xref: /openbmc/linux/fs/jfs/jfs_logmgr.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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/delay.h>
71 #include <linux/mutex.h>
72 #include "jfs_incore.h"
73 #include "jfs_filsys.h"
74 #include "jfs_metapage.h"
75 #include "jfs_superblock.h"
76 #include "jfs_txnmgr.h"
77 #include "jfs_debug.h"
78 
79 
80 /*
81  * lbuf's ready to be redriven.  Protected by log_redrive_lock (jfsIO thread)
82  */
83 static struct lbuf *log_redrive_list;
84 static DEFINE_SPINLOCK(log_redrive_lock);
85 
86 
87 /*
88  *	log read/write serialization (per log)
89  */
90 #define LOG_LOCK_INIT(log)	mutex_init(&(log)->loglock)
91 #define LOG_LOCK(log)		mutex_lock(&((log)->loglock))
92 #define LOG_UNLOCK(log)		mutex_unlock(&((log)->loglock))
93 
94 
95 /*
96  *	log group commit serialization (per log)
97  */
98 
99 #define LOGGC_LOCK_INIT(log)	spin_lock_init(&(log)->gclock)
100 #define LOGGC_LOCK(log)		spin_lock_irq(&(log)->gclock)
101 #define LOGGC_UNLOCK(log)	spin_unlock_irq(&(log)->gclock)
102 #define LOGGC_WAKEUP(tblk)	wake_up_all(&(tblk)->gcwait)
103 
104 /*
105  *	log sync serialization (per log)
106  */
107 #define	LOGSYNC_DELTA(logsize)		min((logsize)/8, 128*LOGPSIZE)
108 #define	LOGSYNC_BARRIER(logsize)	((logsize)/4)
109 /*
110 #define	LOGSYNC_DELTA(logsize)		min((logsize)/4, 256*LOGPSIZE)
111 #define	LOGSYNC_BARRIER(logsize)	((logsize)/2)
112 */
113 
114 
115 /*
116  *	log buffer cache synchronization
117  */
118 static DEFINE_SPINLOCK(jfsLCacheLock);
119 
120 #define	LCACHE_LOCK(flags)	spin_lock_irqsave(&jfsLCacheLock, flags)
121 #define	LCACHE_UNLOCK(flags)	spin_unlock_irqrestore(&jfsLCacheLock, flags)
122 
123 /*
124  * See __SLEEP_COND in jfs_locks.h
125  */
126 #define LCACHE_SLEEP_COND(wq, cond, flags)	\
127 do {						\
128 	if (cond)				\
129 		break;				\
130 	__SLEEP_COND(wq, cond, LCACHE_LOCK(flags), LCACHE_UNLOCK(flags)); \
131 } while (0)
132 
133 #define	LCACHE_WAKEUP(event)	wake_up(event)
134 
135 
136 /*
137  *	lbuf buffer cache (lCache) control
138  */
139 /* log buffer manager pageout control (cumulative, inclusive) */
140 #define	lbmREAD		0x0001
141 #define	lbmWRITE	0x0002	/* enqueue at tail of write queue;
142 				 * init pageout if at head of queue;
143 				 */
144 #define	lbmRELEASE	0x0004	/* remove from write queue
145 				 * at completion of pageout;
146 				 * do not free/recycle it yet:
147 				 * caller will free it;
148 				 */
149 #define	lbmSYNC		0x0008	/* do not return to freelist
150 				 * when removed from write queue;
151 				 */
152 #define lbmFREE		0x0010	/* return to freelist
153 				 * at completion of pageout;
154 				 * the buffer may be recycled;
155 				 */
156 #define	lbmDONE		0x0020
157 #define	lbmERROR	0x0040
158 #define lbmGC		0x0080	/* lbmIODone to perform post-GC processing
159 				 * of log page
160 				 */
161 #define lbmDIRECT	0x0100
162 
163 /*
164  * Global list of active external journals
165  */
166 static LIST_HEAD(jfs_external_logs);
167 static struct jfs_log *dummy_log = NULL;
168 static DEFINE_MUTEX(jfs_log_mutex);
169 
170 /*
171  * forward references
172  */
173 static int lmWriteRecord(struct jfs_log * log, struct tblock * tblk,
174 			 struct lrd * lrd, struct tlock * tlck);
175 
176 static int lmNextPage(struct jfs_log * log);
177 static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
178 			   int activate);
179 
180 static int open_inline_log(struct super_block *sb);
181 static int open_dummy_log(struct super_block *sb);
182 static int lbmLogInit(struct jfs_log * log);
183 static void lbmLogShutdown(struct jfs_log * log);
184 static struct lbuf *lbmAllocate(struct jfs_log * log, int);
185 static void lbmFree(struct lbuf * bp);
186 static void lbmfree(struct lbuf * bp);
187 static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp);
188 static void lbmWrite(struct jfs_log * log, struct lbuf * bp, int flag, int cant_block);
189 static void lbmDirectWrite(struct jfs_log * log, struct lbuf * bp, int flag);
190 static int lbmIOWait(struct lbuf * bp, int flag);
191 static bio_end_io_t lbmIODone;
192 static void lbmStartIO(struct lbuf * bp);
193 static void lmGCwrite(struct jfs_log * log, int cant_block);
194 static int lmLogSync(struct jfs_log * log, int hard_sync);
195 
196 
197 
198 /*
199  *	statistics
200  */
201 #ifdef CONFIG_JFS_STATISTICS
202 static struct lmStat {
203 	uint commit;		/* # of commit */
204 	uint pagedone;		/* # of page written */
205 	uint submitted;		/* # of pages submitted */
206 	uint full_page;		/* # of full pages submitted */
207 	uint partial_page;	/* # of partial pages submitted */
208 } lmStat;
209 #endif
210 
211 
212 /*
213  * NAME:	lmLog()
214  *
215  * FUNCTION:	write a log record;
216  *
217  * PARAMETER:
218  *
219  * RETURN:	lsn - offset to the next log record to write (end-of-log);
220  *		-1  - error;
221  *
222  * note: todo: log error handler
223  */
224 int lmLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
225 	  struct tlock * tlck)
226 {
227 	int lsn;
228 	int diffp, difft;
229 	struct metapage *mp = NULL;
230 	unsigned long flags;
231 
232 	jfs_info("lmLog: log:0x%p tblk:0x%p, lrd:0x%p tlck:0x%p",
233 		 log, tblk, lrd, tlck);
234 
235 	LOG_LOCK(log);
236 
237 	/* log by (out-of-transaction) JFS ? */
238 	if (tblk == NULL)
239 		goto writeRecord;
240 
241 	/* log from page ? */
242 	if (tlck == NULL ||
243 	    tlck->type & tlckBTROOT || (mp = tlck->mp) == NULL)
244 		goto writeRecord;
245 
246 	/*
247 	 *      initialize/update page/transaction recovery lsn
248 	 */
249 	lsn = log->lsn;
250 
251 	LOGSYNC_LOCK(log, flags);
252 
253 	/*
254 	 * initialize page lsn if first log write of the page
255 	 */
256 	if (mp->lsn == 0) {
257 		mp->log = log;
258 		mp->lsn = lsn;
259 		log->count++;
260 
261 		/* insert page at tail of logsynclist */
262 		list_add_tail(&mp->synclist, &log->synclist);
263 	}
264 
265 	/*
266 	 *      initialize/update lsn of tblock of the page
267 	 *
268 	 * transaction inherits oldest lsn of pages associated
269 	 * with allocation/deallocation of resources (their
270 	 * log records are used to reconstruct allocation map
271 	 * at recovery time: inode for inode allocation map,
272 	 * B+-tree index of extent descriptors for block
273 	 * allocation map);
274 	 * allocation map pages inherit transaction lsn at
275 	 * commit time to allow forwarding log syncpt past log
276 	 * records associated with allocation/deallocation of
277 	 * resources only after persistent map of these map pages
278 	 * have been updated and propagated to home.
