[Qemu-devel] [PATCH 2/2] qcow2: Fix L1 write error handling in qcow2_update_snapshot_refcount

[Kevin Wolf <kwolf@redhat.com>]

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>
---
 block/qcow2-refcount.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 4799681..b32738f 100644
--- 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);
-- 
1.8.1.4