B OpenNebula#3175 Updated new nbds_max method

src/vmm_mad/remotes/lib/lxd/mapper/qcow2.rb

@@ -23,6 +23,8 @@
 # Block device mapping for qcow2 disks, backed by nbd kernel module
 class Qcow2Mapper < Mapper
 
+    NBDS_MAX = 256 # Default nbd module param config provided by opennebula
+
     def do_map(one_vm, disk, _directory)
         device = nbd_device
 
@@ -66,17 +68,17 @@ def do_unmap(device, _one_vm, _disk, _directory)
     private
 
     # Detects Max number of block devices
-    def load_nbds_max
+    def nbds_max
         cmd = '/sbin/modprobe -c'
         rc, mods_conf, e = Command.execute(cmd, false)
 
         if !rc.zero?
-            OpenNebula.log_error("Cannot load max number of nbd devices\n#{e}")
-            return 0
+            OpenNebula.log_error("Cannot load max number of nbd devices\n#{e}"\
+                "Falling back to default #{NBDS_MAX}")
+            return NBDS_MAX
         end
 
-        param = mods_conf[/(nbds_max=)(\d+)/]
-        param.split('=').last.to_i
+        mods_conf.match(/(nbds_max=)(\d+)/)[-1].to_i
     end
 
     # Returns the first non-used nbd device
@@ -91,7 +93,7 @@ def nbd_device
             nbds << m[1].to_i
         end
 
-        load_nbds_max.times do |i|
+        nbds_max.times do |i|
             return "/dev/nbd#{i}" unless nbds.include?(i)
         end