Commit | Line | Data |
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b5108822 DH |
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> | |
5a0e3ad6 | 17 | #include <linux/slab.h> |
b5108822 DH |
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 | ||
201a1542 DH |
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 | rcu_read_lock(); | |
60 | val = radix_tree_lookup(&cookie->stores, page->index); | |
61 | if (!val) { | |
62 | rcu_read_unlock(); | |
63 | fscache_stat(&fscache_n_store_vmscan_not_storing); | |
64 | __fscache_uncache_page(cookie, page); | |
65 | return true; | |
66 | } | |
67 | ||
68 | /* see if the page is actually undergoing storage - if so we can't get | |
69 | * rid of it till the cache has finished with it */ | |
70 | if (radix_tree_tag_get(&cookie->stores, page->index, | |
71 | FSCACHE_COOKIE_STORING_TAG)) { | |
72 | rcu_read_unlock(); | |
73 | goto page_busy; | |
74 | } | |
75 | ||
76 | /* the page is pending storage, so we attempt to cancel the store and | |
77 | * discard the store request so that the page can be reclaimed */ | |
78 | spin_lock(&cookie->stores_lock); | |
79 | rcu_read_unlock(); | |
80 | ||
81 | if (radix_tree_tag_get(&cookie->stores, page->index, | |
82 | FSCACHE_COOKIE_STORING_TAG)) { | |
83 | /* the page started to undergo storage whilst we were looking, | |
84 | * so now we can only wait or return */ | |
85 | spin_unlock(&cookie->stores_lock); | |
86 | goto page_busy; | |
87 | } | |
88 | ||
89 | xpage = radix_tree_delete(&cookie->stores, page->index); | |
90 | spin_unlock(&cookie->stores_lock); | |
91 | ||
92 | if (xpage) { | |
93 | fscache_stat(&fscache_n_store_vmscan_cancelled); | |
94 | fscache_stat(&fscache_n_store_radix_deletes); | |
95 | ASSERTCMP(xpage, ==, page); | |
96 | } else { | |
97 | fscache_stat(&fscache_n_store_vmscan_gone); | |
98 | } | |
99 | ||
100 | wake_up_bit(&cookie->flags, 0); | |
101 | if (xpage) | |
102 | page_cache_release(xpage); | |
103 | __fscache_uncache_page(cookie, page); | |
104 | return true; | |
105 | ||
106 | page_busy: | |
107 | /* we might want to wait here, but that could deadlock the allocator as | |
8af7c124 | 108 | * the work threads writing to the cache may all end up sleeping |
201a1542 DH |
109 | * on memory allocation */ |
110 | fscache_stat(&fscache_n_store_vmscan_busy); | |
111 | return false; | |
112 | } | |
113 | EXPORT_SYMBOL(__fscache_maybe_release_page); | |
114 | ||
b5108822 DH |
115 | /* |
116 | * note that a page has finished being written to the cache | |
117 | */ | |
1bccf513 DH |
118 | static void fscache_end_page_write(struct fscache_object *object, |
119 | struct page *page) | |
b5108822 | 120 | { |
1bccf513 DH |
121 | struct fscache_cookie *cookie; |
122 | struct page *xpage = NULL; | |
b5108822 | 123 | |
1bccf513 DH |
124 | spin_lock(&object->lock); |
125 | cookie = object->cookie; | |
126 | if (cookie) { | |
127 | /* delete the page from the tree if it is now no longer | |
128 | * pending */ | |
129 | spin_lock(&cookie->stores_lock); | |
201a1542 DH |
130 | radix_tree_tag_clear(&cookie->stores, page->index, |
131 | FSCACHE_COOKIE_STORING_TAG); | |
285e728b DH |
132 | if (!radix_tree_tag_get(&cookie->stores, page->index, |
133 | FSCACHE_COOKIE_PENDING_TAG)) { | |
134 | fscache_stat(&fscache_n_store_radix_deletes); | |
135 | xpage = radix_tree_delete(&cookie->stores, page->index); | |
136 | } | |
1bccf513 DH |
137 | spin_unlock(&cookie->stores_lock); |
138 | wake_up_bit(&cookie->flags, 0); | |
139 | } | |
140 | spin_unlock(&object->lock); | |
141 | if (xpage) | |
142 | page_cache_release(xpage); | |
b5108822 DH |
143 | } |
144 | ||
145 | /* | |
146 | * actually apply the changed attributes to a cache object | |
147 | */ | |
148 | static void fscache_attr_changed_op(struct fscache_operation *op) | |
149 | { | |
150 | struct fscache_object *object = op->object; | |
440f0aff | 151 | int ret; |
b5108822 DH |
152 | |
153 | _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id); | |
154 | ||
155 | fscache_stat(&fscache_n_attr_changed_calls); | |
156 | ||
440f0aff | 157 | if (fscache_object_is_active(object)) { |
52bd75fd | 158 | fscache_stat(&fscache_n_cop_attr_changed); |
