xfs_inode.c

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/*
 * 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 <linux/log2.h>

#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_buf_item.h"
#include "xfs_inode_item.h"
#include "xfs_btree.h"
#include "xfs_alloc.h"
#include "xfs_ialloc.h"
#include "xfs_bmap.h"
#include "xfs_error.h"
#include "xfs_utils.h"
#include "xfs_quota.h"
#include "xfs_filestream.h"
#include "xfs_vnodeops.h"
#include "xfs_trace.h"

kmem_zone_t *xfs_ifork_zone;
kmem_zone_t *xfs_inode_zone;

/*
 * Used in xfs_itruncate_extents().  This is the maximum number of extents
 * freed from a file in a single transaction.
 */
#define XFS_ITRUNC_MAX_EXTENTS  2

STATIC int xfs_iflush_int(xfs_inode_t *, xfs_buf_t *);
STATIC int xfs_iformat_local(xfs_inode_t *, xfs_dinode_t *, int, int);
STATIC int xfs_iformat_extents(xfs_inode_t *, xfs_dinode_t *, int);
STATIC int xfs_iformat_btree(xfs_inode_t *, xfs_dinode_t *, int);

/*
 * helper function to extract extent size hint from inode
 */
xfs_extlen_t
xfs_get_extsz_hint(
    struct xfs_inode    *ip)
{
    if ((ip->i_d.di_flags & XFS_DIFLAG_EXTSIZE) && ip->i_d.di_extsize)
        return ip->i_d.di_extsize;
    if (XFS_IS_REALTIME_INODE(ip))
        return ip->i_mount->m_sb.sb_rextsize;
    return 0;
}

#ifdef DEBUG
/*
 * Make sure that the extents in the given memory buffer
 * are valid.
 */
STATIC void
xfs_validate_extents(
    xfs_ifork_t     *ifp,
    int         nrecs,
    xfs_exntfmt_t       fmt)
{
    xfs_bmbt_irec_t     irec;
    xfs_bmbt_rec_host_t rec;
    int         i;

    for (i = 0; i < nrecs; i++) {
        xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, i);
        rec.l0 = get_unaligned(&ep->l0);
        rec.l1 = get_unaligned(&ep->l1);
        xfs_bmbt_get_all(&rec, &irec);
        if (fmt == XFS_EXTFMT_NOSTATE)
            ASSERT(irec.br_state == XFS_EXT_NORM);
    }
}
#else /* DEBUG */
#define xfs_validate_extents(ifp, nrecs, fmt)
#endif /* DEBUG */

/*
 * Check that none of the inode's in the buffer have a next
 * unlinked field of 0.
 */
#if defined(DEBUG)
void
xfs_inobp_check(
    xfs_mount_t *mp,
    xfs_buf_t   *bp)
{
    int     i;
    int     j;
    xfs_dinode_t    *dip;

    j = mp->m_inode_cluster_size >> mp->m_sb.sb_inodelog;

    for (i = 0; i < j; i++) {
        dip = (xfs_dinode_t *)xfs_buf_offset(bp,
                    i * mp->m_sb.sb_inodesize);
        if (!dip->di_next_unlinked)  {
            xfs_alert(mp,
    "Detected bogus zero next_unlinked field in incore inode buffer 0x%p.",
                bp);
            ASSERT(dip->di_next_unlinked);
        }
    }
}
#endif

/*
 * This routine is called to map an inode to the buffer containing the on-disk
 * version of the inode.  It returns a pointer to the buffer containing the
 * on-disk inode in the bpp parameter, and in the dipp parameter it returns a
 * pointer to the on-disk inode within that buffer.
 *
 * If a non-zero error is returned, then the contents of bpp and dipp are
 * undefined.
 */
int
xfs_imap_to_bp(
    struct xfs_mount    *mp,
    struct xfs_trans    *tp,
    struct xfs_imap     *imap,
    struct xfs_dinode   **dipp,
    struct xfs_buf      **bpp,
    uint            buf_flags,
    uint            iget_flags)
{
    struct xfs_buf      *bp;
    int         error;
    int         i;
    int         ni;

    buf_flags |= XBF_UNMAPPED;
    error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, imap->im_blkno,
                   (int)imap->im_len, buf_flags, &bp);
    if (error) {
        if (error != EAGAIN) {
            xfs_warn(mp,
                "%s: xfs_trans_read_buf() returned error %d.",
                __func__, error);
        } else {
            ASSERT(buf_flags & XBF_TRYLOCK);
        }
        return error;
    }

    /*
     * Validate the magic number and version of every inode in the buffer
     * (if DEBUG kernel) or the first inode in the buffer, otherwise.
     */
#ifdef DEBUG
    ni = BBTOB(imap->im_len) >> mp->m_sb.sb_inodelog;
#else   /* usual case */
    ni = 1;
#endif

    for (i = 0; i < ni; i++) {
        int     di_ok;
        xfs_dinode_t    *dip;

        dip = (xfs_dinode_t *)xfs_buf_offset(bp,
                    (i << mp->m_sb.sb_inodelog));
        di_ok = dip->di_magic == cpu_to_be16(XFS_DINODE_MAGIC) &&
                XFS_DINODE_GOOD_VERSION(dip->di_version);
        if (unlikely(XFS_TEST_ERROR(!di_ok, mp,
                        XFS_ERRTAG_ITOBP_INOTOBP,
                        XFS_RANDOM_ITOBP_INOTOBP))) {
            if (iget_flags & XFS_IGET_UNTRUSTED) {
                xfs_trans_brelse(tp, bp);
                return XFS_ERROR(EINVAL);
            }
            XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_HIGH,
                         mp, dip);
#ifdef DEBUG
            xfs_emerg(mp,
                "bad inode magic/vsn daddr %lld #%d (magic=%x)",
                (unsigned long long)imap->im_blkno, i,
                be16_to_cpu(dip->di_magic));
            ASSERT(0);
#endif
            xfs_trans_brelse(tp, bp);
            return XFS_ERROR(EFSCORRUPTED);
        }
    }

    xfs_inobp_check(mp, bp);

    *bpp = bp;
    *dipp = (struct xfs_dinode *)xfs_buf_offset(bp, imap->im_boffset);
    return 0;
}

/*
 * Move inode type and inode format specific information from the
 * on-disk inode to the in-core inode.  For fifos, devs, and sockets
 * this means set if_rdev to the proper value.  For files, directories,
 * and symlinks this means to bring in the in-line data or extent
 * pointers.  For a file in B-tree format, only the root is immediately
 * brought in-core.  The rest will be in-lined in if_extents when it
 * is first referenced (see xfs_iread_extents()).
 */
STATIC int
xfs_iformat(
    xfs_inode_t     *ip,
    xfs_dinode_t        *dip)
{
    xfs_attr_shortform_t    *atp;
    int         size;
    int         error = 0;
    xfs_fsize_t             di_size;

    if (unlikely(be32_to_cpu(dip->di_nextents) +
             be16_to_cpu(dip->di_anextents) >
             be64_to_cpu(dip->di_nblocks))) {
        xfs_warn(ip->i_mount,
            "corrupt dinode %Lu, extent total = %d, nblocks = %Lu.",
            (unsigned long long)ip->i_ino,
            (int)(be32_to_cpu(dip->di_nextents) +
                  be16_to_cpu(dip->di_anextents)),
            (unsigned long long)
                be64_to_cpu(dip->di_nblocks));
        XFS_CORRUPTION_ERROR("xfs_iformat(1)", XFS_ERRLEVEL_LOW,
                     ip->i_mount, dip);
        return XFS_ERROR(EFSCORRUPTED);
    }

    if (unlikely(dip->di_forkoff > ip->i_mount->m_sb.sb_inodesize)) {
        xfs_warn(ip->i_mount, "corrupt dinode %Lu, forkoff = 0x%x.",
            (unsigned long long)ip->i_ino,
            dip->di_forkoff);
        XFS_CORRUPTION_ERROR("xfs_iformat(2)", XFS_ERRLEVEL_LOW,
                     ip->i_mount, dip);
        return XFS_ERROR(EFSCORRUPTED);
    }

    if (unlikely((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) &&
             !ip->i_mount->m_rtdev_targp)) {
        xfs_warn(ip->i_mount,
            "corrupt dinode %Lu, has realtime flag set.",
            ip->i_ino);
        XFS_CORRUPTION_ERROR("xfs_iformat(realtime)",
                     XFS_ERRLEVEL_LOW, ip->i_mount, dip);
        return XFS_ERROR(EFSCORRUPTED);
    }

    switch (ip->i_d.di_mode & S_IFMT) {
    case S_IFIFO:
    case S_IFCHR:
    case S_IFBLK:
    case S_IFSOCK:
        if (unlikely(dip->di_format != XFS_DINODE_FMT_DEV)) {
            XFS_CORRUPTION_ERROR("xfs_iformat(3)", XFS_ERRLEVEL_LOW,
                          ip->i_mount, dip);
            return XFS_ERROR(EFSCORRUPTED);
        }
        ip->i_d.di_size = 0;
        ip->i_df.if_u2.if_rdev = xfs_dinode_get_rdev(dip);
        break;

    case S_IFREG:
    case S_IFLNK:
    case S_IFDIR:
        switch (dip->di_format) {
        case XFS_DINODE_FMT_LOCAL:
            /*
             * no local regular files yet
             */
            if (unlikely(S_ISREG(be16_to_cpu(dip->di_mode)))) {
                xfs_warn(ip->i_mount,
            "corrupt inode %Lu (local format for regular file).",
                    (unsigned long long) ip->i_ino);
                XFS_CORRUPTION_ERROR("xfs_iformat(4)",
                             XFS_ERRLEVEL_LOW,
                             ip->i_mount, dip);
                return XFS_ERROR(EFSCORRUPTED);
            }

            di_size = be64_to_cpu(dip->di_size);
            if (unlikely(di_size > XFS_DFORK_DSIZE(dip, ip->i_mount))) {
                xfs_warn(ip->i_mount,
            "corrupt inode %Lu (bad size %Ld for local inode).",
                    (unsigned long long) ip->i_ino,
                    (long long) di_size);
                XFS_CORRUPTION_ERROR("xfs_iformat(5)",
                             XFS_ERRLEVEL_LOW,
                             ip->i_mount, dip);
                return XFS_ERROR(EFSCORRUPTED);
            }

            size = (int)di_size;
            error = xfs_iformat_local(ip, dip, XFS_DATA_FORK, size);
            break;
        case XFS_DINODE_FMT_EXTENTS:
            error = xfs_iformat_extents(ip, dip, XFS_DATA_FORK);
            break;
        case XFS_DINODE_FMT_BTREE:
            error = xfs_iformat_btree(ip, dip, XFS_DATA_FORK);
            break;
        default:
            XFS_ERROR_REPORT("xfs_iformat(6)", XFS_ERRLEVEL_LOW,
                     ip->i_mount);
            return XFS_ERROR(EFSCORRUPTED);
        }
        break;

    default:
        XFS_ERROR_REPORT("xfs_iformat(7)", XFS_ERRLEVEL_LOW, ip->i_mount);
        return XFS_ERROR(EFSCORRUPTED);
    }
    if (error) {
        return error;
    }
    if (!XFS_DFORK_Q(dip))
        return 0;

    ASSERT(ip->i_afp == NULL);
    ip->i_afp = kmem_zone_zalloc(xfs_ifork_zone, KM_SLEEP | KM_NOFS);

    switch (dip->di_aformat) {
    case XFS_DINODE_FMT_LOCAL:
        atp = (xfs_attr_shortform_t *)XFS_DFORK_APTR(dip);
        size = be16_to_cpu(atp->hdr.totsize);

        if (unlikely(size < sizeof(struct xfs_attr_sf_hdr))) {
            xfs_warn(ip->i_mount,
                "corrupt inode %Lu (bad attr fork size %Ld).",
                (unsigned long long) ip->i_ino,
                (long long) size);
            XFS_CORRUPTION_ERROR("xfs_iformat(8)",
                         XFS_ERRLEVEL_LOW,
                         ip->i_mount, dip);
            return XFS_ERROR(EFSCORRUPTED);
        }

        error = xfs_iformat_local(ip, dip, XFS_ATTR_FORK, size);
        break;
    case XFS_DINODE_FMT_EXTENTS:
        error = xfs_iformat_extents(ip, dip, XFS_ATTR_FORK);
        break;
    case XFS_DINODE_FMT_BTREE:
        error = xfs_iformat_btree(ip, dip, XFS_ATTR_FORK);
        break;
    default:
        error = XFS_ERROR(EFSCORRUPTED);
        break;
    }
    if (error) {
        kmem_zone_free(xfs_ifork_zone, ip->i_afp);
        ip->i_afp = NULL;
        xfs_idestroy_fork(ip, XFS_DATA_FORK);
    }
    return error;
}

/*
 * The file is in-lined in the on-disk inode.
 * If it fits into if_inline_data, then copy
 * it there, otherwise allocate a buffer for it
 * and copy the data there.  Either way, set
 * if_data to point at the data.
 * If we allocate a buffer for the data, make
 * sure that its size is a multiple of 4 and
 * record the real size in i_real_bytes.
 */
STATIC int
xfs_iformat_local(
    xfs_inode_t *ip,
    xfs_dinode_t    *dip,
    int     whichfork,
    int     size)
{
    xfs_ifork_t *ifp;
    int     real_size;

    /*
     * If the size is unreasonable, then something
     * is wrong and we just bail out rather than crash in
     * kmem_alloc() or memcpy() below.
     */
    if (unlikely(size > XFS_DFORK_SIZE(dip, ip->i_mount, whichfork))) {
        xfs_warn(ip->i_mount,
    "corrupt inode %Lu (bad size %d for local fork, size = %d).",
            (unsigned long long) ip->i_ino, size,
            XFS_DFORK_SIZE(dip, ip->i_mount, whichfork));
        XFS_CORRUPTION_ERROR("xfs_iformat_local", XFS_ERRLEVEL_LOW,
                     ip->i_mount, dip);
        return XFS_ERROR(EFSCORRUPTED);
    }
    ifp = XFS_IFORK_PTR(ip, whichfork);
    real_size = 0;
    if (size == 0)
        ifp->if_u1.if_data = NULL;
    else if (size <= sizeof(ifp->if_u2.if_inline_data))
        ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
    else {
        real_size = roundup(size, 4);
        ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP | KM_NOFS);
    }
    ifp->if_bytes = size;
    ifp->if_real_bytes = real_size;
    if (size)
        memcpy(ifp->if_u1.if_data, XFS_DFORK_PTR(dip, whichfork), size);
    ifp->if_flags &= ~XFS_IFEXTENTS;
    ifp->if_flags |= XFS_IFINLINE;
    return 0;
}

/*
 * The file consists of a set of extents all
 * of which fit into the on-disk inode.
 * If there are few enough extents to fit into
 * the if_inline_ext, then copy them there.
 * Otherwise allocate a buffer for them and copy
 * them into it.  Either way, set if_extents
 * to point at the extents.
 */
STATIC int
xfs_iformat_extents(
    xfs_inode_t *ip,
    xfs_dinode_t    *dip,
    int     whichfork)
{
    xfs_bmbt_rec_t  *dp;
    xfs_ifork_t *ifp;
    int     nex;
    int     size;
    int     i;

    ifp = XFS_IFORK_PTR(ip, whichfork);
    nex = XFS_DFORK_NEXTENTS(dip, whichfork);
    size = nex * (uint)sizeof(xfs_bmbt_rec_t);

