jfs_txnmgr.c

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/*
 *   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/completion.h>
#include <linux/freezer.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kthread.h>
#include <linux/seq_file.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();
    io_schedule();
    __set_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 = 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 = 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 committing 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) {
        printk(KERN_ERR "txLock: trying to lock locked page!");
        print_hex_dump(KERN_ERR, "ip: ", DUMP_PREFIX_ADDRESS, 16, 4,
                   ip, sizeof(*ip), 0);
        print_hex_dump(KERN_ERR, "mp: ", DUMP_PREFIX_ADDRESS, 16, 4,
                   mp, sizeof(*mp), 0);
        print_hex_dump(KERN_ERR, "Locker's tblock: ",
                   DUMP_PREFIX_ADDRESS, 16, 4, tid_to_tblock(tid),
                   sizeof(struct tblock), 0);
        print_hex_dump(KERN_ERR, "Tlock: ", DUMP_PREFIX_ADDRESS, 16, 4,
                   tlck, sizeof(*tlck), 0);
        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;
    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) {
        ihold(tblk->u.ip);
        /*
         * 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)
         */
        /*
         * I believe this code is no longer needed.  Splitting I_LOCK
         * into two bits, I_NEW and I_SYNC should prevent this
         * deadlock as well.  But since I don't have a JFS testload
         * to verify this, only a trivial s/I_LOCK/I_SYNC/ was done.
         * Joern
         */
        if (tblk->u.ip->i_state & I_SYNC)
            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;
    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) {
        /* This odd declaration suppresses a bogus gcc warning */
        pxd_t pxd = 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) {
            /* 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);
            try_to_freeze();
        } else {
            DECLARE_WAITQUEUE(wq, current);

            add_wait_queue(&jfs_commit_thread_wait, &wq);
            set_current_state(TASK_INTERRUPTIBLE);
            LAZY_UNLOCK(flags);
            schedule();
            __set_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;
    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);
                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.
                 */

                /* Move from anon_list to anon_list2 */
                list_move(&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();
            try_to_freeze();
        } else {
            set_current_state(TASK_INTERRUPTIBLE);
            TXN_UNLOCK();
            schedule();
            __set_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)
static int jfs_txanchor_proc_show(struct seq_file *m, void *v)
{
    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";

    seq_printf(m,
               "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 ");
    return 0;
}

static int jfs_txanchor_proc_open(struct inode *inode, struct file *file)
{
    return single_open(file, jfs_txanchor_proc_show, NULL);
}

const struct file_operations jfs_txanchor_proc_fops = {
    .owner      = THIS_MODULE,
    .open       = jfs_txanchor_proc_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};
#endif

#if defined(CONFIG_PROC_FS) && defined(CONFIG_JFS_STATISTICS)
static int jfs_txstats_proc_show(struct seq_file *m, void *v)
{
    seq_printf(m,
               "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);
    return 0;
}

static int jfs_txstats_proc_open(struct inode *inode, struct file *file)
{
    return single_open(file, jfs_txstats_proc_show, NULL);
}

const struct file_operations jfs_txstats_proc_fops = {
    .owner      = THIS_MODULE,
    .open       = jfs_txstats_proc_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};
#endif