[LU-13602] Skip unknown FLR component types

• Type: Bug
• Resolution: Fixed
• Priority: Critical
• Fix Version/s: Lustre 2.15.0
• Severity: 3
• Assignee: Qian Yingjin
• Reporter: Li Xi

Description

Currently, in lov_init_composite() will quit with error when reading an unknown LOV pattern:

			CERROR("%s: unknown composite layout entry type %i\n",
			       lov2obd(dev->ld_lov)->obd_name,
			       lsm->lsm_entries[i]->lsme_pattern);

Since FLR will be used for upcoming new features, like PCC-RO, an old client should still be able to read the old format mirrors and ignore the new types of mirrors.

On the MDS, it should skip mirrors with unknown/foreign component types and mark them stale when selecting which component to use for writes.

Issue Links

• is related to: LU-14389 crash in lov_delete_composite() with racer+migrate
• is related to: LU-13637 Combining RO-PCC/RW-PCC/HSM with FLR HLD
• is related to: LU-10499 Readonly Persistent Client Cache support
• is related to: LU-14319 Make foreign layout as a mirror component