xref: /openbmc/linux/fs/omfs/inode.c (revision 9ac8d3fb)
1 /*
2  * Optimized MPEG FS - inode and super operations.
3  * Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>
4  * Released under GPL v2.
5  */
6 #include <linux/version.h>
7 #include <linux/module.h>
8 #include <linux/sched.h>
9 #include <linux/fs.h>
10 #include <linux/vfs.h>
11 #include <linux/parser.h>
12 #include <linux/buffer_head.h>
13 #include <linux/vmalloc.h>
14 #include <linux/crc-itu-t.h>
15 #include "omfs.h"
16 
17 MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
18 MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
19 MODULE_LICENSE("GPL");
20 
21 struct inode *omfs_new_inode(struct inode *dir, int mode)
22 {
23 	struct inode *inode;
24 	u64 new_block;
25 	int err;
26 	int len;
27 	struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
28 
29 	inode = new_inode(dir->i_sb);
30 	if (!inode)
31 		return ERR_PTR(-ENOMEM);
32 
33 	err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
34 			&new_block, &len);
35 	if (err)
36 		goto fail;
37 
38 	inode->i_ino = new_block;
39 	inode->i_mode = mode;
40 	inode->i_uid = current->fsuid;
41 	inode->i_gid = current->fsgid;
42 	inode->i_blocks = 0;
43 	inode->i_mapping->a_ops = &omfs_aops;
44 
45 	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
46 	switch (mode & S_IFMT) {
47 	case S_IFDIR:
48 		inode->i_op = &omfs_dir_inops;
49 		inode->i_fop = &omfs_dir_operations;
50 		inode->i_size = sbi->s_sys_blocksize;
51 		inc_nlink(inode);
52 		break;
53 	case S_IFREG:
54 		inode->i_op = &omfs_file_inops;
55 		inode->i_fop = &omfs_file_operations;
56 		inode->i_size = 0;
57 		break;
58 	}
59 
60 	insert_inode_hash(inode);
61 	mark_inode_dirty(inode);
62 	return inode;
63 fail:
64 	make_bad_inode(inode);
65 	iput(inode);
66 	return ERR_PTR(err);
67 }
68 
69 /*
70  * Update the header checksums for a dirty inode based on its contents.
71  * Caller is expected to hold the buffer head underlying oi and mark it
72  * dirty.
73  */
74 static void omfs_update_checksums(struct omfs_inode *oi)
75 {
76 	int xor, i, ofs = 0, count;
77 	u16 crc = 0;
78 	unsigned char *ptr = (unsigned char *) oi;
79 
80 	count = be32_to_cpu(oi->i_head.h_body_size);
81 	ofs = sizeof(struct omfs_header);
82 
83 	crc = crc_itu_t(crc, ptr + ofs, count);
84 	oi->i_head.h_crc = cpu_to_be16(crc);
85 
86 	xor = ptr[0];
87 	for (i = 1; i < OMFS_XOR_COUNT; i++)
88 		xor ^= ptr[i];
89 
90 	oi->i_head.h_check_xor = xor;
91 }
92 
93 static int omfs_write_inode(struct inode *inode, int wait)
94 {
95 	struct omfs_inode *oi;
96 	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
97 	struct buffer_head *bh, *bh2;
98 	unsigned int block;
99 	u64 ctime;
100 	int i;
101 	int ret = -EIO;
102 	int sync_failed = 0;
103 
104 	/* get current inode since we may have written sibling ptrs etc. */
105 	block = clus_to_blk(sbi, inode->i_ino);
106 	bh = sb_bread(inode->i_sb, block);
107 	if (!bh)
108 		goto out;
109 
110 	oi = (struct omfs_inode *) bh->b_data;
111 
112 	oi->i_head.h_self = cpu_to_be64(inode->i_ino);
113 	if (S_ISDIR(inode->i_mode))
114 		oi->i_type = OMFS_DIR;
115 	else if (S_ISREG(inode->i_mode))
116 		oi->i_type = OMFS_FILE;
117 	else {
118 		printk(KERN_WARNING "omfs: unknown file type: %d\n",
119 			inode->i_mode);
120 		goto out_brelse;
121 	}
122 
123 	oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
124 		sizeof(struct omfs_header));
125 	oi->i_head.h_version = 1;
126 	oi->i_head.h_type = OMFS_INODE_NORMAL;
127 	oi->i_head.h_magic = OMFS_IMAGIC;
128 	oi->i_size = cpu_to_be64(inode->i_size);
129 
130 	ctime = inode->i_ctime.tv_sec * 1000LL +
131 		((inode->i_ctime.tv_nsec + 999)/1000);
132 	oi->i_ctime = cpu_to_be64(ctime);
133 
134 	omfs_update_checksums(oi);
135 
136 	mark_buffer_dirty(bh);
137 	if (wait) {
138 		sync_dirty_buffer(bh);
139 		if (buffer_req(bh) && !buffer_uptodate(bh))
140 			sync_failed = 1;
141 	}
142 
143 	/* if mirroring writes, copy to next fsblock */
144 	for (i = 1; i < sbi->s_mirrors; i++) {
