jfs_imap.c

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/*
 *   Copyright (C) International Business Machines Corp., 2000-2004
 *
 *   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; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will 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 to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/*
 *  jfs_imap.c: inode allocation map manager
 *
 * Serialization:
 *   Each AG has a simple lock which is used to control the serialization of
 *  the AG level lists.  This lock should be taken first whenever an AG
 *  level list will be modified or accessed.
 *
 *   Each IAG is locked by obtaining the buffer for the IAG page.
 *
 *   There is also a inode lock for the inode map inode.  A read lock needs to
 *  be taken whenever an IAG is read from the map or the global level
 *  information is read.  A write lock needs to be taken whenever the global
 *  level information is modified or an atomic operation needs to be used.
 *
 *  If more than one IAG is read at one time, the read lock may not
 *  be given up until all of the IAG's are read.  Otherwise, a deadlock
 *  may occur when trying to obtain the read lock while another thread
 *  holding the read lock is waiting on the IAG already being held.
 *
 *   The control page of the inode map is read into memory by diMount().
 *  Thereafter it should only be modified in memory and then it will be
 *  written out when the filesystem is unmounted by diUnmount().
 */

#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/slab.h>

#include "jfs_incore.h"
#include "jfs_inode.h"
#include "jfs_filsys.h"
#include "jfs_dinode.h"
#include "jfs_dmap.h"
#include "jfs_imap.h"
#include "jfs_metapage.h"
#include "jfs_superblock.h"
#include "jfs_debug.h"

/*
 * imap locks
 */
/* iag free list lock */
#define IAGFREE_LOCK_INIT(imap)     mutex_init(&imap->im_freelock)
#define IAGFREE_LOCK(imap)      mutex_lock(&imap->im_freelock)
#define IAGFREE_UNLOCK(imap)        mutex_unlock(&imap->im_freelock)

/* per ag iag list locks */
#define AG_LOCK_INIT(imap,index)    mutex_init(&(imap->im_aglock[index]))
#define AG_LOCK(imap,agno)      mutex_lock(&imap->im_aglock[agno])
#define AG_UNLOCK(imap,agno)        mutex_unlock(&imap->im_aglock[agno])

/*
 * forward references
 */
static int diAllocAG(struct inomap *, int, bool, struct inode *);
static int diAllocAny(struct inomap *, int, bool, struct inode *);
static int diAllocBit(struct inomap *, struct iag *, int);
static int diAllocExt(struct inomap *, int, struct inode *);
static int diAllocIno(struct inomap *, int, struct inode *);
static int diFindFree(u32, int);
static int diNewExt(struct inomap *, struct iag *, int);
static int diNewIAG(struct inomap *, int *, int, struct metapage **);
static void duplicateIXtree(struct super_block *, s64, int, s64 *);

static int diIAGRead(struct inomap * imap, int, struct metapage **);
static int copy_from_dinode(struct dinode *, struct inode *);
static void copy_to_dinode(struct dinode *, struct inode *);

/*
 * NAME:    diMount()
 *
 * FUNCTION:    initialize the incore inode map control structures for
 *      a fileset or aggregate init time.
 *
 *      the inode map's control structure (dinomap) is
 *      brought in from disk and placed in virtual memory.
 *
 * PARAMETERS:
 *  ipimap  - pointer to inode map inode for the aggregate or fileset.
 *
 * RETURN VALUES:
 *  0   - success
 *  -ENOMEM - insufficient free virtual memory.
 *  -EIO    - i/o error.
 */
int diMount(struct inode *ipimap)
{
    struct inomap *imap;
    struct metapage *mp;
    int index;
    struct dinomap_disk *dinom_le;

    /*
     * allocate/initialize the in-memory inode map control structure
     */
    /* allocate the in-memory inode map control structure. */
    imap = kmalloc(sizeof(struct inomap), GFP_KERNEL);
    if (imap == NULL) {
        jfs_err("diMount: kmalloc returned NULL!");
        return -ENOMEM;
    }

    /* read the on-disk inode map control structure. */

    mp = read_metapage(ipimap,
               IMAPBLKNO << JFS_SBI(ipimap->i_sb)->l2nbperpage,
               PSIZE, 0);
    if (mp == NULL) {
        kfree(imap);
        return -EIO;
    }

    /* copy the on-disk version to the in-memory version. */
    dinom_le = (struct dinomap_disk *) mp->data;
    imap->im_freeiag = le32_to_cpu(dinom_le->in_freeiag);
    imap->im_nextiag = le32_to_cpu(dinom_le->in_nextiag);
    atomic_set(&imap->im_numinos, le32_to_cpu(dinom_le->in_numinos));
    atomic_set(&imap->im_numfree, le32_to_cpu(dinom_le->in_numfree));
    imap->im_nbperiext = le32_to_cpu(dinom_le->in_nbperiext);
    imap->im_l2nbperiext = le32_to_cpu(dinom_le->in_l2nbperiext);
    for (index = 0; index < MAXAG; index++) {
        imap->im_agctl[index].inofree =
            le32_to_cpu(dinom_le->in_agctl[index].inofree);
        imap->im_agctl[index].extfree =
            le32_to_cpu(dinom_le->in_agctl[index].extfree);
        imap->im_agctl[index].numinos =
            le32_to_cpu(dinom_le->in_agctl[index].numinos);
        imap->im_agctl[index].numfree =
            le32_to_cpu(dinom_le->in_agctl[index].numfree);
    }

    /* release the buffer. */
    release_metapage(mp);

    /*
     * allocate/initialize inode allocation map locks
     */
    /* allocate and init iag free list lock */
    IAGFREE_LOCK_INIT(imap);

    /* allocate and init ag list locks */
    for (index = 0; index < MAXAG; index++) {
        AG_LOCK_INIT(imap, index);
    }

    /* bind the inode map inode and inode map control structure
     * to each other.
     */
    imap->im_ipimap = ipimap;
    JFS_IP(ipimap)->i_imap = imap;

    return (0);
}


/*
 * NAME:    diUnmount()
 *
 * FUNCTION:    write to disk the incore inode map control structures for
 *      a fileset or aggregate at unmount time.
 *
 * PARAMETERS:
 *  ipimap  - pointer to inode map inode for the aggregate or fileset.
 *
 * RETURN VALUES:
 *  0   - success
 *  -ENOMEM - insufficient free virtual memory.
 *  -EIO    - i/o error.
 */
int diUnmount(struct inode *ipimap, int mounterror)
{
    struct inomap *imap = JFS_IP(ipimap)->i_imap;

    /*
     * update the on-disk inode map control structure
     */

    if (!(mounterror || isReadOnly(ipimap)))
        diSync(ipimap);

    /*
     * Invalidate the page cache buffers
     */
    truncate_inode_pages(ipimap->i_mapping, 0);

    /*
     * free in-memory control structure
     */
    kfree(imap);

    return (0);
}


/*
 *  diSync()
 */
int diSync(struct inode *ipimap)
{
    struct dinomap_disk *dinom_le;
    struct inomap *imp = JFS_IP(ipimap)->i_imap;
    struct metapage *mp;
    int index;

    /*
     * write imap global conrol page
     */
    /* read the on-disk inode map control structure */
    mp = get_metapage(ipimap,
              IMAPBLKNO << JFS_SBI(ipimap->i_sb)->l2nbperpage,
              PSIZE, 0);
    if (mp == NULL) {
        jfs_err("diSync: get_metapage failed!");
        return -EIO;
    }

    /* copy the in-memory version to the on-disk version */
    dinom_le = (struct dinomap_disk *) mp->data;
    dinom_le->in_freeiag = cpu_to_le32(imp->im_freeiag);
    dinom_le->in_nextiag = cpu_to_le32(imp->im_nextiag);
    dinom_le->in_numinos = cpu_to_le32(atomic_read(&imp->im_numinos));
    dinom_le->in_numfree = cpu_to_le32(atomic_read(&imp->im_numfree));
    dinom_le->in_nbperiext = cpu_to_le32(imp->im_nbperiext);
    dinom_le->in_l2nbperiext = cpu_to_le32(imp->im_l2nbperiext);
    for (index = 0; index < MAXAG; index++) {
        dinom_le->in_agctl[index].inofree =
            cpu_to_le32(imp->im_agctl[index].inofree);
        dinom_le->in_agctl[index].extfree =
            cpu_to_le32(imp->im_agctl[index].extfree);
        dinom_le->in_agctl[index].numinos =
            cpu_to_le32(imp->im_agctl[index].numinos);
        dinom_le->in_agctl[index].numfree =
            cpu_to_le32(imp->im_agctl[index].numfree);
    }

    /* write out the control structure */
    write_metapage(mp);

    /*
     * write out dirty pages of imap
     */
    filemap_write_and_wait(ipimap->i_mapping);

    diWriteSpecial(ipimap, 0);

    return (0);
}


/*
 * NAME:    diRead()
 *
 * FUNCTION:    initialize an incore inode from disk.
 *
 *      on entry, the specifed incore inode should itself
 *      specify the disk inode number corresponding to the
 *      incore inode (i.e. i_number should be initialized).
 *
 *      this routine handles incore inode initialization for
 *      both "special" and "regular" inodes.  special inodes
 *      are those required early in the mount process and
 *      require special handling since much of the file system
 *      is not yet initialized.  these "special" inodes are
 *      identified by a NULL inode map inode pointer and are
 *      actually initialized by a call to diReadSpecial().
 *
 *      for regular inodes, the iag describing the disk inode
 *      is read from disk to determine the inode extent address
 *      for the disk inode.  with the inode extent address in
 *      hand, the page of the extent that contains the disk
 *      inode is read and the disk inode is copied to the
 *      incore inode.
 *
 * PARAMETERS:
 *  ip  -  pointer to incore inode to be initialized from disk.
 *
 * RETURN VALUES:
 *  0   - success
 *  -EIO    - i/o error.
 *  -ENOMEM - insufficient memory
 *
 */
int diRead(struct inode *ip)
{
    struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
    int iagno, ino, extno, rc;
    struct inode *ipimap;
    struct dinode *dp;
    struct iag *iagp;
    struct metapage *mp;
    s64 blkno, agstart;
    struct inomap *imap;
    int block_offset;
    int inodes_left;
    unsigned long pageno;
    int rel_inode;

    jfs_info("diRead: ino = %ld", ip->i_ino);

    ipimap = sbi->ipimap;
    JFS_IP(ip)->ipimap = ipimap;

    /* determine the iag number for this inode (number) */
    iagno = INOTOIAG(ip->i_ino);

    /* read the iag */
    imap = JFS_IP(ipimap)->i_imap;
    IREAD_LOCK(ipimap, RDWRLOCK_IMAP);
    rc = diIAGRead(imap, iagno, &mp);
    IREAD_UNLOCK(ipimap);
    if (rc) {
        jfs_err("diRead: diIAGRead returned %d", rc);
        return (rc);
    }

    iagp = (struct iag *) mp->data;

    /* determine inode extent that holds the disk inode */
    ino = ip->i_ino & (INOSPERIAG - 1);
    extno = ino >> L2INOSPEREXT;

    if ((lengthPXD(&iagp->inoext[extno]) != imap->im_nbperiext) ||
        (addressPXD(&iagp->inoext[extno]) == 0)) {
        release_metapage(mp);
        return -ESTALE;
    }

    /* get disk block number of the page within the inode extent
     * that holds the disk inode.
     */
    blkno = INOPBLK(&iagp->inoext[extno], ino, sbi->l2nbperpage);

    /* get the ag for the iag */
    agstart = le64_to_cpu(iagp->agstart);

    release_metapage(mp);

    rel_inode = (ino & (INOSPERPAGE - 1));
    pageno = blkno >> sbi->l2nbperpage;

    if ((block_offset = ((u32) blkno & (sbi->nbperpage - 1)))) {
        /*
         * OS/2 didn't always align inode extents on page boundaries
         */
        inodes_left =
             (sbi->nbperpage - block_offset) << sbi->l2niperblk;

        if (rel_inode < inodes_left)
            rel_inode += block_offset << sbi->l2niperblk;
        else {
            pageno += 1;
            rel_inode -= inodes_left;
        }
    }

    /* read the page of disk inode */
    mp = read_metapage(ipimap, pageno << sbi->l2nbperpage, PSIZE, 1);
    if (!mp) {
        jfs_err("diRead: read_metapage failed");
        return -EIO;
    }

    /* locate the disk inode requested */
    dp = (struct dinode *) mp->data;
    dp += rel_inode;

    if (ip->i_ino != le32_to_cpu(dp->di_number)) {
        jfs_error(ip->i_sb, "diRead: i_ino != di_number");
        rc = -EIO;
    } else if (le32_to_cpu(dp->di_nlink) == 0)
        rc = -ESTALE;
    else
        /* copy the disk inode to the in-memory inode */
        rc = copy_from_dinode(dp, ip);

    release_metapage(mp);

    /* set the ag for the inode */
    JFS_IP(ip)->agstart = agstart;
    JFS_IP(ip)->active_ag = -1;

    return (rc);
}


/*
 * NAME:    diReadSpecial()
 *
 * FUNCTION:    initialize a 'special' inode from disk.
 *
 *      this routines handles aggregate level inodes.  The
 *      inode cache cannot differentiate between the
 *      aggregate inodes and the filesystem inodes, so we
 *      handle these here.  We don't actually use the aggregate
 *      inode map, since these inodes are at a fixed location
 *      and in some cases the aggregate inode map isn't initialized
 *      yet.
 *
 * PARAMETERS:
 *  sb - filesystem superblock
 *  inum - aggregate inode number
 *  secondary - 1 if secondary aggregate inode table
 *
 * RETURN VALUES:
 *  new inode   - success
 *  NULL        - i/o error.
 */
struct inode *diReadSpecial(struct super_block *sb, ino_t inum, int secondary)
{
    struct jfs_sb_info *sbi = JFS_SBI(sb);
    uint address;
    struct dinode *dp;
    struct inode *ip;
    struct metapage *mp;

    ip = new_inode(sb);
    if (ip == NULL) {
        jfs_err("diReadSpecial: new_inode returned NULL!");
        return ip;
    }

    if (secondary) {
        address = addressPXD(&sbi->ait2) >> sbi->l2nbperpage;
        JFS_IP(ip)->ipimap = sbi->ipaimap2;
    } else {
        address = AITBL_OFF >> L2PSIZE;
        JFS_IP(ip)->ipimap = sbi->ipaimap;
    }

    ASSERT(inum < INOSPEREXT);

    ip->i_ino = inum;

    address += inum >> 3;   /* 8 inodes per 4K page */

    /* read the page of fixed disk inode (AIT) in raw mode */
    mp = read_metapage(ip, address << sbi->l2nbperpage, PSIZE, 1);
    if (mp == NULL) {
        set_nlink(ip, 1);   /* Don't want iput() deleting it */
        iput(ip);
        return (NULL);
    }

    /* get the pointer to the disk inode of interest */
    dp = (struct dinode *) (mp->data);
    dp += inum % 8;     /* 8 inodes per 4K page */

    /* copy on-disk inode to in-memory inode */
    if ((copy_from_dinode(dp, ip)) != 0) {
        /* handle bad return by returning NULL for ip */
        set_nlink(ip, 1);   /* Don't want iput() deleting it */
        iput(ip);
        /* release the page */
        release_metapage(mp);
        return (NULL);

    }

    ip->i_mapping->a_ops = &jfs_metapage_aops;
    mapping_set_gfp_mask(ip->i_mapping, GFP_NOFS);

    /* Allocations to metadata inodes should not affect quotas */
    ip->i_flags |= S_NOQUOTA;

    if ((inum == FILESYSTEM_I) && (JFS_IP(ip)->ipimap == sbi->ipaimap)) {
        sbi->gengen = le32_to_cpu(dp->di_gengen);
        sbi->inostamp = le32_to_cpu(dp->di_inostamp);
    }

    /* release the page */
    release_metapage(mp);

    /*
     * __mark_inode_dirty expects inodes to be hashed.  Since we don't
     * want special inodes in the fileset inode space, we make them
     * appear hashed, but do not put on any lists.  hlist_del()
     * will work fine and require no locking.
     */
    hlist_add_fake(&ip->i_hash);

    return (ip);
}

/*
 * NAME:    diWriteSpecial()
 *
 * FUNCTION:    Write the special inode to disk
 *
 * PARAMETERS:
 *  ip - special inode
 *  secondary - 1 if secondary aggregate inode table
 *
 * RETURN VALUES: none
 */

void diWriteSpecial(struct inode *ip, int secondary)
{
    struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
    uint address;
    struct dinode *dp;
    ino_t inum = ip->i_ino;
    struct metapage *mp;

    if (secondary)
        address = addressPXD(&sbi->ait2) >> sbi->l2nbperpage;
    else
        address = AITBL_OFF >> L2PSIZE;

    ASSERT(inum < INOSPEREXT);

    address += inum >> 3;   /* 8 inodes per 4K page */

    /* read the page of fixed disk inode (AIT) in raw mode */
    mp = read_metapage(ip, address << sbi->l2nbperpage, PSIZE, 1);
    if (mp == NULL) {
        jfs_err("diWriteSpecial: failed to read aggregate inode "
            "extent!");
        return;
    }

    /* get the pointer to the disk inode of interest */
    dp = (struct dinode *) (mp->data);
    dp += inum % 8;     /* 8 inodes per 4K page */

    /* copy on-disk inode to in-memory inode */
    copy_to_dinode(dp, ip);
    memcpy(&dp->di_xtroot, &JFS_IP(ip)->i_xtroot, 288);

    if (inum == FILESYSTEM_I)
        dp->di_gengen = cpu_to_le32(sbi->gengen);

    /* write the page */
    write_metapage(mp);
}

/*
 * NAME:    diFreeSpecial()
 *
 * FUNCTION:    Free allocated space for special inode
 */
void diFreeSpecial(struct inode *ip)
{
    if (ip == NULL) {
        jfs_err("diFreeSpecial called with NULL ip!");
        return;
    }
    filemap_write_and_wait(ip->i_mapping);
    truncate_inode_pages(ip->i_mapping, 0);
    iput(ip);
}



/*
 * NAME:    diWrite()
 *
 * FUNCTION:    write the on-disk inode portion of the in-memory inode
 *      to its corresponding on-disk inode.
 *
 *      on entry, the specifed incore inode should itself
 *      specify the disk inode number corresponding to the
 *      incore inode (i.e. i_number should be initialized).
 *
 *      the inode contains the inode extent address for the disk
 *      inode.  with the inode extent address in hand, the
 *      page of the extent that contains the disk inode is
 *      read and the disk inode portion of the incore inode
 *      is copied to the disk inode.
 *
 * PARAMETERS:
 *  tid -  transacation id
 *  ip  -  pointer to incore inode to be written to the inode extent.
 *
 * RETURN VALUES:
 *  0   - success
 *  -EIO    - i/o error.
 */
int diWrite(tid_t tid, struct inode *ip)
{
    struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
    struct jfs_inode_info *jfs_ip = JFS_IP(ip);
    int rc = 0;
    s32 ino;
    struct dinode *dp;
    s64 blkno;
    int block_offset;
    int inodes_left;
    struct metapage *mp;
    unsigned long pageno;
    int rel_inode;
    int dioffset;
    struct inode *ipimap;
    uint type;
    lid_t lid;
    struct tlock *ditlck, *tlck;
    struct linelock *dilinelock, *ilinelock;
    struct lv *lv;
    int n;

    ipimap = jfs_ip->ipimap;

    ino = ip->i_ino & (INOSPERIAG - 1);

    if (!addressPXD(&(jfs_ip->ixpxd)) ||
        (lengthPXD(&(jfs_ip->ixpxd)) !=
         JFS_IP(ipimap)->i_imap->im_nbperiext)) {
        jfs_error(ip->i_sb, "diWrite: ixpxd invalid");
        return -EIO;
    }

    /*
     * read the page of disk inode containing the specified inode:
     */
    /* compute the block address of the page */
    blkno = INOPBLK(&(jfs_ip->ixpxd), ino, sbi->l2nbperpage);

    rel_inode = (ino & (INOSPERPAGE - 1));
    pageno = blkno >> sbi->l2nbperpage;

    if ((block_offset = ((u32) blkno & (sbi->nbperpage - 1)))) {
        /*
         * OS/2 didn't always align inode extents on page boundaries
         */
        inodes_left =
            (sbi->nbperpage - block_offset) << sbi->l2niperblk;

        if (rel_inode < inodes_left)
            rel_inode += block_offset << sbi->l2niperblk;
        else {
            pageno += 1;
            rel_inode -= inodes_left;
        }
    }
    /* read the page of disk inode */
      retry:
    mp = read_metapage(ipimap, pageno << sbi->l2nbperpage, PSIZE, 1);
    if (!mp)
        return -EIO;

    /* get the pointer to the disk inode */
    dp = (struct dinode *) mp->data;
    dp += rel_inode;

    dioffset = (ino & (INOSPERPAGE - 1)) << L2DISIZE;

    /*
     * acquire transaction lock on the on-disk inode;
     * N.B. tlock is acquired on ipimap not ip;
     */
    if ((ditlck =
         txLock(tid, ipimap, mp, tlckINODE | tlckENTRY)) == NULL)
        goto retry;
    dilinelock = (struct linelock *) & ditlck->lock;

    /*
     * copy btree root from in-memory inode to on-disk inode
     *
     * (tlock is taken from inline B+-tree root in in-memory
     * inode when the B+-tree root is updated, which is pointed
     * by jfs_ip->blid as well as being on tx tlock list)
     *
     * further processing of btree root is based on the copy
     * in in-memory inode, where txLog() will log from, and,
     * for xtree root, txUpdateMap() will update map and reset
     * XAD_NEW bit;
     */

    if (S_ISDIR(ip->i_mode) && (lid = jfs_ip->xtlid)) {
        /*
         * This is the special xtree inside the directory for storing
         * the directory table
         */
        xtpage_t *p, *xp;
        xad_t *xad;

        jfs_ip->xtlid = 0;
        tlck = lid_to_tlock(lid);
        assert(tlck->type & tlckXTREE);
        tlck->type |= tlckBTROOT;
        tlck->mp = mp;
        ilinelock = (struct linelock *) & tlck->lock;

        /*
         * copy xtree root from inode to dinode:
         */
        p = &jfs_ip->i_xtroot;
        xp = (xtpage_t *) &dp->di_dirtable;
        lv = ilinelock->lv;
        for (n = 0; n < ilinelock->index; n++, lv++) {
            memcpy(&xp->xad[lv->offset], &p->xad[lv->offset],
                   lv->length << L2XTSLOTSIZE);
        }

        /* reset on-disk (metadata page) xtree XAD_NEW bit */
        xad = &xp->xad[XTENTRYSTART];
        for (n = XTENTRYSTART;
             n < le16_to_cpu(xp->header.nextindex); n++, xad++)
            if (xad->flag & (XAD_NEW | XAD_EXTENDED))
                xad->flag &= ~(XAD_NEW | XAD_EXTENDED);
    }

    if ((lid = jfs_ip->blid) == 0)
        goto inlineData;
    jfs_ip->blid = 0;

    tlck = lid_to_tlock(lid);
    type = tlck->type;
    tlck->type |= tlckBTROOT;
    tlck->mp = mp;
    ilinelock = (struct linelock *) & tlck->lock;

    /*
     *  regular file: 16 byte (XAD slot) granularity
     */
    if (type & tlckXTREE) {
        xtpage_t *p, *xp;
        xad_t *xad;

        /*
         * copy xtree root from inode to dinode:
         */
        p = &jfs_ip->i_xtroot;
        xp = &dp->di_xtroot;
        lv = ilinelock->lv;
        for (n = 0; n < ilinelock->index; n++, lv++) {
            memcpy(&xp->xad[lv->offset], &p->xad[lv->offset],
                   lv->length << L2XTSLOTSIZE);
        }

        /* reset on-disk (metadata page) xtree XAD_NEW bit */
        xad = &xp->xad[XTENTRYSTART];
        for (n = XTENTRYSTART;
             n < le16_to_cpu(xp->header.nextindex); n++, xad++)
            if (xad->flag & (XAD_NEW | XAD_EXTENDED))
                xad->flag &= ~(XAD_NEW | XAD_EXTENDED);
    }
    /*
     *  directory: 32 byte (directory entry slot) granularity
     */
    else if (type & tlckDTREE) {
        dtpage_t *p, *xp;

        /*
         * copy dtree root from inode to dinode:
         */
        p = (dtpage_t *) &jfs_ip->i_dtroot;
        xp = (dtpage_t *) & dp->di_dtroot;
        lv = ilinelock->lv;
        for (n = 0; n < ilinelock->index; n++, lv++) {
            memcpy(&xp->slot[lv->offset], &p->slot[lv->offset],
                   lv->length << L2DTSLOTSIZE);
        }
    } else {
        jfs_err("diWrite: UFO tlock");
    }

      inlineData:
    /*
     * copy inline symlink from in-memory inode to on-disk inode
     */
    if (S_ISLNK(ip->i_mode) && ip->i_size < IDATASIZE) {
        lv = & dilinelock->lv[dilinelock->index];
        lv->offset = (dioffset + 2 * 128) >> L2INODESLOTSIZE;
        lv->length = 2;
        memcpy(&dp->di_fastsymlink, jfs_ip->i_inline, IDATASIZE);
        dilinelock->index++;
    }
    /*
     * copy inline data from in-memory inode to on-disk inode:
     * 128 byte slot granularity
     */
    if (test_cflag(COMMIT_Inlineea, ip)) {
        lv = & dilinelock->lv[dilinelock->index];
        lv->offset = (dioffset + 3 * 128) >> L2INODESLOTSIZE;
        lv->length = 1;
        memcpy(&dp->di_inlineea, jfs_ip->i_inline_ea, INODESLOTSIZE);
        dilinelock->index++;

        clear_cflag(COMMIT_Inlineea, ip);
    }

    /*
     *  lock/copy inode base: 128 byte slot granularity
     */
    lv = & dilinelock->lv[dilinelock->index];
    lv->offset = dioffset >> L2INODESLOTSIZE;
    copy_to_dinode(dp, ip);
    if (test_and_clear_cflag(COMMIT_Dirtable, ip)) {
        lv->length = 2;
        memcpy(&dp->di_dirtable, &jfs_ip->i_dirtable, 96);
    } else
        lv->length = 1;
    dilinelock->index++;

    /* release the buffer holding the updated on-disk inode.
     * the buffer will be later written by commit processing.
     */
    write_metapage(mp);

    return (rc);
}


/*
 * NAME:    diFree(ip)
 *
 * FUNCTION:    free a specified inode from the inode working map
 *      for a fileset or aggregate.
 *
 *      if the inode to be freed represents the first (only)
 *      free inode within the iag, the iag will be placed on
 *      the ag free inode list.
 *
 *      freeing the inode will cause the inode extent to be
 *      freed if the inode is the only allocated inode within
 *      the extent.  in this case all the disk resource backing
 *      up the inode extent will be freed. in addition, the iag
 *      will be placed on the ag extent free list if the extent
 *      is the first free extent in the iag.  if freeing the
 *      extent also means that no free inodes will exist for
 *      the iag, the iag will also be removed from the ag free
 *      inode list.
 *
 *      the iag describing the inode will be freed if the extent
 *      is to be freed and it is the only backed extent within
 *      the iag.  in this case, the iag will be removed from the
 *      ag free extent list and ag free inode list and placed on
 *      the inode map's free iag list.
 *
 *      a careful update approach is used to provide consistency
 *      in the face of updates to multiple buffers.  under this
 *      approach, all required buffers are obtained before making
 *      any updates and are held until all updates are complete.
 *
 * PARAMETERS:
 *  ip  - inode to be freed.
 *
 * RETURN VALUES:
 *  0   - success
 *  -EIO    - i/o error.
 */
int diFree(struct inode *ip)
{
    int rc;
    ino_t inum = ip->i_ino;
    struct iag *iagp, *aiagp, *biagp, *ciagp, *diagp;
    struct metapage *mp, *amp, *bmp, *cmp, *dmp;
    int iagno, ino, extno, bitno, sword, agno;
    int back, fwd;
    u32 bitmap, mask;
    struct inode *ipimap = JFS_SBI(ip->i_sb)->ipimap;
    struct inomap *imap = JFS_IP(ipimap)->i_imap;
    pxd_t freepxd;
    tid_t tid;
    struct inode *iplist[3];
    struct tlock *tlck;
    struct pxd_lock *pxdlock;

    /*
     * This is just to suppress compiler warnings.  The same logic that
     * references these variables is used to initialize them.
     */
    aiagp = biagp = ciagp = diagp = NULL;

    /* get the iag number containing the inode.
     */
    iagno = INOTOIAG(inum);

    /* make sure that the iag is contained within
     * the map.
     */
    if (iagno >= imap->im_nextiag) {
        print_hex_dump(KERN_ERR, "imap: ", DUMP_PREFIX_ADDRESS, 16, 4,
                   imap, 32, 0);
        jfs_error(ip->i_sb,
              "diFree: inum = %d, iagno = %d, nextiag = %d",
              (uint) inum, iagno, imap->im_nextiag);
        return -EIO;
    }

    /* get the allocation group for this ino.
     */
    agno = BLKTOAG(JFS_IP(ip)->agstart, JFS_SBI(ip->i_sb));

    /* Lock the AG specific inode map information
     */
    AG_LOCK(imap, agno);

    /* Obtain read lock in imap inode.  Don't release it until we have
     * read all of the IAG's that we are going to.
     */
    IREAD_LOCK(ipimap, RDWRLOCK_IMAP);

    /* read the iag.
     */
    if ((rc = diIAGRead(imap, iagno, &mp))) {
        IREAD_UNLOCK(ipimap);
        AG_UNLOCK(imap, agno);
        return (rc);
    }
    iagp = (struct iag *) mp->data;

    /* get the inode number and extent number of the inode within
     * the iag and the inode number within the extent.
     */
    ino = inum & (INOSPERIAG - 1);
    extno = ino >> L2INOSPEREXT;
    bitno = ino & (INOSPEREXT - 1);
    mask = HIGHORDER >> bitno;

    if (!(le32_to_cpu(iagp->wmap[extno]) & mask)) {
        jfs_error(ip->i_sb,
              "diFree: wmap shows inode already free");
    }

    if (!addressPXD(&iagp->inoext[extno])) {
        release_metapage(mp);
        IREAD_UNLOCK(ipimap);
        AG_UNLOCK(imap, agno);
        jfs_error(ip->i_sb, "diFree: invalid inoext");
        return -EIO;
    }

    /* compute the bitmap for the extent reflecting the freed inode.
     */
    bitmap = le32_to_cpu(iagp->wmap[extno]) & ~mask;

    if (imap->im_agctl[agno].numfree > imap->im_agctl[agno].numinos) {
        release_metapage(mp);
        IREAD_UNLOCK(ipimap);
        AG_UNLOCK(imap, agno);
        jfs_error(ip->i_sb, "diFree: numfree > numinos");
        return -EIO;
    }
    /*
     *  inode extent still has some inodes or below low water mark:
     *  keep the inode extent;
     */
    if (bitmap ||
        imap->im_agctl[agno].numfree < 96 ||
        (imap->im_agctl[agno].numfree < 288 &&
         (((imap->im_agctl[agno].numfree * 100) /
           imap->im_agctl[agno].numinos) <= 25))) {
        /* if the iag currently has no free inodes (i.e.,
         * the inode being freed is the first free inode of iag),
         * insert the iag at head of the inode free list for the ag.
         */
        if (iagp->nfreeinos == 0) {
            /* check if there are any iags on the ag inode
             * free list.  if so, read the first one so that
             * we can link the current iag onto the list at
             * the head.
             */
            if ((fwd = imap->im_agctl[agno].inofree) >= 0) {
                /* read the iag that currently is the head
                 * of the list.
                 */
                if ((rc = diIAGRead(imap, fwd, &amp))) {
                    IREAD_UNLOCK(ipimap);
                    AG_UNLOCK(imap, agno);
                    release_metapage(mp);
                    return (rc);
                }
                aiagp = (struct iag *) amp->data;

                /* make current head point back to the iag.
                 */
                aiagp->inofreeback = cpu_to_le32(iagno);

                write_metapage(amp);
            }

            /* iag points forward to current head and iag
             * becomes the new head of the list.
             */
            iagp->inofreefwd =
                cpu_to_le32(imap->im_agctl[agno].inofree);
            iagp->inofreeback = cpu_to_le32(-1);
            imap->im_agctl[agno].inofree = iagno;
        }
        IREAD_UNLOCK(ipimap);

        /* update the free inode summary map for the extent if
         * freeing the inode means the extent will now have free
         * inodes (i.e., the inode being freed is the first free
         * inode of extent),
         */
        if (iagp->wmap[extno] == cpu_to_le32(ONES)) {
            sword = extno >> L2EXTSPERSUM;
            bitno = extno & (EXTSPERSUM - 1);
            iagp->inosmap[sword] &=
                cpu_to_le32(~(HIGHORDER >> bitno));
        }

        /* update the bitmap.
         */
        iagp->wmap[extno] = cpu_to_le32(bitmap);

        /* update the free inode counts at the iag, ag and
         * map level.
         */
        le32_add_cpu(&iagp->nfreeinos, 1);
        imap->im_agctl[agno].numfree += 1;
        atomic_inc(&imap->im_numfree);

        /* release the AG inode map lock
         */
        AG_UNLOCK(imap, agno);

        /* write the iag */
        write_metapage(mp);

        return (0);
    }


    /*
     *  inode extent has become free and above low water mark:
     *  free the inode extent;
     */

    /*
     *  prepare to update iag list(s) (careful update step 1)
     */
    amp = bmp = cmp = dmp = NULL;
    fwd = back = -1;

    /* check if the iag currently has no free extents.  if so,
     * it will be placed on the head of the ag extent free list.
     */
    if (iagp->nfreeexts == 0) {
        /* check if the ag extent free list has any iags.
         * if so, read the iag at the head of the list now.
         * this (head) iag will be updated later to reflect
         * the addition of the current iag at the head of
         * the list.
         */
        if ((fwd = imap->im_agctl[agno].extfree) >= 0) {
            if ((rc = diIAGRead(imap, fwd, &amp)))
                goto error_out;
            aiagp = (struct iag *) amp->data;
        }
    } else {
        /* iag has free extents. check if the addition of a free
         * extent will cause all extents to be free within this
         * iag.  if so, the iag will be removed from the ag extent
         * free list and placed on the inode map's free iag list.
         */
        if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG - 1)) {
            /* in preparation for removing the iag from the
             * ag extent free list, read the iags preceding
             * and following the iag on the ag extent free
             * list.
             */
            if ((fwd = le32_to_cpu(iagp->extfreefwd)) >= 0) {
                if ((rc = diIAGRead(imap, fwd, &amp)))
                    goto error_out;
                aiagp = (struct iag *) amp->data;
            }

            if ((back = le32_to_cpu(iagp->extfreeback)) >= 0) {
                if ((rc = diIAGRead(imap, back, &bmp)))
                    goto error_out;
                biagp = (struct iag *) bmp->data;
            }
        }
    }

    /* remove the iag from the ag inode free list if freeing
     * this extent cause the iag to have no free inodes.
     */
    if (iagp->nfreeinos == cpu_to_le32(INOSPEREXT - 1)) {
        int inofreeback = le32_to_cpu(iagp->inofreeback);
        int inofreefwd = le32_to_cpu(iagp->inofreefwd);

        /* in preparation for removing the iag from the
         * ag inode free list, read the iags preceding
         * and following the iag on the ag inode free
         * list.  before reading these iags, we must make
         * sure that we already don't have them in hand
         * from up above, since re-reading an iag (buffer)
         * we are currently holding would cause a deadlock.
         */
        if (inofreefwd >= 0) {

            if (inofreefwd == fwd)
                ciagp = (struct iag *) amp->data;
            else if (inofreefwd == back)
                ciagp = (struct iag *) bmp->data;
            else {
                if ((rc =
                     diIAGRead(imap, inofreefwd, &cmp)))
                    goto error_out;
                ciagp = (struct iag *) cmp->data;
            }
            assert(ciagp != NULL);
        }

        if (inofreeback >= 0) {
            if (inofreeback == fwd)
                diagp = (struct iag *) amp->data;
            else if (inofreeback == back)
                diagp = (struct iag *) bmp->data;
            else {
                if ((rc =
                     diIAGRead(imap, inofreeback, &dmp)))
                    goto error_out;
                diagp = (struct iag *) dmp->data;
            }
            assert(diagp != NULL);
        }
    }

    IREAD_UNLOCK(ipimap);

    /*
     * invalidate any page of the inode extent freed from buffer cache;
     */
    freepxd = iagp->inoext[extno];
    invalidate_pxd_metapages(ip, freepxd);

    /*
     *  update iag list(s) (careful update step 2)
     */
    /* add the iag to the ag extent free list if this is the
     * first free extent for the iag.
     */
    if (iagp->nfreeexts == 0) {
        if (fwd >= 0)
            aiagp->extfreeback = cpu_to_le32(iagno);

        iagp->extfreefwd =
            cpu_to_le32(imap->im_agctl[agno].extfree);
        iagp->extfreeback = cpu_to_le32(-1);
        imap->im_agctl[agno].extfree = iagno;
    } else {
        /* remove the iag from the ag extent list if all extents
         * are now free and place it on the inode map iag free list.
         */
        if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG - 1)) {
            if (fwd >= 0)
                aiagp->extfreeback = iagp->extfreeback;

            if (back >= 0)
                biagp->extfreefwd = iagp->extfreefwd;
            else
                imap->im_agctl[agno].extfree =
                    le32_to_cpu(iagp->extfreefwd);

            iagp->extfreefwd = iagp->extfreeback = cpu_to_le32(-1);

            IAGFREE_LOCK(imap);
            iagp->iagfree = cpu_to_le32(imap->im_freeiag);
            imap->im_freeiag = iagno;
            IAGFREE_UNLOCK(imap);
        }
    }

    /* remove the iag from the ag inode free list if freeing
     * this extent causes the iag to have no free inodes.
     */
    if (iagp->nfreeinos == cpu_to_le32(INOSPEREXT - 1)) {
        if ((int) le32_to_cpu(iagp->inofreefwd) >= 0)
            ciagp->inofreeback = iagp->inofreeback;

        if ((int) le32_to_cpu(iagp->inofreeback) >= 0)
            diagp->inofreefwd = iagp->inofreefwd;
        else
            imap->im_agctl[agno].inofree =
                le32_to_cpu(iagp->inofreefwd);

        iagp->inofreefwd = iagp->inofreeback = cpu_to_le32(-1);
    }

    /* update the inode extent address and working map
     * to reflect the free extent.
     * the permanent map should have been updated already
     * for the inode being freed.
     */
    if (iagp->pmap[extno] != 0) {
        jfs_error(ip->i_sb, "diFree: the pmap does not show inode free");
    }
    iagp->wmap[extno] = 0;
    PXDlength(&iagp->inoext[extno], 0);
    PXDaddress(&iagp->inoext[extno], 0);

    /* update the free extent and free inode summary maps
     * to reflect the freed extent.
     * the inode summary map is marked to indicate no inodes
     * available for the freed extent.
     */
    sword = extno >> L2EXTSPERSUM;
    bitno = extno & (EXTSPERSUM - 1);
    mask = HIGHORDER >> bitno;
    iagp->inosmap[sword] |= cpu_to_le32(mask);
    iagp->extsmap[sword] &= cpu_to_le32(~mask);

    /* update the number of free inodes and number of free extents
     * for the iag.
     */
    le32_add_cpu(&iagp->nfreeinos, -(INOSPEREXT - 1));
    le32_add_cpu(&iagp->nfreeexts, 1);

    /* update the number of free inodes and backed inodes
     * at the ag and inode map level.
     */
    imap->im_agctl[agno].numfree -= (INOSPEREXT - 1);
    imap->im_agctl[agno].numinos -= INOSPEREXT;
    atomic_sub(INOSPEREXT - 1, &imap->im_numfree);
    atomic_sub(INOSPEREXT, &imap->im_numinos);

    if (amp)
        write_metapage(amp);
    if (bmp)
        write_metapage(bmp);
    if (cmp)
        write_metapage(cmp);
    if (dmp)
        write_metapage(dmp);

    /*
     * start transaction to update block allocation map
     * for the inode extent freed;
     *
     * N.B. AG_LOCK is released and iag will be released below, and
     * other thread may allocate inode from/reusing the ixad freed
     * BUT with new/different backing inode extent from the extent
     * to be freed by the transaction;
     */
    tid = txBegin(ipimap->i_sb, COMMIT_FORCE);
    mutex_lock(&JFS_IP(ipimap)->commit_mutex);

    /* acquire tlock of the iag page of the freed ixad
     * to force the page NOHOMEOK (even though no data is
     * logged from the iag page) until NOREDOPAGE|FREEXTENT log
     * for the free of the extent is committed;
     * write FREEXTENT|NOREDOPAGE log record
     * N.B. linelock is overlaid as freed extent descriptor;
     */
    tlck = txLock(tid, ipimap, mp, tlckINODE | tlckFREE);
    pxdlock = (struct pxd_lock *) & tlck->lock;
    pxdlock->flag = mlckFREEPXD;
    pxdlock->pxd = freepxd;
    pxdlock->index = 1;

    write_metapage(mp);

    iplist[0] = ipimap;

    /*
     * logredo needs the IAG number and IAG extent index in order
     * to ensure that the IMap is consistent.  The least disruptive
     * way to pass these values through  to the transaction manager
     * is in the iplist array.
     *
     * It's not pretty, but it works.
     */
    iplist[1] = (struct inode *) (size_t)iagno;
    iplist[2] = (struct inode *) (size_t)extno;

    rc = txCommit(tid, 1, &iplist[0], COMMIT_FORCE);

    txEnd(tid);
    mutex_unlock(&JFS_IP(ipimap)->commit_mutex);

    /* unlock the AG inode map information */
    AG_UNLOCK(imap, agno);

    return (0);

      error_out:
    IREAD_UNLOCK(ipimap);

    if (amp)
        release_metapage(amp);
    if (bmp)
        release_metapage(bmp);
    if (cmp)
        release_metapage(cmp);
    if (dmp)
        release_metapage(dmp);

    AG_UNLOCK(imap, agno);

    release_metapage(mp);

    return (rc);
}

/*
 * There are several places in the diAlloc* routines where we initialize
 * the inode.
 */
static inline void
diInitInode(struct inode *ip, int iagno, int ino, int extno, struct iag * iagp)
{
    struct jfs_inode_info *jfs_ip = JFS_IP(ip);

    ip->i_ino = (iagno << L2INOSPERIAG) + ino;
    jfs_ip->ixpxd = iagp->inoext[extno];
    jfs_ip->agstart = le64_to_cpu(iagp->agstart);
    jfs_ip->active_ag = -1;
}


/*
 * NAME:    diAlloc(pip,dir,ip)
 *
 * FUNCTION:    allocate a disk inode from the inode working map
 *      for a fileset or aggregate.
 *
 * PARAMETERS:
 *  pip - pointer to incore inode for the parent inode.
 *  dir - 'true' if the new disk inode is for a directory.
 *  ip  - pointer to a new inode
 *
 * RETURN VALUES:
 *  0   - success.
 *  -ENOSPC - insufficient disk resources.
 *  -EIO    - i/o error.
 */
int diAlloc(struct inode *pip, bool dir, struct inode *ip)
{
    int rc, ino, iagno, addext, extno, bitno, sword;
    int nwords, rem, i, agno;
    u32 mask, inosmap, extsmap;
    struct inode *ipimap;
    struct metapage *mp;
    ino_t inum;
    struct iag *iagp;
    struct inomap *imap;

    /* get the pointers to the inode map inode and the
     * corresponding imap control structure.
     */
    ipimap = JFS_SBI(pip->i_sb)->ipimap;
    imap = JFS_IP(ipimap)->i_imap;
    JFS_IP(ip)->ipimap = ipimap;
    JFS_IP(ip)->fileset = FILESYSTEM_I;

    /* for a directory, the allocation policy is to start
     * at the ag level using the preferred ag.
     */
    if (dir) {
        agno = dbNextAG(JFS_SBI(pip->i_sb)->ipbmap);
        AG_LOCK(imap, agno);
        goto tryag;
    }

    /* for files, the policy starts off by trying to allocate from
     * the same iag containing the parent disk inode:
     * try to allocate the new disk inode close to the parent disk
     * inode, using parent disk inode number + 1 as the allocation
     * hint.  (we use a left-to-right policy to attempt to avoid
     * moving backward on the disk.)  compute the hint within the
     * file system and the iag.
     */

    /* get the ag number of this iag */
    agno = BLKTOAG(JFS_IP(pip)->agstart, JFS_SBI(pip->i_sb));

    if (atomic_read(&JFS_SBI(pip->i_sb)->bmap->db_active[agno])) {
        /*
         * There is an open file actively growing.  We want to
         * allocate new inodes from a different ag to avoid
         * fragmentation problems.
         */
        agno = dbNextAG(JFS_SBI(pip->i_sb)->ipbmap);
        AG_LOCK(imap, agno);
        goto tryag;
    }

    inum = pip->i_ino + 1;
    ino = inum & (INOSPERIAG - 1);

    /* back off the hint if it is outside of the iag */
    if (ino == 0)
        inum = pip->i_ino;

    /* lock the AG inode map information */
    AG_LOCK(imap, agno);

    /* Get read lock on imap inode */
    IREAD_LOCK(ipimap, RDWRLOCK_IMAP);

    /* get the iag number and read the iag */
    iagno = INOTOIAG(inum);
    if ((rc = diIAGRead(imap, iagno, &mp))) {
        IREAD_UNLOCK(ipimap);
        AG_UNLOCK(imap, agno);
        return (rc);
    }
    iagp = (struct iag *) mp->data;

    /* determine if new inode extent is allowed to be added to the iag.
     * new inode extent can be added to the iag if the ag
     * has less than 32 free disk inodes and the iag has free extents.
     */
    addext = (imap->im_agctl[agno].numfree < 32 && iagp->nfreeexts);

    /*
     *  try to allocate from the IAG
     */
    /* check if the inode may be allocated from the iag
     * (i.e. the inode has free inodes or new extent can be added).
     */
    if (iagp->nfreeinos || addext) {
        /* determine the extent number of the hint.
         */
        extno = ino >> L2INOSPEREXT;

        /* check if the extent containing the hint has backed
         * inodes.  if so, try to allocate within this extent.
         */
        if (addressPXD(&iagp->inoext[extno])) {
            bitno = ino & (INOSPEREXT - 1);
            if ((bitno =
                 diFindFree(le32_to_cpu(iagp->wmap[extno]),
                    bitno))
                < INOSPEREXT) {
                ino = (extno << L2INOSPEREXT) + bitno;

                /* a free inode (bit) was found within this
                 * extent, so allocate it.
                 */
                rc = diAllocBit(imap, iagp, ino);
                IREAD_UNLOCK(ipimap);
                if (rc) {
                    assert(rc == -EIO);
                } else {
                    /* set the results of the allocation
                     * and write the iag.
                     */
                    diInitInode(ip, iagno, ino, extno,
                            iagp);
                    mark_metapage_dirty(mp);
                }
                release_metapage(mp);

                /* free the AG lock and return.
                 */
                AG_UNLOCK(imap, agno);
                return (rc);
            }

            if (!addext)
                extno =
                    (extno ==
                     EXTSPERIAG - 1) ? 0 : extno + 1;
        }

        /*
         * no free inodes within the extent containing the hint.
         *
         * try to allocate from the backed extents following
         * hint or, if appropriate (i.e. addext is true), allocate
         * an extent of free inodes at or following the extent
         * containing the hint.
         *
         * the free inode and free extent summary maps are used
         * here, so determine the starting summary map position
         * and the number of words we'll have to examine.  again,
         * the approach is to allocate following the hint, so we
         * might have to initially ignore prior bits of the summary
         * map that represent extents prior to the extent containing
         * the hint and later revisit these bits.
         */
        bitno = extno & (EXTSPERSUM - 1);
        nwords = (bitno == 0) ? SMAPSZ : SMAPSZ + 1;
        sword = extno >> L2EXTSPERSUM;

        /* mask any prior bits for the starting words of the
         * summary map.
         */
        mask = ONES << (EXTSPERSUM - bitno);
        inosmap = le32_to_cpu(iagp->inosmap[sword]) | mask;
        extsmap = le32_to_cpu(iagp->extsmap[sword]) | mask;

        /* scan the free inode and free extent summary maps for
         * free resources.
         */
        for (i = 0; i < nwords; i++) {
            /* check if this word of the free inode summary
             * map describes an extent with free inodes.
             */
            if (~inosmap) {
                /* an extent with free inodes has been
                 * found. determine the extent number
                 * and the inode number within the extent.
                 */
                rem = diFindFree(inosmap, 0);
                extno = (sword << L2EXTSPERSUM) + rem;
                rem = diFindFree(le32_to_cpu(iagp->wmap[extno]),
                         0);
                if (rem >= INOSPEREXT) {
                    IREAD_UNLOCK(ipimap);
                    release_metapage(mp);
                    AG_UNLOCK(imap, agno);
                    jfs_error(ip->i_sb,
                          "diAlloc: can't find free bit "
                          "in wmap");
                    return -EIO;
                }

                /* determine the inode number within the
                 * iag and allocate the inode from the
                 * map.
                 */
                ino = (extno << L2INOSPEREXT) + rem;
                rc = diAllocBit(imap, iagp, ino);
                IREAD_UNLOCK(ipimap);
                if (rc)
                    assert(rc == -EIO);
                else {
                    /* set the results of the allocation
                     * and write the iag.
                     */
                    diInitInode(ip, iagno, ino, extno,
                            iagp);
                    mark_metapage_dirty(mp);
                }
                release_metapage(mp);

                /* free the AG lock and return.
                 */
                AG_UNLOCK(imap, agno);
                return (rc);

            }

            /* check if we may allocate an extent of free
             * inodes and whether this word of the free
             * extents summary map describes a free extent.
             */
            if (addext && ~extsmap) {
                /* a free extent has been found.  determine
                 * the extent number.
                 */
                rem = diFindFree(extsmap, 0);
                extno = (sword << L2EXTSPERSUM) + rem;

                /* allocate an extent of free inodes.
                 */
                if ((rc = diNewExt(imap, iagp, extno))) {
                    /* if there is no disk space for a
                     * new extent, try to allocate the
                     * disk inode from somewhere else.
                     */
                    if (rc == -ENOSPC)
                        break;

                    assert(rc == -EIO);
                } else {
                    /* set the results of the allocation
                     * and write the iag.
                     */
                    diInitInode(ip, iagno,
                            extno << L2INOSPEREXT,
                            extno, iagp);
                    mark_metapage_dirty(mp);
                }
                release_metapage(mp);
                /* free the imap inode & the AG lock & return.
                 */
                IREAD_UNLOCK(ipimap);
                AG_UNLOCK(imap, agno);
                return (rc);
            }

            /* move on to the next set of summary map words.
             */
            sword = (sword == SMAPSZ - 1) ? 0 : sword + 1;
            inosmap = le32_to_cpu(iagp->inosmap[sword]);
            extsmap = le32_to_cpu(iagp->extsmap[sword]);
        }
    }
    /* unlock imap inode */
    IREAD_UNLOCK(ipimap);

    /* nothing doing in this iag, so release it. */
    release_metapage(mp);

      tryag:
    /*
     * try to allocate anywhere within the same AG as the parent inode.
     */
    rc = diAllocAG(imap, agno, dir, ip);

    AG_UNLOCK(imap, agno);

    if (rc != -ENOSPC)
        return (rc);

    /*
     * try to allocate in any AG.
     */
    return (diAllocAny(imap, agno, dir, ip));
}


