xref: /linux/fs/minix/inode.c (revision 02bf6cc72cc2a6258411ddf1649f33a65fc9a06e)
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 	if (!(sb->s_flags & MS_RDONLY)) {
39 		if (sbi->s_version != MINIX_V3)	 /* s_state is now out from V3 sb */
40 			sbi->s_ms->s_state = sbi->s_mount_state;
41 		mark_buffer_dirty(sbi->s_sbh);
42 	}
43 	for (i = 0; i < sbi->s_imap_blocks; i++)
44 		brelse(sbi->s_imap[i]);
45 	for (i = 0; i < sbi->s_zmap_blocks; i++)
46 		brelse(sbi->s_zmap[i]);
47 	brelse (sbi->s_sbh);
48 	kfree(sbi->s_imap);
49 	sb->s_fs_info = NULL;
50 	kfree(sbi);
51 }
52 
53 static struct kmem_cache * minix_inode_cachep;
54 
55 static struct inode *minix_alloc_inode(struct super_block *sb)
56 {
57 	struct minix_inode_info *ei;
58 	ei = (struct minix_inode_info *)kmem_cache_alloc(minix_inode_cachep, GFP_KERNEL);
59 	if (!ei)
60 		return NULL;
61 	return &ei->vfs_inode;
62 }
63 
64 static void minix_destroy_inode(struct inode *inode)
65 {
66 	kmem_cache_free(minix_inode_cachep, minix_i(inode));
67 }
68 
69 static void init_once(void *foo)
70 {
71 	struct minix_inode_info *ei = (struct minix_inode_info *) foo;
72 
73 	inode_init_once(&ei->vfs_inode);
74 }
75 
76 static int init_inodecache(void)
77 {
78 	minix_inode_cachep = kmem_cache_create("minix_inode_cache",
79 					     sizeof(struct minix_inode_info),
80 					     0, (SLAB_RECLAIM_ACCOUNT|
81 						SLAB_MEM_SPREAD),
82 					     init_once);
83 	if (minix_inode_cachep == NULL)
84 		return -ENOMEM;
85 	return 0;
86 }
87 
88 static void destroy_inodecache(void)
89 {
90 	kmem_cache_destroy(minix_inode_cachep);
91 }
92 
93 static const struct super_operations minix_sops = {
94 	.alloc_inode	= minix_alloc_inode,
95 	.destroy_inode	= minix_destroy_inode,
96 	.write_inode	= minix_write_inode,
97 	.delete_inode	= minix_delete_inode,
98 	.put_super	= minix_put_super,
99 	.statfs		= minix_statfs,
100 	.remount_fs	= minix_remount,
101 };
102 
103 static int minix_remount (struct super_block * sb, int * flags, char * data)
104 {
105 	struct minix_sb_info * sbi = minix_sb(sb);
106 	struct minix_super_block * ms;
107 
108 	ms = sbi->s_ms;
109 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
110 		return 0;
111 	if (*flags & MS_RDONLY) {
112 		if (ms->s_state & MINIX_VALID_FS ||
113 		    !(sbi->s_mount_state & MINIX_VALID_FS))
114 			return 0;
115 		/* Mounting a rw partition read-only. */
116 		if (sbi->s_version != MINIX_V3)
117 			ms->s_state = sbi->s_mount_state;
118 		mark_buffer_dirty(sbi->s_sbh);
119 	} else {
120 	  	/* Mount a partition which is read-only, read-write. */
121 		if (sbi->s_version != MINIX_V3) {
122 			sbi->s_mount_state = ms->s_state;
123 			ms->s_state &= ~MINIX_VALID_FS;
124 		} else {
125 			sbi->s_mount_state = MINIX_VALID_FS;
126 		}
127 		mark_buffer_dirty(sbi->s_sbh);
128 
129 		if (!(sbi->s_mount_state & MINIX_VALID_FS))
130 			printk("MINIX-fs warning: remounting unchecked fs, "
131 				"running fsck is recommended\n");
