On Mon, Aug 31, 2009 at 06:29:50PM -0400, Trond Myklebust wrote:
> On Mon, 2009-08-31 at 18:21 -0400, Trond Myklebust wrote:
> > On Mon, 2009-08-31 at 18:03 -0400, J. Bruce Fields wrote:
> > > If you want to do this, you probably also want to turn off the previous
> > > exfslocs.locations check in the same function. Otherwise we claim
> > > support for the attribute but then never actually return it.
> >
> > ...why is that a problem? Clients that conform to RFC3530 are perfectly
> > capable of dealing with that case. The point is that if you say "I don't
> > support this attribute", then the client will _never_ be allowed to
> > check it.
>
> Put differently: not setting the fs_locations bit in the supp_attr
> information is equivalent to telling the client that it shouldn't ask
> for it, and there is no time limit on that prohibition...
OK, makes sense. There's no explicit time limit on the fs_locations
data either, but there's at least some expectation that it could change.
To me it would seem permissible, however, for a client to interpret a
GETATTR reply which turns off a requested FS_LOCATIONS bit as stating a
permanent lack of support for the attribute, rather than necessarily as
stating that the list of fs_locations is currently zero-length. So why
not make it unambiguous and return a zero-length list?
With that and a corrected comment, we'd have the appended.
--b.
commit dfe14eaccdf05090b802be52ef93764387001331
Author: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Date: Mon Aug 31 15:16:11 2009 -0400
NFSD: Fix a bug in the NFSv4 'supported attrs' mandatory attribute
The fact that the filesystem doesn't currently list any alternate
locations does _not_ imply that the fs_locations attribute should be
marked as "unsupported".
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index fdf632b..20c5e3d 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1793,11 +1793,6 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
goto out_nfserr;
}
}
- if (bmval0 & FATTR4_WORD0_FS_LOCATIONS) {
- if (exp->ex_fslocs.locations == NULL) {
- bmval0 &= ~FATTR4_WORD0_FS_LOCATIONS;
- }
- }
if ((buflen -= 16) < 0)
goto out_resource;
@@ -1825,8 +1820,6 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
goto out_resource;
if (!aclsupport)
word0 &= ~FATTR4_WORD0_ACL;
- if (!exp->ex_fslocs.locations)
- word0 &= ~FATTR4_WORD0_FS_LOCATIONS;
if (!word2) {
WRITE32(2);
WRITE32(word0);
--
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