Merge pull request #486 from ancorgs/resize_info

More object-oriented handling of partitions resizing

package/yast2-storage-ng.changes

@@ -1,3 +1,12 @@
+-------------------------------------------------------------------
+Mon Jan 15 12:51:01 UTC 2018 - ancor@suse.com
+
+- Some code reorganization regarding alignment and resizing.
+- Added to several places in the API the possibilty of using other
+  alignment types, in addition to the optimal one.
+- Added a (temporary) workaround to a possible bug in libstorage-ng
+  regarding alignment.
+
 -------------------------------------------------------------------
 Tue Jan  9 15:36:15 UTC 2018 - lslezak@suse.cz
 

src/lib/y2partitioner/actions/resize_partition.rb

@@ -39,7 +39,6 @@ def initialize(partition)
         textdomain "storage"
 
         @partition = partition
-        @resize_info = partition.detect_resize_info
         UIState.instance.select_row(partition)
       end
 
@@ -59,15 +58,18 @@ def run
       # @return [Y2Storage::Partition] partition to resize
       attr_reader :partition
 
+      # Resize information of the partition to be resized
+      #
       # @return [Y2Storage::ResizeInfo]
-      attr_reader :resize_info
+      def resize_info
+        partition.resize_info
+      end
 
       # Runs the dialog to resize the partition
       #
       # @return [Symbol] :finish if the dialog returns :next; dialog result otherwise.
       def resize
-        result = Dialogs::PartitionResize.run(partition, resize_info)
-        fix_end_alignment
+        result = Dialogs::PartitionResize.run(partition)
 
         result == :next ? :finish : result
       end
@@ -91,44 +93,6 @@ def validate
 
         false
       end
-
-      # After the partition's size was changed during resizing, make sure the
-      # new size meets all alignment requirements, but is still between
-      # min_size and max_size.
-      #
-      # @note This may change the partition's size (and region).
-      def fix_end_alignment
-        return if partition.nil? || partition.end_aligned?
-
-        ptable = partition.partition_table
-        region = ptable.align(partition.region, Y2Storage::AlignPolicy::ALIGN_END)
-        min_blocks = (resize_info.min_size.to_i / region.block_size.to_i)
-        max_blocks = (resize_info.max_size.to_i / region.block_size.to_i)
-        grain_blocks = (ptable.align_grain.to_i / region.block_size.to_i)
-
-        partition.region = fix_region_end(region, min_blocks, max_blocks, grain_blocks)
-      end
-
-      # Make sure a region's end is between min_blocks and max_blocks. If it
-      # is not, add or subtract blocks in grain_blocks increments. All sizes
-      # are specified in that region's block size.
-      #
-      # @note region parameter could be modified.
-      #
-      # @param region [Y2Storage::Region]
-      # @param min [Integer]
-      # @param max [Integer]
-      # @param grain [Integer]
-      #
-      # @return [Y2Storage::Region] adjusted region
-      def fix_region_end(region, min, max, grain)
-        if region.length < min
-          region.adjust_length(grain * ((min.to_f - region.length) / grain).ceil)
-        elsif region.length > max
-          region.adjust_length(grain * ((max.to_f - region.length) / grain).floor)
-        end
-        region
-      end
     end
   end
 end

src/lib/y2partitioner/dialogs/partition_resize.rb

@@ -15,12 +15,10 @@ class PartitionResize < CWM::Dialog
       # Constructor
       #
       # @param partition [Y2Storage::Partition] partition to resize
-      # @param resize_info [Y2Storage::ResizeInfo] partition resize info
-      def initialize(partition, resize_info)
+      def initialize(partition)
         textdomain "storage"
 
         @partition = partition
-        @resize_info = resize_info
         detect_space_info
       end
 
@@ -34,7 +32,7 @@ def title
       def contents
         HVSquash(
           VBox(
-            SizeSelector.new(partition, resize_info),
+            SizeSelector.new(partition),
             size_info
           )
         )
@@ -60,9 +58,6 @@ def should_open_dialog?
       # @return [Y2Storage::Partition]
       attr_reader :partition
 
-      # @return [Y2Storage::ResizeInfo]
-      attr_reader :resize_info
-
       # @return [Y2Storage::SpaceInfo]
       attr_reader :space_info
 
