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-rw-r--r--libbcachefs/sysfs.c147
1 files changed, 123 insertions, 24 deletions
diff --git a/libbcachefs/sysfs.c b/libbcachefs/sysfs.c
index e5f003c2..455c6ae9 100644
--- a/libbcachefs/sysfs.c
+++ b/libbcachefs/sysfs.c
@@ -40,6 +40,7 @@
#include <linux/blkdev.h>
#include <linux/sort.h>
+#include <linux/string_choices.h>
#include <linux/sched/clock.h>
#include "util.h"
@@ -148,6 +149,7 @@ write_attribute(trigger_btree_key_cache_shrink);
write_attribute(trigger_freelist_wakeup);
write_attribute(trigger_btree_updates);
read_attribute(gc_gens_pos);
+__sysfs_attribute(read_fua_test, 0400);
read_attribute(uuid);
read_attribute(minor);
@@ -308,6 +310,116 @@ static void bch2_fs_usage_base_to_text(struct printbuf *out, struct bch_fs *c)
prt_printf(out, "nr_inodes:\t%llu\n", b.nr_inodes);
}
+static int bch2_read_fua_test(struct printbuf *out, struct bch_dev *ca)
+{
+ struct bch_fs *c = ca->fs;
+ struct bio *bio = NULL;
+ void *buf = NULL;
+ unsigned bs = c->opts.block_size, iters;
+ u64 end, test_duration = NSEC_PER_SEC * 2;
+ struct bch2_time_stats stats_nofua, stats_fua, stats_random;
+ int ret = 0;
+
+ bch2_time_stats_init_no_pcpu(&stats_nofua);
+ bch2_time_stats_init_no_pcpu(&stats_fua);
+ bch2_time_stats_init_no_pcpu(&stats_random);
+
+ if (!bch2_dev_get_ioref(c, ca->dev_idx, READ)) {
+ prt_str(out, "offline\n");
+ return 0;
+ }
+
+ struct block_device *bdev = ca->disk_sb.bdev;
+
+ bio = bio_kmalloc(1, GFP_KERNEL);
+ if (!bio) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ buf = kmalloc(bs, GFP_KERNEL);
+ if (!buf)
+ goto err;
+
+ end = ktime_get_ns() + test_duration;
+ for (iters = 0; iters < 1000 && time_before64(ktime_get_ns(), end); iters++) {
+ bio_init(bio, bdev, bio->bi_inline_vecs, 1, READ);
+ bch2_bio_map(bio, buf, bs);
+
+ u64 submit_time = ktime_get_ns();
+ ret = submit_bio_wait(bio);
+ bch2_time_stats_update(&stats_nofua, submit_time);
+
+ if (ret)
+ goto err;
+ }
+
+ end = ktime_get_ns() + test_duration;
+ for (iters = 0; iters < 1000 && time_before64(ktime_get_ns(), end); iters++) {
+ bio_init(bio, bdev, bio->bi_inline_vecs, 1, REQ_FUA|READ);
+ bch2_bio_map(bio, buf, bs);
+
+ u64 submit_time = ktime_get_ns();
+ ret = submit_bio_wait(bio);
+ bch2_time_stats_update(&stats_fua, submit_time);
+
+ if (ret)
+ goto err;
+ }
+
+ u64 dev_size = ca->mi.nbuckets * bucket_bytes(ca);
+
+ end = ktime_get_ns() + test_duration;
+ for (iters = 0; iters < 1000 && time_before64(ktime_get_ns(), end); iters++) {
+ bio_init(bio, bdev, bio->bi_inline_vecs, 1, READ);
+ bio->bi_iter.bi_sector = (bch2_get_random_u64_below(dev_size) & ~((u64) bs - 1)) >> 9;
+ bch2_bio_map(bio, buf, bs);
+
+ u64 submit_time = ktime_get_ns();
+ ret = submit_bio_wait(bio);
+ bch2_time_stats_update(&stats_random, submit_time);
+
+ if (ret)
+ goto err;
+ }
+
+ u64 ns_nofua = mean_and_variance_get_mean(stats_nofua.duration_stats);
+ u64 ns_fua = mean_and_variance_get_mean(stats_fua.duration_stats);
+ u64 ns_rand = mean_and_variance_get_mean(stats_random.duration_stats);
+
