1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *   Copyright (C) International Business Machines Corp., 2000-2005
  4 *   Portions Copyright (C) Christoph Hellwig, 2001-2002
  5 */
  6
  7#include <linux/fs.h>
  8#include <linux/mm.h>
  9#include <linux/module.h>
 10#include <linux/bio.h>
 11#include <linux/slab.h>
 12#include <linux/init.h>
 13#include <linux/buffer_head.h>
 14#include <linux/mempool.h>
 15#include <linux/seq_file.h>
 16#include "jfs_incore.h"
 17#include "jfs_superblock.h"
 18#include "jfs_filsys.h"
 19#include "jfs_metapage.h"
 20#include "jfs_txnmgr.h"
 21#include "jfs_debug.h"
 22
 23#ifdef CONFIG_JFS_STATISTICS
 24static struct {
 25	uint	pagealloc;	/* # of page allocations */
 26	uint	pagefree;	/* # of page frees */
 27	uint	lockwait;	/* # of sleeping lock_metapage() calls */
 28} mpStat;
 29#endif
 30
 31#define metapage_locked(mp) test_bit(META_locked, &(mp)->flag)
 32#define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag)
 33
 34static inline void unlock_metapage(struct metapage *mp)
 35{
 36	clear_bit_unlock(META_locked, &mp->flag);
 37	wake_up(&mp->wait);
 38}
 39
 40static inline void __lock_metapage(struct metapage *mp)
 41{
 42	DECLARE_WAITQUEUE(wait, current);
 43	INCREMENT(mpStat.lockwait);
 44	add_wait_queue_exclusive(&mp->wait, &wait);
 45	do {
 46		set_current_state(TASK_UNINTERRUPTIBLE);
 47		if (metapage_locked(mp)) {
 48			unlock_page(mp->page);
 49			io_schedule();
 50			lock_page(mp->page);
 51		}
 52	} while (trylock_metapage(mp));
 53	__set_current_state(TASK_RUNNING);
 54	remove_wait_queue(&mp->wait, &wait);
 55}
 56
 57/*
 58 * Must have mp->page locked
 59 */
 60static inline void lock_metapage(struct metapage *mp)
 61{
 62	if (trylock_metapage(mp))
 63		__lock_metapage(mp);
 64}
 65
 66#define METAPOOL_MIN_PAGES 32
 67static struct kmem_cache *metapage_cache;
 68static mempool_t *metapage_mempool;
 69
 70#define MPS_PER_PAGE (PAGE_SIZE >> L2PSIZE)
 71
 72#if MPS_PER_PAGE > 1
 73
 74struct meta_anchor {
 75	int mp_count;
 76	atomic_t io_count;
 77	struct metapage *mp[MPS_PER_PAGE];
 78};
 79#define mp_anchor(page) ((struct meta_anchor *)page_private(page))
 80
 81static inline struct metapage *page_to_mp(struct page *page, int offset)
 82{
 83	if (!PagePrivate(page))
 84		return NULL;
 85	return mp_anchor(page)->mp[offset >> L2PSIZE];
 86}
 87
 88static inline int insert_metapage(struct page *page, struct metapage *mp)
 89{
 90	struct meta_anchor *a;
 91	int index;
 92	int l2mp_blocks;	/* log2 blocks per metapage */
 93
 94	if (PagePrivate(page))
 95		a = mp_anchor(page);
 96	else {
 97		a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS);
 98		if (!a)
 99			return -ENOMEM;
100		set_page_private(page, (unsigned long)a);
101		SetPagePrivate(page);
102		kmap(page);
103	}
104
105	if (mp) {
106		l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
107		index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
108		a->mp_count++;
109		a->mp[index] = mp;
110	}
111
112	return 0;
113}
114
115static inline void remove_metapage(struct page *page, struct metapage *mp)
116{
117	struct meta_anchor *a = mp_anchor(page);
118	int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
119	int index;
120
121	index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
122
123	BUG_ON(a->mp[index] != mp);
124
125	a->mp[index] = NULL;
126	if (--a->mp_count == 0) {
127		kfree(a);
128		set_page_private(page, 0);
129		ClearPagePrivate(page);
130		kunmap(page);
131	}
132}
133
134static inline void inc_io(struct page *page)
135{
