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x86/amd-iommu: Add per IOMMU reference counting
[linux/fpc-iii.git] / fs / fscache / page.c
blob2568e0eb644f67453d2acca6e3aac584a513ea2c
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 "internal.h"
18
19 /*
20 * check to see if a page is being written to the cache
21 */
22 bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page)
23 {
24 void *val;
25
26 rcu_read_lock();
27 val = radix_tree_lookup(&cookie->stores, page->index);
28 rcu_read_unlock();
29
30 return val != NULL;
31 }
32 EXPORT_SYMBOL(__fscache_check_page_write);
33
34 /*
35 * wait for a page to finish being written to the cache
36 */
37 void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page)
38 {
39 wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
40
41 wait_event(*wq, !__fscache_check_page_write(cookie, page));
42 }
43 EXPORT_SYMBOL(__fscache_wait_on_page_write);
44
45 /*
46 * note that a page has finished being written to the cache
47 */
48 static void fscache_end_page_write(struct fscache_cookie *cookie, struct page *page)
49 {
50 struct page *xpage;
51
52 spin_lock(&cookie->lock);
53 xpage = radix_tree_delete(&cookie->stores, page->index);
54 spin_unlock(&cookie->lock);
55 ASSERT(xpage != NULL);
56
57 wake_up_bit(&cookie->flags, 0);
58 }
59
60 /*
61 * actually apply the changed attributes to a cache object
62 */
63 static void fscache_attr_changed_op(struct fscache_operation *op)
64 {
65 struct fscache_object *object = op->object;
66
67 _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id);
68
69 fscache_stat(&fscache_n_attr_changed_calls);
70
71 if (fscache_object_is_active(object) &&
72 object->cache->ops->attr_changed(object) < 0)
73 fscache_abort_object(object);
74
75 _leave("");
76 }
77
78 /*
79 * notification that the attributes on an object have changed
80 */
81 int __fscache_attr_changed(struct fscache_cookie *cookie)
82 {
83 struct fscache_operation *op;
84 struct fscache_object *object;
85
86 _enter("%p", cookie);
87
88 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
89
90 fscache_stat(&fscache_n_attr_changed);
91
92 op = kzalloc(sizeof(*op), GFP_KERNEL);
93 if (!op) {
94 fscache_stat(&fscache_n_attr_changed_nomem);
95 _leave(" = -ENOMEM");
96 return -ENOMEM;
97 }
98
99 fscache_operation_init(op, NULL);
100 fscache_operation_init_slow(op, fscache_attr_changed_op);
101 op->flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_EXCLUSIVE);
102
103 spin_lock(&cookie->lock);
104
105 if (hlist_empty(&cookie->backing_objects))
106 goto nobufs;
107 object = hlist_entry(cookie->backing_objects.first,
108 struct fscache_object, cookie_link);
109
110 if (fscache_submit_exclusive_op(object, op) < 0)
111 goto nobufs;
112 spin_unlock(&cookie->lock);
113 fscache_stat(&fscache_n_attr_changed_ok);
114 fscache_put_operation(op);
115 _leave(" = 0");
116 return 0;
117
118 nobufs:
119 spin_unlock(&cookie->lock);
120 kfree(op);
121 fscache_stat(&fscache_n_attr_changed_nobufs);
122 _leave(" = %d", -ENOBUFS);
123 return -ENOBUFS;
124 }
125 EXPORT_SYMBOL(__fscache_attr_changed);
126
127 /*
128 * handle secondary execution given to a retrieval op on behalf of the
129 * cache
130 */
131 static void fscache_retrieval_work(struct work_struct *work)
132 {
133 struct fscache_retrieval *op =
134 container_of(work, struct fscache_retrieval, op.fast_work);
135 unsigned long start;
136
137 _enter("{OP%x}", op->op.debug_id);
138
139 start = jiffies;
140 op->op.processor(&op->op);
141 fscache_hist(fscache_ops_histogram, start);
142 fscache_put_operation(&op->op);
143 }
144
145 /*
146 * release a retrieval op reference
147 */
148 static void fscache_release_retrieval_op(struct fscache_operation *_op)
149 {
150 struct fscache_retrieval *op =
151 container_of(_op, struct fscache_retrieval, op);
152
