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snapshot: Make virDomainSnapshotObjList use MomentObjList

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Now that the generic moment code does pretty much everything that both
snapshots and checkpoints will need, it's time to replace the
now-duplicate code in virdomainsnapshotobjlist.c with simpler calls
into the generic code. I considered using sub-classing (a
'virDomainMomentObjList parent;' member, but that requires making the
opaque type visible in headers; so for now, I stuck with a container
instead (a 'virDomainMomentObjListPtr base;' member).

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
This commit is contained in:
Eric Blake 2019-03-22 00:46:57 -05:00
parent dc8d3dc6cd
commit ac0379043a
2 changed files with 33 additions and 240 deletions
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268
src/conf/virdomainsnapshotobjlist.c
View File

@ -35,12 +35,7 @@
VIR_LOG_INIT("conf.virdomainsnapshotobjlist");
struct _virDomainSnapshotObjList {
/* name string -> virDomainMomentObj mapping
* for O(1), lockless lookup-by-name */
virHashTable *objs;
virDomainMomentObj metaroot; /* Special parent of all root snapshots */
virDomainMomentObjPtr current; /* The current snapshot, if any */
virDomainMomentObjListPtr base;
};
@ -74,7 +69,7 @@ virDomainSnapshotObjListParse(const char *xmlStr,
_("incorrect flags for bulk parse"));
return -1;
}
if (virDomainSnapshotObjListSize(snapshots) != 0) {
if (virDomainMomentObjListSize(snapshots->base) != 0) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
_("bulk define of snapshots only possible with "
"no existing snapshot"));
@ -140,7 +135,7 @@ virDomainSnapshotObjListParse(const char *xmlStr,
if (ret < 0) {
/* There were no snapshots before this call; so on error, just
* blindly delete anything created before the failure. */
virDomainSnapshotObjListRemoveAll(snapshots);
virDomainMomentObjListRemoveAll(snapshots->base);
}
xmlXPathFreeContext(ctxt);
xmlFreeDoc(xml);
@ -210,55 +205,14 @@ virDomainSnapshotObjListFormat(virBufferPtr buf,
}
/* Snapshot Obj functions */
static virDomainMomentObjPtr virDomainMomentObjNew(void)
virDomainMomentObjPtr
virDomainSnapshotAssignDef(virDomainSnapshotObjListPtr snapshots,
virDomainSnapshotDefPtr def)
{
virDomainMomentObjPtr snapshot;
if (VIR_ALLOC(snapshot) < 0)
return NULL;
VIR_DEBUG("obj=%p", snapshot);
return snapshot;
return virDomainMomentAssignDef(snapshots->base, &def->common);
}
static void virDomainMomentObjFree(virDomainMomentObjPtr snapshot)
{
if (!snapshot)
return;
VIR_DEBUG("obj=%p", snapshot);
virDomainSnapshotDefFree(virDomainSnapshotObjGetDef(snapshot));
VIR_FREE(snapshot);
}
virDomainMomentObjPtr virDomainSnapshotAssignDef(virDomainSnapshotObjListPtr snapshots,
virDomainSnapshotDefPtr def)
{
virDomainMomentObjPtr snap;
if (virHashLookup(snapshots->objs, def->common.name) != NULL) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("unexpected domain snapshot %s already exists"),
def->common.name);
return NULL;
}
if (!(snap = virDomainMomentObjNew()))
return NULL;
if (virHashAddEntry(snapshots->objs, snap->def->name, snap) < 0) {
VIR_FREE(snap);
return NULL;
}
snap->def = &def->common;
return snap;
}
/* Snapshot Obj List functions */
static bool
virDomainSnapshotFilter(virDomainMomentObjPtr obj,
unsigned int flags)
