jfs_logmgr.c

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/*
 *   Copyright (C) International Business Machines Corp., 2000-2004
 *   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_logmgr.c: log manager
 *
 * for related information, see transaction manager (jfs_txnmgr.c), and
 * recovery manager (jfs_logredo.c).
 *
 * note: for detail, RTFS.
 *
 *  log buffer manager:
 * special purpose buffer manager supporting log i/o requirements.
 * per log serial pageout of logpage
 * queuing i/o requests and redrive i/o at iodone
 * maintain current logpage buffer
 * no caching since append only
 * appropriate jfs buffer cache buffers as needed
 *
 *  group commit:
 * transactions which wrote COMMIT records in the same in-memory
 * log page during the pageout of previous/current log page(s) are
 * committed together by the pageout of the page.
 *
 *  TBD lazy commit:
 * transactions are committed asynchronously when the log page
 * containing it COMMIT is paged out when it becomes full;
 *
 *  serialization:
 * . a per log lock serialize log write.
 * . a per log lock serialize group commit.
 * . a per log lock serialize log open/close;
 *
 *  TBD log integrity:
 * careful-write (ping-pong) of last logpage to recover from crash
 * in overwrite.
 * detection of split (out-of-order) write of physical sectors
 * of last logpage via timestamp at end of each sector
 * with its mirror data array at trailer).
 *
 *  alternatives:
 * lsn - 64-bit monotonically increasing integer vs
 * 32-bit lspn and page eor.
 */

#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/kthread.h>
#include <linux/buffer_head.h>      /* for sync_blockdev() */
#include <linux/bio.h>
#include <linux/freezer.h>
#include <linux/export.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include "jfs_incore.h"
#include "jfs_filsys.h"
#include "jfs_metapage.h"
#include "jfs_superblock.h"
#include "jfs_txnmgr.h"
#include "jfs_debug.h"


/*
 * lbuf's ready to be redriven.  Protected by log_redrive_lock (jfsIO thread)
 */
static struct lbuf *log_redrive_list;
static DEFINE_SPINLOCK(log_redrive_lock);


/*
 *  log read/write serialization (per log)
 */
#define LOG_LOCK_INIT(log)  mutex_init(&(log)->loglock)
#define LOG_LOCK(log)       mutex_lock(&((log)->loglock))
#define LOG_UNLOCK(log)     mutex_unlock(&((log)->loglock))


/*
 *  log group commit serialization (per log)
 */

#define LOGGC_LOCK_INIT(log)    spin_lock_init(&(log)->gclock)
#define LOGGC_LOCK(log)     spin_lock_irq(&(log)->gclock)
#define LOGGC_UNLOCK(log)   spin_unlock_irq(&(log)->gclock)
#define LOGGC_WAKEUP(tblk)  wake_up_all(&(tblk)->gcwait)

/*
 *  log sync serialization (per log)
 */
#define LOGSYNC_DELTA(logsize)      min((logsize)/8, 128*LOGPSIZE)
#define LOGSYNC_BARRIER(logsize)    ((logsize)/4)
/*
#define LOGSYNC_DELTA(logsize)      min((logsize)/4, 256*LOGPSIZE)
#define LOGSYNC_BARRIER(logsize)    ((logsize)/2)
*/


/*
 *  log buffer cache synchronization
 */
static DEFINE_SPINLOCK(jfsLCacheLock);

#define LCACHE_LOCK(flags)  spin_lock_irqsave(&jfsLCacheLock, flags)
#define LCACHE_UNLOCK(flags)    spin_unlock_irqrestore(&jfsLCacheLock, flags)

/*
 * See __SLEEP_COND in jfs_locks.h
 */
#define LCACHE_SLEEP_COND(wq, cond, flags)  \
do {                        \
    if (cond)               \
        break;              \
    __SLEEP_COND(wq, cond, LCACHE_LOCK(flags), LCACHE_UNLOCK(flags)); \
} while (0)

#define LCACHE_WAKEUP(event)    wake_up(event)


/*
 *  lbuf buffer cache (lCache) control
 */
/* log buffer manager pageout control (cumulative, inclusive) */
#define lbmREAD     0x0001
#define lbmWRITE    0x0002  /* enqueue at tail of write queue;
                 * init pageout if at head of queue;
                 */
#define lbmRELEASE  0x0004  /* remove from write queue
                 * at completion of pageout;
                 * do not free/recycle it yet:
                 * caller will free it;
                 */
#define lbmSYNC     0x0008  /* do not return to freelist
                 * when removed from write queue;
                 */
#define lbmFREE     0x0010  /* return to freelist
                 * at completion of pageout;
                 * the buffer may be recycled;
                 */
#define lbmDONE     0x0020
#define lbmERROR    0x0040
#define lbmGC       0x0080  /* lbmIODone to perform post-GC processing
                 * of log page
                 */
#define lbmDIRECT   0x0100

/*
 * Global list of active external journals
 */
static LIST_HEAD(jfs_external_logs);
static struct jfs_log *dummy_log = NULL;
static DEFINE_MUTEX(jfs_log_mutex);

/*
 * forward references
 */
static int lmWriteRecord(struct jfs_log * log, struct tblock * tblk,
             struct lrd * lrd, struct tlock * tlck);

static int lmNextPage(struct jfs_log * log);
static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
               int activate);

static int open_inline_log(struct super_block *sb);
static int open_dummy_log(struct super_block *sb);
static int lbmLogInit(struct jfs_log * log);
static void lbmLogShutdown(struct jfs_log * log);
static struct lbuf *lbmAllocate(struct jfs_log * log, int);
static void lbmFree(struct lbuf * bp);
static void lbmfree(struct lbuf * bp);
static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp);
static void lbmWrite(struct jfs_log * log, struct lbuf * bp, int flag, int cant_block);
static void lbmDirectWrite(struct jfs_log * log, struct lbuf * bp, int flag);
static int lbmIOWait(struct lbuf * bp, int flag);
static bio_end_io_t lbmIODone;
static void lbmStartIO(struct lbuf * bp);
static void lmGCwrite(struct jfs_log * log, int cant_block);
static int lmLogSync(struct jfs_log * log, int hard_sync);



/*
 *  statistics
 */
#ifdef CONFIG_JFS_STATISTICS
static struct lmStat {
    uint commit;        /* # of commit */
    uint pagedone;      /* # of page written */
    uint submitted;     /* # of pages submitted */
    uint full_page;     /* # of full pages submitted */
    uint partial_page;  /* # of partial pages submitted */
} lmStat;
#endif

static void write_special_inodes(struct jfs_log *log,
                 int (*writer)(struct address_space *))
{
    struct jfs_sb_info *sbi;

    list_for_each_entry(sbi, &log->sb_list, log_list) {
        writer(sbi->ipbmap->i_mapping);
        writer(sbi->ipimap->i_mapping);
        writer(sbi->direct_inode->i_mapping);
    }
}

/*
 * NAME:    lmLog()
 *
 * FUNCTION:    write a log record;
 *
 * PARAMETER:
 *
 * RETURN:  lsn - offset to the next log record to write (end-of-log);
 *      -1  - error;
 *
 * note: todo: log error handler
 */
int lmLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
      struct tlock * tlck)
{
    int lsn;
    int diffp, difft;
    struct metapage *mp = NULL;
    unsigned long flags;

    jfs_info("lmLog: log:0x%p tblk:0x%p, lrd:0x%p tlck:0x%p",
         log, tblk, lrd, tlck);

    LOG_LOCK(log);

    /* log by (out-of-transaction) JFS ? */
    if (tblk == NULL)
        goto writeRecord;

    /* log from page ? */
    if (tlck == NULL ||
        tlck->type & tlckBTROOT || (mp = tlck->mp) == NULL)
        goto writeRecord;

    /*
     *  initialize/update page/transaction recovery lsn
     */
    lsn = log->lsn;

    LOGSYNC_LOCK(log, flags);

    /*
     * initialize page lsn if first log write of the page
     */
    if (mp->lsn == 0) {
        mp->log = log;
        mp->lsn = lsn;
        log->count++;

        /* insert page at tail of logsynclist */
        list_add_tail(&mp->synclist, &log->synclist);
    }

    /*
     *  initialize/update lsn of tblock of the page
     *
     * transaction inherits oldest lsn of pages associated
     * with allocation/deallocation of resources (their
     * log records are used to reconstruct allocation map
     * at recovery time: inode for inode allocation map,
     * B+-tree index of extent descriptors for block
     * allocation map);
     * allocation map pages inherit transaction lsn at
     * commit time to allow forwarding log syncpt past log
     * records associated with allocation/deallocation of
     * resources only after persistent map of these map pages
     * have been updated and propagated to home.
     */
    /*
     * initialize transaction lsn:
     */
    if (tblk->lsn == 0) {
        /* inherit lsn of its first page logged */
        tblk->lsn = mp->lsn;
        log->count++;

        /* insert tblock after the page on logsynclist */
        list_add(&tblk->synclist, &mp->synclist);
    }
    /*
     * update transaction lsn:
     */
    else {
        /* inherit oldest/smallest lsn of page */
        logdiff(diffp, mp->lsn, log);
        logdiff(difft, tblk->lsn, log);
        if (diffp < difft) {
            /* update tblock lsn with page lsn */
            tblk->lsn = mp->lsn;

