On Fri, May 3, 2019, 23:21 Eric Blake <[email protected]> wrote: > On 5/2/19 11:37 PM, Thomas Huth wrote: > > On 02/05/2019 23.56, Eric Blake wrote: > >> On 4/28/19 10:18 AM, Thomas Huth wrote: > >>> QEMU iotest 175 is failing for me when I run it with -raw: > >>> > >> > >>> == creating image with default preallocation == > >>> Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 > >>> -size=1048576, blocks=0 > >>> +size=1048576, blocks=2 > >> > >> What filesystem? > > > > ext4 > > > > Hmm, it's passing for me on ext4, but that probably means we have > different configuration parameters. I'm not sure how to easily show what > parameters a particular ext4 partition uses to compare the differences > between your setup and mine (mine is tuned to whatever defaults Fedora's > installer chose on my behalf), so maybe someone else can chime in. > > >> It should be fairly obvious that 'stat -c blocks=%b' is > >> file-system dependent (some allocate slightly more or less space, based > >> on granularities and on predictions of future use), so we may need to > >> update the test to apply a filter or otherwise allow a bit of fuzz in > >> the answer. But 0/2 is definitely different than... > >>> > >>> == creating image with preallocation off == > >>> Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 > preallocation=off > >>> -size=1048576, blocks=0 > >>> +size=1048576, blocks=2 > >>> > >>> == creating image with preallocation full == > >>> Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 > preallocation=full > >>> -size=1048576, blocks=2048 > >>> +size=1048576, blocks=2050 > >> > >> 2048/2050, so we DO have some indication of whether the file is sparse > >> or fully allocated. > > > > Maybe we could check that the value after "blocks=" is a single digit in > > the first case, and matches "blocks=20.." in the second case? > > I wonder if 'qemu-img map --output=json $TEST_IMG' might be any more > reliable (at least for ignoring any extra block allocations associated > with the file, if it is some journaling option or xattr or other reason > why your files seem to occupy more disk sectors than just the size of > the file would imply). >
I think it should work better and is more correct, testing actual sparsness instead of underlying file system implementation. I can send a fix next week. Nir > -- > Eric Blake, Principal Software Engineer > Red Hat, Inc. +1-919-301-3226 > Virtualization: qemu.org | libvirt.org > >
