xref: /openbmc/linux/fs/minix/inode.c (revision 6e1db88d536adcbbfe562b2d4b7d6425784fff12)
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_delete_inode(struct inode *inode)
28 {
29 	truncate_inode_pages(&inode->i_data, 0);
30 	inode->i_size = 0;
31 	minix_truncate(inode);
32 	minix_free_inode(inode);
33 }
34 
35 static void minix_put_super(struct super_block *sb)
36 {
37 	int i;
38 	struct minix_sb_info *sbi = minix_sb(sb);
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 
55 static struct kmem_cache * minix_inode_cachep;
56 
57 static struct inode *minix_alloc_inode(struct super_block *sb)
58 {
59 	struct minix_inode_info *ei;
60 	ei = (struct minix_inode_info *)kmem_cache_alloc(minix_inode_cachep, GFP_KERNEL);
61 	if (!ei)
62 		return NULL;
63 	return &ei->vfs_inode;
64 }
65 
66 static void minix_destroy_inode(struct inode *inode)
67 {
68 	kmem_cache_free(minix_inode_cachep, minix_i(inode));
69 }
70 
71 static void init_once(void *foo)
72 {
73 	struct minix_inode_info *ei = (struct minix_inode_info *) foo;
74 
75 	inode_init_once(&ei->vfs_inode);
76 }
77 
78 static int init_inodecache(void)
79 {
80 	minix_inode_cachep = kmem_cache_create("minix_inode_cache",
81 					     sizeof(struct minix_inode_info),
82 					     0, (SLAB_RECLAIM_ACCOUNT|
83 						SLAB_MEM_SPREAD),
84 					     init_once);
85 	if (minix_inode_cachep == NULL)
86 		return -ENOMEM;
87 	return 0;
88 }
89 
90 static void destroy_inodecache(void)
91 {
92 	kmem_cache_destroy(minix_inode_cachep);
93 }
94 
95 static const struct super_operations minix_sops = {
96 	.alloc_inode	= minix_alloc_inode,
97 	.destroy_inode	= minix_destroy_inode,
98 	.write_inode	= minix_write_inode,
99 	.delete_inode	= minix_delete_inode,
100 	.put_super	= minix_put_super,
101 	.statfs		= minix_statfs,
102 	.remount_fs	= minix_remount,
103 };
104 
105 static int minix_remount (struct super_block * sb, int * flags, char * data)
106 {
107 	struct minix_sb_info * sbi = minix_sb(sb);
108 	struct minix_super_block * ms;
109 
110 	ms = sbi->s_ms;
111 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
112 		return 0;
113 	if (*flags & MS_RDONLY) {
114 		if (ms->s_state & MINIX_VALID_FS ||
115 		    !(sbi->s_mount_state & MINIX_VALID_FS))
116 			return 0;
117 		/* Mounting a rw partition read-only. */
118 		if (sbi->s_version != MINIX_V3)
119 			ms->s_state = sbi->s_mount_state;
120 		mark_buffer_dirty(sbi->s_sbh);
121 	} else {
122 	  	/* Mount a partition which is read-only, read-write. */
123 		if (sbi->s_version != MINIX_V3) {
124 			sbi->s_mount_state = ms->s_state;
125 			ms->s_state &= ~MINIX_VALID_FS;
126 		} else {
127 			sbi->s_mount_state = MINIX_VALID_FS;
128 		}
129 		mark_buffer_dirty(sbi->s_sbh);
130 
131 		if (!(sbi->s_mount_state & MINIX_VALID_FS))
132 			printk("MINIX-fs warning: remounting unchecked fs, "
133 				"running fsck is recommended\n");
134 		else if ((sbi->s_mount_state & MINIX_ERROR_FS))
135 			printk("MINIX-fs warning: remounting fs with errors, "
136 				"running fsck is recommended\n");
137 	}
138 	return 0;
139 }
140 
141 static int minix_fill_super(struct super_block *s, void *data, int silent)
142 {
143 	struct buffer_head *bh;
144 	struct buffer_head **map;
145 	struct minix_super_block *ms;
146 	struct minix3_super_block *m3s = NULL;
147 	unsigned long i, block;
148 	struct inode *root_inode;
149 	struct minix_sb_info *sbi;
150 	int ret = -EINVAL;
151 
152 	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
153 	if (!sbi)
154 		return -ENOMEM;
155 	s->s_fs_info = sbi;
156 
157 	BUILD_BUG_ON(32 != sizeof (struct minix_inode));
158 	BUILD_BUG_ON(64 != sizeof(struct minix2_inode));
159 
160 	if (!sb_set_blocksize(s, BLOCK_SIZE))
161 		goto out_bad_hblock;
162 
163 	if (!(bh = sb_bread(s, 1)))
164 		goto out_bad_sb;
165 
166 	ms = (struct minix_super_block *) bh->b_data;
167 	sbi->s_ms = ms;
168 	sbi->s_sbh = bh;
169 	sbi->s_mount_state = ms->s_state;
170 	sbi->s_ninodes = ms->s_ninodes;
171 	sbi->s_nzones = ms->s_nzones;
172 	sbi->s_imap_blocks = ms->s_imap_blocks;
173 	sbi->s_zmap_blocks = ms->s_zmap_blocks;
174 	sbi->s_firstdatazone = ms->s_firstdatazone;
175 	sbi->s_log_zone_size = ms->s_log_zone_size;
176 	sbi->s_max_size = ms->s_max_size;
177 	s->s_magic = ms->s_magic;
178 	if (s->s_magic == MINIX_SUPER_MAGIC) {
179 		sbi->s_version = MINIX_V1;
180 		sbi->s_dirsize = 16;
181 		sbi->s_namelen = 14;
182 		sbi->s_link_max = MINIX_LINK_MAX;
183 	} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
184 		sbi->s_version = MINIX_V1;
185 		sbi->s_dirsize = 32;
186 		sbi->s_namelen = 30;
187 		sbi->s_link_max = MINIX_LINK_MAX;
188 	} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
189 		sbi->s_version = MINIX_V2;
190 		sbi->s_nzones = ms->s_zones;
191 		sbi->s_dirsize = 16;
192 		sbi->s_namelen = 14;
193 		sbi->s_link_max = MINIX2_LINK_MAX;
194 	} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
195 		sbi->s_version = MINIX_V2;
196 		sbi->s_nzones = ms->s_zones;
197 		sbi->s_dirsize = 32;
198 		sbi->s_namelen = 30;
199 		sbi->s_link_max = MINIX2_LINK_MAX;
200 	} else if ( *(__u16 *)(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
201 		m3s = (struct minix3_super_block *) bh->b_data;
202 		s->s_magic = m3s->s_magic;
203 		sbi->s_imap_blocks = m3s->s_imap_blocks;
204 		sbi->s_zmap_blocks = m3s->s_zmap_blocks;
205 		sbi->s_firstdatazone = m3s->s_firstdatazone;
206 		sbi->s_log_zone_size = m3s->s_log_zone_size;
207 		sbi->s_max_size = m3s->s_max_size;
208 		sbi->s_ninodes = m3s->s_ninodes;
209 		sbi->s_nzones = m3s->s_zones;
210 		sbi->s_dirsize = 64;
211 		sbi->s_namelen = 60;
212 		sbi->s_version = MINIX_V3;
213 		sbi->s_link_max = MINIX2_LINK_MAX;
214 		sbi->s_mount_state = MINIX_VALID_FS;
215 		sb_set_blocksize(s, m3s->s_blocksize);
216 	} else
217 		goto out_no_fs;
218 
219 	/*
220 	 * Allocate the buffer map to keep the superblock small.
221 	 */
222 	if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
223 		goto out_illegal_sb;
224 	i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
225 	map = kzalloc(i, GFP_KERNEL);
226 	if (!map)
227 		goto out_no_map;
228 	sbi->s_imap = &map[0];
229 	sbi->s_zmap = &map[sbi->s_imap_blocks];
230 
231 	block=2;
232 	for (i=0 ; i < sbi->s_imap_blocks ; i++) {
233 		if (!(sbi->s_imap[i]=sb_bread(s, block)))
234 			goto out_no_bitmap;
235 		block++;
236 	}
237 	for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
238 		if (!(sbi->s_zmap[i]=sb_bread(s, block)))
239 			goto out_no_bitmap;
240 		block++;
241 	}
242 
243 	minix_set_bit(0,sbi->s_imap[0]->b_data);
244 	minix_set_bit(0,sbi->s_zmap[0]->b_data);
245 
246 	/* set up enough so that it can read an inode */
247 	s->s_op = &minix_sops;
248 	root_inode = minix_iget(s, MINIX_ROOT_INO);
249 	if (IS_ERR(root_inode)) {
250 		ret = PTR_ERR(root_inode);
251 		goto out_no_root;
252 	}
253 
254 	ret = -ENOMEM;
255 	s->s_root = d_alloc_root(root_inode);
256 	if (!s->s_root)
257 		goto out_iput;
258 
259 	if (!(s->s_flags & MS_RDONLY)) {
260 		if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
261 			ms->s_state &= ~MINIX_VALID_FS;
262 		mark_buffer_dirty(bh);
263 	}
264 	if (!(sbi->s_mount_state & MINIX_VALID_FS))
265 		printk("MINIX-fs: mounting unchecked file system, "
266 			"running fsck is recommended\n");
267  	else if (sbi->s_mount_state & MINIX_ERROR_FS)
268 		printk("MINIX-fs: mounting file system with errors, "
269 			"running fsck is recommended\n");
270 	return 0;
271 
272 out_iput:
273 	iput(root_inode);
274 	goto out_freemap;
275 
276 out_no_root:
277 	if (!silent)
278 		printk("MINIX-fs: get root inode failed\n");
279 	goto out_freemap;
280 
281 out_no_bitmap:
282 	printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
283 out_freemap:
284 	for (i = 0; i < sbi->s_imap_blocks; i++)
285 		brelse(sbi->s_imap[i]);
286 	for (i = 0; i < sbi->s_zmap_blocks; i++)
287 		brelse(sbi->s_zmap[i]);
288 	kfree(sbi->s_imap);
289 	goto out_release;
290 
291 out_no_map:
292 	ret = -ENOMEM;
293 	if (!silent)
294 		printk("MINIX-fs: can't allocate map\n");
295 	goto out_release;
296 
297 out_illegal_sb:
298 	if (!silent)
299 		printk("MINIX-fs: bad superblock\n");
300 	goto out_release;
301 
302 out_no_fs:
303 	if (!silent)
304 		printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
305 		       "on device %s.\n", s->s_id);
306 out_release:
307 	brelse(bh);
308 	goto out;
309 
310 out_bad_hblock:
311 	printk("MINIX-fs: blocksize too small for device\n");
312 	goto out;
313 
314 out_bad_sb:
315 	printk("MINIX-fs: unable to read superblock\n");
316 out:
317 	s->s_fs_info = NULL;
318 	kfree(sbi);
319 	return ret;
320 }
321 
322 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
323 {
324 	struct super_block *sb = dentry->d_sb;
325 	struct minix_sb_info *sbi = minix_sb(sb);
326 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
327 	buf->f_type = sb->s_magic;
328 	buf->f_bsize = sb->s_blocksize;
329 	buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
330 	buf->f_bfree = minix_count_free_blocks(sbi);
331 	buf->f_bavail = buf->f_bfree;
332 	buf->f_files = sbi->s_ninodes;
333 	buf->f_ffree = minix_count_free_inodes(sbi);
334 	buf->f_namelen = sbi->s_namelen;
335 	buf->f_fsid.val[0] = (u32)id;
336 	buf->f_fsid.val[1] = (u32)(id >> 32);
337 
338 	return 0;
339 }
340 
341 static int minix_get_block(struct inode *inode, sector_t block,
342 		    struct buffer_head *bh_result, int create)
343 {
344 	if (INODE_VERSION(inode) == MINIX_V1)
345 		return V1_minix_get_block(inode, block, bh_result, create);
346 	else
347 		return V2_minix_get_block(inode, block, bh_result, create);
348 }
349 
350 static int minix_writepage(struct page *page, struct writeback_control *wbc)
351 {
352 	return block_write_full_page(page, minix_get_block, wbc);
353 }
354 
355 static int minix_readpage(struct file *file, struct page *page)
356 {
357 	return block_read_full_page(page,minix_get_block);
358 }
359 
360 int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
361 {
362 	return __block_write_begin(page, pos, len, minix_get_block);
363 }
364 
365 static int minix_write_begin(struct file *file, struct address_space *mapping,
366 			loff_t pos, unsigned len, unsigned flags,
367 			struct page **pagep, void **fsdata)
368 {
369 	*pagep = NULL;
370 	return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
371 				minix_get_block);
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, struct writeback_control *wbc)
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 (wbc->sync_mode == WB_SYNC_ALL && 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