[LU-3616] HSM restore for execute allows writes to file

• Type: Technical task
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.6.0, Lustre 2.5.1
• Affects Version/s: Lustre 2.5.0
• Labels: HSM
• Assignee: Bruno Faccini (Inactive)
• Reporter: John Hammond

Description

Using the Jul 22, 2013 HSM stack, executing a released file (and thereby triggering a restore) leaves the file writable while it's being executed.

# cd /mnt/lustre
# cp /bin/sleep SLEEP
# lfs hsm_archive SLEEP
# sleep 1
# lfs hsm_release SLEEP
# ./SLEEP 10 && echo DONE &
[1] 4243
# sleep 1
# pgrep -l SLEEP
4244 SLEEP
# cd /mnt/lustre2
# echo 'Hi!' > SLEEP
# cat SLEEP
Hi!
# -bash: line 238:  4244 Bus error               (core dumped) ./SLEEP 10

[1]+  Exit 135                ./SLEEP 10 && echo DONE  (wd: /mnt/lustre)
(wd now: /mnt/lustre2)

Comments

[Peter Jones]

Yes it is being tracked for 2.5.1.

[Aurelien Degremont (Inactive)]

This should also be considered for 2.5.1

[Peter Jones]

Landed for 2.6

[Bruno Faccini (Inactive)]

Patch-set #2 of Change #7636 successfully passed auto-tests including its own+new sanity-hsm/test_30c sub-test.

This allows restore on exec() to continue to work but now prevents any write to be allowed during exec() and make it fail.

BTW, reading code of sub-tests test_30[a,b], against same exec() on released files area, I have been surprised by the following comment :

# restore at exec cannot work on agent node (because of Linux kernel
# protection of executables)
needclients 2 || return 0
...

at their beginning.
Is it (comment and "needclients 2") still of actuality, because as per my latest tests, restore at exec() also works on Agent-Node (I mean I tested on a single+full node ...) ?

[Bruno Faccini (Inactive)]

1st patch-set of http://review.whamcloud.com/7636 successfully passed auto-tests and also did not trigger the original problem when running John's reproducer.

I will submit a new version/patch-set #2 with the same code but adding a specific+new sub-test in sanity-hsm, based on John's reproducer.

[Bruno Faccini (Inactive)]

1st patch attempt is at http://review.whamcloud.com/7636. Build is ok but auto-tests never started ...
So, I just re-triggered auto-tests.