136	atomic_inc(&mp_anchor(page)->io_count);
137}
138
139static inline void dec_io(struct page *page, void (*handler) (struct page *))
140{
141	if (atomic_dec_and_test(&mp_anchor(page)->io_count))
142		handler(page);
143}
144
145#else
146static inline struct metapage *page_to_mp(struct page *page, int offset)
147{
148	return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL;
149}
150
151static inline int insert_metapage(struct page *page, struct metapage *mp)
152{
153	if (mp) {
154		set_page_private(page, (unsigned long)mp);
155		SetPagePrivate(page);
156		kmap(page);
157	}
158	return 0;
159}
160
161static inline void remove_metapage(struct page *page, struct metapage *mp)
162{
163	set_page_private(page, 0);
164	ClearPagePrivate(page);
165	kunmap(page);
166}
167
168#define inc_io(page) do {} while(0)
169#define dec_io(page, handler) handler(page)
170
171#endif
172
173static inline struct metapage *alloc_metapage(gfp_t gfp_mask)
174{
175	struct metapage *mp = mempool_alloc(metapage_mempool, gfp_mask);
176
177	if (mp) {
178		mp->lid = 0;
179		mp->lsn = 0;
180		mp->data = NULL;
181		mp->clsn = 0;
182		mp->log = NULL;
183		init_waitqueue_head(&mp->wait);
184	}
185	return mp;
186}
187
188static inline void free_metapage(struct metapage *mp)
189{
190	mempool_free(mp, metapage_mempool);
191}
192
193int __init metapage_init(void)
194{
195	/*
196	 * Allocate the metapage structures
197	 */
198	metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage),
199					   0, 0, NULL);
200	if (metapage_cache == NULL)
201		return -ENOMEM;
202
203	metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES,
204						    metapage_cache);
205
206	if (metapage_mempool == NULL) {
207		kmem_cache_destroy(metapage_cache);
208		return -ENOMEM;
209	}
210
211	return 0;
212}
213
214void metapage_exit(void)
215{
216	mempool_destroy(metapage_mempool);
217	kmem_cache_destroy(metapage_cache);
218}
219
220static inline void drop_metapage(struct page *page, struct metapage *mp)
221{
222	if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) ||
223	    test_bit(META_io, &mp->flag))
224		return;
225	remove_metapage(page, mp);
226	INCREMENT(mpStat.pagefree);
227	free_metapage(mp);
228}
229
230/*
231 * Metapage address space operations
232 */
233
234static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
235				    int *len)
236{
237	int rc = 0;
238	int xflag;
239	s64 xaddr;
240	sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
241			       inode->i_blkbits;
242
243	if (lblock >= file_blocks)
244		return 0;
245	if (lblock + *len > file_blocks)
246		*len = file_blocks - lblock;
247
248	if (inode->i_ino) {
249		rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0);
250		if ((rc == 0) && *len)
251			lblock = (sector_t)xaddr;
252		else
253			lblock = 0;
254	} /* else no mapping */
255
256	return lblock;
257}
258
259static void last_read_complete(struct page *page)
260{
261	if (!PageError(page))
262		SetPageUptodate(page);
263	unlock_page(page);
264}
265
266static void metapage_read_end_io(struct bio *bio)
267{
268	struct page *page = bio->bi_private;
269
270	if (bio->bi_status) {
271		printk(KERN_ERR "metapage_read_end_io: I/O error\n");
272		SetPageError(page);
273	}
274
275	dec_io(page, last_read_complete);
276	bio_put(bio);
277}
278
279static void remove_from_logsync(struct metapage *mp)
280{
281	struct jfs_log *log = mp->log;
282	unsigned long flags;
283/*
284 * This can race.  Recheck that log hasn't been set to null, and after
285 * acquiring logsync lock, recheck lsn
286 */
287	if (!log)
288		return;
289
