summaryrefslogtreecommitdiff
path: root/libparted/fs/r/fat/resize.c
blob: 78dede4313d209fb91428ce42660113d480dc1f6 (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
/*
    libparted
    Copyright (C) 1998-2000, 2007-2014, 2019-2023 Free Software Foundation,
    Inc.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <config.h>
#include "fat.h"
#include "traverse.h"
#include "count.h"
#include "fatio.h"
#include "calc.h"

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <stdarg.h>
#include <string.h>

#ifndef DISCOVER_ONLY

/* Recursively builds (i.e. makes consistent) the duplicated directory tree
 * (leaving the original directory tree in tact)
 */
static int
fat_construct_directory (FatOpContext* ctx, FatTraverseInfo* trav_info)
{
	FatTraverseInfo*	sub_dir_info;
	FatDirEntry*		dir_entry;
	FatCluster		old_first_cluster;

	while ( (dir_entry = fat_traverse_next_dir_entry (trav_info)) ) {
		if (fat_dir_entry_is_null_term (dir_entry))
			break;
		if (!fat_dir_entry_has_first_cluster (dir_entry, ctx->old_fs))
			continue;

		fat_traverse_mark_dirty (trav_info);

		old_first_cluster = fat_dir_entry_get_first_cluster (dir_entry,
						ctx->old_fs);
		fat_dir_entry_set_first_cluster (dir_entry, ctx->new_fs,
			fat_op_context_map_cluster (ctx, old_first_cluster));

		if (fat_dir_entry_is_directory (dir_entry)
				&& dir_entry->name [0] != '.') {
			sub_dir_info
				= fat_traverse_directory (trav_info, dir_entry);
			if (!sub_dir_info)
				return 0;
			if (!fat_construct_directory (ctx, sub_dir_info))
				return 0;
		}
	}
	/* remove "stale" entries at the end */
	while ((dir_entry = fat_traverse_next_dir_entry (trav_info))) {
		memset (dir_entry, 0, sizeof (FatDirEntry));
		fat_traverse_mark_dirty (trav_info);
	}
	fat_traverse_complete (trav_info);
	return 1;
}

static int
duplicate_legacy_root_dir (FatOpContext* ctx)
{
	FatSpecific*		old_fs_info = FAT_SPECIFIC (ctx->old_fs);
	FatSpecific*		new_fs_info = FAT_SPECIFIC (ctx->new_fs);

	PED_ASSERT (old_fs_info->root_dir_sector_count
			== new_fs_info->root_dir_sector_count);

	if (!ped_geometry_read (ctx->old_fs->geom, old_fs_info->buffer,
				old_fs_info->root_dir_offset,
				old_fs_info->root_dir_sector_count))
		return 0;

	if (!ped_geometry_write (ctx->new_fs->geom, old_fs_info->buffer,
				 new_fs_info->root_dir_offset,
				 new_fs_info->root_dir_sector_count))
		return 0;

	return 1;
}

/*
    Constructs the new directory tree for legacy (FAT16) file systems.
*/
static int
fat_construct_legacy_root (FatOpContext* ctx)
{
	FatTraverseInfo*	trav_info;

	if (!duplicate_legacy_root_dir (ctx))
		return 0;
	trav_info = fat_traverse_begin (ctx->new_fs, FAT_ROOT, "\\");
	return fat_construct_directory (ctx, trav_info);
}

/*
    Constructs the new directory tree for new (FAT32) file systems.
*/
static int
fat_construct_root (FatOpContext* ctx)
{
	FatSpecific*		new_fs_info = FAT_SPECIFIC (ctx->new_fs);
	FatTraverseInfo*	trav_info;

	trav_info = fat_traverse_begin (ctx->new_fs, new_fs_info->root_cluster,
					"\\");
	fat_construct_directory (ctx, trav_info);
	return 1;
}