@@ -139,12 +134,10 @@ class SizeSelector < Widgets::ControllerRadioButtons
         # Constructor
         #
         # @param partition [Y2Storage::Partition]
-        # @param resize_info [Y2Storage::ResizeInfo]
-        def initialize(partition, resize_info)
+        def initialize(partition)
           textdomain "storage"
 
           @partition = partition
-          @resize_info = resize_info
         end
 
         # @macro seeAbstractWidget
@@ -182,7 +175,7 @@ def init
         # @macro seeAbstractWidget
         # Updates the partition with the new size
         def store
-          partition.size = current_widget.size
+          partition.resize(current_widget.size)
         end
 
         # @macro seeAbstractWidget
@@ -220,8 +213,12 @@ def validate
         # @return [Y2Storage::Partition]
         attr_reader :partition
 
+        # Resize information of the partition to be resized
+        #
         # @return [Y2Storage::ResizeInfo]
-        attr_reader :resize_info
+        def resize_info
+          partition.resize_info
+        end
 
         # Min possible size
         #

src/lib/y2storage/align_type.rb

@@ -24,6 +24,10 @@
 module Y2Storage
   # Class to represent all the possible align types implemented by libstorage
   #
+  # AlignType::REQUIRED can be used to align only to hard requirements.
+  # AlignType::OPTIMAL implies aligning to both hard requirements and topology
+  #   information, which optimizes performance.
+  #
   # This is a wrapper for the Storage::AlignType enum
   class AlignType
     include StorageEnumWrapper

src/lib/y2storage/blk_device.rb

@@ -397,5 +397,17 @@ def basename
     def hwinfo
       Y2Storage::HWInfoReader.instance.for_device(name)
     end
+
+    # Size of the space that could be theoretically reclaimed by shrinking the
+    # device
+    #
+    # It does not guarantee the new free space can really be used. Other
+    # restrictions (like alignment or the max number of partitions) may apply.
+    #
+    # @return [DiskSize]
+    def recoverable_size
+      return DiskSize.zero unless resize_info.resize_ok?
+      size - resize_info.min_size
+    end
   end
 end

src/lib/y2storage/device.rb

@@ -116,6 +116,13 @@ class Device
     #   If the device has any children, they are also taken into account;
     #   the result of this method is the combined information about this device
     #   and all its children.
+    #
+    #   Note that the minimal and maximal are not aligned.
+    #
+    #   If the device already exists on the disk (i.e., in the probed
+    #   devicegraph), this operation can be expensive. Thus, consider using
+    #   {#resize_info} or any other caching mechanism.
+    #
     #   @see can_resize?
     #
     #   @return [ResizeInfo]
@@ -206,6 +213,37 @@ def potential_orphans
       []
     end
 
+    # Information about the possibility of resizing a given device.
+    #
+    # This method relies on {#detect_resize_info}, caching the result for the
+    # whole lifecycle of this object.
+    #
+    # Take into account that the lifecycle of a Y2Storage::Device object is
+    # usually sorter than the one of its corresponding libstorage-ng C++ object.
+    # Due to the nature of SWIG, every query to the devicegraph will return a
+    # new Y2Storage::Device object. This is actually convenient in this case to
+    # control the lifetime of the caching.
+    #
+    # @example Caching the #detect_resize_info result
+    #
+    #   partition1 = disk.partitions.first
+    #
+    #   partition1.resize_info  # This calls #detect_resize_info
+    #   @same_part = partition1
+    #   @same_part.resize_info # Don't call #detect_resize_info, use cached
+    #
+    #  disk.partitions.first.resize_info # This calls #detect_resize_info
+    #    # because disk.partitions.first returns a new object representing
+    #    # the same device than partition1 (but not the same object).
+    #
+    #  @see #detect_resize_info
+    def resize_info
+      @resize_info ||= begin
+        log.info "Calling #detect_resize_info"
+        detect_resize_info
+      end
+    end
+
     # Check if the device can be resized.
     #
     # If the device has any children, they are also taken into account;
@@ -218,7 +256,7 @@ def potential_orphans
     #
     # @return [Boolean] true if the device can be resized, false if not.
     def can_resize?
-      detect_resize_info.resize_ok?
+      resize_info.resize_ok?
     end
 
     # Checks whether the device is a concrete kind(s) of device.