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-rw-r--r--nbd/client.c79
-rw-r--r--nbd/common.c17
-rw-r--r--nbd/server.c224
-rw-r--r--nbd/trace-events22
4 files changed, 201 insertions, 141 deletions
diff --git a/nbd/client.c b/nbd/client.c
index 30d5383cb1..479208d5d9 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2016-2019 Red Hat, Inc.
+ *  Copyright Red Hat
  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
  *
  *  Network Block Device Client Side
@@ -650,19 +650,20 @@ static int nbd_send_meta_query(QIOChannel *ioc, uint32_t opt,
                                Error **errp)
 {
     int ret;
-    uint32_t export_len = strlen(export);
+    uint32_t export_len;
     uint32_t queries = !!query;
     uint32_t query_len = 0;
     uint32_t data_len;
     char *data;
     char *p;
 
+    assert(strnlen(export, NBD_MAX_STRING_SIZE + 1) <= NBD_MAX_STRING_SIZE);
+    export_len = strlen(export);
     data_len = sizeof(export_len) + export_len + sizeof(queries);
-    assert(export_len <= NBD_MAX_STRING_SIZE);
     if (query) {
+        assert(strnlen(query, NBD_MAX_STRING_SIZE + 1) <= NBD_MAX_STRING_SIZE);
         query_len = strlen(query);
         data_len += sizeof(query_len) + query_len;
-        assert(query_len <= NBD_MAX_STRING_SIZE);
     } else {
         assert(opt == NBD_OPT_LIST_META_CONTEXT);
     }
@@ -874,10 +875,7 @@ static int nbd_list_meta_contexts(QIOChannel *ioc,
  * Start the handshake to the server.  After a positive return, the server
  * is ready to accept additional NBD_OPT requests.
  * Returns: negative errno: failure talking to server
- *          0: server is oldstyle, must call nbd_negotiate_finish_oldstyle
- *          1: server is newstyle, but can only accept EXPORT_NAME
- *          2: server is newstyle, but lacks structured replies
- *          3: server is newstyle and set up for structured replies
+ *          non-negative: enum NBDMode describing server abilities
  */
 static int nbd_start_negotiate(AioContext *aio_context, QIOChannel *ioc,
                                QCryptoTLSCreds *tlscreds,
@@ -968,16 +966,16 @@ static int nbd_start_negotiate(AioContext *aio_context, QIOChannel *ioc,
                     return -EINVAL;
                 }
             }
-            return 2 + result;
+            return result ? NBD_MODE_STRUCTURED : NBD_MODE_SIMPLE;
         } else {
-            return 1;
+            return NBD_MODE_EXPORT_NAME;
         }
     } else if (magic == NBD_CLIENT_MAGIC) {
         if (tlscreds) {
             error_setg(errp, "Server does not support STARTTLS");
             return -EINVAL;
         }
-        return 0;
+        return NBD_MODE_OLDSTYLE;
     } else {
         error_setg(errp, "Bad server magic received: 0x%" PRIx64, magic);
         return -EINVAL;
@@ -1031,6 +1029,9 @@ int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
 
     result = nbd_start_negotiate(aio_context, ioc, tlscreds, hostname, outioc,
                                  info->structured_reply, &zeroes, errp);
+    if (result < 0) {
+        return result;
+    }
 
     info->structured_reply = false;
     info->base_allocation = false;
@@ -1038,8 +1039,8 @@ int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
         ioc = *outioc;
     }
 
-    switch (result) {
-    case 3: /* newstyle, with structured replies */
+    switch ((NBDMode)result) {
+    case NBD_MODE_STRUCTURED:
         info->structured_reply = true;
         if (base_allocation) {
             result = nbd_negotiate_simple_meta_context(ioc, info, errp);
@@ -1049,7 +1050,7 @@ int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
             info->base_allocation = result == 1;
         }
         /* fall through */
-    case 2: /* newstyle, try OPT_GO */
+    case NBD_MODE_SIMPLE:
         /* Try NBD_OPT_GO first - if it works, we are done (it
          * also gives us a good message if the server requires
          * TLS).  If it is not available, fall back to
@@ -1072,7 +1073,7 @@ int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
             return -EINVAL;
         }
         /* fall through */
-    case 1: /* newstyle, but limited to EXPORT_NAME */
+    case NBD_MODE_EXPORT_NAME:
         /* write the export name request */
         if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, info->name,
                                     errp) < 0) {
@@ -1088,7 +1089,7 @@ int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
             return -EINVAL;
         }
         break;
-    case 0: /* oldstyle, parse length and flags */
+    case NBD_MODE_OLDSTYLE:
         if (*info->name) {
             error_setg(errp, "Server does not support non-empty export names");
             return -EINVAL;
@@ -1098,7 +1099,7 @@ int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
         }
         break;
     default:
-        return result;
+        g_assert_not_reached();
     }
 
     trace_nbd_receive_negotiate_size_flags(info->size, info->flags);
@@ -1154,10 +1155,13 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
     if (tlscreds && sioc) {
         ioc = sioc;
     }
+    if (result < 0) {
+        goto out;
+    }
 
