xref: /openbmc/linux/drivers/md/bcache/sysfs.c (revision bf070bb0)
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(writeback_keys_done);
69 read_attribute(writeback_keys_failed);
70 read_attribute(io_errors);
71 read_attribute(congested);
72 rw_attribute(congested_read_threshold_us);
73 rw_attribute(congested_write_threshold_us);
74 
75 rw_attribute(sequential_cutoff);
76 rw_attribute(data_csum);
77 rw_attribute(cache_mode);
78 rw_attribute(writeback_metadata);
79 rw_attribute(writeback_running);
80 rw_attribute(writeback_percent);
81 rw_attribute(writeback_delay);
82 rw_attribute(writeback_rate);
83 
84 rw_attribute(writeback_rate_update_seconds);
85 rw_attribute(writeback_rate_i_term_inverse);
86 rw_attribute(writeback_rate_p_term_inverse);
87 rw_attribute(writeback_rate_minimum);
88 read_attribute(writeback_rate_debug);
89 
90 read_attribute(stripe_size);
91 read_attribute(partial_stripes_expensive);
92 
93 rw_attribute(synchronous);
94 rw_attribute(journal_delay_ms);
95 rw_attribute(discard);
96 rw_attribute(running);
97 rw_attribute(label);
98 rw_attribute(readahead);
99 rw_attribute(errors);
100 rw_attribute(io_error_limit);
101 rw_attribute(io_error_halflife);
102 rw_attribute(verify);
103 rw_attribute(bypass_torture_test);
104 rw_attribute(key_merging_disabled);
105 rw_attribute(gc_always_rewrite);
106 rw_attribute(expensive_debug_checks);
107 rw_attribute(cache_replacement_policy);
108 rw_attribute(btree_shrinker_disabled);
109 rw_attribute(copy_gc_enabled);
110 rw_attribute(size);
111 
112 SHOW(__bch_cached_dev)
113 {
114 	struct cached_dev *dc = container_of(kobj, struct cached_dev,
115 					     disk.kobj);
116 	const char *states[] = { "no cache", "clean", "dirty", "inconsistent" };
117 
118 #define var(stat)		(dc->stat)
119 
120 	if (attr == &sysfs_cache_mode)
121 		return bch_snprint_string_list(buf, PAGE_SIZE,
122 					       bch_cache_modes + 1,
123 					       BDEV_CACHE_MODE(&dc->sb));
124 
125 	sysfs_printf(data_csum,		"%i", dc->disk.data_csum);
126 	var_printf(verify,		"%i");
127 	var_printf(bypass_torture_test,	"%i");
128 	var_printf(writeback_metadata,	"%i");
129 	var_printf(writeback_running,	"%i");
130 	var_print(writeback_delay);
131 	var_print(writeback_percent);
132 	sysfs_hprint(writeback_rate,	dc->writeback_rate.rate << 9);
133 
134 	var_print(writeback_rate_update_seconds);
135 	var_print(writeback_rate_i_term_inverse);
136 	var_print(writeback_rate_p_term_inverse);
137 	var_print(writeback_rate_minimum);
138 
139 	if (attr == &sysfs_writeback_rate_debug) {
140 		char rate[20];
141 		char dirty[20];
142 		char target[20];
143 		char proportional[20];
144 		char integral[20];
145 		char change[20];
146 		s64 next_io;
147 
148 		bch_hprint(rate,	dc->writeback_rate.rate << 9);
149 		bch_hprint(dirty,	bcache_dev_sectors_dirty(&dc->disk) << 9);
150 		bch_hprint(target,	dc->writeback_rate_target << 9);
151 		bch_hprint(proportional,dc->writeback_rate_proportional << 9);
152 		bch_hprint(integral,	dc->writeback_rate_integral_scaled << 9);
153 		bch_hprint(change,	dc->writeback_rate_change << 9);
154 
