summaryrefslogtreecommitdiff
path: root/fs/befs/linuxvfs.c
blob: be383fa46b12a8514d440b04941aa31ff1f5bc69 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/fs/befs/linuxvfs.c
 *
 * Copyright (C) 2001 Will Dyson <will_dyson@pobox.com
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/nls.h>
#include <linux/buffer_head.h>
#include <linux/vfs.h>
#include <linux/parser.h>
#include <linux/namei.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/exportfs.h>
#include <linux/seq_file.h>
#include <linux/blkdev.h>

#include "befs.h"
#include "btree.h"
#include "inode.h"
#include "datastream.h"
#include "super.h"
#include "io.h"

MODULE_DESCRIPTION("BeOS File System (BeFS) driver");
MODULE_AUTHOR("Will Dyson");
MODULE_LICENSE("GPL");

/* The units the vfs expects inode->i_blocks to be in */
#define VFS_BLOCK_SIZE 512

static int befs_readdir(struct file *, struct dir_context *);
static int befs_get_block(struct inode *, sector_t, struct buffer_head *, int);
static int befs_read_folio(struct file *file, struct folio *folio);
static sector_t befs_bmap(struct address_space *mapping, sector_t block);
static struct dentry *befs_lookup(struct inode *, struct dentry *,
				  unsigned int);
static struct inode *befs_iget(struct super_block *, unsigned long);
static struct inode *befs_alloc_inode(struct super_block *sb);
static void befs_free_inode(struct inode *inode);
static void befs_destroy_inodecache(void);
static int befs_symlink_read_folio(struct file *, struct folio *);
static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
			char **out, int *out_len);
static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
			char **out, int *out_len);
static void befs_put_super(struct super_block *);
static int befs_remount(struct super_block *, int *, char *);
static int befs_statfs(struct dentry *, struct kstatfs *);
static int befs_show_options(struct seq_file *, struct dentry *);
static int parse_options(char *, struct befs_mount_options *);
static struct dentry *befs_fh_to_dentry(struct super_block *sb,
				struct fid *fid, int fh_len, int fh_type);
static struct dentry *befs_fh_to_parent(struct super_block *sb,
				struct fid *fid, int fh_len, int fh_type);
static struct dentry *befs_get_parent(struct dentry *child);

static const struct super_operations befs_sops = {
	.alloc_inode	= befs_alloc_inode,	/* allocate a new inode */
	.free_inode	= befs_free_inode, /* deallocate an inode */
	.put_super	= befs_put_super,	/* uninit super */
	.statfs		= befs_statfs,	/* statfs */
	.remount_fs	= befs_remount,
	.show_options	= befs_show_options,
};

/* slab cache for befs_inode_info objects */
static struct kmem_cache *befs_inode_cachep;

static const struct file_operations befs_dir_operations = {
	.read		= generic_read_dir,
	.iterate_shared	= befs_readdir,
	.llseek		= generic_file_llseek,
};

static const struct inode_operations befs_dir_inode_operations = {
	.lookup		= befs_lookup,
};

static const struct address_space_operations befs_aops = {
	.read_folio	= befs_read_folio,
	.bmap		= befs_bmap,
};

static const struct address_space_operations befs_symlink_aops = {
	.read_folio	= befs_symlink_read_folio,
};

static const struct export_operations befs_export_operations = {
	.fh_to_dentry	= befs_fh_to_dentry,
	.fh_to_parent	= befs_fh_to_parent,
	.get_parent	= befs_get_parent,
};

/*
 * Called by generic_file_read() to read a folio of data
 *
 * In turn, simply calls a generic block read function and
 * passes it the address of befs_get_block, for mapping file
 * positions to disk blocks.
 */
static int
befs_read_folio(struct file *file, struct folio *folio)
{
	return block_read_full_folio(folio, befs_get_block);
}

static sector_t
befs_bmap(struct address_space *mapping, sector_t block)
{
	return generic_block_bmap(mapping, block, befs_get_block);
}

/*
 * Generic function to map a file position (block) to a
 * disk offset (passed back in bh_result).
 *
 * Used by many higher level functions.
 *
 * Calls befs_fblock2brun() in datastream.c to do the real work.
 */

static int
befs_get_block(struct inode *inode, sector_t block,
	       struct buffer_head *bh_result, int create)
{
	struct super_block *sb = inode->i_sb;
	befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
	befs_block_run run = BAD_IADDR;
	int res;
	ulong disk_off;

	befs_debug(sb, "---> befs_get_block() for inode %lu, block %ld",
		   (unsigned long)inode->i_ino, (long)block);
	if (create) {
		befs_error(sb, "befs_get_block() was asked to write to "
			   "block %ld in inode %lu", (long)block,
			   (unsigned long)inode->i_ino);
		return -EPERM;
	}

	res = befs_fblock2brun(sb, ds, block, &run);
	if (res != BEFS_OK) {
		befs_error(sb,
			   "<--- %s for inode %lu, block %ld ERROR",
			   __func__, (unsigned long)inode->i_ino,
			   (long)block);
		return -EFBIG;
	}

	disk_off = (ulong) iaddr2blockno(sb, &run);

	map_bh(bh_result, inode->i_sb, disk_off);

	befs_debug(sb, "<--- %s for inode %lu, block %ld, disk address %lu",
		  __func__, (unsigned long)inode->i_ino, (long)block,
		  (unsigned long)disk_off);

	return 0;
}

static struct dentry *
befs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
	struct inode *inode;
	struct super_block *sb = dir->i_sb;
	const befs_data_stream *ds = &BEFS_I(dir)->i_data.ds;
	befs_off_t offset;
	int ret;
	int utfnamelen;
	char *utfname;
	const char *name = dentry->d_name.name;

	befs_debug(sb, "---> %s name %pd inode %ld", __func__,
		   dentry, dir->i_ino);

	/* Convert to UTF-8 */
	if (BEFS_SB(sb)->nls) {
		ret =
		    befs_nls2utf(sb, name, strlen(name), &utfname, &utfnamelen);
		if (ret < 0) {
			befs_debug(sb, "<--- %s ERROR", __func__);
			return ERR_PTR(ret);
		}
		ret = befs_btree_find(sb, ds, utfname, &offset);
		kfree(utfname);

	} else {
		ret = befs_btree_find(sb, ds, name, &offset);
	}

	if (ret == BEFS_BT_NOT_FOUND) {
		befs_debug(sb, "<--- %s %pd not found", __func__, dentry);
		inode = NULL;
	} else if (ret != BEFS_OK || offset == 0) {
		befs_error(sb, "<--- %s Error", __func__);
		inode = ERR_PTR(-ENODATA);
	} else {
		inode = befs_iget(dir->i_sb, (ino_t) offset);
	}
	befs_debug(sb, "<--- %s", __func__);

	return d_splice_alias(inode, dentry);
}

static int
befs_readdir(struct file *file, struct dir_context *ctx)
{
	struct inode *inode = file_inode(file);
	struct super_block *sb = inode->i_sb;
	const befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
	befs_off_t value;
	int result;
	size_t keysize;
	char keybuf[BEFS_NAME_LEN + 1];

	befs_debug(sb, "---> %s name %pD, inode %ld, ctx->pos %lld",
		  __func__, file, inode->i_ino, ctx->pos);

	while (1) {
		result = befs_btree_read(sb, ds, ctx->pos, BEFS_NAME_LEN + 1,
					 keybuf, &keysize, &value);

		if (result == BEFS_ERR) {
			befs_debug(sb, "<--- %s ERROR", __func__);
			befs_error(sb, "IO error reading %pD (inode %lu)",
				   file, inode->i_ino);
			return -EIO;

		} else if (result == BEFS_BT_END) {
			befs_debug(sb, "<--- %s END", __func__);
			return 0;

		} else if (result == BEFS_BT_EMPTY) {
			befs_debug(sb, "<--- %s Empty directory", __func__);
			return 0;
		}

