xref: /openbmc/linux/drivers/md/bcache/sysfs.c (revision 48c926cd)
1 /*
2  * bcache sysfs interfaces
3  *
4  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
5  * Copyright 2012 Google, Inc.
6  */
7 
8 #include "bcache.h"
9 #include "sysfs.h"
10 #include "btree.h"
11 #include "request.h"
12 #include "writeback.h"
13 
14 #include <linux/blkdev.h>
15 #include <linux/sort.h>
16 #include <linux/sched/clock.h>
17 
18 static const char * const cache_replacement_policies[] = {
19 	"lru",
20 	"fifo",
21 	"random",
22 	NULL
23 };
24 
25 static const char * const error_actions[] = {
26 	"unregister",
27 	"panic",
28 	NULL
29 };
30 
31 write_attribute(attach);
32 write_attribute(detach);
33 write_attribute(unregister);
34 write_attribute(stop);
35 write_attribute(clear_stats);
36 write_attribute(trigger_gc);
37 write_attribute(prune_cache);
38 write_attribute(flash_vol_create);
39 
40 read_attribute(bucket_size);
41 read_attribute(block_size);
42 read_attribute(nbuckets);
43 read_attribute(tree_depth);
44 read_attribute(root_usage_percent);
45 read_attribute(priority_stats);
46 read_attribute(btree_cache_size);
47 read_attribute(btree_cache_max_chain);
48 read_attribute(cache_available_percent);
49 read_attribute(written);
50 read_attribute(btree_written);
51 read_attribute(metadata_written);
52 read_attribute(active_journal_entries);
53 
54 sysfs_time_stats_attribute(btree_gc,	sec, ms);
55 sysfs_time_stats_attribute(btree_split, sec, us);
56 sysfs_time_stats_attribute(btree_sort,	ms,  us);
57 sysfs_time_stats_attribute(btree_read,	ms,  us);
58 
59 read_attribute(btree_nodes);
60 read_attribute(btree_used_percent);
61 read_attribute(average_key_size);
62 read_attribute(dirty_data);
63 read_attribute(bset_tree_stats);
64 
65 read_attribute(state);
66 read_attribute(cache_read_races);
67 read_attribute(writeback_keys_done);
68 read_attribute(writeback_keys_failed);
69 read_attribute(io_errors);
70 read_attribute(congested);
71 rw_attribute(congested_read_threshold_us);
72 rw_attribute(congested_write_threshold_us);
73 
74 rw_attribute(sequential_cutoff);
75 rw_attribute(data_csum);
76 rw_attribute(cache_mode);
77 rw_attribute(writeback_metadata);
78 rw_attribute(writeback_running);
79 rw_attribute(writeback_percent);
80 rw_attribute(writeback_delay);
81 rw_attribute(writeback_rate);
82 
83 rw_attribute(writeback_rate_update_seconds);
84 rw_attribute(writeback_rate_d_term);
85 rw_attribute(writeback_rate_p_term_inverse);
86 read_attribute(writeback_rate_debug);
87 
88 read_attribute(stripe_size);
89 read_attribute(partial_stripes_expensive);
90 
91 rw_attribute(synchronous);
92 rw_attribute(journal_delay_ms);
93 rw_attribute(discard);
94 rw_attribute(running);
95 rw_attribute(label);
96 rw_attribute(readahead);
97 rw_attribute(errors);
98 rw_attribute(io_error_limit);
99 rw_attribute(io_error_halflife);
100 rw_attribute(verify);
101 rw_attribute(bypass_torture_test);
102 rw_attribute(key_merging_disabled);
103 rw_attribute(gc_always_rewrite);
104 rw_attribute(expensive_debug_checks);
105 rw_attribute(cache_replacement_policy);
106 rw_attribute(btree_shrinker_disabled);
107 rw_attribute(copy_gc_enabled);
108 rw_attribute(size);
109 
110 SHOW(__bch_cached_dev)
111 {
112 	struct cached_dev *dc = container_of(kobj, struct cached_dev,
113 					     disk.kobj);
