/*
   *  Implementation of operations over global quota file
   */

  #include <linux/spinlock.h>

  #include <linux/fs.h>

  #include <linux/slab.h>

  #include <linux/quota.h>
  #include <linux/quotaops.h>
  #include <linux/dqblk_qtree.h>

  #include <linux/jiffies.h>
  #include <linux/writeback.h>
  #include <linux/workqueue.h>

  #include <linux/llist.h>

  #include <cluster/masklog.h>
  
  #include "ocfs2_fs.h"
  #include "ocfs2.h"
  #include "alloc.h"

  #include "blockcheck.h"

  #include "inode.h"
  #include "journal.h"
  #include "file.h"
  #include "sysfile.h"
  #include "dlmglue.h"
  #include "uptodate.h"

  #include "super.h"

  #include "buffer_head_io.h"

  #include "quota.h"

  #include "ocfs2_trace.h"

  /*
   * Locking of quotas with OCFS2 is rather complex. Here are rules that
   * should be obeyed by all the functions:
   * - any write of quota structure (either to local or global file) is protected
   *   by dqio_mutex or dquot->dq_lock.
   * - any modification of global quota file holds inode cluster lock, i_mutex,
   *   and ip_alloc_sem of the global quota file (achieved by
   *   ocfs2_lock_global_qf). It also has to hold qinfo_lock.
   * - an allocation of new blocks for local quota file is protected by
   *   its ip_alloc_sem
   *
   * A rough sketch of locking dependencies (lf = local file, gf = global file):
   * Normal filesystem operation:
   *   start_trans -> dqio_mutex -> write to lf
   * Syncing of local and global file:
   *   ocfs2_lock_global_qf -> start_trans -> dqio_mutex -> qinfo_lock ->
   *     write to gf
   *						       -> write to lf
   * Acquire dquot for the first time:
   *   dq_lock -> ocfs2_lock_global_qf -> qinfo_lock -> read from gf
   *				     -> alloc space for gf
   *				     -> start_trans -> qinfo_lock -> write to gf
   *	     -> ip_alloc_sem of lf -> alloc space for lf
   *	     -> write to lf
   * Release last reference to dquot:
   *   dq_lock -> ocfs2_lock_global_qf -> start_trans -> qinfo_lock -> write to gf
   *	     -> write to lf
   * Note that all the above operations also hold the inode cluster lock of lf.
   * Recovery:
   *   inode cluster lock of recovered lf
   *     -> read bitmaps -> ip_alloc_sem of lf
   *     -> ocfs2_lock_global_qf -> start_trans -> dqio_mutex -> qinfo_lock ->
   *        write to gf
   */

  static void qsync_work_fn(struct work_struct *work);

  static void ocfs2_global_disk2memdqb(struct dquot *dquot, void *dp)
  {
  	struct ocfs2_global_disk_dqblk *d = dp;
  	struct mem_dqblk *m = &dquot->dq_dqb;
  
  	/* Update from disk only entries not set by the admin */
  	if (!test_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags)) {
  		m->dqb_ihardlimit = le64_to_cpu(d->dqb_ihardlimit);
  		m->dqb_isoftlimit = le64_to_cpu(d->dqb_isoftlimit);
  	}
  	if (!test_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags))
  		m->dqb_curinodes = le64_to_cpu(d->dqb_curinodes);
  	if (!test_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags)) {
  		m->dqb_bhardlimit = le64_to_cpu(d->dqb_bhardlimit);
  		m->dqb_bsoftlimit = le64_to_cpu(d->dqb_bsoftlimit);
  	}
  	if (!test_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags))
  		m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
  	if (!test_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags))
  		m->dqb_btime = le64_to_cpu(d->dqb_btime);
  	if (!test_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags))
  		m->dqb_itime = le64_to_cpu(d->dqb_itime);
  	OCFS2_DQUOT(dquot)->dq_use_count = le32_to_cpu(d->dqb_use_count);
  }
  
  static void ocfs2_global_mem2diskdqb(void *dp, struct dquot *dquot)
  {
  	struct ocfs2_global_disk_dqblk *d = dp;
  	struct mem_dqblk *m = &dquot->dq_dqb;

  	d->dqb_id = cpu_to_le32(from_kqid(&init_user_ns, dquot->dq_id));

  	d->dqb_use_count = cpu_to_le32(OCFS2_DQUOT(dquot)->dq_use_count);
  	d->dqb_ihardlimit = cpu_to_le64(m->dqb_ihardlimit);
  	d->dqb_isoftlimit = cpu_to_le64(m->dqb_isoftlimit);
  	d->dqb_curinodes = cpu_to_le64(m->dqb_curinodes);
  	d->dqb_bhardlimit = cpu_to_le64(m->dqb_bhardlimit);
  	d->dqb_bsoftlimit = cpu_to_le64(m->dqb_bsoftlimit);
  	d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
  	d->dqb_btime = cpu_to_le64(m->dqb_btime);
  	d->dqb_itime = cpu_to_le64(m->dqb_itime);

  	d->dqb_pad1 = d->dqb_pad2 = 0;

