[PATCH v5 14/17] nbd/client: Request extended headers during negotiation

[Eric Blake <eblake@redhat.com>]

All the pieces are in place for a client to finally request extended
headers.  Note that we must not request extended headers when qemu-nbd
is used to connect to the kernel module (as nbd.ko does not expect
them, but expects us to do the negotiation in userspace before handing
the socket over to the kernel), but there is no harm in all other
clients requesting them.

Extended headers are not essential to the information collected during
'qemu-nbd --list', but probing for it gives us one more piece of
information in that output.  Update the iotests affected by the new
line of output.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---

v5: add R-b

v4: rebase to earlier changes, tweak commit message for why qemu-nbd
connection to /dev/nbd cannot use extended mode [Vladimir]
---
 nbd/client-connection.c                       |  2 +-
 nbd/client.c                                  | 20 ++++++++++++++-----
 qemu-nbd.c                                    |  3 +++
 tests/qemu-iotests/223.out                    |  6 ++++++
 tests/qemu-iotests/233.out                    |  4 ++++
 tests/qemu-iotests/241.out                    |  3 +++
 tests/qemu-iotests/307.out                    |  5 +++++
 .../tests/nbd-qemu-allocation.out             |  1 +
 8 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/nbd/client-connection.c b/nbd/client-connection.c
index 13e4cb6684b..d9d946da006 100644
--- a/nbd/client-connection.c
+++ b/nbd/client-connection.c
@@ -93,7 +93,7 @@ NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr,
         .do_negotiation = do_negotiation,

         .initial_info.request_sizes = true,
-        .initial_info.mode = NBD_MODE_STRUCTURED,
+        .initial_info.mode = NBD_MODE_EXTENDED,
         .initial_info.base_allocation = true,
         .initial_info.x_dirty_bitmap = g_strdup(x_dirty_bitmap),
         .initial_info.name = g_strdup(export_name ?: "")
diff --git a/nbd/client.c b/nbd/client.c
index e78d6c00f18..4520c08049e 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -958,15 +958,23 @@ static int nbd_start_negotiate(AioContext *aio_context, QIOChannel *ioc,
         if (fixedNewStyle) {
             int result = 0;

+            if (max_mode >= NBD_MODE_EXTENDED) {
+                result = nbd_request_simple_option(ioc,
+                                                   NBD_OPT_EXTENDED_HEADERS,
+                                                   false, errp);
+                if (result) {
+                    return result < 0 ? -EINVAL : NBD_MODE_EXTENDED;
+                }
+            }
             if (max_mode >= NBD_MODE_STRUCTURED) {
                 result = nbd_request_simple_option(ioc,
                                                    NBD_OPT_STRUCTURED_REPLY,
                                                    false, errp);
-                if (result < 0) {
-                    return -EINVAL;
+                if (result) {
+                    return result < 0 ? -EINVAL : NBD_MODE_STRUCTURED;
                 }
             }
-            return result ? NBD_MODE_STRUCTURED : NBD_MODE_SIMPLE;
+            return NBD_MODE_SIMPLE;
         } else {
             return NBD_MODE_EXPORT_NAME;
         }
@@ -1040,6 +1048,7 @@ int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
     }

     switch (info->mode) {
+    case NBD_MODE_EXTENDED:
     case NBD_MODE_STRUCTURED:
         if (base_allocation) {
             result = nbd_negotiate_simple_meta_context(ioc, info, errp);
@@ -1150,7 +1159,7 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,

     *info = NULL;
     result = nbd_start_negotiate(NULL, ioc, tlscreds, hostname, &sioc,
-                                 NBD_MODE_STRUCTURED, NULL, errp);
+                                 NBD_MODE_EXTENDED, NULL, errp);
     if (tlscreds && sioc) {
         ioc = sioc;
     }
@@ -1161,6 +1170,7 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
     switch ((NBDMode)result) {
     case NBD_MODE_SIMPLE:
     case NBD_MODE_STRUCTURED:
+    case NBD_MODE_EXTENDED:
         /* 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. */
@@ -1197,7 +1207,7 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
                 break;
             }

-            if (result == NBD_MODE_STRUCTURED &&
+            if (result >= NBD_MODE_STRUCTURED &&
                 nbd_list_meta_contexts(ioc, &array[i], errp) < 0) {
                 goto out;
             }
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 32c5a349e06..ca846f7d96d 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -237,6 +237,9 @@ static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
             printf("  opt block: %u\n", list[i].opt_block);
             printf("  max block: %u\n", list[i].max_block);
         }
+        printf("  transaction size: %s\n",
+               list[i].mode >= NBD_MODE_EXTENDED ?
+               "64-bit" : "32-bit");
         if (list[i].n_contexts) {
             printf("  available meta contexts: %d\n", list[i].n_contexts);
             for (j = 0; j < list[i].n_contexts; j++) {
diff --git a/tests/qemu-iotests/223.out b/tests/qemu-iotests/223.out
index 26fb347c5da..b98582c38ea 100644
--- a/tests/qemu-iotests/223.out
+++ b/tests/qemu-iotests/223.out
@@ -87,6 +87,7 @@ exports available: 3
   min block: 1
   opt block: 4096
   max block: 33554432
+  transaction size: 64-bit
   available meta contexts: 2
    base:allocation
    qemu:dirty-bitmap:b
@@ -97,6 +98,7 @@ exports available: 3
   min block: 1
   opt block: 4096
   max block: 33554432
+  transaction size: 64-bit
   available meta contexts: 2
    base:allocation
    qemu:dirty-bitmap:b2
@@ -106,6 +108,7 @@ exports available: 3
   min block: 1
   opt block: 4096
   max block: 33554432
+  transaction size: 64-bit
   available meta contexts: 2
    base:allocation
    qemu:dirty-bitmap:b3
@@ -206,6 +209,7 @@ exports available: 3
   min block: 1
   opt block: 4096
   max block: 33554432
+  transaction size: 64-bit
   available meta contexts: 2
    base:allocation
    qemu:dirty-bitmap:b
@@ -216,6 +220,7 @@ exports available: 3
   min block: 1
   opt block: 4096
   max block: 33554432
+  transaction size: 64-bit
   available meta contexts: 2
    base:allocation
    qemu:dirty-bitmap:b2
@@ -225,6 +230,7 @@ exports available: 3
   min block: 1
   opt block: 4096
   max block: 33554432
+  transaction size: 64-bit
   available meta contexts: 2
    base:allocation
    qemu:dirty-bitmap:b3
diff --git a/tests/qemu-iotests/233.out b/tests/qemu-iotests/233.out
index 237c82767ea..1910f7df20f 100644
--- a/tests/qemu-iotests/233.out
+++ b/tests/qemu-iotests/233.out
@@ -39,6 +39,7 @@ exports available: 1
  export: ''
   size:  67108864
   min block: 1
+  transaction size: 64-bit

 == check TLS fail over TCP with mismatched hostname ==
 qemu-img: Could not open 'driver=nbd,host=localhost,port=PORT,tls-creds=tls0': Certificate does not match the hostname localhost
@@ -53,6 +54,7 @@ exports available: 1
  export: ''
   size:  67108864
   min block: 1
+  transaction size: 64-bit

 == check TLS with different CA fails ==
 qemu-img: Could not open 'driver=nbd,host=127.0.0.1,port=PORT,tls-creds=tls0': The certificate hasn't got a known issuer
@@ -83,6 +85,7 @@ exports available: 1
  export: ''
   size:  67108864
   min block: 1
+  transaction size: 64-bit

 == check TLS works over UNIX with PSK ==
 image: nbd+unix://?socket=SOCK_DIR/qemu-nbd.sock
@@ -93,6 +96,7 @@ exports available: 1
  export: ''
   size:  67108864
   min block: 1
+  transaction size: 64-bit

