From 13927b31b13f3c6556221eff3487247bd3c7a245 Mon Sep 17 00:00:00 2001 From: Matteo Croce Date: Tue, 13 Jul 2021 01:05:28 +0200 Subject: [PATCH] block: export diskseq in sysfs Add a new sysfs handle to export the new diskseq value. Place it in /block//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: Christoph Hellwig Signed-off-by: Matteo Croce Tested-by: Luca Boccassi Link: https://lore.kernel.org/r/20210712230530.29323-5-mcroce@linux.microsoft.com Signed-off-by: Jens Axboe --- Documentation/ABI/testing/sysfs-block | 12 ++++++++++++ block/genhd.c | 10 ++++++++++ 2 files changed, 22 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block index e34cdeeeb9d4..a0ed87386639 100644 --- a/Documentation/ABI/testing/sysfs-block +++ b/Documentation/ABI/testing/sysfs-block @@ -28,6 +28,18 @@ Description: For more details refer Documentation/admin-guide/iostats.rst +What: /sys/block//diskseq +Date: February 2021 +Contact: Matteo Croce +Description: + The /sys/block//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///stat Date: February 2008 Contact: Jerome Marchand diff --git a/block/genhd.c b/block/genhd.c index e1b2f898d790..a4817e42f3a3 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -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