  }
  
  static int ocfs2_global_is_id(void *dp, struct dquot *dquot)
  {
  	struct ocfs2_global_disk_dqblk *d = dp;
  	struct ocfs2_mem_dqinfo *oinfo =

  			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;

  
  	if (qtree_entry_unused(&oinfo->dqi_gi, dp))
  		return 0;

  
  	return qid_eq(make_kqid(&init_user_ns, dquot->dq_id.type,
  				le32_to_cpu(d->dqb_id)),
  		      dquot->dq_id);

  }
  
  struct qtree_fmt_operations ocfs2_global_ops = {
  	.mem2disk_dqblk = ocfs2_global_mem2diskdqb,
  	.disk2mem_dqblk = ocfs2_global_disk2memdqb,
  	.is_id = ocfs2_global_is_id,
  };

  int ocfs2_validate_quota_block(struct super_block *sb, struct buffer_head *bh)

  {

  	struct ocfs2_disk_dqtrailer *dqt =
  		ocfs2_block_dqtrailer(sb->s_blocksize, bh->b_data);

  	trace_ocfs2_validate_quota_block((unsigned long long)bh->b_blocknr);

  	BUG_ON(!buffer_uptodate(bh));
  
  	/*
  	 * If the ecc fails, we return the error but otherwise
  	 * leave the filesystem running.  We know any error is
  	 * local to this block.
  	 */
  	return ocfs2_validate_meta_ecc(sb, bh->b_data, &dqt->dq_check);

  }

  int ocfs2_read_quota_phys_block(struct inode *inode, u64 p_block,
  				struct buffer_head **bhp)
  {
  	int rc;
  
  	*bhp = NULL;
  	rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, 1, bhp, 0,
  			       ocfs2_validate_quota_block);
  	if (rc)
  		mlog_errno(rc);
  	return rc;
  }

  /* Read data from global quotafile - avoid pagecache and such because we cannot
   * afford acquiring the locks... We use quota cluster lock to serialize
   * operations. Caller is responsible for acquiring it. */
  ssize_t ocfs2_quota_read(struct super_block *sb, int type, char *data,
  			 size_t len, loff_t off)
  {
  	struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
  	struct inode *gqinode = oinfo->dqi_gqinode;
  	loff_t i_size = i_size_read(gqinode);
  	int offset = off & (sb->s_blocksize - 1);
  	sector_t blk = off >> sb->s_blocksize_bits;
  	int err = 0;
  	struct buffer_head *bh;
  	size_t toread, tocopy;

  	u64 pblock = 0, pcount = 0;

  
  	if (off > i_size)
  		return 0;
  	if (off + len > i_size)
  		len = i_size - off;
  	toread = len;
  	while (toread > 0) {

  		tocopy = min_t(size_t, (sb->s_blocksize - offset), toread);

  		if (!pcount) {
  			err = ocfs2_extent_map_get_blocks(gqinode, blk, &pblock,
  							  &pcount, NULL);
  			if (err) {
  				mlog_errno(err);
  				return err;
  			}
  		} else {
  			pcount--;
  			pblock++;
  		}

  		bh = NULL;

  		err = ocfs2_read_quota_phys_block(gqinode, pblock, &bh);

  		if (err) {

  			mlog_errno(err);
  			return err;
  		}
  		memcpy(data, bh->b_data + offset, tocopy);
  		brelse(bh);
  		offset = 0;
  		toread -= tocopy;
  		data += tocopy;
  		blk++;
  	}
  	return len;
  }
  
  /* Write to quotafile (we know the transaction is already started and has
   * enough credits) */
  ssize_t ocfs2_quota_write(struct super_block *sb, int type,
  			  const char *data, size_t len, loff_t off)
  {
  	struct mem_dqinfo *info = sb_dqinfo(sb, type);
  	struct ocfs2_mem_dqinfo *oinfo = info->dqi_priv;
  	struct inode *gqinode = oinfo->dqi_gqinode;
  	int offset = off & (sb->s_blocksize - 1);
  	sector_t blk = off >> sb->s_blocksize_bits;

  	int err = 0, new = 0, ja_type;

  	struct buffer_head *bh = NULL;

  	handle_t *handle = journal_current_handle();

  	u64 pblock, pcount;

  
  	if (!handle) {
  		mlog(ML_ERROR, "Quota write (off=%llu, len=%llu) cancelled "
  		     "because transaction was not started.
  ",
  		     (unsigned long long)off, (unsigned long long)len);
  		return -EIO;
  	}
  	if (len > sb->s_blocksize - OCFS2_QBLK_RESERVED_SPACE - offset) {
  		WARN_ON(1);
  		len = sb->s_blocksize - OCFS2_QBLK_RESERVED_SPACE - offset;
  	}

  	if (i_size_read(gqinode) < off + len) {

  		loff_t rounded_end =
  				ocfs2_align_bytes_to_blocks(sb, off + len);

