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dm mpath: check if scsi_dh module already loaded before trying to load
[zen-stable.git] / fs / jfs / jfs_metapage.c
blob6740d34cd82b802e948b8760fcf13954a8a12ad2
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/slab.h>
25 #include <linux/init.h>
26 #include <linux/buffer_head.h>
27 #include <linux/mempool.h>
28 #include <linux/seq_file.h>
29 #include "jfs_incore.h"
30 #include "jfs_superblock.h"
31 #include "jfs_filsys.h"
32 #include "jfs_metapage.h"
33 #include "jfs_txnmgr.h"
34 #include "jfs_debug.h"
35
36 #ifdef CONFIG_JFS_STATISTICS
37 static struct {
38 uint pagealloc; /* # of page allocations */
39 uint pagefree; /* # of page frees */
40 uint lockwait; /* # of sleeping lock_metapage() calls */
41 } mpStat;
42 #endif
43
44 #define metapage_locked(mp) test_bit(META_locked, &(mp)->flag)
45 #define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag)
46
47 static inline void unlock_metapage(struct metapage *mp)
48 {
49 clear_bit_unlock(META_locked, &mp->flag);
50 wake_up(&mp->wait);
51 }
52
53 static inline void __lock_metapage(struct metapage *mp)
54 {
55 DECLARE_WAITQUEUE(wait, current);
56 INCREMENT(mpStat.lockwait);
57 add_wait_queue_exclusive(&mp->wait, &wait);
58 do {
59 set_current_state(TASK_UNINTERRUPTIBLE);
60 if (metapage_locked(mp)) {
61 unlock_page(mp->page);
62 io_schedule();
63 lock_page(mp->page);
64 }
65 } while (trylock_metapage(mp));
66 __set_current_state(TASK_RUNNING);
67 remove_wait_queue(&mp->wait, &wait);
68 }
69
70 /*
71 * Must have mp->page locked
72 */
73 static inline void lock_metapage(struct metapage *mp)
74 {
75 if (trylock_metapage(mp))
76 __lock_metapage(mp);
77 }
78
79 #define METAPOOL_MIN_PAGES 32
80 static struct kmem_cache *metapage_cache;
81 static mempool_t *metapage_mempool;
82
83 #define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE)
84
85 #if MPS_PER_PAGE > 1
86
87 struct meta_anchor {
88 int mp_count;
89 atomic_t io_count;
90 struct metapage *mp[MPS_PER_PAGE];
91 };
92 #define mp_anchor(page) ((struct meta_anchor *)page_private(page))
93
94 static inline struct metapage *page_to_mp(struct page *page, int offset)
95 {
96 if (!PagePrivate(page))
97 return NULL;
98 return mp_anchor(page)->mp[offset >> L2PSIZE];
99 }
100
101 static inline int insert_metapage(struct page *page, struct metapage *mp)
102 {
103 struct meta_anchor *a;
104 int index;
105 int l2mp_blocks; /* log2 blocks per metapage */
106
107 if (PagePrivate(page))
108 a = mp_anchor(page);
109 else {
110 a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS);
111 if (!a)
112 return -ENOMEM;
113 set_page_private(page, (unsigned long)a);
114 SetPagePrivate(page);
115 kmap(page);
116 }
117
118 if (mp) {
119 l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
120 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
121 a->mp_count++;
122 a->mp[index] = mp;
123 }
124
125 return 0;
126 }
127
128 static inline void remove_metapage(struct page *page, struct metapage *mp)
129 {
130 struct meta_anchor *a = mp_anchor(page);
131 int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
132 int index;
133
134 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
135
136 BUG_ON(a->mp[index] != mp);
137
138 a->mp[index] = NULL;
139 if (--a->mp_count == 0) {
140 kfree(a);
141 set_page_private(page, 0);
142 ClearPagePrivate(page);
143 kunmap(page);
144 }
145 }
146
147 static inline void inc_io(struct page *page)
148 {
149 atomic_inc(&mp_anchor(page)->io_count);
150 }
151
152 static inline void dec_io(struct page *page, void (*handler) (struct page *))
153 {
154 if (atomic_dec_and_test(&mp_anchor(page)->io_count))
155 handler(page);
156 }
157
158 #else
159 static inline struct metapage *page_to_mp(struct page *page, int offset)
160 {
161 return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL;
