On 02/11/2010 02:34 PM, Trond Myklebust wrote:
On Thu, 2010-02-11 at 14:20 -0500, Chuck Lever wrote:
On 02/11/2010 02:14 PM, Trond Myklebust wrote:
On Thu, 2010-02-11 at 14:09 -0500, Chuck Lever wrote:
Close-to-open isn't needed for O_DIRECT files, since their data is
never cached. So if their attribute cache hasn't expired, skip the
GETATTR.
Don't we still want to ensure that the access cache is still valid?
Would it be reasonable/feasible to squelch the GETATTR but force an
ACCESS call from nfs_permission?
As long as the ACCESS call returns post-op attributes, then it is
reasonable to do this for NFSv3 (or for NFSv4 opendir()) in all cases.
I used to have patches for this, but was never able to show that the
resulting total number of GETATTR+ACCESS calls was much affected.
It probably doesn't make a whole lot of difference in this case either,
then. The client would generate a GETATTR which effectively refreshes
both the attribute cache and the access cache, or an ACCESS that does
almost the same.
The previous patch probably fixes the (by far) largest part of the
request overage here.
Does it make sense to drop this patch?
--
chuck[dot]lever[at]oracle[dot]com
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