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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> | |
17 | #include "internal.h" | |
18 | ||
19 | /* | |
20 | * check to see if a page is being written to the cache | |
21 | */ | |
22 | bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page) | |
23 | { | |
24 | void *val; | |
25 | ||
26 | rcu_read_lock(); | |
27 | val = radix_tree_lookup(&cookie->stores, page->index); | |
28 | rcu_read_unlock(); | |
29 | ||
30 | return val != NULL; | |
31 | } | |
32 | EXPORT_SYMBOL(__fscache_check_page_write); | |
33 | ||
34 | /* | |
35 | * wait for a page to finish being written to the cache | |
36 | */ | |
37 | void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page) | |
38 | { | |
39 | wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0); | |
40 | ||
41 | wait_event(*wq, !__fscache_check_page_write(cookie, page)); | |
42 | } | |
43 | EXPORT_SYMBOL(__fscache_wait_on_page_write); | |
44 | ||
45 | /* | |
46 | * note that a page has finished being written to the cache | |
47 | */ | |
1bccf513 DH |
48 | static void fscache_end_page_write(struct fscache_object *object, |
49 | struct page *page) | |
b5108822 | 50 | { |
1bccf513 DH |
51 | struct fscache_cookie *cookie; |
52 | struct page *xpage = NULL; | |
b5108822 | 53 | |
1bccf513 DH |
54 | spin_lock(&object->lock); |
55 | cookie = object->cookie; | |
56 | if (cookie) { | |
57 | /* delete the page from the tree if it is now no longer | |
58 | * pending */ | |
59 | spin_lock(&cookie->stores_lock); | |
60 | fscache_stat(&fscache_n_store_radix_deletes); | |
61 | xpage = radix_tree_delete(&cookie->stores, page->index); | |
62 | spin_unlock(&cookie->stores_lock); | |
63 | wake_up_bit(&cookie->flags, 0); | |
64 | } | |
65 | spin_unlock(&object->lock); | |
66 | if (xpage) | |
67 | page_cache_release(xpage); | |
b5108822 DH |
68 | } |
69 | ||
70 | /* | |
71 | * actually apply the changed attributes to a cache object | |
72 | */ | |
73 | static void fscache_attr_changed_op(struct fscache_operation *op) | |
74 | { | |
75 | struct fscache_object *object = op->object; | |
440f0aff | 76 | int ret; |
b5108822 DH |
77 | |
78 | _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id); | |
79 | ||
80 | fscache_stat(&fscache_n_attr_changed_calls); | |
81 | ||
440f0aff DH |
82 | if (fscache_object_is_active(object)) { |
83 | fscache_set_op_state(op, "CallFS"); | |
52bd75fd | 84 | fscache_stat(&fscache_n_cop_attr_changed); |
440f0aff | 85 | ret = object->cache->ops->attr_changed(object); |
52bd75fd | 86 | fscache_stat_d(&fscache_n_cop_attr_changed); |
440f0aff DH |
87 | fscache_set_op_state(op, "Done"); |
88 | if (ret < 0) | |
89 | fscache_abort_object(object); | |
90 | } | |
b5108822 DH |
91 | |
92 | _leave(""); | |
93 | } | |
94 | ||
95 | /* | |
96 | * notification that the attributes on an object have changed | |
97 | */ | |
98 | int __fscache_attr_changed(struct fscache_cookie *cookie) | |
99 | { | |
100 | struct fscache_operation *op; | |
101 | struct fscache_object *object; | |
102 | ||
103 | _enter("%p", cookie); | |
104 | ||
105 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
106 | ||
107 | fscache_stat(&fscache_n_attr_changed); | |
108 | ||
109 | op = kzalloc(sizeof(*op), GFP_KERNEL); | |
110 | if (!op) { | |
111 | fscache_stat(&fscache_n_attr_changed_nomem); | |
112 | _leave(" = -ENOMEM"); | |
113 | return -ENOMEM; | |
114 | } | |
115 | ||
116 | fscache_operation_init(op, NULL); | |
117 | fscache_operation_init_slow(op, fscache_attr_changed_op); | |
118 | op->flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_EXCLUSIVE); | |
440f0aff | 119 | fscache_set_op_name(op, "Attr"); |
b5108822 DH |
120 | |
121 | spin_lock(&cookie->lock); | |
122 | ||
123 | if (hlist_empty(&cookie->backing_objects)) | |
124 | goto nobufs; | |
125 | object = hlist_entry(cookie->backing_objects.first, | |
126 | struct fscache_object, cookie_link); | |
127 | ||
128 | if (fscache_submit_exclusive_op(object, op) < 0) | |
129 | goto nobufs; | |
130 | spin_unlock(&cookie->lock); | |