279 	 */
280 	/*
281 	 * initialize transaction lsn:
282 	 */
283 	if (tblk->lsn == 0) {
284 		/* inherit lsn of its first page logged */
285 		tblk->lsn = mp->lsn;
286 		log->count++;
287 
288 		/* insert tblock after the page on logsynclist */
289 		list_add(&tblk->synclist, &mp->synclist);
290 	}
291 	/*
292 	 * update transaction lsn:
293 	 */
294 	else {
295 		/* inherit oldest/smallest lsn of page */
296 		logdiff(diffp, mp->lsn, log);
297 		logdiff(difft, tblk->lsn, log);
298 		if (diffp < difft) {
299 			/* update tblock lsn with page lsn */
300 			tblk->lsn = mp->lsn;
301 
302 			/* move tblock after page on logsynclist */
303 			list_move(&tblk->synclist, &mp->synclist);
304 		}
305 	}
306 
307 	LOGSYNC_UNLOCK(log, flags);
308 
309 	/*
310 	 *      write the log record
311 	 */
312       writeRecord:
313 	lsn = lmWriteRecord(log, tblk, lrd, tlck);
314 
315 	/*
316 	 * forward log syncpt if log reached next syncpt trigger
317 	 */
318 	logdiff(diffp, lsn, log);
319 	if (diffp >= log->nextsync)
320 		lsn = lmLogSync(log, 0);
321 
322 	/* update end-of-log lsn */
323 	log->lsn = lsn;
324 
325 	LOG_UNLOCK(log);
326 
327 	/* return end-of-log address */
328 	return lsn;
329 }
330 
331 /*
332  * NAME:	lmWriteRecord()
333  *
334  * FUNCTION:	move the log record to current log page
335  *
336  * PARAMETER:	cd	- commit descriptor
337  *
338  * RETURN:	end-of-log address
339  *
340  * serialization: LOG_LOCK() held on entry/exit
341  */
342 static int
343 lmWriteRecord(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
344 	      struct tlock * tlck)
345 {
346 	int lsn = 0;		/* end-of-log address */
347 	struct lbuf *bp;	/* dst log page buffer */
348 	struct logpage *lp;	/* dst log page */
349 	caddr_t dst;		/* destination address in log page */
350 	int dstoffset;		/* end-of-log offset in log page */
351 	int freespace;		/* free space in log page */
352 	caddr_t p;		/* src meta-data page */
353 	caddr_t src;
354 	int srclen;
355 	int nbytes;		/* number of bytes to move */
356 	int i;
357 	int len;
358 	struct linelock *linelock;
359 	struct lv *lv;
360 	struct lvd *lvd;
361 	int l2linesize;
362 
363 	len = 0;
364 
365 	/* retrieve destination log page to write */
366 	bp = (struct lbuf *) log->bp;
367 	lp = (struct logpage *) bp->l_ldata;
368 	dstoffset = log->eor;
369 
370 	/* any log data to write ? */
371 	if (tlck == NULL)
372 		goto moveLrd;
373 
374 	/*
375 	 *      move log record data
376 	 */
377 	/* retrieve source meta-data page to log */
378 	if (tlck->flag & tlckPAGELOCK) {
379 		p = (caddr_t) (tlck->mp->data);
380 		linelock = (struct linelock *) & tlck->lock;
381 	}
382 	/* retrieve source in-memory inode to log */
383 	else if (tlck->flag & tlckINODELOCK) {
384 		if (tlck->type & tlckDTREE)
385 			p = (caddr_t) &JFS_IP(tlck->ip)->i_dtroot;
386 		else
387 			p = (caddr_t) &JFS_IP(tlck->ip)->i_xtroot;
388 		linelock = (struct linelock *) & tlck->lock;
389 	}
390 #ifdef	_JFS_WIP
391 	else if (tlck->flag & tlckINLINELOCK) {
392 
393 		inlinelock = (struct inlinelock *) & tlck;
394 		p = (caddr_t) & inlinelock->pxd;
395 		linelock = (struct linelock *) & tlck;
396 	}
397 #endif				/* _JFS_WIP */
398 	else {
399 		jfs_err("lmWriteRecord: UFO tlck:0x%p", tlck);
400 		return 0;	/* Probably should trap */
401 	}
402 	l2linesize = linelock->l2linesize;
403 
404       moveData:
405 	ASSERT(linelock->index <= linelock->maxcnt);
406 
407 	lv = linelock->lv;
408 	for (i = 0; i < linelock->index; i++, lv++) {
409 		if (lv->length == 0)
410 			continue;
411 
412 		/* is page full ? */
413 		if (dstoffset >= LOGPSIZE - LOGPTLRSIZE) {
414 			/* page become full: move on to next page */
415 			lmNextPage(log);
416 
417 			bp = log->bp;
418 			lp = (struct logpage *) bp->l_ldata;
419 			dstoffset = LOGPHDRSIZE;
420 		}
421 
422 		/*
423 		 * move log vector data
424 		 */
425 		src = (u8 *) p + (lv->offset << l2linesize);
426 		srclen = lv->length << l2linesize;
427 		len += srclen;
428 		while (srclen > 0) {
429 			freespace = (LOGPSIZE - LOGPTLRSIZE) - dstoffset;
430 			nbytes = min(freespace, srclen);
431 			dst = (caddr_t) lp + dstoffset;
432 			memcpy(dst, src, nbytes);
433 			dstoffset += nbytes;
434 
435 			/* is page not full ? */
436 			if (dstoffset < LOGPSIZE - LOGPTLRSIZE)
437 				break;
438 
439 			/* page become full: move on to next page */
440 			lmNextPage(log);
441 
442 			bp = (struct lbuf *) log->bp;
443 			lp = (struct logpage *) bp->l_ldata;
444 			dstoffset = LOGPHDRSIZE;
445 
446 			srclen -= nbytes;
447 			src += nbytes;
448 		}
449 
450 		/*
451 		 * move log vector descriptor
452 		 */
453 		len += 4;
454 		lvd = (struct lvd *) ((caddr_t) lp + dstoffset);
455 		lvd->offset = cpu_to_le16(lv->offset);
456 		lvd->length = cpu_to_le16(lv->length);
457 		dstoffset += 4;
458 		jfs_info("lmWriteRecord: lv offset:%d length:%d",
459 			 lv->offset, lv->length);
460 	}
461 
462 	if ((i = linelock->next)) {
463 		linelock = (struct linelock *) lid_to_tlock(i);
464 		goto moveData;
465 	}
466 
467 	/*
468 	 *      move log record descriptor
469 	 */
470       moveLrd:
471 	lrd->length = cpu_to_le16(len);
472 
473 	src = (caddr_t) lrd;
474 	srclen = LOGRDSIZE;
475 
476 	while (srclen > 0) {
477 		freespace = (LOGPSIZE - LOGPTLRSIZE) - dstoffset;
478 		nbytes = min(freespace, srclen);
479 		dst = (caddr_t) lp + dstoffset;
480 		memcpy(dst, src, nbytes);
481 
482 		dstoffset += nbytes;
483 		srclen -= nbytes;
484 
485 		/* are there more to move than freespace of page ? */
486 		if (srclen)
487 			goto pageFull;
488 
489 		/*
490 		 * end of log record descriptor
491 		 */
492 
493 		/* update last log record eor */
494 		log->eor = dstoffset;
495 		bp->l_eor = dstoffset;
496 		lsn = (log->page << L2LOGPSIZE) + dstoffset;
497 
498 		if (lrd->type & cpu_to_le16(LOG_COMMIT)) {
499 			tblk->clsn = lsn;
500 			jfs_info("wr: tclsn:0x%x, beor:0x%x", tblk->clsn,
501 				 bp->l_eor);
502 
503 			INCREMENT(lmStat.commit);	/* # of commit */
504 
505 			/*
506 			 * enqueue tblock for group commit:
507 			 *
508 			 * enqueue tblock of non-trivial/synchronous COMMIT
509 			 * at tail of group commit queue
510 			 * (trivial/asynchronous COMMITs are ignored by
511 			 * group commit.)
512 			 */
513 			LOGGC_LOCK(log);
514 
515 			/* init tblock gc state */
516 			tblk->flag = tblkGC_QUEUE;
517 			tblk->bp = log->bp;
518 			tblk->pn = log->page;
519 			tblk->eor = log->eor;
520 
521 			/* enqueue transaction to commit queue */
522 			list_add_tail(&tblk->cqueue, &log->cqueue);
523 
524 			LOGGC_UNLOCK(log);
525 		}
526 
527 		jfs_info("lmWriteRecord: lrd:0x%04x bp:0x%p pn:%d eor:0x%x",
528 			le16_to_cpu(lrd->type), log->bp, log->page, dstoffset);
529 
530 		/* page not full ? */
531 		if (dstoffset < LOGPSIZE - LOGPTLRSIZE)
532 			return lsn;
533 
534 	      pageFull:
535 		/* page become full: move on to next page */
536 		lmNextPage(log);
537 
538 		bp = (struct lbuf *) log->bp;
539 		lp = (struct logpage *) bp->l_ldata;
540 		dstoffset = LOGPHDRSIZE;
541 		src += nbytes;
542 	}
543 
544 	return lsn;
545 }
546 
547 
548 /*
549  * NAME:	lmNextPage()
550  *
551  * FUNCTION:	write current page and allocate next page.
552  *
553  * PARAMETER:	log
554  *
555  * RETURN:	0
556  *
557  * serialization: LOG_LOCK() held on entry/exit
558  */
559 static int lmNextPage(struct jfs_log * log)
560 {
561 	struct logpage *lp;
562 	int lspn;		/* log sequence page number */
563 	int pn;			/* current page number */
564 	struct lbuf *bp;
565 	struct lbuf *nextbp;
566 	struct tblock *tblk;
567 
568 	/* get current log page number and log sequence page number */
569 	pn = log->page;
570 	bp = log->bp;
571 	lp = (struct logpage *) bp->l_ldata;
572 	lspn = le32_to_cpu(lp->h.page);
573 
574 	LOGGC_LOCK(log);
575 
576 	/*
577 	 *      write or queue the full page at the tail of write queue
578 	 */
579 	/* get the tail tblk on commit queue */
580 	if (list_empty(&log->cqueue))
581 		tblk = NULL;
582 	else
583 		tblk = list_entry(log->cqueue.prev, struct tblock, cqueue);
584 
585 	/* every tblk who has COMMIT record on the current page,
586 	 * and has not been committed, must be on commit queue
587 	 * since tblk is queued at commit queueu at the time
588 	 * of writing its COMMIT record on the page before
589 	 * page becomes full (even though the tblk thread
590 	 * who wrote COMMIT record may have been suspended
591 	 * currently);
592 	 */
593 
594 	/* is page bound with outstanding tail tblk ? */
595 	if (tblk && tblk->pn == pn) {
596 		/* mark tblk for end-of-page */
597 		tblk->flag |= tblkGC_EOP;
598 
599 		if (log->cflag & logGC_PAGEOUT) {
600 			/* if page is not already on write queue,
601 			 * just enqueue (no lbmWRITE to prevent redrive)
602 			 * buffer to wqueue to ensure correct serial order
603 			 * of the pages since log pages will be added
604 			 * continuously
605 			 */
606 			if (bp->l_wqnext == NULL)
607 				lbmWrite(log, bp, 0, 0);
608 		} else {
609 			/*
610 			 * No current GC leader, initiate group commit
611 			 */
612 			log->cflag |= logGC_PAGEOUT;
613 			lmGCwrite(log, 0);
614 		}
615 	}
616 	/* page is not bound with outstanding tblk:
617 	 * init write or mark it to be redriven (lbmWRITE)
618 	 */
619 	else {
620 		/* finalize the page */
621 		bp->l_ceor = bp->l_eor;
622 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
623 		lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmFREE, 0);
624 	}
625 	LOGGC_UNLOCK(log);
626 
627 	/*
628 	 *      allocate/initialize next page
629 	 */
630 	/* if log wraps, the first data page of log is 2
631 	 * (0 never used, 1 is superblock).