		/* Convert to NLS */
		if (BEFS_SB(sb)->nls) {
			char *nlsname;
			int nlsnamelen;

			result =
			    befs_utf2nls(sb, keybuf, keysize, &nlsname,
					 &nlsnamelen);
			if (result < 0) {
				befs_debug(sb, "<--- %s ERROR", __func__);
				return result;
			}
			if (!dir_emit(ctx, nlsname, nlsnamelen,
				      (ino_t) value, DT_UNKNOWN)) {
				kfree(nlsname);
				return 0;
			}
			kfree(nlsname);
		} else {
			if (!dir_emit(ctx, keybuf, keysize,
				      (ino_t) value, DT_UNKNOWN))
				return 0;
		}
		ctx->pos++;
	}
}

static struct inode *
befs_alloc_inode(struct super_block *sb)
{
	struct befs_inode_info *bi;

	bi = alloc_inode_sb(sb, befs_inode_cachep, GFP_KERNEL);
	if (!bi)
		return NULL;
	return &bi->vfs_inode;
}

static void befs_free_inode(struct inode *inode)
{
	kmem_cache_free(befs_inode_cachep, BEFS_I(inode));
}

static void init_once(void *foo)
{
	struct befs_inode_info *bi = (struct befs_inode_info *) foo;

	inode_init_once(&bi->vfs_inode);
}

static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
{
	struct buffer_head *bh;
	befs_inode *raw_inode;
	struct befs_sb_info *befs_sb = BEFS_SB(sb);
	struct befs_inode_info *befs_ino;
	struct inode *inode;

	befs_debug(sb, "---> %s inode = %lu", __func__, ino);

	inode = iget_locked(sb, ino);
	if (!inode)
		return ERR_PTR(-ENOMEM);
	if (!(inode->i_state & I_NEW))
		return inode;

	befs_ino = BEFS_I(inode);

	/* convert from vfs's inode number to befs's inode number */
	befs_ino->i_inode_num = blockno2iaddr(sb, inode->i_ino);

	befs_debug(sb, "  real inode number [%u, %hu, %hu]",
		   befs_ino->i_inode_num.allocation_group,
		   befs_ino->i_inode_num.start, befs_ino->i_inode_num.len);

	bh = sb_bread(sb, inode->i_ino);
	if (!bh) {
		befs_error(sb, "unable to read inode block - "
			   "inode = %lu", inode->i_ino);
		goto unacquire_none;
	}

	raw_inode = (befs_inode *) bh->b_data;

	befs_dump_inode(sb, raw_inode);

	if (befs_check_inode(sb, raw_inode, inode->i_ino) != BEFS_OK) {
		befs_error(sb, "Bad inode: %lu", inode->i_ino);
		goto unacquire_bh;
	}

	inode->i_mode = (umode_t) fs32_to_cpu(sb, raw_inode->mode);

	/*
	 * set uid and gid.  But since current BeOS is single user OS, so
	 * you can change by "uid" or "gid" options.
	 */

	inode->i_uid = befs_sb->mount_opts.use_uid ?
		befs_sb->mount_opts.uid :
		make_kuid(&init_user_ns, fs32_to_cpu(sb, raw_inode->uid));
	inode->i_gid = befs_sb->mount_opts.use_gid ?
		befs_sb->mount_opts.gid :
		make_kgid(&init_user_ns, fs32_to_cpu(sb, raw_inode->gid));

	set_nlink(inode, 1);

