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From: tytso@mit.edu
To: Duane Griffin <duaneg@dghda.com>
Cc: Andreas Dilger <andreas.dilger@lustre.org>,
	Eric Sandeen <sandeen@redhat.com>,
	ext4 development <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH 2/2] ext4: journal superblock modifications in ext4_statfs()
Date: Mon, 23 Nov 2009 09:26:58 -0500	[thread overview]
Message-ID: <20091123142658.GE2532@thunk.org> (raw)
In-Reply-To: <e9e943910911230357r338bcb45ga6962c92d32fca4a@mail.gmail.com>

On Mon, Nov 23, 2009 at 11:57:44AM +0000, Duane Griffin wrote:
> Unfortunately you can't just blindly give back the journalled block:
> it may have been escaped. So you need to read in the block from the
> journal, unescape it if required, then give it back.

Good point; this is going to make supporting a read-only mount that
doesn't replay the journal very difficult to implement for
data=journal mode, since it would mean intercepting the actual block
I/O read functions for data reads, which is outside of fs/ext4 in the
generic fs/ and mm/ functions.  Doing it for metadata blocks will be
annoying, but at least it's all inside fs/ext4.

					- Ted

  reply	other threads:[~2009-11-23 14:27 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-06 22:33 [PATCH 2/2] ext4: journal superblock modifications in ext4_statfs() Eric Sandeen
2009-11-07  0:26 ` Andreas Dilger
2009-11-07  1:08   ` Eric Sandeen
2009-11-08 21:48   ` Theodore Tso
2009-11-08 22:09     ` Eric Sandeen
2009-11-09 12:53       ` Theodore Tso
2009-11-09 17:55         ` Andreas Dilger
2009-11-09  4:41     ` Andreas Dilger
2009-11-15  3:29       ` Theodore Tso
2009-11-16 23:38         ` Andreas Dilger
2009-11-19 19:08           ` tytso
2009-11-23 11:57             ` Duane Griffin
2009-11-23 14:26               ` tytso [this message]
2009-11-23 14:40                 ` Duane Griffin

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