Max Reitz <mre...@redhat.com> writes: > On 2014-11-28 at 16:43, Markus Armbruster wrote: >> Kevin Wolf <kw...@redhat.com> writes: >> >>> Am 20.11.2014 um 13:44 hat Max Reitz geschrieben: >>>> The 'change' QMP and HMP command allows replacing the medium in drives >>>> which support this, e.g. floppy disk drives. For some drives, the medium >>>> carries information about whether it can be written to or not (again, >>>> floppy drives). Therefore, it should be possible to change the read-only >>>> state of block devices when changing the loaded medium. >>>> >>>> This series adds an optional additional parameter to the 'change' QMP >>>> and HMP command which allows changing the read-only state in four ways: >>>> >>>> - 'retain': Just keep the status as it was before; this is the current >>>> behavior and thus this will be the default. >>>> - 'ro': Force read-only access >>>> - 'rw': Force writable access >>>> - 'auto': This opens the new file R/W first, if that fails, the file is >>>> opened read-only. >>> Not sure if 'auto' is worth implementing (it's a typical HMP default >>> action that no QMP client would use, except that it isn't even the >>> default for HMP), but the implementation looks correct at least. >> QMP eschews magic. I'd prefer to keep 'auto' out. >> >> HMP can offer it regardless, if it's useful. But I doubt it will be. >> Few users will need to control this, and fewer will realize they can by >> giving an extra argument. > > Well, Kevin made the good point of the user generally knowing whether > a file should be written to or not. Furthermore, I don't think it > would be too hard to use rw, then see that access was denied, and then > use ro, manually. Maybe that's even better than auto, somehow.
Please give it a try.
