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>

4 files changed, 50 insertions, 4 deletions

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index db208dd8fdca..52bb14debb30 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -921,7 +921,7 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
          * According to RFC3010, this takes precedence over all other errors.
          */
         status = nfserr_minor_vers_mismatch;
-        if (args->minorversion > NFSD_SUPPORTED_MINOR_VERSION)
+        if (args->minorversion > nfsd_supported_minorversion)
                 goto out;
 
         if (!nfs41_op_ordering_ok(args)) {
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 4adebb6312c4..a9b8c75bf0bf 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -792,8 +792,9 @@ out_free:
 static ssize_t __write_versions(struct file *file, char *buf, size_t size)
 {
         char *mesg = buf;
-        char *vers, sign;
+        char *vers, *minorp, sign;
         int len, num;
+        unsigned minor;
         ssize_t tlen = 0;
         char *sep;
 
@@ -814,9 +815,20 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
                 do {
                         sign = *vers;
                         if (sign == '+' || sign == '-')
-                                num = simple_strtol((vers+1), NULL, 0);
+                                num = simple_strtol((vers+1), &minorp, 0);
                         else
-                                num = simple_strtol(vers, NULL, 0);
+                                num = simple_strtol(vers, &minorp, 0);
+                        if (*minorp == '.') {
+                                if (num < 4)
+                                        return -EINVAL;
+                                minor = simple_strtoul(minorp+1, NULL, 0);
+                                if (minor == 0)
+                                        return -EINVAL;
+                                if (nfsd_minorversion(minor, sign == '-' ?
+                                                     NFSD_CLEAR : NFSD_SET) < 0)
+                                        return -EINVAL;
+                                goto next;
+                        }
                         switch(num) {
                         case 2:
                         case 3:
@@ -826,6 +838,7 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
                         default:
                                 return -EINVAL;
                         }
+                next:
                         vers += len + 1;
                         tlen += len;
                 } while ((len = qword_get(&mesg, vers, size)) > 0);
@@ -844,6 +857,13 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
                                        num);
                         sep = " ";
                 }
+        if (nfsd_vers(4, NFSD_AVAIL))
+                for (minor = 1; minor <= NFSD_SUPPORTED_MINOR_VERSION; minor++)
+                        len += sprintf(buf+len, " %c4.%u",
+                                        (nfsd_vers(4, NFSD_TEST) &&
+                                         nfsd_minorversion(minor, NFSD_TEST)) ?
+                                                '+' : '-',
+                                        minor);
         len += sprintf(buf+len, "\n");
         return len;
 }
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
  */
diff --git a/include/linux/nfsd/nfsd.h b/include/linux/nfsd/nfsd.h
index 1f063d495159..70339b7b83c0 100644
--- a/include/linux/nfsd/nfsd.h
+++ b/include/linux/nfsd/nfsd.h
@@ -53,6 +53,7 @@ typedef int (*nfsd_dirop_t)(struct inode *, struct dentry *, int, int);
 extern struct svc_program       nfsd_program;
 extern struct svc_version       nfsd_version2, nfsd_version3,
                                 nfsd_version4;
+extern u32                      nfsd_supported_minorversion;
 extern struct mutex             nfsd_mutex;
 extern struct svc_serv          *nfsd_serv;
 
@@ -149,6 +150,7 @@ int nfsd_set_posix_acl(struct svc_fh *, int, struct posix_acl *);
 
 enum vers_op {NFSD_SET, NFSD_CLEAR, NFSD_TEST, NFSD_AVAIL };
 int nfsd_vers(int vers, enum vers_op change);
+int nfsd_minorversion(u32 minorversion, enum vers_op change);
 void nfsd_reset_versions(void);
 int nfsd_create_serv(void);