[PULL 0/6] NBD patches for 2020-09-02

[PULL 0/6] NBD patches for 2020-09-02

[Eric Blake]

The following changes since commit ed215cec0fcaeaece064b0fdf37fe3bceb06d76c:

  Merge remote-tracking branch 'remotes/ehabkost/tags/machine-next-pull-request' into staging (2020-09-02 15:26:38 +0100)

are available in the Git repository at:

  https://repo.or.cz/qemu/ericb.git tags/pull-nbd-2020-09-02

for you to fetch changes up to eb705985f43d631438a318f1146eac61ae10d273:

  nbd: disable signals and forking on Windows builds (2020-09-02 16:48:21 -0500)

----------------------------------------------------------------
nbd patches for 2020-09-02

- fix a few iotests affected by earlier nbd changes
- avoid blocking qemu by nbd client in connect()
- build qemu-nbd for mingw

----------------------------------------------------------------
Daniel P. Berrangé (3):
      block: add missing socket_init() calls to tools
      nbd: skip SIGTERM handler if NBD device support is not built
      nbd: disable signals and forking on Windows builds

Max Reitz (2):
      iotests/059: Fix reference output
      iotests/259: Fix reference output

Vladimir Sementsov-Ogievskiy (1):
      block/nbd: use non-blocking connect: fix vm hang on connect()

 block/nbd.c                | 266 ++++++++++++++++++++++++++++++++++++++++++++-
 qemu-img.c                 |   2 +
 qemu-io.c                  |   2 +
 qemu-nbd.c                 |  11 +-
 meson.build                |   7 +-
 tests/qemu-iotests/059.out |   2 +-
 tests/qemu-iotests/259.out |   2 +-
 7 files changed, 283 insertions(+), 9 deletions(-)

-- 
2.28.0

[PULL 1/6] iotests/059: Fix reference output

[Eric Blake]

From: Max Reitz <mreitz@redhat.com>

As of the patch to flush qemu-img's "Formatting" message before the
error message, 059 has been broken for vmdk.  Fix it.

Fixes: 4e2f4418784da09cb106264340241856cd2846df
       ("qemu-img: Flush stdout before before potential stderr messages")
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200811084150.326377-1-mreitz@redhat.com>
Reviewed-by: Eric blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 tests/qemu-iotests/059.out | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/059.out b/tests/qemu-iotests/059.out
index 6d127e28d8a6..2b83c0c8b66b 100644
--- a/tests/qemu-iotests/059.out
+++ b/tests/qemu-iotests/059.out
@@ -19,8 +19,8 @@ file format: IMGFMT
 virtual size: 2 GiB (2147483648 bytes)

 === Testing monolithicFlat with zeroed_grain ===
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2147483648
 qemu-img: TEST_DIR/t.IMGFMT: Flat image can't enable zeroed grain
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2147483648

 === Testing big twoGbMaxExtentFlat ===
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1073741824000
-- 
2.28.0

[PULL 2/6] iotests/259: Fix reference output

[Eric Blake]

From: Max Reitz <mreitz@redhat.com>

The error message has changed recently, breaking the test.  Fix it.

Fixes: a2b333c01880f56056d50c238834d62e32001e54
       ("block: nbd: Fix convert qcow2 compressed to nbd")
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200811080830.289136-1-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 tests/qemu-iotests/259.out | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/259.out b/tests/qemu-iotests/259.out
index e27b9ff38d75..1aaadfda4ead 100644
--- a/tests/qemu-iotests/259.out
+++ b/tests/qemu-iotests/259.out
@@ -10,5 +10,5 @@ disk size: unavailable

 --- Testing creation for which the node would need to grow ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=qcow2 size=67108864 preallocation=metadata
-qemu-img: TEST_DIR/t.IMGFMT: Could not resize image: Image format driver does not support resize
+qemu-img: TEST_DIR/t.IMGFMT: Could not resize image: Cannot grow NBD nodes
 *** done
-- 
2.28.0

[PULL 3/6] block/nbd: use non-blocking connect: fix vm hang on connect()

[Eric Blake]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

This makes nbd's connection_co yield during reconnects, so that
reconnect doesn't block the main thread. This is very important in
case of an unavailable nbd server host: connect() call may take a long
time, blocking the main thread (and due to reconnect, it will hang
again and again with small gaps of working time during pauses between
connection attempts).

Realization notes:

 - We don't want to implement non-blocking connect() over non-blocking
 socket, because getaddrinfo() doesn't have portable non-blocking
 realization anyway, so let's just use a thread for both getaddrinfo()
 and connect().

 - We can't use qio_channel_socket_connect_async (which behaves
 similarly and starts a thread to execute connect() call), as it's relying
 on someone iterating main loop (g_main_loop_run() or something like
 this), which is not always the case.

 - We can't use thread_pool_submit_co API, as thread pool waits for all
 threads to finish (but we don't want to wait for blocking reconnect
 attempt on shutdown.

 So, we just create the thread by hand. Some additional difficulties
 are:

 - We want our connect to avoid blocking drained sections and aio context
 switches. To achieve this, we make it possible to "cancel" synchronous
 wait for the connect (which is a coroutine yield actually), still,
 the thread continues in background, and if successful, its result may be
 reused on next reconnect attempt.

 - We don't want to wait for reconnect on shutdown, so there is
 CONNECT_THREAD_RUNNING_DETACHED thread state, which means that the block
 layer is no longer interested in a result, and thread should close new
 connected socket on finish and free the state.

How to reproduce the bug, fixed with this commit:

1. Create an image on node1:
   qemu-img create -f qcow2 xx 100M

2. Start NBD server on node1:
   qemu-nbd xx

3. Start vm with second nbd disk on node2, like this:

  ./x86_64-softmmu/qemu-system-x86_64 -nodefaults -drive \
    file=/work/images/cent7.qcow2 -drive file=nbd+tcp://192.168.100.2 \
    -vnc :0 -qmp stdio -m 2G -enable-kvm -vga std

4. Access the vm through vnc (or some other way?), and check that NBD
   drive works:

   dd if=/dev/sdb of=/dev/null bs=1M count=10

   - the command should succeed.

5. Now, let's trigger nbd-reconnect loop in Qemu process. For this:

5.1 Kill NBD server on node1

5.2 run "dd if=/dev/sdb of=/dev/null bs=1M count=10" in the guest
    again. The command should fail and a lot of error messages about
    failing disk may appear as well.

    Now NBD client driver in Qemu tries to reconnect.
    Still, VM works well.

6. Make node1 unavailable on NBD port, so connect() from node2 will
   last for a long time:

   On node1 (Note, that 10809 is just a default NBD port):

   sudo iptables -A INPUT -p tcp --dport 10809 -j DROP

   After some time the guest hangs, and you may check in gdb that Qemu
   hangs in connect() call, issued from the main thread. This is the
   BUG.

7. Don't forget to drop iptables rule from your node1:

   sudo iptables -D INPUT -p tcp --dport 10809 -j DROP

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200812145237.4396-1-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: minor wording and formatting tweaks]
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/nbd.c | 266 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 265 insertions(+), 1 deletion(-)

diff --git a/block/nbd.c b/block/nbd.c
index 7bb881fef49c..9daf003bea30 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -38,6 +38,7 @@

 #include "qapi/qapi-visit-sockets.h"
 #include "qapi/qmp/qstring.h"
+#include "qapi/clone-visitor.h"

 #include "block/qdict.h"
 #include "block/nbd.h"
@@ -62,6 +63,47 @@ typedef enum NBDClientState {
     NBD_CLIENT_QUIT
 } NBDClientState;

