DAOS-18531 vos: setup ts_set in vos_obj_incarnate()

[NiuYawei]

Replace the vos_obj_hold() call before vos_obj_incarnate() with vos_obj_acquire() to ensure the ts_set setup is fully done within transaction, that can make code cleaner and avoid following race:

• Updater A called vos_obj_hold(), it failed to find the OI and mark the obj entry in ts_set as negative.
• Updater A yield.
• Concurrent updater B created OI and setup obj->obj_df.
• Updater A resumed to call vos_obj_incarnate(), it found that the obj->obj_df is non-NULL so skipped OI creation.
• The ts_set for updater A is now in an inconsistent state, it's negative but without 'se_create_idx' set.

Steps for the author:

• Commit message follows the guidelines.
• Appropriate Features or Test-tag pragmas were used.
• Appropriate Functional Test Stages were run.
• At least two positive code reviews including at least one code owner from each category referenced in the PR.
• Testing is complete. If necessary, forced-landing label added and a reason added in a comment.

After all prior steps are complete:

• Gatekeeper requested (daos-gatekeeper added as a reviewer).

[github-actions]

Ticket title is 'mdonssd phase 2: Assertion 'set_entry->se_create_idx != NULL' failed'
Status is 'In Progress'
Labels: 'md_on_ssd2,test_2.8'
https://daosio.atlassian.net/browse/DAOS-18531

[daosbuild3]

Test stage Unit Test on EL 8.8 completed with status UNSTABLE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net/job/daos-stack/job/daos//view/change-requests/job/PR-17501/1/testReport/

[daosbuild3]

Test stage Unit Test with memcheck on EL 8.8 completed with status UNSTABLE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net/job/daos-stack/job/daos//view/change-requests/job/PR-17501/1/testReport/

[daosbuild3]

Test stage NLT on EL 8.8 completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-17501/1/execution/node/790/log

[daosbuild3]

Test stage NLT on EL 8.8 completed with status UNSTABLE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net/job/daos-stack/job/daos//view/change-requests/job/PR-17501/2/testReport/

[daosbuild3]

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[daosbuild3]

Test stage Functional on EL 8.8 completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-17501/2/execution/node/1066/log

[daosbuild3]

Test stage NLT on EL 8.8 completed with status UNSTABLE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net/job/daos-stack/job/daos//view/change-requests/job/PR-17501/3/testReport/

[daosbuild3]

Test stage Functional Hardware Medium Verbs Provider MD on SSD completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-17501/3/execution/node/1343/log

[Nasf-Fan]

It is better to add comment to explain when need to call vos_obj_hold() and when to call vos_obj_acquire(). As my understand, with your patch, for modification, the logic needs to call vos_obj_acquire() + vos_obj_incarnate(); otherwise, non-transactional operations will use vos_obj_hold(). If that is true, some logic inside vos_obj_hold() (for modification) can be removed, and maybe we can rename related functions to help understanding.

[NiuYawei]

It is better to add comment to explain when need to call vos_obj_hold() and when to call vos_obj_acquire(). As my understand, with your patch, for modification, the logic needs to call vos_obj_acquire() + vos_obj_incarnate(); otherwise, non-transactional operations will use vos_obj_hold(). If that is true, some logic inside vos_obj_hold() (for modification) can be removed, and maybe we can rename related functions to help understanding.

Sure, I can add some comments. My plan is to gradually deprecate the vos_obj_hold(), but let's postpone the code cleanup work after 2.8.