            /* move tblock after page on logsynclist */
            list_move(&tblk->synclist, &mp->synclist);
        }
    }

    LOGSYNC_UNLOCK(log, flags);

    /*
     *  write the log record
     */
      writeRecord:
    lsn = lmWriteRecord(log, tblk, lrd, tlck);

    /*
     * forward log syncpt if log reached next syncpt trigger
     */
    logdiff(diffp, lsn, log);
    if (diffp >= log->nextsync)
        lsn = lmLogSync(log, 0);

    /* update end-of-log lsn */
    log->lsn = lsn;

    LOG_UNLOCK(log);

    /* return end-of-log address */
    return lsn;
}

/*
 * NAME:    lmWriteRecord()
 *
 * FUNCTION:    move the log record to current log page
 *
 * PARAMETER:   cd  - commit descriptor
 *
 * RETURN:  end-of-log address
 *
 * serialization: LOG_LOCK() held on entry/exit
 */
static int
lmWriteRecord(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
          struct tlock * tlck)
{
    int lsn = 0;        /* end-of-log address */
    struct lbuf *bp;    /* dst log page buffer */
    struct logpage *lp; /* dst log page */
    caddr_t dst;        /* destination address in log page */
    int dstoffset;      /* end-of-log offset in log page */
    int freespace;      /* free space in log page */
    caddr_t p;      /* src meta-data page */
    caddr_t src;
    int srclen;
    int nbytes;     /* number of bytes to move */
    int i;
    int len;
    struct linelock *linelock;
    struct lv *lv;
    struct lvd *lvd;
    int l2linesize;

    len = 0;

    /* retrieve destination log page to write */
    bp = (struct lbuf *) log->bp;
    lp = (struct logpage *) bp->l_ldata;
    dstoffset = log->eor;

    /* any log data to write ? */
    if (tlck == NULL)
        goto moveLrd;

    /*
     *  move log record data
     */
    /* retrieve source meta-data page to log */
    if (tlck->flag & tlckPAGELOCK) {
        p = (caddr_t) (tlck->mp->data);
        linelock = (struct linelock *) & tlck->lock;
    }
    /* retrieve source in-memory inode to log */
    else if (tlck->flag & tlckINODELOCK) {
        if (tlck->type & tlckDTREE)
            p = (caddr_t) &JFS_IP(tlck->ip)->i_dtroot;
        else
            p = (caddr_t) &JFS_IP(tlck->ip)->i_xtroot;
        linelock = (struct linelock *) & tlck->lock;
    }
#ifdef  _JFS_WIP
    else if (tlck->flag & tlckINLINELOCK) {

        inlinelock = (struct inlinelock *) & tlck;
        p = (caddr_t) & inlinelock->pxd;
        linelock = (struct linelock *) & tlck;
    }
#endif              /* _JFS_WIP */
    else {
        jfs_err("lmWriteRecord: UFO tlck:0x%p", tlck);
        return 0;   /* Probably should trap */
    }
    l2linesize = linelock->l2linesize;

      moveData:
    ASSERT(linelock->index <= linelock->maxcnt);

    lv = linelock->lv;
    for (i = 0; i < linelock->index; i++, lv++) {
        if (lv->length == 0)
            continue;

        /* is page full ? */
        if (dstoffset >= LOGPSIZE - LOGPTLRSIZE) {
            /* page become full: move on to next page */
            lmNextPage(log);

            bp = log->bp;
            lp = (struct logpage *) bp->l_ldata;
            dstoffset = LOGPHDRSIZE;
        }

        /*
         * move log vector data
         */
        src = (u8 *) p + (lv->offset << l2linesize);
        srclen = lv->length << l2linesize;
        len += srclen;
        while (srclen > 0) {
            freespace = (LOGPSIZE - LOGPTLRSIZE) - dstoffset;
            nbytes = min(freespace, srclen);
            dst = (caddr_t) lp + dstoffset;
            memcpy(dst, src, nbytes);
            dstoffset += nbytes;

            /* is page not full ? */
            if (dstoffset < LOGPSIZE - LOGPTLRSIZE)
                break;

            /* page become full: move on to next page */
            lmNextPage(log);

            bp = (struct lbuf *) log->bp;
            lp = (struct logpage *) bp->l_ldata;
            dstoffset = LOGPHDRSIZE;

            srclen -= nbytes;
            src += nbytes;
        }

        /*
         * move log vector descriptor
         */
        len += 4;
        lvd = (struct lvd *) ((caddr_t) lp + dstoffset);
        lvd->offset = cpu_to_le16(lv->offset);
        lvd->length = cpu_to_le16(lv->length);
        dstoffset += 4;
        jfs_info("lmWriteRecord: lv offset:%d length:%d",
             lv->offset, lv->length);
    }

    if ((i = linelock->next)) {
        linelock = (struct linelock *) lid_to_tlock(i);
        goto moveData;
    }

    /*
     *  move log record descriptor
     */
      moveLrd:
    lrd->length = cpu_to_le16(len);

    src = (caddr_t) lrd;
    srclen = LOGRDSIZE;

    while (srclen > 0) {
        freespace = (LOGPSIZE - LOGPTLRSIZE) - dstoffset;
        nbytes = min(freespace, srclen);
        dst = (caddr_t) lp + dstoffset;
        memcpy(dst, src, nbytes);

        dstoffset += nbytes;
        srclen -= nbytes;

        /* are there more to move than freespace of page ? */
        if (srclen)
            goto pageFull;

        /*
         * end of log record descriptor
         */

        /* update last log record eor */
        log->eor = dstoffset;
        bp->l_eor = dstoffset;
        lsn = (log->page << L2LOGPSIZE) + dstoffset;

        if (lrd->type & cpu_to_le16(LOG_COMMIT)) {
            tblk->clsn = lsn;
            jfs_info("wr: tclsn:0x%x, beor:0x%x", tblk->clsn,
                 bp->l_eor);

            INCREMENT(lmStat.commit);   /* # of commit */

            /*
             * enqueue tblock for group commit:
             *
             * enqueue tblock of non-trivial/synchronous COMMIT
             * at tail of group commit queue
             * (trivial/asynchronous COMMITs are ignored by
             * group commit.)
             */
            LOGGC_LOCK(log);

            /* init tblock gc state */
            tblk->flag = tblkGC_QUEUE;
            tblk->bp = log->bp;
            tblk->pn = log->page;
            tblk->eor = log->eor;

            /* enqueue transaction to commit queue */
            list_add_tail(&tblk->cqueue, &log->cqueue);

            LOGGC_UNLOCK(log);
        }

        jfs_info("lmWriteRecord: lrd:0x%04x bp:0x%p pn:%d eor:0x%x",
            le16_to_cpu(lrd->type), log->bp, log->page, dstoffset);

        /* page not full ? */
        if (dstoffset < LOGPSIZE - LOGPTLRSIZE)
            return lsn;

          pageFull:
        /* page become full: move on to next page */
        lmNextPage(log);

        bp = (struct lbuf *) log->bp;
        lp = (struct logpage *) bp->l_ldata;
        dstoffset = LOGPHDRSIZE;
        src += nbytes;
    }

    return lsn;
}


/*
 * NAME:    lmNextPage()
 *
 * FUNCTION:    write current page and allocate next page.
 *
 * PARAMETER:   log
 *
 * RETURN:  0
 *
 * serialization: LOG_LOCK() held on entry/exit
 */
static int lmNextPage(struct jfs_log * log)
{
    struct logpage *lp;
    int lspn;       /* log sequence page number */
    int pn;         /* current page number */
    struct lbuf *bp;
    struct lbuf *nextbp;
    struct tblock *tblk;

    /* get current log page number and log sequence page number */
    pn = log->page;
    bp = log->bp;
    lp = (struct logpage *) bp->l_ldata;
    lspn = le32_to_cpu(lp->h.page);

    LOGGC_LOCK(log);

    /*
     *  write or queue the full page at the tail of write queue
     */
    /* get the tail tblk on commit queue */
    if (list_empty(&log->cqueue))
        tblk = NULL;
    else
        tblk = list_entry(log->cqueue.prev, struct tblock, cqueue);

    /* every tblk who has COMMIT record on the current page,
     * and has not been committed, must be on commit queue
     * since tblk is queued at commit queueu at the time
     * of writing its COMMIT record on the page before
     * page becomes full (even though the tblk thread
     * who wrote COMMIT record may have been suspended
     * currently);
     */

    /* is page bound with outstanding tail tblk ? */
    if (tblk && tblk->pn == pn) {
        /* mark tblk for end-of-page */
        tblk->flag |= tblkGC_EOP;

        if (log->cflag & logGC_PAGEOUT) {
            /* if page is not already on write queue,
             * just enqueue (no lbmWRITE to prevent redrive)
             * buffer to wqueue to ensure correct serial order
             * of the pages since log pages will be added
             * continuously
             */
            if (bp->l_wqnext == NULL)
                lbmWrite(log, bp, 0, 0);
        } else {
            /*
             * No current GC leader, initiate group commit
             */
            log->cflag |= logGC_PAGEOUT;
            lmGCwrite(log, 0);
        }
    }
    /* page is not bound with outstanding tblk:
     * init write or mark it to be redriven (lbmWRITE)
     */
    else {
        /* finalize the page */
        bp->l_ceor = bp->l_eor;
        lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
        lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmFREE, 0);
    }
    LOGGC_UNLOCK(log);

    /*
     *  allocate/initialize next page
     */
    /* if log wraps, the first data page of log is 2
     * (0 never used, 1 is superblock).
     */
    log->page = (pn == log->size - 1) ? 2 : pn + 1;
    log->eor = LOGPHDRSIZE; /* ? valid page empty/full at logRedo() */

    /* allocate/initialize next log page buffer */
    nextbp = lbmAllocate(log, log->page);
    nextbp->l_eor = log->eor;
    log->bp = nextbp;

    /* initialize next log page */
    lp = (struct logpage *) nextbp->l_ldata;
    lp->h.page = lp->t.page = cpu_to_le32(lspn + 1);
    lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE);

    return 0;
}


/*
 * NAME:    lmGroupCommit()
 *
 * FUNCTION:    group commit
 *  initiate pageout of the pages with COMMIT in the order of
 *  page number - redrive pageout of the page at the head of
 *  pageout queue until full page has been written.
 *
 * RETURN:
 *
 * NOTE:
 *  LOGGC_LOCK serializes log group commit queue, and
 *  transaction blocks on the commit queue.
 *  N.B. LOG_LOCK is NOT held during lmGroupCommit().
 */
int lmGroupCommit(struct jfs_log * log, struct tblock * tblk)
{
    int rc = 0;

    LOGGC_LOCK(log);

    /* group committed already ? */
    if (tblk->flag & tblkGC_COMMITTED) {
        if (tblk->flag & tblkGC_ERROR)
            rc = -EIO;

        LOGGC_UNLOCK(log);
        return rc;
    }
    jfs_info("lmGroup Commit: tblk = 0x%p, gcrtc = %d", tblk, log->gcrtc);

    if (tblk->xflag & COMMIT_LAZY)
        tblk->flag |= tblkGC_LAZY;

    if ((!(log->cflag & logGC_PAGEOUT)) && (!list_empty(&log->cqueue)) &&
        (!(tblk->xflag & COMMIT_LAZY) || test_bit(log_FLUSH, &log->flag)
         || jfs_tlocks_low)) {
        /*
         * No pageout in progress
         *
         * start group commit as its group leader.
         */
        log->cflag |= logGC_PAGEOUT;

        lmGCwrite(log, 0);
    }

    if (tblk->xflag & COMMIT_LAZY) {
        /*
         * Lazy transactions can leave now
         */
        LOGGC_UNLOCK(log);
        return 0;
    }

    /* lmGCwrite gives up LOGGC_LOCK, check again */

    if (tblk->flag & tblkGC_COMMITTED) {
        if (tblk->flag & tblkGC_ERROR)
            rc = -EIO;

        LOGGC_UNLOCK(log);
        return rc;
    }

    /* upcount transaction waiting for completion
     */
    log->gcrtc++;
    tblk->flag |= tblkGC_READY;

    __SLEEP_COND(tblk->gcwait, (tblk->flag & tblkGC_COMMITTED),
             LOGGC_LOCK(log), LOGGC_UNLOCK(log));

    /* removed from commit queue */
    if (tblk->flag & tblkGC_ERROR)
        rc = -EIO;

    LOGGC_UNLOCK(log);
    return rc;
}

/*
 * NAME:    lmGCwrite()
 *
 * FUNCTION:    group commit write
 *  initiate write of log page, building a group of all transactions
 *  with commit records on that page.
 *
 * RETURN:  None
 *
 * NOTE:
 *  LOGGC_LOCK must be held by caller.
 *  N.B. LOG_LOCK is NOT held during lmGroupCommit().
 */
static void lmGCwrite(struct jfs_log * log, int cant_write)
{
    struct lbuf *bp;
    struct logpage *lp;
    int gcpn;       /* group commit page number */
    struct tblock *tblk;
    struct tblock *xtblk = NULL;

    /*
     * build the commit group of a log page
     *
     * scan commit queue and make a commit group of all
     * transactions with COMMIT records on the same log page.
     */
    /* get the head tblk on the commit queue */
    gcpn = list_entry(log->cqueue.next, struct tblock, cqueue)->pn;

    list_for_each_entry(tblk, &log->cqueue, cqueue) {
        if (tblk->pn != gcpn)
            break;

        xtblk = tblk;

        /* state transition: (QUEUE, READY) -> COMMIT */
        tblk->flag |= tblkGC_COMMIT;
    }
    tblk = xtblk;       /* last tblk of the page */

    /*
     * pageout to commit transactions on the log page.
     */
    bp = (struct lbuf *) tblk->bp;
    lp = (struct logpage *) bp->l_ldata;
    /* is page already full ? */
    if (tblk->flag & tblkGC_EOP) {
        /* mark page to free at end of group commit of the page */
        tblk->flag &= ~tblkGC_EOP;
        tblk->flag |= tblkGC_FREE;
        bp->l_ceor = bp->l_eor;
        lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
        lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmGC,
             cant_write);
        INCREMENT(lmStat.full_page);
    }
    /* page is not yet full */
    else {
        bp->l_ceor = tblk->eor; /* ? bp->l_ceor = bp->l_eor; */
        lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
        lbmWrite(log, bp, lbmWRITE | lbmGC, cant_write);
        INCREMENT(lmStat.partial_page);
    }
}

/*
 * NAME:    lmPostGC()
 *
 * FUNCTION:    group commit post-processing
 *  Processes transactions after their commit records have been written
 *  to disk, redriving log I/O if necessary.
 *
 * RETURN:  None
 *
 * NOTE:
 *  This routine is called a interrupt time by lbmIODone
 */
static void lmPostGC(struct lbuf * bp)
{
    unsigned long flags;
    struct jfs_log *log = bp->l_log;
    struct logpage *lp;
    struct tblock *tblk, *temp;

    //LOGGC_LOCK(log);
    spin_lock_irqsave(&log->gclock, flags);
    /*
     * current pageout of group commit completed.
     *
     * remove/wakeup transactions from commit queue who were
     * group committed with the current log page
     */
    list_for_each_entry_safe(tblk, temp, &log->cqueue, cqueue) {
        if (!(tblk->flag & tblkGC_COMMIT))
            break;
        /* if transaction was marked GC_COMMIT then
         * it has been shipped in the current pageout
         * and made it to disk - it is committed.
         */

        if (bp->l_flag & lbmERROR)
            tblk->flag |= tblkGC_ERROR;

        /* remove it from the commit queue */
        list_del(&tblk->cqueue);
        tblk->flag &= ~tblkGC_QUEUE;

        if (tblk == log->flush_tblk) {
            /* we can stop flushing the log now */
            clear_bit(log_FLUSH, &log->flag);
            log->flush_tblk = NULL;
        }

        jfs_info("lmPostGC: tblk = 0x%p, flag = 0x%x", tblk,
             tblk->flag);

        if (!(tblk->xflag & COMMIT_FORCE))
            /*
             * Hand tblk over to lazy commit thread
             */
            txLazyUnlock(tblk);
        else {
            /* state transition: COMMIT -> COMMITTED */
            tblk->flag |= tblkGC_COMMITTED;

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

            LOGGC_WAKEUP(tblk);
        }

        /* was page full before pageout ?
         * (and this is the last tblk bound with the page)
         */
        if (tblk->flag & tblkGC_FREE)
            lbmFree(bp);
        /* did page become full after pageout ?
         * (and this is the last tblk bound with the page)
         */
        else if (tblk->flag & tblkGC_EOP) {
            /* finalize the page */
            lp = (struct logpage *) bp->l_ldata;
            bp->l_ceor = bp->l_eor;
            lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
            jfs_info("lmPostGC: calling lbmWrite");
            lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmFREE,
                 1);
        }

    }

    /* are there any transactions who have entered lnGroupCommit()
     * (whose COMMITs are after that of the last log page written.
     * They are waiting for new group commit (above at (SLEEP 1))
     * or lazy transactions are on a full (queued) log page,
     * select the latest ready transaction as new group leader and
     * wake her up to lead her group.
     */
    if ((!list_empty(&log->cqueue)) &&
        ((log->gcrtc > 0) || (tblk->bp->l_wqnext != NULL) ||
         test_bit(log_FLUSH, &log->flag) || jfs_tlocks_low))
        /*
         * Call lmGCwrite with new group leader
         */
        lmGCwrite(log, 1);

    /* no transaction are ready yet (transactions are only just
     * queued (GC_QUEUE) and not entered for group commit yet).
     * the first transaction entering group commit
     * will elect herself as new group leader.
     */
    else
        log->cflag &= ~logGC_PAGEOUT;

    //LOGGC_UNLOCK(log);
    spin_unlock_irqrestore(&log->gclock, flags);
    return;
}

/*
 * NAME:    lmLogSync()
 *
 * FUNCTION:    write log SYNCPT record for specified log
 *  if new sync address is available
 *  (normally the case if sync() is executed by back-ground
 *  process).
 *  calculate new value of i_nextsync which determines when
 *  this code is called again.
 *
 * PARAMETERS:  log - log structure
 *      hard_sync - 1 to force all metadata to be written
 *
 * RETURN:  0
 *
 * serialization: LOG_LOCK() held on entry/exit
 */
static int lmLogSync(struct jfs_log * log, int hard_sync)
{
    int logsize;
    int written;        /* written since last syncpt */
    int free;       /* free space left available */
    int delta;      /* additional delta to write normally */
    int more;       /* additional write granted */
    struct lrd lrd;
    int lsn;
    struct logsyncblk *lp;
    unsigned long flags;

    /* push dirty metapages out to disk */
    if (hard_sync)
        write_special_inodes(log, filemap_fdatawrite);
    else
        write_special_inodes(log, filemap_flush);

    /*
     *  forward syncpt
     */
    /* if last sync is same as last syncpt,
     * invoke sync point forward processing to update sync.
     */

    if (log->sync == log->syncpt) {
        LOGSYNC_LOCK(log, flags);
        if (list_empty(&log->synclist))
            log->sync = log->lsn;
        else {
            lp = list_entry(log->synclist.next,
                    struct logsyncblk, synclist);
            log->sync = lp->lsn;
        }
        LOGSYNC_UNLOCK(log, flags);

    }

    /* if sync is different from last syncpt,
     * write a SYNCPT record with syncpt = sync.
     * reset syncpt = sync
     */
    if (log->sync != log->syncpt) {
        lrd.logtid = 0;
        lrd.backchain = 0;
        lrd.type = cpu_to_le16(LOG_SYNCPT);
        lrd.length = 0;
        lrd.log.syncpt.sync = cpu_to_le32(log->sync);
        lsn = lmWriteRecord(log, NULL, &lrd, NULL);

        log->syncpt = log->sync;
    } else
        lsn = log->lsn;

    /*
     *  setup next syncpt trigger (SWAG)
     */
    logsize = log->logsize;

    logdiff(written, lsn, log);
    free = logsize - written;
    delta = LOGSYNC_DELTA(logsize);
    more = min(free / 2, delta);
    if (more < 2 * LOGPSIZE) {
        jfs_warn("\n ... Log Wrap ... Log Wrap ... Log Wrap ...\n");
        /*
         *  log wrapping
         *
         * option 1 - panic ? No.!
         * option 2 - shutdown file systems
         *        associated with log ?
         * option 3 - extend log ?
         * option 4 - second chance
         *
         * mark log wrapped, and continue.
         * when all active transactions are completed,
         * mark log valid for recovery.
         * if crashed during invalid state, log state
         * implies invalid log, forcing fsck().
         */
        /* mark log state log wrap in log superblock */
        /* log->state = LOGWRAP; */

        /* reset sync point computation */
        log->syncpt = log->sync = lsn;
        log->nextsync = delta;
    } else
        /* next syncpt trigger = written + more */
        log->nextsync = written + more;

    /* if number of bytes written from last sync point is more
     * than 1/4 of the log size, stop new transactions from
     * starting until all current transactions are completed
     * by setting syncbarrier flag.
     */
    if (!test_bit(log_SYNCBARRIER, &log->flag) &&
        (written > LOGSYNC_BARRIER(logsize)) && log->active) {
        set_bit(log_SYNCBARRIER, &log->flag);
        jfs_info("log barrier on: lsn=0x%x syncpt=0x%x", lsn,
             log->syncpt);
        /*
         * We may have to initiate group commit
         */
        jfs_flush_journal(log, 0);
    }

    return lsn;
}

/*
 * NAME:    jfs_syncpt
 *
 * FUNCTION:    write log SYNCPT record for specified log
 *
 * PARAMETERS:  log   - log structure
 *      hard_sync - set to 1 to force metadata to be written
 */
void jfs_syncpt(struct jfs_log *log, int hard_sync)
{   LOG_LOCK(log);
    lmLogSync(log, hard_sync);
    LOG_UNLOCK(log);
}

/*
 * NAME:    lmLogOpen()
 *
 * FUNCTION:    open the log on first open;
 *  insert filesystem in the active list of the log.
 *
 * PARAMETER:   ipmnt   - file system mount inode
 *      iplog   - log inode (out)
 *
 * RETURN:
 *
 * serialization:
 */
int lmLogOpen(struct super_block *sb)
{
    int rc;
    struct block_device *bdev;
    struct jfs_log *log;
    struct jfs_sb_info *sbi = JFS_SBI(sb);

    if (sbi->flag & JFS_NOINTEGRITY)
        return open_dummy_log(sb);

    if (sbi->mntflag & JFS_INLINELOG)
        return open_inline_log(sb);

    mutex_lock(&jfs_log_mutex);
    list_for_each_entry(log, &jfs_external_logs, journal_list) {
        if (log->bdev->bd_dev == sbi->logdev) {
            if (memcmp(log->uuid, sbi->loguuid,
                   sizeof(log->uuid))) {
                jfs_warn("wrong uuid on JFS journal\n");
                mutex_unlock(&jfs_log_mutex);
                return -EINVAL;
            }
            /*
             * add file system to log active file system list
             */
            if ((rc = lmLogFileSystem(log, sbi, 1))) {
                mutex_unlock(&jfs_log_mutex);
                return rc;
            }
            goto journal_found;
        }
    }

    if (!(log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL))) {
        mutex_unlock(&jfs_log_mutex);
        return -ENOMEM;
    }
    INIT_LIST_HEAD(&log->sb_list);
    init_waitqueue_head(&log->syncwait);

    /*
     *  external log as separate logical volume
     *
     * file systems to log may have n-to-1 relationship;
     */

    bdev = blkdev_get_by_dev(sbi->logdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
                 log);
    if (IS_ERR(bdev)) {
        rc = PTR_ERR(bdev);
        goto free;
    }

    log->bdev = bdev;
    memcpy(log->uuid, sbi->loguuid, sizeof(log->uuid));

    /*
     * initialize log:
     */
    if ((rc = lmLogInit(log)))
        goto close;

    list_add(&log->journal_list, &jfs_external_logs);

    /*
     * add file system to log active file system list
     */
    if ((rc = lmLogFileSystem(log, sbi, 1)))
        goto shutdown;

journal_found:
    LOG_LOCK(log);
    list_add(&sbi->log_list, &log->sb_list);
    sbi->log = log;
    LOG_UNLOCK(log);

    mutex_unlock(&jfs_log_mutex);
    return 0;

    /*
     *  unwind on error
     */
      shutdown:     /* unwind lbmLogInit() */
    list_del(&log->journal_list);
    lbmLogShutdown(log);

      close:        /* close external log device */
    blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);

      free:     /* free log descriptor */
    mutex_unlock(&jfs_log_mutex);
    kfree(log);

    jfs_warn("lmLogOpen: exit(%d)", rc);
    return rc;
}

static int open_inline_log(struct super_block *sb)
{
    struct jfs_log *log;
    int rc;

    if (!(log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL)))
        return -ENOMEM;
    INIT_LIST_HEAD(&log->sb_list);
    init_waitqueue_head(&log->syncwait);

    set_bit(log_INLINELOG, &log->flag);
    log->bdev = sb->s_bdev;
    log->base = addressPXD(&JFS_SBI(sb)->logpxd);
    log->size = lengthPXD(&JFS_SBI(sb)->logpxd) >>
        (L2LOGPSIZE - sb->s_blocksize_bits);
    log->l2bsize = sb->s_blocksize_bits;
    ASSERT(L2LOGPSIZE >= sb->s_blocksize_bits);

    /*
     * initialize log.
     */
    if ((rc = lmLogInit(log))) {
        kfree(log);
        jfs_warn("lmLogOpen: exit(%d)", rc);
        return rc;
    }

    list_add(&JFS_SBI(sb)->log_list, &log->sb_list);
    JFS_SBI(sb)->log = log;

    return rc;
}

static int open_dummy_log(struct super_block *sb)
{
    int rc;

    mutex_lock(&jfs_log_mutex);
    if (!dummy_log) {
        dummy_log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL);
        if (!dummy_log) {
            mutex_unlock(&jfs_log_mutex);
            return -ENOMEM;
        }
        INIT_LIST_HEAD(&dummy_log->sb_list);
        init_waitqueue_head(&dummy_log->syncwait);
        dummy_log->no_integrity = 1;
        /* Make up some stuff */
        dummy_log->base = 0;
        dummy_log->size = 1024;
        rc = lmLogInit(dummy_log);
        if (rc) {
            kfree(dummy_log);
            dummy_log = NULL;
            mutex_unlock(&jfs_log_mutex);
            return rc;
        }
    }

    LOG_LOCK(dummy_log);
    list_add(&JFS_SBI(sb)->log_list, &dummy_log->sb_list);
    JFS_SBI(sb)->log = dummy_log;
    LOG_UNLOCK(dummy_log);
    mutex_unlock(&jfs_log_mutex);

    return 0;
}

/*
 * NAME:    lmLogInit()
 *
 * FUNCTION:    log initialization at first log open.
 *
 *  logredo() (or logformat()) should have been run previously.
 *  initialize the log from log superblock.
 *  set the log state in the superblock to LOGMOUNT and
 *  write SYNCPT log record.
 *
 * PARAMETER:   log - log structure
 *
 * RETURN:  0   - if ok
 *      -EINVAL - bad log magic number or superblock dirty
 *      error returned from logwait()
 *
 * serialization: single first open thread
 */
int lmLogInit(struct jfs_log * log)
{
    int rc = 0;
    struct lrd lrd;
    struct logsuper *logsuper;
    struct lbuf *bpsuper;
    struct lbuf *bp;
    struct logpage *lp;
    int lsn = 0;

    jfs_info("lmLogInit: log:0x%p", log);

