/*
   * bcache sysfs interfaces
   *
   * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
   * Copyright 2012 Google, Inc.
   */
  
  #include "bcache.h"
  #include "sysfs.h"
  #include "btree.h"
  #include "request.h"

  #include "writeback.h"

  #include <linux/blkdev.h>

  #include <linux/sort.h>
  
  static const char * const cache_replacement_policies[] = {
  	"lru",
  	"fifo",
  	"random",
  	NULL
  };

  static const char * const error_actions[] = {
  	"unregister",
  	"panic",
  	NULL
  };

  write_attribute(attach);
  write_attribute(detach);
  write_attribute(unregister);
  write_attribute(stop);
  write_attribute(clear_stats);
  write_attribute(trigger_gc);
  write_attribute(prune_cache);
  write_attribute(flash_vol_create);
  
  read_attribute(bucket_size);
  read_attribute(block_size);
  read_attribute(nbuckets);
  read_attribute(tree_depth);
  read_attribute(root_usage_percent);
  read_attribute(priority_stats);
  read_attribute(btree_cache_size);
  read_attribute(btree_cache_max_chain);
  read_attribute(cache_available_percent);
  read_attribute(written);
  read_attribute(btree_written);
  read_attribute(metadata_written);
  read_attribute(active_journal_entries);
  
  sysfs_time_stats_attribute(btree_gc,	sec, ms);
  sysfs_time_stats_attribute(btree_split, sec, us);
  sysfs_time_stats_attribute(btree_sort,	ms,  us);
  sysfs_time_stats_attribute(btree_read,	ms,  us);

  
  read_attribute(btree_nodes);
  read_attribute(btree_used_percent);
  read_attribute(average_key_size);
  read_attribute(dirty_data);
  read_attribute(bset_tree_stats);
  
  read_attribute(state);
  read_attribute(cache_read_races);
  read_attribute(writeback_keys_done);
  read_attribute(writeback_keys_failed);
  read_attribute(io_errors);
  read_attribute(congested);
  rw_attribute(congested_read_threshold_us);
  rw_attribute(congested_write_threshold_us);
  
  rw_attribute(sequential_cutoff);

  rw_attribute(data_csum);
  rw_attribute(cache_mode);
  rw_attribute(writeback_metadata);
  rw_attribute(writeback_running);
  rw_attribute(writeback_percent);
  rw_attribute(writeback_delay);
  rw_attribute(writeback_rate);
  
  rw_attribute(writeback_rate_update_seconds);
  rw_attribute(writeback_rate_d_term);
  rw_attribute(writeback_rate_p_term_inverse);

  read_attribute(writeback_rate_debug);

  read_attribute(stripe_size);
  read_attribute(partial_stripes_expensive);

  rw_attribute(synchronous);
  rw_attribute(journal_delay_ms);
  rw_attribute(discard);
  rw_attribute(running);
  rw_attribute(label);
  rw_attribute(readahead);

  rw_attribute(errors);

  rw_attribute(io_error_limit);
  rw_attribute(io_error_halflife);
  rw_attribute(verify);

  rw_attribute(bypass_torture_test);

  rw_attribute(key_merging_disabled);
  rw_attribute(gc_always_rewrite);

  rw_attribute(expensive_debug_checks);

  rw_attribute(cache_replacement_policy);
  rw_attribute(btree_shrinker_disabled);
  rw_attribute(copy_gc_enabled);
  rw_attribute(size);
  
  SHOW(__bch_cached_dev)
  {
  	struct cached_dev *dc = container_of(kobj, struct cached_dev,
  					     disk.kobj);
  	const char *states[] = { "no cache", "clean", "dirty", "inconsistent" };
  
