summaryrefslogtreecommitdiff
path: root/fs/exfat/inode.c
blob: 0687f952956c34b6d85e785ee13f231d49679e64 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
 */

#include <linux/init.h>
#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/time.h>
#include <linux/writeback.h>
#include <linux/uio.h>
#include <linux/random.h>
#include <linux/iversion.h>

#include "exfat_raw.h"
#include "exfat_fs.h"

int __exfat_write_inode(struct inode *inode, int sync)
{
	unsigned long long on_disk_size;
	struct exfat_dentry *ep, *ep2;
	struct exfat_entry_set_cache es;
	struct super_block *sb = inode->i_sb;
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	struct exfat_inode_info *ei = EXFAT_I(inode);
	bool is_dir = (ei->type == TYPE_DIR) ? true : false;
	struct timespec64 ts;

	if (inode->i_ino == EXFAT_ROOT_INO)
		return 0;

	/*
	 * If the inode is already unlinked, there is no need for updating it.
	 */
	if (ei->dir.dir == DIR_DELETED)
		return 0;

	if (is_dir && ei->dir.dir == sbi->root_dir && ei->entry == -1)
		return 0;

	exfat_set_volume_dirty(sb);

	/* get the directory entry of given file or directory */
	if (exfat_get_dentry_set(&es, sb, &(ei->dir), ei->entry, ES_ALL_ENTRIES))
		return -EIO;
	ep = exfat_get_dentry_cached(&es, ES_IDX_FILE);
	ep2 = exfat_get_dentry_cached(&es, ES_IDX_STREAM);

	ep->dentry.file.attr = cpu_to_le16(exfat_make_attr(inode));

	/* set FILE_INFO structure using the acquired struct exfat_dentry */
	exfat_set_entry_time(sbi, &ei->i_crtime,
			&ep->dentry.file.create_tz,
			&ep->dentry.file.create_time,
			&ep->dentry.file.create_date,
			&ep->dentry.file.create_time_cs);
	ts = inode_get_mtime(inode);
	exfat_set_entry_time(sbi, &ts,
			     &ep->dentry.file.modify_tz,
			     &ep->dentry.file.modify_time,
			     &ep->dentry.file.modify_date,
			     &ep->dentry.file.modify_time_cs);
	ts = inode_get_atime(inode);
	exfat_set_entry_time(sbi, &ts,
			     &ep->dentry.file.access_tz,
			     &ep->dentry.file.access_time,
			     &ep->dentry.file.access_date,
			     NULL);

	/* File size should be zero if there is no cluster allocated */
	on_disk_size = i_size_read(inode);

	if (ei->start_clu == EXFAT_EOF_CLUSTER)
		on_disk_size = 0;

	ep2->dentry.stream.size = cpu_to_le64(on_disk_size);
	/*
	 * mmap write does not use exfat_write_end(), valid_size may be
	 * extended to the sector-aligned length in exfat_get_block().
	 * So we need to fixup valid_size to the writren length.
	 */
	if (on_disk_size < ei->valid_size)
		ep2->dentry.stream.valid_size = ep2->dentry.stream.size;
	else
		ep2->dentry.stream.valid_size = cpu_to_le64(ei->valid_size);

	if (on_disk_size) {
		ep2->dentry.stream.flags = ei->flags;
		ep2->dentry.stream.start_clu = cpu_to_le32(ei->start_clu);
	} else {
		ep2->dentry.stream.flags = ALLOC_FAT_CHAIN;
		ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER;
	}

	exfat_update_dir_chksum_with_entry_set(&es);
	return exfat_put_dentry_set(&es, sync);
}

int exfat_write_inode(struct inode *inode, struct writeback_control *wbc)
{
	int ret;

	mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
	ret = __exfat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
	mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);

	return ret;
}

void exfat_sync_inode(struct inode *inode)
{
	lockdep_assert_held(&EXFAT_SB(inode->i_sb)->s_lock);
	__exfat_write_inode(inode, 1);
}

/*
 * Input: inode, (logical) clu_offset, target allocation area
 * Output: errcode, cluster number
 * *clu = (~0), if it's unable to allocate a new cluster
 */
static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
		unsigned int *clu, int create)
{
	int ret;
	unsigned int last_clu;
	struct exfat_chain new_clu;
	struct super_block *sb = inode->i_sb;
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	struct exfat_inode_info *ei = EXFAT_I(inode);
	unsigned int local_clu_offset = clu_offset;
	unsigned int num_to_be_allocated = 0, num_clusters = 0;

	if (ei->i_size_ondisk > 0)
		num_clusters =
			EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi);

	if (clu_offset >= num_clusters)
		num_to_be_allocated = clu_offset - num_clusters + 1;

	if (!create && (num_to_be_allocated > 0)) {
		*clu = EXFAT_EOF_CLUSTER;
		return 0;
	}

	*clu = last_clu = ei->start_clu;

	if (ei->flags == ALLOC_NO_FAT_CHAIN) {
		if (clu_offset > 0 && *clu != EXFAT_EOF_CLUSTER) {
			last_clu += clu_offset - 1;

			if (clu_offset == num_clusters)
				*clu = EXFAT_EOF_CLUSTER;
			else
				*clu += clu_offset;
		}
	} else if (ei->type == TYPE_FILE) {
		unsigned int fclus = 0;
		int err = exfat_get_cluster(inode, clu_offset,
				&fclus, clu, &last_clu, 1);
		if (err)
			return -EIO;

		clu_offset -= fclus;
	} else {
		/* hint information */
		if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
		    ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
			clu_offset -= ei->hint_bmap.off;
			/* hint_bmap.clu should be valid */
			WARN_ON(ei->hint_bmap.clu < 2);
			*clu = ei->hint_bmap.clu;
		}

		while (clu_offset > 0 && *clu != EXFAT_EOF_CLUSTER) {
			last_clu = *clu;
			if (exfat_get_next_cluster(sb, clu))
				return -EIO;
			clu_offset--;
		}
	}

	if (*clu == EXFAT_EOF_CLUSTER) {
		exfat_set_volume_dirty(sb);

		new_clu.dir = (last_clu == EXFAT_EOF_CLUSTER) ?
				EXFAT_EOF_CLUSTER : last_clu + 1;
		new_clu.size = 0;
		new_clu.flags = ei->flags;

		/* allocate a cluster */
		if (num_to_be_allocated < 1) {
			/* Broken FAT (i_sze > allocated FAT) */
			exfat_fs_error(sb, "broken FAT chain.");
			return -EIO;
		}

		ret = exfat_alloc_cluster(inode, num_to_be_allocated, &new_clu,
				inode_needs_sync(inode));
		if (ret)
			return ret;

		if (new_clu.dir == EXFAT_EOF_CLUSTER ||
		    new_clu.dir == EXFAT_FREE_CLUSTER) {
			exfat_fs_error(sb,
				"bogus cluster new allocated (last_clu : %u, new_clu : %u)",
				last_clu, new_clu.dir);
			return -EIO;
		}

		/* append to the FAT chain */
		if (last_clu == EXFAT_EOF_CLUSTER) {
			if (new_clu.flags == ALLOC_FAT_CHAIN)
				ei->flags = ALLOC_FAT_CHAIN;
			ei->start_clu = new_clu.dir;
		} else {
			if (new_clu.flags != ei->flags) {
				/* no-fat-chain bit is disabled,
				 * so fat-chain should be synced with
				 * alloc-bitmap
				 */
				exfat_chain_cont_cluster(sb, ei->start_clu,
					num_clusters);
				ei->flags = ALLOC_FAT_CHAIN;
			}
			if (new_clu.flags == ALLOC_FAT_CHAIN)
				if (exfat_ent_set(sb, last_clu, new_clu.dir))
					return -EIO;
		}

		num_clusters += num_to_be_allocated;
		*clu = new_clu.dir;

		inode->i_blocks += EXFAT_CLU_TO_B(num_to_be_allocated, sbi) >> 9;

