xref: /linux/drivers/md/bcache/sysfs.c (revision 9a379e77033f02c4a071891afdf0f0a01eff8ccb)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * bcache sysfs interfaces
4  *
5  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
6  * Copyright 2012 Google, Inc.
7  */
8 
9 #include "bcache.h"
10 #include "sysfs.h"
11 #include "btree.h"
12 #include "request.h"
13 #include "writeback.h"
14 
15 #include <linux/blkdev.h>
16 #include <linux/sort.h>
17 #include <linux/sched/clock.h>
18 
19 static const char * const cache_replacement_policies[] = {
20 	"lru",
21 	"fifo",
22 	"random",
23 	NULL
24 };
25 
26 static const char * const error_actions[] = {
27 	"unregister",
28 	"panic",
29 	NULL
30 };
31 
32 write_attribute(attach);
33 write_attribute(detach);
34 write_attribute(unregister);
35 write_attribute(stop);
36 write_attribute(clear_stats);
37 write_attribute(trigger_gc);
38 write_attribute(prune_cache);
39 write_attribute(flash_vol_create);
40 
41 read_attribute(bucket_size);
42 read_attribute(block_size);
43 read_attribute(nbuckets);
44 read_attribute(tree_depth);
45 read_attribute(root_usage_percent);
46 read_attribute(priority_stats);
47 read_attribute(btree_cache_size);
48 read_attribute(btree_cache_max_chain);
49 read_attribute(cache_available_percent);
50 read_attribute(written);
51 read_attribute(btree_written);
52 read_attribute(metadata_written);
53 read_attribute(active_journal_entries);
54 
55 sysfs_time_stats_attribute(btree_gc,	sec, ms);
56 sysfs_time_stats_attribute(btree_split, sec, us);
57 sysfs_time_stats_attribute(btree_sort,	ms,  us);
58 sysfs_time_stats_attribute(btree_read,	ms,  us);
59 
60 read_attribute(btree_nodes);
61 read_attribute(btree_used_percent);
62 read_attribute(average_key_size);
63 read_attribute(dirty_data);
64 read_attribute(bset_tree_stats);
65 
66 read_attribute(state);
67 read_attribute(cache_read_races);
68 read_attribute(reclaim);
69 read_attribute(flush_write);
70 read_attribute(retry_flush_write);
71 read_attribute(writeback_keys_done);
72 read_attribute(writeback_keys_failed);
73 read_attribute(io_errors);
74 read_attribute(congested);
75 rw_attribute(congested_read_threshold_us);
76 rw_attribute(congested_write_threshold_us);
77 
78 rw_attribute(sequential_cutoff);
79 rw_attribute(data_csum);
80 rw_attribute(cache_mode);
81 rw_attribute(writeback_metadata);
82 rw_attribute(writeback_running);
83 rw_attribute(writeback_percent);
84 rw_attribute(writeback_delay);
85 rw_attribute(writeback_rate);
86 
87 rw_attribute(writeback_rate_update_seconds);
88 rw_attribute(writeback_rate_i_term_inverse);
89 rw_attribute(writeback_rate_p_term_inverse);
90 rw_attribute(writeback_rate_minimum);
91 read_attribute(writeback_rate_debug);
92 
93 read_attribute(stripe_size);
94 read_attribute(partial_stripes_expensive);
95 
96 rw_attribute(synchronous);
97 rw_attribute(journal_delay_ms);
98 rw_attribute(discard);
99 rw_attribute(running);
100 rw_attribute(label);
101 rw_attribute(readahead);
102 rw_attribute(errors);
103 rw_attribute(io_error_limit);
104 rw_attribute(io_error_halflife);
105 rw_attribute(verify);
106 rw_attribute(bypass_torture_test);
107 rw_attribute(key_merging_disabled);
108 rw_attribute(gc_always_rewrite);
109 rw_attribute(expensive_debug_checks);
110 rw_attribute(cache_replacement_policy);
111 rw_attribute(btree_shrinker_disabled);
112 rw_attribute(copy_gc_enabled);
113 rw_attribute(size);
114 
115 SHOW(__bch_cached_dev)
116 {
117 	struct cached_dev *dc = container_of(kobj, struct cached_dev,
118 					     disk.kobj);
119 	const char *states[] = { "no cache", "clean", "dirty", "inconsistent" };
120 
121 #define var(stat)		(dc->stat)
122 
123 	if (attr == &sysfs_cache_mode)
124 		return bch_snprint_string_list(buf, PAGE_SIZE,
125 					       bch_cache_modes + 1,
126 					       BDEV_CACHE_MODE(&dc->sb));
127 
128 	sysfs_printf(data_csum,		"%i", dc->disk.data_csum);
129 	var_printf(verify,		"%i");
130 	var_printf(bypass_torture_test,	"%i");
131 	var_printf(writeback_metadata,	"%i");
132 	var_printf(writeback_running,	"%i");
133 	var_print(writeback_delay);
134 	var_print(writeback_percent);
135 	sysfs_hprint(writeback_rate,	dc->writeback_rate.rate << 9);
136 
137 	var_print(writeback_rate_update_seconds);
138 	var_print(writeback_rate_i_term_inverse);
139 	var_print(writeback_rate_p_term_inverse);
140 	var_print(writeback_rate_minimum);
141 
142 	if (attr == &sysfs_writeback_rate_debug) {
143 		char rate[20];
144 		char dirty[20];
145 		char target[20];
146 		char proportional[20];
147 		char integral[20];
148 		char change[20];
149 		s64 next_io;
150 
151 		bch_hprint(rate,	dc->writeback_rate.rate << 9);
152 		bch_hprint(dirty,	bcache_dev_sectors_dirty(&dc->disk) << 9);
153 		bch_hprint(target,	dc->writeback_rate_target << 9);
154 		bch_hprint(proportional,dc->writeback_rate_proportional << 9);
155 		bch_hprint(integral,	dc->writeback_rate_integral_scaled << 9);
156 		bch_hprint(change,	dc->writeback_rate_change << 9);
157 
158 		next_io = div64_s64(dc->writeback_rate.next - local_clock(),
159 				    NSEC_PER_MSEC);
160 
161 		return sprintf(buf,
162 			       "rate:\t\t%s/sec\n"
163 			       "dirty:\t\t%s\n"
164 			       "target:\t\t%s\n"
165 			       "proportional:\t%s\n"
166 			       "integral:\t%s\n"
167 			       "change:\t\t%s/sec\n"
168 			       "next io:\t%llims\n",
169 			       rate, dirty, target, proportional,
170 			       integral, change, next_io);
171 	}
172 
173 	sysfs_hprint(dirty_data,
174 		     bcache_dev_sectors_dirty(&dc->disk) << 9);
175 
176 	sysfs_hprint(stripe_size,	dc->disk.stripe_size << 9);
177 	var_printf(partial_stripes_expensive,	"%u");
178 
179 	var_hprint(sequential_cutoff);
180 	var_hprint(readahead);
181 
182 	sysfs_print(running,		atomic_read(&dc->running));
183 	sysfs_print(state,		states[BDEV_STATE(&dc->sb)]);
184 
185 	if (attr == &sysfs_label) {
186 		memcpy(buf, dc->sb.label, SB_LABEL_SIZE);
187 		buf[SB_LABEL_SIZE + 1] = '\0';
188 		strcat(buf, "\n");
189 		return strlen(buf);
190 	}
191 
192 #undef var
193 	return 0;
194 }
195 SHOW_LOCKED(bch_cached_dev)
196 
197 STORE(__cached_dev)
198 {
199 	struct cached_dev *dc = container_of(kobj, struct cached_dev,
200 					     disk.kobj);
201 	ssize_t v;
202 	struct cache_set *c;
203 	struct kobj_uevent_env *env;
204 
205 #define d_strtoul(var)		sysfs_strtoul(var, dc->var)
206 #define d_strtoul_nonzero(var)	sysfs_strtoul_clamp(var, dc->var, 1, INT_MAX)
207 #define d_strtoi_h(var)		sysfs_hatoi(var, dc->var)
208 
209 	sysfs_strtoul(data_csum,	dc->disk.data_csum);
210 	d_strtoul(verify);
211 	d_strtoul(bypass_torture_test);
212 	d_strtoul(writeback_metadata);
213 	d_strtoul(writeback_running);
214 	d_strtoul(writeback_delay);
215 
216 	sysfs_strtoul_clamp(writeback_percent, dc->writeback_percent, 0, 40);
217 
218 	sysfs_strtoul_clamp(writeback_rate,
