xref: /linux/fs/minix/inode.c (revision 8c97a6ddc95690a938ded44b4e3202f03f15078c)
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/mpage.h>
21 #include <linux/vfs.h>
22 #include <linux/writeback.h>
23 #include <linux/fs_context.h>
24 
25 static int minix_write_inode(struct inode *inode,
26 		struct writeback_control *wbc);
27 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf);
28 
29 void __minix_error_inode(struct inode *inode, const char *function,
30 			 unsigned int line, const char *fmt, ...)
31 {
32 	struct va_format vaf;
33 	va_list args;
34 
35 	va_start(args, fmt);
36 	vaf.fmt = fmt;
37 	vaf.va = &args;
38 	printk(KERN_CRIT "minix-fs error (device %s): %s:%d: "
39 	       "inode #%lu: comm %s: %pV\n",
40 	       inode->i_sb->s_id, function, line, inode->i_ino,
41 	       current->comm, &vaf);
42 	va_end(args);
43 }
44 
45 static void minix_evict_inode(struct inode *inode)
46 {
47 	truncate_inode_pages_final(&inode->i_data);
48 	if (!inode->i_nlink) {
49 		inode->i_size = 0;
50 		minix_truncate(inode);
51 	}
52 	invalidate_inode_buffers(inode);
53 	clear_inode(inode);
54 	if (!inode->i_nlink)
55 		minix_free_inode(inode);
56 }
57 
58 static void minix_put_super(struct super_block *sb)
59 {
60 	int i;
61 	struct minix_sb_info *sbi = minix_sb(sb);
62 
63 	if (!sb_rdonly(sb)) {
64 		if (sbi->s_version != MINIX_V3)	 /* s_state is now out from V3 sb */
65 			sbi->s_ms->s_state = sbi->s_mount_state;
66 		mark_buffer_dirty(sbi->s_sbh);
67 	}
68 	for (i = 0; i < sbi->s_imap_blocks; i++)
69 		brelse(sbi->s_imap[i]);
70 	for (i = 0; i < sbi->s_zmap_blocks; i++)
71 		brelse(sbi->s_zmap[i]);
72 	brelse (sbi->s_sbh);
73 	kfree(sbi->s_imap);
74 	sb->s_fs_info = NULL;
75 	kfree(sbi);
76 }
77 
78 static struct kmem_cache * minix_inode_cachep;
79 
80 static struct inode *minix_alloc_inode(struct super_block *sb)
81 {
82 	struct minix_inode_info *ei;
83 	ei = alloc_inode_sb(sb, minix_inode_cachep, GFP_KERNEL);
84 	if (!ei)
85 		return NULL;
86 	return &ei->vfs_inode;
87 }
88 
89 static void minix_free_in_core_inode(struct inode *inode)
90 {
91 	kmem_cache_free(minix_inode_cachep, minix_i(inode));
92 }
93 
94 static void init_once(void *foo)
95 {
96 	struct minix_inode_info *ei = (struct minix_inode_info *) foo;
97 
98 	inode_init_once(&ei->vfs_inode);
99 }
100 
101 static int __init init_inodecache(void)
102 {
103 	minix_inode_cachep = kmem_cache_create("minix_inode_cache",
104 					     sizeof(struct minix_inode_info),
105 					     0, (SLAB_RECLAIM_ACCOUNT|
106 						SLAB_ACCOUNT),
107 					     init_once);
108 	if (minix_inode_cachep == NULL)
109 		return -ENOMEM;
110 	return 0;
111 }
112 
113 static void destroy_inodecache(void)
114 {
115 	/*
116 	 * Make sure all delayed rcu free inodes are flushed before we
117 	 * destroy cache.
