xref: /linux/fs/minix/inode.c (revision e27ecdd94d81e5bc3d1f68591701db5adb342f0d)
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 
21 static int minix_write_inode(struct inode * inode, int wait);
22 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf);
23 static int minix_remount (struct super_block * sb, int * flags, char * data);
24 
25 static void minix_delete_inode(struct inode *inode)
26 {
27 	truncate_inode_pages(&inode->i_data, 0);
28 	inode->i_size = 0;
29 	minix_truncate(inode);
30 	minix_free_inode(inode);
31 }
32 
33 static void minix_put_super(struct super_block *sb)
34 {
35 	int i;
36 	struct minix_sb_info *sbi = minix_sb(sb);
37 
38 	lock_kernel();
39 
40 	if (!(sb->s_flags & MS_RDONLY)) {
41 		if (sbi->s_version != MINIX_V3)	 /* s_state is now out from V3 sb */
42 			sbi->s_ms->s_state = sbi->s_mount_state;
43 		mark_buffer_dirty(sbi->s_sbh);
44 	}
45 	for (i = 0; i < sbi->s_imap_blocks; i++)
46 		brelse(sbi->s_imap[i]);
47 	for (i = 0; i < sbi->s_zmap_blocks; i++)
48 		brelse(sbi->s_zmap[i]);
49 	brelse (sbi->s_sbh);
50 	kfree(sbi->s_imap);
51 	sb->s_fs_info = NULL;
52 	kfree(sbi);
53 
54 	unlock_kernel();
55 }
56 
57 static struct kmem_cache * minix_inode_cachep;
58 
59 static struct inode *minix_alloc_inode(struct super_block *sb)
60 {
61 	struct minix_inode_info *ei;
62 	ei = (struct minix_inode_info *)kmem_cache_alloc(minix_inode_cachep, GFP_KERNEL);
63 	if (!ei)
64 		return NULL;
65 	return &ei->vfs_inode;
66 }
67 
68 static void minix_destroy_inode(struct inode *inode)
69 {
70 	kmem_cache_free(minix_inode_cachep, minix_i(inode));
71 }
72 
73 static void init_once(void *foo)
74 {
75 	struct minix_inode_info *ei = (struct minix_inode_info *) foo;
76 
77 	inode_init_once(&ei->vfs_inode);
78 }
79 
80 static int init_inodecache(void)
81 {
82 	minix_inode_cachep = kmem_cache_create("minix_inode_cache",
83 					     sizeof(struct minix_inode_info),
84 					     0, (SLAB_RECLAIM_ACCOUNT|
85 						SLAB_MEM_SPREAD),
86 					     init_once);
87 	if (minix_inode_cachep == NULL)
88 		return -ENOMEM;
89 	return 0;
90 }
91 
92 static void destroy_inodecache(void)
93 {
94 	kmem_cache_destroy(minix_inode_cachep);
95 }
96 
97 static const struct super_operations minix_sops = {
98 	.alloc_inode	= minix_alloc_inode,
99 	.destroy_inode	= minix_destroy_inode,
100 	.write_inode	= minix_write_inode,
101 	.delete_inode	= minix_delete_inode,
102 	.put_super	= minix_put_super,
103 	.statfs		= minix_statfs,
104 	.remount_fs	= minix_remount,
105 };
106 
107 static int minix_remount (struct super_block * sb, int * flags, char * data)
108 {
109 	struct minix_sb_info * sbi = minix_sb(sb);
110 	struct minix_super_block * ms;
111 
112 	ms = sbi->s_ms;
113 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
114 		return 0;
115 	if (*flags & MS_RDONLY) {
116 		if (ms->s_state & MINIX_VALID_FS ||
117 		    !(sbi->s_mount_state & MINIX_VALID_FS))
118 			return 0;
119 		/* Mounting a rw partition read-only. */
120 		if (sbi->s_version != MINIX_V3)
121 			ms->s_state = sbi->s_mount_state;
122 		mark_buffer_dirty(sbi->s_sbh);
123 	} else {
124 	  	/* Mount a partition which is read-only, read-write. */
125 		if (sbi->s_version != MINIX_V3) {
126 			sbi->s_mount_state = ms->s_state;
127 			ms->s_state &= ~MINIX_VALID_FS;
