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[PATCH] briq_panel: read() and write() get __user pointers, damnit
[linux-2.6/verdex.git] / fs / jfs / jfs_metapage.c
blobe1e0a6e6ebdfb8d0e1c591a124a249e908fb2174
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(META_locked, &(mp)->flag)
43
44 static inline void unlock_metapage(struct metapage *mp)
45 {
46 clear_bit(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 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 kmem_cache_t *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, uint 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, uint 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(void *foo, kmem_cache_t *cachep, unsigned long flags)
184 {
185 struct metapage *mp = (struct metapage *)foo;
186
187 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
188 SLAB_CTOR_CONSTRUCTOR) {
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
200 static inline struct metapage *alloc_metapage(gfp_t gfp_mask)
201 {
202 return mempool_alloc(metapage_mempool, gfp_mask);
203 }
204
205 static inline void free_metapage(struct metapage *mp)
206 {
207 mp->flag = 0;
208 set_bit(META_free, &mp->flag);
209
210 mempool_free(mp, metapage_mempool);
211 }
212
213 int __init metapage_init(void)
214 {
215 /*
216 * Allocate the metapage structures
217 */
218 metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage),
219 0, 0, init_once, NULL);
220 if (metapage_cache == NULL)
221 return -ENOMEM;
222
223 metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES,
224 metapage_cache);
225
226 if (metapage_mempool == NULL) {
227 kmem_cache_destroy(metapage_cache);
228 return -ENOMEM;
229 }
230
231 return 0;
232 }
233
234 void metapage_exit(void)
235 {
236 mempool_destroy(metapage_mempool);
237 kmem_cache_destroy(metapage_cache);
238 }
239
240 static inline void drop_metapage(struct page *page, struct metapage *mp)
241 {
242 if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) ||
243 test_bit(META_io, &mp->flag))
244 return;
245 remove_metapage(page, mp);
246 INCREMENT(mpStat.pagefree);
247 free_metapage(mp);
248 }
249
250 /*
251 * Metapage address space operations
252 */
253
254 static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
255 unsigned int *len)
256 {
257 int rc = 0;
258 int xflag;
259 s64 xaddr;
260 sector_t file_blocks = (inode->i_size + inode->i_blksize - 1) >>
261 inode->i_blkbits;
262
263 if (lblock >= file_blocks)
264 return 0;
265 if (lblock + *len > file_blocks)
266 *len = file_blocks - lblock;
267
268 if (inode->i_ino) {
269 rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0);
270 if ((rc == 0) && *len)
271 lblock = (sector_t)xaddr;
272 else
273 lblock = 0;
274 } /* else no mapping */
275
276 return lblock;
277 }
278
279 static void last_read_complete(struct page *page)
280 {
281 if (!PageError(page))
282 SetPageUptodate(page);
283 unlock_page(page);
284 }
285
286 static int metapage_read_end_io(struct bio *bio, unsigned int bytes_done,
287 int err)
288 {
289 struct page *page = bio->bi_private;
290
291 if (bio->bi_size)
292 return 1;
293
294 if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
295 printk(KERN_ERR "metapage_read_end_io: I/O error\n");
296 SetPageError(page);
297 }
298
299 dec_io(page, last_read_complete);
300 bio_put(bio);
301
302 return 0;
303 }
304
305 static void remove_from_logsync(struct metapage *mp)
306 {
307 struct jfs_log *log = mp->log;
308 unsigned long flags;
309 /*
310 * This can race. Recheck that log hasn't been set to null, and after
311 * acquiring logsync lock, recheck lsn
