Avoid udev interactions on RH7+ when creating partitions

If the partition created by parted happens to already contain some
metadata (like LVM signature), then the udev rules triggered by the
partition being created automatically kick off actions like activating
the logical volume. This change prevents such udev rules from
triggering until the contents are wiped.

This solution is still not ideal, but so far appears to work.

Author: gombasg

src/main/perl/Disk.pm

@@ -399,10 +399,9 @@ sub clearpart_ks
 
     print <<EOF;
 wipe_metadata $path 1
-
 parted $path -s -- mklabel $self->{label}
-
 rereadpt $path
+udevadm settle
 
 EOF
 }

src/main/perl/Partition.pm

@@ -627,6 +627,11 @@ sub create_pre_ks
     # make sure this never matches on anything else
     $extended_txt .= "_no_msdos_label" if ($self->{holding_dev}->{label} ne MSDOS);
 
+    # Avoid LVM/mdadm/etc. autodiscovery kicking in after the partition has
+    # been created
+    my $pause_udev = $self->{anaconda_version} >= ANACONDA_VERSION_EL_7_0 ? "udevadm control --stop-exec-queue" : "";
+    my $unpause_udev = $self->{anaconda_version} >= ANACONDA_VERSION_EL_7_0 ? "udevadm control --start-exec-queue" : "";
+
     print <<EOF;
 if ! grep -q '$self->{devname}\$' /proc/partitions
 then
@@ -673,26 +678,31 @@ EOF
     }
     print <<EOF;
     $end_txt
+    $pause_udev
     parted $disk -s -- u s mkpart $self->{type} \$begin \$end
+    while [ ! -e $path ]; do
+        sleep 1
+        udevadm settle --timeout=5
+    done
+    if [ "$self->{type}" != "$extended_txt" ]
+    then
+        wipe_metadata $path $clear_mb
+    fi
+    $unpause_udev
+    udevadm settle
 EOF
 
     my @flags = keys(%{$self->{flags}});
     if ( @flags > 0 ) {
         for my $flag (sort @flags) {
             my $value = $self->{flags}{$flag} ? "on" : "off";
-            print <<EOF;
-    parted $disk -s -- set $n $flag $value
-EOF
+            print "    parted $disk -s -- set $n $flag $value\n";
         }
+        # Call this once, after all flags have been set
+        print "    udevadm settle\n";
     }
 
     print <<EOF;
-    rereadpt $disk
-    if [ "$self->{type}" != "$extended_txt" ]
-    then
-        wipe_metadata $path $clear_mb
-    fi
-
     echo $path >> @{[PART_FILE]}
 fi
 EOF