+typedef enum NBDConnectThreadState {
+    /* No thread, no pending results */
+    CONNECT_THREAD_NONE,
+
+    /* Thread is running, no results for now */
+    CONNECT_THREAD_RUNNING,
+
+    /*
+     * Thread is running, but requestor exited. Thread should close
+     * the new socket and free the connect state on exit.
+     */
+    CONNECT_THREAD_RUNNING_DETACHED,
+
+    /* Thread finished, results are stored in a state */
+    CONNECT_THREAD_FAIL,
+    CONNECT_THREAD_SUCCESS
+} NBDConnectThreadState;
+
+typedef struct NBDConnectThread {
+    /* Initialization constants */
+    SocketAddress *saddr; /* address to connect to */
+    /*
+     * Bottom half to schedule on completion. Scheduled only if bh_ctx is not
+     * NULL
+     */
+    QEMUBHFunc *bh_func;
+    void *bh_opaque;
+
+    /*
+     * Result of last attempt. Valid in FAIL and SUCCESS states.
+     * If you want to steal error, don't forget to set pointer to NULL.
+     */
+    QIOChannelSocket *sioc;
+    Error *err;
+
+    /* state and bh_ctx are protected by mutex */
+    QemuMutex mutex;
+    NBDConnectThreadState state; /* current state of the thread */
+    AioContext *bh_ctx; /* where to schedule bh (NULL means don't schedule) */
+} NBDConnectThread;
+
 typedef struct BDRVNBDState {
     QIOChannelSocket *sioc; /* The master data channel */
     QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
@@ -91,10 +133,17 @@ typedef struct BDRVNBDState {
     QCryptoTLSCreds *tlscreds;
     const char *hostname;
     char *x_dirty_bitmap;
+
+    bool wait_connect;
+    NBDConnectThread *connect_thread;
 } BDRVNBDState;

 static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
                                                   Error **errp);
+static QIOChannelSocket *nbd_co_establish_connection(BlockDriverState *bs,
+                                                     Error **errp);
+static void nbd_co_establish_connection_cancel(BlockDriverState *bs,
+                                               bool detach);
 static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc,
                                 Error **errp);

@@ -191,6 +240,8 @@ static void coroutine_fn nbd_client_co_drain_begin(BlockDriverState *bs)
     if (s->connection_co_sleep_ns_state) {
         qemu_co_sleep_wake(s->connection_co_sleep_ns_state);
     }
+
+    nbd_co_establish_connection_cancel(bs, false);
 }

 static void coroutine_fn nbd_client_co_drain_end(BlockDriverState *bs)
@@ -223,6 +274,7 @@ static void nbd_teardown_connection(BlockDriverState *bs)
         if (s->connection_co_sleep_ns_state) {
             qemu_co_sleep_wake(s->connection_co_sleep_ns_state);
         }
+        nbd_co_establish_connection_cancel(bs, true);
     }
     if (qemu_in_coroutine()) {
         s->teardown_co = qemu_coroutine_self();
@@ -246,6 +298,216 @@ static bool nbd_client_connecting_wait(BDRVNBDState *s)
     return s->state == NBD_CLIENT_CONNECTING_WAIT;
 }