 == check TLS fails over UNIX with mismatch PSK ==
 qemu-img: Could not open 'driver=nbd,path=SOCK_DIR/qemu-nbd.sock,tls-creds=tls0': TLS handshake failed: The TLS connection was non-properly terminated.
diff --git a/tests/qemu-iotests/241.out b/tests/qemu-iotests/241.out
index 88e8cfcd7e2..a9efb876521 100644
--- a/tests/qemu-iotests/241.out
+++ b/tests/qemu-iotests/241.out
@@ -6,6 +6,7 @@ exports available: 1
  export: ''
   size:  1024
   min block: 1
+  transaction size: 64-bit
 [{ "start": 0, "length": 1000, "depth": 0, "present": true, "zero": false, "data": true, "offset": OFFSET},
 { "start": 1000, "length": 24, "depth": 0, "present": true, "zero": true, "data": false, "offset": OFFSET}]
 1 KiB (0x400) bytes     allocated at offset 0 bytes (0x0)
@@ -16,6 +17,7 @@ exports available: 1
  export: ''
   size:  1024
   min block: 512
+  transaction size: 64-bit
 [{ "start": 0, "length": 1024, "depth": 0, "present": true, "zero": false, "data": true, "offset": OFFSET}]
 1 KiB (0x400) bytes     allocated at offset 0 bytes (0x0)
 WARNING: Image format was not specified for 'TEST_DIR/t.raw' and probing guessed raw.
@@ -28,6 +30,7 @@ exports available: 1
  export: ''
   size:  1024
   min block: 1
+  transaction size: 64-bit
 [{ "start": 0, "length": 1000, "depth": 0, "present": true, "zero": false, "data": true, "offset": OFFSET},
 { "start": 1000, "length": 24, "depth": 0, "present": true, "zero": true, "data": false, "offset": OFFSET}]
 1 KiB (0x400) bytes     allocated at offset 0 bytes (0x0)
diff --git a/tests/qemu-iotests/307.out b/tests/qemu-iotests/307.out
index 390f05d1b78..2b9a6a67a1a 100644
--- a/tests/qemu-iotests/307.out
+++ b/tests/qemu-iotests/307.out
@@ -19,6 +19,7 @@ exports available: 1
   min block: XXX
   opt block: XXX
   max block: XXX
+  transaction size: 64-bit
   available meta contexts: 1
    base:allocation

@@ -47,6 +48,7 @@ exports available: 1
   min block: XXX
   opt block: XXX
   max block: XXX
+  transaction size: 64-bit
   available meta contexts: 1
    base:allocation

@@ -78,6 +80,7 @@ exports available: 2
   min block: XXX
   opt block: XXX
   max block: XXX
+  transaction size: 64-bit
   available meta contexts: 1
    base:allocation
  export: 'export1'
@@ -87,6 +90,7 @@ exports available: 2
   min block: XXX
   opt block: XXX
   max block: XXX
+  transaction size: 64-bit
   available meta contexts: 1
    base:allocation

@@ -113,6 +117,7 @@ exports available: 1
   min block: XXX
   opt block: XXX
   max block: XXX
+  transaction size: 64-bit
   available meta contexts: 1
    base:allocation

diff --git a/tests/qemu-iotests/tests/nbd-qemu-allocation.out b/tests/qemu-iotests/tests/nbd-qemu-allocation.out
index 9d938db24e6..659276032b0 100644
--- a/tests/qemu-iotests/tests/nbd-qemu-allocation.out
+++ b/tests/qemu-iotests/tests/nbd-qemu-allocation.out
@@ -21,6 +21,7 @@ exports available: 1
   min block: 1
   opt block: 4096
   max block: 33554432
+  transaction size: 64-bit
   available meta contexts: 2
    base:allocation
    qemu:allocation-depth
-- 
2.41.0