219 			    dc->writeback_rate.rate, 1, INT_MAX);
220 
221 	sysfs_strtoul_clamp(writeback_rate_update_seconds,
222 			    dc->writeback_rate_update_seconds,
223 			    1, WRITEBACK_RATE_UPDATE_SECS_MAX);
224 	d_strtoul(writeback_rate_i_term_inverse);
225 	d_strtoul_nonzero(writeback_rate_p_term_inverse);
226 
227 	d_strtoi_h(sequential_cutoff);
228 	d_strtoi_h(readahead);
229 
230 	if (attr == &sysfs_clear_stats)
231 		bch_cache_accounting_clear(&dc->accounting);
232 
233 	if (attr == &sysfs_running &&
234 	    strtoul_or_return(buf))
235 		bch_cached_dev_run(dc);
236 
237 	if (attr == &sysfs_cache_mode) {
238 		v = bch_read_string_list(buf, bch_cache_modes + 1);
239 
240 		if (v < 0)
241 			return v;
242 
243 		if ((unsigned) v != BDEV_CACHE_MODE(&dc->sb)) {
244 			SET_BDEV_CACHE_MODE(&dc->sb, v);
245 			bch_write_bdev_super(dc, NULL);
246 		}
247 	}
248 
249 	if (attr == &sysfs_label) {
250 		if (size > SB_LABEL_SIZE)
251 			return -EINVAL;
252 		memcpy(dc->sb.label, buf, size);
253 		if (size < SB_LABEL_SIZE)
254 			dc->sb.label[size] = '\0';
255 		if (size && dc->sb.label[size - 1] == '\n')
256 			dc->sb.label[size - 1] = '\0';
257 		bch_write_bdev_super(dc, NULL);
258 		if (dc->disk.c) {
259 			memcpy(dc->disk.c->uuids[dc->disk.id].label,
260 			       buf, SB_LABEL_SIZE);
261 			bch_uuid_write(dc->disk.c);
262 		}
263 		env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
264 		if (!env)
265 			return -ENOMEM;
266 		add_uevent_var(env, "DRIVER=bcache");
267 		add_uevent_var(env, "CACHED_UUID=%pU", dc->sb.uuid),
268 		add_uevent_var(env, "CACHED_LABEL=%s", buf);
269 		kobject_uevent_env(
270 			&disk_to_dev(dc->disk.disk)->kobj, KOBJ_CHANGE, env->envp);
271 		kfree(env);
272 	}
273 
274 	if (attr == &sysfs_attach) {
275 		uint8_t		set_uuid[16];
276 
277 		if (bch_parse_uuid(buf, set_uuid) < 16)
278 			return -EINVAL;
279 
280 		v = -ENOENT;
281 		list_for_each_entry(c, &bch_cache_sets, list) {
282 			v = bch_cached_dev_attach(dc, c, set_uuid);
283 			if (!v)
284 				return size;
285 		}
286 
287 		pr_err("Can't attach %s: cache set not found", buf);
288 		return v;
289 	}
290 
291 	if (attr == &sysfs_detach && dc->disk.c)
292 		bch_cached_dev_detach(dc);
293 
294 	if (attr == &sysfs_stop)
295 		bcache_device_stop(&dc->disk);
296 
297 	return size;
298 }
299 
300 STORE(bch_cached_dev)
301 {
302 	struct cached_dev *dc = container_of(kobj, struct cached_dev,
303 					     disk.kobj);
304 
305 	mutex_lock(&bch_register_lock);
306 	size = __cached_dev_store(kobj, attr, buf, size);
307 
308 	if (attr == &sysfs_writeback_running)
309 		bch_writeback_queue(dc);
310 
311 	if (attr == &sysfs_writeback_percent)
312 		schedule_delayed_work(&dc->writeback_rate_update,
313 				      dc->writeback_rate_update_seconds * HZ);
314 
315 	mutex_unlock(&bch_register_lock);
316 	return size;
317 }
318 
319 static struct attribute *bch_cached_dev_files[] = {
320 	&sysfs_attach,
321 	&sysfs_detach,
322 	&sysfs_stop,
323 #if 0
324 	&sysfs_data_csum,
325 #endif
326 	&sysfs_cache_mode,
327 	&sysfs_writeback_metadata,
328 	&sysfs_writeback_running,
329 	&sysfs_writeback_delay,
330 	&sysfs_writeback_percent,
331 	&sysfs_writeback_rate,
332 	&sysfs_writeback_rate_update_seconds,
333 	&sysfs_writeback_rate_i_term_inverse,
334 	&sysfs_writeback_rate_p_term_inverse,
335 	&sysfs_writeback_rate_debug,
336 	&sysfs_dirty_data,
337 	&sysfs_stripe_size,
