diff --git a/src/libvirt.c b/src/libvirt.c
index 5d54cb595b..b6c99c59c2 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -19669,7 +19669,8 @@ virDomainBlockPull(virDomainPtr dom, const char *disk,
* virDomainBlockRebase:
* @dom: pointer to domain object
* @disk: path to the block device, or device shorthand
- * @base: path to backing file to keep, or NULL for no backing file
+ * @base: path to backing file to keep, or device shorthand,
+ * or NULL for no backing file
* @bandwidth: (optional) specify copy bandwidth limit in MiB/s
* @flags: bitwise-OR of virDomainBlockRebaseFlags
*
@@ -19731,6 +19732,14 @@ virDomainBlockPull(virDomainPtr dom, const char *disk,
* can be found by calling virDomainGetXMLDesc() and inspecting
* elements within //domain/devices/disk.
*
+ * The @base parameter can be either a path to a file within the backing
+ * chain, or the device target shorthand (the
+ * sub-element, such as "vda") followed by an index to the backing chain
+ * enclosed in square brackets. Backing chain indexes can be found by
+ * inspecting //disk//backingStore/@index in the domain XML. Thus, for
+ * example, "vda[3]" refers to the backing store with index equal to "3"
+ * in the chain of disk "vda".
+ *
* The maximum bandwidth (in MiB/s) that will be used to do the copy can be
* specified with the bandwidth parameter. If set to 0, libvirt will choose a
* suitable default. Some hypervisors do not support this feature and will
@@ -19793,9 +19802,10 @@ virDomainBlockRebase(virDomainPtr dom, const char *disk,
* virDomainBlockCommit:
* @dom: pointer to domain object
* @disk: path to the block device, or device shorthand
- * @base: path to backing file to merge into, or NULL for default
+ * @base: path to backing file to merge into, or device shorthand,
+ * or NULL for default
* @top: path to file within backing chain that contains data to be merged,
- * or NULL to merge all possible data
+ * or device shorthand, or NULL to merge all possible data
* @bandwidth: (optional) specify commit bandwidth limit in MiB/s
* @flags: bitwise-OR of virDomainBlockCommitFlags
*
@@ -19845,6 +19855,14 @@ virDomainBlockRebase(virDomainPtr dom, const char *disk,
* can be found by calling virDomainGetXMLDesc() and inspecting
* elements within //domain/devices/disk.
*
+ * The @base and @top parameters can be either paths to files within the
+ * backing chain, or the device target shorthand (the
+ * sub-element, such as "vda") followed by an index to the backing chain
+ * enclosed in square brackets. Backing chain indexes can be found by
+ * inspecting //disk//backingStore/@index in the domain XML. Thus, for
+ * example, "vda[3]" refers to the backing store with index equal to "3"
+ * in the chain of disk "vda".
+ *
* The maximum bandwidth (in MiB/s) that will be used to do the commit can be
* specified with the bandwidth parameter. If set to 0, libvirt will choose a
* suitable default. Some hypervisors do not support this feature and will
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 53dbdb4e8f..4cee2eb06d 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1829,6 +1829,7 @@ virStorageFileGetMetadataFromBuf;
virStorageFileGetMetadataFromFD;
virStorageFileGetSCSIKey;
virStorageFileIsClusterFS;
+virStorageFileParseChainIndex;
virStorageFileProbeFormat;
virStorageFileProbeFormatFromBuf;
virStorageFileResize;
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 700310013c..67ba48734a 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -14854,6 +14854,8 @@ qemuDomainBlockJobImpl(virDomainObjPtr vm,
virObjectEventPtr event = NULL;
int idx;
virDomainDiskDefPtr disk;
+ virStorageSourcePtr baseSource = NULL;
+ unsigned int baseIndex = 0;
if (!virDomainObjIsActive(vm)) {
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
@@ -14915,12 +14917,17 @@ qemuDomainBlockJobImpl(virDomainObjPtr vm,
goto endjob;
}
+ if (base &&
+ (virStorageFileParseChainIndex(disk->dst, base, &baseIndex) < 0 ||
+ !(baseSource = virStorageFileChainLookup(&disk->src,
+ disk->src.backingStore,
+ base, baseIndex, NULL))))
+ goto endjob;
+
qemuDomainObjEnterMonitor(driver, vm);
- /* XXX - libvirt should really be tracking the backing file chain
- * itself, and validating that base is on the chain, rather than
- * relying on qemu to do this. */
- ret = qemuMonitorBlockJob(priv->mon, device, base, bandwidth, info, mode,
- async);
+ ret = qemuMonitorBlockJob(priv->mon, device,
+ baseIndex ? baseSource->path : base,
+ bandwidth, info, mode, async);
qemuDomainObjExitMonitor(driver, vm);
if (ret < 0)
goto endjob;
@@ -15274,8 +15281,11 @@ qemuDomainBlockPull(virDomainPtr dom, const char *path, unsigned long bandwidth,
static int
-qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base,
- const char *top, unsigned long bandwidth,
+qemuDomainBlockCommit(virDomainPtr dom,
+ const char *path,
+ const char *base,
+ const char *top,
+ unsigned long bandwidth,
unsigned int flags)
{
virQEMUDriverPtr driver = dom->conn->privateData;
@@ -15286,7 +15296,9 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base,
int idx;
virDomainDiskDefPtr disk = NULL;
virStorageSourcePtr topSource;
+ unsigned int topIndex = 0;
virStorageSourcePtr baseSource;
+ unsigned int baseIndex = 0;
const char *top_parent = NULL;
bool clean_access = false;
@@ -15327,12 +15339,15 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base,
if (qemuDomainDetermineDiskChain(driver, vm, disk, false) < 0)
goto endjob;
- if (!top) {
+ if (!top)
topSource = &disk->src;
- } else if (!(topSource = virStorageFileChainLookup(disk->src.backingStore,
- top, &top_parent))) {
+ else if (virStorageFileParseChainIndex(disk->dst, top, &topIndex) < 0 ||
+ !(topSource = virStorageFileChainLookup(&disk->src,
+ disk->src.backingStore,
+ top, topIndex,
+ &top_parent)))
goto endjob;
- }
+
if (!topSource->backingStore) {
virReportError(VIR_ERR_INVALID_ARG,
_("top '%s' in chain for '%s' has no backing file"),
@@ -15342,7 +15357,9 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base,
if (!base && (flags & VIR_DOMAIN_BLOCK_COMMIT_SHALLOW))
baseSource = topSource->backingStore;
- else if (!(baseSource = virStorageFileChainLookup(topSource, base, NULL)))
+ else if (virStorageFileParseChainIndex(disk->dst, base, &baseIndex) < 0 ||
+ !(baseSource = virStorageFileChainLookup(&disk->src, topSource,
+ base, baseIndex, NULL)))
goto endjob;
if ((flags & VIR_DOMAIN_BLOCK_COMMIT_SHALLOW) &&
@@ -15377,8 +15394,9 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base,
* thing if the user specified a relative name). */
qemuDomainObjEnterMonitor(driver, vm);
ret = qemuMonitorBlockCommit(priv->mon, device,
- top ? top : topSource->path,
- base ? base : baseSource->path, bandwidth);
+ top && !topIndex ? top : topSource->path,
+ base && !baseIndex ? base : baseSource->path,
+ bandwidth);
qemuDomainObjExitMonitor(driver, vm);
endjob:
diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
index 7ceb8ff695..1ce0fa1bc5 100644
--- a/src/util/virstoragefile.c
+++ b/src/util/virstoragefile.c
@@ -1507,33 +1507,86 @@ int virStorageFileGetSCSIKey(const char *path,
}
#endif
-/* Given a CHAIN, look for the backing file NAME within the chain and
- * return its canonical name. Pass NULL for NAME to find the base of
- * the chain. If META is not NULL, set *META to the point in the
- * chain that describes NAME (or to NULL if the backing element is not
- * a file). If PARENT is not NULL, set *PARENT to the preferred name
- * of the parent (or to NULL if NAME matches the start of the chain).