+ u64 stddev_nofua = mean_and_variance_get_stddev(stats_nofua.duration_stats);
+ u64 stddev_fua = mean_and_variance_get_stddev(stats_fua.duration_stats);
+ u64 stddev_rand = mean_and_variance_get_stddev(stats_random.duration_stats);
+
+ printbuf_tabstop_push(out, 8);
+ printbuf_tabstop_push(out, 12);
+ printbuf_tabstop_push(out, 12);
+ prt_printf(out, "This test must be run on an idle drive for accurate results\n");
+ prt_printf(out, "%s\n", dev_name(&ca->disk_sb.bdev->bd_device));
+ prt_printf(out, "fua support advertized: %s\n", str_yes_no(bdev_fua(bdev)));
+ prt_newline(out);
+ prt_printf(out, "ns:\tlatency\rstddev\r\n");
+ prt_printf(out, "nofua\t%llu\r%llu\r\n", ns_nofua, stddev_nofua);
+ prt_printf(out, "fua\t%llu\r%llu\r\n", ns_fua, stddev_fua);
+ prt_printf(out, "random\t%llu\r%llu\r\n", ns_rand, stddev_rand);
+
+ bool read_cache = ns_nofua * 2 < ns_rand;
+ bool fua_cached = read_cache && ns_fua < (ns_nofua + ns_rand) / 2;
+
+ if (!read_cache)
+ prt_str(out, "reads don't appear to be cached - safe\n");
+ else if (!fua_cached)
+ prt_str(out, "fua reads don't appear to be cached - safe\n");
+ else
+ prt_str(out, "fua reads appear to be cached - unsafe\n");
+err:
+ kfree(buf);
+ kfree(bio);
+ percpu_ref_put(&ca->io_ref[READ]);
+ bch_err_fn(c, ret);
+ return ret;
+}
+
SHOW(bch2_fs)
{
struct bch_fs *c = container_of(kobj, struct bch_fs, kobj);
@@ -637,37 +749,19 @@ static ssize_t sysfs_opt_store(struct bch_fs *c,
u64 v;
ret = bch2_opt_parse(c, opt, strim(tmp), &v, NULL) ?:
- bch2_opt_check_may_set(c, ca, id, v);
+ bch2_opt_hook_pre_set(c, ca, id, v);
kfree(tmp);
if (ret < 0)
goto err;
- bch2_opt_set_sb(c, ca, opt, v);
- bch2_opt_set_by_id(&c->opts, id, v);
-
- if (v &&
- (id == Opt_background_target ||
- (id == Opt_foreground_target && !c->opts.background_target) ||
- id == Opt_background_compression ||
- (id == Opt_compression && !c->opts.background_compression)))
- bch2_set_rebalance_needs_scan(c, 0);
+ bool changed = bch2_opt_set_sb(c, ca, opt, v);
- if (v && id == Opt_rebalance_enabled)
- rebalance_wakeup(c);
+ if (!ca)
+ bch2_opt_set_by_id(&c->opts, id, v);
- if (v && id == Opt_copygc_enabled &&
- c->copygc_thread)
- wake_up_process(c->copygc_thread);
-
- if (id == Opt_discard && !ca) {
- mutex_lock(&c->sb_lock);
- for_each_member_device(c, ca)
- opt->set_member(bch2_members_v2_get_mut(ca->disk_sb.sb, ca->dev_idx), v);
-
- bch2_write_super(c);
- mutex_unlock(&c->sb_lock);
- }
+ if (changed)
+ bch2_opt_hook_post_set(c, ca, 0, &c->opts, id);
ret = size;
err:
@@ -818,6 +912,9 @@ SHOW(bch2_dev)
if (attr == &sysfs_open_buckets)
bch2_open_buckets_to_text(out, c, ca);
+ if (attr == &sysfs_read_fua_test)
+ return bch2_read_fua_test(out, ca);
+
int opt_id = bch2_opt_lookup(attr->name);
if (opt_id >= 0)
return sysfs_opt_show(c, ca, opt_id, out);
@@ -874,6 +971,8 @@ struct attribute *bch2_dev_files[] = {
&sysfs_io_latency_stats_write,
&sysfs_congested,
+ &sysfs_read_fua_test,
+
/* debug: */
&sysfs_alloc_debug,
&sysfs_open_buckets,
generated by cgit v1.2.3 (git 2.46.0) at 2025-07-01 14:46:35 +0000