Live-server installation fails to install on Samsung NVME

[Sherry Hurwitz]

Both the 18.04.2 and 19.04 live-server installer (subiquity) fail to install with on a Samsung NVME drive. The probe for drive properties fails with the following Traceback:
Traceback (most recent call last):
  File "/snap/subiquity/1093/lib/python3.6/site-packages/subiquity/controllers/filesystem.py", line 89, in _probed
    storage = fut.result()
  File "/snap/subiquity/1093/usr/lib/python3.6/concurrent/futures/_base.py", line 425, in result
    return self.__get_result()
  File "/snap/subiquity/1093/usr/lib/python3.6/concurrent/futures/_base.py", line 384, in __get_result
    raise self._exception
  File "/snap/subiquity/1093/usr/lib/python3.6/concurrent/futures/thread.py", line 56, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/snap/subiquity/1093/lib/python3.6/site-packages/subiquity/controllers/filesystem.py", line 81, in _bg_probe
    return self.prober.get_storage(probe_types=probe_types)
  File "/snap/subiquity/1093/lib/python3.6/site-packages/subiquitycore/prober.py", line 69, in get_storage
    results = storage.probe(probe_types=probe_types)
  File "/snap/subiquity/1093/lib/python3.6/site-packages/probert/storage.py", line 181, in probe
    probed_data[ptype] = pfunc(context=self.context)
  File "/snap/subiquity/1093/lib/python3.6/site-packages/probert/filesystem.py", line 37, in probe
    if device['MAJOR'] not in ["1", "7"]:
  File "/snap/subiquity/1093/lib/python3.6/site-packages/pyudev/device/_device.py", line 957, in __getitem__
    return self.properties.__getitem__(prop)
  File "/snap/subiquity/1093/lib/python3.6/site-packages/pyudev/device/_device.py", line 1084, in __getitem__
    raise KeyError(prop)
KeyError: 'MAJOR'

[Ryan Harper (raharper)]

This looks related:

https://bugs.launchpad.net/ubuntu/+source/mountall/+bug/1807077

[Sherry Hurwitz (shurwitz)]

It is similar in that a property is missing so the dictionary errors out but in this case the error is in probert in the storage.py in the blockdev probe. when all the devices in in the block subsystem are listed:

for device in context.list_devices(subsystem='block'):
    if device['MAJOR'] not in ["1", "7"]:
        attrs = udev_get_attributes(device)

The Samsung PM1725b is a dual port drive providing two access paths to the controller. It looks like this capability causes two device entries to be reported in the device list (wwid are the same):

Device('/sys/devices/pci0000:e0/0000:e0:03.3/0000:e2:00.0/nvme/nvme0/nvme0c33n1')
{'alignment_offset': '0', 'capability': '630', 'device': None, 'discard_alignment': '0', 'ext_range': '0', 'hidden': '1', 'inflight': ' 0 0', 'nguid': '34433930-4ba0-0316-0025-385900000003', 'nsid': '1', 'range': '0', 'removable': '0', 'ro': '0', 'size': '3125627568', 'stat': ' 592 0 18048 48 0 0 0 0 0 4 8', 'subsystem': 'block', 'uevent': 'DEVTYPE=disk', 'uuid': '34433930-4ba0-0316-0025-385900000003', 'wwid': 'eui.344339304ba003160025385900000003'}

Device('/sys/devices/virtual/nvme-subsystem/nvme-subsys0/nvme0n1')
{'alignment_offset': '0', 'bdi': None, 'capability': '50', 'dev': '259:1', 'device': None, 'discard_alignment': '0', 'ext_range': '256', 'hidden': '0', 'inflight': ' 0 0', 'nguid': '34433930-4ba0-0316-0025-385900000003', 'nsid': '1', 'range': '0', 'removable': '0','ro': '0', 'size': '3125627568', 'stat': ' 0 0 0 0 0 0 0 0 0 0 0', 'subsystem': 'block', 'uevent': 'MAJOR=259\nMINOR=1\nDEVNAME=nvme0n1\nDEVTYPE=disk', 'uuid': '34433930-4ba0-0316-0025-385900000003', 'wwid': 'eui.344339304ba003160025385900000003'}

The first entry has the hidden property set and is lacking the MAJOR/MINOR/DEVNAME properties. Maybe to fix the bug the probe function should skip any hidden entries and just use the non-hidden entry when there are duplicates?

[Ryan Harper (raharper)]

On Thu, Aug 15, 2019 at 11:56 AM Sherry Hurwitz <email address hidden>
wrote:

> It is similar in that a property is missing so the dictionary errors out
> but in this case the error is in probert in the storage.py in the
> blockdev probe. when all the devices in in the block subsystem are
> listed:
>
>
> for device in context.list_devices(subsystem='block'):
> if device['MAJOR'] not in ["1", "7"]:
> attrs = udev_get_attributes(device)
>
> The Samsung PM1725b is a dual port drive providing two access paths to
> the controller. It looks like this capability causes two device entries
> to be reported in the device list (wwid are the same):
>
>
> Device('/sys/devices/pci0000:e0/0000:e0:03.3/0000:e2:00.0/nvme/nvme0/nvme0c33n1')
> {'alignment_offset': '0', 'capability': '630', 'device': None,
> 'discard_alignment': '0', 'ext_range': '0', 'hidden': '1', 'inflight': '
> 0 0', 'nguid': '34433930-4ba0-0316-0025-385900000003', 'nsid':
> '1', 'range': '0', 'removable': '0', 'ro': '0', 'size': '3125627568',
> 'stat': ' 592 0 18048 48 0 0 0
> 0 0 4 8', 'subsystem': 'block', 'uevent':
> 'DEVTYPE=disk', 'uuid': '34433930-4ba0-0316-0025-385900000003', 'wwid':
> 'eui.344339304ba003160025385900000003'}
>
> Device('/sys/devices/virtual/nvme-subsystem/nvme-subsys0/nvme0n1')
> {'alignment_offset': '0', 'bdi': None, 'capability': '50', 'dev': '259:1',
> 'device': None, 'discard_alignment': '0', 'ext_range': '256', 'hidden':
> '0', 'inflight': ' 0 0', 'nguid':
> '34433930-4ba0-0316-0025-385900000003', 'nsid': '1', 'range': '0',
> 'removable': '0','ro': '0', 'size': '3125627568', 'stat': ' 0
> 0 0 0 0 0 0 0 0 0
> 0', 'subsystem': 'block', 'uevent':
> 'MAJOR=259\nMINOR=1\nDEVNAME=nvme0n1\nDEVTYPE=disk', 'uuid':
> '34433930-4ba0-0316-0025-385900000003', 'wwid':
> 'eui.344339304ba003160025385900000003'}
>
> The first entry has the hidden property set and is lacking the
> MAJOR/MINOR/DEVNAME properties. Maybe to fix the bug the probe function
> should skip any hidden entries and just use the non-hidden entry when
> there are duplicates?
>

Thank you for the extra info from the device. I believe your suggestion is
the correct fix here.

>
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> https://bugs.launchpad.net/bugs/1839529
>
> Title:
> Live-server installation fails to install on Samsung NVME
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[Michael Hudson-Doyle (mwhudson)]

I think this bug is fixed in the 20.04 ISO but am not completely sure...