ceph-disk: guard partprobe with udevadm settle

Call udevadm settle before and after partprobe.

A side effect of partprobe is to remove partitions and add them again.
The first udevadm settle waits for ongoing udev events to complete, just
in case one of them rely on an existing partition on dev.

The second udevadm settle guarantees to the caller that all udev events
related to the partition table change have been processed, i.e. the
95-ceph-osd.rules actions and mode changes, group changes etc. are
complete.

Signed-off-by: Loic Dachary <ldachary@redhat.com>

diff --git a/src/ceph-disk b/src/ceph-disk
index e219d8a56679ce58b0135f0a3ea9acc9e3a3d1a8..27040d18ec33edf04bab089c6a4e356ef13c7e1e 100755 (executable)
--- a/src/ceph-disk
+++ b/src/ceph-disk
@@ -1207,14 +1207,21 @@ def get_free_partition_index(dev):
 
 
 def update_partition(dev, description):
-     LOG.debug('Calling partprobe on %s device %s', description, dev)
-     command(
-         [
-             'partprobe',
-             dev,
-         ],
-     )
-
+    """
+    Must be called after modifying a partition table so the kernel
+    know about the change and fire udev events accordingly. A side
+    effect of partprobe is to remove partitions and add them again.
+    The first udevadm settle waits for ongoing udev events to
+    complete, just in case one of them rely on an existing partition
+    on dev.  The second udevadm settle guarantees to the caller that
+    all udev events related to the partition table change have been
+    processed, i.e. the 95-ceph-osd.rules actions and mode changes,
+    group changes etc. are complete.
+    """
+    LOG.debug('Calling partprobe on %s device %s', description, dev)
+    command_check_call(['udevadm', 'settle'])
+    command_check_call(['partprobe', dev])
+    command_check_call(['udevadm', 'settle'])
 
 def zap(dev):
     """
@@ -1374,14 +1381,6 @@ def prepare_journal_dev(
 
         update_partition(journal, 'prepared')
 
-        # wait for udev event queue to clear
-        command(
-            [
-                'udevadm',
-                'settle',
-                ],
-            )
-
         LOG.debug('Journal is GPT partition %s', journal_symlink)
 
         if journal_dm_keypath:
@@ -1593,13 +1592,6 @@ def prepare_dev(
                 ],
             )
             update_partition(data, 'created')
-            command(
-                [
-                    # wait for udev event queue to clear
-                    'udevadm',
-                    'settle',
-                    ],
-                )
         except subprocess.CalledProcessError as e:
             raise Error(e)