gro: Allow tunnel stacking in the case of FOU/GUE

[linux/fpc-iii.git] / fs / ocfs2 / dir.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dir.c
 *
 * Creates, reads, walks and deletes directory-nodes
 *
 * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
 *
 *  Portions of this code from linux/fs/ext3/dir.c
 *
 *  Copyright (C) 1992, 1993, 1994, 1995
 *  Remy Card (card@masi.ibp.fr)
 *  Laboratoire MASI - Institut Blaise pascal
 *  Universite Pierre et Marie Curie (Paris VI)
 *
 *   from
 *
 *   linux/fs/minix/dir.c
 *
 *   Copyright (C) 1991, 1992 Linus Torvalds
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/quotaops.h>
#include <linux/sort.h>

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "blockcheck.h"
#include "dir.h"
#include "dlmglue.h"
#include "extent_map.h"
#include "file.h"
#include "inode.h"
#include "journal.h"
#include "namei.h"
#include "suballoc.h"
#include "super.h"
#include "sysfile.h"
#include "uptodate.h"
#include "ocfs2_trace.h"

#include "buffer_head_io.h"

#define NAMEI_RA_CHUNKS  2
#define NAMEI_RA_BLOCKS  4
#define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)

static unsigned char ocfs2_filetype_table[] = {
        DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
};

static int ocfs2_do_extend_dir(struct super_block *sb,
                               handle_t *handle,
                               struct inode *dir,
                               struct buffer_head *parent_fe_bh,
                               struct ocfs2_alloc_context *data_ac,
                               struct ocfs2_alloc_context *meta_ac,
                               struct buffer_head **new_bh);
static int ocfs2_dir_indexed(struct inode *inode);

/*
 * These are distinct checks because future versions of the file system will
 * want to have a trailing dirent structure independent of indexing.
 */
static int ocfs2_supports_dir_trailer(struct inode *dir)
{
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);

        if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
                return 0;

        return ocfs2_meta_ecc(osb) || ocfs2_dir_indexed(dir);
}

/*
 * "new' here refers to the point at which we're creating a new
 * directory via "mkdir()", but also when we're expanding an inline
 * directory. In either case, we don't yet have the indexing bit set
 * on the directory, so the standard checks will fail in when metaecc
 * is turned off. Only directory-initialization type functions should
 * use this then. Everything else wants ocfs2_supports_dir_trailer()
 */
static int ocfs2_new_dir_wants_trailer(struct inode *dir)
{
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);

        return ocfs2_meta_ecc(osb) ||
                ocfs2_supports_indexed_dirs(osb);
}

static inline unsigned int ocfs2_dir_trailer_blk_off(struct super_block *sb)
{
        return sb->s_blocksize - sizeof(struct ocfs2_dir_block_trailer);
}

#define ocfs2_trailer_from_bh(_bh, _sb) ((struct ocfs2_dir_block_trailer *) ((_bh)->b_data + ocfs2_dir_trailer_blk_off((_sb))))

/* XXX ocfs2_block_dqtrailer() is similar but not quite - can we make
 * them more consistent? */
struct ocfs2_dir_block_trailer *ocfs2_dir_trailer_from_size(int blocksize,
                                                            void *data)
{
        char *p = data;

        p += blocksize - sizeof(struct ocfs2_dir_block_trailer);
        return (struct ocfs2_dir_block_trailer *)p;
}

/*
 * XXX: This is executed once on every dirent. We should consider optimizing
 * it.
 */
static int ocfs2_skip_dir_trailer(struct inode *dir,
                                  struct ocfs2_dir_entry *de,
                                  unsigned long offset,
                                  unsigned long blklen)
{
        unsigned long toff = blklen - sizeof(struct ocfs2_dir_block_trailer);

        if (!ocfs2_supports_dir_trailer(dir))
                return 0;

        if (offset != toff)
                return 0;

        return 1;
}

static void ocfs2_init_dir_trailer(struct inode *inode,
                                   struct buffer_head *bh, u16 rec_len)
{
        struct ocfs2_dir_block_trailer *trailer;

        trailer = ocfs2_trailer_from_bh(bh, inode->i_sb);
        strcpy(trailer->db_signature, OCFS2_DIR_TRAILER_SIGNATURE);
        trailer->db_compat_rec_len =
                        cpu_to_le16(sizeof(struct ocfs2_dir_block_trailer));
        trailer->db_parent_dinode = cpu_to_le64(OCFS2_I(inode)->ip_blkno);
        trailer->db_blkno = cpu_to_le64(bh->b_blocknr);
        trailer->db_free_rec_len = cpu_to_le16(rec_len);
}
/*
 * Link an unindexed block with a dir trailer structure into the index free
 * list. This function will modify dirdata_bh, but assumes you've already
 * passed it to the journal.
 */
static int ocfs2_dx_dir_link_trailer(struct inode *dir, handle_t *handle,
                                     struct buffer_head *dx_root_bh,
                                     struct buffer_head *dirdata_bh)
{
        int ret;
        struct ocfs2_dx_root_block *dx_root;
        struct ocfs2_dir_block_trailer *trailer;

        ret = ocfs2_journal_access_dr(handle, INODE_CACHE(dir), dx_root_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
        trailer = ocfs2_trailer_from_bh(dirdata_bh, dir->i_sb);
        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;

        trailer->db_free_next = dx_root->dr_free_blk;
        dx_root->dr_free_blk = cpu_to_le64(dirdata_bh->b_blocknr);

        ocfs2_journal_dirty(handle, dx_root_bh);

out:
        return ret;
}

static int ocfs2_free_list_at_root(struct ocfs2_dir_lookup_result *res)
{
        return res->dl_prev_leaf_bh == NULL;
}

void ocfs2_free_dir_lookup_result(struct ocfs2_dir_lookup_result *res)
{
        brelse(res->dl_dx_root_bh);
        brelse(res->dl_leaf_bh);
        brelse(res->dl_dx_leaf_bh);
        brelse(res->dl_prev_leaf_bh);
}

static int ocfs2_dir_indexed(struct inode *inode)
{
        if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INDEXED_DIR_FL)
                return 1;
        return 0;
}

static inline int ocfs2_dx_root_inline(struct ocfs2_dx_root_block *dx_root)
{
        return dx_root->dr_flags & OCFS2_DX_FLAG_INLINE;
}

/*
 * Hashing code adapted from ext3
 */
#define DELTA 0x9E3779B9

static void TEA_transform(__u32 buf[4], __u32 const in[])
{
        __u32   sum = 0;
        __u32   b0 = buf[0], b1 = buf[1];
        __u32   a = in[0], b = in[1], c = in[2], d = in[3];
        int     n = 16;

        do {
                sum += DELTA;
                b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
                b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
        } while (--n);

        buf[0] += b0;
        buf[1] += b1;
}

static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
{
        __u32   pad, val;
        int     i;

        pad = (__u32)len | ((__u32)len << 8);
        pad |= pad << 16;

        val = pad;
        if (len > num*4)
                len = num * 4;
        for (i = 0; i < len; i++) {
                if ((i % 4) == 0)
                        val = pad;
                val = msg[i] + (val << 8);
                if ((i % 4) == 3) {
                        *buf++ = val;
                        val = pad;
                        num--;
                }
        }
        if (--num >= 0)
                *buf++ = val;
        while (--num >= 0)
                *buf++ = pad;
}

static void ocfs2_dx_dir_name_hash(struct inode *dir, const char *name, int len,
                                   struct ocfs2_dx_hinfo *hinfo)
{
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
        const char      *p;
        __u32           in[8], buf[4];

        /*
         * XXX: Is this really necessary, if the index is never looked
         * at by readdir? Is a hash value of '0' a bad idea?
         */
        if ((len == 1 && !strncmp(".", name, 1)) ||
            (len == 2 && !strncmp("..", name, 2))) {
                buf[0] = buf[1] = 0;
                goto out;
        }

#ifdef OCFS2_DEBUG_DX_DIRS
        /*
         * This makes it very easy to debug indexing problems. We
         * should never allow this to be selected without hand editing
         * this file though.
         */
        buf[0] = buf[1] = len;
        goto out;
#endif

        memcpy(buf, osb->osb_dx_seed, sizeof(buf));

        p = name;
        while (len > 0) {
                str2hashbuf(p, len, in, 4);
                TEA_transform(buf, in);
                len -= 16;
                p += 16;
        }

out:
        hinfo->major_hash = buf[0];
        hinfo->minor_hash = buf[1];
}

/*
 * bh passed here can be an inode block or a dir data block, depending
 * on the inode inline data flag.
 */
static int ocfs2_check_dir_entry(struct inode * dir,
                                 struct ocfs2_dir_entry * de,
                                 struct buffer_head * bh,
                                 unsigned long offset)
{
        const char *error_msg = NULL;
        const int rlen = le16_to_cpu(de->rec_len);

        if (unlikely(rlen < OCFS2_DIR_REC_LEN(1)))
                error_msg = "rec_len is smaller than minimal";
        else if (unlikely(rlen % 4 != 0))
                error_msg = "rec_len % 4 != 0";
        else if (unlikely(rlen < OCFS2_DIR_REC_LEN(de->name_len)))
                error_msg = "rec_len is too small for name_len";
        else if (unlikely(
                 ((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize))
                error_msg = "directory entry across blocks";

        if (unlikely(error_msg != NULL))
                mlog(ML_ERROR, "bad entry in directory #%llu: %s - "
                     "offset=%lu, inode=%llu, rec_len=%d, name_len=%d\n",
                     (unsigned long long)OCFS2_I(dir)->ip_blkno, error_msg,
                     offset, (unsigned long long)le64_to_cpu(de->inode), rlen,
                     de->name_len);

        return error_msg == NULL ? 1 : 0;
}

static inline int ocfs2_match(int len,
                              const char * const name,
                              struct ocfs2_dir_entry *de)
{
        if (len != de->name_len)
                return 0;
        if (!de->inode)
                return 0;
        return !memcmp(name, de->name, len);
}

/*
 * Returns 0 if not found, -1 on failure, and 1 on success
 */
static inline int ocfs2_search_dirblock(struct buffer_head *bh,
                                        struct inode *dir,
                                        const char *name, int namelen,
                                        unsigned long offset,
                                        char *first_de,
                                        unsigned int bytes,
                                        struct ocfs2_dir_entry **res_dir)
{
        struct ocfs2_dir_entry *de;
        char *dlimit, *de_buf;
        int de_len;
        int ret = 0;

        de_buf = first_de;
        dlimit = de_buf + bytes;

        while (de_buf < dlimit) {
                /* this code is executed quadratically often */
                /* do minimal checking `by hand' */

                de = (struct ocfs2_dir_entry *) de_buf;

                if (de_buf + namelen <= dlimit &&
                    ocfs2_match(namelen, name, de)) {
                        /* found a match - just to be sure, do a full check */
                        if (!ocfs2_check_dir_entry(dir, de, bh, offset)) {
                                ret = -1;
                                goto bail;
                        }
                        *res_dir = de;
                        ret = 1;
                        goto bail;
                }

                /* prevent looping on a bad block */
                de_len = le16_to_cpu(de->rec_len);
                if (de_len <= 0) {
                        ret = -1;
                        goto bail;
                }

                de_buf += de_len;
                offset += de_len;
        }

bail:
        trace_ocfs2_search_dirblock(ret);
        return ret;
}

static struct buffer_head *ocfs2_find_entry_id(const char *name,
                                               int namelen,
                                               struct inode *dir,
                                               struct ocfs2_dir_entry **res_dir)
{
        int ret, found;
        struct buffer_head *di_bh = NULL;
        struct ocfs2_dinode *di;
        struct ocfs2_inline_data *data;

        ret = ocfs2_read_inode_block(dir, &di_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        di = (struct ocfs2_dinode *)di_bh->b_data;
        data = &di->id2.i_data;

        found = ocfs2_search_dirblock(di_bh, dir, name, namelen, 0,
                                      data->id_data, i_size_read(dir), res_dir);
        if (found == 1)
                return di_bh;

        brelse(di_bh);
out:
        return NULL;
}

static int ocfs2_validate_dir_block(struct super_block *sb,
                                    struct buffer_head *bh)
{
        int rc;
        struct ocfs2_dir_block_trailer *trailer =
                ocfs2_trailer_from_bh(bh, sb);


        /*
         * We don't validate dirents here, that's handled
         * in-place when the code walks them.
         */
        trace_ocfs2_validate_dir_block((unsigned long long)bh->b_blocknr);

        BUG_ON(!buffer_uptodate(bh));

        /*
         * If the ecc fails, we return the error but otherwise
         * leave the filesystem running.  We know any error is
         * local to this block.
         *
         * Note that we are safe to call this even if the directory
         * doesn't have a trailer.  Filesystems without metaecc will do
         * nothing, and filesystems with it will have one.
         */
        rc = ocfs2_validate_meta_ecc(sb, bh->b_data, &trailer->db_check);
        if (rc)
                mlog(ML_ERROR, "Checksum failed for dinode %llu\n",
                     (unsigned long long)bh->b_blocknr);

        return rc;
}

/*
 * Validate a directory trailer.
 *
 * We check the trailer here rather than in ocfs2_validate_dir_block()
 * because that function doesn't have the inode to test.
 */
static int ocfs2_check_dir_trailer(struct inode *dir, struct buffer_head *bh)
{
        int rc = 0;
        struct ocfs2_dir_block_trailer *trailer;

        trailer = ocfs2_trailer_from_bh(bh, dir->i_sb);
        if (!OCFS2_IS_VALID_DIR_TRAILER(trailer)) {
                rc = -EINVAL;
                ocfs2_error(dir->i_sb,
                            "Invalid dirblock #%llu: "
                            "signature = %.*s\n",
                            (unsigned long long)bh->b_blocknr, 7,
                            trailer->db_signature);
                goto out;
        }
        if (le64_to_cpu(trailer->db_blkno) != bh->b_blocknr) {
                rc = -EINVAL;
                ocfs2_error(dir->i_sb,
                            "Directory block #%llu has an invalid "
                            "db_blkno of %llu",
                            (unsigned long long)bh->b_blocknr,
                            (unsigned long long)le64_to_cpu(trailer->db_blkno));
                goto out;
        }
        if (le64_to_cpu(trailer->db_parent_dinode) !=
            OCFS2_I(dir)->ip_blkno) {
                rc = -EINVAL;
                ocfs2_error(dir->i_sb,
                            "Directory block #%llu on dinode "
                            "#%llu has an invalid parent_dinode "
                            "of %llu",
                            (unsigned long long)bh->b_blocknr,
                            (unsigned long long)OCFS2_I(dir)->ip_blkno,
                            (unsigned long long)le64_to_cpu(trailer->db_blkno));
                goto out;
        }
out:
        return rc;
}

/*
 * This function forces all errors to -EIO for consistency with its
 * predecessor, ocfs2_bread().  We haven't audited what returning the
 * real error codes would do to callers.  We log the real codes with
 * mlog_errno() before we squash them.
 */
static int ocfs2_read_dir_block(struct inode *inode, u64 v_block,
                                struct buffer_head **bh, int flags)
{
        int rc = 0;
        struct buffer_head *tmp = *bh;

        rc = ocfs2_read_virt_blocks(inode, v_block, 1, &tmp, flags,
                                    ocfs2_validate_dir_block);
        if (rc) {
                mlog_errno(rc);
                goto out;
        }

        if (!(flags & OCFS2_BH_READAHEAD) &&
            ocfs2_supports_dir_trailer(inode)) {
                rc = ocfs2_check_dir_trailer(inode, tmp);
                if (rc) {
                        if (!*bh)
                                brelse(tmp);
                        mlog_errno(rc);
                        goto out;
                }
        }

        /* If ocfs2_read_virt_blocks() got us a new bh, pass it up. */
        if (!*bh)
                *bh = tmp;

out:
        return rc ? -EIO : 0;
}

/*
 * Read the block at 'phys' which belongs to this directory
 * inode. This function does no virtual->physical block translation -
 * what's passed in is assumed to be a valid directory block.
 */
static int ocfs2_read_dir_block_direct(struct inode *dir, u64 phys,
                                       struct buffer_head **bh)
{
        int ret;
        struct buffer_head *tmp = *bh;

        ret = ocfs2_read_block(INODE_CACHE(dir), phys, &tmp,
                               ocfs2_validate_dir_block);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        if (ocfs2_supports_dir_trailer(dir)) {
                ret = ocfs2_check_dir_trailer(dir, tmp);
                if (ret) {
                        if (!*bh)
                                brelse(tmp);
                        mlog_errno(ret);
                        goto out;
                }
        }

        if (!ret && !*bh)
                *bh = tmp;
out:
        return ret;
}

static int ocfs2_validate_dx_root(struct super_block *sb,
                                  struct buffer_head *bh)
{
        int ret;
        struct ocfs2_dx_root_block *dx_root;

        BUG_ON(!buffer_uptodate(bh));

        dx_root = (struct ocfs2_dx_root_block *) bh->b_data;

        ret = ocfs2_validate_meta_ecc(sb, bh->b_data, &dx_root->dr_check);
        if (ret) {
                mlog(ML_ERROR,
                     "Checksum failed for dir index root block %llu\n",
                     (unsigned long long)bh->b_blocknr);
                return ret;
        }

        if (!OCFS2_IS_VALID_DX_ROOT(dx_root)) {
                ocfs2_error(sb,
                            "Dir Index Root # %llu has bad signature %.*s",
                            (unsigned long long)le64_to_cpu(dx_root->dr_blkno),
                            7, dx_root->dr_signature);
                return -EINVAL;
        }

        return 0;
}

static int ocfs2_read_dx_root(struct inode *dir, struct ocfs2_dinode *di,
                              struct buffer_head **dx_root_bh)
{
        int ret;
        u64 blkno = le64_to_cpu(di->i_dx_root);
        struct buffer_head *tmp = *dx_root_bh;

        ret = ocfs2_read_block(INODE_CACHE(dir), blkno, &tmp,
                               ocfs2_validate_dx_root);

