Re: [PATCH v2 1/4] define PAGECACHE_TAG_* as enumeration under include/uapi

[Dave Chinner]

On Thu, Jul 03, 2014 at 05:52:12PM -0400, Naoya Horiguchi wrote:
> We need the pagecache tags to be exported to userspace later in this
> series for fincore(2), so this patch moves the definition to the new
> include file for preparation. We also use the number of pagecache tags,
> so this patch also adds it.
> 
> Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>

NACK.

The radix tree tags are deeply internal implementation details.
They are an artifact of the current mark-and-sweep writeback
algorithm, and as such should never, ever be exposed to userspace,
let alone fixed in an ABI we need to support forever more.

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx
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