-    switch (result) {
-    case 2:
-    case 3:
+    switch ((NBDMode)result) {
+    case NBD_MODE_SIMPLE:
+    case NBD_MODE_STRUCTURED:
         /* newstyle - use NBD_OPT_LIST to populate array, then try
          * NBD_OPT_INFO on each array member. If structured replies
          * are enabled, also try NBD_OPT_LIST_META_CONTEXT. */
@@ -1178,7 +1182,7 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
             memset(&array[count - 1], 0, sizeof(*array));
             array[count - 1].name = name;
             array[count - 1].description = desc;
-            array[count - 1].structured_reply = result == 3;
+            array[count - 1].structured_reply = result == NBD_MODE_STRUCTURED;
         }
 
         for (i = 0; i < count; i++) {
@@ -1194,7 +1198,7 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
                 break;
             }
 
-            if (result == 3 &&
+            if (result == NBD_MODE_STRUCTURED &&
                 nbd_list_meta_contexts(ioc, &array[i], errp) < 0) {
                 goto out;
             }
@@ -1203,11 +1207,12 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
         /* Send NBD_OPT_ABORT as a courtesy before hanging up */
         nbd_send_opt_abort(ioc);
         break;
-    case 1: /* newstyle, but limited to EXPORT_NAME */
+    case NBD_MODE_EXPORT_NAME:
         error_setg(errp, "Server does not support export lists");
         /* We can't even send NBD_OPT_ABORT, so merely hang up */
         goto out;
-    case 0: /* oldstyle, parse length and flags */
+    case NBD_MODE_OLDSTYLE:
+        /* Lone export name is implied, but we can parse length and flags */
         array = g_new0(NBDExportInfo, 1);
         array->name = g_strdup("");
         count = 1;
@@ -1225,7 +1230,7 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
         }
         break;
     default:
-        goto out;
+        g_assert_not_reached();
     }
 
     *info = array;
@@ -1349,14 +1354,14 @@ int nbd_send_request(QIOChannel *ioc, NBDRequest *request)
 {
     uint8_t buf[NBD_REQUEST_SIZE];
 
-    trace_nbd_send_request(request->from, request->len, request->handle,
+    trace_nbd_send_request(request->from, request->len, request->cookie,
                            request->flags, request->type,
                            nbd_cmd_lookup(request->type));
 
     stl_be_p(buf, NBD_REQUEST_MAGIC);
     stw_be_p(buf + 4, request->flags);
     stw_be_p(buf + 6, request->type);
-    stq_be_p(buf + 8, request->handle);
+    stq_be_p(buf + 8, request->cookie);
     stq_be_p(buf + 16, request->from);
     stl_be_p(buf + 24, request->len);
 
@@ -1382,7 +1387,7 @@ static int nbd_receive_simple_reply(QIOChannel *ioc, NBDSimpleReply *reply,
     }
 
     reply->error = be32_to_cpu(reply->error);
-    reply->handle = be64_to_cpu(reply->handle);
+    reply->cookie = be64_to_cpu(reply->cookie);
 
     return 0;
 }
@@ -1409,9 +1414,21 @@ static int nbd_receive_structured_reply_chunk(QIOChannel *ioc,
 
     chunk->flags = be16_to_cpu(chunk->flags);
     chunk->type = be16_to_cpu(chunk->type);
-    chunk->handle = be64_to_cpu(chunk->handle);
+    chunk->cookie = be64_to_cpu(chunk->cookie);
     chunk->length = be32_to_cpu(chunk->length);
 
+    /*
+     * Because we use BLOCK_STATUS with REQ_ONE, and cap READ requests
+     * at 32M, no valid server should send us payload larger than
+     * this.  Even if we stopped using REQ_ONE, sane servers will cap
+     * the number of extents they return for block status.
+     */
+    if (chunk->length > NBD_MAX_BUFFER_SIZE + sizeof(NBDStructuredReadData)) {
+        error_setg(errp, "server chunk %" PRIu32 " (%s) payload is too long",
+                   chunk->type, nbd_rep_lookup(chunk->type));
+        return -EINVAL;
+    }
+
     return 0;
 }
 
