fs/exfat/balloc.c

   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_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)",
  62                           need_map_size, map_size);
  63                 /*
  64                  * Only allowed when bogus allocation
  65                  * bitmap size is large
  66                  */
  67                 if (need_map_size > map_size)
  68                         return -EIO;
  69         }
  70         sbi->map_sectors = ((need_map_size - 1) >>
  71                         (sb->s_blocksize_bits)) + 1;
  72         sbi->vol_amap = kmalloc_array(sbi->map_sectors,
  73                                 sizeof(struct buffer_head *), GFP_KERNEL);
  74         if (!sbi->vol_amap)
  75                 return -ENOMEM;
  76
  77         sector = exfat_cluster_to_sector(sbi, sbi->map_clu);
  78         for (i = 0; i < sbi->map_sectors; i++) {
  79                 sbi->vol_amap[i] = sb_bread(sb, sector + i);
  80                 if (!sbi->vol_amap[i]) {
  81                         /* release all buffers and free vol_amap */
  82                         int j = 0;
  83
  84                         while (j < i)
  85                                 brelse(sbi->vol_amap[j++]);
  86
  87                         kfree(sbi->vol_amap);
  88                         sbi->vol_amap = NULL;
  89                         return -EIO;
  90                 }
  91         }
  92
  93         return 0;
  94 }
  95
  96 int exfat_load_bitmap(struct super_block *sb)
  97 {
  98         unsigned int i, type;
  99         struct exfat_chain clu;
 100         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 101
 102         exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
 103         while (clu.dir != EXFAT_EOF_CLUSTER) {
 104                 for (i = 0; i < sbi->dentries_per_clu; i++) {
 105                         struct exfat_dentry *ep;
 106                         struct buffer_head *bh;
 107
 108                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
 109                         if (!ep)
 110                                 return -EIO;
 111
 112                         type = exfat_get_entry_type(ep);
 113                         if (type == TYPE_UNUSED)
 114                                 break;
 115                         if (type != TYPE_BITMAP)
 116                                 continue;
 117                         if (ep->dentry.bitmap.flags == 0x0) {
 118                                 int err;
 119
 120                                 err = exfat_allocate_bitmap(sb, ep);
 121                                 brelse(bh);
 122                                 return err;
 123                         }
 124                         brelse(bh);
 125                 }
 126
 127                 if (exfat_get_next_cluster(sb, &clu.dir))
 128                         return -EIO;
 129         }
 130
 131         return -EINVAL;
 132 }
 133
 134 void exfat_free_bitmap(struct exfat_sb_info *sbi)
 135 {
 136         int i;
 137
 138         for (i = 0; i < sbi->map_sectors; i++)
 139                 __brelse(sbi->vol_amap[i]);
 140
 141         kfree(sbi->vol_amap);
 142 }
 143
 144 int exfat_set_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         WARN_ON(clu < EXFAT_FIRST_CLUSTER);
 152         ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
 153         i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
 154         b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
 155
 156         set_bit_le(b, sbi->vol_amap[i]->b_data);
 157         exfat_update_bh(sbi->vol_amap[i], sync);
 158         return 0;
 159 }
 160
 161 void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync)
 162 {
 163         int i, b;
 164         unsigned int ent_idx;
 165         struct super_block *sb = inode->i_sb;
 166         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 167         struct exfat_mount_options *opts = &sbi->options;
 168
 169         WARN_ON(clu < EXFAT_FIRST_CLUSTER);
 170         ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
 171         i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
 172         b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
 173
 174         clear_bit_le(b, sbi->vol_amap[i]->b_data);
 175         exfat_update_bh(sbi->vol_amap[i], sync);
 176
 177         if (opts->discard) {
 178                 int ret_discard;
 179
 180                 ret_discard = sb_issue_discard(sb,
 181                         exfat_cluster_to_sector(sbi, clu),
 182                         (1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);
 183
 184                 if (ret_discard == -EOPNOTSUPP) {
 185                         exfat_err(sb, "discard not supported by device, disabling");
 186                         opts->discard = 0;
 187                 }
 188         }
 189 }
 190
 191 /*
 192  * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
 193  * the cluster heap.
 194  */
 195 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
 196 {
 197         unsigned int i, map_i, map_b, ent_idx;
 198         unsigned int clu_base, clu_free;
 199         unsigned char k, clu_mask;
 200         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 201
 202         WARN_ON(clu < EXFAT_FIRST_CLUSTER);
 203         ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
 204         clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx & ~(BITS_PER_BYTE_MASK));
 205         clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);
 206
 207         map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
 208         map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);
 209
 210         for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
 211              i += BITS_PER_BYTE) {
 212                 k = *(sbi->vol_amap[map_i]->b_data + map_b);
 213                 if (clu_mask > 0) {
 214                         k |= clu_mask;
 215                         clu_mask = 0;
 216                 }
 217                 if (k < 0xFF) {
 218                         clu_free = clu_base + free_bit[k];
 219                         if (clu_free < sbi->num_clusters)
 220                                 return clu_free;
 221                 }
 222                 clu_base += BITS_PER_BYTE;
 223
 224                 if (++map_b >= sb->s_blocksize ||
 225                     clu_base >= sbi->num_clusters) {
 226                         if (++map_i >= sbi->map_sectors) {
 227                                 clu_base = EXFAT_FIRST_CLUSTER;
 228                                 map_i = 0;
 229                         }
 230                         map_b = 0;
 231                 }
 232         }
 233
 234         return EXFAT_EOF_CLUSTER;
 235 }
 236
 237 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
 238 {
 239         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 240         unsigned int count = 0;
 241         unsigned int i, map_i = 0, map_b = 0;
 242         unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
 243         unsigned int last_mask = total_clus & BITS_PER_BYTE_MASK;
 244         unsigned char clu_bits;
 245         const unsigned char last_bit_mask[] = {0, 0b00000001, 0b00000011,
 246                 0b00000111, 0b00001111, 0b00011111, 0b00111111, 0b01111111};
 247
 248         total_clus &= ~last_mask;
 249         for (i = 0; i < total_clus; i += BITS_PER_BYTE) {
 250                 clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
 251                 count += used_bit[clu_bits];
 252                 if (++map_b >= (unsigned int)sb->s_blocksize) {
 253                         map_i++;
 254                         map_b = 0;
 255                 }
 256         }
 257
 258         if (last_mask) {
 259                 clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
 260                 clu_bits &= last_bit_mask[last_mask];
 261                 count += used_bit[clu_bits];
 262         }
 263
 264         *ret_count = count;
 265         return 0;
 266 }
 267
 268 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
 269 {
 270         unsigned int trim_begin, trim_end, count, next_free_clu;
 271         u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
 272         struct super_block *sb = inode->i_sb;
 273         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 274         int err = 0;
 275
 276         clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
 277                                 EXFAT_FIRST_CLUSTER);
 278         clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
 279         trim_minlen = range->minlen >> sbi->cluster_size_bits;
 280
 281         if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
 282                 return -EINVAL;
 283
 284         if (clu_end >= sbi->num_clusters)
 285                 clu_end = sbi->num_clusters - 1;
 286
 287         mutex_lock(&sbi->bitmap_lock);
 288
 289         trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start);
 290         if (trim_begin == EXFAT_EOF_CLUSTER)
 291                 goto unlock;
 292
 293         next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1);
 294         if (next_free_clu == EXFAT_EOF_CLUSTER)
 295                 goto unlock;
 296
 297         do {
 298                 if (next_free_clu == trim_end + 1) {
 299                         /* extend trim range for continuous free cluster */
 300                         trim_end++;
 301                 } else {
 302                         /* trim current range if it's larger than trim_minlen */
 303                         count = trim_end - trim_begin + 1;
 304                         if (count >= trim_minlen) {
 305                                 err = sb_issue_discard(sb,
 306                                         exfat_cluster_to_sector(sbi, trim_begin),
 307                                         count * sbi->sect_per_clus, GFP_NOFS, 0);
 308                                 if (err)
 309                                         goto unlock;
 310
 311                                 trimmed_total += count;
 312                         }
 313
 314                         /* set next start point of the free hole */
 315                         trim_begin = trim_end = next_free_clu;
 316                 }
 317
 318                 if (next_free_clu >= clu_end)
 319                         break;
 320
 321                 if (fatal_signal_pending(current)) {
 322                         err = -ERESTARTSYS;
 323                         goto unlock;
 324                 }
 325
 326                 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1);
 327         } while (next_free_clu != EXFAT_EOF_CLUSTER &&
 328                         next_free_clu > trim_end);
 329
 330         /* try to trim remainder */
 331         count = trim_end - trim_begin + 1;
 332         if (count >= trim_minlen) {
 333                 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin),
 334                         count * sbi->sect_per_clus, GFP_NOFS, 0);
 335                 if (err)
 336                         goto unlock;
 337
 338                 trimmed_total += count;
 339         }
 340
 341 unlock:
 342         mutex_unlock(&sbi->bitmap_lock);
 343         range->len = trimmed_total << sbi->cluster_size_bits;
 344
 345         return err;
 346 }