[LU-11456] MDT can skip sync if the object is synced yet

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.13.0
• Affects Version/s: Upstream
• Assignee: Alex Zhuravlev
• Reporter: Alex Zhuravlev

Description

mdt_object_sync() can skip sync if the version stored in the object is declared committed

Comments

[Peter Jones]

Landed for 2.13

[Gerrit Updater]

Oleg Drokin ([e-mail]) merged in patch https://review.whamcloud.com/33266/
Subject: LU-11456 mdt: mdt_object_sync() can skip sync
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 2291c21d174ac0a88f2c3b0551362079c963df16

[Alex Zhuravlev]

created LU-11462 to track ZFS-specific solution.

[Alex Zhuravlev]

yes, I think we can improve this a bit more as each OSD could check whether specific state has been already sent to disk and skip another skip just waiting for the previous one to complete.
at least for ZFS this is relatively easy, need to think about ldiskfs..

[Andreas Dilger]

I also see in the osd-zfs code:

static int osd_object_sync(const struct lu_env *env, struct dt_object *dt,
                           __u64 start, __u64 end)
{
        struct osd_device *osd = osd_obj2dev(osd_dt_obj(dt));
        ENTRY;
        
        /* XXX: no other option than syncing the whole filesystem until we
         * support ZIL.  If the object tracked the txg that it was last
         * modified in, it could pass that txg here instead of "0".  Maybe
         * the changes are already committed, so no wait is needed at all? */
        if (!osd->od_dt_dev.dd_rdonly) {
                if (osd_object_sync_delay_us < 0)
                        txg_wait_synced(dmu_objset_pool(osd->od_os), 0ULL);
                else
                        udelay(osd_object_sync_delay_us);
        } 
         
        RETURN(0);
}

[Gerrit Updater]

Alex Zhuravlev ([e-mail]) uploaded a new patch: https://review.whamcloud.com/33266
Subject: LU-11456 mdt: mdt_object_sync() can skip sync
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 03d8b8f3eb66c839041176e4f3149de4811f88c1