Am 19.04.2018 um 17:25 hat Peter Krempa geschrieben:
According to my research it seems that qemu always sets discard for the storage nodes. Replicate this in our generator. --- 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 44662a4603..0357d93384 100644 --- a/src/qemu/qemu_block.c +++ b/src/qemu/qemu_block.c @@ -1155,7 +1155,10 @@ 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; }
Looks correct to me. The QEMU default means that discard requests made by the guest are ignored (already at the format level), but discard requests made by a format driver to the protocol layer are honoured (e.g. qcow2 discarding data when an internal snapshot is deleted). Kevin