xref: /openbmc/linux/fs/efs/super.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  * super.c
3  *
4  * Copyright (c) 1999 Al Smith
5  *
6  * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
7  */
8 
9 #include <linux/init.h>
10 #include <linux/module.h>
11 #include <linux/efs_fs.h>
12 #include <linux/efs_vh.h>
13 #include <linux/efs_fs_sb.h>
14 #include <linux/slab.h>
15 #include <linux/buffer_head.h>
16 #include <linux/vfs.h>
17 
18 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
19 static int efs_fill_super(struct super_block *s, void *d, int silent);
20 
21 static int efs_get_sb(struct file_system_type *fs_type,
22 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
23 {
24 	return get_sb_bdev(fs_type, flags, dev_name, data, efs_fill_super, mnt);
25 }
26 
27 static struct file_system_type efs_fs_type = {
28 	.owner		= THIS_MODULE,
29 	.name		= "efs",
30 	.get_sb		= efs_get_sb,
31 	.kill_sb	= kill_block_super,
32 	.fs_flags	= FS_REQUIRES_DEV,
33 };
34 
35 static struct pt_types sgi_pt_types[] = {
36 	{0x00,		"SGI vh"},
37 	{0x01,		"SGI trkrepl"},
38 	{0x02,		"SGI secrepl"},
39 	{0x03,		"SGI raw"},
40 	{0x04,		"SGI bsd"},
41 	{SGI_SYSV,	"SGI sysv"},
42 	{0x06,		"SGI vol"},
43 	{SGI_EFS,	"SGI efs"},
44 	{0x08,		"SGI lv"},
45 	{0x09,		"SGI rlv"},
46 	{0x0A,		"SGI xfs"},
47 	{0x0B,		"SGI xfslog"},
48 	{0x0C,		"SGI xlv"},
49 	{0x82,		"Linux swap"},
50 	{0x83,		"Linux native"},
51 	{0,		NULL}
52 };
53 
54 
55 static struct kmem_cache * efs_inode_cachep;
56 
57 static struct inode *efs_alloc_inode(struct super_block *sb)
58 {
59 	struct efs_inode_info *ei;
60 	ei = (struct efs_inode_info *)kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
61 	if (!ei)
62 		return NULL;
63 	return &ei->vfs_inode;
64 }
65 
66 static void efs_destroy_inode(struct inode *inode)
67 {
68 	kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
69 }
70 
71 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
72 {
73 	struct efs_inode_info *ei = (struct efs_inode_info *) foo;
74 
75 	if (flags & SLAB_CTOR_CONSTRUCTOR)
76 		inode_init_once(&ei->vfs_inode);
77 }
78 
79 static int init_inodecache(void)
80 {
81 	efs_inode_cachep = kmem_cache_create("efs_inode_cache",
82 				sizeof(struct efs_inode_info),
83 				0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
84 				init_once, NULL);
85 	if (efs_inode_cachep == NULL)
86 		return -ENOMEM;
87 	return 0;
88 }
89 
90 static void destroy_inodecache(void)
91 {
92 	kmem_cache_destroy(efs_inode_cachep);
93 }
94 
95 static void efs_put_super(struct super_block *s)
96 {
97 	kfree(s->s_fs_info);
98 	s->s_fs_info = NULL;
99 }
100 
101 static int efs_remount(struct super_block *sb, int *flags, char *data)
102 {
103 	*flags |= MS_RDONLY;
104 	return 0;
105 }
106 
107 static const struct super_operations efs_superblock_operations = {
108 	.alloc_inode	= efs_alloc_inode,
109 	.destroy_inode	= efs_destroy_inode,
110 	.read_inode	= efs_read_inode,
111 	.put_super	= efs_put_super,
112 	.statfs		= efs_statfs,
113 	.remount_fs	= efs_remount,
114 };
115 
116 static struct export_operations efs_export_ops = {
117 	.get_parent	= efs_get_parent,
118 };
119 
120 static int __init init_efs_fs(void) {
121 	int err;
122 	printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
123 	err = init_inodecache();
124 	if (err)
125 		goto out1;
126 	err = register_filesystem(&efs_fs_type);
127 	if (err)
128 		goto out;
129 	return 0;
130 out:
131 	destroy_inodecache();
132 out1:
133 	return err;
134 }
135 
136 static void __exit exit_efs_fs(void) {
137 	unregister_filesystem(&efs_fs_type);
138 	destroy_inodecache();
139 }
140 
141 module_init(init_efs_fs)
142 module_exit(exit_efs_fs)
143 
144 static efs_block_t efs_validate_vh(struct volume_header *vh) {
145 	int		i;
146 	__be32		cs, *ui;
147 	int		csum;
148 	efs_block_t	sblock = 0; /* shuts up gcc */
149 	struct pt_types	*pt_entry;
150 	int		pt_type, slice = -1;
151 
152 	if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
153 		/*
154 		 * assume that we're dealing with a partition and allow
155 		 * read_super() to try and detect a valid superblock
156 		 * on the next block.
157 		 */
158 		return 0;
159 	}
160 
161 	ui = ((__be32 *) (vh + 1)) - 1;
162 	for(csum = 0; ui >= ((__be32 *) vh);) {
163 		cs = *ui--;
164 		csum += be32_to_cpu(cs);
165 	}
166 	if (csum) {
167 		printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
168 		return 0;
169 	}
170 
171 #ifdef DEBUG
172 	printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
173 
174 	for(i = 0; i < NVDIR; i++) {
175 		int	j;
176 		char	name[VDNAMESIZE+1];
177 
178 		for(j = 0; j < VDNAMESIZE; j++) {
179 			name[j] = vh->vh_vd[i].vd_name[j];
180 		}
181 		name[j] = (char) 0;
182 
183 		if (name[0]) {
184 			printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
185 				name,
186 				(int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
187 				(int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
188 		}
189 	}
190 #endif
191 
192 	for(i = 0; i < NPARTAB; i++) {
193 		pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
194 		for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
195 			if (pt_type == pt_entry->pt_type) break;
196 		}
197 #ifdef DEBUG
198 		if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
199 			printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
200 				i,
201 				(int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
202 				(int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
203 				pt_type,
204 				(pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
205 		}
206 #endif
207 		if (IS_EFS(pt_type)) {
208 			sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
209 			slice = i;
210 		}
211 	}
212 
213 	if (slice == -1) {
214 		printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
215 #ifdef DEBUG
216 	} else {
217 		printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
218 			slice,
219 			(pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
220 			sblock);
221 #endif
222 	}
223 	return sblock;
224 }
225 
226 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
227 
228 	if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
229 		return -1;
230 
231 	sb->fs_magic     = be32_to_cpu(super->fs_magic);
232 	sb->total_blocks = be32_to_cpu(super->fs_size);
233 	sb->first_block  = be32_to_cpu(super->fs_firstcg);
234 	sb->group_size   = be32_to_cpu(super->fs_cgfsize);
235 	sb->data_free    = be32_to_cpu(super->fs_tfree);
236 	sb->inode_free   = be32_to_cpu(super->fs_tinode);
237 	sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
238 	sb->total_groups = be16_to_cpu(super->fs_ncg);
239 
240 	return 0;
241 }
242 
243 static int efs_fill_super(struct super_block *s, void *d, int silent)
244 {
245 	struct efs_sb_info *sb;
246 	struct buffer_head *bh;
247 	struct inode *root;
248 
249  	sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
250 	if (!sb)
251 		return -ENOMEM;
252 	s->s_fs_info = sb;
253 
254 	s->s_magic		= EFS_SUPER_MAGIC;
255 	if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
256 		printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
257 			EFS_BLOCKSIZE);
258 		goto out_no_fs_ul;
259 	}
260 
261 	/* read the vh (volume header) block */
262 	bh = sb_bread(s, 0);
263 
264 	if (!bh) {
265 		printk(KERN_ERR "EFS: cannot read volume header\n");
266 		goto out_no_fs_ul;
267 	}
268 
269 	/*
270 	 * if this returns zero then we didn't find any partition table.
271 	 * this isn't (yet) an error - just assume for the moment that
272 	 * the device is valid and go on to search for a superblock.
273 	 */
274 	sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
275 	brelse(bh);
276 
277 	if (sb->fs_start == -1) {
278 		goto out_no_fs_ul;
279 	}
280 
281 	bh = sb_bread(s, sb->fs_start + EFS_SUPER);
282 	if (!bh) {
283 		printk(KERN_ERR "EFS: cannot read superblock\n");
284 		goto out_no_fs_ul;
285 	}
286 
287 	if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
288 #ifdef DEBUG
289 		printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
290 #endif
291 		brelse(bh);
292 		goto out_no_fs_ul;
293 	}
294 	brelse(bh);
295 
296 	if (!(s->s_flags & MS_RDONLY)) {
297 #ifdef DEBUG
298 		printk(KERN_INFO "EFS: forcing read-only mode\n");
299 #endif
300 		s->s_flags |= MS_RDONLY;
301 	}
302 	s->s_op   = &efs_superblock_operations;
303 	s->s_export_op = &efs_export_ops;
304 	root = iget(s, EFS_ROOTINODE);
305 	s->s_root = d_alloc_root(root);
306 
307 	if (!(s->s_root)) {
308 		printk(KERN_ERR "EFS: get root inode failed\n");
309 		iput(root);
310 		goto out_no_fs;
311 	}
312 
313 	return 0;
314 
315 out_no_fs_ul:
316 out_no_fs:
317 	s->s_fs_info = NULL;
318 	kfree(sb);
319 	return -EINVAL;
320 }
321 
322 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
323 	struct efs_sb_info *sb = SUPER_INFO(dentry->d_sb);
324 
325 	buf->f_type    = EFS_SUPER_MAGIC;	/* efs magic number */
326 	buf->f_bsize   = EFS_BLOCKSIZE;		/* blocksize */
327 	buf->f_blocks  = sb->total_groups *	/* total data blocks */
328 			(sb->group_size - sb->inode_blocks);
329 	buf->f_bfree   = sb->data_free;		/* free data blocks */
330 	buf->f_bavail  = sb->data_free;		/* free blocks for non-root */
331 	buf->f_files   = sb->total_groups *	/* total inodes */
332 			sb->inode_blocks *
333 			(EFS_BLOCKSIZE / sizeof(struct efs_dinode));
334 	buf->f_ffree   = sb->inode_free;	/* free inodes */
335 	buf->f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */
336 	buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
337 	buf->f_namelen = EFS_MAXNAMELEN;	/* max filename length */
338 
339 	return 0;
340 }
341 
342