On 05.09.2014 16:40, Eric Blake wrote:
On 09/05/2014 08:07 AM, Max Reitz wrote:
Not every BLOCK_IMAGE_CORRUPTED event must be fatal; for example, when
reading from an image, they should generally not be. Nonetheless, even
an image only read from may of course be corrupted and this can be
detected during normal operation. In this case, a non-fatal event should
be emitted, but the image should not be marked corrupt (in accordance to
"fatal" set to false).
Question - what happens if management misses the signal? For example,
if libvirt opens qemu on a read-only image, then goes away, then
corruption is detected, then libvirt reconnects. Does query-block need
to also be updated to report whether a read-only BDS is currently
detected as fatal, but that an event has already been delivered?
Well, the obvious problem with that is that corruption currently is a
strongly format-specific topic, and only reported for qcow2. So, to do
this, we'd have to move the corruption signalling code into the common
block layer functions and proceed from there. This actually probably
isn't too bad of an idea, anyway. But then we'll need a global
bdrv_mark_corrupt() function (which we probably don't want in case we
get more flags in the future, so we'll rather want bdrv_set_flag() or
something) and I don't really want to make these changes now... We could
postpone this, though. Making this change later shouldn't break anything.
The other solution would be simply to suppress the stderr message but to
always deliver the QMP event.