xref: /openbmc/linux/fs/jfs/jfs_logmgr.c (revision 615c36f5)
1 /*
2  *   Copyright (C) International Business Machines Corp., 2000-2004
3  *   Portions Copyright (C) Christoph Hellwig, 2001-2002
4  *
5  *   This program is free software;  you can redistribute it and/or modify
6  *   it under the terms of the GNU General Public License as published by
7  *   the Free Software Foundation; either version 2 of the License, or
8  *   (at your option) any later version.
9  *
10  *   This program is distributed in the hope that it will be useful,
11  *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
13  *   the GNU General Public License for more details.
14  *
15  *   You should have received a copy of the GNU General Public License
16  *   along with this program;  if not, write to the Free Software
17  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  */
19 
20 /*
21  *	jfs_logmgr.c: log manager
22  *
23  * for related information, see transaction manager (jfs_txnmgr.c), and
24  * recovery manager (jfs_logredo.c).
25  *
26  * note: for detail, RTFS.
27  *
28  *	log buffer manager:
29  * special purpose buffer manager supporting log i/o requirements.
30  * per log serial pageout of logpage
31  * queuing i/o requests and redrive i/o at iodone
32  * maintain current logpage buffer
33  * no caching since append only
34  * appropriate jfs buffer cache buffers as needed
35  *
36  *	group commit:
37  * transactions which wrote COMMIT records in the same in-memory
38  * log page during the pageout of previous/current log page(s) are
39  * committed together by the pageout of the page.
40  *
41  *	TBD lazy commit:
42  * transactions are committed asynchronously when the log page
43  * containing it COMMIT is paged out when it becomes full;
44  *
45  *	serialization:
46  * . a per log lock serialize log write.
47  * . a per log lock serialize group commit.
48  * . a per log lock serialize log open/close;
49  *
50  *	TBD log integrity:
51  * careful-write (ping-pong) of last logpage to recover from crash
52  * in overwrite.
53  * detection of split (out-of-order) write of physical sectors
54  * of last logpage via timestamp at end of each sector
55  * with its mirror data array at trailer).
56  *
57  *	alternatives:
58  * lsn - 64-bit monotonically increasing integer vs
59  * 32-bit lspn and page eor.
60  */
61 
62 #include <linux/fs.h>
63 #include <linux/blkdev.h>
64 #include <linux/interrupt.h>
65 #include <linux/completion.h>
66 #include <linux/kthread.h>
67 #include <linux/buffer_head.h>		/* for sync_blockdev() */
68 #include <linux/bio.h>
69 #include <linux/freezer.h>
70 #include <linux/export.h>
71 #include <linux/delay.h>
72 #include <linux/mutex.h>
73 #include <linux/seq_file.h>
74 #include <linux/slab.h>
75 #include "jfs_incore.h"
76 #include "jfs_filsys.h"
77 #include "jfs_metapage.h"
78 #include "jfs_superblock.h"
79 #include "jfs_txnmgr.h"
80 #include "jfs_debug.h"
81 
82 
83 /*
84  * lbuf's ready to be redriven.  Protected by log_redrive_lock (jfsIO thread)
85  */
86 static struct lbuf *log_redrive_list;
87 static DEFINE_SPINLOCK(log_redrive_lock);
88 
89 
90 /*
91  *	log read/write serialization (per log)
92  */
93 #define LOG_LOCK_INIT(log)	mutex_init(&(log)->loglock)
94 #define LOG_LOCK(log)		mutex_lock(&((log)->loglock))
95 #define LOG_UNLOCK(log)		mutex_unlock(&((log)->loglock))
96 
97 
98 /*
99  *	log group commit serialization (per log)
100  */
101 
102 #define LOGGC_LOCK_INIT(log)	spin_lock_init(&(log)->gclock)
103 #define LOGGC_LOCK(log)		spin_lock_irq(&(log)->gclock)
104 #define LOGGC_UNLOCK(log)	spin_unlock_irq(&(log)->gclock)
105 #define LOGGC_WAKEUP(tblk)	wake_up_all(&(tblk)->gcwait)
106 
107 /*
108  *	log sync serialization (per log)
109  */
110 #define	LOGSYNC_DELTA(logsize)		min((logsize)/8, 128*LOGPSIZE)
111 #define	LOGSYNC_BARRIER(logsize)	((logsize)/4)
112 /*
113 #define	LOGSYNC_DELTA(logsize)		min((logsize)/4, 256*LOGPSIZE)
114 #define	LOGSYNC_BARRIER(logsize)	((logsize)/2)
115 */
116 
117 
118 /*
119  *	log buffer cache synchronization
120  */
121 static DEFINE_SPINLOCK(jfsLCacheLock);
122 
123 #define	LCACHE_LOCK(flags)	spin_lock_irqsave(&jfsLCacheLock, flags)
124 #define	LCACHE_UNLOCK(flags)	spin_unlock_irqrestore(&jfsLCacheLock, flags)
125 
126 /*
127  * See __SLEEP_COND in jfs_locks.h
128  */
129 #define LCACHE_SLEEP_COND(wq, cond, flags)	\
130 do {						\
131 	if (cond)				\
132 		break;				\
133 	__SLEEP_COND(wq, cond, LCACHE_LOCK(flags), LCACHE_UNLOCK(flags)); \
134 } while (0)
135 
136 #define	LCACHE_WAKEUP(event)	wake_up(event)
137 
138 
139 /*
140  *	lbuf buffer cache (lCache) control
141  */
142 /* log buffer manager pageout control (cumulative, inclusive) */
143 #define	lbmREAD		0x0001
144 #define	lbmWRITE	0x0002	/* enqueue at tail of write queue;
145 				 * init pageout if at head of queue;
146 				 */
147 #define	lbmRELEASE	0x0004	/* remove from write queue
148 				 * at completion of pageout;
149 				 * do not free/recycle it yet:
150 				 * caller will free it;
151 				 */
152 #define	lbmSYNC		0x0008	/* do not return to freelist
153 				 * when removed from write queue;
154 				 */
155 #define lbmFREE		0x0010	/* return to freelist
156 				 * at completion of pageout;
157 				 * the buffer may be recycled;
158 				 */
159 #define	lbmDONE		0x0020
160 #define	lbmERROR	0x0040
161 #define lbmGC		0x0080	/* lbmIODone to perform post-GC processing
162 				 * of log page
163 				 */
164 #define lbmDIRECT	0x0100
165 
166 /*
167  * Global list of active external journals
168  */
169 static LIST_HEAD(jfs_external_logs);
170 static struct jfs_log *dummy_log = NULL;
171 static DEFINE_MUTEX(jfs_log_mutex);
172 
173 /*
174  * forward references
175  */
176 static int lmWriteRecord(struct jfs_log * log, struct tblock * tblk,
177 			 struct lrd * lrd, struct tlock * tlck);
178 
179 static int lmNextPage(struct jfs_log * log);
180 static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
181 			   int activate);
182 
183 static int open_inline_log(struct super_block *sb);
184 static int open_dummy_log(struct super_block *sb);
185 static int lbmLogInit(struct jfs_log * log);
186 static void lbmLogShutdown(struct jfs_log * log);
187 static struct lbuf *lbmAllocate(struct jfs_log * log, int);
188 static void lbmFree(struct lbuf * bp);
189 static void lbmfree(struct lbuf * bp);
190 static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp);
191 static void lbmWrite(struct jfs_log * log, struct lbuf * bp, int flag, int cant_block);
192 static void lbmDirectWrite(struct jfs_log * log, struct lbuf * bp, int flag);
193 static int lbmIOWait(struct lbuf * bp, int flag);
194 static bio_end_io_t lbmIODone;
195 static void lbmStartIO(struct lbuf * bp);
196 static void lmGCwrite(struct jfs_log * log, int cant_block);
197 static int lmLogSync(struct jfs_log * log, int hard_sync);
198 
199 
200 
201 /*
202  *	statistics
203  */
204 #ifdef CONFIG_JFS_STATISTICS
205 static struct lmStat {
206 	uint commit;		/* # of commit */
207 	uint pagedone;		/* # of page written */
208 	uint submitted;		/* # of pages submitted */
209 	uint full_page;		/* # of full pages submitted */
210 	uint partial_page;	/* # of partial pages submitted */
211 } lmStat;
212 #endif
213 
214 static void write_special_inodes(struct jfs_log *log,
215 				 int (*writer)(struct address_space *))
216 {
217 	struct jfs_sb_info *sbi;
218 
219 	list_for_each_entry(sbi, &log->sb_list, log_list) {
220 		writer(sbi->ipbmap->i_mapping);
221 		writer(sbi->ipimap->i_mapping);
222 		writer(sbi->direct_inode->i_mapping);
223 	}
224 }
225 
226 /*
227  * NAME:	lmLog()
228  *
229  * FUNCTION:	write a log record;
230  *
231  * PARAMETER:
232  *
233  * RETURN:	lsn - offset to the next log record to write (end-of-log);
234  *		-1  - error;
235  *
236  * note: todo: log error handler
237  */
238 int lmLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
239 	  struct tlock * tlck)
240 {
241 	int lsn;
242 	int diffp, difft;
243 	struct metapage *mp = NULL;
244 	unsigned long flags;
245 
246 	jfs_info("lmLog: log:0x%p tblk:0x%p, lrd:0x%p tlck:0x%p",
247 		 log, tblk, lrd, tlck);
248 
249 	LOG_LOCK(log);
250 
251 	/* log by (out-of-transaction) JFS ? */
252 	if (tblk == NULL)
253 		goto writeRecord;
254 
255 	/* log from page ? */
256 	if (tlck == NULL ||
257 	    tlck->type & tlckBTROOT || (mp = tlck->mp) == NULL)
258 		goto writeRecord;
259 
260 	/*
261 	 *	initialize/update page/transaction recovery lsn
262 	 */
263 	lsn = log->lsn;
264 
265 	LOGSYNC_LOCK(log, flags);
266 
267 	/*
268 	 * initialize page lsn if first log write of the page
269 	 */
270 	if (mp->lsn == 0) {
271 		mp->log = log;
272 		mp->lsn = lsn;
273 		log->count++;
274 
275 		/* insert page at tail of logsynclist */
276 		list_add_tail(&mp->synclist, &log->synclist);
277 	}
278 
279 	/*
280 	 *	initialize/update lsn of tblock of the page
281 	 *
282 	 * transaction inherits oldest lsn of pages associated
283 	 * with allocation/deallocation of resources (their
284 	 * log records are used to reconstruct allocation map
285 	 * at recovery time: inode for inode allocation map,
286 	 * B+-tree index of extent descriptors for block
287 	 * allocation map);
288 	 * allocation map pages inherit transaction lsn at
289 	 * commit time to allow forwarding log syncpt past log
290 	 * records associated with allocation/deallocation of
291 	 * resources only after persistent map of these map pages
292 	 * have been updated and propagated to home.
293 	 */
294 	/*
295 	 * initialize transaction lsn:
296 	 */
297 	if (tblk->lsn == 0) {
298 		/* inherit lsn of its first page logged */
299 		tblk->lsn = mp->lsn;
300 		log->count++;
301 
302 		/* insert tblock after the page on logsynclist */
303 		list_add(&tblk->synclist, &mp->synclist);
304 	}
305 	/*
306 	 * update transaction lsn:
307 	 */
308 	else {
309 		/* inherit oldest/smallest lsn of page */
310 		logdiff(diffp, mp->lsn, log);
311 		logdiff(difft, tblk->lsn, log);
312 		if (diffp < difft) {
313 			/* update tblock lsn with page lsn */
314 			tblk->lsn = mp->lsn;
315 
316 			/* move tblock after page on logsynclist */
317 			list_move(&tblk->synclist, &mp->synclist);
318 		}
319 	}
320 
321 	LOGSYNC_UNLOCK(log, flags);
322 
323 	/*
324 	 *	write the log record
325 	 */
326       writeRecord:
327 	lsn = lmWriteRecord(log, tblk, lrd, tlck);
328 
329 	/*
330 	 * forward log syncpt if log reached next syncpt trigger
331 	 */
332 	logdiff(diffp, lsn, log);
333 	if (diffp >= log->nextsync)
334 		lsn = lmLogSync(log, 0);
335 
336 	/* update end-of-log lsn */
337 	log->lsn = lsn;
338 
339 	LOG_UNLOCK(log);
340 
341 	/* return end-of-log address */
342 	return lsn;
343 }
344 
345 /*
346  * NAME:	lmWriteRecord()
347  *
348  * FUNCTION:	move the log record to current log page
349  *
350  * PARAMETER:	cd	- commit descriptor
351  *
352  * RETURN:	end-of-log address
353  *
354  * serialization: LOG_LOCK() held on entry/exit
355  */
356 static int
357 lmWriteRecord(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
358 	      struct tlock * tlck)
359 {
360 	int lsn = 0;		/* end-of-log address */
361 	struct lbuf *bp;	/* dst log page buffer */
362 	struct logpage *lp;	/* dst log page */
363 	caddr_t dst;		/* destination address in log page */
364 	int dstoffset;		/* end-of-log offset in log page */
365 	int freespace;		/* free space in log page */
366 	caddr_t p;		/* src meta-data page */
367 	caddr_t src;
368 	int srclen;
369 	int nbytes;		/* number of bytes to move */
370 	int i;
371 	int len;
372 	struct linelock *linelock;
373 	struct lv *lv;
374 	struct lvd *lvd;
375 	int l2linesize;
376 
377 	len = 0;
378 
379 	/* retrieve destination log page to write */
380 	bp = (struct lbuf *) log->bp;
381 	lp = (struct logpage *) bp->l_ldata;
382 	dstoffset = log->eor;
383 
384 	/* any log data to write ? */
385 	if (tlck == NULL)
386 		goto moveLrd;
387 
388 	/*
389 	 *	move log record data
390 	 */
391 	/* retrieve source meta-data page to log */
392 	if (tlck->flag & tlckPAGELOCK) {
393 		p = (caddr_t) (tlck->mp->data);
394 		linelock = (struct linelock *) & tlck->lock;
395 	}
396 	/* retrieve source in-memory inode to log */
397 	else if (tlck->flag & tlckINODELOCK) {
398 		if (tlck->type & tlckDTREE)
399 			p = (caddr_t) &JFS_IP(tlck->ip)->i_dtroot;
400 		else
401 			p = (caddr_t) &JFS_IP(tlck->ip)->i_xtroot;
402 		linelock = (struct linelock *) & tlck->lock;
403 	}
404 #ifdef	_JFS_WIP
405 	else if (tlck->flag & tlckINLINELOCK) {
406 
407 		inlinelock = (struct inlinelock *) & tlck;
408 		p = (caddr_t) & inlinelock->pxd;
409 		linelock = (struct linelock *) & tlck;
410 	}
411 #endif				/* _JFS_WIP */
412 	else {
413 		jfs_err("lmWriteRecord: UFO tlck:0x%p", tlck);
414 		return 0;	/* Probably should trap */
415 	}
416 	l2linesize = linelock->l2linesize;
417 
418       moveData:
419 	ASSERT(linelock->index <= linelock->maxcnt);
420 
421 	lv = linelock->lv;
422 	for (i = 0; i < linelock->index; i++, lv++) {
423 		if (lv->length == 0)
424 			continue;
425 
426 		/* is page full ? */
427 		if (dstoffset >= LOGPSIZE - LOGPTLRSIZE) {
428 			/* page become full: move on to next page */
429 			lmNextPage(log);
430 
431 			bp = log->bp;
432 			lp = (struct logpage *) bp->l_ldata;
433 			dstoffset = LOGPHDRSIZE;
434 		}
435 
436 		/*
437 		 * move log vector data
438 		 */
439 		src = (u8 *) p + (lv->offset << l2linesize);
440 		srclen = lv->length << l2linesize;
441 		len += srclen;
442 		while (srclen > 0) {
443 			freespace = (LOGPSIZE - LOGPTLRSIZE) - dstoffset;
444 			nbytes = min(freespace, srclen);
445 			dst = (caddr_t) lp + dstoffset;
446 			memcpy(dst, src, nbytes);
447 			dstoffset += nbytes;
448 
449 			/* is page not full ? */
450 			if (dstoffset < LOGPSIZE - LOGPTLRSIZE)
451 				break;
452 
453 			/* page become full: move on to next page */
454 			lmNextPage(log);
455 
456 			bp = (struct lbuf *) log->bp;
457 			lp = (struct logpage *) bp->l_ldata;
458 			dstoffset = LOGPHDRSIZE;
459 
460 			srclen -= nbytes;
461 			src += nbytes;
462 		}
463 
464 		/*
465 		 * move log vector descriptor
466 		 */
467 		len += 4;
468 		lvd = (struct lvd *) ((caddr_t) lp + dstoffset);
469 		lvd->offset = cpu_to_le16(lv->offset);
470 		lvd->length = cpu_to_le16(lv->length);
471 		dstoffset += 4;
472 		jfs_info("lmWriteRecord: lv offset:%d length:%d",
473 			 lv->offset, lv->length);
474 	}
475 
476 	if ((i = linelock->next)) {
477 		linelock = (struct linelock *) lid_to_tlock(i);
478 		goto moveData;
479 	}
480 
481 	/*
482 	 *	move log record descriptor
483 	 */
484       moveLrd:
485 	lrd->length = cpu_to_le16(len);
486 
487 	src = (caddr_t) lrd;
488 	srclen = LOGRDSIZE;
489 
490 	while (srclen > 0) {
491 		freespace = (LOGPSIZE - LOGPTLRSIZE) - dstoffset;
492 		nbytes = min(freespace, srclen);
493 		dst = (caddr_t) lp + dstoffset;
494 		memcpy(dst, src, nbytes);
495 
496 		dstoffset += nbytes;
497 		srclen -= nbytes;
498 
499 		/* are there more to move than freespace of page ? */
500 		if (srclen)
501 			goto pageFull;
502 
503 		/*
504 		 * end of log record descriptor
505 		 */
506 
507 		/* update last log record eor */
508 		log->eor = dstoffset;
509 		bp->l_eor = dstoffset;
510 		lsn = (log->page << L2LOGPSIZE) + dstoffset;
511 
512 		if (lrd->type & cpu_to_le16(LOG_COMMIT)) {
513 			tblk->clsn = lsn;
514 			jfs_info("wr: tclsn:0x%x, beor:0x%x", tblk->clsn,
515 				 bp->l_eor);
516 
517 			INCREMENT(lmStat.commit);	/* # of commit */
518 
519 			/*
520 			 * enqueue tblock for group commit:
521 			 *
522 			 * enqueue tblock of non-trivial/synchronous COMMIT
523 			 * at tail of group commit queue
524 			 * (trivial/asynchronous COMMITs are ignored by
525 			 * group commit.)
526 			 */
527 			LOGGC_LOCK(log);
528 
529 			/* init tblock gc state */
530 			tblk->flag = tblkGC_QUEUE;
531 			tblk->bp = log->bp;
532 			tblk->pn = log->page;
533 			tblk->eor = log->eor;
534 
535 			/* enqueue transaction to commit queue */
536 			list_add_tail(&tblk->cqueue, &log->cqueue);
537 
538 			LOGGC_UNLOCK(log);
539 		}
540 
541 		jfs_info("lmWriteRecord: lrd:0x%04x bp:0x%p pn:%d eor:0x%x",
542 			le16_to_cpu(lrd->type), log->bp, log->page, dstoffset);
543 
544 		/* page not full ? */
545 		if (dstoffset < LOGPSIZE - LOGPTLRSIZE)
546 			return lsn;
547 
548 	      pageFull:
549 		/* page become full: move on to next page */
550 		lmNextPage(log);
551 
552 		bp = (struct lbuf *) log->bp;
553 		lp = (struct logpage *) bp->l_ldata;
554 		dstoffset = LOGPHDRSIZE;
555 		src += nbytes;
556 	}
557 
558 	return lsn;
559 }
560 
561 
562 /*
563  * NAME:	lmNextPage()
564  *
565  * FUNCTION:	write current page and allocate next page.
566  *
567  * PARAMETER:	log
568  *
569  * RETURN:	0
570  *
571  * serialization: LOG_LOCK() held on entry/exit
572  */
573 static int lmNextPage(struct jfs_log * log)
574 {
575 	struct logpage *lp;
576 	int lspn;		/* log sequence page number */
577 	int pn;			/* current page number */
578 	struct lbuf *bp;
579 	struct lbuf *nextbp;
580 	struct tblock *tblk;
581 
582 	/* get current log page number and log sequence page number */
583 	pn = log->page;
584 	bp = log->bp;
585 	lp = (struct logpage *) bp->l_ldata;
586 	lspn = le32_to_cpu(lp->h.page);
587 
588 	LOGGC_LOCK(log);
589 
590 	/*
591 	 *	write or queue the full page at the tail of write queue
592 	 */
593 	/* get the tail tblk on commit queue */
594 	if (list_empty(&log->cqueue))
595 		tblk = NULL;
596 	else
597 		tblk = list_entry(log->cqueue.prev, struct tblock, cqueue);
598 
599 	/* every tblk who has COMMIT record on the current page,
600 	 * and has not been committed, must be on commit queue
601 	 * since tblk is queued at commit queueu at the time
602 	 * of writing its COMMIT record on the page before
603 	 * page becomes full (even though the tblk thread
604 	 * who wrote COMMIT record may have been suspended
605 	 * currently);
606 	 */
607 
608 	/* is page bound with outstanding tail tblk ? */
609 	if (tblk && tblk->pn == pn) {
610 		/* mark tblk for end-of-page */
611 		tblk->flag |= tblkGC_EOP;
612 
613 		if (log->cflag & logGC_PAGEOUT) {
614 			/* if page is not already on write queue,
615 			 * just enqueue (no lbmWRITE to prevent redrive)
616 			 * buffer to wqueue to ensure correct serial order
617 			 * of the pages since log pages will be added
618 			 * continuously
619 			 */
620 			if (bp->l_wqnext == NULL)
621 				lbmWrite(log, bp, 0, 0);
622 		} else {
623 			/*
624 			 * No current GC leader, initiate group commit
625 			 */
626 			log->cflag |= logGC_PAGEOUT;
627 			lmGCwrite(log, 0);
628 		}
629 	}
630 	/* page is not bound with outstanding tblk:
631 	 * init write or mark it to be redriven (lbmWRITE)
632 	 */
633 	else {
634 		/* finalize the page */
635 		bp->l_ceor = bp->l_eor;
636 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
637 		lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmFREE, 0);
638 	}
639 	LOGGC_UNLOCK(log);
640 
641 	/*
642 	 *	allocate/initialize next page
643 	 */
644 	/* if log wraps, the first data page of log is 2
645 	 * (0 never used, 1 is superblock).
646 	 */
647 	log->page = (pn == log->size - 1) ? 2 : pn + 1;
648 	log->eor = LOGPHDRSIZE;	/* ? valid page empty/full at logRedo() */
649 
650 	/* allocate/initialize next log page buffer */
651 	nextbp = lbmAllocate(log, log->page);
652 	nextbp->l_eor = log->eor;
653 	log->bp = nextbp;
654 
655 	/* initialize next log page */
656 	lp = (struct logpage *) nextbp->l_ldata;
657 	lp->h.page = lp->t.page = cpu_to_le32(lspn + 1);
658 	lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE);
659 
660 	return 0;
661 }
662 
663 
664 /*
665  * NAME:	lmGroupCommit()
666  *
667  * FUNCTION:	group commit
668  *	initiate pageout of the pages with COMMIT in the order of
669  *	page number - redrive pageout of the page at the head of
670  *	pageout queue until full page has been written.
671  *
672  * RETURN:
673  *
674  * NOTE:
675  *	LOGGC_LOCK serializes log group commit queue, and
676  *	transaction blocks on the commit queue.
677  *	N.B. LOG_LOCK is NOT held during lmGroupCommit().
678  */
679 int lmGroupCommit(struct jfs_log * log, struct tblock * tblk)
680 {
681 	int rc = 0;
682 
683 	LOGGC_LOCK(log);
684 
685 	/* group committed already ? */
686 	if (tblk->flag & tblkGC_COMMITTED) {
687 		if (tblk->flag & tblkGC_ERROR)
688 			rc = -EIO;
689 
690 		LOGGC_UNLOCK(log);
691 		return rc;
692 	}
693 	jfs_info("lmGroup Commit: tblk = 0x%p, gcrtc = %d", tblk, log->gcrtc);
694 
695 	if (tblk->xflag & COMMIT_LAZY)
696 		tblk->flag |= tblkGC_LAZY;
697 
698 	if ((!(log->cflag & logGC_PAGEOUT)) && (!list_empty(&log->cqueue)) &&
699 	    (!(tblk->xflag & COMMIT_LAZY) || test_bit(log_FLUSH, &log->flag)
700 	     || jfs_tlocks_low)) {
701 		/*
702 		 * No pageout in progress
703 		 *
704 		 * start group commit as its group leader.
705 		 */
706 		log->cflag |= logGC_PAGEOUT;
707 
708 		lmGCwrite(log, 0);
709 	}
710 
711 	if (tblk->xflag & COMMIT_LAZY) {
712 		/*
713 		 * Lazy transactions can leave now
714 		 */
715 		LOGGC_UNLOCK(log);
716 		return 0;
717 	}
718 
719 	/* lmGCwrite gives up LOGGC_LOCK, check again */
720 
721 	if (tblk->flag & tblkGC_COMMITTED) {
722 		if (tblk->flag & tblkGC_ERROR)
723 			rc = -EIO;
724 
725 		LOGGC_UNLOCK(log);
726 		return rc;
727 	}
728 
729 	/* upcount transaction waiting for completion
730 	 */
731 	log->gcrtc++;
732 	tblk->flag |= tblkGC_READY;
733 
734 	__SLEEP_COND(tblk->gcwait, (tblk->flag & tblkGC_COMMITTED),
735 		     LOGGC_LOCK(log), LOGGC_UNLOCK(log));
736 
737 	/* removed from commit queue */
738 	if (tblk->flag & tblkGC_ERROR)
739 		rc = -EIO;
740 
741 	LOGGC_UNLOCK(log);
742 	return rc;
743 }
744 
745 /*
746  * NAME:	lmGCwrite()
747  *
748  * FUNCTION:	group commit write
749  *	initiate write of log page, building a group of all transactions
750  *	with commit records on that page.
751  *
752  * RETURN:	None
753  *
754  * NOTE:
755  *	LOGGC_LOCK must be held by caller.
756  *	N.B. LOG_LOCK is NOT held during lmGroupCommit().
757  */
758 static void lmGCwrite(struct jfs_log * log, int cant_write)
759 {
760 	struct lbuf *bp;
761 	struct logpage *lp;
762 	int gcpn;		/* group commit page number */
763 	struct tblock *tblk;
764 	struct tblock *xtblk = NULL;
765 
766 	/*
767 	 * build the commit group of a log page
768 	 *
769 	 * scan commit queue and make a commit group of all
770 	 * transactions with COMMIT records on the same log page.
771 	 */
772 	/* get the head tblk on the commit queue */
773 	gcpn = list_entry(log->cqueue.next, struct tblock, cqueue)->pn;
774 
775 	list_for_each_entry(tblk, &log->cqueue, cqueue) {
776 		if (tblk->pn != gcpn)
777 			break;
778 
779 		xtblk = tblk;
780 
781 		/* state transition: (QUEUE, READY) -> COMMIT */
782 		tblk->flag |= tblkGC_COMMIT;
783 	}
784 	tblk = xtblk;		/* last tblk of the page */
785 
786 	/*
787 	 * pageout to commit transactions on the log page.
788 	 */
789 	bp = (struct lbuf *) tblk->bp;
790 	lp = (struct logpage *) bp->l_ldata;
791 	/* is page already full ? */
792 	if (tblk->flag & tblkGC_EOP) {
793 		/* mark page to free at end of group commit of the page */
794 		tblk->flag &= ~tblkGC_EOP;
795 		tblk->flag |= tblkGC_FREE;
796 		bp->l_ceor = bp->l_eor;
797 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
798 		lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmGC,
799 			 cant_write);
800 		INCREMENT(lmStat.full_page);
801 	}
802 	/* page is not yet full */
803 	else {
804 		bp->l_ceor = tblk->eor;	/* ? bp->l_ceor = bp->l_eor; */
805 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
806 		lbmWrite(log, bp, lbmWRITE | lbmGC, cant_write);
807 		INCREMENT(lmStat.partial_page);
808 	}
809 }
810 
811 /*
812  * NAME:	lmPostGC()
813  *
814  * FUNCTION:	group commit post-processing
815  *	Processes transactions after their commit records have been written
816  *	to disk, redriving log I/O if necessary.
817  *
818  * RETURN:	None
819  *
820  * NOTE:
821  *	This routine is called a interrupt time by lbmIODone
822  */
823 static void lmPostGC(struct lbuf * bp)
824 {
825 	unsigned long flags;
826 	struct jfs_log *log = bp->l_log;
827 	struct logpage *lp;
828 	struct tblock *tblk, *temp;
829 
830 	//LOGGC_LOCK(log);
831 	spin_lock_irqsave(&log->gclock, flags);
832 	/*
833 	 * current pageout of group commit completed.
834 	 *
835 	 * remove/wakeup transactions from commit queue who were
836 	 * group committed with the current log page
837 	 */
838 	list_for_each_entry_safe(tblk, temp, &log->cqueue, cqueue) {
839 		if (!(tblk->flag & tblkGC_COMMIT))
840 			break;
841 		/* if transaction was marked GC_COMMIT then
842 		 * it has been shipped in the current pageout
843 		 * and made it to disk - it is committed.
844 		 */
845 
846 		if (bp->l_flag & lbmERROR)
847 			tblk->flag |= tblkGC_ERROR;
848 
849 		/* remove it from the commit queue */
850 		list_del(&tblk->cqueue);
851 		tblk->flag &= ~tblkGC_QUEUE;
852 
853 		if (tblk == log->flush_tblk) {
854 			/* we can stop flushing the log now */
855 			clear_bit(log_FLUSH, &log->flag);
856 			log->flush_tblk = NULL;
857 		}
858 
859 		jfs_info("lmPostGC: tblk = 0x%p, flag = 0x%x", tblk,
860 			 tblk->flag);
861 
862 		if (!(tblk->xflag & COMMIT_FORCE))
863 			/*
864 			 * Hand tblk over to lazy commit thread
865 			 */
866 			txLazyUnlock(tblk);
867 		else {
868 			/* state transition: COMMIT -> COMMITTED */
869 			tblk->flag |= tblkGC_COMMITTED;
870 
871 			if (tblk->flag & tblkGC_READY)
872 				log->gcrtc--;
873 
874 			LOGGC_WAKEUP(tblk);
875 		}
876 
877 		/* was page full before pageout ?
878 		 * (and this is the last tblk bound with the page)
879 		 */
880 		if (tblk->flag & tblkGC_FREE)
881 			lbmFree(bp);
882 		/* did page become full after pageout ?
883 		 * (and this is the last tblk bound with the page)
884 		 */
885 		else if (tblk->flag & tblkGC_EOP) {
886 			/* finalize the page */
887 			lp = (struct logpage *) bp->l_ldata;
888 			bp->l_ceor = bp->l_eor;
889 			lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
890 			jfs_info("lmPostGC: calling lbmWrite");
891 			lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmFREE,
892 				 1);
893 		}
894 
895 	}
896 
897 	/* are there any transactions who have entered lnGroupCommit()
898 	 * (whose COMMITs are after that of the last log page written.
899 	 * They are waiting for new group commit (above at (SLEEP 1))
900 	 * or lazy transactions are on a full (queued) log page,
901 	 * select the latest ready transaction as new group leader and
902 	 * wake her up to lead her group.
903 	 */
904 	if ((!list_empty(&log->cqueue)) &&
905 	    ((log->gcrtc > 0) || (tblk->bp->l_wqnext != NULL) ||
906 	     test_bit(log_FLUSH, &log->flag) || jfs_tlocks_low))
907 		/*
908 		 * Call lmGCwrite with new group leader
909 		 */
910 		lmGCwrite(log, 1);
911 
912 	/* no transaction are ready yet (transactions are only just
913 	 * queued (GC_QUEUE) and not entered for group commit yet).
914 	 * the first transaction entering group commit
915 	 * will elect herself as new group leader.
916 	 */
917 	else
918 		log->cflag &= ~logGC_PAGEOUT;
919 
920 	//LOGGC_UNLOCK(log);
921 	spin_unlock_irqrestore(&log->gclock, flags);
922 	return;
923 }
924 
925 /*
926  * NAME:	lmLogSync()
927  *
928  * FUNCTION:	write log SYNCPT record for specified log
929  *	if new sync address is available
930  *	(normally the case if sync() is executed by back-ground
931  *	process).
932  *	calculate new value of i_nextsync which determines when
933  *	this code is called again.
934  *
935  * PARAMETERS:	log	- log structure
936  *		hard_sync - 1 to force all metadata to be written
937  *
938  * RETURN:	0
939  *
940  * serialization: LOG_LOCK() held on entry/exit
941  */
942 static int lmLogSync(struct jfs_log * log, int hard_sync)
943 {
944 	int logsize;
945 	int written;		/* written since last syncpt */
946 	int free;		/* free space left available */
947 	int delta;		/* additional delta to write normally */
948 	int more;		/* additional write granted */
949 	struct lrd lrd;
950 	int lsn;
951 	struct logsyncblk *lp;
952 	unsigned long flags;
953 
954 	/* push dirty metapages out to disk */
955 	if (hard_sync)
956 		write_special_inodes(log, filemap_fdatawrite);
957 	else
958 		write_special_inodes(log, filemap_flush);
959 
960 	/*
961 	 *	forward syncpt
962 	 */
963 	/* if last sync is same as last syncpt,
964 	 * invoke sync point forward processing to update sync.
965 	 */
966 
967 	if (log->sync == log->syncpt) {
968 		LOGSYNC_LOCK(log, flags);
969 		if (list_empty(&log->synclist))
970 			log->sync = log->lsn;
971 		else {
972 			lp = list_entry(log->synclist.next,
973 					struct logsyncblk, synclist);
974 			log->sync = lp->lsn;
975 		}
976 		LOGSYNC_UNLOCK(log, flags);
977 
978 	}
979 
980 	/* if sync is different from last syncpt,
981 	 * write a SYNCPT record with syncpt = sync.
982 	 * reset syncpt = sync
983 	 */
984 	if (log->sync != log->syncpt) {
985 		lrd.logtid = 0;
986 		lrd.backchain = 0;
987 		lrd.type = cpu_to_le16(LOG_SYNCPT);
988 		lrd.length = 0;
989 		lrd.log.syncpt.sync = cpu_to_le32(log->sync);
990 		lsn = lmWriteRecord(log, NULL, &lrd, NULL);
991 
992 		log->syncpt = log->sync;
993 	} else
994 		lsn = log->lsn;
995 
996 	/*
997 	 *	setup next syncpt trigger (SWAG)
998 	 */
999 	logsize = log->logsize;
1000 
1001 	logdiff(written, lsn, log);
1002 	free = logsize - written;
1003 	delta = LOGSYNC_DELTA(logsize);
1004 	more = min(free / 2, delta);
1005 	if (more < 2 * LOGPSIZE) {
1006 		jfs_warn("\n ... Log Wrap ... Log Wrap ... Log Wrap ...\n");
1007 		/*
1008 		 *	log wrapping
1009 		 *
1010 		 * option 1 - panic ? No.!
1011 		 * option 2 - shutdown file systems
1012 		 *	      associated with log ?
1013 		 * option 3 - extend log ?
1014 		 * option 4 - second chance
1015 		 *
1016 		 * mark log wrapped, and continue.
1017 		 * when all active transactions are completed,
1018 		 * mark log valid for recovery.
1019 		 * if crashed during invalid state, log state
1020 		 * implies invalid log, forcing fsck().
1021 		 */
1022 		/* mark log state log wrap in log superblock */
1023 		/* log->state = LOGWRAP; */
1024 
1025 		/* reset sync point computation */
1026 		log->syncpt = log->sync = lsn;
1027 		log->nextsync = delta;
1028 	} else
1029 		/* next syncpt trigger = written + more */
1030 		log->nextsync = written + more;
1031 
1032 	/* if number of bytes written from last sync point is more
1033 	 * than 1/4 of the log size, stop new transactions from
1034 	 * starting until all current transactions are completed
1035 	 * by setting syncbarrier flag.
1036 	 */
1037 	if (!test_bit(log_SYNCBARRIER, &log->flag) &&
1038 	    (written > LOGSYNC_BARRIER(logsize)) && log->active) {
1039 		set_bit(log_SYNCBARRIER, &log->flag);
1040 		jfs_info("log barrier on: lsn=0x%x syncpt=0x%x", lsn,
1041 			 log->syncpt);
1042 		/*
1043 		 * We may have to initiate group commit
1044 		 */
1045 		jfs_flush_journal(log, 0);
1046 	}
1047 
1048 	return lsn;
1049 }
1050 
1051 /*
1052  * NAME:	jfs_syncpt
1053  *
1054  * FUNCTION:	write log SYNCPT record for specified log
1055  *
1056  * PARAMETERS:	log	  - log structure
1057  *		hard_sync - set to 1 to force metadata to be written
1058  */
1059 void jfs_syncpt(struct jfs_log *log, int hard_sync)
1060 {	LOG_LOCK(log);
1061 	lmLogSync(log, hard_sync);
1062 	LOG_UNLOCK(log);
1063 }
1064 
1065 /*
1066  * NAME:	lmLogOpen()
1067  *
1068  * FUNCTION:	open the log on first open;
1069  *	insert filesystem in the active list of the log.
1070  *
1071  * PARAMETER:	ipmnt	- file system mount inode
1072  *		iplog	- log inode (out)
1073  *
1074  * RETURN:
1075  *
1076  * serialization:
1077  */
1078 int lmLogOpen(struct super_block *sb)
1079 {
1080 	int rc;
1081 	struct block_device *bdev;
1082 	struct jfs_log *log;
1083 	struct jfs_sb_info *sbi = JFS_SBI(sb);
1084 
1085 	if (sbi->flag & JFS_NOINTEGRITY)
1086 		return open_dummy_log(sb);
1087 
1088 	if (sbi->mntflag & JFS_INLINELOG)
1089 		return open_inline_log(sb);
1090 
1091 	mutex_lock(&jfs_log_mutex);
1092 	list_for_each_entry(log, &jfs_external_logs, journal_list) {
1093 		if (log->bdev->bd_dev == sbi->logdev) {
1094 			if (memcmp(log->uuid, sbi->loguuid,
1095 				   sizeof(log->uuid))) {
1096 				jfs_warn("wrong uuid on JFS journal\n");
1097 				mutex_unlock(&jfs_log_mutex);
1098 				return -EINVAL;
1099 			}
1100 			/*
1101 			 * add file system to log active file system list
1102 			 */
1103 			if ((rc = lmLogFileSystem(log, sbi, 1))) {
1104 				mutex_unlock(&jfs_log_mutex);
1105 				return rc;
1106 			}
1107 			goto journal_found;
1108 		}
1109 	}
1110 
1111 	if (!(log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL))) {
1112 		mutex_unlock(&jfs_log_mutex);
1113 		return -ENOMEM;
1114 	}
1115 	INIT_LIST_HEAD(&log->sb_list);
1116 	init_waitqueue_head(&log->syncwait);
1117 
1118 	/*
1119 	 *	external log as separate logical volume
1120 	 *
1121 	 * file systems to log may have n-to-1 relationship;
1122 	 */
1123 
1124 	bdev = blkdev_get_by_dev(sbi->logdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
1125 				 log);
1126 	if (IS_ERR(bdev)) {
1127 		rc = PTR_ERR(bdev);
1128 		goto free;
1129 	}
1130 
1131 	log->bdev = bdev;
1132 	memcpy(log->uuid, sbi->loguuid, sizeof(log->uuid));
1133 
1134 	/*
1135 	 * initialize log:
1136 	 */
1137 	if ((rc = lmLogInit(log)))
1138 		goto close;
1139 
1140 	list_add(&log->journal_list, &jfs_external_logs);
1141 
1142 	/*
1143 	 * add file system to log active file system list
1144 	 */
1145 	if ((rc = lmLogFileSystem(log, sbi, 1)))
1146 		goto shutdown;
1147 
1148 journal_found:
1149 	LOG_LOCK(log);
1150 	list_add(&sbi->log_list, &log->sb_list);
1151 	sbi->log = log;
1152 	LOG_UNLOCK(log);
1153 
1154 	mutex_unlock(&jfs_log_mutex);
1155 	return 0;
1156 
1157 	/*
1158 	 *	unwind on error
1159 	 */
1160       shutdown:		/* unwind lbmLogInit() */
1161 	list_del(&log->journal_list);
1162 	lbmLogShutdown(log);
1163 
1164       close:		/* close external log device */
1165 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1166 
1167       free:		/* free log descriptor */
1168 	mutex_unlock(&jfs_log_mutex);
1169 	kfree(log);
1170 
1171 	jfs_warn("lmLogOpen: exit(%d)", rc);
1172 	return rc;
1173 }
1174 
1175 static int open_inline_log(struct super_block *sb)
1176 {
1177 	struct jfs_log *log;
1178 	int rc;
1179 
1180 	if (!(log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL)))
1181 		return -ENOMEM;
1182 	INIT_LIST_HEAD(&log->sb_list);
1183 	init_waitqueue_head(&log->syncwait);
1184 
1185 	set_bit(log_INLINELOG, &log->flag);
1186 	log->bdev = sb->s_bdev;
1187 	log->base = addressPXD(&JFS_SBI(sb)->logpxd);
1188 	log->size = lengthPXD(&JFS_SBI(sb)->logpxd) >>
1189 	    (L2LOGPSIZE - sb->s_blocksize_bits);
1190 	log->l2bsize = sb->s_blocksize_bits;
1191 	ASSERT(L2LOGPSIZE >= sb->s_blocksize_bits);
1192 
1193 	/*
1194 	 * initialize log.
1195 	 */
1196 	if ((rc = lmLogInit(log))) {
1197 		kfree(log);
1198 		jfs_warn("lmLogOpen: exit(%d)", rc);
1199 		return rc;
1200 	}
1201 
1202 	list_add(&JFS_SBI(sb)->log_list, &log->sb_list);
1203 	JFS_SBI(sb)->log = log;
1204 
1205 	return rc;
1206 }
1207 
1208 static int open_dummy_log(struct super_block *sb)
1209 {
1210 	int rc;
1211 
1212 	mutex_lock(&jfs_log_mutex);
1213 	if (!dummy_log) {
1214 		dummy_log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL);
1215 		if (!dummy_log) {
1216 			mutex_unlock(&jfs_log_mutex);
1217 			return -ENOMEM;
1218 		}
1219 		INIT_LIST_HEAD(&dummy_log->sb_list);
1220 		init_waitqueue_head(&dummy_log->syncwait);
1221 		dummy_log->no_integrity = 1;
1222 		/* Make up some stuff */
1223 		dummy_log->base = 0;
1224 		dummy_log->size = 1024;
1225 		rc = lmLogInit(dummy_log);
1226 		if (rc) {
1227 			kfree(dummy_log);
1228 			dummy_log = NULL;
1229 			mutex_unlock(&jfs_log_mutex);
1230 			return rc;
1231 		}
1232 	}
1233 
1234 	LOG_LOCK(dummy_log);
1235 	list_add(&JFS_SBI(sb)->log_list, &dummy_log->sb_list);
1236 	JFS_SBI(sb)->log = dummy_log;
1237 	LOG_UNLOCK(dummy_log);
1238 	mutex_unlock(&jfs_log_mutex);
1239 
1240 	return 0;
1241 }
1242 
1243 /*
1244  * NAME:	lmLogInit()
1245  *
1246  * FUNCTION:	log initialization at first log open.
1247  *
1248  *	logredo() (or logformat()) should have been run previously.
1249  *	initialize the log from log superblock.
1250  *	set the log state in the superblock to LOGMOUNT and
1251  *	write SYNCPT log record.
1252  *
1253  * PARAMETER:	log	- log structure
1254  *
1255  * RETURN:	0	- if ok
1256  *		-EINVAL	- bad log magic number or superblock dirty
1257  *		error returned from logwait()
1258  *
1259  * serialization: single first open thread
1260  */
1261 int lmLogInit(struct jfs_log * log)
1262 {
1263 	int rc = 0;
1264 	struct lrd lrd;
1265 	struct logsuper *logsuper;
1266 	struct lbuf *bpsuper;
1267 	struct lbuf *bp;
1268 	struct logpage *lp;
1269 	int lsn = 0;
1270 
1271 	jfs_info("lmLogInit: log:0x%p", log);
1272 
1273 	/* initialize the group commit serialization lock */
1274 	LOGGC_LOCK_INIT(log);
1275 
1276 	/* allocate/initialize the log write serialization lock */
1277 	LOG_LOCK_INIT(log);
1278 
1279 	LOGSYNC_LOCK_INIT(log);
1280 
1281 	INIT_LIST_HEAD(&log->synclist);
1282 
1283 	INIT_LIST_HEAD(&log->cqueue);
1284 	log->flush_tblk = NULL;
1285 
1286 	log->count = 0;
1287 
1288 	/*
1289 	 * initialize log i/o
1290 	 */
1291 	if ((rc = lbmLogInit(log)))
1292 		return rc;
1293 
1294 	if (!test_bit(log_INLINELOG, &log->flag))
1295 		log->l2bsize = L2LOGPSIZE;
1296 
1297 	/* check for disabled journaling to disk */
1298 	if (log->no_integrity) {
1299 		/*
1300 		 * Journal pages will still be filled.  When the time comes
1301 		 * to actually do the I/O, the write is not done, and the
1302 		 * endio routine is called directly.
1303 		 */
1304 		bp = lbmAllocate(log , 0);
1305 		log->bp = bp;
1306 		bp->l_pn = bp->l_eor = 0;
1307 	} else {
1308 		/*
1309 		 * validate log superblock
1310 		 */
1311 		if ((rc = lbmRead(log, 1, &bpsuper)))
1312 			goto errout10;
1313 
1314 		logsuper = (struct logsuper *) bpsuper->l_ldata;
1315 
1316 		if (logsuper->magic != cpu_to_le32(LOGMAGIC)) {
1317 			jfs_warn("*** Log Format Error ! ***");
1318 			rc = -EINVAL;
1319 			goto errout20;
1320 		}
1321 
1322 		/* logredo() should have been run successfully. */
1323 		if (logsuper->state != cpu_to_le32(LOGREDONE)) {
1324 			jfs_warn("*** Log Is Dirty ! ***");
1325 			rc = -EINVAL;
1326 			goto errout20;
1327 		}
1328 
1329 		/* initialize log from log superblock */
1330 		if (test_bit(log_INLINELOG,&log->flag)) {
1331 			if (log->size != le32_to_cpu(logsuper->size)) {
1332 				rc = -EINVAL;
1333 				goto errout20;
1334 			}
1335 			jfs_info("lmLogInit: inline log:0x%p base:0x%Lx "
1336 				 "size:0x%x", log,
1337 				 (unsigned long long) log->base, log->size);
1338 		} else {
1339 			if (memcmp(logsuper->uuid, log->uuid, 16)) {
1340 				jfs_warn("wrong uuid on JFS log device");
1341 				goto errout20;
1342 			}
1343 			log->size = le32_to_cpu(logsuper->size);
1344 			log->l2bsize = le32_to_cpu(logsuper->l2bsize);
1345 			jfs_info("lmLogInit: external log:0x%p base:0x%Lx "
1346 				 "size:0x%x", log,
1347 				 (unsigned long long) log->base, log->size);
1348 		}
1349 
1350 		log->page = le32_to_cpu(logsuper->end) / LOGPSIZE;
1351 		log->eor = le32_to_cpu(logsuper->end) - (LOGPSIZE * log->page);
1352 
1353 		/*
1354 		 * initialize for log append write mode
1355 		 */
1356 		/* establish current/end-of-log page/buffer */
1357 		if ((rc = lbmRead(log, log->page, &bp)))
1358 			goto errout20;
1359 
1360 		lp = (struct logpage *) bp->l_ldata;
1361 
1362 		jfs_info("lmLogInit: lsn:0x%x page:%d eor:%d:%d",
1363 			 le32_to_cpu(logsuper->end), log->page, log->eor,
1364 			 le16_to_cpu(lp->h.eor));
1365 
1366 		log->bp = bp;
1367 		bp->l_pn = log->page;
1368 		bp->l_eor = log->eor;
1369 
1370 		/* if current page is full, move on to next page */
1371 		if (log->eor >= LOGPSIZE - LOGPTLRSIZE)
1372 			lmNextPage(log);
1373 
1374 		/*
1375 		 * initialize log syncpoint
1376 		 */
1377 		/*
1378 		 * write the first SYNCPT record with syncpoint = 0
1379 		 * (i.e., log redo up to HERE !);
1380 		 * remove current page from lbm write queue at end of pageout
1381 		 * (to write log superblock update), but do not release to
1382 		 * freelist;
1383 		 */
1384 		lrd.logtid = 0;
1385 		lrd.backchain = 0;
1386 		lrd.type = cpu_to_le16(LOG_SYNCPT);
1387 		lrd.length = 0;
1388 		lrd.log.syncpt.sync = 0;
1389 		lsn = lmWriteRecord(log, NULL, &lrd, NULL);
1390 		bp = log->bp;
1391 		bp->l_ceor = bp->l_eor;
1392 		lp = (struct logpage *) bp->l_ldata;
1393 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
1394 		lbmWrite(log, bp, lbmWRITE | lbmSYNC, 0);
1395 		if ((rc = lbmIOWait(bp, 0)))
1396 			goto errout30;
1397 
1398 		/*
1399 		 * update/write superblock
1400 		 */
1401 		logsuper->state = cpu_to_le32(LOGMOUNT);
1402 		log->serial = le32_to_cpu(logsuper->serial) + 1;
1403 		logsuper->serial = cpu_to_le32(log->serial);
1404 		lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1405 		if ((rc = lbmIOWait(bpsuper, lbmFREE)))
1406 			goto errout30;
1407 	}
1408 
1409 	/* initialize logsync parameters */
1410 	log->logsize = (log->size - 2) << L2LOGPSIZE;
1411 	log->lsn = lsn;
1412 	log->syncpt = lsn;
1413 	log->sync = log->syncpt;
1414 	log->nextsync = LOGSYNC_DELTA(log->logsize);
1415 
1416 	jfs_info("lmLogInit: lsn:0x%x syncpt:0x%x sync:0x%x",
1417 		 log->lsn, log->syncpt, log->sync);
1418 
1419 	/*
1420 	 * initialize for lazy/group commit
1421 	 */
1422 	log->clsn = lsn;
1423 
1424 	return 0;
1425 
1426 	/*
1427 	 *	unwind on error
1428 	 */
1429       errout30:		/* release log page */
1430 	log->wqueue = NULL;
1431 	bp->l_wqnext = NULL;
1432 	lbmFree(bp);
1433 
1434       errout20:		/* release log superblock */
1435 	lbmFree(bpsuper);
1436 
1437       errout10:		/* unwind lbmLogInit() */
1438 	lbmLogShutdown(log);
1439 
1440 	jfs_warn("lmLogInit: exit(%d)", rc);
1441 	return rc;
1442 }
1443 
1444 
1445 /*
1446  * NAME:	lmLogClose()
1447  *
1448  * FUNCTION:	remove file system <ipmnt> from active list of log <iplog>
1449  *		and close it on last close.
1450  *
1451  * PARAMETER:	sb	- superblock
1452  *
1453  * RETURN:	errors from subroutines
1454  *
1455  * serialization:
1456  */
1457 int lmLogClose(struct super_block *sb)
1458 {
1459 	struct jfs_sb_info *sbi = JFS_SBI(sb);
1460 	struct jfs_log *log = sbi->log;
1461 	struct block_device *bdev;
1462 	int rc = 0;
1463 
1464 	jfs_info("lmLogClose: log:0x%p", log);
1465 
1466 	mutex_lock(&jfs_log_mutex);
1467 	LOG_LOCK(log);
1468 	list_del(&sbi->log_list);
1469 	LOG_UNLOCK(log);
1470 	sbi->log = NULL;
1471 
1472 	/*
1473 	 * We need to make sure all of the "written" metapages
1474 	 * actually make it to disk
1475 	 */
1476 	sync_blockdev(sb->s_bdev);
1477 
1478 	if (test_bit(log_INLINELOG, &log->flag)) {
1479 		/*
1480 		 *	in-line log in host file system
1481 		 */
1482 		rc = lmLogShutdown(log);
1483 		kfree(log);
1484 		goto out;
1485 	}
1486 
1487 	if (!log->no_integrity)
1488 		lmLogFileSystem(log, sbi, 0);
1489 
1490 	if (!list_empty(&log->sb_list))
1491 		goto out;
1492 
1493 	/*
1494 	 * TODO: ensure that the dummy_log is in a state to allow
1495 	 * lbmLogShutdown to deallocate all the buffers and call
1496 	 * kfree against dummy_log.  For now, leave dummy_log & its
1497 	 * buffers in memory, and resuse if another no-integrity mount
1498 	 * is requested.
1499 	 */
1500 	if (log->no_integrity)
1501 		goto out;
1502 
1503 	/*
1504 	 *	external log as separate logical volume
1505 	 */
1506 	list_del(&log->journal_list);
1507 	bdev = log->bdev;
1508 	rc = lmLogShutdown(log);
1509 
1510 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1511 
1512 	kfree(log);
1513 
1514       out:
1515 	mutex_unlock(&jfs_log_mutex);
1516 	jfs_info("lmLogClose: exit(%d)", rc);
1517 	return rc;
1518 }
1519 
1520 
1521 /*
1522  * NAME:	jfs_flush_journal()
1523  *
1524  * FUNCTION:	initiate write of any outstanding transactions to the journal
1525  *		and optionally wait until they are all written to disk
1526  *
1527  *		wait == 0  flush until latest txn is committed, don't wait
1528  *		wait == 1  flush until latest txn is committed, wait
1529  *		wait > 1   flush until all txn's are complete, wait
1530  */
1531 void jfs_flush_journal(struct jfs_log *log, int wait)
1532 {
1533 	int i;
1534 	struct tblock *target = NULL;
1535 
1536 	/* jfs_write_inode may call us during read-only mount */
1537 	if (!log)
1538 		return;
1539 
1540 	jfs_info("jfs_flush_journal: log:0x%p wait=%d", log, wait);
1541 
1542 	LOGGC_LOCK(log);
1543 
1544 	if (!list_empty(&log->cqueue)) {
1545 		/*
1546 		 * This ensures that we will keep writing to the journal as long
1547 		 * as there are unwritten commit records
1548 		 */
1549 		target = list_entry(log->cqueue.prev, struct tblock, cqueue);
1550 
1551 		if (test_bit(log_FLUSH, &log->flag)) {
1552 			/*
1553 			 * We're already flushing.
1554 			 * if flush_tblk is NULL, we are flushing everything,
1555 			 * so leave it that way.  Otherwise, update it to the
1556 			 * latest transaction
1557 			 */
1558 			if (log->flush_tblk)
1559 				log->flush_tblk = target;
1560 		} else {
1561 			/* Only flush until latest transaction is committed */
1562 			log->flush_tblk = target;
1563 			set_bit(log_FLUSH, &log->flag);
1564 
1565 			/*
1566 			 * Initiate I/O on outstanding transactions
1567 			 */
1568 			if (!(log->cflag & logGC_PAGEOUT)) {
1569 				log->cflag |= logGC_PAGEOUT;
1570 				lmGCwrite(log, 0);
1571 			}
1572 		}
1573 	}
1574 	if ((wait > 1) || test_bit(log_SYNCBARRIER, &log->flag)) {
1575 		/* Flush until all activity complete */
1576 		set_bit(log_FLUSH, &log->flag);
1577 		log->flush_tblk = NULL;
1578 	}
1579 
1580 	if (wait && target && !(target->flag & tblkGC_COMMITTED)) {
1581 		DECLARE_WAITQUEUE(__wait, current);
1582 
1583 		add_wait_queue(&target->gcwait, &__wait);
1584 		set_current_state(TASK_UNINTERRUPTIBLE);
1585 		LOGGC_UNLOCK(log);
1586 		schedule();
1587 		__set_current_state(TASK_RUNNING);
1588 		LOGGC_LOCK(log);
1589 		remove_wait_queue(&target->gcwait, &__wait);
1590 	}
1591 	LOGGC_UNLOCK(log);
1592 
1593 	if (wait < 2)
1594 		return;
1595 
1596 	write_special_inodes(log, filemap_fdatawrite);
1597 
1598 	/*
1599 	 * If there was recent activity, we may need to wait
1600 	 * for the lazycommit thread to catch up
1601 	 */
1602 	if ((!list_empty(&log->cqueue)) || !list_empty(&log->synclist)) {
1603 		for (i = 0; i < 200; i++) {	/* Too much? */
1604 			msleep(250);
1605 			write_special_inodes(log, filemap_fdatawrite);
1606 			if (list_empty(&log->cqueue) &&
1607 			    list_empty(&log->synclist))
1608 				break;
1609 		}
1610 	}
1611 	assert(list_empty(&log->cqueue));
1612 
1613 #ifdef CONFIG_JFS_DEBUG
1614 	if (!list_empty(&log->synclist)) {
1615 		struct logsyncblk *lp;
1616 
1617 		printk(KERN_ERR "jfs_flush_journal: synclist not empty\n");
1618 		list_for_each_entry(lp, &log->synclist, synclist) {
1619 			if (lp->xflag & COMMIT_PAGE) {
1620 				struct metapage *mp = (struct metapage *)lp;
1621 				print_hex_dump(KERN_ERR, "metapage: ",
1622 					       DUMP_PREFIX_ADDRESS, 16, 4,
1623 					       mp, sizeof(struct metapage), 0);
1624 				print_hex_dump(KERN_ERR, "page: ",
1625 					       DUMP_PREFIX_ADDRESS, 16,
1626 					       sizeof(long), mp->page,
1627 					       sizeof(struct page), 0);
1628 			} else
1629 				print_hex_dump(KERN_ERR, "tblock:",
1630 					       DUMP_PREFIX_ADDRESS, 16, 4,
1631 					       lp, sizeof(struct tblock), 0);
1632 		}
1633 	}
1634 #else
1635 	WARN_ON(!list_empty(&log->synclist));
1636 #endif
1637 	clear_bit(log_FLUSH, &log->flag);
1638 }
1639 
1640 /*
1641  * NAME:	lmLogShutdown()
1642  *
1643  * FUNCTION:	log shutdown at last LogClose().
1644  *
1645  *		write log syncpt record.
1646  *		update super block to set redone flag to 0.
1647  *
1648  * PARAMETER:	log	- log inode
1649  *
1650  * RETURN:	0	- success
1651  *
1652  * serialization: single last close thread
1653  */
1654 int lmLogShutdown(struct jfs_log * log)
1655 {
1656 	int rc;
1657 	struct lrd lrd;
1658 	int lsn;
1659 	struct logsuper *logsuper;
1660 	struct lbuf *bpsuper;
1661 	struct lbuf *bp;
1662 	struct logpage *lp;
1663 
1664 	jfs_info("lmLogShutdown: log:0x%p", log);
1665 
1666 	jfs_flush_journal(log, 2);
1667 
1668 	/*
1669 	 * write the last SYNCPT record with syncpoint = 0
1670 	 * (i.e., log redo up to HERE !)
1671 	 */
1672 	lrd.logtid = 0;
1673 	lrd.backchain = 0;
1674 	lrd.type = cpu_to_le16(LOG_SYNCPT);
1675 	lrd.length = 0;
1676 	lrd.log.syncpt.sync = 0;
1677 
1678 	lsn = lmWriteRecord(log, NULL, &lrd, NULL);
1679 	bp = log->bp;
1680 	lp = (struct logpage *) bp->l_ldata;
1681 	lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
1682 	lbmWrite(log, log->bp, lbmWRITE | lbmRELEASE | lbmSYNC, 0);
1683 	lbmIOWait(log->bp, lbmFREE);
1684 	log->bp = NULL;
1685 
1686 	/*
1687 	 * synchronous update log superblock
1688 	 * mark log state as shutdown cleanly
1689 	 * (i.e., Log does not need to be replayed).
1690 	 */
1691 	if ((rc = lbmRead(log, 1, &bpsuper)))
1692 		goto out;
1693 
1694 	logsuper = (struct logsuper *) bpsuper->l_ldata;
1695 	logsuper->state = cpu_to_le32(LOGREDONE);
1696 	logsuper->end = cpu_to_le32(lsn);
1697 	lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1698 	rc = lbmIOWait(bpsuper, lbmFREE);
1699 
1700 	jfs_info("lmLogShutdown: lsn:0x%x page:%d eor:%d",
1701 		 lsn, log->page, log->eor);
1702 
1703       out:
1704 	/*
1705 	 * shutdown per log i/o
1706 	 */
1707 	lbmLogShutdown(log);
1708 
1709 	if (rc) {
1710 		jfs_warn("lmLogShutdown: exit(%d)", rc);
1711 	}
1712 	return rc;
1713 }
1714 
1715 
1716 /*
1717  * NAME:	lmLogFileSystem()
1718  *
1719  * FUNCTION:	insert (<activate> = true)/remove (<activate> = false)
1720  *	file system into/from log active file system list.
1721  *
1722  * PARAMETE:	log	- pointer to logs inode.
1723  *		fsdev	- kdev_t of filesystem.
1724  *		serial	- pointer to returned log serial number
1725  *		activate - insert/remove device from active list.
1726  *
1727  * RETURN:	0	- success
1728  *		errors returned by vms_iowait().
1729  */
1730 static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
1731 			   int activate)
1732 {
1733 	int rc = 0;
1734 	int i;
1735 	struct logsuper *logsuper;
1736 	struct lbuf *bpsuper;
1737 	char *uuid = sbi->uuid;
1738 
1739 	/*
1740 	 * insert/remove file system device to log active file system list.
1741 	 */
1742 	if ((rc = lbmRead(log, 1, &bpsuper)))
1743 		return rc;
1744 
1745 	logsuper = (struct logsuper *) bpsuper->l_ldata;
1746 	if (activate) {
1747 		for (i = 0; i < MAX_ACTIVE; i++)
1748 			if (!memcmp(logsuper->active[i].uuid, NULL_UUID, 16)) {
1749 				memcpy(logsuper->active[i].uuid, uuid, 16);
1750 				sbi->aggregate = i;
1751 				break;
1752 			}
1753 		if (i == MAX_ACTIVE) {
1754 			jfs_warn("Too many file systems sharing journal!");
1755 			lbmFree(bpsuper);
1756 			return -EMFILE;	/* Is there a better rc? */
1757 		}
1758 	} else {
1759 		for (i = 0; i < MAX_ACTIVE; i++)
1760 			if (!memcmp(logsuper->active[i].uuid, uuid, 16)) {
1761 				memcpy(logsuper->active[i].uuid, NULL_UUID, 16);
1762 				break;
1763 			}
1764 		if (i == MAX_ACTIVE) {
1765 			jfs_warn("Somebody stomped on the journal!");
1766 			lbmFree(bpsuper);
1767 			return -EIO;
1768 		}
1769 
1770 	}
1771 
1772 	/*
1773 	 * synchronous write log superblock:
1774 	 *
1775 	 * write sidestream bypassing write queue:
1776 	 * at file system mount, log super block is updated for
1777 	 * activation of the file system before any log record
1778 	 * (MOUNT record) of the file system, and at file system
1779 	 * unmount, all meta data for the file system has been
1780 	 * flushed before log super block is updated for deactivation
1781 	 * of the file system.
1782 	 */
1783 	lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1784 	rc = lbmIOWait(bpsuper, lbmFREE);
1785 
1786 	return rc;
1787 }
1788 
1789 /*
1790  *		log buffer manager (lbm)
1791  *		------------------------
1792  *
1793  * special purpose buffer manager supporting log i/o requirements.
1794  *
1795  * per log write queue:
1796  * log pageout occurs in serial order by fifo write queue and
1797  * restricting to a single i/o in pregress at any one time.
1798  * a circular singly-linked list
1799  * (log->wrqueue points to the tail, and buffers are linked via
1800  * bp->wrqueue field), and
1801  * maintains log page in pageout ot waiting for pageout in serial pageout.
1802  */
1803 
1804 /*
1805  *	lbmLogInit()
1806  *
1807  * initialize per log I/O setup at lmLogInit()
1808  */
1809 static int lbmLogInit(struct jfs_log * log)
1810 {				/* log inode */
1811 	int i;
1812 	struct lbuf *lbuf;
1813 
1814 	jfs_info("lbmLogInit: log:0x%p", log);
1815 
1816 	/* initialize current buffer cursor */
1817 	log->bp = NULL;
1818 
1819 	/* initialize log device write queue */
1820 	log->wqueue = NULL;
1821 
1822 	/*
1823 	 * Each log has its own buffer pages allocated to it.  These are
1824 	 * not managed by the page cache.  This ensures that a transaction
1825 	 * writing to the log does not block trying to allocate a page from
1826 	 * the page cache (for the log).  This would be bad, since page
1827 	 * allocation waits on the kswapd thread that may be committing inodes
1828 	 * which would cause log activity.  Was that clear?  I'm trying to
1829 	 * avoid deadlock here.
1830 	 */
1831 	init_waitqueue_head(&log->free_wait);
1832 
1833 	log->lbuf_free = NULL;
1834 
1835 	for (i = 0; i < LOGPAGES;) {
1836 		char *buffer;
1837 		uint offset;
1838 		struct page *page;
1839 
1840 		buffer = (char *) get_zeroed_page(GFP_KERNEL);
1841 		if (buffer == NULL)
1842 			goto error;
1843 		page = virt_to_page(buffer);
1844 		for (offset = 0; offset < PAGE_SIZE; offset += LOGPSIZE) {
1845 			lbuf = kmalloc(sizeof(struct lbuf), GFP_KERNEL);
1846 			if (lbuf == NULL) {
1847 				if (offset == 0)
1848 					free_page((unsigned long) buffer);
1849 				goto error;
1850 			}
1851 			if (offset) /* we already have one reference */
1852 				get_page(page);
1853 			lbuf->l_offset = offset;
1854 			lbuf->l_ldata = buffer + offset;
1855 			lbuf->l_page = page;
1856 			lbuf->l_log = log;
1857 			init_waitqueue_head(&lbuf->l_ioevent);
1858 
1859 			lbuf->l_freelist = log->lbuf_free;
1860 			log->lbuf_free = lbuf;
1861 			i++;
1862 		}
1863 	}
1864 
1865 	return (0);
1866 
1867       error:
1868 	lbmLogShutdown(log);
1869 	return -ENOMEM;
1870 }
1871 
1872 
1873 /*
1874  *	lbmLogShutdown()
1875  *
1876  * finalize per log I/O setup at lmLogShutdown()
1877  */
1878 static void lbmLogShutdown(struct jfs_log * log)
1879 {
1880 	struct lbuf *lbuf;
1881 
1882 	jfs_info("lbmLogShutdown: log:0x%p", log);
1883 
1884 	lbuf = log->lbuf_free;
1885 	while (lbuf) {
1886 		struct lbuf *next = lbuf->l_freelist;
1887 		__free_page(lbuf->l_page);
1888 		kfree(lbuf);
1889 		lbuf = next;
1890 	}
1891 }
1892 
1893 
1894 /*
1895  *	lbmAllocate()
1896  *
1897  * allocate an empty log buffer
1898  */
1899 static struct lbuf *lbmAllocate(struct jfs_log * log, int pn)
1900 {
1901 	struct lbuf *bp;
1902 	unsigned long flags;
1903 
1904 	/*
1905 	 * recycle from log buffer freelist if any
1906 	 */
1907 	LCACHE_LOCK(flags);
1908 	LCACHE_SLEEP_COND(log->free_wait, (bp = log->lbuf_free), flags);
1909 	log->lbuf_free = bp->l_freelist;
1910 	LCACHE_UNLOCK(flags);
1911 
1912 	bp->l_flag = 0;
1913 
1914 	bp->l_wqnext = NULL;
1915 	bp->l_freelist = NULL;
1916 
1917 	bp->l_pn = pn;
1918 	bp->l_blkno = log->base + (pn << (L2LOGPSIZE - log->l2bsize));
1919 	bp->l_ceor = 0;
1920 
1921 	return bp;
1922 }
1923 
1924 
1925 /*
1926  *	lbmFree()
1927  *
1928  * release a log buffer to freelist
1929  */
1930 static void lbmFree(struct lbuf * bp)
1931 {
1932 	unsigned long flags;
1933 
1934 	LCACHE_LOCK(flags);
1935 
1936 	lbmfree(bp);
1937 
1938 	LCACHE_UNLOCK(flags);
1939 }
1940 
1941 static void lbmfree(struct lbuf * bp)
1942 {
1943 	struct jfs_log *log = bp->l_log;
1944 
1945 	assert(bp->l_wqnext == NULL);
1946 
1947 	/*
1948 	 * return the buffer to head of freelist
1949 	 */
1950 	bp->l_freelist = log->lbuf_free;
1951 	log->lbuf_free = bp;
1952 
1953 	wake_up(&log->free_wait);
1954 	return;
1955 }
1956 
1957 
1958 /*
1959  * NAME:	lbmRedrive
1960  *
1961  * FUNCTION:	add a log buffer to the log redrive list
1962  *
1963  * PARAMETER:
1964  *	bp	- log buffer
1965  *
1966  * NOTES:
1967  *	Takes log_redrive_lock.
