/*
   * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.

   * Copyright (C) 2004-2007 Red Hat, Inc.  All rights reserved.

   *
   * This copyrighted material is made available to anyone wishing to use,
   * modify, copy, or redistribute it subject to the terms and conditions

   * of the GNU General Public License version 2.

   */
  
  /*
   * Quota change tags are associated with each transaction that allocates or
   * deallocates space.  Those changes are accumulated locally to each node (in a
   * per-node file) and then are periodically synced to the quota file.  This
   * avoids the bottleneck of constantly touching the quota file, but introduces
   * fuzziness in the current usage value of IDs that are being used on different
   * nodes in the cluster simultaneously.  So, it is possible for a user on
   * multiple nodes to overrun their quota, but that overrun is controlable.

   * Since quota tags are part of transactions, there is no need for a quota check

   * program to be run on node crashes or anything like that.
   *
   * There are couple of knobs that let the administrator manage the quota
   * fuzziness.  "quota_quantum" sets the maximum time a quota change can be
   * sitting on one node before being synced to the quota file.  (The default is
   * 60 seconds.)  Another knob, "quota_scale" controls how quickly the frequency
   * of quota file syncs increases as the user moves closer to their limit.  The
   * more frequent the syncs, the more accurate the quota enforcement, but that
   * means that there is more contention between the nodes for the quota file.
   * The default value is one.  This sets the maximum theoretical quota overrun
   * (with infinite node with infinite bandwidth) to twice the user's limit.  (In
   * practice, the maximum overrun you see should be much less.)  A "quota_scale"
   * number greater than one makes quota syncs more frequent and reduces the
   * maximum overrun.  Numbers less than one (but greater than zero) make quota
   * syncs less frequent.
   *
   * GFS quotas also use per-ID Lock Value Blocks (LVBs) to cache the contents of
   * the quota file, so it is not being constantly read.
   */
  
  #include <linux/sched.h>
  #include <linux/slab.h>

  #include <linux/mm.h>

  #include <linux/spinlock.h>
  #include <linux/completion.h>
  #include <linux/buffer_head.h>

  #include <linux/sort.h>

  #include <linux/fs.h>

  #include <linux/bio.h>

  #include <linux/gfs2_ondisk.h>

  #include <linux/kthread.h>
  #include <linux/freezer.h>

  #include <linux/quota.h>

  #include <linux/dqblk_xfs.h>

  
  #include "gfs2.h"

  #include "incore.h"

  #include "bmap.h"
  #include "glock.h"
  #include "glops.h"

  #include "log.h"
  #include "meta_io.h"
  #include "quota.h"
  #include "rgrp.h"
  #include "super.h"
  #include "trans.h"

  #include "inode.h"

  #include "util.h"

  
  #define QUOTA_USER 1
  #define QUOTA_GROUP 0

  struct gfs2_quota_change_host {
  	u64 qc_change;
  	u32 qc_flags; /* GFS2_QCF_... */
  	u32 qc_id;
  };

  static LIST_HEAD(qd_lru_list);
  static atomic_t qd_lru_count = ATOMIC_INIT(0);

  static DEFINE_SPINLOCK(qd_lru_lock);

  int gfs2_shrink_qd_memory(struct shrinker *shrink, struct shrink_control *sc)

  {
  	struct gfs2_quota_data *qd;
  	struct gfs2_sbd *sdp;

  	int nr_to_scan = sc->nr_to_scan;

  	if (nr_to_scan == 0)

  		goto out;

  	if (!(sc->gfp_mask & __GFP_FS))

  		return -1;
  
  	spin_lock(&qd_lru_lock);

  	while (nr_to_scan && !list_empty(&qd_lru_list)) {

  		qd = list_entry(qd_lru_list.next,
  				struct gfs2_quota_data, qd_reclaim);
  		sdp = qd->qd_gl->gl_sbd;
  
  		/* Free from the filesystem-specific list */
  		list_del(&qd->qd_list);

  		gfs2_assert_warn(sdp, !qd->qd_change);
  		gfs2_assert_warn(sdp, !qd->qd_slot_count);
  		gfs2_assert_warn(sdp, !qd->qd_bh_count);

  		gfs2_glock_put(qd->qd_gl);

  		atomic_dec(&sdp->sd_quota_count);
  
  		/* Delete it from the common reclaim list */
  		list_del_init(&qd->qd_reclaim);
  		atomic_dec(&qd_lru_count);
  		spin_unlock(&qd_lru_lock);
  		kmem_cache_free(gfs2_quotad_cachep, qd);
  		spin_lock(&qd_lru_lock);

  		nr_to_scan--;

  	}
  	spin_unlock(&qd_lru_lock);
  
  out:
  	return (atomic_read(&qd_lru_count) * sysctl_vfs_cache_pressure) / 100;
  }

  static u64 qd2offset(struct gfs2_quota_data *qd)

  {

  	u64 offset;

  	offset = 2 * (u64)qd->qd_id + !test_bit(QDF_USER, &qd->qd_flags);

  	offset *= sizeof(struct gfs2_quota);
  
  	return offset;
  }

  static int qd_alloc(struct gfs2_sbd *sdp, int user, u32 id,

  		    struct gfs2_quota_data **qdp)
  {
  	struct gfs2_quota_data *qd;
  	int error;

  	qd = kmem_cache_zalloc(gfs2_quotad_cachep, GFP_NOFS);

  	if (!qd)
  		return -ENOMEM;

  	atomic_set(&qd->qd_count, 1);

  	qd->qd_id = id;
  	if (user)
  		set_bit(QDF_USER, &qd->qd_flags);
  	qd->qd_slot = -1;

  	INIT_LIST_HEAD(&qd->qd_reclaim);

  	error = gfs2_glock_get(sdp, 2 * (u64)id + !user,

  			      &gfs2_quota_glops, CREATE, &qd->qd_gl);
  	if (error)
  		goto fail;

  	*qdp = qd;
  
  	return 0;

  fail:

  	kmem_cache_free(gfs2_quotad_cachep, qd);

  	return error;
  }

  static int qd_get(struct gfs2_sbd *sdp, int user, u32 id,

  		  struct gfs2_quota_data **qdp)
  {
  	struct gfs2_quota_data *qd = NULL, *new_qd = NULL;
  	int error, found;
  
  	*qdp = NULL;
  
  	for (;;) {
  		found = 0;

  		spin_lock(&qd_lru_lock);

  		list_for_each_entry(qd, &sdp->sd_quota_list, qd_list) {
  			if (qd->qd_id == id &&
  			    !test_bit(QDF_USER, &qd->qd_flags) == !user) {

  				if (!atomic_read(&qd->qd_count) &&
  				    !list_empty(&qd->qd_reclaim)) {
  					/* Remove it from reclaim list */
  					list_del_init(&qd->qd_reclaim);
  					atomic_dec(&qd_lru_count);
  				}
  				atomic_inc(&qd->qd_count);

  				found = 1;
  				break;
  			}
  		}
  
  		if (!found)
  			qd = NULL;
  
  		if (!qd && new_qd) {
  			qd = new_qd;
  			list_add(&qd->qd_list, &sdp->sd_quota_list);
  			atomic_inc(&sdp->sd_quota_count);
  			new_qd = NULL;
  		}

  		spin_unlock(&qd_lru_lock);

  		if (qd) {

  			if (new_qd) {

  				gfs2_glock_put(new_qd->qd_gl);

  				kmem_cache_free(gfs2_quotad_cachep, new_qd);

