Re: [PATCH] scsi/sata write barrier support

[Jeff Garzik]

Doug Maxey wrote:
> On Thu, 27 Jan 2005 13:02:48 +0100, Jens Axboe wrote:
>
> > Hi,
> >
> > For the longest time, only the old PATA drivers supported barrier writes
> > with journalled file systems. This patch adds support for the same type
> > of cache flushing barriers that PATA uses for SCSI, to be utilized with
> > libata. 
>
>
> What, if any mechanism supports changing the underlying write cache?  
>
> That is, assuming this is common across PATA and SCSI drives, and it is 
> possible to turn the cache off on the IDE drives, would switching the 
> cache underneath require completing the inflight IO?

[ignoring your question, but it made me think...]


I am thinking the barrier support should know if the write cache is 
disabled (some datacenters do this), and avoid flushing if so?

	Jeff


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