Kevin Wolf <kw...@redhat.com> writes:
> Am 09.08.2011 13:56, schrieb Markus Armbruster:
>> bdrv_is_locked() is about the frontend's media lock. To make this more
>> obvious, my PATCH 29/55 replaces it by bdrv_dev_is_medium_locked(). It
>> does *not* query the backend's lock (which may not even exist!) set by
>> bdrv_set_locked().
>
> This sounds wrong (the behaviour, not your analysis). Do you plan to
> remove bdrv_dev_is_medium_locked() as well? It is used by IDE and
> scsi-disk (easy to replace) and in eject_device() in blockdev.c. Maybe
> the 'eject' monitor command should be handled by another callback into
> the device.
Just two users remain after my series:
* bdrv_info()
It wants to show the frontend's lock state, and uses
bdrv_dev_is_medium_locked() to get it from the frontend.
* eject_device()
It needs to fail if the frontend has its medium locked. It uses
bdrv_dev_is_medium_locked() to get the lock state from the frontend.
Pseudo code (-f glossed over for simplicity):
unless frontend has removable media
fail
if frontend medium is not already open
and frontend medium is locked
fail
drop the block driver
I considered replacing this with "ask the frontend to eject", and then
let the frontend decide whether to order the backend to drop the block
driver. I decided against it, since I need
bdrv_dev_is_medium_locked() anyway for bdrv_info(). Besides, the
series is long enough already.
