From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Only qcow2 driver supports vmstate.
In qcow2 these requests go through .bdrv_co_p{read,write}v_part
handlers.

So, let's do our basic check for the request on vmstate generic
handlers.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210903102807.27127-2-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/io.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/block/io.c b/block/io.c
index 99ee182ca449..58602f84dbf0 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2810,7 +2810,12 @@ bdrv_co_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
 {
     BlockDriver *drv = bs->drv;
     BlockDriverState *child_bs = bdrv_primary_bs(bs);
-    int ret = -ENOTSUP;
+    int ret;
+
+    ret = bdrv_check_qiov_request(pos, qiov->size, qiov, 0, NULL);
+    if (ret < 0) {
+        return ret;
+    }

     if (!drv) {
         return -ENOMEDIUM;
@@ -2822,6 +2827,8 @@ bdrv_co_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
         ret = drv->bdrv_load_vmstate(bs, qiov, pos);
     } else if (child_bs) {
         ret = bdrv_co_readv_vmstate(child_bs, qiov, pos);
+    } else {
+        ret = -ENOTSUP;
     }

     bdrv_dec_in_flight(bs);
@@ -2834,7 +2841,12 @@ bdrv_co_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
 {
     BlockDriver *drv = bs->drv;
     BlockDriverState *child_bs = bdrv_primary_bs(bs);
-    int ret = -ENOTSUP;
+    int ret;
+
+    ret = bdrv_check_qiov_request(pos, qiov->size, qiov, 0, NULL);
+    if (ret < 0) {
+        return ret;
+    }

     if (!drv) {
         return -ENOMEDIUM;
@@ -2846,6 +2858,8 @@ bdrv_co_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
         ret = drv->bdrv_save_vmstate(bs, qiov, pos);
     } else if (child_bs) {
         ret = bdrv_co_writev_vmstate(child_bs, qiov, pos);
+    } else {
+        ret = -ENOTSUP;
     }

     bdrv_dec_in_flight(bs);
-- 
2.31.1