WIP FPC-III support

[linux/fpc-iii.git] / fs / xfs / libxfs / xfs_dir2_node.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * Copyright (c) 2013 Red Hat, Inc.
 * All Rights Reserved.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_bmap.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_error.h"
#include "xfs_trace.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_log.h"

/*
 * Function declarations.
 */
static int xfs_dir2_leafn_add(struct xfs_buf *bp, xfs_da_args_t *args,
                              int index);
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);

/*
 * Convert data space db to the corresponding free db.
 */
static xfs_dir2_db_t
xfs_dir2_db_to_fdb(struct xfs_da_geometry *geo, xfs_dir2_db_t db)
{
        return xfs_dir2_byte_to_db(geo, XFS_DIR2_FREE_OFFSET) +
                        (db / geo->free_max_bests);
}

/*
 * Convert data space db to the corresponding index in a free db.
 */
static int
xfs_dir2_db_to_fdindex(struct xfs_da_geometry *geo, xfs_dir2_db_t db)
{
        return db % geo->free_max_bests;
}

/*
 * Check internal consistency of a leafn block.
 */
#ifdef DEBUG
static xfs_failaddr_t
xfs_dir3_leafn_check(
        struct xfs_inode        *dp,
        struct xfs_buf          *bp)
{
        struct xfs_dir2_leaf    *leaf = bp->b_addr;
        struct xfs_dir3_icleaf_hdr leafhdr;

        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &leafhdr, leaf);

        if (leafhdr.magic == XFS_DIR3_LEAFN_MAGIC) {
                struct xfs_dir3_leaf_hdr *leaf3 = bp->b_addr;
                if (be64_to_cpu(leaf3->info.blkno) != bp->b_bn)
                        return __this_address;
        } else if (leafhdr.magic != XFS_DIR2_LEAFN_MAGIC)
                return __this_address;

        return xfs_dir3_leaf_check_int(dp->i_mount, &leafhdr, leaf);
}

static inline void
xfs_dir3_leaf_check(
        struct xfs_inode        *dp,
        struct xfs_buf          *bp)
{
        xfs_failaddr_t          fa;

        fa = xfs_dir3_leafn_check(dp, bp);
        if (!fa)
                return;
        xfs_corruption_error(__func__, XFS_ERRLEVEL_LOW, dp->i_mount,
                        bp->b_addr, BBTOB(bp->b_length), __FILE__, __LINE__,
                        fa);
        ASSERT(0);
}
#else
#define xfs_dir3_leaf_check(dp, bp)
#endif

static xfs_failaddr_t
xfs_dir3_free_verify(
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = bp->b_mount;
        struct xfs_dir2_free_hdr *hdr = bp->b_addr;

        if (!xfs_verify_magic(bp, hdr->magic))
                return __this_address;

        if (xfs_sb_version_hascrc(&mp->m_sb)) {
                struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;

                if (!uuid_equal(&hdr3->uuid, &mp->m_sb.sb_meta_uuid))
                        return __this_address;
                if (be64_to_cpu(hdr3->blkno) != bp->b_bn)
                        return __this_address;
                if (!xfs_log_check_lsn(mp, be64_to_cpu(hdr3->lsn)))
                        return __this_address;
        }

        /* XXX: should bounds check the xfs_dir3_icfree_hdr here */

        return NULL;
}

static void
xfs_dir3_free_read_verify(
        struct xfs_buf  *bp)
{
        struct xfs_mount        *mp = bp->b_mount;
        xfs_failaddr_t          fa;

        if (xfs_sb_version_hascrc(&mp->m_sb) &&
            !xfs_buf_verify_cksum(bp, XFS_DIR3_FREE_CRC_OFF))
                xfs_verifier_error(bp, -EFSBADCRC, __this_address);
        else {
                fa = xfs_dir3_free_verify(bp);
                if (fa)
                        xfs_verifier_error(bp, -EFSCORRUPTED, fa);
        }
}

static void
xfs_dir3_free_write_verify(
        struct xfs_buf  *bp)
{
        struct xfs_mount        *mp = bp->b_mount;
        struct xfs_buf_log_item *bip = bp->b_log_item;
        struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
        xfs_failaddr_t          fa;

        fa = xfs_dir3_free_verify(bp);
        if (fa) {
                xfs_verifier_error(bp, -EFSCORRUPTED, fa);
                return;
        }

        if (!xfs_sb_version_hascrc(&mp->m_sb))
                return;

        if (bip)
                hdr3->lsn = cpu_to_be64(bip->bli_item.li_lsn);

        xfs_buf_update_cksum(bp, XFS_DIR3_FREE_CRC_OFF);
}

const struct xfs_buf_ops xfs_dir3_free_buf_ops = {
        .name = "xfs_dir3_free",
        .magic = { cpu_to_be32(XFS_DIR2_FREE_MAGIC),
                   cpu_to_be32(XFS_DIR3_FREE_MAGIC) },
        .verify_read = xfs_dir3_free_read_verify,
        .verify_write = xfs_dir3_free_write_verify,
        .verify_struct = xfs_dir3_free_verify,
};

/* Everything ok in the free block header? */
static xfs_failaddr_t
xfs_dir3_free_header_check(
        struct xfs_inode        *dp,
        xfs_dablk_t             fbno,
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = dp->i_mount;
        int                     maxbests = mp->m_dir_geo->free_max_bests;
        unsigned int            firstdb;

        firstdb = (xfs_dir2_da_to_db(mp->m_dir_geo, fbno) -
                   xfs_dir2_byte_to_db(mp->m_dir_geo, XFS_DIR2_FREE_OFFSET)) *
                        maxbests;
        if (xfs_sb_version_hascrc(&mp->m_sb)) {
                struct xfs_dir3_free_hdr *hdr3 = bp->b_addr;

                if (be32_to_cpu(hdr3->firstdb) != firstdb)
                        return __this_address;
                if (be32_to_cpu(hdr3->nvalid) > maxbests)
                        return __this_address;
                if (be32_to_cpu(hdr3->nvalid) < be32_to_cpu(hdr3->nused))
                        return __this_address;
                if (be64_to_cpu(hdr3->hdr.owner) != dp->i_ino)
                        return __this_address;
        } else {
                struct xfs_dir2_free_hdr *hdr = bp->b_addr;

                if (be32_to_cpu(hdr->firstdb) != firstdb)
                        return __this_address;
                if (be32_to_cpu(hdr->nvalid) > maxbests)
                        return __this_address;
                if (be32_to_cpu(hdr->nvalid) < be32_to_cpu(hdr->nused))
                        return __this_address;
        }
        return NULL;
}

static int
__xfs_dir3_free_read(
        struct xfs_trans        *tp,
        struct xfs_inode        *dp,
        xfs_dablk_t             fbno,
        unsigned int            flags,
        struct xfs_buf          **bpp)
{
        xfs_failaddr_t          fa;
        int                     err;

        err = xfs_da_read_buf(tp, dp, fbno, flags, bpp, XFS_DATA_FORK,
                        &xfs_dir3_free_buf_ops);
        if (err || !*bpp)
                return err;