132 		else if ((sbi->s_mount_state & MINIX_ERROR_FS))
133 			printk("MINIX-fs warning: remounting fs with errors, "
134 				"running fsck is recommended\n");
135 	}
136 	return 0;
137 }
138 
139 static int minix_fill_super(struct super_block *s, void *data, int silent)
140 {
141 	struct buffer_head *bh;
142 	struct buffer_head **map;
143 	struct minix_super_block *ms;
144 	struct minix3_super_block *m3s = NULL;
145 	unsigned long i, block;
146 	struct inode *root_inode;
147 	struct minix_sb_info *sbi;
148 	int ret = -EINVAL;
149 
150 	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
151 	if (!sbi)
152 		return -ENOMEM;
153 	s->s_fs_info = sbi;
154 
155 	BUILD_BUG_ON(32 != sizeof (struct minix_inode));
156 	BUILD_BUG_ON(64 != sizeof(struct minix2_inode));
157 
158 	if (!sb_set_blocksize(s, BLOCK_SIZE))
159 		goto out_bad_hblock;
160 
161 	if (!(bh = sb_bread(s, 1)))
162 		goto out_bad_sb;
163 
164 	ms = (struct minix_super_block *) bh->b_data;
165 	sbi->s_ms = ms;
166 	sbi->s_sbh = bh;
167 	sbi->s_mount_state = ms->s_state;
168 	sbi->s_ninodes = ms->s_ninodes;
169 	sbi->s_nzones = ms->s_nzones;
170 	sbi->s_imap_blocks = ms->s_imap_blocks;
171 	sbi->s_zmap_blocks = ms->s_zmap_blocks;
172 	sbi->s_firstdatazone = ms->s_firstdatazone;
173 	sbi->s_log_zone_size = ms->s_log_zone_size;
174 	sbi->s_max_size = ms->s_max_size;
175 	s->s_magic = ms->s_magic;
176 	if (s->s_magic == MINIX_SUPER_MAGIC) {
177 		sbi->s_version = MINIX_V1;
178 		sbi->s_dirsize = 16;
179 		sbi->s_namelen = 14;
180 		sbi->s_link_max = MINIX_LINK_MAX;
181 	} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
182 		sbi->s_version = MINIX_V1;
183 		sbi->s_dirsize = 32;
184 		sbi->s_namelen = 30;
185 		sbi->s_link_max = MINIX_LINK_MAX;
186 	} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
187 		sbi->s_version = MINIX_V2;
188 		sbi->s_nzones = ms->s_zones;
189 		sbi->s_dirsize = 16;
190 		sbi->s_namelen = 14;
191 		sbi->s_link_max = MINIX2_LINK_MAX;
192 	} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
193 		sbi->s_version = MINIX_V2;
194 		sbi->s_nzones = ms->s_zones;
195 		sbi->s_dirsize = 32;
196 		sbi->s_namelen = 30;
197 		sbi->s_link_max = MINIX2_LINK_MAX;
198 	} else if ( *(__u16 *)(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
199 		m3s = (struct minix3_super_block *) bh->b_data;
200 		s->s_magic = m3s->s_magic;
201 		sbi->s_imap_blocks = m3s->s_imap_blocks;
202 		sbi->s_zmap_blocks = m3s->s_zmap_blocks;
203 		sbi->s_firstdatazone = m3s->s_firstdatazone;
204 		sbi->s_log_zone_size = m3s->s_log_zone_size;
205 		sbi->s_max_size = m3s->s_max_size;
206 		sbi->s_ninodes = m3s->s_ninodes;
207 		sbi->s_nzones = m3s->s_zones;
208 		sbi->s_dirsize = 64;
209 		sbi->s_namelen = 60;
210 		sbi->s_version = MINIX_V3;
211 		sbi->s_link_max = MINIX2_LINK_MAX;
212 		sbi->s_mount_state = MINIX_VALID_FS;
213 		sb_set_blocksize(s, m3s->s_blocksize);
214 	} else
215 		goto out_no_fs;
216 
217 	/*
218 	 * Allocate the buffer map to keep the superblock small.
