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Message-Id: <20210712230530.29323-5-mcroce@linux.microsoft.com>
Date: Tue, 13 Jul 2021 01:05:28 +0200
From: Matteo Croce <mcroce@...ux.microsoft.com>
To: linux-block@...r.kernel.org, linux-fsdevel@...r.kernel.org,
Jens Axboe <axboe@...nel.dk>,
Christoph Hellwig <hch@...radead.org>
Cc: linux-kernel@...r.kernel.org,
Lennart Poettering <lennart@...ttering.net>,
Luca Boccassi <bluca@...ian.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
Damien Le Moal <damien.lemoal@....com>,
Tejun Heo <tj@...nel.org>,
Javier González <javier@...igon.com>,
Niklas Cassel <niklas.cassel@....com>,
Johannes Thumshirn <johannes.thumshirn@....com>,
Hannes Reinecke <hare@...e.de>,
Matthew Wilcox <willy@...radead.org>,
JeffleXu <jefflexu@...ux.alibaba.com>
Subject: [PATCH v5 4/6] block: export diskseq in sysfs
From: Matteo Croce <mcroce@...rosoft.com>
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: Christoph Hellwig <hch@....de>
Signed-off-by: Matteo Croce <mcroce@...rosoft.com>
---
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/<disk>/diskseq
+Date: February 2021
+Contact: Matteo Croce <mcroce@...rosoft.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@...hat.com>
diff --git a/block/genhd.c b/block/genhd.c
index 3126f8afe3b8..9ac41500caf9 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -985,6 +985,14 @@ 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);
@@ -997,6 +1005,7 @@ 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,
@@ -1042,6 +1051,7 @@ 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
--
2.31.1
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