[thirdparty/xfsprogs-dev.git] / libxfs / xfs_dir2_leaf.c

/*
 * Copyright (c) 2000-2002 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 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.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */

/*
 * xfs_dir2_leaf.c
 * XFS directory version 2 implementation - single leaf form
 * see xfs_dir2_leaf.h for data structures.
 * These directories have multiple XFS_DIR2_DATA blocks and one
 * XFS_DIR2_LEAF1 block containing the hash table and freespace map.
 */

#include <xfs.h>

static void xfs_dir2_leaf_log_bests(xfs_trans_t *, xfs_dabuf_t *, int, int);
static void xfs_dir2_leaf_log_tail(xfs_trans_t *, xfs_dabuf_t *);

/*
 * 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 */
{
	xfs_dir2_data_off_t	*bestsp;	/* leaf's bestsp entries */
	xfs_dablk_t		blkno;		/* leaf block's bno */
	xfs_dir2_block_t	*block;		/* block structure */
	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 */

	xfs_dir2_trace_args_b("block_to_leaf", args, dbp);
	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;
	block = dbp->data;
	xfs_dir2_data_check(dp, dbp);
	btp = XFS_DIR2_BLOCK_TAIL_P(mp, block);
	blp = XFS_DIR2_BLOCK_LEAF_P(btp);
	/*
	 * Set the counts in the leaf header.
	 */
	INT_COPY(leaf->hdr.count, btp->count, ARCH_CONVERT); /* INT_: type change */
	INT_COPY(leaf->hdr.stale, btp->stale, ARCH_CONVERT); /* INT_: type change */
	/*
	 * Could compact these but I think we always do the conversion
	 * after squeezing out stale entries.
	 */
	memcpy(leaf->ents, blp, INT_GET(btp->count, ARCH_CONVERT) * sizeof(xfs_dir2_leaf_entry_t));
	xfs_dir2_leaf_log_ents(tp, lbp, 0, INT_GET(leaf->hdr.count, ARCH_CONVERT) - 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 *)block),
		(xfs_dir2_data_aoff_t)((char *)block + mp->m_dirblksize -
				       (char *)blp),
		&needlog, &needscan);
	/*
	 * Fix up the block header, make it a data block.
	 */
	INT_SET(block->hdr.magic, ARCH_CONVERT, XFS_DIR2_DATA_MAGIC);
	if (needscan)
		xfs_dir2_data_freescan(mp, (xfs_dir2_data_t *)block, &needlog,
			NULL);
	/*
	 * Set up leaf tail and bests table.
	 */
	ltp = XFS_DIR2_LEAF_TAIL_P(mp, leaf);
	INT_SET(ltp->bestcount, ARCH_CONVERT, 1);
	bestsp = XFS_DIR2_LEAF_BESTS_P(ltp);
	INT_COPY(bestsp[0], block->hdr.bestfree[0].length, ARCH_CONVERT);
	/*
	 * 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;
}

/*
 * Add an entry to a leaf form directory.
 */
int						/* error */
xfs_dir2_leaf_addname(
	xfs_da_args_t		*args)		/* operation arguments */
{
	xfs_dir2_data_off_t	*bestsp;	/* freespace table in leaf */
	int			compact;	/* need to compact leaves */
	xfs_dir2_data_t		*data;		/* data block structure */
	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 */
	xfs_dir2_data_off_t	*tagp;		/* end of data entry */
	xfs_trans_t		*tp;		/* transaction pointer */
	xfs_dir2_db_t		use_block;	/* data block number */

	xfs_dir2_trace_args("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 < INT_GET(leaf->hdr.count, ARCH_CONVERT) && INT_GET(lep->hashval, ARCH_CONVERT) == args->hashval;
	     index++, lep++) {
		if (INT_GET(lep->address, ARCH_CONVERT) == XFS_DIR2_NULL_DATAPTR)
			continue;
		i = XFS_DIR2_DATAPTR_TO_DB(mp, INT_GET(lep->address, ARCH_CONVERT));
		ASSERT(i < INT_GET(ltp->bestcount, ARCH_CONVERT));
		ASSERT(INT_GET(bestsp[i], ARCH_CONVERT) != NULLDATAOFF);
		if (INT_GET(bestsp[i], ARCH_CONVERT) >= 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 < INT_GET(ltp->bestcount, ARCH_CONVERT); i++) {
			/*
			 * Remember a block we see that's missing.
			 */
			if (INT_GET(bestsp[i], ARCH_CONVERT) == NULLDATAOFF && use_block == -1)
				use_block = i;
			else if (INT_GET(bestsp[i], ARCH_CONVERT) >= length) {
				use_block = i;
				break;
			}
		}
	}
	/*
	 * How many bytes do we need in the leaf block?
	 */
	needbytes =
		(leaf->hdr.stale ? 0 : (uint)sizeof(leaf->ents[0])) +
		(use_block != -1 ? 0 : (uint)sizeof(leaf->bests[0]));
	/*
	 * 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 && INT_GET(bestsp[use_block], ARCH_CONVERT) == 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[INT_GET(leaf->hdr.count, ARCH_CONVERT)] < needbytes &&
	    INT_GET(leaf->hdr.stale, ARCH_CONVERT) > 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[INT_GET(leaf->hdr.count, ARCH_CONVERT)] <
		 needbytes) {
		/*
		 * Just checking or no space reservation, give up.
		 */
		if (args->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->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 (INT_GET(leaf->hdr.stale, ARCH_CONVERT)) {
		lfloglow = INT_GET(leaf->hdr.count, ARCH_CONVERT);
		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 >= INT_GET(ltp->bestcount, ARCH_CONVERT)) {
			bestsp--;
			memmove(&bestsp[0], &bestsp[1],
				INT_GET(ltp->bestcount, ARCH_CONVERT) * sizeof(bestsp[0]));
			INT_MOD(ltp->bestcount, ARCH_CONVERT, +1);
			xfs_dir2_leaf_log_tail(tp, lbp);
			xfs_dir2_leaf_log_bests(tp, lbp, 0, INT_GET(ltp->bestcount, ARCH_CONVERT) - 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);
		data = dbp->data;
		INT_COPY(bestsp[use_block], data->hdr.bestfree[0].length, ARCH_CONVERT);
		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;
		}
		data = 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 *)data + INT_GET(data->hdr.bestfree[0].offset, ARCH_CONVERT));
	ASSERT(INT_GET(dup->length, ARCH_CONVERT) >= 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 *)data), length,
		&needlog, &needscan);
	/*
	 * Initialize our new entry (at last).
	 */
	dep = (xfs_dir2_data_entry_t *)dup;
	INT_SET(dep->inumber, ARCH_CONVERT, args->inumber);
	dep->namelen = args->namelen;
	memcpy(dep->name, args->name, dep->namelen);
	tagp = XFS_DIR2_DATA_ENTRY_TAG_P(dep);
	INT_SET(*tagp, ARCH_CONVERT, (xfs_dir2_data_off_t)((char *)dep - (char *)data));
	/*
	 * Need to scan fix up the bestfree table.
	 */
	if (needscan)
