xref: /linux/fs/minix/inode.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
1 /*
2  *  linux/fs/minix/inode.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  *
6  *  Copyright (C) 1996  Gertjan van Wingerde
7  *	Minix V2 fs support.
8  *
9  *  Modified for 680x0 by Andreas Schwab
10  *  Updated to filesystem version 3 by Daniel Aragones
11  */
12 
13 #include <linux/module.h>
14 #include "minix.h"
15 #include <linux/buffer_head.h>
16 #include <linux/slab.h>
17 #include <linux/init.h>
18 #include <linux/highuid.h>
19 #include <linux/vfs.h>
20 #include <linux/writeback.h>
21 
22 static int minix_write_inode(struct inode *inode,
23 		struct writeback_control *wbc);
24 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf);
25 static int minix_remount (struct super_block * sb, int * flags, char * data);
26 
27 static void minix_evict_inode(struct inode *inode)
28 {
29 	truncate_inode_pages(&inode->i_data, 0);
30 	if (!inode->i_nlink) {
31 		inode->i_size = 0;
32 		minix_truncate(inode);
33 	}
34 	invalidate_inode_buffers(inode);
35 	clear_inode(inode);
36 	if (!inode->i_nlink)
37 		minix_free_inode(inode);
38 }
39 
40 static void minix_put_super(struct super_block *sb)
41 {
42 	int i;
43 	struct minix_sb_info *sbi = minix_sb(sb);
44 
45 	if (!(sb->s_flags & MS_RDONLY)) {
46 		if (sbi->s_version != MINIX_V3)	 /* s_state is now out from V3 sb */
47 			sbi->s_ms->s_state = sbi->s_mount_state;
48 		mark_buffer_dirty(sbi->s_sbh);
49 	}
50 	for (i = 0; i < sbi->s_imap_blocks; i++)
51 		brelse(sbi->s_imap[i]);
52 	for (i = 0; i < sbi->s_zmap_blocks; i++)
53 		brelse(sbi->s_zmap[i]);
54 	brelse (sbi->s_sbh);
55 	kfree(sbi->s_imap);
56 	sb->s_fs_info = NULL;
57 	kfree(sbi);
58 }
59 
60 static struct kmem_cache * minix_inode_cachep;
61 
62 static struct inode *minix_alloc_inode(struct super_block *sb)
63 {
64 	struct minix_inode_info *ei;
65 	ei = (struct minix_inode_info *)kmem_cache_alloc(minix_inode_cachep, GFP_KERNEL);
66 	if (!ei)
67 		return NULL;
68 	return &ei->vfs_inode;
69 }
70 
71 static void minix_i_callback(struct rcu_head *head)
72 {
73 	struct inode *inode = container_of(head, struct inode, i_rcu);
74 	kmem_cache_free(minix_inode_cachep, minix_i(inode));
75 }
76 
77 static void minix_destroy_inode(struct inode *inode)
78 {
79 	call_rcu(&inode->i_rcu, minix_i_callback);
80 }
81 
82 static void init_once(void *foo)
83 {
84 	struct minix_inode_info *ei = (struct minix_inode_info *) foo;
85 
86 	inode_init_once(&ei->vfs_inode);
87 }
88 
89 static int init_inodecache(void)
90 {
91 	minix_inode_cachep = kmem_cache_create("minix_inode_cache",
92 					     sizeof(struct minix_inode_info),
93 					     0, (SLAB_RECLAIM_ACCOUNT|
94 						SLAB_MEM_SPREAD),
95 					     init_once);
96 	if (minix_inode_cachep == NULL)
97 		return -ENOMEM;
98 	return 0;
99 }
100 
101 static void destroy_inodecache(void)
102 {
103 	/*
104 	 * Make sure all delayed rcu free inodes are flushed before we
105 	 * destroy cache.
