Re: [libvirt] [PATCH] qemu: fix domjobabort regression

This reverts commit ef1065cf5ac; see also this bug report: https://bugzilla.redhat.com/show_bug.cgi?id=751900 In qemu 0.15.1 and earlier, during migration to file, the qemu_savevm_state_begin and qemu_savevm_state_iterate methods will both process as much migration data as possible until either 1. The file descriptor returns EAGAIN 2. The bandwidth rate limit is reached If we set the rate limit to ULONG_MAX, test 2 never becomes true. We're passing a plain file descriptor to QEMU and POSIX does not support EAGAIN on regular files / block devices, so test 1 never becomes true either. In the 'virsh save --bypass-cache' case, we pass a pipe instead of a regular fd, but using a pipe adds I/O overhead, so always passing a pipe just so qemu can see EAGAIN doesn't seem nice. The ultimate fix needs to come from qemu - background migration must