Re: [libvirt] [PATCH] qemu: Refactor parsing of block device IO tuning parameters.

This patch refactors the JSON parsing function that extracts the block IO tuning parameters from qemu's output. The most impacting change concerns the error message that is returned if the reply from qemu does not contain the needed data. The data for IO parameter tuning were added in qemu 1.1 and the previous error message was confusing. This patch also breaks long lines and extracts a multiple time used code pattern to a macro. --- Old error message looks like: # virsh blkdeviotune asdf hda error: Unable to get block I/O throttle parameters error: internal error cannot read total_bytes_sec and the new: # virsh blkdeviotune asdf hda error: Unable to get block I/O throttle parameters error: internal error block_io_throttle field 'total_bytes_sec' missing in qemu's output