/*
 * NAME:    diAllocAG(imap,agno,dir,ip)
 *
 * FUNCTION:    allocate a disk inode from the allocation group.
 *
 *      this routine first determines if a new extent of free
 *      inodes should be added for the allocation group, with
 *      the current request satisfied from this extent. if this
 *      is the case, an attempt will be made to do just that.  if
 *      this attempt fails or it has been determined that a new
 *      extent should not be added, an attempt is made to satisfy
 *      the request by allocating an existing (backed) free inode
 *      from the allocation group.
 *
 * PRE CONDITION: Already have the AG lock for this AG.
 *
 * PARAMETERS:
 *  imap    - pointer to inode map control structure.
 *  agno    - allocation group to allocate from.
 *  dir - 'true' if the new disk inode is for a directory.
 *  ip  - pointer to the new inode to be filled in on successful return
 *        with the disk inode number allocated, its extent address
 *        and the start of the ag.
 *
 * RETURN VALUES:
 *  0   - success.
 *  -ENOSPC - insufficient disk resources.
 *  -EIO    - i/o error.
 */
static int
diAllocAG(struct inomap * imap, int agno, bool dir, struct inode *ip)
{
    int rc, addext, numfree, numinos;

    /* get the number of free and the number of backed disk
     * inodes currently within the ag.
     */
    numfree = imap->im_agctl[agno].numfree;
    numinos = imap->im_agctl[agno].numinos;

    if (numfree > numinos) {
        jfs_error(ip->i_sb, "diAllocAG: numfree > numinos");
        return -EIO;
    }

    /* determine if we should allocate a new extent of free inodes
     * within the ag: for directory inodes, add a new extent
     * if there are a small number of free inodes or number of free
     * inodes is a small percentage of the number of backed inodes.
     */
    if (dir)
        addext = (numfree < 64 ||
              (numfree < 256
               && ((numfree * 100) / numinos) <= 20));
    else
        addext = (numfree == 0);

    /*
     * try to allocate a new extent of free inodes.
     */
    if (addext) {
        /* if free space is not available for this new extent, try
         * below to allocate a free and existing (already backed)
         * inode from the ag.
         */
        if ((rc = diAllocExt(imap, agno, ip)) != -ENOSPC)
            return (rc);
    }

    /*
     * try to allocate an existing free inode from the ag.
     */
    return (diAllocIno(imap, agno, ip));
}


/*
 * NAME:    diAllocAny(imap,agno,dir,iap)
 *
 * FUNCTION:    allocate a disk inode from any other allocation group.
 *
 *      this routine is called when an allocation attempt within
 *      the primary allocation group has failed. if attempts to
 *      allocate an inode from any allocation group other than the
 *      specified primary group.
 *
 * PARAMETERS:
 *  imap    - pointer to inode map control structure.
 *  agno    - primary allocation group (to avoid).
 *  dir - 'true' if the new disk inode is for a directory.
 *  ip  - pointer to a new inode to be filled in on successful return
 *        with the disk inode number allocated, its extent address
 *        and the start of the ag.
 *
 * RETURN VALUES:
 *  0   - success.
 *  -ENOSPC - insufficient disk resources.
 *  -EIO    - i/o error.
 */
static int
diAllocAny(struct inomap * imap, int agno, bool dir, struct inode *ip)
{
    int ag, rc;
    int maxag = JFS_SBI(imap->im_ipimap->i_sb)->bmap->db_maxag;


    /* try to allocate from the ags following agno up to
     * the maximum ag number.
     */
    for (ag = agno + 1; ag <= maxag; ag++) {
        AG_LOCK(imap, ag);

        rc = diAllocAG(imap, ag, dir, ip);

        AG_UNLOCK(imap, ag);

        if (rc != -ENOSPC)
            return (rc);
    }

    /* try to allocate from the ags in front of agno.
     */
    for (ag = 0; ag < agno; ag++) {
        AG_LOCK(imap, ag);

        rc = diAllocAG(imap, ag, dir, ip);

        AG_UNLOCK(imap, ag);

        if (rc != -ENOSPC)
            return (rc);
    }

    /* no free disk inodes.
     */
    return -ENOSPC;
}


/*
 * NAME:    diAllocIno(imap,agno,ip)
 *
 * FUNCTION:    allocate a disk inode from the allocation group's free
 *      inode list, returning an error if this free list is
 *      empty (i.e. no iags on the list).
 *
 *      allocation occurs from the first iag on the list using
 *      the iag's free inode summary map to find the leftmost
 *      free inode in the iag.
 *
 * PRE CONDITION: Already have AG lock for this AG.
 *
 * PARAMETERS:
 *  imap    - pointer to inode map control structure.
 *  agno    - allocation group.
 *  ip  - pointer to new inode to be filled in on successful return
 *        with the disk inode number allocated, its extent address
 *        and the start of the ag.
 *
 * RETURN VALUES:
 *  0   - success.
 *  -ENOSPC - insufficient disk resources.
 *  -EIO    - i/o error.
 */
static int diAllocIno(struct inomap * imap, int agno, struct inode *ip)
{
    int iagno, ino, rc, rem, extno, sword;
    struct metapage *mp;
    struct iag *iagp;

    /* check if there are iags on the ag's free inode list.
     */
    if ((iagno = imap->im_agctl[agno].inofree) < 0)
        return -ENOSPC;

    /* obtain read lock on imap inode */
    IREAD_LOCK(imap->im_ipimap, RDWRLOCK_IMAP);

    /* read the iag at the head of the list.
     */
    if ((rc = diIAGRead(imap, iagno, &mp))) {
        IREAD_UNLOCK(imap->im_ipimap);
        return (rc);
    }
    iagp = (struct iag *) mp->data;

    /* better be free inodes in this iag if it is on the
     * list.
     */
    if (!iagp->nfreeinos) {
        IREAD_UNLOCK(imap->im_ipimap);
        release_metapage(mp);
        jfs_error(ip->i_sb,
              "diAllocIno: nfreeinos = 0, but iag on freelist");
        return -EIO;
    }

    /* scan the free inode summary map to find an extent
     * with free inodes.
     */
    for (sword = 0;; sword++) {
        if (sword >= SMAPSZ) {
            IREAD_UNLOCK(imap->im_ipimap);
            release_metapage(mp);
            jfs_error(ip->i_sb,
                  "diAllocIno: free inode not found in summary map");
            return -EIO;
        }

        if (~iagp->inosmap[sword])
            break;
    }

    /* found a extent with free inodes. determine
     * the extent number.
     */
    rem = diFindFree(le32_to_cpu(iagp->inosmap[sword]), 0);
    if (rem >= EXTSPERSUM) {
        IREAD_UNLOCK(imap->im_ipimap);
        release_metapage(mp);
        jfs_error(ip->i_sb, "diAllocIno: no free extent found");
        return -EIO;
    }
    extno = (sword << L2EXTSPERSUM) + rem;

    /* find the first free inode in the extent.
     */
    rem = diFindFree(le32_to_cpu(iagp->wmap[extno]), 0);
    if (rem >= INOSPEREXT) {
        IREAD_UNLOCK(imap->im_ipimap);
        release_metapage(mp);
        jfs_error(ip->i_sb, "diAllocIno: free inode not found");
        return -EIO;
    }

    /* compute the inode number within the iag.
     */
    ino = (extno << L2INOSPEREXT) + rem;

    /* allocate the inode.
     */
    rc = diAllocBit(imap, iagp, ino);
    IREAD_UNLOCK(imap->im_ipimap);
    if (rc) {
        release_metapage(mp);
        return (rc);
    }

    /* set the results of the allocation and write the iag.
     */
    diInitInode(ip, iagno, ino, extno, iagp);
    write_metapage(mp);

    return (0);
}


/*
 * NAME:    diAllocExt(imap,agno,ip)
 *
 * FUNCTION:    add a new extent of free inodes to an iag, allocating
 *      an inode from this extent to satisfy the current allocation
 *      request.
 *
 *      this routine first tries to find an existing iag with free
 *      extents through the ag free extent list.  if list is not
 *      empty, the head of the list will be selected as the home
 *      of the new extent of free inodes.  otherwise (the list is
 *      empty), a new iag will be allocated for the ag to contain
 *      the extent.
 *
 *      once an iag has been selected, the free extent summary map
 *      is used to locate a free extent within the iag and diNewExt()
 *      is called to initialize the extent, with initialization
 *      including the allocation of the first inode of the extent
 *      for the purpose of satisfying this request.
 *
 * PARAMETERS:
 *  imap    - pointer to inode map control structure.
 *  agno    - allocation group number.
 *  ip  - pointer to new inode to be filled in on successful return
 *        with the disk inode number allocated, its extent address
 *        and the start of the ag.
 *
 * RETURN VALUES:
 *  0   - success.
 *  -ENOSPC - insufficient disk resources.
 *  -EIO    - i/o error.
 */
static int diAllocExt(struct inomap * imap, int agno, struct inode *ip)
{
    int rem, iagno, sword, extno, rc;
    struct metapage *mp;
    struct iag *iagp;

    /* check if the ag has any iags with free extents.  if not,
     * allocate a new iag for the ag.
     */
    if ((iagno = imap->im_agctl[agno].extfree) < 0) {
        /* If successful, diNewIAG will obtain the read lock on the
         * imap inode.
         */
        if ((rc = diNewIAG(imap, &iagno, agno, &mp))) {
            return (rc);
        }
        iagp = (struct iag *) mp->data;

        /* set the ag number if this a brand new iag
         */
        iagp->agstart =
            cpu_to_le64(AGTOBLK(agno, imap->im_ipimap));
    } else {
        /* read the iag.
         */
        IREAD_LOCK(imap->im_ipimap, RDWRLOCK_IMAP);
        if ((rc = diIAGRead(imap, iagno, &mp))) {
            IREAD_UNLOCK(imap->im_ipimap);
            jfs_error(ip->i_sb, "diAllocExt: error reading iag");
            return rc;
        }
        iagp = (struct iag *) mp->data;
    }

    /* using the free extent summary map, find a free extent.
     */
    for (sword = 0;; sword++) {
        if (sword >= SMAPSZ) {
            release_metapage(mp);
            IREAD_UNLOCK(imap->im_ipimap);
            jfs_error(ip->i_sb,
                  "diAllocExt: free ext summary map not found");
            return -EIO;
        }
        if (~iagp->extsmap[sword])
            break;
    }

    /* determine the extent number of the free extent.
     */
    rem = diFindFree(le32_to_cpu(iagp->extsmap[sword]), 0);
    if (rem >= EXTSPERSUM) {
        release_metapage(mp);
        IREAD_UNLOCK(imap->im_ipimap);
        jfs_error(ip->i_sb, "diAllocExt: free extent not found");
        return -EIO;
    }
    extno = (sword << L2EXTSPERSUM) + rem;

    /* initialize the new extent.
     */
    rc = diNewExt(imap, iagp, extno);
    IREAD_UNLOCK(imap->im_ipimap);
    if (rc) {
        /* something bad happened.  if a new iag was allocated,
         * place it back on the inode map's iag free list, and
         * clear the ag number information.
         */
        if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
            IAGFREE_LOCK(imap);
            iagp->iagfree = cpu_to_le32(imap->im_freeiag);
            imap->im_freeiag = iagno;
            IAGFREE_UNLOCK(imap);
        }
        write_metapage(mp);
        return (rc);
    }

    /* set the results of the allocation and write the iag.
     */
    diInitInode(ip, iagno, extno << L2INOSPEREXT, extno, iagp);

    write_metapage(mp);

    return (0);
}


/*
 * NAME:    diAllocBit(imap,iagp,ino)
 *
 * FUNCTION:    allocate a backed inode from an iag.
 *
 *      this routine performs the mechanics of allocating a
 *      specified inode from a backed extent.
 *
 *      if the inode to be allocated represents the last free
 *      inode within the iag, the iag will be removed from the
 *      ag free inode list.
 *
 *      a careful update approach is used to provide consistency
 *      in the face of updates to multiple buffers.  under this
 *      approach, all required buffers are obtained before making
 *      any updates and are held all are updates are complete.
 *
 * PRE CONDITION: Already have buffer lock on iagp.  Already have AG lock on
 *  this AG.  Must have read lock on imap inode.
 *
 * PARAMETERS:
 *  imap    - pointer to inode map control structure.
 *  iagp    - pointer to iag.
 *  ino - inode number to be allocated within the iag.
 *
 * RETURN VALUES:
 *  0   - success.
 *  -ENOSPC - insufficient disk resources.
 *  -EIO    - i/o error.
 */
static int diAllocBit(struct inomap * imap, struct iag * iagp, int ino)
{
    int extno, bitno, agno, sword, rc;
    struct metapage *amp = NULL, *bmp = NULL;
    struct iag *aiagp = NULL, *biagp = NULL;
    u32 mask;

    /* check if this is the last free inode within the iag.
     * if so, it will have to be removed from the ag free
     * inode list, so get the iags preceding and following
     * it on the list.
     */
    if (iagp->nfreeinos == cpu_to_le32(1)) {
        if ((int) le32_to_cpu(iagp->inofreefwd) >= 0) {
            if ((rc =
                 diIAGRead(imap, le32_to_cpu(iagp->inofreefwd),
                       &amp)))
                return (rc);
            aiagp = (struct iag *) amp->data;
        }

        if ((int) le32_to_cpu(iagp->inofreeback) >= 0) {
            if ((rc =
                 diIAGRead(imap,
                       le32_to_cpu(iagp->inofreeback),
                       &bmp))) {
                if (amp)
                    release_metapage(amp);
                return (rc);
            }
            biagp = (struct iag *) bmp->data;
        }
    }

