xref: /freebsd/lib/libufs/sblock.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
1 /*
2  * Copyright (c) 2002 Juli Mallett.  All rights reserved.
3  *
4  * This software was written by Juli Mallett <jmallett@FreeBSD.org> for the
5  * FreeBSD project.  Redistribution and use in source and binary forms, with
6  * or without modification, are permitted provided that the following
7  * conditions are met:
8  *
9  * 1. Redistribution of source code must retain the above copyright notice,
10  *    this list of conditions and the following disclaimer.
11  * 2. Redistribution in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
19  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
20  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
23  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
24  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25  * POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include <sys/param.h>
32 #include <sys/mount.h>
33 #include <sys/disklabel.h>
34 #include <sys/stat.h>
35 
36 #include <ufs/ufs/ufsmount.h>
37 #include <ufs/ufs/dinode.h>
38 #include <ufs/ffs/fs.h>
39 
40 #include <errno.h>
41 #include <stdio.h>
42 #include <string.h>
43 #include <unistd.h>
44 
45 #include <libufs.h>
46 
47 static int superblocks[] = SBLOCKSEARCH;
48 
49 int
50 sbread(struct uufsd *disk)
51 {
52 	struct fs *fs;
53 	int sb, superblock;
54 
55 	ERROR(disk, NULL);
56 
57 	fs = &disk->d_fs;
58 	superblock = superblocks[0];
59 
60 	for (sb = 0; (superblock = superblocks[sb]) != -1; sb++) {
61 		if (bread(disk, superblock, disk->d_sb, SBLOCKSIZE) == -1) {
62 			ERROR(disk, "non-existent or truncated superblock");
63 			return (-1);
64 		}
65 		if (fs->fs_magic == FS_UFS1_MAGIC)
66 			disk->d_ufs = 1;
67 		if (fs->fs_magic == FS_UFS2_MAGIC &&
68 		    fs->fs_sblockloc == superblock)
69 			disk->d_ufs = 2;
70 		if (fs->fs_bsize <= MAXBSIZE &&
71 		    (size_t)fs->fs_bsize >= sizeof(*fs)) {
72 			if (disk->d_ufs)
73 				break;
74 		}
75 		disk->d_ufs = 0;
76 	}
77 	if (superblock == -1 || disk->d_ufs == 0) {
78 		/*
79 		 * Other error cases will result in errno being set, here we
80 		 * must set it to indicate no superblock could be found with
81 		 * which to associate this disk/filesystem.
82 		 */
83 		ERROR(disk, "no usable known superblock found");
84 		errno = ENOENT;
85 		return (-1);
86 	}
87 	disk->d_bsize = fs->fs_fsize / fsbtodb(fs, 1);
88 	disk->d_sblock = superblock / disk->d_bsize;
89 	return (0);
90 }
91 
92 int
93 sbwrite(struct uufsd *disk, int all)
94 {
95 	struct fs *fs;
96 	int i;
97 
98 	ERROR(disk, NULL);
99 
100 	fs = &disk->d_fs;
101 
102 	if (!disk->d_sblock) {
103 		disk->d_sblock = disk->d_fs.fs_sblockloc / disk->d_bsize;
104 	}
105 
106 	if (bwrite(disk, disk->d_sblock, fs, SBLOCKSIZE) == -1) {
107 		ERROR(disk, "failed to write superblock");
108 		return (-1);
109 	}
110 	if (all) {
111 		for (i = 0; i < fs->fs_ncg; i++)
112 			if (bwrite(disk, fsbtodb(fs, cgsblock(fs, i)),
113 			    fs, SBLOCKSIZE) == -1) {
114 				ERROR(disk, "failed to update a superblock");
115 				return (-1);
116 			}
117 	}
118 	return (0);
119 }
120