xfs_dir2_node.c

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/*
 * Copyright (c) 2000-2005 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_log.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"

/*
 * Function declarations.
 */
static int xfs_dir2_leafn_add(struct xfs_buf *bp, xfs_da_args_t *args,
                  int index);
#ifdef DEBUG
static void xfs_dir2_leafn_check(struct xfs_inode *dp, struct xfs_buf *bp);
#else
#define xfs_dir2_leafn_check(dp, bp)
#endif
static void xfs_dir2_leafn_moveents(xfs_da_args_t *args, struct xfs_buf *bp_s,
                    int start_s, struct xfs_buf *bp_d,
                    int start_d, int count);
static void xfs_dir2_leafn_rebalance(xfs_da_state_t *state,
                     xfs_da_state_blk_t *blk1,
                     xfs_da_state_blk_t *blk2);
static int xfs_dir2_leafn_remove(xfs_da_args_t *args, struct xfs_buf *bp,
                 int index, xfs_da_state_blk_t *dblk,
                 int *rval);
static int xfs_dir2_node_addname_int(xfs_da_args_t *args,
                     xfs_da_state_blk_t *fblk);

/*
 * Log entries from a freespace block.
 */
STATIC void
xfs_dir2_free_log_bests(
    struct xfs_trans    *tp,
    struct xfs_buf      *bp,
    int         first,      /* first entry to log */
    int         last)       /* last entry to log */
{
    xfs_dir2_free_t     *free;      /* freespace structure */

    free = bp->b_addr;
    ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC));
    xfs_trans_log_buf(tp, bp,
        (uint)((char *)&free->bests[first] - (char *)free),
        (uint)((char *)&free->bests[last] - (char *)free +
               sizeof(free->bests[0]) - 1));
}

/*
 * Log header from a freespace block.
 */
static void
xfs_dir2_free_log_header(
    struct xfs_trans    *tp,
    struct xfs_buf      *bp)
{
    xfs_dir2_free_t     *free;      /* freespace structure */

    free = bp->b_addr;
    ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC));
    xfs_trans_log_buf(tp, bp, (uint)((char *)&free->hdr - (char *)free),
        (uint)(sizeof(xfs_dir2_free_hdr_t) - 1));
}

/*
 * Convert a leaf-format directory to a node-format directory.
 * We need to change the magic number of the leaf block, and copy
 * the freespace table out of the leaf block into its own block.
 */
int                     /* error */
xfs_dir2_leaf_to_node(
    xfs_da_args_t       *args,      /* operation arguments */
    struct xfs_buf      *lbp)       /* leaf buffer */
{
    xfs_inode_t     *dp;        /* incore directory inode */
    int         error;      /* error return value */
    struct xfs_buf      *fbp;       /* freespace buffer */
    xfs_dir2_db_t       fdb;        /* freespace block number */
    xfs_dir2_free_t     *free;      /* freespace structure */
    __be16          *from;      /* pointer to freespace entry */
    int         i;      /* leaf freespace index */
    xfs_dir2_leaf_t     *leaf;      /* leaf structure */
    xfs_dir2_leaf_tail_t    *ltp;       /* leaf tail structure */
    xfs_mount_t     *mp;        /* filesystem mount point */
    int         n;      /* count of live freespc ents */
    xfs_dir2_data_off_t off;        /* freespace entry value */
    __be16          *to;        /* pointer to freespace entry */
    xfs_trans_t     *tp;        /* transaction pointer */

    trace_xfs_dir2_leaf_to_node(args);

    dp = args->dp;
    mp = dp->i_mount;
    tp = args->trans;
    /*
     * Add a freespace block to the directory.
     */
    if ((error = xfs_dir2_grow_inode(args, XFS_DIR2_FREE_SPACE, &fdb))) {
        return error;
    }
    ASSERT(fdb == XFS_DIR2_FREE_FIRSTDB(mp));
    /*
     * Get the buffer for the new freespace block.
     */
    if ((error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(mp, fdb), -1, &fbp,
            XFS_DATA_FORK))) {
        return error;
    }
    ASSERT(fbp != NULL);
    free = fbp->b_addr;
    leaf = lbp->b_addr;
    ltp = xfs_dir2_leaf_tail_p(mp, leaf);
    /*
     * Initialize the freespace block header.
     */
    free->hdr.magic = cpu_to_be32(XFS_DIR2_FREE_MAGIC);
    free->hdr.firstdb = 0;
    ASSERT(be32_to_cpu(ltp->bestcount) <= (uint)dp->i_d.di_size / mp->m_dirblksize);
    free->hdr.nvalid = ltp->bestcount;
    /*
     * Copy freespace entries from the leaf block to the new block.
     * Count active entries.
     */
    for (i = n = 0, from = xfs_dir2_leaf_bests_p(ltp), to = free->bests;
         i < be32_to_cpu(ltp->bestcount); i++, from++, to++) {
        if ((off = be16_to_cpu(*from)) != NULLDATAOFF)
            n++;
        *to = cpu_to_be16(off);
    }
    free->hdr.nused = cpu_to_be32(n);
    leaf->hdr.info.magic = cpu_to_be16(XFS_DIR2_LEAFN_MAGIC);
    /*
     * Log everything.
     */
    xfs_dir2_leaf_log_header(tp, lbp);
    xfs_dir2_free_log_header(tp, fbp);
    xfs_dir2_free_log_bests(tp, fbp, 0, be32_to_cpu(free->hdr.nvalid) - 1);
    xfs_dir2_leafn_check(dp, lbp);
    return 0;
}

/*
 * Add a leaf entry to a leaf block in a node-form directory.
 * The other work necessary is done from the caller.
 */
static int                  /* error */
xfs_dir2_leafn_add(
    struct xfs_buf      *bp,        /* leaf buffer */
    xfs_da_args_t       *args,      /* operation arguments */
    int         index)      /* insertion pt for new entry */
{
    int         compact;    /* compacting stale leaves */
    xfs_inode_t     *dp;        /* incore directory inode */
    int         highstale;  /* next stale entry */
    xfs_dir2_leaf_t     *leaf;      /* leaf structure */
    xfs_dir2_leaf_entry_t   *lep;       /* leaf entry */
    int         lfloghigh;  /* high leaf entry logging */
    int         lfloglow;   /* low leaf entry logging */
    int         lowstale;   /* previous stale entry */
    xfs_mount_t     *mp;        /* filesystem mount point */
    xfs_trans_t     *tp;        /* transaction pointer */

    trace_xfs_dir2_leafn_add(args, index);

    dp = args->dp;
    mp = dp->i_mount;
    tp = args->trans;
    leaf = bp->b_addr;

    /*
     * Quick check just to make sure we are not going to index
     * into other peoples memory
     */
    if (index < 0)
        return XFS_ERROR(EFSCORRUPTED);

    /*
     * If there are already the maximum number of leaf entries in
     * the block, if there are no stale entries it won't fit.
     * Caller will do a split.  If there are stale entries we'll do
     * a compact.
     */

    if (be16_to_cpu(leaf->hdr.count) == xfs_dir2_max_leaf_ents(mp)) {
        if (!leaf->hdr.stale)
            return XFS_ERROR(ENOSPC);
        compact = be16_to_cpu(leaf->hdr.stale) > 1;
    } else
        compact = 0;
    ASSERT(index == 0 || be32_to_cpu(leaf->ents[index - 1].hashval) <= args->hashval);
    ASSERT(index == be16_to_cpu(leaf->hdr.count) ||
           be32_to_cpu(leaf->ents[index].hashval) >= args->hashval);

    if (args->op_flags & XFS_DA_OP_JUSTCHECK)
        return 0;

    /*
     * Compact out all but one stale leaf entry.  Leaves behind
     * the entry closest to index.
     */
    if (compact) {
        xfs_dir2_leaf_compact_x1(bp, &index, &lowstale, &highstale,
            &lfloglow, &lfloghigh);
    }
    /*
     * Set impossible logging indices for this case.
     */
    else if (leaf->hdr.stale) {
        lfloglow = be16_to_cpu(leaf->hdr.count);
        lfloghigh = -1;
    }

    /*
     * Insert the new entry, log everything.
     */
    lep = xfs_dir2_leaf_find_entry(leaf, index, compact, lowstale,
                       highstale, &lfloglow, &lfloghigh);

    lep->hashval = cpu_to_be32(args->hashval);
    lep->address = cpu_to_be32(xfs_dir2_db_off_to_dataptr(mp,
                args->blkno, args->index));
    xfs_dir2_leaf_log_header(tp, bp);
    xfs_dir2_leaf_log_ents(tp, bp, lfloglow, lfloghigh);
    xfs_dir2_leafn_check(dp, bp);
    return 0;
}

