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 #include <linux/backing-dev.h> 11 12 #include "exfat_raw.h" 13 #include "exfat_fs.h" 14 15 #if BITS_PER_LONG == 32 16 #define __le_long __le32 17 #define lel_to_cpu(A) le32_to_cpu(A) 18 #define cpu_to_lel(A) cpu_to_le32(A) 19 #elif BITS_PER_LONG == 64 20 #define __le_long __le64 21 #define lel_to_cpu(A) le64_to_cpu(A) 22 #define cpu_to_lel(A) cpu_to_le64(A) 23 #else 24 #error "BITS_PER_LONG not 32 or 64" 25 #endif 26 27 /* 28 * Allocation Bitmap Management Functions 29 */ 30 static bool exfat_test_bitmap_range(struct super_block *sb, unsigned int clu, 31 unsigned int count) 32 { 33 struct exfat_sb_info *sbi = EXFAT_SB(sb); 34 unsigned int start = clu; 35 unsigned int end = clu + count; 36 unsigned int ent_idx, i, b; 37 unsigned int bit_offset, bits_to_check; 38 __le_long *bitmap_le; 39 unsigned long mask, word; 40 41 if (!is_valid_cluster(sbi, start) || !is_valid_cluster(sbi, end - 1)) 42 return false; 43 44 while (start < end) { 45 ent_idx = CLUSTER_TO_BITMAP_ENT(start); 46 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 47 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx); 48 49 bitmap_le = (__le_long *)sbi->vol_amap[i]->b_data; 50 51 /* Calculate how many bits we can check in the current word */ 52 bit_offset = b % BITS_PER_LONG; 53 bits_to_check = min(end - start, 54 (unsigned int)(BITS_PER_LONG - bit_offset)); 55 56 /* Create a bitmask for the range of bits to check */ 57 if (bits_to_check >= BITS_PER_LONG) 58 mask = ~0UL; 59 else 60 mask = ((1UL << bits_to_check) - 1) << bit_offset; 61 word = lel_to_cpu(bitmap_le[b / BITS_PER_LONG]); 62 63 /* Check if all bits in the mask are set */ 64 if ((word & mask) != mask) 65 return false; 66 67 start += bits_to_check; 68 } 69 70 return true; 71 } 72 73 static int exfat_allocate_bitmap(struct super_block *sb, 74 struct exfat_dentry *ep) 75 { 76 struct exfat_sb_info *sbi = EXFAT_SB(sb); 77 struct blk_plug plug; 78 long long map_size; 79 unsigned int i, j, need_map_size; 80 sector_t sector; 81 unsigned int max_ra_count; 82 83 sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu); 84 map_size = le64_to_cpu(ep->dentry.bitmap.size); 85 need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE) 86 + 1; 87 if (need_map_size != map_size) { 88 exfat_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)", 89 need_map_size, map_size); 90 /* 91 * Only allowed when bogus allocation 92 * bitmap size is large 93 */ 94 if (need_map_size > map_size) 95 return -EIO; 96 } 97 sbi->map_sectors = ((need_map_size - 1) >> 98 (sb->s_blocksize_bits)) + 1; 99 sbi->vol_amap = kvmalloc_array(sbi->map_sectors, 100 sizeof(struct buffer_head *), GFP_KERNEL); 101 if (!sbi->vol_amap) 102 return -ENOMEM; 103 104 sector = exfat_cluster_to_sector(sbi, sbi->map_clu); 105 max_ra_count = min(sb->s_bdi->ra_pages, sb->s_bdi->io_pages) << 106 (PAGE_SHIFT - sb->s_blocksize_bits); 107 for (i = 0; i < sbi->map_sectors; i++) { 108 /* Trigger the next readahead in advance. */ 109 if (0 == (i % max_ra_count)) { 110 blk_start_plug(&plug); 111 for (j = i; j < min(max_ra_count, sbi->map_sectors - i) + i; j++) 112 sb_breadahead(sb, sector + j); 113 blk_finish_plug(&plug); 114 } 115 116 sbi->vol_amap[i] = sb_bread(sb, sector + i); 117 if (!sbi->vol_amap[i]) 118 goto err_out; 119 } 120 121 if (exfat_test_bitmap_range(sb, sbi->map_clu, 122 EXFAT_B_TO_CLU_ROUND_UP(map_size, sbi)) == false) 123 goto err_out; 124 125 return 0; 126 127 err_out: 128 j = 0; 129 /* release all buffers and free vol_amap */ 130 while (j < i) 131 brelse(sbi->vol_amap[j++]); 132 133 kvfree(sbi->vol_amap); 134 sbi->vol_amap = NULL; 135 return -EIO; 136 } 137 138 int exfat_load_bitmap(struct super_block *sb) 139 { 140 unsigned int i, type; 141 struct exfat_chain clu; 142 struct exfat_sb_info *sbi = EXFAT_SB(sb); 143 144 exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN); 145 while (clu.dir != EXFAT_EOF_CLUSTER) { 146 for (i = 0; i < sbi->dentries_per_clu; i++) { 147 struct exfat_dentry *ep; 148 struct buffer_head *bh; 149 150 ep = exfat_get_dentry(sb, &clu, i, &bh); 151 if (!ep) 152 return -EIO; 153 154 type = exfat_get_entry_type(ep); 155 if (type == TYPE_BITMAP && 156 ep->dentry.bitmap.flags == 0x0) { 157 int err; 158 159 err = exfat_allocate_bitmap(sb, ep); 160 brelse(bh); 161 return err; 162 } 163 brelse(bh); 164 165 if (type == TYPE_UNUSED) 166 return -EINVAL; 167 } 168 169 if (exfat_get_next_cluster(sb, &clu.dir)) 170 return -EIO; 171 } 172 173 return -EINVAL; 174 } 175 176 void exfat_free_bitmap(struct exfat_sb_info *sbi) 177 { 178 int i; 179 180 for (i = 0; i < sbi->map_sectors; i++) 181 __brelse(sbi->vol_amap[i]); 182 183 kvfree(sbi->vol_amap); 184 } 185 186 int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync) 187 { 188 int i, b; 189 unsigned int ent_idx; 190 struct super_block *sb = inode->i_sb; 191 struct exfat_sb_info *sbi = EXFAT_SB(sb); 192 193 if (!is_valid_cluster(sbi, clu)) 194 return -EINVAL; 195 196 ent_idx = CLUSTER_TO_BITMAP_ENT(clu); 197 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 198 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx); 199 200 set_bit_le(b, sbi->vol_amap[i]->b_data); 201 exfat_update_bh(sbi->vol_amap[i], sync); 202 return 0; 203 } 204 205 int exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync) 206 { 207 int i, b; 208 unsigned int ent_idx; 209 struct super_block *sb = inode->i_sb; 210 struct exfat_sb_info *sbi = EXFAT_SB(sb); 211 212 if (!is_valid_cluster(sbi, clu)) 213 return -EIO; 214 215 ent_idx = CLUSTER_TO_BITMAP_ENT(clu); 216 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 217 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx); 218 219 if (!test_bit_le(b, sbi->vol_amap[i]->b_data)) 220 return -EIO; 221 222 clear_bit_le(b, sbi->vol_amap[i]->b_data); 223 224 exfat_update_bh(sbi->vol_amap[i], sync); 225 226 return 0; 227 } 228 229 /* 230 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of 231 * the cluster heap. 232 */ 233 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu) 234 { 235 unsigned int i, map_i, map_b, ent_idx; 236 unsigned int clu_base, clu_free; 237 unsigned long clu_bits, clu_mask; 238 struct exfat_sb_info *sbi = EXFAT_SB(sb); 239 __le_long bitval; 240 241 WARN_ON(clu < EXFAT_FIRST_CLUSTER); 242 ent_idx = ALIGN_DOWN(CLUSTER_TO_BITMAP_ENT(clu), BITS_PER_LONG); 243 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx); 244 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base); 245 246 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 247 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx); 248 249 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; 250 i += BITS_PER_LONG) { 251 bitval = *(__le_long *)(sbi->vol_amap[map_i]->b_data + map_b); 252 if (clu_mask > 0) { 253 bitval |= cpu_to_lel(clu_mask); 254 clu_mask = 0; 255 } 256 if (lel_to_cpu(bitval) != ULONG_MAX) { 257 clu_bits = lel_to_cpu(bitval); 258 clu_free = clu_base + ffz(clu_bits); 259 if (clu_free < sbi->num_clusters) 260 return clu_free; 261 } 262 clu_base += BITS_PER_LONG; 263 map_b += sizeof(long); 264 265 if (map_b >= sb->s_blocksize || 266 clu_base >= sbi->num_clusters) { 267 if (++map_i >= sbi->map_sectors) { 268 clu_base = EXFAT_FIRST_CLUSTER; 269 map_i = 0; 270 } 271 map_b = 0; 272 } 273 } 274 275 return EXFAT_EOF_CLUSTER; 276 } 277 278 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count) 279 { 280 struct exfat_sb_info *sbi = EXFAT_SB(sb); 281 unsigned int count = 0; 282 unsigned int i, map_i = 0, map_b = 0; 283 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi); 284 unsigned int last_mask = total_clus & (BITS_PER_LONG - 1); 285 unsigned long *bitmap, clu_bits; 286 287 total_clus &= ~last_mask; 288 for (i = 0; i < total_clus; i += BITS_PER_LONG) { 289 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b); 290 count += hweight_long(*bitmap); 291 map_b += sizeof(long); 292 if (map_b >= (unsigned int)sb->s_blocksize) { 293 map_i++; 294 map_b = 0; 295 } 296 } 297 298 if (last_mask) { 299 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b); 300 clu_bits = lel_to_cpu(*(__le_long *)bitmap); 301 count += hweight_long(clu_bits & BITMAP_LAST_WORD_MASK(last_mask)); 302 } 303 304 *ret_count = count; 305 return 0; 306 } 307 308 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range) 309 { 310 unsigned int trim_begin, trim_end, count, next_free_clu; 311 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0; 312 struct super_block *sb = inode->i_sb; 313 struct exfat_sb_info *sbi = EXFAT_SB(sb); 314 int err = 0; 315 316 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits, 317 EXFAT_FIRST_CLUSTER); 318 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1; 319 trim_minlen = range->minlen >> sbi->cluster_size_bits; 320 321 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size) 322 return -EINVAL; 323 324 if (clu_end >= sbi->num_clusters) 325 clu_end = sbi->num_clusters - 1; 326 327 mutex_lock(&sbi->bitmap_lock); 328 329 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start); 330 if (trim_begin == EXFAT_EOF_CLUSTER) 331 goto unlock; 332 333 next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1); 334 if (next_free_clu == EXFAT_EOF_CLUSTER) 335 goto unlock; 336 337 do { 338 if (next_free_clu == trim_end + 1) { 339 /* extend trim range for continuous free cluster */ 340 trim_end++; 341 } else { 342 /* trim current range if it's larger than trim_minlen */ 343 count = trim_end - trim_begin + 1; 344 if (count >= trim_minlen) { 345 err = sb_issue_discard(sb, 346 exfat_cluster_to_sector(sbi, trim_begin), 347 count * sbi->sect_per_clus, GFP_NOFS, 0); 348 if (err) 349 goto unlock; 350 351 trimmed_total += count; 352 } 353 354 /* set next start point of the free hole */ 355 trim_begin = trim_end = next_free_clu; 356 } 357 358 if (next_free_clu >= clu_end) 359 break; 360 361 if (fatal_signal_pending(current)) { 362 err = -ERESTARTSYS; 363 goto unlock; 364 } 365 366 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1); 367 } while (next_free_clu != EXFAT_EOF_CLUSTER && 368 next_free_clu > trim_end); 369 370 /* try to trim remainder */ 371 count = trim_end - trim_begin + 1; 372 if (count >= trim_minlen) { 373 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin), 374 count * sbi->sect_per_clus, GFP_NOFS, 0); 375 if (err) 376 goto unlock; 377 378 trimmed_total += count; 379 } 380 381 unlock: 382 mutex_unlock(&sbi->bitmap_lock); 383 range->len = trimmed_total << sbi->cluster_size_bits; 384 385 return err; 386 } 387