Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2019-01-05' into staging

nbd patches for 2019-01-05

Error and trace improvements in NBD code, such as less noise for
common disconnect scenarios.

- Vladimir Sementsov-Ogievskiy: 0/3 nbd-client: drop extra error noise
- Eric Blake: portions of 0/22 nbd: add qemu-nbd --list

# gpg: Signature made Sat 05 Jan 2019 13:58:54 GMT
# gpg:                using RSA key A7A16B4A2527436A
# 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-2019-01-05:
  nbd/client: Drop pointless buf variable
  qemu-nbd: Fail earlier for -c/-d on non-linux
  nbd/client: More consistent error messages
  nbd: Document timeline of various features
  qemu-nbd: Use program name in error messages
  block/nbd-client: use traces instead of noisy error_report_err
  nbd/client: Trace all server option error messages
  nbd: publish _lookup functions

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

1 files changed, 20 insertions, 2 deletions

diff --git a/qemu-nbd.c b/qemu-nbd.c
index ca7109652e..2807e13239 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -43,6 +43,12 @@
 #include "trace/control.h"
 #include "qemu-version.h"
 
+#ifdef __linux__
+#define HAVE_NBD_DEVICE 1
+#else
+#define HAVE_NBD_DEVICE 0
+#endif
+
 #define SOCKET_PATH                "/var/lock/qemu-nbd-%s"
 #define QEMU_NBD_OPT_CACHE         256
 #define QEMU_NBD_OPT_AIO           257
@@ -98,11 +104,11 @@ static void usage(const char *name)
 "                            specify tracing options\n"
 "  --fork                    fork off the server process and exit the parent\n"
 "                            once the server is running\n"
-#ifdef __linux__
+#if HAVE_NBD_DEVICE
+"\n"
 "Kernel NBD client support:\n"
 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
 "  -d, --disconnect          disconnect the specified device\n"
-"\n"
 #endif
 "\n"
 "Block device options:\n"
@@ -236,6 +242,7 @@ static void termsig_handler(int signum)
 }
 
 
+#if HAVE_NBD_DEVICE
 static void *show_parts(void *arg)
 {
     char *device = arg;
@@ -321,6 +328,7 @@ out:
     kill(getpid(), SIGTERM);
     return (void *) EXIT_FAILURE;
 }
+#endif /* HAVE_NBD_DEVICE */
 
 static int nbd_can_accept(void)
 {
@@ -571,6 +579,7 @@ int main(int argc, char **argv)
 #endif
 
     module_call_init(MODULE_INIT_TRACE);
+    error_set_progname(argv[0]);
     qcrypto_init(&error_fatal);
 
     module_call_init(MODULE_INIT_QOM);
@@ -813,6 +822,12 @@ int main(int argc, char **argv)
         }
     }
 
+#if !HAVE_NBD_DEVICE
+    if (disconnect || device) {
+        error_report("Kernel /dev/nbdN support not available");
+        exit(EXIT_FAILURE);
+    }
+#else /* HAVE_NBD_DEVICE */
     if (disconnect) {
         int nbdfd = open(argv[optind], O_RDWR);
         if (nbdfd < 0) {
@@ -828,6 +843,7 @@ int main(int argc, char **argv)
 
         return 0;
     }
+#endif
 
     if ((device && !verbose) || fork_process) {
         int stderr_fd[2];
@@ -1005,6 +1021,7 @@ int main(int argc, char **argv)
     nbd_export_set_description(exp, export_description);
 
     if (device) {
+#if HAVE_NBD_DEVICE
         int ret;
 
         ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
@@ -1012,6 +1029,7 @@ int main(int argc, char **argv)
             error_report("Failed to create client thread: %s", strerror(ret));
             exit(EXIT_FAILURE);
         }
+#endif
     } else {
         /* Shut up GCC warnings.  */
         memset(&client_thread, 0, sizeof(client_thread));