1// SPDX-License-Identifier: GPL-2.0
2/*
3 * super.c
4 *
5 * Copyright (c) 1999 Al Smith
6 *
7 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
8 */
9
10#include <linux/init.h>
11#include <linux/module.h>
12#include <linux/exportfs.h>
13#include <linux/slab.h>
14#include <linux/buffer_head.h>
15#include <linux/vfs.h>
16#include <linux/blkdev.h>
17#include <linux/fs_context.h>
18#include <linux/fs_parser.h>
19#include "efs.h"
20#include <linux/efs_vh.h>
21#include <linux/efs_fs_sb.h>
22
23static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
24static int efs_init_fs_context(struct fs_context *fc);
25
26static void efs_kill_sb(struct super_block *s)
27{
28	struct efs_sb_info *sbi = SUPER_INFO(s);
29	kill_block_super(s);
30	kfree(sbi);
31}
32
33static struct pt_types sgi_pt_types[] = {
34	{0x00,		"SGI vh"},
35	{0x01,		"SGI trkrepl"},
36	{0x02,		"SGI secrepl"},
37	{0x03,		"SGI raw"},
38	{0x04,		"SGI bsd"},
39	{SGI_SYSV,	"SGI sysv"},
40	{0x06,		"SGI vol"},
41	{SGI_EFS,	"SGI efs"},
42	{0x08,		"SGI lv"},
43	{0x09,		"SGI rlv"},
44	{0x0A,		"SGI xfs"},
45	{0x0B,		"SGI xfslog"},
46	{0x0C,		"SGI xlv"},
47	{0x82,		"Linux swap"},
48	{0x83,		"Linux native"},
49	{0,		NULL}
50};
51
52enum {
53	Opt_explicit_open,
54};
55
56static const struct fs_parameter_spec efs_param_spec[] = {
57	fsparam_flag    ("explicit-open",       Opt_explicit_open),
58	{}
59};
60
61/*
62 * File system definition and registration.
63 */
64static struct file_system_type efs_fs_type = {
65	.owner			= THIS_MODULE,
66	.name			= "efs",
67	.kill_sb		= efs_kill_sb,
68	.fs_flags		= FS_REQUIRES_DEV,
69	.init_fs_context	= efs_init_fs_context,
70	.parameters		= efs_param_spec,
71};
72MODULE_ALIAS_FS("efs");
73
74static struct kmem_cache * efs_inode_cachep;
75
76static struct inode *efs_alloc_inode(struct super_block *sb)
77{
78	struct efs_inode_info *ei;
79	ei = alloc_inode_sb(sb, efs_inode_cachep, GFP_KERNEL);
80	if (!ei)
81		return NULL;
82	return &ei->vfs_inode;
83}
84
85static void efs_free_inode(struct inode *inode)
86{
87	kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
88}
89
90static void init_once(void *foo)
91{
92	struct efs_inode_info *ei = (struct efs_inode_info *) foo;
93
94	inode_init_once(&ei->vfs_inode);
95}
96
97static int __init init_inodecache(void)
98{
99	efs_inode_cachep = kmem_cache_create("efs_inode_cache",
100				sizeof(struct efs_inode_info), 0,
101				SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
102				init_once);
103	if (efs_inode_cachep == NULL)
104		return -ENOMEM;
105	return 0;
106}
107
108static void destroy_inodecache(void)
109{
110	/*
111	 * Make sure all delayed rcu free inodes are flushed before we
112	 * destroy cache.
113	 */
114	rcu_barrier();
115	kmem_cache_destroy(efs_inode_cachep);
116}
117
118static const struct super_operations efs_superblock_operations = {
119	.alloc_inode	= efs_alloc_inode,
120	.free_inode	= efs_free_inode,
121	.statfs		= efs_statfs,
122};
123
124static const struct export_operations efs_export_ops = {
125	.encode_fh	= generic_encode_ino32_fh,
126	.fh_to_dentry	= efs_fh_to_dentry,
127	.fh_to_parent	= efs_fh_to_parent,
128	.get_parent	= efs_get_parent,
129};
130
131static int __init init_efs_fs(void) {
132	int err;
133	pr_info(EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
134	err = init_inodecache();
135	if (err)
136		goto out1;
137	err = register_filesystem(&efs_fs_type);
138	if (err)
139		goto out;
140	return 0;
141out:
142	destroy_inodecache();
143out1:
144	return err;
145}
146
147static void __exit exit_efs_fs(void) {
148	unregister_filesystem(&efs_fs_type);
149	destroy_inodecache();
150}
151
152module_init(init_efs_fs)
153module_exit(exit_efs_fs)
154
155static efs_block_t efs_validate_vh(struct volume_header *vh) {
156	int		i;
157	__be32		cs, *ui;
158	int		csum;
159	efs_block_t	sblock = 0; /* shuts up gcc */
160	struct pt_types	*pt_entry;
161	int		pt_type, slice = -1;
162
163	if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
164		/*
165		 * assume that we're dealing with a partition and allow
166		 * read_super() to try and detect a valid superblock
167		 * on the next block.
168		 */
169		return 0;
170	}
171
172	ui = ((__be32 *) (vh + 1)) - 1;
173	for(csum = 0; ui >= ((__be32 *) vh);) {
174		cs = *ui--;
175		csum += be32_to_cpu(cs);
176	}
177	if (csum) {
178		pr_warn("SGI disklabel: checksum bad, label corrupted\n");
179		return 0;
180	}
181
182#ifdef DEBUG
183	pr_debug("bf: \"%16s\"\n", vh->vh_bootfile);
184
185	for(i = 0; i < NVDIR; i++) {
186		int	j;
187		char	name[VDNAMESIZE+1];
188
189		for(j = 0; j < VDNAMESIZE; j++) {
190			name[j] = vh->vh_vd[i].vd_name[j];
191		}
192		name[j] = (char) 0;
193
194		if (name[0]) {
195			pr_debug("vh: %8s block: 0x%08x size: 0x%08x\n",
196				name, (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
197				(int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
198		}
199	}
200#endif
201
202	for(i = 0; i < NPARTAB; i++) {
203		pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
204		for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
205			if (pt_type == pt_entry->pt_type) break;
206		}
207#ifdef DEBUG
208		if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
209			pr_debug("pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
210				 i, (int)be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
211				 (int)be32_to_cpu(vh->vh_pt[i].pt_nblks),
212				 pt_type, (pt_entry->pt_name) ?
213				 pt_entry->pt_name : "unknown");
214		}
215#endif
216		if (IS_EFS(pt_type)) {
217			sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
218			slice = i;
219		}
220	}
221
222	if (slice == -1) {
223		pr_notice("partition table contained no EFS partitions\n");
224#ifdef DEBUG
225	} else {
226		pr_info("using slice %d (type %s, offset 0x%x)\n", slice,
227			(pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
228			sblock);
229#endif
230	}
231	return sblock;
232}
233
234static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
235
236	if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
237		return -1;
238
239	sb->fs_magic     = be32_to_cpu(super->fs_magic);
240	sb->total_blocks = be32_to_cpu(super->fs_size);
241	sb->first_block  = be32_to_cpu(super->fs_firstcg);
242	sb->group_size   = be32_to_cpu(super->fs_cgfsize);
243	sb->data_free    = be32_to_cpu(super->fs_tfree);
244	sb->inode_free   = be32_to_cpu(super->fs_tinode);
245	sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
246	sb->total_groups = be16_to_cpu(super->fs_ncg);
247
248	return 0;
249}
250
251static int efs_fill_super(struct super_block *s, struct fs_context *fc)
252{
253	struct efs_sb_info *sb;
254	struct buffer_head *bh;
255	struct inode *root;
256
257	sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
258	if (!sb)
259		return -ENOMEM;
260	s->s_fs_info = sb;
261	s->s_time_min = 0;
262	s->s_time_max = U32_MAX;
263
264	s->s_magic		= EFS_SUPER_MAGIC;
265	if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
266		pr_err("device does not support %d byte blocks\n",
267			EFS_BLOCKSIZE);
268		return -EINVAL;
269	}
270
271	/* read the vh (volume header) block */
272	bh = sb_bread(s, 0);
273
274	if (!bh) {
275		pr_err("cannot read volume header\n");
276		return -EIO;
277	}
278
279	/*
280	 * if this returns zero then we didn't find any partition table.