@ -291,76 +245,32 @@ virDomainSnapshotFilter(virDomainMomentObjPtr obj,
}
static void
virDomainSnapshotObjListDataFree(void *payload,
const void *name ATTRIBUTE_UNUSED)
{
virDomainMomentObjPtr obj = payload;
virDomainMomentObjFree(obj);
}
virDomainSnapshotObjListPtr
virDomainSnapshotObjListNew(void)
{
virDomainSnapshotObjListPtr snapshots;
if (VIR_ALLOC(snapshots) < 0)
return NULL;
snapshots->objs = virHashCreate(50, virDomainSnapshotObjListDataFree);
if (!snapshots->objs) {
snapshots->base = virDomainMomentObjListNew();
if (!snapshots->base) {
VIR_FREE(snapshots);
return NULL;
}
return snapshots;
}
void
virDomainSnapshotObjListFree(virDomainSnapshotObjListPtr snapshots)
{
if (!snapshots)
return;
virHashFree(snapshots->objs);
virDomainMomentObjListFree(snapshots->base);
VIR_FREE(snapshots);
}
struct virDomainMomentNameData {
char **const names;
int maxnames;
unsigned int flags;
int count;
bool error;
virDomainMomentObjListFilter filter;
};
static int virDomainMomentObjListCopyNames(void *payload,
const void *name ATTRIBUTE_UNUSED,
void *opaque)
{
virDomainMomentObjPtr obj = payload;
struct virDomainMomentNameData *data = opaque;
if (data->error)
return 0;
/* Caller already sanitized flags. Filtering on DESCENDANTS was
* done by choice of iteration in the caller. */
if ((data->flags & VIR_DOMAIN_SNAPSHOT_LIST_LEAVES) && obj->nchildren)
return 0;
if ((data->flags & VIR_DOMAIN_SNAPSHOT_LIST_NO_LEAVES) && !obj->nchildren)
return 0;
if (data->filter(obj, data->flags))
return 0;
if (data->names && data->count < data->maxnames &&
VIR_STRDUP(data->names[data->count], obj->def->name) < 0) {
data->error = true;
return 0;
}
data->count++;
return 0;
}
int
virDomainSnapshotObjListGetNames(virDomainSnapshotObjListPtr snapshots,
virDomainMomentObjPtr from,
@ -368,75 +278,23 @@ virDomainSnapshotObjListGetNames(virDomainSnapshotObjListPtr snapshots,
int maxnames,
unsigned int flags)
{
struct virDomainMomentNameData data = { names, maxnames, flags, 0,
false, virDomainSnapshotFilter };
size_t i;
if (!from) {
/* LIST_ROOTS and LIST_DESCENDANTS have the same bit value,
* but opposite semantics. Toggle here to get the correct
* traversal on the metaroot. */
flags ^= VIR_DOMAIN_SNAPSHOT_LIST_ROOTS;
from = &snapshots->metaroot;
}
/* We handle LIST_ROOT/LIST_DESCENDANTS and LIST_TOPOLOGICAL directly,
* mask those bits out to determine when we must use the filter callback. */
data.flags &= ~(VIR_DOMAIN_SNAPSHOT_LIST_DESCENDANTS |
VIR_DOMAIN_SNAPSHOT_LIST_TOPOLOGICAL);
/* If this common code is being used, we assume that all snapshots
* have metadata, and thus can handle METADATA up front as an
* all-or-none filter. XXX This might not always be true, if we
* add the ability to track qcow2 internal snapshots without the
* use of metadata. */
if ((data.flags & VIR_DOMAIN_SNAPSHOT_FILTERS_METADATA) ==
VIR_DOMAIN_SNAPSHOT_LIST_NO_METADATA)
return 0;
data.flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_METADATA;
/* For ease of coding the visitor, it is easier to zero each group
* where all of the bits are set. */
if ((data.flags & VIR_DOMAIN_SNAPSHOT_FILTERS_LEAVES) ==
if ((flags & VIR_DOMAIN_SNAPSHOT_FILTERS_LEAVES) ==
VIR_DOMAIN_SNAPSHOT_FILTERS_LEAVES)
data.flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_LEAVES;
if ((data.flags & VIR_DOMAIN_SNAPSHOT_FILTERS_STATUS) ==
flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_LEAVES;