219 	 */
220 	if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
221 		goto out_illegal_sb;
222 	i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
223 	map = kzalloc(i, GFP_KERNEL);
224 	if (!map)
225 		goto out_no_map;
226 	sbi->s_imap = &map[0];
227 	sbi->s_zmap = &map[sbi->s_imap_blocks];
228 
229 	block=2;
230 	for (i=0 ; i < sbi->s_imap_blocks ; i++) {
231 		if (!(sbi->s_imap[i]=sb_bread(s, block)))
232 			goto out_no_bitmap;
233 		block++;
234 	}
235 	for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
236 		if (!(sbi->s_zmap[i]=sb_bread(s, block)))
237 			goto out_no_bitmap;
238 		block++;
239 	}
240 
241 	minix_set_bit(0,sbi->s_imap[0]->b_data);
242 	minix_set_bit(0,sbi->s_zmap[0]->b_data);
243 
244 	/* set up enough so that it can read an inode */
245 	s->s_op = &minix_sops;
246 	root_inode = minix_iget(s, MINIX_ROOT_INO);
247 	if (IS_ERR(root_inode)) {
248 		ret = PTR_ERR(root_inode);
249 		goto out_no_root;
250 	}
251 
252 	ret = -ENOMEM;
253 	s->s_root = d_alloc_root(root_inode);
254 	if (!s->s_root)
255 		goto out_iput;
256 
257 	if (!(s->s_flags & MS_RDONLY)) {
258 		if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
259 			ms->s_state &= ~MINIX_VALID_FS;
260 		mark_buffer_dirty(bh);
261 	}
262 	if (!(sbi->s_mount_state & MINIX_VALID_FS))
263 		printk("MINIX-fs: mounting unchecked file system, "
264 			"running fsck is recommended\n");
265  	else if (sbi->s_mount_state & MINIX_ERROR_FS)
266 		printk("MINIX-fs: mounting file system with errors, "
267 			"running fsck is recommended\n");
268 	return 0;
269 
270 out_iput:
271 	iput(root_inode);
272 	goto out_freemap;
273 
274 out_no_root:
275 	if (!silent)
276 		printk("MINIX-fs: get root inode failed\n");
277 	goto out_freemap;
278 
279 out_no_bitmap:
280 	printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
281 out_freemap:
282 	for (i = 0; i < sbi->s_imap_blocks; i++)
283 		brelse(sbi->s_imap[i]);
284 	for (i = 0; i < sbi->s_zmap_blocks; i++)
285 		brelse(sbi->s_zmap[i]);
286 	kfree(sbi->s_imap);
287 	goto out_release;
288 
289 out_no_map:
290 	ret = -ENOMEM;
291 	if (!silent)
292 		printk("MINIX-fs: can't allocate map\n");
293 	goto out_release;
294 
295 out_illegal_sb:
296 	if (!silent)
297 		printk("MINIX-fs: bad superblock\n");
298 	goto out_release;
299 
300 out_no_fs:
301 	if (!silent)
302 		printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
303 		       "on device %s.\n", s->s_id);
304 out_release:
305 	brelse(bh);
306 	goto out;
307 
308 out_bad_hblock:
309 	printk("MINIX-fs: blocksize too small for device\n");
310 	goto out;
311 
312 out_bad_sb:
313 	printk("MINIX-fs: unable to read superblock\n");
314 out:
315 	s->s_fs_info = NULL;
316 	kfree(sbi);
317 	return ret;
318 }
319 
320 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
321 {
322 	struct super_block *sb = dentry->d_sb;
323 	struct minix_sb_info *sbi = minix_sb(sb);
324 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
325 	buf->f_type = sb->s_magic;
