block: Add PreallocMode to BD.bdrv_truncate()

Add a PreallocMode parameter to the bdrv_truncate() function implemented
by each block driver. Currently, we always pass PREALLOC_MODE_OFF and no
driver accepts anything else.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/block/gluster.c b/block/gluster.c
index addceed6eb..bfa4df1c81 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -1096,11 +1096,17 @@ static coroutine_fn int qemu_gluster_co_rw(BlockDriverState *bs,
 }
 
 static int qemu_gluster_truncate(BlockDriverState *bs, int64_t offset,
-                                 Error **errp)
+                                 PreallocMode prealloc, Error **errp)
 {
     int ret;
     BDRVGlusterState *s = bs->opaque;
 
+    if (prealloc != PREALLOC_MODE_OFF) {
+        error_setg(errp, "Unsupported preallocation mode '%s'",
+                   PreallocMode_lookup[prealloc]);
+        return -ENOTSUP;
+    }
+
     ret = glfs_ftruncate(s->fd, offset);
     if (ret < 0) {
         ret = -errno;