Commit | Line | Data |
---|---|---|
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 DH |
157 | if (fscache_object_is_active(object)) { |
158 | fscache_set_op_state(op, "CallFS"); | |
52bd75fd | 159 | fscache_stat(&fscache_n_cop_attr_changed); |
440f0aff | 160 | ret = object->cache->ops->attr_changed(object); |
52bd75fd | 161 | fscache_stat_d(&fscache_n_cop_attr_changed); |
440f0aff DH |
162 | fscache_set_op_state(op, "Done"); |
163 | if (ret < 0) | |
164 | fscache_abort_object(object); | |
165 | } | |
b5108822 DH |
166 | |
167 | _leave(""); | |
168 | } | |
169 | ||
170 | /* | |
171 | * notification that the attributes on an object have changed | |
172 | */ | |
173 | int __fscache_attr_changed(struct fscache_cookie *cookie) | |
174 | { | |
175 | struct fscache_operation *op; | |
176 | struct fscache_object *object; | |
177 | ||
178 | _enter("%p", cookie); | |
179 | ||
180 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
181 | ||
182 | fscache_stat(&fscache_n_attr_changed); | |
183 | ||
184 | op = kzalloc(sizeof(*op), GFP_KERNEL); | |
185 | if (!op) { | |
186 | fscache_stat(&fscache_n_attr_changed_nomem); | |
187 | _leave(" = -ENOMEM"); | |
188 | return -ENOMEM; | |
189 | } | |
190 | ||
8af7c124 TH |
191 | fscache_operation_init(op, fscache_attr_changed_op, NULL); |
192 | op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE); | |
440f0aff | 193 | fscache_set_op_name(op, "Attr"); |
b5108822 DH |
194 | |
195 | spin_lock(&cookie->lock); | |
196 | ||
197 | if (hlist_empty(&cookie->backing_objects)) | |
198 | goto nobufs; | |
199 | object = hlist_entry(cookie->backing_objects.first, | |
200 | struct fscache_object, cookie_link); | |
201 | ||
202 | if (fscache_submit_exclusive_op(object, op) < 0) | |
203 | goto nobufs; | |
204 | spin_unlock(&cookie->lock); | |
205 | fscache_stat(&fscache_n_attr_changed_ok); | |
206 | fscache_put_operation(op); | |
207 | _leave(" = 0"); | |
208 | return 0; | |
209 | ||
210 | nobufs: | |
211 | spin_unlock(&cookie->lock); | |
212 | kfree(op); | |
213 | fscache_stat(&fscache_n_attr_changed_nobufs); | |
214 | _leave(" = %d", -ENOBUFS); | |
215 | return -ENOBUFS; | |
216 | } | |
217 | EXPORT_SYMBOL(__fscache_attr_changed); | |
218 | ||
b5108822 DH |
219 | /* |
220 | * release a retrieval op reference | |
221 | */ | |
222 | static void fscache_release_retrieval_op(struct fscache_operation *_op) | |
223 | { | |
224 | struct fscache_retrieval *op = | |
225 | container_of(_op, struct fscache_retrieval, op); | |
226 | ||
227 | _enter("{OP%x}", op->op.debug_id); | |
228 | ||
229 | fscache_hist(fscache_retrieval_histogram, op->start_time); | |
230 | if (op->context) | |
231 | fscache_put_context(op->op.object->cookie, op->context); | |
232 | ||
233 | _leave(""); | |
234 | } | |
235 | ||
236 | /* | |
237 | * allocate a retrieval op | |
238 | */ | |
239 | static struct fscache_retrieval *fscache_alloc_retrieval( | |
240 | struct address_space *mapping, | |
241 | fscache_rw_complete_t end_io_func, | |
242 | void *context) | |
243 | { | |
244 | struct fscache_retrieval *op; | |
245 | ||
246 | /* allocate a retrieval operation and attempt to submit it */ | |
247 | op = kzalloc(sizeof(*op), GFP_NOIO); | |
248 | if (!op) { | |
249 | fscache_stat(&fscache_n_retrievals_nomem); | |
250 | return NULL; | |
251 | } | |
252 | ||
8af7c124 | 253 | fscache_operation_init(&op->op, NULL, fscache_release_retrieval_op); |
b5108822 DH |
254 | op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING); |
255 | op->mapping = mapping; | |
256 | op->end_io_func = end_io_func; | |
257 | op->context = context; | |
258 | op->start_time = jiffies; | |
b5108822 | 259 | INIT_LIST_HEAD(&op->to_do); |
