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[176.246.29.26]) by smtp.gmail.com with ESMTPSA id r2sm2659458wrv.39.2021.06.23.03.59.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Jun 2021 03:59:54 -0700 (PDT) From: Matteo Croce To: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe Cc: linux-kernel@vger.kernel.org, Lennart Poettering , Luca Boccassi , Alexander Viro , Damien Le Moal , Tejun Heo , =?utf-8?q?Javier_Gonz=C3=A1lez?= , Niklas Cassel , Johannes Thumshirn , Hannes Reinecke , Matthew Wilcox , Christoph Hellwig , JeffleXu Subject: [PATCH v3 4/6] block: export diskseq in sysfs Date: Wed, 23 Jun 2021 12:58:56 +0200 Message-Id: <20210623105858.6978-5-mcroce@linux.microsoft.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210623105858.6978-1-mcroce@linux.microsoft.com> References: <20210623105858.6978-1-mcroce@linux.microsoft.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Matteo Croce 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 Signed-off-by: Matteo Croce --- Documentation/ABI/testing/sysfs-block | 12 ++++++++++++ block/genhd.c | 11 +++++++++++ 2 files changed, 23 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 610dd86fd4b6..768d8d5d1eca 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1680,6 +1680,7 @@ static void disk_check_events(struct disk_events *ev, * events_async : list of events which can be detected w/o polling * (always empty, only for backwards compatibility) * events_poll_msecs : polling interval, 0: disable, -1: system default + * diskseq : disk sequence number, since boot */ static ssize_t __disk_events_show(unsigned int events, char *buf) { @@ -1750,16 +1751,26 @@ static ssize_t disk_events_poll_msecs_store(struct device *dev, return count; } +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 const DEVICE_ATTR(events, 0444, disk_events_show, NULL); static const DEVICE_ATTR(events_async, 0444, disk_events_async_show, NULL); static const DEVICE_ATTR(events_poll_msecs, 0644, disk_events_poll_msecs_show, disk_events_poll_msecs_store); +static const DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL); static const struct attribute *disk_sysfs_attrs[] = { &dev_attr_events.attr, &dev_attr_events_async.attr, &dev_attr_events_poll_msecs.attr, + &dev_attr_diskseq.attr, NULL, };