Subject: Re: [PATCH] FAT: optimize FSINFO writeback
From: "Steven J. Magnani" <steve@digidescorp.com>
Reply-To: steve@digidescorp.com
To: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <87ocs5h238.fsf@devron.myhome.or.jp>
References: <1246392130-4261-1-git-send-email-steve@digidescorp.com>
	 <87ocs5h238.fsf@devron.myhome.or.jp>
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Organization: Digital Design Corporation
Date: Tue, 30 Jun 2009 17:19:05 -0500
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On Wed, 2009-07-01 at 05:57 +0900, OGAWA Hirofumi wrote:
> steve@digidescorp.com writes:
> 
> > Only write the FSINFO block back to disk when its contents change.
> > This optimization can be important when the underlying physical media
> > can wear out, i.e. Flash.
> 
> I have no objection to this though.  Was this tested on recent version?

I tested it on 2.6.30.

> Well, now, we are using sb->s_dirty for fsinfo, so I'm wondering why
> this happen frequently.

My scenario was modifying a sector of an existing file and using
fdatasync() to flush it. The FSINFO sector was being updated even though
nothing about the FAT layout had changed.

> 
> Thanks.

Regards,
------------------------------------------------------------------------
 Steven J. Magnani               "I claim this network for MARS!
 www.digidescorp.com              Earthling, return my space modulator!"

 #include <standard.disclaimer>


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