118 	 */
119 	rcu_barrier();
120 	kmem_cache_destroy(minix_inode_cachep);
121 }
122 
123 static const struct super_operations minix_sops = {
124 	.alloc_inode	= minix_alloc_inode,
125 	.free_inode	= minix_free_in_core_inode,
126 	.write_inode	= minix_write_inode,
127 	.evict_inode	= minix_evict_inode,
128 	.put_super	= minix_put_super,
129 	.statfs		= minix_statfs,
130 };
131 
132 static int minix_reconfigure(struct fs_context *fc)
133 {
134 	struct minix_super_block * ms;
135 	struct super_block *sb = fc->root->d_sb;
136 	struct minix_sb_info * sbi = sb->s_fs_info;
137 
138 	sync_filesystem(sb);
139 	ms = sbi->s_ms;
140 	if ((bool)(fc->sb_flags & SB_RDONLY) == sb_rdonly(sb))
141 		return 0;
142 	if (fc->sb_flags & SB_RDONLY) {
143 		if (ms->s_state & MINIX_VALID_FS ||
144 		    !(sbi->s_mount_state & MINIX_VALID_FS))
145 			return 0;
146 		/* Mounting a rw partition read-only. */
147 		if (sbi->s_version != MINIX_V3)
148 			ms->s_state = sbi->s_mount_state;
149 		mark_buffer_dirty(sbi->s_sbh);
150 	} else {
151 	  	/* Mount a partition which is read-only, read-write. */
152 		if (sbi->s_version != MINIX_V3) {
153 			sbi->s_mount_state = ms->s_state;
154 			ms->s_state &= ~MINIX_VALID_FS;
155 		} else {
156 			sbi->s_mount_state = MINIX_VALID_FS;
157 		}
158 		mark_buffer_dirty(sbi->s_sbh);
159 
160 		if (!(sbi->s_mount_state & MINIX_VALID_FS))
161 			printk("MINIX-fs warning: remounting unchecked fs, "
162 				"running fsck is recommended\n");
163 		else if ((sbi->s_mount_state & MINIX_ERROR_FS))
164 			printk("MINIX-fs warning: remounting fs with errors, "
165 				"running fsck is recommended\n");
166 	}
167 	return 0;
168 }
169 
170 static bool minix_check_superblock(struct super_block *sb)
171 {
172 	struct minix_sb_info *sbi = minix_sb(sb);
173 	unsigned long block;
174 
175 	if (sbi->s_log_zone_size != 0) {
176 		printk("minix-fs error: zone size must equal block size. "
177 		       "s_log_zone_size > 0 is not supported.\n");
178 		return false;
179 	}
180 
181 	if (sbi->s_ninodes < 1 || sbi->s_firstdatazone <= 4 ||
182 	    sbi->s_firstdatazone >= sbi->s_nzones)
183 		return false;
184 
185 	/* Apparently minix can create filesystems that allocate more blocks for
186 	 * the bitmaps than needed.  We simply ignore that, but verify it didn't
187 	 * create one with not enough blocks and bail out if so.
188 	 */
189 	block = minix_blocks_needed(sbi->s_ninodes, sb->s_blocksize);
190 	if (sbi->s_imap_blocks < block) {
191 		printk("MINIX-fs: file system does not have enough "
192 		       "imap blocks allocated. Refusing to mount.\n");
193 		return false;
194 	}
195 
196 	block = minix_blocks_needed(
197 			(sbi->s_nzones - sbi->s_firstdatazone + 1),
198 			sb->s_blocksize);
199 	if (sbi->s_zmap_blocks < block) {
200 		printk("MINIX-fs: file system does not have enough "
201 		       "zmap blocks allocated. Refusing to mount.\n");
202 		return false;
203 	}
204 
205 	/*
206 	 * s_max_size must not exceed the block mapping limitation.  This check
207 	 * is only needed for V1 filesystems, since V2/V3 support an extra level
208 	 * of indirect blocks which places the limit well above U32_MAX.
