From: Stefan Behrens <sbehrens@giantdisaster.de>
To: Liu Bo <liubo2009@cn.fujitsu.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v3 3/3] Btrfs: read device stats on mount, write modified ones during commit
Date: Thu, 17 May 2012 10:49:18 +0200 [thread overview]
Message-ID: <4FB4BB8E.9080503@giantdisaster.de> (raw)
In-Reply-To: <4FB459F0.3050502@cn.fujitsu.com>
On 05/17/2012 03:52, Liu Bo wrote:
> On 05/17/2012 12:50 AM, Stefan Behrens wrote:
>
>> The device statistics are written into the device tree with each
>> transaction commit. Only modified statistics are written.
>> When a filesystem is mounted, the device statistics for each involved
>> device are read from the device tree and used to initialize the
>> counters.
>
>
> Hi Stefan,
>
> Just scaned the patch for a while and got a question:
>
> Adding a new key type usually means changing the disk format,
> so have you done something for this?
Hi Liu,
New tree entries with new keys are added to the device tree. Old kernels
do not search for these keys and therefore ignore them. New kernels
(with this patch) search for these keys and read and write them, or
create them when required. That works fine.
next prev parent reply other threads:[~2012-05-17 8:50 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-16 16:50 [PATCH v3 0/3] Btrfs: add IO error device stats Stefan Behrens
2012-05-16 16:50 ` [PATCH v3 1/3] Btrfs: add device counters for detected IO and checksum errors Stefan Behrens
2012-05-16 16:50 ` [PATCH v3 2/3] Btrfs: add ioctl to get and reset the device stats Stefan Behrens
2012-05-16 16:50 ` [PATCH v3 3/3] Btrfs: read device stats on mount, write modified ones during commit Stefan Behrens
2012-05-17 1:52 ` Liu Bo
2012-05-17 8:49 ` Stefan Behrens [this message]
2012-05-18 11:57 ` David Sterba
2012-05-21 14:57 ` Stefan Behrens
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=4FB4BB8E.9080503@giantdisaster.de \
--to=sbehrens@giantdisaster.de \
--cc=linux-btrfs@vger.kernel.org \
--cc=liubo2009@cn.fujitsu.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.