]> git.proxmox.com Git - mirror_ubuntu-hirsute-kernel.git/blob - fs/fscache/page.c
projects / mirror_ubuntu-hirsute-kernel.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
sched: Remove proliferation of wait_on_bit() action functions
[mirror_ubuntu-hirsute-kernel.git] / fs / fscache / page.c
1 /* Cache page management and data I/O routines
2 *
3 * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12 #define FSCACHE_DEBUG_LEVEL PAGE
13 #include <linux/module.h>
14 #include <linux/fscache-cache.h>
15 #include <linux/buffer_head.h>
16 #include <linux/pagevec.h>
17 #include <linux/slab.h>
18 #include "internal.h"
19
20 /*
21 * check to see if a page is being written to the cache
22 */
23 bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page)
24 {
25 void *val;
26
27 rcu_read_lock();
28 val = radix_tree_lookup(&cookie->stores, page->index);
29 rcu_read_unlock();
30
31 return val != NULL;
32 }
33 EXPORT_SYMBOL(__fscache_check_page_write);
34
35 /*
36 * wait for a page to finish being written to the cache
37 */
38 void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page)
39 {
40 wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
41
42 wait_event(*wq, !__fscache_check_page_write(cookie, page));
43 }
44 EXPORT_SYMBOL(__fscache_wait_on_page_write);
45
46 /*
47 * decide whether a page can be released, possibly by cancelling a store to it
48 * - we're allowed to sleep if __GFP_WAIT is flagged
49 */
50 bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
51 struct page *page,
52 gfp_t gfp)
53 {
54 struct page *xpage;
55 void *val;
56
57 _enter("%p,%p,%x", cookie, page, gfp);
58
59 try_again:
60 rcu_read_lock();
61 val = radix_tree_lookup(&cookie->stores, page->index);
62 if (!val) {
63 rcu_read_unlock();
64 fscache_stat(&fscache_n_store_vmscan_not_storing);
65 __fscache_uncache_page(cookie, page);
66 return true;
67 }
68
69 /* see if the page is actually undergoing storage - if so we can't get
70 * rid of it till the cache has finished with it */
71 if (radix_tree_tag_get(&cookie->stores, page->index,
72 FSCACHE_COOKIE_STORING_TAG)) {
73 rcu_read_unlock();
74 goto page_busy;
75 }
76
77 /* the page is pending storage, so we attempt to cancel the store and
78 * discard the store request so that the page can be reclaimed */
79 spin_lock(&cookie->stores_lock);
80 rcu_read_unlock();
81
82 if (radix_tree_tag_get(&cookie->stores, page->index,
83 FSCACHE_COOKIE_STORING_TAG)) {
84 /* the page started to undergo storage whilst we were looking,
85 * so now we can only wait or return */
86 spin_unlock(&cookie->stores_lock);
87 goto page_busy;
88 }
89
90 xpage = radix_tree_delete(&cookie->stores, page->index);
91 spin_unlock(&cookie->stores_lock);
92
93 if (xpage) {
94 fscache_stat(&fscache_n_store_vmscan_cancelled);
95 fscache_stat(&fscache_n_store_radix_deletes);
96 ASSERTCMP(xpage, ==, page);
97 } else {
98 fscache_stat(&fscache_n_store_vmscan_gone);
99 }
100
101 wake_up_bit(&cookie->flags, 0);
102 if (xpage)
103 page_cache_release(xpage);
104 __fscache_uncache_page(cookie, page);
105 return true;
106
107 page_busy:
108 /* We will wait here if we're allowed to, but that could deadlock the
109 * allocator as the work threads writing to the cache may all end up
110 * sleeping on memory allocation, so we may need to impose a timeout
111 * too. */
112 if (!(gfp & __GFP_WAIT) || !(gfp & __GFP_FS)) {
113 fscache_stat(&fscache_n_store_vmscan_busy);
114 return false;
115 }
116
117 fscache_stat(&fscache_n_store_vmscan_wait);
118 __fscache_wait_on_page_write(cookie, page);
119 gfp &= ~__GFP_WAIT;
120 goto try_again;
121 }
122 EXPORT_SYMBOL(__fscache_maybe_release_page);
123
124 /*
125 * note that a page has finished being written to the cache
126 */
127 static void fscache_end_page_write(struct fscache_object *object,
128 struct page *page)
129 {
130 struct fscache_cookie *cookie;
131 struct page *xpage = NULL;
132
133 spin_lock(&object->lock);
134 cookie = object->cookie;
135 if (cookie) {
136 /* delete the page from the tree if it is now no longer
137 * pending */
138 spin_lock(&cookie->stores_lock);
139 radix_tree_tag_clear(&cookie->stores, page->index,
140 FSCACHE_COOKIE_STORING_TAG);
141 if (!radix_tree_tag_get(&cookie->stores, page->index,
142 FSCACHE_COOKIE_PENDING_TAG)) {
143 fscache_stat(&fscache_n_store_radix_deletes);
144 xpage = radix_tree_delete(&cookie->stores, page->index);
145 }
146 spin_unlock(&cookie->stores_lock);
147 wake_up_bit(&cookie->flags, 0);
148 }
149 spin_unlock(&object->lock);
