blob: 483bbc613bf04528cbc66d5d54a5b54b6a8dc85b [file] [log] [blame]
David Howellsb5108822009-04-03 16:42:39 +01001/* Cache page management and data I/O routines
2 *
3 * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define FSCACHE_DEBUG_LEVEL PAGE
13#include <linux/module.h>
14#include <linux/fscache-cache.h>
15#include <linux/buffer_head.h>
16#include <linux/pagevec.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090017#include <linux/slab.h>
David Howellsb5108822009-04-03 16:42:39 +010018#include "internal.h"
19
20/*
21 * check to see if a page is being written to the cache
22 */
23bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page *page)
24{
25 void *val;
26
27 rcu_read_lock();
28 val = radix_tree_lookup(&cookie->stores, page->index);
29 rcu_read_unlock();
30
31 return val != NULL;
32}
33EXPORT_SYMBOL(__fscache_check_page_write);
34
35/*
36 * wait for a page to finish being written to the cache
37 */
38void __fscache_wait_on_page_write(struct fscache_cookie *cookie, struct page *page)
39{
40 wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
41
42 wait_event(*wq, !__fscache_check_page_write(cookie, page));
43}
44EXPORT_SYMBOL(__fscache_wait_on_page_write);
45
46/*
Milosz Tanski9776de92014-08-13 12:58:16 -040047 * wait for a page to finish being written to the cache. Put a timeout here
48 * since we might be called recursively via parent fs.
49 */
50static
51bool release_page_wait_timeout(struct fscache_cookie *cookie, struct page *page)
52{
53 wait_queue_head_t *wq = bit_waitqueue(&cookie->flags, 0);
54
55 return wait_event_timeout(*wq, !__fscache_check_page_write(cookie, page),
56 HZ);
57}
58
59/*
David Howells201a1542009-11-19 18:11:35 +000060 * decide whether a page can be released, possibly by cancelling a store to it
61 * - we're allowed to sleep if __GFP_WAIT is flagged
62 */
63bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
64 struct page *page,
65 gfp_t gfp)
66{
67 struct page *xpage;
68 void *val;
69
70 _enter("%p,%p,%x", cookie, page, gfp);
71
David Howells8c209ce2012-12-05 13:34:49 +000072try_again:
David Howells201a1542009-11-19 18:11:35 +000073 rcu_read_lock();
74 val = radix_tree_lookup(&cookie->stores, page->index);
75 if (!val) {
76 rcu_read_unlock();
77 fscache_stat(&fscache_n_store_vmscan_not_storing);
78 __fscache_uncache_page(cookie, page);
79 return true;
80 }
81
82 /* see if the page is actually undergoing storage - if so we can't get
83 * rid of it till the cache has finished with it */
84 if (radix_tree_tag_get(&cookie->stores, page->index,
85 FSCACHE_COOKIE_STORING_TAG)) {
86 rcu_read_unlock();
87 goto page_busy;
88 }
89
90 /* the page is pending storage, so we attempt to cancel the store and
91 * discard the store request so that the page can be reclaimed */
92 spin_lock(&cookie->stores_lock);
93 rcu_read_unlock();
94
95 if (radix_tree_tag_get(&cookie->stores, page->index,
96 FSCACHE_COOKIE_STORING_TAG)) {
97 /* the page started to undergo storage whilst we were looking,
98 * so now we can only wait or return */
99 spin_unlock(&cookie->stores_lock);
100 goto page_busy;
101 }
102
103 xpage = radix_tree_delete(&cookie->stores, page->index);
104 spin_unlock(&cookie->stores_lock);
105
106 if (xpage) {
107 fscache_stat(&fscache_n_store_vmscan_cancelled);
108 fscache_stat(&fscache_n_store_radix_deletes);
109 ASSERTCMP(xpage, ==, page);
110 } else {
111 fscache_stat(&fscache_n_store_vmscan_gone);
112 }
113
114 wake_up_bit(&cookie->flags, 0);
115 if (xpage)
116 page_cache_release(xpage);
117 __fscache_uncache_page(cookie, page);
118 return true;
119
120page_busy:
David Howells8c209ce2012-12-05 13:34:49 +0000121 /* We will wait here if we're allowed to, but that could deadlock the
122 * allocator as the work threads writing to the cache may all end up
123 * sleeping on memory allocation, so we may need to impose a timeout
124 * too. */
David Howells0c59a952013-05-10 19:50:25 +0100125 if (!(gfp & __GFP_WAIT) || !(gfp & __GFP_FS)) {
David Howells8c209ce2012-12-05 13:34:49 +0000126 fscache_stat(&fscache_n_store_vmscan_busy);
127 return false;
128 }
129
130 fscache_stat(&fscache_n_store_vmscan_wait);
Milosz Tanski9776de92014-08-13 12:58:16 -0400131 if (!release_page_wait_timeout(cookie, page))
132 _debug("fscache writeout timeout page: %p{%lx}",
133 page, page->index);
134
David Howells8c209ce2012-12-05 13:34:49 +0000135 gfp &= ~__GFP_WAIT;
136 goto try_again;
David Howells201a1542009-11-19 18:11:35 +0000137}
138EXPORT_SYMBOL(__fscache_maybe_release_page);
139
140/*
David Howellsb5108822009-04-03 16:42:39 +0100141 * note that a page has finished being written to the cache
142 */
David Howells1bccf512009-11-19 18:11:25 +0000143static void fscache_end_page_write(struct fscache_object *object,
144 struct page *page)
David Howellsb5108822009-04-03 16:42:39 +0100145{
David Howells1bccf512009-11-19 18:11:25 +0000146 struct fscache_cookie *cookie;
147 struct page *xpage = NULL;
David Howellsb5108822009-04-03 16:42:39 +0100148
David Howells1bccf512009-11-19 18:11:25 +0000149 spin_lock(&object->lock);
150 cookie = object->cookie;
151 if (cookie) {
152 /* delete the page from the tree if it is now no longer
153 * pending */
154 spin_lock(&cookie->stores_lock);
David Howells201a1542009-11-19 18:11:35 +0000155 radix_tree_tag_clear(&cookie->stores, page->index,
156 FSCACHE_COOKIE_STORING_TAG);
David Howells285e7282009-11-19 18:11:29 +0000157 if (!radix_tree_tag_get(&cookie->stores, page->index,
158 FSCACHE_COOKIE_PENDING_TAG)) {
159 fscache_stat(&fscache_n_store_radix_deletes);
160 xpage = radix_tree_delete(&cookie->stores, page->index);
161 }
David Howells1bccf512009-11-19 18:11:25 +0000162 spin_unlock(&cookie->stores_lock);
163 wake_up_bit(&cookie->flags, 0);
164 }
165 spin_unlock(&object->lock);
166 if (xpage)
167 page_cache_release(xpage);
David Howellsb5108822009-04-03 16:42:39 +0100168}
169
170/*
171 * actually apply the changed attributes to a cache object