	/*
	 * BEFS's time is 64 bits, but current VFS is 32 bits...
	 * BEFS don't have access time. Nor inode change time. VFS
	 * doesn't have creation time.
	 * Also, the lower 16 bits of the last_modified_time and
	 * create_time are just a counter to help ensure uniqueness
	 * for indexing purposes. (PFD, page 54)
	 */

	inode->i_mtime.tv_sec =
	    fs64_to_cpu(sb, raw_inode->last_modified_time) >> 16;
	inode->i_mtime.tv_nsec = 0;   /* lower 16 bits are not a time */
	inode->i_ctime = inode->i_mtime;
	inode->i_atime = inode->i_mtime;

	befs_ino->i_inode_num = fsrun_to_cpu(sb, raw_inode->inode_num);
	befs_ino->i_parent = fsrun_to_cpu(sb, raw_inode->parent);
	befs_ino->i_attribute = fsrun_to_cpu(sb, raw_inode->attributes);
	befs_ino->i_flags = fs32_to_cpu(sb, raw_inode->flags);

	if (S_ISLNK(inode->i_mode) && !(befs_ino->i_flags & BEFS_LONG_SYMLINK)){
		inode->i_size = 0;
		inode->i_blocks = befs_sb->block_size / VFS_BLOCK_SIZE;
		strlcpy(befs_ino->i_data.symlink, raw_inode->data.symlink,
			BEFS_SYMLINK_LEN);
	} else {
		int num_blks;

		befs_ino->i_data.ds =
		    fsds_to_cpu(sb, &raw_inode->data.datastream);

		num_blks = befs_count_blocks(sb, &befs_ino->i_data.ds);
		inode->i_blocks =
		    num_blks * (befs_sb->block_size / VFS_BLOCK_SIZE);
		inode->i_size = befs_ino->i_data.ds.size;
	}

	inode->i_mapping->a_ops = &befs_aops;

	if (S_ISREG(inode->i_mode)) {
		inode->i_fop = &generic_ro_fops;
	} else if (S_ISDIR(inode->i_mode)) {
		inode->i_op = &befs_dir_inode_operations;
		inode->i_fop = &befs_dir_operations;
	} else if (S_ISLNK(inode->i_mode)) {
		if (befs_ino->i_flags & BEFS_LONG_SYMLINK) {
			inode->i_op = &page_symlink_inode_operations;
			inode_nohighmem(inode);
			inode->i_mapping->a_ops = &befs_symlink_aops;
		} else {
			inode->i_link = befs_ino->i_data.symlink;
			inode->i_op = &simple_symlink_inode_operations;
		}
	} else {
		befs_error(sb, "Inode %lu is not a regular file, "
			   "directory or symlink. THAT IS WRONG! BeFS has no "
			   "on disk special files", inode->i_ino);
		goto unacquire_bh;
	}

	brelse(bh);
	befs_debug(sb, "<--- %s", __func__);
	unlock_new_inode(inode);
	return inode;

unacquire_bh:
	brelse(bh);

unacquire_none:
	iget_failed(inode);
	befs_debug(sb, "<--- %s - Bad inode", __func__);
	return ERR_PTR(-EIO);
}

/* Initialize the inode cache. Called at fs setup.
 *
 * Taken from NFS implementation by Al Viro.
 */
static int __init
befs_init_inodecache(void)
{
	befs_inode_cachep = kmem_cache_create_usercopy("befs_inode_cache",
				sizeof(struct befs_inode_info), 0,
				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
					SLAB_ACCOUNT),
				offsetof(struct befs_inode_info,
					i_data.symlink),
				sizeof_field(struct befs_inode_info,
					i_data.symlink),
				init_once);
	if (befs_inode_cachep == NULL)
		return -ENOMEM;

	return 0;
}

/* Called at fs teardown.
 *
 * Taken from NFS implementation by Al Viro.
 */
static void
befs_destroy_inodecache(void)
{
	/*
	 * Make sure all delayed rcu free inodes are flushed before we
	 * destroy cache.
	 */
	rcu_barrier();
	kmem_cache_destroy(befs_inode_cachep);
}

/*
 * The inode of symbolic link is different to data stream.
 * The data stream become link name. Unless the LONG_SYMLINK
 * flag is set.
 */
static int befs_symlink_read_folio(struct file *unused, struct folio *folio)
{
	struct page *page = &folio->page;
	struct inode *inode = page->mapping->host;
	struct super_block *sb = inode->i_sb;
	struct befs_inode_info *befs_ino = BEFS_I(inode);
	befs_data_stream *data = &befs_ino->i_data.ds;
	befs_off_t len = data->size;
	char *link = page_address(page);

	if (len == 0 || len > PAGE_SIZE) {
		befs_error(sb, "Long symlink with illegal length");
		goto fail;
	}
	befs_debug(sb, "Follow long symlink");

	if (befs_read_lsymlink(sb, data, link, len) != len) {
		befs_error(sb, "Failed to read entire long symlink");
		goto fail;
	}
	link[len - 1] = '\0';
	SetPageUptodate(page);
	unlock_page(page);
	return 0;
fail:
	SetPageError(page);
	unlock_page(page);
	return -EIO;
}

/*
 * UTF-8 to NLS charset convert routine
 *
 * Uses uni2char() / char2uni() rather than the nls tables directly
 */
static int
befs_utf2nls(struct super_block *sb, const char *in,
	     int in_len, char **out, int *out_len)
{
	struct nls_table *nls = BEFS_SB(sb)->nls;
	int i, o;
	unicode_t uni;
	int unilen, utflen;
	char *result;
	/* The utf8->nls conversion won't make the final nls string bigger
	 * than the utf one, but if the string is pure ascii they'll have the
	 * same width and an extra char is needed to save the additional \0
	 */
	int maxlen = in_len + 1;

	befs_debug(sb, "---> %s", __func__);

	if (!nls) {
		befs_error(sb, "%s called with no NLS table loaded", __func__);
		return -EINVAL;
	}

	*out = result = kmalloc(maxlen, GFP_NOFS);
	if (!*out)
		return -ENOMEM;

	for (i = o = 0; i < in_len; i += utflen, o += unilen) {

		/* convert from UTF-8 to Unicode */
		utflen = utf8_to_utf32(&in[i], in_len - i, &uni);
		if (utflen < 0)
			goto conv_err;

		/* convert from Unicode to nls */
		if (uni > MAX_WCHAR_T)
			goto conv_err;
		unilen = nls->uni2char(uni, &result[o], in_len - o);
		if (unilen < 0)
			goto conv_err;
	}
	result[o] = '\0';
	*out_len = o;

	befs_debug(sb, "<--- %s", __func__);

	return o;

conv_err:
	befs_error(sb, "Name using character set %s contains a character that "
		   "cannot be converted to unicode.", nls->charset);
	befs_debug(sb, "<--- %s", __func__);
	kfree(result);
	return -EILSEQ;
}

/**
 * befs_nls2utf - Convert NLS string to utf8 encodeing
 * @sb: Superblock
 * @in: Input string buffer in NLS format
 * @in_len: Length of input string in bytes
 * @out: The output string in UTF-8 format
 * @out_len: Length of the output buffer
 *
 * Converts input string @in, which is in the format of the loaded NLS map,
 * into a utf8 string.
 *
 * The destination string @out is allocated by this function and the caller is
 * responsible for freeing it with kfree()
 *
 * On return, *@out_len is the length of @out in bytes.
 *
 * On success, the return value is the number of utf8 characters written to
 * the output buffer @out.
 *
 * On Failure, a negative number coresponding to the error code is returned.
 */

static int
befs_nls2utf(struct super_block *sb, const char *in,
	     int in_len, char **out, int *out_len)
{
	struct nls_table *nls = BEFS_SB(sb)->nls;
	int i, o;
	wchar_t uni;
	int unilen, utflen;
	char *result;
	/*
	 * There are nls characters that will translate to 3-chars-wide UTF-8
	 * characters, an additional byte is needed to save the final \0
	 * in special cases
	 */
	int maxlen = (3 * in_len) + 1;

	befs_debug(sb, "---> %s\n", __func__);

	if (!nls) {
		befs_error(sb, "%s called with no NLS table loaded.",
			   __func__);
		return -EINVAL;
	}

	*out = result = kmalloc(maxlen, GFP_NOFS);
	if (!*out) {
		*out_len = 0;
		return -ENOMEM;
	}

	for (i = o = 0; i < in_len; i += unilen, o += utflen) {

		/* convert from nls to unicode */
		unilen = nls->char2uni(&in[i], in_len - i, &uni);
		if (unilen < 0)
			goto conv_err;

