xref: /openbmc/linux/fs/minix/inode.c (revision fb574682)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/fs/minix/inode.c
4  *
5  *  Copyright (C) 1991, 1992  Linus Torvalds
6  *
7  *  Copyright (C) 1996  Gertjan van Wingerde
8  *	Minix V2 fs support.
9  *
10  *  Modified for 680x0 by Andreas Schwab
11  *  Updated to filesystem version 3 by Daniel Aragones
12  */
13 
14 #include <linux/module.h>
15 #include "minix.h"
16 #include <linux/buffer_head.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19 #include <linux/highuid.h>
20 #include <linux/vfs.h>
21 #include <linux/writeback.h>
22 
23 static int minix_write_inode(struct inode *inode,
24 		struct writeback_control *wbc);
25 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf);
26 static int minix_remount (struct super_block * sb, int * flags, char * data);
27 
28 static void minix_evict_inode(struct inode *inode)
29 {
30 	truncate_inode_pages_final(&inode->i_data);
31 	if (!inode->i_nlink) {
32 		inode->i_size = 0;
33 		minix_truncate(inode);
34 	}
35 	invalidate_inode_buffers(inode);
36 	clear_inode(inode);
37 	if (!inode->i_nlink)
38 		minix_free_inode(inode);
39 }
40 
41 static void minix_put_super(struct super_block *sb)
42 {
43 	int i;
44 	struct minix_sb_info *sbi = minix_sb(sb);
45 
46 	if (!sb_rdonly(sb)) {
47 		if (sbi->s_version != MINIX_V3)	 /* s_state is now out from V3 sb */
48 			sbi->s_ms->s_state = sbi->s_mount_state;
49 		mark_buffer_dirty(sbi->s_sbh);
50 	}
51 	for (i = 0; i < sbi->s_imap_blocks; i++)
52 		brelse(sbi->s_imap[i]);
53 	for (i = 0; i < sbi->s_zmap_blocks; i++)
54 		brelse(sbi->s_zmap[i]);
55 	brelse (sbi->s_sbh);
56 	kfree(sbi->s_imap);
57 	sb->s_fs_info = NULL;
58 	kfree(sbi);
59 }
60 
61 static struct kmem_cache * minix_inode_cachep;
62 
63 static struct inode *minix_alloc_inode(struct super_block *sb)
64 {
65 	struct minix_inode_info *ei;
66 	ei = kmem_cache_alloc(minix_inode_cachep, GFP_KERNEL);
67 	if (!ei)
68 		return NULL;
69 	return &ei->vfs_inode;
70 }
71 
72 static void minix_free_in_core_inode(struct inode *inode)
73 {
74 	kmem_cache_free(minix_inode_cachep, minix_i(inode));
75 }
76 
77 static void init_once(void *foo)
78 {
79 	struct minix_inode_info *ei = (struct minix_inode_info *) foo;
80 
81 	inode_init_once(&ei->vfs_inode);
82 }
83 
84 static int __init init_inodecache(void)
85 {
86 	minix_inode_cachep = kmem_cache_create("minix_inode_cache",
87 					     sizeof(struct minix_inode_info),
88 					     0, (SLAB_RECLAIM_ACCOUNT|
89 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
90 					     init_once);
91 	if (minix_inode_cachep == NULL)
92 		return -ENOMEM;
93 	return 0;
94 }
95 
96 static void destroy_inodecache(void)
97 {
98 	/*
99 	 * Make sure all delayed rcu free inodes are flushed before we
100 	 * destroy cache.
