[LU-3302] ll_fill_super() Unable to process log: -2

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.4.0
• Affects Version/s: Lustre 2.4.0
• Labels: LB
• Environment: PPC client
• Severity: 3
• Assignee: Di Wang
• Reporter: Ned Bass (Inactive)

Description

We updated a client to 2.3.64-4chaos and tried to mount a 2.3.63-6chaos server. The mount fails with

LustreError: 15c-8: MGC172.20.20.201@o2ib500: The configuration from log 'fsv-client' failed (-2). This may be the result of communication errors between this node and the MGS, a bad configuration, or other errors. See the syslog for more information.
LustreError: 14351:0:(llite_lib.c:1043:ll_fill_super()) Unable to process log: -2
Lustre: Unmounted fsv-client
LustreError: 14351:0:(obd_mount.c:1265:lustre_fill_super()) Unable to mount  (-2)

Using git bisect I found the mount failure was introduced with this patch:

http://review.whamcloud.com/#change,5820

LU-2684 fid: unify ostid and FID

The critical questions at this point are:

• Can we solve this problem by updating both server and client to 2.3.64-4chaos?

• Can we safely upgrade the server, or does the above patch introduce on-disk format incompatibilities?

• Will we be able to safely revert the server to 2.3.63 in case we find problems, or will it write new objects in an incompatible format?

LLNL-bug-id: TOSS-2060

Issue Links

• is related to: LU-3294 osp_sync_llog_init(): ASSERTION( lgh != ((void *)0) ) failed