From: Matthew Wilcox <willy@infradead.org>
To: Austin Chang <austin880625@gmail.com>
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: Sun, 12 Jul 2020 20:59:32 +0100 [thread overview]
Message-ID: <20200712195932.GV12769@casper.infradead.org> (raw)
In-Reply-To: <20200712194039.329035-1-austin880625@gmail.com>
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?
> dmsetup create my_cache --table '0 41943040 cache /dev/mapper/metadata \
> /dev/mapper/ssd /dev/mapper/origin 512 1 writeback default 0'
> dmsetup create my_cache --table '0 41943040 cache /dev/mapper/metadata \
> --
> 2.26.2
>
next prev parent reply other threads:[~2020-07-12 19:59 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 [this message]
2020-07-12 21:10 ` Austin Chang
2020-07-12 21:47 ` [PATCH v2] " Austin Chang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200712195932.GV12769@casper.infradead.org \
--to=willy@infradead.org \
--cc=agk@redhat.com \
--cc=austin880625@gmail.com \
--cc=corbet@lwn.net \
--cc=dm-devel@redhat.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=snitzer@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox