On 12/04/2015 07:44 AM, Denis V. Lunev wrote: > The patch adds Error ** parameter to load_vmstate call and fills error > inside. The caller after that properly reports error either through > monitor or via local stderr facility during VM start. > > This helper will be useful too for qmp_loadvm implementation. > > Signed-off-by: Denis V. Lunev <d...@openvz.org> > CC: Juan Quintela <quint...@redhat.com> > CC: Amit Shah <amit.s...@redhat.com> > CC: Markus Armbruster <arm...@redhat.com> > CC: Eric Blake <ebl...@redhat.com> > --- > include/sysemu/sysemu.h | 2 +- > migration/savevm.c | 28 ++++++++++++++++------------ > monitor.c | 6 +++++- > vl.c | 4 +++- > 4 files changed, 25 insertions(+), 15 deletions(-) >
> -int load_vmstate(const char *name)
> +int load_vmstate(const char *name, Error **errp)
> {
> BlockDriverState *bs, *bs_vm_state;
> QEMUSnapshotInfo sn;
> @@ -2035,20 +2035,22 @@ int load_vmstate(const char *name)
> AioContext *aio_context;
>
> if (!bdrv_all_can_snapshot(&bs)) {
> - error_report("Device '%s' is writable but does not support
> snapshots.",
> - bdrv_get_device_name(bs));
> + error_setg(errp,
> + "Device '%s' is writable but does not support snapshots.",
No trailing '.'
> @@ -2058,10 +2060,11 @@ int load_vmstate(const char *name)
> ret = bdrv_snapshot_find(bs_vm_state, &sn, name);
> aio_context_release(aio_context);
> if (ret < 0) {
> + error_setg_errno(errp, ret, "Snapshot '%s' not found", name);
You need '-ret', since error_setg_errno() expects positive errno values.
[maybe, for convenience, we should teach error_setg_errno() to handle
both -EINVAL and EINVAL identically - but it would need good
justification and would touch a lot of the tree, so if we do it, it
would be a separate series]
> return ret;
> } else if (sn.vm_state_size == 0) {
> - error_report("This is a disk-only snapshot. Revert to it offline "
> - "using qemu-img.");
> + error_setg(errp, "This is a disk-only snapshot. Revert to it offline
> "
> + "using qemu-img.");
According to Markus' recent cleanups, error_setg() should be a single
phrase, not two sentences. You'll want the second sentence to be added
with error_append_hint():
https://lists.gnu.org/archive/html/qemu-devel/2015-12/msg03508.html
> return -EINVAL;
> }
>
> @@ -2070,15 +2073,16 @@ int load_vmstate(const char *name)
>
> ret = bdrv_all_goto_snapshot(name, &bs);
> if (ret < 0) {
> - error_report("Error %d while activating snapshot '%s' on '%s'",
> - ret, name, bdrv_get_device_name(bs));
> + error_setg_errno(errp, ret,
-ret again
> + "Error while activating snapshot '%s' on '%s'",
> + name, bdrv_get_device_name(bs));
but thanks for getting rid of the weird 'error -5 while...' in the
message :)
> @@ -2092,7 +2096,7 @@ int load_vmstate(const char *name)
>
> migration_incoming_state_destroy();
> if (ret < 0) {
> - error_report("Error %d while loading VM state", ret);
> + error_setg_errno(errp, ret, "Error while loading VM state");
-ret again
> +++ b/monitor.c
> @@ -1739,10 +1739,14 @@ static void hmp_loadvm(Monitor *mon, const QDict
> *qdict)
> {
> int saved_vm_running = runstate_is_running();
> const char *name = qdict_get_str(qdict, "name");
> + Error *local_err = NULL;
>
> vm_stop(RUN_STATE_RESTORE_VM);
>
> - if (load_vmstate(name) == 0 && saved_vm_running) {
> + if (load_vmstate(name, &local_err) < 0) {
> + error_report_err(local_err);
> + }
> + if (saved_vm_running) {
> vm_start();
Logic bug. You blindly fall through, and could end up attempting
vm_start() even after an error, where previously it was not possible.
You probably meant '} else if (saved_vm_running) {'.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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