Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs

* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: fix tracing builds inside the source tree
  xfs: remove subdirectories
  xfs: don't expect xfs headers to be in subdirectories

1 files changed, 2416 insertions, 0 deletions

diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
new file mode 100644
index 0000000..9a0aa76
--- /dev/null
+++ b/fs/xfs/xfs_qm.c
@@ -0,0 +1,2416 @@
+/*
+ * 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_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"
+
+/*
+ * 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 void	xfs_qm_list_init(xfs_dqlist_t *, char *, int);
+STATIC void	xfs_qm_list_destroy(xfs_dqlist_t *);
+
+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 *);
+
+static struct shrinker xfs_qm_shaker = {
+	.shrink = xfs_qm_shake,
+	.seeks = DEFAULT_SEEKS,
+};
+
+/*
+ * 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));
+	if (!udqhash)
+		goto out;
+
+	gdqhash = kmem_zalloc_large(hsize);
+	if (!gdqhash)
+		goto out_free_udqhash;
+
+	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
+	 */
+	INIT_LIST_HEAD(&xqm->qm_dqfrlist);
+	xqm->qm_dqfrlist_cnt = 0;
+	mutex_init(&xqm->qm_dqfrlist_lock);
+
+	/*
+	 * 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;
+	return xqm;
+
+ out_free_udqhash:
+	kmem_free_large(udqhash);
+ out:
+	return NULL;
+}
+
+/*
+ * Destroy the global quota manager when its reference count goes to zero.
+ */
+STATIC void
+xfs_qm_destroy(
+	struct xfs_qm	*xqm)
+{
+	struct xfs_dquot *dqp, *n;
+	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_large(xqm->qm_usr_dqhtable);
+	kmem_free_large(xqm->qm_grp_dqhtable);
+	xqm->qm_usr_dqhtable = NULL;
+	xqm->qm_grp_dqhtable = NULL;
+	xqm->qm_dqhashmask = 0;
+
+	/* frlist cleanup */
+	mutex_lock(&xqm->qm_dqfrlist_lock);
+	list_for_each_entry_safe(dqp, n, &xqm->qm_dqfrlist, q_freelist) {
+		xfs_dqlock(dqp);
+		list_del_init(&dqp->q_freelist);
+		xfs_Gqm->qm_dqfrlist_cnt--;
+		xfs_dqunlock(dqp);
+		xfs_qm_dqdestroy(dqp);
+	}
+	mutex_unlock(&xqm->qm_dqfrlist_lock);
+	mutex_destroy(&xqm->qm_dqfrlist_lock);
+	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) {
+		xfs_Gqm = xfs_Gqm_init();
+		if (!xfs_Gqm) {
+			mutex_unlock(&xfs_Gqm_lock);
+			return ENOMEM;
+		}
+	}
+
+	/*
+	 * 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, *n;
+
+	ASSERT(xfs_Gqm);
+	ASSERT(xfs_Gqm->qm_nrefs > 0);
+
+	/*
+	 * Go thru the freelist and destroy all inactive dquots.
+	 */
+	mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
+
+	list_for_each_entry_safe(dqp, n, &xfs_Gqm->qm_dqfrlist, q_freelist) {
+		xfs_dqlock(dqp);
+		if (dqp->dq_flags & XFS_DQ_INACTIVE) {
+			ASSERT(dqp->q_mount == NULL);
+			ASSERT(! XFS_DQ_IS_DIRTY(dqp));
+			ASSERT(list_empty(&dqp->q_hashlist));
+			ASSERT(list_empty(&dqp->q_mplist));
+			list_del_init(&dqp->q_freelist);
+			xfs_Gqm->qm_dqfrlist_cnt--;
+			xfs_dqunlock(dqp);
+			xfs_qm_dqdestroy(dqp);
+		} else {
+			xfs_dqunlock(dqp);
+		}
+	}
+	mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
+
+	/*
+	 * 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_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;
+		}
+	}
+}
+
+/*
+ * 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(
+	struct xfs_mount	*mp,
+	int			sync_mode)
+{
+	struct xfs_quotainfo	*q = mp->m_quotainfo;
+	int			recl;
+	struct xfs_dquot	*dqp;
+	int			error;
+
+	if (!q)
+		return 0;
+again:
+	mutex_lock(&q->qi_dqlist_lock);
+	list_for_each_entry(dqp, &q->qi_dqlist, q_mplist) {
+		xfs_dqlock(dqp);
+		if (! XFS_DQ_IS_DIRTY(dqp)) {
+			xfs_dqunlock(dqp);
+			continue;
+		}
+
+		/* XXX a sentinel would be better */
+		recl = q->qi_dqreclaims;
+		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.
