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Linux/fs/jfs/jfs_metapage.c

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

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