440f0aff | 260 | fscache_set_op_name(&op->op, "Retr"); |
b5108822 DH |
261 | return op; |
262 | } | |
263 | ||
264 | /* | |
265 | * wait for a deferred lookup to complete | |
266 | */ | |
267 | static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie) | |
268 | { | |
269 | unsigned long jif; | |
270 | ||
271 | _enter(""); | |
272 | ||
273 | if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) { | |
274 | _leave(" = 0 [imm]"); | |
275 | return 0; | |
276 | } | |
277 | ||
278 | fscache_stat(&fscache_n_retrievals_wait); | |
279 | ||
280 | jif = jiffies; | |
281 | if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP, | |
282 | fscache_wait_bit_interruptible, | |
283 | TASK_INTERRUPTIBLE) != 0) { | |
284 | fscache_stat(&fscache_n_retrievals_intr); | |
285 | _leave(" = -ERESTARTSYS"); | |
286 | return -ERESTARTSYS; | |
287 | } | |
288 | ||
289 | ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)); | |
290 | ||
291 | smp_rmb(); | |
292 | fscache_hist(fscache_retrieval_delay_histogram, jif); | |
293 | _leave(" = 0 [dly]"); | |
294 | return 0; | |
295 | } | |
296 | ||
60d543ca DH |
297 | /* |
298 | * wait for an object to become active (or dead) | |
299 | */ | |
300 | static int fscache_wait_for_retrieval_activation(struct fscache_object *object, | |
301 | struct fscache_retrieval *op, | |
302 | atomic_t *stat_op_waits, | |
303 | atomic_t *stat_object_dead) | |
304 | { | |
305 | int ret; | |
306 | ||
307 | if (!test_bit(FSCACHE_OP_WAITING, &op->op.flags)) | |
308 | goto check_if_dead; | |
309 | ||
310 | _debug(">>> WT"); | |
311 | fscache_stat(stat_op_waits); | |
312 | if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, | |
313 | fscache_wait_bit_interruptible, | |
314 | TASK_INTERRUPTIBLE) < 0) { | |
315 | ret = fscache_cancel_op(&op->op); | |
316 | if (ret == 0) | |
317 | return -ERESTARTSYS; | |
318 | ||
319 | /* it's been removed from the pending queue by another party, | |
320 | * so we should get to run shortly */ | |
321 | wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, | |
322 | fscache_wait_bit, TASK_UNINTERRUPTIBLE); | |
323 | } | |
324 | _debug("<<< GO"); | |
325 | ||
326 | check_if_dead: | |
327 | if (unlikely(fscache_object_is_dead(object))) { | |
328 | fscache_stat(stat_object_dead); | |
329 | return -ENOBUFS; | |
330 | } | |
331 | return 0; | |
332 | } | |
333 | ||
b5108822 DH |
334 | /* |
335 | * read a page from the cache or allocate a block in which to store it | |
336 | * - we return: | |
337 | * -ENOMEM - out of memory, nothing done | |
338 | * -ERESTARTSYS - interrupted | |
339 | * -ENOBUFS - no backing object available in which to cache the block | |
340 | * -ENODATA - no data available in the backing object for this block | |
341 | * 0 - dispatched a read - it'll call end_io_func() when finished | |
342 | */ | |
343 | int __fscache_read_or_alloc_page(struct fscache_cookie *cookie, | |
344 | struct page *page, | |
345 | fscache_rw_complete_t end_io_func, | |
346 | void *context, | |
347 | gfp_t gfp) | |
348 | { | |
349 | struct fscache_retrieval *op; | |
350 | struct fscache_object *object; | |
351 | int ret; | |
352 | ||
353 | _enter("%p,%p,,,", cookie, page); | |
354 | ||
355 | fscache_stat(&fscache_n_retrievals); | |
356 | ||
357 | if (hlist_empty(&cookie->backing_objects)) | |
358 | goto nobufs; | |
359 | ||
360 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
361 | ASSERTCMP(page, !=, NULL); | |
362 | ||
363 | if (fscache_wait_for_deferred_lookup(cookie) < 0) | |
364 | return -ERESTARTSYS; | |
365 | ||
366 | op = fscache_alloc_retrieval(page->mapping, end_io_func, context); | |
367 | if (!op) { | |
368 | _leave(" = -ENOMEM"); | |
369 | return -ENOMEM; | |
