fs/exfat/inode.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/init.h>
   7 #include <linux/buffer_head.h>
   8 #include <linux/mpage.h>
   9 #include <linux/bio.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/time.h>
  12 #include <linux/writeback.h>
  13 #include <linux/uio.h>
  14 #include <linux/random.h>
  15 #include <linux/iversion.h>
  16
  17 #include "exfat_raw.h"
  18 #include "exfat_fs.h"
  19
  20 int __exfat_write_inode(struct inode *inode, int sync)
  21 {
  22         unsigned long long on_disk_size;
  23         struct exfat_dentry *ep, *ep2;
  24         struct exfat_entry_set_cache es;
  25         struct super_block *sb = inode->i_sb;
  26         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  27         struct exfat_inode_info *ei = EXFAT_I(inode);
  28         bool is_dir = (ei->type == TYPE_DIR) ? true : false;
  29         struct timespec64 ts;
  30
  31         if (inode->i_ino == EXFAT_ROOT_INO)
  32                 return 0;
  33
  34         /*
  35          * If the inode is already unlinked, there is no need for updating it.
  36          */
  37         if (ei->dir.dir == DIR_DELETED)
  38                 return 0;
  39
  40         if (is_dir && ei->dir.dir == sbi->root_dir && ei->entry == -1)
  41                 return 0;
  42
  43         exfat_set_volume_dirty(sb);
  44
  45         /* get the directory entry of given file or directory */
  46         if (exfat_get_dentry_set(&es, sb, &(ei->dir), ei->entry, ES_ALL_ENTRIES))
  47                 return -EIO;
  48         ep = exfat_get_dentry_cached(&es, ES_IDX_FILE);
  49         ep2 = exfat_get_dentry_cached(&es, ES_IDX_STREAM);
  50
  51         ep->dentry.file.attr = cpu_to_le16(exfat_make_attr(inode));
  52
  53         /* set FILE_INFO structure using the acquired struct exfat_dentry */
  54         exfat_set_entry_time(sbi, &ei->i_crtime,
  55                         &ep->dentry.file.create_tz,
  56                         &ep->dentry.file.create_time,
  57                         &ep->dentry.file.create_date,
  58                         &ep->dentry.file.create_time_cs);
  59         ts = inode_get_mtime(inode);
  60         exfat_set_entry_time(sbi, &ts,
  61                              &ep->dentry.file.modify_tz,
  62                              &ep->dentry.file.modify_time,
  63                              &ep->dentry.file.modify_date,
  64                              &ep->dentry.file.modify_time_cs);
  65         ts = inode_get_atime(inode);
  66         exfat_set_entry_time(sbi, &ts,
  67                              &ep->dentry.file.access_tz,
  68                              &ep->dentry.file.access_time,
  69                              &ep->dentry.file.access_date,
  70                              NULL);
  71
  72         /* File size should be zero if there is no cluster allocated */
  73         on_disk_size = i_size_read(inode);
  74
  75         if (ei->start_clu == EXFAT_EOF_CLUSTER)
  76                 on_disk_size = 0;
  77
  78         ep2->dentry.stream.size = cpu_to_le64(on_disk_size);
  79         /*
  80          * mmap write does not use exfat_write_end(), valid_size may be
  81          * extended to the sector-aligned length in exfat_get_block().
  82          * So we need to fixup valid_size to the writren length.
  83          */
  84         if (on_disk_size < ei->valid_size)
  85                 ep2->dentry.stream.valid_size = ep2->dentry.stream.size;
  86         else
  87                 ep2->dentry.stream.valid_size = cpu_to_le64(ei->valid_size);
  88
  89         if (on_disk_size) {
  90                 ep2->dentry.stream.flags = ei->flags;
  91                 ep2->dentry.stream.start_clu = cpu_to_le32(ei->start_clu);
  92         } else {
  93                 ep2->dentry.stream.flags = ALLOC_FAT_CHAIN;
  94                 ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER;
  95         }
  96
  97         exfat_update_dir_chksum(&es);
  98         return exfat_put_dentry_set(&es, sync);
  99 }
 100
 101 int exfat_write_inode(struct inode *inode, struct writeback_control *wbc)
 102 {
 103         int ret;
 104
 105         mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
 106         ret = __exfat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 107         mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
 108
 109         return ret;
 110 }
 111
 112 void exfat_sync_inode(struct inode *inode)
 113 {
 114         lockdep_assert_held(&EXFAT_SB(inode->i_sb)->s_lock);
 115         __exfat_write_inode(inode, 1);
 116 }
 117
 118 /*
 119  * Input: inode, (logical) clu_offset, target allocation area
 120  * Output: errcode, cluster number
 121  * *clu = (~0), if it's unable to allocate a new cluster
 122  */
 123 static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
 124                 unsigned int *clu, int create)
 125 {
 126         int ret;
 127         unsigned int last_clu;
 128         struct exfat_chain new_clu;
 129         struct super_block *sb = inode->i_sb;
 130         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 131         struct exfat_inode_info *ei = EXFAT_I(inode);
 132         unsigned int local_clu_offset = clu_offset;
 133         unsigned int num_to_be_allocated = 0, num_clusters = 0;
 134
 135         if (ei->i_size_ondisk > 0)
 136                 num_clusters =
 137                         EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi);
 138
 139         if (clu_offset >= num_clusters)
 140                 num_to_be_allocated = clu_offset - num_clusters + 1;
 141
 142         if (!create && (num_to_be_allocated > 0)) {
 143                 *clu = EXFAT_EOF_CLUSTER;
 144                 return 0;
 145         }
 146
 147         *clu = last_clu = ei->start_clu;
 148
 149         if (ei->flags == ALLOC_NO_FAT_CHAIN) {
 150                 if (clu_offset > 0 && *clu != EXFAT_EOF_CLUSTER) {
 151                         last_clu += clu_offset - 1;
 152
 153                         if (clu_offset == num_clusters)
 154                                 *clu = EXFAT_EOF_CLUSTER;
 155                         else
 156                                 *clu += clu_offset;
 157                 }
 158         } else if (ei->type == TYPE_FILE) {
 159                 unsigned int fclus = 0;
 160                 int err = exfat_get_cluster(inode, clu_offset,
 161                                 &fclus, clu, &last_clu, 1);
 162                 if (err)
 163                         return -EIO;
 164
 165                 clu_offset -= fclus;
 166         } else {
 167                 /* hint information */
 168                 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
 169                     ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
 170                         clu_offset -= ei->hint_bmap.off;
 171                         /* hint_bmap.clu should be valid */
 172                         WARN_ON(ei->hint_bmap.clu < 2);
 173                         *clu = ei->hint_bmap.clu;
 174                 }
 175
 176                 while (clu_offset > 0 && *clu != EXFAT_EOF_CLUSTER) {
 177                         last_clu = *clu;
 178                         if (exfat_get_next_cluster(sb, clu))
 179                                 return -EIO;
 180                         clu_offset--;
 181                 }
 182         }
 183
 184         if (*clu == EXFAT_EOF_CLUSTER) {
 185                 exfat_set_volume_dirty(sb);
 186
 187                 new_clu.dir = (last_clu == EXFAT_EOF_CLUSTER) ?
 188                                 EXFAT_EOF_CLUSTER : last_clu + 1;
 189                 new_clu.size = 0;
 190                 new_clu.flags = ei->flags;
 191
 192                 /* allocate a cluster */
 193                 if (num_to_be_allocated < 1) {
 194                         /* Broken FAT (i_sze > allocated FAT) */
 195                         exfat_fs_error(sb, "broken FAT chain.");
 196                         return -EIO;
 197                 }
 198
 199                 ret = exfat_alloc_cluster(inode, num_to_be_allocated, &new_clu,
 200                                 inode_needs_sync(inode));
 201                 if (ret)
 202                         return ret;
 203
 204                 if (new_clu.dir == EXFAT_EOF_CLUSTER ||
 205                     new_clu.dir == EXFAT_FREE_CLUSTER) {
 206                         exfat_fs_error(sb,
 207                                 "bogus cluster new allocated (last_clu : %u, new_clu : %u)",
 208                                 last_clu, new_clu.dir);
 209                         return -EIO;
 210                 }
 211
 212                 /* append to the FAT chain */
 213                 if (last_clu == EXFAT_EOF_CLUSTER) {
 214                         if (new_clu.flags == ALLOC_FAT_CHAIN)
 215                                 ei->flags = ALLOC_FAT_CHAIN;
 216                         ei->start_clu = new_clu.dir;
 217                 } else {
 218                         if (new_clu.flags != ei->flags) {
 219                                 /* no-fat-chain bit is disabled,
 220                                  * so fat-chain should be synced with
 221                                  * alloc-bitmap
 222                                  */
 223                                 exfat_chain_cont_cluster(sb, ei->start_clu,
 224                                         num_clusters);
 225                                 ei->flags = ALLOC_FAT_CHAIN;
 226                         }
 227                         if (new_clu.flags == ALLOC_FAT_CHAIN)
 228                                 if (exfat_ent_set(sb, last_clu, new_clu.dir))
 229                                         return -EIO;
 230                 }
 231
 232                 num_clusters += num_to_be_allocated;
 233                 *clu = new_clu.dir;
 234
 235                 inode->i_blocks += EXFAT_CLU_TO_B(num_to_be_allocated, sbi) >> 9;
 236
 237                 /*
 238                  * Move *clu pointer along FAT chains (hole care) because the
 239                  * caller of this function expect *clu to be the last cluster.
 240                  * This only works when num_to_be_allocated >= 2,
 241                  * *clu = (the first cluster of the allocated chain) =>
 242                  * (the last cluster of ...)
 243                  */
 244                 if (ei->flags == ALLOC_NO_FAT_CHAIN) {
 245                         *clu += num_to_be_allocated - 1;
 246                 } else {
 247                         while (num_to_be_allocated > 1) {
 248                                 if (exfat_get_next_cluster(sb, clu))
 249                                         return -EIO;
 250                                 num_to_be_allocated--;
 251                         }
 252                 }
 253
 254         }
 255
 256         /* hint information */
 257         ei->hint_bmap.off = local_clu_offset;
 258         ei->hint_bmap.clu = *clu;
 259
 260         return 0;
 261 }
 262
 263 static int exfat_map_new_buffer(struct exfat_inode_info *ei,
 264                 struct buffer_head *bh, loff_t pos)
 265 {
 266         if (buffer_delay(bh) && pos > ei->i_size_aligned)
 267                 return -EIO;
 268         set_buffer_new(bh);
 269
 270         /*
 271          * Adjust i_size_aligned if i_size_ondisk is bigger than it.
 272          */
 273         if (ei->i_size_ondisk > ei->i_size_aligned)
 274                 ei->i_size_aligned = ei->i_size_ondisk;
 275         return 0;
 276 }
 277
 278 static int exfat_get_block(struct inode *inode, sector_t iblock,
 279                 struct buffer_head *bh_result, int create)
 280 {
 281         struct exfat_inode_info *ei = EXFAT_I(inode);
 282         struct super_block *sb = inode->i_sb;
 283         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 284         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
 285         int err = 0;
 286         unsigned long mapped_blocks = 0;
 287         unsigned int cluster, sec_offset;
 288         sector_t last_block;
 289         sector_t phys = 0;
 290         sector_t valid_blks;
 291         loff_t pos;
 292
 293         mutex_lock(&sbi->s_lock);
 294         last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size_read(inode), sb);
 295         if (iblock >= last_block && !create)
 296                 goto done;
 297
 298         /* Is this block already allocated? */
 299         err = exfat_map_cluster(inode, iblock >> sbi->sect_per_clus_bits,
 300                         &cluster, create);
 301         if (err) {
 302                 if (err != -ENOSPC)
 303                         exfat_fs_error_ratelimit(sb,
 304                                 "failed to bmap (inode : %p iblock : %llu, err : %d)",
 305                                 inode, (unsigned long long)iblock, err);
 306                 goto unlock_ret;
 307         }
 308
 309         if (cluster == EXFAT_EOF_CLUSTER)
 310                 goto done;
 311
 312         /* sector offset in cluster */
 313         sec_offset = iblock & (sbi->sect_per_clus - 1);
 314
 315         phys = exfat_cluster_to_sector(sbi, cluster) + sec_offset;
 316         mapped_blocks = sbi->sect_per_clus - sec_offset;
 317         max_blocks = min(mapped_blocks, max_blocks);
 318
 319         pos = EXFAT_BLK_TO_B((iblock + 1), sb);
 320         if ((create && iblock >= last_block) || buffer_delay(bh_result)) {
 321                 if (ei->i_size_ondisk < pos)
 322                         ei->i_size_ondisk = pos;
 323         }
 324
 325         map_bh(bh_result, sb, phys);
 326         if (buffer_delay(bh_result))
 327                 clear_buffer_delay(bh_result);
 328
 329         if (create) {
 330                 valid_blks = EXFAT_B_TO_BLK_ROUND_UP(ei->valid_size, sb);
 331
 332                 if (iblock + max_blocks < valid_blks) {
 333                         /* The range has been written, map it */
 334                         goto done;
 335                 } else if (iblock < valid_blks) {
 336                         /*
 337                          * The range has been partially written,
 338                          * map the written part.
 339                          */
 340                         max_blocks = valid_blks - iblock;
 341                         goto done;
 342                 }
 343
 344                 /* The area has not been written, map and mark as new. */
 345                 err = exfat_map_new_buffer(ei, bh_result, pos);
 346                 if (err) {
 347                         exfat_fs_error(sb,
 348                                         "requested for bmap out of range(pos : (%llu) > i_size_aligned(%llu)\n",
 349                                         pos, ei->i_size_aligned);
 350                         goto unlock_ret;
 351                 }
 352
 353                 ei->valid_size = EXFAT_BLK_TO_B(iblock + max_blocks, sb);
 354                 mark_inode_dirty(inode);
 355         } else {
 356                 valid_blks = EXFAT_B_TO_BLK(ei->valid_size, sb);
 357
 358                 if (iblock + max_blocks < valid_blks) {
 359                         /* The range has been written, map it */
 360                         goto done;
 361                 } else if (iblock < valid_blks) {
 362                         /*
 363                          * The area has been partially written,
 364                          * map the written part.
 365                          */
 366                         max_blocks = valid_blks - iblock;
 367                         goto done;
 368                 } else if (iblock == valid_blks &&
 369                            (ei->valid_size & (sb->s_blocksize - 1))) {
 370                         /*
 371                          * The block has been partially written,
 372                          * zero the unwritten part and map the block.
 373                          */
 374                         loff_t size, off;
 375
 376                         max_blocks = 1;
 377
 378                         /*
 379                          * For direct read, the unwritten part will be zeroed in
 380                          * exfat_direct_IO()
 381                          */
 382                         if (!bh_result->b_folio)
 383                                 goto done;
 384
 385                         pos -= sb->s_blocksize;
 386                         size = ei->valid_size - pos;
 387                         off = pos & (PAGE_SIZE - 1);
 388
 389                         folio_set_bh(bh_result, bh_result->b_folio, off);
 390                         err = bh_read(bh_result, 0);
 391                         if (err < 0)
 392                                 goto unlock_ret;
 393
 394                         folio_zero_segment(bh_result->b_folio, off + size,
 395                                         off + sb->s_blocksize);
 396                 } else {
 397                         /*
 398                          * The range has not been written, clear the mapped flag
 399                          * to only zero the cache and do not read from disk.
 400                          */
 401                         clear_buffer_mapped(bh_result);
 402                 }
 403         }
 404 done:
 405         bh_result->b_size = EXFAT_BLK_TO_B(max_blocks, sb);
 406 unlock_ret:
 407         mutex_unlock(&sbi->s_lock);
 408         return err;
 409 }
 410
 411 static int exfat_read_folio(struct file *file, struct folio *folio)
 412 {
 413         return mpage_read_folio(folio, exfat_get_block);
 414 }
 415
 416 static void exfat_readahead(struct readahead_control *rac)
 417 {
 418         struct address_space *mapping = rac->mapping;
 419         struct inode *inode = mapping->host;
 420         struct exfat_inode_info *ei = EXFAT_I(inode);
 421         loff_t pos = readahead_pos(rac);
 422
 423         /* Range cross valid_size, read it page by page. */
 424         if (ei->valid_size < i_size_read(inode) &&
 425             pos <= ei->valid_size &&
 426             ei->valid_size < pos + readahead_length(rac))
 427                 return;
 428
 429         mpage_readahead(rac, exfat_get_block);
 430 }
 431
 432 static int exfat_writepages(struct address_space *mapping,
 433                 struct writeback_control *wbc)
 434 {
 435         return mpage_writepages(mapping, wbc, exfat_get_block);
 436 }
 437
 438 static void exfat_write_failed(struct address_space *mapping, loff_t to)
 439 {
 440         struct inode *inode = mapping->host;
 441
 442         if (to > i_size_read(inode)) {
 443                 truncate_pagecache(inode, i_size_read(inode));
 444                 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
 445                 exfat_truncate(inode);
 446         }
 447 }
 448
 449 static int exfat_write_begin(struct file *file, struct address_space *mapping,
 450                 loff_t pos, unsigned int len,
 451                 struct page **pagep, void **fsdata)
 452 {
 453         int ret;
 454
 455         *pagep = NULL;
 456         ret = block_write_begin(mapping, pos, len, pagep, exfat_get_block);
 457
 458         if (ret < 0)
 459                 exfat_write_failed(mapping, pos+len);
 460
 461         return ret;
 462 }
 463
 464 static int exfat_write_end(struct file *file, struct address_space *mapping,
 465                 loff_t pos, unsigned int len, unsigned int copied,
 466                 struct page *pagep, void *fsdata)
 467 {
 468         struct inode *inode = mapping->host;
 469         struct exfat_inode_info *ei = EXFAT_I(inode);
 470         int err;
 471
 472         err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
 473
 474         if (ei->i_size_aligned < i_size_read(inode)) {
 475                 exfat_fs_error(inode->i_sb,
 476                         "invalid size(size(%llu) > aligned(%llu)\n",
 477                         i_size_read(inode), ei->i_size_aligned);
 478                 return -EIO;
 479         }
 480
 481         if (err < len)
 482                 exfat_write_failed(mapping, pos+len);
 483
 484         if (!(err < 0) && pos + err > ei->valid_size) {
 485                 ei->valid_size = pos + err;
 486                 mark_inode_dirty(inode);
 487         }
 488
 489         if (!(err < 0) && !(ei->attr & EXFAT_ATTR_ARCHIVE)) {
 490                 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
 491                 ei->attr |= EXFAT_ATTR_ARCHIVE;
 492                 mark_inode_dirty(inode);
 493         }
 494
 495         return err;
 496 }
 497
 498 static ssize_t exfat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 499 {
 500         struct address_space *mapping = iocb->ki_filp->f_mapping;
 501         struct inode *inode = mapping->host;
 502         struct exfat_inode_info *ei = EXFAT_I(inode);
 503         loff_t pos = iocb->ki_pos;
 504         loff_t size = pos + iov_iter_count(iter);
 505         int rw = iov_iter_rw(iter);
 506         ssize_t ret;
 507
 508         if (rw == WRITE) {
 509                 /*
 510                  * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
 511                  * so we need to update the ->i_size_aligned to block boundary.
 512                  *
 513                  * But we must fill the remaining area or hole by nul for
 514                  * updating ->i_size_aligned
 515                  *
 516                  * Return 0, and fallback to normal buffered write.
 517                  */
 518                 if (EXFAT_I(inode)->i_size_aligned < size)
 519                         return 0;
 520         }
 521
 522         /*
 523          * Need to use the DIO_LOCKING for avoiding the race
 524          * condition of exfat_get_block() and ->truncate().
