/*

   * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
   * All Rights Reserved.

   *

   * 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.
   *

   * This program is distributed in the hope that it would 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 the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

   */

  #include "xfs.h"

  #include "xfs_fs.h"

  #include "xfs_types.h"

  #include "xfs_bit.h"

  #include "xfs_log.h"

  #include "xfs_inum.h"

  #include "xfs_trans.h"
  #include "xfs_sb.h"
  #include "xfs_ag.h"

  #include "xfs_mount.h"

  #include "xfs_da_btree.h"

  #include "xfs_bmap_btree.h"

  #include "xfs_dinode.h"
  #include "xfs_inode.h"
  #include "xfs_bmap.h"

  #include "xfs_dir2_format.h"
  #include "xfs_dir2_priv.h"

  #include "xfs_error.h"

  #include "xfs_trace.h"

  
  /*
   * Local function declarations.
   */
  #ifdef DEBUG
  static void xfs_dir2_leaf_check(xfs_inode_t *dp, xfs_dabuf_t *bp);
  #else
  #define	xfs_dir2_leaf_check(dp, bp)
  #endif
  static int xfs_dir2_leaf_lookup_int(xfs_da_args_t *args, xfs_dabuf_t **lbpp,
  				    int *indexp, xfs_dabuf_t **dbpp);

  static void xfs_dir2_leaf_log_bests(struct xfs_trans *tp, struct xfs_dabuf *bp,
  				    int first, int last);

  static void xfs_dir2_leaf_log_tail(struct xfs_trans *tp, struct xfs_dabuf *bp);

  
  /*
   * Convert a block form directory to a leaf form directory.
   */
  int						/* error */
  xfs_dir2_block_to_leaf(
  	xfs_da_args_t		*args,		/* operation arguments */
  	xfs_dabuf_t		*dbp)		/* input block's buffer */
  {

  	__be16			*bestsp;	/* leaf's bestsp entries */

  	xfs_dablk_t		blkno;		/* leaf block's bno */

  	xfs_dir2_data_hdr_t	*hdr;		/* block header */

  	xfs_dir2_leaf_entry_t	*blp;		/* block's leaf entries */
  	xfs_dir2_block_tail_t	*btp;		/* block's tail */
  	xfs_inode_t		*dp;		/* incore directory inode */
  	int			error;		/* error return code */
  	xfs_dabuf_t		*lbp;		/* leaf block's buffer */
  	xfs_dir2_db_t		ldb;		/* leaf block's bno */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_dir2_leaf_tail_t	*ltp;		/* leaf's tail */
  	xfs_mount_t		*mp;		/* filesystem mount point */
  	int			needlog;	/* need to log block header */
  	int			needscan;	/* need to rescan bestfree */
  	xfs_trans_t		*tp;		/* transaction pointer */

  	trace_xfs_dir2_block_to_leaf(args);

  	dp = args->dp;
  	mp = dp->i_mount;
  	tp = args->trans;
  	/*
  	 * Add the leaf block to the inode.
  	 * This interface will only put blocks in the leaf/node range.
  	 * Since that's empty now, we'll get the root (block 0 in range).
  	 */
  	if ((error = xfs_da_grow_inode(args, &blkno))) {
  		return error;
  	}

  	ldb = xfs_dir2_da_to_db(mp, blkno);

  	ASSERT(ldb == XFS_DIR2_LEAF_FIRSTDB(mp));
  	/*
  	 * Initialize the leaf block, get a buffer for it.
  	 */
  	if ((error = xfs_dir2_leaf_init(args, ldb, &lbp, XFS_DIR2_LEAF1_MAGIC))) {
  		return error;
  	}
  	ASSERT(lbp != NULL);
  	leaf = lbp->data;

  	hdr = dbp->data;

  	xfs_dir2_data_check(dp, dbp);

  	btp = xfs_dir2_block_tail_p(mp, hdr);

  	blp = xfs_dir2_block_leaf_p(btp);

  	/*
  	 * Set the counts in the leaf header.
  	 */

  	leaf->hdr.count = cpu_to_be16(be32_to_cpu(btp->count));
  	leaf->hdr.stale = cpu_to_be16(be32_to_cpu(btp->stale));

  	/*
  	 * Could compact these but I think we always do the conversion
  	 * after squeezing out stale entries.
  	 */

  	memcpy(leaf->ents, blp, be32_to_cpu(btp->count) * sizeof(xfs_dir2_leaf_entry_t));

  	xfs_dir2_leaf_log_ents(tp, lbp, 0, be16_to_cpu(leaf->hdr.count) - 1);

  	needscan = 0;
  	needlog = 1;
  	/*
  	 * Make the space formerly occupied by the leaf entries and block
  	 * tail be free.
  	 */
  	xfs_dir2_data_make_free(tp, dbp,

  		(xfs_dir2_data_aoff_t)((char *)blp - (char *)hdr),
  		(xfs_dir2_data_aoff_t)((char *)hdr + mp->m_dirblksize -

  				       (char *)blp),
  		&needlog, &needscan);
  	/*
  	 * Fix up the block header, make it a data block.
  	 */

  	hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);

  	if (needscan)

  		xfs_dir2_data_freescan(mp, hdr, &needlog);

  	/*
  	 * Set up leaf tail and bests table.
  	 */

  	ltp = xfs_dir2_leaf_tail_p(mp, leaf);

  	ltp->bestcount = cpu_to_be32(1);

  	bestsp = xfs_dir2_leaf_bests_p(ltp);

  	bestsp[0] =  hdr->bestfree[0].length;

  	/*
  	 * Log the data header and leaf bests table.
  	 */
  	if (needlog)
  		xfs_dir2_data_log_header(tp, dbp);
  	xfs_dir2_leaf_check(dp, lbp);
  	xfs_dir2_data_check(dp, dbp);
  	xfs_dir2_leaf_log_bests(tp, lbp, 0, 0);
  	xfs_da_buf_done(lbp);
  	return 0;
  }

  STATIC void
  xfs_dir2_leaf_find_stale(
  	struct xfs_dir2_leaf	*leaf,
  	int			index,
  	int			*lowstale,
  	int			*highstale)
  {
  	/*
  	 * Find the first stale entry before our index, if any.
  	 */
  	for (*lowstale = index - 1; *lowstale >= 0; --*lowstale) {
  		if (leaf->ents[*lowstale].address ==
  		    cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
  			break;
  	}
  
  	/*
  	 * Find the first stale entry at or after our index, if any.
  	 * Stop if the result would require moving more entries than using
  	 * lowstale.
  	 */
  	for (*highstale = index;
  	     *highstale < be16_to_cpu(leaf->hdr.count);
  	     ++*highstale) {
  		if (leaf->ents[*highstale].address ==
  		    cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
  			break;
  		if (*lowstale >= 0 && index - *lowstale <= *highstale - index)
  			break;
  	}
  }

  struct xfs_dir2_leaf_entry *
  xfs_dir2_leaf_find_entry(
  	xfs_dir2_leaf_t		*leaf,		/* leaf structure */
  	int			index,		/* leaf table position */
  	int			compact,	/* need to compact leaves */
  	int			lowstale,	/* index of prev stale leaf */
  	int			highstale,	/* index of next stale leaf */
  	int			*lfloglow,	/* low leaf logging index */
  	int			*lfloghigh)	/* high leaf logging index */
  {
  	if (!leaf->hdr.stale) {
  		xfs_dir2_leaf_entry_t	*lep;	/* leaf entry table pointer */
  
  		/*
  		 * Now we need to make room to insert the leaf entry.
  		 *
  		 * If there are no stale entries, just insert a hole at index.
  		 */
  		lep = &leaf->ents[index];
  		if (index < be16_to_cpu(leaf->hdr.count))
  			memmove(lep + 1, lep,
  				(be16_to_cpu(leaf->hdr.count) - index) *
  				 sizeof(*lep));
  
  		/*
  		 * Record low and high logging indices for the leaf.
  		 */
  		*lfloglow = index;
  		*lfloghigh = be16_to_cpu(leaf->hdr.count);
  		be16_add_cpu(&leaf->hdr.count, 1);
  		return lep;
  	}
  
  	/*
  	 * There are stale entries.
  	 *
  	 * We will use one of them for the new entry.  It's probably not at
  	 * the right location, so we'll have to shift some up or down first.
  	 *
  	 * If we didn't compact before, we need to find the nearest stale
  	 * entries before and after our insertion point.
  	 */

  	if (compact == 0)
  		xfs_dir2_leaf_find_stale(leaf, index, &lowstale, &highstale);

  
  	/*
  	 * If the low one is better, use it.
  	 */
  	if (lowstale >= 0 &&
  	    (highstale == be16_to_cpu(leaf->hdr.count) ||
  	     index - lowstale - 1 < highstale - index)) {
  		ASSERT(index - lowstale - 1 >= 0);

  		ASSERT(leaf->ents[lowstale].address ==
  		       cpu_to_be32(XFS_DIR2_NULL_DATAPTR));

  
  		/*
  		 * Copy entries up to cover the stale entry and make room
  		 * for the new entry.
  		 */
  		if (index - lowstale - 1 > 0) {
  			memmove(&leaf->ents[lowstale],
  				&leaf->ents[lowstale + 1],
  				(index - lowstale - 1) *
  				sizeof(xfs_dir2_leaf_entry_t));
  		}
  		*lfloglow = MIN(lowstale, *lfloglow);
  		*lfloghigh = MAX(index - 1, *lfloghigh);
  		be16_add_cpu(&leaf->hdr.stale, -1);
  		return &leaf->ents[index - 1];
  	}
  
  	/*
  	 * The high one is better, so use that one.
  	 */
  	ASSERT(highstale - index >= 0);

  	ASSERT(leaf->ents[highstale].address ==
  	       cpu_to_be32(XFS_DIR2_NULL_DATAPTR));

  
  	/*
  	 * Copy entries down to cover the stale entry and make room for the
  	 * new entry.
  	 */
  	if (highstale - index > 0) {
  		memmove(&leaf->ents[index + 1],
  			&leaf->ents[index],
  			(highstale - index) * sizeof(xfs_dir2_leaf_entry_t));
  	}
  	*lfloglow = MIN(index, *lfloglow);
  	*lfloghigh = MAX(highstale, *lfloghigh);
  	be16_add_cpu(&leaf->hdr.stale, -1);
  	return &leaf->ents[index];
  }

  /*
   * Add an entry to a leaf form directory.
   */
  int						/* error */
  xfs_dir2_leaf_addname(
  	xfs_da_args_t		*args)		/* operation arguments */
  {

  	__be16			*bestsp;	/* freespace table in leaf */

  	int			compact;	/* need to compact leaves */

  	xfs_dir2_data_hdr_t	*hdr;		/* data block header */

  	xfs_dabuf_t		*dbp;		/* data block buffer */
  	xfs_dir2_data_entry_t	*dep;		/* data block entry */
  	xfs_inode_t		*dp;		/* incore directory inode */
  	xfs_dir2_data_unused_t	*dup;		/* data unused entry */
  	int			error;		/* error return value */
  	int			grown;		/* allocated new data block */
  	int			highstale;	/* index of next stale leaf */
  	int			i;		/* temporary, index */
  	int			index;		/* leaf table position */
  	xfs_dabuf_t		*lbp;		/* leaf's buffer */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	int			length;		/* length of new entry */
  	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry table pointer */
  	int			lfloglow;	/* low leaf logging index */
  	int			lfloghigh;	/* high leaf logging index */
  	int			lowstale;	/* index of prev stale leaf */
  	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail pointer */
  	xfs_mount_t		*mp;		/* filesystem mount point */
  	int			needbytes;	/* leaf block bytes needed */
  	int			needlog;	/* need to log data header */
  	int			needscan;	/* need to rescan data free */

  	__be16			*tagp;		/* end of data entry */

  	xfs_trans_t		*tp;		/* transaction pointer */
  	xfs_dir2_db_t		use_block;	/* data block number */

  	trace_xfs_dir2_leaf_addname(args);

  	dp = args->dp;
  	tp = args->trans;
  	mp = dp->i_mount;
  	/*
  	 * Read the leaf block.
  	 */
  	error = xfs_da_read_buf(tp, dp, mp->m_dirleafblk, -1, &lbp,
  		XFS_DATA_FORK);
  	if (error) {
  		return error;
  	}
  	ASSERT(lbp != NULL);
  	/*
  	 * Look up the entry by hash value and name.
  	 * We know it's not there, our caller has already done a lookup.
  	 * So the index is of the entry to insert in front of.
  	 * But if there are dup hash values the index is of the first of those.
  	 */
  	index = xfs_dir2_leaf_search_hash(args, lbp);
  	leaf = lbp->data;

  	ltp = xfs_dir2_leaf_tail_p(mp, leaf);
  	bestsp = xfs_dir2_leaf_bests_p(ltp);
  	length = xfs_dir2_data_entsize(args->namelen);

  	/*
  	 * See if there are any entries with the same hash value
  	 * and space in their block for the new entry.
  	 * This is good because it puts multiple same-hash value entries
  	 * in a data block, improving the lookup of those entries.
  	 */
  	for (use_block = -1, lep = &leaf->ents[index];

  	     index < be16_to_cpu(leaf->hdr.count) && be32_to_cpu(lep->hashval) == args->hashval;

  	     index++, lep++) {

  		if (be32_to_cpu(lep->address) == XFS_DIR2_NULL_DATAPTR)

  			continue;

  		i = xfs_dir2_dataptr_to_db(mp, be32_to_cpu(lep->address));

  		ASSERT(i < be32_to_cpu(ltp->bestcount));

  		ASSERT(bestsp[i] != cpu_to_be16(NULLDATAOFF));

  		if (be16_to_cpu(bestsp[i]) >= length) {

  			use_block = i;
  			break;
  		}
  	}
  	/*
  	 * Didn't find a block yet, linear search all the data blocks.
  	 */
  	if (use_block == -1) {

  		for (i = 0; i < be32_to_cpu(ltp->bestcount); i++) {

  			/*
  			 * Remember a block we see that's missing.
  			 */

  			if (bestsp[i] == cpu_to_be16(NULLDATAOFF) &&
  			    use_block == -1)

  				use_block = i;

  			else if (be16_to_cpu(bestsp[i]) >= length) {

  				use_block = i;
  				break;
  			}
  		}
  	}
  	/*
  	 * How many bytes do we need in the leaf block?
  	 */

  	needbytes = 0;
  	if (!leaf->hdr.stale)
  		needbytes += sizeof(xfs_dir2_leaf_entry_t);
  	if (use_block == -1)
  		needbytes += sizeof(xfs_dir2_data_off_t);

  	/*
  	 * Now kill use_block if it refers to a missing block, so we
  	 * can use it as an indication of allocation needed.
  	 */

  	if (use_block != -1 && bestsp[use_block] == cpu_to_be16(NULLDATAOFF))

  		use_block = -1;
  	/*
  	 * If we don't have enough free bytes but we can make enough
  	 * by compacting out stale entries, we'll do that.
  	 */

  	if ((char *)bestsp - (char *)&leaf->ents[be16_to_cpu(leaf->hdr.count)] <
  				needbytes && be16_to_cpu(leaf->hdr.stale) > 1) {

  		compact = 1;
  	}
  	/*
  	 * Otherwise if we don't have enough free bytes we need to
  	 * convert to node form.
  	 */

  	else if ((char *)bestsp - (char *)&leaf->ents[be16_to_cpu(
  						leaf->hdr.count)] < needbytes) {

  		/*
  		 * Just checking or no space reservation, give up.
  		 */

  		if ((args->op_flags & XFS_DA_OP_JUSTCHECK) ||
  							args->total == 0) {

  			xfs_da_brelse(tp, lbp);
  			return XFS_ERROR(ENOSPC);
  		}
  		/*
  		 * Convert to node form.
  		 */
  		error = xfs_dir2_leaf_to_node(args, lbp);
  		xfs_da_buf_done(lbp);
  		if (error)
  			return error;
  		/*
  		 * Then add the new entry.
  		 */
  		return xfs_dir2_node_addname(args);
  	}
  	/*
  	 * Otherwise it will fit without compaction.
  	 */
  	else
  		compact = 0;
  	/*
  	 * If just checking, then it will fit unless we needed to allocate
  	 * a new data block.
  	 */

  	if (args->op_flags & XFS_DA_OP_JUSTCHECK) {

  		xfs_da_brelse(tp, lbp);
  		return use_block == -1 ? XFS_ERROR(ENOSPC) : 0;
  	}
  	/*
  	 * If no allocations are allowed, return now before we've
  	 * changed anything.
  	 */
  	if (args->total == 0 && use_block == -1) {
  		xfs_da_brelse(tp, lbp);
  		return XFS_ERROR(ENOSPC);
  	}
  	/*
  	 * Need to compact the leaf entries, removing stale ones.
  	 * Leave one stale entry behind - the one closest to our
  	 * insertion index - and we'll shift that one to our insertion
  	 * point later.
  	 */
  	if (compact) {
  		xfs_dir2_leaf_compact_x1(lbp, &index, &lowstale, &highstale,
  			&lfloglow, &lfloghigh);
  	}
  	/*
  	 * There are stale entries, so we'll need log-low and log-high
  	 * impossibly bad values later.
  	 */

  	else if (be16_to_cpu(leaf->hdr.stale)) {
  		lfloglow = be16_to_cpu(leaf->hdr.count);

  		lfloghigh = -1;
  	}
  	/*
  	 * If there was no data block space found, we need to allocate
  	 * a new one.
  	 */
  	if (use_block == -1) {
  		/*
  		 * Add the new data block.
  		 */
  		if ((error = xfs_dir2_grow_inode(args, XFS_DIR2_DATA_SPACE,
  				&use_block))) {
  			xfs_da_brelse(tp, lbp);
  			return error;
  		}
  		/*
  		 * Initialize the block.
  		 */
  		if ((error = xfs_dir2_data_init(args, use_block, &dbp))) {
  			xfs_da_brelse(tp, lbp);
  			return error;
  		}
  		/*
  		 * If we're adding a new data block on the end we need to
  		 * extend the bests table.  Copy it up one entry.
  		 */

  		if (use_block >= be32_to_cpu(ltp->bestcount)) {

  			bestsp--;
  			memmove(&bestsp[0], &bestsp[1],

  				be32_to_cpu(ltp->bestcount) * sizeof(bestsp[0]));

  			be32_add_cpu(&ltp->bestcount, 1);

  			xfs_dir2_leaf_log_tail(tp, lbp);

  			xfs_dir2_leaf_log_bests(tp, lbp, 0, be32_to_cpu(ltp->bestcount) - 1);