370 | } | |
440f0aff | 371 | fscache_set_op_name(&op->op, "RetrRA1"); |
b5108822 DH |
372 | |
373 | spin_lock(&cookie->lock); | |
374 | ||
375 | if (hlist_empty(&cookie->backing_objects)) | |
376 | goto nobufs_unlock; | |
377 | object = hlist_entry(cookie->backing_objects.first, | |
378 | struct fscache_object, cookie_link); | |
379 | ||
380 | ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP); | |
381 | ||
4fbf4291 DH |
382 | atomic_inc(&object->n_reads); |
383 | set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags); | |
384 | ||
b5108822 DH |
385 | if (fscache_submit_op(object, &op->op) < 0) |
386 | goto nobufs_unlock; | |
387 | spin_unlock(&cookie->lock); | |
388 | ||
389 | fscache_stat(&fscache_n_retrieval_ops); | |
390 | ||
391 | /* pin the netfs read context in case we need to do the actual netfs | |
392 | * read because we've encountered a cache read failure */ | |
393 | fscache_get_context(object->cookie, op->context); | |
394 | ||
395 | /* we wait for the operation to become active, and then process it | |
396 | * *here*, in this thread, and not in the thread pool */ | |
60d543ca DH |
397 | ret = fscache_wait_for_retrieval_activation( |
398 | object, op, | |
399 | __fscache_stat(&fscache_n_retrieval_op_waits), | |
400 | __fscache_stat(&fscache_n_retrievals_object_dead)); | |
401 | if (ret < 0) | |
402 | goto error; | |
b5108822 DH |
403 | |
404 | /* ask the cache to honour the operation */ | |
405 | if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { | |
52bd75fd | 406 | fscache_stat(&fscache_n_cop_allocate_page); |
b5108822 | 407 | ret = object->cache->ops->allocate_page(op, page, gfp); |
52bd75fd | 408 | fscache_stat_d(&fscache_n_cop_allocate_page); |
b5108822 DH |
409 | if (ret == 0) |
410 | ret = -ENODATA; | |
411 | } else { | |
52bd75fd | 412 | fscache_stat(&fscache_n_cop_read_or_alloc_page); |
b5108822 | 413 | ret = object->cache->ops->read_or_alloc_page(op, page, gfp); |
52bd75fd | 414 | fscache_stat_d(&fscache_n_cop_read_or_alloc_page); |
b5108822 DH |
415 | } |
416 | ||
5753c441 | 417 | error: |
b5108822 DH |
418 | if (ret == -ENOMEM) |
419 | fscache_stat(&fscache_n_retrievals_nomem); | |
420 | else if (ret == -ERESTARTSYS) | |
421 | fscache_stat(&fscache_n_retrievals_intr); | |
422 | else if (ret == -ENODATA) | |
423 | fscache_stat(&fscache_n_retrievals_nodata); | |
424 | else if (ret < 0) | |
425 | fscache_stat(&fscache_n_retrievals_nobufs); | |
426 | else | |
427 | fscache_stat(&fscache_n_retrievals_ok); | |
428 | ||
429 | fscache_put_retrieval(op); | |
430 | _leave(" = %d", ret); | |
431 | return ret; | |
432 | ||
433 | nobufs_unlock: | |
434 | spin_unlock(&cookie->lock); | |
435 | kfree(op); | |
436 | nobufs: | |
437 | fscache_stat(&fscache_n_retrievals_nobufs); | |
438 | _leave(" = -ENOBUFS"); | |
439 | return -ENOBUFS; | |
440 | } | |
441 | EXPORT_SYMBOL(__fscache_read_or_alloc_page); | |
442 | ||
443 | /* | |
444 | * read a list of page from the cache or allocate a block in which to store | |
445 | * them | |
446 | * - we return: | |
447 | * -ENOMEM - out of memory, some pages may be being read | |
448 | * -ERESTARTSYS - interrupted, some pages may be being read | |
449 | * -ENOBUFS - no backing object or space available in which to cache any | |
450 | * pages not being read | |
451 | * -ENODATA - no data available in the backing object for some or all of | |
452 | * the pages | |
453 | * 0 - dispatched a read on all pages | |
454 | * | |
455 | * end_io_func() will be called for each page read from the cache as it is | |
456 | * finishes being read | |
457 | * | |
458 | * any pages for which a read is dispatched will be removed from pages and | |
459 | * nr_pages | |
460 | */ | |
461 | int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie, | |
462 | struct address_space *mapping, | |
463 | struct list_head *pages, | |
464 | unsigned *nr_pages, | |
465 | fscache_rw_complete_t end_io_func, | |
466 | void *context, | |
467 | gfp_t gfp) | |
468 | { | |
b5108822 DH |
469 | struct fscache_retrieval *op; |
470 | struct fscache_object *object; | |
471 | int ret; | |
472 | ||
473 | _enter("%p,,%d,,,", cookie, *nr_pages); | |
474 | ||
475 | fscache_stat(&fscache_n_retrievals); | |
476 | ||
477 | if (hlist_empty(&cookie->backing_objects)) | |
478 | goto nobufs; | |
479 | ||
480 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
481 | ASSERTCMP(*nr_pages, >, 0); | |
482 | ASSERT(!list_empty(pages)); | |
483 | ||
484 | if (fscache_wait_for_deferred_lookup(cookie) < 0) | |
485 | return -ERESTARTSYS; | |
486 | ||
487 | op = fscache_alloc_retrieval(mapping, end_io_func, context); | |
488 | if (!op) | |
489 | return -ENOMEM; | |
440f0aff | 490 | fscache_set_op_name(&op->op, "RetrRAN"); |
b5108822 DH |
491 | |
492 | spin_lock(&cookie->lock); | |
493 | ||
494 | if (hlist_empty(&cookie->backing_objects)) | |
495 | goto nobufs_unlock; | |
496 | object = hlist_entry(cookie->backing_objects.first, | |
497 | struct fscache_object, cookie_link); | |
498 | ||
4fbf4291 DH |
499 | atomic_inc(&object->n_reads); |
500 | set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags); | |
501 | ||
b5108822 DH |
502 | if (fscache_submit_op(object, &op->op) < 0) |
503 | goto nobufs_unlock; | |
504 | spin_unlock(&cookie->lock); | |
505 | ||
506 | fscache_stat(&fscache_n_retrieval_ops); | |
507 | ||
508 | /* pin the netfs read context in case we need to do the actual netfs | |
509 | * read because we've encountered a cache read failure */ | |
510 | fscache_get_context(object->cookie, op->context); | |
511 | ||
512 | /* we wait for the operation to become active, and then process it | |
513 | * *here*, in this thread, and not in the thread pool */ | |
60d543ca DH |
514 | ret = fscache_wait_for_retrieval_activation( |
515 | object, op, | |
516 | __fscache_stat(&fscache_n_retrieval_op_waits), | |
517 | __fscache_stat(&fscache_n_retrievals_object_dead)); | |
518 | if (ret < 0) | |
519 | goto error; | |
b5108822 DH |
520 | |
521 | /* ask the cache to honour the operation */ | |
52bd75fd DH |
522 | if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { |
523 | fscache_stat(&fscache_n_cop_allocate_pages); | |
524 | ret = object->cache->ops->allocate_pages( | |
525 | op, pages, nr_pages, gfp); | |
526 | fscache_stat_d(&fscache_n_cop_allocate_pages); | |
527 | } else { | |
528 | fscache_stat(&fscache_n_cop_read_or_alloc_pages); | |
529 | ret = object->cache->ops->read_or_alloc_pages( | |
530 | op, pages, nr_pages, gfp); | |
531 | fscache_stat_d(&fscache_n_cop_read_or_alloc_pages); | |
532 | } | |
b5108822 | 533 | |
5753c441 | 534 | error: |
b5108822 DH |
535 | if (ret == -ENOMEM) |
536 | fscache_stat(&fscache_n_retrievals_nomem); | |
537 | else if (ret == -ERESTARTSYS) | |
538 | fscache_stat(&fscache_n_retrievals_intr); | |
539 | else if (ret == -ENODATA) | |
540 | fscache_stat(&fscache_n_retrievals_nodata); | |
541 | else if (ret < 0) | |
542 | fscache_stat(&fscache_n_retrievals_nobufs); | |
543 | else | |
544 | fscache_stat(&fscache_n_retrievals_ok); | |
545 | ||
546 | fscache_put_retrieval(op); | |
547 | _leave(" = %d", ret); | |
548 | return ret; | |
549 | ||
550 | nobufs_unlock: | |
551 | spin_unlock(&cookie->lock); | |
552 | kfree(op); | |
553 | nobufs: | |
554 | fscache_stat(&fscache_n_retrievals_nobufs); | |
555 | _leave(" = -ENOBUFS"); | |
556 | return -ENOBUFS; | |
