Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1183 insertions, 0 deletions

diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
new file mode 100644
index 000000000..cfac56caa
--- /dev/null
+++ b/drivers/md/bcache/sysfs.c
@@ -0,0 +1,1183 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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 "features.h"
+
+#include <linux/blkdev.h>
+#include <linux/sort.h>
+#include <linux/sched/clock.h>
+
+extern bool bcache_is_reboot;
+
+/* Default is 0 ("writethrough") */
+static const char * const bch_cache_modes[] = {
+	"writethrough",
+	"writeback",
+	"writearound",
+	"none",
+	NULL
+};
+
+static const char * const bch_reada_cache_policies[] = {
+	"all",
+	"meta-only",
+	NULL
+};
+
+/* Default is 0 ("auto") */
+static const char * const bch_stop_on_failure_modes[] = {
+	"auto",
+	"always",
+	NULL
+};
+
+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);
+read_attribute(backing_dev_name);
+read_attribute(backing_dev_uuid);
+
+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(feature_compat);
+read_attribute(feature_ro_compat);
+read_attribute(feature_incompat);
+
+read_attribute(state);
+read_attribute(cache_read_races);
+read_attribute(reclaim);
+read_attribute(reclaimed_journal_buckets);
+read_attribute(flush_write);
+read_attribute(writeback_keys_done);
+read_attribute(writeback_keys_failed);
+read_attribute(io_errors);
+read_attribute(congested);
+read_attribute(cutoff_writeback);
+read_attribute(cutoff_writeback_sync);
+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(readahead_cache_policy);
+rw_attribute(stop_when_cache_set_failed);
+rw_attribute(writeback_metadata);
+rw_attribute(writeback_running);
+rw_attribute(writeback_percent);
+rw_attribute(writeback_delay);
+rw_attribute(writeback_rate);
+rw_attribute(writeback_consider_fragment);
+
+rw_attribute(writeback_rate_update_seconds);
+rw_attribute(writeback_rate_i_term_inverse);
+rw_attribute(writeback_rate_p_term_inverse);
+rw_attribute(writeback_rate_fp_term_low);
+rw_attribute(writeback_rate_fp_term_mid);
+rw_attribute(writeback_rate_fp_term_high);
+rw_attribute(writeback_rate_minimum);
+read_attribute(writeback_rate_debug);
+
+read_attribute(stripe_size);
+read_attribute(partial_stripes_expensive);
+
+rw_attribute(synchronous);
+rw_attribute(journal_delay_ms);
+rw_attribute(io_disable);
+rw_attribute(running);
+rw_attribute(label);
+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(idle_max_writeback_rate);
+rw_attribute(gc_after_writeback);
+rw_attribute(size);
+
+static ssize_t bch_snprint_string_list(char *buf,
+				       size_t size,
+				       const char * const list[],
+				       size_t selected)
+{
+	char *out = buf;
+	size_t i;
+
+	for (i = 0; list[i]; i++)
+		out += scnprintf(out, buf + size - out,
+				i == selected ? "[%s] " : "%s ", list[i]);
+
+	out[-1] = '\n';
+	return out - buf;
+}
+
+SHOW(__bch_cached_dev)
+{
+	struct cached_dev *dc = container_of(kobj, struct cached_dev,
+					     disk.kobj);
+	char const *states[] = { "no cache", "clean", "dirty", "inconsistent" };
+	int wb = dc->writeback_running;
+
+#define var(stat)		(dc->stat)
+
+	if (attr == &sysfs_cache_mode)
+		return bch_snprint_string_list(buf, PAGE_SIZE,
+					       bch_cache_modes,
+					       BDEV_CACHE_MODE(&dc->sb));
+
+	if (attr == &sysfs_readahead_cache_policy)
+		return bch_snprint_string_list(buf, PAGE_SIZE,
+					      bch_reada_cache_policies,
+					      dc->cache_readahead_policy);
