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qemu: backup: Rewrite backup bitmap handling to the new bitmap semantics

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Reuse qemuBlockGetBitmapMergeActions which allows removal of the ad-hoc
implementation of bitmap merging for backup. The new approach is simpler
and also more robust in case some of the bitmaps break as they remove
the dependency on the whole chain of bitmaps working.

The new approach also allows backups if a snapshot is created outside of
libvirt.

Additionally the code is greatly simplified.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Peter Krempa 2020-05-22 14:48:46 +02:00
parent 4fa8654ece
commit e0d8d989e2
4 changed files with 64 additions and 260 deletions
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222
src/qemu/qemu_backup.c
View File

@ -173,199 +173,58 @@ qemuBackupDiskDataCleanup(virDomainObjPtr vm,
}
/**
* qemuBackupBeginCollectIncrementalCheckpoints:
* @vm: domain object
* @incrFrom: name of checkpoint representing starting point of incremental backup
*
* Returns a NULL terminated list of pointers to checkpoint definitions in
* chronological order starting from the 'current' checkpoint until reaching
* @incrFrom.
*/
static virDomainMomentDefPtr *
qemuBackupBeginCollectIncrementalCheckpoints(virDomainObjPtr vm,
const char *incrFrom)
int
qemuBackupDiskPrepareOneBitmapsChain(virStorageSourcePtr backingChain,
virStorageSourcePtr targetsrc,
const char *targetbitmap,
const char *incremental,
virJSONValuePtr actions,
virHashTablePtr blockNamedNodeData)
{
virDomainMomentObjPtr n = virDomainCheckpointGetCurrent(vm->checkpoints);
g_autofree virDomainMomentDefPtr *incr = NULL;
size_t nincr = 0;
g_autoptr(virJSONValue) tmpactions = NULL;
while (n) {
virDomainMomentDefPtr def = n->def;
if (VIR_APPEND_ELEMENT_COPY(incr, nincr, def) < 0)
return NULL;
if (STREQ(def->name, incrFrom)) {
def = NULL;
if (VIR_APPEND_ELEMENT_COPY(incr, nincr, def) < 0)
return NULL;
return g_steal_pointer(&incr);
}
if (!n->def->parent_name)
break;
n = virDomainCheckpointFindByName(vm->checkpoints, n->def->parent_name);
}
virReportError(VIR_ERR_OPERATION_INVALID,
_("could not locate checkpoint '%s' for incremental backup"),
incrFrom);
return NULL;
}
static int
qemuBackupGetBitmapMergeRange(virStorageSourcePtr from,
const char *bitmapname,
virJSONValuePtr *actions,
virStorageSourcePtr *to,
const char *diskdst,
virHashTablePtr blockNamedNodeData)
{
g_autoptr(virJSONValue) act = virJSONValueNewArray();
virStorageSourcePtr tmpsrc = NULL;
virStorageSourcePtr n;
bool foundbitmap = false;
for (n = from; virStorageSourceIsBacking(n); n = n->backingStore) {
qemuBlockNamedNodeDataBitmapPtr bitmap = NULL;
if (!(bitmap = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData,
n,
bitmapname)))
break;
foundbitmap = true;
if (bitmap->inconsistent) {
virReportError(VIR_ERR_INVALID_ARG,
_("bitmap '%s' for image '%s%u' is inconsistent"),
bitmap->name, diskdst, n->id);
return -1;
}
if (qemuMonitorTransactionBitmapMergeSourceAddBitmap(act,
n->nodeformat,
bitmapname) < 0)
return -1;
tmpsrc = n;
}
if (!foundbitmap) {
virReportError(VIR_ERR_INVALID_ARG,
_("failed to find bitmap '%s' in image '%s%u'"),
bitmapname, diskdst, from->id);
if (qemuBlockGetBitmapMergeActions(backingChain, NULL, targetsrc,
incremental, targetbitmap, NULL,
&tmpactions,
blockNamedNodeData) < 0)
return -1;
}
*actions = g_steal_pointer(&act);
*to = tmpsrc;
if (tmpactions &&
virJSONValueArrayConcat(actions, tmpactions) < 0)
return -1;
return 0;
}
virJSONValuePtr
qemuBackupDiskPrepareOneBitmapsChain(virDomainMomentDefPtr *incremental,
virStorageSourcePtr backingChain,
virHashTablePtr blockNamedNodeData,
const char *diskdst)
{
g_autoptr(virJSONValue) ret = NULL;
size_t incridx = 0;
virStorageSourcePtr n = backingChain;
