[Qemu-devel] [PATCH v5 0/6] NBD reconnect: prep. refactoring

[Qemu-devel] [PATCH v5 0/6] NBD reconnect: prep. refactoring

[Vladimir Sementsov-Ogievskiy]

Hi all.

Here is most of preparatory refactoring for NBD reconnect, rebased
on master. Let's push it.

Sorry for a long delay in answering on v4 review and for v4 which
I pinged a lot can't be applied on master directly :(

v5:
02: rebased on master, object_unref() moved to fail: block
05: tiny fixes in commit message [Eric]

Vladimir Sementsov-Ogievskiy (6):
  block/nbd-client: split channel errors from export errors
  block/nbd: move connection code from block/nbd to block/nbd-client
  block/nbd-client: split connection from initialization
  block/nbd-client: fix nbd_reply_chunk_iter_receive
  block/nbd-client: don't check ioc
  block/nbd-client: rename read_reply_co to connection_co

 block/nbd-client.h |   6 +-
 block/nbd-client.c | 196 +++++++++++++++++++++++++++++----------------
 block/nbd.c        |  40 +--------
 3 files changed, 131 insertions(+), 111 deletions(-)

-- 
2.18.0

[Qemu-devel] [PATCH v5 1/6] block/nbd-client: split channel errors from export errors

[Vladimir Sementsov-Ogievskiy]

To implement nbd reconnect in further patches, we need to distinguish
error codes, returned by nbd server, from channel errors, to reconnect
only in the latter case.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/nbd-client.c | 83 ++++++++++++++++++++++++++--------------------
 1 file changed, 47 insertions(+), 36 deletions(-)

diff --git a/block/nbd-client.c b/block/nbd-client.c
index 813539676d..b023a35d1d 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -504,11 +504,11 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
  */
 static coroutine_fn int nbd_co_receive_one_chunk(
         NBDClientSession *s, uint64_t handle, bool only_structured,
-        QEMUIOVector *qiov, NBDReply *reply, void **payload, Error **errp)
+        int *request_ret, QEMUIOVector *qiov, NBDReply *reply, void **payload,
+        Error **errp)
 {
-    int request_ret;
     int ret = nbd_co_do_receive_one_chunk(s, handle, only_structured,
-                                          &request_ret, qiov, payload, errp);
+                                          request_ret, qiov, payload, errp);
 
     if (ret < 0) {
         s->quit = true;
@@ -518,7 +518,6 @@ static coroutine_fn int nbd_co_receive_one_chunk(
             *reply = s->reply;
         }
         s->reply.handle = 0;
-        ret = request_ret;
     }
 
     if (s->read_reply_co) {
@@ -530,22 +529,17 @@ static coroutine_fn int nbd_co_receive_one_chunk(
 
 typedef struct NBDReplyChunkIter {
     int ret;
-    bool fatal;
+    int request_ret;
     Error *err;
     bool done, only_structured;
 } NBDReplyChunkIter;
 
-static void nbd_iter_error(NBDReplyChunkIter *iter, bool fatal,
-                           int ret, Error **local_err)
+static void nbd_iter_channel_error(NBDReplyChunkIter *iter,
+                                   int ret, Error **local_err)
 {
     assert(ret < 0);
 
-    if ((fatal && !iter->fatal) || iter->ret == 0) {
-        if (iter->ret != 0) {
-            error_free(iter->err);
-            iter->err = NULL;
-        }
-        iter->fatal = fatal;
+    if (!iter->ret) {
         iter->ret = ret;
         error_propagate(&iter->err, *local_err);
     } else {
@@ -555,6 +549,15 @@ static void nbd_iter_error(NBDReplyChunkIter *iter, bool fatal,
     *local_err = NULL;
 }
 
+static void nbd_iter_request_error(NBDReplyChunkIter *iter, int ret)
+{
+    assert(ret < 0);
+
+    if (!iter->request_ret) {
+        iter->request_ret = ret;
+    }
+}
+
 /* NBD_FOREACH_REPLY_CHUNK
  */
 #define NBD_FOREACH_REPLY_CHUNK(s, iter, handle, structured, \
@@ -570,13 +573,13 @@ static bool nbd_reply_chunk_iter_receive(NBDClientSession *s,
                                          QEMUIOVector *qiov, NBDReply *reply,
                                          void **payload)
 {
-    int ret;
+    int ret, request_ret;
     NBDReply local_reply;
     NBDStructuredReplyChunk *chunk;
     Error *local_err = NULL;
     if (s->quit) {
         error_setg(&local_err, "Connection closed");
-        nbd_iter_error(iter, true, -EIO, &local_err);
+        nbd_iter_channel_error(iter, -EIO, &local_err);
         goto break_loop;
     }
 
@@ -590,10 +593,12 @@ static bool nbd_reply_chunk_iter_receive(NBDClientSession *s,
     }
 
     ret = nbd_co_receive_one_chunk(s, handle, iter->only_structured,
-                                   qiov, reply, payload, &local_err);
+                                   &request_ret, qiov, reply, payload,
+                                   &local_err);
     if (ret < 0) {
-        /* If it is a fatal error s->quit is set by nbd_co_receive_one_chunk */
-        nbd_iter_error(iter, s->quit, ret, &local_err);
+        nbd_iter_channel_error(iter, ret, &local_err);
+    } else if (request_ret < 0) {
+        nbd_iter_request_error(iter, request_ret);
     }
 
     /* Do not execute the body of NBD_FOREACH_REPLY_CHUNK for simple reply. */
@@ -630,7 +635,7 @@ break_loop:
 }
 
 static int nbd_co_receive_return_code(NBDClientSession *s, uint64_t handle,
-                                      Error **errp)
+                                      int *request_ret, Error **errp)
 {
     NBDReplyChunkIter iter;
 
@@ -639,12 +644,13 @@ static int nbd_co_receive_return_code(NBDClientSession *s, uint64_t handle,
     }
 
     error_propagate(errp, iter.err);
+    *request_ret = iter.request_ret;
     return iter.ret;
 }
 
 static int nbd_co_receive_cmdread_reply(NBDClientSession *s, uint64_t handle,
                                         uint64_t offset, QEMUIOVector *qiov,
-                                        Error **errp)
+                                        int *request_ret, Error **errp)
 {
     NBDReplyChunkIter iter;
     NBDReply reply;
@@ -669,7 +675,7 @@ static int nbd_co_receive_cmdread_reply(NBDClientSession *s, uint64_t handle,
                                                 offset, qiov, &local_err);
             if (ret < 0) {
                 s->quit = true;
-                nbd_iter_error(&iter, true, ret, &local_err);
+                nbd_iter_channel_error(&iter, ret, &local_err);
             }
             break;
         default:
@@ -679,7 +685,7 @@ static int nbd_co_receive_cmdread_reply(NBDClientSession *s, uint64_t handle,
                 error_setg(&local_err,
                            "Unexpected reply type: %d (%s) for CMD_READ",
                            chunk->type, nbd_reply_type_lookup(chunk->type));
-                nbd_iter_error(&iter, true, -EINVAL, &local_err);
+                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
             }
         }
 
@@ -688,12 +694,14 @@ static int nbd_co_receive_cmdread_reply(NBDClientSession *s, uint64_t handle,
     }
 
     error_propagate(errp, iter.err);
+    *request_ret = iter.request_ret;
     return iter.ret;
 }
 
 static int nbd_co_receive_blockstatus_reply(NBDClientSession *s,
                                             uint64_t handle, uint64_t length,
-                                            NBDExtent *extent, Error **errp)
+                                            NBDExtent *extent,
+                                            int *request_ret, Error **errp)
 {
     NBDReplyChunkIter iter;
     NBDReply reply;
@@ -715,7 +723,7 @@ static int nbd_co_receive_blockstatus_reply(NBDClientSession *s,
             if (received) {
                 s->quit = true;
                 error_setg(&local_err, "Several BLOCK_STATUS chunks in reply");
-                nbd_iter_error(&iter, true, -EINVAL, &local_err);
+                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
             }
             received = true;
 