290	LOGSYNC_LOCK(log, flags);
291	if (mp->lsn) {
292		mp->log = NULL;
293		mp->lsn = 0;
294		mp->clsn = 0;
295		log->count--;
296		list_del(&mp->synclist);
297	}
298	LOGSYNC_UNLOCK(log, flags);
299}
300
301static void last_write_complete(struct page *page)
302{
303	struct metapage *mp;
304	unsigned int offset;
305
306	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
307		mp = page_to_mp(page, offset);
308		if (mp && test_bit(META_io, &mp->flag)) {
309			if (mp->lsn)
310				remove_from_logsync(mp);
311			clear_bit(META_io, &mp->flag);
312		}
313		/*
314		 * I'd like to call drop_metapage here, but I don't think it's
315		 * safe unless I have the page locked
316		 */
317	}
318	end_page_writeback(page);
319}
320
321static void metapage_write_end_io(struct bio *bio)
322{
323	struct page *page = bio->bi_private;
324
325	BUG_ON(!PagePrivate(page));
326
327	if (bio->bi_status) {
328		printk(KERN_ERR "metapage_write_end_io: I/O error\n");
329		SetPageError(page);
330	}
331	dec_io(page, last_write_complete);
332	bio_put(bio);
333}
334
335static int metapage_writepage(struct page *page, struct writeback_control *wbc)
336{
337	struct bio *bio = NULL;
338	int block_offset;	/* block offset of mp within page */
339	struct inode *inode = page->mapping->host;
340	int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
341	int len;
342	int xlen;
343	struct metapage *mp;
344	int redirty = 0;
345	sector_t lblock;
346	int nr_underway = 0;
347	sector_t pblock;
348	sector_t next_block = 0;
349	sector_t page_start;
350	unsigned long bio_bytes = 0;
351	unsigned long bio_offset = 0;
352	int offset;
353	int bad_blocks = 0;
354
355	page_start = (sector_t)page->index <<
356		     (PAGE_SHIFT - inode->i_blkbits);
357	BUG_ON(!PageLocked(page));
358	BUG_ON(PageWriteback(page));
359	set_page_writeback(page);
360
361	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
362		mp = page_to_mp(page, offset);
363
364		if (!mp || !test_bit(META_dirty, &mp->flag))
365			continue;
366
367		if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) {
368			redirty = 1;
369			/*
370			 * Make sure this page isn't blocked indefinitely.
371			 * If the journal isn't undergoing I/O, push it
372			 */
373			if (mp->log && !(mp->log->cflag & logGC_PAGEOUT))
374				jfs_flush_journal(mp->log, 0);
375			continue;
376		}
377
378		clear_bit(META_dirty, &mp->flag);
379		set_bit(META_io, &mp->flag);
380		block_offset = offset >> inode->i_blkbits;
381		lblock = page_start + block_offset;
382		if (bio) {
383			if (xlen && lblock == next_block) {
384				/* Contiguous, in memory & on disk */
385				len = min(xlen, blocks_per_mp);
386				xlen -= len;
387				bio_bytes += len << inode->i_blkbits;
388				continue;
389			}
390			/* Not contiguous */
391			if (bio_add_page(bio, page, bio_bytes, bio_offset) <
392			    bio_bytes)
393				goto add_failed;
394			/*
395			 * Increment counter before submitting i/o to keep
396			 * count from hitting zero before we're through
397			 */
398			inc_io(page);
399			if (!bio->bi_iter.bi_size)
400				goto dump_bio;
401			submit_bio(bio);
402			nr_underway++;
403			bio = NULL;
404		} else
405			inc_io(page);
406		xlen = (PAGE_SIZE - offset) >> inode->i_blkbits;
407		pblock = metapage_get_blocks(inode, lblock, &xlen);
408		if (!pblock) {
409			printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
410			/*
411			 * We already called inc_io(), but can't cancel it
412			 * with dec_io() until we're done with the page
413			 */
414			bad_blocks++;
415			continue;
416		}
417		len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage);
