From 4b3d650918d54c4034e0162421410c1a076a057b Mon Sep 17 00:00:00 2001

From: John Snow <jsnow@redhat.com>

Date: Wed, 27 Mar 2019 17:22:49 +0100

Subject: [PATCH 111/163] nbd/client: Pull out oldstyle size determination

RH-Author: John Snow <jsnow@redhat.com>

Message-id: <20190327172308.31077-37-jsnow@redhat.com>

Patchwork-id: 85197

O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 36/55] nbd/client: Pull out oldstyle size determination

Bugzilla: 1691009

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Max Reitz <mreitz@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

From: Eric Blake <eblake@redhat.com>

Another refactoring creating nbd_negotiate_finish_oldstyle()

for further reuse during 'qemu-nbd --list'.

Signed-off-by: Eric Blake <eblake@redhat.com>

Reviewed-by: Richard W.M. Jones <rjones@redhat.com>

Message-Id: <20190117193658.16413-16-eblake@redhat.com>

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

(cherry picked from commit b3c9d33bc4e7c2ab2828b16ebc96f0414b0f1acf)

Signed-off-by: John Snow <jsnow@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 nbd/client.c | 49 ++++++++++++++++++++++++++++++++-----------------

 1 file changed, 32 insertions(+), 17 deletions(-)

diff --git a/nbd/client.c b/nbd/client.c

index 77cc123..6829c68 100644

--- a/nbd/client.c

+++ b/nbd/client.c

@@ -814,7 +814,7 @@ static int nbd_negotiate_simple_meta_context(QIOChannel *ioc,

  * Start the handshake to the server.  After a positive return, the server

  * is ready to accept additional NBD_OPT requests.

  * Returns: negative errno: failure talking to server

- *          0: server is oldstyle, client must still parse export size

+ *          0: server is oldstyle, must call nbd_negotiate_finish_oldstyle

  *          1: server is newstyle, but can only accept EXPORT_NAME

  *          2: server is newstyle, but lacks structured replies

  *          3: server is newstyle and set up for structured replies

@@ -921,6 +921,36 @@ static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,

 }

 /*

+ * nbd_negotiate_finish_oldstyle:

+ * Populate @info with the size and export flags from an oldstyle server,

+ * but does not consume 124 bytes of reserved zero padding.

+ * Returns 0 on success, -1 with @errp set on failure

+ */

+static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info,

+                                         Error **errp)

+{

+    uint32_t oldflags;

+

+    if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {

+        error_prepend(errp, "Failed to read export length: ");

+        return -EINVAL;

+    }

+    info->size = be64_to_cpu(info->size);

+

+    if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {

+        error_prepend(errp, "Failed to read export flags: ");

+        return -EINVAL;

+    }

+    oldflags = be32_to_cpu(oldflags);

+    if (oldflags & ~0xffff) {

+        error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);

+        return -EINVAL;

+    }

+    info->flags = oldflags;

+    return 0;

+}

+

+/*

  * nbd_receive_negotiate:

  * Connect to server, complete negotiation, and move into transmission phase.

  * Returns: negative errno: failure talking to server

@@ -933,7 +963,6 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,

     int result;

     bool zeroes;

     bool base_allocation = info->base_allocation;

-    uint32_t oldflags;

     assert(info->name);

     trace_nbd_receive_negotiate_name(info->name);

@@ -1006,23 +1035,9 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,

             error_setg(errp, "Server does not support non-empty export names");

             return -EINVAL;

         }

-

-        if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {

-            error_prepend(errp, "Failed to read export length: ");

-            return -EINVAL;

-        }

-        info->size = be64_to_cpu(info->size);

-

-        if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {

-            error_prepend(errp, "Failed to read export flags: ");

-            return -EINVAL;

-        }

-        oldflags = be32_to_cpu(oldflags);

-        if (oldflags & ~0xffff) {

-            error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);

+        if (nbd_negotiate_finish_oldstyle(ioc, info, errp) < 0) {

             return -EINVAL;

         }

-        info->flags = oldflags;

         break;

     default:

         return result;

-- 

1.8.3.1