Am 02.02.21 um 16:51 schrieb Eric Blake: > On 1/28/21 8:07 AM, Peter Lieven wrote: >> Signed-off-by: Peter Lieven <p...@kamp.de> > Your commit message says 'what', but not 'why'. Generally, the one-line > 'what' works well as the subject line, but you want the commit body to > give an argument why your patch should be applied, rather than blank. > > Here's the last time we tried to improve qemu-img dd: > https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg02618.html
I was not aware of that story. My use case is that I want to be able to "patch" an image that Qemu is able to handle by overwriting certain sectors. And I especially do not want to "mount" that image via qemu-nbd because I might not trust it. I totally want to avoid that the host system tries to analyse that image in terms of scanning the bootsector, partprobe, lvm etc. pp. > > where I also proposed adding seek=, and fixing skip= with count=. Your > patch does not do the latter. But the bigger complaint back then was > that 'qemu-img copy' should be able to do everything, and that qemu-img > dd should then just be a thin shim around 'qemu-img copy', rather than > having two parallel projects that diverge in their implementations. understood. I was not aware of an issue with skip and count. The patch works for me and I wanted to share it. But when I read the thread it seems that it would be a difficult task to get it merged. > > Your patch does not have the typical '---' divider and diffstat between > the commit message and the patch proper; this may be a factor of which > git packages you have installed, but having the diffstat present makes > it easier to see at a glance what your patch touches without reading the > entire email. I had to go hunting to learn if you added iotest coverage > of this new feature... > > ...and the answer was no, you didn't. You'll need to add that in v2 > (see the link to my earlier attempt at modifying dd for an example). I did not. Maybe I accidently killed the '---' divider. If I will make a V2 I will add an I/O test. Thanks for your suggestions, Peter
