ClabureDB: Classified Bug-Reports Database

   /*
    *   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/delay.h>
  #include <linux/mutex.h>
  #include <linux/seq_file.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 vaild for recovery.
                 * if crashed during invalid state, log state
                 * implies invald 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 = open_by_devnum(sbi->logdev, FMODE_READ|FMODE_WRITE);
        if (IS_ERR(bdev)) {
                rc = -PTR_ERR(bdev);
                goto free;
        }

        if ((rc = bd_claim(bdev, log))) {
                goto close;
        }

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

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

        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);

      unclaim:
        bd_release(bdev);

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

      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);

        bd_release(bdev);
        blkdev_put(bdev, FMODE_READ|FMODE_WRITE);

        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);
                        refrigerator();
                } 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 */