        /* If ocfs2_read_block() got us a new bh, pass it up. */
        if (!ret && !*dx_root_bh)
                *dx_root_bh = tmp;

        return ret;
}

static int ocfs2_validate_dx_leaf(struct super_block *sb,
                                  struct buffer_head *bh)
{
        int ret;
        struct ocfs2_dx_leaf *dx_leaf = (struct ocfs2_dx_leaf *)bh->b_data;

        BUG_ON(!buffer_uptodate(bh));

        ret = ocfs2_validate_meta_ecc(sb, bh->b_data, &dx_leaf->dl_check);
        if (ret) {
                mlog(ML_ERROR,
                     "Checksum failed for dir index leaf block %llu\n",
                     (unsigned long long)bh->b_blocknr);
                return ret;
        }

        if (!OCFS2_IS_VALID_DX_LEAF(dx_leaf)) {
                ocfs2_error(sb, "Dir Index Leaf has bad signature %.*s",
                            7, dx_leaf->dl_signature);
                return -EROFS;
        }

        return 0;
}

static int ocfs2_read_dx_leaf(struct inode *dir, u64 blkno,
                              struct buffer_head **dx_leaf_bh)
{
        int ret;
        struct buffer_head *tmp = *dx_leaf_bh;

        ret = ocfs2_read_block(INODE_CACHE(dir), blkno, &tmp,
                               ocfs2_validate_dx_leaf);

        /* If ocfs2_read_block() got us a new bh, pass it up. */
        if (!ret && !*dx_leaf_bh)
                *dx_leaf_bh = tmp;

        return ret;
}

/*
 * Read a series of dx_leaf blocks. This expects all buffer_head
 * pointers to be NULL on function entry.
 */
static int ocfs2_read_dx_leaves(struct inode *dir, u64 start, int num,
                                struct buffer_head **dx_leaf_bhs)
{
        int ret;

        ret = ocfs2_read_blocks(INODE_CACHE(dir), start, num, dx_leaf_bhs, 0,
                                ocfs2_validate_dx_leaf);
        if (ret)
                mlog_errno(ret);

        return ret;
}

static struct buffer_head *ocfs2_find_entry_el(const char *name, int namelen,
                                               struct inode *dir,
                                               struct ocfs2_dir_entry **res_dir)
{
        struct super_block *sb;
        struct buffer_head *bh_use[NAMEI_RA_SIZE];
        struct buffer_head *bh, *ret = NULL;
        unsigned long start, block, b;
        int ra_max = 0;         /* Number of bh's in the readahead
                                   buffer, bh_use[] */
        int ra_ptr = 0;         /* Current index into readahead
                                   buffer */
        int num = 0;
        int nblocks, i, err;

        sb = dir->i_sb;

        nblocks = i_size_read(dir) >> sb->s_blocksize_bits;
        start = OCFS2_I(dir)->ip_dir_start_lookup;
        if (start >= nblocks)
                start = 0;
        block = start;

restart:
        do {
                /*
                 * We deal with the read-ahead logic here.
                 */
                if (ra_ptr >= ra_max) {
                        /* Refill the readahead buffer */
                        ra_ptr = 0;
                        b = block;
                        for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) {
                                /*
                                 * Terminate if we reach the end of the
                                 * directory and must wrap, or if our
                                 * search has finished at this block.
                                 */
                                if (b >= nblocks || (num && block == start)) {
                                        bh_use[ra_max] = NULL;
                                        break;
                                }
                                num++;

                                bh = NULL;
                                err = ocfs2_read_dir_block(dir, b++, &bh,
                                                           OCFS2_BH_READAHEAD);
                                bh_use[ra_max] = bh;
                        }
                }
                if ((bh = bh_use[ra_ptr++]) == NULL)
                        goto next;
                if (ocfs2_read_dir_block(dir, block, &bh, 0)) {
                        /* read error, skip block & hope for the best.
                         * ocfs2_read_dir_block() has released the bh. */
                        mlog(ML_ERROR, "reading directory %llu, "
                                    "offset %lu\n",
                                    (unsigned long long)OCFS2_I(dir)->ip_blkno,
                                    block);
                        goto next;
                }
                i = ocfs2_search_dirblock(bh, dir, name, namelen,
                                          block << sb->s_blocksize_bits,
                                          bh->b_data, sb->s_blocksize,
                                          res_dir);
                if (i == 1) {
                        OCFS2_I(dir)->ip_dir_start_lookup = block;
                        ret = bh;
                        goto cleanup_and_exit;
                } else {
                        brelse(bh);
                        if (i < 0)
                                goto cleanup_and_exit;
                }
        next:
                if (++block >= nblocks)
                        block = 0;
        } while (block != start);

        /*
         * If the directory has grown while we were searching, then
         * search the last part of the directory before giving up.
         */
        block = nblocks;
        nblocks = i_size_read(dir) >> sb->s_blocksize_bits;
        if (block < nblocks) {
                start = 0;
                goto restart;
        }

cleanup_and_exit:
        /* Clean up the read-ahead blocks */
        for (; ra_ptr < ra_max; ra_ptr++)
                brelse(bh_use[ra_ptr]);

        trace_ocfs2_find_entry_el(ret);
        return ret;
}

static int ocfs2_dx_dir_lookup_rec(struct inode *inode,
                                   struct ocfs2_extent_list *el,
                                   u32 major_hash,
                                   u32 *ret_cpos,
                                   u64 *ret_phys_blkno,
                                   unsigned int *ret_clen)
{
        int ret = 0, i, found;
        struct buffer_head *eb_bh = NULL;
        struct ocfs2_extent_block *eb;
        struct ocfs2_extent_rec *rec = NULL;

        if (el->l_tree_depth) {
                ret = ocfs2_find_leaf(INODE_CACHE(inode), el, major_hash,
                                      &eb_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                eb = (struct ocfs2_extent_block *) eb_bh->b_data;
                el = &eb->h_list;

                if (el->l_tree_depth) {
                        ocfs2_error(inode->i_sb,
                                    "Inode %lu has non zero tree depth in "
                                    "btree tree block %llu\n", inode->i_ino,
                                    (unsigned long long)eb_bh->b_blocknr);
                        ret = -EROFS;
                        goto out;
                }
        }

        found = 0;
        for (i = le16_to_cpu(el->l_next_free_rec) - 1; i >= 0; i--) {
                rec = &el->l_recs[i];

                if (le32_to_cpu(rec->e_cpos) <= major_hash) {
                        found = 1;
                        break;
                }
        }

        if (!found) {
                ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
                            "record (%u, %u, 0) in btree", inode->i_ino,
                            le32_to_cpu(rec->e_cpos),
                            ocfs2_rec_clusters(el, rec));
                ret = -EROFS;
                goto out;
        }

        if (ret_phys_blkno)
                *ret_phys_blkno = le64_to_cpu(rec->e_blkno);
        if (ret_cpos)
                *ret_cpos = le32_to_cpu(rec->e_cpos);
        if (ret_clen)
                *ret_clen = le16_to_cpu(rec->e_leaf_clusters);

out:
        brelse(eb_bh);
        return ret;
}

/*
 * Returns the block index, from the start of the cluster which this
 * hash belongs too.
 */
static inline unsigned int __ocfs2_dx_dir_hash_idx(struct ocfs2_super *osb,
                                                   u32 minor_hash)
{
        return minor_hash & osb->osb_dx_mask;
}

static inline unsigned int ocfs2_dx_dir_hash_idx(struct ocfs2_super *osb,
                                          struct ocfs2_dx_hinfo *hinfo)
{
        return __ocfs2_dx_dir_hash_idx(osb, hinfo->minor_hash);
}

static int ocfs2_dx_dir_lookup(struct inode *inode,
                               struct ocfs2_extent_list *el,
                               struct ocfs2_dx_hinfo *hinfo,
                               u32 *ret_cpos,
                               u64 *ret_phys_blkno)
{
        int ret = 0;
        unsigned int cend, uninitialized_var(clen);
        u32 uninitialized_var(cpos);
        u64 uninitialized_var(blkno);
        u32 name_hash = hinfo->major_hash;

        ret = ocfs2_dx_dir_lookup_rec(inode, el, name_hash, &cpos, &blkno,
                                      &clen);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        cend = cpos + clen;
        if (name_hash >= cend) {
                /* We want the last cluster */
                blkno += ocfs2_clusters_to_blocks(inode->i_sb, clen - 1);
                cpos += clen - 1;
        } else {
                blkno += ocfs2_clusters_to_blocks(inode->i_sb,
                                                  name_hash - cpos);
                cpos = name_hash;
        }

        /*
         * We now have the cluster which should hold our entry. To
         * find the exact block from the start of the cluster to
         * search, we take the lower bits of the hash.
         */
        blkno += ocfs2_dx_dir_hash_idx(OCFS2_SB(inode->i_sb), hinfo);

        if (ret_phys_blkno)
                *ret_phys_blkno = blkno;
        if (ret_cpos)
                *ret_cpos = cpos;

out:

        return ret;
}

static int ocfs2_dx_dir_search(const char *name, int namelen,
                               struct inode *dir,
                               struct ocfs2_dx_root_block *dx_root,
                               struct ocfs2_dir_lookup_result *res)
{
        int ret, i, found;
        u64 uninitialized_var(phys);
        struct buffer_head *dx_leaf_bh = NULL;
        struct ocfs2_dx_leaf *dx_leaf;
        struct ocfs2_dx_entry *dx_entry = NULL;
        struct buffer_head *dir_ent_bh = NULL;
        struct ocfs2_dir_entry *dir_ent = NULL;
        struct ocfs2_dx_hinfo *hinfo = &res->dl_hinfo;
        struct ocfs2_extent_list *dr_el;
        struct ocfs2_dx_entry_list *entry_list;

        ocfs2_dx_dir_name_hash(dir, name, namelen, &res->dl_hinfo);

        if (ocfs2_dx_root_inline(dx_root)) {
                entry_list = &dx_root->dr_entries;
                goto search;
        }

        dr_el = &dx_root->dr_list;

        ret = ocfs2_dx_dir_lookup(dir, dr_el, hinfo, NULL, &phys);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        trace_ocfs2_dx_dir_search((unsigned long long)OCFS2_I(dir)->ip_blkno,
                                  namelen, name, hinfo->major_hash,
                                  hinfo->minor_hash, (unsigned long long)phys);

        ret = ocfs2_read_dx_leaf(dir, phys, &dx_leaf_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        dx_leaf = (struct ocfs2_dx_leaf *) dx_leaf_bh->b_data;

        trace_ocfs2_dx_dir_search_leaf_info(
                        le16_to_cpu(dx_leaf->dl_list.de_num_used),
                        le16_to_cpu(dx_leaf->dl_list.de_count));

        entry_list = &dx_leaf->dl_list;

search:
        /*
         * Empty leaf is legal, so no need to check for that.
         */
        found = 0;
        for (i = 0; i < le16_to_cpu(entry_list->de_num_used); i++) {
                dx_entry = &entry_list->de_entries[i];

                if (hinfo->major_hash != le32_to_cpu(dx_entry->dx_major_hash)
                    || hinfo->minor_hash != le32_to_cpu(dx_entry->dx_minor_hash))
                        continue;

                /*
                 * Search unindexed leaf block now. We're not
                 * guaranteed to find anything.
                 */
                ret = ocfs2_read_dir_block_direct(dir,
                                          le64_to_cpu(dx_entry->dx_dirent_blk),
                                          &dir_ent_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                /*
                 * XXX: We should check the unindexed block here,
                 * before using it.
                 */

                found = ocfs2_search_dirblock(dir_ent_bh, dir, name, namelen,
                                              0, dir_ent_bh->b_data,
                                              dir->i_sb->s_blocksize, &dir_ent);
                if (found == 1)
                        break;

                if (found == -1) {
                        /* This means we found a bad directory entry. */
                        ret = -EIO;
                        mlog_errno(ret);
                        goto out;
                }

                brelse(dir_ent_bh);
                dir_ent_bh = NULL;
        }

        if (found <= 0) {
                ret = -ENOENT;
                goto out;
        }

        res->dl_leaf_bh = dir_ent_bh;
        res->dl_entry = dir_ent;
        res->dl_dx_leaf_bh = dx_leaf_bh;
        res->dl_dx_entry = dx_entry;

        ret = 0;
out:
        if (ret) {
                brelse(dx_leaf_bh);
                brelse(dir_ent_bh);
        }
        return ret;
}

static int ocfs2_find_entry_dx(const char *name, int namelen,
                               struct inode *dir,
                               struct ocfs2_dir_lookup_result *lookup)
{
        int ret;
        struct buffer_head *di_bh = NULL;
        struct ocfs2_dinode *di;
        struct buffer_head *dx_root_bh = NULL;
        struct ocfs2_dx_root_block *dx_root;

        ret = ocfs2_read_inode_block(dir, &di_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        di = (struct ocfs2_dinode *)di_bh->b_data;

        ret = ocfs2_read_dx_root(dir, di, &dx_root_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
        dx_root = (struct ocfs2_dx_root_block *) dx_root_bh->b_data;

        ret = ocfs2_dx_dir_search(name, namelen, dir, dx_root, lookup);
        if (ret) {
                if (ret != -ENOENT)
                        mlog_errno(ret);
                goto out;
        }

        lookup->dl_dx_root_bh = dx_root_bh;
        dx_root_bh = NULL;
out:
        brelse(di_bh);
        brelse(dx_root_bh);
        return ret;
}

/*
 * Try to find an entry of the provided name within 'dir'.
 *
 * If nothing was found, -ENOENT is returned. Otherwise, zero is
 * returned and the struct 'res' will contain information useful to
 * other directory manipulation functions.
 *
 * Caller can NOT assume anything about the contents of the
 * buffer_heads - they are passed back only so that it can be passed
 * into any one of the manipulation functions (add entry, delete
 * entry, etc). As an example, bh in the extent directory case is a
 * data block, in the inline-data case it actually points to an inode,
 * in the indexed directory case, multiple buffers are involved.
 */
int ocfs2_find_entry(const char *name, int namelen,
                     struct inode *dir, struct ocfs2_dir_lookup_result *lookup)
{
        struct buffer_head *bh;
        struct ocfs2_dir_entry *res_dir = NULL;

        if (ocfs2_dir_indexed(dir))
                return ocfs2_find_entry_dx(name, namelen, dir, lookup);

        /*
         * The unindexed dir code only uses part of the lookup
         * structure, so there's no reason to push it down further
         * than this.
         */
        if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
                bh = ocfs2_find_entry_id(name, namelen, dir, &res_dir);
        else
                bh = ocfs2_find_entry_el(name, namelen, dir, &res_dir);

        if (bh == NULL)
                return -ENOENT;

        lookup->dl_leaf_bh = bh;
        lookup->dl_entry = res_dir;
        return 0;
}

/*
 * Update inode number and type of a previously found directory entry.
 */
int ocfs2_update_entry(struct inode *dir, handle_t *handle,
                       struct ocfs2_dir_lookup_result *res,
                       struct inode *new_entry_inode)
{
        int ret;
        ocfs2_journal_access_func access = ocfs2_journal_access_db;
        struct ocfs2_dir_entry *de = res->dl_entry;
        struct buffer_head *de_bh = res->dl_leaf_bh;

        /*
         * The same code works fine for both inline-data and extent
         * based directories, so no need to split this up.  The only
         * difference is the journal_access function.
         */

        if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
                access = ocfs2_journal_access_di;

        ret = access(handle, INODE_CACHE(dir), de_bh,
                     OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        de->inode = cpu_to_le64(OCFS2_I(new_entry_inode)->ip_blkno);
        ocfs2_set_de_type(de, new_entry_inode->i_mode);

        ocfs2_journal_dirty(handle, de_bh);

out:
        return ret;
}

/*
 * __ocfs2_delete_entry deletes a directory entry by merging it with the
 * previous entry
 */
static int __ocfs2_delete_entry(handle_t *handle, struct inode *dir,
                                struct ocfs2_dir_entry *de_del,
                                struct buffer_head *bh, char *first_de,
                                unsigned int bytes)
{
        struct ocfs2_dir_entry *de, *pde;
        int i, status = -ENOENT;
        ocfs2_journal_access_func access = ocfs2_journal_access_db;

        if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
                access = ocfs2_journal_access_di;

        i = 0;
        pde = NULL;
        de = (struct ocfs2_dir_entry *) first_de;
        while (i < bytes) {
                if (!ocfs2_check_dir_entry(dir, de, bh, i)) {
                        status = -EIO;
                        mlog_errno(status);
                        goto bail;
                }
                if (de == de_del)  {
                        status = access(handle, INODE_CACHE(dir), bh,
                                        OCFS2_JOURNAL_ACCESS_WRITE);
                        if (status < 0) {
                                status = -EIO;
                                mlog_errno(status);
                                goto bail;
                        }
                        if (pde)
                                le16_add_cpu(&pde->rec_len,
                                                le16_to_cpu(de->rec_len));
                        de->inode = 0;
                        dir->i_version++;
                        ocfs2_journal_dirty(handle, bh);
                        goto bail;
                }
                i += le16_to_cpu(de->rec_len);
                pde = de;
                de = (struct ocfs2_dir_entry *)((char *)de + le16_to_cpu(de->rec_len));
        }
bail:
        return status;
}

static unsigned int ocfs2_figure_dirent_hole(struct ocfs2_dir_entry *de)
{
        unsigned int hole;

        if (le64_to_cpu(de->inode) == 0)
                hole = le16_to_cpu(de->rec_len);
        else
                hole = le16_to_cpu(de->rec_len) -
                        OCFS2_DIR_REC_LEN(de->name_len);

        return hole;
}

static int ocfs2_find_max_rec_len(struct super_block *sb,
                                  struct buffer_head *dirblock_bh)
{
        int size, this_hole, largest_hole = 0;
        char *trailer, *de_buf, *limit, *start = dirblock_bh->b_data;
        struct ocfs2_dir_entry *de;

        trailer = (char *)ocfs2_trailer_from_bh(dirblock_bh, sb);
        size = ocfs2_dir_trailer_blk_off(sb);
        limit = start + size;
        de_buf = start;
        de = (struct ocfs2_dir_entry *)de_buf;
        do {
                if (de_buf != trailer) {
                        this_hole = ocfs2_figure_dirent_hole(de);
                        if (this_hole > largest_hole)
                                largest_hole = this_hole;
                }

                de_buf += le16_to_cpu(de->rec_len);
                de = (struct ocfs2_dir_entry *)de_buf;
        } while (de_buf < limit);

        if (largest_hole >= OCFS2_DIR_MIN_REC_LEN)
                return largest_hole;
        return 0;
}

static void ocfs2_dx_list_remove_entry(struct ocfs2_dx_entry_list *entry_list,
                                       int index)
{
        int num_used = le16_to_cpu(entry_list->de_num_used);

        if (num_used == 1 || index == (num_used - 1))
                goto clear;

        memmove(&entry_list->de_entries[index],
                &entry_list->de_entries[index + 1],
                (num_used - index - 1)*sizeof(struct ocfs2_dx_entry));
clear:
        num_used--;
        memset(&entry_list->de_entries[num_used], 0,
               sizeof(struct ocfs2_dx_entry));
        entry_list->de_num_used = cpu_to_le16(num_used);
}

static int ocfs2_delete_entry_dx(handle_t *handle, struct inode *dir,
                                 struct ocfs2_dir_lookup_result *lookup)
{
        int ret, index, max_rec_len, add_to_free_list = 0;
        struct buffer_head *dx_root_bh = lookup->dl_dx_root_bh;
        struct buffer_head *leaf_bh = lookup->dl_leaf_bh;
        struct ocfs2_dx_leaf *dx_leaf;
        struct ocfs2_dx_entry *dx_entry = lookup->dl_dx_entry;
        struct ocfs2_dir_block_trailer *trailer;
        struct ocfs2_dx_root_block *dx_root;
        struct ocfs2_dx_entry_list *entry_list;