/* Converts the root directory between FAT16 and FAT32.  NOTE: this code
 * can also do no conversion.  I'm leaving fat_construct_directory(), because
 * it's really pretty :-)  It also leaves a higher chance of deleted file
 * recovery, because it doesn't remove redundant entries.  (We do this here,
 * because brain-damaged FAT16 has an arbitary limit on root directory entries,
 * so we save room)
 */
static int
fat_convert_directory (FatOpContext* ctx, FatTraverseInfo* old_trav,
		       FatTraverseInfo* new_trav)
{
	FatTraverseInfo*	sub_old_dir_trav;
	FatTraverseInfo*	sub_new_dir_trav;
	FatDirEntry*		new_dir_entry;
	FatDirEntry*		old_dir_entry;
	FatCluster		old_first_cluster;

	while ( (old_dir_entry = fat_traverse_next_dir_entry (old_trav)) ) {
		if (fat_dir_entry_is_null_term (old_dir_entry))
			break;
		if (!fat_dir_entry_is_active (old_dir_entry))
			continue;

		new_dir_entry = fat_traverse_next_dir_entry (new_trav);
		if (!new_dir_entry) {
			return ped_exception_throw (PED_EXCEPTION_ERROR,
				PED_EXCEPTION_IGNORE_CANCEL,
				_("There's not enough room in the root "
				  "directory for all of the files.  Either "
				  "cancel, or ignore to lose the files."))
					== PED_EXCEPTION_IGNORE;
		}

		*new_dir_entry = *old_dir_entry;
		fat_traverse_mark_dirty (new_trav);

		if (!fat_dir_entry_has_first_cluster (old_dir_entry,
						      ctx->old_fs))
			continue;

		old_first_cluster = fat_dir_entry_get_first_cluster (
						old_dir_entry, ctx->old_fs);
		fat_dir_entry_set_first_cluster (new_dir_entry, ctx->new_fs,
			fat_op_context_map_cluster (ctx, old_first_cluster));

		if (fat_dir_entry_is_directory (old_dir_entry)
				&& old_dir_entry->name [0] != '.') {
			sub_old_dir_trav
			    = fat_traverse_directory (old_trav, old_dir_entry);
			if (!sub_old_dir_trav) return 0;
			sub_new_dir_trav
			    = fat_traverse_directory (new_trav, new_dir_entry);
			if (!sub_new_dir_trav) {
				fat_traverse_complete (sub_old_dir_trav);
				return 0;
			}

			if (!fat_convert_directory (ctx, sub_old_dir_trav,
						    sub_new_dir_trav))
				return 0;
		}
	}

	/* remove "stale" entries at the end, just in case there is some
	 * overlap
	 */
	while ((new_dir_entry = fat_traverse_next_dir_entry (new_trav))) {
		memset (new_dir_entry, 0, sizeof (FatDirEntry));
		fat_traverse_mark_dirty (new_trav);
	}

	fat_traverse_complete (old_trav);
	fat_traverse_complete (new_trav);
	return 1;
}

static void
clear_cluster (PedFileSystem* fs, FatCluster cluster)
{
	FatSpecific*		fs_info = FAT_SPECIFIC (fs);

	memset (fs_info->buffer, 0, fs_info->cluster_size);
	fat_write_cluster (fs, fs_info->buffer, cluster);
}

/* This MUST be called BEFORE the fat_construct_new_fat(), because cluster
 * allocation depend on the old FAT.  The reason is, old clusters may
 * still be needed during the resize, (particularly clusters in the directory
 * tree) even if they will be discarded later.
 */
static int
alloc_root_dir (FatOpContext* ctx)
{
	FatSpecific*		old_fs_info = FAT_SPECIFIC (ctx->old_fs);
	FatSpecific*		new_fs_info = FAT_SPECIFIC (ctx->new_fs);
	FatCluster		i;
	FatCluster		cluster;
	FatCluster		cluster_count;

