qemu: block: Implement helpers for dealing with bitmaps during block commit

qemuBlockBitmapsHandleCommitStart prepares for disabling the bitmaps in
the 'base' of the commit job so that the bitmaps are not dirtied by the
commit job. This needs to be done prior to start of the commit job.

qemuBlockBitmapsHandleCommitFinish then calculates the necessary merges
that agregate all the bitmaps between the commited images and write them
into the base bitmap.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Peter Krempa 2020-03-02 14:40:18 +01:00
parent f8389505aa
commit 1753f60550
2 changed files with 233 additions and 0 deletions

View File

@ -2990,6 +2990,225 @@ qemuBlockBitmapsHandleBlockcopy(virStorageSourcePtr src,
}
/**
* @topsrc: virStorageSource representing 'top' of the job
* @basesrc: virStorageSource representing 'base' of the job
* @blockNamedNodeData: hash table containing data about bitmaps
* @actions: filled with arguments for a 'transaction' command
* @disabledBitmapsBase: filled with a list of bitmap names which must be disabled
*
* Prepares data for correctly handling bitmaps during the start of a commit
* job. The bitmaps in the 'base' image must be disabled, so that the writes
* done by the blockjob don't dirty the enabled bitmaps.
*
* @actions and @disabledBitmapsBase are untouched if no bitmaps need
* to be disabled.
*/
int
qemuBlockBitmapsHandleCommitStart(virStorageSourcePtr topsrc,
virStorageSourcePtr basesrc,
virHashTablePtr blockNamedNodeData,
virJSONValuePtr *actions,
char ***disabledBitmapsBase)
{
g_autoptr(virJSONValue) act = virJSONValueNewArray();
VIR_AUTOSTRINGLIST bitmaplist = NULL;
size_t curbitmapstr = 0;
qemuBlockNamedNodeDataPtr entry;
bool disable_bitmaps = false;
size_t i;
if (!(entry = virHashLookup(blockNamedNodeData, basesrc->nodeformat)))
return 0;
bitmaplist = g_new0(char *, entry->nbitmaps);
for (i = 0; i < entry->nbitmaps; i++) {
qemuBlockNamedNodeDataBitmapPtr bitmap = entry->bitmaps[i];
if (!bitmap->recording || bitmap->inconsistent ||
!qemuBlockBitmapChainIsValid(topsrc, bitmap->name, blockNamedNodeData))
continue;
disable_bitmaps = true;
if (qemuMonitorTransactionBitmapDisable(act, basesrc->nodeformat,
bitmap->name) < 0)
return -1;
bitmaplist[curbitmapstr++] = g_strdup(bitmap->name);
}
if (disable_bitmaps) {
*actions = g_steal_pointer(&act);
*disabledBitmapsBase = g_steal_pointer(&bitmaplist);
}
return 0;
}
struct qemuBlockBitmapsHandleCommitData {
bool skip;
bool create;
bool enable;
const char *basenode;
virJSONValuePtr merge;
unsigned long long granularity;
bool persistent;
};
static void
qemuBlockBitmapsHandleCommitDataFree(void *opaque)
{
struct qemuBlockBitmapsHandleCommitData *data = opaque;
virJSONValueFree(data->merge);
g_free(data);
}
static int
qemuBlockBitmapsHandleCommitFinishIterate(void *payload,
const void *entryname,
void *opaque)
{
struct qemuBlockBitmapsHandleCommitData *data = payload;
const char *bitmapname = entryname;
virJSONValuePtr actions = opaque;
if (data->skip)
return 0;
if (data->create) {
if (qemuMonitorTransactionBitmapAdd(actions, data->basenode, bitmapname,
data->persistent, !data->enable,
data->granularity) < 0)
return -1;
} else {
if (data->enable &&
qemuMonitorTransactionBitmapEnable(actions, data->basenode, bitmapname) < 0)
return -1;
}
if (data->merge &&
qemuMonitorTransactionBitmapMerge(actions, data->basenode, bitmapname,
&data->merge) < 0)
return -1;
return 0;
}
/**
* @topsrc: virStorageSource representing 'top' of the job
* @basesrc: virStorageSource representing 'base' of the job
* @blockNamedNodeData: hash table containing data about bitmaps
* @actions: filled with arguments for a 'transaction' command
