NFSv4.1: deprecate headerpadsz in CREATE_SESSION

We don't support header padding yet so better off ditching it
Reported-by: NSid Moore <learnmost@gmail.com>
Signed-off-by: NBenny Halevy <benny@tonian.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4proc.c

@@ -5098,7 +5098,6 @@ static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args)
 	if (mxresp_sz == 0)
 		mxresp_sz = NFS_MAX_FILE_IO_SIZE;
 	/* Fore channel attributes */
-	args->fc_attrs.headerpadsz = 0;
 	args->fc_attrs.max_rqst_sz = mxrqst_sz;
 	args->fc_attrs.max_resp_sz = mxresp_sz;
 	args->fc_attrs.max_ops = NFS4_MAX_OPS;
@@ -5111,7 +5110,6 @@ static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args)
 		args->fc_attrs.max_ops, args->fc_attrs.max_reqs);
 
 	/* Back channel attributes */
-	args->bc_attrs.headerpadsz = 0;
 	args->bc_attrs.max_rqst_sz = PAGE_SIZE;
 	args->bc_attrs.max_resp_sz = PAGE_SIZE;
 	args->bc_attrs.max_resp_sz_cached = 0;
@@ -5131,8 +5129,6 @@ static int nfs4_verify_fore_channel_attrs(struct nfs41_create_session_args *args
 	struct nfs4_channel_attrs *sent = &args->fc_attrs;
 	struct nfs4_channel_attrs *rcvd = &session->fc_attrs;
 
-	if (rcvd->headerpadsz > sent->headerpadsz)
-		return -EINVAL;
 	if (rcvd->max_resp_sz > sent->max_resp_sz)
 		return -EINVAL;
 	/*

fs/nfs/nfs4xdr.c

@@ -1725,7 +1725,7 @@ static void encode_create_session(struct xdr_stream *xdr,
 	*p++ = cpu_to_be32(args->flags);			/*flags */
 
 	/* Fore Channel */
-	*p++ = cpu_to_be32(args->fc_attrs.headerpadsz);	/* header padding size */
+	*p++ = cpu_to_be32(0);				/* header padding size */
 	*p++ = cpu_to_be32(args->fc_attrs.max_rqst_sz);	/* max req size */
 	*p++ = cpu_to_be32(args->fc_attrs.max_resp_sz);	/* max resp size */
 	*p++ = cpu_to_be32(max_resp_sz_cached);		/* Max resp sz cached */
@@ -1734,7 +1734,7 @@ static void encode_create_session(struct xdr_stream *xdr,
 	*p++ = cpu_to_be32(0);				/* rdmachannel_attrs */
 
 	/* Back Channel */
-	*p++ = cpu_to_be32(args->fc_attrs.headerpadsz);	/* header padding size */
+	*p++ = cpu_to_be32(0);				/* header padding size */
 	*p++ = cpu_to_be32(args->bc_attrs.max_rqst_sz);	/* max req size */
 	*p++ = cpu_to_be32(args->bc_attrs.max_resp_sz);	/* max resp size */
 	*p++ = cpu_to_be32(args->bc_attrs.max_resp_sz_cached);	/* Max resp sz cached */
@@ -4997,12 +4997,14 @@ static int decode_chan_attrs(struct xdr_stream *xdr,
 			     struct nfs4_channel_attrs *attrs)
 {
 	__be32 *p;
-	u32 nr_attrs;
+	u32 nr_attrs, val;
 
 	p = xdr_inline_decode(xdr, 28);
 	if (unlikely(!p))
 		goto out_overflow;
-	attrs->headerpadsz = be32_to_cpup(p++);
+	val = be32_to_cpup(p++);	/* headerpadsz */
+	if (val)
+		return -EINVAL;		/* no support for header padding yet */
 	attrs->max_rqst_sz = be32_to_cpup(p++);
 	attrs->max_resp_sz = be32_to_cpup(p++);
 	attrs->max_resp_sz_cached = be32_to_cpup(p++);

include/linux/nfs_xdr.h

@@ -158,7 +158,6 @@ struct nfs_seqid;
 
 /* nfs41 sessions channel attributes */
 struct nfs4_channel_attrs {
-	u32			headerpadsz;
 	u32			max_rqst_sz;
 	u32			max_resp_sz;
 	u32			max_resp_sz_cached;