[LU-15001] improve recovery of interrupted directory migrate

• Type: Improvement
• Resolution: Unresolved
• Priority: Minor
• Assignee: WC Triage
• Reporter: Andreas Dilger

Description

Currently, if a directory migration has been interrupted (e.g. MDS crash), nothing is done to resume the migration operation. This is precautionary, in case there was something with the migration operation itself that caused the problem.

However, to resume the migration operation, the exact same options for "lfs migrate -m" need to be specified by the user in order to resume/finish the migration. It would be much more convenient in this case if the migration could be resumed without having to specify the same options, and the MDS would just "know" these options if asked to migrate the directory again. That simplifies the user handling, and (AFAICS) does not add any risk since the migration request from the user will fail if the same options are not specified.

Issue Links

• is related to: LU-14719 "lfs migrate -m" creates broken agent inodes when target MDT full
• is related to: LU-14975 DNE3: directory migration in non-recursive mode
• is related to: LU-14211 DNE3: mechanism to interrupt and resume migration
• is related to: LU-11776 add "lfs find" support for directory hash flags
• is related to: LU-15990 "lfs find" to scan for directory hash flags
• is related to: LU-13492 lfs migrate -m returns Operation not permitted
• is related to: LU-14975 DNE3: directory migration in non-recursive mode