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

   * Copyright (C) 2004-2006 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.

   */
  
  /*

   * Implements Extendible Hashing as described in:
   *   "Extendible Hashing" by Fagin, et al in
   *     __ACM Trans. on Database Systems__, Sept 1979.
   *
   *
   * Here's the layout of dirents which is essentially the same as that of ext2
   * within a single block. The field de_name_len is the number of bytes
   * actually required for the name (no null terminator). The field de_rec_len
   * is the number of bytes allocated to the dirent. The offset of the next
   * dirent in the block is (dirent + dirent->de_rec_len). When a dirent is
   * deleted, the preceding dirent inherits its allocated space, ie
   * prev->de_rec_len += deleted->de_rec_len. Since the next dirent is obtained
   * by adding de_rec_len to the current dirent, this essentially causes the
   * deleted dirent to get jumped over when iterating through all the dirents.
   *
   * When deleting the first dirent in a block, there is no previous dirent so
   * the field de_ino is set to zero to designate it as deleted. When allocating
   * a dirent, gfs2_dirent_alloc iterates through the dirents in a block. If the
   * first dirent has (de_ino == 0) and de_rec_len is large enough, this first
   * dirent is allocated. Otherwise it must go through all the 'used' dirents
   * searching for one in which the amount of total space minus the amount of
   * used space will provide enough space for the new dirent.
   *
   * There are two types of blocks in which dirents reside. In a stuffed dinode,
   * the dirents begin at offset sizeof(struct gfs2_dinode) from the beginning of
   * the block.  In leaves, they begin at offset sizeof(struct gfs2_leaf) from the
   * beginning of the leaf block. The dirents reside in leaves when
   *

   * dip->i_diskflags & GFS2_DIF_EXHASH is true

   *
   * Otherwise, the dirents are "linear", within a single stuffed dinode block.
   *
   * When the dirents are in leaves, the actual contents of the directory file are
   * used as an array of 64-bit block pointers pointing to the leaf blocks. The
   * dirents are NOT in the directory file itself. There can be more than one
   * block pointer in the array that points to the same leaf. In fact, when a
   * directory is first converted from linear to exhash, all of the pointers
   * point to the same leaf.
   *
   * When a leaf is completely full, the size of the hash table can be
   * doubled unless it is already at the maximum size which is hard coded into
   * GFS2_DIR_MAX_DEPTH. After that, leaves are chained together in a linked list,
   * but never before the maximum hash table size has been reached.
   */

  #include <linux/slab.h>
  #include <linux/spinlock.h>

  #include <linux/buffer_head.h>
  #include <linux/sort.h>

  #include <linux/gfs2_ondisk.h>

  #include <linux/crc32.h>

  #include <linux/vmalloc.h>

  
  #include "gfs2.h"

  #include "incore.h"

  #include "dir.h"
  #include "glock.h"
  #include "inode.h"

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

  #include "bmap.h"

  #include "util.h"

  
  #define IS_LEAF     1 /* Hashed (leaf) directory */
  #define IS_DINODE   2 /* Linear (stuffed dinode block) directory */

  #define MAX_RA_BLOCKS 32 /* max read-ahead blocks */

  #define gfs2_disk_hash2offset(h) (((u64)(h)) >> 1)
  #define gfs2_dir_offset2hash(p) ((u32)(((u64)(p)) << 1))

  struct qstr gfs2_qdot __read_mostly;
  struct qstr gfs2_qdotdot __read_mostly;

  typedef int (*gfs2_dscan_t)(const struct gfs2_dirent *dent,
  			    const struct qstr *name, void *opaque);

  int gfs2_dir_get_new_buffer(struct gfs2_inode *ip, u64 block,

  			    struct buffer_head **bhp)

  {
  	struct buffer_head *bh;

  	bh = gfs2_meta_new(ip->i_gl, block);
  	gfs2_trans_add_bh(ip->i_gl, bh, 1);
  	gfs2_metatype_set(bh, GFS2_METATYPE_JD, GFS2_FORMAT_JD);
  	gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));

  	*bhp = bh;
  	return 0;
  }

  static int gfs2_dir_get_existing_buffer(struct gfs2_inode *ip, u64 block,

  					struct buffer_head **bhp)
  {
  	struct buffer_head *bh;
  	int error;

  	error = gfs2_meta_read(ip->i_gl, block, DIO_WAIT, &bh);

  	if (error)
  		return error;

  	if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh, GFS2_METATYPE_JD)) {

  		brelse(bh);
  		return -EIO;
  	}
  	*bhp = bh;
  	return 0;
  }

  
  static int gfs2_dir_write_stuffed(struct gfs2_inode *ip, const char *buf,
  				  unsigned int offset, unsigned int size)

  {
  	struct buffer_head *dibh;
  	int error;
  
  	error = gfs2_meta_inode_buffer(ip, &dibh);
  	if (error)
  		return error;
  
  	gfs2_trans_add_bh(ip->i_gl, dibh, 1);

  	memcpy(dibh->b_data + offset + sizeof(struct gfs2_dinode), buf, size);

  	if (ip->i_inode.i_size < offset + size)
  		i_size_write(&ip->i_inode, offset + size);

  	ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;

  	gfs2_dinode_out(ip, dibh->b_data);

  
  	brelse(dibh);
  
  	return size;
  }
  
  
  
  /**
   * gfs2_dir_write_data - Write directory information to the inode
   * @ip: The GFS2 inode
   * @buf: The buffer containing information to be written
   * @offset: The file offset to start writing at
   * @size: The amount of data to write
   *
   * Returns: The number of bytes correctly written or error code
   */
  static int gfs2_dir_write_data(struct gfs2_inode *ip, const char *buf,

  			       u64 offset, unsigned int size)

  {

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

  	struct buffer_head *dibh;

  	u64 lblock, dblock;
  	u32 extlen = 0;

  	unsigned int o;
  	int copied = 0;
  	int error = 0;

  	int new = 0;

  
  	if (!size)
  		return 0;
  
  	if (gfs2_is_stuffed(ip) &&
  	    offset + size <= sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode))

  		return gfs2_dir_write_stuffed(ip, buf, (unsigned int)offset,
  					      size);

  
  	if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip)))
  		return -EINVAL;
  
  	if (gfs2_is_stuffed(ip)) {

  		error = gfs2_unstuff_dinode(ip, NULL);

  		if (error)

  			return error;

  	}
  
  	lblock = offset;
  	o = do_div(lblock, sdp->sd_jbsize) + sizeof(struct gfs2_meta_header);
  
  	while (copied < size) {
  		unsigned int amount;
  		struct buffer_head *bh;

  
  		amount = size - copied;
  		if (amount > sdp->sd_sb.sb_bsize - o)
  			amount = sdp->sd_sb.sb_bsize - o;
  
  		if (!extlen) {
  			new = 1;

  			error = gfs2_extent_map(&ip->i_inode, lblock, &new,

  						&dblock, &extlen);

  			if (error)
  				goto fail;
  			error = -EIO;
  			if (gfs2_assert_withdraw(sdp, dblock))
  				goto fail;
  		}

  		if (amount == sdp->sd_jbsize || new)
  			error = gfs2_dir_get_new_buffer(ip, dblock, &bh);
  		else
  			error = gfs2_dir_get_existing_buffer(ip, dblock, &bh);

  		if (error)
  			goto fail;
  
  		gfs2_trans_add_bh(ip->i_gl, bh, 1);
  		memcpy(bh->b_data + o, buf, amount);
  		brelse(bh);

  		buf += amount;

  		copied += amount;
  		lblock++;
  		dblock++;
  		extlen--;
  
  		o = sizeof(struct gfs2_meta_header);
  	}
  
  out:
  	error = gfs2_meta_inode_buffer(ip, &dibh);
  	if (error)
  		return error;

  	if (ip->i_inode.i_size < offset + copied)
  		i_size_write(&ip->i_inode, offset + copied);

