On Tue, Oct 14, 2025 at 10:50:31AM +0200, Kevin Wolf wrote:
> Am 08.10.2025 um 17:55 hat Eric Blake geschrieben:
> > > > Also not sure whether we should add "nbd" to the "formats" list - it's a
> > > > protocol, and not a format, isn't it?
> > > 
> > > Yes, technically there are two distinct axis  formats vs protocols, but
> > > from the POV of running the 'check' script the boundary is rather blurred.
> > > 
> > > You can run './check -nbd' and './check -qcow2', or both combined. The 
> > > main
> > > limit that you can only pick a single format and single protocol at a 
> > > time.
> > 
> > In fact, I've seen times where './check -nbd -raw' passes but './check
> > -nbd -qcow2' fails, because that combination enables different sets of
> > tests.  So we probably STILL aren't giving CI everything possible to
> > test by having just one dimension of easy-to-name test subsets, but it
> > is still better than no CI nbd tests at all.
> 
> How valid is -nbd -qcow2 even? Wasn't there the fundamental problem that
> NBD devices can't grow?

There are some tests that run differently under '-nbd -qcow2' than
under '-nbd -file'; but you are also correct that any qcow2 test that
relies on image resizing can't work with nbd.

> 
> Running various image formats may be useful for other protocols, but I'm
> not sure that NBD is one of them.
> 
> > > IMHO for test suites it is preferrable to keep a flat namespace, rather
> > > than creating a matrix of suites for protocol vs format combniations.
> > > 
> > > Perhaps the meson.build variable should just be renamed from _formats
> > > to something else.
> > 
> > Renaming makes sense to me; would _bds be a reasonable name (since
> > both protocols and formats are a BDS)?  I'm open to other naming
> > ideas, as well.
> 
> Well, bdrv if anything (block driver rather than BlockDriverState).

Yeah, that does sound better...

> 
> But we also have -fuse, which isn't really a block driver, but it just
> means that we're using the file protocol on top of a FUSE export...
> 
> Probably not worth renaming from one imperfect name to another imperfect
> one.

...but I'm not opposed to inertia sticking to a slightly inaccurate
name over the pain of churn just to change the name.  It's not
something that Coccinelle can automate.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.
Virtualization:  qemu.org | libguestfs.org


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