 525          */
 526         ret = blockdev_direct_IO(iocb, inode, iter, exfat_get_block);
 527         if (ret < 0) {
 528                 if (rw == WRITE && ret != -EIOCBQUEUED)
 529                         exfat_write_failed(mapping, size);
 530
 531                 return ret;
 532         } else
 533                 size = pos + ret;
 534
 535         /* zero the unwritten part in the partially written block */
 536         if (rw == READ && pos < ei->valid_size && ei->valid_size < size) {
 537                 iov_iter_revert(iter, size - ei->valid_size);
 538                 iov_iter_zero(size - ei->valid_size, iter);
 539         }
 540
 541         return ret;
 542 }
 543
 544 static sector_t exfat_aop_bmap(struct address_space *mapping, sector_t block)
 545 {
 546         sector_t blocknr;
 547
 548         /* exfat_get_cluster() assumes the requested blocknr isn't truncated. */
 549         down_read(&EXFAT_I(mapping->host)->truncate_lock);
 550         blocknr = generic_block_bmap(mapping, block, exfat_get_block);
 551         up_read(&EXFAT_I(mapping->host)->truncate_lock);
 552         return blocknr;
 553 }
 554
 555 /*
 556  * exfat_block_truncate_page() zeroes out a mapping from file offset `from'
 557  * up to the end of the block which corresponds to `from'.
 558  * This is required during truncate to physically zeroout the tail end
 559  * of that block so it doesn't yield old data if the file is later grown.
 560  * Also, avoid causing failure from fsx for cases of "data past EOF"
 561  */
 562 int exfat_block_truncate_page(struct inode *inode, loff_t from)
 563 {
 564         return block_truncate_page(inode->i_mapping, from, exfat_get_block);
 565 }
 566
 567 static const struct address_space_operations exfat_aops = {
 568         .dirty_folio    = block_dirty_folio,
 569         .invalidate_folio = block_invalidate_folio,
 570         .read_folio     = exfat_read_folio,
 571         .readahead      = exfat_readahead,
 572         .writepages     = exfat_writepages,
 573         .write_begin    = exfat_write_begin,
 574         .write_end      = exfat_write_end,
 575         .direct_IO      = exfat_direct_IO,
 576         .bmap           = exfat_aop_bmap,
 577         .migrate_folio  = buffer_migrate_folio,
 578 };
 579
 580 static inline unsigned long exfat_hash(loff_t i_pos)
 581 {
 582         return hash_32(i_pos, EXFAT_HASH_BITS);
 583 }
 584
 585 void exfat_hash_inode(struct inode *inode, loff_t i_pos)
 586 {
 587         struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
 588         struct hlist_head *head = sbi->inode_hashtable + exfat_hash(i_pos);
 589
 590         spin_lock(&sbi->inode_hash_lock);
 591         EXFAT_I(inode)->i_pos = i_pos;
 592         hlist_add_head(&EXFAT_I(inode)->i_hash_fat, head);
 593         spin_unlock(&sbi->inode_hash_lock);
 594 }
 595
 596 void exfat_unhash_inode(struct inode *inode)
 597 {
 598         struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
 599
 600         spin_lock(&sbi->inode_hash_lock);
 601         hlist_del_init(&EXFAT_I(inode)->i_hash_fat);
 602         EXFAT_I(inode)->i_pos = 0;
 603         spin_unlock(&sbi->inode_hash_lock);
 604 }
 605
 606 struct inode *exfat_iget(struct super_block *sb, loff_t i_pos)
 607 {
 608         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 609         struct exfat_inode_info *info;
 610         struct hlist_head *head = sbi->inode_hashtable + exfat_hash(i_pos);
 611         struct inode *inode = NULL;
 612
 613         spin_lock(&sbi->inode_hash_lock);
 614         hlist_for_each_entry(info, head, i_hash_fat) {
 615                 WARN_ON(info->vfs_inode.i_sb != sb);
 616
 617                 if (i_pos != info->i_pos)
 618                         continue;
 619                 inode = igrab(&info->vfs_inode);
 620                 if (inode)
 621                         break;
 622         }
 623         spin_unlock(&sbi->inode_hash_lock);
 624         return inode;
 625 }
 626
 627 /* doesn't deal with root inode */
 628 static int exfat_fill_inode(struct inode *inode, struct exfat_dir_entry *info)
 629 {
 630         struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
 631         struct exfat_inode_info *ei = EXFAT_I(inode);
 632         loff_t size = info->size;
 633
 634         ei->dir = info->dir;
 635         ei->entry = info->entry;
 636         ei->attr = info->attr;
 637         ei->start_clu = info->start_clu;
 638         ei->flags = info->flags;
 639         ei->type = info->type;
 640         ei->valid_size = info->valid_size;
 641
 642         ei->version = 0;
 643         ei->hint_stat.eidx = 0;
 644         ei->hint_stat.clu = info->start_clu;
 645         ei->hint_femp.eidx = EXFAT_HINT_NONE;
 646         ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
 647         ei->i_pos = 0;
 648
 649         inode->i_uid = sbi->options.fs_uid;
 650         inode->i_gid = sbi->options.fs_gid;
 651         inode_inc_iversion(inode);
 652         inode->i_generation = get_random_u32();
 653
 654         if (info->attr & EXFAT_ATTR_SUBDIR) { /* directory */
 655                 inode->i_generation &= ~1;
 656                 inode->i_mode = exfat_make_mode(sbi, info->attr, 0777);
 657                 inode->i_op = &exfat_dir_inode_operations;
 658                 inode->i_fop = &exfat_dir_operations;
 659                 set_nlink(inode, info->num_subdirs);
 660         } else { /* regular file */
 661                 inode->i_generation |= 1;
 662                 inode->i_mode = exfat_make_mode(sbi, info->attr, 0777);
 663                 inode->i_op = &exfat_file_inode_operations;
 664                 inode->i_fop = &exfat_file_operations;
 665                 inode->i_mapping->a_ops = &exfat_aops;
 666                 inode->i_mapping->nrpages = 0;
 667         }
 668
 669         i_size_write(inode, size);
 670
 671         /* ondisk and aligned size should be aligned with block size */
 672         if (size & (inode->i_sb->s_blocksize - 1)) {
 673                 size |= (inode->i_sb->s_blocksize - 1);
 674                 size++;
 675         }
 676
 677         ei->i_size_aligned = size;
 678         ei->i_size_ondisk = size;
 679
 680         exfat_save_attr(inode, info->attr);
 681
 682         inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
 683         inode_set_mtime_to_ts(inode, info->mtime);
 684         inode_set_ctime_to_ts(inode, info->mtime);
 685         ei->i_crtime = info->crtime;
 686         inode_set_atime_to_ts(inode, info->atime);
 687
 688         return 0;
 689 }
 690
 691 struct inode *exfat_build_inode(struct super_block *sb,
 692                 struct exfat_dir_entry *info, loff_t i_pos)
 693 {
 694         struct inode *inode;
 695         int err;
 696
 697         inode = exfat_iget(sb, i_pos);
 698         if (inode)
 699                 goto out;
 700         inode = new_inode(sb);
 701         if (!inode) {
 702                 inode = ERR_PTR(-ENOMEM);
 703                 goto out;
 704         }
 705         inode->i_ino = iunique(sb, EXFAT_ROOT_INO);
 706         inode_set_iversion(inode, 1);
 707         err = exfat_fill_inode(inode, info);
 708         if (err) {
 709                 iput(inode);
 710                 inode = ERR_PTR(err);
 711                 goto out;
 712         }
 713         exfat_hash_inode(inode, i_pos);
 714         insert_inode_hash(inode);
 715 out:
 716         return inode;
 717 }
 718
 719 void exfat_evict_inode(struct inode *inode)
 720 {
 721         truncate_inode_pages(&inode->i_data, 0);
 722
 723         if (!inode->i_nlink) {
 724                 i_size_write(inode, 0);
 725                 mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
 726                 __exfat_truncate(inode);
 727                 mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
 728         }
 729
 730         invalidate_inode_buffers(inode);
 731         clear_inode(inode);
 732         exfat_cache_inval_inode(inode);
 733         exfat_unhash_inode(inode);
 734 }