On Fri, Feb 27, 2015 at 02:54:39PM -0500, Max Reitz wrote: > When allocating a new cluster, the first write to it must be the one > doing the allocation, because that one pads its write request to the > cluster size; if another write to that cluster is executed before it, > that write will be overwritten due to the padding. > > See https://bugs.launchpad.net/qemu/+bug/1422307 for what can go wrong > without this patch. > > Cc: qemu-stable <qemu-sta...@nongnu.org> > Signed-off-by: Max Reitz <mre...@redhat.com> > --- > v3: Hopefully finally found the real issue which causes the problems > described in the bug report; at least it sounds very reasonable and > I can no longer reproduce any of the issues described there. > Thank you, Paolo and Stefan! > --- > block/vdi.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+)
I think this is overkill but let's merge it since the patch has been written. A simple s->lock for I/O operations would have been fine since this block driver was never designed for parallel I/O. Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
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