?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / fs / jfs / jfs_metapage.c
blobd1e64f2f2fcd1b434b4c07434bb19b82e6b189f9
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/bio.h>
23 #include <linux/init.h>
24 #include <linux/buffer_head.h>
25 #include <linux/mempool.h>
26 #include "jfs_incore.h"
27 #include "jfs_superblock.h"
28 #include "jfs_filsys.h"
29 #include "jfs_metapage.h"
30 #include "jfs_txnmgr.h"
31 #include "jfs_debug.h"
32
33 #ifdef CONFIG_JFS_STATISTICS
34 static struct {
35 uint pagealloc; /* # of page allocations */
36 uint pagefree; /* # of page frees */
37 uint lockwait; /* # of sleeping lock_metapage() calls */
38 } mpStat;
39 #endif
40
41 #define metapage_locked(mp) test_bit(META_locked, &(mp)->flag)
42 #define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag)
43
44 static inline void unlock_metapage(struct metapage *mp)
45 {
46 clear_bit_unlock(META_locked, &mp->flag);
47 wake_up(&mp->wait);
48 }
49
50 static inline void __lock_metapage(struct metapage *mp)
51 {
52 DECLARE_WAITQUEUE(wait, current);
53 INCREMENT(mpStat.lockwait);
54 add_wait_queue_exclusive(&mp->wait, &wait);
55 do {
56 set_current_state(TASK_UNINTERRUPTIBLE);
57 if (metapage_locked(mp)) {
58 unlock_page(mp->page);
59 io_schedule();
60 lock_page(mp->page);
61 }
62 } while (trylock_metapage(mp));
63 __set_current_state(TASK_RUNNING);
64 remove_wait_queue(&mp->wait, &wait);
65 }
66
67 /*
68 * Must have mp->page locked
69 */
70 static inline void lock_metapage(struct metapage *mp)
71 {
72 if (trylock_metapage(mp))
73 __lock_metapage(mp);
74 }
75
76 #define METAPOOL_MIN_PAGES 32
77 static struct kmem_cache *metapage_cache;
78 static mempool_t *metapage_mempool;
79
80 #define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE)
81
82 #if MPS_PER_PAGE > 1
83
84 struct meta_anchor {
85 int mp_count;
86 atomic_t io_count;
87 struct metapage *mp[MPS_PER_PAGE];
88 };
89 #define mp_anchor(page) ((struct meta_anchor *)page_private(page))
90
91 static inline struct metapage *page_to_mp(struct page *page, int offset)
92 {
93 if (!PagePrivate(page))
94 return NULL;
95 return mp_anchor(page)->mp[offset >> L2PSIZE];
96 }
97
98 static inline int insert_metapage(struct page *page, struct metapage *mp)
99 {
100 struct meta_anchor *a;
101 int index;
102 int l2mp_blocks; /* log2 blocks per metapage */
103
104 if (PagePrivate(page))
105 a = mp_anchor(page);
106 else {
107 a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS);
108 if (!a)
109 return -ENOMEM;
110 set_page_private(page, (unsigned long)a);
111 SetPagePrivate(page);
112 kmap(page);
113 }
114
115 if (mp) {
116 l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
117 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
118 a->mp_count++;
119 a->mp[index] = mp;
120 }
121
122 return 0;
123 }
124
125 static inline void remove_metapage(struct page *page, struct metapage *mp)
126 {
127 struct meta_anchor *a = mp_anchor(page);
128 int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
129 int index;
130
131 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
132
133 BUG_ON(a->mp[index] != mp);
134
135 a->mp[index] = NULL;
136 if (--a->mp_count == 0) {
137 kfree(a);
138 set_page_private(page, 0);
139 ClearPagePrivate(page);
140 kunmap(page);
141 }
142 }
143
144 static inline void inc_io(struct page *page)
145 {
146 atomic_inc(&mp_anchor(page)->io_count);
147 }
148
149 static inline void dec_io(struct page *page, void (*handler) (struct page *))
150 {