312 */
313 if (!log)
314 return;
315
316 LOGSYNC_LOCK(log, flags);
317 if (mp->lsn) {
318 mp->log = NULL;
319 mp->lsn = 0;
320 mp->clsn = 0;
321 log->count--;
322 list_del(&mp->synclist);
323 }
324 LOGSYNC_UNLOCK(log, flags);
325 }
326
327 static void last_write_complete(struct page *page)
328 {
329 struct metapage *mp;
330 unsigned int offset;
331
332 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
333 mp = page_to_mp(page, offset);
334 if (mp && test_bit(META_io, &mp->flag)) {
335 if (mp->lsn)
336 remove_from_logsync(mp);
337 clear_bit(META_io, &mp->flag);
338 }
339 /*
340 * I'd like to call drop_metapage here, but I don't think it's
341 * safe unless I have the page locked
342 */
343 }
344 end_page_writeback(page);
345 }
346
347 static int metapage_write_end_io(struct bio *bio, unsigned int bytes_done,
348 int err)
349 {
350 struct page *page = bio->bi_private;
351
352 BUG_ON(!PagePrivate(page));
353
354 if (bio->bi_size)
355 return 1;
356
357 if (! test_bit(BIO_UPTODATE, &bio->bi_flags)) {
358 printk(KERN_ERR "metapage_write_end_io: I/O error\n");
359 SetPageError(page);
360 }
361 dec_io(page, last_write_complete);
362 bio_put(bio);
363 return 0;
364 }
365
366 static int metapage_writepage(struct page *page, struct writeback_control *wbc)
367 {
368 struct bio *bio = NULL;
369 unsigned int block_offset; /* block offset of mp within page */
370 struct inode *inode = page->mapping->host;
371 unsigned int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
372 unsigned int len;
373 unsigned int xlen;
374 struct metapage *mp;
375 int redirty = 0;
376 sector_t lblock;
377 sector_t pblock;
378 sector_t next_block = 0;
379 sector_t page_start;
380 unsigned long bio_bytes = 0;
381 unsigned long bio_offset = 0;
382 unsigned int offset;
383
384 page_start = (sector_t)page->index <<
385 (PAGE_CACHE_SHIFT - inode->i_blkbits);
386 BUG_ON(!PageLocked(page));
387 BUG_ON(PageWriteback(page));
388
389 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
390 mp = page_to_mp(page, offset);
391
392 if (!mp || !test_bit(META_dirty, &mp->flag))
393 continue;
394
395 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) {
396 redirty = 1;
397 /*
398 * Make sure this page isn't blocked indefinitely.
399 * If the journal isn't undergoing I/O, push it
400 */
401 if (mp->log && !(mp->log->cflag & logGC_PAGEOUT))
402 jfs_flush_journal(mp->log, 0);
403 continue;
404 }
405
406 clear_bit(META_dirty, &mp->flag);
407 block_offset = offset >> inode->i_blkbits;
408 lblock = page_start + block_offset;
409 if (bio) {
410 if (xlen && lblock == next_block) {
411 /* Contiguous, in memory & on disk */
412 len = min(xlen, blocks_per_mp);
413 xlen -= len;
414 bio_bytes += len << inode->i_blkbits;
415 set_bit(META_io, &mp->flag);
416 continue;
417 }
418 /* Not contiguous */
419 if (bio_add_page(bio, page, bio_bytes, bio_offset) <
420 bio_bytes)
421 goto add_failed;
422 /*
423 * Increment counter before submitting i/o to keep
424 * count from hitting zero before we're through
425 */
426 inc_io(page);
427 if (!bio->bi_size)
428 goto dump_bio;
429 submit_bio(WRITE, bio);
430 bio = NULL;
431 } else {
432 set_page_writeback(page);
433 inc_io(page);
434 }
435 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
436 pblock = metapage_get_blocks(inode, lblock, &xlen);
437 if (!pblock) {
438 /* Need better error handling */
439 printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
440 dec_io(page, last_write_complete);
441 continue;
442 }
443 set_bit(META_io, &mp->flag);
444 len = min(xlen, (uint) JFS_SBI(inode->i_sb)->nbperpage);