#ifdef DEBUG
/*
 * Check internal consistency of a leafn block.
 */
void
xfs_dir2_leafn_check(
    struct xfs_inode *dp,
    struct xfs_buf  *bp)
{
    int     i;          /* leaf index */
    xfs_dir2_leaf_t *leaf;          /* leaf structure */
    xfs_mount_t *mp;            /* filesystem mount point */
    int     stale;          /* count of stale leaves */

    leaf = bp->b_addr;
    mp = dp->i_mount;
    ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
    ASSERT(be16_to_cpu(leaf->hdr.count) <= xfs_dir2_max_leaf_ents(mp));
    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 */

/*
 * Return the last hash value in the leaf.
 * Stale entries are ok.
 */
xfs_dahash_t                    /* hash value */
xfs_dir2_leafn_lasthash(
    struct xfs_buf  *bp,            /* leaf buffer */
    int     *count)         /* count of entries in leaf */
{
    xfs_dir2_leaf_t *leaf;          /* leaf structure */

    leaf = bp->b_addr;
    ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
    if (count)
        *count = be16_to_cpu(leaf->hdr.count);
    if (!leaf->hdr.count)
        return 0;
    return be32_to_cpu(leaf->ents[be16_to_cpu(leaf->hdr.count) - 1].hashval);
}

/*
 * Look up a leaf entry for space to add a name in a node-format leaf block.
 * The extrablk in state is a freespace block.
 */
STATIC int
xfs_dir2_leafn_lookup_for_addname(
    struct xfs_buf      *bp,        /* leaf buffer */
    xfs_da_args_t       *args,      /* operation arguments */
    int         *indexp,    /* out: leaf entry index */
    xfs_da_state_t      *state)     /* state to fill in */
{
    struct xfs_buf      *curbp = NULL;  /* current data/free buffer */
    xfs_dir2_db_t       curdb = -1; /* current data block number */
    xfs_dir2_db_t       curfdb = -1;    /* current free block number */
    xfs_inode_t     *dp;        /* incore directory inode */
    int         error;      /* error return value */
    int         fi;     /* free entry index */
    xfs_dir2_free_t     *free = NULL;   /* free block structure */
    int         index;      /* leaf entry index */
    xfs_dir2_leaf_t     *leaf;      /* leaf structure */
    int         length;     /* length of new data entry */
    xfs_dir2_leaf_entry_t   *lep;       /* leaf entry */
    xfs_mount_t     *mp;        /* filesystem mount point */
    xfs_dir2_db_t       newdb;      /* new data block number */
    xfs_dir2_db_t       newfdb;     /* new free block number */
    xfs_trans_t     *tp;        /* transaction pointer */

    dp = args->dp;
    tp = args->trans;
    mp = dp->i_mount;
    leaf = bp->b_addr;
    ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
#ifdef __KERNEL__
    ASSERT(be16_to_cpu(leaf->hdr.count) > 0);
#endif
    xfs_dir2_leafn_check(dp, bp);
    /*
     * Look up the hash value in the leaf entries.
     */
    index = xfs_dir2_leaf_search_hash(args, bp);
    /*
     * Do we have a buffer coming in?
     */
    if (state->extravalid) {
        /* If so, it's a free block buffer, get the block number. */
        curbp = state->extrablk.bp;
        curfdb = state->extrablk.blkno;
        free = curbp->b_addr;
        ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC));
    }
    length = xfs_dir2_data_entsize(args->namelen);
    /*
     * Loop over leaf entries with the right hash value.
     */
    for (lep = &leaf->ents[index]; index < be16_to_cpu(leaf->hdr.count) &&
                be32_to_cpu(lep->hashval) == args->hashval;
                lep++, index++) {
        /*
         * Skip stale leaf entries.
         */
        if (be32_to_cpu(lep->address) == XFS_DIR2_NULL_DATAPTR)
            continue;
        /*
         * Pull the data block number from the entry.
         */
        newdb = xfs_dir2_dataptr_to_db(mp, be32_to_cpu(lep->address));
        /*
         * For addname, we're looking for a place to put the new entry.
         * We want to use a data block with an entry of equal
         * hash value to ours if there is one with room.
         *
         * If this block isn't the data block we already have
         * in hand, take a look at it.
         */
        if (newdb != curdb) {
            curdb = newdb;
            /*
             * Convert the data block to the free block
             * holding its freespace information.
             */
            newfdb = xfs_dir2_db_to_fdb(mp, newdb);
            /*
             * If it's not the one we have in hand, read it in.
             */
            if (newfdb != curfdb) {
                /*
                 * If we had one before, drop it.
                 */
                if (curbp)
                    xfs_trans_brelse(tp, curbp);
                /*
                 * Read the free block.
                 */
                error = xfs_da_read_buf(tp, dp,
                        xfs_dir2_db_to_da(mp, newfdb),
                        -1, &curbp, XFS_DATA_FORK);
                if (error)
                    return error;
                free = curbp->b_addr;
                ASSERT(be32_to_cpu(free->hdr.magic) ==
                    XFS_DIR2_FREE_MAGIC);
                ASSERT((be32_to_cpu(free->hdr.firstdb) %
                    xfs_dir2_free_max_bests(mp)) == 0);
                ASSERT(be32_to_cpu(free->hdr.firstdb) <= curdb);
                ASSERT(curdb < be32_to_cpu(free->hdr.firstdb) +
                    be32_to_cpu(free->hdr.nvalid));
            }
            /*
             * Get the index for our entry.
             */
            fi = xfs_dir2_db_to_fdindex(mp, curdb);
            /*
             * If it has room, return it.
             */
            if (unlikely(free->bests[fi] ==
                cpu_to_be16(NULLDATAOFF))) {
                XFS_ERROR_REPORT("xfs_dir2_leafn_lookup_int",
                            XFS_ERRLEVEL_LOW, mp);
                if (curfdb != newfdb)
                    xfs_trans_brelse(tp, curbp);
                return XFS_ERROR(EFSCORRUPTED);
            }
            curfdb = newfdb;
            if (be16_to_cpu(free->bests[fi]) >= length)
                goto out;
        }
    }
    /* Didn't find any space */
    fi = -1;
out:
    ASSERT(args->op_flags & XFS_DA_OP_OKNOENT);
    if (curbp) {
        /* Giving back a free block. */
        state->extravalid = 1;
        state->extrablk.bp = curbp;
        state->extrablk.index = fi;
        state->extrablk.blkno = curfdb;
        state->extrablk.magic = XFS_DIR2_FREE_MAGIC;
    } else {
        state->extravalid = 0;
    }
    /*
     * Return the index, that will be the insertion point.
     */
    *indexp = index;
    return XFS_ERROR(ENOENT);
}

/*
 * Look up a leaf entry in a node-format leaf block.
 * The extrablk in state a data block.
 */
STATIC int
xfs_dir2_leafn_lookup_for_entry(
    struct xfs_buf      *bp,        /* leaf buffer */
    xfs_da_args_t       *args,      /* operation arguments */
    int         *indexp,    /* out: leaf entry index */
    xfs_da_state_t      *state)     /* state to fill in */
{
    struct xfs_buf      *curbp = NULL;  /* current data/free buffer */
    xfs_dir2_db_t       curdb = -1; /* current data block number */
    xfs_dir2_data_entry_t   *dep;       /* data block entry */
    xfs_inode_t     *dp;        /* incore directory inode */
    int         error;      /* error return value */
    int         index;      /* leaf entry index */
    xfs_dir2_leaf_t     *leaf;      /* leaf structure */
    xfs_dir2_leaf_entry_t   *lep;       /* leaf entry */
    xfs_mount_t     *mp;        /* filesystem mount point */
    xfs_dir2_db_t       newdb;      /* new data block number */
    xfs_trans_t     *tp;        /* transaction pointer */
    enum xfs_dacmp      cmp;        /* comparison result */