  	ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;

  
  	gfs2_trans_add_bh(ip->i_gl, dibh, 1);

  	gfs2_dinode_out(ip, dibh->b_data);

  	brelse(dibh);
  
  	return copied;
  fail:
  	if (copied)
  		goto out;
  	return error;
  }

  static int gfs2_dir_read_stuffed(struct gfs2_inode *ip, __be64 *buf,
  				 unsigned int size)

  {
  	struct buffer_head *dibh;
  	int error;
  
  	error = gfs2_meta_inode_buffer(ip, &dibh);
  	if (!error) {

  		memcpy(buf, dibh->b_data + sizeof(struct gfs2_dinode), size);

  		brelse(dibh);
  	}
  
  	return (error) ? error : size;
  }
  
  
  /**
   * gfs2_dir_read_data - Read a data from a directory inode
   * @ip: The GFS2 Inode
   * @buf: The buffer to place result into

   * @size: Amount of data to transfer
   *
   * Returns: The amount of data actually copied or the error
   */

  static int gfs2_dir_read_data(struct gfs2_inode *ip, __be64 *buf,
  			      unsigned int size)

  {

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

  	u64 lblock, dblock;
  	u32 extlen = 0;

  	unsigned int o;
  	int copied = 0;
  	int error = 0;

  
  	if (gfs2_is_stuffed(ip))

  		return gfs2_dir_read_stuffed(ip, buf, size);

  
  	if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip)))
  		return -EINVAL;

  	lblock = 0;

  	o = do_div(lblock, sdp->sd_jbsize) + sizeof(struct gfs2_meta_header);
  
  	while (copied < size) {
  		unsigned int amount;
  		struct buffer_head *bh;
  		int new;
  
  		amount = size - copied;
  		if (amount > sdp->sd_sb.sb_bsize - o)
  			amount = sdp->sd_sb.sb_bsize - o;
  
  		if (!extlen) {
  			new = 0;

  			error = gfs2_extent_map(&ip->i_inode, lblock, &new,

  						&dblock, &extlen);

  			if (error || !dblock)

  				goto fail;

  			BUG_ON(extlen < 1);

  			bh = gfs2_meta_ra(ip->i_gl, dblock, extlen);

  		} else {

  			error = gfs2_meta_read(ip->i_gl, dblock, DIO_WAIT, &bh);

  			if (error)
  				goto fail;

  		}
  		error = gfs2_metatype_check(sdp, bh, GFS2_METATYPE_JD);
  		if (error) {
  			brelse(bh);
  			goto fail;
  		}
  		dblock++;
  		extlen--;

  		memcpy(buf, bh->b_data + o, amount);
  		brelse(bh);

  		buf += (amount/sizeof(__be64));

  		copied += amount;
  		lblock++;

  		o = sizeof(struct gfs2_meta_header);
  	}
  
  	return copied;
  fail:
  	return (copied) ? copied : error;
  }

  /**
   * gfs2_dir_get_hash_table - Get pointer to the dir hash table
   * @ip: The inode in question
   *
   * Returns: The hash table or an error
   */
  
  static __be64 *gfs2_dir_get_hash_table(struct gfs2_inode *ip)
  {
  	struct inode *inode = &ip->i_inode;
  	int ret;
  	u32 hsize;
  	__be64 *hc;
  
  	BUG_ON(!(ip->i_diskflags & GFS2_DIF_EXHASH));
  
  	hc = ip->i_hash_cache;
  	if (hc)
  		return hc;
  
  	hsize = 1 << ip->i_depth;
  	hsize *= sizeof(__be64);
  	if (hsize != i_size_read(&ip->i_inode)) {
  		gfs2_consist_inode(ip);
  		return ERR_PTR(-EIO);
  	}
  
  	hc = kmalloc(hsize, GFP_NOFS);
  	ret = -ENOMEM;
  	if (hc == NULL)
  		return ERR_PTR(-ENOMEM);

  	ret = gfs2_dir_read_data(ip, hc, hsize);

  	if (ret < 0) {
  		kfree(hc);
  		return ERR_PTR(ret);
  	}
  
  	spin_lock(&inode->i_lock);
  	if (ip->i_hash_cache)
  		kfree(hc);
  	else
  		ip->i_hash_cache = hc;
  	spin_unlock(&inode->i_lock);
  
  	return ip->i_hash_cache;
  }
  
  /**
   * gfs2_dir_hash_inval - Invalidate dir hash
   * @ip: The directory inode
   *
   * Must be called with an exclusive glock, or during glock invalidation.
   */
  void gfs2_dir_hash_inval(struct gfs2_inode *ip)
  {
  	__be64 *hc = ip->i_hash_cache;
  	ip->i_hash_cache = NULL;
  	kfree(hc);
  }

  static inline int gfs2_dirent_sentinel(const struct gfs2_dirent *dent)
  {
  	return dent->de_inum.no_addr == 0 || dent->de_inum.no_formal_ino == 0;
  }

  static inline int __gfs2_dirent_find(const struct gfs2_dirent *dent,
  				     const struct qstr *name, int ret)
  {

  	if (!gfs2_dirent_sentinel(dent) &&

  	    be32_to_cpu(dent->de_hash) == name->hash &&
  	    be16_to_cpu(dent->de_name_len) == name->len &&

  	    memcmp(dent+1, name->name, name->len) == 0)

  		return ret;
  	return 0;
  }
  
  static int gfs2_dirent_find(const struct gfs2_dirent *dent,

  			    const struct qstr *name,
  			    void *opaque)

  {
  	return __gfs2_dirent_find(dent, name, 1);
  }
  
  static int gfs2_dirent_prev(const struct gfs2_dirent *dent,

  			    const struct qstr *name,
  			    void *opaque)

  {
  	return __gfs2_dirent_find(dent, name, 2);
  }
  
  /*
   * name->name holds ptr to start of block.
   * name->len holds size of block.

   */

  static int gfs2_dirent_last(const struct gfs2_dirent *dent,

  			    const struct qstr *name,
  			    void *opaque)

  {
  	const char *start = name->name;
  	const char *end = (const char *)dent + be16_to_cpu(dent->de_rec_len);
  	if (name->len == (end - start))
  		return 1;
  	return 0;
  }

  static int gfs2_dirent_find_space(const struct gfs2_dirent *dent,

  				  const struct qstr *name,
  				  void *opaque)