@@ -1486,7 +1503,7 @@ int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc,
         }
         trace_nbd_receive_simple_reply(reply->simple.error,
                                        nbd_err_lookup(reply->simple.error),
-                                       reply->handle);
+                                       reply->cookie);
         break;
     case NBD_STRUCTURED_REPLY_MAGIC:
         ret = nbd_receive_structured_reply_chunk(ioc, &reply->structured, errp);
@@ -1496,7 +1513,7 @@ int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc,
         type = nbd_reply_type_lookup(reply->structured.type);
         trace_nbd_receive_structured_reply_chunk(reply->structured.flags,
                                                  reply->structured.type, type,
-                                                 reply->structured.handle,
+                                                 reply->structured.cookie,
                                                  reply->structured.length);
         break;
     default:
diff --git a/nbd/common.c b/nbd/common.c
index ddfe7d1183..989fbe54a1 100644
--- a/nbd/common.c
+++ b/nbd/common.c
@@ -248,3 +248,20 @@ int nbd_errno_to_system_errno(int err)
     }
     return ret;
 }
+
+
+const char *nbd_mode_lookup(NBDMode mode)
+{
+    switch (mode) {
+    case NBD_MODE_OLDSTYLE:
+        return "oldstyle";
+    case NBD_MODE_EXPORT_NAME:
+        return "export name only";
+    case NBD_MODE_SIMPLE:
+        return "simple headers";
+    case NBD_MODE_STRUCTURED:
+        return "structured replies";
+    default:
+        return "<unknown>";
+    }
+}
diff --git a/nbd/server.c b/nbd/server.c
index febe001a39..8486b64b15 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2016-2022 Red Hat, Inc.
+ *  Copyright Red Hat
  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
  *
  *  Network Block Device Server Side
@@ -1428,7 +1428,7 @@ static int coroutine_fn nbd_receive_request(NBDClient *client, NBDRequest *reque
        [ 0 ..  3]   magic   (NBD_REQUEST_MAGIC)
        [ 4 ..  5]   flags   (NBD_CMD_FLAG_FUA, ...)
        [ 6 ..  7]   type    (NBD_CMD_READ, ...)
-       [ 8 .. 15]   handle
+       [ 8 .. 15]   cookie
        [16 .. 23]   from
        [24 .. 27]   len
      */
@@ -1436,7 +1436,7 @@ static int coroutine_fn nbd_receive_request(NBDClient *client, NBDRequest *reque
     magic = ldl_be_p(buf);
     request->flags  = lduw_be_p(buf + 4);
     request->type   = lduw_be_p(buf + 6);
-    request->handle = ldq_be_p(buf + 8);
+    request->cookie = ldq_be_p(buf + 8);
     request->from   = ldq_be_p(buf + 16);
     request->len    = ldl_be_p(buf + 24);
 
@@ -1885,15 +1885,15 @@ static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
 }
 
 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
-                                       uint64_t handle)
+                                       uint64_t cookie)
 {
     stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
     stl_be_p(&reply->error, error);
-    stq_be_p(&reply->handle, handle);
+    stq_be_p(&reply->cookie, cookie);
 }
 
 static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client,
-                                                 uint64_t handle,
+                                                 NBDRequest *request,
                                                  uint32_t error,
                                                  void *data,
                                                  size_t len,
@@ -1906,84 +1906,108 @@ static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client,
         {.iov_base = data, .iov_len = len}
     };
 
-    trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err),
-                                   len);
-    set_be_simple_reply(&reply, nbd_err, handle);
+    assert(!len || !nbd_err);
+    assert(!client->structured_reply || request->type != NBD_CMD_READ);
+    trace_nbd_co_send_simple_reply(request->cookie, nbd_err,
+                                   nbd_err_lookup(nbd_err), len);
+    set_be_simple_reply(&reply, nbd_err, request->cookie);
 
-    return nbd_co_send_iov(client, iov, len ? 2 : 1, errp);
+    return nbd_co_send_iov(client, iov, 2, errp);
 }
 
-static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags,
-                                uint16_t type, uint64_t handle, uint32_t length)
+/*
+ * Prepare the header of a reply chunk for network transmission.
+ *
+ * On input, @iov is partially initialized: iov[0].iov_base must point
+ * to an uninitialized NBDReply, while the remaining @niov elements
+ * (if any) must be ready for transmission.  This function then
+ * populates iov[0] for transmission.
+ */
+static inline void set_be_chunk(NBDClient *client, struct iovec *iov,
+                                size_t niov, uint16_t flags, uint16_t type,
+                                NBDRequest *request)
 {
+    /* TODO - handle structured vs. extended replies */
+    NBDStructuredReplyChunk *chunk = iov->iov_base;
+    size_t i, length = 0;
+
+    for (i = 1; i < niov; i++) {
+        length += iov[i].iov_len;
+    }
+    assert(length <= NBD_MAX_BUFFER_SIZE + sizeof(NBDStructuredReadData));
+
+    iov[0].iov_len = sizeof(*chunk);
     stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);
     stw_be_p(&chunk->flags, flags);
     stw_be_p(&chunk->type, type);
-    stq_be_p(&chunk->handle, handle);
+    stq_be_p(&chunk->cookie, request->cookie);
     stl_be_p(&chunk->length, length);
 }
 
-static int coroutine_fn nbd_co_send_structured_done(NBDClient *client,
-                                                    uint64_t handle,
-                                                    Error **errp)
+static int coroutine_fn nbd_co_send_chunk_done(NBDClient *client,
+                                               NBDRequest *request,
+                                               Error **errp)
 {
-    NBDStructuredReplyChunk chunk;
+    NBDReply hdr;
     struct iovec iov[] = {
-        {.iov_base = &chunk, .iov_len = sizeof(chunk)},
+        {.iov_base = &hdr},
     };
 
-    trace_nbd_co_send_structured_done(handle);
-    set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0);
-
+    trace_nbd_co_send_chunk_done(request->cookie);
+    set_be_chunk(client, iov, 1, NBD_REPLY_FLAG_DONE,
+                 NBD_REPLY_TYPE_NONE, request);
     return nbd_co_send_iov(client, iov, 1, errp);
 }
 
-static int coroutine_fn nbd_co_send_structured_read(NBDClient *client,
-                                                    uint64_t handle,
-                                                    uint64_t offset,
-                                                    void *data,
-                                                    size_t size,
-                                                    bool final,
-                                                    Error **errp)
+static int coroutine_fn nbd_co_send_chunk_read(NBDClient *client,
+                                               NBDRequest *request,
+                                               uint64_t offset,
+                                               void *data,
+                                               size_t size,
+                                               bool final,
+                                               Error **errp)
 {
+    NBDReply hdr;
     NBDStructuredReadData chunk;
     struct iovec iov[] = {
+        {.iov_base = &hdr},
         {.iov_base = &chunk, .iov_len = sizeof(chunk)},
         {.iov_base = data, .iov_len = size}
     };
 
     assert(size);
-    trace_nbd_co_send_structured_read(handle, offset, data, size);
-    set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
-                 NBD_REPLY_TYPE_OFFSET_DATA, handle,
-                 sizeof(chunk) - sizeof(chunk.h) + size);
+    trace_nbd_co_send_chunk_read(request->cookie, offset, data, size);
+    set_be_chunk(client, iov, 3, final ? NBD_REPLY_FLAG_DONE : 0,
+                 NBD_REPLY_TYPE_OFFSET_DATA, request);
     stq_be_p(&chunk.offset, offset);
 
-    return nbd_co_send_iov(client, iov, 2, errp);
+    return nbd_co_send_iov(client, iov, 3, errp);
 }
-
-static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,
-                                                     uint64_t handle,
-                                                     uint32_t error,
-                                                     const char *msg,
-                                                     Error **errp)
+/*ebb*/
+static int coroutine_fn nbd_co_send_chunk_error(NBDClient *client,
+                                                NBDRequest *request,
+                                                uint32_t error,
+                                                const char *msg,
+                                                Error **errp)
 {
+    NBDReply hdr;
     NBDStructuredError chunk;
     int nbd_err = system_errno_to_nbd_errno(error);
     struct iovec iov[] = {
+        {.iov_base = &hdr},
         {.iov_base = &chunk, .iov_len = sizeof(chunk)},
         {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
     };
 
     assert(nbd_err);
-    trace_nbd_co_send_structured_error(handle, nbd_err,
-                                       nbd_err_lookup(nbd_err), msg ? msg : "");
-    set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle,
-                 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
+    trace_nbd_co_send_chunk_error(request->cookie, nbd_err,
+                                  nbd_err_lookup(nbd_err), msg ? msg : "");
+    set_be_chunk(client, iov, 3, NBD_REPLY_FLAG_DONE,
+                 NBD_REPLY_TYPE_ERROR, request);
     stl_be_p(&chunk.error, nbd_err);
-    stw_be_p(&chunk.message_length, iov[1].iov_len);
+    stw_be_p(&chunk.message_length, iov[2].iov_len);
 
-    return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);
+    return nbd_co_send_iov(client, iov, 3, errp);
 }
 
 /* Do a sparse read and send the structured reply to the client.
@@ -1991,7 +2015,7 @@ static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,
  * reported to the client, at which point this function succeeds.
  */
 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
-                                                uint64_t handle,
+                                                NBDRequest *request,
                                                 uint64_t offset,
                                                 uint8_t *data,
                                                 size_t size,
@@ -2013,27 +2037,28 @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
             char *msg = g_strdup_printf("unable to check for holes: %s",
                                         strerror(-status));
 
