From: Eric Blake <eblake@redhat.com>
To: "Denis V. Lunev" <den@openvz.org>
Cc: Amit Shah <amit.shah@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
qemu-devel@nongnu.org, quintela@redhat.com
Subject: Re: [Qemu-devel] [PATCH 4/5] migration: improve error reporting for load_vmstate
Date: Wed, 23 Dec 2015 14:56:27 -0700 [thread overview]
Message-ID: <567B188B.40108@redhat.com> (raw)
In-Reply-To: <1449240275-26196-5-git-send-email-den@openvz.org>
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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 <den@openvz.org>
> CC: Juan Quintela <quintela@redhat.com>
> CC: Amit Shah <amit.shah@redhat.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Eric Blake <eblake@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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next prev parent reply other threads:[~2015-12-23 21:56 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-04 14:44 [Qemu-devel] [PATCH v2 for 2.6 0/5] QMP wrappers for VM snapshot operations Denis V. Lunev
2015-12-04 14:44 ` [Qemu-devel] [PATCH 1/5] migration: split hmp_savevm to do_savevm and hmp_savevm wrapper Denis V. Lunev
2015-12-23 21:27 ` Eric Blake
2016-01-08 11:27 ` Denis V. Lunev
2016-01-08 16:14 ` Eric Blake
2016-01-08 16:40 ` Denis V. Lunev
2016-01-08 17:54 ` Eric Blake
2016-01-08 17:59 ` Denis V. Lunev
2015-12-04 14:44 ` [Qemu-devel] [PATCH 2/5] qmp: create qmp_savevm command Denis V. Lunev
2015-12-23 21:40 ` Eric Blake
2015-12-23 21:45 ` Denis V. Lunev
2016-01-08 13:19 ` Denis V. Lunev
2015-12-04 14:44 ` [Qemu-devel] [PATCH 3/5] qmp: create qmp_delvm command Denis V. Lunev
2015-12-23 21:48 ` Eric Blake
2015-12-04 14:44 ` [Qemu-devel] [PATCH 4/5] migration: improve error reporting for load_vmstate Denis V. Lunev
2015-12-23 21:56 ` Eric Blake [this message]
2015-12-04 14:44 ` [Qemu-devel] [PATCH 5/5] qmp: create QMP implementation of loadvm command Denis V. Lunev
2015-12-23 23:15 ` Eric Blake
2015-12-11 9:33 ` [Qemu-devel] [PATCH v2 for 2.6 0/5] QMP wrappers for VM snapshot operations Denis V. Lunev
2015-12-18 6:10 ` Denis V. Lunev
2015-12-23 21:10 ` Denis V. Lunev
-- strict thread matches above, loose matches on Subject: below --
2016-01-08 14:00 [Qemu-devel] [PATCH v3 " Denis V. Lunev
2016-01-08 14:00 ` [Qemu-devel] [PATCH 4/5] migration: improve error reporting for load_vmstate Denis V. Lunev
2016-01-08 14:10 [Qemu-devel] [PATCH v4 0/5] QMP wrappers for VM snapshot operations Denis V. Lunev
2016-01-08 14:10 ` [Qemu-devel] [PATCH 4/5] migration: improve error reporting for load_vmstate Denis V. Lunev
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