155 		next_io = div64_s64(dc->writeback_rate.next - local_clock(),
156 				    NSEC_PER_MSEC);
157 
158 		return sprintf(buf,
159 			       "rate:\t\t%s/sec\n"
160 			       "dirty:\t\t%s\n"
161 			       "target:\t\t%s\n"
162 			       "proportional:\t%s\n"
163 			       "integral:\t%s\n"
164 			       "change:\t\t%s/sec\n"
165 			       "next io:\t%llims\n",
166 			       rate, dirty, target, proportional,
167 			       integral, change, next_io);
168 	}
169 
170 	sysfs_hprint(dirty_data,
171 		     bcache_dev_sectors_dirty(&dc->disk) << 9);
172 
173 	sysfs_hprint(stripe_size,	dc->disk.stripe_size << 9);
174 	var_printf(partial_stripes_expensive,	"%u");
175 
176 	var_hprint(sequential_cutoff);
177 	var_hprint(readahead);
178 
179 	sysfs_print(running,		atomic_read(&dc->running));
180 	sysfs_print(state,		states[BDEV_STATE(&dc->sb)]);
181 
182 	if (attr == &sysfs_label) {
183 		memcpy(buf, dc->sb.label, SB_LABEL_SIZE);
184 		buf[SB_LABEL_SIZE + 1] = '\0';
185 		strcat(buf, "\n");
186 		return strlen(buf);
187 	}
188 
189 #undef var
190 	return 0;
191 }
192 SHOW_LOCKED(bch_cached_dev)
193 
194 STORE(__cached_dev)
195 {
196 	struct cached_dev *dc = container_of(kobj, struct cached_dev,
197 					     disk.kobj);
198 	ssize_t v = size;
199 	struct cache_set *c;
200 	struct kobj_uevent_env *env;
201 
202 #define d_strtoul(var)		sysfs_strtoul(var, dc->var)
203 #define d_strtoul_nonzero(var)	sysfs_strtoul_clamp(var, dc->var, 1, INT_MAX)
204 #define d_strtoi_h(var)		sysfs_hatoi(var, dc->var)
205 
206 	sysfs_strtoul(data_csum,	dc->disk.data_csum);
207 	d_strtoul(verify);
208 	d_strtoul(bypass_torture_test);
209 	d_strtoul(writeback_metadata);
210 	d_strtoul(writeback_running);
211 	d_strtoul(writeback_delay);
212 
213 	sysfs_strtoul_clamp(writeback_percent, dc->writeback_percent, 0, 40);
214 
215 	sysfs_strtoul_clamp(writeback_rate,
216 			    dc->writeback_rate.rate, 1, INT_MAX);
217 
218 	d_strtoul_nonzero(writeback_rate_update_seconds);
219 	d_strtoul(writeback_rate_i_term_inverse);
220 	d_strtoul_nonzero(writeback_rate_p_term_inverse);
221 
222 	d_strtoi_h(sequential_cutoff);
223 	d_strtoi_h(readahead);
224 
225 	if (attr == &sysfs_clear_stats)
226 		bch_cache_accounting_clear(&dc->accounting);
227 
228 	if (attr == &sysfs_running &&
229 	    strtoul_or_return(buf))
230 		bch_cached_dev_run(dc);
231 
232 	if (attr == &sysfs_cache_mode) {
233 		v = bch_read_string_list(buf, bch_cache_modes + 1);
234 
235 		if (v < 0)
236 			return v;
237 
238 		if ((unsigned) v != BDEV_CACHE_MODE(&dc->sb)) {
239 			SET_BDEV_CACHE_MODE(&dc->sb, v);
240 			bch_write_bdev_super(dc, NULL);
241 		}
242 	}
243 
244 	if (attr == &sysfs_label) {
245 		if (size > SB_LABEL_SIZE)
246 			return -EINVAL;
247 		memcpy(dc->sb.label, buf, size);
248 		if (size < SB_LABEL_SIZE)
249 			dc->sb.label[size] = '\0';
250 		if (size && dc->sb.label[size - 1] == '\n')
251 			dc->sb.label[size - 1] = '\0';
252 		bch_write_bdev_super(dc, NULL);
253 		if (dc->disk.c) {
254 			memcpy(dc->disk.c->uuids[dc->disk.id].label,
255 			       buf, SB_LABEL_SIZE);
256 			bch_uuid_write(dc->disk.c);
257 		}
258 		env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
