dir.c

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/*
 * 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;
}



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;
}


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;
}

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;
}

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)\n", 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\n",
           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;
}

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;
}

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\n", leaf_no); */
        error = -EIO;
    }

    return error;
}

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 = "" };

    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;
}

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;
}

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\n", 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;
}

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;
}

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;
}

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)\n",
                    (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;
}

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);
    }
}

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)\n",
                (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;
}

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;
}

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;
}


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;
}

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;
}

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;

    error = gfs2_rindex_update(sdp);
    if (error)
        return error;

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

    ht = kzalloc(size, GFP_NOFS);
    if (!ht)
        return -ENOMEM;

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

    /*  Count the number of leaves  */
    bh = leaf_bh;

    for (blk = leaf_no; blk; blk = nblk) {
        if (blk != leaf_no) {
            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);
        if (blk != leaf_no)
            brelse(bh);

        gfs2_rlist_add(dip, &rlist, blk);
        l_blocks++;
    }

    gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE);

    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_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;

    bh = leaf_bh;

    for (blk = leaf_no; blk; blk = nblk) {
        if (blk != leaf_no) {
            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);
        if (blk != leaf_no)
            brelse(bh);

        gfs2_free_meta(dip, blk, 1);
        gfs2_add_inode_blocks(&dip->i_inode, -1);
    }

    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);
    /* On the last dealloc, make this a regular file in case we crash.
       (We don't want to free these blocks a second time.)  */
    if (last_dealloc)
        dip->i_inode.i_mode = S_IFREG;
    gfs2_dinode_out(dip, 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_quota_unhold(dip);
out:
    kfree(ht);
    return error;
}

int gfs2_dir_exhash_dealloc(struct gfs2_inode *dip)
{
    struct buffer_head *bh;
    struct gfs2_leaf *leaf;
    u32 hsize, len;
    u32 index = 0, next_index;
    __be64 *lp;
    u64 leaf_no;
    int error = 0, last;

    hsize = 1 << dip->i_depth;

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

    while (index < hsize) {
        leaf_no = be64_to_cpu(lp[index]);
        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_depth - be16_to_cpu(leaf->lf_depth));

            next_index = (index & ~(len - 1)) + len;
            last = ((next_index >= hsize) ? 1 : 0);
            error = leaf_dealloc(dip, index, len, leaf_no, bh,
                         last);
            brelse(bh);
            if (error)
                goto out;
            index = next_index;
        } else
            index++;
    }

    if (index != hsize) {
        gfs2_consist_inode(dip);
        error = -EIO;
    }

out:

    return 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;
}