    /* get the ag number, extent number, inode number within
     * the extent.
     */
    agno = BLKTOAG(le64_to_cpu(iagp->agstart), JFS_SBI(imap->im_ipimap->i_sb));
    extno = ino >> L2INOSPEREXT;
    bitno = ino & (INOSPEREXT - 1);

    /* compute the mask for setting the map.
     */
    mask = HIGHORDER >> bitno;

    /* the inode should be free and backed.
     */
    if (((le32_to_cpu(iagp->pmap[extno]) & mask) != 0) ||
        ((le32_to_cpu(iagp->wmap[extno]) & mask) != 0) ||
        (addressPXD(&iagp->inoext[extno]) == 0)) {
        if (amp)
            release_metapage(amp);
        if (bmp)
            release_metapage(bmp);

        jfs_error(imap->im_ipimap->i_sb,
              "diAllocBit: iag inconsistent");
        return -EIO;
    }

    /* mark the inode as allocated in the working map.
     */
    iagp->wmap[extno] |= cpu_to_le32(mask);

    /* check if all inodes within the extent are now
     * allocated.  if so, update the free inode summary
     * map to reflect this.
     */
    if (iagp->wmap[extno] == cpu_to_le32(ONES)) {
        sword = extno >> L2EXTSPERSUM;
        bitno = extno & (EXTSPERSUM - 1);
        iagp->inosmap[sword] |= cpu_to_le32(HIGHORDER >> bitno);
    }

    /* if this was the last free inode in the iag, remove the
     * iag from the ag free inode list.
     */
    if (iagp->nfreeinos == cpu_to_le32(1)) {
        if (amp) {
            aiagp->inofreeback = iagp->inofreeback;
            write_metapage(amp);
        }

        if (bmp) {
            biagp->inofreefwd = iagp->inofreefwd;
            write_metapage(bmp);
        } else {
            imap->im_agctl[agno].inofree =
                le32_to_cpu(iagp->inofreefwd);
        }
        iagp->inofreefwd = iagp->inofreeback = cpu_to_le32(-1);
    }

    /* update the free inode count at the iag, ag, inode
     * map levels.
     */
    le32_add_cpu(&iagp->nfreeinos, -1);
    imap->im_agctl[agno].numfree -= 1;
    atomic_dec(&imap->im_numfree);

    return (0);
}


/*
 * NAME:    diNewExt(imap,iagp,extno)
 *
 * FUNCTION:    initialize a new extent of inodes for an iag, allocating
 *      the first inode of the extent for use for the current
 *      allocation request.
 *
 *      disk resources are allocated for the new extent of inodes
 *      and the inodes themselves are initialized to reflect their
 *      existence within the extent (i.e. their inode numbers and
 *      inode extent addresses are set) and their initial state
 *      (mode and link count are set to zero).
 *
 *      if the iag is new, it is not yet on an ag extent free list
 *      but will now be placed on this list.
 *
 *      if the allocation of the new extent causes the iag to
 *      have no free extent, the iag will be removed from the
 *      ag extent free list.
 *
 *      if the iag has no free backed inodes, it will be placed
 *      on the ag free inode list, since the addition of the new
 *      extent will now cause it to have free inodes.
 *
 *      a careful update approach is used to provide consistency
 *      (i.e. list consistency) in the face of updates to multiple
 *      buffers.  under this approach, all required buffers are
 *      obtained before making any updates and are held until all
 *      updates are complete.
 *
 * PRE CONDITION: Already have buffer lock on iagp.  Already have AG lock on
 *  this AG.  Must have read lock on imap inode.
 *
 * PARAMETERS:
 *  imap    - pointer to inode map control structure.
 *  iagp    - pointer to iag.
 *  extno   - extent number.
 *
 * RETURN VALUES:
 *  0   - success.
 *  -ENOSPC - insufficient disk resources.
 *  -EIO    - i/o error.
 */
static int diNewExt(struct inomap * imap, struct iag * iagp, int extno)
{
    int agno, iagno, fwd, back, freei = 0, sword, rc;
    struct iag *aiagp = NULL, *biagp = NULL, *ciagp = NULL;
    struct metapage *amp, *bmp, *cmp, *dmp;
    struct inode *ipimap;
    s64 blkno, hint;
    int i, j;
    u32 mask;
    ino_t ino;
    struct dinode *dp;
    struct jfs_sb_info *sbi;

    /* better have free extents.
     */
    if (!iagp->nfreeexts) {
        jfs_error(imap->im_ipimap->i_sb, "diNewExt: no free extents");
        return -EIO;
    }

    /* get the inode map inode.
     */
    ipimap = imap->im_ipimap;
    sbi = JFS_SBI(ipimap->i_sb);

    amp = bmp = cmp = NULL;

    /* get the ag and iag numbers for this iag.
     */
    agno = BLKTOAG(le64_to_cpu(iagp->agstart), sbi);
    iagno = le32_to_cpu(iagp->iagnum);

    /* check if this is the last free extent within the
     * iag.  if so, the iag must be removed from the ag
     * free extent list, so get the iags preceding and
     * following the iag on this list.
     */
    if (iagp->nfreeexts == cpu_to_le32(1)) {
        if ((fwd = le32_to_cpu(iagp->extfreefwd)) >= 0) {
            if ((rc = diIAGRead(imap, fwd, &amp)))
                return (rc);
            aiagp = (struct iag *) amp->data;
        }

        if ((back = le32_to_cpu(iagp->extfreeback)) >= 0) {
            if ((rc = diIAGRead(imap, back, &bmp)))
                goto error_out;
            biagp = (struct iag *) bmp->data;
        }
    } else {
        /* the iag has free extents.  if all extents are free
         * (as is the case for a newly allocated iag), the iag
         * must be added to the ag free extent list, so get
         * the iag at the head of the list in preparation for
         * adding this iag to this list.
         */
        fwd = back = -1;
        if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
            if ((fwd = imap->im_agctl[agno].extfree) >= 0) {
                if ((rc = diIAGRead(imap, fwd, &amp)))
                    goto error_out;
                aiagp = (struct iag *) amp->data;
            }
        }
    }

    /* check if the iag has no free inodes.  if so, the iag
     * will have to be added to the ag free inode list, so get
     * the iag at the head of the list in preparation for
     * adding this iag to this list.  in doing this, we must
     * check if we already have the iag at the head of
     * the list in hand.
     */
    if (iagp->nfreeinos == 0) {
        freei = imap->im_agctl[agno].inofree;

        if (freei >= 0) {
            if (freei == fwd) {
                ciagp = aiagp;
            } else if (freei == back) {
                ciagp = biagp;
            } else {
                if ((rc = diIAGRead(imap, freei, &cmp)))
                    goto error_out;
                ciagp = (struct iag *) cmp->data;
            }
            if (ciagp == NULL) {
                jfs_error(imap->im_ipimap->i_sb,
                      "diNewExt: ciagp == NULL");
                rc = -EIO;
                goto error_out;
            }
        }
    }

    /* allocate disk space for the inode extent.
     */
    if ((extno == 0) || (addressPXD(&iagp->inoext[extno - 1]) == 0))
        hint = ((s64) agno << sbi->bmap->db_agl2size) - 1;
    else
        hint = addressPXD(&iagp->inoext[extno - 1]) +
            lengthPXD(&iagp->inoext[extno - 1]) - 1;

    if ((rc = dbAlloc(ipimap, hint, (s64) imap->im_nbperiext, &blkno)))
        goto error_out;

    /* compute the inode number of the first inode within the
     * extent.
     */
    ino = (iagno << L2INOSPERIAG) + (extno << L2INOSPEREXT);

    /* initialize the inodes within the newly allocated extent a
     * page at a time.
     */
    for (i = 0; i < imap->im_nbperiext; i += sbi->nbperpage) {
        /* get a buffer for this page of disk inodes.
         */
        dmp = get_metapage(ipimap, blkno + i, PSIZE, 1);
        if (dmp == NULL) {
            rc = -EIO;
            goto error_out;
        }
        dp = (struct dinode *) dmp->data;

        /* initialize the inode number, mode, link count and
         * inode extent address.
         */
        for (j = 0; j < INOSPERPAGE; j++, dp++, ino++) {
            dp->di_inostamp = cpu_to_le32(sbi->inostamp);
            dp->di_number = cpu_to_le32(ino);
            dp->di_fileset = cpu_to_le32(FILESYSTEM_I);
            dp->di_mode = 0;
            dp->di_nlink = 0;
            PXDaddress(&(dp->di_ixpxd), blkno);
            PXDlength(&(dp->di_ixpxd), imap->im_nbperiext);
        }
        write_metapage(dmp);
    }

    /* if this is the last free extent within the iag, remove the
     * iag from the ag free extent list.
     */
    if (iagp->nfreeexts == cpu_to_le32(1)) {
        if (fwd >= 0)
            aiagp->extfreeback = iagp->extfreeback;

        if (back >= 0)
            biagp->extfreefwd = iagp->extfreefwd;
        else
            imap->im_agctl[agno].extfree =
                le32_to_cpu(iagp->extfreefwd);

        iagp->extfreefwd = iagp->extfreeback = cpu_to_le32(-1);
    } else {
        /* if the iag has all free extents (newly allocated iag),
         * add the iag to the ag free extent list.
         */
        if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
            if (fwd >= 0)
                aiagp->extfreeback = cpu_to_le32(iagno);

            iagp->extfreefwd = cpu_to_le32(fwd);
            iagp->extfreeback = cpu_to_le32(-1);
            imap->im_agctl[agno].extfree = iagno;
        }
    }

    /* if the iag has no free inodes, add the iag to the
     * ag free inode list.
     */
    if (iagp->nfreeinos == 0) {
        if (freei >= 0)
            ciagp->inofreeback = cpu_to_le32(iagno);

        iagp->inofreefwd =
            cpu_to_le32(imap->im_agctl[agno].inofree);
        iagp->inofreeback = cpu_to_le32(-1);
        imap->im_agctl[agno].inofree = iagno;
    }

    /* initialize the extent descriptor of the extent. */
    PXDlength(&iagp->inoext[extno], imap->im_nbperiext);
    PXDaddress(&iagp->inoext[extno], blkno);

    /* initialize the working and persistent map of the extent.
     * the working map will be initialized such that
     * it indicates the first inode of the extent is allocated.
     */
    iagp->wmap[extno] = cpu_to_le32(HIGHORDER);
    iagp->pmap[extno] = 0;

    /* update the free inode and free extent summary maps
     * for the extent to indicate the extent has free inodes
     * and no longer represents a free extent.
     */
    sword = extno >> L2EXTSPERSUM;
    mask = HIGHORDER >> (extno & (EXTSPERSUM - 1));
    iagp->extsmap[sword] |= cpu_to_le32(mask);
    iagp->inosmap[sword] &= cpu_to_le32(~mask);

    /* update the free inode and free extent counts for the
     * iag.
     */
    le32_add_cpu(&iagp->nfreeinos, (INOSPEREXT - 1));
    le32_add_cpu(&iagp->nfreeexts, -1);

    /* update the free and backed inode counts for the ag.
     */
    imap->im_agctl[agno].numfree += (INOSPEREXT - 1);
    imap->im_agctl[agno].numinos += INOSPEREXT;

    /* update the free and backed inode counts for the inode map.
     */
    atomic_add(INOSPEREXT - 1, &imap->im_numfree);
    atomic_add(INOSPEREXT, &imap->im_numinos);

    /* write the iags.
     */
    if (amp)
        write_metapage(amp);
    if (bmp)
        write_metapage(bmp);
    if (cmp)
        write_metapage(cmp);

    return (0);

      error_out:

    /* release the iags.
     */
    if (amp)
        release_metapage(amp);
    if (bmp)
        release_metapage(bmp);
    if (cmp)
        release_metapage(cmp);

    return (rc);
}


/*
 * NAME:    diNewIAG(imap,iagnop,agno)
 *
 * FUNCTION:    allocate a new iag for an allocation group.
 *
 *      first tries to allocate the iag from the inode map
 *      iagfree list:
 *      if the list has free iags, the head of the list is removed
 *      and returned to satisfy the request.
 *      if the inode map's iag free list is empty, the inode map
 *      is extended to hold a new iag. this new iag is initialized
 *      and returned to satisfy the request.
 *
 * PARAMETERS:
 *  imap    - pointer to inode map control structure.
 *  iagnop  - pointer to an iag number set with the number of the
 *        newly allocated iag upon successful return.
 *  agno    - allocation group number.
 *  bpp - Buffer pointer to be filled in with new IAG's buffer
 *
 * RETURN VALUES:
 *  0   - success.
 *  -ENOSPC - insufficient disk resources.
 *  -EIO    - i/o error.
 *
 * serialization:
 *  AG lock held on entry/exit;
 *  write lock on the map is held inside;
 *  read lock on the map is held on successful completion;
 *
 * note: new iag transaction:
 * . synchronously write iag;
 * . write log of xtree and inode of imap;
 * . commit;
 * . synchronous write of xtree (right to left, bottom to top);
 * . at start of logredo(): init in-memory imap with one additional iag page;
 * . at end of logredo(): re-read imap inode to determine
 *   new imap size;
 */
static int
diNewIAG(struct inomap * imap, int *iagnop, int agno, struct metapage ** mpp)
{
    int rc;
    int iagno, i, xlen;
    struct inode *ipimap;
    struct super_block *sb;
    struct jfs_sb_info *sbi;
    struct metapage *mp;
    struct iag *iagp;
    s64 xaddr = 0;
    s64 blkno;
    tid_t tid;
    struct inode *iplist[1];