151 if (atomic_dec_and_test(&mp_anchor(page)->io_count))
152 handler(page);
153 }
154
155 #else
156 static inline struct metapage *page_to_mp(struct page *page, int offset)
157 {
158 return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL;
159 }
160
161 static inline int insert_metapage(struct page *page, struct metapage *mp)
162 {
163 if (mp) {
164 set_page_private(page, (unsigned long)mp);
165 SetPagePrivate(page);
166 kmap(page);
167 }
168 return 0;
169 }
170
171 static inline void remove_metapage(struct page *page, struct metapage *mp)
172 {
173 set_page_private(page, 0);
174 ClearPagePrivate(page);
175 kunmap(page);
176 }
177
178 #define inc_io(page) do {} while(0)
179 #define dec_io(page, handler) handler(page)
180
181 #endif
182
183 static void init_once(struct kmem_cache *cachep, void *foo)
184 {
185 struct metapage *mp = (struct metapage *)foo;
186
187 mp->lid = 0;
188 mp->lsn = 0;
189 mp->flag = 0;
190 mp->data = NULL;
191 mp->clsn = 0;
192 mp->log = NULL;
193 set_bit(META_free, &mp->flag);
194 init_waitqueue_head(&mp->wait);
195 }
196
197 static inline struct metapage *alloc_metapage(gfp_t gfp_mask)
198 {
199 return mempool_alloc(metapage_mempool, gfp_mask);
200 }
201
202 static inline void free_metapage(struct metapage *mp)
203 {
204 mp->flag = 0;
205 set_bit(META_free, &mp->flag);
206
207 mempool_free(mp, metapage_mempool);
208 }
209
210 int __init metapage_init(void)
211 {
212 /*
213 * Allocate the metapage structures
214 */
215 metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage),
216 0, 0, init_once);
217 if (metapage_cache == NULL)
218 return -ENOMEM;
219
220 metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES,
221 metapage_cache);
222
223 if (metapage_mempool == NULL) {
224 kmem_cache_destroy(metapage_cache);
225 return -ENOMEM;
226 }
227
228 return 0;
229 }
230
231 void metapage_exit(void)
232 {
233 mempool_destroy(metapage_mempool);
234 kmem_cache_destroy(metapage_cache);
235 }
236
237 static inline void drop_metapage(struct page *page, struct metapage *mp)
238 {
239 if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) ||
240 test_bit(META_io, &mp->flag))
241 return;
242 remove_metapage(page, mp);
243 INCREMENT(mpStat.pagefree);
244 free_metapage(mp);
245 }
246
247 /*
248 * Metapage address space operations
249 */
250
251 static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
252 int *len)
253 {
254 int rc = 0;
255 int xflag;
256 s64 xaddr;
257 sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
258 inode->i_blkbits;
259
260 if (lblock >= file_blocks)
261 return 0;
262 if (lblock + *len > file_blocks)
263 *len = file_blocks - lblock;
264
265 if (inode->i_ino) {
266 rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0);
267 if ((rc == 0) && *len)
268 lblock = (sector_t)xaddr;
269 else
270 lblock = 0;
271 } /* else no mapping */
272
273 return lblock;
274 }
275
276 static void last_read_complete(struct page *page)
277 {
278 if (!PageError(page))
279 SetPageUptodate(page);
280 unlock_page(page);
281 }
282
283 static void metapage_read_end_io(struct bio *bio, int err)
284 {
285 struct page *page = bio->bi_private;
286
287 if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
288 printk(KERN_ERR "metapage_read_end_io: I/O error\n");
289 SetPageError(page);
290 }
291
292 dec_io(page, last_read_complete);
293 bio_put(bio);
294 }
295
296 static void remove_from_logsync(struct metapage *mp)
297 {
298 struct jfs_log *log = mp->log;
299 unsigned long flags;
300 /*