    dp = args->dp;
    tp = args->trans;
    mp = dp->i_mount;
    leaf = bp->b_addr;
    ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
#ifdef __KERNEL__
    ASSERT(be16_to_cpu(leaf->hdr.count) > 0);
#endif
    xfs_dir2_leafn_check(dp, bp);
    /*
     * Look up the hash value in the leaf entries.
     */
    index = xfs_dir2_leaf_search_hash(args, bp);
    /*
     * Do we have a buffer coming in?
     */
    if (state->extravalid) {
        curbp = state->extrablk.bp;
        curdb = state->extrablk.blkno;
    }
    /*
     * Loop over leaf entries with the right hash value.
     */
    for (lep = &leaf->ents[index]; index < be16_to_cpu(leaf->hdr.count) &&
                be32_to_cpu(lep->hashval) == args->hashval;
                lep++, index++) {
        /*
         * Skip stale leaf entries.
         */
        if (be32_to_cpu(lep->address) == XFS_DIR2_NULL_DATAPTR)
            continue;
        /*
         * Pull the data block number from the entry.
         */
        newdb = xfs_dir2_dataptr_to_db(mp, be32_to_cpu(lep->address));
        /*
         * Not adding a new entry, so we really want to find
         * the name given to us.
         *
         * If it's a different data block, go get it.
         */
        if (newdb != curdb) {
            /*
             * If we had a block before that we aren't saving
             * for a CI name, drop it
             */
            if (curbp && (args->cmpresult == XFS_CMP_DIFFERENT ||
                        curdb != state->extrablk.blkno))
                xfs_trans_brelse(tp, curbp);
            /*
             * If needing the block that is saved with a CI match,
             * use it otherwise read in the new data block.
             */
            if (args->cmpresult != XFS_CMP_DIFFERENT &&
                    newdb == state->extrablk.blkno) {
                ASSERT(state->extravalid);
                curbp = state->extrablk.bp;
            } else {
                error = xfs_da_read_buf(tp, dp,
                        xfs_dir2_db_to_da(mp, newdb),
                        -1, &curbp, XFS_DATA_FORK);
                if (error)
                    return error;
            }
            xfs_dir2_data_check(dp, curbp);
            curdb = newdb;
        }
        /*
         * Point to the data entry.
         */
        dep = (xfs_dir2_data_entry_t *)((char *)curbp->b_addr +
            xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address)));
        /*
         * Compare the entry and if it's an exact match, return
         * EEXIST immediately. If it's the first case-insensitive
         * match, store the block & inode number and continue looking.
         */
        cmp = mp->m_dirnameops->compname(args, dep->name, dep->namelen);
        if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) {
            /* If there is a CI match block, drop it */
            if (args->cmpresult != XFS_CMP_DIFFERENT &&
                        curdb != state->extrablk.blkno)
                xfs_trans_brelse(tp, state->extrablk.bp);
            args->cmpresult = cmp;
            args->inumber = be64_to_cpu(dep->inumber);
            *indexp = index;
            state->extravalid = 1;
            state->extrablk.bp = curbp;
            state->extrablk.blkno = curdb;
            state->extrablk.index = (int)((char *)dep -
                            (char *)curbp->b_addr);
            state->extrablk.magic = XFS_DIR2_DATA_MAGIC;
            if (cmp == XFS_CMP_EXACT)
                return XFS_ERROR(EEXIST);
        }
    }
    ASSERT(index == be16_to_cpu(leaf->hdr.count) ||
                    (args->op_flags & XFS_DA_OP_OKNOENT));
    if (curbp) {
        if (args->cmpresult == XFS_CMP_DIFFERENT) {
            /* Giving back last used data block. */
            state->extravalid = 1;
            state->extrablk.bp = curbp;
            state->extrablk.index = -1;
            state->extrablk.blkno = curdb;
            state->extrablk.magic = XFS_DIR2_DATA_MAGIC;
        } else {
            /* If the curbp is not the CI match block, drop it */
            if (state->extrablk.bp != curbp)
                xfs_trans_brelse(tp, curbp);
        }
    } else {
        state->extravalid = 0;
    }
    *indexp = index;
    return XFS_ERROR(ENOENT);
}

/*
 * Look up a leaf entry in a node-format leaf block.
 * If this is an addname then the extrablk in state is a freespace block,
 * otherwise it's a data block.
 */
int
xfs_dir2_leafn_lookup_int(
    struct xfs_buf      *bp,        /* leaf buffer */
    xfs_da_args_t       *args,      /* operation arguments */
    int         *indexp,    /* out: leaf entry index */
    xfs_da_state_t      *state)     /* state to fill in */
{
    if (args->op_flags & XFS_DA_OP_ADDNAME)
        return xfs_dir2_leafn_lookup_for_addname(bp, args, indexp,
                            state);
    return xfs_dir2_leafn_lookup_for_entry(bp, args, indexp, state);
}

/*
 * Move count leaf entries from source to destination leaf.
 * Log entries and headers.  Stale entries are preserved.
 */
static void
xfs_dir2_leafn_moveents(
    xfs_da_args_t   *args,          /* operation arguments */
    struct xfs_buf  *bp_s,          /* source leaf buffer */
    int     start_s,        /* source leaf index */
    struct xfs_buf  *bp_d,          /* destination leaf buffer */
    int     start_d,        /* destination leaf index */
    int     count)          /* count of leaves to copy */
{
    xfs_dir2_leaf_t *leaf_d;        /* destination leaf structure */
    xfs_dir2_leaf_t *leaf_s;        /* source leaf structure */
    int     stale;          /* count stale leaves copied */
    xfs_trans_t *tp;            /* transaction pointer */

    trace_xfs_dir2_leafn_moveents(args, start_s, start_d, count);

    /*
     * Silently return if nothing to do.
     */
    if (count == 0) {
        return;
    }
    tp = args->trans;
    leaf_s = bp_s->b_addr;
    leaf_d = bp_d->b_addr;
    /*
     * If the destination index is not the end of the current
     * destination leaf entries, open up a hole in the destination
     * to hold the new entries.
     */
    if (start_d < be16_to_cpu(leaf_d->hdr.count)) {
        memmove(&leaf_d->ents[start_d + count], &leaf_d->ents[start_d],
            (be16_to_cpu(leaf_d->hdr.count) - start_d) *
            sizeof(xfs_dir2_leaf_entry_t));
        xfs_dir2_leaf_log_ents(tp, bp_d, start_d + count,
            count + be16_to_cpu(leaf_d->hdr.count) - 1);
    }
    /*
     * If the source has stale leaves, count the ones in the copy range
     * so we can update the header correctly.
     */
    if (leaf_s->hdr.stale) {
        int i;          /* temp leaf index */

        for (i = start_s, stale = 0; i < start_s + count; i++) {
            if (leaf_s->ents[i].address ==
                cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
                stale++;
        }
    } else
        stale = 0;
    /*
     * Copy the leaf entries from source to destination.
     */
    memcpy(&leaf_d->ents[start_d], &leaf_s->ents[start_s],
        count * sizeof(xfs_dir2_leaf_entry_t));
    xfs_dir2_leaf_log_ents(tp, bp_d, start_d, start_d + count - 1);
    /*
     * If there are source entries after the ones we copied,
     * delete the ones we copied by sliding the next ones down.
     */
    if (start_s + count < be16_to_cpu(leaf_s->hdr.count)) {
        memmove(&leaf_s->ents[start_s], &leaf_s->ents[start_s + count],
            count * sizeof(xfs_dir2_leaf_entry_t));
        xfs_dir2_leaf_log_ents(tp, bp_s, start_s, start_s + count - 1);
    }
    /*
     * Update the headers and log them.
     */
    be16_add_cpu(&leaf_s->hdr.count, -(count));
    be16_add_cpu(&leaf_s->hdr.stale, -(stale));
    be16_add_cpu(&leaf_d->hdr.count, count);
    be16_add_cpu(&leaf_d->hdr.stale, stale);
    xfs_dir2_leaf_log_header(tp, bp_s);
    xfs_dir2_leaf_log_header(tp, bp_d);
    xfs_dir2_leafn_check(args->dp, bp_s);
    xfs_dir2_leafn_check(args->dp, bp_d);
}

/*
 * Determine the sort order of two leaf blocks.
 * Returns 1 if both are valid and leaf2 should be before leaf1, else 0.
 */
int                     /* sort order */
xfs_dir2_leafn_order(
    struct xfs_buf  *leaf1_bp,      /* leaf1 buffer */
    struct xfs_buf  *leaf2_bp)      /* leaf2 buffer */
{
    xfs_dir2_leaf_t *leaf1;         /* leaf1 structure */
    xfs_dir2_leaf_t *leaf2;         /* leaf2 structure */

    leaf1 = leaf1_bp->b_addr;
    leaf2 = leaf2_bp->b_addr;
    ASSERT(leaf1->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
    ASSERT(leaf2->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
    if (be16_to_cpu(leaf1->hdr.count) > 0 &&
        be16_to_cpu(leaf2->hdr.count) > 0 &&
        (be32_to_cpu(leaf2->ents[0].hashval) < be32_to_cpu(leaf1->ents[0].hashval) ||
         be32_to_cpu(leaf2->ents[be16_to_cpu(leaf2->hdr.count) - 1].hashval) <
         be32_to_cpu(leaf1->ents[be16_to_cpu(leaf1->hdr.count) - 1].hashval)))
        return 1;
    return 0;
}

