[LU-19989] FLR-EC-IWM: connect flag, feature gating, and LCME_FL_IMMEDIATE flag

• Type: Technical task
• Resolution: Unresolved
• Priority: Medium
• Labels: FLR-EC FLR-EC-IWM
• Severity: 3
• Assignee: WC Triage
• Reporter: Patrick Farrell

Description

Define OBD_CONNECT2_FLR_IMMED_MIRROR gating infrastructure and the LCME_FL_IMMEDIATE layout flag for immediate write mirroring.

Connect flag and gating (following EC pattern, Gerrit 62217):

• Connect flag enabled by default (client and server module params)
• Per-mount enable_immediate_mirror defaults to 0 (disabled) until the feature is ready
• Client rejects layouts containing LCME_FL_IMMEDIATE components when per-mount flag is off

LCME_FL_IMMEDIATE flag (following EC pattern, Gerrit 61962):

• Add to enum lov_comp_md_entry_flags (lustre_user.h)
• Add to LCME_KNOWN_FLAGS, LCME_USER_COMP_FLAGS, LCME_CL_COMP_FLAGS, LCME_TEMPLATE_FLAGS
• Add { LCME_FL_IMMEDIATE, "immediate" }

  to comp_flags_table (lustreapi.h) so --comp-flags immediate works

• LCME_FL_IMMEDIATE and LCME_FL_PARITY are mutually exclusive on a component

Reference EC patches:

• Gerrit 62217: LU-12187 llite: add FLR EC support and enable switches (connect flag + gating pattern)
• Gerrit 61962: LU-12187 llapi: EC layout creation support (flag + llapi pattern)

Prototype patches:

• Gerrit 59597: immediate mirror flag
• Gerrit 59570: userspace tools

Issue Links

• is blocking: LU-19991 FLR-EC-IWM: llapi layout support and kernel layout passthrough for immediate mirrors
• is duplicated by: LU-19990 FLR-EC-IWM: LCME_FL_IMMEDIATE flag and llapi layout support