@@ -724,7 +732,7 @@ static int nbd_co_receive_blockstatus_reply(NBDClientSession *s,
                                                 &local_err);
             if (ret < 0) {
                 s->quit = true;
-                nbd_iter_error(&iter, true, ret, &local_err);
+                nbd_iter_channel_error(&iter, ret, &local_err);
             }
             break;
         default:
@@ -734,7 +742,7 @@ static int nbd_co_receive_blockstatus_reply(NBDClientSession *s,
                            "Unexpected reply type: %d (%s) "
                            "for CMD_BLOCK_STATUS",
                            chunk->type, nbd_reply_type_lookup(chunk->type));
-                nbd_iter_error(&iter, true, -EINVAL, &local_err);
+                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
             }
         }
 
@@ -749,14 +757,16 @@ static int nbd_co_receive_blockstatus_reply(NBDClientSession *s,
             iter.ret = -EIO;
         }
     }
+
     error_propagate(errp, iter.err);
+    *request_ret = iter.request_ret;
     return iter.ret;
 }
 
 static int nbd_co_request(BlockDriverState *bs, NBDRequest *request,
                           QEMUIOVector *write_qiov)
 {
-    int ret;
+    int ret, request_ret;
     Error *local_err = NULL;
     NBDClientSession *client = nbd_get_client_session(bs);
 
@@ -772,7 +782,8 @@ static int nbd_co_request(BlockDriverState *bs, NBDRequest *request,
         return ret;
     }
 
-    ret = nbd_co_receive_return_code(client, request->handle, &local_err);
+    ret = nbd_co_receive_return_code(client, request->handle,
+                                     &request_ret, &local_err);
     if (local_err) {
         trace_nbd_co_request_fail(request->from, request->len, request->handle,
                                   request->flags, request->type,
@@ -780,13 +791,13 @@ static int nbd_co_request(BlockDriverState *bs, NBDRequest *request,
                                   ret, error_get_pretty(local_err));
         error_free(local_err);
     }
-    return ret;
+    return ret ? ret : request_ret;
 }
 
 int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
                          uint64_t bytes, QEMUIOVector *qiov, int flags)
 {
-    int ret;
+    int ret, request_ret;
     Error *local_err = NULL;
     NBDClientSession *client = nbd_get_client_session(bs);
     NBDRequest request = {
@@ -807,7 +818,7 @@ int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
     }
 
     ret = nbd_co_receive_cmdread_reply(client, request.handle, offset, qiov,
-                                       &local_err);
+                                       &request_ret, &local_err);
     if (local_err) {
         trace_nbd_co_request_fail(request.from, request.len, request.handle,
                                   request.flags, request.type,
@@ -815,7 +826,7 @@ int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
                                   ret, error_get_pretty(local_err));
         error_free(local_err);
     }
-    return ret;
+    return ret ? ret : request_ret;
 }
 
 int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset,
@@ -909,7 +920,7 @@ int coroutine_fn nbd_client_co_block_status(BlockDriverState *bs,
                                             int64_t *pnum, int64_t *map,
                                             BlockDriverState **file)
 {
-    int64_t ret;
+    int ret, request_ret;
     NBDExtent extent = { 0 };
     NBDClientSession *client = nbd_get_client_session(bs);
     Error *local_err = NULL;
@@ -934,7 +945,7 @@ int coroutine_fn nbd_client_co_block_status(BlockDriverState *bs,
     }
 