ret = virJSONValueNewArray();
for (incridx = 0; incremental[incridx]; incridx++) {
g_autoptr(virJSONValue) tmp = virJSONValueNewArray();
virStorageSourcePtr tmpsrc = NULL;
virDomainCheckpointDefPtr chkdef = (virDomainCheckpointDefPtr) incremental[incridx];
bool checkpoint_has_disk = false;
size_t i;
for (i = 0; i < chkdef->ndisks; i++) {
if (STRNEQ_NULLABLE(diskdst, chkdef->disks[i].name))
continue;
if (chkdef->disks[i].type == VIR_DOMAIN_CHECKPOINT_TYPE_BITMAP)
checkpoint_has_disk = true;
break;
}
if (!checkpoint_has_disk) {
if (!incremental[incridx + 1]) {
virReportError(VIR_ERR_INVALID_ARG,
_("disk '%s' not found in checkpoint '%s'"),
diskdst, incremental[incridx]->name);
return NULL;
}
continue;
}
if (qemuBackupGetBitmapMergeRange(n, incremental[incridx]->name,
&tmp, &tmpsrc, diskdst,
blockNamedNodeData) < 0)
return NULL;
if (virJSONValueArrayConcat(ret, tmp) < 0)
return NULL;
n = tmpsrc;
}
return g_steal_pointer(&ret);
}
static int
qemuBackupDiskPrepareOneBitmaps(struct qemuBackupDiskData *dd,
virJSONValuePtr actions,
virDomainMomentDefPtr *incremental,
virHashTablePtr blockNamedNodeData)
{
g_autoptr(virJSONValue) mergebitmaps = NULL;
g_autoptr(virJSONValue) mergebitmapsstore = NULL;
if (!qemuBlockBitmapChainIsValid(dd->domdisk->src,
dd->backupdisk->incremental,
blockNamedNodeData)) {
virReportError(VIR_ERR_INVALID_ARG,
_("missing or broken bitmap '%s' for disk '%s'"),
dd->backupdisk->incremental, dd->domdisk->dst);
return -1;
}
if (!(mergebitmaps = qemuBackupDiskPrepareOneBitmapsChain(incremental,
dd->domdisk->src,
blockNamedNodeData,
dd->domdisk->dst)))
if (qemuBackupDiskPrepareOneBitmapsChain(dd->domdisk->src,
dd->domdisk->src,
dd->incrementalBitmap,
dd->backupdisk->incremental,
actions,
blockNamedNodeData) < 0)
return -1;
if (!(mergebitmapsstore = virJSONValueCopy(mergebitmaps)))
return -1;
if (qemuMonitorTransactionBitmapAdd(actions,
dd->domdisk->src->nodeformat,
dd->incrementalBitmap,
false,
true, 0) < 0)
return -1;
if (qemuMonitorTransactionBitmapMerge(actions,
dd->domdisk->src->nodeformat,
dd->incrementalBitmap,
&mergebitmaps) < 0)
return -1;
if (qemuMonitorTransactionBitmapAdd(actions,
dd->store->nodeformat,
dd->incrementalBitmap,
false,
true, 0) < 0)
return -1;
if (qemuMonitorTransactionBitmapMerge(actions,
dd->store->nodeformat,
dd->incrementalBitmap,
&mergebitmapsstore) < 0)
if (qemuBackupDiskPrepareOneBitmapsChain(dd->domdisk->src,
dd->store,
dd->incrementalBitmap,
dd->backupdisk->incremental,
actions,
blockNamedNodeData) < 0)
return -1;
return 0;
@ -382,7 +241,6 @@ qemuBackupDiskPrepareDataOne(virDomainObjPtr vm,
virQEMUDriverConfigPtr cfg)
{
qemuDomainObjPrivatePtr priv = vm->privateData;
g_autofree virDomainMomentDefPtr *incremental = NULL;
/* set data structure */
dd->backupdisk = backupdisk;
@ -421,16 +279,12 @@ qemuBackupDiskPrepareDataOne(virDomainObjPtr vm,
return -1;
if (dd->backupdisk->incremental) {
if (!(incremental = qemuBackupBeginCollectIncrementalCheckpoints(vm, dd->backupdisk->incremental)))
return -1;
if (dd->backupdisk->exportbitmap)
dd->incrementalBitmap = g_strdup(dd->backupdisk->exportbitmap);
else
dd->incrementalBitmap = g_strdup_printf("backup-%s", dd->domdisk->dst);
if (qemuBackupDiskPrepareOneBitmaps(dd, actions, incremental,
blockNamedNodeData) < 0)
if (qemuBackupDiskPrepareOneBitmaps(dd, actions, blockNamedNodeData) < 0)
return -1;
}
@ -884,8 +738,8 @@ qemuBackupBegin(virDomainObjPtr vm,
if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, QEMU_ASYNC_JOB_BACKUP)))
goto endjob;
if ((ndd = qemuBackupDiskPrepareData(vm, def, blockNamedNodeData,
actions, cfg, &dd)) <= 0) {
if ((ndd = qemuBackupDiskPrepareData(vm, def, blockNamedNodeData, actions,
cfg, &dd)) <= 0) {
if (ndd == 0) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
_("no disks selected for backup"));