632 	 */
633 	log->page = (pn == log->size - 1) ? 2 : pn + 1;
634 	log->eor = LOGPHDRSIZE;	/* ? valid page empty/full at logRedo() */
635 
636 	/* allocate/initialize next log page buffer */
637 	nextbp = lbmAllocate(log, log->page);
638 	nextbp->l_eor = log->eor;
639 	log->bp = nextbp;
640 
641 	/* initialize next log page */
642 	lp = (struct logpage *) nextbp->l_ldata;
643 	lp->h.page = lp->t.page = cpu_to_le32(lspn + 1);
644 	lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE);
645 
646 	return 0;
647 }
648 
649 
650 /*
651  * NAME:	lmGroupCommit()
652  *
653  * FUNCTION:	group commit
654  *	initiate pageout of the pages with COMMIT in the order of
655  *	page number - redrive pageout of the page at the head of
656  *	pageout queue until full page has been written.
657  *
658  * RETURN:
659  *
660  * NOTE:
661  *	LOGGC_LOCK serializes log group commit queue, and
662  *	transaction blocks on the commit queue.
663  *	N.B. LOG_LOCK is NOT held during lmGroupCommit().
664  */
665 int lmGroupCommit(struct jfs_log * log, struct tblock * tblk)
666 {
667 	int rc = 0;
668 
669 	LOGGC_LOCK(log);
670 
671 	/* group committed already ? */
672 	if (tblk->flag & tblkGC_COMMITTED) {
673 		if (tblk->flag & tblkGC_ERROR)
674 			rc = -EIO;
675 
676 		LOGGC_UNLOCK(log);
677 		return rc;
678 	}
679 	jfs_info("lmGroup Commit: tblk = 0x%p, gcrtc = %d", tblk, log->gcrtc);
680 
681 	if (tblk->xflag & COMMIT_LAZY)
682 		tblk->flag |= tblkGC_LAZY;
683 
684 	if ((!(log->cflag & logGC_PAGEOUT)) && (!list_empty(&log->cqueue)) &&
685 	    (!(tblk->xflag & COMMIT_LAZY) || test_bit(log_FLUSH, &log->flag)
686 	     || jfs_tlocks_low)) {
687 		/*
688 		 * No pageout in progress
689 		 *
690 		 * start group commit as its group leader.
691 		 */
692 		log->cflag |= logGC_PAGEOUT;
693 
694 		lmGCwrite(log, 0);
695 	}
696 
697 	if (tblk->xflag & COMMIT_LAZY) {
698 		/*
699 		 * Lazy transactions can leave now
700 		 */
701 		LOGGC_UNLOCK(log);
702 		return 0;
703 	}
704 
705 	/* lmGCwrite gives up LOGGC_LOCK, check again */
706 
707 	if (tblk->flag & tblkGC_COMMITTED) {
708 		if (tblk->flag & tblkGC_ERROR)
709 			rc = -EIO;
710 
711 		LOGGC_UNLOCK(log);
712 		return rc;
713 	}
714 
715 	/* upcount transaction waiting for completion
716 	 */
717 	log->gcrtc++;
718 	tblk->flag |= tblkGC_READY;
719 
720 	__SLEEP_COND(tblk->gcwait, (tblk->flag & tblkGC_COMMITTED),
721 		     LOGGC_LOCK(log), LOGGC_UNLOCK(log));
722 
723 	/* removed from commit queue */
724 	if (tblk->flag & tblkGC_ERROR)
725 		rc = -EIO;
726 
727 	LOGGC_UNLOCK(log);
728 	return rc;
729 }
730 
731 /*
732  * NAME:	lmGCwrite()
733  *
734  * FUNCTION:	group commit write
735  *	initiate write of log page, building a group of all transactions
736  *	with commit records on that page.
737  *
738  * RETURN:	None
739  *
740  * NOTE:
741  *	LOGGC_LOCK must be held by caller.
742  *	N.B. LOG_LOCK is NOT held during lmGroupCommit().
743  */
744 static void lmGCwrite(struct jfs_log * log, int cant_write)
745 {
746 	struct lbuf *bp;
747 	struct logpage *lp;
748 	int gcpn;		/* group commit page number */
749 	struct tblock *tblk;
750 	struct tblock *xtblk = NULL;
751 
752 	/*
753 	 * build the commit group of a log page
754 	 *
755 	 * scan commit queue and make a commit group of all
756 	 * transactions with COMMIT records on the same log page.
757 	 */
758 	/* get the head tblk on the commit queue */
759 	gcpn = list_entry(log->cqueue.next, struct tblock, cqueue)->pn;
760 
761 	list_for_each_entry(tblk, &log->cqueue, cqueue) {
762 		if (tblk->pn != gcpn)
763 			break;
764 
765 		xtblk = tblk;
766 
767 		/* state transition: (QUEUE, READY) -> COMMIT */
768 		tblk->flag |= tblkGC_COMMIT;
769 	}
770 	tblk = xtblk;		/* last tblk of the page */
771 
772 	/*
773 	 * pageout to commit transactions on the log page.
774 	 */
775 	bp = (struct lbuf *) tblk->bp;
776 	lp = (struct logpage *) bp->l_ldata;
777 	/* is page already full ? */
778 	if (tblk->flag & tblkGC_EOP) {
779 		/* mark page to free at end of group commit of the page */
780 		tblk->flag &= ~tblkGC_EOP;
781 		tblk->flag |= tblkGC_FREE;
782 		bp->l_ceor = bp->l_eor;
783 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
784 		lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmGC,
785 			 cant_write);
786 		INCREMENT(lmStat.full_page);
787 	}
788 	/* page is not yet full */
789 	else {
790 		bp->l_ceor = tblk->eor;	/* ? bp->l_ceor = bp->l_eor; */
791 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
792 		lbmWrite(log, bp, lbmWRITE | lbmGC, cant_write);
793 		INCREMENT(lmStat.partial_page);
794 	}
795 }
796 
797 /*
798  * NAME:	lmPostGC()
799  *
800  * FUNCTION:	group commit post-processing
801  *	Processes transactions after their commit records have been written
802  *	to disk, redriving log I/O if necessary.
803  *
804  * RETURN:	None
805  *
806  * NOTE:
807  *	This routine is called a interrupt time by lbmIODone
808  */
809 static void lmPostGC(struct lbuf * bp)
810 {
811 	unsigned long flags;
812 	struct jfs_log *log = bp->l_log;
813 	struct logpage *lp;
814 	struct tblock *tblk, *temp;
815 
816 	//LOGGC_LOCK(log);
817 	spin_lock_irqsave(&log->gclock, flags);
818 	/*
819 	 * current pageout of group commit completed.
820 	 *
821 	 * remove/wakeup transactions from commit queue who were
822 	 * group committed with the current log page
823 	 */
824 	list_for_each_entry_safe(tblk, temp, &log->cqueue, cqueue) {
825 		if (!(tblk->flag & tblkGC_COMMIT))
826 			break;
827 		/* if transaction was marked GC_COMMIT then
828 		 * it has been shipped in the current pageout
829 		 * and made it to disk - it is committed.
830 		 */
831 
832 		if (bp->l_flag & lbmERROR)
833 			tblk->flag |= tblkGC_ERROR;
834 
835 		/* remove it from the commit queue */
836 		list_del(&tblk->cqueue);
837 		tblk->flag &= ~tblkGC_QUEUE;
838 
839 		if (tblk == log->flush_tblk) {
840 			/* we can stop flushing the log now */
841 			clear_bit(log_FLUSH, &log->flag);
842 			log->flush_tblk = NULL;
843 		}
844 
845 		jfs_info("lmPostGC: tblk = 0x%p, flag = 0x%x", tblk,
846 			 tblk->flag);
847 
848 		if (!(tblk->xflag & COMMIT_FORCE))
849 			/*
850 			 * Hand tblk over to lazy commit thread
851 			 */
852 			txLazyUnlock(tblk);
853 		else {
854 			/* state transition: COMMIT -> COMMITTED */
855 			tblk->flag |= tblkGC_COMMITTED;
856 
857 			if (tblk->flag & tblkGC_READY)
858 				log->gcrtc--;
859 
860 			LOGGC_WAKEUP(tblk);
861 		}
862 
863 		/* was page full before pageout ?
864 		 * (and this is the last tblk bound with the page)
865 		 */
866 		if (tblk->flag & tblkGC_FREE)
867 			lbmFree(bp);
868 		/* did page become full after pageout ?
869 		 * (and this is the last tblk bound with the page)
870 		 */
871 		else if (tblk->flag & tblkGC_EOP) {
872 			/* finalize the page */
873 			lp = (struct logpage *) bp->l_ldata;
874 			bp->l_ceor = bp->l_eor;
875 			lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
876 			jfs_info("lmPostGC: calling lbmWrite");
877 			lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmFREE,
878 				 1);
879 		}
880 
881 	}
882 
883 	/* are there any transactions who have entered lnGroupCommit()
884 	 * (whose COMMITs are after that of the last log page written.
885 	 * They are waiting for new group commit (above at (SLEEP 1))
886 	 * or lazy transactions are on a full (queued) log page,
887 	 * select the latest ready transaction as new group leader and
888 	 * wake her up to lead her group.
889 	 */
890 	if ((!list_empty(&log->cqueue)) &&
891 	    ((log->gcrtc > 0) || (tblk->bp->l_wqnext != NULL) ||
892 	     test_bit(log_FLUSH, &log->flag) || jfs_tlocks_low))
893 		/*
894 		 * Call lmGCwrite with new group leader
895 		 */
896 		lmGCwrite(log, 1);
897 
898 	/* no transaction are ready yet (transactions are only just
899 	 * queued (GC_QUEUE) and not entered for group commit yet).
900 	 * the first transaction entering group commit
901 	 * will elect herself as new group leader.
902 	 */
903 	else
904 		log->cflag &= ~logGC_PAGEOUT;
905 
906 	//LOGGC_UNLOCK(log);
907 	spin_unlock_irqrestore(&log->gclock, flags);
908 	return;
909 }
910 
911 /*
912  * NAME:	lmLogSync()
913  *
914  * FUNCTION:	write log SYNCPT record for specified log
915  *	if new sync address is available
916  *	(normally the case if sync() is executed by back-ground
917  *	process).
918  *	calculate new value of i_nextsync which determines when
919  *	this code is called again.
