Subject: Re: letting userland issue FUA writes
To: None <,>
From: Bill Studenmund <>
List: tech-kern
Date: 03/15/2006 16:30:59
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On Wed, Mar 15, 2006 at 05:23:51PM +0100, Pavel Cahyna wrote:
> On Tue, Mar 14, 2006 at 06:35:46PM -0800, Bill Studenmund wrote:
> > I'm interested in adding infrastructure so that applications can issue=
> > writes that have the FUA (Force Unit Access) bit set. SCSI CDBs handle=
> > this, as do some RAID cards.
> >=20
> > The main question I have is what kind of user-level interfaces exist fo=
> > this? I certainly could cook up a new system call, but I would much rat=
> > use prior art. My simplistic attempt at googling for this failed. Does=
> > anyone else have suggestions?
> O_DSYNC is documented as: "each write will wait for the file data=20
> to be committed to stable storage."
> Is this semantics different from FUA?

Not really. However I really want a system call where I can request this=20
on a per-call basis. Otherwise I have to have two open file descriptors,=20
one with and one without this flag set. That seems kinda silly.

Take care,


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