1 /* Cache page management and data I/O routines
3 * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
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>
21 * check to see if a page is being written to the cache
23 bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page)
28 val = radix_tree_lookup(&cookie->stores, page->index);
33 EXPORT_SYMBOL(__fscache_check_page_write);
36 * wait for a page to finish being written to the cache
38 void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page)
40 wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
42 wait_event(*wq, !__fscache_check_page_write(cookie, page));
44 EXPORT_SYMBOL(__fscache_wait_on_page_write);
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
50 bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
57 _enter("%p,%p,%x", cookie, page, gfp);
61 val = radix_tree_lookup(&cookie->stores, page->index);
64 fscache_stat(&fscache_n_store_vmscan_not_storing);
65 __fscache_uncache_page(cookie, page);
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)) {
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);
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);
90 xpage = radix_tree_delete(&cookie->stores, page->index);
91 spin_unlock(&cookie->stores_lock);
94 fscache_stat(&fscache_n_store_vmscan_cancelled);
95 fscache_stat(&fscache_n_store_radix_deletes);
96 ASSERTCMP(xpage, ==, page);
98 fscache_stat(&fscache_n_store_vmscan_gone);
101 wake_up_bit(&cookie->flags, 0);
103 page_cache_release(xpage);
104 __fscache_uncache_page(cookie, page);
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
112 if (!(gfp & __GFP_WAIT) || !(gfp & __GFP_FS)) {
113 fscache_stat(&fscache_n_store_vmscan_busy);
117 fscache_stat(&fscache_n_store_vmscan_wait);
118 __fscache_wait_on_page_write(cookie, page);
122 EXPORT_SYMBOL(__fscache_maybe_release_page);
125 * note that a page has finished being written to the cache
127 static void fscache_end_page_write(struct fscache_object *object,
130 struct fscache_cookie *cookie;
131 struct page *xpage = NULL;
133 spin_lock(&object->lock);
134 cookie = object->cookie;
136 /* delete the page from the tree if it is now no longer
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);
146 spin_unlock(&cookie->stores_lock);
147 wake_up_bit(&cookie->flags, 0);
149 spin_unlock(&object->lock);
151 page_cache_release(xpage);
155 * actually apply the changed attributes to a cache object
157 static void fscache_attr_changed_op(struct fscache_operation *op)
159 struct fscache_object *object = op->object;
162 _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id);
164 fscache_stat(&fscache_n_attr_changed_calls);
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);
171 fscache_abort_object(object);
174 fscache_op_complete(op, true);
179 * notification that the attributes on an object have changed
181 int __fscache_attr_changed(struct fscache_cookie *cookie)
183 struct fscache_operation *op;
184 struct fscache_object *object;
187 _enter("%p", cookie);
189 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
191 fscache_stat(&fscache_n_attr_changed);
193 op = kzalloc(sizeof(*op), GFP_KERNEL);
195 fscache_stat(&fscache_n_attr_changed_nomem);
196 _leave(" = -ENOMEM");
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);
205 spin_lock(&cookie->lock);
207 if (!fscache_cookie_enabled(cookie) ||
208 hlist_empty(&cookie->backing_objects))
210 object = hlist_entry(cookie->backing_objects.first,
211 struct fscache_object, cookie_link);
213 __fscache_use_cookie(cookie);
214 if (fscache_submit_exclusive_op(object, op) < 0)
216 spin_unlock(&cookie->lock);
217 fscache_stat(&fscache_n_attr_changed_ok);
218 fscache_put_operation(op);
223 wake_cookie = __fscache_unuse_cookie(cookie);
224 spin_unlock(&cookie->lock);
227 __fscache_wake_unused_cookie(cookie);
228 fscache_stat(&fscache_n_attr_changed_nobufs);
229 _leave(" = %d", -ENOBUFS);
232 EXPORT_SYMBOL(__fscache_attr_changed);
235 * release a retrieval op reference
237 static void fscache_release_retrieval_op(struct fscache_operation *_op)
239 struct fscache_retrieval *op =
240 container_of(_op, struct fscache_retrieval, op);
242 _enter("{OP%x}", op->op.debug_id);
244 ASSERTCMP(atomic_read(&op->n_pages), ==, 0);
246 fscache_hist(fscache_retrieval_histogram, op->start_time);
248 fscache_put_context(op->op.object->cookie, op->context);
254 * allocate a retrieval op
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,
262 struct fscache_retrieval *op;
264 /* allocate a retrieval operation and attempt to submit it */
265 op = kzalloc(sizeof(*op), GFP_NOIO);
267 fscache_stat(&fscache_n_retrievals_nomem);
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);
284 * wait for a deferred lookup to complete
286 int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
292 if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
293 _leave(" = 0 [imm]");
297 fscache_stat(&fscache_n_retrievals_wait);
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");
307 ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
310 fscache_hist(fscache_retrieval_delay_histogram, jif);
311 _leave(" = 0 [dly]");
316 * Handle cancellation of a pending retrieval op
318 static void fscache_do_cancel_retrieval(struct fscache_operation *_op)
320 struct fscache_retrieval *op =
321 container_of(_op, struct fscache_retrieval, op);
323 atomic_set(&op->n_pages, 0);
327 * wait for an object to become active (or dead)
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 *))
337 if (!test_bit(FSCACHE_OP_WAITING, &op->flags))
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);
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);
357 if (op->state == FSCACHE_OP_ST_CANCELLED) {
358 if (stat_object_dead)
359 fscache_stat(stat_object_dead);
360 _leave(" = -ENOBUFS [cancelled]");
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);
374 * read a page from the cache or allocate a block in which to store it
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
382 int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
384 fscache_rw_complete_t end_io_func,
388 struct fscache_retrieval *op;
389 struct fscache_object *object;
390 bool wake_cookie = false;
393 _enter("%p,%p,,,", cookie, page);
395 fscache_stat(&fscache_n_retrievals);
397 if (hlist_empty(&cookie->backing_objects))
400 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
401 _leave(" = -ENOBUFS [invalidating]");
405 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
406 ASSERTCMP(page, !=, NULL);
408 if (fscache_wait_for_deferred_lookup(cookie) < 0)
411 op = fscache_alloc_retrieval(cookie, page->mapping,
412 end_io_func, context);
414 _leave(" = -ENOMEM");
417 atomic_set(&op->n_pages, 1);
419 spin_lock(&cookie->lock);
421 if (!fscache_cookie_enabled(cookie) ||
422 hlist_empty(&cookie->backing_objects))
424 object = hlist_entry(cookie->backing_objects.first,
425 struct fscache_object, cookie_link);
427 ASSERT(test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags));
429 __fscache_use_cookie(cookie);
430 atomic_inc(&object->n_reads);
431 __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
433 if (fscache_submit_op(object, &op->op) < 0)
434 goto nobufs_unlock_dec;
435 spin_unlock(&cookie->lock);
437 fscache_stat(&fscache_n_retrieval_ops);
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);
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(
447 __fscache_stat(&fscache_n_retrieval_op_waits),
448 __fscache_stat(&fscache_n_retrievals_object_dead),
449 fscache_do_cancel_retrieval);
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);
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);
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);
474 fscache_stat(&fscache_n_retrievals_nobufs);
476 fscache_stat(&fscache_n_retrievals_ok);
478 fscache_put_retrieval(op);
479 _leave(" = %d", ret);
483 atomic_dec(&object->n_reads);
484 wake_cookie = __fscache_unuse_cookie(cookie);
486 spin_unlock(&cookie->lock);
488 __fscache_wake_unused_cookie(cookie);
491 fscache_stat(&fscache_n_retrievals_nobufs);
492 _leave(" = -ENOBUFS");
495 EXPORT_SYMBOL(__fscache_read_or_alloc_page);
498 * read a list of page from the cache or allocate a block in which to store
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
507 * 0 - dispatched a read on all pages
509 * end_io_func() will be called for each page read from the cache as it is
510 * finishes being read
512 * any pages for which a read is dispatched will be removed from pages and
515 int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
516 struct address_space *mapping,
517 struct list_head *pages,
519 fscache_rw_complete_t end_io_func,
523 struct fscache_retrieval *op;
524 struct fscache_object *object;
525 bool wake_cookie = false;
528 _enter("%p,,%d,,,", cookie, *nr_pages);
530 fscache_stat(&fscache_n_retrievals);
532 if (hlist_empty(&cookie->backing_objects))
