from: https://bugzilla.kernel.org/show_bug.cgi?id=16165 [^] > we use the direct async I/O API for file I/O in VirtualBox since 3.2 and got > some reports about corrupted guest filesystems. It turned out that only users > are affected which disk images are stored on a ext4 filesystem. I could create > a testcase which reproduces the error. Further investigation showed that the > data corruption happens if ftruncate is used, data is written to the so far > unallocated offset and immediately read back. The buffer holding the read data > contains only \0 afterwards. The data is there if the file is closed and > another program is used to view the file content (less for example). > Everything works if ftruncate is not used. The test case is in the original bug report, which includes patches for ext4 and xfs. Reproducible: Always Additional Information This bug is preventing the usage of ext4 and xfs based filesystems with any software which uses aio and ftruncate. VirtualBox is is rendered unuseable with ext4 and XFS filesystems as a result of this bug.
Still not fixed in 2.6.35
The ext4 patch is here: http://git.kernel.org/?p=linux/kernel/git/tytso/ext4.git;a=commitdiff_plain;h=5b3ff237bef43b9e7fb7d1eb858e29b73fd664f9 The direct-io and xfs patches were merged today, after 2.6.35: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff_plain;h=40e2e97316af6e62affab7a392e792494b8d9dde http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff_plain;h=fb511f2150174b18b28ad54708c1adda0df39b17
Should be fixed in 2.6.34.2-33.fc13
Patches also went in 2.6.35-3.fc14
kernel-2.6.34.2-34.fc13 has been submitted as an update for Fedora 13. http://admin.fedoraproject.org/updates/kernel-2.6.34.2-34.fc13
kernel-2.6.34.2-34.fc13 has been pushed to the Fedora 13 testing repository. If problems still persist, please make note of it in this bug report. If you want to test the update, you can install it with su -c 'yum --enablerepo=updates-testing update kernel'. You can provide feedback for this update here: http://admin.fedoraproject.org/updates/kernel-2.6.34.2-34.fc13
kernel-2.6.34.3-37.fc13 has been submitted as an update for Fedora 13. http://admin.fedoraproject.org/updates/kernel-2.6.34.3-37.fc13
kernel-2.6.34.3-37.fc13 has been pushed to the Fedora 13 testing repository. If problems still persist, please make note of it in this bug report. If you want to test the update, you can install it with su -c 'yum --enablerepo=updates-testing update kernel'. You can provide feedback for this update here: http://admin.fedoraproject.org/updates/kernel-2.6.34.3-37.fc13
2.6.34 update kernel has been removed.
kernel-2.6.34.6-47.fc13 has been submitted as an update for Fedora 13. https://admin.fedoraproject.org/updates/kernel-2.6.34.6-47.fc13
kernel-2.6.34.6-47.fc13 has been pushed to the Fedora 13 stable repository. If problems still persist, please make note of it in this bug report.