/*
 * Rebalance leaf entries between two leaf blocks.
 * This is actually only called when the second block is new,
 * though the code deals with the general case.
 * A new entry will be inserted in one of the blocks, and that
 * entry is taken into account when balancing.
 */
static void
xfs_dir2_leafn_rebalance(
    xfs_da_state_t      *state,     /* btree cursor */
    xfs_da_state_blk_t  *blk1,      /* first btree block */
    xfs_da_state_blk_t  *blk2)      /* second btree block */
{
    xfs_da_args_t       *args;      /* operation arguments */
    int         count;      /* count (& direction) leaves */
    int         isleft;     /* new goes in left leaf */
    xfs_dir2_leaf_t     *leaf1;     /* first leaf structure */
    xfs_dir2_leaf_t     *leaf2;     /* second leaf structure */
    int         mid;        /* midpoint leaf index */
#ifdef DEBUG
    int         oldstale;   /* old count of stale leaves */
#endif
    int         oldsum;     /* old total leaf count */
    int         swap;       /* swapped leaf blocks */

    args = state->args;
    /*
     * If the block order is wrong, swap the arguments.
     */
    if ((swap = xfs_dir2_leafn_order(blk1->bp, blk2->bp))) {
        xfs_da_state_blk_t  *tmp;   /* temp for block swap */

        tmp = blk1;
        blk1 = blk2;
        blk2 = tmp;
    }
    leaf1 = blk1->bp->b_addr;
    leaf2 = blk2->bp->b_addr;
    oldsum = be16_to_cpu(leaf1->hdr.count) + be16_to_cpu(leaf2->hdr.count);
#ifdef DEBUG
    oldstale = be16_to_cpu(leaf1->hdr.stale) + be16_to_cpu(leaf2->hdr.stale);
#endif
    mid = oldsum >> 1;
    /*
     * If the old leaf count was odd then the new one will be even,
     * so we need to divide the new count evenly.
     */
    if (oldsum & 1) {
        xfs_dahash_t    midhash;    /* middle entry hash value */

        if (mid >= be16_to_cpu(leaf1->hdr.count))
            midhash = be32_to_cpu(leaf2->ents[mid - be16_to_cpu(leaf1->hdr.count)].hashval);
        else
            midhash = be32_to_cpu(leaf1->ents[mid].hashval);
        isleft = args->hashval <= midhash;
    }
    /*
     * If the old count is even then the new count is odd, so there's
     * no preferred side for the new entry.
     * Pick the left one.
     */
    else
        isleft = 1;
    /*
     * Calculate moved entry count.  Positive means left-to-right,
     * negative means right-to-left.  Then move the entries.
     */
    count = be16_to_cpu(leaf1->hdr.count) - mid + (isleft == 0);
    if (count > 0)
        xfs_dir2_leafn_moveents(args, blk1->bp,
            be16_to_cpu(leaf1->hdr.count) - count, blk2->bp, 0, count);
    else if (count < 0)
        xfs_dir2_leafn_moveents(args, blk2->bp, 0, blk1->bp,
            be16_to_cpu(leaf1->hdr.count), count);
    ASSERT(be16_to_cpu(leaf1->hdr.count) + be16_to_cpu(leaf2->hdr.count) == oldsum);
    ASSERT(be16_to_cpu(leaf1->hdr.stale) + be16_to_cpu(leaf2->hdr.stale) == oldstale);
    /*
     * Mark whether we're inserting into the old or new leaf.
     */
    if (be16_to_cpu(leaf1->hdr.count) < be16_to_cpu(leaf2->hdr.count))
        state->inleaf = swap;
    else if (be16_to_cpu(leaf1->hdr.count) > be16_to_cpu(leaf2->hdr.count))
        state->inleaf = !swap;
    else
        state->inleaf =
            swap ^ (blk1->index <= be16_to_cpu(leaf1->hdr.count));
    /*
     * Adjust the expected index for insertion.
     */
    if (!state->inleaf)
        blk2->index = blk1->index - be16_to_cpu(leaf1->hdr.count);

    /*
     * Finally sanity check just to make sure we are not returning a
     * negative index
     */
    if(blk2->index < 0) {
        state->inleaf = 1;
        blk2->index = 0;
        xfs_alert(args->dp->i_mount,
    "%s: picked the wrong leaf? reverting original leaf: blk1->index %d\n",
            __func__, blk1->index);
    }
}

/*
 * Remove an entry from a node directory.
 * This removes the leaf entry and the data entry,
 * and updates the free block if necessary.
 */
static int                  /* error */
xfs_dir2_leafn_remove(
    xfs_da_args_t       *args,      /* operation arguments */
    struct xfs_buf      *bp,        /* leaf buffer */
    int         index,      /* leaf entry index */
    xfs_da_state_blk_t  *dblk,      /* data block */
    int         *rval)      /* resulting block needs join */
{
    xfs_dir2_data_hdr_t *hdr;       /* data block header */
    xfs_dir2_db_t       db;     /* data block number */
    struct xfs_buf      *dbp;       /* data block buffer */
    xfs_dir2_data_entry_t   *dep;       /* data block entry */
    xfs_inode_t     *dp;        /* incore directory inode */
    xfs_dir2_leaf_t     *leaf;      /* leaf structure */
    xfs_dir2_leaf_entry_t   *lep;       /* leaf entry */
    int         longest;    /* longest data free entry */
    int         off;        /* data block entry offset */
    xfs_mount_t     *mp;        /* filesystem mount point */
    int         needlog;    /* need to log data header */
    int         needscan;   /* need to rescan data frees */
    xfs_trans_t     *tp;        /* transaction pointer */

    trace_xfs_dir2_leafn_remove(args, index);

    dp = args->dp;
    tp = args->trans;
    mp = dp->i_mount;
    leaf = bp->b_addr;
    ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
    /*
     * Point to the entry we're removing.
     */
    lep = &leaf->ents[index];
    /*
     * Extract the data block and offset from the entry.
     */
    db = xfs_dir2_dataptr_to_db(mp, be32_to_cpu(lep->address));
    ASSERT(dblk->blkno == db);
    off = xfs_dir2_dataptr_to_off(mp, be32_to_cpu(lep->address));
    ASSERT(dblk->index == off);
    /*
     * Kill the leaf entry by marking it stale.
     * Log the leaf block changes.
     */
    be16_add_cpu(&leaf->hdr.stale, 1);
    xfs_dir2_leaf_log_header(tp, bp);
    lep->address = cpu_to_be32(XFS_DIR2_NULL_DATAPTR);
    xfs_dir2_leaf_log_ents(tp, bp, index, index);
    /*
     * Make the data entry free.  Keep track of the longest freespace
     * in the data block in case it changes.
     */
    dbp = dblk->bp;
    hdr = dbp->b_addr;
    dep = (xfs_dir2_data_entry_t *)((char *)hdr + off);
    longest = be16_to_cpu(hdr->bestfree[0].length);
    needlog = needscan = 0;
    xfs_dir2_data_make_free(tp, dbp, off,
        xfs_dir2_data_entsize(dep->namelen), &needlog, &needscan);
    /*
     * Rescan the data block freespaces for bestfree.
     * Log the data block header if needed.
     */
    if (needscan)
        xfs_dir2_data_freescan(mp, hdr, &needlog);
    if (needlog)
        xfs_dir2_data_log_header(tp, dbp);
    xfs_dir2_data_check(dp, dbp);
    /*
     * If the longest data block freespace changes, need to update
     * the corresponding freeblock entry.
     */
    if (longest < be16_to_cpu(hdr->bestfree[0].length)) {
        int     error;      /* error return value */
        struct xfs_buf  *fbp;       /* freeblock buffer */
        xfs_dir2_db_t   fdb;        /* freeblock block number */
        int     findex;     /* index in freeblock entries */
        xfs_dir2_free_t *free;      /* freeblock structure */
        int     logfree;    /* need to log free entry */

        /*
         * Convert the data block number to a free block,
         * read in the free block.
         */
        fdb = xfs_dir2_db_to_fdb(mp, db);
        if ((error = xfs_da_read_buf(tp, dp, xfs_dir2_db_to_da(mp, fdb),
                -1, &fbp, XFS_DATA_FORK))) {
            return error;
        }
        free = fbp->b_addr;
        ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC));
        ASSERT(be32_to_cpu(free->hdr.firstdb) ==
               xfs_dir2_free_max_bests(mp) *
               (fdb - XFS_DIR2_FREE_FIRSTDB(mp)));
        /*
         * Calculate which entry we need to fix.
         */
        findex = xfs_dir2_db_to_fdindex(mp, db);
        longest = be16_to_cpu(hdr->bestfree[0].length);
        /*
         * If the data block is now empty we can get rid of it
         * (usually).
         */
        if (longest == mp->m_dirblksize - (uint)sizeof(*hdr)) {
            /*
             * Try to punch out the data block.
             */
            error = xfs_dir2_shrink_inode(args, db, dbp);
            if (error == 0) {
                dblk->bp = NULL;
                hdr = NULL;
            }
            /*
             * We can get ENOSPC if there's no space reservation.
             * In this case just drop the buffer and some one else
             * will eventually get rid of the empty block.
             */
            else if (!(error == ENOSPC && args->total == 0))
                return error;
        }
        /*
         * If we got rid of the data block, we can eliminate that entry
         * in the free block.
         */
        if (hdr == NULL) {
            /*
             * One less used entry in the free table.
             */
            be32_add_cpu(&free->hdr.nused, -1);
            xfs_dir2_free_log_header(tp, fbp);
            /*
             * If this was the last entry in the table, we can
             * trim the table size back.  There might be other
             * entries at the end referring to non-existent
             * data blocks, get those too.
             */
            if (findex == be32_to_cpu(free->hdr.nvalid) - 1) {
                int i;      /* free entry index */

                for (i = findex - 1;
                     i >= 0 &&
                     free->bests[i] == cpu_to_be16(NULLDATAOFF);
                     i--)
                    continue;
                free->hdr.nvalid = cpu_to_be32(i + 1);
                logfree = 0;
            }
            /*
             * Not the last entry, just punch it out.
             */
            else {
                free->bests[findex] = cpu_to_be16(NULLDATAOFF);
                logfree = 1;
            }
            /*
             * If there are no useful entries left in the block,
             * get rid of the block if we can.
             */
            if (!free->hdr.nused) {
                error = xfs_dir2_shrink_inode(args, fdb, fbp);
                if (error == 0) {
                    fbp = NULL;
                    logfree = 0;
                } else if (error != ENOSPC || args->total != 0)
                    return error;
                /*
                 * It's possible to get ENOSPC if there is no
                 * space reservation.  In this case some one
                 * else will eventually get rid of this block.
                 */
            }
        }
        /*
         * Data block is not empty, just set the free entry to
         * the new value.
         */
        else {
            free->bests[findex] = cpu_to_be16(longest);
            logfree = 1;
        }
        /*
         * Log the free entry that changed, unless we got rid of it.
         */
        if (logfree)
            xfs_dir2_free_log_bests(tp, fbp, findex, findex);
    }
    xfs_dir2_leafn_check(dp, bp);
    /*
     * Return indication of whether this leaf block is empty enough
     * to justify trying to join it with a neighbor.
     */
    *rval =
        ((uint)sizeof(leaf->hdr) +
         (uint)sizeof(leaf->ents[0]) *
         (be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale))) <
        mp->m_dir_magicpct;
    return 0;
}

/*
 * Split the leaf entries in the old block into old and new blocks.
 */
int                     /* error */
xfs_dir2_leafn_split(
    xfs_da_state_t      *state,     /* btree cursor */
    xfs_da_state_blk_t  *oldblk,    /* original block */
    xfs_da_state_blk_t  *newblk)    /* newly created block */
{
    xfs_da_args_t       *args;      /* operation arguments */
    xfs_dablk_t     blkno;      /* new leaf block number */
    int         error;      /* error return value */
    xfs_mount_t     *mp;        /* filesystem mount point */

    /*
     * Allocate space for a new leaf node.
     */
    args = state->args;
    mp = args->dp->i_mount;
    ASSERT(args != NULL);
    ASSERT(oldblk->magic == XFS_DIR2_LEAFN_MAGIC);
    error = xfs_da_grow_inode(args, &blkno);
    if (error) {
        return error;
    }
    /*
     * Initialize the new leaf block.
     */
    error = xfs_dir2_leaf_init(args, xfs_dir2_da_to_db(mp, blkno),
        &newblk->bp, XFS_DIR2_LEAFN_MAGIC);
    if (error) {
        return error;
    }
    newblk->blkno = blkno;
    newblk->magic = XFS_DIR2_LEAFN_MAGIC;
    /*
     * Rebalance the entries across the two leaves, link the new
     * block into the leaves.
     */
    xfs_dir2_leafn_rebalance(state, oldblk, newblk);
    error = xfs_da_blk_link(state, oldblk, newblk);
    if (error) {
        return error;
    }
    /*
     * Insert the new entry in the correct block.
     */
    if (state->inleaf)
        error = xfs_dir2_leafn_add(oldblk->bp, args, oldblk->index);
    else
        error = xfs_dir2_leafn_add(newblk->bp, args, newblk->index);
    /*
     * Update last hashval in each block since we added the name.
     */
    oldblk->hashval = xfs_dir2_leafn_lasthash(oldblk->bp, NULL);
    newblk->hashval = xfs_dir2_leafn_lasthash(newblk->bp, NULL);
    xfs_dir2_leafn_check(args->dp, oldblk->bp);
    xfs_dir2_leafn_check(args->dp, newblk->bp);
    return error;
}

/*
 * Check a leaf block and its neighbors to see if the block should be
 * collapsed into one or the other neighbor.  Always keep the block
 * with the smaller block number.
 * If the current block is over 50% full, don't try to join it, return 0.
 * If the block is empty, fill in the state structure and return 2.
 * If it can be collapsed, fill in the state structure and return 1.
 * If nothing can be done, return 0.
 */
int                     /* error */
xfs_dir2_leafn_toosmall(
    xfs_da_state_t      *state,     /* btree cursor */
    int         *action)    /* resulting action to take */
{
    xfs_da_state_blk_t  *blk;       /* leaf block */
    xfs_dablk_t     blkno;      /* leaf block number */
    struct xfs_buf      *bp;        /* leaf buffer */
    int         bytes;      /* bytes in use */
    int         count;      /* leaf live entry count */
    int         error;      /* error return value */
    int         forward;    /* sibling block direction */
    int         i;      /* sibling counter */
    xfs_da_blkinfo_t    *info;      /* leaf block header */
    xfs_dir2_leaf_t     *leaf;      /* leaf structure */
    int         rval;       /* result from path_shift */

    /*
     * Check for the degenerate case of the block being over 50% full.
     * If so, it's not worth even looking to see if we might be able
     * to coalesce with a sibling.
     */
    blk = &state->path.blk[state->path.active - 1];
    info = blk->bp->b_addr;
    ASSERT(info->magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
    leaf = (xfs_dir2_leaf_t *)info;
    count = be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale);
    bytes = (uint)sizeof(leaf->hdr) + count * (uint)sizeof(leaf->ents[0]);
    if (bytes > (state->blocksize >> 1)) {
        /*
         * Blk over 50%, don't try to join.
         */
        *action = 0;
        return 0;
    }
    /*
     * Check for the degenerate case of the block being empty.
     * If the block is empty, we'll simply delete it, no need to
     * coalesce it with a sibling block.  We choose (arbitrarily)
     * to merge with the forward block unless it is NULL.
     */
    if (count == 0) {
        /*
         * Make altpath point to the block we want to keep and
         * path point to the block we want to drop (this one).
         */
        forward = (info->forw != 0);
        memcpy(&state->altpath, &state->path, sizeof(state->path));
        error = xfs_da_path_shift(state, &state->altpath, forward, 0,
            &rval);
        if (error)
            return error;
        *action = rval ? 2 : 0;
        return 0;
    }
    /*
     * Examine each sibling block to see if we can coalesce with
     * at least 25% free space to spare.  We need to figure out
     * whether to merge with the forward or the backward block.
     * We prefer coalescing with the lower numbered sibling so as
     * to shrink a directory over time.
     */
    forward = be32_to_cpu(info->forw) < be32_to_cpu(info->back);
    for (i = 0, bp = NULL; i < 2; forward = !forward, i++) {
        blkno = forward ? be32_to_cpu(info->forw) : be32_to_cpu(info->back);
        if (blkno == 0)
            continue;
        /*
         * Read the sibling leaf block.
         */
        if ((error =
            xfs_da_read_buf(state->args->trans, state->args->dp, blkno,
                -1, &bp, XFS_DATA_FORK))) {
            return error;
        }
        ASSERT(bp != NULL);
        /*
         * Count bytes in the two blocks combined.
         */
        leaf = (xfs_dir2_leaf_t *)info;
        count = be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale);
        bytes = state->blocksize - (state->blocksize >> 2);
        leaf = bp->b_addr;
        ASSERT(leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
        count += be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale);
        bytes -= count * (uint)sizeof(leaf->ents[0]);
        /*
         * Fits with at least 25% to spare.
         */
        if (bytes >= 0)
            break;
        xfs_trans_brelse(state->args->trans, bp);
    }
    /*
     * Didn't like either block, give up.
     */
    if (i >= 2) {
        *action = 0;
        return 0;
    }

    /*
     * Make altpath point to the block we want to keep (the lower
     * numbered block) and path point to the block we want to drop.
     */
    memcpy(&state->altpath, &state->path, sizeof(state->path));
    if (blkno < blk->blkno)
        error = xfs_da_path_shift(state, &state->altpath, forward, 0,
            &rval);
    else
        error = xfs_da_path_shift(state, &state->path, forward, 0,
            &rval);
    if (error) {
        return error;
    }
    *action = rval ? 0 : 1;
    return 0;
}

/*
 * Move all the leaf entries from drop_blk to save_blk.
 * This is done as part of a join operation.
 */
void
xfs_dir2_leafn_unbalance(
    xfs_da_state_t      *state,     /* cursor */
    xfs_da_state_blk_t  *drop_blk,  /* dead block */
    xfs_da_state_blk_t  *save_blk)  /* surviving block */
{
    xfs_da_args_t       *args;      /* operation arguments */
    xfs_dir2_leaf_t     *drop_leaf; /* dead leaf structure */
    xfs_dir2_leaf_t     *save_leaf; /* surviving leaf structure */

    args = state->args;
    ASSERT(drop_blk->magic == XFS_DIR2_LEAFN_MAGIC);
    ASSERT(save_blk->magic == XFS_DIR2_LEAFN_MAGIC);
    drop_leaf = drop_blk->bp->b_addr;
    save_leaf = save_blk->bp->b_addr;
    ASSERT(drop_leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
    ASSERT(save_leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC));
    /*
     * If there are any stale leaf entries, take this opportunity
     * to purge them.
     */
    if (drop_leaf->hdr.stale)
        xfs_dir2_leaf_compact(args, drop_blk->bp);
    if (save_leaf->hdr.stale)
        xfs_dir2_leaf_compact(args, save_blk->bp);
    /*
     * Move the entries from drop to the appropriate end of save.
     */
    drop_blk->hashval = be32_to_cpu(drop_leaf->ents[be16_to_cpu(drop_leaf->hdr.count) - 1].hashval);
    if (xfs_dir2_leafn_order(save_blk->bp, drop_blk->bp))
        xfs_dir2_leafn_moveents(args, drop_blk->bp, 0, save_blk->bp, 0,
            be16_to_cpu(drop_leaf->hdr.count));
    else
        xfs_dir2_leafn_moveents(args, drop_blk->bp, 0, save_blk->bp,
            be16_to_cpu(save_leaf->hdr.count), be16_to_cpu(drop_leaf->hdr.count));
    save_blk->hashval = be32_to_cpu(save_leaf->ents[be16_to_cpu(save_leaf->hdr.count) - 1].hashval);
    xfs_dir2_leafn_check(args->dp, save_blk->bp);
}

/*
 * Top-level node form directory addname routine.
 */
int                     /* error */
xfs_dir2_node_addname(
    xfs_da_args_t       *args)      /* operation arguments */
{
    xfs_da_state_blk_t  *blk;       /* leaf block for insert */
    int         error;      /* error return value */
    int         rval;       /* sub-return value */
    xfs_da_state_t      *state;     /* btree cursor */

    trace_xfs_dir2_node_addname(args);

    /*
     * Allocate and initialize the state (btree cursor).
     */
    state = xfs_da_state_alloc();
    state->args = args;
    state->mp = args->dp->i_mount;
    state->blocksize = state->mp->m_dirblksize;
    state->node_ents = state->mp->m_dir_node_ents;
    /*
     * Look up the name.  We're not supposed to find it, but
     * this gives us the insertion point.
     */
    error = xfs_da_node_lookup_int(state, &rval);
    if (error)
        rval = error;
    if (rval != ENOENT) {
        goto done;
    }
    /*
     * Add the data entry to a data block.
     * Extravalid is set to a freeblock found by lookup.
     */
    rval = xfs_dir2_node_addname_int(args,
        state->extravalid ? &state->extrablk : NULL);
    if (rval) {
        goto done;
    }
    blk = &state->path.blk[state->path.active - 1];
    ASSERT(blk->magic == XFS_DIR2_LEAFN_MAGIC);
    /*
     * Add the new leaf entry.
     */
    rval = xfs_dir2_leafn_add(blk->bp, args, blk->index);
    if (rval == 0) {
        /*
         * It worked, fix the hash values up the btree.
         */
        if (!(args->op_flags & XFS_DA_OP_JUSTCHECK))
            xfs_da_fixhashpath(state, &state->path);
    } else {
        /*
         * It didn't work, we need to split the leaf block.
         */
        if (args->total == 0) {
            ASSERT(rval == ENOSPC);
            goto done;
        }
        /*
         * Split the leaf block and insert the new entry.
         */
        rval = xfs_da_split(state);
    }
done:
    xfs_da_state_free(state);
    return rval;
}

/*
 * Add the data entry for a node-format directory name addition.
 * The leaf entry is added in xfs_dir2_leafn_add.
 * We may enter with a freespace block that the lookup found.
 */
static int                  /* error */
xfs_dir2_node_addname_int(
    xfs_da_args_t       *args,      /* operation arguments */
    xfs_da_state_blk_t  *fblk)      /* optional freespace block */
{
    xfs_dir2_data_hdr_t *hdr;       /* data block header */
    xfs_dir2_db_t       dbno;       /* data block number */
    struct xfs_buf      *dbp;       /* data block buffer */
    xfs_dir2_data_entry_t   *dep;       /* data entry pointer */
    xfs_inode_t     *dp;        /* incore directory inode */
    xfs_dir2_data_unused_t  *dup;       /* data unused entry pointer */
    int         error;      /* error return value */
    xfs_dir2_db_t       fbno;       /* freespace block number */
    struct xfs_buf      *fbp;       /* freespace buffer */
    int         findex;     /* freespace entry index */
    xfs_dir2_free_t     *free=NULL; /* freespace block structure */
    xfs_dir2_db_t       ifbno;      /* initial freespace block no */
    xfs_dir2_db_t       lastfbno=0; /* highest freespace block no */
    int         length;     /* length of the new entry */
    int         logfree;    /* need to log free entry */
    xfs_mount_t     *mp;        /* filesystem mount point */
    int         needlog;    /* need to log data header */
    int         needscan;   /* need to rescan data frees */
    __be16          *tagp;      /* data entry tag pointer */
    xfs_trans_t     *tp;        /* transaction pointer */

    dp = args->dp;
    mp = dp->i_mount;
    tp = args->trans;
    length = xfs_dir2_data_entsize(args->namelen);
    /*
     * If we came in with a freespace block that means that lookup
     * found an entry with our hash value.  This is the freespace
     * block for that data entry.
     */
    if (fblk) {
        fbp = fblk->bp;
        /*
         * Remember initial freespace block number.
         */
        ifbno = fblk->blkno;
        free = fbp->b_addr;
        ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC));
        findex = fblk->index;
        /*
         * This means the free entry showed that the data block had
         * space for our entry, so we remembered it.
         * Use that data block.
         */
        if (findex >= 0) {
            ASSERT(findex < be32_to_cpu(free->hdr.nvalid));
            ASSERT(be16_to_cpu(free->bests[findex]) != NULLDATAOFF);
            ASSERT(be16_to_cpu(free->bests[findex]) >= length);
            dbno = be32_to_cpu(free->hdr.firstdb) + findex;
        }
        /*
         * The data block looked at didn't have enough room.
         * We'll start at the beginning of the freespace entries.
         */
        else {
            dbno = -1;
            findex = 0;
        }
    }
    /*
     * Didn't come in with a freespace block, so don't have a data block.
     */
    else {
        ifbno = dbno = -1;
        fbp = NULL;
        findex = 0;
    }
    /*
     * If we don't have a data block yet, we're going to scan the
     * freespace blocks looking for one.  Figure out what the
     * highest freespace block number is.
     */
    if (dbno == -1) {
        xfs_fileoff_t   fo;     /* freespace block number */