259 		if (!env)
260 			return -ENOMEM;
261 		add_uevent_var(env, "DRIVER=bcache");
262 		add_uevent_var(env, "CACHED_UUID=%pU", dc->sb.uuid),
263 		add_uevent_var(env, "CACHED_LABEL=%s", buf);
264 		kobject_uevent_env(
265 			&disk_to_dev(dc->disk.disk)->kobj, KOBJ_CHANGE, env->envp);
266 		kfree(env);
267 	}
268 
269 	if (attr == &sysfs_attach) {
270 		if (bch_parse_uuid(buf, dc->sb.set_uuid) < 16)
271 			return -EINVAL;
272 
273 		list_for_each_entry(c, &bch_cache_sets, list) {
274 			v = bch_cached_dev_attach(dc, c);
275 			if (!v)
276 				return size;
277 		}
278 
279 		pr_err("Can't attach %s: cache set not found", buf);
280 		size = v;
281 	}
282 
283 	if (attr == &sysfs_detach && dc->disk.c)
284 		bch_cached_dev_detach(dc);
285 
286 	if (attr == &sysfs_stop)
287 		bcache_device_stop(&dc->disk);
288 
289 	return size;
290 }
291 
292 STORE(bch_cached_dev)
293 {
294 	struct cached_dev *dc = container_of(kobj, struct cached_dev,
295 					     disk.kobj);
296 
297 	mutex_lock(&bch_register_lock);
298 	size = __cached_dev_store(kobj, attr, buf, size);
299 
300 	if (attr == &sysfs_writeback_running)
301 		bch_writeback_queue(dc);
302 
303 	if (attr == &sysfs_writeback_percent)
304 		schedule_delayed_work(&dc->writeback_rate_update,
305 				      dc->writeback_rate_update_seconds * HZ);
306 
307 	mutex_unlock(&bch_register_lock);
308 	return size;
309 }
310 
311 static struct attribute *bch_cached_dev_files[] = {
312 	&sysfs_attach,
313 	&sysfs_detach,
314 	&sysfs_stop,
315 #if 0
316 	&sysfs_data_csum,
317 #endif
318 	&sysfs_cache_mode,
319 	&sysfs_writeback_metadata,
320 	&sysfs_writeback_running,
321 	&sysfs_writeback_delay,
322 	&sysfs_writeback_percent,
323 	&sysfs_writeback_rate,
324 	&sysfs_writeback_rate_update_seconds,
325 	&sysfs_writeback_rate_i_term_inverse,
326 	&sysfs_writeback_rate_p_term_inverse,
327 	&sysfs_writeback_rate_debug,
328 	&sysfs_dirty_data,
329 	&sysfs_stripe_size,
330 	&sysfs_partial_stripes_expensive,
331 	&sysfs_sequential_cutoff,
332 	&sysfs_clear_stats,
333 	&sysfs_running,
334 	&sysfs_state,
335 	&sysfs_label,
336 	&sysfs_readahead,
337 #ifdef CONFIG_BCACHE_DEBUG
338 	&sysfs_verify,
339 	&sysfs_bypass_torture_test,
340 #endif
341 	NULL
342 };
343 KTYPE(bch_cached_dev);
344 
345 SHOW(bch_flash_dev)
346 {
347 	struct bcache_device *d = container_of(kobj, struct bcache_device,
348 					       kobj);
349 	struct uuid_entry *u = &d->c->uuids[d->id];
350 
351 	sysfs_printf(data_csum,	"%i", d->data_csum);
352 	sysfs_hprint(size,	u->sectors << 9);
353 
354 	if (attr == &sysfs_label) {
355 		memcpy(buf, u->label, SB_LABEL_SIZE);
356 		buf[SB_LABEL_SIZE + 1] = '\0';
357 		strcat(buf, "\n");
358 		return strlen(buf);
359 	}
360 
361 	return 0;
362 }
363 
364 STORE(__bch_flash_dev)
365 {
366 	struct bcache_device *d = container_of(kobj, struct bcache_device,
367 					       kobj);
368 	struct uuid_entry *u = &d->c->uuids[d->id];
369 
370 	sysfs_strtoul(data_csum,	d->data_csum);
371 
372 	if (attr == &sysfs_size) {
373 		uint64_t v;
374 		strtoi_h_or_return(buf, v);
375 
376 		u->sectors = v >> 9;
