Commit 13927b31 authored by Matteo Croce's avatar Matteo Croce Committed by Jens Axboe
Browse files

block: export diskseq in sysfs 



Add a new sysfs handle to export the new diskseq value.
Place it in <sysfs>/block/<disk>/diskseq and document it.

    $ grep . /sys/class/block/*/diskseq
    /sys/class/block/loop0/diskseq:13
    /sys/class/block/loop1/diskseq:14
    /sys/class/block/loop2/diskseq:5
    /sys/class/block/loop3/diskseq:6
    /sys/class/block/ram0/diskseq:1
    /sys/class/block/ram1/diskseq:2
    /sys/class/block/vda/diskseq:7

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMatteo Croce <mcroce@microsoft.com>
Tested-by: default avatarLuca Boccassi <bluca@debian.org>
Link: https://lore.kernel.org/r/20210712230530.29323-5-mcroce@linux.microsoft.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7957d93b

Documentation/ABI/testing/sysfs-block

+12 −0
Original line number Diff line number Diff line
@@ -28,6 +28,18 @@ Description: 
		For more details refer Documentation/admin-guide/iostats.rst





What:		/sys/block/<disk>/diskseq

Date:		February 2021

Contact:	Matteo Croce <mcroce@microsoft.com>

Description:

		The /sys/block/<disk>/diskseq files reports the disk

		sequence number, which is a monotonically increasing

		number assigned to every drive.

		Some devices, like the loop device, refresh such number

		every time the backing file is changed.

		The value type is 64 bit unsigned.





What:		/sys/block/<disk>/<part>/stat

Date:		February 2008

Contact:	Jerome Marchand <jmarchan@redhat.com>

block/genhd.c

+10 −0
Original line number Diff line number Diff line
@@ -977,6 +977,14 @@ static ssize_t disk_discard_alignment_show(struct device *dev, 
	return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));

}



static ssize_t diskseq_show(struct device *dev,

			    struct device_attribute *attr, char *buf)

{

	struct gendisk *disk = dev_to_disk(dev);



	return sprintf(buf, "%llu\n", disk->diskseq);

}



static DEVICE_ATTR(range, 0444, disk_range_show, NULL);

static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);

static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
@@ -989,6 +997,7 @@ static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL); 
static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);

static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);

static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);

static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL);



#ifdef CONFIG_FAIL_MAKE_REQUEST

ssize_t part_fail_show(struct device *dev,
@@ -1034,6 +1043,7 @@ static struct attribute *disk_attrs[] = { 
	&dev_attr_events.attr,

	&dev_attr_events_async.attr,

	&dev_attr_events_poll_msecs.attr,

	&dev_attr_diskseq.attr,

#ifdef CONFIG_FAIL_MAKE_REQUEST

	&dev_attr_fail.attr,

#endif