		/*
		 * Move *clu pointer along FAT chains (hole care) because the
		 * caller of this function expect *clu to be the last cluster.
		 * This only works when num_to_be_allocated >= 2,
		 * *clu = (the first cluster of the allocated chain) =>
		 * (the last cluster of ...)
		 */
		if (ei->flags == ALLOC_NO_FAT_CHAIN) {
			*clu += num_to_be_allocated - 1;
		} else {
			while (num_to_be_allocated > 1) {
				if (exfat_get_next_cluster(sb, clu))
					return -EIO;
				num_to_be_allocated--;
			}
		}

	}

	/* hint information */
	ei->hint_bmap.off = local_clu_offset;
	ei->hint_bmap.clu = *clu;

	return 0;
}

static int exfat_map_new_buffer(struct exfat_inode_info *ei,
		struct buffer_head *bh, loff_t pos)
{
	if (buffer_delay(bh) && pos > ei->i_size_aligned)
		return -EIO;
	set_buffer_new(bh);

	/*
	 * Adjust i_size_aligned if i_size_ondisk is bigger than it.
	 */
	if (ei->i_size_ondisk > ei->i_size_aligned)
		ei->i_size_aligned = ei->i_size_ondisk;
	return 0;
}

static int exfat_get_block(struct inode *inode, sector_t iblock,
		struct buffer_head *bh_result, int create)
{
	struct exfat_inode_info *ei = EXFAT_I(inode);
	struct super_block *sb = inode->i_sb;
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
	int err = 0;
	unsigned long mapped_blocks = 0;
	unsigned int cluster, sec_offset;
	sector_t last_block;
	sector_t phys = 0;
	sector_t valid_blks;
	loff_t pos;

	mutex_lock(&sbi->s_lock);
	last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size_read(inode), sb);
	if (iblock >= last_block && !create)
		goto done;

	/* Is this block already allocated? */
	err = exfat_map_cluster(inode, iblock >> sbi->sect_per_clus_bits,
			&cluster, create);
	if (err) {
		if (err != -ENOSPC)
			exfat_fs_error_ratelimit(sb,
				"failed to bmap (inode : %p iblock : %llu, err : %d)",
				inode, (unsigned long long)iblock, err);
		goto unlock_ret;
	}

	if (cluster == EXFAT_EOF_CLUSTER)
		goto done;

	/* sector offset in cluster */
	sec_offset = iblock & (sbi->sect_per_clus - 1);

	phys = exfat_cluster_to_sector(sbi, cluster) + sec_offset;
	mapped_blocks = sbi->sect_per_clus - sec_offset;
	max_blocks = min(mapped_blocks, max_blocks);

	pos = EXFAT_BLK_TO_B((iblock + 1), sb);
	if ((create && iblock >= last_block) || buffer_delay(bh_result)) {
		if (ei->i_size_ondisk < pos)
			ei->i_size_ondisk = pos;
	}

	map_bh(bh_result, sb, phys);
	if (buffer_delay(bh_result))
		clear_buffer_delay(bh_result);

	if (create) {
		valid_blks = EXFAT_B_TO_BLK_ROUND_UP(ei->valid_size, sb);

		if (iblock + max_blocks < valid_blks) {
			/* The range has been written, map it */
			goto done;
		} else if (iblock < valid_blks) {
			/*
			 * The range has been partially written,
			 * map the written part.
			 */
			max_blocks = valid_blks - iblock;
			goto done;
		}

		/* The area has not been written, map and mark as new. */
		err = exfat_map_new_buffer(ei, bh_result, pos);
		if (err) {
			exfat_fs_error(sb,
					"requested for bmap out of range(pos : (%llu) > i_size_aligned(%llu)\n",
					pos, ei->i_size_aligned);
			goto unlock_ret;
		}

		ei->valid_size = EXFAT_BLK_TO_B(iblock + max_blocks, sb);
		mark_inode_dirty(inode);
	} else {
		valid_blks = EXFAT_B_TO_BLK(ei->valid_size, sb);

		if (iblock + max_blocks < valid_blks) {
			/* The range has been written, map it */
			goto done;
		} else if (iblock < valid_blks) {
			/*
			 * The area has been partially written,
			 * map the written part.
			 */
			max_blocks = valid_blks - iblock;
			goto done;
		} else if (iblock == valid_blks &&
			   (ei->valid_size & (sb->s_blocksize - 1))) {
			/*
			 * The block has been partially written,
			 * zero the unwritten part and map the block.
			 */
			loff_t size, off;

			max_blocks = 1;

			/*
			 * For direct read, the unwritten part will be zeroed in
			 * exfat_direct_IO()
			 */
			if (!bh_result->b_folio)
				goto done;

			pos -= sb->s_blocksize;
			size = ei->valid_size - pos;
			off = pos & (PAGE_SIZE - 1);

			folio_set_bh(bh_result, bh_result->b_folio, off);
			err = bh_read(bh_result, 0);
			if (err < 0)
				goto unlock_ret;

			folio_zero_segment(bh_result->b_folio, off + size,
					off + sb->s_blocksize);
		} else {
			/*
			 * The range has not been written, clear the mapped flag
			 * to only zero the cache and do not read from disk.
			 */
			clear_buffer_mapped(bh_result);
		}
	}
done:
	bh_result->b_size = EXFAT_BLK_TO_B(max_blocks, sb);
unlock_ret:
	mutex_unlock(&sbi->s_lock);
	return err;
}

static int exfat_read_folio(struct file *file, struct folio *folio)
{
	return mpage_read_folio(folio, exfat_get_block);
}

static void exfat_readahead(struct readahead_control *rac)
{
	struct address_space *mapping = rac->mapping;
	struct inode *inode = mapping->host;
	struct exfat_inode_info *ei = EXFAT_I(inode);
	loff_t pos = readahead_pos(rac);

	/* Range cross valid_size, read it page by page. */
	if (ei->valid_size < i_size_read(inode) &&
	    pos <= ei->valid_size &&
	    ei->valid_size < pos + readahead_length(rac))
		return;

	mpage_readahead(rac, exfat_get_block);
}

static int exfat_writepages(struct address_space *mapping,
		struct writeback_control *wbc)
{
	return mpage_writepages(mapping, wbc, exfat_get_block);
}

static void exfat_write_failed(struct address_space *mapping, loff_t to)
{
	struct inode *inode = mapping->host;

	if (to > i_size_read(inode)) {
		truncate_pagecache(inode, i_size_read(inode));
		inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
		exfat_truncate(inode);
	}
}

static int exfat_write_begin(struct file *file, struct address_space *mapping,
		loff_t pos, unsigned int len,
		struct page **pagep, void **fsdata)
{
	int ret;

	*pagep = NULL;
	ret = block_write_begin(mapping, pos, len, pagep, exfat_get_block);

	if (ret < 0)
		exfat_write_failed(mapping, pos+len);

	return ret;
}

static int exfat_write_end(struct file *file, struct address_space *mapping,
		loff_t pos, unsigned int len, unsigned int copied,
		struct page *pagep, void *fsdata)
{
	struct inode *inode = mapping->host;
	struct exfat_inode_info *ei = EXFAT_I(inode);
	int err;

	err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);

	if (ei->i_size_aligned < i_size_read(inode)) {
		exfat_fs_error(inode->i_sb,
			"invalid size(size(%llu) > aligned(%llu)\n",
			i_size_read(inode), ei->i_size_aligned);
		return -EIO;
	}

	if (err < len)
		exfat_write_failed(mapping, pos+len);

	if (!(err < 0) && pos + err > ei->valid_size) {
		ei->valid_size = pos + err;
		mark_inode_dirty(inode);
	}

	if (!(err < 0) && !(ei->attr & EXFAT_ATTR_ARCHIVE)) {
		inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
		ei->attr |= EXFAT_ATTR_ARCHIVE;
		mark_inode_dirty(inode);
	}

	return err;
}

static ssize_t exfat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
{
	struct address_space *mapping = iocb->ki_filp->f_mapping;
	struct inode *inode = mapping->host;
	struct exfat_inode_info *ei = EXFAT_I(inode);
	loff_t pos = iocb->ki_pos;
	loff_t size = pos + iov_iter_count(iter);
	int rw = iov_iter_rw(iter);
	ssize_t ret;

	if (rw == WRITE) {
		/*
		 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
		 * so we need to update the ->i_size_aligned to block boundary.
		 *
		 * But we must fill the remaining area or hole by nul for
		 * updating ->i_size_aligned
		 *
		 * Return 0, and fallback to normal buffered write.
		 */
		if (EXFAT_I(inode)->i_size_aligned < size)
			return 0;
	}

	/*
	 * Need to use the DIO_LOCKING for avoiding the race
	 * condition of exfat_get_block() and ->truncate().
	 */
	ret = blockdev_direct_IO(iocb, inode, iter, exfat_get_block);
	if (ret < 0) {
		if (rw == WRITE && ret != -EIOCBQUEUED)
			exfat_write_failed(mapping, size);

		return ret;
	} else
		size = pos + ret;

	/* zero the unwritten part in the partially written block */
	if (rw == READ && pos < ei->valid_size && ei->valid_size < size) {
		iov_iter_revert(iter, size - ei->valid_size);
		iov_iter_zero(size - ei->valid_size, iter);
	}

	return ret;
}

static sector_t exfat_aop_bmap(struct address_space *mapping, sector_t block)
{
	sector_t blocknr;

	/* exfat_get_cluster() assumes the requested blocknr isn't truncated. */
	down_read(&EXFAT_I(mapping->host)->truncate_lock);
	blocknr = generic_block_bmap(mapping, block, exfat_get_block);
	up_read(&EXFAT_I(mapping->host)->truncate_lock);
	return blocknr;
}

/*
 * exfat_block_truncate_page() zeroes out a mapping from file offset `from'
 * up to the end of the block which corresponds to `from'.
 * This is required during truncate to physically zeroout the tail end
 * of that block so it doesn't yield old data if the file is later grown.
 * Also, avoid causing failure from fsx for cases of "data past EOF"
 */
int exfat_block_truncate_page(struct inode *inode, loff_t from)
{
	return block_truncate_page(inode->i_mapping, from, exfat_get_block);
}

static const struct address_space_operations exfat_aops = {
	.dirty_folio	= block_dirty_folio,
	.invalidate_folio = block_invalidate_folio,
	.read_folio	= exfat_read_folio,
	.readahead	= exfat_readahead,
	.writepages	= exfat_writepages,
	.write_begin	= exfat_write_begin,
	.write_end	= exfat_write_end,
	.direct_IO	= exfat_direct_IO,
	.bmap		= exfat_aop_bmap,
	.migrate_folio	= buffer_migrate_folio,
};

static inline unsigned long exfat_hash(loff_t i_pos)
{
	return hash_32(i_pos, EXFAT_HASH_BITS);
}

void exfat_hash_inode(struct inode *inode, loff_t i_pos)
{
	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
	struct hlist_head *head = sbi->inode_hashtable + exfat_hash(i_pos);

	spin_lock(&sbi->inode_hash_lock);
	EXFAT_I(inode)->i_pos = i_pos;
	hlist_add_head(&EXFAT_I(inode)->i_hash_fat, head);
	spin_unlock(&sbi->inode_hash_lock);
}

void exfat_unhash_inode(struct inode *inode)
{
	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);

	spin_lock(&sbi->inode_hash_lock);
	hlist_del_init(&EXFAT_I(inode)->i_hash_fat);
	EXFAT_I(inode)->i_pos = 0;
	spin_unlock(&sbi->inode_hash_lock);
}

struct inode *exfat_iget(struct super_block *sb, loff_t i_pos)
{
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	struct exfat_inode_info *info;
	struct hlist_head *head = sbi->inode_hashtable + exfat_hash(i_pos);
	struct inode *inode = NULL;

	spin_lock(&sbi->inode_hash_lock);
	hlist_for_each_entry(info, head, i_hash_fat) {
		WARN_ON(info->vfs_inode.i_sb != sb);

		if (i_pos != info->i_pos)
			continue;
		inode = igrab(&info->vfs_inode);
		if (inode)
			break;
	}
	spin_unlock(&sbi->inode_hash_lock);
	return inode;
}