  		}
  		/*
  		 * If we're filling in a previously empty block just log it.
  		 */
  		else
  			xfs_dir2_leaf_log_bests(tp, lbp, use_block, use_block);

  		hdr = dbp->data;
  		bestsp[use_block] = hdr->bestfree[0].length;

  		grown = 1;
  	}
  	/*
  	 * Already had space in some data block.
  	 * Just read that one in.
  	 */
  	else {
  		if ((error =

  		    xfs_da_read_buf(tp, dp, xfs_dir2_db_to_da(mp, use_block),

  			    -1, &dbp, XFS_DATA_FORK))) {
  			xfs_da_brelse(tp, lbp);
  			return error;
  		}

  		hdr = dbp->data;

  		grown = 0;
  	}
  	xfs_dir2_data_check(dp, dbp);
  	/*
  	 * Point to the biggest freespace in our data block.
  	 */
  	dup = (xfs_dir2_data_unused_t *)

  	      ((char *)hdr + be16_to_cpu(hdr->bestfree[0].offset));

  	ASSERT(be16_to_cpu(dup->length) >= length);

  	needscan = needlog = 0;
  	/*
  	 * Mark the initial part of our freespace in use for the new entry.
  	 */
  	xfs_dir2_data_use_free(tp, dbp, dup,

  		(xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr), length,

  		&needlog, &needscan);
  	/*
  	 * Initialize our new entry (at last).
  	 */
  	dep = (xfs_dir2_data_entry_t *)dup;

  	dep->inumber = cpu_to_be64(args->inumber);

  	dep->namelen = args->namelen;
  	memcpy(dep->name, args->name, dep->namelen);

  	tagp = xfs_dir2_data_entry_tag_p(dep);

  	*tagp = cpu_to_be16((char *)dep - (char *)hdr);

  	/*
  	 * Need to scan fix up the bestfree table.
  	 */
  	if (needscan)

  		xfs_dir2_data_freescan(mp, hdr, &needlog);

  	/*
  	 * Need to log the data block's header.
  	 */
  	if (needlog)
  		xfs_dir2_data_log_header(tp, dbp);
  	xfs_dir2_data_log_entry(tp, dbp, dep);
  	/*
  	 * If the bests table needs to be changed, do it.
  	 * Log the change unless we've already done that.
  	 */

  	if (be16_to_cpu(bestsp[use_block]) != be16_to_cpu(hdr->bestfree[0].length)) {
  		bestsp[use_block] = hdr->bestfree[0].length;

  		if (!grown)
  			xfs_dir2_leaf_log_bests(tp, lbp, use_block, use_block);
  	}

  
  	lep = xfs_dir2_leaf_find_entry(leaf, index, compact, lowstale,
  				       highstale, &lfloglow, &lfloghigh);

  	/*
  	 * Fill in the new leaf entry.
  	 */

  	lep->hashval = cpu_to_be32(args->hashval);

  	lep->address = cpu_to_be32(xfs_dir2_db_off_to_dataptr(mp, use_block,

  				be16_to_cpu(*tagp)));

  	/*
  	 * Log the leaf fields and give up the buffers.
  	 */
  	xfs_dir2_leaf_log_header(tp, lbp);
  	xfs_dir2_leaf_log_ents(tp, lbp, lfloglow, lfloghigh);
  	xfs_dir2_leaf_check(dp, lbp);
  	xfs_da_buf_done(lbp);
  	xfs_dir2_data_check(dp, dbp);
  	xfs_da_buf_done(dbp);
  	return 0;
  }
  
  #ifdef DEBUG
  /*
   * Check the internal consistency of a leaf1 block.
   * Pop an assert if something is wrong.
   */

  STATIC void

  xfs_dir2_leaf_check(
  	xfs_inode_t		*dp,		/* incore directory inode */
  	xfs_dabuf_t		*bp)		/* leaf's buffer */
  {
  	int			i;		/* leaf index */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail pointer */
  	xfs_mount_t		*mp;		/* filesystem mount point */
  	int			stale;		/* count of stale leaves */
  
  	leaf = bp->data;
  	mp = dp->i_mount;

  	ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAF1_MAGIC));

  	/*
  	 * This value is not restrictive enough.
  	 * Should factor in the size of the bests table as well.
  	 * We can deduce a value for that from di_size.
  	 */

  	ASSERT(be16_to_cpu(leaf->hdr.count) <= xfs_dir2_max_leaf_ents(mp));
  	ltp = xfs_dir2_leaf_tail_p(mp, leaf);

  	/*
  	 * Leaves and bests don't overlap.
  	 */

  	ASSERT((char *)&leaf->ents[be16_to_cpu(leaf->hdr.count)] <=

  	       (char *)xfs_dir2_leaf_bests_p(ltp));

  	/*
  	 * Check hash value order, count stale entries.
  	 */

  	for (i = stale = 0; i < be16_to_cpu(leaf->hdr.count); i++) {
  		if (i + 1 < be16_to_cpu(leaf->hdr.count))

  			ASSERT(be32_to_cpu(leaf->ents[i].hashval) <=
  			       be32_to_cpu(leaf->ents[i + 1].hashval));

  		if (leaf->ents[i].address == cpu_to_be32(XFS_DIR2_NULL_DATAPTR))

  			stale++;
  	}

  	ASSERT(be16_to_cpu(leaf->hdr.stale) == stale);

  }
  #endif	/* DEBUG */
  
  /*
   * Compact out any stale entries in the leaf.
   * Log the header and changed leaf entries, if any.
   */
  void
  xfs_dir2_leaf_compact(
  	xfs_da_args_t	*args,		/* operation arguments */
  	xfs_dabuf_t	*bp)		/* leaf buffer */
  {
  	int		from;		/* source leaf index */
  	xfs_dir2_leaf_t	*leaf;		/* leaf structure */
  	int		loglow;		/* first leaf entry to log */
  	int		to;		/* target leaf index */
  
  	leaf = bp->data;
  	if (!leaf->hdr.stale) {
  		return;
  	}
  	/*
  	 * Compress out the stale entries in place.
  	 */

  	for (from = to = 0, loglow = -1; from < be16_to_cpu(leaf->hdr.count); from++) {

  		if (leaf->ents[from].address ==
  		    cpu_to_be32(XFS_DIR2_NULL_DATAPTR))

  			continue;
  		/*
  		 * Only actually copy the entries that are different.
  		 */
  		if (from > to) {
  			if (loglow == -1)
  				loglow = to;
  			leaf->ents[to] = leaf->ents[from];
  		}
  		to++;
  	}
  	/*
  	 * Update and log the header, log the leaf entries.
  	 */

  	ASSERT(be16_to_cpu(leaf->hdr.stale) == from - to);

  	be16_add_cpu(&leaf->hdr.count, -(be16_to_cpu(leaf->hdr.stale)));

  	leaf->hdr.stale = 0;
  	xfs_dir2_leaf_log_header(args->trans, bp);
  	if (loglow != -1)
  		xfs_dir2_leaf_log_ents(args->trans, bp, loglow, to - 1);
  }
  
  /*
   * Compact the leaf entries, removing stale ones.
   * Leave one stale entry behind - the one closest to our
   * insertion index - and the caller will shift that one to our insertion
   * point later.
   * Return new insertion index, where the remaining stale entry is,
   * and leaf logging indices.
   */
  void
  xfs_dir2_leaf_compact_x1(
  	xfs_dabuf_t	*bp,		/* leaf buffer */
  	int		*indexp,	/* insertion index */
  	int		*lowstalep,	/* out: stale entry before us */
  	int		*highstalep,	/* out: stale entry after us */
  	int		*lowlogp,	/* out: low log index */
  	int		*highlogp)	/* out: high log index */
  {
  	int		from;		/* source copy index */
  	int		highstale;	/* stale entry at/after index */
  	int		index;		/* insertion index */
  	int		keepstale;	/* source index of kept stale */
  	xfs_dir2_leaf_t	*leaf;		/* leaf structure */
  	int		lowstale;	/* stale entry before index */
  	int		newindex=0;	/* new insertion index */
  	int		to;		/* destination copy index */
  
  	leaf = bp->data;

