[LU-724] CLIO does not set lock handle in BRW

• Status: Closed
• Project: Lustre
• Affects Version/s: Lustre 2.1.0
• Type: Bug
• Priority: Minor
• Reporter: Johann Lombardi (Inactive)
• Assignee: Jinshan Xiong (Inactive)
• Resolution: Won't Fix
• Severity: 3

Description

Unlike b1_8, CLIO does not set a valid lock handle in bulk write requests. osc_build_req() still uses oap->oap_ldlm_lock to fill the lock handle, but oap_ldlm_lock is always NULL, so we end up with oa->o_handle = NULL in requests.

We have been discussing for a while that all - when relevant of course - requests should specify a lock handle, so this is really a regression from this regard.
This lock handle is also used on the OST side to determine whether or not a BRW should make processed as a HP request. Not providing a lock handle put more load on the OST (e.g. in ost_rw_hpreq_check->ost_rw_prolong_locks()) since we always have to iterate over the list of dlm locks.

Comments

[Jinshan Xiong (Inactive)]

Yup there exists dead code in osc_build_req() where it refers to ->oap_ldlm_lock for dlm lock and this field should be always NULL. However, it doesn't affect OBD_MD_FLHANDLE because it is handle in cl_req_attr_set -> osc_req_attr_set and osc_req_attr_set will find a dlm lock and set remote handle.

The purpose for clio to keep obsoleted code is to leave a door open if something doesn't work . Now that clio looks stable, I think it's okay to remove those obsoleted code.

[Johann Lombardi (Inactive)]

Ah, great, i missed this code path. Thanks.