+
+	if (attr == &sysfs_stop_when_cache_set_failed)
+		return bch_snprint_string_list(buf, PAGE_SIZE,
+					       bch_stop_on_failure_modes,
+					       dc->stop_when_cache_set_failed);
+
+
+	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_printf(writeback_consider_fragment,	"%i");
+	var_print(writeback_delay);
+	var_print(writeback_percent);
+	sysfs_hprint(writeback_rate,
+		     wb ? atomic_long_read(&dc->writeback_rate.rate) << 9 : 0);
+	sysfs_printf(io_errors,		"%i", atomic_read(&dc->io_errors));
+	sysfs_printf(io_error_limit,	"%i", dc->error_limit);
+	sysfs_printf(io_disable,	"%i", dc->io_disable);
+	var_print(writeback_rate_update_seconds);
+	var_print(writeback_rate_i_term_inverse);
+	var_print(writeback_rate_p_term_inverse);
+	var_print(writeback_rate_fp_term_low);
+	var_print(writeback_rate_fp_term_mid);
+	var_print(writeback_rate_fp_term_high);
+	var_print(writeback_rate_minimum);
+
+	if (attr == &sysfs_writeback_rate_debug) {
+		char rate[20];
+		char dirty[20];
+		char target[20];
+		char proportional[20];
+		char integral[20];
+		char change[20];
+		s64 next_io;
+
+		/*
+		 * Except for dirty and target, other values should
+		 * be 0 if writeback is not running.
+		 */
+		bch_hprint(rate,
+			   wb ? atomic_long_read(&dc->writeback_rate.rate) << 9
+			      : 0);
+		bch_hprint(dirty, bcache_dev_sectors_dirty(&dc->disk) << 9);
+		bch_hprint(target, dc->writeback_rate_target << 9);
+		bch_hprint(proportional,
+			   wb ? dc->writeback_rate_proportional << 9 : 0);
+		bch_hprint(integral,
+			   wb ? dc->writeback_rate_integral_scaled << 9 : 0);
+		bch_hprint(change, wb ? dc->writeback_rate_change << 9 : 0);
+		next_io = wb ? div64_s64(dc->writeback_rate.next-local_clock(),
+					 NSEC_PER_MSEC) : 0;
+
+		return sprintf(buf,
+			       "rate:\t\t%s/sec\n"
+			       "dirty:\t\t%s\n"
+			       "target:\t\t%s\n"
+			       "proportional:\t%s\n"
+			       "integral:\t%s\n"
+			       "change:\t\t%s/sec\n"
+			       "next io:\t%llims\n",
+			       rate, dirty, target, proportional,
+			       integral, change, next_io);
+	}
+
+	sysfs_hprint(dirty_data,
+		     bcache_dev_sectors_dirty(&dc->disk) << 9);
+
+	sysfs_hprint(stripe_size,	 ((uint64_t)dc->disk.stripe_size) << 9);
+	var_printf(partial_stripes_expensive,	"%u");
+
+	var_hprint(sequential_cutoff);
+
+	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, "\n");
+		return strlen(buf);
+	}
+
+	if (attr == &sysfs_backing_dev_name) {
+		snprintf(buf, BDEVNAME_SIZE + 1, "%pg", dc->bdev);
+		strcat(buf, "\n");
+		return strlen(buf);
+	}
+
+	if (attr == &sysfs_backing_dev_uuid) {
+		/* convert binary uuid into 36-byte string plus '\0' */
+		snprintf(buf, 36+1, "%pU", dc->sb.uuid);
+		strcat(buf, "\n");
+		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);
+	ssize_t v;
+	struct cache_set *c;
+	struct kobj_uevent_env *env;
+
+	/* no user space access if system is rebooting */
+	if (bcache_is_reboot)
+		return -EBUSY;
+
+#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);
+	sysfs_strtoul_bool(bypass_torture_test, dc->bypass_torture_test);
+	sysfs_strtoul_bool(writeback_metadata, dc->writeback_metadata);
+	sysfs_strtoul_bool(writeback_running, dc->writeback_running);
+	sysfs_strtoul_bool(writeback_consider_fragment, dc->writeback_consider_fragment);
+	sysfs_strtoul_clamp(writeback_delay, dc->writeback_delay, 0, UINT_MAX);
+
+	sysfs_strtoul_clamp(writeback_percent, dc->writeback_percent,