128 		} else {
129 			sbi->s_mount_state = MINIX_VALID_FS;
130 		}
131 		mark_buffer_dirty(sbi->s_sbh);
132 
133 		if (!(sbi->s_mount_state & MINIX_VALID_FS))
134 			printk("MINIX-fs warning: remounting unchecked fs, "
135 				"running fsck is recommended\n");
136 		else if ((sbi->s_mount_state & MINIX_ERROR_FS))
137 			printk("MINIX-fs warning: remounting fs with errors, "
138 				"running fsck is recommended\n");
139 	}
140 	return 0;
141 }
142 
143 static int minix_fill_super(struct super_block *s, void *data, int silent)
144 {
145 	struct buffer_head *bh;
146 	struct buffer_head **map;
147 	struct minix_super_block *ms;
148 	struct minix3_super_block *m3s = NULL;
149 	unsigned long i, block;
150 	struct inode *root_inode;
151 	struct minix_sb_info *sbi;
152 	int ret = -EINVAL;
153 
154 	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
155 	if (!sbi)
156 		return -ENOMEM;
157 	s->s_fs_info = sbi;
158 
159 	BUILD_BUG_ON(32 != sizeof (struct minix_inode));
160 	BUILD_BUG_ON(64 != sizeof(struct minix2_inode));
161 
162 	if (!sb_set_blocksize(s, BLOCK_SIZE))
163 		goto out_bad_hblock;
164 
165 	if (!(bh = sb_bread(s, 1)))
166 		goto out_bad_sb;
167 
168 	ms = (struct minix_super_block *) bh->b_data;
169 	sbi->s_ms = ms;
170 	sbi->s_sbh = bh;
171 	sbi->s_mount_state = ms->s_state;
172 	sbi->s_ninodes = ms->s_ninodes;
173 	sbi->s_nzones = ms->s_nzones;
174 	sbi->s_imap_blocks = ms->s_imap_blocks;
175 	sbi->s_zmap_blocks = ms->s_zmap_blocks;
176 	sbi->s_firstdatazone = ms->s_firstdatazone;
177 	sbi->s_log_zone_size = ms->s_log_zone_size;
178 	sbi->s_max_size = ms->s_max_size;
179 	s->s_magic = ms->s_magic;
180 	if (s->s_magic == MINIX_SUPER_MAGIC) {
181 		sbi->s_version = MINIX_V1;
182 		sbi->s_dirsize = 16;
183 		sbi->s_namelen = 14;
184 		sbi->s_link_max = MINIX_LINK_MAX;
185 	} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
186 		sbi->s_version = MINIX_V1;
187 		sbi->s_dirsize = 32;
188 		sbi->s_namelen = 30;
189 		sbi->s_link_max = MINIX_LINK_MAX;
190 	} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
191 		sbi->s_version = MINIX_V2;
192 		sbi->s_nzones = ms->s_zones;
193 		sbi->s_dirsize = 16;
194 		sbi->s_namelen = 14;
195 		sbi->s_link_max = MINIX2_LINK_MAX;
196 	} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
197 		sbi->s_version = MINIX_V2;
198 		sbi->s_nzones = ms->s_zones;
199 		sbi->s_dirsize = 32;
200 		sbi->s_namelen = 30;
201 		sbi->s_link_max = MINIX2_LINK_MAX;
202 	} else if ( *(__u16 *)(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
203 		m3s = (struct minix3_super_block *) bh->b_data;
204 		s->s_magic = m3s->s_magic;
205 		sbi->s_imap_blocks = m3s->s_imap_blocks;
206 		sbi->s_zmap_blocks = m3s->s_zmap_blocks;
207 		sbi->s_firstdatazone = m3s->s_firstdatazone;
208 		sbi->s_log_zone_size = m3s->s_log_zone_size;
209 		sbi->s_max_size = m3s->s_max_size;
210 		sbi->s_ninodes = m3s->s_ninodes;
211 		sbi->s_nzones = m3s->s_zones;
212 		sbi->s_dirsize = 64;
213 		sbi->s_namelen = 60;
214 		sbi->s_version = MINIX_V3;
215 		sbi->s_link_max = MINIX2_LINK_MAX;
216 		sbi->s_mount_state = MINIX_VALID_FS;
217 		sb_set_blocksize(s, m3s->s_blocksize);
218 	} else
219 		goto out_no_fs;
220 
221 	/*
222 	 * Allocate the buffer map to keep the superblock small.
