfs_dqflock(dqp);
  	error = xfs_qm_dqflush(dqp, &bp);
  	if (error)
  		goto out_unlock;
  
  	xfs_buf_delwri_queue(bp, buffer_list);
  	xfs_buf_relse(bp);
  out_unlock:
  	xfs_dqunlock(dqp);
  	return error;
  }
  
  /*
   * 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, error2;
  	xfs_ino_t	lastino;
  	size_t		structsz;
  	xfs_inode_t	*uip, *gip;
  	uint		flags;
  	LIST_HEAD	(buffer_list);
  
  	count = INT_MAX;
  	structsz = 1;
  	lastino = 0;
  	flags = 0;
  
  	ASSERT(mp->m_quotainfo->qi_uquotaip || mp->m_quotainfo->qi_gquotaip);
  	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
  
  	xfs_notice(mp, "Quotacheck needed: Please wait.");
  
  	/*
  	 * 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.
  	 */
  	uip = mp->m_quotainfo->qi_uquotaip;
  	if (uip) {
  		error = xfs_qm_dqiterate(mp, uip, XFS_QMOPT_UQUOTA,
  					 &buffer_list);
  		if (error)
  			goto error_return;
  		flags |= XFS_UQUOTA_CHKD;
  	}
  
  	gip = mp->m_quotainfo->qi_gquotaip;
  	if (gip) {
  		error = xfs_qm_dqiterate(mp, gip, XFS_IS_GQUOTA_ON(mp) ?
  					 XFS_QMOPT_GQUOTA : XFS_QMOPT_PQUOTA,
  					 &buffer_list);
  		if (error)
  			goto error_return;
  		flags |= XFS_OQUOTA_CHKD;
  	}
  
  	do {
  		/*
  		 * Iterate thru all the inodes in the file system,
  		 * adjusting the corresponding dquot counters in core.
  		 */
  		error = xfs_bulkstat(mp, &lastino, &count,
  				     xfs_qm_dqusage_adjust,
  				     structsz, NULL, &done);
  		if (error)
  			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 (XFS_IS_UQUOTA_ON(mp)) {
  		error = xfs_qm_dquot_walk(mp, XFS_DQ_USER, xfs_qm_flush_one,
  					  &buffer_list);
  	}
  	if (XFS_IS_GQUOTA_ON(mp)) {
  		error2 = xfs_qm_dquot_walk(mp, XFS_DQ_GROUP, xfs_qm_flush_one,
  					   &buffer_list);
  		if (!error)
  			error = error2;
  	}
  	if (XFS_IS_PQUOTA_ON(mp)) {
  		error2 = xfs_qm_dquot_walk(mp, XFS_DQ_PROJ, xfs_qm_flush_one,
  					   &buffer_list);
  		if (!error)
  			error = error2;
  	}
  
  	error2 = xfs_buf_delwri_submit(&buffer_list);
  	if (!error)
  		error = error2;
  
  	/*
  	 * 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);
  		goto error_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.
  	 */
  	mp->m_qflags &= ~XFS_ALL_QUOTA_CHKD;
  	mp->m_qflags |= flags;
  
   error_return:
  	while (!list_empty(&buffer_list)) {
  		struct xfs_buf *bp =
  			list_first_entry(&buffer_list, struct xfs_buf, b_list);
  		list_del_init(&bp->b_list);
  		xfs_buf_relse(bp);
  	}
  
  	if (error) {
  		xfs_warn(mp,
  	"Quotacheck: Unsuccessful (Error %d): Disabling quotas.",
  			error);
  		/*
  		 * We must turn off quotas.
  		 */
  		ASSERT(mp->m_quotainfo != NULL);
  		xfs_qm_destroy_quotainfo(mp);
  		if (xfs_mount_reset_sbqflags(mp)) {
  			xfs_warn(mp,
  				"Quotacheck: Failed to reset quota flags.");
  		}
  	} else
  		xfs_notice(mp, "Quotacheck: Done.");
  	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)))
  				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))) {
  				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);
  		}
  	}
  
  	mp->m_quotainfo->qi_uquotaip = uip;
  	mp->m_quotainfo->qi_gquotaip = gip;
  
  	return 0;
  }
  
  STATIC void
  xfs_qm_dqfree_one(
  	struct xfs_dquot	*dqp)
  {
  	struct xfs_mount	*mp = dqp->q_mount;
  	struct xfs_quotainfo	*qi = mp->m_quotainfo;
  
  	mutex_lock(&qi->qi_tree_lock);
  	radix_tree_delete(XFS_DQUOT_TREE(qi, dqp->q_core.d_flags),
  			  be32_to_cpu(dqp->q_core.d_id));
  
  	qi->qi_dquots--;
  	mutex_unlock(&qi->qi_tree_lock);
  
  	xfs_qm_dqdestroy(dqp);
  }
  
  STATIC void
  xfs_qm_dqreclaim_one(
  	struct xfs_dquot	*dqp,
  	struct list_head	*buffer_list,
  	struct list_head	*dispose_list)
  {
  	struct xfs_mount	*mp = dqp->q_mount;
  	struct xfs_quotainfo	*qi = mp->m_quotainfo;
  	int			error;
  
  	if (!xfs_dqlock_nowait(dqp))
  		goto out_move_tail;
  
  	/*
  	 * This dquot has acquired a reference in the meantime remove it from
  	 * the freelist and try again.
  	 */
  	if (dqp->q_nrefs) {
  		xfs_dqunlock(dqp);
  
  		trace_xfs_dqreclaim_want(dqp);
  		XFS_STATS_INC(xs_qm_dqwants);
  
  		list_del_init(&dqp->q_lru);
  		qi->qi_lru_count--;
  		XFS_STATS_DEC(xs_qm_dquot_unused);
  		return;
  	}
  
  	/*
  	 * 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))
  		goto out_unlock_move_tail;
  
  	if (XFS_DQ_IS_DIRTY(dqp)) {
  		struct xfs_buf	*bp = NULL;
  
  		trace_xfs_dqreclaim_dirty(dqp);
  
  		error = xfs_qm_dqflush(dqp, &bp);
  		if (error) {
  			xfs_warn(mp, "%s: dquot %p flush failed",
  				 __func__, dqp);
  			goto out_unlock_move_tail;
  		}
  
  		xfs_buf_delwri_queue(bp, buffer_list);
  		xfs_buf_relse(bp);
  		/*
  		 * Give the dquot another try on the freelist, as the
  		 * flushing will take some time.
  		 */
  		goto out_unlock_move_tail;
  	}
  	xfs_dqfunlock(dqp);
  
  	/*
  	 * Prevent lookups now that we are past the point of no return.
  	 */
  	dqp->dq_flags |= XFS_DQ_FREEING;
  	xfs_dqunlock(dqp);
  
  	ASSERT(dqp->q_nrefs == 0);
  	list_move_tail(&dqp->q_lru, dispose_list);
  	qi->qi_lru_count--;
  	XFS_STATS_DEC(xs_qm_dquot_unused);
  
  	trace_xfs_dqreclaim_done(dqp);
  	XFS_STATS_INC(xs_qm_dqreclaims);
  	return;
  
  	/*
  	 * Move the dquot to the tail of the list so that we don't spin on it.
  	 */
  out_unlock_move_tail:
  	xfs_dqunlock(dqp);
  out_move_tail:
  	list_move_tail(&dqp->q_lru, &qi->qi_lru_list);
  	trace_xfs_dqreclaim_busy(dqp);
  	XFS_STATS_INC(xs_qm_dqreclaim_misses);
  }
  
  STATIC int
  xfs_qm_shake(
  	struct shrinker		*shrink,
  	struct shrink_control	*sc)
  {
  	struct xfs_quotainfo	*qi =
  		container_of(shrink, struct xfs_quotainfo, qi_shrinker);
  	int			nr_to_scan = sc->nr_to_scan;
  	LIST_HEAD		(buffer_list);
  	LIST_HEAD		(dispose_list);
  	struct xfs_dquot	*dqp;
  	int			error;
  
  	if ((sc->gfp_mask & (__GFP_FS|__GFP_WAIT)) != (__GFP_FS|__GFP_WAIT))
  		return 0;
  	if (!nr_to_scan)
  		goto out;
  
  	mutex_lock(&qi->qi_lru_lock);
  	while (!list_empty(&qi->qi_lru_list)) {
  		if (nr_to_scan-- <= 0)
  			break;
  		dqp = list_first_entry(&qi->qi_lru_list, struct xfs_dquot,
  				       q_lru);
  		xfs_qm_dqreclaim_one(dqp, &buffer_list, &dispose_list);
  	}
  	mutex_unlock(&qi->qi_lru_lock);
  
  	error = xfs_buf_delwri_submit(&buffer_list);
  	if (error)
  		xfs_warn(NULL, "%s: dquot reclaim failed", __func__);
  
  	while (!list_empty(&dispose_list)) {
  		dqp = list_first_entry(&dispose_list, struct xfs_dquot, q_lru);
  		list_del_init(&dqp->q_lru);
  		xfs_qm_dqfree_one(dqp);
  	}
  
  out:
  	return (qi->qi_lru_count / 100) * sysctl_vfs_cache_pressure;
  }
  
  /*
   * 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;
  
  	tp = xfs_trans_alloc(mp, XFS_TRANS_QM_SBCHANGE);
  	error = xfs_trans_reserve(tp, 0, XFS_QM_SBCHANGE_LOG_RES(mp),
  				  0, 0, XFS_DEFAULT_LOG_COUNT);
  	if (error) {
  		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, gid and prid 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 = xfs_qm_dqhold(ip->i_udquot);
  		}
  	}
  	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 = xfs_qm_dqhold(ip->i_gdquot);
  		}
  	} else if ((flags & XFS_QMOPT_PQUOTA) && XFS_IS_PQUOTA_ON(mp)) {
  		if (xfs_get_projid(ip) != 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 = xfs_qm_dqhold(ip->i_gdquot);
  		}
  	}
  	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.
  	 */
  	*IO_olddq = xfs_qm_dqhold(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) &&
  		     xfs_get_projid(ip) != 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) {
  		ASSERT(ip->i_udquot == NULL);
  		ASSERT(XFS_IS_UQUOTA_ON(mp));
  		ASSERT(ip->i_d.di_uid == be32_to_cpu(udqp->q_core.d_id));
  
  		ip->i_udquot = xfs_qm_dqhold(udqp);
  		xfs_trans_mod_dquot(tp, udqp, XFS_TRANS_DQ_ICOUNT, 1);
  	}
  	if (gdqp) {
  		ASSERT(ip->i_gdquot == NULL);
  		ASSERT(XFS_IS_OQUOTA_ON(mp));
  		ASSERT((XFS_IS_GQUOTA_ON(mp) ?
  			ip->i_d.di_gid : xfs_get_projid(ip)) ==
  				be32_to_cpu(gdqp->q_core.d_id));
  
  		ip->i_gdquot = xfs_qm_dqhold(gdqp);
  		xfs_trans_mod_dquot(tp, gdqp, XFS_TRANS_DQ_ICOUNT, 1);
  	}
  }
  
  