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jfs_txnmgr.c

/*
 *   Copyright (C) International Business Machines Corp., 2000-2005
 *   Portions Copyright (C) Christoph Hellwig, 2001-2002
 *
 *   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_txnmgr.c: transaction manager
 *
 * notes:
 * transaction starts with txBegin() and ends with txCommit()
 * or txAbort().
 *
 * tlock is acquired at the time of update;
 * (obviate scan at commit time for xtree and dtree)
 * tlock and mp points to each other;
 * (no hashlist for mp -> tlock).
 *
 * special cases:
 * tlock on in-memory inode:
 * in-place tlock in the in-memory inode itself;
 * converted to page lock by iWrite() at commit time.
 *
 * tlock during write()/mmap() under anonymous transaction (tid = 0):
 * transferred (?) to transaction at commit time.
 *
 * use the page itself to update allocation maps
 * (obviate intermediate replication of allocation/deallocation data)
 * hold on to mp+lock thru update of maps
 */

#include <linux/fs.h>
#include <linux/vmalloc.h>
#include <linux/smp_lock.h>
#include <linux/completion.h>
#include <linux/suspend.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kthread.h>
#include "jfs_incore.h"
#include "jfs_inode.h"
#include "jfs_filsys.h"
#include "jfs_metapage.h"
#include "jfs_dinode.h"
#include "jfs_imap.h"
#include "jfs_dmap.h"
#include "jfs_superblock.h"
#include "jfs_debug.h"

/*
 *      transaction management structures
 */
static struct {
      int freetid;            /* index of a free tid structure */
      int freelock;           /* index first free lock word */
      wait_queue_head_t freewait;   /* eventlist of free tblock */
      wait_queue_head_t freelockwait;     /* eventlist of free tlock */
      wait_queue_head_t lowlockwait;      /* eventlist of ample tlocks */
      int tlocksInUse;  /* Number of tlocks in use */
      spinlock_t LazyLock;    /* synchronize sync_queue & unlock_queue */
/*    struct tblock *sync_queue; * Transactions waiting for data sync */
      struct list_head unlock_queue;      /* Txns waiting to be released */
      struct list_head anon_list;   /* inodes having anonymous txns */
      struct list_head anon_list2;  /* inodes having anonymous txns
                                 that couldn't be sync'ed */
} TxAnchor;

int jfs_tlocks_low;           /* Indicates low number of available tlocks */

#ifdef CONFIG_JFS_STATISTICS
static struct {
      uint txBegin;
      uint txBegin_barrier;
      uint txBegin_lockslow;
      uint txBegin_freetid;
      uint txBeginAnon;
      uint txBeginAnon_barrier;
      uint txBeginAnon_lockslow;
      uint txLockAlloc;
      uint txLockAlloc_freelock;
} TxStat;
#endif

static int nTxBlock = -1;     /* number of transaction blocks */
module_param(nTxBlock, int, 0);
MODULE_PARM_DESC(nTxBlock,
             "Number of transaction blocks (max:65536)");

static int nTxLock = -1;      /* number of transaction locks */
module_param(nTxLock, int, 0);
MODULE_PARM_DESC(nTxLock,
             "Number of transaction locks (max:65536)");

struct tblock *TxBlock;         /* transaction block table */
static int TxLockLWM;         /* Low water mark for number of txLocks used */
static int TxLockHWM;         /* High water mark for number of txLocks used */
static int TxLockVHWM;        /* Very High water mark */
struct tlock *TxLock;           /* transaction lock table */

/*
 *      transaction management lock
 */
static DEFINE_SPINLOCK(jfsTxnLock);

#define TXN_LOCK()              spin_lock(&jfsTxnLock)
#define TXN_UNLOCK()            spin_unlock(&jfsTxnLock)

#define LAZY_LOCK_INIT()      spin_lock_init(&TxAnchor.LazyLock);
#define LAZY_LOCK(flags)      spin_lock_irqsave(&TxAnchor.LazyLock, flags)
#define LAZY_UNLOCK(flags) spin_unlock_irqrestore(&TxAnchor.LazyLock, flags)

static DECLARE_WAIT_QUEUE_HEAD(jfs_commit_thread_wait);
static int jfs_commit_thread_waking;

/*
 * Retry logic exist outside these macros to protect from spurrious wakeups.
 */
static inline void TXN_SLEEP_DROP_LOCK(wait_queue_head_t * event)
{
      DECLARE_WAITQUEUE(wait, current);

      add_wait_queue(event, &wait);
      set_current_state(TASK_UNINTERRUPTIBLE);
      TXN_UNLOCK();
      schedule();
      current->state = TASK_RUNNING;
      remove_wait_queue(event, &wait);
}

#define TXN_SLEEP(event)\
{\
      TXN_SLEEP_DROP_LOCK(event);\
      TXN_LOCK();\
}

#define TXN_WAKEUP(event) wake_up_all(event)

/*
 *      statistics
 */
static struct {
      tid_t maxtid;           /* 4: biggest tid ever used */
      lid_t maxlid;           /* 4: biggest lid ever used */
      int ntid;         /* 4: # of transactions performed */
      int nlid;         /* 4: # of tlocks acquired */
      int waitlock;           /* 4: # of tlock wait */
} stattx;

/*
 * forward references
 */
static int diLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
            struct tlock * tlck, struct commit * cd);
static int dataLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
            struct tlock * tlck);
static void dtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
            struct tlock * tlck);
static void mapLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
            struct tlock * tlck);
static void txAllocPMap(struct inode *ip, struct maplock * maplock,
            struct tblock * tblk);
static void txForce(struct tblock * tblk);
static int txLog(struct jfs_log * log, struct tblock * tblk,
            struct commit * cd);
static void txUpdateMap(struct tblock * tblk);
static void txRelease(struct tblock * tblk);
static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
         struct tlock * tlck);
static void LogSyncRelease(struct metapage * mp);

/*
 *              transaction block/lock management
 *              ---------------------------------
 */

/*
 * Get a transaction lock from the free list.  If the number in use is
 * greater than the high water mark, wake up the sync daemon.  This should
 * free some anonymous transaction locks.  (TXN_LOCK must be held.)
 */
static lid_t txLockAlloc(void)
{
      lid_t lid;

      INCREMENT(TxStat.txLockAlloc);
      if (!TxAnchor.freelock) {
            INCREMENT(TxStat.txLockAlloc_freelock);
      }

      while (!(lid = TxAnchor.freelock))
            TXN_SLEEP(&TxAnchor.freelockwait);
      TxAnchor.freelock = TxLock[lid].next;
      HIGHWATERMARK(stattx.maxlid, lid);
      if ((++TxAnchor.tlocksInUse > TxLockHWM) && (jfs_tlocks_low == 0)) {
            jfs_info("txLockAlloc tlocks low");
            jfs_tlocks_low = 1;
            wake_up_process(jfsSyncThread);
      }

      return lid;
}

static void txLockFree(lid_t lid)
{
      TxLock[lid].tid = 0;
      TxLock[lid].next = TxAnchor.freelock;
      TxAnchor.freelock = lid;
      TxAnchor.tlocksInUse--;
      if (jfs_tlocks_low && (TxAnchor.tlocksInUse < TxLockLWM)) {
            jfs_info("txLockFree jfs_tlocks_low no more");
            jfs_tlocks_low = 0;
            TXN_WAKEUP(&TxAnchor.lowlockwait);
      }
      TXN_WAKEUP(&TxAnchor.freelockwait);
}

/*
 * NAME:        txInit()
 *
 * FUNCTION:    initialize transaction management structures
 *
 * RETURN:
 *
 * serialization: single thread at jfs_init()
 */
int txInit(void)
{
      int k, size;
      struct sysinfo si;

      /* Set defaults for nTxLock and nTxBlock if unset */

      if (nTxLock == -1) {
            if (nTxBlock == -1) {
                  /* Base default on memory size */
                  si_meminfo(&si);
                  if (si.totalram > (256 * 1024)) /* 1 GB */
                        nTxLock = 64 * 1024;
                  else
                        nTxLock = si.totalram >> 2;
            } else if (nTxBlock > (8 * 1024))
                  nTxLock = 64 * 1024;
            else
                  nTxLock = nTxBlock << 3;
      }
      if (nTxBlock == -1)
            nTxBlock = nTxLock >> 3;

      /* Verify tunable parameters */
      if (nTxBlock < 16)
            nTxBlock = 16;    /* No one should set it this low */
      if (nTxBlock > 65536)
            nTxBlock = 65536;
      if (nTxLock < 256)
            nTxLock = 256;    /* No one should set it this low */
      if (nTxLock > 65536)
            nTxLock = 65536;

      printk(KERN_INFO "JFS: nTxBlock = %d, nTxLock = %d\n",
             nTxBlock, nTxLock);
      /*
       * initialize transaction block (tblock) table
       *
       * transaction id (tid) = tblock index
       * tid = 0 is reserved.
       */
      TxLockLWM = (nTxLock * 4) / 10;
      TxLockHWM = (nTxLock * 7) / 10;
      TxLockVHWM = (nTxLock * 8) / 10;

      size = sizeof(struct tblock) * nTxBlock;
      TxBlock = (struct tblock *) vmalloc(size);
      if (TxBlock == NULL)
            return -ENOMEM;

      for (k = 1; k < nTxBlock - 1; k++) {
            TxBlock[k].next = k + 1;
            init_waitqueue_head(&TxBlock[k].gcwait);
            init_waitqueue_head(&TxBlock[k].waitor);
      }
      TxBlock[k].next = 0;
      init_waitqueue_head(&TxBlock[k].gcwait);
      init_waitqueue_head(&TxBlock[k].waitor);

      TxAnchor.freetid = 1;
      init_waitqueue_head(&TxAnchor.freewait);

      stattx.maxtid = 1;      /* statistics */

      /*
       * initialize transaction lock (tlock) table
       *
       * transaction lock id = tlock index
       * tlock id = 0 is reserved.
       */
      size = sizeof(struct tlock) * nTxLock;
      TxLock = (struct tlock *) vmalloc(size);
      if (TxLock == NULL) {
            vfree(TxBlock);
            return -ENOMEM;
      }

      /* initialize tlock table */
      for (k = 1; k < nTxLock - 1; k++)
            TxLock[k].next = k + 1;
      TxLock[k].next = 0;
      init_waitqueue_head(&TxAnchor.freelockwait);
      init_waitqueue_head(&TxAnchor.lowlockwait);

      TxAnchor.freelock = 1;
      TxAnchor.tlocksInUse = 0;
      INIT_LIST_HEAD(&TxAnchor.anon_list);
      INIT_LIST_HEAD(&TxAnchor.anon_list2);

      LAZY_LOCK_INIT();
      INIT_LIST_HEAD(&TxAnchor.unlock_queue);

      stattx.maxlid = 1;      /* statistics */

      return 0;
}

/*
 * NAME:        txExit()
 *
 * FUNCTION:    clean up when module is unloaded
 */
void txExit(void)
{
      vfree(TxLock);
      TxLock = NULL;
      vfree(TxBlock);
      TxBlock = NULL;
}

/*
 * NAME:        txBegin()
 *
 * FUNCTION:    start a transaction.
 *
 * PARAMETER:   sb      - superblock
 *              flag    - force for nested tx;
 *
 * RETURN:  tid   - transaction id
 *
 * note: flag force allows to start tx for nested tx
 * to prevent deadlock on logsync barrier;
 */
tid_t txBegin(struct super_block *sb, int flag)
{
      tid_t t;
      struct tblock *tblk;
      struct jfs_log *log;

      jfs_info("txBegin: flag = 0x%x", flag);
      log = JFS_SBI(sb)->log;

      TXN_LOCK();

      INCREMENT(TxStat.txBegin);

      retry:
      if (!(flag & COMMIT_FORCE)) {
            /*
             * synchronize with logsync barrier
             */
            if (test_bit(log_SYNCBARRIER, &log->flag) ||
                test_bit(log_QUIESCE, &log->flag)) {
                  INCREMENT(TxStat.txBegin_barrier);
                  TXN_SLEEP(&log->syncwait);
                  goto retry;
            }
      }
      if (flag == 0) {
            /*
             * Don't begin transaction if we're getting starved for tlocks
             * unless COMMIT_FORCE or COMMIT_INODE (which may ultimately
             * free tlocks)
             */
            if (TxAnchor.tlocksInUse > TxLockVHWM) {
                  INCREMENT(TxStat.txBegin_lockslow);
                  TXN_SLEEP(&TxAnchor.lowlockwait);
                  goto retry;
            }
      }

