block: Add blkdebug hook for copy-on-read

Make it possible to inject errors on writes performed during a
read operation due to copy-on-read semantics.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/block/io.c b/block/io.c
index 94f7470..a5598ed 100644
--- a/block/io.c
+++ b/block/io.c
@@ -983,6 +983,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
         goto err;
     }
 
+    bdrv_debug_event(bs, BLKDBG_COR_WRITE);
     if (drv->bdrv_co_pwrite_zeroes &&
         buffer_is_zero(bounce_buffer, iov.iov_len)) {
         /* FIXME: Should we (perhaps conditionally) be setting