131 | fscache_stat(&fscache_n_attr_changed_ok); | |
132 | fscache_put_operation(op); | |
133 | _leave(" = 0"); | |
134 | return 0; | |
135 | ||
136 | nobufs: | |
137 | spin_unlock(&cookie->lock); | |
138 | kfree(op); | |
139 | fscache_stat(&fscache_n_attr_changed_nobufs); | |
140 | _leave(" = %d", -ENOBUFS); | |
141 | return -ENOBUFS; | |
142 | } | |
143 | EXPORT_SYMBOL(__fscache_attr_changed); | |
144 | ||
145 | /* | |
146 | * handle secondary execution given to a retrieval op on behalf of the | |
147 | * cache | |
148 | */ | |
149 | static void fscache_retrieval_work(struct work_struct *work) | |
150 | { | |
151 | struct fscache_retrieval *op = | |
152 | container_of(work, struct fscache_retrieval, op.fast_work); | |
153 | unsigned long start; | |
154 | ||
155 | _enter("{OP%x}", op->op.debug_id); | |
156 | ||
157 | start = jiffies; | |
158 | op->op.processor(&op->op); | |
159 | fscache_hist(fscache_ops_histogram, start); | |
160 | fscache_put_operation(&op->op); | |
161 | } | |
162 | ||
163 | /* | |
164 | * release a retrieval op reference | |
165 | */ | |
166 | static void fscache_release_retrieval_op(struct fscache_operation *_op) | |
167 | { | |
168 | struct fscache_retrieval *op = | |
169 | container_of(_op, struct fscache_retrieval, op); | |
170 | ||
171 | _enter("{OP%x}", op->op.debug_id); | |
172 | ||
173 | fscache_hist(fscache_retrieval_histogram, op->start_time); | |
174 | if (op->context) | |
175 | fscache_put_context(op->op.object->cookie, op->context); | |
176 | ||
177 | _leave(""); | |
178 | } | |
179 | ||
180 | /* | |
181 | * allocate a retrieval op | |
182 | */ | |
183 | static struct fscache_retrieval *fscache_alloc_retrieval( | |
184 | struct address_space *mapping, | |
185 | fscache_rw_complete_t end_io_func, | |
186 | void *context) | |
187 | { | |
188 | struct fscache_retrieval *op; | |
189 | ||
190 | /* allocate a retrieval operation and attempt to submit it */ | |
191 | op = kzalloc(sizeof(*op), GFP_NOIO); | |
192 | if (!op) { | |
193 | fscache_stat(&fscache_n_retrievals_nomem); | |
194 | return NULL; | |
195 | } | |
196 | ||
197 | fscache_operation_init(&op->op, fscache_release_retrieval_op); | |
198 | op->op.flags = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING); | |
199 | op->mapping = mapping; | |
200 | op->end_io_func = end_io_func; | |
201 | op->context = context; | |
202 | op->start_time = jiffies; | |
203 | INIT_WORK(&op->op.fast_work, fscache_retrieval_work); | |
204 | INIT_LIST_HEAD(&op->to_do); | |
440f0aff | 205 | fscache_set_op_name(&op->op, "Retr"); |
b5108822 DH |
206 | return op; |
207 | } | |
208 | ||
209 | /* | |
210 | * wait for a deferred lookup to complete | |
211 | */ | |
212 | static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie) | |
213 | { | |
214 | unsigned long jif; | |
215 | ||
216 | _enter(""); | |
217 | ||
218 | if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) { | |
219 | _leave(" = 0 [imm]"); | |
220 | return 0; | |
221 | } | |
222 | ||
223 | fscache_stat(&fscache_n_retrievals_wait); | |
224 | ||
225 | jif = jiffies; | |
226 | if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP, | |
227 | fscache_wait_bit_interruptible, | |
228 | TASK_INTERRUPTIBLE) != 0) { | |
229 | fscache_stat(&fscache_n_retrievals_intr); | |
230 | _leave(" = -ERESTARTSYS"); | |
231 | return -ERESTARTSYS; | |
232 | } | |
233 | ||
234 | ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)); | |
235 | ||
236 | smp_rmb(); | |
237 | fscache_hist(fscache_retrieval_delay_histogram, jif); | |
238 | _leave(" = 0 [dly]"); | |
239 | return 0; | |
240 | } | |
241 | ||
242 | /* | |
243 | * read a page from the cache or allocate a block in which to store it | |
244 | * - we return: | |
245 | * -ENOMEM - out of memory, nothing done | |
246 | * -ERESTARTSYS - interrupted | |
247 | * -ENOBUFS - no backing object available in which to cache the block | |
248 | * -ENODATA - no data available in the backing object for this block | |
249 | * 0 - dispatched a read - it'll call end_io_func() when finished | |