-            ret = nbd_co_send_structured_error(client, handle, -status, msg,
-                                               errp);
+            ret = nbd_co_send_chunk_error(client, request, -status, msg, errp);
             g_free(msg);
             return ret;
         }
         assert(pnum && pnum <= size - progress);
         final = progress + pnum == size;
         if (status & BDRV_BLOCK_ZERO) {
+            NBDReply hdr;
             NBDStructuredReadHole chunk;
             struct iovec iov[] = {
+                {.iov_base = &hdr},
                 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
             };
 
-            trace_nbd_co_send_structured_read_hole(handle, offset + progress,
-                                                   pnum);
-            set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
-                         NBD_REPLY_TYPE_OFFSET_HOLE,
-                         handle, sizeof(chunk) - sizeof(chunk.h));
+            trace_nbd_co_send_chunk_read_hole(request->cookie,
+                                              offset + progress, pnum);
+            set_be_chunk(client, iov, 2,
+                         final ? NBD_REPLY_FLAG_DONE : 0,
+                         NBD_REPLY_TYPE_OFFSET_HOLE, request);
             stq_be_p(&chunk.offset, offset + progress);
             stl_be_p(&chunk.length, pnum);
-            ret = nbd_co_send_iov(client, iov, 1, errp);
+            ret = nbd_co_send_iov(client, iov, 2, errp);
         } else {
             ret = blk_co_pread(exp->common.blk, offset + progress, pnum,
                                data + progress, 0);
@@ -2041,9 +2066,8 @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
                 error_setg_errno(errp, -ret, "reading from file failed");
                 break;
             }
-            ret = nbd_co_send_structured_read(client, handle, offset + progress,
-                                              data + progress, pnum, final,
-                                              errp);
+            ret = nbd_co_send_chunk_read(client, request, offset + progress,
+                                         data + progress, pnum, final, errp);
         }
 
         if (ret < 0) {
@@ -2196,30 +2220,31 @@ static int coroutine_fn blockalloc_to_extents(BlockBackend *blk,
  * @last controls whether NBD_REPLY_FLAG_DONE is sent.
  */
 static int coroutine_fn
-nbd_co_send_extents(NBDClient *client, uint64_t handle, NBDExtentArray *ea,
+nbd_co_send_extents(NBDClient *client, NBDRequest *request, NBDExtentArray *ea,
                     bool last, uint32_t context_id, Error **errp)
 {
+    NBDReply hdr;
     NBDStructuredMeta chunk;
     struct iovec iov[] = {
+        {.iov_base = &hdr},
         {.iov_base = &chunk, .iov_len = sizeof(chunk)},
         {.iov_base = ea->extents, .iov_len = ea->count * sizeof(ea->extents[0])}
     };
 
     nbd_extent_array_convert_to_be(ea);
 
-    trace_nbd_co_send_extents(handle, ea->count, context_id, ea->total_length,
-                              last);
-    set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0,
-                 NBD_REPLY_TYPE_BLOCK_STATUS,
-                 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
+    trace_nbd_co_send_extents(request->cookie, ea->count, context_id,
+                              ea->total_length, last);
+    set_be_chunk(client, iov, 3, last ? NBD_REPLY_FLAG_DONE : 0,
+                 NBD_REPLY_TYPE_BLOCK_STATUS, request);
     stl_be_p(&chunk.context_id, context_id);
 
-    return nbd_co_send_iov(client, iov, 2, errp);
+    return nbd_co_send_iov(client, iov, 3, errp);
 }
 
 /* Get block status from the exported device and send it to the client */
 static int
-coroutine_fn nbd_co_send_block_status(NBDClient *client, uint64_t handle,
+coroutine_fn nbd_co_send_block_status(NBDClient *client, NBDRequest *request,
                                       BlockBackend *blk, uint64_t offset,
                                       uint32_t length, bool dont_fragment,
                                       bool last, uint32_t context_id,
@@ -2235,11 +2260,11 @@ coroutine_fn nbd_co_send_block_status(NBDClient *client, uint64_t handle,
         ret = blockalloc_to_extents(blk, offset, length, ea);
     }
     if (ret < 0) {
-        return nbd_co_send_structured_error(
-                client, handle, -ret, "can't get block status", errp);
+        return nbd_co_send_chunk_error(client, request, -ret,
+                                       "can't get block status", errp);
     }
 
-    return nbd_co_send_extents(client, handle, ea, last, context_id, errp);
+    return nbd_co_send_extents(client, request, ea, last, context_id, errp);
 }
 
 /* Populate @ea from a dirty bitmap. */
@@ -2274,17 +2299,20 @@ static void bitmap_to_extents(BdrvDirtyBitmap *bitmap,
     bdrv_dirty_bitmap_unlock(bitmap);
 }
 