101 	 */
102 	rcu_barrier();
103 	kmem_cache_destroy(minix_inode_cachep);
104 }
105 
106 static const struct super_operations minix_sops = {
107 	.alloc_inode	= minix_alloc_inode,
108 	.free_inode	= minix_free_in_core_inode,
109 	.write_inode	= minix_write_inode,
110 	.evict_inode	= minix_evict_inode,
111 	.put_super	= minix_put_super,
112 	.statfs		= minix_statfs,
113 	.remount_fs	= minix_remount,
114 };
115 
116 static int minix_remount (struct super_block * sb, int * flags, char * data)
117 {
118 	struct minix_sb_info * sbi = minix_sb(sb);
119 	struct minix_super_block * ms;
120 
121 	sync_filesystem(sb);
122 	ms = sbi->s_ms;
123 	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
124 		return 0;
125 	if (*flags & SB_RDONLY) {
126 		if (ms->s_state & MINIX_VALID_FS ||
127 		    !(sbi->s_mount_state & MINIX_VALID_FS))
128 			return 0;
129 		/* Mounting a rw partition read-only. */
130 		if (sbi->s_version != MINIX_V3)
131 			ms->s_state = sbi->s_mount_state;
132 		mark_buffer_dirty(sbi->s_sbh);
133 	} else {
134 	  	/* Mount a partition which is read-only, read-write. */
135 		if (sbi->s_version != MINIX_V3) {
136 			sbi->s_mount_state = ms->s_state;
137 			ms->s_state &= ~MINIX_VALID_FS;
138 		} else {
139 			sbi->s_mount_state = MINIX_VALID_FS;
140 		}
141 		mark_buffer_dirty(sbi->s_sbh);
142 
143 		if (!(sbi->s_mount_state & MINIX_VALID_FS))
144 			printk("MINIX-fs warning: remounting unchecked fs, "
145 				"running fsck is recommended\n");
146 		else if ((sbi->s_mount_state & MINIX_ERROR_FS))
147 			printk("MINIX-fs warning: remounting fs with errors, "
148 				"running fsck is recommended\n");
149 	}
150 	return 0;
151 }
152 
153 static int minix_fill_super(struct super_block *s, void *data, int silent)
154 {
155 	struct buffer_head *bh;
156 	struct buffer_head **map;
157 	struct minix_super_block *ms;
158 	struct minix3_super_block *m3s = NULL;
159 	unsigned long i, block;
160 	struct inode *root_inode;
161 	struct minix_sb_info *sbi;
162 	int ret = -EINVAL;
163 
164 	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
165 	if (!sbi)
166 		return -ENOMEM;
167 	s->s_fs_info = sbi;
168 
169 	BUILD_BUG_ON(32 != sizeof (struct minix_inode));
170 	BUILD_BUG_ON(64 != sizeof(struct minix2_inode));
171 
172 	if (!sb_set_blocksize(s, BLOCK_SIZE))
173 		goto out_bad_hblock;
174 
175 	if (!(bh = sb_bread(s, 1)))
176 		goto out_bad_sb;
177 
178 	ms = (struct minix_super_block *) bh->b_data;
179 	sbi->s_ms = ms;
180 	sbi->s_sbh = bh;
181 	sbi->s_mount_state = ms->s_state;
182 	sbi->s_ninodes = ms->s_ninodes;
183 	sbi->s_nzones = ms->s_nzones;
184 	sbi->s_imap_blocks = ms->s_imap_blocks;
185 	sbi->s_zmap_blocks = ms->s_zmap_blocks;
186 	sbi->s_firstdatazone = ms->s_firstdatazone;
187 	sbi->s_log_zone_size = ms->s_log_zone_size;
188 	sbi->s_max_size = ms->s_max_size;
189 	s->s_magic = ms->s_magic;
190 	if (s->s_magic == MINIX_SUPER_MAGIC) {
191 		sbi->s_version = MINIX_V1;
192 		sbi->s_dirsize = 16;
193 		sbi->s_namelen = 14;
194 		s->s_max_links = MINIX_LINK_MAX;
195 	} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
196 		sbi->s_version = MINIX_V1;
197 		sbi->s_dirsize = 32;
198 		sbi->s_namelen = 30;
199 		s->s_max_links = MINIX_LINK_MAX;
200 	} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
201 		sbi->s_version = MINIX_V2;
202 		sbi->s_nzones = ms->s_zones;
203 		sbi->s_dirsize = 16;
204 		sbi->s_namelen = 14;
205 		s->s_max_links = MINIX2_LINK_MAX;
206 	} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
207 		sbi->s_version = MINIX_V2;
208 		sbi->s_nzones = ms->s_zones;
209 		sbi->s_dirsize = 32;
210 		sbi->s_namelen = 30;
211 		s->s_max_links = MINIX2_LINK_MAX;
212 	} else if ( *(__u16 *)(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
213 		m3s = (struct minix3_super_block *) bh->b_data;
214 		s->s_magic = m3s->s_magic;
215 		sbi->s_imap_blocks = m3s->s_imap_blocks;
216 		sbi->s_zmap_blocks = m3s->s_zmap_blocks;
217 		sbi->s_firstdatazone = m3s->s_firstdatazone;
218 		sbi->s_log_zone_size = m3s->s_log_zone_size;
219 		sbi->s_max_size = m3s->s_max_size;
220 		sbi->s_ninodes = m3s->s_ninodes;
221 		sbi->s_nzones = m3s->s_zones;
222 		sbi->s_dirsize = 64;
223 		sbi->s_namelen = 60;
224 		sbi->s_version = MINIX_V3;
225 		sbi->s_mount_state = MINIX_VALID_FS;
226 		sb_set_blocksize(s, m3s->s_blocksize);
227 		s->s_max_links = MINIX2_LINK_MAX;
228 	} else
229 		goto out_no_fs;
230 
231 	/*
232 	 * Allocate the buffer map to keep the superblock small.