+			    0, bch_cutoff_writeback);
+
+	if (attr == &sysfs_writeback_rate) {
+		ssize_t ret;
+		long int v = atomic_long_read(&dc->writeback_rate.rate);
+
+		ret = strtoul_safe_clamp(buf, v, 1, INT_MAX);
+
+		if (!ret) {
+			atomic_long_set(&dc->writeback_rate.rate, v);
+			ret = size;
+		}
+
+		return ret;
+	}
+
+	sysfs_strtoul_clamp(writeback_rate_update_seconds,
+			    dc->writeback_rate_update_seconds,
+			    1, WRITEBACK_RATE_UPDATE_SECS_MAX);
+	sysfs_strtoul_clamp(writeback_rate_i_term_inverse,
+			    dc->writeback_rate_i_term_inverse,
+			    1, UINT_MAX);
+	sysfs_strtoul_clamp(writeback_rate_p_term_inverse,
+			    dc->writeback_rate_p_term_inverse,
+			    1, UINT_MAX);
+	sysfs_strtoul_clamp(writeback_rate_fp_term_low,
+			    dc->writeback_rate_fp_term_low,
+			    1, dc->writeback_rate_fp_term_mid - 1);
+	sysfs_strtoul_clamp(writeback_rate_fp_term_mid,
+			    dc->writeback_rate_fp_term_mid,
+			    dc->writeback_rate_fp_term_low + 1,
+			    dc->writeback_rate_fp_term_high - 1);
+	sysfs_strtoul_clamp(writeback_rate_fp_term_high,
+			    dc->writeback_rate_fp_term_high,
+			    dc->writeback_rate_fp_term_mid + 1, UINT_MAX);
+	sysfs_strtoul_clamp(writeback_rate_minimum,
+			    dc->writeback_rate_minimum,
+			    1, UINT_MAX);
+
+	sysfs_strtoul_clamp(io_error_limit, dc->error_limit, 0, INT_MAX);
+
+	if (attr == &sysfs_io_disable) {
+		int v = strtoul_or_return(buf);
+
+		dc->io_disable = v ? 1 : 0;
+	}
+
+	sysfs_strtoul_clamp(sequential_cutoff,
+			    dc->sequential_cutoff,
+			    0, UINT_MAX);
+
+	if (attr == &sysfs_clear_stats)
+		bch_cache_accounting_clear(&dc->accounting);
+
+	if (attr == &sysfs_running &&
+	    strtoul_or_return(buf)) {
+		v = bch_cached_dev_run(dc);
+		if (v)
+			return v;
+	}
+
+	if (attr == &sysfs_cache_mode) {
+		v = __sysfs_match_string(bch_cache_modes, -1, buf);
+		if (v < 0)
+			return v;
+
+		if ((unsigned int) v != BDEV_CACHE_MODE(&dc->sb)) {
+			SET_BDEV_CACHE_MODE(&dc->sb, v);
+			bch_write_bdev_super(dc, NULL);
+		}
+	}
+
+	if (attr == &sysfs_readahead_cache_policy) {
+		v = __sysfs_match_string(bch_reada_cache_policies, -1, buf);
+		if (v < 0)
+			return v;
+
+		if ((unsigned int) v != dc->cache_readahead_policy)
+			dc->cache_readahead_policy = v;
+	}
+
+	if (attr == &sysfs_stop_when_cache_set_failed) {
+		v = __sysfs_match_string(bch_stop_on_failure_modes, -1, buf);
+		if (v < 0)
+			return v;
+
+		dc->stop_when_cache_set_failed = v;
+	}
+
+	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] == '\n')
+			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_obj(struct kobj_uevent_env);
+		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) {
+		uint8_t		set_uuid[16];
+
+		if (bch_parse_uuid(buf, set_uuid) < 16)
+			return -EINVAL;
+
+		v = -ENOENT;
+		list_for_each_entry(c, &bch_cache_sets, list) {
+			v = bch_cached_dev_attach(dc, c, set_uuid);
+			if (!v)
+				return size;
+		}
+		if (v == -ENOENT)
+			pr_err("Can't attach %s: cache set not found\n", buf);
+		return 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);
+
+	/* no user space access if system is rebooting */
+	if (bcache_is_reboot)
+		return -EBUSY;
+
+	mutex_lock(&bch_register_lock);
+	size = __cached_dev_store(kobj, attr, buf, size);
+
+	if (attr == &sysfs_writeback_running) {
+		/* dc->writeback_running changed in __cached_dev_store() */
+		if (IS_ERR_OR_NULL(dc->writeback_thread)) {
+			/*
+			 * reject setting it to 1 via sysfs if writeback
+			 * kthread is not created yet.