106 	 */
107 	rcu_barrier();
108 	kmem_cache_destroy(minix_inode_cachep);
109 }
110 
111 static const struct super_operations minix_sops = {
112 	.alloc_inode	= minix_alloc_inode,
113 	.destroy_inode	= minix_destroy_inode,
114 	.write_inode	= minix_write_inode,
115 	.evict_inode	= minix_evict_inode,
116 	.put_super	= minix_put_super,
117 	.statfs		= minix_statfs,
118 	.remount_fs	= minix_remount,
119 };
120 
121 static int minix_remount (struct super_block * sb, int * flags, char * data)
122 {
123 	struct minix_sb_info * sbi = minix_sb(sb);
124 	struct minix_super_block * ms;
125 
126 	ms = sbi->s_ms;
127 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
128 		return 0;
129 	if (*flags & MS_RDONLY) {
130 		if (ms->s_state & MINIX_VALID_FS ||
131 		    !(sbi->s_mount_state & MINIX_VALID_FS))
132 			return 0;
133 		/* Mounting a rw partition read-only. */
134 		if (sbi->s_version != MINIX_V3)
135 			ms->s_state = sbi->s_mount_state;
136 		mark_buffer_dirty(sbi->s_sbh);
137 	} else {
138 	  	/* Mount a partition which is read-only, read-write. */
139 		if (sbi->s_version != MINIX_V3) {
140 			sbi->s_mount_state = ms->s_state;
141 			ms->s_state &= ~MINIX_VALID_FS;
142 		} else {
143 			sbi->s_mount_state = MINIX_VALID_FS;
144 		}
145 		mark_buffer_dirty(sbi->s_sbh);
146 
147 		if (!(sbi->s_mount_state & MINIX_VALID_FS))
148 			printk("MINIX-fs warning: remounting unchecked fs, "
149 				"running fsck is recommended\n");
150 		else if ((sbi->s_mount_state & MINIX_ERROR_FS))
151 			printk("MINIX-fs warning: remounting fs with errors, "
152 				"running fsck is recommended\n");
153 	}
154 	return 0;
155 }
156 
157 static int minix_fill_super(struct super_block *s, void *data, int silent)
158 {
159 	struct buffer_head *bh;
160 	struct buffer_head **map;
161 	struct minix_super_block *ms;
162 	struct minix3_super_block *m3s = NULL;
163 	unsigned long i, block;
164 	struct inode *root_inode;
165 	struct minix_sb_info *sbi;
166 	int ret = -EINVAL;
167 
168 	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
169 	if (!sbi)
170 		return -ENOMEM;
171 	s->s_fs_info = sbi;
172 
173 	BUILD_BUG_ON(32 != sizeof (struct minix_inode));
174 	BUILD_BUG_ON(64 != sizeof(struct minix2_inode));
175 
176 	if (!sb_set_blocksize(s, BLOCK_SIZE))
177 		goto out_bad_hblock;
178 
179 	if (!(bh = sb_bread(s, 1)))
180 		goto out_bad_sb;
181 
182 	ms = (struct minix_super_block *) bh->b_data;
183 	sbi->s_ms = ms;
184 	sbi->s_sbh = bh;
185 	sbi->s_mount_state = ms->s_state;
186 	sbi->s_ninodes = ms->s_ninodes;
187 	sbi->s_nzones = ms->s_nzones;
188 	sbi->s_imap_blocks = ms->s_imap_blocks;
189 	sbi->s_zmap_blocks = ms->s_zmap_blocks;
190 	sbi->s_firstdatazone = ms->s_firstdatazone;
191 	sbi->s_log_zone_size = ms->s_log_zone_size;
192 	sbi->s_max_size = ms->s_max_size;
193 	s->s_magic = ms->s_magic;
194 	if (s->s_magic == MINIX_SUPER_MAGIC) {
195 		sbi->s_version = MINIX_V1;
196 		sbi->s_dirsize = 16;
197 		sbi->s_namelen = 14;
198 		s->s_max_links = MINIX_LINK_MAX;
199 	} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
200 		sbi->s_version = MINIX_V1;
201 		sbi->s_dirsize = 32;
202 		sbi->s_namelen = 30;
203 		s->s_max_links = MINIX_LINK_MAX;
204 	} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
205 		sbi->s_version = MINIX_V2;
206 		sbi->s_nzones = ms->s_zones;
207 		sbi->s_dirsize = 16;
208 		sbi->s_namelen = 14;
209 		s->s_max_links = MINIX2_LINK_MAX;
210 	} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
211 		sbi->s_version = MINIX_V2;
212 		sbi->s_nzones = ms->s_zones;
213 		sbi->s_dirsize = 32;
214 		sbi->s_namelen = 30;
215 		s->s_max_links = MINIX2_LINK_MAX;
216 	} else if ( *(__u16 *)(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
217 		m3s = (struct minix3_super_block *) bh->b_data;
218 		s->s_magic = m3s->s_magic;
219 		sbi->s_imap_blocks = m3s->s_imap_blocks;
220 		sbi->s_zmap_blocks = m3s->s_zmap_blocks;
221 		sbi->s_firstdatazone = m3s->s_firstdatazone;
222 		sbi->s_log_zone_size = m3s->s_log_zone_size;
223 		sbi->s_max_size = m3s->s_max_size;
224 		sbi->s_ninodes = m3s->s_ninodes;
225 		sbi->s_nzones = m3s->s_zones;
226 		sbi->s_dirsize = 64;
227 		sbi->s_namelen = 60;
228 		sbi->s_version = MINIX_V3;
229 		sbi->s_mount_state = MINIX_VALID_FS;
230 		sb_set_blocksize(s, m3s->s_blocksize);
231 		s->s_max_links = MINIX2_LINK_MAX;
232 	} else
233 		goto out_no_fs;
234 
235 	/*
236 	 * Allocate the buffer map to keep the superblock small.