162 }
163
164 static inline int insert_metapage(struct page *page, struct metapage *mp)
165 {
166 if (mp) {
167 set_page_private(page, (unsigned long)mp);
168 SetPagePrivate(page);
169 kmap(page);
170 }
171 return 0;
172 }
173
174 static inline void remove_metapage(struct page *page, struct metapage *mp)
175 {
176 set_page_private(page, 0);
177 ClearPagePrivate(page);
178 kunmap(page);
179 }
180
181 #define inc_io(page) do {} while(0)
182 #define dec_io(page, handler) handler(page)
183
184 #endif
185
186 static void init_once(void *foo)
187 {
188 struct metapage *mp = (struct metapage *)foo;
189
190 mp->lid = 0;
191 mp->lsn = 0;
192 mp->flag = 0;
193 mp->data = NULL;
194 mp->clsn = 0;
195 mp->log = NULL;
196 set_bit(META_free, &mp->flag);
197 init_waitqueue_head(&mp->wait);
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);
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 int *len)
256 {
257 int rc = 0;
258 int xflag;
259 s64 xaddr;
260 sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 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 void metapage_read_end_io(struct bio *bio, int err)
287 {
288 struct page *page = bio->bi_private;
289
290 if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
291 printk(KERN_ERR "metapage_read_end_io: I/O error\n");
292 SetPageError(page);
293 }
294
295 dec_io(page, last_read_complete);
296 bio_put(bio);
297 }
298
299 static void remove_from_logsync(struct metapage *mp)
300 {
301 struct jfs_log *log = mp->log;
302 unsigned long flags;
303 /*
304 * This can race. Recheck that log hasn't been set to null, and after
305 * acquiring logsync lock, recheck lsn
306 */
307 if (!log)
308 return;
309
310 LOGSYNC_LOCK(log, flags);
311 if (mp->lsn) {
312 mp->log = NULL;
313 mp->lsn = 0;
314 mp->clsn = 0;
315 log->count--;
316 list_del(&mp->synclist);
317 }
318 LOGSYNC_UNLOCK(log, flags);
319 }
320
321 static void last_write_complete(struct page *page)
322 {
323 struct metapage *mp;
324 unsigned int offset;
325
326 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
327 mp = page_to_mp(page, offset);
328 if (mp && test_bit(META_io, &mp->flag)) {
329 if (mp->lsn)
330 remove_from_logsync(mp);
331 clear_bit(META_io, &mp->flag);
332 }
333 /*
334 * I'd like to call drop_metapage here, but I don't think it's
335 * safe unless I have the page locked
336 */
337 }
338 end_page_writeback(page);
339 }
340
341 static void metapage_write_end_io(struct bio *bio, int err)
342 {
343 struct page *page = bio->bi_private;
344
345 BUG_ON(!PagePrivate(page));
346
347 if (! test_bit(BIO_UPTODATE, &bio->bi_flags)) {
348 printk(KERN_ERR "metapage_write_end_io: I/O error\n");
349 SetPageError(page);
350 }
351 dec_io(page, last_write_complete);
352 bio_put(bio);
353 }
354
355 static int metapage_writepage(struct page *page, struct writeback_control *wbc)
356 {
357 struct bio *bio = NULL;
358 int block_offset; /* block offset of mp within page */
359 struct inode *inode = page->mapping->host;
360 int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
361 int len;
362 int xlen;
363 struct metapage *mp;
364 int redirty = 0;
365 sector_t lblock;
366 int nr_underway = 0;
367 sector_t pblock;
368 sector_t next_block = 0;
369 sector_t page_start;
370 unsigned long bio_bytes = 0;
371 unsigned long bio_offset = 0;
372 int offset;
373 int bad_blocks = 0;
374
375 page_start = (sector_t)page->index <<
376 (PAGE_CACHE_SHIFT - inode->i_blkbits);
377 BUG_ON(!PageLocked(page));
378 BUG_ON(PageWriteback(page));
379 set_page_writeback(page);
380
381 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
382 mp = page_to_mp(page, offset);
383
384 if (!mp || !test_bit(META_dirty, &mp->flag))
385 continue;
386
387 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) {
388 redirty = 1;
389 /*
390 * Make sure this page isn't blocked indefinitely.
391 * If the journal isn't undergoing I/O, push it
392 */
393 if (mp->log && !(mp->log->cflag & logGC_PAGEOUT))
394 jfs_flush_journal(mp->log, 0);
395 continue;
396 }
397
398 clear_bit(META_dirty, &mp->flag);
399 set_bit(META_io, &mp->flag);
400 block_offset = offset >> inode->i_blkbits;
401 lblock = page_start + block_offset;
402 if (bio) {
403 if (xlen && lblock == next_block) {
404 /* Contiguous, in memory & on disk */
405 len = min(xlen, blocks_per_mp);
406 xlen -= len;
407 bio_bytes += len << inode->i_blkbits;
408 continue;
409 }
410 /* Not contiguous */
411 if (bio_add_page(bio, page, bio_bytes, bio_offset) <
412 bio_bytes)
413 goto add_failed;
414 /*
415 * Increment counter before submitting i/o to keep
416 * count from hitting zero before we're through
417 */
418 inc_io(page);
419 if (!bio->bi_size)
420 goto dump_bio;
421 submit_bio(WRITE, bio);
422 nr_underway++;
423 bio = NULL;
424 } else
425 inc_io(page);
426 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
427 pblock = metapage_get_blocks(inode, lblock, &xlen);
428 if (!pblock) {
429 printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
430 /*
431 * We already called inc_io(), but can't cancel it
432 * with dec_io() until we're done with the page
433 */
434 bad_blocks++;
435 continue;
436 }
437 len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage);
438
439 bio = bio_alloc(GFP_NOFS, 1);
440 bio->bi_bdev = inode->i_sb->s_bdev;
441 bio->bi_sector = pblock << (inode->i_blkbits - 9);
442 bio->bi_end_io = metapage_write_end_io;
443 bio->bi_private = page;
444
445 /* Don't call bio_add_page yet, we may add to this vec */
446 bio_offset = offset;
447 bio_bytes = len << inode->i_blkbits;
448
449 xlen -= len;
450 next_block = lblock + len;
451 }
452 if (bio) {
453 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
454 goto add_failed;
455 if (!bio->bi_size)
456 goto dump_bio;
457
458 submit_bio(WRITE, bio);
459 nr_underway++;
460 }
461 if (redirty)
462 redirty_page_for_writepage(wbc, page);
463
464 unlock_page(page);
465
466 if (bad_blocks)
467 goto err_out;
468
469 if (nr_underway == 0)
470 end_page_writeback(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 print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16,
479 4, bio, sizeof(*bio), 0);
480 skip:
481 bio_put(bio);
482 unlock_page(page);
483 dec_io(page, last_write_complete);
484 err_out:
485 while (bad_blocks--)
486 dec_io(page, last_write_complete);
487 return -EIO;
488 }
489
490 static int metapage_readpage(struct file *fp, struct page *page)
491 {
492 struct inode *inode = page->mapping->host;
493 struct bio *bio = NULL;
494 int block_offset;
495 int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits;
496 sector_t page_start; /* address of page in fs blocks */
497 sector_t pblock;
498 int xlen;
499 unsigned int len;
500 int offset;
501
502 BUG_ON(!PageLocked(page));
503 page_start = (sector_t)page->index <<
504 (PAGE_CACHE_SHIFT - inode->i_blkbits);
505
506 block_offset = 0;
507 while (block_offset < blocks_per_page) {
508 xlen = blocks_per_page - block_offset;
509 pblock = metapage_get_blocks(inode, page_start + block_offset,
510 &xlen);
511 if (pblock) {
512 if (!PagePrivate(page))
513 insert_metapage(page, NULL);
514 inc_io(page);
515 if (bio)
516 submit_bio(READ, bio);
517
518 bio = bio_alloc(GFP_NOFS, 1);
519 bio->bi_bdev = inode->i_sb->s_bdev;
520 bio->bi_sector = pblock << (inode->i_blkbits - 9);
521 bio->bi_end_io = metapage_read_end_io;
522 bio->bi_private = page;
523 len = xlen << inode->i_blkbits;
524 offset = block_offset << inode->i_blkbits;
525 if (bio_add_page(bio, page, len, offset) < len)
526 goto add_failed;
527 block_offset += xlen;
528 } else
529 block_offset++;
530 }
531 if (bio)
532 submit_bio(READ, bio);
533 else
534 unlock_page(page);
535
536 return 0;
537
538 add_failed:
539 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