  		/* Space is already allocated in ocfs2_acquire_dquot() */

  		err = ocfs2_simple_size_update(gqinode,
  					       oinfo->dqi_gqi_bh,

  					       rounded_end);

  		if (err < 0)
  			goto out;
  		new = 1;
  	}

  	err = ocfs2_extent_map_get_blocks(gqinode, blk, &pblock, &pcount, NULL);
  	if (err) {
  		mlog_errno(err);
  		goto out;
  	}

  	/* Not rewriting whole block? */
  	if ((offset || len < sb->s_blocksize - OCFS2_QBLK_RESERVED_SPACE) &&
  	    !new) {

  		err = ocfs2_read_quota_phys_block(gqinode, pblock, &bh);

  		ja_type = OCFS2_JOURNAL_ACCESS_WRITE;

  	} else {

  		bh = sb_getblk(sb, pblock);
  		if (!bh)
  			err = -ENOMEM;

  		ja_type = OCFS2_JOURNAL_ACCESS_CREATE;

  	}

  	if (err) {
  		mlog_errno(err);

  		goto out;

  	}
  	lock_buffer(bh);
  	if (new)
  		memset(bh->b_data, 0, sb->s_blocksize);
  	memcpy(bh->b_data + offset, data, len);
  	flush_dcache_page(bh->b_page);

  	set_buffer_uptodate(bh);

  	unlock_buffer(bh);

  	ocfs2_set_buffer_uptodate(INODE_CACHE(gqinode), bh);

  	err = ocfs2_journal_access_dq(handle, INODE_CACHE(gqinode), bh,
  				      ja_type);

  	if (err < 0) {
  		brelse(bh);
  		goto out;
  	}

  	ocfs2_journal_dirty(handle, bh);

  	brelse(bh);

  out:
  	if (err) {

  		mlog_errno(err);
  		return err;
  	}
  	gqinode->i_version++;
  	ocfs2_mark_inode_dirty(handle, gqinode, oinfo->dqi_gqi_bh);

  	return len;
  }
  
  int ocfs2_lock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex)
  {
  	int status;
  	struct buffer_head *bh = NULL;
  
  	status = ocfs2_inode_lock(oinfo->dqi_gqinode, &bh, ex);
  	if (status < 0)
  		return status;
  	spin_lock(&dq_data_lock);
  	if (!oinfo->dqi_gqi_count++)
  		oinfo->dqi_gqi_bh = bh;
  	else
  		WARN_ON(bh != oinfo->dqi_gqi_bh);
  	spin_unlock(&dq_data_lock);

  	if (ex) {
  		mutex_lock(&oinfo->dqi_gqinode->i_mutex);
  		down_write(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem);
  	} else {
  		down_read(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem);
  	}

  	return 0;
  }
  
  void ocfs2_unlock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex)
  {

  	if (ex) {
  		up_write(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem);
  		mutex_unlock(&oinfo->dqi_gqinode->i_mutex);
  	} else {
  		up_read(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem);
  	}

  	ocfs2_inode_unlock(oinfo->dqi_gqinode, ex);
  	brelse(oinfo->dqi_gqi_bh);
  	spin_lock(&dq_data_lock);
  	if (!--oinfo->dqi_gqi_count)
  		oinfo->dqi_gqi_bh = NULL;
  	spin_unlock(&dq_data_lock);
  }
  
  /* Read information header from global quota file */
  int ocfs2_global_read_info(struct super_block *sb, int type)
  {
  	struct inode *gqinode = NULL;

  	unsigned int ino[OCFS2_MAXQUOTAS] = { USER_QUOTA_SYSTEM_INODE,
  					      GROUP_QUOTA_SYSTEM_INODE };

  	struct ocfs2_global_disk_dqinfo dinfo;
  	struct mem_dqinfo *info = sb_dqinfo(sb, type);
  	struct ocfs2_mem_dqinfo *oinfo = info->dqi_priv;

  	u64 pcount;

  	int status;

  	/* Read global header */
  	gqinode = ocfs2_get_system_file_inode(OCFS2_SB(sb), ino[type],
  			OCFS2_INVALID_SLOT);
  	if (!gqinode) {
  		mlog(ML_ERROR, "failed to get global quota inode (type=%d)
  ",
  			type);
  		status = -EINVAL;
  		goto out_err;
  	}
  	oinfo->dqi_gi.dqi_sb = sb;
  	oinfo->dqi_gi.dqi_type = type;
  	ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
  	oinfo->dqi_gi.dqi_entry_size = sizeof(struct ocfs2_global_disk_dqblk);
  	oinfo->dqi_gi.dqi_ops = &ocfs2_global_ops;
  	oinfo->dqi_gqi_bh = NULL;
  	oinfo->dqi_gqi_count = 0;
  	oinfo->dqi_gqinode = gqinode;
  	status = ocfs2_lock_global_qf(oinfo, 0);
  	if (status < 0) {
  		mlog_errno(status);
  		goto out_err;
  	}

