From commit https://git.qemu.org/?p=qemu.git;a=commit;h=c8bb23cbdbe32f5c326365e0a82e1b0e68cdcd8a for qcow2 file in ocfs2 filesystem, do_fallocate with (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE) will be called when allocate a new cluster. It's not necessary and also cause data error.
1. create a ocfs2 cluster and `mkfs.ocfs2 -b 4k -C 1M -N 2 /dev/sdb1` then `mount /dev/sdb1 /mnt` 2. qemu-img create -f qcow2 -o cluster_size=256k /mnt/test.img 1G 3. attach /mnt/test.img to a linux vm as vdb 4. in vm, `dd if=/root/foo of=/dev/vdb bs=4k count=1` 5. `hexdump -C /dev/vdb -n 4096` the output is not identical to the file /root/foo After remove do_fallocate with (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE) in handle_aiocb_write_zeroes , it's good. Chang Limin