145 		bh2 = sb_bread(inode->i_sb, block + i *
146 			(sbi->s_blocksize / sbi->s_sys_blocksize));
147 		if (!bh2)
148 			goto out_brelse;
149 
150 		memcpy(bh2->b_data, bh->b_data, bh->b_size);
151 		mark_buffer_dirty(bh2);
152 		if (wait) {
153 			sync_dirty_buffer(bh2);
154 			if (buffer_req(bh2) && !buffer_uptodate(bh2))
155 				sync_failed = 1;
156 		}
157 		brelse(bh2);
158 	}
159 	ret = (sync_failed) ? -EIO : 0;
160 out_brelse:
161 	brelse(bh);
162 out:
163 	return ret;
164 }
165 
166 int omfs_sync_inode(struct inode *inode)
167 {
168 	return omfs_write_inode(inode, 1);
169 }
170 
171 /*
172  * called when an entry is deleted, need to clear the bits in the
173  * bitmaps.
174  */
175 static void omfs_delete_inode(struct inode *inode)
176 {
177 	truncate_inode_pages(&inode->i_data, 0);
178 
179 	if (S_ISREG(inode->i_mode)) {
180 		inode->i_size = 0;
181 		omfs_shrink_inode(inode);
182 	}
183 
184 	omfs_clear_range(inode->i_sb, inode->i_ino, 2);
185 	clear_inode(inode);
186 }
187 
188 struct inode *omfs_iget(struct super_block *sb, ino_t ino)
189 {
190 	struct omfs_sb_info *sbi = OMFS_SB(sb);
191 	struct omfs_inode *oi;
192 	struct buffer_head *bh;
193 	unsigned int block;
194 	u64 ctime;
195 	unsigned long nsecs;
196 	struct inode *inode;
197 
198 	inode = iget_locked(sb, ino);
199 	if (!inode)
200 		return ERR_PTR(-ENOMEM);
201 	if (!(inode->i_state & I_NEW))
202 		return inode;
203 
204 	block = clus_to_blk(sbi, ino);
205 	bh = sb_bread(inode->i_sb, block);
206 	if (!bh)
207 		goto iget_failed;
208 
209 	oi = (struct omfs_inode *)bh->b_data;
210 
211 	/* check self */
212 	if (ino != be64_to_cpu(oi->i_head.h_self))
213 		goto fail_bh;
214 
215 	inode->i_uid = sbi->s_uid;
216 	inode->i_gid = sbi->s_gid;
217 
218 	ctime = be64_to_cpu(oi->i_ctime);
219 	nsecs = do_div(ctime, 1000) * 1000L;
220 
221 	inode->i_atime.tv_sec = ctime;
222 	inode->i_mtime.tv_sec = ctime;
223 	inode->i_ctime.tv_sec = ctime;
224 	inode->i_atime.tv_nsec = nsecs;
225 	inode->i_mtime.tv_nsec = nsecs;
226 	inode->i_ctime.tv_nsec = nsecs;
227 
228 	inode->i_mapping->a_ops = &omfs_aops;
229 
230 	switch (oi->i_type) {
231 	case OMFS_DIR:
232 		inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
233 		inode->i_op = &omfs_dir_inops;
234 		inode->i_fop = &omfs_dir_operations;
235 		inode->i_size = sbi->s_sys_blocksize;
236 		inc_nlink(inode);
237 		break;
238 	case OMFS_FILE:
239 		inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
240 		inode->i_fop = &omfs_file_operations;
241 		inode->i_size = be64_to_cpu(oi->i_size);
242 		break;
243 	}
244 	brelse(bh);
245 	unlock_new_inode(inode);
246 	return inode;
247 fail_bh:
248 	brelse(bh);
249 iget_failed:
250 	iget_failed(inode);
251 	return ERR_PTR(-EIO);
252 }
253 
254 static void omfs_put_super(struct super_block *sb)
255 {
256 	struct omfs_sb_info *sbi = OMFS_SB(sb);
257 	kfree(sbi->s_imap);
258 	kfree(sbi);
259 	sb->s_fs_info = NULL;
260 }
261 
262 static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
263 {
264 	struct super_block *s = dentry->d_sb;
265 	struct omfs_sb_info *sbi = OMFS_SB(s);
266 	buf->f_type = OMFS_MAGIC;
267 	buf->f_bsize = sbi->s_blocksize;
268 	buf->f_blocks = sbi->s_num_blocks;
269 	buf->f_files = sbi->s_num_blocks;
270 	buf->f_namelen = OMFS_NAMELEN;
271 
272 	buf->f_bfree = buf->f_bavail = buf->f_ffree =
273 		omfs_count_free(s);
274 	return 0;
275 }
276 
277 static struct super_operations omfs_sops = {
278 	.write_inode	= omfs_write_inode,
279 	.delete_inode	= omfs_delete_inode,
280 	.put_super	= omfs_put_super,
281 	.statfs		= omfs_statfs,
282 	.show_options	= generic_show_options,
283 };
284 
285 /*
286  * For Rio Karma, there is an on-disk free bitmap whose location is
287  * stored in the root block.  For ReplayTV, there is no such free bitmap
288  * so we have to walk the tree.  Both inodes and file data are allocated
289  * from the same map.  This array can be big (300k) so we allocate
290  * in units of the blocksize.
