From fc1dc9d77ea15e8dc07199d9f361ce13f62810d7 Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Tue, 6 Nov 2007 17:00:38 +0000
Subject: [PATCH] Allow DRBD8 operation without backing storage
This patch adds the following functionality:
- DRBD8 devices can assemble without local storage (done by allowing
None in the list of children, and making DRBD8 to ignore all
children if any is None)
- DRBD8 devices can attach (i.e. identify a device) which is not
connected to backing storage but to the correct network ports; this
is a rare case in normal operation (it's what would happen if one
manually detaches the local disk, and the backing LV still exists)
Reviewed-by: imsnah
---
lib/backend.py | 14 +++++++++++++-
lib/bdev.py | 8 +++++++-
lib/objects.py | 16 ++++++++++++++++
3 files changed, 36 insertions(+), 2 deletions(-)
diff --git a/lib/backend.py b/lib/backend.py
index 479cea256..f85ecba95 100644
--- a/lib/backend.py
+++ b/lib/backend.py
@@ -722,8 +722,20 @@ def _RecursiveAssembleBD(disk, owner, as_primary):
"""
children = []
if disk.children:
+ mcn = disk.ChildrenNeeded()
+ if mcn == -1:
+ mcn = 0 # max number of Nones allowed
+ else:
+ mcn = len(disk.children) - mcn # max number of Nones
for chld_disk in disk.children:
- children.append(_RecursiveAssembleBD(chld_disk, owner, as_primary))
+ try:
+ cdev = _RecursiveAssembleBD(chld_disk, owner, as_primary)
+ except errors.BlockDeviceError, err:
+ if children.count(None) > mcn:
+ raise
+ cdev = None
+ logger.Debug("Error in child activation: %s" % str(err))
+ children.append(cdev)
if as_primary or disk.AssembleOnSecondary():
r_dev = bdev.AttachOrAssemble(disk.dev_type, disk.physical_id, children)
diff --git a/lib/bdev.py b/lib/bdev.py
index 8a80a4c1c..abedc90c2 100644
--- a/lib/bdev.py
+++ b/lib/bdev.py
@@ -1566,6 +1566,8 @@ class DRBD8(BaseDRBD):
_PARSE_SHOW = None
def __init__(self, unique_id, children):
+ if children and children.count(None) > 0:
+ children = []
super(DRBD8, self).__init__(unique_id, children)
self.major = self._DRBD_MAJOR
[kmaj, kmin, kfix, api, proto] = self._GetVersion()
@@ -2030,6 +2032,10 @@ class DRBD8(BaseDRBD):
"C")
if res_r and self._MatchesNet(self._GetDevInfo(minor)):
break
+ # the weakest case: we find something that is only net attached
+ # even though we were passed some children at init time
+ if match_r and "local_dev" not in info:
+ break
else:
minor = None
@@ -2066,7 +2072,7 @@ class DRBD8(BaseDRBD):
minor = self._FindUnusedMinor()
need_localdev_teardown = False
- if self._children[0]:
+ if self._children and self._children[0] and self._children[1]:
result = self._AssembleLocal(minor, self._children[0].dev_path,
self._children[1].dev_path)
if not result:
diff --git a/lib/objects.py b/lib/objects.py
index 9d199c577..507e43d55 100644
--- a/lib/objects.py
+++ b/lib/objects.py
@@ -338,6 +338,22 @@ class Disk(ConfigObject):
return "/dev/%s/%s" % (self.logical_id[0], self.logical_id[1])
return None
+ def ChildrenNeeded(self):
+ """Compute the needed number of children for activation.
+
+ This method will return either -1 (all children) or a positive
+ number denoting the minimum number of children needed for
+ activation (only mirrored devices will usually return >=0).
+
+ Currently, only DRBD8 supports diskless activation (therefore we
+ return 0), for all other we keep the previous semantics and return
+ -1.
+
+ """
+ if self.dev_type == constants.LD_DRBD8:
+ return 0
+ return -1
+
def GetNodes(self, node):
"""This function returns the nodes this device lives on.
--
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