Recursive mounts with kAFS, but not with OpenAFS

[Jeffrey E Altman]

On 5/4/2024 5:04 PM, Jeffrey Altman wrote:
> On May 3, 2024, at 6:20 AM, Jan Henrik Sylvester 
> <jan.henrik.sylvester at uni-hamburg.de> wrote:
>> and a simple execution of find on a home directory had a machine hang by the oom-killer killing vital system processes, because kAFS can go more than a 1000 levels recursively into ~/AFSBAK/AFSBAK/AFSBAK...
> Markus Suvanto reported the same problem on Feb 20th.   At the time Marc Dionne developed a patch to prevent the evaluation of a mount point to a volume name with the “.backup” extension from a volume of type AFSVL_BACKVOL.   Testing of the patch wasn’t complete so it did not get submitted.   Hopefully Marc can submit it next week.   Once merged by Linus it can be back ported to the actively maintained stable kernels.
>> The volume user is mounted to /afs/math.uni-hamburg.de/users/area/user and user.backup is mounted to /afs/math.uni-hamburg.de/users/area/user/AFSBAK. Should /afs/math.uni-hamburg.de/users/area/user/AFSBAK/AFSBAK automatically be a mount point?
> It's a mount point but should not be traversed.

Marc's patch has been merged into upstream and Greg has queued the patch 
for inclusion in the next 6.9, 6.6, 6.1, 5.15, 5.10, and 5.4 stable 
releases.  Most likely 6.9.5, 6.6.34, 6.1.94, 5.15.161, 5.10.218, 5.4.278.  The patch will be available in the distros when they update to one of those kernels or a later release.

You can file a bug report report against Ubuntu 24.04 and reference that the bug has been fixed by commit 29be9100aca2915fab54b5693309bc42956542e5 upstream.

Thanks for the bug report.

We hope that kafs meets the needs of your end users.

Jeffrey Altman