libvirt/src/qemu/qemu_block.c
Nikolay Shirokovskiy dd8e40790b qemu: take current async job into account in qemuBlockNodeNamesDetect
Becase it can be called during migration out (namely on cancelling
blockjobs).

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2017-04-27 14:38:29 +02:00

431 lines
12 KiB
C

/*
* qemu_block.c: helper functions for QEMU block subsystem
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include "qemu_block.h"
#include "qemu_domain.h"
#include "viralloc.h"
#include "virstring.h"
#define VIR_FROM_THIS VIR_FROM_QEMU
static void
qemuBlockNodeNameBackingChainDataFree(qemuBlockNodeNameBackingChainDataPtr data)
{
size_t i;
if (!data)
return;
for (i = 0; i < data->nelems; i++)
virJSONValueFree(data->elems[i]);
VIR_FREE(data->nodeformat);
VIR_FREE(data->nodestorage);
VIR_FREE(data->nodebacking);
VIR_FREE(data->qemufilename);
VIR_FREE(data->backingstore);
VIR_FREE(data);
}
static void
qemuBlockNodeNameBackingChainDataHashEntryFree(void *opaque,
const void *name ATTRIBUTE_UNUSED)
{
qemuBlockNodeNameBackingChainDataFree(opaque);
}
struct qemuBlockNodeNameGetBackingChainData {
virHashTablePtr table;
qemuBlockNodeNameBackingChainDataPtr *entries;
size_t nentries;
};
static int
qemuBlockNodeNameDetectProcessByFilename(size_t pos ATTRIBUTE_UNUSED,
virJSONValuePtr item,
void *opaque)
{
struct qemuBlockNodeNameGetBackingChainData *data = opaque;
qemuBlockNodeNameBackingChainDataPtr entry;
const char *file;
if (!(file = virJSONValueObjectGetString(item, "file")))
return 1;
if (!(entry = virHashLookup(data->table, file))) {
if (VIR_ALLOC(entry) < 0)
return -1;
if (VIR_APPEND_ELEMENT_COPY(data->entries, data->nentries, entry) < 0) {
VIR_FREE(entry);
return -1;
}
if (VIR_STRDUP(entry->qemufilename, file) < 0)
return -1;
if (virHashAddEntry(data->table, file, entry) < 0)
return -1;
}
if (VIR_APPEND_ELEMENT(entry->elems, entry->nelems, item) < 0)
return -1;
return 0;
}
static const char *qemuBlockDriversFormat[] = {
"qcow2", "raw", "qcow", "luks", "qed", "bochs", "cloop", "dmg", "parallels",
"vdi", "vhdx", "vmdk", "vpc", "vvfat", NULL};
static const char *qemuBlockDriversStorage[] = {
"file", "iscsi", "nbd", "host_cdrom", "host_device", "ftp", "ftps",
"gluster", "http", "https", "nfs", "rbd", "sheepdog", "ssh", "tftp", NULL};
static bool
qemuBlockDriverMatch(const char *drvname,
const char **drivers)
{
while (*drivers) {
if (STREQ(drvname, *drivers))
return true;
drivers++;
}
return false;
}
static int
qemuBlockNodeNameDetectProcessExtract(qemuBlockNodeNameBackingChainDataPtr data)
{
const char *drv;
const char *nodename;
const char *backingstore;
size_t i;
/* Since the only way to construct the backing chain is to look up the files
* by file name, if two disks share a backing image we can't know which node
* belongs to which backing chain. Refuse to detect such chains. */
if (data->nelems > 2)
return 0;
for (i = 0; i < data->nelems; i++) {
drv = virJSONValueObjectGetString(data->elems[i], "drv");
nodename = virJSONValueObjectGetString(data->elems[i], "node-name");
backingstore = virJSONValueObjectGetString(data->elems[i], "backing_file");
if (!drv || !nodename)
continue;
