[lustre-discuss] cannot create file for unknown uid

Bernd Melchers melchers at zedat.fu-berlin.de
Fri Aug 30 06:13:16 PDT 2019

Dear all,
we use lustre 2.12.2 (CentOS-7.6) and observe a problem where file
creation for unknown userids is not possible. Background is that
we export our lustre file system with ganesha-nfs (nfs vers. 3) to
nfs clients with userids unknown to the (nfs-)server.

Attached is a short C Program to reproduce the problem.
Process runs as root, changes effective user id to an unknown user id
and creates a file:

/tmp is xfs, /scratch is lustre :
# ls -ld /tmp /scratch/tmp
drwxrwxrwt    9 root root 25600 Jun  3 14:47 /scratch/tmp
drwxrwxrwt. 132 root root 16384 Aug 30 15:06 /tmp

[working for xfs:] # ./debug1_lustre /tmp/testfile && echo success

[not working for lustre:] # ./debug1_lustre /scratch/tmp/testfile
/scratch/tmp/testfile: Permission denied

If i change the uid to a known uid, it works.

Is this a bug in lustre?

Mit freundlichen Grüßen
Bernd Melchers

Archiv- und Backup-Service | fab-service at zedat.fu-berlin.de
Freie Universität Berlin   | Tel. +49-30-838-55905
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