  #define var(stat)		(dc->stat)
  
  	if (attr == &sysfs_cache_mode)

  		return bch_snprint_string_list(buf, PAGE_SIZE,
  					       bch_cache_modes + 1,
  					       BDEV_CACHE_MODE(&dc->sb));

  
  	sysfs_printf(data_csum,		"%i", dc->disk.data_csum);
  	var_printf(verify,		"%i");

  	var_printf(bypass_torture_test,	"%i");

  	var_printf(writeback_metadata,	"%i");
  	var_printf(writeback_running,	"%i");
  	var_print(writeback_delay);
  	var_print(writeback_percent);

  	sysfs_hprint(writeback_rate,	dc->writeback_rate.rate << 9);

  
  	var_print(writeback_rate_update_seconds);
  	var_print(writeback_rate_d_term);
  	var_print(writeback_rate_p_term_inverse);

  
  	if (attr == &sysfs_writeback_rate_debug) {

  		char rate[20];

  		char dirty[20];

  		char target[20];

  		char proportional[20];
  		char derivative[20];
  		char change[20];
  		s64 next_io;
  
  		bch_hprint(rate,	dc->writeback_rate.rate << 9);
  		bch_hprint(dirty,	bcache_dev_sectors_dirty(&dc->disk) << 9);

  		bch_hprint(target,	dc->writeback_rate_target << 9);

  		bch_hprint(proportional,dc->writeback_rate_proportional << 9);
  		bch_hprint(derivative,	dc->writeback_rate_derivative << 9);
  		bch_hprint(change,	dc->writeback_rate_change << 9);
  
  		next_io = div64_s64(dc->writeback_rate.next - local_clock(),
  				    NSEC_PER_MSEC);

  
  		return sprintf(buf,

  			       "rate:\t\t%s/sec
  "

  			       "dirty:\t\t%s
  "

  			       "target:\t\t%s
  "
  			       "proportional:\t%s
  "

  			       "derivative:\t%s
  "

  			       "change:\t\t%s/sec
  "
  			       "next io:\t%llims
  ",
  			       rate, dirty, target, proportional,
  			       derivative, change, next_io);

  	}
  
  	sysfs_hprint(dirty_data,

  		     bcache_dev_sectors_dirty(&dc->disk) << 9);

  	sysfs_hprint(stripe_size,	dc->disk.stripe_size << 9);

  	var_printf(partial_stripes_expensive,	"%u");

  	var_hprint(sequential_cutoff);
  	var_hprint(readahead);
  
  	sysfs_print(running,		atomic_read(&dc->running));
  	sysfs_print(state,		states[BDEV_STATE(&dc->sb)]);
  
  	if (attr == &sysfs_label) {
  		memcpy(buf, dc->sb.label, SB_LABEL_SIZE);
  		buf[SB_LABEL_SIZE + 1] = '\0';
  		strcat(buf, "
  ");
  		return strlen(buf);
  	}
  
  #undef var
  	return 0;
  }
  SHOW_LOCKED(bch_cached_dev)
  
  STORE(__cached_dev)
  {
  	struct cached_dev *dc = container_of(kobj, struct cached_dev,
  					     disk.kobj);
  	unsigned v = size;
  	struct cache_set *c;

  	struct kobj_uevent_env *env;

  
  #define d_strtoul(var)		sysfs_strtoul(var, dc->var)

  #define d_strtoul_nonzero(var)	sysfs_strtoul_clamp(var, dc->var, 1, INT_MAX)

  #define d_strtoi_h(var)		sysfs_hatoi(var, dc->var)
  
  	sysfs_strtoul(data_csum,	dc->disk.data_csum);
  	d_strtoul(verify);

  	d_strtoul(bypass_torture_test);

  	d_strtoul(writeback_metadata);
  	d_strtoul(writeback_running);
  	d_strtoul(writeback_delay);

  	sysfs_strtoul_clamp(writeback_percent, dc->writeback_percent, 0, 40);

  	sysfs_strtoul_clamp(writeback_rate,
  			    dc->writeback_rate.rate, 1, INT_MAX);
  
  	d_strtoul_nonzero(writeback_rate_update_seconds);

  	d_strtoul(writeback_rate_d_term);

  	d_strtoul_nonzero(writeback_rate_p_term_inverse);

  	d_strtoi_h(sequential_cutoff);
  	d_strtoi_h(readahead);
  
  	if (attr == &sysfs_clear_stats)
  		bch_cache_accounting_clear(&dc->accounting);
  
