xref: /linux/fs/jfs/jfs_logmgr.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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/smp_lock.h>
66 #include <linux/completion.h>
67 #include <linux/kthread.h>
68 #include <linux/buffer_head.h>		/* for sync_blockdev() */
69 #include <linux/bio.h>
70 #include <linux/suspend.h>
71 #include <linux/delay.h>
72 #include <linux/mutex.h>
73 #include "jfs_incore.h"
74 #include "jfs_filsys.h"
75 #include "jfs_metapage.h"
76 #include "jfs_superblock.h"
77 #include "jfs_txnmgr.h"
78 #include "jfs_debug.h"
79 
80 
81 /*
82  * lbuf's ready to be redriven.  Protected by log_redrive_lock (jfsIO thread)
83  */
84 static struct lbuf *log_redrive_list;
85 static DEFINE_SPINLOCK(log_redrive_lock);
86 
87 
88 /*
89  *	log read/write serialization (per log)
90  */
91 #define LOG_LOCK_INIT(log)	mutex_init(&(log)->loglock)
92 #define LOG_LOCK(log)		mutex_lock(&((log)->loglock))
93 #define LOG_UNLOCK(log)		mutex_unlock(&((log)->loglock))
94 
95 
96 /*
97  *	log group commit serialization (per log)
98  */
99 
100 #define LOGGC_LOCK_INIT(log)	spin_lock_init(&(log)->gclock)
101 #define LOGGC_LOCK(log)		spin_lock_irq(&(log)->gclock)
102 #define LOGGC_UNLOCK(log)	spin_unlock_irq(&(log)->gclock)
103 #define LOGGC_WAKEUP(tblk)	wake_up_all(&(tblk)->gcwait)
104 
105 /*
106  *	log sync serialization (per log)
107  */
108 #define	LOGSYNC_DELTA(logsize)		min((logsize)/8, 128*LOGPSIZE)
109 #define	LOGSYNC_BARRIER(logsize)	((logsize)/4)
110 /*
111 #define	LOGSYNC_DELTA(logsize)		min((logsize)/4, 256*LOGPSIZE)
112 #define	LOGSYNC_BARRIER(logsize)	((logsize)/2)
113 */
114 
115 
116 /*
117  *	log buffer cache synchronization
118  */
119 static DEFINE_SPINLOCK(jfsLCacheLock);
120 
121 #define	LCACHE_LOCK(flags)	spin_lock_irqsave(&jfsLCacheLock, flags)
122 #define	LCACHE_UNLOCK(flags)	spin_unlock_irqrestore(&jfsLCacheLock, flags)
123 
124 /*
125  * See __SLEEP_COND in jfs_locks.h
126  */
127 #define LCACHE_SLEEP_COND(wq, cond, flags)	\
128 do {						\
129 	if (cond)				\
130 		break;				\
131 	__SLEEP_COND(wq, cond, LCACHE_LOCK(flags), LCACHE_UNLOCK(flags)); \
132 } while (0)
133 
134 #define	LCACHE_WAKEUP(event)	wake_up(event)
135 
136 
137 /*
138  *	lbuf buffer cache (lCache) control
139  */
140 /* log buffer manager pageout control (cumulative, inclusive) */
141 #define	lbmREAD		0x0001
142 #define	lbmWRITE	0x0002	/* enqueue at tail of write queue;
143 				 * init pageout if at head of queue;
144 				 */
145 #define	lbmRELEASE	0x0004	/* remove from write queue
146 				 * at completion of pageout;
147 				 * do not free/recycle it yet:
148 				 * caller will free it;
149 				 */
150 #define	lbmSYNC		0x0008	/* do not return to freelist
151 				 * when removed from write queue;
152 				 */
153 #define lbmFREE		0x0010	/* return to freelist
154 				 * at completion of pageout;
155 				 * the buffer may be recycled;
156 				 */
157 #define	lbmDONE		0x0020
158 #define	lbmERROR	0x0040
159 #define lbmGC		0x0080	/* lbmIODone to perform post-GC processing
160 				 * of log page
161 				 */
162 #define lbmDIRECT	0x0100
163 
164 /*
165  * Global list of active external journals
166  */
167 static LIST_HEAD(jfs_external_logs);
168 static struct jfs_log *dummy_log = NULL;
169 static DEFINE_MUTEX(jfs_log_mutex);
170 
171 /*
172  * forward references
173  */
174 static int lmWriteRecord(struct jfs_log * log, struct tblock * tblk,
175 			 struct lrd * lrd, struct tlock * tlck);
176 
177 static int lmNextPage(struct jfs_log * log);
178 static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
179 			   int activate);
180 
181 static int open_inline_log(struct super_block *sb);
182 static int open_dummy_log(struct super_block *sb);
183 static int lbmLogInit(struct jfs_log * log);
184 static void lbmLogShutdown(struct jfs_log * log);
185 static struct lbuf *lbmAllocate(struct jfs_log * log, int);
186 static void lbmFree(struct lbuf * bp);
187 static void lbmfree(struct lbuf * bp);
188 static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp);
189 static void lbmWrite(struct jfs_log * log, struct lbuf * bp, int flag, int cant_block);
190 static void lbmDirectWrite(struct jfs_log * log, struct lbuf * bp, int flag);
191 static int lbmIOWait(struct lbuf * bp, int flag);
192 static bio_end_io_t lbmIODone;
193 static void lbmStartIO(struct lbuf * bp);
194 static void lmGCwrite(struct jfs_log * log, int cant_block);
195 static int lmLogSync(struct jfs_log * log, int hard_sync);
196 
197 
198 
199 /*
200  *	statistics
201  */
202 #ifdef CONFIG_JFS_STATISTICS
203 static struct lmStat {
204 	uint commit;		/* # of commit */
205 	uint pagedone;		/* # of page written */
206 	uint submitted;		/* # of pages submitted */
207 	uint full_page;		/* # of full pages submitted */
208 	uint partial_page;	/* # of partial pages submitted */
209 } lmStat;
210 #endif
211 
212 
213 /*
214  * NAME:	lmLog()
215  *
216  * FUNCTION:	write a log record;
217  *
218  * PARAMETER:
219  *
220  * RETURN:	lsn - offset to the next log record to write (end-of-log);
221  *		-1  - error;
222  *
223  * note: todo: log error handler
224  */
225 int lmLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
226 	  struct tlock * tlck)
227 {
228 	int lsn;
229 	int diffp, difft;
230 	struct metapage *mp = NULL;
231 	unsigned long flags;
232 
233 	jfs_info("lmLog: log:0x%p tblk:0x%p, lrd:0x%p tlck:0x%p",
234 		 log, tblk, lrd, tlck);
235 
236 	LOG_LOCK(log);
237 
238 	/* log by (out-of-transaction) JFS ? */
239 	if (tblk == NULL)
240 		goto writeRecord;
241 
242 	/* log from page ? */
243 	if (tlck == NULL ||
244 	    tlck->type & tlckBTROOT || (mp = tlck->mp) == NULL)
245 		goto writeRecord;
246 
247 	/*
248 	 *      initialize/update page/transaction recovery lsn
249 	 */
250 	lsn = log->lsn;
251 
252 	LOGSYNC_LOCK(log, flags);
253 
254 	/*
255 	 * initialize page lsn if first log write of the page
256 	 */
257 	if (mp->lsn == 0) {
258 		mp->log = log;
259 		mp->lsn = lsn;
260 		log->count++;
261 
262 		/* insert page at tail of logsynclist */
263 		list_add_tail(&mp->synclist, &log->synclist);
264 	}
265 
266 	/*
267 	 *      initialize/update lsn of tblock of the page
268 	 *
269 	 * transaction inherits oldest lsn of pages associated
270 	 * with allocation/deallocation of resources (their
271 	 * log records are used to reconstruct allocation map
272 	 * at recovery time: inode for inode allocation map,
273 	 * B+-tree index of extent descriptors for block
274 	 * allocation map);
275 	 * allocation map pages inherit transaction lsn at
276 	 * commit time to allow forwarding log syncpt past log
277 	 * records associated with allocation/deallocation of
278 	 * resources only after persistent map of these map pages
279 	 * have been updated and propagated to home.