		/* convert from unicode to UTF-8 */
		utflen = utf32_to_utf8(uni, &result[o], 3);
		if (utflen <= 0)
			goto conv_err;
	}

	result[o] = '\0';
	*out_len = o;

	befs_debug(sb, "<--- %s", __func__);

	return i;

conv_err:
	befs_error(sb, "Name using character set %s contains a character that "
		   "cannot be converted to unicode.", nls->charset);
	befs_debug(sb, "<--- %s", __func__);
	kfree(result);
	return -EILSEQ;
}

static struct inode *befs_nfs_get_inode(struct super_block *sb, uint64_t ino,
					 uint32_t generation)
{
	/* No need to handle i_generation */
	return befs_iget(sb, ino);
}

/*
 * Map a NFS file handle to a corresponding dentry
 */
static struct dentry *befs_fh_to_dentry(struct super_block *sb,
				struct fid *fid, int fh_len, int fh_type)
{
	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
				    befs_nfs_get_inode);
}

/*
 * Find the parent for a file specified by NFS handle
 */
static struct dentry *befs_fh_to_parent(struct super_block *sb,
				struct fid *fid, int fh_len, int fh_type)
{
	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
				    befs_nfs_get_inode);
}

static struct dentry *befs_get_parent(struct dentry *child)
{
	struct inode *parent;
	struct befs_inode_info *befs_ino = BEFS_I(d_inode(child));

	parent = befs_iget(child->d_sb,
			   (unsigned long)befs_ino->i_parent.start);
	if (IS_ERR(parent))
		return ERR_CAST(parent);

	return d_obtain_alias(parent);
}

enum {
	Opt_uid, Opt_gid, Opt_charset, Opt_debug, Opt_err,
};

static const match_table_t befs_tokens = {
	{Opt_uid, "uid=%d"},
	{Opt_gid, "gid=%d"},
	{Opt_charset, "iocharset=%s"},
	{Opt_debug, "debug"},
	{Opt_err, NULL}
};

static int
parse_options(char *options, struct befs_mount_options *opts)
{
	char *p;
	substring_t args[MAX_OPT_ARGS];
	int option;
	kuid_t uid;
	kgid_t gid;

	/* Initialize options */
	opts->uid = GLOBAL_ROOT_UID;
	opts->gid = GLOBAL_ROOT_GID;
	opts->use_uid = 0;
	opts->use_gid = 0;
	opts->iocharset = NULL;
	opts->debug = 0;

	if (!options)
		return 1;

	while ((p = strsep(&options, ",")) != NULL) {
		int token;

		if (!*p)
			continue;

		token = match_token(p, befs_tokens, args);
		switch (token) {
		case Opt_uid:
			if (match_int(&args[0], &option))
				return 0;
			uid = INVALID_UID;
			if (option >= 0)
				uid = make_kuid(current_user_ns(), option);
			if (!uid_valid(uid)) {
				pr_err("Invalid uid %d, "
				       "using default\n", option);
				break;
			}
			opts->uid = uid;
			opts->use_uid = 1;
			break;
		case Opt_gid:
			if (match_int(&args[0], &option))
				return 0;
			gid = INVALID_GID;
			if (option >= 0)
				gid = make_kgid(current_user_ns(), option);
			if (!gid_valid(gid)) {
				pr_err("Invalid gid %d, "
				       "using default\n", option);
				break;
			}
			opts->gid = gid;
			opts->use_gid = 1;
			break;
		case Opt_charset:
			kfree(opts->iocharset);
			opts->iocharset = match_strdup(&args[0]);
			if (!opts->iocharset) {
				pr_err("allocation failure for "
				       "iocharset string\n");
				return 0;
			}
			break;
		case Opt_debug:
			opts->debug = 1;
			break;
		default:
			pr_err("Unrecognized mount option \"%s\" "
			       "or missing value\n", p);
			return 0;
		}
	}
	return 1;
}

