linux-ext4 - Re: [PATCH] ext4: Make non-journal fsync work properly. REPOST

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Message-ID: <20090910025519.GJ24951@mit.edu>
Date:	Wed, 9 Sep 2009 22:55:19 -0400
From:	Theodore Tso <tytso@....edu>
To:	Frank Mayhar <fmayhar@...gle.com>
Cc:	linux-ext4@...r.kernel.org
Subject: Re: [PATCH] ext4: Make non-journal fsync work properly. REPOST

On Wed, Sep 09, 2009 at 10:34:24AM -0700, Frank Mayhar wrote:
> Teach ext4_write_inode() and ext4_do_update_inode() about non-journal
> mode:  If we're not using a journal, ext4_write_inode() now calls
> ext4_do_update_inode() (after getting the iloc via ext4_get_inode_loc())
> with a new "do_sync" parameter.  If that parameter is nonzero _and_ we're
> not using a journal, ext4_do_update_inode() calls sync_dirty_buffer()
> instead of ext4_handle_dirty_metadata().
> 
> This problem was found in power-fail testing, checking the amount of
> loss of files and blocks after a power failure when using fsync() and
> when not using fsync().  It turned out that using fsync() was actually
> worse than not doing so, possibly because it increased the likelihood
> that the inodes would remain unflushed and would therefore be lost at
> the power failure.
> 
> Signed-off-by: Frank Mayhar <fmayhar@...gle.com>

Added to the ext4 patch queue, thanks.

					- Ted
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