172 */
173static void fscache_attr_changed_op(struct fscache_operation *op)
174{
175 struct fscache_object *object = op->object;
David Howells440f0af2009-11-19 18:11:01 +0000176 int ret;
David Howellsb5108822009-04-03 16:42:39 +0100177
178 _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id);
179
180 fscache_stat(&fscache_n_attr_changed_calls);
181
David Howells8fb883f2013-09-21 00:09:31 +0100182 if (fscache_object_is_active(object)) {
David Howells52bd75f2009-11-19 18:11:08 +0000183 fscache_stat(&fscache_n_cop_attr_changed);
David Howells440f0af2009-11-19 18:11:01 +0000184 ret = object->cache->ops->attr_changed(object);
David Howells52bd75f2009-11-19 18:11:08 +0000185 fscache_stat_d(&fscache_n_cop_attr_changed);
David Howells440f0af2009-11-19 18:11:01 +0000186 if (ret < 0)
187 fscache_abort_object(object);
188 }
David Howellsb5108822009-04-03 16:42:39 +0100189
David Howells1f372df2012-12-13 20:03:13 +0000190 fscache_op_complete(op, true);
David Howellsb5108822009-04-03 16:42:39 +0100191 _leave("");
192}
193
194/*
195 * notification that the attributes on an object have changed
196 */
197int __fscache_attr_changed(struct fscache_cookie *cookie)
198{
199 struct fscache_operation *op;
200 struct fscache_object *object;
Milosz Tanski3e1199d2014-08-13 12:58:26 -0400201 bool wake_cookie = false;
David Howellsb5108822009-04-03 16:42:39 +0100202
203 _enter("%p", cookie);
204
205 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
206
207 fscache_stat(&fscache_n_attr_changed);
208
209 op = kzalloc(sizeof(*op), GFP_KERNEL);
210 if (!op) {
211 fscache_stat(&fscache_n_attr_changed_nomem);
212 _leave(" = -ENOMEM");
213 return -ENOMEM;
214 }
215
David Howellsd3b97ca2015-02-24 10:05:29 +0000216 fscache_operation_init(op, fscache_attr_changed_op, NULL, NULL);
David Howells8fb883f2013-09-21 00:09:31 +0100217 op->flags = FSCACHE_OP_ASYNC |
218 (1 << FSCACHE_OP_EXCLUSIVE) |
219 (1 << FSCACHE_OP_UNUSE_COOKIE);
David Howellsb5108822009-04-03 16:42:39 +0100220
221 spin_lock(&cookie->lock);
222
David Howells94d30ae2013-09-21 00:09:31 +0100223 if (!fscache_cookie_enabled(cookie) ||
224 hlist_empty(&cookie->backing_objects))
David Howellsb5108822009-04-03 16:42:39 +0100225 goto nobufs;
226 object = hlist_entry(cookie->backing_objects.first,
227 struct fscache_object, cookie_link);
228
David Howells8fb883f2013-09-21 00:09:31 +0100229 __fscache_use_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +0100230 if (fscache_submit_exclusive_op(object, op) < 0)
Milosz Tanski3e1199d2014-08-13 12:58:26 -0400231 goto nobufs_dec;
David Howellsb5108822009-04-03 16:42:39 +0100232 spin_unlock(&cookie->lock);
233 fscache_stat(&fscache_n_attr_changed_ok);
234 fscache_put_operation(op);
235 _leave(" = 0");
236 return 0;
237
Milosz Tanski3e1199d2014-08-13 12:58:26 -0400238nobufs_dec:
David Howells8fb883f2013-09-21 00:09:31 +0100239 wake_cookie = __fscache_unuse_cookie(cookie);
Milosz Tanski3e1199d2014-08-13 12:58:26 -0400240nobufs:
David Howellsb5108822009-04-03 16:42:39 +0100241 spin_unlock(&cookie->lock);
David Howellsa39caad2015-02-25 14:22:40 +0000242 fscache_put_operation(op);
David Howells8fb883f2013-09-21 00:09:31 +0100243 if (wake_cookie)
244 __fscache_wake_unused_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +0100245 fscache_stat(&fscache_n_attr_changed_nobufs);
246 _leave(" = %d", -ENOBUFS);
247 return -ENOBUFS;
248}
249EXPORT_SYMBOL(__fscache_attr_changed);
250
251/*
David Howellsd3b97ca2015-02-24 10:05:29 +0000252 * Handle cancellation of a pending retrieval op
253 */
254static void fscache_do_cancel_retrieval(struct fscache_operation *_op)
255{
256 struct fscache_retrieval *op =
257 container_of(_op, struct fscache_retrieval, op);
258
259 atomic_set(&op->n_pages, 0);
260}
261
262/*
David Howellsb5108822009-04-03 16:42:39 +0100263 * release a retrieval op reference
264 */
265static void fscache_release_retrieval_op(struct fscache_operation *_op)
266{
267 struct fscache_retrieval *op =
268 container_of(_op, struct fscache_retrieval, op);
269
270 _enter("{OP%x}", op->op.debug_id);
271
David Howells4a471322015-02-24 10:05:29 +0000272 ASSERTIFCMP(op->op.state != FSCACHE_OP_ST_INITIALISED,
273 atomic_read(&op->n_pages), ==, 0);
David Howells9f105232012-12-20 21:52:35 +0000274
David Howellsb5108822009-04-03 16:42:39 +0100275 fscache_hist(fscache_retrieval_histogram, op->start_time);
276 if (op->context)
David Howells4a471322015-02-24 10:05:29 +0000277 fscache_put_context(op->cookie, op->context);
David Howellsb5108822009-04-03 16:42:39 +0100278
279 _leave("");
280}
281
282/*
283 * allocate a retrieval op
284 */
285static struct fscache_retrieval *fscache_alloc_retrieval(
David Howells13627292013-05-10 19:50:26 +0100286 struct fscache_cookie *cookie,
David Howellsb5108822009-04-03 16:42:39 +0100287 struct address_space *mapping,
288 fscache_rw_complete_t end_io_func,
289 void *context)
290{
291 struct fscache_retrieval *op;
292
293 /* allocate a retrieval operation and attempt to submit it */
294 op = kzalloc(sizeof(*op), GFP_NOIO);
295 if (!op) {
296 fscache_stat(&fscache_n_retrievals_nomem);
297 return NULL;
298 }
299
David Howellsd3b97ca2015-02-24 10:05:29 +0000300 fscache_operation_init(&op->op, NULL,
301 fscache_do_cancel_retrieval,
302 fscache_release_retrieval_op);
David Howells13627292013-05-10 19:50:26 +0100303 op->op.flags = FSCACHE_OP_MYTHREAD |
304 (1UL << FSCACHE_OP_WAITING) |
305 (1UL << FSCACHE_OP_UNUSE_COOKIE);
David Howells4a471322015-02-24 10:05:29 +0000306 op->cookie = cookie;
David Howellsb5108822009-04-03 16:42:39 +0100307 op->mapping = mapping;
308 op->end_io_func = end_io_func;
309 op->context = context;
310 op->start_time = jiffies;
David Howellsb5108822009-04-03 16:42:39 +0100311 INIT_LIST_HEAD(&op->to_do);
David Howells4a471322015-02-24 10:05:29 +0000312
313 /* Pin the netfs read context in case we need to do the actual netfs
314 * read because we've encountered a cache read failure.