114 	const char *states[] = { "no cache", "clean", "dirty", "inconsistent" };
115 
116 #define var(stat)		(dc->stat)
117 
118 	if (attr == &sysfs_cache_mode)
119 		return bch_snprint_string_list(buf, PAGE_SIZE,
120 					       bch_cache_modes + 1,
121 					       BDEV_CACHE_MODE(&dc->sb));
122 
123 	sysfs_printf(data_csum,		"%i", dc->disk.data_csum);
124 	var_printf(verify,		"%i");
125 	var_printf(bypass_torture_test,	"%i");
126 	var_printf(writeback_metadata,	"%i");
127 	var_printf(writeback_running,	"%i");
128 	var_print(writeback_delay);
129 	var_print(writeback_percent);
130 	sysfs_hprint(writeback_rate,	dc->writeback_rate.rate << 9);
131 
132 	var_print(writeback_rate_update_seconds);
133 	var_print(writeback_rate_d_term);
134 	var_print(writeback_rate_p_term_inverse);
135 
136 	if (attr == &sysfs_writeback_rate_debug) {
137 		char rate[20];
138 		char dirty[20];
139 		char target[20];
140 		char proportional[20];
141 		char derivative[20];
142 		char change[20];
143 		s64 next_io;
144 
145 		bch_hprint(rate,	dc->writeback_rate.rate << 9);
146 		bch_hprint(dirty,	bcache_dev_sectors_dirty(&dc->disk) << 9);
147 		bch_hprint(target,	dc->writeback_rate_target << 9);
148 		bch_hprint(proportional,dc->writeback_rate_proportional << 9);
149 		bch_hprint(derivative,	dc->writeback_rate_derivative << 9);
150 		bch_hprint(change,	dc->writeback_rate_change << 9);
151 
152 		next_io = div64_s64(dc->writeback_rate.next - local_clock(),
153 				    NSEC_PER_MSEC);
154 
155 		return sprintf(buf,
156 			       "rate:\t\t%s/sec\n"
157 			       "dirty:\t\t%s\n"
158 			       "target:\t\t%s\n"
159 			       "proportional:\t%s\n"
160 			       "derivative:\t%s\n"
161 			       "change:\t\t%s/sec\n"
162 			       "next io:\t%llims\n",
163 			       rate, dirty, target, proportional,
164 			       derivative, change, next_io);
165 	}
166 
167 	sysfs_hprint(dirty_data,
168 		     bcache_dev_sectors_dirty(&dc->disk) << 9);
169 
170 	sysfs_hprint(stripe_size,	dc->disk.stripe_size << 9);
171 	var_printf(partial_stripes_expensive,	"%u");
172 
173 	var_hprint(sequential_cutoff);
174 	var_hprint(readahead);
175 
176 	sysfs_print(running,		atomic_read(&dc->running));
177 	sysfs_print(state,		states[BDEV_STATE(&dc->sb)]);
178 
179 	if (attr == &sysfs_label) {
180 		memcpy(buf, dc->sb.label, SB_LABEL_SIZE);
181 		buf[SB_LABEL_SIZE + 1] = '\0';
182 		strcat(buf, "\n");
183 		return strlen(buf);
184 	}
185 
186 #undef var
187 	return 0;
188 }
189 SHOW_LOCKED(bch_cached_dev)
190 
191 STORE(__cached_dev)
192 {
193 	struct cached_dev *dc = container_of(kobj, struct cached_dev,
194 					     disk.kobj);
195 	ssize_t v = size;
196 	struct cache_set *c;
197 	struct kobj_uevent_env *env;
198 
199 #define d_strtoul(var)		sysfs_strtoul(var, dc->var)
200 #define d_strtoul_nonzero(var)	sysfs_strtoul_clamp(var, dc->var, 1, INT_MAX)
201 #define d_strtoi_h(var)		sysfs_hatoi(var, dc->var)
202 
203 	sysfs_strtoul(data_csum,	dc->disk.data_csum);
204 	d_strtoul(verify);
205 	d_strtoul(bypass_torture_test);
206 	d_strtoul(writeback_metadata);
207 	d_strtoul(writeback_running);
208 	d_strtoul(writeback_delay);
209 
210 	sysfs_strtoul_clamp(writeback_percent, dc->writeback_percent, 0, 40);
211 
212 	sysfs_strtoul_clamp(writeback_rate,
213 			    dc->writeback_rate.rate, 1, INT_MAX);
214 