920  *
921  * PARAMETERS:	log	- log structure
922  *		hard_sync - 1 to force all metadata to be written
923  *
924  * RETURN:	0
925  *
926  * serialization: LOG_LOCK() held on entry/exit
927  */
928 static int lmLogSync(struct jfs_log * log, int hard_sync)
929 {
930 	int logsize;
931 	int written;		/* written since last syncpt */
932 	int free;		/* free space left available */
933 	int delta;		/* additional delta to write normally */
934 	int more;		/* additional write granted */
935 	struct lrd lrd;
936 	int lsn;
937 	struct logsyncblk *lp;
938 	struct jfs_sb_info *sbi;
939 	unsigned long flags;
940 
941 	/* push dirty metapages out to disk */
942 	if (hard_sync)
943 		list_for_each_entry(sbi, &log->sb_list, log_list) {
944 			filemap_fdatawrite(sbi->ipbmap->i_mapping);
945 			filemap_fdatawrite(sbi->ipimap->i_mapping);
946 			filemap_fdatawrite(sbi->direct_inode->i_mapping);
947 		}
948 	else
949 		list_for_each_entry(sbi, &log->sb_list, log_list) {
950 			filemap_flush(sbi->ipbmap->i_mapping);
951 			filemap_flush(sbi->ipimap->i_mapping);
952 			filemap_flush(sbi->direct_inode->i_mapping);
953 		}
954 
955 	/*
956 	 *      forward syncpt
957 	 */
958 	/* if last sync is same as last syncpt,
959 	 * invoke sync point forward processing to update sync.
960 	 */
961 
962 	if (log->sync == log->syncpt) {
963 		LOGSYNC_LOCK(log, flags);
964 		if (list_empty(&log->synclist))
965 			log->sync = log->lsn;
966 		else {
967 			lp = list_entry(log->synclist.next,
968 					struct logsyncblk, synclist);
969 			log->sync = lp->lsn;
970 		}
971 		LOGSYNC_UNLOCK(log, flags);
972 
973 	}
974 
975 	/* if sync is different from last syncpt,
976 	 * write a SYNCPT record with syncpt = sync.
977 	 * reset syncpt = sync
978 	 */
979 	if (log->sync != log->syncpt) {
980 		lrd.logtid = 0;
981 		lrd.backchain = 0;
982 		lrd.type = cpu_to_le16(LOG_SYNCPT);
983 		lrd.length = 0;
984 		lrd.log.syncpt.sync = cpu_to_le32(log->sync);
985 		lsn = lmWriteRecord(log, NULL, &lrd, NULL);
986 
987 		log->syncpt = log->sync;
988 	} else
989 		lsn = log->lsn;
990 
991 	/*
992 	 *      setup next syncpt trigger (SWAG)
993 	 */
994 	logsize = log->logsize;
995 
996 	logdiff(written, lsn, log);
997 	free = logsize - written;
998 	delta = LOGSYNC_DELTA(logsize);
999 	more = min(free / 2, delta);
1000 	if (more < 2 * LOGPSIZE) {
1001 		jfs_warn("\n ... Log Wrap ... Log Wrap ... Log Wrap ...\n");
1002 		/*
1003 		 *      log wrapping
1004 		 *
1005 		 * option 1 - panic ? No.!
1006 		 * option 2 - shutdown file systems
1007 		 *            associated with log ?
1008 		 * option 3 - extend log ?
1009 		 */
1010 		/*
1011 		 * option 4 - second chance
1012 		 *
1013 		 * mark log wrapped, and continue.
1014 		 * when all active transactions are completed,
1015 		 * mark log vaild for recovery.
1016 		 * if crashed during invalid state, log state
1017 		 * implies invald log, forcing fsck().
1018 		 */
1019 		/* mark log state log wrap in log superblock */
1020 		/* log->state = LOGWRAP; */
1021 
1022 		/* reset sync point computation */
1023 		log->syncpt = log->sync = lsn;
1024 		log->nextsync = delta;
1025 	} else
1026 		/* next syncpt trigger = written + more */
1027 		log->nextsync = written + more;
1028 
1029 	/* if number of bytes written from last sync point is more
1030 	 * than 1/4 of the log size, stop new transactions from
1031 	 * starting until all current transactions are completed
1032 	 * by setting syncbarrier flag.
1033 	 */
1034 	if (!test_bit(log_SYNCBARRIER, &log->flag) &&
1035 	    (written > LOGSYNC_BARRIER(logsize)) && log->active) {
1036 		set_bit(log_SYNCBARRIER, &log->flag);
1037 		jfs_info("log barrier on: lsn=0x%x syncpt=0x%x", lsn,
1038 			 log->syncpt);
1039 		/*
1040 		 * We may have to initiate group commit
1041 		 */
1042 		jfs_flush_journal(log, 0);
1043 	}
1044 
1045 	return lsn;
1046 }
1047 
1048 /*
1049  * NAME:	jfs_syncpt
1050  *
1051  * FUNCTION:	write log SYNCPT record for specified log
1052  *
1053  * PARAMETERS:	log	  - log structure
1054  *		hard_sync - set to 1 to force metadata to be written
1055  */
1056 void jfs_syncpt(struct jfs_log *log, int hard_sync)
1057 {	LOG_LOCK(log);
1058 	lmLogSync(log, hard_sync);
1059 	LOG_UNLOCK(log);
1060 }
1061 
1062 /*
1063  * NAME:	lmLogOpen()
1064  *
1065  * FUNCTION:    open the log on first open;
1066  *	insert filesystem in the active list of the log.
1067  *
1068  * PARAMETER:	ipmnt	- file system mount inode
1069  *		iplog	- log inode (out)
1070  *
1071  * RETURN:
1072  *
1073  * serialization:
1074  */
1075 int lmLogOpen(struct super_block *sb)
1076 {
1077 	int rc;
1078 	struct block_device *bdev;
1079 	struct jfs_log *log;
1080 	struct jfs_sb_info *sbi = JFS_SBI(sb);
1081 
1082 	if (sbi->flag & JFS_NOINTEGRITY)
1083 		return open_dummy_log(sb);
1084 
1085 	if (sbi->mntflag & JFS_INLINELOG)
1086 		return open_inline_log(sb);
1087 
1088 	mutex_lock(&jfs_log_mutex);
1089 	list_for_each_entry(log, &jfs_external_logs, journal_list) {
1090 		if (log->bdev->bd_dev == sbi->logdev) {
1091 			if (memcmp(log->uuid, sbi->loguuid,
1092 				   sizeof(log->uuid))) {
1093 				jfs_warn("wrong uuid on JFS journal\n");
1094 				mutex_unlock(&jfs_log_mutex);
1095 				return -EINVAL;
1096 			}
1097 			/*
1098 			 * add file system to log active file system list
1099 			 */
1100 			if ((rc = lmLogFileSystem(log, sbi, 1))) {
1101 				mutex_unlock(&jfs_log_mutex);
1102 				return rc;
1103 			}
1104 			goto journal_found;
1105 		}
1106 	}
1107 
1108 	if (!(log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL))) {
1109 		mutex_unlock(&jfs_log_mutex);
1110 		return -ENOMEM;
1111 	}
1112 	INIT_LIST_HEAD(&log->sb_list);
1113 	init_waitqueue_head(&log->syncwait);
1114 
1115 	/*
1116 	 *      external log as separate logical volume
1117 	 *
1118 	 * file systems to log may have n-to-1 relationship;
1119 	 */
1120 
1121 	bdev = open_by_devnum(sbi->logdev, FMODE_READ|FMODE_WRITE);
1122 	if (IS_ERR(bdev)) {
1123 		rc = -PTR_ERR(bdev);
1124 		goto free;
1125 	}
1126 
1127 	if ((rc = bd_claim(bdev, log))) {
1128 		goto close;
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 unclaim;
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       unclaim:
1165 	bd_release(bdev);
1166 
1167       close:		/* close external log device */
1168 	blkdev_put(bdev);
1169 
1170       free:		/* free log descriptor */
1171 	mutex_unlock(&jfs_log_mutex);
1172 	kfree(log);
1173 
1174 	jfs_warn("lmLogOpen: exit(%d)", rc);
1175 	return rc;
1176 }
1177 
1178 static int open_inline_log(struct super_block *sb)
1179 {
1180 	struct jfs_log *log;
1181 	int rc;
1182 
1183 	if (!(log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL)))
1184 		return -ENOMEM;
1185 	INIT_LIST_HEAD(&log->sb_list);
1186 	init_waitqueue_head(&log->syncwait);
1187 
1188 	set_bit(log_INLINELOG, &log->flag);
1189 	log->bdev = sb->s_bdev;
1190 	log->base = addressPXD(&JFS_SBI(sb)->logpxd);
1191 	log->size = lengthPXD(&JFS_SBI(sb)->logpxd) >>
1192 	    (L2LOGPSIZE - sb->s_blocksize_bits);
1193 	log->l2bsize = sb->s_blocksize_bits;
1194 	ASSERT(L2LOGPSIZE >= sb->s_blocksize_bits);
1195 
1196 	/*
1197 	 * initialize log.
1198 	 */
1199 	if ((rc = lmLogInit(log))) {
1200 		kfree(log);
1201 		jfs_warn("lmLogOpen: exit(%d)", rc);
1202 		return rc;
1203 	}
1204 
1205 	list_add(&JFS_SBI(sb)->log_list, &log->sb_list);
1206 	JFS_SBI(sb)->log = log;
1207 
1208 	return rc;
1209 }
1210 
1211 static int open_dummy_log(struct super_block *sb)
1212 {
1213 	int rc;
1214 
1215 	mutex_lock(&jfs_log_mutex);
1216 	if (!dummy_log) {
1217 		dummy_log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL);
1218 		if (!dummy_log) {
1219 			mutex_unlock(&jfs_log_mutex);
1220 			return -ENOMEM;
1221 		}
1222 		INIT_LIST_HEAD(&dummy_log->sb_list);
1223 		init_waitqueue_head(&dummy_log->syncwait);
1224 		dummy_log->no_integrity = 1;
1225 		/* Make up some stuff */
1226 		dummy_log->base = 0;
1227 		dummy_log->size = 1024;
1228 		rc = lmLogInit(dummy_log);
1229 		if (rc) {
1230 			kfree(dummy_log);
1231 			dummy_log = NULL;
1232 			mutex_unlock(&jfs_log_mutex);
1233 			return rc;
1234 		}
1235 	}
1236 
1237 	LOG_LOCK(dummy_log);
1238 	list_add(&JFS_SBI(sb)->log_list, &dummy_log->sb_list);
1239 	JFS_SBI(sb)->log = dummy_log;
1240 	LOG_UNLOCK(dummy_log);
1241 	mutex_unlock(&jfs_log_mutex);
1242 
1243 	return 0;
1244 }
1245 
1246 /*
1247  * NAME:	lmLogInit()
1248  *
1249  * FUNCTION:	log initialization at first log open.
