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Linux 2.6.28-rc5
[cris-mirror.git] / fs / jfs / jfs_metapage.c
blobc350057087dd39db3809992338432ac07120bd16
1 /*
2 * Copyright (C) International Business Machines Corp., 2000-2005
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 #include <linux/fs.h>
21 #include <linux/mm.h>
22 #include <linux/module.h>
23 #include <linux/bio.h>
24 #include <linux/init.h>
25 #include <linux/buffer_head.h>
26 #include <linux/mempool.h>
27 #include <linux/seq_file.h>
28 #include "jfs_incore.h"
29 #include "jfs_superblock.h"
30 #include "jfs_filsys.h"
31 #include "jfs_metapage.h"
32 #include "jfs_txnmgr.h"
33 #include "jfs_debug.h"
34
35 #ifdef CONFIG_JFS_STATISTICS
36 static struct {
37 uint pagealloc; /* # of page allocations */
38 uint pagefree; /* # of page frees */
39 uint lockwait; /* # of sleeping lock_metapage() calls */
40 } mpStat;
41 #endif
42
43 #define metapage_locked(mp) test_bit(META_locked, &(mp)->flag)
44 #define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag)
45
46 static inline void unlock_metapage(struct metapage *mp)
47 {
48 clear_bit_unlock(META_locked, &mp->flag);
49 wake_up(&mp->wait);
50 }
51
52 static inline void __lock_metapage(struct metapage *mp)
53 {
54 DECLARE_WAITQUEUE(wait, current);
55 INCREMENT(mpStat.lockwait);
56 add_wait_queue_exclusive(&mp->wait, &wait);
57 do {
58 set_current_state(TASK_UNINTERRUPTIBLE);
59 if (metapage_locked(mp)) {
60 unlock_page(mp->page);
61 io_schedule();
62 lock_page(mp->page);
63 }
64 } while (trylock_metapage(mp));
65 __set_current_state(TASK_RUNNING);
66 remove_wait_queue(&mp->wait, &wait);
67 }
68
69 /*
70 * Must have mp->page locked
71 */
72 static inline void lock_metapage(struct metapage *mp)
73 {
74 if (trylock_metapage(mp))
75 __lock_metapage(mp);
76 }
77
78 #define METAPOOL_MIN_PAGES 32
79 static struct kmem_cache *metapage_cache;
80 static mempool_t *metapage_mempool;
81
82 #define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE)
83
84 #if MPS_PER_PAGE > 1
85
86 struct meta_anchor {
87 int mp_count;
88 atomic_t io_count;
89 struct metapage *mp[MPS_PER_PAGE];
90 };
91 #define mp_anchor(page) ((struct meta_anchor *)page_private(page))
92
93 static inline struct metapage *page_to_mp(struct page *page, int offset)
94 {
95 if (!PagePrivate(page))
96 return NULL;
97 return mp_anchor(page)->mp[offset >> L2PSIZE];
98 }
99
100 static inline int insert_metapage(struct page *page, struct metapage *mp)
101 {
102 struct meta_anchor *a;
103 int index;
104 int l2mp_blocks; /* log2 blocks per metapage */
105
106 if (PagePrivate(page))
107 a = mp_anchor(page);
108 else {
109 a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS);
110 if (!a)
111 return -ENOMEM;
112 set_page_private(page, (unsigned long)a);
113 SetPagePrivate(page);
114 kmap(page);
115 }
116
117 if (mp) {
118 l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
119 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
120 a->mp_count++;
121 a->mp[index] = mp;
122 }
123
124 return 0;
125 }
126
127 static inline void remove_metapage(struct page *page, struct metapage *mp)
128 {
129 struct meta_anchor *a = mp_anchor(page);
130 int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
131 int index;
132
133 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
134
135 BUG_ON(a->mp[index] != mp);
136
137 a->mp[index] = NULL;
138 if (--a->mp_count == 0) {
139 kfree(a);
140 set_page_private(page, 0);
141 ClearPagePrivate(page);
142 kunmap(page);
143 }
144 }
145