301 * This can race. Recheck that log hasn't been set to null, and after
302 * acquiring logsync lock, recheck lsn
303 */
304 if (!log)
305 return;
306
307 LOGSYNC_LOCK(log, flags);
308 if (mp->lsn) {
309 mp->log = NULL;
310 mp->lsn = 0;
311 mp->clsn = 0;
312 log->count--;
313 list_del(&mp->synclist);
314 }
315 LOGSYNC_UNLOCK(log, flags);
316 }
317
318 static void last_write_complete(struct page *page)
319 {
320 struct metapage *mp;
321 unsigned int offset;
322
323 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
324 mp = page_to_mp(page, offset);
325 if (mp && test_bit(META_io, &mp->flag)) {
326 if (mp->lsn)
327 remove_from_logsync(mp);
328 clear_bit(META_io, &mp->flag);
329 }
330 /*
331 * I'd like to call drop_metapage here, but I don't think it's
332 * safe unless I have the page locked
333 */
334 }
335 end_page_writeback(page);
336 }
337
338 static void metapage_write_end_io(struct bio *bio, int err)
339 {
340 struct page *page = bio->bi_private;
341
342 BUG_ON(!PagePrivate(page));
343
344 if (! test_bit(BIO_UPTODATE, &bio->bi_flags)) {
345 printk(KERN_ERR "metapage_write_end_io: I/O error\n");
346 SetPageError(page);
347 }
348 dec_io(page, last_write_complete);
349 bio_put(bio);
350 }
351
352 static int metapage_writepage(struct page *page, struct writeback_control *wbc)
353 {
354 struct bio *bio = NULL;
355 int block_offset; /* block offset of mp within page */
356 struct inode *inode = page->mapping->host;
357 int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
358 int len;
359 int xlen;
360 struct metapage *mp;
361 int redirty = 0;
362 sector_t lblock;
363 int nr_underway = 0;
364 sector_t pblock;
365 sector_t next_block = 0;
366 sector_t page_start;
367 unsigned long bio_bytes = 0;
368 unsigned long bio_offset = 0;
369 int offset;
370
371 page_start = (sector_t)page->index <<
372 (PAGE_CACHE_SHIFT - inode->i_blkbits);
373 BUG_ON(!PageLocked(page));
374 BUG_ON(PageWriteback(page));
375 set_page_writeback(page);
376
377 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
378 mp = page_to_mp(page, offset);
379
380 if (!mp || !test_bit(META_dirty, &mp->flag))
381 continue;
382
383 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) {
384 redirty = 1;
385 /*
386 * Make sure this page isn't blocked indefinitely.
387 * If the journal isn't undergoing I/O, push it
388 */
389 if (mp->log && !(mp->log->cflag & logGC_PAGEOUT))
390 jfs_flush_journal(mp->log, 0);
391 continue;
392 }
393
394 clear_bit(META_dirty, &mp->flag);
395 block_offset = offset >> inode->i_blkbits;
396 lblock = page_start + block_offset;
397 if (bio) {
398 if (xlen && lblock == next_block) {
399 /* Contiguous, in memory & on disk */
400 len = min(xlen, blocks_per_mp);
401 xlen -= len;
402 bio_bytes += len << inode->i_blkbits;
403 set_bit(META_io, &mp->flag);
404 continue;
405 }
406 /* Not contiguous */
407 if (bio_add_page(bio, page, bio_bytes, bio_offset) <
408 bio_bytes)
409 goto add_failed;
410 /*
411 * Increment counter before submitting i/o to keep
412 * count from hitting zero before we're through
413 */
414 inc_io(page);
415 if (!bio->bi_size)
416 goto dump_bio;
417 submit_bio(WRITE, bio);
418 nr_underway++;
419 bio = NULL;
420 } else
421 inc_io(page);
422 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
423 pblock = metapage_get_blocks(inode, lblock, &xlen);
424 if (!pblock) {
425 /* Need better error handling */
426 printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
427 dec_io(page, last_write_complete);
