/*
 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_mount.h"
#include "xfs_itable.h"
#include "xfs_inode_item.h"
#include "xfs_extfree_item.h"
#include "xfs_alloc.h"
#include "xfs_bmap.h"
#include "xfs_rtalloc.h"
#include "xfs_error.h"
#include "xfs_attr_leaf.h"
#include "xfs_quota.h"
#include "xfs_trans_space.h"
#include "xfs_buf_item.h"
#include "xfs_filestream.h"
#include "xfs_vnodeops.h"
#include "xfs_trace.h"
#include "xfs_symlink.h"


kmem_zone_t             *xfs_bmap_free_item_zone;

/*
 * Miscellaneous helper functions
 */

/*
 * Compute and fill in the value of the maximum depth of a bmap btree
 * in this filesystem.  Done once, during mount.
 */
void
xfs_bmap_compute_maxlevels(
        xfs_mount_t     *mp,            /* file system mount structure */
        int             whichfork)      /* data or attr fork */
{
        int             level;          /* btree level */
        uint            maxblocks;      /* max blocks at this level */
        uint            maxleafents;    /* max leaf entries possible */
        int             maxrootrecs;    /* max records in root block */
        int             minleafrecs;    /* min records in leaf block */
        int             minnoderecs;    /* min records in node block */
        int             sz;             /* root block size */

        /*
         * The maximum number of extents in a file, hence the maximum
         * number of leaf entries, is controlled by the type of di_nextents
         * (a signed 32-bit number, xfs_extnum_t), or by di_anextents
         * (a signed 16-bit number, xfs_aextnum_t).
         *
         * Note that we can no longer assume that if we are in ATTR1 that
         * the fork offset of all the inodes will be
         * (xfs_default_attroffset(ip) >> 3) because we could have mounted
         * with ATTR2 and then mounted back with ATTR1, keeping the
         * di_forkoff's fixed but probably at various positions. Therefore,
         * for both ATTR1 and ATTR2 we have to assume the worst case scenario
         * of a minimum size available.
         */
        if (whichfork == XFS_DATA_FORK) {
                maxleafents = MAXEXTNUM;
                sz = XFS_BMDR_SPACE_CALC(MINDBTPTRS);
        } else {
                maxleafents = MAXAEXTNUM;
                sz = XFS_BMDR_SPACE_CALC(MINABTPTRS);
        }
        maxrootrecs = xfs_bmdr_maxrecs(mp, sz, 0);
        minleafrecs = mp->m_bmap_dmnr[0];
        minnoderecs = mp->m_bmap_dmnr[1];
        maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs;
        for (level = 1; maxblocks > 1; level++) {
                if (maxblocks <= maxrootrecs)
                        maxblocks = 1;
                else
                        maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs;
        }
        mp->m_bm_maxlevels[whichfork] = level;
}

/*
 * Convert the given file system block to a disk block.  We have to treat it
 * differently based on whether the file is a real time file or not, because the
 * bmap code does.
 */
xfs_daddr_t
xfs_fsb_to_db(struct xfs_inode *ip, xfs_fsblock_t fsb)
{
        return (XFS_IS_REALTIME_INODE(ip) ? \
                 (xfs_daddr_t)XFS_FSB_TO_BB((ip)->i_mount, (fsb)) : \
                 XFS_FSB_TO_DADDR((ip)->i_mount, (fsb)));
}

STATIC int                              /* error */
xfs_bmbt_lookup_eq(
        struct xfs_btree_cur    *cur,
        xfs_fileoff_t           off,
        xfs_fsblock_t           bno,
        xfs_filblks_t           len,
        int                     *stat)  /* success/failure */
{
        cur->bc_rec.b.br_startoff = off;
        cur->bc_rec.b.br_startblock = bno;
        cur->bc_rec.b.br_blockcount = len;
        return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
}

STATIC int                              /* error */
xfs_bmbt_lookup_ge(
        struct xfs_btree_cur    *cur,
        xfs_fileoff_t           off,
        xfs_fsblock_t           bno,
        xfs_filblks_t           len,
        int                     *stat)  /* success/failure */
{
        cur->bc_rec.b.br_startoff = off;
        cur->bc_rec.b.br_startblock = bno;
        cur->bc_rec.b.br_blockcount = len;
        return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
}

/*
 * Check if the inode needs to be converted to btree format.
 */
static inline bool xfs_bmap_needs_btree(struct xfs_inode *ip, int whichfork)
{
        return XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
                XFS_IFORK_NEXTENTS(ip, whichfork) >
                        XFS_IFORK_MAXEXT(ip, whichfork);
}

/*
 * Check if the inode should be converted to extent format.
 */
static inline bool xfs_bmap_wants_extents(struct xfs_inode *ip, int whichfork)
{
        return XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE &&
                XFS_IFORK_NEXTENTS(ip, whichfork) <=
                        XFS_IFORK_MAXEXT(ip, whichfork);
}

/*
 * Update the record referred to by cur to the value given
 * by [off, bno, len, state].
 * This either works (return 0) or gets an EFSCORRUPTED error.
 */
STATIC int
xfs_bmbt_update(
        struct xfs_btree_cur    *cur,
        xfs_fileoff_t           off,
        xfs_fsblock_t           bno,
        xfs_filblks_t           len,
        xfs_exntst_t            state)
{
        union xfs_btree_rec     rec;

        xfs_bmbt_disk_set_allf(&rec.bmbt, off, bno, len, state);
        return xfs_btree_update(cur, &rec);
}

/*
 * Compute the worst-case number of indirect blocks that will be used
 * for ip's delayed extent of length "len".
 */
STATIC xfs_filblks_t
xfs_bmap_worst_indlen(
        xfs_inode_t     *ip,            /* incore inode pointer */
        xfs_filblks_t   len)            /* delayed extent length */
{
        int             level;          /* btree level number */
        int             maxrecs;        /* maximum record count at this level */
        xfs_mount_t     *mp;            /* mount structure */
        xfs_filblks_t   rval;           /* return value */

        mp = ip->i_mount;
        maxrecs = mp->m_bmap_dmxr[0];
        for (level = 0, rval = 0;
             level < XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK);
             level++) {
                len += maxrecs - 1;
                do_div(len, maxrecs);
                rval += len;
                if (len == 1)
                        return rval + XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) -
                                level - 1;
                if (level == 0)
                        maxrecs = mp->m_bmap_dmxr[1];
        }
        return rval;
}

/*
 * Calculate the default attribute fork offset for newly created inodes.
 */
uint
xfs_default_attroffset(
        struct xfs_inode        *ip)
{
        struct xfs_mount        *mp = ip->i_mount;
        uint                    offset;

        if (mp->m_sb.sb_inodesize == 256) {
                offset = XFS_LITINO(mp, ip->i_d.di_version) -
                                XFS_BMDR_SPACE_CALC(MINABTPTRS);
        } else {
                offset = XFS_BMDR_SPACE_CALC(6 * MINABTPTRS);
        }

        ASSERT(offset < XFS_LITINO(mp, ip->i_d.di_version));
        return offset;
}

/*
 * Helper routine to reset inode di_forkoff field when switching
 * attribute fork from local to extent format - we reset it where
 * possible to make space available for inline data fork extents.
 */
STATIC void
xfs_bmap_forkoff_reset(
        xfs_mount_t     *mp,
        xfs_inode_t     *ip,
        int             whichfork)
{
        if (whichfork == XFS_ATTR_FORK &&
            ip->i_d.di_format != XFS_DINODE_FMT_DEV &&
            ip->i_d.di_format != XFS_DINODE_FMT_UUID &&
            ip->i_d.di_format != XFS_DINODE_FMT_BTREE) {
                uint    dfl_forkoff = xfs_default_attroffset(ip) >> 3;

                if (dfl_forkoff > ip->i_d.di_forkoff)
                        ip->i_d.di_forkoff = dfl_forkoff;
        }
}

/*
 * Extent tree block counting routines.
 */

/*
 * Count leaf blocks given a range of extent records.
 */
STATIC void
xfs_bmap_count_leaves(
        xfs_ifork_t             *ifp,
        xfs_extnum_t            idx,
        int                     numrecs,
        int                     *count)
{
        int             b;

        for (b = 0; b < numrecs; b++) {
                xfs_bmbt_rec_host_t *frp = xfs_iext_get_ext(ifp, idx + b);
                *count += xfs_bmbt_get_blockcount(frp);
        }
}

/*
 * Count leaf blocks given a range of extent records originally
 * in btree format.
 */
STATIC void
xfs_bmap_disk_count_leaves(
        struct xfs_mount        *mp,
        struct xfs_btree_block  *block,
        int                     numrecs,
        int                     *count)
{
        int             b;
        xfs_bmbt_rec_t  *frp;

        for (b = 1; b <= numrecs; b++) {
                frp = XFS_BMBT_REC_ADDR(mp, block, b);
                *count += xfs_bmbt_disk_get_blockcount(frp);
        }
}

/*
 * Recursively walks each level of a btree
 * to count total fsblocks is use.
 */
STATIC int                                     /* error */
xfs_bmap_count_tree(
        xfs_mount_t     *mp,            /* file system mount point */
        xfs_trans_t     *tp,            /* transaction pointer */
        xfs_ifork_t     *ifp,           /* inode fork pointer */
        xfs_fsblock_t   blockno,        /* file system block number */
        int             levelin,        /* level in btree */
        int             *count)         /* Count of blocks */
{
        int                     error;
        xfs_buf_t               *bp, *nbp;
        int                     level = levelin;
        __be64                  *pp;
        xfs_fsblock_t           bno = blockno;
        xfs_fsblock_t           nextbno;
        struct xfs_btree_block  *block, *nextblock;
        int                     numrecs;

        error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp, XFS_BMAP_BTREE_REF,
                                                &xfs_bmbt_buf_ops);
        if (error)
                return error;
        *count += 1;
        block = XFS_BUF_TO_BLOCK(bp);

        if (--level) {
                /* Not at node above leaves, count this level of nodes */
                nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
                while (nextbno != NULLFSBLOCK) {
                        error = xfs_btree_read_bufl(mp, tp, nextbno, 0, &nbp,
                                                XFS_BMAP_BTREE_REF,
                                                &xfs_bmbt_buf_ops);
                        if (error)
                                return error;
                        *count += 1;
                        nextblock = XFS_BUF_TO_BLOCK(nbp);
                        nextbno = be64_to_cpu(nextblock->bb_u.l.bb_rightsib);
                        xfs_trans_brelse(tp, nbp);
                }

                /* Dive to the next level */
                pp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]);
                bno = be64_to_cpu(*pp);
                if (unlikely((error =
                     xfs_bmap_count_tree(mp, tp, ifp, bno, level, count)) < 0)) {
                        xfs_trans_brelse(tp, bp);
                        XFS_ERROR_REPORT("xfs_bmap_count_tree(1)",
                                         XFS_ERRLEVEL_LOW, mp);
                        return XFS_ERROR(EFSCORRUPTED);
                }
                xfs_trans_brelse(tp, bp);
        } else {
                /* count all level 1 nodes and their leaves */
                for (;;) {
                        nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
                        numrecs = be16_to_cpu(block->bb_numrecs);
                        xfs_bmap_disk_count_leaves(mp, block, numrecs, count);
                        xfs_trans_brelse(tp, bp);
                        if (nextbno == NULLFSBLOCK)
                                break;
                        bno = nextbno;
                        error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp,
                                                XFS_BMAP_BTREE_REF,
                                                &xfs_bmbt_buf_ops);
                        if (error)
                                return error;
                        *count += 1;
                        block = XFS_BUF_TO_BLOCK(bp);
                }
        }
        return 0;
}

/*
 * Count fsblocks of the given fork.
 */
int                                             /* error */
xfs_bmap_count_blocks(
        xfs_trans_t             *tp,            /* transaction pointer */
        xfs_inode_t             *ip,            /* incore inode */
        int                     whichfork,      /* data or attr fork */
        int                     *count)         /* out: count of blocks */
{
        struct xfs_btree_block  *block; /* current btree block */
        xfs_fsblock_t           bno;    /* block # of "block" */
        xfs_ifork_t             *ifp;   /* fork structure */
        int                     level;  /* btree level, for checking */
        xfs_mount_t             *mp;    /* file system mount structure */
        __be64                  *pp;    /* pointer to block address */

        bno = NULLFSBLOCK;
        mp = ip->i_mount;
        ifp = XFS_IFORK_PTR(ip, whichfork);
        if ( XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS ) {
                xfs_bmap_count_leaves(ifp, 0,
                        ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t),
                        count);
                return 0;
        }