233 	 */
234 	if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
235 		goto out_illegal_sb;
236 	i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
237 	map = kzalloc(i, GFP_KERNEL);
238 	if (!map)
239 		goto out_no_map;
240 	sbi->s_imap = &map[0];
241 	sbi->s_zmap = &map[sbi->s_imap_blocks];
242 
243 	block=2;
244 	for (i=0 ; i < sbi->s_imap_blocks ; i++) {
245 		if (!(sbi->s_imap[i]=sb_bread(s, block)))
246 			goto out_no_bitmap;
247 		block++;
248 	}
249 	for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
250 		if (!(sbi->s_zmap[i]=sb_bread(s, block)))
251 			goto out_no_bitmap;
252 		block++;
253 	}
254 
255 	minix_set_bit(0,sbi->s_imap[0]->b_data);
256 	minix_set_bit(0,sbi->s_zmap[0]->b_data);
257 
258 	/* Apparently minix can create filesystems that allocate more blocks for
259 	 * the bitmaps than needed.  We simply ignore that, but verify it didn't
260 	 * create one with not enough blocks and bail out if so.
261 	 */
262 	block = minix_blocks_needed(sbi->s_ninodes, s->s_blocksize);
263 	if (sbi->s_imap_blocks < block) {
264 		printk("MINIX-fs: file system does not have enough "
265 				"imap blocks allocated.  Refusing to mount.\n");
266 		goto out_no_bitmap;
267 	}
268 
269 	block = minix_blocks_needed(
270 			(sbi->s_nzones - sbi->s_firstdatazone + 1),
271 			s->s_blocksize);
272 	if (sbi->s_zmap_blocks < block) {
273 		printk("MINIX-fs: file system does not have enough "
274 				"zmap blocks allocated.  Refusing to mount.\n");
275 		goto out_no_bitmap;
276 	}
277 
278 	/* set up enough so that it can read an inode */
279 	s->s_op = &minix_sops;
280 	s->s_time_min = 0;
281 	s->s_time_max = U32_MAX;
282 	root_inode = minix_iget(s, MINIX_ROOT_INO);
283 	if (IS_ERR(root_inode)) {
284 		ret = PTR_ERR(root_inode);
285 		goto out_no_root;
286 	}
287 
288 	ret = -ENOMEM;
289 	s->s_root = d_make_root(root_inode);
290 	if (!s->s_root)
291 		goto out_no_root;
292 
293 	if (!sb_rdonly(s)) {
294 		if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
295 			ms->s_state &= ~MINIX_VALID_FS;
296 		mark_buffer_dirty(bh);
297 	}
298 	if (!(sbi->s_mount_state & MINIX_VALID_FS))
299 		printk("MINIX-fs: mounting unchecked file system, "
300 			"running fsck is recommended\n");
301 	else if (sbi->s_mount_state & MINIX_ERROR_FS)
302 		printk("MINIX-fs: mounting file system with errors, "
303 			"running fsck is recommended\n");
304 
305 	return 0;
306 
307 out_no_root:
308 	if (!silent)
309 		printk("MINIX-fs: get root inode failed\n");
310 	goto out_freemap;
311 
312 out_no_bitmap:
313 	printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
314 out_freemap:
315 	for (i = 0; i < sbi->s_imap_blocks; i++)
316 		brelse(sbi->s_imap[i]);
317 	for (i = 0; i < sbi->s_zmap_blocks; i++)
318 		brelse(sbi->s_zmap[i]);
319 	kfree(sbi->s_imap);
320 	goto out_release;
321 
322 out_no_map:
323 	ret = -ENOMEM;
324 	if (!silent)
325 		printk("MINIX-fs: can't allocate map\n");
326 	goto out_release;
327 
328 out_illegal_sb:
329 	if (!silent)
330 		printk("MINIX-fs: bad superblock\n");
331 	goto out_release;
332 
333 out_no_fs:
334 	if (!silent)
335 		printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
336 		       "on device %s.\n", s->s_id);
337 out_release:
338 	brelse(bh);
339 	goto out;
340 
341 out_bad_hblock:
342 	printk("MINIX-fs: blocksize too small for device\n");
343 	goto out;
344 
345 out_bad_sb:
346 	printk("MINIX-fs: unable to read superblock\n");
