qcow2: Fix L1 write error handling in qcow2_update_snapshot_refcount

It ignored the error code, and at least the 'goto fail' is obvious
nonsense as it creates an endless loop (if the next attempt doesn't
magically succeed) and leaves the in-memory L1 table in big-endian
instead of converting it back.

In error cases, there's no point in writing an updated L1 table, so
skip this part for them.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 47996811372986b4423f0555b67bd74cbc11fcc1..b32738f8d9ce6a8f34d2550759699ac9487a48a3 100644 (file)
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -851,14 +851,16 @@ fail:
     }
 
     /* Update L1 only if it isn't deleted anyway (addend = -1) */
-    if (addend >= 0 && l1_modified) {
-        for(i = 0; i < l1_size; i++)
+    if (ret == 0 && addend >= 0 && l1_modified) {
+        for (i = 0; i < l1_size; i++) {
             cpu_to_be64s(&l1_table[i]);
-        if (bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table,
-                        l1_size2) < 0)
-            goto fail;
-        for(i = 0; i < l1_size; i++)
+        }
+
+        ret = bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table, l1_size2);
+
+        for (i = 0; i < l1_size; i++) {
             be64_to_cpus(&l1_table[i]);
+        }
     }
     if (l1_allocated)
         g_free(l1_table);