xref: /openbmc/linux/fs/jfs/jfs_logmgr.c (revision 37be287c)
1 /*
2  *   Copyright (C) International Business Machines Corp., 2000-2004
3  *   Portions Copyright (C) Christoph Hellwig, 2001-2002
4  *
5  *   This program is free software;  you can redistribute it and/or modify
6  *   it under the terms of the GNU General Public License as published by
7  *   the Free Software Foundation; either version 2 of the License, or
8  *   (at your option) any later version.
9  *
10  *   This program is distributed in the hope that it will be useful,
11  *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
13  *   the GNU General Public License for more details.
14  *
15  *   You should have received a copy of the GNU General Public License
16  *   along with this program;  if not, write to the Free Software
17  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  */
19 
20 /*
21  *	jfs_logmgr.c: log manager
22  *
23  * for related information, see transaction manager (jfs_txnmgr.c), and
24  * recovery manager (jfs_logredo.c).
25  *
26  * note: for detail, RTFS.
27  *
28  *	log buffer manager:
29  * special purpose buffer manager supporting log i/o requirements.
30  * per log serial pageout of logpage
31  * queuing i/o requests and redrive i/o at iodone
32  * maintain current logpage buffer
33  * no caching since append only
34  * appropriate jfs buffer cache buffers as needed
35  *
36  *	group commit:
37  * transactions which wrote COMMIT records in the same in-memory
38  * log page during the pageout of previous/current log page(s) are
39  * committed together by the pageout of the page.
40  *
41  *	TBD lazy commit:
42  * transactions are committed asynchronously when the log page
43  * containing it COMMIT is paged out when it becomes full;
44  *
45  *	serialization:
46  * . a per log lock serialize log write.
47  * . a per log lock serialize group commit.
48  * . a per log lock serialize log open/close;
49  *
50  *	TBD log integrity:
51  * careful-write (ping-pong) of last logpage to recover from crash
52  * in overwrite.
53  * detection of split (out-of-order) write of physical sectors
54  * of last logpage via timestamp at end of each sector
55  * with its mirror data array at trailer).
56  *
57  *	alternatives:
58  * lsn - 64-bit monotonically increasing integer vs
59  * 32-bit lspn and page eor.
60  */
61 
62 #include <linux/fs.h>
63 #include <linux/blkdev.h>
64 #include <linux/interrupt.h>
65 #include <linux/completion.h>
66 #include <linux/kthread.h>
67 #include <linux/buffer_head.h>		/* for sync_blockdev() */
68 #include <linux/bio.h>
69 #include <linux/freezer.h>
70 #include <linux/export.h>
71 #include <linux/delay.h>
72 #include <linux/mutex.h>
73 #include <linux/seq_file.h>
74 #include <linux/slab.h>
75 #include "jfs_incore.h"
76 #include "jfs_filsys.h"
77 #include "jfs_metapage.h"
78 #include "jfs_superblock.h"
79 #include "jfs_txnmgr.h"
80 #include "jfs_debug.h"
81 
82 
83 /*
84  * lbuf's ready to be redriven.  Protected by log_redrive_lock (jfsIO thread)
85  */
86 static struct lbuf *log_redrive_list;
87 static DEFINE_SPINLOCK(log_redrive_lock);
88 
89 
90 /*
91  *	log read/write serialization (per log)
92  */
93 #define LOG_LOCK_INIT(log)	mutex_init(&(log)->loglock)
94 #define LOG_LOCK(log)		mutex_lock(&((log)->loglock))
95 #define LOG_UNLOCK(log)		mutex_unlock(&((log)->loglock))
96 
97 
98 /*
99  *	log group commit serialization (per log)
100  */
101 
102 #define LOGGC_LOCK_INIT(log)	spin_lock_init(&(log)->gclock)
103 #define LOGGC_LOCK(log)		spin_lock_irq(&(log)->gclock)
104 #define LOGGC_UNLOCK(log)	spin_unlock_irq(&(log)->gclock)
105 #define LOGGC_WAKEUP(tblk)	wake_up_all(&(tblk)->gcwait)
106 
107 /*
108  *	log sync serialization (per log)
109  */
110 #define	LOGSYNC_DELTA(logsize)		min((logsize)/8, 128*LOGPSIZE)
111 #define	LOGSYNC_BARRIER(logsize)	((logsize)/4)
112 /*
113 #define	LOGSYNC_DELTA(logsize)		min((logsize)/4, 256*LOGPSIZE)
114 #define	LOGSYNC_BARRIER(logsize)	((logsize)/2)
115 */
116 
117 
118 /*
119  *	log buffer cache synchronization
120  */
121 static DEFINE_SPINLOCK(jfsLCacheLock);
122 
123 #define	LCACHE_LOCK(flags)	spin_lock_irqsave(&jfsLCacheLock, flags)
124 #define	LCACHE_UNLOCK(flags)	spin_unlock_irqrestore(&jfsLCacheLock, flags)
125 
126 /*
127  * See __SLEEP_COND in jfs_locks.h
128  */
129 #define LCACHE_SLEEP_COND(wq, cond, flags)	\
130 do {						\
131 	if (cond)				\
132 		break;				\
133 	__SLEEP_COND(wq, cond, LCACHE_LOCK(flags), LCACHE_UNLOCK(flags)); \
134 } while (0)
135 
136 #define	LCACHE_WAKEUP(event)	wake_up(event)
137 
138 
139 /*
140  *	lbuf buffer cache (lCache) control
141  */
142 /* log buffer manager pageout control (cumulative, inclusive) */
143 #define	lbmREAD		0x0001
144 #define	lbmWRITE	0x0002	/* enqueue at tail of write queue;
145 				 * init pageout if at head of queue;
146 				 */
147 #define	lbmRELEASE	0x0004	/* remove from write queue
148 				 * at completion of pageout;
149 				 * do not free/recycle it yet:
150 				 * caller will free it;
151 				 */
152 #define	lbmSYNC		0x0008	/* do not return to freelist
153 				 * when removed from write queue;
154 				 */
155 #define lbmFREE		0x0010	/* return to freelist
156 				 * at completion of pageout;
157 				 * the buffer may be recycled;
158 				 */
159 #define	lbmDONE		0x0020
160 #define	lbmERROR	0x0040
161 #define lbmGC		0x0080	/* lbmIODone to perform post-GC processing
162 				 * of log page
163 				 */
164 #define lbmDIRECT	0x0100
165 
166 /*
167  * Global list of active external journals
168  */
169 static LIST_HEAD(jfs_external_logs);
170 static struct jfs_log *dummy_log = NULL;
171 static DEFINE_MUTEX(jfs_log_mutex);
172 
173 /*
174  * forward references
175  */
176 static int lmWriteRecord(struct jfs_log * log, struct tblock * tblk,
177 			 struct lrd * lrd, struct tlock * tlck);
178 
179 static int lmNextPage(struct jfs_log * log);
180 static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
181 			   int activate);
182 
183 static int open_inline_log(struct super_block *sb);
184 static int open_dummy_log(struct super_block *sb);
185 static int lbmLogInit(struct jfs_log * log);
186 static void lbmLogShutdown(struct jfs_log * log);
187 static struct lbuf *lbmAllocate(struct jfs_log * log, int);
188 static void lbmFree(struct lbuf * bp);
189 static void lbmfree(struct lbuf * bp);
190 static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp);
191 static void lbmWrite(struct jfs_log * log, struct lbuf * bp, int flag, int cant_block);
192 static void lbmDirectWrite(struct jfs_log * log, struct lbuf * bp, int flag);
193 static int lbmIOWait(struct lbuf * bp, int flag);
194 static bio_end_io_t lbmIODone;
195 static void lbmStartIO(struct lbuf * bp);
196 static void lmGCwrite(struct jfs_log * log, int cant_block);
197 static int lmLogSync(struct jfs_log * log, int hard_sync);
198 
199 
200 
201 /*
202  *	statistics
203  */
204 #ifdef CONFIG_JFS_STATISTICS
205 static struct lmStat {
206 	uint commit;		/* # of commit */
207 	uint pagedone;		/* # of page written */
208 	uint submitted;		/* # of pages submitted */
209 	uint full_page;		/* # of full pages submitted */
210 	uint partial_page;	/* # of partial pages submitted */
211 } lmStat;
212 #endif
213 
214 static void write_special_inodes(struct jfs_log *log,
215 				 int (*writer)(struct address_space *))
216 {
217 	struct jfs_sb_info *sbi;
218 
219 	list_for_each_entry(sbi, &log->sb_list, log_list) {
220 		writer(sbi->ipbmap->i_mapping);
221 		writer(sbi->ipimap->i_mapping);
222 		writer(sbi->direct_inode->i_mapping);
223 	}
224 }
225 
226 /*
227  * NAME:	lmLog()
228  *
229  * FUNCTION:	write a log record;
230  *
231  * PARAMETER:
232  *
233  * RETURN:	lsn - offset to the next log record to write (end-of-log);
234  *		-1  - error;
235  *
236  * note: todo: log error handler
237  */
238 int lmLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
239 	  struct tlock * tlck)
240 {
241 	int lsn;
242 	int diffp, difft;
243 	struct metapage *mp = NULL;
244 	unsigned long flags;
245 
246 	jfs_info("lmLog: log:0x%p tblk:0x%p, lrd:0x%p tlck:0x%p",
247 		 log, tblk, lrd, tlck);
248 
249 	LOG_LOCK(log);
250 
251 	/* log by (out-of-transaction) JFS ? */
252 	if (tblk == NULL)
253 		goto writeRecord;
254 
255 	/* log from page ? */
256 	if (tlck == NULL ||
257 	    tlck->type & tlckBTROOT || (mp = tlck->mp) == NULL)
258 		goto writeRecord;
259 
260 	/*
261 	 *	initialize/update page/transaction recovery lsn
262 	 */
263 	lsn = log->lsn;
264 
265 	LOGSYNC_LOCK(log, flags);
266 
267 	/*
268 	 * initialize page lsn if first log write of the page
269 	 */
270 	if (mp->lsn == 0) {
271 		mp->log = log;
272 		mp->lsn = lsn;
273 		log->count++;
274 
275 		/* insert page at tail of logsynclist */
276 		list_add_tail(&mp->synclist, &log->synclist);
277 	}
278 
279 	/*
280 	 *	initialize/update lsn of tblock of the page
281 	 *
282 	 * transaction inherits oldest lsn of pages associated
283 	 * with allocation/deallocation of resources (their
284 	 * log records are used to reconstruct allocation map
285 	 * at recovery time: inode for inode allocation map,
286 	 * B+-tree index of extent descriptors for block
287 	 * allocation map);
288 	 * allocation map pages inherit transaction lsn at
289 	 * commit time to allow forwarding log syncpt past log
290 	 * records associated with allocation/deallocation of
291 	 * resources only after persistent map of these map pages
292 	 * have been updated and propagated to home.
293 	 */
294 	/*
295 	 * initialize transaction lsn:
296 	 */
297 	if (tblk->lsn == 0) {
298 		/* inherit lsn of its first page logged */
299 		tblk->lsn = mp->lsn;
300 		log->count++;
301 
302 		/* insert tblock after the page on logsynclist */
303 		list_add(&tblk->synclist, &mp->synclist);
304 	}
305 	/*
306 	 * update transaction lsn:
307 	 */
308 	else {
309 		/* inherit oldest/smallest lsn of page */
310 		logdiff(diffp, mp->lsn, log);
311 		logdiff(difft, tblk->lsn, log);
312 		if (diffp < difft) {
313 			/* update tblock lsn with page lsn */
314 			tblk->lsn = mp->lsn;
315 
316 			/* move tblock after page on logsynclist */
317 			list_move(&tblk->synclist, &mp->synclist);
318 		}
319 	}
320 
321 	LOGSYNC_UNLOCK(log, flags);
322 
323 	/*
324 	 *	write the log record
325 	 */
326       writeRecord:
327 	lsn = lmWriteRecord(log, tblk, lrd, tlck);
328 
329 	/*
330 	 * forward log syncpt if log reached next syncpt trigger
331 	 */
332 	logdiff(diffp, lsn, log);
333 	if (diffp >= log->nextsync)
334 		lsn = lmLogSync(log, 0);
335 
336 	/* update end-of-log lsn */
337 	log->lsn = lsn;
338 
339 	LOG_UNLOCK(log);
340 
341 	/* return end-of-log address */
342 	return lsn;
343 }
344 
345 /*
346  * NAME:	lmWriteRecord()
347  *
348  * FUNCTION:	move the log record to current log page
349  *
350  * PARAMETER:	cd	- commit descriptor
351  *
352  * RETURN:	end-of-log address
353  *
354  * serialization: LOG_LOCK() held on entry/exit
355  */
356 static int
357 lmWriteRecord(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
358 	      struct tlock * tlck)
359 {
360 	int lsn = 0;		/* end-of-log address */
361 	struct lbuf *bp;	/* dst log page buffer */
362 	struct logpage *lp;	/* dst log page */
363 	caddr_t dst;		/* destination address in log page */
364 	int dstoffset;		/* end-of-log offset in log page */
365 	int freespace;		/* free space in log page */
366 	caddr_t p;		/* src meta-data page */
367 	caddr_t src;
368 	int srclen;
369 	int nbytes;		/* number of bytes to move */
370 	int i;
371 	int len;
372 	struct linelock *linelock;
373 	struct lv *lv;
374 	struct lvd *lvd;
375 	int l2linesize;
376 
377 	len = 0;
378 
379 	/* retrieve destination log page to write */
380 	bp = (struct lbuf *) log->bp;
381 	lp = (struct logpage *) bp->l_ldata;
382 	dstoffset = log->eor;
383 
384 	/* any log data to write ? */
385 	if (tlck == NULL)
386 		goto moveLrd;
387 
388 	/*
389 	 *	move log record data
390 	 */
391 	/* retrieve source meta-data page to log */
392 	if (tlck->flag & tlckPAGELOCK) {
393 		p = (caddr_t) (tlck->mp->data);
394 		linelock = (struct linelock *) & tlck->lock;
395 	}
396 	/* retrieve source in-memory inode to log */
397 	else if (tlck->flag & tlckINODELOCK) {
398 		if (tlck->type & tlckDTREE)
399 			p = (caddr_t) &JFS_IP(tlck->ip)->i_dtroot;
400 		else
401 			p = (caddr_t) &JFS_IP(tlck->ip)->i_xtroot;
402 		linelock = (struct linelock *) & tlck->lock;
403 	}
404 #ifdef	_JFS_WIP
405 	else if (tlck->flag & tlckINLINELOCK) {
406 
407 		inlinelock = (struct inlinelock *) & tlck;
408 		p = (caddr_t) & inlinelock->pxd;
409 		linelock = (struct linelock *) & tlck;
410 	}
411 #endif				/* _JFS_WIP */
412 	else {
413 		jfs_err("lmWriteRecord: UFO tlck:0x%p", tlck);
414 		return 0;	/* Probably should trap */
415 	}
416 	l2linesize = linelock->l2linesize;
417 
418       moveData:
419 	ASSERT(linelock->index <= linelock->maxcnt);
420 
421 	lv = linelock->lv;
422 	for (i = 0; i < linelock->index; i++, lv++) {
423 		if (lv->length == 0)
424 			continue;
425 
426 		/* is page full ? */
427 		if (dstoffset >= LOGPSIZE - LOGPTLRSIZE) {
428 			/* page become full: move on to next page */
429 			lmNextPage(log);
430 
431 			bp = log->bp;
432 			lp = (struct logpage *) bp->l_ldata;
433 			dstoffset = LOGPHDRSIZE;
434 		}
435 
436 		/*
437 		 * move log vector data
438 		 */
439 		src = (u8 *) p + (lv->offset << l2linesize);
440 		srclen = lv->length << l2linesize;
441 		len += srclen;
442 		while (srclen > 0) {
443 			freespace = (LOGPSIZE - LOGPTLRSIZE) - dstoffset;
444 			nbytes = min(freespace, srclen);
445 			dst = (caddr_t) lp + dstoffset;
446 			memcpy(dst, src, nbytes);
447 			dstoffset += nbytes;
448 
449 			/* is page not full ? */
450 			if (dstoffset < LOGPSIZE - LOGPTLRSIZE)
451 				break;
452 
453 			/* page become full: move on to next page */
454 			lmNextPage(log);
455 
456 			bp = (struct lbuf *) log->bp;
457 			lp = (struct logpage *) bp->l_ldata;
458 			dstoffset = LOGPHDRSIZE;
459 
460 			srclen -= nbytes;
461 			src += nbytes;
462 		}
463 
464 		/*
465 		 * move log vector descriptor
466 		 */
467 		len += 4;
468 		lvd = (struct lvd *) ((caddr_t) lp + dstoffset);
469 		lvd->offset = cpu_to_le16(lv->offset);
470 		lvd->length = cpu_to_le16(lv->length);
471 		dstoffset += 4;
472 		jfs_info("lmWriteRecord: lv offset:%d length:%d",
473 			 lv->offset, lv->length);
474 	}
475 
476 	if ((i = linelock->next)) {
477 		linelock = (struct linelock *) lid_to_tlock(i);
478 		goto moveData;
479 	}
480 
481 	/*
482 	 *	move log record descriptor
483 	 */
484       moveLrd:
485 	lrd->length = cpu_to_le16(len);
486 
487 	src = (caddr_t) lrd;
488 	srclen = LOGRDSIZE;
489 
490 	while (srclen > 0) {
491 		freespace = (LOGPSIZE - LOGPTLRSIZE) - dstoffset;
492 		nbytes = min(freespace, srclen);
493 		dst = (caddr_t) lp + dstoffset;
494 		memcpy(dst, src, nbytes);
495 
496 		dstoffset += nbytes;
497 		srclen -= nbytes;
498 
499 		/* are there more to move than freespace of page ? */
500 		if (srclen)
501 			goto pageFull;
502 
503 		/*
504 		 * end of log record descriptor
505 		 */
506 
507 		/* update last log record eor */
508 		log->eor = dstoffset;
509 		bp->l_eor = dstoffset;
510 		lsn = (log->page << L2LOGPSIZE) + dstoffset;
511 
512 		if (lrd->type & cpu_to_le16(LOG_COMMIT)) {
513 			tblk->clsn = lsn;
514 			jfs_info("wr: tclsn:0x%x, beor:0x%x", tblk->clsn,
515 				 bp->l_eor);
516 
517 			INCREMENT(lmStat.commit);	/* # of commit */
518 
519 			/*
520 			 * enqueue tblock for group commit:
521 			 *
522 			 * enqueue tblock of non-trivial/synchronous COMMIT
523 			 * at tail of group commit queue
524 			 * (trivial/asynchronous COMMITs are ignored by
525 			 * group commit.)
526 			 */
527 			LOGGC_LOCK(log);
528 
529 			/* init tblock gc state */
530 			tblk->flag = tblkGC_QUEUE;
531 			tblk->bp = log->bp;
532 			tblk->pn = log->page;
533 			tblk->eor = log->eor;
534 
535 			/* enqueue transaction to commit queue */
536 			list_add_tail(&tblk->cqueue, &log->cqueue);
537 
538 			LOGGC_UNLOCK(log);
539 		}
540 
541 		jfs_info("lmWriteRecord: lrd:0x%04x bp:0x%p pn:%d eor:0x%x",
542 			le16_to_cpu(lrd->type), log->bp, log->page, dstoffset);
543 
544 		/* page not full ? */
545 		if (dstoffset < LOGPSIZE - LOGPTLRSIZE)
546 			return lsn;
547 
548 	      pageFull:
549 		/* page become full: move on to next page */
550 		lmNextPage(log);
551 
552 		bp = (struct lbuf *) log->bp;
553 		lp = (struct logpage *) bp->l_ldata;
554 		dstoffset = LOGPHDRSIZE;
555 		src += nbytes;
556 	}
557 
558 	return lsn;
559 }
560 
561 
562 /*
563  * NAME:	lmNextPage()
564  *
565  * FUNCTION:	write current page and allocate next page.
566  *
567  * PARAMETER:	log
568  *
569  * RETURN:	0
570  *
571  * serialization: LOG_LOCK() held on entry/exit
572  */
573 static int lmNextPage(struct jfs_log * log)
574 {
575 	struct logpage *lp;
576 	int lspn;		/* log sequence page number */
577 	int pn;			/* current page number */
578 	struct lbuf *bp;
579 	struct lbuf *nextbp;
580 	struct tblock *tblk;
581 
582 	/* get current log page number and log sequence page number */
583 	pn = log->page;
584 	bp = log->bp;
585 	lp = (struct logpage *) bp->l_ldata;
586 	lspn = le32_to_cpu(lp->h.page);
587 
588 	LOGGC_LOCK(log);
589 
590 	/*
591 	 *	write or queue the full page at the tail of write queue
592 	 */
593 	/* get the tail tblk on commit queue */
594 	if (list_empty(&log->cqueue))
595 		tblk = NULL;
596 	else
597 		tblk = list_entry(log->cqueue.prev, struct tblock, cqueue);
598 
599 	/* every tblk who has COMMIT record on the current page,
600 	 * and has not been committed, must be on commit queue
601 	 * since tblk is queued at commit queueu at the time
602 	 * of writing its COMMIT record on the page before
603 	 * page becomes full (even though the tblk thread
604 	 * who wrote COMMIT record may have been suspended
605 	 * currently);
606 	 */
607 
608 	/* is page bound with outstanding tail tblk ? */
609 	if (tblk && tblk->pn == pn) {
610 		/* mark tblk for end-of-page */
611 		tblk->flag |= tblkGC_EOP;
612 
613 		if (log->cflag & logGC_PAGEOUT) {
614 			/* if page is not already on write queue,
615 			 * just enqueue (no lbmWRITE to prevent redrive)
616 			 * buffer to wqueue to ensure correct serial order
617 			 * of the pages since log pages will be added
618 			 * continuously
619 			 */
620 			if (bp->l_wqnext == NULL)
621 				lbmWrite(log, bp, 0, 0);
622 		} else {
623 			/*
624 			 * No current GC leader, initiate group commit
625 			 */
626 			log->cflag |= logGC_PAGEOUT;
627 			lmGCwrite(log, 0);
628 		}
629 	}
630 	/* page is not bound with outstanding tblk:
631 	 * init write or mark it to be redriven (lbmWRITE)
632 	 */
633 	else {
634 		/* finalize the page */
635 		bp->l_ceor = bp->l_eor;
636 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
637 		lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmFREE, 0);
638 	}
639 	LOGGC_UNLOCK(log);
640 
641 	/*
642 	 *	allocate/initialize next page
643 	 */
644 	/* if log wraps, the first data page of log is 2
645 	 * (0 never used, 1 is superblock).
646 	 */
647 	log->page = (pn == log->size - 1) ? 2 : pn + 1;
648 	log->eor = LOGPHDRSIZE;	/* ? valid page empty/full at logRedo() */
649 
650 	/* allocate/initialize next log page buffer */
651 	nextbp = lbmAllocate(log, log->page);
652 	nextbp->l_eor = log->eor;
653 	log->bp = nextbp;
654 
655 	/* initialize next log page */
656 	lp = (struct logpage *) nextbp->l_ldata;
657 	lp->h.page = lp->t.page = cpu_to_le32(lspn + 1);
658 	lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE);
659 
660 	return 0;
661 }
662 
663 
664 /*
665  * NAME:	lmGroupCommit()
666  *
667  * FUNCTION:	group commit
668  *	initiate pageout of the pages with COMMIT in the order of
669  *	page number - redrive pageout of the page at the head of
670  *	pageout queue until full page has been written.
671  *
672  * RETURN:
673  *
674  * NOTE:
675  *	LOGGC_LOCK serializes log group commit queue, and
676  *	transaction blocks on the commit queue.
677  *	N.B. LOG_LOCK is NOT held during lmGroupCommit().
678  */
679 int lmGroupCommit(struct jfs_log * log, struct tblock * tblk)
680 {
681 	int rc = 0;
682 
683 	LOGGC_LOCK(log);
684 
685 	/* group committed already ? */
686 	if (tblk->flag & tblkGC_COMMITTED) {
687 		if (tblk->flag & tblkGC_ERROR)
688 			rc = -EIO;
689 
690 		LOGGC_UNLOCK(log);
691 		return rc;
692 	}
693 	jfs_info("lmGroup Commit: tblk = 0x%p, gcrtc = %d", tblk, log->gcrtc);
694 
695 	if (tblk->xflag & COMMIT_LAZY)
696 		tblk->flag |= tblkGC_LAZY;
697 
698 	if ((!(log->cflag & logGC_PAGEOUT)) && (!list_empty(&log->cqueue)) &&
699 	    (!(tblk->xflag & COMMIT_LAZY) || test_bit(log_FLUSH, &log->flag)
700 	     || jfs_tlocks_low)) {
701 		/*
702 		 * No pageout in progress
703 		 *
704 		 * start group commit as its group leader.
705 		 */
706 		log->cflag |= logGC_PAGEOUT;
707 
708 		lmGCwrite(log, 0);
709 	}
710 
711 	if (tblk->xflag & COMMIT_LAZY) {
712 		/*
713 		 * Lazy transactions can leave now
714 		 */
715 		LOGGC_UNLOCK(log);
716 		return 0;
717 	}
718 
719 	/* lmGCwrite gives up LOGGC_LOCK, check again */
720 
721 	if (tblk->flag & tblkGC_COMMITTED) {
722 		if (tblk->flag & tblkGC_ERROR)
723 			rc = -EIO;
724 
725 		LOGGC_UNLOCK(log);
726 		return rc;
727 	}
728 
729 	/* upcount transaction waiting for completion
730 	 */
731 	log->gcrtc++;
732 	tblk->flag |= tblkGC_READY;
733 
734 	__SLEEP_COND(tblk->gcwait, (tblk->flag & tblkGC_COMMITTED),
735 		     LOGGC_LOCK(log), LOGGC_UNLOCK(log));
736 
737 	/* removed from commit queue */
738 	if (tblk->flag & tblkGC_ERROR)
739 		rc = -EIO;
740 
741 	LOGGC_UNLOCK(log);
742 	return rc;
743 }
744 
745 /*
746  * NAME:	lmGCwrite()
747  *
748  * FUNCTION:	group commit write
749  *	initiate write of log page, building a group of all transactions
750  *	with commit records on that page.
751  *
752  * RETURN:	None
753  *
754  * NOTE:
755  *	LOGGC_LOCK must be held by caller.
756  *	N.B. LOG_LOCK is NOT held during lmGroupCommit().
757  */
758 static void lmGCwrite(struct jfs_log * log, int cant_write)
759 {
760 	struct lbuf *bp;
761 	struct logpage *lp;
762 	int gcpn;		/* group commit page number */
763 	struct tblock *tblk;
764 	struct tblock *xtblk = NULL;
765 
766 	/*
767 	 * build the commit group of a log page
768 	 *
769 	 * scan commit queue and make a commit group of all
770 	 * transactions with COMMIT records on the same log page.
771 	 */
772 	/* get the head tblk on the commit queue */
773 	gcpn = list_entry(log->cqueue.next, struct tblock, cqueue)->pn;
774 
775 	list_for_each_entry(tblk, &log->cqueue, cqueue) {
776 		if (tblk->pn != gcpn)
777 			break;
778 
779 		xtblk = tblk;
780 
781 		/* state transition: (QUEUE, READY) -> COMMIT */
782 		tblk->flag |= tblkGC_COMMIT;
783 	}
784 	tblk = xtblk;		/* last tblk of the page */
785 
786 	/*
787 	 * pageout to commit transactions on the log page.
788 	 */
789 	bp = (struct lbuf *) tblk->bp;
790 	lp = (struct logpage *) bp->l_ldata;
791 	/* is page already full ? */
792 	if (tblk->flag & tblkGC_EOP) {
793 		/* mark page to free at end of group commit of the page */
794 		tblk->flag &= ~tblkGC_EOP;
795 		tblk->flag |= tblkGC_FREE;
796 		bp->l_ceor = bp->l_eor;
797 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
798 		lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmGC,
799 			 cant_write);
800 		INCREMENT(lmStat.full_page);
801 	}
802 	/* page is not yet full */
803 	else {
804 		bp->l_ceor = tblk->eor;	/* ? bp->l_ceor = bp->l_eor; */
805 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_ceor);
806 		lbmWrite(log, bp, lbmWRITE | lbmGC, cant_write);
807 		INCREMENT(lmStat.partial_page);
808 	}
809 }
810 
811 /*
812  * NAME:	lmPostGC()
813  *
814  * FUNCTION:	group commit post-processing
815  *	Processes transactions after their commit records have been written
816  *	to disk, redriving log I/O if necessary.
817  *
818  * RETURN:	None
819  *
820  * NOTE:
821  *	This routine is called a interrupt time by lbmIODone
822  */
823 static void lmPostGC(struct lbuf * bp)
824 {
825 	unsigned long flags;
826 	struct jfs_log *log = bp->l_log;
827 	struct logpage *lp;
828 	struct tblock *tblk, *temp;
829 
830 	//LOGGC_LOCK(log);
831 	spin_lock_irqsave(&log->gclock, flags);
832 	/*
833 	 * current pageout of group commit completed.
834 	 *
835 	 * remove/wakeup transactions from commit queue who were
836 	 * group committed with the current log page
837 	 */
838 	list_for_each_entry_safe(tblk, temp, &log->cqueue, cqueue) {
839 		if (!(tblk->flag & tblkGC_COMMIT))
840 			break;
841 		/* if transaction was marked GC_COMMIT then
842 		 * it has been shipped in the current pageout
843 		 * and made it to disk - it is committed.
844 		 */
845 
846 		if (bp->l_flag & lbmERROR)
847 			tblk->flag |= tblkGC_ERROR;
848 
849 		/* remove it from the commit queue */
850 		list_del(&tblk->cqueue);
851 		tblk->flag &= ~tblkGC_QUEUE;
852 
853 		if (tblk == log->flush_tblk) {
854 			/* we can stop flushing the log now */
855 			clear_bit(log_FLUSH, &log->flag);
856 			log->flush_tblk = NULL;
857 		}
858 
859 		jfs_info("lmPostGC: tblk = 0x%p, flag = 0x%x", tblk,
860 			 tblk->flag);
861 
862 		if (!(tblk->xflag & COMMIT_FORCE))
863 			/*
864 			 * Hand tblk over to lazy commit thread
865 			 */
866 			txLazyUnlock(tblk);
867 		else {
868 			/* state transition: COMMIT -> COMMITTED */
869 			tblk->flag |= tblkGC_COMMITTED;
870 
871 			if (tblk->flag & tblkGC_READY)
872 				log->gcrtc--;
873 
874 			LOGGC_WAKEUP(tblk);
875 		}
876 
877 		/* was page full before pageout ?
878 		 * (and this is the last tblk bound with the page)
879 		 */
880 		if (tblk->flag & tblkGC_FREE)
881 			lbmFree(bp);
882 		/* did page become full after pageout ?
883 		 * (and this is the last tblk bound with the page)
884 		 */
885 		else if (tblk->flag & tblkGC_EOP) {
886 			/* finalize the page */
887 			lp = (struct logpage *) bp->l_ldata;
888 			bp->l_ceor = bp->l_eor;
889 			lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
890 			jfs_info("lmPostGC: calling lbmWrite");
891 			lbmWrite(log, bp, lbmWRITE | lbmRELEASE | lbmFREE,
892 				 1);
893 		}
894 
895 	}
896 
897 	/* are there any transactions who have entered lnGroupCommit()
898 	 * (whose COMMITs are after that of the last log page written.
899 	 * They are waiting for new group commit (above at (SLEEP 1))
900 	 * or lazy transactions are on a full (queued) log page,
901 	 * select the latest ready transaction as new group leader and
902 	 * wake her up to lead her group.
903 	 */
904 	if ((!list_empty(&log->cqueue)) &&
905 	    ((log->gcrtc > 0) || (tblk->bp->l_wqnext != NULL) ||
906 	     test_bit(log_FLUSH, &log->flag) || jfs_tlocks_low))
907 		/*
908 		 * Call lmGCwrite with new group leader
909 		 */
910 		lmGCwrite(log, 1);
911 
912 	/* no transaction are ready yet (transactions are only just
913 	 * queued (GC_QUEUE) and not entered for group commit yet).
914 	 * the first transaction entering group commit
915 	 * will elect herself as new group leader.
916 	 */
917 	else
918 		log->cflag &= ~logGC_PAGEOUT;
919 
920 	//LOGGC_UNLOCK(log);
921 	spin_unlock_irqrestore(&log->gclock, flags);
922 	return;
923 }
924 
925 /*
926  * NAME:	lmLogSync()
927  *
928  * FUNCTION:	write log SYNCPT record for specified log
929  *	if new sync address is available
930  *	(normally the case if sync() is executed by back-ground
931  *	process).
932  *	calculate new value of i_nextsync which determines when
933  *	this code is called again.
934  *
935  * PARAMETERS:	log	- log structure
936  *		hard_sync - 1 to force all metadata to be written
937  *
938  * RETURN:	0
939  *
940  * serialization: LOG_LOCK() held on entry/exit
941  */
942 static int lmLogSync(struct jfs_log * log, int hard_sync)
943 {
944 	int logsize;
945 	int written;		/* written since last syncpt */
946 	int free;		/* free space left available */
947 	int delta;		/* additional delta to write normally */
948 	int more;		/* additional write granted */
949 	struct lrd lrd;
950 	int lsn;
951 	struct logsyncblk *lp;
952 	unsigned long flags;
953 
954 	/* push dirty metapages out to disk */
955 	if (hard_sync)
956 		write_special_inodes(log, filemap_fdatawrite);
957 	else
958 		write_special_inodes(log, filemap_flush);
959 
960 	/*
961 	 *	forward syncpt
962 	 */
963 	/* if last sync is same as last syncpt,
964 	 * invoke sync point forward processing to update sync.
965 	 */
966 
967 	if (log->sync == log->syncpt) {
968 		LOGSYNC_LOCK(log, flags);
969 		if (list_empty(&log->synclist))
970 			log->sync = log->lsn;
971 		else {
972 			lp = list_entry(log->synclist.next,
973 					struct logsyncblk, synclist);
974 			log->sync = lp->lsn;
975 		}
976 		LOGSYNC_UNLOCK(log, flags);
977 
978 	}
979 
980 	/* if sync is different from last syncpt,
981 	 * write a SYNCPT record with syncpt = sync.
982 	 * reset syncpt = sync
983 	 */
984 	if (log->sync != log->syncpt) {
985 		lrd.logtid = 0;
986 		lrd.backchain = 0;
987 		lrd.type = cpu_to_le16(LOG_SYNCPT);
988 		lrd.length = 0;
989 		lrd.log.syncpt.sync = cpu_to_le32(log->sync);
990 		lsn = lmWriteRecord(log, NULL, &lrd, NULL);
991 
992 		log->syncpt = log->sync;
993 	} else
994 		lsn = log->lsn;
995 
996 	/*
997 	 *	setup next syncpt trigger (SWAG)
998 	 */
999 	logsize = log->logsize;
1000 
1001 	logdiff(written, lsn, log);
1002 	free = logsize - written;
1003 	delta = LOGSYNC_DELTA(logsize);
1004 	more = min(free / 2, delta);
1005 	if (more < 2 * LOGPSIZE) {
1006 		jfs_warn("\n ... Log Wrap ... Log Wrap ... Log Wrap ...\n");
1007 		/*
1008 		 *	log wrapping
1009 		 *
1010 		 * option 1 - panic ? No.!
1011 		 * option 2 - shutdown file systems
1012 		 *	      associated with log ?
1013 		 * option 3 - extend log ?
1014 		 * option 4 - second chance
1015 		 *
1016 		 * mark log wrapped, and continue.
1017 		 * when all active transactions are completed,
1018 		 * mark log valid for recovery.
1019 		 * if crashed during invalid state, log state
1020 		 * implies invalid log, forcing fsck().
1021 		 */
1022 		/* mark log state log wrap in log superblock */
1023 		/* log->state = LOGWRAP; */
1024 
1025 		/* reset sync point computation */
1026 		log->syncpt = log->sync = lsn;
1027 		log->nextsync = delta;
1028 	} else
1029 		/* next syncpt trigger = written + more */
1030 		log->nextsync = written + more;
1031 
1032 	/* if number of bytes written from last sync point is more
1033 	 * than 1/4 of the log size, stop new transactions from
1034 	 * starting until all current transactions are completed
1035 	 * by setting syncbarrier flag.
1036 	 */
1037 	if (!test_bit(log_SYNCBARRIER, &log->flag) &&
1038 	    (written > LOGSYNC_BARRIER(logsize)) && log->active) {
1039 		set_bit(log_SYNCBARRIER, &log->flag);
1040 		jfs_info("log barrier on: lsn=0x%x syncpt=0x%x", lsn,
1041 			 log->syncpt);
1042 		/*
1043 		 * We may have to initiate group commit
1044 		 */
1045 		jfs_flush_journal(log, 0);
1046 	}
1047 
1048 	return lsn;
1049 }
1050 
1051 /*
1052  * NAME:	jfs_syncpt
1053  *
1054  * FUNCTION:	write log SYNCPT record for specified log
1055  *
1056  * PARAMETERS:	log	  - log structure
1057  *		hard_sync - set to 1 to force metadata to be written
1058  */
1059 void jfs_syncpt(struct jfs_log *log, int hard_sync)
1060 {	LOG_LOCK(log);
1061 	if (!test_bit(log_QUIESCE, &log->flag))
1062 		lmLogSync(log, hard_sync);
1063 	LOG_UNLOCK(log);
1064 }
1065 
1066 /*
1067  * NAME:	lmLogOpen()
1068  *
1069  * FUNCTION:	open the log on first open;
1070  *	insert filesystem in the active list of the log.
1071  *
1072  * PARAMETER:	ipmnt	- file system mount inode
1073  *		iplog	- log inode (out)
1074  *
1075  * RETURN:
1076  *
1077  * serialization:
1078  */
1079 int lmLogOpen(struct super_block *sb)
1080 {
1081 	int rc;
1082 	struct block_device *bdev;
1083 	struct jfs_log *log;
1084 	struct jfs_sb_info *sbi = JFS_SBI(sb);
1085 
1086 	if (sbi->flag & JFS_NOINTEGRITY)
1087 		return open_dummy_log(sb);
1088 
1089 	if (sbi->mntflag & JFS_INLINELOG)
1090 		return open_inline_log(sb);
1091 
1092 	mutex_lock(&jfs_log_mutex);
1093 	list_for_each_entry(log, &jfs_external_logs, journal_list) {
1094 		if (log->bdev->bd_dev == sbi->logdev) {
1095 			if (memcmp(log->uuid, sbi->loguuid,
1096 				   sizeof(log->uuid))) {
1097 				jfs_warn("wrong uuid on JFS journal\n");
1098 				mutex_unlock(&jfs_log_mutex);
1099 				return -EINVAL;
1100 			}
1101 			/*
1102 			 * add file system to log active file system list
1103 			 */
1104 			if ((rc = lmLogFileSystem(log, sbi, 1))) {
1105 				mutex_unlock(&jfs_log_mutex);
1106 				return rc;
1107 			}
1108 			goto journal_found;
1109 		}
1110 	}
1111 
1112 	if (!(log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL))) {
1113 		mutex_unlock(&jfs_log_mutex);
1114 		return -ENOMEM;
1115 	}
1116 	INIT_LIST_HEAD(&log->sb_list);
1117 	init_waitqueue_head(&log->syncwait);
1118 
1119 	/*
1120 	 *	external log as separate logical volume
1121 	 *
1122 	 * file systems to log may have n-to-1 relationship;
1123 	 */
1124 
1125 	bdev = blkdev_get_by_dev(sbi->logdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
1126 				 log);
1127 	if (IS_ERR(bdev)) {
1128 		rc = PTR_ERR(bdev);
1129 		goto free;
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 close;
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       close:		/* close external log device */
1166 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1167 
1168       free:		/* free log descriptor */
1169 	mutex_unlock(&jfs_log_mutex);
1170 	kfree(log);
1171 
1172 	jfs_warn("lmLogOpen: exit(%d)", rc);
1173 	return rc;
1174 }
1175 
1176 static int open_inline_log(struct super_block *sb)
1177 {
1178 	struct jfs_log *log;
1179 	int rc;
1180 
1181 	if (!(log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL)))
1182 		return -ENOMEM;
1183 	INIT_LIST_HEAD(&log->sb_list);
1184 	init_waitqueue_head(&log->syncwait);
1185 
1186 	set_bit(log_INLINELOG, &log->flag);
1187 	log->bdev = sb->s_bdev;
1188 	log->base = addressPXD(&JFS_SBI(sb)->logpxd);
1189 	log->size = lengthPXD(&JFS_SBI(sb)->logpxd) >>
1190 	    (L2LOGPSIZE - sb->s_blocksize_bits);
1191 	log->l2bsize = sb->s_blocksize_bits;
1192 	ASSERT(L2LOGPSIZE >= sb->s_blocksize_bits);
1193 
1194 	/*
1195 	 * initialize log.
1196 	 */
1197 	if ((rc = lmLogInit(log))) {
1198 		kfree(log);
1199 		jfs_warn("lmLogOpen: exit(%d)", rc);
1200 		return rc;
1201 	}
1202 
1203 	list_add(&JFS_SBI(sb)->log_list, &log->sb_list);
1204 	JFS_SBI(sb)->log = log;
1205 
1206 	return rc;
1207 }
1208 
1209 static int open_dummy_log(struct super_block *sb)
1210 {
1211 	int rc;
1212 
1213 	mutex_lock(&jfs_log_mutex);
1214 	if (!dummy_log) {
1215 		dummy_log = kzalloc(sizeof(struct jfs_log), GFP_KERNEL);
1216 		if (!dummy_log) {
1217 			mutex_unlock(&jfs_log_mutex);
1218 			return -ENOMEM;
1219 		}
1220 		INIT_LIST_HEAD(&dummy_log->sb_list);
1221 		init_waitqueue_head(&dummy_log->syncwait);
1222 		dummy_log->no_integrity = 1;
1223 		/* Make up some stuff */
1224 		dummy_log->base = 0;
1225 		dummy_log->size = 1024;
1226 		rc = lmLogInit(dummy_log);
1227 		if (rc) {
1228 			kfree(dummy_log);
1229 			dummy_log = NULL;
1230 			mutex_unlock(&jfs_log_mutex);
1231 			return rc;
1232 		}
1233 	}
1234 
1235 	LOG_LOCK(dummy_log);
1236 	list_add(&JFS_SBI(sb)->log_list, &dummy_log->sb_list);
1237 	JFS_SBI(sb)->log = dummy_log;
1238 	LOG_UNLOCK(dummy_log);
1239 	mutex_unlock(&jfs_log_mutex);
1240 
1241 	return 0;
1242 }
1243 
1244 /*
1245  * NAME:	lmLogInit()
1246  *
1247  * FUNCTION:	log initialization at first log open.
1248  *
1249  *	logredo() (or logformat()) should have been run previously.
1250  *	initialize the log from log superblock.
1251  *	set the log state in the superblock to LOGMOUNT and
1252  *	write SYNCPT log record.
1253  *
1254  * PARAMETER:	log	- log structure
1255  *
1256  * RETURN:	0	- if ok
1257  *		-EINVAL	- bad log magic number or superblock dirty
1258  *		error returned from logwait()
1259  *
1260  * serialization: single first open thread
1261  */
1262 int lmLogInit(struct jfs_log * log)
1263 {
1264 	int rc = 0;
1265 	struct lrd lrd;
1266 	struct logsuper *logsuper;
1267 	struct lbuf *bpsuper;
1268 	struct lbuf *bp;
1269 	struct logpage *lp;
1270 	int lsn = 0;
1271 
1272 	jfs_info("lmLogInit: log:0x%p", log);
1273 
1274 	/* initialize the group commit serialization lock */
1275 	LOGGC_LOCK_INIT(log);
1276 
1277 	/* allocate/initialize the log write serialization lock */
1278 	LOG_LOCK_INIT(log);
1279 
1280 	LOGSYNC_LOCK_INIT(log);
1281 
1282 	INIT_LIST_HEAD(&log->synclist);
1283 
1284 	INIT_LIST_HEAD(&log->cqueue);
1285 	log->flush_tblk = NULL;
1286 
1287 	log->count = 0;
1288 
1289 	/*
1290 	 * initialize log i/o
1291 	 */
1292 	if ((rc = lbmLogInit(log)))
1293 		return rc;
1294 
1295 	if (!test_bit(log_INLINELOG, &log->flag))
1296 		log->l2bsize = L2LOGPSIZE;
1297 
1298 	/* check for disabled journaling to disk */
1299 	if (log->no_integrity) {
1300 		/*
1301 		 * Journal pages will still be filled.  When the time comes
1302 		 * to actually do the I/O, the write is not done, and the
1303 		 * endio routine is called directly.
1304 		 */
1305 		bp = lbmAllocate(log , 0);
1306 		log->bp = bp;
1307 		bp->l_pn = bp->l_eor = 0;
1308 	} else {
1309 		/*
1310 		 * validate log superblock
1311 		 */
1312 		if ((rc = lbmRead(log, 1, &bpsuper)))
1313 			goto errout10;
1314 
1315 		logsuper = (struct logsuper *) bpsuper->l_ldata;
1316 
1317 		if (logsuper->magic != cpu_to_le32(LOGMAGIC)) {
1318 			jfs_warn("*** Log Format Error ! ***");
1319 			rc = -EINVAL;
1320 			goto errout20;
1321 		}
1322 
1323 		/* logredo() should have been run successfully. */
1324 		if (logsuper->state != cpu_to_le32(LOGREDONE)) {
1325 			jfs_warn("*** Log Is Dirty ! ***");
1326 			rc = -EINVAL;
1327 			goto errout20;
1328 		}
1329 
1330 		/* initialize log from log superblock */
1331 		if (test_bit(log_INLINELOG,&log->flag)) {
1332 			if (log->size != le32_to_cpu(logsuper->size)) {
1333 				rc = -EINVAL;
1334 				goto errout20;
1335 			}
1336 			jfs_info("lmLogInit: inline log:0x%p base:0x%Lx "
1337 				 "size:0x%x", log,
1338 				 (unsigned long long) log->base, log->size);
1339 		} else {
1340 			if (memcmp(logsuper->uuid, log->uuid, 16)) {
1341 				jfs_warn("wrong uuid on JFS log device");
1342 				goto errout20;
1343 			}
1344 			log->size = le32_to_cpu(logsuper->size);
1345 			log->l2bsize = le32_to_cpu(logsuper->l2bsize);
1346 			jfs_info("lmLogInit: external log:0x%p base:0x%Lx "
1347 				 "size:0x%x", log,
1348 				 (unsigned long long) log->base, log->size);
1349 		}
1350 
1351 		log->page = le32_to_cpu(logsuper->end) / LOGPSIZE;
1352 		log->eor = le32_to_cpu(logsuper->end) - (LOGPSIZE * log->page);
1353 
1354 		/*
1355 		 * initialize for log append write mode
1356 		 */
1357 		/* establish current/end-of-log page/buffer */
1358 		if ((rc = lbmRead(log, log->page, &bp)))
1359 			goto errout20;
1360 
1361 		lp = (struct logpage *) bp->l_ldata;
1362 
1363 		jfs_info("lmLogInit: lsn:0x%x page:%d eor:%d:%d",
1364 			 le32_to_cpu(logsuper->end), log->page, log->eor,
1365 			 le16_to_cpu(lp->h.eor));
1366 
1367 		log->bp = bp;
1368 		bp->l_pn = log->page;
1369 		bp->l_eor = log->eor;
1370 
1371 		/* if current page is full, move on to next page */
1372 		if (log->eor >= LOGPSIZE - LOGPTLRSIZE)
1373 			lmNextPage(log);
1374 
1375 		/*
1376 		 * initialize log syncpoint
1377 		 */
1378 		/*
1379 		 * write the first SYNCPT record with syncpoint = 0
1380 		 * (i.e., log redo up to HERE !);
1381 		 * remove current page from lbm write queue at end of pageout
1382 		 * (to write log superblock update), but do not release to
1383 		 * freelist;
1384 		 */
1385 		lrd.logtid = 0;
1386 		lrd.backchain = 0;
1387 		lrd.type = cpu_to_le16(LOG_SYNCPT);
1388 		lrd.length = 0;
1389 		lrd.log.syncpt.sync = 0;
1390 		lsn = lmWriteRecord(log, NULL, &lrd, NULL);
1391 		bp = log->bp;
1392 		bp->l_ceor = bp->l_eor;
1393 		lp = (struct logpage *) bp->l_ldata;
1394 		lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
1395 		lbmWrite(log, bp, lbmWRITE | lbmSYNC, 0);
1396 		if ((rc = lbmIOWait(bp, 0)))
1397 			goto errout30;
1398 
1399 		/*
1400 		 * update/write superblock
1401 		 */
1402 		logsuper->state = cpu_to_le32(LOGMOUNT);
1403 		log->serial = le32_to_cpu(logsuper->serial) + 1;
1404 		logsuper->serial = cpu_to_le32(log->serial);
1405 		lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1406 		if ((rc = lbmIOWait(bpsuper, lbmFREE)))
1407 			goto errout30;
1408 	}
1409 
1410 	/* initialize logsync parameters */
1411 	log->logsize = (log->size - 2) << L2LOGPSIZE;
1412 	log->lsn = lsn;
1413 	log->syncpt = lsn;
1414 	log->sync = log->syncpt;
1415 	log->nextsync = LOGSYNC_DELTA(log->logsize);
1416 
1417 	jfs_info("lmLogInit: lsn:0x%x syncpt:0x%x sync:0x%x",
1418 		 log->lsn, log->syncpt, log->sync);
1419 
1420 	/*
1421 	 * initialize for lazy/group commit
1422 	 */
1423 	log->clsn = lsn;
1424 
1425 	return 0;
1426 
1427 	/*
1428 	 *	unwind on error
1429 	 */
1430       errout30:		/* release log page */
1431 	log->wqueue = NULL;
1432 	bp->l_wqnext = NULL;
1433 	lbmFree(bp);
1434 
1435       errout20:		/* release log superblock */
1436 	lbmFree(bpsuper);
1437 
1438       errout10:		/* unwind lbmLogInit() */
1439 	lbmLogShutdown(log);
1440 
1441 	jfs_warn("lmLogInit: exit(%d)", rc);
1442 	return rc;
1443 }
1444 
1445 
1446 /*
1447  * NAME:	lmLogClose()
1448  *
1449  * FUNCTION:	remove file system <ipmnt> from active list of log <iplog>
1450  *		and close it on last close.
1451  *
1452  * PARAMETER:	sb	- superblock
1453  *
1454  * RETURN:	errors from subroutines
1455  *
1456  * serialization:
1457  */
1458 int lmLogClose(struct super_block *sb)
1459 {
1460 	struct jfs_sb_info *sbi = JFS_SBI(sb);
1461 	struct jfs_log *log = sbi->log;
1462 	struct block_device *bdev;
1463 	int rc = 0;
1464 
1465 	jfs_info("lmLogClose: log:0x%p", log);
1466 
1467 	mutex_lock(&jfs_log_mutex);
1468 	LOG_LOCK(log);
1469 	list_del(&sbi->log_list);
1470 	LOG_UNLOCK(log);
1471 	sbi->log = NULL;
1472 
1473 	/*
1474 	 * We need to make sure all of the "written" metapages
1475 	 * actually make it to disk
1476 	 */
1477 	sync_blockdev(sb->s_bdev);
1478 
1479 	if (test_bit(log_INLINELOG, &log->flag)) {
1480 		/*
1481 		 *	in-line log in host file system
1482 		 */
1483 		rc = lmLogShutdown(log);
1484 		kfree(log);
1485 		goto out;
1486 	}
1487 
1488 	if (!log->no_integrity)
1489 		lmLogFileSystem(log, sbi, 0);
1490 
1491 	if (!list_empty(&log->sb_list))
1492 		goto out;
1493 
1494 	/*
1495 	 * TODO: ensure that the dummy_log is in a state to allow
1496 	 * lbmLogShutdown to deallocate all the buffers and call
1497 	 * kfree against dummy_log.  For now, leave dummy_log & its
1498 	 * buffers in memory, and resuse if another no-integrity mount
1499 	 * is requested.
1500 	 */
1501 	if (log->no_integrity)
1502 		goto out;
1503 
1504 	/*
1505 	 *	external log as separate logical volume
1506 	 */
1507 	list_del(&log->journal_list);
1508 	bdev = log->bdev;
1509 	rc = lmLogShutdown(log);
1510 
1511 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1512 
1513 	kfree(log);
1514 
1515       out:
1516 	mutex_unlock(&jfs_log_mutex);
1517 	jfs_info("lmLogClose: exit(%d)", rc);
1518 	return rc;
1519 }
1520 
1521 
1522 /*
1523  * NAME:	jfs_flush_journal()
1524  *
1525  * FUNCTION:	initiate write of any outstanding transactions to the journal
1526  *		and optionally wait until they are all written to disk
1527  *
1528  *		wait == 0  flush until latest txn is committed, don't wait
1529  *		wait == 1  flush until latest txn is committed, wait
1530  *		wait > 1   flush until all txn's are complete, wait
1531  */
1532 void jfs_flush_journal(struct jfs_log *log, int wait)
1533 {
1534 	int i;
1535 	struct tblock *target = NULL;
1536 
1537 	/* jfs_write_inode may call us during read-only mount */
1538 	if (!log)
1539 		return;
1540 
1541 	jfs_info("jfs_flush_journal: log:0x%p wait=%d", log, wait);
1542 
1543 	LOGGC_LOCK(log);
1544 
1545 	if (!list_empty(&log->cqueue)) {
1546 		/*
1547 		 * This ensures that we will keep writing to the journal as long
1548 		 * as there are unwritten commit records
1549 		 */
1550 		target = list_entry(log->cqueue.prev, struct tblock, cqueue);
1551 
1552 		if (test_bit(log_FLUSH, &log->flag)) {
1553 			/*
1554 			 * We're already flushing.
1555 			 * if flush_tblk is NULL, we are flushing everything,
1556 			 * so leave it that way.  Otherwise, update it to the
1557 			 * latest transaction
1558 			 */
1559 			if (log->flush_tblk)
1560 				log->flush_tblk = target;
1561 		} else {
1562 			/* Only flush until latest transaction is committed */
1563 			log->flush_tblk = target;
1564 			set_bit(log_FLUSH, &log->flag);
1565 
1566 			/*
1567 			 * Initiate I/O on outstanding transactions
1568 			 */
1569 			if (!(log->cflag & logGC_PAGEOUT)) {
1570 				log->cflag |= logGC_PAGEOUT;
1571 				lmGCwrite(log, 0);
1572 			}
1573 		}
1574 	}
1575 	if ((wait > 1) || test_bit(log_SYNCBARRIER, &log->flag)) {
1576 		/* Flush until all activity complete */
1577 		set_bit(log_FLUSH, &log->flag);
1578 		log->flush_tblk = NULL;
1579 	}
1580 
1581 	if (wait && target && !(target->flag & tblkGC_COMMITTED)) {
1582 		DECLARE_WAITQUEUE(__wait, current);
1583 
1584 		add_wait_queue(&target->gcwait, &__wait);
1585 		set_current_state(TASK_UNINTERRUPTIBLE);
1586 		LOGGC_UNLOCK(log);
1587 		schedule();
1588 		__set_current_state(TASK_RUNNING);
1589 		LOGGC_LOCK(log);
1590 		remove_wait_queue(&target->gcwait, &__wait);
1591 	}
1592 	LOGGC_UNLOCK(log);
1593 
1594 	if (wait < 2)
1595 		return;
1596 
1597 	write_special_inodes(log, filemap_fdatawrite);
1598 
1599 	/*
1600 	 * If there was recent activity, we may need to wait
1601 	 * for the lazycommit thread to catch up
1602 	 */
1603 	if ((!list_empty(&log->cqueue)) || !list_empty(&log->synclist)) {
1604 		for (i = 0; i < 200; i++) {	/* Too much? */
1605 			msleep(250);
1606 			write_special_inodes(log, filemap_fdatawrite);
1607 			if (list_empty(&log->cqueue) &&
1608 			    list_empty(&log->synclist))
1609 				break;
1610 		}
1611 	}
1612 	assert(list_empty(&log->cqueue));
1613 
1614 #ifdef CONFIG_JFS_DEBUG
1615 	if (!list_empty(&log->synclist)) {
1616 		struct logsyncblk *lp;
1617 
1618 		printk(KERN_ERR "jfs_flush_journal: synclist not empty\n");
1619 		list_for_each_entry(lp, &log->synclist, synclist) {
1620 			if (lp->xflag & COMMIT_PAGE) {
1621 				struct metapage *mp = (struct metapage *)lp;
1622 				print_hex_dump(KERN_ERR, "metapage: ",
1623 					       DUMP_PREFIX_ADDRESS, 16, 4,
1624 					       mp, sizeof(struct metapage), 0);
1625 				print_hex_dump(KERN_ERR, "page: ",
1626 					       DUMP_PREFIX_ADDRESS, 16,
1627 					       sizeof(long), mp->page,
1628 					       sizeof(struct page), 0);
1629 			} else
1630 				print_hex_dump(KERN_ERR, "tblock:",
1631 					       DUMP_PREFIX_ADDRESS, 16, 4,
1632 					       lp, sizeof(struct tblock), 0);
1633 		}
1634 	}
1635 #else
1636 	WARN_ON(!list_empty(&log->synclist));
1637 #endif
1638 	clear_bit(log_FLUSH, &log->flag);
1639 }
1640 
1641 /*
1642  * NAME:	lmLogShutdown()
1643  *
1644  * FUNCTION:	log shutdown at last LogClose().
1645  *
1646  *		write log syncpt record.
1647  *		update super block to set redone flag to 0.
1648  *
1649  * PARAMETER:	log	- log inode
1650  *
1651  * RETURN:	0	- success
1652  *
1653  * serialization: single last close thread
1654  */
1655 int lmLogShutdown(struct jfs_log * log)
1656 {
1657 	int rc;
1658 	struct lrd lrd;
1659 	int lsn;
1660 	struct logsuper *logsuper;
1661 	struct lbuf *bpsuper;
1662 	struct lbuf *bp;
1663 	struct logpage *lp;
1664 
1665 	jfs_info("lmLogShutdown: log:0x%p", log);
1666 
1667 	jfs_flush_journal(log, 2);
1668 
1669 	/*
1670 	 * write the last SYNCPT record with syncpoint = 0
1671 	 * (i.e., log redo up to HERE !)
1672 	 */
1673 	lrd.logtid = 0;
1674 	lrd.backchain = 0;
1675 	lrd.type = cpu_to_le16(LOG_SYNCPT);
1676 	lrd.length = 0;
1677 	lrd.log.syncpt.sync = 0;
1678 
1679 	lsn = lmWriteRecord(log, NULL, &lrd, NULL);
1680 	bp = log->bp;
1681 	lp = (struct logpage *) bp->l_ldata;
1682 	lp->h.eor = lp->t.eor = cpu_to_le16(bp->l_eor);
1683 	lbmWrite(log, log->bp, lbmWRITE | lbmRELEASE | lbmSYNC, 0);
1684 	lbmIOWait(log->bp, lbmFREE);
1685 	log->bp = NULL;
1686 
1687 	/*
1688 	 * synchronous update log superblock
1689 	 * mark log state as shutdown cleanly
1690 	 * (i.e., Log does not need to be replayed).
1691 	 */
1692 	if ((rc = lbmRead(log, 1, &bpsuper)))
1693 		goto out;
1694 
1695 	logsuper = (struct logsuper *) bpsuper->l_ldata;
1696 	logsuper->state = cpu_to_le32(LOGREDONE);
1697 	logsuper->end = cpu_to_le32(lsn);
1698 	lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1699 	rc = lbmIOWait(bpsuper, lbmFREE);
1700 
1701 	jfs_info("lmLogShutdown: lsn:0x%x page:%d eor:%d",
1702 		 lsn, log->page, log->eor);
1703 
1704       out:
1705 	/*
1706 	 * shutdown per log i/o
1707 	 */
1708 	lbmLogShutdown(log);
1709 
1710 	if (rc) {
1711 		jfs_warn("lmLogShutdown: exit(%d)", rc);
1712 	}
1713 	return rc;
1714 }
1715 
1716 
1717 /*
1718  * NAME:	lmLogFileSystem()
1719  *
1720  * FUNCTION:	insert (<activate> = true)/remove (<activate> = false)
1721  *	file system into/from log active file system list.
1722  *
1723  * PARAMETE:	log	- pointer to logs inode.
1724  *		fsdev	- kdev_t of filesystem.
1725  *		serial	- pointer to returned log serial number
1726  *		activate - insert/remove device from active list.
1727  *
1728  * RETURN:	0	- success
1729  *		errors returned by vms_iowait().
1730  */
1731 static int lmLogFileSystem(struct jfs_log * log, struct jfs_sb_info *sbi,
1732 			   int activate)
1733 {
1734 	int rc = 0;
1735 	int i;
1736 	struct logsuper *logsuper;
1737 	struct lbuf *bpsuper;
1738 	char *uuid = sbi->uuid;
1739 
1740 	/*
1741 	 * insert/remove file system device to log active file system list.
1742 	 */
1743 	if ((rc = lbmRead(log, 1, &bpsuper)))
1744 		return rc;
1745 
1746 	logsuper = (struct logsuper *) bpsuper->l_ldata;
1747 	if (activate) {
1748 		for (i = 0; i < MAX_ACTIVE; i++)
1749 			if (!memcmp(logsuper->active[i].uuid, NULL_UUID, 16)) {
1750 				memcpy(logsuper->active[i].uuid, uuid, 16);
1751 				sbi->aggregate = i;
1752 				break;
1753 			}
1754 		if (i == MAX_ACTIVE) {
1755 			jfs_warn("Too many file systems sharing journal!");
1756 			lbmFree(bpsuper);
1757 			return -EMFILE;	/* Is there a better rc? */
1758 		}
1759 	} else {
1760 		for (i = 0; i < MAX_ACTIVE; i++)
1761 			if (!memcmp(logsuper->active[i].uuid, uuid, 16)) {
1762 				memcpy(logsuper->active[i].uuid, NULL_UUID, 16);
1763 				break;
1764 			}
1765 		if (i == MAX_ACTIVE) {
1766 			jfs_warn("Somebody stomped on the journal!");
1767 			lbmFree(bpsuper);
1768 			return -EIO;
1769 		}
1770 
1771 	}
1772 
1773 	/*
1774 	 * synchronous write log superblock:
1775 	 *
1776 	 * write sidestream bypassing write queue:
1777 	 * at file system mount, log super block is updated for
1778 	 * activation of the file system before any log record
1779 	 * (MOUNT record) of the file system, and at file system
1780 	 * unmount, all meta data for the file system has been
1781 	 * flushed before log super block is updated for deactivation
1782 	 * of the file system.
1783 	 */
1784 	lbmDirectWrite(log, bpsuper, lbmWRITE | lbmRELEASE | lbmSYNC);
1785 	rc = lbmIOWait(bpsuper, lbmFREE);
1786 
1787 	return rc;
1788 }
1789 
1790 /*
1791  *		log buffer manager (lbm)
1792  *		------------------------
1793  *
1794  * special purpose buffer manager supporting log i/o requirements.
1795  *
1796  * per log write queue:
1797  * log pageout occurs in serial order by fifo write queue and
1798  * restricting to a single i/o in pregress at any one time.
1799  * a circular singly-linked list
1800  * (log->wrqueue points to the tail, and buffers are linked via
1801  * bp->wrqueue field), and
1802  * maintains log page in pageout ot waiting for pageout in serial pageout.
1803  */
1804 
1805 /*
1806  *	lbmLogInit()
1807  *
1808  * initialize per log I/O setup at lmLogInit()
1809  */
1810 static int lbmLogInit(struct jfs_log * log)
1811 {				/* log inode */
1812 	int i;
1813 	struct lbuf *lbuf;
1814 
1815 	jfs_info("lbmLogInit: log:0x%p", log);
1816 
1817 	/* initialize current buffer cursor */
1818 	log->bp = NULL;
1819 
1820 	/* initialize log device write queue */
1821 	log->wqueue = NULL;
1822 
1823 	/*
1824 	 * Each log has its own buffer pages allocated to it.  These are
1825 	 * not managed by the page cache.  This ensures that a transaction
1826 	 * writing to the log does not block trying to allocate a page from
1827 	 * the page cache (for the log).  This would be bad, since page
1828 	 * allocation waits on the kswapd thread that may be committing inodes
1829 	 * which would cause log activity.  Was that clear?  I'm trying to
1830 	 * avoid deadlock here.
1831 	 */
1832 	init_waitqueue_head(&log->free_wait);
1833 
1834 	log->lbuf_free = NULL;
1835 
1836 	for (i = 0; i < LOGPAGES;) {
1837 		char *buffer;
1838 		uint offset;
1839 		struct page *page;
1840 
1841 		buffer = (char *) get_zeroed_page(GFP_KERNEL);
1842 		if (buffer == NULL)
1843 			goto error;
1844 		page = virt_to_page(buffer);
1845 		for (offset = 0; offset < PAGE_SIZE; offset += LOGPSIZE) {
1846 			lbuf = kmalloc(sizeof(struct lbuf), GFP_KERNEL);
1847 			if (lbuf == NULL) {
1848 				if (offset == 0)
1849 					free_page((unsigned long) buffer);
1850 				goto error;
1851 			}
1852 			if (offset) /* we already have one reference */
1853 				get_page(page);
1854 			lbuf->l_offset = offset;
1855 			lbuf->l_ldata = buffer + offset;
1856 			lbuf->l_page = page;
1857 			lbuf->l_log = log;
1858 			init_waitqueue_head(&lbuf->l_ioevent);
1859 
1860 			lbuf->l_freelist = log->lbuf_free;
1861 			log->lbuf_free = lbuf;
1862 			i++;
1863 		}
1864 	}
1865 
1866 	return (0);
1867 
1868       error:
1869 	lbmLogShutdown(log);
1870 	return -ENOMEM;
1871 }
1872 
1873 
1874 /*
1875  *	lbmLogShutdown()
1876  *
1877  * finalize per log I/O setup at lmLogShutdown()
1878  */
1879 static void lbmLogShutdown(struct jfs_log * log)
1880 {
1881 	struct lbuf *lbuf;
1882 
1883 	jfs_info("lbmLogShutdown: log:0x%p", log);
1884 
1885 	lbuf = log->lbuf_free;
1886 	while (lbuf) {
1887 		struct lbuf *next = lbuf->l_freelist;
1888 		__free_page(lbuf->l_page);
1889 		kfree(lbuf);
1890 		lbuf = next;
1891 	}
1892 }
1893 
1894 
1895 /*
1896  *	lbmAllocate()
1897  *
1898  * allocate an empty log buffer
1899  */
1900 static struct lbuf *lbmAllocate(struct jfs_log * log, int pn)
1901 {
1902 	struct lbuf *bp;
1903 	unsigned long flags;
1904 
1905 	/*
1906 	 * recycle from log buffer freelist if any
1907 	 */
1908 	LCACHE_LOCK(flags);
1909 	LCACHE_SLEEP_COND(log->free_wait, (bp = log->lbuf_free), flags);
1910 	log->lbuf_free = bp->l_freelist;
1911 	LCACHE_UNLOCK(flags);
1912 
1913 	bp->l_flag = 0;
1914 
1915 	bp->l_wqnext = NULL;
1916 	bp->l_freelist = NULL;
1917 
1918 	bp->l_pn = pn;
1919 	bp->l_blkno = log->base + (pn << (L2LOGPSIZE - log->l2bsize));
1920 	bp->l_ceor = 0;
1921 
1922 	return bp;
1923 }
1924 
1925 
1926 /*
1927  *	lbmFree()
1928  *
1929  * release a log buffer to freelist
1930  */
1931 static void lbmFree(struct lbuf * bp)
1932 {
1933 	unsigned long flags;
1934 
1935 	LCACHE_LOCK(flags);
1936 
1937 	lbmfree(bp);
1938 
1939 	LCACHE_UNLOCK(flags);
1940 }
1941 
1942 static void lbmfree(struct lbuf * bp)
1943 {
1944 	struct jfs_log *log = bp->l_log;
1945 
1946 	assert(bp->l_wqnext == NULL);
1947 
1948 	/*
1949 	 * return the buffer to head of freelist
1950 	 */
1951 	bp->l_freelist = log->lbuf_free;
1952 	log->lbuf_free = bp;
1953 
1954 	wake_up(&log->free_wait);
1955 	return;
1956 }
1957 
1958 
1959 /*
1960  * NAME:	lbmRedrive
1961  *
1962  * FUNCTION:	add a log buffer to the log redrive list
1963  *
1964  * PARAMETER:
1965  *	bp	- log buffer
1966  *
1967  * NOTES:
1968  *	Takes log_redrive_lock.
1969  */
1970 static inline void lbmRedrive(struct lbuf *bp)
1971 {
1972 	unsigned long flags;
1973 
1974 	spin_lock_irqsave(&log_redrive_lock, flags);
1975 	bp->l_redrive_next = log_redrive_list;
1976 	log_redrive_list = bp;
1977 	spin_unlock_irqrestore(&log_redrive_lock, flags);
1978 
1979 	wake_up_process(jfsIOthread);
1980 }
1981 
1982 
1983 /*
1984  *	lbmRead()
1985  */
1986 static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
1987 {
1988 	struct bio *bio;
1989 	struct lbuf *bp;
1990 
1991 	/*
1992 	 * allocate a log buffer
1993 	 */
1994 	*bpp = bp = lbmAllocate(log, pn);
1995 	jfs_info("lbmRead: bp:0x%p pn:0x%x", bp, pn);
1996 
1997 	bp->l_flag |= lbmREAD;
1998 
1999 	bio = bio_alloc(GFP_NOFS, 1);
2000 
2001 	bio->bi_iter.bi_sector = bp->l_blkno << (log->l2bsize - 9);
2002 	bio->bi_bdev = log->bdev;
2003 	bio->bi_io_vec[0].bv_page = bp->l_page;
2004 	bio->bi_io_vec[0].bv_len = LOGPSIZE;
2005 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
2006 
2007 	bio->bi_vcnt = 1;
2008 	bio->bi_iter.bi_size = LOGPSIZE;
2009 
2010 	bio->bi_end_io = lbmIODone;
2011 	bio->bi_private = bp;
2012 	/*check if journaling to disk has been disabled*/
2013 	if (log->no_integrity) {
2014 		bio->bi_iter.bi_size = 0;
2015 		lbmIODone(bio, 0);
2016 	} else {
2017 		submit_bio(READ_SYNC, bio);
2018 	}
2019 
2020 	wait_event(bp->l_ioevent, (bp->l_flag != lbmREAD));
2021 
2022 	return 0;
2023 }
2024 
2025 
2026 /*
2027  *	lbmWrite()
2028  *
2029  * buffer at head of pageout queue stays after completion of
2030  * partial-page pageout and redriven by explicit initiation of
2031  * pageout by caller until full-page pageout is completed and
2032  * released.
2033  *
2034  * device driver i/o done redrives pageout of new buffer at
2035  * head of pageout queue when current buffer at head of pageout
2036  * queue is released at the completion of its full-page pageout.
2037  *
2038  * LOGGC_LOCK() serializes lbmWrite() by lmNextPage() and lmGroupCommit().
2039  * LCACHE_LOCK() serializes xflag between lbmWrite() and lbmIODone()
2040  */
2041 static void lbmWrite(struct jfs_log * log, struct lbuf * bp, int flag,
2042 		     int cant_block)
2043 {
2044 	struct lbuf *tail;
2045 	unsigned long flags;
2046 
2047 	jfs_info("lbmWrite: bp:0x%p flag:0x%x pn:0x%x", bp, flag, bp->l_pn);
2048 
2049 	/* map the logical block address to physical block address */
2050 	bp->l_blkno =
2051 	    log->base + (bp->l_pn << (L2LOGPSIZE - log->l2bsize));
2052 
2053 	LCACHE_LOCK(flags);		/* disable+lock */
2054 
2055 	/*
2056 	 * initialize buffer for device driver
2057 	 */
2058 	bp->l_flag = flag;
2059 
2060 	/*
2061 	 *	insert bp at tail of write queue associated with log
2062 	 *
2063 	 * (request is either for bp already/currently at head of queue
2064 	 * or new bp to be inserted at tail)
2065 	 */
2066 	tail = log->wqueue;
2067 
2068 	/* is buffer not already on write queue ? */
2069 	if (bp->l_wqnext == NULL) {
2070 		/* insert at tail of wqueue */
2071 		if (tail == NULL) {
2072 			log->wqueue = bp;
2073 			bp->l_wqnext = bp;
2074 		} else {
2075 			log->wqueue = bp;
2076 			bp->l_wqnext = tail->l_wqnext;
2077 			tail->l_wqnext = bp;
2078 		}
2079 
2080 		tail = bp;
2081 	}
2082 
2083 	/* is buffer at head of wqueue and for write ? */
2084 	if ((bp != tail->l_wqnext) || !(flag & lbmWRITE)) {
2085 		LCACHE_UNLOCK(flags);	/* unlock+enable */
2086 		return;
2087 	}
2088 
2089 	LCACHE_UNLOCK(flags);	/* unlock+enable */
2090 
2091 	if (cant_block)
2092 		lbmRedrive(bp);
2093 	else if (flag & lbmSYNC)
2094 		lbmStartIO(bp);
2095 	else {
2096 		LOGGC_UNLOCK(log);
2097 		lbmStartIO(bp);
2098 		LOGGC_LOCK(log);
2099 	}
2100 }
2101 
2102 
2103 /*
2104  *	lbmDirectWrite()
2105  *
2106  * initiate pageout bypassing write queue for sidestream
2107  * (e.g., log superblock) write;
2108  */
2109 static void lbmDirectWrite(struct jfs_log * log, struct lbuf * bp, int flag)
2110 {
2111 	jfs_info("lbmDirectWrite: bp:0x%p flag:0x%x pn:0x%x",
2112 		 bp, flag, bp->l_pn);
2113 
2114 	/*
2115 	 * initialize buffer for device driver
2116 	 */
2117 	bp->l_flag = flag | lbmDIRECT;
2118 
2119 	/* map the logical block address to physical block address */
2120 	bp->l_blkno =
2121 	    log->base + (bp->l_pn << (L2LOGPSIZE - log->l2bsize));
2122 
2123 	/*
2124 	 *	initiate pageout of the page
2125 	 */
2126 	lbmStartIO(bp);
2127 }
2128 
2129 
2130 /*
2131  * NAME:	lbmStartIO()
2132  *
2133  * FUNCTION:	Interface to DD strategy routine
2134  *
2135  * RETURN:	none
2136  *
2137  * serialization: LCACHE_LOCK() is NOT held during log i/o;
2138  */
2139 static void lbmStartIO(struct lbuf * bp)
2140 {
2141 	struct bio *bio;
2142 	struct jfs_log *log = bp->l_log;
2143 
2144 	jfs_info("lbmStartIO\n");
2145 
2146 	bio = bio_alloc(GFP_NOFS, 1);
2147 	bio->bi_iter.bi_sector = bp->l_blkno << (log->l2bsize - 9);
2148 	bio->bi_bdev = log->bdev;
2149 	bio->bi_io_vec[0].bv_page = bp->l_page;
2150 	bio->bi_io_vec[0].bv_len = LOGPSIZE;
2151 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
2152 
2153 	bio->bi_vcnt = 1;
2154 	bio->bi_iter.bi_size = LOGPSIZE;
2155 
2156 	bio->bi_end_io = lbmIODone;
2157 	bio->bi_private = bp;
2158 
2159 	/* check if journaling to disk has been disabled */
2160 	if (log->no_integrity) {
2161 		bio->bi_iter.bi_size = 0;
2162 		lbmIODone(bio, 0);
2163 	} else {
2164 		submit_bio(WRITE_SYNC, bio);
2165 		INCREMENT(lmStat.submitted);
2166 	}
2167 }
2168 
2169 
2170 /*
2171  *	lbmIOWait()
2172  */
2173 static int lbmIOWait(struct lbuf * bp, int flag)
2174 {
2175 	unsigned long flags;
2176 	int rc = 0;
2177 
2178 	jfs_info("lbmIOWait1: bp:0x%p flag:0x%x:0x%x", bp, bp->l_flag, flag);
2179 
2180 	LCACHE_LOCK(flags);		/* disable+lock */
2181 
2182 	LCACHE_SLEEP_COND(bp->l_ioevent, (bp->l_flag & lbmDONE), flags);
2183 
2184 	rc = (bp->l_flag & lbmERROR) ? -EIO : 0;
2185 
2186 	if (flag & lbmFREE)
2187 		lbmfree(bp);
2188 
2189 	LCACHE_UNLOCK(flags);	/* unlock+enable */
2190 
2191 	jfs_info("lbmIOWait2: bp:0x%p flag:0x%x:0x%x", bp, bp->l_flag, flag);
2192 	return rc;
2193 }
2194 
2195 /*
2196  *	lbmIODone()
2197  *
2198  * executed at INTIODONE level
2199  */
2200 static void lbmIODone(struct bio *bio, int error)
2201 {
2202 	struct lbuf *bp = bio->bi_private;
2203 	struct lbuf *nextbp, *tail;
2204 	struct jfs_log *log;
2205 	unsigned long flags;
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;
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;
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 
2341 int jfsIOWait(void *arg)
2342 {
2343 	struct lbuf *bp;
2344 
2345 	do {
2346 		spin_lock_irq(&log_redrive_lock);
2347 		while ((bp = log_redrive_list)) {
2348 			log_redrive_list = bp->l_redrive_next;
2349 			bp->l_redrive_next = NULL;
2350 			spin_unlock_irq(&log_redrive_lock);
2351 			lbmStartIO(bp);
2352 			spin_lock_irq(&log_redrive_lock);
2353 		}
2354 
2355 		if (freezing(current)) {
2356 			spin_unlock_irq(&log_redrive_lock);
2357 			try_to_freeze();
2358 		} else {
2359 			set_current_state(TASK_INTERRUPTIBLE);
2360 			spin_unlock_irq(&log_redrive_lock);
2361 			schedule();
2362 			__set_current_state(TASK_RUNNING);
2363 		}
2364 	} while (!kthread_should_stop());
2365 
2366 	jfs_info("jfsIOWait being killed!");
2367 	return 0;
2368 }
2369 
2370 /*
2371  * NAME:	lmLogFormat()/jfs_logform()
2372  *
2373  * FUNCTION:	format file system log
2374  *
2375  * PARAMETERS:
2376  *	log	- volume log
2377  *	logAddress - start address of log space in FS block
2378  *	logSize	- length of log space in FS block;
2379  *
2380  * RETURN:	0	- success
2381  *		-EIO	- i/o error
2382  *
2383  * XXX: We're synchronously writing one page at a time.  This needs to
2384  *	be improved by writing multiple pages at once.
2385  */
2386 int lmLogFormat(struct jfs_log *log, s64 logAddress, int logSize)
2387 {
2388 	int rc = -EIO;
2389 	struct jfs_sb_info *sbi;
2390 	struct logsuper *logsuper;
2391 	struct logpage *lp;
2392 	int lspn;		/* log sequence page number */
2393 	struct lrd *lrd_ptr;
2394 	int npages = 0;
2395 	struct lbuf *bp;
2396 
2397 	jfs_info("lmLogFormat: logAddress:%Ld logSize:%d",
2398 		 (long long)logAddress, logSize);
2399 
2400 	sbi = list_entry(log->sb_list.next, struct jfs_sb_info, log_list);
2401 
2402 	/* allocate a log buffer */
2403 	bp = lbmAllocate(log, 1);
2404 
2405 	npages = logSize >> sbi->l2nbperpage;
2406 
2407 	/*
2408 	 *	log space:
2409 	 *
2410 	 * page 0 - reserved;
2411 	 * page 1 - log superblock;
2412 	 * page 2 - log data page: A SYNC log record is written
2413 	 *	    into this page at logform time;
2414 	 * pages 3-N - log data page: set to empty log data pages;
2415 	 */
2416 	/*
2417 	 *	init log superblock: log page 1
2418 	 */
2419 	logsuper = (struct logsuper *) bp->l_ldata;
2420 
2421 	logsuper->magic = cpu_to_le32(LOGMAGIC);
2422 	logsuper->version = cpu_to_le32(LOGVERSION);
2423 	logsuper->state = cpu_to_le32(LOGREDONE);
2424 	logsuper->flag = cpu_to_le32(sbi->mntflag);	/* ? */
2425 	logsuper->size = cpu_to_le32(npages);
2426 	logsuper->bsize = cpu_to_le32(sbi->bsize);
2427 	logsuper->l2bsize = cpu_to_le32(sbi->l2bsize);
2428 	logsuper->end = cpu_to_le32(2 * LOGPSIZE + LOGPHDRSIZE + LOGRDSIZE);
2429 
2430 	bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
2431 	bp->l_blkno = logAddress + sbi->nbperpage;
2432 	lbmStartIO(bp);
2433 	if ((rc = lbmIOWait(bp, 0)))
2434 		goto exit;
2435 
2436 	/*
2437 	 *	init pages 2 to npages-1 as log data pages:
2438 	 *
2439 	 * log page sequence number (lpsn) initialization:
2440 	 *
2441 	 * pn:   0     1     2     3                 n-1
2442 	 *       +-----+-----+=====+=====+===.....===+=====+
2443 	 * lspn:             N-1   0     1           N-2
2444 	 *                   <--- N page circular file ---->
2445 	 *
2446 	 * the N (= npages-2) data pages of the log is maintained as
2447 	 * a circular file for the log records;
2448 	 * lpsn grows by 1 monotonically as each log page is written
2449 	 * to the circular file of the log;
2450 	 * and setLogpage() will not reset the page number even if
2451 	 * the eor is equal to LOGPHDRSIZE. In order for binary search
2452 	 * still work in find log end process, we have to simulate the
2453 	 * log wrap situation at the log format time.
2454 	 * The 1st log page written will have the highest lpsn. Then
2455 	 * the succeeding log pages will have ascending order of
2456 	 * the lspn starting from 0, ... (N-2)
2457 	 */
2458 	lp = (struct logpage *) bp->l_ldata;
2459 	/*
2460 	 * initialize 1st log page to be written: lpsn = N - 1,
2461 	 * write a SYNCPT log record is written to this page
2462 	 */
2463 	lp->h.page = lp->t.page = cpu_to_le32(npages - 3);
2464 	lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE + LOGRDSIZE);
2465 
2466 	lrd_ptr = (struct lrd *) &lp->data;
2467 	lrd_ptr->logtid = 0;
2468 	lrd_ptr->backchain = 0;
2469 	lrd_ptr->type = cpu_to_le16(LOG_SYNCPT);
2470 	lrd_ptr->length = 0;
2471 	lrd_ptr->log.syncpt.sync = 0;
2472 
2473 	bp->l_blkno += sbi->nbperpage;
2474 	bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
2475 	lbmStartIO(bp);
2476 	if ((rc = lbmIOWait(bp, 0)))
2477 		goto exit;
2478 
2479 	/*
2480 	 *	initialize succeeding log pages: lpsn = 0, 1, ..., (N-2)
2481 	 */
2482 	for (lspn = 0; lspn < npages - 3; lspn++) {
2483 		lp->h.page = lp->t.page = cpu_to_le32(lspn);
2484 		lp->h.eor = lp->t.eor = cpu_to_le16(LOGPHDRSIZE);
2485 
2486 		bp->l_blkno += sbi->nbperpage;
2487 		bp->l_flag = lbmWRITE | lbmSYNC | lbmDIRECT;
2488 		lbmStartIO(bp);
2489 		if ((rc = lbmIOWait(bp, 0)))
2490 			goto exit;
2491 	}
2492 
2493 	rc = 0;
2494 exit:
2495 	/*
2496 	 *	finalize log
2497 	 */
2498 	/* release the buffer */
2499 	lbmFree(bp);
2500 
2501 	return rc;
2502 }
2503 
2504 #ifdef CONFIG_JFS_STATISTICS
2505 static int jfs_lmstats_proc_show(struct seq_file *m, void *v)
2506 {
2507 	seq_printf(m,
2508 		       "JFS Logmgr stats\n"
2509 		       "================\n"
2510 		       "commits = %d\n"
2511 		       "writes submitted = %d\n"
2512 		       "writes completed = %d\n"
2513 		       "full pages submitted = %d\n"
2514 		       "partial pages submitted = %d\n",
2515 		       lmStat.commit,
2516 		       lmStat.submitted,
2517 		       lmStat.pagedone,
2518 		       lmStat.full_page,
2519 		       lmStat.partial_page);
2520 	return 0;
2521 }
2522 
2523 static int jfs_lmstats_proc_open(struct inode *inode, struct file *file)
2524 {
2525 	return single_open(file, jfs_lmstats_proc_show, NULL);
2526 }
2527 
2528 const struct file_operations jfs_lmstats_proc_fops = {
2529 	.owner		= THIS_MODULE,
2530 	.open		= jfs_lmstats_proc_open,
2531 	.read		= seq_read,
2532 	.llseek		= seq_lseek,
2533 	.release	= single_release,
2534 };
2535 #endif /* CONFIG_JFS_STATISTICS */
2536