nbd patches for 2017-11-09

- Vladimir Sementsov-Ogievskiy: nbd/server: fix nbd_negotiate_handle_info
 - Eric Blake: 0/7 various NBD fixes for 2.11
 -----BEGIN PGP SIGNATURE-----
 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg
 
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 =K/Rz
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Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2017-11-09' into staging

nbd patches for 2017-11-09

- Vladimir Sementsov-Ogievskiy: nbd/server: fix nbd_negotiate_handle_info
- Eric Blake: 0/7 various NBD fixes for 2.11

# gpg: Signature made Thu 09 Nov 2017 16:56:58 GMT
# gpg:                using RSA key 0xA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2017-11-09:
  nbd/server: Fix structured read of length 0
  nbd-client: Stricter enforcing of structured reply spec
  nbd-client: Short-circuit 0-length operations
  nbd: Fix struct name for structured reads
  nbd/client: Nicer trace of structured reply
  nbd-client: Refuse read-only client with BDRV_O_RDWR
  nbd-client: Fix error message typos
  nbd/server: fix nbd_negotiate_handle_info

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

block/nbd-client.c

@@ -216,7 +216,7 @@ static int nbd_parse_offset_hole_payload(NBDStructuredReplyChunk *chunk,
     offset = payload_advance64(&payload);
     hole_size = payload_advance32(&payload);
 
-    if (offset < orig_offset || hole_size > qiov->size ||
+    if (!hole_size || offset < orig_offset || hole_size > qiov->size ||
         offset > orig_offset + qiov->size - hole_size) {
         error_setg(errp, "Protocol error: server sent chunk exceeding requested"
                          " region");
@@ -248,7 +248,7 @@ static int nbd_parse_error_payload(NBDStructuredReplyChunk *chunk,
 
     error = nbd_errno_to_system_errno(payload_advance32(&payload));
     if (error == 0) {
-        error_setg(errp, "Protocol error: server sent structured error chunk"
+        error_setg(errp, "Protocol error: server sent structured error chunk "
                          "with error = 0");
         return -EINVAL;
     }
@@ -257,7 +257,7 @@ static int nbd_parse_error_payload(NBDStructuredReplyChunk *chunk,
     message_size = payload_advance16(&payload);
 
     if (message_size > chunk->length - sizeof(error) - sizeof(message_size)) {
-        error_setg(errp, "Protocol error: server sent structured error chunk"
+        error_setg(errp, "Protocol error: server sent structured error chunk "
                          "with incorrect message size");
         return -EINVAL;
     }
@@ -281,7 +281,8 @@ static int nbd_co_receive_offset_data_payload(NBDClientSession *s,
 
     assert(nbd_reply_is_structured(&s->reply));
 
-    if (chunk->length < sizeof(offset)) {
+    /* The NBD spec requires at least one byte of payload */
+    if (chunk->length <= sizeof(offset)) {
         error_setg(errp, "Protocol error: invalid payload for "
                          "NBD_REPLY_TYPE_OFFSET_DATA");
         return -EINVAL;
@@ -293,6 +294,7 @@ static int nbd_co_receive_offset_data_payload(NBDClientSession *s,
     be64_to_cpus(&offset);
 
     data_size = chunk->length - sizeof(offset);
+    assert(data_size);
     if (offset < orig_offset || data_size > qiov->size ||
         offset > orig_offset + qiov->size - data_size) {
         error_setg(errp, "Protocol error: server sent chunk exceeding requested"
@@ -408,7 +410,12 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
     if (chunk->type == NBD_REPLY_TYPE_NONE) {
         if (!(chunk->flags & NBD_REPLY_FLAG_DONE)) {
             error_setg(errp, "Protocol error: NBD_REPLY_TYPE_NONE chunk without"
-                             "NBD_REPLY_FLAG_DONE flag set");
+                       " NBD_REPLY_FLAG_DONE flag set");
+            return -EINVAL;
+        }
+        if (chunk->length) {
+            error_setg(errp, "Protocol error: NBD_REPLY_TYPE_NONE chunk with"
+                       " nonzero length");
             return -EINVAL;
         }
         return 0;
@@ -674,6 +681,9 @@ int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
     assert(bytes <= NBD_MAX_BUFFER_SIZE);
     assert(!flags);
 
+    if (!bytes) {
+        return 0;
+    }
     ret = nbd_co_send_request(bs, &request, NULL);
     if (ret < 0) {
         return ret;
@@ -697,6 +707,7 @@ int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset,
         .len = bytes,
     };
 
