[libvirt] [PATCH 4/5] storage: Add helper to retrieve the backing store string of a storage volume
It is necessary for some parts of the code to refresh just data
based on the based on the backing store string. Add a convenience
function that will retrieve this data.
---
src/storage/storage_driver.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
src/storage/storage_driver.h | 3 +++
2 files changed, 47 insertions(+)
diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
index 967776698..ab1dc8f36 100644
--- a/src/storage/storage_driver.c
+++ b/src/storage/storage_driver.c
@@ -3263,6 +3263,50 @@ virStorageFileGetMetadata(virStorageSourcePtr src,
}
+/**
+ * virStorageFileGetBackingStoreStr:
+ * @src: storage object
+ *
+ * Extracts the backing store string as stored in the storage volume described
+ * by @src and returns it to the user. Caller is responsible for freeing it.
+ * In case when the string can't be retrieved or does not exist NULL is
+ * returned.
+ */
+char *
+virStorageFileGetBackingStoreStr(virStorageSourcePtr src)
+{
+ virStorageSourcePtr tmp = NULL;
+ char *buf = NULL;
+ ssize_t headerLen;
+ char *ret = NULL;
+
+ /* exit if we can't load information about the current image */
+ if (!virStorageFileSupportsBackingChainTraversal(src))
+ return NULL;
+
+ if (virStorageFileAccess(src, F_OK) < 0)
+ return NULL;
+
+ if ((headerLen = virStorageFileReadHeader(src, VIR_STORAGE_MAX_HEADER,
+ &buf)) < 0)
+ return NULL;
+
+ if (!(tmp = virStorageSourceCopy(src, false)))
+ goto cleanup;
+
+ if (virStorageFileGetMetadataInternal(tmp, buf, headerLen, NULL) < 0)
+ goto cleanup;
+
+ VIR_STEAL_PTR(ret, tmp->backingStoreRaw);
+
+ cleanup:
+ VIR_FREE(buf);
+ virStorageSourceFree(tmp);
+
+ return ret;
+}
+
+
static int
virStorageAddISCSIPoolSourceHost(virDomainDiskDefPtr def,
virStoragePoolDefPtr pooldef)
diff --git a/src/storage/storage_driver.h b/src/storage/storage_driver.h
index 530bc3388..ade05f715 100644
--- a/src/storage/storage_driver.h
+++ b/src/storage/storage_driver.h
@@ -54,6 +54,9 @@ int virStorageFileGetMetadata(virStorageSourcePtr src,
bool report_broken)
ATTRIBUTE_NONNULL(1);
+char *virStorageFileGetBackingStoreStr(virStorageSourcePtr src)
+ ATTRIBUTE_NONNULL(1);
+
int virStorageTranslateDiskSourcePool(virConnectPtr conn,
virDomainDiskDefPtr def);
--
2.12.2