440f0aff | 159 | ret = object->cache->ops->attr_changed(object); |
52bd75fd | 160 | fscache_stat_d(&fscache_n_cop_attr_changed); |
440f0aff DH |
161 | if (ret < 0) |
162 | fscache_abort_object(object); | |
163 | } | |
b5108822 DH |
164 | |
165 | _leave(""); | |
166 | } | |
167 | ||
168 | /* | |
169 | * notification that the attributes on an object have changed | |
170 | */ | |
171 | int __fscache_attr_changed(struct fscache_cookie *cookie) | |
172 | { | |
173 | struct fscache_operation *op; | |
174 | struct fscache_object *object; | |
175 | ||
176 | _enter("%p", cookie); | |
177 | ||
178 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
179 | ||
180 | fscache_stat(&fscache_n_attr_changed); | |
181 | ||
182 | op = kzalloc(sizeof(*op), GFP_KERNEL); | |
183 | if (!op) { | |
184 | fscache_stat(&fscache_n_attr_changed_nomem); | |
185 | _leave(" = -ENOMEM"); | |
186 | return -ENOMEM; | |
187 | } | |
188 | ||
8af7c124 TH |
189 | fscache_operation_init(op, fscache_attr_changed_op, NULL); |
190 | op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE); | |
b5108822 DH |
191 | |
192 | spin_lock(&cookie->lock); | |
193 | ||
194 | if (hlist_empty(&cookie->backing_objects)) | |
195 | goto nobufs; | |
196 | object = hlist_entry(cookie->backing_objects.first, | |
197 | struct fscache_object, cookie_link); | |
198 | ||
199 | if (fscache_submit_exclusive_op(object, op) < 0) | |
200 | goto nobufs; | |
201 | spin_unlock(&cookie->lock); | |
202 | fscache_stat(&fscache_n_attr_changed_ok); | |
203 | fscache_put_operation(op); | |
204 | _leave(" = 0"); | |
205 | return 0; | |
206 | ||
207 | nobufs: | |
208 | spin_unlock(&cookie->lock); | |
209 | kfree(op); | |
210 | fscache_stat(&fscache_n_attr_changed_nobufs); | |
211 | _leave(" = %d", -ENOBUFS); | |
212 | return -ENOBUFS; | |
213 | } | |
214 | EXPORT_SYMBOL(__fscache_attr_changed); | |
215 | ||
b5108822 DH |
216 | /* |
217 | * release a retrieval op reference | |
218 | */ | |
219 | static void fscache_release_retrieval_op(struct fscache_operation *_op) | |
220 | { | |
221 | struct fscache_retrieval *op = | |
222 | container_of(_op, struct fscache_retrieval, op); | |
223 | ||
224 | _enter("{OP%x}", op->op.debug_id); | |
225 | ||
226 | fscache_hist(fscache_retrieval_histogram, op->start_time); | |
227 | if (op->context) | |
228 | fscache_put_context(op->op.object->cookie, op->context); | |
229 | ||
230 | _leave(""); | |
231 | } | |
232 | ||
233 | /* | |
234 | * allocate a retrieval op | |
235 | */ | |
236 | static struct fscache_retrieval *fscache_alloc_retrieval( | |
237 | struct address_space *mapping, | |
238 | fscache_rw_complete_t end_io_func, | |
239 | void *context) | |
240 | { | |
241 | struct fscache_retrieval *op; | |
242 | ||
243 | /* allocate a retrieval operation and attempt to submit it */ | |
244 | op = kzalloc(sizeof(*op), GFP_NOIO); | |
245 | if (!op) { | |
246 | fscache_stat(&fscache_n_retrievals_nomem); | |
247 | return NULL; | |
248 | } | |
249 | ||
8af7c124 | 250 | fscache_operation_init(&op->op, NULL, fscache_release_retrieval_op); |
b5108822 DH |
251 | op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING); |
252 | op->mapping = mapping; | |
253 | op->end_io_func = end_io_func; | |
254 | op->context = context; | |
255 | op->start_time = jiffies; | |
b5108822 DH |
256 | INIT_LIST_HEAD(&op->to_do); |
257 | return op; | |
258 | } | |
259 | ||
260 | /* | |
261 | * wait for a deferred lookup to complete | |
262 | */ | |
263 | static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie) | |
264 | { | |
265 | unsigned long jif; | |
266 | ||
267 | _enter(""); | |
268 | ||
269 | if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) { | |
270 | _leave(" = 0 [imm]"); | |
271 | return 0; | |
272 | } | |
273 | ||
274 | fscache_stat(&fscache_n_retrievals_wait); | |
275 | ||
276 | jif = jiffies; | |
277 | if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP, | |
278 | fscache_wait_bit_interruptible, | |
279 | TASK_INTERRUPTIBLE) != 0) { | |
280 | fscache_stat(&fscache_n_retrievals_intr); | |
281 | _leave(" = -ERESTARTSYS"); | |
282 | return -ERESTARTSYS; | |
283 | } | |
284 | ||
285 | ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)); | |
286 | ||