291  */
292 static int omfs_get_imap(struct super_block *sb)
293 {
294 	int bitmap_size;
295 	int array_size;
296 	int count;
297 	struct omfs_sb_info *sbi = OMFS_SB(sb);
298 	struct buffer_head *bh;
299 	unsigned long **ptr;
300 	sector_t block;
301 
302 	bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
303 	array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
304 
305 	if (sbi->s_bitmap_ino == ~0ULL)
306 		goto out;
307 
308 	sbi->s_imap_size = array_size;
309 	sbi->s_imap = kzalloc(array_size * sizeof(unsigned long *), GFP_KERNEL);
310 	if (!sbi->s_imap)
311 		goto nomem;
312 
313 	block = clus_to_blk(sbi, sbi->s_bitmap_ino);
314 	ptr = sbi->s_imap;
315 	for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
316 		bh = sb_bread(sb, block++);
317 		if (!bh)
318 			goto nomem_free;
319 		*ptr = kmalloc(sb->s_blocksize, GFP_KERNEL);
320 		if (!*ptr) {
321 			brelse(bh);
322 			goto nomem_free;
323 		}
324 		memcpy(*ptr, bh->b_data, sb->s_blocksize);
325 		if (count < sb->s_blocksize)
326 			memset((void *)*ptr + count, 0xff,
327 				sb->s_blocksize - count);
328 		brelse(bh);
329 		ptr++;
330 	}
331 out:
332 	return 0;
333 
334 nomem_free:
335 	for (count = 0; count < array_size; count++)
336 		kfree(sbi->s_imap[count]);
337 
338 	kfree(sbi->s_imap);
339 nomem:
340 	sbi->s_imap = NULL;
341 	sbi->s_imap_size = 0;
342 	return -ENOMEM;
343 }
344 
345 enum {
346 	Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask
347 };
348 
349 static const match_table_t tokens = {
350 	{Opt_uid, "uid=%u"},
351 	{Opt_gid, "gid=%u"},
352 	{Opt_umask, "umask=%o"},
353 	{Opt_dmask, "dmask=%o"},
354 	{Opt_fmask, "fmask=%o"},
355 };
356 
357 static int parse_options(char *options, struct omfs_sb_info *sbi)
358 {
359 	char *p;
360 	substring_t args[MAX_OPT_ARGS];
361 	int option;
362 
363 	if (!options)
364 		return 1;
365 
366 	while ((p = strsep(&options, ",")) != NULL) {
367 		int token;
368 		if (!*p)
369 			continue;
370 
371 		token = match_token(p, tokens, args);
372 		switch (token) {
373 		case Opt_uid:
374 			if (match_int(&args[0], &option))
375 				return 0;
376 			sbi->s_uid = option;
377 			break;
378 		case Opt_gid:
379 			if (match_int(&args[0], &option))
380 				return 0;
381 			sbi->s_gid = option;
382 			break;
383 		case Opt_umask:
384 			if (match_octal(&args[0], &option))
385 				return 0;
386 			sbi->s_fmask = sbi->s_dmask = option;
387 			break;
388 		case Opt_dmask:
389 			if (match_octal(&args[0], &option))
390 				return 0;
391 			sbi->s_dmask = option;
392 			break;
393 		case Opt_fmask:
394 			if (match_octal(&args[0], &option))
395 				return 0;
396 			sbi->s_fmask = option;
397 			break;
398 		default:
399 			return 0;
400 		}
401 	}
402 	return 1;
403 }
404 
405 static int omfs_fill_super(struct super_block *sb, void *data, int silent)
406 {
407 	struct buffer_head *bh, *bh2;
408 	struct omfs_super_block *omfs_sb;
409 	struct omfs_root_block *omfs_rb;
410 	struct omfs_sb_info *sbi;
411 	struct inode *root;
412 	sector_t start;
413 	int ret = -EINVAL;
414 
415 	save_mount_options(sb, (char *) data);
416 
417 	sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
418 	if (!sbi)
419 		return -ENOMEM;
420 
421 	sb->s_fs_info = sbi;
422 
423 	sbi->s_uid = current->uid;
424 	sbi->s_gid = current->gid;
425 	sbi->s_dmask = sbi->s_fmask = current->fs->umask;
426 
427 	if (!parse_options((char *) data, sbi))
428 		goto end;
429 
430 	sb->s_maxbytes = 0xffffffff;
431 
432 	sb_set_blocksize(sb, 0x200);
433 
