On Fri, Jun 01, 2007 at 03:59:51PM +1000, Neil Brown wrote:

On Friday June 1, dgc@sgi.com wrote:

quoted

On Thu, May 31, 2007 at 02:31:21PM -0400, Phillip Susi wrote:

quoted

David Chinner wrote:

quoted

That sounds like a good idea - we can leave the existing
WRITE_BARRIER behaviour unchanged and introduce a new WRITE_ORDERED
behaviour that only guarantees ordering. The filesystem can then
choose which to use where appropriate....

So what if you want a synchronous write, but DON'T care about the order? 

submit_bio(WRITE_SYNC, bio);

Already there, already used by XFS, JFS and direct I/O.

Are you sure?

You seem to be saying that WRITE_SYNC causes the write to be safe on
media before the request returns.

Sorry, I wasn't really all that clear :/

What I'm saying the *interface* for higher layer to tell the block layers
that a sync write is being executed is already there. i.e. we can already
tell the block layer that we are doing a synchronous I/O.

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group