Re: [libvirt] [PATCH v2] storage: vz storage pool support
On 12/16/2016 06:14 AM, Olga Krishtal wrote:
On 08/12/16 22:56, John Ferlan wrote:
>>> Compare that to NFS, which uses mount which is included in well every
>>> distro I can think of. That's a big difference. Also let's face it,
NFS
>>> has been the essential de facto goto tool to access remote storage
>>> for a
>>> long time. Personally, I'd rather see the NFS code split out of the
>>> *_fs.c backend, but I don't have the desire/time to do it - so it stays
>>> as is.
>> To sum this up, you still think that copy and paste isn't a problem here
>> and will create more value than do any harm, right?
>>
> Not sure what you're inferring by copy and paste - other than perhaps
> having to decide for the vstorage backend which storage backend API's it
> needs or should support.
>
> The list of API's as I see from the path are:
>
> +
> + .startPool = virStorageBackendVzStart,
> + .checkPool = virStorageBackendFileSystemCheck,
> + .stopPool = virStorageBackendFileSystemStop,
> + .findPoolSources = virStorageBackendVzfindPoolSources,
> + .buildPool = virStorageBackendFileSystemBuild,
> + .deletePool = virStorageBackendFileSystemDelete,
> + .refreshPool = virStorageBackendFileSystemRefresh,
> + .buildVol = virStorageBackendFileSystemVolBuild,
> + .buildVolFrom = virStorageBackendFileSystemVolBuildFrom,
> + .createVol = virStorageBackendFileSystemVolCreate,
> + .refreshVol = virStorageBackendFileSystemVolRefresh,
> + .deleteVol = virStorageBackendFileSystemVolDelete,
> + .resizeVol = virStorageBackendFileSystemVolResize,
> + .uploadVol = virStorageBackendVolUploadLocal,
> + .downloadVol = virStorageBackendVolDownloadLocal,
> + .wipeVol = virStorageBackendVolWipeLocal,
> +
>
> Other than startPool and findPoolSources, the code will reuse/call the
> virStorageBackendFileSystem* API's - so the only copy/paste would be
> copyrights, some #include's that would be required only for vstorage,
> the VIR_FROM_THIS definition, VIR_LOG_INIT... Nothing any other backend
> wouldn't have to do.
By reusing you mean to export virStorageBackendFileSystem* and call
them from
staorage_backen_vstorage?
Otherwise, may be I could do vstorage stuff only under #ifdef without
touching any of
virStorageBackendFileSystem* ?
I can see why the desire is to use storage_backend_fs because it already
has a bunch of things you'll need, so I understand why it's desired to
be included there.
From the other POV though - the more #ifdef code in storage_backend_fs
the 'harder' it is to separate things (conceptually).
Finally, I also have floating around is the fspool adjustments and
wonder what kind of overlap exists.
Still seeing progress is good too and I guess unless I or someone else
volunteers to split up storage_backend_fs.c into multiple backends (fs,
nfs, dir, etc.) I guess we're stuck with what we have.
John
> Although I do question "checkPool" - I would think for
vstorage that
> should check if the environment is "available" somehow *if* you want
> pool autostart
Thanks, you are right.
>
> Also for stopPool the code will essentially call unmount. So is that
> "expected" for vstorage?
yes, just umount.
>
> Going through each API callout is how you'll be able to tell me/us that
> taking that path will work for the vstorage environment.
>
> John