afs: Implement client support for the YFSVL.GetCellName RPC op
Implement client support for the YFSVL.GetCellName RPC operation by which
YFS permits the canonical cell name to be queried from a VL server.
Signed-off-by: David Howells <[email protected]>
diff --git a/fs/afs/vlclient.c b/fs/afs/vlclient.c
index d0c8562..fd82850 100644
--- a/fs/afs/vlclient.c
+++ b/fs/afs/vlclient.c
@@ -645,3 +645,114 @@ struct afs_addr_list *afs_yfsvl_get_endpoints(struct afs_vl_cursor *vc,
afs_make_call(&vc->ac, call, GFP_KERNEL);
return (struct afs_addr_list *)afs_wait_for_call_to_complete(call, &vc->ac);
}
+
+/*
+ * Deliver reply data to a YFSVL.GetCellName operation.
+ */
+static int afs_deliver_yfsvl_get_cell_name(struct afs_call *call)
+{
+ char *cell_name;
+ u32 namesz, paddedsz;
+ int ret;
+
+ _enter("{%u,%zu/%u}",
+ call->unmarshall, iov_iter_count(call->iter), call->count);
+
+ switch (call->unmarshall) {
+ case 0:
+ afs_extract_to_tmp(call);
+ call->unmarshall++;
+
+ /* Fall through - and extract the cell name length */
+ case 1:
+ ret = afs_extract_data(call, true);
+ if (ret < 0)
+ return ret;
+
+ namesz = ntohl(call->tmp);
+ if (namesz > AFS_MAXCELLNAME)
+ return afs_protocol_error(call, afs_eproto_cellname_len);
+ paddedsz = (namesz + 3) & ~3;
+ call->count = namesz;
+ call->count2 = paddedsz - namesz;
+
+ cell_name = kmalloc(namesz + 1, GFP_KERNEL);
+ if (!cell_name)
+ return -ENOMEM;
+ cell_name[namesz] = 0;
+ call->ret_str = cell_name;
+
+ afs_extract_begin(call, cell_name, namesz);
+ call->unmarshall++;
+
+ /* Fall through - and extract cell name */
+ case 2:
+ ret = afs_extract_data(call, true);
+ if (ret < 0)
+ return ret;
+
+ afs_extract_discard(call, call->count2);
+ call->unmarshall++;
+
+ /* Fall through - and extract padding */
+ case 3:
+ ret = afs_extract_data(call, false);
+ if (ret < 0)
+ return ret;
+
+ call->unmarshall++;
+ break;
+ }
+
+ _leave(" = 0 [done]");
+ return 0;
+}
+
+static void afs_destroy_yfsvl_get_cell_name(struct afs_call *call)
+{
+ kfree(call->ret_str);
+ afs_flat_call_destructor(call);
+}
+
+/*
+ * VL.GetCapabilities operation type
+ */
+static const struct afs_call_type afs_YFSVLGetCellName = {
+ .name = "YFSVL.GetCellName",
+ .op = afs_YFSVL_GetCellName,
+ .deliver = afs_deliver_yfsvl_get_cell_name,
+ .destructor = afs_destroy_yfsvl_get_cell_name,
+};
+
+/*
+ * Probe a volume server for the capabilities that it supports. This can
+ * return up to 196 words.
+ *
+ * We use this to probe for service upgrade to determine what the server at the
+ * other end supports.
+ */
+char *afs_yfsvl_get_cell_name(struct afs_vl_cursor *vc)
+{
+ struct afs_call *call;
+ struct afs_net *net = vc->cell->net;
+ __be32 *bp;
+
+ _enter("");
+
+ call = afs_alloc_flat_call(net, &afs_YFSVLGetCellName, 1 * 4, 0);
+ if (!call)
+ return ERR_PTR(-ENOMEM);
+
+ call->key = vc->key;
+ call->ret_str = NULL;
+ call->max_lifespan = AFS_VL_MAX_LIFESPAN;
+
+ /* marshall the parameters */
+ bp = call->request;
+ *bp++ = htonl(YVLGETCELLNAME);
+
+ /* Can't take a ref on server */
+ trace_afs_make_vl_call(call);
+ afs_make_call(&vc->ac, call, GFP_KERNEL);
+ return (char *)afs_wait_for_call_to_complete(call, &vc->ac);
+}
