[libvirt] [PATCH] storage: Add --shrink to qemu-img command when shrinking vol

[John Ferlan]

https://bugzilla.redhat.com/show_bug.cgi?id=1613746

When shrinking the capacity of a qcow2 or luks volume using
the qemu-img program, the --shrink qualifier must be added.

Signed-off-by: John Ferlan <jferlan at redhat.com>
---
 src/storage/storage_util.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/storage/storage_util.c b/src/storage/storage_util.c
index 42a9b6abf0..c936120bf0 100644
--- a/src/storage/storage_util.c
+++ b/src/storage/storage_util.c
@@ -2294,12 +2294,12 @@ storageBackendResizeQemuImg(virStoragePoolObjPtr pool,
      * a multiple of 512 */
     capacity = VIR_ROUND_UP(capacity, 512);
 
-    cmd = virCommandNew(img_tool);
+    cmd = virCommandNewArgList(img_tool, "resize", NULL);
+    if (capacity < vol->target.capacity)
+        virCommandAddArg(cmd, "--shrink");
     if (!vol->target.encryption) {
-        virCommandAddArgList(cmd, "resize", vol->target.path, NULL);
+        virCommandAddArg(cmd, vol->target.path);
     } else {
-        virCommandAddArg(cmd, "resize");
-
         if (storageBackendCreateQemuImgSecretObject(cmd, secretPath,
                                                     secretAlias) < 0)
             goto cleanup;
-- 
2.17.1