Re: [libvirt] [PATCH 05/16] snapshot: Drop virDomainSnapshotDef.current
On 3/20/19 2:57 PM, John Ferlan wrote:
On 3/20/19 1:40 AM, Eric Blake wrote:
> The only use for the 'current' member of virDomainSnapshotDef was with
> the PARSE/FORMAT_INTERNAL flag for controlling an internal-use
> <active> element marking whether a particular snapshot definition was
> current, and even then, only by the qemu driver on output, and by qemu
> and test driver on input. But this duplicates vm->snapshot_current,
> and gets in the way of potential simplifications to have qemu store a
> single file for all snapshots rather than one file per snapshot. Get
> rid of the member by adding a bool* parameter during parse (ignored if
> the PARSE_INTERNAL flag is not set), and by adding a new flag during
> format (if FORMAT_INTERNAL is set, the value printed in <active>
> depends on the new FORMAT_CURRENT). Then update the qemu driver
> accordingly.
>
> Signed-off-by: Eric Blake <eblake(a)redhat.com>
> ---
> + * caps are ignored. If flags does not include
> + * VIR_DOMAIN_SNAPSHOT_PARSE_INTERNAL, then current is ignored.
> */
> static virDomainSnapshotDefPtr
> virDomainSnapshotDefParse(xmlXPathContextPtr ctxt,
> virCapsPtr caps,
> virDomainXMLOptionPtr xmlopt,
> + bool *current,
> unsigned int flags)
> {
> virDomainSnapshotDefPtr def = NULL;
> @@ -350,7 +352,7 @@ virDomainSnapshotDefParse(xmlXPathContextPtr ctxt,
> _("Could not find 'active' element"));
> goto cleanup;
> }
> - def->current = active != 0;
> + *current = active != 0;
Even though we've restricted usage via @flags where PARSE_INTERNAL is
set, should this be prefaced by:
if (current)
guess I'm concerned with some future cut-copy-paste error...
Good call. I'm squashing this in:
diff --git i/src/conf/snapshot_conf.c w/src/conf/snapshot_conf.c
index bf5fdc0647..65094766f0 100644
--- i/src/conf/snapshot_conf.c
+++ w/src/conf/snapshot_conf.c
@@ -347,6 +347,11 @@ virDomainSnapshotDefParse(xmlXPathContextPtr ctxt,
}
if (flags & VIR_DOMAIN_SNAPSHOT_PARSE_INTERNAL) {
+ if (!current) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("internal parse requested with NULL
current"));
+ goto cleanup;
+ }
if (virXPathInt("string(./active)", ctxt, &active) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Could not find 'active' element"));
> }
>
> if (!offline && virSaveCookieParse(ctxt, &def->cookie,
saveCookie) < 0)
Reviewed-by: John Ferlan <jferlan(a)redhat.com>
John
The setting of ->current_snapshot in/around calls to
qemuDomainSnapshotWriteMetadata was particularly "interesting" to
follow, but looks fine.
Yeah, and the next few patches clear it up by getting rid of
current_snapshot altogether :) (well, moving it into ObjList).
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
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