237 	 */
238 	if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
239 		goto out_illegal_sb;
240 	i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
241 	map = kzalloc(i, GFP_KERNEL);
242 	if (!map)
243 		goto out_no_map;
244 	sbi->s_imap = &map[0];
245 	sbi->s_zmap = &map[sbi->s_imap_blocks];
246 
247 	block=2;
248 	for (i=0 ; i < sbi->s_imap_blocks ; i++) {
249 		if (!(sbi->s_imap[i]=sb_bread(s, block)))
250 			goto out_no_bitmap;
251 		block++;
252 	}
253 	for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
254 		if (!(sbi->s_zmap[i]=sb_bread(s, block)))
255 			goto out_no_bitmap;
256 		block++;
257 	}
258 
259 	minix_set_bit(0,sbi->s_imap[0]->b_data);
260 	minix_set_bit(0,sbi->s_zmap[0]->b_data);
261 
262 	/* Apparently minix can create filesystems that allocate more blocks for
263 	 * the bitmaps than needed.  We simply ignore that, but verify it didn't
264 	 * create one with not enough blocks and bail out if so.
265 	 */
266 	block = minix_blocks_needed(sbi->s_ninodes, s->s_blocksize);
267 	if (sbi->s_imap_blocks < block) {
268 		printk("MINIX-fs: file system does not have enough "
269 				"imap blocks allocated.  Refusing to mount\n");
270 		goto out_no_bitmap;
271 	}
272 
273 	block = minix_blocks_needed(
274 			(sbi->s_nzones - (sbi->s_firstdatazone + 1)),
275 			s->s_blocksize);
276 	if (sbi->s_zmap_blocks < block) {
277 		printk("MINIX-fs: file system does not have enough "
278 				"zmap blocks allocated.  Refusing to mount.\n");
279 		goto out_no_bitmap;
280 	}
281 
282 	/* set up enough so that it can read an inode */
283 	s->s_op = &minix_sops;
284 	root_inode = minix_iget(s, MINIX_ROOT_INO);
285 	if (IS_ERR(root_inode)) {
286 		ret = PTR_ERR(root_inode);
287 		goto out_no_root;
288 	}
289 
290 	ret = -ENOMEM;
291 	s->s_root = d_make_root(root_inode);
292 	if (!s->s_root)
293 		goto out_no_root;
294 
295 	if (!(s->s_flags & MS_RDONLY)) {
296 		if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
297 			ms->s_state &= ~MINIX_VALID_FS;
298 		mark_buffer_dirty(bh);
299 	}
300 	if (!(sbi->s_mount_state & MINIX_VALID_FS))
301 		printk("MINIX-fs: mounting unchecked file system, "
302 			"running fsck is recommended\n");
303 	else if (sbi->s_mount_state & MINIX_ERROR_FS)
304 		printk("MINIX-fs: mounting file system with errors, "
305 			"running fsck is recommended\n");
306 
307 	return 0;
308 
309 out_no_root:
310 	if (!silent)
311 		printk("MINIX-fs: get root inode failed\n");
312 	goto out_freemap;
313 
314 out_no_bitmap:
315 	printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
316 out_freemap:
317 	for (i = 0; i < sbi->s_imap_blocks; i++)
318 		brelse(sbi->s_imap[i]);
319 	for (i = 0; i < sbi->s_zmap_blocks; i++)
320 		brelse(sbi->s_zmap[i]);
321 	kfree(sbi->s_imap);
322 	goto out_release;
323 
324 out_no_map:
325 	ret = -ENOMEM;
326 	if (!silent)
327 		printk("MINIX-fs: can't allocate map\n");
328 	goto out_release;
329 
330 out_illegal_sb:
331 	if (!silent)
332 		printk("MINIX-fs: bad superblock\n");
333 	goto out_release;
334 
335 out_no_fs:
336 	if (!silent)
337 		printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
338 		       "on device %s.\n", s->s_id);
339 out_release:
340 	brelse(bh);
341 	goto out;
342 
343 out_bad_hblock:
344 	printk("MINIX-fs: blocksize too small for device\n");
345 	goto out;
346 
347 out_bad_sb:
348 	printk("MINIX-fs: unable to read superblock\n");
349 out:
350 	s->s_fs_info = NULL;
351 	kfree(sbi);
352 	return ret;
353 }
354 
355 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
356 {
357 	struct super_block *sb = dentry->d_sb;
358 	struct minix_sb_info *sbi = minix_sb(sb);
359 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
360 	buf->f_type = sb->s_magic;
361 	buf->f_bsize = sb->s_blocksize;
362 	buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
363 	buf->f_bfree = minix_count_free_blocks(sb);
364 	buf->f_bavail = buf->f_bfree;
365 	buf->f_files = sbi->s_ninodes;
366 	buf->f_ffree = minix_count_free_inodes(sb);
367 	buf->f_namelen = sbi->s_namelen;
368 	buf->f_fsid.val[0] = (u32)id;
369 	buf->f_fsid.val[1] = (u32)(id >> 32);
370 
371 	return 0;
372 }
373 
374 static int minix_get_block(struct inode *inode, sector_t block,
375 		    struct buffer_head *bh_result, int create)
376 {
377 	if (INODE_VERSION(inode) == MINIX_V1)
378 		return V1_minix_get_block(inode, block, bh_result, create);
379 	else
380 		return V2_minix_get_block(inode, block, bh_result, create);
381 }
382 
383 static int minix_writepage(struct page *page, struct writeback_control *wbc)
384 {
385 	return block_write_full_page(page, minix_get_block, wbc);
386 }
387 
388 static int minix_readpage(struct file *file, struct page *page)
389 {
390 	return block_read_full_page(page,minix_get_block);
391 }
392 
393 int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
394 {
395 	return __block_write_begin(page, pos, len, minix_get_block);
396 }
397 
398 static int minix_write_begin(struct file *file, struct address_space *mapping,
399 			loff_t pos, unsigned len, unsigned flags,
400 			struct page **pagep, void **fsdata)
401 {
402 	int ret;
403 
404 	ret = block_write_begin(mapping, pos, len, flags, pagep,
405 				minix_get_block);
406 	if (unlikely(ret)) {
407 		loff_t isize = mapping->host->i_size;
408 		if (pos + len > isize)
409 			vmtruncate(mapping->host, isize);
410 	}
411 
412 	return ret;
413 }
414 
415 static sector_t minix_bmap(struct address_space *mapping, sector_t block)
416 {
417 	return generic_block_bmap(mapping,block,minix_get_block);
418 }
419 
420 static const struct address_space_operations minix_aops = {
421 	.readpage = minix_readpage,
422 	.writepage = minix_writepage,
423 	.write_begin = minix_write_begin,
424 	.write_end = generic_write_end,
425 	.bmap = minix_bmap
426 };
427 
428 static const struct inode_operations minix_symlink_inode_operations = {
429 	.readlink	= generic_readlink,
430 	.follow_link	= page_follow_link_light,
431 	.put_link	= page_put_link,
432 	.getattr	= minix_getattr,
433 };
434 
435 void minix_set_inode(struct inode *inode, dev_t rdev)
436 {
437 	if (S_ISREG(inode->i_mode)) {
438 		inode->i_op = &minix_file_inode_operations;
439 		inode->i_fop = &minix_file_operations;
440 		inode->i_mapping->a_ops = &minix_aops;
441 	} else if (S_ISDIR(inode->i_mode)) {
442 		inode->i_op = &minix_dir_inode_operations;
443 		inode->i_fop = &minix_dir_operations;
444 		inode->i_mapping->a_ops = &minix_aops;
445 	} else if (S_ISLNK(inode->i_mode)) {
446 		inode->i_op = &minix_symlink_inode_operations;
447 		inode->i_mapping->a_ops = &minix_aops;
448 	} else
449 		init_special_inode(inode, inode->i_mode, rdev);
450 }
451 
452 /*
453  * The minix V1 function to read an inode.