    /* initialize the group commit serialization lock */
    LOGGC_LOCK_INIT(log);

    /* allocate/initialize the log write serialization lock */
    LOG_LOCK_INIT(log);

    LOGSYNC_LOCK_INIT(log);

    INIT_LIST_HEAD(&log->synclist);

    INIT_LIST_HEAD(&log->cqueue);
    log->flush_tblk = NULL;

    log->count = 0;

    /*
     * initialize log i/o
     */
    if ((rc = lbmLogInit(log)))
        return rc;

    if (!test_bit(log_INLINELOG, &log->flag))
        log->l2bsize = L2LOGPSIZE;

    /* check for disabled journaling to disk */
    if (log->no_integrity) {
        /*
         * Journal pages will still be filled.  When the time comes
         * to actually do the I/O, the write is not done, and the
         * endio routine is called directly.
         */
        bp = lbmAllocate(log , 0);
        log->bp = bp;
        bp->l_pn = bp->l_eor = 0;
    } else {
        /*
         * validate log superblock
         */
        if ((rc = lbmRead(log, 1, &bpsuper)))
            goto errout10;

        logsuper = (struct logsuper *) bpsuper->l_ldata;

        if (logsuper->magic != cpu_to_le32(LOGMAGIC)) {
            jfs_warn("*** Log Format Error ! ***");
            rc = -EINVAL;
            goto errout20;
        }

        /* logredo() should have been run successfully. */
        if (logsuper->state != cpu_to_le32(LOGREDONE)) {
            jfs_warn("*** Log Is Dirty ! ***");
            rc = -EINVAL;
            goto errout20;
        }

        /* initialize log from log superblock */
        if (test_bit(log_INLINELOG,&log->flag)) {
            if (log->size != le32_to_cpu(logsuper->size)) {
                rc = -EINVAL;
                goto errout20;
            }
            jfs_info("lmLogInit: inline log:0x%p base:0x%Lx "
                 "size:0x%x", log,
                 (unsigned long long) log->base, log->size);
        } else {
            if (memcmp(logsuper->uuid, log->uuid, 16)) {
                jfs_warn("wrong uuid on JFS log device");
                goto errout20;
            }
            log->size = le32_to_cpu(logsuper->size);
            log->l2bsize = le32_to_cpu(logsuper->l2bsize);
            jfs_info("lmLogInit: external log:0x%p base:0x%Lx "
                 "size:0x%x", log,
                 (unsigned long long) log->base, log->size);
        }

        log->page = le32_to_cpu(logsuper->end) / LOGPSIZE;
        log->eor = le32_to_cpu(logsuper->end) - (LOGPSIZE * log->page);

        /*
         * initialize for log append write mode
         */
        /* establish current/end-of-log page/buffer */
        if ((rc = lbmRead(log, log->page, &bp)))
            goto errout20;

        lp = (struct logpage *) bp->l_ldata;

        jfs_info("lmLogInit: lsn:0x%x page:%d eor:%d:%d",
             le32_to_cpu(logsuper->end), log->page, log->eor,
             le16_to_cpu(lp->h.eor));

        log->bp = bp;
        bp->l_pn = log->page;
        bp->l_eor = log->eor;

        /* if current page is full, move on to next page */
        if (log->eor >= LOGPSIZE - LOGPTLRSIZE)
            lmNextPage(log);

        /*
         * initialize log syncpoint
         */
        /*
         * write the first SYNCPT record with syncpoint = 0
         * (i.e., log redo up to HERE !);
         * remove current page from lbm write queue at end of pageout
         * (to write log superblock update), but do not release to
         * freelist;
         */
        lrd.logtid = 0;
        lrd.backchain = 0;
        lrd.type = cpu_to_le16(LOG_SYNCPT);
        lrd.length = 0;
        lrd.log.syncpt.sync = 0;
        lsn = lmWriteRecord(log, NULL, &lrd, NULL);
        bp = log->bp;
        bp->l_ceor = bp->l_eor;
        lp = (struct logpage *) bp->l_ldata;
        lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
        lbmWrite(log, bp, lbmWRITE | lbmSYNC, 0);
        if ((rc = lbmIOWait(bp, 0)))
            goto errout30;

        /*
         * update/write superblock
         */
        logsuper->state = cpu_to_le32(LOGMOUNT);
        log->serial = le32_to_cpu(logsuper->serial) + 1;
        logsuper->serial = cpu_to_le32(log->serial);
        lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
        if ((rc = lbmIOWait(bpsuper, lbmFREE)))
            goto errout30;
    }

    /* initialize logsync parameters */
    log->logsize = (log->size - 2) << L2LOGPSIZE;
    log->lsn = lsn;
    log->syncpt = lsn;
    log->sync = log->syncpt;
    log->nextsync = LOGSYNC_DELTA(log->logsize);

    jfs_info("lmLogInit: lsn:0x%x syncpt:0x%x sync:0x%x",
         log->lsn, log->syncpt, log->sync);

    /*
     * initialize for lazy/group commit
     */
    log->clsn = lsn;

    return 0;

    /*
     *  unwind on error
     */
      errout30:     /* release log page */
    log->wqueue = NULL;
    bp->l_wqnext = NULL;
    lbmFree(bp);

      errout20:     /* release log superblock */
    lbmFree(bpsuper);

      errout10:     /* unwind lbmLogInit() */
    lbmLogShutdown(log);

    jfs_warn("lmLogInit: exit(%d)", rc);
    return rc;
}


/*
 * NAME:    lmLogClose()
 *
 * FUNCTION:    remove file system <ipmnt> from active list of log <iplog>
 *      and close it on last close.
 *
 * PARAMETER:   sb  - superblock
 *
 * RETURN:  errors from subroutines
 *
 * serialization:
 */
int lmLogClose(struct super_block *sb)
{
    struct jfs_sb_info *sbi = JFS_SBI(sb);
    struct jfs_log *log = sbi->log;
    struct block_device *bdev;
    int rc = 0;

    jfs_info("lmLogClose: log:0x%p", log);

    mutex_lock(&jfs_log_mutex);
    LOG_LOCK(log);
    list_del(&sbi->log_list);
    LOG_UNLOCK(log);
    sbi->log = NULL;

    /*
     * We need to make sure all of the "written" metapages
     * actually make it to disk
     */
    sync_blockdev(sb->s_bdev);

    if (test_bit(log_INLINELOG, &log->flag)) {
        /*
         *  in-line log in host file system
         */
        rc = lmLogShutdown(log);
        kfree(log);
        goto out;
    }

    if (!log->no_integrity)
        lmLogFileSystem(log, sbi, 0);

    if (!list_empty(&log->sb_list))
        goto out;

    /*
     * TODO: ensure that the dummy_log is in a state to allow
     * lbmLogShutdown to deallocate all the buffers and call
     * kfree against dummy_log.  For now, leave dummy_log & its
     * buffers in memory, and resuse if another no-integrity mount
     * is requested.
     */
    if (log->no_integrity)
        goto out;

    /*
     *  external log as separate logical volume
     */
    list_del(&log->journal_list);
    bdev = log->bdev;
    rc = lmLogShutdown(log);

    blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);

    kfree(log);

      out:
    mutex_unlock(&jfs_log_mutex);
    jfs_info("lmLogClose: exit(%d)", rc);
    return rc;
}


/*
 * NAME:    jfs_flush_journal()
 *
 * FUNCTION:    initiate write of any outstanding transactions to the journal
 *      and optionally wait until they are all written to disk
 *
 *      wait == 0  flush until latest txn is committed, don't wait
 *      wait == 1  flush until latest txn is committed, wait
 *      wait > 1   flush until all txn's are complete, wait
 */
void jfs_flush_journal(struct jfs_log *log, int wait)
{
    int i;
    struct tblock *target = NULL;

    /* jfs_write_inode may call us during read-only mount */
    if (!log)
        return;

    jfs_info("jfs_flush_journal: log:0x%p wait=%d", log, wait);

    LOGGC_LOCK(log);

    if (!list_empty(&log->cqueue)) {
        /*
         * This ensures that we will keep writing to the journal as long
         * as there are unwritten commit records
         */
        target = list_entry(log->cqueue.prev, struct tblock, cqueue);

        if (test_bit(log_FLUSH, &log->flag)) {
            /*
             * We're already flushing.
             * if flush_tblk is NULL, we are flushing everything,
             * so leave it that way.  Otherwise, update it to the
             * latest transaction
             */
            if (log->flush_tblk)
                log->flush_tblk = target;
        } else {
            /* Only flush until latest transaction is committed */
            log->flush_tblk = target;
            set_bit(log_FLUSH, &log->flag);

            /*
             * Initiate I/O on outstanding transactions
             */
            if (!(log->cflag & logGC_PAGEOUT)) {
                log->cflag |= logGC_PAGEOUT;
                lmGCwrite(log, 0);
            }
        }
    }
    if ((wait > 1) || test_bit(log_SYNCBARRIER, &log->flag)) {
        /* Flush until all activity complete */
        set_bit(log_FLUSH, &log->flag);
        log->flush_tblk = NULL;
    }

    if (wait && target && !(target->flag & tblkGC_COMMITTED)) {
        DECLARE_WAITQUEUE(__wait, current);

        add_wait_queue(&target->gcwait, &__wait);
        set_current_state(TASK_UNINTERRUPTIBLE);
        LOGGC_UNLOCK(log);
        schedule();
        __set_current_state(TASK_RUNNING);
        LOGGC_LOCK(log);
        remove_wait_queue(&target->gcwait, &__wait);
    }
    LOGGC_UNLOCK(log);

    if (wait < 2)
        return;

    write_special_inodes(log, filemap_fdatawrite);

    /*
     * If there was recent activity, we may need to wait
     * for the lazycommit thread to catch up
     */
    if ((!list_empty(&log->cqueue)) || !list_empty(&log->synclist)) {
        for (i = 0; i < 200; i++) { /* Too much? */
            msleep(250);
            write_special_inodes(log, filemap_fdatawrite);
            if (list_empty(&log->cqueue) &&
                list_empty(&log->synclist))
                break;
        }
    }
    assert(list_empty(&log->cqueue));

#ifdef CONFIG_JFS_DEBUG
    if (!list_empty(&log->synclist)) {
        struct logsyncblk *lp;

        printk(KERN_ERR "jfs_flush_journal: synclist not empty\n");
        list_for_each_entry(lp, &log->synclist, synclist) {
            if (lp->xflag & COMMIT_PAGE) {
                struct metapage *mp = (struct metapage *)lp;
                print_hex_dump(KERN_ERR, "metapage: ",
                           DUMP_PREFIX_ADDRESS, 16, 4,
                           mp, sizeof(struct metapage), 0);
                print_hex_dump(KERN_ERR, "page: ",
                           DUMP_PREFIX_ADDRESS, 16,
                           sizeof(long), mp->page,
                           sizeof(struct page), 0);
            } else
                print_hex_dump(KERN_ERR, "tblock:",
                           DUMP_PREFIX_ADDRESS, 16, 4,
                           lp, sizeof(struct tblock), 0);
        }
    }
#else
    WARN_ON(!list_empty(&log->synclist));
#endif
    clear_bit(log_FLUSH, &log->flag);
}

/*
 * NAME:    lmLogShutdown()
 *
 * FUNCTION:    log shutdown at last LogClose().
 *
 *      write log syncpt record.
 *      update super block to set redone flag to 0.
 *
 * PARAMETER:   log - log inode
 *
 * RETURN:  0   - success
 *
 * serialization: single last close thread
 */
int lmLogShutdown(struct jfs_log * log)
{
    int rc;
    struct lrd lrd;
    int lsn;
    struct logsuper *logsuper;
    struct lbuf *bpsuper;
    struct lbuf *bp;
    struct logpage *lp;

    jfs_info("lmLogShutdown: log:0x%p", log);

    jfs_flush_journal(log, 2);

    /*
     * write the last SYNCPT record with syncpoint = 0
     * (i.e., log redo up to HERE !)
     */
    lrd.logtid = 0;
    lrd.backchain = 0;
    lrd.type = cpu_to_le16(LOG_SYNCPT);
    lrd.length = 0;
    lrd.log.syncpt.sync = 0;

    lsn = lmWriteRecord(log, NULL, &lrd, NULL);
    bp = log->bp;
    lp = (struct logpage *) bp->l_ldata;
    lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
    lbmWrite(log, log->bp, lbmWRITE | lbmRELEASE | lbmSYNC, 0);
    lbmIOWait(log->bp, lbmFREE);
    log->bp = NULL;

    /*
     * synchronous update log superblock
     * mark log state as shutdown cleanly
     * (i.e., Log does not need to be replayed).
     */
    if ((rc = lbmRead(log, 1, &bpsuper)))
        goto out;

    logsuper = (struct logsuper *) bpsuper->l_ldata;
    logsuper->state = cpu_to_le32(LOGREDONE);
    logsuper->end = cpu_to_le32(lsn);
    lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
    rc = lbmIOWait(bpsuper, lbmFREE);

    jfs_info("lmLogShutdown: lsn:0x%x page:%d eor:%d",
         lsn, log->page, log->eor);

      out:
    /*
     * shutdown per log i/o
     */
    lbmLogShutdown(log);

    if (rc) {
        jfs_warn("lmLogShutdown: exit(%d)", rc);
    }
    return rc;
}


/*
 * NAME:    lmLogFileSystem()
 *
 * FUNCTION:    insert (<activate> = true)/remove (<activate> = false)
 *  file system into/from log active file system list.
 *
 * PARAMETE:    log - pointer to logs inode.
 *      fsdev   - kdev_t of filesystem.
 *      serial  - pointer to returned log serial number
 *      activate - insert/remove device from active list.
 *
 * RETURN:  0   - success
 *      errors returned by vms_iowait().
 */
static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
               int activate)
{
    int rc = 0;
    int i;
    struct logsuper *logsuper;
    struct lbuf *bpsuper;
    char *uuid = sbi->uuid;

    /*
     * insert/remove file system device to log active file system list.
     */
    if ((rc = lbmRead(log, 1, &bpsuper)))
        return rc;

    logsuper = (struct logsuper *) bpsuper->l_ldata;
    if (activate) {
        for (i = 0; i < MAX_ACTIVE; i++)
            if (!memcmp(logsuper->active[i].uuid, NULL_UUID, 16)) {
                memcpy(logsuper->active[i].uuid, uuid, 16);
                sbi->aggregate = i;
                break;
            }
        if (i == MAX_ACTIVE) {
            jfs_warn("Too many file systems sharing journal!");
            lbmFree(bpsuper);
            return -EMFILE; /* Is there a better rc? */
        }
    } else {
        for (i = 0; i < MAX_ACTIVE; i++)
            if (!memcmp(logsuper->active[i].uuid, uuid, 16)) {
                memcpy(logsuper->active[i].uuid, NULL_UUID, 16);
                break;
            }
        if (i == MAX_ACTIVE) {
            jfs_warn("Somebody stomped on the journal!");
            lbmFree(bpsuper);
            return -EIO;
        }

    }

    /*
     * synchronous write log superblock:
     *
     * write sidestream bypassing write queue:
     * at file system mount, log super block is updated for
     * activation of the file system before any log record
     * (MOUNT record) of the file system, and at file system
     * unmount, all meta data for the file system has been
     * flushed before log super block is updated for deactivation
     * of the file system.
     */
    lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
    rc = lbmIOWait(bpsuper, lbmFREE);

    return rc;
}

/*
 *      log buffer manager (lbm)
 *      ------------------------
 *
 * special purpose buffer manager supporting log i/o requirements.
 *
 * per log write queue:
 * log pageout occurs in serial order by fifo write queue and
 * restricting to a single i/o in pregress at any one time.
 * a circular singly-linked list
 * (log->wrqueue points to the tail, and buffers are linked via
 * bp->wrqueue field), and
 * maintains log page in pageout ot waiting for pageout in serial pageout.
 */

/*
 *  lbmLogInit()
 *
 * initialize per log I/O setup at lmLogInit()
 */
static int lbmLogInit(struct jfs_log * log)
{               /* log inode */
    int i;
    struct lbuf *lbuf;

    jfs_info("lbmLogInit: log:0x%p", log);

    /* initialize current buffer cursor */
    log->bp = NULL;

    /* initialize log device write queue */
    log->wqueue = NULL;

    /*
     * Each log has its own buffer pages allocated to it.  These are
     * not managed by the page cache.  This ensures that a transaction
     * writing to the log does not block trying to allocate a page from
     * the page cache (for the log).  This would be bad, since page
     * allocation waits on the kswapd thread that may be committing inodes
     * which would cause log activity.  Was that clear?  I'm trying to
     * avoid deadlock here.
     */
    init_waitqueue_head(&log->free_wait);

    log->lbuf_free = NULL;

    for (i = 0; i < LOGPAGES;) {
        char *buffer;
        uint offset;
        struct page *page;

        buffer = (char *) get_zeroed_page(GFP_KERNEL);
        if (buffer == NULL)
            goto error;
        page = virt_to_page(buffer);
        for (offset = 0; offset < PAGE_SIZE; offset += LOGPSIZE) {
            lbuf = kmalloc(sizeof(struct lbuf), GFP_KERNEL);
            if (lbuf == NULL) {
                if (offset == 0)
                    free_page((unsigned long) buffer);
                goto error;
            }
            if (offset) /* we already have one reference */
                get_page(page);
            lbuf->l_offset = offset;
            lbuf->l_ldata = buffer + offset;
            lbuf->l_page = page;
            lbuf->l_log = log;
            init_waitqueue_head(&lbuf->l_ioevent);

            lbuf->l_freelist = log->lbuf_free;
            log->lbuf_free = lbuf;
            i++;
        }
    }

    return (0);

      error:
    lbmLogShutdown(log);
    return -ENOMEM;
}


/*
 *  lbmLogShutdown()
 *
 * finalize per log I/O setup at lmLogShutdown()
 */
static void lbmLogShutdown(struct jfs_log * log)
{
    struct lbuf *lbuf;

    jfs_info("lbmLogShutdown: log:0x%p", log);

    lbuf = log->lbuf_free;
    while (lbuf) {
        struct lbuf *next = lbuf->l_freelist;
        __free_page(lbuf->l_page);
        kfree(lbuf);
        lbuf = next;
    }
}


