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To: Chris Wedgwood <cw@f00f.org>
Cc: Al Boldi <a1426z@gawab.com>, "'Nathan Scott'" <nathans@sgi.com>,
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Subject: Re: SPAM: Re: XFS corruption during power-blackout
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From: Andi Kleen <ak@suse.de>
Date: 30 Jun 2005 01:11:03 +0200
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Chris Wedgwood <cw@f00f.org> writes:

> If caching is enabled I still lose data.  Linux does have a concept of
> write barriers but these are presently not implemented for XFS right
> now.

I implemented them some time ago for log writes in XFS. Not for fsync though,
although fsync usually does a log write afterwards so it should work
in practice too. fdatasync might not.

Don't know if the code hasn't bit rotted away and it also was a bit
dumb. It was definitely there at some point.

But then a lot of ATA disks and SCSI don't support barriers. Or at least
the IDE barrier tests fails on several of my machines.

-Andi