  			}
  			*qdp = qd;
  			return 0;
  		}
  
  		error = qd_alloc(sdp, user, id, &new_qd);
  		if (error)
  			return error;
  	}
  }
  
  static void qd_hold(struct gfs2_quota_data *qd)
  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

  	gfs2_assert(sdp, atomic_read(&qd->qd_count));
  	atomic_inc(&qd->qd_count);

  }
  
  static void qd_put(struct gfs2_quota_data *qd)
  {

  	if (atomic_dec_and_lock(&qd->qd_count, &qd_lru_lock)) {
  		/* Add to the reclaim list */
  		list_add_tail(&qd->qd_reclaim, &qd_lru_list);
  		atomic_inc(&qd_lru_count);
  		spin_unlock(&qd_lru_lock);
  	}

  }
  
  static int slot_get(struct gfs2_quota_data *qd)
  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
  	unsigned int c, o = 0, b;
  	unsigned char byte = 0;

  	spin_lock(&qd_lru_lock);

  
  	if (qd->qd_slot_count++) {

  		spin_unlock(&qd_lru_lock);

  		return 0;
  	}
  
  	for (c = 0; c < sdp->sd_quota_chunks; c++)
  		for (o = 0; o < PAGE_SIZE; o++) {
  			byte = sdp->sd_quota_bitmap[c][o];
  			if (byte != 0xFF)
  				goto found;
  		}
  
  	goto fail;

  found:

  	for (b = 0; b < 8; b++)
  		if (!(byte & (1 << b)))
  			break;
  	qd->qd_slot = c * (8 * PAGE_SIZE) + o * 8 + b;
  
  	if (qd->qd_slot >= sdp->sd_quota_slots)
  		goto fail;
  
  	sdp->sd_quota_bitmap[c][o] |= 1 << b;

  	spin_unlock(&qd_lru_lock);

  
  	return 0;

  fail:

  	qd->qd_slot_count--;

  	spin_unlock(&qd_lru_lock);

  	return -ENOSPC;
  }
  
  static void slot_hold(struct gfs2_quota_data *qd)
  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

  	spin_lock(&qd_lru_lock);

  	gfs2_assert(sdp, qd->qd_slot_count);
  	qd->qd_slot_count++;

  	spin_unlock(&qd_lru_lock);

  }
  
  static void slot_put(struct gfs2_quota_data *qd)
  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

  	spin_lock(&qd_lru_lock);

  	gfs2_assert(sdp, qd->qd_slot_count);
  	if (!--qd->qd_slot_count) {
  		gfs2_icbit_munge(sdp, sdp->sd_quota_bitmap, qd->qd_slot, 0);
  		qd->qd_slot = -1;
  	}

  	spin_unlock(&qd_lru_lock);

  }
  
  static int bh_get(struct gfs2_quota_data *qd)
  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

  	struct gfs2_inode *ip = GFS2_I(sdp->sd_qc_inode);

  	unsigned int block, offset;

  	struct buffer_head *bh;
  	int error;

  	struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };

  	mutex_lock(&sdp->sd_quota_mutex);

  
  	if (qd->qd_bh_count++) {

  		mutex_unlock(&sdp->sd_quota_mutex);

  		return 0;
  	}
  
  	block = qd->qd_slot / sdp->sd_qc_per_block;

  	offset = qd->qd_slot % sdp->sd_qc_per_block;

  	bh_map.b_size = 1 << ip->i_inode.i_blkbits;

  	error = gfs2_block_map(&ip->i_inode, block, &bh_map, 0);

  	if (error)
  		goto fail;

  	error = gfs2_meta_read(ip->i_gl, bh_map.b_blocknr, DIO_WAIT, &bh);

  	if (error)
  		goto fail;
  	error = -EIO;
  	if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_QC))
  		goto fail_brelse;
  
  	qd->qd_bh = bh;
  	qd->qd_bh_qc = (struct gfs2_quota_change *)
  		(bh->b_data + sizeof(struct gfs2_meta_header) +
  		 offset * sizeof(struct gfs2_quota_change));

  	mutex_unlock(&sdp->sd_quota_mutex);

  
  	return 0;

  fail_brelse:

  	brelse(bh);

  fail:

  	qd->qd_bh_count--;

  	mutex_unlock(&sdp->sd_quota_mutex);

  	return error;
  }
  
  static void bh_put(struct gfs2_quota_data *qd)
  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

  	mutex_lock(&sdp->sd_quota_mutex);

  	gfs2_assert(sdp, qd->qd_bh_count);
  	if (!--qd->qd_bh_count) {
  		brelse(qd->qd_bh);
  		qd->qd_bh = NULL;
  		qd->qd_bh_qc = NULL;
  	}

  	mutex_unlock(&sdp->sd_quota_mutex);

  }
  
  static int qd_fish(struct gfs2_sbd *sdp, struct gfs2_quota_data **qdp)
  {
  	struct gfs2_quota_data *qd = NULL;
  	int error;
  	int found = 0;
  
  	*qdp = NULL;
  
  	if (sdp->sd_vfs->s_flags & MS_RDONLY)
  		return 0;

  	spin_lock(&qd_lru_lock);

  
  	list_for_each_entry(qd, &sdp->sd_quota_list, qd_list) {
  		if (test_bit(QDF_LOCKED, &qd->qd_flags) ||
  		    !test_bit(QDF_CHANGE, &qd->qd_flags) ||
  		    qd->qd_sync_gen >= sdp->sd_quota_sync_gen)
  			continue;
  
  		list_move_tail(&qd->qd_list, &sdp->sd_quota_list);
  
  		set_bit(QDF_LOCKED, &qd->qd_flags);

  		gfs2_assert_warn(sdp, atomic_read(&qd->qd_count));
  		atomic_inc(&qd->qd_count);

  		qd->qd_change_sync = qd->qd_change;
  		gfs2_assert_warn(sdp, qd->qd_slot_count);
  		qd->qd_slot_count++;
  		found = 1;
  
  		break;
  	}
  
  	if (!found)
  		qd = NULL;

  	spin_unlock(&qd_lru_lock);

  
  	if (qd) {
  		gfs2_assert_warn(sdp, qd->qd_change_sync);
  		error = bh_get(qd);
  		if (error) {
  			clear_bit(QDF_LOCKED, &qd->qd_flags);
  			slot_put(qd);
  			qd_put(qd);
  			return error;
  		}
  	}
  
