[libvirt] [PATCH] rbd: Use rbd_create3 to create RBD format 2 images by default

[Wido den Hollander]

This new RBD format supports snapshotting and cloning. By having
libvirt create images in format 2 end-users of the created images
can benefit of the new RBD format.

Older versions of libvirt can work with this new RBD format as long
as librbd supports format 2, something that all recent versions of
librbd do.

Signed-off-by: Wido den Hollander <wido at widodh.nl>
---
 src/storage/storage_backend_rbd.c |   23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/storage/storage_backend_rbd.c b/src/storage/storage_backend_rbd.c
index 4b6f18c..f3dd7a0 100644
--- a/src/storage/storage_backend_rbd.c
+++ b/src/storage/storage_backend_rbd.c
@@ -435,6 +435,26 @@ cleanup:
     return ret;
 }
 
+static int virStorageBackendRBDCreateImage(rados_ioctx_t io,
+                                           char *name, long capacity)
+{
+    int order = 0;
+    #if LIBRBD_VERSION_CODE > 260
+    uint64_t features = 3;
+    uint64_t stripe_count = 1;
+    uint64_t stripe_unit = 4194304;
+
+    if (rbd_create3(io, name, capacity, features, &order,
+                    stripe_count, stripe_unit) < 0) {
+    #else
+    if (rbd_create(io, name, capacity, &order) < 0) {
+    #endif
+        return -1;
+    }
+
+    return 0;
+}
+
 static int virStorageBackendRBDCreateVol(virConnectPtr conn,
                                          virStoragePoolObjPtr pool,
                                          virStorageVolDefPtr vol)
@@ -442,7 +462,6 @@ static int virStorageBackendRBDCreateVol(virConnectPtr conn,
     virStorageBackendRBDState ptr;
     ptr.cluster = NULL;
     ptr.ioctx = NULL;
-    int order = 0;
     int ret = -1;
 
     VIR_DEBUG("Creating RBD image %s/%s with size %llu",
@@ -467,7 +486,7 @@ static int virStorageBackendRBDCreateVol(virConnectPtr conn,
         goto cleanup;
     }
 
-    if (rbd_create(ptr.ioctx, vol->name, vol->capacity, &order) < 0) {
+    if (virStorageBackendRBDCreateImage(ptr.ioctx, vol->name, vol->capacity) < 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("failed to create volume '%s/%s'"),
                        pool->def->source.name,
-- 
1.7.9.5