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GET /api/patches/818256/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 818256,
    "url": "http://patchwork.ozlabs.org/api/patches/818256/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170925135801.144261-5-vsementsov@virtuozzo.com/",
    "project": {
        "id": 14,
        "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api",
        "name": "QEMU Development",
        "link_name": "qemu-devel",
        "list_id": "qemu-devel.nongnu.org",
        "list_email": "qemu-devel@nongnu.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": "",
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<20170925135801.144261-5-vsementsov@virtuozzo.com>",
    "list_archive_url": null,
    "date": "2017-09-25T13:57:57",
    "name": "[4/8] nbd-server: refactor simple reply sending",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "25e6f3710b1b9ff9a48fec2001d0983bcbb8346f",
    "submitter": {
        "id": 66592,
        "url": "http://patchwork.ozlabs.org/api/people/66592/?format=api",
        "name": "Vladimir Sementsov-Ogievskiy",
        "email": "vsementsov@virtuozzo.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170925135801.144261-5-vsementsov@virtuozzo.com/mbox/",
    "series": [
        {
            "id": 4967,
            "url": "http://patchwork.ozlabs.org/api/series/4967/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=4967",
            "date": "2017-09-25T13:58:01",
            "name": "nbd minimal structured read",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/4967/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/818256/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/818256/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>",
        "X-Original-To": "incoming@patchwork.ozlabs.org",
        "Delivered-To": "patchwork-incoming@bilbo.ozlabs.org",
        "Authentication-Results": "ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=<UNKNOWN>)",
        "Received": [
            "from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3y15Qn0S6Nz9tXC\n\tfor <incoming@patchwork.ozlabs.org>;\n\tTue, 26 Sep 2017 00:03:29 +1000 (AEST)",
            "from localhost ([::1]:42596 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>)\n\tid 1dwTyp-0001vy-30\n\tfor incoming@patchwork.ozlabs.org; Mon, 25 Sep 2017 10:03:27 -0400",
            "from eggs.gnu.org ([2001:4830:134:3::10]:39655)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <vsementsov@virtuozzo.com>) id 1dwTtz-0006YX-Jn\n\tfor qemu-devel@nongnu.org; Mon, 25 Sep 2017 09:58:33 -0400",
            "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <vsementsov@virtuozzo.com>) id 1dwTtw-0007E8-5R\n\tfor qemu-devel@nongnu.org; Mon, 25 Sep 2017 09:58:27 -0400",
            "from mailhub.sw.ru ([195.214.232.25]:46327 helo=relay.sw.ru)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from <vsementsov@virtuozzo.com>)\n\tid 1dwTtv-0007CS-K7\n\tfor qemu-devel@nongnu.org; Mon, 25 Sep 2017 09:58:24 -0400",
            "from kvm.sw.ru (msk-vpn.virtuozzo.com [195.214.232.6])\n\tby relay.sw.ru (8.13.4/8.13.4) with ESMTP id v8PDw1fu013085;\n\tMon, 25 Sep 2017 16:58:02 +0300 (MSK)"
        ],
        "From": "Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>",
        "To": "qemu-devel@nongnu.org, qemu-block@nongnu.org",
        "Date": "Mon, 25 Sep 2017 16:57:57 +0300",
        "Message-Id": "<20170925135801.144261-5-vsementsov@virtuozzo.com>",
        "X-Mailer": "git-send-email 2.11.1",
        "In-Reply-To": "<20170925135801.144261-1-vsementsov@virtuozzo.com>",
        "References": "<20170925135801.144261-1-vsementsov@virtuozzo.com>",
        "X-detected-operating-system": "by eggs.gnu.org: OpenBSD 3.x [fuzzy]",
        "X-Received-From": "195.214.232.25",
        "Subject": "[Qemu-devel] [PATCH 4/8] nbd-server: refactor simple reply sending",
        "X-BeenThere": "qemu-devel@nongnu.org",
        "X-Mailman-Version": "2.1.21",
        "Precedence": "list",
        "List-Id": "<qemu-devel.nongnu.org>",
        "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>",
        "List-Archive": "<http://lists.nongnu.org/archive/html/qemu-devel/>",
        "List-Post": "<mailto:qemu-devel@nongnu.org>",
        "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>",
        "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=subscribe>",
        "Cc": "kwolf@redhat.com, vsementsov@virtuozzo.com, Hmreitz@redhat.com,\n\tden@openvz.org, pbonzini@redhat.com",