    /* pick up pointers to the inode map and mount inodes */
    ipimap = imap->im_ipimap;
    sb = ipimap->i_sb;
    sbi = JFS_SBI(sb);

    /* acquire the free iag lock */
    IAGFREE_LOCK(imap);

    /* if there are any iags on the inode map free iag list,
     * allocate the iag from the head of the list.
     */
    if (imap->im_freeiag >= 0) {
        /* pick up the iag number at the head of the list */
        iagno = imap->im_freeiag;

        /* determine the logical block number of the iag */
        blkno = IAGTOLBLK(iagno, sbi->l2nbperpage);
    } else {
        /* no free iags. the inode map will have to be extented
         * to include a new iag.
         */

        /* acquire inode map lock */
        IWRITE_LOCK(ipimap, RDWRLOCK_IMAP);

        if (ipimap->i_size >> L2PSIZE != imap->im_nextiag + 1) {
            IWRITE_UNLOCK(ipimap);
            IAGFREE_UNLOCK(imap);
            jfs_error(imap->im_ipimap->i_sb,
                  "diNewIAG: ipimap->i_size is wrong");
            return -EIO;
        }


        /* get the next available iag number */
        iagno = imap->im_nextiag;

        /* make sure that we have not exceeded the maximum inode
         * number limit.
         */
        if (iagno > (MAXIAGS - 1)) {
            /* release the inode map lock */
            IWRITE_UNLOCK(ipimap);

            rc = -ENOSPC;
            goto out;
        }

        /*
         * synchronously append new iag page.
         */
        /* determine the logical address of iag page to append */
        blkno = IAGTOLBLK(iagno, sbi->l2nbperpage);

        /* Allocate extent for new iag page */
        xlen = sbi->nbperpage;
        if ((rc = dbAlloc(ipimap, 0, (s64) xlen, &xaddr))) {
            /* release the inode map lock */
            IWRITE_UNLOCK(ipimap);

            goto out;
        }

        /*
         * start transaction of update of the inode map
         * addressing structure pointing to the new iag page;
         */
        tid = txBegin(sb, COMMIT_FORCE);
        mutex_lock(&JFS_IP(ipimap)->commit_mutex);

        /* update the inode map addressing structure to point to it */
        if ((rc =
             xtInsert(tid, ipimap, 0, blkno, xlen, &xaddr, 0))) {
            txEnd(tid);
            mutex_unlock(&JFS_IP(ipimap)->commit_mutex);
            /* Free the blocks allocated for the iag since it was
             * not successfully added to the inode map
             */
            dbFree(ipimap, xaddr, (s64) xlen);

            /* release the inode map lock */
            IWRITE_UNLOCK(ipimap);

            goto out;
        }

        /* update the inode map's inode to reflect the extension */
        ipimap->i_size += PSIZE;
        inode_add_bytes(ipimap, PSIZE);

        /* assign a buffer for the page */
        mp = get_metapage(ipimap, blkno, PSIZE, 0);
        if (!mp) {
            /*
             * This is very unlikely since we just created the
             * extent, but let's try to handle it correctly
             */
            xtTruncate(tid, ipimap, ipimap->i_size - PSIZE,
                   COMMIT_PWMAP);

            txAbort(tid, 0);
            txEnd(tid);
            mutex_unlock(&JFS_IP(ipimap)->commit_mutex);

            /* release the inode map lock */
            IWRITE_UNLOCK(ipimap);

            rc = -EIO;
            goto out;
        }
        iagp = (struct iag *) mp->data;

        /* init the iag */
        memset(iagp, 0, sizeof(struct iag));
        iagp->iagnum = cpu_to_le32(iagno);
        iagp->inofreefwd = iagp->inofreeback = cpu_to_le32(-1);
        iagp->extfreefwd = iagp->extfreeback = cpu_to_le32(-1);
        iagp->iagfree = cpu_to_le32(-1);
        iagp->nfreeinos = 0;
        iagp->nfreeexts = cpu_to_le32(EXTSPERIAG);

        /* initialize the free inode summary map (free extent
         * summary map initialization handled by bzero).
         */
        for (i = 0; i < SMAPSZ; i++)
            iagp->inosmap[i] = cpu_to_le32(ONES);

        /*
         * Write and sync the metapage
         */
        flush_metapage(mp);

        /*
         * txCommit(COMMIT_FORCE) will synchronously write address
         * index pages and inode after commit in careful update order
         * of address index pages (right to left, bottom up);
         */
        iplist[0] = ipimap;
        rc = txCommit(tid, 1, &iplist[0], COMMIT_FORCE);

        txEnd(tid);
        mutex_unlock(&JFS_IP(ipimap)->commit_mutex);

        duplicateIXtree(sb, blkno, xlen, &xaddr);

        /* update the next available iag number */
        imap->im_nextiag += 1;

        /* Add the iag to the iag free list so we don't lose the iag
         * if a failure happens now.
         */
        imap->im_freeiag = iagno;

        /* Until we have logredo working, we want the imap inode &
         * control page to be up to date.
         */
        diSync(ipimap);

        /* release the inode map lock */
        IWRITE_UNLOCK(ipimap);
    }

    /* obtain read lock on map */
    IREAD_LOCK(ipimap, RDWRLOCK_IMAP);

    /* read the iag */
    if ((rc = diIAGRead(imap, iagno, &mp))) {
        IREAD_UNLOCK(ipimap);
        rc = -EIO;
        goto out;
    }
    iagp = (struct iag *) mp->data;

    /* remove the iag from the iag free list */
    imap->im_freeiag = le32_to_cpu(iagp->iagfree);
    iagp->iagfree = cpu_to_le32(-1);

    /* set the return iag number and buffer pointer */
    *iagnop = iagno;
    *mpp = mp;

      out:
    /* release the iag free lock */
    IAGFREE_UNLOCK(imap);

    return (rc);
}

/*
 * NAME:    diIAGRead()
 *
 * FUNCTION:    get the buffer for the specified iag within a fileset
 *      or aggregate inode map.
 *
 * PARAMETERS:
 *  imap    - pointer to inode map control structure.
 *  iagno   - iag number.
 *  bpp - point to buffer pointer to be filled in on successful
 *        exit.
 *
 * SERIALIZATION:
 *  must have read lock on imap inode
 *  (When called by diExtendFS, the filesystem is quiesced, therefore
 *   the read lock is unnecessary.)
 *
 * RETURN VALUES:
 *  0   - success.
 *  -EIO    - i/o error.
 */
static int diIAGRead(struct inomap * imap, int iagno, struct metapage ** mpp)
{
    struct inode *ipimap = imap->im_ipimap;
    s64 blkno;

    /* compute the logical block number of the iag. */
    blkno = IAGTOLBLK(iagno, JFS_SBI(ipimap->i_sb)->l2nbperpage);

    /* read the iag. */
    *mpp = read_metapage(ipimap, blkno, PSIZE, 0);
    if (*mpp == NULL) {
        return -EIO;
    }

    return (0);
}

/*
 * NAME:    diFindFree()
 *
 * FUNCTION:    find the first free bit in a word starting at
 *      the specified bit position.
 *
 * PARAMETERS:
 *  word    - word to be examined.
 *  start   - starting bit position.
 *
 * RETURN VALUES:
 *  bit position of first free bit in the word or 32 if
 *  no free bits were found.
 */
static int diFindFree(u32 word, int start)
{
    int bitno;
    assert(start < 32);
    /* scan the word for the first free bit. */
    for (word <<= start, bitno = start; bitno < 32;
         bitno++, word <<= 1) {
        if ((word & HIGHORDER) == 0)
            break;
    }
    return (bitno);
}

/*
 * NAME:    diUpdatePMap()
 *
 * FUNCTION: Update the persistent map in an IAG for the allocation or
 *  freeing of the specified inode.
 *
 * PRE CONDITIONS: Working map has already been updated for allocate.
 *
 * PARAMETERS:
 *  ipimap  - Incore inode map inode
 *  inum    - Number of inode to mark in permanent map
 *  is_free - If 'true' indicates inode should be marked freed, otherwise
 *        indicates inode should be marked allocated.
 *
 * RETURN VALUES:
 *      0 for success
 */
int
diUpdatePMap(struct inode *ipimap,
         unsigned long inum, bool is_free, struct tblock * tblk)
{
    int rc;
    struct iag *iagp;
    struct metapage *mp;
    int iagno, ino, extno, bitno;
    struct inomap *imap;
    u32 mask;
    struct jfs_log *log;
    int lsn, difft, diffp;
    unsigned long flags;

    imap = JFS_IP(ipimap)->i_imap;
    /* get the iag number containing the inode */
    iagno = INOTOIAG(inum);
    /* make sure that the iag is contained within the map */
    if (iagno >= imap->im_nextiag) {
        jfs_error(ipimap->i_sb,
              "diUpdatePMap: the iag is outside the map");
        return -EIO;
    }
    /* read the iag */
    IREAD_LOCK(ipimap, RDWRLOCK_IMAP);
    rc = diIAGRead(imap, iagno, &mp);
    IREAD_UNLOCK(ipimap);
    if (rc)
        return (rc);
    metapage_wait_for_io(mp);
    iagp = (struct iag *) mp->data;
    /* get the inode number and extent number of the inode within
     * the iag and the inode number within the extent.
     */
    ino = inum & (INOSPERIAG - 1);
    extno = ino >> L2INOSPEREXT;
    bitno = ino & (INOSPEREXT - 1);
    mask = HIGHORDER >> bitno;
    /*
     * mark the inode free in persistent map:
     */
    if (is_free) {
        /* The inode should have been allocated both in working
         * map and in persistent map;
         * the inode will be freed from working map at the release
         * of last reference release;
         */
        if (!(le32_to_cpu(iagp->wmap[extno]) & mask)) {
            jfs_error(ipimap->i_sb,
                  "diUpdatePMap: inode %ld not marked as "
                  "allocated in wmap!", inum);
        }
        if (!(le32_to_cpu(iagp->pmap[extno]) & mask)) {
            jfs_error(ipimap->i_sb,
                  "diUpdatePMap: inode %ld not marked as "
                  "allocated in pmap!", inum);
        }
        /* update the bitmap for the extent of the freed inode */
        iagp->pmap[extno] &= cpu_to_le32(~mask);
    }
    /*
     * mark the inode allocated in persistent map:
     */
    else {
        /* The inode should be already allocated in the working map
         * and should be free in persistent map;
         */
        if (!(le32_to_cpu(iagp->wmap[extno]) & mask)) {
            release_metapage(mp);
            jfs_error(ipimap->i_sb,
                  "diUpdatePMap: the inode is not allocated in "
                  "the working map");
            return -EIO;
        }
        if ((le32_to_cpu(iagp->pmap[extno]) & mask) != 0) {
            release_metapage(mp);
            jfs_error(ipimap->i_sb,
                  "diUpdatePMap: the inode is not free in the "
                  "persistent map");
            return -EIO;
        }
        /* update the bitmap for the extent of the allocated inode */
        iagp->pmap[extno] |= cpu_to_le32(mask);
    }
    /*
     * update iag lsn
     */
    lsn = tblk->lsn;
    log = JFS_SBI(tblk->sb)->log;
    LOGSYNC_LOCK(log, flags);
    if (mp->lsn != 0) {
        /* inherit older/smaller lsn */
        logdiff(difft, lsn, log);
        logdiff(diffp, mp->lsn, log);
        if (difft < diffp) {
            mp->lsn = lsn;
            /* move mp after tblock in logsync list */
            list_move(&mp->synclist, &tblk->synclist);
        }
        /* inherit younger/larger clsn */
        assert(mp->clsn);
        logdiff(difft, tblk->clsn, log);
        logdiff(diffp, mp->clsn, log);
        if (difft > diffp)
            mp->clsn = tblk->clsn;
    } else {
        mp->log = log;
        mp->lsn = lsn;
        /* insert mp after tblock in logsync list */
        log->count++;
        list_add(&mp->synclist, &tblk->synclist);
        mp->clsn = tblk->clsn;
    }
    LOGSYNC_UNLOCK(log, flags);
    write_metapage(mp);
    return (0);
}

/*
 *  diExtendFS()
 *
 * function: update imap for extendfs();
 *
 * note: AG size has been increased s.t. each k old contiguous AGs are
 * coalesced into a new AG;
 */
int diExtendFS(struct inode *ipimap, struct inode *ipbmap)
{
    int rc, rcx = 0;
    struct inomap *imap = JFS_IP(ipimap)->i_imap;
    struct iag *iagp = NULL, *hiagp = NULL;
    struct bmap *mp = JFS_SBI(ipbmap->i_sb)->bmap;
    struct metapage *bp, *hbp;
    int i, n, head;
    int numinos, xnuminos = 0, xnumfree = 0;
    s64 agstart;

    jfs_info("diExtendFS: nextiag:%d numinos:%d numfree:%d",
           imap->im_nextiag, atomic_read(&imap->im_numinos),
           atomic_read(&imap->im_numfree));

