Am 11.04.2012 12:05, schrieb Liu Yuan: > On 04/11/2012 03:49 PM, Kevin Wolf wrote: > >> I don't agree with this patch. If the documentation says that qemu-img >> always uses writeback, then the documentation must be fixed. >> >> We really don't care about flushes during an image conversion. It should >> just go as fast as it can. If any error happens in the middle, you'll >> have to throw the image away anyway, because it contains only half of >> what you need. So not having flushed doesn't really make any difference. >> >> As soon as a guest begins using the image with data that we really care >> about, it's probably running in a VM with non-unsafe mode, and then it >> gets flushed. > > > But we can set cache mode for qemu-img convert. So at least if we set > explicitly with other modes(for e.g, writeback) that ask to flush the > dirty bits, I think we should call brdv_flush(). > > If you agree, I'll update the patch with this modification.
Yes, adding the flush is fine, I just wouldn't change the default cache mode. Kevin