250 | */ | |
251 | int __fscache_read_or_alloc_page(struct fscache_cookie *cookie, | |
252 | struct page *page, | |
253 | fscache_rw_complete_t end_io_func, | |
254 | void *context, | |
255 | gfp_t gfp) | |
256 | { | |
257 | struct fscache_retrieval *op; | |
258 | struct fscache_object *object; | |
259 | int ret; | |
260 | ||
261 | _enter("%p,%p,,,", cookie, page); | |
262 | ||
263 | fscache_stat(&fscache_n_retrievals); | |
264 | ||
265 | if (hlist_empty(&cookie->backing_objects)) | |
266 | goto nobufs; | |
267 | ||
268 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
269 | ASSERTCMP(page, !=, NULL); | |
270 | ||
271 | if (fscache_wait_for_deferred_lookup(cookie) < 0) | |
272 | return -ERESTARTSYS; | |
273 | ||
274 | op = fscache_alloc_retrieval(page->mapping, end_io_func, context); | |
275 | if (!op) { | |
276 | _leave(" = -ENOMEM"); | |
277 | return -ENOMEM; | |
278 | } | |
440f0aff | 279 | fscache_set_op_name(&op->op, "RetrRA1"); |
b5108822 DH |
280 | |
281 | spin_lock(&cookie->lock); | |
282 | ||
283 | if (hlist_empty(&cookie->backing_objects)) | |
284 | goto nobufs_unlock; | |
285 | object = hlist_entry(cookie->backing_objects.first, | |
286 | struct fscache_object, cookie_link); | |
287 | ||
288 | ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP); | |
289 | ||
4fbf4291 DH |
290 | atomic_inc(&object->n_reads); |
291 | set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags); | |
292 | ||
b5108822 DH |
293 | if (fscache_submit_op(object, &op->op) < 0) |
294 | goto nobufs_unlock; | |
295 | spin_unlock(&cookie->lock); | |
296 | ||
297 | fscache_stat(&fscache_n_retrieval_ops); | |
298 | ||
299 | /* pin the netfs read context in case we need to do the actual netfs | |
300 | * read because we've encountered a cache read failure */ | |
301 | fscache_get_context(object->cookie, op->context); | |
302 | ||
303 | /* we wait for the operation to become active, and then process it | |
304 | * *here*, in this thread, and not in the thread pool */ | |
305 | if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) { | |
306 | _debug(">>> WT"); | |
307 | fscache_stat(&fscache_n_retrieval_op_waits); | |
5753c441 DH |
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 | ret = -ERESTARTSYS; | |
314 | goto error; | |
315 | } | |
316 | ||
317 | /* it's been removed from the pending queue by another | |
318 | * party, so we should get to run shortly */ | |
319 | wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, | |
320 | fscache_wait_bit, TASK_UNINTERRUPTIBLE); | |
321 | } | |
b5108822 DH |
322 | _debug("<<< GO"); |
323 | } | |
324 | ||
325 | /* ask the cache to honour the operation */ | |
326 | if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { | |
52bd75fd | 327 | fscache_stat(&fscache_n_cop_allocate_page); |
b5108822 | 328 | ret = object->cache->ops->allocate_page(op, page, gfp); |
52bd75fd | 329 | fscache_stat_d(&fscache_n_cop_allocate_page); |
b5108822 DH |
330 | if (ret == 0) |
331 | ret = -ENODATA; | |
332 | } else { | |
52bd75fd | 333 | fscache_stat(&fscache_n_cop_read_or_alloc_page); |
b5108822 | 334 | ret = object->cache->ops->read_or_alloc_page(op, page, gfp); |
52bd75fd | 335 | fscache_stat_d(&fscache_n_cop_read_or_alloc_page); |
b5108822 DH |
336 | } |
337 | ||
5753c441 | 338 | error: |
b5108822 DH |
339 | if (ret == -ENOMEM) |
340 | fscache_stat(&fscache_n_retrievals_nomem); | |
341 | else if (ret == -ERESTARTSYS) | |
342 | fscache_stat(&fscache_n_retrievals_intr); | |
343 | else if (ret == -ENODATA) | |
344 | fscache_stat(&fscache_n_retrievals_nodata); | |
345 | else if (ret < 0) | |
346 | fscache_stat(&fscache_n_retrievals_nobufs); | |
347 | else | |
348 | fscache_stat(&fscache_n_retrievals_ok); | |
349 | ||
350 | fscache_put_retrieval(op); | |
351 | _leave(" = %d", ret); | |
352 | return ret; | |
353 | ||
354 | nobufs_unlock: | |
355 | spin_unlock(&cookie->lock); | |
356 | kfree(op); | |
357 | nobufs: | |
358 | fscache_stat(&fscache_n_retrievals_nobufs); | |
359 | _leave(" = -ENOBUFS"); | |
360 | return -ENOBUFS; | |