if (qemuBlockDriverMatch(drv, qemuBlockDriversFormat)) {
if (data->nodeformat)
continue;
if (VIR_STRDUP(data->nodeformat, nodename) < 0)
return -1;
/* extract the backing store file name for the protocol layer */
if (VIR_STRDUP(data->backingstore, backingstore) < 0)
return -1;
} else if (qemuBlockDriverMatch(drv, qemuBlockDriversStorage)) {
if (data->nodestorage)
continue;
if (VIR_STRDUP(data->nodestorage, nodename) < 0)
return -1;
}
}
return 0;
}
static int
qemuBlockNodeNameDetectProcessLinkBacking(qemuBlockNodeNameBackingChainDataPtr data,
virHashTablePtr table)
{
qemuBlockNodeNameBackingChainDataPtr backing;
if (!data->backingstore)
return 0;
if (!(backing = virHashLookup(table, data->backingstore)))
return 0;
if (VIR_STRDUP(data->nodebacking, backing->nodeformat) < 0)
return -1;
return 0;
}
static void
qemuBlockNodeNameGetBackingChainDataClearLookup(qemuBlockNodeNameBackingChainDataPtr data)
{
size_t i;
for (i = 0; i < data->nelems; i++)
virJSONValueFree(data->elems[i]);
VIR_FREE(data->elems);
data->nelems = 0;
}
/**
* qemuBlockNodeNameGetBackingChain:
* @json: JSON array of data returned from 'query-named-block-nodes'
*
* Tries to reconstruct the backing chain from @json to allow detection of
* node names that were auto-assigned by qemu. This is a best-effort operation
* and may not be successful. The returned hash table contains the entries as
* qemuBlockNodeNameBackingChainDataPtr accessible by the node name. The fields
* then can be used to recover the full backing chain.
*
* Returns a hash table on success and NULL on failure.
*/
virHashTablePtr
qemuBlockNodeNameGetBackingChain(virJSONValuePtr json)
{
struct qemuBlockNodeNameGetBackingChainData data;
virHashTablePtr nodetable = NULL;
virHashTablePtr ret = NULL;
size_t i;
memset(&data, 0, sizeof(data));
/* hash table keeps the entries accessible by the 'file' in qemu */
if (!(data.table = virHashCreate(50, NULL)))
goto cleanup;
/* first group the named entries by the 'file' field */
if (virJSONValueArrayForeachSteal(json,
qemuBlockNodeNameDetectProcessByFilename,
&data) < 0)
goto cleanup;
/* extract the node names for the format and storage layer */
for (i = 0; i < data.nentries; i++) {
if (qemuBlockNodeNameDetectProcessExtract(data.entries[i]) < 0)
goto cleanup;
}
/* extract the node name for the backing file */
for (i = 0; i < data.nentries; i++) {
if (qemuBlockNodeNameDetectProcessLinkBacking(data.entries[i],
data.table) < 0)
goto cleanup;
}
/* clear JSON data necessary only for the lookup procedure */
for (i = 0; i < data.nentries; i++)
qemuBlockNodeNameGetBackingChainDataClearLookup(data.entries[i]);
/* create hash table hashed by the format node name */
if (!(nodetable = virHashCreate(50,
qemuBlockNodeNameBackingChainDataHashEntryFree)))
goto cleanup;
/* fill the entries */
for (i = 0; i < data.nentries; i++) {
if (!data.entries[i]->nodeformat)
continue;
if (virHashAddEntry(nodetable, data.entries[i]->nodeformat,
data.entries[i]) < 0)
goto cleanup;
/* hash table steals the entry and then frees it by itself */
data.entries[i] = NULL;
}
VIR_STEAL_PTR(ret, nodetable);
cleanup:
virHashFree(data.table);
virHashFree(nodetable);
for (i = 0; i < data.nentries; i++)