150 if (xpage)
151 page_cache_release(xpage);
152 }
153
154 /*
155 * actually apply the changed attributes to a cache object
156 */
157 static void fscache_attr_changed_op(struct fscache_operation *op)
158 {
159 struct fscache_object *object = op->object;
160 int ret;
161
162 _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id);
163
164 fscache_stat(&fscache_n_attr_changed_calls);
165
166 if (fscache_object_is_active(object)) {
167 fscache_stat(&fscache_n_cop_attr_changed);
168 ret = object->cache->ops->attr_changed(object);
169 fscache_stat_d(&fscache_n_cop_attr_changed);
170 if (ret < 0)
171 fscache_abort_object(object);
172 }
173
174 fscache_op_complete(op, true);
175 _leave("");
176 }
177
178 /*
179 * notification that the attributes on an object have changed
180 */
181 int __fscache_attr_changed(struct fscache_cookie *cookie)
182 {
183 struct fscache_operation *op;
184 struct fscache_object *object;
185 bool wake_cookie;
186
187 _enter("%p", cookie);
188
189 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
190
191 fscache_stat(&fscache_n_attr_changed);
192
193 op = kzalloc(sizeof(*op), GFP_KERNEL);
194 if (!op) {
195 fscache_stat(&fscache_n_attr_changed_nomem);
196 _leave(" = -ENOMEM");
197 return -ENOMEM;
198 }
199
200 fscache_operation_init(op, fscache_attr_changed_op, NULL);
201 op->flags = FSCACHE_OP_ASYNC |
202 (1 << FSCACHE_OP_EXCLUSIVE) |
203 (1 << FSCACHE_OP_UNUSE_COOKIE);
204
205 spin_lock(&cookie->lock);
206
207 if (!fscache_cookie_enabled(cookie) ||
208 hlist_empty(&cookie->backing_objects))
209 goto nobufs;
210 object = hlist_entry(cookie->backing_objects.first,
211 struct fscache_object, cookie_link);
212
213 __fscache_use_cookie(cookie);
214 if (fscache_submit_exclusive_op(object, op) < 0)
215 goto nobufs;
216 spin_unlock(&cookie->lock);
217 fscache_stat(&fscache_n_attr_changed_ok);
218 fscache_put_operation(op);
219 _leave(" = 0");
220 return 0;
221
222 nobufs:
223 wake_cookie = __fscache_unuse_cookie(cookie);
224 spin_unlock(&cookie->lock);
225 kfree(op);
226 if (wake_cookie)
227 __fscache_wake_unused_cookie(cookie);
228 fscache_stat(&fscache_n_attr_changed_nobufs);
229 _leave(" = %d", -ENOBUFS);
230 return -ENOBUFS;
231 }
232 EXPORT_SYMBOL(__fscache_attr_changed);
233
234 /*
235 * release a retrieval op reference
236 */
237 static void fscache_release_retrieval_op(struct fscache_operation *_op)
238 {
239 struct fscache_retrieval *op =
240 container_of(_op, struct fscache_retrieval, op);
241
242 _enter("{OP%x}", op->op.debug_id);
243
244 ASSERTCMP(atomic_read(&op->n_pages), ==, 0);
245
246 fscache_hist(fscache_retrieval_histogram, op->start_time);
247 if (op->context)
248 fscache_put_context(op->op.object->cookie, op->context);
249
250 _leave("");
251 }
252
253 /*
254 * allocate a retrieval op
255 */
256 static struct fscache_retrieval *fscache_alloc_retrieval(
257 struct fscache_cookie *cookie,
258 struct address_space *mapping,
259 fscache_rw_complete_t end_io_func,
260 void *context)
261 {
262 struct fscache_retrieval *op;
263
264 /* allocate a retrieval operation and attempt to submit it */
265 op = kzalloc(sizeof(*op), GFP_NOIO);
266 if (!op) {
267 fscache_stat(&fscache_n_retrievals_nomem);
268 return NULL;
269 }
270
271 fscache_operation_init(&op->op, NULL, fscache_release_retrieval_op);
272 op->op.flags = FSCACHE_OP_MYTHREAD |
273 (1UL << FSCACHE_OP_WAITING) |
274 (1UL << FSCACHE_OP_UNUSE_COOKIE);
275 op->mapping = mapping;
276 op->end_io_func = end_io_func;
277 op->context = context;
278 op->start_time = jiffies;
279 INIT_LIST_HEAD(&op->to_do);
280 return op;
281 }
282
283 /*
284 * wait for a deferred lookup to complete
285 */
286 int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
287 {
288 unsigned long jif;
289
290 _enter("");
291
292 if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
293 _leave(" = 0 [imm]");
294 return 0;
295 }
296
297 fscache_stat(&fscache_n_retrievals_wait);
298
299 jif = jiffies;
300 if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
301 TASK_INTERRUPTIBLE) != 0) {
302 fscache_stat(&fscache_n_retrievals_intr);
303 _leave(" = -ERESTARTSYS");
304 return -ERESTARTSYS;
305 }
306
307 ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
308
309 smp_rmb();
310 fscache_hist(fscache_retrieval_delay_histogram, jif);
311 _leave(" = 0 [dly]");
312 return 0;
313 }
314
315 /*
316 * Handle cancellation of a pending retrieval op
317 */
318 static void fscache_do_cancel_retrieval(struct fscache_operation *_op)
319 {
