[LU-12712] sanity-pfl tests triggering “not SEL magic on SEL file”

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.13.0
• Affects Version/s: Lustre 2.13.0
• Severity: 3
• Assignee: Andreas Dilger
• Reporter: James Nunez (Inactive)

Description

Looking at the console log for MDSs when running sanity-pfl, we are seeing messages like

[13646.271068] Lustre: 21851:0:(lod_lov.c:1358:lod_parse_striping()) lustre-MDT0001-mdtlov: not SEL magic on SEL file [0x240014454:0x77a:0x0]: bd30bd0
[13646.274907] Lustre: 21851:0:(lod_lov.c:1358:lod_parse_striping()) lustre-MDT0001-mdtlov: not SEL magic on SEL file [0x240014454:0x77a:0x0]: bd30bd0

We are seeing this for sanity-pfl tests 19e, 20b, 20c and 20d and when cleaning up after sanity-pfl.

Examples of this message in the MDS (vm4 and vm5) console logs are at
https://testing.whamcloud.com/test_sets/fedacd8c-c944-11e9-90ad-52540065bddc
https://testing.whamcloud.com/test_sets/b04ecaf6-c953-11e9-97d5-52540065bddc

Issue Links

• is related to: LU-13143 detect console spew during (interop) testing
• is related to: LU-10070 PFL self-extending file layout

Comments

[Peter Jones]

Landed for 2.13

[Gerrit Updater]

Oleg Drokin ([e-mail]) merged in patch https://review.whamcloud.com/36351/
Subject: LU-12712 lod: fix warning message for non-SEL file
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 544fd725dc5773aa8fdd931e04eb51d658ee1686

[Gerrit Updater]

Andreas Dilger ([e-mail]) uploaded a new patch: https://review.whamcloud.com/36351
Subject: LU-12712 lod: fix warning message for non-SEL file
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: ecfc198003dba32d24805f2daa3fe8aa4d4706cb

[Andreas Dilger]

Looking at this more closely, it appears that there is just a bug in how the check is done for the error message, since it is checking the magic of the component (which is always LOV_MAGIC_V3) instead of the magic for the file (which should be LOV_MAGIC_SEL).

That said, it isn't totally clear what can/should be done with this error message, if it should legitimately be hit in the field, as opposed to (IMHO) being spuriously printed because of a defect in the logic. Clearly it is a discrepancy in the on-disk format, but it doesn't appear to be harmful. However, it would be better if there was an LFSCK check for this and a repair, since no administrator would be able to fix this short of deleting the file, and it will just be console noise.

[Peter Jones]

vitaly_fertman Cory reported on the LWG call that you considered this to be a lower priority issue. As such is it ok for this test to be added to the always except list until it can be fixed properly in a future release?

[Patrick Farrell (Inactive)]

Having taken a look at this, these are all of the sanity-pfl tests which have SEL & replay in them.

The issue seems to be this:
https://review.whamcloud.com/#/c/35144/8/lustre/lod/lod_object.c@1551

I'm hoping Vitaly can comment on why that line is there, because I can't see why it's there at all.

Also, as noted there, I think once this warning is fixed, we should make it return an error or assert or something - It is an on disk format discrepancy, and the warning clearly isn't enough, because I believe it's been triggering ever since it was added.