** Also affects: qemu-kvm (Ubuntu Precise) Importance: Undecided Status: New
** Also affects: qemu-kvm (Ubuntu Quantal) Importance: Undecided Status: New ** Changed in: qemu-kvm (Ubuntu Precise) Importance: Undecided => High ** Changed in: qemu-kvm (Ubuntu Quantal) Importance: Undecided => High ** Changed in: qemu-kvm (Ubuntu Quantal) Status: New => Triaged ** Changed in: qemu-kvm (Ubuntu Precise) Status: New => Triaged ** Description changed: Something about qemu-nbd -r -c /dev/nbd0 someimg leaves cruft behind - subsequent connections get marked readonly. This is on quantal, haven't checked precise or raring. To demonstrate: # use one image qemu-img create -f qcow2 /tmp/1.qcow2 100M sudo qemu-nbd -c /dev/nbd2 /tmp/1.qcow2 sudo mkfs -t ext4 /dev/nbd2 sudo qemu-nbd -d /dev/nbd2 # use a second one on the same nbd device, shows that reuse works: qemu-img create -f qcow2 /tmp/2.qcow2 100M sudo qemu-nbd -c /dev/nbd2 /tmp/2.qcow2 sudo mkfs -t ext4 /dev/nbd2 sudo qemu-nbd -d /dev/nbd2 # connect an image in read only mode sudo qemu-nbd -r -c /dev/nbd2 /tmp/2.qcow2 sudo dumpe2fs /dev/nbd2 | head -n 3 sudo qemu-nbd -d /dev/nbd2 # now try to reuse in read-write mode again: qemu-img create -f qcow2 /tmp/3.qcow2 100M sudo qemu-nbd -c /dev/nbd2 /tmp/3.qcow2 sudo mkfs -t ext4 /dev/nbd2 # here it goes boom: mke2fs 1.42.5 (29-Jul-2012) /dev/nbd2: Operation not permitted while setting up superblock # still need to cleanup sudo qemu-nbd -d /dev/nbd2 + + =============================== + SRU Justification: + 1. Impact: mounting an nbd device as read-write after doing so read-only + will cause the mount to erroneously (and quietly) be read-only. + 2. Development fix: have qemu-nbd set the device to read-write when asked, + rather than only setting read-only. + 3. Stable fix: same as development fix + 4. Test case: See above + 5. Regression potential: The patch is localized to the handling of read-only + flag in qemu-nbd, so any regression should not affect anything else. + =============================== -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to qemu-kvm in Ubuntu. https://bugs.launchpad.net/bugs/1077838 Title: qemu-nbd -r -c taints device for subsequent usage, even after -d To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1077838/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs