mgr/volumes: snapshot util module

Signed-off-by: Venky Shankar <vshankar@redhat.com>
(cherry picked from commit b30f0cb18543d7bcd9161b4e39d163425df19a27)

diff --git a/src/pybind/mgr/volumes/fs/operations/snapshot_util.py b/src/pybind/mgr/volumes/fs/operations/snapshot_util.py
new file mode 100644 (file)
index 0000000..2223c58
--- /dev/null
+++ b/src/pybind/mgr/volumes/fs/operations/snapshot_util.py
@@ -0,0 +1,30 @@
+import os
+import errno
+
+import cephfs
+
+from ..exception import VolumeException
+
+def mksnap(fs, snappath):
+    """
+    Create a snapshot, or do nothing if it already exists.
+    """
+    try:
+        # snap create does not accept mode -- use default
+        fs.mkdir(snappath, 0o755)
+    except cephfs.ObjectExists:
+        return
+    except cephfs.Error as e:
+        raise VolumeException(-e.args[0], e.args[1])
+
+def rmsnap(fs, snappath):
+    """
+    Remove a snapshot
+    """
+    try:
+        fs.stat(snappath)
+        fs.rmdir(snappath)
+    except cephfs.ObjectNotFound:
+        raise VolumeException(-errno.ENOENT, "snapshot '{0}' does not exist".format(os.path.basename(snappath)))
+    except cephfs.Error as e:
+        raise VolumeException(-e.args[0], e.args[1])