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authorPaolo Bonzini <pbonzini@redhat.com>2012-08-22 16:43:07 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2012-10-23 22:39:33 +0200
commit6dd844db4a49a367cc15cd0e8bfb72cfc6652766 (patch)
tree5a3a8ef535d4055ee0ec62a1cf6edb6c8a34ff9b /blockdev-nbd.c
parentd7d512f60979681c27597f1b1277e03505c1de08 (diff)
downloadqemu-arm-6dd844db4a49a367cc15cd0e8bfb72cfc6652766.tar.gz
qmp: add NBD server commands
Adding an NBD server inside QEMU is trivial, since all the logic is in nbd.c and can be shared easily between qemu-nbd and QEMU itself. The main difference is that qemu-nbd serves a single unnamed export, while QEMU serves named exports. Acked-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'blockdev-nbd.c')
-rw-r--r--blockdev-nbd.c119
1 files changed, 119 insertions, 0 deletions
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
new file mode 100644
index 0000000000..8031813071
--- /dev/null
+++ b/blockdev-nbd.c
@@ -0,0 +1,119 @@
+/*
+ * Serving QEMU block devices via NBD
+ *
+ * Copyright (c) 2012 Red Hat, Inc.
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later. See the COPYING file in the top-level directory.
+ */
+
+#include "blockdev.h"
+#include "hw/block-common.h"
+#include "monitor.h"
+#include "qerror.h"
+#include "sysemu.h"
+#include "qmp-commands.h"
+#include "trace.h"
+#include "nbd.h"
+#include "qemu_socket.h"
+
+static int server_fd = -1;
+
+static void nbd_accept(void *opaque)
+{
+ struct sockaddr_in addr;
+ socklen_t addr_len = sizeof(addr);
+
+ int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
+ if (fd >= 0) {
+ nbd_client_new(NULL, fd, nbd_client_put);
+ }
+}
+
+void qmp_nbd_server_start(SocketAddress *addr, Error **errp)
+{
+ if (server_fd != -1) {
+ error_setg(errp, "NBD server already running");
+ return;
+ }
+
+ server_fd = socket_listen(addr, errp);
+ if (server_fd != -1) {
+ qemu_set_fd_handler2(server_fd, NULL, nbd_accept, NULL, NULL);
+ }
+}
+
+/* Hook into the BlockDriverState notifiers to close the export when
+ * the file is closed.
+ */
+typedef struct NBDCloseNotifier {
+ Notifier n;
+ NBDExport *exp;
+ QTAILQ_ENTRY(NBDCloseNotifier) next;
+} NBDCloseNotifier;
+
+static QTAILQ_HEAD(, NBDCloseNotifier) close_notifiers =
+ QTAILQ_HEAD_INITIALIZER(close_notifiers);
+
+static void nbd_close_notifier(Notifier *n, void *data)
+{
+ NBDCloseNotifier *cn = DO_UPCAST(NBDCloseNotifier, n, n);
+
+ notifier_remove(&cn->n);
+ QTAILQ_REMOVE(&close_notifiers, cn, next);
+
+ nbd_export_close(cn->exp);
+ nbd_export_put(cn->exp);
+ g_free(cn);
+}
+
+static void nbd_server_put_ref(NBDExport *exp)
+{
+ BlockDriverState *bs = nbd_export_get_blockdev(exp);
+ drive_put_ref(drive_get_by_blockdev(bs));
+}
+
+void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
+ Error **errp)
+{
+ BlockDriverState *bs;
+ NBDExport *exp;
+ NBDCloseNotifier *n;
+
+ if (nbd_export_find(device)) {
+ error_setg(errp, "NBD server already exporting device '%s'", device);
+ return;
+ }
+
+ bs = bdrv_find(device);
+ if (!bs) {
+ error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+ return;
+ }
+
+ exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY,
+ nbd_server_put_ref);
+
+ nbd_export_set_name(exp, device);
+ drive_get_ref(drive_get_by_blockdev(bs));
+
+ n = g_malloc0(sizeof(NBDCloseNotifier));
+ n->n.notify = nbd_close_notifier;
+ n->exp = exp;
+ bdrv_add_close_notifier(bs, &n->n);
+ QTAILQ_INSERT_TAIL(&close_notifiers, n, next);
+}
+
+void qmp_nbd_server_stop(Error **errp)
+{
+ while (!QTAILQ_EMPTY(&close_notifiers)) {
+ NBDCloseNotifier *cn = QTAILQ_FIRST(&close_notifiers);
+ nbd_close_notifier(&cn->n, nbd_export_get_blockdev(cn->exp));
+ }
+
+ qemu_set_fd_handler2(server_fd, NULL, NULL, NULL, NULL);
+ close(server_fd);
+ server_fd = -1;
+}