xref: /linux/fs/omfs/inode.c (revision 0ea5c948cb64bab5bc7a5516774eb8536f05aa0d)
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 	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  */
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_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 
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_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 
omfs_put_super(struct super_block * sb)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 
omfs_statfs(struct dentry * dentry,struct kstatfs * buf)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  */
omfs_show_options(struct seq_file * m,struct dentry * root)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  */
omfs_get_imap(struct super_block * sb)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 
parse_options(char * options,struct omfs_sb_info * sbi)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 
omfs_fill_super(struct super_block * sb,void * data,int silent)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 
omfs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)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 
init_omfs_fs(void)612 static int __init init_omfs_fs(void)
613 {
614 	return register_filesystem(&omfs_fs_type);
615 }
616 
exit_omfs_fs(void)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