        "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org",
        "Sender": "\"Qemu-devel\"\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>"
    },
    "content": "Get rid of calculating structure fields offsets by hand and set_cork,\nrename nbd_co_send_reply to nbd_co_send_simple_reply. Do not use\nNBDReply which will be upgraded in future patches to handle both simple\nand structured replies and will be used only in the client.\n\nSigned-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>\n---\n include/block/nbd.h |  6 ++++\n nbd/nbd-internal.h  |  9 +++++\n nbd/server.c        | 97 ++++++++++++++++++++++-------------------------------\n 3 files changed, 56 insertions(+), 56 deletions(-)",
    "diff": "diff --git a/include/block/nbd.h b/include/block/nbd.h\nindex 707fd37575..49008980f4 100644\n--- a/include/block/nbd.h\n+++ b/include/block/nbd.h\n@@ -63,6 +63,12 @@ struct NBDReply {\n };\n typedef struct NBDReply NBDReply;\n \n+typedef struct NBDSimpleReply {\n+    uint32_t magic;  /* NBD_SIMPLE_REPLY_MAGIC */\n+    uint32_t error;\n+    uint64_t handle;\n+} QEMU_PACKED NBDSimpleReply;\n+\n /* Transmission (export) flags: sent from server to client during handshake,\n    but describe what will happen during transmission */\n #define NBD_FLAG_HAS_FLAGS      (1 << 0)        /* Flags are there */\ndiff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h\nindex 2d6663de23..320abef296 100644\n--- a/nbd/nbd-internal.h\n+++ b/nbd/nbd-internal.h\n@@ -113,6 +113,15 @@ static inline int nbd_write(QIOChannel *ioc, const void *buffer, size_t size,\n     return qio_channel_write_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;\n }\n \n+/* nbd_writev\n+ * Writes @size bytes to @ioc. Returns 0 on success.\n+ */\n+static inline int nbd_writev(QIOChannel *ioc, const struct iovec *iov,\n+                             size_t niov, Error **errp)\n+{\n+    return qio_channel_writev_all(ioc, iov, niov, errp) < 0 ? -EIO : 0;\n+}\n+\n struct NBDTLSHandshakeData {\n     GMainLoop *loop;\n     bool complete;\ndiff --git a/nbd/server.c b/nbd/server.c\nindex a1b21a6951..57d5598e0f 100644\n--- a/nbd/server.c\n+++ b/nbd/server.c\n@@ -902,26 +902,6 @@ static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,\n     return 0;\n }\n \n-static int nbd_send_reply(QIOChannel *ioc, NBDReply *reply, Error **errp)\n-{\n-    uint8_t buf[NBD_REPLY_SIZE];\n-\n-    reply->error = system_errno_to_nbd_errno(reply->error);\n-\n-    trace_nbd_send_reply(reply->error, reply->handle);\n-\n-    /* Reply\n-       [ 0 ..  3]    magic   (NBD_SIMPLE_REPLY_MAGIC)\n-       [ 4 ..  7]    error   (0 == no error)\n-       [ 7 .. 15]    handle\n-     */\n-    stl_be_p(buf, NBD_SIMPLE_REPLY_MAGIC);\n-    stl_be_p(buf + 4, reply->error);\n-    stq_be_p(buf + 8, reply->handle);\n-\n-    return nbd_write(ioc, buf, sizeof(buf), errp);\n-}\n-\n #define MAX_NBD_REQUESTS 16\n \n void nbd_client_get(NBDClient *client)\n@@ -1208,38 +1188,51 @@ void nbd_export_close_all(void)\n     }\n }\n \n-static int nbd_co_send_reply(NBDRequestData *req, NBDReply *reply, int len,\n-                             Error **errp)\n+static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,\n+                                        unsigned niov, Error **errp)\n {\n-    NBDClient *client = req->client;\n     int ret;\n \n     g_assert(qemu_in_coroutine());\n-\n-    trace_nbd_co_send_reply(reply->handle, reply->error, len);\n-\n     qemu_co_mutex_lock(&client->send_lock);\n     client->send_coroutine = qemu_coroutine_self();\n \n-    if (!len) {\n-        ret = nbd_send_reply(client->ioc, reply, errp);\n-    } else {\n-        qio_channel_set_cork(client->ioc, true);\n-        ret = nbd_send_reply(client->ioc, reply, errp);\n-        if (ret == 0) {\n-            ret = nbd_write(client->ioc, req->data, len, errp);\n-            if (ret < 0) {\n-                ret = -EIO;\n-            }\n-        }\n-        qio_channel_set_cork(client->ioc, false);\n-    }\n+    ret = nbd_writev(client->ioc, iov, niov, errp);\n \n     client->send_coroutine = NULL;\n     qemu_co_mutex_unlock(&client->send_lock);\n+\n     return ret;\n }\n \n+static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,\n+                                       uint64_t handle)\n+{\n+    stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);\n+    stl_be_p(&reply->error, error);\n+    stq_be_p(&reply->handle, handle);\n+}\n+\n+static int nbd_co_send_simple_reply(NBDClient *client,\n+                                    uint64_t handle,\n+                                    uint32_t error,\n+                                    void *data,\n+                                    size_t size,\n+                                    Error **errp)\n+{\n+    NBDSimpleReply reply;\n+    struct iovec iov[] = {\n+        {.iov_base = &reply, .iov_len = sizeof(reply)},\n+        {.iov_base = data, .iov_len = size}\n+    };\n+\n+    trace_nbd_co_send_reply(handle, error, size);\n+\n+    set_be_simple_reply(&reply, system_errno_to_nbd_errno(error), handle);\n+\n+    return nbd_co_send_iov(client, iov, size ? 