215 	d_strtoul_nonzero(writeback_rate_update_seconds);
216 	d_strtoul(writeback_rate_d_term);
217 	d_strtoul_nonzero(writeback_rate_p_term_inverse);
218 
219 	d_strtoi_h(sequential_cutoff);
220 	d_strtoi_h(readahead);
221 
222 	if (attr == &sysfs_clear_stats)
223 		bch_cache_accounting_clear(&dc->accounting);
224 
225 	if (attr == &sysfs_running &&
226 	    strtoul_or_return(buf))
227 		bch_cached_dev_run(dc);
228 
229 	if (attr == &sysfs_cache_mode) {
230 		v = bch_read_string_list(buf, bch_cache_modes + 1);
231 
232 		if (v < 0)
233 			return v;
234 
235 		if ((unsigned) v != BDEV_CACHE_MODE(&dc->sb)) {
236 			SET_BDEV_CACHE_MODE(&dc->sb, v);
237 			bch_write_bdev_super(dc, NULL);
238 		}
239 	}
240 
241 	if (attr == &sysfs_label) {
242 		if (size > SB_LABEL_SIZE)
243 			return -EINVAL;
244 		memcpy(dc->sb.label, buf, size);
245 		if (size < SB_LABEL_SIZE)
246 			dc->sb.label[size] = '\0';
247 		if (size && dc->sb.label[size - 1] == '\n')
248 			dc->sb.label[size - 1] = '\0';
249 		bch_write_bdev_super(dc, NULL);
250 		if (dc->disk.c) {
251 			memcpy(dc->disk.c->uuids[dc->disk.id].label,
252 			       buf, SB_LABEL_SIZE);
253 			bch_uuid_write(dc->disk.c);
254 		}
255 		env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
256 		if (!env)
257 			return -ENOMEM;
258 		add_uevent_var(env, "DRIVER=bcache");
259 		add_uevent_var(env, "CACHED_UUID=%pU", dc->sb.uuid),
260 		add_uevent_var(env, "CACHED_LABEL=%s", buf);
261 		kobject_uevent_env(
262 			&disk_to_dev(dc->disk.disk)->kobj, KOBJ_CHANGE, env->envp);
263 		kfree(env);
264 	}
265 
266 	if (attr == &sysfs_attach) {
267 		if (bch_parse_uuid(buf, dc->sb.set_uuid) < 16)
268 			return -EINVAL;
269 
270 		list_for_each_entry(c, &bch_cache_sets, list) {
271 			v = bch_cached_dev_attach(dc, c);
272 			if (!v)
273 				return size;
274 		}
275 
276 		pr_err("Can't attach %s: cache set not found", buf);
277 		size = v;
278 	}
279 
280 	if (attr == &sysfs_detach && dc->disk.c)
281 		bch_cached_dev_detach(dc);
282 
283 	if (attr == &sysfs_stop)
284 		bcache_device_stop(&dc->disk);
285 
286 	return size;
287 }
288 
289 STORE(bch_cached_dev)
290 {
291 	struct cached_dev *dc = container_of(kobj, struct cached_dev,
292 					     disk.kobj);
293 
294 	mutex_lock(&bch_register_lock);
295 	size = __cached_dev_store(kobj, attr, buf, size);
296 
297 	if (attr == &sysfs_writeback_running)
298 		bch_writeback_queue(dc);
299 
300 	if (attr == &sysfs_writeback_percent)
301 		schedule_delayed_work(&dc->writeback_rate_update,
302 				      dc->writeback_rate_update_seconds * HZ);
303 
304 	mutex_unlock(&bch_register_lock);
305 	return size;
306 }
307 
308 static struct attribute *bch_cached_dev_files[] = {
309 	&sysfs_attach,
310 	&sysfs_detach,
311 	&sysfs_stop,
312 #if 0
313 	&sysfs_data_csum,
314 #endif
315 	&sysfs_cache_mode,
316 	&sysfs_writeback_metadata,
317 	&sysfs_writeback_running,
318 	&sysfs_writeback_delay,
319 	&sysfs_writeback_percent,
320 	&sysfs_writeback_rate,
321 	&sysfs_writeback_rate_update_seconds,
322 	&sysfs_writeback_rate_d_term,
323 	&sysfs_writeback_rate_p_term_inverse,
324 	&sysfs_writeback_rate_debug,
325 	&sysfs_dirty_data,
326 	&sysfs_stripe_size,
327 	&sysfs_partial_stripes_expensive,
328 	&sysfs_sequential_cutoff,
329 	&sysfs_clear_stats,
330 	&sysfs_running,
331 	&sysfs_state,
332 	&sysfs_label,