        /*
         * This function gets a bit messy because we might have to
         * modify the root block, regardless of whether the indexed
         * entries are stored inline.
         */

        /*
         * *Only* set 'entry_list' here, based on where we're looking
         * for the indexed entries. Later, we might still want to
         * journal both blocks, based on free list state.
         */
        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;
        if (ocfs2_dx_root_inline(dx_root)) {
                entry_list = &dx_root->dr_entries;
        } else {
                dx_leaf = (struct ocfs2_dx_leaf *) lookup->dl_dx_leaf_bh->b_data;
                entry_list = &dx_leaf->dl_list;
        }

        /* Neither of these are a disk corruption - that should have
         * been caught by lookup, before we got here. */
        BUG_ON(le16_to_cpu(entry_list->de_count) <= 0);
        BUG_ON(le16_to_cpu(entry_list->de_num_used) <= 0);

        index = (char *)dx_entry - (char *)entry_list->de_entries;
        index /= sizeof(*dx_entry);

        if (index >= le16_to_cpu(entry_list->de_num_used)) {
                mlog(ML_ERROR, "Dir %llu: Bad dx_entry ptr idx %d, (%p, %p)\n",
                     (unsigned long long)OCFS2_I(dir)->ip_blkno, index,
                     entry_list, dx_entry);
                return -EIO;
        }

        /*
         * We know that removal of this dirent will leave enough room
         * for a new one, so add this block to the free list if it
         * isn't already there.
         */
        trailer = ocfs2_trailer_from_bh(leaf_bh, dir->i_sb);
        if (trailer->db_free_rec_len == 0)
                add_to_free_list = 1;

        /*
         * Add the block holding our index into the journal before
         * removing the unindexed entry. If we get an error return
         * from __ocfs2_delete_entry(), then it hasn't removed the
         * entry yet. Likewise, successful return means we *must*
         * remove the indexed entry.
         *
         * We're also careful to journal the root tree block here as
         * the entry count needs to be updated. Also, we might be
         * adding to the start of the free list.
         */
        ret = ocfs2_journal_access_dr(handle, INODE_CACHE(dir), dx_root_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        if (!ocfs2_dx_root_inline(dx_root)) {
                ret = ocfs2_journal_access_dl(handle, INODE_CACHE(dir),
                                              lookup->dl_dx_leaf_bh,
                                              OCFS2_JOURNAL_ACCESS_WRITE);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }
        }

        trace_ocfs2_delete_entry_dx((unsigned long long)OCFS2_I(dir)->ip_blkno,
                                    index);

        ret = __ocfs2_delete_entry(handle, dir, lookup->dl_entry,
                                   leaf_bh, leaf_bh->b_data, leaf_bh->b_size);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        max_rec_len = ocfs2_find_max_rec_len(dir->i_sb, leaf_bh);
        trailer->db_free_rec_len = cpu_to_le16(max_rec_len);
        if (add_to_free_list) {
                trailer->db_free_next = dx_root->dr_free_blk;
                dx_root->dr_free_blk = cpu_to_le64(leaf_bh->b_blocknr);
                ocfs2_journal_dirty(handle, dx_root_bh);
        }

        /* leaf_bh was journal_accessed for us in __ocfs2_delete_entry */
        ocfs2_journal_dirty(handle, leaf_bh);

        le32_add_cpu(&dx_root->dr_num_entries, -1);
        ocfs2_journal_dirty(handle, dx_root_bh);

        ocfs2_dx_list_remove_entry(entry_list, index);

        if (!ocfs2_dx_root_inline(dx_root))
                ocfs2_journal_dirty(handle, lookup->dl_dx_leaf_bh);

out:
        return ret;
}

static inline int ocfs2_delete_entry_id(handle_t *handle,
                                        struct inode *dir,
                                        struct ocfs2_dir_entry *de_del,
                                        struct buffer_head *bh)
{
        int ret;
        struct buffer_head *di_bh = NULL;
        struct ocfs2_dinode *di;
        struct ocfs2_inline_data *data;

        ret = ocfs2_read_inode_block(dir, &di_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        di = (struct ocfs2_dinode *)di_bh->b_data;
        data = &di->id2.i_data;

        ret = __ocfs2_delete_entry(handle, dir, de_del, bh, data->id_data,
                                   i_size_read(dir));

        brelse(di_bh);
out:
        return ret;
}

static inline int ocfs2_delete_entry_el(handle_t *handle,
                                        struct inode *dir,
                                        struct ocfs2_dir_entry *de_del,
                                        struct buffer_head *bh)
{
        return __ocfs2_delete_entry(handle, dir, de_del, bh, bh->b_data,
                                    bh->b_size);
}

/*
 * Delete a directory entry. Hide the details of directory
 * implementation from the caller.
 */
int ocfs2_delete_entry(handle_t *handle,
                       struct inode *dir,
                       struct ocfs2_dir_lookup_result *res)
{
        if (ocfs2_dir_indexed(dir))
                return ocfs2_delete_entry_dx(handle, dir, res);

        if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
                return ocfs2_delete_entry_id(handle, dir, res->dl_entry,
                                             res->dl_leaf_bh);

        return ocfs2_delete_entry_el(handle, dir, res->dl_entry,
                                     res->dl_leaf_bh);
}

/*
 * Check whether 'de' has enough room to hold an entry of
 * 'new_rec_len' bytes.
 */
static inline int ocfs2_dirent_would_fit(struct ocfs2_dir_entry *de,
                                         unsigned int new_rec_len)
{
        unsigned int de_really_used;

        /* Check whether this is an empty record with enough space */
        if (le64_to_cpu(de->inode) == 0 &&
            le16_to_cpu(de->rec_len) >= new_rec_len)
                return 1;

        /*
         * Record might have free space at the end which we can
         * use.
         */
        de_really_used = OCFS2_DIR_REC_LEN(de->name_len);
        if (le16_to_cpu(de->rec_len) >= (de_really_used + new_rec_len))
            return 1;

        return 0;
}

static void ocfs2_dx_dir_leaf_insert_tail(struct ocfs2_dx_leaf *dx_leaf,
                                          struct ocfs2_dx_entry *dx_new_entry)
{
        int i;

        i = le16_to_cpu(dx_leaf->dl_list.de_num_used);
        dx_leaf->dl_list.de_entries[i] = *dx_new_entry;

        le16_add_cpu(&dx_leaf->dl_list.de_num_used, 1);
}

static void ocfs2_dx_entry_list_insert(struct ocfs2_dx_entry_list *entry_list,
                                       struct ocfs2_dx_hinfo *hinfo,
                                       u64 dirent_blk)
{
        int i;
        struct ocfs2_dx_entry *dx_entry;

        i = le16_to_cpu(entry_list->de_num_used);
        dx_entry = &entry_list->de_entries[i];

        memset(dx_entry, 0, sizeof(*dx_entry));
        dx_entry->dx_major_hash = cpu_to_le32(hinfo->major_hash);
        dx_entry->dx_minor_hash = cpu_to_le32(hinfo->minor_hash);
        dx_entry->dx_dirent_blk = cpu_to_le64(dirent_blk);

        le16_add_cpu(&entry_list->de_num_used, 1);
}

static int __ocfs2_dx_dir_leaf_insert(struct inode *dir, handle_t *handle,
                                      struct ocfs2_dx_hinfo *hinfo,
                                      u64 dirent_blk,
                                      struct buffer_head *dx_leaf_bh)
{
        int ret;
        struct ocfs2_dx_leaf *dx_leaf;

        ret = ocfs2_journal_access_dl(handle, INODE_CACHE(dir), dx_leaf_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        dx_leaf = (struct ocfs2_dx_leaf *)dx_leaf_bh->b_data;
        ocfs2_dx_entry_list_insert(&dx_leaf->dl_list, hinfo, dirent_blk);
        ocfs2_journal_dirty(handle, dx_leaf_bh);

out:
        return ret;
}

static void ocfs2_dx_inline_root_insert(struct inode *dir, handle_t *handle,
                                        struct ocfs2_dx_hinfo *hinfo,
                                        u64 dirent_blk,
                                        struct ocfs2_dx_root_block *dx_root)
{
        ocfs2_dx_entry_list_insert(&dx_root->dr_entries, hinfo, dirent_blk);
}

static int ocfs2_dx_dir_insert(struct inode *dir, handle_t *handle,
                               struct ocfs2_dir_lookup_result *lookup)
{
        int ret = 0;
        struct ocfs2_dx_root_block *dx_root;
        struct buffer_head *dx_root_bh = lookup->dl_dx_root_bh;

        ret = ocfs2_journal_access_dr(handle, INODE_CACHE(dir), dx_root_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        dx_root = (struct ocfs2_dx_root_block *)lookup->dl_dx_root_bh->b_data;
        if (ocfs2_dx_root_inline(dx_root)) {
                ocfs2_dx_inline_root_insert(dir, handle,
                                            &lookup->dl_hinfo,
                                            lookup->dl_leaf_bh->b_blocknr,
                                            dx_root);
        } else {
                ret = __ocfs2_dx_dir_leaf_insert(dir, handle, &lookup->dl_hinfo,
                                                 lookup->dl_leaf_bh->b_blocknr,
                                                 lookup->dl_dx_leaf_bh);
                if (ret)
                        goto out;
        }

        le32_add_cpu(&dx_root->dr_num_entries, 1);
        ocfs2_journal_dirty(handle, dx_root_bh);

out:
        return ret;
}

static void ocfs2_remove_block_from_free_list(struct inode *dir,
                                       handle_t *handle,
                                       struct ocfs2_dir_lookup_result *lookup)
{
        struct ocfs2_dir_block_trailer *trailer, *prev;
        struct ocfs2_dx_root_block *dx_root;
        struct buffer_head *bh;

        trailer = ocfs2_trailer_from_bh(lookup->dl_leaf_bh, dir->i_sb);

        if (ocfs2_free_list_at_root(lookup)) {
                bh = lookup->dl_dx_root_bh;
                dx_root = (struct ocfs2_dx_root_block *)bh->b_data;
                dx_root->dr_free_blk = trailer->db_free_next;
        } else {
                bh = lookup->dl_prev_leaf_bh;
                prev = ocfs2_trailer_from_bh(bh, dir->i_sb);
                prev->db_free_next = trailer->db_free_next;
        }

        trailer->db_free_rec_len = cpu_to_le16(0);
        trailer->db_free_next = cpu_to_le64(0);

        ocfs2_journal_dirty(handle, bh);
        ocfs2_journal_dirty(handle, lookup->dl_leaf_bh);
}

/*
 * This expects that a journal write has been reserved on
 * lookup->dl_prev_leaf_bh or lookup->dl_dx_root_bh
 */
static void ocfs2_recalc_free_list(struct inode *dir, handle_t *handle,
                                   struct ocfs2_dir_lookup_result *lookup)
{
        int max_rec_len;
        struct ocfs2_dir_block_trailer *trailer;

        /* Walk dl_leaf_bh to figure out what the new free rec_len is. */
        max_rec_len = ocfs2_find_max_rec_len(dir->i_sb, lookup->dl_leaf_bh);
        if (max_rec_len) {
                /*
                 * There's still room in this block, so no need to remove it
                 * from the free list. In this case, we just want to update
                 * the rec len accounting.
                 */
                trailer = ocfs2_trailer_from_bh(lookup->dl_leaf_bh, dir->i_sb);
                trailer->db_free_rec_len = cpu_to_le16(max_rec_len);
                ocfs2_journal_dirty(handle, lookup->dl_leaf_bh);
        } else {
                ocfs2_remove_block_from_free_list(dir, handle, lookup);
        }
}

/* we don't always have a dentry for what we want to add, so people
 * like orphan dir can call this instead.
 *
 * The lookup context must have been filled from
 * ocfs2_prepare_dir_for_insert.
 */
int __ocfs2_add_entry(handle_t *handle,
                      struct inode *dir,
                      const char *name, int namelen,
                      struct inode *inode, u64 blkno,
                      struct buffer_head *parent_fe_bh,
                      struct ocfs2_dir_lookup_result *lookup)
{
        unsigned long offset;
        unsigned short rec_len;
        struct ocfs2_dir_entry *de, *de1;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)parent_fe_bh->b_data;
        struct super_block *sb = dir->i_sb;
        int retval, status;
        unsigned int size = sb->s_blocksize;
        struct buffer_head *insert_bh = lookup->dl_leaf_bh;
        char *data_start = insert_bh->b_data;

        if (!namelen)
                return -EINVAL;

        if (ocfs2_dir_indexed(dir)) {
                struct buffer_head *bh;

                /*
                 * An indexed dir may require that we update the free space
                 * list. Reserve a write to the previous node in the list so
                 * that we don't fail later.
                 *
                 * XXX: This can be either a dx_root_block, or an unindexed
                 * directory tree leaf block.
                 */
                if (ocfs2_free_list_at_root(lookup)) {
                        bh = lookup->dl_dx_root_bh;
                        retval = ocfs2_journal_access_dr(handle,
                                                 INODE_CACHE(dir), bh,
                                                 OCFS2_JOURNAL_ACCESS_WRITE);
                } else {
                        bh = lookup->dl_prev_leaf_bh;
                        retval = ocfs2_journal_access_db(handle,
                                                 INODE_CACHE(dir), bh,
                                                 OCFS2_JOURNAL_ACCESS_WRITE);
                }
                if (retval) {
                        mlog_errno(retval);
                        return retval;
                }
        } else if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
                data_start = di->id2.i_data.id_data;
                size = i_size_read(dir);

                BUG_ON(insert_bh != parent_fe_bh);
        }

        rec_len = OCFS2_DIR_REC_LEN(namelen);
        offset = 0;
        de = (struct ocfs2_dir_entry *) data_start;
        while (1) {
                BUG_ON((char *)de >= (size + data_start));

                /* These checks should've already been passed by the
                 * prepare function, but I guess we can leave them
                 * here anyway. */
                if (!ocfs2_check_dir_entry(dir, de, insert_bh, offset)) {
                        retval = -ENOENT;
                        goto bail;
                }
                if (ocfs2_match(namelen, name, de)) {
                        retval = -EEXIST;
                        goto bail;
                }

                /* We're guaranteed that we should have space, so we
                 * can't possibly have hit the trailer...right? */
                mlog_bug_on_msg(ocfs2_skip_dir_trailer(dir, de, offset, size),
                                "Hit dir trailer trying to insert %.*s "
                                "(namelen %d) into directory %llu.  "
                                "offset is %lu, trailer offset is %d\n",
                                namelen, name, namelen,
                                (unsigned long long)parent_fe_bh->b_blocknr,
                                offset, ocfs2_dir_trailer_blk_off(dir->i_sb));

                if (ocfs2_dirent_would_fit(de, rec_len)) {
                        dir->i_mtime = dir->i_ctime = CURRENT_TIME;
                        retval = ocfs2_mark_inode_dirty(handle, dir, parent_fe_bh);
                        if (retval < 0) {
                                mlog_errno(retval);
                                goto bail;
                        }

                        if (insert_bh == parent_fe_bh)
                                status = ocfs2_journal_access_di(handle,
                                                                 INODE_CACHE(dir),
                                                                 insert_bh,
                                                                 OCFS2_JOURNAL_ACCESS_WRITE);
                        else {
                                status = ocfs2_journal_access_db(handle,
                                                                 INODE_CACHE(dir),
                                                                 insert_bh,
                                              OCFS2_JOURNAL_ACCESS_WRITE);

                                if (ocfs2_dir_indexed(dir)) {
                                        status = ocfs2_dx_dir_insert(dir,
                                                                handle,
                                                                lookup);
                                        if (status) {
                                                mlog_errno(status);
                                                goto bail;
                                        }
                                }
                        }