146 static inline void inc_io(struct page *page)
147 {
148 atomic_inc(&mp_anchor(page)->io_count);
149 }
150
151 static inline void dec_io(struct page *page, void (*handler) (struct page *))
152 {
153 if (atomic_dec_and_test(&mp_anchor(page)->io_count))
154 handler(page);
155 }
156
157 #else
158 static inline struct metapage *page_to_mp(struct page *page, int offset)
159 {
160 return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL;
161 }
162
163 static inline int insert_metapage(struct page *page, struct metapage *mp)
164 {
165 if (mp) {
166 set_page_private(page, (unsigned long)mp);
167 SetPagePrivate(page);
168 kmap(page);
169 }
170 return 0;
171 }
172
173 static inline void remove_metapage(struct page *page, struct metapage *mp)
174 {
175 set_page_private(page, 0);
176 ClearPagePrivate(page);
177 kunmap(page);
178 }
179
180 #define inc_io(page) do {} while(0)
181 #define dec_io(page, handler) handler(page)
182
183 #endif
184
185 static void init_once(void *foo)
186 {
187 struct metapage *mp = (struct metapage *)foo;
188
189 mp->lid = 0;
190 mp->lsn = 0;
191 mp->flag = 0;
192 mp->data = NULL;
193 mp->clsn = 0;
194 mp->log = NULL;
195 set_bit(META_free, &mp->flag);
196 init_waitqueue_head(&mp->wait);
197 }
198
199 static inline struct metapage *alloc_metapage(gfp_t gfp_mask)
200 {
201 return mempool_alloc(metapage_mempool, gfp_mask);
202 }
203
204 static inline void free_metapage(struct metapage *mp)
205 {
206 mp->flag = 0;
207 set_bit(META_free, &mp->flag);
208
209 mempool_free(mp, metapage_mempool);
210 }
211
212 int __init metapage_init(void)
213 {
214 /*
215 * Allocate the metapage structures
216 */
217 metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage),
218 0, 0, init_once);
219 if (metapage_cache == NULL)
220 return -ENOMEM;
221
222 metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES,
223 metapage_cache);
224
225 if (metapage_mempool == NULL) {
226 kmem_cache_destroy(metapage_cache);
227 return -ENOMEM;
228 }
229
230 return 0;
231 }
232
233 void metapage_exit(void)
234 {
235 mempool_destroy(metapage_mempool);
236 kmem_cache_destroy(metapage_cache);
237 }
238
239 static inline void drop_metapage(struct page *page, struct metapage *mp)
240 {
241 if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) ||
242 test_bit(META_io, &mp->flag))
243 return;
244 remove_metapage(page, mp);
245 INCREMENT(mpStat.pagefree);
246 free_metapage(mp);
247 }
248
249 /*
250 * Metapage address space operations
251 */
252
253 static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
254 int *len)
255 {
256 int rc = 0;
257 int xflag;
258 s64 xaddr;
259 sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
260 inode->i_blkbits;
261
262 if (lblock >= file_blocks)
263 return 0;
264 if (lblock + *len > file_blocks)
265 *len = file_blocks - lblock;
266
267 if (inode->i_ino) {
268 rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0);
269 if ((rc == 0) && *len)
270 lblock = (sector_t)xaddr;
271 else
272 lblock = 0;
273 } /* else no mapping */
274
275 return lblock;
276 }
277
278 static void last_read_complete(struct page *page)
279 {
280 if (!PageError(page))
281 SetPageUptodate(page);
282 unlock_page(page);
283 }
284
285 static void metapage_read_end_io(struct bio *bio, int err)
286 {
287 struct page *page = bio->bi_private;
288
289 if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
290 printk(KERN_ERR "metapage_read_end_io: I/O error\n");
291 SetPageError(page);
292 }
293
294 dec_io(page, last_read_complete);
295 bio_put(bio);
296 }
297