     ret = nbd_co_receive_blockstatus_reply(client, request.handle, bytes,
-                                           &extent, &local_err);
+                                           &extent, &request_ret, &local_err);
     if (local_err) {
         trace_nbd_co_request_fail(request.from, request.len, request.handle,
                                   request.flags, request.type,
@@ -942,8 +953,8 @@ int coroutine_fn nbd_client_co_block_status(BlockDriverState *bs,
                                   ret, error_get_pretty(local_err));
         error_free(local_err);
     }
-    if (ret < 0) {
-        return ret;
+    if (ret < 0 || request_ret < 0) {
+        return ret ? ret : request_ret;
     }
 
     assert(extent.length);
-- 
2.18.0

[Qemu-devel] [PATCH v5 2/6] block/nbd: move connection code from block/nbd to block/nbd-client

[Vladimir Sementsov-Ogievskiy]

Keep all connection code in one file, to be able to implement reconnect
in further patches.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---

Notes:
    v5:
    rebase on master, object_unref under fail:.
    fix comment to "/*\n" style.

 block/nbd-client.h |  2 +-
 block/nbd-client.c | 40 ++++++++++++++++++++++++++++++++++++++--
 block/nbd.c        | 40 ++--------------------------------------
 3 files changed, 41 insertions(+), 41 deletions(-)

diff --git a/block/nbd-client.h b/block/nbd-client.h
index cfc90550b9..2f047ba614 100644
--- a/block/nbd-client.h
+++ b/block/nbd-client.h
@@ -41,7 +41,7 @@ typedef struct NBDClientSession {
 NBDClientSession *nbd_get_client_session(BlockDriverState *bs);
 
 int nbd_client_init(BlockDriverState *bs,
-                    QIOChannelSocket *sock,
+                    SocketAddress *saddr,
                     const char *export_name,
                     QCryptoTLSCreds *tlscreds,
                     const char *hostname,
diff --git a/block/nbd-client.c b/block/nbd-client.c
index b023a35d1d..641666d3bc 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -991,8 +991,31 @@ void nbd_client_close(BlockDriverState *bs)
     nbd_teardown_connection(bs);
 }
 
+static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
+                                                  Error **errp)
+{
+    QIOChannelSocket *sioc;
+    Error *local_err = NULL;
+
+    sioc = qio_channel_socket_new();
+    qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
+
+    qio_channel_socket_connect_sync(sioc,
+                                    saddr,
+                                    &local_err);
+    if (local_err) {
+        object_unref(OBJECT(sioc));
+        error_propagate(errp, local_err);
+        return NULL;
+    }
+
+    qio_channel_set_delay(QIO_CHANNEL(sioc), false);
+
+    return sioc;
+}
+
 int nbd_client_init(BlockDriverState *bs,
-                    QIOChannelSocket *sioc,
+                    SocketAddress *saddr,
                     const char *export,
                     QCryptoTLSCreds *tlscreds,
                     const char *hostname,
@@ -1002,6 +1025,16 @@ int nbd_client_init(BlockDriverState *bs,
     NBDClientSession *client = nbd_get_client_session(bs);
     int ret;
 
+    /*
+     * establish TCP connection, return error if it fails
+     * TODO: Configurable retry-until-timeout behaviour.
+     */
+    QIOChannelSocket *sioc = nbd_establish_connection(saddr, errp);
+
+    if (!sioc) {
+        return -ECONNREFUSED;
+    }
+
     /* NBD handshake */
     logout("session init %s\n", export);
     qio_channel_set_blocking(QIO_CHANNEL(sioc), true, NULL);
@@ -1017,6 +1050,7 @@ int nbd_client_init(BlockDriverState *bs,
     g_free(client->info.name);
     if (ret < 0) {
         logout("Failed to negotiate with the NBD server\n");
+        object_unref(OBJECT(sioc));
         return ret;
     }
     if (x_dirty_bitmap && !client->info.base_allocation) {
@@ -1042,7 +1076,6 @@ int nbd_client_init(BlockDriverState *bs,
     qemu_co_mutex_init(&client->send_mutex);
     qemu_co_queue_init(&client->free_sema);
     client->sioc = sioc;
-    object_ref(OBJECT(client->sioc));
 
     if (!client->ioc) {
         client->ioc = QIO_CHANNEL(sioc);
@@ -1068,6 +1101,9 @@ int nbd_client_init(BlockDriverState *bs,
         NBDRequest request = { .type = NBD_CMD_DISC };
 
         nbd_send_request(client->ioc ?: QIO_CHANNEL(sioc), &request);
+
+        object_unref(OBJECT(sioc));
+
         return ret;
     }
 }
diff --git a/block/nbd.c b/block/nbd.c
index e87699fb73..9db5eded89 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -295,30 +295,6 @@ NBDClientSession *nbd_get_client_session(BlockDriverState *bs)
     return &s->client;
 }
 
-static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
-                                                  Error **errp)
-{
-    QIOChannelSocket *sioc;
-    Error *local_err = NULL;
-
-    sioc = qio_channel_socket_new();
-    qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
-
-    qio_channel_socket_connect_sync(sioc,
-                                    saddr,
-                                    &local_err);
-    if (local_err) {
-        object_unref(OBJECT(sioc));
-        error_propagate(errp, local_err);
-        return NULL;
-    }
-
-    qio_channel_set_delay(QIO_CHANNEL(sioc), false);
-
-    return sioc;
-}
-
-
 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 {
     Object *obj;
@@ -394,7 +370,6 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
     BDRVNBDState *s = bs->opaque;
     QemuOpts *opts = NULL;
     Error *local_err = NULL;
-    QIOChannelSocket *sioc = NULL;
     QCryptoTLSCreds *tlscreds = NULL;
     const char *hostname = NULL;
     int ret = -EINVAL;
@@ -434,22 +409,11 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
         hostname = s->saddr->u.inet.host;
     }
 
-    /* establish TCP connection, return error if it fails
-     * TODO: Configurable retry-until-timeout behaviour.
-     */
-    sioc = nbd_establish_connection(s->saddr, errp);
-    if (!sioc) {
-        ret = -ECONNREFUSED;
-        goto error;
-    }
-
     /* NBD handshake */
-    ret = nbd_client_init(bs, sioc, s->export, tlscreds, hostname,
+    ret = nbd_client_init(bs, s->saddr, s->export, tlscreds, hostname,
                           qemu_opt_get(opts, "x-dirty-bitmap"), errp);
+
  error:
-    if (sioc) {
-        object_unref(OBJECT(sioc));
-    }
     if (tlscreds) {
         object_unref(OBJECT(tlscreds));
     }
-- 
2.18.0

[Qemu-devel] [PATCH v5 3/6] block/nbd-client: split connection from initialization

[Vladimir Sementsov-Ogievskiy]

Split connection code to reuse it for reconnect.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/nbd-client.c | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/block/nbd-client.c b/block/nbd-client.c
index 641666d3bc..a8ce0824c2 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -1014,13 +1014,13 @@ static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
     return sioc;
 }
 
-int nbd_client_init(BlockDriverState *bs,
-                    SocketAddress *saddr,
-                    const char *export,
-                    QCryptoTLSCreds *tlscreds,
-                    const char *hostname,
-                    const char *x_dirty_bitmap,
-                    Error **errp)
+static int nbd_client_connect(BlockDriverState *bs,
+                              SocketAddress *saddr,
+                              const char *export,
+                              QCryptoTLSCreds *tlscreds,
+                              const char *hostname,
+                              const char *x_dirty_bitmap,
+                              Error **errp)
 {
     NBDClientSession *client = nbd_get_client_session(bs);
     int ret;
@@ -1073,8 +1073,6 @@ int nbd_client_init(BlockDriverState *bs,
         bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP;
     }
 