  {

  	unsigned required = GFS2_DIRENT_SIZE(name->len);
  	unsigned actual = GFS2_DIRENT_SIZE(be16_to_cpu(dent->de_name_len));
  	unsigned totlen = be16_to_cpu(dent->de_rec_len);

  	if (gfs2_dirent_sentinel(dent))

  		actual = 0;

  	if (totlen - actual >= required)

  		return 1;
  	return 0;
  }

  struct dirent_gather {
  	const struct gfs2_dirent **pdent;
  	unsigned offset;
  };
  
  static int gfs2_dirent_gather(const struct gfs2_dirent *dent,
  			      const struct qstr *name,
  			      void *opaque)
  {
  	struct dirent_gather *g = opaque;

  	if (!gfs2_dirent_sentinel(dent)) {

  		g->pdent[g->offset++] = dent;
  	}
  	return 0;
  }

  /*
   * Other possible things to check:
   * - Inode located within filesystem size (and on valid block)
   * - Valid directory entry type
   * Not sure how heavy-weight we want to make this... could also check
   * hash is correct for example, but that would take a lot of extra time.
   * For now the most important thing is to check that the various sizes
   * are correct.
   */
  static int gfs2_check_dirent(struct gfs2_dirent *dent, unsigned int offset,
  			     unsigned int size, unsigned int len, int first)
  {
  	const char *msg = "gfs2_dirent too small";
  	if (unlikely(size < sizeof(struct gfs2_dirent)))
  		goto error;
  	msg = "gfs2_dirent misaligned";
  	if (unlikely(offset & 0x7))
  		goto error;
  	msg = "gfs2_dirent points beyond end of block";
  	if (unlikely(offset + size > len))
  		goto error;
  	msg = "zero inode number";

  	if (unlikely(!first && gfs2_dirent_sentinel(dent)))

  		goto error;
  	msg = "name length is greater than space in dirent";

  	if (!gfs2_dirent_sentinel(dent) &&

  	    unlikely(sizeof(struct gfs2_dirent)+be16_to_cpu(dent->de_name_len) >
  		     size))
  		goto error;
  	return 0;
  error:
  	printk(KERN_WARNING "gfs2_check_dirent: %s (%s)
  ", msg,
  	       first ? "first in block" : "not first in block");
  	return -EIO;

  }

  static int gfs2_dirent_offset(const void *buf)

  {

  	const struct gfs2_meta_header *h = buf;
  	int offset;

  
  	BUG_ON(buf == NULL);

  	switch(be32_to_cpu(h->mh_type)) {

  	case GFS2_METATYPE_LF:
  		offset = sizeof(struct gfs2_leaf);
  		break;
  	case GFS2_METATYPE_DI:
  		offset = sizeof(struct gfs2_dinode);
  		break;
  	default:
  		goto wrong_type;
  	}

  	return offset;
  wrong_type:
  	printk(KERN_WARNING "gfs2_scan_dirent: wrong block type %u
  ",

  	       be32_to_cpu(h->mh_type));

  	return -1;
  }

  static struct gfs2_dirent *gfs2_dirent_scan(struct inode *inode, void *buf,

  					    unsigned int len, gfs2_dscan_t scan,
  					    const struct qstr *name,
  					    void *opaque)
  {
  	struct gfs2_dirent *dent, *prev;
  	unsigned offset;
  	unsigned size;
  	int ret = 0;

  	ret = gfs2_dirent_offset(buf);
  	if (ret < 0)
  		goto consist_inode;
  
  	offset = ret;

  	prev = NULL;

  	dent = buf + offset;

  	size = be16_to_cpu(dent->de_rec_len);
  	if (gfs2_check_dirent(dent, offset, size, len, 1))
  		goto consist_inode;
  	do {

  		ret = scan(dent, name, opaque);

  		if (ret)
  			break;
  		offset += size;
  		if (offset == len)
  			break;
  		prev = dent;

  		dent = buf + offset;

  		size = be16_to_cpu(dent->de_rec_len);
  		if (gfs2_check_dirent(dent, offset, size, len, 0))
  			goto consist_inode;
  	} while(1);
  
  	switch(ret) {
  	case 0:
  		return NULL;
  	case 1:
  		return dent;
  	case 2:
  		return prev ? prev : dent;
  	default:
  		BUG_ON(ret > 0);
  		return ERR_PTR(ret);
  	}

  consist_inode:

  	gfs2_consist_inode(GFS2_I(inode));

  	return ERR_PTR(-EIO);
  }

  static int dirent_check_reclen(struct gfs2_inode *dip,
  			       const struct gfs2_dirent *d, const void *end_p)
  {
  	const void *ptr = d;
  	u16 rec_len = be16_to_cpu(d->de_rec_len);
  
  	if (unlikely(rec_len < sizeof(struct gfs2_dirent)))
  		goto broken;
  	ptr += rec_len;
  	if (ptr < end_p)
  		return rec_len;
  	if (ptr == end_p)
  		return -ENOENT;
  broken:
  	gfs2_consist_inode(dip);
  	return -EIO;
  }

  /**
   * dirent_next - Next dirent
   * @dip: the directory
   * @bh: The buffer
   * @dent: Pointer to list of dirents
   *
   * Returns: 0 on success, error code otherwise
   */
  
  static int dirent_next(struct gfs2_inode *dip, struct buffer_head *bh,
  		       struct gfs2_dirent **dent)
  {

  	struct gfs2_dirent *cur = *dent, *tmp;
  	char *bh_end = bh->b_data + bh->b_size;
  	int ret;

  	ret = dirent_check_reclen(dip, cur, bh_end);
  	if (ret < 0)
  		return ret;

  	tmp = (void *)cur + ret;
  	ret = dirent_check_reclen(dip, tmp, bh_end);
  	if (ret == -EIO)
  		return ret;

          /* Only the first dent could ever have de_inum.no_addr == 0 */

  	if (gfs2_dirent_sentinel(tmp)) {

  		gfs2_consist_inode(dip);
  		return -EIO;
  	}
  
  	*dent = tmp;

  	return 0;
  }
  
  /**
   * dirent_del - Delete a dirent
   * @dip: The GFS2 inode
   * @bh: The buffer
   * @prev: The previous dirent
   * @cur: The current dirent
   *
   */
  
  static void dirent_del(struct gfs2_inode *dip, struct buffer_head *bh,
  		       struct gfs2_dirent *prev, struct gfs2_dirent *cur)
  {

  	u16 cur_rec_len, prev_rec_len;

  	if (gfs2_dirent_sentinel(cur)) {

  		gfs2_consist_inode(dip);
  		return;
  	}

  	gfs2_trans_add_bh(dip->i_gl, bh, 1);

  
  	/* If there is no prev entry, this is the first entry in the block.
  	   The de_rec_len is already as big as it needs to be.  Just zero
  	   out the inode number and return.  */
  
  	if (!prev) {

  		cur->de_inum.no_addr = 0;
  		cur->de_inum.no_formal_ino = 0;

  		return;
  	}
  
  	/*  Combine this dentry with the previous one.  */

  	prev_rec_len = be16_to_cpu(prev->de_rec_len);
  	cur_rec_len = be16_to_cpu(cur->de_rec_len);

  
  	if ((char *)prev + prev_rec_len != (char *)cur)
  		gfs2_consist_inode(dip);
  	if ((char *)cur + cur_rec_len > bh->b_data + bh->b_size)
  		gfs2_consist_inode(dip);
  
  	prev_rec_len += cur_rec_len;

  	prev->de_rec_len = cpu_to_be16(prev_rec_len);

  }

  /*
   * Takes a dent from which to grab space as an argument. Returns the
   * newly created dent.