557 | } | |
558 | EXPORT_SYMBOL(__fscache_read_or_alloc_pages); | |
559 | ||
560 | /* | |
561 | * allocate a block in the cache on which to store a page | |
562 | * - we return: | |
563 | * -ENOMEM - out of memory, nothing done | |
564 | * -ERESTARTSYS - interrupted | |
565 | * -ENOBUFS - no backing object available in which to cache the block | |
566 | * 0 - block allocated | |
567 | */ | |
568 | int __fscache_alloc_page(struct fscache_cookie *cookie, | |
569 | struct page *page, | |
570 | gfp_t gfp) | |
571 | { | |
572 | struct fscache_retrieval *op; | |
573 | struct fscache_object *object; | |
574 | int ret; | |
575 | ||
576 | _enter("%p,%p,,,", cookie, page); | |
577 | ||
578 | fscache_stat(&fscache_n_allocs); | |
579 | ||
580 | if (hlist_empty(&cookie->backing_objects)) | |
581 | goto nobufs; | |
582 | ||
583 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
584 | ASSERTCMP(page, !=, NULL); | |
585 | ||
586 | if (fscache_wait_for_deferred_lookup(cookie) < 0) | |
587 | return -ERESTARTSYS; | |
588 | ||
589 | op = fscache_alloc_retrieval(page->mapping, NULL, NULL); | |
590 | if (!op) | |
591 | return -ENOMEM; | |
440f0aff | 592 | fscache_set_op_name(&op->op, "RetrAL1"); |
b5108822 DH |
593 | |
594 | spin_lock(&cookie->lock); | |
595 | ||
596 | if (hlist_empty(&cookie->backing_objects)) | |
597 | goto nobufs_unlock; | |
598 | object = hlist_entry(cookie->backing_objects.first, | |
599 | struct fscache_object, cookie_link); | |
600 | ||
601 | if (fscache_submit_op(object, &op->op) < 0) | |
602 | goto nobufs_unlock; | |
603 | spin_unlock(&cookie->lock); | |
604 | ||
605 | fscache_stat(&fscache_n_alloc_ops); | |
606 | ||
60d543ca DH |
607 | ret = fscache_wait_for_retrieval_activation( |
608 | object, op, | |
609 | __fscache_stat(&fscache_n_alloc_op_waits), | |
610 | __fscache_stat(&fscache_n_allocs_object_dead)); | |
611 | if (ret < 0) | |
612 | goto error; | |
b5108822 DH |
613 | |
614 | /* ask the cache to honour the operation */ | |
52bd75fd | 615 | fscache_stat(&fscache_n_cop_allocate_page); |
b5108822 | 616 | ret = object->cache->ops->allocate_page(op, page, gfp); |
52bd75fd | 617 | fscache_stat_d(&fscache_n_cop_allocate_page); |
b5108822 | 618 | |
5753c441 DH |
619 | error: |
620 | if (ret == -ERESTARTSYS) | |
621 | fscache_stat(&fscache_n_allocs_intr); | |
622 | else if (ret < 0) | |
b5108822 DH |
623 | fscache_stat(&fscache_n_allocs_nobufs); |
624 | else | |
625 | fscache_stat(&fscache_n_allocs_ok); | |
626 | ||
627 | fscache_put_retrieval(op); | |
628 | _leave(" = %d", ret); | |
629 | return ret; | |
630 | ||
631 | nobufs_unlock: | |
632 | spin_unlock(&cookie->lock); | |
633 | kfree(op); | |
634 | nobufs: | |
635 | fscache_stat(&fscache_n_allocs_nobufs); | |
636 | _leave(" = -ENOBUFS"); | |
637 | return -ENOBUFS; | |
638 | } | |
639 | EXPORT_SYMBOL(__fscache_alloc_page); | |
640 | ||
641 | /* | |
642 | * release a write op reference | |
643 | */ | |
644 | static void fscache_release_write_op(struct fscache_operation *_op) | |
645 | { | |
646 | _enter("{OP%x}", _op->debug_id); | |
647 | } | |
648 | ||
649 | /* | |
650 | * perform the background storage of a page into the cache | |
651 | */ | |
652 | static void fscache_write_op(struct fscache_operation *_op) | |
653 | { | |
654 | struct fscache_storage *op = | |
655 | container_of(_op, struct fscache_storage, op); | |
656 | struct fscache_object *object = op->op.object; | |
1bccf513 | 657 | struct fscache_cookie *cookie; |
b5108822 DH |
658 | struct page *page; |
659 | unsigned n; | |
660 | void *results[1]; | |
661 | int ret; | |
662 | ||
663 | _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage)); | |
664 | ||
440f0aff DH |