    /*
     * If the number of extents is unreasonable, then something
     * is wrong and we just bail out rather than crash in
     * kmem_alloc() or memcpy() below.
     */
    if (unlikely(size < 0 || size > XFS_DFORK_SIZE(dip, ip->i_mount, whichfork))) {
        xfs_warn(ip->i_mount, "corrupt inode %Lu ((a)extents = %d).",
            (unsigned long long) ip->i_ino, nex);
        XFS_CORRUPTION_ERROR("xfs_iformat_extents(1)", XFS_ERRLEVEL_LOW,
                     ip->i_mount, dip);
        return XFS_ERROR(EFSCORRUPTED);
    }

    ifp->if_real_bytes = 0;
    if (nex == 0)
        ifp->if_u1.if_extents = NULL;
    else if (nex <= XFS_INLINE_EXTS)
        ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
    else
        xfs_iext_add(ifp, 0, nex);

    ifp->if_bytes = size;
    if (size) {
        dp = (xfs_bmbt_rec_t *) XFS_DFORK_PTR(dip, whichfork);
        xfs_validate_extents(ifp, nex, XFS_EXTFMT_INODE(ip));
        for (i = 0; i < nex; i++, dp++) {
            xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, i);
            ep->l0 = get_unaligned_be64(&dp->l0);
            ep->l1 = get_unaligned_be64(&dp->l1);
        }
        XFS_BMAP_TRACE_EXLIST(ip, nex, whichfork);
        if (whichfork != XFS_DATA_FORK ||
            XFS_EXTFMT_INODE(ip) == XFS_EXTFMT_NOSTATE)
                if (unlikely(xfs_check_nostate_extents(
                    ifp, 0, nex))) {
                    XFS_ERROR_REPORT("xfs_iformat_extents(2)",
                             XFS_ERRLEVEL_LOW,
                             ip->i_mount);
                    return XFS_ERROR(EFSCORRUPTED);
                }
    }
    ifp->if_flags |= XFS_IFEXTENTS;
    return 0;
}

/*
 * The file has too many extents to fit into
 * the inode, so they are in B-tree format.
 * Allocate a buffer for the root of the B-tree
 * and copy the root into it.  The i_extents
 * field will remain NULL until all of the
 * extents are read in (when they are needed).
 */
STATIC int
xfs_iformat_btree(
    xfs_inode_t     *ip,
    xfs_dinode_t        *dip,
    int         whichfork)
{
    xfs_bmdr_block_t    *dfp;
    xfs_ifork_t     *ifp;
    /* REFERENCED */
    int         nrecs;
    int         size;

    ifp = XFS_IFORK_PTR(ip, whichfork);
    dfp = (xfs_bmdr_block_t *)XFS_DFORK_PTR(dip, whichfork);
    size = XFS_BMAP_BROOT_SPACE(dfp);
    nrecs = be16_to_cpu(dfp->bb_numrecs);

    /*
     * blow out if -- fork has less extents than can fit in
     * fork (fork shouldn't be a btree format), root btree
     * block has more records than can fit into the fork,
     * or the number of extents is greater than the number of
     * blocks.
     */
    if (unlikely(XFS_IFORK_NEXTENTS(ip, whichfork) <=
            XFS_IFORK_MAXEXT(ip, whichfork) ||
             XFS_BMDR_SPACE_CALC(nrecs) >
            XFS_DFORK_SIZE(dip, ip->i_mount, whichfork) ||
             XFS_IFORK_NEXTENTS(ip, whichfork) > ip->i_d.di_nblocks)) {
        xfs_warn(ip->i_mount, "corrupt inode %Lu (btree).",
            (unsigned long long) ip->i_ino);
        XFS_CORRUPTION_ERROR("xfs_iformat_btree", XFS_ERRLEVEL_LOW,
                 ip->i_mount, dip);
        return XFS_ERROR(EFSCORRUPTED);
    }

    ifp->if_broot_bytes = size;
    ifp->if_broot = kmem_alloc(size, KM_SLEEP | KM_NOFS);
    ASSERT(ifp->if_broot != NULL);
    /*
     * Copy and convert from the on-disk structure
     * to the in-memory structure.
     */
    xfs_bmdr_to_bmbt(ip->i_mount, dfp,
             XFS_DFORK_SIZE(dip, ip->i_mount, whichfork),
             ifp->if_broot, size);
    ifp->if_flags &= ~XFS_IFEXTENTS;
    ifp->if_flags |= XFS_IFBROOT;

    return 0;
}

STATIC void
xfs_dinode_from_disk(
    xfs_icdinode_t      *to,
    xfs_dinode_t        *from)
{
    to->di_magic = be16_to_cpu(from->di_magic);
    to->di_mode = be16_to_cpu(from->di_mode);
    to->di_version = from ->di_version;
    to->di_format = from->di_format;
    to->di_onlink = be16_to_cpu(from->di_onlink);
    to->di_uid = be32_to_cpu(from->di_uid);
    to->di_gid = be32_to_cpu(from->di_gid);
    to->di_nlink = be32_to_cpu(from->di_nlink);
    to->di_projid_lo = be16_to_cpu(from->di_projid_lo);
    to->di_projid_hi = be16_to_cpu(from->di_projid_hi);
    memcpy(to->di_pad, from->di_pad, sizeof(to->di_pad));
    to->di_flushiter = be16_to_cpu(from->di_flushiter);
    to->di_atime.t_sec = be32_to_cpu(from->di_atime.t_sec);
    to->di_atime.t_nsec = be32_to_cpu(from->di_atime.t_nsec);
    to->di_mtime.t_sec = be32_to_cpu(from->di_mtime.t_sec);
    to->di_mtime.t_nsec = be32_to_cpu(from->di_mtime.t_nsec);
    to->di_ctime.t_sec = be32_to_cpu(from->di_ctime.t_sec);
    to->di_ctime.t_nsec = be32_to_cpu(from->di_ctime.t_nsec);
    to->di_size = be64_to_cpu(from->di_size);
    to->di_nblocks = be64_to_cpu(from->di_nblocks);
    to->di_extsize = be32_to_cpu(from->di_extsize);
    to->di_nextents = be32_to_cpu(from->di_nextents);
    to->di_anextents = be16_to_cpu(from->di_anextents);
    to->di_forkoff = from->di_forkoff;
    to->di_aformat  = from->di_aformat;
    to->di_dmevmask = be32_to_cpu(from->di_dmevmask);
    to->di_dmstate  = be16_to_cpu(from->di_dmstate);
    to->di_flags    = be16_to_cpu(from->di_flags);
    to->di_gen  = be32_to_cpu(from->di_gen);
}

void
xfs_dinode_to_disk(
    xfs_dinode_t        *to,
    xfs_icdinode_t      *from)
{
    to->di_magic = cpu_to_be16(from->di_magic);
    to->di_mode = cpu_to_be16(from->di_mode);
    to->di_version = from ->di_version;
    to->di_format = from->di_format;
    to->di_onlink = cpu_to_be16(from->di_onlink);
    to->di_uid = cpu_to_be32(from->di_uid);
    to->di_gid = cpu_to_be32(from->di_gid);
    to->di_nlink = cpu_to_be32(from->di_nlink);
    to->di_projid_lo = cpu_to_be16(from->di_projid_lo);
    to->di_projid_hi = cpu_to_be16(from->di_projid_hi);
    memcpy(to->di_pad, from->di_pad, sizeof(to->di_pad));
    to->di_flushiter = cpu_to_be16(from->di_flushiter);
    to->di_atime.t_sec = cpu_to_be32(from->di_atime.t_sec);
    to->di_atime.t_nsec = cpu_to_be32(from->di_atime.t_nsec);
    to->di_mtime.t_sec = cpu_to_be32(from->di_mtime.t_sec);
    to->di_mtime.t_nsec = cpu_to_be32(from->di_mtime.t_nsec);
    to->di_ctime.t_sec = cpu_to_be32(from->di_ctime.t_sec);
    to->di_ctime.t_nsec = cpu_to_be32(from->di_ctime.t_nsec);
    to->di_size = cpu_to_be64(from->di_size);
    to->di_nblocks = cpu_to_be64(from->di_nblocks);
    to->di_extsize = cpu_to_be32(from->di_extsize);
    to->di_nextents = cpu_to_be32(from->di_nextents);
    to->di_anextents = cpu_to_be16(from->di_anextents);
    to->di_forkoff = from->di_forkoff;
    to->di_aformat = from->di_aformat;
    to->di_dmevmask = cpu_to_be32(from->di_dmevmask);
    to->di_dmstate = cpu_to_be16(from->di_dmstate);
    to->di_flags = cpu_to_be16(from->di_flags);
    to->di_gen = cpu_to_be32(from->di_gen);
}

STATIC uint
_xfs_dic2xflags(
    __uint16_t      di_flags)
{
    uint            flags = 0;

    if (di_flags & XFS_DIFLAG_ANY) {
        if (di_flags & XFS_DIFLAG_REALTIME)
            flags |= XFS_XFLAG_REALTIME;
        if (di_flags & XFS_DIFLAG_PREALLOC)
            flags |= XFS_XFLAG_PREALLOC;
        if (di_flags & XFS_DIFLAG_IMMUTABLE)
            flags |= XFS_XFLAG_IMMUTABLE;
        if (di_flags & XFS_DIFLAG_APPEND)
            flags |= XFS_XFLAG_APPEND;
        if (di_flags & XFS_DIFLAG_SYNC)
            flags |= XFS_XFLAG_SYNC;
        if (di_flags & XFS_DIFLAG_NOATIME)
            flags |= XFS_XFLAG_NOATIME;
        if (di_flags & XFS_DIFLAG_NODUMP)
            flags |= XFS_XFLAG_NODUMP;
        if (di_flags & XFS_DIFLAG_RTINHERIT)
            flags |= XFS_XFLAG_RTINHERIT;
        if (di_flags & XFS_DIFLAG_PROJINHERIT)
            flags |= XFS_XFLAG_PROJINHERIT;
        if (di_flags & XFS_DIFLAG_NOSYMLINKS)
            flags |= XFS_XFLAG_NOSYMLINKS;
        if (di_flags & XFS_DIFLAG_EXTSIZE)
            flags |= XFS_XFLAG_EXTSIZE;
        if (di_flags & XFS_DIFLAG_EXTSZINHERIT)
            flags |= XFS_XFLAG_EXTSZINHERIT;
        if (di_flags & XFS_DIFLAG_NODEFRAG)
            flags |= XFS_XFLAG_NODEFRAG;
        if (di_flags & XFS_DIFLAG_FILESTREAM)
            flags |= XFS_XFLAG_FILESTREAM;
    }

    return flags;
}

uint
xfs_ip2xflags(
    xfs_inode_t     *ip)
{
    xfs_icdinode_t      *dic = &ip->i_d;

    return _xfs_dic2xflags(dic->di_flags) |
                (XFS_IFORK_Q(ip) ? XFS_XFLAG_HASATTR : 0);
}

uint
xfs_dic2xflags(
    xfs_dinode_t        *dip)
{
    return _xfs_dic2xflags(be16_to_cpu(dip->di_flags)) |
                (XFS_DFORK_Q(dip) ? XFS_XFLAG_HASATTR : 0);
}

/*
 * Read the disk inode attributes into the in-core inode structure.
 */
int
xfs_iread(
    xfs_mount_t *mp,
    xfs_trans_t *tp,
    xfs_inode_t *ip,
    uint        iget_flags)
{
    xfs_buf_t   *bp;
    xfs_dinode_t    *dip;
    int     error;

    /*
     * Fill in the location information in the in-core inode.
     */
    error = xfs_imap(mp, tp, ip->i_ino, &ip->i_imap, iget_flags);
    if (error)
        return error;

    /*
     * Get pointers to the on-disk inode and the buffer containing it.
     */
    error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &dip, &bp, 0, iget_flags);
    if (error)
        return error;

    /*
     * If we got something that isn't an inode it means someone
     * (nfs or dmi) has a stale handle.
     */
    if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC)) {
#ifdef DEBUG
        xfs_alert(mp,
            "%s: dip->di_magic (0x%x) != XFS_DINODE_MAGIC (0x%x)",
            __func__, be16_to_cpu(dip->di_magic), XFS_DINODE_MAGIC);
#endif /* DEBUG */
        error = XFS_ERROR(EINVAL);
        goto out_brelse;
    }

    /*
     * If the on-disk inode is already linked to a directory
     * entry, copy all of the inode into the in-core inode.
     * xfs_iformat() handles copying in the inode format
     * specific information.
     * Otherwise, just get the truly permanent information.
     */
    if (dip->di_mode) {
        xfs_dinode_from_disk(&ip->i_d, dip);
        error = xfs_iformat(ip, dip);
        if (error)  {
#ifdef DEBUG
            xfs_alert(mp, "%s: xfs_iformat() returned error %d",
                __func__, error);
#endif /* DEBUG */
            goto out_brelse;
        }
    } else {
        ip->i_d.di_magic = be16_to_cpu(dip->di_magic);
        ip->i_d.di_version = dip->di_version;
        ip->i_d.di_gen = be32_to_cpu(dip->di_gen);
        ip->i_d.di_flushiter = be16_to_cpu(dip->di_flushiter);
        /*
         * Make sure to pull in the mode here as well in
         * case the inode is released without being used.
         * This ensures that xfs_inactive() will see that
         * the inode is already free and not try to mess
         * with the uninitialized part of it.
         */
        ip->i_d.di_mode = 0;
    }

    /*
     * The inode format changed when we moved the link count and
     * made it 32 bits long.  If this is an old format inode,
     * convert it in memory to look like a new one.  If it gets
     * flushed to disk we will convert back before flushing or
     * logging it.  We zero out the new projid field and the old link
     * count field.  We'll handle clearing the pad field (the remains
     * of the old uuid field) when we actually convert the inode to
     * the new format. We don't change the version number so that we
     * can distinguish this from a real new format inode.
     */
    if (ip->i_d.di_version == 1) {
        ip->i_d.di_nlink = ip->i_d.di_onlink;
        ip->i_d.di_onlink = 0;
        xfs_set_projid(ip, 0);
    }

    ip->i_delayed_blks = 0;

    /*
     * Mark the buffer containing the inode as something to keep
     * around for a while.  This helps to keep recently accessed
     * meta-data in-core longer.
     */
    xfs_buf_set_ref(bp, XFS_INO_REF);

    /*
     * Use xfs_trans_brelse() to release the buffer containing the
     * on-disk inode, because it was acquired with xfs_trans_read_buf()
     * in xfs_imap_to_bp() above.  If tp is NULL, this is just a normal
     * brelse().  If we're within a transaction, then xfs_trans_brelse()
     * will only release the buffer if it is not dirty within the
     * transaction.  It will be OK to release the buffer in this case,
     * because inodes on disk are never destroyed and we will be
     * locking the new in-core inode before putting it in the hash
     * table where other processes can find it.  Thus we don't have
     * to worry about the inode being changed just because we released
     * the buffer.
     */
 out_brelse:
    xfs_trans_brelse(tp, bp);
    return error;
}

/*
 * Read in extents from a btree-format inode.
 * Allocate and fill in if_extents.  Real work is done in xfs_bmap.c.
 */
int
xfs_iread_extents(
    xfs_trans_t *tp,
    xfs_inode_t *ip,
    int     whichfork)
{
    int     error;
    xfs_ifork_t *ifp;
    xfs_extnum_t    nextents;

    if (unlikely(XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE)) {
        XFS_ERROR_REPORT("xfs_iread_extents", XFS_ERRLEVEL_LOW,
                 ip->i_mount);
        return XFS_ERROR(EFSCORRUPTED);
    }
    nextents = XFS_IFORK_NEXTENTS(ip, whichfork);
    ifp = XFS_IFORK_PTR(ip, whichfork);

    /*
     * We know that the size is valid (it's checked in iformat_btree)
     */
    ifp->if_bytes = ifp->if_real_bytes = 0;
    ifp->if_flags |= XFS_IFEXTENTS;
    xfs_iext_add(ifp, 0, nextents);
    error = xfs_bmap_read_extents(tp, ip, whichfork);
    if (error) {
        xfs_iext_destroy(ifp);
        ifp->if_flags &= ~XFS_IFEXTENTS;
        return error;
    }
    xfs_validate_extents(ifp, nextents, XFS_EXTFMT_INODE(ip));
    return 0;
}

/*
 * Allocate an inode on disk and return a copy of its in-core version.
 * The in-core inode is locked exclusively.  Set mode, nlink, and rdev
 * appropriately within the inode.  The uid and gid for the inode are
 * set according to the contents of the given cred structure.
 *
 * Use xfs_dialloc() to allocate the on-disk inode. If xfs_dialloc()
 * has a free inode available, call xfs_iget()
 * to obtain the in-core version of the allocated inode.  Finally,
 * fill in the inode and log its initial contents.  In this case,
 * ialloc_context would be set to NULL and call_again set to false.
 *
 * If xfs_dialloc() does not have an available inode,
 * it will replenish its supply by doing an allocation. Since we can
 * only do one allocation within a transaction without deadlocks, we
 * must commit the current transaction before returning the inode itself.
 * In this case, therefore, we will set call_again to true and return.
 * The caller should then commit the current transaction, start a new
 * transaction, and call xfs_ialloc() again to actually get the inode.
 *
 * To ensure that some other process does not grab the inode that
 * was allocated during the first call to xfs_ialloc(), this routine
 * also returns the [locked] bp pointing to the head of the freelist
 * as ialloc_context.  The caller should hold this buffer across
 * the commit and pass it back into this routine on the second call.
 *
 * If we are allocating quota inodes, we do not have a parent inode
 * to attach to or associate with (i.e. pip == NULL) because they
 * are not linked into the directory structure - they are attached
 * directly to the superblock - and so have no parent.
 */
int
xfs_ialloc(
    xfs_trans_t *tp,
    xfs_inode_t *pip,
    umode_t     mode,
    xfs_nlink_t nlink,
    xfs_dev_t   rdev,
    prid_t      prid,
    int     okalloc,
    xfs_buf_t   **ialloc_context,
    xfs_inode_t **ipp)
{
    xfs_ino_t   ino;
    xfs_inode_t *ip;
    uint        flags;
    int     error;
    timespec_t  tv;
    int     filestreams = 0;

