def _write_info_file(self, info_path, snap_info):
if 'active' not in snap_info.keys():
msg = _("'active' must be present when writing snap_info.")
raise exception.RemoteFSException(msg)
with open(info_path, 'w') as f:
json.dump(snap_info, f, indent=1, sort_keys=True)
def _qemu_img_info_base(self, path, volume_name, basedir):
"""Sanitize image_utils' qemu_img_info.
This code expects to deal only with relative filenames.
"""
info = image_utils.qemu_img_info(path)
if info.image:
info.image = os.path.basename(info.image)
if info.backing_file:
backing_file_template = \
"(%(basedir)s/[0-9a-f]+/)?%" \
"(volname)s(.(tmp-snap-)?[0-9a-f-]+)?$" % {
'basedir': basedir,
'volname': volume_name
}
if not re.match(backing_file_template, info.backing_file):
msg = _("File %(path)s has invalid backing file "
"%(bfile)s, aborting.") % {
'path': path,
'bfile': info.backing_file
}
raise exception.RemoteFSException(msg)
info.backing_file = os.path.basename(info.backing_file)
return info
def _ensure_share_writable(self, path):
"""Ensure that the Cinder user can write to the share.
If not, raise an exception.
:param path: path to test
:raises: RemoteFSException
:returns: None
"""
prefix = '.cinder-write-test-' + str(os.getpid()) + '-'
try:
tempfile.NamedTemporaryFile(prefix=prefix, dir=path)
except OSError:
msg = _('Share at %(dir)s is not writable by the '
'Cinder volume service. Snapshot operations will not be '
'supported.') % {
'dir': path
}
raise exception.RemoteFSException(msg)
def _create_snapshot_online(self, snapshot, backing_filename,
new_snap_path):
# Perform online snapshot via Nova
context = snapshot['context']
self._do_create_snapshot(snapshot, backing_filename, new_snap_path)
connection_info = {
'type': 'qcow2',
'new_file': os.path.basename(new_snap_path),
'snapshot_id': snapshot['id']
}
try:
result = self._nova.create_volume_snapshot(context,
snapshot['volume_id'],
connection_info)
LOG.debug('nova call result: %s' % result)
except Exception as e:
LOG.error(_('Call to Nova to create snapshot failed'))
LOG.exception(e)
raise e
# Loop and wait for result
# Nova will call Cinderclient to update the status in the database
# An update of progress = '90%' means that Nova is done
seconds_elapsed = 0
increment = 1
timeout = 600
while True:
s = db.snapshot_get(context, snapshot['id'])
if s['status'] == 'creating':
if s['progress'] == '90%':
# Nova tasks completed successfully
break
time.sleep(increment)
seconds_elapsed += increment
elif s['status'] == 'error':
msg = _('Nova returned "error" status '
'while creating snapshot.')
raise exception.RemoteFSException(msg)
LOG.debug('Status of snapshot %(id)s is now %(status)s' % {
'id': snapshot['id'],
'status': s['status']
})
if 10 < seconds_elapsed <= 20:
increment = 2
elif 20 < seconds_elapsed <= 60:
increment = 5
elif 60 < seconds_elapsed:
increment = 10
if seconds_elapsed > timeout:
msg = _('Timed out while waiting for Nova update '
'for creation of snapshot %s.') % snapshot['id']
raise exception.RemoteFSException(msg)
def _delete_snapshot(self, snapshot):
"""Delete a snapshot.
If volume status is 'available', delete snapshot here in Cinder
using qemu-img.
If volume status is 'in-use', calculate what qcow2 files need to
merge, and call to Nova to perform this operation.
:raises: InvalidVolume if status not acceptable
:raises: RemotefsException(msg) if operation fails
:returns: None
"""
LOG.debug('Deleting snapshot %s:' % snapshot['id'])
volume_status = snapshot['volume']['status']
if volume_status not in ['available', 'in-use']:
msg = _('Volume status must be "available" or "in-use".')
raise exception.InvalidVolume(msg)
self._ensure_share_writable(self._local_volume_dir(snapshot['volume']))
# Determine the true snapshot file for this snapshot
# based on the .info file
info_path = self._local_path_volume_info(snapshot['volume'])
snap_info = self._read_info_file(info_path, empty_if_missing=True)
if snapshot['id'] not in snap_info:
# If snapshot info file is present, but snapshot record does not
# exist, do not attempt to delete.
# (This happens, for example, if snapshot_create failed due to lack
# of permission to write to the share.)
LOG.info(
_('Snapshot record for %s is not present, allowing '
'snapshot_delete to proceed.') % snapshot['id'])
return
snapshot_file = snap_info[snapshot['id']]
LOG.debug('snapshot_file for this snap is: %s' % snapshot_file)
snapshot_path = os.path.join(
self._local_volume_dir(snapshot['volume']), snapshot_file)
snapshot_path_img_info = self._qemu_img_info(snapshot_path)
vol_path = self._local_volume_dir(snapshot['volume'])
# Find what file has this as its backing file
active_file = self.get_active_image_from_info(snapshot['volume'])
active_file_path = os.path.join(vol_path, active_file)
if volume_status == 'in-use':
# Online delete
context = snapshot['context']
base_file = snapshot_path_img_info.backing_file
if base_file is None:
# There should always be at least the original volume
# file as base.
msg = _('No backing file found for %s, allowing snapshot '
'to be deleted.') % snapshot_path
LOG.warn(msg)
# Snapshot may be stale, so just delete it and update ther
# info file instead of blocking
return self._delete_stale_snapshot(snapshot)
base_path = os.path.join(
self._local_volume_dir(snapshot['volume']), base_file)
base_file_img_info = self._qemu_img_info(base_path)
new_base_file = base_file_img_info.backing_file
base_id = None
for key, value in snap_info.iteritems():
if value == base_file and key != 'active':
base_id = key
break
if base_id is None:
# This means we are deleting the oldest snapshot
msg = 'No %(base_id)s found for %(file)s' % {
'base_id': 'base_id',
'file': snapshot_file
}
LOG.debug(msg)
online_delete_info = {
'active_file': active_file,
'snapshot_file': snapshot_file,
'base_file': base_file,
'base_id': base_id,
'new_base_file': new_base_file
}
return self._delete_snapshot_online(context, snapshot,
online_delete_info)
if snapshot_file == active_file:
# Need to merge snapshot_file into its backing file
# There is no top file
# T0 | T1 |
# base | snapshot_file | None
# (guaranteed to| (being deleted) |
# exist) | |
base_file = snapshot_path_img_info.backing_file
self._img_commit(snapshot_path)
# Remove snapshot_file from info
del (snap_info[snapshot['id']])
# Active file has changed
snap_info['active'] = base_file
self._write_info_file(info_path, snap_info)
else:
# T0 | T1 | T2 | T3
# base | snapshot_file | higher_file | highest_file
# (guaranteed to | (being deleted)|(guaranteed to | (may exist,
# exist, not | | exist, being | needs ptr
# used here) | | committed down)| update if so)
backing_chain = self._get_backing_chain_for_path(
snapshot['volume'], active_file_path)
# This file is guaranteed to exist since we aren't operating on
# the active file.
higher_file = next(
(os.path.basename(f['filename']) for f in backing_chain
if f.get('backing-filename', '') == snapshot_file), None)
if higher_file is None:
msg = _('No file found with %s as backing file.') %\
snapshot_file
raise exception.RemoteFSException(msg)
higher_id = next(
(i for i in snap_info
if snap_info[i] == higher_file and i != 'active'), None)
if higher_id is None:
msg = _('No snap found with %s as backing file.') %\
higher_file
raise exception.RemoteFSException(msg)
# Is there a file depending on higher_file?
highest_file = next(
(os.path.basename(f['filename']) for f in backing_chain
if f.get('backing-filename', '') == higher_file), None)
if highest_file is None:
msg = 'No file depends on %s.' % higher_file
LOG.debug(msg)
# Committing higher_file into snapshot_file
# And update pointer in highest_file
higher_file_path = os.path.join(vol_path, higher_file)
self._img_commit(higher_file_path)
if highest_file is not None:
highest_file_path = os.path.join(vol_path, highest_file)
snapshot_file_fmt = snapshot_path_img_info.file_format
self._rebase_img(highest_file_path, snapshot_file,
snapshot_file_fmt)
# Remove snapshot_file from info
del (snap_info[snapshot['id']])
snap_info[higher_id] = snapshot_file
if higher_file == active_file:
if highest_file is not None:
msg = _('Check condition failed: '
'%s expected to be None.') % 'highest_file'
raise exception.RemoteFSException(msg)
# Active file has changed
snap_info['active'] = snapshot_file
self._write_info_file(info_path, snap_info)