[PATCH 13/14] block/qcow2: qcow2_do_open: deal with errp

[Vladimir Sementsov-Ogievskiy]

1. Drop extra error propagation

2. Set errp always on failure. Generic bdrv_open_driver supports driver
functions which can return negative value and forget to set errp.
That's a strange thing.. Let's improve qcow2_do_open to not behave this
way. This allows to simplify code in qcow2_co_invalidate_cache().

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/qcow2.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index 31dd28d19e..cc4e7dd461 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1292,6 +1292,7 @@ static int validate_compression_type(BDRVQcow2State *s, 
Error **errp)
 static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
                                       int flags, Error **errp)
 {
+    ERRP_GUARD();
     BDRVQcow2State *s = bs->opaque;
     unsigned int len, i;
     int ret = 0;
@@ -1426,6 +1427,8 @@ static int coroutine_fn qcow2_do_open(BlockDriverState 
*bs, QDict *options,
         report_unsupported_feature(errp, feature_table,
                                    s->incompatible_features &
                                    ~QCOW2_INCOMPAT_MASK);
+        error_setg(errp,
+                   "qcow2 header contains unknown incompatible_feature bits");
         ret = -ENOTSUP;
         g_free(feature_table);
         goto fail;
@@ -2709,11 +2712,11 @@ static void qcow2_close(BlockDriverState *bs)
 static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs,
                                                    Error **errp)
 {
+    ERRP_GUARD();
     BDRVQcow2State *s = bs->opaque;
     int flags = s->flags;
     QCryptoBlock *crypto = NULL;
     QDict *options;
-    Error *local_err = NULL;
     int ret;
 
     /*
@@ -2731,16 +2734,11 @@ static void coroutine_fn 
qcow2_co_invalidate_cache(BlockDriverState *bs,
 
     flags &= ~BDRV_O_INACTIVE;
     qemu_co_mutex_lock(&s->lock);
-    ret = qcow2_do_open(bs, options, flags, &local_err);
+    ret = qcow2_do_open(bs, options, flags, errp);
     qemu_co_mutex_unlock(&s->lock);
     qobject_unref(options);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "Could not reopen qcow2 layer: ");
-        bs->drv = NULL;
-        return;
-    } else if (ret < 0) {
-        error_setg_errno(errp, -ret, "Could not reopen qcow2 layer");
+    if (ret < 0) {
+        error_prepend(errp, "Could not reopen qcow2 layer: ");
         bs->drv = NULL;
         return;
     }
-- 
2.21.3