		xfs_dir2_data_freescan(mp, data, &needlog, NULL);
	/*
	 * 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 (INT_GET(bestsp[use_block], ARCH_CONVERT) != INT_GET(data->hdr.bestfree[0].length, ARCH_CONVERT)) {
		INT_COPY(bestsp[use_block], data->hdr.bestfree[0].length, ARCH_CONVERT);
		if (!grown)
			xfs_dir2_leaf_log_bests(tp, lbp, use_block, use_block);
	}
	/*
	 * Now we need to make room to insert the leaf entry.
	 * If there are no stale entries, we just insert a hole at index.
	 */
	if (!leaf->hdr.stale) {
		/*
		 * lep is still good as the index leaf entry.
		 */
		if (index < INT_GET(leaf->hdr.count, ARCH_CONVERT))
			memmove(lep + 1, lep,
				(INT_GET(leaf->hdr.count, ARCH_CONVERT) - index) * sizeof(*lep));
		/*
		 * Record low and high logging indices for the leaf.
		 */
		lfloglow = index;
		lfloghigh = INT_GET(leaf->hdr.count, ARCH_CONVERT);
		INT_MOD(leaf->hdr.count, ARCH_CONVERT, +1);
	}
	/*
	 * 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.
	 */
	else {
		/*
		 * If we didn't compact before, we need to find the nearest
		 * stale entries before and after our insertion point.
		 */
		if (compact == 0) {
			/*
			 * Find the first stale entry before the insertion
			 * point, if any.
			 */
			for (lowstale = index - 1;
			     lowstale >= 0 &&
				INT_GET(leaf->ents[lowstale].address, ARCH_CONVERT) !=
				XFS_DIR2_NULL_DATAPTR;
			     lowstale--)
				continue;
			/*
			 * Find the next stale entry at or after the insertion
			 * point, if any.   Stop if we go so far that the
			 * lowstale entry would be better.
			 */
			for (highstale = index;
			     highstale < INT_GET(leaf->hdr.count, ARCH_CONVERT) &&
				INT_GET(leaf->ents[highstale].address, ARCH_CONVERT) !=
				XFS_DIR2_NULL_DATAPTR &&
				(lowstale < 0 ||
				 index - lowstale - 1 >= highstale - index);
			     highstale++)
				continue;
		}
		/*
		 * If the low one is better, use it.
		 */
		if (lowstale >= 0 &&
		    (highstale == INT_GET(leaf->hdr.count, ARCH_CONVERT) ||
		     index - lowstale - 1 < highstale - index)) {
			ASSERT(index - lowstale - 1 >= 0);
			ASSERT(INT_GET(leaf->ents[lowstale].address, ARCH_CONVERT) ==
			       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(*lep));
			lep = &leaf->ents[index - 1];
			lfloglow = MIN(lowstale, lfloglow);
			lfloghigh = MAX(index - 1, lfloghigh);
		}
		/*
		 * The high one is better, so use that one.
		 */
		else {
			ASSERT(highstale - index >= 0);
			ASSERT(INT_GET(leaf->ents[highstale].address, ARCH_CONVERT) ==
			       XFS_DIR2_NULL_DATAPTR);
			/*
			 * Copy entries down to copver 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(*lep));
			lep = &leaf->ents[index];
			lfloglow = MIN(index, lfloglow);
			lfloghigh = MAX(highstale, lfloghigh);
		}
		INT_MOD(leaf->hdr.stale, ARCH_CONVERT, -1);
	}
	/*
	 * Fill in the new leaf entry.
	 */
	INT_SET(lep->hashval, ARCH_CONVERT, args->hashval);
