When defining a ZFS file system using the new IDCAMS parameter ZFS, the file system gets formatted at mount time. When this occurs, the owning ID for the directory is assigned UID=0,GID=1, instead of the uid of the issuer of the mount command. For example:
Then mount a ZFS file system that was created by user1 (uid=0010000999) using the IDCAMS parameter ZFS.
mount -f user1.TEST.ZFS zfs
This changes the owner id of the directory to STCSYS which is UID=0.
There is a permit to the all record for
Release : 1.6
Component : CA Top Secret for z/OS
What is happening here is actually due to being in a USS file sharing sysplex (BPXPRMxx is SYSPLEX=YES) . Even though you are issuing the MOUNT from your own NON ID 0 userid, that has been given authority to MOUNT via the access to UNIXPRIV SUPERUSER.FILESYS.MOUNT. The mount is actually running on a USS tcb when zFS processes it. This results in the osi_getcred returning UID 0, which is then used , correctly, as the owner.
In a stand alone system environment (NOT a USS File sharing sysplex, or SYSPLEX=NO), the behavior is different. In that case the mount request runs on a tcb associated with the USERs asid (NOT USS, as in the above SYSPLEX=YES environment). This then correctly results in the osi_getcred returning the UID of the user that issue the mount, which is then (also) correctly used as the owner.