209 	 */
210 	if (sbi->s_version == MINIX_V1 &&
211 	    sb->s_maxbytes > (7 + 512 + 512*512) * BLOCK_SIZE)
212 		return false;
213 
214 	return true;
215 }
216 
217 static int minix_fill_super(struct super_block *s, struct fs_context *fc)
218 {
219 	struct buffer_head *bh;
220 	struct buffer_head **map;
221 	struct minix_super_block *ms;
222 	struct minix3_super_block *m3s = NULL;
223 	unsigned long i, block;
224 	struct inode *root_inode;
225 	struct minix_sb_info *sbi;
226 	int ret = -EINVAL;
227 	int silent = fc->sb_flags & SB_SILENT;
228 
229 	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
230 	if (!sbi)
231 		return -ENOMEM;
232 	s->s_fs_info = sbi;
233 
234 	BUILD_BUG_ON(32 != sizeof (struct minix_inode));
235 	BUILD_BUG_ON(64 != sizeof(struct minix2_inode));
236 
237 	if (!sb_set_blocksize(s, BLOCK_SIZE))
238 		goto out_bad_hblock;
239 
240 	if (!(bh = sb_bread(s, 1)))
241 		goto out_bad_sb;
242 
243 	ms = (struct minix_super_block *) bh->b_data;
244 	sbi->s_ms = ms;
245 	sbi->s_sbh = bh;
246 	sbi->s_mount_state = ms->s_state;
247 	sbi->s_ninodes = ms->s_ninodes;
248 	sbi->s_nzones = ms->s_nzones;
249 	sbi->s_imap_blocks = ms->s_imap_blocks;
250 	sbi->s_zmap_blocks = ms->s_zmap_blocks;
251 	sbi->s_firstdatazone = ms->s_firstdatazone;
252 	sbi->s_log_zone_size = ms->s_log_zone_size;
253 	s->s_maxbytes = ms->s_max_size;
254 	s->s_magic = ms->s_magic;
255 	if (s->s_magic == MINIX_SUPER_MAGIC) {
256 		sbi->s_version = MINIX_V1;
257 		sbi->s_dirsize = 16;
258 		sbi->s_namelen = 14;
259 		s->s_max_links = MINIX_LINK_MAX;
260 	} else if (s->s_magic == MINIX_SUPER_MAGIC2) {
261 		sbi->s_version = MINIX_V1;
262 		sbi->s_dirsize = 32;
263 		sbi->s_namelen = 30;
264 		s->s_max_links = MINIX_LINK_MAX;
265 	} else if (s->s_magic == MINIX2_SUPER_MAGIC) {
266 		sbi->s_version = MINIX_V2;
267 		sbi->s_nzones = ms->s_zones;
268 		sbi->s_dirsize = 16;
269 		sbi->s_namelen = 14;
270 		s->s_max_links = MINIX2_LINK_MAX;
271 	} else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
272 		sbi->s_version = MINIX_V2;
273 		sbi->s_nzones = ms->s_zones;
274 		sbi->s_dirsize = 32;
275 		sbi->s_namelen = 30;
276 		s->s_max_links = MINIX2_LINK_MAX;
277 	} else if ( *(__u16 *)(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
278 		m3s = (struct minix3_super_block *) bh->b_data;
279 		s->s_magic = m3s->s_magic;
280 		sbi->s_imap_blocks = m3s->s_imap_blocks;
281 		sbi->s_zmap_blocks = m3s->s_zmap_blocks;
282 		sbi->s_firstdatazone = m3s->s_firstdatazone;
283 		sbi->s_log_zone_size = m3s->s_log_zone_size;
284 		s->s_maxbytes = m3s->s_max_size;
285 		sbi->s_ninodes = m3s->s_ninodes;
286 		sbi->s_nzones = m3s->s_zones;
287 		sbi->s_dirsize = 64;
288 		sbi->s_namelen = 60;
289 		sbi->s_version = MINIX_V3;
290 		sbi->s_mount_state = MINIX_VALID_FS;
291 		sb_set_blocksize(s, m3s->s_blocksize);
292 		s->s_max_links = MINIX2_LINK_MAX;
293 	} else
294 		goto out_no_fs;
295 
296 	if (!minix_check_superblock(s))
297 		goto out_illegal_sb;
298 
299 	/*
300 	 * Allocate the buffer map to keep the superblock small.