377 		bch_uuid_write(d->c);
378 		set_capacity(d->disk, u->sectors);
379 	}
380 
381 	if (attr == &sysfs_label) {
382 		memcpy(u->label, buf, SB_LABEL_SIZE);
383 		bch_uuid_write(d->c);
384 	}
385 
386 	if (attr == &sysfs_unregister) {
387 		set_bit(BCACHE_DEV_DETACHING, &d->flags);
388 		bcache_device_stop(d);
389 	}
390 
391 	return size;
392 }
393 STORE_LOCKED(bch_flash_dev)
394 
395 static struct attribute *bch_flash_dev_files[] = {
396 	&sysfs_unregister,
397 #if 0
398 	&sysfs_data_csum,
399 #endif
400 	&sysfs_label,
401 	&sysfs_size,
402 	NULL
403 };
404 KTYPE(bch_flash_dev);
405 
406 struct bset_stats_op {
407 	struct btree_op op;
408 	size_t nodes;
409 	struct bset_stats stats;
410 };
411 
412 static int bch_btree_bset_stats(struct btree_op *b_op, struct btree *b)
413 {
414 	struct bset_stats_op *op = container_of(b_op, struct bset_stats_op, op);
415 
416 	op->nodes++;
417 	bch_btree_keys_stats(&b->keys, &op->stats);
418 
419 	return MAP_CONTINUE;
420 }
421 
422 static int bch_bset_print_stats(struct cache_set *c, char *buf)
423 {
424 	struct bset_stats_op op;
425 	int ret;
426 
427 	memset(&op, 0, sizeof(op));
428 	bch_btree_op_init(&op.op, -1);
429 
430 	ret = bch_btree_map_nodes(&op.op, c, &ZERO_KEY, bch_btree_bset_stats);
431 	if (ret < 0)
432 		return ret;
433 
434 	return snprintf(buf, PAGE_SIZE,
435 			"btree nodes:		%zu\n"
436 			"written sets:		%zu\n"
437 			"unwritten sets:		%zu\n"
438 			"written key bytes:	%zu\n"
439 			"unwritten key bytes:	%zu\n"
440 			"floats:			%zu\n"
441 			"failed:			%zu\n",
442 			op.nodes,
443 			op.stats.sets_written, op.stats.sets_unwritten,
444 			op.stats.bytes_written, op.stats.bytes_unwritten,
445 			op.stats.floats, op.stats.failed);
446 }
447 
448 static unsigned bch_root_usage(struct cache_set *c)
449 {
450 	unsigned bytes = 0;
451 	struct bkey *k;
452 	struct btree *b;
453 	struct btree_iter iter;
454 
455 	goto lock_root;
456 
457 	do {
458 		rw_unlock(false, b);
459 lock_root:
460 		b = c->root;
461 		rw_lock(false, b, b->level);
462 	} while (b != c->root);
463 
464 	for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
465 		bytes += bkey_bytes(k);
466 
467 	rw_unlock(false, b);
468 
469 	return (bytes * 100) / btree_bytes(c);
470 }
471 
472 static size_t bch_cache_size(struct cache_set *c)
473 {
474 	size_t ret = 0;
475 	struct btree *b;
476 
477 	mutex_lock(&c->bucket_lock);
478 	list_for_each_entry(b, &c->btree_cache, list)
479 		ret += 1 << (b->keys.page_order + PAGE_SHIFT);
480 
481 	mutex_unlock(&c->bucket_lock);
482 	return ret;
483 }
484 
485 static unsigned bch_cache_max_chain(struct cache_set *c)
486 {
487 	unsigned ret = 0;
488 	struct hlist_head *h;
489 
490 	mutex_lock(&c->bucket_lock);
491 
492 	for (h = c->bucket_hash;
493 	     h < c->bucket_hash + (1 << BUCKET_HASH_BITS);
494 	     h++) {
495 		unsigned i = 0;
496 		struct hlist_node *p;
497 
498 		hlist_for_each(p, h)
499 			i++;
500 
501 		ret = max(ret, i);
502 	}
503 
504 	mutex_unlock(&c->bucket_lock);
505 	return ret;
506 }
507 
508 static unsigned bch_btree_used(struct cache_set *c)
509 {
510 	return div64_u64(c->gc_stats.key_bytes * 100,