347 out:
348 	s->s_fs_info = NULL;
349 	kfree(sbi);
350 	return ret;
351 }
352 
353 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
354 {
355 	struct super_block *sb = dentry->d_sb;
356 	struct minix_sb_info *sbi = minix_sb(sb);
357 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
358 	buf->f_type = sb->s_magic;
359 	buf->f_bsize = sb->s_blocksize;
360 	buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
361 	buf->f_bfree = minix_count_free_blocks(sb);
362 	buf->f_bavail = buf->f_bfree;
363 	buf->f_files = sbi->s_ninodes;
364 	buf->f_ffree = minix_count_free_inodes(sb);
365 	buf->f_namelen = sbi->s_namelen;
366 	buf->f_fsid.val[0] = (u32)id;
367 	buf->f_fsid.val[1] = (u32)(id >> 32);
368 
369 	return 0;
370 }
371 
372 static int minix_get_block(struct inode *inode, sector_t block,
373 		    struct buffer_head *bh_result, int create)
374 {
375 	if (INODE_VERSION(inode) == MINIX_V1)
376 		return V1_minix_get_block(inode, block, bh_result, create);
377 	else
378 		return V2_minix_get_block(inode, block, bh_result, create);
379 }
380 
381 static int minix_writepage(struct page *page, struct writeback_control *wbc)
382 {
383 	return block_write_full_page(page, minix_get_block, wbc);
384 }
385 
386 static int minix_readpage(struct file *file, struct page *page)
387 {
388 	return block_read_full_page(page,minix_get_block);
389 }
390 
391 int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
392 {
393 	return __block_write_begin(page, pos, len, minix_get_block);
394 }
395 
396 static void minix_write_failed(struct address_space *mapping, loff_t to)
397 {
398 	struct inode *inode = mapping->host;
399 
400 	if (to > inode->i_size) {
401 		truncate_pagecache(inode, inode->i_size);
402 		minix_truncate(inode);
403 	}
404 }
405 
406 static int minix_write_begin(struct file *file, struct address_space *mapping,
407 			loff_t pos, unsigned len, unsigned flags,
408 			struct page **pagep, void **fsdata)
409 {
410 	int ret;
411 
412 	ret = block_write_begin(mapping, pos, len, flags, pagep,
413 				minix_get_block);
414 	if (unlikely(ret))
415 		minix_write_failed(mapping, pos + len);
416 
417 	return ret;
418 }
419 
420 static sector_t minix_bmap(struct address_space *mapping, sector_t block)
421 {
422 	return generic_block_bmap(mapping,block,minix_get_block);
423 }
424 
425 static const struct address_space_operations minix_aops = {
426 	.readpage = minix_readpage,
427 	.writepage = minix_writepage,
428 	.write_begin = minix_write_begin,
429 	.write_end = generic_write_end,
430 	.bmap = minix_bmap
431 };
432 
433 static const struct inode_operations minix_symlink_inode_operations = {
434 	.get_link	= page_get_link,
435 	.getattr	= minix_getattr,
436 };
437 
438 void minix_set_inode(struct inode *inode, dev_t rdev)
439 {
440 	if (S_ISREG(inode->i_mode)) {
441 		inode->i_op = &minix_file_inode_operations;
442 		inode->i_fop = &minix_file_operations;
443 		inode->i_mapping->a_ops = &minix_aops;
444 	} else if (S_ISDIR(inode->i_mode)) {
445 		inode->i_op = &minix_dir_inode_operations;
446 		inode->i_fop = &minix_dir_operations;
447 		inode->i_mapping->a_ops = &minix_aops;
448 	} else if (S_ISLNK(inode->i_mode)) {
449 		inode->i_op = &minix_symlink_inode_operations;
450 		inode_nohighmem(inode);
451 		inode->i_mapping->a_ops = &minix_aops;
452 	} else
453 		init_special_inode(inode, inode->i_mode, rdev);
454 }
455 
456 /*
457  * The minix V1 function to read an inode.
