Merge pull request #753 from yast/backport/component_of

Backport BlkDevice#component_of

src/lib/y2storage/blk_device.rb

@@ -361,13 +361,44 @@ def direct_md
       descendants.detect { |dev| dev.is?(:md) && dev.devices.include?(self) }
     end
 
+    # DM arrays defined on top of the device
+    #
+    # @return [Array<DmRaid>] empty if the device is not used by any DM RAID
+    #   device
+    def dm_raids
+      children.select { |dev| dev.is?(:dm_raid) }
+    end
+
+    # Multipath device defined on top of the device
+    #
+    # @return [Multipath, nil] nil if the device is not part of any multipath
+    def multipath
+      children.find { |dev| dev.is?(:multipath) }
+    end
+
     # Whether the device forms part of an LVM or MD RAID
     #
     # @return [Boolean]
     def part_of_lvm_or_md?
       !lvm_pv.nil? || !md.nil?
     end
 
+    # Devices built on top of this device, to be used mainly by the Partitioner
+    # to display which devices are using this one as its base.
+    #
+    # This does not include all the descendants, but only those multi-device
+    # devices for which this is one of the components. For example, it will
+    # include any LVM VG for which this device is one of its physical volumes
+    # (directly or through an encryption) or any RAID having this device as
+    # one of its members.
+    #
+    # @return [Array<Device>] a collection of MD RAIDs, DM RAIDs, volume groups,
+    #   and multipath devices
+    def component_of
+      vg = lvm_pv ? lvm_pv.lvm_vg : nil
+      (dm_raids + [vg] + [md] + [multipath]).compact
+    end
+
     # Label of the filesystem, if any
     # @return [String, nil]
     def filesystem_label

test/y2storage/blk_device_test.rb

@@ -678,6 +678,103 @@
     end
   end
 
+  describe "#component_of" do
+    context "for a device not used in an LVM or in a RAID or in multipath" do
+      let(:scenario) { "mixed_disks" }
+      let(:device_name) { "/dev/sda1" }
+
+      it "returns an empty array" do
+        expect(device.component_of).to eq []
+      end
+    end
+
+    context "for a device that is part of several DM RAIDs" do
+      let(:scenario) { "empty-dm_raids.xml" }
+      let(:device_name) { "/dev/sdb" }
+
+      it "returns an array with all the corresponding DM RAIDs" do
+        expect(device.component_of.size).to eq 2
+        expect(device.component_of).to all(be_a(Y2Storage::DmRaid))
+        expect(device.component_of.map(&:name)).to contain_exactly(
+          "/dev/mapper/isw_ddgdcbibhd_test1", "/dev/mapper/isw_ddgdcbibhd_test2"
+        )
+      end
+    end
+
+    context "for a device directly used in an LVM" do
+      let(:scenario) { "complex-lvm-encrypt" }
+      let(:device_name) { "/dev/sde2" }
+
+      it "returns an array with the LVM VG" do
+        expect(device.component_of.size).to eq 1
+        expect(device.component_of.first).to be_a Y2Storage::LvmVg
+        expect(device.component_of.first.name).to eq "/dev/vg1"
+      end
+    end
+
+    context "for an encrypted device directly used in an LVM" do
+      let(:scenario) { "complex-lvm-encrypt" }
+      let(:device_name) { "/dev/sde1" }
+
+      it "returns an array with the LVM VG" do
+        expect(device.component_of.size).to eq 1
+        expect(device.component_of.first).to be_a Y2Storage::LvmVg
+        expect(device.component_of.first.name).to eq "/dev/vg0"
+      end
+    end
+
+    context "for a disk used indirectly (through its partitions) in an LVM" do
+      let(:scenario) { "complex-lvm-encrypt" }
+      let(:device_name) { "/dev/sde" }
+
+      it "returns an empty array" do
+        expect(device.component_of).to eq []
+      end
+    end
+
+    context "for a device directly used in an MD RAID" do
+      let(:scenario) { "subvolumes-and-empty-md.xml" }
+      let(:device_name) { "/dev/sda4" }
+
+      it "returns an array with the MD RAID" do
+        expect(device.component_of.size).to eq 1
+        expect(device.component_of.first).to be_a Y2Storage::Md
+        expect(device.component_of.first.name).to eq "/dev/md/strip0"
+      end
+    end
+
+    context "for an encrypted device directly used in an MD RAID" do
+      let(:scenario) { "subvolumes-and-empty-md.xml" }
+      let(:device_name) { "/dev/sda5" }
+
+      it "returns an array with the MD RAID" do
+        expect(device.component_of.size).to eq 1
+        expect(device.component_of.first).to be_a Y2Storage::Md
+        expect(device.component_of.first.name).to eq "/dev/md/strip0"
+      end
+    end
+
+    context "for a disk used indirectly (through its partitions) in an MD RAID" do
+      let(:scenario) { "subvolumes-and-empty-md.xml" }
+      let(:device_name) { "/dev/sda" }
+
+      it "returns an empty array" do
+        expect(device.component_of).to eq []
+      end
+    end
+
+    context "for a disk that is part of a multipath setup" do
+      let(:scenario) { "multipath-formatted.xml" }
+      let(:device_name) { "/dev/sda" }
+
+      it "returns an array with the multipath device" do
+        expect(device.component_of.size).to eq 1
+        expect(device.component_of.first).to be_a Y2Storage::Multipath
+        expect(device.component_of.first.name).to eq "/dev/mapper/0QEMU_QEMU_HARDDISK_mpath1"
+      end
+    end
+  end
+
   describe "#hwinfo" do
     let(:device_name) { "/dev/sda" }