Control: reassign -1 src:linux 4.6.1-1 Control: severity -1 important Control: tag -1 confirmed upstream
On Mon, 2016-07-04 at 00:47 -0400, westlake wrote: > Package: linux-image-4.6.0-0.bpo.1-amd64 > Version: 4.6.1-1~bpo8+1 > Severity: normal > > kernels 4.5 and 4.6 breaks qemu-nbd from mapping partitions > > qemu-nbd can map partitions from VM images and raw disk images to > /dev/nbdNpM nodes, but proper module options have to be loaded prior so > that qemu-nbd performs these additional mappings (the general consensus > around mapping image files has users issuing "kpartx -a /dev/", > but kpartx is not needed at all after issuing qemu-nbd) > > nothing is specially set up other than a module option file and that's > pretty much it -- there's just 2 or 3 commands for the testing --- all > which indicates the issue is more towards kernel than it is with qemu-nbd. I can confirm this issue. > after a modprobe nbd is issued, there is no "/dev/nbd0p1"-like devices, That much is correct behaviour since no device is attached yet... > so the main problem with kernels 4.5/4.6 is that qemu-nbd is not being > allowed to generate any device nodes. ("partition" device nodes that is > -- "/dev/nbd0" and "/dev/nbd1" nodes are generated by modprobe nbd) [...] ...but the kernel should scan the partition table for an nbd as soon as it is attached to a server. Currently that isn't happening. As a workaround, running 'fdisk' and then re-writing the same partition table triggers a rescan. This is almost certainly caused by: commit 37091fdd831f28a6509008542174ed324dd645bc Author: Markus Pargmann <m...@pengutronix.de> Date: Mon Jul 27 07:36:49 2015 +0200 nbd: Create size change events for userspace I have a rough idea of how to fix it and will update you later. Ben. -- Ben Hutchings Lowery's Law: If it jams, force it. If it breaks, it needed replacing anyway.
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