301 	 */
302 	i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
303 	map = kzalloc(i, GFP_KERNEL);
304 	if (!map)
305 		goto out_no_map;
306 	sbi->s_imap = &map[0];
307 	sbi->s_zmap = &map[sbi->s_imap_blocks];
308 
309 	block=2;
310 	for (i=0 ; i < sbi->s_imap_blocks ; i++) {
311 		if (!(sbi->s_imap[i]=sb_bread(s, block)))
312 			goto out_no_bitmap;
313 		block++;
314 	}
315 	for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
316 		if (!(sbi->s_zmap[i]=sb_bread(s, block)))
317 			goto out_no_bitmap;
318 		block++;
319 	}
320 
321 	minix_set_bit(0,sbi->s_imap[0]->b_data);
322 	minix_set_bit(0,sbi->s_zmap[0]->b_data);
323 
324 	/* set up enough so that it can read an inode */
325 	s->s_op = &minix_sops;
326 	s->s_time_min = 0;
327 	s->s_time_max = U32_MAX;
328 	root_inode = minix_iget(s, MINIX_ROOT_INO);
329 	if (IS_ERR(root_inode)) {
330 		ret = PTR_ERR(root_inode);
331 		goto out_no_root;
332 	}
333 
334 	ret = -ENOMEM;
335 	s->s_root = d_make_root(root_inode);
336 	if (!s->s_root)
337 		goto out_no_root;
338 
339 	if (!sb_rdonly(s)) {
340 		if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
341 			ms->s_state &= ~MINIX_VALID_FS;
342 		mark_buffer_dirty(bh);
343 	}
344 	if (!(sbi->s_mount_state & MINIX_VALID_FS))
345 		printk("MINIX-fs: mounting unchecked file system, "
346 			"running fsck is recommended\n");
347 	else if (sbi->s_mount_state & MINIX_ERROR_FS)
348 		printk("MINIX-fs: mounting file system with errors, "
349 			"running fsck is recommended\n");
350 
351 	return 0;
352 
353 out_no_root:
354 	if (!silent)
355 		printk("MINIX-fs: get root inode failed\n");
356 	goto out_freemap;
357 
358 out_no_bitmap:
359 	printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
360 out_freemap:
361 	for (i = 0; i < sbi->s_imap_blocks; i++)
362 		brelse(sbi->s_imap[i]);
363 	for (i = 0; i < sbi->s_zmap_blocks; i++)
364 		brelse(sbi->s_zmap[i]);
365 	kfree(sbi->s_imap);
366 	goto out_release;
367 
368 out_no_map:
369 	ret = -ENOMEM;
370 	if (!silent)
371 		printk("MINIX-fs: can't allocate map\n");
372 	goto out_release;
373 
374 out_illegal_sb:
375 	if (!silent)
376 		printk("MINIX-fs: bad superblock\n");
377 	goto out_release;
378 
379 out_no_fs:
380 	if (!silent)
381 		printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
382 		       "on device %s.\n", s->s_id);
383 out_release:
384 	brelse(bh);
385 	goto out;
386 
387 out_bad_hblock:
388 	printk("MINIX-fs: blocksize too small for device\n");
389 	goto out;
390 
391 out_bad_sb:
392 	printk("MINIX-fs: unable to read superblock\n");
393 out:
394 	s->s_fs_info = NULL;
395 	kfree(sbi);
396 	return ret;
397 }
398 
399 static int minix_get_tree(struct fs_context *fc)
400 {
401 	 return get_tree_bdev(fc, minix_fill_super);
402 }
403 
404 static const struct fs_context_operations minix_context_ops = {
405 	.get_tree	= minix_get_tree,
406 	.reconfigure	= minix_reconfigure,
407 };
408 
409 static int minix_init_fs_context(struct fs_context *fc)
410 {
411 	fc->ops = &minix_context_ops;
412 
413 	return 0;
414 }
415 
416 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
417 {
418 	struct super_block *sb = dentry->d_sb;
419 	struct minix_sb_info *sbi = minix_sb(sb);
420 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
421 	buf->f_type = sb->s_magic;
422 	buf->f_bsize = sb->s_blocksize;
423 	buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
424 	buf->f_bfree = minix_count_free_blocks(sb);