12
src/qemu/qemu_backup.h
View File

@ -53,8 +53,10 @@ qemuBackupGetJobInfoStats(virQEMUDriverPtr driver,
qemuDomainJobInfoPtr jobInfo);
/* exported for testing */
virJSONValuePtr
qemuBackupDiskPrepareOneBitmapsChain(virDomainMomentDefPtr *incremental,
virStorageSourcePtr backingChain,
virHashTablePtr blockNamedNodeData,
const char *diskdst);
int
qemuBackupDiskPrepareOneBitmapsChain(virStorageSourcePtr backingChain,
virStorageSourcePtr targetsrc,
const char *targetbitmap,
const char *incremental,
virJSONValuePtr actions,
virHashTablePtr blockNamedNodeData);

86
tests/qemublocktest.c
View File

@ -716,65 +716,6 @@ testQemuBitmapGetFakeChainEntry(virStorageSourcePtr src,
}
typedef virDomainMomentDefPtr testMomentList;
static void
testMomentListFree(testMomentList *list)
{
testMomentList *tmp = list;
if (!list)
return;
while (*tmp) {
virObjectUnref(*tmp);
tmp++;
}
g_free(list);
}
G_DEFINE_AUTOPTR_CLEANUP_FUNC(testMomentList, testMomentListFree);
static virDomainMomentDefPtr
testQemuBackupGetIncrementalMoment(const char *name)
{
virDomainCheckpointDefPtr checkpoint = NULL;
if (!(checkpoint = virDomainCheckpointDefNew()))
abort();
checkpoint->disks = g_new0(virDomainCheckpointDiskDef, 1);
checkpoint->ndisks = 1;
checkpoint->disks[0].name = g_strdup("testdisk");
checkpoint->disks[0].type = VIR_DOMAIN_CHECKPOINT_TYPE_BITMAP;
checkpoint->parent.name = g_strdup(name);
return (virDomainMomentDefPtr) checkpoint;
}
static virDomainMomentDefPtr *
testQemuBackupGetIncremental(const char *incFrom)
{
const char *checkpoints[] = {"current", "d", "c", "b", "a"};
virDomainMomentDefPtr *incr;
size_t i;
incr = g_new0(virDomainMomentDefPtr, G_N_ELEMENTS(checkpoints) + 1);
for (i = 0; i < G_N_ELEMENTS(checkpoints); i++) {
incr[i] = testQemuBackupGetIncrementalMoment(checkpoints[i]);
if (STREQ(incFrom, checkpoints[i]))
break;
}
return incr;
}
static const char *backupDataPrefix = "qemublocktestdata/backupmerge/";
struct testQemuBackupIncrementalBitmapCalculateData {
@ -791,10 +732,10 @@ testQemuBackupIncrementalBitmapCalculate(const void *opaque)
const struct testQemuBackupIncrementalBitmapCalculateData *data = opaque;
g_autoptr(virJSONValue) nodedatajson = NULL;
g_autoptr(virHashTable) nodedata = NULL;
g_autoptr(virJSONValue) mergebitmaps = NULL;
g_autofree char *actual = NULL;
g_autoptr(virJSONValue) actions = virJSONValueNewArray();
g_autofree char *expectpath = NULL;
g_autoptr(testMomentList) incremental = NULL;
g_autoptr(virStorageSource) target = NULL;
g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
expectpath = g_strdup_printf("%s/%s%s-out.json", abs_srcdir,
backupDataPrefix, data->name);
@ -808,19 +749,24 @@ testQemuBackupIncrementalBitmapCalculate(const void *opaque)
return -1;
}
incremental = testQemuBackupGetIncremental(data->incremental);
if (!(target = virStorageSourceNew()))
return -1;
if ((mergebitmaps = qemuBackupDiskPrepareOneBitmapsChain(incremental,
data->chain,
nodedata,
"testdisk"))) {
if (!(actual = virJSONValueToString(mergebitmaps, true)))
target->nodeformat = g_strdup_printf("target_node");
if (qemuBackupDiskPrepareOneBitmapsChain(data->chain,
target,
"target-bitmap-name",
data->incremental,
actions,
nodedata) >= 0) {
if (virJSONValueToBuffer(actions, &buf, true) < 0)
return -1;
} else {
actual = g_strdup("NULL\n");
virBufferAddLit(&buf, "NULL\n");
}
return virTestCompareToFile(actual, expectpath);
return virTestCompareToFile(virBufferCurrentContent(&buf), expectpath);
}

4
tests/qemublocktestdata/backupmerge/empty-out.json
View File

@ -1 +1,3 @@
NULL
[
]