333 	&sysfs_readahead,
334 #ifdef CONFIG_BCACHE_DEBUG
335 	&sysfs_verify,
336 	&sysfs_bypass_torture_test,
337 #endif
338 	NULL
339 };
340 KTYPE(bch_cached_dev);
341 
342 SHOW(bch_flash_dev)
343 {
344 	struct bcache_device *d = container_of(kobj, struct bcache_device,
345 					       kobj);
346 	struct uuid_entry *u = &d->c->uuids[d->id];
347 
348 	sysfs_printf(data_csum,	"%i", d->data_csum);
349 	sysfs_hprint(size,	u->sectors << 9);
350 
351 	if (attr == &sysfs_label) {
352 		memcpy(buf, u->label, SB_LABEL_SIZE);
353 		buf[SB_LABEL_SIZE + 1] = '\0';
354 		strcat(buf, "\n");
355 		return strlen(buf);
356 	}
357 
358 	return 0;
359 }
360 
361 STORE(__bch_flash_dev)
362 {
363 	struct bcache_device *d = container_of(kobj, struct bcache_device,
364 					       kobj);
365 	struct uuid_entry *u = &d->c->uuids[d->id];
366 
367 	sysfs_strtoul(data_csum,	d->data_csum);
368 
369 	if (attr == &sysfs_size) {
370 		uint64_t v;
371 		strtoi_h_or_return(buf, v);
372 
373 		u->sectors = v >> 9;
374 		bch_uuid_write(d->c);
375 		set_capacity(d->disk, u->sectors);
376 	}
377 
378 	if (attr == &sysfs_label) {
379 		memcpy(u->label, buf, SB_LABEL_SIZE);
380 		bch_uuid_write(d->c);
381 	}
382 
383 	if (attr == &sysfs_unregister) {
384 		set_bit(BCACHE_DEV_DETACHING, &d->flags);
385 		bcache_device_stop(d);
386 	}
387 
388 	return size;
389 }
390 STORE_LOCKED(bch_flash_dev)
391 
392 static struct attribute *bch_flash_dev_files[] = {
393 	&sysfs_unregister,
394 #if 0
395 	&sysfs_data_csum,
396 #endif
397 	&sysfs_label,
398 	&sysfs_size,
399 	NULL
400 };
401 KTYPE(bch_flash_dev);
402 
403 struct bset_stats_op {
404 	struct btree_op op;
405 	size_t nodes;
406 	struct bset_stats stats;
407 };
408 
409 static int bch_btree_bset_stats(struct btree_op *b_op, struct btree *b)
410 {
411 	struct bset_stats_op *op = container_of(b_op, struct bset_stats_op, op);
412 
413 	op->nodes++;
414 	bch_btree_keys_stats(&b->keys, &op->stats);
415 
416 	return MAP_CONTINUE;
417 }
418 
419 static int bch_bset_print_stats(struct cache_set *c, char *buf)
420 {
421 	struct bset_stats_op op;
422 	int ret;
423 
424 	memset(&op, 0, sizeof(op));
425 	bch_btree_op_init(&op.op, -1);
426 
427 	ret = bch_btree_map_nodes(&op.op, c, &ZERO_KEY, bch_btree_bset_stats);
428 	if (ret < 0)
429 		return ret;
430 
431 	return snprintf(buf, PAGE_SIZE,
432 			"btree nodes:		%zu\n"
433 			"written sets:		%zu\n"
434 			"unwritten sets:		%zu\n"
435 			"written key bytes:	%zu\n"
436 			"unwritten key bytes:	%zu\n"
437 			"floats:			%zu\n"
438 			"failed:			%zu\n",
439 			op.nodes,
440 			op.stats.sets_written, op.stats.sets_unwritten,
441 			op.stats.bytes_written, op.stats.bytes_unwritten,
442 			op.stats.floats, op.stats.failed);
443 }
444 
445 static unsigned bch_root_usage(struct cache_set *c)
446 {
447 	unsigned bytes = 0;
448 	struct bkey *k;
449 	struct btree *b;
450 	struct btree_iter iter;
451 
452 	goto lock_root;
453 
454 	do {
455 		rw_unlock(false, b);
456 lock_root:
457 		b = c->root;
458 		rw_lock(false, b, b->level);
459 	} while (b != c->root);
460 
461 	for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
462 		bytes += bkey_bytes(k);
463 
464 	rw_unlock(false, b);
465 
466 	return (bytes * 100) / btree_bytes(c);
467 }
468 
469 static size_t bch_cache_size(struct cache_set *c)
470 {