223 	 */
224 	if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
225 		goto out_illegal_sb;
226 	i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
227 	map = kzalloc(i, GFP_KERNEL);
228 	if (!map)
229 		goto out_no_map;
230 	sbi->s_imap = &map[0];
231 	sbi->s_zmap = &map[sbi->s_imap_blocks];
232 
233 	block=2;
234 	for (i=0 ; i < sbi->s_imap_blocks ; i++) {
235 		if (!(sbi->s_imap[i]=sb_bread(s, block)))
236 			goto out_no_bitmap;
237 		block++;
238 	}
239 	for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
240 		if (!(sbi->s_zmap[i]=sb_bread(s, block)))
241 			goto out_no_bitmap;
242 		block++;
243 	}
244 
245 	minix_set_bit(0,sbi->s_imap[0]->b_data);
246 	minix_set_bit(0,sbi->s_zmap[0]->b_data);
247 
248 	/* set up enough so that it can read an inode */
249 	s->s_op = &minix_sops;
250 	root_inode = minix_iget(s, MINIX_ROOT_INO);
251 	if (IS_ERR(root_inode)) {
252 		ret = PTR_ERR(root_inode);
253 		goto out_no_root;
254 	}
255 
256 	ret = -ENOMEM;
257 	s->s_root = d_alloc_root(root_inode);
258 	if (!s->s_root)
259 		goto out_iput;
260 
261 	if (!(s->s_flags & MS_RDONLY)) {
262 		if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
263 			ms->s_state &= ~MINIX_VALID_FS;
264 		mark_buffer_dirty(bh);
265 	}
266 	if (!(sbi->s_mount_state & MINIX_VALID_FS))
267 		printk("MINIX-fs: mounting unchecked file system, "
268 			"running fsck is recommended\n");
269  	else if (sbi->s_mount_state & MINIX_ERROR_FS)
270 		printk("MINIX-fs: mounting file system with errors, "
271 			"running fsck is recommended\n");
272 	return 0;
273 
274 out_iput:
275 	iput(root_inode);
276 	goto out_freemap;
277 
278 out_no_root:
279 	if (!silent)
280 		printk("MINIX-fs: get root inode failed\n");
281 	goto out_freemap;
282 
283 out_no_bitmap:
284 	printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
285 out_freemap:
286 	for (i = 0; i < sbi->s_imap_blocks; i++)
287 		brelse(sbi->s_imap[i]);
288 	for (i = 0; i < sbi->s_zmap_blocks; i++)
289 		brelse(sbi->s_zmap[i]);
290 	kfree(sbi->s_imap);
291 	goto out_release;
292 
293 out_no_map:
294 	ret = -ENOMEM;
295 	if (!silent)
296 		printk("MINIX-fs: can't allocate map\n");
297 	goto out_release;
298 
299 out_illegal_sb:
300 	if (!silent)
301 		printk("MINIX-fs: bad superblock\n");
302 	goto out_release;
303 
304 out_no_fs:
305 	if (!silent)
306 		printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
307 		       "on device %s.\n", s->s_id);
308 out_release:
309 	brelse(bh);
310 	goto out;
311 
312 out_bad_hblock:
313 	printk("MINIX-fs: blocksize too small for device\n");
314 	goto out;
315 
316 out_bad_sb:
317 	printk("MINIX-fs: unable to read superblock\n");
318 out:
319 	s->s_fs_info = NULL;
320 	kfree(sbi);
321 	return ret;
322 }
323 
324 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
325 {
326 	struct super_block *sb = dentry->d_sb;
327 	struct minix_sb_info *sbi = minix_sb(sb);
328 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
329 	buf->f_type = sb->s_magic;
