Re: [PATCH] btrfs: sysfs: export dev stats in devinfo directory
From: Anand Jain <hidden>
Date: 2021-06-04 13:41:25
On 4/6/21 9:20 pm, David Sterba wrote:
The device stats can be read by ioctl, wrapped by command 'btrfs device stats'. Provide another source where to read the information in /sys/fs/btrfs/FSID/devinfo/DEVID/stats .
The planned stat here is errors stat. So why not rename this to error_stats?
The format is a list of 'key value' pairs one per line, which is common in other stat files. The names are the same as used in other device stat outputs.
Nice! Thanks, Anand
quoted hunk ↗ jump to hunk
The stats are all in one file as it's the snapshot of all available stats. The 'one value per file' is not very suitable here. The stats should be valid right after the stats item is read from disk, shortly after initializing the device, but in any case also print the validity status. Signed-off-by: David Sterba <dsterba@suse.com> --- fs/btrfs/sysfs.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 4b508938e728..3d4c806c4f73 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c@@ -1495,11 +1495,39 @@ static ssize_t btrfs_devinfo_writeable_show(struct kobject *kobj, } BTRFS_ATTR(devid, writeable, btrfs_devinfo_writeable_show); +static ssize_t btrfs_devinfo_stats_show(struct kobject *kobj, + struct kobj_attribute *a, char *buf) +{ + struct btrfs_device *device = container_of(kobj, struct btrfs_device, + devid_kobj); + + /* + * Print all at once so we get a snapshot of all values from the same + * time. Keep them in sync and in order of definition of + * btrfs_dev_stat_values. + */ + return scnprintf(buf, PAGE_SIZE, + "stats_valid %d\n", + "write_errs %d\n" + "read_errs %d\n" + "flush_errs %d\n" + "corruption_errs %d\n" + "generation_errs %d\n", + !!(device->dev_stats_valid), + btrfs_dev_stat_read(device, BTRFS_DEV_STAT_WRITE_ERRS), + btrfs_dev_stat_read(device, BTRFS_DEV_STAT_READ_ERRS), + btrfs_dev_stat_read(device, BTRFS_DEV_STAT_FLUSH_ERRS), + btrfs_dev_stat_read(device, BTRFS_DEV_STAT_CORRUPTION_ERRS), + btrfs_dev_stat_read(device, BTRFS_DEV_STAT_GENERATION_ERRS)); +} +BTRFS_ATTR(devid, stats, btrfs_devinfo_stats_show); + static struct attribute *devid_attrs[] = { BTRFS_ATTR_PTR(devid, in_fs_metadata), BTRFS_ATTR_PTR(devid, missing), BTRFS_ATTR_PTR(devid, replace_target), BTRFS_ATTR_PTR(devid, scrub_speed_max), + BTRFS_ATTR_PTR(devid, stats), BTRFS_ATTR_PTR(devid, writeable), NULL };