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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 Linux 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>

#define MLOG_MASK_PREFIX ML_NAMEI
#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 "buffer_head_io.h"

#define NAMEI_RA_CHUNKS  2
#define NAMEI_RA_BLOCKS  4
#define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
#define NAMEI_RA_INDEX(c,b)  (((c) * NAMEI_RA_BLOCKS) + (b))

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

      if (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 int inline 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;

      mlog_entry_void();

      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:
      mlog_exit(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.
       */
      mlog(0, "Validating dirblock %llu\n",
           (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(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(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(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(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;

      mlog_entry_void();

      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. */
                  ocfs2_error(dir->i_sb, "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]);

      mlog_exit_ptr(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, 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;
      }

      mlog(0, "Dir %llu: name: \"%.*s\", lookup of hash: %u.0x%x "
           "returns: %llu\n",
           (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;

      mlog(0, "leaf info: num_used: %d, count: %d\n",
           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, 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;

      mlog_entry("(0x%p, 0x%p, 0x%p, 0x%p)\n", handle, dir, de_del, bh);

      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, 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));
                  else
                        de->inode = 0;
                  dir->i_version++;
                  status = 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:
      mlog_exit(status);
      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, 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, dir,
                                    lookup->dl_dx_leaf_bh,
                                    OCFS2_JOURNAL_ACCESS_WRITE);
            if (ret) {
                  mlog_errno(ret);
                  goto out;
            }
      }

      mlog(0, "Dir %llu: delete entry at index: %d\n",
           (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, 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, 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;

      mlog_entry_void();

      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, dir, bh,
                                     OCFS2_JOURNAL_ACCESS_WRITE);
            } else {
                  bh = lookup->dl_prev_leaf_bh;
                  retval = ocfs2_journal_access_db(handle, 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, dir,
                                                 insert_bh,
                                                 OCFS2_JOURNAL_ACCESS_WRITE);
                  else {
                        status = ocfs2_journal_access_db(handle, 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++;
                  status = 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:

      mlog_exit(retval);
      return retval;
}

static int ocfs2_dir_foreach_blk_id(struct inode *inode,
                            u64 *f_version,
                            loff_t *f_pos, void *priv,
                            filldir_t filldir, int *filldir_err)
{
      int ret, i, filldir_ret;
      unsigned long offset = *f_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 (*f_pos < i_size_read(inode)) {
revalidate:
            /* 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);
                  }
                  *f_pos = offset = i;
                  *f_version = inode->i_version;
            }

            de = (struct ocfs2_dir_entry *) (data->id_data + *f_pos);
            if (!ocfs2_check_dir_entry(inode, de, di_bh, *f_pos)) {
                  /* On error, skip the f_pos to the end. */
                  *f_pos = i_size_read(inode);
                  goto out;
            }
            offset += le16_to_cpu(de->rec_len);
            if (le64_to_cpu(de->inode)) {
                  /* We might block in the next section
                   * if the data destination is
                   * currently swapped out.  So, use a
                   * version stamp to detect whether or
                   * not the directory has been modified
                   * during the copy operation.
                   */
                  u64 version = *f_version;
                  unsigned char d_type = DT_UNKNOWN;

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

                  filldir_ret = filldir(priv, de->name,
                                    de->name_len,
                                    *f_pos,
                                    le64_to_cpu(de->inode),
                                    d_type);
                  if (filldir_ret) {
                        if (filldir_err)
                              *filldir_err = filldir_ret;
                        break;
                  }
                  if (version != *f_version)
                        goto revalidate;
            }
            *f_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,
                            loff_t *f_pos, void *priv,
                            filldir_t filldir, int *filldir_err)
{
      int error = 0;
      unsigned long offset, blk, last_ra_blk = 0;
      int i, stored;
      struct buffer_head * bh, * tmp;
      struct ocfs2_dir_entry * de;
      struct super_block * sb = inode->i_sb;
      unsigned int ra_sectors = 16;

      stored = 0;
      bh = NULL;

      offset = (*f_pos) & (sb->s_blocksize - 1);