  
  	status = ocfs2_extent_map_get_blocks(gqinode, 0, &oinfo->dqi_giblk,
  					     &pcount, NULL);
  	if (status < 0)
  		goto out_unlock;
  
  	status = ocfs2_qinfo_lock(oinfo, 0);
  	if (status < 0)
  		goto out_unlock;

  	status = sb->s_op->quota_read(sb, type, (char *)&dinfo,
  				      sizeof(struct ocfs2_global_disk_dqinfo),
  				      OCFS2_GLOBAL_INFO_OFF);

  	ocfs2_qinfo_unlock(oinfo, 0);

  	ocfs2_unlock_global_qf(oinfo, 0);
  	if (status != sizeof(struct ocfs2_global_disk_dqinfo)) {
  		mlog(ML_ERROR, "Cannot read global quota info (%d).
  ",
  		     status);
  		if (status >= 0)
  			status = -EIO;
  		mlog_errno(status);
  		goto out_err;
  	}
  	info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
  	info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
  	oinfo->dqi_syncms = le32_to_cpu(dinfo.dqi_syncms);
  	oinfo->dqi_gi.dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
  	oinfo->dqi_gi.dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
  	oinfo->dqi_gi.dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
  	oinfo->dqi_gi.dqi_blocksize_bits = sb->s_blocksize_bits;
  	oinfo->dqi_gi.dqi_usable_bs = sb->s_blocksize -
  						OCFS2_QBLK_RESERVED_SPACE;
  	oinfo->dqi_gi.dqi_qtree_depth = qtree_depth(&oinfo->dqi_gi);

  	INIT_DELAYED_WORK(&oinfo->dqi_sync_work, qsync_work_fn);

  	schedule_delayed_work(&oinfo->dqi_sync_work,
  			      msecs_to_jiffies(oinfo->dqi_syncms));

  out_err:

  	return status;

  out_unlock:
  	ocfs2_unlock_global_qf(oinfo, 0);
  	mlog_errno(status);
  	goto out_err;

  }
  
  /* Write information to global quota file. Expects exlusive lock on quota
   * file inode and quota info */
  static int __ocfs2_global_write_info(struct super_block *sb, int type)
  {
  	struct mem_dqinfo *info = sb_dqinfo(sb, type);
  	struct ocfs2_mem_dqinfo *oinfo = info->dqi_priv;
  	struct ocfs2_global_disk_dqinfo dinfo;
  	ssize_t size;
  
  	spin_lock(&dq_data_lock);
  	info->dqi_flags &= ~DQF_INFO_DIRTY;
  	dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
  	dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
  	spin_unlock(&dq_data_lock);
  	dinfo.dqi_syncms = cpu_to_le32(oinfo->dqi_syncms);
  	dinfo.dqi_blocks = cpu_to_le32(oinfo->dqi_gi.dqi_blocks);
  	dinfo.dqi_free_blk = cpu_to_le32(oinfo->dqi_gi.dqi_free_blk);
  	dinfo.dqi_free_entry = cpu_to_le32(oinfo->dqi_gi.dqi_free_entry);
  	size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
  				     sizeof(struct ocfs2_global_disk_dqinfo),
  				     OCFS2_GLOBAL_INFO_OFF);
  	if (size != sizeof(struct ocfs2_global_disk_dqinfo)) {
  		mlog(ML_ERROR, "Cannot write global quota info structure
  ");
  		if (size >= 0)
  			size = -EIO;
  		return size;
  	}
  	return 0;
  }
  
  int ocfs2_global_write_info(struct super_block *sb, int type)
  {
  	int err;
  	struct ocfs2_mem_dqinfo *info = sb_dqinfo(sb, type)->dqi_priv;
  
  	err = ocfs2_qinfo_lock(info, 1);
  	if (err < 0)
  		return err;
  	err = __ocfs2_global_write_info(sb, type);
  	ocfs2_qinfo_unlock(info, 1);
  	return err;
  }

  static int ocfs2_global_qinit_alloc(struct super_block *sb, int type)
  {
  	struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
  
  	/*
  	 * We may need to allocate tree blocks and a leaf block but not the
  	 * root block
  	 */
  	return oinfo->dqi_gi.dqi_qtree_depth;
  }
  
  static int ocfs2_calc_global_qinit_credits(struct super_block *sb, int type)
  {

  	/* We modify all the allocated blocks, tree root, info block and
  	 * the inode */

  	return (ocfs2_global_qinit_alloc(sb, type) + 2) *

  			OCFS2_QUOTA_BLOCK_UPDATE_CREDITS + 1;

  }

  /* Sync local information about quota modifications with global quota file.
   * Caller must have started the transaction and obtained exclusive lock for
   * global quota file inode */
  int __ocfs2_sync_dquot(struct dquot *dquot, int freeing)
  {
  	int err, err2;
  	struct super_block *sb = dquot->dq_sb;

  	int type = dquot->dq_id.type;

  	struct ocfs2_mem_dqinfo *info = sb_dqinfo(sb, type)->dqi_priv;
  	struct ocfs2_global_disk_dqblk dqblk;
  	s64 spacechange, inodechange;
  	time_t olditime, oldbtime;
  
  	err = sb->s_op->quota_read(sb, type, (char *)&dqblk,
  				   sizeof(struct ocfs2_global_disk_dqblk),
  				   dquot->dq_off);
  	if (err != sizeof(struct ocfs2_global_disk_dqblk)) {
  		if (err >= 0) {
  			mlog(ML_ERROR, "Short read from global quota file "
  				       "(%u read)
  ", err);
  			err = -EIO;
  		}
  		goto out;
  	}
  
  	/* Update space and inode usage. Get also other information from
  	 * global quota file so that we don't overwrite any changes there.
  	 * We are */
  	spin_lock(&dq_data_lock);
  	spacechange = dquot->dq_dqb.dqb_curspace -
  					OCFS2_DQUOT(dquot)->dq_origspace;
  	inodechange = dquot->dq_dqb.dqb_curinodes -
  					OCFS2_DQUOT(dquot)->dq_originodes;
  	olditime = dquot->dq_dqb.dqb_itime;
  	oldbtime = dquot->dq_dqb.dqb_btime;
  	ocfs2_global_disk2memdqb(dquot, &dqblk);

  	trace_ocfs2_sync_dquot(from_kqid(&init_user_ns, dquot->dq_id),
  			       dquot->dq_dqb.dqb_curspace,

  			       (long long)spacechange,
  			       dquot->dq_dqb.dqb_curinodes,
  			       (long long)inodechange);

  	if (!test_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags))
  		dquot->dq_dqb.dqb_curspace += spacechange;
  	if (!test_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags))
  		dquot->dq_dqb.dqb_curinodes += inodechange;
  	/* Set properly space grace time... */
  	if (dquot->dq_dqb.dqb_bsoftlimit &&
  	    dquot->dq_dqb.dqb_curspace > dquot->dq_dqb.dqb_bsoftlimit) {
  		if (!test_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags) &&
  		    oldbtime > 0) {
  			if (dquot->dq_dqb.dqb_btime > 0)
  				dquot->dq_dqb.dqb_btime =
  					min(dquot->dq_dqb.dqb_btime, oldbtime);
  			else
  				dquot->dq_dqb.dqb_btime = oldbtime;
  		}
  	} else {
  		dquot->dq_dqb.dqb_btime = 0;
  		clear_bit(DQ_BLKS_B, &dquot->dq_flags);
  	}
  	/* Set properly inode grace time... */
  	if (dquot->dq_dqb.dqb_isoftlimit &&
  	    dquot->dq_dqb.dqb_curinodes > dquot->dq_dqb.dqb_isoftlimit) {
  		if (!test_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags) &&
  		    olditime > 0) {
  			if (dquot->dq_dqb.dqb_itime > 0)
  				dquot->dq_dqb.dqb_itime =
  					min(dquot->dq_dqb.dqb_itime, olditime);
  			else
  				dquot->dq_dqb.dqb_itime = olditime;
  		}
  	} else {
  		dquot->dq_dqb.dqb_itime = 0;
  		clear_bit(DQ_INODES_B, &dquot->dq_flags);
  	}
  	/* All information is properly updated, clear the flags */
  	__clear_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
  	__clear_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
  	__clear_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
  	__clear_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
  	__clear_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
  	__clear_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
  	OCFS2_DQUOT(dquot)->dq_origspace = dquot->dq_dqb.dqb_curspace;
  	OCFS2_DQUOT(dquot)->dq_originodes = dquot->dq_dqb.dqb_curinodes;
  	spin_unlock(&dq_data_lock);
  	err = ocfs2_qinfo_lock(info, freeing);
  	if (err < 0) {

  		mlog(ML_ERROR, "Failed to lock quota info, losing quota write"

  			       " (type=%d, id=%u)
  ", dquot->dq_id.type,
  			       (unsigned)from_kqid(&init_user_ns, dquot->dq_id));

  		goto out;
  	}
  	if (freeing)
  		OCFS2_DQUOT(dquot)->dq_use_count--;
  	err = qtree_write_dquot(&info->dqi_gi, dquot);
  	if (err < 0)
  		goto out_qlock;
  	if (freeing && !OCFS2_DQUOT(dquot)->dq_use_count) {
  		err = qtree_release_dquot(&info->dqi_gi, dquot);
  		if (info_dirty(sb_dqinfo(sb, type))) {
  			err2 = __ocfs2_global_write_info(sb, type);
  			if (!err)
  				err = err2;
  		}
  	}
  out_qlock:
  	ocfs2_qinfo_unlock(info, freeing);
  out:
  	if (err < 0)
  		mlog_errno(err);
  	return err;
  }
  
