Re: [libvirt] [PATCH 2/2] storage: Forbid wiping formatted volume types that are not supported
On Thu, Jul 14, 2016 at 02:27:41PM +0200, Martin Kletzander wrote:
Until now we allowed that to happen, however the only thing we
supported
was either rewiting the file or truncating it. That however doesn't
keep the format of that file, so QCOWs, VDIs and all others just became
RAW with arbitrary size.
Yes, wiping wipes the format as well. Nothing wrong with that.
Not to mention any domain using such volume
could not start anymore. Instead of dealing with the recreation of
every single possible file that we have (and possibly failing due to
create_tool capabilities) just forbid it for now.
We even state in our
documentation that it has no value for file-backed volumes.
Where?
Also note, that depending on the actual volume representation, this call
may not really overwrite the physical location of the volume. For
instance, files stored journaled, log structured, copy-on-write,
versioned, and network file systems are known to be problematic.
http://libvirt.org/html/libvirt-libvirt-storage.html#virStorageVolWipe
This only says that it might not work, not that it's completely useless.
I think we have a precedent for supporting marginally useful features by
still supporting qcow encryption.
NACK to breaking functionality in order to resolve a 4-year-old
synthetic QE-filed bug.
I suggest WONTFIX or NOTABUG.
Jan