Subject: Re: letting userland issue FUA writes
To: Bill Studenmund <>
From: Pavel Cahyna <>
List: tech-kern
Date: 03/15/2006 17:23:51
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.
> The main question I have is what kind of user-level interfaces exist for 
> this? I certainly could cook up a new system call, but I would much rather 
> 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 
to be committed to stable storage."

Is this semantics different from FUA?

Pavel Cahyna