+		 */
+		mutex_unlock(&q->qi_dqlist_lock);
+		error = xfs_qm_dqflush(dqp, sync_mode);
+		xfs_dqunlock(dqp);
+		if (error)
+			return error;
+
+		mutex_lock(&q->qi_dqlist_lock);
+		if (recl != q->qi_dqreclaims) {
+			mutex_unlock(&q->qi_dqlist_lock);
+			/* XXX restart limit */
+			goto again;
+		}
+	}
+
+	mutex_unlock(&q->qi_dqlist_lock);
+	/* 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(
+	struct xfs_mount	*mp)
+{
+	struct xfs_quotainfo	*q = mp->m_quotainfo;
+	struct xfs_dquot	*dqp, *gdqp;
+	int			nrecl;
+
+ again:
+	ASSERT(mutex_is_locked(&q->qi_dqlist_lock));
+	list_for_each_entry(dqp, &q->qi_dqlist, q_mplist) {
+		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 = q->qi_dqreclaims;
+			mutex_unlock(&q->qi_dqlist_lock);
+			xfs_qm_dqput(gdqp);
+
+			mutex_lock(&q->qi_dqlist_lock);
+			if (nrecl != q->qi_dqreclaims)
+				goto again;
+		}
+	}
+}
+
+/*
+ * 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(
+	struct xfs_mount	*mp,
+	uint			flags)
+{
+	struct xfs_quotainfo	*q = mp->m_quotainfo;
+	struct xfs_dquot	*dqp, *n;
+	uint			dqtype;
+	int			nrecl;
+	int			nmisses;
+
+	if (!q)
+		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;
+
+	mutex_lock(&q->qi_dqlist_lock);
+
+	/*
+	 * 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(mutex_is_locked(&q->qi_dqlist_lock));
+	/*
+	 * 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.
+	 */
+	list_for_each_entry_safe(dqp, n, &q->qi_dqlist, q_mplist) {
+		/*
+		 * 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)
+			continue;
+
+		if (!mutex_trylock(&dqp->q_hash->qh_lock)) {
+			nrecl = q->qi_dqreclaims;
+			mutex_unlock(&q->qi_dqlist_lock);
+			mutex_lock(&dqp->q_hash->qh_lock);
+			mutex_lock(&q->qi_dqlist_lock);
+
+			/*
+			 * 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 != q->qi_dqreclaims) {
+				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.
+		 */
+		nmisses += xfs_qm_dqpurge(dqp);
+	}
+	mutex_unlock(&q->qi_dqlist_lock);
+	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, 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 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 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;
+
+	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(
+	struct xfs_mount	*mp,
+	int			flags)
+{
+	struct xfs_quotainfo	*q = mp->m_quotainfo;
+	int			recl, restarts;
+	struct xfs_dquot	*dqp;
+	int			error;
+
+	if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
+		return 0;
+
+	restarts = 0;
+
+  again:
+	mutex_lock(&q->qi_dqlist_lock);
+	/*
+	 * 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)) {
+		mutex_unlock(&q->qi_dqlist_lock);
+		return 0;
+	}
+	ASSERT(mutex_is_locked(&q->qi_dqlist_lock));
+	list_for_each_entry(dqp, &q->qi_dqlist, q_mplist) {
+		/*
+		 * 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 = q->qi_dqreclaims;
+		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
+		 */
+		mutex_unlock(&q->qi_dqlist_lock);
+		error = xfs_qm_dqflush(dqp, flags);
+		xfs_dqunlock(dqp);
+		if (error && XFS_FORCED_SHUTDOWN(mp))
+			return 0;	/* Need to prevent umount failure */
+		else if (error)
+			return error;
+
+		mutex_lock(&q->qi_dqlist_lock);
+		if (recl != q->qi_dqreclaims) {
+			if (++restarts >= XFS_QM_SYNC_MAX_RESTARTS)
+				break;
+
+			mutex_unlock(&q->qi_dqlist_lock);
+			goto again;
+		}
+	}
+
+	mutex_unlock(&q->qi_dqlist_lock);
+	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;
+	}
+
+	INIT_LIST_HEAD(&qinf->qi_dqlist);
+	mutex_init(&qinf->qi_dqlist_lock);
+	lockdep_set_class(&qinf->qi_dqlist_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);
+
+	ASSERT(list_empty(&qi->qi_dqlist));
+	mutex_destroy(&qi->qi_dqlist_lock);
+
+	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);
+	INIT_LIST_HEAD(&list->qh_list);
+	list->qh_version = 0;
+	list->qh_nelems = 0;
+}
+
+STATIC void
+xfs_qm_list_destroy(
+	xfs_dqlist_t	*list)
+{
+	mutex_destroy(&(list->qh_lock));
+}
+
+/*
+ * 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)
+{
+	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(mp->m_quotainfo->qi_dqperchunk == j);
+#endif
+	ddq = bp->b_addr;
+	for (j = 0; j < mp->m_quotainfo->qi_dqperchunk; 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;
+		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		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);
+		if (error)
+			break;
+
+		xfs_qm_reset_dqcounts(mp, bp, firstid, type);
+		xfs_bdwrite(mp, 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(
+	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);
+		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);
+					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 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->q_core);
+		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;
+}
+
+/*
+ * 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(mp->m_quotainfo->qi_uquotaip || mp->m_quotainfo->qi_gquotaip);
+	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
+
+	/*
+	 * There should be no cached dquots. The (simplistic) quotacheck
+	 * algorithm doesn't like that.