535 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
536 _leave(" = -ENOBUFS [invalidating]");
540 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
541 ASSERTCMP(*nr_pages, >, 0);
542 ASSERT(!list_empty(pages));
544 if (fscache_wait_for_deferred_lookup(cookie) < 0)
547 op = fscache_alloc_retrieval(cookie, mapping, end_io_func, context);
550 atomic_set(&op->n_pages, *nr_pages);
552 spin_lock(&cookie->lock);
554 if (!fscache_cookie_enabled(cookie) ||
555 hlist_empty(&cookie->backing_objects))
557 object = hlist_entry(cookie->backing_objects.first,
558 struct fscache_object, cookie_link);
560 __fscache_use_cookie(cookie);
561 atomic_inc(&object->n_reads);
562 __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
564 if (fscache_submit_op(object, &op->op) < 0)
565 goto nobufs_unlock_dec;
566 spin_unlock(&cookie->lock);
568 fscache_stat(&fscache_n_retrieval_ops);
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);
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(
578 __fscache_stat(&fscache_n_retrieval_op_waits),
579 __fscache_stat(&fscache_n_retrievals_object_dead),
580 fscache_do_cancel_retrieval);
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);
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);
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);
605 fscache_stat(&fscache_n_retrievals_nobufs);
607 fscache_stat(&fscache_n_retrievals_ok);
609 fscache_put_retrieval(op);
610 _leave(" = %d", ret);
614 atomic_dec(&object->n_reads);
615 wake_cookie = __fscache_unuse_cookie(cookie);
617 spin_unlock(&cookie->lock);
620 __fscache_wake_unused_cookie(cookie);
622 fscache_stat(&fscache_n_retrievals_nobufs);
623 _leave(" = -ENOBUFS");
626 EXPORT_SYMBOL(__fscache_read_or_alloc_pages);
629 * allocate a block in the cache on which to store a page
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
636 int __fscache_alloc_page(struct fscache_cookie *cookie,
640 struct fscache_retrieval *op;
641 struct fscache_object *object;
642 bool wake_cookie = false;
645 _enter("%p,%p,,,", cookie, page);
647 fscache_stat(&fscache_n_allocs);
649 if (hlist_empty(&cookie->backing_objects))
652 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
653 ASSERTCMP(page, !=, NULL);
655 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
656 _leave(" = -ENOBUFS [invalidating]");
660 if (fscache_wait_for_deferred_lookup(cookie) < 0)
663 op = fscache_alloc_retrieval(cookie, page->mapping, NULL, NULL);
666 atomic_set(&op->n_pages, 1);
668 spin_lock(&cookie->lock);
670 if (!fscache_cookie_enabled(cookie) ||
671 hlist_empty(&cookie->backing_objects))
673 object = hlist_entry(cookie->backing_objects.first,
674 struct fscache_object, cookie_link);
676 __fscache_use_cookie(cookie);
677 if (fscache_submit_op(object, &op->op) < 0)
678 goto nobufs_unlock_dec;
679 spin_unlock(&cookie->lock);
681 fscache_stat(&fscache_n_alloc_ops);
683 ret = fscache_wait_for_operation_activation(
685 __fscache_stat(&fscache_n_alloc_op_waits),
686 __fscache_stat(&fscache_n_allocs_object_dead),
687 fscache_do_cancel_retrieval);
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);
697 if (ret == -ERESTARTSYS)
698 fscache_stat(&fscache_n_allocs_intr);
700 fscache_stat(&fscache_n_allocs_nobufs);
702 fscache_stat(&fscache_n_allocs_ok);
704 fscache_put_retrieval(op);
705 _leave(" = %d", ret);
709 wake_cookie = __fscache_unuse_cookie(cookie);
711 spin_unlock(&cookie->lock);
714 __fscache_wake_unused_cookie(cookie);
716 fscache_stat(&fscache_n_allocs_nobufs);
717 _leave(" = -ENOBUFS");
720 EXPORT_SYMBOL(__fscache_alloc_page);
723 * Unmark pages allocate in the readahead code path (via:
724 * fscache_readpages_or_alloc) after delegating to the base filesystem
726 void __fscache_readpages_cancel(struct fscache_cookie *cookie,
727 struct list_head *pages)
731 list_for_each_entry(page, pages, lru) {
732 if (PageFsCache(page))
733 __fscache_uncache_page(cookie, page);
736 EXPORT_SYMBOL(__fscache_readpages_cancel);
739 * release a write op reference
741 static void fscache_release_write_op(struct fscache_operation *_op)
743 _enter("{OP%x}", _op->debug_id);
747 * perform the background storage of a page into the cache
749 static void fscache_write_op(struct fscache_operation *_op)
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;
760 _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage));
762 spin_lock(&object->lock);
763 cookie = object->cookie;
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.
769 spin_unlock(&object->lock);
770 fscache_op_complete(&op->op, false);
771 _leave(" [inactive]");
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.
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,
790 spin_lock(&cookie->stores_lock);
792 fscache_stat(&fscache_n_store_calls);
794 /* find a page to store */
796 n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
797 FSCACHE_COOKIE_PENDING_TAG);
801 _debug("gang %d [%lx]", n, page->index);
802 if (page->index > op->store_limit) {
803 fscache_stat(&fscache_n_store_pages_over_limit);
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);
812 spin_unlock(&cookie->stores_lock);
813 spin_unlock(&object->lock);
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);
821 fscache_abort_object(object);
822 fscache_op_complete(&op->op, true);
824 fscache_enqueue_operation(&op->op);
831 /* this writer is going away and there aren't any more things to
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);
842 * Clear the pages pending writing for invalidation
844 void fscache_invalidate_writes(struct fscache_cookie *cookie)
853 spin_lock(&cookie->stores_lock);
854 n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
856 FSCACHE_COOKIE_PENDING_TAG);
858 spin_unlock(&cookie->stores_lock);
862 for (i = n - 1; i >= 0; i--) {
864 radix_tree_delete(&cookie->stores, page->index);
867 spin_unlock(&cookie->stores_lock);
869 for (i = n - 1; i >= 0; i--)
870 page_cache_release(results[i]);
877 * request a page be stored in the cache
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
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:
886 * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is
891 * (b) writes deferred till post-creation (mark page for writing and
892 * return immediately)
894 * (2) negative lookup, object created, initial fill being made from netfs
896 * (a) fill point not yet reached this page (mark page for writing and
899 * (b) fill point passed this page (queue op to store this page)
901 * (3) object extant (queue op to store this page)
903 * any other state is invalid
905 int __fscache_write_page(struct fscache_cookie *cookie,
909 struct fscache_storage *op;
910 struct fscache_object *object;
911 bool wake_cookie = false;
914 _enter("%p,%x,", cookie, (u32) page->flags);
916 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
917 ASSERT(PageFsCache(page));
919 fscache_stat(&fscache_n_stores);
921 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
922 _leave(" = -ENOBUFS [invalidating]");
926 op = kzalloc(sizeof(*op), GFP_NOIO | __GFP_NOMEMALLOC | __GFP_NORETRY);
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);
936 ret = radix_tree_maybe_preload(gfp & ~__GFP_HIGHMEM);
941 spin_lock(&cookie->lock);
943 if (!fscache_cookie_enabled(cookie) ||
944 hlist_empty(&cookie->backing_objects))
946 object = hlist_entry(cookie->backing_objects.first,
947 struct fscache_object, cookie_link);
948 if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
951 /* add the page to the pending-storage radix tree on the backing
953 spin_lock(&object->lock);
954 spin_lock(&cookie->stores_lock);
956 _debug("store limit %llx", (unsigned long long) object->store_limit);
958 ret = radix_tree_insert(&cookie->stores, page->index, page);
962 _debug("insert failed %d", ret);
963 goto nobufs_unlock_obj;
966 radix_tree_tag_set(&cookie->stores, page->index,
967 FSCACHE_COOKIE_PENDING_TAG);
968 page_cache_get(page);
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;
975 spin_unlock(&cookie->stores_lock);
976 spin_unlock(&object->lock);
978 op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
979 op->store_limit = object->store_limit;
981 __fscache_use_cookie(cookie);
982 if (fscache_submit_op(object, &op->op) < 0)
985 spin_unlock(&cookie->lock);
986 radix_tree_preload_end();
987 fscache_stat(&fscache_n_store_ops);
988 fscache_stat(&fscache_n_stores_ok);
990 /* the work queue now carries its own ref on the object */
991 fscache_put_operation(&op->op);
996 fscache_stat(&fscache_n_stores_again);
998 spin_unlock(&cookie->stores_lock);
999 spin_unlock(&object->lock);
1000 spin_unlock(&cookie->lock);
1001 radix_tree_preload_end();
1003 fscache_stat(&fscache_n_stores_ok);
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);
1017 spin_unlock(&cookie->stores_lock);
1018 spin_unlock(&object->lock);
1020 spin_unlock(&cookie->lock);
1021 radix_tree_preload_end();
1024 __fscache_wake_unused_cookie(cookie);
1025 fscache_stat(&fscache_n_stores_nobufs);
1026 _leave(" = -ENOBUFS");
1032 fscache_stat(&fscache_n_stores_oom);
1033 _leave(" = -ENOMEM");
1036 EXPORT_SYMBOL(__fscache_write_page);
1039 * remove a page from the cache
1041 void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page)
1043 struct fscache_object *object;
1045 _enter(",%p", page);
1047 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
1048 ASSERTCMP(page, !=, NULL);
1050 fscache_stat(&fscache_n_uncaches);
1052 /* cache withdrawal may beat us to it */
1053 if (!PageFsCache(page))
1056 /* get the object */
1057 spin_lock(&cookie->lock);
1059 if (hlist_empty(&cookie->backing_objects)) {
1060 ClearPageFsCache(page);
1064 object = hlist_entry(cookie->backing_objects.first,
1065 struct fscache_object, cookie_link);
1067 /* there might now be stuff on disk we could read */
1068 clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
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);
1082 spin_unlock(&cookie->lock);
1086 EXPORT_SYMBOL(__fscache_uncache_page);
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
1093 * Mark a netfs page as being cached. After this is called, the netfs
1094 * must call fscache_uncache_page() to remove the mark.
1096 void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page)
1098 struct fscache_cookie *cookie = op->op.object->cookie;
1100 #ifdef CONFIG_FSCACHE_STATS
1101 atomic_inc(&fscache_n_marks);
1104 _debug("- mark %p{%lx}", page, page->index);
1105 if (TestSetPageFsCache(page)) {
1106 static bool once_only;
1109 pr_warn("Cookie type %s marked page %lx multiple times\n",
1110 cookie->def->name, page->index);
1114 if (cookie->def->mark_page_cached)
1115 cookie->def->mark_page_cached(cookie->netfs_data,
1118 EXPORT_SYMBOL(fscache_mark_page_cached);
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
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.
1128 void fscache_mark_pages_cached(struct fscache_retrieval *op,
1129 struct pagevec *pagevec)
1133 for (loop = 0; loop < pagevec->nr; loop++)
1134 fscache_mark_page_cached(op, pagevec->pages[loop]);
1136 pagevec_reinit(pagevec);
1138 EXPORT_SYMBOL(fscache_mark_pages_cached);
1141 * Uncache all the pages in an inode that are marked PG_fscache, assuming them
1142 * to be associated with the given cookie.
1144 void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
1145 struct inode *inode)
1147 struct address_space *mapping = inode->i_mapping;
1148 struct pagevec pvec;
1152 _enter("%p,%p", cookie, inode);
1154 if (!mapping || mapping->nrpages == 0) {
1155 _leave(" [no pages]");
1159 pagevec_init(&pvec, 0);
1162 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
1164 for (i = 0; i < pagevec_count(&pvec); i++) {
1165 struct page *page = pvec.pages[i];
1167 if (PageFsCache(page)) {
1168 __fscache_wait_on_page_write(cookie, page);
1169 __fscache_uncache_page(cookie, page);
1172 pagevec_release(&pvec);
1178 EXPORT_SYMBOL(__fscache_uncache_all_inode_pages);