[PATCH v4 2/5] parallels: Split image leak handling to separate check and fix helpers

[Alexander Ivanov <alexander.ivanov@virtuozzo.com>]

We need to fix leak after deduplication in the next patch. Move leak
fixing to a separate helper parallels_fix_leak() and add
parallels_get_leak_size() helper wich used in parallels_fix_leak() and
parallels_check_leak().

Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
---
 block/parallels.c | 86 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 61 insertions(+), 25 deletions(-)

diff --git a/block/parallels.c b/block/parallels.c
index 60033c1204..ec89ed894b 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -482,43 +482,79 @@ parallels_check_outside_image(BlockDriverState *bs, BdrvCheckResult *res,
     return 0;
 }
 
+static int64_t parallels_get_leak_size(BlockDriverState *bs,
+                                       BdrvCheckResult *res)
+{
+    int64_t size;
+
+    size = bdrv_getlength(bs->file->bs);
+    if (size < 0) {
+        return size;
+    }
+
+    /*
+     * Before any usage of this function, image_end_offset has to be set to the
+     * the highest offset in the BAT, excluding out-of-image offsets.
+     */
+    assert(size >= res->image_end_offset);
+
+    return size - res->image_end_offset;
+}
+
+static int parallels_fix_leak(BlockDriverState *bs,
+                              BdrvCheckResult *res)
+{
+    Error *local_err = NULL;
+    int64_t size;
+    int ret;
+
+    size = parallels_get_leak_size(bs, res);
+    if (size <= 0) {
+        return size;
+    }
+
+    /*
+     * In order to really repair the image, we must shrink it.
+     * That means we have to pass exact=true.
+     */
+    ret = bdrv_co_truncate(bs->file, res->image_end_offset, true,
+                           PREALLOC_MODE_OFF, 0, &local_err);
+    if (ret < 0) {
+        error_report_err(local_err);
+        return ret;
+    }
+
+    return 0;
+}
+
 static int coroutine_fn GRAPH_RDLOCK
 parallels_check_leak(BlockDriverState *bs, BdrvCheckResult *res,
                      BdrvCheckMode fix)
 {
     BDRVParallelsState *s = bs->opaque;
-    int64_t size;
+    int64_t count, leak_size;
     int ret;
 
-    size = bdrv_getlength(bs->file->bs);
-    if (size < 0) {
+    leak_size = parallels_get_leak_size(bs, res);
+    if (leak_size < 0) {
         res->check_errors++;
-        return size;
+        return leak_size;
+    }
+    if (leak_size == 0) {
+        return 0;
     }
 
-    if (size > res->image_end_offset) {
-        int64_t count;
-        count = DIV_ROUND_UP(size - res->image_end_offset, s->cluster_size);
-        fprintf(stderr, "%s space leaked at the end of the image %" PRId64 "\n",
-                fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR",
-                size - res->image_end_offset);
-        res->leaks += count;
-        if (fix & BDRV_FIX_LEAKS) {
-            Error *local_err = NULL;
+    count = DIV_ROUND_UP(leak_size, s->cluster_size);
+    res->leaks += count;
+    fprintf(stderr, "%s space leaked at the end of the image %" PRId64 "\n",
+            fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR", leak_size);
 
-            /*
-             * In order to really repair the image, we must shrink it.
-             * That means we have to pass exact=true.
-             */
-            ret = bdrv_co_truncate(bs->file, res->image_end_offset, true,
-                                   PREALLOC_MODE_OFF, 0, &local_err);
-            if (ret < 0) {
-                error_report_err(local_err);
-                res->check_errors++;
-                return ret;
-            }
-            res->leaks_fixed += count;
+    if (fix & BDRV_FIX_LEAKS) {
+        ret = parallels_fix_leak(bs, res);
+        if (ret < 0) {
+            return ret;
         }
+        res->leaks_fixed += count;
     }
 
     return 0;
-- 
2.34.1