1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Optimized MPEG FS - inode and super operations.
4 * Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>
5 */
6 #include <linux/module.h>
7 #include <linux/sched.h>
8 #include <linux/slab.h>
9 #include <linux/fs.h>
10 #include <linux/vfs.h>
11 #include <linux/cred.h>
12 #include <linux/parser.h>
13 #include <linux/buffer_head.h>
14 #include <linux/vmalloc.h>
15 #include <linux/writeback.h>
16 #include <linux/seq_file.h>
17 #include <linux/crc-itu-t.h>
18 #include "omfs.h"
19
20 MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
21 MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
22 MODULE_LICENSE("GPL");
23
24 struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)
25 {
26 struct omfs_sb_info *sbi = OMFS_SB(sb);
27 if (block >= sbi->s_num_blocks)
28 return NULL;
29
30 return sb_bread(sb, clus_to_blk(sbi, block));
31 }
32
33 struct inode *omfs_new_inode(struct inode *dir, umode_t mode)
34 {
35 struct inode *inode;
36 u64 new_block;
37 int err;
38 int len;
39 struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
40
41 inode = new_inode(dir->i_sb);
42 if (!inode)
43 return ERR_PTR(-ENOMEM);
44
45 err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
46 &new_block, &len);
47 if (err)
48 goto fail;
49
50 inode->i_ino = new_block;
51 inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
52 inode->i_mapping->a_ops = &omfs_aops;
53
54 simple_inode_init_ts(inode);
55 switch (mode & S_IFMT) {
56 case S_IFDIR:
57 inode->i_op = &omfs_dir_inops;
58 inode->i_fop = &omfs_dir_operations;
59 inode->i_size = sbi->s_sys_blocksize;
60 inc_nlink(inode);
61 break;
62 case S_IFREG:
63 inode->i_op = &omfs_file_inops;
64 inode->i_fop = &omfs_file_operations;
65 inode->i_size = 0;
66 break;
67 }
68
69 insert_inode_hash(inode);
70 mark_inode_dirty(inode);
71 return inode;
72 fail:
73 make_bad_inode(inode);
74 iput(inode);
75 return ERR_PTR(err);
76 }
77
78 /*
79 * Update the header checksums for a dirty inode based on its contents.
80 * Caller is expected to hold the buffer head underlying oi and mark it
81 * dirty.
82 */
83 static void omfs_update_checksums(struct omfs_inode *oi)
84 {
85 int xor, i, ofs = 0, count;
86 u16 crc = 0;
87 unsigned char *ptr = (unsigned char *) oi;
88
89 count = be32_to_cpu(oi->i_head.h_body_size);
90 ofs = sizeof(struct omfs_header);
91
92 crc = crc_itu_t(crc, ptr + ofs, count);
93 oi->i_head.h_crc = cpu_to_be16(crc);
94
95 xor = ptr[0];
96 for (i = 1; i < OMFS_XOR_COUNT; i++)
97 xor ^= ptr[i];
98
99 oi->i_head.h_check_xor = xor;
100 }
101
102 static int __omfs_write_inode(struct inode *inode, int wait)
103 {
104 struct omfs_inode *oi;
105 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
106 struct buffer_head *bh, *bh2;
107 u64 ctime;
108 int i;
109 int ret = -EIO;
110 int sync_failed = 0;
111
112 /* get current inode since we may have written sibling ptrs etc. */
113 bh = omfs_bread(inode->i_sb, inode->i_ino);
114 if (!bh)
115 goto out;
116
117 oi = (struct omfs_inode *) bh->b_data;
118
119 oi->i_head.h_self = cpu_to_be64(inode->i_ino);
120 if (S_ISDIR(inode->i_mode))
121 oi->i_type = OMFS_DIR;
122 else if (S_ISREG(inode->i_mode))
123 oi->i_type = OMFS_FILE;
124 else {
125 printk(KERN_WARNING "omfs: unknown file type: %d\n",
126 inode->i_mode);
127 goto out_brelse;
128 }
129
130 oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
131 sizeof(struct omfs_header));
132 oi->i_head.h_version = 1;
133 oi->i_head.h_type = OMFS_INODE_NORMAL;
134 oi->i_head.h_magic = OMFS_IMAGIC;
135 oi->i_size = cpu_to_be64(inode->i_size);
136
137 ctime = inode_get_ctime_sec(inode) * 1000LL +
138 ((inode_get_ctime_nsec(inode) + 999)/1000);
139 oi->i_ctime = cpu_to_be64(ctime);
140
141 omfs_update_checksums(oi);
142
143 mark_buffer_dirty(bh);
144 if (wait) {
145 sync_dirty_buffer(bh);
146 if (buffer_req(bh) && !buffer_uptodate(bh))
147 sync_failed = 1;
148 }
149
150 /* if mirroring writes, copy to next fsblock */
151 for (i = 1; i < sbi->s_mirrors; i++) {
152 bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
153 if (!bh2)
154 goto out_brelse;
155
156 memcpy(bh2->b_data, bh->b_data, bh->b_size);
157 mark_buffer_dirty(bh2);
158 if (wait) {
159 sync_dirty_buffer(bh2);
160 if (buffer_req(bh2) && !buffer_uptodate(bh2))
161 sync_failed = 1;
162 }
163 brelse(bh2);
164 }
165 ret = (sync_failed) ? -EIO : 0;
166 out_brelse:
167 brelse(bh);
168 out:
169 return ret;
170 }
171
172 static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
173 {
174 return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
175 }
176
177 int omfs_sync_inode(struct inode *inode)
178 {
179 return __omfs_write_inode(inode, 1);
180 }
181
182 /*
183 * called when an entry is deleted, need to clear the bits in the
184 * bitmaps.
185 */
186 static void omfs_evict_inode(struct inode *inode)
187 {
188 truncate_inode_pages_final(&inode->i_data);
189 clear_inode(inode);
190
191 if (inode->i_nlink)
192 return;
193
194 if (S_ISREG(inode->i_mode)) {
195 inode->i_size = 0;
196 omfs_shrink_inode(inode);
197 }
198
199 omfs_clear_range(inode->i_sb, inode->i_ino, 2);
200 }
201
202 struct inode *omfs_iget(struct super_block *sb, ino_t ino)
203 {
204 struct omfs_sb_info *sbi = OMFS_SB(sb);
205 struct omfs_inode *oi;
206 struct buffer_head *bh;
207 u64 ctime;
208 unsigned long nsecs;
209 struct inode *inode;
210
211 inode = iget_locked(sb, ino);
212 if (!inode)
213 return ERR_PTR(-ENOMEM);
214 if (!(inode->i_state & I_NEW))
215 return inode;
216
217 bh = omfs_bread(inode->i_sb, ino);
218 if (!bh)
219 goto iget_failed;
220
221 oi = (struct omfs_inode *)bh->b_data;
222
223 /* check self */
224 if (ino != be64_to_cpu(oi->i_head.h_self))
225 goto fail_bh;
226
227 inode->i_uid = sbi->s_uid;
228 inode->i_gid = sbi->s_gid;
229
230 ctime = be64_to_cpu(oi->i_ctime);