338 	&sysfs_partial_stripes_expensive,
339 	&sysfs_sequential_cutoff,
340 	&sysfs_clear_stats,
341 	&sysfs_running,
342 	&sysfs_state,
343 	&sysfs_label,
344 	&sysfs_readahead,
345 #ifdef CONFIG_BCACHE_DEBUG
346 	&sysfs_verify,
347 	&sysfs_bypass_torture_test,
348 #endif
349 	NULL
350 };
351 KTYPE(bch_cached_dev);
352 
353 SHOW(bch_flash_dev)
354 {
355 	struct bcache_device *d = container_of(kobj, struct bcache_device,
356 					       kobj);
357 	struct uuid_entry *u = &d->c->uuids[d->id];
358 
359 	sysfs_printf(data_csum,	"%i", d->data_csum);
360 	sysfs_hprint(size,	u->sectors << 9);
361 
362 	if (attr == &sysfs_label) {
363 		memcpy(buf, u->label, SB_LABEL_SIZE);
364 		buf[SB_LABEL_SIZE + 1] = '\0';
365 		strcat(buf, "\n");
366 		return strlen(buf);
367 	}
368 
369 	return 0;
370 }
371 
372 STORE(__bch_flash_dev)
373 {
374 	struct bcache_device *d = container_of(kobj, struct bcache_device,
375 					       kobj);
376 	struct uuid_entry *u = &d->c->uuids[d->id];
377 
378 	sysfs_strtoul(data_csum,	d->data_csum);
379 
380 	if (attr == &sysfs_size) {
381 		uint64_t v;
382 		strtoi_h_or_return(buf, v);
383 
384 		u->sectors = v >> 9;
385 		bch_uuid_write(d->c);
386 		set_capacity(d->disk, u->sectors);
387 	}
388 
389 	if (attr == &sysfs_label) {
390 		memcpy(u->label, buf, SB_LABEL_SIZE);
391 		bch_uuid_write(d->c);
392 	}
393 
394 	if (attr == &sysfs_unregister) {
395 		set_bit(BCACHE_DEV_DETACHING, &d->flags);
396 		bcache_device_stop(d);
397 	}
398 
399 	return size;
400 }
401 STORE_LOCKED(bch_flash_dev)
402 
403 static struct attribute *bch_flash_dev_files[] = {
404 	&sysfs_unregister,
405 #if 0
406 	&sysfs_data_csum,
407 #endif
408 	&sysfs_label,
409 	&sysfs_size,
410 	NULL
411 };
412 KTYPE(bch_flash_dev);
413 
414 struct bset_stats_op {
415 	struct btree_op op;
416 	size_t nodes;
417 	struct bset_stats stats;
418 };
419 
420 static int bch_btree_bset_stats(struct btree_op *b_op, struct btree *b)
421 {
422 	struct bset_stats_op *op = container_of(b_op, struct bset_stats_op, op);
423 
424 	op->nodes++;
425 	bch_btree_keys_stats(&b->keys, &op->stats);
426 
427 	return MAP_CONTINUE;
428 }
429 
430 static int bch_bset_print_stats(struct cache_set *c, char *buf)
431 {
432 	struct bset_stats_op op;
433 	int ret;
434 
435 	memset(&op, 0, sizeof(op));
436 	bch_btree_op_init(&op.op, -1);
437 
438 	ret = bch_btree_map_nodes(&op.op, c, &ZERO_KEY, bch_btree_bset_stats);
439 	if (ret < 0)
440 		return ret;
441 
442 	return snprintf(buf, PAGE_SIZE,
443 			"btree nodes:		%zu\n"
444 			"written sets:		%zu\n"
445 			"unwritten sets:		%zu\n"
446 			"written key bytes:	%zu\n"
447 			"unwritten key bytes:	%zu\n"
448 			"floats:			%zu\n"
449 			"failed:			%zu\n",
450 			op.nodes,
451 			op.stats.sets_written, op.stats.sets_unwritten,
452 			op.stats.bytes_written, op.stats.bytes_unwritten,
453 			op.stats.floats, op.stats.failed);
454 }
455 
456 static unsigned bch_root_usage(struct cache_set *c)
457 {
458 	unsigned bytes = 0;
459 	struct bkey *k;
460 	struct btree *b;
461 	struct btree_iter iter;
462 
463 	goto lock_root;
464 
465 	do {
466 		rw_unlock(false, b);
467 lock_root:
468 		b = c->root;
469 		rw_lock(false, b, b->level);
470 	} while (b != c->root);
471 
472 	for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
473 		bytes += bkey_bytes(k);
474 
475 	rw_unlock(false, b);
476 
477 	return (bytes * 100) / btree_bytes(c);
478 }
479 