153 _enter("{OP%x}", op->op.debug_id);
154
155 fscache_hist(fscache_retrieval_histogram, op->start_time);
156 if (op->context)
157 fscache_put_context(op->op.object->cookie, op->context);
158
159 _leave("");
160 }
161
162 /*
163 * allocate a retrieval op
164 */
165 static struct fscache_retrieval *fscache_alloc_retrieval(
166 struct address_space *mapping,
167 fscache_rw_complete_t end_io_func,
168 void *context)
169 {
170 struct fscache_retrieval *op;
171
172 /* allocate a retrieval operation and attempt to submit it */
173 op = kzalloc(sizeof(*op), GFP_NOIO);
174 if (!op) {
175 fscache_stat(&fscache_n_retrievals_nomem);
176 return NULL;
177 }
178
179 fscache_operation_init(&op->op, fscache_release_retrieval_op);
180 op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING);
181 op->mapping = mapping;
182 op->end_io_func = end_io_func;
183 op->context = context;
184 op->start_time = jiffies;
185 INIT_WORK(&op->op.fast_work, fscache_retrieval_work);
186 INIT_LIST_HEAD(&op->to_do);
187 return op;
188 }
189
190 /*
191 * wait for a deferred lookup to complete
192 */
193 static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
194 {
195 unsigned long jif;
196
197 _enter("");
198
199 if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
200 _leave(" = 0 [imm]");
201 return 0;
202 }
203
204 fscache_stat(&fscache_n_retrievals_wait);
205
206 jif = jiffies;
207 if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
208 fscache_wait_bit_interruptible,
209 TASK_INTERRUPTIBLE) != 0) {
210 fscache_stat(&fscache_n_retrievals_intr);
211 _leave(" = -ERESTARTSYS");
212 return -ERESTARTSYS;
213 }
214
215 ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
216
217 smp_rmb();
218 fscache_hist(fscache_retrieval_delay_histogram, jif);
219 _leave(" = 0 [dly]");
220 return 0;
221 }
222
223 /*
224 * read a page from the cache or allocate a block in which to store it
225 * - we return:
226 * -ENOMEM - out of memory, nothing done
227 * -ERESTARTSYS - interrupted
228 * -ENOBUFS - no backing object available in which to cache the block
229 * -ENODATA - no data available in the backing object for this block
230 * 0 - dispatched a read - it'll call end_io_func() when finished
231 */
232 int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
233 struct page *page,
234 fscache_rw_complete_t end_io_func,
235 void *context,
236 gfp_t gfp)
237 {
238 struct fscache_retrieval *op;
239 struct fscache_object *object;
240 int ret;
241
242 _enter("%p,%p,,,", cookie, page);
243
244 fscache_stat(&fscache_n_retrievals);
245
246 if (hlist_empty(&cookie->backing_objects))
247 goto nobufs;
248
249 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
250 ASSERTCMP(page, !=, NULL);
251
252 if (fscache_wait_for_deferred_lookup(cookie) < 0)
253 return -ERESTARTSYS;
254
255 op = fscache_alloc_retrieval(page->mapping, end_io_func, context);
256 if (!op) {
257 _leave(" = -ENOMEM");
258 return -ENOMEM;
259 }
260
261 spin_lock(&cookie->lock);
262
263 if (hlist_empty(&cookie->backing_objects))
264 goto nobufs_unlock;
265 object = hlist_entry(cookie->backing_objects.first,
266 struct fscache_object, cookie_link);
267
268 ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP);
269
270 if (fscache_submit_op(object, &op->op) < 0)
271 goto nobufs_unlock;
272 spin_unlock(&cookie->lock);
273
274 fscache_stat(&fscache_n_retrieval_ops);
275
276 /* pin the netfs read context in case we need to do the actual netfs
277 * read because we've encountered a cache read failure */
278 fscache_get_context(object->cookie, op->context);
279
280 /* we wait for the operation to become active, and then process it
281 * *here*, in this thread, and not in the thread pool */
282 if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
283 _debug(">>> WT");
284 fscache_stat(&fscache_n_retrieval_op_waits);
