Right now, all users of bdrv_make_empty() call the BlockDriver method
directly. That is not only bad style, it is also wrong, unless the
caller has a BdrvChild with a WRITE permission.
Introduce bdrv_make_empty() that verifies that it does.
Signed-off-by: Max Reitz <mre...@redhat.com>
---
include/block/block.h | 1 +
block.c | 23 +++++++++++++++++++++++
2 files changed, 24 insertions(+)
diff --git a/include/block/block.h b/include/block/block.h
index b05995fe9c..d947fb4080 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -351,6 +351,7 @@ BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts
*opts,
void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
int bdrv_commit(BlockDriverState *bs);
+int bdrv_make_empty(BdrvChild *c, Error **errp);
int bdrv_change_backing_file(BlockDriverState *bs,
const char *backing_file, const char *backing_fmt);
void bdrv_register(BlockDriver *bdrv);
diff --git a/block.c b/block.c
index 2e3905c99e..b0d5b98617 100644
--- a/block.c
+++ b/block.c
@@ -6791,3 +6791,26 @@ void bdrv_del_child(BlockDriverState *parent_bs,
BdrvChild *child, Error **errp)
parent_bs->drv->bdrv_del_child(parent_bs, child, errp);
}
+
+int bdrv_make_empty(BdrvChild *c, Error **errp)
+{
+ BlockDriver *drv = c->bs->drv;
+ int ret;
+
+ assert(c->perm & BLK_PERM_WRITE);
+
+ if (!drv->bdrv_make_empty) {
+ error_setg(errp, "%s does not support emptying nodes",
+ drv->format_name);
+ return -ENOTSUP;
+ }
+
+ ret = drv->bdrv_make_empty(c->bs);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Failed to empty %s",
+ c->bs->filename);
+ return ret;
+ }
+
+ return 0;
+}
--
2.25.4