  	*qdp = qd;
  
  	return 0;
  }
  
  static int qd_trylock(struct gfs2_quota_data *qd)
  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
  
  	if (sdp->sd_vfs->s_flags & MS_RDONLY)
  		return 0;

  	spin_lock(&qd_lru_lock);

  
  	if (test_bit(QDF_LOCKED, &qd->qd_flags) ||
  	    !test_bit(QDF_CHANGE, &qd->qd_flags)) {

  		spin_unlock(&qd_lru_lock);

  		return 0;
  	}
  
  	list_move_tail(&qd->qd_list, &sdp->sd_quota_list);
  
  	set_bit(QDF_LOCKED, &qd->qd_flags);

  	gfs2_assert_warn(sdp, atomic_read(&qd->qd_count));
  	atomic_inc(&qd->qd_count);

  	qd->qd_change_sync = qd->qd_change;
  	gfs2_assert_warn(sdp, qd->qd_slot_count);
  	qd->qd_slot_count++;

  	spin_unlock(&qd_lru_lock);

  
  	gfs2_assert_warn(sdp, qd->qd_change_sync);
  	if (bh_get(qd)) {
  		clear_bit(QDF_LOCKED, &qd->qd_flags);
  		slot_put(qd);
  		qd_put(qd);
  		return 0;
  	}
  
  	return 1;
  }
  
  static void qd_unlock(struct gfs2_quota_data *qd)
  {

  	gfs2_assert_warn(qd->qd_gl->gl_sbd,
  			 test_bit(QDF_LOCKED, &qd->qd_flags));

  	clear_bit(QDF_LOCKED, &qd->qd_flags);
  	bh_put(qd);
  	slot_put(qd);
  	qd_put(qd);
  }

  static int qdsb_get(struct gfs2_sbd *sdp, int user, u32 id,

  		    struct gfs2_quota_data **qdp)
  {
  	int error;

  	error = qd_get(sdp, user, id, qdp);

  	if (error)
  		return error;
  
  	error = slot_get(*qdp);
  	if (error)
  		goto fail;
  
  	error = bh_get(*qdp);
  	if (error)
  		goto fail_slot;
  
  	return 0;

  fail_slot:

  	slot_put(*qdp);

  fail:

  	qd_put(*qdp);
  	return error;
  }
  
  static void qdsb_put(struct gfs2_quota_data *qd)
  {
  	bh_put(qd);
  	slot_put(qd);
  	qd_put(qd);
  }

  int gfs2_quota_hold(struct gfs2_inode *ip, u32 uid, u32 gid)

  {

  	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

  	struct gfs2_qadata *qa = ip->i_qadata;
  	struct gfs2_quota_data **qd = qa->qa_qd;

  	int error;

  	if (gfs2_assert_warn(sdp, !qa->qa_qd_num) ||

  	    gfs2_assert_warn(sdp, !test_bit(GIF_QD_LOCKED, &ip->i_flags)))
  		return -EIO;
  
  	if (sdp->sd_args.ar_quota == GFS2_QUOTA_OFF)
  		return 0;

  	error = qdsb_get(sdp, QUOTA_USER, ip->i_inode.i_uid, qd);

  	if (error)
  		goto out;

  	qa->qa_qd_num++;

  	qd++;

  	error = qdsb_get(sdp, QUOTA_GROUP, ip->i_inode.i_gid, qd);

  	if (error)
  		goto out;

  	qa->qa_qd_num++;

  	qd++;

  	if (uid != NO_QUOTA_CHANGE && uid != ip->i_inode.i_uid) {

  		error = qdsb_get(sdp, QUOTA_USER, uid, qd);

  		if (error)
  			goto out;

  		qa->qa_qd_num++;

  		qd++;
  	}

  	if (gid != NO_QUOTA_CHANGE && gid != ip->i_inode.i_gid) {

  		error = qdsb_get(sdp, QUOTA_GROUP, gid, qd);

  		if (error)
  			goto out;

  		qa->qa_qd_num++;

  		qd++;
  	}

  out:

  	if (error)
  		gfs2_quota_unhold(ip);

  	return error;
  }
  
  void gfs2_quota_unhold(struct gfs2_inode *ip)
  {

  	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

  	struct gfs2_qadata *qa = ip->i_qadata;

  	unsigned int x;
  
  	gfs2_assert_warn(sdp, !test_bit(GIF_QD_LOCKED, &ip->i_flags));

  	for (x = 0; x < qa->qa_qd_num; x++) {
  		qdsb_put(qa->qa_qd[x]);
  		qa->qa_qd[x] = NULL;

  	}

  	qa->qa_qd_num = 0;

  }
  
  static int sort_qd(const void *a, const void *b)
  {

  	const struct gfs2_quota_data *qd_a = *(const struct gfs2_quota_data **)a;
  	const struct gfs2_quota_data *qd_b = *(const struct gfs2_quota_data **)b;

  
  	if (!test_bit(QDF_USER, &qd_a->qd_flags) !=
  	    !test_bit(QDF_USER, &qd_b->qd_flags)) {
  		if (test_bit(QDF_USER, &qd_a->qd_flags))

  			return -1;

  		else

  			return 1;

  	}

  	if (qd_a->qd_id < qd_b->qd_id)
  		return -1;
  	if (qd_a->qd_id > qd_b->qd_id)
  		return 1;

  	return 0;

  }

  static void do_qc(struct gfs2_quota_data *qd, s64 change)

  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

  	struct gfs2_inode *ip = GFS2_I(sdp->sd_qc_inode);

  	struct gfs2_quota_change *qc = qd->qd_bh_qc;

  	s64 x;

  	mutex_lock(&sdp->sd_quota_mutex);

  	gfs2_trans_add_bh(ip->i_gl, qd->qd_bh, 1);

  
  	if (!test_bit(QDF_CHANGE, &qd->qd_flags)) {
  		qc->qc_change = 0;
  		qc->qc_flags = 0;
  		if (test_bit(QDF_USER, &qd->qd_flags))
  			qc->qc_flags = cpu_to_be32(GFS2_QCF_USER);
  		qc->qc_id = cpu_to_be32(qd->qd_id);
  	}

  	x = be64_to_cpu(qc->qc_change) + change;

  	qc->qc_change = cpu_to_be64(x);

  	spin_lock(&qd_lru_lock);

  	qd->qd_change = x;

  	spin_unlock(&qd_lru_lock);

  
  	if (!x) {
  		gfs2_assert_warn(sdp, test_bit(QDF_CHANGE, &qd->qd_flags));
  		clear_bit(QDF_CHANGE, &qd->qd_flags);
  		qc->qc_flags = 0;
  		qc->qc_id = 0;
  		slot_put(qd);
  		qd_put(qd);
  	} else if (!test_and_set_bit(QDF_CHANGE, &qd->qd_flags)) {
  		qd_hold(qd);
  		slot_hold(qd);
  	}

  	mutex_unlock(&sdp->sd_quota_mutex);

  }

  /**

   * gfs2_adjust_quota - adjust record of current block usage
   * @ip: The quota inode
   * @loc: Offset of the entry in the quota file

   * @change: The amount of usage change to record

   * @qd: The quota data

   * @fdq: The updated limits to record

   *
   * This function was mostly borrowed from gfs2_block_truncate_page which was
   * in turn mostly borrowed from ext3

   *
   * Returns: 0 or -ve on error

   */

  static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,

  			     s64 change, struct gfs2_quota_data *qd,
  			     struct fs_disk_quota *fdq)

