On a virtual disk with a high number of sectors, the number of sectors was in some cases handled incorrectly, and converting a QEMU image failed with an "invalid argument" error. This update fixes the incorrect calculation that caused this error, and the described failure no longer occurs.
DescriptionStefan Hajnoczi
2015-02-26 14:32:47 UTC
Description of problem:
bdrv_make_zero() clamps the nb_sectors value:
if (nb_sectors > INT_MAX) {
nb_sectors = INT_MAX;
}
But INT_MAX is too large because bdrv_rw_co() performs the following check later:
if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
return -EINVAL;
}
Fam Zheng already fixed this bug upstream so we just need to backport the fix:
http://git.qemu-project.org/?p=qemu.git;a=commitdiff;h=f3a9cfddaec127078ac1898de6b063db8ac3bb48
How reproducible:
Deterministic
Steps to Reproduce:
1. qemu-img create input.img 2G
2. qemu-img create output.img 2G
3. sudo losetup -f output.img
4. qemu-img convert -t none -O raw input.img /dev/loop0
Actual results:
qemu-img: error writing zeroes at sector 0: Invalid argument
Expected results:
Success from qemu-img convert.
This same issue effects Fedora 21 as well and is displayed when trying to use OpenStack Cinder to convert Glance images. Could we backport the fix into Fedora 21 as well (it is preventing upstream CI from using Fedora ATM).
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://rhn.redhat.com/errata/RHBA-2015-2546.html
Description of problem: bdrv_make_zero() clamps the nb_sectors value: if (nb_sectors > INT_MAX) { nb_sectors = INT_MAX; } But INT_MAX is too large because bdrv_rw_co() performs the following check later: if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) { return -EINVAL; } Fam Zheng already fixed this bug upstream so we just need to backport the fix: http://git.qemu-project.org/?p=qemu.git;a=commitdiff;h=f3a9cfddaec127078ac1898de6b063db8ac3bb48 How reproducible: Deterministic Steps to Reproduce: 1. qemu-img create input.img 2G 2. qemu-img create output.img 2G 3. sudo losetup -f output.img 4. qemu-img convert -t none -O raw input.img /dev/loop0 Actual results: qemu-img: error writing zeroes at sector 0: Invalid argument Expected results: Success from qemu-img convert.