	PED_ASSERT (new_fs_info->fat_type == FAT_TYPE_FAT32);

	cluster_count = ped_div_round_up (
			   PED_MAX (16, old_fs_info->root_dir_sector_count),
			   new_fs_info->cluster_sectors);

	for (i = 0; i < cluster_count; i++) {
		cluster = fat_table_alloc_check_cluster (new_fs_info->fat,
							 ctx->new_fs);
		if (!cluster)
			return 0;
		ctx->new_root_dir [i] = cluster;
		clear_cluster (ctx->new_fs, cluster);
	}
	ctx->new_root_dir [i] = 0;
	new_fs_info->root_cluster = ctx->new_root_dir [0];
	return 1;
}

/* when converting FAT32 -> FAT16
 * fat_duplicate clusters() duplicated the root directory unnecessarily.
 * Let's free it.
 *
 * This must be called AFTER fat_construct_new_fat().  (otherwise, our
 * changes just get overwritten)
 */
static int
free_root_dir (FatOpContext* ctx)
{
	FatSpecific*		old_fs_info = FAT_SPECIFIC (ctx->old_fs);
	FatSpecific*		new_fs_info = FAT_SPECIFIC (ctx->new_fs);
	FatCluster		old_cluster;
	FatFragment		i;

	PED_ASSERT (old_fs_info->fat_type == FAT_TYPE_FAT32);
	PED_ASSERT (new_fs_info->fat_type == FAT_TYPE_FAT16);

	for (old_cluster = old_fs_info->root_cluster;
	     !fat_table_is_eof (old_fs_info->fat, old_cluster);
	     old_cluster = fat_table_get (old_fs_info->fat, old_cluster)) {
		FatFragment old_frag;
		old_frag = fat_cluster_to_frag (ctx->old_fs, old_cluster);
		for (i = 0; i < new_fs_info->cluster_frags; i++) {
			FatFragment new_frag;
			FatCluster new_clst;
			new_frag = fat_op_context_map_fragment (ctx,
								old_frag + i);
			new_clst = fat_frag_to_cluster (ctx->old_fs, new_frag);
			if (!fat_table_set_avail (new_fs_info->fat, new_clst))
				return 0;
		}
	}

	return 1;
}

static int
fat_clear_root_dir (PedFileSystem* fs)
{
	FatSpecific*	fs_info = FAT_SPECIFIC (fs);
	int		i;

	PED_ASSERT (fs_info->fat_type == FAT_TYPE_FAT16);
	PED_ASSERT (fs_info->root_dir_sector_count);

	memset (fs_info->buffer, 0, 512);

	for (i = 0; i < fs_info->root_dir_sector_count; i++) {
		if (!ped_geometry_write (fs->geom, fs_info->buffer,
					 fs_info->root_dir_offset + i, 1)) {
			if (ped_exception_throw (PED_EXCEPTION_ERROR,
				PED_EXCEPTION_IGNORE_CANCEL,
				_("Error writing to the root directory."))
					== PED_EXCEPTION_CANCEL)
				return 0;
		}
	}
	return 1;
}

static int
fat_construct_converted_tree (FatOpContext* ctx)
{
	FatSpecific*		old_fs_info = FAT_SPECIFIC (ctx->old_fs);
	FatSpecific*		new_fs_info = FAT_SPECIFIC (ctx->new_fs);
	FatTraverseInfo*	old_trav_info;
	FatTraverseInfo*	new_trav_info;

	if (new_fs_info->fat_type == FAT_TYPE_FAT32) {
		new_trav_info = fat_traverse_begin (ctx->new_fs,
					    new_fs_info->root_cluster, "\\");
		if (!new_trav_info) return 0;
		old_trav_info = fat_traverse_begin (ctx->old_fs, FAT_ROOT,
						    "\\");
	} else {
		fat_clear_root_dir (ctx->new_fs);
		new_trav_info = fat_traverse_begin (ctx->new_fs, FAT_ROOT,
						    "\\");
		if (!new_trav_info) return 0;
		old_trav_info = fat_traverse_begin (ctx->old_fs,
					    old_fs_info->root_cluster, "\\");
	}
	if (!old_trav_info) {
		fat_traverse_complete (new_trav_info);
		return 0;
	}
	if (!fat_convert_directory (ctx, old_trav_info, new_trav_info))
		return 0;
	return 1;
}

