[LU-6553] Recurrence of LU-5299: obd_mount_server.c:1690:osd_start()) ASSERTION( obd ) failed

• Type: Bug
• Resolution: Cannot Reproduce
• Priority: Major
• Affects Version/s: Lustre 2.7.0, Lustre 2.5.4
• Environment: Combined MGT/MDT, racing multiple mount commands.
• Severity: 3
• Assignee: Bruno Faccini (Inactive)
• Reporter: Patrick Farrell (Inactive)

Description

The patch for LU-5573 (http://review.whamcloud.com/#/c/12353/), which closed LU-5299, does not cover some cases.

Specifically, the code which enables the combined MGT/MDT to start correctly also disables the race protection for a combined MGT/MDT.

So racing multiple mount commands on a combined MGT/MDT can still cause this problem.

I've taken a look, and I don't see any easy way to fix this in the current context. I can provide dumps if needed, and I'll attach a log now.

Note the attempts to start MDT0000. There are five, four of which start after the first one but before it has completed.

Issue Links

• is related to: LU-5573 Test timeout conf-sanity test_41c
• is related to: LU-5299 osd_start() LBUG when doing parallel mount of the same target