  	if (attr == &sysfs_running &&
  	    strtoul_or_return(buf))
  		bch_cached_dev_run(dc);
  
  	if (attr == &sysfs_cache_mode) {

  		ssize_t v = bch_read_string_list(buf, bch_cache_modes + 1);

  
  		if (v < 0)
  			return v;
  
  		if ((unsigned) v != BDEV_CACHE_MODE(&dc->sb)) {
  			SET_BDEV_CACHE_MODE(&dc->sb, v);
  			bch_write_bdev_super(dc, NULL);
  		}
  	}
  
  	if (attr == &sysfs_label) {

  		if (size > SB_LABEL_SIZE)
  			return -EINVAL;
  		memcpy(dc->sb.label, buf, size);
  		if (size < SB_LABEL_SIZE)
  			dc->sb.label[size] = '\0';
  		if (size && dc->sb.label[size - 1] == '
  ')
  			dc->sb.label[size - 1] = '\0';

  		bch_write_bdev_super(dc, NULL);
  		if (dc->disk.c) {
  			memcpy(dc->disk.c->uuids[dc->disk.id].label,
  			       buf, SB_LABEL_SIZE);
  			bch_uuid_write(dc->disk.c);
  		}

  		env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);

  		if (!env)
  			return -ENOMEM;

  		add_uevent_var(env, "DRIVER=bcache");
  		add_uevent_var(env, "CACHED_UUID=%pU", dc->sb.uuid),
  		add_uevent_var(env, "CACHED_LABEL=%s", buf);
  		kobject_uevent_env(
  			&disk_to_dev(dc->disk.disk)->kobj, KOBJ_CHANGE, env->envp);
  		kfree(env);

  	}
  
  	if (attr == &sysfs_attach) {

  		if (bch_parse_uuid(buf, dc->sb.set_uuid) < 16)

  			return -EINVAL;
  
  		list_for_each_entry(c, &bch_cache_sets, list) {
  			v = bch_cached_dev_attach(dc, c);
  			if (!v)
  				return size;
  		}
  
  		pr_err("Can't attach %s: cache set not found", buf);
  		size = v;
  	}
  
  	if (attr == &sysfs_detach && dc->disk.c)
  		bch_cached_dev_detach(dc);
  
  	if (attr == &sysfs_stop)
  		bcache_device_stop(&dc->disk);
  
  	return size;
  }
  
  STORE(bch_cached_dev)
  {
  	struct cached_dev *dc = container_of(kobj, struct cached_dev,
  					     disk.kobj);
  
  	mutex_lock(&bch_register_lock);
  	size = __cached_dev_store(kobj, attr, buf, size);
  
  	if (attr == &sysfs_writeback_running)
  		bch_writeback_queue(dc);
  
  	if (attr == &sysfs_writeback_percent)
  		schedule_delayed_work(&dc->writeback_rate_update,
  				      dc->writeback_rate_update_seconds * HZ);
  
  	mutex_unlock(&bch_register_lock);
  	return size;
  }
  
  static struct attribute *bch_cached_dev_files[] = {
  	&sysfs_attach,
  	&sysfs_detach,
  	&sysfs_stop,
  #if 0
  	&sysfs_data_csum,
  #endif
  	&sysfs_cache_mode,
  	&sysfs_writeback_metadata,
  	&sysfs_writeback_running,
  	&sysfs_writeback_delay,
  	&sysfs_writeback_percent,
  	&sysfs_writeback_rate,
  	&sysfs_writeback_rate_update_seconds,
  	&sysfs_writeback_rate_d_term,
  	&sysfs_writeback_rate_p_term_inverse,

  	&sysfs_writeback_rate_debug,
  	&sysfs_dirty_data,

  	&sysfs_stripe_size,
  	&sysfs_partial_stripes_expensive,

  	&sysfs_sequential_cutoff,

  	&sysfs_clear_stats,
  	&sysfs_running,
  	&sysfs_state,
  	&sysfs_label,
  	&sysfs_readahead,
  #ifdef CONFIG_BCACHE_DEBUG
  	&sysfs_verify,

  	&sysfs_bypass_torture_test,

  #endif
  	NULL
  };
  KTYPE(bch_cached_dev);
  
  SHOW(bch_flash_dev)
  {
  	struct bcache_device *d = container_of(kobj, struct bcache_device,
  					       kobj);
  	struct uuid_entry *u = &d->c->uuids[d->id];
  
  	sysfs_printf(data_csum,	"%i", d->data_csum);
  	sysfs_hprint(size,	u->sectors << 9);
  
  	if (attr == &sysfs_label) {
  		memcpy(buf, u->label, SB_LABEL_SIZE);
  		buf[SB_LABEL_SIZE + 1] = '\0';
  		strcat(buf, "
  ");
  		return strlen(buf);
  	}
  
  	return 0;
  }
  
  STORE(__bch_flash_dev)
  {
  	struct bcache_device *d = container_of(kobj, struct bcache_device,
  					       kobj);
  	struct uuid_entry *u = &d->c->uuids[d->id];
  
  	sysfs_strtoul(data_csum,	d->data_csum);
  
  	if (attr == &sysfs_size) {
  		uint64_t v;
  		strtoi_h_or_return(buf, v);
  
  		u->sectors = v >> 9;
  		bch_uuid_write(d->c);
  		set_capacity(d->disk, u->sectors);
  	}
  
  	if (attr == &sysfs_label) {
  		memcpy(u->label, buf, SB_LABEL_SIZE);
  		bch_uuid_write(d->c);
  	}
  
  	if (attr == &sysfs_unregister) {

  		set_bit(BCACHE_DEV_DETACHING, &d->flags);

  		bcache_device_stop(d);
  	}
  
  	return size;
  }
  STORE_LOCKED(bch_flash_dev)
  
  static struct attribute *bch_flash_dev_files[] = {
  	&sysfs_unregister,
  #if 0
  	&sysfs_data_csum,
  #endif
  	&sysfs_label,
  	&sysfs_size,
  	NULL
  };
  KTYPE(bch_flash_dev);

  struct bset_stats_op {
  	struct btree_op op;
  	size_t nodes;
  	struct bset_stats stats;
  };

  static int bch_btree_bset_stats(struct btree_op *b_op, struct btree *b)

  {
  	struct bset_stats_op *op = container_of(b_op, struct bset_stats_op, op);
  
  	op->nodes++;
  	bch_btree_keys_stats(&b->keys, &op->stats);
  
  	return MAP_CONTINUE;
  }

  static int bch_bset_print_stats(struct cache_set *c, char *buf)

  {
  	struct bset_stats_op op;
  	int ret;
  
  	memset(&op, 0, sizeof(op));
  	bch_btree_op_init(&op.op, -1);

  	ret = bch_btree_map_nodes(&op.op, c, &ZERO_KEY, bch_btree_bset_stats);

  	if (ret < 0)
  		return ret;
  
  	return snprintf(buf, PAGE_SIZE,
  			"btree nodes:		%zu
  "
  			"written sets:		%zu
  "
  			"unwritten sets:		%zu
  "
  			"written key bytes:	%zu
  "
  			"unwritten key bytes:	%zu
  "
  			"floats:			%zu
  "
  			"failed:			%zu
  ",
  			op.nodes,
  			op.stats.sets_written, op.stats.sets_unwritten,
  			op.stats.bytes_written, op.stats.bytes_unwritten,
  			op.stats.floats, op.stats.failed);
  }

  static unsigned bch_root_usage(struct cache_set *c)

