nfsd: fix configuration of supported minor versions

When the user turns off all minor versions of NFSv4, that should be
equivalent to turning off NFSv4 support, so a mount attempt using NFSv4
should get RPC_PROG_MISMATCH, not NFSERR_MINOR_VERS_MISMATCH.

Allow the user to use either '4.0' or '4' to enable or disable minor
version 0.  Other minor versions are still enabled or disabled using the
'4.x' format.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

2 files changed, 22 insertions, 8 deletions

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index d54fb0e3f30e..4bbba88416dc 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -561,6 +561,7 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
                 len = qword_get(&mesg, vers, size);
                 if (len <= 0) return -EINVAL;
                 do {
+                        enum vers_op cmd;
                         sign = *vers;
                         if (sign == '+' || sign == '-')
                                 num = simple_strtol((vers+1), &minorp, 0);
@@ -571,21 +572,20 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
                                         return -EINVAL;
                                 if (kstrtouint(minorp+1, 0, &minor) < 0)
                                         return -EINVAL;
-                                if (nfsd_minorversion(minor, sign == '-' ?
-                                                     NFSD_CLEAR : NFSD_SET) < 0)
-                                        return -EINVAL;
-                                goto next;
-                        }
+                        } else
+                                minor = 0;
+                        cmd = sign == '-' ? NFSD_CLEAR : NFSD_SET;
                         switch(num) {
                         case 2:
                         case 3:
-                        case 4:
-                                nfsd_vers(num, sign == '-' ? NFSD_CLEAR : NFSD_SET);
+                                nfsd_vers(num, cmd);
                                 break;
+                        case 4:
+                                if (nfsd_minorversion(minor, cmd) >= 0)
+                                        break;
                         default:
                                 return -EINVAL;
                         }
-                next:
                         vers += len + 1;
                 } while ((len = qword_get(&mesg, vers, size)) > 0);
                 /* If all get turned off, turn them back on, as
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 2e378d0479ad..efd66da99201 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -153,6 +153,18 @@ int nfsd_vers(int vers, enum vers_op change)
         return 0;
 }
 
+static void
+nfsd_adjust_nfsd_versions4(void)
+{
+        unsigned i;
+
+        for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++) {
+                if (nfsd_supported_minorversions[i])
+                        return;
+        }
+        nfsd_vers(4, NFSD_CLEAR);
+}
+
 int nfsd_minorversion(u32 minorversion, enum vers_op change)
 {
         if (minorversion > NFSD_SUPPORTED_MINOR_VERSION)
@@ -160,9 +172,11 @@ int nfsd_minorversion(u32 minorversion, enum vers_op change)
         switch(change) {
         case NFSD_SET:
                 nfsd_supported_minorversions[minorversion] = true;
+                nfsd_vers(4, NFSD_SET);
                 break;
         case NFSD_CLEAR:
                 nfsd_supported_minorversions[minorversion] = false;
+                nfsd_adjust_nfsd_versions4();
                 break;
         case NFSD_TEST:
                 return nfsd_supported_minorversions[minorversion];