   */

  static struct gfs2_dirent *gfs2_init_dirent(struct inode *inode,
  					    struct gfs2_dirent *dent,
  					    const struct qstr *name,
  					    struct buffer_head *bh)

  {

  	struct gfs2_inode *ip = GFS2_I(inode);

  	struct gfs2_dirent *ndent;
  	unsigned offset = 0, totlen;

  	if (!gfs2_dirent_sentinel(dent))

  		offset = GFS2_DIRENT_SIZE(be16_to_cpu(dent->de_name_len));
  	totlen = be16_to_cpu(dent->de_rec_len);
  	BUG_ON(offset + name->len > totlen);
  	gfs2_trans_add_bh(ip->i_gl, bh, 1);
  	ndent = (struct gfs2_dirent *)((char *)dent + offset);
  	dent->de_rec_len = cpu_to_be16(offset);
  	gfs2_qstr2dirent(name, totlen - offset, ndent);
  	return ndent;

  }

  static struct gfs2_dirent *gfs2_dirent_alloc(struct inode *inode,
  					     struct buffer_head *bh,
  					     const struct qstr *name)

  {
  	struct gfs2_dirent *dent;

  	dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,

  				gfs2_dirent_find_space, name, NULL);

  	if (!dent || IS_ERR(dent))
  		return dent;
  	return gfs2_init_dirent(inode, dent, name, bh);

  }

  static int get_leaf(struct gfs2_inode *dip, u64 leaf_no,

  		    struct buffer_head **bhp)
  {
  	int error;

  	error = gfs2_meta_read(dip->i_gl, leaf_no, DIO_WAIT, bhp);

  	if (!error && gfs2_metatype_check(GFS2_SB(&dip->i_inode), *bhp, GFS2_METATYPE_LF)) {
  		/* printk(KERN_INFO "block num=%llu
  ", leaf_no); */

  		error = -EIO;

  	}

  
  	return error;
  }
  
  /**
   * get_leaf_nr - Get a leaf number associated with the index
   * @dip: The GFS2 inode
   * @index:
   * @leaf_out:
   *
   * Returns: 0 on success, error code otherwise
   */

  static int get_leaf_nr(struct gfs2_inode *dip, u32 index,
  		       u64 *leaf_out)

  {

  	__be64 *hash;

  	hash = gfs2_dir_get_hash_table(dip);
  	if (IS_ERR(hash))
  		return PTR_ERR(hash);
  	*leaf_out = be64_to_cpu(*(hash + index));

  	return 0;
  }

  static int get_first_leaf(struct gfs2_inode *dip, u32 index,

  			  struct buffer_head **bh_out)
  {

  	u64 leaf_no;

  	int error;
  
  	error = get_leaf_nr(dip, index, &leaf_no);
  	if (!error)
  		error = get_leaf(dip, leaf_no, bh_out);
  
  	return error;
  }

  static struct gfs2_dirent *gfs2_dirent_search(struct inode *inode,
  					      const struct qstr *name,
  					      gfs2_dscan_t scan,
  					      struct buffer_head **pbh)

  {

  	struct buffer_head *bh;
  	struct gfs2_dirent *dent;

  	struct gfs2_inode *ip = GFS2_I(inode);

  	int error;

  	if (ip->i_diskflags & GFS2_DIF_EXHASH) {

  		struct gfs2_leaf *leaf;

  		unsigned hsize = 1 << ip->i_depth;

  		unsigned index;
  		u64 ln;

  		if (hsize * sizeof(u64) != i_size_read(inode)) {

  			gfs2_consist_inode(ip);
  			return ERR_PTR(-EIO);
  		}

  		index = name->hash >> (32 - ip->i_depth);

  		error = get_first_leaf(ip, index, &bh);
  		if (error)
  			return ERR_PTR(error);
  		do {
  			dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,

  						scan, name, NULL);

  			if (dent)
  				goto got_dent;
  			leaf = (struct gfs2_leaf *)bh->b_data;
  			ln = be64_to_cpu(leaf->lf_next);

  			brelse(bh);

  			if (!ln)
  				break;

  			error = get_leaf(ip, ln, &bh);
  		} while(!error);

  		return error ? ERR_PTR(error) : NULL;

  	}

  	error = gfs2_meta_inode_buffer(ip, &bh);
  	if (error)
  		return ERR_PTR(error);

  	dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size, scan, name, NULL);

  got_dent:

  	if (unlikely(dent == NULL || IS_ERR(dent))) {

  		brelse(bh);
  		bh = NULL;
  	}

  	*pbh = bh;
  	return dent;
  }

  static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh, u16 depth)
  {

  	struct gfs2_inode *ip = GFS2_I(inode);

  	unsigned int n = 1;

  	u64 bn;
  	int error;
  	struct buffer_head *bh;

  	struct gfs2_leaf *leaf;
  	struct gfs2_dirent *dent;

  	struct qstr name = { .name = "", .len = 0, .hash = 0 };

  	error = gfs2_alloc_blocks(ip, &bn, &n, 0, NULL);

  	if (error)
  		return NULL;
  	bh = gfs2_meta_new(ip->i_gl, bn);

  	if (!bh)
  		return NULL;

  	gfs2_trans_add_unrevoke(GFS2_SB(inode), bn, 1);

  	gfs2_trans_add_bh(ip->i_gl, bh, 1);
  	gfs2_metatype_set(bh, GFS2_METATYPE_LF, GFS2_FORMAT_LF);
  	leaf = (struct gfs2_leaf *)bh->b_data;
  	leaf->lf_depth = cpu_to_be16(depth);

  	leaf->lf_entries = 0;

  	leaf->lf_dirent_format = cpu_to_be32(GFS2_FORMAT_DE);

  	leaf->lf_next = 0;

  	memset(leaf->lf_reserved, 0, sizeof(leaf->lf_reserved));
  	dent = (struct gfs2_dirent *)(leaf+1);

  	gfs2_qstr2dirent(&name, bh->b_size - sizeof(struct gfs2_leaf), dent);

  	*pbh = bh;
  	return leaf;

  }
  
  /**
   * dir_make_exhash - Convert a stuffed directory into an ExHash directory
   * @dip: The GFS2 inode
   *
   * Returns: 0 on success, error code otherwise
   */

  static int dir_make_exhash(struct inode *inode)

  {

  	struct gfs2_inode *dip = GFS2_I(inode);
  	struct gfs2_sbd *sdp = GFS2_SB(inode);

  	struct gfs2_dirent *dent;

  	struct qstr args;

  	struct buffer_head *bh, *dibh;
  	struct gfs2_leaf *leaf;
  	int y;

  	u32 x;

  	__be64 *lp;
  	u64 bn;

  	int error;
  
  	error = gfs2_meta_inode_buffer(dip, &dibh);
  	if (error)
  		return error;

  	/*  Turn over a new leaf  */

  	leaf = new_leaf(inode, &bh, 0);
  	if (!leaf)
  		return -ENOSPC;
  	bn = bh->b_blocknr;

  	gfs2_assert(sdp, dip->i_entries < (1 << 16));
  	leaf->lf_entries = cpu_to_be16(dip->i_entries);

  
  	/*  Copy dirents  */
  
  	gfs2_buffer_copy_tail(bh, sizeof(struct gfs2_leaf), dibh,
  			     sizeof(struct gfs2_dinode));
  
  	/*  Find last entry  */
  
  	x = 0;

  	args.len = bh->b_size - sizeof(struct gfs2_dinode) +
  		   sizeof(struct gfs2_leaf);
  	args.name = bh->b_data;

  	dent = gfs2_dirent_scan(&dip->i_inode, bh->b_data, bh->b_size,

  				gfs2_dirent_last, &args, NULL);

  	if (!dent) {
  		brelse(bh);
  		brelse(dibh);
  		return -EIO;
  	}
  	if (IS_ERR(dent)) {
  		brelse(bh);
  		brelse(dibh);
  		return PTR_ERR(dent);

  	}

  
  	/*  Adjust the last dirent's record length
  	   (Remember that dent still points to the last entry.)  */

  	dent->de_rec_len = cpu_to_be16(be16_to_cpu(dent->de_rec_len) +

  		sizeof(struct gfs2_dinode) -

  		sizeof(struct gfs2_leaf));

  
  	brelse(bh);
  