/*
    Constructs the new directory tree to match the new file locations.
*/
static int
fat_construct_dir_tree (FatOpContext* ctx)
{
	FatSpecific*		new_fs_info = FAT_SPECIFIC (ctx->new_fs);
	FatSpecific*		old_fs_info = FAT_SPECIFIC (ctx->old_fs);

	if (new_fs_info->fat_type == old_fs_info->fat_type) {
		switch (old_fs_info->fat_type) {
                        case FAT_TYPE_FAT12:
                        PED_ASSERT (0);
                        break;

			case FAT_TYPE_FAT16:
			return fat_construct_legacy_root (ctx);

			case FAT_TYPE_FAT32:
			return fat_construct_root (ctx);
		}
	} else {
		return fat_construct_converted_tree (ctx);
	}

	return 0;
}

static FatFragment
_get_next_old_frag (FatOpContext* ctx, FatFragment frag)
{
	FatSpecific*	old_fs_info = FAT_SPECIFIC (ctx->old_fs);
	FatCluster	cluster;
	FatCluster	next_cluster;

	if ((frag + 1) % old_fs_info->cluster_frags != 0) {
		if (fat_is_fragment_active (ctx->old_fs, frag + 1))
			return frag + 1;
		else
			return -1;
	} else {
		cluster = fat_frag_to_cluster (ctx->old_fs, frag);
		next_cluster = fat_table_get (old_fs_info->fat, cluster);

		if (fat_table_is_eof (old_fs_info->fat, next_cluster))
			return -1;
		else
			return fat_cluster_to_frag (ctx->old_fs, next_cluster);
	}
}

/*
    Constructs the new fat for the resized file system.
*/
static int
fat_construct_new_fat (FatOpContext* ctx)
{
	FatSpecific*	old_fs_info = FAT_SPECIFIC (ctx->old_fs);
	FatSpecific*	new_fs_info = FAT_SPECIFIC (ctx->new_fs);
	FatFragment	old_frag;
	FatCluster	new_cluster;
	FatFragment	new_frag;
	FatFragment	old_next_frag;
	FatFragment	new_next_frag;
	FatCluster	new_next_cluster;
	FatClusterFlag	flag;
	int		i;

	fat_table_clear (new_fs_info->fat);
	if (!fat_table_set_cluster_count (new_fs_info->fat,
					  new_fs_info->cluster_count))
		return 0;

	for (old_frag = 0; old_frag < old_fs_info->frag_count; old_frag++) {
		flag = fat_get_fragment_flag (ctx->old_fs, old_frag);
		if (flag == FAT_FLAG_FREE)
			continue;
		if (flag == FAT_FLAG_BAD) {
			new_frag = fat_op_context_map_static_fragment (
						ctx, old_frag);
			if (new_frag == -1)
				continue;
			new_cluster = fat_frag_to_cluster (ctx->new_fs,
							   new_frag);
			fat_table_set_bad (new_fs_info->fat, new_cluster);
			continue;
		}

		new_frag = fat_op_context_map_fragment (ctx, old_frag);
		new_cluster = fat_frag_to_cluster (ctx->new_fs, new_frag);

		old_next_frag = _get_next_old_frag (ctx, old_frag);
		if (old_next_frag == -1) {
			fat_table_set_eof (new_fs_info->fat, new_cluster);
			continue;
		}

		new_next_frag = fat_op_context_map_fragment (ctx,
							     old_next_frag);
		PED_ASSERT (new_next_frag != -1);