    /*
     * Call the space management code to pick
     * the on-disk inode to be allocated.
     */
    error = xfs_dialloc(tp, pip ? pip->i_ino : 0, mode, okalloc,
                ialloc_context, &ino);
    if (error)
        return error;
    if (*ialloc_context || ino == NULLFSINO) {
        *ipp = NULL;
        return 0;
    }
    ASSERT(*ialloc_context == NULL);

    /*
     * Get the in-core inode with the lock held exclusively.
     * This is because we're setting fields here we need
     * to prevent others from looking at until we're done.
     */
    error = xfs_iget(tp->t_mountp, tp, ino, XFS_IGET_CREATE,
             XFS_ILOCK_EXCL, &ip);
    if (error)
        return error;
    ASSERT(ip != NULL);

    ip->i_d.di_mode = mode;
    ip->i_d.di_onlink = 0;
    ip->i_d.di_nlink = nlink;
    ASSERT(ip->i_d.di_nlink == nlink);
    ip->i_d.di_uid = current_fsuid();
    ip->i_d.di_gid = current_fsgid();
    xfs_set_projid(ip, prid);
    memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));

    /*
     * If the superblock version is up to where we support new format
     * inodes and this is currently an old format inode, then change
     * the inode version number now.  This way we only do the conversion
     * here rather than here and in the flush/logging code.
     */
    if (xfs_sb_version_hasnlink(&tp->t_mountp->m_sb) &&
        ip->i_d.di_version == 1) {
        ip->i_d.di_version = 2;
        /*
         * We've already zeroed the old link count, the projid field,
         * and the pad field.
         */
    }

    /*
     * Project ids won't be stored on disk if we are using a version 1 inode.
     */
    if ((prid != 0) && (ip->i_d.di_version == 1))
        xfs_bump_ino_vers2(tp, ip);

    if (pip && XFS_INHERIT_GID(pip)) {
        ip->i_d.di_gid = pip->i_d.di_gid;
        if ((pip->i_d.di_mode & S_ISGID) && S_ISDIR(mode)) {
            ip->i_d.di_mode |= S_ISGID;
        }
    }

    /*
     * If the group ID of the new file does not match the effective group
     * ID or one of the supplementary group IDs, the S_ISGID bit is cleared
     * (and only if the irix_sgid_inherit compatibility variable is set).
     */
    if ((irix_sgid_inherit) &&
        (ip->i_d.di_mode & S_ISGID) &&
        (!in_group_p((gid_t)ip->i_d.di_gid))) {
        ip->i_d.di_mode &= ~S_ISGID;
    }

    ip->i_d.di_size = 0;
    ip->i_d.di_nextents = 0;
    ASSERT(ip->i_d.di_nblocks == 0);

    nanotime(&tv);
    ip->i_d.di_mtime.t_sec = (__int32_t)tv.tv_sec;
    ip->i_d.di_mtime.t_nsec = (__int32_t)tv.tv_nsec;
    ip->i_d.di_atime = ip->i_d.di_mtime;
    ip->i_d.di_ctime = ip->i_d.di_mtime;

    /*
     * di_gen will have been taken care of in xfs_iread.
     */
    ip->i_d.di_extsize = 0;
    ip->i_d.di_dmevmask = 0;
    ip->i_d.di_dmstate = 0;
    ip->i_d.di_flags = 0;
    flags = XFS_ILOG_CORE;
    switch (mode & S_IFMT) {
    case S_IFIFO:
    case S_IFCHR:
    case S_IFBLK:
    case S_IFSOCK:
        ip->i_d.di_format = XFS_DINODE_FMT_DEV;
        ip->i_df.if_u2.if_rdev = rdev;
        ip->i_df.if_flags = 0;
        flags |= XFS_ILOG_DEV;
        break;
    case S_IFREG:
        /*
         * we can't set up filestreams until after the VFS inode
         * is set up properly.
         */
        if (pip && xfs_inode_is_filestream(pip))
            filestreams = 1;
        /* fall through */
    case S_IFDIR:
        if (pip && (pip->i_d.di_flags & XFS_DIFLAG_ANY)) {
            uint    di_flags = 0;

            if (S_ISDIR(mode)) {
                if (pip->i_d.di_flags & XFS_DIFLAG_RTINHERIT)
                    di_flags |= XFS_DIFLAG_RTINHERIT;
                if (pip->i_d.di_flags & XFS_DIFLAG_EXTSZINHERIT) {
                    di_flags |= XFS_DIFLAG_EXTSZINHERIT;
                    ip->i_d.di_extsize = pip->i_d.di_extsize;
                }
            } else if (S_ISREG(mode)) {
                if (pip->i_d.di_flags & XFS_DIFLAG_RTINHERIT)
                    di_flags |= XFS_DIFLAG_REALTIME;
                if (pip->i_d.di_flags & XFS_DIFLAG_EXTSZINHERIT) {
                    di_flags |= XFS_DIFLAG_EXTSIZE;
                    ip->i_d.di_extsize = pip->i_d.di_extsize;
                }
            }
            if ((pip->i_d.di_flags & XFS_DIFLAG_NOATIME) &&
                xfs_inherit_noatime)
                di_flags |= XFS_DIFLAG_NOATIME;
            if ((pip->i_d.di_flags & XFS_DIFLAG_NODUMP) &&
                xfs_inherit_nodump)
                di_flags |= XFS_DIFLAG_NODUMP;
            if ((pip->i_d.di_flags & XFS_DIFLAG_SYNC) &&
                xfs_inherit_sync)
                di_flags |= XFS_DIFLAG_SYNC;
            if ((pip->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) &&
                xfs_inherit_nosymlinks)
                di_flags |= XFS_DIFLAG_NOSYMLINKS;
            if (pip->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
                di_flags |= XFS_DIFLAG_PROJINHERIT;
            if ((pip->i_d.di_flags & XFS_DIFLAG_NODEFRAG) &&
                xfs_inherit_nodefrag)
                di_flags |= XFS_DIFLAG_NODEFRAG;
            if (pip->i_d.di_flags & XFS_DIFLAG_FILESTREAM)
                di_flags |= XFS_DIFLAG_FILESTREAM;
            ip->i_d.di_flags |= di_flags;
        }
        /* FALLTHROUGH */
    case S_IFLNK:
        ip->i_d.di_format = XFS_DINODE_FMT_EXTENTS;
        ip->i_df.if_flags = XFS_IFEXTENTS;
        ip->i_df.if_bytes = ip->i_df.if_real_bytes = 0;
        ip->i_df.if_u1.if_extents = NULL;
        break;
    default:
        ASSERT(0);
    }
    /*
     * Attribute fork settings for new inode.
     */
    ip->i_d.di_aformat = XFS_DINODE_FMT_EXTENTS;
    ip->i_d.di_anextents = 0;

    /*
     * Log the new values stuffed into the inode.
     */
    xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
    xfs_trans_log_inode(tp, ip, flags);

    /* now that we have an i_mode we can setup inode ops and unlock */
    xfs_setup_inode(ip);

    /* now we have set up the vfs inode we can associate the filestream */
    if (filestreams) {
        error = xfs_filestream_associate(pip, ip);
        if (error < 0)
            return -error;
        if (!error)
            xfs_iflags_set(ip, XFS_IFILESTREAM);
    }

    *ipp = ip;
    return 0;
}

/*
 * Free up the underlying blocks past new_size.  The new size must be smaller
 * than the current size.  This routine can be used both for the attribute and
 * data fork, and does not modify the inode size, which is left to the caller.
 *
 * The transaction passed to this routine must have made a permanent log
 * reservation of at least XFS_ITRUNCATE_LOG_RES.  This routine may commit the
 * given transaction and start new ones, so make sure everything involved in
 * the transaction is tidy before calling here.  Some transaction will be
 * returned to the caller to be committed.  The incoming transaction must
 * already include the inode, and both inode locks must be held exclusively.
 * The inode must also be "held" within the transaction.  On return the inode
 * will be "held" within the returned transaction.  This routine does NOT
 * require any disk space to be reserved for it within the transaction.
 *
 * If we get an error, we must return with the inode locked and linked into the
 * current transaction. This keeps things simple for the higher level code,
 * because it always knows that the inode is locked and held in the transaction
 * that returns to it whether errors occur or not.  We don't mark the inode
 * dirty on error so that transactions can be easily aborted if possible.
 */
int
xfs_itruncate_extents(
    struct xfs_trans    **tpp,
    struct xfs_inode    *ip,
    int         whichfork,
    xfs_fsize_t     new_size)
{
    struct xfs_mount    *mp = ip->i_mount;
    struct xfs_trans    *tp = *tpp;
    struct xfs_trans    *ntp;
    xfs_bmap_free_t     free_list;
    xfs_fsblock_t       first_block;
    xfs_fileoff_t       first_unmap_block;
    xfs_fileoff_t       last_block;
    xfs_filblks_t       unmap_len;
    int         committed;
    int         error = 0;
    int         done = 0;

    ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
    ASSERT(!atomic_read(&VFS_I(ip)->i_count) ||
           xfs_isilocked(ip, XFS_IOLOCK_EXCL));
    ASSERT(new_size <= XFS_ISIZE(ip));
    ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
    ASSERT(ip->i_itemp != NULL);
    ASSERT(ip->i_itemp->ili_lock_flags == 0);
    ASSERT(!XFS_NOT_DQATTACHED(mp, ip));

    trace_xfs_itruncate_extents_start(ip, new_size);

    /*
     * Since it is possible for space to become allocated beyond
     * the end of the file (in a crash where the space is allocated
     * but the inode size is not yet updated), simply remove any
     * blocks which show up between the new EOF and the maximum
     * possible file size.  If the first block to be removed is
     * beyond the maximum file size (ie it is the same as last_block),
     * then there is nothing to do.
     */
    first_unmap_block = XFS_B_TO_FSB(mp, (xfs_ufsize_t)new_size);
    last_block = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
    if (first_unmap_block == last_block)
        return 0;

    ASSERT(first_unmap_block < last_block);
    unmap_len = last_block - first_unmap_block + 1;
    while (!done) {
        xfs_bmap_init(&free_list, &first_block);
        error = xfs_bunmapi(tp, ip,
                    first_unmap_block, unmap_len,
                    xfs_bmapi_aflag(whichfork),
                    XFS_ITRUNC_MAX_EXTENTS,
                    &first_block, &free_list,
                    &done);
        if (error)
            goto out_bmap_cancel;

        /*
         * Duplicate the transaction that has the permanent
         * reservation and commit the old transaction.
         */
        error = xfs_bmap_finish(&tp, &free_list, &committed);
        if (committed)
            xfs_trans_ijoin(tp, ip, 0);
        if (error)
            goto out_bmap_cancel;

        if (committed) {
            /*
             * Mark the inode dirty so it will be logged and
             * moved forward in the log as part of every commit.
             */
            xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
        }

        ntp = xfs_trans_dup(tp);
        error = xfs_trans_commit(tp, 0);
        tp = ntp;

        xfs_trans_ijoin(tp, ip, 0);

        if (error)
            goto out;

        /*
         * Transaction commit worked ok so we can drop the extra ticket
         * reference that we gained in xfs_trans_dup()
         */
        xfs_log_ticket_put(tp->t_ticket);
        error = xfs_trans_reserve(tp, 0,
                    XFS_ITRUNCATE_LOG_RES(mp), 0,
                    XFS_TRANS_PERM_LOG_RES,
                    XFS_ITRUNCATE_LOG_COUNT);
        if (error)
            goto out;
    }

    /*
     * Always re-log the inode so that our permanent transaction can keep
     * on rolling it forward in the log.
     */
    xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

    trace_xfs_itruncate_extents_end(ip, new_size);

out:
    *tpp = tp;
    return error;
out_bmap_cancel:
    /*
     * If the bunmapi call encounters an error, return to the caller where
     * the transaction can be properly aborted.  We just need to make sure
     * we're not holding any resources that we were not when we came in.
     */
    xfs_bmap_cancel(&free_list);
    goto out;
}

/*
 * This is called when the inode's link count goes to 0.
 * We place the on-disk inode on a list in the AGI.  It
 * will be pulled from this list when the inode is freed.
 */
int
xfs_iunlink(
    xfs_trans_t *tp,
    xfs_inode_t *ip)
{
    xfs_mount_t *mp;
    xfs_agi_t   *agi;
    xfs_dinode_t    *dip;
    xfs_buf_t   *agibp;
    xfs_buf_t   *ibp;
    xfs_agino_t agino;
    short       bucket_index;
    int     offset;
    int     error;

    ASSERT(ip->i_d.di_nlink == 0);
    ASSERT(ip->i_d.di_mode != 0);

    mp = tp->t_mountp;

    /*
     * Get the agi buffer first.  It ensures lock ordering
     * on the list.
     */
    error = xfs_read_agi(mp, tp, XFS_INO_TO_AGNO(mp, ip->i_ino), &agibp);
    if (error)
        return error;
    agi = XFS_BUF_TO_AGI(agibp);

    /*
     * Get the index into the agi hash table for the
     * list this inode will go on.
     */
    agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
    ASSERT(agino != 0);
    bucket_index = agino % XFS_AGI_UNLINKED_BUCKETS;
    ASSERT(agi->agi_unlinked[bucket_index]);
    ASSERT(be32_to_cpu(agi->agi_unlinked[bucket_index]) != agino);

    if (agi->agi_unlinked[bucket_index] != cpu_to_be32(NULLAGINO)) {
        /*
         * There is already another inode in the bucket we need
         * to add ourselves to.  Add us at the front of the list.
         * Here we put the head pointer into our next pointer,
         * and then we fall through to point the head at us.
         */
        error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &dip, &ibp,
                       0, 0);
        if (error)
            return error;

        ASSERT(dip->di_next_unlinked == cpu_to_be32(NULLAGINO));
        dip->di_next_unlinked = agi->agi_unlinked[bucket_index];
        offset = ip->i_imap.im_boffset +
            offsetof(xfs_dinode_t, di_next_unlinked);
        xfs_trans_inode_buf(tp, ibp);
        xfs_trans_log_buf(tp, ibp, offset,
                  (offset + sizeof(xfs_agino_t) - 1));
        xfs_inobp_check(mp, ibp);
    }

    /*
     * Point the bucket head pointer at the inode being inserted.
     */
    ASSERT(agino != 0);
    agi->agi_unlinked[bucket_index] = cpu_to_be32(agino);
    offset = offsetof(xfs_agi_t, agi_unlinked) +
        (sizeof(xfs_agino_t) * bucket_index);
    xfs_trans_log_buf(tp, agibp, offset,
              (offset + sizeof(xfs_agino_t) - 1));
    return 0;
}

/*
 * Pull the on-disk inode from the AGI unlinked list.
 */
STATIC int
xfs_iunlink_remove(
    xfs_trans_t *tp,
    xfs_inode_t *ip)
{
    xfs_ino_t   next_ino;
    xfs_mount_t *mp;
    xfs_agi_t   *agi;
    xfs_dinode_t    *dip;
    xfs_buf_t   *agibp;
    xfs_buf_t   *ibp;
    xfs_agnumber_t  agno;
    xfs_agino_t agino;
    xfs_agino_t next_agino;
    xfs_buf_t   *last_ibp;
    xfs_dinode_t    *last_dip = NULL;
    short       bucket_index;
    int     offset, last_offset = 0;
    int     error;

    mp = tp->t_mountp;
    agno = XFS_INO_TO_AGNO(mp, ip->i_ino);

    /*
     * Get the agi buffer first.  It ensures lock ordering
     * on the list.
     */
    error = xfs_read_agi(mp, tp, agno, &agibp);
    if (error)
        return error;

    agi = XFS_BUF_TO_AGI(agibp);

    /*
     * Get the index into the agi hash table for the
     * list this inode will go on.
     */
    agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
    ASSERT(agino != 0);
    bucket_index = agino % XFS_AGI_UNLINKED_BUCKETS;
    ASSERT(agi->agi_unlinked[bucket_index] != cpu_to_be32(NULLAGINO));
    ASSERT(agi->agi_unlinked[bucket_index]);

    if (be32_to_cpu(agi->agi_unlinked[bucket_index]) == agino) {
        /*
         * We're at the head of the list.  Get the inode's on-disk
         * buffer to see if there is anyone after us on the list.
         * Only modify our next pointer if it is not already NULLAGINO.
         * This saves us the overhead of dealing with the buffer when
         * there is no need to change it.
         */
        error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &dip, &ibp,
                       0, 0);
        if (error) {
            xfs_warn(mp, "%s: xfs_imap_to_bp returned error %d.",
                __func__, error);
            return error;
        }
        next_agino = be32_to_cpu(dip->di_next_unlinked);
        ASSERT(next_agino != 0);
        if (next_agino != NULLAGINO) {
            dip->di_next_unlinked = cpu_to_be32(NULLAGINO);
            offset = ip->i_imap.im_boffset +
                offsetof(xfs_dinode_t, di_next_unlinked);
            xfs_trans_inode_buf(tp, ibp);
            xfs_trans_log_buf(tp, ibp, offset,
                      (offset + sizeof(xfs_agino_t) - 1));
            xfs_inobp_check(mp, ibp);
        } else {
            xfs_trans_brelse(tp, ibp);
        }
        /*
         * Point the bucket head pointer at the next inode.
         */
        ASSERT(next_agino != 0);
        ASSERT(next_agino != agino);
        agi->agi_unlinked[bucket_index] = cpu_to_be32(next_agino);
        offset = offsetof(xfs_agi_t, agi_unlinked) +
            (sizeof(xfs_agino_t) * bucket_index);
        xfs_trans_log_buf(tp, agibp, offset,
                  (offset + sizeof(xfs_agino_t) - 1));
    } else {
        /*
         * We need to search the list for the inode being freed.
         */
        next_agino = be32_to_cpu(agi->agi_unlinked[bucket_index]);
        last_ibp = NULL;
        while (next_agino != agino) {
            struct xfs_imap imap;

            if (last_ibp)
                xfs_trans_brelse(tp, last_ibp);

            imap.im_blkno = 0;
            next_ino = XFS_AGINO_TO_INO(mp, agno, next_agino);

            error = xfs_imap(mp, tp, next_ino, &imap, 0);
            if (error) {
                xfs_warn(mp,
    "%s: xfs_imap returned error %d.",
                     __func__, error);
                return error;
            }

            error = xfs_imap_to_bp(mp, tp, &imap, &last_dip,
                           &last_ibp, 0, 0);
            if (error) {
                xfs_warn(mp,
    "%s: xfs_imap_to_bp returned error %d.",
                    __func__, error);
                return error;
            }

            last_offset = imap.im_boffset;
            next_agino = be32_to_cpu(last_dip->di_next_unlinked);
            ASSERT(next_agino != NULLAGINO);
            ASSERT(next_agino != 0);
        }

        /*
         * Now last_ibp points to the buffer previous to us on the
         * unlinked list.  Pull us from the list.
         */
        error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &dip, &ibp,
                       0, 0);
        if (error) {
            xfs_warn(mp, "%s: xfs_imap_to_bp(2) returned error %d.",
                __func__, error);
            return error;
        }
        next_agino = be32_to_cpu(dip->di_next_unlinked);
        ASSERT(next_agino != 0);
        ASSERT(next_agino != agino);
        if (next_agino != NULLAGINO) {
            dip->di_next_unlinked = cpu_to_be32(NULLAGINO);
            offset = ip->i_imap.im_boffset +
                offsetof(xfs_dinode_t, di_next_unlinked);
            xfs_trans_inode_buf(tp, ibp);
            xfs_trans_log_buf(tp, ibp, offset,
                      (offset + sizeof(xfs_agino_t) - 1));
            xfs_inobp_check(mp, ibp);
        } else {
            xfs_trans_brelse(tp, ibp);
        }
        /*
         * Point the previous inode on the list to the next inode.
         */
        last_dip->di_next_unlinked = cpu_to_be32(next_agino);
        ASSERT(next_agino != 0);
        offset = last_offset + offsetof(xfs_dinode_t, di_next_unlinked);
        xfs_trans_inode_buf(tp, last_ibp);
        xfs_trans_log_buf(tp, last_ibp, offset,
                  (offset + sizeof(xfs_agino_t) - 1));
        xfs_inobp_check(mp, last_ibp);
    }
    return 0;
}

/*
 * A big issue when freeing the inode cluster is is that we _cannot_ skip any
 * inodes that are in memory - they all must be marked stale and attached to
 * the cluster buffer.
 */
STATIC int
xfs_ifree_cluster(
    xfs_inode_t *free_ip,
    xfs_trans_t *tp,
    xfs_ino_t   inum)
{
    xfs_mount_t     *mp = free_ip->i_mount;
    int         blks_per_cluster;
    int         nbufs;
    int         ninodes;
    int         i, j;
    xfs_daddr_t     blkno;
    xfs_buf_t       *bp;
    xfs_inode_t     *ip;
    xfs_inode_log_item_t    *iip;
    xfs_log_item_t      *lip;
    struct xfs_perag    *pag;

    pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, inum));
    if (mp->m_sb.sb_blocksize >= XFS_INODE_CLUSTER_SIZE(mp)) {
        blks_per_cluster = 1;
        ninodes = mp->m_sb.sb_inopblock;
        nbufs = XFS_IALLOC_BLOCKS(mp);
    } else {
        blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) /
                    mp->m_sb.sb_blocksize;
        ninodes = blks_per_cluster * mp->m_sb.sb_inopblock;
        nbufs = XFS_IALLOC_BLOCKS(mp) / blks_per_cluster;
    }

    for (j = 0; j < nbufs; j++, inum += ninodes) {
        blkno = XFS_AGB_TO_DADDR(mp, XFS_INO_TO_AGNO(mp, inum),
                     XFS_INO_TO_AGBNO(mp, inum));

        /*
         * We obtain and lock the backing buffer first in the process
         * here, as we have to ensure that any dirty inode that we
         * can't get the flush lock on is attached to the buffer.
         * If we scan the in-memory inodes first, then buffer IO can
         * complete before we get a lock on it, and hence we may fail
         * to mark all the active inodes on the buffer stale.
         */
        bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, blkno,
                    mp->m_bsize * blks_per_cluster,
                    XBF_UNMAPPED);

        if (!bp)
            return ENOMEM;
        /*
         * Walk the inodes already attached to the buffer and mark them
         * stale. These will all have the flush locks held, so an
         * in-memory inode walk can't lock them. By marking them all
         * stale first, we will not attempt to lock them in the loop
         * below as the XFS_ISTALE flag will be set.
         */
        lip = bp->b_fspriv;
        while (lip) {
            if (lip->li_type == XFS_LI_INODE) {
                iip = (xfs_inode_log_item_t *)lip;
                ASSERT(iip->ili_logged == 1);
                lip->li_cb = xfs_istale_done;
                xfs_trans_ail_copy_lsn(mp->m_ail,
                            &iip->ili_flush_lsn,
                            &iip->ili_item.li_lsn);
                xfs_iflags_set(iip->ili_inode, XFS_ISTALE);
            }
            lip = lip->li_bio_list;
        }


        /*
         * For each inode in memory attempt to add it to the inode
         * buffer and set it up for being staled on buffer IO
         * completion.  This is safe as we've locked out tail pushing
         * and flushing by locking the buffer.
         *
         * We have already marked every inode that was part of a
         * transaction stale above, which means there is no point in
         * even trying to lock them.
         */
        for (i = 0; i < ninodes; i++) {
retry:
            rcu_read_lock();
            ip = radix_tree_lookup(&pag->pag_ici_root,
                    XFS_INO_TO_AGINO(mp, (inum + i)));

            /* Inode not in memory, nothing to do */
            if (!ip) {
                rcu_read_unlock();
                continue;
            }

            /*
             * because this is an RCU protected lookup, we could
             * find a recently freed or even reallocated inode
             * during the lookup. We need to check under the
             * i_flags_lock for a valid inode here. Skip it if it
             * is not valid, the wrong inode or stale.
             */
            spin_lock(&ip->i_flags_lock);
            if (ip->i_ino != inum + i ||
                __xfs_iflags_test(ip, XFS_ISTALE)) {
                spin_unlock(&ip->i_flags_lock);
                rcu_read_unlock();
                continue;
            }
            spin_unlock(&ip->i_flags_lock);

            /*
             * Don't try to lock/unlock the current inode, but we
             * _cannot_ skip the other inodes that we did not find
             * in the list attached to the buffer and are not
             * already marked stale. If we can't lock it, back off
             * and retry.
             */
            if (ip != free_ip &&
                !xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) {
                rcu_read_unlock();
                delay(1);
                goto retry;
            }
            rcu_read_unlock();

            xfs_iflock(ip);
            xfs_iflags_set(ip, XFS_ISTALE);

            /*
             * we don't need to attach clean inodes or those only
             * with unlogged changes (which we throw away, anyway).
             */
            iip = ip->i_itemp;
            if (!iip || xfs_inode_clean(ip)) {
                ASSERT(ip != free_ip);
                xfs_ifunlock(ip);
                xfs_iunlock(ip, XFS_ILOCK_EXCL);
                continue;
            }

            iip->ili_last_fields = iip->ili_fields;
            iip->ili_fields = 0;
            iip->ili_logged = 1;
            xfs_trans_ail_copy_lsn(mp->m_ail, &iip->ili_flush_lsn,
                        &iip->ili_item.li_lsn);

            xfs_buf_attach_iodone(bp, xfs_istale_done,
                          &iip->ili_item);

            if (ip != free_ip)
                xfs_iunlock(ip, XFS_ILOCK_EXCL);
        }

        xfs_trans_stale_inode_buf(tp, bp);
        xfs_trans_binval(tp, bp);
    }

    xfs_perag_put(pag);
    return 0;
}

/*
 * This is called to return an inode to the inode free list.
 * The inode should already be truncated to 0 length and have
 * no pages associated with it.  This routine also assumes that
 * the inode is already a part of the transaction.
 *
 * The on-disk copy of the inode will have been added to the list
 * of unlinked inodes in the AGI. We need to remove the inode from
 * that list atomically with respect to freeing it here.
 */
int
xfs_ifree(
    xfs_trans_t *tp,
    xfs_inode_t *ip,
    xfs_bmap_free_t *flist)
{
    int         error;
    int         delete;
    xfs_ino_t       first_ino;
    xfs_dinode_t        *dip;
    xfs_buf_t           *ibp;

    ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
    ASSERT(ip->i_d.di_nlink == 0);
    ASSERT(ip->i_d.di_nextents == 0);
    ASSERT(ip->i_d.di_anextents == 0);
    ASSERT(ip->i_d.di_size == 0 || !S_ISREG(ip->i_d.di_mode));
    ASSERT(ip->i_d.di_nblocks == 0);

    /*
     * Pull the on-disk inode from the AGI unlinked list.
     */
    error = xfs_iunlink_remove(tp, ip);
    if (error != 0) {
        return error;
    }

    error = xfs_difree(tp, ip->i_ino, flist, &delete, &first_ino);
    if (error != 0) {
        return error;
    }
    ip->i_d.di_mode = 0;        /* mark incore inode as free */
    ip->i_d.di_flags = 0;
    ip->i_d.di_dmevmask = 0;
    ip->i_d.di_forkoff = 0;     /* mark the attr fork not in use */
    ip->i_d.di_format = XFS_DINODE_FMT_EXTENTS;
    ip->i_d.di_aformat = XFS_DINODE_FMT_EXTENTS;
    /*
     * Bump the generation count so no one will be confused
     * by reincarnations of this inode.
     */
    ip->i_d.di_gen++;

    xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

    error = xfs_imap_to_bp(ip->i_mount, tp, &ip->i_imap, &dip, &ibp,
                   0, 0);
    if (error)
        return error;

        /*
    * Clear the on-disk di_mode. This is to prevent xfs_bulkstat
    * from picking up this inode when it is reclaimed (its incore state
    * initialzed but not flushed to disk yet). The in-core di_mode is
    * already cleared  and a corresponding transaction logged.
    * The hack here just synchronizes the in-core to on-disk
    * di_mode value in advance before the actual inode sync to disk.
    * This is OK because the inode is already unlinked and would never
    * change its di_mode again for this inode generation.
    * This is a temporary hack that would require a proper fix
    * in the future.
    */
    dip->di_mode = 0;

    if (delete) {
        error = xfs_ifree_cluster(ip, tp, first_ino);
    }

    return error;
}

/*
 * Reallocate the space for if_broot based on the number of records
 * being added or deleted as indicated in rec_diff.  Move the records
 * and pointers in if_broot to fit the new size.  When shrinking this
 * will eliminate holes between the records and pointers created by
 * the caller.  When growing this will create holes to be filled in
 * by the caller.
 *
 * The caller must not request to add more records than would fit in
 * the on-disk inode root.  If the if_broot is currently NULL, then
 * if we adding records one will be allocated.  The caller must also
 * not request that the number of records go below zero, although
 * it can go to zero.
 *
 * ip -- the inode whose if_broot area is changing
 * ext_diff -- the change in the number of records, positive or negative,
 *   requested for the if_broot array.
 */
void
xfs_iroot_realloc(
    xfs_inode_t     *ip,
    int         rec_diff,
    int         whichfork)
{
    struct xfs_mount    *mp = ip->i_mount;
    int         cur_max;
    xfs_ifork_t     *ifp;
    struct xfs_btree_block  *new_broot;
    int         new_max;
    size_t          new_size;
    char            *np;
    char            *op;

    /*
     * Handle the degenerate case quietly.
     */
    if (rec_diff == 0) {
        return;
    }

    ifp = XFS_IFORK_PTR(ip, whichfork);
    if (rec_diff > 0) {
        /*
         * If there wasn't any memory allocated before, just
         * allocate it now and get out.
         */
        if (ifp->if_broot_bytes == 0) {
            new_size = (size_t)XFS_BMAP_BROOT_SPACE_CALC(rec_diff);
            ifp->if_broot = kmem_alloc(new_size, KM_SLEEP | KM_NOFS);
            ifp->if_broot_bytes = (int)new_size;
            return;
        }

        /*
         * If there is already an existing if_broot, then we need
         * to realloc() it and shift the pointers to their new
         * location.  The records don't change location because
         * they are kept butted up against the btree block header.
         */
        cur_max = xfs_bmbt_maxrecs(mp, ifp->if_broot_bytes, 0);
        new_max = cur_max + rec_diff;
        new_size = (size_t)XFS_BMAP_BROOT_SPACE_CALC(new_max);
        ifp->if_broot = kmem_realloc(ifp->if_broot, new_size,
                (size_t)XFS_BMAP_BROOT_SPACE_CALC(cur_max), /* old size */
                KM_SLEEP | KM_NOFS);
        op = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
                             ifp->if_broot_bytes);
        np = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
                             (int)new_size);
        ifp->if_broot_bytes = (int)new_size;
        ASSERT(ifp->if_broot_bytes <=
            XFS_IFORK_SIZE(ip, whichfork) + XFS_BROOT_SIZE_ADJ);
        memmove(np, op, cur_max * (uint)sizeof(xfs_dfsbno_t));
        return;
    }

    /*
     * rec_diff is less than 0.  In this case, we are shrinking the
     * if_broot buffer.  It must already exist.  If we go to zero
     * records, just get rid of the root and clear the status bit.
     */
    ASSERT((ifp->if_broot != NULL) && (ifp->if_broot_bytes > 0));
    cur_max = xfs_bmbt_maxrecs(mp, ifp->if_broot_bytes, 0);
    new_max = cur_max + rec_diff;
    ASSERT(new_max >= 0);
    if (new_max > 0)
        new_size = (size_t)XFS_BMAP_BROOT_SPACE_CALC(new_max);
    else
        new_size = 0;
    if (new_size > 0) {
        new_broot = kmem_alloc(new_size, KM_SLEEP | KM_NOFS);
        /*
         * First copy over the btree block header.
         */
        memcpy(new_broot, ifp->if_broot, XFS_BTREE_LBLOCK_LEN);
    } else {
        new_broot = NULL;
        ifp->if_flags &= ~XFS_IFBROOT;
    }