287 | smp_rmb(); | |
288 | fscache_hist(fscache_retrieval_delay_histogram, jif); | |
289 | _leave(" = 0 [dly]"); | |
290 | return 0; | |
291 | } | |
292 | ||
60d543ca DH |
293 | /* |
294 | * wait for an object to become active (or dead) | |
295 | */ | |
296 | static int fscache_wait_for_retrieval_activation(struct fscache_object *object, | |
297 | struct fscache_retrieval *op, | |
298 | atomic_t *stat_op_waits, | |
299 | atomic_t *stat_object_dead) | |
300 | { | |
301 | int ret; | |
302 | ||
303 | if (!test_bit(FSCACHE_OP_WAITING, &op->op.flags)) | |
304 | goto check_if_dead; | |
305 | ||
306 | _debug(">>> WT"); | |
307 | fscache_stat(stat_op_waits); | |
308 | if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, | |
309 | fscache_wait_bit_interruptible, | |
310 | TASK_INTERRUPTIBLE) < 0) { | |
311 | ret = fscache_cancel_op(&op->op); | |
312 | if (ret == 0) | |
313 | return -ERESTARTSYS; | |
314 | ||
315 | /* it's been removed from the pending queue by another party, | |
316 | * so we should get to run shortly */ | |
317 | wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, | |
318 | fscache_wait_bit, TASK_UNINTERRUPTIBLE); | |
319 | } | |
320 | _debug("<<< GO"); | |
321 | ||
322 | check_if_dead: | |
323 | if (unlikely(fscache_object_is_dead(object))) { | |
324 | fscache_stat(stat_object_dead); | |
325 | return -ENOBUFS; | |
326 | } | |
327 | return 0; | |
328 | } | |
329 | ||
b5108822 DH |
330 | /* |
331 | * read a page from the cache or allocate a block in which to store it | |
332 | * - we return: | |
333 | * -ENOMEM - out of memory, nothing done | |
334 | * -ERESTARTSYS - interrupted | |
335 | * -ENOBUFS - no backing object available in which to cache the block | |
336 | * -ENODATA - no data available in the backing object for this block | |
337 | * 0 - dispatched a read - it'll call end_io_func() when finished | |
338 | */ | |
339 | int __fscache_read_or_alloc_page(struct fscache_cookie *cookie, | |
340 | struct page *page, | |
341 | fscache_rw_complete_t end_io_func, | |
342 | void *context, | |
343 | gfp_t gfp) | |
344 | { | |
345 | struct fscache_retrieval *op; | |
346 | struct fscache_object *object; | |
347 | int ret; | |
348 | ||
349 | _enter("%p,%p,,,", cookie, page); | |
350 | ||
351 | fscache_stat(&fscache_n_retrievals); | |
352 | ||
353 | if (hlist_empty(&cookie->backing_objects)) | |
354 | goto nobufs; | |
355 | ||
356 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
357 | ASSERTCMP(page, !=, NULL); | |
358 | ||
359 | if (fscache_wait_for_deferred_lookup(cookie) < 0) | |
360 | return -ERESTARTSYS; | |
361 | ||
362 | op = fscache_alloc_retrieval(page->mapping, end_io_func, context); | |
363 | if (!op) { | |
364 | _leave(" = -ENOMEM"); | |
365 | return -ENOMEM; | |
366 | } | |
367 | ||
368 | spin_lock(&cookie->lock); | |
369 | ||
370 | if (hlist_empty(&cookie->backing_objects)) | |
371 | goto nobufs_unlock; | |
372 | object = hlist_entry(cookie->backing_objects.first, | |
373 | struct fscache_object, cookie_link); | |
374 | ||
375 | ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP); | |
376 | ||
4fbf4291 DH |
377 | atomic_inc(&object->n_reads); |
378 | set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags); | |
379 | ||
b5108822 DH |
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 */ | |
60d543ca DH |
392 | ret = fscache_wait_for_retrieval_activation( |
393 | object, op, | |
394 | __fscache_stat(&fscache_n_retrieval_op_waits), | |
395 | __fscache_stat(&fscache_n_retrievals_object_dead)); | |
396 | if (ret < 0) | |
397 | goto error; | |
b5108822 DH |
398 | |
399 | /* ask the cache to honour the operation */ | |
400 | if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { | |
52bd75fd | 401 | fscache_stat(&fscache_n_cop_allocate_page); |
b5108822 | 402 | ret = object->cache->ops->allocate_page(op, page, gfp); |
52bd75fd | 403 | fscache_stat_d(&fscache_n_cop_allocate_page); |
b5108822 DH |
404 | if (ret == 0) |
405 | ret = -ENODATA; | |
406 | } else { | |
52bd75fd | 407 | fscache_stat(&fscache_n_cop_read_or_alloc_page); |
b5108822 | 408 | ret = object->cache->ops->read_or_alloc_page(op, page, gfp); |
52bd75fd | 409 | fscache_stat_d(&fscache_n_cop_read_or_alloc_page); |
