http://bugzilla.novell.com/show_bug.cgi?id=618804 http://bugzilla.novell.com/show_bug.cgi?id=618804#c0 Summary: Wrong data returned on read after write if file size was changed with ftruncate Classification: openSUSE Product: openSUSE 11.3 Version: Factory Platform: Other OS/Version: openSUSE 11.3 Status: NEW Severity: Critical Priority: P5 - None Component: Kernel AssignedTo: kernel-maintainers@forge.provo.novell.com ReportedBy: richard.coe@med.ge.com QAContact: qa@suse.de Found By: --- Blocker: --- User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100317 SUSE/3.5.9-0.1.1 Firefox/3.5.9 GTB7.0 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 -- Configure bugmail: http://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.