    /*
     * Only copy the records and pointers if there are any.
     */
    if (new_max > 0) {
        /*
         * First copy the records.
         */
        op = (char *)XFS_BMBT_REC_ADDR(mp, ifp->if_broot, 1);
        np = (char *)XFS_BMBT_REC_ADDR(mp, new_broot, 1);
        memcpy(np, op, new_max * (uint)sizeof(xfs_bmbt_rec_t));

        /*
         * Then copy the pointers.
         */
        op = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
                             ifp->if_broot_bytes);
        np = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, new_broot, 1,
                             (int)new_size);
        memcpy(np, op, new_max * (uint)sizeof(xfs_dfsbno_t));
    }
    kmem_free(ifp->if_broot);
    ifp->if_broot = new_broot;
    ifp->if_broot_bytes = (int)new_size;
    ASSERT(ifp->if_broot_bytes <=
        XFS_IFORK_SIZE(ip, whichfork) + XFS_BROOT_SIZE_ADJ);
    return;
}


/*
 * This is called when the amount of space needed for if_data
 * is increased or decreased.  The change in size is indicated by
 * the number of bytes that need to be added or deleted in the
 * byte_diff parameter.
 *
 * If the amount of space needed has decreased below the size of the
 * inline buffer, then switch to using the inline buffer.  Otherwise,
 * use kmem_realloc() or kmem_alloc() to adjust the size of the buffer
 * to what is needed.
 *
 * ip -- the inode whose if_data area is changing
 * byte_diff -- the change in the number of bytes, positive or negative,
 *   requested for the if_data array.
 */
void
xfs_idata_realloc(
    xfs_inode_t *ip,
    int     byte_diff,
    int     whichfork)
{
    xfs_ifork_t *ifp;
    int     new_size;
    int     real_size;

    if (byte_diff == 0) {
        return;
    }

    ifp = XFS_IFORK_PTR(ip, whichfork);
    new_size = (int)ifp->if_bytes + byte_diff;
    ASSERT(new_size >= 0);

    if (new_size == 0) {
        if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
            kmem_free(ifp->if_u1.if_data);
        }
        ifp->if_u1.if_data = NULL;
        real_size = 0;
    } else if (new_size <= sizeof(ifp->if_u2.if_inline_data)) {
        /*
         * If the valid extents/data can fit in if_inline_ext/data,
         * copy them from the malloc'd vector and free it.
         */
        if (ifp->if_u1.if_data == NULL) {
            ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
        } else if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
            ASSERT(ifp->if_real_bytes != 0);
            memcpy(ifp->if_u2.if_inline_data, ifp->if_u1.if_data,
                  new_size);
            kmem_free(ifp->if_u1.if_data);
            ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
        }
        real_size = 0;
    } else {
        /*
         * Stuck with malloc/realloc.
         * For inline data, the underlying buffer must be
         * a multiple of 4 bytes in size so that it can be
         * logged and stay on word boundaries.  We enforce
         * that here.
         */
        real_size = roundup(new_size, 4);
        if (ifp->if_u1.if_data == NULL) {
            ASSERT(ifp->if_real_bytes == 0);
            ifp->if_u1.if_data = kmem_alloc(real_size,
                            KM_SLEEP | KM_NOFS);
        } else if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
            /*
             * Only do the realloc if the underlying size
             * is really changing.
             */
            if (ifp->if_real_bytes != real_size) {
                ifp->if_u1.if_data =
                    kmem_realloc(ifp->if_u1.if_data,
                            real_size,
                            ifp->if_real_bytes,
                            KM_SLEEP | KM_NOFS);
            }
        } else {
            ASSERT(ifp->if_real_bytes == 0);
            ifp->if_u1.if_data = kmem_alloc(real_size,
                            KM_SLEEP | KM_NOFS);
            memcpy(ifp->if_u1.if_data, ifp->if_u2.if_inline_data,
                ifp->if_bytes);
        }
    }
    ifp->if_real_bytes = real_size;
    ifp->if_bytes = new_size;
    ASSERT(ifp->if_bytes <= XFS_IFORK_SIZE(ip, whichfork));
}

void
xfs_idestroy_fork(
    xfs_inode_t *ip,
    int     whichfork)
{
    xfs_ifork_t *ifp;

    ifp = XFS_IFORK_PTR(ip, whichfork);
    if (ifp->if_broot != NULL) {
        kmem_free(ifp->if_broot);
        ifp->if_broot = NULL;
    }

    /*
     * If the format is local, then we can't have an extents
     * array so just look for an inline data array.  If we're
     * not local then we may or may not have an extents list,
     * so check and free it up if we do.
     */
    if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
        if ((ifp->if_u1.if_data != ifp->if_u2.if_inline_data) &&
            (ifp->if_u1.if_data != NULL)) {
            ASSERT(ifp->if_real_bytes != 0);
            kmem_free(ifp->if_u1.if_data);
            ifp->if_u1.if_data = NULL;
            ifp->if_real_bytes = 0;
        }
    } else if ((ifp->if_flags & XFS_IFEXTENTS) &&
           ((ifp->if_flags & XFS_IFEXTIREC) ||
            ((ifp->if_u1.if_extents != NULL) &&
             (ifp->if_u1.if_extents != ifp->if_u2.if_inline_ext)))) {
        ASSERT(ifp->if_real_bytes != 0);
        xfs_iext_destroy(ifp);
    }
    ASSERT(ifp->if_u1.if_extents == NULL ||
           ifp->if_u1.if_extents == ifp->if_u2.if_inline_ext);
    ASSERT(ifp->if_real_bytes == 0);
    if (whichfork == XFS_ATTR_FORK) {
        kmem_zone_free(xfs_ifork_zone, ip->i_afp);
        ip->i_afp = NULL;
    }
}

/*
 * This is called to unpin an inode.  The caller must have the inode locked
 * in at least shared mode so that the buffer cannot be subsequently pinned
 * once someone is waiting for it to be unpinned.
 */
static void
xfs_iunpin(
    struct xfs_inode    *ip)
{
    ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));

    trace_xfs_inode_unpin_nowait(ip, _RET_IP_);

    /* Give the log a push to start the unpinning I/O */
    xfs_log_force_lsn(ip->i_mount, ip->i_itemp->ili_last_lsn, 0);

}

static void
__xfs_iunpin_wait(
    struct xfs_inode    *ip)
{
    wait_queue_head_t *wq = bit_waitqueue(&ip->i_flags, __XFS_IPINNED_BIT);
    DEFINE_WAIT_BIT(wait, &ip->i_flags, __XFS_IPINNED_BIT);

    xfs_iunpin(ip);

    do {
        prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
        if (xfs_ipincount(ip))
            io_schedule();
    } while (xfs_ipincount(ip));
    finish_wait(wq, &wait.wait);
}

void
xfs_iunpin_wait(
    struct xfs_inode    *ip)
{
    if (xfs_ipincount(ip))
        __xfs_iunpin_wait(ip);
}

/*
 * xfs_iextents_copy()
 *
 * This is called to copy the REAL extents (as opposed to the delayed
 * allocation extents) from the inode into the given buffer.  It
 * returns the number of bytes copied into the buffer.
 *
 * If there are no delayed allocation extents, then we can just
 * memcpy() the extents into the buffer.  Otherwise, we need to
 * examine each extent in turn and skip those which are delayed.
 */
int
xfs_iextents_copy(
    xfs_inode_t     *ip,
    xfs_bmbt_rec_t      *dp,
    int         whichfork)
{
    int         copied;
    int         i;
    xfs_ifork_t     *ifp;
    int         nrecs;
    xfs_fsblock_t       start_block;

    ifp = XFS_IFORK_PTR(ip, whichfork);
    ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
    ASSERT(ifp->if_bytes > 0);

    nrecs = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
    XFS_BMAP_TRACE_EXLIST(ip, nrecs, whichfork);
    ASSERT(nrecs > 0);

    /*
     * There are some delayed allocation extents in the
     * inode, so copy the extents one at a time and skip
     * the delayed ones.  There must be at least one
     * non-delayed extent.
     */
    copied = 0;
    for (i = 0; i < nrecs; i++) {
        xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, i);
        start_block = xfs_bmbt_get_startblock(ep);
        if (isnullstartblock(start_block)) {
            /*
             * It's a delayed allocation extent, so skip it.
             */
            continue;
        }

        /* Translate to on disk format */
        put_unaligned(cpu_to_be64(ep->l0), &dp->l0);
        put_unaligned(cpu_to_be64(ep->l1), &dp->l1);
        dp++;
        copied++;
    }
    ASSERT(copied != 0);
    xfs_validate_extents(ifp, copied, XFS_EXTFMT_INODE(ip));

    return (copied * (uint)sizeof(xfs_bmbt_rec_t));
}

/*
 * Each of the following cases stores data into the same region
 * of the on-disk inode, so only one of them can be valid at
 * any given time. While it is possible to have conflicting formats
 * and log flags, e.g. having XFS_ILOG_?DATA set when the fork is
 * in EXTENTS format, this can only happen when the fork has
 * changed formats after being modified but before being flushed.
 * In these cases, the format always takes precedence, because the
 * format indicates the current state of the fork.
 */
/*ARGSUSED*/
STATIC void
xfs_iflush_fork(
    xfs_inode_t     *ip,
    xfs_dinode_t        *dip,
    xfs_inode_log_item_t    *iip,
    int         whichfork,
    xfs_buf_t       *bp)
{
    char            *cp;
    xfs_ifork_t     *ifp;
    xfs_mount_t     *mp;
#ifdef XFS_TRANS_DEBUG
    int         first;
#endif
    static const short  brootflag[2] =
        { XFS_ILOG_DBROOT, XFS_ILOG_ABROOT };
    static const short  dataflag[2] =
        { XFS_ILOG_DDATA, XFS_ILOG_ADATA };
    static const short  extflag[2] =
        { XFS_ILOG_DEXT, XFS_ILOG_AEXT };

    if (!iip)
        return;
    ifp = XFS_IFORK_PTR(ip, whichfork);
    /*
     * This can happen if we gave up in iformat in an error path,
     * for the attribute fork.
     */
    if (!ifp) {
        ASSERT(whichfork == XFS_ATTR_FORK);
        return;
    }
    cp = XFS_DFORK_PTR(dip, whichfork);
    mp = ip->i_mount;
    switch (XFS_IFORK_FORMAT(ip, whichfork)) {
    case XFS_DINODE_FMT_LOCAL:
        if ((iip->ili_fields & dataflag[whichfork]) &&
            (ifp->if_bytes > 0)) {
            ASSERT(ifp->if_u1.if_data != NULL);
            ASSERT(ifp->if_bytes <= XFS_IFORK_SIZE(ip, whichfork));
            memcpy(cp, ifp->if_u1.if_data, ifp->if_bytes);
        }
        break;

    case XFS_DINODE_FMT_EXTENTS:
        ASSERT((ifp->if_flags & XFS_IFEXTENTS) ||
               !(iip->ili_fields & extflag[whichfork]));
        if ((iip->ili_fields & extflag[whichfork]) &&
            (ifp->if_bytes > 0)) {
            ASSERT(xfs_iext_get_ext(ifp, 0));
            ASSERT(XFS_IFORK_NEXTENTS(ip, whichfork) > 0);
            (void)xfs_iextents_copy(ip, (xfs_bmbt_rec_t *)cp,
                whichfork);
        }
        break;

    case XFS_DINODE_FMT_BTREE:
        if ((iip->ili_fields & brootflag[whichfork]) &&
            (ifp->if_broot_bytes > 0)) {
            ASSERT(ifp->if_broot != NULL);
            ASSERT(ifp->if_broot_bytes <=
                   (XFS_IFORK_SIZE(ip, whichfork) +
                XFS_BROOT_SIZE_ADJ));
            xfs_bmbt_to_bmdr(mp, ifp->if_broot, ifp->if_broot_bytes,
                (xfs_bmdr_block_t *)cp,
                XFS_DFORK_SIZE(dip, mp, whichfork));
        }
        break;

    case XFS_DINODE_FMT_DEV:
        if (iip->ili_fields & XFS_ILOG_DEV) {
            ASSERT(whichfork == XFS_DATA_FORK);
            xfs_dinode_put_rdev(dip, ip->i_df.if_u2.if_rdev);
        }
        break;

    case XFS_DINODE_FMT_UUID:
        if (iip->ili_fields & XFS_ILOG_UUID) {
            ASSERT(whichfork == XFS_DATA_FORK);
            memcpy(XFS_DFORK_DPTR(dip),
                   &ip->i_df.if_u2.if_uuid,
                   sizeof(uuid_t));
        }
        break;

    default:
        ASSERT(0);
        break;
    }
}

STATIC int
xfs_iflush_cluster(
    xfs_inode_t *ip,
    xfs_buf_t   *bp)
{
    xfs_mount_t     *mp = ip->i_mount;
    struct xfs_perag    *pag;
    unsigned long       first_index, mask;
    unsigned long       inodes_per_cluster;
    int         ilist_size;
    xfs_inode_t     **ilist;
    xfs_inode_t     *iq;
    int         nr_found;
    int         clcount = 0;
    int         bufwasdelwri;
    int         i;

    pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));

    inodes_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog;
    ilist_size = inodes_per_cluster * sizeof(xfs_inode_t *);
    ilist = kmem_alloc(ilist_size, KM_MAYFAIL|KM_NOFS);
    if (!ilist)
        goto out_put;

    mask = ~(((XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog)) - 1);
    first_index = XFS_INO_TO_AGINO(mp, ip->i_ino) & mask;
    rcu_read_lock();
    /* really need a gang lookup range call here */
    nr_found = radix_tree_gang_lookup(&pag->pag_ici_root, (void**)ilist,
                    first_index, inodes_per_cluster);
    if (nr_found == 0)
        goto out_free;

    for (i = 0; i < nr_found; i++) {
        iq = ilist[i];
        if (iq == ip)
            continue;

        /*
         * because this is an RCU protected lookup, we could find a
         * recently freed or even reallocated inode during the lookup.
         * We need to check under the i_flags_lock for a valid inode
         * here. Skip it if it is not valid or the wrong inode.
         */
        spin_lock(&ip->i_flags_lock);
        if (!ip->i_ino ||
            (XFS_INO_TO_AGINO(mp, iq->i_ino) & mask) != first_index) {
            spin_unlock(&ip->i_flags_lock);
            continue;
        }
        spin_unlock(&ip->i_flags_lock);

        /*
         * Do an un-protected check to see if the inode is dirty and
         * is a candidate for flushing.  These checks will be repeated
         * later after the appropriate locks are acquired.
         */
        if (xfs_inode_clean(iq) && xfs_ipincount(iq) == 0)
            continue;

        /*
         * Try to get locks.  If any are unavailable or it is pinned,
         * then this inode cannot be flushed and is skipped.
         */

        if (!xfs_ilock_nowait(iq, XFS_ILOCK_SHARED))
            continue;
        if (!xfs_iflock_nowait(iq)) {
            xfs_iunlock(iq, XFS_ILOCK_SHARED);
            continue;
        }
        if (xfs_ipincount(iq)) {
            xfs_ifunlock(iq);
            xfs_iunlock(iq, XFS_ILOCK_SHARED);
            continue;
        }