428 continue;
429 }
430 set_bit(META_io, &mp->flag);
431 len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage);
432
433 bio = bio_alloc(GFP_NOFS, 1);
434 bio->bi_bdev = inode->i_sb->s_bdev;
435 bio->bi_sector = pblock << (inode->i_blkbits - 9);
436 bio->bi_end_io = metapage_write_end_io;
437 bio->bi_private = page;
438
439 /* Don't call bio_add_page yet, we may add to this vec */
440 bio_offset = offset;
441 bio_bytes = len << inode->i_blkbits;
442
443 xlen -= len;
444 next_block = lblock + len;
445 }
446 if (bio) {
447 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
448 goto add_failed;
449 if (!bio->bi_size)
450 goto dump_bio;
451
452 submit_bio(WRITE, bio);
453 nr_underway++;
454 }
455 if (redirty)
456 redirty_page_for_writepage(wbc, page);
457
458 unlock_page(page);
459
460 if (nr_underway == 0)
461 end_page_writeback(page);
462
463 return 0;
464 add_failed:
465 /* We should never reach here, since we're only adding one vec */
466 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
467 goto skip;
468 dump_bio:
469 print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16,
470 4, bio, sizeof(*bio), 0);
471 skip:
472 bio_put(bio);
473 unlock_page(page);
474 dec_io(page, last_write_complete);
475
476 return -EIO;
477 }
478
479 static int metapage_readpage(struct file *fp, struct page *page)
480 {
481 struct inode *inode = page->mapping->host;
482 struct bio *bio = NULL;
483 int block_offset;
484 int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits;
485 sector_t page_start; /* address of page in fs blocks */
486 sector_t pblock;
487 int xlen;
488 unsigned int len;
489 int offset;
490
491 BUG_ON(!PageLocked(page));
492 page_start = (sector_t)page->index <<
493 (PAGE_CACHE_SHIFT - inode->i_blkbits);
494
495 block_offset = 0;
496 while (block_offset < blocks_per_page) {
497 xlen = blocks_per_page - block_offset;
498 pblock = metapage_get_blocks(inode, page_start + block_offset,
499 &xlen);
500 if (pblock) {
501 if (!PagePrivate(page))
502 insert_metapage(page, NULL);
503 inc_io(page);
504 if (bio)
505 submit_bio(READ, bio);
506
507 bio = bio_alloc(GFP_NOFS, 1);
508 bio->bi_bdev = inode->i_sb->s_bdev;
509 bio->bi_sector = pblock << (inode->i_blkbits - 9);
510 bio->bi_end_io = metapage_read_end_io;
511 bio->bi_private = page;
512 len = xlen << inode->i_blkbits;
513 offset = block_offset << inode->i_blkbits;
514 if (bio_add_page(bio, page, len, offset) < len)
515 goto add_failed;
516 block_offset += xlen;
517 } else
518 block_offset++;
519 }
520 if (bio)
521 submit_bio(READ, bio);
522 else
523 unlock_page(page);
524
525 return 0;
526
527 add_failed:
528 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
529 bio_put(bio);
530 dec_io(page, last_read_complete);
531 return -EIO;
532 }
533
534 static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
535 {
536 struct metapage *mp;
537 int ret = 1;
538 int offset;
539
540 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
541 mp = page_to_mp(page, offset);
542
543 if (!mp)
544 continue;
545
546 jfs_info("metapage_releasepage: mp = 0x%p", mp);
547 if (mp->count || mp->nohomeok ||
548 test_bit(META_dirty, &mp->flag)) {
549 jfs_info("count = %ld, nohomeok = %d", mp->count,
550 mp->nohomeok);
551 ret = 0;
552 continue;
553 }
554 if (mp->lsn)
555 remove_from_logsync(mp);
556 remove_metapage(page, mp);
557 INCREMENT(mpStat.pagefree);
558 free_metapage(mp);
559 }
560 return ret;
561 }
562
563 static void metapage_invalidatepage(struct page *page, unsigned long offset)