/*
 *  lbmAllocate()
 *
 * allocate an empty log buffer
 */
static struct lbuf *lbmAllocate(struct jfs_log * log, int pn)
{
    struct lbuf *bp;
    unsigned long flags;

    /*
     * recycle from log buffer freelist if any
     */
    LCACHE_LOCK(flags);
    LCACHE_SLEEP_COND(log->free_wait, (bp = log->lbuf_free), flags);
    log->lbuf_free = bp->l_freelist;
    LCACHE_UNLOCK(flags);

    bp->l_flag = 0;

    bp->l_wqnext = NULL;
    bp->l_freelist = NULL;

    bp->l_pn = pn;
    bp->l_blkno = log->base + (pn << (L2LOGPSIZE - log->l2bsize));
    bp->l_ceor = 0;

    return bp;
}


/*
 *  lbmFree()
 *
 * release a log buffer to freelist
 */
static void lbmFree(struct lbuf * bp)
{
    unsigned long flags;

    LCACHE_LOCK(flags);

    lbmfree(bp);

    LCACHE_UNLOCK(flags);
}

static void lbmfree(struct lbuf * bp)
{
    struct jfs_log *log = bp->l_log;

    assert(bp->l_wqnext == NULL);

    /*
     * return the buffer to head of freelist
     */
    bp->l_freelist = log->lbuf_free;
    log->lbuf_free = bp;

    wake_up(&log->free_wait);
    return;
}


/*
 * NAME:    lbmRedrive
 *
 * FUNCTION:    add a log buffer to the log redrive list
 *
 * PARAMETER:
 *  bp  - log buffer
 *
 * NOTES:
 *  Takes log_redrive_lock.
 */
static inline void lbmRedrive(struct lbuf *bp)
{
    unsigned long flags;

    spin_lock_irqsave(&log_redrive_lock, flags);
    bp->l_redrive_next = log_redrive_list;
    log_redrive_list = bp;
    spin_unlock_irqrestore(&log_redrive_lock, flags);

    wake_up_process(jfsIOthread);
}


/*
 *  lbmRead()
 */
static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
{
    struct bio *bio;
    struct lbuf *bp;

    /*
     * allocate a log buffer
     */
    *bpp = bp = lbmAllocate(log, pn);
    jfs_info("lbmRead: bp:0x%p pn:0x%x", bp, pn);

    bp->l_flag |= lbmREAD;

    bio = bio_alloc(GFP_NOFS, 1);

    bio->bi_sector = bp->l_blkno << (log->l2bsize - 9);
    bio->bi_bdev = log->bdev;
    bio->bi_io_vec[0].bv_page = bp->l_page;
    bio->bi_io_vec[0].bv_len = LOGPSIZE;
    bio->bi_io_vec[0].bv_offset = bp->l_offset;

    bio->bi_vcnt = 1;
    bio->bi_idx = 0;
    bio->bi_size = LOGPSIZE;

    bio->bi_end_io = lbmIODone;
    bio->bi_private = bp;
    submit_bio(READ_SYNC, bio);

    wait_event(bp->l_ioevent, (bp->l_flag != lbmREAD));

    return 0;
}


/*
 *  lbmWrite()
 *
 * buffer at head of pageout queue stays after completion of
 * partial-page pageout and redriven by explicit initiation of
 * pageout by caller until full-page pageout is completed and
 * released.
 *
 * device driver i/o done redrives pageout of new buffer at
 * head of pageout queue when current buffer at head of pageout
 * queue is released at the completion of its full-page pageout.
 *
 * LOGGC_LOCK() serializes lbmWrite() by lmNextPage() and lmGroupCommit().
 * LCACHE_LOCK() serializes xflag between lbmWrite() and lbmIODone()
 */
static void lbmWrite(struct jfs_log * log, struct lbuf * bp, int flag,
             int cant_block)
{
    struct lbuf *tail;
    unsigned long flags;

    jfs_info("lbmWrite: bp:0x%p flag:0x%x pn:0x%x", bp, flag, bp->l_pn);

    /* map the logical block address to physical block address */
    bp->l_blkno =
        log->base + (bp->l_pn << (L2LOGPSIZE - log->l2bsize));

    LCACHE_LOCK(flags);     /* disable+lock */

    /*
     * initialize buffer for device driver
     */
    bp->l_flag = flag;

    /*
     *  insert bp at tail of write queue associated with log
     *
     * (request is either for bp already/currently at head of queue
     * or new bp to be inserted at tail)
     */
    tail = log->wqueue;

    /* is buffer not already on write queue ? */
    if (bp->l_wqnext == NULL) {
        /* insert at tail of wqueue */
        if (tail == NULL) {
            log->wqueue = bp;
            bp->l_wqnext = bp;
        } else {
            log->wqueue = bp;
            bp->l_wqnext = tail->l_wqnext;
            tail->l_wqnext = bp;
        }

        tail = bp;
    }

    /* is buffer at head of wqueue and for write ? */
    if ((bp != tail->l_wqnext) || !(flag & lbmWRITE)) {
        LCACHE_UNLOCK(flags);   /* unlock+enable */
        return;
    }

    LCACHE_UNLOCK(flags);   /* unlock+enable */

    if (cant_block)
        lbmRedrive(bp);
    else if (flag & lbmSYNC)
        lbmStartIO(bp);
    else {
        LOGGC_UNLOCK(log);
        lbmStartIO(bp);
        LOGGC_LOCK(log);
    }
}


/*
 *  lbmDirectWrite()
 *
 * initiate pageout bypassing write queue for sidestream
 * (e.g., log superblock) write;
 */
static void lbmDirectWrite(struct jfs_log * log, struct lbuf * bp, int flag)
{
    jfs_info("lbmDirectWrite: bp:0x%p flag:0x%x pn:0x%x",
         bp, flag, bp->l_pn);

    /*
     * initialize buffer for device driver
     */
    bp->l_flag = flag | lbmDIRECT;

    /* map the logical block address to physical block address */
    bp->l_blkno =
        log->base + (bp->l_pn << (L2LOGPSIZE - log->l2bsize));

    /*
     *  initiate pageout of the page
     */
    lbmStartIO(bp);
}


/*
 * NAME:    lbmStartIO()
 *
 * FUNCTION:    Interface to DD strategy routine
 *
 * RETURN:  none
 *
 * serialization: LCACHE_LOCK() is NOT held during log i/o;
 */
static void lbmStartIO(struct lbuf * bp)
{
    struct bio *bio;
    struct jfs_log *log = bp->l_log;

    jfs_info("lbmStartIO\n");

    bio = bio_alloc(GFP_NOFS, 1);
    bio->bi_sector = bp->l_blkno << (log->l2bsize - 9);
    bio->bi_bdev = log->bdev;
    bio->bi_io_vec[0].bv_page = bp->l_page;
    bio->bi_io_vec[0].bv_len = LOGPSIZE;
    bio->bi_io_vec[0].bv_offset = bp->l_offset;

    bio->bi_vcnt = 1;
    bio->bi_idx = 0;
    bio->bi_size = LOGPSIZE;

    bio->bi_end_io = lbmIODone;
    bio->bi_private = bp;

    /* check if journaling to disk has been disabled */
    if (log->no_integrity) {
        bio->bi_size = 0;
        lbmIODone(bio, 0);
    } else {
        submit_bio(WRITE_SYNC, bio);
        INCREMENT(lmStat.submitted);
    }
}


/*
 *  lbmIOWait()
 */
static int lbmIOWait(struct lbuf * bp, int flag)
{
    unsigned long flags;
    int rc = 0;

    jfs_info("lbmIOWait1: bp:0x%p flag:0x%x:0x%x", bp, bp->l_flag, flag);

    LCACHE_LOCK(flags);     /* disable+lock */

    LCACHE_SLEEP_COND(bp->l_ioevent, (bp->l_flag & lbmDONE), flags);

    rc = (bp->l_flag & lbmERROR) ? -EIO : 0;

    if (flag & lbmFREE)
        lbmfree(bp);

    LCACHE_UNLOCK(flags);   /* unlock+enable */

    jfs_info("lbmIOWait2: bp:0x%p flag:0x%x:0x%x", bp, bp->l_flag, flag);
    return rc;
}

/*
 *  lbmIODone()
 *
 * executed at INTIODONE level
 */
static void lbmIODone(struct bio *bio, int error)
{
    struct lbuf *bp = bio->bi_private;
    struct lbuf *nextbp, *tail;
    struct jfs_log *log;
    unsigned long flags;

    /*
     * get back jfs buffer bound to the i/o buffer
     */
    jfs_info("lbmIODone: bp:0x%p flag:0x%x", bp, bp->l_flag);

    LCACHE_LOCK(flags);     /* disable+lock */

    bp->l_flag |= lbmDONE;

    if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
        bp->l_flag |= lbmERROR;

        jfs_err("lbmIODone: I/O error in JFS log");
    }

    bio_put(bio);

    /*
     *  pagein completion
     */
    if (bp->l_flag & lbmREAD) {
        bp->l_flag &= ~lbmREAD;

