Question regarding container affecting the system mounts

[ronak_desai]

Hi,

I came a cross a problem where if the containers are running then it
affects the unmount process of the system's mount points. I am not
using these mount points as shared partitions with container.

For example, I am using SD card and NAND as external storage device
and mounting it to a mount point in the ramfs. Then I am launching
containers and then when I try to unmount the NAND partition then my
"unmount" call succeeds but I don't see the UBIFS hooks being called
and because of that my UBI detach process fails. When I stopped the
container then I see that kernel is calling the unmount as I see my
debug prints inside the UBIFS for unmounting that partition. It seems
like the calls are buffered/queued because of container.

If I tried to mount my NAND partition once the container is up and try
to unmount then it does unmount and detach without issue. It seems
like there is an issue with namespace.

I am using 4.1.8 kernel from SDK 2.0 . Please let me know if you need any
additional detail from my end.

Thanks in advance !

Thanks,

Ronak

[ronak_desai]

I am able to workaround this issue by marking the mount as unbinadable and clearing the flag (CL_COPY_UNBINDABLE) in "copy_tree" function in fs/namespace.c. This skips the unbindable mounts to get cloned inside the new namespace. For my use-case this is acceptable.

Thanks,

Ronak

[ronak_desai]

I am able to workaround this issue by marking the mount as unbinadable and clearing the flag (CL_COPY_UNBINDABLE) in "copy_tree" function in fs/namespace.c. This skips the unbindable mounts to get cloned inside the new namespace. For my use-case this is acceptable.

Thanks,

Ronak