      /*
       * allocate transaction id/block
       */
      if ((t = TxAnchor.freetid) == 0) {
            jfs_info("txBegin: waiting for free tid");
            INCREMENT(TxStat.txBegin_freetid);
            TXN_SLEEP(&TxAnchor.freewait);
            goto retry;
      }

      tblk = tid_to_tblock(t);

      if ((tblk->next == 0) && !(flag & COMMIT_FORCE)) {
            /* Don't let a non-forced transaction take the last tblk */
            jfs_info("txBegin: waiting for free tid");
            INCREMENT(TxStat.txBegin_freetid);
            TXN_SLEEP(&TxAnchor.freewait);
            goto retry;
      }

      TxAnchor.freetid = tblk->next;

      /*
       * initialize transaction
       */

      /*
       * We can't zero the whole thing or we screw up another thread being
       * awakened after sleeping on tblk->waitor
       *
       * memset(tblk, 0, sizeof(struct tblock));
       */
      tblk->next = tblk->last = tblk->xflag = tblk->flag = tblk->lsn = 0;

      tblk->sb = sb;
      ++log->logtid;
      tblk->logtid = log->logtid;

      ++log->active;

      HIGHWATERMARK(stattx.maxtid, t);    /* statistics */
      INCREMENT(stattx.ntid); /* statistics */

      TXN_UNLOCK();

      jfs_info("txBegin: returning tid = %d", t);

      return t;
}

/*
 * NAME:        txBeginAnon()
 *
 * FUNCTION:    start an anonymous transaction.
 *          Blocks if logsync or available tlocks are low to prevent
 *          anonymous tlocks from depleting supply.
 *
 * PARAMETER:   sb      - superblock
 *
 * RETURN:  none
 */
void txBeginAnon(struct super_block *sb)
{
      struct jfs_log *log;

      log = JFS_SBI(sb)->log;

      TXN_LOCK();
      INCREMENT(TxStat.txBeginAnon);

      retry:
      /*
       * synchronize with logsync barrier
       */
      if (test_bit(log_SYNCBARRIER, &log->flag) ||
          test_bit(log_QUIESCE, &log->flag)) {
            INCREMENT(TxStat.txBeginAnon_barrier);
            TXN_SLEEP(&log->syncwait);
            goto retry;
      }

      /*
       * Don't begin transaction if we're getting starved for tlocks
       */
      if (TxAnchor.tlocksInUse > TxLockVHWM) {
            INCREMENT(TxStat.txBeginAnon_lockslow);
            TXN_SLEEP(&TxAnchor.lowlockwait);
            goto retry;
      }
      TXN_UNLOCK();
}

/*
 *      txEnd()
 *
 * function: free specified transaction block.
 *
 *      logsync barrier processing:
 *
 * serialization:
 */
void txEnd(tid_t tid)
{
      struct tblock *tblk = tid_to_tblock(tid);
      struct jfs_log *log;

      jfs_info("txEnd: tid = %d", tid);
      TXN_LOCK();

      /*
       * wakeup transactions waiting on the page locked
       * by the current transaction
       */
      TXN_WAKEUP(&tblk->waitor);

      log = JFS_SBI(tblk->sb)->log;

      /*
       * Lazy commit thread can't free this guy until we mark it UNLOCKED,
       * otherwise, we would be left with a transaction that may have been
       * reused.
       *
       * Lazy commit thread will turn off tblkGC_LAZY before calling this
       * routine.
       */
      if (tblk->flag & tblkGC_LAZY) {
            jfs_info("txEnd called w/lazy tid: %d, tblk = 0x%p", tid, tblk);
            TXN_UNLOCK();

            spin_lock_irq(&log->gclock);  // LOGGC_LOCK
            tblk->flag |= tblkGC_UNLOCKED;
            spin_unlock_irq(&log->gclock);      // LOGGC_UNLOCK
            return;
      }

      jfs_info("txEnd: tid: %d, tblk = 0x%p", tid, tblk);

      assert(tblk->next == 0);

      /*
       * insert tblock back on freelist
       */
      tblk->next = TxAnchor.freetid;
      TxAnchor.freetid = tid;

      /*
       * mark the tblock not active
       */
      if (--log->active == 0) {
            clear_bit(log_FLUSH, &log->flag);

            /*
             * synchronize with logsync barrier
             */
            if (test_bit(log_SYNCBARRIER, &log->flag)) {
                  TXN_UNLOCK();

                  /* write dirty metadata & forward log syncpt */
                  jfs_syncpt(log, 1);

                  jfs_info("log barrier off: 0x%x", log->lsn);

                  /* enable new transactions start */
                  clear_bit(log_SYNCBARRIER, &log->flag);

                  /* wakeup all waitors for logsync barrier */
                  TXN_WAKEUP(&log->syncwait);

                  goto wakeup;
            }
      }

      TXN_UNLOCK();
wakeup:
      /*
       * wakeup all waitors for a free tblock
       */
      TXN_WAKEUP(&TxAnchor.freewait);
}

/*
 *      txLock()
 *
 * function: acquire a transaction lock on the specified <mp>
 *
 * parameter:
 *
 * return:      transaction lock id
 *
 * serialization:
 */
struct tlock *txLock(tid_t tid, struct inode *ip, struct metapage * mp,
                 int type)
{
      struct jfs_inode_info *jfs_ip = JFS_IP(ip);
      int dir_xtree = 0;
      lid_t lid;
      tid_t xtid;
      struct tlock *tlck;
      struct xtlock *xtlck;
      struct linelock *linelock;
      xtpage_t *p;
      struct tblock *tblk;

      TXN_LOCK();

      if (S_ISDIR(ip->i_mode) && (type & tlckXTREE) &&
          !(mp->xflag & COMMIT_PAGE)) {
            /*
             * Directory inode is special.  It can have both an xtree tlock
             * and a dtree tlock associated with it.
             */
            dir_xtree = 1;
            lid = jfs_ip->xtlid;
      } else
            lid = mp->lid;

      /* is page not locked by a transaction ? */
      if (lid == 0)
            goto allocateLock;

      jfs_info("txLock: tid:%d ip:0x%p mp:0x%p lid:%d", tid, ip, mp, lid);

      /* is page locked by the requester transaction ? */
      tlck = lid_to_tlock(lid);
      if ((xtid = tlck->tid) == tid) {
            TXN_UNLOCK();
            goto grantLock;
      }

      /*
       * is page locked by anonymous transaction/lock ?
       *
       * (page update without transaction (i.e., file write) is
       * locked under anonymous transaction tid = 0:
       * anonymous tlocks maintained on anonymous tlock list of
       * the inode of the page and available to all anonymous
       * transactions until txCommit() time at which point
       * they are transferred to the transaction tlock list of
       * the commiting transaction of the inode)
       */
      if (xtid == 0) {
            tlck->tid = tid;
            TXN_UNLOCK();
            tblk = tid_to_tblock(tid);
            /*
             * The order of the tlocks in the transaction is important
             * (during truncate, child xtree pages must be freed before
             * parent's tlocks change the working map).
             * Take tlock off anonymous list and add to tail of
             * transaction list
             *
             * Note:  We really need to get rid of the tid & lid and
             * use list_head's.  This code is getting UGLY!
             */
            if (jfs_ip->atlhead == lid) {
                  if (jfs_ip->atltail == lid) {
                        /* only anonymous txn.
                         * Remove from anon_list
                         */
                        TXN_LOCK();
                        list_del_init(&jfs_ip->anon_inode_list);
                        TXN_UNLOCK();
                  }
                  jfs_ip->atlhead = tlck->next;
            } else {
                  lid_t last;
                  for (last = jfs_ip->atlhead;
                       lid_to_tlock(last)->next != lid;
                       last = lid_to_tlock(last)->next) {
                        assert(last);
                  }
                  lid_to_tlock(last)->next = tlck->next;
                  if (jfs_ip->atltail == lid)
                        jfs_ip->atltail = last;
            }

            /* insert the tlock at tail of transaction tlock list */

            if (tblk->next)
                  lid_to_tlock(tblk->last)->next = lid;
            else
                  tblk->next = lid;
            tlck->next = 0;
            tblk->last = lid;

            goto grantLock;
      }

      goto waitLock;

      /*
       * allocate a tlock
       */
      allocateLock:
      lid = txLockAlloc();
      tlck = lid_to_tlock(lid);

      /*
       * initialize tlock
       */
      tlck->tid = tid;

      TXN_UNLOCK();

      /* mark tlock for meta-data page */
      if (mp->xflag & COMMIT_PAGE) {

            tlck->flag = tlckPAGELOCK;

            /* mark the page dirty and nohomeok */
            metapage_nohomeok(mp);

            jfs_info("locking mp = 0x%p, nohomeok = %d tid = %d tlck = 0x%p",
                   mp, mp->nohomeok, tid, tlck);

            /* if anonymous transaction, and buffer is on the group
             * commit synclist, mark inode to show this.  This will
             * prevent the buffer from being marked nohomeok for too
             * long a time.
             */
            if ((tid == 0) && mp->lsn)
                  set_cflag(COMMIT_Synclist, ip);
      }
      /* mark tlock for in-memory inode */
      else
            tlck->flag = tlckINODELOCK;

      if (S_ISDIR(ip->i_mode))
            tlck->flag |= tlckDIRECTORY;

      tlck->type = 0;

      /* bind the tlock and the page */
      tlck->ip = ip;
      tlck->mp = mp;
      if (dir_xtree)
            jfs_ip->xtlid = lid;
      else
            mp->lid = lid;

      /*
       * enqueue transaction lock to transaction/inode
       */
      /* insert the tlock at tail of transaction tlock list */
      if (tid) {
            tblk = tid_to_tblock(tid);
            if (tblk->next)
                  lid_to_tlock(tblk->last)->next = lid;
            else
                  tblk->next = lid;
            tlck->next = 0;
            tblk->last = lid;
      }
      /* anonymous transaction:
       * insert the tlock at head of inode anonymous tlock list
       */
      else {
            tlck->next = jfs_ip->atlhead;
            jfs_ip->atlhead = lid;
            if (tlck->next == 0) {
                  /* This inode's first anonymous transaction */
                  jfs_ip->atltail = lid;
                  TXN_LOCK();
                  list_add_tail(&jfs_ip->anon_inode_list,
                              &TxAnchor.anon_list);
                  TXN_UNLOCK();
            }
      }

      /* initialize type dependent area for linelock */
      linelock = (struct linelock *) & tlck->lock;
      linelock->next = 0;
      linelock->flag = tlckLINELOCK;
      linelock->maxcnt = TLOCKSHORT;
      linelock->index = 0;

      switch (type & tlckTYPE) {
      case tlckDTREE:
            linelock->l2linesize = L2DTSLOTSIZE;
            break;

      case tlckXTREE:
            linelock->l2linesize = L2XTSLOTSIZE;

            xtlck = (struct xtlock *) linelock;
            xtlck->header.offset = 0;
            xtlck->header.length = 2;

            if (type & tlckNEW) {
                  xtlck->lwm.offset = XTENTRYSTART;
            } else {
                  if (mp->xflag & COMMIT_PAGE)
                        p = (xtpage_t *) mp->data;
                  else
                        p = &jfs_ip->i_xtroot;
                  xtlck->lwm.offset =
                      le16_to_cpu(p->header.nextindex);
            }
            xtlck->lwm.length = 0;  /* ! */
            xtlck->twm.offset = 0;
            xtlck->hwm.offset = 0;

            xtlck->index = 2;
            break;

      case tlckINODE:
            linelock->l2linesize = L2INODESLOTSIZE;
            break;

      case tlckDATA:
            linelock->l2linesize = L2DATASLOTSIZE;
            break;

      default:
            jfs_err("UFO tlock:0x%p", tlck);
      }

      /*
       * update tlock vector
       */
      grantLock:
      tlck->type |= type;

      return tlck;

