5:15 p.m.
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 <eblake(a)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