1250  *
1251  *	logredo() (or logformat()) should have been run previously.
1252  *	initialize the log from log superblock.
1253  *	set the log state in the superblock to LOGMOUNT and
1254  *	write SYNCPT log record.
1255  *
1256  * PARAMETER:	log	- log structure
1257  *
1258  * RETURN:	0	- if ok
1259  *		-EINVAL	- bad log magic number or superblock dirty
1260  *		error returned from logwait()
1261  *
1262  * serialization: single first open thread
1263  */
1264 int lmLogInit(struct jfs_log * log)
1265 {
1266 	int rc = 0;
1267 	struct lrd lrd;
1268 	struct logsuper *logsuper;
1269 	struct lbuf *bpsuper;
1270 	struct lbuf *bp;
1271 	struct logpage *lp;
1272 	int lsn = 0;
1273 
1274 	jfs_info("lmLogInit: log:0x%p", log);
1275 
1276 	/* initialize the group commit serialization lock */
1277 	LOGGC_LOCK_INIT(log);
1278 
1279 	/* allocate/initialize the log write serialization lock */
1280 	LOG_LOCK_INIT(log);
1281 
1282 	LOGSYNC_LOCK_INIT(log);
1283 
1284 	INIT_LIST_HEAD(&log->synclist);
1285 
1286 	INIT_LIST_HEAD(&log->cqueue);
1287 	log->flush_tblk = NULL;
1288 
1289 	log->count = 0;
1290 
1291 	/*
1292 	 * initialize log i/o
1293 	 */
1294 	if ((rc = lbmLogInit(log)))
1295 		return rc;
1296 
1297 	if (!test_bit(log_INLINELOG, &log->flag))
1298 		log->l2bsize = L2LOGPSIZE;
1299 
1300 	/* check for disabled journaling to disk */
1301 	if (log->no_integrity) {
1302 		/*
1303 		 * Journal pages will still be filled.  When the time comes
1304 		 * to actually do the I/O, the write is not done, and the
1305 		 * endio routine is called directly.
1306 		 */
1307 		bp = lbmAllocate(log , 0);
1308 		log->bp = bp;
1309 		bp->l_pn = bp->l_eor = 0;
1310 	} else {
1311 		/*
1312 		 * validate log superblock
1313 		 */
1314 		if ((rc = lbmRead(log, 1, &bpsuper)))
1315 			goto errout10;
1316 
1317 		logsuper = (struct logsuper *) bpsuper->l_ldata;
1318 
1319 		if (logsuper->magic != cpu_to_le32(LOGMAGIC)) {
1320 			jfs_warn("*** Log Format Error ! ***");
1321 			rc = -EINVAL;
1322 			goto errout20;
1323 		}
1324 
1325 		/* logredo() should have been run successfully. */
1326 		if (logsuper->state != cpu_to_le32(LOGREDONE)) {
1327 			jfs_warn("*** Log Is Dirty ! ***");
1328 			rc = -EINVAL;
1329 			goto errout20;
1330 		}
1331 
1332 		/* initialize log from log superblock */
1333 		if (test_bit(log_INLINELOG,&log->flag)) {
1334 			if (log->size != le32_to_cpu(logsuper->size)) {
1335 				rc = -EINVAL;
1336 				goto errout20;
1337 			}
1338 			jfs_info("lmLogInit: inline log:0x%p base:0x%Lx "
1339 				 "size:0x%x", log,
1340 				 (unsigned long long) log->base, log->size);
1341 		} else {
1342 			if (memcmp(logsuper->uuid, log->uuid, 16)) {
1343 				jfs_warn("wrong uuid on JFS log device");
1344 				goto errout20;
1345 			}
1346 			log->size = le32_to_cpu(logsuper->size);
1347 			log->l2bsize = le32_to_cpu(logsuper->l2bsize);
1348 			jfs_info("lmLogInit: external log:0x%p base:0x%Lx "
1349 				 "size:0x%x", log,
1350 				 (unsigned long long) log->base, log->size);
1351 		}
1352 
1353 		log->page = le32_to_cpu(logsuper->end) / LOGPSIZE;
1354 		log->eor = le32_to_cpu(logsuper->end) - (LOGPSIZE * log->page);
1355 
1356 		/*
1357 		 * initialize for log append write mode
1358 		 */
1359 		/* establish current/end-of-log page/buffer */
1360 		if ((rc = lbmRead(log, log->page, &bp)))
1361 			goto errout20;
1362 
1363 		lp = (struct logpage *) bp->l_ldata;
1364 
1365 		jfs_info("lmLogInit: lsn:0x%x page:%d eor:%d:%d",
1366 			 le32_to_cpu(logsuper->end), log->page, log->eor,
1367 			 le16_to_cpu(lp->h.eor));
1368 
1369 		log->bp = bp;
1370 		bp->l_pn = log->page;
1371 		bp->l_eor = log->eor;
1372 
1373 		/* if current page is full, move on to next page */
1374 		if (log->eor >= LOGPSIZE - LOGPTLRSIZE)
1375 			lmNextPage(log);
1376 
1377 		/*
1378 		 * initialize log syncpoint
1379 		 */
1380 		/*
1381 		 * write the first SYNCPT record with syncpoint = 0
1382 		 * (i.e., log redo up to HERE !);
1383 		 * remove current page from lbm write queue at end of pageout
1384 		 * (to write log superblock update), but do not release to
1385 		 * freelist;
1386 		 */
1387 		lrd.logtid = 0;
1388 		lrd.backchain = 0;
1389 		lrd.type = cpu_to_le16(LOG_SYNCPT);
1390 		lrd.length = 0;
1391 		lrd.log.syncpt.sync = 0;
1392 		lsn = lmWriteRecord(log, NULL, &lrd, NULL);
1393 		bp = log->bp;
1394 		bp->l_ceor = bp->l_eor;
1395 		lp = (struct logpage *) bp->l_ldata;
1396 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
1397 		lbmWrite(log, bp, lbmWRITE | lbmSYNC, 0);
1398 		if ((rc = lbmIOWait(bp, 0)))
1399 			goto errout30;
1400 
1401 		/*
1402 		 * update/write superblock
1403 		 */
1404 		logsuper->state = cpu_to_le32(LOGMOUNT);
1405 		log->serial = le32_to_cpu(logsuper->serial) + 1;
1406 		logsuper->serial = cpu_to_le32(log->serial);
1407 		lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1408 		if ((rc = lbmIOWait(bpsuper, lbmFREE)))
1409 			goto errout30;
1410 	}
1411 
1412 	/* initialize logsync parameters */
1413 	log->logsize = (log->size - 2) << L2LOGPSIZE;
1414 	log->lsn = lsn;
1415 	log->syncpt = lsn;
1416 	log->sync = log->syncpt;
1417 	log->nextsync = LOGSYNC_DELTA(log->logsize);
1418 
1419 	jfs_info("lmLogInit: lsn:0x%x syncpt:0x%x sync:0x%x",
1420 		 log->lsn, log->syncpt, log->sync);
1421 
1422 	/*
1423 	 * initialize for lazy/group commit
1424 	 */
1425 	log->clsn = lsn;
1426 
1427 	return 0;
1428 
1429 	/*
1430 	 *      unwind on error
1431 	 */
1432       errout30:		/* release log page */
1433 	log->wqueue = NULL;
1434 	bp->l_wqnext = NULL;
1435 	lbmFree(bp);
1436 
1437       errout20:		/* release log superblock */
1438 	lbmFree(bpsuper);
1439 
1440       errout10:		/* unwind lbmLogInit() */
1441 	lbmLogShutdown(log);
1442 
1443 	jfs_warn("lmLogInit: exit(%d)", rc);
1444 	return rc;
1445 }
1446 
1447 
1448 /*
1449  * NAME:	lmLogClose()
1450  *
1451  * FUNCTION:	remove file system <ipmnt> from active list of log <iplog>
1452  *		and close it on last close.
1453  *
1454  * PARAMETER:	sb	- superblock
1455  *
1456  * RETURN:	errors from subroutines
1457  *
1458  * serialization:
1459  */
1460 int lmLogClose(struct super_block *sb)
1461 {
1462 	struct jfs_sb_info *sbi = JFS_SBI(sb);
1463 	struct jfs_log *log = sbi->log;
1464 	struct block_device *bdev;
1465 	int rc = 0;
1466 
1467 	jfs_info("lmLogClose: log:0x%p", log);
1468 
1469 	mutex_lock(&jfs_log_mutex);
1470 	LOG_LOCK(log);
1471 	list_del(&sbi->log_list);
1472 	LOG_UNLOCK(log);
1473 	sbi->log = NULL;
1474 
1475 	/*
1476 	 * We need to make sure all of the "written" metapages
1477 	 * actually make it to disk
1478 	 */
1479 	sync_blockdev(sb->s_bdev);
1480 
1481 	if (test_bit(log_INLINELOG, &log->flag)) {
1482 		/*
1483 		 *      in-line log in host file system
1484 		 */
1485 		rc = lmLogShutdown(log);
1486 		kfree(log);
1487 		goto out;
1488 	}
1489 
1490 	if (!log->no_integrity)
1491 		lmLogFileSystem(log, sbi, 0);
1492 
1493 	if (!list_empty(&log->sb_list))
1494 		goto out;
1495 
1496 	/*
1497 	 * TODO: ensure that the dummy_log is in a state to allow
1498 	 * lbmLogShutdown to deallocate all the buffers and call
1499 	 * kfree against dummy_log.  For now, leave dummy_log & its
1500 	 * buffers in memory, and resuse if another no-integrity mount
1501 	 * is requested.
