xref: /openbmc/linux/fs/efs/super.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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 super_block *s, struct kstatfs *buf);
19 static int efs_fill_super(struct super_block *s, void *d, int silent);
20 
21 static struct super_block *efs_get_sb(struct file_system_type *fs_type,
22 	int flags, const char *dev_name, void *data)
23 {
24 	return get_sb_bdev(fs_type, flags, dev_name, data, efs_fill_super);
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 kmem_cache_t * 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, SLAB_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, kmem_cache_t * cachep, unsigned long flags)
72 {
73 	struct efs_inode_info *ei = (struct efs_inode_info *) foo;
74 
75 	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
76 	    SLAB_CTOR_CONSTRUCTOR)
77 		inode_init_once(&ei->vfs_inode);
78 }
79 
80 static int init_inodecache(void)
81 {
82 	efs_inode_cachep = kmem_cache_create("efs_inode_cache",
83 				sizeof(struct efs_inode_info),
84 				0, SLAB_RECLAIM_ACCOUNT,
85 				init_once, NULL);
86 	if (efs_inode_cachep == NULL)
87 		return -ENOMEM;
88 	return 0;
89 }
90 
91 static void destroy_inodecache(void)
92 {
93 	if (kmem_cache_destroy(efs_inode_cachep))
94 		printk(KERN_INFO "efs_inode_cache: not all structures were freed\n");
95 }
96 
97 static void efs_put_super(struct super_block *s)
98 {
99 	kfree(s->s_fs_info);
100 	s->s_fs_info = NULL;
101 }
102 
103 static int efs_remount(struct super_block *sb, int *flags, char *data)
104 {
105 	*flags |= MS_RDONLY;
106 	return 0;
107 }
108 
109 static struct super_operations efs_superblock_operations = {
110 	.alloc_inode	= efs_alloc_inode,
111 	.destroy_inode	= efs_destroy_inode,
112 	.read_inode	= efs_read_inode,
113 	.put_super	= efs_put_super,
114 	.statfs		= efs_statfs,
115 	.remount_fs	= efs_remount,
116 };
117 
118 static struct export_operations efs_export_ops = {
119 	.get_parent	= efs_get_parent,
120 };
121 
122 static int __init init_efs_fs(void) {
123 	int err;
124 	printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
125 	err = init_inodecache();
126 	if (err)
127 		goto out1;
128 	err = register_filesystem(&efs_fs_type);
129 	if (err)
130 		goto out;
131 	return 0;
132 out:
133 	destroy_inodecache();
134 out1:
135 	return err;
136 }
137 
138 static void __exit exit_efs_fs(void) {
139 	unregister_filesystem(&efs_fs_type);
140 	destroy_inodecache();
141 }
142 
143 module_init(init_efs_fs)
144 module_exit(exit_efs_fs)
145 
146 static efs_block_t efs_validate_vh(struct volume_header *vh) {
147 	int		i;
148 	__be32		cs, *ui;
149 	int		csum;
150 	efs_block_t	sblock = 0; /* shuts up gcc */
151 	struct pt_types	*pt_entry;
152 	int		pt_type, slice = -1;
153 
154 	if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
155 		/*
156 		 * assume that we're dealing with a partition and allow
157 		 * read_super() to try and detect a valid superblock
158 		 * on the next block.
