Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2017-08-30' into staging

nbd patches for 2017-08-30

- Kashyap Chamarthy: qemu-iotests: Extend non-shared storage migration test (194)
- Stefan Hajnaczi: 0/3 nbd-client: enter read_reply_co during init to avoid crash
- Vladimir Sementsov-Ogievskiy: portions of 0/17 nbd client refactoring and fixing

# gpg: Signature made Wed 30 Aug 2017 19:03:46 BST
# gpg:                using RSA key 0xA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2017-08-30:
  block/nbd-client: refactor request send/receive
  block/nbd-client: rename nbd_recv_coroutines_enter_all
  block/nbd-client: get rid of ssize_t
  nbd/client: fix nbd_send_request to return int
  nbd/client: refactor nbd_receive_reply
  nbd/client: refactor nbd_read_eof
  nbd/client: fix nbd_opt_go
  qemu-iotests: test NBD over UNIX domain sockets in 083
  qemu-iotests: improve nbd-fault-injector.py startup protocol
  nbd-client: avoid read_reply_co entry if send failed
  qemu-iotests: Extend non-shared storage migration test (194)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 34 insertions, 20 deletions

diff --git a/nbd/client.c b/nbd/client.c
index 0a17de80b5..68a0bc1ffc 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -399,12 +399,10 @@ static int nbd_opt_go(QIOChannel *ioc, const char *wantname,
                phase, but make sure it sent flags */
             if (len) {
                 error_setg(errp, "server sent invalid NBD_REP_ACK");
-                nbd_send_opt_abort(ioc);
                 return -1;
             }
             if (!info->flags) {
                 error_setg(errp, "broken server omitted NBD_INFO_EXPORT");
-                nbd_send_opt_abort(ioc);
                 return -1;
             }
             trace_nbd_opt_go_success();
@@ -898,7 +896,7 @@ int nbd_disconnect(int fd)
 }
 #endif
 
-ssize_t nbd_send_request(QIOChannel *ioc, NBDRequest *request)
+int nbd_send_request(QIOChannel *ioc, NBDRequest *request)
 {
     uint8_t buf[NBD_REQUEST_SIZE];
 
@@ -916,22 +914,22 @@ ssize_t nbd_send_request(QIOChannel *ioc, NBDRequest *request)
     return nbd_write(ioc, buf, sizeof(buf), NULL);
 }
 
-ssize_t nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp)
+/* nbd_receive_reply
+ * Returns 1 on success
+ *         0 on eof, when no data was read (errp is not set)
+ *         negative errno on failure (errp is set)
+ */
+int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp)
 {
     uint8_t buf[NBD_REPLY_SIZE];
     uint32_t magic;
-    ssize_t ret;
+    int ret;
 
     ret = nbd_read_eof(ioc, buf, sizeof(buf), errp);
     if (ret <= 0) {
         return ret;
     }
 
-    if (ret != sizeof(buf)) {
-        error_setg(errp, "read failed");
-        return -EINVAL;
-    }
-
     /* Reply
        [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
        [ 4 ..  7]    error   (0 == no error)
@@ -955,6 +953,7 @@ ssize_t nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp)
         error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);
         return -EINVAL;
     }
-    return sizeof(buf);
+
+    return 1;
 }
 
diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h
index 396ddb4d3e..03549e3f39 100644
--- a/nbd/nbd-internal.h
+++ b/nbd/nbd-internal.h
@@ -77,21 +77,36 @@
 #define NBD_ESHUTDOWN  108
 
 /* nbd_read_eof
- * Tries to read @size bytes from @ioc. Returns number of bytes actually read.
- * May return a value >= 0 and < size only on EOF, i.e. when iteratively called
- * qio_channel_readv() returns 0. So, there is no need to call nbd_read_eof
- * iteratively.
+ * Tries to read @size bytes from @ioc.
+ * Returns 1 on success
+ *         0 on eof, when no data was read (errp is not set)
+ *         negative errno on failure (errp is set)
  */
-static inline ssize_t nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
-                                   Error **errp)
+static inline int nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
+                               Error **errp)
 {
     struct iovec iov = { .iov_base = buffer, .iov_len = size };
+    ssize_t ret;
+
     /* Sockets are kept in blocking mode in the negotiation phase.  After
      * that, a non-readable socket simply means that another thread stole
      * our request/reply.  Synchronization is done with recv_coroutine, so
      * that this is coroutine-safe.
      */
-    return nbd_rwv(ioc, &iov, 1, size, true, errp);
+
+    assert(size);
+
+    ret = nbd_rwv(ioc, &iov, 1, size, true, errp);
+    if (ret <= 0) {
+        return ret;
+    }
+
+    if (ret != size) {
+        error_setg(errp, "End of file");
+        return -EINVAL;
+    }
+
+    return 1;
 }
 
 /* nbd_read
@@ -100,9 +115,9 @@ static inline ssize_t nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
                            Error **errp)
 {
-    ssize_t ret = nbd_read_eof(ioc, buffer, size, errp);
+    int ret = nbd_read_eof(ioc, buffer, size, errp);
 
-    if (ret >= 0 && ret != size) {
+    if (ret == 0) {
         ret = -EINVAL;
         error_setg(errp, "End of file");
     }