[lxc-users] Using shiftfs with NFS mounted filesystem

[Narcis Garcia]

https://bugzilla.kernel.org/


Narcis Garcia

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El 19/7/20 a les 1:35, Michael Eager ha escrit:
> On 7/18/20 12:14 PM, Narcis Garcia wrote:
>> This issue seems more apropriate here:
>> https://github.com/containers/fuse-overlayfs
> 
> Why?
> 
> The shiftfs module is a kernel module, not a userspace FUSE implementation.
> 
> 
>>
>>
>> Narcis Garcia
>>
>> __________
>> I'm using this dedicated address because personal addresses aren't
>> masked enough at this mail public archive. Public archive administrator
>> should fix this against automated addresses collectors.
>> El 18/7/20 a les 20:16, Michael Eager ha escrit:
>>> I'm running LXD on a Centos 8 host, kernel-4.18.0.  I built and
>>> installed the shiftfs module.
>>>
>>> I added a device to a container which mounts a local file system in the
>>> container:
>>> $ lxc config device add devel devel disk path=/<container-path>
>>> source=/<host-path> shift=true
>>> (Both container and mounted fs are named "devel".)
>>>
>>> This appears to work with a local FS.  Files which were owned by "root"
>>> on the host system show up as owned by "root" in the container, not by
>>> "nobody".  I can create and delete files normally.
>>>
>>> When the host filesystem is NFS mounted, it initially appears correct in
>>> the container, but there are several odd behaviors:
>>>
>>> Creating a file:
>>> [eager at devel devel]$ cd tmp
>>> [eager at devel tmp]$ ls
>>> [eager at devel tmp]$ touch x
>>> touch: cannot touch 'x': Permission denied
>>> [eager at devel tmp]$ ls -l
>>> total 512
>>> -rw-rw-r-- 1 eager eager 0 Jul 18 17:56 x
>>>
>>> Deleting a file:
>>> [eager at devel tmp]$ rm x
>>> rm: remove write-protected regular empty file 'x'? y
>>> rm: cannot remove 'x': Permission denied
>>> [eager at devel tmp]$ ls -l
>>> total 512
>>> -rw-rw-r-- 1 eager eager 0 Jul 18 17:56 x
>>>
>>> When I remove the file 'x' on the host, it's gone in the container, but
>>> trying to create 'x' again fails with a different error:
>>> [eager at devel tmp]$ ls -l
>>> total 0
>>> [eager at devel tmp]$ touch x
>>> touch: cannot touch 'x': Stale file handle
>>> [eager at devel tmp]$ ls -l
>>> total 0
>>>
>>> But I can create a different file 'y', albeit with the permission error:
>>> [eager at devel tmp]$ touch y
>>> touch: cannot touch 'y': Permission denied
>>> [eager at devel tmp]$ ls -l
>>> total 1.0K
>>> -rw-rw-r-- 1 eager eager 0 Jul 18 18:07 y
>>>
>>>
>>> Something seems to be broken.  Is there a way to fix this?
>>>
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