[libvirt] [PATCH] start: allow discarding managed save
Daniel Veillard
veillard at redhat.com
Tue Aug 30 10:47:41 UTC 2011
On Sat, Aug 27, 2011 at 05:21:11PM -0600, Eric Blake wrote:
> There have been several instances of people having problems with
> a broken managed save file causing 'virsh start' to fail, and not
> being aware that they could use 'virsh managedsave-remove dom' to
> fix things. Making it possible to do this as part of starting a
> domain makes the same functionality easier to find, and one less
> API call.
>
> * include/libvirt/libvirt.h.in (VIR_DOMAIN_START_FORCE_BOOT): New
> flag.
> * src/libvirt.c (virDomainCreateWithFlags): Document it.
> * src/qemu/qemu_driver.c (qemuDomainObjStart): Alter signature.
> (qemuAutostartDomain, qemuDomainStartWithFlags): Update callers.
> * tools/virsh.c (cmdStart): Expose it in virsh.
> * tools/virsh.pod (start): Document it.
> ---
> include/libvirt/libvirt.h.in | 1 +
> src/libvirt.c | 3 ++
> src/qemu/qemu_driver.c | 50 +++++++++++++++++++++++++----------------
> tools/virsh.c | 7 +++++-
> tools/virsh.pod | 5 ++-
> 5 files changed, 43 insertions(+), 23 deletions(-)
>
> diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
> index 53a2f7d..c51a5b9 100644
> --- a/include/libvirt/libvirt.h.in
> +++ b/include/libvirt/libvirt.h.in
> @@ -236,6 +236,7 @@ typedef enum {
> VIR_DOMAIN_START_PAUSED = 1 << 0, /* Launch guest in paused state */
> VIR_DOMAIN_START_AUTODESTROY = 1 << 1, /* Automatically kill guest when virConnectPtr is closed */
> VIR_DOMAIN_START_BYPASS_CACHE = 1 << 2, /* Avoid file system cache pollution */
> + VIR_DOMAIN_START_FORCE_BOOT = 1 << 3, /* Boot, discarding any managed save */
> } virDomainCreateFlags;
>
>
> diff --git a/src/libvirt.c b/src/libvirt.c
> index 65a099b..80c8b7c 100644
> --- a/src/libvirt.c
> +++ b/src/libvirt.c
> @@ -7081,6 +7081,9 @@ error:
> * the file, or fail if it cannot do so for the given system; this can allow
> * less pressure on file system cache, but also risks slowing loads from NFS.
> *
> + * If the VIR_DOMAIN_START_FORCE_BOOT flag is set, then any managed save
> + * file for this domain is discarded, and the domain boots from scratch.
> + *
> * Returns 0 in case of success, -1 in case of error
> */
> int
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index f21122d..5033998 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -120,9 +120,7 @@ static int qemudShutdown(void);
> static int qemuDomainObjStart(virConnectPtr conn,
> struct qemud_driver *driver,
> virDomainObjPtr vm,
> - bool start_paused,
> - bool autodestroy,
> - bool bypass_cache);
> + unsigned int flags);
>
> static int qemudDomainGetMaxVcpus(virDomainPtr dom);
>
> @@ -135,11 +133,16 @@ struct qemuAutostartData {
> };
>
> static void
> -qemuAutostartDomain(void *payload, const void *name ATTRIBUTE_UNUSED, void *opaque)
> +qemuAutostartDomain(void *payload, const void *name ATTRIBUTE_UNUSED,
> + void *opaque)
> {
> virDomainObjPtr vm = payload;
> struct qemuAutostartData *data = opaque;
> virErrorPtr err;
> + int flags = 0;
> +
> + if (data->driver->autoStartBypassCache)
> + flags |= VIR_DOMAIN_START_BYPASS_CACHE;
>
> virDomainObjLock(vm);
> virResetLastError();
> @@ -152,9 +155,7 @@ qemuAutostartDomain(void *payload, const void *name ATTRIBUTE_UNUSED, void *opaq
> } else {
> if (vm->autostart &&
> !virDomainObjIsActive(vm) &&
> - qemuDomainObjStart(data->conn, data->driver, vm,
> - false, false,
> - data->driver->autoStartBypassCache) < 0) {
> + qemuDomainObjStart(data->conn, data->driver, vm, flags) < 0) {
> err = virGetLastError();
> VIR_ERROR(_("Failed to autostart VM '%s': %s"),
> vm->def->name,
> @@ -4441,12 +4442,14 @@ static int
> qemuDomainObjStart(virConnectPtr conn,
> struct qemud_driver *driver,
> virDomainObjPtr vm,
> - bool start_paused,
> - bool autodestroy,
> - bool bypass_cache)
> + unsigned int flags)
> {
> int ret = -1;
> char *managed_save;
> + bool start_paused = (flags & VIR_DOMAIN_START_PAUSED) != 0;
> + bool autodestroy = (flags & VIR_DOMAIN_START_AUTODESTROY) != 0;
> + bool bypass_cache = (flags & VIR_DOMAIN_START_BYPASS_CACHE) != 0;
> + bool force_boot = (flags & VIR_DOMAIN_START_FORCE_BOOT) != 0;
>
> /*
> * If there is a managed saved state restore it instead of starting
> @@ -4458,13 +4461,22 @@ qemuDomainObjStart(virConnectPtr conn,
> goto cleanup;
>
> if (virFileExists(managed_save)) {
> - ret = qemuDomainObjRestore(conn, driver, vm, managed_save,
> - bypass_cache);
> + if (force_boot) {
> + if (unlink(managed_save) < 0) {
> + virReportSystemError(errno,
> + _("cannot remove managed save file %s"),
> + managed_save);
> + goto cleanup;
> + }
> + } else {
> + ret = qemuDomainObjRestore(conn, driver, vm, managed_save,
> + bypass_cache);
>
> - if ((ret == 0) && (unlink(managed_save) < 0))
> - VIR_WARN("Failed to remove the managed state %s", managed_save);
> + if ((ret == 0) && (unlink(managed_save) < 0))
> + VIR_WARN("Failed to remove the managed state %s", managed_save);
>
> - goto cleanup;
> + goto cleanup;
> + }
> }
>
> ret = qemuProcessStart(conn, driver, vm, NULL, start_paused,
> @@ -4493,7 +4505,8 @@ qemuDomainStartWithFlags(virDomainPtr dom, unsigned int flags)
>
> virCheckFlags(VIR_DOMAIN_START_PAUSED |
> VIR_DOMAIN_START_AUTODESTROY |
> - VIR_DOMAIN_START_BYPASS_CACHE, -1);
> + VIR_DOMAIN_START_BYPASS_CACHE |
> + VIR_DOMAIN_START_FORCE_BOOT, -1);
>
> qemuDriverLock(driver);
> vm = virDomainFindByUUID(&driver->domains, dom->uuid);
> @@ -4515,10 +4528,7 @@ qemuDomainStartWithFlags(virDomainPtr dom, unsigned int flags)
> goto endjob;
> }
>
> - if (qemuDomainObjStart(dom->conn, driver, vm,
> - (flags & VIR_DOMAIN_START_PAUSED) != 0,
> - (flags & VIR_DOMAIN_START_AUTODESTROY) != 0,
> - (flags & VIR_DOMAIN_START_BYPASS_CACHE) != 0) < 0)
> + if (qemuDomainObjStart(dom->conn, driver, vm, flags) < 0)
> goto endjob;
>
> ret = 0;
> diff --git a/tools/virsh.c b/tools/virsh.c
> index 15b9bdd..49034ae 100644
> --- a/tools/virsh.c
> +++ b/tools/virsh.c
> @@ -1537,9 +1537,12 @@ static const vshCmdOptDef opts_start[] = {
> {"console", VSH_OT_BOOL, 0, N_("attach to console after creation")},
> #endif
> {"paused", VSH_OT_BOOL, 0, N_("leave the guest paused after creation")},
> - {"autodestroy", VSH_OT_BOOL, 0, N_("automatically destroy the guest when virsh disconnects")},
> + {"autodestroy", VSH_OT_BOOL, 0,
> + N_("automatically destroy the guest when virsh disconnects")},
> {"bypass-cache", VSH_OT_BOOL, 0,
> N_("avoid file system cache when loading")},
> + {"force-boot", VSH_OT_BOOL, 0,
> + N_("force fresh boot by discarding any managed save")},
> {NULL, 0, 0, NULL}
> };
>
> @@ -1572,6 +1575,8 @@ cmdStart(vshControl *ctl, const vshCmd *cmd)
> flags |= VIR_DOMAIN_START_AUTODESTROY;
> if (vshCommandOptBool(cmd, "bypass-cache"))
> flags |= VIR_DOMAIN_START_BYPASS_CACHE;
> + if (vshCommandOptBool(cmd, "force-boot"))
> + flags |= VIR_DOMAIN_START_FORCE_BOOT;
>
> /* Prefer older API unless we have to pass a flag. */
> if ((flags ? virDomainCreateWithFlags(dom, flags)
> diff --git a/tools/virsh.pod b/tools/virsh.pod
> index 81d7a1e..2cd0f73 100644
> --- a/tools/virsh.pod
> +++ b/tools/virsh.pod
> @@ -890,7 +890,7 @@ The exact behavior of a domain when it shuts down is set by the
> I<on_shutdown> parameter in the domain's XML definition.
>
> =item B<start> I<domain-name> [I<--console>] [I<--paused>] [I<--autodestroy>]
> -[I<--bypass-cache>]
> +[I<--bypass-cache>] [I<--force-boot>]
>
> Start a (previously defined) inactive domain, either from the last
> B<managedsave> state, or via a fresh boot if no managedsave state is
> @@ -901,7 +901,8 @@ If I<--autodestroy> is requested, then the guest will be automatically
> destroyed when virsh closes its connection to libvirt, or otherwise
> exits. If I<--bypass-cache> is specified, and managedsave state exists,
> the restore will avoid the file system cache, although this may slow
> -down the operation.
> +down the operation. If I<--force-boot> is specified, then any
> +managedsave state is discarded and a fresh boot occurs.
>
> =item B<suspend> I<domain-id>
ACK,
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel at veillard.com | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
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