665 | fscache_set_op_state(&op->op, "GetPage"); |
666 | ||
b5108822 | 667 | spin_lock(&object->lock); |
1bccf513 | 668 | cookie = object->cookie; |
b5108822 | 669 | |
1bccf513 | 670 | if (!fscache_object_is_active(object) || !cookie) { |
b5108822 | 671 | spin_unlock(&object->lock); |
b5108822 DH |
672 | _leave(""); |
673 | return; | |
674 | } | |
675 | ||
1bccf513 DH |
676 | spin_lock(&cookie->stores_lock); |
677 | ||
b5108822 DH |
678 | fscache_stat(&fscache_n_store_calls); |
679 | ||
680 | /* find a page to store */ | |
681 | page = NULL; | |
682 | n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1, | |
683 | FSCACHE_COOKIE_PENDING_TAG); | |
684 | if (n != 1) | |
685 | goto superseded; | |
686 | page = results[0]; | |
687 | _debug("gang %d [%lx]", n, page->index); | |
1bccf513 DH |
688 | if (page->index > op->store_limit) { |
689 | fscache_stat(&fscache_n_store_pages_over_limit); | |
b5108822 | 690 | goto superseded; |
1bccf513 | 691 | } |
b5108822 | 692 | |
08a66859 DC |
693 | radix_tree_tag_set(&cookie->stores, page->index, |
694 | FSCACHE_COOKIE_STORING_TAG); | |
695 | radix_tree_tag_clear(&cookie->stores, page->index, | |
696 | FSCACHE_COOKIE_PENDING_TAG); | |
b5108822 | 697 | |
1bccf513 | 698 | spin_unlock(&cookie->stores_lock); |
b5108822 | 699 | spin_unlock(&object->lock); |
b5108822 | 700 | |
08a66859 DC |
701 | fscache_set_op_state(&op->op, "Store"); |
702 | fscache_stat(&fscache_n_store_pages); | |
703 | fscache_stat(&fscache_n_cop_write_page); | |
704 | ret = object->cache->ops->write_page(op, page); | |
705 | fscache_stat_d(&fscache_n_cop_write_page); | |
706 | fscache_set_op_state(&op->op, "EndWrite"); | |
707 | fscache_end_page_write(object, page); | |
708 | if (ret < 0) { | |
709 | fscache_set_op_state(&op->op, "Abort"); | |
710 | fscache_abort_object(object); | |
711 | } else { | |
712 | fscache_enqueue_operation(&op->op); | |
b5108822 DH |
713 | } |
714 | ||
715 | _leave(""); | |
716 | return; | |
717 | ||
718 | superseded: | |
719 | /* this writer is going away and there aren't any more things to | |
720 | * write */ | |
721 | _debug("cease"); | |
1bccf513 | 722 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
723 | clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags); |
724 | spin_unlock(&object->lock); | |
b5108822 DH |
725 | _leave(""); |
726 | } | |
727 | ||
728 | /* | |
729 | * request a page be stored in the cache | |
730 | * - returns: | |
731 | * -ENOMEM - out of memory, nothing done | |
732 | * -ENOBUFS - no backing object available in which to cache the page | |
733 | * 0 - dispatched a write - it'll call end_io_func() when finished | |
734 | * | |
735 | * if the cookie still has a backing object at this point, that object can be | |
736 | * in one of a few states with respect to storage processing: | |
737 | * | |
738 | * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is | |
739 | * set) | |
740 | * | |
741 | * (a) no writes yet (set FSCACHE_COOKIE_PENDING_FILL and queue deferred | |
742 | * fill op) | |
743 | * | |
744 | * (b) writes deferred till post-creation (mark page for writing and | |
745 | * return immediately) | |
746 | * | |
747 | * (2) negative lookup, object created, initial fill being made from netfs | |
748 | * (FSCACHE_COOKIE_INITIAL_FILL is set) | |
749 | * | |
750 | * (a) fill point not yet reached this page (mark page for writing and | |
751 | * return) | |
752 | * | |
753 | * (b) fill point passed this page (queue op to store this page) | |
754 | * | |
755 | * (3) object extant (queue op to store this page) | |
756 | * | |
757 | * any other state is invalid | |
758 | */ | |
759 | int __fscache_write_page(struct fscache_cookie *cookie, | |