  	ASSERT(be16_to_cpu(leaf->hdr.stale) > 1);

  	index = *indexp;

  
  	xfs_dir2_leaf_find_stale(leaf, index, &lowstale, &highstale);

  	/*
  	 * Pick the better of lowstale and highstale.
  	 */
  	if (lowstale >= 0 &&

  	    (highstale == be16_to_cpu(leaf->hdr.count) ||

  	     index - lowstale <= highstale - index))
  		keepstale = lowstale;
  	else
  		keepstale = highstale;
  	/*
  	 * Copy the entries in place, removing all the stale entries
  	 * except keepstale.
  	 */

  	for (from = to = 0; from < be16_to_cpu(leaf->hdr.count); from++) {

  		/*
  		 * Notice the new value of index.
  		 */
  		if (index == from)
  			newindex = to;
  		if (from != keepstale &&

  		    leaf->ents[from].address ==
  		    cpu_to_be32(XFS_DIR2_NULL_DATAPTR)) {

  			if (from == to)
  				*lowlogp = to;
  			continue;
  		}
  		/*
  		 * Record the new keepstale value for the insertion.
  		 */
  		if (from == keepstale)
  			lowstale = highstale = to;
  		/*
  		 * Copy only the entries that have moved.
  		 */
  		if (from > to)
  			leaf->ents[to] = leaf->ents[from];
  		to++;
  	}
  	ASSERT(from > to);
  	/*
  	 * If the insertion point was past the last entry,
  	 * set the new insertion point accordingly.
  	 */
  	if (index == from)
  		newindex = to;
  	*indexp = newindex;
  	/*
  	 * Adjust the leaf header values.
  	 */

  	be16_add_cpu(&leaf->hdr.count, -(from - to));

  	leaf->hdr.stale = cpu_to_be16(1);

  	/*
  	 * Remember the low/high stale value only in the "right"
  	 * direction.
  	 */
  	if (lowstale >= newindex)
  		lowstale = -1;
  	else

  		highstale = be16_to_cpu(leaf->hdr.count);
  	*highlogp = be16_to_cpu(leaf->hdr.count) - 1;

  	*lowstalep = lowstale;
  	*highstalep = highstale;
  }
  
  /*
   * Getdents (readdir) for leaf and node directories.
   * This reads the data blocks only, so is the same for both forms.
   */
  int						/* error */
  xfs_dir2_leaf_getdents(

  	xfs_inode_t		*dp,		/* incore directory inode */

  	void			*dirent,
  	size_t			bufsize,
  	xfs_off_t		*offset,
  	filldir_t		filldir)

  {
  	xfs_dabuf_t		*bp;		/* data block buffer */
  	int			byteoff;	/* offset in current block */
  	xfs_dir2_db_t		curdb;		/* db for current block */
  	xfs_dir2_off_t		curoff;		/* current overall offset */

  	xfs_dir2_data_hdr_t	*hdr;		/* data block header */

  	xfs_dir2_data_entry_t	*dep;		/* data entry */
  	xfs_dir2_data_unused_t	*dup;		/* unused entry */

  	int			error = 0;	/* error return value */

  	int			i;		/* temporary loop index */
  	int			j;		/* temporary loop index */
  	int			length;		/* temporary length value */
  	xfs_bmbt_irec_t		*map;		/* map vector for blocks */
  	xfs_extlen_t		map_blocks;	/* number of fsbs in map */
  	xfs_dablk_t		map_off;	/* last mapped file offset */
  	int			map_size;	/* total entries in *map */
  	int			map_valid;	/* valid entries in *map */
  	xfs_mount_t		*mp;		/* filesystem mount point */
  	xfs_dir2_off_t		newoff;		/* new curoff after new blk */
  	int			nmap;		/* mappings to ask xfs_bmapi */

  	char			*ptr = NULL;	/* pointer to current data */

  	int			ra_current;	/* number of read-ahead blks */
  	int			ra_index;	/* *map index for read-ahead */
  	int			ra_offset;	/* map entry offset for ra */
  	int			ra_want;	/* readahead count wanted */
  
  	/*
  	 * If the offset is at or past the largest allowed value,

  	 * give up right away.

  	 */

  	if (*offset >= XFS_DIR2_MAX_DATAPTR)

  		return 0;

  	mp = dp->i_mount;

  	/*
  	 * Set up to bmap a number of blocks based on the caller's
  	 * buffer size, the directory block size, and the filesystem
  	 * block size.
  	 */

  	map_size = howmany(bufsize + mp->m_dirblksize, mp->m_sb.sb_blocksize);

  	map = kmem_alloc(map_size * sizeof(*map), KM_SLEEP);
  	map_valid = ra_index = ra_offset = ra_current = map_blocks = 0;
  	bp = NULL;

  	/*
  	 * Inside the loop we keep the main offset value as a byte offset
  	 * in the directory file.
  	 */

  	curoff = xfs_dir2_dataptr_to_byte(mp, *offset);

  	/*
  	 * Force this conversion through db so we truncate the offset
  	 * down to get the start of the data block.
  	 */

  	map_off = xfs_dir2_db_to_da(mp, xfs_dir2_byte_to_db(mp, curoff));

  	/*
  	 * Loop over directory entries until we reach the end offset.
  	 * Get more blocks and readahead as necessary.
  	 */
  	while (curoff < XFS_DIR2_LEAF_OFFSET) {
  		/*
  		 * If we have no buffer, or we're off the end of the
  		 * current buffer, need to get another one.
  		 */
  		if (!bp || ptr >= (char *)bp->data + mp->m_dirblksize) {
  			/*
  			 * If we have a buffer, we need to release it and
  			 * take it out of the mapping.
  			 */
  			if (bp) {

  				xfs_da_brelse(NULL, bp);

  				bp = NULL;
  				map_blocks -= mp->m_dirblkfsbs;
  				/*
  				 * Loop to get rid of the extents for the
  				 * directory block.
  				 */
  				for (i = mp->m_dirblkfsbs; i > 0; ) {
  					j = MIN((int)map->br_blockcount, i);
  					map->br_blockcount -= j;
  					map->br_startblock += j;
  					map->br_startoff += j;
  					/*
  					 * If mapping is done, pitch it from
  					 * the table.
  					 */
  					if (!map->br_blockcount && --map_valid)
  						memmove(&map[0], &map[1],
  							sizeof(map[0]) *
  							map_valid);
  					i -= j;
  				}
  			}
  			/*
  			 * Recalculate the readahead blocks wanted.
  			 */

  			ra_want = howmany(bufsize + mp->m_dirblksize,

  					  mp->m_sb.sb_blocksize) - 1;

  			ASSERT(ra_want >= 0);

  			/*
  			 * If we don't have as many as we want, and we haven't
  			 * run out of data blocks, get some more mappings.
  			 */
  			if (1 + ra_want > map_blocks &&
  			    map_off <

  			    xfs_dir2_byte_to_da(mp, XFS_DIR2_LEAF_OFFSET)) {

  				/*
  				 * Get more bmaps, fill in after the ones
  				 * we already have in the table.
  				 */
  				nmap = map_size - map_valid;

  				error = xfs_bmapi_read(dp, map_off,

  					xfs_dir2_byte_to_da(mp,

  						XFS_DIR2_LEAF_OFFSET) - map_off,

  					&map[map_valid], &nmap, 0);

  				/*
  				 * Don't know if we should ignore this or
  				 * try to return an error.
  				 * The trouble with returning errors
  				 * is that readdir will just stop without
  				 * actually passing the error through.
  				 */
  				if (error)
  					break;	/* XXX */
  				/*
  				 * If we got all the mappings we asked for,
  				 * set the final map offset based on the
  				 * last bmap value received.
  				 * Otherwise, we've reached the end.
  				 */
  				if (nmap == map_size - map_valid)
  					map_off =
  					map[map_valid + nmap - 1].br_startoff +
  					map[map_valid + nmap - 1].br_blockcount;
  				else
  					map_off =

  						xfs_dir2_byte_to_da(mp,

  							XFS_DIR2_LEAF_OFFSET);
  				/*
  				 * Look for holes in the mapping, and
  				 * eliminate them.  Count up the valid blocks.
  				 */
  				for (i = map_valid; i < map_valid + nmap; ) {
  					if (map[i].br_startblock ==
  					    HOLESTARTBLOCK) {
  						nmap--;
  						length = map_valid + nmap - i;
  						if (length)
  							memmove(&map[i],
  								&map[i + 1],
  								sizeof(map[i]) *
  								length);
  					} else {
  						map_blocks +=
  							map[i].br_blockcount;
  						i++;
  					}
  				}
  				map_valid += nmap;
  			}
  			/*
  			 * No valid mappings, so no more data blocks.
  			 */
  			if (!map_valid) {

  				curoff = xfs_dir2_da_to_byte(mp, map_off);

  				break;
  			}
  			/*
  			 * Read the directory block starting at the first
  			 * mapping.
  			 */

