nfsd41: Backchannel: minorversion support for the back channel

Prepare to share backchannel code with NFSv4.1.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
[nfsd41: use nfsd4_cb_sequence for callback minorversion]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

fs/nfsd/nfs4callback.c

@@ -141,6 +141,7 @@ struct nfs4_cb_compound_hdr {
 	u32		ident;
 	u32		nops;
 	__be32		*nops_p;
+	u32		minorversion;
 	u32		taglen;
 	char		*tag;
 };
@@ -209,7 +210,7 @@ encode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr)
 
 	RESERVE_SPACE(16);
 	WRITE32(0);            /* tag length is always 0 */
-	WRITE32(NFS4_MINOR_VERSION);
+	WRITE32(hdr->minorversion);
 	WRITE32(hdr->ident);
 	hdr->nops_p = p;
 	WRITE32(hdr->nops);

fs/nfsd/nfs4state.c

@@ -984,6 +984,7 @@ gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se)
 	if ( !(parse_ipv4(se->se_callback_addr_len, se->se_callback_addr_val,
 	                 &cb->cb_addr, &cb->cb_port)))
 		goto out_err;
+	cb->cb_minorversion = 0;
 	cb->cb_prog = se->se_callback_prog;
 	cb->cb_ident = se->se_callback_ident;
 	return;

include/linux/nfsd/state.h

@@ -85,7 +85,8 @@ struct nfs4_cb_conn {
 	u32                     cb_addr;
 	unsigned short          cb_port;
 	u32                     cb_prog;
-	u32                     cb_ident;
+	u32			cb_minorversion;
+	u32                     cb_ident;	/* minorversion 0 only */
 	/* RPC client info */
 	atomic_t		cb_set;     /* successful CB_NULL call */
 	struct rpc_clnt *       cb_client;