[PATCH v4 18/24] nbd/client: Plumb errp through nbd_receive_replies

[Eric Blake <eblake@redhat.com>]

Instead of ignoring the low-level error just to refabricate our own
message to pass to the caller, we can just plump the caller's errp
down to the low level.

Signed-off-by: Eric Blake <eblake@redhat.com>
---

v4: new patch [Vladimir]
---
 block/nbd.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/block/nbd.c b/block/nbd.c
index 57123c17f94..c17ce935f17 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -417,7 +417,8 @@ static void coroutine_fn GRAPH_RDLOCK nbd_reconnect_attempt(BDRVNBDState *s)
     reconnect_delay_timer_del(s);
 }

-static coroutine_fn int nbd_receive_replies(BDRVNBDState *s, uint64_t cookie)
+static coroutine_fn int nbd_receive_replies(BDRVNBDState *s, uint64_t cookie,
+                                            Error **errp)
 {
     int ret;
     uint64_t ind = COOKIE_TO_INDEX(cookie), ind2;
@@ -458,9 +459,12 @@ static coroutine_fn int nbd_receive_replies(BDRVNBDState *s, uint64_t cookie)

         /* We are under mutex and cookie is 0. We have to do the dirty work. */
         assert(s->reply.cookie == 0);
-        ret = nbd_receive_reply(s->bs, s->ioc, &s->reply, NULL);
-        if (ret <= 0) {
-            ret = ret ? ret : -EIO;
+        ret = nbd_receive_reply(s->bs, s->ioc, &s->reply, errp);
+        if (ret == 0) {
+            ret = -EIO;
+            error_setg(errp, "server dropped connection");
+        }
+        if (ret < 0) {
             nbd_channel_error(s, ret);
             return ret;
         }
@@ -843,9 +847,9 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
     }
     *request_ret = 0;

-    ret = nbd_receive_replies(s, cookie);
+    ret = nbd_receive_replies(s, cookie, errp);
     if (ret < 0) {
-        error_setg(errp, "Connection closed");
+        error_prepend(errp, "Connection closed: ");
         return -EIO;
     }
     assert(s->ioc);
-- 
2.40.1