320 struct fscache_retrieval *op =
321 container_of(_op, struct fscache_retrieval, op);
322
323 atomic_set(&op->n_pages, 0);
324 }
325
326 /*
327 * wait for an object to become active (or dead)
328 */
329 int fscache_wait_for_operation_activation(struct fscache_object *object,
330 struct fscache_operation *op,
331 atomic_t *stat_op_waits,
332 atomic_t *stat_object_dead,
333 void (*do_cancel)(struct fscache_operation *))
334 {
335 int ret;
336
337 if (!test_bit(FSCACHE_OP_WAITING, &op->flags))
338 goto check_if_dead;
339
340 _debug(">>> WT");
341 if (stat_op_waits)
342 fscache_stat(stat_op_waits);
343 if (wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
344 TASK_INTERRUPTIBLE) != 0) {
345 ret = fscache_cancel_op(op, do_cancel);
346 if (ret == 0)
347 return -ERESTARTSYS;
348
349 /* it's been removed from the pending queue by another party,
350 * so we should get to run shortly */
351 wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
352 TASK_UNINTERRUPTIBLE);
353 }
354 _debug("<<< GO");
355
356 check_if_dead:
357 if (op->state == FSCACHE_OP_ST_CANCELLED) {
358 if (stat_object_dead)
359 fscache_stat(stat_object_dead);
360 _leave(" = -ENOBUFS [cancelled]");
361 return -ENOBUFS;
362 }
363 if (unlikely(fscache_object_is_dead(object))) {
364 pr_err("%s() = -ENOBUFS [obj dead %d]\n", __func__, op->state);
365 fscache_cancel_op(op, do_cancel);
366 if (stat_object_dead)
367 fscache_stat(stat_object_dead);
368 return -ENOBUFS;
369 }
370 return 0;
371 }
372
373 /*
374 * read a page from the cache or allocate a block in which to store it
375 * - we return:
376 * -ENOMEM - out of memory, nothing done
377 * -ERESTARTSYS - interrupted
378 * -ENOBUFS - no backing object available in which to cache the block
379 * -ENODATA - no data available in the backing object for this block
380 * 0 - dispatched a read - it'll call end_io_func() when finished
381 */
382 int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
383 struct page *page,
384 fscache_rw_complete_t end_io_func,
385 void *context,
386 gfp_t gfp)
387 {
388 struct fscache_retrieval *op;
389 struct fscache_object *object;
390 bool wake_cookie = false;
391 int ret;
392
393 _enter("%p,%p,,,", cookie, page);
394
395 fscache_stat(&fscache_n_retrievals);
396
397 if (hlist_empty(&cookie->backing_objects))
398 goto nobufs;
399
400 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
401 _leave(" = -ENOBUFS [invalidating]");
402 return -ENOBUFS;
403 }
404
405 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
406 ASSERTCMP(page, !=, NULL);
407
408 if (fscache_wait_for_deferred_lookup(cookie) < 0)
409 return -ERESTARTSYS;
410
411 op = fscache_alloc_retrieval(cookie, page->mapping,
412 end_io_func, context);
413 if (!op) {
414 _leave(" = -ENOMEM");
415 return -ENOMEM;
416 }
417 atomic_set(&op->n_pages, 1);
418
419 spin_lock(&cookie->lock);
420
421 if (!fscache_cookie_enabled(cookie) ||
422 hlist_empty(&cookie->backing_objects))
423 goto nobufs_unlock;
424 object = hlist_entry(cookie->backing_objects.first,
425 struct fscache_object, cookie_link);
426
427 ASSERT(test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags));
428
429 __fscache_use_cookie(cookie);
430 atomic_inc(&object->n_reads);
431 __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
432
433 if (fscache_submit_op(object, &op->op) < 0)
434 goto nobufs_unlock_dec;
435 spin_unlock(&cookie->lock);
436
437 fscache_stat(&fscache_n_retrieval_ops);
438
439 /* pin the netfs read context in case we need to do the actual netfs
440 * read because we've encountered a cache read failure */
441 fscache_get_context(object->cookie, op->context);
442
443 /* we wait for the operation to become active, and then process it
444 * *here*, in this thread, and not in the thread pool */
445 ret = fscache_wait_for_operation_activation(
446 object, &op->op,
447 __fscache_stat(&fscache_n_retrieval_op_waits),
448 __fscache_stat(&fscache_n_retrievals_object_dead),
449 fscache_do_cancel_retrieval);
450 if (ret < 0)
451 goto error;
452
453 /* ask the cache to honour the operation */
454 if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
455 fscache_stat(&fscache_n_cop_allocate_page);
456 ret = object->cache->ops->allocate_page(op, page, gfp);
457 fscache_stat_d(&fscache_n_cop_allocate_page);
458 if (ret == 0)
459 ret = -ENODATA;
460 } else {
461 fscache_stat(&fscache_n_cop_read_or_alloc_page);
462 ret = object->cache->ops->read_or_alloc_page(op, page, gfp);
463 fscache_stat_d(&fscache_n_cop_read_or_alloc_page);
464 }
465
466 error:
467 if (ret == -ENOMEM)
468 fscache_stat(&fscache_n_retrievals_nomem);
469 else if (ret == -ERESTARTSYS)
470 fscache_stat(&fscache_n_retrievals_intr);
471 else if (ret == -ENODATA)
472 fscache_stat(&fscache_n_retrievals_nodata);
473 else if (ret < 0)
474 fscache_stat(&fscache_n_retrievals_nobufs);
475 else
476 fscache_stat(&fscache_n_retrievals_ok);
477
478 fscache_put_retrieval(op);
479 _leave(" = %d", ret);
480 return ret;
481
482 nobufs_unlock_dec:
483 atomic_dec(&object->n_reads);
484 wake_cookie = __fscache_unuse_cookie(cookie);
485 nobufs_unlock:
486 spin_unlock(&cookie->lock);
487 if (wake_cookie)
488 __fscache_wake_unused_cookie(cookie);
489 kfree(op);
490 nobufs:
491 fscache_stat(&fscache_n_retrievals_nobufs);
492 _leave(" = -ENOBUFS");
493 return -ENOBUFS;
494 }
495 EXPORT_SYMBOL(__fscache_read_or_alloc_page);
496
497 /*
498 * read a list of page from the cache or allocate a block in which to store
499 * them
500 * - we return:
501 * -ENOMEM - out of memory, some pages may be being read
502 * -ERESTARTSYS - interrupted, some pages may be being read
503 * -ENOBUFS - no backing object or space available in which to cache any
504 * pages not being read
505 * -ENODATA - no data available in the backing object for some or all of
506 * the pages
507 * 0 - dispatched a read on all pages
508 *
509 * end_io_func() will be called for each page read from the cache as it is
510 * finishes being read
511 *
512 * any pages for which a read is dispatched will be removed from pages and
513 * nr_pages
514 */
515 int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
516 struct address_space *mapping,
517 struct list_head *pages,
518 unsigned *nr_pages,
519 fscache_rw_complete_t end_io_func,
520 void *context,
521 gfp_t gfp)
522 {
523 struct fscache_retrieval *op;
524 struct fscache_object *object;
525 bool wake_cookie = false;
526 int ret;
527
528 _enter("%p,,%d,,,", cookie, *nr_pages);
529
530 fscache_stat(&fscache_n_retrievals);
531
532 if (hlist_empty(&cookie->backing_objects))
533 goto nobufs;
534
535 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
536 _leave(" = -ENOBUFS [invalidating]");
537 return -ENOBUFS;
538 }
539
540 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
541 ASSERTCMP(*nr_pages, >, 0);
542 ASSERT(!list_empty(pages));
543
544 if (fscache_wait_for_deferred_lookup(cookie) < 0)
545 return -ERESTARTSYS;
546
547 op = fscache_alloc_retrieval(cookie, mapping, end_io_func, context);
548 if (!op)
549 return -ENOMEM;
550 atomic_set(&op->n_pages, *nr_pages);
551
552 spin_lock(&cookie->lock);
553
554 if (!fscache_cookie_enabled(cookie) ||
555 hlist_empty(&cookie->backing_objects))
556 goto nobufs_unlock;
557 object = hlist_entry(cookie->backing_objects.first,
558 struct fscache_object, cookie_link);
559
560 __fscache_use_cookie(cookie);
561 atomic_inc(&object->n_reads);
562 __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
563
564 if (fscache_submit_op(object, &op->op) < 0)
565 goto nobufs_unlock_dec;
566 spin_unlock(&cookie->lock);
567
568 fscache_stat(&fscache_n_retrieval_ops);
569
570 /* pin the netfs read context in case we need to do the actual netfs
571 * read because we've encountered a cache read failure */
572 fscache_get_context(object->cookie, op->context);
573
574 /* we wait for the operation to become active, and then process it
575 * *here*, in this thread, and not in the thread pool */
576 ret = fscache_wait_for_operation_activation(
577 object, &op->op,
578 __fscache_stat(&fscache_n_retrieval_op_waits),
579 __fscache_stat(&fscache_n_retrievals_object_dead),
580 fscache_do_cancel_retrieval);
581 if (ret < 0)
582 goto error;
583
584 /* ask the cache to honour the operation */
585 if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
586 fscache_stat(&fscache_n_cop_allocate_pages);
587 ret = object->cache->ops->allocate_pages(
588 op, pages, nr_pages, gfp);
589 fscache_stat_d(&fscache_n_cop_allocate_pages);
590 } else {
591 fscache_stat(&fscache_n_cop_read_or_alloc_pages);
592 ret = object->cache->ops->read_or_alloc_pages(
593 op, pages, nr_pages, gfp);
594 fscache_stat_d(&fscache_n_cop_read_or_alloc_pages);
595 }
596
597 error:
598 if (ret == -ENOMEM)
599 fscache_stat(&fscache_n_retrievals_nomem);
600 else if (ret == -ERESTARTSYS)
601 fscache_stat(&fscache_n_retrievals_intr);
602 else if (ret == -ENODATA)
603 fscache_stat(&fscache_n_retrievals_nodata);
604 else if (ret < 0)
605 fscache_stat(&fscache_n_retrievals_nobufs);
