block: Keep track of devices' I/O status
commit28a7282a5d5a15527e66d3a93c93c4ccc292f694
authorLuiz Capitulino <lcapitulino@redhat.com>
Mon, 26 Sep 2011 20:43:50 +0000 (26 17:43 -0300)
committerKevin Wolf <kwolf@redhat.com>
Tue, 11 Oct 2011 07:41:47 +0000 (11 09:41 +0200)
tree423bbb87fff9eb708c120e8b791cd69d0c78278d
parent449c184ed23c6238da7fcc8b965c8fcc865d72a9
block: Keep track of devices' I/O status

This commit adds support to the BlockDriverState type to keep track
of devices' I/O status.

There are three possible status: BDRV_IOS_OK (no error), BDRV_IOS_ENOSPC
(no space error) and BDRV_IOS_FAILED (any other error). The distinction
between no space and other errors is important because a management
application may want to watch for no space in order to extend the
space assigned to the VM and put it to run again.

Qemu devices supporting the I/O status feature have to enable it
explicitly by calling bdrv_iostatus_enable() _and_ have to be
configured to stop the VM on errors (ie. werror=stop|enospc or
rerror=stop).

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.

Next commits will add support to some devices and extend the
query-block/info block commands to return the I/O status information.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block.c
block.h
block_int.h
monitor.c