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_UNUSED) 95 break; 96 if (type != TYPE_BITMAP) 97 continue; 98 if (ep->dentry.bitmap.flags == 0x0) { 99 int err; 100 101 err = exfat_allocate_bitmap(sb, ep); 102 brelse(bh); 103 return err; 104 } 105 brelse(bh); 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 void 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 struct exfat_mount_options *opts = &sbi->options; 151 152 if (!is_valid_cluster(sbi, clu)) 153 return; 154 155 ent_idx = CLUSTER_TO_BITMAP_ENT(clu); 156 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 157 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx); 158 159 clear_bit_le(b, sbi->vol_amap[i]->b_data); 160 exfat_update_bh(sbi->vol_amap[i], sync); 161 162 if (opts->discard) { 163 int ret_discard; 164 165 ret_discard = sb_issue_discard(sb, 166 exfat_cluster_to_sector(sbi, clu), 167 (1 << sbi->sect_per_clus_bits), GFP_NOFS, 0); 168 169 if (ret_discard == -EOPNOTSUPP) { 170 exfat_err(sb, "discard not supported by device, disabling"); 171 opts->discard = 0; 172 } 173 } 174 } 175 176 /* 177 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of 178 * the cluster heap. 179 */ 180 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu) 181 { 182 unsigned int i, map_i, map_b, ent_idx; 183 unsigned int clu_base, clu_free; 184 unsigned long clu_bits, clu_mask; 185 struct exfat_sb_info *sbi = EXFAT_SB(sb); 186 __le_long bitval; 187 188 WARN_ON(clu < EXFAT_FIRST_CLUSTER); 189 ent_idx = ALIGN_DOWN(CLUSTER_TO_BITMAP_ENT(clu), BITS_PER_LONG); 190 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx); 191 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base); 192 193 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); 194 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx); 195 196 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; 197 i += BITS_PER_LONG) { 198 bitval = *(__le_long *)(sbi->vol_amap[map_i]->b_data + map_b); 199 if (clu_mask > 0) { 200 bitval |= cpu_to_lel(clu_mask); 201 clu_mask = 0; 202 } 203 if (lel_to_cpu(bitval) != ULONG_MAX) { 204 clu_bits = lel_to_cpu(bitval); 205 clu_free = clu_base + ffz(clu_bits); 206 if (clu_free < sbi->num_clusters) 207 return clu_free; 208 } 209 clu_base += BITS_PER_LONG; 210 map_b += sizeof(long); 211 212 if (map_b >= sb->s_blocksize || 213 clu_base >= sbi->num_clusters) { 214 if (++map_i >= sbi->map_sectors) { 215 clu_base = EXFAT_FIRST_CLUSTER; 216 map_i = 0; 217 } 218 map_b = 0; 219 } 220 } 221 222 return EXFAT_EOF_CLUSTER; 223 } 224 225 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count) 226 { 227 struct exfat_sb_info *sbi = EXFAT_SB(sb); 228 unsigned int count = 0; 229 unsigned int i, map_i = 0, map_b = 0; 230 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi); 231 unsigned int last_mask = total_clus & (BITS_PER_LONG - 1); 232 unsigned long *bitmap, clu_bits; 233 234 total_clus &= ~last_mask; 235 for (i = 0; i < total_clus; i += BITS_PER_LONG) { 236 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b); 237 count += hweight_long(*bitmap); 238 map_b += sizeof(long); 239 if (map_b >= (unsigned int)sb->s_blocksize) { 240 map_i++; 241 map_b = 0; 242 } 243 } 244 245 if (last_mask) { 246 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b); 247 clu_bits = lel_to_cpu(*(__le_long *)bitmap); 248 count += hweight_long(clu_bits & BITMAP_LAST_WORD_MASK(last_mask)); 249 } 250 251 *ret_count = count; 252 return 0; 253 } 254 255 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range) 256 { 257 unsigned int trim_begin, trim_end, count, next_free_clu; 258 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0; 259 struct super_block *sb = inode->i_sb; 260 struct exfat_sb_info *sbi = EXFAT_SB(sb); 261 int err = 0; 262 263 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits, 264 EXFAT_FIRST_CLUSTER); 265 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1; 266 trim_minlen = range->minlen >> sbi->cluster_size_bits; 267 268 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size) 269 return -EINVAL; 270 271 if (clu_end >= sbi->num_clusters) 272 clu_end = sbi->num_clusters - 1; 273 274 mutex_lock(&sbi->bitmap_lock); 275 276 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start); 277 if (trim_begin == EXFAT_EOF_CLUSTER) 278 goto unlock; 279 280 next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1); 281 if (next_free_clu == EXFAT_EOF_CLUSTER) 282 goto unlock; 283 284 do { 285 if (next_free_clu == trim_end + 1) { 286 /* extend trim range for continuous free cluster */ 287 trim_end++; 288 } else { 289 /* trim current range if it's larger than trim_minlen */ 290 count = trim_end - trim_begin + 1; 291 if (count >= trim_minlen) { 292 err = sb_issue_discard(sb, 293 exfat_cluster_to_sector(sbi, trim_begin), 294 count * sbi->sect_per_clus, GFP_NOFS, 0); 295 if (err) 296 goto unlock; 297 298 trimmed_total += count; 299 } 300 301 /* set next start point of the free hole */ 302 trim_begin = trim_end = next_free_clu; 303 } 304 305 if (next_free_clu >= clu_end) 306 break; 307 308 if (fatal_signal_pending(current)) { 309 err = -ERESTARTSYS; 310 goto unlock; 311 } 312 313 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1); 314 } while (next_free_clu != EXFAT_EOF_CLUSTER && 315 next_free_clu > trim_end); 316 317 /* try to trim remainder */ 318 count = trim_end - trim_begin + 1; 319 if (count >= trim_minlen) { 320 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin), 321 count * sbi->sect_per_clus, GFP_NOFS, 0); 322 if (err) 323 goto unlock; 324 325 trimmed_total += count; 326 } 327 328 unlock: 329 mutex_unlock(&sbi->bitmap_lock); 330 range->len = trimmed_total << sbi->cluster_size_bits; 331 332 return err; 333 } 334