FreeBSD ZFS
The Zettabyte File System

uberblock.c

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00001 /*
00002  * CDDL HEADER START
00003  *
00004  * The contents of this file are subject to the terms of the
00005  * Common Development and Distribution License (the "License").
00006  * You may not use this file except in compliance with the License.
00007  *
00008  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
00009  * or http://www.opensolaris.org/os/licensing.
00010  * See the License for the specific language governing permissions
00011  * and limitations under the License.
00012  *
00013  * When distributing Covered Code, include this CDDL HEADER in each
00014  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
00015  * If applicable, add the following below this CDDL HEADER, with the
00016  * fields enclosed by brackets "[]" replaced with your own identifying
00017  * information: Portions Copyright [yyyy] [name of copyright owner]
00018  *
00019  * CDDL HEADER END
00020  */
00021 /*
00022  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
00023  */
00024 
00025 #include <sys/zfs_context.h>
00026 #include <sys/uberblock_impl.h>
00027 #include <sys/vdev_impl.h>
00028 
00029 int
00030 uberblock_verify(uberblock_t *ub)
00031 {
00032         if (ub->ub_magic == BSWAP_64((uint64_t)UBERBLOCK_MAGIC))
00033                 byteswap_uint64_array(ub, sizeof (uberblock_t));
00034 
00035         if (ub->ub_magic != UBERBLOCK_MAGIC)
00036                 return (EINVAL);
00037 
00038         return (0);
00039 }
00040 
00041 /*
00042  * Update the uberblock and return a boolean value indicating whether
00043  * anything changed in this transaction group.
00044  */
00045 int
00046 uberblock_update(uberblock_t *ub, vdev_t *rvd, uint64_t txg)
00047 {
00048         ASSERT(ub->ub_txg < txg);
00049 
00050         /*
00051          * We explicitly do not set ub_version here, so that older versions
00052          * continue to be written with the previous uberblock version.
00053          */
00054         ub->ub_magic = UBERBLOCK_MAGIC;
00055         ub->ub_txg = txg;
00056         ub->ub_guid_sum = rvd->vdev_guid_sum;
00057         ub->ub_timestamp = gethrestime_sec();
00058         ub->ub_software_version = SPA_VERSION;
00059 
00060         return (ub->ub_rootbp.blk_birth == txg);
00061 }
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