  			curdb = xfs_dir2_da_to_db(mp, map->br_startoff);

  			error = xfs_da_read_buf(NULL, dp, map->br_startoff,

  				map->br_blockcount >= mp->m_dirblkfsbs ?
  				    XFS_FSB_TO_DADDR(mp, map->br_startblock) :
  				    -1,
  				&bp, XFS_DATA_FORK);
  			/*
  			 * Should just skip over the data block instead
  			 * of giving up.
  			 */
  			if (error)
  				break;	/* XXX */
  			/*
  			 * Adjust the current amount of read-ahead: we just
  			 * read a block that was previously ra.
  			 */
  			if (ra_current)
  				ra_current -= mp->m_dirblkfsbs;
  			/*
  			 * Do we need more readahead?
  			 */
  			for (ra_index = ra_offset = i = 0;
  			     ra_want > ra_current && i < map_blocks;
  			     i += mp->m_dirblkfsbs) {
  				ASSERT(ra_index < map_valid);
  				/*
  				 * Read-ahead a contiguous directory block.
  				 */
  				if (i > ra_current &&
  				    map[ra_index].br_blockcount >=
  				    mp->m_dirblkfsbs) {

  					xfs_buf_readahead(mp->m_ddev_targp,

  						XFS_FSB_TO_DADDR(mp,
  						   map[ra_index].br_startblock +
  						   ra_offset),
  						(int)BTOBB(mp->m_dirblksize));
  					ra_current = i;
  				}
  				/*
  				 * Read-ahead a non-contiguous directory block.
  				 * This doesn't use our mapping, but this
  				 * is a very rare case.
  				 */
  				else if (i > ra_current) {

  					(void)xfs_da_reada_buf(NULL, dp,

  						map[ra_index].br_startoff +
  						ra_offset, XFS_DATA_FORK);
  					ra_current = i;
  				}
  				/*
  				 * Advance offset through the mapping table.
  				 */
  				for (j = 0; j < mp->m_dirblkfsbs; j++) {
  					/*
  					 * The rest of this extent but not
  					 * more than a dir block.
  					 */
  					length = MIN(mp->m_dirblkfsbs,
  						(int)(map[ra_index].br_blockcount -
  						ra_offset));
  					j += length;
  					ra_offset += length;
  					/*
  					 * Advance to the next mapping if
  					 * this one is used up.
  					 */
  					if (ra_offset ==
  					    map[ra_index].br_blockcount) {
  						ra_offset = 0;
  						ra_index++;
  					}
  				}
  			}
  			/*
  			 * Having done a read, we need to set a new offset.
  			 */

  			newoff = xfs_dir2_db_off_to_byte(mp, curdb, 0);

  			/*
  			 * Start of the current block.
  			 */
  			if (curoff < newoff)
  				curoff = newoff;
  			/*
  			 * Make sure we're in the right block.
  			 */
  			else if (curoff > newoff)

  				ASSERT(xfs_dir2_byte_to_db(mp, curoff) ==

  				       curdb);

  			hdr = bp->data;

  			xfs_dir2_data_check(dp, bp);
  			/*
  			 * Find our position in the block.
  			 */

  			ptr = (char *)(hdr + 1);

  			byteoff = xfs_dir2_byte_to_off(mp, curoff);

  			/*
  			 * Skip past the header.
  			 */
  			if (byteoff == 0)

  				curoff += (uint)sizeof(*hdr);

  			/*
  			 * Skip past entries until we reach our offset.
  			 */
  			else {

  				while ((char *)ptr - (char *)hdr < byteoff) {

  					dup = (xfs_dir2_data_unused_t *)ptr;

  					if (be16_to_cpu(dup->freetag)

  						  == XFS_DIR2_DATA_FREE_TAG) {

  						length = be16_to_cpu(dup->length);

  						ptr += length;
  						continue;
  					}
  					dep = (xfs_dir2_data_entry_t *)ptr;
  					length =

  					   xfs_dir2_data_entsize(dep->namelen);

  					ptr += length;
  				}
  				/*
  				 * Now set our real offset.
  				 */
  				curoff =

  					xfs_dir2_db_off_to_byte(mp,
  					    xfs_dir2_byte_to_db(mp, curoff),

  					    (char *)ptr - (char *)hdr);
  				if (ptr >= (char *)hdr + mp->m_dirblksize) {

  					continue;
  				}
  			}
  		}
  		/*
  		 * We have a pointer to an entry.
  		 * Is it a live one?
  		 */
  		dup = (xfs_dir2_data_unused_t *)ptr;
  		/*
  		 * No, it's unused, skip over it.
  		 */

  		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
  			length = be16_to_cpu(dup->length);

  			ptr += length;
  			curoff += length;
  			continue;
  		}

  		dep = (xfs_dir2_data_entry_t *)ptr;

  		length = xfs_dir2_data_entsize(dep->namelen);

  		if (filldir(dirent, (char *)dep->name, dep->namelen,

  			    xfs_dir2_byte_to_dataptr(mp, curoff) & 0x7fffffff,

  			    be64_to_cpu(dep->inumber), DT_UNKNOWN))

  			break;

  		/*
  		 * Advance to next entry in the block.
  		 */
  		ptr += length;
  		curoff += length;

  		/* bufsize may have just been a guess; don't go negative */
  		bufsize = bufsize > length ? bufsize - length : 0;

  	}
  
  	/*
  	 * All done.  Set output offset value to current offset.
  	 */

  	if (curoff > xfs_dir2_dataptr_to_byte(mp, XFS_DIR2_MAX_DATAPTR))

  		*offset = XFS_DIR2_MAX_DATAPTR & 0x7fffffff;

  	else

  		*offset = xfs_dir2_byte_to_dataptr(mp, curoff) & 0x7fffffff;

  	kmem_free(map);

  	if (bp)

  		xfs_da_brelse(NULL, bp);

  	return error;
  }
  
  /*
   * Initialize a new leaf block, leaf1 or leafn magic accepted.
   */
  int
  xfs_dir2_leaf_init(
  	xfs_da_args_t		*args,		/* operation arguments */
  	xfs_dir2_db_t		bno,		/* directory block number */
  	xfs_dabuf_t		**bpp,		/* out: leaf buffer */
  	int			magic)		/* magic number for block */
  {
  	xfs_dabuf_t		*bp;		/* leaf buffer */
  	xfs_inode_t		*dp;		/* incore directory inode */
  	int			error;		/* error return code */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail structure */
  	xfs_mount_t		*mp;		/* filesystem mount point */
  	xfs_trans_t		*tp;		/* transaction pointer */
  
  	dp = args->dp;
  	ASSERT(dp != NULL);
  	tp = args->trans;
  	mp = dp->i_mount;
  	ASSERT(bno >= XFS_DIR2_LEAF_FIRSTDB(mp) &&
  	       bno < XFS_DIR2_FREE_FIRSTDB(mp));
  	/*
  	 * Get the buffer for the block.
  	 */

  	error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(mp, bno), -1, &bp,

  		XFS_DATA_FORK);
  	if (error) {
  		return error;
  	}
  	ASSERT(bp != NULL);
  	leaf = bp->data;
  	/*
  	 * Initialize the header.
  	 */

  	leaf->hdr.info.magic = cpu_to_be16(magic);

  	leaf->hdr.info.forw = 0;
  	leaf->hdr.info.back = 0;
  	leaf->hdr.count = 0;
  	leaf->hdr.stale = 0;
  	xfs_dir2_leaf_log_header(tp, bp);
  	/*
  	 * If it's a leaf-format directory initialize the tail.
  	 * In this case our caller has the real bests table to copy into
  	 * the block.
  	 */
  	if (magic == XFS_DIR2_LEAF1_MAGIC) {

  		ltp = xfs_dir2_leaf_tail_p(mp, leaf);

  		ltp->bestcount = 0;
  		xfs_dir2_leaf_log_tail(tp, bp);
  	}
  	*bpp = bp;
  	return 0;
  }
  
  /*
   * Log the bests entries indicated from a leaf1 block.
   */

  static void

  xfs_dir2_leaf_log_bests(
  	xfs_trans_t		*tp,		/* transaction pointer */
  	xfs_dabuf_t		*bp,		/* leaf buffer */
  	int			first,		/* first entry to log */
  	int			last)		/* last entry to log */
  {

  	__be16			*firstb;	/* pointer to first entry */
  	__be16			*lastb;		/* pointer to last entry */

  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail structure */
  
  	leaf = bp->data;

  	ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAF1_MAGIC));

  	ltp = xfs_dir2_leaf_tail_p(tp->t_mountp, leaf);
  	firstb = xfs_dir2_leaf_bests_p(ltp) + first;
  	lastb = xfs_dir2_leaf_bests_p(ltp) + last;

  	xfs_da_log_buf(tp, bp, (uint)((char *)firstb - (char *)leaf),
  		(uint)((char *)lastb - (char *)leaf + sizeof(*lastb) - 1));
  }
  
