openstack
/
nova
Code Issues Proposed changes

Have device mapping use autocreated device nodes 

Newer kernels detect partitions and create device
nodes when an image is opened with qemu-nbd. Calling
kpartx afterwards will always result in failures
and prevent injection of data into the current image.

The fix tries to handle this by detecting if a device
node exists and call kpartx only if needed.

Change-Id: I781158ea94f9f0762140e106dd6a1259017b8a3b
This commit is contained in:
Clemens Perz 2012-09-07 19:08:04 +02:00
parent bfce34fdd9
commit 1b87d59da1
1 changed files with 14 additions and 3 deletions
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17
nova/virt/disk/mount.py
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@ -43,7 +43,7 @@ class Mount(object):
self.error = ""
# Internal
self.linked = self.mapped = self.mounted = False
self.linked = self.mapped = self.mounted = self.automapped = False
self.device = self.mapped_device = device
# Reset to mounted dir if possible
@ -76,10 +76,12 @@ class Mount(object):
def map_dev(self):
"""Map partitions of the device to the file system namespace."""
assert(os.path.exists(self.device))
automapped_path = '/dev/%sp%s' % (os.path.basename(self.device),
self.partition)
if self.partition == -1:
self.error = _('partition search unsupported with %s') % self.mode
elif self.partition:
elif self.partition and not os.path.exists(automapped_path):
map_path = '/dev/mapper/%sp%s' % (os.path.basename(self.device),
self.partition)
assert(not os.path.exists(map_path))
@ -99,6 +101,14 @@ class Mount(object):
else:
self.mapped_device = map_path
self.mapped = True
elif self.partition and os.path.exists(automapped_path):
# Note auto mapping can be enabled with the 'max_part' option
# to the nbd or loop kernel modules. Beware of possible races
# in the partition scanning for _loop_ devices though
# (details in bug 1024586), which are currently uncatered for.
self.mapped_device = automapped_path
self.mapped = True
self.automapped = True
else:
self.mapped_device = self.device
self.mapped = True
@ -109,9 +119,10 @@ class Mount(object):
"""Remove partitions of the device from the file system namespace."""
if not self.mapped:
return
if self.partition:
if self.partition and not self.automapped:
utils.execute('kpartx', '-d', self.device, run_as_root=True)
self.mapped = False
self.automapped = False
def mnt_dev(self):
"""Mount the device into the file system."""