445
446 bio = bio_alloc(GFP_NOFS, 1);
447 bio->bi_bdev = inode->i_sb->s_bdev;
448 bio->bi_sector = pblock << (inode->i_blkbits - 9);
449 bio->bi_end_io = metapage_write_end_io;
450 bio->bi_private = page;
451
452 /* Don't call bio_add_page yet, we may add to this vec */
453 bio_offset = offset;
454 bio_bytes = len << inode->i_blkbits;
455
456 xlen -= len;
457 next_block = lblock + len;
458 }
459 if (bio) {
460 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
461 goto add_failed;
462 if (!bio->bi_size)
463 goto dump_bio;
464
465 submit_bio(WRITE, bio);
466 }
467 if (redirty)
468 redirty_page_for_writepage(wbc, page);
469
470 unlock_page(page);
471
472 return 0;
473 add_failed:
474 /* We should never reach here, since we're only adding one vec */
475 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
476 goto skip;
477 dump_bio:
478 dump_mem("bio", bio, sizeof(*bio));
479 skip:
480 bio_put(bio);
481 unlock_page(page);
482 dec_io(page, last_write_complete);
483
484 return -EIO;
485 }
486
487 static int metapage_readpage(struct file *fp, struct page *page)
488 {
489 struct inode *inode = page->mapping->host;
490 struct bio *bio = NULL;
491 unsigned int block_offset;
492 unsigned int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits;
493 sector_t page_start; /* address of page in fs blocks */
494 sector_t pblock;
495 unsigned int xlen;
496 unsigned int len;
497 unsigned int offset;
498
499 BUG_ON(!PageLocked(page));
500 page_start = (sector_t)page->index <<
501 (PAGE_CACHE_SHIFT - inode->i_blkbits);
502
503 block_offset = 0;
504 while (block_offset < blocks_per_page) {
505 xlen = blocks_per_page - block_offset;
506 pblock = metapage_get_blocks(inode, page_start + block_offset,
507 &xlen);
508 if (pblock) {
509 if (!PagePrivate(page))
510 insert_metapage(page, NULL);
511 inc_io(page);
512 if (bio)
513 submit_bio(READ, bio);
514
515 bio = bio_alloc(GFP_NOFS, 1);
516 bio->bi_bdev = inode->i_sb->s_bdev;
517 bio->bi_sector = pblock << (inode->i_blkbits - 9);
518 bio->bi_end_io = metapage_read_end_io;
519 bio->bi_private = page;
520 len = xlen << inode->i_blkbits;
521 offset = block_offset << inode->i_blkbits;
522 if (bio_add_page(bio, page, len, offset) < len)
523 goto add_failed;
524 block_offset += xlen;
525 } else
526 block_offset++;
527 }
528 if (bio)
529 submit_bio(READ, bio);
530 else
531 unlock_page(page);
532
533 return 0;
534
535 add_failed:
536 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
537 bio_put(bio);
538 dec_io(page, last_read_complete);
539 return -EIO;
540 }
541
542 static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
543 {
544 struct metapage *mp;
545 int ret = 1;
546 unsigned int offset;
547
548 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
549 mp = page_to_mp(page, offset);
550
551 if (!mp)
552 continue;
553
554 jfs_info("metapage_releasepage: mp = 0x%p", mp);
555 if (mp->count || mp->nohomeok ||
556 test_bit(META_dirty, &mp->flag)) {
557 jfs_info("count = %ld, nohomeok = %d", mp->count,
558 mp->nohomeok);
559 ret = 0;
560 continue;
561 }
562 if (mp->lsn)
563 remove_from_logsync(mp);
564 remove_metapage(page, mp);
565 INCREMENT(mpStat.pagefree);
566 free_metapage(mp);
567 }
568 return ret;
569 }
570
571 static void metapage_invalidatepage(struct page *page, unsigned long offset)
572 {
573 BUG_ON(offset);
574
575 BUG_ON(PageWriteback(page));
576
577 metapage_releasepage(page, 0);
578 }
579
580 const struct address_space_operations jfs_metapage_aops = {
581 .readpage = metapage_readpage,
582 .writepage = metapage_writepage,