  /*

   *  Functions for periodic syncing of dquots with global file
   */
  static int ocfs2_sync_dquot_helper(struct dquot *dquot, unsigned long type)
  {
  	handle_t *handle;
  	struct super_block *sb = dquot->dq_sb;
  	struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
  	struct ocfs2_super *osb = OCFS2_SB(sb);
  	int status = 0;

  	trace_ocfs2_sync_dquot_helper(from_kqid(&init_user_ns, dquot->dq_id),
  				      dquot->dq_id.type,

  				      type, sb->s_id);

  	if (type != dquot->dq_id.type)

  		goto out;
  	status = ocfs2_lock_global_qf(oinfo, 1);
  	if (status < 0)
  		goto out;
  
  	handle = ocfs2_start_trans(osb, OCFS2_QSYNC_CREDITS);
  	if (IS_ERR(handle)) {
  		status = PTR_ERR(handle);
  		mlog_errno(status);
  		goto out_ilock;
  	}
  	mutex_lock(&sb_dqopt(sb)->dqio_mutex);
  	status = ocfs2_sync_dquot(dquot);

  	if (status < 0)
  		mlog_errno(status);
  	/* We have to write local structure as well... */

  	status = ocfs2_local_write_dquot(dquot);

  	if (status < 0)
  		mlog_errno(status);

  	mutex_unlock(&sb_dqopt(sb)->dqio_mutex);

  	ocfs2_commit_trans(osb, handle);
  out_ilock:
  	ocfs2_unlock_global_qf(oinfo, 1);
  out:

  	return status;
  }
  
  static void qsync_work_fn(struct work_struct *work)
  {
  	struct ocfs2_mem_dqinfo *oinfo = container_of(work,
  						      struct ocfs2_mem_dqinfo,
  						      dqi_sync_work.work);
  	struct super_block *sb = oinfo->dqi_gqinode->i_sb;
  
  	dquot_scan_active(sb, ocfs2_sync_dquot_helper, oinfo->dqi_type);

  	schedule_delayed_work(&oinfo->dqi_sync_work,
  			      msecs_to_jiffies(oinfo->dqi_syncms));

  }
  
  /*

   *  Wrappers for generic quota functions
   */
  
  static int ocfs2_write_dquot(struct dquot *dquot)
  {
  	handle_t *handle;
  	struct ocfs2_super *osb = OCFS2_SB(dquot->dq_sb);
  	int status = 0;

  	trace_ocfs2_write_dquot(from_kqid(&init_user_ns, dquot->dq_id),
  				dquot->dq_id.type);

  
  	handle = ocfs2_start_trans(osb, OCFS2_QWRITE_CREDITS);
  	if (IS_ERR(handle)) {
  		status = PTR_ERR(handle);
  		mlog_errno(status);
  		goto out;
  	}

  	mutex_lock(&sb_dqopt(dquot->dq_sb)->dqio_mutex);
  	status = ocfs2_local_write_dquot(dquot);
  	mutex_unlock(&sb_dqopt(dquot->dq_sb)->dqio_mutex);

  	ocfs2_commit_trans(osb, handle);
  out:

  	return status;
  }

  static int ocfs2_calc_qdel_credits(struct super_block *sb, int type)

  {

  	struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;

  	/*
  	 * We modify tree, leaf block, global info, local chunk header,
  	 * global and local inode; OCFS2_QINFO_WRITE_CREDITS already
  	 * accounts for inode update
  	 */

  	return (oinfo->dqi_gi.dqi_qtree_depth + 2) *
  	       OCFS2_QUOTA_BLOCK_UPDATE_CREDITS +

  	       OCFS2_QINFO_WRITE_CREDITS +

  	       OCFS2_INODE_UPDATE_CREDITS;

  }

  void ocfs2_drop_dquot_refs(struct work_struct *work)
  {
  	struct ocfs2_super *osb = container_of(work, struct ocfs2_super,
  					       dquot_drop_work);
  	struct llist_node *list;
  	struct ocfs2_dquot *odquot, *next_odquot;
  
  	list = llist_del_all(&osb->dquot_drop_list);
  	llist_for_each_entry_safe(odquot, next_odquot, list, list) {
  		/* Drop the reference we acquired in ocfs2_dquot_release() */
  		dqput(&odquot->dq_dquot);
  	}
  }
  
  /*
   * Called when the last reference to dquot is dropped. If we are called from
   * downconvert thread, we cannot do all the handling here because grabbing
   * quota lock could deadlock (the node holding the quota lock could need some
   * other cluster lock to proceed but with blocked downconvert thread we cannot
   * release any lock).
   */

  static int ocfs2_release_dquot(struct dquot *dquot)
  {
  	handle_t *handle;
  	struct ocfs2_mem_dqinfo *oinfo =

  			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;

  	struct ocfs2_super *osb = OCFS2_SB(dquot->dq_sb);
  	int status = 0;

  	trace_ocfs2_release_dquot(from_kqid(&init_user_ns, dquot->dq_id),
  				  dquot->dq_id.type);

  	mutex_lock(&dquot->dq_lock);
  	/* Check whether we are not racing with some other dqget() */
  	if (atomic_read(&dquot->dq_count) > 1)
  		goto out;