606 else
607 fscache_stat(&fscache_n_retrievals_ok);
608
609 fscache_put_retrieval(op);
610 _leave(" = %d", ret);
611 return ret;
612
613 nobufs_unlock_dec:
614 atomic_dec(&object->n_reads);
615 wake_cookie = __fscache_unuse_cookie(cookie);
616 nobufs_unlock:
617 spin_unlock(&cookie->lock);
618 kfree(op);
619 if (wake_cookie)
620 __fscache_wake_unused_cookie(cookie);
621 nobufs:
622 fscache_stat(&fscache_n_retrievals_nobufs);
623 _leave(" = -ENOBUFS");
624 return -ENOBUFS;
625 }
626 EXPORT_SYMBOL(__fscache_read_or_alloc_pages);
627
628 /*
629 * allocate a block in the cache on which to store a page
630 * - we return:
631 * -ENOMEM - out of memory, nothing done
632 * -ERESTARTSYS - interrupted
633 * -ENOBUFS - no backing object available in which to cache the block
634 * 0 - block allocated
635 */
636 int __fscache_alloc_page(struct fscache_cookie *cookie,
637 struct page *page,
638 gfp_t gfp)
639 {
640 struct fscache_retrieval *op;
641 struct fscache_object *object;
642 bool wake_cookie = false;
643 int ret;
644
645 _enter("%p,%p,,,", cookie, page);
646
647 fscache_stat(&fscache_n_allocs);
648
649 if (hlist_empty(&cookie->backing_objects))
650 goto nobufs;
651
652 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
653 ASSERTCMP(page, !=, NULL);
654
655 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
656 _leave(" = -ENOBUFS [invalidating]");
657 return -ENOBUFS;
658 }
659
660 if (fscache_wait_for_deferred_lookup(cookie) < 0)
661 return -ERESTARTSYS;
662
663 op = fscache_alloc_retrieval(cookie, page->mapping, NULL, NULL);
664 if (!op)
665 return -ENOMEM;
666 atomic_set(&op->n_pages, 1);
667
668 spin_lock(&cookie->lock);
669
670 if (!fscache_cookie_enabled(cookie) ||
671 hlist_empty(&cookie->backing_objects))
672 goto nobufs_unlock;
673 object = hlist_entry(cookie->backing_objects.first,
674 struct fscache_object, cookie_link);
675
676 __fscache_use_cookie(cookie);
677 if (fscache_submit_op(object, &op->op) < 0)
678 goto nobufs_unlock_dec;
679 spin_unlock(&cookie->lock);
680
681 fscache_stat(&fscache_n_alloc_ops);
682
683 ret = fscache_wait_for_operation_activation(
684 object, &op->op,
685 __fscache_stat(&fscache_n_alloc_op_waits),
686 __fscache_stat(&fscache_n_allocs_object_dead),
687 fscache_do_cancel_retrieval);
688 if (ret < 0)
689 goto error;
690
691 /* ask the cache to honour the operation */
692 fscache_stat(&fscache_n_cop_allocate_page);
693 ret = object->cache->ops->allocate_page(op, page, gfp);
694 fscache_stat_d(&fscache_n_cop_allocate_page);
695
696 error:
697 if (ret == -ERESTARTSYS)
698 fscache_stat(&fscache_n_allocs_intr);
699 else if (ret < 0)
700 fscache_stat(&fscache_n_allocs_nobufs);
701 else
702 fscache_stat(&fscache_n_allocs_ok);
703
704 fscache_put_retrieval(op);
705 _leave(" = %d", ret);
706 return ret;
707
708 nobufs_unlock_dec:
709 wake_cookie = __fscache_unuse_cookie(cookie);
710 nobufs_unlock:
711 spin_unlock(&cookie->lock);
712 kfree(op);
713 if (wake_cookie)
714 __fscache_wake_unused_cookie(cookie);
715 nobufs:
716 fscache_stat(&fscache_n_allocs_nobufs);
717 _leave(" = -ENOBUFS");
718 return -ENOBUFS;
719 }
720 EXPORT_SYMBOL(__fscache_alloc_page);
721
722 /*
723 * Unmark pages allocate in the readahead code path (via:
724 * fscache_readpages_or_alloc) after delegating to the base filesystem
725 */
726 void __fscache_readpages_cancel(struct fscache_cookie *cookie,
727 struct list_head *pages)
728 {
729 struct page *page;
730
731 list_for_each_entry(page, pages, lru) {
732 if (PageFsCache(page))
733 __fscache_uncache_page(cookie, page);
734 }
735 }
736 EXPORT_SYMBOL(__fscache_readpages_cancel);
737
738 /*
739 * release a write op reference
740 */
741 static void fscache_release_write_op(struct fscache_operation *_op)
742 {
743 _enter("{OP%x}", _op->debug_id);
744 }
745
746 /*
747 * perform the background storage of a page into the cache
748 */
749 static void fscache_write_op(struct fscache_operation *_op)
750 {
751 struct fscache_storage *op =
752 container_of(_op, struct fscache_storage, op);
753 struct fscache_object *object = op->op.object;
754 struct fscache_cookie *cookie;
755 struct page *page;
756 unsigned n;
757 void *results[1];
758 int ret;
759
760 _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage));
761
762 spin_lock(&object->lock);
763 cookie = object->cookie;
764
765 if (!fscache_object_is_active(object)) {
766 /* If we get here, then the on-disk cache object likely longer
767 * exists, so we should just cancel this write operation.
