[Qemu-devel] [PATCH v3 21/21] qcow2: Return useful error code in refcount_init()

[Kevin Wolf <kwolf@redhat.com>]

From: Max Reitz <mreitz@redhat.com>

If bdrv_pread() returns an error, it is very unlikely that it was
ENOMEM. In this case, the return value should be passed along; as
bdrv_pread() will always either return the number of bytes read or a
negative value (the error code), the condition for checking whether
bdrv_pread() failed can be simplified (and clarified) as well.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/qcow2-refcount.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index a234c7a..6b367c8 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -49,19 +49,21 @@ int qcow2_refcount_init(BlockDriverState *bs)
 
     if (s->refcount_table_size > 0) {
         if (s->refcount_table == NULL) {
+            ret = -ENOMEM;
             goto fail;
         }
         BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD);
         ret = bdrv_pread(bs->file, s->refcount_table_offset,
                          s->refcount_table, refcount_table_size2);
-        if (ret != refcount_table_size2)
+        if (ret < 0) {
             goto fail;
+        }
         for(i = 0; i < s->refcount_table_size; i++)
             be64_to_cpus(&s->refcount_table[i]);
     }
     return 0;
  fail:
-    return -ENOMEM;
+    return ret;
 }
 
 void qcow2_refcount_close(BlockDriverState *bs)
-- 
1.8.3.1