315 */
316 if (context)
317 fscache_get_context(op->cookie, context);
David Howellsb5108822009-04-03 16:42:39 +0100318 return op;
319}
320
321/*
322 * wait for a deferred lookup to complete
323 */
David Howellsda9803b2013-08-21 17:29:38 -0400324int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
David Howellsb5108822009-04-03 16:42:39 +0100325{
326 unsigned long jif;
327
328 _enter("");
329
330 if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
331 _leave(" = 0 [imm]");
332 return 0;
333 }
334
335 fscache_stat(&fscache_n_retrievals_wait);
336
337 jif = jiffies;
338 if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
David Howellsb5108822009-04-03 16:42:39 +0100339 TASK_INTERRUPTIBLE) != 0) {
340 fscache_stat(&fscache_n_retrievals_intr);
341 _leave(" = -ERESTARTSYS");
342 return -ERESTARTSYS;
343 }
344
345 ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
346
347 smp_rmb();
348 fscache_hist(fscache_retrieval_delay_histogram, jif);
349 _leave(" = 0 [dly]");
350 return 0;
351}
352
353/*
David Howells60d543c2009-11-19 18:11:45 +0000354 * wait for an object to become active (or dead)
355 */
David Howellsda9803b2013-08-21 17:29:38 -0400356int fscache_wait_for_operation_activation(struct fscache_object *object,
357 struct fscache_operation *op,
358 atomic_t *stat_op_waits,
David Howellsd3b97ca2015-02-24 10:05:29 +0000359 atomic_t *stat_object_dead)
David Howells60d543c2009-11-19 18:11:45 +0000360{
361 int ret;
362
David Howellsda9803b2013-08-21 17:29:38 -0400363 if (!test_bit(FSCACHE_OP_WAITING, &op->flags))
David Howells60d543c2009-11-19 18:11:45 +0000364 goto check_if_dead;
365
366 _debug(">>> WT");
David Howellsda9803b2013-08-21 17:29:38 -0400367 if (stat_op_waits)
368 fscache_stat(stat_op_waits);
369 if (wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
David Howells9c04caa2012-12-07 18:08:02 +0000370 TASK_INTERRUPTIBLE) != 0) {
David Howellsd3b97ca2015-02-24 10:05:29 +0000371 ret = fscache_cancel_op(op, false);
David Howells60d543c2009-11-19 18:11:45 +0000372 if (ret == 0)
373 return -ERESTARTSYS;
374
375 /* it's been removed from the pending queue by another party,
376 * so we should get to run shortly */
David Howellsda9803b2013-08-21 17:29:38 -0400377 wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
NeilBrown74316202014-07-07 15:16:04 +1000378 TASK_UNINTERRUPTIBLE);
David Howells60d543c2009-11-19 18:11:45 +0000379 }
380 _debug("<<< GO");
381
382check_if_dead:
David Howellsda9803b2013-08-21 17:29:38 -0400383 if (op->state == FSCACHE_OP_ST_CANCELLED) {
384 if (stat_object_dead)
385 fscache_stat(stat_object_dead);
David Howells9f105232012-12-20 21:52:35 +0000386 _leave(" = -ENOBUFS [cancelled]");
387 return -ENOBUFS;
388 }
David Howells87021522015-02-24 10:52:51 +0000389 if (unlikely(fscache_object_is_dying(object) ||
390 fscache_cache_is_broken(object))) {
391 enum fscache_operation_state state = op->state;
David Howellsd3b97ca2015-02-24 10:05:29 +0000392 fscache_cancel_op(op, true);
David Howellsda9803b2013-08-21 17:29:38 -0400393 if (stat_object_dead)
394 fscache_stat(stat_object_dead);
David Howells87021522015-02-24 10:52:51 +0000395 _leave(" = -ENOBUFS [obj dead %d]", state);
David Howells60d543c2009-11-19 18:11:45 +0000396 return -ENOBUFS;
397 }
398 return 0;
399}
400
401/*
David Howellsb5108822009-04-03 16:42:39 +0100402 * read a page from the cache or allocate a block in which to store it
403 * - we return:
404 * -ENOMEM - out of memory, nothing done
405 * -ERESTARTSYS - interrupted
406 * -ENOBUFS - no backing object available in which to cache the block
407 * -ENODATA - no data available in the backing object for this block
408 * 0 - dispatched a read - it'll call end_io_func() when finished
409 */
410int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
411 struct page *page,
412 fscache_rw_complete_t end_io_func,
413 void *context,
414 gfp_t gfp)
415{
416 struct fscache_retrieval *op;
417 struct fscache_object *object;
David Howells8fb883f2013-09-21 00:09:31 +0100418 bool wake_cookie = false;
David Howellsb5108822009-04-03 16:42:39 +0100419 int ret;
420
421 _enter("%p,%p,,,", cookie, page);
422
423 fscache_stat(&fscache_n_retrievals);
424
425 if (hlist_empty(&cookie->backing_objects))
426 goto nobufs;
427
David Howellsef778e72012-12-20 21:52:36 +0000428 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
429 _leave(" = -ENOBUFS [invalidating]");
430 return -ENOBUFS;
431 }
432
David Howellsb5108822009-04-03 16:42:39 +0100433 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
434 ASSERTCMP(page, !=, NULL);
435
436 if (fscache_wait_for_deferred_lookup(cookie) < 0)
437 return -ERESTARTSYS;
438
David Howells13627292013-05-10 19:50:26 +0100439 op = fscache_alloc_retrieval(cookie, page->mapping,
David Howells94d30ae2013-09-21 00:09:31 +0100440 end_io_func, context);
David Howellsb5108822009-04-03 16:42:39 +0100441 if (!op) {
442 _leave(" = -ENOMEM");
443 return -ENOMEM;
444 }
David Howells1bb4b7f92013-05-21 13:44:15 +0100445 atomic_set(&op->n_pages, 1);
David Howellsb5108822009-04-03 16:42:39 +0100446
447 spin_lock(&cookie->lock);
448
David Howells94d30ae2013-09-21 00:09:31 +0100449 if (!fscache_cookie_enabled(cookie) ||
450 hlist_empty(&cookie->backing_objects))
David Howellsb5108822009-04-03 16:42:39 +0100451 goto nobufs_unlock;
452 object = hlist_entry(cookie->backing_objects.first,
453 struct fscache_object, cookie_link);
454
David Howellscaaef692013-05-10 19:50:26 +0100455 ASSERT(test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags));
David Howellsb5108822009-04-03 16:42:39 +0100456
David Howells8fb883f2013-09-21 00:09:31 +0100457 __fscache_use_cookie(cookie);
David Howells4fbf4292009-11-19 18:11:04 +0000458 atomic_inc(&object->n_reads);
David Howells9f105232012-12-20 21:52:35 +0000459 __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
David Howells4fbf4292009-11-19 18:11:04 +0000460
David Howellsb5108822009-04-03 16:42:39 +0100461 if (fscache_submit_op(object, &op->op) < 0)