1968  */
1969 static inline void lbmRedrive(struct lbuf *bp)
1970 {
1971 	unsigned long flags;
1972 
1973 	spin_lock_irqsave(&log_redrive_lock, flags);
1974 	bp->l_redrive_next = log_redrive_list;
1975 	log_redrive_list = bp;
1976 	spin_unlock_irqrestore(&log_redrive_lock, flags);
1977 
1978 	wake_up_process(jfsIOthread);
1979 }
1980 
1981 
1982 /*
1983  *	lbmRead()
1984  */
1985 static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
1986 {
1987 	struct bio *bio;
1988 	struct lbuf *bp;
1989 
1990 	/*
1991 	 * allocate a log buffer
1992 	 */
1993 	*bpp = bp = lbmAllocate(log, pn);
1994 	jfs_info("lbmRead: bp:0x%p pn:0x%x", bp, pn);
1995 
1996 	bp->l_flag |= lbmREAD;
1997 
1998 	bio = bio_alloc(GFP_NOFS, 1);
1999 
2000 	bio->bi_sector = bp->l_blkno << (log->l2bsize - 9);
2001 	bio->bi_bdev = log->bdev;
2002 	bio->bi_io_vec[0].bv_page = bp->l_page;
2003 	bio->bi_io_vec[0].bv_len = LOGPSIZE;
2004 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
2005 
2006 	bio->bi_vcnt = 1;
2007 	bio->bi_idx = 0;
2008 	bio->bi_size = LOGPSIZE;
2009 
2010 	bio->bi_end_io = lbmIODone;
2011 	bio->bi_private = bp;
2012 	submit_bio(READ_SYNC, bio);
2013 
2014 	wait_event(bp->l_ioevent, (bp->l_flag != lbmREAD));
2015 
2016 	return 0;
2017 }
2018 
2019 
2020 /*
2021  *	lbmWrite()
2022  *
2023  * buffer at head of pageout queue stays after completion of
2024  * partial-page pageout and redriven by explicit initiation of
2025  * pageout by caller until full-page pageout is completed and
2026  * released.
2027  *
2028  * device driver i/o done redrives pageout of new buffer at
2029  * head of pageout queue when current buffer at head of pageout
2030  * queue is released at the completion of its full-page pageout.
2031  *
2032  * LOGGC_LOCK() serializes lbmWrite() by lmNextPage() and lmGroupCommit().
2033  * LCACHE_LOCK() serializes xflag between lbmWrite() and lbmIODone()
2034  */
2035 static void lbmWrite(struct jfs_log * log, struct lbuf * bp, int flag,
2036 		     int cant_block)
2037 {
2038 	struct lbuf *tail;
2039 	unsigned long flags;
2040 
2041 	jfs_info("lbmWrite: bp:0x%p flag:0x%x pn:0x%x", bp, flag, bp->l_pn);
2042 
2043 	/* map the logical block address to physical block address */
2044 	bp->l_blkno =
2045 	    log->base + (bp->l_pn << (L2LOGPSIZE - log->l2bsize));
2046 
2047 	LCACHE_LOCK(flags);		/* disable+lock */
2048 
2049 	/*
2050 	 * initialize buffer for device driver
2051 	 */
2052 	bp->l_flag = flag;
2053 
2054 	/*
2055 	 *	insert bp at tail of write queue associated with log
2056 	 *
2057 	 * (request is either for bp already/currently at head of queue
2058 	 * or new bp to be inserted at tail)
2059 	 */
2060 	tail = log->wqueue;
2061 
2062 	/* is buffer not already on write queue ? */
2063 	if (bp->l_wqnext == NULL) {
2064 		/* insert at tail of wqueue */
2065 		if (tail == NULL) {
2066 			log->wqueue = bp;
2067 			bp->l_wqnext = bp;
2068 		} else {
2069 			log->wqueue = bp;
2070 			bp->l_wqnext = tail->l_wqnext;
2071 			tail->l_wqnext = bp;
2072 		}
2073 
2074 		tail = bp;
2075 	}
2076 
2077 	/* is buffer at head of wqueue and for write ? */
2078 	if ((bp != tail->l_wqnext) || !(flag & lbmWRITE)) {
2079 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2080 		return;
2081 	}
2082 
2083 	LCACHE_UNLOCK(flags);	/* unlock+enable */
2084 
2085 	if (cant_block)
2086 		lbmRedrive(bp);
2087 	else if (flag & lbmSYNC)
2088 		lbmStartIO(bp);
2089 	else {
2090 		LOGGC_UNLOCK(log);
2091 		lbmStartIO(bp);
2092 		LOGGC_LOCK(log);
2093 	}
2094 }
2095 
2096 
2097 /*
2098  *	lbmDirectWrite()
2099  *
2100  * initiate pageout bypassing write queue for sidestream
2101  * (e.g., log superblock) write;
2102  */
2103 static void lbmDirectWrite(struct jfs_log * log, struct lbuf * bp, int flag)
2104 {
2105 	jfs_info("lbmDirectWrite: bp:0x%p flag:0x%x pn:0x%x",
2106 		 bp, flag, bp->l_pn);
2107 
2108 	/*
2109 	 * initialize buffer for device driver
2110 	 */
2111 	bp->l_flag = flag | lbmDIRECT;
2112 
2113 	/* map the logical block address to physical block address */
2114 	bp->l_blkno =
2115 	    log->base + (bp->l_pn << (L2LOGPSIZE - log->l2bsize));
2116 
2117 	/*
2118 	 *	initiate pageout of the page
2119 	 */
2120 	lbmStartIO(bp);
2121 }
2122 
2123 
2124 /*
2125  * NAME:	lbmStartIO()
2126  *
2127  * FUNCTION:	Interface to DD strategy routine
2128  *
2129  * RETURN:	none
2130  *
2131  * serialization: LCACHE_LOCK() is NOT held during log i/o;
2132  */
2133 static void lbmStartIO(struct lbuf * bp)
2134 {
2135 	struct bio *bio;
2136 	struct jfs_log *log = bp->l_log;
2137 
2138 	jfs_info("lbmStartIO\n");
2139 
2140 	bio = bio_alloc(GFP_NOFS, 1);
2141 	bio->bi_sector = bp->l_blkno << (log->l2bsize - 9);
2142 	bio->bi_bdev = log->bdev;
2143 	bio->bi_io_vec[0].bv_page = bp->l_page;
2144 	bio->bi_io_vec[0].bv_len = LOGPSIZE;
2145 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
2146 
2147 	bio->bi_vcnt = 1;
2148 	bio->bi_idx = 0;
2149 	bio->bi_size = LOGPSIZE;
2150 
2151 	bio->bi_end_io = lbmIODone;
2152 	bio->bi_private = bp;
2153 
2154 	/* check if journaling to disk has been disabled */
2155 	if (log->no_integrity) {
2156 		bio->bi_size = 0;
2157 		lbmIODone(bio, 0);
2158 	} else {
2159 		submit_bio(WRITE_SYNC, bio);
2160 		INCREMENT(lmStat.submitted);
2161 	}
2162 }
2163 
2164 
2165 /*
2166  *	lbmIOWait()
2167  */
2168 static int lbmIOWait(struct lbuf * bp, int flag)
2169 {
2170 	unsigned long flags;
2171 	int rc = 0;
2172 
2173 	jfs_info("lbmIOWait1: bp:0x%p flag:0x%x:0x%x", bp, bp->l_flag, flag);
2174 
2175 	LCACHE_LOCK(flags);		/* disable+lock */
2176 
2177 	LCACHE_SLEEP_COND(bp->l_ioevent, (bp->l_flag & lbmDONE), flags);
2178 
2179 	rc = (bp->l_flag & lbmERROR) ? -EIO : 0;
2180 
2181 	if (flag & lbmFREE)
2182 		lbmfree(bp);
2183 
2184 	LCACHE_UNLOCK(flags);	/* unlock+enable */
2185 
2186 	jfs_info("lbmIOWait2: bp:0x%p flag:0x%x:0x%x", bp, bp->l_flag, flag);
2187 	return rc;
2188 }
2189 
2190 /*
2191  *	lbmIODone()
2192  *
2193  * executed at INTIODONE level
2194  */
2195 static void lbmIODone(struct bio *bio, int error)
2196 {
2197 	struct lbuf *bp = bio->bi_private;
2198 	struct lbuf *nextbp, *tail;
2199 	struct jfs_log *log;
2200 	unsigned long flags;
2201 
2202 	/*
2203 	 * get back jfs buffer bound to the i/o buffer
2204 	 */
2205 	jfs_info("lbmIODone: bp:0x%p flag:0x%x", bp, bp->l_flag);
2206 
2207 	LCACHE_LOCK(flags);		/* disable+lock */
2208 
2209 	bp->l_flag |= lbmDONE;
2210 
2211 	if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
2212 		bp->l_flag |= lbmERROR;
2213 
2214 		jfs_err("lbmIODone: I/O error in JFS log");
2215 	}
2216 
2217 	bio_put(bio);
2218 
2219 	/*
2220 	 *	pagein completion
2221 	 */
2222 	if (bp->l_flag & lbmREAD) {
2223 		bp->l_flag &= ~lbmREAD;
2224 
2225 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2226 
2227 		/* wakeup I/O initiator */
2228 		LCACHE_WAKEUP(&bp->l_ioevent);
2229 
2230 		return;
2231 	}
2232 
2233 	/*
2234 	 *	pageout completion
2235 	 *
2236 	 * the bp at the head of write queue has completed pageout.
