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
22static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
23static int efs_fill_super(struct super_block *s, void *d, int silent);
24
25static 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, fill_super: efs_fill_super);
29}
30
31static void efs_kill_sb(struct super_block *s)
32{
33 struct efs_sb_info *sbi = SUPER_INFO(sb: s);
34 kill_block_super(sb: s);
35 kfree(objp: sbi);
36}
37
38static 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};
45MODULE_ALIAS_FS("efs");
46
47static 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
67static struct kmem_cache * efs_inode_cachep;
68
69static struct inode *efs_alloc_inode(struct super_block *sb)
70{
71 struct efs_inode_info *ei;
72 ei = alloc_inode_sb(sb, cache: efs_inode_cachep, GFP_KERNEL);
73 if (!ei)
74 return NULL;
75 return &ei->vfs_inode;
76}
77
78static void efs_free_inode(struct inode *inode)
79{
80 kmem_cache_free(s: efs_inode_cachep, objp: INODE_INFO(inode));
81}
82
83static 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
90static int __init init_inodecache(void)
91{
92 efs_inode_cachep = kmem_cache_create(name: "efs_inode_cache",
93 size: sizeof(struct efs_inode_info), align: 0,
94 SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
95 SLAB_ACCOUNT, ctor: init_once);
96 if (efs_inode_cachep == NULL)
97 return -ENOMEM;
98 return 0;
99}
100
101static 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(s: efs_inode_cachep);
109}
110
111static 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
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 .remount_fs = efs_remount,
123};
124
125static const struct export_operations efs_export_ops = {
126 .encode_fh = generic_encode_ino32_fh,
127 .fh_to_dentry = efs_fh_to_dentry,
128 .fh_to_parent = efs_fh_to_parent,
129 .get_parent = efs_get_parent,
130};
131
132static int __init init_efs_fs(void) {
133 int err;
134 pr_info(EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
135 err = init_inodecache();
136 if (err)
137 goto out1;
138 err = register_filesystem(&efs_fs_type);
139 if (err)
140 goto out;
141 return 0;
142out:
143 destroy_inodecache();
144out1:
145 return err;
146}
147
148static void __exit exit_efs_fs(void) {
149 unregister_filesystem(&efs_fs_type);
150 destroy_inodecache();
151}
152
153module_init(init_efs_fs)
154module_exit(exit_efs_fs)
155
156static efs_block_t efs_validate_vh(struct volume_header *vh) {
157 int i;
158 __be32 cs, *ui;
159 int csum;
160 efs_block_t sblock = 0; /* shuts up gcc */
161 struct pt_types *pt_entry;
162 int pt_type, slice = -1;
163
164 if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
165 /*
166 * assume that we're dealing with a partition and allow
167 * read_super() to try and detect a valid superblock
168 * on the next block.
169 */
170 return 0;
171 }
172
173 ui = ((__be32 *) (vh + 1)) - 1;
174 for(csum = 0; ui >= ((__be32 *) vh);) {
175 cs = *ui--;
176 csum += be32_to_cpu(cs);
177 }
178 if (csum) {
179 pr_warn("SGI disklabel: checksum bad, label corrupted\n");
180 return 0;
181 }
182
183#ifdef DEBUG
184 pr_debug("bf: \"%16s\"\n", vh->vh_bootfile);
185
186 for(i = 0; i < NVDIR; i++) {
187 int j;
188 char name[VDNAMESIZE+1];
189
190 for(j = 0; j < VDNAMESIZE; j++) {
191 name[j] = vh->vh_vd[i].vd_name[j];
192 }
193 name[j] = (char) 0;
194
195 if (name[0]) {
196 pr_debug("vh: %8s block: 0x%08x size: 0x%08x\n",
197 name, (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
198 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
199 }
200 }
201#endif
202
203 for(i = 0; i < NPARTAB; i++) {
204 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
205 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
206 if (pt_type == pt_entry->pt_type) break;
207 }
208#ifdef DEBUG
209 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
210 pr_debug("pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
211 i, (int)be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
212 (int)be32_to_cpu(vh->vh_pt[i].pt_nblks),
213 pt_type, (pt_entry->pt_name) ?