471 	size_t ret = 0;
472 	struct btree *b;
473 
474 	mutex_lock(&c->bucket_lock);
475 	list_for_each_entry(b, &c->btree_cache, list)
476 		ret += 1 << (b->keys.page_order + PAGE_SHIFT);
477 
478 	mutex_unlock(&c->bucket_lock);
479 	return ret;
480 }
481 
482 static unsigned bch_cache_max_chain(struct cache_set *c)
483 {
484 	unsigned ret = 0;
485 	struct hlist_head *h;
486 
487 	mutex_lock(&c->bucket_lock);
488 
489 	for (h = c->bucket_hash;
490 	     h < c->bucket_hash + (1 << BUCKET_HASH_BITS);
491 	     h++) {
492 		unsigned i = 0;
493 		struct hlist_node *p;
494 
495 		hlist_for_each(p, h)
496 			i++;
497 
498 		ret = max(ret, i);
499 	}
500 
501 	mutex_unlock(&c->bucket_lock);
502 	return ret;
503 }
504 
505 static unsigned bch_btree_used(struct cache_set *c)
506 {
507 	return div64_u64(c->gc_stats.key_bytes * 100,
508 			 (c->gc_stats.nodes ?: 1) * btree_bytes(c));
509 }
510 
511 static unsigned bch_average_key_size(struct cache_set *c)
512 {
513 	return c->gc_stats.nkeys
514 		? div64_u64(c->gc_stats.data, c->gc_stats.nkeys)
515 		: 0;
516 }
517 
518 SHOW(__bch_cache_set)
519 {
520 	struct cache_set *c = container_of(kobj, struct cache_set, kobj);
521 
522 	sysfs_print(synchronous,		CACHE_SYNC(&c->sb));
523 	sysfs_print(journal_delay_ms,		c->journal_delay_ms);
524 	sysfs_hprint(bucket_size,		bucket_bytes(c));
525 	sysfs_hprint(block_size,		block_bytes(c));
526 	sysfs_print(tree_depth,			c->root->level);
527 	sysfs_print(root_usage_percent,		bch_root_usage(c));
528 
529 	sysfs_hprint(btree_cache_size,		bch_cache_size(c));
530 	sysfs_print(btree_cache_max_chain,	bch_cache_max_chain(c));
531 	sysfs_print(cache_available_percent,	100 - c->gc_stats.in_use);
532 
533 	sysfs_print_time_stats(&c->btree_gc_time,	btree_gc, sec, ms);
534 	sysfs_print_time_stats(&c->btree_split_time,	btree_split, sec, us);
535 	sysfs_print_time_stats(&c->sort.time,		btree_sort, ms, us);
536 	sysfs_print_time_stats(&c->btree_read_time,	btree_read, ms, us);
537 
538 	sysfs_print(btree_used_percent,	bch_btree_used(c));
539 	sysfs_print(btree_nodes,	c->gc_stats.nodes);
540 	sysfs_hprint(average_key_size,	bch_average_key_size(c));
541 
542 	sysfs_print(cache_read_races,
543 		    atomic_long_read(&c->cache_read_races));
544 
545 	sysfs_print(writeback_keys_done,
546 		    atomic_long_read(&c->writeback_keys_done));
547 	sysfs_print(writeback_keys_failed,
548 		    atomic_long_read(&c->writeback_keys_failed));
549 
550 	if (attr == &sysfs_errors)
551 		return bch_snprint_string_list(buf, PAGE_SIZE, error_actions,
552 					       c->on_error);
553 
554 	/* See count_io_errors for why 88 */
555 	sysfs_print(io_error_halflife,	c->error_decay * 88);
556 	sysfs_print(io_error_limit,	c->error_limit >> IO_ERROR_SHIFT);
557 
558 	sysfs_hprint(congested,
559 		     ((uint64_t) bch_get_congested(c)) << 9);
560 	sysfs_print(congested_read_threshold_us,
561 		    c->congested_read_threshold_us);
562 	sysfs_print(congested_write_threshold_us,
563 		    c->congested_write_threshold_us);
564 
565 	sysfs_print(active_journal_entries,	fifo_used(&c->journal.pin));
566 	sysfs_printf(verify,			"%i", c->verify);
567 	sysfs_printf(key_merging_disabled,	"%i", c->key_merging_disabled);
568 	sysfs_printf(expensive_debug_checks,
569 		     "%i", c->expensive_debug_checks);
570 	sysfs_printf(gc_always_rewrite,		"%i", c->gc_always_rewrite);