		new_next_cluster = fat_frag_to_cluster (ctx->new_fs,
							new_next_frag);
		PED_ASSERT (new_next_cluster != new_cluster);

		fat_table_set (new_fs_info->fat, new_cluster, new_next_cluster);
	}

	if (old_fs_info->fat_type == FAT_TYPE_FAT32
	    && new_fs_info->fat_type == FAT_TYPE_FAT32) {
		new_fs_info->root_cluster
			= fat_op_context_map_cluster (ctx,
					old_fs_info->root_cluster);
	}

	if (old_fs_info->fat_type == FAT_TYPE_FAT16
	    && new_fs_info->fat_type == FAT_TYPE_FAT32) {
		for (i=0; ctx->new_root_dir[i+1]; i++) {
			fat_table_set (new_fs_info->fat,
				       ctx->new_root_dir[i],
				       ctx->new_root_dir[i+1]);
		}
		fat_table_set_eof (new_fs_info->fat, ctx->new_root_dir[i]);
	}

	return 1;
}

static int
ask_type (PedFileSystem* fs, int fat16_ok, int fat32_ok, FatType* out_fat_type)
{
	FatSpecific*		fs_info = FAT_SPECIFIC (fs);
	PedExceptionOption	status;
	const char*		fat16_msg;
	const char*		fat32_msg;

	if (fs_info->fat_type == FAT_TYPE_FAT16)
		fat16_msg = _("If you leave your file system as FAT16, "
			      "then you will have no problems.");
	else
		fat16_msg = _("If you convert to FAT16, and MS Windows "
			      "is installed on this partition, then "
			      "you must re-install the MS Windows boot "
			      "loader.  If you want to do this, you "
			      "should consult the Parted manual (or "
			      "your distribution's manual).");

	if (fs_info->fat_type == FAT_TYPE_FAT32)
		fat32_msg = _("If you leave your file system as FAT32, "
			      "then you will not introduce any new "
			      "problems.");
	else
		fat32_msg = _("If you convert to FAT32, and MS Windows "
			      "is installed on this partition, then "
			      "you must re-install the MS Windows boot "
			      "loader.  If you want to do this, you "
			      "should consult the Parted manual (or "
			      "your distribution's manual).  Also, "
			      "converting to FAT32 will make the file "
			      "system unreadable by MS DOS, MS Windows "
			      "95a, and MS Windows NT.");

	if (fat16_ok && fat32_ok) {
		status = ped_exception_throw (
			 PED_EXCEPTION_INFORMATION,
			 PED_EXCEPTION_YES_NO_CANCEL,
			 _("%s  %s  %s"),
			 _("Would you like to use FAT32?"),
			 fat16_msg,
			 fat32_msg);

		switch (status) {
		case PED_EXCEPTION_YES:
			*out_fat_type = FAT_TYPE_FAT32;
			return 1;

		case PED_EXCEPTION_NO:
			*out_fat_type = FAT_TYPE_FAT16;
			return 1;

		case PED_EXCEPTION_UNHANDLED:
			*out_fat_type = fs_info->fat_type;
			return 1;

		case PED_EXCEPTION_CANCEL:
			return 0;

                default:
                        PED_ASSERT (0);
                        break;
		}
	}

	if (fat16_ok) {
		if (fs_info->fat_type != FAT_TYPE_FAT16) {
			status = ped_exception_throw (
				PED_EXCEPTION_WARNING,
				PED_EXCEPTION_OK_CANCEL,
				_("%s  %s"),
				_("The file system can only be resized to this "
				  "size by converting to FAT16."),
				fat16_msg);
			if (status == PED_EXCEPTION_CANCEL)
				return 0;
		}
		*out_fat_type = FAT_TYPE_FAT16;
		return 1;
	}

