[libvirt] [PATCH v8 5/5] virstoragefile: Convert storage source backingStore into backingStores

[John Ferlan]

From: Matthias Gatto <matthias.gatto at outscale.com>

Convert the storage source backingStore pointer into an array of
virStorageSourcePtr.

This patch will rename src->backingStore to src->backingStores, add an
nbackingStores, and adjust the code Get and Set functions to handle the
the array.

virStorageSourceSetBackingStore can expand the size of src->backingStores.

Signed-off-by: Matthias Gatto <matthias.gatto at outscale.com>
Signed-off-by: John Ferlan <jferlan at redhat.com>
---
 src/util/virstoragefile.c | 61 ++++++++++++++++++++++++++++++-----------------
 src/util/virstoragefile.h |  3 ++-
 2 files changed, 41 insertions(+), 23 deletions(-)

diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
index 1d96d7a..b917eb6 100644
--- a/src/util/virstoragefile.c
+++ b/src/util/virstoragefile.c
@@ -1813,11 +1813,10 @@ virStorageSourcePoolDefCopy(const virStorageSourcePoolDef *src)
 /**
  * virStorageSourceGetBackingStore:
  * @src: virStorageSourcePtr containing the backing stores
- * @pos: presently unused
+ * @pos: position of the backing store to get
  *
- * Return the @src backingStore pointer at @pos. For now, @pos is
- * expected to be 0. A future patch will use @pos index into an array
- * of storage backingStore pointers
+ * Return the @src backingStore pointer at @pos in the array of
+ * storage backingStores pointers
  *
  * Returns:
  * A pointer to the storage source backingStore @pos or
@@ -1827,9 +1826,9 @@ virStorageSourcePtr
 virStorageSourceGetBackingStore(const virStorageSource *src,
                                 size_t pos)
 {
-    if (!src || pos > 0)
+    if (!src || !src->backingStores || pos >= src->nBackingStores)
         return NULL;
-    return src->backingStore;
+    return src->backingStores[pos];
 }
 
 
@@ -1837,11 +1836,12 @@ virStorageSourceGetBackingStore(const virStorageSource *src,
  * virStorageSourceSetBackingStore:
  * @src: virStorageSourcePtr to hold @backingStore
  * @backingStore - Pointer to the backingStore to store
- * @pos - presently unused
+ * @pos: position of the backing store to store
  *
- * Set @backingStore in @src at @pos in src->backingStore. For now, pos
- * is expected to be 0. A future patch will use pos as the position in
- * the array of storage backingStore pointers
+ * Set @backingStore in @src at @pos in src->backingStores. If the
+ * backingStores array does not have the space to contain @backingStore,
+ * expand src->backingStores. If the entry at @pos already exists, then
+ * free it first before replacing with the new @backingStore.
  *
  * Returns:
  * 0 on success, -1 on failure
@@ -1851,10 +1851,18 @@ virStorageSourceSetBackingStore(virStorageSourcePtr src,
                                 virStorageSourcePtr backingStore,
                                 size_t pos)
 {
-    if (pos > 0)
+    if (!src)
         return -1;
 
-    src->backingStore = backingStore;
+    if (pos >= src->nBackingStores) {
+        int nbr = pos - src->nBackingStores + 1;
+        if (VIR_EXPAND_N(src->backingStores, src->nBackingStores, nbr) < 0)
+            return -1;
+    }
+
+    if (src->backingStores[pos])
+        virStorageSourceFree(src->backingStores[pos]);
+    src->backingStores[pos] = backingStore;
     return 0;
 }
 
@@ -1873,6 +1881,7 @@ virStorageSourceCopy(const virStorageSource *src,
                      bool backingChain)
 {
     virStorageSourcePtr ret = NULL;
+    size_t i;
 
     if (VIR_ALLOC(ret) < 0)
         return NULL;
@@ -1885,6 +1894,7 @@ virStorageSourceCopy(const virStorageSource *src,
     ret->physical = src->physical;
     ret->readonly = src->readonly;
     ret->shared = src->shared;
+    ret->nBackingStores = src->nBackingStores;
 
     /* storage driver metadata are not copied */
     ret->drv = NULL;
@@ -1933,15 +1943,17 @@ virStorageSourceCopy(const virStorageSource *src,
         !(ret->auth = virStorageAuthDefCopy(src->auth)))
         goto error;
 
-    if (backingChain) {
-        virStorageSourcePtr backingStore =
-            virStorageSourceGetBackingStore(src, 0);
-        virStorageSourcePtr backingStoreCopy =
-            virStorageSourceCopy(backingStore, true);
+    for (i = 0; i < src->nBackingStores; i++) {
+        if (backingChain) {
+            virStorageSourcePtr backingStore =
+                virStorageSourceGetBackingStore(src, i);
+            virStorageSourcePtr backingStoreCopy =
+                virStorageSourceCopy(backingStore, true);
 
-        if (!backingStoreCopy ||
-            virStorageSourceSetBackingStore(ret, backingStoreCopy, 0) < 0)
-            goto error;
+            if (!backingStoreCopy ||
+                virStorageSourceSetBackingStore(ret, backingStoreCopy, i) < 0)
+                goto error;
+        }
     }
 
     return ret;
@@ -2073,6 +2085,8 @@ virStorageSourceIsEmpty(virStorageSourcePtr src)
 void
 virStorageSourceBackingStoreClear(virStorageSourcePtr def)
 {
+    size_t i;
+
     if (!def)
         return;
 
@@ -2080,8 +2094,11 @@ virStorageSourceBackingStoreClear(virStorageSourcePtr def)
     VIR_FREE(def->backingStoreRaw);
 
     /* recursively free backing chain */
-    virStorageSourceFree(virStorageSourceGetBackingStore(def, 0));
-    ignore_value(virStorageSourceSetBackingStore(def, NULL, 0));
+    for (i = 0; i < def->nBackingStores; i++)
+        virStorageSourceFree(virStorageSourceGetBackingStore(def, i));
+    if (def->nBackingStores > 0)
+        VIR_FREE(def->backingStores);
+    def->nBackingStores = 0;
 }
 
 
diff --git a/src/util/virstoragefile.h b/src/util/virstoragefile.h
index ce1cb5d..290c20f 100644
--- a/src/util/virstoragefile.h
+++ b/src/util/virstoragefile.h
@@ -270,7 +270,8 @@ struct _virStorageSource {
     bool shared;
 
     /* backing chain of the storage source */
-    virStorageSourcePtr backingStore;
+    virStorageSourcePtr *backingStores;
+    size_t      nBackingStores;
 
     /* metadata for storage driver access to remote and local volumes */
     virStorageDriverDataPtr drv;
-- 
2.5.0