        /*
         * arriving here means that this inode can be flushed.  First
         * re-check that it's dirty before flushing.
         */
        if (!xfs_inode_clean(iq)) {
            int error;
            error = xfs_iflush_int(iq, bp);
            if (error) {
                xfs_iunlock(iq, XFS_ILOCK_SHARED);
                goto cluster_corrupt_out;
            }
            clcount++;
        } else {
            xfs_ifunlock(iq);
        }
        xfs_iunlock(iq, XFS_ILOCK_SHARED);
    }

    if (clcount) {
        XFS_STATS_INC(xs_icluster_flushcnt);
        XFS_STATS_ADD(xs_icluster_flushinode, clcount);
    }

out_free:
    rcu_read_unlock();
    kmem_free(ilist);
out_put:
    xfs_perag_put(pag);
    return 0;


cluster_corrupt_out:
    /*
     * Corruption detected in the clustering loop.  Invalidate the
     * inode buffer and shut down the filesystem.
     */
    rcu_read_unlock();
    /*
     * Clean up the buffer.  If it was delwri, just release it --
     * brelse can handle it with no problems.  If not, shut down the
     * filesystem before releasing the buffer.
     */
    bufwasdelwri = (bp->b_flags & _XBF_DELWRI_Q);
    if (bufwasdelwri)
        xfs_buf_relse(bp);

    xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);

    if (!bufwasdelwri) {
        /*
         * Just like incore_relse: if we have b_iodone functions,
         * mark the buffer as an error and call them.  Otherwise
         * mark it as stale and brelse.
         */
        if (bp->b_iodone) {
            XFS_BUF_UNDONE(bp);
            xfs_buf_stale(bp);
            xfs_buf_ioerror(bp, EIO);
            xfs_buf_ioend(bp, 0);
        } else {
            xfs_buf_stale(bp);
            xfs_buf_relse(bp);
        }
    }

    /*
     * Unlocks the flush lock
     */
    xfs_iflush_abort(iq, false);
    kmem_free(ilist);
    xfs_perag_put(pag);
    return XFS_ERROR(EFSCORRUPTED);
}

/*
 * Flush dirty inode metadata into the backing buffer.
 *
 * The caller must have the inode lock and the inode flush lock held.  The
 * inode lock will still be held upon return to the caller, and the inode
 * flush lock will be released after the inode has reached the disk.
 *
 * The caller must write out the buffer returned in *bpp and release it.
 */
int
xfs_iflush(
    struct xfs_inode    *ip,
    struct xfs_buf      **bpp)
{
    struct xfs_mount    *mp = ip->i_mount;
    struct xfs_buf      *bp;
    struct xfs_dinode   *dip;
    int         error;

    XFS_STATS_INC(xs_iflush_count);

    ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
    ASSERT(xfs_isiflocked(ip));
    ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
           ip->i_d.di_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK));

    *bpp = NULL;

    xfs_iunpin_wait(ip);

    /*
     * For stale inodes we cannot rely on the backing buffer remaining
     * stale in cache for the remaining life of the stale inode and so
     * xfs_imap_to_bp() below may give us a buffer that no longer contains
     * inodes below. We have to check this after ensuring the inode is
     * unpinned so that it is safe to reclaim the stale inode after the
     * flush call.
     */
    if (xfs_iflags_test(ip, XFS_ISTALE)) {
        xfs_ifunlock(ip);
        return 0;
    }

    /*
     * This may have been unpinned because the filesystem is shutting
     * down forcibly. If that's the case we must not write this inode
     * to disk, because the log record didn't make it to disk.
     *
     * We also have to remove the log item from the AIL in this case,
     * as we wait for an empty AIL as part of the unmount process.
     */
    if (XFS_FORCED_SHUTDOWN(mp)) {
        error = XFS_ERROR(EIO);
        goto abort_out;
    }

    /*
     * Get the buffer containing the on-disk inode.
     */
    error = xfs_imap_to_bp(mp, NULL, &ip->i_imap, &dip, &bp, XBF_TRYLOCK,
                   0);
    if (error || !bp) {
        xfs_ifunlock(ip);
        return error;
    }

    /*
     * First flush out the inode that xfs_iflush was called with.
     */
    error = xfs_iflush_int(ip, bp);
    if (error)
        goto corrupt_out;

    /*
     * If the buffer is pinned then push on the log now so we won't
     * get stuck waiting in the write for too long.
     */
    if (xfs_buf_ispinned(bp))
        xfs_log_force(mp, 0);

    /*
     * inode clustering:
     * see if other inodes can be gathered into this write
     */
    error = xfs_iflush_cluster(ip, bp);
    if (error)
        goto cluster_corrupt_out;

    *bpp = bp;
    return 0;

corrupt_out:
    xfs_buf_relse(bp);
    xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
cluster_corrupt_out:
    error = XFS_ERROR(EFSCORRUPTED);
abort_out:
    /*
     * Unlocks the flush lock
     */
    xfs_iflush_abort(ip, false);
    return error;
}


STATIC int
xfs_iflush_int(
    xfs_inode_t     *ip,
    xfs_buf_t       *bp)
{
    xfs_inode_log_item_t    *iip;
    xfs_dinode_t        *dip;
    xfs_mount_t     *mp;
#ifdef XFS_TRANS_DEBUG
    int         first;
#endif

    ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
    ASSERT(xfs_isiflocked(ip));
    ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
           ip->i_d.di_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK));

    iip = ip->i_itemp;
    mp = ip->i_mount;

    /* set *dip = inode's place in the buffer */
    dip = (xfs_dinode_t *)xfs_buf_offset(bp, ip->i_imap.im_boffset);

    if (XFS_TEST_ERROR(dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC),
                   mp, XFS_ERRTAG_IFLUSH_1, XFS_RANDOM_IFLUSH_1)) {
        xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
            "%s: Bad inode %Lu magic number 0x%x, ptr 0x%p",
            __func__, ip->i_ino, be16_to_cpu(dip->di_magic), dip);
        goto corrupt_out;
    }
    if (XFS_TEST_ERROR(ip->i_d.di_magic != XFS_DINODE_MAGIC,
                mp, XFS_ERRTAG_IFLUSH_2, XFS_RANDOM_IFLUSH_2)) {
        xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
            "%s: Bad inode %Lu, ptr 0x%p, magic number 0x%x",
            __func__, ip->i_ino, ip, ip->i_d.di_magic);
        goto corrupt_out;
    }
    if (S_ISREG(ip->i_d.di_mode)) {
        if (XFS_TEST_ERROR(
            (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS) &&
            (ip->i_d.di_format != XFS_DINODE_FMT_BTREE),
            mp, XFS_ERRTAG_IFLUSH_3, XFS_RANDOM_IFLUSH_3)) {
            xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
                "%s: Bad regular inode %Lu, ptr 0x%p",
                __func__, ip->i_ino, ip);
            goto corrupt_out;
        }
    } else if (S_ISDIR(ip->i_d.di_mode)) {
        if (XFS_TEST_ERROR(
            (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS) &&
            (ip->i_d.di_format != XFS_DINODE_FMT_BTREE) &&
            (ip->i_d.di_format != XFS_DINODE_FMT_LOCAL),
            mp, XFS_ERRTAG_IFLUSH_4, XFS_RANDOM_IFLUSH_4)) {
            xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
                "%s: Bad directory inode %Lu, ptr 0x%p",
                __func__, ip->i_ino, ip);
            goto corrupt_out;
        }
    }
    if (XFS_TEST_ERROR(ip->i_d.di_nextents + ip->i_d.di_anextents >
                ip->i_d.di_nblocks, mp, XFS_ERRTAG_IFLUSH_5,
                XFS_RANDOM_IFLUSH_5)) {
        xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
            "%s: detected corrupt incore inode %Lu, "
            "total extents = %d, nblocks = %Ld, ptr 0x%p",
            __func__, ip->i_ino,
            ip->i_d.di_nextents + ip->i_d.di_anextents,
            ip->i_d.di_nblocks, ip);
        goto corrupt_out;
    }
    if (XFS_TEST_ERROR(ip->i_d.di_forkoff > mp->m_sb.sb_inodesize,
                mp, XFS_ERRTAG_IFLUSH_6, XFS_RANDOM_IFLUSH_6)) {
        xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
            "%s: bad inode %Lu, forkoff 0x%x, ptr 0x%p",
            __func__, ip->i_ino, ip->i_d.di_forkoff, ip);
        goto corrupt_out;
    }
    /*
     * bump the flush iteration count, used to detect flushes which
     * postdate a log record during recovery.
     */

    ip->i_d.di_flushiter++;

    /*
     * Copy the dirty parts of the inode into the on-disk
     * inode.  We always copy out the core of the inode,
     * because if the inode is dirty at all the core must
     * be.
     */
    xfs_dinode_to_disk(dip, &ip->i_d);

    /* Wrap, we never let the log put out DI_MAX_FLUSH */
    if (ip->i_d.di_flushiter == DI_MAX_FLUSH)
        ip->i_d.di_flushiter = 0;

    /*
     * If this is really an old format inode and the superblock version
     * has not been updated to support only new format inodes, then
     * convert back to the old inode format.  If the superblock version
     * has been updated, then make the conversion permanent.
     */
    ASSERT(ip->i_d.di_version == 1 || xfs_sb_version_hasnlink(&mp->m_sb));
    if (ip->i_d.di_version == 1) {
        if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
            /*
             * Convert it back.
             */
            ASSERT(ip->i_d.di_nlink <= XFS_MAXLINK_1);
            dip->di_onlink = cpu_to_be16(ip->i_d.di_nlink);
        } else {
            /*
             * The superblock version has already been bumped,
             * so just make the conversion to the new inode
             * format permanent.
             */
            ip->i_d.di_version = 2;
            dip->di_version = 2;
            ip->i_d.di_onlink = 0;
            dip->di_onlink = 0;
            memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
            memset(&(dip->di_pad[0]), 0,
                  sizeof(dip->di_pad));
            ASSERT(xfs_get_projid(ip) == 0);
        }
    }

    xfs_iflush_fork(ip, dip, iip, XFS_DATA_FORK, bp);
    if (XFS_IFORK_Q(ip))
        xfs_iflush_fork(ip, dip, iip, XFS_ATTR_FORK, bp);
    xfs_inobp_check(mp, bp);

    /*
     * We've recorded everything logged in the inode, so we'd like to clear
     * the ili_fields bits so we don't log and flush things unnecessarily.
     * However, we can't stop logging all this information until the data
     * we've copied into the disk buffer is written to disk.  If we did we
     * might overwrite the copy of the inode in the log with all the data
     * after re-logging only part of it, and in the face of a crash we
     * wouldn't have all the data we need to recover.
     *
     * What we do is move the bits to the ili_last_fields field.  When
     * logging the inode, these bits are moved back to the ili_fields field.
     * In the xfs_iflush_done() routine we clear ili_last_fields, since we
     * know that the information those bits represent is permanently on
     * disk.  As long as the flush completes before the inode is logged
     * again, then both ili_fields and ili_last_fields will be cleared.
     *
     * We can play with the ili_fields bits here, because the inode lock
     * must be held exclusively in order to set bits there and the flush
     * lock protects the ili_last_fields bits.  Set ili_logged so the flush
     * done routine can tell whether or not to look in the AIL.  Also, store
     * the current LSN of the inode so that we can tell whether the item has
     * moved in the AIL from xfs_iflush_done().  In order to read the lsn we
     * need the AIL lock, because it is a 64 bit value that cannot be read
     * atomically.
     */
    if (iip != NULL && iip->ili_fields != 0) {
        iip->ili_last_fields = iip->ili_fields;
        iip->ili_fields = 0;
        iip->ili_logged = 1;

        xfs_trans_ail_copy_lsn(mp->m_ail, &iip->ili_flush_lsn,
                    &iip->ili_item.li_lsn);

        /*
         * Attach the function xfs_iflush_done to the inode's
         * buffer.  This will remove the inode from the AIL
         * and unlock the inode's flush lock when the inode is
         * completely written to disk.
         */
        xfs_buf_attach_iodone(bp, xfs_iflush_done, &iip->ili_item);

        ASSERT(bp->b_fspriv != NULL);
        ASSERT(bp->b_iodone != NULL);
    } else {
        /*
         * We're flushing an inode which is not in the AIL and has
         * not been logged.  For this case we can immediately drop
         * the inode flush lock because we can avoid the whole
         * AIL state thing.  It's OK to drop the flush lock now,
         * because we've already locked the buffer and to do anything
         * you really need both.
         */
        if (iip != NULL) {
            ASSERT(iip->ili_logged == 0);
            ASSERT(iip->ili_last_fields == 0);
            ASSERT((iip->ili_item.li_flags & XFS_LI_IN_AIL) == 0);
        }
        xfs_ifunlock(ip);
    }

    return 0;

corrupt_out:
    return XFS_ERROR(EFSCORRUPTED);
}

/*
 * Return a pointer to the extent record at file index idx.
 */
xfs_bmbt_rec_host_t *
xfs_iext_get_ext(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    xfs_extnum_t    idx)        /* index of target extent */
{
    ASSERT(idx >= 0);
    ASSERT(idx < ifp->if_bytes / sizeof(xfs_bmbt_rec_t));

    if ((ifp->if_flags & XFS_IFEXTIREC) && (idx == 0)) {
        return ifp->if_u1.if_ext_irec->er_extbuf;
    } else if (ifp->if_flags & XFS_IFEXTIREC) {
        xfs_ext_irec_t  *erp;       /* irec pointer */
        int     erp_idx = 0;    /* irec index */
        xfs_extnum_t    page_idx = idx; /* ext index in target list */

        erp = xfs_iext_idx_to_irec(ifp, &page_idx, &erp_idx, 0);
        return &erp->er_extbuf[page_idx];
    } else if (ifp->if_bytes) {
        return &ifp->if_u1.if_extents[idx];
    } else {
        return NULL;
    }
}

/*
 * Insert new item(s) into the extent records for incore inode
 * fork 'ifp'.  'count' new items are inserted at index 'idx'.
 */
void
xfs_iext_insert(
    xfs_inode_t *ip,        /* incore inode pointer */
    xfs_extnum_t    idx,        /* starting index of new items */
    xfs_extnum_t    count,      /* number of inserted items */
    xfs_bmbt_irec_t *new,       /* items to insert */
    int     state)      /* type of extent conversion */
{
    xfs_ifork_t *ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df;
    xfs_extnum_t    i;      /* extent record index */

    trace_xfs_iext_insert(ip, idx, new, state, _RET_IP_);

    ASSERT(ifp->if_flags & XFS_IFEXTENTS);
    xfs_iext_add(ifp, idx, count);
    for (i = idx; i < idx + count; i++, new++)
        xfs_bmbt_set_all(xfs_iext_get_ext(ifp, i), new);
}

/*
 * This is called when the amount of space required for incore file
 * extents needs to be increased. The ext_diff parameter stores the
 * number of new extents being added and the idx parameter contains
 * the extent index where the new extents will be added. If the new
 * extents are being appended, then we just need to (re)allocate and
 * initialize the space. Otherwise, if the new extents are being
 * inserted into the middle of the existing entries, a bit more work
 * is required to make room for the new extents to be inserted. The
 * caller is responsible for filling in the new extent entries upon
 * return.
 */
void
xfs_iext_add(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    xfs_extnum_t    idx,        /* index to begin adding exts */
    int     ext_diff)   /* number of extents to add */
{
    int     byte_diff;  /* new bytes being added */
    int     new_size;   /* size of extents after adding */
    xfs_extnum_t    nextents;   /* number of extents in file */

    nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
    ASSERT((idx >= 0) && (idx <= nextents));
    byte_diff = ext_diff * sizeof(xfs_bmbt_rec_t);
    new_size = ifp->if_bytes + byte_diff;
    /*
     * If the new number of extents (nextents + ext_diff)
     * fits inside the inode, then continue to use the inline
     * extent buffer.
     */
    if (nextents + ext_diff <= XFS_INLINE_EXTS) {
        if (idx < nextents) {
            memmove(&ifp->if_u2.if_inline_ext[idx + ext_diff],
                &ifp->if_u2.if_inline_ext[idx],
                (nextents - idx) * sizeof(xfs_bmbt_rec_t));
            memset(&ifp->if_u2.if_inline_ext[idx], 0, byte_diff);
        }
        ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
        ifp->if_real_bytes = 0;
    }
    /*
     * Otherwise use a linear (direct) extent list.
     * If the extents are currently inside the inode,
     * xfs_iext_realloc_direct will switch us from
     * inline to direct extent allocation mode.
     */
    else if (nextents + ext_diff <= XFS_LINEAR_EXTS) {
        xfs_iext_realloc_direct(ifp, new_size);
        if (idx < nextents) {
            memmove(&ifp->if_u1.if_extents[idx + ext_diff],
                &ifp->if_u1.if_extents[idx],
                (nextents - idx) * sizeof(xfs_bmbt_rec_t));
            memset(&ifp->if_u1.if_extents[idx], 0, byte_diff);
        }
    }
    /* Indirection array */
    else {
        xfs_ext_irec_t  *erp;
        int     erp_idx = 0;
        int     page_idx = idx;

        ASSERT(nextents + ext_diff > XFS_LINEAR_EXTS);
        if (ifp->if_flags & XFS_IFEXTIREC) {
            erp = xfs_iext_idx_to_irec(ifp, &page_idx, &erp_idx, 1);
        } else {
            xfs_iext_irec_init(ifp);
            ASSERT(ifp->if_flags & XFS_IFEXTIREC);
            erp = ifp->if_u1.if_ext_irec;
        }
        /* Extents fit in target extent page */
        if (erp && erp->er_extcount + ext_diff <= XFS_LINEAR_EXTS) {
            if (page_idx < erp->er_extcount) {
                memmove(&erp->er_extbuf[page_idx + ext_diff],
                    &erp->er_extbuf[page_idx],
                    (erp->er_extcount - page_idx) *
                    sizeof(xfs_bmbt_rec_t));
                memset(&erp->er_extbuf[page_idx], 0, byte_diff);
            }
            erp->er_extcount += ext_diff;
            xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
        }
        /* Insert a new extent page */
        else if (erp) {
            xfs_iext_add_indirect_multi(ifp,
                erp_idx, page_idx, ext_diff);
        }
        /*
         * If extent(s) are being appended to the last page in
         * the indirection array and the new extent(s) don't fit
         * in the page, then erp is NULL and erp_idx is set to
         * the next index needed in the indirection array.
         */
        else {
            int count = ext_diff;

            while (count) {
                erp = xfs_iext_irec_new(ifp, erp_idx);
                erp->er_extcount = count;
                count -= MIN(count, (int)XFS_LINEAR_EXTS);
                if (count) {
                    erp_idx++;
                }
            }
        }
    }
    ifp->if_bytes = new_size;
}

/*
 * This is called when incore extents are being added to the indirection
 * array and the new extents do not fit in the target extent list. The
 * erp_idx parameter contains the irec index for the target extent list
 * in the indirection array, and the idx parameter contains the extent
 * index within the list. The number of extents being added is stored
 * in the count parameter.
 *
 *    |-------|   |-------|
 *    |       |   |       |    idx - number of extents before idx
 *    |  idx  |   | count |
 *    |       |   |       |    count - number of extents being inserted at idx
 *    |-------|   |-------|
 *    | count |   | nex2  |    nex2 - number of extents after idx + count
 *    |-------|   |-------|
 */
void
xfs_iext_add_indirect_multi(
    xfs_ifork_t *ifp,           /* inode fork pointer */
    int     erp_idx,        /* target extent irec index */
    xfs_extnum_t    idx,            /* index within target list */
    int     count)          /* new extents being added */
{
    int     byte_diff;      /* new bytes being added */
    xfs_ext_irec_t  *erp;           /* pointer to irec entry */
    xfs_extnum_t    ext_diff;       /* number of extents to add */
    xfs_extnum_t    ext_cnt;        /* new extents still needed */
    xfs_extnum_t    nex2;           /* extents after idx + count */
    xfs_bmbt_rec_t  *nex2_ep = NULL;    /* temp list for nex2 extents */
    int     nlists;         /* number of irec's (lists) */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    erp = &ifp->if_u1.if_ext_irec[erp_idx];
    nex2 = erp->er_extcount - idx;
    nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;

    /*
     * Save second part of target extent list
     * (all extents past */
    if (nex2) {
        byte_diff = nex2 * sizeof(xfs_bmbt_rec_t);
        nex2_ep = (xfs_bmbt_rec_t *) kmem_alloc(byte_diff, KM_NOFS);
        memmove(nex2_ep, &erp->er_extbuf[idx], byte_diff);
        erp->er_extcount -= nex2;
        xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, -nex2);
        memset(&erp->er_extbuf[idx], 0, byte_diff);
    }

    /*
     * Add the new extents to the end of the target
     * list, then allocate new irec record(s) and
     * extent buffer(s) as needed to store the rest
     * of the new extents.
     */
    ext_cnt = count;
    ext_diff = MIN(ext_cnt, (int)XFS_LINEAR_EXTS - erp->er_extcount);
    if (ext_diff) {
        erp->er_extcount += ext_diff;
        xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
        ext_cnt -= ext_diff;
    }
    while (ext_cnt) {
        erp_idx++;
        erp = xfs_iext_irec_new(ifp, erp_idx);
        ext_diff = MIN(ext_cnt, (int)XFS_LINEAR_EXTS);
        erp->er_extcount = ext_diff;
        xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
        ext_cnt -= ext_diff;
    }

    /* Add nex2 extents back to indirection array */
    if (nex2) {
        xfs_extnum_t    ext_avail;
        int     i;

        byte_diff = nex2 * sizeof(xfs_bmbt_rec_t);
        ext_avail = XFS_LINEAR_EXTS - erp->er_extcount;
        i = 0;
        /*
         * If nex2 extents fit in the current page, append
         * nex2_ep after the new extents.
         */
        if (nex2 <= ext_avail) {
            i = erp->er_extcount;
        }
        /*
         * Otherwise, check if space is available in the
         * next page.
         */
        else if ((erp_idx < nlists - 1) &&
             (nex2 <= (ext_avail = XFS_LINEAR_EXTS -
              ifp->if_u1.if_ext_irec[erp_idx+1].er_extcount))) {
            erp_idx++;
            erp++;
            /* Create a hole for nex2 extents */
            memmove(&erp->er_extbuf[nex2], erp->er_extbuf,
                erp->er_extcount * sizeof(xfs_bmbt_rec_t));
        }
        /*
         * Final choice, create a new extent page for
         * nex2 extents.
         */
        else {
            erp_idx++;
            erp = xfs_iext_irec_new(ifp, erp_idx);
        }
        memmove(&erp->er_extbuf[i], nex2_ep, byte_diff);
        kmem_free(nex2_ep);
        erp->er_extcount += nex2;
        xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, nex2);
    }
}

/*
 * This is called when the amount of space required for incore file
 * extents needs to be decreased. The ext_diff parameter stores the
 * number of extents to be removed and the idx parameter contains
 * the extent index where the extents will be removed from.
 *
 * If the amount of space needed has decreased below the linear
 * limit, XFS_IEXT_BUFSZ, then switch to using the contiguous
 * extent array.  Otherwise, use kmem_realloc() to adjust the
 * size to what is needed.
 */
void
xfs_iext_remove(
    xfs_inode_t *ip,        /* incore inode pointer */
    xfs_extnum_t    idx,        /* index to begin removing exts */
    int     ext_diff,   /* number of extents to remove */
    int     state)      /* type of extent conversion */
{
    xfs_ifork_t *ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df;
    xfs_extnum_t    nextents;   /* number of extents in file */
    int     new_size;   /* size of extents after removal */

    trace_xfs_iext_remove(ip, idx, state, _RET_IP_);

    ASSERT(ext_diff > 0);
    nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
    new_size = (nextents - ext_diff) * sizeof(xfs_bmbt_rec_t);

    if (new_size == 0) {
        xfs_iext_destroy(ifp);
    } else if (ifp->if_flags & XFS_IFEXTIREC) {
        xfs_iext_remove_indirect(ifp, idx, ext_diff);
    } else if (ifp->if_real_bytes) {
        xfs_iext_remove_direct(ifp, idx, ext_diff);
    } else {
        xfs_iext_remove_inline(ifp, idx, ext_diff);
    }
    ifp->if_bytes = new_size;
}

/*
 * This removes ext_diff extents from the inline buffer, beginning
 * at extent index idx.
 */
void
xfs_iext_remove_inline(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    xfs_extnum_t    idx,        /* index to begin removing exts */
    int     ext_diff)   /* number of extents to remove */
{
    int     nextents;   /* number of extents in file */

    ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
    ASSERT(idx < XFS_INLINE_EXTS);
    nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
    ASSERT(((nextents - ext_diff) > 0) &&
        (nextents - ext_diff) < XFS_INLINE_EXTS);

    if (idx + ext_diff < nextents) {
        memmove(&ifp->if_u2.if_inline_ext[idx],
            &ifp->if_u2.if_inline_ext[idx + ext_diff],
            (nextents - (idx + ext_diff)) *
             sizeof(xfs_bmbt_rec_t));
        memset(&ifp->if_u2.if_inline_ext[nextents - ext_diff],
            0, ext_diff * sizeof(xfs_bmbt_rec_t));
    } else {
        memset(&ifp->if_u2.if_inline_ext[idx], 0,
            ext_diff * sizeof(xfs_bmbt_rec_t));
    }
}

/*
 * This removes ext_diff extents from a linear (direct) extent list,
 * beginning at extent index idx. If the extents are being removed
 * from the end of the list (ie. truncate) then we just need to re-
 * allocate the list to remove the extra space. Otherwise, if the
 * extents are being removed from the middle of the existing extent
 * entries, then we first need to move the extent records beginning
 * at idx + ext_diff up in the list to overwrite the records being
 * removed, then remove the extra space via kmem_realloc.
 */
void
xfs_iext_remove_direct(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    xfs_extnum_t    idx,        /* index to begin removing exts */
    int     ext_diff)   /* number of extents to remove */
{
    xfs_extnum_t    nextents;   /* number of extents in file */
    int     new_size;   /* size of extents after removal */

    ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
    new_size = ifp->if_bytes -
        (ext_diff * sizeof(xfs_bmbt_rec_t));
    nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);

    if (new_size == 0) {
        xfs_iext_destroy(ifp);
        return;
    }
    /* Move extents up in the list (if needed) */
    if (idx + ext_diff < nextents) {
        memmove(&ifp->if_u1.if_extents[idx],
            &ifp->if_u1.if_extents[idx + ext_diff],
            (nextents - (idx + ext_diff)) *
             sizeof(xfs_bmbt_rec_t));
    }
    memset(&ifp->if_u1.if_extents[nextents - ext_diff],
        0, ext_diff * sizeof(xfs_bmbt_rec_t));
    /*
     * Reallocate the direct extent list. If the extents
     * will fit inside the inode then xfs_iext_realloc_direct
     * will switch from direct to inline extent allocation
     * mode for us.
     */
    xfs_iext_realloc_direct(ifp, new_size);
    ifp->if_bytes = new_size;
}

/*
 * This is called when incore extents are being removed from the
 * indirection array and the extents being removed span multiple extent
 * buffers. The idx parameter contains the file extent index where we
 * want to begin removing extents, and the count parameter contains
 * how many extents need to be removed.
 *
 *    |-------|   |-------|
 *    | nex1  |   |       |    nex1 - number of extents before idx
 *    |-------|   | count |
 *    |       |   |       |    count - number of extents being removed at idx
 *    | count |   |-------|
 *    |       |   | nex2  |    nex2 - number of extents after idx + count
 *    |-------|   |-------|
 */
void
xfs_iext_remove_indirect(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    xfs_extnum_t    idx,        /* index to begin removing extents */
    int     count)      /* number of extents to remove */
{
    xfs_ext_irec_t  *erp;       /* indirection array pointer */
    int     erp_idx = 0;    /* indirection array index */
    xfs_extnum_t    ext_cnt;    /* extents left to remove */
    xfs_extnum_t    ext_diff;   /* extents to remove in current list */
    xfs_extnum_t    nex1;       /* number of extents before idx */
    xfs_extnum_t    nex2;       /* extents after idx + count */
    int     page_idx = idx; /* index in target extent list */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    erp = xfs_iext_idx_to_irec(ifp,  &page_idx, &erp_idx, 0);
    ASSERT(erp != NULL);
    nex1 = page_idx;
    ext_cnt = count;
    while (ext_cnt) {
        nex2 = MAX((erp->er_extcount - (nex1 + ext_cnt)), 0);
        ext_diff = MIN(ext_cnt, (erp->er_extcount - nex1));
        /*
         * Check for deletion of entire list;
         * xfs_iext_irec_remove() updates extent offsets.
         */
        if (ext_diff == erp->er_extcount) {
            xfs_iext_irec_remove(ifp, erp_idx);
            ext_cnt -= ext_diff;
            nex1 = 0;
            if (ext_cnt) {
                ASSERT(erp_idx < ifp->if_real_bytes /
                    XFS_IEXT_BUFSZ);
                erp = &ifp->if_u1.if_ext_irec[erp_idx];
                nex1 = 0;
                continue;
            } else {
                break;
            }
        }
        /* Move extents up (if needed) */
        if (nex2) {
            memmove(&erp->er_extbuf[nex1],
                &erp->er_extbuf[nex1 + ext_diff],
                nex2 * sizeof(xfs_bmbt_rec_t));
        }
        /* Zero out rest of page */
        memset(&erp->er_extbuf[nex1 + nex2], 0, (XFS_IEXT_BUFSZ -
            ((nex1 + nex2) * sizeof(xfs_bmbt_rec_t))));
        /* Update remaining counters */
        erp->er_extcount -= ext_diff;
        xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, -ext_diff);
        ext_cnt -= ext_diff;
        nex1 = 0;
        erp_idx++;
        erp++;
    }
    ifp->if_bytes -= count * sizeof(xfs_bmbt_rec_t);
    xfs_iext_irec_compact(ifp);
}

/*
 * Create, destroy, or resize a linear (direct) block of extents.
 */
void
xfs_iext_realloc_direct(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    int     new_size)   /* new size of extents */
{
    int     rnew_size;  /* real new size of extents */

    rnew_size = new_size;

    ASSERT(!(ifp->if_flags & XFS_IFEXTIREC) ||
        ((new_size >= 0) && (new_size <= XFS_IEXT_BUFSZ) &&
         (new_size != ifp->if_real_bytes)));

    /* Free extent records */
    if (new_size == 0) {
        xfs_iext_destroy(ifp);
    }
    /* Resize direct extent list and zero any new bytes */
    else if (ifp->if_real_bytes) {
        /* Check if extents will fit inside the inode */
        if (new_size <= XFS_INLINE_EXTS * sizeof(xfs_bmbt_rec_t)) {
            xfs_iext_direct_to_inline(ifp, new_size /
                (uint)sizeof(xfs_bmbt_rec_t));
            ifp->if_bytes = new_size;
            return;
        }
        if (!is_power_of_2(new_size)){
            rnew_size = roundup_pow_of_two(new_size);
        }
        if (rnew_size != ifp->if_real_bytes) {
            ifp->if_u1.if_extents =
                kmem_realloc(ifp->if_u1.if_extents,
                        rnew_size,
                        ifp->if_real_bytes, KM_NOFS);
        }
        if (rnew_size > ifp->if_real_bytes) {
            memset(&ifp->if_u1.if_extents[ifp->if_bytes /
                (uint)sizeof(xfs_bmbt_rec_t)], 0,
                rnew_size - ifp->if_real_bytes);
        }
    }
    /*
     * Switch from the inline extent buffer to a direct
     * extent list. Be sure to include the inline extent
     * bytes in new_size.
     */
    else {
        new_size += ifp->if_bytes;
        if (!is_power_of_2(new_size)) {
            rnew_size = roundup_pow_of_two(new_size);
        }
        xfs_iext_inline_to_direct(ifp, rnew_size);
    }
    ifp->if_real_bytes = rnew_size;
    ifp->if_bytes = new_size;
}

/*
 * Switch from linear (direct) extent records to inline buffer.
 */
void
xfs_iext_direct_to_inline(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    xfs_extnum_t    nextents)   /* number of extents in file */
{
    ASSERT(ifp->if_flags & XFS_IFEXTENTS);
    ASSERT(nextents <= XFS_INLINE_EXTS);
    /*
     * The inline buffer was zeroed when we switched
     * from inline to direct extent allocation mode,
     * so we don't need to clear it here.
     */
    memcpy(ifp->if_u2.if_inline_ext, ifp->if_u1.if_extents,
        nextents * sizeof(xfs_bmbt_rec_t));
    kmem_free(ifp->if_u1.if_extents);
    ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
    ifp->if_real_bytes = 0;
}

/*
 * Switch from inline buffer to linear (direct) extent records.
 * new_size should already be rounded up to the next power of 2
 * by the caller (when appropriate), so use new_size as it is.
 * However, since new_size may be rounded up, we can't update
 * if_bytes here. It is the caller's responsibility to update
 * if_bytes upon return.
 */
void
xfs_iext_inline_to_direct(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    int     new_size)   /* number of extents in file */
{
    ifp->if_u1.if_extents = kmem_alloc(new_size, KM_NOFS);
    memset(ifp->if_u1.if_extents, 0, new_size);
    if (ifp->if_bytes) {
        memcpy(ifp->if_u1.if_extents, ifp->if_u2.if_inline_ext,
            ifp->if_bytes);
        memset(ifp->if_u2.if_inline_ext, 0, XFS_INLINE_EXTS *
            sizeof(xfs_bmbt_rec_t));
    }
    ifp->if_real_bytes = new_size;
}