-static int coroutine_fn nbd_co_send_bitmap(NBDClient *client, uint64_t handle,
-                                           BdrvDirtyBitmap *bitmap, uint64_t offset,
-                                           uint32_t length, bool dont_fragment, bool last,
-                                           uint32_t context_id, Error **errp)
+static int coroutine_fn nbd_co_send_bitmap(NBDClient *client,
+                                           NBDRequest *request,
+                                           BdrvDirtyBitmap *bitmap,
+                                           uint64_t offset,
+                                           uint32_t length, bool dont_fragment,
+                                           bool last, uint32_t context_id,
+                                           Error **errp)
 {
     unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
     g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents);
 
     bitmap_to_extents(bitmap, offset, length, ea);
 
-    return nbd_co_send_extents(client, handle, ea, last, context_id, errp);
+    return nbd_co_send_extents(client, request, ea, last, context_id, errp);
 }
 
 /* nbd_co_receive_request
@@ -2308,7 +2336,7 @@ static int coroutine_fn nbd_co_receive_request(NBDRequestData *req, NBDRequest *
         return ret;
     }
 
-    trace_nbd_co_receive_request_decode_type(request->handle, request->type,
+    trace_nbd_co_receive_request_decode_type(request->cookie, request->type,
                                              nbd_cmd_lookup(request->type));
 
     if (request->type != NBD_CMD_WRITE) {
@@ -2349,7 +2377,7 @@ static int coroutine_fn nbd_co_receive_request(NBDRequestData *req, NBDRequest *
         }
         req->complete = true;
 
-        trace_nbd_co_receive_request_payload_received(request->handle,
+        trace_nbd_co_receive_request_payload_received(request->cookie,
                                                       request->len);
     }
 
@@ -2402,16 +2430,15 @@ static int coroutine_fn nbd_co_receive_request(NBDRequestData *req, NBDRequest *
  * Returns 0 if connection is still live, -errno on failure to talk to client
  */
 static coroutine_fn int nbd_send_generic_reply(NBDClient *client,
-                                               uint64_t handle,
+                                               NBDRequest *request,
                                                int ret,
                                                const char *error_msg,
                                                Error **errp)
 {
     if (client->structured_reply && ret < 0) {
-        return nbd_co_send_structured_error(client, handle, -ret, error_msg,
-                                            errp);
+        return nbd_co_send_chunk_error(client, request, -ret, error_msg, errp);
     } else {
-        return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0,
+        return nbd_co_send_simple_reply(client, request, ret < 0 ? -ret : 0,
                                         NULL, 0, errp);
     }
 }
@@ -2431,7 +2458,7 @@ static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
     if (request->flags & NBD_CMD_FLAG_FUA) {
         ret = blk_co_flush(exp->common.blk);
         if (ret < 0) {
-            return nbd_send_generic_reply(client, request->handle, ret,
+            return nbd_send_generic_reply(client, request, ret,
                                           "flush failed", errp);
         }
     }
@@ -2439,26 +2466,25 @@ static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
     if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) &&
         request->len)
     {
-        return nbd_co_send_sparse_read(client, request->handle, request->from,
+        return nbd_co_send_sparse_read(client, request, request->from,
                                        data, request->len, errp);
     }
 
     ret = blk_co_pread(exp->common.blk, request->from, request->len, data, 0);
     if (ret < 0) {
-        return nbd_send_generic_reply(client, request->handle, ret,
+        return nbd_send_generic_reply(client, request, ret,
                                       "reading from file failed", errp);
     }
 
     if (client->structured_reply) {
         if (request->len) {
-            return nbd_co_send_structured_read(client, request->handle,
-                                               request->from, data,
-                                               request->len, true, errp);
+            return nbd_co_send_chunk_read(client, request, request->from, data,
+                                          request->len, true, errp);
         } else {
-            return nbd_co_send_structured_done(client, request->handle, errp);
+            return nbd_co_send_chunk_done(client, request, errp);
         }
     } else {
-        return nbd_co_send_simple_reply(client, request->handle, 0,
+        return nbd_co_send_simple_reply(client, request, 0,
                                         data, request->len, errp);
     }
 }
@@ -2481,7 +2507,7 @@ static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request,
     ret = blk_co_preadv(exp->common.blk, request->from, request->len,
                         NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH);
 
-    return nbd_send_generic_reply(client, request->handle, ret,
+    return nbd_send_generic_reply(client, request, ret,
                                   "caching data failed", errp);
 }
 