+    assert(!(client->info.flags & NBD_FLAG_READ_ONLY));
     if (flags & BDRV_REQ_FUA) {
         assert(client->info.flags & NBD_FLAG_SEND_FUA);
         request.flags |= NBD_CMD_FLAG_FUA;
@@ -704,6 +715,9 @@ int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset,
 
     assert(bytes <= NBD_MAX_BUFFER_SIZE);
 
+    if (!bytes) {
+        return 0;
+    }
     return nbd_co_request(bs, &request, qiov);
 }
 
@@ -717,6 +731,7 @@ int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
         .len = bytes,
     };
 
+    assert(!(client->info.flags & NBD_FLAG_READ_ONLY));
     if (!(client->info.flags & NBD_FLAG_SEND_WRITE_ZEROES)) {
         return -ENOTSUP;
     }
@@ -729,6 +744,9 @@ int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
         request.flags |= NBD_CMD_FLAG_NO_HOLE;
     }
 
+    if (!bytes) {
+        return 0;
+    }
     return nbd_co_request(bs, &request, NULL);
 }
 
@@ -756,7 +774,8 @@ int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes)
         .len = bytes,
     };
 
-    if (!(client->info.flags & NBD_FLAG_SEND_TRIM)) {
+    assert(!(client->info.flags & NBD_FLAG_READ_ONLY));
+    if (!(client->info.flags & NBD_FLAG_SEND_TRIM) || !bytes) {
         return 0;
     }
 
@@ -814,6 +833,12 @@ int nbd_client_init(BlockDriverState *bs,
         logout("Failed to negotiate with the NBD server\n");
         return ret;
     }
+    if (client->info.flags & NBD_FLAG_READ_ONLY &&
+        !bdrv_is_read_only(bs)) {
+        error_setg(errp,
+                   "request for write access conflicts with read-only export");
+        return -EACCES;
+    }
     if (client->info.flags & NBD_FLAG_SEND_FUA) {
         bs->supported_write_flags = BDRV_REQ_FUA;
         bs->supported_zero_flags |= BDRV_REQ_FUA;

include/block/nbd.h

@@ -86,15 +86,23 @@ typedef union NBDReply {
     } QEMU_PACKED;
 } NBDReply;
 
-/* Header of NBD_REPLY_TYPE_OFFSET_DATA, complete NBD_REPLY_TYPE_OFFSET_HOLE */
+/* Header of chunk for NBD_REPLY_TYPE_OFFSET_DATA */
-typedef struct NBDStructuredRead {
+typedef struct NBDStructuredReadData {
-    NBDStructuredReplyChunk h;
+    NBDStructuredReplyChunk h; /* h.length >= 9 */
     uint64_t offset;
-} QEMU_PACKED NBDStructuredRead;
+    /* At least one byte of data payload follows, calculated from h.length */
+} QEMU_PACKED NBDStructuredReadData;
+
+/* Complete chunk for NBD_REPLY_TYPE_OFFSET_HOLE */
+typedef struct NBDStructuredReadHole {
+    NBDStructuredReplyChunk h; /* h.length == 12 */
+    uint64_t offset;
+    uint32_t length;
+} QEMU_PACKED NBDStructuredReadHole;
 
 /* Header of all NBD_REPLY_TYPE_ERROR* errors */
 typedef struct NBDStructuredError {
-    NBDStructuredReplyChunk h;
+    NBDStructuredReplyChunk h; /* h.length >= 6 */
     uint32_t error;
     uint16_t message_length;
 } QEMU_PACKED NBDStructuredError;

nbd/client.c

@@ -979,6 +979,7 @@ static int nbd_receive_structured_reply_chunk(QIOChannel *ioc,
 int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp)
 {
     int ret;
+    const char *type;
 
     ret = nbd_read_eof(ioc, &reply->magic, sizeof(reply->magic), errp);
     if (ret <= 0) {
@@ -1008,8 +1009,9 @@ int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp)
         if (ret < 0) {
             break;
         }
+        type = nbd_reply_type_lookup(reply->structured.type);
         trace_nbd_receive_structured_reply_chunk(reply->structured.flags,
-                                                 reply->structured.type,
+                                                 reply->structured.type, type,
                                                  reply->structured.handle,
                                                  reply->structured.length);
         break;

nbd/server.c

@@ -423,6 +423,7 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length,
             break;
         }
     }
+    assert(length == 0);
 
     exp = nbd_export_find(name);
     if (!exp) {
@@ -433,7 +434,7 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length,
 
     /* Don't bother sending NBD_INFO_NAME unless client requested it */
     if (sendname) {
-        rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, length, name,
+        rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, namelen, name,
                                      errp);
         if (rc < 0) {
             return rc;
@@ -1272,6 +1273,21 @@ static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags,
     stl_be_p(&chunk->length, length);
 }
 
+static int coroutine_fn nbd_co_send_structured_done(NBDClient *client,
+                                                    uint64_t handle,
+                                                    Error **errp)
+{
+    NBDStructuredReplyChunk chunk;
+    struct iovec iov[] = {
+        {.iov_base = &chunk, .iov_len = sizeof(chunk)},
+    };
+
+    trace_nbd_co_send_structured_done(handle);
+    set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0);
+
+    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,
@@ -1279,12 +1295,13 @@ static int coroutine_fn nbd_co_send_structured_read(NBDClient *client,
                                                     size_t size,
                                                     Error **errp)
 {
-    NBDStructuredRead chunk;
+    NBDStructuredReadData chunk;
     struct iovec iov[] = {
         {.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, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_OFFSET_DATA,
                  handle, sizeof(chunk) - sizeof(chunk.h) + size);
@@ -1543,10 +1560,13 @@ reply:
         if (ret < 0) {
             ret = nbd_co_send_structured_error(req->client, request.handle,
                                                -ret, msg, &local_err);
-        } else {
+        } else if (reply_data_len) {
             ret = nbd_co_send_structured_read(req->client, request.handle,
                                               request.from, req->data,
                                               reply_data_len, &local_err);
+        } else {
+            ret = nbd_co_send_structured_done(req->client, request.handle,
+                                              &local_err);
         }
     } else {
         ret = nbd_co_send_simple_reply(req->client, request.handle,

nbd/trace-events

@@ -27,7 +27,7 @@ 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, uint64_t handle, uint32_t length) "Got structured reply chunk: { flags = 0x%" PRIx16 ", type = %d, handle = %" PRIu64 ", length = %" PRIu32 " }"
+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/common.c
 nbd_unknown_error(int err) "Squashing unexpected error %d to EINVAL"
@@ -55,6 +55,7 @@ nbd_receive_request(uint32_t magic, uint16_t flags, uint16_t type, uint64_t from
 nbd_blk_aio_attached(const char *name, void *ctx) "Export %s: Attaching clients to AIO context %p\n"
 nbd_blk_aio_detach(const char *name, void *ctx) "Export %s: Detaching clients from AIO context %p\n"
 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_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)"

tests/qemu-iotests/058

@@ -117,15 +117,15 @@ _export_nbd_snapshot sn1
 
 echo
 echo "== verifying the exported snapshot with patterns, method 1 =="
-$QEMU_IO_NBD -c 'read -P 0xa 0x1000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
+$QEMU_IO_NBD -r -c 'read -P 0xa 0x1000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
-$QEMU_IO_NBD -c 'read -P 0xb 0x2000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
+$QEMU_IO_NBD -r -c 'read -P 0xb 0x2000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
 
 _export_nbd_snapshot1 sn1
 
 echo
 echo "== verifying the exported snapshot with patterns, method 2 =="
-$QEMU_IO_NBD -c 'read -P 0xa 0x1000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
+$QEMU_IO_NBD -r -c 'read -P 0xa 0x1000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
-$QEMU_IO_NBD -c 'read -P 0xb 0x2000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
+$QEMU_IO_NBD -r -c 'read -P 0xb 0x2000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
 
 $QEMU_IMG convert "$TEST_IMG" -l sn1 -O qcow2 "$converted_image"
 

tests/qemu-iotests/140

@@ -78,7 +78,7 @@ _send_qemu_cmd $QEMU_HANDLE \
        'arguments': { 'device': 'drv' }}" \
     'return'
 
-$QEMU_IO_PROG -f raw -c 'read -P 42 0 64k' \
+$QEMU_IO_PROG -f raw -r -c 'read -P 42 0 64k' \
     "nbd+unix:///drv?socket=$TEST_DIR/nbd" 2>&1 \
     | _filter_qemu_io | _filter_nbd
 
@@ -87,7 +87,7 @@ _send_qemu_cmd $QEMU_HANDLE \
        'arguments': { 'device': 'drv' }}" \
     'return'
 
-$QEMU_IO_PROG -f raw -c close \
+$QEMU_IO_PROG -f raw -r -c close \
     "nbd+unix:///drv?socket=$TEST_DIR/nbd" 2>&1 \
     | _filter_qemu_io | _filter_nbd
 

tests/qemu-iotests/147

@@ -43,6 +43,7 @@ class NBDBlockdevAddBase(iotests.QMPTestCase):
                     'driver': 'raw',
                     'file': {
                         'driver': 'nbd',
+                        'read-only': True,
                         'server': address
                     } }
         if export is not None: