Re: [PATCH v3 01/10] svcrdma: Do not write xdr_buf::tail in a Write chunk

[Chuck Lever <chuck.lever@oracle.com>]

> On Feb 22, 2016, at 1:35 PM, Chuck Lever <chuck.lever@oracle.com> wrote:
> 
> 
>> On Feb 22, 2016, at 1:32 PM, bfields@fieldses.org wrote:
>> 
>> On Thu, Feb 18, 2016 at 12:43:53PM -0500, Chuck Lever wrote:
>>> The fix is to send only the contents of the xdr_buf's page list in
>>> a Write chunk.
>> 
>> This isn't quite right either.  A large-enough non-readlike reply will
>> use the page list if that's the only way to fit the reply.
>> 
>> You might be able to hit such cases, for example, using nfs4_getfacl on
>> a file with a sufficiently large ACL.
> 
> Clients provide a write chunk only for READ and READLINK.
> No way to hit this with GETFACL unless the client is doing
> something wrong.

OK, I see your point: and yes, I agree. The next revision
of the patch is more careful about trimming the page list
pad _only_ for the write chunk case, not for the reply case,
which is what you hit with GETFACL.


> Anyway, I've got another revision of this work coming, this
> time it should be a complete fix.
> 
> Thanks as always for your careful review!
> 
> --
> Chuck Lever
> 
> 
> 
> 
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--
Chuck Lever