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From:   Matteo Croce <mcroce@linux.microsoft.com>
To:     linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org,
        Lennart Poettering <lennart@poettering.net>,
        Luca Boccassi <bluca@debian.org>, Jens Axboe <axboe@kernel.dk>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Damien Le Moal <damien.lemoal@wdc.com>,
        Tejun Heo <tj@kernel.org>,
        =?UTF-8?q?Javier=20Gonz=C3=A1lez?= <javier@javigon.com>,
        Niklas Cassel <niklas.cassel@wdc.com>,
        Johannes Thumshirn <johannes.thumshirn@wdc.com>,
        Hannes Reinecke <hare@suse.de>
Subject: [PATCH -next 2/5] block: add ioctl to read the disk sequence number
Date:   Mon, 15 Mar 2021 21:02:39 +0100
Message-Id: <20210315200242.67355-3-mcroce@linux.microsoft.com>
In-Reply-To: <20210315200242.67355-1-mcroce@linux.microsoft.com>
References: <20210315200242.67355-1-mcroce@linux.microsoft.com>
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From: Matteo Croce <mcroce@microsoft.com>

Add a new BLKGETDISKSEQ ioctl which retrieves the disk sequence number
from the genhd structure.

Signed-off-by: Matteo Croce <mcroce@microsoft.com>
---
 block/ioctl.c           | 2 ++
 include/uapi/linux/fs.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/block/ioctl.c b/block/ioctl.c
index ff241e663c01..266315d00942 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -467,6 +467,8 @@ static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode,
 				BLKDEV_DISCARD_SECURE);
 	case BLKZEROOUT:
 		return blk_ioctl_zeroout(bdev, mode, arg);
+	case BLKGETDISKSEQ:
+		return put_u64(argp, bdev->bd_disk->diskseq);
 	case BLKREPORTZONE:
 		return blkdev_report_zones_ioctl(bdev, mode, cmd, arg);
 	case BLKRESETZONE:
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index f44eb0a04afd..5dc72bbdd9b7 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -184,6 +184,7 @@ struct fsxattr {
 #define BLKSECDISCARD _IO(0x12,125)
 #define BLKROTATIONAL _IO(0x12,126)
 #define BLKZEROOUT _IO(0x12,127)
+#define BLKGETDISKSEQ _IOR(0x12,128,__u64)
 /*
  * A jump here: 130-131 are reserved for zoned block devices
  * (see uapi/linux/blkzoned.h)
-- 
2.30.2