* @disabledBitmapsBase: bitmap names which were disabled
*
* Calculates the necessary bitmap merges/additions/enablements to properly
* handle commit of images from 'top' into 'base'. The necessary operations
* in the form of arguments of the 'transaction' command are filled into
* 'actions' if there is anything to do. Otherwise NULL is returned.
*/
int
qemuBlockBitmapsHandleCommitFinish(virStorageSourcePtr topsrc,
virStorageSourcePtr basesrc,
virHashTablePtr blockNamedNodeData,
virJSONValuePtr *actions,
char **disabledBitmapsBase)
{
g_autoptr(virJSONValue) act = virJSONValueNewArray();
virStorageSourcePtr n;
qemuBlockNamedNodeDataPtr entry;
g_autoptr(virHashTable) commitdata = NULL;
struct qemuBlockBitmapsHandleCommitData *bitmapdata;
size_t i;
commitdata = virHashNew(qemuBlockBitmapsHandleCommitDataFree);
for (n = topsrc; n != basesrc; n = n->backingStore) {
if (!(entry = virHashLookup(blockNamedNodeData, n->nodeformat)))
continue;
for (i = 0; i < entry->nbitmaps; i++) {
qemuBlockNamedNodeDataBitmapPtr bitmap = entry->bitmaps[i];
if (!(bitmapdata = virHashLookup(commitdata, bitmap->name))) {
bitmapdata = g_new0(struct qemuBlockBitmapsHandleCommitData, 1);
/* we must mirror the state of the topmost bitmap and merge
* everything else */
bitmapdata->create = true;
bitmapdata->enable = bitmap->recording;
bitmapdata->basenode = basesrc->nodeformat;
bitmapdata->merge = virJSONValueNewArray();
bitmapdata->granularity = bitmap->granularity;
bitmapdata->persistent = bitmap->persistent;
if (virHashAddEntry(commitdata, bitmap->name, bitmapdata) < 0) {
qemuBlockBitmapsHandleCommitDataFree(bitmapdata);
return -1;
}
}
if (bitmap->inconsistent ||
!qemuBlockBitmapChainIsValid(topsrc, bitmap->name, blockNamedNodeData))
bitmapdata->skip = true;
if (qemuMonitorTransactionBitmapMergeSourceAddBitmap(bitmapdata->merge,
n->nodeformat,
bitmap->name) < 0)
return -1;
}
}
if ((entry = virHashLookup(blockNamedNodeData, basesrc->nodeformat))) {
/* note that all bitmaps in 'base' were disabled when commit was started */
for (i = 0; i < entry->nbitmaps; i++) {
qemuBlockNamedNodeDataBitmapPtr bitmap = entry->bitmaps[i];
if ((bitmapdata = virHashLookup(commitdata, bitmap->name))) {
bitmapdata->create = false;
} else {
if (disabledBitmapsBase) {
char **disabledbitmaps;
for (disabledbitmaps = disabledBitmapsBase; *disabledbitmaps; disabledbitmaps++) {
if (STREQ(*disabledBitmapsBase, bitmap->name)) {
bitmapdata = g_new0(struct qemuBlockBitmapsHandleCommitData, 1);
bitmapdata->create = false;
bitmapdata->enable = true;
bitmapdata->basenode = basesrc->nodeformat;
bitmapdata->granularity = bitmap->granularity;
bitmapdata->persistent = bitmap->persistent;
if (virHashAddEntry(commitdata, bitmap->name, bitmapdata) < 0) {
qemuBlockBitmapsHandleCommitDataFree(bitmapdata);
return -1;
}
break;
}
}
}
}
}
}
if (virHashForEach(commitdata, qemuBlockBitmapsHandleCommitFinishIterate, act) < 0)
return -1;
if (virJSONValueArraySize(act) > 0)
*actions = g_steal_pointer(&act);
return 0;
}
/**
* qemuBlockReopenFormat:
* @vm: domain object

View File

@ -232,6 +232,20 @@ qemuBlockBitmapsHandleBlockcopy(virStorageSourcePtr src,
bool shallow,
virJSONValuePtr *actions);
int
qemuBlockBitmapsHandleCommitStart(virStorageSourcePtr topsrc,
virStorageSourcePtr basesrc,
virHashTablePtr blockNamedNodeData,
virJSONValuePtr *actions,
char ***disabledBitmapsBase);
int
qemuBlockBitmapsHandleCommitFinish(virStorageSourcePtr topsrc,
virStorageSourcePtr basesrc,
virHashTablePtr blockNamedNodeData,
virJSONValuePtr *actions,
char **disabledBitmapsBase);
int
qemuBlockReopenReadWrite(virDomainObjPtr vm,
virStorageSourcePtr src,