nbd: Merge nbd_export_new() and nbd_export_create()

There is no real reason any more why nbd_export_new() and
nbd_export_create() should be separate functions. The latter only
performs a few checks before it calls the former.

What makes the current state stand out is that it's the only function in
BlockExportDriver that is not a static function inside nbd/server.c, but
a small wrapper in blockdev-nbd.c that then calls back into nbd/server.c
for the real functionality.

Move all the checks to nbd/server.c and make the resulting function
static to improve readability.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-27-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

3 files changed, 45 insertions, 56 deletions

diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 30e165c..8174023 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -37,6 +37,11 @@ void nbd_server_is_qemu_nbd(bool value)
     is_qemu_nbd = value;
 }
 
+bool nbd_server_is_running(void)
+{
+    return nbd_server || is_qemu_nbd;
+}
+
 static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
 {
     nbd_client_put(client);
@@ -173,41 +178,6 @@ void qmp_nbd_server_start(SocketAddressLegacy *addr,
     qapi_free_SocketAddress(addr_flat);
 }
 
-int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args,
-                      Error **errp)
-{
-    BlockExportOptionsNbd *arg = &exp_args->u.nbd;
-
-    assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
-
-    if (!nbd_server && !is_qemu_nbd) {
-        error_setg(errp, "NBD server not running");
-        return -EINVAL;
-    }
-
-    if (!arg->has_name) {
-        arg->name = exp_args->node_name;
-    }
-
-    if (strlen(arg->name) > NBD_MAX_STRING_SIZE) {
-        error_setg(errp, "export name '%s' too long", arg->name);
-        return -EINVAL;
-    }
-
-    if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) {
-        error_setg(errp, "description '%s' too long", arg->description);
-        return -EINVAL;
-    }
-
-    if (nbd_export_find(arg->name)) {
-        error_setg(errp, "NBD server already has export named '%s'", arg->name);
-        return -EEXIST;
-    }
-
-    return nbd_export_new(exp, arg->name, arg->description, arg->bitmap,
-                          !exp_args->writable, !exp_args->writable, errp);
-}
-
 void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp)
 {
     BlockExport *export;
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 5270b7e..3dd9a04 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -330,12 +330,6 @@ int nbd_errno_to_system_errno(int err);
 typedef struct NBDExport NBDExport;
 typedef struct NBDClient NBDClient;
 
-int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args,
-                      Error **errp);
-int nbd_export_new(BlockExport *blk_exp,
-                   const char *name, const char *desc,
-                   const char *bitmap, bool readonly, bool shared,
-                   Error **errp);
 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk);
 
 AioContext *nbd_export_aio_context(NBDExport *exp);
@@ -349,6 +343,7 @@ void nbd_client_get(NBDClient *client);
 void nbd_client_put(NBDClient *client);
 
 void nbd_server_is_qemu_nbd(bool value);
+bool nbd_server_is_running(void);
 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
                       const char *tls_authz, uint32_t max_connections,
                       Error **errp);
diff --git a/nbd/server.c b/nbd/server.c
index 465ec9e..f74766a 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1507,17 +1507,44 @@ void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk)
     blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier);
 }
 
-int nbd_export_new(BlockExport *blk_exp,
-                   const char *name, const char *desc,
-                   const char *bitmap, bool readonly, bool shared,
-                   Error **errp)
+static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args,
+                             Error **errp)
 {
     NBDExport *exp = container_of(blk_exp, NBDExport, common);
+    BlockExportOptionsNbd *arg = &exp_args->u.nbd;
     BlockBackend *blk = blk_exp->blk;
     int64_t size;
     uint64_t perm, shared_perm;
+    bool readonly = !exp_args->writable;
+    bool shared = !exp_args->writable;
     int ret;
 
+    assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
+
+    if (!nbd_server_is_running()) {
+        error_setg(errp, "NBD server not running");
+        return -EINVAL;
+    }
+
+    if (!arg->has_name) {
+        arg->name = exp_args->node_name;
+    }
+
+    if (strlen(arg->name) > NBD_MAX_STRING_SIZE) {
+        error_setg(errp, "export name '%s' too long", arg->name);
+        return -EINVAL;
+    }
+
+    if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) {
+        error_setg(errp, "description '%s' too long", arg->description);
+        return -EINVAL;
+    }
+
+    if (nbd_export_find(arg->name)) {
+        error_setg(errp, "NBD server already has export named '%s'", arg->name);
+        return -EEXIST;
+    }
+
     size = blk_getlength(blk);
     if (size < 0) {
         error_setg_errno(errp, -size,
@@ -1525,8 +1552,6 @@ int nbd_export_new(BlockExport *blk_exp,
         return size;
     }
 
-    assert(name && strlen(name) <= NBD_MAX_STRING_SIZE);
-
     /* Don't allow resize while the NBD server is running, otherwise we don't
      * care what happens with the node. */
     blk_get_perm(blk, &perm, &shared_perm);
@@ -1538,9 +1563,8 @@ int nbd_export_new(BlockExport *blk_exp,
     blk_set_allow_aio_context_change(blk, true);
 
     QTAILQ_INIT(&exp->clients);
-    exp->name = g_strdup(name);
-    assert(!desc || strlen(desc) <= NBD_MAX_STRING_SIZE);
-    exp->description = g_strdup(desc);
+    exp->name = g_strdup(arg->name);
+    exp->description = g_strdup(arg->description);
     exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH |
                      NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE);
     if (readonly) {
@@ -1554,12 +1578,12 @@ int nbd_export_new(BlockExport *blk_exp,
     }
     exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
 
-    if (bitmap) {
+    if (arg->bitmap) {
         BlockDriverState *bs = blk_bs(blk);
         BdrvDirtyBitmap *bm = NULL;
 
         while (bs) {
-            bm = bdrv_find_dirty_bitmap(bs, bitmap);
+            bm = bdrv_find_dirty_bitmap(bs, arg->bitmap);
             if (bm != NULL) {
                 break;
             }
@@ -1569,7 +1593,7 @@ int nbd_export_new(BlockExport *blk_exp,
 
         if (bm == NULL) {
             ret = -ENOENT;
-            error_setg(errp, "Bitmap '%s' is not found", bitmap);
+            error_setg(errp, "Bitmap '%s' is not found", arg->bitmap);
             goto fail;
         }
 
@@ -1583,15 +1607,15 @@ int nbd_export_new(BlockExport *blk_exp,
             ret = -EINVAL;
             error_setg(errp,
                        "Enabled bitmap '%s' incompatible with readonly export",
-                       bitmap);
+                       arg->bitmap);
             goto fail;
         }
 
         bdrv_dirty_bitmap_set_busy(bm, true);
         exp->export_bitmap = bm;
-        assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE);
+        assert(strlen(arg->bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE);
         exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s",
-                                                     bitmap);
+                                                     arg->bitmap);
         assert(strlen(exp->export_bitmap_context) < NBD_MAX_STRING_SIZE);
     }