if ((flags & VIR_DOMAIN_SNAPSHOT_FILTERS_STATUS) ==
VIR_DOMAIN_SNAPSHOT_FILTERS_STATUS)
data.flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_STATUS;
if ((data.flags & VIR_DOMAIN_SNAPSHOT_FILTERS_LOCATION) ==
flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_STATUS;
if ((flags & VIR_DOMAIN_SNAPSHOT_FILTERS_LOCATION) ==
VIR_DOMAIN_SNAPSHOT_FILTERS_LOCATION)
data.flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_LOCATION;
if (flags & VIR_DOMAIN_SNAPSHOT_LIST_DESCENDANTS) {
/* We could just always do a topological visit; but it is
* possible to optimize for less stack usage and time when a
* simpler full hashtable visit or counter will do. */
if (from->def || (names &&
(flags & VIR_DOMAIN_SNAPSHOT_LIST_TOPOLOGICAL)))
virDomainMomentForEachDescendant(from,
virDomainMomentObjListCopyNames,
&data);
else if (names || data.flags)
virHashForEach(snapshots->objs, virDomainMomentObjListCopyNames,
&data);
else
data.count = virHashSize(snapshots->objs);
} else if (names || data.flags) {
virDomainMomentForEachChild(from,
virDomainMomentObjListCopyNames, &data);
} else {
data.count = from->nchildren;
}
if (data.error) {
for (i = 0; i < data.count; i++)
VIR_FREE(names[i]);
return -1;
}
return data.count;
flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_LOCATION;
return virDomainMomentObjListGetNames(snapshots->base, from, names,
maxnames, flags,
virDomainSnapshotFilter);
}
int
virDomainSnapshotObjListNum(virDomainSnapshotObjListPtr snapshots,
virDomainMomentObjPtr from,
@ -445,19 +303,12 @@ virDomainSnapshotObjListNum(virDomainSnapshotObjListPtr snapshots,
return virDomainSnapshotObjListGetNames(snapshots, from, NULL, 0, flags);
}
virDomainMomentObjPtr
virDomainSnapshotFindByName(virDomainSnapshotObjListPtr snapshots,
const char *name)
{
return name ? virHashLookup(snapshots->objs, name) : &snapshots->metaroot;
}
/* Return the number of objects currently in the list */
int
virDomainSnapshotObjListSize(virDomainSnapshotObjListPtr snapshots)
{
return virHashSize(snapshots->objs);
return virDomainMomentFindByName(snapshots->base, name);
}
@ -465,7 +316,7 @@ virDomainSnapshotObjListSize(virDomainSnapshotObjListPtr snapshots)
virDomainMomentObjPtr
virDomainSnapshotGetCurrent(virDomainSnapshotObjListPtr snapshots)
{
return snapshots->current;
return virDomainMomentGetCurrent(snapshots->base);
}
@ -473,9 +324,7 @@ virDomainSnapshotGetCurrent(virDomainSnapshotObjListPtr snapshots)
const char *
virDomainSnapshotGetCurrentName(virDomainSnapshotObjListPtr snapshots)
{
if (snapshots->current)
return snapshots->current->def->name;
return NULL;
return virDomainMomentGetCurrentName(snapshots->base);
}
@ -484,7 +333,7 @@ bool
virDomainSnapshotIsCurrentName(virDomainSnapshotObjListPtr snapshots,
const char *name)
{
return snapshots->current && STREQ(snapshots->current->def->name, name);
return virDomainMomentIsCurrentName(snapshots->base, name);
}
@ -493,7 +342,7 @@ void
virDomainSnapshotSetCurrent(virDomainSnapshotObjListPtr snapshots,
virDomainMomentObjPtr snapshot)
{
snapshots->current = snapshot;
virDomainMomentSetCurrent(snapshots->base, snapshot);
}
@ -502,19 +351,15 @@ bool
virDomainSnapshotObjListRemove(virDomainSnapshotObjListPtr snapshots,
virDomainMomentObjPtr snapshot)
{
bool ret = snapshots->current == snapshot;
virHashRemoveEntry(snapshots->objs, snapshot->def->name);
if (ret)
snapshots->current = NULL;
