On Tue, May 23, 2017 at 11:41:52AM -0400, Theodore Ts'o wrote: > On Tue, May 23, 2017 at 12:20:59AM +0100, Marc Thomas wrote: > > Hi All, > > > > Would you agree this is a bug? As I understand it, reading from an > > "unpopulated" region of a sparse file should return all zeros - so the > > md5sum should be the same before and after migration. > > I agree that sparse files should be properly handled after bmap2extent > conversion. This code hasn't received that much use or testing, but > I've tried to replicate the problem and I haven't succeeded. This > script works for me: > > ----- cut here ----- > #!/bin/bash > > rm -f /tmp/foo.img > mke2fs -t ext3 -Fq /tmp/foo.img 65536 > mount -o loop /tmp/foo.img /mnt > dd if=/etc/motd of=/mnt/test bs=4k >& /dev/null > dd if=/etc/motd of=/mnt/test conv=notrunc seek=32 bs=4k >& /dev/null > dd if=/etc/motd of=/mnt/test2 bs=4k >& /dev/null > dd if=/etc/motd of=/mnt/test2 conv=notrunc seek=1024 bs=4k >& /dev/null > lsattr /mnt/test* > md5sum /mnt/test* > /mnt/MD5SUMS > umount /mnt > e2fsck -fy -E bmap2extent /tmp/foo.img > mount -o loop /tmp/foo.img /mnt > md5sum -c /mnt/MD5SUMS > lsattr /mnt/test* > umount /mnt > ----- cut here ----- > > Maybe you can come up with a simple repro case that fails for you? Or take an e2image of one of the affected filesystems so that the developers can directly reproduce your error case. :) e2image -Q /dev/sda1 /some/qcow/dump/file (Preferably xz the dumpfile before uploading...) --D > > Thanks, > > - Ted >