361 | } | |
362 | EXPORT_SYMBOL(__fscache_read_or_alloc_page); | |
363 | ||
364 | /* | |
365 | * read a list of page from the cache or allocate a block in which to store | |
366 | * them | |
367 | * - we return: | |
368 | * -ENOMEM - out of memory, some pages may be being read | |
369 | * -ERESTARTSYS - interrupted, some pages may be being read | |
370 | * -ENOBUFS - no backing object or space available in which to cache any | |
371 | * pages not being read | |
372 | * -ENODATA - no data available in the backing object for some or all of | |
373 | * the pages | |
374 | * 0 - dispatched a read on all pages | |
375 | * | |
376 | * end_io_func() will be called for each page read from the cache as it is | |
377 | * finishes being read | |
378 | * | |
379 | * any pages for which a read is dispatched will be removed from pages and | |
380 | * nr_pages | |
381 | */ | |
382 | int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie, | |
383 | struct address_space *mapping, | |
384 | struct list_head *pages, | |
385 | unsigned *nr_pages, | |
386 | fscache_rw_complete_t end_io_func, | |
387 | void *context, | |
388 | gfp_t gfp) | |
389 | { | |
b5108822 DH |
390 | struct fscache_retrieval *op; |
391 | struct fscache_object *object; | |
392 | int ret; | |
393 | ||
394 | _enter("%p,,%d,,,", cookie, *nr_pages); | |
395 | ||
396 | fscache_stat(&fscache_n_retrievals); | |
397 | ||
398 | if (hlist_empty(&cookie->backing_objects)) | |
399 | goto nobufs; | |
400 | ||
401 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
402 | ASSERTCMP(*nr_pages, >, 0); | |
403 | ASSERT(!list_empty(pages)); | |
404 | ||
405 | if (fscache_wait_for_deferred_lookup(cookie) < 0) | |
406 | return -ERESTARTSYS; | |
407 | ||
408 | op = fscache_alloc_retrieval(mapping, end_io_func, context); | |
409 | if (!op) | |
410 | return -ENOMEM; | |
440f0aff | 411 | fscache_set_op_name(&op->op, "RetrRAN"); |
b5108822 DH |
412 | |
413 | spin_lock(&cookie->lock); | |
414 | ||
415 | if (hlist_empty(&cookie->backing_objects)) | |
416 | goto nobufs_unlock; | |
417 | object = hlist_entry(cookie->backing_objects.first, | |
418 | struct fscache_object, cookie_link); | |
419 | ||
4fbf4291 DH |
420 | atomic_inc(&object->n_reads); |
421 | set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags); | |
422 | ||
b5108822 DH |
423 | if (fscache_submit_op(object, &op->op) < 0) |
424 | goto nobufs_unlock; | |
425 | spin_unlock(&cookie->lock); | |
426 | ||
427 | fscache_stat(&fscache_n_retrieval_ops); | |
428 | ||
429 | /* pin the netfs read context in case we need to do the actual netfs | |
430 | * read because we've encountered a cache read failure */ | |
431 | fscache_get_context(object->cookie, op->context); | |
432 | ||
433 | /* we wait for the operation to become active, and then process it | |
434 | * *here*, in this thread, and not in the thread pool */ | |
435 | if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) { | |
436 | _debug(">>> WT"); | |
437 | fscache_stat(&fscache_n_retrieval_op_waits); | |
5753c441 DH |
438 | if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, |
439 | fscache_wait_bit_interruptible, | |
440 | TASK_INTERRUPTIBLE) < 0) { | |
441 | ret = fscache_cancel_op(&op->op); | |
442 | if (ret == 0) { | |
443 | ret = -ERESTARTSYS; | |
444 | goto error; | |
445 | } | |
446 | ||
447 | /* it's been removed from the pending queue by another | |
448 | * party, so we should get to run shortly */ | |
449 | wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, | |
450 | fscache_wait_bit, TASK_UNINTERRUPTIBLE); | |
451 | } | |
b5108822 DH |
452 | _debug("<<< GO"); |
453 | } | |
454 | ||
455 | /* ask the cache to honour the operation */ | |
52bd75fd DH |
456 | if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { |
457 | fscache_stat(&fscache_n_cop_allocate_pages); | |
458 | ret = object->cache->ops->allocate_pages( | |
459 | op, pages, nr_pages, gfp); | |
460 | fscache_stat_d(&fscache_n_cop_allocate_pages); | |
461 | } else { | |
462 | fscache_stat(&fscache_n_cop_read_or_alloc_pages); | |