564 {
565 BUG_ON(offset);
566
567 BUG_ON(PageWriteback(page));
568
569 metapage_releasepage(page, 0);
570 }
571
572 const struct address_space_operations jfs_metapage_aops = {
573 .readpage = metapage_readpage,
574 .writepage = metapage_writepage,
575 .sync_page = block_sync_page,
576 .releasepage = metapage_releasepage,
577 .invalidatepage = metapage_invalidatepage,
578 .set_page_dirty = __set_page_dirty_nobuffers,
579 };
580
581 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
582 unsigned int size, int absolute,
583 unsigned long new)
584 {
585 int l2BlocksPerPage;
586 int l2bsize;
587 struct address_space *mapping;
588 struct metapage *mp = NULL;
589 struct page *page;
590 unsigned long page_index;
591 unsigned long page_offset;
592
593 jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
594 inode->i_ino, lblock, absolute);
595
596 l2bsize = inode->i_blkbits;
597 l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
598 page_index = lblock >> l2BlocksPerPage;
599 page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
600 if ((page_offset + size) > PAGE_CACHE_SIZE) {
601 jfs_err("MetaData crosses page boundary!!");
602 jfs_err("lblock = %lx, size = %d", lblock, size);
603 dump_stack();
604 return NULL;
605 }
606 if (absolute)
607 mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
608 else {
609 /*
610 * If an nfs client tries to read an inode that is larger
611 * than any existing inodes, we may try to read past the
612 * end of the inode map
613 */
614 if ((lblock << inode->i_blkbits) >= inode->i_size)
615 return NULL;
616 mapping = inode->i_mapping;
617 }
618
619 if (new && (PSIZE == PAGE_CACHE_SIZE)) {
620 page = grab_cache_page(mapping, page_index);
621 if (!page) {
622 jfs_err("grab_cache_page failed!");
623 return NULL;
624 }
625 SetPageUptodate(page);
626 } else {
627 page = read_mapping_page(mapping, page_index, NULL);
628 if (IS_ERR(page) || !PageUptodate(page)) {
629 jfs_err("read_mapping_page failed!");
630 return NULL;
631 }
632 lock_page(page);
633 }
634
635 mp = page_to_mp(page, page_offset);
636 if (mp) {
637 if (mp->logical_size != size) {
638 jfs_error(inode->i_sb,
639 "__get_metapage: mp->logical_size != size");
640 jfs_err("logical_size = %d, size = %d",
641 mp->logical_size, size);
642 dump_stack();
643 goto unlock;
644 }
645 mp->count++;
646 lock_metapage(mp);
647 if (test_bit(META_discard, &mp->flag)) {
648 if (!new) {
649 jfs_error(inode->i_sb,
650 "__get_metapage: using a "
651 "discarded metapage");
652 discard_metapage(mp);
653 goto unlock;
654 }
655 clear_bit(META_discard, &mp->flag);
656 }
657 } else {
658 INCREMENT(mpStat.pagealloc);
659 mp = alloc_metapage(GFP_NOFS);
660 mp->page = page;
661 mp->flag = 0;
662 mp->xflag = COMMIT_PAGE;
663 mp->count = 1;
664 mp->nohomeok = 0;
665 mp->logical_size = size;
666 mp->data = page_address(page) + page_offset;
667 mp->index = lblock;
668 if (unlikely(insert_metapage(page, mp))) {
669 free_metapage(mp);
670 goto unlock;
671 }
672 lock_metapage(mp);
673 }
674
675 if (new) {
676 jfs_info("zeroing mp = 0x%p", mp);
677 memset(mp->data, 0, PSIZE);
678 }
679
680 unlock_page(page);
681 jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
682 return mp;
683
684 unlock:
685 unlock_page(page);
686 return NULL;
687 }
688
689 void grab_metapage(struct metapage * mp)
690 {
691 jfs_info("grab_metapage: mp = 0x%p", mp);
692 page_cache_get(mp->page);
693 lock_page(mp->page);
694 mp->count++;