-    qemu_co_mutex_init(&client->send_mutex);
-    qemu_co_queue_init(&client->free_sema);
     client->sioc = sioc;
 
     if (!client->ioc) {
@@ -1107,3 +1105,20 @@ int nbd_client_init(BlockDriverState *bs,
         return ret;
     }
 }
+
+int nbd_client_init(BlockDriverState *bs,
+                    SocketAddress *saddr,
+                    const char *export,
+                    QCryptoTLSCreds *tlscreds,
+                    const char *hostname,
+                    const char *x_dirty_bitmap,
+                    Error **errp)
+{
+    NBDClientSession *client = nbd_get_client_session(bs);
+
+    qemu_co_mutex_init(&client->send_mutex);
+    qemu_co_queue_init(&client->free_sema);
+
+    return nbd_client_connect(bs, saddr, export, tlscreds, hostname,
+                              x_dirty_bitmap, errp);
+}
-- 
2.18.0

[Qemu-devel] [PATCH v5 4/6] block/nbd-client: fix nbd_reply_chunk_iter_receive

[Vladimir Sementsov-Ogievskiy]

Use exported report, not the variable to be reused (should not really
matter).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/nbd-client.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/nbd-client.c b/block/nbd-client.c
index a8ce0824c2..8e9b3dbedd 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -602,7 +602,7 @@ static bool nbd_reply_chunk_iter_receive(NBDClientSession *s,
     }
 
     /* Do not execute the body of NBD_FOREACH_REPLY_CHUNK for simple reply. */
-    if (nbd_reply_is_simple(&s->reply) || s->quit) {
+    if (nbd_reply_is_simple(reply) || s->quit) {
         goto break_loop;
     }
 
-- 
2.18.0

[Qemu-devel] [PATCH v5 5/6] block/nbd-client: don't check ioc

[Vladimir Sementsov-Ogievskiy]

We have several paranoid checks for ioc != NULL. But ioc may become
NULL only on close, which should not happen during requests handling.
Also, we check ioc only sometimes, not after each yield, which is
inconsistent. Let's drop these checks. However, for safety, let's leave
asserts instead.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---

Notes:
    v5: fix commit message a bit [Eric]

 block/nbd-client.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/block/nbd-client.c b/block/nbd-client.c
index 8e9b3dbedd..d8bf1bbb8b 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -53,9 +53,7 @@ static void nbd_teardown_connection(BlockDriverState *bs)
 {
     NBDClientSession *client = nbd_get_client_session(bs);
 
-    if (!client->ioc) { /* Already closed */
-        return;
-    }
+    assert(client->ioc);
 
     /* finish any pending coroutines */
     qio_channel_shutdown(client->ioc,
@@ -153,10 +151,7 @@ static int nbd_co_send_request(BlockDriverState *bs,
         rc = -EIO;
         goto err;
     }
-    if (!s->ioc) {
-        rc = -EPIPE;
-        goto err;
-    }
+    assert(s->ioc);
 
     if (qiov) {
         qio_channel_set_cork(s->ioc, true);
@@ -429,10 +424,11 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
     s->requests[i].receiving = true;
     qemu_coroutine_yield();
     s->requests[i].receiving = false;
-    if (!s->ioc || s->quit) {
+    if (s->quit) {
         error_setg(errp, "Connection closed");
         return -EIO;
     }
+    assert(s->ioc);
 
     assert(s->reply.handle == handle);
 
@@ -982,9 +978,7 @@ void nbd_client_close(BlockDriverState *bs)
     NBDClientSession *client = nbd_get_client_session(bs);
     NBDRequest request = { .type = NBD_CMD_DISC };
 
-    if (client->ioc == NULL) {
-        return;
-    }
+    assert(client->ioc);
 
     nbd_send_request(client->ioc, &request);
 
-- 
2.18.0

[Qemu-devel] [PATCH v5 6/6] block/nbd-client: rename read_reply_co to connection_co

