diff --git a/block.c b/block.c
index 4a75bb72ead047d56fd6d5b19cfc8f478fe98a2e..25c4fd833336ec934a1cadb7edc15ac2d51713d6 100644
--- a/block.c
+++ b/block.c
@@ -857,7 +857,6 @@ static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
         goto fail_opts;
     }
 
-    bs->guest_block_size = 512;
     bs->request_alignment = 512;
     bs->zero_beyond_eof = true;
     open_flags = bdrv_open_flags(bs, flags);
@@ -2002,7 +2001,6 @@ static void bdrv_move_feature_fields(BlockDriverState *bs_dest,
     /* move some fields that need to stay attached to the device */
 
     /* dev info */
-    bs_dest->guest_block_size   = bs_src->guest_block_size;
     bs_dest->copy_on_read       = bs_src->copy_on_read;
 
     bs_dest->enable_write_cache = bs_src->enable_write_cache;
@@ -3207,11 +3205,6 @@ void bdrv_lock_medium(BlockDriverState *bs, bool locked)
     }
 }
 
-void bdrv_set_guest_block_size(BlockDriverState *bs, int align)
-{
-    bs->guest_block_size = align;
-}
-
 BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const char *name)
 {
     BdrvDirtyBitmap *bm;
diff --git a/block/block-backend.c b/block/block-backend.c
index c7e0f7b6fe0a3d9d640d687eb5d3264886206314..7bc2eb17f4cd0d42d86e9b99cf341896a4c24d2f 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -31,6 +31,9 @@ struct BlockBackend {
     /* TODO change to DeviceState when all users are qdevified */
     const BlockDevOps *dev_ops;
     void *dev_opaque;
+
+    /* the block size for which the guest device expects atomicity */
+    int guest_block_size;
 };
 
 typedef struct BlockBackendAIOCB {
@@ -351,7 +354,7 @@ void blk_detach_dev(BlockBackend *blk, void *dev)
     blk->dev = NULL;
     blk->dev_ops = NULL;
     blk->dev_opaque = NULL;
-    bdrv_set_guest_block_size(blk->bs, 512);
+    blk->guest_block_size = 512;
     blk_unref(blk);
 }
 
@@ -806,7 +809,7 @@ int blk_get_max_transfer_length(BlockBackend *blk)
 
 void blk_set_guest_block_size(BlockBackend *blk, int align)
 {
-    bdrv_set_guest_block_size(blk->bs, align);
+    blk->guest_block_size = align;
 }
 
 void *blk_blockalign(BlockBackend *blk, size_t size)
diff --git a/include/block/block.h b/include/block/block.h
index 8340a6748e045c0994c38dd84026382a23cb1b8b..8a6f001d5c5f2b138e7f142f2779ffa50db339f0 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -466,7 +466,6 @@ void bdrv_img_create(const char *filename, const char *fmt,
 size_t bdrv_min_mem_align(BlockDriverState *bs);
 /* Returns optimal alignment in bytes for bounce buffer */
 size_t bdrv_opt_mem_align(BlockDriverState *bs);
-void bdrv_set_guest_block_size(BlockDriverState *bs, int align);
 void *qemu_blockalign(BlockDriverState *bs, size_t size);
 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 0ff6f2fe23b52f65be1a918caf9c660b4d1719b0..6860787eb641029e0e8bbcd24f4ab1f15096a0b0 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -411,9 +411,6 @@ struct BlockDriverState {
     /* Alignment requirement for offset/length of I/O requests */
     unsigned int request_alignment;
 
-    /* the block size for which the guest device expects atomicity */
-    int guest_block_size;
-
     /* do we need to tell the quest if we have a volatile write cache? */
     int enable_write_cache;