        /*
         * Root level must use BMAP_BROOT_PTR_ADDR macro to get ptr out.
         */
        block = ifp->if_broot;
        level = be16_to_cpu(block->bb_level);
        ASSERT(level > 0);
        pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes);
        bno = be64_to_cpu(*pp);
        ASSERT(bno != NULLDFSBNO);
        ASSERT(XFS_FSB_TO_AGNO(mp, bno) < mp->m_sb.sb_agcount);
        ASSERT(XFS_FSB_TO_AGBNO(mp, bno) < mp->m_sb.sb_agblocks);

        if (unlikely(xfs_bmap_count_tree(mp, tp, ifp, bno, level, count) < 0)) {
                XFS_ERROR_REPORT("xfs_bmap_count_blocks(2)", XFS_ERRLEVEL_LOW,
                                 mp);
                return XFS_ERROR(EFSCORRUPTED);
        }

        return 0;
}

/*
 * Debug/sanity checking code
 */

STATIC int
xfs_bmap_sanity_check(
        struct xfs_mount        *mp,
        struct xfs_buf          *bp,
        int                     level)
{
        struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);

        if (block->bb_magic != cpu_to_be32(XFS_BMAP_CRC_MAGIC) &&
            block->bb_magic != cpu_to_be32(XFS_BMAP_MAGIC))
                return 0;

        if (be16_to_cpu(block->bb_level) != level ||
            be16_to_cpu(block->bb_numrecs) == 0 ||
            be16_to_cpu(block->bb_numrecs) > mp->m_bmap_dmxr[level != 0])
                return 0;

        return 1;
}

#ifdef DEBUG
STATIC struct xfs_buf *
xfs_bmap_get_bp(
        struct xfs_btree_cur    *cur,
        xfs_fsblock_t           bno)
{
        struct xfs_log_item_desc *lidp;
        int                     i;

        if (!cur)
                return NULL;

        for (i = 0; i < XFS_BTREE_MAXLEVELS; i++) {
                if (!cur->bc_bufs[i])
                        break;
                if (XFS_BUF_ADDR(cur->bc_bufs[i]) == bno)
                        return cur->bc_bufs[i];
        }

        /* Chase down all the log items to see if the bp is there */
        list_for_each_entry(lidp, &cur->bc_tp->t_items, lid_trans) {
                struct xfs_buf_log_item *bip;
                bip = (struct xfs_buf_log_item *)lidp->lid_item;
                if (bip->bli_item.li_type == XFS_LI_BUF &&
                    XFS_BUF_ADDR(bip->bli_buf) == bno)
                        return bip->bli_buf;
        }

        return NULL;
}

STATIC void
xfs_check_block(
        struct xfs_btree_block  *block,
        xfs_mount_t             *mp,
        int                     root,
        short                   sz)
{
        int                     i, j, dmxr;
        __be64                  *pp, *thispa;   /* pointer to block address */
        xfs_bmbt_key_t          *prevp, *keyp;

        ASSERT(be16_to_cpu(block->bb_level) > 0);

        prevp = NULL;
        for( i = 1; i <= xfs_btree_get_numrecs(block); i++) {
                dmxr = mp->m_bmap_dmxr[0];
                keyp = XFS_BMBT_KEY_ADDR(mp, block, i);

                if (prevp) {
                        ASSERT(be64_to_cpu(prevp->br_startoff) <
                               be64_to_cpu(keyp->br_startoff));
                }
                prevp = keyp;

                /*
                 * Compare the block numbers to see if there are dups.
                 */
                if (root)
                        pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, i, sz);
                else
                        pp = XFS_BMBT_PTR_ADDR(mp, block, i, dmxr);

                for (j = i+1; j <= be16_to_cpu(block->bb_numrecs); j++) {
                        if (root)
                                thispa = XFS_BMAP_BROOT_PTR_ADDR(mp, block, j, sz);
                        else
                                thispa = XFS_BMBT_PTR_ADDR(mp, block, j, dmxr);
                        if (*thispa == *pp) {
                                xfs_warn(mp, "%s: thispa(%d) == pp(%d) %Ld",
                                        __func__, j, i,
                                        (unsigned long long)be64_to_cpu(*thispa));
                                panic("%s: ptrs are equal in node\n",
                                        __func__);
                        }
                }
        }
}

/*
 * Check that the extents for the inode ip are in the right order in all
 * btree leaves.
 */

STATIC void
xfs_bmap_check_leaf_extents(
        xfs_btree_cur_t         *cur,   /* btree cursor or null */
        xfs_inode_t             *ip,            /* incore inode pointer */
        int                     whichfork)      /* data or attr fork */
{
        struct xfs_btree_block  *block; /* current btree block */
        xfs_fsblock_t           bno;    /* block # of "block" */
        xfs_buf_t               *bp;    /* buffer for "block" */
        int                     error;  /* error return value */
        xfs_extnum_t            i=0, j; /* index into the extents list */
        xfs_ifork_t             *ifp;   /* fork structure */
        int                     level;  /* btree level, for checking */
        xfs_mount_t             *mp;    /* file system mount structure */
        __be64                  *pp;    /* pointer to block address */
        xfs_bmbt_rec_t          *ep;    /* pointer to current extent */
        xfs_bmbt_rec_t          last = {0, 0}; /* last extent in prev block */
        xfs_bmbt_rec_t          *nextp; /* pointer to next extent */
        int                     bp_release = 0;

        if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE) {
                return;
        }

        bno = NULLFSBLOCK;
        mp = ip->i_mount;
        ifp = XFS_IFORK_PTR(ip, whichfork);
        block = ifp->if_broot;
        /*
         * Root level must use BMAP_BROOT_PTR_ADDR macro to get ptr out.
         */
        level = be16_to_cpu(block->bb_level);
        ASSERT(level > 0);
        xfs_check_block(block, mp, 1, ifp->if_broot_bytes);
        pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes);
        bno = be64_to_cpu(*pp);

        ASSERT(bno != NULLDFSBNO);
        ASSERT(XFS_FSB_TO_AGNO(mp, bno) < mp->m_sb.sb_agcount);
        ASSERT(XFS_FSB_TO_AGBNO(mp, bno) < mp->m_sb.sb_agblocks);

        /*
         * Go down the tree until leaf level is reached, following the first
         * pointer (leftmost) at each level.
         */
        while (level-- > 0) {
                /* See if buf is in cur first */
                bp_release = 0;
                bp = xfs_bmap_get_bp(cur, XFS_FSB_TO_DADDR(mp, bno));
                if (!bp) {
                        bp_release = 1;
                        error = xfs_btree_read_bufl(mp, NULL, bno, 0, &bp,
                                                XFS_BMAP_BTREE_REF,
                                                &xfs_bmbt_buf_ops);
                        if (error)
                                goto error_norelse;
                }
                block = XFS_BUF_TO_BLOCK(bp);
                XFS_WANT_CORRUPTED_GOTO(
                        xfs_bmap_sanity_check(mp, bp, level),
                        error0);
                if (level == 0)
                        break;

                /*
                 * Check this block for basic sanity (increasing keys and
                 * no duplicate blocks).
                 */

                xfs_check_block(block, mp, 0, 0);
                pp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]);
                bno = be64_to_cpu(*pp);
                XFS_WANT_CORRUPTED_GOTO(XFS_FSB_SANITY_CHECK(mp, bno), error0);
                if (bp_release) {
                        bp_release = 0;
                        xfs_trans_brelse(NULL, bp);
                }
        }

        /*
         * Here with bp and block set to the leftmost leaf node in the tree.
         */
        i = 0;

        /*
         * Loop over all leaf nodes checking that all extents are in the right order.
         */
        for (;;) {
                xfs_fsblock_t   nextbno;
                xfs_extnum_t    num_recs;


                num_recs = xfs_btree_get_numrecs(block);

                /*
                 * Read-ahead the next leaf block, if any.
                 */

                nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);

                /*
                 * Check all the extents to make sure they are OK.
                 * If we had a previous block, the last entry should
                 * conform with the first entry in this one.
                 */

                ep = XFS_BMBT_REC_ADDR(mp, block, 1);
                if (i) {
                        ASSERT(xfs_bmbt_disk_get_startoff(&last) +
                               xfs_bmbt_disk_get_blockcount(&last) <=
                               xfs_bmbt_disk_get_startoff(ep));
                }
                for (j = 1; j < num_recs; j++) {
                        nextp = XFS_BMBT_REC_ADDR(mp, block, j + 1);
                        ASSERT(xfs_bmbt_disk_get_startoff(ep) +
                               xfs_bmbt_disk_get_blockcount(ep) <=
                               xfs_bmbt_disk_get_startoff(nextp));
                        ep = nextp;
                }

                last = *ep;
                i += num_recs;
                if (bp_release) {
                        bp_release = 0;
                        xfs_trans_brelse(NULL, bp);
                }
                bno = nextbno;
                /*
                 * If we've reached the end, stop.
                 */
                if (bno == NULLFSBLOCK)
                        break;

                bp_release = 0;
                bp = xfs_bmap_get_bp(cur, XFS_FSB_TO_DADDR(mp, bno));
                if (!bp) {
                        bp_release = 1;
                        error = xfs_btree_read_bufl(mp, NULL, bno, 0, &bp,
                                                XFS_BMAP_BTREE_REF,
                                                &xfs_bmbt_buf_ops);
                        if (error)
                                goto error_norelse;
                }
                block = XFS_BUF_TO_BLOCK(bp);
        }
        if (bp_release) {
                bp_release = 0;
                xfs_trans_brelse(NULL, bp);
        }
        return;

error0:
        xfs_warn(mp, "%s: at error0", __func__);
        if (bp_release)
                xfs_trans_brelse(NULL, bp);
error_norelse:
        xfs_warn(mp, "%s: BAD after btree leaves for %d extents",
                __func__, i);
        panic("%s: CORRUPTED BTREE OR SOMETHING", __func__);
        return;
}

/*
 * Add bmap trace insert entries for all the contents of the extent records.
 */
void
xfs_bmap_trace_exlist(
        xfs_inode_t     *ip,            /* incore inode pointer */
        xfs_extnum_t    cnt,            /* count of entries in the list */
        int             whichfork,      /* data or attr fork */
        unsigned long   caller_ip)
{
        xfs_extnum_t    idx;            /* extent record index */
        xfs_ifork_t     *ifp;           /* inode fork pointer */
        int             state = 0;

        if (whichfork == XFS_ATTR_FORK)
                state |= BMAP_ATTRFORK;

        ifp = XFS_IFORK_PTR(ip, whichfork);
        ASSERT(cnt == (ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t)));
        for (idx = 0; idx < cnt; idx++)
                trace_xfs_extlist(ip, idx, whichfork, caller_ip);
}

/*
 * Validate that the bmbt_irecs being returned from bmapi are valid
 * given the callers original parameters.  Specifically check the
 * ranges of the returned irecs to ensure that they only extent beyond
 * the given parameters if the XFS_BMAPI_ENTIRE flag was set.
 */
STATIC void
xfs_bmap_validate_ret(
        xfs_fileoff_t           bno,
        xfs_filblks_t           len,
        int                     flags,
        xfs_bmbt_irec_t         *mval,
        int                     nmap,
        int                     ret_nmap)
{
        int                     i;              /* index to map values */

        ASSERT(ret_nmap <= nmap);

        for (i = 0; i < ret_nmap; i++) {
                ASSERT(mval[i].br_blockcount > 0);
                if (!(flags & XFS_BMAPI_ENTIRE)) {
                        ASSERT(mval[i].br_startoff >= bno);
                        ASSERT(mval[i].br_blockcount <= len);
                        ASSERT(mval[i].br_startoff + mval[i].br_blockcount <=
                               bno + len);
                } else {
                        ASSERT(mval[i].br_startoff < bno + len);
                        ASSERT(mval[i].br_startoff + mval[i].br_blockcount >
                               bno);
                }
                ASSERT(i == 0 ||
                       mval[i - 1].br_startoff + mval[i - 1].br_blockcount ==
                       mval[i].br_startoff);
                ASSERT(mval[i].br_startblock != DELAYSTARTBLOCK &&
                       mval[i].br_startblock != HOLESTARTBLOCK);
                ASSERT(mval[i].br_state == XFS_EXT_NORM ||
                       mval[i].br_state == XFS_EXT_UNWRITTEN);
        }
}

#else
#define xfs_bmap_check_leaf_extents(cur, ip, whichfork)         do { } while (0)
#define xfs_bmap_validate_ret(bno,len,flags,mval,onmap,nmap)
#endif /* DEBUG */

/*
 * bmap free list manipulation functions
 */

/*
 * Add the extent to the list of extents to be free at transaction end.
 * The list is maintained sorted (by block number).
 */
void
xfs_bmap_add_free(
        xfs_fsblock_t           bno,            /* fs block number of extent */
        xfs_filblks_t           len,            /* length of extent */
        xfs_bmap_free_t         *flist,         /* list of extents */
        xfs_mount_t             *mp)            /* mount point structure */
{
        xfs_bmap_free_item_t    *cur;           /* current (next) element */
        xfs_bmap_free_item_t    *new;           /* new element */
        xfs_bmap_free_item_t    *prev;          /* previous element */
#ifdef DEBUG
        xfs_agnumber_t          agno;
        xfs_agblock_t           agbno;

        ASSERT(bno != NULLFSBLOCK);
        ASSERT(len > 0);
        ASSERT(len <= MAXEXTLEN);
        ASSERT(!isnullstartblock(bno));
        agno = XFS_FSB_TO_AGNO(mp, bno);
        agbno = XFS_FSB_TO_AGBNO(mp, bno);
        ASSERT(agno < mp->m_sb.sb_agcount);
        ASSERT(agbno < mp->m_sb.sb_agblocks);
        ASSERT(len < mp->m_sb.sb_agblocks);
        ASSERT(agbno + len <= mp->m_sb.sb_agblocks);
#endif
        ASSERT(xfs_bmap_free_item_zone != NULL);
        new = kmem_zone_alloc(xfs_bmap_free_item_zone, KM_SLEEP);
        new->xbfi_startblock = bno;
        new->xbfi_blockcount = (xfs_extlen_t)len;
        for (prev = NULL, cur = flist->xbf_first;
             cur != NULL;
             prev = cur, cur = cur->xbfi_next) {
                if (cur->xbfi_startblock >= bno)
                        break;
        }
        if (prev)
                prev->xbfi_next = new;
        else
                flist->xbf_first = new;
        new->xbfi_next = cur;
        flist->xbf_count++;
}

