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[mirror_ubuntu-bionic-kernel.git] / fs / jfs / jfs_metapage.c
1 /*
2 * Copyright (C) International Business Machines Corp., 2000-2003
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/init.h>
22 #include <linux/buffer_head.h>
23 #include <linux/mempool.h>
24 #include <linux/delay.h>
25 #include "jfs_incore.h"
26 #include "jfs_superblock.h"
27 #include "jfs_filsys.h"
28 #include "jfs_metapage.h"
29 #include "jfs_txnmgr.h"
30 #include "jfs_debug.h"
31
32 static DEFINE_SPINLOCK(meta_lock);
33
34 #ifdef CONFIG_JFS_STATISTICS
35 static struct {
36 uint pagealloc; /* # of page allocations */
37 uint pagefree; /* # of page frees */
38 uint lockwait; /* # of sleeping lock_metapage() calls */
39 } mpStat;
40 #endif
41
42
43 #define HASH_BITS 10 /* This makes hash_table 1 4K page */
44 #define HASH_SIZE (1 << HASH_BITS)
45 static struct metapage **hash_table = NULL;
46 static unsigned long hash_order;
47
48
49 static inline int metapage_locked(struct metapage *mp)
50 {
51 return test_bit(META_locked, &mp->flag);
52 }
53
54 static inline int trylock_metapage(struct metapage *mp)
55 {
56 return test_and_set_bit(META_locked, &mp->flag);
57 }
58
59 static inline void unlock_metapage(struct metapage *mp)
60 {
61 clear_bit(META_locked, &mp->flag);
62 wake_up(&mp->wait);
63 }
64
65 static void __lock_metapage(struct metapage *mp)
66 {
67 DECLARE_WAITQUEUE(wait, current);
68
69 INCREMENT(mpStat.lockwait);
70
71 add_wait_queue_exclusive(&mp->wait, &wait);
72 do {
73 set_current_state(TASK_UNINTERRUPTIBLE);
74 if (metapage_locked(mp)) {
75 spin_unlock(&meta_lock);
76 schedule();
77 spin_lock(&meta_lock);
78 }
79 } while (trylock_metapage(mp));
80 __set_current_state(TASK_RUNNING);
81 remove_wait_queue(&mp->wait, &wait);
82 }
83
84 /* needs meta_lock */
85 static inline void lock_metapage(struct metapage *mp)
86 {
87 if (trylock_metapage(mp))
88 __lock_metapage(mp);
89 }
90
91 #define METAPOOL_MIN_PAGES 32
92 static kmem_cache_t *metapage_cache;
93 static mempool_t *metapage_mempool;
94
95 static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
96 {
97 struct metapage *mp = (struct metapage *)foo;
98
99 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
100 SLAB_CTOR_CONSTRUCTOR) {
101 mp->lid = 0;
102 mp->lsn = 0;
103 mp->flag = 0;
104 mp->data = NULL;
105 mp->clsn = 0;
106 mp->log = NULL;
107 set_bit(META_free, &mp->flag);
108 init_waitqueue_head(&mp->wait);
109 }
110 }
111
112 static inline struct metapage *alloc_metapage(int gfp_mask)
113 {
114 return mempool_alloc(metapage_mempool, gfp_mask);
115 }
116
117 static inline void free_metapage(struct metapage *mp)
118 {
119 mp->flag = 0;
120 set_bit(META_free, &mp->flag);
121
122 mempool_free(mp, metapage_mempool);
123 }
124
125 int __init metapage_init(void)
126 {
127 /*
128 * Allocate the metapage structures
129 */
130 metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage),
131 0, 0, init_once, NULL);
132 if (metapage_cache == NULL)
133 return -ENOMEM;
134
135 metapage_mempool = mempool_create(METAPOOL_MIN_PAGES, mempool_alloc_slab,
136 mempool_free_slab, metapage_cache);
137
138 if (metapage_mempool == NULL) {
139 kmem_cache_destroy(metapage_cache);
140 return -ENOMEM;
141 }
142 /*
143 * Now the hash list
144 */
145 for (hash_order = 0;
146 ((PAGE_SIZE << hash_order) / sizeof(void *)) < HASH_SIZE;
147 hash_order++);
148 hash_table =
149 (struct metapage **) __get_free_pages(GFP_KERNEL, hash_order);
150 assert(hash_table);
151 memset(hash_table, 0, PAGE_SIZE << hash_order);
152
153 return 0;
154 }
155
156 void metapage_exit(void)
157 {
158 mempool_destroy(metapage_mempool);
159 kmem_cache_destroy(metapage_cache);
160 }
161
162 /*
163 * Basically same hash as in pagemap.h, but using our hash table
164 */
165 static struct metapage **meta_hash(struct address_space *mapping,
166 unsigned long index)
167 {
168 #define i (((unsigned long)mapping)/ \
169 (sizeof(struct inode) & ~(sizeof(struct inode) -1 )))
170 #define s(x) ((x) + ((x) >> HASH_BITS))
171 return hash_table + (s(i + index) & (HASH_SIZE - 1));
172 #undef i
173 #undef s
174 }
175
176 static struct metapage *search_hash(struct metapage ** hash_ptr,
177 struct address_space *mapping,
178 unsigned long index)
179 {
180 struct metapage *ptr;
181
182 for (ptr = *hash_ptr; ptr; ptr = ptr->hash_next) {
183 if ((ptr->mapping == mapping) && (ptr->index == index))
184 return ptr;
185 }
186
187 return NULL;
188 }
189
190 static void add_to_hash(struct metapage * mp, struct metapage ** hash_ptr)
191 {
192 if (*hash_ptr)
193 (*hash_ptr)->hash_prev = mp;
194
195 mp->hash_prev = NULL;
196 mp->hash_next = *hash_ptr;
197 *hash_ptr = mp;
198 }
199
200 static void remove_from_hash(struct metapage * mp, struct metapage ** hash_ptr)
201 {
202 if (mp->hash_prev)
203 mp->hash_prev->hash_next = mp->hash_next;
204 else {
205 assert(*hash_ptr == mp);
206 *hash_ptr = mp->hash_next;
207 }
208
209 if (mp->hash_next)
210 mp->hash_next->hash_prev = mp->hash_prev;
211 }
212
213 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
214 unsigned int size, int absolute,
215 unsigned long new)
216 {
217 struct metapage **hash_ptr;
218 int l2BlocksPerPage;
219 int l2bsize;
220 struct address_space *mapping;
221 struct metapage *mp;
222 unsigned long page_index;
223 unsigned long page_offset;
224
225 jfs_info("__get_metapage: inode = 0x%p, lblock = 0x%lx", inode, lblock);
226
227 if (absolute)
228 mapping = inode->i_sb->s_bdev->bd_inode->i_mapping;
229 else {
230 /*
231 * If an nfs client tries to read an inode that is larger
232 * than any existing inodes, we may try to read past the
233 * end of the inode map
234 */
235 if ((lblock << inode->i_blkbits) >= inode->i_size)
236 return NULL;
237 mapping = inode->i_mapping;
238 }
239
240 hash_ptr = meta_hash(mapping, lblock);
241 again:
242 spin_lock(&meta_lock);
243 mp = search_hash(hash_ptr, mapping, lblock);
244 if (mp) {
245 page_found:
246 if (test_bit(META_stale, &mp->flag)) {
247 spin_unlock(&meta_lock);
248 msleep(1);
249 goto again;
250 }
251 mp->count++;
252 lock_metapage(mp);
253 spin_unlock(&meta_lock);
254 if (test_bit(META_discard, &mp->flag)) {
255 if (!new) {
256 jfs_error(inode->i_sb,
257 "__get_metapage: using a "
258 "discarded metapage");
259 release_metapage(mp);
260 return NULL;
261 }
262 clear_bit(META_discard, &mp->flag);
263 }
264 jfs_info("__get_metapage: found 0x%p, in hash", mp);
265 if (mp->logical_size != size) {
266 jfs_error(inode->i_sb,
267 "__get_metapage: mp->logical_size != size");
268 release_metapage(mp);
269 return NULL;
270 }
271 } else {
272 l2bsize = inode->i_blkbits;
273 l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
274 page_index = lblock >> l2BlocksPerPage;
275 page_offset = (lblock - (page_index << l2BlocksPerPage)) <<
276 l2bsize;
277 if ((page_offset + size) > PAGE_CACHE_SIZE) {
278 spin_unlock(&meta_lock);
279 jfs_err("MetaData crosses page boundary!!");
280 return NULL;
281 }
282
283 /*
284 * Locks held on aggregate inode pages are usually
285 * not held long, and they are taken in critical code
286 * paths (committing dirty inodes, txCommit thread)
287 *
288 * Attempt to get metapage without blocking, tapping into
289 * reserves if necessary.
290 */
291 mp = NULL;
292 if (JFS_IP(inode)->fileset == AGGREGATE_I) {
293 mp = alloc_metapage(GFP_ATOMIC);
294 if (!mp) {
295 /*
296 * mempool is supposed to protect us from
297 * failing here. We will try a blocking
298 * call, but a deadlock is possible here
299 */
300 printk(KERN_WARNING
301 "__get_metapage: atomic call to mempool_alloc failed.\n");
302 printk(KERN_WARNING
303 "Will attempt blocking call\n");
304 }
305 }
306 if (!mp) {
307 struct metapage *mp2;
308
309 spin_unlock(&meta_lock);
310 mp = alloc_metapage(GFP_NOFS);
311 spin_lock(&meta_lock);
312
313 /* we dropped the meta_lock, we need to search the
314 * hash again.
315 */
316 mp2 = search_hash(hash_ptr, mapping, lblock);
317 if (mp2) {
318 free_metapage(mp);
319 mp = mp2;
320 goto page_found;
321 }
322 }
323 mp->flag = 0;
324 lock_metapage(mp);
325 if (absolute)
326 set_bit(META_absolute, &mp->flag);
327 mp->xflag = COMMIT_PAGE;
328 mp->count = 1;
329 atomic_set(&mp->nohomeok,0);
330 mp->mapping = mapping;
331 mp->index = lblock;
332 mp->page = NULL;
333 mp->logical_size = size;
334 add_to_hash(mp, hash_ptr);
335 spin_unlock(&meta_lock);
336
337 if (new) {
338 jfs_info("__get_metapage: Calling grab_cache_page");
339 mp->page = grab_cache_page(mapping, page_index);
340 if (!mp->page) {
341 jfs_err("grab_cache_page failed!");
342 goto freeit;
343 } else {
344 INCREMENT(mpStat.pagealloc);
345 unlock_page(mp->page);
346 }
347 } else {
348 jfs_info("__get_metapage: Calling read_cache_page");
349 mp->page = read_cache_page(mapping, lblock,
350 (filler_t *)mapping->a_ops->readpage, NULL);
351 if (IS_ERR(mp->page)) {
352 jfs_err("read_cache_page failed!");
353 goto freeit;
354 } else
355 INCREMENT(mpStat.pagealloc);
356 }
357 mp->data = kmap(mp->page) + page_offset;
358 }
359
360 if (new)
361 memset(mp->data, 0, PSIZE);
362
363 jfs_info("__get_metapage: returning = 0x%p", mp);
364 return mp;
365
366 freeit:
367 spin_lock(&meta_lock);
368 remove_from_hash(mp, hash_ptr);
369 free_metapage(mp);
370 spin_unlock(&meta_lock);
371 return NULL;
372 }
373
374 void hold_metapage(struct metapage * mp, int force)
375 {
376 spin_lock(&meta_lock);
377
378 mp->count++;
379
380 if (force) {
381 ASSERT (!(test_bit(META_forced, &mp->flag)));
382 if (trylock_metapage(mp))
383 set_bit(META_forced, &mp->flag);
384 } else
385 lock_metapage(mp);
386
387 spin_unlock(&meta_lock);
388 }
389
390 static void __write_metapage(struct metapage * mp)
391 {
392 int l2bsize = mp->mapping->host->i_blkbits;
393 int l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
394 unsigned long page_index;
395 unsigned long page_offset;
396 int rc;
397
398 jfs_info("__write_metapage: mp = 0x%p", mp);
399
400 page_index = mp->page->index;
401 page_offset =
402 (mp->index - (page_index << l2BlocksPerPage)) << l2bsize;
403
404 lock_page(mp->page);
405 rc = mp->mapping->a_ops->prepare_write(NULL, mp->page, page_offset,
406 page_offset +
407 mp->logical_size);
408 if (rc) {
409 jfs_err("prepare_write return %d!", rc);
410 ClearPageUptodate(mp->page);
411 unlock_page(mp->page);
412 clear_bit(META_dirty, &mp->flag);
413 return;
414 }
415 rc = mp->mapping->a_ops->commit_write(NULL, mp->page, page_offset,
416 page_offset +
417 mp->logical_size);
418 if (rc) {
419 jfs_err("commit_write returned %d", rc);
420 }
421
422 unlock_page(mp->page);
423 clear_bit(META_dirty, &mp->flag);
424
425 jfs_info("__write_metapage done");
426 }
427
428 static inline void sync_metapage(struct metapage *mp)
429 {
430 struct page *page = mp->page;
431
432 page_cache_get(page);