511 			 (c->gc_stats.nodes ?: 1) * btree_bytes(c));
512 }
513 
514 static unsigned bch_average_key_size(struct cache_set *c)
515 {
516 	return c->gc_stats.nkeys
517 		? div64_u64(c->gc_stats.data, c->gc_stats.nkeys)
518 		: 0;
519 }
520 
521 SHOW(__bch_cache_set)
522 {
523 	struct cache_set *c = container_of(kobj, struct cache_set, kobj);
524 
525 	sysfs_print(synchronous,		CACHE_SYNC(&c->sb));
526 	sysfs_print(journal_delay_ms,		c->journal_delay_ms);
527 	sysfs_hprint(bucket_size,		bucket_bytes(c));
528 	sysfs_hprint(block_size,		block_bytes(c));
529 	sysfs_print(tree_depth,			c->root->level);
530 	sysfs_print(root_usage_percent,		bch_root_usage(c));
531 
532 	sysfs_hprint(btree_cache_size,		bch_cache_size(c));
533 	sysfs_print(btree_cache_max_chain,	bch_cache_max_chain(c));
534 	sysfs_print(cache_available_percent,	100 - c->gc_stats.in_use);
535 
536 	sysfs_print_time_stats(&c->btree_gc_time,	btree_gc, sec, ms);
537 	sysfs_print_time_stats(&c->btree_split_time,	btree_split, sec, us);
538 	sysfs_print_time_stats(&c->sort.time,		btree_sort, ms, us);
539 	sysfs_print_time_stats(&c->btree_read_time,	btree_read, ms, us);
540 
541 	sysfs_print(btree_used_percent,	bch_btree_used(c));
542 	sysfs_print(btree_nodes,	c->gc_stats.nodes);
543 	sysfs_hprint(average_key_size,	bch_average_key_size(c));
544 
545 	sysfs_print(cache_read_races,
546 		    atomic_long_read(&c->cache_read_races));
547 
548 	sysfs_print(writeback_keys_done,
549 		    atomic_long_read(&c->writeback_keys_done));
550 	sysfs_print(writeback_keys_failed,
551 		    atomic_long_read(&c->writeback_keys_failed));
552 
553 	if (attr == &sysfs_errors)
554 		return bch_snprint_string_list(buf, PAGE_SIZE, error_actions,
555 					       c->on_error);
556 
557 	/* See count_io_errors for why 88 */
558 	sysfs_print(io_error_halflife,	c->error_decay * 88);
559 	sysfs_print(io_error_limit,	c->error_limit >> IO_ERROR_SHIFT);
560 
561 	sysfs_hprint(congested,
562 		     ((uint64_t) bch_get_congested(c)) << 9);
563 	sysfs_print(congested_read_threshold_us,
564 		    c->congested_read_threshold_us);
565 	sysfs_print(congested_write_threshold_us,
566 		    c->congested_write_threshold_us);
567 
568 	sysfs_print(active_journal_entries,	fifo_used(&c->journal.pin));
569 	sysfs_printf(verify,			"%i", c->verify);
570 	sysfs_printf(key_merging_disabled,	"%i", c->key_merging_disabled);
571 	sysfs_printf(expensive_debug_checks,
572 		     "%i", c->expensive_debug_checks);
573 	sysfs_printf(gc_always_rewrite,		"%i", c->gc_always_rewrite);
574 	sysfs_printf(btree_shrinker_disabled,	"%i", c->shrinker_disabled);
575 	sysfs_printf(copy_gc_enabled,		"%i", c->copy_gc_enabled);
576 
577 	if (attr == &sysfs_bset_tree_stats)
578 		return bch_bset_print_stats(c, buf);
579 
580 	return 0;
581 }
582 SHOW_LOCKED(bch_cache_set)
583 
584 STORE(__bch_cache_set)
585 {
586 	struct cache_set *c = container_of(kobj, struct cache_set, kobj);
587 
588 	if (attr == &sysfs_unregister)
589 		bch_cache_set_unregister(c);
590 
591 	if (attr == &sysfs_stop)
592 		bch_cache_set_stop(c);
593 
594 	if (attr == &sysfs_synchronous) {
595 		bool sync = strtoul_or_return(buf);
596 
597 		if (sync != CACHE_SYNC(&c->sb)) {
598 			SET_CACHE_SYNC(&c->sb, sync);
599 			bcache_write_super(c);
600 		}
601 	}
602 
603 	if (attr == &sysfs_flash_vol_create) {
604 		int r;
605 		uint64_t v;
606 		strtoi_h_or_return(buf, v);
607 
608 		r = bch_flash_dev_create(c, v);
609 		if (r)
610 			return r;
611 	}
612 
613 	if (attr == &sysfs_clear_stats) {
614 		atomic_long_set(&c->writeback_keys_done,	0);
615 		atomic_long_set(&c->writeback_keys_failed,	0);
616 
617 		memset(&c->gc_stats, 0, sizeof(struct gc_stat));
618 		bch_cache_accounting_clear(&c->accounting);
619 	}
620 
621 	if (attr == &sysfs_trigger_gc) {
622 		/*
623 		 * Garbage collection thread only works when sectors_to_gc < 0,
624 		 * when users write to sysfs entry trigger_gc, most of time
625 		 * they want to forcibly triger gargage collection. Here -1 is
626 		 * set to c->sectors_to_gc, to make gc_should_run() give a
627 		 * chance to permit gc thread to run. "give a chance" means
628 		 * before going into gc_should_run(), there is still chance
629 		 * that c->sectors_to_gc being set to other positive value. So
630 		 * writing sysfs entry trigger_gc won't always make sure gc
631 		 * thread takes effect.
632 		 */
633 		atomic_set(&c->sectors_to_gc, -1);
634 		wake_up_gc(c);
635 	}
636 
637 	if (attr == &sysfs_prune_cache) {
638 		struct shrink_control sc;
639 		sc.gfp_mask = GFP_KERNEL;
640 		sc.nr_to_scan = strtoul_or_return(buf);
641 		c->shrink.scan_objects(&c->shrink, &sc);
642 	}
643 
644 	sysfs_strtoul(congested_read_threshold_us,
645 		      c->congested_read_threshold_us);
646 	sysfs_strtoul(congested_write_threshold_us,
647 		      c->congested_write_threshold_us);
648 
649 	if (attr == &sysfs_errors) {
650 		ssize_t v = bch_read_string_list(buf, error_actions);
651 
652 		if (v < 0)
653 			return v;
654 
655 		c->on_error = v;
656 	}
657 
658 	if (attr == &sysfs_io_error_limit)
659 		c->error_limit = strtoul_or_return(buf) << IO_ERROR_SHIFT;
660 
661 	/* See count_io_errors() for why 88 */
662 	if (attr == &sysfs_io_error_halflife)
663 		c->error_decay = strtoul_or_return(buf) / 88;
664 
665 	sysfs_strtoul(journal_delay_ms,		c->journal_delay_ms);
666 	sysfs_strtoul(verify,			c->verify);
667 	sysfs_strtoul(key_merging_disabled,	c->key_merging_disabled);
668 	sysfs_strtoul(expensive_debug_checks,	c->expensive_debug_checks);
669 	sysfs_strtoul(gc_always_rewrite,	c->gc_always_rewrite);
670 	sysfs_strtoul(btree_shrinker_disabled,	c->shrinker_disabled);
671 	sysfs_strtoul(copy_gc_enabled,		c->copy_gc_enabled);
672 
673 	return size;
674 }
675 STORE_LOCKED(bch_cache_set)
676 
677 SHOW(bch_cache_set_internal)
678 {
679 	struct cache_set *c = container_of(kobj, struct cache_set, internal);
680 	return bch_cache_set_show(&c->kobj, attr, buf);
681 }
682 
683 STORE(bch_cache_set_internal)
684 {
685 	struct cache_set *c = container_of(kobj, struct cache_set, internal);
686 	return bch_cache_set_store(&c->kobj, attr, buf, size);
687 }
688 
689 static void bch_cache_set_internal_release(struct kobject *k)
690 {
691 }
692 
693 static struct attribute *bch_cache_set_files[] = {