298 static void remove_from_logsync(struct metapage *mp)
299 {
300 struct jfs_log *log = mp->log;
301 unsigned long flags;
302 /*
303 * This can race. Recheck that log hasn't been set to null, and after
304 * acquiring logsync lock, recheck lsn
305 */
306 if (!log)
307 return;
308
309 LOGSYNC_LOCK(log, flags);
310 if (mp->lsn) {
311 mp->log = NULL;
312 mp->lsn = 0;
313 mp->clsn = 0;
314 log->count--;
315 list_del(&mp->synclist);
316 }
317 LOGSYNC_UNLOCK(log, flags);
318 }
319
320 static void last_write_complete(struct page *page)
321 {
322 struct metapage *mp;
323 unsigned int offset;
324
325 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
326 mp = page_to_mp(page, offset);
327 if (mp && test_bit(META_io, &mp->flag)) {
328 if (mp->lsn)
329 remove_from_logsync(mp);
330 clear_bit(META_io, &mp->flag);
331 }
332 /*
333 * I'd like to call drop_metapage here, but I don't think it's
334 * safe unless I have the page locked
335 */
336 }
337 end_page_writeback(page);
338 }
339
340 static void metapage_write_end_io(struct bio *bio, int err)
341 {
342 struct page *page = bio->bi_private;
343
344 BUG_ON(!PagePrivate(page));
345
346 if (! test_bit(BIO_UPTODATE, &bio->bi_flags)) {
347 printk(KERN_ERR "metapage_write_end_io: I/O error\n");
348 SetPageError(page);
349 }
350 dec_io(page, last_write_complete);
351 bio_put(bio);
352 }
353
354 static int metapage_writepage(struct page *page, struct writeback_control *wbc)
355 {
356 struct bio *bio = NULL;
357 int block_offset; /* block offset of mp within page */
358 struct inode *inode = page->mapping->host;
359 int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
360 int len;
361 int xlen;
362 struct metapage *mp;
363 int redirty = 0;
364 sector_t lblock;
365 int nr_underway = 0;
366 sector_t pblock;
367 sector_t next_block = 0;
368 sector_t page_start;
369 unsigned long bio_bytes = 0;
370 unsigned long bio_offset = 0;
371 int offset;
372
373 page_start = (sector_t)page->index <<
374 (PAGE_CACHE_SHIFT - inode->i_blkbits);
375 BUG_ON(!PageLocked(page));
376 BUG_ON(PageWriteback(page));
377 set_page_writeback(page);
378
379 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
380 mp = page_to_mp(page, offset);
381
382 if (!mp || !test_bit(META_dirty, &mp->flag))
383 continue;
384
385 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) {
386 redirty = 1;
387 /*
388 * Make sure this page isn't blocked indefinitely.
389 * If the journal isn't undergoing I/O, push it
390 */
391 if (mp->log && !(mp->log->cflag & logGC_PAGEOUT))
392 jfs_flush_journal(mp->log, 0);
393 continue;
394 }
395
396 clear_bit(META_dirty, &mp->flag);
397 block_offset = offset >> inode->i_blkbits;
398 lblock = page_start + block_offset;
399 if (bio) {
400 if (xlen && lblock == next_block) {
401 /* Contiguous, in memory & on disk */
402 len = min(xlen, blocks_per_mp);
403 xlen -= len;
404 bio_bytes += len << inode->i_blkbits;
405 set_bit(META_io, &mp->flag);
406 continue;
407 }
408 /* Not contiguous */
409 if (bio_add_page(bio, page, bio_bytes, bio_offset) <
410 bio_bytes)
411 goto add_failed;
412 /*
413 * Increment counter before submitting i/o to keep
414 * count from hitting zero before we're through
415 */
416 inc_io(page);
417 if (!bio->bi_size)
418 goto dump_bio;
419 submit_bio(WRITE, bio);
420 nr_underway++;
421 bio = NULL;
422 } else
423 inc_io(page);
424 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
425 pblock = metapage_get_blocks(inode, lblock, &xlen);
426 if (!pblock) {
427 /* Need better error handling */
428 printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
