linux-ext4 - Re: [PATCH 1/3 v3] ext4: Update inode i

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Message-ID: <20140325000521.GA2399@thunk.org>
Date:	Mon, 24 Mar 2014 20:05:21 -0400
From:	tytso@....edu
To:	Lukas Czerner <lczerner@...hat.com>
Cc:	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 1/3 v3] ext4: Update inode i_size after the preallocation

On Tue, Mar 18, 2014 at 04:34:31PM +0100, Lukas Czerner wrote:
> Currently in ext4_fallocate we would update inode size, c_time and sync
> the file with every partial allocation which is entirely unnecessary. It
> is true that if the crash happens in the middle of truncate we might end
> up with unchanged i size, or c_time which I do not think is really a
> problem - it does not mean file system corruption in any way. Note that
> xfs is doing things the same way e.g. update all of the mentioned after
> the allocation is done.
> 
> This commit moves all the updates after the allocation is done. In
> addition we also need to change m_time as not only inode has been change
> bot also data regions might have changed (unwritten extents). However
> m_time will be only updated when i_size changed.
> 
> Also we do not need to be paranoid about changing the c_time only if the
> actual allocation have happened, we can change it even if we try to
> allocate only to find out that there are already block allocated. It's
> not really a big deal and it will save us some additional complexity.
> 
> Also use ext4_debug, instead of ext4_warning in #ifdef EXT4FS_DEBUG
> section.
> 
> Signed-off-by: Lukas Czerner <lczerner@...hat.com>

I noticed I didn't explicitly ack this in patchwork, but as you've
probably noticed, I've merged the v3 version of these patches into the
ext4 patch queue.

Cheers,

					- Ted
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