/*
   * 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_di.di_flags & 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/sched.h>
  #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 <linux/lm_interface.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 gfs2_disk_hash2offset(h) (((u64)(h)) >> 1)
  #define gfs2_dir_offset2hash(p) ((u32)(((u64)(p)) << 1))

  typedef int (*leaf_call_t) (struct gfs2_inode *dip, u32 index, u32 len,

  			    u64 leaf_no, void *data);
  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_di.di_size < offset + size)
  		ip->i_di.di_size = offset + size;
  	ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
  	gfs2_dinode_out(&ip->i_di, 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;
  
  	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;

  		int new = 0;

  
  		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_di.di_size < offset + copied)
  		ip->i_di.di_size = offset + copied;
  	ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
  
  	gfs2_trans_add_bh(ip->i_gl, dibh, 1);
  	gfs2_dinode_out(&ip->i_di, dibh->b_data);
  	brelse(dibh);
  
  	return copied;
  fail:
  	if (copied)
  		goto out;
  	return error;
  }
  
  static int gfs2_dir_read_stuffed(struct gfs2_inode *ip, char *buf,

  				 u64 offset, unsigned int size)

  {
  	struct buffer_head *dibh;
  	int error;
  
  	error = gfs2_meta_inode_buffer(ip, &dibh);
  	if (!error) {
  		offset += sizeof(struct gfs2_dinode);
  		memcpy(buf, dibh->b_data + offset, 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
   * @offset: File offset to begin jdata_readng from
   * @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, char *buf, u64 offset,
  			      unsigned int size, unsigned ra)

  {

  	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 (offset >= ip->i_di.di_size)
  		return 0;

  	if (offset + size > ip->i_di.di_size)

  		size = ip->i_di.di_size - offset;
  
  	if (!size)
  		return 0;
  
  	if (gfs2_is_stuffed(ip))

  		return gfs2_dir_read_stuffed(ip, buf, offset, size);

  
  	if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip)))
  		return -EINVAL;
  
  	lblock = offset;
  	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);
  			if (!ra)
  				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;

  		copied += amount;
  		lblock++;

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

  static inline int __gfs2_dirent_find(const struct gfs2_dirent *dent,
  				     const struct qstr *name, int ret)
  {
  	if (dent->de_inum.no_addr != 0 &&
  	    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 (!dent->de_inum.no_addr)
  		actual = GFS2_DIRENT_SIZE(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 (dent->de_inum.no_addr) {
  		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 && !dent->de_inum.no_addr))
  		goto error;
  	msg = "name length is greater than space in dirent";
  	if (dent->de_inum.no_addr &&
  	    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);
  }

  /**
   * dirent_first - Return the first dirent
   * @dip: the directory
   * @bh: The buffer
   * @dent: Pointer to list of dirents
   *
   * return first dirent whether bh points to leaf or stuffed dinode
   *
   * Returns: IS_LEAF, IS_DINODE, or -errno
   */
  
  static int dirent_first(struct gfs2_inode *dip, struct buffer_head *bh,
  			struct gfs2_dirent **dent)
  {
  	struct gfs2_meta_header *h = (struct gfs2_meta_header *)bh->b_data;

  	if (be32_to_cpu(h->mh_type) == GFS2_METATYPE_LF) {

  		if (gfs2_meta_check(GFS2_SB(&dip->i_inode), bh))

  			return -EIO;
  		*dent = (struct gfs2_dirent *)(bh->b_data +
  					       sizeof(struct gfs2_leaf));
  		return IS_LEAF;
  	} else {

  		if (gfs2_metatype_check(GFS2_SB(&dip->i_inode), bh, GFS2_METATYPE_DI))

  			return -EIO;
  		*dent = (struct gfs2_dirent *)(bh->b_data +
  					       sizeof(struct gfs2_dinode));
  		return IS_DINODE;
  	}
  }

  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 (!tmp->de_inum.no_addr) {
  		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 (!cur->de_inum.no_addr) {
  		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;	/* No endianess worries */
  		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 (dent->de_inum.no_addr)
  		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 leaf_no;

  	int error;

  	error = gfs2_dir_read_data(dip, (char *)&leaf_no,

  				    index * sizeof(__be64),
  				    sizeof(__be64), 0);

  	if (error != sizeof(u64))

  		return (error < 0) ? error : -EIO;
  
  	*leaf_out = be64_to_cpu(leaf_no);
  