  {

  	struct inode *inode = &ip->i_inode;

  	struct gfs2_sbd *sdp = GFS2_SB(inode);

  	struct address_space *mapping = inode->i_mapping;
  	unsigned long index = loc >> PAGE_CACHE_SHIFT;

  	unsigned offset = loc & (PAGE_CACHE_SIZE - 1);

  	unsigned blocksize, iblock, pos;

  	struct buffer_head *bh;

  	struct page *page;

  	void *kaddr, *ptr;
  	struct gfs2_quota q, *qp;
  	int err, nbytes;

  	u64 size;

  	if (gfs2_is_stuffed(ip)) {
  		err = gfs2_unstuff_dinode(ip, NULL);
  		if (err)
  			return err;
  	}

  
  	memset(&q, 0, sizeof(struct gfs2_quota));
  	err = gfs2_internal_read(ip, NULL, (char *)&q, &loc, sizeof(q));
  	if (err < 0)
  		return err;
  
  	err = -EIO;
  	qp = &q;
  	qp->qu_value = be64_to_cpu(qp->qu_value);
  	qp->qu_value += change;
  	qp->qu_value = cpu_to_be64(qp->qu_value);
  	qd->qd_qb.qb_value = qp->qu_value;
  	if (fdq) {
  		if (fdq->d_fieldmask & FS_DQ_BSOFT) {

  			qp->qu_warn = cpu_to_be64(fdq->d_blk_softlimit >> sdp->sd_fsb2bb_shift);

  			qd->qd_qb.qb_warn = qp->qu_warn;
  		}
  		if (fdq->d_fieldmask & FS_DQ_BHARD) {

  			qp->qu_limit = cpu_to_be64(fdq->d_blk_hardlimit >> sdp->sd_fsb2bb_shift);

  			qd->qd_qb.qb_limit = qp->qu_limit;
  		}

  		if (fdq->d_fieldmask & FS_DQ_BCOUNT) {
  			qp->qu_value = cpu_to_be64(fdq->d_bcount >> sdp->sd_fsb2bb_shift);
  			qd->qd_qb.qb_value = qp->qu_value;
  		}

  	}
  
  	/* Write the quota into the quota file on disk */
  	ptr = qp;
  	nbytes = sizeof(struct gfs2_quota);
  get_a_page:

  	page = grab_cache_page(mapping, index);
  	if (!page)
  		return -ENOMEM;
  
  	blocksize = inode->i_sb->s_blocksize;
  	iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
  
  	if (!page_has_buffers(page))
  		create_empty_buffers(page, blocksize, 0);
  
  	bh = page_buffers(page);
  	pos = blocksize;
  	while (offset >= pos) {
  		bh = bh->b_this_page;
  		iblock++;
  		pos += blocksize;
  	}
  
  	if (!buffer_mapped(bh)) {

  		gfs2_block_map(inode, iblock, bh, 1);

  		if (!buffer_mapped(bh))

  			goto unlock_out;
  		/* If it's a newly allocated disk block for quota, zero it */

  		if (buffer_new(bh))
  			zero_user(page, pos - blocksize, bh->b_size);

  	}
  
  	if (PageUptodate(page))
  		set_buffer_uptodate(bh);
  
  	if (!buffer_uptodate(bh)) {

  		ll_rw_block(READ | REQ_META, 1, &bh);

  		wait_on_buffer(bh);
  		if (!buffer_uptodate(bh))

  			goto unlock_out;

  	}
  
  	gfs2_trans_add_bh(ip->i_gl, bh, 0);
  
  	kaddr = kmap_atomic(page, KM_USER0);

  	if (offset + sizeof(struct gfs2_quota) > PAGE_CACHE_SIZE)
  		nbytes = PAGE_CACHE_SIZE - offset;
  	memcpy(kaddr + offset, ptr, nbytes);

  	flush_dcache_page(page);
  	kunmap_atomic(kaddr, KM_USER0);

  	unlock_page(page);
  	page_cache_release(page);
  
  	/* If quota straddles page boundary, we need to update the rest of the
  	 * quota at the beginning of the next page */

  	if ((offset + sizeof(struct gfs2_quota)) > PAGE_CACHE_SIZE) {

  		ptr = ptr + nbytes;
  		nbytes = sizeof(struct gfs2_quota) - nbytes;
  		offset = 0;
  		index++;
  		goto get_a_page;
  	}

  	size = loc + sizeof(struct gfs2_quota);

  	if (size > inode->i_size)

  		i_size_write(inode, size);

  	inode->i_mtime = inode->i_atime = CURRENT_TIME;

  	mark_inode_dirty(inode);

  	return err;

  unlock_out:

  	unlock_page(page);
  	page_cache_release(page);
  	return err;
  }

  static int do_sync(unsigned int num_qd, struct gfs2_quota_data **qda)
  {
  	struct gfs2_sbd *sdp = (*qda)->qd_gl->gl_sbd;

  	struct gfs2_inode *ip = GFS2_I(sdp->sd_quota_inode);

  	unsigned int data_blocks, ind_blocks;
  	struct gfs2_holder *ghs, i_gh;
  	unsigned int qx, x;
  	struct gfs2_quota_data *qd;

  	loff_t offset;

  	unsigned int nalloc = 0, blocks;

  	int error;
  
  	gfs2_write_calc_reserv(ip, sizeof(struct gfs2_quota),
  			      &data_blocks, &ind_blocks);

  	ghs = kcalloc(num_qd, sizeof(struct gfs2_holder), GFP_NOFS);

  	if (!ghs)
  		return -ENOMEM;
  
  	sort(qda, num_qd, sizeof(struct gfs2_quota_data *), sort_qd, NULL);

  	mutex_lock_nested(&ip->i_inode.i_mutex, I_MUTEX_QUOTA);

  	for (qx = 0; qx < num_qd; qx++) {

  		error = gfs2_glock_nq_init(qda[qx]->qd_gl, LM_ST_EXCLUSIVE,

  					   GL_NOCACHE, &ghs[qx]);
  		if (error)
  			goto out;
  	}
  
  	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
  	if (error)
  		goto out;
  
  	for (x = 0; x < num_qd; x++) {

  		offset = qd2offset(qda[x]);

  		if (gfs2_write_alloc_required(ip, offset,
  					      sizeof(struct gfs2_quota)))

  			nalloc++;
  	}

  	/* 
  	 * 1 blk for unstuffing inode if stuffed. We add this extra
  	 * block to the reservation unconditionally. If the inode
  	 * doesn't need unstuffing, the block will be released to the 
  	 * rgrp since it won't be allocated during the transaction
  	 */

  	/* +3 in the end for unstuffing block, inode size update block
  	 * and another block in case quota straddles page boundary and 
  	 * two blocks need to be updated instead of 1 */
  	blocks = num_qd * data_blocks + RES_DINODE + num_qd + 3;

  	error = gfs2_inplace_reserve(ip, 1 +
  				     (nalloc * (data_blocks + ind_blocks)));

  	if (error)
  		goto out_alloc;

  	if (nalloc)

  		blocks += gfs2_rg_blocks(ip) + nalloc * ind_blocks + RES_STATFS;

  
  	error = gfs2_trans_begin(sdp, blocks, 0);
  	if (error)
  		goto out_ipres;

  
  	for (x = 0; x < num_qd; x++) {

  		qd = qda[x];
  		offset = qd2offset(qd);

  		error = gfs2_adjust_quota(ip, offset, qd->qd_change_sync, qd, NULL);

  		if (error)

  			goto out_end_trans;

  
  		do_qc(qd, -qd->qd_change_sync);

  		set_bit(QDF_REFRESH, &qd->qd_flags);

