block: add .bdrv_co_write_zeroes() interface

[qemu.git] / block_int.h

diff --git a/block_int.h b/block_int.h
index 7be2988ca7098f3ca16bf24ff69dfa957690fb7a..7946cf66a1d6375e83bc7ad37e08406c561a71b8 100644 (file)
--- a/block_int.h
+++ b/block_int.h
@@ -131,6 +131,14 @@ struct BlockDriver {
         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
     int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
+    /*
+     * Efficiently zero a region of the disk image.  Typically an image format
+     * would use a compact metadata representation to implement this.  This
+     * function pointer may be NULL and .bdrv_co_writev() will be called
+     * instead.
+     */
+    int coroutine_fn (*bdrv_co_write_zeroes)(BlockDriverState *bs,
+        int64_t sector_num, int nb_sectors);
     int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs,
         int64_t sector_num, int nb_sectors);
     int coroutine_fn (*bdrv_co_is_allocated)(BlockDriverState *bs,