[LU-5564] open handle leak after setuid()

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.9.0
• Affects Version/s: Lustre 2.7.0
• Labels: mdt
• Severity: 3
• Assignee: Hongchao Zhang
• Reporter: John Hammond

Description

MDS_CLOSE RPCs are sent with the current_fs{uid,gid}(). If this id cannot be resolved on the MDT then mdt_close() fails in unpack and the open handle is never released.

# MOUNT_2=y llmount.sh
...
# id 42
id: 42: No such user
# cp /bin/sleep /mnt/lustre/sleep
# chown 42:42 /mnt/lustre/sleep
# chmod ug+s /mnt/lustre/sleep
# /mnt/lustre/sleep 0
# echo > /mnt/lustre2/sleep
-bash: /mnt/lustre2/sleep: Text file busy

[  475.032992] LustreError: 6559:0:(file.c:186:ll_close_inode_openhandle()) lustre-clilmv-ffff8802173141c8: inode [0x200000400:0x3:0x0] mdc close failed: rc = -13

Seems a bit broken this way. With the exception of HSM release why check process permissions at close? The open FD (open handle) gives us permission.