nbd: Add qemu-nbd -D for human-readable description

[qemu.git] / nbd / server.c

diff --git a/nbd/server.c b/nbd/server.c
index 29e2099b5e367fe536229c55e36e9a1834101265..ac42391b45126559cb113d14357f527d61c47492 100644 (file)
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -61,14 +61,16 @@ struct NBDExport {
 
     BlockBackend *blk;
     char *name;
+    char *description;
     off_t dev_offset;
     off_t size;
-    uint32_t nbdflags;
+    uint16_t nbdflags;
     QTAILQ_HEAD(, NBDClient) clients;
     QTAILQ_ENTRY(NBDExport) next;
 
     AioContext *ctx;
 
+    BlockBackend *eject_notifier_blk;
     Notifier eject_notifier;
 };
 
@@ -128,7 +130,8 @@ static ssize_t nbd_negotiate_read(QIOChannel *ioc, void *buffer, size_t size)
 
 }
 
-static ssize_t nbd_negotiate_write(QIOChannel *ioc, void *buffer, size_t size)
+static ssize_t nbd_negotiate_write(QIOChannel *ioc, const void *buffer,
+                                   size_t size)
 {
     ssize_t ret;
     guint watch;
@@ -224,11 +227,15 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
 
 static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
 {
-    uint64_t magic, name_len;
+    uint64_t magic;
+    size_t name_len, desc_len;
     uint32_t opt, type, len;
+    const char *name = exp->name ? exp->name : "";
+    const char *desc = exp->description ? exp->description : "";
 
-    TRACE("Advertising export name '%s'", exp->name ? exp->name : "");
-    name_len = strlen(exp->name);
+    TRACE("Advertising export name '%s' description '%s'", name, desc);
+    name_len = strlen(name);
+    desc_len = strlen(desc);
     magic = cpu_to_be64(NBD_REP_MAGIC);
     if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
         LOG("write failed (magic)");
@@ -244,18 +251,22 @@ static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
         LOG("write failed (reply type)");
         return -EINVAL;
     }
-    len = cpu_to_be32(name_len + sizeof(len));
+    len = cpu_to_be32(name_len + desc_len + sizeof(len));
     if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
         LOG("write failed (length)");
         return -EINVAL;
     }
     len = cpu_to_be32(name_len);
     if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
-        LOG("write failed (length)");
+        LOG("write failed (name length)");
+        return -EINVAL;
+    }
+    if (nbd_negotiate_write(ioc, name, name_len) != name_len) {
+        LOG("write failed (name buffer)");
         return -EINVAL;
     }
-    if (nbd_negotiate_write(ioc, exp->name, name_len) != name_len) {
-        LOG("write failed (buffer)");
+    if (nbd_negotiate_write(ioc, desc, desc_len) != desc_len) {
+        LOG("write failed (description buffer)");
         return -EINVAL;
     }
     return 0;
@@ -348,6 +359,7 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
         return NULL;
     }
 
+    qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
     TRACE("Starting TLS handshake");
     data.loop = g_main_loop_new(g_main_context_default(), FALSE);
     qio_channel_tls_handshake(tioc,
@@ -544,8 +556,8 @@ static coroutine_fn int nbd_negotiate(NBDClientNewData *data)
     NBDClient *client = data->client;
     char buf[8 + 8 + 8 + 128];
     int rc;
-    const int myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
-                         NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);
+    const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
+                              NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);
     bool oldStyle;
 
     /* Old style negotiation header without options
@@ -575,7 +587,6 @@ static coroutine_fn int nbd_negotiate(NBDClientNewData *data)
 
     oldStyle = client->exp != NULL && !client->tlscreds;
     if (oldStyle) {
-        assert ((client->exp->nbdflags & ~65535) == 0);
         TRACE("advertising size %" PRIu64 " and flags %x",
               client->exp->size, client->exp->nbdflags | myflags);
         stq_be_p(buf + 8, NBD_CLIENT_MAGIC);
@@ -606,7 +617,6 @@ static coroutine_fn int nbd_negotiate(NBDClientNewData *data)
             goto fail;
         }
 
-        assert ((client->exp->nbdflags & ~65535) == 0);
         TRACE("advertising size %" PRIu64 " and flags %x",
               client->exp->size, client->exp->nbdflags | myflags);
         stq_be_p(buf + 18, client->exp->size);
@@ -809,11 +819,18 @@ static void nbd_eject_notifier(Notifier *n, void *data)
     nbd_export_close(exp);
 }
 
-NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
-                          uint32_t nbdflags, void (*close)(NBDExport *),
+NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
+                          uint16_t nbdflags, void (*close)(NBDExport *),
+                          bool writethrough, BlockBackend *on_eject_blk,
                           Error **errp)
 {
+    BlockBackend *blk;
     NBDExport *exp = g_malloc0(sizeof(NBDExport));
+
+    blk = blk_new();
+    blk_insert_bs(blk, bs);
+    blk_set_enable_write_cache(blk, !writethrough);
+
     exp->refcount = 1;
     QTAILQ_INIT(&exp->clients);
     exp->blk = blk;
@@ -829,11 +846,14 @@ NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
 
     exp->close = close;
     exp->ctx = blk_get_aio_context(blk);
-    blk_ref(blk);
     blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
 
-    exp->eject_notifier.notify = nbd_eject_notifier;
-    blk_add_remove_bs_notifier(blk, &exp->eject_notifier);
+    if (on_eject_blk) {
+        blk_ref(on_eject_blk);
+        exp->eject_notifier_blk = on_eject_blk;
+        exp->eject_notifier.notify = nbd_eject_notifier;
+        blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
+    }
 
     /*
      * NBD exports are used for non-shared storage migration.  Make sure
@@ -846,6 +866,7 @@ NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
     return exp;
 
 fail:
+    blk_unref(blk);
     g_free(exp);
     return NULL;
 }
@@ -883,6 +904,12 @@ void nbd_export_set_name(NBDExport *exp, const char *name)
     nbd_export_put(exp);
 }
 
+void nbd_export_set_description(NBDExport *exp, const char *description)
+{
+    g_free(exp->description);
+    exp->description = g_strdup(description);
+}
+
 void nbd_export_close(NBDExport *exp)
 {
     NBDClient *client, *next;
@@ -892,6 +919,7 @@ void nbd_export_close(NBDExport *exp)
         client_close(client);
     }
     nbd_export_set_name(exp, NULL);
+    nbd_export_set_description(exp, NULL);
     nbd_export_put(exp);
 }
 
@@ -910,13 +938,17 @@ void nbd_export_put(NBDExport *exp)
 
     if (--exp->refcount == 0) {
         assert(exp->name == NULL);
+        assert(exp->description == NULL);
 
         if (exp->close) {
             exp->close(exp);
         }
 
         if (exp->blk) {
-            notifier_remove(&exp->eject_notifier);
+            if (exp->eject_notifier_blk) {
+                notifier_remove(&exp->eject_notifier);
+                blk_unref(exp->eject_notifier_blk);
+            }
             blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
                                             blk_aio_detach, exp);
             blk_unref(exp->blk);
@@ -1057,7 +1089,8 @@ static ssize_t nbd_co_receive_request(NBDRequest *req,
     if (request->type & ~NBD_CMD_MASK_COMMAND & ~NBD_CMD_FLAG_FUA) {
         LOG("unsupported flags (got 0x%x)",
             request->type & ~NBD_CMD_MASK_COMMAND);
-        return -EINVAL;
+        rc = -EINVAL;
+        goto out;
     }
 
     rc = 0;