[libvirt] [PATCH 18/35] qemu: block: Always set discard for storage nodes

[Peter Krempa]

Enabling discard for the storage node allows the format drivers to
discard snapshots and other things, while configuration of the format
layer actually decides whether to actually discard data on request from
the host.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 src/qemu/qemu_block.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_block.c b/src/qemu/qemu_block.c
index b1f495b731..6e76571796 100644
--- a/src/qemu/qemu_block.c
+++ b/src/qemu/qemu_block.c
@@ -1163,7 +1163,10 @@ qemuBlockStorageSourceGetBackendProps(virStorageSourcePtr src,
         if (qemuBlockStorageSourceGetBlockdevGetCacheProps(src, fileprops) < 0)
             goto cleanup;

-        if (virJSONValueObjectAdd(fileprops, "b:read-only", src->readonly, NULL) < 0)
+        if (virJSONValueObjectAdd(fileprops,
+                                  "b:read-only", src->readonly,
+                                  "s:discard", "unmap",
+                                  NULL) < 0)
             goto cleanup;
     }

-- 
2.16.2