480 static size_t bch_cache_size(struct cache_set *c)
481 {
482 	size_t ret = 0;
483 	struct btree *b;
484 
485 	mutex_lock(&c->bucket_lock);
486 	list_for_each_entry(b, &c->btree_cache, list)
487 		ret += 1 << (b->keys.page_order + PAGE_SHIFT);
488 
489 	mutex_unlock(&c->bucket_lock);
490 	return ret;
491 }
492 
493 static unsigned bch_cache_max_chain(struct cache_set *c)
494 {
495 	unsigned ret = 0;
496 	struct hlist_head *h;
497 
498 	mutex_lock(&c->bucket_lock);
499 
500 	for (h = c->bucket_hash;
501 	     h < c->bucket_hash + (1 << BUCKET_HASH_BITS);
502 	     h++) {
503 		unsigned i = 0;
504 		struct hlist_node *p;
505 
506 		hlist_for_each(p, h)
507 			i++;
508 
509 		ret = max(ret, i);
510 	}
511 
512 	mutex_unlock(&c->bucket_lock);
513 	return ret;
514 }
515 
516 static unsigned bch_btree_used(struct cache_set *c)
517 {
518 	return div64_u64(c->gc_stats.key_bytes * 100,
519 			 (c->gc_stats.nodes ?: 1) * btree_bytes(c));
520 }
521 
522 static unsigned bch_average_key_size(struct cache_set *c)
523 {
524 	return c->gc_stats.nkeys
525 		? div64_u64(c->gc_stats.data, c->gc_stats.nkeys)
526 		: 0;
527 }
528 
529 SHOW(__bch_cache_set)
530 {
531 	struct cache_set *c = container_of(kobj, struct cache_set, kobj);
532 
533 	sysfs_print(synchronous,		CACHE_SYNC(&c->sb));
534 	sysfs_print(journal_delay_ms,		c->journal_delay_ms);
535 	sysfs_hprint(bucket_size,		bucket_bytes(c));
536 	sysfs_hprint(block_size,		block_bytes(c));
537 	sysfs_print(tree_depth,			c->root->level);
538 	sysfs_print(root_usage_percent,		bch_root_usage(c));
539 
540 	sysfs_hprint(btree_cache_size,		bch_cache_size(c));
541 	sysfs_print(btree_cache_max_chain,	bch_cache_max_chain(c));
542 	sysfs_print(cache_available_percent,	100 - c->gc_stats.in_use);
543 
544 	sysfs_print_time_stats(&c->btree_gc_time,	btree_gc, sec, ms);
545 	sysfs_print_time_stats(&c->btree_split_time,	btree_split, sec, us);
546 	sysfs_print_time_stats(&c->sort.time,		btree_sort, ms, us);
547 	sysfs_print_time_stats(&c->btree_read_time,	btree_read, ms, us);
548 
549 	sysfs_print(btree_used_percent,	bch_btree_used(c));
550 	sysfs_print(btree_nodes,	c->gc_stats.nodes);
551 	sysfs_hprint(average_key_size,	bch_average_key_size(c));
552 
553 	sysfs_print(cache_read_races,
554 		    atomic_long_read(&c->cache_read_races));
555 
556 	sysfs_print(reclaim,
557 		    atomic_long_read(&c->reclaim));
558 
559 	sysfs_print(flush_write,
560 		    atomic_long_read(&c->flush_write));
561 
562 	sysfs_print(retry_flush_write,
563 		    atomic_long_read(&c->retry_flush_write));
564 
565 	sysfs_print(writeback_keys_done,
566 		    atomic_long_read(&c->writeback_keys_done));
567 	sysfs_print(writeback_keys_failed,
568 		    atomic_long_read(&c->writeback_keys_failed));
569 
570 	if (attr == &sysfs_errors)
571 		return bch_snprint_string_list(buf, PAGE_SIZE, error_actions,
572 					       c->on_error);
573 
574 	/* See count_io_errors for why 88 */
575 	sysfs_print(io_error_halflife,	c->error_decay * 88);
576 	sysfs_print(io_error_limit,	c->error_limit);
577 
578 	sysfs_hprint(congested,
579 		     ((uint64_t) bch_get_congested(c)) << 9);
580 	sysfs_print(congested_read_threshold_us,
581 		    c->congested_read_threshold_us);
582 	sysfs_print(congested_write_threshold_us,
583 		    c->congested_write_threshold_us);
584 
585 	sysfs_print(active_journal_entries,	fifo_used(&c->journal.pin));
586 	sysfs_printf(verify,			"%i", c->verify);
587 	sysfs_printf(key_merging_disabled,	"%i", c->key_merging_disabled);
588 	sysfs_printf(expensive_debug_checks,
589 		     "%i", c->expensive_debug_checks);
590 	sysfs_printf(gc_always_rewrite,		"%i", c->gc_always_rewrite);
591 	sysfs_printf(btree_shrinker_disabled,	"%i", c->shrinker_disabled);
592 	sysfs_printf(copy_gc_enabled,		"%i", c->copy_gc_enabled);
593 
594 	if (attr == &sysfs_bset_tree_stats)
595 		return bch_bset_print_stats(c, buf);
596 
597 	return 0;
598 }
599 SHOW_LOCKED(bch_cache_set)
600 
601 STORE(__bch_cache_set)
602 {
603 	struct cache_set *c = container_of(kobj, struct cache_set, kobj);
604 
605 	if (attr == &sysfs_unregister)
606 		bch_cache_set_unregister(c);
607 
608 	if (attr == &sysfs_stop)
609 		bch_cache_set_stop(c);
610 
611 	if (attr == &sysfs_synchronous) {
612 		bool sync = strtoul_or_return(buf);
613 
614 		if (sync != CACHE_SYNC(&c->sb)) {
615 			SET_CACHE_SYNC(&c->sb, sync);
616 			bcache_write_super(c);
617 		}
618 	}
619 
620 	if (attr == &sysfs_flash_vol_create) {
621 		int r;
622 		uint64_t v;
623 		strtoi_h_or_return(buf, v);
624 
625 		r = bch_flash_dev_create(c, v);
626 		if (r)
627 			return r;
628 	}
629 
630 	if (attr == &sysfs_clear_stats) {
631 		atomic_long_set(&c->writeback_keys_done,	0);
632 		atomic_long_set(&c->writeback_keys_failed,	0);
633 
634 		memset(&c->gc_stats, 0, sizeof(struct gc_stat));
635 		bch_cache_accounting_clear(&c->accounting);
636 	}
637 
638 	if (attr == &sysfs_trigger_gc) {
639 		/*
640 		 * Garbage collection thread only works when sectors_to_gc < 0,
641 		 * when users write to sysfs entry trigger_gc, most of time
642 		 * they want to forcibly triger gargage collection. Here -1 is
643 		 * set to c->sectors_to_gc, to make gc_should_run() give a
644 		 * chance to permit gc thread to run. "give a chance" means
645 		 * before going into gc_should_run(), there is still chance
646 		 * that c->sectors_to_gc being set to other positive value. So
647 		 * writing sysfs entry trigger_gc won't always make sure gc
648 		 * thread takes effect.
649 		 */
650 		atomic_set(&c->sectors_to_gc, -1);
651 		wake_up_gc(c);
652 	}
653 
654 	if (attr == &sysfs_prune_cache) {
655 		struct shrink_control sc;
656 		sc.gfp_mask = GFP_KERNEL;
657 		sc.nr_to_scan = strtoul_or_return(buf);
658 		c->shrink.scan_objects(&c->shrink, &sc);
659 	}
660 
661 	sysfs_strtoul(congested_read_threshold_us,
662 		      c->congested_read_threshold_us);
663 	sysfs_strtoul(congested_write_threshold_us,
664 		      c->congested_write_threshold_us);
665 
666 	if (attr == &sysfs_errors) {
667 		ssize_t v = bch_read_string_list(buf, error_actions);
668 
669 		if (v < 0)
670 			return v;
671 
672 		c->on_error = v;
673 	}
674 
675 	if (attr == &sysfs_io_error_limit)
676 		c->error_limit = strtoul_or_return(buf);
677 
678 	/* See count_io_errors() for why 88 */
679 	if (attr == &sysfs_io_error_halflife)
680 		c->error_decay = strtoul_or_return(buf) / 88;
681 
682 	sysfs_strtoul(journal_delay_ms,		c->journal_delay_ms);
683 	sysfs_strtoul(verify,			c->verify);
684 	sysfs_strtoul(key_merging_disabled,	c->key_merging_disabled);
685 	sysfs_strtoul(expensive_debug_checks,	c->expensive_debug_checks);
686 	sysfs_strtoul(gc_always_rewrite,	c->gc_always_rewrite);
687 	sysfs_strtoul(btree_shrinker_disabled,	c->shrinker_disabled);
688 	sysfs_strtoul(copy_gc_enabled,		c->copy_gc_enabled);
689 
690 	return size;
691 }
692 STORE_LOCKED(bch_cache_set)
693 
694 SHOW(bch_cache_set_internal)
695 {
696 	struct cache_set *c = container_of(kobj, struct cache_set, internal);
697 	return bch_cache_set_show(&c->kobj, attr, buf);
698 }
699 
700 STORE(bch_cache_set_internal)
701 {
702 	struct cache_set *c = container_of(kobj, struct cache_set, internal);
703 	return bch_cache_set_store(&c->kobj, attr, buf, size);
704 }
705 
706 static void bch_cache_set_internal_release(struct kobject *k)
707 {
708 }
709 
710 static struct attribute *bch_cache_set_files[] = {
711 	&sysfs_unregister,
712 	&sysfs_stop,
713 	&sysfs_synchronous,
714 	&sysfs_journal_delay_ms,
715 	&sysfs_flash_vol_create,
716 
717 	&sysfs_bucket_size,
718 	&sysfs_block_size,
719 	&sysfs_tree_depth,
720 	&sysfs_root_usage_percent,
721 	&sysfs_btree_cache_size,
722 	&sysfs_cache_available_percent,
723 
724 	&sysfs_average_key_size,
725 
726 	&sysfs_errors,
727 	&sysfs_io_error_limit,
728 	&sysfs_io_error_halflife,
729 	&sysfs_congested,
730 	&sysfs_congested_read_threshold_us,
731 	&sysfs_congested_write_threshold_us,
732 	&sysfs_clear_stats,
733 	NULL
734 };
735 KTYPE(bch_cache_set);
736 
737 static struct attribute *bch_cache_set_internal_files[] = {
738 	&sysfs_active_journal_entries,
739 
740 	sysfs_time_stats_attribute_list(btree_gc, sec, ms)
741 	sysfs_time_stats_attribute_list(btree_split, sec, us)
742 	sysfs_time_stats_attribute_list(btree_sort, ms, us)
743 	sysfs_time_stats_attribute_list(btree_read, ms, us)
744 
745 	&sysfs_btree_nodes,
746 	&sysfs_btree_used_percent,
747 	&sysfs_btree_cache_max_chain,
748 
749 	&sysfs_bset_tree_stats,
750 	&sysfs_cache_read_races,
751 	&sysfs_reclaim,
752 	&sysfs_flush_write,
753 	&sysfs_retry_flush_write,
754 	&sysfs_writeback_keys_done,
755 	&sysfs_writeback_keys_failed,
756 
757 	&sysfs_trigger_gc,
758 	&sysfs_prune_cache,
759 #ifdef CONFIG_BCACHE_DEBUG
760 	&sysfs_verify,
761 	&sysfs_key_merging_disabled,
762 	&sysfs_expensive_debug_checks,
763 #endif
764 	&sysfs_gc_always_rewrite,
765 	&sysfs_btree_shrinker_disabled,
766 	&sysfs_copy_gc_enabled,
767 	NULL
768 };
769 KTYPE(bch_cache_set_internal);
770 
771 static int __bch_cache_cmp(const void *l, const void *r)
772 {
773 	return *((uint16_t *)r) - *((uint16_t *)l);
774 }
775 
776 SHOW(__bch_cache)
777 {
778 	struct cache *ca = container_of(kobj, struct cache, kobj);
779 
780 	sysfs_hprint(bucket_size,	bucket_bytes(ca));
781 	sysfs_hprint(block_size,	block_bytes(ca));
782 	sysfs_print(nbuckets,		ca->sb.nbuckets);
783 	sysfs_print(discard,		ca->discard);
784 	sysfs_hprint(written, atomic_long_read(&ca->sectors_written) << 9);
785 	sysfs_hprint(btree_written,
786 		     atomic_long_read(&ca->btree_sectors_written) << 9);
787 	sysfs_hprint(metadata_written,
788 		     (atomic_long_read(&ca->meta_sectors_written) +
789 		      atomic_long_read(&ca->btree_sectors_written)) << 9);
790 
791 	sysfs_print(io_errors,
792 		    atomic_read(&ca->io_errors) >> IO_ERROR_SHIFT);
793 
794 	if (attr == &sysfs_cache_replacement_policy)
795 		return bch_snprint_string_list(buf, PAGE_SIZE,
796 					       cache_replacement_policies,
797 					       CACHE_REPLACEMENT(&ca->sb));
798 
799 	if (attr == &sysfs_priority_stats) {
800 		struct bucket *b;
801 		size_t n = ca->sb.nbuckets, i;
802 		size_t unused = 0, available = 0, dirty = 0, meta = 0;
803 		uint64_t sum = 0;
804 		/* Compute 31 quantiles */
805 		uint16_t q[31], *p, *cached;
