storagedriver: Rework garbage collector logic

* remove move_to_trash()
* remove recover_from_trash()
* add exits() which say an image exists
* rework make_free_space()

storagedriver.py

 from disk import Disk
 from disk import Disk
 from storagecelery import celery
 from storagecelery import celery
-from os import path, unlink, statvfs, listdir, mkdir
-from shutil import move
+import os
+from os import path, unlink, statvfs, listdir
 from celery.contrib.abortable import AbortableTask
 from celery.contrib.abortable import AbortableTask
 import logging
 import logging
 
 
@@ -89,52 +89,24 @@ def get_storage_stat(path):
 
 
 
 
 @celery.task
 @celery.task
-def move_to_trash(datastore, disk_name):
-    ''' Move path to the trash directory.
-    '''
-    trash_path = path.join(datastore, trash_directory)
-    disk_path = path.join(datastore, disk_name)
-    if not path.isdir(trash_path):
-        mkdir(trash_path)
-    # TODO: trash dir configurable?
-    move(disk_path, trash_path)
+def exists(path, disk_name):
+    return os.path.exists(os.path.join(path, disk_name))
 
 
 
 
 @celery.task
 @celery.task
-def recover_from_trash(datastore, disk_name):
-    ''' Recover named disk from the trash directory.
-    '''
-    if path.exists(path.join(datastore, disk_name)):
-        return False
-    disk_path = path.join(datastore, trash_directory, disk_name)
-    # TODO: trash dir configurable?
-    move(disk_path, datastore)
-    return True
-
-
-@celery.task
-def make_free_space(datastore, percent=10):
+def make_free_space(path, deletable_disks, percent=10):
     ''' Check for free space on datastore.
     ''' Check for free space on datastore.
         If free space is less than the given percent
         If free space is less than the given percent
         removes oldest files to satisfy the given requirement.
         removes oldest files to satisfy the given requirement.
     '''
     '''
-    trash_path = path.join(datastore, trash_directory)
-
-    def comp(filename):
-        try:
-            return path.getctime(path.join(trash_path, filename))
-        except OSError:
-            return 0
-
-    files = sorted(listdir(trash_path), key=comp)
     logger.info("Free space on datastore: %s" %
     logger.info("Free space on datastore: %s" %
-                get_storage_stat(trash_path).get('free_percent'))
-    while get_storage_stat(trash_path).get('free_percent') < percent:
-        logger.debug(get_storage_stat(trash_path))
+                get_storage_stat(path).get('free_percent'))
+    while get_storage_stat(path).get('free_percent') < percent:
+        logger.debug(get_storage_stat(path))
         try:
         try:
-            f = files.pop(0)
-            unlink(path.join(trash_path, f))
+            f = deletable_disks.pop(0)
+            unlink(os.path.join(path, f))
             logger.info('Image: %s removed.' % f)
             logger.info('Image: %s removed.' % f)
         except IndexError:
         except IndexError:
-            raise Exception("Trash folder is empty.")
+            raise Exception("There is not deletable disk.")
     return True
     return True