Re: [Qemu-block] [PATCH v2 1/2] qemu-img: Resolve relative backing paths in rebase

[Eric Blake]

On 05/09/2018 01:20 PM, Max Reitz wrote:
> Currently, rebase interprets a relative path for the new backing image
> as follows:
> (1) Open the new backing image with the given relative path (thus relative to
>      qemu-img's working directory).
> (2) Write it directly into the overlay's backing path field (thus
>      relative to the overlay).
>
> If the overlay is not in qemu-img's working directory, both will be
> different interpretations, which may either lead to an error somewhere
> (either rebase fails because it cannot open the new backing image, or
>   your overlay becomes unusable because its backing path does not point
>   to a file), or, even worse, it may result in your rebase being
> performed for a different backing file than what your overlay will point

Interesting indentation in this paragraph. A maintainer could tweak it.

> to after the rebase.
>
> Fix this by interpreting the target backing path as relative to the
> overlay, like qemu-img does everywhere else.
>
> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1569835
> Cc: address@hidden
> Signed-off-by: Max Reitz <address@hidden>
> ---
>   qemu-img.c | 23 ++++++++++++++++++++++-
>   1 file changed, 22 insertions(+), 1 deletion(-)

Reviewed-by: Eric Blake <address@hidden>

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org