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