458  */
459 static struct inode *V1_minix_iget(struct inode *inode)
460 {
461 	struct buffer_head * bh;
462 	struct minix_inode * raw_inode;
463 	struct minix_inode_info *minix_inode = minix_i(inode);
464 	int i;
465 
466 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
467 	if (!raw_inode) {
468 		iget_failed(inode);
469 		return ERR_PTR(-EIO);
470 	}
471 	inode->i_mode = raw_inode->i_mode;
472 	i_uid_write(inode, raw_inode->i_uid);
473 	i_gid_write(inode, raw_inode->i_gid);
474 	set_nlink(inode, raw_inode->i_nlinks);
475 	inode->i_size = raw_inode->i_size;
476 	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = raw_inode->i_time;
477 	inode->i_mtime.tv_nsec = 0;
478 	inode->i_atime.tv_nsec = 0;
479 	inode->i_ctime.tv_nsec = 0;
480 	inode->i_blocks = 0;
481 	for (i = 0; i < 9; i++)
482 		minix_inode->u.i1_data[i] = raw_inode->i_zone[i];
483 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
484 	brelse(bh);
485 	unlock_new_inode(inode);
486 	return inode;
487 }
488 
489 /*
490  * The minix V2 function to read an inode.
491  */
492 static struct inode *V2_minix_iget(struct inode *inode)
493 {
494 	struct buffer_head * bh;
495 	struct minix2_inode * raw_inode;
496 	struct minix_inode_info *minix_inode = minix_i(inode);
497 	int i;
498 
499 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
500 	if (!raw_inode) {
501 		iget_failed(inode);
502 		return ERR_PTR(-EIO);
503 	}
504 	inode->i_mode = raw_inode->i_mode;
505 	i_uid_write(inode, raw_inode->i_uid);
506 	i_gid_write(inode, raw_inode->i_gid);
507 	set_nlink(inode, raw_inode->i_nlinks);
508 	inode->i_size = raw_inode->i_size;
509 	inode->i_mtime.tv_sec = raw_inode->i_mtime;
510 	inode->i_atime.tv_sec = raw_inode->i_atime;
511 	inode->i_ctime.tv_sec = raw_inode->i_ctime;
512 	inode->i_mtime.tv_nsec = 0;
513 	inode->i_atime.tv_nsec = 0;
514 	inode->i_ctime.tv_nsec = 0;
515 	inode->i_blocks = 0;
516 	for (i = 0; i < 10; i++)
517 		minix_inode->u.i2_data[i] = raw_inode->i_zone[i];
518 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
519 	brelse(bh);
520 	unlock_new_inode(inode);
521 	return inode;
522 }
523 
524 /*
525  * The global function to read an inode.
526  */
527 struct inode *minix_iget(struct super_block *sb, unsigned long ino)
528 {
529 	struct inode *inode;
530 
531 	inode = iget_locked(sb, ino);
532 	if (!inode)
533 		return ERR_PTR(-ENOMEM);
534 	if (!(inode->i_state & I_NEW))
535 		return inode;
536 
537 	if (INODE_VERSION(inode) == MINIX_V1)
538 		return V1_minix_iget(inode);
539 	else
540 		return V2_minix_iget(inode);
541 }
542 
543 /*
544  * The minix V1 function to synchronize an inode.
545  */
546 static struct buffer_head * V1_minix_update_inode(struct inode * inode)
547 {
548 	struct buffer_head * bh;
549 	struct minix_inode * raw_inode;
550 	struct minix_inode_info *minix_inode = minix_i(inode);
551 	int i;
552 
553 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
554 	if (!raw_inode)
555 		return NULL;
556 	raw_inode->i_mode = inode->i_mode;
557 	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
558 	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
559 	raw_inode->i_nlinks = inode->i_nlink;
560 	raw_inode->i_size = inode->i_size;
561 	raw_inode->i_time = inode->i_mtime.tv_sec;
562 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
563 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
564 	else for (i = 0; i < 9; i++)
565 		raw_inode->i_zone[i] = minix_inode->u.i1_data[i];
566 	mark_buffer_dirty(bh);
567 	return bh;
568 }
569 
570 /*
571  * The minix V2 function to synchronize an inode.
