Am 03.05.2016 um 12:49 hat Max Reitz geschrieben: > On 02.05.2016 17:35, Kevin Wolf wrote: > > Am 26.04.2016 um 23:32 hat Max Reitz geschrieben: > >> If the backing file is overridden, this most probably does change the > >> guest-visible data of a BDS. Therefore, we will need to consider this in > >> bdrv_refresh_filename(). > >> > >> Adding a new field to the BDS is not nice, but it is very simple and > >> exactly keeps track of whether the backing file has been overridden. > >> > >> Signed-off-by: Max Reitz <mre...@redhat.com> > > > > What about live snapshots or block jobs that manipulate bs->backing? > > They don't use bdrv_open_backing_file(), but bdrv_append() or > > bdrv_replace_in_backing_chain() in order to assign a backing file, which > > may or may not be the same as in the image header. > > I'll take a look into each case, thanks. > > > Also, do we want to consider a backing file overridden when the user > > specified it explicitly, but it matches the image header? > > For simplicity's sake, I would. I think we've realized before that > trying to identify whether to file names point to the same image is > rather difficult.
I was just asking because in that case, we probably must consider things like the backing file of a live snapshot overlay overridden as well (at least when using an existing image). Kevin
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