1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. 4 */ 5 6 #include <linux/blkdev.h> 7 #include <linux/slab.h> 8 #include <linux/buffer_head.h> 9 10 #include "exfat_raw.h" 11 #include "exfat_fs.h" 12 13 static const unsigned char free_bit[] = { 14 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/* 0 ~ 19*/ 15 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3,/* 20 ~ 39*/ 16 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/* 40 ~ 59*/ 17 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/* 60 ~ 79*/ 18 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2,/* 80 ~ 99*/ 19 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3,/*100 ~ 119*/ 20 0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*120 ~ 139*/ 21 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,/*140 ~ 159*/ 22 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/*160 ~ 179*/ 23 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3,/*180 ~ 199*/ 24 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*200 ~ 219*/ 25 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/*220 ~ 239*/ 26 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 /*240 ~ 254*/ 27 }; 28 29 static const unsigned char used_bit[] = { 30 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3,/* 0 ~ 19*/ 31 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4,/* 20 ~ 39*/ 32 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5,/* 40 ~ 59*/ 33 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,/* 60 ~ 79*/ 34 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4,/* 80 ~ 99*/ 35 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,/*100 ~ 119*/ 36 4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4,/*120 ~ 139*/ 37 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,/*140 ~ 159*/ 38 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5,/*160 ~ 179*/ 39 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4, 5,/*180 ~ 199*/ 40 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6,/*200 ~ 219*/ 41 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,/*220 ~ 239*/ 42 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8 /*240 ~ 255*/ 43 }; 44 45 /* 46 * Allocation Bitmap Management Functions 47 */ 48 static int exfat_allocate_bitmap(struct super_block *sb, 49 struct exfat_dentry *ep) 50 { 51 struct exfat_sb_info *sbi = EXFAT_SB(sb); 52 long long map_size; 53 unsigned int i, need_map_size; 54 sector_t sector; 55 56 sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu); 57 map_size = le64_to_cpu(ep->dentry.bitmap.size); 58 need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE) 59 + 1; 60 if (need_map_size != map_size) { 61 exfat_msg(sb, KERN_ERR, 62 "bogus allocation bitmap size(need : %u, cur : %lld)", 63 need_map_size, map_size); 64 /* 65 * Only allowed when bogus allocation 66 * bitmap size is large 67 */ 68 if (need_map_size > map_size) 69 return -EIO; 70 } 71 sbi->map_sectors = ((need_map_size - 1) >> 72 (sb->s_blocksize_bits)) + 1; 73 sbi->vol_amap = kmalloc_array(sbi->map_sectors, 74 sizeof(struct buffer_head *), GFP_KERNEL); 75 if (!sbi->vol_amap) 76 return -ENOMEM; 77 78 sector = exfat_cluster_to_sector(sbi, sbi->map_clu); 79 for (i = 0; i < sbi->map_sectors; i++) { 80 sbi->vol_amap[i] = sb_bread(sb, sector + i); 81 if (!sbi->vol_amap[i]) { 82 /* release all buffers and free vol_amap */ 83 int j = 0; 84 85 while (j < i) 86 brelse(sbi->vol_amap[j++]); 87 88 kfree(sbi->vol_amap); 89 sbi->vol_amap = NULL; 90 return -EIO; 91 } 92 } 93 94 return 0; 95 } 96 97 int exfat_load_bitmap(struct super_block *sb) 98 { 99 unsigned int i, type; 100 struct exfat_chain clu; 101 struct exfat_sb_info *sbi = EXFAT_SB(sb); 102 103 exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN); 104 while (clu.dir != EXFAT_EOF_CLUSTER) { 105 for (i = 0; i < sbi->dentries_per_clu; i++) { 106 struct exfat_dentry *ep; 107 struct buffer_head *bh; 108 109 ep = exfat_get_dentry(sb, &clu, i, &bh, NULL); 110 if (!ep) 111 return -EIO; 112 113 type = exfat_get_entry_type(ep); 114 if (type == TYPE_UNUSED) 115 break; 116 if (type != TYPE_BITMAP) 117 continue; 118 if (ep->dentry.bitmap.flags == 0x0) { 119 int err; 120 121 err = exfat_allocate_bitmap(sb, ep); 122 brelse(bh); 123 return err; 124 } 125 brelse(bh); 126 } 127 128 if (exfat_get_next_cluster(sb, &clu.dir)) 129 return -EIO; 130 } 131 132 return -EINVAL; 133 } 134 135 void exfat_free_bitmap(struct exfat_sb_info *sbi) 136 { 137 int i; 138 139 for (i = 0; i < sbi->map_sectors; i++) 140 __brelse(sbi->vol_amap[i]); 141 142 kfree(sbi->vol_amap); 143 } 144 145 /* 146 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of 147 * the cluster heap. 148 */ 149 int exfat_set_bitmap(struct inode *inode, unsigned int clu) 150 { 151 int i, b; 152 unsigned int ent_idx; 153 struct super_block *sb = inode->i_sb; 154 struct exfat_sb_info *sbi = EXFAT_SB(sb); 155 156 WARN_ON(clu < EXFAT_FIRST_CLUSTER); 157 ent_idx = CLUSTER_TO_BITMAP_ENT(clu); 158 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 159 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx); 160 161 set_bit_le(b, sbi->vol_amap[i]->b_data); 162 exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode)); 163 return 0; 164 } 165 166 /* 167 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of 168 * the cluster heap. 169 */ 170 void exfat_clear_bitmap(struct inode *inode, unsigned int clu) 171 { 172 int i, b; 173 unsigned int ent_idx; 174 struct super_block *sb = inode->i_sb; 175 struct exfat_sb_info *sbi = EXFAT_SB(sb); 176 struct exfat_mount_options *opts = &sbi->options; 177 178 WARN_ON(clu < EXFAT_FIRST_CLUSTER); 179 ent_idx = CLUSTER_TO_BITMAP_ENT(clu); 180 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 181 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx); 182 183 clear_bit_le(b, sbi->vol_amap[i]->b_data); 184 exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode)); 185 186 if (opts->discard) { 187 int ret_discard; 188 189 ret_discard = sb_issue_discard(sb, 190 exfat_cluster_to_sector(sbi, clu + 191 EXFAT_RESERVED_CLUSTERS), 192 (1 << sbi->sect_per_clus_bits), GFP_NOFS, 0); 193 194 if (ret_discard == -EOPNOTSUPP) { 195 exfat_msg(sb, KERN_ERR, 196 "discard not supported by device, disabling"); 197 opts->discard = 0; 198 } 199 } 200 } 201 202 /* 203 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of 204 * the cluster heap. 205 */ 206 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu) 207 { 208 unsigned int i, map_i, map_b, ent_idx; 209 unsigned int clu_base, clu_free; 210 unsigned char k, clu_mask; 211 struct exfat_sb_info *sbi = EXFAT_SB(sb); 212 213 WARN_ON(clu < EXFAT_FIRST_CLUSTER); 214 ent_idx = CLUSTER_TO_BITMAP_ENT(clu); 215 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx & ~(BITS_PER_BYTE_MASK)); 216 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base); 217 218 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 219 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx); 220 221 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; 222 i += BITS_PER_BYTE) { 223 k = *(sbi->vol_amap[map_i]->b_data + map_b); 224 if (clu_mask > 0) { 225 k |= clu_mask; 226 clu_mask = 0; 227 } 228 if (k < 0xFF) { 229 clu_free = clu_base + free_bit[k]; 230 if (clu_free < sbi->num_clusters) 231 return clu_free; 232 } 233 clu_base += BITS_PER_BYTE; 234 235 if (++map_b >= sb->s_blocksize || 236 clu_base >= sbi->num_clusters) { 237 if (++map_i >= sbi->map_sectors) { 238 clu_base = EXFAT_FIRST_CLUSTER; 239 map_i = 0; 240 } 241 map_b = 0; 242 } 243 } 244 245 return EXFAT_EOF_CLUSTER; 246 } 247 248 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count) 249 { 250 struct exfat_sb_info *sbi = EXFAT_SB(sb); 251 unsigned int count = 0; 252 unsigned int i, map_i = 0, map_b = 0; 253 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi); 254 unsigned int last_mask = total_clus & BITS_PER_BYTE_MASK; 255 unsigned char clu_bits; 256 const unsigned char last_bit_mask[] = {0, 0b00000001, 0b00000011, 257 0b00000111, 0b00001111, 0b00011111, 0b00111111, 0b01111111}; 258 259 total_clus &= ~last_mask; 260 for (i = 0; i < total_clus; i += BITS_PER_BYTE) { 261 clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b); 262 count += used_bit[clu_bits]; 263 if (++map_b >= (unsigned int)sb->s_blocksize) { 264 map_i++; 265 map_b = 0; 266 } 267 } 268 269 if (last_mask) { 270 clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b); 271 clu_bits &= last_bit_mask[last_mask]; 272 count += used_bit[clu_bits]; 273 } 274 275 *ret_count = count; 276 return 0; 277 } 278