583 .sync_page = block_sync_page,
584 .releasepage = metapage_releasepage,
585 .invalidatepage = metapage_invalidatepage,
586 .set_page_dirty = __set_page_dirty_nobuffers,
587 };
588
589 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
590 unsigned int size, int absolute,
591 unsigned long new)
592 {
593 int l2BlocksPerPage;
594 int l2bsize;
595 struct address_space *mapping;
596 struct metapage *mp = NULL;
597 struct page *page;
598 unsigned long page_index;
599 unsigned long page_offset;
600
601 jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
602 inode->i_ino, lblock, absolute);
603
604 l2bsize = inode->i_blkbits;
605 l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
606 page_index = lblock >> l2BlocksPerPage;
607 page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
608 if ((page_offset + size) > PAGE_CACHE_SIZE) {
609 jfs_err("MetaData crosses page boundary!!");
610 jfs_err("lblock = %lx, size = %d", lblock, size);
611 dump_stack();
612 return NULL;
613 }
614 if (absolute)
615 mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
616 else {
617 /*
618 * If an nfs client tries to read an inode that is larger
619 * than any existing inodes, we may try to read past the
620 * end of the inode map
621 */
622 if ((lblock << inode->i_blkbits) >= inode->i_size)
623 return NULL;
624 mapping = inode->i_mapping;
625 }
626
627 if (new && (PSIZE == PAGE_CACHE_SIZE)) {
628 page = grab_cache_page(mapping, page_index);
629 if (!page) {
630 jfs_err("grab_cache_page failed!");
631 return NULL;
632 }
633 SetPageUptodate(page);
634 } else {
635 page = read_mapping_page(mapping, page_index, NULL);
636 if (IS_ERR(page) || !PageUptodate(page)) {
637 jfs_err("read_mapping_page failed!");
638 return NULL;
639 }
640 lock_page(page);
641 }
642
643 mp = page_to_mp(page, page_offset);
644 if (mp) {
645 if (mp->logical_size != size) {
646 jfs_error(inode->i_sb,
647 "__get_metapage: mp->logical_size != size");
648 jfs_err("logical_size = %d, size = %d",
649 mp->logical_size, size);
650 dump_stack();
651 goto unlock;
652 }
653 mp->count++;
654 lock_metapage(mp);
655 if (test_bit(META_discard, &mp->flag)) {
656 if (!new) {
657 jfs_error(inode->i_sb,
658 "__get_metapage: using a "
659 "discarded metapage");
660 discard_metapage(mp);
661 goto unlock;
662 }
663 clear_bit(META_discard, &mp->flag);
664 }
665 } else {
666 INCREMENT(mpStat.pagealloc);
667 mp = alloc_metapage(GFP_NOFS);
668 mp->page = page;
669 mp->flag = 0;
670 mp->xflag = COMMIT_PAGE;
671 mp->count = 1;
672 mp->nohomeok = 0;
673 mp->logical_size = size;
674 mp->data = page_address(page) + page_offset;
675 mp->index = lblock;
676 if (unlikely(insert_metapage(page, mp))) {
677 free_metapage(mp);
678 goto unlock;
679 }
680 lock_metapage(mp);
681 }
682
683 if (new) {
684 jfs_info("zeroing mp = 0x%p", mp);
685 memset(mp->data, 0, PSIZE);
686 }
687
688 unlock_page(page);
689 jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
690 return mp;
691
692 unlock:
693 unlock_page(page);
694 return NULL;
695 }
696
697 void grab_metapage(struct metapage * mp)
698 {
699 jfs_info("grab_metapage: mp = 0x%p", mp);
700 page_cache_get(mp->page);
701 lock_page(mp->page);
702 mp->count++;
703 lock_metapage(mp);
704 unlock_page(mp->page);
705 }
706
707 void force_metapage(struct metapage *mp)
708 {
709 struct page *page = mp->page;
710 jfs_info("force_metapage: mp = 0x%p", mp);
711 set_bit(META_forcewrite, &mp->flag);
712 clear_bit(META_sync, &mp->flag);
713 page_cache_get(page);
714 lock_page(page);
715 set_page_dirty(page);
716 write_one_page(page, 1);
