nfsd: fix version-setting regression on old kernels
authorJ. Bruce Fields <bfields@citi.umich.edu>
Thu, 4 Feb 2010 22:03:53 +0000 (17:03 -0500)
committerSteve Dickson <steved@redhat.com>
Thu, 4 Feb 2010 22:04:33 +0000 (17:04 -0500)
/proc/fs/nfsd/versions was extended to allow turning on/off minor
versions by echoing "+4.1" or "-4.1" to /proc/fs/nsfd/versions.

Unfortunately, pre-2.6.30 kernels just stop parsing at first non-digit,
so "-4.1" is interpreted as "-4".  If new nfs-utils (on old kernel)
writes "+2", "+3", "+4", then "-4.1", result therefore is to turn off
4.1.

Given that historical behavior, it may have been a mistake to extend the
interface the way we did; but at this point we're probably stuck with
it.  So, just reverse the order we write versions in.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
utils/nfsd/nfssvc.c

index b8028bb..60232b8 100644 (file)
@@ -238,17 +238,17 @@ nfssvc_setvers(unsigned int ctlbits, int minorvers4)
        if (fd < 0)
                return;
 
+       n = minorvers4 >= 0 ? minorvers4 : -minorvers4;
+       if (n >= NFSD_MINMINORVERS4 && n <= NFSD_MAXMINORVERS4)
+                   off += snprintf(ptr+off, sizeof(buf) - off, "%c4.%d ",
+                                   minorvers4 > 0 ? '+' : '-',
+                                   n);
        for (n = NFSD_MINVERS; n <= NFSD_MAXVERS; n++) {
                if (NFSCTL_VERISSET(ctlbits, n))
                    off += snprintf(ptr+off, sizeof(buf) - off, "+%d ", n);
                else
                    off += snprintf(ptr+off, sizeof(buf) - off, "-%d ", n);
        }
-       n = minorvers4 >= 0 ? minorvers4 : -minorvers4;
-       if (n >= NFSD_MINMINORVERS4 && n <= NFSD_MAXMINORVERS4)
-                   off += snprintf(ptr+off, sizeof(buf) - off, "%c4.%d",
-                                   minorvers4 > 0 ? '+' : '-',
-                                   n);
        xlog(D_GENERAL, "Writing version string to kernel: %s", buf);
        snprintf(ptr+off, sizeof(buf) - off, "\n");
        if (write(fd, buf, strlen(buf)) != strlen(buf))