Comment 34 for bug 1292234

Revision history for this message
Chris J Arges (arges) wrote : Re: qcow2 image corruption in trusty (qemu 1.7 and 2.0 candidate)

Serge,
So I was able to just compile my own qemu and test with that.

I did attempt a reverse bisect, and was able to reproduce as early as v1.1 and also reproduce on master HEAD.
v1.0 was inconclusive because qcow2 format I made with the newer binary seemed to be incompatible with v1.0; however from Jamies testing this seems to be a working version; so I'd say somewhere between v1.0.0, v1.1.0 lies the original change that enabled this issue. As I've been unable to reproduce this without virsh, reverse bisecting and using older qemu versions is a bit challenging as machine types change, features virsh wants to use aren't available, etc.

Another interesting thing I tested today was I was able to reproduce with ext4 with extents disabled; maybe that gives more clues. Just to make sure I wasn't crazy, mkfs'd the partition to vanilla ext4 and iterated for most of the afternoon with no failures.

My next steps are going to be enabling verbose output for qcow2, looking more deeply into what gets corrupted in the file, and turning on host filesystem debugging.

--chris