mgr/vol: support clone operation on subvol v3

Signed-off-by: Rishabh Dave <ridave@redhat.com>

diff --git a/src/pybind/mgr/volumes/fs/operations/versions/subvolume_v3.py b/src/pybind/mgr/volumes/fs/operations/versions/subvolume_v3.py
index 4d4a8dea66cd6286921e3dea827c45341f1b4bdc..eadd6c32ded35344dd425f0685acb3ac854c8007 100644 (file)
--- a/src/pybind/mgr/volumes/fs/operations/versions/subvolume_v3.py
+++ b/src/pybind/mgr/volumes/fs/operations/versions/subvolume_v3.py
@@ -257,3 +257,28 @@ class SubvolumeV3(SubvolumeV2):
             MetadataManager.GLOBAL_META_KEY_STATE,
             SubvolumeStates.STATE_RETAINED.value)
         self.metadata_mgr.flush()
+
+    # Following methods help clone operation -
+
+
+    def snapshot_data_path(self, snap_name):
+        snap_path = join(self.snapshot_path(snap_name), b'mnt')
+
+        # v2 raises exception if the snapshot path do not exist so do the same
+        # to prevent any bugs due to difference in behaviour.
+        #
+        # not raising exception indeed leads to a bug: the volumes plugin fails
+        # when exception is not raised by this method when it is called by
+        # do_clone() method of async_cloner.py. this is made to happen by a
+        # test by deleting snapshot after running the snapshot clone command
+        # but before the clone operation actually begins. this is done by
+        # adding a delay using mgr/volumes/snapshot_clone_delay config option.
+        try:
+            self.fs.stat(snap_path)
+        except cephfs.Error as e:
+            if e.errno == errno.ENOENT:
+                raise VolumeException(-errno.ENOENT,
+                                      f'snapshot \'{snap_name}\' does not exist')
+            raise VolumeException(-e.args[0], e.args[1])
+
+        return snap_path