571 	sysfs_printf(btree_shrinker_disabled,	"%i", c->shrinker_disabled);
572 	sysfs_printf(copy_gc_enabled,		"%i", c->copy_gc_enabled);
573 
574 	if (attr == &sysfs_bset_tree_stats)
575 		return bch_bset_print_stats(c, buf);
576 
577 	return 0;
578 }
579 SHOW_LOCKED(bch_cache_set)
580 
581 STORE(__bch_cache_set)
582 {
583 	struct cache_set *c = container_of(kobj, struct cache_set, kobj);
584 
585 	if (attr == &sysfs_unregister)
586 		bch_cache_set_unregister(c);
587 
588 	if (attr == &sysfs_stop)
589 		bch_cache_set_stop(c);
590 
591 	if (attr == &sysfs_synchronous) {
592 		bool sync = strtoul_or_return(buf);
593 
594 		if (sync != CACHE_SYNC(&c->sb)) {
595 			SET_CACHE_SYNC(&c->sb, sync);
596 			bcache_write_super(c);
597 		}
598 	}
599 
600 	if (attr == &sysfs_flash_vol_create) {
601 		int r;
602 		uint64_t v;
603 		strtoi_h_or_return(buf, v);
604 
605 		r = bch_flash_dev_create(c, v);
606 		if (r)
607 			return r;
608 	}
609 
610 	if (attr == &sysfs_clear_stats) {
611 		atomic_long_set(&c->writeback_keys_done,	0);
612 		atomic_long_set(&c->writeback_keys_failed,	0);
613 
614 		memset(&c->gc_stats, 0, sizeof(struct gc_stat));
615 		bch_cache_accounting_clear(&c->accounting);
616 	}
617 
618 	if (attr == &sysfs_trigger_gc) {
619 		/*
620 		 * Garbage collection thread only works when sectors_to_gc < 0,
621 		 * when users write to sysfs entry trigger_gc, most of time
622 		 * they want to forcibly triger gargage collection. Here -1 is
623 		 * set to c->sectors_to_gc, to make gc_should_run() give a
624 		 * chance to permit gc thread to run. "give a chance" means
625 		 * before going into gc_should_run(), there is still chance
626 		 * that c->sectors_to_gc being set to other positive value. So
627 		 * writing sysfs entry trigger_gc won't always make sure gc
628 		 * thread takes effect.
629 		 */
630 		atomic_set(&c->sectors_to_gc, -1);
631 		wake_up_gc(c);
632 	}
633 
634 	if (attr == &sysfs_prune_cache) {
635 		struct shrink_control sc;
636 		sc.gfp_mask = GFP_KERNEL;
637 		sc.nr_to_scan = strtoul_or_return(buf);
638 		c->shrink.scan_objects(&c->shrink, &sc);
639 	}
640 
641 	sysfs_strtoul(congested_read_threshold_us,
642 		      c->congested_read_threshold_us);
643 	sysfs_strtoul(congested_write_threshold_us,
644 		      c->congested_write_threshold_us);
645 
646 	if (attr == &sysfs_errors) {
647 		ssize_t v = bch_read_string_list(buf, error_actions);
648 
649 		if (v < 0)
650 			return v;
651 
652 		c->on_error = v;
653 	}
654 
655 	if (attr == &sysfs_io_error_limit)
656 		c->error_limit = strtoul_or_return(buf) << IO_ERROR_SHIFT;
657 
658 	/* See count_io_errors() for why 88 */
659 	if (attr == &sysfs_io_error_halflife)
660 		c->error_decay = strtoul_or_return(buf) / 88;
661 
662 	sysfs_strtoul(journal_delay_ms,		c->journal_delay_ms);
663 	sysfs_strtoul(verify,			c->verify);
664 	sysfs_strtoul(key_merging_disabled,	c->key_merging_disabled);
665 	sysfs_strtoul(expensive_debug_checks,	c->expensive_debug_checks);
666 	sysfs_strtoul(gc_always_rewrite,	c->gc_always_rewrite);
667 	sysfs_strtoul(btree_shrinker_disabled,	c->shrinker_disabled);
668 	sysfs_strtoul(copy_gc_enabled,		c->copy_gc_enabled);
669 
670 	return size;
671 }
672 STORE_LOCKED(bch_cache_set)
673 
674 SHOW(bch_cache_set_internal)
675 {
