Am 31.08.2021 um 16:17 hat Guillaume Roche geschrieben: > QEMU exits in error when passing a vfat shared folder in read-only mode. > > To fix this issue, this patch removes any potential write permission > from cumulative_perms, when a read-only block device is in use. > > Buglink: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=918950 > > Signed-off-by: Guillaume Roche <gro...@genymobile.com> > --- > This is an attempt to fix this behavior, but it feels a bit hacky to me > since this patch checks for the vvfat format in a generic function. > > However, I'd be glad to have some advice to make it better. Anyway, I > ran the block tests to ensure this does not introduce any regression. > > To add some context: I know that this can be worked around by setting > the shared folder in rw mode. But our use-case requires using both > shared and VM snapshots, and QEMU prevents using snapshot with a rw > shared folder.
I don't think the behaviour is actually a bug: ide-hd requires a writable backend, so attaching a read-only vvfat node is a real error. You can either specify -drive read-only=on and use a device that can accept read-only backends (such as virtio-blk or ide-cd), or add a temporary writable qcow2 overlay with -snapshot or -drive snapshot=on so that the ide-hd device actually does get the writable backend it needs. Kevin