418
419		bio = bio_alloc(GFP_NOFS, 1);
420		bio_set_dev(bio, inode->i_sb->s_bdev);
421		bio->bi_iter.bi_sector = pblock << (inode->i_blkbits - 9);
422		bio->bi_end_io = metapage_write_end_io;
423		bio->bi_private = page;
424		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
425
426		/* Don't call bio_add_page yet, we may add to this vec */
427		bio_offset = offset;
428		bio_bytes = len << inode->i_blkbits;
429
430		xlen -= len;
431		next_block = lblock + len;
432	}
433	if (bio) {
434		if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
435				goto add_failed;
436		if (!bio->bi_iter.bi_size)
437			goto dump_bio;
438
439		submit_bio(bio);
440		nr_underway++;
441	}
442	if (redirty)
443		redirty_page_for_writepage(wbc, page);
444
445	unlock_page(page);
446
447	if (bad_blocks)
448		goto err_out;
449
450	if (nr_underway == 0)
451		end_page_writeback(page);
452
453	return 0;
454add_failed:
455	/* We should never reach here, since we're only adding one vec */
456	printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
457	goto skip;
458dump_bio:
459	print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16,
460		       4, bio, sizeof(*bio), 0);
461skip:
462	bio_put(bio);
463	unlock_page(page);
464	dec_io(page, last_write_complete);
465err_out:
466	while (bad_blocks--)
467		dec_io(page, last_write_complete);
468	return -EIO;
469}
470
471static int metapage_readpage(struct file *fp, struct page *page)
472{
473	struct inode *inode = page->mapping->host;
474	struct bio *bio = NULL;
475	int block_offset;
476	int blocks_per_page = PAGE_SIZE >> inode->i_blkbits;
477	sector_t page_start;	/* address of page in fs blocks */
478	sector_t pblock;
479	int xlen;
480	unsigned int len;
481	int offset;
482
483	BUG_ON(!PageLocked(page));
484	page_start = (sector_t)page->index <<
485		     (PAGE_SHIFT - inode->i_blkbits);
486
487	block_offset = 0;
488	while (block_offset < blocks_per_page) {
489		xlen = blocks_per_page - block_offset;
490		pblock = metapage_get_blocks(inode, page_start + block_offset,
491					     &xlen);
492		if (pblock) {
493			if (!PagePrivate(page))
494				insert_metapage(page, NULL);
495			inc_io(page);
496			if (bio)
497				submit_bio(bio);
498
499			bio = bio_alloc(GFP_NOFS, 1);
500			bio_set_dev(bio, inode->i_sb->s_bdev);
501			bio->bi_iter.bi_sector =
502				pblock << (inode->i_blkbits - 9);
503			bio->bi_end_io = metapage_read_end_io;
504			bio->bi_private = page;
505			bio_set_op_attrs(bio, REQ_OP_READ, 0);
506			len = xlen << inode->i_blkbits;
507			offset = block_offset << inode->i_blkbits;
508			if (bio_add_page(bio, page, len, offset) < len)
509				goto add_failed;
510			block_offset += xlen;
511		} else
512			block_offset++;
513	}
514	if (bio)
515		submit_bio(bio);
516	else
517		unlock_page(page);
518
519	return 0;
520
521add_failed:
522	printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
523	bio_put(bio);
524	dec_io(page, last_read_complete);
525	return -EIO;
526}
527
528static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
529{
530	struct metapage *mp;
531	int ret = 1;
532	int offset;
533
534	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
535		mp = page_to_mp(page, offset);
536
537		if (!mp)
538			continue;
539
540		jfs_info("metapage_releasepage: mp = 0x%p", mp);
541		if (mp->count || mp->nohomeok ||
542		    test_bit(META_dirty, &mp->flag)) {
543			jfs_info("count = %ld, nohomeok = %d", mp->count,
544				 mp->nohomeok);
545			ret = 0;
546			continue;
547		}
548		if (mp->lsn)
549			remove_from_logsync(mp);