b5108822 DH |
410 | } |
411 | ||
5753c441 | 412 | error: |
b5108822 DH |
413 | if (ret == -ENOMEM) |
414 | fscache_stat(&fscache_n_retrievals_nomem); | |
415 | else if (ret == -ERESTARTSYS) | |
416 | fscache_stat(&fscache_n_retrievals_intr); | |
417 | else if (ret == -ENODATA) | |
418 | fscache_stat(&fscache_n_retrievals_nodata); | |
419 | else if (ret < 0) | |
420 | fscache_stat(&fscache_n_retrievals_nobufs); | |
421 | else | |
422 | fscache_stat(&fscache_n_retrievals_ok); | |
423 | ||
424 | fscache_put_retrieval(op); | |
425 | _leave(" = %d", ret); | |
426 | return ret; | |
427 | ||
428 | nobufs_unlock: | |
429 | spin_unlock(&cookie->lock); | |
430 | kfree(op); | |
431 | nobufs: | |
432 | fscache_stat(&fscache_n_retrievals_nobufs); | |
433 | _leave(" = -ENOBUFS"); | |
434 | return -ENOBUFS; | |
435 | } | |
436 | EXPORT_SYMBOL(__fscache_read_or_alloc_page); | |
437 | ||
438 | /* | |
439 | * read a list of page from the cache or allocate a block in which to store | |
440 | * them | |
441 | * - we return: | |
442 | * -ENOMEM - out of memory, some pages may be being read | |
443 | * -ERESTARTSYS - interrupted, some pages may be being read | |
444 | * -ENOBUFS - no backing object or space available in which to cache any | |
445 | * pages not being read | |
446 | * -ENODATA - no data available in the backing object for some or all of | |
447 | * the pages | |
448 | * 0 - dispatched a read on all pages | |
449 | * | |
450 | * end_io_func() will be called for each page read from the cache as it is | |
451 | * finishes being read | |
452 | * | |
453 | * any pages for which a read is dispatched will be removed from pages and | |
454 | * nr_pages | |
455 | */ | |
456 | int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie, | |
457 | struct address_space *mapping, | |
458 | struct list_head *pages, | |
459 | unsigned *nr_pages, | |
460 | fscache_rw_complete_t end_io_func, | |
461 | void *context, | |
462 | gfp_t gfp) | |
463 | { | |
b5108822 DH |
464 | struct fscache_retrieval *op; |
465 | struct fscache_object *object; | |
466 | int ret; | |
467 | ||
468 | _enter("%p,,%d,,,", cookie, *nr_pages); | |
469 | ||
470 | fscache_stat(&fscache_n_retrievals); | |
471 | ||
472 | if (hlist_empty(&cookie->backing_objects)) | |
473 | goto nobufs; | |
474 | ||
475 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
476 | ASSERTCMP(*nr_pages, >, 0); | |
477 | ASSERT(!list_empty(pages)); | |
478 | ||
479 | if (fscache_wait_for_deferred_lookup(cookie) < 0) | |
480 | return -ERESTARTSYS; | |
481 | ||
482 | op = fscache_alloc_retrieval(mapping, end_io_func, context); | |
483 | if (!op) | |
484 | return -ENOMEM; | |
485 | ||
486 | spin_lock(&cookie->lock); | |
487 | ||
488 | if (hlist_empty(&cookie->backing_objects)) | |
489 | goto nobufs_unlock; | |
490 | object = hlist_entry(cookie->backing_objects.first, | |
491 | struct fscache_object, cookie_link); | |
492 | ||
4fbf4291 DH |
493 | atomic_inc(&object->n_reads); |
494 | set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags); | |
495 | ||
b5108822 DH |
496 | if (fscache_submit_op(object, &op->op) < 0) |
497 | goto nobufs_unlock; | |
498 | spin_unlock(&cookie->lock); | |
499 | ||
500 | fscache_stat(&fscache_n_retrieval_ops); | |
501 | ||
502 | /* pin the netfs read context in case we need to do the actual netfs | |
503 | * read because we've encountered a cache read failure */ | |
504 | fscache_get_context(object->cookie, op->context); | |
505 | ||
506 | /* we wait for the operation to become active, and then process it | |
507 | * *here*, in this thread, and not in the thread pool */ | |
60d543ca DH |
508 | ret = fscache_wait_for_retrieval_activation( |
509 | object, op, | |
510 | __fscache_stat(&fscache_n_retrieval_op_waits), | |
511 | __fscache_stat(&fscache_n_retrievals_object_dead)); | |
512 | if (ret < 0) | |
513 | goto error; | |
b5108822 DH |
514 | |
515 | /* ask the cache to honour the operation */ | |
52bd75fd DH |
516 | if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { |
517 | fscache_stat(&fscache_n_cop_allocate_pages); | |
518 | ret = object->cache->ops->allocate_pages( | |
519 | op, pages, nr_pages, gfp); | |
520 | fscache_stat_d(&fscache_n_cop_allocate_pages); | |
521 | } else { | |
522 | fscache_stat(&fscache_n_cop_read_or_alloc_pages); | |
523 | ret = object->cache->ops->read_or_alloc_pages( | |
524 | op, pages, nr_pages, gfp); | |
525 | fscache_stat_d(&fscache_n_cop_read_or_alloc_pages); | |
526 | } | |
b5108822 | 527 | |
5753c441 | 528 | error: |
b5108822 DH |
529 | if (ret == -ENOMEM) |
530 | fscache_stat(&fscache_n_retrievals_nomem); | |
531 | else if (ret == -ERESTARTSYS) | |
532 | fscache_stat(&fscache_n_retrievals_intr); | |
533 | else if (ret == -ENODATA) | |
534 | fscache_stat(&fscache_n_retrievals_nodata); | |
535 | else if (ret < 0) | |
536 | fscache_stat(&fscache_n_retrievals_nobufs); | |
537 | else | |
538 | fscache_stat(&fscache_n_retrievals_ok); | |
539 | ||
540 | fscache_put_retrieval(op); | |
541 | _leave(" = %d", ret); | |
542 | return ret; | |
543 | ||
544 | nobufs_unlock: | |
545 | spin_unlock(&cookie->lock); | |
546 | kfree(op); | |
547 | nobufs: | |
548 | fscache_stat(&fscache_n_retrievals_nobufs); | |
549 | _leave(" = -ENOBUFS"); | |
550 | return -ENOBUFS; | |
551 | } | |
552 | EXPORT_SYMBOL(__fscache_read_or_alloc_pages); | |
553 | ||
554 | /* | |
555 | * allocate a block in the cache on which to store a page | |
556 | * - we return: | |
557 | * -ENOMEM - out of memory, nothing done | |
558 | * -ERESTARTSYS - interrupted | |
559 | * -ENOBUFS - no backing object available in which to cache the block | |
560 | * 0 - block allocated | |
561 | */ | |
562 | int __fscache_alloc_page(struct fscache_cookie *cookie, | |
563 | struct page *page, | |
564 | gfp_t gfp) | |
565 | { | |
566 | struct fscache_retrieval *op; | |
567 | struct fscache_object *object; | |
568 | int ret; | |
569 | ||
570 | _enter("%p,%p,,,", cookie, page); | |
571 | ||
572 | fscache_stat(&fscache_n_allocs); | |
573 | ||
574 | if (hlist_empty(&cookie->backing_objects)) | |
575 | goto nobufs; | |
576 | ||
577 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
578 | ASSERTCMP(page, !=, NULL); | |
579 | ||
580 | if (fscache_wait_for_deferred_lookup(cookie) < 0) | |
581 | return -ERESTARTSYS; | |
582 | ||
583 | op = fscache_alloc_retrieval(page->mapping, NULL, NULL); | |
584 | if (!op) | |
585 | return -ENOMEM; | |
586 | ||
587 | spin_lock(&cookie->lock); | |
588 | ||
589 | if (hlist_empty(&cookie->backing_objects)) | |
590 | goto nobufs_unlock; | |
591 | object = hlist_entry(cookie->backing_objects.first, | |
592 | struct fscache_object, cookie_link); | |
593 | ||
594 | if (fscache_submit_op(object, &op->op) < 0) | |
595 | goto nobufs_unlock; | |
596 | spin_unlock(&cookie->lock); | |
597 | ||
598 | fscache_stat(&fscache_n_alloc_ops); | |
599 | ||
60d543ca DH |
600 | ret = fscache_wait_for_retrieval_activation( |
601 | object, op, | |
602 | __fscache_stat(&fscache_n_alloc_op_waits), | |
603 | __fscache_stat(&fscache_n_allocs_object_dead)); | |
604 | if (ret < 0) | |
605 | goto error; | |
b5108822 DH |
606 | |
607 | /* ask the cache to honour the operation */ | |
52bd75fd | 608 | fscache_stat(&fscache_n_cop_allocate_page); |
b5108822 | 609 | ret = object->cache->ops->allocate_page(op, page, gfp); |
52bd75fd | 610 | fscache_stat_d(&fscache_n_cop_allocate_page); |
b5108822 | 611 | |
5753c441 DH |
612 | error: |
613 | if (ret == -ERESTARTSYS) | |
614 | fscache_stat(&fscache_n_allocs_intr); | |
615 | else if (ret < 0) | |
b5108822 DH |
616 | fscache_stat(&fscache_n_allocs_nobufs); |
617 | else | |
618 | fscache_stat(&fscache_n_allocs_ok); | |
619 | ||
620 | fscache_put_retrieval(op); | |
621 | _leave(" = %d", ret); | |
622 | return ret; | |
623 | ||
624 | nobufs_unlock: | |
625 | spin_unlock(&cookie->lock); | |
626 | kfree(op); | |
627 | nobufs: | |
628 | fscache_stat(&fscache_n_allocs_nobufs); | |
629 | _leave(" = -ENOBUFS"); | |
630 | return -ENOBUFS; | |
631 | } | |
632 | EXPORT_SYMBOL(__fscache_alloc_page); | |
633 | ||
634 | /* | |
635 | * release a write op reference | |
636 | */ | |
637 | static void fscache_release_write_op(struct fscache_operation *_op) | |
638 | { | |
639 | _enter("{OP%x}", _op->debug_id); | |
640 | } | |
641 | ||
642 | /* | |
643 | * perform the background storage of a page into the cache | |
644 | */ | |
