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 MODULE_IMPORT_NS(ANDROID_GKI_VFS_EXPORT_ONLY);
24
omfs_bread(struct super_block * sb,sector_t block)25 struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)
26 {
27 struct omfs_sb_info *sbi = OMFS_SB(sb);
28 if (block >= sbi->s_num_blocks)
29 return NULL;
30
31 return sb_bread(sb, clus_to_blk(sbi, block));
32 }
33
omfs_new_inode(struct inode * dir,umode_t mode)34 struct inode *omfs_new_inode(struct inode *dir, umode_t mode)
35 {
36 struct inode *inode;
37 u64 new_block;
38 int err;
39 int len;
40 struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
41
42 inode = new_inode(dir->i_sb);
43 if (!inode)
44 return ERR_PTR(-ENOMEM);
45
46 err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
47 &new_block, &len);
48 if (err)
49 goto fail;
50
51 inode->i_ino = new_block;
52 inode_init_owner(&init_user_ns, inode, NULL, mode);
53 inode->i_mapping->a_ops = &omfs_aops;
54
55 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
56 switch (mode & S_IFMT) {
57 case S_IFDIR:
58 inode->i_op = &omfs_dir_inops;
59 inode->i_fop = &omfs_dir_operations;
60 inode->i_size = sbi->s_sys_blocksize;
61 inc_nlink(inode);
62 break;
63 case S_IFREG:
64 inode->i_op = &omfs_file_inops;
65 inode->i_fop = &omfs_file_operations;
66 inode->i_size = 0;
67 break;
68 }
69
70 insert_inode_hash(inode);
71 mark_inode_dirty(inode);
72 return inode;
73 fail:
74 make_bad_inode(inode);
75 iput(inode);
76 return ERR_PTR(err);
77 }
78
79 /*
80 * Update the header checksums for a dirty inode based on its contents.
81 * Caller is expected to hold the buffer head underlying oi and mark it
82 * dirty.
83 */
omfs_update_checksums(struct omfs_inode * oi)84 static void omfs_update_checksums(struct omfs_inode *oi)
85 {
86 int xor, i, ofs = 0, count;
87 u16 crc = 0;
88 unsigned char *ptr = (unsigned char *) oi;
89
90 count = be32_to_cpu(oi->i_head.h_body_size);
91 ofs = sizeof(struct omfs_header);
92
93 crc = crc_itu_t(crc, ptr + ofs, count);
94 oi->i_head.h_crc = cpu_to_be16(crc);
95
96 xor = ptr[0];
97 for (i = 1; i < OMFS_XOR_COUNT; i++)
98 xor ^= ptr[i];
99
100 oi->i_head.h_check_xor = xor;
101 }
102
__omfs_write_inode(struct inode * inode,int wait)103 static int __omfs_write_inode(struct inode *inode, int wait)
104 {
105 struct omfs_inode *oi;
106 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
107 struct buffer_head *bh, *bh2;
108 u64 ctime;
109 int i;
110 int ret = -EIO;
111 int sync_failed = 0;
112
113 /* get current inode since we may have written sibling ptrs etc. */
114 bh = omfs_bread(inode->i_sb, inode->i_ino);
115 if (!bh)
116 goto out;
117
118 oi = (struct omfs_inode *) bh->b_data;
119
120 oi->i_head.h_self = cpu_to_be64(inode->i_ino);
121 if (S_ISDIR(inode->i_mode))
122 oi->i_type = OMFS_DIR;
123 else if (S_ISREG(inode->i_mode))
124 oi->i_type = OMFS_FILE;
125 else {
126 printk(KERN_WARNING "omfs: unknown file type: %d\n",
127 inode->i_mode);
128 goto out_brelse;
129 }
130
131 oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
132 sizeof(struct omfs_header));
133 oi->i_head.h_version = 1;
134 oi->i_head.h_type = OMFS_INODE_NORMAL;
135 oi->i_head.h_magic = OMFS_IMAGIC;
136 oi->i_size = cpu_to_be64(inode->i_size);
137
138 ctime = inode->i_ctime.tv_sec * 1000LL +
139 ((inode->i_ctime.tv_nsec + 999)/1000);
140 oi->i_ctime = cpu_to_be64(ctime);
141
142 omfs_update_checksums(oi);
143
144 mark_buffer_dirty(bh);
145 if (wait) {
146 sync_dirty_buffer(bh);
147 if (buffer_req(bh) && !buffer_uptodate(bh))
148 sync_failed = 1;
149 }
150
151 /* if mirroring writes, copy to next fsblock */
152 for (i = 1; i < sbi->s_mirrors; i++) {
153 bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
154 if (!bh2)
155 goto out_brelse;
156
157 memcpy(bh2->b_data, bh->b_data, bh->b_size);
158 mark_buffer_dirty(bh2);
159 if (wait) {
160 sync_dirty_buffer(bh2);
161 if (buffer_req(bh2) && !buffer_uptodate(bh2))
162 sync_failed = 1;
163 }
164 brelse(bh2);
165 }
166 ret = (sync_failed) ? -EIO : 0;
167 out_brelse:
168 brelse(bh);
169 out:
170 return ret;
171 }
172
omfs_write_inode(struct inode * inode,struct writeback_control * wbc)173 static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
174 {
175 return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
176 }
177
omfs_sync_inode(struct inode * inode)178 int omfs_sync_inode(struct inode *inode)
179 {
180 return __omfs_write_inode(inode, 1);
181 }
182
183 /*
184 * called when an entry is deleted, need to clear the bits in the
185 * bitmaps.
186 */
omfs_evict_inode(struct inode * inode)187 static void omfs_evict_inode(struct inode *inode)
188 {
189 truncate_inode_pages_final(&inode->i_data);
190 clear_inode(inode);
191
192 if (inode->i_nlink)
193 return;
194
195 if (S_ISREG(inode->i_mode)) {
196 inode->i_size = 0;
197 omfs_shrink_inode(inode);
198 }
199
200 omfs_clear_range(inode->i_sb, inode->i_ino, 2);
201 }
202
omfs_iget(struct super_block * sb,ino_t ino)203 struct inode *omfs_iget(struct super_block *sb, ino_t ino)
204 {
205 struct omfs_sb_info *sbi = OMFS_SB(sb);
206 struct omfs_inode *oi;
207 struct buffer_head *bh;
208 u64 ctime;
209 unsigned long nsecs;
210 struct inode *inode;
211
212 inode = iget_locked(sb, ino);
213 if (!inode)
214 return ERR_PTR(-ENOMEM);
215 if (!(inode->i_state & I_NEW))
216 return inode;
217
218 bh = omfs_bread(inode->i_sb, ino);
219 if (!bh)
220 goto iget_failed;
221
222 oi = (struct omfs_inode *)bh->b_data;
223
224 /* check self */
225 if (ino != be64_to_cpu(oi->i_head.h_self))
226 goto fail_bh;
227
228 inode->i_uid = sbi->s_uid;
229 inode->i_gid = sbi->s_gid;
230
231 ctime = be64_to_cpu(oi->i_ctime);
232 nsecs = do_div(ctime, 1000) * 1000L;
233
234 inode->i_atime.tv_sec = ctime;
235 inode->i_mtime.tv_sec = ctime;
236 inode->i_ctime.tv_sec = ctime;
237 inode->i_atime.tv_nsec = nsecs;
238 inode->i_mtime.tv_nsec = nsecs;
239 inode->i_ctime.tv_nsec = nsecs;
240
241 inode->i_mapping->a_ops = &omfs_aops;
242
243 switch (oi->i_type) {
244 case OMFS_DIR:
245 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
246 inode->i_op = &omfs_dir_inops;
247 inode->i_fop = &omfs_dir_operations;
248 inode->i_size = sbi->s_sys_blocksize;
249 inc_nlink(inode);
250 break;
251 case OMFS_FILE:
252 inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
253 inode->i_fop = &omfs_file_operations;
254 inode->i_size = be64_to_cpu(oi->i_size);
255 break;
256 }
257 brelse(bh);
258 unlock_new_inode(inode);
259 return inode;
260 fail_bh:
261 brelse(bh);
262 iget_failed:
263 iget_failed(inode);
264 return ERR_PTR(-EIO);
265 }
266
omfs_put_super(struct super_block * sb)267 static void omfs_put_super(struct super_block *sb)
268 {
269 struct omfs_sb_info *sbi = OMFS_SB(sb);
270 kfree(sbi->s_imap);
271 kfree(sbi);
272 sb->s_fs_info = NULL;
273 }
274
omfs_statfs(struct dentry * dentry,struct kstatfs * buf)275 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
276 {
277 struct super_block *s = dentry->d_sb;
278 struct omfs_sb_info *sbi = OMFS_SB(s);
279 u64 id = huge_encode_dev(s->s_bdev->bd_dev);
280
281 buf->f_type = OMFS_MAGIC;
282 buf->f_bsize = sbi->s_blocksize;
283 buf->f_blocks = sbi->s_num_blocks;
284 buf->f_files = sbi->s_num_blocks;
285 buf->f_namelen = OMFS_NAMELEN;
286 buf->f_fsid = u64_to_fsid(id);
287
288 buf->f_bfree = buf->f_bavail = buf->f_ffree =
289 omfs_count_free(s);
290
291 return 0;
292 }
293
294 /*
295 * Display the mount options in /proc/mounts.
296 */
omfs_show_options(struct seq_file * m,struct dentry * root)297 static int omfs_show_options(struct seq_file *m, struct dentry *root)
298 {
299 struct omfs_sb_info *sbi = OMFS_SB(root->d_sb);
300 umode_t cur_umask = current_umask();
301
302 if (!uid_eq(sbi->s_uid, current_uid()))
303 seq_printf(m, ",uid=%u",
304 from_kuid_munged(&init_user_ns, sbi->s_uid));
305 if (!gid_eq(sbi->s_gid, current_gid()))
306 seq_printf(m, ",gid=%u",
307 from_kgid_munged(&init_user_ns, sbi->s_gid));
308
309 if (sbi->s_dmask == sbi->s_fmask) {
310 if (sbi->s_fmask != cur_umask)
311 seq_printf(m, ",umask=%o", sbi->s_fmask);
312 } else {
313 if (sbi->s_dmask != cur_umask)
314 seq_printf(m, ",dmask=%o", sbi->s_dmask);
315 if (sbi->s_fmask != cur_umask)
316 seq_printf(m, ",fmask=%o", sbi->s_fmask);
317 }
318
319 return 0;
320 }
321
322 static const struct super_operations omfs_sops = {
323 .write_inode = omfs_write_inode,
324 .evict_inode = omfs_evict_inode,
325 .put_super = omfs_put_super,
326 .statfs = omfs_statfs,
327 .show_options = omfs_show_options,
328 };
329
330 /*
331 * For Rio Karma, there is an on-disk free bitmap whose location is
332 * stored in the root block. For ReplayTV, there is no such free bitmap
333 * so we have to walk the tree. Both inodes and file data are allocated
334 * from the same map. This array can be big (300k) so we allocate
335 * in units of the blocksize.
336 */
omfs_get_imap(struct super_block * sb)337 static int omfs_get_imap(struct super_block *sb)
338 {
339 unsigned int bitmap_size, array_size;
340 int count;
341 struct omfs_sb_info *sbi = OMFS_SB(sb);
342 struct buffer_head *bh;
343 unsigned long **ptr;
344 sector_t block;
345
346 bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
347 array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
348
349 if (sbi->s_bitmap_ino == ~0ULL)
350 goto out;
351
352 sbi->s_imap_size = array_size;
353 sbi->s_imap = kcalloc(array_size, sizeof(unsigned long *), GFP_KERNEL);
354 if (!sbi->s_imap)
355 goto nomem;
356
357 block = clus_to_blk(sbi, sbi->s_bitmap_ino);
358 if (block >= sbi->s_num_blocks)
359 goto nomem;
360
361 ptr = sbi->s_imap;
362 for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
363 bh = sb_bread(sb, block++);
364 if (!bh)
365 goto nomem_free;
366 *ptr = kmemdup(bh->b_data, sb->s_blocksize, GFP_KERNEL);
367 if (!*ptr) {
368 brelse(bh);
369 goto nomem_free;
370 }
371 if (count < sb->s_blocksize)
372 memset((void *)*ptr + count, 0xff,
373 sb->s_blocksize - count);
374 brelse(bh);
375 ptr++;
376 }
377 out:
378 return 0;
379
380 nomem_free:
381 for (count = 0; count < array_size; count++)
382 kfree(sbi->s_imap[count]);
383
384 kfree(sbi->s_imap);
385 nomem:
386 sbi->s_imap = NULL;
387 sbi->s_imap_size = 0;
388 return -ENOMEM;
389 }
390
391 enum {
392 Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask, Opt_err
393 };
394
395 static const match_table_t tokens = {
396 {Opt_uid, "uid=%u"},
397 {Opt_gid, "gid=%u"},
398 {Opt_umask, "umask=%o"},
399 {Opt_dmask, "dmask=%o"},
400 {Opt_fmask, "fmask=%o"},
401 {Opt_err, NULL},
402 };
403
parse_options(char * options,struct omfs_sb_info * sbi)404 static int parse_options(char *options, struct omfs_sb_info *sbi)
405 {
406 char *p;
407 substring_t args[MAX_OPT_ARGS];
408 int option;
409
410 if (!options)
411 return 1;
412
413 while ((p = strsep(&options, ",")) != NULL) {
414 int token;
415 if (!*p)
416 continue;
417
418 token = match_token(p, tokens, args);
419 switch (token) {
420 case Opt_uid:
421 if (match_int(&args[0], &option))
422 return 0;
423 sbi->s_uid = make_kuid(current_user_ns(), option);
424 if (!uid_valid(sbi->s_uid))
425 return 0;
426 break;
427 case Opt_gid:
428 if (match_int(&args[0], &option))
429 return 0;
430 sbi->s_gid = make_kgid(current_user_ns(), option);
431 if (!gid_valid(sbi->s_gid))
432 return 0;
433 break;
434 case Opt_umask:
435 if (match_octal(&args[0], &option))
436 return 0;
437 sbi->s_fmask = sbi->s_dmask = option;
438 break;
439 case Opt_dmask:
440 if (match_octal(&args[0], &option))
441 return 0;
442 sbi->s_dmask = option;
443 break;
444 case Opt_fmask:
445 if (match_octal(&args[0], &option))
446 return 0;
447 sbi->s_fmask = option;
448 break;
449 default:
450 return 0;
451 }
452 }
453 return 1;
454 }
455
omfs_fill_super(struct super_block * sb,void * data,int silent)456 static int omfs_fill_super(struct super_block *sb, void *data, int silent)
457 {
458 struct buffer_head *bh, *bh2;
459 struct omfs_super_block *omfs_sb;
460 struct omfs_root_block *omfs_rb;
461 struct omfs_sb_info *sbi;
462 struct inode *root;
463 int ret = -EINVAL;
464
465 sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
466 if (!sbi)
467 return -ENOMEM;
468
469 sb->s_fs_info = sbi;
470
471 sbi->s_uid = current_uid();
472 sbi->s_gid = current_gid();
473 sbi->s_dmask = sbi->s_fmask = current_umask();
474
475 if (!parse_options((char *) data, sbi))
476 goto end;
477
478 sb->s_maxbytes = 0xffffffff;
479
480 sb->s_time_gran = NSEC_PER_MSEC;
481 sb->s_time_min = 0;
482 sb->s_time_max = U64_MAX / MSEC_PER_SEC;
483
484 sb_set_blocksize(sb, 0x200);
485
486 bh = sb_bread(sb, 0);
487 if (!bh)
488 goto end;
489
490 omfs_sb = (struct omfs_super_block *)bh->b_data;
491
492 if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
493 if (!silent)
494 printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
495 omfs_sb->s_magic);
496 goto out_brelse_bh;
497 }
498 sb->s_magic = OMFS_MAGIC;
499
500 sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
501 sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
502 sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
503 sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
504 sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
505 mutex_init(&sbi->s_bitmap_lock);
506
507 if (sbi->s_num_blocks > OMFS_MAX_BLOCKS) {
508 printk(KERN_ERR "omfs: sysblock number (%llx) is out of range\n",
509 (unsigned long long)sbi->s_num_blocks);
510 goto out_brelse_bh;
511 }
512
513 if (sbi->s_sys_blocksize > PAGE_SIZE) {
514 printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
515 sbi->s_sys_blocksize);
516 goto out_brelse_bh;
517 }
518
519 if (sbi->s_blocksize < sbi->s_sys_blocksize ||
520 sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
521 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
522 sbi->s_blocksize);
523 goto out_brelse_bh;
524 }
525
526 /*
527 * Use sys_blocksize as the fs block since it is smaller than a
528 * page while the fs blocksize can be larger.
529 */
530 sb_set_blocksize(sb, sbi->s_sys_blocksize);
531
532 /*
533 * ...and the difference goes into a shift. sys_blocksize is always
534 * a power of two factor of blocksize.
535 */
536 sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
537 get_bitmask_order(sbi->s_sys_blocksize);
538
539 bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
540 if (!bh2)
541 goto out_brelse_bh;
542
543 omfs_rb = (struct omfs_root_block *)bh2->b_data;
544
545 sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
546 sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
547
548 if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
549 printk(KERN_ERR "omfs: block count discrepancy between "
550 "super and root blocks (%llx, %llx)\n",
551 (unsigned long long)sbi->s_num_blocks,
552 (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
553 goto out_brelse_bh2;
554 }
555
556 if (sbi->s_bitmap_ino != ~0ULL &&
557 sbi->s_bitmap_ino > sbi->s_num_blocks) {
558 printk(KERN_ERR "omfs: free space bitmap location is corrupt "
559 "(%llx, total blocks %llx)\n",
560 (unsigned long long) sbi->s_bitmap_ino,
561 (unsigned long long) sbi->s_num_blocks);
562 goto out_brelse_bh2;
563 }
564 if (sbi->s_clustersize < 1 ||
565 sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
566 printk(KERN_ERR "omfs: cluster size out of range (%d)",
567 sbi->s_clustersize);
568 goto out_brelse_bh2;
569 }
570
571 ret = omfs_get_imap(sb);
572 if (ret)
573 goto out_brelse_bh2;
574
575 sb->s_op = &omfs_sops;
576
577 root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
578 if (IS_ERR(root)) {
579 ret = PTR_ERR(root);
580 goto out_brelse_bh2;
581 }
582
583 sb->s_root = d_make_root(root);
584 if (!sb->s_root) {
585 ret = -ENOMEM;
586 goto out_brelse_bh2;
587 }
588 printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
589
590 ret = 0;
591 out_brelse_bh2:
592 brelse(bh2);
593 out_brelse_bh:
594 brelse(bh);
595 end:
596 if (ret)
597 kfree(sbi);
598 return ret;
599 }
600
omfs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)601 static struct dentry *omfs_mount(struct file_system_type *fs_type,
602 int flags, const char *dev_name, void *data)
603 {
604 return mount_bdev(fs_type, flags, dev_name, data, omfs_fill_super);
605 }
606
607 static struct file_system_type omfs_fs_type = {
608 .owner = THIS_MODULE,
609 .name = "omfs",
610 .mount = omfs_mount,
611 .kill_sb = kill_block_super,
612 .fs_flags = FS_REQUIRES_DEV,
613 };
614 MODULE_ALIAS_FS("omfs");
615
init_omfs_fs(void)616 static int __init init_omfs_fs(void)
617 {
618 return register_filesystem(&omfs_fs_type);
619 }
620
exit_omfs_fs(void)621 static void __exit exit_omfs_fs(void)
622 {
623 unregister_filesystem(&omfs_fs_type);
624 }
625
626 module_init(init_omfs_fs);
627 module_exit(exit_omfs_fs);
628