717 clear_bit(META_forcewrite, &mp->flag);
718 page_cache_release(page);
719 }
720
721 void hold_metapage(struct metapage *mp)
722 {
723 lock_page(mp->page);
724 }
725
726 void put_metapage(struct metapage *mp)
727 {
728 if (mp->count || mp->nohomeok) {
729 /* Someone else will release this */
730 unlock_page(mp->page);
731 return;
732 }
733 page_cache_get(mp->page);
734 mp->count++;
735 lock_metapage(mp);
736 unlock_page(mp->page);
737 release_metapage(mp);
738 }
739
740 void release_metapage(struct metapage * mp)
741 {
742 struct page *page = mp->page;
743 jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
744
745 BUG_ON(!page);
746
747 lock_page(page);
748 unlock_metapage(mp);
749
750 assert(mp->count);
751 if (--mp->count || mp->nohomeok) {
752 unlock_page(page);
753 page_cache_release(page);
754 return;
755 }
756
757 if (test_bit(META_dirty, &mp->flag)) {
758 set_page_dirty(page);
759 if (test_bit(META_sync, &mp->flag)) {
760 clear_bit(META_sync, &mp->flag);
761 write_one_page(page, 1);
762 lock_page(page); /* write_one_page unlocks the page */
763 }
764 } else if (mp->lsn) /* discard_metapage doesn't remove it */
765 remove_from_logsync(mp);
766
767 #if MPS_PER_PAGE == 1
768 /*
769 * If we know this is the only thing in the page, we can throw
770 * the page out of the page cache. If pages are larger, we
771 * don't want to do this.
772 */
773
774 /* Retest mp->count since we may have released page lock */
775 if (test_bit(META_discard, &mp->flag) && !mp->count) {
776 clear_page_dirty(page);
777 ClearPageUptodate(page);
778 }
779 #else
780 /* Try to keep metapages from using up too much memory */
781 drop_metapage(page, mp);
782 #endif
783 unlock_page(page);
784 page_cache_release(page);
785 }
786
787 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
788 {
789 sector_t lblock;
790 int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
791 int BlocksPerPage = 1 << l2BlocksPerPage;
792 /* All callers are interested in block device's mapping */
793 struct address_space *mapping =
794 JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
795 struct metapage *mp;
796 struct page *page;
797 unsigned int offset;
798
799 /*
800 * Mark metapages to discard. They will eventually be
801 * released, but should not be written.
802 */
803 for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
804 lblock += BlocksPerPage) {
805 page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
806 if (!page)
807 continue;
808 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
809 mp = page_to_mp(page, offset);
810 if (!mp)
811 continue;
812 if (mp->index < addr)
813 continue;
814 if (mp->index >= addr + len)
815 break;
816
817 clear_bit(META_dirty, &mp->flag);
818 set_bit(META_discard, &mp->flag);
819 if (mp->lsn)
820 remove_from_logsync(mp);
821 }
822 unlock_page(page);
823 page_cache_release(page);
824 }
825 }
826
827 #ifdef CONFIG_JFS_STATISTICS
828 int jfs_mpstat_read(char *buffer, char **start, off_t offset, int length,
829 int *eof, void *data)
830 {
831 int len = 0;
832 off_t begin;
833
834 len += sprintf(buffer,
835 "JFS Metapage statistics\n"
836 "=======================\n"
837 "page allocations = %d\n"
838 "page frees = %d\n"
839 "lock waits = %d\n",
840 mpStat.pagealloc,
841 mpStat.pagefree,
842 mpStat.lockwait);
843
844 begin = offset;
845 *start = buffer + begin;
846 len -= begin;
847
848 if (len > length)
849 len = length;
850 else
851 *eof = 1;
852
853 if (len < 0)
854 len = 0;
855
856 return len;
857 }
858 #endif
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