214 pt_entry->pt_name : "unknown");
215 }
216#endif
217 if (IS_EFS(pt_type)) {
218 sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
219 slice = i;
220 }
221 }
222
223 if (slice == -1) {
224 pr_notice("partition table contained no EFS partitions\n");
225#ifdef DEBUG
226 } else {
227 pr_info("using slice %d (type %s, offset 0x%x)\n", slice,
228 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
229 sblock);
230#endif
231 }
232 return sblock;
233}
234
235static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
236
237 if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
238 return -1;
239
240 sb->fs_magic = be32_to_cpu(super->fs_magic);
241 sb->total_blocks = be32_to_cpu(super->fs_size);
242 sb->first_block = be32_to_cpu(super->fs_firstcg);
243 sb->group_size = be32_to_cpu(super->fs_cgfsize);
244 sb->data_free = be32_to_cpu(super->fs_tfree);
245 sb->inode_free = be32_to_cpu(super->fs_tinode);
246 sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
247 sb->total_groups = be16_to_cpu(super->fs_ncg);
248
249 return 0;
250}
251
252static int efs_fill_super(struct super_block *s, void *d, int silent)
253{
254 struct efs_sb_info *sb;
255 struct buffer_head *bh;
256 struct inode *root;
257
258 sb = kzalloc(size: sizeof(struct efs_sb_info), GFP_KERNEL);
259 if (!sb)
260 return -ENOMEM;
261 s->s_fs_info = sb;
262 s->s_time_min = 0;
263 s->s_time_max = U32_MAX;
264
265 s->s_magic = EFS_SUPER_MAGIC;
266 if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
267 pr_err("device does not support %d byte blocks\n",
268 EFS_BLOCKSIZE);
269 return -EINVAL;
270 }
271
272 /* read the vh (volume header) block */
273 bh = sb_bread(sb: s, block: 0);
274
275 if (!bh) {
276 pr_err("cannot read volume header\n");
277 return -EIO;
278 }
279
280 /*
281 * if this returns zero then we didn't find any partition table.
282 * this isn't (yet) an error - just assume for the moment that
283 * the device is valid and go on to search for a superblock.
284 */
285 sb->fs_start = efs_validate_vh(vh: (struct volume_header *) bh->b_data);
286 brelse(bh);
287
288 if (sb->fs_start == -1) {
289 return -EINVAL;
290 }
291
292 bh = sb_bread(sb: s, block: sb->fs_start + EFS_SUPER);
293 if (!bh) {
294 pr_err("cannot read superblock\n");
295 return -EIO;
296 }
297
298 if (efs_validate_super(sb, super: (struct efs_super *) bh->b_data)) {
299#ifdef DEBUG
300 pr_warn("invalid superblock at block %u\n",
301 sb->fs_start + EFS_SUPER);
302#endif
303 brelse(bh);
304 return -EINVAL;
305 }
306 brelse(bh);
307
308 if (!sb_rdonly(sb: s)) {
309#ifdef DEBUG
310 pr_info("forcing read-only mode\n");
311#endif
312 s->s_flags |= SB_RDONLY;
313 }
314 s->s_op = &efs_superblock_operations;
315 s->s_export_op = &efs_export_ops;
316 root = efs_iget(s, EFS_ROOTINODE);
317 if (IS_ERR(ptr: root)) {
318 pr_err("get root inode failed\n");
319 return PTR_ERR(ptr: root);
320 }
321
322 s->s_root = d_make_root(root);
323 if (!(s->s_root)) {
324 pr_err("get root dentry failed\n");
325 return -ENOMEM;
326 }
327
328 return 0;
329}
330
331static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
332 struct super_block *sb = dentry->d_sb;
333 struct efs_sb_info *sbi = SUPER_INFO(sb);
334 u64 id = huge_encode_dev(dev: sb->s_bdev->bd_dev);
335
336 buf->f_type = EFS_SUPER_MAGIC; /* efs magic number */
337 buf->f_bsize = EFS_BLOCKSIZE; /* blocksize */
338 buf->f_blocks = sbi->total_groups * /* total data blocks */
339 (sbi->group_size - sbi->inode_blocks);
340 buf->f_bfree = sbi->data_free; /* free data blocks */
341 buf->f_bavail = sbi->data_free; /* free blocks for non-root */
342 buf->f_files = sbi->total_groups * /* total inodes */
343 sbi->inode_blocks *
344 (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
345 buf->f_ffree = sbi->inode_free; /* free inodes */
346 buf->f_fsid = u64_to_fsid(v: id);
347 buf->f_namelen = EFS_MAXNAMELEN; /* max filename length */
348
349 return 0;
350}
351
352

source code of linux/fs/efs/super.c