[Qemu-devel] query-block io-status display

[Jack Schwartz]

Hi Luiz, Markus and everyone.

I am working on a qemu enhancement to display io-status in each 
query-block command, not just those for devices which have werror and/or 
rerror set to stop on error.

I'd like to verify the reasons behind the query-block command not 
reporting io-status if errors were reported to the guest or ignored.  A 
clue may come from the original code review email[1] for when this code 
was implemented:

  "In case of multiple errors being triggered in sequence only the first
   one is stored. The I/O status is always reset to BDRV_IOS_OK when the
   'cont' command is issued."

From this I infer:
- io-status is shown when qemu is stopped onerror so errors can be seen 
in cases where a guest does not handle them.
- io-status is not shown when errors are already being handled by a guest
- io-status is not shown when errors are ignored

Is this correct?  Are there other subtleties/reasons as well?

    Thanks,
    Jack

[1] http://lists.nongnu.org/archive/html/qemu-devel/2011-09/msg02940.html