540 bio_put(bio);
541 dec_io(page, last_read_complete);
542 return -EIO;
543 }
544
545 static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
546 {
547 struct metapage *mp;
548 int ret = 1;
549 int offset;
550
551 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
552 mp = page_to_mp(page, offset);
553
554 if (!mp)
555 continue;
556
557 jfs_info("metapage_releasepage: mp = 0x%p", mp);
558 if (mp->count || mp->nohomeok ||
559 test_bit(META_dirty, &mp->flag)) {
560 jfs_info("count = %ld, nohomeok = %d", mp->count,
561 mp->nohomeok);
562 ret = 0;
563 continue;
564 }
565 if (mp->lsn)
566 remove_from_logsync(mp);
567 remove_metapage(page, mp);
568 INCREMENT(mpStat.pagefree);
569 free_metapage(mp);
570 }
571 return ret;
572 }
573
574 static void metapage_invalidatepage(struct page *page, unsigned long offset)
575 {
576 BUG_ON(offset);
577
578 BUG_ON(PageWriteback(page));
579
580 metapage_releasepage(page, 0);
581 }
582
583 const struct address_space_operations jfs_metapage_aops = {
584 .readpage = metapage_readpage,
585 .writepage = metapage_writepage,
586 .releasepage = metapage_releasepage,
587 .invalidatepage = metapage_invalidatepage,
588 .set_page_dirty = __set_page_dirty_nobuffers,
589 };
590
591 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
592 unsigned int size, int absolute,
593 unsigned long new)
594 {
595 int l2BlocksPerPage;
596 int l2bsize;
597 struct address_space *mapping;
598 struct metapage *mp = NULL;
599 struct page *page;
600 unsigned long page_index;
601 unsigned long page_offset;
602
603 jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
604 inode->i_ino, lblock, absolute);
605
606 l2bsize = inode->i_blkbits;
607 l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
608 page_index = lblock >> l2BlocksPerPage;
609 page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
610 if ((page_offset + size) > PAGE_CACHE_SIZE) {
611 jfs_err("MetaData crosses page boundary!!");
612 jfs_err("lblock = %lx, size = %d", lblock, size);
613 dump_stack();
614 return NULL;
615 }
616 if (absolute)
617 mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
618 else {
619 /*
620 * If an nfs client tries to read an inode that is larger
621 * than any existing inodes, we may try to read past the
622 * end of the inode map
623 */
624 if ((lblock << inode->i_blkbits) >= inode->i_size)
625 return NULL;
626 mapping = inode->i_mapping;
627 }
628
629 if (new && (PSIZE == PAGE_CACHE_SIZE)) {
630 page = grab_cache_page(mapping, page_index);
631 if (!page) {
632 jfs_err("grab_cache_page failed!");
633 return NULL;
634 }
635 SetPageUptodate(page);
636 } else {
637 page = read_mapping_page(mapping, page_index, NULL);
638 if (IS_ERR(page) || !PageUptodate(page)) {
639 jfs_err("read_mapping_page failed!");
640 return NULL;
641 }
642 lock_page(page);
643 }
644
645 mp = page_to_mp(page, page_offset);
646 if (mp) {
647 if (mp->logical_size != size) {
648 jfs_error(inode->i_sb,
649 "__get_metapage: mp->logical_size != size");
650 jfs_err("logical_size = %d, size = %d",
651 mp->logical_size, size);
652 dump_stack();
653 goto unlock;
654 }
655 mp->count++;
656 lock_metapage(mp);
657 if (test_bit(META_discard, &mp->flag)) {
658 if (!new) {
659 jfs_error(inode->i_sb,
660 "__get_metapage: using a "
661 "discarded metapage");
662 discard_metapage(mp);
663 goto unlock;
664 }
665 clear_bit(META_discard, &mp->flag);
666 }
667 } else {
668 INCREMENT(mpStat.pagealloc);
669 mp = alloc_metapage(GFP_NOFS);
670 mp->page = page;
671 mp->flag = 0;
672 mp->xflag = COMMIT_PAGE;
673 mp->count = 1;
674 mp->nohomeok = 0;
675 mp->logical_size = size;
676 mp->data = page_address(page) + page_offset;
677 mp->index = lblock;
678 if (unlikely(insert_metapage(page, mp))) {
679 free_metapage(mp);
680 goto unlock;
681 }
682 lock_metapage(mp);
683 }
684
685 if (new) {
686 jfs_info("zeroing mp = 0x%p", mp);
687 memset(mp->data, 0, PSIZE);
688 }
689
