From 2e4357c537287edd47d6031fec8bffc7b0ce2425 Mon Sep 17 00:00:00 2001 From: Fiona Ebner Date: Fri, 28 Apr 2023 14:32:07 +0200 Subject: [PATCH] block resize: avoid passing zero size to QMP command Commit 7246e8f9 ("Set zero $size and continue if volume_resize() returns false") mentions that this is needed for "some storages with backing block devices to do online resize" and since this patch came together [0] with pve-storage commit a4aee43 ("Fix RBD resize with krbd option enabled."), it's safe to assume that RBD with krbd is meant. But it should be the same situation for any external plugin relying on the same behavior. Other storages backed by block devices like LVM(-thin) and ZFS return 1 and the new size respectively, and the code is older than the above mentioned commits. So really, the RBD plugin just should have returned a positive value to be in-line with those and there should be no need to pass 0 to the block_resize QMP command either. Actually, it's a hack, because the block_resize QMP command does not actually do special handling for the value 0. It's just that in the case of a block device, QEMU won't try to resize it (and not fail for shrinkage). But the size in the raw driver's BlockDriverState is temporarily set to 0 (which is not nice), until the sector count is refreshed, where raw_co_getlength is called, which queries the new size and sets the size in the raw driver's BlockDriverState again as a side effect. It's not known to cause any issues, but bdrv_getlength is a coroutine wrapper starting from QEMU 8.0.0, and it's just better to avoid setting a completely wrong value even temporarily. Just pass the actually requested size like is done for LVM(thin) and ZFS. [0]: https://lists.proxmox.com/pipermail/pve-devel/2017-January/025060.html Signed-off-by: Fiona Ebner --- PVE/QemuServer.pm | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm index f0c35ceb..33b7c537 100644 --- a/PVE/QemuServer.pm +++ b/PVE/QemuServer.pm @@ -4768,7 +4768,7 @@ sub qemu_block_resize { my $running = check_running($vmid); - $size = 0 if !PVE::Storage::volume_resize($storecfg, $volid, $size, $running); + PVE::Storage::volume_resize($storecfg, $volid, $size, $running); return if !$running;