159 		 */
160 		return 0;
161 	}
162 
163 	ui = ((__be32 *) (vh + 1)) - 1;
164 	for(csum = 0; ui >= ((__be32 *) vh);) {
165 		cs = *ui--;
166 		csum += be32_to_cpu(cs);
167 	}
168 	if (csum) {
169 		printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
170 		return 0;
171 	}
172 
173 #ifdef DEBUG
174 	printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
175 
176 	for(i = 0; i < NVDIR; i++) {
177 		int	j;
178 		char	name[VDNAMESIZE+1];
179 
180 		for(j = 0; j < VDNAMESIZE; j++) {
181 			name[j] = vh->vh_vd[i].vd_name[j];
182 		}
183 		name[j] = (char) 0;
184 
185 		if (name[0]) {
186 			printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
187 				name,
188 				(int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
189 				(int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
190 		}
191 	}
192 #endif
193 
194 	for(i = 0; i < NPARTAB; i++) {
195 		pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
196 		for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
197 			if (pt_type == pt_entry->pt_type) break;
198 		}
199 #ifdef DEBUG
200 		if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
201 			printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
202 				i,
203 				(int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
204 				(int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
205 				pt_type,
206 				(pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
207 		}
208 #endif
209 		if (IS_EFS(pt_type)) {
210 			sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
211 			slice = i;
212 		}
213 	}
214 
215 	if (slice == -1) {
216 		printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
217 #ifdef DEBUG
218 	} else {
219 		printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
220 			slice,
221 			(pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
222 			sblock);
223 #endif
224 	}
225 	return(sblock);
226 }
227 
228 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
229 
230 	if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic))) return -1;
231 
232 	sb->fs_magic     = be32_to_cpu(super->fs_magic);
233 	sb->total_blocks = be32_to_cpu(super->fs_size);
234 	sb->first_block  = be32_to_cpu(super->fs_firstcg);
235 	sb->group_size   = be32_to_cpu(super->fs_cgfsize);
236 	sb->data_free    = be32_to_cpu(super->fs_tfree);
237 	sb->inode_free   = be32_to_cpu(super->fs_tinode);
238 	sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
239 	sb->total_groups = be16_to_cpu(super->fs_ncg);
240 
241 	return 0;
242 }
243 
244 static int efs_fill_super(struct super_block *s, void *d, int silent)
245 {
246 	struct efs_sb_info *sb;
247 	struct buffer_head *bh;
248 	struct inode *root;
249 
250  	sb = kmalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
251 	if (!sb)
252 		return -ENOMEM;
253 	s->s_fs_info = sb;
254 	memset(sb, 0, sizeof(struct efs_sb_info));
255 
256 	s->s_magic		= EFS_SUPER_MAGIC;
257 	if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
258 		printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
259 			EFS_BLOCKSIZE);
260 		goto out_no_fs_ul;
261 	}
262 
263 	/* read the vh (volume header) block */
264 	bh = sb_bread(s, 0);
265 
266 	if (!bh) {
267 		printk(KERN_ERR "EFS: cannot read volume header\n");
268 		goto out_no_fs_ul;
269 	}
270 
271 	/*
272 	 * if this returns zero then we didn't find any partition table.
273 	 * this isn't (yet) an error - just assume for the moment that
274 	 * the device is valid and go on to search for a superblock.
275 	 */
276 	sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
277 	brelse(bh);
278 
279 	if (sb->fs_start == -1) {
280 		goto out_no_fs_ul;
281 	}
282 
283 	bh = sb_bread(s, sb->fs_start + EFS_SUPER);
284 	if (!bh) {
285 		printk(KERN_ERR "EFS: cannot read superblock\n");
286 		goto out_no_fs_ul;
287 	}
288 
289 	if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
290 #ifdef DEBUG
291 		printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
292 #endif
293 		brelse(bh);
294 		goto out_no_fs_ul;
295 	}
296 	brelse(bh);
297 
298 	if (!(s->s_flags & MS_RDONLY)) {
299 #ifdef DEBUG
300 		printk(KERN_INFO "EFS: forcing read-only mode\n");
301 #endif
302 		s->s_flags |= MS_RDONLY;
303 	}
304 	s->s_op   = &efs_superblock_operations;
305 	s->s_export_op = &efs_export_ops;
306 	root = iget(s, EFS_ROOTINODE);
307 	s->s_root = d_alloc_root(root);
308 
309 	if (!(s->s_root)) {
310 		printk(KERN_ERR "EFS: get root inode failed\n");
311 		iput(root);
312 		goto out_no_fs;
313 	}
314 
315 	return 0;
316 
317 out_no_fs_ul:
318 out_no_fs:
319 	s->s_fs_info = NULL;
320 	kfree(sb);
321 	return -EINVAL;
322 }
323 
324 static int efs_statfs(struct super_block *s, struct kstatfs *buf) {
325 	struct efs_sb_info *sb = SUPER_INFO(s);
326 
327 	buf->f_type    = EFS_SUPER_MAGIC;	/* efs magic number */
328 	buf->f_bsize   = EFS_BLOCKSIZE;		/* blocksize */
329 	buf->f_blocks  = sb->total_groups *	/* total data blocks */
330 			(sb->group_size - sb->inode_blocks);
331 	buf->f_bfree   = sb->data_free;		/* free data blocks */
332 	buf->f_bavail  = sb->data_free;		/* free blocks for non-root */
333 	buf->f_files   = sb->total_groups *	/* total inodes */
334 			sb->inode_blocks *
335 			(EFS_BLOCKSIZE / sizeof(struct efs_dinode));
336 	buf->f_ffree   = sb->inode_free;	/* free inodes */
337 	buf->f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */
338 	buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
339 	buf->f_namelen = EFS_MAXNAMELEN;	/* max filename length */
340 
341 	return 0;
342 }
343 
344