330 	buf->f_bsize = sb->s_blocksize;
331 	buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
332 	buf->f_bfree = minix_count_free_blocks(sbi);
333 	buf->f_bavail = buf->f_bfree;
334 	buf->f_files = sbi->s_ninodes;
335 	buf->f_ffree = minix_count_free_inodes(sbi);
336 	buf->f_namelen = sbi->s_namelen;
337 	buf->f_fsid.val[0] = (u32)id;
338 	buf->f_fsid.val[1] = (u32)(id >> 32);
339 
340 	return 0;
341 }
342 
343 static int minix_get_block(struct inode *inode, sector_t block,
344 		    struct buffer_head *bh_result, int create)
345 {
346 	if (INODE_VERSION(inode) == MINIX_V1)
347 		return V1_minix_get_block(inode, block, bh_result, create);
348 	else
349 		return V2_minix_get_block(inode, block, bh_result, create);
350 }
351 
352 static int minix_writepage(struct page *page, struct writeback_control *wbc)
353 {
354 	return block_write_full_page(page, minix_get_block, wbc);
355 }
356 
357 static int minix_readpage(struct file *file, struct page *page)
358 {
359 	return block_read_full_page(page,minix_get_block);
360 }
361 
362 int __minix_write_begin(struct file *file, struct address_space *mapping,
363 			loff_t pos, unsigned len, unsigned flags,
364 			struct page **pagep, void **fsdata)
365 {
366 	return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
367 				minix_get_block);
368 }
369 
370 static int minix_write_begin(struct file *file, struct address_space *mapping,
371 			loff_t pos, unsigned len, unsigned flags,
372 			struct page **pagep, void **fsdata)
373 {
374 	*pagep = NULL;
375 	return __minix_write_begin(file, mapping, pos, len, flags, pagep, fsdata);
376 }
377 
378 static sector_t minix_bmap(struct address_space *mapping, sector_t block)
379 {
380 	return generic_block_bmap(mapping,block,minix_get_block);
381 }
382 
383 static const struct address_space_operations minix_aops = {
384 	.readpage = minix_readpage,
385 	.writepage = minix_writepage,
386 	.sync_page = block_sync_page,
387 	.write_begin = minix_write_begin,
388 	.write_end = generic_write_end,
389 	.bmap = minix_bmap
390 };
391 
392 static const struct inode_operations minix_symlink_inode_operations = {
393 	.readlink	= generic_readlink,
394 	.follow_link	= page_follow_link_light,
395 	.put_link	= page_put_link,
396 	.getattr	= minix_getattr,
397 };
398 
399 void minix_set_inode(struct inode *inode, dev_t rdev)
400 {
401 	if (S_ISREG(inode->i_mode)) {
402 		inode->i_op = &minix_file_inode_operations;
403 		inode->i_fop = &minix_file_operations;
404 		inode->i_mapping->a_ops = &minix_aops;
405 	} else if (S_ISDIR(inode->i_mode)) {
406 		inode->i_op = &minix_dir_inode_operations;
407 		inode->i_fop = &minix_dir_operations;
408 		inode->i_mapping->a_ops = &minix_aops;
409 	} else if (S_ISLNK(inode->i_mode)) {
410 		inode->i_op = &minix_symlink_inode_operations;
411 		inode->i_mapping->a_ops = &minix_aops;
412 	} else
413 		init_special_inode(inode, inode->i_mode, rdev);
414 }
415 
416 /*
417  * The minix V1 function to read an inode.