  	/* Running from downconvert thread? Postpone quota processing to wq */
  	if (current == osb->dc_task) {
  		/*
  		 * Grab our own reference to dquot and queue it for delayed
  		 * dropping.  Quota code rechecks after calling
  		 * ->release_dquot() and won't free dquot structure.
  		 */
  		dqgrab(dquot);
  		/* First entry on list -> queue work */
  		if (llist_add(&OCFS2_DQUOT(dquot)->list, &osb->dquot_drop_list))
  			queue_work(ocfs2_wq, &osb->dquot_drop_work);
  		goto out;
  	}

  	status = ocfs2_lock_global_qf(oinfo, 1);
  	if (status < 0)
  		goto out;
  	handle = ocfs2_start_trans(osb,

  		ocfs2_calc_qdel_credits(dquot->dq_sb, dquot->dq_id.type));

  	if (IS_ERR(handle)) {
  		status = PTR_ERR(handle);
  		mlog_errno(status);
  		goto out_ilock;
  	}

  
  	status = ocfs2_global_release_dquot(dquot);
  	if (status < 0) {
  		mlog_errno(status);
  		goto out_trans;
  	}
  	status = ocfs2_local_release_dquot(handle, dquot);
  	/*
  	 * If we fail here, we cannot do much as global structure is
  	 * already released. So just complain...
  	 */
  	if (status < 0)
  		mlog_errno(status);

  	/*
  	 * Clear dq_off so that we search for the structure in quota file next
  	 * time we acquire it. The structure might be deleted and reallocated
  	 * elsewhere by another node while our dquot structure is on freelist.
  	 */
  	dquot->dq_off = 0;

  	clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
  out_trans:

  	ocfs2_commit_trans(osb, handle);
  out_ilock:
  	ocfs2_unlock_global_qf(oinfo, 1);
  out:

  	mutex_unlock(&dquot->dq_lock);

  	if (status)
  		mlog_errno(status);

  	return status;
  }

  /*
   * Read global dquot structure from disk or create it if it does
   * not exist. Also update use count of the global structure and
   * create structure in node-local quota file.
   */

  static int ocfs2_acquire_dquot(struct dquot *dquot)
  {

  	int status = 0, err;
  	int ex = 0;
  	struct super_block *sb = dquot->dq_sb;
  	struct ocfs2_super *osb = OCFS2_SB(sb);

  	int type = dquot->dq_id.type;

  	struct ocfs2_mem_dqinfo *info = sb_dqinfo(sb, type)->dqi_priv;
  	struct inode *gqinode = info->dqi_gqinode;
  	int need_alloc = ocfs2_global_qinit_alloc(sb, type);
  	handle_t *handle;

  	trace_ocfs2_acquire_dquot(from_kqid(&init_user_ns, dquot->dq_id),
  				  type);

  	mutex_lock(&dquot->dq_lock);
  	/*
  	 * We need an exclusive lock, because we're going to update use count
  	 * and instantiate possibly new dquot structure
  	 */
  	status = ocfs2_lock_global_qf(info, 1);

  	if (status < 0)
  		goto out;

  	status = ocfs2_qinfo_lock(info, 0);
  	if (status < 0)
  		goto out_dq;
  	/*
  	 * We always want to read dquot structure from disk because we don't
  	 * know what happened with it while it was on freelist.
  	 */
  	status = qtree_read_dquot(&info->dqi_gi, dquot);
  	ocfs2_qinfo_unlock(info, 0);
  	if (status < 0)
  		goto out_dq;

  
  	OCFS2_DQUOT(dquot)->dq_use_count++;
  	OCFS2_DQUOT(dquot)->dq_origspace = dquot->dq_dqb.dqb_curspace;
  	OCFS2_DQUOT(dquot)->dq_originodes = dquot->dq_dqb.dqb_curinodes;
  	if (!dquot->dq_off) {	/* No real quota entry? */
  		ex = 1;
  		/*
  		 * Add blocks to quota file before we start a transaction since
  		 * locking allocators ranks above a transaction start
  		 */
  		WARN_ON(journal_current_handle());

  		status = ocfs2_extend_no_holes(gqinode, NULL,

  			i_size_read(gqinode) + (need_alloc << sb->s_blocksize_bits),
  			i_size_read(gqinode));

  		if (status < 0)
  			goto out_dq;
  	}
  
  	handle = ocfs2_start_trans(osb,
  				   ocfs2_calc_global_qinit_credits(sb, type));
  	if (IS_ERR(handle)) {
  		status = PTR_ERR(handle);
  		goto out_dq;
  	}
  	status = ocfs2_qinfo_lock(info, ex);
  	if (status < 0)
  		goto out_trans;
  	status = qtree_write_dquot(&info->dqi_gi, dquot);
  	if (ex && info_dirty(sb_dqinfo(sb, type))) {
  		err = __ocfs2_global_write_info(sb, type);
  		if (!status)
  			status = err;
  	}
  	ocfs2_qinfo_unlock(info, ex);
  out_trans:
  	ocfs2_commit_trans(osb, handle);
  out_dq:
  	ocfs2_unlock_global_qf(info, 1);
  	if (status < 0)
  		goto out;
  
