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/bitmap.h> 9 #include <linux/buffer_head.h> 10 11 #include "exfat_raw.h" 12 #include "exfat_fs.h" 13 14 #if BITS_PER_LONG == 32 15 #define __le_long __le32 16 #define lel_to_cpu(A) le32_to_cpu(A) 17 #define cpu_to_lel(A) cpu_to_le32(A) 18 #elif BITS_PER_LONG == 64 19 #define __le_long __le64 20 #define lel_to_cpu(A) le64_to_cpu(A) 21 #define cpu_to_lel(A) cpu_to_le64(A) 22 #else 23 #error "BITS_PER_LONG not 32 or 64" 24 #endif 25 26 /* 27 * Allocation Bitmap Management Functions 28 */ 29 static int exfat_allocate_bitmap(struct super_block *sb, 30 struct exfat_dentry *ep) 31 { 32 struct exfat_sb_info *sbi = EXFAT_SB(sb); 33 long long map_size; 34 unsigned int i, need_map_size; 35 sector_t sector; 36 37 sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu); 38 map_size = le64_to_cpu(ep->dentry.bitmap.size); 39 need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE) 40 + 1; 41 if (need_map_size != map_size) { 42 exfat_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)", 43 need_map_size, map_size); 44 /* 45 * Only allowed when bogus allocation 46 * bitmap size is large 47 */ 48 if (need_map_size > map_size) 49 return -EIO; 50 } 51 sbi->map_sectors = ((need_map_size - 1) >> 52 (sb->s_blocksize_bits)) + 1; 53 sbi->vol_amap = kvmalloc_array(sbi->map_sectors, 54 sizeof(struct buffer_head *), GFP_KERNEL); 55 if (!sbi->vol_amap) 56 return -ENOMEM; 57 58 sector = exfat_cluster_to_sector(sbi, sbi->map_clu); 59 for (i = 0; i < sbi->map_sectors; i++) { 60 sbi->vol_amap[i] = sb_bread(sb, sector + i); 61 if (!sbi->vol_amap[i]) { 62 /* release all buffers and free vol_amap */ 63 int j = 0; 64 65 while (j < i) 66 brelse(sbi->vol_amap[j++]); 67 68 kvfree(sbi->vol_amap); 69 sbi->vol_amap = NULL; 70 return -EIO; 71 } 72 } 73 74 return 0; 75 } 76 77 int exfat_load_bitmap(struct super_block *sb) 78 { 79 unsigned int i, type; 80 struct exfat_chain clu; 81 struct exfat_sb_info *sbi = EXFAT_SB(sb); 82 83 exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN); 84 while (clu.dir != EXFAT_EOF_CLUSTER) { 85 for (i = 0; i < sbi->dentries_per_clu; i++) { 86 struct exfat_dentry *ep; 87 struct buffer_head *bh; 88 89 ep = exfat_get_dentry(sb, &clu, i, &bh); 90 if (!ep) 91 return -EIO; 92 93 type = exfat_get_entry_type(ep); 94 if (type == TYPE_BITMAP && 95 ep->dentry.bitmap.flags == 0x0) { 96 int err; 97 98 err = exfat_allocate_bitmap(sb, ep); 99 brelse(bh); 100 return err; 101 } 102 brelse(bh); 103 104 if (type == TYPE_UNUSED) 105 return -EINVAL; 106 } 107 108 if (exfat_get_next_cluster(sb, &clu.dir)) 109 return -EIO; 110 } 111 112 return -EINVAL; 113 } 114 115 void exfat_free_bitmap(struct exfat_sb_info *sbi) 116 { 117 int i; 118 119 for (i = 0; i < sbi->map_sectors; i++) 120 __brelse(sbi->vol_amap[i]); 121 122 kvfree(sbi->vol_amap); 123 } 124 125 int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync) 126 { 127 int i, b; 128 unsigned int ent_idx; 129 struct super_block *sb = inode->i_sb; 130 struct exfat_sb_info *sbi = EXFAT_SB(sb); 131 132 if (!is_valid_cluster(sbi, clu)) 133 return -EINVAL; 134 135 ent_idx = CLUSTER_TO_BITMAP_ENT(clu); 136 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 137 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx); 138 139 set_bit_le(b, sbi->vol_amap[i]->b_data); 140 exfat_update_bh(sbi->vol_amap[i], sync); 141 return 0; 142 } 143 144 int exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync) 145 { 146 int i, b; 147 unsigned int ent_idx; 148 struct super_block *sb = inode->i_sb; 149 struct exfat_sb_info *sbi = EXFAT_SB(sb); 150 151 if (!is_valid_cluster(sbi, clu)) 152 return -EIO; 153 154 ent_idx = CLUSTER_TO_BITMAP_ENT(clu); 155 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 156 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx); 157 158 if (!test_bit_le(b, sbi->vol_amap[i]->b_data)) 159 return -EIO; 160 161 clear_bit_le(b, sbi->vol_amap[i]->b_data); 162 163 exfat_update_bh(sbi->vol_amap[i], sync); 164 165 return 0; 166 } 167 168 /* 169 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of 170 * the cluster heap. 171 */ 172 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu) 173 { 174 unsigned int i, map_i, map_b, ent_idx; 175 unsigned int clu_base, clu_free; 176 unsigned long clu_bits, clu_mask; 177 struct exfat_sb_info *sbi = EXFAT_SB(sb); 178 __le_long bitval; 179 180 WARN_ON(clu < EXFAT_FIRST_CLUSTER); 181 ent_idx = ALIGN_DOWN(CLUSTER_TO_BITMAP_ENT(clu), BITS_PER_LONG); 182 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx); 183 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base); 184 185 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 186 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx); 187 188 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; 189 i += BITS_PER_LONG) { 190 bitval = *(__le_long *)(sbi->vol_amap[map_i]->b_data + map_b); 191 if (clu_mask > 0) { 192 bitval |= cpu_to_lel(clu_mask); 193 clu_mask = 0; 194 } 195 if (lel_to_cpu(bitval) != ULONG_MAX) { 196 clu_bits = lel_to_cpu(bitval); 197 clu_free = clu_base + ffz(clu_bits); 198 if (clu_free < sbi->num_clusters) 199 return clu_free; 200 } 201 clu_base += BITS_PER_LONG; 202 map_b += sizeof(long); 203 204 if (map_b >= sb->s_blocksize || 205 clu_base >= sbi->num_clusters) { 206 if (++map_i >= sbi->map_sectors) { 207 clu_base = EXFAT_FIRST_CLUSTER; 208 map_i = 0; 209 } 210 map_b = 0; 211 } 212 } 213 214 return EXFAT_EOF_CLUSTER; 215 } 216 217 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count) 218 { 219 struct exfat_sb_info *sbi = EXFAT_SB(sb); 220 unsigned int count = 0; 221 unsigned int i, map_i = 0, map_b = 0; 222 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi); 223 unsigned int last_mask = total_clus & (BITS_PER_LONG - 1); 224 unsigned long *bitmap, clu_bits; 225 226 total_clus &= ~last_mask; 227 for (i = 0; i < total_clus; i += BITS_PER_LONG) { 228 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b); 229 count += hweight_long(*bitmap); 230 map_b += sizeof(long); 231 if (map_b >= (unsigned int)sb->s_blocksize) { 232 map_i++; 233 map_b = 0; 234 } 235 } 236 237 if (last_mask) { 238 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b); 239 clu_bits = lel_to_cpu(*(__le_long *)bitmap); 240 count += hweight_long(clu_bits & BITMAP_LAST_WORD_MASK(last_mask)); 241 } 242 243 *ret_count = count; 244 return 0; 245 } 246 247 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range) 248 { 249 unsigned int trim_begin, trim_end, count, next_free_clu; 250 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0; 251 struct super_block *sb = inode->i_sb; 252 struct exfat_sb_info *sbi = EXFAT_SB(sb); 253 int err = 0; 254 255 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits, 256 EXFAT_FIRST_CLUSTER); 257 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1; 258 trim_minlen = range->minlen >> sbi->cluster_size_bits; 259 260 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size) 261 return -EINVAL; 262 263 if (clu_end >= sbi->num_clusters) 264 clu_end = sbi->num_clusters - 1; 265 266 mutex_lock(&sbi->bitmap_lock); 267 268 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start); 269 if (trim_begin == EXFAT_EOF_CLUSTER) 270 goto unlock; 271 272 next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1); 273 if (next_free_clu == EXFAT_EOF_CLUSTER) 274 goto unlock; 275 276 do { 277 if (next_free_clu == trim_end + 1) { 278 /* extend trim range for continuous free cluster */ 279 trim_end++; 280 } else { 281 /* trim current range if it's larger than trim_minlen */ 282 count = trim_end - trim_begin + 1; 283 if (count >= trim_minlen) { 284 err = sb_issue_discard(sb, 285 exfat_cluster_to_sector(sbi, trim_begin), 286 count * sbi->sect_per_clus, GFP_NOFS, 0); 287 if (err) 288 goto unlock; 289 290 trimmed_total += count; 291 } 292 293 /* set next start point of the free hole */ 294 trim_begin = trim_end = next_free_clu; 295 } 296 297 if (next_free_clu >= clu_end) 298 break; 299 300 if (fatal_signal_pending(current)) { 301 err = -ERESTARTSYS; 302 goto unlock; 303 } 304 305 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1); 306 } while (next_free_clu != EXFAT_EOF_CLUSTER && 307 next_free_clu > trim_end); 308 309 /* try to trim remainder */ 310 count = trim_end - trim_begin + 1; 311 if (count >= trim_minlen) { 312 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin), 313 count * sbi->sect_per_clus, GFP_NOFS, 0); 314 if (err) 315 goto unlock; 316 317 trimmed_total += count; 318 } 319 320 unlock: 321 mutex_unlock(&sbi->bitmap_lock); 322 range->len = trimmed_total << sbi->cluster_size_bits; 323 324 return err; 325 } 326