Am 17.11.2017 um 18:07 hat Vladimir Sementsov-Ogievskiy geschrieben: > 17.11.2017 19:47, Eric Blake wrote: > > If an image contains persistent snapshots, we cannot use the > > bitmaps > > > fast path of bdrv_make_empty() to clear the image during > > qemu-img commit, because that will lose the clusters related > > to the bitmaps. > > > > Also leave a comment in qcow2_read_extensions to remind future > > feature additions to think about fast-path removal, since we > > just barely fixed the same bug for LUKS encryption. > > > > It's a pain that qemu-img has not yet been taught to manipulate, > > or even at a very minimum display, information about persistent > > bitmaps; instead, we have to use QMP commands. It's also a > > pain that only qeury-block and x-debug-block-dirty-bitmap-sha256 > > will allow bitmap introspection; but the former requires the > > node to be hooked to a block device, and the latter is experimental. > > sorry for that pain =(. > > Honestly, I don't understand why such a simple and obvious fix needs an > additional test.
Because we could otherwise accidentally break it again in the future. If there is a feature that you care about, make sure to have a test for everything in it, and that you add a regression test for every bug that you fix. Kevin