From: Christoph Hellwig <hch@infradead.org>
To: Heinz Mauelshagen <heinzm@redhat.com>
Cc: John Dorminy <jdorminy@redhat.com>,
Christoph Hellwig <hch@infradead.org>,
axboe@kernel.dk,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Mike Snitzer <snitzer@redhat.com>,
linux-block@vger.kernel.org, dm-devel@redhat.com,
Zhang Xiaoxu <zhangxiaoxu5@huawei.com>,
Alasdair G Kergon <agk@redhat.com>
Subject: Re: [dm-devel] block: Fix a WRITE SAME BUG_ON
Date: Fri, 1 Feb 2019 08:18:03 -0800 [thread overview]
Message-ID: <20190201161803.GA21124@infradead.org> (raw)
In-Reply-To: <f7b05928-316c-4c73-b04b-bba38ea60b27@redhat.com>
On Fri, Feb 01, 2019 at 05:03:40PM +0100, Heinz Mauelshagen wrote:
> On 2/1/19 3:09 PM, John Dorminy wrote:
> > I didn't know such a thing existed... does it work on any block
> > device? Where do I read more about this?
>
>
> Use sg_write_same(8) from package sg3_utils.
>
> For instance 'sg_write_same --in=foobarfile --lba=0 --num=20000
> --xferlen=512 /dev/sdwhatever'
>
> will read the pattern to write same from file 'foobarfile' with length
> explicitely set to 512 bytes
> (rather than derived from foobarfile's size) and write it 20000 times
> starting at LBA 0 to /dev/sdwhatever.
Yeah. Note that this will only work on SCSI disks (and maybe ATA
for a very specific corner case). But for actual devices and not
remappers the same is true of REQ_OP_WRITE_SAME.
next prev parent reply other threads:[~2019-02-01 16:18 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190125021107.4595-1-zhangxiaoxu5@huawei.com>
2019-01-26 11:17 ` [dm-devel] [v2] block: Fix a WRITE SAME BUG_ON John Dorminy
2019-01-28 5:48 ` zhangxiaoxu (A)
2019-01-28 22:14 ` Mike Snitzer
2019-01-29 4:54 ` Martin K. Petersen
2019-01-29 8:52 ` Christoph Hellwig
2019-01-30 6:50 ` zhangxiaoxu (A)
2019-01-30 14:08 ` John Dorminy
2019-01-31 0:58 ` zhangxiaoxu (A)
2019-01-31 2:23 ` Martin K. Petersen
2019-01-31 10:39 ` Christoph Hellwig
2019-01-31 19:41 ` John Dorminy
2019-02-01 7:35 ` Christoph Hellwig
2019-02-01 14:09 ` John Dorminy
2019-02-01 16:03 ` [dm-devel] " Heinz Mauelshagen
2019-02-01 16:18 ` Christoph Hellwig [this message]
2019-02-12 3:11 ` zhangxiaoxu (A)
2019-02-14 2:31 ` Martin K. Petersen
2019-02-14 9:36 ` zhangxiaoxu (A)
2019-02-18 14:10 ` zhangxiaoxu (A)
2019-02-19 23:10 ` Martin K. Petersen
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