695 lock_metapage(mp);
696 unlock_page(mp->page);
697 }
698
699 void force_metapage(struct metapage *mp)
700 {
701 struct page *page = mp->page;
702 jfs_info("force_metapage: mp = 0x%p", mp);
703 set_bit(META_forcewrite, &mp->flag);
704 clear_bit(META_sync, &mp->flag);
705 page_cache_get(page);
706 lock_page(page);
707 set_page_dirty(page);
708 write_one_page(page, 1);
709 clear_bit(META_forcewrite, &mp->flag);
710 page_cache_release(page);
711 }
712
713 void hold_metapage(struct metapage *mp)
714 {
715 lock_page(mp->page);
716 }
717
718 void put_metapage(struct metapage *mp)
719 {
720 if (mp->count || mp->nohomeok) {
721 /* Someone else will release this */
722 unlock_page(mp->page);
723 return;
724 }
725 page_cache_get(mp->page);
726 mp->count++;
727 lock_metapage(mp);
728 unlock_page(mp->page);
729 release_metapage(mp);
730 }
731
732 void release_metapage(struct metapage * mp)
733 {
734 struct page *page = mp->page;
735 jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
736
737 BUG_ON(!page);
738
739 lock_page(page);
740 unlock_metapage(mp);
741
742 assert(mp->count);
743 if (--mp->count || mp->nohomeok) {
744 unlock_page(page);
745 page_cache_release(page);
746 return;
747 }
748
749 if (test_bit(META_dirty, &mp->flag)) {
750 set_page_dirty(page);
751 if (test_bit(META_sync, &mp->flag)) {
752 clear_bit(META_sync, &mp->flag);
753 write_one_page(page, 1);
754 lock_page(page); /* write_one_page unlocks the page */
755 }
756 } else if (mp->lsn) /* discard_metapage doesn't remove it */
757 remove_from_logsync(mp);
758
759 /* Try to keep metapages from using up too much memory */
760 drop_metapage(page, mp);
761
762 unlock_page(page);
763 page_cache_release(page);
764 }
765
766 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
767 {
768 sector_t lblock;
769 int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
770 int BlocksPerPage = 1 << l2BlocksPerPage;
771 /* All callers are interested in block device's mapping */
772 struct address_space *mapping =
773 JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
774 struct metapage *mp;
775 struct page *page;
776 unsigned int offset;
777
778 /*
779 * Mark metapages to discard. They will eventually be
780 * released, but should not be written.
781 */
782 for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
783 lblock += BlocksPerPage) {
784 page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
785 if (!page)
786 continue;
787 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
788 mp = page_to_mp(page, offset);
789 if (!mp)
790 continue;
791 if (mp->index < addr)
792 continue;
793 if (mp->index >= addr + len)
794 break;
795
796 clear_bit(META_dirty, &mp->flag);
797 set_bit(META_discard, &mp->flag);
798 if (mp->lsn)
799 remove_from_logsync(mp);
800 }
801 unlock_page(page);
802 page_cache_release(page);
803 }
804 }
805
806 #ifdef CONFIG_JFS_STATISTICS
807 int jfs_mpstat_read(char *buffer, char **start, off_t offset, int length,
808 int *eof, void *data)
809 {
810 int len = 0;
811 off_t begin;
812
813 len += sprintf(buffer,
814 "JFS Metapage statistics\n"
815 "=======================\n"
816 "page allocations = %d\n"
817 "page frees = %d\n"
818 "lock waits = %d\n",
819 mpStat.pagealloc,
820 mpStat.pagefree,
821 mpStat.lockwait);
822
823 begin = offset;
824 *start = buffer + begin;
825 len -= begin;
826
827 if (len > length)
828 len = length;
829 else
830 *eof = 1;
831
832 if (len < 0)
833 len = 0;
834
835 return len;
836 }
837 #endif
mah project overlay