summaryrefslogtreecommitdiffstats
path: root/fs/efs/super.c
blob: 04b5fe91d3c295ad283c361a92eb9b71c8625b8b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
/*
 * super.c
 *
 * Copyright (c) 1999 Al Smith
 *
 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/locks.h>
#include <linux/efs_fs.h>
#include <linux/efs_vh.h>
#include <linux/efs_fs_sb.h>

static DECLARE_FSTYPE_DEV(efs_fs_type, "efs", efs_read_super);

static struct super_operations efs_superblock_operations = {
	read_inode:	efs_read_inode,
	statfs:		efs_statfs,
};

static int __init init_efs_fs(void) {
	printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
	return register_filesystem(&efs_fs_type);
}

static void __exit exit_efs_fs(void) {
	unregister_filesystem(&efs_fs_type);
}

EXPORT_NO_SYMBOLS;

module_init(init_efs_fs)
module_exit(exit_efs_fs)

static efs_block_t efs_validate_vh(struct volume_header *vh) {
	int		i;
	unsigned int	cs, csum, *ui;
	efs_block_t	sblock = 0; /* shuts up gcc */
	struct pt_types	*pt_entry;
	int		pt_type, slice = -1;

	if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
		/*
		 * assume that we're dealing with a partition and allow
		 * read_super() to try and detect a valid superblock
		 * on the next block.
		 */
		return 0;
	}

	ui = ((unsigned int *) (vh + 1)) - 1;
	for(csum = 0; ui >= ((unsigned int *) vh);) {
		cs = *ui--;
		csum += be32_to_cpu(cs);
	}
	if (csum) {
		printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
		return 0;
	}

#ifdef DEBUG
	printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);

	for(i = 0; i < NVDIR; i++) {
		int	j;
		char	name[VDNAMESIZE+1];

		for(j = 0; j < VDNAMESIZE; j++) {
			name[j] = vh->vh_vd[i].vd_name[j];
		}
		name[j] = (char) 0;

		if (name[0]) {
			printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
				name,
				(int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
				(int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
		}
	}
#endif

	for(i = 0; i < NPARTAB; i++) {
		pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
		for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
			if (pt_type == pt_entry->pt_type) break;
		}
#ifdef DEBUG
		if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
			printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
				i,
				(int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
				(int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
				pt_type,
				(pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
		}
#endif
		if (IS_EFS(pt_type)) {
			sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
			slice = i;
		}
	}

	if (slice == -1) {
		printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
#ifdef DEBUG
	} else {
		printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
			slice,
			(pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
			sblock);
#endif
	}
	return(sblock);
}

static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {

	if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic))) return -1;

	sb->fs_magic     = be32_to_cpu(super->fs_magic);
	sb->total_blocks = be32_to_cpu(super->fs_size);
	sb->first_block  = be32_to_cpu(super->fs_firstcg);
	sb->group_size   = be32_to_cpu(super->fs_cgfsize);
	sb->data_free    = be32_to_cpu(super->fs_tfree);
	sb->inode_free   = be32_to_cpu(super->fs_tinode);
	sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
	sb->total_groups = be16_to_cpu(super->fs_ncg);
    
	return 0;    
}

struct super_block *efs_read_super(struct super_block *s, void *d, int silent) {
	kdev_t dev = s->s_dev;
	struct efs_sb_info *sb;
	struct buffer_head *bh;

 	sb = SUPER_INFO(s);

	set_blocksize(dev, EFS_BLOCKSIZE);
  
	/* read the vh (volume header) block */
	bh = bread(dev, 0, EFS_BLOCKSIZE);

	if (!bh) {
		printk(KERN_ERR "EFS: cannot read volume header\n");
		goto out_no_fs_ul;
	}

	/*
	 * if this returns zero then we didn't find any partition table.
	 * this isn't (yet) an error - just assume for the moment that
	 * the device is valid and go on to search for a superblock.
	 */
	sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
	brelse(bh);

	if (sb->fs_start == -1) {
		goto out_no_fs_ul;
	}

	bh = bread(dev, sb->fs_start + EFS_SUPER, EFS_BLOCKSIZE);
	if (!bh) {
		printk(KERN_ERR "EFS: cannot read superblock\n");
		goto out_no_fs_ul;
	}
		
	if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
#ifdef DEBUG
		printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
#endif
		brelse(bh);
		goto out_no_fs_ul;
	}
	brelse(bh);
 
	s->s_magic		= EFS_SUPER_MAGIC;
	s->s_blocksize		= EFS_BLOCKSIZE;
	s->s_blocksize_bits	= EFS_BLOCKSIZE_BITS;
	if (!(s->s_flags & MS_RDONLY)) {
#ifdef DEBUG
		printk(KERN_INFO "EFS: forcing read-only mode\n");
#endif
		s->s_flags |= MS_RDONLY;
	}
	s->s_op   = &efs_superblock_operations;
	s->s_root = d_alloc_root(iget(s, EFS_ROOTINODE));
 
	if (!(s->s_root)) {
		printk(KERN_ERR "EFS: get root inode failed\n");
		goto out_no_fs;
	}

	return(s);

out_no_fs_ul:
out_no_fs:
	return(NULL);
}

int efs_statfs(struct super_block *s, struct statfs *buf) {
	struct efs_sb_info *sb = SUPER_INFO(s);

	buf->f_type    = EFS_SUPER_MAGIC;	/* efs magic number */
	buf->f_bsize   = EFS_BLOCKSIZE;		/* blocksize */
	buf->f_blocks  = sb->total_groups *	/* total data blocks */
			(sb->group_size - sb->inode_blocks);
	buf->f_bfree   = sb->data_free;		/* free data blocks */
	buf->f_bavail  = sb->data_free;		/* free blocks for non-root */
	buf->f_files   = sb->total_groups *	/* total inodes */
			sb->inode_blocks *
			(EFS_BLOCKSIZE / sizeof(struct efs_dinode));
	buf->f_ffree   = sb->inode_free;	/* free inodes */
	buf->f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */
	buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
	buf->f_namelen = EFS_MAXNAMELEN;	/* max filename length */

	return 0;
}