572  */
573 static struct buffer_head * V2_minix_update_inode(struct inode * inode)
574 {
575 	struct buffer_head * bh;
576 	struct minix2_inode * raw_inode;
577 	struct minix_inode_info *minix_inode = minix_i(inode);
578 	int i;
579 
580 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
581 	if (!raw_inode)
582 		return NULL;
583 	raw_inode->i_mode = inode->i_mode;
584 	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
585 	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
586 	raw_inode->i_nlinks = inode->i_nlink;
587 	raw_inode->i_size = inode->i_size;
588 	raw_inode->i_mtime = inode->i_mtime.tv_sec;
589 	raw_inode->i_atime = inode->i_atime.tv_sec;
590 	raw_inode->i_ctime = inode->i_ctime.tv_sec;
591 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
592 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
593 	else for (i = 0; i < 10; i++)
594 		raw_inode->i_zone[i] = minix_inode->u.i2_data[i];
595 	mark_buffer_dirty(bh);
596 	return bh;
597 }
598 
599 static int minix_write_inode(struct inode *inode, struct writeback_control *wbc)
600 {
601 	int err = 0;
602 	struct buffer_head *bh;
603 
604 	if (INODE_VERSION(inode) == MINIX_V1)
605 		bh = V1_minix_update_inode(inode);
606 	else
607 		bh = V2_minix_update_inode(inode);
608 	if (!bh)
609 		return -EIO;
610 	if (wbc->sync_mode == WB_SYNC_ALL && buffer_dirty(bh)) {
611 		sync_dirty_buffer(bh);
612 		if (buffer_req(bh) && !buffer_uptodate(bh)) {
613 			printk("IO error syncing minix inode [%s:%08lx]\n",
614 				inode->i_sb->s_id, inode->i_ino);
615 			err = -EIO;
616 		}
617 	}
618 	brelse (bh);
619 	return err;
620 }
621 
622 int minix_getattr(const struct path *path, struct kstat *stat,
623 		  u32 request_mask, unsigned int flags)
624 {
625 	struct super_block *sb = path->dentry->d_sb;
626 	struct inode *inode = d_inode(path->dentry);
627 
628 	generic_fillattr(inode, stat);
629 	if (INODE_VERSION(inode) == MINIX_V1)
630 		stat->blocks = (BLOCK_SIZE / 512) * V1_minix_blocks(stat->size, sb);
631 	else
632 		stat->blocks = (sb->s_blocksize / 512) * V2_minix_blocks(stat->size, sb);
633 	stat->blksize = sb->s_blocksize;
634 	return 0;
635 }
636 
637 /*
638  * The function that is called for file truncation.
639  */
640 void minix_truncate(struct inode * inode)
641 {
642 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
643 		return;
644 	if (INODE_VERSION(inode) == MINIX_V1)
645 		V1_minix_truncate(inode);
646 	else
647 		V2_minix_truncate(inode);
648 }
649 
650 static struct dentry *minix_mount(struct file_system_type *fs_type,
651 	int flags, const char *dev_name, void *data)
652 {
653 	return mount_bdev(fs_type, flags, dev_name, data, minix_fill_super);
654 }
655 
656 static struct file_system_type minix_fs_type = {
657 	.owner		= THIS_MODULE,
658 	.name		= "minix",
659 	.mount		= minix_mount,
660 	.kill_sb	= kill_block_super,
661 	.fs_flags	= FS_REQUIRES_DEV,
662 };
663 MODULE_ALIAS_FS("minix");
664 
665 static int __init init_minix_fs(void)
666 {
667 	int err = init_inodecache();
668 	if (err)
669 		goto out1;
670 	err = register_filesystem(&minix_fs_type);
671 	if (err)
672 		goto out;
673 	return 0;
674 out:
675 	destroy_inodecache();
676 out1:
677 	return err;
678 }
679 
680 static void __exit exit_minix_fs(void)
681 {
682         unregister_filesystem(&minix_fs_type);
683 	destroy_inodecache();
684 }
685 
686 module_init(init_minix_fs)
687 module_exit(exit_minix_fs)
688 MODULE_LICENSE("GPL");
689 
690