      /*
       * page is being locked by another transaction:
       */
      waitLock:
      /* Only locks on ipimap or ipaimap should reach here */
      /* assert(jfs_ip->fileset == AGGREGATE_I); */
      if (jfs_ip->fileset != AGGREGATE_I) {
            jfs_err("txLock: trying to lock locked page!");
            dump_mem("ip", ip, sizeof(struct inode));
            dump_mem("mp", mp, sizeof(struct metapage));
            dump_mem("Locker's tblk", tid_to_tblock(tid),
                   sizeof(struct tblock));
            dump_mem("Tlock", tlck, sizeof(struct tlock));
            BUG();
      }
      INCREMENT(stattx.waitlock);   /* statistics */
      TXN_UNLOCK();
      release_metapage(mp);
      TXN_LOCK();
      xtid = tlck->tid; /* reacquire after dropping TXN_LOCK */

      jfs_info("txLock: in waitLock, tid = %d, xtid = %d, lid = %d",
             tid, xtid, lid);

      /* Recheck everything since dropping TXN_LOCK */
      if (xtid && (tlck->mp == mp) && (mp->lid == lid))
            TXN_SLEEP_DROP_LOCK(&tid_to_tblock(xtid)->waitor);
      else
            TXN_UNLOCK();
      jfs_info("txLock: awakened     tid = %d, lid = %d", tid, lid);

      return NULL;
}

/*
 * NAME:        txRelease()
 *
 * FUNCTION:    Release buffers associated with transaction locks, but don't
 *          mark homeok yet.  The allows other transactions to modify
 *          buffers, but won't let them go to disk until commit record
 *          actually gets written.
 *
 * PARAMETER:
 *              tblk    -
 *
 * RETURN:      Errors from subroutines.
 */
static void txRelease(struct tblock * tblk)
{
      struct metapage *mp;
      lid_t lid;
      struct tlock *tlck;

      TXN_LOCK();

      for (lid = tblk->next; lid; lid = tlck->next) {
            tlck = lid_to_tlock(lid);
            if ((mp = tlck->mp) != NULL &&
                (tlck->type & tlckBTROOT) == 0) {
                  assert(mp->xflag & COMMIT_PAGE);
                  mp->lid = 0;
            }
      }

      /*
       * wakeup transactions waiting on a page locked
       * by the current transaction
       */
      TXN_WAKEUP(&tblk->waitor);

      TXN_UNLOCK();
}

/*
 * NAME:        txUnlock()
 *
 * FUNCTION:    Initiates pageout of pages modified by tid in journalled
 *              objects and frees their lockwords.
 */
static void txUnlock(struct tblock * tblk)
{
      struct tlock *tlck;
      struct linelock *linelock;
      lid_t lid, next, llid, k;
      struct metapage *mp;
      struct jfs_log *log;
      int difft, diffp;
      unsigned long flags;

      jfs_info("txUnlock: tblk = 0x%p", tblk);
      log = JFS_SBI(tblk->sb)->log;

      /*
       * mark page under tlock homeok (its log has been written):
       */
      for (lid = tblk->next; lid; lid = next) {
            tlck = lid_to_tlock(lid);
            next = tlck->next;

            jfs_info("unlocking lid = %d, tlck = 0x%p", lid, tlck);

            /* unbind page from tlock */
            if ((mp = tlck->mp) != NULL &&
                (tlck->type & tlckBTROOT) == 0) {
                  assert(mp->xflag & COMMIT_PAGE);

                  /* hold buffer
                   */
                  hold_metapage(mp);

                  assert(mp->nohomeok > 0);
                  _metapage_homeok(mp);

                  /* inherit younger/larger clsn */
                  LOGSYNC_LOCK(log, flags);
                  if (mp->clsn) {
                        logdiff(difft, tblk->clsn, log);
                        logdiff(diffp, mp->clsn, log);
                        if (difft > diffp)
                              mp->clsn = tblk->clsn;
                  } else
                        mp->clsn = tblk->clsn;
                  LOGSYNC_UNLOCK(log, flags);

                  assert(!(tlck->flag & tlckFREEPAGE));

                  put_metapage(mp);
            }

            /* insert tlock, and linelock(s) of the tlock if any,
             * at head of freelist
             */
            TXN_LOCK();

            llid = ((struct linelock *) & tlck->lock)->next;
            while (llid) {
                  linelock = (struct linelock *) lid_to_tlock(llid);
                  k = linelock->next;
                  txLockFree(llid);
                  llid = k;
            }
            txLockFree(lid);

            TXN_UNLOCK();
      }
      tblk->next = tblk->last = 0;

      /*
       * remove tblock from logsynclist
       * (allocation map pages inherited lsn of tblk and
       * has been inserted in logsync list at txUpdateMap())
       */
      if (tblk->lsn) {
            LOGSYNC_LOCK(log, flags);
            log->count--;
            list_del(&tblk->synclist);
            LOGSYNC_UNLOCK(log, flags);
      }
}

/*
 *      txMaplock()
 *
 * function: allocate a transaction lock for freed page/entry;
 *      for freed page, maplock is used as xtlock/dtlock type;
 */
struct tlock *txMaplock(tid_t tid, struct inode *ip, int type)
{
      struct jfs_inode_info *jfs_ip = JFS_IP(ip);
      lid_t lid;
      struct tblock *tblk;
      struct tlock *tlck;
      struct maplock *maplock;

      TXN_LOCK();

      /*
       * allocate a tlock
       */
      lid = txLockAlloc();
      tlck = lid_to_tlock(lid);

      /*
       * initialize tlock
       */
      tlck->tid = tid;

      /* bind the tlock and the object */
      tlck->flag = tlckINODELOCK;
      if (S_ISDIR(ip->i_mode))
            tlck->flag |= tlckDIRECTORY;
      tlck->ip = ip;
      tlck->mp = NULL;

      tlck->type = type;

      /*
       * enqueue transaction lock to transaction/inode
       */
      /* insert the tlock at tail of transaction tlock list */
      if (tid) {
            tblk = tid_to_tblock(tid);
            if (tblk->next)
                  lid_to_tlock(tblk->last)->next = lid;
            else
                  tblk->next = lid;
            tlck->next = 0;
            tblk->last = lid;
      }
      /* anonymous transaction:
       * insert the tlock at head of inode anonymous tlock list
       */
      else {
            tlck->next = jfs_ip->atlhead;
            jfs_ip->atlhead = lid;
            if (tlck->next == 0) {
                  /* This inode's first anonymous transaction */
                  jfs_ip->atltail = lid;
                  list_add_tail(&jfs_ip->anon_inode_list,
                              &TxAnchor.anon_list);
            }
      }

      TXN_UNLOCK();

      /* initialize type dependent area for maplock */
      maplock = (struct maplock *) & tlck->lock;
      maplock->next = 0;
      maplock->maxcnt = 0;
      maplock->index = 0;

      return tlck;
}

/*
 *      txLinelock()
 *
 * function: allocate a transaction lock for log vector list
 */
struct linelock *txLinelock(struct linelock * tlock)
{
      lid_t lid;
      struct tlock *tlck;
      struct linelock *linelock;

      TXN_LOCK();

      /* allocate a TxLock structure */
      lid = txLockAlloc();
      tlck = lid_to_tlock(lid);

      TXN_UNLOCK();

      /* initialize linelock */
      linelock = (struct linelock *) tlck;
      linelock->next = 0;
      linelock->flag = tlckLINELOCK;
      linelock->maxcnt = TLOCKLONG;
      linelock->index = 0;
      if (tlck->flag & tlckDIRECTORY)
            linelock->flag |= tlckDIRECTORY;

      /* append linelock after tlock */
      linelock->next = tlock->next;
      tlock->next = lid;

      return linelock;
}

/*
 *              transaction commit management
 *              -----------------------------
 */

/*
 * NAME:        txCommit()
 *
 * FUNCTION:    commit the changes to the objects specified in
 *              clist.  For journalled segments only the
 *              changes of the caller are committed, ie by tid.
 *              for non-journalled segments the data are flushed to
 *              disk and then the change to the disk inode and indirect
 *              blocks committed (so blocks newly allocated to the
 *              segment will be made a part of the segment atomically).
 *
 *              all of the segments specified in clist must be in
 *              one file system. no more than 6 segments are needed
 *              to handle all unix svcs.
 *
 *              if the i_nlink field (i.e. disk inode link count)
 *              is zero, and the type of inode is a regular file or
 *              directory, or symbolic link , the inode is truncated
 *              to zero length. the truncation is committed but the
 *              VM resources are unaffected until it is closed (see
 *              iput and iclose).
 *
 * PARAMETER:
 *
 * RETURN:
 *
 * serialization:
 *              on entry the inode lock on each segment is assumed
 *              to be held.
 *
 * i/o error:
 */
int txCommit(tid_t tid,       /* transaction identifier */
           int nip,           /* number of inodes to commit */
           struct inode **iplist,   /* list of inode to commit */
           int flag)
{
      int rc = 0;
      struct commit cd;
      struct jfs_log *log;
      struct tblock *tblk;
      struct lrd *lrd;
      int lsn;
      struct inode *ip;
      struct jfs_inode_info *jfs_ip;
      int k, n;
      ino_t top;
      struct super_block *sb;

      jfs_info("txCommit, tid = %d, flag = %d", tid, flag);
      /* is read-only file system ? */
      if (isReadOnly(iplist[0])) {
            rc = -EROFS;
            goto TheEnd;
      }

      sb = cd.sb = iplist[0]->i_sb;
      cd.tid = tid;

      if (tid == 0)
            tid = txBegin(sb, 0);
      tblk = tid_to_tblock(tid);

      /*
       * initialize commit structure
       */
      log = JFS_SBI(sb)->log;
      cd.log = log;

      /* initialize log record descriptor in commit */
      lrd = &cd.lrd;
      lrd->logtid = cpu_to_le32(tblk->logtid);
      lrd->backchain = 0;

      tblk->xflag |= flag;

      if ((flag & (COMMIT_FORCE | COMMIT_SYNC)) == 0)
            tblk->xflag |= COMMIT_LAZY;
      /*
       *      prepare non-journaled objects for commit
       *
       * flush data pages of non-journaled file
       * to prevent the file getting non-initialized disk blocks
       * in case of crash.
       * (new blocks - )
       */
      cd.iplist = iplist;
      cd.nip = nip;

      /*
       *      acquire transaction lock on (on-disk) inodes
       *
       * update on-disk inode from in-memory inode
       * acquiring transaction locks for AFTER records
       * on the on-disk inode of file object
       *
       * sort the inodes array by inode number in descending order
       * to prevent deadlock when acquiring transaction lock
       * of on-disk inodes on multiple on-disk inode pages by
       * multiple concurrent transactions
       */
      for (k = 0; k < cd.nip; k++) {
            top = (cd.iplist[k])->i_ino;
            for (n = k + 1; n < cd.nip; n++) {
                  ip = cd.iplist[n];
                  if (ip->i_ino > top) {
                        top = ip->i_ino;
                        cd.iplist[n] = cd.iplist[k];
                        cd.iplist[k] = ip;
                  }
            }

            ip = cd.iplist[k];
            jfs_ip = JFS_IP(ip);

            /*
             * BUGBUG - This code has temporarily been removed.  The
             * intent is to ensure that any file data is written before
             * the metadata is committed to the journal.  This prevents
             * uninitialized data from appearing in a file after the
             * journal has been replayed.  (The uninitialized data
             * could be sensitive data removed by another user.)
             *
             * The problem now is that we are holding the IWRITELOCK
             * on the inode, and calling filemap_fdatawrite on an
             * unmapped page will cause a deadlock in jfs_get_block.
             *
             * The long term solution is to pare down the use of
             * IWRITELOCK.  We are currently holding it too long.
             * We could also be smarter about which data pages need
             * to be written before the transaction is committed and
             * when we don't need to worry about it at all.
             *
             * if ((!S_ISDIR(ip->i_mode))
             *    && (tblk->flag & COMMIT_DELETE) == 0)
             *    filemap_write_and_wait(ip->i_mapping);
             */

            /*
             * Mark inode as not dirty.  It will still be on the dirty
             * inode list, but we'll know not to commit it again unless
             * it gets marked dirty again
             */
            clear_cflag(COMMIT_Dirty, ip);

            /* inherit anonymous tlock(s) of inode */
            if (jfs_ip->atlhead) {
                  lid_to_tlock(jfs_ip->atltail)->next = tblk->next;
                  tblk->next = jfs_ip->atlhead;
                  if (!tblk->last)
                        tblk->last = jfs_ip->atltail;
                  jfs_ip->atlhead = jfs_ip->atltail = 0;
                  TXN_LOCK();
                  list_del_init(&jfs_ip->anon_inode_list);
                  TXN_UNLOCK();
            }

            /*
             * acquire transaction lock on on-disk inode page
             * (become first tlock of the tblk's tlock list)
             */
            if (((rc = diWrite(tid, ip))))
                  goto out;
      }

      /*
       *      write log records from transaction locks
       *
       * txUpdateMap() resets XAD_NEW in XAD.
       */
      if ((rc = txLog(log, tblk, &cd)))
            goto TheEnd;

      /*
       * Ensure that inode isn't reused before
       * lazy commit thread finishes processing
       */
      if (tblk->xflag & COMMIT_DELETE) {
            atomic_inc(&tblk->u.ip->i_count);
            /*
             * Avoid a rare deadlock
             *
             * If the inode is locked, we may be blocked in
             * jfs_commit_inode.  If so, we don't want the
             * lazy_commit thread doing the last iput() on the inode
             * since that may block on the locked inode.  Instead,
             * commit the transaction synchronously, so the last iput
             * will be done by the calling thread (or later)
             */
            if (tblk->u.ip->i_state & I_LOCK)
                  tblk->xflag &= ~COMMIT_LAZY;
      }

      ASSERT((!(tblk->xflag & COMMIT_DELETE)) ||
             ((tblk->u.ip->i_nlink == 0) &&
            !test_cflag(COMMIT_Nolink, tblk->u.ip)));

      /*
       *      write COMMIT log record
       */
      lrd->type = cpu_to_le16(LOG_COMMIT);
      lrd->length = 0;
      lsn = lmLog(log, tblk, lrd, NULL);

      lmGroupCommit(log, tblk);

      /*
       *      - transaction is now committed -
       */

      /*
       * force pages in careful update
       * (imap addressing structure update)
       */
      if (flag & COMMIT_FORCE)
            txForce(tblk);

      /*
       *      update allocation map.
       *
       * update inode allocation map and inode:
       * free pager lock on memory object of inode if any.
       * update  block allocation map.
       *
       * txUpdateMap() resets XAD_NEW in XAD.
       */
      if (tblk->xflag & COMMIT_FORCE)
            txUpdateMap(tblk);

      /*
       *      free transaction locks and pageout/free pages
       */
      txRelease(tblk);

      if ((tblk->flag & tblkGC_LAZY) == 0)
            txUnlock(tblk);


      /*
       *      reset in-memory object state
       */
      for (k = 0; k < cd.nip; k++) {
            ip = cd.iplist[k];
            jfs_ip = JFS_IP(ip);

            /*
             * reset in-memory inode state
             */
            jfs_ip->bxflag = 0;
            jfs_ip->blid = 0;
      }

      out:
      if (rc != 0)
            txAbort(tid, 1);

      TheEnd:
      jfs_info("txCommit: tid = %d, returning %d", tid, rc);
      return rc;
}

/*
 * NAME:        txLog()
 *
 * FUNCTION:    Writes AFTER log records for all lines modified
 *              by tid for segments specified by inodes in comdata.
 *              Code assumes only WRITELOCKS are recorded in lockwords.
 *
 * PARAMETERS:
 *
 * RETURN :
 */
static int txLog(struct jfs_log * log, struct tblock * tblk, struct commit * cd)
{
      int rc = 0;
      struct inode *ip;
      lid_t lid;
      struct tlock *tlck;
      struct lrd *lrd = &cd->lrd;

      /*
       * write log record(s) for each tlock of transaction,
       */
      for (lid = tblk->next; lid; lid = tlck->next) {
            tlck = lid_to_tlock(lid);

            tlck->flag |= tlckLOG;

            /* initialize lrd common */
            ip = tlck->ip;
            lrd->aggregate = cpu_to_le32(JFS_SBI(ip->i_sb)->aggregate);
            lrd->log.redopage.fileset = cpu_to_le32(JFS_IP(ip)->fileset);
            lrd->log.redopage.inode = cpu_to_le32(ip->i_ino);

            /* write log record of page from the tlock */
            switch (tlck->type & tlckTYPE) {
            case tlckXTREE:
                  xtLog(log, tblk, lrd, tlck);
                  break;

            case tlckDTREE:
                  dtLog(log, tblk, lrd, tlck);
                  break;

            case tlckINODE:
                  diLog(log, tblk, lrd, tlck, cd);
                  break;

            case tlckMAP:
                  mapLog(log, tblk, lrd, tlck);
                  break;

            case tlckDATA:
                  dataLog(log, tblk, lrd, tlck);
                  break;

            default:
                  jfs_err("UFO tlock:0x%p", tlck);
            }
      }

      return rc;
}

/*
 *      diLog()
 *
 * function:    log inode tlock and format maplock to update bmap;
 */
static int diLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
        struct tlock * tlck, struct commit * cd)
{
      int rc = 0;
      struct metapage *mp;
      pxd_t *pxd;
      struct pxd_lock *pxdlock;

      mp = tlck->mp;

      /* initialize as REDOPAGE record format */
      lrd->log.redopage.type = cpu_to_le16(LOG_INODE);
      lrd->log.redopage.l2linesize = cpu_to_le16(L2INODESLOTSIZE);

      pxd = &lrd->log.redopage.pxd;

      /*
       *      inode after image
       */
      if (tlck->type & tlckENTRY) {
            /* log after-image for logredo(): */
            lrd->type = cpu_to_le16(LOG_REDOPAGE);
            PXDaddress(pxd, mp->index);
            PXDlength(pxd,
                    mp->logical_size >> tblk->sb->s_blocksize_bits);
            lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, tlck));

            /* mark page as homeward bound */
            tlck->flag |= tlckWRITEPAGE;
      } else if (tlck->type & tlckFREE) {
            /*
             *      free inode extent
             *
             * (pages of the freed inode extent have been invalidated and
             * a maplock for free of the extent has been formatted at
             * txLock() time);
             *
             * the tlock had been acquired on the inode allocation map page
             * (iag) that specifies the freed extent, even though the map
             * page is not itself logged, to prevent pageout of the map
             * page before the log;
             */

            /* log LOG_NOREDOINOEXT of the freed inode extent for
             * logredo() to start NoRedoPage filters, and to update
             * imap and bmap for free of the extent;
             */
            lrd->type = cpu_to_le16(LOG_NOREDOINOEXT);
            /*
             * For the LOG_NOREDOINOEXT record, we need
             * to pass the IAG number and inode extent
             * index (within that IAG) from which the
             * the extent being released.  These have been
             * passed to us in the iplist[1] and iplist[2].
             */
            lrd->log.noredoinoext.iagnum =
                cpu_to_le32((u32) (size_t) cd->iplist[1]);
            lrd->log.noredoinoext.inoext_idx =
                cpu_to_le32((u32) (size_t) cd->iplist[2]);

            pxdlock = (struct pxd_lock *) & tlck->lock;
            *pxd = pxdlock->pxd;
            lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, NULL));

            /* update bmap */
            tlck->flag |= tlckUPDATEMAP;

            /* mark page as homeward bound */
            tlck->flag |= tlckWRITEPAGE;
      } else
            jfs_err("diLog: UFO type tlck:0x%p", tlck);
#ifdef  _JFS_WIP
      /*
       *      alloc/free external EA extent
       *
       * a maplock for txUpdateMap() to update bPWMAP for alloc/free
       * of the extent has been formatted at txLock() time;
       */
      else {
            assert(tlck->type & tlckEA);

            /* log LOG_UPDATEMAP for logredo() to update bmap for
             * alloc of new (and free of old) external EA extent;
             */
            lrd->type = cpu_to_le16(LOG_UPDATEMAP);
            pxdlock = (struct pxd_lock *) & tlck->lock;
            nlock = pxdlock->index;
            for (i = 0; i < nlock; i++, pxdlock++) {
                  if (pxdlock->flag & mlckALLOCPXD)
                        lrd->log.updatemap.type =
                            cpu_to_le16(LOG_ALLOCPXD);
                  else
                        lrd->log.updatemap.type =
                            cpu_to_le16(LOG_FREEPXD);
                  lrd->log.updatemap.nxd = cpu_to_le16(1);
                  lrd->log.updatemap.pxd = pxdlock->pxd;
                  lrd->backchain =
                      cpu_to_le32(lmLog(log, tblk, lrd, NULL));
            }

            /* update bmap */
            tlck->flag |= tlckUPDATEMAP;
      }
#endif                        /* _JFS_WIP */

      return rc;
}

/*
 *      dataLog()
 *
 * function:    log data tlock
 */
static int dataLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
          struct tlock * tlck)
{
      struct metapage *mp;
      pxd_t *pxd;

      mp = tlck->mp;

      /* initialize as REDOPAGE record format */
      lrd->log.redopage.type = cpu_to_le16(LOG_DATA);
      lrd->log.redopage.l2linesize = cpu_to_le16(L2DATASLOTSIZE);

      pxd = &lrd->log.redopage.pxd;

      /* log after-image for logredo(): */
      lrd->type = cpu_to_le16(LOG_REDOPAGE);

      if (jfs_dirtable_inline(tlck->ip)) {
            /*
             * The table has been truncated, we've must have deleted
             * the last entry, so don't bother logging this
             */
            mp->lid = 0;
            grab_metapage(mp);
            metapage_homeok(mp);
            discard_metapage(mp);
            tlck->mp = NULL;
            return 0;
      }

      PXDaddress(pxd, mp->index);
      PXDlength(pxd, mp->logical_size >> tblk->sb->s_blocksize_bits);

      lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, tlck));

      /* mark page as homeward bound */
      tlck->flag |= tlckWRITEPAGE;

      return 0;
}

/*
 *      dtLog()
 *
 * function:    log dtree tlock and format maplock to update bmap;
 */
static void dtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
         struct tlock * tlck)
{
      struct metapage *mp;
      struct pxd_lock *pxdlock;
      pxd_t *pxd;

      mp = tlck->mp;

      /* initialize as REDOPAGE/NOREDOPAGE record format */
      lrd->log.redopage.type = cpu_to_le16(LOG_DTREE);
      lrd->log.redopage.l2linesize = cpu_to_le16(L2DTSLOTSIZE);

      pxd = &lrd->log.redopage.pxd;

      if (tlck->type & tlckBTROOT)
            lrd->log.redopage.type |= cpu_to_le16(LOG_BTROOT);

      /*
       *      page extension via relocation: entry insertion;
       *      page extension in-place: entry insertion;
       *      new right page from page split, reinitialized in-line
       *      root from root page split: entry insertion;
       */
      if (tlck->type & (tlckNEW | tlckEXTEND)) {
            /* log after-image of the new page for logredo():
             * mark log (LOG_NEW) for logredo() to initialize
             * freelist and update bmap for alloc of the new page;
             */
            lrd->type = cpu_to_le16(LOG_REDOPAGE);
            if (tlck->type & tlckEXTEND)
                  lrd->log.redopage.type |= cpu_to_le16(LOG_EXTEND);
            else
                  lrd->log.redopage.type |= cpu_to_le16(LOG_NEW);
            PXDaddress(pxd, mp->index);
            PXDlength(pxd,
                    mp->logical_size >> tblk->sb->s_blocksize_bits);
            lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, tlck));

            /* format a maplock for txUpdateMap() to update bPMAP for
             * alloc of the new page;
             */
            if (tlck->type & tlckBTROOT)
                  return;
            tlck->flag |= tlckUPDATEMAP;
            pxdlock = (struct pxd_lock *) & tlck->lock;
            pxdlock->flag = mlckALLOCPXD;
            pxdlock->pxd = *pxd;

            pxdlock->index = 1;