463 | ret = object->cache->ops->read_or_alloc_pages( | |
464 | op, pages, nr_pages, gfp); | |
465 | fscache_stat_d(&fscache_n_cop_read_or_alloc_pages); | |
466 | } | |
b5108822 | 467 | |
5753c441 | 468 | error: |
b5108822 DH |
469 | if (ret == -ENOMEM) |
470 | fscache_stat(&fscache_n_retrievals_nomem); | |
471 | else if (ret == -ERESTARTSYS) | |
472 | fscache_stat(&fscache_n_retrievals_intr); | |
473 | else if (ret == -ENODATA) | |
474 | fscache_stat(&fscache_n_retrievals_nodata); | |
475 | else if (ret < 0) | |
476 | fscache_stat(&fscache_n_retrievals_nobufs); | |
477 | else | |
478 | fscache_stat(&fscache_n_retrievals_ok); | |
479 | ||
480 | fscache_put_retrieval(op); | |
481 | _leave(" = %d", ret); | |
482 | return ret; | |
483 | ||
484 | nobufs_unlock: | |
485 | spin_unlock(&cookie->lock); | |
486 | kfree(op); | |
487 | nobufs: | |
488 | fscache_stat(&fscache_n_retrievals_nobufs); | |
489 | _leave(" = -ENOBUFS"); | |
490 | return -ENOBUFS; | |
491 | } | |
492 | EXPORT_SYMBOL(__fscache_read_or_alloc_pages); | |
493 | ||
494 | /* | |
495 | * allocate a block in the cache on which to store a page | |
496 | * - we return: | |
497 | * -ENOMEM - out of memory, nothing done | |
498 | * -ERESTARTSYS - interrupted | |
499 | * -ENOBUFS - no backing object available in which to cache the block | |
500 | * 0 - block allocated | |
501 | */ | |
502 | int __fscache_alloc_page(struct fscache_cookie *cookie, | |
503 | struct page *page, | |
504 | gfp_t gfp) | |
505 | { | |
506 | struct fscache_retrieval *op; | |
507 | struct fscache_object *object; | |
508 | int ret; | |
509 | ||
510 | _enter("%p,%p,,,", cookie, page); | |
511 | ||
512 | fscache_stat(&fscache_n_allocs); | |
513 | ||
514 | if (hlist_empty(&cookie->backing_objects)) | |
515 | goto nobufs; | |
516 | ||
517 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
518 | ASSERTCMP(page, !=, NULL); | |
519 | ||
520 | if (fscache_wait_for_deferred_lookup(cookie) < 0) | |
521 | return -ERESTARTSYS; | |
522 | ||
523 | op = fscache_alloc_retrieval(page->mapping, NULL, NULL); | |
524 | if (!op) | |
525 | return -ENOMEM; | |
440f0aff | 526 | fscache_set_op_name(&op->op, "RetrAL1"); |
b5108822 DH |
527 | |
528 | spin_lock(&cookie->lock); | |
529 | ||
530 | if (hlist_empty(&cookie->backing_objects)) | |
531 | goto nobufs_unlock; | |
532 | object = hlist_entry(cookie->backing_objects.first, | |
533 | struct fscache_object, cookie_link); | |
534 | ||
535 | if (fscache_submit_op(object, &op->op) < 0) | |
536 | goto nobufs_unlock; | |
537 | spin_unlock(&cookie->lock); | |
538 | ||
539 | fscache_stat(&fscache_n_alloc_ops); | |
540 | ||
541 | if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) { | |
542 | _debug(">>> WT"); | |
543 | fscache_stat(&fscache_n_alloc_op_waits); | |
5753c441 DH |
544 | if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, |
545 | fscache_wait_bit_interruptible, | |
546 | TASK_INTERRUPTIBLE) < 0) { | |
547 | ret = fscache_cancel_op(&op->op); | |
548 | if (ret == 0) { | |
549 | ret = -ERESTARTSYS; | |
550 | goto error; | |
551 | } | |
552 | ||
553 | /* it's been removed from the pending queue by another | |
554 | * party, so we should get to run shortly */ | |
555 | wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, | |
556 | fscache_wait_bit, TASK_UNINTERRUPTIBLE); | |
557 | } | |
b5108822 DH |
558 | _debug("<<< GO"); |
559 | } | |
560 | ||
561 | /* ask the cache to honour the operation */ | |
52bd75fd | 562 | fscache_stat(&fscache_n_cop_allocate_page); |
b5108822 | 563 | ret = object->cache->ops->allocate_page(op, page, gfp); |
52bd75fd | 564 | fscache_stat_d(&fscache_n_cop_allocate_page); |
b5108822 | 565 | |
5753c441 DH |
566 | error: |
567 | if (ret == -ERESTARTSYS) | |
568 | fscache_stat(&fscache_n_allocs_intr); | |
569 | else if (ret < 0) | |
b5108822 DH |
570 | fscache_stat(&fscache_n_allocs_nobufs); |
571 | else | |
572 | fscache_stat(&fscache_n_allocs_ok); | |
573 | ||
574 | fscache_put_retrieval(op); | |
575 | _leave(" = %d", ret); | |
576 | return ret; | |