  	/*  We're done with the new leaf block, now setup the new
  	    hash table.  */

  	gfs2_trans_add_bh(dip->i_gl, dibh, 1);

  	gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));

  	lp = (__be64 *)(dibh->b_data + sizeof(struct gfs2_dinode));

  
  	for (x = sdp->sd_hash_ptrs; x--; lp++)
  		*lp = cpu_to_be64(bn);

  	i_size_write(inode, sdp->sd_sb.sb_bsize / 2);

  	gfs2_add_inode_blocks(&dip->i_inode, 1);

  	dip->i_diskflags |= GFS2_DIF_EXHASH;

  
  	for (x = sdp->sd_hash_ptrs, y = -1; x; x >>= 1, y++) ;

  	dip->i_depth = y;

  	gfs2_dinode_out(dip, dibh->b_data);

  
  	brelse(dibh);
  
  	return 0;
  }
  
  /**
   * dir_split_leaf - Split a leaf block into two
   * @dip: The GFS2 inode
   * @index:
   * @leaf_no:
   *
   * Returns: 0 on success, error code on failure
   */

  static int dir_split_leaf(struct inode *inode, const struct qstr *name)

  {

  	struct gfs2_inode *dip = GFS2_I(inode);

  	struct buffer_head *nbh, *obh, *dibh;
  	struct gfs2_leaf *nleaf, *oleaf;

  	struct gfs2_dirent *dent = NULL, *prev = NULL, *next = NULL, *new;

  	u32 start, len, half_len, divider;

  	u64 bn, leaf_no;
  	__be64 *lp;

  	u32 index;

  	int x, moved = 0;
  	int error;

  	index = name->hash >> (32 - dip->i_depth);

  	error = get_leaf_nr(dip, index, &leaf_no);
  	if (error)
  		return error;

  
  	/*  Get the old leaf block  */

  	error = get_leaf(dip, leaf_no, &obh);
  	if (error)

  		return error;

  	oleaf = (struct gfs2_leaf *)obh->b_data;

  	if (dip->i_depth == be16_to_cpu(oleaf->lf_depth)) {

  		brelse(obh);
  		return 1; /* can't split */
  	}
  
  	gfs2_trans_add_bh(dip->i_gl, obh, 1);

  	nleaf = new_leaf(inode, &nbh, be16_to_cpu(oleaf->lf_depth) + 1);
  	if (!nleaf) {
  		brelse(obh);
  		return -ENOSPC;
  	}
  	bn = nbh->b_blocknr;

  	/*  Compute the start and len of leaf pointers in the hash table.  */

  	len = 1 << (dip->i_depth - be16_to_cpu(oleaf->lf_depth));

  	half_len = len >> 1;
  	if (!half_len) {

  		printk(KERN_WARNING "i_depth %u lf_depth %u index %u
  ", dip->i_depth, be16_to_cpu(oleaf->lf_depth), index);

  		gfs2_consist_inode(dip);
  		error = -EIO;
  		goto fail_brelse;
  	}
  
  	start = (index & ~(len - 1));
  
  	/* Change the pointers.
  	   Don't bother distinguishing stuffed from non-stuffed.
  	   This code is complicated enough already. */

  	lp = kmalloc(half_len * sizeof(__be64), GFP_NOFS);
  	if (!lp) {
  		error = -ENOMEM;
  		goto fail_brelse;
  	}

  	/*  Change the pointers  */

  	for (x = 0; x < half_len; x++)
  		lp[x] = cpu_to_be64(bn);

  	gfs2_dir_hash_inval(dip);

  	error = gfs2_dir_write_data(dip, (char *)lp, start * sizeof(u64),
  				    half_len * sizeof(u64));
  	if (error != half_len * sizeof(u64)) {

  		if (error >= 0)
  			error = -EIO;
  		goto fail_lpfree;
  	}
  
  	kfree(lp);
  
  	/*  Compute the divider  */

  	divider = (start + half_len) << (32 - dip->i_depth);

  
  	/*  Copy the entries  */

  	dent = (struct gfs2_dirent *)(obh->b_data + sizeof(struct gfs2_leaf));

  
  	do {
  		next = dent;
  		if (dirent_next(dip, obh, &next))
  			next = NULL;

  		if (!gfs2_dirent_sentinel(dent) &&

  		    be32_to_cpu(dent->de_hash) < divider) {

  			struct qstr str;
  			str.name = (char*)(dent+1);
  			str.len = be16_to_cpu(dent->de_name_len);
  			str.hash = be32_to_cpu(dent->de_hash);

  			new = gfs2_dirent_alloc(inode, nbh, &str);

  			if (IS_ERR(new)) {
  				error = PTR_ERR(new);
  				break;
  			}

  
  			new->de_inum = dent->de_inum; /* No endian worries */

  			new->de_type = dent->de_type; /* No endian worries */

  			be16_add_cpu(&nleaf->lf_entries, 1);

  
  			dirent_del(dip, obh, prev, dent);
  
  			if (!oleaf->lf_entries)
  				gfs2_consist_inode(dip);

  			be16_add_cpu(&oleaf->lf_entries, -1);

  
  			if (!prev)
  				prev = dent;
  
  			moved = 1;

  		} else {

  			prev = dent;

  		}

  		dent = next;

  	} while (dent);

  	oleaf->lf_depth = nleaf->lf_depth;

  
  	error = gfs2_meta_inode_buffer(dip, &dibh);

  	if (!gfs2_assert_withdraw(GFS2_SB(&dip->i_inode), !error)) {

  		gfs2_trans_add_bh(dip->i_gl, dibh, 1);

  		gfs2_add_inode_blocks(&dip->i_inode, 1);

  		gfs2_dinode_out(dip, dibh->b_data);

  		brelse(dibh);
  	}
  
  	brelse(obh);
  	brelse(nbh);
  
  	return error;

  fail_lpfree:

  	kfree(lp);

  fail_brelse:

  	brelse(obh);

  	brelse(nbh);
  	return error;
  }
  
  /**
   * dir_double_exhash - Double size of ExHash table
   * @dip: The GFS2 dinode
   *
   * Returns: 0 on success, error code on failure
   */
  
  static int dir_double_exhash(struct gfs2_inode *dip)
  {

  	struct buffer_head *dibh;

  	u32 hsize;

  	u32 hsize_bytes;
  	__be64 *hc;
  	__be64 *hc2, *h;

  	int x;
  	int error = 0;

  	hsize = 1 << dip->i_depth;

  	hsize_bytes = hsize * sizeof(__be64);

  	hc = gfs2_dir_get_hash_table(dip);
  	if (IS_ERR(hc))
  		return PTR_ERR(hc);

  	h = hc2 = kmalloc(hsize_bytes * 2, GFP_NOFS);
  	if (!hc2)

  		return -ENOMEM;

  	error = gfs2_meta_inode_buffer(dip, &dibh);
  	if (error)
  		goto out_kfree;

  	for (x = 0; x < hsize; x++) {
  		*h++ = *hc;
  		*h++ = *hc;
  		hc++;

  	}

  	error = gfs2_dir_write_data(dip, (char *)hc2, 0, hsize_bytes * 2);
  	if (error != (hsize_bytes * 2))
  		goto fail;

  	gfs2_dir_hash_inval(dip);
  	dip->i_hash_cache = hc2;
  	dip->i_depth++;
  	gfs2_dinode_out(dip, dibh->b_data);
  	brelse(dibh);
  	return 0;

  fail:

  	/* Replace original hash table & size */
  	gfs2_dir_write_data(dip, (char *)hc, 0, hsize_bytes);
  	i_size_write(&dip->i_inode, hsize_bytes);
  	gfs2_dinode_out(dip, dibh->b_data);
  	brelse(dibh);
  out_kfree:
  	kfree(hc2);

  	return error;
  }
  
  /**
   * compare_dents - compare directory entries by hash value
   * @a: first dent
   * @b: second dent
   *
   * When comparing the hash entries of @a to @b:
   *   gt: returns 1
   *   lt: returns -1
   *   eq: returns 0
   */
  
  static int compare_dents(const void *a, const void *b)
  {

  	const struct gfs2_dirent *dent_a, *dent_b;

  	u32 hash_a, hash_b;

  	int ret = 0;

  	dent_a = *(const struct gfs2_dirent **)a;

  	hash_a = be32_to_cpu(dent_a->de_hash);

  	dent_b = *(const struct gfs2_dirent **)b;

  	hash_b = be32_to_cpu(dent_b->de_hash);

  
  	if (hash_a > hash_b)
  		ret = 1;
  	else if (hash_a < hash_b)
  		ret = -1;
  	else {

  		unsigned int len_a = be16_to_cpu(dent_a->de_name_len);
  		unsigned int len_b = be16_to_cpu(dent_b->de_name_len);

  
  		if (len_a > len_b)
  			ret = 1;
  		else if (len_a < len_b)
  			ret = -1;
  		else

  			ret = memcmp(dent_a + 1, dent_b + 1, len_a);

  	}
  
  	return ret;
  }
  
  /**
   * do_filldir_main - read out directory entries
   * @dip: The GFS2 inode
   * @offset: The offset in the file to read from
   * @opaque: opaque data to pass to filldir
   * @filldir: The function to pass entries to
   * @darr: an array of struct gfs2_dirent pointers to read
   * @entries: the number of entries in darr
   * @copied: pointer to int that's non-zero if a entry has been copied out
   *
   * Jump through some hoops to make sure that if there are hash collsions,
   * they are read out at the beginning of a buffer.  We want to minimize
   * the possibility that they will fall into different readdir buffers or
   * that someone will want to seek to that location.
   *
   * Returns: errno, >0 on exception from filldir
   */

  static int do_filldir_main(struct gfs2_inode *dip, u64 *offset,

  			   void *opaque, filldir_t filldir,

  			   const struct gfs2_dirent **darr, u32 entries,

  			   int *copied)
  {

  	const struct gfs2_dirent *dent, *dent_next;

  	u64 off, off_next;

  	unsigned int x, y;
  	int run = 0;
  	int error = 0;
  
  	sort(darr, entries, sizeof(struct gfs2_dirent *), compare_dents, NULL);
  
  	dent_next = darr[0];
  	off_next = be32_to_cpu(dent_next->de_hash);
  	off_next = gfs2_disk_hash2offset(off_next);
  
  	for (x = 0, y = 1; x < entries; x++, y++) {
  		dent = dent_next;
  		off = off_next;
  
  		if (y < entries) {
  			dent_next = darr[y];
  			off_next = be32_to_cpu(dent_next->de_hash);
  			off_next = gfs2_disk_hash2offset(off_next);
  
  			if (off < *offset)
  				continue;
  			*offset = off;
  
  			if (off_next == off) {
  				if (*copied && !run)
  					return 1;
  				run = 1;
  			} else
  				run = 0;
  		} else {
  			if (off < *offset)
  				continue;
  			*offset = off;
  		}

  		error = filldir(opaque, (const char *)(dent + 1),

  				be16_to_cpu(dent->de_name_len),

  				off, be64_to_cpu(dent->de_inum.no_addr),

  				be16_to_cpu(dent->de_type));

  		if (error)
  			return 1;
  
  		*copied = 1;
  	}
  
  	/* Increment the *offset by one, so the next time we come into the
  	   do_filldir fxn, we get the next entry instead of the last one in the
  	   current leaf */
  
  	(*offset)++;
  
  	return 0;
  }

  static void *gfs2_alloc_sort_buffer(unsigned size)
  {
  	void *ptr = NULL;
  
  	if (size < KMALLOC_MAX_SIZE)
  		ptr = kmalloc(size, GFP_NOFS | __GFP_NOWARN);
  	if (!ptr)
  		ptr = __vmalloc(size, GFP_NOFS, PAGE_KERNEL);
  	return ptr;
  }
  
  static void gfs2_free_sort_buffer(void *ptr)
  {
  	if (is_vmalloc_addr(ptr))
  		vfree(ptr);
  	else
  		kfree(ptr);
  }

  static int gfs2_dir_read_leaf(struct inode *inode, u64 *offset, void *opaque,

  			      filldir_t filldir, int *copied, unsigned *depth,
  			      u64 leaf_no)

  {

  	struct gfs2_inode *ip = GFS2_I(inode);

  	struct gfs2_sbd *sdp = GFS2_SB(inode);

  	struct buffer_head *bh;
  	struct gfs2_leaf *lf;

  	unsigned entries = 0, entries2 = 0;

  	unsigned leaves = 0;
  	const struct gfs2_dirent **darr, *dent;
  	struct dirent_gather g;
  	struct buffer_head **larr;
  	int leaf = 0;
  	int error, i;
  	u64 lfn = leaf_no;

  	do {

  		error = get_leaf(ip, lfn, &bh);

  		if (error)

  			goto out;
  		lf = (struct gfs2_leaf *)bh->b_data;
  		if (leaves == 0)
  			*depth = be16_to_cpu(lf->lf_depth);
  		entries += be16_to_cpu(lf->lf_entries);
  		leaves++;
  		lfn = be64_to_cpu(lf->lf_next);
  		brelse(bh);
  	} while(lfn);

  
  	if (!entries)
  		return 0;

  	error = -ENOMEM;

  	/*
  	 * The extra 99 entries are not normally used, but are a buffer
  	 * zone in case the number of entries in the leaf is corrupt.
  	 * 99 is the maximum number of entries that can fit in a single
  	 * leaf block.
  	 */

  	larr = gfs2_alloc_sort_buffer((leaves + entries + 99) * sizeof(void *));

  	if (!larr)
  		goto out;
  	darr = (const struct gfs2_dirent **)(larr + leaves);
  	g.pdent = darr;
  	g.offset = 0;
  	lfn = leaf_no;

  	do {
  		error = get_leaf(ip, lfn, &bh);

  		if (error)

  			goto out_free;

  		lf = (struct gfs2_leaf *)bh->b_data;
  		lfn = be64_to_cpu(lf->lf_next);
  		if (lf->lf_entries) {

  			entries2 += be16_to_cpu(lf->lf_entries);

  			dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,
  						gfs2_dirent_gather, NULL, &g);
  			error = PTR_ERR(dent);

  			if (IS_ERR(dent))

  				goto out_free;

  			if (entries2 != g.offset) {

  				fs_warn(sdp, "Number of entries corrupt in dir "
  						"leaf %llu, entries2 (%u) != "
  						"g.offset (%u)
  ",
  					(unsigned long long)bh->b_blocknr,
  					entries2, g.offset);

  					
  				error = -EIO;

  				goto out_free;

  			}
  			error = 0;
  			larr[leaf++] = bh;

  		} else {

  			brelse(bh);

  		}

  	} while(lfn);

  	BUG_ON(entries2 != entries);

  	error = do_filldir_main(ip, offset, opaque, filldir, darr,

  				entries, copied);

  out_free:

  	for(i = 0; i < leaf; i++)
  		brelse(larr[i]);

  	gfs2_free_sort_buffer(larr);

  out:

  	return error;
  }

  /**
   * gfs2_dir_readahead - Issue read-ahead requests for leaf blocks.

