On 25.09.19 23:28, Eric Blake wrote: > On 9/25/19 1:32 PM, Max Reitz wrote: >> And by that I mean all XFS versions, as far as I can tell. All details >> are in the comment below. >> >> We never noticed this problem because we only read the first number from >> qemu-img info's "disk size" output -- and that is effectively useless, >> because qemu-img prints a human-readable value (which generally includes >> a decimal point). That will be fixed in the next patch. >> >> Signed-off-by: Max Reitz <mre...@redhat.com> >> --- >> tests/qemu-iotests/125 | 40 ++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 40 insertions(+) >> >> diff --git a/tests/qemu-iotests/125 b/tests/qemu-iotests/125 >> index df328a63a6..0ef51f1e21 100755 >> --- a/tests/qemu-iotests/125 >> +++ b/tests/qemu-iotests/125 >> @@ -49,6 +49,46 @@ if [ -z "$TEST_IMG_FILE" ]; then >> TEST_IMG_FILE=$TEST_IMG >> fi >> +# Test whether we are running on a broken XFS version. There is this >> +# bug: >> + >> +# $ rm -f foo >> +# $ touch foo >> +# $ block_size=4096 # Your FS's block size >> +# $ fallocate -o $((block_size / 2)) -l $block_size foo >> +# $ LANG=C xfs_bmap foo | grep hole >> +# 1: [8..15]: hole >> +# >> +# The problem is that the XFS driver rounds down the offset and >> +# rounds up the length to the block size, but independently. > > Eww. I concur you uncovered a bug. Have you reported this to xfs folks?
I have now. Took a bit of kernel compiling to see whether what I think would fix it works. Max
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