760 | struct page *page, | |
761 | gfp_t gfp) | |
762 | { | |
763 | struct fscache_storage *op; | |
764 | struct fscache_object *object; | |
765 | int ret; | |
766 | ||
767 | _enter("%p,%x,", cookie, (u32) page->flags); | |
768 | ||
769 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
770 | ASSERT(PageFsCache(page)); | |
771 | ||
772 | fscache_stat(&fscache_n_stores); | |
773 | ||
774 | op = kzalloc(sizeof(*op), GFP_NOIO); | |
775 | if (!op) | |
776 | goto nomem; | |
777 | ||
8af7c124 TH |
778 | fscache_operation_init(&op->op, fscache_write_op, |
779 | fscache_release_write_op); | |
780 | op->op.flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_WAITING); | |
440f0aff | 781 | fscache_set_op_name(&op->op, "Write1"); |
b5108822 DH |
782 | |
783 | ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM); | |
784 | if (ret < 0) | |
785 | goto nomem_free; | |
786 | ||
787 | ret = -ENOBUFS; | |
788 | spin_lock(&cookie->lock); | |
789 | ||
790 | if (hlist_empty(&cookie->backing_objects)) | |
791 | goto nobufs; | |
792 | object = hlist_entry(cookie->backing_objects.first, | |
793 | struct fscache_object, cookie_link); | |
794 | if (test_bit(FSCACHE_IOERROR, &object->cache->flags)) | |
795 | goto nobufs; | |
796 | ||
797 | /* add the page to the pending-storage radix tree on the backing | |
798 | * object */ | |
799 | spin_lock(&object->lock); | |
1bccf513 | 800 | spin_lock(&cookie->stores_lock); |
b5108822 DH |
801 | |
802 | _debug("store limit %llx", (unsigned long long) object->store_limit); | |
803 | ||
804 | ret = radix_tree_insert(&cookie->stores, page->index, page); | |
805 | if (ret < 0) { | |
806 | if (ret == -EEXIST) | |
807 | goto already_queued; | |
808 | _debug("insert failed %d", ret); | |
809 | goto nobufs_unlock_obj; | |
810 | } | |
811 | ||
812 | radix_tree_tag_set(&cookie->stores, page->index, | |
813 | FSCACHE_COOKIE_PENDING_TAG); | |
814 | page_cache_get(page); | |
815 | ||
816 | /* we only want one writer at a time, but we do need to queue new | |
817 | * writers after exclusive ops */ | |
818 | if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags)) | |
819 | goto already_pending; | |
820 | ||
1bccf513 | 821 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
822 | spin_unlock(&object->lock); |
823 | ||
824 | op->op.debug_id = atomic_inc_return(&fscache_op_debug_id); | |
825 | op->store_limit = object->store_limit; | |
826 | ||
827 | if (fscache_submit_op(object, &op->op) < 0) | |
828 | goto submit_failed; | |
829 | ||
830 | spin_unlock(&cookie->lock); | |
831 | radix_tree_preload_end(); | |
832 | fscache_stat(&fscache_n_store_ops); | |
833 | fscache_stat(&fscache_n_stores_ok); | |
834 | ||
8af7c124 | 835 | /* the work queue now carries its own ref on the object */ |
b5108822 DH |
836 | fscache_put_operation(&op->op); |
837 | _leave(" = 0"); | |
838 | return 0; | |
839 | ||
840 | already_queued: | |
841 | fscache_stat(&fscache_n_stores_again); | |
842 | already_pending: | |
1bccf513 | 843 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
844 | spin_unlock(&object->lock); |
845 | spin_unlock(&cookie->lock); | |
846 | radix_tree_preload_end(); | |
847 | kfree(op); | |
848 | fscache_stat(&fscache_n_stores_ok); | |
849 | _leave(" = 0"); | |
850 | return 0; | |
851 | ||
852 | submit_failed: | |
1bccf513 | 853 | spin_lock(&cookie->stores_lock); |
b5108822 | 854 | radix_tree_delete(&cookie->stores, page->index); |
1bccf513 | 855 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
856 | page_cache_release(page); |
857 | ret = -ENOBUFS; | |
858 | goto nobufs; | |
859 | ||
860 | nobufs_unlock_obj: | |
1147d0f9 | 861 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
