[pve-devel] [PATCH v2 qemu-server] Fix block_resize qmp call for block devices

[Dmitry Petuhov]

12.01.2017 16:18, Fabian Grünbichler пишет:
> On Thu, Jan 12, 2017 at 03:33:48PM +0300, Dmitry Petuhov wrote:
>> Set zero size for backing block devices in qmp call. In that case qemu
>> sets size of device in guest to current size of backing device, which
>> was resized earlier. Otherwise, any non-zero value causes error here.
> this is not clearly documented, but if PVE::Storage::volume_resize
> returns 1, we assume the storage layer did not resize and qemu should do
> the resizing
>
> if it returns undef, we assume the storage resized the volume and we are
> done.
There's problem: even if storage has resized blockdev, this change is 
not propagated to running qemu until we send block_resize to it.
So we need to resize BOTH in storage AND in qemu.

> so in the latter case, instead of returning in line 3983 we could set
> $size to 0 (based on the return code of course ;)) and continue with the
> running check and block_resize via monitor. this should only improve the
> situation for all storages, without any wonky checks based on block
> device or not.
ZFS plugins are showing interesting behaviour here: return $new_size;
Maybe we could do that in all plugins, that support resizing and just
$size = PVE::Storage::volume_resize($storecfg, $volid, $size, $running);
and then continue with any defined value (includig 0)?