        /* Check things that we can't do in the verifier. */
        fa = xfs_dir3_free_header_check(dp, fbno, *bpp);
        if (fa) {
                __xfs_buf_mark_corrupt(*bpp, fa);
                xfs_trans_brelse(tp, *bpp);
                *bpp = NULL;
                return -EFSCORRUPTED;
        }

        /* try read returns without an error or *bpp if it lands in a hole */
        if (tp)
                xfs_trans_buf_set_type(tp, *bpp, XFS_BLFT_DIR_FREE_BUF);

        return 0;
}

void
xfs_dir2_free_hdr_from_disk(
        struct xfs_mount                *mp,
        struct xfs_dir3_icfree_hdr      *to,
        struct xfs_dir2_free            *from)
{
        if (xfs_sb_version_hascrc(&mp->m_sb)) {
                struct xfs_dir3_free    *from3 = (struct xfs_dir3_free *)from;

                to->magic = be32_to_cpu(from3->hdr.hdr.magic);
                to->firstdb = be32_to_cpu(from3->hdr.firstdb);
                to->nvalid = be32_to_cpu(from3->hdr.nvalid);
                to->nused = be32_to_cpu(from3->hdr.nused);
                to->bests = from3->bests;

                ASSERT(to->magic == XFS_DIR3_FREE_MAGIC);
        } else {
                to->magic = be32_to_cpu(from->hdr.magic);
                to->firstdb = be32_to_cpu(from->hdr.firstdb);
                to->nvalid = be32_to_cpu(from->hdr.nvalid);
                to->nused = be32_to_cpu(from->hdr.nused);
                to->bests = from->bests;

                ASSERT(to->magic == XFS_DIR2_FREE_MAGIC);
        }
}

static void
xfs_dir2_free_hdr_to_disk(
        struct xfs_mount                *mp,
        struct xfs_dir2_free            *to,
        struct xfs_dir3_icfree_hdr      *from)
{
        if (xfs_sb_version_hascrc(&mp->m_sb)) {
                struct xfs_dir3_free    *to3 = (struct xfs_dir3_free *)to;

                ASSERT(from->magic == XFS_DIR3_FREE_MAGIC);

                to3->hdr.hdr.magic = cpu_to_be32(from->magic);
                to3->hdr.firstdb = cpu_to_be32(from->firstdb);
                to3->hdr.nvalid = cpu_to_be32(from->nvalid);
                to3->hdr.nused = cpu_to_be32(from->nused);
        } else {
                ASSERT(from->magic == XFS_DIR2_FREE_MAGIC);

                to->hdr.magic = cpu_to_be32(from->magic);
                to->hdr.firstdb = cpu_to_be32(from->firstdb);
                to->hdr.nvalid = cpu_to_be32(from->nvalid);
                to->hdr.nused = cpu_to_be32(from->nused);
        }
}

int
xfs_dir2_free_read(
        struct xfs_trans        *tp,
        struct xfs_inode        *dp,
        xfs_dablk_t             fbno,
        struct xfs_buf          **bpp)
{
        return __xfs_dir3_free_read(tp, dp, fbno, 0, bpp);
}

static int
xfs_dir2_free_try_read(
        struct xfs_trans        *tp,
        struct xfs_inode        *dp,
        xfs_dablk_t             fbno,
        struct xfs_buf          **bpp)
{
        return __xfs_dir3_free_read(tp, dp, fbno, XFS_DABUF_MAP_HOLE_OK, bpp);
}

static int
xfs_dir3_free_get_buf(
        xfs_da_args_t           *args,
        xfs_dir2_db_t           fbno,
        struct xfs_buf          **bpp)
{
        struct xfs_trans        *tp = args->trans;
        struct xfs_inode        *dp = args->dp;
        struct xfs_mount        *mp = dp->i_mount;
        struct xfs_buf          *bp;
        int                     error;
        struct xfs_dir3_icfree_hdr hdr;

        error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(args->geo, fbno),
                        &bp, XFS_DATA_FORK);
        if (error)
                return error;

        xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DIR_FREE_BUF);
        bp->b_ops = &xfs_dir3_free_buf_ops;

        /*
         * Initialize the new block to be empty, and remember
         * its first slot as our empty slot.
         */
        memset(bp->b_addr, 0, sizeof(struct xfs_dir3_free_hdr));
        memset(&hdr, 0, sizeof(hdr));

        if (xfs_sb_version_hascrc(&mp->m_sb)) {
                struct xfs_dir3_free_hdr *hdr3 = bp->b_addr;

                hdr.magic = XFS_DIR3_FREE_MAGIC;

                hdr3->hdr.blkno = cpu_to_be64(bp->b_bn);
                hdr3->hdr.owner = cpu_to_be64(dp->i_ino);
                uuid_copy(&hdr3->hdr.uuid, &mp->m_sb.sb_meta_uuid);
        } else
                hdr.magic = XFS_DIR2_FREE_MAGIC;
        xfs_dir2_free_hdr_to_disk(mp, bp->b_addr, &hdr);
        *bpp = bp;
        return 0;
}

/*
 * Log entries from a freespace block.
 */
STATIC void
xfs_dir2_free_log_bests(
        struct xfs_da_args      *args,
        struct xfs_dir3_icfree_hdr *hdr,
        struct xfs_buf          *bp,
        int                     first,          /* first entry to log */
        int                     last)           /* last entry to log */
{
        struct xfs_dir2_free    *free = bp->b_addr;

        ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC) ||
               free->hdr.magic == cpu_to_be32(XFS_DIR3_FREE_MAGIC));
        xfs_trans_log_buf(args->trans, bp,
                          (char *)&hdr->bests[first] - (char *)free,
                          (char *)&hdr->bests[last] - (char *)free +
                           sizeof(hdr->bests[0]) - 1);
}

/*
 * Log header from a freespace block.
 */
static void
xfs_dir2_free_log_header(
        struct xfs_da_args      *args,
        struct xfs_buf          *bp)
{
#ifdef DEBUG
        xfs_dir2_free_t         *free;          /* freespace structure */

        free = bp->b_addr;
        ASSERT(free->hdr.magic == cpu_to_be32(XFS_DIR2_FREE_MAGIC) ||
               free->hdr.magic == cpu_to_be32(XFS_DIR3_FREE_MAGIC));
#endif
        xfs_trans_log_buf(args->trans, bp, 0,
                          args->geo->free_hdr_size - 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 */
        __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 */
        int                     n;              /* count of live freespc ents */
        xfs_dir2_data_off_t     off;            /* freespace entry value */
        xfs_trans_t             *tp;            /* transaction pointer */
        struct xfs_dir3_icfree_hdr freehdr;

        trace_xfs_dir2_leaf_to_node(args);

        dp = args->dp;
        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_byte_to_db(args->geo, XFS_DIR2_FREE_OFFSET));
        /*
         * Get the buffer for the new freespace block.
         */
        error = xfs_dir3_free_get_buf(args, fdb, &fbp);
        if (error)
                return error;

        xfs_dir2_free_hdr_from_disk(dp->i_mount, &freehdr, fbp->b_addr);
        leaf = lbp->b_addr;
        ltp = xfs_dir2_leaf_tail_p(args->geo, leaf);
        if (be32_to_cpu(ltp->bestcount) >
                                (uint)dp->i_d.di_size / args->geo->blksize) {
                xfs_buf_mark_corrupt(lbp);
                return -EFSCORRUPTED;
        }

        /*
         * Copy freespace entries from the leaf block to the new block.
         * Count active entries.
         */
        from = xfs_dir2_leaf_bests_p(ltp);
        for (i = n = 0; i < be32_to_cpu(ltp->bestcount); i++, from++) {
                off = be16_to_cpu(*from);
                if (off != NULLDATAOFF)
                        n++;
                freehdr.bests[i] = cpu_to_be16(off);
        }

        /*
         * Now initialize the freespace block header.
         */
        freehdr.nused = n;
        freehdr.nvalid = be32_to_cpu(ltp->bestcount);

        xfs_dir2_free_hdr_to_disk(dp->i_mount, fbp->b_addr, &freehdr);
        xfs_dir2_free_log_bests(args, &freehdr, fbp, 0, freehdr.nvalid - 1);
        xfs_dir2_free_log_header(args, fbp);

        /*
         * Converting the leaf to a leafnode is just a matter of changing the
         * magic number and the ops. Do the change directly to the buffer as
         * it's less work (and less code) than decoding the header to host
         * format and back again.
         */
        if (leaf->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAF1_MAGIC))
                leaf->hdr.info.magic = cpu_to_be16(XFS_DIR2_LEAFN_MAGIC);
        else
                leaf->hdr.info.magic = cpu_to_be16(XFS_DIR3_LEAFN_MAGIC);
        lbp->b_ops = &xfs_dir3_leafn_buf_ops;
        xfs_trans_buf_set_type(tp, lbp, XFS_BLFT_DIR_LEAFN_BUF);
        xfs_dir3_leaf_log_header(args, lbp);
        xfs_dir3_leaf_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 */
        struct xfs_da_args      *args,          /* operation arguments */
        int                     index)          /* insertion pt for new entry */
{
        struct xfs_dir3_icleaf_hdr leafhdr;
        struct xfs_inode        *dp = args->dp;
        struct xfs_dir2_leaf    *leaf = bp->b_addr;
        struct xfs_dir2_leaf_entry *lep;
        struct xfs_dir2_leaf_entry *ents;
        int                     compact;        /* compacting stale leaves */
        int                     highstale = 0;  /* next stale entry */
        int                     lfloghigh;      /* high leaf entry logging */
        int                     lfloglow;       /* low leaf entry logging */
        int                     lowstale = 0;   /* previous stale entry */

        trace_xfs_dir2_leafn_add(args, index);

        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &leafhdr, leaf);
        ents = leafhdr.ents;

        /*
         * Quick check just to make sure we are not going to index
         * into other peoples memory
         */
        if (index < 0) {
                xfs_buf_mark_corrupt(bp);
                return -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 (leafhdr.count == args->geo->leaf_max_ents) {
                if (!leafhdr.stale)
                        return -ENOSPC;
                compact = leafhdr.stale > 1;
        } else
                compact = 0;
        ASSERT(index == 0 || be32_to_cpu(ents[index - 1].hashval) <= args->hashval);
        ASSERT(index == leafhdr.count ||
               be32_to_cpu(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_dir3_leaf_compact_x1(&leafhdr, ents, &index, &lowstale,
                                         &highstale, &lfloglow, &lfloghigh);
        else if (leafhdr.stale) {
                /*
                 * Set impossible logging indices for this case.
                 */
                lfloglow = leafhdr.count;
                lfloghigh = -1;
        }

        /*
         * Insert the new entry, log everything.
         */
        lep = xfs_dir3_leaf_find_entry(&leafhdr, ents, index, compact, lowstale,
                                       highstale, &lfloglow, &lfloghigh);

        lep->hashval = cpu_to_be32(args->hashval);
        lep->address = cpu_to_be32(xfs_dir2_db_off_to_dataptr(args->geo,
                                args->blkno, args->index));

        xfs_dir2_leaf_hdr_to_disk(dp->i_mount, leaf, &leafhdr);
        xfs_dir3_leaf_log_header(args, bp);
        xfs_dir3_leaf_log_ents(args, &leafhdr, bp, lfloglow, lfloghigh);
        xfs_dir3_leaf_check(dp, bp);
        return 0;
}

#ifdef DEBUG
static void
xfs_dir2_free_hdr_check(
        struct xfs_inode *dp,
        struct xfs_buf  *bp,
        xfs_dir2_db_t   db)
{
        struct xfs_dir3_icfree_hdr hdr;

        xfs_dir2_free_hdr_from_disk(dp->i_mount, &hdr, bp->b_addr);

        ASSERT((hdr.firstdb % dp->i_mount->m_dir_geo->free_max_bests) == 0);
        ASSERT(hdr.firstdb <= db);
        ASSERT(db < hdr.firstdb + hdr.nvalid);
}
#else
#define xfs_dir2_free_hdr_check(dp, bp, db)
#endif  /* DEBUG */

/*
 * Return the last hash value in the leaf.
 * Stale entries are ok.
 */
xfs_dahash_t                                    /* hash value */
xfs_dir2_leaf_lasthash(
        struct xfs_inode *dp,
        struct xfs_buf  *bp,                    /* leaf buffer */
        int             *count)                 /* count of entries in leaf */
{
        struct xfs_dir3_icleaf_hdr leafhdr;

        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &leafhdr, bp->b_addr);

        ASSERT(leafhdr.magic == XFS_DIR2_LEAFN_MAGIC ||
               leafhdr.magic == XFS_DIR3_LEAFN_MAGIC ||
               leafhdr.magic == XFS_DIR2_LEAF1_MAGIC ||
               leafhdr.magic == XFS_DIR3_LEAF1_MAGIC);

        if (count)
                *count = leafhdr.count;
        if (!leafhdr.count)
                return 0;
        return be32_to_cpu(leafhdr.ents[leafhdr.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 */
        struct xfs_dir3_icleaf_hdr leafhdr;

        dp = args->dp;
        tp = args->trans;
        mp = dp->i_mount;
        leaf = bp->b_addr;
        xfs_dir2_leaf_hdr_from_disk(mp, &leafhdr, leaf);

        xfs_dir3_leaf_check(dp, bp);
        ASSERT(leafhdr.count > 0);

        /*
         * 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) ||
                       free->hdr.magic == cpu_to_be32(XFS_DIR3_FREE_MAGIC));
        }
        length = xfs_dir2_data_entsize(mp, args->namelen);
        /*
         * Loop over leaf entries with the right hash value.
         */
        for (lep = &leafhdr.ents[index];
             index < leafhdr.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(args->geo,
                                               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) {
                        struct xfs_dir3_icfree_hdr freehdr;

                        curdb = newdb;
                        /*
                         * Convert the data block to the free block
                         * holding its freespace information.
                         */
                        newfdb = xfs_dir2_db_to_fdb(args->geo, 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);

                                error = xfs_dir2_free_read(tp, dp,
                                                xfs_dir2_db_to_da(args->geo,
                                                                  newfdb),
                                                &curbp);
                                if (error)
                                        return error;
                                free = curbp->b_addr;

                                xfs_dir2_free_hdr_check(dp, curbp, curdb);
                        }
                        /*
                         * Get the index for our entry.
                         */
                        fi = xfs_dir2_db_to_fdindex(args->geo, curdb);
                        /*
                         * If it has room, return it.
                         */
                        xfs_dir2_free_hdr_from_disk(mp, &freehdr, free);
                        if (XFS_IS_CORRUPT(mp,
                                           freehdr.bests[fi] ==
                                           cpu_to_be16(NULLDATAOFF))) {
                                if (curfdb != newfdb)
                                        xfs_trans_brelse(tp, curbp);
                                return -EFSCORRUPTED;
                        }
                        curfdb = newfdb;
                        if (be16_to_cpu(freehdr.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;

                /*
                 * Important: this magic number is not in the buffer - it's for
                 * buffer type information and therefore only the free/data type
                 * matters here, not whether CRCs are enabled or not.
                 */
                state->extrablk.magic = XFS_DIR2_FREE_MAGIC;
        } else {
                state->extravalid = 0;
        }
        /*
         * Return the index, that will be the insertion point.
         */
        *indexp = index;
        return -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 */
        struct xfs_dir3_icleaf_hdr leafhdr;

        dp = args->dp;
        tp = args->trans;
        mp = dp->i_mount;
        leaf = bp->b_addr;
        xfs_dir2_leaf_hdr_from_disk(mp, &leafhdr, leaf);

        xfs_dir3_leaf_check(dp, bp);
        if (leafhdr.count <= 0) {
                xfs_buf_mark_corrupt(bp);
                return -EFSCORRUPTED;
        }

        /*
         * 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 = &leafhdr.ents[index];
             index < leafhdr.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(args->geo,
                                               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_dir3_data_read(tp, dp,
                                                xfs_dir2_db_to_da(args->geo,
                                                                  newdb),
                                                0, &curbp);
                                if (error)
                                        return error;
                        }
                        xfs_dir3_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(args->geo,
                                                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 = xfs_dir2_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);
                        args->filetype = xfs_dir2_data_get_ftype(mp, dep);
                        *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;
                        curbp->b_ops = &xfs_dir3_data_buf_ops;
                        xfs_trans_buf_set_type(tp, curbp, XFS_BLFT_DIR_DATA_BUF);
                        if (cmp == XFS_CMP_EXACT)
                                return -EEXIST;
                }
        }
        ASSERT(index == leafhdr.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;
                        curbp->b_ops = &xfs_dir3_data_buf_ops;
                        xfs_trans_buf_set_type(tp, curbp, XFS_BLFT_DIR_DATA_BUF);
                } 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 -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_dir3_leafn_moveents(
        xfs_da_args_t                   *args,  /* operation arguments */
        struct xfs_buf                  *bp_s,  /* source */
        struct xfs_dir3_icleaf_hdr      *shdr,
        struct xfs_dir2_leaf_entry      *sents,
        int                             start_s,/* source leaf index */
        struct xfs_buf                  *bp_d,  /* destination */
        struct xfs_dir3_icleaf_hdr      *dhdr,
        struct xfs_dir2_leaf_entry      *dents,
        int                             start_d,/* destination leaf index */
        int                             count)  /* count of leaves to copy */
{
        int                             stale;  /* count stale leaves copied */

        trace_xfs_dir2_leafn_moveents(args, start_s, start_d, count);

        /*
         * Silently return if nothing to do.
         */
        if (count == 0)
                return;

        /*
         * 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 < dhdr->count) {
                memmove(&dents[start_d + count], &dents[start_d],
                        (dhdr->count - start_d) * sizeof(xfs_dir2_leaf_entry_t));
                xfs_dir3_leaf_log_ents(args, dhdr, bp_d, start_d + count,
                                       count + dhdr->count - 1);
        }
        /*
         * If the source has stale leaves, count the ones in the copy range
         * so we can update the header correctly.
         */
        if (shdr->stale) {
                int     i;                      /* temp leaf index */

                for (i = start_s, stale = 0; i < start_s + count; i++) {
                        if (sents[i].address ==
                                        cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
                                stale++;
                }
        } else
                stale = 0;
        /*
         * Copy the leaf entries from source to destination.
         */
        memcpy(&dents[start_d], &sents[start_s],
                count * sizeof(xfs_dir2_leaf_entry_t));
        xfs_dir3_leaf_log_ents(args, dhdr, 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 < shdr->count) {
                memmove(&sents[start_s], &sents[start_s + count],
                        count * sizeof(xfs_dir2_leaf_entry_t));
                xfs_dir3_leaf_log_ents(args, shdr, bp_s, start_s,
                                       start_s + count - 1);
        }

        /*
         * Update the headers and log them.
         */
        shdr->count -= count;
        shdr->stale -= stale;
        dhdr->count += count;
        dhdr->stale += stale;
}

/*
 * 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_inode        *dp,
        struct xfs_buf          *leaf1_bp,              /* leaf1 buffer */
        struct xfs_buf          *leaf2_bp)              /* leaf2 buffer */
{
        struct xfs_dir2_leaf    *leaf1 = leaf1_bp->b_addr;
        struct xfs_dir2_leaf    *leaf2 = leaf2_bp->b_addr;
        struct xfs_dir2_leaf_entry *ents1;
        struct xfs_dir2_leaf_entry *ents2;
        struct xfs_dir3_icleaf_hdr hdr1;
        struct xfs_dir3_icleaf_hdr hdr2;

        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &hdr1, leaf1);
        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &hdr2, leaf2);
        ents1 = hdr1.ents;
        ents2 = hdr2.ents;

        if (hdr1.count > 0 && hdr2.count > 0 &&
            (be32_to_cpu(ents2[0].hashval) < be32_to_cpu(ents1[0].hashval) ||
             be32_to_cpu(ents2[hdr2.count - 1].hashval) <
                                be32_to_cpu(ents1[hdr1.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 */
#if defined(DEBUG) || defined(XFS_WARN)
        int                     oldstale;       /* old count of stale leaves */
#endif
        int                     oldsum;         /* old total leaf count */
        int                     swap_blocks;    /* swapped leaf blocks */
        struct xfs_dir2_leaf_entry *ents1;
        struct xfs_dir2_leaf_entry *ents2;
        struct xfs_dir3_icleaf_hdr hdr1;
        struct xfs_dir3_icleaf_hdr hdr2;
        struct xfs_inode        *dp = state->args->dp;

        args = state->args;
        /*
         * If the block order is wrong, swap the arguments.
         */
        swap_blocks = xfs_dir2_leafn_order(dp, blk1->bp, blk2->bp);
        if (swap_blocks)
                swap(blk1, blk2);

        leaf1 = blk1->bp->b_addr;
        leaf2 = blk2->bp->b_addr;
        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &hdr1, leaf1);
        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &hdr2, leaf2);
        ents1 = hdr1.ents;
        ents2 = hdr2.ents;

        oldsum = hdr1.count + hdr2.count;
#if defined(DEBUG) || defined(XFS_WARN)
        oldstale = hdr1.stale + hdr2.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 >= hdr1.count)
                        midhash = be32_to_cpu(ents2[mid - hdr1.count].hashval);
                else
                        midhash = be32_to_cpu(ents1[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 = hdr1.count - mid + (isleft == 0);
        if (count > 0)
                xfs_dir3_leafn_moveents(args, blk1->bp, &hdr1, ents1,
                                        hdr1.count - count, blk2->bp,
                                        &hdr2, ents2, 0, count);
        else if (count < 0)
                xfs_dir3_leafn_moveents(args, blk2->bp, &hdr2, ents2, 0,
                                        blk1->bp, &hdr1, ents1,
                                        hdr1.count, count);

        ASSERT(hdr1.count + hdr2.count == oldsum);
        ASSERT(hdr1.stale + hdr2.stale == oldstale);

        /* log the changes made when moving the entries */
        xfs_dir2_leaf_hdr_to_disk(dp->i_mount, leaf1, &hdr1);
        xfs_dir2_leaf_hdr_to_disk(dp->i_mount, leaf2, &hdr2);
        xfs_dir3_leaf_log_header(args, blk1->bp);
        xfs_dir3_leaf_log_header(args, blk2->bp);

        xfs_dir3_leaf_check(dp, blk1->bp);
        xfs_dir3_leaf_check(dp, blk2->bp);

        /*
         * Mark whether we're inserting into the old or new leaf.
         */
        if (hdr1.count < hdr2.count)
                state->inleaf = swap_blocks;
        else if (hdr1.count > hdr2.count)
                state->inleaf = !swap_blocks;
        else
                state->inleaf = swap_blocks ^ (blk1->index <= hdr1.count);
        /*
         * Adjust the expected index for insertion.
         */
        if (!state->inleaf)
                blk2->index = blk1->index - hdr1.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(dp->i_mount,
        "%s: picked the wrong leaf? reverting original leaf: blk1->index %d",
                        __func__, blk1->index);
        }
}

static int
xfs_dir3_data_block_free(
        xfs_da_args_t           *args,
        struct xfs_dir2_data_hdr *hdr,
        struct xfs_dir2_free    *free,
        xfs_dir2_db_t           fdb,
        int                     findex,
        struct xfs_buf          *fbp,
        int                     longest)
{
        int                     logfree = 0;
        struct xfs_dir3_icfree_hdr freehdr;
        struct xfs_inode        *dp = args->dp;

        xfs_dir2_free_hdr_from_disk(dp->i_mount, &freehdr, free);
        if (hdr) {
                /*
                 * Data block is not empty, just set the free entry to the new
                 * value.
                 */
                freehdr.bests[findex] = cpu_to_be16(longest);
                xfs_dir2_free_log_bests(args, &freehdr, fbp, findex, findex);
                return 0;
        }

        /* One less used entry in the free table. */
        freehdr.nused--;

        /*
         * 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 == freehdr.nvalid - 1) {
                int     i;              /* free entry index */

                for (i = findex - 1; i >= 0; i--) {
                        if (freehdr.bests[i] != cpu_to_be16(NULLDATAOFF))
                                break;
                }
                freehdr.nvalid = i + 1;
                logfree = 0;
        } else {
                /* Not the last entry, just punch it out.  */
                freehdr.bests[findex] = cpu_to_be16(NULLDATAOFF);
                logfree = 1;
        }

        xfs_dir2_free_hdr_to_disk(dp->i_mount, free, &freehdr);
        xfs_dir2_free_log_header(args, fbp);

        /*
         * If there are no useful entries left in the block, get rid of the
         * block if we can.
         */
        if (!freehdr.nused) {
                int error;

                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.
                 */
        }

        /* Log the free entry that changed, unless we got rid of it.  */
        if (logfree)
                xfs_dir2_free_log_bests(args, &freehdr, fbp, findex, findex);
        return 0;
}

/*
 * 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 */
{
        struct xfs_da_geometry  *geo = args->geo;
        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 */
        int                     needlog;        /* need to log data header */
        int                     needscan;       /* need to rescan data frees */
        xfs_trans_t             *tp;            /* transaction pointer */
        struct xfs_dir2_data_free *bf;          /* bestfree table */
        struct xfs_dir3_icleaf_hdr leafhdr;

        trace_xfs_dir2_leafn_remove(args, index);

        dp = args->dp;
        tp = args->trans;
        leaf = bp->b_addr;
        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &leafhdr, leaf);

        /*
         * Point to the entry we're removing.
         */
        lep = &leafhdr.ents[index];

        /*
         * Extract the data block and offset from the entry.
         */
        db = xfs_dir2_dataptr_to_db(geo, be32_to_cpu(lep->address));
        ASSERT(dblk->blkno == db);
        off = xfs_dir2_dataptr_to_off(geo, be32_to_cpu(lep->address));
        ASSERT(dblk->index == off);

        /*
         * Kill the leaf entry by marking it stale.
         * Log the leaf block changes.
         */
        leafhdr.stale++;
        xfs_dir2_leaf_hdr_to_disk(dp->i_mount, leaf, &leafhdr);
        xfs_dir3_leaf_log_header(args, bp);

        lep->address = cpu_to_be32(XFS_DIR2_NULL_DATAPTR);
        xfs_dir3_leaf_log_ents(args, &leafhdr, 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);
        bf = xfs_dir2_data_bestfree_p(dp->i_mount, hdr);
        longest = be16_to_cpu(bf[0].length);
        needlog = needscan = 0;
        xfs_dir2_data_make_free(args, dbp, off,
                xfs_dir2_data_entsize(dp->i_mount, dep->namelen), &needlog,
                &needscan);
        /*
         * Rescan the data block freespaces for bestfree.
         * Log the data block header if needed.
         */
        if (needscan)
                xfs_dir2_data_freescan(dp->i_mount, hdr, &needlog);
        if (needlog)
                xfs_dir2_data_log_header(args, dbp);
        xfs_dir3_data_check(dp, dbp);
        /*
         * If the longest data block freespace changes, need to update
         * the corresponding freeblock entry.
         */
        if (longest < be16_to_cpu(bf[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 */

                /*
                 * Convert the data block number to a free block,
                 * read in the free block.
                 */
                fdb = xfs_dir2_db_to_fdb(geo, db);
                error = xfs_dir2_free_read(tp, dp, xfs_dir2_db_to_da(geo, fdb),
                                           &fbp);
                if (error)
                        return error;
                free = fbp->b_addr;
#ifdef DEBUG
        {
                struct xfs_dir3_icfree_hdr freehdr;

                xfs_dir2_free_hdr_from_disk(dp->i_mount, &freehdr, free);
                ASSERT(freehdr.firstdb == geo->free_max_bests *
                        (fdb - xfs_dir2_byte_to_db(geo, XFS_DIR2_FREE_OFFSET)));
        }
#endif
                /*
                 * Calculate which entry we need to fix.
                 */
                findex = xfs_dir2_db_to_fdindex(geo, db);
                longest = be16_to_cpu(bf[0].length);
                /*
                 * If the data block is now empty we can get rid of it
                 * (usually).
                 */
                if (longest == geo->blksize - geo->data_entry_offset) {
                        /*
                         * 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.
                 */
                error = xfs_dir3_data_block_free(args, hdr, free,
                                                 fdb, findex, fbp, longest);
                if (error)
                        return error;
        }

        xfs_dir3_leaf_check(dp, bp);
        /*
         * Return indication of whether this leaf block is empty enough
         * to justify trying to join it with a neighbor.
         */
        *rval = (geo->leaf_hdr_size +
                 (uint)sizeof(leafhdr.ents) * (leafhdr.count - leafhdr.stale)) <
                geo->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 */
        struct xfs_inode        *dp;

        /*
         * Allocate space for a new leaf node.
         */
        args = state->args;
        dp = args->dp;
        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_dir3_leaf_get_buf(args, xfs_dir2_da_to_db(args->geo, 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_da3_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_leaf_lasthash(dp, oldblk->bp, NULL);
        newblk->hashval = xfs_dir2_leaf_lasthash(dp, newblk->bp, NULL);
        xfs_dir3_leaf_check(dp, oldblk->bp);
        xfs_dir3_leaf_check(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_dir2_leaf_t         *leaf;          /* leaf structure */
        int                     rval;           /* result from path_shift */
        struct xfs_dir3_icleaf_hdr leafhdr;
        struct xfs_dir2_leaf_entry *ents;
        struct xfs_inode        *dp = state->args->dp;

        /*
         * 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];
        leaf = blk->bp->b_addr;
        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &leafhdr, leaf);
        ents = leafhdr.ents;
        xfs_dir3_leaf_check(dp, blk->bp);

        count = leafhdr.count - leafhdr.stale;
        bytes = state->args->geo->leaf_hdr_size + count * sizeof(ents[0]);
        if (bytes > (state->args->geo->blksize >> 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 = (leafhdr.forw != 0);
                memcpy(&state->altpath, &state->path, sizeof(state->path));
                error = xfs_da3_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 = leafhdr.forw < leafhdr.back;
        for (i = 0, bp = NULL; i < 2; forward = !forward, i++) {
                struct xfs_dir3_icleaf_hdr hdr2;

                blkno = forward ? leafhdr.forw : leafhdr.back;
                if (blkno == 0)
                        continue;
                /*
                 * Read the sibling leaf block.
                 */
                error = xfs_dir3_leafn_read(state->args->trans, dp, blkno, &bp);
                if (error)
                        return error;

                /*
                 * Count bytes in the two blocks combined.
                 */
                count = leafhdr.count - leafhdr.stale;
                bytes = state->args->geo->blksize -
                        (state->args->geo->blksize >> 2);

                leaf = bp->b_addr;
                xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &hdr2, leaf);
                ents = hdr2.ents;
                count += hdr2.count - hdr2.stale;
                bytes -= count * sizeof(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_da3_path_shift(state, &state->altpath, forward, 0,
                        &rval);
        else
                error = xfs_da3_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 */
        struct xfs_dir3_icleaf_hdr savehdr;
        struct xfs_dir3_icleaf_hdr drophdr;
        struct xfs_dir2_leaf_entry *sents;
        struct xfs_dir2_leaf_entry *dents;
        struct xfs_inode        *dp = state->args->dp;

        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;

        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &savehdr, save_leaf);
        xfs_dir2_leaf_hdr_from_disk(dp->i_mount, &drophdr, drop_leaf);
        sents = savehdr.ents;
        dents = drophdr.ents;

        /*
         * If there are any stale leaf entries, take this opportunity
         * to purge them.
         */
        if (drophdr.stale)
                xfs_dir3_leaf_compact(args, &drophdr, drop_blk->bp);
        if (savehdr.stale)
                xfs_dir3_leaf_compact(args, &savehdr, save_blk->bp);

        /*
         * Move the entries from drop to the appropriate end of save.
         */
        drop_blk->hashval = be32_to_cpu(dents[drophdr.count - 1].hashval);
        if (xfs_dir2_leafn_order(dp, save_blk->bp, drop_blk->bp))
                xfs_dir3_leafn_moveents(args, drop_blk->bp, &drophdr, dents, 0,
                                        save_blk->bp, &savehdr, sents, 0,
                                        drophdr.count);
        else
                xfs_dir3_leafn_moveents(args, drop_blk->bp, &drophdr, dents, 0,
                                        save_blk->bp, &savehdr, sents,
                                        savehdr.count, drophdr.count);
        save_blk->hashval = be32_to_cpu(sents[savehdr.count - 1].hashval);

        /* log the changes made when moving the entries */
        xfs_dir2_leaf_hdr_to_disk(dp->i_mount, save_leaf, &savehdr);
        xfs_dir2_leaf_hdr_to_disk(dp->i_mount, drop_leaf, &drophdr);
        xfs_dir3_leaf_log_header(args, save_blk->bp);
        xfs_dir3_leaf_log_header(args, drop_blk->bp);

        xfs_dir3_leaf_check(dp, save_blk->bp);
        xfs_dir3_leaf_check(dp, drop_blk->bp);
}

/*
 * Add a new data block to the directory at the free space index that the caller
 * has specified.
 */
static int
xfs_dir2_node_add_datablk(
        struct xfs_da_args      *args,
        struct xfs_da_state_blk *fblk,
        xfs_dir2_db_t           *dbno,
        struct xfs_buf          **dbpp,
        struct xfs_buf          **fbpp,
        struct xfs_dir3_icfree_hdr *hdr,
        int                     *findex)
{
        struct xfs_inode        *dp = args->dp;
        struct xfs_trans        *tp = args->trans;
        struct xfs_mount        *mp = dp->i_mount;
        struct xfs_dir2_data_free *bf;
        xfs_dir2_db_t           fbno;
        struct xfs_buf          *fbp;
        struct xfs_buf          *dbp;
        int                     error;

        /* Not allowed to allocate, return failure. */
        if (args->total == 0)
                return -ENOSPC;

        /* Allocate and initialize the new data block.  */
        error = xfs_dir2_grow_inode(args, XFS_DIR2_DATA_SPACE, dbno);
        if (error)
                return error;
        error = xfs_dir3_data_init(args, *dbno, &dbp);
        if (error)
                return error;

        /*
         * Get the freespace block corresponding to the data block
         * that was just allocated.
         */
        fbno = xfs_dir2_db_to_fdb(args->geo, *dbno);
        error = xfs_dir2_free_try_read(tp, dp,
                               xfs_dir2_db_to_da(args->geo, fbno), &fbp);
        if (error)
                return error;

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

                if (XFS_IS_CORRUPT(mp,
                                   xfs_dir2_db_to_fdb(args->geo, *dbno) !=
                                   fbno)) {
                        xfs_alert(mp,
"%s: dir ino %llu needed freesp block %lld for data block %lld, got %lld",
                                __func__, (unsigned long long)dp->i_ino,
                                (long long)xfs_dir2_db_to_fdb(args->geo, *dbno),
                                (long long)*dbno, (long long)fbno);
                        if (fblk) {
                                xfs_alert(mp,
                        " fblk "PTR_FMT" blkno %llu index %d magic 0x%x",
                                        fblk, (unsigned long long)fblk->blkno,
                                        fblk->index, fblk->magic);
                        } else {
                                xfs_alert(mp, " ... fblk is NULL");
                        }
                        return -EFSCORRUPTED;
                }

                /* Get a buffer for the new block. */
                error = xfs_dir3_free_get_buf(args, fbno, &fbp);
                if (error)
                        return error;
                xfs_dir2_free_hdr_from_disk(mp, hdr, fbp->b_addr);

                /* Remember the first slot as our empty slot. */
                hdr->firstdb = (fbno - xfs_dir2_byte_to_db(args->geo,
                                                        XFS_DIR2_FREE_OFFSET)) *
                                args->geo->free_max_bests;
        } else {
                xfs_dir2_free_hdr_from_disk(mp, hdr, fbp->b_addr);
        }

        /* Set the freespace block index from the data block number. */
        *findex = xfs_dir2_db_to_fdindex(args->geo, *dbno);

        /* Extend the freespace table if the new data block is off the end. */
        if (*findex >= hdr->nvalid) {
                ASSERT(*findex < args->geo->free_max_bests);
                hdr->nvalid = *findex + 1;
                hdr->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 (hdr->bests[*findex] == cpu_to_be16(NULLDATAOFF)) {
                hdr->nused++;
                xfs_dir2_free_hdr_to_disk(mp, fbp->b_addr, hdr);
                xfs_dir2_free_log_header(args, fbp);
        }

        /* Update the freespace value for the new block in the table. */
        bf = xfs_dir2_data_bestfree_p(mp, dbp->b_addr);
        hdr->bests[*findex] = bf[0].length;

        *dbpp = dbp;
        *fbpp = fbp;
        return 0;
}

static int
xfs_dir2_node_find_freeblk(
        struct xfs_da_args      *args,
        struct xfs_da_state_blk *fblk,
        xfs_dir2_db_t           *dbnop,
        struct xfs_buf          **fbpp,
        struct xfs_dir3_icfree_hdr *hdr,
        int                     *findexp,
        int                     length)
{
        struct xfs_inode        *dp = args->dp;
        struct xfs_trans        *tp = args->trans;
        struct xfs_buf          *fbp = NULL;
        xfs_dir2_db_t           firstfbno;
        xfs_dir2_db_t           lastfbno;
        xfs_dir2_db_t           ifbno = -1;
        xfs_dir2_db_t           dbno = -1;
        xfs_dir2_db_t           fbno;
        xfs_fileoff_t           fo;
        int                     findex = 0;
        int                     error;

        /*
         * 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;
                findex = fblk->index;
                xfs_dir2_free_hdr_from_disk(dp->i_mount, hdr, fbp->b_addr);
                if (findex >= 0) {
                        /* caller already found the freespace for us. */
                        ASSERT(findex < hdr->nvalid);
                        ASSERT(be16_to_cpu(hdr->bests[findex]) != NULLDATAOFF);
                        ASSERT(be16_to_cpu(hdr->bests[findex]) >= length);
                        dbno = hdr->firstdb + findex;
                        goto found_block;
                }

                /*
                 * The data block looked at didn't have enough room.
                 * We'll start at the beginning of the freespace entries.
                 */
                ifbno = fblk->blkno;
                xfs_trans_brelse(tp, fbp);
                fbp = NULL;
                fblk->bp = NULL;
        }

        /*
         * If we don't have a data block yet, we're going to scan the freespace
         * data for a data block with enough free space in it.
         */
        error = xfs_bmap_last_offset(dp, &fo, XFS_DATA_FORK);
        if (error)
                return error;
        lastfbno = xfs_dir2_da_to_db(args->geo, (xfs_dablk_t)fo);
        firstfbno = xfs_dir2_byte_to_db(args->geo, XFS_DIR2_FREE_OFFSET);

        for (fbno = lastfbno - 1; fbno >= firstfbno; fbno--) {
                /* If it's ifbno we already looked at it. */
                if (fbno == ifbno)
                        continue;

                /*
                 * 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.
                 */
                error = xfs_dir2_free_try_read(tp, dp,
                                xfs_dir2_db_to_da(args->geo, fbno),
                                &fbp);
                if (error)
                        return error;
                if (!fbp)
                        continue;

                xfs_dir2_free_hdr_from_disk(dp->i_mount, hdr, fbp->b_addr);

                /* Scan the free entry array for a large enough free space. */
                for (findex = hdr->nvalid - 1; findex >= 0; findex--) {
                        if (be16_to_cpu(hdr->bests[findex]) != NULLDATAOFF &&
                            be16_to_cpu(hdr->bests[findex]) >= length) {
                                dbno = hdr->firstdb + findex;
                                goto found_block;
                        }
                }

                /* Didn't find free space, go on to next free block */
                xfs_trans_brelse(tp, fbp);
        }

found_block:
        *dbnop = dbno;
        *fbpp = fbp;
        *findexp = findex;
        return 0;
}

/*
 * 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
xfs_dir2_node_addname_int(
        struct xfs_da_args      *args,          /* operation arguments */
        struct xfs_da_state_blk *fblk)          /* optional freespace block */
{
        struct xfs_dir2_data_unused *dup;       /* data unused entry pointer */
        struct xfs_dir2_data_entry *dep;        /* data entry pointer */
        struct xfs_dir2_data_hdr *hdr;          /* data block header */
        struct xfs_dir2_data_free *bf;
        struct xfs_trans        *tp = args->trans;
        struct xfs_inode        *dp = args->dp;
        struct xfs_dir3_icfree_hdr freehdr;
        struct xfs_buf          *dbp;           /* data block buffer */
        struct xfs_buf          *fbp;           /* freespace buffer */
        xfs_dir2_data_aoff_t    aoff;
        xfs_dir2_db_t           dbno;           /* data block number */
        int                     error;          /* error return value */
        int                     findex;         /* freespace entry index */
        int                     length;         /* length of the new entry */
        int                     logfree = 0;    /* need to log free entry */
        int                     needlog = 0;    /* need to log data header */
        int                     needscan = 0;   /* need to rescan data frees */
        __be16                  *tagp;          /* data entry tag pointer */

        length = xfs_dir2_data_entsize(dp->i_mount, args->namelen);
        error = xfs_dir2_node_find_freeblk(args, fblk, &dbno, &fbp, &freehdr,
                                           &findex, length);
        if (error)
                return error;

        /*
         * Now we know if we must allocate blocks, so if we are checking whether
         * we can insert without allocation then we can return now.
         */
        if (args->op_flags & XFS_DA_OP_JUSTCHECK) {
                if (dbno == -1)
                        return -ENOSPC;
                return 0;
        }

        /*
         * If we don't have a data block, we need to allocate one and make
         * the freespace entries refer to it.
         */
        if (dbno == -1) {
                /* we're going to have to log the free block index later */
                logfree = 1;
                error = xfs_dir2_node_add_datablk(args, fblk, &dbno, &dbp, &fbp,
                                                  &freehdr, &findex);
        } else {
                /* Read the data block in. */
                error = xfs_dir3_data_read(tp, dp,
                                           xfs_dir2_db_to_da(args->geo, dbno),
                                           0, &dbp);
        }
        if (error)
                return error;

        /* setup for data block up now */
        hdr = dbp->b_addr;
        bf = xfs_dir2_data_bestfree_p(dp->i_mount, hdr);
        ASSERT(be16_to_cpu(bf[0].length) >= length);

        /* Point to the existing unused space. */
        dup = (xfs_dir2_data_unused_t *)
              ((char *)hdr + be16_to_cpu(bf[0].offset));

        /* Mark the first part of the unused space, inuse for us. */
        aoff = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
        error = xfs_dir2_data_use_free(args, dbp, dup, aoff, length,
                        &needlog, &needscan);
        if (error) {
                xfs_trans_brelse(tp, dbp);
                return error;
        }

        /* 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);
        xfs_dir2_data_put_ftype(dp->i_mount, dep, args->filetype);
        tagp = xfs_dir2_data_entry_tag_p(dp->i_mount, dep);
        *tagp = cpu_to_be16((char *)dep - (char *)hdr);
        xfs_dir2_data_log_entry(args, dbp, dep);

        /* Rescan the freespace and log the data block if needed. */
        if (needscan)
                xfs_dir2_data_freescan(dp->i_mount, hdr, &needlog);
        if (needlog)
                xfs_dir2_data_log_header(args, dbp);

        /* If the freespace block entry is now wrong, update it. */
        if (freehdr.bests[findex] != bf[0].length) {
                freehdr.bests[findex] = bf[0].length;
                logfree = 1;
        }

        /* Log the freespace entry if needed. */
        if (logfree)
                xfs_dir2_free_log_bests(args, &freehdr, fbp, findex, findex);

        /* Return the data block and offset in args. */
        args->blkno = (xfs_dablk_t)dbno;
        args->index = be16_to_cpu(*tagp);
        return 0;
}

/*
 * 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(args);
        /*
         * Look up the name.  We're not supposed to find it, but
         * this gives us the insertion point.
         */
        error = xfs_da3_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_da3_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_da3_split(state);
        }
done:
        xfs_da_state_free(state);
        return rval;
}

/*
 * Lookup an entry in a node-format directory.
 * All the real work happens in xfs_da3_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(args);

        /*
         * Fill in the path to the entry in the cursor.
         */
        error = xfs_da3_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(
        struct xfs_da_args      *args)          /* operation arguments */
{
        struct xfs_da_state_blk *blk;           /* leaf block */
        int                     error;          /* error return value */
        int                     rval;           /* operation return value */
        struct xfs_da_state     *state;         /* btree cursor */

        trace_xfs_dir2_node_removename(args);

        /*
         * Allocate and initialize the btree cursor.
         */
        state = xfs_da_state_alloc(args);

        /* Look up the entry we're deleting, set up the cursor. */
        error = xfs_da3_node_lookup_int(state, &rval);
        if (error)
                goto out_free;

        /* Didn't find it, upper layer screwed up. */
        if (rval != -EEXIST) {
                error = rval;
                goto out_free;
        }

        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)
                goto out_free;
        /*
         * Fix the hash values up the btree.
         */
        xfs_da3_fixhashpath(state, &state->path);
        /*
         * If we need to join leaf blocks, do it.
         */
        if (rval && state->path.active > 1)
                error = xfs_da3_join(state);
        /*
         * If no errors so far, try conversion to leaf format.
         */
        if (!error)
                error = xfs_dir2_node_to_leaf(state);
out_free:
        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 */
        int                     ftype;          /* new file type */
        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(args);

        /*
         * We have to save new inode number and ftype since
         * xfs_da3_node_lookup_int() is going to overwrite them
         */
        inum = args->inumber;
        ftype = args->filetype;

        /*
         * Lookup the entry to change in the btree.
         */
        error = xfs_da3_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) {
                struct xfs_dir3_icleaf_hdr      leafhdr;

                /*
                 * Find the leaf entry.
                 */
                blk = &state->path.blk[state->path.active - 1];
                ASSERT(blk->magic == XFS_DIR2_LEAFN_MAGIC);
                ASSERT(state->extravalid);

                xfs_dir2_leaf_hdr_from_disk(state->mp, &leafhdr,
                                            blk->bp->b_addr);
                /*
                 * Point to the data entry.
                 */
                hdr = state->extrablk.bp->b_addr;
                ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
                       hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC));
                dep = (xfs_dir2_data_entry_t *)
                      ((char *)hdr +
                       xfs_dir2_dataptr_to_off(args->geo,
                                be32_to_cpu(leafhdr.ents[blk->index].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_put_ftype(state->mp, dep, ftype);
                xfs_dir2_data_log_entry(args, 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_trans_t             *tp;            /* transaction pointer */
        struct xfs_dir3_icfree_hdr freehdr;

        dp = args->dp;
        tp = args->trans;

        *rvalp = 0;

        /*
         * Read the freespace block.
         */
        error = xfs_dir2_free_try_read(tp, dp, fo, &bp);
        if (error)
                return error;
        /*
         * There can be holes in freespace.  If fo is a hole, there's
         * nothing to do.
         */
        if (!bp)
                return 0;
        free = bp->b_addr;
        xfs_dir2_free_hdr_from_disk(dp->i_mount, &freehdr, free);

        /*
         * If there are used entries, there's nothing to do.
         */
        if (freehdr.nused > 0) {
                xfs_trans_brelse(tp, bp);
                return 0;
        }
        /*
         * Blow the block away.
         */
        error = xfs_dir2_shrink_inode(args,
                        xfs_dir2_da_to_db(args->geo, (xfs_dablk_t)fo), bp);
        if (error) {
                /*
                 * 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;
}