• M
    block: Change bdrv_eject() not to drop the image · 4be9762a
    Markus Armbruster 提交于
    bdrv_eject() gets called when a device model opens or closes the tray.
    
    If the block driver implements method bdrv_eject(), that method gets
    called.  Drivers host_cdrom implements it, and it opens and closes the
    physical tray, and nothing else.  When a device model opens, then
    closes the tray, media changes only if the user actively changes the
    physical media while the tray is open.  This is matches how physical
    hardware behaves.
    
    If the block driver doesn't implement method bdrv_eject(), we do
    something quite different: opening the tray severs the connection to
    the image by calling bdrv_close(), and closing the tray does nothing.
    When the device model opens, then closes the tray, media is gone,
    unless the user actively inserts another one while the tray is open,
    with a suitable change command in the monitor.  This isn't how
    physical hardware behaves.  Rather inconvenient when programs
    "helpfully" eject media to give you a chance to change it.  The way
    bdrv_eject() behaves here turns that chance into a must, which is not
    what these programs or their users expect.
    
    Change the default action not to call bdrv_close().  Instead, note the
    tray status in new BlockDriverState member tray_open.  Use it in
    bdrv_is_inserted().
    
    Arguably, the device models should keep track of tray status
    themselves.  But this is less invasive.
    Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
    Signed-off-by: NKevin Wolf <kwolf@redhat.com>
    4be9762a
block_int.h 9.3 KB