+			 */
+			if (dc->writeback_running) {
+				dc->writeback_running = false;
+				pr_err("%s: failed to run non-existent writeback thread\n",
+						dc->disk.disk->disk_name);
+			}
+		} else
+			/*
+			 * writeback kthread will check if dc->writeback_running
+			 * is true or false.
+			 */
+			bch_writeback_queue(dc);
+	}
+
+	/*
+	 * Only set BCACHE_DEV_WB_RUNNING when cached device attached to
+	 * a cache set, otherwise it doesn't make sense.
+	 */
+	if (attr == &sysfs_writeback_percent)
+		if ((dc->disk.c != NULL) &&
+		    (!test_and_set_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)))
+			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_attrs[] = {
+	&sysfs_attach,
+	&sysfs_detach,
+	&sysfs_stop,
+#if 0
+	&sysfs_data_csum,
+#endif
+	&sysfs_cache_mode,
+	&sysfs_readahead_cache_policy,
+	&sysfs_stop_when_cache_set_failed,
+	&sysfs_writeback_metadata,
+	&sysfs_writeback_running,
+	&sysfs_writeback_delay,
+	&sysfs_writeback_percent,
+	&sysfs_writeback_rate,
+	&sysfs_writeback_consider_fragment,
+	&sysfs_writeback_rate_update_seconds,
+	&sysfs_writeback_rate_i_term_inverse,
+	&sysfs_writeback_rate_p_term_inverse,
+	&sysfs_writeback_rate_fp_term_low,
+	&sysfs_writeback_rate_fp_term_mid,
+	&sysfs_writeback_rate_fp_term_high,
+	&sysfs_writeback_rate_minimum,
+	&sysfs_writeback_rate_debug,
+	&sysfs_io_errors,
+	&sysfs_io_error_limit,
+	&sysfs_io_disable,
+	&sysfs_dirty_data,
+	&sysfs_stripe_size,
+	&sysfs_partial_stripes_expensive,
+	&sysfs_sequential_cutoff,
+	&sysfs_clear_stats,
+	&sysfs_running,
+	&sysfs_state,
+	&sysfs_label,
+#ifdef CONFIG_BCACHE_DEBUG
+	&sysfs_verify,
+	&sysfs_bypass_torture_test,
+#endif
+	&sysfs_backing_dev_name,
+	&sysfs_backing_dev_uuid,
+	NULL
+};
+ATTRIBUTE_GROUPS(bch_cached_dev);
+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, "\n");
+		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];
+
+	/* no user space access if system is rebooting */
+	if (bcache_is_reboot)
+		return -EBUSY;
+
+	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_attrs[] = {
+	&sysfs_unregister,
+#if 0
+	&sysfs_data_csum,
+#endif
+	&sysfs_label,
+	&sysfs_size,
+	NULL
+};
+ATTRIBUTE_GROUPS(bch_flash_dev);
+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\n"
+			"written sets:		%zu\n"
+			"unwritten sets:		%zu\n"
+			"written key bytes:	%zu\n"
+			"unwritten key bytes:	%zu\n"
+			"floats:			%zu\n"
+			"failed:			%zu\n",
+			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 int bch_root_usage(struct cache_set *c)
+{
+	unsigned int bytes = 0;
+	struct bkey *k;
+	struct btree *b;
+	struct btree_iter_stack 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 int bch_cache_max_chain(struct cache_set *c)
+{
+	unsigned int 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++) {
+		ret = max(ret, hlist_count_nodes(h));
+	}
+
+	mutex_unlock(&c->bucket_lock);
+	return ret;
+}
+
+static unsigned int 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 int 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->cache->sb));
+	sysfs_print(journal_delay_ms,		c->journal_delay_ms);
+	sysfs_hprint(bucket_size,		bucket_bytes(c->cache));
+	sysfs_hprint(block_size,		block_bytes(c->cache));
+	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(reclaim,
+		    atomic_long_read(&c->reclaim));
+
+	sysfs_print(reclaimed_journal_buckets,