  	}
  
  	error = 0;

  out_end_trans:

  	gfs2_trans_end(sdp);

  out_ipres:

  	gfs2_inplace_release(ip);

  out_alloc:

  	gfs2_glock_dq_uninit(&i_gh);

  out:

  	while (qx--)
  		gfs2_glock_dq_uninit(&ghs[qx]);

  	mutex_unlock(&ip->i_inode.i_mutex);

  	kfree(ghs);

  	gfs2_log_flush(ip->i_gl->gl_sbd, ip->i_gl);

  	return error;
  }

  static int update_qd(struct gfs2_sbd *sdp, struct gfs2_quota_data *qd)
  {
  	struct gfs2_inode *ip = GFS2_I(sdp->sd_quota_inode);
  	struct gfs2_quota q;
  	struct gfs2_quota_lvb *qlvb;
  	loff_t pos;
  	int error;
  
  	memset(&q, 0, sizeof(struct gfs2_quota));
  	pos = qd2offset(qd);
  	error = gfs2_internal_read(ip, NULL, (char *)&q, &pos, sizeof(q));
  	if (error < 0)
  		return error;
  
  	qlvb = (struct gfs2_quota_lvb *)qd->qd_gl->gl_lvb;
  	qlvb->qb_magic = cpu_to_be32(GFS2_MAGIC);
  	qlvb->__pad = 0;
  	qlvb->qb_limit = q.qu_limit;
  	qlvb->qb_warn = q.qu_warn;
  	qlvb->qb_value = q.qu_value;
  	qd->qd_qb = *qlvb;
  
  	return 0;
  }

  static int do_glock(struct gfs2_quota_data *qd, int force_refresh,
  		    struct gfs2_holder *q_gh)
  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

  	struct gfs2_inode *ip = GFS2_I(sdp->sd_quota_inode);

  	struct gfs2_holder i_gh;

  	int error;

  restart:

  	error = gfs2_glock_nq_init(qd->qd_gl, LM_ST_SHARED, 0, q_gh);
  	if (error)
  		return error;

  	qd->qd_qb = *(struct gfs2_quota_lvb *)qd->qd_gl->gl_lvb;

  	if (force_refresh || qd->qd_qb.qb_magic != cpu_to_be32(GFS2_MAGIC)) {

  		gfs2_glock_dq_uninit(q_gh);

  		error = gfs2_glock_nq_init(qd->qd_gl, LM_ST_EXCLUSIVE,
  					   GL_NOCACHE, q_gh);

  		if (error)
  			return error;

  		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &i_gh);

  		if (error)
  			goto fail;

  		error = update_qd(sdp, qd);
  		if (error)

  			goto fail_gunlock;

  		gfs2_glock_dq_uninit(&i_gh);

  		gfs2_glock_dq_uninit(q_gh);
  		force_refresh = 0;
  		goto restart;

  	}
  
  	return 0;

  fail_gunlock:

  	gfs2_glock_dq_uninit(&i_gh);

  fail:

  	gfs2_glock_dq_uninit(q_gh);

  	return error;
  }

  int gfs2_quota_lock(struct gfs2_inode *ip, u32 uid, u32 gid)

  {

  	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

  	struct gfs2_qadata *qa = ip->i_qadata;

  	struct gfs2_quota_data *qd;

  	unsigned int x;
  	int error = 0;

  	error = gfs2_quota_hold(ip, uid, gid);
  	if (error)
  		return error;

  
  	if (capable(CAP_SYS_RESOURCE) ||
  	    sdp->sd_args.ar_quota != GFS2_QUOTA_ON)
  		return 0;

  	sort(qa->qa_qd, qa->qa_qd_num, sizeof(struct gfs2_quota_data *),

  	     sort_qd, NULL);

  	for (x = 0; x < qa->qa_qd_num; x++) {

  		int force = NO_FORCE;

  		qd = qa->qa_qd[x];

  		if (test_and_clear_bit(QDF_REFRESH, &qd->qd_flags))
  			force = FORCE;

  		error = do_glock(qd, force, &qa->qa_qd_ghs[x]);

  		if (error)
  			break;
  	}
  
  	if (!error)
  		set_bit(GIF_QD_LOCKED, &ip->i_flags);
  	else {
  		while (x--)

  			gfs2_glock_dq_uninit(&qa->qa_qd_ghs[x]);

  		gfs2_quota_unhold(ip);
  	}
  
  	return error;
  }
  
  static int need_sync(struct gfs2_quota_data *qd)
  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
  	struct gfs2_tune *gt = &sdp->sd_tune;

  	s64 value;

  	unsigned int num, den;
  	int do_sync = 1;
  
  	if (!qd->qd_qb.qb_limit)
  		return 0;

  	spin_lock(&qd_lru_lock);

  	value = qd->qd_change;

  	spin_unlock(&qd_lru_lock);

  
  	spin_lock(&gt->gt_spin);
  	num = gt->gt_quota_scale_num;
  	den = gt->gt_quota_scale_den;
  	spin_unlock(&gt->gt_spin);
  
  	if (value < 0)
  		do_sync = 0;

  	else if ((s64)be64_to_cpu(qd->qd_qb.qb_value) >=
  		 (s64)be64_to_cpu(qd->qd_qb.qb_limit))

  		do_sync = 0;
  	else {
  		value *= gfs2_jindex_size(sdp) * num;

  		value = div_s64(value, den);

  		value += (s64)be64_to_cpu(qd->qd_qb.qb_value);

  		if (value < (s64)be64_to_cpu(qd->qd_qb.qb_limit))

  			do_sync = 0;
  	}
  
  	return do_sync;
  }
  
  void gfs2_quota_unlock(struct gfs2_inode *ip)
  {

  	struct gfs2_qadata *qa = ip->i_qadata;

  	struct gfs2_quota_data *qda[4];
  	unsigned int count = 0;
  	unsigned int x;
  
  	if (!test_and_clear_bit(GIF_QD_LOCKED, &ip->i_flags))
  		goto out;

  	for (x = 0; x < qa->qa_qd_num; x++) {

  		struct gfs2_quota_data *qd;
  		int sync;

  		qd = qa->qa_qd[x];

  		sync = need_sync(qd);

  		gfs2_glock_dq_uninit(&qa->qa_qd_ghs[x]);

  
  		if (sync && qd_trylock(qd))
  			qda[count++] = qd;
  	}
  
  	if (count) {
  		do_sync(count, qda);
  		for (x = 0; x < count; x++)
  			qd_unlock(qda[x]);
  	}

  out:

  	gfs2_quota_unhold(ip);
  }
  
  #define MAX_LINE 256
  
  static int print_message(struct gfs2_quota_data *qd, char *type)
  {
  	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

  	printk(KERN_INFO "GFS2: fsid=%s: quota %s for %s %u
  ",

  	       sdp->sd_fsname, type,
  	       (test_bit(QDF_USER, &qd->qd_flags)) ? "user" : "group",
  	       qd->qd_id);

  
  	return 0;
  }

  int gfs2_quota_check(struct gfs2_inode *ip, u32 uid, u32 gid)