	INT_SET(lep->address, ARCH_CONVERT, XFS_DIR2_DB_OFF_TO_DATAPTR(mp, use_block, INT_GET(*tagp, ARCH_CONVERT)));
	/*
	 * 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.
 */
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(INT_GET(leaf->hdr.info.magic, ARCH_CONVERT) == 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(INT_GET(leaf->hdr.count, ARCH_CONVERT) <= XFS_DIR2_MAX_LEAF_ENTS(mp));
	ltp = XFS_DIR2_LEAF_TAIL_P(mp, leaf);
	/*
	 * Leaves and bests don't overlap.
	 */
	ASSERT((char *)&leaf->ents[INT_GET(leaf->hdr.count, ARCH_CONVERT)] <=
	       (char *)XFS_DIR2_LEAF_BESTS_P(ltp));
	/*
	 * Check hash value order, count stale entries.
	 */
	for (i = stale = 0; i < INT_GET(leaf->hdr.count, ARCH_CONVERT); i++) {
		if (i + 1 < INT_GET(leaf->hdr.count, ARCH_CONVERT))
			ASSERT(INT_GET(leaf->ents[i].hashval, ARCH_CONVERT) <=
			       INT_GET(leaf->ents[i + 1].hashval, ARCH_CONVERT));
		if (INT_GET(leaf->ents[i].address, ARCH_CONVERT) == XFS_DIR2_NULL_DATAPTR)
			stale++;
	}
	ASSERT(INT_GET(leaf->hdr.stale, ARCH_CONVERT) == 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 < INT_GET(leaf->hdr.count, ARCH_CONVERT); from++) {
		if (INT_GET(leaf->ents[from].address, ARCH_CONVERT) == 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(INT_GET(leaf->hdr.stale, ARCH_CONVERT) == from - to);
	INT_MOD(leaf->hdr.count, ARCH_CONVERT, -(INT_GET(leaf->hdr.stale, ARCH_CONVERT)));
	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(INT_GET(leaf->hdr.stale, ARCH_CONVERT) > 1);
	index = *indexp;
	/*
	 * Find the first stale entry before our index, if any.
	 */
	for (lowstale = index - 1;
	     lowstale >= 0 &&
		INT_GET(leaf->ents[lowstale].address, ARCH_CONVERT) != XFS_DIR2_NULL_DATAPTR;
	     lowstale--)
		continue;
	/*
	 * Find the first stale entry at or after our index, if any.
	 * Stop if the answer would be worse than lowstale.
	 */
	for (highstale = index;
	     highstale < INT_GET(leaf->hdr.count, ARCH_CONVERT) &&
		INT_GET(leaf->ents[highstale].address, ARCH_CONVERT) != XFS_DIR2_NULL_DATAPTR &&
		(lowstale < 0 || index - lowstale > highstale - index);
	     highstale++)
		continue;
	/*
	 * Pick the better of lowstale and highstale.
	 */
	if (lowstale >= 0 &&
	    (highstale == INT_GET(leaf->hdr.count, ARCH_CONVERT) ||
	     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 < INT_GET(leaf->hdr.count, ARCH_CONVERT); from++) {
		/*
		 * Notice the new value of index.
		 */
		if (index == from)
			newindex = to;
		if (from != keepstale &&
		    INT_GET(leaf->ents[from].address, ARCH_CONVERT) == 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.
	 */
	INT_MOD(leaf->hdr.count, ARCH_CONVERT, -(from - to));
	INT_SET(leaf->hdr.stale, ARCH_CONVERT, 1);
	/*
	 * Remember the low/high stale value only in the "right"
	 * direction.
	 */
	if (lowstale >= newindex)
		lowstale = -1;
	else
		highstale = INT_GET(leaf->hdr.count, ARCH_CONVERT);
	*highlogp = INT_GET(leaf->hdr.count, ARCH_CONVERT) - 1;
	*lowstalep = lowstale;
	*highstalep = highstale;
}

