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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Optimized MPEG FS - inode and super operations.
4 * Copyright (C) 2006 Bob Copeland <[email protected]>
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/buffer_head.h>
13#include <linux/vmalloc.h>
14#include <linux/writeback.h>
15#include <linux/seq_file.h>
16#include <linux/crc-itu-t.h>
17#include <linux/fs_struct.h>
18#include <linux/fs_context.h>
19#include <linux/fs_parser.h>
20#include "omfs.h"
21
22MODULE_AUTHOR("Bob Copeland <[email protected]>");
23MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
24MODULE_LICENSE("GPL");
25
26struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)
27{
28 struct omfs_sb_info *sbi = OMFS_SB(sb);
29 if (block >= sbi->s_num_blocks)
30 return NULL;
31
32 return sb_bread(sb, clus_to_blk(sbi, block));
33}
34
35struct inode *omfs_new_inode(struct inode *dir, umode_t mode)
36{
37 struct inode *inode;
38 u64 new_block;
39 int err;
40 int len;
41 struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
42
43 inode = new_inode(dir->i_sb);
44 if (!inode)
45 return ERR_PTR(-ENOMEM);
46
47 err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
48 &new_block, &len);
49 if (err)
50 goto fail;
51
52 inode->i_ino = new_block;
53 inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
54 inode->i_mapping->a_ops = &omfs_aops;
55
56 simple_inode_init_ts(inode);
57 switch (mode & S_IFMT) {
58 case S_IFDIR:
59 inode->i_op = &omfs_dir_inops;
60 inode->i_fop = &omfs_dir_operations;
61 inode->i_size = sbi->s_sys_blocksize;
62 inc_nlink(inode);
63 break;
64 case S_IFREG:
65 inode->i_op = &omfs_file_inops;
66 inode->i_fop = &omfs_file_operations;
67 inode->i_size = 0;
68 break;
69 }
70
71 insert_inode_hash(inode);
72 mark_inode_dirty(inode);
73 return inode;
74fail:
75 make_bad_inode(inode);
76 iput(inode);
77 return ERR_PTR(err);
78}
79
80/*
81 * Update the header checksums for a dirty inode based on its contents.
82 * Caller is expected to hold the buffer head underlying oi and mark it
83 * dirty.
84 */
85static void omfs_update_checksums(struct omfs_inode *oi)
86{
87 int xor, i, ofs = 0, count;
88 u16 crc = 0;
89 unsigned char *ptr = (unsigned char *) oi;
90
91 count = be32_to_cpu(oi->i_head.h_body_size);
92 ofs = sizeof(struct omfs_header);
93
94 crc = crc_itu_t(crc, ptr + ofs, count);
95 oi->i_head.h_crc = cpu_to_be16(crc);
96
97 xor = ptr[0];
98 for (i = 1; i < OMFS_XOR_COUNT; i++)
99 xor ^= ptr[i];
100
101 oi->i_head.h_check_xor = xor;
102}
103
104static int __omfs_write_inode(struct inode *inode, int wait)
105{
106 struct omfs_inode *oi;
107 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
108 struct buffer_head *bh, *bh2;
109 u64 ctime;
110 int i;
111 int ret = -EIO;
112 int sync_failed = 0;
113
114 /* get current inode since we may have written sibling ptrs etc. */
115 bh = omfs_bread(inode->i_sb, inode->i_ino);
116 if (!bh)
117 goto out;
118
119 oi = (struct omfs_inode *) bh->b_data;
120
121 oi->i_head.h_self = cpu_to_be64(inode->i_ino);
122 if (S_ISDIR(inode->i_mode))
123 oi->i_type = OMFS_DIR;
124 else if (S_ISREG(inode->i_mode))
125 oi->i_type = OMFS_FILE;
126 else {
127 printk(KERN_WARNING "omfs: unknown file type: %d\n",
128 inode->i_mode);
129 goto out_brelse;
130 }
131
132 oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
133 sizeof(struct omfs_header));
134 oi->i_head.h_version = 1;
135 oi->i_head.h_type = OMFS_INODE_NORMAL;
136 oi->i_head.h_magic = OMFS_IMAGIC;
137 oi->i_size = cpu_to_be64(inode->i_size);
138
139 ctime = inode_get_ctime_sec(inode) * 1000LL +
140 ((inode_get_ctime_nsec(inode) + 999)/1000);
141 oi->i_ctime = cpu_to_be64(ctime);
142
143 omfs_update_checksums(oi);
144
145 mark_buffer_dirty(bh);
146 if (wait) {
147 sync_dirty_buffer(bh);
148 if (buffer_write_io_error(bh))
149 sync_failed = 1;
150 }
151
152 /* if mirroring writes, copy to next fsblock */
153 for (i = 1; i < sbi->s_mirrors; i++) {
154 bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
155 if (!bh2)
156 goto out_brelse;
157
158 memcpy(bh2->b_data, bh->b_data, bh->b_size);
159 mark_buffer_dirty(bh2);
160 if (wait) {
161 sync_dirty_buffer(bh2);
162 if (buffer_write_io_error(bh2))
163 sync_failed = 1;
164 }
165 brelse(bh2);
166 }
167 ret = (sync_failed) ? -EIO : 0;
168out_brelse:
169 brelse(bh);
170out:
171 return ret;
172}
173
174static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
175{
176 return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
177}
178
179int omfs_sync_inode(struct inode *inode)
180{
181 return __omfs_write_inode(inode, 1);
182}
183
184/*
185 * called when an entry is deleted, need to clear the bits in the
186 * bitmaps.
187 */
188static void omfs_evict_inode(struct inode *inode)
189{
190 truncate_inode_pages_final(&inode->i_data);
191 clear_inode(inode);
192
193 if (inode->i_nlink)
194 return;
195
196 if (S_ISREG(inode->i_mode)) {
197 inode->i_size = 0;
198 omfs_shrink_inode(inode);
199 }
200
201 omfs_clear_range(inode->i_sb, inode->i_ino, 2);
202}
203
204struct inode *omfs_iget(struct super_block *sb, ino_t ino)
205{
206 struct omfs_sb_info *sbi = OMFS_SB(sb);
207 struct omfs_inode *oi;
208 struct buffer_head *bh;
209 u64 ctime;
210 unsigned long nsecs;
211 struct inode *inode;
212
213 inode = iget_locked(sb, ino);
214 if (!inode)
215 return ERR_PTR(-ENOMEM);
216 if (!(inode_state_read_once(inode) & I_NEW))
217 return inode;
218
219 bh = omfs_bread(inode->i_sb, ino);
220 if (!bh)
221 goto iget_failed;
222
223 oi = (struct omfs_inode *)bh->b_data;
224
225 /* check self */
226 if (ino != be64_to_cpu(oi->i_head.h_self))
227 goto fail_bh;
228
229 inode->i_uid = sbi->s_uid;
230 inode->i_gid = sbi->s_gid;
231
232 ctime = be64_to_cpu(oi->i_ctime);
233 nsecs = do_div(ctime, 1000) * 1000L;
234
235 inode_set_atime(inode, ctime, nsecs);
236 inode_set_mtime(inode, ctime, nsecs);
237 inode_set_ctime(inode, ctime, 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;
258fail_bh:
259 brelse(bh);
260iget_failed:
261 iget_failed(inode);
262 return ERR_PTR(-EIO);
263}
264
265static 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
273static 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 */
295static 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
320static 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 */
335static 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 }
375out:
376 return 0;
377
378nomem_free:
379 for (count = 0; count < array_size; count++)
380 kfree(sbi->s_imap[count]);
381
382 kfree(sbi->s_imap);
383nomem:
384 sbi->s_imap = NULL;
385 sbi->s_imap_size = 0;
386 return -ENOMEM;
387}
388
389struct omfs_mount_options {
390 kuid_t s_uid;
391 kgid_t s_gid;
392 int s_dmask;
393 int s_fmask;
394};
395
396enum {
397 Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask,
398};
399
400static const struct fs_parameter_spec omfs_param_spec[] = {
401 fsparam_uid ("uid", Opt_uid),
402 fsparam_gid ("gid", Opt_gid),
403 fsparam_u32oct ("umask", Opt_umask),
404 fsparam_u32oct ("dmask", Opt_dmask),
405 fsparam_u32oct ("fmask", Opt_fmask),
406 {}
407};
408
409static int
410omfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
411{
412 struct omfs_mount_options *opts = fc->fs_private;
413 int token;
414 struct fs_parse_result result;
415
416 /* All options are ignored on remount */
417 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE)
418 return 0;
419
420 token = fs_parse(fc, omfs_param_spec, param, &result);
421 if (token < 0)
422 return token;
423
424 switch (token) {
425 case Opt_uid:
426 opts->s_uid = result.uid;
427 break;
428 case Opt_gid:
429 opts->s_gid = result.gid;
430 break;
431 case Opt_umask:
432 opts->s_fmask = opts->s_dmask = result.uint_32;
433 break;
434 case Opt_dmask:
435 opts->s_dmask = result.uint_32;
436 break;
437 case Opt_fmask:
438 opts->s_fmask = result.uint_32;
439 break;
440 default:
441 return -EINVAL;
442 }
443
444 return 0;
445}
446
447static void
448omfs_set_options(struct omfs_sb_info *sbi, struct omfs_mount_options *opts)
449{
450 sbi->s_uid = opts->s_uid;
451 sbi->s_gid = opts->s_gid;
452 sbi->s_dmask = opts->s_dmask;
453 sbi->s_fmask = opts->s_fmask;
454}
455
456static int omfs_fill_super(struct super_block *sb, struct fs_context *fc)
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 struct omfs_mount_options *parsed_opts = fc->fs_private;
464 int ret = -EINVAL;
465 int silent = fc->sb_flags & SB_SILENT;
466
467 sbi = kzalloc_obj(struct omfs_sb_info);
468 if (!sbi)
469 return -ENOMEM;
470
471 sb->s_fs_info = sbi;
472
473 omfs_set_options(sbi, parsed_opts);
474
475 sb->s_maxbytes = 0xffffffff;
476
477 sb->s_time_gran = NSEC_PER_MSEC;
478 sb->s_time_min = 0;
479 sb->s_time_max = U64_MAX / MSEC_PER_SEC;
480
481 if (!sb_set_blocksize(sb, 0x200))
482 goto end;
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_sys_blocksize < OMFS_DIR_START) {
518 printk(KERN_ERR "omfs: sysblock size (%d) is too small\n",
519 sbi->s_sys_blocksize);
520 goto out_brelse_bh;
521 }
522
523 if (sbi->s_blocksize < sbi->s_sys_blocksize ||
524 sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
525 printk(KERN_ERR "omfs: block size (%d) is out of range\n",
526 sbi->s_blocksize);
527 goto out_brelse_bh;
528 }
529
530 /*
531 * Use sys_blocksize as the fs block since it is smaller than a
532 * page while the fs blocksize can be larger.
533 */
534 if (!sb_set_blocksize(sb, sbi->s_sys_blocksize))
535 goto out_brelse_bh;
536
537 /*
538 * ...and the difference goes into a shift. sys_blocksize is always
539 * a power of two factor of blocksize.
540 */
541 sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
542 get_bitmask_order(sbi->s_sys_blocksize);
543
544 bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
545 if (!bh2)
546 goto out_brelse_bh;
547
548 omfs_rb = (struct omfs_root_block *)bh2->b_data;
549
550 sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
551 sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
552
553 if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
554 printk(KERN_ERR "omfs: block count discrepancy between "
555 "super and root blocks (%llx, %llx)\n",
556 (unsigned long long)sbi->s_num_blocks,
557 (unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
558 goto out_brelse_bh2;
559 }
560
561 if (sbi->s_bitmap_ino != ~0ULL &&
562 sbi->s_bitmap_ino > sbi->s_num_blocks) {
563 printk(KERN_ERR "omfs: free space bitmap location is corrupt "
564 "(%llx, total blocks %llx)\n",
565 (unsigned long long) sbi->s_bitmap_ino,
566 (unsigned long long) sbi->s_num_blocks);
567 goto out_brelse_bh2;
568 }
569 if (sbi->s_clustersize < 1 ||
570 sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
571 printk(KERN_ERR "omfs: cluster size out of range (%d)",
572 sbi->s_clustersize);
573 goto out_brelse_bh2;
574 }
575
576 ret = omfs_get_imap(sb);
577 if (ret)
578 goto out_brelse_bh2;
579
580 sb->s_op = &omfs_sops;
581
582 root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
583 if (IS_ERR(root)) {
584 ret = PTR_ERR(root);
585 goto out_brelse_bh2;
586 }
587
588 sb->s_root = d_make_root(root);
589 if (!sb->s_root) {
590 ret = -ENOMEM;
591 goto out_brelse_bh2;
592 }
593 printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
594
595 ret = 0;
596out_brelse_bh2:
597 brelse(bh2);
598out_brelse_bh:
599 brelse(bh);
600end:
601 if (ret)
602 kfree(sbi);
603 return ret;
604}
605
606static int omfs_get_tree(struct fs_context *fc)
607{
608 return get_tree_bdev(fc, omfs_fill_super);
609}
610
611static void omfs_free_fc(struct fs_context *fc);
612
613static const struct fs_context_operations omfs_context_ops = {
614 .parse_param = omfs_parse_param,
615 .get_tree = omfs_get_tree,
616 .free = omfs_free_fc,
617};
618
619static int omfs_init_fs_context(struct fs_context *fc)
620{
621 struct omfs_mount_options *opts;
622
623 opts = kzalloc_obj(*opts);
624 if (!opts)
625 return -ENOMEM;
626
627 /* Set mount options defaults */
628 opts->s_uid = current_uid();
629 opts->s_gid = current_gid();
630 opts->s_dmask = opts->s_fmask = current_umask();
631
632 fc->fs_private = opts;
633 fc->ops = &omfs_context_ops;
634
635 return 0;
636}
637
638static void omfs_free_fc(struct fs_context *fc)
639{
640 kfree(fc->fs_private);
641}
642
643static struct file_system_type omfs_fs_type = {
644 .owner = THIS_MODULE,
645 .name = "omfs",
646 .kill_sb = kill_block_super,
647 .fs_flags = FS_REQUIRES_DEV,
648 .init_fs_context = omfs_init_fs_context,
649 .parameters = omfs_param_spec,
650};
651MODULE_ALIAS_FS("omfs");
652
653static int __init init_omfs_fs(void)
654{
655 return register_filesystem(&omfs_fs_type);
656}
657
658static void __exit exit_omfs_fs(void)
659{
660 unregister_filesystem(&omfs_fs_type);
661}
662
663module_init(init_omfs_fs);
664module_exit(exit_omfs_fs);