We have no reason to send NBD_REPLY_TYPE_OFFSET_HOLE_EXT since we already cap NBD_CMD_READ to 32M. For NBD_CMD_WRITE_ZEROES and NBD_CMD_TRIM, the block layer already supports 64-bit operations without any effort on our part. For NBD_CMD_BLOCK_STATUS, the client's length is a hint; the easiest approach is to truncate our answer back to 32 bits, letting us delay the effort of implementing NBD_REPLY_TYPE_BLOCK_STATUS_EXT to a separate patch.
Signed-off-by: Eric Blake <ebl...@redhat.com> --- nbd/nbd-internal.h | 5 ++- nbd/server.c | 106 ++++++++++++++++++++++++++++++++++----------- 2 files changed, 85 insertions(+), 26 deletions(-) diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h index 0016793ff4b1..875b6204c28c 100644 --- a/nbd/nbd-internal.h +++ b/nbd/nbd-internal.h @@ -35,8 +35,11 @@ * https://github.com/yoe/nbd/blob/master/doc/proto.md */ -/* Size of all NBD_OPT_*, without payload */ +/* Size of all compact NBD_CMD_*, without payload */ #define NBD_REQUEST_SIZE (4 + 2 + 2 + 8 + 8 + 4) +/* Size of all extended NBD_CMD_*, without payload */ +#define NBD_REQUEST_EXT_SIZE (4 + 2 + 2 + 8 + 8 + 8) + /* Size of all NBD_REP_* sent in answer to most NBD_OPT_*, without payload */ #define NBD_REPLY_SIZE (4 + 4 + 8) /* Size of reply to NBD_OPT_EXPORT_NAME */ diff --git a/nbd/server.c b/nbd/server.c index 4306fa7b426c..0e496f60ffbd 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -142,6 +142,7 @@ struct NBDClient { uint32_t check_align; /* If non-zero, check for aligned client requests */ bool structured_reply; + bool extended_headers; NBDExportMetaContexts export_meta; uint32_t opt; /* Current option being negotiated */ @@ -1275,6 +1276,19 @@ static int nbd_negotiate_options(NBDClient *client, Error **errp) errp); break; + case NBD_OPT_EXTENDED_HEADERS: + if (length) { + ret = nbd_reject_length(client, false, errp); + } else if (client->extended_headers) { + ret = nbd_negotiate_send_rep_err( + client, NBD_REP_ERR_INVALID, errp, + "extended headers already negotiated"); + } else { + ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); + client->extended_headers = true; + } + break; + default: ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, "Unsupported option %" PRIu32 " (%s)", @@ -1410,11 +1424,13 @@ nbd_read_eof(NBDClient *client, void *buffer, size_t size, Error **errp) static int nbd_receive_request(NBDClient *client, NBDRequest *request, Error **errp) { - uint8_t buf[NBD_REQUEST_SIZE]; - uint32_t magic; + uint8_t buf[NBD_REQUEST_EXT_SIZE]; + uint32_t magic, expect; int ret; + size_t size = client->extended_headers ? NBD_REQUEST_EXT_SIZE + : NBD_REQUEST_SIZE; - ret = nbd_read_eof(client, buf, sizeof(buf), errp); + ret = nbd_read_eof(client, buf, size, errp); if (ret < 0) { return ret; } @@ -1422,13 +1438,21 @@ static int nbd_receive_request(NBDClient *client, NBDRequest *request, return -EIO; } - /* Request - [ 0 .. 3] magic (NBD_REQUEST_MAGIC) - [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) - [ 6 .. 7] type (NBD_CMD_READ, ...) - [ 8 .. 15] handle - [16 .. 23] from - [24 .. 27] len + /* + * Compact request + * [ 0 .. 3] magic (NBD_REQUEST_MAGIC) + * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) + * [ 6 .. 7] type (NBD_CMD_READ, ...) + * [ 8 .. 15] handle + * [16 .. 23] from + * [24 .. 27] len + * Extended request + * [ 0 .. 3] magic (NBD_REQUEST_EXT_MAGIC) + * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) + * [ 6 .. 7] type (NBD_CMD_READ, ...) + * [ 8 .. 15] handle + * [16 .. 23] from + * [24 .. 31] len */ magic = ldl_be_p(buf); @@ -1436,12 +1460,18 @@ static int nbd_receive_request(NBDClient *client, NBDRequest *request, request->type = lduw_be_p(buf + 6); request->handle = ldq_be_p(buf + 8); request->from = ldq_be_p(buf + 16); - request->len = ldl_be_p(buf + 24); /* widen 32 to 64 bits */ + if (client->extended_headers) { + request->len = ldq_be_p(buf + 24); + expect = NBD_REQUEST_EXT_MAGIC; + } else { + request->len = ldl_be_p(buf + 24); /* widen 32 to 64 bits */ + expect = NBD_REQUEST_MAGIC; + } trace_nbd_receive_request(magic, request->flags, request->type, request->from, request->len); - if (magic != NBD_REQUEST_MAGIC) { + if (magic != expect) { error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); return -EINVAL; } @@ -1872,12 +1902,22 @@ static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, static inline void set_be_simple_reply(NBDClient *client, struct iovec *iov, uint64_t error, uint64_t handle) { - NBDSimpleReply *reply = iov->iov_base; + if (client->extended_headers) { + NBDSimpleReplyExt *reply = iov->iov_base; - iov->iov_len = sizeof(*reply); - stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); - stl_be_p(&reply->error, error); - stq_be_p(&reply->handle, handle); + iov->iov_len = sizeof(*reply); + stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_EXT_MAGIC); + stl_be_p(&reply->error, error); + stq_be_p(&reply->handle, handle); + reply->_pad1 = reply->_pad2 = 0; + } else { + NBDSimpleReply *reply = iov->iov_base; + + iov->iov_len = sizeof(*reply); + stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); + stl_be_p(&reply->error, error); + stq_be_p(&reply->handle, handle); + } } static int nbd_co_send_simple_reply(NBDClient *client, @@ -1905,14 +1945,26 @@ static inline void set_be_chunk(NBDClient *client, struct iovec *iov, uint16_t flags, uint16_t type, uint64_t handle, uint32_t length) { - NBDStructuredReplyChunk *chunk = iov->iov_base; + if (client->extended_headers) { + NBDStructuredReplyChunkExt *chunk = iov->iov_base; - iov->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); - stl_be_p(&chunk->length, length); + iov->iov_len = sizeof(*chunk); + stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_EXT_MAGIC); + stw_be_p(&chunk->flags, flags); + stw_be_p(&chunk->type, type); + stq_be_p(&chunk->handle, handle); + stq_be_p(&chunk->length, length); + chunk->_pad = 0; + } else { + NBDStructuredReplyChunk *chunk = iov->iov_base; + + iov->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); + stl_be_p(&chunk->length, length); + } } static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, @@ -2555,7 +2607,11 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, return nbd_send_generic_reply(client, request->handle, -EINVAL, "need non-zero length", errp); } - assert(request->len <= UINT32_MAX); + if (request->len > UINT32_MAX) { + /* For now, truncate our response to a 32 bit window */ + request->len = QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES, + client->check_align ?: 1); + } if (client->export_meta.count) { bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; int contexts_remaining = client->export_meta.count; -- 2.33.1