        if ((error = xfs_bmap_last_offset(tp, dp, &fo, XFS_DATA_FORK)))
            return error;
        lastfbno = xfs_dir2_da_to_db(mp, (xfs_dablk_t)fo);
        fbno = ifbno;
    }
    /*
     * While we haven't identified a data block, search the freeblock
     * data for a good data block.  If we find a null freeblock entry,
     * indicating a hole in the data blocks, remember that.
     */
    while (dbno == -1) {
        /*
         * If we don't have a freeblock in hand, get the next one.
         */
        if (fbp == NULL) {
            /*
             * Happens the first time through unless lookup gave
             * us a freespace block to start with.
             */
            if (++fbno == 0)
                fbno = XFS_DIR2_FREE_FIRSTDB(mp);
            /*
             * If it's ifbno we already looked at it.
             */
            if (fbno == ifbno)
                fbno++;
            /*
             * If it's off the end we're done.
             */
            if (fbno >= lastfbno)
                break;
            /*
             * Read the block.  There can be holes in the
             * freespace blocks, so this might not succeed.
             * This should be really rare, so there's no reason
             * to avoid it.
             */
            if ((error = xfs_da_read_buf(tp, dp,
                    xfs_dir2_db_to_da(mp, fbno), -2, &fbp,
                    XFS_DATA_FORK))) {
                return error;
            }
            if (unlikely(fbp == NULL)) {
                continue;
            }
            free = fbp->b_addr;
            ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC));
            findex = 0;
        }
        /*
         * Look at the current free entry.  Is it good enough?
         */
        if (be16_to_cpu(free->bests[findex]) != NULLDATAOFF &&
            be16_to_cpu(free->bests[findex]) >= length)
            dbno = be32_to_cpu(free->hdr.firstdb) + findex;
        else {
            /*
             * Are we done with the freeblock?
             */
            if (++findex == be32_to_cpu(free->hdr.nvalid)) {
                /*
                 * Drop the block.
                 */
                xfs_trans_brelse(tp, fbp);
                fbp = NULL;
                if (fblk && fblk->bp)
                    fblk->bp = NULL;
            }
        }
    }
    /*
     * If we don't have a data block, we need to allocate one and make
     * the freespace entries refer to it.
     */
    if (unlikely(dbno == -1)) {
        /*
         * Not allowed to allocate, return failure.
         */
        if ((args->op_flags & XFS_DA_OP_JUSTCHECK) || args->total == 0)
            return XFS_ERROR(ENOSPC);

        /*
         * Allocate and initialize the new data block.
         */
        if (unlikely((error = xfs_dir2_grow_inode(args,
                             XFS_DIR2_DATA_SPACE,
                             &dbno)) ||
            (error = xfs_dir2_data_init(args, dbno, &dbp))))
            return error;

        /*
         * If (somehow) we have a freespace block, get rid of it.
         */
        if (fbp)
            xfs_trans_brelse(tp, fbp);
        if (fblk && fblk->bp)
            fblk->bp = NULL;

        /*
         * Get the freespace block corresponding to the data block
         * that was just allocated.
         */
        fbno = xfs_dir2_db_to_fdb(mp, dbno);
        if (unlikely(error = xfs_da_read_buf(tp, dp,
                xfs_dir2_db_to_da(mp, fbno), -2, &fbp,
                XFS_DATA_FORK)))
            return error;

        /*
         * If there wasn't a freespace block, the read will
         * return a NULL fbp.  Allocate and initialize a new one.
         */
        if( fbp == NULL ) {
            if ((error = xfs_dir2_grow_inode(args, XFS_DIR2_FREE_SPACE,
                            &fbno))) {
                return error;
            }

            if (unlikely(xfs_dir2_db_to_fdb(mp, dbno) != fbno)) {
                xfs_alert(mp,
            "%s: dir ino %llu needed freesp block %lld for\n"
            "  data block %lld, got %lld ifbno %llu lastfbno %d",
                    __func__, (unsigned long long)dp->i_ino,
                    (long long)xfs_dir2_db_to_fdb(mp, dbno),
                    (long long)dbno, (long long)fbno,
                    (unsigned long long)ifbno, lastfbno);
                if (fblk) {
                    xfs_alert(mp,
                " fblk 0x%p blkno %llu index %d magic 0x%x",
                        fblk,
                        (unsigned long long)fblk->blkno,
                        fblk->index,
                        fblk->magic);
                } else {
                    xfs_alert(mp, " ... fblk is NULL");
                }
                XFS_ERROR_REPORT("xfs_dir2_node_addname_int",
                         XFS_ERRLEVEL_LOW, mp);
                return XFS_ERROR(EFSCORRUPTED);
            }

            /*
             * Get a buffer for the new block.
             */
            if ((error = xfs_da_get_buf(tp, dp,
                           xfs_dir2_db_to_da(mp, fbno),
                           -1, &fbp, XFS_DATA_FORK))) {
                return error;
            }
            ASSERT(fbp != NULL);

            /*
             * Initialize the new block to be empty, and remember
             * its first slot as our empty slot.
             */
            free = fbp->b_addr;
            free->hdr.magic = cpu_to_be32(XFS_DIR2_FREE_MAGIC);
            free->hdr.firstdb = cpu_to_be32(
                (fbno - XFS_DIR2_FREE_FIRSTDB(mp)) *
                xfs_dir2_free_max_bests(mp));
            free->hdr.nvalid = 0;
            free->hdr.nused = 0;
        } else {
            free = fbp->b_addr;
            ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC));
        }

        /*
         * Set the freespace block index from the data block number.
         */
        findex = xfs_dir2_db_to_fdindex(mp, dbno);
        /*
         * If it's after the end of the current entries in the
         * freespace block, extend that table.
         */
        if (findex >= be32_to_cpu(free->hdr.nvalid)) {
            ASSERT(findex < xfs_dir2_free_max_bests(mp));
            free->hdr.nvalid = cpu_to_be32(findex + 1);
            /*
             * Tag new entry so nused will go up.
             */
            free->bests[findex] = cpu_to_be16(NULLDATAOFF);
        }
        /*
         * If this entry was for an empty data block
         * (this should always be true) then update the header.
         */
        if (free->bests[findex] == cpu_to_be16(NULLDATAOFF)) {
            be32_add_cpu(&free->hdr.nused, 1);
            xfs_dir2_free_log_header(tp, fbp);
        }
        /*
         * Update the real value in the table.
         * We haven't allocated the data entry yet so this will
         * change again.
         */
        hdr = dbp->b_addr;
        free->bests[findex] = hdr->bestfree[0].length;
        logfree = 1;
    }
    /*
     * We had a data block so we don't have to make a new one.
     */
    else {
        /*
         * If just checking, we succeeded.
         */
        if (args->op_flags & XFS_DA_OP_JUSTCHECK)
            return 0;

        /*
         * Read the data block in.
         */
        error = xfs_da_read_buf(tp, dp, xfs_dir2_db_to_da(mp, dbno),
                -1, &dbp, XFS_DATA_FORK);
        if (error)
            return error;
        hdr = dbp->b_addr;
        logfree = 0;
    }
    ASSERT(be16_to_cpu(hdr->bestfree[0].length) >= length);
    /*
     * Point to the existing unused space.
     */
    dup = (xfs_dir2_data_unused_t *)
          ((char *)hdr + be16_to_cpu(hdr->bestfree[0].offset));
    needscan = needlog = 0;
    /*
     * Mark the first part of the unused space, inuse for us.
     */
    xfs_dir2_data_use_free(tp, dbp, dup,
        (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr), length,
        &needlog, &needscan);
    /*
     * Fill in the new entry and log it.
     */
    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);
    xfs_dir2_data_log_entry(tp, dbp, dep);
    /*
     * Rescan the block for bestfree if needed.
     */
    if (needscan)
        xfs_dir2_data_freescan(mp, hdr, &needlog);
    /*
     * Log the data block header if needed.
     */
    if (needlog)
        xfs_dir2_data_log_header(tp, dbp);
    /*
     * If the freespace entry is now wrong, update it.
     */
    if (be16_to_cpu(free->bests[findex]) != be16_to_cpu(hdr->bestfree[0].length)) {
        free->bests[findex] = hdr->bestfree[0].length;
        logfree = 1;
    }
    /*
     * Log the freespace entry if needed.
     */
    if (logfree)
        xfs_dir2_free_log_bests(tp, fbp, findex, findex);
    /*
     * Return the data block and offset in args, then drop the data block.
     */
    args->blkno = (xfs_dablk_t)dbno;
    args->index = be16_to_cpu(*tagp);
    return 0;
}