@@ -2512,7 +2538,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
         }
         ret = blk_co_pwrite(exp->common.blk, request->from, request->len, data,
                             flags);
-        return nbd_send_generic_reply(client, request->handle, ret,
+        return nbd_send_generic_reply(client, request, ret,
                                       "writing to file failed", errp);
 
     case NBD_CMD_WRITE_ZEROES:
@@ -2528,7 +2554,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
         }
         ret = blk_co_pwrite_zeroes(exp->common.blk, request->from, request->len,
                                    flags);
-        return nbd_send_generic_reply(client, request->handle, ret,
+        return nbd_send_generic_reply(client, request, ret,
                                       "writing to file failed", errp);
 
     case NBD_CMD_DISC:
@@ -2537,7 +2563,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
 
     case NBD_CMD_FLUSH:
         ret = blk_co_flush(exp->common.blk);
-        return nbd_send_generic_reply(client, request->handle, ret,
+        return nbd_send_generic_reply(client, request, ret,
                                       "flush failed", errp);
 
     case NBD_CMD_TRIM:
@@ -2545,12 +2571,12 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
         if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) {
             ret = blk_co_flush(exp->common.blk);
         }
-        return nbd_send_generic_reply(client, request->handle, ret,
+        return nbd_send_generic_reply(client, request, ret,
                                       "discard failed", errp);
 
     case NBD_CMD_BLOCK_STATUS:
         if (!request->len) {
-            return nbd_send_generic_reply(client, request->handle, -EINVAL,
+            return nbd_send_generic_reply(client, request, -EINVAL,
                                           "need non-zero length", errp);
         }
         if (client->export_meta.count) {
@@ -2558,7 +2584,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
             int contexts_remaining = client->export_meta.count;
 
             if (client->export_meta.base_allocation) {
-                ret = nbd_co_send_block_status(client, request->handle,
+                ret = nbd_co_send_block_status(client, request,
                                                exp->common.blk,
                                                request->from,
                                                request->len, dont_fragment,
@@ -2571,7 +2597,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
             }
 
             if (client->export_meta.allocation_depth) {
-                ret = nbd_co_send_block_status(client, request->handle,
+                ret = nbd_co_send_block_status(client, request,
                                                exp->common.blk,
                                                request->from, request->len,
                                                dont_fragment,
@@ -2587,7 +2613,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
                 if (!client->export_meta.bitmaps[i]) {
                     continue;
                 }
-                ret = nbd_co_send_bitmap(client, request->handle,
+                ret = nbd_co_send_bitmap(client, request,
                                          client->exp->export_bitmaps[i],
                                          request->from, request->len,
                                          dont_fragment, !--contexts_remaining,
@@ -2601,7 +2627,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
 
             return 0;
         } else {
-            return nbd_send_generic_reply(client, request->handle, -EINVAL,
+            return nbd_send_generic_reply(client, request, -EINVAL,
                                           "CMD_BLOCK_STATUS not negotiated",
                                           errp);
         }
@@ -2609,7 +2635,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
     default:
         msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
                               request->type);
-        ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg,
+        ret = nbd_send_generic_reply(client, request, -EINVAL, msg,
                                      errp);
         g_free(msg);
         return ret;
@@ -2672,7 +2698,7 @@ static coroutine_fn void nbd_trip(void *opaque)
         Error *export_err = local_err;
 
         local_err = NULL;
-        ret = nbd_send_generic_reply(client, request.handle, -EINVAL,
+        ret = nbd_send_generic_reply(client, &request, -EINVAL,
                                      error_get_pretty(export_err), &local_err);
         error_free(export_err);
     } else {
diff --git a/nbd/trace-events b/nbd/trace-events
index b7032ca277..f19a4d0db3 100644
--- a/nbd/trace-events
+++ b/nbd/trace-events
@@ -31,9 +31,9 @@ nbd_client_loop(void) "Doing NBD loop"
 nbd_client_loop_ret(int ret, const char *error) "NBD loop returned %d: %s"
 nbd_client_clear_queue(void) "Clearing NBD queue"
 nbd_client_clear_socket(void) "Clearing NBD socket"
-nbd_send_request(uint64_t from, uint32_t len, uint64_t handle, uint16_t flags, uint16_t type, const char *name) "Sending request to server: { .from = %" PRIu64", .len = %" PRIu32 ", .handle = %" PRIu64 ", .flags = 0x%" PRIx16 ", .type = %" PRIu16 " (%s) }"
-nbd_receive_simple_reply(int32_t error, const char *errname, uint64_t handle) "Got simple reply: { .error = %" PRId32 " (%s), handle = %" PRIu64" }"
-nbd_receive_structured_reply_chunk(uint16_t flags, uint16_t type, const char *name, uint64_t handle, uint32_t length) "Got structured reply chunk: { flags = 0x%" PRIx16 ", type = %d (%s), handle = %" PRIu64 ", length = %" PRIu32 " }"
+nbd_send_request(uint64_t from, uint32_t len, uint64_t cookie, uint16_t flags, uint16_t type, const char *name) "Sending request to server: { .from = %" PRIu64", .len = %" PRIu32 ", .cookie = %" PRIu64 ", .flags = 0x%" PRIx16 ", .type = %" PRIu16 " (%s) }"
+nbd_receive_simple_reply(int32_t error, const char *errname, uint64_t cookie) "Got simple reply: { .error = %" PRId32 " (%s), cookie = %" PRIu64" }"
+nbd_receive_structured_reply_chunk(uint16_t flags, uint16_t type, const char *name, uint64_t cookie, uint32_t length) "Got structured reply chunk: { flags = 0x%" PRIx16 ", type = %d (%s), cookie = %" PRIu64 ", length = %" PRIu32 " }"
 
 # common.c
 nbd_unknown_error(int err) "Squashing unexpected error %d to EINVAL"
@@ -63,14 +63,14 @@ nbd_negotiate_success(void) "Negotiation succeeded"
 nbd_receive_request(uint32_t magic, uint16_t flags, uint16_t type, uint64_t from, uint32_t len) "Got request: { magic = 0x%" PRIx32 ", .flags = 0x%" PRIx16 ", .type = 0x%" PRIx16 ", from = %" PRIu64 ", len = %" PRIu32 " }"
 nbd_blk_aio_attached(const char *name, void *ctx) "Export %s: Attaching clients to AIO context %p"
 nbd_blk_aio_detach(const char *name, void *ctx) "Export %s: Detaching clients from AIO context %p"
-nbd_co_send_simple_reply(uint64_t handle, uint32_t error, const char *errname, int len) "Send simple reply: handle = %" PRIu64 ", error = %" PRIu32 " (%s), len = %d"
-nbd_co_send_structured_done(uint64_t handle) "Send structured reply done: handle = %" PRIu64
-nbd_co_send_structured_read(uint64_t handle, uint64_t offset, void *data, size_t size) "Send structured read data reply: handle = %" PRIu64 ", offset = %" PRIu64 ", data = %p, len = %zu"
-nbd_co_send_structured_read_hole(uint64_t handle, uint64_t offset, size_t size) "Send structured read hole reply: handle = %" PRIu64 ", offset = %" PRIu64 ", len = %zu"
-nbd_co_send_extents(uint64_t handle, unsigned int extents, uint32_t id, uint64_t length, int last) "Send block status reply: handle = %" PRIu64 ", extents = %u, context = %d (extents cover %" PRIu64 " bytes, last chunk = %d)"
-nbd_co_send_structured_error(uint64_t handle, int err, const char *errname, const char *msg) "Send structured error reply: handle = %" PRIu64 ", error = %d (%s), msg = '%s'"
-nbd_co_receive_request_decode_type(uint64_t handle, uint16_t type, const char *name) "Decoding type: handle = %" PRIu64 ", type = %" PRIu16 " (%s)"
-nbd_co_receive_request_payload_received(uint64_t handle, uint32_t len) "Payload received: handle = %" PRIu64 ", len = %" PRIu32
+nbd_co_send_simple_reply(uint64_t cookie, uint32_t error, const char *errname, int len) "Send simple reply: cookie = %" PRIu64 ", error = %" PRIu32 " (%s), len = %d"
+nbd_co_send_chunk_done(uint64_t cookie) "Send structured reply done: cookie = %" PRIu64
+nbd_co_send_chunk_read(uint64_t cookie, uint64_t offset, void *data, size_t size) "Send structured read data reply: cookie = %" PRIu64 ", offset = %" PRIu64 ", data = %p, len = %zu"
+nbd_co_send_chunk_read_hole(uint64_t cookie, uint64_t offset, size_t size) "Send structured read hole reply: cookie = %" PRIu64 ", offset = %" PRIu64 ", len = %zu"
+nbd_co_send_extents(uint64_t cookie, unsigned int extents, uint32_t id, uint64_t length, int last) "Send block status reply: cookie = %" PRIu64 ", extents = %u, context = %d (extents cover %" PRIu64 " bytes, last chunk = %d)"
+nbd_co_send_chunk_error(uint64_t cookie, int err, const char *errname, const char *msg) "Send structured error reply: cookie = %" PRIu64 ", error = %d (%s), msg = '%s'"
+nbd_co_receive_request_decode_type(uint64_t cookie, uint16_t type, const char *name) "Decoding type: cookie = %" PRIu64 ", type = %" PRIu16 " (%s)"
+nbd_co_receive_request_payload_received(uint64_t cookie, uint32_t len) "Payload received: cookie = %" PRIu64 ", len = %" PRIu32
 nbd_co_receive_align_compliance(const char *op, uint64_t from, uint32_t len, uint32_t align) "client sent non-compliant unaligned %s request: from=0x%" PRIx64 ", len=0x%" PRIx32 ", align=0x%" PRIx32
 nbd_trip(void) "Reading request"