280 	 */
281 	/*
282 	 * initialize transaction lsn:
283 	 */
284 	if (tblk->lsn == 0) {
285 		/* inherit lsn of its first page logged */
286 		tblk->lsn = mp->lsn;
287 		log->count++;
288 
289 		/* insert tblock after the page on logsynclist */
290 		list_add(&tblk->synclist, &mp->synclist);
291 	}
292 	/*
293 	 * update transaction lsn:
294 	 */
295 	else {
296 		/* inherit oldest/smallest lsn of page */
297 		logdiff(diffp, mp->lsn, log);
298 		logdiff(difft, tblk->lsn, log);
299 		if (diffp < difft) {
300 			/* update tblock lsn with page lsn */
301 			tblk->lsn = mp->lsn;
302 
303 			/* move tblock after page on logsynclist */
304 			list_move(&tblk->synclist, &mp->synclist);
305 		}
306 	}
307 
308 	LOGSYNC_UNLOCK(log, flags);
309 
310 	/*
311 	 *      write the log record
312 	 */
313       writeRecord:
314 	lsn = lmWriteRecord(log, tblk, lrd, tlck);
315 
316 	/*
317 	 * forward log syncpt if log reached next syncpt trigger
318 	 */
319 	logdiff(diffp, lsn, log);
320 	if (diffp >= log->nextsync)
321 		lsn = lmLogSync(log, 0);
322 
323 	/* update end-of-log lsn */
324 	log->lsn = lsn;
325 
326 	LOG_UNLOCK(log);
327 
328 	/* return end-of-log address */
329 	return lsn;
330 }
331 
332 /*
333  * NAME:	lmWriteRecord()
334  *
335  * FUNCTION:	move the log record to current log page
336  *
337  * PARAMETER:	cd	- commit descriptor
338  *
339  * RETURN:	end-of-log address
340  *
341  * serialization: LOG_LOCK() held on entry/exit
342  */
343 static int
344 lmWriteRecord(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
345 	      struct tlock * tlck)
346 {
347 	int lsn = 0;		/* end-of-log address */
348 	struct lbuf *bp;	/* dst log page buffer */
349 	struct logpage *lp;	/* dst log page */
350 	caddr_t dst;		/* destination address in log page */
351 	int dstoffset;		/* end-of-log offset in log page */
352 	int freespace;		/* free space in log page */
353 	caddr_t p;		/* src meta-data page */
354 	caddr_t src;
355 	int srclen;
356 	int nbytes;		/* number of bytes to move */
357 	int i;
358 	int len;
359 	struct linelock *linelock;
360 	struct lv *lv;
361 	struct lvd *lvd;
362 	int l2linesize;
363 
364 	len = 0;
365 
366 	/* retrieve destination log page to write */
367 	bp = (struct lbuf *) log->bp;
368 	lp = (struct logpage *) bp->l_ldata;
369 	dstoffset = log->eor;
370 
371 	/* any log data to write ? */
372 	if (tlck == NULL)
373 		goto moveLrd;
374 
375 	/*
376 	 *      move log record data
377 	 */
378 	/* retrieve source meta-data page to log */
379 	if (tlck->flag & tlckPAGELOCK) {
380 		p = (caddr_t) (tlck->mp->data);
381 		linelock = (struct linelock *) & tlck->lock;
382 	}
383 	/* retrieve source in-memory inode to log */
384 	else if (tlck->flag & tlckINODELOCK) {
385 		if (tlck->type & tlckDTREE)
386 			p = (caddr_t) &JFS_IP(tlck->ip)->i_dtroot;
387 		else
388 			p = (caddr_t) &JFS_IP(tlck->ip)->i_xtroot;
389 		linelock = (struct linelock *) & tlck->lock;
390 	}
391 #ifdef	_JFS_WIP
392 	else if (tlck->flag & tlckINLINELOCK) {
393 
394 		inlinelock = (struct inlinelock *) & tlck;
395 		p = (caddr_t) & inlinelock->pxd;
396 		linelock = (struct linelock *) & tlck;
397 	}
398 #endif				/* _JFS_WIP */
399 	else {
400 		jfs_err("lmWriteRecord: UFO tlck:0x%p", tlck);
401 		return 0;	/* Probably should trap */
402 	}
403 	l2linesize = linelock->l2linesize;
404 
405       moveData:
406 	ASSERT(linelock->index <= linelock->maxcnt);
407 
408 	lv = linelock->lv;
409 	for (i = 0; i < linelock->index; i++, lv++) {
410 		if (lv->length == 0)
411 			continue;
412 
413 		/* is page full ? */
414 		if (dstoffset >= LOGPSIZE - LOGPTLRSIZE) {
415 			/* page become full: move on to next page */
416 			lmNextPage(log);
417 
418 			bp = log->bp;
419 			lp = (struct logpage *) bp->l_ldata;
420 			dstoffset = LOGPHDRSIZE;
421 		}
422 
423 		/*
424 		 * move log vector data
425 		 */
426 		src = (u8 *) p + (lv->offset << l2linesize);
427 		srclen = lv->length << l2linesize;
428 		len += srclen;
429 		while (srclen > 0) {
430 			freespace = (LOGPSIZE - LOGPTLRSIZE) - dstoffset;
431 			nbytes = min(freespace, srclen);
432 			dst = (caddr_t) lp + dstoffset;
433 			memcpy(dst, src, nbytes);
434 			dstoffset += nbytes;
435 
436 			/* is page not full ? */
437 			if (dstoffset < LOGPSIZE - LOGPTLRSIZE)
438 				break;
439 
440 			/* page become full: move on to next page */
441 			lmNextPage(log);
442 
443 			bp = (struct lbuf *) log->bp;
444 			lp = (struct logpage *) bp->l_ldata;
445 			dstoffset = LOGPHDRSIZE;
446 
447 			srclen -= nbytes;
448 			src += nbytes;
449 		}
450 
451 		/*
452 		 * move log vector descriptor
453 		 */
454 		len += 4;
455 		lvd = (struct lvd *) ((caddr_t) lp + dstoffset);
456 		lvd->offset = cpu_to_le16(lv->offset);
457 		lvd->length = cpu_to_le16(lv->length);
458 		dstoffset += 4;
459 		jfs_info("lmWriteRecord: lv offset:%d length:%d",
460 			 lv->offset, lv->length);
461 	}
462 
463 	if ((i = linelock->next)) {
464 		linelock = (struct linelock *) lid_to_tlock(i);
465 		goto moveData;
466 	}
467 
468 	/*
469 	 *      move log record descriptor
470 	 */
471       moveLrd:
472 	lrd->length = cpu_to_le16(len);
473 
474 	src = (caddr_t) lrd;
475 	srclen = LOGRDSIZE;
476 
477 	while (srclen > 0) {
478 		freespace = (LOGPSIZE - LOGPTLRSIZE) - dstoffset;
479 		nbytes = min(freespace, srclen);
480 		dst = (caddr_t) lp + dstoffset;
481 		memcpy(dst, src, nbytes);
482 
483 		dstoffset += nbytes;
484 		srclen -= nbytes;
485 
486 		/* are there more to move than freespace of page ? */
487 		if (srclen)
488 			goto pageFull;
489 
490 		/*
491 		 * end of log record descriptor
492 		 */
493 
494 		/* update last log record eor */
495 		log->eor = dstoffset;
496 		bp->l_eor = dstoffset;
497 		lsn = (log->page << L2LOGPSIZE) + dstoffset;
498 
499 		if (lrd->type & cpu_to_le16(LOG_COMMIT)) {
500 			tblk->clsn = lsn;
501 			jfs_info("wr: tclsn:0x%x, beor:0x%x", tblk->clsn,
502 				 bp->l_eor);
503 
504 			INCREMENT(lmStat.commit);	/* # of commit */
505 
506 			/*
507 			 * enqueue tblock for group commit:
508 			 *
509 			 * enqueue tblock of non-trivial/synchronous COMMIT
510 			 * at tail of group commit queue
511 			 * (trivial/asynchronous COMMITs are ignored by
512 			 * group commit.)
513 			 */
514 			LOGGC_LOCK(log);
515 
516 			/* init tblock gc state */
517 			tblk->flag = tblkGC_QUEUE;
518 			tblk->bp = log->bp;
519 			tblk->pn = log->page;
520 			tblk->eor = log->eor;
521 
522 			/* enqueue transaction to commit queue */
523 			list_add_tail(&tblk->cqueue, &log->cqueue);
524 
525 			LOGGC_UNLOCK(log);
526 		}
527 
528 		jfs_info("lmWriteRecord: lrd:0x%04x bp:0x%p pn:%d eor:0x%x",
529 			le16_to_cpu(lrd->type), log->bp, log->page, dstoffset);
530 
531 		/* page not full ? */
532 		if (dstoffset < LOGPSIZE - LOGPTLRSIZE)
533 			return lsn;
534 
535 	      pageFull:
536 		/* page become full: move on to next page */
537 		lmNextPage(log);
538 
539 		bp = (struct lbuf *) log->bp;
540 		lp = (struct logpage *) bp->l_ldata;
541 		dstoffset = LOGPHDRSIZE;
542 		src += nbytes;
543 	}
544 
545 	return lsn;
546 }
547 
548 
549 /*
550  * NAME:	lmNextPage()
551  *
552  * FUNCTION:	write current page and allocate next page.
553  *
554  * PARAMETER:	log
555  *
556  * RETURN:	0
557  *
558  * serialization: LOG_LOCK() held on entry/exit
559  */
560 static int lmNextPage(struct jfs_log * log)
561 {
562 	struct logpage *lp;
563 	int lspn;		/* log sequence page number */
564 	int pn;			/* current page number */
565 	struct lbuf *bp;
566 	struct lbuf *nextbp;
567 	struct tblock *tblk;
568 
569 	/* get current log page number and log sequence page number */
570 	pn = log->page;
571 	bp = log->bp;
572 	lp = (struct logpage *) bp->l_ldata;
573 	lspn = le32_to_cpu(lp->h.page);
574 
575 	LOGGC_LOCK(log);
576 
577 	/*
578 	 *      write or queue the full page at the tail of write queue
579 	 */
580 	/* get the tail tblk on commit queue */
581 	if (list_empty(&log->cqueue))
582 		tblk = NULL;
583 	else
584 		tblk = list_entry(log->cqueue.prev, struct tblock, cqueue);
585 
586 	/* every tblk who has COMMIT record on the current page,
587 	 * and has not been committed, must be on commit queue
588 	 * since tblk is queued at commit queueu at the time
589 	 * of writing its COMMIT record on the page before
590 	 * page becomes full (even though the tblk thread
591 	 * who wrote COMMIT record may have been suspended
592 	 * currently);
593 	 */
594 
595 	/* is page bound with outstanding tail tblk ? */
596 	if (tblk && tblk->pn == pn) {
597 		/* mark tblk for end-of-page */
598 		tblk->flag |= tblkGC_EOP;
599 
600 		if (log->cflag & logGC_PAGEOUT) {
601 			/* if page is not already on write queue,
602 			 * just enqueue (no lbmWRITE to prevent redrive)
603 			 * buffer to wqueue to ensure correct serial order
604 			 * of the pages since log pages will be added
605 			 * continuously
606 			 */
607 			if (bp->l_wqnext == NULL)
608 				lbmWrite(log, bp, 0, 0);
609 		} else {
610 			/*
611 			 * No current GC leader, initiate group commit
612 			 */
613 			log->cflag |= logGC_PAGEOUT;
614 			lmGCwrite(log, 0);
615 		}
616 	}
617 	/* page is not bound with outstanding tblk:
618 	 * init write or mark it to be redriven (lbmWRITE)
619 	 */
620 	else {
621 		/* finalize the page */
622 		bp->l_ceor = bp->l_eor;
623 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
624 		lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmFREE, 0);
625 	}
626 	LOGGC_UNLOCK(log);
627 
628 	/*
629 	 *      allocate/initialize next page
630 	 */
631 	/* if log wraps, the first data page of log is 2
632 	 * (0 never used, 1 is superblock).
633 	 */
634 	log->page = (pn == log->size - 1) ? 2 : pn + 1;
635 	log->eor = LOGPHDRSIZE;	/* ? valid page empty/full at logRedo() */
636 
637 	/* allocate/initialize next log page buffer */
638 	nextbp = lbmAllocate(log, log->page);
639 	nextbp->l_eor = log->eor;
640 	log->bp = nextbp;
641 
642 	/* initialize next log page */
643 	lp = (struct logpage *) nextbp->l_ldata;
644 	lp->h.page = lp->t.page = cpu_to_le32(lspn + 1);
645 	lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE);
646 
647 	return 0;
648 }
649 
650 
651 /*
652  * NAME:	lmGroupCommit()
653  *
654  * FUNCTION:	group commit
655  *	initiate pageout of the pages with COMMIT in the order of
656  *	page number - redrive pageout of the page at the head of
657  *	pageout queue until full page has been written.
658  *
659  * RETURN:
660  *
661  * NOTE:
662  *	LOGGC_LOCK serializes log group commit queue, and
663  *	transaction blocks on the commit queue.
664  *	N.B. LOG_LOCK is NOT held during lmGroupCommit().
665  */
666 int lmGroupCommit(struct jfs_log * log, struct tblock * tblk)
667 {
668 	int rc = 0;
669 
670 	LOGGC_LOCK(log);
671 
672 	/* group committed already ? */
673 	if (tblk->flag & tblkGC_COMMITTED) {
674 		if (tblk->flag & tblkGC_ERROR)
675 			rc = -EIO;
676 
677 		LOGGC_UNLOCK(log);
678 		return rc;
679 	}
680 	jfs_info("lmGroup Commit: tblk = 0x%p, gcrtc = %d", tblk, log->gcrtc);
681 
682 	if (tblk->xflag & COMMIT_LAZY)
683 		tblk->flag |= tblkGC_LAZY;
684 
685 	if ((!(log->cflag & logGC_PAGEOUT)) && (!list_empty(&log->cqueue)) &&
686 	    (!(tblk->xflag & COMMIT_LAZY) || test_bit(log_FLUSH, &log->flag)
687 	     || jfs_tlocks_low)) {
688 		/*
689 		 * No pageout in progress
690 		 *
691 		 * start group commit as its group leader.
