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