Hi list,
following command fails since 5.1 (tested on kernel 5.4.60):
# qemu-img convert -p -f raw -O raw /dev/zvol/pool/disk-1 /dev/vg/disk-1
qemu-img: error while writing at byte 2157968896: Device or resource busy
(source is ZFS here, but doesn't matter in practice, it always fails the
same; offset changes slightly but consistently hovers around 2^31)
strace shows the following:
fallocate(13, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 2157968896,
4608) = -1 EBUSY (Device or resource busy)
Other fallocate calls leading up to this work fine.
This happens since commit edafc70c0c "qemu-img convert: Don't pre-zero
images", before that all fallocates happened at the start. Reverting the
commit and calling qemu-img exactly the same way on the same data works
fine. Simply retrying the syscall on EBUSY (like EINTR) does *not* work,
once it fails it keeps failing with the same error.
I couldn't find anything related to EBUSY on fallocate, and it only
happens on LVM targets... Any idea or pointers where to look?
~ Stefan