645 | static void fscache_write_op(struct fscache_operation *_op) | |
646 | { | |
647 | struct fscache_storage *op = | |
648 | container_of(_op, struct fscache_storage, op); | |
649 | struct fscache_object *object = op->op.object; | |
1bccf513 | 650 | struct fscache_cookie *cookie; |
b5108822 DH |
651 | struct page *page; |
652 | unsigned n; | |
653 | void *results[1]; | |
654 | int ret; | |
655 | ||
656 | _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage)); | |
657 | ||
b5108822 | 658 | spin_lock(&object->lock); |
1bccf513 | 659 | cookie = object->cookie; |
b5108822 | 660 | |
1bccf513 | 661 | if (!fscache_object_is_active(object) || !cookie) { |
b5108822 | 662 | spin_unlock(&object->lock); |
b5108822 DH |
663 | _leave(""); |
664 | return; | |
665 | } | |
666 | ||
1bccf513 DH |
667 | spin_lock(&cookie->stores_lock); |
668 | ||
b5108822 DH |
669 | fscache_stat(&fscache_n_store_calls); |
670 | ||
671 | /* find a page to store */ | |
672 | page = NULL; | |
673 | n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1, | |
674 | FSCACHE_COOKIE_PENDING_TAG); | |
675 | if (n != 1) | |
676 | goto superseded; | |
677 | page = results[0]; | |
678 | _debug("gang %d [%lx]", n, page->index); | |
1bccf513 DH |
679 | if (page->index > op->store_limit) { |
680 | fscache_stat(&fscache_n_store_pages_over_limit); | |
b5108822 | 681 | goto superseded; |
1bccf513 | 682 | } |
b5108822 | 683 | |
08a66859 DC |
684 | radix_tree_tag_set(&cookie->stores, page->index, |
685 | FSCACHE_COOKIE_STORING_TAG); | |
686 | radix_tree_tag_clear(&cookie->stores, page->index, | |
687 | FSCACHE_COOKIE_PENDING_TAG); | |
b5108822 | 688 | |
1bccf513 | 689 | spin_unlock(&cookie->stores_lock); |
b5108822 | 690 | spin_unlock(&object->lock); |
b5108822 | 691 | |
08a66859 DC |
692 | fscache_stat(&fscache_n_store_pages); |
693 | fscache_stat(&fscache_n_cop_write_page); | |
694 | ret = object->cache->ops->write_page(op, page); | |
695 | fscache_stat_d(&fscache_n_cop_write_page); | |
08a66859 DC |
696 | fscache_end_page_write(object, page); |
697 | if (ret < 0) { | |
08a66859 DC |
698 | fscache_abort_object(object); |
699 | } else { | |
700 | fscache_enqueue_operation(&op->op); | |
b5108822 DH |
701 | } |
702 | ||
703 | _leave(""); | |
704 | return; | |
705 | ||
706 | superseded: | |
707 | /* this writer is going away and there aren't any more things to | |
708 | * write */ | |
709 | _debug("cease"); | |
1bccf513 | 710 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
711 | clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags); |
712 | spin_unlock(&object->lock); | |
b5108822 DH |
713 | _leave(""); |
714 | } | |
715 | ||
716 | /* | |
717 | * request a page be stored in the cache | |
718 | * - returns: | |
719 | * -ENOMEM - out of memory, nothing done | |
720 | * -ENOBUFS - no backing object available in which to cache the page | |
721 | * 0 - dispatched a write - it'll call end_io_func() when finished | |
722 | * | |
723 | * if the cookie still has a backing object at this point, that object can be | |
724 | * in one of a few states with respect to storage processing: | |
725 | * | |
726 | * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is | |
727 | * set) | |
728 | * | |
729 | * (a) no writes yet (set FSCACHE_COOKIE_PENDING_FILL and queue deferred | |
730 | * fill op) | |
731 | * | |
732 | * (b) writes deferred till post-creation (mark page for writing and | |
733 | * return immediately) | |
734 | * | |
735 | * (2) negative lookup, object created, initial fill being made from netfs | |
736 | * (FSCACHE_COOKIE_INITIAL_FILL is set) | |
737 | * | |
738 | * (a) fill point not yet reached this page (mark page for writing and | |
739 | * return) | |
740 | * | |
741 | * (b) fill point passed this page (queue op to store this page) | |
742 | * | |
743 | * (3) object extant (queue op to store this page) | |
744 | * | |
745 | * any other state is invalid | |
746 | */ | |
747 | int __fscache_write_page(struct fscache_cookie *cookie, | |
748 | struct page *page, | |
749 | gfp_t gfp) | |
750 | { | |
751 | struct fscache_storage *op; | |
752 | struct fscache_object *object; | |
753 | int ret; | |
754 | ||
755 | _enter("%p,%x,", cookie, (u32) page->flags); | |
756 | ||
757 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
758 | ASSERT(PageFsCache(page)); | |
759 | ||
760 | fscache_stat(&fscache_n_stores); | |
761 | ||
762 | op = kzalloc(sizeof(*op), GFP_NOIO); | |
763 | if (!op) | |
764 | goto nomem; | |
765 | ||
8af7c124 TH |
766 | fscache_operation_init(&op->op, fscache_write_op, |
767 | fscache_release_write_op); | |
768 | op->op.flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_WAITING); | |
b5108822 DH |
769 | |
770 | ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM); | |
771 | if (ret < 0) | |
772 | goto nomem_free; | |
773 | ||
774 | ret = -ENOBUFS; | |
775 | spin_lock(&cookie->lock); | |
776 | ||
777 | if (hlist_empty(&cookie->backing_objects)) | |
778 | goto nobufs; | |
779 | object = hlist_entry(cookie->backing_objects.first, | |
780 | struct fscache_object, cookie_link); | |
781 | if (test_bit(FSCACHE_IOERROR, &object->cache->flags)) | |
782 | goto nobufs; | |
783 | ||
784 | /* add the page to the pending-storage radix tree on the backing | |
785 | * object */ | |
786 | spin_lock(&object->lock); | |
1bccf513 | 787 | spin_lock(&cookie->stores_lock); |
b5108822 DH |
788 | |
789 | _debug("store limit %llx", (unsigned long long) object->store_limit); | |
790 | ||
791 | ret = radix_tree_insert(&cookie->stores, page->index, page); | |
792 | if (ret < 0) { | |
793 | if (ret == -EEXIST) | |
794 | goto already_queued; | |
795 | _debug("insert failed %d", ret); | |
796 | goto nobufs_unlock_obj; | |
797 | } | |
798 | ||
799 | radix_tree_tag_set(&cookie->stores, page->index, | |
800 | FSCACHE_COOKIE_PENDING_TAG); | |
801 | page_cache_get(page); | |
802 | ||
803 | /* we only want one writer at a time, but we do need to queue new | |
804 | * writers after exclusive ops */ | |
805 | if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags)) | |
806 | goto already_pending; | |
807 | ||
1bccf513 | 808 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
809 | spin_unlock(&object->lock); |
810 | ||
811 | op->op.debug_id = atomic_inc_return(&fscache_op_debug_id); | |
812 | op->store_limit = object->store_limit; | |
813 | ||
814 | if (fscache_submit_op(object, &op->op) < 0) | |
815 | goto submit_failed; | |
816 | ||
817 | spin_unlock(&cookie->lock); | |
818 | radix_tree_preload_end(); | |
819 | fscache_stat(&fscache_n_store_ops); | |
820 | fscache_stat(&fscache_n_stores_ok); | |
821 | ||
8af7c124 | 822 | /* the work queue now carries its own ref on the object */ |
b5108822 DH |
823 | fscache_put_operation(&op->op); |
824 | _leave(" = 0"); | |
825 | return 0; | |
826 | ||
827 | already_queued: | |
828 | fscache_stat(&fscache_n_stores_again); | |
829 | already_pending: | |
1bccf513 | 830 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
831 | spin_unlock(&object->lock); |
832 | spin_unlock(&cookie->lock); | |
833 | radix_tree_preload_end(); | |
834 | kfree(op); | |
835 | fscache_stat(&fscache_n_stores_ok); | |
836 | _leave(" = 0"); | |
837 | return 0; | |
838 | ||
839 | submit_failed: | |
1bccf513 | 840 | spin_lock(&cookie->stores_lock); |
b5108822 | 841 | radix_tree_delete(&cookie->stores, page->index); |
1bccf513 | 842 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
843 | page_cache_release(page); |
844 | ret = -ENOBUFS; | |
845 | goto nobufs; | |
846 | ||
847 | nobufs_unlock_obj: | |
1147d0f9 | 848 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
849 | spin_unlock(&object->lock); |
850 | nobufs: | |
851 | spin_unlock(&cookie->lock); | |
852 | radix_tree_preload_end(); | |
853 | kfree(op); | |
854 | fscache_stat(&fscache_n_stores_nobufs); | |
855 | _leave(" = -ENOBUFS"); | |
856 | return -ENOBUFS; | |
857 | ||
858 | nomem_free: | |
859 | kfree(op); | |
860 | nomem: | |
861 | fscache_stat(&fscache_n_stores_oom); | |
862 | _leave(" = -ENOMEM"); | |
863 | return -ENOMEM; | |
864 | } | |
865 | EXPORT_SYMBOL(__fscache_write_page); | |
866 | ||
867 | /* | |
868 | * remove a page from the cache | |
869 | */ | |
870 | void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page) | |
871 | { | |
872 | struct fscache_object *object; | |
873 | ||
874 | _enter(",%p", page); | |
875 | ||
876 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