      while (!error && !stored && *f_pos < i_size_read(inode)) {
            blk = (*f_pos) >> sb->s_blocksize_bits;
            if (ocfs2_read_dir_block(inode, blk, &bh, 0)) {
                  /* Skip the corrupt dirblock and keep trying */
                  *f_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;
            }

revalidate:
            /* 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;
                  *f_pos = ((*f_pos) & ~(sb->s_blocksize - 1))
                        | offset;
                  *f_version = inode->i_version;
            }

            while (!error && *f_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. */
                        *f_pos = ((*f_pos) | (sb->s_blocksize - 1)) + 1;
                        brelse(bh);
                        goto out;
                  }
                  offset += le16_to_cpu(de->rec_len);
                  if (le64_to_cpu(de->inode)) {
                        /* We might block in the next section
                         * if the data destination is
                         * currently swapped out.  So, use a
                         * version stamp to detect whether or
                         * not the directory has been modified
                         * during the copy operation.
                         */
                        unsigned long version = *f_version;
                        unsigned char d_type = DT_UNKNOWN;

                        if (de->file_type < OCFS2_FT_MAX)
                              d_type = ocfs2_filetype_table[de->file_type];
                        error = filldir(priv, de->name,
                                    de->name_len,
                                    *f_pos,
                                    le64_to_cpu(de->inode),
                                    d_type);
                        if (error) {
                              if (filldir_err)
                                    *filldir_err = error;
                              break;
                        }
                        if (version != *f_version)
                              goto revalidate;
                        stored ++;
                  }
                  *f_pos += le16_to_cpu(de->rec_len);
            }
            offset = 0;
            brelse(bh);
            bh = NULL;
      }

      stored = 0;
out:
      return stored;
}

static int ocfs2_dir_foreach_blk(struct inode *inode, u64 *f_version,
                         loff_t *f_pos, void *priv, filldir_t filldir,
                         int *filldir_err)
{
      if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
            return ocfs2_dir_foreach_blk_id(inode, f_version, f_pos, priv,
                                    filldir, filldir_err);

      return ocfs2_dir_foreach_blk_el(inode, f_version, f_pos, priv, filldir,
                              filldir_err);
}

/*
 * This is intended to be called from inside other kernel functions,
 * so we fake some arguments.
 */
int ocfs2_dir_foreach(struct inode *inode, loff_t *f_pos, void *priv,
                  filldir_t filldir)
{
      int ret = 0, filldir_err = 0;
      u64 version = inode->i_version;

      while (*f_pos < i_size_read(inode)) {
            ret = ocfs2_dir_foreach_blk(inode, &version, f_pos, priv,
                                  filldir, &filldir_err);
            if (ret || filldir_err)
                  break;
      }

      if (ret > 0)
            ret = -EIO;

      return 0;
}

/*
 * ocfs2_readdir()
 *
 */
int ocfs2_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
      int error = 0;
      struct inode *inode = filp->f_path.dentry->d_inode;
      int lock_level = 0;

      mlog_entry("dirino=%llu\n",
               (unsigned long long)OCFS2_I(inode)->ip_blkno);

      error = ocfs2_inode_lock_atime(inode, filp->f_vfsmnt, &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, &filp->f_version, &filp->f_pos,
                              dirent, filldir, NULL);

      ocfs2_inode_unlock(inode, lock_level);

bail_nolock:
      mlog_exit(error);

      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;

      mlog(0, "name=%.*s, blkno=%p, inode=%llu\n", 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;
      struct ocfs2_dir_lookup_result lookup = { NULL, };

      mlog_entry("dir %llu, name '%.*s'\n",
               (unsigned long long)OCFS2_I(dir)->ip_blkno, namelen, name);

      ret = -EEXIST;
      if (ocfs2_find_entry(name, namelen, dir, &lookup) == 0)
            goto bail;

      ret = 0;
bail:
      ocfs2_free_dir_lookup_result(&lookup);

      mlog_exit(ret);
      return ret;
}

02123 struct ocfs2_empty_dir_priv {
      unsigned seen_dot;
      unsigned seen_dot_dot;
      unsigned seen_other;
      unsigned dx_dir;
};
static int ocfs2_empty_dir_filldir(void *priv, const char *name, int name_len,
                           loff_t pos, u64 ino, unsigned type)
{
      struct ocfs2_empty_dir_priv *p = priv;

      /*
       * 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;
      loff_t start = 0;
      struct ocfs2_empty_dir_priv priv;

      memset(&priv, 0, sizeof(priv));

      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, &start, &priv, ocfs2_empty_dir_filldir);
      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, 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);
      if (ret) {
            mlog_errno(ret);
            goto out;
      }

      i_size_write(inode, size);
      inode->i_nlink = 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;

      mlog_entry_void();

      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, new_bh);

      status = ocfs2_journal_access_db(handle, 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);
      }

      status = ocfs2_journal_dirty(handle, new_bh);
      if (status < 0) {
            mlog_errno(status);
            goto bail;
      }

      i_size_write(inode, inode->i_sb->s_blocksize);
      inode->i_nlink = 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);

      mlog_exit(status);
      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 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(osb, handle, meta_ac, 1, &dr_suballoc_bit,
                           &num_bits, &dr_blkno);
      if (ret) {
            mlog_errno(ret);
            goto out;
      }

      mlog(0, "Dir %llu, attach new index block: %llu\n",
           (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 = -EIO;
            goto out;
      }
      ocfs2_set_new_buffer_uptodate(dir, dx_root_bh);

      ret = ocfs2_journal_access_dr(handle, 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(osb->slot_num);
      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));
      }

      ret = ocfs2_journal_dirty(handle, dx_root_bh);
      if (ret)
            mlog_errno(ret);

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

      di->i_dx_root = cpu_to_le64(dr_blkno);

      OCFS2_I(dir)->ip_dyn_features |= OCFS2_INDEXED_DIR_FL;
      di->i_dyn_features = cpu_to_le16(OCFS2_I(dir)->ip_dyn_features);

      ret = ocfs2_journal_dirty(handle, di_bh);
      if (ret)
            mlog_errno(ret);

      *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 = -EIO;
                  goto out;
            }
            dx_leaves[i] = bh;

            ocfs2_set_new_buffer_uptodate(dir, bh);

            ret = ocfs2_journal_access_dl(handle, 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));

            mlog(0,
                 "Dir %llu, format dx_leaf: %llu, entry count: %u\n",
                 (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(osb, 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;
      struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);

      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(osb, handle, dir, 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);

            mlog(0,
                 "dir: %llu, major: 0x%x minor: 0x%x, index: %u, name: %.*s\n",
                 (unsigned long long)dir->i_ino, hinfo.major_hash,
                 hinfo.minor_hash,
                 le16_to_cpu(dx_root->dr_entries.de_num_used),
                 de->name_len, de->name);

            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;
      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, 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;
      }

      if (vfs_dq_alloc_space_nodirty(dir,
                        ocfs2_clusters_to_bytes(osb->sb,
                                          alloc + dx_alloc))) {
            ret = -EDQUOT;
            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.
       */
      ret = ocfs2_claim_clusters(osb, 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 = -EIO;
            mlog_errno(ret);
            goto out_commit;
      }

      ocfs2_set_new_buffer_uptodate(dir, dirdata_bh);

      ret = ocfs2_journal_access_db(handle, 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);
      }

      ret = ocfs2_journal_dirty(handle, dirdata_bh);
      if (ret) {
            mlog_errno(ret);
            goto out_commit;
      }

      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, 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);

      /*
       * This should never fail as our extent list is empty and all
       * related blocks have been journaled already.
       */
      ret = ocfs2_insert_extent(osb, handle, dir, &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);

      ret = ocfs2_journal_dirty(handle, di_bh);
      if (ret) {
            mlog_errno(ret);
            goto out_commit;
      }

