Public bug reported: If you try to convert a blank image to qcow2 that is less than 100kiB in size then qemu-img hangs trying to seek to the end of the file.
$ truncate --size 102399 /tmp/temp $ qemu-img convert -p -O qcow2 /tmp/temp /tmp/temp2.qcow2 I'm finding this on all versions of qemu-img v2. strace shows a seek loop. ioctl(6, FS_IOC_FIEMAP, 0xb5e68dc4) = 0 _llseek(6, 0, [100000], SEEK_END) = 0 ioctl(6, FS_IOC_FIEMAP, 0xb5e68dc4) = 0 _llseek(6, 0, [100000], SEEK_END) = 0 ioctl(6, FS_IOC_FIEMAP, 0xb5e68dc4) = 0 _llseek(6, 0, [100000], SEEK_END) = 0 ioctl(6, FS_IOC_FIEMAP, 0xb5e68dc4) = 0 _llseek(6, 0, [100000], SEEK_END) = 0 ioctl(6, FS_IOC_FIEMAP, 0xb5e68dc4) = 0 _llseek(6, 0, [100000], SEEK_END) = 0 ioctl(6, FS_IOC_FIEMAP, 0xb5e68dc4) = 0 _llseek(6, 0, [100000], SEEK_END) = 0 ioctl(6, FS_IOC_FIEMAP, 0xb5e68dc4) = 0 _llseek(6, 0, [100000], SEEK_END) = 0 ioctl(6, FS_IOC_FIEMAP, 0xb5e68dc4) = 0 _llseek(6, 0, [100000], SEEK_END) = 0 ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: qemu-utils 2.0.0+dfsg-2ubuntu1.10 ProcVersionSignature: User Name 3.13.0-43.72-generic 3.13.11.11 Uname: Linux 3.13.0-43-generic i686 ApportVersion: 2.14.1-0ubuntu3.6 Architecture: i386 Date: Tue Jan 13 14:30:39 2015 SourcePackage: qemu UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: qemu (Ubuntu) Importance: Undecided Status: Confirmed ** Tags: apport-bug i386 trusty uec-images -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to qemu in Ubuntu. https://bugs.launchpad.net/bugs/1410288 Title: qemu-img conversion to qcow2 hangs with blank image less than 100kiB To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1410288/+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