676 	struct cache_set *c = container_of(kobj, struct cache_set, internal);
677 	return bch_cache_set_show(&c->kobj, attr, buf);
678 }
679 
680 STORE(bch_cache_set_internal)
681 {
682 	struct cache_set *c = container_of(kobj, struct cache_set, internal);
683 	return bch_cache_set_store(&c->kobj, attr, buf, size);
684 }
685 
686 static void bch_cache_set_internal_release(struct kobject *k)
687 {
688 }
689 
690 static struct attribute *bch_cache_set_files[] = {
691 	&sysfs_unregister,
692 	&sysfs_stop,
693 	&sysfs_synchronous,
694 	&sysfs_journal_delay_ms,
695 	&sysfs_flash_vol_create,
696 
697 	&sysfs_bucket_size,
698 	&sysfs_block_size,
699 	&sysfs_tree_depth,
700 	&sysfs_root_usage_percent,
701 	&sysfs_btree_cache_size,
702 	&sysfs_cache_available_percent,
703 
704 	&sysfs_average_key_size,
705 
706 	&sysfs_errors,
707 	&sysfs_io_error_limit,
708 	&sysfs_io_error_halflife,
709 	&sysfs_congested,
710 	&sysfs_congested_read_threshold_us,
711 	&sysfs_congested_write_threshold_us,
712 	&sysfs_clear_stats,
713 	NULL
714 };
715 KTYPE(bch_cache_set);
716 
717 static struct attribute *bch_cache_set_internal_files[] = {
718 	&sysfs_active_journal_entries,
719 
720 	sysfs_time_stats_attribute_list(btree_gc, sec, ms)
721 	sysfs_time_stats_attribute_list(btree_split, sec, us)
722 	sysfs_time_stats_attribute_list(btree_sort, ms, us)
723 	sysfs_time_stats_attribute_list(btree_read, ms, us)
724 
725 	&sysfs_btree_nodes,
726 	&sysfs_btree_used_percent,
727 	&sysfs_btree_cache_max_chain,
728 
729 	&sysfs_bset_tree_stats,
730 	&sysfs_cache_read_races,
731 	&sysfs_writeback_keys_done,
732 	&sysfs_writeback_keys_failed,
733 
734 	&sysfs_trigger_gc,
735 	&sysfs_prune_cache,
736 #ifdef CONFIG_BCACHE_DEBUG
737 	&sysfs_verify,
738 	&sysfs_key_merging_disabled,
739 	&sysfs_expensive_debug_checks,
740 #endif
741 	&sysfs_gc_always_rewrite,
742 	&sysfs_btree_shrinker_disabled,
743 	&sysfs_copy_gc_enabled,
744 	NULL
745 };
746 KTYPE(bch_cache_set_internal);
747 
748 SHOW(__bch_cache)
749 {
750 	struct cache *ca = container_of(kobj, struct cache, kobj);
751 
752 	sysfs_hprint(bucket_size,	bucket_bytes(ca));
753 	sysfs_hprint(block_size,	block_bytes(ca));
754 	sysfs_print(nbuckets,		ca->sb.nbuckets);
755 	sysfs_print(discard,		ca->discard);
756 	sysfs_hprint(written, atomic_long_read(&ca->sectors_written) << 9);
757 	sysfs_hprint(btree_written,
758 		     atomic_long_read(&ca->btree_sectors_written) << 9);
759 	sysfs_hprint(metadata_written,
760 		     (atomic_long_read(&ca->meta_sectors_written) +
761 		      atomic_long_read(&ca->btree_sectors_written)) << 9);
762 
763 	sysfs_print(io_errors,
764 		    atomic_read(&ca->io_errors) >> IO_ERROR_SHIFT);
765 
766 	if (attr == &sysfs_cache_replacement_policy)
767 		return bch_snprint_string_list(buf, PAGE_SIZE,
768 					       cache_replacement_policies,
769 					       CACHE_REPLACEMENT(&ca->sb));
770 
771 	if (attr == &sysfs_priority_stats) {
772 		int cmp(const void *l, const void *r)
773 		{	return *((uint16_t *) r) - *((uint16_t *) l); }
774 
775 		struct bucket *b;
776 		size_t n = ca->sb.nbuckets, i;
777 		size_t unused = 0, available = 0, dirty = 0, meta = 0;
778 		uint64_t sum = 0;
779 		/* Compute 31 quantiles */
780 		uint16_t q[31], *p, *cached;
781 		ssize_t ret;
782 
783 		cached = p = vmalloc(ca->sb.nbuckets * sizeof(uint16_t));
