[pve-devel] [PATCH storage] fix: check connection for nfs v4 only server

[Alwin Antreich <a.antreich@proxmox.com>]

the check_connection is done by querying the exports of the nfs server
in question. With nfs v4 those exports aren't listed anymore since nfs
v4 employs a pseudo-filesystem starting from root (/).

rpcinfo allows to query the existence of an nfs v4 service.

Signed-off-by: Alwin Antreich <a.antreich@proxmox.com>
---
Note: scan_nfs will not work with nfs v4 only, since it also employs
      showmount. The path has to be provided manually.

 PVE/Storage/NFSPlugin.pm | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/PVE/Storage/NFSPlugin.pm b/PVE/Storage/NFSPlugin.pm
index e8e27c0..72e06c2 100644
--- a/PVE/Storage/NFSPlugin.pm
+++ b/PVE/Storage/NFSPlugin.pm
@@ -160,8 +160,16 @@ sub check_connection {
     my ($class, $storeid, $scfg) = @_;
 
     my $server = $scfg->{server};
-
-    my $cmd = ['/sbin/showmount', '--no-headers', '--exports', $server];
+    my $opts = $scfg->{options};
+
+    my $cmd;
+    if (defined($opts) && $opts =~ /vers=4.*/) {
+	# nfsv4 uses a pseudo-filesystem always beginning with /
+	# no exports are listed
+	$cmd = ['/usr/sbin/rpcinfo', '-t', $server, 'nfs', '4'];
+    } else {
+	$cmd = ['/sbin/showmount', '--no-headers', '--exports', $server];
+    }
 
     eval { run_command($cmd, timeout => 10, outfunc => sub {}, errfunc => sub {}) };
     if (my $err = $@) {
-- 
2.27.0