blob: 6935901bce380d8b436e2561ee0ec63ee9deff77 [file] [log] [blame]
David Howells952efe72009-04-03 16:42:39 +01001/* FS-Cache worker operation management routines
2 *
3 * Copyright (C) 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 * See Documentation/filesystems/caching/operations.txt
12 */
13
14#define FSCACHE_DEBUG_LEVEL OPERATION
15#include <linux/module.h>
David Howells440f0af2009-11-19 18:11:01 +000016#include <linux/seq_file.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090017#include <linux/slab.h>
David Howells952efe72009-04-03 16:42:39 +010018#include "internal.h"
19
20atomic_t fscache_op_debug_id;
21EXPORT_SYMBOL(fscache_op_debug_id);
22
23/**
24 * fscache_enqueue_operation - Enqueue an operation for processing
25 * @op: The operation to enqueue
26 *
27 * Enqueue an operation for processing by the FS-Cache thread pool.
28 *
29 * This will get its own ref on the object.
30 */
31void fscache_enqueue_operation(struct fscache_operation *op)
32{
33 _enter("{OBJ%x OP%x,%u}",
34 op->object->debug_id, op->debug_id, atomic_read(&op->usage));
35
David Howells5753c442009-11-19 18:11:19 +000036 ASSERT(list_empty(&op->pend_link));
David Howells952efe72009-04-03 16:42:39 +010037 ASSERT(op->processor != NULL);
David Howells493f7bc2013-05-10 19:50:26 +010038 ASSERT(fscache_object_is_available(op->object));
David Howells952efe72009-04-03 16:42:39 +010039 ASSERTCMP(atomic_read(&op->usage), >, 0);
David Howells9f105232012-12-20 21:52:35 +000040 ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);
David Howells952efe72009-04-03 16:42:39 +010041
David Howells5753c442009-11-19 18:11:19 +000042 fscache_stat(&fscache_n_op_enqueue);
43 switch (op->flags & FSCACHE_OP_TYPE) {
Tejun Heo8af7c122010-07-20 22:09:01 +020044 case FSCACHE_OP_ASYNC:
45 _debug("queue async");
David Howells5753c442009-11-19 18:11:19 +000046 atomic_inc(&op->usage);
Tejun Heo8af7c122010-07-20 22:09:01 +020047 if (!queue_work(fscache_op_wq, &op->work))
David Howells5753c442009-11-19 18:11:19 +000048 fscache_put_operation(op);
49 break;
David Howells5753c442009-11-19 18:11:19 +000050 case FSCACHE_OP_MYTHREAD:
51 _debug("queue for caller's attention");
52 break;
53 default:
54 printk(KERN_ERR "FS-Cache: Unexpected op type %lx",
55 op->flags);
56 BUG();
57 break;
David Howells952efe72009-04-03 16:42:39 +010058 }
59}
60EXPORT_SYMBOL(fscache_enqueue_operation);
61
62/*
63 * start an op running
64 */
65static void fscache_run_op(struct fscache_object *object,
66 struct fscache_operation *op)
67{
David Howells9f105232012-12-20 21:52:35 +000068 ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);
69
70 op->state = FSCACHE_OP_ST_IN_PROGRESS;
David Howells952efe72009-04-03 16:42:39 +010071 object->n_in_progress++;
72 if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
73 wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
74 if (op->processor)
75 fscache_enqueue_operation(op);
76 fscache_stat(&fscache_n_op_run);
77}
78
79/*
80 * submit an exclusive operation for an object
81 * - other ops are excluded from running simultaneously with this one
82 * - this gets any extra refs it needs on an op
83 */
84int fscache_submit_exclusive_op(struct fscache_object *object,
85 struct fscache_operation *op)
86{
David Howells8d763492012-12-05 13:34:48 +000087 int ret;
88
David Howells952efe72009-04-03 16:42:39 +010089 _enter("{OBJ%x OP%x},", object->debug_id, op->debug_id);
90
David Howells9f105232012-12-20 21:52:35 +000091 ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
92 ASSERTCMP(atomic_read(&op->usage), >, 0);
93
David Howells952efe72009-04-03 16:42:39 +010094 spin_lock(&object->lock);
95 ASSERTCMP(object->n_ops, >=, object->n_in_progress);
96 ASSERTCMP(object->n_ops, >=, object->n_exclusive);
David Howells5753c442009-11-19 18:11:19 +000097 ASSERT(list_empty(&op->pend_link));
David Howells952efe72009-04-03 16:42:39 +010098
David Howells9f105232012-12-20 21:52:35 +000099 op->state = FSCACHE_OP_ST_PENDING;
David Howells952efe72009-04-03 16:42:39 +0100100 if (fscache_object_is_active(object)) {
101 op->object = object;
102 object->n_ops++;
103 object->n_exclusive++; /* reads and writes must wait */
104
David Howells9f105232012-12-20 21:52:35 +0000105 if (object->n_in_progress > 0) {
David Howells952efe72009-04-03 16:42:39 +0100106 atomic_inc(&op->usage);
107 list_add_tail(&op->pend_link, &object->pending_ops);
108 fscache_stat(&fscache_n_op_pend);
109 } else if (!list_empty(&object->pending_ops)) {
110 atomic_inc(&op->usage);
111 list_add_tail(&op->pend_link, &object->pending_ops);
112 fscache_stat(&fscache_n_op_pend);
113 fscache_start_operations(object);
114 } else {
115 ASSERTCMP(object->n_in_progress, ==, 0);
116 fscache_run_op(object, op);
117 }
118
119 /* need to issue a new write op after this */
120 clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
David Howells8d763492012-12-05 13:34:48 +0000121 ret = 0;
David Howellscaaef692013-05-10 19:50:26 +0100122 } else if (test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
David Howells952efe72009-04-03 16:42:39 +0100123 op->object = object;
124 object->n_ops++;
125 object->n_exclusive++; /* reads and writes must wait */
126 atomic_inc(&op->usage);
127 list_add_tail(&op->pend_link, &object->pending_ops);
128 fscache_stat(&fscache_n_op_pend);
David Howells8d763492012-12-05 13:34:48 +0000129 ret = 0;
David Howells952efe72009-04-03 16:42:39 +0100130 } else {
David Howells8d763492012-12-05 13:34:48 +0000131 /* If we're in any other state, there must have been an I/O
132 * error of some nature.
133 */
134 ASSERT(test_bit(FSCACHE_IOERROR, &object->cache->flags));
135 ret = -EIO;
David Howells952efe72009-04-03 16:42:39 +0100136 }
137
138 spin_unlock(&object->lock);
David Howells8d763492012-12-05 13:34:48 +0000139 return ret;
David Howells952efe72009-04-03 16:42:39 +0100140}
141
142/*
143 * report an unexpected submission
144 */
145static void fscache_report_unexpected_submission(struct fscache_object *object,
146 struct fscache_operation *op,
David Howellscaaef692013-05-10 19:50:26 +0100147 const struct fscache_state *ostate)
David Howells952efe72009-04-03 16:42:39 +0100148{
149 static bool once_only;
150 struct fscache_operation *p;
151 unsigned n;
152
153 if (once_only)
154 return;
155 once_only = true;
156
157 kdebug("unexpected submission OP%x [OBJ%x %s]",
David Howellscaaef692013-05-10 19:50:26 +0100158 op->debug_id, object->debug_id, object->state->name);
159 kdebug("objstate=%s [%s]", object->state->name, ostate->name);
David Howells952efe72009-04-03 16:42:39 +0100160 kdebug("objflags=%lx", object->flags);
161 kdebug("objevent=%lx [%lx]", object->events, object->event_mask);
162 kdebug("ops=%u inp=%u exc=%u",
163 object->n_ops, object->n_in_progress, object->n_exclusive);
164
165 if (!list_empty(&object->pending_ops)) {
166 n = 0;
167 list_for_each_entry(p, &object->pending_ops, pend_link) {
168 ASSERTCMP(p->object, ==, object);
169 kdebug("%p %p", op->processor, op->release);
170 n++;
171 }
172
173 kdebug("n=%u", n);
174 }
175
176 dump_stack();
177}
178
179/*
180 * submit an operation for an object
181 * - objects may be submitted only in the following states:
182 * - during object creation (write ops may be submitted)
183 * - whilst the object is active
184 * - after an I/O error incurred in one of the two above states (op rejected)
185 * - this gets any extra refs it needs on an op
186 */
187int fscache_submit_op(struct fscache_object *object,
188 struct fscache_operation *op)
189{
David Howellscaaef692013-05-10 19:50:26 +0100190 const struct fscache_state *ostate;
David Howells952efe72009-04-03 16:42:39 +0100191 int ret;
192
193 _enter("{OBJ%x OP%x},{%u}",
194 object->debug_id, op->debug_id, atomic_read(&op->usage));
195
David Howells9f105232012-12-20 21:52:35 +0000196 ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
David Howells952efe72009-04-03 16:42:39 +0100197 ASSERTCMP(atomic_read(&op->usage), >, 0);
198
199 spin_lock(&object->lock);
200 ASSERTCMP(object->n_ops, >=, object->n_in_progress);
201 ASSERTCMP(object->n_ops, >=, object->n_exclusive);
David Howells5753c442009-11-19 18:11:19 +0000202 ASSERT(list_empty(&op->pend_link));
David Howells952efe72009-04-03 16:42:39 +0100203
204 ostate = object->state;
205 smp_rmb();
206
David Howells9f105232012-12-20 21:52:35 +0000207 op->state = FSCACHE_OP_ST_PENDING;
David Howells952efe72009-04-03 16:42:39 +0100208 if (fscache_object_is_active(object)) {
209 op->object = object;
210 object->n_ops++;
211
212 if (object->n_exclusive > 0) {
213 atomic_inc(&op->usage);
214 list_add_tail(&op->pend_link, &object->pending_ops);
215 fscache_stat(&fscache_n_op_pend);
216 } else if (!list_empty(&object->pending_ops)) {
217 atomic_inc(&op->usage);
218 list_add_tail(&op->pend_link, &object->pending_ops);
219 fscache_stat(&fscache_n_op_pend);
220 fscache_start_operations(object);
221 } else {
222 ASSERTCMP(object->n_exclusive, ==, 0);
223 fscache_run_op(object, op);
224 }
225 ret = 0;
David Howellscaaef692013-05-10 19:50:26 +0100226 } else if (test_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
David Howells952efe72009-04-03 16:42:39 +0100227 op->object = object;
228 object->n_ops++;
229 atomic_inc(&op->usage);
230 list_add_tail(&op->pend_link, &object->pending_ops);
231 fscache_stat(&fscache_n_op_pend);
232 ret = 0;
David Howellscaaef692013-05-10 19:50:26 +0100233 } else if (fscache_object_is_dying(object)) {
David Howellse3d4d282009-11-19 18:11:32 +0000234 fscache_stat(&fscache_n_op_rejected);
David Howells9f105232012-12-20 21:52:35 +0000235 op->state = FSCACHE_OP_ST_CANCELLED;
David Howellse3d4d282009-11-19 18:11:32 +0000236 ret = -ENOBUFS;
David Howells952efe72009-04-03 16:42:39 +0100237 } else if (!test_bit(FSCACHE_IOERROR, &object->cache->flags)) {
238 fscache_report_unexpected_submission(object, op, ostate);
239 ASSERT(!fscache_object_is_active(object));
David Howells9f105232012-12-20 21:52:35 +0000240 op->state = FSCACHE_OP_ST_CANCELLED;
David Howells952efe72009-04-03 16:42:39 +0100241 ret = -ENOBUFS;
242 } else {
David Howells9f105232012-12-20 21:52:35 +0000243 op->state = FSCACHE_OP_ST_CANCELLED;
David Howells952efe72009-04-03 16:42:39 +0100244 ret = -ENOBUFS;
245 }
246
247 spin_unlock(&object->lock);
248 return ret;
249}
250
251/*
252 * queue an object for withdrawal on error, aborting all following asynchronous
253 * operations
254 */
255void fscache_abort_object(struct fscache_object *object)
256{
257 _enter("{OBJ%x}", object->debug_id);
258
259 fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
260}
261
262/*
263 * jump start the operation processing on an object
David Howells952efe72009-04-03 16:42:39 +0100264 */
265void fscache_start_operations(struct fscache_object *object)