433 lock_page(page);
434
435 /* we're done with this page - no need to check for errors */
436 if (page_has_buffers(page))
437 write_one_page(page, 1);
438 else
439 unlock_page(page);
440 page_cache_release(page);
441 }
442
443 void release_metapage(struct metapage * mp)
444 {
445 struct jfs_log *log;
446
447 jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
448
449 spin_lock(&meta_lock);
450 if (test_bit(META_forced, &mp->flag)) {
451 clear_bit(META_forced, &mp->flag);
452 mp->count--;
453 spin_unlock(&meta_lock);
454 return;
455 }
456
457 assert(mp->count);
458 if (--mp->count || atomic_read(&mp->nohomeok)) {
459 unlock_metapage(mp);
460 spin_unlock(&meta_lock);
461 return;
462 }
463
464 if (mp->page) {
465 set_bit(META_stale, &mp->flag);
466 spin_unlock(&meta_lock);
467 kunmap(mp->page);
468 mp->data = NULL;
469 if (test_bit(META_dirty, &mp->flag))
470 __write_metapage(mp);
471 if (test_bit(META_sync, &mp->flag)) {
472 sync_metapage(mp);
473 clear_bit(META_sync, &mp->flag);
474 }
475
476 if (test_bit(META_discard, &mp->flag)) {
477 lock_page(mp->page);
478 block_invalidatepage(mp->page, 0);
479 unlock_page(mp->page);
480 }
481
482 page_cache_release(mp->page);
483 mp->page = NULL;
484 INCREMENT(mpStat.pagefree);
485 spin_lock(&meta_lock);
486 }
487
488 if (mp->lsn) {
489 /*
490 * Remove metapage from logsynclist.
491 */
492 log = mp->log;
493 LOGSYNC_LOCK(log);
494 mp->log = NULL;
495 mp->lsn = 0;
496 mp->clsn = 0;
497 log->count--;
498 list_del(&mp->synclist);
499 LOGSYNC_UNLOCK(log);
500 }
501 remove_from_hash(mp, meta_hash(mp->mapping, mp->index));
502 spin_unlock(&meta_lock);
503
504 free_metapage(mp);
505 }
506
507 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
508 {
509 struct metapage **hash_ptr;
510 unsigned long lblock;
511 int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
512 /* All callers are interested in block device's mapping */
513 struct address_space *mapping = ip->i_sb->s_bdev->bd_inode->i_mapping;
514 struct metapage *mp;
515 struct page *page;
516
517 /*
518 * First, mark metapages to discard. They will eventually be
519 * released, but should not be written.
520 */
521 for (lblock = addr; lblock < addr + len;
522 lblock += 1 << l2BlocksPerPage) {
523 hash_ptr = meta_hash(mapping, lblock);
524 again:
525 spin_lock(&meta_lock);
526 mp = search_hash(hash_ptr, mapping, lblock);
527 if (mp) {
528 if (test_bit(META_stale, &mp->flag)) {
529 spin_unlock(&meta_lock);
530 msleep(1);
531 goto again;
532 }
533
534 clear_bit(META_dirty, &mp->flag);
535 set_bit(META_discard, &mp->flag);
536 spin_unlock(&meta_lock);
537 } else {
538 spin_unlock(&meta_lock);
539 page = find_lock_page(mapping, lblock>>l2BlocksPerPage);
540 if (page) {
541 block_invalidatepage(page, 0);
542 unlock_page(page);
543 page_cache_release(page);
544 }
545 }
546 }
547 }
548
549 #ifdef CONFIG_JFS_STATISTICS
550 int jfs_mpstat_read(char *buffer, char **start, off_t offset, int length,
551 int *eof, void *data)
552 {
553 int len = 0;
554 off_t begin;
555
556 len += sprintf(buffer,
557 "JFS Metapage statistics\n"
558 "=======================\n"
559 "page allocations = %d\n"
560 "page frees = %d\n"
561 "lock waits = %d\n",
562 mpStat.pagealloc,
563 mpStat.pagefree,
564 mpStat.lockwait);
565
566 begin = offset;
567 *start = buffer + begin;
568 len -= begin;
569
570 if (len > length)
571 len = length;
572 else
573 *eof = 1;
574
575 if (len < 0)
576 len = 0;
577
578 return len;
579 }
580 #endif
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