                        /* By now the buffer is marked for journaling */
                        offset += le16_to_cpu(de->rec_len);
                        if (le64_to_cpu(de->inode)) {
                                de1 = (struct ocfs2_dir_entry *)((char *) de +
                                        OCFS2_DIR_REC_LEN(de->name_len));
                                de1->rec_len =
                                        cpu_to_le16(le16_to_cpu(de->rec_len) -
                                        OCFS2_DIR_REC_LEN(de->name_len));
                                de->rec_len = cpu_to_le16(OCFS2_DIR_REC_LEN(de->name_len));
                                de = de1;
                        }
                        de->file_type = OCFS2_FT_UNKNOWN;
                        if (blkno) {
                                de->inode = cpu_to_le64(blkno);
                                ocfs2_set_de_type(de, inode->i_mode);
                        } else
                                de->inode = 0;
                        de->name_len = namelen;
                        memcpy(de->name, name, namelen);

                        if (ocfs2_dir_indexed(dir))
                                ocfs2_recalc_free_list(dir, handle, lookup);

                        dir->i_version++;
                        ocfs2_journal_dirty(handle, insert_bh);
                        retval = 0;
                        goto bail;
                }

                offset += le16_to_cpu(de->rec_len);
                de = (struct ocfs2_dir_entry *) ((char *) de + le16_to_cpu(de->rec_len));
        }

        /* when you think about it, the assert above should prevent us
         * from ever getting here. */
        retval = -ENOSPC;
bail:
        if (retval)
                mlog_errno(retval);

        return retval;
}

static int ocfs2_dir_foreach_blk_id(struct inode *inode,
                                    u64 *f_version,
                                    struct dir_context *ctx)
{
        int ret, i;
        unsigned long offset = ctx->pos;
        struct buffer_head *di_bh = NULL;
        struct ocfs2_dinode *di;
        struct ocfs2_inline_data *data;
        struct ocfs2_dir_entry *de;

        ret = ocfs2_read_inode_block(inode, &di_bh);
        if (ret) {
                mlog(ML_ERROR, "Unable to read inode block for dir %llu\n",
                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
                goto out;
        }

        di = (struct ocfs2_dinode *)di_bh->b_data;
        data = &di->id2.i_data;

        while (ctx->pos < i_size_read(inode)) {
                /* If the dir block has changed since the last call to
                 * readdir(2), then we might be pointing to an invalid
                 * dirent right now.  Scan from the start of the block
                 * to make sure. */
                if (*f_version != inode->i_version) {
                        for (i = 0; i < i_size_read(inode) && i < offset; ) {
                                de = (struct ocfs2_dir_entry *)
                                        (data->id_data + i);
                                /* It's too expensive to do a full
                                 * dirent test each time round this
                                 * loop, but we do have to test at
                                 * least that it is non-zero.  A
                                 * failure will be detected in the
                                 * dirent test below. */
                                if (le16_to_cpu(de->rec_len) <
                                    OCFS2_DIR_REC_LEN(1))
                                        break;
                                i += le16_to_cpu(de->rec_len);
                        }
                        ctx->pos = offset = i;
                        *f_version = inode->i_version;
                }

                de = (struct ocfs2_dir_entry *) (data->id_data + ctx->pos);
                if (!ocfs2_check_dir_entry(inode, de, di_bh, ctx->pos)) {
                        /* On error, skip the f_pos to the end. */
                        ctx->pos = i_size_read(inode);
                        break;
                }
                offset += le16_to_cpu(de->rec_len);
                if (le64_to_cpu(de->inode)) {
                        unsigned char d_type = DT_UNKNOWN;

                        if (de->file_type < OCFS2_FT_MAX)
                                d_type = ocfs2_filetype_table[de->file_type];

                        if (!dir_emit(ctx, de->name, de->name_len,
                                      le64_to_cpu(de->inode), d_type))
                                goto out;
                }
                ctx->pos += le16_to_cpu(de->rec_len);
        }
out:
        brelse(di_bh);
        return 0;
}

/*
 * NOTE: This function can be called against unindexed directories,
 * and indexed ones.
 */
static int ocfs2_dir_foreach_blk_el(struct inode *inode,
                                    u64 *f_version,
                                    struct dir_context *ctx,
                                    bool persist)
{
        unsigned long offset, blk, last_ra_blk = 0;
        int i;
        struct buffer_head * bh, * tmp;
        struct ocfs2_dir_entry * de;
        struct super_block * sb = inode->i_sb;
        unsigned int ra_sectors = 16;
        int stored = 0;

        bh = NULL;

        offset = ctx->pos & (sb->s_blocksize - 1);

        while (ctx->pos < i_size_read(inode)) {
                blk = ctx->pos >> sb->s_blocksize_bits;
                if (ocfs2_read_dir_block(inode, blk, &bh, 0)) {
                        /* Skip the corrupt dirblock and keep trying */
                        ctx->pos += sb->s_blocksize - offset;
                        continue;
                }

                /* The idea here is to begin with 8k read-ahead and to stay
                 * 4k ahead of our current position.
                 *
                 * TODO: Use the pagecache for this. We just need to
                 * make sure it's cluster-safe... */
                if (!last_ra_blk
                    || (((last_ra_blk - blk) << 9) <= (ra_sectors / 2))) {
                        for (i = ra_sectors >> (sb->s_blocksize_bits - 9);
                             i > 0; i--) {
                                tmp = NULL;
                                if (!ocfs2_read_dir_block(inode, ++blk, &tmp,
                                                          OCFS2_BH_READAHEAD))
                                        brelse(tmp);
                        }
                        last_ra_blk = blk;
                        ra_sectors = 8;
                }

                /* If the dir block has changed since the last call to
                 * readdir(2), then we might be pointing to an invalid
                 * dirent right now.  Scan from the start of the block
                 * to make sure. */
                if (*f_version != inode->i_version) {
                        for (i = 0; i < sb->s_blocksize && i < offset; ) {
                                de = (struct ocfs2_dir_entry *) (bh->b_data + i);
                                /* It's too expensive to do a full
                                 * dirent test each time round this
                                 * loop, but we do have to test at
                                 * least that it is non-zero.  A
                                 * failure will be detected in the
                                 * dirent test below. */
                                if (le16_to_cpu(de->rec_len) <
                                    OCFS2_DIR_REC_LEN(1))
                                        break;
                                i += le16_to_cpu(de->rec_len);
                        }
                        offset = i;
                        ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
                                | offset;
                        *f_version = inode->i_version;
                }

                while (ctx->pos < i_size_read(inode)
                       && offset < sb->s_blocksize) {
                        de = (struct ocfs2_dir_entry *) (bh->b_data + offset);
                        if (!ocfs2_check_dir_entry(inode, de, bh, offset)) {
                                /* On error, skip the f_pos to the
                                   next block. */
                                ctx->pos = (ctx->pos | (sb->s_blocksize - 1)) + 1;
                                brelse(bh);
                                continue;
                        }
                        if (le64_to_cpu(de->inode)) {
                                unsigned char d_type = DT_UNKNOWN;

                                if (de->file_type < OCFS2_FT_MAX)
                                        d_type = ocfs2_filetype_table[de->file_type];
                                if (!dir_emit(ctx, de->name,
                                                de->name_len,
                                                le64_to_cpu(de->inode),
                                                d_type)) {
                                        brelse(bh);
                                        return 0;
                                }
                                stored++;
                        }
                        offset += le16_to_cpu(de->rec_len);
                        ctx->pos += le16_to_cpu(de->rec_len);
                }
                offset = 0;
                brelse(bh);
                bh = NULL;
                if (!persist && stored)
                        break;
        }
        return 0;
}

static int ocfs2_dir_foreach_blk(struct inode *inode, u64 *f_version,
                                 struct dir_context *ctx,
                                 bool persist)
{
        if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
                return ocfs2_dir_foreach_blk_id(inode, f_version, ctx);
        return ocfs2_dir_foreach_blk_el(inode, f_version, ctx, persist);
}

/*
 * This is intended to be called from inside other kernel functions,
 * so we fake some arguments.
 */
int ocfs2_dir_foreach(struct inode *inode, struct dir_context *ctx)
{
        u64 version = inode->i_version;
        ocfs2_dir_foreach_blk(inode, &version, ctx, true);
        return 0;
}

/*
 * ocfs2_readdir()
 *
 */
int ocfs2_readdir(struct file *file, struct dir_context *ctx)
{
        int error = 0;
        struct inode *inode = file_inode(file);
        int lock_level = 0;

        trace_ocfs2_readdir((unsigned long long)OCFS2_I(inode)->ip_blkno);

        error = ocfs2_inode_lock_atime(inode, file->f_path.mnt, &lock_level);
        if (lock_level && error >= 0) {
                /* We release EX lock which used to update atime
                 * and get PR lock again to reduce contention
                 * on commonly accessed directories. */
                ocfs2_inode_unlock(inode, 1);
                lock_level = 0;
                error = ocfs2_inode_lock(inode, NULL, 0);
        }
        if (error < 0) {
                if (error != -ENOENT)
                        mlog_errno(error);
                /* we haven't got any yet, so propagate the error. */
                goto bail_nolock;
        }

        error = ocfs2_dir_foreach_blk(inode, &file->f_version, ctx, false);

        ocfs2_inode_unlock(inode, lock_level);
        if (error)
                mlog_errno(error);

bail_nolock:

        return error;
}

/*
 * NOTE: this should always be called with parent dir i_mutex taken.
 */
int ocfs2_find_files_on_disk(const char *name,
                             int namelen,
                             u64 *blkno,
                             struct inode *inode,
                             struct ocfs2_dir_lookup_result *lookup)
{
        int status = -ENOENT;

        trace_ocfs2_find_files_on_disk(namelen, name, blkno,
                                (unsigned long long)OCFS2_I(inode)->ip_blkno);

        status = ocfs2_find_entry(name, namelen, inode, lookup);
        if (status)
                goto leave;

        *blkno = le64_to_cpu(lookup->dl_entry->inode);

        status = 0;
leave:

        return status;
}

/*
 * Convenience function for callers which just want the block number
 * mapped to a name and don't require the full dirent info, etc.
 */
int ocfs2_lookup_ino_from_name(struct inode *dir, const char *name,
                               int namelen, u64 *blkno)
{
        int ret;
        struct ocfs2_dir_lookup_result lookup = { NULL, };

        ret = ocfs2_find_files_on_disk(name, namelen, blkno, dir, &lookup);
        ocfs2_free_dir_lookup_result(&lookup);

        return ret;
}

/* Check for a name within a directory.
 *
 * Return 0 if the name does not exist
 * Return -EEXIST if the directory contains the name
 *
 * Callers should have i_mutex + a cluster lock on dir
 */
int ocfs2_check_dir_for_entry(struct inode *dir,
                              const char *name,
                              int namelen)
{
        int ret = 0;
        struct ocfs2_dir_lookup_result lookup = { NULL, };

        trace_ocfs2_check_dir_for_entry(
                (unsigned long long)OCFS2_I(dir)->ip_blkno, namelen, name);

        if (ocfs2_find_entry(name, namelen, dir, &lookup) == 0) {
                ret = -EEXIST;
                mlog_errno(ret);
        }

        ocfs2_free_dir_lookup_result(&lookup);

        return ret;
}

struct ocfs2_empty_dir_priv {
        struct dir_context ctx;
        unsigned seen_dot;
        unsigned seen_dot_dot;
        unsigned seen_other;
        unsigned dx_dir;
};
static int ocfs2_empty_dir_filldir(struct dir_context *ctx, const char *name,
                                   int name_len, loff_t pos, u64 ino,
                                   unsigned type)
{
        struct ocfs2_empty_dir_priv *p =
                container_of(ctx, struct ocfs2_empty_dir_priv, ctx);

        /*
         * Check the positions of "." and ".." records to be sure
         * they're in the correct place.
         *
         * Indexed directories don't need to proceed past the first
         * two entries, so we end the scan after seeing '..'. Despite
         * that, we allow the scan to proceed In the event that we
         * have a corrupted indexed directory (no dot or dot dot
         * entries). This allows us to double check for existing
         * entries which might not have been found in the index.
         */
        if (name_len == 1 && !strncmp(".", name, 1) && pos == 0) {
                p->seen_dot = 1;
                return 0;
        }

        if (name_len == 2 && !strncmp("..", name, 2) &&
            pos == OCFS2_DIR_REC_LEN(1)) {
                p->seen_dot_dot = 1;

                if (p->dx_dir && p->seen_dot)
                        return 1;

                return 0;
        }

        p->seen_other = 1;
        return 1;
}

static int ocfs2_empty_dir_dx(struct inode *inode,
                              struct ocfs2_empty_dir_priv *priv)
{
        int ret;
        struct buffer_head *di_bh = NULL;
        struct buffer_head *dx_root_bh = NULL;
        struct ocfs2_dinode *di;
        struct ocfs2_dx_root_block *dx_root;

        priv->dx_dir = 1;

        ret = ocfs2_read_inode_block(inode, &di_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
        di = (struct ocfs2_dinode *)di_bh->b_data;

        ret = ocfs2_read_dx_root(inode, di, &dx_root_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;

        if (le32_to_cpu(dx_root->dr_num_entries) != 2)
                priv->seen_other = 1;

out:
        brelse(di_bh);
        brelse(dx_root_bh);
        return ret;
}

/*
 * routine to check that the specified directory is empty (for rmdir)
 *
 * Returns 1 if dir is empty, zero otherwise.
 *
 * XXX: This is a performance problem for unindexed directories.
 */
int ocfs2_empty_dir(struct inode *inode)
{
        int ret;
        struct ocfs2_empty_dir_priv priv = {
                .ctx.actor = ocfs2_empty_dir_filldir,
        };

        if (ocfs2_dir_indexed(inode)) {
                ret = ocfs2_empty_dir_dx(inode, &priv);
                if (ret)
                        mlog_errno(ret);
                /*
                 * We still run ocfs2_dir_foreach to get the checks
                 * for "." and "..".
                 */
        }

        ret = ocfs2_dir_foreach(inode, &priv.ctx);
        if (ret)
                mlog_errno(ret);

        if (!priv.seen_dot || !priv.seen_dot_dot) {
                mlog(ML_ERROR, "bad directory (dir #%llu) - no `.' or `..'\n",
                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
                /*
                 * XXX: Is it really safe to allow an unlink to continue?
                 */
                return 1;
        }

        return !priv.seen_other;
}

/*
 * Fills "." and ".." dirents in a new directory block. Returns dirent for
 * "..", which might be used during creation of a directory with a trailing
 * header. It is otherwise safe to ignore the return code.
 */
static struct ocfs2_dir_entry *ocfs2_fill_initial_dirents(struct inode *inode,
                                                          struct inode *parent,
                                                          char *start,
                                                          unsigned int size)
{
        struct ocfs2_dir_entry *de = (struct ocfs2_dir_entry *)start;

        de->inode = cpu_to_le64(OCFS2_I(inode)->ip_blkno);
        de->name_len = 1;
        de->rec_len =
                cpu_to_le16(OCFS2_DIR_REC_LEN(de->name_len));
        strcpy(de->name, ".");
        ocfs2_set_de_type(de, S_IFDIR);

        de = (struct ocfs2_dir_entry *) ((char *)de + le16_to_cpu(de->rec_len));
        de->inode = cpu_to_le64(OCFS2_I(parent)->ip_blkno);
        de->rec_len = cpu_to_le16(size - OCFS2_DIR_REC_LEN(1));
        de->name_len = 2;
        strcpy(de->name, "..");
        ocfs2_set_de_type(de, S_IFDIR);

        return de;
}

/*
 * This works together with code in ocfs2_mknod_locked() which sets
 * the inline-data flag and initializes the inline-data section.
 */
static int ocfs2_fill_new_dir_id(struct ocfs2_super *osb,
                                 handle_t *handle,
                                 struct inode *parent,
                                 struct inode *inode,
                                 struct buffer_head *di_bh)
{
        int ret;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
        struct ocfs2_inline_data *data = &di->id2.i_data;
        unsigned int size = le16_to_cpu(data->id_count);

        ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        ocfs2_fill_initial_dirents(inode, parent, data->id_data, size);
        ocfs2_journal_dirty(handle, di_bh);

        i_size_write(inode, size);
        set_nlink(inode, 2);
        inode->i_blocks = ocfs2_inode_sector_count(inode);

        ret = ocfs2_mark_inode_dirty(handle, inode, di_bh);
        if (ret < 0)
                mlog_errno(ret);

out:
        return ret;
}

static int ocfs2_fill_new_dir_el(struct ocfs2_super *osb,
                                 handle_t *handle,
                                 struct inode *parent,
                                 struct inode *inode,
                                 struct buffer_head *fe_bh,
                                 struct ocfs2_alloc_context *data_ac,
                                 struct buffer_head **ret_new_bh)
{
        int status;
        unsigned int size = osb->sb->s_blocksize;
        struct buffer_head *new_bh = NULL;
        struct ocfs2_dir_entry *de;

        if (ocfs2_new_dir_wants_trailer(inode))
                size = ocfs2_dir_trailer_blk_off(parent->i_sb);

        status = ocfs2_do_extend_dir(osb->sb, handle, inode, fe_bh,
                                     data_ac, NULL, &new_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        ocfs2_set_new_buffer_uptodate(INODE_CACHE(inode), new_bh);

        status = ocfs2_journal_access_db(handle, INODE_CACHE(inode), new_bh,
                                         OCFS2_JOURNAL_ACCESS_CREATE);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }
        memset(new_bh->b_data, 0, osb->sb->s_blocksize);

        de = ocfs2_fill_initial_dirents(inode, parent, new_bh->b_data, size);
        if (ocfs2_new_dir_wants_trailer(inode)) {
                int size = le16_to_cpu(de->rec_len);