425 	buf->f_bavail = buf->f_bfree;
426 	buf->f_files = sbi->s_ninodes;
427 	buf->f_ffree = minix_count_free_inodes(sb);
428 	buf->f_namelen = sbi->s_namelen;
429 	buf->f_fsid = u64_to_fsid(id);
430 
431 	return 0;
432 }
433 
434 static int minix_get_block(struct inode *inode, sector_t block,
435 		    struct buffer_head *bh_result, int create)
436 {
437 	if (INODE_VERSION(inode) == MINIX_V1)
438 		return V1_minix_get_block(inode, block, bh_result, create);
439 	else
440 		return V2_minix_get_block(inode, block, bh_result, create);
441 }
442 
443 static int minix_writepages(struct address_space *mapping,
444 		struct writeback_control *wbc)
445 {
446 	return mpage_writepages(mapping, wbc, minix_get_block);
447 }
448 
449 static int minix_read_folio(struct file *file, struct folio *folio)
450 {
451 	return block_read_full_folio(folio, minix_get_block);
452 }
453 
454 int minix_prepare_chunk(struct folio *folio, loff_t pos, unsigned len)
455 {
456 	return __block_write_begin(folio, pos, len, minix_get_block);
457 }
458 
459 static void minix_write_failed(struct address_space *mapping, loff_t to)
460 {
461 	struct inode *inode = mapping->host;
462 
463 	if (to > inode->i_size) {
464 		truncate_pagecache(inode, inode->i_size);
465 		minix_truncate(inode);
466 	}
467 }
468 
469 static int minix_write_begin(const struct kiocb *iocb,
470 			     struct address_space *mapping,
471 			     loff_t pos, unsigned len,
472 			     struct folio **foliop, void **fsdata)
473 {
474 	int ret;
475 
476 	ret = block_write_begin(mapping, pos, len, foliop, minix_get_block);
477 	if (unlikely(ret))
478 		minix_write_failed(mapping, pos + len);
479 
480 	return ret;
481 }
482 
483 static sector_t minix_bmap(struct address_space *mapping, sector_t block)
484 {
485 	return generic_block_bmap(mapping,block,minix_get_block);
486 }
487 
488 static const struct address_space_operations minix_aops = {
489 	.dirty_folio	= block_dirty_folio,
490 	.invalidate_folio = block_invalidate_folio,
491 	.read_folio = minix_read_folio,
492 	.writepages = minix_writepages,
493 	.write_begin = minix_write_begin,
494 	.write_end = generic_write_end,
495 	.migrate_folio = buffer_migrate_folio,
496 	.bmap = minix_bmap,
497 	.direct_IO = noop_direct_IO
498 };
499 
500 static const struct inode_operations minix_symlink_inode_operations = {
501 	.get_link	= page_get_link,
502 	.getattr	= minix_getattr,
503 };
504 
505 void minix_set_inode(struct inode *inode, dev_t rdev)
506 {
507 	if (S_ISREG(inode->i_mode)) {
508 		inode->i_op = &minix_file_inode_operations;
509 		inode->i_fop = &minix_file_operations;
510 		inode->i_mapping->a_ops = &minix_aops;
511 	} else if (S_ISDIR(inode->i_mode)) {
512 		inode->i_op = &minix_dir_inode_operations;
513 		inode->i_fop = &minix_dir_operations;
514 		inode->i_mapping->a_ops = &minix_aops;
515 	} else if (S_ISLNK(inode->i_mode)) {
516 		inode->i_op = &minix_symlink_inode_operations;
517 		inode_nohighmem(inode);
518 		inode->i_mapping->a_ops = &minix_aops;
519 	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
520 		   S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
521 		init_special_inode(inode, inode->i_mode, rdev);
522 	} else {
523 		printk(KERN_DEBUG "MINIX-fs: Invalid file type 0%04o for inode %lu.\n",
524 		       inode->i_mode, inode->i_ino);
525 		make_bad_inode(inode);
526 	}
527 }
528 
529 /*
530  * The minix V1 function to read an inode.
