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
17 #include "efs.h"
18 #include <linux/efs_vh.h>
19 #include <linux/efs_fs_sb.h>
20
21 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
22 static int efs_fill_super(struct super_block *s, void *d, int silent);
23
efs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)24 static struct dentry *efs_mount(struct file_system_type *fs_type,
25 int flags, const char *dev_name, void *data)
26 {
27 return mount_bdev(fs_type, flags, dev_name, data, efs_fill_super);
28 }
29
efs_kill_sb(struct super_block * s)30 static void efs_kill_sb(struct super_block *s)
31 {
32 struct efs_sb_info *sbi = SUPER_INFO(s);
33 kill_block_super(s);
34 kfree(sbi);
35 }
36
37 static struct file_system_type efs_fs_type = {
38 .owner = THIS_MODULE,
39 .name = "efs",
40 .mount = efs_mount,
41 .kill_sb = efs_kill_sb,
42 .fs_flags = FS_REQUIRES_DEV,
43 };
44 MODULE_ALIAS_FS("efs");
45
46 static struct pt_types sgi_pt_types[] = {
47 {0x00, "SGI vh"},
48 {0x01, "SGI trkrepl"},
49 {0x02, "SGI secrepl"},
50 {0x03, "SGI raw"},
51 {0x04, "SGI bsd"},
52 {SGI_SYSV, "SGI sysv"},
53 {0x06, "SGI vol"},
54 {SGI_EFS, "SGI efs"},
55 {0x08, "SGI lv"},
56 {0x09, "SGI rlv"},
57 {0x0A, "SGI xfs"},
58 {0x0B, "SGI xfslog"},
59 {0x0C, "SGI xlv"},
60 {0x82, "Linux swap"},
61 {0x83, "Linux native"},
62 {0, NULL}
63 };
64
65
66 static struct kmem_cache * efs_inode_cachep;
67
efs_alloc_inode(struct super_block * sb)68 static struct inode *efs_alloc_inode(struct super_block *sb)
69 {
70 struct efs_inode_info *ei;
71 ei = kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
72 if (!ei)
73 return NULL;
74 return &ei->vfs_inode;
75 }
76
efs_free_inode(struct inode * inode)77 static void efs_free_inode(struct inode *inode)
78 {
79 kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
80 }
81
init_once(void * foo)82 static void init_once(void *foo)
83 {
84 struct efs_inode_info *ei = (struct efs_inode_info *) foo;
85
86 inode_init_once(&ei->vfs_inode);
87 }
88
init_inodecache(void)89 static int __init init_inodecache(void)
90 {
91 efs_inode_cachep = kmem_cache_create("efs_inode_cache",
92 sizeof(struct efs_inode_info), 0,
93 SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
94 SLAB_ACCOUNT, init_once);
95 if (efs_inode_cachep == NULL)
96 return -ENOMEM;
97 return 0;
98 }
99
destroy_inodecache(void)100 static void destroy_inodecache(void)
101 {
102 /*
103 * Make sure all delayed rcu free inodes are flushed before we
104 * destroy cache.
105 */
106 rcu_barrier();
107 kmem_cache_destroy(efs_inode_cachep);
108 }
109
efs_remount(struct super_block * sb,int * flags,char * data)110 static int efs_remount(struct super_block *sb, int *flags, char *data)
111 {
112 sync_filesystem(sb);
113 *flags |= SB_RDONLY;
114 return 0;
115 }
116
117 static const struct super_operations efs_superblock_operations = {
118 .alloc_inode = efs_alloc_inode,
119 .free_inode = efs_free_inode,
120 .statfs = efs_statfs,
121 .remount_fs = efs_remount,
122 };
123
124 static const struct export_operations efs_export_ops = {
125 .fh_to_dentry = efs_fh_to_dentry,
126 .fh_to_parent = efs_fh_to_parent,
127 .get_parent = efs_get_parent,
128 };
129
init_efs_fs(void)130 static int __init init_efs_fs(void) {
131 int err;
132 pr_info(EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
133 err = init_inodecache();
134 if (err)
135 goto out1;
136 err = register_filesystem(&efs_fs_type);
137 if (err)
138 goto out;
139 return 0;
140 out:
141 destroy_inodecache();
142 out1:
143 return err;
144 }
145
exit_efs_fs(void)146 static void __exit exit_efs_fs(void) {
147 unregister_filesystem(&efs_fs_type);
148 destroy_inodecache();
149 }
150
151 module_init(init_efs_fs)
module_exit(exit_efs_fs)152 module_exit(exit_efs_fs)
153
154 static efs_block_t efs_validate_vh(struct volume_header *vh) {
155 int i;
156 __be32 cs, *ui;
157 int csum;
158 efs_block_t sblock = 0; /* shuts up gcc */
159 struct pt_types *pt_entry;
160 int pt_type, slice = -1;
161
162 if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
163 /*
164 * assume that we're dealing with a partition and allow
165 * read_super() to try and detect a valid superblock
166 * on the next block.
167 */
168 return 0;
169 }
170
171 ui = ((__be32 *) (vh + 1)) - 1;
172 for(csum = 0; ui >= ((__be32 *) vh);) {
173 cs = *ui--;
174 csum += be32_to_cpu(cs);
175 }
176 if (csum) {
177 pr_warn("SGI disklabel: checksum bad, label corrupted\n");
178 return 0;
179 }
180
181 #ifdef DEBUG
182 pr_debug("bf: \"%16s\"\n", vh->vh_bootfile);
183
184 for(i = 0; i < NVDIR; i++) {
185 int j;
186 char name[VDNAMESIZE+1];
187
188 for(j = 0; j < VDNAMESIZE; j++) {
189 name[j] = vh->vh_vd[i].vd_name[j];
190 }
191 name[j] = (char) 0;
192
193 if (name[0]) {
194 pr_debug("vh: %8s block: 0x%08x size: 0x%08x\n",
195 name, (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
196 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
197 }
198 }
199 #endif
200
201 for(i = 0; i < NPARTAB; i++) {
202 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
203 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
204 if (pt_type == pt_entry->pt_type) break;
205 }
206 #ifdef DEBUG
207 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
208 pr_debug("pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
209 i, (int)be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
210 (int)be32_to_cpu(vh->vh_pt[i].pt_nblks),
211 pt_type, (pt_entry->pt_name) ?
212 pt_entry->pt_name : "unknown");
213 }
214 #endif
215 if (IS_EFS(pt_type)) {
216 sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
217 slice = i;
218 }
219 }
220
221 if (slice == -1) {
222 pr_notice("partition table contained no EFS partitions\n");
223 #ifdef DEBUG
224 } else {
225 pr_info("using slice %d (type %s, offset 0x%x)\n", slice,
226 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
227 sblock);
228 #endif
229 }
230 return sblock;
231 }
232
efs_validate_super(struct efs_sb_info * sb,struct efs_super * super)233 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
234
235 if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
236 return -1;
237
238 sb->fs_magic = be32_to_cpu(super->fs_magic);
239 sb->total_blocks = be32_to_cpu(super->fs_size);
240 sb->first_block = be32_to_cpu(super->fs_firstcg);
241 sb->group_size = be32_to_cpu(super->fs_cgfsize);
242 sb->data_free = be32_to_cpu(super->fs_tfree);
243 sb->inode_free = be32_to_cpu(super->fs_tinode);
244 sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
245 sb->total_groups = be16_to_cpu(super->fs_ncg);
246
247 return 0;
248 }
249
efs_fill_super(struct super_block * s,void * d,int silent)250 static int efs_fill_super(struct super_block *s, void *d, int silent)
251 {
252 struct efs_sb_info *sb;
253 struct buffer_head *bh;
254 struct inode *root;
255
256 sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
257 if (!sb)
258 return -ENOMEM;
259 s->s_fs_info = sb;
260 s->s_time_min = 0;
261 s->s_time_max = U32_MAX;
262
263 s->s_magic = EFS_SUPER_MAGIC;
264 if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
265 pr_err("device does not support %d byte blocks\n",
266 EFS_BLOCKSIZE);
267 return -EINVAL;
268 }
269
270 /* read the vh (volume header) block */
271 bh = sb_bread(s, 0);
272
273 if (!bh) {
274 pr_err("cannot read volume header\n");
275 return -EIO;
276 }
277
278 /*
279 * if this returns zero then we didn't find any partition table.
280 * this isn't (yet) an error - just assume for the moment that
281 * the device is valid and go on to search for a superblock.
282 */
283 sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
284 brelse(bh);
285
286 if (sb->fs_start == -1) {
287 return -EINVAL;
288 }
289
290 bh = sb_bread(s, sb->fs_start + EFS_SUPER);
291 if (!bh) {
292 pr_err("cannot read superblock\n");
293 return -EIO;
294 }
295
296 if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
297 #ifdef DEBUG
298 pr_warn("invalid superblock at block %u\n",
299 sb->fs_start + EFS_SUPER);
300 #endif
301 brelse(bh);
302 return -EINVAL;
303 }
304 brelse(bh);
305
306 if (!sb_rdonly(s)) {
307 #ifdef DEBUG
308 pr_info("forcing read-only mode\n");
309 #endif
310 s->s_flags |= SB_RDONLY;
311 }
312 s->s_op = &efs_superblock_operations;
313 s->s_export_op = &efs_export_ops;
314 root = efs_iget(s, EFS_ROOTINODE);
315 if (IS_ERR(root)) {
316 pr_err("get root inode failed\n");
317 return PTR_ERR(root);
318 }
319
320 s->s_root = d_make_root(root);
321 if (!(s->s_root)) {
322 pr_err("get root dentry failed\n");
323 return -ENOMEM;
324 }
325
326 return 0;
327 }
328
efs_statfs(struct dentry * dentry,struct kstatfs * buf)329 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
330 struct super_block *sb = dentry->d_sb;
331 struct efs_sb_info *sbi = SUPER_INFO(sb);
332 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
333
334 buf->f_type = EFS_SUPER_MAGIC; /* efs magic number */
335 buf->f_bsize = EFS_BLOCKSIZE; /* blocksize */
336 buf->f_blocks = sbi->total_groups * /* total data blocks */
337 (sbi->group_size - sbi->inode_blocks);
338 buf->f_bfree = sbi->data_free; /* free data blocks */
339 buf->f_bavail = sbi->data_free; /* free blocks for non-root */
340 buf->f_files = sbi->total_groups * /* total inodes */
341 sbi->inode_blocks *
342 (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
343 buf->f_ffree = sbi->inode_free; /* free inodes */
344 buf->f_fsid.val[0] = (u32)id;
345 buf->f_fsid.val[1] = (u32)(id >> 32);
346 buf->f_namelen = EFS_MAXNAMELEN; /* max filename length */
347
348 return 0;
349 }
350
351