aboutsummaryrefslogtreecommitdiff
path: root/fs/exfat/balloc.c
blob: a987919686c0d4d339ce71d11887d9510280df77 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
 */

#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>

#include "exfat_raw.h"
#include "exfat_fs.h"

static const unsigned char free_bit[] = {
	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/*  0 ~  19*/
	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3,/* 20 ~  39*/
	0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/* 40 ~  59*/
	0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/* 60 ~  79*/
	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2,/* 80 ~  99*/
	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3,/*100 ~ 119*/
	0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*120 ~ 139*/
	0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,/*140 ~ 159*/
	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/*160 ~ 179*/
	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3,/*180 ~ 199*/
	0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*200 ~ 219*/
	0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/*220 ~ 239*/
	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0                /*240 ~ 254*/
};

static const unsigned char used_bit[] = {
	0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3,/*  0 ~  19*/
	2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4,/* 20 ~  39*/
	2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5,/* 40 ~  59*/
	4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,/* 60 ~  79*/
	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4,/* 80 ~  99*/
	3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,/*100 ~ 119*/
	4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4,/*120 ~ 139*/
	3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,/*140 ~ 159*/
	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5,/*160 ~ 179*/
	4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4, 5,/*180 ~ 199*/
	3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6,/*200 ~ 219*/
	5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,/*220 ~ 239*/
	4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8             /*240 ~ 255*/
};

/*
 *  Allocation Bitmap Management Functions
 */
static int exfat_allocate_bitmap(struct super_block *sb,
		struct exfat_dentry *ep)
{
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	long long map_size;
	unsigned int i, need_map_size;
	sector_t sector;

	sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu);
	map_size = le64_to_cpu(ep->dentry.bitmap.size);
	need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE)
		+ 1;
	if (need_map_size != map_size) {
		exfat_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)",
			  need_map_size, map_size);
		/*
		 * Only allowed when bogus allocation
		 * bitmap size is large
		 */
		if (need_map_size > map_size)
			return -EIO;
	}
	sbi->map_sectors = ((need_map_size - 1) >>
			(sb->s_blocksize_bits)) + 1;
	sbi->vol_amap = kmalloc_array(sbi->map_sectors,
				sizeof(struct buffer_head *), GFP_KERNEL);
	if (!sbi->vol_amap)
		return -ENOMEM;

	sector = exfat_cluster_to_sector(sbi, sbi->map_clu);
	for (i = 0; i < sbi->map_sectors; i++) {
		sbi->vol_amap[i] = sb_bread(sb, sector + i);
		if (!sbi->vol_amap[i]) {
			/* release all buffers and free vol_amap */
			int j = 0;

			while (j < i)
				brelse(sbi->vol_amap[j++]);

			kfree(sbi->vol_amap);
			sbi->vol_amap = NULL;
			return -EIO;
		}
	}

	return 0;
}

int exfat_load_bitmap(struct super_block *sb)
{
	unsigned int i, type;
	struct exfat_chain clu;
	struct exfat_sb_info *sbi = EXFAT_SB(sb);

	exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
	while (clu.dir != EXFAT_EOF_CLUSTER) {
		for (i = 0; i < sbi->dentries_per_clu; i++) {
			struct exfat_dentry *ep;
			struct buffer_head *bh;

			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
			if (!ep)
				return -EIO;

			type = exfat_get_entry_type(ep);
			if (type == TYPE_UNUSED)
				break;
			if (type != TYPE_BITMAP)
				continue;
			if (ep->dentry.bitmap.flags == 0x0) {
				int err;

				err = exfat_allocate_bitmap(sb, ep);
				brelse(bh);
				return err;
			}
			brelse(bh);
		}

		if (exfat_get_next_cluster(sb, &clu.dir))
			return -EIO;
	}

	return -EINVAL;
}

void exfat_free_bitmap(struct exfat_sb_info *sbi)
{
	int i;

	for (i = 0; i < sbi->map_sectors; i++)
		__brelse(sbi->vol_amap[i]);

	kfree(sbi->vol_amap);
}

/*
 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
 * the cluster heap.
 */
int exfat_set_bitmap(struct inode *inode, unsigned int clu)
{
	int i, b;
	unsigned int ent_idx;
	struct super_block *sb = inode->i_sb;
	struct exfat_sb_info *sbi = EXFAT_SB(sb);

	WARN_ON(clu < EXFAT_FIRST_CLUSTER);
	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);

	set_bit_le(b, sbi->vol_amap[i]->b_data);
	exfat_update_bh(sbi->vol_amap[i], IS_DIRSYNC(inode));
	return 0;
}

/*
 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
 * the cluster heap.
 */
void exfat_clear_bitmap(struct inode *inode, unsigned int clu)
{
	int i, b;
	unsigned int ent_idx;
	struct super_block *sb = inode->i_sb;
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	struct exfat_mount_options *opts = &sbi->options;

	WARN_ON(clu < EXFAT_FIRST_CLUSTER);
	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);

	clear_bit_le(b, sbi->vol_amap[i]->b_data);
	exfat_update_bh(sbi->vol_amap[i], IS_DIRSYNC(inode));

	if (opts->discard) {
		int ret_discard;

		ret_discard = sb_issue_discard(sb,
			exfat_cluster_to_sector(sbi, clu +
						EXFAT_RESERVED_CLUSTERS),
			(1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);

		if (ret_discard == -EOPNOTSUPP) {
			exfat_err(sb, "discard not supported by device, disabling");
			opts->discard = 0;
		}
	}
}

/*
 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
 * the cluster heap.
 */
unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
{
	unsigned int i, map_i, map_b, ent_idx;
	unsigned int clu_base, clu_free;
	unsigned char k, clu_mask;
	struct exfat_sb_info *sbi = EXFAT_SB(sb);

	WARN_ON(clu < EXFAT_FIRST_CLUSTER);
	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
	clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx & ~(BITS_PER_BYTE_MASK));
	clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);

	map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
	map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);

	for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
	     i += BITS_PER_BYTE) {
		k = *(sbi->vol_amap[map_i]->b_data + map_b);
		if (clu_mask > 0) {
			k |= clu_mask;
			clu_mask = 0;
		}
		if (k < 0xFF) {
			clu_free = clu_base + free_bit[k];
			if (clu_free < sbi->num_clusters)
				return clu_free;
		}
		clu_base += BITS_PER_BYTE;

		if (++map_b >= sb->s_blocksize ||
		    clu_base >= sbi->num_clusters) {
			if (++map_i >= sbi->map_sectors) {
				clu_base = EXFAT_FIRST_CLUSTER;
				map_i = 0;
			}
			map_b = 0;
		}
	}

	return EXFAT_EOF_CLUSTER;
}

int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
{
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	unsigned int count = 0;
	unsigned int i, map_i = 0, map_b = 0;
	unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
	unsigned int last_mask = total_clus & BITS_PER_BYTE_MASK;
	unsigned char clu_bits;
	const unsigned char last_bit_mask[] = {0, 0b00000001, 0b00000011,
		0b00000111, 0b00001111, 0b00011111, 0b00111111, 0b01111111};

	total_clus &= ~last_mask;
	for (i = 0; i < total_clus; i += BITS_PER_BYTE) {
		clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
		count += used_bit[clu_bits];
		if (++map_b >= (unsigned int)sb->s_blocksize) {
			map_i++;
			map_b = 0;
		}
	}

	if (last_mask) {
		clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
		clu_bits &= last_bit_mask[last_mask];
		count += used_bit[clu_bits];
	}

	*ret_count = count;
	return 0;
}