[libvirt] [PATCH] qemu: domain: Replace qemuDomainFilePathIsHostCDROM with virFileIsCDROM

[Peter Krempa]

On Mon, May 07, 2018 at 13:13:42 -0400, Laine Stump wrote:
> On 05/07/2018 11:21 AM, Peter Krempa wrote:
> > Use the new helper when checking that the VM needs to be tainted as a
> > host-cdrom passthrough.
> >
> > Signed-off-by: Peter Krempa <pkrempa at redhat.com>
> > ---
> >  src/qemu/qemu_domain.c | 31 +------------------------------
> >  1 file changed, 1 insertion(+), 30 deletions(-)
> >
> > diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> > index b13e6d8ca4..ec865e68c8 100644
> > --- a/src/qemu/qemu_domain.c
> > +++ b/src/qemu/qemu_domain.c
> > @@ -6483,35 +6483,6 @@ qemuDomainDefFormatLive(virQEMUDriverPtr driver,
> >  }
> >
> >
> > -/* qemuDomainFilePathIsHostCDROM
> > - * @path: Supplied path.
> > - *
> > - * Determine if the path is a host CD-ROM path. Typically this is
> > - * either /dev/cdrom[n] or /dev/srN, so those are easy checks, but
> > - * it's also possible that @path resolves to /dev/srN, so check for
> > - * those conditions on @path in order to emit the tainted message.
> > - *
> > - * Returns true if the path is a CDROM, false otherwise or on error.
> > - */
> > -static bool
> > -qemuDomainFilePathIsHostCDROM(const char *path)
> > -{
> > -    bool ret = false;
> > -    char *linkpath = NULL;
> > -
> > -    if (virFileResolveLink(path, &linkpath) < 0)
> > -        goto cleanup;
> > -
> > -    if (STRPREFIX(path, "/dev/cdrom") || STRPREFIX(path, "/dev/sr") ||
> > -        STRPREFIX(linkpath, "/dev/sr"))
> > -        ret = true;
> > -
> > - cleanup:
> > -    VIR_FREE(linkpath);
> > -    return ret;
> > -}
> > -
> > -
> >  void qemuDomainObjTaint(virQEMUDriverPtr driver,
> >                          virDomainObjPtr obj,
> >                          virDomainTaintFlags taint,
> > @@ -6630,7 +6601,7 @@ void qemuDomainObjCheckDiskTaint(virQEMUDriverPtr driver,
> >
> >      if (disk->device == VIR_DOMAIN_DISK_DEVICE_CDROM &&
> >          virStorageSourceGetActualType(disk->src) == VIR_STORAGE_TYPE_BLOCK &&
> > -        disk->src->path && qemuDomainFilePathIsHostCDROM(disk->src->path))
> > +        disk->src->path && virFileIsCDROM(disk->src->path))
> >          qemuDomainObjTaint(driver, obj, VIR_DOMAIN_TAINT_CDROM_PASSTHROUGH,
> >                             logCtxt);
> >
> 
> Not a 1 for 1 replacement of code, so possible behavior may change in
> some odd circumstance, but if it does, that's probably a *good* thing
> since the new function is more accurate.
> 
> However, virFileIsCDROM() returns different values than
> qemuDomainFilePathIsHostCDROM(). In particular, it can fail and return
> -1. The other use of virFileCDRom compares with 1 (meaning that
> "failure" is the same as "not a CDROM"), but here you're just checking
> for T/F, so "failure" == "*is* a CDROM.

You are right, in this case we should treat it the same. I'll change it.

> 
> 
> I won't attempt to say which is the better behavior, but I'd venture it
> should be consistent. Once you've fixed that (or with a short
> explanation in the commit message of why you treated the two uses
> differently):
> 
> 
> Reviewed-by: Laine Stump <laine at laine.org>

Thanks!
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