parallels: Use generic infrastructure for BAT writing in parallels_co_check()

BAT is written in the context of conventional operations over the image
inside bdrv_co_flush() when it calls parallels_co_flush_to_os() callback.
Thus we should not modify BAT array directly, but call
parallels_set_bat_entry() helper and bdrv_co_flush() further on. After
that there is no need to manually write BAT and track its modification.

This makes code more generic and allows to split parallels_set_bat_entry()
for independent pieces.

Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Message-Id: <20230424093147.197643-6-alexander.ivanov@virtuozzo.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>

block/parallels.c

@@ -427,9 +427,8 @@ parallels_co_check(BlockDriverState *bs, BdrvCheckResult *res,
 {
     BDRVParallelsState *s = bs->opaque;
     int64_t size, prev_off, high_off;
-    int ret;
+    int ret = 0;
     uint32_t i;
-    bool flush_bat = false;
 
     size = bdrv_getlength(bs->file->bs);
     if (size < 0) {
@@ -467,9 +466,8 @@ parallels_co_check(BlockDriverState *bs, BdrvCheckResult *res,
                     fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
             res->corruptions++;
             if (fix & BDRV_FIX_ERRORS) {
-                s->bat_bitmap[i] = 0;
+                parallels_set_bat_entry(s, i, 0);
                 res->corruptions_fixed++;
-                flush_bat = true;
             }
             prev_off = 0;
             continue;
@@ -486,15 +484,6 @@ parallels_co_check(BlockDriverState *bs, BdrvCheckResult *res,
         prev_off = off;
     }
 
-    ret = 0;
-    if (flush_bat) {
-        ret = bdrv_co_pwrite_sync(bs->file, 0, s->header_size, s->header, 0);
-        if (ret < 0) {
-            res->check_errors++;
-            goto out;
-        }
-    }
-
     if (high_off == 0) {
         res->image_end_offset = s->data_end << BDRV_SECTOR_BITS;
     } else {
@@ -529,6 +518,14 @@ parallels_co_check(BlockDriverState *bs, BdrvCheckResult *res,
 
 out:
     qemu_co_mutex_unlock(&s->lock);
+
+    if (ret == 0) {
+        ret = bdrv_co_flush(bs);
+        if (ret < 0) {
+            res->check_errors++;
+        }
+    }
+
     return ret;
 }