/*
 * Resize an extent indirection array to new_size bytes.
 */
STATIC void
xfs_iext_realloc_indirect(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    int     new_size)   /* new indirection array size */
{
    int     nlists;     /* number of irec's (ex lists) */
    int     size;       /* current indirection array size */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
    size = nlists * sizeof(xfs_ext_irec_t);
    ASSERT(ifp->if_real_bytes);
    ASSERT((new_size >= 0) && (new_size != size));
    if (new_size == 0) {
        xfs_iext_destroy(ifp);
    } else {
        ifp->if_u1.if_ext_irec = (xfs_ext_irec_t *)
            kmem_realloc(ifp->if_u1.if_ext_irec,
                new_size, size, KM_NOFS);
    }
}

/*
 * Switch from indirection array to linear (direct) extent allocations.
 */
STATIC void
xfs_iext_indirect_to_direct(
     xfs_ifork_t    *ifp)       /* inode fork pointer */
{
    xfs_bmbt_rec_host_t *ep;    /* extent record pointer */
    xfs_extnum_t    nextents;   /* number of extents in file */
    int     size;       /* size of file extents */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
    ASSERT(nextents <= XFS_LINEAR_EXTS);
    size = nextents * sizeof(xfs_bmbt_rec_t);

    xfs_iext_irec_compact_pages(ifp);
    ASSERT(ifp->if_real_bytes == XFS_IEXT_BUFSZ);

    ep = ifp->if_u1.if_ext_irec->er_extbuf;
    kmem_free(ifp->if_u1.if_ext_irec);
    ifp->if_flags &= ~XFS_IFEXTIREC;
    ifp->if_u1.if_extents = ep;
    ifp->if_bytes = size;
    if (nextents < XFS_LINEAR_EXTS) {
        xfs_iext_realloc_direct(ifp, size);
    }
}

/*
 * Free incore file extents.
 */
void
xfs_iext_destroy(
    xfs_ifork_t *ifp)       /* inode fork pointer */
{
    if (ifp->if_flags & XFS_IFEXTIREC) {
        int erp_idx;
        int nlists;

        nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
        for (erp_idx = nlists - 1; erp_idx >= 0 ; erp_idx--) {
            xfs_iext_irec_remove(ifp, erp_idx);
        }
        ifp->if_flags &= ~XFS_IFEXTIREC;
    } else if (ifp->if_real_bytes) {
        kmem_free(ifp->if_u1.if_extents);
    } else if (ifp->if_bytes) {
        memset(ifp->if_u2.if_inline_ext, 0, XFS_INLINE_EXTS *
            sizeof(xfs_bmbt_rec_t));
    }
    ifp->if_u1.if_extents = NULL;
    ifp->if_real_bytes = 0;
    ifp->if_bytes = 0;
}

/*
 * Return a pointer to the extent record for file system block bno.
 */
xfs_bmbt_rec_host_t *           /* pointer to found extent record */
xfs_iext_bno_to_ext(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    xfs_fileoff_t   bno,        /* block number to search for */
    xfs_extnum_t    *idxp)      /* index of target extent */
{
    xfs_bmbt_rec_host_t *base;  /* pointer to first extent */
    xfs_filblks_t   blockcount = 0; /* number of blocks in extent */
    xfs_bmbt_rec_host_t *ep = NULL; /* pointer to target extent */
    xfs_ext_irec_t  *erp = NULL;    /* indirection array pointer */
    int     high;       /* upper boundary in search */
    xfs_extnum_t    idx = 0;    /* index of target extent */
    int     low;        /* lower boundary in search */
    xfs_extnum_t    nextents;   /* number of file extents */
    xfs_fileoff_t   startoff = 0;   /* start offset of extent */

    nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
    if (nextents == 0) {
        *idxp = 0;
        return NULL;
    }
    low = 0;
    if (ifp->if_flags & XFS_IFEXTIREC) {
        /* Find target extent list */
        int erp_idx = 0;
        erp = xfs_iext_bno_to_irec(ifp, bno, &erp_idx);
        base = erp->er_extbuf;
        high = erp->er_extcount - 1;
    } else {
        base = ifp->if_u1.if_extents;
        high = nextents - 1;
    }
    /* Binary search extent records */
    while (low <= high) {
        idx = (low + high) >> 1;
        ep = base + idx;
        startoff = xfs_bmbt_get_startoff(ep);
        blockcount = xfs_bmbt_get_blockcount(ep);
        if (bno < startoff) {
            high = idx - 1;
        } else if (bno >= startoff + blockcount) {
            low = idx + 1;
        } else {
            /* Convert back to file-based extent index */
            if (ifp->if_flags & XFS_IFEXTIREC) {
                idx += erp->er_extoff;
            }
            *idxp = idx;
            return ep;
        }
    }
    /* Convert back to file-based extent index */
    if (ifp->if_flags & XFS_IFEXTIREC) {
        idx += erp->er_extoff;
    }
    if (bno >= startoff + blockcount) {
        if (++idx == nextents) {
            ep = NULL;
        } else {
            ep = xfs_iext_get_ext(ifp, idx);
        }
    }
    *idxp = idx;
    return ep;
}

/*
 * Return a pointer to the indirection array entry containing the
 * extent record for filesystem block bno. Store the index of the
 * target irec in *erp_idxp.
 */
xfs_ext_irec_t *            /* pointer to found extent record */
xfs_iext_bno_to_irec(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    xfs_fileoff_t   bno,        /* block number to search for */
    int     *erp_idxp)  /* irec index of target ext list */
{
    xfs_ext_irec_t  *erp = NULL;    /* indirection array pointer */
    xfs_ext_irec_t  *erp_next;  /* next indirection array entry */
    int     erp_idx;    /* indirection array index */
    int     nlists;     /* number of extent irec's (lists) */
    int     high;       /* binary search upper limit */
    int     low;        /* binary search lower limit */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
    erp_idx = 0;
    low = 0;
    high = nlists - 1;
    while (low <= high) {
        erp_idx = (low + high) >> 1;
        erp = &ifp->if_u1.if_ext_irec[erp_idx];
        erp_next = erp_idx < nlists - 1 ? erp + 1 : NULL;
        if (bno < xfs_bmbt_get_startoff(erp->er_extbuf)) {
            high = erp_idx - 1;
        } else if (erp_next && bno >=
               xfs_bmbt_get_startoff(erp_next->er_extbuf)) {
            low = erp_idx + 1;
        } else {
            break;
        }
    }
    *erp_idxp = erp_idx;
    return erp;
}

/*
 * Return a pointer to the indirection array entry containing the
 * extent record at file extent index *idxp. Store the index of the
 * target irec in *erp_idxp and store the page index of the target
 * extent record in *idxp.
 */
xfs_ext_irec_t *
xfs_iext_idx_to_irec(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    xfs_extnum_t    *idxp,      /* extent index (file -> page) */
    int     *erp_idxp,  /* pointer to target irec */
    int     realloc)    /* new bytes were just added */
{
    xfs_ext_irec_t  *prev;      /* pointer to previous irec */
    xfs_ext_irec_t  *erp = NULL;    /* pointer to current irec */
    int     erp_idx;    /* indirection array index */
    int     nlists;     /* number of irec's (ex lists) */
    int     high;       /* binary search upper limit */
    int     low;        /* binary search lower limit */
    xfs_extnum_t    page_idx = *idxp; /* extent index in target list */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    ASSERT(page_idx >= 0);
    ASSERT(page_idx <= ifp->if_bytes / sizeof(xfs_bmbt_rec_t));
    ASSERT(page_idx < ifp->if_bytes / sizeof(xfs_bmbt_rec_t) || realloc);

    nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
    erp_idx = 0;
    low = 0;
    high = nlists - 1;

    /* Binary search extent irec's */
    while (low <= high) {
        erp_idx = (low + high) >> 1;
        erp = &ifp->if_u1.if_ext_irec[erp_idx];
        prev = erp_idx > 0 ? erp - 1 : NULL;
        if (page_idx < erp->er_extoff || (page_idx == erp->er_extoff &&
             realloc && prev && prev->er_extcount < XFS_LINEAR_EXTS)) {
            high = erp_idx - 1;
        } else if (page_idx > erp->er_extoff + erp->er_extcount ||
               (page_idx == erp->er_extoff + erp->er_extcount &&
                !realloc)) {
            low = erp_idx + 1;
        } else if (page_idx == erp->er_extoff + erp->er_extcount &&
               erp->er_extcount == XFS_LINEAR_EXTS) {
            ASSERT(realloc);
            page_idx = 0;
            erp_idx++;
            erp = erp_idx < nlists ? erp + 1 : NULL;
            break;
        } else {
            page_idx -= erp->er_extoff;
            break;
        }
    }
    *idxp = page_idx;
    *erp_idxp = erp_idx;
    return(erp);
}

/*
 * Allocate and initialize an indirection array once the space needed
 * for incore extents increases above XFS_IEXT_BUFSZ.
 */
void
xfs_iext_irec_init(
    xfs_ifork_t *ifp)       /* inode fork pointer */
{
    xfs_ext_irec_t  *erp;       /* indirection array pointer */
    xfs_extnum_t    nextents;   /* number of extents in file */

    ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
    nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
    ASSERT(nextents <= XFS_LINEAR_EXTS);

    erp = kmem_alloc(sizeof(xfs_ext_irec_t), KM_NOFS);

    if (nextents == 0) {
        ifp->if_u1.if_extents = kmem_alloc(XFS_IEXT_BUFSZ, KM_NOFS);
    } else if (!ifp->if_real_bytes) {
        xfs_iext_inline_to_direct(ifp, XFS_IEXT_BUFSZ);
    } else if (ifp->if_real_bytes < XFS_IEXT_BUFSZ) {
        xfs_iext_realloc_direct(ifp, XFS_IEXT_BUFSZ);
    }
    erp->er_extbuf = ifp->if_u1.if_extents;
    erp->er_extcount = nextents;
    erp->er_extoff = 0;

    ifp->if_flags |= XFS_IFEXTIREC;
    ifp->if_real_bytes = XFS_IEXT_BUFSZ;
    ifp->if_bytes = nextents * sizeof(xfs_bmbt_rec_t);
    ifp->if_u1.if_ext_irec = erp;

    return;
}

/*
 * Allocate and initialize a new entry in the indirection array.
 */
xfs_ext_irec_t *
xfs_iext_irec_new(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    int     erp_idx)    /* index for new irec */
{
    xfs_ext_irec_t  *erp;       /* indirection array pointer */
    int     i;      /* loop counter */
    int     nlists;     /* number of irec's (ex lists) */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;

    /* Resize indirection array */
    xfs_iext_realloc_indirect(ifp, ++nlists *
                  sizeof(xfs_ext_irec_t));
    /*
     * Move records down in the array so the
     * new page can use erp_idx.
     */
    erp = ifp->if_u1.if_ext_irec;
    for (i = nlists - 1; i > erp_idx; i--) {
        memmove(&erp[i], &erp[i-1], sizeof(xfs_ext_irec_t));
    }
    ASSERT(i == erp_idx);

    /* Initialize new extent record */
    erp = ifp->if_u1.if_ext_irec;
    erp[erp_idx].er_extbuf = kmem_alloc(XFS_IEXT_BUFSZ, KM_NOFS);
    ifp->if_real_bytes = nlists * XFS_IEXT_BUFSZ;
    memset(erp[erp_idx].er_extbuf, 0, XFS_IEXT_BUFSZ);
    erp[erp_idx].er_extcount = 0;
    erp[erp_idx].er_extoff = erp_idx > 0 ?
        erp[erp_idx-1].er_extoff + erp[erp_idx-1].er_extcount : 0;
    return (&erp[erp_idx]);
}

/*
 * Remove a record from the indirection array.
 */
void
xfs_iext_irec_remove(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    int     erp_idx)    /* irec index to remove */
{
    xfs_ext_irec_t  *erp;       /* indirection array pointer */
    int     i;      /* loop counter */
    int     nlists;     /* number of irec's (ex lists) */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
    erp = &ifp->if_u1.if_ext_irec[erp_idx];
    if (erp->er_extbuf) {
        xfs_iext_irec_update_extoffs(ifp, erp_idx + 1,
            -erp->er_extcount);
        kmem_free(erp->er_extbuf);
    }
    /* Compact extent records */
    erp = ifp->if_u1.if_ext_irec;
    for (i = erp_idx; i < nlists - 1; i++) {
        memmove(&erp[i], &erp[i+1], sizeof(xfs_ext_irec_t));
    }
    /*
     * Manually free the last extent record from the indirection
     * array.  A call to xfs_iext_realloc_indirect() with a size
     * of zero would result in a call to xfs_iext_destroy() which
     * would in turn call this function again, creating a nasty
     * infinite loop.
     */
    if (--nlists) {
        xfs_iext_realloc_indirect(ifp,
            nlists * sizeof(xfs_ext_irec_t));
    } else {
        kmem_free(ifp->if_u1.if_ext_irec);
    }
    ifp->if_real_bytes = nlists * XFS_IEXT_BUFSZ;
}

/*
 * This is called to clean up large amounts of unused memory allocated
 * by the indirection array.  Before compacting anything though, verify
 * that the indirection array is still needed and switch back to the
 * linear extent list (or even the inline buffer) if possible.  The
 * compaction policy is as follows:
 *
 *    Full Compaction: Extents fit into a single page (or inline buffer)
 * Partial Compaction: Extents occupy less than 50% of allocated space
 *      No Compaction: Extents occupy at least 50% of allocated space
 */
void
xfs_iext_irec_compact(
    xfs_ifork_t *ifp)       /* inode fork pointer */
{
    xfs_extnum_t    nextents;   /* number of extents in file */
    int     nlists;     /* number of irec's (ex lists) */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
    nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);

    if (nextents == 0) {
        xfs_iext_destroy(ifp);
    } else if (nextents <= XFS_INLINE_EXTS) {
        xfs_iext_indirect_to_direct(ifp);
        xfs_iext_direct_to_inline(ifp, nextents);
    } else if (nextents <= XFS_LINEAR_EXTS) {
        xfs_iext_indirect_to_direct(ifp);
    } else if (nextents < (nlists * XFS_LINEAR_EXTS) >> 1) {
        xfs_iext_irec_compact_pages(ifp);
    }
}

/*
 * Combine extents from neighboring extent pages.
 */
void
xfs_iext_irec_compact_pages(
    xfs_ifork_t *ifp)       /* inode fork pointer */
{
    xfs_ext_irec_t  *erp, *erp_next;/* pointers to irec entries */
    int     erp_idx = 0;    /* indirection array index */
    int     nlists;     /* number of irec's (ex lists) */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
    while (erp_idx < nlists - 1) {
        erp = &ifp->if_u1.if_ext_irec[erp_idx];
        erp_next = erp + 1;
        if (erp_next->er_extcount <=
            (XFS_LINEAR_EXTS - erp->er_extcount)) {
            memcpy(&erp->er_extbuf[erp->er_extcount],
                erp_next->er_extbuf, erp_next->er_extcount *
                sizeof(xfs_bmbt_rec_t));
            erp->er_extcount += erp_next->er_extcount;
            /*
             * Free page before removing extent record
             * so er_extoffs don't get modified in
             * xfs_iext_irec_remove.
             */
            kmem_free(erp_next->er_extbuf);
            erp_next->er_extbuf = NULL;
            xfs_iext_irec_remove(ifp, erp_idx + 1);
            nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
        } else {
            erp_idx++;
        }
    }
}

/*
 * This is called to update the er_extoff field in the indirection
 * array when extents have been added or removed from one of the
 * extent lists. erp_idx contains the irec index to begin updating
 * at and ext_diff contains the number of extents that were added
 * or removed.
 */
void
xfs_iext_irec_update_extoffs(
    xfs_ifork_t *ifp,       /* inode fork pointer */
    int     erp_idx,    /* irec index to update */
    int     ext_diff)   /* number of new extents */
{
    int     i;      /* loop counter */
    int     nlists;     /* number of irec's (ex lists */

    ASSERT(ifp->if_flags & XFS_IFEXTIREC);
    nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
    for (i = erp_idx; i < nlists; i++) {
        ifp->if_u1.if_ext_irec[i].er_extoff += ext_diff;
    }
}