Re: [libvirt] [PATCH] qemu: Fix a regression of attaching device

On 07/13/2011 09:17 AM, Osier Yang wrote: > qemuDomainModifyDeviceFlags: Changing "ret" to "0", but don't > reset it to "-1" on failure, it's not good idea to change the value > of "ret" in the codes to do some condition checking. This patch > fix it. Can you identify which commit introduced the regression, and what behavior actually broke as a result? The commit message will be more useful with that information. > --- > src/qemu/qemu_driver.c | 6 +++--- > 1 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c > index 0a6b48e..ae11c68 100644 > --- a/src/qemu/qemu_driver.c > +++ b/src/qemu/qemu_driver.c > @@ -4892,10 +4892,10 @@ qemuDomainModifyDeviceFlags(virDomainPtr dom, const char *xml, > _("unknown domain modify action %d"), action); > break; > } > - } else > - ret = 0; > + } > > - if (!ret&& (flags& VIR_DOMAIN_AFFECT_LIVE)) { > + if (!(flags& VIR_DOMAIN_AFFECT_CONFIG)&& > + (flags& VIR_DOMAIN_AFFECT_LIVE)) { I'm not sure I agree with this change. The logic flow before this patch is: if config make the change in a copy, or record that the change failed if live, and either no config or change to config copy is happy make the change live, or record that change failed if config, and either no live or change to live is happy commit the changed copy made earlier Your proposed change makes it so that we can now change live even if we are going to fail to change the config, which is not a good idea.

Why not instead do: if config { make change in a copy if ret< 0 goto error } if live { make change in live if ret< 0 goto error } if config commit the changed copy made earlier