David Howells9f105232012-12-20 21:52:35 +0000462 goto nobufs_unlock_dec;
David Howellsb5108822009-04-03 16:42:39 +0100463 spin_unlock(&cookie->lock);
464
465 fscache_stat(&fscache_n_retrieval_ops);
466
David Howellsb5108822009-04-03 16:42:39 +0100467 /* we wait for the operation to become active, and then process it
468 * *here*, in this thread, and not in the thread pool */
David Howellsda9803b2013-08-21 17:29:38 -0400469 ret = fscache_wait_for_operation_activation(
470 object, &op->op,
David Howells60d543c2009-11-19 18:11:45 +0000471 __fscache_stat(&fscache_n_retrieval_op_waits),
David Howellsd3b97ca2015-02-24 10:05:29 +0000472 __fscache_stat(&fscache_n_retrievals_object_dead));
David Howells60d543c2009-11-19 18:11:45 +0000473 if (ret < 0)
474 goto error;
David Howellsb5108822009-04-03 16:42:39 +0100475
476 /* ask the cache to honour the operation */
477 if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
David Howells52bd75f2009-11-19 18:11:08 +0000478 fscache_stat(&fscache_n_cop_allocate_page);
David Howellsb5108822009-04-03 16:42:39 +0100479 ret = object->cache->ops->allocate_page(op, page, gfp);
David Howells52bd75f2009-11-19 18:11:08 +0000480 fscache_stat_d(&fscache_n_cop_allocate_page);
David Howellsb5108822009-04-03 16:42:39 +0100481 if (ret == 0)
482 ret = -ENODATA;
483 } else {
David Howells52bd75f2009-11-19 18:11:08 +0000484 fscache_stat(&fscache_n_cop_read_or_alloc_page);
David Howellsb5108822009-04-03 16:42:39 +0100485 ret = object->cache->ops->read_or_alloc_page(op, page, gfp);
David Howells52bd75f2009-11-19 18:11:08 +0000486 fscache_stat_d(&fscache_n_cop_read_or_alloc_page);
David Howellsb5108822009-04-03 16:42:39 +0100487 }
488
David Howells5753c442009-11-19 18:11:19 +0000489error:
David Howellsb5108822009-04-03 16:42:39 +0100490 if (ret == -ENOMEM)
491 fscache_stat(&fscache_n_retrievals_nomem);
492 else if (ret == -ERESTARTSYS)
493 fscache_stat(&fscache_n_retrievals_intr);
494 else if (ret == -ENODATA)
495 fscache_stat(&fscache_n_retrievals_nodata);
496 else if (ret < 0)
497 fscache_stat(&fscache_n_retrievals_nobufs);
498 else
499 fscache_stat(&fscache_n_retrievals_ok);
500
501 fscache_put_retrieval(op);
502 _leave(" = %d", ret);
503 return ret;
504
David Howells9f105232012-12-20 21:52:35 +0000505nobufs_unlock_dec:
506 atomic_dec(&object->n_reads);
David Howells8fb883f2013-09-21 00:09:31 +0100507 wake_cookie = __fscache_unuse_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +0100508nobufs_unlock:
509 spin_unlock(&cookie->lock);
David Howells8fb883f2013-09-21 00:09:31 +0100510 if (wake_cookie)
511 __fscache_wake_unused_cookie(cookie);
David Howellsa39caad2015-02-25 14:22:40 +0000512 fscache_put_retrieval(op);
David Howellsb5108822009-04-03 16:42:39 +0100513nobufs:
514 fscache_stat(&fscache_n_retrievals_nobufs);
515 _leave(" = -ENOBUFS");
516 return -ENOBUFS;
517}
518EXPORT_SYMBOL(__fscache_read_or_alloc_page);
519
520/*
521 * read a list of page from the cache or allocate a block in which to store
522 * them
523 * - we return:
524 * -ENOMEM - out of memory, some pages may be being read
525 * -ERESTARTSYS - interrupted, some pages may be being read
526 * -ENOBUFS - no backing object or space available in which to cache any
527 * pages not being read
528 * -ENODATA - no data available in the backing object for some or all of
529 * the pages
530 * 0 - dispatched a read on all pages
531 *
532 * end_io_func() will be called for each page read from the cache as it is
533 * finishes being read
534 *
535 * any pages for which a read is dispatched will be removed from pages and
536 * nr_pages
537 */
538int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
539 struct address_space *mapping,
540 struct list_head *pages,
541 unsigned *nr_pages,
542 fscache_rw_complete_t end_io_func,
543 void *context,
544 gfp_t gfp)
545{
David Howellsb5108822009-04-03 16:42:39 +0100546 struct fscache_retrieval *op;
547 struct fscache_object *object;
David Howells8fb883f2013-09-21 00:09:31 +0100548 bool wake_cookie = false;
David Howellsb5108822009-04-03 16:42:39 +0100549 int ret;
550
551 _enter("%p,,%d,,,", cookie, *nr_pages);
552
553 fscache_stat(&fscache_n_retrievals);
554
555 if (hlist_empty(&cookie->backing_objects))
556 goto nobufs;
557
David Howellsef778e72012-12-20 21:52:36 +0000558 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
559 _leave(" = -ENOBUFS [invalidating]");
560 return -ENOBUFS;
561 }
562
David Howellsb5108822009-04-03 16:42:39 +0100563 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
564 ASSERTCMP(*nr_pages, >, 0);
565 ASSERT(!list_empty(pages));
566
567 if (fscache_wait_for_deferred_lookup(cookie) < 0)
568 return -ERESTARTSYS;
569
David Howells13627292013-05-10 19:50:26 +0100570 op = fscache_alloc_retrieval(cookie, mapping, end_io_func, context);
David Howellsb5108822009-04-03 16:42:39 +0100571 if (!op)
572 return -ENOMEM;
David Howells1bb4b7f92013-05-21 13:44:15 +0100573 atomic_set(&op->n_pages, *nr_pages);
David Howellsb5108822009-04-03 16:42:39 +0100574
575 spin_lock(&cookie->lock);
576
David Howells94d30ae2013-09-21 00:09:31 +0100577 if (!fscache_cookie_enabled(cookie) ||
578 hlist_empty(&cookie->backing_objects))
David Howellsb5108822009-04-03 16:42:39 +0100579 goto nobufs_unlock;
580 object = hlist_entry(cookie->backing_objects.first,
581 struct fscache_object, cookie_link);
582
David Howells8fb883f2013-09-21 00:09:31 +0100583 __fscache_use_cookie(cookie);
David Howells4fbf4292009-11-19 18:11:04 +0000584 atomic_inc(&object->n_reads);
David Howells9f105232012-12-20 21:52:35 +0000585 __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
David Howells4fbf4292009-11-19 18:11:04 +0000586
David Howellsb5108822009-04-03 16:42:39 +0100587 if (fscache_submit_op(object, &op->op) < 0)
David Howells9f105232012-12-20 21:52:35 +0000588 goto nobufs_unlock_dec;
David Howellsb5108822009-04-03 16:42:39 +0100589 spin_unlock(&cookie->lock);
590
591 fscache_stat(&fscache_n_retrieval_ops);
592
