nfsd41: control nfsv4.1 svc via /proc/fs/nfsd/versions

Support enabling and disabling nfsv4.1 via /proc/fs/nfsd/versions
by writing the strings "+4.1" or "-4.1" correspondingly.

Use user mode nfs-utils (rpc.nfsd option) to enable.
This will allow us to get rid of CONFIG_NFSD_V4_1

[nfsd41: disable support for minorversion by default]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 24 insertions, 0 deletions

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index b53a098e97a4..e9d57734a348 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -121,6 +121,8 @@ struct svc_program		nfsd_program = {
 
 };
 
+u32 nfsd_supported_minorversion;
+
 int nfsd_vers(int vers, enum vers_op change)
 {
         if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
@@ -147,6 +149,28 @@ int nfsd_vers(int vers, enum vers_op change)
         }
         return 0;
 }
+
+int nfsd_minorversion(u32 minorversion, enum vers_op change)
+{
+        if (minorversion > NFSD_SUPPORTED_MINOR_VERSION)
+                return -1;
+        switch(change) {
+        case NFSD_SET:
+                nfsd_supported_minorversion = minorversion;
+                break;
+        case NFSD_CLEAR:
+                if (minorversion == 0)
+                        return -1;
+                nfsd_supported_minorversion = minorversion - 1;
+                break;
+        case NFSD_TEST:
+                return minorversion <= nfsd_supported_minorversion;
+        case NFSD_AVAIL:
+                return minorversion <= NFSD_SUPPORTED_MINOR_VERSION;
+        }
+        return 0;
+}
+
 /*
  * Maximum number of nfsd processes
  */