1502 	 */
1503 	if (log->no_integrity)
1504 		goto out;
1505 
1506 	/*
1507 	 *      external log as separate logical volume
1508 	 */
1509 	list_del(&log->journal_list);
1510 	bdev = log->bdev;
1511 	rc = lmLogShutdown(log);
1512 
1513 	bd_release(bdev);
1514 	blkdev_put(bdev);
1515 
1516 	kfree(log);
1517 
1518       out:
1519 	mutex_unlock(&jfs_log_mutex);
1520 	jfs_info("lmLogClose: exit(%d)", rc);
1521 	return rc;
1522 }
1523 
1524 
1525 /*
1526  * NAME:	jfs_flush_journal()
1527  *
1528  * FUNCTION:	initiate write of any outstanding transactions to the journal
1529  *		and optionally wait until they are all written to disk
1530  *
1531  *		wait == 0  flush until latest txn is committed, don't wait
1532  *		wait == 1  flush until latest txn is committed, wait
1533  *		wait > 1   flush until all txn's are complete, wait
1534  */
1535 void jfs_flush_journal(struct jfs_log *log, int wait)
1536 {
1537 	int i;
1538 	struct tblock *target = NULL;
1539 	struct jfs_sb_info *sbi;
1540 
1541 	/* jfs_write_inode may call us during read-only mount */
1542 	if (!log)
1543 		return;
1544 
1545 	jfs_info("jfs_flush_journal: log:0x%p wait=%d", log, wait);
1546 
1547 	LOGGC_LOCK(log);
1548 
1549 	if (!list_empty(&log->cqueue)) {
1550 		/*
1551 		 * This ensures that we will keep writing to the journal as long
1552 		 * as there are unwritten commit records
1553 		 */
1554 		target = list_entry(log->cqueue.prev, struct tblock, cqueue);
1555 
1556 		if (test_bit(log_FLUSH, &log->flag)) {
1557 			/*
1558 			 * We're already flushing.
1559 			 * if flush_tblk is NULL, we are flushing everything,
1560 			 * so leave it that way.  Otherwise, update it to the
1561 			 * latest transaction
1562 			 */
1563 			if (log->flush_tblk)
1564 				log->flush_tblk = target;
1565 		} else {
1566 			/* Only flush until latest transaction is committed */
1567 			log->flush_tblk = target;
1568 			set_bit(log_FLUSH, &log->flag);
1569 
1570 			/*
1571 			 * Initiate I/O on outstanding transactions
1572 			 */
1573 			if (!(log->cflag & logGC_PAGEOUT)) {
1574 				log->cflag |= logGC_PAGEOUT;
1575 				lmGCwrite(log, 0);
1576 			}
1577 		}
1578 	}
1579 	if ((wait > 1) || test_bit(log_SYNCBARRIER, &log->flag)) {
1580 		/* Flush until all activity complete */
1581 		set_bit(log_FLUSH, &log->flag);
1582 		log->flush_tblk = NULL;
1583 	}
1584 
1585 	if (wait && target && !(target->flag & tblkGC_COMMITTED)) {
1586 		DECLARE_WAITQUEUE(__wait, current);
1587 
1588 		add_wait_queue(&target->gcwait, &__wait);
1589 		set_current_state(TASK_UNINTERRUPTIBLE);
1590 		LOGGC_UNLOCK(log);
1591 		schedule();
1592 		__set_current_state(TASK_RUNNING);
1593 		LOGGC_LOCK(log);
1594 		remove_wait_queue(&target->gcwait, &__wait);
1595 	}
1596 	LOGGC_UNLOCK(log);
1597 
1598 	if (wait < 2)
1599 		return;
1600 
1601 	list_for_each_entry(sbi, &log->sb_list, log_list) {
1602 		filemap_fdatawrite(sbi->ipbmap->i_mapping);
1603 		filemap_fdatawrite(sbi->ipimap->i_mapping);
1604 		filemap_fdatawrite(sbi->direct_inode->i_mapping);
1605 	}
1606 
1607 	/*
1608 	 * If there was recent activity, we may need to wait
1609 	 * for the lazycommit thread to catch up
1610 	 */
1611 	if ((!list_empty(&log->cqueue)) || !list_empty(&log->synclist)) {
1612 		for (i = 0; i < 200; i++) {	/* Too much? */
1613 			msleep(250);
1614 			if (list_empty(&log->cqueue) &&
1615 			    list_empty(&log->synclist))
1616 				break;
1617 		}
1618 	}
1619 	assert(list_empty(&log->cqueue));
1620 
1621 #ifdef CONFIG_JFS_DEBUG
1622 	if (!list_empty(&log->synclist)) {
1623 		struct logsyncblk *lp;
1624 
1625 		list_for_each_entry(lp, &log->synclist, synclist) {
1626 			if (lp->xflag & COMMIT_PAGE) {
1627 				struct metapage *mp = (struct metapage *)lp;
1628 				dump_mem("orphan metapage", lp,
1629 					 sizeof(struct metapage));
1630 				dump_mem("page", mp->page, sizeof(struct page));
1631 			}
1632 			else
1633 				dump_mem("orphan tblock", lp,
1634 					 sizeof(struct tblock));
1635 		}
1636 	}
1637 #endif
1638 	//assert(list_empty(&log->synclist));
1639 	clear_bit(log_FLUSH, &log->flag);
1640 }
1641 
1642 /*
1643  * NAME:	lmLogShutdown()
1644  *
1645  * FUNCTION:	log shutdown at last LogClose().
1646  *
1647  *		write log syncpt record.
1648  *		update super block to set redone flag to 0.
1649  *
1650  * PARAMETER:	log	- log inode
1651  *
1652  * RETURN:	0	- success
1653  *
1654  * serialization: single last close thread
1655  */
1656 int lmLogShutdown(struct jfs_log * log)
1657 {
1658 	int rc;
1659 	struct lrd lrd;
1660 	int lsn;
1661 	struct logsuper *logsuper;
1662 	struct lbuf *bpsuper;
1663 	struct lbuf *bp;
1664 	struct logpage *lp;
1665 
1666 	jfs_info("lmLogShutdown: log:0x%p", log);
1667 
1668 	jfs_flush_journal(log, 2);
1669 
1670 	/*
1671 	 * write the last SYNCPT record with syncpoint = 0
1672 	 * (i.e., log redo up to HERE !)
1673 	 */
1674 	lrd.logtid = 0;
1675 	lrd.backchain = 0;
1676 	lrd.type = cpu_to_le16(LOG_SYNCPT);
1677 	lrd.length = 0;
1678 	lrd.log.syncpt.sync = 0;
1679 
1680 	lsn = lmWriteRecord(log, NULL, &lrd, NULL);
1681 	bp = log->bp;
1682 	lp = (struct logpage *) bp->l_ldata;
1683 	lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
1684 	lbmWrite(log, log->bp, lbmWRITE | lbmRELEASE | lbmSYNC, 0);
1685 	lbmIOWait(log->bp, lbmFREE);
1686 	log->bp = NULL;
1687 
1688 	/*
1689 	 * synchronous update log superblock
1690 	 * mark log state as shutdown cleanly
1691 	 * (i.e., Log does not need to be replayed).
1692 	 */
1693 	if ((rc = lbmRead(log, 1, &bpsuper)))
1694 		goto out;
1695 
1696 	logsuper = (struct logsuper *) bpsuper->l_ldata;
1697 	logsuper->state = cpu_to_le32(LOGREDONE);
1698 	logsuper->end = cpu_to_le32(lsn);
1699 	lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1700 	rc = lbmIOWait(bpsuper, lbmFREE);
1701 
1702 	jfs_info("lmLogShutdown: lsn:0x%x page:%d eor:%d",
1703 		 lsn, log->page, log->eor);
1704 
1705       out:
1706 	/*
1707 	 * shutdown per log i/o
1708 	 */
1709 	lbmLogShutdown(log);
1710 
1711 	if (rc) {
1712 		jfs_warn("lmLogShutdown: exit(%d)", rc);
1713 	}
1714 	return rc;
1715 }
1716 
1717 
1718 /*
1719  * NAME:	lmLogFileSystem()
1720  *
1721  * FUNCTION:	insert (<activate> = true)/remove (<activate> = false)
1722  *	file system into/from log active file system list.
1723  *
1724  * PARAMETE:	log	- pointer to logs inode.
1725  *		fsdev	- kdev_t of filesystem.
1726  *		serial  - pointer to returned log serial number
1727  *		activate - insert/remove device from active list.
1728  *
1729  * RETURN:	0	- success
1730  *		errors returned by vms_iowait().
1731  */
1732 static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
1733 			   int activate)
1734 {
1735 	int rc = 0;
1736 	int i;
1737 	struct logsuper *logsuper;
1738 	struct lbuf *bpsuper;
1739 	char *uuid = sbi->uuid;
1740 
1741 	/*
1742 	 * insert/remove file system device to log active file system list.
1743 	 */
1744 	if ((rc = lbmRead(log, 1, &bpsuper)))
1745 		return rc;
1746 
1747 	logsuper = (struct logsuper *) bpsuper->l_ldata;
1748 	if (activate) {
1749 		for (i = 0; i < MAX_ACTIVE; i++)
1750 			if (!memcmp(logsuper->active[i].uuid, NULL_UUID, 16)) {
1751 				memcpy(logsuper->active[i].uuid, uuid, 16);
1752 				sbi->aggregate = i;
1753 				break;
1754 			}
1755 		if (i == MAX_ACTIVE) {
1756 			jfs_warn("Too many file systems sharing journal!");
1757 			lbmFree(bpsuper);
1758 			return -EMFILE;	/* Is there a better rc? */
1759 		}
1760 	} else {
1761 		for (i = 0; i < MAX_ACTIVE; i++)
1762 			if (!memcmp(logsuper->active[i].uuid, uuid, 16)) {
1763 				memcpy(logsuper->active[i].uuid, NULL_UUID, 16);
1764 				break;
1765 			}
1766 		if (i == MAX_ACTIVE) {
1767 			jfs_warn("Somebody stomped on the journal!");
1768 			lbmFree(bpsuper);
1769 			return -EIO;
1770 		}
1771 
1772 	}
1773 
1774 	/*
1775 	 * synchronous write log superblock:
1776 	 *
1777 	 * write sidestream bypassing write queue:
1778 	 * at file system mount, log super block is updated for
1779 	 * activation of the file system before any log record
1780 	 * (MOUNT record) of the file system, and at file system
1781 	 * unmount, all meta data for the file system has been
1782 	 * flushed before log super block is updated for deactivation
1783 	 * of the file system.
1784 	 */
1785 	lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1786 	rc = lbmIOWait(bpsuper, lbmFREE);
1787 
1788 	return rc;
1789 }
1790 
1791 /*
1792  *		log buffer manager (lbm)
1793  *		------------------------
1794  *
1795  * special purpose buffer manager supporting log i/o requirements.
1796  *
1797  * per log write queue:
1798  * log pageout occurs in serial order by fifo write queue and
1799  * restricting to a single i/o in pregress at any one time.
1800  * a circular singly-linked list
1801  * (log->wrqueue points to the tail, and buffers are linked via
1802  * bp->wrqueue field), and
1803  * maintains log page in pageout ot waiting for pageout in serial pageout.
1804  */
1805 
1806 /*
1807  *	lbmLogInit()
1808  *
1809  * initialize per log I/O setup at lmLogInit()
1810  */
1811 static int lbmLogInit(struct jfs_log * log)
1812 {				/* log inode */
1813 	int i;
1814 	struct lbuf *lbuf;
1815 
1816 	jfs_info("lbmLogInit: log:0x%p", log);
1817 
1818 	/* initialize current buffer cursor */
1819 	log->bp = NULL;
1820 
1821 	/* initialize log device write queue */
1822 	log->wqueue = NULL;
1823 
1824 	/*
1825 	 * Each log has its own buffer pages allocated to it.  These are
1826 	 * not managed by the page cache.  This ensures that a transaction
1827 	 * writing to the log does not block trying to allocate a page from
1828 	 * the page cache (for the log).  This would be bad, since page
1829 	 * allocation waits on the kswapd thread that may be committing inodes
1830 	 * which would cause log activity.  Was that clear?  I'm trying to
1831 	 * avoid deadlock here.
1832 	 */
1833 	init_waitqueue_head(&log->free_wait);
1834 
1835 	log->lbuf_free = NULL;
1836 
1837 	for (i = 0; i < LOGPAGES;) {
1838 		char *buffer;
1839 		uint offset;
1840 		struct page *page;
1841 
1842 		buffer = (char *) get_zeroed_page(GFP_KERNEL);
1843 		if (buffer == NULL)
1844 			goto error;
1845 		page = virt_to_page(buffer);
1846 		for (offset = 0; offset < PAGE_SIZE; offset += LOGPSIZE) {
1847 			lbuf = kmalloc(sizeof(struct lbuf), GFP_KERNEL);
1848 			if (lbuf == NULL) {
1849 				if (offset == 0)
1850 					free_page((unsigned long) buffer);
1851 				goto error;
1852 			}
1853 			if (offset) /* we already have one reference */
1854 				get_page(page);
1855 			lbuf->l_offset = offset;
1856 			lbuf->l_ldata = buffer + offset;
1857 			lbuf->l_page = page;
1858 			lbuf->l_log = log;
1859 			init_waitqueue_head(&lbuf->l_ioevent);
1860 
1861 			lbuf->l_freelist = log->lbuf_free;
1862 			log->lbuf_free = lbuf;
1863 			i++;
1864 		}
1865 	}
1866 
1867 	return (0);
1868 
1869       error:
1870 	lbmLogShutdown(log);
1871 	return -ENOMEM;
1872 }
1873 
1874 
1875 /*
1876  *	lbmLogShutdown()
1877  *
1878  * finalize per log I/O setup at lmLogShutdown()
1879  */
1880 static void lbmLogShutdown(struct jfs_log * log)
1881 {
1882 	struct lbuf *lbuf;
1883 
1884 	jfs_info("lbmLogShutdown: log:0x%p", log);
1885 
1886 	lbuf = log->lbuf_free;
1887 	while (lbuf) {
1888 		struct lbuf *next = lbuf->l_freelist;
1889 		__free_page(lbuf->l_page);
1890 		kfree(lbuf);
1891 		lbuf = next;
1892 	}
1893 }
1894 
1895 
1896 /*
1897  *	lbmAllocate()
1898  *
1899  * allocate an empty log buffer
1900  */
1901 static struct lbuf *lbmAllocate(struct jfs_log * log, int pn)
1902 {
1903 	struct lbuf *bp;
1904 	unsigned long flags;
1905 
1906 	/*
1907 	 * recycle from log buffer freelist if any
1908 	 */
1909 	LCACHE_LOCK(flags);
1910 	LCACHE_SLEEP_COND(log->free_wait, (bp = log->lbuf_free), flags);
1911 	log->lbuf_free = bp->l_freelist;
1912 	LCACHE_UNLOCK(flags);
1913 
1914 	bp->l_flag = 0;
1915 
1916 	bp->l_wqnext = NULL;
1917 	bp->l_freelist = NULL;
1918 
1919 	bp->l_pn = pn;
1920 	bp->l_blkno = log->base + (pn << (L2LOGPSIZE - log->l2bsize));
1921 	bp->l_ceor = 0;
1922 
1923 	return bp;
1924 }
1925 
1926 
1927 /*
1928  *	lbmFree()
1929  *
1930  * release a log buffer to freelist
1931  */
1932 static void lbmFree(struct lbuf * bp)
1933 {
1934 	unsigned long flags;
1935 
1936 	LCACHE_LOCK(flags);
1937 
1938 	lbmfree(bp);
1939 
1940 	LCACHE_UNLOCK(flags);
1941 }
1942 
1943 static void lbmfree(struct lbuf * bp)
1944 {
1945 	struct jfs_log *log = bp->l_log;
1946 
1947 	assert(bp->l_wqnext == NULL);
1948 
1949 	/*
1950 	 * return the buffer to head of freelist
1951 	 */
1952 	bp->l_freelist = log->lbuf_free;
1953 	log->lbuf_free = bp;
1954 
1955 	wake_up(&log->free_wait);
1956 	return;
1957 }
1958 
1959 
1960 /*
1961  * NAME:	lbmRedrive
1962  *
1963  * FUNCTION:	add a log buffer to the log redrive list
1964  *
1965  * PARAMETER:
1966  *     bp	- log buffer
1967  *
1968  * NOTES:
1969  *	Takes log_redrive_lock.
1970  */
1971 static inline void lbmRedrive(struct lbuf *bp)
1972 {
1973 	unsigned long flags;
1974 
1975 	spin_lock_irqsave(&log_redrive_lock, flags);
1976 	bp->l_redrive_next = log_redrive_list;
1977 	log_redrive_list = bp;
1978 	spin_unlock_irqrestore(&log_redrive_lock, flags);
1979 
1980 	wake_up_process(jfsIOthread);
1981 }
1982 
1983 
1984 /*
1985  *	lbmRead()
1986  */
1987 static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
1988 {
1989 	struct bio *bio;
1990 	struct lbuf *bp;
1991 
1992 	/*
1993 	 * allocate a log buffer
1994 	 */
1995 	*bpp = bp = lbmAllocate(log, pn);
1996 	jfs_info("lbmRead: bp:0x%p pn:0x%x", bp, pn);
1997 
1998 	bp->l_flag |= lbmREAD;
1999 
2000 	bio = bio_alloc(GFP_NOFS, 1);
2001 
2002 	bio->bi_sector = bp->l_blkno << (log->l2bsize - 9);
2003 	bio->bi_bdev = log->bdev;
2004 	bio->bi_io_vec[0].bv_page = bp->l_page;
2005 	bio->bi_io_vec[0].bv_len = LOGPSIZE;
2006 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
2007 
2008 	bio->bi_vcnt = 1;
2009 	bio->bi_idx = 0;
2010 	bio->bi_size = LOGPSIZE;
2011 
2012 	bio->bi_end_io = lbmIODone;
2013 	bio->bi_private = bp;
2014 	submit_bio(READ_SYNC, bio);
2015 
2016 	wait_event(bp->l_ioevent, (bp->l_flag != lbmREAD));
2017 
2018 	return 0;
2019 }
2020 
2021 
2022 /*
2023  *	lbmWrite()
2024  *
2025  * buffer at head of pageout queue stays after completion of
2026  * partial-page pageout and redriven by explicit initiation of
2027  * pageout by caller until full-page pageout is completed and
2028  * released.
2029  *
2030  * device driver i/o done redrives pageout of new buffer at
2031  * head of pageout queue when current buffer at head of pageout
2032  * queue is released at the completion of its full-page pageout.
2033  *
2034  * LOGGC_LOCK() serializes lbmWrite() by lmNextPage() and lmGroupCommit().
