[LU-2142] "lctl lfsck_start" should start a scrub

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Lustre 2.3.0, Lustre 2.4.0
• Fix Version/s: Lustre 2.3.0, Lustre 2.4.0
• Severity: 3
• Assignee: nasf (Inactive)
• Reporter: Andreas Dilger

Description

Running "lctl lfsck_start -M

{fsname}

-MDT0000" should start a scrub, unless one is already running. However, if the scrub was previously run and completed (leaving last_checkpoint_position == inode_count, it appears a new scrub will not be run because the start position is not reset at the end of the previous lfsck run or the start of the new run:

latest_start_position: 143392770
last_checkpoint_position: 143392769

It makes sense to restart the scrub at the last checkpoint position if it didn't complete for some reason, but if latest_start_position >= inode_count then the start position should be reset to start again. Both Cliff and I were confused by the current behaviour, and it took us a while to determine that "-r" was needed, and I expect that most users will have the same problem. The "-r" option should only be needed in case the admin has to handle some unusual condition where a previous scrub was interrupted, but a new full scrub is desired.