  /*
   * Log the leaf entries indicated from a leaf1 or leafn block.
   */
  void
  xfs_dir2_leaf_log_ents(
  	xfs_trans_t		*tp,		/* transaction pointer */
  	xfs_dabuf_t		*bp,		/* leaf buffer */
  	int			first,		/* first entry to log */
  	int			last)		/* last entry to log */
  {
  	xfs_dir2_leaf_entry_t	*firstlep;	/* pointer to first entry */
  	xfs_dir2_leaf_entry_t	*lastlep;	/* pointer to last entry */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  
  	leaf = bp->data;

  	ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAF1_MAGIC) ||
  	       leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));

  	firstlep = &leaf->ents[first];
  	lastlep = &leaf->ents[last];
  	xfs_da_log_buf(tp, bp, (uint)((char *)firstlep - (char *)leaf),
  		(uint)((char *)lastlep - (char *)leaf + sizeof(*lastlep) - 1));
  }
  
  /*
   * Log the header of the leaf1 or leafn block.
   */
  void
  xfs_dir2_leaf_log_header(
  	xfs_trans_t		*tp,		/* transaction pointer */
  	xfs_dabuf_t		*bp)		/* leaf buffer */
  {
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  
  	leaf = bp->data;

  	ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAF1_MAGIC) ||
  	       leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));

  	xfs_da_log_buf(tp, bp, (uint)((char *)&leaf->hdr - (char *)leaf),
  		(uint)(sizeof(leaf->hdr) - 1));
  }
  
  /*
   * Log the tail of the leaf1 block.
   */

  STATIC void

  xfs_dir2_leaf_log_tail(
  	xfs_trans_t		*tp,		/* transaction pointer */
  	xfs_dabuf_t		*bp)		/* leaf buffer */
  {
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail structure */
  	xfs_mount_t		*mp;		/* filesystem mount point */
  
  	mp = tp->t_mountp;
  	leaf = bp->data;

  	ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAF1_MAGIC));

  	ltp = xfs_dir2_leaf_tail_p(mp, leaf);

  	xfs_da_log_buf(tp, bp, (uint)((char *)ltp - (char *)leaf),
  		(uint)(mp->m_dirblksize - 1));
  }
  
  /*
   * Look up the entry referred to by args in the leaf format directory.
   * Most of the work is done by the xfs_dir2_leaf_lookup_int routine which
   * is also used by the node-format code.
   */
  int
  xfs_dir2_leaf_lookup(
  	xfs_da_args_t		*args)		/* operation arguments */
  {
  	xfs_dabuf_t		*dbp;		/* data block buffer */
  	xfs_dir2_data_entry_t	*dep;		/* data block entry */
  	xfs_inode_t		*dp;		/* incore directory inode */
  	int			error;		/* error return code */
  	int			index;		/* found entry index */
  	xfs_dabuf_t		*lbp;		/* leaf buffer */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry */
  	xfs_trans_t		*tp;		/* transaction pointer */

  	trace_xfs_dir2_leaf_lookup(args);

  	/*
  	 * Look up name in the leaf block, returning both buffers and index.
  	 */
  	if ((error = xfs_dir2_leaf_lookup_int(args, &lbp, &index, &dbp))) {
  		return error;
  	}
  	tp = args->trans;
  	dp = args->dp;
  	xfs_dir2_leaf_check(dp, lbp);
  	leaf = lbp->data;
  	/*
  	 * Get to the leaf entry and contained data entry address.
  	 */
  	lep = &leaf->ents[index];
  	/*
  	 * Point to the data entry.
  	 */
  	dep = (xfs_dir2_data_entry_t *)
  	      ((char *)dbp->data +

  	       xfs_dir2_dataptr_to_off(dp->i_mount, be32_to_cpu(lep->address)));

  	/*

  	 * Return the found inode number & CI name if appropriate

  	 */

  	args->inumber = be64_to_cpu(dep->inumber);

  	error = xfs_dir_cilookup_result(args, dep->name, dep->namelen);

  	xfs_da_brelse(tp, dbp);
  	xfs_da_brelse(tp, lbp);

  	return XFS_ERROR(error);

  }
  
  /*
   * Look up name/hash in the leaf block.
   * Fill in indexp with the found index, and dbpp with the data buffer.
   * If not found dbpp will be NULL, and ENOENT comes back.
   * lbpp will always be filled in with the leaf buffer unless there's an error.
   */
  static int					/* error */
  xfs_dir2_leaf_lookup_int(
  	xfs_da_args_t		*args,		/* operation arguments */
  	xfs_dabuf_t		**lbpp,		/* out: leaf buffer */
  	int			*indexp,	/* out: index in leaf block */
  	xfs_dabuf_t		**dbpp)		/* out: data buffer */
  {

  	xfs_dir2_db_t		curdb = -1;	/* current data block number */
  	xfs_dabuf_t		*dbp = NULL;	/* data buffer */

  	xfs_dir2_data_entry_t	*dep;		/* data entry */
  	xfs_inode_t		*dp;		/* incore directory inode */
  	int			error;		/* error return code */
  	int			index;		/* index in leaf block */
  	xfs_dabuf_t		*lbp;		/* leaf buffer */
  	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_mount_t		*mp;		/* filesystem mount point */
  	xfs_dir2_db_t		newdb;		/* new data block number */
  	xfs_trans_t		*tp;		/* transaction pointer */

  	xfs_dir2_db_t		cidb = -1;	/* case match data block no. */

  	enum xfs_dacmp		cmp;		/* name compare result */

  
  	dp = args->dp;
  	tp = args->trans;
  	mp = dp->i_mount;
  	/*
  	 * Read the leaf block into the buffer.
  	 */

  	error = xfs_da_read_buf(tp, dp, mp->m_dirleafblk, -1, &lbp,
  							XFS_DATA_FORK);
  	if (error)

  		return error;

  	*lbpp = lbp;
  	leaf = lbp->data;
  	xfs_dir2_leaf_check(dp, lbp);
  	/*
  	 * Look for the first leaf entry with our hash value.
  	 */
  	index = xfs_dir2_leaf_search_hash(args, lbp);
  	/*
  	 * Loop over all the entries with the right hash value
  	 * looking to match the name.
  	 */

  	for (lep = &leaf->ents[index]; index < be16_to_cpu(leaf->hdr.count) &&

  				be32_to_cpu(lep->hashval) == args->hashval;
  				lep++, index++) {

  		/*
  		 * Skip over stale leaf entries.
  		 */

  		if (be32_to_cpu(lep->address) == XFS_DIR2_NULL_DATAPTR)

  			continue;
  		/*
  		 * Get the new data block number.
  		 */

  		newdb = xfs_dir2_dataptr_to_db(mp, be32_to_cpu(lep->address));

  		/*
  		 * If it's not the same as the old data block number,
  		 * need to pitch the old one and read the new one.
  		 */
  		if (newdb != curdb) {

  			if (dbp)

  				xfs_da_brelse(tp, dbp);

  			error = xfs_da_read_buf(tp, dp,
  						xfs_dir2_db_to_da(mp, newdb),
  						-1, &dbp, XFS_DATA_FORK);
  			if (error) {

  				xfs_da_brelse(tp, lbp);
  				return error;
  			}
  			xfs_dir2_data_check(dp, dbp);
  			curdb = newdb;
  		}
  		/*
  		 * Point to the data entry.
  		 */

  		dep = (xfs_dir2_data_entry_t *)((char *)dbp->data +
  			xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address)));

  		/*

  		 * Compare name and if it's an exact match, return the index
  		 * and buffer. If it's the first case-insensitive match, store
  		 * the index and buffer and continue looking for an exact match.

  		 */

  		cmp = mp->m_dirnameops->compname(args, dep->name, dep->namelen);
  		if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) {
  			args->cmpresult = cmp;

  			*indexp = index;

  			/* case exact match: return the current buffer. */

  			if (cmp == XFS_CMP_EXACT) {

  				*dbpp = dbp;
  				return 0;
  			}

  			cidb = curdb;

  		}
  	}

  	ASSERT(args->op_flags & XFS_DA_OP_OKNOENT);

  	/*

  	 * Here, we can only be doing a lookup (not a rename or remove).
  	 * If a case-insensitive match was found earlier, re-read the
  	 * appropriate data block if required and return it.

  	 */
  	if (args->cmpresult == XFS_CMP_CASE) {

  		ASSERT(cidb != -1);
  		if (cidb != curdb) {

  			xfs_da_brelse(tp, dbp);

  			error = xfs_da_read_buf(tp, dp,
  						xfs_dir2_db_to_da(mp, cidb),
  						-1, &dbp, XFS_DATA_FORK);
  			if (error) {
  				xfs_da_brelse(tp, lbp);
  				return error;
  			}
  		}
  		*dbpp = dbp;

  		return 0;
  	}

  	/*
  	 * No match found, return ENOENT.
  	 */

  	ASSERT(cidb == -1);

  	if (dbp)
  		xfs_da_brelse(tp, dbp);
  	xfs_da_brelse(tp, lbp);
  	return XFS_ERROR(ENOENT);
  }
  
  /*
   * Remove an entry from a leaf format directory.
   */
  int						/* error */
  xfs_dir2_leaf_removename(
  	xfs_da_args_t		*args)		/* operation arguments */
  {

  	__be16			*bestsp;	/* leaf block best freespace */

  	xfs_dir2_data_hdr_t	*hdr;		/* data block header */

  	xfs_dir2_db_t		db;		/* data block number */
  	xfs_dabuf_t		*dbp;		/* data block buffer */
  	xfs_dir2_data_entry_t	*dep;		/* data entry structure */
  	xfs_inode_t		*dp;		/* incore directory inode */
  	int			error;		/* error return code */
  	xfs_dir2_db_t		i;		/* temporary data block # */
  	int			index;		/* index into leaf entries */
  	xfs_dabuf_t		*lbp;		/* leaf buffer */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry */
  	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail structure */
  	xfs_mount_t		*mp;		/* filesystem mount point */
  	int			needlog;	/* need to log data header */
  	int			needscan;	/* need to rescan data frees */
  	xfs_dir2_data_off_t	oldbest;	/* old value of best free */
  	xfs_trans_t		*tp;		/* transaction pointer */

  	trace_xfs_dir2_leaf_removename(args);

  	/*
  	 * Lookup the leaf entry, get the leaf and data blocks read in.
  	 */
  	if ((error = xfs_dir2_leaf_lookup_int(args, &lbp, &index, &dbp))) {
  		return error;
  	}
  	dp = args->dp;
  	tp = args->trans;
  	mp = dp->i_mount;
  	leaf = lbp->data;

  	hdr = dbp->data;

  	xfs_dir2_data_check(dp, dbp);
  	/*
  	 * Point to the leaf entry, use that to point to the data entry.
  	 */
  	lep = &leaf->ents[index];

  	db = xfs_dir2_dataptr_to_db(mp, be32_to_cpu(lep->address));

  	dep = (xfs_dir2_data_entry_t *)

  	      ((char *)hdr + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address)));

  	needscan = needlog = 0;

  	oldbest = be16_to_cpu(hdr->bestfree[0].length);

  	ltp = xfs_dir2_leaf_tail_p(mp, leaf);
  	bestsp = xfs_dir2_leaf_bests_p(ltp);

  	ASSERT(be16_to_cpu(bestsp[db]) == oldbest);

  	/*
  	 * Mark the former data entry unused.
  	 */
  	xfs_dir2_data_make_free(tp, dbp,

  		(xfs_dir2_data_aoff_t)((char *)dep - (char *)hdr),

  		xfs_dir2_data_entsize(dep->namelen), &needlog, &needscan);

  	/*
  	 * We just mark the leaf entry stale by putting a null in it.
  	 */

  	be16_add_cpu(&leaf->hdr.stale, 1);

  	xfs_dir2_leaf_log_header(tp, lbp);

  	lep->address = cpu_to_be32(XFS_DIR2_NULL_DATAPTR);

  	xfs_dir2_leaf_log_ents(tp, lbp, index, index);
  	/*
  	 * Scan the freespace in the data block again if necessary,
  	 * log the data block header if necessary.
  	 */
  	if (needscan)

  		xfs_dir2_data_freescan(mp, hdr, &needlog);

  	if (needlog)
  		xfs_dir2_data_log_header(tp, dbp);
  	/*
  	 * If the longest freespace in the data block has changed,
  	 * put the new value in the bests table and log that.
  	 */

  	if (be16_to_cpu(hdr->bestfree[0].length) != oldbest) {
  		bestsp[db] = hdr->bestfree[0].length;

  		xfs_dir2_leaf_log_bests(tp, lbp, db, db);
  	}
  	xfs_dir2_data_check(dp, dbp);
  	/*
  	 * If the data block is now empty then get rid of the data block.
  	 */

  	if (be16_to_cpu(hdr->bestfree[0].length) ==
  	    mp->m_dirblksize - (uint)sizeof(*hdr)) {

  		ASSERT(db != mp->m_dirdatablk);
  		if ((error = xfs_dir2_shrink_inode(args, db, dbp))) {
  			/*
  			 * Nope, can't get rid of it because it caused
  			 * allocation of a bmap btree block to do so.
  			 * Just go on, returning success, leaving the
  			 * empty block in place.
  			 */
  			if (error == ENOSPC && args->total == 0) {
  				xfs_da_buf_done(dbp);
  				error = 0;
  			}
  			xfs_dir2_leaf_check(dp, lbp);
  			xfs_da_buf_done(lbp);
  			return error;
  		}
  		dbp = NULL;
  		/*
  		 * If this is the last data block then compact the
  		 * bests table by getting rid of entries.
  		 */

  		if (db == be32_to_cpu(ltp->bestcount) - 1) {

  			/*
  			 * Look for the last active entry (i).
  			 */
  			for (i = db - 1; i > 0; i--) {

  				if (bestsp[i] != cpu_to_be16(NULLDATAOFF))

  					break;
  			}
  			/*
  			 * Copy the table down so inactive entries at the
  			 * end are removed.
  			 */
  			memmove(&bestsp[db - i], bestsp,

  				(be32_to_cpu(ltp->bestcount) - (db - i)) * sizeof(*bestsp));

  			be32_add_cpu(&ltp->bestcount, -(db - i));

  			xfs_dir2_leaf_log_tail(tp, lbp);

  			xfs_dir2_leaf_log_bests(tp, lbp, 0, be32_to_cpu(ltp->bestcount) - 1);

  		} else

  			bestsp[db] = cpu_to_be16(NULLDATAOFF);

  	}
  	/*
  	 * If the data block was not the first one, drop it.
  	 */
  	else if (db != mp->m_dirdatablk && dbp != NULL) {
  		xfs_da_buf_done(dbp);
  		dbp = NULL;
  	}
  	xfs_dir2_leaf_check(dp, lbp);
  	/*
  	 * See if we can convert to block form.
  	 */
  	return xfs_dir2_leaf_to_block(args, lbp, dbp);
  }
  
  /*
   * Replace the inode number in a leaf format directory entry.
   */
  int						/* error */
  xfs_dir2_leaf_replace(
  	xfs_da_args_t		*args)		/* operation arguments */
  {
  	xfs_dabuf_t		*dbp;		/* data block buffer */
  	xfs_dir2_data_entry_t	*dep;		/* data block entry */
  	xfs_inode_t		*dp;		/* incore directory inode */
  	int			error;		/* error return code */
  	int			index;		/* index of leaf entry */
  	xfs_dabuf_t		*lbp;		/* leaf buffer */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry */
  	xfs_trans_t		*tp;		/* transaction pointer */

  	trace_xfs_dir2_leaf_replace(args);

  	/*
  	 * Look up the entry.
  	 */
  	if ((error = xfs_dir2_leaf_lookup_int(args, &lbp, &index, &dbp))) {
  		return error;
  	}
  	dp = args->dp;
  	leaf = lbp->data;
  	/*
  	 * Point to the leaf entry, get data address from it.
  	 */
  	lep = &leaf->ents[index];
  	/*
  	 * Point to the data entry.
  	 */
  	dep = (xfs_dir2_data_entry_t *)
  	      ((char *)dbp->data +

  	       xfs_dir2_dataptr_to_off(dp->i_mount, be32_to_cpu(lep->address)));

  	ASSERT(args->inumber != be64_to_cpu(dep->inumber));

  	/*
  	 * Put the new inode number in, log it.
  	 */

  	dep->inumber = cpu_to_be64(args->inumber);

  	tp = args->trans;
  	xfs_dir2_data_log_entry(tp, dbp, dep);
  	xfs_da_buf_done(dbp);
  	xfs_dir2_leaf_check(dp, lbp);
  	xfs_da_brelse(tp, lbp);
  	return 0;
  }
  
  /*
   * Return index in the leaf block (lbp) which is either the first
   * one with this hash value, or if there are none, the insert point
   * for that hash value.
   */
  int						/* index value */
  xfs_dir2_leaf_search_hash(
  	xfs_da_args_t		*args,		/* operation arguments */
  	xfs_dabuf_t		*lbp)		/* leaf buffer */
  {
  	xfs_dahash_t		hash=0;		/* hash from this entry */
  	xfs_dahash_t		hashwant;	/* hash value looking for */
  	int			high;		/* high leaf index */
  	int			low;		/* low leaf index */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry */
  	int			mid=0;		/* current leaf index */
  
  	leaf = lbp->data;
  #ifndef __KERNEL__
  	if (!leaf->hdr.count)
  		return 0;
  #endif
  	/*
  	 * Note, the table cannot be empty, so we have to go through the loop.
  	 * Binary search the leaf entries looking for our hash value.
  	 */

  	for (lep = leaf->ents, low = 0, high = be16_to_cpu(leaf->hdr.count) - 1,

  		hashwant = args->hashval;
  	     low <= high; ) {
  		mid = (low + high) >> 1;

  		if ((hash = be32_to_cpu(lep[mid].hashval)) == hashwant)

  			break;
  		if (hash < hashwant)
  			low = mid + 1;
  		else
  			high = mid - 1;
  	}
  	/*
  	 * Found one, back up through all the equal hash values.
  	 */
  	if (hash == hashwant) {

  		while (mid > 0 && be32_to_cpu(lep[mid - 1].hashval) == hashwant) {

  			mid--;
  		}
  	}
  	/*
  	 * Need to point to an entry higher than ours.
  	 */
  	else if (hash < hashwant)
  		mid++;
  	return mid;
  }
  
  /*
   * Trim off a trailing data block.  We know it's empty since the leaf
   * freespace table says so.
   */
  int						/* error */
  xfs_dir2_leaf_trim_data(
  	xfs_da_args_t		*args,		/* operation arguments */
  	xfs_dabuf_t		*lbp,		/* leaf buffer */
  	xfs_dir2_db_t		db)		/* data block number */
  {

  	__be16			*bestsp;	/* leaf bests table */

  	xfs_dabuf_t		*dbp;		/* data block buffer */
  	xfs_inode_t		*dp;		/* incore directory inode */
  	int			error;		/* error return value */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail structure */
  	xfs_mount_t		*mp;		/* filesystem mount point */
  	xfs_trans_t		*tp;		/* transaction pointer */
  
  	dp = args->dp;
  	mp = dp->i_mount;
  	tp = args->trans;
  	/*
  	 * Read the offending data block.  We need its buffer.
  	 */

  	if ((error = xfs_da_read_buf(tp, dp, xfs_dir2_db_to_da(mp, db), -1, &dbp,

  			XFS_DATA_FORK))) {
  		return error;
  	}

  
  	leaf = lbp->data;

  	ltp = xfs_dir2_leaf_tail_p(mp, leaf);

  
  #ifdef DEBUG
  {
  	struct xfs_dir2_data_hdr *hdr = dbp->data;

  	ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC));

  	ASSERT(be16_to_cpu(hdr->bestfree[0].length) ==
  	       mp->m_dirblksize - (uint)sizeof(*hdr));

  	ASSERT(db == be32_to_cpu(ltp->bestcount) - 1);

  }
  #endif

  	/*
  	 * Get rid of the data block.
  	 */
  	if ((error = xfs_dir2_shrink_inode(args, db, dbp))) {
  		ASSERT(error != ENOSPC);
  		xfs_da_brelse(tp, dbp);
  		return error;
  	}
  	/*
  	 * Eliminate the last bests entry from the table.
  	 */

  	bestsp = xfs_dir2_leaf_bests_p(ltp);

  	be32_add_cpu(&ltp->bestcount, -1);

  	memmove(&bestsp[1], &bestsp[0], be32_to_cpu(ltp->bestcount) * sizeof(*bestsp));

  	xfs_dir2_leaf_log_tail(tp, lbp);

  	xfs_dir2_leaf_log_bests(tp, lbp, 0, be32_to_cpu(ltp->bestcount) - 1);

  	return 0;
  }

  static inline size_t
  xfs_dir2_leaf_size(
  	struct xfs_dir2_leaf_hdr	*hdr,
  	int				counts)
  {
  	int			entries;
  
  	entries = be16_to_cpu(hdr->count) - be16_to_cpu(hdr->stale);
  	return sizeof(xfs_dir2_leaf_hdr_t) +
  	    entries * sizeof(xfs_dir2_leaf_entry_t) +
  	    counts * sizeof(xfs_dir2_data_off_t) +
  	    sizeof(xfs_dir2_leaf_tail_t);
  }

  /*
   * Convert node form directory to leaf form directory.
   * The root of the node form dir needs to already be a LEAFN block.
   * Just return if we can't do anything.
   */
  int						/* error */
  xfs_dir2_node_to_leaf(
  	xfs_da_state_t		*state)		/* directory operation state */
  {
  	xfs_da_args_t		*args;		/* operation arguments */
  	xfs_inode_t		*dp;		/* incore directory inode */
  	int			error;		/* error return code */
  	xfs_dabuf_t		*fbp;		/* buffer for freespace block */
  	xfs_fileoff_t		fo;		/* freespace file offset */
  	xfs_dir2_free_t		*free;		/* freespace structure */
  	xfs_dabuf_t		*lbp;		/* buffer for leaf block */
  	xfs_dir2_leaf_tail_t	*ltp;		/* tail of leaf structure */
  	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
  	xfs_mount_t		*mp;		/* filesystem mount point */
  	int			rval;		/* successful free trim? */
  	xfs_trans_t		*tp;		/* transaction pointer */
  
  	/*
  	 * There's more than a leaf level in the btree, so there must
  	 * be multiple leafn blocks.  Give up.
  	 */
  	if (state->path.active > 1)
  		return 0;
  	args = state->args;

  
  	trace_xfs_dir2_node_to_leaf(args);

  	mp = state->mp;
  	dp = args->dp;
  	tp = args->trans;
  	/*
  	 * Get the last offset in the file.
  	 */
  	if ((error = xfs_bmap_last_offset(tp, dp, &fo, XFS_DATA_FORK))) {
  		return error;
  	}
  	fo -= mp->m_dirblkfsbs;
  	/*
  	 * If there are freespace blocks other than the first one,
  	 * take this opportunity to remove trailing empty freespace blocks
  	 * that may have been left behind during no-space-reservation
  	 * operations.
  	 */
  	while (fo > mp->m_dirfreeblk) {
  		if ((error = xfs_dir2_node_trim_free(args, fo, &rval))) {
  			return error;
  		}
  		if (rval)
  			fo -= mp->m_dirblkfsbs;
  		else
  			return 0;
  	}
  	/*
  	 * Now find the block just before the freespace block.
  	 */
  	if ((error = xfs_bmap_last_before(tp, dp, &fo, XFS_DATA_FORK))) {
  		return error;
  	}
  	/*
  	 * If it's not the single leaf block, give up.
  	 */
  	if (XFS_FSB_TO_B(mp, fo) > XFS_DIR2_LEAF_OFFSET + mp->m_dirblksize)
  		return 0;
  	lbp = state->path.blk[0].bp;
  	leaf = lbp->data;

  	ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));

  	/*
  	 * Read the freespace block.
  	 */
  	if ((error = xfs_da_read_buf(tp, dp, mp->m_dirfreeblk, -1, &fbp,
  			XFS_DATA_FORK))) {
  		return error;
  	}
  	free = fbp->data;

  	ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC));

  	ASSERT(!free->hdr.firstdb);

  	/*
  	 * Now see if the leafn and free data will fit in a leaf1.
  	 * If not, release the buffer and give up.
  	 */

  	if (xfs_dir2_leaf_size(&leaf->hdr, be32_to_cpu(free->hdr.nvalid)) >
  			mp->m_dirblksize) {

  		xfs_da_brelse(tp, fbp);
  		return 0;
  	}

  	/*
  	 * If the leaf has any stale entries in it, compress them out.
  	 * The compact routine will log the header.
  	 */

  	if (be16_to_cpu(leaf->hdr.stale))

  		xfs_dir2_leaf_compact(args, lbp);
  	else
  		xfs_dir2_leaf_log_header(tp, lbp);

  	leaf->hdr.info.magic = cpu_to_be16(XFS_DIR2_LEAF1_MAGIC);

  	/*
  	 * Set up the leaf tail from the freespace block.
  	 */

  	ltp = xfs_dir2_leaf_tail_p(mp, leaf);

  	ltp->bestcount = free->hdr.nvalid;

  	/*
  	 * Set up the leaf bests table.
  	 */

  	memcpy(xfs_dir2_leaf_bests_p(ltp), free->bests,

  		be32_to_cpu(ltp->bestcount) * sizeof(xfs_dir2_data_off_t));

  	xfs_dir2_leaf_log_bests(tp, lbp, 0, be32_to_cpu(ltp->bestcount) - 1);

  	xfs_dir2_leaf_log_tail(tp, lbp);
  	xfs_dir2_leaf_check(dp, lbp);
  	/*
  	 * Get rid of the freespace block.
  	 */
  	error = xfs_dir2_shrink_inode(args, XFS_DIR2_FREE_FIRSTDB(mp), fbp);
  	if (error) {
  		/*
  		 * This can't fail here because it can only happen when
  		 * punching out the middle of an extent, and this is an
  		 * isolated block.
  		 */
  		ASSERT(error != ENOSPC);
  		return error;
  	}
  	fbp = NULL;
  	/*
  	 * Now see if we can convert the single-leaf directory
  	 * down to a block form directory.
  	 * This routine always kills the dabuf for the leaf, so
  	 * eliminate it from the path.
  	 */
  	error = xfs_dir2_leaf_to_block(args, lbp, NULL);
  	state->path.blk[0].bp = NULL;
  	return error;
  }