On Thu, Mar 28, 2024 at 04:39:04PM -0400, Stefan Hajnoczi wrote: > Run the tests with: > > $ make TARGETS=block_seek_hole -C tools/selftests run_tests > > Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx> > --- > tools/testing/selftests/Makefile | 1 + > .../selftests/block_seek_hole/Makefile | 17 +++ > .../testing/selftests/block_seek_hole/config | 1 + > .../selftests/block_seek_hole/map_holes.py | 37 +++++++ > .../testing/selftests/block_seek_hole/test.py | 103 ++++++++++++++++++ > 5 files changed, 159 insertions(+) > create mode 100644 tools/testing/selftests/block_seek_hole/Makefile > create mode 100644 tools/testing/selftests/block_seek_hole/config > create mode 100755 tools/testing/selftests/block_seek_hole/map_holes.py > create mode 100755 tools/testing/selftests/block_seek_hole/test.py > > +++ b/tools/testing/selftests/block_seek_hole/test.py > + > +# Different data layouts to test > + > +def data_at_beginning_and_end(f): > + f.write(b'A' * 4 * KB) > + f.seek(256 * MB) > + > + f.write(b'B' * 64 * KB) > + > + f.seek(1024 * MB - KB) > + f.write(b'C' * KB) > + > +def holes_at_beginning_and_end(f): > + f.seek(128 * MB) > + f.write(b'A' * 4 * KB) > + > + f.seek(512 * MB) > + f.write(b'B' * 64 * KB) > + > + f.truncate(1024 * MB) > + > +def no_holes(f): > + # Just 1 MB so test file generation is quick > + mb = b'A' * MB > + f.write(mb) > + > +def empty_file(f): > + f.truncate(1024 * MB) Is it also worth attempting to test a (necessarily sparse!) file larger than 2GiB to prove that we are 64-bit clean, even on a 32-bit system where lseek is different than lseek64? (I honestly have no idea if python always uses 64-bit seek even on 32-bit systems, although I would be surprised if it were not) -- Eric Blake, Principal Software Engineer Red Hat, Inc. Virtualization: qemu.org | libguestfs.org