550		remove_metapage(page, mp);
551		INCREMENT(mpStat.pagefree);
552		free_metapage(mp);
553	}
554	return ret;
555}
556
557static void metapage_invalidatepage(struct page *page, unsigned int offset,
558				    unsigned int length)
559{
560	BUG_ON(offset || length < PAGE_SIZE);
561
562	BUG_ON(PageWriteback(page));
563
564	metapage_releasepage(page, 0);
565}
566
567const struct address_space_operations jfs_metapage_aops = {
568	.readpage	= metapage_readpage,
569	.writepage	= metapage_writepage,
570	.releasepage	= metapage_releasepage,
571	.invalidatepage	= metapage_invalidatepage,
572	.set_page_dirty	= __set_page_dirty_nobuffers,
573};
574
575struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
576				unsigned int size, int absolute,
577				unsigned long new)
578{
579	int l2BlocksPerPage;
580	int l2bsize;
581	struct address_space *mapping;
582	struct metapage *mp = NULL;
583	struct page *page;
584	unsigned long page_index;
585	unsigned long page_offset;
586
587	jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
588		 inode->i_ino, lblock, absolute);
589
590	l2bsize = inode->i_blkbits;
591	l2BlocksPerPage = PAGE_SHIFT - l2bsize;
592	page_index = lblock >> l2BlocksPerPage;
593	page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
594	if ((page_offset + size) > PAGE_SIZE) {
595		jfs_err("MetaData crosses page boundary!!");
596		jfs_err("lblock = %lx, size  = %d", lblock, size);
597		dump_stack();
598		return NULL;
599	}
600	if (absolute)
601		mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
602	else {
603		/*
604		 * If an nfs client tries to read an inode that is larger
605		 * than any existing inodes, we may try to read past the
606		 * end of the inode map
607		 */
608		if ((lblock << inode->i_blkbits) >= inode->i_size)
609			return NULL;
610		mapping = inode->i_mapping;
611	}
612
613	if (new && (PSIZE == PAGE_SIZE)) {
614		page = grab_cache_page(mapping, page_index);
615		if (!page) {
616			jfs_err("grab_cache_page failed!");
617			return NULL;
618		}
619		SetPageUptodate(page);
620	} else {
621		page = read_mapping_page(mapping, page_index, NULL);
622		if (IS_ERR(page) || !PageUptodate(page)) {
623			jfs_err("read_mapping_page failed!");
624			return NULL;
625		}
626		lock_page(page);
627	}
628
629	mp = page_to_mp(page, page_offset);
630	if (mp) {
631		if (mp->logical_size != size) {
632			jfs_error(inode->i_sb,
633				  "get_mp->logical_size != size\n");
634			jfs_err("logical_size = %d, size = %d",
635				mp->logical_size, size);
636			dump_stack();
637			goto unlock;
638		}
639		mp->count++;
640		lock_metapage(mp);
641		if (test_bit(META_discard, &mp->flag)) {
642			if (!new) {
643				jfs_error(inode->i_sb,
644					  "using a discarded metapage\n");
645				discard_metapage(mp);
646				goto unlock;
647			}
648			clear_bit(META_discard, &mp->flag);
649		}
650	} else {
651		INCREMENT(mpStat.pagealloc);
652		mp = alloc_metapage(GFP_NOFS);
653		if (!mp)
654			goto unlock;
655		mp->page = page;
656		mp->sb = inode->i_sb;
657		mp->flag = 0;
658		mp->xflag = COMMIT_PAGE;
659		mp->count = 1;
660		mp->nohomeok = 0;
661		mp->logical_size = size;
662		mp->data = page_address(page) + page_offset;
663		mp->index = lblock;
664		if (unlikely(insert_metapage(page, mp))) {
665			free_metapage(mp);
666			goto unlock;
667		}
668		lock_metapage(mp);
669	}
670
671	if (new) {
672		jfs_info("zeroing mp = 0x%p", mp);
673		memset(mp->data, 0, PSIZE);
674	}
675
676	unlock_page(page);
677	jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
678	return mp;
679
680unlock:
681	unlock_page(page);
