Hi Lennart, Thanks for the report, I'll look into it. FWIW, we've been using LOOP_CONFIGURE on Android with lo_offset/lo_sizelimit without issues, but it may be a particular configuration that's causing issues. Thanks, Martijn On Mon, Aug 24, 2020 at 5:44 PM Lennart Poettering <mzxreary@xxxxxxxxxxx> wrote: > > Hi! > > Even with fe6a8fc5ed2f0081f17375ae2005718522c392c6 the LOOP_CONFIGURE > ioctl doesn't work correctly. It gets confused if the > lo_offset/lo_sizelimit fields are set to non-zero. > > In a quick test I ran (on Linux 5.8.3) I call LOOP_CONFIGURE with > .lo_offset=3221204992 and .lo_sizelimit=50331648 and immediately > verify the size of the block device with BLKGETSIZE64. It should of > course return 50331648, but actually returns 3271557120. (the precise > values have no particular relevance, it's just what I happened to use > in my test.) If I instead use LOOP_SET_STATUS64 with the exact same > parameters, everything works correctly. In either case, if I use > LOOP_GET_STATUS64 insted of BLKGETSIZE64 to verify things, everything > looks great. > > My guess is that the new ioctl simply doesn't properly propagate the > size limit into the underlying block device like it should. I didn't > have the time to investigate further though. > > Lennart
