1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * fs/bfs/inode.c
4 * BFS superblock and inode operations.
5 * Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
6 * From fs/minix, Copyright (C) 1991, 1992 Linus Torvalds.
7 * Made endianness-clean by Andrew Stribblehill <ads@wompom.org>, 2005.
8 */
9
10 #include <linux/module.h>
11 #include <linux/mm.h>
12 #include <linux/slab.h>
13 #include <linux/init.h>
14 #include <linux/fs.h>
15 #include <linux/buffer_head.h>
16 #include <linux/vfs.h>
17 #include <linux/writeback.h>
18 #include <linux/uio.h>
19 #include <linux/uaccess.h>
20 #include <linux/fs_context.h>
21 #include "bfs.h"
22
23 MODULE_AUTHOR("Tigran Aivazian <aivazian.tigran@gmail.com>");
24 MODULE_DESCRIPTION("SCO UnixWare BFS filesystem for Linux");
25 MODULE_LICENSE("GPL");
26
27 #undef DEBUG
28
29 #ifdef DEBUG
30 #define dprintf(x...) printf(x)
31 #else
32 #define dprintf(x...)
33 #endif
34
bfs_iget(struct super_block * sb,unsigned long ino)35 struct inode *bfs_iget(struct super_block *sb, unsigned long ino)
36 {
37 struct bfs_inode *di;
38 struct inode *inode;
39 struct buffer_head *bh;
40 int block, off;
41
42 inode = iget_locked(sb, ino);
43 if (!inode)
44 return ERR_PTR(-ENOMEM);
45 if (!(inode->i_state & I_NEW))
46 return inode;
47
48 if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
49 printf("Bad inode number %s:%08lx\n", inode->i_sb->s_id, ino);
50 goto error;
51 }
52
53 block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
54 bh = sb_bread(inode->i_sb, block);
55 if (!bh) {
56 printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id,
57 ino);
58 goto error;
59 }
60
61 off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
62 di = (struct bfs_inode *)bh->b_data + off;
63
64 /*
65 * https://martin.hinner.info/fs/bfs/bfs-structure.html explains that
66 * BFS in SCO UnixWare environment used only lower 9 bits of di->i_mode
67 * value. This means that, although bfs_write_inode() saves whole
68 * inode->i_mode bits (which include S_IFMT bits and S_IS{UID,GID,VTX}
69 * bits), middle 7 bits of di->i_mode value can be garbage when these
70 * bits were not saved by bfs_write_inode().
71 * Since we can't tell whether middle 7 bits are garbage, use only
72 * lower 12 bits (i.e. tolerate S_IS{UID,GID,VTX} bits possibly being
73 * garbage) and reconstruct S_IFMT bits for Linux environment from
74 * di->i_vtype value.
75 */
76 inode->i_mode = 0x00000FFF & le32_to_cpu(di->i_mode);
77 if (le32_to_cpu(di->i_vtype) == BFS_VDIR) {
78 inode->i_mode |= S_IFDIR;
79 inode->i_op = &bfs_dir_inops;
80 inode->i_fop = &bfs_dir_operations;
81 } else if (le32_to_cpu(di->i_vtype) == BFS_VREG) {
82 inode->i_mode |= S_IFREG;
83 inode->i_op = &bfs_file_inops;
84 inode->i_fop = &bfs_file_operations;
85 inode->i_mapping->a_ops = &bfs_aops;
86 } else {
87 brelse(bh);
88 printf("Unknown vtype=%u %s:%08lx\n",
89 le32_to_cpu(di->i_vtype), inode->i_sb->s_id, ino);
90 goto error;
91 }
92
93 BFS_I(inode)->i_sblock = le32_to_cpu(di->i_sblock);
94 BFS_I(inode)->i_eblock = le32_to_cpu(di->i_eblock);
95 BFS_I(inode)->i_dsk_ino = le16_to_cpu(di->i_ino);
96 i_uid_write(inode, le32_to_cpu(di->i_uid));
97 i_gid_write(inode, le32_to_cpu(di->i_gid));
98 set_nlink(inode, le32_to_cpu(di->i_nlink));
99 inode->i_size = BFS_FILESIZE(di);
100 inode->i_blocks = BFS_FILEBLOCKS(di);
101 inode_set_atime(inode, le32_to_cpu(di->i_atime), 0);
102 inode_set_mtime(inode, le32_to_cpu(di->i_mtime), 0);
103 inode_set_ctime(inode, le32_to_cpu(di->i_ctime), 0);
104
105 brelse(bh);
106 unlock_new_inode(inode);
107 return inode;
108
109 error:
110 iget_failed(inode);
111 return ERR_PTR(-EIO);
112 }
113
find_inode(struct super_block * sb,u16 ino,struct buffer_head ** p)114 static struct bfs_inode *find_inode(struct super_block *sb, u16 ino, struct buffer_head **p)
115 {
116 if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(sb)->si_lasti)) {
117 printf("Bad inode number %s:%08x\n", sb->s_id, ino);
118 return ERR_PTR(-EIO);
119 }
120
121 ino -= BFS_ROOT_INO;
122
123 *p = sb_bread(sb, 1 + ino / BFS_INODES_PER_BLOCK);
124 if (!*p) {
125 printf("Unable to read inode %s:%08x\n", sb->s_id, ino);
126 return ERR_PTR(-EIO);
127 }
128
129 return (struct bfs_inode *)(*p)->b_data + ino % BFS_INODES_PER_BLOCK;
130 }
131
bfs_write_inode(struct inode * inode,struct writeback_control * wbc)132 static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
133 {
134 struct bfs_sb_info *info = BFS_SB(inode->i_sb);
135 unsigned int ino = (u16)inode->i_ino;
136 unsigned long i_sblock;
137 struct bfs_inode *di;
138 struct buffer_head *bh;
139 int err = 0;
140
141 dprintf("ino=%08x\n", ino);
142
143 di = find_inode(inode->i_sb, ino, &bh);
144 if (IS_ERR(di))
145 return PTR_ERR(di);
146
147 mutex_lock(&info->bfs_lock);
148
149 if (ino == BFS_ROOT_INO)
150 di->i_vtype = cpu_to_le32(BFS_VDIR);
151 else
152 di->i_vtype = cpu_to_le32(BFS_VREG);
153
154 di->i_ino = cpu_to_le16(ino);
155 di->i_mode = cpu_to_le32(inode->i_mode);
156 di->i_uid = cpu_to_le32(i_uid_read(inode));
157 di->i_gid = cpu_to_le32(i_gid_read(inode));
158 di->i_nlink = cpu_to_le32(inode->i_nlink);
159 di->i_atime = cpu_to_le32(inode_get_atime_sec(inode));
160 di->i_mtime = cpu_to_le32(inode_get_mtime_sec(inode));
161 di->i_ctime = cpu_to_le32(inode_get_ctime_sec(inode));
162 i_sblock = BFS_I(inode)->i_sblock;
163 di->i_sblock = cpu_to_le32(i_sblock);
164 di->i_eblock = cpu_to_le32(BFS_I(inode)->i_eblock);
165 di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1);
166
167 mark_buffer_dirty(bh);
168 if (wbc->sync_mode == WB_SYNC_ALL) {
169 sync_dirty_buffer(bh);
170 if (buffer_req(bh) && !buffer_uptodate(bh))
171 err = -EIO;
172 }
173 brelse(bh);
174 mutex_unlock(&info->bfs_lock);
175 return err;
176 }
177
bfs_evict_inode(struct inode * inode)178 static void bfs_evict_inode(struct inode *inode)
179 {
180 unsigned long ino = inode->i_ino;
181 struct bfs_inode *di;
182 struct buffer_head *bh;
183 struct super_block *s = inode->i_sb;
184 struct bfs_sb_info *info = BFS_SB(s);
185 struct bfs_inode_info *bi = BFS_I(inode);
186
187 dprintf("ino=%08lx\n", ino);
188
189 truncate_inode_pages_final(&inode->i_data);
190 invalidate_inode_buffers(inode);
191 clear_inode(inode);
192
193 if (inode->i_nlink)
194 return;
195
196 di = find_inode(s, inode->i_ino, &bh);
197 if (IS_ERR(di))
198 return;
199
200 mutex_lock(&info->bfs_lock);
201 /* clear on-disk inode */
202 memset(di, 0, sizeof(struct bfs_inode));
203 mark_buffer_dirty(bh);
204 brelse(bh);
205
206 if (bi->i_dsk_ino) {
207 if (bi->i_sblock)
208 info->si_freeb += bi->i_eblock + 1 - bi->i_sblock;
209 info->si_freei++;
210 clear_bit(ino, info->si_imap);
211 bfs_dump_imap("evict_inode", s);
212 }
213
214 /*
215 * If this was the last file, make the previous block
216 * "last block of the last file" even if there is no
217 * real file there, saves us 1 gap.
218 */
219 if (info->si_lf_eblk == bi->i_eblock)
220 info->si_lf_eblk = bi->i_sblock - 1;
221 mutex_unlock(&info->bfs_lock);
222 }
223
bfs_put_super(struct super_block * s)224 static void bfs_put_super(struct super_block *s)
225 {
226 struct bfs_sb_info *info = BFS_SB(s);
227
228 if (!info)
229 return;
230
231 mutex_destroy(&info->bfs_lock);
232 kfree(info);
233 s->s_fs_info = NULL;
234 }
235
bfs_statfs(struct dentry * dentry,struct kstatfs * buf)236 static int bfs_statfs(struct dentry *dentry, struct kstatfs *buf)
237 {
238 struct super_block *s = dentry->d_sb;
239 struct bfs_sb_info *info = BFS_SB(s);
240 u64 id = huge_encode_dev(s->s_bdev->bd_dev);
241 buf->f_type = BFS_MAGIC;
242 buf->f_bsize = s->s_blocksize;
243 buf->f_blocks = info->si_blocks;
244 buf->f_bfree = buf->f_bavail = info->si_freeb;
245 buf->f_files = info->si_lasti + 1 - BFS_ROOT_INO;
246 buf->f_ffree = info->si_freei;
247 buf->f_fsid = u64_to_fsid(id);
248 buf->f_namelen = BFS_NAMELEN;
249 return 0;
250 }
251
252 static struct kmem_cache *bfs_inode_cachep;
253
bfs_alloc_inode(struct super_block * sb)254 static struct inode *bfs_alloc_inode(struct super_block *sb)
255 {
256 struct bfs_inode_info *bi;
257 bi = alloc_inode_sb(sb, bfs_inode_cachep, GFP_KERNEL);
258 if (!bi)
259 return NULL;
260 return &bi->vfs_inode;
261 }
262
bfs_free_inode(struct inode * inode)263 static void bfs_free_inode(struct inode *inode)
264 {
265 kmem_cache_free(bfs_inode_cachep, BFS_I(inode));
266 }
267
init_once(void * foo)268 static void init_once(void *foo)
269 {
270 struct bfs_inode_info *bi = foo;
271
272 inode_init_once(&bi->vfs_inode);
273 }
274
init_inodecache(void)275 static int __init init_inodecache(void)
276 {
277 bfs_inode_cachep = kmem_cache_create("bfs_inode_cache",
278 sizeof(struct bfs_inode_info),
279 0, (SLAB_RECLAIM_ACCOUNT|
280 SLAB_ACCOUNT),
281 init_once);
282 if (bfs_inode_cachep == NULL)
283 return -ENOMEM;
284 return 0;
285 }
286
destroy_inodecache(void)287 static void destroy_inodecache(void)
288 {
289 /*
290 * Make sure all delayed rcu free inodes are flushed before we
291 * destroy cache.
292 */
293 rcu_barrier();
294 kmem_cache_destroy(bfs_inode_cachep);
295 }
296
297 static const struct super_operations bfs_sops = {
298 .alloc_inode = bfs_alloc_inode,
299 .free_inode = bfs_free_inode,
300 .write_inode = bfs_write_inode,
301 .evict_inode = bfs_evict_inode,
302 .put_super = bfs_put_super,
303 .statfs = bfs_statfs,
304 };
305
bfs_dump_imap(const char * prefix,struct super_block * s)306 void bfs_dump_imap(const char *prefix, struct super_block *s)
307 {
308 #ifdef DEBUG
309 int i;
310 char *tmpbuf = (char *)get_zeroed_page(GFP_KERNEL);
311
312 if (!tmpbuf)
313 return;
314 for (i = BFS_SB(s)->si_lasti; i >= 0; i--) {
315 if (i > PAGE_SIZE - 100) break;
316 if (test_bit(i, BFS_SB(s)->si_imap))
317 strcat(tmpbuf, "1");
318 else
319 strcat(tmpbuf, "0");
320 }
321 printf("%s: lasti=%08lx <%s>\n", prefix, BFS_SB(s)->si_lasti, tmpbuf);
322 free_page((unsigned long)tmpbuf);
323 #endif
324 }
325
bfs_fill_super(struct super_block * s,struct fs_context * fc)326 static int bfs_fill_super(struct super_block *s, struct fs_context *fc)
327 {
328 struct buffer_head *bh, *sbh;
329 struct bfs_super_block *bfs_sb;
330 struct inode *inode;
331 unsigned i;
332 struct bfs_sb_info *info;
333 int ret = -EINVAL;
334 unsigned long i_sblock, i_eblock, i_eoff, s_size;
335 int silent = fc->sb_flags & SB_SILENT;
336
337 info = kzalloc(sizeof(*info), GFP_KERNEL);
338 if (!info)
339 return -ENOMEM;
340 mutex_init(&info->bfs_lock);
341 s->s_fs_info = info;
342 s->s_time_min = 0;
343 s->s_time_max = U32_MAX;
344
345 sb_set_blocksize(s, BFS_BSIZE);
346
347 sbh = sb_bread(s, 0);
348 if (!sbh)
349 goto out;
350 bfs_sb = (struct bfs_super_block *)sbh->b_data;
351 if (le32_to_cpu(bfs_sb->s_magic) != BFS_MAGIC) {
352 if (!silent)
353 printf("No BFS filesystem on %s (magic=%08x)\n", s->s_id, le32_to_cpu(bfs_sb->s_magic));
354 goto out1;
355 }
356 if (BFS_UNCLEAN(bfs_sb, s) && !silent)
357 printf("%s is unclean, continuing\n", s->s_id);
358
359 s->s_magic = BFS_MAGIC;
360
361 if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end) ||
362 le32_to_cpu(bfs_sb->s_start) < sizeof(struct bfs_super_block) + sizeof(struct bfs_dirent)) {
363 printf("Superblock is corrupted on %s\n", s->s_id);
364 goto out1;
365 }
366
367 info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) / sizeof(struct bfs_inode) + BFS_ROOT_INO - 1;
368 if (info->si_lasti == BFS_MAX_LASTI)
369 printf("NOTE: filesystem %s was created with 512 inodes, the real maximum is 511, mounting anyway\n", s->s_id);
370 else if (info->si_lasti > BFS_MAX_LASTI) {
371 printf("Impossible last inode number %lu > %d on %s\n", info->si_lasti, BFS_MAX_LASTI, s->s_id);
372 goto out1;
373 }
374 for (i = 0; i < BFS_ROOT_INO; i++)
375 set_bit(i, info->si_imap);
376
377 s->s_op = &bfs_sops;
378 inode = bfs_iget(s, BFS_ROOT_INO);
379 if (IS_ERR(inode)) {
380 ret = PTR_ERR(inode);
381 goto out1;
382 }
383 s->s_root = d_make_root(inode);
384 if (!s->s_root) {
385 ret = -ENOMEM;
386 goto out1;
387 }
388
389 info->si_blocks = (le32_to_cpu(bfs_sb->s_end) + 1) >> BFS_BSIZE_BITS;
390 info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1 - le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS;
391 info->si_freei = 0;
392 info->si_lf_eblk = 0;
393
394 /* can we read the last block? */
395 bh = sb_bread(s, info->si_blocks - 1);
396 if (!bh) {
397 printf("Last block not available on %s: %lu\n", s->s_id, info->si_blocks - 1);
398 ret = -EIO;
399 goto out2;
400 }
401 brelse(bh);
402
403 bh = NULL;
404 for (i = BFS_ROOT_INO; i <= info->si_lasti; i++) {
405 struct bfs_inode *di;
406 int block = (i - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
407 int off = (i - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
408 unsigned long eblock;
409
410 if (!off) {
411 brelse(bh);
412 bh = sb_bread(s, block);
413 }
414
415 if (!bh)
416 continue;
417
418 di = (struct bfs_inode *)bh->b_data + off;
419
420 /* test if filesystem is not corrupted */
421
422 i_eoff = le32_to_cpu(di->i_eoffset);
423 i_sblock = le32_to_cpu(di->i_sblock);
424 i_eblock = le32_to_cpu(di->i_eblock);
425 s_size = le32_to_cpu(bfs_sb->s_end);
426
427 if (i_sblock > info->si_blocks ||
428 i_eblock > info->si_blocks ||
429 i_sblock > i_eblock ||
430 (i_eoff != le32_to_cpu(-1) && i_eoff > s_size) ||
431 i_sblock * BFS_BSIZE > i_eoff) {
432
433 printf("Inode 0x%08x corrupted on %s\n", i, s->s_id);
434
435 brelse(bh);
436 ret = -EIO;
437 goto out2;
438 }
439
440 if (!di->i_ino) {
441 info->si_freei++;
442 continue;
443 }
444 set_bit(i, info->si_imap);
445 info->si_freeb -= BFS_FILEBLOCKS(di);
446
447 eblock = le32_to_cpu(di->i_eblock);
448 if (eblock > info->si_lf_eblk)
449 info->si_lf_eblk = eblock;
450 }
451 brelse(bh);
452 brelse(sbh);
453 bfs_dump_imap("fill_super", s);
454 return 0;
455
456 out2:
457 dput(s->s_root);
458 s->s_root = NULL;
459 out1:
460 brelse(sbh);
461 out:
462 mutex_destroy(&info->bfs_lock);
463 kfree(info);
464 s->s_fs_info = NULL;
465 return ret;
466 }
467
bfs_get_tree(struct fs_context * fc)468 static int bfs_get_tree(struct fs_context *fc)
469 {
470 return get_tree_bdev(fc, bfs_fill_super);
471 }
472
473 static const struct fs_context_operations bfs_context_ops = {
474 .get_tree = bfs_get_tree,
475 };
476
bfs_init_fs_context(struct fs_context * fc)477 static int bfs_init_fs_context(struct fs_context *fc)
478 {
479 fc->ops = &bfs_context_ops;
480
481 return 0;
482 }
483
484 static struct file_system_type bfs_fs_type = {
485 .owner = THIS_MODULE,
486 .name = "bfs",
487 .init_fs_context = bfs_init_fs_context,
488 .kill_sb = kill_block_super,
489 .fs_flags = FS_REQUIRES_DEV,
490 };
491 MODULE_ALIAS_FS("bfs");
492
init_bfs_fs(void)493 static int __init init_bfs_fs(void)
494 {
495 int err = init_inodecache();
496 if (err)
497 goto out1;
498 err = register_filesystem(&bfs_fs_type);
499 if (err)
500 goto out;
501 return 0;
502 out:
503 destroy_inodecache();
504 out1:
505 return err;
506 }
507
exit_bfs_fs(void)508 static void __exit exit_bfs_fs(void)
509 {
510 unregister_filesystem(&bfs_fs_type);
511 destroy_inodecache();
512 }
513
514 module_init(init_bfs_fs)
515 module_exit(exit_bfs_fs)
516