                /*
                 * Figure out the size of the hole left over after
                 * insertion of '.' and '..'. The trailer wants this
                 * information.
                 */
                size -= OCFS2_DIR_REC_LEN(2);
                size -= sizeof(struct ocfs2_dir_block_trailer);

                ocfs2_init_dir_trailer(inode, new_bh, size);
        }

        ocfs2_journal_dirty(handle, new_bh);

        i_size_write(inode, inode->i_sb->s_blocksize);
        set_nlink(inode, 2);
        inode->i_blocks = ocfs2_inode_sector_count(inode);
        status = ocfs2_mark_inode_dirty(handle, inode, fe_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        status = 0;
        if (ret_new_bh) {
                *ret_new_bh = new_bh;
                new_bh = NULL;
        }
bail:
        brelse(new_bh);

        return status;
}

static int ocfs2_dx_dir_attach_index(struct ocfs2_super *osb,
                                     handle_t *handle, struct inode *dir,
                                     struct buffer_head *di_bh,
                                     struct buffer_head *dirdata_bh,
                                     struct ocfs2_alloc_context *meta_ac,
                                     int dx_inline, u32 num_entries,
                                     struct buffer_head **ret_dx_root_bh)
{
        int ret;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *) di_bh->b_data;
        u16 dr_suballoc_bit;
        u64 suballoc_loc, dr_blkno;
        unsigned int num_bits;
        struct buffer_head *dx_root_bh = NULL;
        struct ocfs2_dx_root_block *dx_root;
        struct ocfs2_dir_block_trailer *trailer =
                ocfs2_trailer_from_bh(dirdata_bh, dir->i_sb);

        ret = ocfs2_claim_metadata(handle, meta_ac, 1, &suballoc_loc,
                                   &dr_suballoc_bit, &num_bits, &dr_blkno);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        trace_ocfs2_dx_dir_attach_index(
                                (unsigned long long)OCFS2_I(dir)->ip_blkno,
                                (unsigned long long)dr_blkno);

        dx_root_bh = sb_getblk(osb->sb, dr_blkno);
        if (dx_root_bh == NULL) {
                ret = -ENOMEM;
                goto out;
        }
        ocfs2_set_new_buffer_uptodate(INODE_CACHE(dir), dx_root_bh);

        ret = ocfs2_journal_access_dr(handle, INODE_CACHE(dir), dx_root_bh,
                                      OCFS2_JOURNAL_ACCESS_CREATE);
        if (ret < 0) {
                mlog_errno(ret);
                goto out;
        }

        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;
        memset(dx_root, 0, osb->sb->s_blocksize);
        strcpy(dx_root->dr_signature, OCFS2_DX_ROOT_SIGNATURE);
        dx_root->dr_suballoc_slot = cpu_to_le16(meta_ac->ac_alloc_slot);
        dx_root->dr_suballoc_loc = cpu_to_le64(suballoc_loc);
        dx_root->dr_suballoc_bit = cpu_to_le16(dr_suballoc_bit);
        dx_root->dr_fs_generation = cpu_to_le32(osb->fs_generation);
        dx_root->dr_blkno = cpu_to_le64(dr_blkno);
        dx_root->dr_dir_blkno = cpu_to_le64(OCFS2_I(dir)->ip_blkno);
        dx_root->dr_num_entries = cpu_to_le32(num_entries);
        if (le16_to_cpu(trailer->db_free_rec_len))
                dx_root->dr_free_blk = cpu_to_le64(dirdata_bh->b_blocknr);
        else
                dx_root->dr_free_blk = cpu_to_le64(0);

        if (dx_inline) {
                dx_root->dr_flags |= OCFS2_DX_FLAG_INLINE;
                dx_root->dr_entries.de_count =
                        cpu_to_le16(ocfs2_dx_entries_per_root(osb->sb));
        } else {
                dx_root->dr_list.l_count =
                        cpu_to_le16(ocfs2_extent_recs_per_dx_root(osb->sb));
        }
        ocfs2_journal_dirty(handle, dx_root_bh);

        ret = ocfs2_journal_access_di(handle, INODE_CACHE(dir), di_bh,
                                      OCFS2_JOURNAL_ACCESS_CREATE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        di->i_dx_root = cpu_to_le64(dr_blkno);

        spin_lock(&OCFS2_I(dir)->ip_lock);
        OCFS2_I(dir)->ip_dyn_features |= OCFS2_INDEXED_DIR_FL;
        di->i_dyn_features = cpu_to_le16(OCFS2_I(dir)->ip_dyn_features);
        spin_unlock(&OCFS2_I(dir)->ip_lock);

        ocfs2_journal_dirty(handle, di_bh);

        *ret_dx_root_bh = dx_root_bh;
        dx_root_bh = NULL;

out:
        brelse(dx_root_bh);
        return ret;
}

static int ocfs2_dx_dir_format_cluster(struct ocfs2_super *osb,
                                       handle_t *handle, struct inode *dir,
                                       struct buffer_head **dx_leaves,
                                       int num_dx_leaves, u64 start_blk)
{
        int ret, i;
        struct ocfs2_dx_leaf *dx_leaf;
        struct buffer_head *bh;

        for (i = 0; i < num_dx_leaves; i++) {
                bh = sb_getblk(osb->sb, start_blk + i);
                if (bh == NULL) {
                        ret = -ENOMEM;
                        goto out;
                }
                dx_leaves[i] = bh;

                ocfs2_set_new_buffer_uptodate(INODE_CACHE(dir), bh);

                ret = ocfs2_journal_access_dl(handle, INODE_CACHE(dir), bh,
                                              OCFS2_JOURNAL_ACCESS_CREATE);
                if (ret < 0) {
                        mlog_errno(ret);
                        goto out;
                }

                dx_leaf = (struct ocfs2_dx_leaf *) bh->b_data;

                memset(dx_leaf, 0, osb->sb->s_blocksize);
                strcpy(dx_leaf->dl_signature, OCFS2_DX_LEAF_SIGNATURE);
                dx_leaf->dl_fs_generation = cpu_to_le32(osb->fs_generation);
                dx_leaf->dl_blkno = cpu_to_le64(bh->b_blocknr);
                dx_leaf->dl_list.de_count =
                        cpu_to_le16(ocfs2_dx_entries_per_leaf(osb->sb));

                trace_ocfs2_dx_dir_format_cluster(
                                (unsigned long long)OCFS2_I(dir)->ip_blkno,
                                (unsigned long long)bh->b_blocknr,
                                le16_to_cpu(dx_leaf->dl_list.de_count));

                ocfs2_journal_dirty(handle, bh);
        }

        ret = 0;
out:
        return ret;
}

/*
 * Allocates and formats a new cluster for use in an indexed dir
 * leaf. This version will not do the extent insert, so that it can be
 * used by operations which need careful ordering.
 */
static int __ocfs2_dx_dir_new_cluster(struct inode *dir,
                                      u32 cpos, handle_t *handle,
                                      struct ocfs2_alloc_context *data_ac,
                                      struct buffer_head **dx_leaves,
                                      int num_dx_leaves, u64 *ret_phys_blkno)
{
        int ret;
        u32 phys, num;
        u64 phys_blkno;
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);

        /*
         * XXX: For create, this should claim cluster for the index
         * *before* the unindexed insert so that we have a better
         * chance of contiguousness as the directory grows in number
         * of entries.
         */
        ret = __ocfs2_claim_clusters(handle, data_ac, 1, 1, &phys, &num);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        /*
         * Format the new cluster first. That way, we're inserting
         * valid data.
         */
        phys_blkno = ocfs2_clusters_to_blocks(osb->sb, phys);
        ret = ocfs2_dx_dir_format_cluster(osb, handle, dir, dx_leaves,
                                          num_dx_leaves, phys_blkno);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        *ret_phys_blkno = phys_blkno;
out:
        return ret;
}

static int ocfs2_dx_dir_new_cluster(struct inode *dir,
                                    struct ocfs2_extent_tree *et,
                                    u32 cpos, handle_t *handle,
                                    struct ocfs2_alloc_context *data_ac,
                                    struct ocfs2_alloc_context *meta_ac,
                                    struct buffer_head **dx_leaves,
                                    int num_dx_leaves)
{
        int ret;
        u64 phys_blkno;

        ret = __ocfs2_dx_dir_new_cluster(dir, cpos, handle, data_ac, dx_leaves,
                                         num_dx_leaves, &phys_blkno);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        ret = ocfs2_insert_extent(handle, et, cpos, phys_blkno, 1, 0,
                                  meta_ac);
        if (ret)
                mlog_errno(ret);
out:
        return ret;
}

static struct buffer_head **ocfs2_dx_dir_kmalloc_leaves(struct super_block *sb,
                                                        int *ret_num_leaves)
{
        int num_dx_leaves = ocfs2_clusters_to_blocks(sb, 1);
        struct buffer_head **dx_leaves;

        dx_leaves = kcalloc(num_dx_leaves, sizeof(struct buffer_head *),
                            GFP_NOFS);
        if (dx_leaves && ret_num_leaves)
                *ret_num_leaves = num_dx_leaves;

        return dx_leaves;
}

static int ocfs2_fill_new_dir_dx(struct ocfs2_super *osb,
                                 handle_t *handle,
                                 struct inode *parent,
                                 struct inode *inode,
                                 struct buffer_head *di_bh,
                                 struct ocfs2_alloc_context *data_ac,
                                 struct ocfs2_alloc_context *meta_ac)
{
        int ret;
        struct buffer_head *leaf_bh = NULL;
        struct buffer_head *dx_root_bh = NULL;
        struct ocfs2_dx_hinfo hinfo;
        struct ocfs2_dx_root_block *dx_root;
        struct ocfs2_dx_entry_list *entry_list;

        /*
         * Our strategy is to create the directory as though it were
         * unindexed, then add the index block. This works with very
         * little complication since the state of a new directory is a
         * very well known quantity.
         *
         * Essentially, we have two dirents ("." and ".."), in the 1st
         * block which need indexing. These are easily inserted into
         * the index block.
         */

        ret = ocfs2_fill_new_dir_el(osb, handle, parent, inode, di_bh,
                                    data_ac, &leaf_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        ret = ocfs2_dx_dir_attach_index(osb, handle, inode, di_bh, leaf_bh,
                                        meta_ac, 1, 2, &dx_root_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;
        entry_list = &dx_root->dr_entries;

        /* Buffer has been journaled for us by ocfs2_dx_dir_attach_index */
        ocfs2_dx_dir_name_hash(inode, ".", 1, &hinfo);
        ocfs2_dx_entry_list_insert(entry_list, &hinfo, leaf_bh->b_blocknr);

        ocfs2_dx_dir_name_hash(inode, "..", 2, &hinfo);
        ocfs2_dx_entry_list_insert(entry_list, &hinfo, leaf_bh->b_blocknr);

out:
        brelse(dx_root_bh);
        brelse(leaf_bh);
        return ret;
}

int ocfs2_fill_new_dir(struct ocfs2_super *osb,
                       handle_t *handle,
                       struct inode *parent,
                       struct inode *inode,
                       struct buffer_head *fe_bh,
                       struct ocfs2_alloc_context *data_ac,
                       struct ocfs2_alloc_context *meta_ac)

{
        BUG_ON(!ocfs2_supports_inline_data(osb) && data_ac == NULL);

        if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
                return ocfs2_fill_new_dir_id(osb, handle, parent, inode, fe_bh);

        if (ocfs2_supports_indexed_dirs(osb))
                return ocfs2_fill_new_dir_dx(osb, handle, parent, inode, fe_bh,
                                             data_ac, meta_ac);

        return ocfs2_fill_new_dir_el(osb, handle, parent, inode, fe_bh,
                                     data_ac, NULL);
}

static int ocfs2_dx_dir_index_block(struct inode *dir,
                                    handle_t *handle,
                                    struct buffer_head **dx_leaves,
                                    int num_dx_leaves,
                                    u32 *num_dx_entries,
                                    struct buffer_head *dirent_bh)
{
        int ret = 0, namelen, i;
        char *de_buf, *limit;
        struct ocfs2_dir_entry *de;
        struct buffer_head *dx_leaf_bh;
        struct ocfs2_dx_hinfo hinfo;
        u64 dirent_blk = dirent_bh->b_blocknr;

        de_buf = dirent_bh->b_data;
        limit = de_buf + dir->i_sb->s_blocksize;

        while (de_buf < limit) {
                de = (struct ocfs2_dir_entry *)de_buf;

                namelen = de->name_len;
                if (!namelen || !de->inode)
                        goto inc;

                ocfs2_dx_dir_name_hash(dir, de->name, namelen, &hinfo);

                i = ocfs2_dx_dir_hash_idx(OCFS2_SB(dir->i_sb), &hinfo);
                dx_leaf_bh = dx_leaves[i];

                ret = __ocfs2_dx_dir_leaf_insert(dir, handle, &hinfo,
                                                 dirent_blk, dx_leaf_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                *num_dx_entries = *num_dx_entries + 1;

inc:
                de_buf += le16_to_cpu(de->rec_len);
        }

out:
        return ret;
}

/*
 * XXX: This expects dx_root_bh to already be part of the transaction.
 */
static void ocfs2_dx_dir_index_root_block(struct inode *dir,
                                         struct buffer_head *dx_root_bh,
                                         struct buffer_head *dirent_bh)
{
        char *de_buf, *limit;
        struct ocfs2_dx_root_block *dx_root;
        struct ocfs2_dir_entry *de;
        struct ocfs2_dx_hinfo hinfo;
        u64 dirent_blk = dirent_bh->b_blocknr;

        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;

        de_buf = dirent_bh->b_data;
        limit = de_buf + dir->i_sb->s_blocksize;

        while (de_buf < limit) {
                de = (struct ocfs2_dir_entry *)de_buf;

                if (!de->name_len || !de->inode)
                        goto inc;

                ocfs2_dx_dir_name_hash(dir, de->name, de->name_len, &hinfo);

                trace_ocfs2_dx_dir_index_root_block(
                                (unsigned long long)dir->i_ino,
                                hinfo.major_hash, hinfo.minor_hash,
                                de->name_len, de->name,
                                le16_to_cpu(dx_root->dr_entries.de_num_used));

                ocfs2_dx_entry_list_insert(&dx_root->dr_entries, &hinfo,
                                           dirent_blk);

                le32_add_cpu(&dx_root->dr_num_entries, 1);
inc:
                de_buf += le16_to_cpu(de->rec_len);
        }
}

/*
 * Count the number of inline directory entries in di_bh and compare
 * them against the number of entries we can hold in an inline dx root
 * block.
 */
static int ocfs2_new_dx_should_be_inline(struct inode *dir,
                                         struct buffer_head *di_bh)
{
        int dirent_count = 0;
        char *de_buf, *limit;
        struct ocfs2_dir_entry *de;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;

        de_buf = di->id2.i_data.id_data;
        limit = de_buf + i_size_read(dir);

        while (de_buf < limit) {
                de = (struct ocfs2_dir_entry *)de_buf;

                if (de->name_len && de->inode)
                        dirent_count++;

                de_buf += le16_to_cpu(de->rec_len);
        }

        /* We are careful to leave room for one extra record. */
        return dirent_count < ocfs2_dx_entries_per_root(dir->i_sb);
}

/*
 * Expand rec_len of the rightmost dirent in a directory block so that it
 * contains the end of our valid space for dirents. We do this during
 * expansion from an inline directory to one with extents. The first dir block
 * in that case is taken from the inline data portion of the inode block.
 *
 * This will also return the largest amount of contiguous space for a dirent
 * in the block. That value is *not* necessarily the last dirent, even after
 * expansion. The directory indexing code wants this value for free space
 * accounting. We do this here since we're already walking the entire dir
 * block.
 *
 * We add the dir trailer if this filesystem wants it.
 */
static unsigned int ocfs2_expand_last_dirent(char *start, unsigned int old_size,
                                             struct inode *dir)
{
        struct super_block *sb = dir->i_sb;
        struct ocfs2_dir_entry *de;
        struct ocfs2_dir_entry *prev_de;
        char *de_buf, *limit;
        unsigned int new_size = sb->s_blocksize;
        unsigned int bytes, this_hole;
        unsigned int largest_hole = 0;

        if (ocfs2_new_dir_wants_trailer(dir))
                new_size = ocfs2_dir_trailer_blk_off(sb);

        bytes = new_size - old_size;

        limit = start + old_size;
        de_buf = start;
        de = (struct ocfs2_dir_entry *)de_buf;
        do {
                this_hole = ocfs2_figure_dirent_hole(de);
                if (this_hole > largest_hole)
                        largest_hole = this_hole;

                prev_de = de;
                de_buf += le16_to_cpu(de->rec_len);
                de = (struct ocfs2_dir_entry *)de_buf;
        } while (de_buf < limit);

        le16_add_cpu(&prev_de->rec_len, bytes);

        /* We need to double check this after modification of the final
         * dirent. */
        this_hole = ocfs2_figure_dirent_hole(prev_de);
        if (this_hole > largest_hole)
                largest_hole = this_hole;

        if (largest_hole >= OCFS2_DIR_MIN_REC_LEN)
                return largest_hole;
        return 0;
}

/*
 * We allocate enough clusters to fulfill "blocks_wanted", but set
 * i_size to exactly one block. Ocfs2_extend_dir() will handle the
 * rest automatically for us.
 *
 * *first_block_bh is a pointer to the 1st data block allocated to the
 *  directory.
 */
static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
                                   unsigned int blocks_wanted,
                                   struct ocfs2_dir_lookup_result *lookup,
                                   struct buffer_head **first_block_bh)
{
        u32 alloc, dx_alloc, bit_off, len, num_dx_entries = 0;
        struct super_block *sb = dir->i_sb;
        int ret, i, num_dx_leaves = 0, dx_inline = 0,
                credits = ocfs2_inline_to_extents_credits(sb);
        u64 dx_insert_blkno, blkno,
                bytes = blocks_wanted << sb->s_blocksize_bits;
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
        struct ocfs2_inode_info *oi = OCFS2_I(dir);
        struct ocfs2_alloc_context *data_ac = NULL;
        struct ocfs2_alloc_context *meta_ac = NULL;
        struct buffer_head *dirdata_bh = NULL;
        struct buffer_head *dx_root_bh = NULL;
        struct buffer_head **dx_leaves = NULL;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
        handle_t *handle;
        struct ocfs2_extent_tree et;
        struct ocfs2_extent_tree dx_et;
        int did_quota = 0, bytes_allocated = 0;

        ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(dir), di_bh);

        alloc = ocfs2_clusters_for_bytes(sb, bytes);
        dx_alloc = 0;

        down_write(&oi->ip_alloc_sem);

        if (ocfs2_supports_indexed_dirs(osb)) {
                credits += ocfs2_add_dir_index_credits(sb);

                dx_inline = ocfs2_new_dx_should_be_inline(dir, di_bh);
                if (!dx_inline) {
                        /* Add one more cluster for an index leaf */
                        dx_alloc++;
                        dx_leaves = ocfs2_dx_dir_kmalloc_leaves(sb,
                                                                &num_dx_leaves);
                        if (!dx_leaves) {
                                ret = -ENOMEM;
                                mlog_errno(ret);
                                goto out;
                        }
                }

                /* This gets us the dx_root */
                ret = ocfs2_reserve_new_metadata_blocks(osb, 1, &meta_ac);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }
        }

        /*
         * We should never need more than 2 clusters for the unindexed
         * tree - maximum dirent size is far less than one block. In
         * fact, the only time we'd need more than one cluster is if
         * blocksize == clustersize and the dirent won't fit in the
         * extra space that the expansion to a single block gives. As
         * of today, that only happens on 4k/4k file systems.
         */
        BUG_ON(alloc > 2);

        ret = ocfs2_reserve_clusters(osb, alloc + dx_alloc, &data_ac);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        /*
         * Prepare for worst case allocation scenario of two separate
         * extents in the unindexed tree.
         */
        if (alloc == 2)
                credits += OCFS2_SUBALLOC_ALLOC;

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

        ret = dquot_alloc_space_nodirty(dir,
                ocfs2_clusters_to_bytes(osb->sb, alloc + dx_alloc));
        if (ret)
                goto out_commit;
        did_quota = 1;

        if (ocfs2_supports_indexed_dirs(osb) && !dx_inline) {
                /*
                 * Allocate our index cluster first, to maximize the
                 * possibility that unindexed leaves grow
                 * contiguously.
                 */
                ret = __ocfs2_dx_dir_new_cluster(dir, 0, handle, data_ac,
                                                 dx_leaves, num_dx_leaves,
                                                 &dx_insert_blkno);
                if (ret) {
                        mlog_errno(ret);
                        goto out_commit;
                }
                bytes_allocated += ocfs2_clusters_to_bytes(dir->i_sb, 1);
        }

        /*
         * Try to claim as many clusters as the bitmap can give though
         * if we only get one now, that's enough to continue. The rest
         * will be claimed after the conversion to extents.
         */
        if (ocfs2_dir_resv_allowed(osb))
                data_ac->ac_resv = &oi->ip_la_data_resv;
        ret = ocfs2_claim_clusters(handle, data_ac, 1, &bit_off, &len);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }
        bytes_allocated += ocfs2_clusters_to_bytes(dir->i_sb, 1);

        /*
         * Operations are carefully ordered so that we set up the new
         * data block first. The conversion from inline data to
         * extents follows.
         */
        blkno = ocfs2_clusters_to_blocks(dir->i_sb, bit_off);
        dirdata_bh = sb_getblk(sb, blkno);
        if (!dirdata_bh) {
                ret = -ENOMEM;
                mlog_errno(ret);
                goto out_commit;
        }

        ocfs2_set_new_buffer_uptodate(INODE_CACHE(dir), dirdata_bh);

        ret = ocfs2_journal_access_db(handle, INODE_CACHE(dir), dirdata_bh,
                                      OCFS2_JOURNAL_ACCESS_CREATE);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        memcpy(dirdata_bh->b_data, di->id2.i_data.id_data, i_size_read(dir));
        memset(dirdata_bh->b_data + i_size_read(dir), 0,
               sb->s_blocksize - i_size_read(dir));
        i = ocfs2_expand_last_dirent(dirdata_bh->b_data, i_size_read(dir), dir);
        if (ocfs2_new_dir_wants_trailer(dir)) {
                /*
                 * Prepare the dir trailer up front. It will otherwise look
                 * like a valid dirent. Even if inserting the index fails
                 * (unlikely), then all we'll have done is given first dir
                 * block a small amount of fragmentation.
                 */
                ocfs2_init_dir_trailer(dir, dirdata_bh, i);
        }

        ocfs2_update_inode_fsync_trans(handle, dir, 1);
        ocfs2_journal_dirty(handle, dirdata_bh);

        if (ocfs2_supports_indexed_dirs(osb) && !dx_inline) {
                /*
                 * Dx dirs with an external cluster need to do this up
                 * front. Inline dx root's get handled later, after
                 * we've allocated our root block. We get passed back
                 * a total number of items so that dr_num_entries can
                 * be correctly set once the dx_root has been
                 * allocated.
                 */
                ret = ocfs2_dx_dir_index_block(dir, handle, dx_leaves,
                                               num_dx_leaves, &num_dx_entries,
                                               dirdata_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto out_commit;
                }
        }

        /*
         * Set extent, i_size, etc on the directory. After this, the
         * inode should contain the same exact dirents as before and
         * be fully accessible from system calls.
         *
         * We let the later dirent insert modify c/mtime - to the user
         * the data hasn't changed.
         */
        ret = ocfs2_journal_access_di(handle, INODE_CACHE(dir), di_bh,
                                      OCFS2_JOURNAL_ACCESS_CREATE);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        spin_lock(&oi->ip_lock);
        oi->ip_dyn_features &= ~OCFS2_INLINE_DATA_FL;
        di->i_dyn_features = cpu_to_le16(oi->ip_dyn_features);
        spin_unlock(&oi->ip_lock);

        ocfs2_dinode_new_extent_list(dir, di);

        i_size_write(dir, sb->s_blocksize);
        dir->i_mtime = dir->i_ctime = CURRENT_TIME;

        di->i_size = cpu_to_le64(sb->s_blocksize);
        di->i_ctime = di->i_mtime = cpu_to_le64(dir->i_ctime.tv_sec);
        di->i_ctime_nsec = di->i_mtime_nsec = cpu_to_le32(dir->i_ctime.tv_nsec);
        ocfs2_update_inode_fsync_trans(handle, dir, 1);

        /*
         * This should never fail as our extent list is empty and all
         * related blocks have been journaled already.
         */
        ret = ocfs2_insert_extent(handle, &et, 0, blkno, len,
                                  0, NULL);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        /*
         * Set i_blocks after the extent insert for the most up to
         * date ip_clusters value.
         */
        dir->i_blocks = ocfs2_inode_sector_count(dir);

        ocfs2_journal_dirty(handle, di_bh);

        if (ocfs2_supports_indexed_dirs(osb)) {
                ret = ocfs2_dx_dir_attach_index(osb, handle, dir, di_bh,
                                                dirdata_bh, meta_ac, dx_inline,
                                                num_dx_entries, &dx_root_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto out_commit;
                }

                if (dx_inline) {
                        ocfs2_dx_dir_index_root_block(dir, dx_root_bh,
                                                      dirdata_bh);
                } else {
                        ocfs2_init_dx_root_extent_tree(&dx_et,
                                                       INODE_CACHE(dir),
                                                       dx_root_bh);
                        ret = ocfs2_insert_extent(handle, &dx_et, 0,
                                                  dx_insert_blkno, 1, 0, NULL);
                        if (ret)
                                mlog_errno(ret);
                }
        }

        /*
         * We asked for two clusters, but only got one in the 1st
         * pass. Claim the 2nd cluster as a separate extent.
         */
        if (alloc > len) {
                ret = ocfs2_claim_clusters(handle, data_ac, 1, &bit_off,
                                           &len);
                if (ret) {
                        mlog_errno(ret);
                        goto out_commit;
                }
                blkno = ocfs2_clusters_to_blocks(dir->i_sb, bit_off);

                ret = ocfs2_insert_extent(handle, &et, 1,
                                          blkno, len, 0, NULL);
                if (ret) {
                        mlog_errno(ret);
                        goto out_commit;
                }
                bytes_allocated += ocfs2_clusters_to_bytes(dir->i_sb, 1);
        }

        *first_block_bh = dirdata_bh;
        dirdata_bh = NULL;
        if (ocfs2_supports_indexed_dirs(osb)) {
                unsigned int off;

                if (!dx_inline) {
                        /*
                         * We need to return the correct block within the
                         * cluster which should hold our entry.
                         */
                        off = ocfs2_dx_dir_hash_idx(OCFS2_SB(dir->i_sb),
                                                    &lookup->dl_hinfo);
                        get_bh(dx_leaves[off]);
                        lookup->dl_dx_leaf_bh = dx_leaves[off];
                }
                lookup->dl_dx_root_bh = dx_root_bh;
                dx_root_bh = NULL;
        }

out_commit:
        if (ret < 0 && did_quota)
                dquot_free_space_nodirty(dir, bytes_allocated);

        ocfs2_commit_trans(osb, handle);

out:
        up_write(&oi->ip_alloc_sem);
        if (data_ac)
                ocfs2_free_alloc_context(data_ac);
        if (meta_ac)
                ocfs2_free_alloc_context(meta_ac);

        if (dx_leaves) {
                for (i = 0; i < num_dx_leaves; i++)
                        brelse(dx_leaves[i]);
                kfree(dx_leaves);
        }

        brelse(dirdata_bh);
        brelse(dx_root_bh);

        return ret;
}

/* returns a bh of the 1st new block in the allocation. */
static int ocfs2_do_extend_dir(struct super_block *sb,
                               handle_t *handle,
                               struct inode *dir,
                               struct buffer_head *parent_fe_bh,
                               struct ocfs2_alloc_context *data_ac,
                               struct ocfs2_alloc_context *meta_ac,
                               struct buffer_head **new_bh)
{
        int status;
        int extend, did_quota = 0;
        u64 p_blkno, v_blkno;

        spin_lock(&OCFS2_I(dir)->ip_lock);
        extend = (i_size_read(dir) == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters));
        spin_unlock(&OCFS2_I(dir)->ip_lock);

        if (extend) {
                u32 offset = OCFS2_I(dir)->ip_clusters;

                status = dquot_alloc_space_nodirty(dir,
                                        ocfs2_clusters_to_bytes(sb, 1));
                if (status)
                        goto bail;
                did_quota = 1;

                status = ocfs2_add_inode_data(OCFS2_SB(sb), dir, &offset,
                                              1, 0, parent_fe_bh, handle,
                                              data_ac, meta_ac, NULL);
                BUG_ON(status == -EAGAIN);
                if (status < 0) {
                        mlog_errno(status);
                        goto bail;
                }
        }

        v_blkno = ocfs2_blocks_for_bytes(sb, i_size_read(dir));
        status = ocfs2_extent_map_get_blocks(dir, v_blkno, &p_blkno, NULL, NULL);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        *new_bh = sb_getblk(sb, p_blkno);
        if (!*new_bh) {
                status = -ENOMEM;
                mlog_errno(status);
                goto bail;
        }
        status = 0;
bail:
        if (did_quota && status < 0)
                dquot_free_space_nodirty(dir, ocfs2_clusters_to_bytes(sb, 1));
        return status;
}

/*
 * Assumes you already have a cluster lock on the directory.
 *
 * 'blocks_wanted' is only used if we have an inline directory which
 * is to be turned into an extent based one. The size of the dirent to
 * insert might be larger than the space gained by growing to just one
 * block, so we may have to grow the inode by two blocks in that case.
 *
 * If the directory is already indexed, dx_root_bh must be provided.
 */
static int ocfs2_extend_dir(struct ocfs2_super *osb,
                            struct inode *dir,
                            struct buffer_head *parent_fe_bh,
                            unsigned int blocks_wanted,
                            struct ocfs2_dir_lookup_result *lookup,
                            struct buffer_head **new_de_bh)
{
        int status = 0;
        int credits, num_free_extents, drop_alloc_sem = 0;
        loff_t dir_i_size;
        struct ocfs2_dinode *fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
        struct ocfs2_extent_list *el = &fe->id2.i_list;
        struct ocfs2_alloc_context *data_ac = NULL;
        struct ocfs2_alloc_context *meta_ac = NULL;
        handle_t *handle = NULL;
        struct buffer_head *new_bh = NULL;
        struct ocfs2_dir_entry * de;
        struct super_block *sb = osb->sb;
        struct ocfs2_extent_tree et;
        struct buffer_head *dx_root_bh = lookup->dl_dx_root_bh;

        if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
                /*
                 * This would be a code error as an inline directory should
                 * never have an index root.
                 */
                BUG_ON(dx_root_bh);

                status = ocfs2_expand_inline_dir(dir, parent_fe_bh,
                                                 blocks_wanted, lookup,
                                                 &new_bh);
                if (status) {
                        mlog_errno(status);
                        goto bail;
                }

                /* Expansion from inline to an indexed directory will
                 * have given us this. */
                dx_root_bh = lookup->dl_dx_root_bh;

                if (blocks_wanted == 1) {
                        /*
                         * If the new dirent will fit inside the space
                         * created by pushing out to one block, then
                         * we can complete the operation
                         * here. Otherwise we have to expand i_size
                         * and format the 2nd block below.
                         */
                        BUG_ON(new_bh == NULL);
                        goto bail_bh;
                }

                /*
                 * Get rid of 'new_bh' - we want to format the 2nd
                 * data block and return that instead.
                 */
                brelse(new_bh);
                new_bh = NULL;

                down_write(&OCFS2_I(dir)->ip_alloc_sem);
                drop_alloc_sem = 1;
                dir_i_size = i_size_read(dir);
                credits = OCFS2_SIMPLE_DIR_EXTEND_CREDITS;
                goto do_extend;
        }

        down_write(&OCFS2_I(dir)->ip_alloc_sem);
        drop_alloc_sem = 1;
        dir_i_size = i_size_read(dir);
        trace_ocfs2_extend_dir((unsigned long long)OCFS2_I(dir)->ip_blkno,
                               dir_i_size);

        /* dir->i_size is always block aligned. */
        spin_lock(&OCFS2_I(dir)->ip_lock);
        if (dir_i_size == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters)) {
                spin_unlock(&OCFS2_I(dir)->ip_lock);
                ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(dir),
                                              parent_fe_bh);
                num_free_extents = ocfs2_num_free_extents(osb, &et);
                if (num_free_extents < 0) {
                        status = num_free_extents;
                        mlog_errno(status);
                        goto bail;
                }

                if (!num_free_extents) {
                        status = ocfs2_reserve_new_metadata(osb, el, &meta_ac);
                        if (status < 0) {
                                if (status != -ENOSPC)
                                        mlog_errno(status);
                                goto bail;
                        }
                }

                status = ocfs2_reserve_clusters(osb, 1, &data_ac);
                if (status < 0) {
                        if (status != -ENOSPC)
                                mlog_errno(status);
                        goto bail;
                }

                if (ocfs2_dir_resv_allowed(osb))
                        data_ac->ac_resv = &OCFS2_I(dir)->ip_la_data_resv;

                credits = ocfs2_calc_extend_credits(sb, el);
        } else {
                spin_unlock(&OCFS2_I(dir)->ip_lock);
                credits = OCFS2_SIMPLE_DIR_EXTEND_CREDITS;
        }

do_extend:
        if (ocfs2_dir_indexed(dir))
                credits++; /* For attaching the new dirent block to the
                            * dx_root */

        handle = ocfs2_start_trans(osb, credits);
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
                handle = NULL;
                mlog_errno(status);
                goto bail;
        }

        status = ocfs2_do_extend_dir(osb->sb, handle, dir, parent_fe_bh,
                                     data_ac, meta_ac, &new_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        ocfs2_set_new_buffer_uptodate(INODE_CACHE(dir), new_bh);

        status = ocfs2_journal_access_db(handle, INODE_CACHE(dir), new_bh,
                                         OCFS2_JOURNAL_ACCESS_CREATE);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }
        memset(new_bh->b_data, 0, sb->s_blocksize);

        de = (struct ocfs2_dir_entry *) new_bh->b_data;
        de->inode = 0;
        if (ocfs2_supports_dir_trailer(dir)) {
                de->rec_len = cpu_to_le16(ocfs2_dir_trailer_blk_off(sb));

                ocfs2_init_dir_trailer(dir, new_bh, le16_to_cpu(de->rec_len));

                if (ocfs2_dir_indexed(dir)) {
                        status = ocfs2_dx_dir_link_trailer(dir, handle,
                                                           dx_root_bh, new_bh);
                        if (status) {
                                mlog_errno(status);
                                goto bail;
                        }
                }
        } else {
                de->rec_len = cpu_to_le16(sb->s_blocksize);
        }
        ocfs2_update_inode_fsync_trans(handle, dir, 1);
        ocfs2_journal_dirty(handle, new_bh);

        dir_i_size += dir->i_sb->s_blocksize;
        i_size_write(dir, dir_i_size);
        dir->i_blocks = ocfs2_inode_sector_count(dir);
        status = ocfs2_mark_inode_dirty(handle, dir, parent_fe_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

bail_bh:
        *new_de_bh = new_bh;
        get_bh(*new_de_bh);
bail:
        if (handle)
                ocfs2_commit_trans(osb, handle);
        if (drop_alloc_sem)
                up_write(&OCFS2_I(dir)->ip_alloc_sem);

        if (data_ac)
                ocfs2_free_alloc_context(data_ac);
        if (meta_ac)
                ocfs2_free_alloc_context(meta_ac);

        brelse(new_bh);

        return status;
}

static int ocfs2_find_dir_space_id(struct inode *dir, struct buffer_head *di_bh,
                                   const char *name, int namelen,
                                   struct buffer_head **ret_de_bh,
                                   unsigned int *blocks_wanted)
{
        int ret;
        struct super_block *sb = dir->i_sb;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
        struct ocfs2_dir_entry *de, *last_de = NULL;
        char *de_buf, *limit;
        unsigned long offset = 0;
        unsigned int rec_len, new_rec_len, free_space = dir->i_sb->s_blocksize;

