Package: nfs-common
Version: 1:1.2.2-4squeeze2
Tags: patch

Assume the following:

An NFS server supports only NFS version <4.
This server is unreachable at a certain time.
A Debian client boots and tries to mount a directory on the server with
the 'bg' option, but without the 'nfsvers' option.
Later, the NFS server comes up.

Result: The client does _not_ mount the directory and the background
mount is silently terminated. This typically breaks cross-mounted
server scenarios.

[Note that specifying 'nfsvers=3' is NOT a workaround, because then
failing to connect the portmapper already terminates the mount.nfs
process and no backgrounding happens at all. This is a separate
bug IMHO.]

Analysis: When first trying an NFSv4 mount, 'vers=4' is appended
to the extra_options string in the mount options. Then, the next
(background) attempt also happens with vers=4 and consequently,
nfs_try_mount_v3v2() is never called. The mount fails, even though
the V3 server would now be reachable.

Fix appended. It looks like this bug is also present in current
Debian nfs-utils git.

Regards,
Wolfram.

--- nfs-utils-1.2.2/utils/mount/stropts.c 2012-10-10 23:12:14.000000000 +0200
+++ nfs-utils-1.2.2wg/utils/mount/stropts.c 2012-10-10 23:12:26.000000000 +0200
@@ -659,6 +659,7 @@
{
struct mount_options *options = po_dup(mi->options);
int result = 0;
+ char *extra_opts = NULL;

if (!options) {
errno = ENOMEM;
@@ -694,20 +695,26 @@
goto out_fail;
}

- /*
- * Update option string to be recorded in /etc/mtab.
- */
- if (po_join(options, mi->extra_opts) == PO_FAILED) {
+ if (po_join(options, &extra_opts) == PO_FAILED) {
errno = ENOMEM;
goto out_fail;
}

if (verbose)
printf(_("%s: trying text-based options '%s'
"),
- progname, *mi->extra_opts);
+ progname, extra_opts);

result = nfs_sys_mount(mi, options);

+ /*
+ * If success, update option string to be recorded in /etc/mtab.
+ */
+ if (result) {
+ free(*mi->extra_opts);
+ *mi->extra_opts = extra_opts;
+ } else
+ free(extra_opts);
+
out_fail:
po_destroy(options);
return result;


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