  	status = ocfs2_create_local_dquot(dquot);
  	if (status < 0)
  		goto out;
  	set_bit(DQ_ACTIVE_B, &dquot->dq_flags);

  out:

  	mutex_unlock(&dquot->dq_lock);

  	if (status)
  		mlog_errno(status);

  	return status;
  }
  
  static int ocfs2_mark_dquot_dirty(struct dquot *dquot)
  {
  	unsigned long mask = (1 << (DQ_LASTSET_B + QIF_ILIMITS_B)) |
  			     (1 << (DQ_LASTSET_B + QIF_BLIMITS_B)) |
  			     (1 << (DQ_LASTSET_B + QIF_INODES_B)) |
  			     (1 << (DQ_LASTSET_B + QIF_SPACE_B)) |
  			     (1 << (DQ_LASTSET_B + QIF_BTIME_B)) |
  			     (1 << (DQ_LASTSET_B + QIF_ITIME_B));
  	int sync = 0;
  	int status;
  	struct super_block *sb = dquot->dq_sb;

  	int type = dquot->dq_id.type;

  	struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
  	handle_t *handle;
  	struct ocfs2_super *osb = OCFS2_SB(sb);

  	trace_ocfs2_mark_dquot_dirty(from_kqid(&init_user_ns, dquot->dq_id),
  				     type);

  
  	/* In case user set some limits, sync dquot immediately to global
  	 * quota file so that information propagates quicker */
  	spin_lock(&dq_data_lock);
  	if (dquot->dq_flags & mask)
  		sync = 1;
  	spin_unlock(&dq_data_lock);

  	/* This is a slight hack but we can't afford getting global quota
  	 * lock if we already have a transaction started. */
  	if (!sync || journal_current_handle()) {

  		status = ocfs2_write_dquot(dquot);
  		goto out;
  	}
  	status = ocfs2_lock_global_qf(oinfo, 1);
  	if (status < 0)
  		goto out;
  	handle = ocfs2_start_trans(osb, OCFS2_QSYNC_CREDITS);
  	if (IS_ERR(handle)) {
  		status = PTR_ERR(handle);
  		mlog_errno(status);
  		goto out_ilock;
  	}

  	mutex_lock(&sb_dqopt(sb)->dqio_mutex);

  	status = ocfs2_sync_dquot(dquot);
  	if (status < 0) {
  		mlog_errno(status);

  		goto out_dlock;

  	}
  	/* Now write updated local dquot structure */

  	status = ocfs2_local_write_dquot(dquot);
  out_dlock:
  	mutex_unlock(&sb_dqopt(sb)->dqio_mutex);

  	ocfs2_commit_trans(osb, handle);
  out_ilock:
  	ocfs2_unlock_global_qf(oinfo, 1);
  out:

  	if (status)
  		mlog_errno(status);

  	return status;
  }
  
  /* This should happen only after set_dqinfo(). */
  static int ocfs2_write_info(struct super_block *sb, int type)
  {
  	handle_t *handle;
  	int status = 0;
  	struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;

  	status = ocfs2_lock_global_qf(oinfo, 1);
  	if (status < 0)
  		goto out;
  	handle = ocfs2_start_trans(OCFS2_SB(sb), OCFS2_QINFO_WRITE_CREDITS);
  	if (IS_ERR(handle)) {
  		status = PTR_ERR(handle);
  		mlog_errno(status);
  		goto out_ilock;
  	}
  	status = dquot_commit_info(sb, type);
  	ocfs2_commit_trans(OCFS2_SB(sb), handle);
  out_ilock:
  	ocfs2_unlock_global_qf(oinfo, 1);
  out:

  	if (status)
  		mlog_errno(status);

  	return status;
  }

  static struct dquot *ocfs2_alloc_dquot(struct super_block *sb, int type)
  {
  	struct ocfs2_dquot *dquot =
  				kmem_cache_zalloc(ocfs2_dquot_cachep, GFP_NOFS);
  
  	if (!dquot)
  		return NULL;
  	return &dquot->dq_dquot;
  }
  
  static void ocfs2_destroy_dquot(struct dquot *dquot)
  {
  	kmem_cache_free(ocfs2_dquot_cachep, dquot);
  }

  const struct dquot_operations ocfs2_quota_operations = {

  	/* We never make dquot dirty so .write_dquot is never called */

  	.acquire_dquot	= ocfs2_acquire_dquot,
  	.release_dquot	= ocfs2_release_dquot,
  	.mark_dirty	= ocfs2_mark_dquot_dirty,
  	.write_info	= ocfs2_write_info,
  	.alloc_dquot	= ocfs2_alloc_dquot,
  	.destroy_dquot	= ocfs2_destroy_dquot,
  };