[Vladimir Sementsov-Ogievskiy]

This coroutine will serve nbd reconnects, so, rename it to be something
more generic.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/nbd-client.h |  4 ++--
 block/nbd-client.c | 24 ++++++++++++------------
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/block/nbd-client.h b/block/nbd-client.h
index 2f047ba614..d990207a5c 100644
--- a/block/nbd-client.h
+++ b/block/nbd-client.h
@@ -20,7 +20,7 @@
 typedef struct {
     Coroutine *coroutine;
     uint64_t offset;        /* original offset of the request */
-    bool receiving;         /* waiting for read_reply_co? */
+    bool receiving;         /* waiting for connection_co? */
 } NBDClientRequest;
 
 typedef struct NBDClientSession {
@@ -30,7 +30,7 @@ typedef struct NBDClientSession {
 
     CoMutex send_mutex;
     CoQueue free_sema;
-    Coroutine *read_reply_co;
+    Coroutine *connection_co;
     int in_flight;
 
     NBDClientRequest requests[MAX_NBD_REQUESTS];
diff --git a/block/nbd-client.c b/block/nbd-client.c
index d8bf1bbb8b..d9e33751ad 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -59,7 +59,7 @@ static void nbd_teardown_connection(BlockDriverState *bs)
     qio_channel_shutdown(client->ioc,
                          QIO_CHANNEL_SHUTDOWN_BOTH,
                          NULL);
-    BDRV_POLL_WHILE(bs, client->read_reply_co);
+    BDRV_POLL_WHILE(bs, client->connection_co);
 
     nbd_client_detach_aio_context(bs);
     object_unref(OBJECT(client->sioc));
@@ -68,7 +68,7 @@ static void nbd_teardown_connection(BlockDriverState *bs)
     client->ioc = NULL;
 }
 
-static coroutine_fn void nbd_read_reply_entry(void *opaque)
+static coroutine_fn void nbd_connection_entry(void *opaque)
 {
     NBDClientSession *s = opaque;
     uint64_t i;
@@ -100,14 +100,14 @@ static coroutine_fn void nbd_read_reply_entry(void *opaque)
         }
 
         /* We're woken up again by the request itself.  Note that there
-         * is no race between yielding and reentering read_reply_co.  This
+         * is no race between yielding and reentering connection_co.  This
          * is because:
          *
          * - if the request runs on the same AioContext, it is only
          *   entered after we yield
          *
          * - if the request runs on a different AioContext, reentering
-         *   read_reply_co happens through a bottom half, which can only
+         *   connection_co happens through a bottom half, which can only
          *   run after we yield.
          */
         aio_co_wake(s->requests[i].coroutine);
@@ -116,7 +116,7 @@ static coroutine_fn void nbd_read_reply_entry(void *opaque)
 
     s->quit = true;
     nbd_recv_coroutines_wake_all(s);
-    s->read_reply_co = NULL;
+    s->connection_co = NULL;
 }
 
 static int nbd_co_send_request(BlockDriverState *bs,
@@ -420,7 +420,7 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
     }
     *request_ret = 0;
 
-    /* Wait until we're woken up by nbd_read_reply_entry.  */
+    /* Wait until we're woken up by nbd_connection_entry.  */
     s->requests[i].receiving = true;
     qemu_coroutine_yield();
     s->requests[i].receiving = false;
@@ -495,7 +495,7 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
 }
 
 /* nbd_co_receive_one_chunk
- * Read reply, wake up read_reply_co and set s->quit if needed.
+ * Read reply, wake up connection_co and set s->quit if needed.
  * Return value is a fatal error code or normal nbd reply error code
  */
 static coroutine_fn int nbd_co_receive_one_chunk(
@@ -509,15 +509,15 @@ static coroutine_fn int nbd_co_receive_one_chunk(
     if (ret < 0) {
         s->quit = true;
     } else {
-        /* For assert at loop start in nbd_read_reply_entry */
+        /* For assert at loop start in nbd_connection_entry */
         if (reply) {
             *reply = s->reply;
         }
         s->reply.handle = 0;
     }
 