+static void connect_bh(void *opaque)
+{
+    BDRVNBDState *state = opaque;
+
+    assert(state->wait_connect);
+    state->wait_connect = false;
+    aio_co_wake(state->connection_co);
+}
+
+static void nbd_init_connect_thread(BDRVNBDState *s)
+{
+    s->connect_thread = g_new(NBDConnectThread, 1);
+
+    *s->connect_thread = (NBDConnectThread) {
+        .saddr = QAPI_CLONE(SocketAddress, s->saddr),
+        .state = CONNECT_THREAD_NONE,
+        .bh_func = connect_bh,
+        .bh_opaque = s,
+    };
+
+    qemu_mutex_init(&s->connect_thread->mutex);
+}
+
+static void nbd_free_connect_thread(NBDConnectThread *thr)
+{
+    if (thr->sioc) {
+        qio_channel_close(QIO_CHANNEL(thr->sioc), NULL);
+    }
+    error_free(thr->err);
+    qapi_free_SocketAddress(thr->saddr);
+    g_free(thr);
+}
+
+static void *connect_thread_func(void *opaque)
+{
+    NBDConnectThread *thr = opaque;
+    int ret;
+    bool do_free = false;
+
+    thr->sioc = qio_channel_socket_new();
+
+    error_free(thr->err);
+    thr->err = NULL;
+    ret = qio_channel_socket_connect_sync(thr->sioc, thr->saddr, &thr->err);
+    if (ret < 0) {
+        object_unref(OBJECT(thr->sioc));
+        thr->sioc = NULL;
+    }
+
+    qemu_mutex_lock(&thr->mutex);
+
+    switch (thr->state) {
+    case CONNECT_THREAD_RUNNING:
+        thr->state = ret < 0 ? CONNECT_THREAD_FAIL : CONNECT_THREAD_SUCCESS;
+        if (thr->bh_ctx) {
+            aio_bh_schedule_oneshot(thr->bh_ctx, thr->bh_func, thr->bh_opaque);
+
+            /* play safe, don't reuse bh_ctx on further connection attempts */
+            thr->bh_ctx = NULL;
+        }
+        break;
+    case CONNECT_THREAD_RUNNING_DETACHED:
+        do_free = true;
+        break;
+    default:
+        abort();
+    }
+
+    qemu_mutex_unlock(&thr->mutex);
+
+    if (do_free) {
+        nbd_free_connect_thread(thr);
+    }
+
+    return NULL;
+}
+
+static QIOChannelSocket *coroutine_fn
+nbd_co_establish_connection(BlockDriverState *bs, Error **errp)
+{
+    QemuThread thread;
+    BDRVNBDState *s = bs->opaque;
+    QIOChannelSocket *res;
+    NBDConnectThread *thr = s->connect_thread;
+
+    qemu_mutex_lock(&thr->mutex);
+
+    switch (thr->state) {
+    case CONNECT_THREAD_FAIL:
+    case CONNECT_THREAD_NONE:
+        error_free(thr->err);
+        thr->err = NULL;
+        thr->state = CONNECT_THREAD_RUNNING;
+        qemu_thread_create(&thread, "nbd-connect",
+                           connect_thread_func, thr, QEMU_THREAD_DETACHED);
+        break;
+    case CONNECT_THREAD_SUCCESS:
+        /* Previous attempt finally succeeded in background */
+        thr->state = CONNECT_THREAD_NONE;
+        res = thr->sioc;
+        thr->sioc = NULL;
+        qemu_mutex_unlock(&thr->mutex);
+        return res;
+    case CONNECT_THREAD_RUNNING:
+        /* Already running, will wait */
+        break;
+    default:
+        abort();
+    }
+
+    thr->bh_ctx = qemu_get_current_aio_context();
+
+    qemu_mutex_unlock(&thr->mutex);
+
+
+    /*
+     * We are going to wait for connect-thread finish, but
+     * nbd_client_co_drain_begin() can interrupt.
+     *
+     * Note that wait_connect variable is not visible for connect-thread. It
+     * doesn't need mutex protection, it used only inside home aio context of
+     * bs.
+     */
+    s->wait_connect = true;
+    qemu_coroutine_yield();
+
+    qemu_mutex_lock(&thr->mutex);
+
+    switch (thr->state) {
+    case CONNECT_THREAD_SUCCESS:
+    case CONNECT_THREAD_FAIL:
+        thr->state = CONNECT_THREAD_NONE;
+        error_propagate(errp, thr->err);
+        thr->err = NULL;
+        res = thr->sioc;
+        thr->sioc = NULL;
+        break;
+    case CONNECT_THREAD_RUNNING:
+    case CONNECT_THREAD_RUNNING_DETACHED:
+        /*
+         * Obviously, drained section wants to start. Report the attempt as
+         * failed. Still connect thread is executing in background, and its
+         * result may be used for next connection attempt.
+         */
+        res = NULL;
+        error_setg(errp, "Connection attempt cancelled by other operation");
+        break;
+
+    case CONNECT_THREAD_NONE:
+        /*
+         * Impossible. We've seen this thread running. So it should be
+         * running or at least give some results.
+         */
+        abort();
+
+    default:
+        abort();
+    }
+
+    qemu_mutex_unlock(&thr->mutex);
+
+    return res;
+}
+
+/*
+ * nbd_co_establish_connection_cancel
+ * Cancel nbd_co_establish_connection asynchronously: it will finish soon, to
+ * allow drained section to begin.
+ *
+ * If detach is true, also cleanup the state (or if thread is running, move it
+ * to CONNECT_THREAD_RUNNING_DETACHED state). s->connect_thread becomes NULL if
+ * detach is true.
+ */
+static void nbd_co_establish_connection_cancel(BlockDriverState *bs,
+                                               bool detach)
+{
+    BDRVNBDState *s = bs->opaque;
+    NBDConnectThread *thr = s->connect_thread;
+    bool wake = false;
+    bool do_free = false;
+
+    qemu_mutex_lock(&thr->mutex);
+
+    if (thr->state == CONNECT_THREAD_RUNNING) {
+        /* We can cancel only in running state, when bh is not yet scheduled */
+        thr->bh_ctx = NULL;
+        if (s->wait_connect) {
+            s->wait_connect = false;
+            wake = true;
+        }
+        if (detach) {
+            thr->state = CONNECT_THREAD_RUNNING_DETACHED;
+            s->connect_thread = NULL;
+        }
+    } else if (detach) {
+        do_free = true;
+    }
+
+    qemu_mutex_unlock(&thr->mutex);
+
+    if (do_free) {
+        nbd_free_connect_thread(thr);
+        s->connect_thread = NULL;
+    }
+
+    if (wake) {
+        aio_co_wake(s->connection_co);
+    }
+}
+
 static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s)
 {
     int ret;
@@ -289,7 +551,7 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s)
         s->ioc = NULL;
     }