2237 	 *
2238 	 * if single-commit/full-page pageout, remove the current buffer
2239 	 * from head of pageout queue, and redrive pageout with
2240 	 * the new buffer at head of pageout queue;
2241 	 * otherwise, the partial-page pageout buffer stays at
2242 	 * the head of pageout queue to be redriven for pageout
2243 	 * by lmGroupCommit() until full-page pageout is completed.
2244 	 */
2245 	bp->l_flag &= ~lbmWRITE;
2246 	INCREMENT(lmStat.pagedone);
2247 
2248 	/* update committed lsn */
2249 	log = bp->l_log;
2250 	log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor;
2251 
2252 	if (bp->l_flag & lbmDIRECT) {
2253 		LCACHE_WAKEUP(&bp->l_ioevent);
2254 		LCACHE_UNLOCK(flags);
2255 		return;
2256 	}
2257 
2258 	tail = log->wqueue;
2259 
2260 	/* single element queue */
2261 	if (bp == tail) {
2262 		/* remove head buffer of full-page pageout
2263 		 * from log device write queue
2264 		 */
2265 		if (bp->l_flag & lbmRELEASE) {
2266 			log->wqueue = NULL;
2267 			bp->l_wqnext = NULL;
2268 		}
2269 	}
2270 	/* multi element queue */
2271 	else {
2272 		/* remove head buffer of full-page pageout
2273 		 * from log device write queue
2274 		 */
2275 		if (bp->l_flag & lbmRELEASE) {
2276 			nextbp = tail->l_wqnext = bp->l_wqnext;
2277 			bp->l_wqnext = NULL;
2278 
2279 			/*
2280 			 * redrive pageout of next page at head of write queue:
2281 			 * redrive next page without any bound tblk
2282 			 * (i.e., page w/o any COMMIT records), or
2283 			 * first page of new group commit which has been
2284 			 * queued after current page (subsequent pageout
2285 			 * is performed synchronously, except page without
2286 			 * any COMMITs) by lmGroupCommit() as indicated
2287 			 * by lbmWRITE flag;
2288 			 */
2289 			if (nextbp->l_flag & lbmWRITE) {
2290 				/*
2291 				 * We can't do the I/O at interrupt time.
2292 				 * The jfsIO thread can do it
2293 				 */
2294 				lbmRedrive(nextbp);
2295 			}
2296 		}
2297 	}
2298 
2299 	/*
2300 	 *	synchronous pageout:
2301 	 *
2302 	 * buffer has not necessarily been removed from write queue
2303 	 * (e.g., synchronous write of partial-page with COMMIT):
2304 	 * leave buffer for i/o initiator to dispose
2305 	 */
2306 	if (bp->l_flag & lbmSYNC) {
2307 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2308 
2309 		/* wakeup I/O initiator */
2310 		LCACHE_WAKEUP(&bp->l_ioevent);
2311 	}
2312 
2313 	/*
2314 	 *	Group Commit pageout:
2315 	 */
2316 	else if (bp->l_flag & lbmGC) {
2317 		LCACHE_UNLOCK(flags);
2318 		lmPostGC(bp);
2319 	}
2320 
2321 	/*
2322 	 *	asynchronous pageout:
2323 	 *
2324 	 * buffer must have been removed from write queue:
2325 	 * insert buffer at head of freelist where it can be recycled
2326 	 */
2327 	else {
2328 		assert(bp->l_flag & lbmRELEASE);
2329 		assert(bp->l_flag & lbmFREE);
2330 		lbmfree(bp);
2331 
2332 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2333 	}
2334 }
2335 
2336 int jfsIOWait(void *arg)
2337 {
2338 	struct lbuf *bp;
2339 
2340 	do {
2341 		spin_lock_irq(&log_redrive_lock);
2342 		while ((bp = log_redrive_list)) {
2343 			log_redrive_list = bp->l_redrive_next;
2344 			bp->l_redrive_next = NULL;
2345 			spin_unlock_irq(&log_redrive_lock);
2346 			lbmStartIO(bp);
2347 			spin_lock_irq(&log_redrive_lock);
2348 		}
2349 
2350 		if (freezing(current)) {
2351 			spin_unlock_irq(&log_redrive_lock);
2352 			refrigerator();
2353 		} else {
2354 			set_current_state(TASK_INTERRUPTIBLE);
2355 			spin_unlock_irq(&log_redrive_lock);
2356 			schedule();
2357 			__set_current_state(TASK_RUNNING);
2358 		}
2359 	} while (!kthread_should_stop());
2360 
2361 	jfs_info("jfsIOWait being killed!");
2362 	return 0;
2363 }
2364 
2365 /*
2366  * NAME:	lmLogFormat()/jfs_logform()
2367  *
2368  * FUNCTION:	format file system log
2369  *
2370  * PARAMETERS:
2371  *	log	- volume log
2372  *	logAddress - start address of log space in FS block
2373  *	logSize	- length of log space in FS block;
2374  *
2375  * RETURN:	0	- success
2376  *		-EIO	- i/o error
2377  *
2378  * XXX: We're synchronously writing one page at a time.  This needs to
2379  *	be improved by writing multiple pages at once.
2380  */
2381 int lmLogFormat(struct jfs_log *log, s64 logAddress, int logSize)
2382 {
2383 	int rc = -EIO;
2384 	struct jfs_sb_info *sbi;
2385 	struct logsuper *logsuper;
2386 	struct logpage *lp;
2387 	int lspn;		/* log sequence page number */
2388 	struct lrd *lrd_ptr;
2389 	int npages = 0;
2390 	struct lbuf *bp;
2391 
2392 	jfs_info("lmLogFormat: logAddress:%Ld logSize:%d",
2393 		 (long long)logAddress, logSize);
2394 
2395 	sbi = list_entry(log->sb_list.next, struct jfs_sb_info, log_list);
2396 
2397 	/* allocate a log buffer */
2398 	bp = lbmAllocate(log, 1);
2399 
2400 	npages = logSize >> sbi->l2nbperpage;
2401 
2402 	/*
2403 	 *	log space:
2404 	 *
2405 	 * page 0 - reserved;
2406 	 * page 1 - log superblock;
2407 	 * page 2 - log data page: A SYNC log record is written
2408 	 *	    into this page at logform time;
2409 	 * pages 3-N - log data page: set to empty log data pages;
2410 	 */
2411 	/*
2412 	 *	init log superblock: log page 1
2413 	 */
2414 	logsuper = (struct logsuper *) bp->l_ldata;
2415 
2416 	logsuper->magic = cpu_to_le32(LOGMAGIC);
2417 	logsuper->version = cpu_to_le32(LOGVERSION);
2418 	logsuper->state = cpu_to_le32(LOGREDONE);
2419 	logsuper->flag = cpu_to_le32(sbi->mntflag);	/* ? */
2420 	logsuper->size = cpu_to_le32(npages);
2421 	logsuper->bsize = cpu_to_le32(sbi->bsize);
2422 	logsuper->l2bsize = cpu_to_le32(sbi->l2bsize);
2423 	logsuper->end = cpu_to_le32(2 * LOGPSIZE + LOGPHDRSIZE + LOGRDSIZE);
2424 
2425 	bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
2426 	bp->l_blkno = logAddress + sbi->nbperpage;
2427 	lbmStartIO(bp);
2428 	if ((rc = lbmIOWait(bp, 0)))
2429 		goto exit;
2430 
2431 	/*
2432 	 *	init pages 2 to npages-1 as log data pages:
2433 	 *
2434 	 * log page sequence number (lpsn) initialization:
2435 	 *
2436 	 * pn:   0     1     2     3                 n-1
2437 	 *       +-----+-----+=====+=====+===.....===+=====+
2438 	 * lspn:             N-1   0     1           N-2
2439 	 *                   <--- N page circular file ---->
2440 	 *
2441 	 * the N (= npages-2) data pages of the log is maintained as
2442 	 * a circular file for the log records;
2443 	 * lpsn grows by 1 monotonically as each log page is written
2444 	 * to the circular file of the log;
2445 	 * and setLogpage() will not reset the page number even if
2446 	 * the eor is equal to LOGPHDRSIZE. In order for binary search
2447 	 * still work in find log end process, we have to simulate the
2448 	 * log wrap situation at the log format time.
2449 	 * The 1st log page written will have the highest lpsn. Then
2450 	 * the succeeding log pages will have ascending order of
2451 	 * the lspn starting from 0, ... (N-2)
2452 	 */
2453 	lp = (struct logpage *) bp->l_ldata;
2454 	/*
2455 	 * initialize 1st log page to be written: lpsn = N - 1,
2456 	 * write a SYNCPT log record is written to this page
2457 	 */
2458 	lp->h.page = lp->t.page = cpu_to_le32(npages - 3);
2459 	lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE + LOGRDSIZE);
2460 
2461 	lrd_ptr = (struct lrd *) &lp->data;
2462 	lrd_ptr->logtid = 0;
2463 	lrd_ptr->backchain = 0;
2464 	lrd_ptr->type = cpu_to_le16(LOG_SYNCPT);
2465 	lrd_ptr->length = 0;
2466 	lrd_ptr->log.syncpt.sync = 0;
2467 
2468 	bp->l_blkno += sbi->nbperpage;
2469 	bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
2470 	lbmStartIO(bp);
2471 	if ((rc = lbmIOWait(bp, 0)))
2472 		goto exit;
2473 
2474 	/*
2475 	 *	initialize succeeding log pages: lpsn = 0, 1, ..., (N-2)
2476 	 */
2477 	for (lspn = 0; lspn < npages - 3; lspn++) {
2478 		lp->h.page = lp->t.page = cpu_to_le32(lspn);
2479 		lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE);
2480 
2481 		bp->l_blkno += sbi->nbperpage;
2482 		bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
2483 		lbmStartIO(bp);
2484 		if ((rc = lbmIOWait(bp, 0)))
2485 			goto exit;
2486 	}
2487 
2488 	rc = 0;
2489 exit:
2490 	/*
2491 	 *	finalize log
2492 	 */
2493 	/* release the buffer */
2494 	lbmFree(bp);
2495 
2496 	return rc;
2497 }
2498 
2499 #ifdef CONFIG_JFS_STATISTICS
2500 static int jfs_lmstats_proc_show(struct seq_file *m, void *v)
2501 {
2502 	seq_printf(m,
2503 		       "JFS Logmgr stats\n"
2504 		       "================\n"
2505 		       "commits = %d\n"
2506 		       "writes submitted = %d\n"
2507 		       "writes completed = %d\n"
2508 		       "full pages submitted = %d\n"
2509 		       "partial pages submitted = %d\n",
2510 		       lmStat.commit,
2511 		       lmStat.submitted,
2512 		       lmStat.pagedone,
2513 		       lmStat.full_page,
2514 		       lmStat.partial_page);
2515 	return 0;
2516 }
2517 
2518 static int jfs_lmstats_proc_open(struct inode *inode, struct file *file)
2519 {
2520 	return single_open(file, jfs_lmstats_proc_show, NULL);
2521 }
2522 
2523 const struct file_operations jfs_lmstats_proc_fops = {
2524 	.owner		= THIS_MODULE,
2525 	.open		= jfs_lmstats_proc_open,
2526 	.read		= seq_read,
2527 	.llseek		= seq_lseek,
2528 	.release	= single_release,
2529 };
2530 #endif /* CONFIG_JFS_STATISTICS */
2531