418  */
419 static struct inode *V1_minix_iget(struct inode *inode)
420 {
421 	struct buffer_head * bh;
422 	struct minix_inode * raw_inode;
423 	struct minix_inode_info *minix_inode = minix_i(inode);
424 	int i;
425 
426 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
427 	if (!raw_inode) {
428 		iget_failed(inode);
429 		return ERR_PTR(-EIO);
430 	}
431 	inode->i_mode = raw_inode->i_mode;
432 	inode->i_uid = (uid_t)raw_inode->i_uid;
433 	inode->i_gid = (gid_t)raw_inode->i_gid;
434 	inode->i_nlink = raw_inode->i_nlinks;
435 	inode->i_size = raw_inode->i_size;
436 	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = raw_inode->i_time;
437 	inode->i_mtime.tv_nsec = 0;
438 	inode->i_atime.tv_nsec = 0;
439 	inode->i_ctime.tv_nsec = 0;
440 	inode->i_blocks = 0;
441 	for (i = 0; i < 9; i++)
442 		minix_inode->u.i1_data[i] = raw_inode->i_zone[i];
443 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
444 	brelse(bh);
445 	unlock_new_inode(inode);
446 	return inode;
447 }
448 
449 /*
450  * The minix V2 function to read an inode.
451  */
452 static struct inode *V2_minix_iget(struct inode *inode)
453 {
454 	struct buffer_head * bh;
455 	struct minix2_inode * raw_inode;
456 	struct minix_inode_info *minix_inode = minix_i(inode);
457 	int i;
458 
459 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
460 	if (!raw_inode) {
461 		iget_failed(inode);
462 		return ERR_PTR(-EIO);
463 	}
464 	inode->i_mode = raw_inode->i_mode;
465 	inode->i_uid = (uid_t)raw_inode->i_uid;
466 	inode->i_gid = (gid_t)raw_inode->i_gid;
467 	inode->i_nlink = raw_inode->i_nlinks;
468 	inode->i_size = raw_inode->i_size;
469 	inode->i_mtime.tv_sec = raw_inode->i_mtime;
470 	inode->i_atime.tv_sec = raw_inode->i_atime;
471 	inode->i_ctime.tv_sec = raw_inode->i_ctime;
472 	inode->i_mtime.tv_nsec = 0;
473 	inode->i_atime.tv_nsec = 0;
474 	inode->i_ctime.tv_nsec = 0;
475 	inode->i_blocks = 0;
476 	for (i = 0; i < 10; i++)
477 		minix_inode->u.i2_data[i] = raw_inode->i_zone[i];
478 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
479 	brelse(bh);
480 	unlock_new_inode(inode);
481 	return inode;
482 }
483 
484 /*
485  * The global function to read an inode.
486  */
487 struct inode *minix_iget(struct super_block *sb, unsigned long ino)
488 {
489 	struct inode *inode;
490 
491 	inode = iget_locked(sb, ino);
492 	if (!inode)
493 		return ERR_PTR(-ENOMEM);
494 	if (!(inode->i_state & I_NEW))
495 		return inode;
496 
497 	if (INODE_VERSION(inode) == MINIX_V1)
498 		return V1_minix_iget(inode);
499 	else
500 		return V2_minix_iget(inode);
501 }
502 
503 /*
504  * The minix V1 function to synchronize an inode.
505  */
506 static struct buffer_head * V1_minix_update_inode(struct inode * inode)
507 {
508 	struct buffer_head * bh;
509 	struct minix_inode * raw_inode;
510 	struct minix_inode_info *minix_inode = minix_i(inode);
511 	int i;
512 
513 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
514 	if (!raw_inode)
515 		return NULL;
516 	raw_inode->i_mode = inode->i_mode;
517 	raw_inode->i_uid = fs_high2lowuid(inode->i_uid);
518 	raw_inode->i_gid = fs_high2lowgid(inode->i_gid);
519 	raw_inode->i_nlinks = inode->i_nlink;
520 	raw_inode->i_size = inode->i_size;
521 	raw_inode->i_time = inode->i_mtime.tv_sec;
522 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
523 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
524 	else for (i = 0; i < 9; i++)
525 		raw_inode->i_zone[i] = minix_inode->u.i1_data[i];
526 	mark_buffer_dirty(bh);
527 	return bh;
528 }
529 
530 /*
531  * The minix V2 function to synchronize an inode.
532  */
533 static struct buffer_head * V2_minix_update_inode(struct inode * inode)
534 {
535 	struct buffer_head * bh;
536 	struct minix2_inode * raw_inode;
537 	struct minix_inode_info *minix_inode = minix_i(inode);
538 	int i;
539 
540 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
541 	if (!raw_inode)
542 		return NULL;
543 	raw_inode->i_mode = inode->i_mode;
544 	raw_inode->i_uid = fs_high2lowuid(inode->i_uid);
545 	raw_inode->i_gid = fs_high2lowgid(inode->i_gid);
546 	raw_inode->i_nlinks = inode->i_nlink;
547 	raw_inode->i_size = inode->i_size;
548 	raw_inode->i_mtime = inode->i_mtime.tv_sec;
549 	raw_inode->i_atime = inode->i_atime.tv_sec;
550 	raw_inode->i_ctime = inode->i_ctime.tv_sec;
551 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
552 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
553 	else for (i = 0; i < 10; i++)
554 		raw_inode->i_zone[i] = minix_inode->u.i2_data[i];
555 	mark_buffer_dirty(bh);
556 	return bh;
557 }
558 
559 static int minix_write_inode(struct inode *inode, int wait)
560 {
561 	int err = 0;
562 	struct buffer_head *bh;
563 
564 	if (INODE_VERSION(inode) == MINIX_V1)
565 		bh = V1_minix_update_inode(inode);
566 	else
567 		bh = V2_minix_update_inode(inode);
568 	if (!bh)
569 		return -EIO;
570 	if (wait && buffer_dirty(bh)) {
571 		sync_dirty_buffer(bh);
572 		if (buffer_req(bh) && !buffer_uptodate(bh)) {
573 			printk("IO error syncing minix inode [%s:%08lx]\n",
574 				inode->i_sb->s_id, inode->i_ino);
575 			err = -EIO;
576 		}
577 	}
578 	brelse (bh);
579 	return err;
580 }
581 
582 int minix_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
583 {
584 	struct inode *dir = dentry->d_parent->d_inode;
585 	struct super_block *sb = dir->i_sb;
586 	generic_fillattr(dentry->d_inode, stat);
587 	if (INODE_VERSION(dentry->d_inode) == MINIX_V1)
588 		stat->blocks = (BLOCK_SIZE / 512) * V1_minix_blocks(stat->size, sb);
589 	else
590 		stat->blocks = (sb->s_blocksize / 512) * V2_minix_blocks(stat->size, sb);
591 	stat->blksize = sb->s_blocksize;
592 	return 0;
593 }
594 
595 /*
596  * The function that is called for file truncation.
597  */
598 void minix_truncate(struct inode * inode)
599 {
600 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
601 		return;
602 	if (INODE_VERSION(inode) == MINIX_V1)
603 		V1_minix_truncate(inode);
604 	else
605 		V2_minix_truncate(inode);
606 }
607 
608 static int minix_get_sb(struct file_system_type *fs_type,
609 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
610 {
611 	return get_sb_bdev(fs_type, flags, dev_name, data, minix_fill_super,
612 			   mnt);
613 }
614 
615 static struct file_system_type minix_fs_type = {
616 	.owner		= THIS_MODULE,
617 	.name		= "minix",
618 	.get_sb		= minix_get_sb,
619 	.kill_sb	= kill_block_super,
620 	.fs_flags	= FS_REQUIRES_DEV,
621 };
622 
623 static int __init init_minix_fs(void)
624 {
625 	int err = init_inodecache();
626 	if (err)
627 		goto out1;
628 	err = register_filesystem(&minix_fs_type);
629 	if (err)
630 		goto out;
631 	return 0;
632 out:
633 	destroy_inodecache();
634 out1:
635 	return err;
636 }
637 
638 static void __exit exit_minix_fs(void)
639 {
640         unregister_filesystem(&minix_fs_type);
641 	destroy_inodecache();
642 }
643 
644 module_init(init_minix_fs)
645 module_exit(exit_minix_fs)
646 MODULE_LICENSE("GPL");
647 
648