Hello,
We get a umount.nfs: /mnt: block devices not permitted on fs in a snap
container on Ubuntu.
Can anyone explain what is going wrong?
Thanks,
Martin
?
On Fri, Nov 24, 2023 at 9:57 AM Martin Wege <[email protected]> wrote:
>
> Hello,
>
> We get a umount.nfs: /mnt: block devices not permitted on fs in a snap
> container on Ubuntu.
>
> Can anyone explain what is going wrong?
>
> Thanks,
> Martin
On 29 Nov 2023, at 22:45, Martin Wege wrote:
> ?
>
> On Fri, Nov 24, 2023 at 9:57 AM Martin Wege <[email protected]> wrote:
>>
>> Hello,
>>
>> We get a umount.nfs: /mnt: block devices not permitted on fs in a snap
>> container on Ubuntu.
>>
>> Can anyone explain what is going wrong?
Something in umount is calling umount_error() with -EACCES. I admit that
error message makes no sense, it seems to be cruft.
Maybe you can run the umount in gdb with a breakpoint on umount_error() and
send along the stack.
Ben
On Thu, Nov 30, 2023 at 1:26 PM Benjamin Coddington <[email protected]> wrote:
>
> On 29 Nov 2023, at 22:45, Martin Wege wrote:
>
> > ?
> >
> > On Fri, Nov 24, 2023 at 9:57 AM Martin Wege <[email protected]> wrote:
> >>
> >> Hello,
> >>
> >> We get a umount.nfs: /mnt: block devices not permitted on fs in a snap
> >> container on Ubuntu.
> >>
> >> Can anyone explain what is going wrong?
>
> Something in umount is calling umount_error() with -EACCES. I admit that
> error message makes no sense, it seems to be cruft.
Can this be fixed, please?
>
> Maybe you can run the umount in gdb with a breakpoint on umount_error() and
> send along the stack.
This is much more difficult than I expected - the target system is a
Ubuntu Core system, which uses SNAPs, and debugging there is a
disaster.
Does umount have an extended debug output?
Thanks,
Martin
On 18 Dec 2023, at 3:37, Martin Wege wrote:
> On Thu, Nov 30, 2023 at 1:26 PM Benjamin Coddington <[email protected]> wrote:
>>
>> On 29 Nov 2023, at 22:45, Martin Wege wrote:
>>
>>> ?
>>>
>>> On Fri, Nov 24, 2023 at 9:57 AM Martin Wege <[email protected]> wrote:
>>>>
>>>> Hello,
>>>>
>>>> We get a umount.nfs: /mnt: block devices not permitted on fs in a snap
>>>> container on Ubuntu.
>>>>
>>>> Can anyone explain what is going wrong?
>>
>> Something in umount is calling umount_error() with -EACCES. I admit that
>> error message makes no sense, it seems to be cruft.
>
> Can this be fixed, please?
Probably, have to figure out the problem first.
>> Maybe you can run the umount in gdb with a breakpoint on umount_error() and
>> send along the stack.
>
> This is much more difficult than I expected - the target system is a
> Ubuntu Core system, which uses SNAPs, and debugging there is a
> disaster.
Hm, I don't know what SNAPs are..
> Does umount have an extended debug output?
Not really, maybe try with "strace" and we can see what the kernel's
returning? From there, it might look like flipping on some debugging (check
out the dprintk's in fs/nfs and net/sunrpc and the `rpcdebug` userspace
tool), or maybe some tracepoints would help.
Ben