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

Nick Piggin
2006-05-30T06:50:23Z

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.

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SUSE Labs, Novell Inc.
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