static int befs_show_options(struct seq_file *m, struct dentry *root)
{
	struct befs_sb_info *befs_sb = BEFS_SB(root->d_sb);
	struct befs_mount_options *opts = &befs_sb->mount_opts;

	if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
		seq_printf(m, ",uid=%u",
			   from_kuid_munged(&init_user_ns, opts->uid));
	if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
		seq_printf(m, ",gid=%u",
			   from_kgid_munged(&init_user_ns, opts->gid));
	if (opts->iocharset)
		seq_printf(m, ",charset=%s", opts->iocharset);
	if (opts->debug)
		seq_puts(m, ",debug");
	return 0;
}

/* This function has the responsibiltiy of getting the
 * filesystem ready for unmounting.
 * Basically, we free everything that we allocated in
 * befs_read_inode
 */
static void
befs_put_super(struct super_block *sb)
{
	kfree(BEFS_SB(sb)->mount_opts.iocharset);
	BEFS_SB(sb)->mount_opts.iocharset = NULL;
	unload_nls(BEFS_SB(sb)->nls);
	kfree(sb->s_fs_info);
	sb->s_fs_info = NULL;
}

/* Allocate private field of the superblock, fill it.
 *
 * Finish filling the public superblock fields
 * Make the root directory
 * Load a set of NLS translations if needed.
 */
static int
befs_fill_super(struct super_block *sb, void *data, int silent)
{
	struct buffer_head *bh;
	struct befs_sb_info *befs_sb;
	befs_super_block *disk_sb;
	struct inode *root;
	long ret = -EINVAL;
	const unsigned long sb_block = 0;
	const off_t x86_sb_off = 512;
	int blocksize;

	sb->s_fs_info = kzalloc(sizeof(*befs_sb), GFP_KERNEL);
	if (sb->s_fs_info == NULL)
		goto unacquire_none;

	befs_sb = BEFS_SB(sb);

	if (!parse_options((char *) data, &befs_sb->mount_opts)) {
		if (!silent)
			befs_error(sb, "cannot parse mount options");
		goto unacquire_priv_sbp;
	}

	befs_debug(sb, "---> %s", __func__);

	if (!sb_rdonly(sb)) {
		befs_warning(sb,
			     "No write support. Marking filesystem read-only");
		sb->s_flags |= SB_RDONLY;
	}

	/*
	 * Set dummy blocksize to read super block.
	 * Will be set to real fs blocksize later.
	 *
	 * Linux 2.4.10 and later refuse to read blocks smaller than
	 * the logical block size for the device. But we also need to read at
	 * least 1k to get the second 512 bytes of the volume.
	 */
	blocksize = sb_min_blocksize(sb, 1024);
	if (!blocksize) {
		if (!silent)
			befs_error(sb, "unable to set blocksize");
		goto unacquire_priv_sbp;
	}

	bh = sb_bread(sb, sb_block);
	if (!bh) {
		if (!silent)
			befs_error(sb, "unable to read superblock");
		goto unacquire_priv_sbp;
	}

	/* account for offset of super block on x86 */
	disk_sb = (befs_super_block *) bh->b_data;
	if ((disk_sb->magic1 == BEFS_SUPER_MAGIC1_LE) ||
	    (disk_sb->magic1 == BEFS_SUPER_MAGIC1_BE)) {
		befs_debug(sb, "Using PPC superblock location");
	} else {
		befs_debug(sb, "Using x86 superblock location");
		disk_sb =
		    (befs_super_block *) ((void *) bh->b_data + x86_sb_off);
	}

	if ((befs_load_sb(sb, disk_sb) != BEFS_OK) ||
	    (befs_check_sb(sb) != BEFS_OK))
		goto unacquire_bh;

	befs_dump_super_block(sb, disk_sb);

	brelse(bh);

	if (befs_sb->num_blocks > ~((sector_t)0)) {
		if (!silent)
			befs_error(sb, "blocks count: %llu is larger than the host can use",
					befs_sb->num_blocks);
		goto unacquire_priv_sbp;
	}