326 	buf->f_bsize = sb->s_blocksize;
327 	buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
328 	buf->f_bfree = minix_count_free_blocks(sbi);
329 	buf->f_bavail = buf->f_bfree;
330 	buf->f_files = sbi->s_ninodes;
331 	buf->f_ffree = minix_count_free_inodes(sbi);
332 	buf->f_namelen = sbi->s_namelen;
333 	buf->f_fsid.val[0] = (u32)id;
334 	buf->f_fsid.val[1] = (u32)(id >> 32);
335 
336 	return 0;
337 }
338 
339 static int minix_get_block(struct inode *inode, sector_t block,
340 		    struct buffer_head *bh_result, int create)
341 {
342 	if (INODE_VERSION(inode) == MINIX_V1)
343 		return V1_minix_get_block(inode, block, bh_result, create);
344 	else
345 		return V2_minix_get_block(inode, block, bh_result, create);
346 }
347 
348 static int minix_writepage(struct page *page, struct writeback_control *wbc)
349 {
350 	return block_write_full_page(page, minix_get_block, wbc);
351 }
352 
353 static int minix_readpage(struct file *file, struct page *page)
354 {
355 	return block_read_full_page(page,minix_get_block);
356 }
357 
358 int __minix_write_begin(struct file *file, struct address_space *mapping,
359 			loff_t pos, unsigned len, unsigned flags,
360 			struct page **pagep, void **fsdata)
361 {
362 	return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
363 				minix_get_block);
364 }
365 
366 static int minix_write_begin(struct file *file, struct address_space *mapping,
367 			loff_t pos, unsigned len, unsigned flags,
368 			struct page **pagep, void **fsdata)
369 {
370 	*pagep = NULL;
371 	return __minix_write_begin(file, mapping, pos, len, flags, pagep, fsdata);
372 }
373 
374 static sector_t minix_bmap(struct address_space *mapping, sector_t block)
375 {
376 	return generic_block_bmap(mapping,block,minix_get_block);
377 }
378 
379 static const struct address_space_operations minix_aops = {
380 	.readpage = minix_readpage,
381 	.writepage = minix_writepage,
382 	.sync_page = block_sync_page,
383 	.write_begin = minix_write_begin,
384 	.write_end = generic_write_end,
385 	.bmap = minix_bmap
386 };
387 
388 static const struct inode_operations minix_symlink_inode_operations = {
389 	.readlink	= generic_readlink,
390 	.follow_link	= page_follow_link_light,
391 	.put_link	= page_put_link,
392 	.getattr	= minix_getattr,
393 };
394 
395 void minix_set_inode(struct inode *inode, dev_t rdev)
396 {
397 	if (S_ISREG(inode->i_mode)) {
398 		inode->i_op = &minix_file_inode_operations;
399 		inode->i_fop = &minix_file_operations;
400 		inode->i_mapping->a_ops = &minix_aops;
401 	} else if (S_ISDIR(inode->i_mode)) {
402 		inode->i_op = &minix_dir_inode_operations;
403 		inode->i_fop = &minix_dir_operations;
404 		inode->i_mapping->a_ops = &minix_aops;
405 	} else if (S_ISLNK(inode->i_mode)) {
406 		inode->i_op = &minix_symlink_inode_operations;
407 		inode->i_mapping->a_ops = &minix_aops;
408 	} else
409 		init_special_inode(inode, inode->i_mode, rdev);
410 }
411 
412 /*
413  * The minix V1 function to read an inode.
