Re: [libvirt] [PATCH 4/4] logical: Adjust regex for devices

... >> >> However, after some more "investigation" of the environment - I think >> perhaps there's still a couple of loose ends. Keeping the 'segtype' >> field may be necessary/useful... Details follow if interested ;-) > > Yes, you're right and I did a bad job during review. The segtype is required > and we should always consider it, there is like 20 segtypes right now and some > of them could also use 'stripes'. > The 'segtype' is currently only required because commit id '82c1740a' added 'segtype' and 'stripes' to resolve a bz (or more than one depending on how far you chase) by using 'segtype' to determine whether more than one existed. It also did quite a few things in one step which by today's review standards is a bad thing ;-). However, that only worked for "striped" lv's. If there was a "mirror" lv, then while the mirror could be found, the vol-dumpxml output is wrong because it only parsed 1 extent (incorrectly at that):

<source> <device path='lv_test_mirror_rimage_0(0),lv_test_mirror_rimage_1'> <extent start='0' end='33554432'/> </device> </source> instead of something like (if using 'stripes' to get nsegments): <source> <device path='lv_test_mirror_rimage_0'> <extent start='0' end='33554432'/> </device> <device path='lv_test_mirror_rimage_1'> <extent start='0' end='33554432'/> </device> </source> Linking 'nsegments' to 'striped' lv's is a "limitation". Anyway, dropping 'segtype' wasn't necessarily bad unless you needed "more information", such as perhaps the lv thin pool source when nsegments == 0. This becomes obvious once the change to use "(\\S*)" instead of "(\\S+)" hits. Now we can "see" thin lv's in a volume group. Not sure what else becomes visible, though. The problem is you then get:

<source> </source> But that's fixable... The interesting part about <source> is that it's an output only (virStorageVolDefParseXML doesn't read it). So, by adding a new parse field 'pool_lv', we can then check 'segtype' to be "thin" and if so, store the new field in a new vol->source.thin_pool field. Still cannot create a thin lv pool/volume without using the lvcreate command. Nor can one create a mirror or stripe lv using libvirt's vol-create command. One just cannot "find" a thin lv right now... John