768 */
769 spin_unlock(&object->lock);
770 fscache_op_complete(&op->op, false);
771 _leave(" [inactive]");
772 return;
773 }
774
775 if (!cookie) {
776 /* If we get here, then the cookie belonging to the object was
777 * detached, probably by the cookie being withdrawn due to
778 * memory pressure, which means that the pages we might write
779 * to the cache from no longer exist - therefore, we can just
780 * cancel this write operation.
781 */
782 spin_unlock(&object->lock);
783 fscache_op_complete(&op->op, false);
784 _leave(" [cancel] op{f=%lx s=%u} obj{s=%s f=%lx}",
785 _op->flags, _op->state, object->state->short_name,
786 object->flags);
787 return;
788 }
789
790 spin_lock(&cookie->stores_lock);
791
792 fscache_stat(&fscache_n_store_calls);
793
794 /* find a page to store */
795 page = NULL;
796 n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
797 FSCACHE_COOKIE_PENDING_TAG);
798 if (n != 1)
799 goto superseded;
800 page = results[0];
801 _debug("gang %d [%lx]", n, page->index);
802 if (page->index > op->store_limit) {
803 fscache_stat(&fscache_n_store_pages_over_limit);
804 goto superseded;
805 }
806
807 radix_tree_tag_set(&cookie->stores, page->index,
808 FSCACHE_COOKIE_STORING_TAG);
809 radix_tree_tag_clear(&cookie->stores, page->index,
810 FSCACHE_COOKIE_PENDING_TAG);
811
812 spin_unlock(&cookie->stores_lock);
813 spin_unlock(&object->lock);
814
815 fscache_stat(&fscache_n_store_pages);
816 fscache_stat(&fscache_n_cop_write_page);
817 ret = object->cache->ops->write_page(op, page);
818 fscache_stat_d(&fscache_n_cop_write_page);
819 fscache_end_page_write(object, page);
820 if (ret < 0) {
821 fscache_abort_object(object);
822 fscache_op_complete(&op->op, true);
823 } else {
824 fscache_enqueue_operation(&op->op);
825 }
826
827 _leave("");
828 return;
829
830 superseded:
831 /* this writer is going away and there aren't any more things to
832 * write */
833 _debug("cease");
834 spin_unlock(&cookie->stores_lock);
835 clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
836 spin_unlock(&object->lock);
837 fscache_op_complete(&op->op, true);
838 _leave("");
839 }
840
841 /*
842 * Clear the pages pending writing for invalidation
843 */
844 void fscache_invalidate_writes(struct fscache_cookie *cookie)
845 {
846 struct page *page;
847 void *results[16];
848 int n, i;
849
850 _enter("");
851
852 for (;;) {
853 spin_lock(&cookie->stores_lock);
854 n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
855 ARRAY_SIZE(results),
856 FSCACHE_COOKIE_PENDING_TAG);
857 if (n == 0) {
858 spin_unlock(&cookie->stores_lock);
859 break;
860 }
861
862 for (i = n - 1; i >= 0; i--) {
863 page = results[i];
864 radix_tree_delete(&cookie->stores, page->index);
865 }
866
867 spin_unlock(&cookie->stores_lock);
868
869 for (i = n - 1; i >= 0; i--)
870 page_cache_release(results[i]);
871 }
872
873 _leave("");
874 }
875
876 /*
877 * request a page be stored in the cache
878 * - returns:
879 * -ENOMEM - out of memory, nothing done
880 * -ENOBUFS - no backing object available in which to cache the page
881 * 0 - dispatched a write - it'll call end_io_func() when finished
882 *
883 * if the cookie still has a backing object at this point, that object can be
884 * in one of a few states with respect to storage processing:
885 *
886 * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is
887 * set)
888 *
889 * (a) no writes yet
890 *
891 * (b) writes deferred till post-creation (mark page for writing and
892 * return immediately)
893 *
894 * (2) negative lookup, object created, initial fill being made from netfs
895 *
896 * (a) fill point not yet reached this page (mark page for writing and
897 * return)
898 *
899 * (b) fill point passed this page (queue op to store this page)
900 *
901 * (3) object extant (queue op to store this page)
902 *
903 * any other state is invalid
904 */
905 int __fscache_write_page(struct fscache_cookie *cookie,
906 struct page *page,
