From: Austin Chang <austin880625@gmail.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: dm-devel@redhat.com, Alasdair Kergon <agk@redhat.com>,
Mike Snitzer <snitzer@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dm-cache: document zeroing metadata device step
Date: Mon, 13 Jul 2020 05:10:45 +0800 [thread overview]
Message-ID: <20200712211045.GA332416@austin-fedora> (raw)
In-Reply-To: <20200712195932.GV12769@casper.infradead.org>
On Sun, Jul 12, 2020 at 08:59:32PM +0100, Matthew Wilcox wrote:
> On Mon, Jul 13, 2020 at 03:40:39AM +0800, Austin Chang wrote:
> > + # When using dmsetup directly instead of volume manager like lvm2,
> > + # the first 4k of the metadata device should be zeroed to indicate
> > + # empty metadata.
> > + dd if=/dev/zero of=/dev/mapper/metadata bs=4k conv=notrunc
>
> ... don't you need 'count=1' or you'll zero the entire device?
Oops, I copied the command I just used since zeroing the whole metadata
device didn't harm. But 'count=1' should match what I've just written.
I will send a v2 patch later
next prev parent reply other threads:[~2020-07-12 21:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-12 19:40 [PATCH] dm-cache: document zeroing metadata device step Austin Chang
2020-07-12 19:59 ` Matthew Wilcox
2020-07-12 21:10 ` Austin Chang [this message]
2020-07-12 21:47 ` [PATCH v2] " Austin Chang
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