	/*
	 * set up enough so that it can read an inode
	 * Fill in kernel superblock fields from private sb
	 */
	sb->s_magic = BEFS_SUPER_MAGIC;
	/* Set real blocksize of fs */
	sb_set_blocksize(sb, (ulong) befs_sb->block_size);
	sb->s_op = &befs_sops;
	sb->s_export_op = &befs_export_operations;
	sb->s_time_min = 0;
	sb->s_time_max = 0xffffffffffffll;
	root = befs_iget(sb, iaddr2blockno(sb, &(befs_sb->root_dir)));
	if (IS_ERR(root)) {
		ret = PTR_ERR(root);
		goto unacquire_priv_sbp;
	}
	sb->s_root = d_make_root(root);
	if (!sb->s_root) {
		if (!silent)
			befs_error(sb, "get root inode failed");
		goto unacquire_priv_sbp;
	}

	/* load nls library */
	if (befs_sb->mount_opts.iocharset) {
		befs_debug(sb, "Loading nls: %s",
			   befs_sb->mount_opts.iocharset);
		befs_sb->nls = load_nls(befs_sb->mount_opts.iocharset);
		if (!befs_sb->nls) {
			befs_warning(sb, "Cannot load nls %s"
					" loading default nls",
					befs_sb->mount_opts.iocharset);
			befs_sb->nls = load_nls_default();
		}
	/* load default nls if none is specified  in mount options */
	} else {
		befs_debug(sb, "Loading default nls");
		befs_sb->nls = load_nls_default();
	}

	return 0;

unacquire_bh:
	brelse(bh);

unacquire_priv_sbp:
	kfree(befs_sb->mount_opts.iocharset);
	kfree(sb->s_fs_info);
	sb->s_fs_info = NULL;

unacquire_none:
	return ret;
}

static int
befs_remount(struct super_block *sb, int *flags, char *data)
{
	sync_filesystem(sb);
	if (!(*flags & SB_RDONLY))
		return -EINVAL;
	return 0;
}

static int
befs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
	struct super_block *sb = dentry->d_sb;
	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);

	befs_debug(sb, "---> %s", __func__);

	buf->f_type = BEFS_SUPER_MAGIC;
	buf->f_bsize = sb->s_blocksize;
	buf->f_blocks = BEFS_SB(sb)->num_blocks;
	buf->f_bfree = BEFS_SB(sb)->num_blocks - BEFS_SB(sb)->used_blocks;
	buf->f_bavail = buf->f_bfree;
	buf->f_files = 0;	/* UNKNOWN */
	buf->f_ffree = 0;	/* UNKNOWN */
	buf->f_fsid = u64_to_fsid(id);
	buf->f_namelen = BEFS_NAME_LEN;

	befs_debug(sb, "<--- %s", __func__);

	return 0;
}

static struct dentry *
befs_mount(struct file_system_type *fs_type, int flags, const char *dev_name,
	    void *data)
{
	return mount_bdev(fs_type, flags, dev_name, data, befs_fill_super);
}

static struct file_system_type befs_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "befs",
	.mount		= befs_mount,
	.kill_sb	= kill_block_super,
	.fs_flags	= FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("befs");

static int __init
init_befs_fs(void)
{
	int err;

	pr_info("version: %s\n", BEFS_VERSION);

	err = befs_init_inodecache();
	if (err)
		goto unacquire_none;

	err = register_filesystem(&befs_fs_type);
	if (err)
		goto unacquire_inodecache;

	return 0;

unacquire_inodecache:
	befs_destroy_inodecache();

unacquire_none:
	return err;
}

static void __exit
exit_befs_fs(void)
{
	befs_destroy_inodecache();

	unregister_filesystem(&befs_fs_type);
}

/*
 * Macros that typecheck the init and exit functions,
 * ensures that they are called at init and cleanup,
 * and eliminates warnings about unused functions.
 */
module_init(init_befs_fs)
module_exit(exit_befs_fs)