return ret;
return virDomainMomentObjListRemove(snapshots->base, snapshot);
}
/* Remove all snapshots tracked in the list */
void
virDomainSnapshotObjListRemoveAll(virDomainSnapshotObjListPtr snapshots)
{
virHashRemoveAll(snapshots->objs);
virDomainMomentDropChildren(&snapshots->metaroot);
return virDomainMomentObjListRemoveAll(snapshots->base);
}
@ -523,51 +368,10 @@ virDomainSnapshotForEach(virDomainSnapshotObjListPtr snapshots,
virHashIterator iter,
void *data)
{
return virHashForEach(snapshots->objs, iter, data);
return virDomainMomentForEach(snapshots->base, iter, data);
}
/* Struct and callback function used as a hash table callback; each call
* inspects the pre-existing snapshot->def->parent field, and adjusts
* the snapshot->parent field as well as the parent's child fields to
* wire up the hierarchical relations for the given snapshot. The error
* indicator gets set if a parent is missing or a requested parent would
* cause a circular parent chain. */
struct moment_set_relation {
virDomainSnapshotObjListPtr snapshots;
int err;
};
static int
virDomainMomentSetRelations(void *payload,
const void *name ATTRIBUTE_UNUSED,
void *data)
{
virDomainMomentObjPtr obj = payload;
struct moment_set_relation *curr = data;
virDomainMomentObjPtr tmp;
virDomainMomentObjPtr parent;
parent = virDomainSnapshotFindByName(curr->snapshots, obj->def->parent);
if (!parent) {
curr->err = -1;
parent = &curr->snapshots->metaroot;
VIR_WARN("snapshot %s lacks parent", obj->def->name);
} else {
tmp = parent;
while (tmp && tmp->def) {
if (tmp == obj) {
curr->err = -1;
parent = &curr->snapshots->metaroot;
VIR_WARN("snapshot %s in circular chain", obj->def->name);
break;
}
tmp = tmp->parent;
}
}
virDomainMomentSetParent(obj, parent);
return 0;
}
/* Populate parent link and child count of all snapshots, with all
* assigned defs having relations starting as 0/NULL. Return 0 on
* success, -1 if a parent is missing or if a circular relationship
@ -575,13 +379,7 @@ virDomainMomentSetRelations(void *payload,
int
virDomainSnapshotUpdateRelations(virDomainSnapshotObjListPtr snapshots)
{
struct moment_set_relation act = { snapshots, 0 };
virDomainMomentDropChildren(&snapshots->metaroot);
virHashForEach(snapshots->objs, virDomainMomentSetRelations, &act);
if (act.err)
snapshots->current = NULL;
return act.err;
return virDomainMomentUpdateRelations(snapshots->base);
}

5
src/conf/virdomainsnapshotobjlist.h
View File

@ -27,10 +27,6 @@
# include "virdomainmomentobjlist.h"
# include "virbuffer.h"
/* Filter that returns true if a given moment matches the filter flags */
typedef bool (*virDomainMomentObjListFilter)(virDomainMomentObjPtr obj,
unsigned int flags);
virDomainSnapshotObjListPtr virDomainSnapshotObjListNew(void);
void virDomainSnapshotObjListFree(virDomainSnapshotObjListPtr snapshots);
@ -59,7 +55,6 @@ int virDomainSnapshotObjListNum(virDomainSnapshotObjListPtr snapshots,
unsigned int flags);
virDomainMomentObjPtr virDomainSnapshotFindByName(virDomainSnapshotObjListPtr snapshots,
const char *name);
int virDomainSnapshotObjListSize(virDomainSnapshotObjListPtr snapshots);
virDomainMomentObjPtr virDomainSnapshotGetCurrent(virDomainSnapshotObjListPtr snapshots);
const char *virDomainSnapshotGetCurrentName(virDomainSnapshotObjListPtr snapshots);
bool virDomainSnapshotIsCurrentName(virDomainSnapshotObjListPtr snapshots,