            /* mark page as homeward bound */
            tlck->flag |= tlckWRITEPAGE;
            return;
      }

      /*
       *      entry insertion/deletion,
       *      sibling page link update (old right page before split);
       */
      if (tlck->type & (tlckENTRY | tlckRELINK)) {
            /* log after-image for logredo(): */
            lrd->type = cpu_to_le16(LOG_REDOPAGE);
            PXDaddress(pxd, mp->index);
            PXDlength(pxd,
                    mp->logical_size >> tblk->sb->s_blocksize_bits);
            lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, tlck));

            /* mark page as homeward bound */
            tlck->flag |= tlckWRITEPAGE;
            return;
      }

      /*
       *      page deletion: page has been invalidated
       *      page relocation: source extent
       *
       *      a maplock for free of the page has been formatted
       *      at txLock() time);
       */
      if (tlck->type & (tlckFREE | tlckRELOCATE)) {
            /* log LOG_NOREDOPAGE of the deleted page for logredo()
             * to start NoRedoPage filter and to update bmap for free
             * of the deletd page
             */
            lrd->type = cpu_to_le16(LOG_NOREDOPAGE);
            pxdlock = (struct pxd_lock *) & tlck->lock;
            *pxd = pxdlock->pxd;
            lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, NULL));

            /* a maplock for txUpdateMap() for free of the page
             * has been formatted at txLock() time;
             */
            tlck->flag |= tlckUPDATEMAP;
      }
      return;
}

/*
 *      xtLog()
 *
 * function:    log xtree tlock and format maplock to update bmap;
 */
static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
         struct tlock * tlck)
{
      struct inode *ip;
      struct metapage *mp;
      xtpage_t *p;
      struct xtlock *xtlck;
      struct maplock *maplock;
      struct xdlistlock *xadlock;
      struct pxd_lock *pxdlock;
      pxd_t *page_pxd;
      int next, lwm, hwm;

      ip = tlck->ip;
      mp = tlck->mp;

      /* initialize as REDOPAGE/NOREDOPAGE record format */
      lrd->log.redopage.type = cpu_to_le16(LOG_XTREE);
      lrd->log.redopage.l2linesize = cpu_to_le16(L2XTSLOTSIZE);

      page_pxd = &lrd->log.redopage.pxd;

      if (tlck->type & tlckBTROOT) {
            lrd->log.redopage.type |= cpu_to_le16(LOG_BTROOT);
            p = &JFS_IP(ip)->i_xtroot;
            if (S_ISDIR(ip->i_mode))
                  lrd->log.redopage.type |=
                      cpu_to_le16(LOG_DIR_XTREE);
      } else
            p = (xtpage_t *) mp->data;
      next = le16_to_cpu(p->header.nextindex);

      xtlck = (struct xtlock *) & tlck->lock;

      maplock = (struct maplock *) & tlck->lock;
      xadlock = (struct xdlistlock *) maplock;

      /*
       *      entry insertion/extension;
       *      sibling page link update (old right page before split);
       */
      if (tlck->type & (tlckNEW | tlckGROW | tlckRELINK)) {
            /* log after-image for logredo():
             * logredo() will update bmap for alloc of new/extended
             * extents (XAD_NEW|XAD_EXTEND) of XAD[lwm:next) from
             * after-image of XADlist;
             * logredo() resets (XAD_NEW|XAD_EXTEND) flag when
             * applying the after-image to the meta-data page.
             */
            lrd->type = cpu_to_le16(LOG_REDOPAGE);
            PXDaddress(page_pxd, mp->index);
            PXDlength(page_pxd,
                    mp->logical_size >> tblk->sb->s_blocksize_bits);
            lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, tlck));

            /* format a maplock for txUpdateMap() to update bPMAP
             * for alloc of new/extended extents of XAD[lwm:next)
             * from the page itself;
             * txUpdateMap() resets (XAD_NEW|XAD_EXTEND) flag.
             */
            lwm = xtlck->lwm.offset;
            if (lwm == 0)
                  lwm = XTPAGEMAXSLOT;

            if (lwm == next)
                  goto out;
            if (lwm > next) {
                  jfs_err("xtLog: lwm > next\n");
                  goto out;
            }
            tlck->flag |= tlckUPDATEMAP;
            xadlock->flag = mlckALLOCXADLIST;
            xadlock->count = next - lwm;
            if ((xadlock->count <= 4) && (tblk->xflag & COMMIT_LAZY)) {
                  int i;
                  pxd_t *pxd;
                  /*
                   * Lazy commit may allow xtree to be modified before
                   * txUpdateMap runs.  Copy xad into linelock to
                   * preserve correct data.
                   *
                   * We can fit twice as may pxd's as xads in the lock
                   */
                  xadlock->flag = mlckALLOCPXDLIST;
                  pxd = xadlock->xdlist = &xtlck->pxdlock;
                  for (i = 0; i < xadlock->count; i++) {
                        PXDaddress(pxd, addressXAD(&p->xad[lwm + i]));
                        PXDlength(pxd, lengthXAD(&p->xad[lwm + i]));
                        p->xad[lwm + i].flag &=
                            ~(XAD_NEW | XAD_EXTENDED);
                        pxd++;
                  }
            } else {
                  /*
                   * xdlist will point to into inode's xtree, ensure
                   * that transaction is not committed lazily.
                   */
                  xadlock->flag = mlckALLOCXADLIST;
                  xadlock->xdlist = &p->xad[lwm];
                  tblk->xflag &= ~COMMIT_LAZY;
            }
            jfs_info("xtLog: alloc ip:0x%p mp:0x%p tlck:0x%p lwm:%d "
                   "count:%d", tlck->ip, mp, tlck, lwm, xadlock->count);

            maplock->index = 1;

            out:
            /* mark page as homeward bound */
            tlck->flag |= tlckWRITEPAGE;

            return;
      }

      /*
       *      page deletion: file deletion/truncation (ref. xtTruncate())
       *
       * (page will be invalidated after log is written and bmap
       * is updated from the page);
       */
      if (tlck->type & tlckFREE) {
            /* LOG_NOREDOPAGE log for NoRedoPage filter:
             * if page free from file delete, NoRedoFile filter from
             * inode image of zero link count will subsume NoRedoPage
             * filters for each page;
             * if page free from file truncattion, write NoRedoPage
             * filter;
             *
             * upadte of block allocation map for the page itself:
             * if page free from deletion and truncation, LOG_UPDATEMAP
             * log for the page itself is generated from processing
             * its parent page xad entries;
             */
            /* if page free from file truncation, log LOG_NOREDOPAGE
             * of the deleted page for logredo() to start NoRedoPage
             * filter for the page;
             */
            if (tblk->xflag & COMMIT_TRUNCATE) {
                  /* write NOREDOPAGE for the page */
                  lrd->type = cpu_to_le16(LOG_NOREDOPAGE);
                  PXDaddress(page_pxd, mp->index);
                  PXDlength(page_pxd,
                          mp->logical_size >> tblk->sb->
                          s_blocksize_bits);
                  lrd->backchain =
                      cpu_to_le32(lmLog(log, tblk, lrd, NULL));

                  if (tlck->type & tlckBTROOT) {
                        /* Empty xtree must be logged */
                        lrd->type = cpu_to_le16(LOG_REDOPAGE);
                        lrd->backchain =
                            cpu_to_le32(lmLog(log, tblk, lrd, tlck));
                  }
            }

            /* init LOG_UPDATEMAP of the freed extents
             * XAD[XTENTRYSTART:hwm) from the deleted page itself
             * for logredo() to update bmap;
             */
            lrd->type = cpu_to_le16(LOG_UPDATEMAP);
            lrd->log.updatemap.type = cpu_to_le16(LOG_FREEXADLIST);
            xtlck = (struct xtlock *) & tlck->lock;
            hwm = xtlck->hwm.offset;
            lrd->log.updatemap.nxd =
                cpu_to_le16(hwm - XTENTRYSTART + 1);
            /* reformat linelock for lmLog() */
            xtlck->header.offset = XTENTRYSTART;
            xtlck->header.length = hwm - XTENTRYSTART + 1;
            xtlck->index = 1;
            lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, tlck));

            /* format a maplock for txUpdateMap() to update bmap
             * to free extents of XAD[XTENTRYSTART:hwm) from the
             * deleted page itself;
             */
            tlck->flag |= tlckUPDATEMAP;
            xadlock->count = hwm - XTENTRYSTART + 1;
            if ((xadlock->count <= 4) && (tblk->xflag & COMMIT_LAZY)) {
                  int i;
                  pxd_t *pxd;
                  /*
                   * Lazy commit may allow xtree to be modified before
                   * txUpdateMap runs.  Copy xad into linelock to
                   * preserve correct data.
                   *
                   * We can fit twice as may pxd's as xads in the lock
                   */
                  xadlock->flag = mlckFREEPXDLIST;
                  pxd = xadlock->xdlist = &xtlck->pxdlock;
                  for (i = 0; i < xadlock->count; i++) {
                        PXDaddress(pxd,
                              addressXAD(&p->xad[XTENTRYSTART + i]));
                        PXDlength(pxd,
                              lengthXAD(&p->xad[XTENTRYSTART + i]));
                        pxd++;
                  }
            } else {
                  /*
                   * xdlist will point to into inode's xtree, ensure
                   * that transaction is not committed lazily.
                   */
                  xadlock->flag = mlckFREEXADLIST;
                  xadlock->xdlist = &p->xad[XTENTRYSTART];
                  tblk->xflag &= ~COMMIT_LAZY;
            }
            jfs_info("xtLog: free ip:0x%p mp:0x%p count:%d lwm:2",
                   tlck->ip, mp, xadlock->count);

            maplock->index = 1;

            /* mark page as invalid */
            if (((tblk->xflag & COMMIT_PWMAP) || S_ISDIR(ip->i_mode))
                && !(tlck->type & tlckBTROOT))
                  tlck->flag |= tlckFREEPAGE;
            /*
               else (tblk->xflag & COMMIT_PMAP)
               ? release the page;
             */
            return;
      }

      /*
       *      page/entry truncation: file truncation (ref. xtTruncate())
       *
       *     |----------+------+------+---------------|
       *                |      |      |
       *                |      |     hwm - hwm before truncation
       *                |     next - truncation point
       *               lwm - lwm before truncation
       * header ?
       */
      if (tlck->type & tlckTRUNCATE) {
            pxd_t pxd;  /* truncated extent of xad */
            int twm;

            /*
             * For truncation the entire linelock may be used, so it would
             * be difficult to store xad list in linelock itself.
             * Therefore, we'll just force transaction to be committed
             * synchronously, so that xtree pages won't be changed before
             * txUpdateMap runs.
             */
            tblk->xflag &= ~COMMIT_LAZY;
            lwm = xtlck->lwm.offset;
            if (lwm == 0)
                  lwm = XTPAGEMAXSLOT;
            hwm = xtlck->hwm.offset;
            twm = xtlck->twm.offset;

            /*
             *      write log records
             */
            /* log after-image for logredo():
             *
             * logredo() will update bmap for alloc of new/extended
             * extents (XAD_NEW|XAD_EXTEND) of XAD[lwm:next) from
             * after-image of XADlist;
             * logredo() resets (XAD_NEW|XAD_EXTEND) flag when
             * applying the after-image to the meta-data page.
             */
            lrd->type = cpu_to_le16(LOG_REDOPAGE);
            PXDaddress(page_pxd, mp->index);
            PXDlength(page_pxd,
                    mp->logical_size >> tblk->sb->s_blocksize_bits);
            lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, tlck));

            /*
             * truncate entry XAD[twm == next - 1]:
             */
            if (twm == next - 1) {
                  /* init LOG_UPDATEMAP for logredo() to update bmap for
                   * free of truncated delta extent of the truncated
                   * entry XAD[next - 1]:
                   * (xtlck->pxdlock = truncated delta extent);
                   */
                  pxdlock = (struct pxd_lock *) & xtlck->pxdlock;
                  /* assert(pxdlock->type & tlckTRUNCATE); */
                  lrd->type = cpu_to_le16(LOG_UPDATEMAP);
                  lrd->log.updatemap.type = cpu_to_le16(LOG_FREEPXD);
                  lrd->log.updatemap.nxd = cpu_to_le16(1);
                  lrd->log.updatemap.pxd = pxdlock->pxd;
                  pxd = pxdlock->pxd;     /* save to format maplock */
                  lrd->backchain =
                      cpu_to_le32(lmLog(log, tblk, lrd, NULL));
            }

            /*
             * free entries XAD[next:hwm]:
             */
            if (hwm >= next) {
                  /* init LOG_UPDATEMAP of the freed extents
                   * XAD[next:hwm] from the deleted page itself
                   * for logredo() to update bmap;
                   */
                  lrd->type = cpu_to_le16(LOG_UPDATEMAP);
                  lrd->log.updatemap.type =
                      cpu_to_le16(LOG_FREEXADLIST);
                  xtlck = (struct xtlock *) & tlck->lock;
                  hwm = xtlck->hwm.offset;
                  lrd->log.updatemap.nxd =
                      cpu_to_le16(hwm - next + 1);
                  /* reformat linelock for lmLog() */
                  xtlck->header.offset = next;
                  xtlck->header.length = hwm - next + 1;
                  xtlck->index = 1;
                  lrd->backchain =
                      cpu_to_le32(lmLog(log, tblk, lrd, tlck));
            }

            /*
             *      format maplock(s) for txUpdateMap() to update bmap
             */
            maplock->index = 0;

            /*
             * allocate entries XAD[lwm:next):
             */
            if (lwm < next) {
                  /* format a maplock for txUpdateMap() to update bPMAP
                   * for alloc of new/extended extents of XAD[lwm:next)
                   * from the page itself;
                   * txUpdateMap() resets (XAD_NEW|XAD_EXTEND) flag.
                   */
                  tlck->flag |= tlckUPDATEMAP;
                  xadlock->flag = mlckALLOCXADLIST;
                  xadlock->count = next - lwm;
                  xadlock->xdlist = &p->xad[lwm];

                  jfs_info("xtLog: alloc ip:0x%p mp:0x%p count:%d "
                         "lwm:%d next:%d",
                         tlck->ip, mp, xadlock->count, lwm, next);
                  maplock->index++;
                  xadlock++;
            }

            /*
             * truncate entry XAD[twm == next - 1]:
             */
            if (twm == next - 1) {
                  struct pxd_lock *pxdlock;

                  /* format a maplock for txUpdateMap() to update bmap
                   * to free truncated delta extent of the truncated
                   * entry XAD[next - 1];
                   * (xtlck->pxdlock = truncated delta extent);
                   */
                  tlck->flag |= tlckUPDATEMAP;
                  pxdlock = (struct pxd_lock *) xadlock;
                  pxdlock->flag = mlckFREEPXD;
                  pxdlock->count = 1;
                  pxdlock->pxd = pxd;

                  jfs_info("xtLog: truncate ip:0x%p mp:0x%p count:%d "
                         "hwm:%d", ip, mp, pxdlock->count, hwm);
                  maplock->index++;
                  xadlock++;
            }

            /*
             * free entries XAD[next:hwm]:
             */
            if (hwm >= next) {
                  /* format a maplock for txUpdateMap() to update bmap
                   * to free extents of XAD[next:hwm] from thedeleted
                   * page itself;
                   */
                  tlck->flag |= tlckUPDATEMAP;
                  xadlock->flag = mlckFREEXADLIST;
                  xadlock->count = hwm - next + 1;
                  xadlock->xdlist = &p->xad[next];

                  jfs_info("xtLog: free ip:0x%p mp:0x%p count:%d "
                         "next:%d hwm:%d",
                         tlck->ip, mp, xadlock->count, next, hwm);
                  maplock->index++;
            }

            /* mark page as homeward bound */
            tlck->flag |= tlckWRITEPAGE;
      }
      return;
}

/*
 *      mapLog()
 *
 * function:    log from maplock of freed data extents;
 */
static void mapLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
               struct tlock * tlck)
{
      struct pxd_lock *pxdlock;
      int i, nlock;
      pxd_t *pxd;

      /*
       *      page relocation: free the source page extent
       *
       * a maplock for txUpdateMap() for free of the page
       * has been formatted at txLock() time saving the src
       * relocated page address;
       */
      if (tlck->type & tlckRELOCATE) {
            /* log LOG_NOREDOPAGE of the old relocated page
             * for logredo() to start NoRedoPage filter;
             */
            lrd->type = cpu_to_le16(LOG_NOREDOPAGE);
            pxdlock = (struct pxd_lock *) & tlck->lock;
            pxd = &lrd->log.redopage.pxd;
            *pxd = pxdlock->pxd;
            lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, NULL));

            /* (N.B. currently, logredo() does NOT update bmap
             * for free of the page itself for (LOG_XTREE|LOG_NOREDOPAGE);
             * if page free from relocation, LOG_UPDATEMAP log is
             * specifically generated now for logredo()
             * to update bmap for free of src relocated page;
             * (new flag LOG_RELOCATE may be introduced which will
             * inform logredo() to start NORedoPage filter and also
             * update block allocation map at the same time, thus
             * avoiding an extra log write);
             */
            lrd->type = cpu_to_le16(LOG_UPDATEMAP);
            lrd->log.updatemap.type = cpu_to_le16(LOG_FREEPXD);
            lrd->log.updatemap.nxd = cpu_to_le16(1);
            lrd->log.updatemap.pxd = pxdlock->pxd;
            lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, NULL));

            /* a maplock for txUpdateMap() for free of the page
             * has been formatted at txLock() time;
             */
            tlck->flag |= tlckUPDATEMAP;
            return;
      }
      /*

       * Otherwise it's not a relocate request
       *
       */
      else {
            /* log LOG_UPDATEMAP for logredo() to update bmap for
             * free of truncated/relocated delta extent of the data;
             * e.g.: external EA extent, relocated/truncated extent
             * from xtTailgate();
             */
            lrd->type = cpu_to_le16(LOG_UPDATEMAP);
            pxdlock = (struct pxd_lock *) & tlck->lock;
            nlock = pxdlock->index;
            for (i = 0; i < nlock; i++, pxdlock++) {
                  if (pxdlock->flag & mlckALLOCPXD)
                        lrd->log.updatemap.type =
                            cpu_to_le16(LOG_ALLOCPXD);
                  else
                        lrd->log.updatemap.type =
                            cpu_to_le16(LOG_FREEPXD);
                  lrd->log.updatemap.nxd = cpu_to_le16(1);
                  lrd->log.updatemap.pxd = pxdlock->pxd;
                  lrd->backchain =
                      cpu_to_le32(lmLog(log, tblk, lrd, NULL));
                  jfs_info("mapLog: xaddr:0x%lx xlen:0x%x",
                         (ulong) addressPXD(&pxdlock->pxd),
                         lengthPXD(&pxdlock->pxd));
            }

            /* update bmap */
            tlck->flag |= tlckUPDATEMAP;
      }
}

/*
 *      txEA()
 *
 * function:    acquire maplock for EA/ACL extents or
 *              set COMMIT_INLINE flag;
 */
void txEA(tid_t tid, struct inode *ip, dxd_t * oldea, dxd_t * newea)
{
      struct tlock *tlck = NULL;
      struct pxd_lock *maplock = NULL, *pxdlock = NULL;

      /*
       * format maplock for alloc of new EA extent
       */
      if (newea) {
            /* Since the newea could be a completely zeroed entry we need to
             * check for the two flags which indicate we should actually
             * commit new EA data
             */
            if (newea->flag & DXD_EXTENT) {
                  tlck = txMaplock(tid, ip, tlckMAP);
                  maplock = (struct pxd_lock *) & tlck->lock;
                  pxdlock = (struct pxd_lock *) maplock;
                  pxdlock->flag = mlckALLOCPXD;
                  PXDaddress(&pxdlock->pxd, addressDXD(newea));
                  PXDlength(&pxdlock->pxd, lengthDXD(newea));
                  pxdlock++;
                  maplock->index = 1;
            } else if (newea->flag & DXD_INLINE) {
                  tlck = NULL;

                  set_cflag(COMMIT_Inlineea, ip);
            }
      }

      /*
       * format maplock for free of old EA extent
       */
      if (!test_cflag(COMMIT_Nolink, ip) && oldea->flag & DXD_EXTENT) {
            if (tlck == NULL) {
                  tlck = txMaplock(tid, ip, tlckMAP);
                  maplock = (struct pxd_lock *) & tlck->lock;
                  pxdlock = (struct pxd_lock *) maplock;
                  maplock->index = 0;
            }
            pxdlock->flag = mlckFREEPXD;
            PXDaddress(&pxdlock->pxd, addressDXD(oldea));
            PXDlength(&pxdlock->pxd, lengthDXD(oldea));
            maplock->index++;
      }
}

/*
 *      txForce()
 *
 * function: synchronously write pages locked by transaction
 *              after txLog() but before txUpdateMap();
 */
static void txForce(struct tblock * tblk)
{
      struct tlock *tlck;
      lid_t lid, next;
      struct metapage *mp;

      /*
       * reverse the order of transaction tlocks in
       * careful update order of address index pages
       * (right to left, bottom up)
       */
      tlck = lid_to_tlock(tblk->next);
      lid = tlck->next;
      tlck->next = 0;
      while (lid) {
            tlck = lid_to_tlock(lid);
            next = tlck->next;
            tlck->next = tblk->next;
            tblk->next = lid;
            lid = next;
      }

      /*
       * synchronously write the page, and
       * hold the page for txUpdateMap();
       */
      for (lid = tblk->next; lid; lid = next) {
            tlck = lid_to_tlock(lid);
            next = tlck->next;

            if ((mp = tlck->mp) != NULL &&
                (tlck->type & tlckBTROOT) == 0) {
                  assert(mp->xflag & COMMIT_PAGE);

                  if (tlck->flag & tlckWRITEPAGE) {
                        tlck->flag &= ~tlckWRITEPAGE;

                        /* do not release page to freelist */
                        force_metapage(mp);
#if 0
                        /*
                         * The "right" thing to do here is to
                         * synchronously write the metadata.
                         * With the current implementation this
                         * is hard since write_metapage requires
                         * us to kunmap & remap the page.  If we
                         * have tlocks pointing into the metadata
                         * pages, we don't want to do this.  I think
                         * we can get by with synchronously writing
                         * the pages when they are released.
                         */
                        assert(mp->nohomeok);
                        set_bit(META_dirty, &mp->flag);
                        set_bit(META_sync, &mp->flag);
#endif
                  }
            }
      }
}

/*
 *      txUpdateMap()
 *
 * function:    update persistent allocation map (and working map
 *              if appropriate);
 *
 * parameter:
 */
static void txUpdateMap(struct tblock * tblk)
{
      struct inode *ip;
      struct inode *ipimap;
      lid_t lid;
      struct tlock *tlck;
      struct maplock *maplock;
      struct pxd_lock pxdlock;
      int maptype;
      int k, nlock;
      struct metapage *mp = NULL;

      ipimap = JFS_SBI(tblk->sb)->ipimap;

      maptype = (tblk->xflag & COMMIT_PMAP) ? COMMIT_PMAP : COMMIT_PWMAP;


      /*
       *      update block allocation map
       *
       * update allocation state in pmap (and wmap) and
       * update lsn of the pmap page;
       */
      /*
       * scan each tlock/page of transaction for block allocation/free:
       *
       * for each tlock/page of transaction, update map.
       *  ? are there tlock for pmap and pwmap at the same time ?
       */
      for (lid = tblk->next; lid; lid = tlck->next) {
            tlck = lid_to_tlock(lid);

            if ((tlck->flag & tlckUPDATEMAP) == 0)
                  continue;

            if (tlck->flag & tlckFREEPAGE) {
                  /*
                   * Another thread may attempt to reuse freed space
                   * immediately, so we want to get rid of the metapage
                   * before anyone else has a chance to get it.
                   * Lock metapage, update maps, then invalidate
                   * the metapage.
                   */
                  mp = tlck->mp;
                  ASSERT(mp->xflag & COMMIT_PAGE);
                  grab_metapage(mp);
            }