qemuBlockNodeNameBackingChainDataFree(data.entries[i]);
VIR_FREE(data.entries);
return ret;
}
static void
qemuBlockDiskClearDetectedNodes(virDomainDiskDefPtr disk)
{
virStorageSourcePtr next = disk->src;
while (next) {
VIR_FREE(next->nodeformat);
VIR_FREE(next->nodebacking);
next = next->backingStore;
}
}
static int
qemuBlockDiskDetectNodes(virDomainDiskDefPtr disk,
const char *parentnode,
virHashTablePtr table)
{
qemuBlockNodeNameBackingChainDataPtr entry = NULL;
virStorageSourcePtr src = disk->src;
/* don't attempt the detection if the top level already has node names */
if (!parentnode || src->nodeformat || src->nodebacking)
return 0;
while (src && parentnode) {
if (!(entry = virHashLookup(table, parentnode)))
break;
if (src->nodeformat || src->nodebacking) {
if (STRNEQ_NULLABLE(src->nodeformat, entry->nodeformat) ||
STRNEQ_NULLABLE(src->nodebacking, entry->nodestorage))
goto error;
break;
} else {
if (VIR_STRDUP(src->nodeformat, entry->nodeformat) < 0 ||
VIR_STRDUP(src->nodebacking, entry->nodestorage) < 0)
goto error;
}
parentnode = entry->nodebacking;
src = src->backingStore;
}
return 0;
error:
qemuBlockDiskClearDetectedNodes(disk);
return -1;
}
int
qemuBlockNodeNamesDetect(virQEMUDriverPtr driver,
virDomainObjPtr vm,
qemuDomainAsyncJob asyncJob)
{
qemuDomainObjPrivatePtr priv = vm->privateData;
virHashTablePtr disktable = NULL;
virHashTablePtr nodenametable = NULL;
virJSONValuePtr data = NULL;
virDomainDiskDefPtr disk;
struct qemuDomainDiskInfo *info;
size_t i;
int ret = -1;
if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_QUERY_NAMED_BLOCK_NODES))
return 0;
if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
return -1;
disktable = qemuMonitorGetBlockInfo(qemuDomainGetMonitor(vm));
data = qemuMonitorQueryNamedBlockNodes(qemuDomainGetMonitor(vm));
if (qemuDomainObjExitMonitor(driver, vm) < 0 || !data || !disktable)
goto cleanup;
if (!(nodenametable = qemuBlockNodeNameGetBackingChain(data)))
goto cleanup;
for (i = 0; i < vm->def->ndisks; i++) {
disk = vm->def->disks[i];
if (!(info = virHashLookup(disktable, disk->info.alias)))
continue;
if (qemuBlockDiskDetectNodes(disk, info->nodename, nodenametable) < 0)
goto cleanup;
}
ret = 0;
cleanup:
virJSONValueFree(data);
virHashFree(nodenametable);
virHashFree(disktable);
return ret;
}
static int
qemuBlockFillNodeData(size_t pos ATTRIBUTE_UNUSED,
virJSONValuePtr item,
void *opaque)
{
virHashTablePtr table = opaque;
const char *name;
if (!(name = virJSONValueObjectGetString(item, "node-name")))
return 1;
if (virHashAddEntry(table, name, item) < 0)
return -1;
return 0;
}
/**
* qemuBlockGetNodeData:
* @data: JSON object returned from query-named-block-nodes
*
* Returns a hash table organized by the node name of the JSON value objects of
* data for given qemu block nodes.
*
* Returns a filled virHashTablePtr on success NULL on error.
*/
virHashTablePtr
qemuBlockGetNodeData(virJSONValuePtr data)
{
virHashTablePtr ret = NULL;
if (!(ret = virHashCreate(50, virJSONValueHashFree)))
return NULL;
if (virJSONValueArrayForeachSteal(data, qemuBlockFillNodeData, ret) < 0)
goto error;
return ret;
error:
virHashFree(ret);
return NULL;
}