blob: 5b5d9081c8b2849ef819f3645adface6ade7591b [file] [log] [blame]
David Howellsb5108822009-04-03 16:42:39 +01001/* 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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090017#include <linux/slab.h>
David Howellsb5108822009-04-03 16:42:39 +010018#include "internal.h"
19
20/*
21 * check to see if a page is being written to the cache
22 */
23bool __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}
33EXPORT_SYMBOL(__fscache_check_page_write);
34
35/*
36 * wait for a page to finish being written to the cache
37 */
38void __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}
44EXPORT_SYMBOL(__fscache_wait_on_page_write);
45
46/*
David Howells201a1542009-11-19 18:11:35 +000047 * 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 */
50bool __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
David Howells8c209ce2012-12-05 13:34:49 +000059try_again:
David Howells201a1542009-11-19 18:11:35 +000060 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
107page_busy:
David Howells8c209ce2012-12-05 13:34:49 +0000108 /* 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)) {
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;
David Howells201a1542009-11-19 18:11:35 +0000121}
122EXPORT_SYMBOL(__fscache_maybe_release_page);
123
124/*
David Howellsb5108822009-04-03 16:42:39 +0100125 * note that a page has finished being written to the cache
126 */
David Howells1bccf512009-11-19 18:11:25 +0000127static void fscache_end_page_write(struct fscache_object *object,
128 struct page *page)
David Howellsb5108822009-04-03 16:42:39 +0100129{
David Howells1bccf512009-11-19 18:11:25 +0000130 struct fscache_cookie *cookie;
131 struct page *xpage = NULL;
David Howellsb5108822009-04-03 16:42:39 +0100132
David Howells1bccf512009-11-19 18:11:25 +0000133 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);
David Howells201a1542009-11-19 18:11:35 +0000139 radix_tree_tag_clear(&cookie->stores, page->index,
140 FSCACHE_COOKIE_STORING_TAG);
David Howells285e7282009-11-19 18:11:29 +0000141 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 }
David Howells1bccf512009-11-19 18:11:25 +0000146 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);
David Howellsb5108822009-04-03 16:42:39 +0100152}
153
154/*
155 * actually apply the changed attributes to a cache object
156 */
157static void fscache_attr_changed_op(struct fscache_operation *op)
158{
159 struct fscache_object *object = op->object;
David Howells440f0af2009-11-19 18:11:01 +0000160 int ret;
David Howellsb5108822009-04-03 16:42:39 +0100161
162 _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id);
163
164 fscache_stat(&fscache_n_attr_changed_calls);
165
David Howells440f0af2009-11-19 18:11:01 +0000166 if (fscache_object_is_active(object)) {
David Howells52bd75f2009-11-19 18:11:08 +0000167 fscache_stat(&fscache_n_cop_attr_changed);
David Howells440f0af2009-11-19 18:11:01 +0000168 ret = object->cache->ops->attr_changed(object);
David Howells52bd75f2009-11-19 18:11:08 +0000169 fscache_stat_d(&fscache_n_cop_attr_changed);
David Howells440f0af2009-11-19 18:11:01 +0000170 if (ret < 0)
171 fscache_abort_object(object);
172 }
David Howellsb5108822009-04-03 16:42:39 +0100173
David Howells9f105232012-12-20 21:52:35 +0000174 fscache_op_complete(op);
David Howellsb5108822009-04-03 16:42:39 +0100175 _leave("");
176}
177
178/*
179 * notification that the attributes on an object have changed
180 */
181int __fscache_attr_changed(struct fscache_cookie *cookie)
182{
183 struct fscache_operation *op;
184 struct fscache_object *object;
185
186 _enter("%p", cookie);
187
188 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
189
190 fscache_stat(&fscache_n_attr_changed);
191
192 op = kzalloc(sizeof(*op), GFP_KERNEL);
193 if (!op) {
194 fscache_stat(&fscache_n_attr_changed_nomem);
195 _leave(" = -ENOMEM");
196 return -ENOMEM;
197 }
198
Tejun Heo8af7c122010-07-20 22:09:01 +0200199 fscache_operation_init(op, fscache_attr_changed_op, NULL);
200 op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE);
David Howellsb5108822009-04-03 16:42:39 +0100201
202 spin_lock(&cookie->lock);
203
204 if (hlist_empty(&cookie->backing_objects))
205 goto nobufs;
206 object = hlist_entry(cookie->backing_objects.first,
207 struct fscache_object, cookie_link);
208
209 if (fscache_submit_exclusive_op(object, op) < 0)
210 goto nobufs;
211 spin_unlock(&cookie->lock);
212 fscache_stat(&fscache_n_attr_changed_ok);
213 fscache_put_operation(op);
214 _leave(" = 0");
215 return 0;
216
217nobufs:
218 spin_unlock(&cookie->lock);
219 kfree(op);
220 fscache_stat(&fscache_n_attr_changed_nobufs);
221 _leave(" = %d", -ENOBUFS);
222 return -ENOBUFS;
223}
224EXPORT_SYMBOL(__fscache_attr_changed);
225
226/*
David Howellsb5108822009-04-03 16:42:39 +0100227 * release a retrieval op reference
228 */
229static void fscache_release_retrieval_op(struct fscache_operation *_op)
230{
231 struct fscache_retrieval *op =
232 container_of(_op, struct fscache_retrieval, op);
233
234 _enter("{OP%x}", op->op.debug_id);
235
David Howells9f105232012-12-20 21:52:35 +0000236 ASSERTCMP(op->n_pages, ==, 0);
237
David Howellsb5108822009-04-03 16:42:39 +0100238 fscache_hist(fscache_retrieval_histogram, op->start_time);
239 if (op->context)
240 fscache_put_context(op->op.object->cookie, op->context);
241
242 _leave("");
243}
244
245/*
246 * allocate a retrieval op
247 */
248static struct fscache_retrieval *fscache_alloc_retrieval(
249 struct address_space *mapping,
250 fscache_rw_complete_t end_io_func,
251 void *context)
252{
253 struct fscache_retrieval *op;
254
255 /* allocate a retrieval operation and attempt to submit it */
256 op = kzalloc(sizeof(*op), GFP_NOIO);
257 if (!op) {
258 fscache_stat(&fscache_n_retrievals_nomem);
259 return NULL;
260 }
261
Tejun Heo8af7c122010-07-20 22:09:01 +0200262 fscache_operation_init(&op->op, NULL, fscache_release_retrieval_op);
David Howellsb5108822009-04-03 16:42:39 +0100263 op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING);
264 op->mapping = mapping;
265 op->end_io_func = end_io_func;
266 op->context = context;
267 op->start_time = jiffies;
David Howellsb5108822009-04-03 16:42:39 +0100268 INIT_LIST_HEAD(&op->to_do);
269 return op;
270}
271
272/*
273 * wait for a deferred lookup to complete
274 */
275static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
276{
277 unsigned long jif;
278
279 _enter("");
280
281 if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
282 _leave(" = 0 [imm]");
283 return 0;
284 }
285
286 fscache_stat(&fscache_n_retrievals_wait);
287
288 jif = jiffies;
289 if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
290 fscache_wait_bit_interruptible,
291 TASK_INTERRUPTIBLE) != 0) {
292 fscache_stat(&fscache_n_retrievals_intr);
293 _leave(" = -ERESTARTSYS");
294 return -ERESTARTSYS;
295 }
296
297 ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
298
299 smp_rmb();
300 fscache_hist(fscache_retrieval_delay_histogram, jif);
301 _leave(" = 0 [dly]");
302 return 0;
303}
304
305/*
David Howells60d543c2009-11-19 18:11:45 +0000306 * wait for an object to become active (or dead)
307 */
308static int fscache_wait_for_retrieval_activation(struct fscache_object *object,
309 struct fscache_retrieval *op,
310 atomic_t *stat_op_waits,
311 atomic_t *stat_object_dead)
312{
313 int ret;
314
315 if (!test_bit(FSCACHE_OP_WAITING, &op->op.flags))
316 goto check_if_dead;
317
318 _debug(">>> WT");
319 fscache_stat(stat_op_waits);
320 if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
321 fscache_wait_bit_interruptible,
David Howells9c04caa2012-12-07 18:08:02 +0000322 TASK_INTERRUPTIBLE) != 0) {
David Howells60d543c2009-11-19 18:11:45 +0000323 ret = fscache_cancel_op(&op->op);
324 if (ret == 0)
325 return -ERESTARTSYS;
326
327 /* it's been removed from the pending queue by another party,
328 * so we should get to run shortly */
329 wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
330 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
331 }
332 _debug("<<< GO");
333
334check_if_dead:
David Howells9f105232012-12-20 21:52:35 +0000335 if (op->op.state == FSCACHE_OP_ST_CANCELLED) {
336 fscache_stat(stat_object_dead);
337 _leave(" = -ENOBUFS [cancelled]");
338 return -ENOBUFS;
339 }
David Howells60d543c2009-11-19 18:11:45 +0000340 if (unlikely(fscache_object_is_dead(object))) {
David Howellsb4cf1e02012-12-05 13:34:45 +0000341 pr_err("%s() = -ENOBUFS [obj dead %d]", __func__, op->op.state);
342 fscache_cancel_op(&op->op);
David Howells60d543c2009-11-19 18:11:45 +0000343 fscache_stat(stat_object_dead);
344 return -ENOBUFS;
345 }
346 return 0;
347}
348
349/*
David Howellsb5108822009-04-03 16:42:39 +0100350 * read a page from the cache or allocate a block in which to store it
351 * - we return:
352 * -ENOMEM - out of memory, nothing done
353 * -ERESTARTSYS - interrupted
354 * -ENOBUFS - no backing object available in which to cache the block
355 * -ENODATA - no data available in the backing object for this block
356 * 0 - dispatched a read - it'll call end_io_func() when finished
357 */
358int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
359 struct page *page,
360 fscache_rw_complete_t end_io_func,
361 void *context,
362 gfp_t gfp)
363{
364 struct fscache_retrieval *op;
365 struct fscache_object *object;
366 int ret;
367
368 _enter("%p,%p,,,", cookie, page);
369
370 fscache_stat(&fscache_n_retrievals);
371
372 if (hlist_empty(&cookie->backing_objects))
373 goto nobufs;
374
David Howellsef778e72012-12-20 21:52:36 +0000375 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
376 _leave(" = -ENOBUFS [invalidating]");
377 return -ENOBUFS;
378 }
379
David Howellsb5108822009-04-03 16:42:39 +0100380 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
381 ASSERTCMP(page, !=, NULL);
382
383 if (fscache_wait_for_deferred_lookup(cookie) < 0)
384 return -ERESTARTSYS;
385
386 op = fscache_alloc_retrieval(page->mapping, end_io_func, context);
387 if (!op) {
388 _leave(" = -ENOMEM");
389 return -ENOMEM;
390 }
David Howells9f105232012-12-20 21:52:35 +0000391 op->n_pages = 1;
David Howellsb5108822009-04-03 16:42:39 +0100392
393 spin_lock(&cookie->lock);
394
395 if (hlist_empty(&cookie->backing_objects))
396 goto nobufs_unlock;
397 object = hlist_entry(cookie->backing_objects.first,
398 struct fscache_object, cookie_link);
399
400 ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP);
401
David Howells4fbf4292009-11-19 18:11:04 +0000402 atomic_inc(&object->n_reads);
David Howells9f105232012-12-20 21:52:35 +0000403 __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
David Howells4fbf4292009-11-19 18:11:04 +0000404
David Howellsb5108822009-04-03 16:42:39 +0100405 if (fscache_submit_op(object, &op->op) < 0)
David Howells9f105232012-12-20 21:52:35 +0000406 goto nobufs_unlock_dec;
David Howellsb5108822009-04-03 16:42:39 +0100407 spin_unlock(&cookie->lock);
408
409 fscache_stat(&fscache_n_retrieval_ops);
410
411 /* pin the netfs read context in case we need to do the actual netfs
412 * read because we've encountered a cache read failure */
413 fscache_get_context(object->cookie, op->context);
414
415 /* we wait for the operation to become active, and then process it
416 * *here*, in this thread, and not in the thread pool */
David Howells60d543c2009-11-19 18:11:45 +0000417 ret = fscache_wait_for_retrieval_activation(
418 object, op,
419 __fscache_stat(&fscache_n_retrieval_op_waits),
420 __fscache_stat(&fscache_n_retrievals_object_dead));
421 if (ret < 0)
422 goto error;
David Howellsb5108822009-04-03 16:42:39 +0100423
424 /* ask the cache to honour the operation */
425 if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
David Howells52bd75f2009-11-19 18:11:08 +0000426 fscache_stat(&fscache_n_cop_allocate_page);
David Howellsb5108822009-04-03 16:42:39 +0100427 ret = object->cache->ops->allocate_page(op, page, gfp);
David Howells52bd75f2009-11-19 18:11:08 +0000428 fscache_stat_d(&fscache_n_cop_allocate_page);
David Howellsb5108822009-04-03 16:42:39 +0100429 if (ret == 0)
430 ret = -ENODATA;
431 } else {
David Howells52bd75f2009-11-19 18:11:08 +0000432 fscache_stat(&fscache_n_cop_read_or_alloc_page);
David Howellsb5108822009-04-03 16:42:39 +0100433 ret = object->cache->ops->read_or_alloc_page(op, page, gfp);
David Howells52bd75f2009-11-19 18:11:08 +0000434 fscache_stat_d(&fscache_n_cop_read_or_alloc_page);
David Howellsb5108822009-04-03 16:42:39 +0100435 }
436
David Howells5753c442009-11-19 18:11:19 +0000437error:
David Howellsb5108822009-04-03 16:42:39 +0100438 if (ret == -ENOMEM)
439 fscache_stat(&fscache_n_retrievals_nomem);
440 else if (ret == -ERESTARTSYS)
441 fscache_stat(&fscache_n_retrievals_intr);
442 else if (ret == -ENODATA)
443 fscache_stat(&fscache_n_retrievals_nodata);
444 else if (ret < 0)
445 fscache_stat(&fscache_n_retrievals_nobufs);
446 else
447 fscache_stat(&fscache_n_retrievals_ok);
448
449 fscache_put_retrieval(op);
450 _leave(" = %d", ret);
451 return ret;
452
David Howells9f105232012-12-20 21:52:35 +0000453nobufs_unlock_dec:
454 atomic_dec(&object->n_reads);
David Howellsb5108822009-04-03 16:42:39 +0100455nobufs_unlock:
456 spin_unlock(&cookie->lock);
457 kfree(op);
458nobufs:
459 fscache_stat(&fscache_n_retrievals_nobufs);
460 _leave(" = -ENOBUFS");
461 return -ENOBUFS;
462}
463EXPORT_SYMBOL(__fscache_read_or_alloc_page);
464
465/*
466 * read a list of page from the cache or allocate a block in which to store
467 * them
468 * - we return:
469 * -ENOMEM - out of memory, some pages may be being read
470 * -ERESTARTSYS - interrupted, some pages may be being read
471 * -ENOBUFS - no backing object or space available in which to cache any
472 * pages not being read
473 * -ENODATA - no data available in the backing object for some or all of
474 * the pages
475 * 0 - dispatched a read on all pages
476 *
477 * end_io_func() will be called for each page read from the cache as it is
478 * finishes being read
479 *
480 * any pages for which a read is dispatched will be removed from pages and
481 * nr_pages
482 */
483int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
484 struct address_space *mapping,
485 struct list_head *pages,
486 unsigned *nr_pages,
487 fscache_rw_complete_t end_io_func,
488 void *context,
489 gfp_t gfp)
490{
David Howellsb5108822009-04-03 16:42:39 +0100491 struct fscache_retrieval *op;
492 struct fscache_object *object;
493 int ret;
494
495 _enter("%p,,%d,,,", cookie, *nr_pages);
496
497 fscache_stat(&fscache_n_retrievals);
498
499 if (hlist_empty(&cookie->backing_objects))
500 goto nobufs;
501
David Howellsef778e72012-12-20 21:52:36 +0000502 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
503 _leave(" = -ENOBUFS [invalidating]");
504 return -ENOBUFS;
505 }
506
David Howellsb5108822009-04-03 16:42:39 +0100507 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
508 ASSERTCMP(*nr_pages, >, 0);
509 ASSERT(!list_empty(pages));
510
511 if (fscache_wait_for_deferred_lookup(cookie) < 0)
512 return -ERESTARTSYS;
513
514 op = fscache_alloc_retrieval(mapping, end_io_func, context);
515 if (!op)
516 return -ENOMEM;
David Howells9f105232012-12-20 21:52:35 +0000517 op->n_pages = *nr_pages;
David Howellsb5108822009-04-03 16:42:39 +0100518
519 spin_lock(&cookie->lock);
520
521 if (hlist_empty(&cookie->backing_objects))
522 goto nobufs_unlock;
523 object = hlist_entry(cookie->backing_objects.first,
524 struct fscache_object, cookie_link);
525
David Howells4fbf4292009-11-19 18:11:04 +0000526 atomic_inc(&object->n_reads);
David Howells9f105232012-12-20 21:52:35 +0000527 __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
David Howells4fbf4292009-11-19 18:11:04 +0000528
David Howellsb5108822009-04-03 16:42:39 +0100529 if (fscache_submit_op(object, &op->op) < 0)
David Howells9f105232012-12-20 21:52:35 +0000530 goto nobufs_unlock_dec;
David Howellsb5108822009-04-03 16:42:39 +0100531 spin_unlock(&cookie->lock);
532
533 fscache_stat(&fscache_n_retrieval_ops);
534
535 /* pin the netfs read context in case we need to do the actual netfs
536 * read because we've encountered a cache read failure */
537 fscache_get_context(object->cookie, op->context);
538
539 /* we wait for the operation to become active, and then process it
540 * *here*, in this thread, and not in the thread pool */
David Howells60d543c2009-11-19 18:11:45 +0000541 ret = fscache_wait_for_retrieval_activation(
542 object, op,
543 __fscache_stat(&fscache_n_retrieval_op_waits),
544 __fscache_stat(&fscache_n_retrievals_object_dead));
545 if (ret < 0)
546 goto error;
David Howellsb5108822009-04-03 16:42:39 +0100547
548 /* ask the cache to honour the operation */
David Howells52bd75f2009-11-19 18:11:08 +0000549 if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
550 fscache_stat(&fscache_n_cop_allocate_pages);
551 ret = object->cache->ops->allocate_pages(
552 op, pages, nr_pages, gfp);
553 fscache_stat_d(&fscache_n_cop_allocate_pages);
554 } else {
555 fscache_stat(&fscache_n_cop_read_or_alloc_pages);
556 ret = object->cache->ops->read_or_alloc_pages(
557 op, pages, nr_pages, gfp);
558 fscache_stat_d(&fscache_n_cop_read_or_alloc_pages);
559 }
David Howellsb5108822009-04-03 16:42:39 +0100560
David Howells5753c442009-11-19 18:11:19 +0000561error:
David Howellsb5108822009-04-03 16:42:39 +0100562 if (ret == -ENOMEM)
563 fscache_stat(&fscache_n_retrievals_nomem);
564 else if (ret == -ERESTARTSYS)
565 fscache_stat(&fscache_n_retrievals_intr);
566 else if (ret == -ENODATA)
567 fscache_stat(&fscache_n_retrievals_nodata);
568 else if (ret < 0)
569 fscache_stat(&fscache_n_retrievals_nobufs);
570 else
571 fscache_stat(&fscache_n_retrievals_ok);
572
573 fscache_put_retrieval(op);
574 _leave(" = %d", ret);
575 return ret;
576
David Howells9f105232012-12-20 21:52:35 +0000577nobufs_unlock_dec:
578 atomic_dec(&object->n_reads);
David Howellsb5108822009-04-03 16:42:39 +0100579nobufs_unlock:
580 spin_unlock(&cookie->lock);
581 kfree(op);
582nobufs:
583 fscache_stat(&fscache_n_retrievals_nobufs);
584 _leave(" = -ENOBUFS");
585 return -ENOBUFS;
586}
587EXPORT_SYMBOL(__fscache_read_or_alloc_pages);
588
589/*
590 * allocate a block in the cache on which to store a page
591 * - we return:
592 * -ENOMEM - out of memory, nothing done
593 * -ERESTARTSYS - interrupted
594 * -ENOBUFS - no backing object available in which to cache the block
595 * 0 - block allocated
596 */
597int __fscache_alloc_page(struct fscache_cookie *cookie,
598 struct page *page,
599 gfp_t gfp)
600{
601 struct fscache_retrieval *op;
602 struct fscache_object *object;
603 int ret;
604
605 _enter("%p,%p,,,", cookie, page);
606
607 fscache_stat(&fscache_n_allocs);
608
609 if (hlist_empty(&cookie->backing_objects))
610 goto nobufs;
611
612 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
613 ASSERTCMP(page, !=, NULL);
614
David Howellsef778e72012-12-20 21:52:36 +0000615 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
616 _leave(" = -ENOBUFS [invalidating]");
617 return -ENOBUFS;
618 }
619
David Howellsb5108822009-04-03 16:42:39 +0100620 if (fscache_wait_for_deferred_lookup(cookie) < 0)
621 return -ERESTARTSYS;
622
623 op = fscache_alloc_retrieval(page->mapping, NULL, NULL);
624 if (!op)
625 return -ENOMEM;
David Howells9f105232012-12-20 21:52:35 +0000626 op->n_pages = 1;
David Howellsb5108822009-04-03 16:42:39 +0100627
628 spin_lock(&cookie->lock);
629
630 if (hlist_empty(&cookie->backing_objects))
631 goto nobufs_unlock;
632 object = hlist_entry(cookie->backing_objects.first,
633 struct fscache_object, cookie_link);
634
635 if (fscache_submit_op(object, &op->op) < 0)
636 goto nobufs_unlock;
637 spin_unlock(&cookie->lock);
638
639 fscache_stat(&fscache_n_alloc_ops);
640
David Howells60d543c2009-11-19 18:11:45 +0000641 ret = fscache_wait_for_retrieval_activation(
642 object, op,
643 __fscache_stat(&fscache_n_alloc_op_waits),
644 __fscache_stat(&fscache_n_allocs_object_dead));
645 if (ret < 0)
646 goto error;
David Howellsb5108822009-04-03 16:42:39 +0100647
648 /* ask the cache to honour the operation */
David Howells52bd75f2009-11-19 18:11:08 +0000649 fscache_stat(&fscache_n_cop_allocate_page);
David Howellsb5108822009-04-03 16:42:39 +0100650 ret = object->cache->ops->allocate_page(op, page, gfp);
David Howells52bd75f2009-11-19 18:11:08 +0000651 fscache_stat_d(&fscache_n_cop_allocate_page);
David Howellsb5108822009-04-03 16:42:39 +0100652
David Howells5753c442009-11-19 18:11:19 +0000653error:
654 if (ret == -ERESTARTSYS)
655 fscache_stat(&fscache_n_allocs_intr);
656 else if (ret < 0)
David Howellsb5108822009-04-03 16:42:39 +0100657 fscache_stat(&fscache_n_allocs_nobufs);
658 else
659 fscache_stat(&fscache_n_allocs_ok);
660
661 fscache_put_retrieval(op);
662 _leave(" = %d", ret);
663 return ret;
664
665nobufs_unlock:
666 spin_unlock(&cookie->lock);
667 kfree(op);
668nobufs:
669 fscache_stat(&fscache_n_allocs_nobufs);
670 _leave(" = -ENOBUFS");
671 return -ENOBUFS;
672}
673EXPORT_SYMBOL(__fscache_alloc_page);
674
675/*
676 * release a write op reference
677 */
678static void fscache_release_write_op(struct fscache_operation *_op)
679{
680 _enter("{OP%x}", _op->debug_id);
681}
682
683/*
684 * perform the background storage of a page into the cache
685 */
686static void fscache_write_op(struct fscache_operation *_op)
687{
688 struct fscache_storage *op =
689 container_of(_op, struct fscache_storage, op);
690 struct fscache_object *object = op->op.object;
David Howells1bccf512009-11-19 18:11:25 +0000691 struct fscache_cookie *cookie;
David Howellsb5108822009-04-03 16:42:39 +0100692 struct page *page;
693 unsigned n;
694 void *results[1];
695 int ret;
696
697 _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage));
698
David Howellsb5108822009-04-03 16:42:39 +0100699 spin_lock(&object->lock);
David Howells1bccf512009-11-19 18:11:25 +0000700 cookie = object->cookie;
David Howellsb5108822009-04-03 16:42:39 +0100701
David Howells1bccf512009-11-19 18:11:25 +0000702 if (!fscache_object_is_active(object) || !cookie) {
David Howellsb5108822009-04-03 16:42:39 +0100703 spin_unlock(&object->lock);
David Howellsb5108822009-04-03 16:42:39 +0100704 _leave("");
705 return;
706 }
707
David Howells1bccf512009-11-19 18:11:25 +0000708 spin_lock(&cookie->stores_lock);
709
David Howellsb5108822009-04-03 16:42:39 +0100710 fscache_stat(&fscache_n_store_calls);
711
712 /* find a page to store */
713 page = NULL;
714 n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
715 FSCACHE_COOKIE_PENDING_TAG);
716 if (n != 1)
717 goto superseded;
718 page = results[0];
719 _debug("gang %d [%lx]", n, page->index);
David Howells1bccf512009-11-19 18:11:25 +0000720 if (page->index > op->store_limit) {
721 fscache_stat(&fscache_n_store_pages_over_limit);
David Howellsb5108822009-04-03 16:42:39 +0100722 goto superseded;
David Howells1bccf512009-11-19 18:11:25 +0000723 }
David Howellsb5108822009-04-03 16:42:39 +0100724
Dan Carpenter08a66852010-06-01 20:58:22 +0100725 radix_tree_tag_set(&cookie->stores, page->index,
726 FSCACHE_COOKIE_STORING_TAG);
727 radix_tree_tag_clear(&cookie->stores, page->index,
728 FSCACHE_COOKIE_PENDING_TAG);
David Howellsb5108822009-04-03 16:42:39 +0100729
