block: Don't emulate natively supported pwritev flags

Drivers that implement .bdrv_co_pwritev() get the flags passed as an
argument to said function, but we also unconditionally emulate the flags
anyway. We shouldn't do that.

Fix this by clearing all flags that the driver supports natively after
it returns from .bdrv_co_pwritev().

Fixes: 4df863f3 ('block: Make supported_write_flags a per-bds property')
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/block/io.c b/block/io.c
index 9dc265b..fb99a71 100644
--- a/block/io.c
+++ b/block/io.c
@@ -816,7 +816,9 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
     int ret;
 
     if (drv->bdrv_co_pwritev) {
-        ret = drv->bdrv_co_pwritev(bs, offset, bytes, qiov, flags);
+        ret = drv->bdrv_co_pwritev(bs, offset, bytes, qiov,
+                                   flags & bs->supported_write_flags);
+        flags &= ~bs->supported_write_flags;
         goto emulate_flags;
     }