692 		 */
693 		log->cflag |= logGC_PAGEOUT;
694 
695 		lmGCwrite(log, 0);
696 	}
697 
698 	if (tblk->xflag & COMMIT_LAZY) {
699 		/*
700 		 * Lazy transactions can leave now
701 		 */
702 		LOGGC_UNLOCK(log);
703 		return 0;
704 	}
705 
706 	/* lmGCwrite gives up LOGGC_LOCK, check again */
707 
708 	if (tblk->flag & tblkGC_COMMITTED) {
709 		if (tblk->flag & tblkGC_ERROR)
710 			rc = -EIO;
711 
712 		LOGGC_UNLOCK(log);
713 		return rc;
714 	}
715 
716 	/* upcount transaction waiting for completion
717 	 */
718 	log->gcrtc++;
719 	tblk->flag |= tblkGC_READY;
720 
721 	__SLEEP_COND(tblk->gcwait, (tblk->flag & tblkGC_COMMITTED),
722 		     LOGGC_LOCK(log), LOGGC_UNLOCK(log));
723 
724 	/* removed from commit queue */
725 	if (tblk->flag & tblkGC_ERROR)
726 		rc = -EIO;
727 
728 	LOGGC_UNLOCK(log);
729 	return rc;
730 }
731 
732 /*
733  * NAME:	lmGCwrite()
734  *
735  * FUNCTION:	group commit write
736  *	initiate write of log page, building a group of all transactions
737  *	with commit records on that page.
738  *
739  * RETURN:	None
740  *
741  * NOTE:
742  *	LOGGC_LOCK must be held by caller.
743  *	N.B. LOG_LOCK is NOT held during lmGroupCommit().
744  */
745 static void lmGCwrite(struct jfs_log * log, int cant_write)
746 {
747 	struct lbuf *bp;
748 	struct logpage *lp;
749 	int gcpn;		/* group commit page number */
750 	struct tblock *tblk;
751 	struct tblock *xtblk = NULL;
752 
753 	/*
754 	 * build the commit group of a log page
755 	 *
756 	 * scan commit queue and make a commit group of all
757 	 * transactions with COMMIT records on the same log page.
758 	 */
759 	/* get the head tblk on the commit queue */
760 	gcpn = list_entry(log->cqueue.next, struct tblock, cqueue)->pn;
761 
762 	list_for_each_entry(tblk, &log->cqueue, cqueue) {
763 		if (tblk->pn != gcpn)
764 			break;
765 
766 		xtblk = tblk;
767 
768 		/* state transition: (QUEUE, READY) -> COMMIT */
769 		tblk->flag |= tblkGC_COMMIT;
770 	}
771 	tblk = xtblk;		/* last tblk of the page */
772 
773 	/*
774 	 * pageout to commit transactions on the log page.
775 	 */
776 	bp = (struct lbuf *) tblk->bp;
777 	lp = (struct logpage *) bp->l_ldata;
778 	/* is page already full ? */
779 	if (tblk->flag & tblkGC_EOP) {
780 		/* mark page to free at end of group commit of the page */
781 		tblk->flag &= ~tblkGC_EOP;
782 		tblk->flag |= tblkGC_FREE;
783 		bp->l_ceor = bp->l_eor;
784 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
785 		lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmGC,
786 			 cant_write);
787 		INCREMENT(lmStat.full_page);
788 	}
789 	/* page is not yet full */
790 	else {
791 		bp->l_ceor = tblk->eor;	/* ? bp->l_ceor = bp->l_eor; */
792 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
793 		lbmWrite(log, bp, lbmWRITE | lbmGC, cant_write);
794 		INCREMENT(lmStat.partial_page);
795 	}
796 }
797 
798 /*
799  * NAME:	lmPostGC()
800  *
801  * FUNCTION:	group commit post-processing
802  *	Processes transactions after their commit records have been written
803  *	to disk, redriving log I/O if necessary.
804  *
805  * RETURN:	None
806  *
807  * NOTE:
808  *	This routine is called a interrupt time by lbmIODone
809  */
810 static void lmPostGC(struct lbuf * bp)
811 {
812 	unsigned long flags;
813 	struct jfs_log *log = bp->l_log;
814 	struct logpage *lp;
815 	struct tblock *tblk, *temp;
816 
817 	//LOGGC_LOCK(log);
818 	spin_lock_irqsave(&log->gclock, flags);
819 	/*
820 	 * current pageout of group commit completed.
821 	 *
822 	 * remove/wakeup transactions from commit queue who were
823 	 * group committed with the current log page
824 	 */
825 	list_for_each_entry_safe(tblk, temp, &log->cqueue, cqueue) {
826 		if (!(tblk->flag & tblkGC_COMMIT))
827 			break;
828 		/* if transaction was marked GC_COMMIT then
829 		 * it has been shipped in the current pageout
830 		 * and made it to disk - it is committed.
831 		 */
832 
833 		if (bp->l_flag & lbmERROR)
834 			tblk->flag |= tblkGC_ERROR;
835 
836 		/* remove it from the commit queue */
837 		list_del(&tblk->cqueue);
838 		tblk->flag &= ~tblkGC_QUEUE;
839 
840 		if (tblk == log->flush_tblk) {
841 			/* we can stop flushing the log now */
842 			clear_bit(log_FLUSH, &log->flag);
843 			log->flush_tblk = NULL;
844 		}
845 
846 		jfs_info("lmPostGC: tblk = 0x%p, flag = 0x%x", tblk,
847 			 tblk->flag);
848 
849 		if (!(tblk->xflag & COMMIT_FORCE))
850 			/*
851 			 * Hand tblk over to lazy commit thread
852 			 */
853 			txLazyUnlock(tblk);
854 		else {
855 			/* state transition: COMMIT -> COMMITTED */
856 			tblk->flag |= tblkGC_COMMITTED;
857 
858 			if (tblk->flag & tblkGC_READY)
859 				log->gcrtc--;
860 
861 			LOGGC_WAKEUP(tblk);
862 		}
863 
864 		/* was page full before pageout ?
865 		 * (and this is the last tblk bound with the page)
866 		 */
867 		if (tblk->flag & tblkGC_FREE)
868 			lbmFree(bp);
869 		/* did page become full after pageout ?
870 		 * (and this is the last tblk bound with the page)
871 		 */
872 		else if (tblk->flag & tblkGC_EOP) {
873 			/* finalize the page */
874 			lp = (struct logpage *) bp->l_ldata;
875 			bp->l_ceor = bp->l_eor;
876 			lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
877 			jfs_info("lmPostGC: calling lbmWrite");
878 			lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmFREE,
879 				 1);
880 		}
881 
882 	}
883 
884 	/* are there any transactions who have entered lnGroupCommit()
885 	 * (whose COMMITs are after that of the last log page written.
886 	 * They are waiting for new group commit (above at (SLEEP 1))
887 	 * or lazy transactions are on a full (queued) log page,
888 	 * select the latest ready transaction as new group leader and
889 	 * wake her up to lead her group.
890 	 */
891 	if ((!list_empty(&log->cqueue)) &&
892 	    ((log->gcrtc > 0) || (tblk->bp->l_wqnext != NULL) ||
893 	     test_bit(log_FLUSH, &log->flag) || jfs_tlocks_low))
894 		/*
895 		 * Call lmGCwrite with new group leader
896 		 */
897 		lmGCwrite(log, 1);
898 
899 	/* no transaction are ready yet (transactions are only just
900 	 * queued (GC_QUEUE) and not entered for group commit yet).
901 	 * the first transaction entering group commit
902 	 * will elect herself as new group leader.
903 	 */
904 	else
905 		log->cflag &= ~logGC_PAGEOUT;
906 
907 	//LOGGC_UNLOCK(log);
908 	spin_unlock_irqrestore(&log->gclock, flags);
909 	return;
910 }
911 
912 /*
913  * NAME:	lmLogSync()
914  *
915  * FUNCTION:	write log SYNCPT record for specified log
916  *	if new sync address is available
917  *	(normally the case if sync() is executed by back-ground
918  *	process).
919  *	calculate new value of i_nextsync which determines when
920  *	this code is called again.
921  *
922  * PARAMETERS:	log	- log structure
923  * 		hard_sync - 1 to force all metadata to be written
924  *
925  * RETURN:	0
926  *
927  * serialization: LOG_LOCK() held on entry/exit
928  */
929 static int lmLogSync(struct jfs_log * log, int hard_sync)
930 {
931 	int logsize;
932 	int written;		/* written since last syncpt */
933 	int free;		/* free space left available */
934 	int delta;		/* additional delta to write normally */
935 	int more;		/* additional write granted */
936 	struct lrd lrd;
937 	int lsn;
938 	struct logsyncblk *lp;
939 	struct jfs_sb_info *sbi;
940 	unsigned long flags;
941 
942 	/* push dirty metapages out to disk */
943 	if (hard_sync)
944 		list_for_each_entry(sbi, &log->sb_list, log_list) {
945 			filemap_fdatawrite(sbi->ipbmap->i_mapping);
946 			filemap_fdatawrite(sbi->ipimap->i_mapping);
947 			filemap_fdatawrite(sbi->direct_inode->i_mapping);
948 		}
949 	else
950 		list_for_each_entry(sbi, &log->sb_list, log_list) {
951 			filemap_flush(sbi->ipbmap->i_mapping);
952 			filemap_flush(sbi->ipimap->i_mapping);
953 			filemap_flush(sbi->direct_inode->i_mapping);
954 		}
955 
956 	/*
957 	 *      forward syncpt
958 	 */
959 	/* if last sync is same as last syncpt,
960 	 * invoke sync point forward processing to update sync.
961 	 */
962 
963 	if (log->sync == log->syncpt) {
964 		LOGSYNC_LOCK(log, flags);
965 		if (list_empty(&log->synclist))
966 			log->sync = log->lsn;
967 		else {
968 			lp = list_entry(log->synclist.next,
969 					struct logsyncblk, synclist);
970 			log->sync = lp->lsn;
971 		}
972 		LOGSYNC_UNLOCK(log, flags);
973 
974 	}
975 
976 	/* if sync is different from last syncpt,
977 	 * write a SYNCPT record with syncpt = sync.
978 	 * reset syncpt = sync
979 	 */
980 	if (log->sync != log->syncpt) {
981 		lrd.logtid = 0;
982 		lrd.backchain = 0;
983 		lrd.type = cpu_to_le16(LOG_SYNCPT);
984 		lrd.length = 0;
985 		lrd.log.syncpt.sync = cpu_to_le32(log->sync);
986 		lsn = lmWriteRecord(log, NULL, &lrd, NULL);
987 
988 		log->syncpt = log->sync;
989 	} else
990 		lsn = log->lsn;
991 
992 	/*
993 	 *      setup next syncpt trigger (SWAG)
994 	 */
995 	logsize = log->logsize;
996 
997 	logdiff(written, lsn, log);
998 	free = logsize - written;
999 	delta = LOGSYNC_DELTA(logsize);
1000 	more = min(free / 2, delta);
1001 	if (more < 2 * LOGPSIZE) {
1002 		jfs_warn("\n ... Log Wrap ... Log Wrap ... Log Wrap ...\n");
1003 		/*
1004 		 *      log wrapping
1005 		 *
1006 		 * option 1 - panic ? No.!
1007 		 * option 2 - shutdown file systems
1008 		 *            associated with log ?
1009 		 * option 3 - extend log ?
1010 		 */
1011 		/*
1012 		 * option 4 - second chance
1013 		 *
1014 		 * mark log wrapped, and continue.
1015 		 * when all active transactions are completed,
1016 		 * mark log vaild for recovery.
1017 		 * if crashed during invalid state, log state
1018 		 * implies invald log, forcing fsck().
1019 		 */
1020 		/* mark log state log wrap in log superblock */
1021 		/* log->state = LOGWRAP; */
1022 
1023 		/* reset sync point computation */
1024 		log->syncpt = log->sync = lsn;
1025 		log->nextsync = delta;
1026 	} else
1027 		/* next syncpt trigger = written + more */
1028 		log->nextsync = written + more;
1029 
1030 	/* if number of bytes written from last sync point is more
1031 	 * than 1/4 of the log size, stop new transactions from
1032 	 * starting until all current transactions are completed
1033 	 * by setting syncbarrier flag.
1034 	 */
1035 	if (!test_bit(log_SYNCBARRIER, &log->flag) &&
1036 	    (written > LOGSYNC_BARRIER(logsize)) && log->active) {
1037 		set_bit(log_SYNCBARRIER, &log->flag);
1038 		jfs_info("log barrier on: lsn=0x%x syncpt=0x%x", lsn,
1039 			 log->syncpt);
1040 		/*
1041 		 * We may have to initiate group commit
1042 		 */
1043 		jfs_flush_journal(log, 0);
1044 	}
1045 
1046 	return lsn;
1047 }
1048 
1049 /*
1050  * NAME:	jfs_syncpt
1051  *
1052  * FUNCTION:	write log SYNCPT record for specified log
1053  *
1054  * PARAMETERS:	log	  - log structure
1055  * 		hard_sync - set to 1 to force metadata to be written
1056  */
1057 void jfs_syncpt(struct jfs_log *log, int hard_sync)
1058 {	LOG_LOCK(log);
1059 	lmLogSync(log, hard_sync);
1060 	LOG_UNLOCK(log);
1061 }
1062 
1063 /*
1064  * NAME:	lmLogOpen()
1065  *
1066  * FUNCTION:    open the log on first open;
1067  *	insert filesystem in the active list of the log.
1068  *
1069  * PARAMETER:	ipmnt	- file system mount inode
1070  *		iplog 	- log inode (out)
1071  *
1072  * RETURN:
1073  *
1074  * serialization:
1075  */
1076 int lmLogOpen(struct super_block *sb)
1077 {
1078 	int rc;
1079 	struct block_device *bdev;
1080 	struct jfs_log *log;
1081 	struct jfs_sb_info *sbi = JFS_SBI(sb);
1082 
1083 	if (sbi->flag & JFS_NOINTEGRITY)
1084 		return open_dummy_log(sb);
1085 
1086 	if (sbi->mntflag & JFS_INLINELOG)
1087 		return open_inline_log(sb);
1088 
1089 	mutex_lock(&jfs_log_mutex);
1090 	list_for_each_entry(log, &jfs_external_logs, journal_list) {
1091 		if (log->bdev->bd_dev == sbi->logdev) {
1092 			if (memcmp(log->uuid, sbi->loguuid,
1093 				   sizeof(log->uuid))) {
1094 				jfs_warn("wrong uuid on JFS journal\n");
1095 				mutex_unlock(&jfs_log_mutex);
1096 				return -EINVAL;
1097 			}
1098 			/*
1099 			 * add file system to log active file system list
1100 			 */
1101 			if ((rc = lmLogFileSystem(log, sbi, 1))) {
1102 				mutex_unlock(&jfs_log_mutex);
1103 				return rc;
1104 			}
1105 			goto journal_found;
1106 		}
1107 	}
1108 
1109 	if (!(log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL))) {
1110 		mutex_unlock(&jfs_log_mutex);
1111 		return -ENOMEM;
1112 	}
1113 	INIT_LIST_HEAD(&log->sb_list);
1114 	init_waitqueue_head(&log->syncwait);
1115 
1116 	/*
1117 	 *      external log as separate logical volume
1118 	 *
1119 	 * file systems to log may have n-to-1 relationship;
1120 	 */
1121 
1122 	bdev = open_by_devnum(sbi->logdev, FMODE_READ|FMODE_WRITE);
1123 	if (IS_ERR(bdev)) {
1124 		rc = -PTR_ERR(bdev);
1125 		goto free;
1126 	}
1127 
1128 	if ((rc = bd_claim(bdev, log))) {
1129 		goto close;
1130 	}
1131 
1132 	log->bdev = bdev;
1133 	memcpy(log->uuid, sbi->loguuid, sizeof(log->uuid));
1134 
1135 	/*
1136 	 * initialize log:
1137 	 */
1138 	if ((rc = lmLogInit(log)))
1139 		goto unclaim;
1140 
1141 	list_add(&log->journal_list, &jfs_external_logs);
1142 
1143 	/*
1144 	 * add file system to log active file system list
1145 	 */
1146 	if ((rc = lmLogFileSystem(log, sbi, 1)))
1147 		goto shutdown;
1148 
1149 journal_found:
1150 	LOG_LOCK(log);
1151 	list_add(&sbi->log_list, &log->sb_list);
1152 	sbi->log = log;
1153 	LOG_UNLOCK(log);
1154 
1155 	mutex_unlock(&jfs_log_mutex);
1156 	return 0;
1157 
1158 	/*
1159 	 *      unwind on error
1160 	 */
1161       shutdown:		/* unwind lbmLogInit() */
1162 	list_del(&log->journal_list);
1163 	lbmLogShutdown(log);
1164 
1165       unclaim:
1166 	bd_release(bdev);
1167 
1168       close:		/* close external log device */
1169 	blkdev_put(bdev);
1170 
1171       free:		/* free log descriptor */
1172 	mutex_unlock(&jfs_log_mutex);
1173 	kfree(log);
1174 
1175 	jfs_warn("lmLogOpen: exit(%d)", rc);
1176 	return rc;
1177 }
1178 
1179 static int open_inline_log(struct super_block *sb)
1180 {
1181 	struct jfs_log *log;
1182 	int rc;
1183 
1184 	if (!(log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL)))
1185 		return -ENOMEM;
1186 	INIT_LIST_HEAD(&log->sb_list);
1187 	init_waitqueue_head(&log->syncwait);
1188 
1189 	set_bit(log_INLINELOG, &log->flag);
1190 	log->bdev = sb->s_bdev;
1191 	log->base = addressPXD(&JFS_SBI(sb)->logpxd);
1192 	log->size = lengthPXD(&JFS_SBI(sb)->logpxd) >>
1193 	    (L2LOGPSIZE - sb->s_blocksize_bits);
1194 	log->l2bsize = sb->s_blocksize_bits;
1195 	ASSERT(L2LOGPSIZE >= sb->s_blocksize_bits);
1196 
1197 	/*
1198 	 * initialize log.
1199 	 */
1200 	if ((rc = lmLogInit(log))) {
1201 		kfree(log);
1202 		jfs_warn("lmLogOpen: exit(%d)", rc);
1203 		return rc;
1204 	}
1205 
1206 	list_add(&JFS_SBI(sb)->log_list, &log->sb_list);
1207 	JFS_SBI(sb)->log = log;
1208 
1209 	return rc;
1210 }
1211 
1212 static int open_dummy_log(struct super_block *sb)
1213 {
1214 	int rc;
1215 
1216 	mutex_lock(&jfs_log_mutex);
1217 	if (!dummy_log) {
1218 		dummy_log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL);
1219 		if (!dummy_log) {
1220 			mutex_unlock(&jfs_log_mutex);
1221 			return -ENOMEM;
1222 		}
1223 		INIT_LIST_HEAD(&dummy_log->sb_list);
1224 		init_waitqueue_head(&dummy_log->syncwait);
1225 		dummy_log->no_integrity = 1;
1226 		/* Make up some stuff */
1227 		dummy_log->base = 0;
1228 		dummy_log->size = 1024;
1229 		rc = lmLogInit(dummy_log);
1230 		if (rc) {
1231 			kfree(dummy_log);
1232 			dummy_log = NULL;
1233 			mutex_unlock(&jfs_log_mutex);
1234 			return rc;
1235 		}
1236 	}
1237 
1238 	LOG_LOCK(dummy_log);
1239 	list_add(&JFS_SBI(sb)->log_list, &dummy_log->sb_list);
1240 	JFS_SBI(sb)->log = dummy_log;
1241 	LOG_UNLOCK(dummy_log);
1242 	mutex_unlock(&jfs_log_mutex);
1243 
1244 	return 0;
1245 }
1246 
1247 /*
1248  * NAME:	lmLogInit()
1249  *
1250  * FUNCTION:	log initialization at first log open.
1251  *
1252  *	logredo() (or logformat()) should have been run previously.
1253  *	initialize the log from log superblock.
1254  *	set the log state in the superblock to LOGMOUNT and
1255  *	write SYNCPT log record.
1256  *
1257  * PARAMETER:	log	- log structure
1258  *
1259  * RETURN:	0	- if ok
1260  *		-EINVAL	- bad log magic number or superblock dirty
1261  *		error returned from logwait()
1262  *
1263  * serialization: single first open thread
1264  */
1265 int lmLogInit(struct jfs_log * log)
1266 {
1267 	int rc = 0;
1268 	struct lrd lrd;
1269 	struct logsuper *logsuper;
1270 	struct lbuf *bpsuper;
1271 	struct lbuf *bp;
1272 	struct logpage *lp;
1273 	int lsn = 0;
1274 
1275 	jfs_info("lmLogInit: log:0x%p", log);
1276 
1277 	/* initialize the group commit serialization lock */
1278 	LOGGC_LOCK_INIT(log);
1279 
1280 	/* allocate/initialize the log write serialization lock */
1281 	LOG_LOCK_INIT(log);
1282 
1283 	LOGSYNC_LOCK_INIT(log);
1284 
1285 	INIT_LIST_HEAD(&log->synclist);
1286 
1287 	INIT_LIST_HEAD(&log->cqueue);
1288 	log->flush_tblk = NULL;
1289 
1290 	log->count = 0;
1291 
1292 	/*
1293 	 * initialize log i/o
1294 	 */
1295 	if ((rc = lbmLogInit(log)))
1296 		return rc;
1297 
1298 	if (!test_bit(log_INLINELOG, &log->flag))
1299 		log->l2bsize = L2LOGPSIZE;
1300 
1301 	/* check for disabled journaling to disk */
1302 	if (log->no_integrity) {
1303 		/*
1304 		 * Journal pages will still be filled.  When the time comes
1305 		 * to actually do the I/O, the write is not done, and the
1306 		 * endio routine is called directly.
1307 		 */
1308 		bp = lbmAllocate(log , 0);
1309 		log->bp = bp;
1310 		bp->l_pn = bp->l_eor = 0;
1311 	} else {
1312 		/*
1313 		 * validate log superblock
1314 		 */
1315 		if ((rc = lbmRead(log, 1, &bpsuper)))
1316 			goto errout10;
1317 
1318 		logsuper = (struct logsuper *) bpsuper->l_ldata;
1319 
1320 		if (logsuper->magic != cpu_to_le32(LOGMAGIC)) {
1321 			jfs_warn("*** Log Format Error ! ***");
1322 			rc = -EINVAL;
1323 			goto errout20;
1324 		}
1325 
1326 		/* logredo() should have been run successfully. */
1327 		if (logsuper->state != cpu_to_le32(LOGREDONE)) {
1328 			jfs_warn("*** Log Is Dirty ! ***");
1329 			rc = -EINVAL;
1330 			goto errout20;
1331 		}
1332 
1333 		/* initialize log from log superblock */
1334 		if (test_bit(log_INLINELOG,&log->flag)) {
1335 			if (log->size != le32_to_cpu(logsuper->size)) {
1336 				rc = -EINVAL;
1337 				goto errout20;
1338 			}
1339 			jfs_info("lmLogInit: inline log:0x%p base:0x%Lx "
1340 				 "size:0x%x", log,
1341 				 (unsigned long long) log->base, log->size);
1342 		} else {
1343 			if (memcmp(logsuper->uuid, log->uuid, 16)) {
1344 				jfs_warn("wrong uuid on JFS log device");
1345 				goto errout20;
1346 			}
1347 			log->size = le32_to_cpu(logsuper->size);
1348 			log->l2bsize = le32_to_cpu(logsuper->l2bsize);
1349 			jfs_info("lmLogInit: external log:0x%p base:0x%Lx "
1350 				 "size:0x%x", log,
1351 				 (unsigned long long) log->base, log->size);
1352 		}
1353 
1354 		log->page = le32_to_cpu(logsuper->end) / LOGPSIZE;
1355 		log->eor = le32_to_cpu(logsuper->end) - (LOGPSIZE * log->page);
1356 
1357 		/*
1358 		 * initialize for log append write mode
1359 		 */
1360 		/* establish current/end-of-log page/buffer */
1361 		if ((rc = lbmRead(log, log->page, &bp)))
1362 			goto errout20;
1363 
1364 		lp = (struct logpage *) bp->l_ldata;
1365 
1366 		jfs_info("lmLogInit: lsn:0x%x page:%d eor:%d:%d",
1367 			 le32_to_cpu(logsuper->end), log->page, log->eor,
1368 			 le16_to_cpu(lp->h.eor));
1369 
1370 		log->bp = bp;
1371 		bp->l_pn = log->page;
1372 		bp->l_eor = log->eor;
1373 
1374 		/* if current page is full, move on to next page */
1375 		if (log->eor >= LOGPSIZE - LOGPTLRSIZE)
1376 			lmNextPage(log);
1377 
1378 		/*
1379 		 * initialize log syncpoint
1380 		 */
1381 		/*
1382 		 * write the first SYNCPT record with syncpoint = 0
1383 		 * (i.e., log redo up to HERE !);
1384 		 * remove current page from lbm write queue at end of pageout
1385 		 * (to write log superblock update), but do not release to
1386 		 * freelist;
1387 		 */
1388 		lrd.logtid = 0;
1389 		lrd.backchain = 0;
1390 		lrd.type = cpu_to_le16(LOG_SYNCPT);
1391 		lrd.length = 0;
1392 		lrd.log.syncpt.sync = 0;
1393 		lsn = lmWriteRecord(log, NULL, &lrd, NULL);
1394 		bp = log->bp;
1395 		bp->l_ceor = bp->l_eor;
1396 		lp = (struct logpage *) bp->l_ldata;
1397 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
1398 		lbmWrite(log, bp, lbmWRITE | lbmSYNC, 0);
1399 		if ((rc = lbmIOWait(bp, 0)))
1400 			goto errout30;
1401 
1402 		/*
1403 		 * update/write superblock
1404 		 */
1405 		logsuper->state = cpu_to_le32(LOGMOUNT);
1406 		log->serial = le32_to_cpu(logsuper->serial) + 1;
1407 		logsuper->serial = cpu_to_le32(log->serial);
1408 		lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1409 		if ((rc = lbmIOWait(bpsuper, lbmFREE)))
1410 			goto errout30;
1411 	}
1412 
1413 	/* initialize logsync parameters */
1414 	log->logsize = (log->size - 2) << L2LOGPSIZE;
1415 	log->lsn = lsn;
1416 	log->syncpt = lsn;
1417 	log->sync = log->syncpt;
1418 	log->nextsync = LOGSYNC_DELTA(log->logsize);
1419 
1420 	jfs_info("lmLogInit: lsn:0x%x syncpt:0x%x sync:0x%x",
1421 		 log->lsn, log->syncpt, log->sync);
1422 
1423 	/*
1424 	 * initialize for lazy/group commit
1425 	 */
1426 	log->clsn = lsn;
1427 
1428 	return 0;
1429 
1430 	/*
1431 	 *      unwind on error
1432 	 */
1433       errout30:		/* release log page */
1434 	log->wqueue = NULL;
1435 	bp->l_wqnext = NULL;
1436 	lbmFree(bp);
1437 
1438       errout20:		/* release log superblock */
1439 	lbmFree(bpsuper);
1440 
1441       errout10:		/* unwind lbmLogInit() */
1442 	lbmLogShutdown(log);
1443 
1444 	jfs_warn("lmLogInit: exit(%d)", rc);
1445 	return rc;
1446 }
1447 
1448 
1449 /*
1450  * NAME:	lmLogClose()
1451  *
1452  * FUNCTION:	remove file system <ipmnt> from active list of log <iplog>
1453  *		and close it on last close.
1454  *
1455  * PARAMETER:	sb	- superblock
1456  *
1457  * RETURN:	errors from subroutines
1458  *
1459  * serialization:
1460  */
1461 int lmLogClose(struct super_block *sb)
1462 {
1463 	struct jfs_sb_info *sbi = JFS_SBI(sb);
1464 	struct jfs_log *log = sbi->log;
1465 	struct block_device *bdev;
1466 	int rc = 0;
1467 
1468 	jfs_info("lmLogClose: log:0x%p", log);
1469 
1470 	mutex_lock(&jfs_log_mutex);
1471 	LOG_LOCK(log);
1472 	list_del(&sbi->log_list);
1473 	LOG_UNLOCK(log);
1474 	sbi->log = NULL;
1475 
1476 	/*
1477 	 * We need to make sure all of the "written" metapages
1478 	 * actually make it to disk
1479 	 */
1480 	sync_blockdev(sb->s_bdev);
1481 
1482 	if (test_bit(log_INLINELOG, &log->flag)) {
1483 		/*
1484 		 *      in-line log in host file system
1485 		 */
1486 		rc = lmLogShutdown(log);
1487 		kfree(log);
1488 		goto out;
1489 	}
1490 
1491 	if (!log->no_integrity)
1492 		lmLogFileSystem(log, sbi, 0);
1493 
1494 	if (!list_empty(&log->sb_list))
1495 		goto out;
1496 
1497 	/*
1498 	 * TODO: ensure that the dummy_log is in a state to allow
1499 	 * lbmLogShutdown to deallocate all the buffers and call
1500 	 * kfree against dummy_log.  For now, leave dummy_log & its
1501 	 * buffers in memory, and resuse if another no-integrity mount
1502 	 * is requested.
1503 	 */
1504 	if (log->no_integrity)
1505 		goto out;
1506 
1507 	/*
1508 	 *      external log as separate logical volume
1509 	 */
1510 	list_del(&log->journal_list);
1511 	bdev = log->bdev;
1512 	rc = lmLogShutdown(log);
1513 
1514 	bd_release(bdev);
1515 	blkdev_put(bdev);
1516 
1517 	kfree(log);
1518 
1519       out:
1520 	mutex_unlock(&jfs_log_mutex);
1521 	jfs_info("lmLogClose: exit(%d)", rc);
1522 	return rc;
1523 }
1524 
1525 
1526 /*
1527  * NAME:	jfs_flush_journal()
1528  *
1529  * FUNCTION:	initiate write of any outstanding transactions to the journal
1530  *		and optionally wait until they are all written to disk
1531  *
1532  *		wait == 0  flush until latest txn is committed, don't wait
1533  *		wait == 1  flush until latest txn is committed, wait
1534  *		wait > 1   flush until all txn's are complete, wait
1535  */
1536 void jfs_flush_journal(struct jfs_log *log, int wait)
1537 {
1538 	int i;
1539 	struct tblock *target = NULL;
1540 	struct jfs_sb_info *sbi;
1541 
1542 	/* jfs_write_inode may call us during read-only mount */
1543 	if (!log)
1544 		return;
1545 
1546 	jfs_info("jfs_flush_journal: log:0x%p wait=%d", log, wait);
1547 
1548 	LOGGC_LOCK(log);
1549 
1550 	if (!list_empty(&log->cqueue)) {
1551 		/*
1552 		 * This ensures that we will keep writing to the journal as long
1553 		 * as there are unwritten commit records
1554 		 */
1555 		target = list_entry(log->cqueue.prev, struct tblock, cqueue);
1556 
1557 		if (test_bit(log_FLUSH, &log->flag)) {
1558 			/*
1559 			 * We're already flushing.
1560 			 * if flush_tblk is NULL, we are flushing everything,
1561 			 * so leave it that way.  Otherwise, update it to the
1562 			 * latest transaction
1563 			 */
1564 			if (log->flush_tblk)
1565 				log->flush_tblk = target;
1566 		} else {
1567 			/* Only flush until latest transaction is committed */
1568 			log->flush_tblk = target;
1569 			set_bit(log_FLUSH, &log->flag);
1570 
1571 			/*
1572 			 * Initiate I/O on outstanding transactions
1573 			 */
1574 			if (!(log->cflag & logGC_PAGEOUT)) {
1575 				log->cflag |= logGC_PAGEOUT;
1576 				lmGCwrite(log, 0);
1577 			}
1578 		}
1579 	}
1580 	if ((wait > 1) || test_bit(log_SYNCBARRIER, &log->flag)) {
1581 		/* Flush until all activity complete */
1582 		set_bit(log_FLUSH, &log->flag);
1583 		log->flush_tblk = NULL;
1584 	}
1585 
1586 	if (wait && target && !(target->flag & tblkGC_COMMITTED)) {
1587 		DECLARE_WAITQUEUE(__wait, current);
1588 
1589 		add_wait_queue(&target->gcwait, &__wait);
1590 		set_current_state(TASK_UNINTERRUPTIBLE);
1591 		LOGGC_UNLOCK(log);
1592 		schedule();
1593 		current->state = TASK_RUNNING;
1594 		LOGGC_LOCK(log);
1595 		remove_wait_queue(&target->gcwait, &__wait);
1596 	}
1597 	LOGGC_UNLOCK(log);
1598 
1599 	if (wait < 2)
1600 		return;
1601 
1602 	list_for_each_entry(sbi, &log->sb_list, log_list) {
1603 		filemap_fdatawrite(sbi->ipbmap->i_mapping);
1604 		filemap_fdatawrite(sbi->ipimap->i_mapping);
1605 		filemap_fdatawrite(sbi->direct_inode->i_mapping);
1606 	}
1607 
1608 	/*
1609 	 * If there was recent activity, we may need to wait
1610 	 * for the lazycommit thread to catch up
1611 	 */
1612 	if ((!list_empty(&log->cqueue)) || !list_empty(&log->synclist)) {
1613 		for (i = 0; i < 200; i++) {	/* Too much? */
1614 			msleep(250);
1615 			if (list_empty(&log->cqueue) &&
1616 			    list_empty(&log->synclist))
1617 				break;
1618 		}
1619 	}
1620 	assert(list_empty(&log->cqueue));
1621 
1622 #ifdef CONFIG_JFS_DEBUG
1623 	if (!list_empty(&log->synclist)) {
1624 		struct logsyncblk *lp;
1625 
1626 		list_for_each_entry(lp, &log->synclist, synclist) {
1627 			if (lp->xflag & COMMIT_PAGE) {
1628 				struct metapage *mp = (struct metapage *)lp;
1629 				dump_mem("orphan metapage", lp,
1630 					 sizeof(struct metapage));
1631 				dump_mem("page", mp->page, sizeof(struct page));
1632 			}
1633 			else
1634 				dump_mem("orphan tblock", lp,
1635 					 sizeof(struct tblock));
1636 		}
1637 	}
1638 #endif
1639 	//assert(list_empty(&log->synclist));
1640 	clear_bit(log_FLUSH, &log->flag);
1641 }
1642 
1643 /*
1644  * NAME:	lmLogShutdown()
1645  *
1646  * FUNCTION:	log shutdown at last LogClose().
