On Mon, Mar 30, 2020 at 06:16:29PM +0200, Michal Prívozník wrote: > On 30. 3. 2020 13:09, Daniel P. Berrangé wrote: > > On Thu, Mar 26, 2020 at 04:15:06PM +0100, Michal Privoznik wrote: > >> Initially introduced in v3.10.0-rc1~172. > >> > >> When generating a path for memory-backend-file or -mem-path, qemu > >> driver will use the following pattern: > >> > >> $memoryBackingDir/libvirt/qemu/$id-$shortName > >> > >> where $memoryBackingDir defaults to /var/lib/libvirt/qemu/ram but > >> can be overridden in qemu.conf. Anyway, the "/libvirt/qemu/" part > >> looks redundant, because it's already contained in the default, > >> or creates unnecessary nesting if overridden in qemu.conf. > > > > I think this was copied from our earlier huge pages code > > which used /dev/hugepages, and then added "/libvirt/qemu" > > to it. > > > > Now we're stripping off "/libvirt/qemu" though, we're liable > > to a filename clashes if someone edits qemu.conf to point to > > /dev/shm. > > > > IOW, even though "/libvirt/qemu" is redundant when using our > > default path, I think we need to keep it to avoid clashing > > with custom paths. > > Alright. So what if I'd squash this in? > > diff --git i/src/qemu/qemu_conf.c w/src/qemu/qemu_conf.c > index 9786e19f8f..2ead5d5920 100644 > --- i/src/qemu/qemu_conf.c > +++ w/src/qemu/qemu_conf.c > @@ -970,7 +970,18 @@ static int > virQEMUDriverConfigLoadMemoryEntry(virQEMUDriverConfigPtr cfg, > virConfPtr conf) > { > - return virConfGetValueString(conf, "memory_backing_dir", &cfg->memoryBackingDir); > + char *dir = NULL; > + int rc; > + > + if ((rc = virConfGetValueString(conf, "memory_backing_dir", &dir)) < 0) { > + return -1; > + } else if (rc > 0) { > + VIR_FREE(cfg->memoryBackingDir); > + cfg->memoryBackingDir = g_strdup_printf("%s/libvirt/qemu", dir); > + return 1; > + } > + > + return 0; > } > > > This way we would drop "/libvirt/qemu" in the default configuration and keep it if user overrides it in qemu.conf. Yeah, I think that works. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|