Subject: Re: wd, disk write cache, sync cache, and softdep.
To: Bill Studenmund <>
From: Jason Thorpe <>
List: tech-kern
Date: 12/16/2004 14:00:30
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On Dec 16, 2004, at 12:06 PM, Bill Studenmund wrote:

> Metadata updates.
> If the upper level really cares about ordering, it should set this 
> flag.

Well, no.

It's more complicated than that.

Ordering is only part of the issue.  It's "data that is written to the 
drive really bloody well is written to stable storage".  This is of the 
utmost importance in the presence of, say, a journaling file system ... 
the file system may not be recoverable if the journal becomes corrupted 
due to power failure at the drive wiping out data that hasn't landed on 
the platters yet.

         -- Jason R. Thorpe <>

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