231 nsecs = do_div(ctime, 1000) * 1000L;
232
233 inode_set_atime(inode, ctime, nsecs);
234 inode_set_mtime(inode, ctime, nsecs);
235 inode_set_ctime(inode, ctime, nsecs);
236
237 inode->i_mapping->a_ops = &omfs_aops;
238
239 switch (oi->i_type) {
240 case OMFS_DIR:
241 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
242 inode->i_op = &omfs_dir_inops;
243 inode->i_fop = &omfs_dir_operations;
244 inode->i_size = sbi->s_sys_blocksize;
245 inc_nlink(inode);
246 break;
247 case OMFS_FILE:
248 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
249 inode->i_fop = &omfs_file_operations;
250 inode->i_size = be64_to_cpu(oi->i_size);
251 break;
252 }
253 brelse(bh);
254 unlock_new_inode(inode);
255 return inode;
256 fail_bh:
257 brelse(bh);
258 iget_failed:
259 iget_failed(inode);
260 return ERR_PTR(-EIO);
261 }
262
263 static void omfs_put_super(struct super_block *sb)
264 {
265 struct omfs_sb_info *sbi = OMFS_SB(sb);
266 kfree(sbi->s_imap);
267 kfree(sbi);
268 sb->s_fs_info = NULL;
269 }
270
271 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
272 {
273 struct super_block *s = dentry->d_sb;
274 struct omfs_sb_info *sbi = OMFS_SB(s);
275 u64 id = huge_encode_dev(s->s_bdev->bd_dev);
276
277 buf->f_type = OMFS_MAGIC;
278 buf->f_bsize = sbi->s_blocksize;
279 buf->f_blocks = sbi->s_num_blocks;
280 buf->f_files = sbi->s_num_blocks;
281 buf->f_namelen = OMFS_NAMELEN;
282 buf->f_fsid = u64_to_fsid(id);
283
284 buf->f_bfree = buf->f_bavail = buf->f_ffree =
285 omfs_count_free(s);
286
287 return 0;
288 }
289
290 /*
291 * Display the mount options in /proc/mounts.
292 */
293 static int omfs_show_options(struct seq_file *m, struct dentry *root)
294 {
295 struct omfs_sb_info *sbi = OMFS_SB(root->d_sb);
296 umode_t cur_umask = current_umask();
297
298 if (!uid_eq(sbi->s_uid, current_uid()))
299 seq_printf(m, ",uid=%u",
300 from_kuid_munged(&init_user_ns, sbi->s_uid));
301 if (!gid_eq(sbi->s_gid, current_gid()))
302 seq_printf(m, ",gid=%u",
303 from_kgid_munged(&init_user_ns, sbi->s_gid));
304
305 if (sbi->s_dmask == sbi->s_fmask) {
306 if (sbi->s_fmask != cur_umask)
307 seq_printf(m, ",umask=%o", sbi->s_fmask);
308 } else {
309 if (sbi->s_dmask != cur_umask)
310 seq_printf(m, ",dmask=%o", sbi->s_dmask);
311 if (sbi->s_fmask != cur_umask)
312 seq_printf(m, ",fmask=%o", sbi->s_fmask);
313 }
314
315 return 0;
316 }
317
318 static const struct super_operations omfs_sops = {
319 .write_inode = omfs_write_inode,
320 .evict_inode = omfs_evict_inode,
321 .put_super = omfs_put_super,
322 .statfs = omfs_statfs,
323 .show_options = omfs_show_options,
324 };
325
326 /*
327 * For Rio Karma, there is an on-disk free bitmap whose location is
328 * stored in the root block. For ReplayTV, there is no such free bitmap
329 * so we have to walk the tree. Both inodes and file data are allocated
330 * from the same map. This array can be big (300k) so we allocate
331 * in units of the blocksize.
332 */
333 static int omfs_get_imap(struct super_block *sb)
334 {
335 unsigned int bitmap_size, array_size;
336 int count;
337 struct omfs_sb_info *sbi = OMFS_SB(sb);
338 struct buffer_head *bh;
339 unsigned long **ptr;
340 sector_t block;
341
342 bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
343 array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
344
345 if (sbi->s_bitmap_ino == ~0ULL)
346 goto out;
347
348 sbi->s_imap_size = array_size;
349 sbi->s_imap = kcalloc(array_size, sizeof(unsigned long *), GFP_KERNEL);
350 if (!sbi->s_imap)
351 goto nomem;
352
353 block = clus_to_blk(sbi, sbi->s_bitmap_ino);
354 if (block >= sbi->s_num_blocks)
355 goto nomem;
356
357 ptr = sbi->s_imap;
358 for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
359 bh = sb_bread(sb, block++);
360 if (!bh)
361 goto nomem_free;
362 *ptr = kmemdup(bh->b_data, sb->s_blocksize, GFP_KERNEL);
363 if (!*ptr) {
364 brelse(bh);
365 goto nomem_free;
366 }
367 if (count < sb->s_blocksize)
368 memset((void *)*ptr + count, 0xff,
369 sb->s_blocksize - count);
370 brelse(bh);
371 ptr++;
372 }
373 out:
374 return 0;
375
376 nomem_free:
377 for (count = 0; count < array_size; count++)
378 kfree(sbi->s_imap[count]);
379
380 kfree(sbi->s_imap);
381 nomem:
382 sbi->s_imap = NULL;
383 sbi->s_imap_size = 0;
384 return -ENOMEM;
385 }
386
387 enum {
388 Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask, Opt_err
389 };
390
391 static const match_table_t tokens = {
392 {Opt_uid, "uid=%u"},
393 {Opt_gid, "gid=%u"},
394 {Opt_umask, "umask=%o"},
395 {Opt_dmask, "dmask=%o"},
396 {Opt_fmask, "fmask=%o"},
397 {Opt_err, NULL},
398 };
399
400 static int parse_options(char *options, struct omfs_sb_info *sbi)
401 {
402 char *p;
403 substring_t args[MAX_OPT_ARGS];
404 int option;
405
406 if (!options)
407 return 1;
408
409 while ((p = strsep(&options, ",")) != NULL) {
410 int token;
411 if (!*p)
412 continue;
413
414 token = match_token(p, tokens, args);
415 switch (token) {
416 case Opt_uid:
417 if (match_int(&args[0], &option))
418 return 0;
419 sbi->s_uid = make_kuid(current_user_ns(), option);
420 if (!uid_valid(sbi->s_uid))
421 return 0;
422 break;
423 case Opt_gid:
424 if (match_int(&args[0], &option))
425 return 0;
426 sbi->s_gid = make_kgid(current_user_ns(), option);
427 if (!gid_valid(sbi->s_gid))
428 return 0;
429 break;
430 case Opt_umask:
431 if (match_octal(&args[0], &option))
432 return 0;
433 sbi->s_fmask = sbi->s_dmask = option;
434 break;
435 case Opt_dmask:
436 if (match_octal(&args[0], &option))
437 return 0;
438 sbi->s_dmask = option;
439 break;
440 case Opt_fmask:
441 if (match_octal(&args[0], &option))
442 return 0;
443 sbi->s_fmask = option;
444 break;
445 default:
446 return 0;
447 }
448 }
449 return 1;
450 }
451
452 static int omfs_fill_super(struct super_block *sb, void *data, int silent)
453 {
454 struct buffer_head *bh, *bh2;
455 struct omfs_super_block *omfs_sb;
456 struct omfs_root_block *omfs_rb;
457 struct omfs_sb_info *sbi;
458 struct inode *root;
459 int ret = -EINVAL;
460
461 sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
462 if (!sbi)
463 return -ENOMEM;
464
465 sb->s_fs_info = sbi;
466
467 sbi->s_uid = current_uid();
468 sbi->s_gid = current_gid();
469 sbi->s_dmask = sbi->s_fmask = current_umask();
470
471 if (!parse_options((char *) data, sbi))
472 goto end;
473
474 sb->s_maxbytes = 0xffffffff;
475
476 sb->s_time_gran = NSEC_PER_MSEC;
477 sb->s_time_min = 0;
478 sb->s_time_max = U64_MAX / MSEC_PER_SEC;
479
480 sb_set_blocksize(sb, 0x200);
481
482 bh = sb_bread(sb, 0);
483 if (!bh)
484 goto end;
485
486 omfs_sb = (struct omfs_super_block *)bh->b_data;
487
488 if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
489 if (!silent)
490 printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
491 omfs_sb->s_magic);
492 goto out_brelse_bh;
493 }
494 sb->s_magic = OMFS_MAGIC;
495
496 sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
497 sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
498 sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
499 sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
500 sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
501 mutex_init(&sbi->s_bitmap_lock);
502
503 if (sbi->s_num_blocks > OMFS_MAX_BLOCKS) {
504 printk(KERN_ERR "omfs: sysblock number (%llx) is out of range\n",
505 (unsigned long long)sbi->s_num_blocks);
506 goto out_brelse_bh;
507 }
508
509 if (sbi->s_sys_blocksize > PAGE_SIZE) {
510 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
511 sbi->s_sys_blocksize);
512 goto out_brelse_bh;
513 }
514
515 if (sbi->s_blocksize < sbi->s_sys_blocksize ||
516 sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
517 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
518 sbi->s_blocksize);
519 goto out_brelse_bh;
520 }
521
522 /*
523 * Use sys_blocksize as the fs block since it is smaller than a
524 * page while the fs blocksize can be larger.
525 */
526 sb_set_blocksize(sb, sbi->s_sys_blocksize);
527
528 /*
529 * ...and the difference goes into a shift. sys_blocksize is always
530 * a power of two factor of blocksize.
531 */
532 sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
533 get_bitmask_order(sbi->s_sys_blocksize);
534
535 bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
536 if (!bh2)
537 goto out_brelse_bh;
538
539 omfs_rb = (struct omfs_root_block *)bh2->b_data;
540
541 sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
542 sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
543
544 if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
545 printk(KERN_ERR "omfs: block count discrepancy between "
546 "super and root blocks (%llx, %llx)\n",
547 (unsigned long long)sbi->s_num_blocks,
548 (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
549 goto out_brelse_bh2;
550 }
551
552 if (sbi->s_bitmap_ino != ~0ULL &&
553 sbi->s_bitmap_ino > sbi->s_num_blocks) {
554 printk(KERN_ERR "omfs: free space bitmap location is corrupt "
555 "(%llx, total blocks %llx)\n",
556 (unsigned long long) sbi->s_bitmap_ino,
557 (unsigned long long) sbi->s_num_blocks);
558 goto out_brelse_bh2;
559 }
560 if (sbi->s_clustersize < 1 ||
561 sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
562 printk(KERN_ERR "omfs: cluster size out of range (%d)",
563 sbi->s_clustersize);
564 goto out_brelse_bh2;
565 }
566
567 ret = omfs_get_imap(sb);
568 if (ret)
569 goto out_brelse_bh2;
570
571 sb->s_op = &omfs_sops;
572
573 root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
574 if (IS_ERR(root)) {
575 ret = PTR_ERR(root);
576 goto out_brelse_bh2;
577 }
578
579 sb->s_root = d_make_root(root);
580 if (!sb->s_root) {
581 ret = -ENOMEM;
582 goto out_brelse_bh2;
583 }
584 printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
585
586 ret = 0;
587 out_brelse_bh2:
588 brelse(bh2);
589 out_brelse_bh:
590 brelse(bh);
591 end:
592 if (ret)
593 kfree(sbi);
594 return ret;
595 }
596
597 static struct dentry *omfs_mount(struct file_system_type *fs_type,
598 int flags, const char *dev_name, void *data)
599 {
600 return mount_bdev(fs_type, flags, dev_name, data, omfs_fill_super);
601 }
602
603 static struct file_system_type omfs_fs_type = {
604 .owner = THIS_MODULE,
605 .name = "omfs",
606 .mount = omfs_mount,
607 .kill_sb = kill_block_super,
608 .fs_flags = FS_REQUIRES_DEV,
609 };
610 MODULE_ALIAS_FS("omfs");
611
612 static int __init init_omfs_fs(void)
613 {
614 return register_filesystem(&omfs_fs_type);
615 }
616
617 static void __exit exit_omfs_fs(void)
618 {
619 unregister_filesystem(&omfs_fs_type);
620 }
621
622 module_init(init_omfs_fs);
623 module_exit(exit_omfs_fs);
624
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