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[PATCH v4 20/32] nbd/client-connection: implement connection retry
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[PATCH v4 20/32] nbd/client-connection: implement connection retry |
Date: |
Thu, 10 Jun 2021 13:07:50 +0300 |
Add an option for a thread to retry connection until succeeds. We'll
use nbd/client-connection both for reconnect and for initial connection
in nbd_open(), so we need a possibility to use same NBDClientConnection
instance to connect once in nbd_open() and then use retry semantics for
reconnect.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
include/block/nbd.h | 2 ++
nbd/client-connection.c | 56 +++++++++++++++++++++++++++++++----------
2 files changed, 45 insertions(+), 13 deletions(-)
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 5d86e6a393..5bb54d831c 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -409,6 +409,8 @@ const char *nbd_err_lookup(int err);
/* nbd/client-connection.c */
typedef struct NBDClientConnection NBDClientConnection;
+void nbd_client_connection_enable_retry(NBDClientConnection *conn);
+
NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr,
bool do_negotiation,
const char *export_name,
diff --git a/nbd/client-connection.c b/nbd/client-connection.c
index 4301099f1b..76346481ba 100644
--- a/nbd/client-connection.c
+++ b/nbd/client-connection.c
@@ -35,6 +35,7 @@ struct NBDClientConnection {
QCryptoTLSCreds *tlscreds;
NBDExportInfo initial_info;
bool do_negotiation;
+ bool do_retry;
QemuMutex mutex;
@@ -60,6 +61,15 @@ struct NBDClientConnection {
Coroutine *wait_co;
};
+/*
+ * The function isn't protected by any mutex, only call it when the client
+ * connection attempt has not yet started.
+ */
+void nbd_client_connection_enable_retry(NBDClientConnection *conn)
+{
+ conn->do_retry = true;
+}
+
NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr,
bool do_negotiation,
const char *export_name,
@@ -154,23 +164,43 @@ static void *connect_thread_func(void *opaque)
NBDClientConnection *conn = opaque;
int ret;
bool do_free;
+ uint64_t timeout = 1;
+ uint64_t max_timeout = 16;
- conn->sioc = qio_channel_socket_new();
+ while (true) {
+ conn->sioc = qio_channel_socket_new();
- error_free(conn->err);
- conn->err = NULL;
- conn->updated_info = conn->initial_info;
+ error_free(conn->err);
+ conn->err = NULL;
+ conn->updated_info = conn->initial_info;
- ret = nbd_connect(conn->sioc, conn->saddr,
- conn->do_negotiation ? &conn->updated_info : NULL,
- conn->tlscreds, &conn->ioc, &conn->err);
- if (ret < 0) {
- object_unref(OBJECT(conn->sioc));
- conn->sioc = NULL;
- }
+ ret = nbd_connect(conn->sioc, conn->saddr,
+ conn->do_negotiation ? &conn->updated_info : NULL,
+ conn->tlscreds, &conn->ioc, &conn->err);
+
+ /*
+ * conn->updated_info will finally be returned to the user. Clear the
+ * pointers to our internally allocated strings, which are IN
parameters
+ * of nbd_receive_negotiate() and therefore nbd_connect(). Caller
+ * shoudn't be interested in these fields.
+ */
+ conn->updated_info.x_dirty_bitmap = NULL;
+ conn->updated_info.name = NULL;
+
+ if (ret < 0) {
+ object_unref(OBJECT(conn->sioc));
+ conn->sioc = NULL;
+ if (conn->do_retry) {
+ sleep(timeout);
+ if (timeout < max_timeout) {
+ timeout *= 2;
+ }
+ continue;
+ }
+ }
- conn->updated_info.x_dirty_bitmap = NULL;
- conn->updated_info.name = NULL;
+ break;
+ }
qemu_mutex_lock(&conn->mutex);
--
2.29.2
- Re: [PATCH v4 05/32] qemu-sockets: introduce socket_address_parse_named_fd(), (continued)
- [PATCH v4 13/32] block/nbd: make nbd_co_establish_connection_cancel() bs-independent, Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 15/32] block/nbd: introduce nbd_client_connection_new(), Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 21/32] nbd/client-connection: shutdown connection on release, Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 25/32] block/nbd: drop BDRVNBDState::sioc, Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 27/32] block-coroutine-wrapper: allow non bdrv_ prefix, Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 16/32] block/nbd: introduce nbd_client_connection_release(), Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 20/32] nbd/client-connection: implement connection retry,
Vladimir Sementsov-Ogievskiy <=
- [PATCH v4 28/32] block/nbd: split nbd_co_do_establish_connection out of nbd_reconnect_attempt, Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 23/32] block/nbd: use negotiation of NBDClientConnection, Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 22/32] block/nbd: split nbd_handle_updated_info out of nbd_client_handshake(), Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 14/32] block/nbd: rename NBDConnectThread to NBDClientConnection, Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 26/32] nbd/client-connection: return only one io channel, Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 31/32] block/nbd: add nbd_client_connected() helper, Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 24/32] block/nbd: don't touch s->sioc in nbd_teardown_connection(), Vladimir Sementsov-Ogievskiy, 2021/06/10
- [PATCH v4 29/32] nbd/client-connection: add option for non-blocking connection attempt, Vladimir Sementsov-Ogievskiy, 2021/06/10