On Tue, 2016-06-28 at 16:07 -0400, Mike Snitzer wrote: > On Tue, Jun 28 2016 at 3:37pm -0400, > Toshi Kani <toshi.kani@xxxxxxx> wrote: : > You said in the 0th header: "Patch 1 solves an error when lvremove is > made to a snapshot device." > > I'm not seeing why this patch 1 fixes anything specific to snapshot > device removal (but I can see why patch 2 makes snapshot creation > "work"). I'll apply your 2nd patch and see if I can see what you mean. > > I actually see this error, without either of your 2 proposed patches > applied, when I try to create a snapshot of a DAX capable LV: > > # lvcreate -s -n snap -L 100M pmem/lv > device-mapper: reload ioctl on (253:7) failed: Invalid argument > Failed to lock logical volume pmem/lv. > Aborting. Manual intervention required. > Jun 28 15:57:28 rhel-storage-02 kernel: device-mapper: ioctl: can't change > device type after initial table load. Yes, patch 2 fixes this error. I have not looked into why lvremove does this, but lvremove to a snapshot device fails to reload DM table of "<dev>-lvsnap" device (which is marked as DM_TYPE_BIO_BASED) with DM_TYPE_DAX_BIO_BASED. Patch 1 fixes this error. I think it also generally makes sense to allow this case. Thanks, -Toshi -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
