From: Peter Krempa <pkrempa@redhat.com>
Date: Thu, 19 Apr 2018 13:44:36 +0000 (+0200)
Subject: qemu: block: Always set discard for storage nodes
X-Git-Tag: v4.4.0-rc1~275
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0e6b60dcac50cc5254c2c54683f89ba50e67ffcd;p=thirdparty%2Flibvirt.git

qemu: block: Always set discard for storage nodes

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@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
---

diff --git a/src/qemu/qemu_block.c b/src/qemu/qemu_block.c
index 775c125467..3424ae5676 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;
     }