[Qemu-block] [PATCH v5 10/42] block: Use CAF in bdrv_is_encrypted()

[Max Reitz]

bdrv_is_encrypted() should not only check the BDS's backing child, but
any filtered child: If a filter's child is encrypted, the filter node
itself naturally is encrypted, too.  Furthermore, we need to recurse
down the chain.

(CAF means child access function.)

Signed-off-by: Max Reitz <mre...@redhat.com>
---
 block.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/block.c b/block.c
index 45882a3470..567a0f82c8 100644
--- a/block.c
+++ b/block.c
@@ -4574,10 +4574,14 @@ bool bdrv_is_sg(BlockDriverState *bs)
 
 bool bdrv_is_encrypted(BlockDriverState *bs)
 {
-    if (bs->backing && bs->backing->bs->encrypted) {
+    BlockDriverState *filtered = bdrv_filtered_bs(bs);
+    if (bs->encrypted) {
         return true;
     }
-    return bs->encrypted;
+    if (filtered && bdrv_is_encrypted(filtered)) {
+        return true;
+    }
+    return false;
 }
 
 const char *bdrv_get_format_name(BlockDriverState *bs)
-- 
2.21.0