   *
   * Note: we can't calculate each index like dir_e_read can because we don't
   * have the leaf, and therefore we don't have the depth, and therefore we
   * don't have the length. So we have to just read enough ahead to make up

   * for the loss of information.
   */

  static void gfs2_dir_readahead(struct inode *inode, unsigned hsize, u32 index,
  			       struct file_ra_state *f_ra)
  {
  	struct gfs2_inode *ip = GFS2_I(inode);
  	struct gfs2_glock *gl = ip->i_gl;
  	struct buffer_head *bh;
  	u64 blocknr = 0, last;
  	unsigned count;
  
  	/* First check if we've already read-ahead for the whole range. */

  	if (index + MAX_RA_BLOCKS < f_ra->start)

  		return;
  
  	f_ra->start = max((pgoff_t)index, f_ra->start);
  	for (count = 0; count < MAX_RA_BLOCKS; count++) {
  		if (f_ra->start >= hsize) /* if exceeded the hash table */
  			break;
  
  		last = blocknr;
  		blocknr = be64_to_cpu(ip->i_hash_cache[f_ra->start]);
  		f_ra->start++;
  		if (blocknr == last)
  			continue;
  
  		bh = gfs2_getbuf(gl, blocknr, 1);
  		if (trylock_buffer(bh)) {
  			if (buffer_uptodate(bh)) {
  				unlock_buffer(bh);
  				brelse(bh);
  				continue;
  			}
  			bh->b_end_io = end_buffer_read_sync;
  			submit_bh(READA | REQ_META, bh);
  			continue;
  		}
  		brelse(bh);
  	}
  }

  /**

   * dir_e_read - Reads the entries from a directory into a filldir buffer
   * @dip: dinode pointer
   * @offset: the hash of the last entry read shifted to the right once
   * @opaque: buffer for the filldir function to fill
   * @filldir: points to the filldir function to use

   *

   * Returns: errno

   */

  static int dir_e_read(struct inode *inode, u64 *offset, void *opaque,

  		      filldir_t filldir, struct file_ra_state *f_ra)

  {

  	struct gfs2_inode *dip = GFS2_I(inode);

  	u32 hsize, len = 0;

  	u32 hash, index;

  	__be64 *lp;

  	int copied = 0;
  	int error = 0;

  	unsigned depth = 0;

  	hsize = 1 << dip->i_depth;

  	hash = gfs2_dir_offset2hash(*offset);

  	index = hash >> (32 - dip->i_depth);

  	if (dip->i_hash_cache == NULL)

  		f_ra->start = 0;

  	lp = gfs2_dir_get_hash_table(dip);
  	if (IS_ERR(lp))
  		return PTR_ERR(lp);

  	gfs2_dir_readahead(inode, hsize, index, f_ra);

  	while (index < hsize) {

  		error = gfs2_dir_read_leaf(inode, offset, opaque, filldir,
  					   &copied, &depth,

  					   be64_to_cpu(lp[index]));

  		if (error)

  			break;

  		len = 1 << (dip->i_depth - depth);

  		index = (index & ~(len - 1)) + len;
  	}

  	if (error > 0)
  		error = 0;

  	return error;
  }

  int gfs2_dir_read(struct inode *inode, u64 *offset, void *opaque,

  		  filldir_t filldir, struct file_ra_state *f_ra)

  {

  	struct gfs2_inode *dip = GFS2_I(inode);

  	struct gfs2_sbd *sdp = GFS2_SB(inode);

  	struct dirent_gather g;
  	const struct gfs2_dirent **darr, *dent;

  	struct buffer_head *dibh;
  	int copied = 0;
  	int error;

  	if (!dip->i_entries)

  		return 0;

  	if (dip->i_diskflags & GFS2_DIF_EXHASH)

  		return dir_e_read(inode, offset, opaque, filldir, f_ra);

  	if (!gfs2_is_stuffed(dip)) {
  		gfs2_consist_inode(dip);
  		return -EIO;
  	}

  	error = gfs2_meta_inode_buffer(dip, &dibh);
  	if (error)
  		return error;

  	error = -ENOMEM;

  	/* 96 is max number of dirents which can be stuffed into an inode */

  	darr = kmalloc(96 * sizeof(struct gfs2_dirent *), GFP_NOFS);

  	if (darr) {
  		g.pdent = darr;
  		g.offset = 0;
  		dent = gfs2_dirent_scan(inode, dibh->b_data, dibh->b_size,
  					gfs2_dirent_gather, NULL, &g);
  		if (IS_ERR(dent)) {
  			error = PTR_ERR(dent);
  			goto out;
  		}

  		if (dip->i_entries != g.offset) {

  			fs_warn(sdp, "Number of entries corrupt in dir %llu, "

  				"ip->i_entries (%u) != g.offset (%u)
  ",

  				(unsigned long long)dip->i_no_addr,

  				dip->i_entries,

  				g.offset);
  			error = -EIO;
  			goto out;
  		}

  		error = do_filldir_main(dip, offset, opaque, filldir, darr,

  					dip->i_entries, &copied);

  out:
  		kfree(darr);
  	}

  	if (error > 0)
  		error = 0;
  
  	brelse(dibh);
  
  	return error;
  }

  /**
   * gfs2_dir_search - Search a directory
   * @dip: The GFS2 inode
   * @filename:
   * @inode:
   *
   * This routine searches a directory for a file or another directory.
   * Assumes a glock is held on dip.
   *
   * Returns: errno
   */

  struct inode *gfs2_dir_search(struct inode *dir, const struct qstr *name)

  {

  	struct buffer_head *bh;
  	struct gfs2_dirent *dent;

  	struct inode *inode;
  
  	dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
  	if (dent) {
  		if (IS_ERR(dent))

  			return ERR_CAST(dent);

  		inode = gfs2_inode_lookup(dir->i_sb, 
  				be16_to_cpu(dent->de_type),
  				be64_to_cpu(dent->de_inum.no_addr),

  				be64_to_cpu(dent->de_inum.no_formal_ino), 0);

  		brelse(bh);
  		return inode;
  	}
  	return ERR_PTR(-ENOENT);
  }
  
  int gfs2_dir_check(struct inode *dir, const struct qstr *name,
  		   const struct gfs2_inode *ip)
  {
  	struct buffer_head *bh;
  	struct gfs2_dirent *dent;
  	int ret = -ENOENT;

  
  	dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
  	if (dent) {
  		if (IS_ERR(dent))
  			return PTR_ERR(dent);

  		if (ip) {
  			if (be64_to_cpu(dent->de_inum.no_addr) != ip->i_no_addr)
  				goto out;
  			if (be64_to_cpu(dent->de_inum.no_formal_ino) !=
  			    ip->i_no_formal_ino)
  				goto out;
  			if (unlikely(IF2DT(ip->i_inode.i_mode) !=
  			    be16_to_cpu(dent->de_type))) {
  				gfs2_consist_inode(GFS2_I(dir));
  				ret = -EIO;
  				goto out;
  			}
  		}
  		ret = 0;
  out:

  		brelse(bh);

  	}

  	return ret;

  }
  
  static int dir_new_leaf(struct inode *inode, const struct qstr *name)
  {
  	struct buffer_head *bh, *obh;

  	struct gfs2_inode *ip = GFS2_I(inode);

  	struct gfs2_leaf *leaf, *oleaf;

  	int error;

  	u32 index;
  	u64 bn;

  	index = name->hash >> (32 - ip->i_depth);

  	error = get_first_leaf(ip, index, &obh);
  	if (error)
  		return error;
  	do {
  		oleaf = (struct gfs2_leaf *)obh->b_data;
  		bn = be64_to_cpu(oleaf->lf_next);
  		if (!bn)
  			break;
  		brelse(obh);
  		error = get_leaf(ip, bn, &obh);
  		if (error)
  			return error;
  	} while(1);

  	gfs2_trans_add_bh(ip->i_gl, obh, 1);
  
  	leaf = new_leaf(inode, &bh, be16_to_cpu(oleaf->lf_depth));
  	if (!leaf) {
  		brelse(obh);
  		return -ENOSPC;
  	}

  	oleaf->lf_next = cpu_to_be64(bh->b_blocknr);

  	brelse(bh);
  	brelse(obh);
  
  	error = gfs2_meta_inode_buffer(ip, &bh);
  	if (error)
  		return error;
  	gfs2_trans_add_bh(ip->i_gl, bh, 1);

  	gfs2_add_inode_blocks(&ip->i_inode, 1);

  	gfs2_dinode_out(ip, bh->b_data);

  	brelse(bh);
  	return 0;

