nfsd: Fix up the "supattr_exclcreat" attributes

If an NFSv4 client asks us for the supattr_exclcreat, then we must
not return attributes that are unsupported by this minor version.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Fixes: 75976de6 ("NFSD: Return word2 bitmask if setting security..,")
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4xdr.c

@@ -2831,9 +2831,14 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	}
 #endif /* CONFIG_NFSD_PNFS */
 	if (bmval2 & FATTR4_WORD2_SUPPATTR_EXCLCREAT) {
-		status = nfsd4_encode_bitmap(xdr, NFSD_SUPPATTR_EXCLCREAT_WORD0,
-						  NFSD_SUPPATTR_EXCLCREAT_WORD1,
-						  NFSD_SUPPATTR_EXCLCREAT_WORD2);
+		u32 supp[3];
+
+		memcpy(supp, nfsd_suppattrs[minorversion], sizeof(supp));
+		supp[0] &= NFSD_SUPPATTR_EXCLCREAT_WORD0;
+		supp[1] &= NFSD_SUPPATTR_EXCLCREAT_WORD1;
+		supp[2] &= NFSD_SUPPATTR_EXCLCREAT_WORD2;
+
+		status = nfsd4_encode_bitmap(xdr, supp[0], supp[1], supp[2]);
 		if (status)
 			goto out;
 	}