-    sioc = nbd_establish_connection(s->saddr, &local_err);
+    sioc = nbd_co_establish_connection(s->bs, &local_err);
     if (!sioc) {
         ret = -ECONNREFUSED;
         goto out;
@@ -1946,6 +2208,8 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
     /* successfully connected */
     s->state = NBD_CLIENT_CONNECTED;

+    nbd_init_connect_thread(s);
+
     s->connection_co = qemu_coroutine_create(nbd_connection_entry, s);
     bdrv_inc_in_flight(bs);
     aio_co_schedule(bdrv_get_aio_context(bs), s->connection_co);
-- 
2.28.0

[PULL 4/6] block: add missing socket_init() calls to tools

[Eric Blake]

From: Daniel P. Berrangé <berrange@redhat.com>

Any tool that uses sockets needs to call socket_init() in order to work
on the Windows platform.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200825103850.119911-2-berrange@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 qemu-img.c | 2 ++
 qemu-io.c  | 2 ++
 qemu-nbd.c | 1 +
 3 files changed, 5 insertions(+)

diff --git a/qemu-img.c b/qemu-img.c
index 5308773811f3..eb2fc1f86243 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -41,6 +41,7 @@
 #include "qemu/log.h"
 #include "qemu/main-loop.h"
 #include "qemu/module.h"
+#include "qemu/sockets.h"
 #include "qemu/units.h"
 #include "qom/object_interfaces.h"
 #include "sysemu/block-backend.h"
@@ -5410,6 +5411,7 @@ int main(int argc, char **argv)
     signal(SIGPIPE, SIG_IGN);
 #endif

+    socket_init();
     error_init(argv[0]);
     module_call_init(MODULE_INIT_TRACE);
     qemu_init_exec_dir(argv[0]);
diff --git a/qemu-io.c b/qemu-io.c
index 3adc5a7d0d3f..7cc832b3d618 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -25,6 +25,7 @@
 #include "qemu/config-file.h"
 #include "qemu/readline.h"
 #include "qemu/log.h"
+#include "qemu/sockets.h"
 #include "qapi/qmp/qstring.h"
 #include "qapi/qmp/qdict.h"
 #include "qom/object_interfaces.h"
@@ -542,6 +543,7 @@ int main(int argc, char **argv)
     signal(SIGPIPE, SIG_IGN);
 #endif

+    socket_init();
     error_init(argv[0]);
     module_call_init(MODULE_INIT_TRACE);
     qemu_init_exec_dir(argv[0]);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index d2657b8db50d..b102874f0f46 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -599,6 +599,7 @@ int main(int argc, char **argv)
     signal(SIGPIPE, SIG_IGN);
 #endif

+    socket_init();
     error_init(argv[0]);
     module_call_init(MODULE_INIT_TRACE);
     qcrypto_init(&error_fatal);
-- 
2.28.0

[PULL 5/6] nbd: skip SIGTERM handler if NBD device support is not built

[Eric Blake]

From: Daniel P. Berrangé <berrange@redhat.com>

The termsig_handler function is used by the client thread handling the
host NBD device connection to do a graceful shutdown. IOW, if we have
disabled NBD device support at compile time, we don't need the SIGTERM
handler. This fixes a build issue for Windows.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200825103850.119911-3-berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 qemu-nbd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/qemu-nbd.c b/qemu-nbd.c
index b102874f0f46..dc6ef089afd5 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -155,12 +155,13 @@ QEMU_COPYRIGHT "\n"
     , name);
 }