  {

  	unsigned bytes = 0;
  	struct bkey *k;
  	struct btree *b;
  	struct btree_iter iter;

  	goto lock_root;

  	do {
  		rw_unlock(false, b);

  lock_root:

  		b = c->root;
  		rw_lock(false, b, b->level);
  	} while (b != c->root);

  	for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
  		bytes += bkey_bytes(k);

  	rw_unlock(false, b);

  	return (bytes * 100) / btree_bytes(c);
  }

  static size_t bch_cache_size(struct cache_set *c)
  {
  	size_t ret = 0;
  	struct btree *b;

  	mutex_lock(&c->bucket_lock);
  	list_for_each_entry(b, &c->btree_cache, list)
  		ret += 1 << (b->keys.page_order + PAGE_SHIFT);

  	mutex_unlock(&c->bucket_lock);
  	return ret;
  }

  static unsigned bch_cache_max_chain(struct cache_set *c)
  {
  	unsigned ret = 0;
  	struct hlist_head *h;

  	mutex_lock(&c->bucket_lock);

  	for (h = c->bucket_hash;
  	     h < c->bucket_hash + (1 << BUCKET_HASH_BITS);
  	     h++) {
  		unsigned i = 0;
  		struct hlist_node *p;

  		hlist_for_each(p, h)
  			i++;

  		ret = max(ret, i);

  	}

  	mutex_unlock(&c->bucket_lock);
  	return ret;
  }

  static unsigned bch_btree_used(struct cache_set *c)
  {
  	return div64_u64(c->gc_stats.key_bytes * 100,
  			 (c->gc_stats.nodes ?: 1) * btree_bytes(c));
  }

  static unsigned bch_average_key_size(struct cache_set *c)
  {
  	return c->gc_stats.nkeys
  		? div64_u64(c->gc_stats.data, c->gc_stats.nkeys)
  		: 0;
  }
  
  SHOW(__bch_cache_set)
  {

  	struct cache_set *c = container_of(kobj, struct cache_set, kobj);
  
  	sysfs_print(synchronous,		CACHE_SYNC(&c->sb));
  	sysfs_print(journal_delay_ms,		c->journal_delay_ms);
  	sysfs_hprint(bucket_size,		bucket_bytes(c));
  	sysfs_hprint(block_size,		block_bytes(c));
  	sysfs_print(tree_depth,			c->root->level);

  	sysfs_print(root_usage_percent,		bch_root_usage(c));

  	sysfs_hprint(btree_cache_size,		bch_cache_size(c));
  	sysfs_print(btree_cache_max_chain,	bch_cache_max_chain(c));

  	sysfs_print(cache_available_percent,	100 - c->gc_stats.in_use);
  
  	sysfs_print_time_stats(&c->btree_gc_time,	btree_gc, sec, ms);
  	sysfs_print_time_stats(&c->btree_split_time,	btree_split, sec, us);

  	sysfs_print_time_stats(&c->sort.time,		btree_sort, ms, us);

  	sysfs_print_time_stats(&c->btree_read_time,	btree_read, ms, us);

  	sysfs_print(btree_used_percent,	bch_btree_used(c));

  	sysfs_print(btree_nodes,	c->gc_stats.nodes);

  	sysfs_hprint(average_key_size,	bch_average_key_size(c));

  
  	sysfs_print(cache_read_races,
  		    atomic_long_read(&c->cache_read_races));
  
  	sysfs_print(writeback_keys_done,
  		    atomic_long_read(&c->writeback_keys_done));
  	sysfs_print(writeback_keys_failed,
  		    atomic_long_read(&c->writeback_keys_failed));

  	if (attr == &sysfs_errors)
  		return bch_snprint_string_list(buf, PAGE_SIZE, error_actions,
  					       c->on_error);

  	/* See count_io_errors for why 88 */
  	sysfs_print(io_error_halflife,	c->error_decay * 88);
  	sysfs_print(io_error_limit,	c->error_limit >> IO_ERROR_SHIFT);
  
  	sysfs_hprint(congested,
  		     ((uint64_t) bch_get_congested(c)) << 9);
  	sysfs_print(congested_read_threshold_us,
  		    c->congested_read_threshold_us);
  	sysfs_print(congested_write_threshold_us,
  		    c->congested_write_threshold_us);
  
  	sysfs_print(active_journal_entries,	fifo_used(&c->journal.pin));
  	sysfs_printf(verify,			"%i", c->verify);
  	sysfs_printf(key_merging_disabled,	"%i", c->key_merging_disabled);

  	sysfs_printf(expensive_debug_checks,
  		     "%i", c->expensive_debug_checks);

  	sysfs_printf(gc_always_rewrite,		"%i", c->gc_always_rewrite);
  	sysfs_printf(btree_shrinker_disabled,	"%i", c->shrinker_disabled);
  	sysfs_printf(copy_gc_enabled,		"%i", c->copy_gc_enabled);
  
  	if (attr == &sysfs_bset_tree_stats)
  		return bch_bset_print_stats(c, buf);
  
  	return 0;
  }
  SHOW_LOCKED(bch_cache_set)
  
  STORE(__bch_cache_set)
  {
  	struct cache_set *c = container_of(kobj, struct cache_set, kobj);
  
  	if (attr == &sysfs_unregister)
  		bch_cache_set_unregister(c);
  
  	if (attr == &sysfs_stop)
  		bch_cache_set_stop(c);
  
  	if (attr == &sysfs_synchronous) {
  		bool sync = strtoul_or_return(buf);
  
  		if (sync != CACHE_SYNC(&c->sb)) {
  			SET_CACHE_SYNC(&c->sb, sync);
  			bcache_write_super(c);
  		}
  	}
  
  	if (attr == &sysfs_flash_vol_create) {
  		int r;
  		uint64_t v;
  		strtoi_h_or_return(buf, v);
  
  		r = bch_flash_dev_create(c, v);
  		if (r)
  			return r;
  	}
  
  	if (attr == &sysfs_clear_stats) {
  		atomic_long_set(&c->writeback_keys_done,	0);
  		atomic_long_set(&c->writeback_keys_failed,	0);
  
  		memset(&c->gc_stats, 0, sizeof(struct gc_stat));
  		bch_cache_accounting_clear(&c->accounting);
  	}
  
  	if (attr == &sysfs_trigger_gc)

  		wake_up_gc(c);

  
  	if (attr == &sysfs_prune_cache) {
  		struct shrink_control sc;
  		sc.gfp_mask = GFP_KERNEL;
  		sc.nr_to_scan = strtoul_or_return(buf);

  		c->shrink.scan_objects(&c->shrink, &sc);

  	}
  
  	sysfs_strtoul(congested_read_threshold_us,
  		      c->congested_read_threshold_us);
  	sysfs_strtoul(congested_write_threshold_us,
  		      c->congested_write_threshold_us);

  	if (attr == &sysfs_errors) {
  		ssize_t v = bch_read_string_list(buf, error_actions);
  
  		if (v < 0)
  			return v;
  
  		c->on_error = v;
  	}

  	if (attr == &sysfs_io_error_limit)
  		c->error_limit = strtoul_or_return(buf) << IO_ERROR_SHIFT;
  
  	/* See count_io_errors() for why 88 */
  	if (attr == &sysfs_io_error_halflife)
  		c->error_decay = strtoul_or_return(buf) / 88;
  
  	sysfs_strtoul(journal_delay_ms,		c->journal_delay_ms);
  	sysfs_strtoul(verify,			c->verify);
  	sysfs_strtoul(key_merging_disabled,	c->key_merging_disabled);

  	sysfs_strtoul(expensive_debug_checks,	c->expensive_debug_checks);

  	sysfs_strtoul(gc_always_rewrite,	c->gc_always_rewrite);
  	sysfs_strtoul(btree_shrinker_disabled,	c->shrinker_disabled);
  	sysfs_strtoul(copy_gc_enabled,		c->copy_gc_enabled);
  
  	return size;
  }
  STORE_LOCKED(bch_cache_set)
  
  SHOW(bch_cache_set_internal)
  {
  	struct cache_set *c = container_of(kobj, struct cache_set, internal);
  	return bch_cache_set_show(&c->kobj, attr, buf);
  }
  
  STORE(bch_cache_set_internal)
  {
  	struct cache_set *c = container_of(kobj, struct cache_set, internal);
  	return bch_cache_set_store(&c->kobj, attr, buf, size);
  }
  
  static void bch_cache_set_internal_release(struct kobject *k)
  {
  }
  
  static struct attribute *bch_cache_set_files[] = {
  	&sysfs_unregister,
  	&sysfs_stop,
  	&sysfs_synchronous,
  	&sysfs_journal_delay_ms,
  	&sysfs_flash_vol_create,
  
