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Date: Fri, 27 Mar 2009 10:13:33 -0400
From: Theodore Tso <tytso@mit.edu>
To: Jens Axboe <jens.axboe@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
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Subject: Re: Linux 2.6.29
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On Fri, Mar 27, 2009 at 08:57:23AM +0100, Jens Axboe wrote:
> 
> Here's a simple patch that does that. Not even tested, it compiles. Note
> that file systems that currently do blkdev_issue_flush() in their
> ->sync() should then get it removed.
> 

That's going to be a mess.  Ext3 implements an fsync() by requesting a
journal commit, and then waiting for the commit to have taken place.
The commit happens in another thread, kjournald.  Knowing when it's OK
not to do a blkdev_issue_flush() because the commit was triggered by
an fsync() is going to be really messy.  Could we at least have a flag
in struct super which says, "We'll handle the flush correctly, please
don't try to do it for us?"

						- Ted

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