David Howells1bccf512009-11-19 18:11:25 +0000730 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100731 spin_unlock(&object->lock);
David Howellsb5108822009-04-03 16:42:39 +0100732
Dan Carpenter08a66852010-06-01 20:58:22 +0100733 fscache_stat(&fscache_n_store_pages);
734 fscache_stat(&fscache_n_cop_write_page);
735 ret = object->cache->ops->write_page(op, page);
736 fscache_stat_d(&fscache_n_cop_write_page);
Dan Carpenter08a66852010-06-01 20:58:22 +0100737 fscache_end_page_write(object, page);
738 if (ret < 0) {
Dan Carpenter08a66852010-06-01 20:58:22 +0100739 fscache_abort_object(object);
David Howells9f105232012-12-20 21:52:35 +0000740 fscache_op_complete(&op->op);
Dan Carpenter08a66852010-06-01 20:58:22 +0100741 } else {
742 fscache_enqueue_operation(&op->op);
David Howellsb5108822009-04-03 16:42:39 +0100743 }
744
745 _leave("");
746 return;
747
748superseded:
749 /* this writer is going away and there aren't any more things to
750 * write */
751 _debug("cease");
David Howells1bccf512009-11-19 18:11:25 +0000752 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100753 clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
754 spin_unlock(&object->lock);
David Howells9f105232012-12-20 21:52:35 +0000755 fscache_op_complete(&op->op);
David Howellsb5108822009-04-03 16:42:39 +0100756 _leave("");
757}
758
759/*
David Howellsef778e72012-12-20 21:52:36 +0000760 * Clear the pages pending writing for invalidation
761 */
762void fscache_invalidate_writes(struct fscache_cookie *cookie)
763{
764 struct page *page;
765 void *results[16];
766 int n, i;
767
768 _enter("");
769
770 while (spin_lock(&cookie->stores_lock),
771 n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
772 ARRAY_SIZE(results),
773 FSCACHE_COOKIE_PENDING_TAG),
774 n > 0) {
775 for (i = n - 1; i >= 0; i--) {
776 page = results[i];
777 radix_tree_delete(&cookie->stores, page->index);
778 }
779
780 spin_unlock(&cookie->stores_lock);
781
782 for (i = n - 1; i >= 0; i--)
783 page_cache_release(results[i]);
784 }
785
786 spin_unlock(&cookie->stores_lock);
787 _leave("");
788}
789
790/*
David Howellsb5108822009-04-03 16:42:39 +0100791 * request a page be stored in the cache
792 * - returns:
793 * -ENOMEM - out of memory, nothing done
794 * -ENOBUFS - no backing object available in which to cache the page
795 * 0 - dispatched a write - it'll call end_io_func() when finished
796 *
797 * if the cookie still has a backing object at this point, that object can be
798 * in one of a few states with respect to storage processing:
799 *
800 * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is
801 * set)
802 *
803 * (a) no writes yet (set FSCACHE_COOKIE_PENDING_FILL and queue deferred
804 * fill op)
805 *
806 * (b) writes deferred till post-creation (mark page for writing and
807 * return immediately)
808 *
809 * (2) negative lookup, object created, initial fill being made from netfs
810 * (FSCACHE_COOKIE_INITIAL_FILL is set)
811 *
812 * (a) fill point not yet reached this page (mark page for writing and
813 * return)
814 *
815 * (b) fill point passed this page (queue op to store this page)
816 *
817 * (3) object extant (queue op to store this page)
818 *
819 * any other state is invalid
820 */
821int __fscache_write_page(struct fscache_cookie *cookie,
822 struct page *page,
823 gfp_t gfp)
824{
825 struct fscache_storage *op;
826 struct fscache_object *object;
827 int ret;
828
829 _enter("%p,%x,", cookie, (u32) page->flags);
830
831 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
832 ASSERT(PageFsCache(page));
833
834 fscache_stat(&fscache_n_stores);
835
David Howellsef778e72012-12-20 21:52:36 +0000836 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
837 _leave(" = -ENOBUFS [invalidating]");
838 return -ENOBUFS;
839 }
840
David Howells5f4f9f42012-12-20 21:52:33 +0000841 op = kzalloc(sizeof(*op), GFP_NOIO | __GFP_NOMEMALLOC | __GFP_NORETRY);
David Howellsb5108822009-04-03 16:42:39 +0100842 if (!op)
843 goto nomem;
844
Tejun Heo8af7c122010-07-20 22:09:01 +0200845 fscache_operation_init(&op->op, fscache_write_op,
846 fscache_release_write_op);
847 op->op.flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_WAITING);
David Howellsb5108822009-04-03 16:42:39 +0100848
849 ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
850 if (ret < 0)
851 goto nomem_free;
852
853 ret = -ENOBUFS;
854 spin_lock(&cookie->lock);
855
856 if (hlist_empty(&cookie->backing_objects))
857 goto nobufs;
858 object = hlist_entry(cookie->backing_objects.first,
859 struct fscache_object, cookie_link);
860 if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
861 goto nobufs;
862
863 /* add the page to the pending-storage radix tree on the backing
864 * object */
865 spin_lock(&object->lock);
David Howells1bccf512009-11-19 18:11:25 +0000866 spin_lock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100867
868 _debug("store limit %llx", (unsigned long long) object->store_limit);
869
870 ret = radix_tree_insert(&cookie->stores, page->index, page);
871 if (ret < 0) {
872 if (ret == -EEXIST)
873 goto already_queued;
874 _debug("insert failed %d", ret);
875 goto nobufs_unlock_obj;
876 }
877
878 radix_tree_tag_set(&cookie->stores, page->index,
879 FSCACHE_COOKIE_PENDING_TAG);
880 page_cache_get(page);
881
882 /* we only want one writer at a time, but we do need to queue new
883 * writers after exclusive ops */
884 if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags))
885 goto already_pending;
886
David Howells1bccf512009-11-19 18:11:25 +0000887 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100888 spin_unlock(&object->lock);
889
890 op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
891 op->store_limit = object->store_limit;
892
893 if (fscache_submit_op(object, &op->op) < 0)
894 goto submit_failed;
895
896 spin_unlock(&cookie->lock);
897 radix_tree_preload_end();
898 fscache_stat(&fscache_n_store_ops);
899 fscache_stat(&fscache_n_stores_ok);
900
Tejun Heo8af7c122010-07-20 22:09:01 +0200901 /* the work queue now carries its own ref on the object */
David Howellsb5108822009-04-03 16:42:39 +0100902 fscache_put_operation(&op->op);
903 _leave(" = 0");
904 return 0;
905
906already_queued:
907 fscache_stat(&fscache_n_stores_again);
908already_pending:
David Howells1bccf512009-11-19 18:11:25 +0000909 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100910 spin_unlock(&object->lock);
911 spin_unlock(&cookie->lock);
912 radix_tree_preload_end();
913 kfree(op);
914 fscache_stat(&fscache_n_stores_ok);
915 _leave(" = 0");
916 return 0;
917
918submit_failed:
David Howells1bccf512009-11-19 18:11:25 +0000919 spin_lock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100920 radix_tree_delete(&cookie->stores, page->index);
David Howells1bccf512009-11-19 18:11:25 +0000921 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100922 page_cache_release(page);
923 ret = -ENOBUFS;
924 goto nobufs;
925
926nobufs_unlock_obj:
Dan Carpenter1147d0f2010-03-23 14:48:37 +0000927 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100928 spin_unlock(&object->lock);
929nobufs:
930 spin_unlock(&cookie->lock);
931 radix_tree_preload_end();
932 kfree(op);
933 fscache_stat(&fscache_n_stores_nobufs);
934 _leave(" = -ENOBUFS");
935 return -ENOBUFS;
936
937nomem_free:
938 kfree(op);
939nomem:
940 fscache_stat(&fscache_n_stores_oom);
941 _leave(" = -ENOMEM");
942 return -ENOMEM;
943}
944EXPORT_SYMBOL(__fscache_write_page);
945
946/*
947 * remove a page from the cache
948 */
949void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page)
950{
951 struct fscache_object *object;
952
953 _enter(",%p", page);
954
955 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
956 ASSERTCMP(page, !=, NULL);
957
958 fscache_stat(&fscache_n_uncaches);
959
960 /* cache withdrawal may beat us to it */
961 if (!PageFsCache(page))
962 goto done;
963
964 /* get the object */
965 spin_lock(&cookie->lock);
966
967 if (hlist_empty(&cookie->backing_objects)) {
968 ClearPageFsCache(page);
969 goto done_unlock;
970 }
971
972 object = hlist_entry(cookie->backing_objects.first,
973 struct fscache_object, cookie_link);
974
975 /* there might now be stuff on disk we could read */
976 clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
977
978 /* only invoke the cache backend if we managed to mark the page
979 * uncached here; this deals with synchronisation vs withdrawal */
980 if (TestClearPageFsCache(page) &&
981 object->cache->ops->uncache_page) {
982 /* the cache backend releases the cookie lock */
David Howells52bd75f2009-11-19 18:11:08 +0000983 fscache_stat(&fscache_n_cop_uncache_page);
David Howellsb5108822009-04-03 16:42:39 +0100984 object->cache->ops->uncache_page(object, page);
David Howells52bd75f2009-11-19 18:11:08 +0000985 fscache_stat_d(&fscache_n_cop_uncache_page);
David Howellsb5108822009-04-03 16:42:39 +0100986 goto done;
987 }
988
989done_unlock:
990 spin_unlock(&cookie->lock);
991done:
992 _leave("");
993}
994EXPORT_SYMBOL(__fscache_uncache_page);
995
996/**
David Howellsc4d6d8d2012-12-20 21:52:32 +0000997 * fscache_mark_page_cached - Mark a page as being cached
998 * @op: The retrieval op pages are being marked for
999 * @page: The page to be marked
1000 *
1001 * Mark a netfs page as being cached. After this is called, the netfs
1002 * must call fscache_uncache_page() to remove the mark.
1003 */
1004void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page)
1005{
1006 struct fscache_cookie *cookie = op->op.object->cookie;
1007
1008#ifdef CONFIG_FSCACHE_STATS
1009 atomic_inc(&fscache_n_marks);
1010#endif
1011
1012 _debug("- mark %p{%lx}", page, page->index);
1013 if (TestSetPageFsCache(page)) {
1014 static bool once_only;
1015 if (!once_only) {
1016 once_only = true;
1017 printk(KERN_WARNING "FS-Cache:"
1018 " Cookie type %s marked page %lx"
1019 " multiple times\n",
1020 cookie->def->name, page->index);
1021 }
1022 }
1023
1024 if (cookie->def->mark_page_cached)
1025 cookie->def->mark_page_cached(cookie->netfs_data,
1026 op->mapping, page);
1027}
1028EXPORT_SYMBOL(fscache_mark_page_cached);
1029
1030/**
David Howellsb5108822009-04-03 16:42:39 +01001031 * fscache_mark_pages_cached - Mark pages as being cached
1032 * @op: The retrieval op pages are being marked for
1033 * @pagevec: The pages to be marked
1034 *
1035 * Mark a bunch of netfs pages as being cached. After this is called,
1036 * the netfs must call fscache_uncache_page() to remove the mark.
1037 */
1038void fscache_mark_pages_cached(struct fscache_retrieval *op,
1039 struct pagevec *pagevec)
1040{
David Howellsb5108822009-04-03 16:42:39 +01001041 unsigned long loop;
1042
David Howellsc4d6d8d2012-12-20 21:52:32 +00001043 for (loop = 0; loop < pagevec->nr; loop++)
1044 fscache_mark_page_cached(op, pagevec->pages[loop]);
David Howellsb5108822009-04-03 16:42:39 +01001045
David Howellsb5108822009-04-03 16:42:39 +01001046 pagevec_reinit(pagevec);
1047}
1048EXPORT_SYMBOL(fscache_mark_pages_cached);
David Howellsc902ce12011-07-07 12:19:48 +01001049
1050/*
1051 * Uncache all the pages in an inode that are marked PG_fscache, assuming them
1052 * to be associated with the given cookie.
1053 */
1054void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
1055 struct inode *inode)
1056{
1057 struct address_space *mapping = inode->i_mapping;
1058 struct pagevec pvec;
1059 pgoff_t next;
1060 int i;
1061
1062 _enter("%p,%p", cookie, inode);
1063
1064 if (!mapping || mapping->nrpages == 0) {
1065 _leave(" [no pages]");
1066 return;
1067 }
1068
1069 pagevec_init(&pvec, 0);
1070 next = 0;
Jan Beulichb307d462011-07-21 15:02:43 +01001071 do {
1072 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
1073 break;
David Howellsc902ce12011-07-07 12:19:48 +01001074 for (i = 0; i < pagevec_count(&pvec); i++) {
1075 struct page *page = pvec.pages[i];
Jan Beulichb307d462011-07-21 15:02:43 +01001076 next = page->index;
David Howellsc902ce12011-07-07 12:19:48 +01001077 if (PageFsCache(page)) {
1078 __fscache_wait_on_page_write(cookie, page);
1079 __fscache_uncache_page(cookie, page);
1080 }
1081 }
1082 pagevec_release(&pvec);
1083 cond_resched();
Jan Beulichb307d462011-07-21 15:02:43 +01001084 } while (++next);
David Howellsc902ce12011-07-07 12:19:48 +01001085
1086 _leave("");
1087}
1088EXPORT_SYMBOL(__fscache_uncache_all_inode_pages);