+	 */
+	ASSERT(list_empty(&mp->m_quotainfo->qi_dqlist));
+
+	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);
+		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);
+		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 (!error)
+		error = xfs_qm_dqflush_all(mp, 0);
+
+	/*
+	 * 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;
+	}
+
+	/*
+	 * 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;
+
+ error_return:
+	if (error) {
+		xfs_warn(mp,
+	"Quotacheck: Unsuccessful (Error %d): Disabling quotas.",
+			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)) {
+			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;
+}
+
+
+
+/*
+ * 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		startagain;
+
+	restarts = 0;
+	dqpout = NULL;
+
+	/* lockorder: hashchainlock, freelistlock, mplistlock, dqlock, dqflock */
+again:
+	startagain = 0;
+	mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
+
+	list_for_each_entry(dqp, &xfs_Gqm->qm_dqfrlist, q_freelist) {
+		struct xfs_mount *mp = dqp->q_mount;
+		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);
+			XQM_STATS_INC(xqmstats.xs_qm_dqwants);
+			restarts++;
+			startagain = 1;
+			goto dqunlock;
+		}
+
+		/*
+		 * 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(mp == NULL);
+			ASSERT(! XFS_DQ_IS_DIRTY(dqp));
+			ASSERT(list_empty(&dqp->q_hashlist));
+			ASSERT(list_empty(&dqp->q_mplist));
+			list_del_init(&dqp->q_freelist);
+			xfs_Gqm->qm_dqfrlist_cnt--;
+			dqpout = dqp;
+			XQM_STATS_INC(xqmstats.xs_qm_dqinact_reclaims);
+			goto dqunlock;
+		}
+
+		ASSERT(dqp->q_hash);
+		ASSERT(!list_empty(&dqp->q_mplist));
+
+		/*
+		 * 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 dqunlock;
+
+		/*
+		 * 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, 0);
+			if (error) {
+				xfs_warn(mp, "%s: dquot %p flush failed",
+					__func__, dqp);
+			}
+			goto dqunlock;
+		}
+
+		/*
+		 * 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)) {
+			restarts++;
+			goto dqfunlock;
+		}
+
+		/*
+		 * 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.
+		 */
+		if (!mutex_trylock(&mp->m_quotainfo->qi_dqlist_lock)) {
+			restarts++;
+			startagain = 1;
+			goto qhunlock;
+		}
+
+		ASSERT(dqp->q_nrefs == 0);
+		list_del_init(&dqp->q_mplist);
+		mp->m_quotainfo->qi_dquots--;
+		mp->m_quotainfo->qi_dqreclaims++;
+		list_del_init(&dqp->q_hashlist);
+		dqp->q_hash->qh_version++;
+		list_del_init(&dqp->q_freelist);
+		xfs_Gqm->qm_dqfrlist_cnt--;
+		dqpout = dqp;
+		mutex_unlock(&mp->m_quotainfo->qi_dqlist_lock);
+qhunlock:
+		mutex_unlock(&dqp->q_hash->qh_lock);
+dqfunlock:
+		xfs_dqfunlock(dqp);
+dqunlock:
+		xfs_dqunlock(dqp);
+		if (dqpout)
+			break;
+		if (restarts >= XFS_QM_RECLAIM_MAX_RESTARTS)
+			break;
+		if (startagain) {
+			mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
+			goto again;
+		}
+	}
+	mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
+	return dqpout;
+}
+
+/*
+ * 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 ...
+ */
+STATIC int
+xfs_qm_shake_freelist(
+	int	howmany)
+{
+	int		nreclaimed = 0;
+	xfs_dquot_t	*dqp;
+
+	if (howmany <= 0)
+		return 0;
+
+	while (nreclaimed < howmany) {
+		dqp = xfs_qm_dqreclaim_one();
+		if (!dqp)
+			return nreclaimed;
+		xfs_qm_dqdestroy(dqp);
+		nreclaimed++;
+	}
+	return nreclaimed;
+}
+
+/*
+ * The kmem_shake interface is invoked when memory is running low.
+ */
+/* ARGSUSED */
+STATIC int
+xfs_qm_shake(
+	struct shrinker	*shrink,
+	struct shrink_control *sc)
+{
+	int	ndqused, nfree, n;
+	gfp_t gfp_mask = sc->gfp_mask;
+
+	if (!kmem_shake_allow(gfp_mask))
+		return 0;
+	if (!xfs_Gqm)
+		return 0;
+
+	nfree = xfs_Gqm->qm_dqfrlist_cnt; /* 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));
+}
+
+
+/*------------------------------------------------------------------*/
+
+/*
+ * 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;
+
+	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, 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 = 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 (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 = 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) &&
+		     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) {
+		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 : xfs_get_projid(ip)) ==
+				be32_to_cpu(gdqp->q_core.d_id));
+		xfs_trans_mod_dquot(tp, gdqp, XFS_TRANS_DQ_ICOUNT, 1);
+	}
+}
+