907 gfp_t gfp)
908 {
909 struct fscache_storage *op;
910 struct fscache_object *object;
911 bool wake_cookie = false;
912 int ret;
913
914 _enter("%p,%x,", cookie, (u32) page->flags);
915
916 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
917 ASSERT(PageFsCache(page));
918
919 fscache_stat(&fscache_n_stores);
920
921 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
922 _leave(" = -ENOBUFS [invalidating]");
923 return -ENOBUFS;
924 }
925
926 op = kzalloc(sizeof(*op), GFP_NOIO | __GFP_NOMEMALLOC | __GFP_NORETRY);
927 if (!op)
928 goto nomem;
929
930 fscache_operation_init(&op->op, fscache_write_op,
931 fscache_release_write_op);
932 op->op.flags = FSCACHE_OP_ASYNC |
933 (1 << FSCACHE_OP_WAITING) |
934 (1 << FSCACHE_OP_UNUSE_COOKIE);
935
936 ret = radix_tree_maybe_preload(gfp & ~__GFP_HIGHMEM);
937 if (ret < 0)
938 goto nomem_free;
939
940 ret = -ENOBUFS;
941 spin_lock(&cookie->lock);
942
943 if (!fscache_cookie_enabled(cookie) ||
944 hlist_empty(&cookie->backing_objects))
945 goto nobufs;
946 object = hlist_entry(cookie->backing_objects.first,
947 struct fscache_object, cookie_link);
948 if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
949 goto nobufs;
950
951 /* add the page to the pending-storage radix tree on the backing
952 * object */
953 spin_lock(&object->lock);
954 spin_lock(&cookie->stores_lock);
955
956 _debug("store limit %llx", (unsigned long long) object->store_limit);
957
958 ret = radix_tree_insert(&cookie->stores, page->index, page);
959 if (ret < 0) {
960 if (ret == -EEXIST)
961 goto already_queued;
962 _debug("insert failed %d", ret);
963 goto nobufs_unlock_obj;
964 }
965
966 radix_tree_tag_set(&cookie->stores, page->index,
967 FSCACHE_COOKIE_PENDING_TAG);
968 page_cache_get(page);
969
970 /* we only want one writer at a time, but we do need to queue new
971 * writers after exclusive ops */
972 if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags))
973 goto already_pending;
974
975 spin_unlock(&cookie->stores_lock);
976 spin_unlock(&object->lock);
977
978 op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
979 op->store_limit = object->store_limit;
980
981 __fscache_use_cookie(cookie);
982 if (fscache_submit_op(object, &op->op) < 0)
983 goto submit_failed;
984
985 spin_unlock(&cookie->lock);
986 radix_tree_preload_end();
987 fscache_stat(&fscache_n_store_ops);
988 fscache_stat(&fscache_n_stores_ok);
989
990 /* the work queue now carries its own ref on the object */
991 fscache_put_operation(&op->op);
992 _leave(" = 0");
993 return 0;
994
995 already_queued:
996 fscache_stat(&fscache_n_stores_again);
997 already_pending:
998 spin_unlock(&cookie->stores_lock);
999 spin_unlock(&object->lock);
1000 spin_unlock(&cookie->lock);
1001 radix_tree_preload_end();
1002 kfree(op);
1003 fscache_stat(&fscache_n_stores_ok);
1004 _leave(" = 0");
1005 return 0;
1006
1007 submit_failed:
1008 spin_lock(&cookie->stores_lock);
1009 radix_tree_delete(&cookie->stores, page->index);
1010 spin_unlock(&cookie->stores_lock);
1011 wake_cookie = __fscache_unuse_cookie(cookie);
1012 page_cache_release(page);
1013 ret = -ENOBUFS;
1014 goto nobufs;
1015
1016 nobufs_unlock_obj:
1017 spin_unlock(&cookie->stores_lock);
1018 spin_unlock(&object->lock);
1019 nobufs:
1020 spin_unlock(&cookie->lock);
1021 radix_tree_preload_end();
1022 kfree(op);
1023 if (wake_cookie)
1024 __fscache_wake_unused_cookie(cookie);
1025 fscache_stat(&fscache_n_stores_nobufs);
1026 _leave(" = -ENOBUFS");
1027 return -ENOBUFS;
1028
1029 nomem_free:
1030 kfree(op);
1031 nomem:
1032 fscache_stat(&fscache_n_stores_oom);
1033 _leave(" = -ENOMEM");
1034 return -ENOMEM;
1035 }
1036 EXPORT_SYMBOL(__fscache_write_page);
1037
1038 /*
1039 * remove a page from the cache
1040 */
1041 void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page)
1042 {
1043 struct fscache_object *object;
1044
1045 _enter(",%p", page);
1046
1047 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
1048 ASSERTCMP(page, !=, NULL);
1049
1050 fscache_stat(&fscache_n_uncaches);
1051
1052 /* cache withdrawal may beat us to it */
1053 if (!PageFsCache(page))
1054 goto done;
1055
1056 /* get the object */
1057 spin_lock(&cookie->lock);
1058
1059 if (hlist_empty(&cookie->backing_objects)) {
1060 ClearPageFsCache(page);
1061 goto done_unlock;
1062 }
1063
1064 object = hlist_entry(cookie->backing_objects.first,
1065 struct fscache_object, cookie_link);
1066
1067 /* there might now be stuff on disk we could read */
1068 clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
1069
1070 /* only invoke the cache backend if we managed to mark the page
1071 * uncached here; this deals with synchronisation vs withdrawal */
1072 if (TestClearPageFsCache(page) &&
1073 object->cache->ops->uncache_page) {
1074 /* the cache backend releases the cookie lock */
1075 fscache_stat(&fscache_n_cop_uncache_page);
1076 object->cache->ops->uncache_page(object, page);
1077 fscache_stat_d(&fscache_n_cop_uncache_page);
1078 goto done;
1079 }
1080
1081 done_unlock:
1082 spin_unlock(&cookie->lock);
1083 done:
1084 _leave("");
1085 }
1086 EXPORT_SYMBOL(__fscache_uncache_page);
1087
1088 /**
1089 * fscache_mark_page_cached - Mark a page as being cached
1090 * @op: The retrieval op pages are being marked for
1091 * @page: The page to be marked
1092 *
1093 * Mark a netfs page as being cached. After this is called, the netfs
1094 * must call fscache_uncache_page() to remove the mark.
1095 */
1096 void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page)
1097 {
1098 struct fscache_cookie *cookie = op->op.object->cookie;
1099
1100 #ifdef CONFIG_FSCACHE_STATS
1101 atomic_inc(&fscache_n_marks);
1102 #endif
1103
1104 _debug("- mark %p{%lx}", page, page->index);
1105 if (TestSetPageFsCache(page)) {
1106 static bool once_only;
1107 if (!once_only) {
1108 once_only = true;
1109 pr_warn("Cookie type %s marked page %lx multiple times\n",
1110 cookie->def->name, page->index);
1111 }
1112 }
1113
1114 if (cookie->def->mark_page_cached)
1115 cookie->def->mark_page_cached(cookie->netfs_data,
1116 op->mapping, page);
1117 }
1118 EXPORT_SYMBOL(fscache_mark_page_cached);
1119
1120 /**
1121 * fscache_mark_pages_cached - Mark pages as being cached
1122 * @op: The retrieval op pages are being marked for
1123 * @pagevec: The pages to be marked
1124 *
1125 * Mark a bunch of netfs pages as being cached. After this is called,
1126 * the netfs must call fscache_uncache_page() to remove the mark.
1127 */
1128 void fscache_mark_pages_cached(struct fscache_retrieval *op,
1129 struct pagevec *pagevec)
1130 {
1131 unsigned long loop;
1132
1133 for (loop = 0; loop < pagevec->nr; loop++)
1134 fscache_mark_page_cached(op, pagevec->pages[loop]);
1135
1136 pagevec_reinit(pagevec);
1137 }
1138 EXPORT_SYMBOL(fscache_mark_pages_cached);
1139
1140 /*
1141 * Uncache all the pages in an inode that are marked PG_fscache, assuming them
1142 * to be associated with the given cookie.
1143 */
1144 void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
1145 struct inode *inode)
1146 {
1147 struct address_space *mapping = inode->i_mapping;
1148 struct pagevec pvec;
1149 pgoff_t next;
1150 int i;
1151
1152 _enter("%p,%p", cookie, inode);
1153
1154 if (!mapping || mapping->nrpages == 0) {
1155 _leave(" [no pages]");
1156 return;
1157 }
1158
1159 pagevec_init(&pvec, 0);
1160 next = 0;
1161 do {
1162 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
1163 break;
1164 for (i = 0; i < pagevec_count(&pvec); i++) {
1165 struct page *page = pvec.pages[i];
1166 next = page->index;
1167 if (PageFsCache(page)) {
1168 __fscache_wait_on_page_write(cookie, page);
1169 __fscache_uncache_page(cookie, page);
1170 }
1171 }
1172 pagevec_release(&pvec);
1173 cond_resched();
1174 } while (++next);
1175
1176 _leave("");
1177 }
1178 EXPORT_SYMBOL(__fscache_uncache_all_inode_pages);
Ubuntu Hirsute Linux kernel mirror