  {

  	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

  	struct gfs2_qadata *qa = ip->i_qadata;

  	struct gfs2_quota_data *qd;

  	s64 value;

  	unsigned int x;
  	int error = 0;
  
  	if (!test_bit(GIF_QD_LOCKED, &ip->i_flags))
  		return 0;
  
          if (sdp->sd_args.ar_quota != GFS2_QUOTA_ON)
                  return 0;

  	for (x = 0; x < qa->qa_qd_num; x++) {
  		qd = qa->qa_qd[x];

  
  		if (!((qd->qd_id == uid && test_bit(QDF_USER, &qd->qd_flags)) ||
  		      (qd->qd_id == gid && !test_bit(QDF_USER, &qd->qd_flags))))
  			continue;

  		value = (s64)be64_to_cpu(qd->qd_qb.qb_value);

  		spin_lock(&qd_lru_lock);

  		value += qd->qd_change;

  		spin_unlock(&qd_lru_lock);

  		if (be64_to_cpu(qd->qd_qb.qb_limit) && (s64)be64_to_cpu(qd->qd_qb.qb_limit) < value) {

  			print_message(qd, "exceeded");

  			quota_send_warning(test_bit(QDF_USER, &qd->qd_flags) ?
  					   USRQUOTA : GRPQUOTA, qd->qd_id,
  					   sdp->sd_vfs->s_dev, QUOTA_NL_BHARDWARN);

  			error = -EDQUOT;
  			break;

  		} else if (be64_to_cpu(qd->qd_qb.qb_warn) &&

  			   (s64)be64_to_cpu(qd->qd_qb.qb_warn) < value &&

  			   time_after_eq(jiffies, qd->qd_last_warn +

  					 gfs2_tune_get(sdp,
  						gt_quota_warn_period) * HZ)) {

  			quota_send_warning(test_bit(QDF_USER, &qd->qd_flags) ?
  					   USRQUOTA : GRPQUOTA, qd->qd_id,
  					   sdp->sd_vfs->s_dev, QUOTA_NL_BSOFTWARN);

  			error = print_message(qd, "warning");
  			qd->qd_last_warn = jiffies;
  		}
  	}
  
  	return error;
  }

  void gfs2_quota_change(struct gfs2_inode *ip, s64 change,
  		       u32 uid, u32 gid)

  {

  	struct gfs2_qadata *qa = ip->i_qadata;

  	struct gfs2_quota_data *qd;
  	unsigned int x;

  	if (gfs2_assert_warn(GFS2_SB(&ip->i_inode), change))

  		return;

  	if (ip->i_diskflags & GFS2_DIF_SYSTEM)

  		return;

  	for (x = 0; x < qa->qa_qd_num; x++) {
  		qd = qa->qa_qd[x];

  
  		if ((qd->qd_id == uid && test_bit(QDF_USER, &qd->qd_flags)) ||
  		    (qd->qd_id == gid && !test_bit(QDF_USER, &qd->qd_flags))) {
  			do_qc(qd, change);

  		}
  	}
  }

  int gfs2_quota_sync(struct super_block *sb, int type, int wait)

  {

  	struct gfs2_sbd *sdp = sb->s_fs_info;

  	struct gfs2_quota_data **qda;
  	unsigned int max_qd = gfs2_tune_get(sdp, gt_quota_simul_sync);
  	unsigned int num_qd;
  	unsigned int x;
  	int error = 0;
  
  	sdp->sd_quota_sync_gen++;
  
  	qda = kcalloc(max_qd, sizeof(struct gfs2_quota_data *), GFP_KERNEL);
  	if (!qda)
  		return -ENOMEM;
  
  	do {
  		num_qd = 0;
  
  		for (;;) {
  			error = qd_fish(sdp, qda + num_qd);
  			if (error || !qda[num_qd])
  				break;
  			if (++num_qd == max_qd)
  				break;
  		}
  
  		if (num_qd) {
  			if (!error)
  				error = do_sync(num_qd, qda);
  			if (!error)
  				for (x = 0; x < num_qd; x++)
  					qda[x]->qd_sync_gen =
  						sdp->sd_quota_sync_gen;
  
  			for (x = 0; x < num_qd; x++)
  				qd_unlock(qda[x]);
  		}
  	} while (!error && num_qd == max_qd);
  
  	kfree(qda);
  
  	return error;
  }

  static int gfs2_quota_sync_timeo(struct super_block *sb, int type)
  {
  	return gfs2_quota_sync(sb, type, 0);
  }

  int gfs2_quota_refresh(struct gfs2_sbd *sdp, int user, u32 id)

  {
  	struct gfs2_quota_data *qd;
  	struct gfs2_holder q_gh;
  	int error;

  	error = qd_get(sdp, user, id, &qd);

  	if (error)
  		return error;
  
  	error = do_glock(qd, FORCE, &q_gh);
  	if (!error)
  		gfs2_glock_dq_uninit(&q_gh);
  
  	qd_put(qd);

  	return error;
  }

  static void gfs2_quota_change_in(struct gfs2_quota_change_host *qc, const void *buf)
  {
  	const struct gfs2_quota_change *str = buf;
  
  	qc->qc_change = be64_to_cpu(str->qc_change);
  	qc->qc_flags = be32_to_cpu(str->qc_flags);
  	qc->qc_id = be32_to_cpu(str->qc_id);
  }

  int gfs2_quota_init(struct gfs2_sbd *sdp)
  {

  	struct gfs2_inode *ip = GFS2_I(sdp->sd_qc_inode);

  	u64 size = i_size_read(sdp->sd_qc_inode);
  	unsigned int blocks = size >> sdp->sd_sb.sb_bsize_shift;

  	unsigned int x, slot = 0;
  	unsigned int found = 0;

  	u64 dblock;
  	u32 extlen = 0;

  	int error;

  	if (gfs2_check_internal_file_size(sdp->sd_qc_inode, 1, 64 << 20))

  		return -EIO;

  	sdp->sd_quota_slots = blocks * sdp->sd_qc_per_block;

  	sdp->sd_quota_chunks = DIV_ROUND_UP(sdp->sd_quota_slots, 8 * PAGE_SIZE);

  
  	error = -ENOMEM;
  
  	sdp->sd_quota_bitmap = kcalloc(sdp->sd_quota_chunks,

  				       sizeof(unsigned char *), GFP_NOFS);

  	if (!sdp->sd_quota_bitmap)
  		return error;
  
  	for (x = 0; x < sdp->sd_quota_chunks; x++) {

  		sdp->sd_quota_bitmap[x] = kzalloc(PAGE_SIZE, GFP_NOFS);

  		if (!sdp->sd_quota_bitmap[x])
  			goto fail;
  	}
  
  	for (x = 0; x < blocks; x++) {
  		struct buffer_head *bh;
  		unsigned int y;
  
  		if (!extlen) {
  			int new = 0;

  			error = gfs2_extent_map(&ip->i_inode, x, &new, &dblock, &extlen);

  			if (error)
  				goto fail;
  		}

  		error = -EIO;

  		bh = gfs2_meta_ra(ip->i_gl, dblock, extlen);
  		if (!bh)
  			goto fail;

  		if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_QC)) {
  			brelse(bh);
  			goto fail;
  		}

  		for (y = 0; y < sdp->sd_qc_per_block && slot < sdp->sd_quota_slots;

  		     y++, slot++) {

  			struct gfs2_quota_change_host qc;

  			struct gfs2_quota_data *qd;
  
  			gfs2_quota_change_in(&qc, bh->b_data +
  					  sizeof(struct gfs2_meta_header) +
  					  y * sizeof(struct gfs2_quota_change));
  			if (!qc.qc_change)
  				continue;
  
  			error = qd_alloc(sdp, (qc.qc_flags & GFS2_QCF_USER),
  					 qc.qc_id, &qd);
  			if (error) {
  				brelse(bh);
  				goto fail;
  			}
  
  			set_bit(QDF_CHANGE, &qd->qd_flags);
  			qd->qd_change = qc.qc_change;
  			qd->qd_slot = slot;
  			qd->qd_slot_count = 1;

  			spin_lock(&qd_lru_lock);

  			gfs2_icbit_munge(sdp, sdp->sd_quota_bitmap, slot, 1);
  			list_add(&qd->qd_list, &sdp->sd_quota_list);
  			atomic_inc(&sdp->sd_quota_count);

  			spin_unlock(&qd_lru_lock);

  
  			found++;
  		}
  
  		brelse(bh);
  		dblock++;
  		extlen--;
  	}
  
  	if (found)
  		fs_info(sdp, "found %u quota changes
  ", found);
  
  	return 0;

  fail:

  	gfs2_quota_cleanup(sdp);
  	return error;
  }

  void gfs2_quota_cleanup(struct gfs2_sbd *sdp)
  {
  	struct list_head *head = &sdp->sd_quota_list;
  	struct gfs2_quota_data *qd;
  	unsigned int x;

  	spin_lock(&qd_lru_lock);

  	while (!list_empty(head)) {
  		qd = list_entry(head->prev, struct gfs2_quota_data, qd_list);

  		if (atomic_read(&qd->qd_count) > 1 ||
  		    (atomic_read(&qd->qd_count) &&
  		     !test_bit(QDF_CHANGE, &qd->qd_flags))) {

  			list_move(&qd->qd_list, head);
  			spin_unlock(&qd_lru_lock);

  			schedule();

  			spin_lock(&qd_lru_lock);

  			continue;
  		}
  
  		list_del(&qd->qd_list);

  		/* Also remove if this qd exists in the reclaim list */
  		if (!list_empty(&qd->qd_reclaim)) {
  			list_del_init(&qd->qd_reclaim);
  			atomic_dec(&qd_lru_count);
  		}

  		atomic_dec(&sdp->sd_quota_count);

  		spin_unlock(&qd_lru_lock);

  		if (!atomic_read(&qd->qd_count)) {

  			gfs2_assert_warn(sdp, !qd->qd_change);
  			gfs2_assert_warn(sdp, !qd->qd_slot_count);
  		} else
  			gfs2_assert_warn(sdp, qd->qd_slot_count == 1);
  		gfs2_assert_warn(sdp, !qd->qd_bh_count);

  		gfs2_glock_put(qd->qd_gl);

  		kmem_cache_free(gfs2_quotad_cachep, qd);

  		spin_lock(&qd_lru_lock);

  	}

  	spin_unlock(&qd_lru_lock);

  
  	gfs2_assert_warn(sdp, !atomic_read(&sdp->sd_quota_count));
  
  	if (sdp->sd_quota_bitmap) {
  		for (x = 0; x < sdp->sd_quota_chunks; x++)
  			kfree(sdp->sd_quota_bitmap[x]);
  		kfree(sdp->sd_quota_bitmap);
  	}
  }

  static void quotad_error(struct gfs2_sbd *sdp, const char *msg, int error)
  {
  	if (error == 0 || error == -EROFS)
  		return;
  	if (!test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
  		fs_err(sdp, "gfs2_quotad: %s error %d
  ", msg, error);
  }
  
  static void quotad_check_timeo(struct gfs2_sbd *sdp, const char *msg,

  			       int (*fxn)(struct super_block *sb, int type),

  			       unsigned long t, unsigned long *timeo,
  			       unsigned int *new_timeo)
  {
  	if (t >= *timeo) {

  		int error = fxn(sdp->sd_vfs, 0);

  		quotad_error(sdp, msg, error);
  		*timeo = gfs2_tune_get_i(&sdp->sd_tune, new_timeo) * HZ;
  	} else {
  		*timeo -= t;
  	}
  }

  static void quotad_check_trunc_list(struct gfs2_sbd *sdp)
  {
  	struct gfs2_inode *ip;
  
  	while(1) {
  		ip = NULL;
  		spin_lock(&sdp->sd_trunc_lock);
  		if (!list_empty(&sdp->sd_trunc_list)) {
  			ip = list_entry(sdp->sd_trunc_list.next,
  					struct gfs2_inode, i_trunc_list);
  			list_del_init(&ip->i_trunc_list);
  		}
  		spin_unlock(&sdp->sd_trunc_lock);
  		if (ip == NULL)
  			return;
  		gfs2_glock_finish_truncate(ip);
  	}
  }

  void gfs2_wake_up_statfs(struct gfs2_sbd *sdp) {
  	if (!sdp->sd_statfs_force_sync) {
  		sdp->sd_statfs_force_sync = 1;
  		wake_up(&sdp->sd_quota_wait);
  	}
  }

  /**
   * gfs2_quotad - Write cached quota changes into the quota file
   * @sdp: Pointer to GFS2 superblock
   *
   */
  
  int gfs2_quotad(void *data)
  {
  	struct gfs2_sbd *sdp = data;
  	struct gfs2_tune *tune = &sdp->sd_tune;
  	unsigned long statfs_timeo = 0;
  	unsigned long quotad_timeo = 0;
  	unsigned long t = 0;
  	DEFINE_WAIT(wait);

  	int empty;

  
  	while (!kthread_should_stop()) {
  
  		/* Update the master statfs file */

  		if (sdp->sd_statfs_force_sync) {
  			int error = gfs2_statfs_sync(sdp->sd_vfs, 0);
  			quotad_error(sdp, "statfs", error);
  			statfs_timeo = gfs2_tune_get(sdp, gt_statfs_quantum) * HZ;
  		}
  		else
  			quotad_check_timeo(sdp, "statfs", gfs2_statfs_sync, t,
  				   	   &statfs_timeo,
  					   &tune->gt_statfs_quantum);

  
  		/* Update quota file */

  		quotad_check_timeo(sdp, "sync", gfs2_quota_sync_timeo, t,

  				   &quotad_timeo, &tune->gt_quota_quantum);

  		/* Check for & recover partially truncated inodes */
  		quotad_check_trunc_list(sdp);

  		try_to_freeze();

  		t = min(quotad_timeo, statfs_timeo);

  		prepare_to_wait(&sdp->sd_quota_wait, &wait, TASK_INTERRUPTIBLE);

  		spin_lock(&sdp->sd_trunc_lock);
  		empty = list_empty(&sdp->sd_trunc_list);
  		spin_unlock(&sdp->sd_trunc_lock);

  		if (empty && !sdp->sd_statfs_force_sync)

  			t -= schedule_timeout(t);
  		else
  			t = 0;

  		finish_wait(&sdp->sd_quota_wait, &wait);
  	}
  
  	return 0;
  }

  static int gfs2_quota_get_xstate(struct super_block *sb,
  				 struct fs_quota_stat *fqs)
  {
  	struct gfs2_sbd *sdp = sb->s_fs_info;
  
  	memset(fqs, 0, sizeof(struct fs_quota_stat));
  	fqs->qs_version = FS_QSTAT_VERSION;

  
  	switch (sdp->sd_args.ar_quota) {
  	case GFS2_QUOTA_ON:

  		fqs->qs_flags |= (FS_QUOTA_UDQ_ENFD | FS_QUOTA_GDQ_ENFD);