        /*
         * This calculates how many free bytes we'd have in block zero, should
         * this function force expansion to an extent tree.
         */
        if (ocfs2_new_dir_wants_trailer(dir))
                free_space = ocfs2_dir_trailer_blk_off(sb) - i_size_read(dir);
        else
                free_space = dir->i_sb->s_blocksize - i_size_read(dir);

        de_buf = di->id2.i_data.id_data;
        limit = de_buf + i_size_read(dir);
        rec_len = OCFS2_DIR_REC_LEN(namelen);

        while (de_buf < limit) {
                de = (struct ocfs2_dir_entry *)de_buf;

                if (!ocfs2_check_dir_entry(dir, de, di_bh, offset)) {
                        ret = -ENOENT;
                        goto out;
                }
                if (ocfs2_match(namelen, name, de)) {
                        ret = -EEXIST;
                        goto out;
                }
                /*
                 * No need to check for a trailing dirent record here as
                 * they're not used for inline dirs.
                 */

                if (ocfs2_dirent_would_fit(de, rec_len)) {
                        /* Ok, we found a spot. Return this bh and let
                         * the caller actually fill it in. */
                        *ret_de_bh = di_bh;
                        get_bh(*ret_de_bh);
                        ret = 0;
                        goto out;
                }

                last_de = de;
                de_buf += le16_to_cpu(de->rec_len);
                offset += le16_to_cpu(de->rec_len);
        }

        /*
         * We're going to require expansion of the directory - figure
         * out how many blocks we'll need so that a place for the
         * dirent can be found.
         */
        *blocks_wanted = 1;
        new_rec_len = le16_to_cpu(last_de->rec_len) + free_space;
        if (new_rec_len < (rec_len + OCFS2_DIR_REC_LEN(last_de->name_len)))
                *blocks_wanted = 2;

        ret = -ENOSPC;
out:
        return ret;
}

static int ocfs2_find_dir_space_el(struct inode *dir, const char *name,
                                   int namelen, struct buffer_head **ret_de_bh)
{
        unsigned long offset;
        struct buffer_head *bh = NULL;
        unsigned short rec_len;
        struct ocfs2_dir_entry *de;
        struct super_block *sb = dir->i_sb;
        int status;
        int blocksize = dir->i_sb->s_blocksize;

        status = ocfs2_read_dir_block(dir, 0, &bh, 0);
        if (status)
                goto bail;

        rec_len = OCFS2_DIR_REC_LEN(namelen);
        offset = 0;
        de = (struct ocfs2_dir_entry *) bh->b_data;
        while (1) {
                if ((char *)de >= sb->s_blocksize + bh->b_data) {
                        brelse(bh);
                        bh = NULL;

                        if (i_size_read(dir) <= offset) {
                                /*
                                 * Caller will have to expand this
                                 * directory.
                                 */
                                status = -ENOSPC;
                                goto bail;
                        }
                        status = ocfs2_read_dir_block(dir,
                                             offset >> sb->s_blocksize_bits,
                                             &bh, 0);
                        if (status)
                                goto bail;

                        /* move to next block */
                        de = (struct ocfs2_dir_entry *) bh->b_data;
                }
                if (!ocfs2_check_dir_entry(dir, de, bh, offset)) {
                        status = -ENOENT;
                        goto bail;
                }
                if (ocfs2_match(namelen, name, de)) {
                        status = -EEXIST;
                        goto bail;
                }

                if (ocfs2_skip_dir_trailer(dir, de, offset % blocksize,
                                           blocksize))
                        goto next;

                if (ocfs2_dirent_would_fit(de, rec_len)) {
                        /* Ok, we found a spot. Return this bh and let
                         * the caller actually fill it in. */
                        *ret_de_bh = bh;
                        get_bh(*ret_de_bh);
                        status = 0;
                        goto bail;
                }
next:
                offset += le16_to_cpu(de->rec_len);
                de = (struct ocfs2_dir_entry *)((char *) de + le16_to_cpu(de->rec_len));
        }

bail:
        brelse(bh);
        if (status)
                mlog_errno(status);

        return status;
}

static int dx_leaf_sort_cmp(const void *a, const void *b)
{
        const struct ocfs2_dx_entry *entry1 = a;
        const struct ocfs2_dx_entry *entry2 = b;
        u32 major_hash1 = le32_to_cpu(entry1->dx_major_hash);
        u32 major_hash2 = le32_to_cpu(entry2->dx_major_hash);
        u32 minor_hash1 = le32_to_cpu(entry1->dx_minor_hash);
        u32 minor_hash2 = le32_to_cpu(entry2->dx_minor_hash);

        if (major_hash1 > major_hash2)
                return 1;
        if (major_hash1 < major_hash2)
                return -1;

        /*
         * It is not strictly necessary to sort by minor
         */
        if (minor_hash1 > minor_hash2)
                return 1;
        if (minor_hash1 < minor_hash2)
                return -1;
        return 0;
}

static void dx_leaf_sort_swap(void *a, void *b, int size)
{
        struct ocfs2_dx_entry *entry1 = a;
        struct ocfs2_dx_entry *entry2 = b;
        struct ocfs2_dx_entry tmp;

        BUG_ON(size != sizeof(*entry1));

        tmp = *entry1;
        *entry1 = *entry2;
        *entry2 = tmp;
}

static int ocfs2_dx_leaf_same_major(struct ocfs2_dx_leaf *dx_leaf)
{
        struct ocfs2_dx_entry_list *dl_list = &dx_leaf->dl_list;
        int i, num = le16_to_cpu(dl_list->de_num_used);

        for (i = 0; i < (num - 1); i++) {
                if (le32_to_cpu(dl_list->de_entries[i].dx_major_hash) !=
                    le32_to_cpu(dl_list->de_entries[i + 1].dx_major_hash))
                        return 0;
        }

        return 1;
}

/*
 * Find the optimal value to split this leaf on. This expects the leaf
 * entries to be in sorted order.
 *
 * leaf_cpos is the cpos of the leaf we're splitting. insert_hash is
 * the hash we want to insert.
 *
 * This function is only concerned with the major hash - that which
 * determines which cluster an item belongs to.
 */
static int ocfs2_dx_dir_find_leaf_split(struct ocfs2_dx_leaf *dx_leaf,
                                        u32 leaf_cpos, u32 insert_hash,
                                        u32 *split_hash)
{
        struct ocfs2_dx_entry_list *dl_list = &dx_leaf->dl_list;
        int i, num_used = le16_to_cpu(dl_list->de_num_used);
        int allsame;

        /*
         * There's a couple rare, but nasty corner cases we have to
         * check for here. All of them involve a leaf where all value
         * have the same hash, which is what we look for first.
         *
         * Most of the time, all of the above is false, and we simply
         * pick the median value for a split.
         */
        allsame = ocfs2_dx_leaf_same_major(dx_leaf);
        if (allsame) {
                u32 val = le32_to_cpu(dl_list->de_entries[0].dx_major_hash);

                if (val == insert_hash) {
                        /*
                         * No matter where we would choose to split,
                         * the new entry would want to occupy the same
                         * block as these. Since there's no space left
                         * in their existing block, we know there
                         * won't be space after the split.
                         */
                        return -ENOSPC;
                }

                if (val == leaf_cpos) {
                        /*
                         * Because val is the same as leaf_cpos (which
                         * is the smallest value this leaf can have),
                         * yet is not equal to insert_hash, then we
                         * know that insert_hash *must* be larger than
                         * val (and leaf_cpos). At least cpos+1 in value.
                         *
                         * We also know then, that there cannot be an
                         * adjacent extent (otherwise we'd be looking
                         * at it). Choosing this value gives us a
                         * chance to get some contiguousness.
                         */
                        *split_hash = leaf_cpos + 1;
                        return 0;
                }

                if (val > insert_hash) {
                        /*
                         * val can not be the same as insert hash, and
                         * also must be larger than leaf_cpos. Also,
                         * we know that there can't be a leaf between
                         * cpos and val, otherwise the entries with
                         * hash 'val' would be there.
                         */
                        *split_hash = val;
                        return 0;
                }

                *split_hash = insert_hash;
                return 0;
        }

        /*
         * Since the records are sorted and the checks above
         * guaranteed that not all records in this block are the same,
         * we simple travel forward, from the median, and pick the 1st
         * record whose value is larger than leaf_cpos.
         */
        for (i = (num_used / 2); i < num_used; i++)
                if (le32_to_cpu(dl_list->de_entries[i].dx_major_hash) >
                    leaf_cpos)
                        break;

        BUG_ON(i == num_used); /* Should be impossible */
        *split_hash = le32_to_cpu(dl_list->de_entries[i].dx_major_hash);
        return 0;
}

/*
 * Transfer all entries in orig_dx_leaves whose major hash is equal to or
 * larger than split_hash into new_dx_leaves. We use a temporary
 * buffer (tmp_dx_leaf) to make the changes to the original leaf blocks.
 *
 * Since the block offset inside a leaf (cluster) is a constant mask
 * of minor_hash, we can optimize - an item at block offset X within
 * the original cluster, will be at offset X within the new cluster.
 */
static void ocfs2_dx_dir_transfer_leaf(struct inode *dir, u32 split_hash,
                                       handle_t *handle,
                                       struct ocfs2_dx_leaf *tmp_dx_leaf,
                                       struct buffer_head **orig_dx_leaves,
                                       struct buffer_head **new_dx_leaves,
                                       int num_dx_leaves)
{
        int i, j, num_used;
        u32 major_hash;
        struct ocfs2_dx_leaf *orig_dx_leaf, *new_dx_leaf;
        struct ocfs2_dx_entry_list *orig_list, *new_list, *tmp_list;
        struct ocfs2_dx_entry *dx_entry;

        tmp_list = &tmp_dx_leaf->dl_list;

        for (i = 0; i < num_dx_leaves; i++) {
                orig_dx_leaf = (struct ocfs2_dx_leaf *) orig_dx_leaves[i]->b_data;
                orig_list = &orig_dx_leaf->dl_list;
                new_dx_leaf = (struct ocfs2_dx_leaf *) new_dx_leaves[i]->b_data;
                new_list = &new_dx_leaf->dl_list;

                num_used = le16_to_cpu(orig_list->de_num_used);

                memcpy(tmp_dx_leaf, orig_dx_leaf, dir->i_sb->s_blocksize);
                tmp_list->de_num_used = cpu_to_le16(0);
                memset(&tmp_list->de_entries, 0, sizeof(*dx_entry)*num_used);

                for (j = 0; j < num_used; j++) {
                        dx_entry = &orig_list->de_entries[j];
                        major_hash = le32_to_cpu(dx_entry->dx_major_hash);
                        if (major_hash >= split_hash)
                                ocfs2_dx_dir_leaf_insert_tail(new_dx_leaf,
                                                              dx_entry);
                        else
                                ocfs2_dx_dir_leaf_insert_tail(tmp_dx_leaf,
                                                              dx_entry);
                }
                memcpy(orig_dx_leaf, tmp_dx_leaf, dir->i_sb->s_blocksize);

                ocfs2_journal_dirty(handle, orig_dx_leaves[i]);
                ocfs2_journal_dirty(handle, new_dx_leaves[i]);
        }
}

static int ocfs2_dx_dir_rebalance_credits(struct ocfs2_super *osb,
                                          struct ocfs2_dx_root_block *dx_root)
{
        int credits = ocfs2_clusters_to_blocks(osb->sb, 2);

        credits += ocfs2_calc_extend_credits(osb->sb, &dx_root->dr_list);
        credits += ocfs2_quota_trans_credits(osb->sb);
        return credits;
}

/*
 * Find the median value in dx_leaf_bh and allocate a new leaf to move
 * half our entries into.
 */
static int ocfs2_dx_dir_rebalance(struct ocfs2_super *osb, struct inode *dir,
                                  struct buffer_head *dx_root_bh,
                                  struct buffer_head *dx_leaf_bh,
                                  struct ocfs2_dx_hinfo *hinfo, u32 leaf_cpos,
                                  u64 leaf_blkno)
{
        struct ocfs2_dx_leaf *dx_leaf = (struct ocfs2_dx_leaf *)dx_leaf_bh->b_data;
        int credits, ret, i, num_used, did_quota = 0;
        u32 cpos, split_hash, insert_hash = hinfo->major_hash;
        u64 orig_leaves_start;
        int num_dx_leaves;
        struct buffer_head **orig_dx_leaves = NULL;
        struct buffer_head **new_dx_leaves = NULL;
        struct ocfs2_alloc_context *data_ac = NULL, *meta_ac = NULL;
        struct ocfs2_extent_tree et;
        handle_t *handle = NULL;
        struct ocfs2_dx_root_block *dx_root;
        struct ocfs2_dx_leaf *tmp_dx_leaf = NULL;

        trace_ocfs2_dx_dir_rebalance((unsigned long long)OCFS2_I(dir)->ip_blkno,
                                     (unsigned long long)leaf_blkno,
                                     insert_hash);

        ocfs2_init_dx_root_extent_tree(&et, INODE_CACHE(dir), dx_root_bh);

        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;
        /*
         * XXX: This is a rather large limit. We should use a more
         * realistic value.
         */
        if (le32_to_cpu(dx_root->dr_clusters) == UINT_MAX)
                return -ENOSPC;

        num_used = le16_to_cpu(dx_leaf->dl_list.de_num_used);
        if (num_used < le16_to_cpu(dx_leaf->dl_list.de_count)) {
                mlog(ML_ERROR, "DX Dir: %llu, Asked to rebalance empty leaf: "
                     "%llu, %d\n", (unsigned long long)OCFS2_I(dir)->ip_blkno,
                     (unsigned long long)leaf_blkno, num_used);
                ret = -EIO;
                goto out;
        }

        orig_dx_leaves = ocfs2_dx_dir_kmalloc_leaves(osb->sb, &num_dx_leaves);
        if (!orig_dx_leaves) {
                ret = -ENOMEM;
                mlog_errno(ret);
                goto out;
        }

        new_dx_leaves = ocfs2_dx_dir_kmalloc_leaves(osb->sb, NULL);
        if (!new_dx_leaves) {
                ret = -ENOMEM;
                mlog_errno(ret);
                goto out;
        }

        ret = ocfs2_lock_allocators(dir, &et, 1, 0, &data_ac, &meta_ac);
        if (ret) {
                if (ret != -ENOSPC)
                        mlog_errno(ret);
                goto out;
        }

        credits = ocfs2_dx_dir_rebalance_credits(osb, dx_root);
        handle = ocfs2_start_trans(osb, credits);
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
                handle = NULL;
                mlog_errno(ret);
                goto out;
        }

        ret = dquot_alloc_space_nodirty(dir,
                                       ocfs2_clusters_to_bytes(dir->i_sb, 1));
        if (ret)
                goto out_commit;
        did_quota = 1;

        ret = ocfs2_journal_access_dl(handle, INODE_CACHE(dir), dx_leaf_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        /*
         * This block is changing anyway, so we can sort it in place.
         */
        sort(dx_leaf->dl_list.de_entries, num_used,
             sizeof(struct ocfs2_dx_entry), dx_leaf_sort_cmp,
             dx_leaf_sort_swap);

        ocfs2_journal_dirty(handle, dx_leaf_bh);

        ret = ocfs2_dx_dir_find_leaf_split(dx_leaf, leaf_cpos, insert_hash,
                                           &split_hash);
        if (ret) {
                mlog_errno(ret);
                goto  out_commit;
        }

        trace_ocfs2_dx_dir_rebalance_split(leaf_cpos, split_hash, insert_hash);

        /*
         * We have to carefully order operations here. There are items
         * which want to be in the new cluster before insert, but in
         * order to put those items in the new cluster, we alter the
         * old cluster. A failure to insert gets nasty.
         *
         * So, start by reserving writes to the old
         * cluster. ocfs2_dx_dir_new_cluster will reserve writes on
         * the new cluster for us, before inserting it. The insert
         * won't happen if there's an error before that. Once the
         * insert is done then, we can transfer from one leaf into the
         * other without fear of hitting any error.
         */

        /*
         * The leaf transfer wants some scratch space so that we don't
         * wind up doing a bunch of expensive memmove().
         */
        tmp_dx_leaf = kmalloc(osb->sb->s_blocksize, GFP_NOFS);
        if (!tmp_dx_leaf) {
                ret = -ENOMEM;
                mlog_errno(ret);
                goto out_commit;
        }

        orig_leaves_start = ocfs2_block_to_cluster_start(dir->i_sb, leaf_blkno);
        ret = ocfs2_read_dx_leaves(dir, orig_leaves_start, num_dx_leaves,
                                   orig_dx_leaves);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        cpos = split_hash;
        ret = ocfs2_dx_dir_new_cluster(dir, &et, cpos, handle,
                                       data_ac, meta_ac, new_dx_leaves,
                                       num_dx_leaves);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        for (i = 0; i < num_dx_leaves; i++) {
                ret = ocfs2_journal_access_dl(handle, INODE_CACHE(dir),
                                              orig_dx_leaves[i],
                                              OCFS2_JOURNAL_ACCESS_WRITE);
                if (ret) {
                        mlog_errno(ret);
                        goto out_commit;
                }

                ret = ocfs2_journal_access_dl(handle, INODE_CACHE(dir),
                                              new_dx_leaves[i],
                                              OCFS2_JOURNAL_ACCESS_WRITE);
                if (ret) {
                        mlog_errno(ret);
                        goto out_commit;
                }
        }

        ocfs2_dx_dir_transfer_leaf(dir, split_hash, handle, tmp_dx_leaf,
                                   orig_dx_leaves, new_dx_leaves, num_dx_leaves);

out_commit:
        if (ret < 0 && did_quota)
                dquot_free_space_nodirty(dir,
                                ocfs2_clusters_to_bytes(dir->i_sb, 1));

        ocfs2_update_inode_fsync_trans(handle, dir, 1);
        ocfs2_commit_trans(osb, handle);

out:
        if (orig_dx_leaves || new_dx_leaves) {
                for (i = 0; i < num_dx_leaves; i++) {
                        if (orig_dx_leaves)
                                brelse(orig_dx_leaves[i]);
                        if (new_dx_leaves)
                                brelse(new_dx_leaves[i]);
                }
                kfree(orig_dx_leaves);
                kfree(new_dx_leaves);
        }

        if (meta_ac)
                ocfs2_free_alloc_context(meta_ac);
        if (data_ac)
                ocfs2_free_alloc_context(data_ac);

        kfree(tmp_dx_leaf);
        return ret;
}

static int ocfs2_find_dir_space_dx(struct ocfs2_super *osb, struct inode *dir,
                                   struct buffer_head *di_bh,
                                   struct buffer_head *dx_root_bh,
                                   const char *name, int namelen,
                                   struct ocfs2_dir_lookup_result *lookup)
{
        int ret, rebalanced = 0;
        struct ocfs2_dx_root_block *dx_root;
        struct buffer_head *dx_leaf_bh = NULL;
        struct ocfs2_dx_leaf *dx_leaf;
        u64 blkno;
        u32 leaf_cpos;

