qemu live migration failed

qemu live migration failed

the dest qemu report this error.

Receiving block device images
Completed 0 %^Mqemu-system-x86_64: block/io.c:1348: bdrv_aligned_pwritev: Assertion `child->perm & BLK_PERM_WRITE' failed.

this bug is caused by this patch:
http://git.qemu-project.org/?p=qemu.git;a=commit;h=d35ff5e6b3aa3a706b0aa3bcf11400fac945b67a

rollback this commit, the problem solved.