784 		if (!p)
785 			return -ENOMEM;
786 
787 		mutex_lock(&ca->set->bucket_lock);
788 		for_each_bucket(b, ca) {
789 			if (!GC_SECTORS_USED(b))
790 				unused++;
791 			if (GC_MARK(b) == GC_MARK_RECLAIMABLE)
792 				available++;
793 			if (GC_MARK(b) == GC_MARK_DIRTY)
794 				dirty++;
795 			if (GC_MARK(b) == GC_MARK_METADATA)
796 				meta++;
797 		}
798 
799 		for (i = ca->sb.first_bucket; i < n; i++)
800 			p[i] = ca->buckets[i].prio;
801 		mutex_unlock(&ca->set->bucket_lock);
802 
803 		sort(p, n, sizeof(uint16_t), cmp, NULL);
804 
805 		while (n &&
806 		       !cached[n - 1])
807 			--n;
808 
809 		unused = ca->sb.nbuckets - n;
810 
811 		while (cached < p + n &&
812 		       *cached == BTREE_PRIO)
813 			cached++, n--;
814 
815 		for (i = 0; i < n; i++)
816 			sum += INITIAL_PRIO - cached[i];
817 
818 		if (n)
819 			do_div(sum, n);
820 
821 		for (i = 0; i < ARRAY_SIZE(q); i++)
822 			q[i] = INITIAL_PRIO - cached[n * (i + 1) /
823 				(ARRAY_SIZE(q) + 1)];
824 
825 		vfree(p);
826 
827 		ret = scnprintf(buf, PAGE_SIZE,
828 				"Unused:		%zu%%\n"
829 				"Clean:		%zu%%\n"
830 				"Dirty:		%zu%%\n"
831 				"Metadata:	%zu%%\n"
832 				"Average:	%llu\n"
833 				"Sectors per Q:	%zu\n"
834 				"Quantiles:	[",
835 				unused * 100 / (size_t) ca->sb.nbuckets,
836 				available * 100 / (size_t) ca->sb.nbuckets,
837 				dirty * 100 / (size_t) ca->sb.nbuckets,
838 				meta * 100 / (size_t) ca->sb.nbuckets, sum,
839 				n * ca->sb.bucket_size / (ARRAY_SIZE(q) + 1));
840 
841 		for (i = 0; i < ARRAY_SIZE(q); i++)
842 			ret += scnprintf(buf + ret, PAGE_SIZE - ret,
843 					 "%u ", q[i]);
844 		ret--;
845 
846 		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "]\n");
847 
848 		return ret;
849 	}
850 
851 	return 0;
852 }
853 SHOW_LOCKED(bch_cache)
854 
855 STORE(__bch_cache)
856 {
857 	struct cache *ca = container_of(kobj, struct cache, kobj);
858 
859 	if (attr == &sysfs_discard) {
860 		bool v = strtoul_or_return(buf);
861 
862 		if (blk_queue_discard(bdev_get_queue(ca->bdev)))
863 			ca->discard = v;
864 
865 		if (v != CACHE_DISCARD(&ca->sb)) {
866 			SET_CACHE_DISCARD(&ca->sb, v);
867 			bcache_write_super(ca->set);
868 		}
869 	}
870 
871 	if (attr == &sysfs_cache_replacement_policy) {
872 		ssize_t v = bch_read_string_list(buf, cache_replacement_policies);
873 
874 		if (v < 0)
875 			return v;
876 
877 		if ((unsigned) v != CACHE_REPLACEMENT(&ca->sb)) {
878 			mutex_lock(&ca->set->bucket_lock);
879 			SET_CACHE_REPLACEMENT(&ca->sb, v);
880 			mutex_unlock(&ca->set->bucket_lock);
881 
882 			bcache_write_super(ca->set);
883 		}
884 	}
885 
886 	if (attr == &sysfs_clear_stats) {
887 		atomic_long_set(&ca->sectors_written, 0);
888 		atomic_long_set(&ca->btree_sectors_written, 0);
889 		atomic_long_set(&ca->meta_sectors_written, 0);
890 		atomic_set(&ca->io_count, 0);
891 		atomic_set(&ca->io_errors, 0);
892 	}
893 
894 	return size;
895 }
896 STORE_LOCKED(bch_cache)
897 
898 static struct attribute *bch_cache_files[] = {
899 	&sysfs_bucket_size,
900 	&sysfs_block_size,
901 	&sysfs_nbuckets,
902 	&sysfs_priority_stats,
903 	&sysfs_discard,
904 	&sysfs_written,
905 	&sysfs_btree_written,
906 	&sysfs_metadata_written,
907 	&sysfs_io_errors,
908 	&sysfs_clear_stats,
909 	&sysfs_cache_replacement_policy,
910 	NULL
911 };
912 KTYPE(bch_cache);
913