[PATCH v2 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 | 88 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 61 insertions(+), 27 deletions(-)

diff --git a/block/parallels.c b/block/parallels.c
index ed2cf27abc..da1e75096c 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -475,21 +475,53 @@ static int parallels_check_outside_image(BlockDriverState *bs,
     return 0;
 }
 
+static int64_t parallels_get_leak_size(BlockDriverState *bs,
+                                       BdrvCheckResult *res)
+{
+    int64_t size;
+    size = bdrv_getlength(bs->file->bs);
+    /*
+     * Before any usage of this function out-of-image corruption has been
+     * fixed. If the function returns a negative value, it means an error.
+     */
+    return (size < 0) ? size : (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 parallels_check_leak(BlockDriverState *bs,
                                 BdrvCheckResult *res,
                                 BdrvCheckMode fix)
 {
     BDRVParallelsState *s = bs->opaque;
-    int64_t size, off, high_off, count;
+    int64_t off, high_off, count, leak_size;
     uint32_t i;
     int ret;
 
-    size = bdrv_getlength(bs->file->bs);
-    if (size < 0) {
-        res->check_errors++;
-        return size;
-    }
-
     high_off = 0;
     for (i = 0; i < s->bat_size; i++) {
         off = bat2sect(s, i) << BDRV_SECTOR_BITS;
@@ -499,30 +531,32 @@ static int parallels_check_leak(BlockDriverState *bs,
     }
 
     res->image_end_offset = high_off + s->cluster_size;
-    if (size > res->image_end_offset) {
-        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;
 
-            /*
-             * 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;
+    leak_size = parallels_get_leak_size(bs, res);
+    if (leak_size < 0) {
+        res->check_errors++;
+        return leak_size;
+    }
+    if (leak_size == 0) {
+        return 0;
+    }
+
+    if (fix & BDRV_FIX_LEAKS) {
+        ret = parallels_fix_leak(bs, res);
+        if (ret < 0) {
+            return ret;
         }
     }
 
+    count = DIV_ROUND_UP(leak_size, s->cluster_size);
+    fprintf(stderr, "%s space leaked at the end of the image %" PRId64 "\n",
+            fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR", leak_size);
+
+    res->leaks += count;
+    if (fix & BDRV_FIX_LEAKS) {
+        res->leaks_fixed += count;
+    }
+
     return 0;
 }
 
-- 
2.34.1