Re: [Qemu-devel] [PATCH v2 1/2] nbd: BLOCK_STATUS constants

[Vladimir Sementsov-Ogievskiy]

26.02.2018 19:57, Eric Blake wrote:

From: Vladimir Sementsov-Ogievskiy 

Expose the new constants and structs that will be used by both
server and client implementations of NBD_CMD_BLOCK_STATUS (the
command is currently experimental at
https://github.com/NetworkBlockDevice/nbd/blob/extension-blockstatus/doc/proto.md
but will hopefully be stabilized soon).

Signed-off-by: Vladimir Sementsov-Ogievskiy 
Message-Id: <1518702707-7077-4-git-send-email-vsement...@virtuozzo.com>
[eblake: split from larger patch on server implementation]
Signed-off-by: Eric Blake 


ok, with NBD_REPLY_TYPE_BLOCK_STATUS switched back to 5, as it was decided.


--
Best regards,
Vladimir

[Qemu-devel] [PATCH v2 1/2] nbd: BLOCK_STATUS constants

[Eric Blake]

From: Vladimir Sementsov-Ogievskiy 

Expose the new constants and structs that will be used by both
server and client implementations of NBD_CMD_BLOCK_STATUS (the
command is currently experimental at
https://github.com/NetworkBlockDevice/nbd/blob/extension-blockstatus/doc/proto.md
but will hopefully be stabilized soon).

Signed-off-by: Vladimir Sementsov-Ogievskiy 
Message-Id: <1518702707-7077-4-git-send-email-vsement...@virtuozzo.com>
[eblake: split from larger patch on server implementation]
Signed-off-by: Eric Blake 
---
 include/block/nbd.h | 31 +++
 nbd/common.c| 10 ++
 2 files changed, 41 insertions(+)

diff --git a/include/block/nbd.h b/include/block/nbd.h
index ef1698914ba..53250d0979c 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -41,6 +41,12 @@ struct NBDOptionReply {
 } QEMU_PACKED;
 typedef struct NBDOptionReply NBDOptionReply;

+typedef struct NBDOptionReplyMetaContext {
+NBDOptionReply h; /* h.type = NBD_REP_META_CONTEXT, h.length > 4 */
+uint32_t context_id;
+/* meta context name follows */
+} QEMU_PACKED NBDOptionReplyMetaContext;
+
 /* Transmission phase structs
  *
  * Note: these are _NOT_ the same as the network representation of an NBD
@@ -105,6 +111,19 @@ typedef struct NBDStructuredError {
 uint16_t message_length;
 } QEMU_PACKED NBDStructuredError;

+/* Header of NBD_REPLY_TYPE_BLOCK_STATUS */
+typedef struct NBDStructuredMeta {
+NBDStructuredReplyChunk h; /* h.length >= 12 (at least one extent) */
+uint32_t context_id;
+/* extents follows */
+} QEMU_PACKED NBDStructuredMeta;
+
+/* Extent chunk for NBD_REPLY_TYPE_BLOCK_STATUS */
+typedef struct NBDExtent {
+uint32_t length;
+uint32_t flags; /* NBD_STATE_* */
+} QEMU_PACKED NBDExtent;
+
 /* Transmission (export) flags: sent from server to client during handshake,
but describe what will happen during transmission */
 #define NBD_FLAG_HAS_FLAGS (1 << 0) /* Flags are there */
@@ -136,6 +155,8 @@ typedef struct NBDStructuredError {
 #define NBD_OPT_INFO  (6)
 #define NBD_OPT_GO(7)
 #define NBD_OPT_STRUCTURED_REPLY  (8)
+#define NBD_OPT_LIST_META_CONTEXT (9)
+#define NBD_OPT_SET_META_CONTEXT  (10)

 /* Option reply types. */
 #define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value))
@@ -143,6 +164,7 @@ typedef struct NBDStructuredError {
 #define NBD_REP_ACK (1)/* Data sending finished. */
 #define NBD_REP_SERVER  (2)/* Export description. */
 #define NBD_REP_INFO(3)/* NBD_OPT_INFO/GO. */
+#define NBD_REP_META_CONTEXT(4)/* NBD_OPT_{LIST,SET}_META_CONTEXT */

 #define NBD_REP_ERR_UNSUP   NBD_REP_ERR(1)  /* Unknown option */
 #define NBD_REP_ERR_POLICY  NBD_REP_ERR(2)  /* Server denied */
@@ -163,6 +185,8 @@ typedef struct NBDStructuredError {
 #define NBD_CMD_FLAG_FUA(1 << 0) /* 'force unit access' during write */
 #define NBD_CMD_FLAG_NO_HOLE(1 << 1) /* don't punch hole on zero run */
 #define NBD_CMD_FLAG_DF (1 << 2) /* don't fragment structured read */
+#define NBD_CMD_FLAG_REQ_ONE(1 << 3) /* only one extent in BLOCK_STATUS
+  * reply chunk */

 /* Supported request types */
 enum {
@@ -173,6 +197,7 @@ enum {
 NBD_CMD_TRIM = 4,
 /* 5 reserved for failed experiment NBD_CMD_CACHE */
 NBD_CMD_WRITE_ZEROES = 6,
+NBD_CMD_BLOCK_STATUS = 7,
 };

 #define NBD_DEFAULT_PORT   10809
@@ -200,9 +225,15 @@ enum {
 #define NBD_REPLY_TYPE_NONE  0
 #define NBD_REPLY_TYPE_OFFSET_DATA   1
 #define NBD_REPLY_TYPE_OFFSET_HOLE   2
+#define NBD_REPLY_TYPE_BLOCK_STATUS  3
 #define NBD_REPLY_TYPE_ERROR NBD_REPLY_ERR(1)
 #define NBD_REPLY_TYPE_ERROR_OFFSET  NBD_REPLY_ERR(2)

+/* Flags for extents (NBDExtent.flags) of NBD_REPLY_TYPE_BLOCK_STATUS,
+ * for base:allocation meta context */
+#define NBD_STATE_HOLE (1 << 0)
+#define NBD_STATE_ZERO (1 << 1)
+
 static inline bool nbd_reply_type_is_error(int type)
 {
 return type & (1 << 15);
diff --git a/nbd/common.c b/nbd/common.c
index 6295526dd14..8c95c1d606e 100644
--- a/nbd/common.c
+++ b/nbd/common.c
@@ -75,6 +75,10 @@ const char *nbd_opt_lookup(uint32_t opt)
 return "go";
 case NBD_OPT_STRUCTURED_REPLY:
 return "structured reply";
+case NBD_OPT_LIST_META_CONTEXT:
+return "list meta context";
+case NBD_OPT_SET_META_CONTEXT:
+return "set meta context";
 default:
 return "";
 }
@@ -90,6 +94,8 @@ const char *nbd_rep_lookup(uint32_t rep)
 return "server";
 case NBD_REP_INFO:
 return "info";
+case NBD_REP_META_CONTEXT:
+return "meta context";
 case NBD_REP_ERR_UNSUP:
 return "unsupported";
 case NBD_REP_ERR_POLICY:
@@ -144,6 +150,8 @@ const char *nbd_cmd_lookup(uint16_t cmd)
 return "trim";
 case NBD_CMD_WRITE_ZEROES: