From: "Darrick J. Wong" <djwong@us.ibm.com>
To: "Ted Ts'o" <tytso@mit.edu>
Cc: Yongqiang Yang <xiaoqiangnk@gmail.com>, linux-ext4@vger.kernel.org
Subject: Re: [PATCH 4/5] ext4: flush journal when switching from journal data mode
Date: Thu, 29 Dec 2011 13:01:53 -0800 [thread overview]
Message-ID: <20111229210153.GN8233@tux1.beaverton.ibm.com> (raw)
In-Reply-To: <20111228185643.GD12370@thunk.org>
On Wed, Dec 28, 2011 at 01:56:43PM -0500, Ted Ts'o wrote:
> On Tue, Nov 15, 2011 at 04:07:53PM +0800, Yongqiang Yang wrote:
> > When switching from journal data mode, the data blocks
> > in journal will have no revoke record. Thus, data could be
> > corrupted during replay. However, there is no such problem in
> > switching to journal data mode. So we flush journal only in
> > the case that swithes from journal data mode.
> >
> > Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
>
> Applied, with a slightly different (and more explanatory commit
> message):
>
> ext4: flush journal when switching from data=journal mode
>
> From: Yongqiang Yang <xiaoqiangnk@gmail.com>
>
> It's necessary to flush the journal when switching away from
> data=journal mode. This is because there are no revoke records when
> we are data blocks are journalled,
Minor nit, but did you mean "when data blocks are journalled" ?
--D
> which are required in the other journal modes.
>
> However, it is not necessary to flush the journal when switching into
> data=journal mode, and flushing the journal is expensive. So let's
> avoid it in that case.
>
> Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
>
> - Ted
> --
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>
next prev parent reply other threads:[~2011-12-29 21:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-15 8:07 [PATCH 1/5] ext4: allocate delalloc blocks before changing journal mode Yongqiang Yang
2011-11-15 8:07 ` [PATCH 2/5] ext4: let ext4 journal deletion of data blocks Yongqiang Yang
2011-12-28 17:23 ` Ted Ts'o
2011-12-30 14:59 ` Yongqiang Yang
2011-12-30 15:05 ` Ted Ts'o
2011-11-15 8:07 ` [PATCH 3/5] ext4: let ext4_free_blocks handle multiblock correctly Yongqiang Yang
2011-12-28 17:23 ` Ted Ts'o
2011-11-15 8:07 ` [PATCH 4/5] ext4: flush journal when switching from journal data mode Yongqiang Yang
2011-12-28 18:56 ` Ted Ts'o
2011-12-29 21:01 ` Darrick J. Wong [this message]
2011-12-30 14:43 ` Yongqiang Yang
2011-12-30 14:57 ` Ted Ts'o
2011-11-15 8:07 ` [PATCH 5/5] jbd2: clear revoked flag on buffers before a new transaction started Yongqiang Yang
2011-12-28 23:25 ` Ted Ts'o
2011-12-09 3:31 ` [PATCH 1/5] ext4: allocate delalloc blocks before changing journal mode Toshiyuki Okajima
2011-12-28 17:14 ` Ted Ts'o
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