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
18 #include "efs.h"
19 #include <linux/efs_vh.h>
20 #include <linux/efs_fs_sb.h>
21
22 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
23 static int efs_fill_super(struct super_block *s, void *d, int silent);
24
efs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)25 static struct dentry *efs_mount(struct file_system_type *fs_type,
26 int flags, const char *dev_name, void *data)
27 {
28 return mount_bdev(fs_type, flags, dev_name, data, efs_fill_super);
29 }
30
efs_kill_sb(struct super_block * s)31 static void efs_kill_sb(struct super_block *s)
32 {
33 struct efs_sb_info *sbi = SUPER_INFO(s);
34 kill_block_super(s);
35 kfree(sbi);
36 }
37
38 static struct file_system_type efs_fs_type = {
39 .owner = THIS_MODULE,
40 .name = "efs",
41 .mount = efs_mount,
42 .kill_sb = efs_kill_sb,
43 .fs_flags = FS_REQUIRES_DEV,
44 };
45 MODULE_ALIAS_FS("efs");
46
47 static struct pt_types sgi_pt_types[] = {
48 {0x00, "SGI vh"},
49 {0x01, "SGI trkrepl"},
50 {0x02, "SGI secrepl"},
51 {0x03, "SGI raw"},
52 {0x04, "SGI bsd"},
53 {SGI_SYSV, "SGI sysv"},
54 {0x06, "SGI vol"},
55 {SGI_EFS, "SGI efs"},
56 {0x08, "SGI lv"},
57 {0x09, "SGI rlv"},
58 {0x0A, "SGI xfs"},
59 {0x0B, "SGI xfslog"},
60 {0x0C, "SGI xlv"},
61 {0x82, "Linux swap"},
62 {0x83, "Linux native"},
63 {0, NULL}
64 };
65
66
67 static struct kmem_cache * efs_inode_cachep;
68
efs_alloc_inode(struct super_block * sb)69 static struct inode *efs_alloc_inode(struct super_block *sb)
70 {
71 struct efs_inode_info *ei;
72 ei = alloc_inode_sb(sb, efs_inode_cachep, GFP_KERNEL);
73 if (!ei)
74 return NULL;
75 return &ei->vfs_inode;
76 }
77
efs_free_inode(struct inode * inode)78 static void efs_free_inode(struct inode *inode)
79 {
80 kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
81 }
82
init_once(void * foo)83 static void init_once(void *foo)
84 {
85 struct efs_inode_info *ei = (struct efs_inode_info *) foo;
86
87 inode_init_once(&ei->vfs_inode);
88 }
89
init_inodecache(void)90 static int __init init_inodecache(void)
91 {
92 efs_inode_cachep = kmem_cache_create("efs_inode_cache",
93 sizeof(struct efs_inode_info), 0,
94 SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
95 SLAB_ACCOUNT, init_once);
96 if (efs_inode_cachep == NULL)
97 return -ENOMEM;
98 return 0;
99 }
100
destroy_inodecache(void)101 static void destroy_inodecache(void)
102 {
103 /*
104 * Make sure all delayed rcu free inodes are flushed before we
105 * destroy cache.
106 */
107 rcu_barrier();
108 kmem_cache_destroy(efs_inode_cachep);
109 }
110
efs_remount(struct super_block * sb,int * flags,char * data)111 static int efs_remount(struct super_block *sb, int *flags, char *data)
112 {
113 sync_filesystem(sb);
114 *flags |= SB_RDONLY;
115 return 0;
116 }
117
118 static const struct super_operations efs_superblock_operations = {
119 .alloc_inode = efs_alloc_inode,
120 .free_inode = efs_free_inode,
121 .statfs = efs_statfs,
122 .remount_fs = efs_remount,
123 };
124
125 static const struct export_operations efs_export_ops = {
126 .fh_to_dentry = efs_fh_to_dentry,
127 .fh_to_parent = efs_fh_to_parent,
128 .get_parent = efs_get_parent,
129 };
130
init_efs_fs(void)131 static 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;
141 out:
142 destroy_inodecache();
143 out1:
144 return err;
145 }
146
exit_efs_fs(void)147 static void __exit exit_efs_fs(void) {
148 unregister_filesystem(&efs_fs_type);
149 destroy_inodecache();
150 }
151
152 module_init(init_efs_fs)
module_exit(exit_efs_fs)153 module_exit(exit_efs_fs)
154
155 static 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
efs_validate_super(struct efs_sb_info * sb,struct efs_super * super)234 static 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
efs_fill_super(struct super_block * s,void * d,int silent)251 static int efs_fill_super(struct super_block *s, void *d, int silent)
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
efs_statfs(struct dentry * dentry,struct kstatfs * buf)330 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
331 struct super_block *sb = dentry->d_sb;
332 struct efs_sb_info *sbi = SUPER_INFO(sb);
333 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
334
335 buf->f_type = EFS_SUPER_MAGIC; /* efs magic number */
336 buf->f_bsize = EFS_BLOCKSIZE; /* blocksize */
337 buf->f_blocks = sbi->total_groups * /* total data blocks */
338 (sbi->group_size - sbi->inode_blocks);
339 buf->f_bfree = sbi->data_free; /* free data blocks */
340 buf->f_bavail = sbi->data_free; /* free blocks for non-root */
341 buf->f_files = sbi->total_groups * /* total inodes */
342 sbi->inode_blocks *
343 (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
344 buf->f_ffree = sbi->inode_free; /* free inodes */
345 buf->f_fsid = u64_to_fsid(id);
346 buf->f_namelen = EFS_MAXNAMELEN; /* max filename length */
347
348 return 0;
349 }
350
351