/*
 * Remove the entry "free" from the free item list.  Prev points to the
 * previous entry, unless "free" is the head of the list.
 */
STATIC void
xfs_bmap_del_free(
        xfs_bmap_free_t         *flist, /* free item list header */
        xfs_bmap_free_item_t    *prev,  /* previous item on list, if any */
        xfs_bmap_free_item_t    *free)  /* list item to be freed */
{
        if (prev)
                prev->xbfi_next = free->xbfi_next;
        else
                flist->xbf_first = free->xbfi_next;
        flist->xbf_count--;
        kmem_zone_free(xfs_bmap_free_item_zone, free);
}


/*
 * Routine to be called at transaction's end by xfs_bmapi, xfs_bunmapi
 * caller.  Frees all the extents that need freeing, which must be done
 * last due to locking considerations.  We never free any extents in
 * the first transaction.
 *
 * Return 1 if the given transaction was committed and a new one
 * started, and 0 otherwise in the committed parameter.
 */
int                                             /* error */
xfs_bmap_finish(
        xfs_trans_t             **tp,           /* transaction pointer addr */
        xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
        int                     *committed)     /* xact committed or not */
{
        xfs_efd_log_item_t      *efd;           /* extent free data */
        xfs_efi_log_item_t      *efi;           /* extent free intention */
        int                     error;          /* error return value */
        xfs_bmap_free_item_t    *free;          /* free extent item */
        unsigned int            logres;         /* new log reservation */
        unsigned int            logcount;       /* new log count */
        xfs_mount_t             *mp;            /* filesystem mount structure */
        xfs_bmap_free_item_t    *next;          /* next item on free list */
        xfs_trans_t             *ntp;           /* new transaction pointer */

        ASSERT((*tp)->t_flags & XFS_TRANS_PERM_LOG_RES);
        if (flist->xbf_count == 0) {
                *committed = 0;
                return 0;
        }
        ntp = *tp;
        efi = xfs_trans_get_efi(ntp, flist->xbf_count);
        for (free = flist->xbf_first; free; free = free->xbfi_next)
                xfs_trans_log_efi_extent(ntp, efi, free->xbfi_startblock,
                        free->xbfi_blockcount);
        logres = ntp->t_log_res;
        logcount = ntp->t_log_count;
        ntp = xfs_trans_dup(*tp);
        error = xfs_trans_commit(*tp, 0);
        *tp = ntp;
        *committed = 1;
        /*
         * We have a new transaction, so we should return committed=1,
         * even though we're returning an error.
         */
        if (error)
                return error;

        /*
         * transaction commit worked ok so we can drop the extra ticket
         * reference that we gained in xfs_trans_dup()
         */
        xfs_log_ticket_put(ntp->t_ticket);

        if ((error = xfs_trans_reserve(ntp, 0, logres, 0, XFS_TRANS_PERM_LOG_RES,
                        logcount)))
                return error;
        efd = xfs_trans_get_efd(ntp, efi, flist->xbf_count);
        for (free = flist->xbf_first; free != NULL; free = next) {
                next = free->xbfi_next;
                if ((error = xfs_free_extent(ntp, free->xbfi_startblock,
                                free->xbfi_blockcount))) {
                        /*
                         * The bmap free list will be cleaned up at a
                         * higher level.  The EFI will be canceled when
                         * this transaction is aborted.
                         * Need to force shutdown here to make sure it
                         * happens, since this transaction may not be
                         * dirty yet.
                         */
                        mp = ntp->t_mountp;
                        if (!XFS_FORCED_SHUTDOWN(mp))
                                xfs_force_shutdown(mp,
                                                   (error == EFSCORRUPTED) ?
                                                   SHUTDOWN_CORRUPT_INCORE :
                                                   SHUTDOWN_META_IO_ERROR);
                        return error;
                }
                xfs_trans_log_efd_extent(ntp, efd, free->xbfi_startblock,
                        free->xbfi_blockcount);
                xfs_bmap_del_free(flist, NULL, free);
        }
        return 0;
}

/*
 * Free up any items left in the list.
 */
void
xfs_bmap_cancel(
        xfs_bmap_free_t         *flist) /* list of bmap_free_items */
{
        xfs_bmap_free_item_t    *free;  /* free list item */
        xfs_bmap_free_item_t    *next;

        if (flist->xbf_count == 0)
                return;
        ASSERT(flist->xbf_first != NULL);
        for (free = flist->xbf_first; free; free = next) {
                next = free->xbfi_next;
                xfs_bmap_del_free(flist, NULL, free);
        }
        ASSERT(flist->xbf_count == 0);
}

/*
 * Inode fork format manipulation functions
 */

/*
 * Transform a btree format file with only one leaf node, where the
 * extents list will fit in the inode, into an extents format file.
 * Since the file extents are already in-core, all we have to do is
 * give up the space for the btree root and pitch the leaf block.
 */
STATIC int                              /* error */
xfs_bmap_btree_to_extents(
        xfs_trans_t             *tp,    /* transaction pointer */
        xfs_inode_t             *ip,    /* incore inode pointer */
        xfs_btree_cur_t         *cur,   /* btree cursor */
        int                     *logflagsp, /* inode logging flags */
        int                     whichfork)  /* data or attr fork */
{
        /* REFERENCED */
        struct xfs_btree_block  *cblock;/* child btree block */
        xfs_fsblock_t           cbno;   /* child block number */
        xfs_buf_t               *cbp;   /* child block's buffer */
        int                     error;  /* error return value */
        xfs_ifork_t             *ifp;   /* inode fork data */
        xfs_mount_t             *mp;    /* mount point structure */
        __be64                  *pp;    /* ptr to block address */
        struct xfs_btree_block  *rblock;/* root btree block */

        mp = ip->i_mount;
        ifp = XFS_IFORK_PTR(ip, whichfork);
        ASSERT(ifp->if_flags & XFS_IFEXTENTS);
        ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE);
        rblock = ifp->if_broot;
        ASSERT(be16_to_cpu(rblock->bb_level) == 1);
        ASSERT(be16_to_cpu(rblock->bb_numrecs) == 1);
        ASSERT(xfs_bmbt_maxrecs(mp, ifp->if_broot_bytes, 0) == 1);
        pp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, ifp->if_broot_bytes);
        cbno = be64_to_cpu(*pp);
        *logflagsp = 0;
#ifdef DEBUG
        if ((error = xfs_btree_check_lptr(cur, cbno, 1)))
                return error;
#endif
        error = xfs_btree_read_bufl(mp, tp, cbno, 0, &cbp, XFS_BMAP_BTREE_REF,
                                &xfs_bmbt_buf_ops);
        if (error)
                return error;
        cblock = XFS_BUF_TO_BLOCK(cbp);
        if ((error = xfs_btree_check_block(cur, cblock, 0, cbp)))
                return error;
        xfs_bmap_add_free(cbno, 1, cur->bc_private.b.flist, mp);
        ip->i_d.di_nblocks--;
        xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
        xfs_trans_binval(tp, cbp);
        if (cur->bc_bufs[0] == cbp)

                cur->bc_bufs[0] = NULL;
        xfs_iroot_realloc(ip, -1, whichfork);
        ASSERT(ifp->if_broot == NULL);
        ASSERT((ifp->if_flags & XFS_IFBROOT) == 0);
        XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_EXTENTS);
        *logflagsp = XFS_ILOG_CORE | xfs_ilog_fext(whichfork);
        return 0;
}

/*
 * Convert an extents-format file into a btree-format file.
 * The new file will have a root block (in the inode) and a single child block.
 */
STATIC int                                      /* error */
xfs_bmap_extents_to_btree(
        xfs_trans_t             *tp,            /* transaction pointer */
        xfs_inode_t             *ip,            /* incore inode pointer */
        xfs_fsblock_t           *firstblock,    /* first-block-allocated */
        xfs_bmap_free_t         *flist,         /* blocks freed in xaction */
        xfs_btree_cur_t         **curp,         /* cursor returned to caller */
        int                     wasdel,         /* converting a delayed alloc */
        int                     *logflagsp,     /* inode logging flags */
        int                     whichfork)      /* data or attr fork */
{
        struct xfs_btree_block  *ablock;        /* allocated (child) bt block */
        xfs_buf_t               *abp;           /* buffer for ablock */
        xfs_alloc_arg_t         args;           /* allocation arguments */
        xfs_bmbt_rec_t          *arp;           /* child record pointer */
        struct xfs_btree_block  *block;         /* btree root block */
        xfs_btree_cur_t         *cur;           /* bmap btree cursor */
        xfs_bmbt_rec_host_t     *ep;            /* extent record pointer */
        int                     error;          /* error return value */
        xfs_extnum_t            i, cnt;         /* extent record index */
        xfs_ifork_t             *ifp;           /* inode fork pointer */
        xfs_bmbt_key_t          *kp;            /* root block key pointer */
        xfs_mount_t             *mp;            /* mount structure */
        xfs_extnum_t            nextents;       /* number of file extents */
        xfs_bmbt_ptr_t          *pp;            /* root block address pointer */

        mp = ip->i_mount;
        ifp = XFS_IFORK_PTR(ip, whichfork);
        ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS);

        /*
         * Make space in the inode incore.
         */
        xfs_iroot_realloc(ip, 1, whichfork);
        ifp->if_flags |= XFS_IFBROOT;

        /*
         * Fill in the root.
         */
        block = ifp->if_broot;
        if (xfs_sb_version_hascrc(&mp->m_sb))
                xfs_btree_init_block_int(mp, block, XFS_BUF_DADDR_NULL,
                                 XFS_BMAP_CRC_MAGIC, 1, 1, ip->i_ino,
                                 XFS_BTREE_LONG_PTRS | XFS_BTREE_CRC_BLOCKS);
        else
                xfs_btree_init_block_int(mp, block, XFS_BUF_DADDR_NULL,
                                 XFS_BMAP_MAGIC, 1, 1, ip->i_ino,
                                 XFS_BTREE_LONG_PTRS);

        /*
         * Need a cursor.  Can't allocate until bb_level is filled in.
         */
        cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
        cur->bc_private.b.firstblock = *firstblock;
        cur->bc_private.b.flist = flist;
        cur->bc_private.b.flags = wasdel ? XFS_BTCUR_BPRV_WASDEL : 0;
        /*
         * Convert to a btree with two levels, one record in root.
         */
        XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_BTREE);
        memset(&args, 0, sizeof(args));
        args.tp = tp;
        args.mp = mp;
        args.firstblock = *firstblock;
        if (*firstblock == NULLFSBLOCK) {
                args.type = XFS_ALLOCTYPE_START_BNO;
                args.fsbno = XFS_INO_TO_FSB(mp, ip->i_ino);
        } else if (flist->xbf_low) {
                args.type = XFS_ALLOCTYPE_START_BNO;
                args.fsbno = *firstblock;
        } else {
                args.type = XFS_ALLOCTYPE_NEAR_BNO;
                args.fsbno = *firstblock;
        }
        args.minlen = args.maxlen = args.prod = 1;
        args.wasdel = wasdel;
        *logflagsp = 0;
        if ((error = xfs_alloc_vextent(&args))) {
                xfs_iroot_realloc(ip, -1, whichfork);
                xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
                return error;
        }
        /*
         * Allocation can't fail, the space was reserved.
         */
        ASSERT(args.fsbno != NULLFSBLOCK);
        ASSERT(*firstblock == NULLFSBLOCK ||
               args.agno == XFS_FSB_TO_AGNO(mp, *firstblock) ||
               (flist->xbf_low &&
                args.agno > XFS_FSB_TO_AGNO(mp, *firstblock)));
        *firstblock = cur->bc_private.b.firstblock = args.fsbno;
        cur->bc_private.b.allocated++;
        ip->i_d.di_nblocks++;
        xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, 1L);
        abp = xfs_btree_get_bufl(mp, tp, args.fsbno, 0);
        /*
         * Fill in the child block.
         */
        abp->b_ops = &xfs_bmbt_buf_ops;
        ablock = XFS_BUF_TO_BLOCK(abp);
        if (xfs_sb_version_hascrc(&mp->m_sb))
                xfs_btree_init_block_int(mp, ablock, abp->b_bn,
                                XFS_BMAP_CRC_MAGIC, 0, 0, ip->i_ino,
                                XFS_BTREE_LONG_PTRS | XFS_BTREE_CRC_BLOCKS);
        else
                xfs_btree_init_block_int(mp, ablock, abp->b_bn,
                                XFS_BMAP_MAGIC, 0, 0, ip->i_ino,
                                XFS_BTREE_LONG_PTRS);

        arp = XFS_BMBT_REC_ADDR(mp, ablock, 1);
        nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
        for (cnt = i = 0; i < nextents; i++) {
                ep = xfs_iext_get_ext(ifp, i);
                if (!isnullstartblock(xfs_bmbt_get_startblock(ep))) {
                        arp->l0 = cpu_to_be64(ep->l0);
                        arp->l1 = cpu_to_be64(ep->l1);
                        arp++; cnt++;
                }
        }
        ASSERT(cnt == XFS_IFORK_NEXTENTS(ip, whichfork));
        xfs_btree_set_numrecs(ablock, cnt);