1647  *
1648  *		write log syncpt record.
1649  *		update super block to set redone flag to 0.
1650  *
1651  * PARAMETER:	log	- log inode
1652  *
1653  * RETURN:	0	- success
1654  *
1655  * serialization: single last close thread
1656  */
1657 int lmLogShutdown(struct jfs_log * log)
1658 {
1659 	int rc;
1660 	struct lrd lrd;
1661 	int lsn;
1662 	struct logsuper *logsuper;
1663 	struct lbuf *bpsuper;
1664 	struct lbuf *bp;
1665 	struct logpage *lp;
1666 
1667 	jfs_info("lmLogShutdown: log:0x%p", log);
1668 
1669 	jfs_flush_journal(log, 2);
1670 
1671 	/*
1672 	 * write the last SYNCPT record with syncpoint = 0
1673 	 * (i.e., log redo up to HERE !)
1674 	 */
1675 	lrd.logtid = 0;
1676 	lrd.backchain = 0;
1677 	lrd.type = cpu_to_le16(LOG_SYNCPT);
1678 	lrd.length = 0;
1679 	lrd.log.syncpt.sync = 0;
1680 
1681 	lsn = lmWriteRecord(log, NULL, &lrd, NULL);
1682 	bp = log->bp;
1683 	lp = (struct logpage *) bp->l_ldata;
1684 	lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
1685 	lbmWrite(log, log->bp, lbmWRITE | lbmRELEASE | lbmSYNC, 0);
1686 	lbmIOWait(log->bp, lbmFREE);
1687 	log->bp = NULL;
1688 
1689 	/*
1690 	 * synchronous update log superblock
1691 	 * mark log state as shutdown cleanly
1692 	 * (i.e., Log does not need to be replayed).
1693 	 */
1694 	if ((rc = lbmRead(log, 1, &bpsuper)))
1695 		goto out;
1696 
1697 	logsuper = (struct logsuper *) bpsuper->l_ldata;
1698 	logsuper->state = cpu_to_le32(LOGREDONE);
1699 	logsuper->end = cpu_to_le32(lsn);
1700 	lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1701 	rc = lbmIOWait(bpsuper, lbmFREE);
1702 
1703 	jfs_info("lmLogShutdown: lsn:0x%x page:%d eor:%d",
1704 		 lsn, log->page, log->eor);
1705 
1706       out:
1707 	/*
1708 	 * shutdown per log i/o
1709 	 */
1710 	lbmLogShutdown(log);
1711 
1712 	if (rc) {
1713 		jfs_warn("lmLogShutdown: exit(%d)", rc);
1714 	}
1715 	return rc;
1716 }
1717 
1718 
1719 /*
1720  * NAME:	lmLogFileSystem()
1721  *
1722  * FUNCTION:	insert (<activate> = true)/remove (<activate> = false)
1723  *	file system into/from log active file system list.
1724  *
1725  * PARAMETE:	log	- pointer to logs inode.
1726  *		fsdev	- kdev_t of filesystem.
1727  *		serial  - pointer to returned log serial number
1728  *		activate - insert/remove device from active list.
1729  *
1730  * RETURN:	0	- success
1731  *		errors returned by vms_iowait().
1732  */
1733 static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
1734 			   int activate)
1735 {
1736 	int rc = 0;
1737 	int i;
1738 	struct logsuper *logsuper;
1739 	struct lbuf *bpsuper;
1740 	char *uuid = sbi->uuid;
1741 
1742 	/*
1743 	 * insert/remove file system device to log active file system list.
1744 	 */
1745 	if ((rc = lbmRead(log, 1, &bpsuper)))
1746 		return rc;
1747 
1748 	logsuper = (struct logsuper *) bpsuper->l_ldata;
1749 	if (activate) {
1750 		for (i = 0; i < MAX_ACTIVE; i++)
1751 			if (!memcmp(logsuper->active[i].uuid, NULL_UUID, 16)) {
1752 				memcpy(logsuper->active[i].uuid, uuid, 16);
1753 				sbi->aggregate = i;
1754 				break;
1755 			}
1756 		if (i == MAX_ACTIVE) {
1757 			jfs_warn("Too many file systems sharing journal!");
1758 			lbmFree(bpsuper);
1759 			return -EMFILE;	/* Is there a better rc? */
1760 		}
1761 	} else {
1762 		for (i = 0; i < MAX_ACTIVE; i++)
1763 			if (!memcmp(logsuper->active[i].uuid, uuid, 16)) {
1764 				memcpy(logsuper->active[i].uuid, NULL_UUID, 16);
1765 				break;
1766 			}
1767 		if (i == MAX_ACTIVE) {
1768 			jfs_warn("Somebody stomped on the journal!");
1769 			lbmFree(bpsuper);
1770 			return -EIO;
1771 		}
1772 
1773 	}
1774 
1775 	/*
1776 	 * synchronous write log superblock:
1777 	 *
1778 	 * write sidestream bypassing write queue:
1779 	 * at file system mount, log super block is updated for
1780 	 * activation of the file system before any log record
1781 	 * (MOUNT record) of the file system, and at file system
1782 	 * unmount, all meta data for the file system has been
1783 	 * flushed before log super block is updated for deactivation
1784 	 * of the file system.
1785 	 */
1786 	lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1787 	rc = lbmIOWait(bpsuper, lbmFREE);
1788 
1789 	return rc;
1790 }
1791 
1792 /*
1793  *		log buffer manager (lbm)
1794  *		------------------------
1795  *
1796  * special purpose buffer manager supporting log i/o requirements.
1797  *
1798  * per log write queue:
1799  * log pageout occurs in serial order by fifo write queue and
1800  * restricting to a single i/o in pregress at any one time.
1801  * a circular singly-linked list
1802  * (log->wrqueue points to the tail, and buffers are linked via
1803  * bp->wrqueue field), and
1804  * maintains log page in pageout ot waiting for pageout in serial pageout.
1805  */
1806 
1807 /*
1808  *	lbmLogInit()
1809  *
1810  * initialize per log I/O setup at lmLogInit()
1811  */
1812 static int lbmLogInit(struct jfs_log * log)
1813 {				/* log inode */
1814 	int i;
1815 	struct lbuf *lbuf;
1816 
1817 	jfs_info("lbmLogInit: log:0x%p", log);
1818 
1819 	/* initialize current buffer cursor */
1820 	log->bp = NULL;
1821 
1822 	/* initialize log device write queue */
1823 	log->wqueue = NULL;
1824 
1825 	/*
1826 	 * Each log has its own buffer pages allocated to it.  These are
1827 	 * not managed by the page cache.  This ensures that a transaction
1828 	 * writing to the log does not block trying to allocate a page from
1829 	 * the page cache (for the log).  This would be bad, since page
1830 	 * allocation waits on the kswapd thread that may be committing inodes
1831 	 * which would cause log activity.  Was that clear?  I'm trying to
1832 	 * avoid deadlock here.
1833 	 */
1834 	init_waitqueue_head(&log->free_wait);
1835 
1836 	log->lbuf_free = NULL;
1837 
1838 	for (i = 0; i < LOGPAGES;) {
1839 		char *buffer;
1840 		uint offset;
1841 		struct page *page;
1842 
1843 		buffer = (char *) get_zeroed_page(GFP_KERNEL);
1844 		if (buffer == NULL)
1845 			goto error;
1846 		page = virt_to_page(buffer);
1847 		for (offset = 0; offset < PAGE_SIZE; offset += LOGPSIZE) {
1848 			lbuf = kmalloc(sizeof(struct lbuf), GFP_KERNEL);
1849 			if (lbuf == NULL) {
1850 				if (offset == 0)
1851 					free_page((unsigned long) buffer);
1852 				goto error;
1853 			}
1854 			if (offset) /* we already have one reference */
1855 				get_page(page);
1856 			lbuf->l_offset = offset;
1857 			lbuf->l_ldata = buffer + offset;
1858 			lbuf->l_page = page;
1859 			lbuf->l_log = log;
1860 			init_waitqueue_head(&lbuf->l_ioevent);
1861 
1862 			lbuf->l_freelist = log->lbuf_free;
1863 			log->lbuf_free = lbuf;
1864 			i++;
1865 		}
1866 	}
1867 
1868 	return (0);
1869 
1870       error:
1871 	lbmLogShutdown(log);
1872 	return -ENOMEM;
1873 }
1874 
1875 
1876 /*
1877  *	lbmLogShutdown()
1878  *
1879  * finalize per log I/O setup at lmLogShutdown()
1880  */
1881 static void lbmLogShutdown(struct jfs_log * log)
1882 {
1883 	struct lbuf *lbuf;
1884 
1885 	jfs_info("lbmLogShutdown: log:0x%p", log);
1886 
1887 	lbuf = log->lbuf_free;
1888 	while (lbuf) {
1889 		struct lbuf *next = lbuf->l_freelist;
1890 		__free_page(lbuf->l_page);
1891 		kfree(lbuf);
1892 		lbuf = next;
1893 	}
1894 }
1895 
1896 
1897 /*
1898  *	lbmAllocate()
1899  *
1900  * allocate an empty log buffer
1901  */
1902 static struct lbuf *lbmAllocate(struct jfs_log * log, int pn)
1903 {
1904 	struct lbuf *bp;
1905 	unsigned long flags;
1906 
1907 	/*
1908 	 * recycle from log buffer freelist if any
1909 	 */
1910 	LCACHE_LOCK(flags);
1911 	LCACHE_SLEEP_COND(log->free_wait, (bp = log->lbuf_free), flags);
1912 	log->lbuf_free = bp->l_freelist;
1913 	LCACHE_UNLOCK(flags);
1914 
1915 	bp->l_flag = 0;
1916 
1917 	bp->l_wqnext = NULL;
1918 	bp->l_freelist = NULL;
1919 
1920 	bp->l_pn = pn;
1921 	bp->l_blkno = log->base + (pn << (L2LOGPSIZE - log->l2bsize));
1922 	bp->l_ceor = 0;
1923 
1924 	return bp;
1925 }
1926 
1927 
1928 /*
1929  *	lbmFree()
1930  *
1931  * release a log buffer to freelist
1932  */
1933 static void lbmFree(struct lbuf * bp)
1934 {
1935 	unsigned long flags;
1936 
1937 	LCACHE_LOCK(flags);
1938 
1939 	lbmfree(bp);
1940 
1941 	LCACHE_UNLOCK(flags);
1942 }
1943 
1944 static void lbmfree(struct lbuf * bp)
1945 {
1946 	struct jfs_log *log = bp->l_log;
1947 
1948 	assert(bp->l_wqnext == NULL);
1949 
1950 	/*
1951 	 * return the buffer to head of freelist
1952 	 */
1953 	bp->l_freelist = log->lbuf_free;
1954 	log->lbuf_free = bp;
1955 
1956 	wake_up(&log->free_wait);
1957 	return;
1958 }
1959 
1960 
1961 /*
1962  * NAME:	lbmRedrive
1963  *
1964  * FUNCTION:	add a log buffer to the the log redrive list
1965  *
1966  * PARAMETER:
1967  *     bp	- log buffer
1968  *
1969  * NOTES:
1970  *	Takes log_redrive_lock.
1971  */
1972 static inline void lbmRedrive(struct lbuf *bp)
1973 {
1974 	unsigned long flags;
1975 
1976 	spin_lock_irqsave(&log_redrive_lock, flags);
1977 	bp->l_redrive_next = log_redrive_list;
1978 	log_redrive_list = bp;
1979 	spin_unlock_irqrestore(&log_redrive_lock, flags);
1980 
1981 	wake_up_process(jfsIOthread);
1982 }
1983 
1984 
1985 /*
1986  *	lbmRead()
1987  */
1988 static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
1989 {
1990 	struct bio *bio;
1991 	struct lbuf *bp;
1992 
1993 	/*
1994 	 * allocate a log buffer
1995 	 */
1996 	*bpp = bp = lbmAllocate(log, pn);
1997 	jfs_info("lbmRead: bp:0x%p pn:0x%x", bp, pn);
1998 
1999 	bp->l_flag |= lbmREAD;
2000 
2001 	bio = bio_alloc(GFP_NOFS, 1);
2002 
2003 	bio->bi_sector = bp->l_blkno << (log->l2bsize - 9);
2004 	bio->bi_bdev = log->bdev;
2005 	bio->bi_io_vec[0].bv_page = bp->l_page;
2006 	bio->bi_io_vec[0].bv_len = LOGPSIZE;
2007 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
2008 
2009 	bio->bi_vcnt = 1;
2010 	bio->bi_idx = 0;
2011 	bio->bi_size = LOGPSIZE;
2012 
2013 	bio->bi_end_io = lbmIODone;
2014 	bio->bi_private = bp;
2015 	submit_bio(READ_SYNC, bio);
2016 
2017 	wait_event(bp->l_ioevent, (bp->l_flag != lbmREAD));
2018 
2019 	return 0;
2020 }
2021 
2022 
2023 /*
2024  *	lbmWrite()
2025  *
2026  * buffer at head of pageout queue stays after completion of
2027  * partial-page pageout and redriven by explicit initiation of
2028  * pageout by caller until full-page pageout is completed and
2029  * released.
2030  *
2031  * device driver i/o done redrives pageout of new buffer at
2032  * head of pageout queue when current buffer at head of pageout
2033  * queue is released at the completion of its full-page pageout.
2034  *
2035  * LOGGC_LOCK() serializes lbmWrite() by lmNextPage() and lmGroupCommit().
2036  * LCACHE_LOCK() serializes xflag between lbmWrite() and lbmIODone()
2037  */
2038 static void lbmWrite(struct jfs_log * log, struct lbuf * bp, int flag,
2039 		     int cant_block)
2040 {
2041 	struct lbuf *tail;
2042 	unsigned long flags;
2043 
2044 	jfs_info("lbmWrite: bp:0x%p flag:0x%x pn:0x%x", bp, flag, bp->l_pn);
2045 
2046 	/* map the logical block address to physical block address */
2047 	bp->l_blkno =
2048 	    log->base + (bp->l_pn << (L2LOGPSIZE - log->l2bsize));
2049 
2050 	LCACHE_LOCK(flags);		/* disable+lock */
2051 
2052 	/*
2053 	 * initialize buffer for device driver
2054 	 */
2055 	bp->l_flag = flag;
2056 
2057 	/*
2058 	 *      insert bp at tail of write queue associated with log
2059 	 *
2060 	 * (request is either for bp already/currently at head of queue
2061 	 * or new bp to be inserted at tail)
2062 	 */
2063 	tail = log->wqueue;
2064 
2065 	/* is buffer not already on write queue ? */
2066 	if (bp->l_wqnext == NULL) {
2067 		/* insert at tail of wqueue */
2068 		if (tail == NULL) {
2069 			log->wqueue = bp;
2070 			bp->l_wqnext = bp;
2071 		} else {
2072 			log->wqueue = bp;
2073 			bp->l_wqnext = tail->l_wqnext;
2074 			tail->l_wqnext = bp;
2075 		}
2076 
2077 		tail = bp;
2078 	}
2079 
2080 	/* is buffer at head of wqueue and for write ? */
2081 	if ((bp != tail->l_wqnext) || !(flag & lbmWRITE)) {
2082 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2083 		return;
2084 	}
2085 
2086 	LCACHE_UNLOCK(flags);	/* unlock+enable */
2087 
2088 	if (cant_block)
2089 		lbmRedrive(bp);
2090 	else if (flag & lbmSYNC)
2091 		lbmStartIO(bp);
2092 	else {
2093 		LOGGC_UNLOCK(log);
2094 		lbmStartIO(bp);
2095 		LOGGC_LOCK(log);
2096 	}
2097 }
2098 
2099 
2100 /*
2101  *	lbmDirectWrite()
2102  *
2103  * initiate pageout bypassing write queue for sidestream
2104  * (e.g., log superblock) write;
2105  */
2106 static void lbmDirectWrite(struct jfs_log * log, struct lbuf * bp, int flag)
2107 {
2108 	jfs_info("lbmDirectWrite: bp:0x%p flag:0x%x pn:0x%x",
2109 		 bp, flag, bp->l_pn);
2110 
2111 	/*
2112 	 * initialize buffer for device driver
2113 	 */
2114 	bp->l_flag = flag | lbmDIRECT;
2115 
2116 	/* map the logical block address to physical block address */
2117 	bp->l_blkno =
2118 	    log->base + (bp->l_pn << (L2LOGPSIZE - log->l2bsize));
2119 
2120 	/*
2121 	 *      initiate pageout of the page
2122 	 */
2123 	lbmStartIO(bp);
2124 }
2125 
2126 
2127 /*
2128  * NAME:	lbmStartIO()
2129  *
2130  * FUNCTION:	Interface to DD strategy routine
2131  *
2132  * RETURN:      none
2133  *
2134  * serialization: LCACHE_LOCK() is NOT held during log i/o;
2135  */
2136 static void lbmStartIO(struct lbuf * bp)
2137 {
2138 	struct bio *bio;
2139 	struct jfs_log *log = bp->l_log;
2140 
2141 	jfs_info("lbmStartIO\n");
2142 
2143 	bio = bio_alloc(GFP_NOFS, 1);
2144 	bio->bi_sector = bp->l_blkno << (log->l2bsize - 9);
2145 	bio->bi_bdev = log->bdev;
2146 	bio->bi_io_vec[0].bv_page = bp->l_page;
2147 	bio->bi_io_vec[0].bv_len = LOGPSIZE;
2148 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
2149 
2150 	bio->bi_vcnt = 1;
2151 	bio->bi_idx = 0;
2152 	bio->bi_size = LOGPSIZE;
2153 
2154 	bio->bi_end_io = lbmIODone;
2155 	bio->bi_private = bp;
2156 
2157 	/* check if journaling to disk has been disabled */
2158 	if (log->no_integrity) {
2159 		bio->bi_size = 0;
2160 		lbmIODone(bio, 0, 0);
2161 	} else {
2162 		submit_bio(WRITE_SYNC, bio);
2163 		INCREMENT(lmStat.submitted);
2164 	}
2165 }
2166 
2167 
2168 /*
2169  *	lbmIOWait()
2170  */
2171 static int lbmIOWait(struct lbuf * bp, int flag)
2172 {
2173 	unsigned long flags;
2174 	int rc = 0;
2175 
2176 	jfs_info("lbmIOWait1: bp:0x%p flag:0x%x:0x%x", bp, bp->l_flag, flag);
2177 
2178 	LCACHE_LOCK(flags);		/* disable+lock */
2179 
2180 	LCACHE_SLEEP_COND(bp->l_ioevent, (bp->l_flag & lbmDONE), flags);
2181 
2182 	rc = (bp->l_flag & lbmERROR) ? -EIO : 0;
2183 
2184 	if (flag & lbmFREE)
2185 		lbmfree(bp);
2186 
2187 	LCACHE_UNLOCK(flags);	/* unlock+enable */
2188 
2189 	jfs_info("lbmIOWait2: bp:0x%p flag:0x%x:0x%x", bp, bp->l_flag, flag);
2190 	return rc;
2191 }
2192 
2193 /*
2194  *	lbmIODone()
2195  *
2196  * executed at INTIODONE level
2197  */
2198 static int lbmIODone(struct bio *bio, unsigned int bytes_done, int error)
2199 {
2200 	struct lbuf *bp = bio->bi_private;
2201 	struct lbuf *nextbp, *tail;
2202 	struct jfs_log *log;
2203 	unsigned long flags;
2204 
2205 	if (bio->bi_size)
2206 		return 1;
2207 
2208 	/*
2209 	 * get back jfs buffer bound to the i/o buffer
2210 	 */
2211 	jfs_info("lbmIODone: bp:0x%p flag:0x%x", bp, bp->l_flag);
2212 
2213 	LCACHE_LOCK(flags);		/* disable+lock */
2214 
2215 	bp->l_flag |= lbmDONE;
2216 
2217 	if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
2218 		bp->l_flag |= lbmERROR;
2219 
2220 		jfs_err("lbmIODone: I/O error in JFS log");
2221 	}
2222 
2223 	bio_put(bio);
2224 
2225 	/*
2226 	 *      pagein completion
2227 	 */
2228 	if (bp->l_flag & lbmREAD) {
2229 		bp->l_flag &= ~lbmREAD;
2230 
2231 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2232 
2233 		/* wakeup I/O initiator */
2234 		LCACHE_WAKEUP(&bp->l_ioevent);
2235 
2236 		return 0;
2237 	}
2238 
2239 	/*
2240 	 *      pageout completion
2241 	 *
2242 	 * the bp at the head of write queue has completed pageout.
2243 	 *
2244 	 * if single-commit/full-page pageout, remove the current buffer
2245 	 * from head of pageout queue, and redrive pageout with
2246 	 * the new buffer at head of pageout queue;
2247 	 * otherwise, the partial-page pageout buffer stays at
2248 	 * the head of pageout queue to be redriven for pageout
2249 	 * by lmGroupCommit() until full-page pageout is completed.
2250 	 */
2251 	bp->l_flag &= ~lbmWRITE;
2252 	INCREMENT(lmStat.pagedone);
2253 
2254 	/* update committed lsn */
2255 	log = bp->l_log;
2256 	log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor;
2257 
2258 	if (bp->l_flag & lbmDIRECT) {
2259 		LCACHE_WAKEUP(&bp->l_ioevent);
2260 		LCACHE_UNLOCK(flags);
2261 		return 0;
2262 	}
2263 
2264 	tail = log->wqueue;
2265 
2266 	/* single element queue */
2267 	if (bp == tail) {
2268 		/* remove head buffer of full-page pageout
2269 		 * from log device write queue
2270 		 */
2271 		if (bp->l_flag & lbmRELEASE) {
2272 			log->wqueue = NULL;
2273 			bp->l_wqnext = NULL;
2274 		}
2275 	}
2276 	/* multi element queue */
2277 	else {
2278 		/* remove head buffer of full-page pageout
2279 		 * from log device write queue
2280 		 */
2281 		if (bp->l_flag & lbmRELEASE) {
2282 			nextbp = tail->l_wqnext = bp->l_wqnext;
2283 			bp->l_wqnext = NULL;
2284 
2285 			/*
2286 			 * redrive pageout of next page at head of write queue:
2287 			 * redrive next page without any bound tblk
2288 			 * (i.e., page w/o any COMMIT records), or
2289 			 * first page of new group commit which has been
2290 			 * queued after current page (subsequent pageout
2291 			 * is performed synchronously, except page without
2292 			 * any COMMITs) by lmGroupCommit() as indicated
2293 			 * by lbmWRITE flag;
2294 			 */
2295 			if (nextbp->l_flag & lbmWRITE) {
2296 				/*
2297 				 * We can't do the I/O at interrupt time.
2298 				 * The jfsIO thread can do it
2299 				 */
2300 				lbmRedrive(nextbp);
2301 			}
2302 		}
2303 	}
2304 
2305 	/*
2306 	 *      synchronous pageout:
2307 	 *
2308 	 * buffer has not necessarily been removed from write queue
2309 	 * (e.g., synchronous write of partial-page with COMMIT):
2310 	 * leave buffer for i/o initiator to dispose
2311 	 */
2312 	if (bp->l_flag & lbmSYNC) {
2313 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2314 
2315 		/* wakeup I/O initiator */
2316 		LCACHE_WAKEUP(&bp->l_ioevent);
2317 	}
2318 
2319 	/*
2320 	 *      Group Commit pageout:
2321 	 */
2322 	else if (bp->l_flag & lbmGC) {
2323 		LCACHE_UNLOCK(flags);
2324 		lmPostGC(bp);
2325 	}
2326 
2327 	/*
2328 	 *      asynchronous pageout:
2329 	 *
2330 	 * buffer must have been removed from write queue:
2331 	 * insert buffer at head of freelist where it can be recycled
2332 	 */
2333 	else {
2334 		assert(bp->l_flag & lbmRELEASE);
2335 		assert(bp->l_flag & lbmFREE);
2336 		lbmfree(bp);
2337 
2338 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2339 	}
2340 
2341 	return 0;
2342 }
2343 
2344 int jfsIOWait(void *arg)
2345 {
2346 	struct lbuf *bp;
2347 
2348 	do {
2349 		spin_lock_irq(&log_redrive_lock);
2350 		while ((bp = log_redrive_list) != 0) {
2351 			log_redrive_list = bp->l_redrive_next;
2352 			bp->l_redrive_next = NULL;
2353 			spin_unlock_irq(&log_redrive_lock);
2354 			lbmStartIO(bp);
2355 			spin_lock_irq(&log_redrive_lock);
2356 		}
2357 		spin_unlock_irq(&log_redrive_lock);
2358 
2359 		if (freezing(current)) {
2360 			refrigerator();
2361 		} else {
2362 			set_current_state(TASK_INTERRUPTIBLE);
2363 			schedule();
2364 			current->state = TASK_RUNNING;
2365 		}
2366 	} while (!kthread_should_stop());
2367 
2368 	jfs_info("jfsIOWait being killed!");
2369 	return 0;
2370 }
2371 
2372 /*
2373  * NAME:	lmLogFormat()/jfs_logform()
2374  *
2375  * FUNCTION:	format file system log
2376  *
2377  * PARAMETERS:
2378  *      log	- volume log
2379  *	logAddress - start address of log space in FS block
2380  *	logSize	- length of log space in FS block;
2381  *
2382  * RETURN:	0	- success
2383  *		-EIO	- i/o error
2384  *
2385  * XXX: We're synchronously writing one page at a time.  This needs to
2386  *	be improved by writing multiple pages at once.
2387  */
2388 int lmLogFormat(struct jfs_log *log, s64 logAddress, int logSize)
2389 {
2390 	int rc = -EIO;
2391 	struct jfs_sb_info *sbi;
2392 	struct logsuper *logsuper;
2393 	struct logpage *lp;
2394 	int lspn;		/* log sequence page number */
2395 	struct lrd *lrd_ptr;
2396 	int npages = 0;
2397 	struct lbuf *bp;
2398 
2399 	jfs_info("lmLogFormat: logAddress:%Ld logSize:%d",
2400 		 (long long)logAddress, logSize);
2401 
2402 	sbi = list_entry(log->sb_list.next, struct jfs_sb_info, log_list);
2403 
2404 	/* allocate a log buffer */
2405 	bp = lbmAllocate(log, 1);
2406 
2407 	npages = logSize >> sbi->l2nbperpage;
2408 
2409 	/*
2410 	 *      log space:
2411 	 *
2412 	 * page 0 - reserved;
2413 	 * page 1 - log superblock;
2414 	 * page 2 - log data page: A SYNC log record is written
2415 	 *          into this page at logform time;
2416 	 * pages 3-N - log data page: set to empty log data pages;
2417 	 */
2418 	/*
2419 	 *      init log superblock: log page 1
2420 	 */
2421 	logsuper = (struct logsuper *) bp->l_ldata;
2422 
2423 	logsuper->magic = cpu_to_le32(LOGMAGIC);
2424 	logsuper->version = cpu_to_le32(LOGVERSION);
2425 	logsuper->state = cpu_to_le32(LOGREDONE);
2426 	logsuper->flag = cpu_to_le32(sbi->mntflag);	/* ? */
2427 	logsuper->size = cpu_to_le32(npages);
2428 	logsuper->bsize = cpu_to_le32(sbi->bsize);
2429 	logsuper->l2bsize = cpu_to_le32(sbi->l2bsize);
2430 	logsuper->end = cpu_to_le32(2 * LOGPSIZE + LOGPHDRSIZE + LOGRDSIZE);
2431 
2432 	bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
2433 	bp->l_blkno = logAddress + sbi->nbperpage;
2434 	lbmStartIO(bp);
2435 	if ((rc = lbmIOWait(bp, 0)))
2436 		goto exit;
2437 
2438 	/*
2439 	 *      init pages 2 to npages-1 as log data pages:
2440 	 *
2441 	 * log page sequence number (lpsn) initialization:
2442 	 *
2443 	 * pn:   0     1     2     3                 n-1
2444 	 *       +-----+-----+=====+=====+===.....===+=====+
2445 	 * lspn:             N-1   0     1           N-2
2446 	 *                   <--- N page circular file ---->
2447 	 *
2448 	 * the N (= npages-2) data pages of the log is maintained as
2449 	 * a circular file for the log records;
2450 	 * lpsn grows by 1 monotonically as each log page is written
2451 	 * to the circular file of the log;
2452 	 * and setLogpage() will not reset the page number even if
2453 	 * the eor is equal to LOGPHDRSIZE. In order for binary search
2454 	 * still work in find log end process, we have to simulate the
2455 	 * log wrap situation at the log format time.
2456 	 * The 1st log page written will have the highest lpsn. Then
2457 	 * the succeeding log pages will have ascending order of
2458 	 * the lspn starting from 0, ... (N-2)
2459 	 */
2460 	lp = (struct logpage *) bp->l_ldata;
2461 	/*
2462 	 * initialize 1st log page to be written: lpsn = N - 1,
2463 	 * write a SYNCPT log record is written to this page
2464 	 */
2465 	lp->h.page = lp->t.page = cpu_to_le32(npages - 3);
2466 	lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE + LOGRDSIZE);
2467 
2468 	lrd_ptr = (struct lrd *) &lp->data;
2469 	lrd_ptr->logtid = 0;
2470 	lrd_ptr->backchain = 0;
2471 	lrd_ptr->type = cpu_to_le16(LOG_SYNCPT);
2472 	lrd_ptr->length = 0;
2473 	lrd_ptr->log.syncpt.sync = 0;
2474 
2475 	bp->l_blkno += sbi->nbperpage;
2476 	bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
2477 	lbmStartIO(bp);
2478 	if ((rc = lbmIOWait(bp, 0)))
2479 		goto exit;
2480 
2481 	/*
2482 	 *      initialize succeeding log pages: lpsn = 0, 1, ..., (N-2)
2483 	 */
2484 	for (lspn = 0; lspn < npages - 3; lspn++) {
2485 		lp->h.page = lp->t.page = cpu_to_le32(lspn);
2486 		lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE);
2487 
2488 		bp->l_blkno += sbi->nbperpage;
2489 		bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
2490 		lbmStartIO(bp);
2491 		if ((rc = lbmIOWait(bp, 0)))
2492 			goto exit;
2493 	}
2494 
2495 	rc = 0;
2496 exit:
2497 	/*
2498 	 *      finalize log
2499 	 */
2500 	/* release the buffer */
2501 	lbmFree(bp);
2502 
2503 	return rc;
2504 }
2505 
2506 #ifdef CONFIG_JFS_STATISTICS
2507 int jfs_lmstats_read(char *buffer, char **start, off_t offset, int length,
2508 		      int *eof, void *data)
2509 {
2510 	int len = 0;
2511 	off_t begin;
2512 
2513 	len += sprintf(buffer,
2514 		       "JFS Logmgr stats\n"
2515 		       "================\n"
2516 		       "commits = %d\n"
2517 		       "writes submitted = %d\n"
2518 		       "writes completed = %d\n"
2519 		       "full pages submitted = %d\n"
2520 		       "partial pages submitted = %d\n",
2521 		       lmStat.commit,
2522 		       lmStat.submitted,
2523 		       lmStat.pagedone,
2524 		       lmStat.full_page,
2525 		       lmStat.partial_page);
2526 
2527 	begin = offset;
2528 	*start = buffer + begin;
2529 	len -= begin;
2530 
2531 	if (len > length)
2532 		len = length;
2533 	else
2534 		*eof = 1;
2535 
2536 	if (len < 0)
2537 		len = 0;
2538 
2539 	return len;
2540 }
2541 #endif /* CONFIG_JFS_STATISTICS */
2542