694 	&sysfs_unregister,
695 	&sysfs_stop,
696 	&sysfs_synchronous,
697 	&sysfs_journal_delay_ms,
698 	&sysfs_flash_vol_create,
699 
700 	&sysfs_bucket_size,
701 	&sysfs_block_size,
702 	&sysfs_tree_depth,
703 	&sysfs_root_usage_percent,
704 	&sysfs_btree_cache_size,
705 	&sysfs_cache_available_percent,
706 
707 	&sysfs_average_key_size,
708 
709 	&sysfs_errors,
710 	&sysfs_io_error_limit,
711 	&sysfs_io_error_halflife,
712 	&sysfs_congested,
713 	&sysfs_congested_read_threshold_us,
714 	&sysfs_congested_write_threshold_us,
715 	&sysfs_clear_stats,
716 	NULL
717 };
718 KTYPE(bch_cache_set);
719 
720 static struct attribute *bch_cache_set_internal_files[] = {
721 	&sysfs_active_journal_entries,
722 
723 	sysfs_time_stats_attribute_list(btree_gc, sec, ms)
724 	sysfs_time_stats_attribute_list(btree_split, sec, us)
725 	sysfs_time_stats_attribute_list(btree_sort, ms, us)
726 	sysfs_time_stats_attribute_list(btree_read, ms, us)
727 
728 	&sysfs_btree_nodes,
729 	&sysfs_btree_used_percent,
730 	&sysfs_btree_cache_max_chain,
731 
732 	&sysfs_bset_tree_stats,
733 	&sysfs_cache_read_races,
734 	&sysfs_writeback_keys_done,
735 	&sysfs_writeback_keys_failed,
736 
737 	&sysfs_trigger_gc,
738 	&sysfs_prune_cache,
739 #ifdef CONFIG_BCACHE_DEBUG
740 	&sysfs_verify,
741 	&sysfs_key_merging_disabled,
742 	&sysfs_expensive_debug_checks,
743 #endif
744 	&sysfs_gc_always_rewrite,
745 	&sysfs_btree_shrinker_disabled,
746 	&sysfs_copy_gc_enabled,
747 	NULL
748 };
749 KTYPE(bch_cache_set_internal);
750 
751 static int __bch_cache_cmp(const void *l, const void *r)
752 {
753 	return *((uint16_t *)r) - *((uint16_t *)l);
754 }
755 
756 SHOW(__bch_cache)
757 {
758 	struct cache *ca = container_of(kobj, struct cache, kobj);
759 
760 	sysfs_hprint(bucket_size,	bucket_bytes(ca));
761 	sysfs_hprint(block_size,	block_bytes(ca));
762 	sysfs_print(nbuckets,		ca->sb.nbuckets);
763 	sysfs_print(discard,		ca->discard);
764 	sysfs_hprint(written, atomic_long_read(&ca->sectors_written) << 9);
765 	sysfs_hprint(btree_written,
766 		     atomic_long_read(&ca->btree_sectors_written) << 9);
767 	sysfs_hprint(metadata_written,
768 		     (atomic_long_read(&ca->meta_sectors_written) +
769 		      atomic_long_read(&ca->btree_sectors_written)) << 9);
770 
771 	sysfs_print(io_errors,
772 		    atomic_read(&ca->io_errors) >> IO_ERROR_SHIFT);
773 
774 	if (attr == &sysfs_cache_replacement_policy)
775 		return bch_snprint_string_list(buf, PAGE_SIZE,
776 					       cache_replacement_policies,
777 					       CACHE_REPLACEMENT(&ca->sb));
778 
779 	if (attr == &sysfs_priority_stats) {
780 		struct bucket *b;
781 		size_t n = ca->sb.nbuckets, i;
782 		size_t unused = 0, available = 0, dirty = 0, meta = 0;
783 		uint64_t sum = 0;
784 		/* Compute 31 quantiles */
785 		uint16_t q[31], *p, *cached;
786 		ssize_t ret;
787 
788 		cached = p = vmalloc(ca->sb.nbuckets * sizeof(uint16_t));
789 		if (!p)
790 			return -ENOMEM;
791 
792 		mutex_lock(&ca->set->bucket_lock);
793 		for_each_bucket(b, ca) {
794 			if (!GC_SECTORS_USED(b))
795 				unused++;
796 			if (GC_MARK(b) == GC_MARK_RECLAIMABLE)
797 				available++;
798 			if (GC_MARK(b) == GC_MARK_DIRTY)
799 				dirty++;
800 			if (GC_MARK(b) == GC_MARK_METADATA)
801 				meta++;
802 		}
803 
804 		for (i = ca->sb.first_bucket; i < n; i++)
805 			p[i] = ca->buckets[i].prio;
806 		mutex_unlock(&ca->set->bucket_lock);
807 
808 		sort(p, n, sizeof(uint16_t), __bch_cache_cmp, NULL);
809 
810 		while (n &&
811 		       !cached[n - 1])
812 			--n;
813 
814 		unused = ca->sb.nbuckets - n;
815 
816 		while (cached < p + n &&
817 		       *cached == BTREE_PRIO)
818 			cached++, n--;
819 
820 		for (i = 0; i < n; i++)
821 			sum += INITIAL_PRIO - cached[i];
822 
823 		if (n)
824 			do_div(sum, n);
825 
826 		for (i = 0; i < ARRAY_SIZE(q); i++)
827 			q[i] = INITIAL_PRIO - cached[n * (i + 1) /
828 				(ARRAY_SIZE(q) + 1)];
829 
830 		vfree(p);
831 
832 		ret = scnprintf(buf, PAGE_SIZE,
833 				"Unused:		%zu%%\n"
834 				"Clean:		%zu%%\n"
835 				"Dirty:		%zu%%\n"
836 				"Metadata:	%zu%%\n"
837 				"Average:	%llu\n"
838 				"Sectors per Q:	%zu\n"
839 				"Quantiles:	[",
840 				unused * 100 / (size_t) ca->sb.nbuckets,
841 				available * 100 / (size_t) ca->sb.nbuckets,
842 				dirty * 100 / (size_t) ca->sb.nbuckets,
843 				meta * 100 / (size_t) ca->sb.nbuckets, sum,
844 				n * ca->sb.bucket_size / (ARRAY_SIZE(q) + 1));
845 
846 		for (i = 0; i < ARRAY_SIZE(q); i++)
847 			ret += scnprintf(buf + ret, PAGE_SIZE - ret,
848 					 "%u ", q[i]);
849 		ret--;
850 
851 		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "]\n");
852 
853 		return ret;
854 	}
855 
856 	return 0;
857 }
858 SHOW_LOCKED(bch_cache)
859 
860 STORE(__bch_cache)
861 {
862 	struct cache *ca = container_of(kobj, struct cache, kobj);
863 
864 	if (attr == &sysfs_discard) {
865 		bool v = strtoul_or_return(buf);
866 
867 		if (blk_queue_discard(bdev_get_queue(ca->bdev)))
868 			ca->discard = v;
869 
870 		if (v != CACHE_DISCARD(&ca->sb)) {
871 			SET_CACHE_DISCARD(&ca->sb, v);
872 			bcache_write_super(ca->set);
873 		}
874 	}
875 
876 	if (attr == &sysfs_cache_replacement_policy) {
877 		ssize_t v = bch_read_string_list(buf, cache_replacement_policies);
878 
879 		if (v < 0)
880 			return v;
881 
882 		if ((unsigned) v != CACHE_REPLACEMENT(&ca->sb)) {
883 			mutex_lock(&ca->set->bucket_lock);
884 			SET_CACHE_REPLACEMENT(&ca->sb, v);
885 			mutex_unlock(&ca->set->bucket_lock);
886 
887 			bcache_write_super(ca->set);
888 		}
889 	}
890 
891 	if (attr == &sysfs_clear_stats) {
892 		atomic_long_set(&ca->sectors_written, 0);
893 		atomic_long_set(&ca->btree_sectors_written, 0);
894 		atomic_long_set(&ca->meta_sectors_written, 0);
895 		atomic_set(&ca->io_count, 0);
896 		atomic_set(&ca->io_errors, 0);
897 	}
898 
899 	return size;
900 }
901 STORE_LOCKED(bch_cache)
902 
903 static struct attribute *bch_cache_files[] = {
904 	&sysfs_bucket_size,
905 	&sysfs_block_size,
906 	&sysfs_nbuckets,
907 	&sysfs_priority_stats,
908 	&sysfs_discard,
909 	&sysfs_written,
910 	&sysfs_btree_written,
911 	&sysfs_metadata_written,
912 	&sysfs_io_errors,
913 	&sysfs_clear_stats,
914 	&sysfs_cache_replacement_policy,
915 	NULL
916 };
917 KTYPE(bch_cache);
918