429 dec_io(page, last_write_complete);
430 continue;
431 }
432 set_bit(META_io, &mp->flag);
433 len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage);
434
435 bio = bio_alloc(GFP_NOFS, 1);
436 bio->bi_bdev = inode->i_sb->s_bdev;
437 bio->bi_sector = pblock << (inode->i_blkbits - 9);
438 bio->bi_end_io = metapage_write_end_io;
439 bio->bi_private = page;
440
441 /* Don't call bio_add_page yet, we may add to this vec */
442 bio_offset = offset;
443 bio_bytes = len << inode->i_blkbits;
444
445 xlen -= len;
446 next_block = lblock + len;
447 }
448 if (bio) {
449 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
450 goto add_failed;
451 if (!bio->bi_size)
452 goto dump_bio;
453
454 submit_bio(WRITE, bio);
455 nr_underway++;
456 }
457 if (redirty)
458 redirty_page_for_writepage(wbc, page);
459
460 unlock_page(page);
461
462 if (nr_underway == 0)
463 end_page_writeback(page);
464
465 return 0;
466 add_failed:
467 /* We should never reach here, since we're only adding one vec */
468 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
469 goto skip;
470 dump_bio:
471 print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16,
472 4, bio, sizeof(*bio), 0);
473 skip:
474 bio_put(bio);
475 unlock_page(page);
476 dec_io(page, last_write_complete);
477
478 return -EIO;
479 }
480
481 static int metapage_readpage(struct file *fp, struct page *page)
482 {
483 struct inode *inode = page->mapping->host;
484 struct bio *bio = NULL;
485 int block_offset;
486 int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits;
487 sector_t page_start; /* address of page in fs blocks */
488 sector_t pblock;
489 int xlen;
490 unsigned int len;
491 int offset;
492
493 BUG_ON(!PageLocked(page));
494 page_start = (sector_t)page->index <<
495 (PAGE_CACHE_SHIFT - inode->i_blkbits);
496
497 block_offset = 0;
498 while (block_offset < blocks_per_page) {
499 xlen = blocks_per_page - block_offset;
500 pblock = metapage_get_blocks(inode, page_start + block_offset,
501 &xlen);
502 if (pblock) {
503 if (!PagePrivate(page))
504 insert_metapage(page, NULL);
505 inc_io(page);
506 if (bio)
507 submit_bio(READ, bio);
508
509 bio = bio_alloc(GFP_NOFS, 1);
510 bio->bi_bdev = inode->i_sb->s_bdev;
511 bio->bi_sector = pblock << (inode->i_blkbits - 9);
512 bio->bi_end_io = metapage_read_end_io;
513 bio->bi_private = page;
514 len = xlen << inode->i_blkbits;
515 offset = block_offset << inode->i_blkbits;
516 if (bio_add_page(bio, page, len, offset) < len)
517 goto add_failed;
518 block_offset += xlen;
519 } else
520 block_offset++;
521 }
522 if (bio)
523 submit_bio(READ, bio);
524 else
525 unlock_page(page);
526
527 return 0;
528
529 add_failed:
530 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
531 bio_put(bio);
532 dec_io(page, last_read_complete);
533 return -EIO;
534 }
535
536 static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
537 {
538 struct metapage *mp;
539 int ret = 1;
540 int offset;
541
542 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
543 mp = page_to_mp(page, offset);
544
545 if (!mp)
546 continue;
547
548 jfs_info("metapage_releasepage: mp = 0x%p", mp);
549 if (mp->count || mp->nohomeok ||
550 test_bit(META_dirty, &mp->flag)) {
551 jfs_info("count = %ld, nohomeok = %d", mp->count,
552 mp->nohomeok);
553 ret = 0;
554 continue;
555 }
556 if (mp->lsn)
557 remove_from_logsync(mp);
558 remove_metapage(page, mp);
559 INCREMENT(mpStat.pagefree);
560 free_metapage(mp);
561 }
562 return ret;
563 }
564
565 static void metapage_invalidatepage(struct page *page, unsigned long offset)
566 {
567 BUG_ON(offset);
568
569 BUG_ON(PageWriteback(page));
570
571 metapage_releasepage(page, 0);
572 }
573
574 const struct address_space_operations jfs_metapage_aops = {
575 .readpage = metapage_readpage,
576 .writepage = metapage_writepage,
577 .sync_page = block_sync_page,
578 .releasepage = metapage_releasepage,
579 .invalidatepage = metapage_invalidatepage,
580 .set_page_dirty = __set_page_dirty_nobuffers,
581 };
582
583 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
584 unsigned int size, int absolute,
585 unsigned long new)
586 {
587 int l2BlocksPerPage;
588 int l2bsize;
589 struct address_space *mapping;
590 struct metapage *mp = NULL;
591 struct page *page;
592 unsigned long page_index;
593 unsigned long page_offset;
594
595 jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
596 inode->i_ino, lblock, absolute);
597
598 l2bsize = inode->i_blkbits;
599 l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
600 page_index = lblock >> l2BlocksPerPage;
601 page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
602 if ((page_offset + size) > PAGE_CACHE_SIZE) {
603 jfs_err("MetaData crosses page boundary!!");
604 jfs_err("lblock = %lx, size = %d", lblock, size);
605 dump_stack();
606 return NULL;
607 }
608 if (absolute)
609 mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
610 else {
611 /*
612 * If an nfs client tries to read an inode that is larger
613 * than any existing inodes, we may try to read past the
614 * end of the inode map
615 */
616 if ((lblock << inode->i_blkbits) >= inode->i_size)
617 return NULL;
618 mapping = inode->i_mapping;
619 }
620
621 if (new && (PSIZE == PAGE_CACHE_SIZE)) {
622 page = grab_cache_page(mapping, page_index);
623 if (!page) {
624 jfs_err("grab_cache_page failed!");
625 return NULL;
626 }
627 SetPageUptodate(page);
628 } else {
629 page = read_mapping_page(mapping, page_index, NULL);
630 if (IS_ERR(page) || !PageUptodate(page)) {
631 jfs_err("read_mapping_page failed!");
632 return NULL;
633 }
634 lock_page(page);
635 }
636
637 mp = page_to_mp(page, page_offset);
638 if (mp) {
639 if (mp->logical_size != size) {
640 jfs_error(inode->i_sb,
641 "__get_metapage: mp->logical_size != size");
642 jfs_err("logical_size = %d, size = %d",
643 mp->logical_size, size);
644 dump_stack();
645 goto unlock;
646 }
647 mp->count++;
648 lock_metapage(mp);
649 if (test_bit(META_discard, &mp->flag)) {
650 if (!new) {
651 jfs_error(inode->i_sb,
652 "__get_metapage: using a "
653 "discarded metapage");
654 discard_metapage(mp);
655 goto unlock;
656 }
657 clear_bit(META_discard, &mp->flag);
658 }
659 } else {
660 INCREMENT(mpStat.pagealloc);
661 mp = alloc_metapage(GFP_NOFS);
662 mp->page = page;
663 mp->flag = 0;
664 mp->xflag = COMMIT_PAGE;
665 mp->count = 1;
666 mp->nohomeok = 0;
667 mp->logical_size = size;
668 mp->data = page_address(page) + page_offset;
669 mp->index = lblock;
670 if (unlikely(insert_metapage(page, mp))) {
671 free_metapage(mp);
672 goto unlock;
673 }
674 lock_metapage(mp);
675 }
676
677 if (new) {
678 jfs_info("zeroing mp = 0x%p", mp);
679 memset(mp->data, 0, PSIZE);
680 }
681
682 unlock_page(page);
683 jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
684 return mp;
685
686 unlock:
687 unlock_page(page);
688 return NULL;
689 }
690
691 void grab_metapage(struct metapage * mp)
692 {
693 jfs_info("grab_metapage: mp = 0x%p", mp);
694 page_cache_get(mp->page);
695 lock_page(mp->page);
696 mp->count++;
697 lock_metapage(mp);
698 unlock_page(mp->page);
699 }
