[Qemu-devel] [RFC PATCH v3 2/6] block: add BlockDriver.bdrv_preallocate.

[Hu Tao <hutao@cn.fujitsu.com>]

This field is used to preallocate disk space for block device.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
 block.c                   | 13 +++++++++++++
 include/block/block.h     |  1 +
 include/block/block_int.h |  3 +++
 3 files changed, 17 insertions(+)

diff --git a/block.c b/block.c
index 64e7d22..b901587 100644
--- a/block.c
+++ b/block.c
@@ -3216,6 +3216,19 @@ bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
     return false;
 }
 
+int bdrv_preallocate(BlockDriverState *bs, int64_t offset, int64_t length)
+{
+    if (bs->backing_hd) {
+        return -ENOTSUP;
+    }
+
+    if (bs->drv->bdrv_preallocate) {
+        return bs->drv->bdrv_preallocate(bs, offset, length);
+    }
+
+    return -ENOTSUP;
+}
+
 typedef struct BdrvCoGetBlockStatusData {
     BlockDriverState *bs;
     BlockDriverState *base;
diff --git a/include/block/block.h b/include/block/block.h
index 3732f25..bc1f277 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -349,6 +349,7 @@ int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
 int bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
 int bdrv_has_zero_init_1(BlockDriverState *bs);
 int bdrv_has_zero_init(BlockDriverState *bs);
+int bdrv_preallocate(BlockDriverState *bs, int64_t offset, int64_t length);
 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
 int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 8b132d7..5bb1005 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -232,6 +232,9 @@ struct BlockDriver {
      */
     int (*bdrv_has_zero_init)(BlockDriverState *bs);
 
+    int (*bdrv_preallocate)(BlockDriverState *bs, int64_t offset,
+                            int64_t length);
+
     QLIST_ENTRY(BlockDriver) list;
 };
 
-- 
1.7.11.7