454  */
455 static struct inode *V1_minix_iget(struct inode *inode)
456 {
457 	struct buffer_head * bh;
458 	struct minix_inode * raw_inode;
459 	struct minix_inode_info *minix_inode = minix_i(inode);
460 	int i;
461 
462 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
463 	if (!raw_inode) {
464 		iget_failed(inode);
465 		return ERR_PTR(-EIO);
466 	}
467 	inode->i_mode = raw_inode->i_mode;
468 	i_uid_write(inode, raw_inode->i_uid);
469 	i_gid_write(inode, raw_inode->i_gid);
470 	set_nlink(inode, raw_inode->i_nlinks);
471 	inode->i_size = raw_inode->i_size;
472 	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = raw_inode->i_time;
473 	inode->i_mtime.tv_nsec = 0;
474 	inode->i_atime.tv_nsec = 0;
475 	inode->i_ctime.tv_nsec = 0;
476 	inode->i_blocks = 0;
477 	for (i = 0; i < 9; i++)
478 		minix_inode->u.i1_data[i] = raw_inode->i_zone[i];
479 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
480 	brelse(bh);
481 	unlock_new_inode(inode);
482 	return inode;
483 }
484 
485 /*
486  * The minix V2 function to read an inode.
487  */
488 static struct inode *V2_minix_iget(struct inode *inode)
489 {
490 	struct buffer_head * bh;
491 	struct minix2_inode * raw_inode;
492 	struct minix_inode_info *minix_inode = minix_i(inode);
493 	int i;
494 
495 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
496 	if (!raw_inode) {
497 		iget_failed(inode);
498 		return ERR_PTR(-EIO);
499 	}
500 	inode->i_mode = raw_inode->i_mode;
501 	i_uid_write(inode, raw_inode->i_uid);
502 	i_gid_write(inode, raw_inode->i_gid);
503 	set_nlink(inode, raw_inode->i_nlinks);
504 	inode->i_size = raw_inode->i_size;
505 	inode->i_mtime.tv_sec = raw_inode->i_mtime;
506 	inode->i_atime.tv_sec = raw_inode->i_atime;
507 	inode->i_ctime.tv_sec = raw_inode->i_ctime;
508 	inode->i_mtime.tv_nsec = 0;
509 	inode->i_atime.tv_nsec = 0;
510 	inode->i_ctime.tv_nsec = 0;
511 	inode->i_blocks = 0;
512 	for (i = 0; i < 10; i++)
513 		minix_inode->u.i2_data[i] = raw_inode->i_zone[i];
514 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
515 	brelse(bh);
516 	unlock_new_inode(inode);
517 	return inode;
518 }
519 
520 /*
521  * The global function to read an inode.
522  */
523 struct inode *minix_iget(struct super_block *sb, unsigned long ino)
524 {
525 	struct inode *inode;
526 
527 	inode = iget_locked(sb, ino);
528 	if (!inode)
529 		return ERR_PTR(-ENOMEM);
530 	if (!(inode->i_state & I_NEW))
531 		return inode;
532 
533 	if (INODE_VERSION(inode) == MINIX_V1)
534 		return V1_minix_iget(inode);
535 	else
536 		return V2_minix_iget(inode);
537 }
538 
539 /*
540  * The minix V1 function to synchronize an inode.
541  */
542 static struct buffer_head * V1_minix_update_inode(struct inode * inode)
543 {
544 	struct buffer_head * bh;
545 	struct minix_inode * raw_inode;
546 	struct minix_inode_info *minix_inode = minix_i(inode);
547 	int i;
548 
549 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
550 	if (!raw_inode)
551 		return NULL;
552 	raw_inode->i_mode = inode->i_mode;
553 	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
554 	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
555 	raw_inode->i_nlinks = inode->i_nlink;
556 	raw_inode->i_size = inode->i_size;
557 	raw_inode->i_time = inode->i_mtime.tv_sec;
558 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
559 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
560 	else for (i = 0; i < 9; i++)
561 		raw_inode->i_zone[i] = minix_inode->u.i1_data[i];
562 	mark_buffer_dirty(bh);
563 	return bh;
564 }
565 
566 /*
567  * The minix V2 function to synchronize an inode.