700
701 void force_metapage(struct metapage *mp)
702 {
703 struct page *page = mp->page;
704 jfs_info("force_metapage: mp = 0x%p", mp);
705 set_bit(META_forcewrite, &mp->flag);
706 clear_bit(META_sync, &mp->flag);
707 page_cache_get(page);
708 lock_page(page);
709 set_page_dirty(page);
710 write_one_page(page, 1);
711 clear_bit(META_forcewrite, &mp->flag);
712 page_cache_release(page);
713 }
714
715 void hold_metapage(struct metapage *mp)
716 {
717 lock_page(mp->page);
718 }
719
720 void put_metapage(struct metapage *mp)
721 {
722 if (mp->count || mp->nohomeok) {
723 /* Someone else will release this */
724 unlock_page(mp->page);
725 return;
726 }
727 page_cache_get(mp->page);
728 mp->count++;
729 lock_metapage(mp);
730 unlock_page(mp->page);
731 release_metapage(mp);
732 }
733
734 void release_metapage(struct metapage * mp)
735 {
736 struct page *page = mp->page;
737 jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
738
739 BUG_ON(!page);
740
741 lock_page(page);
742 unlock_metapage(mp);
743
744 assert(mp->count);
745 if (--mp->count || mp->nohomeok) {
746 unlock_page(page);
747 page_cache_release(page);
748 return;
749 }
750
751 if (test_bit(META_dirty, &mp->flag)) {
752 set_page_dirty(page);
753 if (test_bit(META_sync, &mp->flag)) {
754 clear_bit(META_sync, &mp->flag);
755 write_one_page(page, 1);
756 lock_page(page); /* write_one_page unlocks the page */
757 }
758 } else if (mp->lsn) /* discard_metapage doesn't remove it */
759 remove_from_logsync(mp);
760
761 /* Try to keep metapages from using up too much memory */
762 drop_metapage(page, mp);
763
764 unlock_page(page);
765 page_cache_release(page);
766 }
767
768 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
769 {
770 sector_t lblock;
771 int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
772 int BlocksPerPage = 1 << l2BlocksPerPage;
773 /* All callers are interested in block device's mapping */
774 struct address_space *mapping =
775 JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
776 struct metapage *mp;
777 struct page *page;
778 unsigned int offset;
779
780 /*
781 * Mark metapages to discard. They will eventually be
782 * released, but should not be written.
783 */
784 for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
785 lblock += BlocksPerPage) {
786 page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
787 if (!page)
788 continue;
789 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
790 mp = page_to_mp(page, offset);
791 if (!mp)
792 continue;
793 if (mp->index < addr)
794 continue;
795 if (mp->index >= addr + len)
796 break;
797
798 clear_bit(META_dirty, &mp->flag);
799 set_bit(META_discard, &mp->flag);
800 if (mp->lsn)
801 remove_from_logsync(mp);
802 }
803 unlock_page(page);
804 page_cache_release(page);
805 }
806 }
807
808 #ifdef CONFIG_JFS_STATISTICS
809 static int jfs_mpstat_proc_show(struct seq_file *m, void *v)
810 {
811 seq_printf(m,
812 "JFS Metapage statistics\n"
813 "=======================\n"
814 "page allocations = %d\n"
815 "page frees = %d\n"
816 "lock waits = %d\n",
817 mpStat.pagealloc,
818 mpStat.pagefree,
819 mpStat.lockwait);
820 return 0;
821 }
822
823 static int jfs_mpstat_proc_open(struct inode *inode, struct file *file)
824 {
825 return single_open(file, jfs_mpstat_proc_show, NULL);
826 }
827
828 const struct file_operations jfs_mpstat_proc_fops = {
829 .owner = THIS_MODULE,
830 .open = jfs_mpstat_proc_open,
831 .read = seq_read,
832 .llseek = seq_lseek,
833 .release = single_release,
834 };
835 #endif
CRIS linux kernel tree