877 | ASSERTCMP(page, !=, NULL); | |
878 | ||
879 | fscache_stat(&fscache_n_uncaches); | |
880 | ||
881 | /* cache withdrawal may beat us to it */ | |
882 | if (!PageFsCache(page)) | |
883 | goto done; | |
884 | ||
885 | /* get the object */ | |
886 | spin_lock(&cookie->lock); | |
887 | ||
888 | if (hlist_empty(&cookie->backing_objects)) { | |
889 | ClearPageFsCache(page); | |
890 | goto done_unlock; | |
891 | } | |
892 | ||
893 | object = hlist_entry(cookie->backing_objects.first, | |
894 | struct fscache_object, cookie_link); | |
895 | ||
896 | /* there might now be stuff on disk we could read */ | |
897 | clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); | |
898 | ||
899 | /* only invoke the cache backend if we managed to mark the page | |
900 | * uncached here; this deals with synchronisation vs withdrawal */ | |
901 | if (TestClearPageFsCache(page) && | |
902 | object->cache->ops->uncache_page) { | |
903 | /* the cache backend releases the cookie lock */ | |
52bd75fd | 904 | fscache_stat(&fscache_n_cop_uncache_page); |
b5108822 | 905 | object->cache->ops->uncache_page(object, page); |
52bd75fd | 906 | fscache_stat_d(&fscache_n_cop_uncache_page); |
b5108822 DH |
907 | goto done; |
908 | } | |
909 | ||
910 | done_unlock: | |
911 | spin_unlock(&cookie->lock); | |
912 | done: | |
913 | _leave(""); | |
914 | } | |
915 | EXPORT_SYMBOL(__fscache_uncache_page); | |
916 | ||
917 | /** | |
918 | * fscache_mark_pages_cached - Mark pages as being cached | |
919 | * @op: The retrieval op pages are being marked for | |
920 | * @pagevec: The pages to be marked | |
921 | * | |
922 | * Mark a bunch of netfs pages as being cached. After this is called, | |
923 | * the netfs must call fscache_uncache_page() to remove the mark. | |
924 | */ | |
925 | void fscache_mark_pages_cached(struct fscache_retrieval *op, | |
926 | struct pagevec *pagevec) | |
927 | { | |
928 | struct fscache_cookie *cookie = op->op.object->cookie; | |
929 | unsigned long loop; | |
930 | ||
931 | #ifdef CONFIG_FSCACHE_STATS | |
932 | atomic_add(pagevec->nr, &fscache_n_marks); | |
933 | #endif | |
934 | ||
935 | for (loop = 0; loop < pagevec->nr; loop++) { | |
936 | struct page *page = pagevec->pages[loop]; | |
937 | ||
938 | _debug("- mark %p{%lx}", page, page->index); | |
939 | if (TestSetPageFsCache(page)) { | |
940 | static bool once_only; | |
941 | if (!once_only) { | |
942 | once_only = true; | |
943 | printk(KERN_WARNING "FS-Cache:" | |
944 | " Cookie type %s marked page %lx" | |
945 | " multiple times\n", | |
946 | cookie->def->name, page->index); | |
947 | } | |
948 | } | |
949 | } | |
950 | ||
951 | if (cookie->def->mark_pages_cached) | |
952 | cookie->def->mark_pages_cached(cookie->netfs_data, | |
953 | op->mapping, pagevec); | |
954 | pagevec_reinit(pagevec); | |
955 | } | |
956 | EXPORT_SYMBOL(fscache_mark_pages_cached); | |
c902ce1b DH |
957 | |
958 | /* | |
959 | * Uncache all the pages in an inode that are marked PG_fscache, assuming them | |
960 | * to be associated with the given cookie. | |
961 | */ | |
962 | void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie, | |
963 | struct inode *inode) | |
964 | { | |
965 | struct address_space *mapping = inode->i_mapping; | |
966 | struct pagevec pvec; | |
967 | pgoff_t next; | |
968 | int i; | |
969 | ||
970 | _enter("%p,%p", cookie, inode); | |
971 | ||
972 | if (!mapping || mapping->nrpages == 0) { | |
973 | _leave(" [no pages]"); | |
974 | return; | |
975 | } | |
976 | ||
977 | pagevec_init(&pvec, 0); | |
978 | next = 0; | |
b307d465 JB |
979 | do { |
980 | if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) | |
981 | break; | |
c902ce1b DH |
982 | for (i = 0; i < pagevec_count(&pvec); i++) { |
983 | struct page *page = pvec.pages[i]; | |
b307d465 | 984 | next = page->index; |
c902ce1b DH |
985 | if (PageFsCache(page)) { |
986 | __fscache_wait_on_page_write(cookie, page); | |
987 | __fscache_uncache_page(cookie, page); | |
988 | } | |
989 | } | |
990 | pagevec_release(&pvec); | |
991 | cond_resched(); | |
b307d465 | 992 | } while (++next); |
c902ce1b DH |
993 | |
994 | _leave(""); | |
995 | } | |
996 | EXPORT_SYMBOL(__fscache_uncache_all_inode_pages); |