Re: [Qemu-devel] [PATCH v3 1/1] dump.c: allow fd_write_vmcore to return errno on failure

[Eric Blake]

On 02/12/2018 08:25 AM, Daniel Henrique Barboza wrote:
> From: Yasmin Beatriz <address@hidden>
>
> fd_write_vmcore can fail to execute for a lot of reasons that can be
> retrieved by errno, but it only returns -1. This makes difficult for
> the caller to know what happened and only a generic error message is
> propagated back to the user. This is an example using dump-guest-memory:
>
> (qemu) dump-guest-memory /home/yasmin/mnt/test.dump
> dump: failed to save memory
...
> This is the same dump-guest-memory example with this patch applied:
>
> (qemu) dump-guest-memory /home/yasmin/mnt/test.dump
> dump: failed to save memory: No space left on device
> (qemu)
>
> This example illustrates an error of fd_write_vmcore when called
> from write_data. All other callers will benefit from better
> error messages as well.
>
> Reported-by: address@hidden
> Cc: Jose Ricardo Ziviani <address@hidden>
> Signed-off-by: Yasmin Beatriz <address@hidden>
> Signed-off-by: Daniel Henrique Barboza <address@hidden>
> ---
>   dump.c | 23 ++++++++++++++---------
>   1 file changed, 14 insertions(+), 9 deletions(-)

Reviewed-by: Eric Blake <address@hidden>

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