block: Add PreallocMode to bdrv_truncate()

For block drivers that just pass a truncate request to the underlying
protocol, we can now pass the preallocation mode instead of aborting if
it is not PREALLOC_MODE_OFF.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-3-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/block.c b/block.c
index 37e7b3d30a..d24ae85868 100644
--- a/block.c
+++ b/block.c
@@ -3411,7 +3411,8 @@ exit:
 /**
  * Truncate file to 'offset' bytes (needed only for file protocols)
  */
-int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp)
+int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
+                  Error **errp)
 {
     BlockDriverState *bs = child->bs;
     BlockDriver *drv = bs->drv;
@@ -3434,7 +3435,7 @@ int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp)
 
     assert(!(bs->open_flags & BDRV_O_INACTIVE));
 
-    ret = drv->bdrv_truncate(bs, offset, PREALLOC_MODE_OFF, errp);
+    ret = drv->bdrv_truncate(bs, offset, prealloc, errp);
     if (ret == 0) {
         ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
         bdrv_dirty_bitmap_truncate(bs);