266{
267 struct fscache_operation *op;
268 bool stop = false;
269
David Howellscaaef692013-05-10 19:50:26 +0100270 ASSERT(spin_is_locked(&object->lock));
271
David Howells952efe72009-04-03 16:42:39 +0100272 while (!list_empty(&object->pending_ops) && !stop) {
273 op = list_entry(object->pending_ops.next,
274 struct fscache_operation, pend_link);
275
276 if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) {
277 if (object->n_in_progress > 0)
278 break;
279 stop = true;
280 }
281 list_del_init(&op->pend_link);
David Howells5753c442009-11-19 18:11:19 +0000282 fscache_run_op(object, op);
David Howells952efe72009-04-03 16:42:39 +0100283
284 /* the pending queue was holding a ref on the object */
285 fscache_put_operation(op);
286 }
287
288 ASSERTCMP(object->n_in_progress, <=, object->n_ops);
289
290 _debug("woke %d ops on OBJ%x",
291 object->n_in_progress, object->debug_id);
292}
293
294/*
David Howells5753c442009-11-19 18:11:19 +0000295 * cancel an operation that's pending on an object
296 */
David Howells91c7fbb2012-12-14 11:02:22 +0000297int fscache_cancel_op(struct fscache_operation *op,
298 void (*do_cancel)(struct fscache_operation *))
David Howells5753c442009-11-19 18:11:19 +0000299{
300 struct fscache_object *object = op->object;
301 int ret;
302
303 _enter("OBJ%x OP%x}", op->object->debug_id, op->debug_id);
304
David Howells9f105232012-12-20 21:52:35 +0000305 ASSERTCMP(op->state, >=, FSCACHE_OP_ST_PENDING);
306 ASSERTCMP(op->state, !=, FSCACHE_OP_ST_CANCELLED);
307 ASSERTCMP(atomic_read(&op->usage), >, 0);
308
David Howells5753c442009-11-19 18:11:19 +0000309 spin_lock(&object->lock);
310
311 ret = -EBUSY;
David Howells9f105232012-12-20 21:52:35 +0000312 if (op->state == FSCACHE_OP_ST_PENDING) {
313 ASSERT(!list_empty(&op->pend_link));
David Howells5753c442009-11-19 18:11:19 +0000314 fscache_stat(&fscache_n_op_cancelled);
315 list_del_init(&op->pend_link);
David Howells91c7fbb2012-12-14 11:02:22 +0000316 if (do_cancel)
317 do_cancel(op);
David Howells9f105232012-12-20 21:52:35 +0000318 op->state = FSCACHE_OP_ST_CANCELLED;
David Howells5753c442009-11-19 18:11:19 +0000319 if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
320 object->n_exclusive--;
321 if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
322 wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
323 fscache_put_operation(op);
324 ret = 0;
325 }
326
327 spin_unlock(&object->lock);
328 _leave(" = %d", ret);
329 return ret;
330}
331
332/*
David Howellsef778e72012-12-20 21:52:36 +0000333 * Cancel all pending operations on an object
334 */
335void fscache_cancel_all_ops(struct fscache_object *object)
336{
337 struct fscache_operation *op;
338
339 _enter("OBJ%x", object->debug_id);
340
341 spin_lock(&object->lock);
342
343 while (!list_empty(&object->pending_ops)) {
344 op = list_entry(object->pending_ops.next,
345 struct fscache_operation, pend_link);
346 fscache_stat(&fscache_n_op_cancelled);
347 list_del_init(&op->pend_link);
348
349 ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);
350 op->state = FSCACHE_OP_ST_CANCELLED;
351
352 if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
353 object->n_exclusive--;
354 if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
355 wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
356 fscache_put_operation(op);
357 cond_resched_lock(&object->lock);
358 }
359
360 spin_unlock(&object->lock);
361 _leave("");
362}
363
364/*
David Howells1f372df2012-12-13 20:03:13 +0000365 * Record the completion or cancellation of an in-progress operation.
