On Wed, Mar 05, 2014 at 02:53:10PM -0500, Tomoki Sekiyama wrote:
> Adds an quiesced flag into qemuDomainObjPrivate that tracks whether guest
> filesystems of the domain is quiesced of not.
> It also modify error code from qemuDomainSnapshotFSFreeze and
> qemuDomainSnapshotFSThaw, so that a caller can know whether the command is
> actually sent to the guest agent. If the error is caused before sending a
> freeze command, a counterpart thaw command shouldn't be sent to avoid
> confusing the tracking of quiesced status.
> ---
> src/qemu/qemu_domain.h | 2 ++
> src/qemu/qemu_driver.c | 41 +++++++++++++++++++++++++++++++----------
> 2 files changed, 33 insertions(+), 10 deletions(-)
>
> diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
> index 0bed50b..8a79a00 100644
> --- a/src/qemu/qemu_domain.h
> +++ b/src/qemu/qemu_domain.h
> @@ -176,6 +176,8 @@ struct _qemuDomainObjPrivate {
> char **qemuDevices; /* NULL-terminated list of devices aliases known to QEMU */
>
> bool hookRun; /* true if there was a hook run over this domain */
> +
> + bool quiesced; /* true if the domain filesystems are quiesced */
> };
>
> typedef enum {
You will also want to update qemuDomainObjPrivateXMLFormat and
qemuDomainObjPrivateXMLParse so that this new 'quiesced' attribute
is preserved in the live XML state across libvirtd restarts.
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 9aad2dc..8109e46 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -12040,6 +12040,8 @@ cleanup:
> }
>
>
> +/* Return -1 if request is not sent to agent due to misconfig, -2 on agent
> + * failure, and number of frozen filesystems on success. */
> static int
> qemuDomainSnapshotFSFreeze(virDomainObjPtr vm) {
> qemuDomainObjPrivatePtr priv = vm->privateData;
> @@ -12056,14 +12058,24 @@ qemuDomainSnapshotFSFreeze(virDomainObjPtr vm) {
> _("QEMU guest agent is not configured"));
> return -1;
> }
> + if (priv->quiesced) {
> + virReportError(VIR_ERR_OPERATION_INVALID, "%s",
> + _("domain is already quiesced"));
> + return -1;
> + }
>
> qemuDomainObjEnterAgent(vm);
> freezed = qemuAgentFSFreeze(priv->agent);
> qemuDomainObjExitAgent(vm);
>
> - return freezed;
> + if (freezed >= 0)
> + priv->quiesced = true;
> +
> + return freezed < 0 ? -2 : freezed;
> }
>
> +/* Return -1 if request is not sent to agent due to misconfig, -2 on agent
> + * failure, and number of thawed filesystems on success. */
> static int
> qemuDomainSnapshotFSThaw(virDomainObjPtr vm, bool report)
> {
> @@ -12084,6 +12096,11 @@ qemuDomainSnapshotFSThaw(virDomainObjPtr vm, bool report)
> _("QEMU guest agent is not configured"));
> return -1;
> }
> + if (!priv->quiesced && report) {
> + virReportError(VIR_ERR_OPERATION_INVALID, "%s",
> + _("domain is not quiesced"));
> + return -1;
> + }
>
> qemuDomainObjEnterAgent(vm);
> if (!report)
> @@ -12093,8 +12110,11 @@ qemuDomainSnapshotFSThaw(virDomainObjPtr vm, bool report)
> virSetError(err);
> qemuDomainObjExitAgent(vm);
>
> + if (thawed >= 0)
> + priv->quiesced = false;
> +
> virFreeError(err);
> - return thawed;
> + return thawed < 0 ? -2 : thawed;
> }
And in both these methods you want to call virDomainSaveStatus after changing
the priv->quiesced flag, to save the status XML to disk
>
> /* The domain is expected to be locked and inactive. */
> @@ -13069,17 +13089,18 @@ qemuDomainSnapshotCreateActiveExternal(virConnectPtr conn,
> goto cleanup;
>
> /* If quiesce was requested, then issue a freeze command, and a
> - * counterpart thaw command, no matter what. The command will
> - * fail if the guest is paused or the guest agent is not
> - * running. */
> + * counterpart thaw command when the it is actually sent to agent.
> + * The command will fail if the guest is paused or the guest agent is not
> + * running, or is already quiesced. */
> if (flags & VIR_DOMAIN_SNAPSHOT_CREATE_QUIESCE) {
> - if (qemuDomainSnapshotFSFreeze(vm) < 0) {
> - /* helper reported the error */
> - thaw = -1;
> + int freeze = qemuDomainSnapshotFSFreeze(vm);
> + if (freeze < 0) {
> + /* the helper reported the error */
> + if (freeze != -1)
> + thaw = -1; /* the command is sent but agent failed */
> goto endjob;
> - } else {
> - thaw = 1;
> }
> + thaw = 1;
> }
I'm not sure I understand why you're changing this ? Are you trying to
deal with the case where the guest is already frozen, but someone has
still supplied the VIR_DOMAIN_SNAPSHOT_CREATE_QUIESCE flag ?
I'd probably argue that such usage is a bug we should report to the
caller as an error.
Regards,
Daniel
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