[PATCH] kNFSd: ensure XDR buffer is large enough for NFSv4

This patch changes the 'xdrsize' parameter to svc_create(), to be
     NFS4_SVC_XDRSIZE   if v4 is defined
else NFS3_SVC_XDRSIZE   if v3 is defined
else NFS2_SVC_XDRSIZE     (formerly NFSSVC_XDRSIZE)

This always works, since
     NFS4_SVC_XDRSIZE >= NFS3_SVC_XDRSIZE >= NFS2_SVC_XDRSIZE.

The value of NFSD_BUFSIZE has also been moved to const.h, since we need
the definition available in nfs4proc.c

fs/nfsd/nfssvc.c

@@ -31,10 +31,11 @@
 #include <linux/nfsd/stats.h>
 #include <linux/nfsd/cache.h>
 #include <linux/nfsd/xdr.h>
+#include <linux/nfsd/xdr3.h>
+#include <linux/nfsd/xdr4.h>
 #include <linux/lockd/bind.h>
 
 #define NFSDDBG_FACILITY	NFSDDBG_SVC
-#define NFSD_BUFSIZE		(1024 + NFSSVC_MAXBLKSIZE)
 
 /* these signals will be delivered to an nfsd thread 
  * when handling a request

include/linux/nfsd/const.h

@@ -30,6 +30,16 @@
 # define NFS_SUPER_MAGIC	0x6969
 #endif
 
+#define NFSD_BUFSIZE		(1024 + NFSSVC_MAXBLKSIZE)
+
+#ifdef CONFIG_NFSD_V4
+# define NFSSVC_XDRSIZE		NFS4_SVC_XDRSIZE
+#elif defined(CONFIG_NFSD_V3)
+# define NFSSVC_XDRSIZE		NFS3_SVC_XDRSIZE
+#else
+# define NFSSVC_XDRSIZE		NFS2_SVC_XDRSIZE
+#endif
+
 #endif /* __KERNEL__ */
 
 #endif /* _LINUX_NFSD_CONST_H */

include/linux/nfsd/xdr.h

@@ -119,7 +119,7 @@ union nfsd_xdrstore {
 	struct nfsd_readdirargs	readdir;
 };
 
-#define NFSSVC_XDRSIZE		sizeof(union nfsd_xdrstore)
+#define NFS2_SVC_XDRSIZE	sizeof(union nfsd_xdrstore)
 
 
 int nfssvc_decode_void(struct svc_rqst *, u32 *, void *);