David Howellsb5108822009-04-03 16:42:39 +0100593 /* we wait for the operation to become active, and then process it
594 * *here*, in this thread, and not in the thread pool */
David Howellsda9803b2013-08-21 17:29:38 -0400595 ret = fscache_wait_for_operation_activation(
596 object, &op->op,
David Howells60d543c2009-11-19 18:11:45 +0000597 __fscache_stat(&fscache_n_retrieval_op_waits),
David Howellsd3b97ca2015-02-24 10:05:29 +0000598 __fscache_stat(&fscache_n_retrievals_object_dead));
David Howells60d543c2009-11-19 18:11:45 +0000599 if (ret < 0)
600 goto error;
David Howellsb5108822009-04-03 16:42:39 +0100601
602 /* ask the cache to honour the operation */
David Howells52bd75f2009-11-19 18:11:08 +0000603 if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) {
604 fscache_stat(&fscache_n_cop_allocate_pages);
605 ret = object->cache->ops->allocate_pages(
606 op, pages, nr_pages, gfp);
607 fscache_stat_d(&fscache_n_cop_allocate_pages);
608 } else {
609 fscache_stat(&fscache_n_cop_read_or_alloc_pages);
610 ret = object->cache->ops->read_or_alloc_pages(
611 op, pages, nr_pages, gfp);
612 fscache_stat_d(&fscache_n_cop_read_or_alloc_pages);
613 }
David Howellsb5108822009-04-03 16:42:39 +0100614
David Howells5753c442009-11-19 18:11:19 +0000615error:
David Howellsb5108822009-04-03 16:42:39 +0100616 if (ret == -ENOMEM)
617 fscache_stat(&fscache_n_retrievals_nomem);
618 else if (ret == -ERESTARTSYS)
619 fscache_stat(&fscache_n_retrievals_intr);
620 else if (ret == -ENODATA)
621 fscache_stat(&fscache_n_retrievals_nodata);
622 else if (ret < 0)
623 fscache_stat(&fscache_n_retrievals_nobufs);
624 else
625 fscache_stat(&fscache_n_retrievals_ok);
626
627 fscache_put_retrieval(op);
628 _leave(" = %d", ret);
629 return ret;
630
David Howells9f105232012-12-20 21:52:35 +0000631nobufs_unlock_dec:
632 atomic_dec(&object->n_reads);
David Howells8fb883f2013-09-21 00:09:31 +0100633 wake_cookie = __fscache_unuse_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +0100634nobufs_unlock:
635 spin_unlock(&cookie->lock);
David Howellsa39caad2015-02-25 14:22:40 +0000636 fscache_put_retrieval(op);
David Howells8fb883f2013-09-21 00:09:31 +0100637 if (wake_cookie)
638 __fscache_wake_unused_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +0100639nobufs:
640 fscache_stat(&fscache_n_retrievals_nobufs);
641 _leave(" = -ENOBUFS");
642 return -ENOBUFS;
643}
644EXPORT_SYMBOL(__fscache_read_or_alloc_pages);
645
646/*
647 * allocate a block in the cache on which to store a page
648 * - we return:
649 * -ENOMEM - out of memory, nothing done
650 * -ERESTARTSYS - interrupted
651 * -ENOBUFS - no backing object available in which to cache the block
652 * 0 - block allocated
653 */
654int __fscache_alloc_page(struct fscache_cookie *cookie,
655 struct page *page,
656 gfp_t gfp)
657{
658 struct fscache_retrieval *op;
659 struct fscache_object *object;
David Howells8fb883f2013-09-21 00:09:31 +0100660 bool wake_cookie = false;
David Howellsb5108822009-04-03 16:42:39 +0100661 int ret;
662
663 _enter("%p,%p,,,", cookie, page);
664
665 fscache_stat(&fscache_n_allocs);
666
667 if (hlist_empty(&cookie->backing_objects))
668 goto nobufs;
669
670 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
671 ASSERTCMP(page, !=, NULL);
672
David Howellsef778e72012-12-20 21:52:36 +0000673 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
674 _leave(" = -ENOBUFS [invalidating]");
675 return -ENOBUFS;
676 }
677
David Howellsb5108822009-04-03 16:42:39 +0100678 if (fscache_wait_for_deferred_lookup(cookie) < 0)
679 return -ERESTARTSYS;
680
David Howells13627292013-05-10 19:50:26 +0100681 op = fscache_alloc_retrieval(cookie, page->mapping, NULL, NULL);
David Howellsb5108822009-04-03 16:42:39 +0100682 if (!op)
683 return -ENOMEM;
David Howells1bb4b7f92013-05-21 13:44:15 +0100684 atomic_set(&op->n_pages, 1);
David Howellsb5108822009-04-03 16:42:39 +0100685
686 spin_lock(&cookie->lock);
687
David Howells94d30ae2013-09-21 00:09:31 +0100688 if (!fscache_cookie_enabled(cookie) ||
689 hlist_empty(&cookie->backing_objects))
David Howellsb5108822009-04-03 16:42:39 +0100690 goto nobufs_unlock;
691 object = hlist_entry(cookie->backing_objects.first,
692 struct fscache_object, cookie_link);
693
David Howells8fb883f2013-09-21 00:09:31 +0100694 __fscache_use_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +0100695 if (fscache_submit_op(object, &op->op) < 0)
David Howells8fb883f2013-09-21 00:09:31 +0100696 goto nobufs_unlock_dec;
David Howellsb5108822009-04-03 16:42:39 +0100697 spin_unlock(&cookie->lock);
698
699 fscache_stat(&fscache_n_alloc_ops);
700
David Howellsda9803b2013-08-21 17:29:38 -0400701 ret = fscache_wait_for_operation_activation(
702 object, &op->op,
David Howells60d543c2009-11-19 18:11:45 +0000703 __fscache_stat(&fscache_n_alloc_op_waits),
David Howellsd3b97ca2015-02-24 10:05:29 +0000704 __fscache_stat(&fscache_n_allocs_object_dead));
David Howells60d543c2009-11-19 18:11:45 +0000705 if (ret < 0)
706 goto error;
David Howellsb5108822009-04-03 16:42:39 +0100707
708 /* ask the cache to honour the operation */
David Howells52bd75f2009-11-19 18:11:08 +0000709 fscache_stat(&fscache_n_cop_allocate_page);
David Howellsb5108822009-04-03 16:42:39 +0100710 ret = object->cache->ops->allocate_page(op, page, gfp);
David Howells52bd75f2009-11-19 18:11:08 +0000711 fscache_stat_d(&fscache_n_cop_allocate_page);
David Howellsb5108822009-04-03 16:42:39 +0100712
David Howells5753c442009-11-19 18:11:19 +0000713error:
714 if (ret == -ERESTARTSYS)
715 fscache_stat(&fscache_n_allocs_intr);
716 else if (ret < 0)
David Howellsb5108822009-04-03 16:42:39 +0100717 fscache_stat(&fscache_n_allocs_nobufs);
718 else
719 fscache_stat(&fscache_n_allocs_ok);
720
721 fscache_put_retrieval(op);
722 _leave(" = %d", ret);
723 return ret;
724
David Howells8fb883f2013-09-21 00:09:31 +0100725nobufs_unlock_dec:
726 wake_cookie = __fscache_unuse_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +0100727nobufs_unlock:
728 spin_unlock(&cookie->lock);
David Howellsa39caad2015-02-25 14:22:40 +0000729 fscache_put_retrieval(op);
David Howells8fb883f2013-09-21 00:09:31 +0100730 if (wake_cookie)
731 __fscache_wake_unused_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +0100732nobufs:
733 fscache_stat(&fscache_n_allocs_nobufs);
734 _leave(" = -ENOBUFS");
735 return -ENOBUFS;
736}
737EXPORT_SYMBOL(__fscache_alloc_page);
738
739/*
Milosz Tanski5a6f2822013-08-21 17:30:11 -0400740 * Unmark pages allocate in the readahead code path (via:
741 * fscache_readpages_or_alloc) after delegating to the base filesystem
742 */
743void __fscache_readpages_cancel(struct fscache_cookie *cookie,
744 struct list_head *pages)
745{
746 struct page *page;
747
748 list_for_each_entry(page, pages, lru) {
749 if (PageFsCache(page))
750 __fscache_uncache_page(cookie, page);
751 }
752}
753EXPORT_SYMBOL(__fscache_readpages_cancel);
754
755/*
David Howellsb5108822009-04-03 16:42:39 +0100756 * release a write op reference
757 */
758static void fscache_release_write_op(struct fscache_operation *_op)
759{
760 _enter("{OP%x}", _op->debug_id);
761}
762
763/*
764 * perform the background storage of a page into the cache
765 */
766static void fscache_write_op(struct fscache_operation *_op)
767{
768 struct fscache_storage *op =
769 container_of(_op, struct fscache_storage, op);
770 struct fscache_object *object = op->op.object;
David Howells1bccf512009-11-19 18:11:25 +0000771 struct fscache_cookie *cookie;
David Howellsb5108822009-04-03 16:42:39 +0100772 struct page *page;
773 unsigned n;
774 void *results[1];
775 int ret;
776
777 _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage));
778
David Howellsb5108822009-04-03 16:42:39 +0100779 spin_lock(&object->lock);
David Howells1bccf512009-11-19 18:11:25 +0000780 cookie = object->cookie;
David Howellsb5108822009-04-03 16:42:39 +0100781
David Howells7ef001e2012-12-07 10:41:26 +0000782 if (!fscache_object_is_active(object)) {
783 /* If we get here, then the on-disk cache object likely longer
784 * exists, so we should just cancel this write operation.
785 */
David Howellsb5108822009-04-03 16:42:39 +0100786 spin_unlock(&object->lock);
David Howells1f372df2012-12-13 20:03:13 +0000787 fscache_op_complete(&op->op, false);
David Howells7ef001e2012-12-07 10:41:26 +0000788 _leave(" [inactive]");
789 return;
790 }
791
792 if (!cookie) {
793 /* If we get here, then the cookie belonging to the object was
794 * detached, probably by the cookie being withdrawn due to
795 * memory pressure, which means that the pages we might write
796 * to the cache from no longer exist - therefore, we can just
797 * cancel this write operation.
798 */
799 spin_unlock(&object->lock);
David Howells1f372df2012-12-13 20:03:13 +0000800 fscache_op_complete(&op->op, false);
David Howellscaaef692013-05-10 19:50:26 +0100801 _leave(" [cancel] op{f=%lx s=%u} obj{s=%s f=%lx}",
802 _op->flags, _op->state, object->state->short_name,
803 object->flags);
David Howellsb5108822009-04-03 16:42:39 +0100804 return;
805 }
806
David Howells1bccf512009-11-19 18:11:25 +0000807 spin_lock(&cookie->stores_lock);
808
David Howellsb5108822009-04-03 16:42:39 +0100809 fscache_stat(&fscache_n_store_calls);
810
811 /* find a page to store */
812 page = NULL;
813 n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
814 FSCACHE_COOKIE_PENDING_TAG);
815 if (n != 1)
816 goto superseded;
817 page = results[0];
818 _debug("gang %d [%lx]", n, page->index);
David Howells1bccf512009-11-19 18:11:25 +0000819 if (page->index > op->store_limit) {
820 fscache_stat(&fscache_n_store_pages_over_limit);
David Howellsb5108822009-04-03 16:42:39 +0100821 goto superseded;
David Howells1bccf512009-11-19 18:11:25 +0000822 }
David Howellsb5108822009-04-03 16:42:39 +0100823
Dan Carpenter08a66852010-06-01 20:58:22 +0100824 radix_tree_tag_set(&cookie->stores, page->index,
825 FSCACHE_COOKIE_STORING_TAG);
826 radix_tree_tag_clear(&cookie->stores, page->index,
827 FSCACHE_COOKIE_PENDING_TAG);
David Howellsb5108822009-04-03 16:42:39 +0100828
David Howells1bccf512009-11-19 18:11:25 +0000829 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100830 spin_unlock(&object->lock);
David Howellsb5108822009-04-03 16:42:39 +0100831
Dan Carpenter08a66852010-06-01 20:58:22 +0100832 fscache_stat(&fscache_n_store_pages);
833 fscache_stat(&fscache_n_cop_write_page);
834 ret = object->cache->ops->write_page(op, page);
835 fscache_stat_d(&fscache_n_cop_write_page);
Dan Carpenter08a66852010-06-01 20:58:22 +0100836 fscache_end_page_write(object, page);
837 if (ret < 0) {
Dan Carpenter08a66852010-06-01 20:58:22 +0100838 fscache_abort_object(object);
David Howells1f372df2012-12-13 20:03:13 +0000839 fscache_op_complete(&op->op, true);
Dan Carpenter08a66852010-06-01 20:58:22 +0100840 } else {
841 fscache_enqueue_operation(&op->op);
David Howellsb5108822009-04-03 16:42:39 +0100842 }
843
844 _leave("");
845 return;
846
847superseded:
848 /* this writer is going away and there aren't any more things to
849 * write */
850 _debug("cease");
David Howells1bccf512009-11-19 18:11:25 +0000851 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100852 clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
853 spin_unlock(&object->lock);
David Howells1f372df2012-12-13 20:03:13 +0000854 fscache_op_complete(&op->op, true);
David Howellsb5108822009-04-03 16:42:39 +0100855 _leave("");
856}
857
858/*
David Howellsef778e72012-12-20 21:52:36 +0000859 * Clear the pages pending writing for invalidation
860 */
861void fscache_invalidate_writes(struct fscache_cookie *cookie)
862{
863 struct page *page;
864 void *results[16];
865 int n, i;
866
867 _enter("");
868
Sebastian Andrzej Siewioree8be572013-05-10 19:50:24 +0100869 for (;;) {
870 spin_lock(&cookie->stores_lock);
871 n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
872 ARRAY_SIZE(results),
873 FSCACHE_COOKIE_PENDING_TAG);
874 if (n == 0) {
875 spin_unlock(&cookie->stores_lock);
876 break;
877 }
878
David Howellsef778e72012-12-20 21:52:36 +0000879 for (i = n - 1; i >= 0; i--) {
880 page = results[i];
881 radix_tree_delete(&cookie->stores, page->index);
882 }
883
884 spin_unlock(&cookie->stores_lock);
885
886 for (i = n - 1; i >= 0; i--)
887 page_cache_release(results[i]);
888 }
889
David Howellsef778e72012-12-20 21:52:36 +0000890 _leave("");
891}
892
893/*
David Howellsb5108822009-04-03 16:42:39 +0100894 * request a page be stored in the cache
895 * - returns:
896 * -ENOMEM - out of memory, nothing done
897 * -ENOBUFS - no backing object available in which to cache the page
898 * 0 - dispatched a write - it'll call end_io_func() when finished
899 *
900 * if the cookie still has a backing object at this point, that object can be
901 * in one of a few states with respect to storage processing:
902 *
903 * (1) negative lookup, object not yet created (FSCACHE_COOKIE_CREATING is
904 * set)
905 *
David Howellscaaef692013-05-10 19:50:26 +0100906 * (a) no writes yet
David Howellsb5108822009-04-03 16:42:39 +0100907 *
908 * (b) writes deferred till post-creation (mark page for writing and
909 * return immediately)
910 *
911 * (2) negative lookup, object created, initial fill being made from netfs
David Howellsb5108822009-04-03 16:42:39 +0100912 *
913 * (a) fill point not yet reached this page (mark page for writing and
914 * return)
915 *
916 * (b) fill point passed this page (queue op to store this page)
917 *
918 * (3) object extant (queue op to store this page)
919 *
920 * any other state is invalid
921 */
922int __fscache_write_page(struct fscache_cookie *cookie,
923 struct page *page,
924 gfp_t gfp)
925{
926 struct fscache_storage *op;
927 struct fscache_object *object;
David Howells8fb883f2013-09-21 00:09:31 +0100928 bool wake_cookie = false;
David Howellsb5108822009-04-03 16:42:39 +0100929 int ret;
930
931 _enter("%p,%x,", cookie, (u32) page->flags);
932
933 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
934 ASSERT(PageFsCache(page));
935
936 fscache_stat(&fscache_n_stores);
937
David Howellsef778e72012-12-20 21:52:36 +0000938 if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
939 _leave(" = -ENOBUFS [invalidating]");
940 return -ENOBUFS;
941 }
942
David Howells5f4f9f42012-12-20 21:52:33 +0000943 op = kzalloc(sizeof(*op), GFP_NOIO | __GFP_NOMEMALLOC | __GFP_NORETRY);
David Howellsb5108822009-04-03 16:42:39 +0100944 if (!op)
945 goto nomem;
946
David Howellsd3b97ca2015-02-24 10:05:29 +0000947 fscache_operation_init(&op->op, fscache_write_op, NULL,
Tejun Heo8af7c122010-07-20 22:09:01 +0200948 fscache_release_write_op);
David Howells13627292013-05-10 19:50:26 +0100949 op->op.flags = FSCACHE_OP_ASYNC |
950 (1 << FSCACHE_OP_WAITING) |
951 (1 << FSCACHE_OP_UNUSE_COOKIE);
David Howellsb5108822009-04-03 16:42:39 +0100952
Jan Kara5e4c0d972013-09-11 14:26:05 -0700953 ret = radix_tree_maybe_preload(gfp & ~__GFP_HIGHMEM);
David Howellsb5108822009-04-03 16:42:39 +0100954 if (ret < 0)
955 goto nomem_free;
956
957 ret = -ENOBUFS;
958 spin_lock(&cookie->lock);
959
David Howells94d30ae2013-09-21 00:09:31 +0100960 if (!fscache_cookie_enabled(cookie) ||
961 hlist_empty(&cookie->backing_objects))
David Howellsb5108822009-04-03 16:42:39 +0100962 goto nobufs;
963 object = hlist_entry(cookie->backing_objects.first,
964 struct fscache_object, cookie_link);
965 if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
966 goto nobufs;
967
968 /* add the page to the pending-storage radix tree on the backing
969 * object */
970 spin_lock(&object->lock);
David Howells1bccf512009-11-19 18:11:25 +0000971 spin_lock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100972
973 _debug("store limit %llx", (unsigned long long) object->store_limit);
974
975 ret = radix_tree_insert(&cookie->stores, page->index, page);
976 if (ret < 0) {
977 if (ret == -EEXIST)
978 goto already_queued;
979 _debug("insert failed %d", ret);
980 goto nobufs_unlock_obj;
981 }
982
983 radix_tree_tag_set(&cookie->stores, page->index,
984 FSCACHE_COOKIE_PENDING_TAG);
985 page_cache_get(page);
986
987 /* we only want one writer at a time, but we do need to queue new
988 * writers after exclusive ops */
989 if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags))
990 goto already_pending;
991
David Howells1bccf512009-11-19 18:11:25 +0000992 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +0100993 spin_unlock(&object->lock);
994
995 op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
996 op->store_limit = object->store_limit;
997
David Howells8fb883f2013-09-21 00:09:31 +0100998 __fscache_use_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +0100999 if (fscache_submit_op(object, &op->op) < 0)
1000 goto submit_failed;
1001
1002 spin_unlock(&cookie->lock);
1003 radix_tree_preload_end();
1004 fscache_stat(&fscache_n_store_ops);
1005 fscache_stat(&fscache_n_stores_ok);
1006
Tejun Heo8af7c122010-07-20 22:09:01 +02001007 /* the work queue now carries its own ref on the object */
David Howellsb5108822009-04-03 16:42:39 +01001008 fscache_put_operation(&op->op);
1009 _leave(" = 0");
1010 return 0;
1011
1012already_queued:
1013 fscache_stat(&fscache_n_stores_again);
1014already_pending:
David Howells1bccf512009-11-19 18:11:25 +00001015 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +01001016 spin_unlock(&object->lock);
1017 spin_unlock(&cookie->lock);
1018 radix_tree_preload_end();
David Howellsa39caad2015-02-25 14:22:40 +00001019 fscache_put_operation(&op->op);
David Howellsb5108822009-04-03 16:42:39 +01001020 fscache_stat(&fscache_n_stores_ok);
1021 _leave(" = 0");
1022 return 0;
1023
1024submit_failed:
David Howells1bccf512009-11-19 18:11:25 +00001025 spin_lock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +01001026 radix_tree_delete(&cookie->stores, page->index);
David Howells1bccf512009-11-19 18:11:25 +00001027 spin_unlock(&cookie->stores_lock);
David Howells8fb883f2013-09-21 00:09:31 +01001028 wake_cookie = __fscache_unuse_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +01001029 page_cache_release(page);