  	&sysfs_bucket_size,
  	&sysfs_block_size,
  	&sysfs_tree_depth,
  	&sysfs_root_usage_percent,
  	&sysfs_btree_cache_size,
  	&sysfs_cache_available_percent,
  
  	&sysfs_average_key_size,

  	&sysfs_errors,

  	&sysfs_io_error_limit,
  	&sysfs_io_error_halflife,
  	&sysfs_congested,
  	&sysfs_congested_read_threshold_us,
  	&sysfs_congested_write_threshold_us,
  	&sysfs_clear_stats,
  	NULL
  };
  KTYPE(bch_cache_set);
  
  static struct attribute *bch_cache_set_internal_files[] = {
  	&sysfs_active_journal_entries,
  
  	sysfs_time_stats_attribute_list(btree_gc, sec, ms)
  	sysfs_time_stats_attribute_list(btree_split, sec, us)
  	sysfs_time_stats_attribute_list(btree_sort, ms, us)
  	sysfs_time_stats_attribute_list(btree_read, ms, us)

  
  	&sysfs_btree_nodes,
  	&sysfs_btree_used_percent,
  	&sysfs_btree_cache_max_chain,
  
  	&sysfs_bset_tree_stats,
  	&sysfs_cache_read_races,
  	&sysfs_writeback_keys_done,
  	&sysfs_writeback_keys_failed,
  
  	&sysfs_trigger_gc,
  	&sysfs_prune_cache,
  #ifdef CONFIG_BCACHE_DEBUG
  	&sysfs_verify,
  	&sysfs_key_merging_disabled,

  	&sysfs_expensive_debug_checks,

  #endif
  	&sysfs_gc_always_rewrite,
  	&sysfs_btree_shrinker_disabled,
  	&sysfs_copy_gc_enabled,
  	NULL
  };
  KTYPE(bch_cache_set_internal);
  
  SHOW(__bch_cache)
  {
  	struct cache *ca = container_of(kobj, struct cache, kobj);
  
  	sysfs_hprint(bucket_size,	bucket_bytes(ca));
  	sysfs_hprint(block_size,	block_bytes(ca));
  	sysfs_print(nbuckets,		ca->sb.nbuckets);
  	sysfs_print(discard,		ca->discard);
  	sysfs_hprint(written, atomic_long_read(&ca->sectors_written) << 9);
  	sysfs_hprint(btree_written,
  		     atomic_long_read(&ca->btree_sectors_written) << 9);
  	sysfs_hprint(metadata_written,
  		     (atomic_long_read(&ca->meta_sectors_written) +
  		      atomic_long_read(&ca->btree_sectors_written)) << 9);
  
  	sysfs_print(io_errors,
  		    atomic_read(&ca->io_errors) >> IO_ERROR_SHIFT);

  	if (attr == &sysfs_cache_replacement_policy)

  		return bch_snprint_string_list(buf, PAGE_SIZE,
  					       cache_replacement_policies,
  					       CACHE_REPLACEMENT(&ca->sb));

  
  	if (attr == &sysfs_priority_stats) {
  		int cmp(const void *l, const void *r)
  		{	return *((uint16_t *) r) - *((uint16_t *) l); }

  		struct bucket *b;
  		size_t n = ca->sb.nbuckets, i;
  		size_t unused = 0, available = 0, dirty = 0, meta = 0;

  		uint64_t sum = 0;