      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, dir, dx_root_bh);
                  ret = ocfs2_insert_extent(osb, handle, dir, &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(osb, 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(osb, handle, dir, &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)
            vfs_dq_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;

            if (vfs_dq_alloc_space_nodirty(dir,
                              ocfs2_clusters_to_bytes(sb, 1))) {
                  status = -EDQUOT;
                  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 = -EIO;
            mlog_errno(status);
            goto bail;
      }
      status = 0;
bail:
      if (did_quota && status < 0)
            vfs_dq_free_space_nodirty(dir, ocfs2_clusters_to_bytes(sb, 1));
      mlog_exit(status);
      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;

      mlog_entry_void();

      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);
      mlog(0, "extending dir %llu (i_size = %lld)\n",
           (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, dir, parent_fe_bh);
            num_free_extents = ocfs2_num_free_extents(osb, dir, &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;
            }

            credits = ocfs2_calc_extend_credits(sb, el, 1);
      } 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(dir, new_bh);

      status = ocfs2_journal_access_db(handle, 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);
      }
      status = ocfs2_journal_dirty(handle, new_bh);
      if (status < 0) {
            mlog_errno(status);
            goto bail;
      }

      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);

      mlog_exit(status);
      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) {
            mlog_errno(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) {
                        mlog_errno(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));
      }

      status = 0;
bail:
      brelse(bh);

      mlog_exit(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, 1);
      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;

      mlog(0, "DX Dir: %llu, rebalance leaf leaf_blkno: %llu insert: %u\n",
           (unsigned long long)OCFS2_I(dir)->ip_blkno,
           (unsigned long long)leaf_blkno, insert_hash);

      ocfs2_init_dx_root_extent_tree(&et, 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;
      }

      if (vfs_dq_alloc_space_nodirty(dir,
                               ocfs2_clusters_to_bytes(dir->i_sb, 1))) {
            ret = -EDQUOT;
            goto out_commit;
      }
      did_quota = 1;

      ret = ocfs2_journal_access_dl(handle, 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);

      ret = ocfs2_journal_dirty(handle, dx_leaf_bh);
      if (ret) {
            mlog_errno(ret);
            goto out_commit;
      }

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

      mlog(0, "Split leaf (%u) at %u, insert major hash is %u\n",
           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;
      }

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

      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)
            vfs_dq_free_space_nodirty(dir,
                        ocfs2_clusters_to_bytes(dir->i_sb, 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;
      }

      if (vfs_dq_alloc_space_nodirty(dir,
                               ocfs2_clusters_to_bytes(osb->sb, 1))) {
            ret = -EDQUOT;
            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, 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, dir, dx_root_bh);
      ret = ocfs2_insert_extent(osb, handle, dir, &et, 0,
                          insert_blkno, 1, 0, NULL);
      if (ret)
            mlog_errno(ret);
      did_quota = 0;

      ocfs2_journal_dirty(handle, dx_root_bh);

out_commit:
      if (ret < 0 && did_quota)
            vfs_dq_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;

      mlog(0, "getting ready to insert namelen %d into dir %llu\n",
           namelen, (unsigned long long)OCFS2_I(dir)->ip_blkno);

      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, dir, di_bh,
                              OCFS2_JOURNAL_ACCESS_WRITE);
      if (ret) {
            mlog_errno(ret);
            goto out_commit;
      }

      OCFS2_I(dir)->ip_dyn_features &= ~OCFS2_INDEXED_DIR_FL;
      di->i_dyn_features = cpu_to_le16(OCFS2_I(dir)->ip_dyn_features);
      di->i_dx_root = cpu_to_le64(0ULL);

      ocfs2_journal_dirty(handle, di_bh);

      blk = le64_to_cpu(dx_root->dr_blkno);
      bit = le16_to_cpu(dx_root->dr_suballoc_bit);
      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, 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,
                                     &dealloc);
            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(dir, dx_root_bh);
out:
      ocfs2_schedule_truncate_log_flush(osb, 1);
      ocfs2_run_deallocs(osb, &dealloc);

      brelse(dx_root_bh);
      return ret;
}

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