  }
  
  /**
   * gfs2_dir_add - Add new filename into directory
   * @dip: The GFS2 inode
   * @filename: The new name
   * @inode: The inode number of the entry
   * @type: The type of the entry
   *
   * Returns: 0 on success, error code on failure
   */

  int gfs2_dir_add(struct inode *inode, const struct qstr *name,

  		 const struct gfs2_inode *nip)

  {

  	struct gfs2_inode *ip = GFS2_I(inode);

  	struct buffer_head *bh;
  	struct gfs2_dirent *dent;
  	struct gfs2_leaf *leaf;

  	int error;

  	while(1) {
  		dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space,
  					  &bh);
  		if (dent) {
  			if (IS_ERR(dent))
  				return PTR_ERR(dent);
  			dent = gfs2_init_dirent(inode, dent, name, bh);

  			gfs2_inum_out(nip, dent);

  			dent->de_type = cpu_to_be16(IF2DT(nip->i_inode.i_mode));

  			if (ip->i_diskflags & GFS2_DIF_EXHASH) {

  				leaf = (struct gfs2_leaf *)bh->b_data;

  				be16_add_cpu(&leaf->lf_entries, 1);

  			}
  			brelse(bh);
  			error = gfs2_meta_inode_buffer(ip, &bh);
  			if (error)
  				break;
  			gfs2_trans_add_bh(ip->i_gl, bh, 1);

  			ip->i_entries++;

  			ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;

  			if (S_ISDIR(nip->i_inode.i_mode))
  				inc_nlink(&ip->i_inode);

  			gfs2_dinode_out(ip, bh->b_data);

  			brelse(bh);
  			error = 0;
  			break;
  		}

  		if (!(ip->i_diskflags & GFS2_DIF_EXHASH)) {

  			error = dir_make_exhash(inode);
  			if (error)
  				break;
  			continue;
  		}
  		error = dir_split_leaf(inode, name);
  		if (error == 0)
  			continue;

  		if (error < 0)

  			break;

  		if (ip->i_depth < GFS2_DIR_MAX_DEPTH) {

  			error = dir_double_exhash(ip);
  			if (error)
  				break;
  			error = dir_split_leaf(inode, name);

  			if (error < 0)

  				break;

  			if (error == 0)
  				continue;

  		}
  		error = dir_new_leaf(inode, name);
  		if (!error)
  			continue;
  		error = -ENOSPC;
  		break;
  	}

  	return error;
  }

  /**
   * gfs2_dir_del - Delete a directory entry
   * @dip: The GFS2 inode
   * @filename: The filename
   *
   * Returns: 0 on success, error code on failure
   */

  int gfs2_dir_del(struct gfs2_inode *dip, const struct dentry *dentry)

  {

  	const struct qstr *name = &dentry->d_name;

  	struct gfs2_dirent *dent, *prev = NULL;
  	struct buffer_head *bh;

  	/* Returns _either_ the entry (if its first in block) or the
  	   previous entry otherwise */

  	dent = gfs2_dirent_search(&dip->i_inode, name, gfs2_dirent_prev, &bh);

  	if (!dent) {
  		gfs2_consist_inode(dip);
  		return -EIO;
  	}
  	if (IS_ERR(dent)) {
  		gfs2_consist_inode(dip);
  		return PTR_ERR(dent);
  	}
  	/* If not first in block, adjust pointers accordingly */

  	if (gfs2_dirent_find(dent, name, NULL) == 0) {

  		prev = dent;
  		dent = (struct gfs2_dirent *)((char *)dent + be16_to_cpu(prev->de_rec_len));
  	}
  
  	dirent_del(dip, bh, prev, dent);

  	if (dip->i_diskflags & GFS2_DIF_EXHASH) {

  		struct gfs2_leaf *leaf = (struct gfs2_leaf *)bh->b_data;
  		u16 entries = be16_to_cpu(leaf->lf_entries);
  		if (!entries)
  			gfs2_consist_inode(dip);
  		leaf->lf_entries = cpu_to_be16(--entries);

  	}

  	brelse(bh);

  	if (!dip->i_entries)

  		gfs2_consist_inode(dip);

  	dip->i_entries--;

  	dip->i_inode.i_mtime = dip->i_inode.i_ctime = CURRENT_TIME;

  	if (S_ISDIR(dentry->d_inode->i_mode))
  		drop_nlink(&dip->i_inode);

  	mark_inode_dirty(&dip->i_inode);

  	return 0;

  }

  /**
   * gfs2_dir_mvino - Change inode number of directory entry
   * @dip: The GFS2 inode
   * @filename:
   * @new_inode:
   *
   * This routine changes the inode number of a directory entry.  It's used
   * by rename to change ".." when a directory is moved.
   * Assumes a glock is held on dvp.
   *
   * Returns: errno
   */

  int gfs2_dir_mvino(struct gfs2_inode *dip, const struct qstr *filename,

  		   const struct gfs2_inode *nip, unsigned int new_type)

  {

  	struct buffer_head *bh;
  	struct gfs2_dirent *dent;

  	int error;

  	dent = gfs2_dirent_search(&dip->i_inode, filename, gfs2_dirent_find, &bh);

  	if (!dent) {
  		gfs2_consist_inode(dip);
  		return -EIO;
  	}
  	if (IS_ERR(dent))
  		return PTR_ERR(dent);

  	gfs2_trans_add_bh(dip->i_gl, bh, 1);

  	gfs2_inum_out(nip, dent);

  	dent->de_type = cpu_to_be16(new_type);

  	if (dip->i_diskflags & GFS2_DIF_EXHASH) {

  		brelse(bh);
  		error = gfs2_meta_inode_buffer(dip, &bh);
  		if (error)
  			return error;
  		gfs2_trans_add_bh(dip->i_gl, bh, 1);
  	}

  	dip->i_inode.i_mtime = dip->i_inode.i_ctime = CURRENT_TIME;

  	gfs2_dinode_out(dip, bh->b_data);

  	brelse(bh);
  	return 0;

  }
  
  /**

   * leaf_dealloc - Deallocate a directory leaf
   * @dip: the directory
   * @index: the hash table offset in the directory
   * @len: the number of pointers to this leaf
   * @leaf_no: the leaf number

   * @leaf_bh: buffer_head for the starting leaf

   * last_dealloc: 1 if this is the final dealloc for the leaf, else 0

   *
   * Returns: errno
   */

  static int leaf_dealloc(struct gfs2_inode *dip, u32 index, u32 len,

  			u64 leaf_no, struct buffer_head *leaf_bh,
  			int last_dealloc)

  {

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

  	struct gfs2_leaf *tmp_leaf;

  	struct gfs2_rgrp_list rlist;
  	struct buffer_head *bh, *dibh;

  	u64 blk, nblk;

  	unsigned int rg_blocks = 0, l_blocks = 0;
  	char *ht;

  	unsigned int x, size = len * sizeof(u64);

  	int error;
  
  	memset(&rlist, 0, sizeof(struct gfs2_rgrp_list));

  	ht = kzalloc(size, GFP_NOFS);

  	if (!ht)
  		return -ENOMEM;

  	if (!gfs2_qadata_get(dip)) {

  		error = -ENOMEM;
  		goto out;
  	}

  
  	error = gfs2_quota_hold(dip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
  	if (error)

  		goto out_put;

  	/*  Count the number of leaves  */

  	bh = leaf_bh;

  	for (blk = leaf_no; blk; blk = nblk) {