    /*
     *  reconstruct imap
     *
     * coalesce contiguous k (newAGSize/oldAGSize) AGs;
     * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
     * note: new AG size = old AG size * (2**x).
     */

    /* init per AG control information im_agctl[] */
    for (i = 0; i < MAXAG; i++) {
        imap->im_agctl[i].inofree = -1;
        imap->im_agctl[i].extfree = -1;
        imap->im_agctl[i].numinos = 0;  /* number of backed inodes */
        imap->im_agctl[i].numfree = 0;  /* number of free backed inodes */
    }

    /*
     *  process each iag page of the map.
     *
     * rebuild AG Free Inode List, AG Free Inode Extent List;
     */
    for (i = 0; i < imap->im_nextiag; i++) {
        if ((rc = diIAGRead(imap, i, &bp))) {
            rcx = rc;
            continue;
        }
        iagp = (struct iag *) bp->data;
        if (le32_to_cpu(iagp->iagnum) != i) {
            release_metapage(bp);
            jfs_error(ipimap->i_sb,
                  "diExtendFs: unexpected value of iagnum");
            return -EIO;
        }

        /* leave free iag in the free iag list */
        if (iagp->nfreeexts == cpu_to_le32(EXTSPERIAG)) {
            release_metapage(bp);
            continue;
        }

        agstart = le64_to_cpu(iagp->agstart);
        n = agstart >> mp->db_agl2size;
        iagp->agstart = cpu_to_le64((s64)n << mp->db_agl2size);

        /* compute backed inodes */
        numinos = (EXTSPERIAG - le32_to_cpu(iagp->nfreeexts))
            << L2INOSPEREXT;
        if (numinos > 0) {
            /* merge AG backed inodes */
            imap->im_agctl[n].numinos += numinos;
            xnuminos += numinos;
        }

        /* if any backed free inodes, insert at AG free inode list */
        if ((int) le32_to_cpu(iagp->nfreeinos) > 0) {
            if ((head = imap->im_agctl[n].inofree) == -1) {
                iagp->inofreefwd = cpu_to_le32(-1);
                iagp->inofreeback = cpu_to_le32(-1);
            } else {
                if ((rc = diIAGRead(imap, head, &hbp))) {
                    rcx = rc;
                    goto nextiag;
                }
                hiagp = (struct iag *) hbp->data;
                hiagp->inofreeback = iagp->iagnum;
                iagp->inofreefwd = cpu_to_le32(head);
                iagp->inofreeback = cpu_to_le32(-1);
                write_metapage(hbp);
            }

            imap->im_agctl[n].inofree =
                le32_to_cpu(iagp->iagnum);

            /* merge AG backed free inodes */
            imap->im_agctl[n].numfree +=
                le32_to_cpu(iagp->nfreeinos);
            xnumfree += le32_to_cpu(iagp->nfreeinos);
        }

        /* if any free extents, insert at AG free extent list */
        if (le32_to_cpu(iagp->nfreeexts) > 0) {
            if ((head = imap->im_agctl[n].extfree) == -1) {
                iagp->extfreefwd = cpu_to_le32(-1);
                iagp->extfreeback = cpu_to_le32(-1);
            } else {
                if ((rc = diIAGRead(imap, head, &hbp))) {
                    rcx = rc;
                    goto nextiag;
                }
                hiagp = (struct iag *) hbp->data;
                hiagp->extfreeback = iagp->iagnum;
                iagp->extfreefwd = cpu_to_le32(head);
                iagp->extfreeback = cpu_to_le32(-1);
                write_metapage(hbp);
            }

            imap->im_agctl[n].extfree =
                le32_to_cpu(iagp->iagnum);
        }

          nextiag:
        write_metapage(bp);
    }

    if (xnuminos != atomic_read(&imap->im_numinos) ||
        xnumfree != atomic_read(&imap->im_numfree)) {
        jfs_error(ipimap->i_sb,
              "diExtendFs: numinos or numfree incorrect");
        return -EIO;
    }

    return rcx;
}


/*
 *  duplicateIXtree()
 *
 * serialization: IWRITE_LOCK held on entry/exit
 *
 * note: shadow page with regular inode (rel.2);
 */
static void duplicateIXtree(struct super_block *sb, s64 blkno,
                int xlen, s64 *xaddr)
{
    struct jfs_superblock *j_sb;
    struct buffer_head *bh;
    struct inode *ip;
    tid_t tid;

    /* if AIT2 ipmap2 is bad, do not try to update it */
    if (JFS_SBI(sb)->mntflag & JFS_BAD_SAIT)    /* s_flag */
        return;
    ip = diReadSpecial(sb, FILESYSTEM_I, 1);
    if (ip == NULL) {
        JFS_SBI(sb)->mntflag |= JFS_BAD_SAIT;
        if (readSuper(sb, &bh))
            return;
        j_sb = (struct jfs_superblock *)bh->b_data;
        j_sb->s_flag |= cpu_to_le32(JFS_BAD_SAIT);

        mark_buffer_dirty(bh);
        sync_dirty_buffer(bh);
        brelse(bh);
        return;
    }

    /* start transaction */
    tid = txBegin(sb, COMMIT_FORCE);
    /* update the inode map addressing structure to point to it */
    if (xtInsert(tid, ip, 0, blkno, xlen, xaddr, 0)) {
        JFS_SBI(sb)->mntflag |= JFS_BAD_SAIT;
        txAbort(tid, 1);
        goto cleanup;

    }
    /* update the inode map's inode to reflect the extension */
    ip->i_size += PSIZE;
    inode_add_bytes(ip, PSIZE);
    txCommit(tid, 1, &ip, COMMIT_FORCE);
      cleanup:
    txEnd(tid);
    diFreeSpecial(ip);
}

/*
 * NAME:    copy_from_dinode()
 *
 * FUNCTION:    Copies inode info from disk inode to in-memory inode
 *
 * RETURN VALUES:
 *  0   - success
 *  -ENOMEM - insufficient memory
 */
static int copy_from_dinode(struct dinode * dip, struct inode *ip)
{
    struct jfs_inode_info *jfs_ip = JFS_IP(ip);
    struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);

    jfs_ip->fileset = le32_to_cpu(dip->di_fileset);
    jfs_ip->mode2 = le32_to_cpu(dip->di_mode);
    jfs_set_inode_flags(ip);

    ip->i_mode = le32_to_cpu(dip->di_mode) & 0xffff;
    if (sbi->umask != -1) {
        ip->i_mode = (ip->i_mode & ~0777) | (0777 & ~sbi->umask);
        /* For directories, add x permission if r is allowed by umask */
        if (S_ISDIR(ip->i_mode)) {
            if (ip->i_mode & 0400)
                ip->i_mode |= 0100;
            if (ip->i_mode & 0040)
                ip->i_mode |= 0010;
            if (ip->i_mode & 0004)
                ip->i_mode |= 0001;
        }
    }
    set_nlink(ip, le32_to_cpu(dip->di_nlink));

    jfs_ip->saved_uid = make_kuid(&init_user_ns, le32_to_cpu(dip->di_uid));
    if (!uid_valid(sbi->uid))
        ip->i_uid = jfs_ip->saved_uid;
    else {
        ip->i_uid = sbi->uid;
    }

    jfs_ip->saved_gid = make_kgid(&init_user_ns, le32_to_cpu(dip->di_gid));
    if (!gid_valid(sbi->gid))
        ip->i_gid = jfs_ip->saved_gid;
    else {
        ip->i_gid = sbi->gid;
    }

    ip->i_size = le64_to_cpu(dip->di_size);
    ip->i_atime.tv_sec = le32_to_cpu(dip->di_atime.tv_sec);
    ip->i_atime.tv_nsec = le32_to_cpu(dip->di_atime.tv_nsec);
    ip->i_mtime.tv_sec = le32_to_cpu(dip->di_mtime.tv_sec);
    ip->i_mtime.tv_nsec = le32_to_cpu(dip->di_mtime.tv_nsec);
    ip->i_ctime.tv_sec = le32_to_cpu(dip->di_ctime.tv_sec);
    ip->i_ctime.tv_nsec = le32_to_cpu(dip->di_ctime.tv_nsec);
    ip->i_blocks = LBLK2PBLK(ip->i_sb, le64_to_cpu(dip->di_nblocks));
    ip->i_generation = le32_to_cpu(dip->di_gen);

    jfs_ip->ixpxd = dip->di_ixpxd;  /* in-memory pxd's are little-endian */
    jfs_ip->acl = dip->di_acl;  /* as are dxd's */
    jfs_ip->ea = dip->di_ea;
    jfs_ip->next_index = le32_to_cpu(dip->di_next_index);
    jfs_ip->otime = le32_to_cpu(dip->di_otime.tv_sec);
    jfs_ip->acltype = le32_to_cpu(dip->di_acltype);

    if (S_ISCHR(ip->i_mode) || S_ISBLK(ip->i_mode)) {
        jfs_ip->dev = le32_to_cpu(dip->di_rdev);
        ip->i_rdev = new_decode_dev(jfs_ip->dev);
    }

    if (S_ISDIR(ip->i_mode)) {
        memcpy(&jfs_ip->i_dirtable, &dip->di_dirtable, 384);
    } else if (S_ISREG(ip->i_mode) || S_ISLNK(ip->i_mode)) {
        memcpy(&jfs_ip->i_xtroot, &dip->di_xtroot, 288);
    } else
        memcpy(&jfs_ip->i_inline_ea, &dip->di_inlineea, 128);

    /* Zero the in-memory-only stuff */
    jfs_ip->cflag = 0;
    jfs_ip->btindex = 0;
    jfs_ip->btorder = 0;
    jfs_ip->bxflag = 0;
    jfs_ip->blid = 0;
    jfs_ip->atlhead = 0;
    jfs_ip->atltail = 0;
    jfs_ip->xtlid = 0;
    return (0);
}

/*
 * NAME:    copy_to_dinode()
 *
 * FUNCTION:    Copies inode info from in-memory inode to disk inode
 */
static void copy_to_dinode(struct dinode * dip, struct inode *ip)
{
    struct jfs_inode_info *jfs_ip = JFS_IP(ip);
    struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);

    dip->di_fileset = cpu_to_le32(jfs_ip->fileset);
    dip->di_inostamp = cpu_to_le32(sbi->inostamp);
    dip->di_number = cpu_to_le32(ip->i_ino);
    dip->di_gen = cpu_to_le32(ip->i_generation);
    dip->di_size = cpu_to_le64(ip->i_size);
    dip->di_nblocks = cpu_to_le64(PBLK2LBLK(ip->i_sb, ip->i_blocks));
    dip->di_nlink = cpu_to_le32(ip->i_nlink);
    if (!uid_valid(sbi->uid))
        dip->di_uid = cpu_to_le32(i_uid_read(ip));
    else
        dip->di_uid =cpu_to_le32(from_kuid(&init_user_ns,
                           jfs_ip->saved_uid));
    if (!gid_valid(sbi->gid))
        dip->di_gid = cpu_to_le32(i_gid_read(ip));
    else
        dip->di_gid = cpu_to_le32(from_kgid(&init_user_ns,
                            jfs_ip->saved_gid));
    jfs_get_inode_flags(jfs_ip);
    /*
     * mode2 is only needed for storing the higher order bits.
     * Trust i_mode for the lower order ones
     */
    if (sbi->umask == -1)
        dip->di_mode = cpu_to_le32((jfs_ip->mode2 & 0xffff0000) |
                       ip->i_mode);
    else /* Leave the original permissions alone */
        dip->di_mode = cpu_to_le32(jfs_ip->mode2);

    dip->di_atime.tv_sec = cpu_to_le32(ip->i_atime.tv_sec);
    dip->di_atime.tv_nsec = cpu_to_le32(ip->i_atime.tv_nsec);
    dip->di_ctime.tv_sec = cpu_to_le32(ip->i_ctime.tv_sec);
    dip->di_ctime.tv_nsec = cpu_to_le32(ip->i_ctime.tv_nsec);
    dip->di_mtime.tv_sec = cpu_to_le32(ip->i_mtime.tv_sec);
    dip->di_mtime.tv_nsec = cpu_to_le32(ip->i_mtime.tv_nsec);
    dip->di_ixpxd = jfs_ip->ixpxd;  /* in-memory pxd's are little-endian */
    dip->di_acl = jfs_ip->acl;  /* as are dxd's */
    dip->di_ea = jfs_ip->ea;
    dip->di_next_index = cpu_to_le32(jfs_ip->next_index);
    dip->di_otime.tv_sec = cpu_to_le32(jfs_ip->otime);
    dip->di_otime.tv_nsec = 0;
    dip->di_acltype = cpu_to_le32(jfs_ip->acltype);
    if (S_ISCHR(ip->i_mode) || S_ISBLK(ip->i_mode))
        dip->di_rdev = cpu_to_le32(jfs_ip->dev);
}