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jfs_imap.c

/*
 *   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 "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)->agno = BLKTOAG(agstart, sbi);
      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) {
            ip->i_nlink = 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 */
            ip->i_nlink = 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.
       */
      ip->i_hash.pprev = &ip->i_hash.next;

      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 = JFS_IP(ip)->agno;

      /* 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 preceeding
                   * 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 preceeding
             * 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_sb_info *sbi = JFS_SBI(ip->i_sb);
      struct jfs_inode_info *jfs_ip = JFS_IP(ip);

      ip->i_ino = (iagno << L2INOSPERIAG) + ino;
      jfs_ip->ixpxd = iagp->inoext[extno];
      jfs_ip->agno = BLKTOAG(le64_to_cpu(iagp->agstart), sbi);
      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 = JFS_IP(pip)->agno;

      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 avaliable 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 preceeding 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 preceeding 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 avaliable 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 avaliable 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 that computes to the same ag is treated as same; */
            agstart = le64_to_cpu(iagp->agstart);
            /* iagp->agstart = agstart & ~(mp->db_agsize - 1); */
            n = agstart >> 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;
            }
      }
      ip->i_nlink = le32_to_cpu(dip->di_nlink);

      jfs_ip->saved_uid = le32_to_cpu(dip->di_uid);
      if (sbi->uid == -1)
            ip->i_uid = jfs_ip->saved_uid;
      else {
            ip->i_uid = sbi->uid;
      }

      jfs_ip->saved_gid = le32_to_cpu(dip->di_gid);
      if (sbi->gid == -1)
            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 (sbi->uid == -1)
            dip->di_uid = cpu_to_le32(ip->i_uid);
      else
            dip->di_uid = cpu_to_le32(jfs_ip->saved_uid);
      if (sbi->gid == -1)
            dip->di_gid = cpu_to_le32(ip->i_gid);
      else
            dip->di_gid = cpu_to_le32(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);
}

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