        LCACHE_UNLOCK(flags);   /* unlock+enable */

        /* wakeup I/O initiator */
        LCACHE_WAKEUP(&bp->l_ioevent);

        return;
    }

    /*
     *  pageout completion
     *
     * the bp at the head of write queue has completed pageout.
     *
     * if single-commit/full-page pageout, remove the current buffer
     * from head of pageout queue, and redrive pageout with
     * the new buffer at head of pageout queue;
     * otherwise, the partial-page pageout buffer stays at
     * the head of pageout queue to be redriven for pageout
     * by lmGroupCommit() until full-page pageout is completed.
     */
    bp->l_flag &= ~lbmWRITE;
    INCREMENT(lmStat.pagedone);

    /* update committed lsn */
    log = bp->l_log;
    log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor;

    if (bp->l_flag & lbmDIRECT) {
        LCACHE_WAKEUP(&bp->l_ioevent);
        LCACHE_UNLOCK(flags);
        return;
    }

    tail = log->wqueue;

    /* single element queue */
    if (bp == tail) {
        /* remove head buffer of full-page pageout
         * from log device write queue
         */
        if (bp->l_flag & lbmRELEASE) {
            log->wqueue = NULL;
            bp->l_wqnext = NULL;
        }
    }
    /* multi element queue */
    else {
        /* remove head buffer of full-page pageout
         * from log device write queue
         */
        if (bp->l_flag & lbmRELEASE) {
            nextbp = tail->l_wqnext = bp->l_wqnext;
            bp->l_wqnext = NULL;

            /*
             * redrive pageout of next page at head of write queue:
             * redrive next page without any bound tblk
             * (i.e., page w/o any COMMIT records), or
             * first page of new group commit which has been
             * queued after current page (subsequent pageout
             * is performed synchronously, except page without
             * any COMMITs) by lmGroupCommit() as indicated
             * by lbmWRITE flag;
             */
            if (nextbp->l_flag & lbmWRITE) {
                /*
                 * We can't do the I/O at interrupt time.
                 * The jfsIO thread can do it
                 */
                lbmRedrive(nextbp);
            }
        }
    }

    /*
     *  synchronous pageout:
     *
     * buffer has not necessarily been removed from write queue
     * (e.g., synchronous write of partial-page with COMMIT):
     * leave buffer for i/o initiator to dispose
     */
    if (bp->l_flag & lbmSYNC) {
        LCACHE_UNLOCK(flags);   /* unlock+enable */

        /* wakeup I/O initiator */
        LCACHE_WAKEUP(&bp->l_ioevent);
    }

    /*
     *  Group Commit pageout:
     */
    else if (bp->l_flag & lbmGC) {
        LCACHE_UNLOCK(flags);
        lmPostGC(bp);
    }

    /*
     *  asynchronous pageout:
     *
     * buffer must have been removed from write queue:
     * insert buffer at head of freelist where it can be recycled
     */
    else {
        assert(bp->l_flag & lbmRELEASE);
        assert(bp->l_flag & lbmFREE);
        lbmfree(bp);

        LCACHE_UNLOCK(flags);   /* unlock+enable */
    }
}

int jfsIOWait(void *arg)
{
    struct lbuf *bp;

    do {
        spin_lock_irq(&log_redrive_lock);
        while ((bp = log_redrive_list)) {
            log_redrive_list = bp->l_redrive_next;
            bp->l_redrive_next = NULL;
            spin_unlock_irq(&log_redrive_lock);
            lbmStartIO(bp);
            spin_lock_irq(&log_redrive_lock);
        }

        if (freezing(current)) {
            spin_unlock_irq(&log_redrive_lock);
            try_to_freeze();
        } else {
            set_current_state(TASK_INTERRUPTIBLE);
            spin_unlock_irq(&log_redrive_lock);
            schedule();
            __set_current_state(TASK_RUNNING);
        }
    } while (!kthread_should_stop());

    jfs_info("jfsIOWait being killed!");
    return 0;
}

/*
 * NAME:    lmLogFormat()/jfs_logform()
 *
 * FUNCTION:    format file system log
 *
 * PARAMETERS:
 *  log - volume log
 *  logAddress - start address of log space in FS block
 *  logSize - length of log space in FS block;
 *
 * RETURN:  0   - success
 *      -EIO    - i/o error
 *
 * XXX: We're synchronously writing one page at a time.  This needs to
 *  be improved by writing multiple pages at once.
 */
int lmLogFormat(struct jfs_log *log, s64 logAddress, int logSize)
{
    int rc = -EIO;
    struct jfs_sb_info *sbi;
    struct logsuper *logsuper;
    struct logpage *lp;
    int lspn;       /* log sequence page number */
    struct lrd *lrd_ptr;
    int npages = 0;
    struct lbuf *bp;

    jfs_info("lmLogFormat: logAddress:%Ld logSize:%d",
         (long long)logAddress, logSize);

    sbi = list_entry(log->sb_list.next, struct jfs_sb_info, log_list);

    /* allocate a log buffer */
    bp = lbmAllocate(log, 1);

    npages = logSize >> sbi->l2nbperpage;

    /*
     *  log space:
     *
     * page 0 - reserved;
     * page 1 - log superblock;
     * page 2 - log data page: A SYNC log record is written
     *      into this page at logform time;
     * pages 3-N - log data page: set to empty log data pages;
     */
    /*
     *  init log superblock: log page 1
     */
    logsuper = (struct logsuper *) bp->l_ldata;

    logsuper->magic = cpu_to_le32(LOGMAGIC);
    logsuper->version = cpu_to_le32(LOGVERSION);
    logsuper->state = cpu_to_le32(LOGREDONE);
    logsuper->flag = cpu_to_le32(sbi->mntflag); /* ? */
    logsuper->size = cpu_to_le32(npages);
    logsuper->bsize = cpu_to_le32(sbi->bsize);
    logsuper->l2bsize = cpu_to_le32(sbi->l2bsize);
    logsuper->end = cpu_to_le32(2 * LOGPSIZE + LOGPHDRSIZE + LOGRDSIZE);

    bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
    bp->l_blkno = logAddress + sbi->nbperpage;
    lbmStartIO(bp);
    if ((rc = lbmIOWait(bp, 0)))
        goto exit;

    /*
     *  init pages 2 to npages-1 as log data pages:
     *
     * log page sequence number (lpsn) initialization:
     *
     * pn:   0     1     2     3                 n-1
     *       +-----+-----+=====+=====+===.....===+=====+
     * lspn:             N-1   0     1           N-2
     *                   <--- N page circular file ---->
     *
     * the N (= npages-2) data pages of the log is maintained as
     * a circular file for the log records;
     * lpsn grows by 1 monotonically as each log page is written
     * to the circular file of the log;
     * and setLogpage() will not reset the page number even if
     * the eor is equal to LOGPHDRSIZE. In order for binary search
     * still work in find log end process, we have to simulate the
     * log wrap situation at the log format time.
     * The 1st log page written will have the highest lpsn. Then
     * the succeeding log pages will have ascending order of
     * the lspn starting from 0, ... (N-2)
     */
    lp = (struct logpage *) bp->l_ldata;
    /*
     * initialize 1st log page to be written: lpsn = N - 1,
     * write a SYNCPT log record is written to this page
     */
    lp->h.page = lp->t.page = cpu_to_le32(npages - 3);
    lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE + LOGRDSIZE);

    lrd_ptr = (struct lrd *) &lp->data;
    lrd_ptr->logtid = 0;
    lrd_ptr->backchain = 0;
    lrd_ptr->type = cpu_to_le16(LOG_SYNCPT);
    lrd_ptr->length = 0;
    lrd_ptr->log.syncpt.sync = 0;

    bp->l_blkno += sbi->nbperpage;
    bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
    lbmStartIO(bp);
    if ((rc = lbmIOWait(bp, 0)))
        goto exit;

    /*
     *  initialize succeeding log pages: lpsn = 0, 1, ..., (N-2)
     */
    for (lspn = 0; lspn < npages - 3; lspn++) {
        lp->h.page = lp->t.page = cpu_to_le32(lspn);
        lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE);

        bp->l_blkno += sbi->nbperpage;
        bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
        lbmStartIO(bp);
        if ((rc = lbmIOWait(bp, 0)))
            goto exit;
    }

    rc = 0;
exit:
    /*
     *  finalize log
     */
    /* release the buffer */
    lbmFree(bp);

    return rc;
}

#ifdef CONFIG_JFS_STATISTICS
static int jfs_lmstats_proc_show(struct seq_file *m, void *v)
{
    seq_printf(m,
               "JFS Logmgr stats\n"
               "================\n"
               "commits = %d\n"
               "writes submitted = %d\n"
               "writes completed = %d\n"
               "full pages submitted = %d\n"
               "partial pages submitted = %d\n",
               lmStat.commit,
               lmStat.submitted,
               lmStat.pagedone,
               lmStat.full_page,
               lmStat.partial_page);
    return 0;
}

static int jfs_lmstats_proc_open(struct inode *inode, struct file *file)
{
    return single_open(file, jfs_lmstats_proc_show, NULL);
}

const struct file_operations jfs_lmstats_proc_fops = {
    .owner      = THIS_MODULE,
    .open       = jfs_lmstats_proc_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};
#endif /* CONFIG_JFS_STATISTICS */