285 wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
286 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
287 _debug("<<< GO");
288 }
289
290 /* ask the cache to honour the operation */
291 if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
292 ret = object->cache->ops->allocate_page(op, page, gfp);
293 if (ret == 0)
294 ret = -ENODATA;
295 } else {
296 ret = object->cache->ops->read_or_alloc_page(op, page, gfp);
297 }
298
299 if (ret == -ENOMEM)
300 fscache_stat(&fscache_n_retrievals_nomem);
301 else if (ret == -ERESTARTSYS)
302 fscache_stat(&fscache_n_retrievals_intr);
303 else if (ret == -ENODATA)
304 fscache_stat(&fscache_n_retrievals_nodata);
305 else if (ret < 0)
306 fscache_stat(&fscache_n_retrievals_nobufs);
307 else
308 fscache_stat(&fscache_n_retrievals_ok);
309
310 fscache_put_retrieval(op);
311 _leave(" = %d", ret);
312 return ret;
313
314 nobufs_unlock:
315 spin_unlock(&cookie->lock);
316 kfree(op);
317 nobufs:
318 fscache_stat(&fscache_n_retrievals_nobufs);
319 _leave(" = -ENOBUFS");
320 return -ENOBUFS;
321 }
322 EXPORT_SYMBOL(__fscache_read_or_alloc_page);
323
324 /*
325 * read a list of page from the cache or allocate a block in which to store
326 * them
327 * - we return:
328 * -ENOMEM - out of memory, some pages may be being read
329 * -ERESTARTSYS - interrupted, some pages may be being read
330 * -ENOBUFS - no backing object or space available in which to cache any
331 * pages not being read
332 * -ENODATA - no data available in the backing object for some or all of
333 * the pages
334 * 0 - dispatched a read on all pages
335 *
336 * end_io_func() will be called for each page read from the cache as it is
337 * finishes being read
338 *
339 * any pages for which a read is dispatched will be removed from pages and
340 * nr_pages
341 */
342 int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
343 struct address_space *mapping,
344 struct list_head *pages,
345 unsigned *nr_pages,
346 fscache_rw_complete_t end_io_func,
347 void *context,
348 gfp_t gfp)
349 {
350 fscache_pages_retrieval_func_t func;
351 struct fscache_retrieval *op;
352 struct fscache_object *object;
353 int ret;
354
355 _enter("%p,,%d,,,", cookie, *nr_pages);
356
357 fscache_stat(&fscache_n_retrievals);
358
359 if (hlist_empty(&cookie->backing_objects))
360 goto nobufs;
361
362 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
363 ASSERTCMP(*nr_pages, >, 0);
364 ASSERT(!list_empty(pages));
365
366 if (fscache_wait_for_deferred_lookup(cookie) < 0)
367 return -ERESTARTSYS;
368
369 op = fscache_alloc_retrieval(mapping, end_io_func, context);
370 if (!op)
371 return -ENOMEM;
372
373 spin_lock(&cookie->lock);
374
375 if (hlist_empty(&cookie->backing_objects))
376 goto nobufs_unlock;
377 object = hlist_entry(cookie->backing_objects.first,
378 struct fscache_object, cookie_link);
379
380 if (fscache_submit_op(object, &op->op) < 0)
381 goto nobufs_unlock;
382 spin_unlock(&cookie->lock);
383
384 fscache_stat(&fscache_n_retrieval_ops);
385
386 /* pin the netfs read context in case we need to do the actual netfs
387 * read because we've encountered a cache read failure */
388 fscache_get_context(object->cookie, op->context);
389
390 /* we wait for the operation to become active, and then process it
391 * *here*, in this thread, and not in the thread pool */
392 if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
393 _debug(">>> WT");
394 fscache_stat(&fscache_n_retrieval_op_waits);
395 wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
396 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
397 _debug("<<< GO");
398 }
399
400 /* ask the cache to honour the operation */
401 if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags))
402 func = object->cache->ops->allocate_pages;
403 else
404 func = object->cache->ops->read_or_alloc_pages;
405 ret = func(op, pages, nr_pages, gfp);
406
407 if (ret == -ENOMEM)
408 fscache_stat(&fscache_n_retrievals_nomem);
409 else if (ret == -ERESTARTSYS)
410 fscache_stat(&fscache_n_retrievals_intr);
411 else if (ret == -ENODATA)
412 fscache_stat(&fscache_n_retrievals_nodata);
413 else if (ret < 0)
414 fscache_stat(&fscache_n_retrievals_nobufs);
415 else
416 fscache_stat(&fscache_n_retrievals_ok);
417
418 fscache_put_retrieval(op);
419 _leave(" = %d", ret);
420 return ret;
421
422 nobufs_unlock:
423 spin_unlock(&cookie->lock);
424 kfree(op);
425 nobufs:
426 fscache_stat(&fscache_n_retrievals_nobufs);
427 _leave(" = -ENOBUFS");
428 return -ENOBUFS;
429 }
430 EXPORT_SYMBOL(__fscache_read_or_alloc_pages);
431
432 /*
433 * allocate a block in the cache on which to store a page
434 * - we return:
435 * -ENOMEM - out of memory, nothing done
436 * -ERESTARTSYS - interrupted
437 * -ENOBUFS - no backing object available in which to cache the block
438 * 0 - block allocated
439 */
440 int __fscache_alloc_page(struct fscache_cookie *cookie,
441 struct page *page,
442 gfp_t gfp)
443 {
444 struct fscache_retrieval *op;
445 struct fscache_object *object;
446 int ret;
447
448 _enter("%p,%p,,,", cookie, page);
449
450 fscache_stat(&fscache_n_allocs);
451
452 if (hlist_empty(&cookie->backing_objects))
453 goto nobufs;
454
455 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
456 ASSERTCMP(page, !=, NULL);
457
458 if (fscache_wait_for_deferred_lookup(cookie) < 0)
459 return -ERESTARTSYS;
460
461 op = fscache_alloc_retrieval(page->mapping, NULL, NULL);
462 if (!op)
463 return -ENOMEM;
464
465 spin_lock(&cookie->lock);
466
467 if (hlist_empty(&cookie->backing_objects))
468 goto nobufs_unlock;
469 object = hlist_entry(cookie->backing_objects.first,
470 struct fscache_object, cookie_link);
471
472 if (fscache_submit_op(object, &op->op) < 0)
473 goto nobufs_unlock;
474 spin_unlock(&cookie->lock);
475
476 fscache_stat(&fscache_n_alloc_ops);
477
478 if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) {
479 _debug(">>> WT");
480 fscache_stat(&fscache_n_alloc_op_waits);
481 wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
482 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
483 _debug("<<< GO");
484 }
485
486 /* ask the cache to honour the operation */
487 ret = object->cache->ops->allocate_page(op, page, gfp);
488
489 if (ret < 0)
490 fscache_stat(&fscache_n_allocs_nobufs);
491 else
492 fscache_stat(&fscache_n_allocs_ok);
493
494 fscache_put_retrieval(op);
495 _leave(" = %d", ret);
496 return ret;
497
498 nobufs_unlock:
499 spin_unlock(&cookie->lock);
500 kfree(op);
501 nobufs:
502 fscache_stat(&fscache_n_allocs_nobufs);
503 _leave(" = -ENOBUFS");
504 return -ENOBUFS;
505 }
506 EXPORT_SYMBOL(__fscache_alloc_page);
507
508 /*
509 * release a write op reference
510 */
511 static void fscache_release_write_op(struct fscache_operation *_op)
512 {
513 _enter("{OP%x}", _op->debug_id);
514 }
515
516 /*
517 * perform the background storage of a page into the cache
518 */
519 static void fscache_write_op(struct fscache_operation *_op)
520 {
521 struct fscache_storage *op =
522 container_of(_op, struct fscache_storage, op);
523 struct fscache_object *object = op->op.object;
524 struct fscache_cookie *cookie = object->cookie;
525 struct page *page;
526 unsigned n;
527 void *results[1];
528 int ret;
529
530 _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage));
531
532 spin_lock(&cookie->lock);
533 spin_lock(&object->lock);
534
535 if (!fscache_object_is_active(object)) {
536 spin_unlock(&object->lock);
537 spin_unlock(&cookie->lock);
538 _leave("");
539 return;
540 }
541
542 fscache_stat(&fscache_n_store_calls);
543
544 /* find a page to store */
545 page = NULL;
546 n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
547 FSCACHE_COOKIE_PENDING_TAG);
548 if (n != 1)
549 goto superseded;
550 page = results[0];
551 _debug("gang %d [%lx]", n, page->index);
552 if (page->index > op->store_limit)
553 goto superseded;
554
555 radix_tree_tag_clear(&cookie->stores, page->index,
556 FSCACHE_COOKIE_PENDING_TAG);
557
558 spin_unlock(&object->lock);
559 spin_unlock(&cookie->lock);
560
561 if (page) {
562 ret = object->cache->ops->write_page(op, page);
563 fscache_end_page_write(cookie, page);
564 page_cache_release(page);
565 if (ret < 0)
566 fscache_abort_object(object);
567 else
568 fscache_enqueue_operation(&op->op);
569 }
570
571 _leave("");
572 return;
573
574 superseded:
575 /* this writer is going away and there aren't any more things to
576 * write */
577 _debug("cease");
578 clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
579 spin_unlock(&object->lock);
580 spin_unlock(&cookie->lock);
581 _leave("");
582 }
583
584 /*
585 * request a page be stored in the cache
586 * - returns:
587 * -ENOMEM - out of memory, nothing done
588 * -ENOBUFS - no backing object available in which to cache the page
589 * 0 - dispatched a write - it'll call end_io_func() when finished
590 *
591 * if the cookie still has a backing object at this point, that object can be
592 * in one of a few states with respect to storage processing:
593 *
594 * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is
595 * set)
596 *
597 * (a) no writes yet (set FSCACHE_COOKIE_PENDING_FILL and queue deferred
598 * fill op)
599 *
600 * (b) writes deferred till post-creation (mark page for writing and
601 * return immediately)
602 *
603 * (2) negative lookup, object created, initial fill being made from netfs
604 * (FSCACHE_COOKIE_INITIAL_FILL is set)
605 *
606 * (a) fill point not yet reached this page (mark page for writing and
607 * return)
608 *
609 * (b) fill point passed this page (queue op to store this page)
610 *
611 * (3) object extant (queue op to store this page)
612 *
613 * any other state is invalid
614 */
615 int __fscache_write_page(struct fscache_cookie *cookie,
616 struct page *page,
617 gfp_t gfp)
618 {
619 struct fscache_storage *op;
620 struct fscache_object *object;
621 int ret;
622
623 _enter("%p,%x,", cookie, (u32) page->flags);
624
625 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
626 ASSERT(PageFsCache(page));
627
628 fscache_stat(&fscache_n_stores);
629
630 op = kzalloc(sizeof(*op), GFP_NOIO);
631 if (!op)
632 goto nomem;
633
634 fscache_operation_init(&op->op, fscache_release_write_op);
635 fscache_operation_init_slow(&op->op, fscache_write_op);
636 op->op.flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_WAITING);
637
638 ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
639 if (ret < 0)
640 goto nomem_free;
641
642 ret = -ENOBUFS;
643 spin_lock(&cookie->lock);
644
645 if (hlist_empty(&cookie->backing_objects))
646 goto nobufs;
647 object = hlist_entry(cookie->backing_objects.first,
648 struct fscache_object, cookie_link);
649 if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
650 goto nobufs;
651
652 /* add the page to the pending-storage radix tree on the backing
653 * object */
654 spin_lock(&object->lock);
655
656 _debug("store limit %llx", (unsigned long long) object->store_limit);
657
658 ret = radix_tree_insert(&cookie->stores, page->index, page);
659 if (ret < 0) {
660 if (ret == -EEXIST)
661 goto already_queued;
662 _debug("insert failed %d", ret);
663 goto nobufs_unlock_obj;
664 }
665
666 radix_tree_tag_set(&cookie->stores, page->index,
667 FSCACHE_COOKIE_PENDING_TAG);
668 page_cache_get(page);
669
670 /* we only want one writer at a time, but we do need to queue new
671 * writers after exclusive ops */
672 if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags))
673 goto already_pending;
674
675 spin_unlock(&object->lock);
676
677 op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
678 op->store_limit = object->store_limit;
679
680 if (fscache_submit_op(object, &op->op) < 0)
681 goto submit_failed;
682
683 spin_unlock(&cookie->lock);
684 radix_tree_preload_end();
685 fscache_stat(&fscache_n_store_ops);
686 fscache_stat(&fscache_n_stores_ok);
687
688 /* the slow work queue now carries its own ref on the object */
689 fscache_put_operation(&op->op);
690 _leave(" = 0");
691 return 0;
692
693 already_queued:
694 fscache_stat(&fscache_n_stores_again);
695 already_pending:
696 spin_unlock(&object->lock);
697 spin_unlock(&cookie->lock);
698 radix_tree_preload_end();
699 kfree(op);
700 fscache_stat(&fscache_n_stores_ok);
701 _leave(" = 0");
702 return 0;
703
704 submit_failed:
705 radix_tree_delete(&cookie->stores, page->index);
706 page_cache_release(page);
707 ret = -ENOBUFS;
708 goto nobufs;
709
710 nobufs_unlock_obj:
711 spin_unlock(&object->lock);
712 nobufs:
713 spin_unlock(&cookie->lock);
714 radix_tree_preload_end();
715 kfree(op);
716 fscache_stat(&fscache_n_stores_nobufs);
717 _leave(" = -ENOBUFS");
718 return -ENOBUFS;
719
720 nomem_free:
721 kfree(op);
722 nomem:
723 fscache_stat(&fscache_n_stores_oom);
724 _leave(" = -ENOMEM");
725 return -ENOMEM;
726 }
727 EXPORT_SYMBOL(__fscache_write_page);
728
729 /*
730 * remove a page from the cache
731 */
732 void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page)
733 {
734 struct fscache_object *object;
735
736 _enter(",%p", page);
737
738 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
739 ASSERTCMP(page, !=, NULL);
740
741 fscache_stat(&fscache_n_uncaches);
742
743 /* cache withdrawal may beat us to it */
744 if (!PageFsCache(page))
745 goto done;
746
747 /* get the object */
748 spin_lock(&cookie->lock);
749
750 if (hlist_empty(&cookie->backing_objects)) {
751 ClearPageFsCache(page);
752 goto done_unlock;
753 }
754
755 object = hlist_entry(cookie->backing_objects.first,
756 struct fscache_object, cookie_link);
757
758 /* there might now be stuff on disk we could read */
759 clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
760
761 /* only invoke the cache backend if we managed to mark the page
762 * uncached here; this deals with synchronisation vs withdrawal */
763 if (TestClearPageFsCache(page) &&
764 object->cache->ops->uncache_page) {
765 /* the cache backend releases the cookie lock */
766 object->cache->ops->uncache_page(object, page);
767 goto done;
768 }
769
770 done_unlock:
771 spin_unlock(&cookie->lock);
772 done:
773 _leave("");
774 }
775 EXPORT_SYMBOL(__fscache_uncache_page);
776
777 /**
778 * fscache_mark_pages_cached - Mark pages as being cached
779 * @op: The retrieval op pages are being marked for
780 * @pagevec: The pages to be marked
781 *
782 * Mark a bunch of netfs pages as being cached. After this is called,
783 * the netfs must call fscache_uncache_page() to remove the mark.
784 */
785 void fscache_mark_pages_cached(struct fscache_retrieval *op,
786 struct pagevec *pagevec)
787 {
788 struct fscache_cookie *cookie = op->op.object->cookie;
789 unsigned long loop;
790
791 #ifdef CONFIG_FSCACHE_STATS
792 atomic_add(pagevec->nr, &fscache_n_marks);
793 #endif
794
795 for (loop = 0; loop < pagevec->nr; loop++) {
796 struct page *page = pagevec->pages[loop];
797
798 _debug("- mark %p{%lx}", page, page->index);
799 if (TestSetPageFsCache(page)) {
800 static bool once_only;
801 if (!once_only) {
802 once_only = true;
803 printk(KERN_WARNING "FS-Cache:"
804 " Cookie type %s marked page %lx"
805 " multiple times\n",
806 cookie->def->name, page->index);
807 }
808 }
809 }
810
811 if (cookie->def->mark_pages_cached)
812 cookie->def->mark_pages_cached(cookie->netfs_data,
813 op->mapping, pagevec);
814 pagevec_reinit(pagevec);
815 }
816 EXPORT_SYMBOL(fscache_mark_pages_cached);
Linux with added FPC-III support