806 		ssize_t ret;
807 
808 		cached = p = vmalloc(ca->sb.nbuckets * sizeof(uint16_t));
809 		if (!p)
810 			return -ENOMEM;
811 
812 		mutex_lock(&ca->set->bucket_lock);
813 		for_each_bucket(b, ca) {
814 			if (!GC_SECTORS_USED(b))
815 				unused++;
816 			if (GC_MARK(b) == GC_MARK_RECLAIMABLE)
817 				available++;
818 			if (GC_MARK(b) == GC_MARK_DIRTY)
819 				dirty++;
820 			if (GC_MARK(b) == GC_MARK_METADATA)
821 				meta++;
822 		}
823 
824 		for (i = ca->sb.first_bucket; i < n; i++)
825 			p[i] = ca->buckets[i].prio;
826 		mutex_unlock(&ca->set->bucket_lock);
827 
828 		sort(p, n, sizeof(uint16_t), __bch_cache_cmp, NULL);
829 
830 		while (n &&
831 		       !cached[n - 1])
832 			--n;
833 
834 		unused = ca->sb.nbuckets - n;
835 
836 		while (cached < p + n &&
837 		       *cached == BTREE_PRIO)
838 			cached++, n--;
839 
840 		for (i = 0; i < n; i++)
841 			sum += INITIAL_PRIO - cached[i];
842 
843 		if (n)
844 			do_div(sum, n);
845 
846 		for (i = 0; i < ARRAY_SIZE(q); i++)
847 			q[i] = INITIAL_PRIO - cached[n * (i + 1) /
848 				(ARRAY_SIZE(q) + 1)];
849 
850 		vfree(p);
851 
852 		ret = scnprintf(buf, PAGE_SIZE,
853 				"Unused:		%zu%%\n"
854 				"Clean:		%zu%%\n"
855 				"Dirty:		%zu%%\n"
856 				"Metadata:	%zu%%\n"
857 				"Average:	%llu\n"
858 				"Sectors per Q:	%zu\n"
859 				"Quantiles:	[",
860 				unused * 100 / (size_t) ca->sb.nbuckets,
861 				available * 100 / (size_t) ca->sb.nbuckets,
862 				dirty * 100 / (size_t) ca->sb.nbuckets,
863 				meta * 100 / (size_t) ca->sb.nbuckets, sum,
864 				n * ca->sb.bucket_size / (ARRAY_SIZE(q) + 1));
865 
866 		for (i = 0; i < ARRAY_SIZE(q); i++)
867 			ret += scnprintf(buf + ret, PAGE_SIZE - ret,
868 					 "%u ", q[i]);
869 		ret--;
870 
871 		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "]\n");
872 
873 		return ret;
874 	}
875 
876 	return 0;
877 }
878 SHOW_LOCKED(bch_cache)
879 
880 STORE(__bch_cache)
881 {
882 	struct cache *ca = container_of(kobj, struct cache, kobj);
883 
884 	if (attr == &sysfs_discard) {
885 		bool v = strtoul_or_return(buf);
886 
887 		if (blk_queue_discard(bdev_get_queue(ca->bdev)))
888 			ca->discard = v;
889 
890 		if (v != CACHE_DISCARD(&ca->sb)) {
891 			SET_CACHE_DISCARD(&ca->sb, v);
892 			bcache_write_super(ca->set);
893 		}
894 	}
895 
896 	if (attr == &sysfs_cache_replacement_policy) {
897 		ssize_t v = bch_read_string_list(buf, cache_replacement_policies);
898 
899 		if (v < 0)
900 			return v;
901 
902 		if ((unsigned) v != CACHE_REPLACEMENT(&ca->sb)) {
903 			mutex_lock(&ca->set->bucket_lock);
904 			SET_CACHE_REPLACEMENT(&ca->sb, v);
905 			mutex_unlock(&ca->set->bucket_lock);
906 
907 			bcache_write_super(ca->set);
908 		}
909 	}
910 
911 	if (attr == &sysfs_clear_stats) {
912 		atomic_long_set(&ca->sectors_written, 0);
913 		atomic_long_set(&ca->btree_sectors_written, 0);
914 		atomic_long_set(&ca->meta_sectors_written, 0);
915 		atomic_set(&ca->io_count, 0);
916 		atomic_set(&ca->io_errors, 0);
917 	}
918 
919 	return size;
920 }
921 STORE_LOCKED(bch_cache)
922 
923 static struct attribute *bch_cache_files[] = {
924 	&sysfs_bucket_size,
925 	&sysfs_block_size,
926 	&sysfs_nbuckets,
927 	&sysfs_priority_stats,
928 	&sysfs_discard,
929 	&sysfs_written,
930 	&sysfs_btree_written,
931 	&sysfs_metadata_written,
932 	&sysfs_io_errors,
933 	&sysfs_clear_stats,
934 	&sysfs_cache_replacement_policy,
935 	NULL
936 };
937 KTYPE(bch_cache);
938