Re: [rfc][patch] remove racy sync_page?

From: Nick Piggin
Date: Tue May 30 2006 - 02:49:40 EST


Nick Piggin wrote:
Josef Sipek wrote:

On Mon, May 29, 2006 at 07:34:09PM +1000, Nick Piggin wrote:
...

Can we get rid of the whole thing, confusing memory barriers and all?
Nobody uses anything but the default sync_page



I feel like I must say this: there are some file systems that live
outside the kernel (at least for now) that do _NOT_ use the default
sync_page. All the stackable file systems that are based on FiST [1],
such as Unionfs [2] and eCryptfs (currently in -mm) [3] (respective
authors CC'd). As an example, Unionfs must decide which lower file
system page to sync (since it may have several to chose from).


OK, noted. Thanks. Luckily for them it looks like sync_page might
stay for other reasons (eg. raid) ;)

Ah, no: that's the backing dev's unplug_fn. sync_page is always the
same. And it has definite bugs now that splice has been merged.

--
SUSE Labs, Novell Inc.
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