[PATCH v1 2/3] NFSD: Clear TIME_DELEG in the suppattr_exclcreat bitmap

[Chuck Lever <cel@kernel.org>]

From: Chuck Lever <chuck.lever@oracle.com>

From RFC 8881:

5.8.1.14. Attribute 75: suppattr_exclcreat

> The bit vector that would set all REQUIRED and RECOMMENDED
> attributes that are supported by the EXCLUSIVE4_1 method of file
> creation via the OPEN operation. The scope of this attribute
> applies to all objects with a matching fsid.

There's nothing in RFC 8881 that states that suppattr_exclcreat is
or is not allowed to contain bits for attributes that are clear in
the reported supported_attrs bitmask. But it doesn't make sense for
an NFS server to indicate that it /doesn't/ implement an attribute,
but then also indicate that clients /are/ allowed to set that
attribute using OPEN(create) with EXCLUSIVE4_1.

The FATTR4_WORD2_TIME_DELEG attributes are also not to be allowed
for OPEN(create) with EXCLUSIVE4_1. It doesn't make sense to set
a delegated timestamp on a new file.

Fixes: 7e13f4f8d27d ("nfsd: handle delegated timestamps in SETATTR")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfs4xdr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 51ef97c25456..8f12dee4c3b5 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3379,6 +3379,8 @@ static __be32 nfsd4_encode_fattr4_suppattr_exclcreat(struct xdr_stream *xdr,
 		supp[0] &= ~FATTR4_WORD0_ACL;
 	if (!args->contextsupport)
 		supp[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
+	supp[2] &= ~FATTR4_WORD2_TIME_DELEG_ACCESS;
+	supp[2] &= ~FATTR4_WORD2_TIME_DELEG_MODIFY;
 
 	supp[0] &= NFSD_SUPPATTR_EXCLCREAT_WORD0;
 	supp[1] &= NFSD_SUPPATTR_EXCLCREAT_WORD1;
-- 
2.51.0