1030 ret = -ENOBUFS;
1031 goto nobufs;
1032
1033nobufs_unlock_obj:
Dan Carpenter1147d0f2010-03-23 14:48:37 +00001034 spin_unlock(&cookie->stores_lock);
David Howellsb5108822009-04-03 16:42:39 +01001035 spin_unlock(&object->lock);
1036nobufs:
1037 spin_unlock(&cookie->lock);
1038 radix_tree_preload_end();
David Howellsa39caad2015-02-25 14:22:40 +00001039 fscache_put_operation(&op->op);
David Howells8fb883f2013-09-21 00:09:31 +01001040 if (wake_cookie)
1041 __fscache_wake_unused_cookie(cookie);
David Howellsb5108822009-04-03 16:42:39 +01001042 fscache_stat(&fscache_n_stores_nobufs);
1043 _leave(" = -ENOBUFS");
1044 return -ENOBUFS;
1045
1046nomem_free:
David Howellsa39caad2015-02-25 14:22:40 +00001047 fscache_put_operation(&op->op);
David Howellsb5108822009-04-03 16:42:39 +01001048nomem:
1049 fscache_stat(&fscache_n_stores_oom);
1050 _leave(" = -ENOMEM");
1051 return -ENOMEM;
1052}
1053EXPORT_SYMBOL(__fscache_write_page);
1054
1055/*
1056 * remove a page from the cache
1057 */
1058void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page)
1059{
1060 struct fscache_object *object;
1061
1062 _enter(",%p", page);
1063
1064 ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
1065 ASSERTCMP(page, !=, NULL);
1066
1067 fscache_stat(&fscache_n_uncaches);
1068
1069 /* cache withdrawal may beat us to it */
1070 if (!PageFsCache(page))
1071 goto done;
1072
1073 /* get the object */
1074 spin_lock(&cookie->lock);
1075
1076 if (hlist_empty(&cookie->backing_objects)) {
1077 ClearPageFsCache(page);
1078 goto done_unlock;
1079 }
1080
1081 object = hlist_entry(cookie->backing_objects.first,
1082 struct fscache_object, cookie_link);
1083
1084 /* there might now be stuff on disk we could read */
1085 clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
1086
1087 /* only invoke the cache backend if we managed to mark the page
1088 * uncached here; this deals with synchronisation vs withdrawal */
1089 if (TestClearPageFsCache(page) &&
1090 object->cache->ops->uncache_page) {
1091 /* the cache backend releases the cookie lock */
David Howells52bd75f2009-11-19 18:11:08 +00001092 fscache_stat(&fscache_n_cop_uncache_page);
David Howellsb5108822009-04-03 16:42:39 +01001093 object->cache->ops->uncache_page(object, page);
David Howells52bd75f2009-11-19 18:11:08 +00001094 fscache_stat_d(&fscache_n_cop_uncache_page);
David Howellsb5108822009-04-03 16:42:39 +01001095 goto done;
1096 }
1097
1098done_unlock:
1099 spin_unlock(&cookie->lock);
1100done:
1101 _leave("");
1102}
1103EXPORT_SYMBOL(__fscache_uncache_page);
1104
1105/**
David Howellsc4d6d8d2012-12-20 21:52:32 +00001106 * fscache_mark_page_cached - Mark a page as being cached
1107 * @op: The retrieval op pages are being marked for
1108 * @page: The page to be marked
1109 *
1110 * Mark a netfs page as being cached. After this is called, the netfs
1111 * must call fscache_uncache_page() to remove the mark.
1112 */
1113void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page)
1114{
1115 struct fscache_cookie *cookie = op->op.object->cookie;
1116
1117#ifdef CONFIG_FSCACHE_STATS
1118 atomic_inc(&fscache_n_marks);
1119#endif
1120
1121 _debug("- mark %p{%lx}", page, page->index);
1122 if (TestSetPageFsCache(page)) {
1123 static bool once_only;
1124 if (!once_only) {
1125 once_only = true;
Fabian Frederick36dfd112014-06-04 16:05:38 -07001126 pr_warn("Cookie type %s marked page %lx multiple times\n",
1127 cookie->def->name, page->index);
David Howellsc4d6d8d2012-12-20 21:52:32 +00001128 }
1129 }
1130
1131 if (cookie->def->mark_page_cached)
1132 cookie->def->mark_page_cached(cookie->netfs_data,
1133 op->mapping, page);
1134}
1135EXPORT_SYMBOL(fscache_mark_page_cached);
1136
1137/**
David Howellsb5108822009-04-03 16:42:39 +01001138 * fscache_mark_pages_cached - Mark pages as being cached
1139 * @op: The retrieval op pages are being marked for
1140 * @pagevec: The pages to be marked
1141 *
1142 * Mark a bunch of netfs pages as being cached. After this is called,
1143 * the netfs must call fscache_uncache_page() to remove the mark.
1144 */
1145void fscache_mark_pages_cached(struct fscache_retrieval *op,
1146 struct pagevec *pagevec)
1147{
David Howellsb5108822009-04-03 16:42:39 +01001148 unsigned long loop;
1149
David Howellsc4d6d8d2012-12-20 21:52:32 +00001150 for (loop = 0; loop < pagevec->nr; loop++)
1151 fscache_mark_page_cached(op, pagevec->pages[loop]);
David Howellsb5108822009-04-03 16:42:39 +01001152
David Howellsb5108822009-04-03 16:42:39 +01001153 pagevec_reinit(pagevec);
1154}
1155EXPORT_SYMBOL(fscache_mark_pages_cached);
David Howellsc902ce12011-07-07 12:19:48 +01001156
1157/*
1158 * Uncache all the pages in an inode that are marked PG_fscache, assuming them
1159 * to be associated with the given cookie.
1160 */
1161void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
1162 struct inode *inode)
1163{
1164 struct address_space *mapping = inode->i_mapping;
1165 struct pagevec pvec;
1166 pgoff_t next;
1167 int i;
1168
1169 _enter("%p,%p", cookie, inode);
1170
1171 if (!mapping || mapping->nrpages == 0) {
1172 _leave(" [no pages]");
1173 return;
1174 }
1175
1176 pagevec_init(&pvec, 0);
1177 next = 0;
Jan Beulichb307d462011-07-21 15:02:43 +01001178 do {
1179 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
1180 break;
David Howellsc902ce12011-07-07 12:19:48 +01001181 for (i = 0; i < pagevec_count(&pvec); i++) {
1182 struct page *page = pvec.pages[i];
Jan Beulichb307d462011-07-21 15:02:43 +01001183 next = page->index;
David Howellsc902ce12011-07-07 12:19:48 +01001184 if (PageFsCache(page)) {
1185 __fscache_wait_on_page_write(cookie, page);
1186 __fscache_uncache_page(cookie, page);
1187 }
1188 }
1189 pagevec_release(&pvec);
1190 cond_resched();
Jan Beulichb307d462011-07-21 15:02:43 +01001191 } while (++next);
David Howellsc902ce12011-07-07 12:19:48 +01001192
1193 _leave("");
1194}
1195EXPORT_SYMBOL(__fscache_uncache_all_inode_pages);