block/dirty-bitmap: add readonly field to BdrvDirtyBitmap

It will be needed in following commits for persistent bitmaps.
If bitmap is loaded from read-only storage (and we can't mark it
"in use" in this storage) corresponding BdrvDirtyBitmap should be
read-only.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20170628120530.31251-11-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/blockdev.c b/blockdev.c
index 92c59910fc..edeb36bd3b 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2033,6 +2033,9 @@ static void block_dirty_bitmap_clear_prepare(BlkActionState *common,
     } else if (!bdrv_dirty_bitmap_enabled(state->bitmap)) {
         error_setg(errp, "Cannot clear a disabled bitmap");
         return;
+    } else if (bdrv_dirty_bitmap_readonly(state->bitmap)) {
+        error_setg(errp, "Cannot clear a readonly bitmap");
+        return;
     }
 
     bdrv_clear_dirty_bitmap(state->bitmap, &state->backup);
@@ -2779,6 +2782,9 @@ void qmp_block_dirty_bitmap_clear(const char *node, const char *name,
                    "Bitmap '%s' is currently disabled and cannot be cleared",
                    name);
         return;
+    } else if (bdrv_dirty_bitmap_readonly(bitmap)) {
+        error_setg(errp, "Bitmap '%s' is readonly and cannot be cleared", name);
+        return;
     }
 
     bdrv_clear_dirty_bitmap(bitmap, NULL);