/*
 * Lookup an entry in a node-format directory.
 * All the real work happens in xfs_da_node_lookup_int.
 * The only real output is the inode number of the entry.
 */
int                     /* error */
xfs_dir2_node_lookup(
    xfs_da_args_t   *args)          /* operation arguments */
{
    int     error;          /* error return value */
    int     i;          /* btree level */
    int     rval;           /* operation return value */
    xfs_da_state_t  *state;         /* btree cursor */

    trace_xfs_dir2_node_lookup(args);

    /*
     * Allocate and initialize the btree cursor.
     */
    state = xfs_da_state_alloc();
    state->args = args;
    state->mp = args->dp->i_mount;
    state->blocksize = state->mp->m_dirblksize;
    state->node_ents = state->mp->m_dir_node_ents;
    /*
     * Fill in the path to the entry in the cursor.
     */
    error = xfs_da_node_lookup_int(state, &rval);
    if (error)
        rval = error;
    else if (rval == ENOENT && args->cmpresult == XFS_CMP_CASE) {
        /* If a CI match, dup the actual name and return EEXIST */
        xfs_dir2_data_entry_t   *dep;

        dep = (xfs_dir2_data_entry_t *)
            ((char *)state->extrablk.bp->b_addr +
                         state->extrablk.index);
        rval = xfs_dir_cilookup_result(args, dep->name, dep->namelen);
    }
    /*
     * Release the btree blocks and leaf block.
     */
    for (i = 0; i < state->path.active; i++) {
        xfs_trans_brelse(args->trans, state->path.blk[i].bp);
        state->path.blk[i].bp = NULL;
    }
    /*
     * Release the data block if we have it.
     */
    if (state->extravalid && state->extrablk.bp) {
        xfs_trans_brelse(args->trans, state->extrablk.bp);
        state->extrablk.bp = NULL;
    }
    xfs_da_state_free(state);
    return rval;
}

/*
 * Remove an entry from a node-format directory.
 */
int                     /* error */
xfs_dir2_node_removename(
    xfs_da_args_t       *args)      /* operation arguments */
{
    xfs_da_state_blk_t  *blk;       /* leaf block */
    int         error;      /* error return value */
    int         rval;       /* operation return value */
    xfs_da_state_t      *state;     /* btree cursor */

    trace_xfs_dir2_node_removename(args);

    /*
     * Allocate and initialize the btree cursor.
     */
    state = xfs_da_state_alloc();
    state->args = args;
    state->mp = args->dp->i_mount;
    state->blocksize = state->mp->m_dirblksize;
    state->node_ents = state->mp->m_dir_node_ents;
    /*
     * Look up the entry we're deleting, set up the cursor.
     */
    error = xfs_da_node_lookup_int(state, &rval);
    if (error)
        rval = error;
    /*
     * Didn't find it, upper layer screwed up.
     */
    if (rval != EEXIST) {
        xfs_da_state_free(state);
        return rval;
    }
    blk = &state->path.blk[state->path.active - 1];
    ASSERT(blk->magic == XFS_DIR2_LEAFN_MAGIC);
    ASSERT(state->extravalid);
    /*
     * Remove the leaf and data entries.
     * Extrablk refers to the data block.
     */
    error = xfs_dir2_leafn_remove(args, blk->bp, blk->index,
        &state->extrablk, &rval);
    if (error)
        return error;
    /*
     * Fix the hash values up the btree.
     */
    xfs_da_fixhashpath(state, &state->path);
    /*
     * If we need to join leaf blocks, do it.
     */
    if (rval && state->path.active > 1)
        error = xfs_da_join(state);
    /*
     * If no errors so far, try conversion to leaf format.
     */
    if (!error)
        error = xfs_dir2_node_to_leaf(state);
    xfs_da_state_free(state);
    return error;
}

/*
 * Replace an entry's inode number in a node-format directory.
 */
int                     /* error */
xfs_dir2_node_replace(
    xfs_da_args_t       *args)      /* operation arguments */
{
    xfs_da_state_blk_t  *blk;       /* leaf block */
    xfs_dir2_data_hdr_t *hdr;       /* data block header */
    xfs_dir2_data_entry_t   *dep;       /* data entry changed */
    int         error;      /* error return value */
    int         i;      /* btree level */
    xfs_ino_t       inum;       /* new inode number */
    xfs_dir2_leaf_t     *leaf;      /* leaf structure */
    xfs_dir2_leaf_entry_t   *lep;       /* leaf entry being changed */
    int         rval;       /* internal return value */
    xfs_da_state_t      *state;     /* btree cursor */

    trace_xfs_dir2_node_replace(args);

    /*
     * Allocate and initialize the btree cursor.
     */
    state = xfs_da_state_alloc();
    state->args = args;
    state->mp = args->dp->i_mount;
    state->blocksize = state->mp->m_dirblksize;
    state->node_ents = state->mp->m_dir_node_ents;
    inum = args->inumber;
    /*
     * Lookup the entry to change in the btree.
     */
    error = xfs_da_node_lookup_int(state, &rval);
    if (error) {
        rval = error;
    }
    /*
     * It should be found, since the vnodeops layer has looked it up
     * and locked it.  But paranoia is good.
     */
    if (rval == EEXIST) {
        /*
         * Find the leaf entry.
         */
        blk = &state->path.blk[state->path.active - 1];
        ASSERT(blk->magic == XFS_DIR2_LEAFN_MAGIC);
        leaf = blk->bp->b_addr;
        lep = &leaf->ents[blk->index];
        ASSERT(state->extravalid);
        /*
         * Point to the data entry.
         */
        hdr = state->extrablk.bp->b_addr;
        ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC));
        dep = (xfs_dir2_data_entry_t *)
              ((char *)hdr +
               xfs_dir2_dataptr_to_off(state->mp, be32_to_cpu(lep->address)));
        ASSERT(inum != be64_to_cpu(dep->inumber));
        /*
         * Fill in the new inode number and log the entry.
         */
        dep->inumber = cpu_to_be64(inum);
        xfs_dir2_data_log_entry(args->trans, state->extrablk.bp, dep);
        rval = 0;
    }
    /*
     * Didn't find it, and we're holding a data block.  Drop it.
     */
    else if (state->extravalid) {
        xfs_trans_brelse(args->trans, state->extrablk.bp);
        state->extrablk.bp = NULL;
    }
    /*
     * Release all the buffers in the cursor.
     */
    for (i = 0; i < state->path.active; i++) {
        xfs_trans_brelse(args->trans, state->path.blk[i].bp);
        state->path.blk[i].bp = NULL;
    }
    xfs_da_state_free(state);
    return rval;
}

/*
 * Trim off a trailing empty freespace block.
 * Return (in rvalp) 1 if we did it, 0 if not.
 */
int                     /* error */
xfs_dir2_node_trim_free(
    xfs_da_args_t       *args,      /* operation arguments */
    xfs_fileoff_t       fo,     /* free block number */
    int         *rvalp)     /* out: did something */
{
    struct xfs_buf      *bp;        /* freespace buffer */
    xfs_inode_t     *dp;        /* incore directory inode */
    int         error;      /* error return code */
    xfs_dir2_free_t     *free;      /* freespace 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 freespace block.
     */
    if (unlikely(error = xfs_da_read_buf(tp, dp, (xfs_dablk_t)fo, -2, &bp,
            XFS_DATA_FORK))) {
        return error;
    }

    /*
     * There can be holes in freespace.  If fo is a hole, there's
     * nothing to do.
     */
    if (bp == NULL) {
        return 0;
    }
    free = bp->b_addr;
    ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC));
    /*
     * If there are used entries, there's nothing to do.
     */
    if (be32_to_cpu(free->hdr.nused) > 0) {
        xfs_trans_brelse(tp, bp);
        *rvalp = 0;
        return 0;
    }
    /*
     * Blow the block away.
     */
    if ((error =
        xfs_dir2_shrink_inode(args, xfs_dir2_da_to_db(mp, (xfs_dablk_t)fo),
            bp))) {
        /*
         * Can't fail with ENOSPC since that only happens with no
         * space reservation, when breaking up an extent into two
         * pieces.  This is the last block of an extent.
         */
        ASSERT(error != ENOSPC);
        xfs_trans_brelse(tp, bp);
        return error;
    }
    /*
     * Return that we succeeded.
     */
    *rvalp = 1;
    return 0;
}