281	 * this isn't (yet) an error - just assume for the moment that
282	 * the device is valid and go on to search for a superblock.
283	 */
284	sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
285	brelse(bh);
286
287	if (sb->fs_start == -1) {
288		return -EINVAL;
289	}
290
291	bh = sb_bread(s, sb->fs_start + EFS_SUPER);
292	if (!bh) {
293		pr_err("cannot read superblock\n");
294		return -EIO;
295	}
296
297	if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
298#ifdef DEBUG
299		pr_warn("invalid superblock at block %u\n",
300			sb->fs_start + EFS_SUPER);
301#endif
302		brelse(bh);
303		return -EINVAL;
304	}
305	brelse(bh);
306
307	if (!sb_rdonly(s)) {
308#ifdef DEBUG
309		pr_info("forcing read-only mode\n");
310#endif
311		s->s_flags |= SB_RDONLY;
312	}
313	s->s_op   = &efs_superblock_operations;
314	s->s_export_op = &efs_export_ops;
315	root = efs_iget(s, EFS_ROOTINODE);
316	if (IS_ERR(root)) {
317		pr_err("get root inode failed\n");
318		return PTR_ERR(root);
319	}
320
321	s->s_root = d_make_root(root);
322	if (!(s->s_root)) {
323		pr_err("get root dentry failed\n");
324		return -ENOMEM;
325	}
326
327	return 0;
328}
329
330static void efs_free_fc(struct fs_context *fc)
331{
332	kfree(fc->fs_private);
333}
334
335static int efs_get_tree(struct fs_context *fc)
336{
337	return get_tree_bdev(fc, efs_fill_super);
338}
339
340static int efs_parse_param(struct fs_context *fc, struct fs_parameter *param)
341{
342	int token;
343	struct fs_parse_result result;
344
345	token = fs_parse(fc, efs_param_spec, param, &result);
346	if (token < 0)
347		return token;
348	return 0;
349}
350
351static int efs_reconfigure(struct fs_context *fc)
352{
353	sync_filesystem(fc->root->d_sb);
354
355	return 0;
356}
357
358struct efs_context {
359	unsigned long s_mount_opts;
360};
361
362static const struct fs_context_operations efs_context_opts = {
363	.parse_param	= efs_parse_param,
364	.get_tree	= efs_get_tree,
365	.reconfigure	= efs_reconfigure,
366	.free		= efs_free_fc,
367};
368
369/*
370 * Set up the filesystem mount context.
371 */
372static int efs_init_fs_context(struct fs_context *fc)
373{
374	struct efs_context *ctx;
375
376	ctx = kzalloc(sizeof(struct efs_context), GFP_KERNEL);
377	if (!ctx)
378		return -ENOMEM;
379	fc->fs_private = ctx;
380	fc->ops = &efs_context_opts;
381
382	return 0;
383}
384
385static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
386	struct super_block *sb = dentry->d_sb;
387	struct efs_sb_info *sbi = SUPER_INFO(sb);
388	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
389
390	buf->f_type    = EFS_SUPER_MAGIC;	/* efs magic number */
391	buf->f_bsize   = EFS_BLOCKSIZE;		/* blocksize */
392	buf->f_blocks  = sbi->total_groups *	/* total data blocks */
393			(sbi->group_size - sbi->inode_blocks);
394	buf->f_bfree   = sbi->data_free;	/* free data blocks */
395	buf->f_bavail  = sbi->data_free;	/* free blocks for non-root */
396	buf->f_files   = sbi->total_groups *	/* total inodes */
397			sbi->inode_blocks *
398			(EFS_BLOCKSIZE / sizeof(struct efs_dinode));
399	buf->f_ffree   = sbi->inode_free;	/* free inodes */
400	buf->f_fsid    = u64_to_fsid(id);
401	buf->f_namelen = EFS_MAXNAMELEN;	/* max filename length */
402
403	return 0;
404}
405
406