- * Since the results point within CHAIN, they must not be
- * independently freed. Reports an error and returns NULL if NAME is
- * not found. */
+int
+virStorageFileParseChainIndex(const char *diskTarget,
+ const char *name,
+ unsigned int *chainIndex)
+{
+ char **strings = NULL;
+ unsigned int idx = 0;
+ char *suffix;
+ int ret = 0;
+
+ *chainIndex = 0;
+
+ if (name && diskTarget)
+ strings = virStringSplit(name, "[", 2);
+
+ if (virStringListLength(strings) != 2)
+ goto cleanup;
+
+ if (virStrToLong_ui(strings[1], &suffix, 10, &idx) < 0 ||
+ STRNEQ(suffix, "]"))
+ goto cleanup;
+
+ if (STRNEQ(diskTarget, strings[0])) {
+ virReportError(VIR_ERR_INVALID_ARG,
+ _("requested target '%s' does not match target '%s'"),
+ strings[0], diskTarget);
+ ret = -1;
+ goto cleanup;
+ }
+
+ *chainIndex = idx;
+
+ cleanup:
+ virStringFreeList(strings);
+ return ret;
+}
+
+/* Given a @chain, look for the backing store @name within the chain starting
+ * from @startFrom or @chain if @startFrom is NULL and return that location
+ * within the chain. @chain must always point to the top of the chain. Pass
+ * NULL for @name and 0 for @idx to find the base of the chain. Pass nonzero
+ * @idx to find the backing source according to its position in the backing
+ * chain. If @parent is not NULL, set *@parent to the preferred name of the
+ * parent (or to NULL if @name matches the start of the chain). Since the
+ * results point within @chain, they must not be independently freed.
+ * Reports an error and returns NULL if @name is not found.
+ */
virStorageSourcePtr
virStorageFileChainLookup(virStorageSourcePtr chain,
+ virStorageSourcePtr startFrom,
const char *name,
+ unsigned int idx,
const char **parent)
{
const char *start = chain->path;
const char *tmp;
const char *parentDir = ".";
bool nameIsFile = virStorageIsFile(name);
+ size_t i;
if (!parent)
parent = &tmp;
-
*parent = NULL;
+
+ i = 0;
+ if (startFrom) {
+ while (chain && chain != startFrom) {
+ chain = chain->backingStore;
+ i++;
+ }
+ }
+
while (chain) {
- if (!name) {
+ if (!name && !idx) {
if (!chain->backingStore)
break;
+ } else if (idx) {
+ VIR_DEBUG("%zu: %s", i, chain->path);
+ if (idx == i)
+ break;
} else {
if (STREQ(name, chain->relPath))
break;
@@ -1550,6 +1603,7 @@ virStorageFileChainLookup(virStorageSourcePtr chain,
*parent = chain->path;
parentDir = chain->relDir;
chain = chain->backingStore;
+ i++;
}
if (!chain)
@@ -1557,7 +1611,11 @@ virStorageFileChainLookup(virStorageSourcePtr chain,
return chain;
error:
- if (name) {
+ if (idx) {
+ virReportError(VIR_ERR_INVALID_ARG,
+ _("could not find backing store %u in chain for '%s'"),
+ idx, start);
+ } else if (name) {
virReportError(VIR_ERR_INVALID_ARG,
_("could not find image '%s' in chain for '%s'"),
name, start);
diff --git a/src/util/virstoragefile.h b/src/util/virstoragefile.h
index 82198e5edb..148776ea8a 100644
--- a/src/util/virstoragefile.h
+++ b/src/util/virstoragefile.h
@@ -281,8 +281,15 @@ virStorageSourcePtr virStorageFileGetMetadataFromBuf(const char *path,
int virStorageFileChainGetBroken(virStorageSourcePtr chain,
char **broken_file);
+int virStorageFileParseChainIndex(const char *diskTarget,
+ const char *name,
+ unsigned int *chainIndex)
+ ATTRIBUTE_NONNULL(3);
+
virStorageSourcePtr virStorageFileChainLookup(virStorageSourcePtr chain,
+ virStorageSourcePtr startFrom,
const char *name,
+ unsigned int idx,
const char **parent)
ATTRIBUTE_NONNULL(1);
diff --git a/tests/virstoragetest.c b/tests/virstoragetest.c
index e730b8e4d7..018469a68a 100644
--- a/tests/virstoragetest.c
+++ b/tests/virstoragetest.c
@@ -413,7 +413,9 @@ testStorageChain(const void *args)
struct testLookupData
{
virStorageSourcePtr chain;
+ const char *target;
const char *name;
+ unsigned int expIndex;
const char *expResult;
virStorageSourcePtr expMeta;
const char *expParent;
@@ -426,9 +428,22 @@ testStorageLookup(const void *args)
int ret = 0;
virStorageSourcePtr result;
const char *actualParent;
+ unsigned int idx;
+
+ if (virStorageFileParseChainIndex(data->target, data->name, &idx) < 0 &&
+ data->expIndex) {
+ fprintf(stderr, "call should not have failed\n");
+ ret = -1;
+ }
+ if (idx != data->expIndex) {
+ fprintf(stderr, "index: expected %u, got %u\n", data->expIndex, idx);
+ ret = -1;
+ }
/* Test twice to ensure optional parameter doesn't cause NULL deref. */
- result = virStorageFileChainLookup(data->chain, data->name, NULL);
+ result = virStorageFileChainLookup(data->chain, NULL,
+ idx ? NULL : data->name,
+ idx, NULL);
if (!data->expResult) {
if (!virGetLastError()) {
@@ -455,7 +470,8 @@ testStorageLookup(const void *args)
ret = -1;
}
- result = virStorageFileChainLookup(data->chain, data->name, &actualParent);
+ result = virStorageFileChainLookup(data->chain, data->chain,
+ data->name, idx, &actualParent);
if (!data->expResult)
virResetLastError();
@@ -878,14 +894,16 @@ mymain(void)
goto cleanup;
}
-#define TEST_LOOKUP(id, name, result, meta, parent) \
- do { \
- struct testLookupData data2 = { chain, name, \
- result, meta, parent, }; \
- if (virtTestRun("Chain lookup " #id, \
- testStorageLookup, &data2) < 0) \
- ret = -1; \
+#define TEST_LOOKUP_TARGET(id, target, name, index, result, meta, parent) \
+ do { \
+ struct testLookupData data2 = { chain, target, name, index, \
+ result, meta, parent, }; \
+ if (virtTestRun("Chain lookup " #id, \
+ testStorageLookup, &data2) < 0) \
+ ret = -1; \
} while (0)
+#define TEST_LOOKUP(id, name, result, meta, parent) \
+ TEST_LOOKUP_TARGET(id, NULL, name, 0, result, meta, parent)
TEST_LOOKUP(0, "bogus", NULL, NULL, NULL);
TEST_LOOKUP(1, "wrap", chain->path, chain, NULL);
@@ -969,6 +987,21 @@ mymain(void)
TEST_LOOKUP(25, NULL, chain->backingStore->backingStore->path,
chain->backingStore->backingStore, chain->backingStore->path);
+ TEST_LOOKUP_TARGET(26, "vda", "bogus[1]", 0, NULL, NULL, NULL);
+ TEST_LOOKUP_TARGET(27, "vda", "vda[-1]", 0, NULL, NULL, NULL);
+ TEST_LOOKUP_TARGET(28, "vda", "vda[1][1]", 0, NULL, NULL, NULL);
+ TEST_LOOKUP_TARGET(29, "vda", "wrap", 0, chain->path, chain, NULL);
+ TEST_LOOKUP_TARGET(30, "vda", "vda[0]", 0, NULL, NULL, NULL);
+ TEST_LOOKUP_TARGET(31, "vda", "vda[1]", 1,
+ chain->backingStore->path,
+ chain->backingStore,
+ chain->path);
+ TEST_LOOKUP_TARGET(32, "vda", "vda[2]", 2,
+ chain->backingStore->backingStore->path,
+ chain->backingStore->backingStore,
+ chain->backingStore->path);
+ TEST_LOOKUP_TARGET(33, "vda", "vda[3]", 3, NULL, NULL, NULL);
+
cleanup:
/* Final cleanup */
virStorageSourceFree(chain);