utils/nfsd: add support for minorvers4

minorvers4 can be used to either enable or disable nfsv4.x.

If minorvers4 is a positive integer n, in the allowed range (only
minorversion 1 is supported for now), the string "+4.n" is appended
to the versions string written onto /proc/fs/nfsd/versions.

Correspondingly, if minorver4 is a negative integer -n, the string
"-4.n" is written.

With the default value, minorvers4==0, the minor version
setting is not changed.

Note that unlike the protocol versions 2, 3, or 4.  The minor version
setting controls the *maximum* minor version nfsd supports.  Particular
minor version cannot be controlled on their own.  With only minor
version 1 supported at the moment the difference doesn't matter,
but for future minor versions greater than 1, enabling minor
version X will enable support for all minor versions 1 through X.
Disabling minor version X will disable support for minor
versions X and up, enabling 1 through X-1.

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/support/include/nfs/nfs.h b/support/include/nfs/nfs.h
index fc26f4e..00b0028 100644
--- a/support/include/nfs/nfs.h
+++ b/support/include/nfs/nfs.h
@@ -13,6 +13,9 @@
 #define NFSD_MINVERS 2
 #define NFSD_MAXVERS 4
 
+#define NFSD_MINMINORVERS4 1
+#define NFSD_MAXMINORVERS4 1
+
 struct nfs_fh_len {
 	int		fh_size;
 	u_int8_t	fh_handle[NFS3_FHSIZE];