NFSD: Update GETATTR3args decoder to use struct xdr_stream

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs3proc.c

@@ -683,7 +683,6 @@ out:
  * NFSv3 Server procedures.
  * Only the results of non-idempotent operations are cached.
  */
-#define nfs3svc_decode_fhandleargs	nfs3svc_decode_fhandle
 #define nfs3svc_encode_attrstatres	nfs3svc_encode_attrstat
 #define nfs3svc_encode_wccstatres	nfs3svc_encode_wccstat
 #define nfsd3_mkdirargs			nfsd3_createargs
@@ -715,7 +714,7 @@ static const struct svc_procedure nfsd_procedures3[22] = {
 		.pc_decode = nfs3svc_decode_fhandleargs,
 		.pc_encode = nfs3svc_encode_attrstatres,
 		.pc_release = nfs3svc_release_fhandle,
-		.pc_argsize = sizeof(struct nfsd3_fhandleargs),
+		.pc_argsize = sizeof(struct nfsd_fhandle),
 		.pc_ressize = sizeof(struct nfsd3_attrstatres),
 		.pc_cachetype = RC_NOCACHE,
 		.pc_xdrressize = ST+AT,

fs/nfsd/nfs3xdr.c

@@ -29,8 +29,9 @@ static u32	nfs3_ftypes[] = {
 
 
 /*
- * XDR functions for basic NFS types
+ * Basic NFSv3 data types (RFC 1813 Sections 2.5 and 2.6)
  */
+
 static __be32 *
 encode_time3(__be32 *p, struct timespec64 *time)
 {
@@ -46,6 +47,26 @@ decode_time3(__be32 *p, struct timespec64 *time)
 	return p;
 }
 
+static bool
+svcxdr_decode_nfs_fh3(struct xdr_stream *xdr, struct svc_fh *fhp)
+{
+	__be32 *p;
+	u32 size;
+
+	if (xdr_stream_decode_u32(xdr, &size) < 0)
+		return false;
+	if (size == 0 || size > NFS3_FHSIZE)
+		return false;
+	p = xdr_inline_decode(xdr, size);
+	if (!p)
+		return false;
+	fh_init(fhp, NFS3_FHSIZE);
+	fhp->fh_handle.fh_size = size;
+	memcpy(&fhp->fh_handle.fh_base, p, size);
+
+	return true;
+}
+
 static __be32 *
 decode_fh(__be32 *p, struct svc_fh *fhp)
 {
@@ -312,14 +333,12 @@ void fill_post_wcc(struct svc_fh *fhp)
  */
 
 int
-nfs3svc_decode_fhandle(struct svc_rqst *rqstp, __be32 *p)
+nfs3svc_decode_fhandleargs(struct svc_rqst *rqstp, __be32 *p)
 {
+	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
 	struct nfsd_fhandle *args = rqstp->rq_argp;
 
-	p = decode_fh(p, &args->fh);
-	if (!p)
-		return 0;
-	return xdr_argsize_check(rqstp, p);
+	return svcxdr_decode_nfs_fh3(xdr, &args->fh);
 }
 
 int

fs/nfsd/xdr3.h

@@ -273,7 +273,7 @@ union nfsd3_xdrstore {
 
 #define NFS3_SVC_XDRSIZE		sizeof(union nfsd3_xdrstore)
 
-int nfs3svc_decode_fhandle(struct svc_rqst *, __be32 *);
+int nfs3svc_decode_fhandleargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_sattrargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_diropargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_accessargs(struct svc_rqst *, __be32 *);