David Howells9f105232012-12-20 21:52:35 +0000366 */
David Howells1f372df2012-12-13 20:03:13 +0000367void fscache_op_complete(struct fscache_operation *op, bool cancelled)
David Howells9f105232012-12-20 21:52:35 +0000368{
369 struct fscache_object *object = op->object;
370
371 _enter("OBJ%x", object->debug_id);
372
373 ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);
374 ASSERTCMP(object->n_in_progress, >, 0);
375 ASSERTIFCMP(test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags),
376 object->n_exclusive, >, 0);
377 ASSERTIFCMP(test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags),
378 object->n_in_progress, ==, 1);
379
380 spin_lock(&object->lock);
381
David Howells1f372df2012-12-13 20:03:13 +0000382 op->state = cancelled ?
383 FSCACHE_OP_ST_CANCELLED : FSCACHE_OP_ST_COMPLETE;
David Howells9f105232012-12-20 21:52:35 +0000384
385 if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
386 object->n_exclusive--;
387 object->n_in_progress--;
388 if (object->n_in_progress == 0)
389 fscache_start_operations(object);
390
391 spin_unlock(&object->lock);
392 _leave("");
393}
394EXPORT_SYMBOL(fscache_op_complete);
395
396/*
David Howells952efe72009-04-03 16:42:39 +0100397 * release an operation
398 * - queues pending ops if this is the last in-progress op
399 */
400void fscache_put_operation(struct fscache_operation *op)
401{
402 struct fscache_object *object;
403 struct fscache_cache *cache;
404
405 _enter("{OBJ%x OP%x,%d}",
406 op->object->debug_id, op->debug_id, atomic_read(&op->usage));
407
408 ASSERTCMP(atomic_read(&op->usage), >, 0);
409
410 if (!atomic_dec_and_test(&op->usage))
411 return;
412
413 _debug("PUT OP");
David Howells9f105232012-12-20 21:52:35 +0000414 ASSERTIFCMP(op->state != FSCACHE_OP_ST_COMPLETE,
415 op->state, ==, FSCACHE_OP_ST_CANCELLED);
416 op->state = FSCACHE_OP_ST_DEAD;
David Howells952efe72009-04-03 16:42:39 +0100417
418 fscache_stat(&fscache_n_op_release);
419
420 if (op->release) {
421 op->release(op);
422 op->release = NULL;
423 }
424
425 object = op->object;
426
David Howells13627292013-05-10 19:50:26 +0100427 if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags))
428 atomic_dec(&object->n_reads);
429 if (test_bit(FSCACHE_OP_UNUSE_COOKIE, &op->flags))
430 fscache_unuse_cookie(object);
David Howells4fbf4292009-11-19 18:11:04 +0000431
David Howells952efe72009-04-03 16:42:39 +0100432 /* now... we may get called with the object spinlock held, so we
433 * complete the cleanup here only if we can immediately acquire the
434 * lock, and defer it otherwise */
435 if (!spin_trylock(&object->lock)) {
436 _debug("defer put");
437 fscache_stat(&fscache_n_op_deferred_release);
438
439 cache = object->cache;
440 spin_lock(&cache->op_gc_list_lock);
441 list_add_tail(&op->pend_link, &cache->op_gc_list);
442 spin_unlock(&cache->op_gc_list_lock);
443 schedule_work(&cache->op_gc);