862 | spin_unlock(&object->lock); |
863 | nobufs: | |
864 | spin_unlock(&cookie->lock); | |
865 | radix_tree_preload_end(); | |
866 | kfree(op); | |
867 | fscache_stat(&fscache_n_stores_nobufs); | |
868 | _leave(" = -ENOBUFS"); | |
869 | return -ENOBUFS; | |
870 | ||
871 | nomem_free: | |
872 | kfree(op); | |
873 | nomem: | |
874 | fscache_stat(&fscache_n_stores_oom); | |
875 | _leave(" = -ENOMEM"); | |
876 | return -ENOMEM; | |
877 | } | |
878 | EXPORT_SYMBOL(__fscache_write_page); | |
879 | ||
880 | /* | |
881 | * remove a page from the cache | |
882 | */ | |
883 | void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page) | |
884 | { | |
885 | struct fscache_object *object; | |
886 | ||
887 | _enter(",%p", page); | |
888 | ||
889 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
890 | ASSERTCMP(page, !=, NULL); | |
891 | ||
892 | fscache_stat(&fscache_n_uncaches); | |
893 | ||
894 | /* cache withdrawal may beat us to it */ | |
895 | if (!PageFsCache(page)) | |
896 | goto done; | |
897 | ||
898 | /* get the object */ | |
899 | spin_lock(&cookie->lock); | |
900 | ||
901 | if (hlist_empty(&cookie->backing_objects)) { | |
902 | ClearPageFsCache(page); | |
903 | goto done_unlock; | |
904 | } | |
905 | ||
906 | object = hlist_entry(cookie->backing_objects.first, | |
907 | struct fscache_object, cookie_link); | |
908 | ||
909 | /* there might now be stuff on disk we could read */ | |
910 | clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); | |
911 | ||
912 | /* only invoke the cache backend if we managed to mark the page | |
913 | * uncached here; this deals with synchronisation vs withdrawal */ | |
914 | if (TestClearPageFsCache(page) && | |
915 | object->cache->ops->uncache_page) { | |
916 | /* the cache backend releases the cookie lock */ | |
52bd75fd | 917 | fscache_stat(&fscache_n_cop_uncache_page); |
b5108822 | 918 | object->cache->ops->uncache_page(object, page); |
52bd75fd | 919 | fscache_stat_d(&fscache_n_cop_uncache_page); |
b5108822 DH |
920 | goto done; |
921 | } | |
922 | ||
923 | done_unlock: | |
924 | spin_unlock(&cookie->lock); | |
925 | done: | |
926 | _leave(""); | |
927 | } | |
928 | EXPORT_SYMBOL(__fscache_uncache_page); | |
929 | ||
930 | /** | |
931 | * fscache_mark_pages_cached - Mark pages as being cached | |
932 | * @op: The retrieval op pages are being marked for | |
933 | * @pagevec: The pages to be marked | |
934 | * | |
935 | * Mark a bunch of netfs pages as being cached. After this is called, | |
936 | * the netfs must call fscache_uncache_page() to remove the mark. | |
937 | */ | |
938 | void fscache_mark_pages_cached(struct fscache_retrieval *op, | |
939 | struct pagevec *pagevec) | |
940 | { | |
941 | struct fscache_cookie *cookie = op->op.object->cookie; | |
942 | unsigned long loop; | |
943 | ||
944 | #ifdef CONFIG_FSCACHE_STATS | |
945 | atomic_add(pagevec->nr, &fscache_n_marks); | |
946 | #endif | |
947 | ||
948 | for (loop = 0; loop < pagevec->nr; loop++) { | |
949 | struct page *page = pagevec->pages[loop]; | |
950 | ||
951 | _debug("- mark %p{%lx}", page, page->index); | |
952 | if (TestSetPageFsCache(page)) { | |
953 | static bool once_only; | |
954 | if (!once_only) { | |
955 | once_only = true; | |
956 | printk(KERN_WARNING "FS-Cache:" | |
957 | " Cookie type %s marked page %lx" | |
958 | " multiple times\n", | |
959 | cookie->def->name, page->index); | |
960 | } | |
961 | } | |
962 | } | |
963 | ||
964 | if (cookie->def->mark_pages_cached) | |
965 | cookie->def->mark_pages_cached(cookie->netfs_data, | |
966 | op->mapping, pagevec); | |
967 | pagevec_reinit(pagevec); | |
968 | } | |
969 | EXPORT_SYMBOL(fscache_mark_pages_cached); |