Pass --yes to lvcreate only if LVM version is 2.02.99 or higher

Fixes regression introduced with 4.5 by the fix for #754517. The
regression has been reported upstream at
http://xen-tools.org/pipermail/xen-tools-discuss/2015-January/001079.html

Uses Sort::Versions for that. So add a new (build-)dependency on
libsort-versions-perl in the Debian package.

KNOWN_BUGS.markdown

@@ -1,16 +1,6 @@
 KNOWN BUGS in xen-tools
 =======================
 
-Bugs to fix before next release
--------------------------------
-
-* Older versions of LVM don't understand `--yes` while newer versions
-  require it. The fix for the latter
-  ([Debian bug report 754517](https://bugs.debian.org/754517))
-  introduced a regression with older LVM versions, e.g. on Debian 7
-  Wheezy. There's likely an LVM version check and an according switch
-  necessary.
-
 Bugs to fix rather soon
 -----------------------
 

bin/xen-create-image

@@ -806,6 +806,7 @@ use Data::Validate::IP qw/ is_ipv4 /;
 use Data::Validate::Domain qw/ is_hostname /;
 use Term::UI;
 use Term::ReadLine;
+use Sort::Versions;
 use Xen::Tools::Common;
 
 
@@ -3047,6 +3048,31 @@ sub createLVMBits
         }
     }
 
+    #
+    # For the calls to lvcreate below, we first need to check for the
+    # version of LVM running as their have been incompatible API
+    # changes somewhere between "2.02.95(2) (2012-03-06)" in Debian 7
+    # Wheezy and "2.02.111(2) (2014-09-01)" in Debian 8 Jessie. *sigh*
+    #
+    # See https://bugs.debian.org/754517
+    #
+    # I currently assume that all LVM version starting with 2.02.99
+    # should be fine with passing --yes as that version has an
+    # upstream changelog entry "Accept --yes in all commands so test
+    # scripts can be simpler".
+    #
+    # Assumes --yes is necessary if the LVM version can't be parsed.
+
+    my $lvm_needs_yes = 1;
+    my $lvm_version_output = `lvm version`;
+    if ($lvm_version_output =~ /^\s*LVM\s*version:\s*(\d[.\d]*)[\s(]/) {
+        my $lvm_version = $1;
+        my $no_yes_below_version = '2.02.99';
+
+        $lvm_needs_yes =
+            versioncmp($lvm_version, $no_yes_below_version) >= 0;
+    }
+
     foreach my $partition (@PARTITIONS)
     {
         my $disk     = $CONFIG{ 'hostname' } . '-' . $partition->{ 'name' };
@@ -3062,7 +3088,9 @@ sub createLVMBits
         # The commands to create the volume.
         #
         my $disk_cmd =
-          "lvcreate $CONFIG{'lvm'} --yes -L $partition->{'size'} -n $disk";
+          "lvcreate $CONFIG{'lvm'} ".
+          ($lvm_needs_yes ? '--yes' : '').
+          " -L $partition->{'size'} -n $disk";
 
         #
         # Create the volume

debian/changelog

@@ -29,6 +29,9 @@ xen-tools (4.5+dev-1) UNRELEASED; urgency=medium
     + Split off hardcoded release code names list and default mirrors in
       xen-create-image into separate configuration file which are parsed
       before the default settings or command-line options are set.
+    + Pass --yes to lvcreate only if LVM version is 2.02.99 or
+      higher. Fixes regression introduced with 4.5 by the fix for #754517.
+      - Add new (build-)dependency on libsort-versions-perl.
   * Update Vcs-* headers as Gitorious will close its doors in June.
   * Recommend debian-archive-keyring (for installing Debian DomUs on
     derivatives) and ubuntu-archive-keyring (for installing Ubuntu DomUs

debian/control

@@ -12,6 +12,7 @@ Build-Depends: debhelper (>= 9~),
                libfile-which-perl,
                liblog-message-perl | perl (<< 5.17.0),
                libterm-ui-perl | perl (<< 5.17.0),
+               libsort-versions-perl,
                libtest-notabs-perl,
                libtest-pod-coverage-perl,
                libtest-pod-perl,
@@ -30,6 +31,7 @@ Depends: debootstrap | cdebootstrap,
          libdata-validate-uri-perl,
          libfile-slurp-perl,
          libfile-which-perl,
+         libsort-versions-perl,
          libterm-ui-perl | perl (<< 5.17.0),
          libtext-template-perl,
          openssh-client,