On 11/17/20 11:45 PM, David Teigland wrote: > On Tue, Nov 17, 2020 at 11:52:28AM +0800, heming.zhao@xxxxxxxx wrote: >> In lvm functions, it treats "return 0" as error case. >> >> if _lvchange_activate() return ECMD_FAILED, the caller _lvchange_activate_single() think as normal: >> ``` >> if (!_lvchange_activate(cmd, lv)) <== ECMD_FAILED is 5, won't enter if case. >> return_ECMD_FAILED; > > Thanks for finding that. In some places 0 is the error value and in other > places ECMD_FAILED is the error value; they frequently get mixed up. > I believe this is the bug you are seeing: > https://sourceware.org/git/?p=lvm2.git;a=commit;h=aba9652e584b6f6a422233dea951eb59326a3de2 > I recommend to use a define (e.g. E_COMM_ERR) not magic number (ZERO) to replace return value. >> 2. node2 change the systemid to itself >> >> ``` >> [tb-clustermd2 ~]# vgchange -y --config "local/extra_system_ids='tb-clustermd1'" --systemid tb-clustermd2 vg1 >> Volume group "vg1" successfully changed >> [tb-clustermd2 ~]# lvchange -ay vg1/lv1 >> [tb-clustermd2 ~]# dmsetup ls >> vg1-lv1 (254:0) > > This is what the LVM-activate resource agent does, except it wouldn't be > done while the LV is active on another running host. Just wanted to > clarify that, I don't think it's the point of your illustration here. > >> 3. this time both sides have dm device. >> ``` >> [tb-clustermd1 ~]# dmsetup ls >> vg1-lv1 (254:0) >> [tb-clustermd2 ~]# dmsetup ls >> vg1-lv1 (254:0) >> ``` > > For the sake of anyone looking at this later, this shouldn't happen in a > properly running cluster. (If you wanted the LV active on two hosts at > once, you'd use lvmlockd and no system ID on the VG.) > >> 4. node1 executes lvchange cmds. please note the return value is 0 >> ``` >> [tb-clustermd1 ~]# lvchange -ay vg1/lv1 ; echo $? >> WARNING: Found LVs active in VG vg1 with foreign system ID tb-clustermd2. Possible data corruption. >> Cannot activate LVs in a foreign VG. >> 0 > > That's the one fixed by the commit above. > > Dave > _______________________________________________ linux-lvm mailing list linux-lvm@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