/* doesn't deal with root inode */
static int exfat_fill_inode(struct inode *inode, struct exfat_dir_entry *info)
{
	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
	struct exfat_inode_info *ei = EXFAT_I(inode);
	loff_t size = info->size;

	ei->dir = info->dir;
	ei->entry = info->entry;
	ei->attr = info->attr;
	ei->start_clu = info->start_clu;
	ei->flags = info->flags;
	ei->type = info->type;
	ei->valid_size = info->valid_size;

	ei->version = 0;
	ei->hint_stat.eidx = 0;
	ei->hint_stat.clu = info->start_clu;
	ei->hint_femp.eidx = EXFAT_HINT_NONE;
	ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
	ei->i_pos = 0;

	inode->i_uid = sbi->options.fs_uid;
	inode->i_gid = sbi->options.fs_gid;
	inode_inc_iversion(inode);
	inode->i_generation = get_random_u32();

	if (info->attr & EXFAT_ATTR_SUBDIR) { /* directory */
		inode->i_generation &= ~1;
		inode->i_mode = exfat_make_mode(sbi, info->attr, 0777);
		inode->i_op = &exfat_dir_inode_operations;
		inode->i_fop = &exfat_dir_operations;
		set_nlink(inode, info->num_subdirs);
	} else { /* regular file */
		inode->i_generation |= 1;
		inode->i_mode = exfat_make_mode(sbi, info->attr, 0777);
		inode->i_op = &exfat_file_inode_operations;
		inode->i_fop = &exfat_file_operations;
		inode->i_mapping->a_ops = &exfat_aops;
		inode->i_mapping->nrpages = 0;
	}

	i_size_write(inode, size);

	/* ondisk and aligned size should be aligned with block size */
	if (size & (inode->i_sb->s_blocksize - 1)) {
		size |= (inode->i_sb->s_blocksize - 1);
		size++;
	}

	ei->i_size_aligned = size;
	ei->i_size_ondisk = size;

	exfat_save_attr(inode, info->attr);

	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
	inode_set_mtime_to_ts(inode, info->mtime);
	inode_set_ctime_to_ts(inode, info->mtime);
	ei->i_crtime = info->crtime;
	inode_set_atime_to_ts(inode, info->atime);

	return 0;
}

struct inode *exfat_build_inode(struct super_block *sb,
		struct exfat_dir_entry *info, loff_t i_pos)
{
	struct inode *inode;
	int err;

	inode = exfat_iget(sb, i_pos);
	if (inode)
		goto out;
	inode = new_inode(sb);
	if (!inode) {
		inode = ERR_PTR(-ENOMEM);
		goto out;
	}
	inode->i_ino = iunique(sb, EXFAT_ROOT_INO);
	inode_set_iversion(inode, 1);
	err = exfat_fill_inode(inode, info);
	if (err) {
		iput(inode);
		inode = ERR_PTR(err);
		goto out;
	}
	exfat_hash_inode(inode, i_pos);
	insert_inode_hash(inode);
out:
	return inode;
}

void exfat_evict_inode(struct inode *inode)
{
	truncate_inode_pages(&inode->i_data, 0);

	if (!inode->i_nlink) {
		i_size_write(inode, 0);
		mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
		__exfat_truncate(inode);
		mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
	}

	invalidate_inode_buffers(inode);
	clear_inode(inode);
	exfat_cache_inval_inode(inode);
	exfat_unhash_inode(inode);
}