	if (fat32_ok) {
		if (fs_info->fat_type != FAT_TYPE_FAT32) {
			status = ped_exception_throw (
				PED_EXCEPTION_WARNING,
				PED_EXCEPTION_OK_CANCEL,
				_("%s  %s"),
				_("The file system can only be resized to this "
				  "size by converting to FAT32."),
				fat32_msg);
			if (status == PED_EXCEPTION_CANCEL)
				return 0;
		}
		*out_fat_type = FAT_TYPE_FAT32;
		return 1;
	}

	ped_exception_throw (
		PED_EXCEPTION_NO_FEATURE,
		PED_EXCEPTION_CANCEL,
		_("GNU Parted cannot resize this partition to this size.  "
		  "We're working on it!"));

	return 0;
}

/*  For resize operations: determine if the file system must be FAT16 or FAT32,
 *  or either.  If the new file system must be FAT32, then query for
 *  confirmation.  If either file system can be used, query for which one.
 */
static int
get_fat_type (PedFileSystem* fs, const PedGeometry* new_geom,
	      FatType* out_fat_type)
{
	FatSpecific*		fs_info = FAT_SPECIFIC (fs);
	PedSector		fat16_cluster_sectors;
	PedSector		fat32_cluster_sectors;
	FatCluster		dummy_cluster_count;
	PedSector		dummy_fat_sectors;
	int			fat16_ok;
	int			fat32_ok;

	fat16_ok = fat_calc_resize_sizes (
				    new_geom,
				    fs_info->cluster_sectors,
				    FAT_TYPE_FAT16,
				    fs_info->root_dir_sector_count,
				    fs_info->cluster_sectors,
				    &fat16_cluster_sectors,
				    &dummy_cluster_count,
				    &dummy_fat_sectors);

	fat32_ok = fat_calc_resize_sizes (
				    new_geom,
				    fs_info->cluster_sectors,
				    FAT_TYPE_FAT32,
				    fs_info->root_dir_sector_count,
				    fs_info->cluster_sectors,
				    &fat32_cluster_sectors,
				    &dummy_cluster_count,
				    &dummy_fat_sectors);

	return ask_type (fs, fat16_ok, fat32_ok, out_fat_type);
}

/*  Creates the PedFileSystem struct for the new resized file system, and
    sticks it in a FatOpContext.  At the end of the process, the original
    (ctx->old_fs) is destroyed, and replaced with the new one (ctx->new_fs).
 */
static FatOpContext*
create_resize_context (PedFileSystem* fs, const PedGeometry* new_geom)
{
	FatSpecific*	fs_info = FAT_SPECIFIC (fs);
	FatSpecific*	new_fs_info;
	PedFileSystem*	new_fs;
	PedSector	new_cluster_sectors;
	FatCluster	new_cluster_count;
	PedSector	new_fat_sectors;
	FatType		new_fat_type;
	PedSector	root_dir_sector_count;
	FatOpContext*	context;

	/* hypothetical number of root dir sectors, if we end up using
	 * FAT16
	 */
	if (fs_info->root_dir_sector_count)
		root_dir_sector_count = fs_info->root_dir_sector_count;
	else
		root_dir_sector_count = FAT_ROOT_DIR_ENTRY_COUNT
						* sizeof (FatDirEntry) / 512;

	if (!get_fat_type (fs, new_geom, &new_fat_type))
		return 0;

	fat_calc_resize_sizes (new_geom, fs_info->cluster_sectors, new_fat_type,
		root_dir_sector_count, fs_info->cluster_sectors,
		&new_cluster_sectors, &new_cluster_count, &new_fat_sectors);

	if (!fat_check_resize_geometry (fs, new_geom, new_cluster_sectors,
				        new_cluster_count))
		goto error;

	new_fs = fat_alloc (new_geom);
	if (!new_fs)
		goto error;

	new_fs_info = FAT_SPECIFIC (new_fs);
	if (!new_fs_info)
		goto error_free_new_fs;

/* preserve boot code, etc. */
	new_fs_info->boot_sector = ped_malloc (new_geom->dev->sector_size);
	memcpy (new_fs_info->boot_sector, fs_info->boot_sector,
		new_geom->dev->sector_size);
	new_fs_info->info_sector = NULL;
	if (fs_info->fat_type == FAT_TYPE_FAT32)
	{
		PED_ASSERT (fs_info->info_sector != NULL);
		new_fs_info->info_sector =
			ped_malloc (new_geom->dev->sector_size);
		memcpy (new_fs_info->info_sector, fs_info->info_sector,
			new_geom->dev->sector_size);
	}

	new_fs_info->logical_sector_size = fs_info->logical_sector_size;
	new_fs_info->sector_count = new_geom->length;

	new_fs_info->sectors_per_track = fs_info->sectors_per_track;
	new_fs_info->heads = fs_info->heads;

	new_fs_info->cluster_size = new_cluster_sectors * 512;
	new_fs_info->cluster_sectors = new_cluster_sectors;
	new_fs_info->cluster_count = new_cluster_count;
	new_fs_info->dir_entries_per_cluster = fs_info->dir_entries_per_cluster;

	new_fs_info->fat_type = new_fat_type;
	new_fs_info->fat_table_count = 2;
	new_fs_info->fat_sectors = new_fat_sectors;

	/* what about copying? */
	new_fs_info->serial_number = fs_info->serial_number;

	if (new_fs_info->fat_type == FAT_TYPE_FAT32) {
		new_fs_info->info_sector_offset	= 1;
		new_fs_info->boot_sector_backup_offset = 6;

		new_fs_info->root_dir_offset = 0;
		new_fs_info->root_dir_entry_count = 0;
		new_fs_info->root_dir_sector_count = 0;

		/* we add calc_align_sectors to push the cluster_offset
		   forward, to keep the clusters aligned between the new
		   and old file systems
		 */
		new_fs_info->fat_offset
			= fat_min_reserved_sector_count (FAT_TYPE_FAT32)
			  + fat_calc_align_sectors (new_fs, fs);

		new_fs_info->cluster_offset
			= new_fs_info->fat_offset
			  + 2 * new_fs_info->fat_sectors;
	} else {
		new_fs_info->root_dir_sector_count = root_dir_sector_count;
		new_fs_info->root_dir_entry_count
			= root_dir_sector_count * 512 / sizeof (FatDirEntry);

		new_fs_info->fat_offset
			= fat_min_reserved_sector_count (FAT_TYPE_FAT16)
			  + fat_calc_align_sectors (new_fs, fs);

		new_fs_info->root_dir_offset = new_fs_info->fat_offset
					       + 2 * new_fs_info->fat_sectors;

		new_fs_info->cluster_offset = new_fs_info->root_dir_offset
					  + new_fs_info->root_dir_sector_count;
	}

	new_fs_info->total_dir_clusters = fs_info->total_dir_clusters;

	context = fat_op_context_new (new_fs, fs);
	if (!context)
		goto error_free_new_fs_info;

	if (!fat_op_context_create_initial_fat (context))
		goto error_free_context;

	if (!fat_alloc_buffers (new_fs))
		goto error_free_fat;

	return context;

error_free_fat:
	fat_table_destroy (new_fs_info->fat);
error_free_context:
	free (context);
error_free_new_fs_info:
	free (new_fs_info);
error_free_new_fs:
	free (new_fs);
error:
	return NULL;
}

static int
resize_context_assimilate (FatOpContext* ctx)
{
	FatSpecific*	old_fs_info = FAT_SPECIFIC (ctx->old_fs);
	FatSpecific*	new_fs_info = FAT_SPECIFIC (ctx->new_fs);

	fat_free_buffers (ctx->old_fs);
	fat_table_destroy (old_fs_info->fat);
	free (old_fs_info);
	ped_geometry_destroy (ctx->old_fs->geom);