  	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_di.di_flags & GFS2_DIF_EXHASH) {
  		struct gfs2_leaf *leaf;
  		unsigned hsize = 1 << ip->i_di.di_depth;
  		unsigned index;
  		u64 ln;
  		if (hsize * sizeof(u64) != ip->i_di.di_size) {
  			gfs2_consist_inode(ip);
  			return ERR_PTR(-EIO);
  		}

  		index = name->hash >> (32 - ip->i_di.di_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);

  	u64 bn = gfs2_alloc_meta(ip);
  	struct buffer_head *bh = gfs2_meta_new(ip->i_gl, bn);
  	struct gfs2_leaf *leaf;
  	struct gfs2_dirent *dent;

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

  	if (!bh)
  		return NULL;

  	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_di.di_entries < (1 << 16));

  	leaf->lf_entries = cpu_to_be16(dip->i_di.di_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);
  
  	dip->i_di.di_size = sdp->sd_sb.sb_bsize / 2;
  	dip->i_di.di_blocks++;
  	dip->i_di.di_flags |= GFS2_DIF_EXHASH;
  	dip->i_di.di_payload_format = 0;
  
  	for (x = sdp->sd_hash_ptrs, y = -1; x; x >>= 1, y++) ;
  	dip->i_di.di_depth = y;
  
  	gfs2_dinode_out(&dip->i_di, 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_di.di_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_di.di_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_di.di_depth - be16_to_cpu(oleaf->lf_depth));
  	half_len = len >> 1;
  	if (!half_len) {

  		printk(KERN_WARNING "di_depth %u lf_depth %u index %u
  ", dip->i_di.di_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 | __GFP_NOFAIL);

  	/*  Change the pointers  */

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

  	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_di.di_depth);
  
  	/*  Copy the entries  */

  	dirent_first(dip, obh, &dent);
  
  	do {
  		next = dent;
  		if (dirent_next(dip, obh, &next))
  			next = NULL;
  
  		if (dent->de_inum.no_addr &&
  		    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 */

  			nleaf->lf_entries = cpu_to_be16(be16_to_cpu(nleaf->lf_entries)+1);

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

  			oleaf->lf_entries = cpu_to_be16(be16_to_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)) {

  		dip->i_di.di_blocks++;
  		gfs2_dinode_out(&dip->i_di, 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 gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);

  	struct buffer_head *dibh;

  	u32 hsize;
  	u64 *buf;
  	u64 *from, *to;
  	u64 block;

  	int x;
  	int error = 0;
  
  	hsize = 1 << dip->i_di.di_depth;

  	if (hsize * sizeof(u64) != dip->i_di.di_size) {

  		gfs2_consist_inode(dip);
  		return -EIO;
  	}
  
  	/*  Allocate both the "from" and "to" buffers in one big chunk  */
  
  	buf = kcalloc(3, sdp->sd_hash_bsize, GFP_KERNEL | __GFP_NOFAIL);
  
  	for (block = dip->i_di.di_size >> sdp->sd_hash_bsize_shift; block--;) {

  		error = gfs2_dir_read_data(dip, (char *)buf,

  					    block * sdp->sd_hash_bsize,

  					    sdp->sd_hash_bsize, 1);

  		if (error != sdp->sd_hash_bsize) {
  			if (error >= 0)
  				error = -EIO;
  			goto fail;
  		}
  
  		from = buf;

  		to = (u64 *)((char *)buf + sdp->sd_hash_bsize);

  
  		for (x = sdp->sd_hash_ptrs; x--; from++) {
  			*to++ = *from;	/*  No endianess worries  */
  			*to++ = *from;
  		}

  		error = gfs2_dir_write_data(dip,

  					     (char *)buf + sdp->sd_hash_bsize,
  					     block * sdp->sd_sb.sb_bsize,
  					     sdp->sd_sb.sb_bsize);
  		if (error != sdp->sd_sb.sb_bsize) {
  			if (error >= 0)
  				error = -EIO;
  			goto fail;
  		}
  	}
  
  	kfree(buf);
  
  	error = gfs2_meta_inode_buffer(dip, &dibh);
  	if (!gfs2_assert_withdraw(sdp, !error)) {
  		dip->i_di.di_depth++;
  		gfs2_dinode_out(&dip->i_di, dibh->b_data);
  		brelse(dibh);
  	}
  
  	return error;

  fail:

  	kfree(buf);