682	return NULL;
683}
684
685void grab_metapage(struct metapage * mp)
686{
687	jfs_info("grab_metapage: mp = 0x%p", mp);
688	get_page(mp->page);
689	lock_page(mp->page);
690	mp->count++;
691	lock_metapage(mp);
692	unlock_page(mp->page);
693}
694
695void force_metapage(struct metapage *mp)
696{
697	struct page *page = mp->page;
698	jfs_info("force_metapage: mp = 0x%p", mp);
699	set_bit(META_forcewrite, &mp->flag);
700	clear_bit(META_sync, &mp->flag);
701	get_page(page);
702	lock_page(page);
703	set_page_dirty(page);
704	if (write_one_page(page))
705		jfs_error(mp->sb, "write_one_page() failed\n");
706	clear_bit(META_forcewrite, &mp->flag);
707	put_page(page);
708}
709
710void hold_metapage(struct metapage *mp)
711{
712	lock_page(mp->page);
713}
714
715void put_metapage(struct metapage *mp)
716{
717	if (mp->count || mp->nohomeok) {
718		/* Someone else will release this */
719		unlock_page(mp->page);
720		return;
721	}
722	get_page(mp->page);
723	mp->count++;
724	lock_metapage(mp);
725	unlock_page(mp->page);
726	release_metapage(mp);
727}
728
729void release_metapage(struct metapage * mp)
730{
731	struct page *page = mp->page;
732	jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
733
734	BUG_ON(!page);
735
736	lock_page(page);
737	unlock_metapage(mp);
738
739	assert(mp->count);
740	if (--mp->count || mp->nohomeok) {
741		unlock_page(page);
742		put_page(page);
743		return;
744	}
745
746	if (test_bit(META_dirty, &mp->flag)) {
747		set_page_dirty(page);
748		if (test_bit(META_sync, &mp->flag)) {
749			clear_bit(META_sync, &mp->flag);
750			if (write_one_page(page))
751				jfs_error(mp->sb, "write_one_page() failed\n");
752			lock_page(page); /* write_one_page unlocks the page */
753		}
754	} else if (mp->lsn)	/* discard_metapage doesn't remove it */
755		remove_from_logsync(mp);
756
757	/* Try to keep metapages from using up too much memory */
758	drop_metapage(page, mp);
759
760	unlock_page(page);
761	put_page(page);
762}
763
764void __invalidate_metapages(struct inode *ip, s64 addr, int len)
765{
766	sector_t lblock;
767	int l2BlocksPerPage = PAGE_SHIFT - ip->i_blkbits;
768	int BlocksPerPage = 1 << l2BlocksPerPage;
769	/* All callers are interested in block device's mapping */
770	struct address_space *mapping =
771		JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
772	struct metapage *mp;
773	struct page *page;
774	unsigned int offset;
775
776	/*
777	 * Mark metapages to discard.  They will eventually be
778	 * released, but should not be written.
779	 */
780	for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
781	     lblock += BlocksPerPage) {
782		page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
783		if (!page)
784			continue;
785		for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
786			mp = page_to_mp(page, offset);
787			if (!mp)
788				continue;
789			if (mp->index < addr)
790				continue;
791			if (mp->index >= addr + len)
792				break;
793
794			clear_bit(META_dirty, &mp->flag);
795			set_bit(META_discard, &mp->flag);
796			if (mp->lsn)
797				remove_from_logsync(mp);
798		}
799		unlock_page(page);
800		put_page(page);
801	}
802}
803
804#ifdef CONFIG_JFS_STATISTICS
805int jfs_mpstat_proc_show(struct seq_file *m, void *v)
806{
807	seq_printf(m,
808		       "JFS Metapage statistics\n"
809		       "=======================\n"
810		       "page allocations = %d\n"
811		       "page frees = %d\n"
812		       "lock waits = %d\n",
813		       mpStat.pagealloc,
814		       mpStat.pagefree,
815		       mpStat.lockwait);
816	return 0;
817}
818#endif