  		/*FALLTHRU*/
  	case GFS2_QUOTA_ACCOUNT:

  		fqs->qs_flags |= (FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT);

  		break;
  	case GFS2_QUOTA_OFF:
  		break;
  	}

  	if (sdp->sd_quota_inode) {
  		fqs->qs_uquota.qfs_ino = GFS2_I(sdp->sd_quota_inode)->i_no_addr;
  		fqs->qs_uquota.qfs_nblks = sdp->sd_quota_inode->i_blocks;
  	}
  	fqs->qs_uquota.qfs_nextents = 1; /* unsupported */
  	fqs->qs_gquota = fqs->qs_uquota; /* its the same inode in both cases */
  	fqs->qs_incoredqs = atomic_read(&qd_lru_count);
  	return 0;
  }

  static int gfs2_get_dqblk(struct super_block *sb, int type, qid_t id,
  			  struct fs_disk_quota *fdq)

  {
  	struct gfs2_sbd *sdp = sb->s_fs_info;
  	struct gfs2_quota_lvb *qlvb;
  	struct gfs2_quota_data *qd;
  	struct gfs2_holder q_gh;
  	int error;
  
  	memset(fdq, 0, sizeof(struct fs_disk_quota));
  
  	if (sdp->sd_args.ar_quota == GFS2_QUOTA_OFF)
  		return -ESRCH; /* Crazy XFS error code */
  
  	if (type == USRQUOTA)
  		type = QUOTA_USER;
  	else if (type == GRPQUOTA)
  		type = QUOTA_GROUP;
  	else
  		return -EINVAL;
  
  	error = qd_get(sdp, type, id, &qd);
  	if (error)
  		return error;
  	error = do_glock(qd, FORCE, &q_gh);
  	if (error)
  		goto out;
  
  	qlvb = (struct gfs2_quota_lvb *)qd->qd_gl->gl_lvb;
  	fdq->d_version = FS_DQUOT_VERSION;

  	fdq->d_flags = (type == QUOTA_USER) ? FS_USER_QUOTA : FS_GROUP_QUOTA;

  	fdq->d_id = id;

  	fdq->d_blk_hardlimit = be64_to_cpu(qlvb->qb_limit) << sdp->sd_fsb2bb_shift;
  	fdq->d_blk_softlimit = be64_to_cpu(qlvb->qb_warn) << sdp->sd_fsb2bb_shift;
  	fdq->d_bcount = be64_to_cpu(qlvb->qb_value) << sdp->sd_fsb2bb_shift;

  
  	gfs2_glock_dq_uninit(&q_gh);
  out:
  	qd_put(qd);
  	return error;
  }

  /* GFS2 only supports a subset of the XFS fields */

  #define GFS2_FIELDMASK (FS_DQ_BSOFT|FS_DQ_BHARD|FS_DQ_BCOUNT)

  static int gfs2_set_dqblk(struct super_block *sb, int type, qid_t id,
  			  struct fs_disk_quota *fdq)

  {
  	struct gfs2_sbd *sdp = sb->s_fs_info;
  	struct gfs2_inode *ip = GFS2_I(sdp->sd_quota_inode);
  	struct gfs2_quota_data *qd;
  	struct gfs2_holder q_gh, i_gh;
  	unsigned int data_blocks, ind_blocks;
  	unsigned int blocks = 0;
  	int alloc_required;

  	loff_t offset;
  	int error;
  
  	if (sdp->sd_args.ar_quota == GFS2_QUOTA_OFF)
  		return -ESRCH; /* Crazy XFS error code */
  
  	switch(type) {
  	case USRQUOTA:
  		type = QUOTA_USER;

  		if (fdq->d_flags != FS_USER_QUOTA)

  			return -EINVAL;
  		break;
  	case GRPQUOTA:
  		type = QUOTA_GROUP;

  		if (fdq->d_flags != FS_GROUP_QUOTA)

  			return -EINVAL;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	if (fdq->d_fieldmask & ~GFS2_FIELDMASK)
  		return -EINVAL;
  	if (fdq->d_id != id)
  		return -EINVAL;
  
  	error = qd_get(sdp, type, id, &qd);
  	if (error)
  		return error;
  
  	mutex_lock(&ip->i_inode.i_mutex);
  	error = gfs2_glock_nq_init(qd->qd_gl, LM_ST_EXCLUSIVE, 0, &q_gh);
  	if (error)
  		goto out_put;
  	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
  	if (error)
  		goto out_q;
  
  	/* Check for existing entry, if none then alloc new blocks */
  	error = update_qd(sdp, qd);
  	if (error)
  		goto out_i;
  
  	/* If nothing has changed, this is a no-op */
  	if ((fdq->d_fieldmask & FS_DQ_BSOFT) &&

  	    ((fdq->d_blk_softlimit >> sdp->sd_fsb2bb_shift) == be64_to_cpu(qd->qd_qb.qb_warn)))

  		fdq->d_fieldmask ^= FS_DQ_BSOFT;

  	if ((fdq->d_fieldmask & FS_DQ_BHARD) &&

  	    ((fdq->d_blk_hardlimit >> sdp->sd_fsb2bb_shift) == be64_to_cpu(qd->qd_qb.qb_limit)))

  		fdq->d_fieldmask ^= FS_DQ_BHARD;

  
  	if ((fdq->d_fieldmask & FS_DQ_BCOUNT) &&
  	    ((fdq->d_bcount >> sdp->sd_fsb2bb_shift) == be64_to_cpu(qd->qd_qb.qb_value)))
  		fdq->d_fieldmask ^= FS_DQ_BCOUNT;

  	if (fdq->d_fieldmask == 0)
  		goto out_i;
  
  	offset = qd2offset(qd);

  	alloc_required = gfs2_write_alloc_required(ip, offset, sizeof(struct gfs2_quota));

  	if (gfs2_is_stuffed(ip))
  		alloc_required = 1;

  	if (alloc_required) {

  		gfs2_write_calc_reserv(ip, sizeof(struct gfs2_quota),
  				       &data_blocks, &ind_blocks);

  		blocks = 1 + data_blocks + ind_blocks;
  		error = gfs2_inplace_reserve(ip, blocks);

  		if (error)

  			goto out_i;

  		blocks += gfs2_rg_blocks(ip);

  	}

  	/* Some quotas span block boundaries and can update two blocks,
  	   adding an extra block to the transaction to handle such quotas */
  	error = gfs2_trans_begin(sdp, blocks + RES_DINODE + 2, 0);

  	if (error)
  		goto out_release;
  
  	/* Apply changes */
  	error = gfs2_adjust_quota(ip, offset, 0, qd, fdq);
  
  	gfs2_trans_end(sdp);
  out_release:

  	if (alloc_required)

  		gfs2_inplace_release(ip);

  out_i:
  	gfs2_glock_dq_uninit(&i_gh);
  out_q:
  	gfs2_glock_dq_uninit(&q_gh);
  out_put:
  	mutex_unlock(&ip->i_inode.i_mutex);
  	qd_put(qd);
  	return error;
  }

  const struct quotactl_ops gfs2_quotactl_ops = {
  	.quota_sync     = gfs2_quota_sync,

  	.get_xstate     = gfs2_quota_get_xstate,

  	.get_dqblk	= gfs2_get_dqblk,

  	.set_dqblk	= gfs2_set_dqblk,

  };