  	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, gfs2_filldir_t filldir,

  			   const struct gfs2_dirent **darr, u32 entries,

  			   int *copied)
  {

  	const struct gfs2_dirent *dent, *dent_next;

  	struct gfs2_inum_host inum;

  	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;
  		}
  
  		gfs2_inum_in(&inum, (char *)&dent->de_inum);

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

  				be16_to_cpu(dent->de_name_len),

  				off, &inum,

  				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 int gfs2_dir_read_leaf(struct inode *inode, u64 *offset, void *opaque,
  			      gfs2_filldir_t filldir, int *copied,
  			      unsigned *depth, u64 leaf_no)

  {

  	struct gfs2_inode *ip = GFS2_I(inode);

  	struct buffer_head *bh;
  	struct gfs2_leaf *lf;
  	unsigned entries = 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;

  	larr = vmalloc((leaves + entries) * 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_kfree;
  		lf = (struct gfs2_leaf *)bh->b_data;
  		lfn = be64_to_cpu(lf->lf_next);
  		if (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_kfree;
  			}
  			error = 0;
  			larr[leaf++] = bh;

  		} else {

  			brelse(bh);

  		}

  	} while(lfn);

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

  				entries, copied);

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

  	vfree(larr);

  out:

  	return error;
  }
  
  /**

   * 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,

  		      gfs2_filldir_t filldir)

  {

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

  	u32 hsize, len = 0;
  	u32 ht_offset, lp_offset, ht_offset_cur = -1;
  	u32 hash, index;

  	__be64 *lp;

  	int copied = 0;
  	int error = 0;

  	unsigned depth = 0;

  
  	hsize = 1 << dip->i_di.di_depth;

  	if (hsize * sizeof(u64) != dip->i_di.di_size) {

  		gfs2_consist_inode(dip);
  		return -EIO;
  	}
  
  	hash = gfs2_dir_offset2hash(*offset);
  	index = hash >> (32 - dip->i_di.di_depth);
  
  	lp = kmalloc(sdp->sd_hash_bsize, GFP_KERNEL);
  	if (!lp)
  		return -ENOMEM;
  
  	while (index < hsize) {
  		lp_offset = index & (sdp->sd_hash_ptrs - 1);
  		ht_offset = index - lp_offset;
  
  		if (ht_offset_cur != ht_offset) {

  			error = gfs2_dir_read_data(dip, (char *)lp,

  						ht_offset * sizeof(__be64),

  						sdp->sd_hash_bsize, 1);

  			if (error != sdp->sd_hash_bsize) {
  				if (error >= 0)
  					error = -EIO;
  				goto out;
  			}
  			ht_offset_cur = ht_offset;
  		}

  		error = gfs2_dir_read_leaf(inode, offset, opaque, filldir,
  					   &copied, &depth,
  					   be64_to_cpu(lp[lp_offset]));

  		if (error)

  			break;

  		len = 1 << (dip->i_di.di_depth - depth);

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

  out:

  	kfree(lp);

  	if (error > 0)
  		error = 0;

  	return error;
  }

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

  		  gfs2_filldir_t filldir)

  {

  	struct gfs2_inode *dip = GFS2_I(inode);

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

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

  	if (!dip->i_di.di_entries)
  		return 0;
  
  	if (dip->i_di.di_flags & GFS2_DIF_EXHASH)
  		return dir_e_read(inode, offset, opaque, filldir);

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

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

  	error = -ENOMEM;
  	darr = kmalloc(dip->i_di.di_entries * sizeof(struct gfs2_dirent *),
  		       GFP_KERNEL);
  	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;
  		}
  		error = do_filldir_main(dip, offset, opaque, filldir, darr,
  					dip->i_di.di_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
   */

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

  		    struct gfs2_inum_host *inum, unsigned int *type)

  {

  	struct buffer_head *bh;
  	struct gfs2_dirent *dent;
  
  	dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
  	if (dent) {
  		if (IS_ERR(dent))
  			return PTR_ERR(dent);
  		if (inum)
  			gfs2_inum_in(inum, (char *)&dent->de_inum);
  		if (type)
  			*type = be16_to_cpu(dent->de_type);
  		brelse(bh);
  		return 0;
  	}
  	return -ENOENT;
  }
  
  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_di.di_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);
  	ip->i_di.di_blocks++;
  	gfs2_dinode_out(&ip->i_di, 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_inum_host *inum, unsigned type)

  {

  	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(inum, (char *)&dent->de_inum);
  			dent->de_type = cpu_to_be16(type);
  			if (ip->i_di.di_flags & GFS2_DIF_EXHASH) {
  				leaf = (struct gfs2_leaf *)bh->b_data;
  				leaf->lf_entries = cpu_to_be16(be16_to_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_di.di_entries++;
  			ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
  			gfs2_dinode_out(&ip->i_di, bh->b_data);
  			brelse(bh);
  			error = 0;
  			break;
  		}
  		if (!(ip->i_di.di_flags & 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_di.di_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 qstr *name)

  {

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

  	int error;

  	/* 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_di.di_flags & 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);

  
  	error = gfs2_meta_inode_buffer(dip, &bh);
  	if (error)
  		return error;
  
  	if (!dip->i_di.di_entries)
  		gfs2_consist_inode(dip);
  	gfs2_trans_add_bh(dip->i_gl, bh, 1);
  	dip->i_di.di_entries--;
  	dip->i_di.di_mtime = dip->i_di.di_ctime = get_seconds();
  	gfs2_dinode_out(&dip->i_di, bh->b_data);
  	brelse(bh);

  	mark_inode_dirty(&dip->i_inode);

  
  	return error;
  }

  /**
   * 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,

  		   struct gfs2_inum_host *inum, 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(inum, (char *)&dent->de_inum);
  	dent->de_type = cpu_to_be16(new_type);
  
  	if (dip->i_di.di_flags & 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_di.di_mtime = dip->i_di.di_ctime = get_seconds();
  	gfs2_dinode_out(&dip->i_di, bh->b_data);
  	brelse(bh);
  	return 0;

  }
  
  /**
   * foreach_leaf - call a function for each leaf in a directory
   * @dip: the directory
   * @lc: the function to call for each each
   * @data: private data to pass to it
   *
   * Returns: errno
   */
  
  static int foreach_leaf(struct gfs2_inode *dip, leaf_call_t lc, void *data)
  {

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

  	struct buffer_head *bh;

  	struct gfs2_leaf *leaf;

  	u32 hsize, len;
  	u32 ht_offset, lp_offset, ht_offset_cur = -1;
  	u32 index = 0;

  	__be64 *lp;

  	u64 leaf_no;

  	int error = 0;
  
  	hsize = 1 << dip->i_di.di_depth;

  	if (hsize * sizeof(u64) != dip->i_di.di_size) {

  		gfs2_consist_inode(dip);
  		return -EIO;
  	}
  
  	lp = kmalloc(sdp->sd_hash_bsize, GFP_KERNEL);
  	if (!lp)
  		return -ENOMEM;
  
  	while (index < hsize) {
  		lp_offset = index & (sdp->sd_hash_ptrs - 1);
  		ht_offset = index - lp_offset;
  
  		if (ht_offset_cur != ht_offset) {

  			error = gfs2_dir_read_data(dip, (char *)lp,

  						ht_offset * sizeof(__be64),

  						sdp->sd_hash_bsize, 1);

  			if (error != sdp->sd_hash_bsize) {
  				if (error >= 0)
  					error = -EIO;
  				goto out;
  			}
  			ht_offset_cur = ht_offset;
  		}
  
  		leaf_no = be64_to_cpu(lp[lp_offset]);
  		if (leaf_no) {
  			error = get_leaf(dip, leaf_no, &bh);
  			if (error)
  				goto out;

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

  			len = 1 << (dip->i_di.di_depth - be16_to_cpu(leaf->lf_depth));

  			brelse(bh);

  
  			error = lc(dip, index, len, leaf_no, data);
  			if (error)
  				goto out;
  
  			index = (index & ~(len - 1)) + len;
  		} else
  			index++;
  	}
  
  	if (index != hsize) {
  		gfs2_consist_inode(dip);
  		error = -EIO;
  	}

  out:

  	kfree(lp);
  
  	return error;
  }
  
  /**
   * 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
   * @data: not used
   *
   * Returns: errno
   */

  static int leaf_dealloc(struct gfs2_inode *dip, u32 index, u32 len,
  			u64 leaf_no, void *data)

  {

  	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_KERNEL);
  	if (!ht)
  		return -ENOMEM;
  
  	gfs2_alloc_get(dip);
  
  	error = gfs2_quota_hold(dip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
  	if (error)
  		goto out;
  
  	error = gfs2_rindex_hold(sdp, &dip->i_alloc.al_ri_gh);
  	if (error)
  		goto out_qs;
  
  	/*  Count the number of leaves  */

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

  		error = get_leaf(dip, blk, &bh);
  		if (error)
  			goto out_rlist;

  		tmp_leaf = (struct gfs2_leaf *)bh->b_data;
  		nblk = be64_to_cpu(tmp_leaf->lf_next);

  		brelse(bh);
  
  		gfs2_rlist_add(sdp, &rlist, blk);
  		l_blocks++;
  	}
  
  	gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE, 0);
  
  	for (x = 0; x < rlist.rl_rgrps; x++) {
  		struct gfs2_rgrpd *rgd;

  		rgd = rlist.rl_ghs[x].gh_gl->gl_object;

  		rg_blocks += rgd->rd_ri.ri_length;
  	}
  
  	error = gfs2_glock_nq_m(rlist.rl_rgrps, rlist.rl_ghs);
  	if (error)
  		goto out_rlist;
  
  	error = gfs2_trans_begin(sdp,

  			rg_blocks + (DIV_ROUND_UP(size, sdp->sd_jbsize) + 1) +

  			RES_DINODE + RES_STATFS + RES_QUOTA, l_blocks);
  	if (error)
  		goto out_rg_gunlock;

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

  		error = get_leaf(dip, blk, &bh);
  		if (error)
  			goto out_end_trans;

  		tmp_leaf = (struct gfs2_leaf *)bh->b_data;
  		nblk = be64_to_cpu(tmp_leaf->lf_next);

  		brelse(bh);
  
  		gfs2_free_meta(dip, blk, 1);
  
  		if (!dip->i_di.di_blocks)
  			gfs2_consist_inode(dip);
  		dip->i_di.di_blocks--;
  	}

  	error = gfs2_dir_write_data(dip, ht, index * sizeof(u64), size);

  	if (error != size) {
  		if (error >= 0)
  			error = -EIO;
  		goto out_end_trans;
  	}
  
  	error = gfs2_meta_inode_buffer(dip, &dibh);
  	if (error)
  		goto out_end_trans;

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

  	gfs2_dinode_out(&dip->i_di, dibh->b_data);
  	brelse(dibh);

  out_end_trans:

  	gfs2_trans_end(sdp);

  out_rg_gunlock:

  	gfs2_glock_dq_m(rlist.rl_rgrps, rlist.rl_ghs);

  out_rlist:

  	gfs2_rlist_free(&rlist);
  	gfs2_glock_dq_uninit(&dip->i_alloc.al_ri_gh);

  out_qs:

  	gfs2_quota_unhold(dip);

  out:

  	gfs2_alloc_put(dip);
  	kfree(ht);

  	return error;
  }
  
  /**
   * gfs2_dir_exhash_dealloc - free all the leaf blocks in a directory
   * @dip: the directory
   *
   * Dealloc all on-disk directory leaves to FREEMETA state
   * Change on-disk inode type to "regular file"
   *
   * Returns: errno
   */
  
  int gfs2_dir_exhash_dealloc(struct gfs2_inode *dip)
  {

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

  	struct buffer_head *bh;
  	int error;
  
  	/* Dealloc on-disk leaves to FREEMETA state */
  	error = foreach_leaf(dip, leaf_dealloc, NULL);
  	if (error)
  		return error;
  
  	/* Make this a regular file in case we crash.
  	   (We don't want to free these blocks a second time.)  */
  
  	error = gfs2_trans_begin(sdp, RES_DINODE, 0);
  	if (error)
  		return error;
  
  	error = gfs2_meta_inode_buffer(dip, &bh);
  	if (!error) {

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

  		((struct gfs2_dinode *)bh->b_data)->di_mode =
  						cpu_to_be32(S_IFREG);

  		brelse(bh);
  	}
  
  	gfs2_trans_end(sdp);
  
  	return error;
  }
  
  /**
   * gfs2_diradd_alloc_required - find if adding entry will require an allocation
   * @ip: the file being written to
   * @filname: the filename that's going to be added

   *

   * Returns: 1 if alloc required, 0 if not, -ve on error

   */

  int gfs2_diradd_alloc_required(struct inode *inode, const struct qstr *name)

  {

  	struct gfs2_dirent *dent;
  	struct buffer_head *bh;

  	dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space, &bh);

  	if (!dent) {

  		return 1;

  	}

  	if (IS_ERR(dent))
  		return PTR_ERR(dent);
  	brelse(bh);
  	return 0;

  }