            /*
             * extent list:
             * . in-line PXD list:
             * . out-of-line XAD list:
             */
            maplock = (struct maplock *) & tlck->lock;
            nlock = maplock->index;

            for (k = 0; k < nlock; k++, maplock++) {
                  /*
                   * allocate blocks in persistent map:
                   *
                   * blocks have been allocated from wmap at alloc time;
                   */
                  if (maplock->flag & mlckALLOC) {
                        txAllocPMap(ipimap, maplock, tblk);
                  }
                  /*
                   * free blocks in persistent and working map:
                   * blocks will be freed in pmap and then in wmap;
                   *
                   * ? tblock specifies the PMAP/PWMAP based upon
                   * transaction
                   *
                   * free blocks in persistent map:
                   * blocks will be freed from wmap at last reference
                   * release of the object for regular files;
                   *
                   * Alway free blocks from both persistent & working
                   * maps for directories
                   */
                  else {      /* (maplock->flag & mlckFREE) */

                        if (tlck->flag & tlckDIRECTORY)
                              txFreeMap(ipimap, maplock,
                                      tblk, COMMIT_PWMAP);
                        else
                              txFreeMap(ipimap, maplock,
                                      tblk, maptype);
                  }
            }
            if (tlck->flag & tlckFREEPAGE) {
                  if (!(tblk->flag & tblkGC_LAZY)) {
                        /* This is equivalent to txRelease */
                        ASSERT(mp->lid == lid);
                        tlck->mp->lid = 0;
                  }
                  assert(mp->nohomeok == 1);
                  metapage_homeok(mp);
                  discard_metapage(mp);
                  tlck->mp = NULL;
            }
      }
      /*
       *      update inode allocation map
       *
       * update allocation state in pmap and
       * update lsn of the pmap page;
       * update in-memory inode flag/state
       *
       * unlock mapper/write lock
       */
      if (tblk->xflag & COMMIT_CREATE) {
            diUpdatePMap(ipimap, tblk->ino, FALSE, tblk);
            /* update persistent block allocation map
             * for the allocation of inode extent;
             */
            pxdlock.flag = mlckALLOCPXD;
            pxdlock.pxd = tblk->u.ixpxd;
            pxdlock.index = 1;
            txAllocPMap(ipimap, (struct maplock *) & pxdlock, tblk);
      } else if (tblk->xflag & COMMIT_DELETE) {
            ip = tblk->u.ip;
            diUpdatePMap(ipimap, ip->i_ino, TRUE, tblk);
            iput(ip);
      }
}

/*
 *      txAllocPMap()
 *
 * function: allocate from persistent map;
 *
 * parameter:
 *      ipbmap  -
 *      malock -
 *              xad list:
 *              pxd:
 *
 *      maptype -
 *              allocate from persistent map;
 *              free from persistent map;
 *              (e.g., tmp file - free from working map at releae
 *               of last reference);
 *              free from persistent and working map;
 *
 *      lsn     - log sequence number;
 */
static void txAllocPMap(struct inode *ip, struct maplock * maplock,
                  struct tblock * tblk)
{
      struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
      struct xdlistlock *xadlistlock;
      xad_t *xad;
      s64 xaddr;
      int xlen;
      struct pxd_lock *pxdlock;
      struct xdlistlock *pxdlistlock;
      pxd_t *pxd;
      int n;

      /*
       * allocate from persistent map;
       */
      if (maplock->flag & mlckALLOCXADLIST) {
            xadlistlock = (struct xdlistlock *) maplock;
            xad = xadlistlock->xdlist;
            for (n = 0; n < xadlistlock->count; n++, xad++) {
                  if (xad->flag & (XAD_NEW | XAD_EXTENDED)) {
                        xaddr = addressXAD(xad);
                        xlen = lengthXAD(xad);
                        dbUpdatePMap(ipbmap, FALSE, xaddr,
                                   (s64) xlen, tblk);
                        xad->flag &= ~(XAD_NEW | XAD_EXTENDED);
                        jfs_info("allocPMap: xaddr:0x%lx xlen:%d",
                               (ulong) xaddr, xlen);
                  }
            }
      } else if (maplock->flag & mlckALLOCPXD) {
            pxdlock = (struct pxd_lock *) maplock;
            xaddr = addressPXD(&pxdlock->pxd);
            xlen = lengthPXD(&pxdlock->pxd);
            dbUpdatePMap(ipbmap, FALSE, xaddr, (s64) xlen, tblk);
            jfs_info("allocPMap: xaddr:0x%lx xlen:%d", (ulong) xaddr, xlen);
      } else {          /* (maplock->flag & mlckALLOCPXDLIST) */

            pxdlistlock = (struct xdlistlock *) maplock;
            pxd = pxdlistlock->xdlist;
            for (n = 0; n < pxdlistlock->count; n++, pxd++) {
                  xaddr = addressPXD(pxd);
                  xlen = lengthPXD(pxd);
                  dbUpdatePMap(ipbmap, FALSE, xaddr, (s64) xlen,
                             tblk);
                  jfs_info("allocPMap: xaddr:0x%lx xlen:%d",
                         (ulong) xaddr, xlen);
            }
      }
}

/*
 *      txFreeMap()
 *
 * function:    free from persistent and/or working map;
 *
 * todo: optimization
 */
void txFreeMap(struct inode *ip,
             struct maplock * maplock, struct tblock * tblk, int maptype)
{
      struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
      struct xdlistlock *xadlistlock;
      xad_t *xad;
      s64 xaddr;
      int xlen;
      struct pxd_lock *pxdlock;
      struct xdlistlock *pxdlistlock;
      pxd_t *pxd;
      int n;

      jfs_info("txFreeMap: tblk:0x%p maplock:0x%p maptype:0x%x",
             tblk, maplock, maptype);

      /*
       * free from persistent map;
       */
      if (maptype == COMMIT_PMAP || maptype == COMMIT_PWMAP) {
            if (maplock->flag & mlckFREEXADLIST) {
                  xadlistlock = (struct xdlistlock *) maplock;
                  xad = xadlistlock->xdlist;
                  for (n = 0; n < xadlistlock->count; n++, xad++) {
                        if (!(xad->flag & XAD_NEW)) {
                              xaddr = addressXAD(xad);
                              xlen = lengthXAD(xad);
                              dbUpdatePMap(ipbmap, TRUE, xaddr,
                                         (s64) xlen, tblk);
                              jfs_info("freePMap: xaddr:0x%lx "
                                     "xlen:%d",
                                     (ulong) xaddr, xlen);
                        }
                  }
            } else if (maplock->flag & mlckFREEPXD) {
                  pxdlock = (struct pxd_lock *) maplock;
                  xaddr = addressPXD(&pxdlock->pxd);
                  xlen = lengthPXD(&pxdlock->pxd);
                  dbUpdatePMap(ipbmap, TRUE, xaddr, (s64) xlen,
                             tblk);
                  jfs_info("freePMap: xaddr:0x%lx xlen:%d",
                         (ulong) xaddr, xlen);
            } else {    /* (maplock->flag & mlckALLOCPXDLIST) */

                  pxdlistlock = (struct xdlistlock *) maplock;
                  pxd = pxdlistlock->xdlist;
                  for (n = 0; n < pxdlistlock->count; n++, pxd++) {
                        xaddr = addressPXD(pxd);
                        xlen = lengthPXD(pxd);
                        dbUpdatePMap(ipbmap, TRUE, xaddr,
                                   (s64) xlen, tblk);
                        jfs_info("freePMap: xaddr:0x%lx xlen:%d",
                               (ulong) xaddr, xlen);
                  }
            }
      }

      /*
       * free from working map;
       */
      if (maptype == COMMIT_PWMAP || maptype == COMMIT_WMAP) {
            if (maplock->flag & mlckFREEXADLIST) {
                  xadlistlock = (struct xdlistlock *) maplock;
                  xad = xadlistlock->xdlist;
                  for (n = 0; n < xadlistlock->count; n++, xad++) {
                        xaddr = addressXAD(xad);
                        xlen = lengthXAD(xad);
                        dbFree(ip, xaddr, (s64) xlen);
                        xad->flag = 0;
                        jfs_info("freeWMap: xaddr:0x%lx xlen:%d",
                               (ulong) xaddr, xlen);
                  }
            } else if (maplock->flag & mlckFREEPXD) {
                  pxdlock = (struct pxd_lock *) maplock;
                  xaddr = addressPXD(&pxdlock->pxd);
                  xlen = lengthPXD(&pxdlock->pxd);
                  dbFree(ip, xaddr, (s64) xlen);
                  jfs_info("freeWMap: xaddr:0x%lx xlen:%d",
                         (ulong) xaddr, xlen);
            } else {    /* (maplock->flag & mlckFREEPXDLIST) */

                  pxdlistlock = (struct xdlistlock *) maplock;
                  pxd = pxdlistlock->xdlist;
                  for (n = 0; n < pxdlistlock->count; n++, pxd++) {
                        xaddr = addressPXD(pxd);
                        xlen = lengthPXD(pxd);
                        dbFree(ip, xaddr, (s64) xlen);
                        jfs_info("freeWMap: xaddr:0x%lx xlen:%d",
                               (ulong) xaddr, xlen);
                  }
            }
      }
}

/*
 *      txFreelock()
 *
 * function:    remove tlock from inode anonymous locklist
 */
void txFreelock(struct inode *ip)
{
      struct jfs_inode_info *jfs_ip = JFS_IP(ip);
      struct tlock *xtlck, *tlck;
      lid_t xlid = 0, lid;

      if (!jfs_ip->atlhead)
            return;

      TXN_LOCK();
      xtlck = (struct tlock *) &jfs_ip->atlhead;

      while ((lid = xtlck->next) != 0) {
            tlck = lid_to_tlock(lid);
            if (tlck->flag & tlckFREELOCK) {
                  xtlck->next = tlck->next;
                  txLockFree(lid);
            } else {
                  xtlck = tlck;
                  xlid = lid;
            }
      }

      if (jfs_ip->atlhead)
            jfs_ip->atltail = xlid;
      else {
            jfs_ip->atltail = 0;
            /*
             * If inode was on anon_list, remove it
             */
            list_del_init(&jfs_ip->anon_inode_list);
      }
      TXN_UNLOCK();
}

/*
 *      txAbort()
 *
 * function: abort tx before commit;
 *
 * frees line-locks and segment locks for all
 * segments in comdata structure.
 * Optionally sets state of file-system to FM_DIRTY in super-block.
 * log age of page-frames in memory for which caller has
 * are reset to 0 (to avoid logwarap).
 */
void txAbort(tid_t tid, int dirty)
{
      lid_t lid, next;
      struct metapage *mp;
      struct tblock *tblk = tid_to_tblock(tid);
      struct tlock *tlck;

      /*
       * free tlocks of the transaction
       */
      for (lid = tblk->next; lid; lid = next) {
            tlck = lid_to_tlock(lid);
            next = tlck->next;
            mp = tlck->mp;
            JFS_IP(tlck->ip)->xtlid = 0;

            if (mp) {
                  mp->lid = 0;

                  /*
                   * reset lsn of page to avoid logwarap:
                   *
                   * (page may have been previously committed by another
                   * transaction(s) but has not been paged, i.e.,
                   * it may be on logsync list even though it has not
                   * been logged for the current tx.)
                   */
                  if (mp->xflag & COMMIT_PAGE && mp->lsn)
                        LogSyncRelease(mp);
            }
            /* insert tlock at head of freelist */
            TXN_LOCK();
            txLockFree(lid);
            TXN_UNLOCK();
      }

      /* caller will free the transaction block */

      tblk->next = tblk->last = 0;

