diff --git a/block.c b/block.c
index 998df1b54b8c7418052e58e64fe79523cfdf9376..ee9edfce2c816e3487b69c3777337caceea85cd0 100644
--- a/block.c
+++ b/block.c
@@ -2774,6 +2774,17 @@ int64_t bdrv_get_dirty_count(BlockDriverState *bs)
     return bs->dirty_count;
 }
 
+void bdrv_set_in_use(BlockDriverState *bs, int in_use)
+{
+    assert(bs->in_use != in_use);
+    bs->in_use = in_use;
+}
+
+int bdrv_in_use(BlockDriverState *bs)
+{
+    return bs->in_use;
+}
+
 int bdrv_img_create(const char *filename, const char *fmt,
                     const char *base_filename, const char *base_fmt,
                     char *options, uint64_t img_size, int flags)
diff --git a/block.h b/block.h
index 239f729580520ceb5fc5e3d0e79c7e3129f56817..19f4768873c218517fad2df2ba13d400b369f527 100644
--- a/block.h
+++ b/block.h
@@ -241,6 +241,8 @@ void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector,
                       int nr_sectors);
 int64_t bdrv_get_dirty_count(BlockDriverState *bs);
 
+void bdrv_set_in_use(BlockDriverState *bs, int in_use);
+int bdrv_in_use(BlockDriverState *bs);
 
 typedef enum {
     BLKDBG_L1_UPDATE,
diff --git a/block_int.h b/block_int.h
index 6ebdc3eea27c51f5e8fa76be1360169b4464fe14..545ad11ff35c75d8a503e91dcbd385869f61a5fa 100644
--- a/block_int.h
+++ b/block_int.h
@@ -199,6 +199,7 @@ struct BlockDriverState {
     char device_name[32];
     unsigned long *dirty_bitmap;
     int64_t dirty_count;
+    int in_use; /* users other than guest access, eg. block migration */
     QTAILQ_ENTRY(BlockDriverState) list;
     void *private;
 };