/*
 * 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.
	 */
	INT_SET(leaf->hdr.info.magic, ARCH_CONVERT, 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.
 */
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 */
{
	xfs_dir2_data_off_t	*firstb;	/* pointer to first entry */
	xfs_dir2_data_off_t	*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(INT_GET(leaf->hdr.info.magic, ARCH_CONVERT) == 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(INT_GET(leaf->hdr.info.magic, ARCH_CONVERT) == XFS_DIR2_LEAF1_MAGIC ||
	       INT_GET(leaf->hdr.info.magic, ARCH_CONVERT) == 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(INT_GET(leaf->hdr.info.magic, ARCH_CONVERT) == XFS_DIR2_LEAF1_MAGIC ||
	       INT_GET(leaf->hdr.info.magic, ARCH_CONVERT) == 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(INT_GET(leaf->hdr.info.magic, ARCH_CONVERT) == 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 */

	xfs_dir2_trace_args("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, INT_GET(lep->address, ARCH_CONVERT)));
	/*
	 * Return the found inode number.
	 */
	args->inumber = INT_GET(dep->inumber, ARCH_CONVERT);
	xfs_da_brelse(tp, dbp);
	xfs_da_brelse(tp, lbp);
	return XFS_ERROR(EEXIST);
}

/*
 * 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;		/* current data block number */
	xfs_dabuf_t		*dbp;		/* 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 */

	dp = args->dp;
	tp = args->trans;
	mp = dp->i_mount;
	/*
	 * Read the leaf block into the buffer.
	 */
	if ((error =
	    xfs_da_read_buf(tp, dp, mp->m_dirleafblk, -1, &lbp,
		    XFS_DATA_FORK))) {
		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], dbp = NULL, curdb = -1;
	     index < INT_GET(leaf->hdr.count, ARCH_CONVERT) && INT_GET(lep->hashval, ARCH_CONVERT) == args->hashval;
	     lep++, index++) {
		/*
		 * Skip over stale leaf entries.
		 */
		if (INT_GET(lep->address, ARCH_CONVERT) == XFS_DIR2_NULL_DATAPTR)
			continue;
		/*
		 * Get the new data block number.
		 */
		newdb = XFS_DIR2_DATAPTR_TO_DB(mp, INT_GET(lep->address, ARCH_CONVERT));
		/*
		 * 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);
			if ((error =
			    xfs_da_read_buf(tp, dp,
				    XFS_DIR2_DB_TO_DA(mp, newdb), -1, &dbp,
				    XFS_DATA_FORK))) {
				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, INT_GET(lep->address, ARCH_CONVERT)));
		/*
		 * If it matches then return it.
		 */
		if (dep->namelen == args->namelen &&
		    dep->name[0] == args->name[0] &&
		    memcmp(dep->name, args->name, args->namelen) == 0) {
			*dbpp = dbp;
			*indexp = index;
			return 0;
		}
	}
	/*
	 * No match found, return ENOENT.
	 */
	ASSERT(args->oknoent);
	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 */
{
	xfs_dir2_data_off_t	*bestsp;	/* leaf block best freespace */
	xfs_dir2_data_t		*data;		/* data block structure */
	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 */

	xfs_dir2_trace_args("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;
	data = 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, INT_GET(lep->address, ARCH_CONVERT));
	dep = (xfs_dir2_data_entry_t *)
	      ((char *)data + XFS_DIR2_DATAPTR_TO_OFF(mp, INT_GET(lep->address, ARCH_CONVERT)));
	needscan = needlog = 0;
	oldbest = INT_GET(data->hdr.bestfree[0].length, ARCH_CONVERT);
	ltp = XFS_DIR2_LEAF_TAIL_P(mp, leaf);
	bestsp = XFS_DIR2_LEAF_BESTS_P(ltp);
	ASSERT(INT_GET(bestsp[db], ARCH_CONVERT) == oldbest);
	/*
	 * Mark the former data entry unused.
	 */
	xfs_dir2_data_make_free(tp, dbp,
		(xfs_dir2_data_aoff_t)((char *)dep - (char *)data),
		XFS_DIR2_DATA_ENTSIZE(dep->namelen), &needlog, &needscan);
	/*
	 * We just mark the leaf entry stale by putting a null in it.
	 */
	INT_MOD(leaf->hdr.stale, ARCH_CONVERT, +1);
	xfs_dir2_leaf_log_header(tp, lbp);
	INT_SET(lep->address, ARCH_CONVERT, 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, data, &needlog, NULL);
	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 (INT_GET(data->hdr.bestfree[0].length, ARCH_CONVERT) != oldbest) {
		INT_COPY(bestsp[db], data->hdr.bestfree[0].length, ARCH_CONVERT);
		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 (INT_GET(data->hdr.bestfree[0].length, ARCH_CONVERT) ==
	    mp->m_dirblksize - (uint)sizeof(data->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 == INT_GET(ltp->bestcount, ARCH_CONVERT) - 1) {
			/*
			 * Look for the last active entry (i).
			 */
			for (i = db - 1; i > 0; i--) {
				if (INT_GET(bestsp[i], ARCH_CONVERT) != NULLDATAOFF)
					break;
			}
			/*
			 * Copy the table down so inactive entries at the
			 * end are removed.
			 */
			memmove(&bestsp[db - i], bestsp,
				(INT_GET(ltp->bestcount, ARCH_CONVERT) - (db - i)) * sizeof(*bestsp));
			INT_MOD(ltp->bestcount, ARCH_CONVERT, -(db - i));
			xfs_dir2_leaf_log_tail(tp, lbp);
			xfs_dir2_leaf_log_bests(tp, lbp, 0, INT_GET(ltp->bestcount, ARCH_CONVERT) - 1);
		} else
			INT_SET(bestsp[db], ARCH_CONVERT, 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 */

	xfs_dir2_trace_args("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, INT_GET(lep->address, ARCH_CONVERT)));
	ASSERT(args->inumber != INT_GET(dep->inumber, ARCH_CONVERT));
	/*
	 * Put the new inode number in, log it.
	 */
	INT_SET(dep->inumber, ARCH_CONVERT, 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 = INT_GET(leaf->hdr.count, ARCH_CONVERT) - 1,
		hashwant = args->hashval;
	     low <= high; ) {
		mid = (low + high) >> 1;
		if ((hash = INT_GET(lep[mid].hashval, ARCH_CONVERT)) == 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 && INT_GET(lep[mid - 1].hashval, ARCH_CONVERT) == 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 */
{
	xfs_dir2_data_off_t	*bestsp;	/* leaf bests table */
#ifdef DEBUG
	xfs_dir2_data_t		*data;		/* data block structure */
#endif
	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;
	}
#ifdef DEBUG
	data = dbp->data;
	ASSERT(INT_GET(data->hdr.magic, ARCH_CONVERT) == XFS_DIR2_DATA_MAGIC);
#endif
	/* this seems to be an error
	 * data is only valid if DEBUG is defined?
	 * RMC 09/08/1999
	 */

	leaf = lbp->data;
	ltp = XFS_DIR2_LEAF_TAIL_P(mp, leaf);
	ASSERT(INT_GET(data->hdr.bestfree[0].length, ARCH_CONVERT) ==
	       mp->m_dirblksize - (uint)sizeof(data->hdr));
	ASSERT(db == INT_GET(ltp->bestcount, ARCH_CONVERT) - 1);
	/*
	 * 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);
	INT_MOD(ltp->bestcount, ARCH_CONVERT, -1);
	memmove(&bestsp[1], &bestsp[0], INT_GET(ltp->bestcount, ARCH_CONVERT) * sizeof(*bestsp));
	xfs_dir2_leaf_log_tail(tp, lbp);
	xfs_dir2_leaf_log_bests(tp, lbp, 0, INT_GET(ltp->bestcount, ARCH_CONVERT) - 1);
	return 0;
}

/*
 * 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;
	xfs_dir2_trace_args("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(INT_GET(leaf->hdr.info.magic, ARCH_CONVERT) == 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(INT_GET(free->hdr.magic, ARCH_CONVERT) == 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 ((uint)sizeof(leaf->hdr) +
	    (INT_GET(leaf->hdr.count, ARCH_CONVERT) - INT_GET(leaf->hdr.stale, ARCH_CONVERT)) * (uint)sizeof(leaf->ents[0]) +
	    INT_GET(free->hdr.nvalid, ARCH_CONVERT) * (uint)sizeof(leaf->bests[0]) +
	    (uint)sizeof(leaf->tail) >
	    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 (INT_GET(leaf->hdr.stale, ARCH_CONVERT))
		xfs_dir2_leaf_compact(args, lbp);
	else
		xfs_dir2_leaf_log_header(tp, lbp);
	INT_SET(leaf->hdr.info.magic, ARCH_CONVERT, XFS_DIR2_LEAF1_MAGIC);
	/*
	 * Set up the leaf tail from the freespace block.
	 */
	ltp = XFS_DIR2_LEAF_TAIL_P(mp, leaf);
	INT_COPY(ltp->bestcount, free->hdr.nvalid, ARCH_CONVERT);
	/*
	 * Set up the leaf bests table.
	 */
	memcpy(XFS_DIR2_LEAF_BESTS_P(ltp), free->bests,
		INT_GET(ltp->bestcount, ARCH_CONVERT) * sizeof(leaf->bests[0]));
	xfs_dir2_leaf_log_bests(tp, lbp, 0, INT_GET(ltp->bestcount, ARCH_CONVERT) - 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;
}