1 /* 2 * Copyright (c) 2007 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #ifndef _SYS_SYSID_H_ 36 #define _SYS_SYSID_H_ 37 38 #include <sys/types.h> 39 40 /* 41 * SYSIDs are 64 bit entities and come in two varieties. Physical SYSIDs 42 * are used to efficiently route messages across the mesh, while Logical 43 * SYSIDs are persistently assigned identifiers representing specific devices 44 * or specific media or named filesystems. That is, the logical SYSID 45 * assigned to a filesystem or ANVIL partition can be stored in that 46 * filesystem's superblock and allows the filesystem to migrate or 47 * be multi-homed (have multiple physical SYSIDs representing the same 48 * logical entity). 49 * 50 * Physical SYSIDs can be ever-changing, and any given logical SYSID could 51 * in fact have multiple physical SYSIDs associated with it. The mesh is 52 * self-healing and the combination of the logical and physical sysid 53 * basically validates the message at the target and determines whether 54 * the physical SYSID must be recalculated (looked up again) or not. 55 */ 56 57 typedef u_int64_t sysid_t; 58 59 #endif 60