[Qemu-devel] [PATCH v5 18/38] block: Make some BB functions fall back to BBRS

[Max Reitz <mreitz@redhat.com>]

If there is no BDS tree attached to a BlockBackend, functions that can
do so should fall back to the BlockBackendRootState structure (which are
blk_is_read_only() and blk_get_flags(), because the read-only status and
the "open flags" are part of the BBRS).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/block-backend.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index 9590be5..417374f 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -852,7 +852,11 @@ void blk_error_action(BlockBackend *blk, BlockErrorAction action,
 
 int blk_is_read_only(BlockBackend *blk)
 {
-    return bdrv_is_read_only(blk->bs);
+    if (blk->bs) {
+        return bdrv_is_read_only(blk->bs);
+    } else {
+        return blk->root_state.read_only;
+    }
 }
 
 int blk_is_sg(BlockBackend *blk)
@@ -897,7 +901,11 @@ void blk_eject(BlockBackend *blk, bool eject_flag)
 
 int blk_get_flags(BlockBackend *blk)
 {
-    return bdrv_get_flags(blk->bs);
+    if (blk->bs) {
+        return bdrv_get_flags(blk->bs);
+    } else {
+        return blk->root_state.open_flags;
+    }
 }
 
 int blk_get_max_transfer_length(BlockBackend *blk)
-- 
2.5.2