690 unlock_page(page);
691 jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
692 return mp;
693
694 unlock:
695 unlock_page(page);
696 return NULL;
697 }
698
699 void grab_metapage(struct metapage * mp)
700 {
701 jfs_info("grab_metapage: mp = 0x%p", mp);
702 page_cache_get(mp->page);
703 lock_page(mp->page);
704 mp->count++;
705 lock_metapage(mp);
706 unlock_page(mp->page);
707 }
708
709 void force_metapage(struct metapage *mp)
710 {
711 struct page *page = mp->page;
712 jfs_info("force_metapage: mp = 0x%p", mp);
713 set_bit(META_forcewrite, &mp->flag);
714 clear_bit(META_sync, &mp->flag);
715 page_cache_get(page);
716 lock_page(page);
717 set_page_dirty(page);
718 write_one_page(page, 1);
719 clear_bit(META_forcewrite, &mp->flag);
720 page_cache_release(page);
721 }
722
723 void hold_metapage(struct metapage *mp)
724 {
725 lock_page(mp->page);
726 }
727
728 void put_metapage(struct metapage *mp)
729 {
730 if (mp->count || mp->nohomeok) {
731 /* Someone else will release this */
732 unlock_page(mp->page);
733 return;
734 }
735 page_cache_get(mp->page);
736 mp->count++;
737 lock_metapage(mp);
738 unlock_page(mp->page);
739 release_metapage(mp);
740 }
741
742 void release_metapage(struct metapage * mp)
743 {
744 struct page *page = mp->page;
745 jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
746
747 BUG_ON(!page);
748
749 lock_page(page);
750 unlock_metapage(mp);
751
752 assert(mp->count);
753 if (--mp->count || mp->nohomeok) {
754 unlock_page(page);
755 page_cache_release(page);
756 return;
757 }
758
759 if (test_bit(META_dirty, &mp->flag)) {
760 set_page_dirty(page);
761 if (test_bit(META_sync, &mp->flag)) {
762 clear_bit(META_sync, &mp->flag);
763 write_one_page(page, 1);
764 lock_page(page); /* write_one_page unlocks the page */
765 }
766 } else if (mp->lsn) /* discard_metapage doesn't remove it */
767 remove_from_logsync(mp);
768
769 /* Try to keep metapages from using up too much memory */
770 drop_metapage(page, mp);
771
772 unlock_page(page);
773 page_cache_release(page);
774 }
775
776 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
777 {
778 sector_t lblock;
779 int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
780 int BlocksPerPage = 1 << l2BlocksPerPage;
781 /* All callers are interested in block device's mapping */
782 struct address_space *mapping =
783 JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
784 struct metapage *mp;
785 struct page *page;
786 unsigned int offset;
787
788 /*
789 * Mark metapages to discard. They will eventually be
790 * released, but should not be written.
791 */
792 for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
793 lblock += BlocksPerPage) {
794 page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
795 if (!page)
796 continue;
797 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
798 mp = page_to_mp(page, offset);
799 if (!mp)
800 continue;
801 if (mp->index < addr)
802 continue;
803 if (mp->index >= addr + len)
804 break;
805
806 clear_bit(META_dirty, &mp->flag);
807 set_bit(META_discard, &mp->flag);
808 if (mp->lsn)
809 remove_from_logsync(mp);
810 }
811 unlock_page(page);
812 page_cache_release(page);
813 }
814 }
815
816 #ifdef CONFIG_JFS_STATISTICS
817 static int jfs_mpstat_proc_show(struct seq_file *m, void *v)
818 {
819 seq_printf(m,
820 "JFS Metapage statistics\n"
821 "=======================\n"
822 "page allocations = %d\n"
823 "page frees = %d\n"
824 "lock waits = %d\n",
825 mpStat.pagealloc,
826 mpStat.pagefree,
827 mpStat.lockwait);
828 return 0;
829 }
830
831 static int jfs_mpstat_proc_open(struct inode *inode, struct file *file)
832 {
833 return single_open(file, jfs_mpstat_proc_show, NULL);
834 }
835
836 const struct file_operations jfs_mpstat_proc_fops = {
837 .owner = THIS_MODULE,
838 .open = jfs_mpstat_proc_open,
839 .read = seq_read,
840 .llseek = seq_lseek,
841 .release = single_release,
842 };
843 #endif