      /*
       * mark filesystem dirty
       */
      if (dirty)
            jfs_error(tblk->sb, "txAbort");

      return;
}

/*
 *      txLazyCommit(void)
 *
 *    All transactions except those changing ipimap (COMMIT_FORCE) are
 *    processed by this routine.  This insures that the inode and block
 *    allocation maps are updated in order.  For synchronous transactions,
 *    let the user thread finish processing after txUpdateMap() is called.
 */
static void txLazyCommit(struct tblock * tblk)
{
      struct jfs_log *log;

      while (((tblk->flag & tblkGC_READY) == 0) &&
             ((tblk->flag & tblkGC_UNLOCKED) == 0)) {
            /* We must have gotten ahead of the user thread
             */
            jfs_info("jfs_lazycommit: tblk 0x%p not unlocked", tblk);
            yield();
      }

      jfs_info("txLazyCommit: processing tblk 0x%p", tblk);

      txUpdateMap(tblk);

      log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;

      spin_lock_irq(&log->gclock);  // LOGGC_LOCK

      tblk->flag |= tblkGC_COMMITTED;

      if (tblk->flag & tblkGC_READY)
            log->gcrtc--;

      wake_up_all(&tblk->gcwait);   // LOGGC_WAKEUP

      /*
       * Can't release log->gclock until we've tested tblk->flag
       */
      if (tblk->flag & tblkGC_LAZY) {
            spin_unlock_irq(&log->gclock);      // LOGGC_UNLOCK
            txUnlock(tblk);
            tblk->flag &= ~tblkGC_LAZY;
            txEnd(tblk - TxBlock);  /* Convert back to tid */
      } else
            spin_unlock_irq(&log->gclock);      // LOGGC_UNLOCK

      jfs_info("txLazyCommit: done: tblk = 0x%p", tblk);
}

/*
 *      jfs_lazycommit(void)
 *
 *    To be run as a kernel daemon.  If lbmIODone is called in an interrupt
 *    context, or where blocking is not wanted, this routine will process
 *    committed transactions from the unlock queue.
 */
int jfs_lazycommit(void *arg)
{
      int WorkDone;
      struct tblock *tblk;
      unsigned long flags;
      struct jfs_sb_info *sbi;

      do {
            LAZY_LOCK(flags);
            jfs_commit_thread_waking = 0; /* OK to wake another thread */
            while (!list_empty(&TxAnchor.unlock_queue)) {
                  WorkDone = 0;
                  list_for_each_entry(tblk, &TxAnchor.unlock_queue,
                                  cqueue) {

                        sbi = JFS_SBI(tblk->sb);
                        /*
                         * For each volume, the transactions must be
                         * handled in order.  If another commit thread
                         * is handling a tblk for this superblock,
                         * skip it
                         */
                        if (sbi->commit_state & IN_LAZYCOMMIT)
                              continue;

                        sbi->commit_state |= IN_LAZYCOMMIT;
                        WorkDone = 1;

                        /*
                         * Remove transaction from queue
                         */
                        list_del(&tblk->cqueue);

                        LAZY_UNLOCK(flags);
                        txLazyCommit(tblk);
                        LAZY_LOCK(flags);

                        sbi->commit_state &= ~IN_LAZYCOMMIT;
                        /*
                         * Don't continue in the for loop.  (We can't
                         * anyway, it's unsafe!)  We want to go back to
                         * the beginning of the list.
                         */
                        break;
                  }

                  /* If there was nothing to do, don't continue */
                  if (!WorkDone)
                        break;
            }
            /* In case a wakeup came while all threads were active */
            jfs_commit_thread_waking = 0;

            if (freezing(current)) {
                  LAZY_UNLOCK(flags);
                  refrigerator();
            } else {
                  DECLARE_WAITQUEUE(wq, current);

                  add_wait_queue(&jfs_commit_thread_wait, &wq);
                  set_current_state(TASK_INTERRUPTIBLE);
                  LAZY_UNLOCK(flags);
                  schedule();
                  current->state = TASK_RUNNING;
                  remove_wait_queue(&jfs_commit_thread_wait, &wq);
            }
      } while (!kthread_should_stop());

      if (!list_empty(&TxAnchor.unlock_queue))
            jfs_err("jfs_lazycommit being killed w/pending transactions!");
      else
            jfs_info("jfs_lazycommit being killed\n");
      return 0;
}

void txLazyUnlock(struct tblock * tblk)
{
      unsigned long flags;

      LAZY_LOCK(flags);

      list_add_tail(&tblk->cqueue, &TxAnchor.unlock_queue);
      /*
       * Don't wake up a commit thread if there is already one servicing
       * this superblock, or if the last one we woke up hasn't started yet.
       */
      if (!(JFS_SBI(tblk->sb)->commit_state & IN_LAZYCOMMIT) &&
          !jfs_commit_thread_waking) {
            jfs_commit_thread_waking = 1;
            wake_up(&jfs_commit_thread_wait);
      }
      LAZY_UNLOCK(flags);
}

static void LogSyncRelease(struct metapage * mp)
{
      struct jfs_log *log = mp->log;

      assert(mp->nohomeok);
      assert(log);
      metapage_homeok(mp);
}

/*
 *    txQuiesce
 *
 *    Block all new transactions and push anonymous transactions to
 *    completion
 *
 *    This does almost the same thing as jfs_sync below.  We don't
 *    worry about deadlocking when jfs_tlocks_low is set, since we would
 *    expect jfs_sync to get us out of that jam.
 */
void txQuiesce(struct super_block *sb)
{
      struct inode *ip;
      struct jfs_inode_info *jfs_ip;
      struct jfs_log *log = JFS_SBI(sb)->log;
      tid_t tid;

      set_bit(log_QUIESCE, &log->flag);

      TXN_LOCK();
restart:
      while (!list_empty(&TxAnchor.anon_list)) {
            jfs_ip = list_entry(TxAnchor.anon_list.next,
                            struct jfs_inode_info,
                            anon_inode_list);
            ip = &jfs_ip->vfs_inode;

            /*
             * inode will be removed from anonymous list
             * when it is committed
             */
            TXN_UNLOCK();
            tid = txBegin(ip->i_sb, COMMIT_INODE | COMMIT_FORCE);
            mutex_lock(&jfs_ip->commit_mutex);
            txCommit(tid, 1, &ip, 0);
            txEnd(tid);
            mutex_unlock(&jfs_ip->commit_mutex);
            /*
             * Just to be safe.  I don't know how
             * long we can run without blocking
             */
            cond_resched();
            TXN_LOCK();
      }

      /*
       * If jfs_sync is running in parallel, there could be some inodes
       * on anon_list2.  Let's check.
       */
      if (!list_empty(&TxAnchor.anon_list2)) {
            list_splice(&TxAnchor.anon_list2, &TxAnchor.anon_list);
            INIT_LIST_HEAD(&TxAnchor.anon_list2);
            goto restart;
      }
      TXN_UNLOCK();

      /*
       * We may need to kick off the group commit
       */
      jfs_flush_journal(log, 0);
}

/*
 * txResume()
 *
 * Allows transactions to start again following txQuiesce
 */
void txResume(struct super_block *sb)
{
      struct jfs_log *log = JFS_SBI(sb)->log;

      clear_bit(log_QUIESCE, &log->flag);
      TXN_WAKEUP(&log->syncwait);
}

/*
 *      jfs_sync(void)
 *
 *    To be run as a kernel daemon.  This is awakened when tlocks run low.
 *    We write any inodes that have anonymous tlocks so they will become
 *    available.
 */
int jfs_sync(void *arg)
{
      struct inode *ip;
      struct jfs_inode_info *jfs_ip;
      int rc;
      tid_t tid;

      do {
            /*
             * write each inode on the anonymous inode list
             */
            TXN_LOCK();
            while (jfs_tlocks_low && !list_empty(&TxAnchor.anon_list)) {
                  jfs_ip = list_entry(TxAnchor.anon_list.next,
                                  struct jfs_inode_info,
                                  anon_inode_list);
                  ip = &jfs_ip->vfs_inode;

                  if (! igrab(ip)) {
                        /*
                         * Inode is being freed
                         */
                        list_del_init(&jfs_ip->anon_inode_list);
                  } else if (mutex_trylock(&jfs_ip->commit_mutex)) {
                        /*
                         * inode will be removed from anonymous list
                         * when it is committed
                         */
                        TXN_UNLOCK();
                        tid = txBegin(ip->i_sb, COMMIT_INODE);
                        rc = txCommit(tid, 1, &ip, 0);
                        txEnd(tid);
                        mutex_unlock(&jfs_ip->commit_mutex);

                        iput(ip);
                        /*
                         * Just to be safe.  I don't know how
                         * long we can run without blocking
                         */
                        cond_resched();
                        TXN_LOCK();
                  } else {
                        /* We can't get the commit mutex.  It may
                         * be held by a thread waiting for tlock's
                         * so let's not block here.  Save it to
                         * put back on the anon_list.
                         */

                        /* Take off anon_list */
                        list_del(&jfs_ip->anon_inode_list);

                        /* Put on anon_list2 */
                        list_add(&jfs_ip->anon_inode_list,
                               &TxAnchor.anon_list2);

                        TXN_UNLOCK();
                        iput(ip);
                        TXN_LOCK();
                  }
            }
            /* Add anon_list2 back to anon_list */
            list_splice_init(&TxAnchor.anon_list2, &TxAnchor.anon_list);

            if (freezing(current)) {
                  TXN_UNLOCK();
                  refrigerator();
            } else {
                  set_current_state(TASK_INTERRUPTIBLE);
                  TXN_UNLOCK();
                  schedule();
                  current->state = TASK_RUNNING;
            }
      } while (!kthread_should_stop());

      jfs_info("jfs_sync being killed");
      return 0;
}

#if defined(CONFIG_PROC_FS) && defined(CONFIG_JFS_DEBUG)
int jfs_txanchor_read(char *buffer, char **start, off_t offset, int length,
                  int *eof, void *data)
{
      int len = 0;
      off_t begin;
      char *freewait;
      char *freelockwait;
      char *lowlockwait;

      freewait =
          waitqueue_active(&TxAnchor.freewait) ? "active" : "empty";
      freelockwait =
          waitqueue_active(&TxAnchor.freelockwait) ? "active" : "empty";
      lowlockwait =
          waitqueue_active(&TxAnchor.lowlockwait) ? "active" : "empty";

      len += sprintf(buffer,
                   "JFS TxAnchor\n"
                   "============\n"
                   "freetid = %d\n"
                   "freewait = %s\n"
                   "freelock = %d\n"
                   "freelockwait = %s\n"
                   "lowlockwait = %s\n"
                   "tlocksInUse = %d\n"
                   "jfs_tlocks_low = %d\n"
                   "unlock_queue is %sempty\n",
                   TxAnchor.freetid,
                   freewait,
                   TxAnchor.freelock,
                   freelockwait,
                   lowlockwait,
                   TxAnchor.tlocksInUse,
                   jfs_tlocks_low,
                   list_empty(&TxAnchor.unlock_queue) ? "" : "not ");

      begin = offset;
      *start = buffer + begin;
      len -= begin;

      if (len > length)
            len = length;
      else
            *eof = 1;

      if (len < 0)
            len = 0;

      return len;
}
#endif

#if defined(CONFIG_PROC_FS) && defined(CONFIG_JFS_STATISTICS)
int jfs_txstats_read(char *buffer, char **start, off_t offset, int length,
                 int *eof, void *data)
{
      int len = 0;
      off_t begin;

      len += sprintf(buffer,
                   "JFS TxStats\n"
                   "===========\n"
                   "calls to txBegin = %d\n"
                   "txBegin blocked by sync barrier = %d\n"
                   "txBegin blocked by tlocks low = %d\n"
                   "txBegin blocked by no free tid = %d\n"
                   "calls to txBeginAnon = %d\n"
                   "txBeginAnon blocked by sync barrier = %d\n"
                   "txBeginAnon blocked by tlocks low = %d\n"
                   "calls to txLockAlloc = %d\n"
                   "tLockAlloc blocked by no free lock = %d\n",
                   TxStat.txBegin,
                   TxStat.txBegin_barrier,
                   TxStat.txBegin_lockslow,
                   TxStat.txBegin_freetid,
                   TxStat.txBeginAnon,
                   TxStat.txBeginAnon_barrier,
                   TxStat.txBeginAnon_lockslow,
                   TxStat.txLockAlloc,
                   TxStat.txLockAlloc_freelock);

      begin = offset;
      *start = buffer + begin;
      len -= begin;

      if (len > length)
            len = length;
      else
            *eof = 1;

      if (len < 0)
            len = 0;

      return len;
}
#endif

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