  		/* Compute 31 quantiles */
  		uint16_t q[31], *p, *cached;

  		ssize_t ret;
  
  		cached = p = vmalloc(ca->sb.nbuckets * sizeof(uint16_t));
  		if (!p)
  			return -ENOMEM;
  
  		mutex_lock(&ca->set->bucket_lock);

  		for_each_bucket(b, ca) {
  			if (!GC_SECTORS_USED(b))
  				unused++;
  			if (GC_MARK(b) == GC_MARK_RECLAIMABLE)
  				available++;
  			if (GC_MARK(b) == GC_MARK_DIRTY)
  				dirty++;
  			if (GC_MARK(b) == GC_MARK_METADATA)
  				meta++;
  		}

  		for (i = ca->sb.first_bucket; i < n; i++)
  			p[i] = ca->buckets[i].prio;
  		mutex_unlock(&ca->set->bucket_lock);
  
  		sort(p, n, sizeof(uint16_t), cmp, NULL);
  
  		while (n &&
  		       !cached[n - 1])
  			--n;
  
  		unused = ca->sb.nbuckets - n;
  
  		while (cached < p + n &&
  		       *cached == BTREE_PRIO)

  			cached++, n--;

  
  		for (i = 0; i < n; i++)
  			sum += INITIAL_PRIO - cached[i];
  
  		if (n)
  			do_div(sum, n);

  		for (i = 0; i < ARRAY_SIZE(q); i++)
  			q[i] = INITIAL_PRIO - cached[n * (i + 1) /
  				(ARRAY_SIZE(q) + 1)];

  
  		vfree(p);

  		ret = scnprintf(buf, PAGE_SIZE,
  				"Unused:		%zu%%
  "

  				"Clean:		%zu%%
  "
  				"Dirty:		%zu%%
  "

  				"Metadata:	%zu%%
  "
  				"Average:	%llu
  "
  				"Sectors per Q:	%zu
  "
  				"Quantiles:	[",
  				unused * 100 / (size_t) ca->sb.nbuckets,

  				available * 100 / (size_t) ca->sb.nbuckets,
  				dirty * 100 / (size_t) ca->sb.nbuckets,
  				meta * 100 / (size_t) ca->sb.nbuckets, sum,

  				n * ca->sb.bucket_size / (ARRAY_SIZE(q) + 1));
  
  		for (i = 0; i < ARRAY_SIZE(q); i++)
  			ret += scnprintf(buf + ret, PAGE_SIZE - ret,
  					 "%u ", q[i]);
  		ret--;
  
  		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "]
  ");

  		return ret;
  	}
  
  	return 0;
  }
  SHOW_LOCKED(bch_cache)
  
  STORE(__bch_cache)
  {
  	struct cache *ca = container_of(kobj, struct cache, kobj);
  
  	if (attr == &sysfs_discard) {
  		bool v = strtoul_or_return(buf);
  
  		if (blk_queue_discard(bdev_get_queue(ca->bdev)))
  			ca->discard = v;
  
  		if (v != CACHE_DISCARD(&ca->sb)) {
  			SET_CACHE_DISCARD(&ca->sb, v);
  			bcache_write_super(ca->set);
  		}
  	}
  
  	if (attr == &sysfs_cache_replacement_policy) {

  		ssize_t v = bch_read_string_list(buf, cache_replacement_policies);

  
  		if (v < 0)
  			return v;
  
  		if ((unsigned) v != CACHE_REPLACEMENT(&ca->sb)) {
  			mutex_lock(&ca->set->bucket_lock);
  			SET_CACHE_REPLACEMENT(&ca->sb, v);
  			mutex_unlock(&ca->set->bucket_lock);
  
  			bcache_write_super(ca->set);
  		}
  	}

  	if (attr == &sysfs_clear_stats) {
  		atomic_long_set(&ca->sectors_written, 0);
  		atomic_long_set(&ca->btree_sectors_written, 0);
  		atomic_long_set(&ca->meta_sectors_written, 0);
  		atomic_set(&ca->io_count, 0);
  		atomic_set(&ca->io_errors, 0);
  	}
  
  	return size;
  }
  STORE_LOCKED(bch_cache)
  
  static struct attribute *bch_cache_files[] = {
  	&sysfs_bucket_size,
  	&sysfs_block_size,
  	&sysfs_nbuckets,
  	&sysfs_priority_stats,
  	&sysfs_discard,
  	&sysfs_written,
  	&sysfs_btree_written,
  	&sysfs_metadata_written,
  	&sysfs_io_errors,
  	&sysfs_clear_stats,

  	&sysfs_cache_replacement_policy,
  	NULL
  };
  KTYPE(bch_cache);