        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;

restart_search:
        ret = ocfs2_dx_dir_lookup(dir, &dx_root->dr_list, &lookup->dl_hinfo,
                                  &leaf_cpos, &blkno);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        ret = ocfs2_read_dx_leaf(dir, blkno, &dx_leaf_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        dx_leaf = (struct ocfs2_dx_leaf *)dx_leaf_bh->b_data;

        if (le16_to_cpu(dx_leaf->dl_list.de_num_used) >=
            le16_to_cpu(dx_leaf->dl_list.de_count)) {
                if (rebalanced) {
                        /*
                         * Rebalancing should have provided us with
                         * space in an appropriate leaf.
                         *
                         * XXX: Is this an abnormal condition then?
                         * Should we print a message here?
                         */
                        ret = -ENOSPC;
                        goto out;
                }

                ret = ocfs2_dx_dir_rebalance(osb, dir, dx_root_bh, dx_leaf_bh,
                                             &lookup->dl_hinfo, leaf_cpos,
                                             blkno);
                if (ret) {
                        if (ret != -ENOSPC)
                                mlog_errno(ret);
                        goto out;
                }

                /*
                 * Restart the lookup. The rebalance might have
                 * changed which block our item fits into. Mark our
                 * progress, so we only execute this once.
                 */
                brelse(dx_leaf_bh);
                dx_leaf_bh = NULL;
                rebalanced = 1;
                goto restart_search;
        }

        lookup->dl_dx_leaf_bh = dx_leaf_bh;
        dx_leaf_bh = NULL;

out:
        brelse(dx_leaf_bh);
        return ret;
}

static int ocfs2_search_dx_free_list(struct inode *dir,
                                     struct buffer_head *dx_root_bh,
                                     int namelen,
                                     struct ocfs2_dir_lookup_result *lookup)
{
        int ret = -ENOSPC;
        struct buffer_head *leaf_bh = NULL, *prev_leaf_bh = NULL;
        struct ocfs2_dir_block_trailer *db;
        u64 next_block;
        int rec_len = OCFS2_DIR_REC_LEN(namelen);
        struct ocfs2_dx_root_block *dx_root;

        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;
        next_block = le64_to_cpu(dx_root->dr_free_blk);

        while (next_block) {
                brelse(prev_leaf_bh);
                prev_leaf_bh = leaf_bh;
                leaf_bh = NULL;

                ret = ocfs2_read_dir_block_direct(dir, next_block, &leaf_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                db = ocfs2_trailer_from_bh(leaf_bh, dir->i_sb);
                if (rec_len <= le16_to_cpu(db->db_free_rec_len)) {
                        lookup->dl_leaf_bh = leaf_bh;
                        lookup->dl_prev_leaf_bh = prev_leaf_bh;
                        leaf_bh = NULL;
                        prev_leaf_bh = NULL;
                        break;
                }

                next_block = le64_to_cpu(db->db_free_next);
        }

        if (!next_block)
                ret = -ENOSPC;

out:

        brelse(leaf_bh);
        brelse(prev_leaf_bh);
        return ret;
}

static int ocfs2_expand_inline_dx_root(struct inode *dir,
                                       struct buffer_head *dx_root_bh)
{
        int ret, num_dx_leaves, i, j, did_quota = 0;
        struct buffer_head **dx_leaves = NULL;
        struct ocfs2_extent_tree et;
        u64 insert_blkno;
        struct ocfs2_alloc_context *data_ac = NULL;
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
        handle_t *handle = NULL;
        struct ocfs2_dx_root_block *dx_root;
        struct ocfs2_dx_entry_list *entry_list;
        struct ocfs2_dx_entry *dx_entry;
        struct ocfs2_dx_leaf *target_leaf;

        ret = ocfs2_reserve_clusters(osb, 1, &data_ac);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        dx_leaves = ocfs2_dx_dir_kmalloc_leaves(osb->sb, &num_dx_leaves);
        if (!dx_leaves) {
                ret = -ENOMEM;
                mlog_errno(ret);
                goto out;
        }

        handle = ocfs2_start_trans(osb, ocfs2_calc_dxi_expand_credits(osb->sb));
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
                mlog_errno(ret);
                goto out;
        }

        ret = dquot_alloc_space_nodirty(dir,
                                       ocfs2_clusters_to_bytes(osb->sb, 1));
        if (ret)
                goto out_commit;
        did_quota = 1;

        /*
         * We do this up front, before the allocation, so that a
         * failure to add the dx_root_bh to the journal won't result
         * us losing clusters.
         */
        ret = ocfs2_journal_access_dr(handle, INODE_CACHE(dir), dx_root_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        ret = __ocfs2_dx_dir_new_cluster(dir, 0, handle, data_ac, dx_leaves,
                                         num_dx_leaves, &insert_blkno);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        /*
         * Transfer the entries from our dx_root into the appropriate
         * block
         */
        dx_root = (struct ocfs2_dx_root_block *) dx_root_bh->b_data;
        entry_list = &dx_root->dr_entries;

        for (i = 0; i < le16_to_cpu(entry_list->de_num_used); i++) {
                dx_entry = &entry_list->de_entries[i];

                j = __ocfs2_dx_dir_hash_idx(osb,
                                            le32_to_cpu(dx_entry->dx_minor_hash));
                target_leaf = (struct ocfs2_dx_leaf *)dx_leaves[j]->b_data;

                ocfs2_dx_dir_leaf_insert_tail(target_leaf, dx_entry);

                /* Each leaf has been passed to the journal already
                 * via __ocfs2_dx_dir_new_cluster() */
        }

        dx_root->dr_flags &= ~OCFS2_DX_FLAG_INLINE;
        memset(&dx_root->dr_list, 0, osb->sb->s_blocksize -
               offsetof(struct ocfs2_dx_root_block, dr_list));
        dx_root->dr_list.l_count =
                cpu_to_le16(ocfs2_extent_recs_per_dx_root(osb->sb));

        /* This should never fail considering we start with an empty
         * dx_root. */
        ocfs2_init_dx_root_extent_tree(&et, INODE_CACHE(dir), dx_root_bh);
        ret = ocfs2_insert_extent(handle, &et, 0, insert_blkno, 1, 0, NULL);
        if (ret)
                mlog_errno(ret);
        did_quota = 0;

        ocfs2_update_inode_fsync_trans(handle, dir, 1);
        ocfs2_journal_dirty(handle, dx_root_bh);

out_commit:
        if (ret < 0 && did_quota)
                dquot_free_space_nodirty(dir,
                                          ocfs2_clusters_to_bytes(dir->i_sb, 1));

        ocfs2_commit_trans(osb, handle);

out:
        if (data_ac)
                ocfs2_free_alloc_context(data_ac);

        if (dx_leaves) {
                for (i = 0; i < num_dx_leaves; i++)
                        brelse(dx_leaves[i]);
                kfree(dx_leaves);
        }
        return ret;
}

static int ocfs2_inline_dx_has_space(struct buffer_head *dx_root_bh)
{
        struct ocfs2_dx_root_block *dx_root;
        struct ocfs2_dx_entry_list *entry_list;

        dx_root = (struct ocfs2_dx_root_block *) dx_root_bh->b_data;
        entry_list = &dx_root->dr_entries;

        if (le16_to_cpu(entry_list->de_num_used) >=
            le16_to_cpu(entry_list->de_count))
                return -ENOSPC;

        return 0;
}

static int ocfs2_prepare_dx_dir_for_insert(struct inode *dir,
                                           struct buffer_head *di_bh,
                                           const char *name,
                                           int namelen,
                                           struct ocfs2_dir_lookup_result *lookup)
{
        int ret, free_dx_root = 1;
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
        struct buffer_head *dx_root_bh = NULL;
        struct buffer_head *leaf_bh = NULL;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
        struct ocfs2_dx_root_block *dx_root;

        ret = ocfs2_read_dx_root(dir, di, &dx_root_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;
        if (le32_to_cpu(dx_root->dr_num_entries) == OCFS2_DX_ENTRIES_MAX) {
                ret = -ENOSPC;
                mlog_errno(ret);
                goto out;
        }

        if (ocfs2_dx_root_inline(dx_root)) {
                ret = ocfs2_inline_dx_has_space(dx_root_bh);

                if (ret == 0)
                        goto search_el;

                /*
                 * We ran out of room in the root block. Expand it to
                 * an extent, then allow ocfs2_find_dir_space_dx to do
                 * the rest.
                 */
                ret = ocfs2_expand_inline_dx_root(dir, dx_root_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }
        }

        /*
         * Insert preparation for an indexed directory is split into two
         * steps. The call to find_dir_space_dx reserves room in the index for
         * an additional item. If we run out of space there, it's a real error
         * we can't continue on.
         */
        ret = ocfs2_find_dir_space_dx(osb, dir, di_bh, dx_root_bh, name,
                                      namelen, lookup);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

search_el:
        /*
         * Next, we need to find space in the unindexed tree. This call
         * searches using the free space linked list. If the unindexed tree
         * lacks sufficient space, we'll expand it below. The expansion code
         * is smart enough to add any new blocks to the free space list.
         */
        ret = ocfs2_search_dx_free_list(dir, dx_root_bh, namelen, lookup);
        if (ret && ret != -ENOSPC) {
                mlog_errno(ret);
                goto out;
        }

        /* Do this up here - ocfs2_extend_dir might need the dx_root */
        lookup->dl_dx_root_bh = dx_root_bh;
        free_dx_root = 0;

        if (ret == -ENOSPC) {
                ret = ocfs2_extend_dir(osb, dir, di_bh, 1, lookup, &leaf_bh);

                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                /*
                 * We make the assumption here that new leaf blocks are added
                 * to the front of our free list.
                 */
                lookup->dl_prev_leaf_bh = NULL;
                lookup->dl_leaf_bh = leaf_bh;
        }

out:
        if (free_dx_root)
                brelse(dx_root_bh);
        return ret;
}

/*
 * Get a directory ready for insert. Any directory allocation required
 * happens here. Success returns zero, and enough context in the dir
 * lookup result that ocfs2_add_entry() will be able complete the task
 * with minimal performance impact.
 */
int ocfs2_prepare_dir_for_insert(struct ocfs2_super *osb,
                                 struct inode *dir,
                                 struct buffer_head *parent_fe_bh,
                                 const char *name,
                                 int namelen,
                                 struct ocfs2_dir_lookup_result *lookup)
{
        int ret;
        unsigned int blocks_wanted = 1;
        struct buffer_head *bh = NULL;

        trace_ocfs2_prepare_dir_for_insert(
                (unsigned long long)OCFS2_I(dir)->ip_blkno, namelen);

        if (!namelen) {
                ret = -EINVAL;
                mlog_errno(ret);
                goto out;
        }

        /*
         * Do this up front to reduce confusion.
         *
         * The directory might start inline, then be turned into an
         * indexed one, in which case we'd need to hash deep inside
         * ocfs2_find_dir_space_id(). Since
         * ocfs2_prepare_dx_dir_for_insert() also needs this hash
         * done, there seems no point in spreading out the calls. We
         * can optimize away the case where the file system doesn't
         * support indexing.
         */
        if (ocfs2_supports_indexed_dirs(osb))
                ocfs2_dx_dir_name_hash(dir, name, namelen, &lookup->dl_hinfo);

        if (ocfs2_dir_indexed(dir)) {
                ret = ocfs2_prepare_dx_dir_for_insert(dir, parent_fe_bh,
                                                      name, namelen, lookup);
                if (ret)
                        mlog_errno(ret);
                goto out;
        }

        if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
                ret = ocfs2_find_dir_space_id(dir, parent_fe_bh, name,
                                              namelen, &bh, &blocks_wanted);
        } else
                ret = ocfs2_find_dir_space_el(dir, name, namelen, &bh);

        if (ret && ret != -ENOSPC) {
                mlog_errno(ret);
                goto out;
        }

        if (ret == -ENOSPC) {
                /*
                 * We have to expand the directory to add this name.
                 */
                BUG_ON(bh);

                ret = ocfs2_extend_dir(osb, dir, parent_fe_bh, blocks_wanted,
                                       lookup, &bh);
                if (ret) {
                        if (ret != -ENOSPC)
                                mlog_errno(ret);
                        goto out;
                }

                BUG_ON(!bh);
        }

        lookup->dl_leaf_bh = bh;
        bh = NULL;
out:
        brelse(bh);
        return ret;
}

static int ocfs2_dx_dir_remove_index(struct inode *dir,
                                     struct buffer_head *di_bh,
                                     struct buffer_head *dx_root_bh)
{
        int ret;
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
        struct ocfs2_dx_root_block *dx_root;
        struct inode *dx_alloc_inode = NULL;
        struct buffer_head *dx_alloc_bh = NULL;
        handle_t *handle;
        u64 blk;
        u16 bit;
        u64 bg_blkno;

        dx_root = (struct ocfs2_dx_root_block *) dx_root_bh->b_data;

        dx_alloc_inode = ocfs2_get_system_file_inode(osb,
                                        EXTENT_ALLOC_SYSTEM_INODE,
                                        le16_to_cpu(dx_root->dr_suballoc_slot));
        if (!dx_alloc_inode) {
                ret = -ENOMEM;
                mlog_errno(ret);
                goto out;
        }
        mutex_lock(&dx_alloc_inode->i_mutex);

        ret = ocfs2_inode_lock(dx_alloc_inode, &dx_alloc_bh, 1);
        if (ret) {
                mlog_errno(ret);
                goto out_mutex;
        }

        handle = ocfs2_start_trans(osb, OCFS2_DX_ROOT_REMOVE_CREDITS);
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
                mlog_errno(ret);
                goto out_unlock;
        }

        ret = ocfs2_journal_access_di(handle, INODE_CACHE(dir), di_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        spin_lock(&OCFS2_I(dir)->ip_lock);
        OCFS2_I(dir)->ip_dyn_features &= ~OCFS2_INDEXED_DIR_FL;
        di->i_dyn_features = cpu_to_le16(OCFS2_I(dir)->ip_dyn_features);
        spin_unlock(&OCFS2_I(dir)->ip_lock);
        di->i_dx_root = cpu_to_le64(0ULL);
        ocfs2_update_inode_fsync_trans(handle, dir, 1);

        ocfs2_journal_dirty(handle, di_bh);

        blk = le64_to_cpu(dx_root->dr_blkno);
        bit = le16_to_cpu(dx_root->dr_suballoc_bit);
        if (dx_root->dr_suballoc_loc)
                bg_blkno = le64_to_cpu(dx_root->dr_suballoc_loc);
        else
                bg_blkno = ocfs2_which_suballoc_group(blk, bit);
        ret = ocfs2_free_suballoc_bits(handle, dx_alloc_inode, dx_alloc_bh,
                                       bit, bg_blkno, 1);
        if (ret)
                mlog_errno(ret);

out_commit:
        ocfs2_commit_trans(osb, handle);

out_unlock:
        ocfs2_inode_unlock(dx_alloc_inode, 1);

out_mutex:
        mutex_unlock(&dx_alloc_inode->i_mutex);
        brelse(dx_alloc_bh);
out:
        iput(dx_alloc_inode);
        return ret;
}

int ocfs2_dx_dir_truncate(struct inode *dir, struct buffer_head *di_bh)
{
        int ret;
        unsigned int uninitialized_var(clen);
        u32 major_hash = UINT_MAX, p_cpos, uninitialized_var(cpos);
        u64 uninitialized_var(blkno);
        struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
        struct buffer_head *dx_root_bh = NULL;
        struct ocfs2_dx_root_block *dx_root;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
        struct ocfs2_cached_dealloc_ctxt dealloc;
        struct ocfs2_extent_tree et;

        ocfs2_init_dealloc_ctxt(&dealloc);

        if (!ocfs2_dir_indexed(dir))
                return 0;

        ret = ocfs2_read_dx_root(dir, di, &dx_root_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
        dx_root = (struct ocfs2_dx_root_block *)dx_root_bh->b_data;

        if (ocfs2_dx_root_inline(dx_root))
                goto remove_index;

        ocfs2_init_dx_root_extent_tree(&et, INODE_CACHE(dir), dx_root_bh);

        /* XXX: What if dr_clusters is too large? */
        while (le32_to_cpu(dx_root->dr_clusters)) {
                ret = ocfs2_dx_dir_lookup_rec(dir, &dx_root->dr_list,
                                              major_hash, &cpos, &blkno, &clen);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                p_cpos = ocfs2_blocks_to_clusters(dir->i_sb, blkno);

                ret = ocfs2_remove_btree_range(dir, &et, cpos, p_cpos, clen, 0,
                                               &dealloc, 0, false);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }

                if (cpos == 0)
                        break;

                major_hash = cpos - 1;
        }

remove_index:
        ret = ocfs2_dx_dir_remove_index(dir, di_bh, dx_root_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }

        ocfs2_remove_from_cache(INODE_CACHE(dir), dx_root_bh);
out:
        ocfs2_schedule_truncate_log_flush(osb, 1);
        ocfs2_run_deallocs(osb, &dealloc);

        brelse(dx_root_bh);
        return ret;
}