414  */
415 static struct inode *V1_minix_iget(struct inode *inode)
416 {
417 	struct buffer_head * bh;
418 	struct minix_inode * raw_inode;
419 	struct minix_inode_info *minix_inode = minix_i(inode);
420 	int i;
421 
422 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
423 	if (!raw_inode) {
424 		iget_failed(inode);
425 		return ERR_PTR(-EIO);
426 	}
427 	inode->i_mode = raw_inode->i_mode;
428 	inode->i_uid = (uid_t)raw_inode->i_uid;
429 	inode->i_gid = (gid_t)raw_inode->i_gid;
430 	inode->i_nlink = raw_inode->i_nlinks;
431 	inode->i_size = raw_inode->i_size;
432 	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = raw_inode->i_time;
433 	inode->i_mtime.tv_nsec = 0;
434 	inode->i_atime.tv_nsec = 0;
435 	inode->i_ctime.tv_nsec = 0;
436 	inode->i_blocks = 0;
437 	for (i = 0; i < 9; i++)
438 		minix_inode->u.i1_data[i] = raw_inode->i_zone[i];
439 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
440 	brelse(bh);
441 	unlock_new_inode(inode);
442 	return inode;
443 }
444 
445 /*
446  * The minix V2 function to read an inode.
447  */
448 static struct inode *V2_minix_iget(struct inode *inode)
449 {
450 	struct buffer_head * bh;
451 	struct minix2_inode * raw_inode;
452 	struct minix_inode_info *minix_inode = minix_i(inode);
453 	int i;
454 
455 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
456 	if (!raw_inode) {
457 		iget_failed(inode);
458 		return ERR_PTR(-EIO);
459 	}
460 	inode->i_mode = raw_inode->i_mode;
461 	inode->i_uid = (uid_t)raw_inode->i_uid;
462 	inode->i_gid = (gid_t)raw_inode->i_gid;
463 	inode->i_nlink = raw_inode->i_nlinks;
464 	inode->i_size = raw_inode->i_size;
465 	inode->i_mtime.tv_sec = raw_inode->i_mtime;
466 	inode->i_atime.tv_sec = raw_inode->i_atime;
467 	inode->i_ctime.tv_sec = raw_inode->i_ctime;
468 	inode->i_mtime.tv_nsec = 0;
469 	inode->i_atime.tv_nsec = 0;
470 	inode->i_ctime.tv_nsec = 0;
471 	inode->i_blocks = 0;
472 	for (i = 0; i < 10; i++)
473 		minix_inode->u.i2_data[i] = raw_inode->i_zone[i];
474 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
475 	brelse(bh);
476 	unlock_new_inode(inode);
477 	return inode;
478 }
479 
480 /*
481  * The global function to read an inode.
482  */
483 struct inode *minix_iget(struct super_block *sb, unsigned long ino)
484 {
485 	struct inode *inode;
486 
487 	inode = iget_locked(sb, ino);
488 	if (!inode)
489 		return ERR_PTR(-ENOMEM);
490 	if (!(inode->i_state & I_NEW))
491 		return inode;
492 
493 	if (INODE_VERSION(inode) == MINIX_V1)
494 		return V1_minix_iget(inode);
495 	else
496 		return V2_minix_iget(inode);
497 }
498 
499 /*
500  * The minix V1 function to synchronize an inode.
501  */
502 static struct buffer_head * V1_minix_update_inode(struct inode * inode)
503 {
504 	struct buffer_head * bh;
505 	struct minix_inode * raw_inode;
506 	struct minix_inode_info *minix_inode = minix_i(inode);
507 	int i;
508 
509 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
510 	if (!raw_inode)
511 		return NULL;
512 	raw_inode->i_mode = inode->i_mode;
513 	raw_inode->i_uid = fs_high2lowuid(inode->i_uid);
514 	raw_inode->i_gid = fs_high2lowgid(inode->i_gid);
515 	raw_inode->i_nlinks = inode->i_nlink;
516 	raw_inode->i_size = inode->i_size;
517 	raw_inode->i_time = inode->i_mtime.tv_sec;
518 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
519 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
520 	else for (i = 0; i < 9; i++)
521 		raw_inode->i_zone[i] = minix_inode->u.i1_data[i];
522 	mark_buffer_dirty(bh);
523 	return bh;
524 }
525 
526 /*
527  * The minix V2 function to synchronize an inode.