-    if (s->read_reply_co) {
-        aio_co_wake(s->read_reply_co);
+    if (s->connection_co) {
+        aio_co_wake(s->connection_co);
     }
 
     return ret;
@@ -970,7 +970,7 @@ void nbd_client_attach_aio_context(BlockDriverState *bs,
 {
     NBDClientSession *client = nbd_get_client_session(bs);
     qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc), new_context);
-    aio_co_schedule(new_context, client->read_reply_co);
+    aio_co_schedule(new_context, client->connection_co);
 }
 
 void nbd_client_close(BlockDriverState *bs)
@@ -1077,7 +1077,7 @@ static int nbd_client_connect(BlockDriverState *bs,
     /* Now that we're connected, set the socket to be non-blocking and
      * kick the reply mechanism.  */
     qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
-    client->read_reply_co = qemu_coroutine_create(nbd_read_reply_entry, client);
+    client->connection_co = qemu_coroutine_create(nbd_connection_entry, client);
     nbd_client_attach_aio_context(bs, bdrv_get_aio_context(bs));
 
     logout("Established connection with NBD server\n");
-- 
2.18.0

Re: [Qemu-devel] [PATCH v5 6/6] block/nbd-client: rename read_reply_co to connection_co

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 630 bytes --]

On 2/1/19 7:01 AM, Vladimir Sementsov-Ogievskiy wrote:
> This coroutine will serve nbd reconnects, so, rename it to be something
> more generic.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> ---
>  block/nbd-client.h |  4 ++--
>  block/nbd-client.c | 24 ++++++++++++------------
>  2 files changed, 14 insertions(+), 14 deletions(-)

Trivial merge conflict with patches that recently landed; I can fix that.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [Qemu-devel] [PATCH v5 2/6] block/nbd: move connection code from block/nbd to block/nbd-client

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 956 bytes --]

On 2/1/19 7:01 AM, Vladimir Sementsov-Ogievskiy wrote:
> Keep all connection code in one file, to be able to implement reconnect
> in further patches.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
> 

> +static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
> +                                                  Error **errp)
> +{
> +    QIOChannelSocket *sioc;
> +    Error *local_err = NULL;
> +
> +    sioc = qio_channel_socket_new();
> +    qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
> +
> +    qio_channel_socket_connect_sync(sioc,
> +                                    saddr,
> +                                    &local_err);

I know it was code motion, but this fits on one line.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [Qemu-devel] [PATCH v5 0/6] NBD reconnect: prep. refactoring

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 1201 bytes --]

On 2/1/19 7:01 AM, Vladimir Sementsov-Ogievskiy wrote:
> Hi all.
> 
> Here is most of preparatory refactoring for NBD reconnect, rebased
> on master. Let's push it.

Thanks; queued for my next NBD pull request.

> 
> Sorry for a long delay in answering on v4 review and for v4 which
> I pinged a lot can't be applied on master directly :(
> 
> v5:
> 02: rebased on master, object_unref() moved to fail: block
> 05: tiny fixes in commit message [Eric]
> 
> Vladimir Sementsov-Ogievskiy (6):
>   block/nbd-client: split channel errors from export errors
>   block/nbd: move connection code from block/nbd to block/nbd-client
>   block/nbd-client: split connection from initialization
>   block/nbd-client: fix nbd_reply_chunk_iter_receive
>   block/nbd-client: don't check ioc
>   block/nbd-client: rename read_reply_co to connection_co
> 
>  block/nbd-client.h |   6 +-
>  block/nbd-client.c | 196 +++++++++++++++++++++++++++++----------------
>  block/nbd.c        |  40 +--------
>  3 files changed, 131 insertions(+), 111 deletions(-)
> 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]