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
omfs_bread(struct super_block * sb,sector_t block)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
omfs_new_inode(struct inode * dir,umode_t mode)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 inode->i_atime = inode->i_mtime = inode_set_ctime_current(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 */
omfs_update_checksums(struct omfs_inode * oi)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
__omfs_write_inode(struct inode * inode,int wait)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(inode).tv_sec * 1000LL +
138 ((inode_get_ctime(inode).tv_nsec + 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
omfs_write_inode(struct inode * inode,struct writeback_control * wbc)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
omfs_sync_inode(struct inode * inode)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 */
omfs_evict_inode(struct inode * inode)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
omfs_iget(struct super_block * sb,ino_t ino)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->i_atime.tv_sec = ctime;
234 inode->i_mtime.tv_sec = ctime;
235 inode_set_ctime(inode, ctime, nsecs);
236 inode->i_atime.tv_nsec = nsecs;
237 inode->i_mtime.tv_nsec = nsecs;
238
239 inode->i_mapping->a_ops = &omfs_aops;
240
241 switch (oi->i_type) {
242 case OMFS_DIR:
243 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
244 inode->i_op = &omfs_dir_inops;
245 inode->i_fop = &omfs_dir_operations;
246 inode->i_size = sbi->s_sys_blocksize;
247 inc_nlink(inode);
248 break;
249 case OMFS_FILE:
250 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
251 inode->i_fop = &omfs_file_operations;
252 inode->i_size = be64_to_cpu(oi->i_size);
253 break;
254 }
255 brelse(bh);
256 unlock_new_inode(inode);
257 return inode;
258 fail_bh:
259 brelse(bh);
260 iget_failed:
261 iget_failed(inode);
262 return ERR_PTR(-EIO);
263 }
264
omfs_put_super(struct super_block * sb)265 static void omfs_put_super(struct super_block *sb)
266 {
267 struct omfs_sb_info *sbi = OMFS_SB(sb);
268 kfree(sbi->s_imap);
269 kfree(sbi);
270 sb->s_fs_info = NULL;
271 }
272
omfs_statfs(struct dentry * dentry,struct kstatfs * buf)273 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
274 {
275 struct super_block *s = dentry->d_sb;
276 struct omfs_sb_info *sbi = OMFS_SB(s);
277 u64 id = huge_encode_dev(s->s_bdev->bd_dev);
278
279 buf->f_type = OMFS_MAGIC;
280 buf->f_bsize = sbi->s_blocksize;
281 buf->f_blocks = sbi->s_num_blocks;
282 buf->f_files = sbi->s_num_blocks;
283 buf->f_namelen = OMFS_NAMELEN;
284 buf->f_fsid = u64_to_fsid(id);
285
286 buf->f_bfree = buf->f_bavail = buf->f_ffree =
287 omfs_count_free(s);
288
289 return 0;
290 }
291
292 /*
293 * Display the mount options in /proc/mounts.
294 */
omfs_show_options(struct seq_file * m,struct dentry * root)295 static int omfs_show_options(struct seq_file *m, struct dentry *root)
296 {
297 struct omfs_sb_info *sbi = OMFS_SB(root->d_sb);
298 umode_t cur_umask = current_umask();
299
300 if (!uid_eq(sbi->s_uid, current_uid()))
301 seq_printf(m, ",uid=%u",
302 from_kuid_munged(&init_user_ns, sbi->s_uid));
303 if (!gid_eq(sbi->s_gid, current_gid()))
304 seq_printf(m, ",gid=%u",
305 from_kgid_munged(&init_user_ns, sbi->s_gid));
306
307 if (sbi->s_dmask == sbi->s_fmask) {
308 if (sbi->s_fmask != cur_umask)
309 seq_printf(m, ",umask=%o", sbi->s_fmask);
310 } else {
311 if (sbi->s_dmask != cur_umask)
312 seq_printf(m, ",dmask=%o", sbi->s_dmask);
313 if (sbi->s_fmask != cur_umask)
314 seq_printf(m, ",fmask=%o", sbi->s_fmask);
315 }
316
317 return 0;
318 }
319
320 static const struct super_operations omfs_sops = {
321 .write_inode = omfs_write_inode,
322 .evict_inode = omfs_evict_inode,
323 .put_super = omfs_put_super,
324 .statfs = omfs_statfs,
325 .show_options = omfs_show_options,
326 };
327
328 /*
329 * For Rio Karma, there is an on-disk free bitmap whose location is
330 * stored in the root block. For ReplayTV, there is no such free bitmap
331 * so we have to walk the tree. Both inodes and file data are allocated
332 * from the same map. This array can be big (300k) so we allocate
333 * in units of the blocksize.
334 */
omfs_get_imap(struct super_block * sb)335 static int omfs_get_imap(struct super_block *sb)
336 {
337 unsigned int bitmap_size, array_size;
338 int count;
339 struct omfs_sb_info *sbi = OMFS_SB(sb);
340 struct buffer_head *bh;
341 unsigned long **ptr;
342 sector_t block;
343
344 bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
345 array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
346
347 if (sbi->s_bitmap_ino == ~0ULL)
348 goto out;
349
350 sbi->s_imap_size = array_size;
351 sbi->s_imap = kcalloc(array_size, sizeof(unsigned long *), GFP_KERNEL);
352 if (!sbi->s_imap)
353 goto nomem;
354
355 block = clus_to_blk(sbi, sbi->s_bitmap_ino);
356 if (block >= sbi->s_num_blocks)
357 goto nomem;
358
359 ptr = sbi->s_imap;
360 for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
361 bh = sb_bread(sb, block++);
362 if (!bh)
363 goto nomem_free;
364 *ptr = kmemdup(bh->b_data, sb->s_blocksize, GFP_KERNEL);
365 if (!*ptr) {
366 brelse(bh);
367 goto nomem_free;
368 }
369 if (count < sb->s_blocksize)
370 memset((void *)*ptr + count, 0xff,
371 sb->s_blocksize - count);
372 brelse(bh);
373 ptr++;
374 }
375 out:
376 return 0;
377
378 nomem_free:
379 for (count = 0; count < array_size; count++)
380 kfree(sbi->s_imap[count]);
381
382 kfree(sbi->s_imap);
383 nomem:
384 sbi->s_imap = NULL;
385 sbi->s_imap_size = 0;
386 return -ENOMEM;
387 }
388
389 enum {
390 Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask, Opt_err
391 };
392
393 static const match_table_t tokens = {
394 {Opt_uid, "uid=%u"},
395 {Opt_gid, "gid=%u"},
396 {Opt_umask, "umask=%o"},
397 {Opt_dmask, "dmask=%o"},
398 {Opt_fmask, "fmask=%o"},
399 {Opt_err, NULL},
400 };
401
parse_options(char * options,struct omfs_sb_info * sbi)402 static int parse_options(char *options, struct omfs_sb_info *sbi)
403 {
404 char *p;
405 substring_t args[MAX_OPT_ARGS];
406 int option;
407
408 if (!options)
409 return 1;
410
411 while ((p = strsep(&options, ",")) != NULL) {
412 int token;
413 if (!*p)
414 continue;
415
416 token = match_token(p, tokens, args);
417 switch (token) {
418 case Opt_uid:
419 if (match_int(&args[0], &option))
420 return 0;
421 sbi->s_uid = make_kuid(current_user_ns(), option);
422 if (!uid_valid(sbi->s_uid))
423 return 0;
424 break;
425 case Opt_gid:
426 if (match_int(&args[0], &option))
427 return 0;
428 sbi->s_gid = make_kgid(current_user_ns(), option);
429 if (!gid_valid(sbi->s_gid))
430 return 0;
431 break;
432 case Opt_umask:
433 if (match_octal(&args[0], &option))
434 return 0;
435 sbi->s_fmask = sbi->s_dmask = option;
436 break;
437 case Opt_dmask:
438 if (match_octal(&args[0], &option))
439 return 0;
440 sbi->s_dmask = option;
441 break;
442 case Opt_fmask:
443 if (match_octal(&args[0], &option))
444 return 0;
445 sbi->s_fmask = option;
446 break;
447 default:
448 return 0;
449 }
450 }
451 return 1;
452 }
453
omfs_fill_super(struct super_block * sb,void * data,int silent)454 static int omfs_fill_super(struct super_block *sb, void *data, int silent)
455 {
456 struct buffer_head *bh, *bh2;
457 struct omfs_super_block *omfs_sb;
458 struct omfs_root_block *omfs_rb;
459 struct omfs_sb_info *sbi;
460 struct inode *root;
461 int ret = -EINVAL;
462
463 sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
464 if (!sbi)
465 return -ENOMEM;
466
467 sb->s_fs_info = sbi;
468
469 sbi->s_uid = current_uid();
470 sbi->s_gid = current_gid();
471 sbi->s_dmask = sbi->s_fmask = current_umask();
472
473 if (!parse_options((char *) data, sbi))
474 goto end;
475
476 sb->s_maxbytes = 0xffffffff;
477
478 sb->s_time_gran = NSEC_PER_MSEC;
479 sb->s_time_min = 0;
480 sb->s_time_max = U64_MAX / MSEC_PER_SEC;
481
482 sb_set_blocksize(sb, 0x200);
483
484 bh = sb_bread(sb, 0);
485 if (!bh)
486 goto end;
487
488 omfs_sb = (struct omfs_super_block *)bh->b_data;
489
490 if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
491 if (!silent)
492 printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
493 omfs_sb->s_magic);
494 goto out_brelse_bh;
495 }
496 sb->s_magic = OMFS_MAGIC;
497
498 sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
499 sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
500 sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
501 sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
502 sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
503 mutex_init(&sbi->s_bitmap_lock);
504
505 if (sbi->s_num_blocks > OMFS_MAX_BLOCKS) {
506 printk(KERN_ERR "omfs: sysblock number (%llx) is out of range\n",
507 (unsigned long long)sbi->s_num_blocks);
508 goto out_brelse_bh;
509 }
510
511 if (sbi->s_sys_blocksize > PAGE_SIZE) {
512 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
513 sbi->s_sys_blocksize);
514 goto out_brelse_bh;
515 }
516
517 if (sbi->s_blocksize < sbi->s_sys_blocksize ||
518 sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
519 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
520 sbi->s_blocksize);
521 goto out_brelse_bh;
522 }
523
524 /*
525 * Use sys_blocksize as the fs block since it is smaller than a
526 * page while the fs blocksize can be larger.
527 */
528 sb_set_blocksize(sb, sbi->s_sys_blocksize);
529
530 /*
531 * ...and the difference goes into a shift. sys_blocksize is always
532 * a power of two factor of blocksize.
533 */
534 sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
535 get_bitmask_order(sbi->s_sys_blocksize);
536
537 bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
538 if (!bh2)
539 goto out_brelse_bh;
540
541 omfs_rb = (struct omfs_root_block *)bh2->b_data;
542
543 sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
544 sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
545
546 if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
547 printk(KERN_ERR "omfs: block count discrepancy between "
548 "super and root blocks (%llx, %llx)\n",
549 (unsigned long long)sbi->s_num_blocks,
550 (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
551 goto out_brelse_bh2;
552 }
553
554 if (sbi->s_bitmap_ino != ~0ULL &&
555 sbi->s_bitmap_ino > sbi->s_num_blocks) {
556 printk(KERN_ERR "omfs: free space bitmap location is corrupt "
557 "(%llx, total blocks %llx)\n",
558 (unsigned long long) sbi->s_bitmap_ino,
559 (unsigned long long) sbi->s_num_blocks);
560 goto out_brelse_bh2;
561 }
562 if (sbi->s_clustersize < 1 ||
563 sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
564 printk(KERN_ERR "omfs: cluster size out of range (%d)",
565 sbi->s_clustersize);
566 goto out_brelse_bh2;
567 }
568
569 ret = omfs_get_imap(sb);
570 if (ret)
571 goto out_brelse_bh2;
572
573 sb->s_op = &omfs_sops;
574
575 root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
576 if (IS_ERR(root)) {
577 ret = PTR_ERR(root);
578 goto out_brelse_bh2;
579 }
580
581 sb->s_root = d_make_root(root);
582 if (!sb->s_root) {
583 ret = -ENOMEM;
584 goto out_brelse_bh2;
585 }
586 printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
587
588 ret = 0;
589 out_brelse_bh2:
590 brelse(bh2);
591 out_brelse_bh:
592 brelse(bh);
593 end:
594 if (ret)
595 kfree(sbi);
596 return ret;
597 }
598
omfs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)599 static struct dentry *omfs_mount(struct file_system_type *fs_type,
600 int flags, const char *dev_name, void *data)
601 {
602 return mount_bdev(fs_type, flags, dev_name, data, omfs_fill_super);
603 }
604
605 static struct file_system_type omfs_fs_type = {
606 .owner = THIS_MODULE,
607 .name = "omfs",
608 .mount = omfs_mount,
609 .kill_sb = kill_block_super,
610 .fs_flags = FS_REQUIRES_DEV,
611 };
612 MODULE_ALIAS_FS("omfs");
613
init_omfs_fs(void)614 static int __init init_omfs_fs(void)
615 {
616 return register_filesystem(&omfs_fs_type);
617 }
618
exit_omfs_fs(void)619 static void __exit exit_omfs_fs(void)
620 {
621 unregister_filesystem(&omfs_fs_type);
622 }
623
624 module_init(init_omfs_fs);
625 module_exit(exit_omfs_fs);
626