[LU-10843] snapshot_create fails after MGS restart

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.12.0, Lustre 2.10.5
• Affects Version/s: Lustre 2.10.3
• Severity: 3
• Assignee: Nathaniel Clark
• Reporter: Nathaniel Clark

Description

If the MGS is unmounted and remount (or failed over) lctl snapshot_create fails with the following error:

# lctl snapshot_create -F scratch -n test
Fail to freeze barrier for scratch: No such device
Can't create the snapshot test

snapshot_destroy still works without issue.

WORKAROUND: unmount/mount the MDT and snapshot_create will commence working again.

NOTE: mount -o remount is insufficient