531  */
532 static struct inode *V1_minix_iget(struct inode *inode)
533 {
534 	struct buffer_head * bh;
535 	struct minix_inode * raw_inode;
536 	struct minix_inode_info *minix_inode = minix_i(inode);
537 	int i;
538 
539 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
540 	if (!raw_inode) {
541 		iget_failed(inode);
542 		return ERR_PTR(-EIO);
543 	}
544 	if (raw_inode->i_nlinks == 0) {
545 		printk("MINIX-fs: deleted inode referenced: %lu\n",
546 		       inode->i_ino);
547 		brelse(bh);
548 		iget_failed(inode);
549 		return ERR_PTR(-ESTALE);
550 	}
551 	inode->i_mode = raw_inode->i_mode;
552 	i_uid_write(inode, raw_inode->i_uid);
553 	i_gid_write(inode, raw_inode->i_gid);
554 	set_nlink(inode, raw_inode->i_nlinks);
555 	inode->i_size = raw_inode->i_size;
556 	inode_set_mtime_to_ts(inode,
557 			      inode_set_atime_to_ts(inode, inode_set_ctime(inode, raw_inode->i_time, 0)));
558 	inode->i_blocks = 0;
559 	for (i = 0; i < 9; i++)
560 		minix_inode->u.i1_data[i] = raw_inode->i_zone[i];
561 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
562 	brelse(bh);
563 	unlock_new_inode(inode);
564 	return inode;
565 }
566 
567 /*
568  * The minix V2 function to read an inode.
569  */
570 static struct inode *V2_minix_iget(struct inode *inode)
571 {
572 	struct buffer_head * bh;
573 	struct minix2_inode * raw_inode;
574 	struct minix_inode_info *minix_inode = minix_i(inode);
575 	int i;
576 
577 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
578 	if (!raw_inode) {
579 		iget_failed(inode);
580 		return ERR_PTR(-EIO);
581 	}
582 	if (raw_inode->i_nlinks == 0) {
583 		printk("MINIX-fs: deleted inode referenced: %lu\n",
584 		       inode->i_ino);
585 		brelse(bh);
586 		iget_failed(inode);
587 		return ERR_PTR(-ESTALE);
588 	}
589 	inode->i_mode = raw_inode->i_mode;
590 	i_uid_write(inode, raw_inode->i_uid);
591 	i_gid_write(inode, raw_inode->i_gid);
592 	set_nlink(inode, raw_inode->i_nlinks);
593 	inode->i_size = raw_inode->i_size;
594 	inode_set_mtime(inode, raw_inode->i_mtime, 0);
595 	inode_set_atime(inode, raw_inode->i_atime, 0);
596 	inode_set_ctime(inode, raw_inode->i_ctime, 0);
597 	inode->i_blocks = 0;
598 	for (i = 0; i < 10; i++)
599 		minix_inode->u.i2_data[i] = raw_inode->i_zone[i];
600 	minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
601 	brelse(bh);
602 	unlock_new_inode(inode);
603 	return inode;
604 }
605 
606 /*
607  * The global function to read an inode.
608  */
609 struct inode *minix_iget(struct super_block *sb, unsigned long ino)
610 {
611 	struct inode *inode;
612 
613 	inode = iget_locked(sb, ino);
614 	if (!inode)
615 		return ERR_PTR(-ENOMEM);
616 	if (!(inode_state_read_once(inode) & I_NEW))
617 		return inode;
618 
619 	if (INODE_VERSION(inode) == MINIX_V1)
620 		return V1_minix_iget(inode);
621 	else
622 		return V2_minix_iget(inode);
623 }
624 
625 /*
626  * The minix V1 function to synchronize an inode.
627  */
628 static struct buffer_head * V1_minix_update_inode(struct inode * inode)
629 {
630 	struct buffer_head * bh;
631 	struct minix_inode * raw_inode;
632 	struct minix_inode_info *minix_inode = minix_i(inode);
633 	int i;
634 
635 	raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
636 	if (!raw_inode)
637 		return NULL;
638 	raw_inode->i_mode = inode->i_mode;
639 	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
640 	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
641 	raw_inode->i_nlinks = inode->i_nlink;
642 	raw_inode->i_size = inode->i_size;
643 	raw_inode->i_time = inode_get_mtime_sec(inode);
644 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
645 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
646 	else for (i = 0; i < 9; i++)
647 		raw_inode->i_zone[i] = minix_inode->u.i1_data[i];
648 	mark_buffer_dirty(bh);
649 	return bh;
650 }
651 
652 /*
653  * The minix V2 function to synchronize an inode.
