linux-ext4 - Re: [PATCH 1/6 v2] ext4: Update inode i

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Message-ID: <20140316032756.GA31988@thunk.org>
Date:	Sat, 15 Mar 2014 23:27:56 -0400
From:	tytso@....edu
To:	Lukas Czerner <lczerner@...hat.com>
Cc:	linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	xfs@....sgi.com
Subject: Re: [PATCH 1/6 v2] ext4: Update inode i_size after the preallocation

On Tue, Feb 25, 2014 at 08:14:34PM +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>

Thanks, applied.

					- Ted
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