+#if HAVE_NBD_DEVICE
 static void termsig_handler(int signum)
 {
     atomic_cmpxchg(&state, RUNNING, TERMINATE);
     qemu_notify_event();
 }
-
+#endif /* HAVE_NBD_DEVICE */

 static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
                                 const char *hostname)
@@ -587,6 +588,7 @@ int main(int argc, char **argv)
     unsigned socket_activation;
     const char *pid_file_name = NULL;

+#if HAVE_NBD_DEVICE
     /* The client thread uses SIGTERM to interrupt the server.  A signal
      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
      */
@@ -594,6 +596,7 @@ int main(int argc, char **argv)
     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
     sa_sigterm.sa_handler = termsig_handler;
     sigaction(SIGTERM, &sa_sigterm, NULL);
+#endif /* HAVE_NBD_DEVICE */

 #ifdef CONFIG_POSIX
     signal(SIGPIPE, SIG_IGN);
-- 
2.28.0

[PULL 6/6] nbd: disable signals and forking on Windows builds

[Eric Blake]

From: Daniel P. Berrangé <berrange@redhat.com>

Disabling these parts are sufficient to get the qemu-nbd program
compiling in a Windows build.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200825103850.119911-4-berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 qemu-nbd.c  | 5 +++++
 meson.build | 7 ++-----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/qemu-nbd.c b/qemu-nbd.c
index dc6ef089afd5..33476a1000c8 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -899,6 +899,7 @@ int main(int argc, char **argv)
 #endif

     if ((device && !verbose) || fork_process) {
+#ifndef WIN32
         int stderr_fd[2];
         pid_t pid;
         int ret;
@@ -962,6 +963,10 @@ int main(int argc, char **argv)
              */
             exit(errors);
         }
+#else /* WIN32 */
+        error_report("Unable to fork into background on Windows hosts");
+        exit(EXIT_FAILURE);
+#endif /* WIN32 */
     }

     if (device != NULL && sockpath == NULL) {
diff --git a/meson.build b/meson.build
index 55c7d2318cdb..5aaa3647305d 100644
--- a/meson.build
+++ b/meson.build
@@ -1095,12 +1095,9 @@ if have_tools
              dependencies: [authz, block, crypto, io, qom, qemuutil], install: true)
   qemu_io = executable('qemu-io', files('qemu-io.c'),
              dependencies: [block, qemuutil], install: true)
-  qemu_block_tools += [qemu_img, qemu_io]
-  if targetos != 'windows'
-    qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
+  qemu_nbd = executable('qemu-nbd', files('qemu-nbd.c'),
                dependencies: [block, qemuutil], install: true)
-    qemu_block_tools += [qemu_nbd]
-  endif
+  qemu_block_tools += [qemu_img, qemu_io, qemu_nbd]

   subdir('storage-daemon')
   subdir('contrib/rdmacm-mux')
-- 
2.28.0

Re: [PULL 0/6] NBD patches for 2020-09-02

[Peter Maydell]

On Wed, 2 Sep 2020 at 22:58, Eric Blake <eblake@redhat.com> wrote:
>
> The following changes since commit ed215cec0fcaeaece064b0fdf37fe3bceb06d76c:
>
>   Merge remote-tracking branch 'remotes/ehabkost/tags/machine-next-pull-request' into staging (2020-09-02 15:26:38 +0100)
>
> are available in the Git repository at:
>
>   https://repo.or.cz/qemu/ericb.git tags/pull-nbd-2020-09-02
>
> for you to fetch changes up to eb705985f43d631438a318f1146eac61ae10d273:
>
>   nbd: disable signals and forking on Windows builds (2020-09-02 16:48:21 -0500)
>
> ----------------------------------------------------------------
> nbd patches for 2020-09-02
>
> - fix a few iotests affected by earlier nbd changes
> - avoid blocking qemu by nbd client in connect()
> - build qemu-nbd for mingw
>
> ----------------------------------------------------------------


Applied, thanks.

Please update the changelog at https://wiki.qemu.org/ChangeLog/5.2
for any user-visible changes.

-- PMM