528  */
529 static struct buffer_head * V2_minix_update_inode(struct inode * inode)
530 {
531 	struct buffer_head * bh;
532 	struct minix2_inode * raw_inode;
533 	struct minix_inode_info *minix_inode = minix_i(inode);
534 	int i;
535 
536 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
537 	if (!raw_inode)
538 		return NULL;
539 	raw_inode->i_mode = inode->i_mode;
540 	raw_inode->i_uid = fs_high2lowuid(inode->i_uid);
541 	raw_inode->i_gid = fs_high2lowgid(inode->i_gid);
542 	raw_inode->i_nlinks = inode->i_nlink;
543 	raw_inode->i_size = inode->i_size;
544 	raw_inode->i_mtime = inode->i_mtime.tv_sec;
545 	raw_inode->i_atime = inode->i_atime.tv_sec;
546 	raw_inode->i_ctime = inode->i_ctime.tv_sec;
547 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
548 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
549 	else for (i = 0; i < 10; i++)
550 		raw_inode->i_zone[i] = minix_inode->u.i2_data[i];
551 	mark_buffer_dirty(bh);
552 	return bh;
553 }
554 
555 static int minix_write_inode(struct inode *inode, int wait)
556 {
557 	int err = 0;
558 	struct buffer_head *bh;
559 
560 	if (INODE_VERSION(inode) == MINIX_V1)
561 		bh = V1_minix_update_inode(inode);
562 	else
563 		bh = V2_minix_update_inode(inode);
564 	if (!bh)
565 		return -EIO;
566 	if (wait && buffer_dirty(bh)) {
567 		sync_dirty_buffer(bh);
568 		if (buffer_req(bh) && !buffer_uptodate(bh)) {
569 			printk("IO error syncing minix inode [%s:%08lx]\n",
570 				inode->i_sb->s_id, inode->i_ino);
571 			err = -EIO;
572 		}
573 	}
574 	brelse (bh);
575 	return err;
576 }
577 
578 int minix_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
579 {
580 	struct inode *dir = dentry->d_parent->d_inode;
581 	struct super_block *sb = dir->i_sb;
582 	generic_fillattr(dentry->d_inode, stat);
583 	if (INODE_VERSION(dentry->d_inode) == MINIX_V1)
584 		stat->blocks = (BLOCK_SIZE / 512) * V1_minix_blocks(stat->size, sb);
585 	else
586 		stat->blocks = (sb->s_blocksize / 512) * V2_minix_blocks(stat->size, sb);
587 	stat->blksize = sb->s_blocksize;
588 	return 0;
589 }
590 
591 /*
592  * The function that is called for file truncation.
593  */
594 void minix_truncate(struct inode * inode)
595 {
596 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
597 		return;
598 	if (INODE_VERSION(inode) == MINIX_V1)
599 		V1_minix_truncate(inode);
600 	else
601 		V2_minix_truncate(inode);
602 }
603 
604 static int minix_get_sb(struct file_system_type *fs_type,
605 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
606 {
607 	return get_sb_bdev(fs_type, flags, dev_name, data, minix_fill_super,
608 			   mnt);
609 }
610 
611 static struct file_system_type minix_fs_type = {
612 	.owner		= THIS_MODULE,
613 	.name		= "minix",
614 	.get_sb		= minix_get_sb,
615 	.kill_sb	= kill_block_super,
616 	.fs_flags	= FS_REQUIRES_DEV,
617 };
618 
619 static int __init init_minix_fs(void)
620 {
621 	int err = init_inodecache();
622 	if (err)
623 		goto out1;
624 	err = register_filesystem(&minix_fs_type);
625 	if (err)
626 		goto out;
627 	return 0;
628 out:
629 	destroy_inodecache();
630 out1:
631 	return err;
632 }
633 
634 static void __exit exit_minix_fs(void)
635 {
636         unregister_filesystem(&minix_fs_type);
637 	destroy_inodecache();
638 }
639 
640 module_init(init_minix_fs)
641 module_exit(exit_minix_fs)
642 MODULE_LICENSE("GPL");
643 
644