xref: /freebsd/lib/libufs/sblock.c (revision 193d9e768ba63fcfb187cfd17f461f7d41345048)
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 <stdlib.h>
44 #include <unistd.h>
45 
46 #include <libufs.h>
47 
48 static int superblocks[] = SBLOCKSEARCH;
49 
50 int
51 sbread(struct uufsd *disk)
52 {
53 	uint8_t block[MAXBSIZE];
54 	struct fs *fs;
55 	int sb, superblock;
56 	int i, size, blks;
57 	uint8_t *space;
58 
59 	ERROR(disk, NULL);
60 
61 	fs = &disk->d_fs;
62 	superblock = superblocks[0];
63 
64 	for (sb = 0; (superblock = superblocks[sb]) != -1; sb++) {
65 		if (bread(disk, superblock, disk->d_sb, SBLOCKSIZE) == -1) {
66 			ERROR(disk, "non-existent or truncated superblock");
67 			return (-1);
68 		}
69 		if (fs->fs_magic == FS_UFS1_MAGIC)
70 			disk->d_ufs = 1;
71 		if (fs->fs_magic == FS_UFS2_MAGIC &&
72 		    fs->fs_sblockloc == superblock)
73 			disk->d_ufs = 2;
74 		if (fs->fs_bsize <= MAXBSIZE &&
75 		    (size_t)fs->fs_bsize >= sizeof(*fs)) {
76 			if (disk->d_ufs)
77 				break;
78 		}
79 		disk->d_ufs = 0;
80 	}
81 	if (superblock == -1 || disk->d_ufs == 0) {
82 		/*
83 		 * Other error cases will result in errno being set, here we
84 		 * must set it to indicate no superblock could be found with
85 		 * which to associate this disk/filesystem.
86 		 */
87 		ERROR(disk, "no usable known superblock found");
88 		errno = ENOENT;
89 		return (-1);
90 	}
91 	disk->d_bsize = fs->fs_fsize / fsbtodb(fs, 1);
92 	disk->d_sblock = superblock / disk->d_bsize;
93 	/*
94 	 * Read in the superblock summary information.
95 	 */
96 	size = fs->fs_cssize;
97 	blks = howmany(size, fs->fs_fsize);
98 	size += fs->fs_ncg * sizeof(int32_t);
99 	space = malloc(size);
100 	if (space == NULL) {
101 		ERROR(disk, "failed to allocate space for summary information");
102 		return (-1);
103 	}
104 	fs->fs_csp = (struct csum *)space;
105 	for (i = 0; i < blks; i += fs->fs_frag) {
106 		size = fs->fs_bsize;
107 		if (i + fs->fs_frag > blks)
108 			size = (blks - i) * fs->fs_fsize;
109 		if (bread(disk, fsbtodb(fs, fs->fs_csaddr + i), block, size)
110 		    == -1) {
111 			ERROR(disk, "Failed to read sb summary information");
112 			free(fs->fs_csp);
113 			return (-1);
114 		}
115 		bcopy(block, space, size);
116 		space += size;
117 	}
118 	fs->fs_maxcluster = (uint32_t *)space;
119 	disk->d_sbcsum = fs->fs_csp;
120 
121 	return (0);
122 }
123 
124 int
125 sbwrite(struct uufsd *disk, int all)
126 {
127 	struct fs *fs;
128 	int blks, size;
129 	uint8_t *space;
130 	unsigned i;
131 
132 	ERROR(disk, NULL);
133 
134 	fs = &disk->d_fs;
135 
136 	if (!disk->d_sblock) {
137 		disk->d_sblock = disk->d_fs.fs_sblockloc / disk->d_bsize;
138 	}
139 
140 	if (bwrite(disk, disk->d_sblock, fs, SBLOCKSIZE) == -1) {
141 		ERROR(disk, "failed to write superblock");
142 		return (-1);
143 	}
144 	/*
145 	 * Write superblock summary information.
146 	 */
147 	blks = howmany(fs->fs_cssize, fs->fs_fsize);
148 	space = (uint8_t *)disk->d_sbcsum;
149 	for (i = 0; i < blks; i += fs->fs_frag) {
150 		size = fs->fs_bsize;
151 		if (i + fs->fs_frag > blks)
152 			size = (blks - i) * fs->fs_fsize;
153 		if (bwrite(disk, fsbtodb(fs, fs->fs_csaddr + i), space, size)
154 		    == -1) {
155 			ERROR(disk, "Failed to write sb summary information");
156 			return (-1);
157 		}
158 		space += size;
159 	}
160 	if (all) {
161 		for (i = 0; i < fs->fs_ncg; i++)
162 			if (bwrite(disk, fsbtodb(fs, cgsblock(fs, i)),
163 			    fs, SBLOCKSIZE) == -1) {
164 				ERROR(disk, "failed to update a superblock");
165 				return (-1);
166 			}
167 	}
168 	return (0);
169 }
170