        /*
         * Fill in the root key and pointer.
         */
        kp = XFS_BMBT_KEY_ADDR(mp, block, 1);
        arp = XFS_BMBT_REC_ADDR(mp, ablock, 1);
        kp->br_startoff = cpu_to_be64(xfs_bmbt_disk_get_startoff(arp));
        pp = XFS_BMBT_PTR_ADDR(mp, block, 1, xfs_bmbt_get_maxrecs(cur,
                                                be16_to_cpu(block->bb_level)));
        *pp = cpu_to_be64(args.fsbno);

        /*
         * Do all this logging at the end so that
         * the root is at the right level.
         */
        xfs_btree_log_block(cur, abp, XFS_BB_ALL_BITS);
        xfs_btree_log_recs(cur, abp, 1, be16_to_cpu(ablock->bb_numrecs));
        ASSERT(*curp == NULL);
        *curp = cur;
        *logflagsp = XFS_ILOG_CORE | xfs_ilog_fbroot(whichfork);
        return 0;
}

/*
 * Convert a local file to an extents file.
 * This code is out of bounds for data forks of regular files,
 * since the file data needs to get logged so things will stay consistent.
 * (The bmap-level manipulations are ok, though).
 */
void
xfs_bmap_local_to_extents_empty(
        struct xfs_inode        *ip,
        int                     whichfork)
{
        struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);

        ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL);
        ASSERT(ifp->if_bytes == 0);
        ASSERT(XFS_IFORK_NEXTENTS(ip, whichfork) == 0);

        xfs_bmap_forkoff_reset(ip->i_mount, ip, whichfork);
        ifp->if_flags &= ~XFS_IFINLINE;
        ifp->if_flags |= XFS_IFEXTENTS;
        XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_EXTENTS);
}


STATIC int                              /* error */
xfs_bmap_local_to_extents(
        xfs_trans_t     *tp,            /* transaction pointer */
        xfs_inode_t     *ip,            /* incore inode pointer */
        xfs_fsblock_t   *firstblock,    /* first block allocated in xaction */
        xfs_extlen_t    total,          /* total blocks needed by transaction */
        int             *logflagsp,     /* inode logging flags */
        int             whichfork,
        void            (*init_fn)(struct xfs_trans *tp,
                                   struct xfs_buf *bp,
                                   struct xfs_inode *ip,
                                   struct xfs_ifork *ifp))
{
        int             error = 0;
        int             flags;          /* logging flags returned */
        xfs_ifork_t     *ifp;           /* inode fork pointer */
        xfs_alloc_arg_t args;           /* allocation arguments */
        xfs_buf_t       *bp;            /* buffer for extent block */
        xfs_bmbt_rec_host_t *ep;        /* extent record pointer */

        /*
         * We don't want to deal with the case of keeping inode data inline yet.
         * So sending the data fork of a regular inode is invalid.
         */
        ASSERT(!(S_ISREG(ip->i_d.di_mode) && whichfork == XFS_DATA_FORK));
        ifp = XFS_IFORK_PTR(ip, whichfork);
        ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL);

        if (!ifp->if_bytes) {
                xfs_bmap_local_to_extents_empty(ip, whichfork);
                flags = XFS_ILOG_CORE;
                goto done;
        }

        flags = 0;
        error = 0;
        ASSERT((ifp->if_flags & (XFS_IFINLINE|XFS_IFEXTENTS|XFS_IFEXTIREC)) ==
                                                                XFS_IFINLINE);
        memset(&args, 0, sizeof(args));
        args.tp = tp;
        args.mp = ip->i_mount;
        args.firstblock = *firstblock;
        /*
         * Allocate a block.  We know we need only one, since the
         * file currently fits in an inode.
         */
        if (*firstblock == NULLFSBLOCK) {
                args.fsbno = XFS_INO_TO_FSB(args.mp, ip->i_ino);
                args.type = XFS_ALLOCTYPE_START_BNO;
        } else {
                args.fsbno = *firstblock;
                args.type = XFS_ALLOCTYPE_NEAR_BNO;
        }
        args.total = total;
        args.minlen = args.maxlen = args.prod = 1;
        error = xfs_alloc_vextent(&args);
        if (error)
                goto done;

        /* Can't fail, the space was reserved. */
        ASSERT(args.fsbno != NULLFSBLOCK);
        ASSERT(args.len == 1);
        *firstblock = args.fsbno;
        bp = xfs_btree_get_bufl(args.mp, tp, args.fsbno, 0);

        /* initialise the block and copy the data */
        init_fn(tp, bp, ip, ifp);

        /* account for the change in fork size and log everything */
        xfs_trans_log_buf(tp, bp, 0, ifp->if_bytes - 1);
        xfs_idata_realloc(ip, -ifp->if_bytes, whichfork);
        xfs_bmap_local_to_extents_empty(ip, whichfork);
        flags |= XFS_ILOG_CORE;

        xfs_iext_add(ifp, 0, 1);
        ep = xfs_iext_get_ext(ifp, 0);
        xfs_bmbt_set_allf(ep, 0, args.fsbno, 1, XFS_EXT_NORM);
        trace_xfs_bmap_post_update(ip, 0,
                        whichfork == XFS_ATTR_FORK ? BMAP_ATTRFORK : 0,
                        _THIS_IP_);
        XFS_IFORK_NEXT_SET(ip, whichfork, 1);
        ip->i_d.di_nblocks = 1;
        xfs_trans_mod_dquot_byino(tp, ip,
                XFS_TRANS_DQ_BCOUNT, 1L);
        flags |= xfs_ilog_fext(whichfork);

done:
        *logflagsp = flags;
        return error;
}

/*
 * Called from xfs_bmap_add_attrfork to handle btree format files.
 */
STATIC int                                      /* error */
xfs_bmap_add_attrfork_btree(
        xfs_trans_t             *tp,            /* transaction pointer */
        xfs_inode_t             *ip,            /* incore inode pointer */
        xfs_fsblock_t           *firstblock,    /* first block allocated */
        xfs_bmap_free_t         *flist,         /* blocks to free at commit */
        int                     *flags)         /* inode logging flags */
{
        xfs_btree_cur_t         *cur;           /* btree cursor */
        int                     error;          /* error return value */
        xfs_mount_t             *mp;            /* file system mount struct */
        int                     stat;           /* newroot status */

        mp = ip->i_mount;
        if (ip->i_df.if_broot_bytes <= XFS_IFORK_DSIZE(ip))
                *flags |= XFS_ILOG_DBROOT;
        else {
                cur = xfs_bmbt_init_cursor(mp, tp, ip, XFS_DATA_FORK);
                cur->bc_private.b.flist = flist;
                cur->bc_private.b.firstblock = *firstblock;
                if ((error = xfs_bmbt_lookup_ge(cur, 0, 0, 0, &stat)))
                        goto error0;
                /* must be at least one entry */
                XFS_WANT_CORRUPTED_GOTO(stat == 1, error0);
                if ((error = xfs_btree_new_iroot(cur, flags, &stat)))
                        goto error0;
                if (stat == 0) {
                        xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
                        return XFS_ERROR(ENOSPC);
                }
                *firstblock = cur->bc_private.b.firstblock;
                cur->bc_private.b.allocated = 0;
                xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
        }
        return 0;
error0:
        xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
        return error;
}

/*
 * Called from xfs_bmap_add_attrfork to handle extents format files.
 */
STATIC int                                      /* error */
xfs_bmap_add_attrfork_extents(
        xfs_trans_t             *tp,            /* transaction pointer */
        xfs_inode_t             *ip,            /* incore inode pointer */
        xfs_fsblock_t           *firstblock,    /* first block allocated */
        xfs_bmap_free_t         *flist,         /* blocks to free at commit */
        int                     *flags)         /* inode logging flags */
{
        xfs_btree_cur_t         *cur;           /* bmap btree cursor */
        int                     error;          /* error return value */

        if (ip->i_d.di_nextents * sizeof(xfs_bmbt_rec_t) <= XFS_IFORK_DSIZE(ip))
                return 0;
        cur = NULL;
        error = xfs_bmap_extents_to_btree(tp, ip, firstblock, flist, &cur, 0,
                flags, XFS_DATA_FORK);
        if (cur) {
                cur->bc_private.b.allocated = 0;
                xfs_btree_del_cursor(cur,
                        error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
        }
        return error;
}

/*
 * Called from xfs_bmap_add_attrfork to handle local format files. Each
 * different data fork content type needs a different callout to do the
 * conversion. Some are basic and only require special block initialisation
 * callouts for the data formating, others (directories) are so specialised they
 * handle everything themselves.
 *
 * XXX (dgc): investigate whether directory conversion can use the generic
 * formatting callout. It should be possible - it's just a very complex
 * formatter.
 */
STATIC int                                      /* error */
xfs_bmap_add_attrfork_local(
        xfs_trans_t             *tp,            /* transaction pointer */
        xfs_inode_t             *ip,            /* incore inode pointer */
        xfs_fsblock_t           *firstblock,    /* first block allocated */
        xfs_bmap_free_t         *flist,         /* blocks to free at commit */
        int                     *flags)         /* inode logging flags */
{
        xfs_da_args_t           dargs;          /* args for dir/attr code */

        if (ip->i_df.if_bytes <= XFS_IFORK_DSIZE(ip))
                return 0;

        if (S_ISDIR(ip->i_d.di_mode)) {
                memset(&dargs, 0, sizeof(dargs));
                dargs.dp = ip;
                dargs.firstblock = firstblock;
                dargs.flist = flist;
                dargs.total = ip->i_mount->m_dirblkfsbs;
                dargs.whichfork = XFS_DATA_FORK;
                dargs.trans = tp;
                return xfs_dir2_sf_to_block(&dargs);
        }

        if (S_ISLNK(ip->i_d.di_mode))
                return xfs_bmap_local_to_extents(tp, ip, firstblock, 1,
                                                 flags, XFS_DATA_FORK,
                                                 xfs_symlink_local_to_remote);

        /* should only be called for types that support local format data */
        ASSERT(0);
        return EFSCORRUPTED;
}

/*
 * Convert inode from non-attributed to attributed.
 * Must not be in a transaction, ip must not be locked.
 */
int                                             /* error code */
xfs_bmap_add_attrfork(
        xfs_inode_t             *ip,            /* incore inode pointer */
        int                     size,           /* space new attribute needs */
        int                     rsvd)           /* xact may use reserved blks */
{
        xfs_fsblock_t           firstblock;     /* 1st block/ag allocated */
        xfs_bmap_free_t         flist;          /* freed extent records */
        xfs_mount_t             *mp;            /* mount structure */
        xfs_trans_t             *tp;            /* transaction pointer */
        int                     blks;           /* space reservation */
        int                     version = 1;    /* superblock attr version */
        int                     committed;      /* xaction was committed */
        int                     logflags;       /* logging flags */
        int                     error;          /* error return value */

        ASSERT(XFS_IFORK_Q(ip) == 0);

        mp = ip->i_mount;
        ASSERT(!XFS_NOT_DQATTACHED(mp, ip));
        tp = xfs_trans_alloc(mp, XFS_TRANS_ADDAFORK);
        blks = XFS_ADDAFORK_SPACE_RES(mp);
        if (rsvd)
                tp->t_flags |= XFS_TRANS_RESERVE;
        if ((error = xfs_trans_reserve(tp, blks, XFS_ADDAFORK_LOG_RES(mp), 0,
                        XFS_TRANS_PERM_LOG_RES, XFS_ADDAFORK_LOG_COUNT)))
                goto error0;
        xfs_ilock(ip, XFS_ILOCK_EXCL);
        error = xfs_trans_reserve_quota_nblks(tp, ip, blks, 0, rsvd ?
                        XFS_QMOPT_RES_REGBLKS | XFS_QMOPT_FORCE_RES :
                        XFS_QMOPT_RES_REGBLKS);
        if (error) {
                xfs_iunlock(ip, XFS_ILOCK_EXCL);
                xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES);
                return error;
        }
        if (XFS_IFORK_Q(ip))
                goto error1;
        if (ip->i_d.di_aformat != XFS_DINODE_FMT_EXTENTS) {
                /*
                 * For inodes coming from pre-6.2 filesystems.
                 */
                ASSERT(ip->i_d.di_aformat == 0);
                ip->i_d.di_aformat = XFS_DINODE_FMT_EXTENTS;
        }
        ASSERT(ip->i_d.di_anextents == 0);

        xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
        xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

        switch (ip->i_d.di_format) {
        case XFS_DINODE_FMT_DEV:
                ip->i_d.di_forkoff = roundup(sizeof(xfs_dev_t), 8) >> 3;
                break;
        case XFS_DINODE_FMT_UUID:
                ip->i_d.di_forkoff = roundup(sizeof(uuid_t), 8) >> 3;
                break;
        case XFS_DINODE_FMT_LOCAL:
        case XFS_DINODE_FMT_EXTENTS:
        case XFS_DINODE_FMT_BTREE:
                ip->i_d.di_forkoff = xfs_attr_shortform_bytesfit(ip, size);
                if (!ip->i_d.di_forkoff)
                        ip->i_d.di_forkoff = xfs_default_attroffset(ip) >> 3;
                else if (mp->m_flags & XFS_MOUNT_ATTR2)
                        version = 2;
                break;
        default:
                ASSERT(0);
                error = XFS_ERROR(EINVAL);
                goto error1;
        }

        ASSERT(ip->i_afp == NULL);
        ip->i_afp = kmem_zone_zalloc(xfs_ifork_zone, KM_SLEEP);
        ip->i_afp->if_flags = XFS_IFEXTENTS;
        logflags = 0;
        xfs_bmap_init(&flist, &firstblock);
        switch (ip->i_d.di_format) {
        case XFS_DINODE_FMT_LOCAL:
                error = xfs_bmap_add_attrfork_local(tp, ip, &firstblock, &flist,
                        &logflags);
                break;
        case XFS_DINODE_FMT_EXTENTS:
                error = xfs_bmap_add_attrfork_extents(tp, ip, &firstblock,
                        &flist, &logflags);
                break;
        case XFS_DINODE_FMT_BTREE:
                error = xfs_bmap_add_attrfork_btree(tp, ip, &firstblock, &flist,
                        &logflags);
                break;
        default:
                error = 0;
                break;
        }
        if (logflags)
                xfs_trans_log_inode(tp, ip, logflags);
        if (error)
                goto error2;
        if (!xfs_sb_version_hasattr(&mp->m_sb) ||
           (!xfs_sb_version_hasattr2(&mp->m_sb) && version == 2)) {
                __int64_t sbfields = 0;

                spin_lock(&mp->m_sb_lock);
                if (!xfs_sb_version_hasattr(&mp->m_sb)) {
                        xfs_sb_version_addattr(&mp->m_sb);
                        sbfields |= XFS_SB_VERSIONNUM;
                }
                if (!xfs_sb_version_hasattr2(&mp->m_sb) && version == 2) {
                        xfs_sb_version_addattr2(&mp->m_sb);
                        sbfields |= (XFS_SB_VERSIONNUM | XFS_SB_FEATURES2);
                }
                if (sbfields) {
                        spin_unlock(&mp->m_sb_lock);
                        xfs_mod_sb(tp, sbfields);
                } else
                        spin_unlock(&mp->m_sb_lock);
        }

        error = xfs_bmap_finish(&tp, &flist, &committed);
        if (error)
                goto error2;
        return xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
error2:
        xfs_bmap_cancel(&flist);
error1:
        xfs_iunlock(ip, XFS_ILOCK_EXCL);
error0:
        xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
        return error;
}

/*
 * Internal and external extent tree search functions.
 */

/*
 * Read in the extents to if_extents.
 * All inode fields are set up by caller, we just traverse the btree
 * and copy the records in. If the file system cannot contain unwritten
 * extents, the records are checked for no "state" flags.
 */
int                                     /* error */
xfs_bmap_read_extents(
        xfs_trans_t             *tp,    /* transaction pointer */
        xfs_inode_t             *ip,    /* incore inode */
        int                     whichfork) /* data or attr fork */
{
        struct xfs_btree_block  *block; /* current btree block */
        xfs_fsblock_t           bno;    /* block # of "block" */
        xfs_buf_t               *bp;    /* buffer for "block" */
        int                     error;  /* error return value */
        xfs_exntfmt_t           exntf;  /* XFS_EXTFMT_NOSTATE, if checking */
        xfs_extnum_t            i, j;   /* index into the extents list */
        xfs_ifork_t             *ifp;   /* fork structure */
        int                     level;  /* btree level, for checking */
        xfs_mount_t             *mp;    /* file system mount structure */
        __be64                  *pp;    /* pointer to block address */
        /* REFERENCED */
        xfs_extnum_t            room;   /* number of entries there's room for */

        bno = NULLFSBLOCK;
        mp = ip->i_mount;
        ifp = XFS_IFORK_PTR(ip, whichfork);
        exntf = (whichfork != XFS_DATA_FORK) ? XFS_EXTFMT_NOSTATE :
                                        XFS_EXTFMT_INODE(ip);
        block = ifp->if_broot;
        /*
         * Root level must use BMAP_BROOT_PTR_ADDR macro to get ptr out.
         */
        level = be16_to_cpu(block->bb_level);
        ASSERT(level > 0);
        pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes);
        bno = be64_to_cpu(*pp);
        ASSERT(bno != NULLDFSBNO);
        ASSERT(XFS_FSB_TO_AGNO(mp, bno) < mp->m_sb.sb_agcount);
        ASSERT(XFS_FSB_TO_AGBNO(mp, bno) < mp->m_sb.sb_agblocks);
        /*
         * Go down the tree until leaf level is reached, following the first
         * pointer (leftmost) at each level.
         */
        while (level-- > 0) {
                error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp,
                                XFS_BMAP_BTREE_REF, &xfs_bmbt_buf_ops);
                if (error)
                        return error;
                block = XFS_BUF_TO_BLOCK(bp);
                XFS_WANT_CORRUPTED_GOTO(
                        xfs_bmap_sanity_check(mp, bp, level),
                        error0);
                if (level == 0)
                        break;
                pp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]);
                bno = be64_to_cpu(*pp);
                XFS_WANT_CORRUPTED_GOTO(XFS_FSB_SANITY_CHECK(mp, bno), error0);
                xfs_trans_brelse(tp, bp);
        }
        /*
         * Here with bp and block set to the leftmost leaf node in the tree.
         */
        room = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
        i = 0;
        /*
         * Loop over all leaf nodes.  Copy information to the extent records.
         */
        for (;;) {
                xfs_bmbt_rec_t  *frp;
                xfs_fsblock_t   nextbno;
                xfs_extnum_t    num_recs;
                xfs_extnum_t    start;

                num_recs = xfs_btree_get_numrecs(block);
                if (unlikely(i + num_recs > room)) {
                        ASSERT(i + num_recs <= room);
                        xfs_warn(ip->i_mount,
                                "corrupt dinode %Lu, (btree extents).",
                                (unsigned long long) ip->i_ino);
                        XFS_CORRUPTION_ERROR("xfs_bmap_read_extents(1)",
                                XFS_ERRLEVEL_LOW, ip->i_mount, block);
                        goto error0;
                }
                XFS_WANT_CORRUPTED_GOTO(
                        xfs_bmap_sanity_check(mp, bp, 0),
                        error0);
                /*
                 * Read-ahead the next leaf block, if any.
                 */
                nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
                if (nextbno != NULLFSBLOCK)
                        xfs_btree_reada_bufl(mp, nextbno, 1,
                                             &xfs_bmbt_buf_ops);
                /*
                 * Copy records into the extent records.
                 */
                frp = XFS_BMBT_REC_ADDR(mp, block, 1);
                start = i;
                for (j = 0; j < num_recs; j++, i++, frp++) {
                        xfs_bmbt_rec_host_t *trp = xfs_iext_get_ext(ifp, i);
                        trp->l0 = be64_to_cpu(frp->l0);
                        trp->l1 = be64_to_cpu(frp->l1);
                }
                if (exntf == XFS_EXTFMT_NOSTATE) {
                        /*
                         * Check all attribute bmap btree records and
                         * any "older" data bmap btree records for a
                         * set bit in the "extent flag" position.
                         */
                        if (unlikely(xfs_check_nostate_extents(ifp,
                                        start, num_recs))) {
                                XFS_ERROR_REPORT("xfs_bmap_read_extents(2)",
                                                 XFS_ERRLEVEL_LOW,
                                                 ip->i_mount);
                                goto error0;
                        }
                }
                xfs_trans_brelse(tp, bp);
                bno = nextbno;
                /*
                 * If we've reached the end, stop.
                 */
                if (bno == NULLFSBLOCK)
                        break;
                error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp,
                                XFS_BMAP_BTREE_REF, &xfs_bmbt_buf_ops);
                if (error)
                        return error;
                block = XFS_BUF_TO_BLOCK(bp);
        }
        ASSERT(i == (ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t)));
        ASSERT(i == XFS_IFORK_NEXTENTS(ip, whichfork));
        XFS_BMAP_TRACE_EXLIST(ip, i, whichfork);
        return 0;
error0:
        xfs_trans_brelse(tp, bp);
        return XFS_ERROR(EFSCORRUPTED);
}


/*
 * Search the extent records for the entry containing block bno.
 * If bno lies in a hole, point to the next entry.  If bno lies
 * past eof, *eofp will be set, and *prevp will contain the last
 * entry (null if none).  Else, *lastxp will be set to the index
 * of the found entry; *gotp will contain the entry.
 */
STATIC xfs_bmbt_rec_host_t *            /* pointer to found extent entry */
xfs_bmap_search_multi_extents(
        xfs_ifork_t     *ifp,           /* inode fork pointer */
        xfs_fileoff_t   bno,            /* block number searched for */
        int             *eofp,          /* out: end of file found */
        xfs_extnum_t    *lastxp,        /* out: last extent index */
        xfs_bmbt_irec_t *gotp,          /* out: extent entry found */
        xfs_bmbt_irec_t *prevp)         /* out: previous extent entry found */
{
        xfs_bmbt_rec_host_t *ep;                /* extent record pointer */
        xfs_extnum_t    lastx;          /* last extent index */

        /*
         * Initialize the extent entry structure to catch access to
         * uninitialized br_startblock field.
         */
        gotp->br_startoff = 0xffa5a5a5a5a5a5a5LL;
        gotp->br_blockcount = 0xa55a5a5a5a5a5a5aLL;
        gotp->br_state = XFS_EXT_INVALID;
#if XFS_BIG_BLKNOS
        gotp->br_startblock = 0xffffa5a5a5a5a5a5LL;
#else
        gotp->br_startblock = 0xffffa5a5;
#endif
        prevp->br_startoff = NULLFILEOFF;

        ep = xfs_iext_bno_to_ext(ifp, bno, &lastx);
        if (lastx > 0) {
                xfs_bmbt_get_all(xfs_iext_get_ext(ifp, lastx - 1), prevp);
        }
        if (lastx < (ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t))) {
                xfs_bmbt_get_all(ep, gotp);
                *eofp = 0;
        } else {
                if (lastx > 0) {
                        *gotp = *prevp;
                }
                *eofp = 1;
                ep = NULL;
        }
        *lastxp = lastx;
        return ep;
}

/*
 * Search the extents list for the inode, for the extent containing bno.
 * If bno lies in a hole, point to the next entry.  If bno lies past eof,
 * *eofp will be set, and *prevp will contain the last entry (null if none).
 * Else, *lastxp will be set to the index of the found
 * entry; *gotp will contain the entry.
 */
STATIC xfs_bmbt_rec_host_t *                 /* pointer to found extent entry */
xfs_bmap_search_extents(
        xfs_inode_t     *ip,            /* incore inode pointer */
        xfs_fileoff_t   bno,            /* block number searched for */
        int             fork,           /* data or attr fork */
        int             *eofp,          /* out: end of file found */
        xfs_extnum_t    *lastxp,        /* out: last extent index */
        xfs_bmbt_irec_t *gotp,          /* out: extent entry found */
        xfs_bmbt_irec_t *prevp)         /* out: previous extent entry found */
{
        xfs_ifork_t     *ifp;           /* inode fork pointer */
        xfs_bmbt_rec_host_t  *ep;            /* extent record pointer */

        XFS_STATS_INC(xs_look_exlist);
        ifp = XFS_IFORK_PTR(ip, fork);

        ep = xfs_bmap_search_multi_extents(ifp, bno, eofp, lastxp, gotp, prevp);

        if (unlikely(!(gotp->br_startblock) && (*lastxp != NULLEXTNUM) &&
                     !(XFS_IS_REALTIME_INODE(ip) && fork == XFS_DATA_FORK))) {
                xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
                                "Access to block zero in inode %llu "
                                "start_block: %llx start_off: %llx "
                                "blkcnt: %llx extent-state: %x lastx: %x\n",
                        (unsigned long long)ip->i_ino,
                        (unsigned long long)gotp->br_startblock,
                        (unsigned long long)gotp->br_startoff,
                        (unsigned long long)gotp->br_blockcount,
                        gotp->br_state, *lastxp);
                *lastxp = NULLEXTNUM;
                *eofp = 1;
                return NULL;
        }
        return ep;
}

/*
 * Returns the file-relative block number of the first unused block(s)
 * in the file with at least "len" logically contiguous blocks free.
 * This is the lowest-address hole if the file has holes, else the first block
 * past the end of file.
 * Return 0 if the file is currently local (in-inode).
 */
int                                             /* error */
xfs_bmap_first_unused(
        xfs_trans_t     *tp,                    /* transaction pointer */
        xfs_inode_t     *ip,                    /* incore inode */
        xfs_extlen_t    len,                    /* size of hole to find */
        xfs_fileoff_t   *first_unused,          /* unused block */
        int             whichfork)              /* data or attr fork */
{
        int             error;                  /* error return value */
        int             idx;                    /* extent record index */
        xfs_ifork_t     *ifp;                   /* inode fork pointer */
        xfs_fileoff_t   lastaddr;               /* last block number seen */
        xfs_fileoff_t   lowest;                 /* lowest useful block */
        xfs_fileoff_t   max;                    /* starting useful block */
        xfs_fileoff_t   off;                    /* offset for this block */
        xfs_extnum_t    nextents;               /* number of extent entries */

        ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE ||
               XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS ||
               XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL);
        if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
                *first_unused = 0;
                return 0;
        }
        ifp = XFS_IFORK_PTR(ip, whichfork);
        if (!(ifp->if_flags & XFS_IFEXTENTS) &&
            (error = xfs_iread_extents(tp, ip, whichfork)))
                return error;
        lowest = *first_unused;
        nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
        for (idx = 0, lastaddr = 0, max = lowest; idx < nextents; idx++) {
                xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, idx);
                off = xfs_bmbt_get_startoff(ep);
                /*
                 * See if the hole before this extent will work.
                 */
                if (off >= lowest + len && off - max >= len) {
                        *first_unused = max;
                        return 0;
                }
                lastaddr = off + xfs_bmbt_get_blockcount(ep);
                max = XFS_FILEOFF_MAX(lastaddr, lowest);
        }
        *first_unused = max;
        return 0;
}

/*
 * Returns the file-relative block number of the last block + 1 before
 * last_block (input value) in the file.
 * This is not based on i_size, it is based on the extent records.
 * Returns 0 for local files, as they do not have extent records.
 */
int                                             /* error */
xfs_bmap_last_before(
        xfs_trans_t     *tp,                    /* transaction pointer */
        xfs_inode_t     *ip,                    /* incore inode */
        xfs_fileoff_t   *last_block,            /* last block */
        int             whichfork)              /* data or attr fork */
{
        xfs_fileoff_t   bno;                    /* input file offset */
        int             eof;                    /* hit end of file */
        xfs_bmbt_rec_host_t *ep;                /* pointer to last extent */
        int             error;                  /* error return value */
        xfs_bmbt_irec_t got;                    /* current extent value */
        xfs_ifork_t     *ifp;                   /* inode fork pointer */
        xfs_extnum_t    lastx;                  /* last extent used */
        xfs_bmbt_irec_t prev;                   /* previous extent value */

        if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE &&
            XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&
            XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_LOCAL)
               return XFS_ERROR(EIO);
        if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
                *last_block = 0;
                return 0;
        }
        ifp = XFS_IFORK_PTR(ip, whichfork);
        if (!(ifp->if_flags & XFS_IFEXTENTS) &&
            (error = xfs_iread_extents(tp, ip, whichfork)))
                return error;
        bno = *last_block - 1;
        ep = xfs_bmap_search_extents(ip, bno, whichfork, &eof, &lastx, &got,
                &prev);
        if (eof || xfs_bmbt_get_startoff(ep) > bno) {
                if (prev.br_startoff == NULLFILEOFF)
                        *last_block = 0;
                else
                        *last_block = prev.br_startoff + prev.br_blockcount;
        }
        /*
         * Otherwise *last_block is already the right answer.
         */
        return 0;
}

STATIC int
xfs_bmap_last_extent(
        struct xfs_trans        *tp,
        struct xfs_inode        *ip,
        int                     whichfork,
        struct xfs_bmbt_irec    *rec,
        int                     *is_empty)
{
        struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
        int                     error;
        int                     nextents;

        if (!(ifp->if_flags & XFS_IFEXTENTS)) {
                error = xfs_iread_extents(tp, ip, whichfork);
                if (error)
                        return error;
        }

        nextents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
        if (nextents == 0) {
                *is_empty = 1;
                return 0;
        }

        xfs_bmbt_get_all(xfs_iext_get_ext(ifp, nextents - 1), rec);
        *is_empty = 0;
        return 0;
}

/*
 * Check the last inode extent to determine whether this allocation will result
 * in blocks being allocated at the end of the file. When we allocate new data
 * blocks at the end of the file which do not start at the previous data block,
 * we will try to align the new blocks at stripe unit boundaries.
 *
 * Returns 0 in bma->aeof if the file (fork) is empty as any new write will be
 * at, or past the EOF.
 */
STATIC int
xfs_bmap_isaeof(
        struct xfs_bmalloca     *bma,
        int                     whichfork)
{
        struct xfs_bmbt_irec    rec;
        int                     is_empty;
        int                     error;

        bma->aeof = 0;
        error = xfs_bmap_last_extent(NULL, bma->ip, whichfork, &rec,
                                     &is_empty);
        if (error || is_empty)
                return error;

        /*
         * Check if we are allocation or past the last extent, or at least into
         * the last delayed allocated extent.
         */
        bma->aeof = bma->offset >= rec.br_startoff + rec.br_blockcount ||
                (bma->offset >= rec.br_startoff &&
                 isnullstartblock(rec.br_startblock));
        return 0;
}

/*
 * Check if the endoff is outside the last extent. If so the caller will grow
 * the allocation to a stripe unit boundary.  All offsets are considered outside
 * the end of file for an empty fork, so 1 is returned in *eof in that case.
 */
int
xfs_bmap_eof(
        struct xfs_inode        *ip,
        xfs_fileoff_t           endoff,
        int                     whichfork,
        int                     *eof)
{
        struct xfs_bmbt_irec    rec;
        int                     error;

        error = xfs_bmap_last_extent(NULL, ip, whichfork, &rec, eof);
        if (error || *eof)
                return error;

        *eof = endoff >= rec.br_startoff + rec.br_blockcount;
        return 0;
}

/*
 * Returns the file-relative block number of the first block past eof in
 * the file.  This is not based on i_size, it is based on the extent records.
 * Returns 0 for local files, as they do not have extent records.
 */
int
xfs_bmap_last_offset(
        struct xfs_trans        *tp,
        struct xfs_inode        *ip,
        xfs_fileoff_t           *last_block,
        int                     whichfork)
{
        struct xfs_bmbt_irec    rec;
        int                     is_empty;
        int                     error;

        *last_block = 0;

        if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL)
                return 0;

        if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE &&
            XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS)
               return XFS_ERROR(EIO);

        error = xfs_bmap_last_extent(NULL, ip, whichfork, &rec, &is_empty);
        if (error || is_empty)
                return error;

        *last_block = rec.br_startoff + rec.br_blockcount;
        return 0;
}

/*
 * Returns whether the selected fork of the inode has exactly one
 * block or not.  For the data fork we check this matches di_size,
 * implying the file's range is 0..bsize-1.
 */
int                                     /* 1=>1 block, 0=>otherwise */
xfs_bmap_one_block(
        xfs_inode_t     *ip,            /* incore inode */
        int             whichfork)      /* data or attr fork */
{
        xfs_bmbt_rec_host_t *ep;        /* ptr to fork's extent */
        xfs_ifork_t     *ifp;           /* inode fork pointer */
        int             rval;           /* return value */
        xfs_bmbt_irec_t s;              /* internal version of extent */

#ifndef DEBUG

        if (whichfork == XFS_DATA_FORK)
                return XFS_ISIZE(ip) == ip->i_mount->m_sb.sb_blocksize;
#endif  /* !DEBUG */
        if (XFS_IFORK_NEXTENTS(ip, whichfork) != 1)
                return 0;
        if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS)
                return 0;
        ifp = XFS_IFORK_PTR(ip, whichfork);
        ASSERT(ifp->if_flags & XFS_IFEXTENTS);
        ep = xfs_iext_get_ext(ifp, 0);
        xfs_bmbt_get_all(ep, &s);
        rval = s.br_startoff == 0 && s.br_blockcount == 1;
        if (rval && whichfork == XFS_DATA_FORK)
                ASSERT(XFS_ISIZE(ip) == ip->i_mount->m_sb.sb_blocksize);
        return rval;
}

/*
 * Extent tree manipulation functions used during allocation.
 */

/*
 * Convert a delayed allocation to a real allocation.
 */
STATIC int                              /* error */
xfs_bmap_add_extent_delay_real(
        struct xfs_bmalloca     *bma)
{
        struct xfs_bmbt_irec    *new = &bma->got;
        int                     diff;   /* temp value */
        xfs_bmbt_rec_host_t     *ep;    /* extent entry for idx */
        int                     error;  /* error return value */
        int                     i;      /* temp state */
        xfs_ifork_t             *ifp;   /* inode fork pointer */
        xfs_fileoff_t           new_endoff;     /* end offset of new entry */
        xfs_bmbt_irec_t         r[3];   /* neighbor extent entries */
                                        /* left is 0, right is 1, prev is 2 */
        int                     rval=0; /* return value (logging flags) */
        int                     state = 0;/* state bits, accessed thru macros */
        xfs_filblks_t           da_new; /* new count del alloc blocks used */
        xfs_filblks_t           da_old; /* old count del alloc blocks used */
        xfs_filblks_t           temp=0; /* value for da_new calculations */
        xfs_filblks_t           temp2=0;/* value for da_new calculations */
        int                     tmp_rval;       /* partial logging flags */

        ifp = XFS_IFORK_PTR(bma->ip, XFS_DATA_FORK);

        ASSERT(bma->idx >= 0);
        ASSERT(bma->idx <= ifp->if_bytes / sizeof(struct xfs_bmbt_rec));
        ASSERT(!isnullstartblock(new->br_startblock));
        ASSERT(!bma->cur ||
               (bma->cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL));

        XFS_STATS_INC(xs_add_exlist);

#define LEFT            r[0]
#define RIGHT           r[1]
#define PREV            r[2]

        /*
         * Set up a bunch of variables to make the tests simpler.
         */
        ep = xfs_iext_get_ext(ifp, bma->idx);
        xfs_bmbt_get_all(ep, &PREV);
        new_endoff = new->br_startoff + new->br_blockcount;
        ASSERT(PREV.br_startoff <= new->br_startoff);
        ASSERT(PREV.br_startoff + PREV.br_blockcount >= new_endoff);

        da_old = startblockval(PREV.br_startblock);
        da_new = 0;

        /*
         * Set flags determining what part of the previous delayed allocation
         * extent is being replaced by a real allocation.
         */
        if (PREV.br_startoff == new->br_startoff)
                state |= BMAP_LEFT_FILLING;
        if (PREV.br_startoff + PREV.br_blockcount == new_endoff)
                state |= BMAP_RIGHT_FILLING;

        /*
         * Check and set flags if this segment has a left neighbor.
         * Don't set contiguous if the combined extent would be too large.
         */
        if (bma->idx > 0) {
                state |= BMAP_LEFT_VALID;
                xfs_bmbt_get_all(xfs_iext_get_ext(ifp, bma->idx - 1), &LEFT);

                if (isnullstartblock(LEFT.br_startblock))
                        state |= BMAP_LEFT_DELAY;
        }

        if ((state & BMAP_LEFT_VALID) && !(state & BMAP_LEFT_DELAY) &&
            LEFT.br_startoff + LEFT.br_blockcount == new->br_startoff &&
            LEFT.br_startblock + LEFT.br_blockcount == new->br_startblock &&
            LEFT.br_state == new->br_state &&
            LEFT.br_blockcount + new->br_blockcount <= MAXEXTLEN)
                state |= BMAP_LEFT_CONTIG;

        /*
         * Check and set flags if this segment has a right neighbor.
         * Don't set contiguous if the combined extent would be too large.
         * Also check for all-three-contiguous being too large.
         */
        if (bma->idx < bma->ip->i_df.if_bytes / (uint)sizeof(xfs_bmbt_rec_t) - 1) {
                state |= BMAP_RIGHT_VALID;
                xfs_bmbt_get_all(xfs_iext_get_ext(ifp, bma->idx + 1), &RIGHT);

                if (isnullstartblock(RIGHT.br_startblock))
                        state |= BMAP_RIGHT_DELAY;
        }

        if ((state & BMAP_RIGHT_VALID) && !(state & BMAP_RIGHT_DELAY) &&
            new_endoff == RIGHT.br_startoff &&
            new->br_startblock + new->br_blockcount == RIGHT.br_startblock &&
            new->br_state == RIGHT.br_state &&
            new->br_blockcount + RIGHT.br_blockcount <= MAXEXTLEN &&
            ((state & (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
                       BMAP_RIGHT_FILLING)) !=
                      (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
                       BMAP_RIGHT_FILLING) ||
             LEFT.br_blockcount + new->br_blockcount + RIGHT.br_blockcount
                        <= MAXEXTLEN))
                state |= BMAP_RIGHT_CONTIG;

        error = 0;
        /*
         * Switch out based on the FILLING and CONTIG state bits.
         */
        switch (state & (BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG |
                         BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG)) {
        case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG |
             BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
                /*
                 * Filling in all of a previously delayed allocation extent.
                 * The left and right neighbors are both contiguous with new.
                 */
                bma->idx--;
                trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, bma->idx),
                        LEFT.br_blockcount + PREV.br_blockcount +
                        RIGHT.br_blockcount);
                trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);

                xfs_iext_remove(bma->ip, bma->idx + 1, 2, state);
                bma->ip->i_d.di_nextents--;
                if (bma->cur == NULL)
                        rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
                else {
                        rval = XFS_ILOG_CORE;
                        error = xfs_bmbt_lookup_eq(bma->cur, RIGHT.br_startoff,
                                        RIGHT.br_startblock,
                                        RIGHT.br_blockcount, &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        error = xfs_btree_delete(bma->cur, &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        error = xfs_btree_decrement(bma->cur, 0, &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        error = xfs_bmbt_update(bma->cur, LEFT.br_startoff,
                                        LEFT.br_startblock,
                                        LEFT.br_blockcount +
                                        PREV.br_blockcount +
                                        RIGHT.br_blockcount, LEFT.br_state);
                        if (error)
                                goto done;
                }
                break;

        case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG:
                /*
                 * Filling in all of a previously delayed allocation extent.
                 * The left neighbor is contiguous, the right is not.
                 */
                bma->idx--;

                trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, bma->idx),
                        LEFT.br_blockcount + PREV.br_blockcount);
                trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);

                xfs_iext_remove(bma->ip, bma->idx + 1, 1, state);
                if (bma->cur == NULL)
                        rval = XFS_ILOG_DEXT;
                else {
                        rval = 0;
                        error = xfs_bmbt_lookup_eq(bma->cur, LEFT.br_startoff,
                                        LEFT.br_startblock, LEFT.br_blockcount,
                                        &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        error = xfs_bmbt_update(bma->cur, LEFT.br_startoff,
                                        LEFT.br_startblock,
                                        LEFT.br_blockcount +
                                        PREV.br_blockcount, LEFT.br_state);
                        if (error)
                                goto done;
                }
                break;

        case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
                /*
                 * Filling in all of a previously delayed allocation extent.
                 * The right neighbor is contiguous, the left is not.
                 */
                trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
                xfs_bmbt_set_startblock(ep, new->br_startblock);
                xfs_bmbt_set_blockcount(ep,
                        PREV.br_blockcount + RIGHT.br_blockcount);
                trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);

                xfs_iext_remove(bma->ip, bma->idx + 1, 1, state);
                if (bma->cur == NULL)
                        rval = XFS_ILOG_DEXT;
                else {
                        rval = 0;
                        error = xfs_bmbt_lookup_eq(bma->cur, RIGHT.br_startoff,
                                        RIGHT.br_startblock,
                                        RIGHT.br_blockcount, &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        error = xfs_bmbt_update(bma->cur, PREV.br_startoff,
                                        new->br_startblock,
                                        PREV.br_blockcount +
                                        RIGHT.br_blockcount, PREV.br_state);
                        if (error)
                                goto done;
                }
                break;

        case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING:
                /*
                 * Filling in all of a previously delayed allocation extent.
                 * Neither the left nor right neighbors are contiguous with
                 * the new one.
                 */
                trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
                xfs_bmbt_set_startblock(ep, new->br_startblock);
                trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);

                bma->ip->i_d.di_nextents++;
                if (bma->cur == NULL)
                        rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
                else {
                        rval = XFS_ILOG_CORE;
                        error = xfs_bmbt_lookup_eq(bma->cur, new->br_startoff,
                                        new->br_startblock, new->br_blockcount,
                                        &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 0, done);
                        bma->cur->bc_rec.b.br_state = XFS_EXT_NORM;
                        error = xfs_btree_insert(bma->cur, &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                }
                break;

        case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG:
                /*
                 * Filling in the first part of a previous delayed allocation.
                 * The left neighbor is contiguous.
                 */
                trace_xfs_bmap_pre_update(bma->ip, bma->idx - 1, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, bma->idx - 1),
                        LEFT.br_blockcount + new->br_blockcount);
                xfs_bmbt_set_startoff(ep,
                        PREV.br_startoff + new->br_blockcount);
                trace_xfs_bmap_post_update(bma->ip, bma->idx - 1, state, _THIS_IP_);

                temp = PREV.br_blockcount - new->br_blockcount;
                trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(ep, temp);
                if (bma->cur == NULL)
                        rval = XFS_ILOG_DEXT;
                else {
                        rval = 0;
                        error = xfs_bmbt_lookup_eq(bma->cur, LEFT.br_startoff,
                                        LEFT.br_startblock, LEFT.br_blockcount,
                                        &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        error = xfs_bmbt_update(bma->cur, LEFT.br_startoff,
                                        LEFT.br_startblock,
                                        LEFT.br_blockcount +
                                        new->br_blockcount,
                                        LEFT.br_state);
                        if (error)
                                goto done;
                }
                da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(bma->ip, temp),
                        startblockval(PREV.br_startblock));
                xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
                trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);

                bma->idx--;
                break;

        case BMAP_LEFT_FILLING:
                /*
                 * Filling in the first part of a previous delayed allocation.
                 * The left neighbor is not contiguous.
                 */
                trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
                xfs_bmbt_set_startoff(ep, new_endoff);
                temp = PREV.br_blockcount - new->br_blockcount;
                xfs_bmbt_set_blockcount(ep, temp);
                xfs_iext_insert(bma->ip, bma->idx, 1, new, state);
                bma->ip->i_d.di_nextents++;
                if (bma->cur == NULL)
                        rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
                else {
                        rval = XFS_ILOG_CORE;
                        error = xfs_bmbt_lookup_eq(bma->cur, new->br_startoff,
                                        new->br_startblock, new->br_blockcount,
                                        &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 0, done);
                        bma->cur->bc_rec.b.br_state = XFS_EXT_NORM;
                        error = xfs_btree_insert(bma->cur, &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                }

                if (xfs_bmap_needs_btree(bma->ip, XFS_DATA_FORK)) {
                        error = xfs_bmap_extents_to_btree(bma->tp, bma->ip,
                                        bma->firstblock, bma->flist,
                                        &bma->cur, 1, &tmp_rval, XFS_DATA_FORK);
                        rval |= tmp_rval;
                        if (error)
                                goto done;
                }
                da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(bma->ip, temp),
                        startblockval(PREV.br_startblock) -
                        (bma->cur ? bma->cur->bc_private.b.allocated : 0));
                ep = xfs_iext_get_ext(ifp, bma->idx + 1);
                xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
                trace_xfs_bmap_post_update(bma->ip, bma->idx + 1, state, _THIS_IP_);
                break;

        case BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
                /*
                 * Filling in the last part of a previous delayed allocation.
                 * The right neighbor is contiguous with the new allocation.
                 */
                temp = PREV.br_blockcount - new->br_blockcount;
                trace_xfs_bmap_pre_update(bma->ip, bma->idx + 1, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(ep, temp);
                xfs_bmbt_set_allf(xfs_iext_get_ext(ifp, bma->idx + 1),
                        new->br_startoff, new->br_startblock,
                        new->br_blockcount + RIGHT.br_blockcount,
                        RIGHT.br_state);
                trace_xfs_bmap_post_update(bma->ip, bma->idx + 1, state, _THIS_IP_);
                if (bma->cur == NULL)
                        rval = XFS_ILOG_DEXT;
                else {
                        rval = 0;
                        error = xfs_bmbt_lookup_eq(bma->cur, RIGHT.br_startoff,
                                        RIGHT.br_startblock,
                                        RIGHT.br_blockcount, &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        error = xfs_bmbt_update(bma->cur, new->br_startoff,
                                        new->br_startblock,
                                        new->br_blockcount +
                                        RIGHT.br_blockcount,
                                        RIGHT.br_state);
                        if (error)
                                goto done;
                }

                da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(bma->ip, temp),
                        startblockval(PREV.br_startblock));
                trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
                xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
                trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);

                bma->idx++;
                break;

        case BMAP_RIGHT_FILLING:
                /*
                 * Filling in the last part of a previous delayed allocation.
                 * The right neighbor is not contiguous.
                 */
                temp = PREV.br_blockcount - new->br_blockcount;
                trace_xfs_bmap_pre_update(bma->ip, bma->idx, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(ep, temp);
                xfs_iext_insert(bma->ip, bma->idx + 1, 1, new, state);
                bma->ip->i_d.di_nextents++;
                if (bma->cur == NULL)
                        rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
                else {
                        rval = XFS_ILOG_CORE;
                        error = xfs_bmbt_lookup_eq(bma->cur, new->br_startoff,
                                        new->br_startblock, new->br_blockcount,
                                        &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 0, done);
                        bma->cur->bc_rec.b.br_state = XFS_EXT_NORM;
                        error = xfs_btree_insert(bma->cur, &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                }

                if (xfs_bmap_needs_btree(bma->ip, XFS_DATA_FORK)) {
                        error = xfs_bmap_extents_to_btree(bma->tp, bma->ip,
                                bma->firstblock, bma->flist, &bma->cur, 1,
                                &tmp_rval, XFS_DATA_FORK);
                        rval |= tmp_rval;
                        if (error)
                                goto done;
                }
                da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(bma->ip, temp),
                        startblockval(PREV.br_startblock) -
                        (bma->cur ? bma->cur->bc_private.b.allocated : 0));
                ep = xfs_iext_get_ext(ifp, bma->idx);
                xfs_bmbt_set_startblock(ep, nullstartblock(da_new));
                trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);

                bma->idx++;
                break;

        case 0:
                /*
                 * Filling in the middle part of a previous delayed allocation.
                 * Contiguity is impossible here.
                 * This case is avoided almost all the time.
                 *
                 * We start with a delayed allocation:
                 *
                 * +ddddddddddddddddddddddddddddddddddddddddddddddddddddddd+
                 *  PREV @ idx
                 *
                 * and we are allocating:
                 *                     +rrrrrrrrrrrrrrrrr+
                 *                            new
                 *
                 * and we set it up for insertion as:
                 * +ddddddddddddddddddd+rrrrrrrrrrrrrrrrr+ddddddddddddddddd+
                 *                            new
                 *  PREV @ idx          LEFT              RIGHT
                 *                      inserted at idx + 1
                 */
                temp = new->br_startoff - PREV.br_startoff;
                temp2 = PREV.br_startoff + PREV.br_blockcount - new_endoff;
                trace_xfs_bmap_pre_update(bma->ip, bma->idx, 0, _THIS_IP_);
                xfs_bmbt_set_blockcount(ep, temp);      /* truncate PREV */
                LEFT = *new;
                RIGHT.br_state = PREV.br_state;
                RIGHT.br_startblock = nullstartblock(
                                (int)xfs_bmap_worst_indlen(bma->ip, temp2));
                RIGHT.br_startoff = new_endoff;
                RIGHT.br_blockcount = temp2;
                /* insert LEFT (r[0]) and RIGHT (r[1]) at the same time */
                xfs_iext_insert(bma->ip, bma->idx + 1, 2, &LEFT, state);
                bma->ip->i_d.di_nextents++;
                if (bma->cur == NULL)
                        rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
                else {
                        rval = XFS_ILOG_CORE;
                        error = xfs_bmbt_lookup_eq(bma->cur, new->br_startoff,
                                        new->br_startblock, new->br_blockcount,
                                        &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 0, done);
                        bma->cur->bc_rec.b.br_state = XFS_EXT_NORM;
                        error = xfs_btree_insert(bma->cur, &i);
                        if (error)
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                }

                if (xfs_bmap_needs_btree(bma->ip, XFS_DATA_FORK)) {
                        error = xfs_bmap_extents_to_btree(bma->tp, bma->ip,
                                        bma->firstblock, bma->flist, &bma->cur,
                                        1, &tmp_rval, XFS_DATA_FORK);
                        rval |= tmp_rval;
                        if (error)
                                goto done;
                }
                temp = xfs_bmap_worst_indlen(bma->ip, temp);
                temp2 = xfs_bmap_worst_indlen(bma->ip, temp2);
                diff = (int)(temp + temp2 - startblockval(PREV.br_startblock) -
                        (bma->cur ? bma->cur->bc_private.b.allocated : 0));
                if (diff > 0) {
                        error = xfs_icsb_modify_counters(bma->ip->i_mount,
                                        XFS_SBS_FDBLOCKS,
                                        -((int64_t)diff), 0);
                        ASSERT(!error);
                        if (error)
                                goto done;
                }

                ep = xfs_iext_get_ext(ifp, bma->idx);
                xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
                trace_xfs_bmap_post_update(bma->ip, bma->idx, state, _THIS_IP_);
                trace_xfs_bmap_pre_update(bma->ip, bma->idx + 2, state, _THIS_IP_);
                xfs_bmbt_set_startblock(xfs_iext_get_ext(ifp, bma->idx + 2),
                        nullstartblock((int)temp2));
                trace_xfs_bmap_post_update(bma->ip, bma->idx + 2, state, _THIS_IP_);

                bma->idx++;
                da_new = temp + temp2;
                break;

        case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
        case BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
        case BMAP_LEFT_FILLING | BMAP_RIGHT_CONTIG:
        case BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG:
        case BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
        case BMAP_LEFT_CONTIG:
        case BMAP_RIGHT_CONTIG:
                /*
                 * These cases are all impossible.
                 */
                ASSERT(0);
        }

        /* convert to a btree if necessary */
        if (xfs_bmap_needs_btree(bma->ip, XFS_DATA_FORK)) {
                int     tmp_logflags;   /* partial log flag return val */

                ASSERT(bma->cur == NULL);
                error = xfs_bmap_extents_to_btree(bma->tp, bma->ip,
                                bma->firstblock, bma->flist, &bma->cur,
                                da_old > 0, &tmp_logflags, XFS_DATA_FORK);
                bma->logflags |= tmp_logflags;
                if (error)
                        goto done;
        }

        /* adjust for changes in reserved delayed indirect blocks */
        if (da_old || da_new) {
                temp = da_new;
                if (bma->cur)
                        temp += bma->cur->bc_private.b.allocated;
                ASSERT(temp <= da_old);
                if (temp < da_old)
                        xfs_icsb_modify_counters(bma->ip->i_mount,
                                        XFS_SBS_FDBLOCKS,
                                        (int64_t)(da_old - temp), 0);
        }

        /* clear out the allocated field, done with it now in any case. */
        if (bma->cur)
                bma->cur->bc_private.b.allocated = 0;

        xfs_bmap_check_leaf_extents(bma->cur, bma->ip, XFS_DATA_FORK);
done:
        bma->logflags |= rval;
        return error;
#undef  LEFT
#undef  RIGHT
#undef  PREV
}

/*
 * Convert an unwritten allocation to a real allocation or vice versa.
 */
STATIC int                              /* error */
xfs_bmap_add_extent_unwritten_real(
        struct xfs_trans        *tp,
        xfs_inode_t             *ip,    /* incore inode pointer */
        xfs_extnum_t            *idx,   /* extent number to update/insert */
        xfs_btree_cur_t         **curp, /* if *curp is null, not a btree */
        xfs_bmbt_irec_t         *new,   /* new data to add to file extents */
        xfs_fsblock_t           *first, /* pointer to firstblock variable */
        xfs_bmap_free_t         *flist, /* list of extents to be freed */
        int                     *logflagsp) /* inode logging flags */
{
        xfs_btree_cur_t         *cur;   /* btree cursor */
        xfs_bmbt_rec_host_t     *ep;    /* extent entry for idx */
        int                     error;  /* error return value */
        int                     i;      /* temp state */
        xfs_ifork_t             *ifp;   /* inode fork pointer */
        xfs_fileoff_t           new_endoff;     /* end offset of new entry */
        xfs_exntst_t            newext; /* new extent state */
        xfs_exntst_t            oldext; /* old extent state */
        xfs_bmbt_irec_t         r[3];   /* neighbor extent entries */
                                        /* left is 0, right is 1, prev is 2 */
        int                     rval=0; /* return value (logging flags) */
        int                     state = 0;/* state bits, accessed thru macros */

        *logflagsp = 0;

        cur = *curp;
        ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);

        ASSERT(*idx >= 0);
        ASSERT(*idx <= ifp->if_bytes / sizeof(struct xfs_bmbt_rec));
        ASSERT(!isnullstartblock(new->br_startblock));

        XFS_STATS_INC(xs_add_exlist);

#define LEFT            r[0]
#define RIGHT           r[1]
#define PREV            r[2]

        /*
         * Set up a bunch of variables to make the tests simpler.
         */
        error = 0;
        ep = xfs_iext_get_ext(ifp, *idx);
        xfs_bmbt_get_all(ep, &PREV);
        newext = new->br_state;
        oldext = (newext == XFS_EXT_UNWRITTEN) ?
                XFS_EXT_NORM : XFS_EXT_UNWRITTEN;
        ASSERT(PREV.br_state == oldext);
        new_endoff = new->br_startoff + new->br_blockcount;
        ASSERT(PREV.br_startoff <= new->br_startoff);
        ASSERT(PREV.br_startoff + PREV.br_blockcount >= new_endoff);

        /*
         * Set flags determining what part of the previous oldext allocation
         * extent is being replaced by a newext allocation.
         */
        if (PREV.br_startoff == new->br_startoff)
                state |= BMAP_LEFT_FILLING;
        if (PREV.br_startoff + PREV.br_blockcount == new_endoff)
                state |= BMAP_RIGHT_FILLING;

        /*
         * Check and set flags if this segment has a left neighbor.
         * Don't set contiguous if the combined extent would be too large.
         */
        if (*idx > 0) {
                state |= BMAP_LEFT_VALID;
                xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx - 1), &LEFT);

                if (isnullstartblock(LEFT.br_startblock))
                        state |= BMAP_LEFT_DELAY;
        }

        if ((state & BMAP_LEFT_VALID) && !(state & BMAP_LEFT_DELAY) &&
            LEFT.br_startoff + LEFT.br_blockcount == new->br_startoff &&
            LEFT.br_startblock + LEFT.br_blockcount == new->br_startblock &&
            LEFT.br_state == newext &&
            LEFT.br_blockcount + new->br_blockcount <= MAXEXTLEN)
                state |= BMAP_LEFT_CONTIG;

        /*
         * Check and set flags if this segment has a right neighbor.
         * Don't set contiguous if the combined extent would be too large.
         * Also check for all-three-contiguous being too large.
         */
        if (*idx < ip->i_df.if_bytes / (uint)sizeof(xfs_bmbt_rec_t) - 1) {
                state |= BMAP_RIGHT_VALID;
                xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx + 1), &RIGHT);
                if (isnullstartblock(RIGHT.br_startblock))
                        state |= BMAP_RIGHT_DELAY;
        }

        if ((state & BMAP_RIGHT_VALID) && !(state & BMAP_RIGHT_DELAY) &&
            new_endoff == RIGHT.br_startoff &&
            new->br_startblock + new->br_blockcount == RIGHT.br_startblock &&
            newext == RIGHT.br_state &&
            new->br_blockcount + RIGHT.br_blockcount <= MAXEXTLEN &&
            ((state & (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
                       BMAP_RIGHT_FILLING)) !=
                      (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
                       BMAP_RIGHT_FILLING) ||
             LEFT.br_blockcount + new->br_blockcount + RIGHT.br_blockcount
                        <= MAXEXTLEN))
                state |= BMAP_RIGHT_CONTIG;

        /*
         * Switch out based on the FILLING and CONTIG state bits.
         */
        switch (state & (BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG |
                         BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG)) {
        case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG |
             BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
                /*
                 * Setting all of a previous oldext extent to newext.
                 * The left and right neighbors are both contiguous with new.
                 */
                --*idx;

                trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx),
                        LEFT.br_blockcount + PREV.br_blockcount +
                        RIGHT.br_blockcount);
                trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

                xfs_iext_remove(ip, *idx + 1, 2, state);
                ip->i_d.di_nextents -= 2;
                if (cur == NULL)
                        rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
                else {
                        rval = XFS_ILOG_CORE;
                        if ((error = xfs_bmbt_lookup_eq(cur, RIGHT.br_startoff,
                                        RIGHT.br_startblock,
                                        RIGHT.br_blockcount, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_btree_delete(cur, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_btree_decrement(cur, 0, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_btree_delete(cur, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_btree_decrement(cur, 0, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_bmbt_update(cur, LEFT.br_startoff,
                                LEFT.br_startblock,
                                LEFT.br_blockcount + PREV.br_blockcount +
                                RIGHT.br_blockcount, LEFT.br_state)))
                                goto done;
                }
                break;

        case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG:
                /*
                 * Setting all of a previous oldext extent to newext.
                 * The left neighbor is contiguous, the right is not.
                 */
                --*idx;

                trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx),
                        LEFT.br_blockcount + PREV.br_blockcount);
                trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

                xfs_iext_remove(ip, *idx + 1, 1, state);
                ip->i_d.di_nextents--;
                if (cur == NULL)
                        rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
                else {
                        rval = XFS_ILOG_CORE;
                        if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
                                        PREV.br_startblock, PREV.br_blockcount,
                                        &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_btree_delete(cur, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_btree_decrement(cur, 0, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_bmbt_update(cur, LEFT.br_startoff,
                                LEFT.br_startblock,
                                LEFT.br_blockcount + PREV.br_blockcount,
                                LEFT.br_state)))
                                goto done;
                }
                break;

        case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
                /*
                 * Setting all of a previous oldext extent to newext.
                 * The right neighbor is contiguous, the left is not.
                 */
                trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(ep,
                        PREV.br_blockcount + RIGHT.br_blockcount);
                xfs_bmbt_set_state(ep, newext);
                trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
                xfs_iext_remove(ip, *idx + 1, 1, state);
                ip->i_d.di_nextents--;
                if (cur == NULL)
                        rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
                else {
                        rval = XFS_ILOG_CORE;
                        if ((error = xfs_bmbt_lookup_eq(cur, RIGHT.br_startoff,
                                        RIGHT.br_startblock,
                                        RIGHT.br_blockcount, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_btree_delete(cur, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_btree_decrement(cur, 0, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_bmbt_update(cur, new->br_startoff,
                                new->br_startblock,
                                new->br_blockcount + RIGHT.br_blockcount,
                                newext)))
                                goto done;
                }
                break;

        case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING:
                /*
                 * Setting all of a previous oldext extent to newext.
                 * Neither the left nor right neighbors are contiguous with
                 * the new one.
                 */
                trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
                xfs_bmbt_set_state(ep, newext);
                trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

                if (cur == NULL)
                        rval = XFS_ILOG_DEXT;
                else {
                        rval = 0;
                        if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff,
                                        new->br_startblock, new->br_blockcount,
                                        &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_bmbt_update(cur, new->br_startoff,
                                new->br_startblock, new->br_blockcount,
                                newext)))
                                goto done;
                }
                break;

        case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG:
                /*
                 * Setting the first part of a previous oldext extent to newext.
                 * The left neighbor is contiguous.
                 */
                trace_xfs_bmap_pre_update(ip, *idx - 1, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx - 1),
                        LEFT.br_blockcount + new->br_blockcount);
                xfs_bmbt_set_startoff(ep,
                        PREV.br_startoff + new->br_blockcount);
                trace_xfs_bmap_post_update(ip, *idx - 1, state, _THIS_IP_);

                trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
                xfs_bmbt_set_startblock(ep,
                        new->br_startblock + new->br_blockcount);
                xfs_bmbt_set_blockcount(ep,
                        PREV.br_blockcount - new->br_blockcount);
                trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

                --*idx;

                if (cur == NULL)
                        rval = XFS_ILOG_DEXT;
                else {
                        rval = 0;
                        if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
                                        PREV.br_startblock, PREV.br_blockcount,
                                        &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_bmbt_update(cur,
                                PREV.br_startoff + new->br_blockcount,
                                PREV.br_startblock + new->br_blockcount,
                                PREV.br_blockcount - new->br_blockcount,
                                oldext)))
                                goto done;
                        if ((error = xfs_btree_decrement(cur, 0, &i)))
                                goto done;
                        error = xfs_bmbt_update(cur, LEFT.br_startoff,
                                LEFT.br_startblock,
                                LEFT.br_blockcount + new->br_blockcount,
                                LEFT.br_state);
                        if (error)
                                goto done;
                }
                break;

        case BMAP_LEFT_FILLING:
                /*
                 * Setting the first part of a previous oldext extent to newext.
                 * The left neighbor is not contiguous.
                 */
                trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
                ASSERT(ep && xfs_bmbt_get_state(ep) == oldext);
                xfs_bmbt_set_startoff(ep, new_endoff);
                xfs_bmbt_set_blockcount(ep,
                        PREV.br_blockcount - new->br_blockcount);
                xfs_bmbt_set_startblock(ep,
                        new->br_startblock + new->br_blockcount);
                trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

                xfs_iext_insert(ip, *idx, 1, new, state);
                ip->i_d.di_nextents++;
                if (cur == NULL)
                        rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
                else {
                        rval = XFS_ILOG_CORE;
                        if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
                                        PREV.br_startblock, PREV.br_blockcount,
                                        &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_bmbt_update(cur,
                                PREV.br_startoff + new->br_blockcount,
                                PREV.br_startblock + new->br_blockcount,
                                PREV.br_blockcount - new->br_blockcount,
                                oldext)))
                                goto done;
                        cur->bc_rec.b = *new;
                        if ((error = xfs_btree_insert(cur, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                }
                break;

        case BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
                /*
                 * Setting the last part of a previous oldext extent to newext.
                 * The right neighbor is contiguous with the new allocation.
                 */
                trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(ep,
                        PREV.br_blockcount - new->br_blockcount);
                trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

                ++*idx;

                trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
                xfs_bmbt_set_allf(xfs_iext_get_ext(ifp, *idx),
                        new->br_startoff, new->br_startblock,
                        new->br_blockcount + RIGHT.br_blockcount, newext);
                trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

                if (cur == NULL)
                        rval = XFS_ILOG_DEXT;
                else {
                        rval = 0;
                        if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
                                        PREV.br_startblock,
                                        PREV.br_blockcount, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_bmbt_update(cur, PREV.br_startoff,
                                PREV.br_startblock,
                                PREV.br_blockcount - new->br_blockcount,
                                oldext)))
                                goto done;
                        if ((error = xfs_btree_increment(cur, 0, &i)))
                                goto done;
                        if ((error = xfs_bmbt_update(cur, new->br_startoff,
                                new->br_startblock,
                                new->br_blockcount + RIGHT.br_blockcount,
                                newext)))
                                goto done;
                }
                break;

        case BMAP_RIGHT_FILLING:
                /*
                 * Setting the last part of a previous oldext extent to newext.
                 * The right neighbor is not contiguous.
                 */
                trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
                xfs_bmbt_set_blockcount(ep,
                        PREV.br_blockcount - new->br_blockcount);
                trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

                ++*idx;
                xfs_iext_insert(ip, *idx, 1, new, state);

                ip->i_d.di_nextents++;
                if (cur == NULL)
                        rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
                else {
                        rval = XFS_ILOG_CORE;
                        if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
                                        PREV.br_startblock, PREV.br_blockcount,
                                        &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                        if ((error = xfs_bmbt_update(cur, PREV.br_startoff,
                                PREV.br_startblock,
                                PREV.br_blockcount - new->br_blockcount,
                                oldext)))
                                goto done;
                        if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff,
                                        new->br_startblock, new->br_blockcount,
                                        &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 0, done);
                        cur->bc_rec.b.br_state = XFS_EXT_NORM;
                        if ((error = xfs_btree_insert(cur, &i)))
                                goto done;
                        XFS_WANT_CORRUPTED_GOTO(i == 1, done);
                }
                break;

        case 0:
                /*
                 * Setting the middle part of a previous oldext extent to
                 * newext.  Contiguity is impossible here.