654  */
655 static struct buffer_head * V2_minix_update_inode(struct inode * inode)
656 {
657 	struct buffer_head * bh;
658 	struct minix2_inode * raw_inode;
659 	struct minix_inode_info *minix_inode = minix_i(inode);
660 	int i;
661 
662 	raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
663 	if (!raw_inode)
664 		return NULL;
665 	raw_inode->i_mode = inode->i_mode;
666 	raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
667 	raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
668 	raw_inode->i_nlinks = inode->i_nlink;
669 	raw_inode->i_size = inode->i_size;
670 	raw_inode->i_mtime = inode_get_mtime_sec(inode);
671 	raw_inode->i_atime = inode_get_atime_sec(inode);
672 	raw_inode->i_ctime = inode_get_ctime_sec(inode);
673 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
674 		raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
675 	else for (i = 0; i < 10; i++)
676 		raw_inode->i_zone[i] = minix_inode->u.i2_data[i];
677 	mark_buffer_dirty(bh);
678 	return bh;
679 }
680 
681 static int minix_write_inode(struct inode *inode, struct writeback_control *wbc)
682 {
683 	int err = 0;
684 	struct buffer_head *bh;
685 
686 	if (INODE_VERSION(inode) == MINIX_V1)
687 		bh = V1_minix_update_inode(inode);
688 	else
689 		bh = V2_minix_update_inode(inode);
690 	if (!bh)
691 		return -EIO;
692 	if (wbc->sync_mode == WB_SYNC_ALL && buffer_dirty(bh)) {
693 		sync_dirty_buffer(bh);
694 		if (buffer_req(bh) && !buffer_uptodate(bh)) {
695 			printk("IO error syncing minix inode [%s:%08lx]\n",
696 				inode->i_sb->s_id, inode->i_ino);
697 			err = -EIO;
698 		}
699 	}
700 	brelse (bh);
701 	return err;
702 }
703 
704 int minix_getattr(struct mnt_idmap *idmap, const struct path *path,
705 		  struct kstat *stat, u32 request_mask, unsigned int flags)
706 {
707 	struct super_block *sb = path->dentry->d_sb;
708 	struct inode *inode = d_inode(path->dentry);
709 
710 	generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
711 	if (INODE_VERSION(inode) == MINIX_V1)
712 		stat->blocks = (BLOCK_SIZE / 512) * V1_minix_blocks(stat->size, sb);
713 	else
714 		stat->blocks = (sb->s_blocksize / 512) * V2_minix_blocks(stat->size, sb);
715 	stat->blksize = sb->s_blocksize;
716 	return 0;
717 }
718 
719 /*
720  * The function that is called for file truncation.
721  */
722 void minix_truncate(struct inode * inode)
723 {
724 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
725 		return;
726 	if (INODE_VERSION(inode) == MINIX_V1)
727 		V1_minix_truncate(inode);
728 	else
729 		V2_minix_truncate(inode);
730 }
731 
732 static struct file_system_type minix_fs_type = {
733 	.owner			= THIS_MODULE,
734 	.name			= "minix",
735 	.kill_sb		= kill_block_super,
736 	.fs_flags		= FS_REQUIRES_DEV,
737 	.init_fs_context	= minix_init_fs_context,
738 };
739 MODULE_ALIAS_FS("minix");
740 
741 static int __init init_minix_fs(void)
742 {
743 	int err = init_inodecache();
744 	if (err)
745 		goto out1;
746 	err = register_filesystem(&minix_fs_type);
747 	if (err)
748 		goto out;
749 	return 0;
750 out:
751 	destroy_inodecache();
752 out1:
753 	return err;
754 }
755 
756 static void __exit exit_minix_fs(void)
757 {
758         unregister_filesystem(&minix_fs_type);
759 	destroy_inodecache();
760 }
761 
762 module_init(init_minix_fs)
763 module_exit(exit_minix_fs)
764 MODULE_DESCRIPTION("Minix file system");
765 MODULE_LICENSE("GPL");
766 
767