	ctx->old_fs->type_specific = ctx->new_fs->type_specific;
	ctx->old_fs->geom = ctx->new_fs->geom;
	ctx->old_fs->type = (new_fs_info->fat_type == FAT_TYPE_FAT16)
				? &fat16_type
			       	: &fat32_type;

	free (ctx->new_fs);

	fat_op_context_destroy (ctx);

	return 1;
}

static int
resize_context_abort (FatOpContext* ctx)
{
	FatSpecific*	new_fs_info = FAT_SPECIFIC (ctx->new_fs);

	fat_free_buffers (ctx->new_fs);
	fat_table_destroy (new_fs_info->fat);
	free (new_fs_info);
	ped_geometry_destroy (ctx->new_fs->geom);
	free (ctx->new_fs);

	fat_op_context_destroy (ctx);

	return 1;
}

/* copies the "hidden" sectors, between the boot sector and the FAT.  Required,
 * for the Windows 98 FAT32 boot loader
 */
int
_copy_hidden_sectors (FatOpContext* ctx)
{
	FatSpecific*    old_fs_info = FAT_SPECIFIC (ctx->old_fs);
	FatSpecific*    new_fs_info = FAT_SPECIFIC (ctx->new_fs);
	PedSector       first = 1;
	PedSector       last;
	PedSector       count;

	/* nothing to copy for FAT16 */
	if (old_fs_info->fat_type == FAT_TYPE_FAT16
			|| new_fs_info->fat_type == FAT_TYPE_FAT16)
		return 1;

	last = PED_MIN (old_fs_info->fat_offset, new_fs_info->fat_offset) - 1;
	count = last - first + 1;

	PED_ASSERT (count < BUFFER_SIZE);

	if (!ped_geometry_read (ctx->old_fs->geom, old_fs_info->buffer,
				first, count))
		return 0;
	if (!ped_geometry_write (ctx->new_fs->geom, old_fs_info->buffer,
				 first, count))
		return 0;
	return 1;
}

int
fat_resize (PedFileSystem* fs, PedGeometry* geom, PedTimer* timer)
{
	FatSpecific*	fs_info = FAT_SPECIFIC (fs);
	FatSpecific*	new_fs_info;
	FatOpContext*	ctx;
	PedFileSystem*	new_fs;

	ctx = create_resize_context (fs, geom);
	if (!ctx)
		goto error;
	new_fs = ctx->new_fs;
	new_fs_info = FAT_SPECIFIC (new_fs);

	if (!fat_duplicate_clusters (ctx, timer))
		goto error_abort_ctx;
	if (fs_info->fat_type == FAT_TYPE_FAT16
			&& new_fs_info->fat_type == FAT_TYPE_FAT32) {
		if (!alloc_root_dir (ctx))
			goto error_abort_ctx;
	}
	if (!fat_construct_new_fat (ctx))
		goto error_abort_ctx;
	if (fs_info->fat_type == FAT_TYPE_FAT32
			&& new_fs_info->fat_type == FAT_TYPE_FAT16) {
		if (!free_root_dir (ctx))
			goto error_abort_ctx;
	}
	if (!fat_construct_dir_tree (ctx))
		goto error_abort_ctx;
	if (!fat_table_write_all (new_fs_info->fat, new_fs))
		goto error_abort_ctx;

	_copy_hidden_sectors (ctx);
	fat_boot_sector_generate (&new_fs_info->boot_sector, new_fs);
	fat_boot_sector_write (new_fs_info->boot_sector, new_fs);
	if (new_fs_info->fat_type == FAT_TYPE_FAT32) {
		fat_info_sector_generate (&new_fs_info->info_sector, new_fs);
		fat_info_sector_write (new_fs_info->info_sector, new_fs);
	}

	if (!resize_context_assimilate (ctx))
		goto error;

	return 1;

error_abort_ctx:
	resize_context_abort (ctx);
error:
	return 0;
}

#endif /* !DISCOVER_ONLY */