2035  * LCACHE_LOCK() serializes xflag between lbmWrite() and lbmIODone()
2036  */
2037 static void lbmWrite(struct jfs_log * log, struct lbuf * bp, int flag,
2038 		     int cant_block)
2039 {
2040 	struct lbuf *tail;
2041 	unsigned long flags;
2042 
2043 	jfs_info("lbmWrite: bp:0x%p flag:0x%x pn:0x%x", bp, flag, bp->l_pn);
2044 
2045 	/* map the logical block address to physical block address */
2046 	bp->l_blkno =
2047 	    log->base + (bp->l_pn << (L2LOGPSIZE - log->l2bsize));
2048 
2049 	LCACHE_LOCK(flags);		/* disable+lock */
2050 
2051 	/*
2052 	 * initialize buffer for device driver
2053 	 */
2054 	bp->l_flag = flag;
2055 
2056 	/*
2057 	 *      insert bp at tail of write queue associated with log
2058 	 *
2059 	 * (request is either for bp already/currently at head of queue
2060 	 * or new bp to be inserted at tail)
2061 	 */
2062 	tail = log->wqueue;
2063 
2064 	/* is buffer not already on write queue ? */
2065 	if (bp->l_wqnext == NULL) {
2066 		/* insert at tail of wqueue */
2067 		if (tail == NULL) {
2068 			log->wqueue = bp;
2069 			bp->l_wqnext = bp;
2070 		} else {
2071 			log->wqueue = bp;
2072 			bp->l_wqnext = tail->l_wqnext;
2073 			tail->l_wqnext = bp;
2074 		}
2075 
2076 		tail = bp;
2077 	}
2078 
2079 	/* is buffer at head of wqueue and for write ? */
2080 	if ((bp != tail->l_wqnext) || !(flag & lbmWRITE)) {
2081 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2082 		return;
2083 	}
2084 
2085 	LCACHE_UNLOCK(flags);	/* unlock+enable */
2086 
2087 	if (cant_block)
2088 		lbmRedrive(bp);
2089 	else if (flag & lbmSYNC)
2090 		lbmStartIO(bp);
2091 	else {
2092 		LOGGC_UNLOCK(log);
2093 		lbmStartIO(bp);
2094 		LOGGC_LOCK(log);
2095 	}
2096 }
2097 
2098 
2099 /*
2100  *	lbmDirectWrite()
2101  *
2102  * initiate pageout bypassing write queue for sidestream
2103  * (e.g., log superblock) write;
2104  */
2105 static void lbmDirectWrite(struct jfs_log * log, struct lbuf * bp, int flag)
2106 {
2107 	jfs_info("lbmDirectWrite: bp:0x%p flag:0x%x pn:0x%x",
2108 		 bp, flag, bp->l_pn);
2109 
2110 	/*
2111 	 * initialize buffer for device driver
2112 	 */
2113 	bp->l_flag = flag | lbmDIRECT;
2114 
2115 	/* map the logical block address to physical block address */
2116 	bp->l_blkno =
2117 	    log->base + (bp->l_pn << (L2LOGPSIZE - log->l2bsize));
2118 
2119 	/*
2120 	 *      initiate pageout of the page
2121 	 */
2122 	lbmStartIO(bp);
2123 }
2124 
2125 
2126 /*
2127  * NAME:	lbmStartIO()
2128  *
2129  * FUNCTION:	Interface to DD strategy routine
2130  *
2131  * RETURN:      none
2132  *
2133  * serialization: LCACHE_LOCK() is NOT held during log i/o;
2134  */
2135 static void lbmStartIO(struct lbuf * bp)
2136 {
2137 	struct bio *bio;
2138 	struct jfs_log *log = bp->l_log;
2139 
2140 	jfs_info("lbmStartIO\n");
2141 
2142 	bio = bio_alloc(GFP_NOFS, 1);
2143 	bio->bi_sector = bp->l_blkno << (log->l2bsize - 9);
2144 	bio->bi_bdev = log->bdev;
2145 	bio->bi_io_vec[0].bv_page = bp->l_page;
2146 	bio->bi_io_vec[0].bv_len = LOGPSIZE;
2147 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
2148 
2149 	bio->bi_vcnt = 1;
2150 	bio->bi_idx = 0;
2151 	bio->bi_size = LOGPSIZE;
2152 
2153 	bio->bi_end_io = lbmIODone;
2154 	bio->bi_private = bp;
2155 
2156 	/* check if journaling to disk has been disabled */
2157 	if (log->no_integrity) {
2158 		bio->bi_size = 0;
2159 		lbmIODone(bio, 0, 0);
2160 	} else {
2161 		submit_bio(WRITE_SYNC, bio);
2162 		INCREMENT(lmStat.submitted);
2163 	}
2164 }
2165 
2166 
2167 /*
2168  *	lbmIOWait()
2169  */
2170 static int lbmIOWait(struct lbuf * bp, int flag)
2171 {
2172 	unsigned long flags;
2173 	int rc = 0;
2174 
2175 	jfs_info("lbmIOWait1: bp:0x%p flag:0x%x:0x%x", bp, bp->l_flag, flag);
2176 
2177 	LCACHE_LOCK(flags);		/* disable+lock */
2178 
2179 	LCACHE_SLEEP_COND(bp->l_ioevent, (bp->l_flag & lbmDONE), flags);
2180 
2181 	rc = (bp->l_flag & lbmERROR) ? -EIO : 0;
2182 
2183 	if (flag & lbmFREE)
2184 		lbmfree(bp);
2185 
2186 	LCACHE_UNLOCK(flags);	/* unlock+enable */
2187 
2188 	jfs_info("lbmIOWait2: bp:0x%p flag:0x%x:0x%x", bp, bp->l_flag, flag);
2189 	return rc;
2190 }
2191 
2192 /*
2193  *	lbmIODone()
2194  *
2195  * executed at INTIODONE level
2196  */
2197 static int lbmIODone(struct bio *bio, unsigned int bytes_done, int error)
2198 {
2199 	struct lbuf *bp = bio->bi_private;
2200 	struct lbuf *nextbp, *tail;
2201 	struct jfs_log *log;
2202 	unsigned long flags;
2203 
2204 	if (bio->bi_size)
2205 		return 1;
2206 
2207 	/*
2208 	 * get back jfs buffer bound to the i/o buffer
2209 	 */
2210 	jfs_info("lbmIODone: bp:0x%p flag:0x%x", bp, bp->l_flag);
2211 
2212 	LCACHE_LOCK(flags);		/* disable+lock */
2213 
2214 	bp->l_flag |= lbmDONE;
2215 
2216 	if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
2217 		bp->l_flag |= lbmERROR;
2218 
2219 		jfs_err("lbmIODone: I/O error in JFS log");
2220 	}
2221 
2222 	bio_put(bio);
2223 
2224 	/*
2225 	 *      pagein completion
2226 	 */
2227 	if (bp->l_flag & lbmREAD) {
2228 		bp->l_flag &= ~lbmREAD;
2229 
2230 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2231 
2232 		/* wakeup I/O initiator */
2233 		LCACHE_WAKEUP(&bp->l_ioevent);
2234 
2235 		return 0;
2236 	}
2237 
2238 	/*
2239 	 *      pageout completion
2240 	 *
2241 	 * the bp at the head of write queue has completed pageout.
2242 	 *
2243 	 * if single-commit/full-page pageout, remove the current buffer
2244 	 * from head of pageout queue, and redrive pageout with
2245 	 * the new buffer at head of pageout queue;
2246 	 * otherwise, the partial-page pageout buffer stays at
2247 	 * the head of pageout queue to be redriven for pageout
2248 	 * by lmGroupCommit() until full-page pageout is completed.
2249 	 */
2250 	bp->l_flag &= ~lbmWRITE;
2251 	INCREMENT(lmStat.pagedone);
2252 
2253 	/* update committed lsn */
2254 	log = bp->l_log;
2255 	log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor;
2256 
2257 	if (bp->l_flag & lbmDIRECT) {
2258 		LCACHE_WAKEUP(&bp->l_ioevent);
2259 		LCACHE_UNLOCK(flags);
2260 		return 0;
2261 	}
2262 
2263 	tail = log->wqueue;
2264 
2265 	/* single element queue */
2266 	if (bp == tail) {
2267 		/* remove head buffer of full-page pageout
2268 		 * from log device write queue
2269 		 */
2270 		if (bp->l_flag & lbmRELEASE) {
2271 			log->wqueue = NULL;
2272 			bp->l_wqnext = NULL;
2273 		}
2274 	}
2275 	/* multi element queue */
2276 	else {
2277 		/* remove head buffer of full-page pageout
2278 		 * from log device write queue
2279 		 */
2280 		if (bp->l_flag & lbmRELEASE) {
2281 			nextbp = tail->l_wqnext = bp->l_wqnext;
2282 			bp->l_wqnext = NULL;
2283 
2284 			/*
2285 			 * redrive pageout of next page at head of write queue:
2286 			 * redrive next page without any bound tblk
2287 			 * (i.e., page w/o any COMMIT records), or
2288 			 * first page of new group commit which has been
2289 			 * queued after current page (subsequent pageout
2290 			 * is performed synchronously, except page without
2291 			 * any COMMITs) by lmGroupCommit() as indicated
2292 			 * by lbmWRITE flag;
2293 			 */
2294 			if (nextbp->l_flag & lbmWRITE) {
2295 				/*
2296 				 * We can't do the I/O at interrupt time.
2297 				 * The jfsIO thread can do it
2298 				 */
2299 				lbmRedrive(nextbp);
2300 			}
2301 		}
2302 	}
2303 
2304 	/*
2305 	 *      synchronous pageout:
2306 	 *
2307 	 * buffer has not necessarily been removed from write queue
2308 	 * (e.g., synchronous write of partial-page with COMMIT):
2309 	 * leave buffer for i/o initiator to dispose
2310 	 */
2311 	if (bp->l_flag & lbmSYNC) {
2312 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2313 
2314 		/* wakeup I/O initiator */
2315 		LCACHE_WAKEUP(&bp->l_ioevent);
2316 	}
2317 
2318 	/*
2319 	 *      Group Commit pageout:
2320 	 */
2321 	else if (bp->l_flag & lbmGC) {
2322 		LCACHE_UNLOCK(flags);
2323 		lmPostGC(bp);
2324 	}
2325 
2326 	/*
2327 	 *      asynchronous pageout:
2328 	 *
2329 	 * buffer must have been removed from write queue:
2330 	 * insert buffer at head of freelist where it can be recycled
2331 	 */
2332 	else {
2333 		assert(bp->l_flag & lbmRELEASE);
2334 		assert(bp->l_flag & lbmFREE);
2335 		lbmfree(bp);
2336 
2337 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2338 	}
2339 
2340 	return 0;
2341 }
2342 
2343 int jfsIOWait(void *arg)
2344 {
2345 	struct lbuf *bp;
2346 
2347 	do {
2348 		spin_lock_irq(&log_redrive_lock);
2349 		while ((bp = log_redrive_list) != 0) {
2350 			log_redrive_list = bp->l_redrive_next;
2351 			bp->l_redrive_next = NULL;
2352 			spin_unlock_irq(&log_redrive_lock);
2353 			lbmStartIO(bp);
2354 			spin_lock_irq(&log_redrive_lock);
2355 		}
2356 
2357 		if (freezing(current)) {
2358 			spin_unlock_irq(&log_redrive_lock);
2359 			refrigerator();
2360 		} else {
2361 			set_current_state(TASK_INTERRUPTIBLE);
2362 			spin_unlock_irq(&log_redrive_lock);
2363 			schedule();
2364 			__set_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