So, if I understand well, it's "just" some kind of race condition in the handling of writes in the VDI driver of Qemu?
Does that mean it can also affect VMs running with VDI disk(s)? -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1422307 Title: qemu-nbd corrupts files Status in QEMU: New Bug description: Dear all, On Trusty, in certain situations, try to copy files over a qemu-nbd mounted file system leads to write errors (and thus, file corruption). Here is the last example I tried: -> virtual disk is a VDI disk -> It has only one partition, in FAT Here is my mount process: # modprobe nbd max_part=63 # qemu-nbd -c /dev/nbd0 "virtual_disk.vdi" # partprobe /dev/nbd0 # mount /dev/nbd0p1 /tmp/mnt/ Partition is properly mounted at that point: /dev/nbd0p1 on /tmp/mnt type vfat (rw) Now, when I copy a file (rather big, ~28MB): # cp file_to_copy /tmp/mnt/ ; sync # md5sum /tmp/mnt/file_to_copy 2efc9f32e4267782b11d63d2f128a363 /tmp/mnt/file_to_copy # umount /tmp/mnt # mount /dev/nbd0p1 /tmp/mnt/ # md5sum /tmp/mnt/file_to_copy 42b0a3bf73f704d03ce301716d7654de /tmp/mnt/file_to_copy The first hash was obviously the right one. On a previous attempt I did, I spotted thanks to vbindiff that parts of the file were just filed with 0s instead of actual data. It will randomly work after several attempts to write. Version information: # qemu-nbd --version qemu-nbd version 0.0.1 Written by Anthony Liguori. Cheers, To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1422307/+subscriptions