577 | ||
578 | nobufs_unlock: | |
579 | spin_unlock(&cookie->lock); | |
580 | kfree(op); | |
581 | nobufs: | |
582 | fscache_stat(&fscache_n_allocs_nobufs); | |
583 | _leave(" = -ENOBUFS"); | |
584 | return -ENOBUFS; | |
585 | } | |
586 | EXPORT_SYMBOL(__fscache_alloc_page); | |
587 | ||
588 | /* | |
589 | * release a write op reference | |
590 | */ | |
591 | static void fscache_release_write_op(struct fscache_operation *_op) | |
592 | { | |
593 | _enter("{OP%x}", _op->debug_id); | |
594 | } | |
595 | ||
596 | /* | |
597 | * perform the background storage of a page into the cache | |
598 | */ | |
599 | static void fscache_write_op(struct fscache_operation *_op) | |
600 | { | |
601 | struct fscache_storage *op = | |
602 | container_of(_op, struct fscache_storage, op); | |
603 | struct fscache_object *object = op->op.object; | |
1bccf513 | 604 | struct fscache_cookie *cookie; |
b5108822 DH |
605 | struct page *page; |
606 | unsigned n; | |
607 | void *results[1]; | |
608 | int ret; | |
609 | ||
610 | _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage)); | |
611 | ||
440f0aff DH |
612 | fscache_set_op_state(&op->op, "GetPage"); |
613 | ||
b5108822 | 614 | spin_lock(&object->lock); |
1bccf513 | 615 | cookie = object->cookie; |
b5108822 | 616 | |
1bccf513 | 617 | if (!fscache_object_is_active(object) || !cookie) { |
b5108822 | 618 | spin_unlock(&object->lock); |
b5108822 DH |
619 | _leave(""); |
620 | return; | |
621 | } | |
622 | ||
1bccf513 DH |
623 | spin_lock(&cookie->stores_lock); |
624 | ||
b5108822 DH |
625 | fscache_stat(&fscache_n_store_calls); |
626 | ||
627 | /* find a page to store */ | |
628 | page = NULL; | |
629 | n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1, | |
630 | FSCACHE_COOKIE_PENDING_TAG); | |
631 | if (n != 1) | |
632 | goto superseded; | |
633 | page = results[0]; | |
634 | _debug("gang %d [%lx]", n, page->index); | |
1bccf513 DH |
635 | if (page->index > op->store_limit) { |
636 | fscache_stat(&fscache_n_store_pages_over_limit); | |
b5108822 | 637 | goto superseded; |
1bccf513 | 638 | } |
b5108822 DH |
639 | |
640 | radix_tree_tag_clear(&cookie->stores, page->index, | |
641 | FSCACHE_COOKIE_PENDING_TAG); | |
642 | ||
1bccf513 | 643 | spin_unlock(&cookie->stores_lock); |
b5108822 | 644 | spin_unlock(&object->lock); |
b5108822 DH |
645 | |
646 | if (page) { | |
440f0aff | 647 | fscache_set_op_state(&op->op, "Store"); |
1bccf513 | 648 | fscache_stat(&fscache_n_store_pages); |
52bd75fd | 649 | fscache_stat(&fscache_n_cop_write_page); |
b5108822 | 650 | ret = object->cache->ops->write_page(op, page); |
52bd75fd | 651 | fscache_stat_d(&fscache_n_cop_write_page); |
440f0aff | 652 | fscache_set_op_state(&op->op, "EndWrite"); |
1bccf513 | 653 | fscache_end_page_write(object, page); |
440f0aff DH |
654 | if (ret < 0) { |
655 | fscache_set_op_state(&op->op, "Abort"); | |
b5108822 | 656 | fscache_abort_object(object); |
440f0aff | 657 | } else { |
b5108822 | 658 | fscache_enqueue_operation(&op->op); |
440f0aff | 659 | } |
b5108822 DH |
660 | } |
661 | ||
662 | _leave(""); | |
663 | return; | |
664 | ||
665 | superseded: | |
666 | /* this writer is going away and there aren't any more things to | |
667 | * write */ | |
668 | _debug("cease"); | |
1bccf513 | 669 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
670 | clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags); |
671 | spin_unlock(&object->lock); | |
b5108822 DH |
672 | _leave(""); |
673 | } | |
674 | ||
675 | /* | |
676 | * request a page be stored in the cache | |
677 | * - returns: | |
678 | * -ENOMEM - out of memory, nothing done | |
679 | * -ENOBUFS - no backing object available in which to cache the page | |
680 | * 0 - dispatched a write - it'll call end_io_func() when finished | |
681 | * | |
682 | * if the cookie still has a backing object at this point, that object can be | |
683 | * in one of a few states with respect to storage processing: | |
684 | * | |
685 | * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is | |
686 | * set) | |
687 | * | |
688 | * (a) no writes yet (set FSCACHE_COOKIE_PENDING_FILL and queue deferred | |
689 | * fill op) | |
690 | * | |
691 | * (b) writes deferred till post-creation (mark page for writing and | |
692 | * return immediately) | |
693 | * | |
694 | * (2) negative lookup, object created, initial fill being made from netfs | |
695 | * (FSCACHE_COOKIE_INITIAL_FILL is set) | |
696 | * | |
697 | * (a) fill point not yet reached this page (mark page for writing and | |
698 | * return) | |
699 | * | |
700 | * (b) fill point passed this page (queue op to store this page) | |
701 | * | |
702 | * (3) object extant (queue op to store this page) | |
703 | * | |
704 | * any other state is invalid | |
705 | */ | |
706 | int __fscache_write_page(struct fscache_cookie *cookie, | |
707 | struct page *page, | |
708 | gfp_t gfp) | |
709 | { | |
710 | struct fscache_storage *op; | |
711 | struct fscache_object *object; | |
712 | int ret; | |
713 | ||
714 | _enter("%p,%x,", cookie, (u32) page->flags); | |
715 | ||
716 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
717 | ASSERT(PageFsCache(page)); | |
718 | ||
719 | fscache_stat(&fscache_n_stores); | |
720 | ||
721 | op = kzalloc(sizeof(*op), GFP_NOIO); | |
722 | if (!op) | |
723 | goto nomem; | |
724 | ||
725 | fscache_operation_init(&op->op, fscache_release_write_op); | |
726 | fscache_operation_init_slow(&op->op, fscache_write_op); | |
727 | op->op.flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_WAITING); | |
440f0aff | 728 | fscache_set_op_name(&op->op, "Write1"); |
b5108822 DH |
729 | |
730 | ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM); | |
731 | if (ret < 0) | |
732 | goto nomem_free; | |
733 | ||
734 | ret = -ENOBUFS; | |
735 | spin_lock(&cookie->lock); | |
736 | ||
737 | if (hlist_empty(&cookie->backing_objects)) | |
738 | goto nobufs; | |
739 | object = hlist_entry(cookie->backing_objects.first, | |
740 | struct fscache_object, cookie_link); | |
741 | if (test_bit(FSCACHE_IOERROR, &object->cache->flags)) | |
742 | goto nobufs; | |
743 | ||
744 | /* add the page to the pending-storage radix tree on the backing | |
745 | * object */ | |
746 | spin_lock(&object->lock); | |
1bccf513 | 747 | spin_lock(&cookie->stores_lock); |
b5108822 DH |
748 | |
749 | _debug("store limit %llx", (unsigned long long) object->store_limit); | |
750 | ||
751 | ret = radix_tree_insert(&cookie->stores, page->index, page); | |
752 | if (ret < 0) { | |
753 | if (ret == -EEXIST) | |
754 | goto already_queued; | |
755 | _debug("insert failed %d", ret); | |
756 | goto nobufs_unlock_obj; | |
757 | } | |
758 | ||
759 | radix_tree_tag_set(&cookie->stores, page->index, | |
760 | FSCACHE_COOKIE_PENDING_TAG); | |
761 | page_cache_get(page); | |
762 | ||
763 | /* we only want one writer at a time, but we do need to queue new | |
764 | * writers after exclusive ops */ | |
765 | if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags)) | |
766 | goto already_pending; | |
767 | ||
1bccf513 | 768 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
769 | spin_unlock(&object->lock); |
770 | ||
771 | op->op.debug_id = atomic_inc_return(&fscache_op_debug_id); | |
772 | op->store_limit = object->store_limit; | |
773 | ||
774 | if (fscache_submit_op(object, &op->op) < 0) | |
775 | goto submit_failed; | |
776 | ||
777 | spin_unlock(&cookie->lock); | |
778 | radix_tree_preload_end(); | |
779 | fscache_stat(&fscache_n_store_ops); | |
780 | fscache_stat(&fscache_n_stores_ok); | |
781 | ||
782 | /* the slow work queue now carries its own ref on the object */ | |
783 | fscache_put_operation(&op->op); | |
784 | _leave(" = 0"); | |
785 | return 0; | |
786 | ||
787 | already_queued: | |
788 | fscache_stat(&fscache_n_stores_again); | |
789 | already_pending: | |
1bccf513 | 790 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
791 | spin_unlock(&object->lock); |
792 | spin_unlock(&cookie->lock); | |
793 | radix_tree_preload_end(); | |
794 | kfree(op); | |
795 | fscache_stat(&fscache_n_stores_ok); | |
796 | _leave(" = 0"); | |
797 | return 0; | |
798 | ||
799 | submit_failed: | |
1bccf513 | 800 | spin_lock(&cookie->stores_lock); |
b5108822 | 801 | radix_tree_delete(&cookie->stores, page->index); |
1bccf513 | 802 | spin_unlock(&cookie->stores_lock); |
b5108822 DH |
803 | page_cache_release(page); |
804 | ret = -ENOBUFS; | |
805 | goto nobufs; | |
806 | ||
807 | nobufs_unlock_obj: | |
808 | spin_unlock(&object->lock); | |
809 | nobufs: | |
810 | spin_unlock(&cookie->lock); | |
811 | radix_tree_preload_end(); | |
812 | kfree(op); | |
813 | fscache_stat(&fscache_n_stores_nobufs); | |
814 | _leave(" = -ENOBUFS"); | |
815 | return -ENOBUFS; | |
816 | ||
817 | nomem_free: | |
818 | kfree(op); | |
819 | nomem: | |
820 | fscache_stat(&fscache_n_stores_oom); | |
821 | _leave(" = -ENOMEM"); | |
822 | return -ENOMEM; | |
823 | } | |
824 | EXPORT_SYMBOL(__fscache_write_page); | |
825 | ||
826 | /* | |
827 | * remove a page from the cache | |
828 | */ | |
829 | void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page) | |
830 | { | |
831 | struct fscache_object *object; | |
832 | ||
833 | _enter(",%p", page); | |
834 | ||
835 | ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX); | |
836 | ASSERTCMP(page, !=, NULL); | |
837 | ||
838 | fscache_stat(&fscache_n_uncaches); | |
839 | ||
840 | /* cache withdrawal may beat us to it */ | |
841 | if (!PageFsCache(page)) | |
842 | goto done; | |
843 | ||
844 | /* get the object */ | |
845 | spin_lock(&cookie->lock); | |
846 | ||
847 | if (hlist_empty(&cookie->backing_objects)) { | |
848 | ClearPageFsCache(page); | |
849 | goto done_unlock; | |
850 | } | |
851 | ||
852 | object = hlist_entry(cookie->backing_objects.first, | |
853 | struct fscache_object, cookie_link); | |
854 | ||
855 | /* there might now be stuff on disk we could read */ | |
856 | clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); | |
857 | ||
858 | /* only invoke the cache backend if we managed to mark the page | |
859 | * uncached here; this deals with synchronisation vs withdrawal */ | |
860 | if (TestClearPageFsCache(page) && | |
861 | object->cache->ops->uncache_page) { | |
862 | /* the cache backend releases the cookie lock */ | |
52bd75fd | 863 | fscache_stat(&fscache_n_cop_uncache_page); |
b5108822 | 864 | object->cache->ops->uncache_page(object, page); |
52bd75fd | 865 | fscache_stat_d(&fscache_n_cop_uncache_page); |
b5108822 DH |
866 | goto done; |
867 | } | |
868 | ||
869 | done_unlock: | |
870 | spin_unlock(&cookie->lock); | |
871 | done: | |
872 | _leave(""); | |
873 | } | |
874 | EXPORT_SYMBOL(__fscache_uncache_page); | |
875 | ||
876 | /** | |
877 | * fscache_mark_pages_cached - Mark pages as being cached | |
878 | * @op: The retrieval op pages are being marked for | |
879 | * @pagevec: The pages to be marked | |
880 | * | |
881 | * Mark a bunch of netfs pages as being cached. After this is called, | |
882 | * the netfs must call fscache_uncache_page() to remove the mark. | |
883 | */ | |
884 | void fscache_mark_pages_cached(struct fscache_retrieval *op, | |
885 | struct pagevec *pagevec) | |
886 | { | |
887 | struct fscache_cookie *cookie = op->op.object->cookie; | |
888 | unsigned long loop; | |
889 | ||
890 | #ifdef CONFIG_FSCACHE_STATS | |
891 | atomic_add(pagevec->nr, &fscache_n_marks); | |
892 | #endif | |
893 | ||
894 | for (loop = 0; loop < pagevec->nr; loop++) { | |
895 | struct page *page = pagevec->pages[loop]; | |
896 | ||
897 | _debug("- mark %p{%lx}", page, page->index); | |
898 | if (TestSetPageFsCache(page)) { | |
899 | static bool once_only; | |
900 | if (!once_only) { | |
901 | once_only = true; | |
902 | printk(KERN_WARNING "FS-Cache:" | |
903 | " Cookie type %s marked page %lx" | |
904 | " multiple times\n", | |
905 | cookie->def->name, page->index); | |
906 | } | |
907 | } | |
908 | } | |
909 | ||
910 | if (cookie->def->mark_pages_cached) | |
911 | cookie->def->mark_pages_cached(cookie->netfs_data, | |
912 | op->mapping, pagevec); | |
913 | pagevec_reinit(pagevec); | |
914 | } | |
915 | EXPORT_SYMBOL(fscache_mark_pages_cached); |