568  */
569 static struct buffer_head * V2_minix_update_inode(struct inode * inode)
570 {
571 	struct buffer_head * bh;
572 	struct minix2_inode * raw_inode;
573 	struct minix_inode_info *minix_inode = minix_i(inode);
574 	int i;
575 
576 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
577 	if (!raw_inode)
578 		return NULL;
579 	raw_inode->i_mode = inode->i_mode;
580 	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
581 	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
582 	raw_inode->i_nlinks = inode->i_nlink;
583 	raw_inode->i_size = inode->i_size;
584 	raw_inode->i_mtime = inode->i_mtime.tv_sec;
585 	raw_inode->i_atime = inode->i_atime.tv_sec;
586 	raw_inode->i_ctime = inode->i_ctime.tv_sec;
587 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
588 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
589 	else for (i = 0; i < 10; i++)
590 		raw_inode->i_zone[i] = minix_inode->u.i2_data[i];
591 	mark_buffer_dirty(bh);
592 	return bh;
593 }
594 
595 static int minix_write_inode(struct inode *inode, struct writeback_control *wbc)
596 {
597 	int err = 0;
598 	struct buffer_head *bh;
599 
600 	if (INODE_VERSION(inode) == MINIX_V1)
601 		bh = V1_minix_update_inode(inode);
602 	else
603 		bh = V2_minix_update_inode(inode);
604 	if (!bh)
605 		return -EIO;
606 	if (wbc->sync_mode == WB_SYNC_ALL && buffer_dirty(bh)) {
607 		sync_dirty_buffer(bh);
608 		if (buffer_req(bh) && !buffer_uptodate(bh)) {
609 			printk("IO error syncing minix inode [%s:%08lx]\n",
610 				inode->i_sb->s_id, inode->i_ino);
611 			err = -EIO;
612 		}
613 	}
614 	brelse (bh);
615 	return err;
616 }
617 
618 int minix_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
619 {
620 	struct super_block *sb = dentry->d_sb;
621 	generic_fillattr(dentry->d_inode, stat);
622 	if (INODE_VERSION(dentry->d_inode) == MINIX_V1)
623 		stat->blocks = (BLOCK_SIZE / 512) * V1_minix_blocks(stat->size, sb);
624 	else
625 		stat->blocks = (sb->s_blocksize / 512) * V2_minix_blocks(stat->size, sb);
626 	stat->blksize = sb->s_blocksize;
627 	return 0;
628 }
629 
630 /*
631  * The function that is called for file truncation.
632  */
633 void minix_truncate(struct inode * inode)
634 {
635 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
636 		return;
637 	if (INODE_VERSION(inode) == MINIX_V1)
638 		V1_minix_truncate(inode);
639 	else
640 		V2_minix_truncate(inode);
641 }
642 
643 static struct dentry *minix_mount(struct file_system_type *fs_type,
644 	int flags, const char *dev_name, void *data)
645 {
646 	return mount_bdev(fs_type, flags, dev_name, data, minix_fill_super);
647 }
648 
649 static struct file_system_type minix_fs_type = {
650 	.owner		= THIS_MODULE,
651 	.name		= "minix",
652 	.mount		= minix_mount,
653 	.kill_sb	= kill_block_super,
654 	.fs_flags	= FS_REQUIRES_DEV,
655 };
656 
657 static int __init init_minix_fs(void)
658 {
659 	int err = init_inodecache();
660 	if (err)
661 		goto out1;
662 	err = register_filesystem(&minix_fs_type);
663 	if (err)
664 		goto out;
665 	return 0;
666 out:
667 	destroy_inodecache();
668 out1:
669 	return err;
670 }
671 
672 static void __exit exit_minix_fs(void)
673 {
674         unregister_filesystem(&minix_fs_type);
675 	destroy_inodecache();
676 }
677 
678 module_init(init_minix_fs)
679 module_exit(exit_minix_fs)
680 MODULE_LICENSE("GPL");
681 
682