2 : 1, errp);\n+}\n+\n /* nbd_co_receive_request\n  * Collect a client request. Return 0 if request looks valid, -EIO to drop\n  * connection right away, and any other negative value to report an error to\n@@ -1331,7 +1324,6 @@ static coroutine_fn void nbd_trip(void *opaque)\n     NBDExport *exp = client->exp;\n     NBDRequestData *req;\n     NBDRequest request = { 0 };    /* GCC thinks it can be used uninitialized */\n-    NBDReply reply;\n     int ret;\n     int flags;\n     int reply_data_len = 0;\n@@ -1351,11 +1343,7 @@ static coroutine_fn void nbd_trip(void *opaque)\n         goto disconnect;\n     }\n \n-    reply.handle = request.handle;\n-    reply.error = 0;\n-\n     if (ret < 0) {\n-        reply.error = -ret;\n         goto reply;\n     }\n \n@@ -1374,7 +1362,6 @@ static coroutine_fn void nbd_trip(void *opaque)\n             ret = blk_co_flush(exp->blk);\n             if (ret < 0) {\n                 error_setg_errno(&local_err, -ret, \"flush failed\");\n-                reply.error = -ret;\n                 break;\n             }\n         }\n@@ -1383,7 +1370,6 @@ static coroutine_fn void nbd_trip(void *opaque)\n                         req->data, request.len);\n         if (ret < 0) {\n             error_setg_errno(&local_err, -ret, \"reading from file failed\");\n-            reply.error = -ret;\n             break;\n         }\n \n@@ -1392,7 +1378,7 @@ static coroutine_fn void nbd_trip(void *opaque)\n         break;\n     case NBD_CMD_WRITE:\n         if (exp->nbdflags & NBD_FLAG_READ_ONLY) {\n-            reply.error = EROFS;\n+            ret = -EROFS;\n             break;\n         }\n \n@@ -1404,14 +1390,13 @@ static coroutine_fn void nbd_trip(void *opaque)\n                          req->data, request.len, flags);\n         if (ret < 0) {\n             error_setg_errno(&local_err, -ret, \"writing to file failed\");\n-            reply.error = -ret;\n         }\n \n         break;\n     case NBD_CMD_WRITE_ZEROES:\n         if (exp->nbdflags & NBD_FLAG_READ_ONLY) {\n             error_setg(&local_err, \"Server is read-only, return error\");\n-            reply.error = EROFS;\n+            ret = -EROFS;\n             break;\n         }\n \n@@ -1426,7 +1411,6 @@ static coroutine_fn void nbd_trip(void *opaque)\n                                 request.len, flags);\n         if (ret < 0) {\n             error_setg_errno(&local_err, -ret, \"writing to file failed\");\n-            reply.error = -ret;\n         }\n \n         break;\n@@ -1438,7 +1422,6 @@ static coroutine_fn void nbd_trip(void *opaque)\n         ret = blk_co_flush(exp->blk);\n         if (ret < 0) {\n             error_setg_errno(&local_err, -ret, \"flush failed\");\n-            reply.error = -ret;\n         }\n \n         break;\n@@ -1447,25 +1430,27 @@ static coroutine_fn void nbd_trip(void *opaque)\n                               request.len);\n         if (ret < 0) {\n             error_setg_errno(&local_err, -ret, \"discard failed\");\n-            reply.error = -ret;\n         }\n \n         break;\n     default:\n         error_setg(&local_err, \"invalid request type (%\" PRIu32 \") received\",\n                    request.type);\n-        reply.error = EINVAL;\n+        ret = -EINVAL;\n     }\n \n reply:\n     if (local_err) {\n-        /* If we are here local_err is not fatal error, already stored in\n-         * reply.error */\n+        /* If we are here local_err is not fatal error, which should be sent\n+         * to client. */\n         error_report_err(local_err);\n         local_err = NULL;\n     }\n \n-    if (nbd_co_send_reply(req, &reply, reply_data_len, &local_err) < 0) {\n+    if (nbd_co_send_simple_reply(req->client, request.handle,\n+                                 ret < 0 ? -ret : 0,\n+                                 req->data, reply_data_len, &local_err) < 0)\n+    {\n         error_prepend(&local_err, \"Failed to send reply: \");\n         goto disconnect;\n     }\n",
    "prefixes": [
        "4/8"
    ]
}