block/rbd: Add support for ceph namespaces

Starting from ceph Nautilus, RBD has support for namespaces, allowing
for finer grain ACLs on images inside a pool, and tenant isolation.

In the rbd cli tool documentation, the new image-spec and snap-spec are :
 - [pool-name/[namespace-name/]]image-name
 - [pool-name/[namespace-name/]]image-name@snap-name

When using an non namespace's enabled qemu, it complains about not
finding the image called namespace-name/image-name, thus we only need to
parse the image once again to find if there is a '/' in its name, and if
there is, use what is before it as the name of the namespace to later
pass it to rados_ioctx_set_namespace.
rados_ioctx_set_namespace if called with en empty string or a null
pointer as the namespace parameters pretty much does nothing, as it then
defaults to the default namespace.

The namespace is extracted inside qemu_rbd_parse_filename, stored in the
qdict, and used in qemu_rbd_connect to make it work with both qemu-img,
and qemu itself.

Signed-off-by: Florian Florensa <fflorensa@online.net>
Message-Id: <20200110111513.321728-2-fflorensa@online.net>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/rbd.c

@@ -104,6 +104,7 @@ typedef struct BDRVRBDState {
     rbd_image_t image;
     char *image_name;
     char *snap;
+    char *namespace;
     uint64_t image_size;
 } BDRVRBDState;
 
@@ -152,7 +153,7 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options,
     const char *start;
     char *p, *buf;
     QList *keypairs = NULL;
-    char *found_str;
+    char *found_str, *image_name;
 
     if (!strstart(filename, "rbd:", &start)) {
         error_setg(errp, "File name must start with 'rbd:'");
@@ -171,18 +172,24 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options,
     qdict_put_str(options, "pool", found_str);
 
     if (strchr(p, '@')) {
-        found_str = qemu_rbd_next_tok(p, '@', &p);
-        qemu_rbd_unescape(found_str);
-        qdict_put_str(options, "image", found_str);
+        image_name = qemu_rbd_next_tok(p, '@', &p);
 
         found_str = qemu_rbd_next_tok(p, ':', &p);
         qemu_rbd_unescape(found_str);
         qdict_put_str(options, "snapshot", found_str);
     } else {
-        found_str = qemu_rbd_next_tok(p, ':', &p);
-        qemu_rbd_unescape(found_str);
-        qdict_put_str(options, "image", found_str);
+        image_name = qemu_rbd_next_tok(p, ':', &p);
     }
+    /* Check for namespace in the image_name */
+    if (strchr(image_name, '/')) {
+        found_str = qemu_rbd_next_tok(image_name, '/', &image_name);
+        qemu_rbd_unescape(found_str);
+        qdict_put_str(options, "namespace", found_str);
+    } else {
+        qdict_put_str(options, "namespace", "");
+    }
+    qemu_rbd_unescape(image_name);
+    qdict_put_str(options, "image", image_name);
     if (!p) {
         goto done;
     }
@@ -343,6 +350,11 @@ static QemuOptsList runtime_opts = {
             .type = QEMU_OPT_STRING,
             .help = "Rados pool name",
         },
+        {
+            .name = "namespace",
+            .type = QEMU_OPT_STRING,
+            .help = "Rados namespace name in the pool",
+        },
         {
             .name = "image",
             .type = QEMU_OPT_STRING,
@@ -467,13 +479,14 @@ static int coroutine_fn qemu_rbd_co_create_opts(const char *filename,
      * schema, but when they come from -drive, they're all QString.
      */
     loc = rbd_opts->location;
-    loc->pool     = g_strdup(qdict_get_try_str(options, "pool"));
-    loc->conf     = g_strdup(qdict_get_try_str(options, "conf"));
-    loc->has_conf = !!loc->conf;
-    loc->user     = g_strdup(qdict_get_try_str(options, "user"));
-    loc->has_user = !!loc->user;
-    loc->image    = g_strdup(qdict_get_try_str(options, "image"));
-    keypairs      = qdict_get_try_str(options, "=keyvalue-pairs");
+    loc->pool        = g_strdup(qdict_get_try_str(options, "pool"));
+    loc->conf        = g_strdup(qdict_get_try_str(options, "conf"));
+    loc->has_conf    = !!loc->conf;
+    loc->user        = g_strdup(qdict_get_try_str(options, "user"));
+    loc->has_user    = !!loc->user;
+    loc->q_namespace = g_strdup(qdict_get_try_str(options, "namespace"));
+    loc->image       = g_strdup(qdict_get_try_str(options, "image"));
+    keypairs         = qdict_get_try_str(options, "=keyvalue-pairs");
 
     ret = qemu_rbd_do_create(create_options, keypairs, password_secret, errp);
     if (ret < 0) {
@@ -648,6 +661,11 @@ static int qemu_rbd_connect(rados_t *cluster, rados_ioctx_t *io_ctx,
         error_setg_errno(errp, -r, "error opening pool %s", opts->pool);
         goto failed_shutdown;
     }
+    /*
+     * Set the namespace after opening the io context on the pool,
+     * if nspace == NULL or if nspace == "", it is just as we did nothing
+     */
+    rados_ioctx_set_namespace(*io_ctx, opts->q_namespace);
 
     return 0;
 

qapi/block-core.json

@@ -3544,6 +3544,8 @@
 #
 # @pool: Ceph pool name.
 #
+# @namespace: Rados namespace name in the Ceph pool. (Since 5.0)
+#
 # @image: Image name in the Ceph pool.
 #
 # @conf: path to Ceph configuration file.  Values
@@ -3570,6 +3572,7 @@
 ##
 { 'struct': 'BlockdevOptionsRbd',
   'data': { 'pool': 'str',
+            '*namespace': 'str',
             'image': 'str',
             '*conf': 'str',
             '*snapshot': 'str',