434 	bh = sb_bread(sb, 0);
435 	if (!bh)
436 		goto end;
437 
438 	omfs_sb = (struct omfs_super_block *)bh->b_data;
439 
440 	if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
441 		if (!silent)
442 			printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
443 				   omfs_sb->s_magic);
444 		goto out_brelse_bh;
445 	}
446 	sb->s_magic = OMFS_MAGIC;
447 
448 	sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
449 	sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
450 	sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
451 	sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
452 	sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
453 	mutex_init(&sbi->s_bitmap_lock);
454 
455 	if (sbi->s_sys_blocksize > PAGE_SIZE) {
456 		printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
457 			sbi->s_sys_blocksize);
458 		goto out_brelse_bh;
459 	}
460 
461 	if (sbi->s_blocksize < sbi->s_sys_blocksize ||
462 	    sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
463 		printk(KERN_ERR "omfs: block size (%d) is out of range\n",
464 			sbi->s_blocksize);
465 		goto out_brelse_bh;
466 	}
467 
468 	/*
469 	 * Use sys_blocksize as the fs block since it is smaller than a
470 	 * page while the fs blocksize can be larger.
471 	 */
472 	sb_set_blocksize(sb, sbi->s_sys_blocksize);
473 
474 	/*
475 	 * ...and the difference goes into a shift.  sys_blocksize is always
476 	 * a power of two factor of blocksize.
477 	 */
478 	sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
479 		get_bitmask_order(sbi->s_sys_blocksize);
480 
481 	start = clus_to_blk(sbi, be64_to_cpu(omfs_sb->s_root_block));
482 	bh2 = sb_bread(sb, start);
483 	if (!bh2)
484 		goto out_brelse_bh;
485 
486 	omfs_rb = (struct omfs_root_block *)bh2->b_data;
487 
488 	sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
489 	sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
490 
491 	if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
492 		printk(KERN_ERR "omfs: block count discrepancy between "
493 			"super and root blocks (%llx, %llx)\n",
494 			(unsigned long long)sbi->s_num_blocks,
495 			(unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
496 		goto out_brelse_bh2;
497 	}
498 
499 	ret = omfs_get_imap(sb);
500 	if (ret)
501 		goto out_brelse_bh2;
502 
503 	sb->s_op = &omfs_sops;
504 
505 	root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
506 	if (IS_ERR(root)) {
507 		ret = PTR_ERR(root);
508 		goto out_brelse_bh2;
509 	}
510 
511 	sb->s_root = d_alloc_root(root);
512 	if (!sb->s_root) {
513 		iput(root);
514 		goto out_brelse_bh2;
515 	}
516 	printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
517 
518 	ret = 0;
519 out_brelse_bh2:
520 	brelse(bh2);
521 out_brelse_bh:
522 	brelse(bh);
523 end:
524 	return ret;
525 }
526 
527 static int omfs_get_sb(struct file_system_type *fs_type,
528 			int flags, const char *dev_name,
529 			void *data, struct vfsmount *m)
530 {
531 	return get_sb_bdev(fs_type, flags, dev_name, data, omfs_fill_super, m);
532 }
533 
534 static struct file_system_type omfs_fs_type = {
535 	.owner = THIS_MODULE,
536 	.name = "omfs",
537 	.get_sb = omfs_get_sb,
538 	.kill_sb = kill_block_super,
539 	.fs_flags = FS_REQUIRES_DEV,
540 };
541 
542 static int __init init_omfs_fs(void)
543 {
544 	return register_filesystem(&omfs_fs_type);
545 }
546 
547 static void __exit exit_omfs_fs(void)
548 {
549 	unregister_filesystem(&omfs_fs_type);
550 }
551 
552 module_init(init_omfs_fs);
553 module_exit(exit_omfs_fs);
554