+		    atomic_long_read(&c->reclaimed_journal_buckets));
+
+	sysfs_print(flush_write,
+		    atomic_long_read(&c->flush_write));
+
+	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);
+
+	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(cutoff_writeback, bch_cutoff_writeback);
+	sysfs_print(cutoff_writeback_sync, bch_cutoff_writeback_sync);
+
+	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);
+	sysfs_printf(idle_max_writeback_rate,	"%i",
+		     c->idle_max_writeback_rate_enabled);
+	sysfs_printf(gc_after_writeback,	"%i", c->gc_after_writeback);
+	sysfs_printf(io_disable,		"%i",
+		     test_bit(CACHE_SET_IO_DISABLE, &c->flags));
+
+	if (attr == &sysfs_bset_tree_stats)
+		return bch_bset_print_stats(c, buf);
+
+	if (attr == &sysfs_feature_compat)
+		return bch_print_cache_set_feature_compat(c, buf, PAGE_SIZE);
+	if (attr == &sysfs_feature_ro_compat)
+		return bch_print_cache_set_feature_ro_compat(c, buf, PAGE_SIZE);
+	if (attr == &sysfs_feature_incompat)
+		return bch_print_cache_set_feature_incompat(c, buf, PAGE_SIZE);
+
+	return 0;
+}
+SHOW_LOCKED(bch_cache_set)
+
+STORE(__bch_cache_set)
+{
+	struct cache_set *c = container_of(kobj, struct cache_set, kobj);
+	ssize_t v;
+
+	/* no user space access if system is rebooting */
+	if (bcache_is_reboot)
+		return -EBUSY;
+
+	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->cache->sb)) {
+			SET_CACHE_SYNC(&c->cache->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)
+		force_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);
+		if (c->shrink)
+			c->shrink->scan_objects(c->shrink, &sc);
+	}
+
+	sysfs_strtoul_clamp(congested_read_threshold_us,
+			    c->congested_read_threshold_us,
+			    0, UINT_MAX);
+	sysfs_strtoul_clamp(congested_write_threshold_us,
+			    c->congested_write_threshold_us,
+			    0, UINT_MAX);
+
+	if (attr == &sysfs_errors) {
+		v = __sysfs_match_string(error_actions, -1, buf);
+		if (v < 0)
+			return v;
+
+		c->on_error = v;
+	}
+
+	sysfs_strtoul_clamp(io_error_limit, c->error_limit, 0, UINT_MAX);
+
+	/* See count_io_errors() for why 88 */
+	if (attr == &sysfs_io_error_halflife) {
+		unsigned long v = 0;
+		ssize_t ret;
+
+		ret = strtoul_safe_clamp(buf, v, 0, UINT_MAX);
+		if (!ret) {
+			c->error_decay = v / 88;
+			return size;
+		}
+		return ret;
+	}
+
+	if (attr == &sysfs_io_disable) {
+		v = strtoul_or_return(buf);
+		if (v) {
+			if (test_and_set_bit(CACHE_SET_IO_DISABLE,
+					     &c->flags))
+				pr_warn("CACHE_SET_IO_DISABLE already set\n");
+		} else {
+			if (!test_and_clear_bit(CACHE_SET_IO_DISABLE,
+						&c->flags))
+				pr_warn("CACHE_SET_IO_DISABLE already cleared\n");
+		}
+	}
+
+	sysfs_strtoul_clamp(journal_delay_ms,
+			    c->journal_delay_ms,
+			    0, USHRT_MAX);
+	sysfs_strtoul_bool(verify,		c->verify);
+	sysfs_strtoul_bool(key_merging_disabled, c->key_merging_disabled);
+	sysfs_strtoul(expensive_debug_checks,	c->expensive_debug_checks);
+	sysfs_strtoul_bool(gc_always_rewrite,	c->gc_always_rewrite);
+	sysfs_strtoul_bool(btree_shrinker_disabled, c->shrinker_disabled);
+	sysfs_strtoul_bool(copy_gc_enabled,	c->copy_gc_enabled);
+	sysfs_strtoul_bool(idle_max_writeback_rate,
+			   c->idle_max_writeback_rate_enabled);
+
+	/*
+	 * write gc_after_writeback here may overwrite an already set
+	 * BCH_DO_AUTO_GC, it doesn't matter because this flag will be
+	 * set in next chance.
+	 */
+	sysfs_strtoul_clamp(gc_after_writeback, c->gc_after_writeback, 0, 1);
+
+	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);
+
+	/* no user space access if system is rebooting */
+	if (bcache_is_reboot)
+		return -EBUSY;
+
+	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_attrs[] = {
+	&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
+};
+ATTRIBUTE_GROUPS(bch_cache_set);
+KTYPE(bch_cache_set);
+
+static struct attribute *bch_cache_set_internal_attrs[] = {
+	&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_reclaim,
+	&sysfs_reclaimed_journal_buckets,
+	&sysfs_flush_write,
+	&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,
+	&sysfs_idle_max_writeback_rate,
+	&sysfs_gc_after_writeback,
+	&sysfs_io_disable,
+	&sysfs_cutoff_writeback,
+	&sysfs_cutoff_writeback_sync,
+	&sysfs_feature_compat,
+	&sysfs_feature_ro_compat,
+	&sysfs_feature_incompat,
+	NULL
+};
+ATTRIBUTE_GROUPS(bch_cache_set_internal);
+KTYPE(bch_cache_set_internal);
+
+static int __bch_cache_cmp(const void *l, const void *r)
+{
+	cond_resched();
+	return *((uint16_t *)r) - *((uint16_t *)l);
+}
+
+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_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) {
+		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(array_size(sizeof(uint16_t),
+						ca->sb.nbuckets));
+		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), __bch_cache_cmp, NULL);
+
+		while (n &&
+		       !cached[n - 1])
+			--n;
+
+		while (cached < p + n &&
+		       *cached == BTREE_PRIO) {
+			cached++;
+			n--;
+		}
+
+		for (i = 0; i < n; i++)
+			sum += INITIAL_PRIO - cached[i];
+
+		if (n)
+			sum = div64_u64(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 = sysfs_emit(buf,
+				 "Unused:		%zu%%\n"
+				 "Clean:		%zu%%\n"
+				 "Dirty:		%zu%%\n"
+				 "Metadata:	%zu%%\n"
+				 "Average:	%llu\n"
+				 "Sectors per Q:	%zu\n"
+				 "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 += sysfs_emit_at(buf, ret, "%u ", q[i]);
+		ret--;
+
+		ret += sysfs_emit_at(buf, ret, "]\n");
+
+		return ret;
+	}
+
+	return 0;
+}
+SHOW_LOCKED(bch_cache)
+
+STORE(__bch_cache)
+{
+	struct cache *ca = container_of(kobj, struct cache, kobj);
+	ssize_t v;
+
+	/* no user space access if system is rebooting */
+	if (bcache_is_reboot)
+		return -EBUSY;
+
+	if (attr == &sysfs_cache_replacement_policy) {
+		v = __sysfs_match_string(cache_replacement_policies, -1, buf);
+		if (v < 0)
+			return v;
+
+		if ((unsigned int) 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_attrs[] = {
+	&sysfs_bucket_size,
+	&sysfs_block_size,
+	&sysfs_nbuckets,
+	&sysfs_priority_stats,
+	&sysfs_written,
+	&sysfs_btree_written,
+	&sysfs_metadata_written,
+	&sysfs_io_errors,
+	&sysfs_clear_stats,
+	&sysfs_cache_replacement_policy,
+	NULL
+};
+ATTRIBUTE_GROUPS(bch_cache);
+KTYPE(bch_cache);