[libvirt] [PATCH] qemu: better error message when block job can't succeed

https://bugzilla.redhat.com/show_bug.cgi?id=1140981 reports that the qemu-kvm shipped as part of RHEL 7.0 intentionally cripples block jobs by removing the 'block-stream' QMP command, but that our probe for whether block jobs work was merely whether 'block-job-cancel' exists. Meanwhile, older qemu spelled the two commands block_stream and block_job_cancel. We know of no qemu build that has block-stream while lacking block-job-cancel, so it is easiest to change our witness to the command that starts a job rather than ends one. On RHEL, this results in changing the message from an ugly: error: Requested operation is not valid: Command 'block-stream' is not found to a nicer: error: unsupported configuration: block jobs not supported with this qemu binary * src/qemu/qemu_capabilities.h (QEMU_CAPS_BLOCKJOB_SYNC): Tweak comment. * src/qemu/qemu_capabilities.c (virQEMUCapsCommands): Look for stream rather than cancel when determining the flavor of block jobs supported. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- src/qemu/qemu_capabilities.c | 4 ++-- src/qemu/qemu_capabilities.h | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index 6fcb5c7..b6c0f1b 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -1422,8 +1422,8 @@ struct virQEMUCapsStringFlags { struct virQEMUCapsStringFlags virQEMUCapsCommands[] = { { "system_wakeup", QEMU_CAPS_WAKEUP }, { "transaction", QEMU_CAPS_TRANSACTION }, - { "block_job_cancel", QEMU_CAPS_BLOCKJOB_SYNC }, - { "block-job-cancel", QEMU_CAPS_BLOCKJOB_ASYNC }, + { "block_stream", QEMU_CAPS_BLOCKJOB_SYNC }, + { "block-stream", QEMU_CAPS_BLOCKJOB_ASYNC }, { "dump-guest-memory", QEMU_CAPS_DUMP_GUEST_MEMORY }, { "query-spice", QEMU_CAPS_SPICE }, { "query-kvm", QEMU_CAPS_KVM }, diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h index 0214f30..c0e2172 100644 --- a/src/qemu/qemu_capabilities.h +++ b/src/qemu/qemu_capabilities.h @@ -127,8 +127,8 @@ typedef enum { QEMU_CAPS_SCSI_DISK_CHANNEL = 87, /* Is scsi-disk.channel available? */ QEMU_CAPS_SCSI_BLOCK = 88, /* -device scsi-block */ QEMU_CAPS_TRANSACTION = 89, /* transaction monitor command */ - QEMU_CAPS_BLOCKJOB_SYNC = 90, /* RHEL 6.2 block_job_cancel */ - QEMU_CAPS_BLOCKJOB_ASYNC = 91, /* qemu 1.1 block-job-cancel */ + QEMU_CAPS_BLOCKJOB_SYNC = 90, /* old block_job_cancel, block_stream */ + QEMU_CAPS_BLOCKJOB_ASYNC = 91, /* new block-job-cancel, block-stream */ QEMU_CAPS_SCSI_CD = 92, /* -device scsi-cd */ QEMU_CAPS_IDE_CD = 93, /* -device ide-cd */ QEMU_CAPS_NO_USER_CONFIG = 94, /* -no-user-config */ -- 1.9.3