On Sat, Sep 24, 2011 at 06:30:02PM -0600, Eric Blake wrote:
> Although a client can already obtain a snapshot's parent by
> dumping and parsing the xml, then doing a snapshot lookup by
> name, it is more efficient to get the parent in one step, which
> in turn will make operations that must traverse a snapshot
> hierarchy easier to perform.
>
> * include/libvirt/libvirt.h.in (virDomainSnapshotGetParent):
> Declare.
> * src/libvirt.c (virDomainSnapshotGetParent): New function.
> * src/libvirt_public.syms: Export it.
> * src/driver.h (virDrvDomainSnapshotGetParent): New callback.
> ---
> include/libvirt/libvirt.h.in | 4 +++
> src/driver.h | 5 ++++
> src/libvirt.c | 44 ++++++++++++++++++++++++++++++++++++++++++
> src/libvirt_public.syms | 5 ++++
> 4 files changed, 58 insertions(+), 0 deletions(-)
>
> diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
> index 39155a6..afeb83f 100644
> --- a/include/libvirt/libvirt.h.in
> +++ b/include/libvirt/libvirt.h.in
> @@ -2711,6 +2711,10 @@ int virDomainHasCurrentSnapshot(virDomainPtr domain, unsigned int flags);
> virDomainSnapshotPtr virDomainSnapshotCurrent(virDomainPtr domain,
> unsigned int flags);
>
> +/* Get a handle to the parent snapshot, if one exists */
> +virDomainSnapshotPtr virDomainSnapshotGetParent(virDomainSnapshotPtr snapshot,
> + unsigned int flags);
> +
> typedef enum {
> VIR_DOMAIN_SNAPSHOT_REVERT_RUNNING = 1 << 0, /* Run after revert */
> VIR_DOMAIN_SNAPSHOT_REVERT_PAUSED = 1 << 1, /* Pause after revert */
> diff --git a/src/driver.h b/src/driver.h
> index 3792003..7dcab8f 100644
> --- a/src/driver.h
> +++ b/src/driver.h
> @@ -590,6 +590,10 @@ typedef int
> (*virDrvDomainHasCurrentSnapshot)(virDomainPtr domain, unsigned int flags);
>
> typedef virDomainSnapshotPtr
> + (*virDrvDomainSnapshotGetParent)(virDomainSnapshotPtr snapshot,
> + unsigned int flags);
> +
> +typedef virDomainSnapshotPtr
> (*virDrvDomainSnapshotCurrent)(virDomainPtr domain,
> unsigned int flags);
>
> @@ -854,6 +858,7 @@ struct _virDriver {
> virDrvDomainSnapshotListNames domainSnapshotListNames;
> virDrvDomainSnapshotLookupByName domainSnapshotLookupByName;
> virDrvDomainHasCurrentSnapshot domainHasCurrentSnapshot;
> + virDrvDomainSnapshotGetParent domainSnapshotGetParent;
> virDrvDomainSnapshotCurrent domainSnapshotCurrent;
> virDrvDomainRevertToSnapshot domainRevertToSnapshot;
> virDrvDomainSnapshotDelete domainSnapshotDelete;
> diff --git a/src/libvirt.c b/src/libvirt.c
> index 8f94b11..38fcfbc 100644
> --- a/src/libvirt.c
> +++ b/src/libvirt.c
> @@ -16150,6 +16150,50 @@ error:
> }
>
> /**
> + * virDomainSnapshotGetParent:
> + * @snapshot: a snapshot object
> + * @flags: unused flag parameters; callers should pass 0
> + *
> + * Get the parent snapshot for @snapshot, if any.
> + *
> + * Returns a domain snapshot object or NULL in case of failure. If the
> + * given snapshot is a root (no parent), then the VIR_ERR_NO_DOMAIN_SNAPSHOT
> + * error is raised.
> + */
> +virDomainSnapshotPtr
> +virDomainSnapshotGetParent(virDomainSnapshotPtr snapshot,
> + unsigned int flags)
> +{
> + virConnectPtr conn;
> +
> + VIR_DEBUG("snapshot=%p, flags=%x", snapshot, flags);
> +
> + virResetLastError();
> +
> + if (!VIR_IS_DOMAIN_SNAPSHOT(snapshot)) {
> + virLibDomainSnapshotError(VIR_ERR_INVALID_DOMAIN_SNAPSHOT,
> + __FUNCTION__);
> + virDispatchError(NULL);
> + return NULL;
> + }
> +
> + conn = snapshot->domain->conn;
> +
> + if (conn->driver->domainSnapshotGetParent) {
> + virDomainSnapshotPtr snap;
> + snap = conn->driver->domainSnapshotGetParent(snapshot, flags);
> + if (!snap)
> + goto error;
> + return snap;
> + }
> +
> + virLibConnError(VIR_ERR_NO_SUPPORT, __FUNCTION__);
> +error:
> + virDispatchError(conn);
> + return NULL;
> +}
> +
> +/**
> * virDomainRevertToSnapshot:
> * @snapshot: a domain snapshot object
> * @flags: bitwise-OR of virDomainSnapshotRevertFlags
> diff --git a/src/libvirt_public.syms b/src/libvirt_public.syms
> index 8a6d55a..cef14f0 100644
> --- a/src/libvirt_public.syms
> +++ b/src/libvirt_public.syms
> @@ -489,4 +489,9 @@ LIBVIRT_0.9.5 {
> virDomainSnapshotGetName;
> } LIBVIRT_0.9.4;
>
> +LIBVIRT_0.9.7 {
> + global:
> + virDomainSnapshotGetParent;
> +} LIBVIRT_0.9.5;
> +
> # .... define new API here using predicted next version number ....
> --
> 1.7.4.4
ACK, interface and intent looks fine !
I have seen another patch today touching the libvirt_public.syms
though, tweaking may be needed by someone :-)
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel@xxxxxxxxxxxx | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
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