444 _leave(" [defer]");
445 return;
446 }
447
David Howells952efe72009-04-03 16:42:39 +0100448 ASSERTCMP(object->n_ops, >, 0);
449 object->n_ops--;
450 if (object->n_ops == 0)
451 fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);
452
453 spin_unlock(&object->lock);
454
455 kfree(op);
456 _leave(" [done]");
457}
458EXPORT_SYMBOL(fscache_put_operation);
459
460/*
461 * garbage collect operations that have had their release deferred
462 */
463void fscache_operation_gc(struct work_struct *work)
464{
465 struct fscache_operation *op;
466 struct fscache_object *object;
467 struct fscache_cache *cache =
468 container_of(work, struct fscache_cache, op_gc);
469 int count = 0;
470
471 _enter("");
472
473 do {
474 spin_lock(&cache->op_gc_list_lock);
475 if (list_empty(&cache->op_gc_list)) {
476 spin_unlock(&cache->op_gc_list_lock);
477 break;
478 }
479
480 op = list_entry(cache->op_gc_list.next,
481 struct fscache_operation, pend_link);
482 list_del(&op->pend_link);
483 spin_unlock(&cache->op_gc_list_lock);
484
485 object = op->object;
David Howells9f105232012-12-20 21:52:35 +0000486 spin_lock(&object->lock);
David Howells952efe72009-04-03 16:42:39 +0100487
488 _debug("GC DEFERRED REL OBJ%x OP%x",
489 object->debug_id, op->debug_id);
490 fscache_stat(&fscache_n_op_gc);
491
492 ASSERTCMP(atomic_read(&op->usage), ==, 0);
David Howells9f105232012-12-20 21:52:35 +0000493 ASSERTCMP(op->state, ==, FSCACHE_OP_ST_DEAD);
David Howells952efe72009-04-03 16:42:39 +0100494
495 ASSERTCMP(object->n_ops, >, 0);
496 object->n_ops--;
497 if (object->n_ops == 0)
498 fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);
499
500 spin_unlock(&object->lock);
David Howells9f105232012-12-20 21:52:35 +0000501 kfree(op);
David Howells952efe72009-04-03 16:42:39 +0100502
503 } while (count++ < 20);
504
505 if (!list_empty(&cache->op_gc_list))
506 schedule_work(&cache->op_gc);
507
508 _leave("");
509}
510
511/*
Tejun Heo8af7c122010-07-20 22:09:01 +0200512 * execute an operation using fs_op_wq to provide processing context -
513 * the caller holds a ref to this object, so we don't need to hold one
David Howells952efe72009-04-03 16:42:39 +0100514 */
Tejun Heo8af7c122010-07-20 22:09:01 +0200515void fscache_op_work_func(struct work_struct *work)
David Howells952efe72009-04-03 16:42:39 +0100516{
517 struct fscache_operation *op =
Tejun Heo8af7c122010-07-20 22:09:01 +0200518 container_of(work, struct fscache_operation, work);
David Howells952efe72009-04-03 16:42:39 +0100519 unsigned long start;
520
521 _enter("{OBJ%x OP%x,%d}",
522 op->object->debug_id, op->debug_id, atomic_read(&op->usage));
523
524 ASSERT(op->processor != NULL);
525 start = jiffies;
526 op->processor(op);
527 fscache_hist(fscache_ops_histogram, start);
Tejun Heo8af7c122010-07-20 22:09:01 +0200528 fscache_put_operation(op);
David Howells952efe72009-04-03 16:42:39 +0100529
530 _leave("");
531}