summaryrefslogtreecommitdiff
path: root/fs/xfs/scrub/dir.c
blob: 7c432997edade4ee1356449e47aeb32cf38346ec (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
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2017 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <darrick.wong@oracle.com>
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_inode.h"
#include "xfs_icache.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/dabtree.h"

/* Set us up to scrub directories. */
int
xchk_setup_directory(
	struct xfs_scrub	*sc,
	struct xfs_inode	*ip)
{
	return xchk_setup_inode_contents(sc, ip, 0);
}

/* Directories */

/* Scrub a directory entry. */

struct xchk_dir_ctx {
	/* VFS fill-directory iterator */
	struct dir_context	dir_iter;

	struct xfs_scrub	*sc;
};

/* Check that an inode's mode matches a given DT_ type. */
STATIC int
xchk_dir_check_ftype(
	struct xchk_dir_ctx	*sdc,
	xfs_fileoff_t		offset,
	xfs_ino_t		inum,
	int			dtype)
{
	struct xfs_mount	*mp = sdc->sc->mp;
	struct xfs_inode	*ip;
	int			ino_dtype;
	int			error = 0;

	if (!xfs_sb_version_hasftype(&mp->m_sb)) {
		if (dtype != DT_UNKNOWN && dtype != DT_DIR)
			xchk_fblock_set_corrupt(sdc->sc, XFS_DATA_FORK,
					offset);
		goto out;
	}

	/*
	 * Grab the inode pointed to by the dirent.  We release the
	 * inode before we cancel the scrub transaction.  Since we're
	 * don't know a priori that releasing the inode won't trigger
	 * eofblocks cleanup (which allocates what would be a nested
	 * transaction), we can't use DONTCACHE here because DONTCACHE
	 * inodes can trigger immediate inactive cleanup of the inode.
	 */
	error = xfs_iget(mp, sdc->sc->tp, inum, 0, 0, &ip);
	if (!xchk_fblock_xref_process_error(sdc->sc, XFS_DATA_FORK, offset,
			&error))
		goto out;

	/* Convert mode to the DT_* values that dir_emit uses. */
	ino_dtype = xfs_dir3_get_dtype(mp,
			xfs_mode_to_ftype(VFS_I(ip)->i_mode));
	if (ino_dtype != dtype)
		xchk_fblock_set_corrupt(sdc->sc, XFS_DATA_FORK, offset);
	xfs_irele(ip);
out:
	return error;
}

/*
 * Scrub a single directory entry.
 *
 * We use the VFS directory iterator (i.e. readdir) to call this
 * function for every directory entry in a directory.  Once we're here,
 * we check the inode number to make sure it's sane, then we check that
 * we can look up this filename.  Finally, we check the ftype.
 */
STATIC int
xchk_dir_actor(
	struct dir_context	*dir_iter,
	const char		*name,
	int			namelen,
	loff_t			pos,
	u64			ino,
	unsigned		type)
{
	struct xfs_mount	*mp;
	struct xfs_inode	*ip;
	struct xchk_dir_ctx	*sdc;
	struct xfs_name		xname;
	xfs_ino_t		lookup_ino;
	xfs_dablk_t		offset;
	int			error = 0;

	sdc = container_of(dir_iter, struct xchk_dir_ctx, dir_iter);
	ip = sdc->sc->ip;
	mp = ip->i_mount;
	offset = xfs_dir2_db_to_da(mp->m_dir_geo,
			xfs_dir2_dataptr_to_db(mp->m_dir_geo, pos));

	if (xchk_should_terminate(sdc->sc, &error))
		return error;

	/* Does this inode number make sense? */
	if (!xfs_verify_dir_ino(mp, ino)) {
		xchk_fblock_set_corrupt(sdc->sc, XFS_DATA_FORK, offset);
		goto out;
	}

	/* Does this name make sense? */
	if (!xfs_dir2_namecheck(name, namelen)) {
		xchk_fblock_set_corrupt(sdc->sc, XFS_DATA_FORK, offset);
		goto out;
	}

	if (!strncmp(".", name, namelen)) {
		/* If this is "." then check that the inum matches the dir. */
		if (xfs_sb_version_hasftype(&mp->m_sb) && type != DT_DIR)
			xchk_fblock_set_corrupt(sdc->sc, XFS_DATA_FORK,
					offset);
		if (ino != ip->i_ino)
			xchk_fblock_set_corrupt(sdc->sc, XFS_DATA_FORK,
					offset);
	} else if (!strncmp("..", name, namelen)) {
		/*
		 * If this is ".." in the root inode, check that the inum
		 * matches this dir.
		 */
		if (xfs_sb_version_hasftype(&mp->m_sb) && type != DT_DIR)
			xchk_fblock_set_corrupt(sdc->sc, XFS_DATA_FORK,
					offset);
		if (ip->i_ino == mp->m_sb.sb_rootino && ino != ip->i_ino)
			xchk_fblock_set_corrupt(sdc->sc, XFS_DATA_FORK,
					offset);
	}

	/* Verify that we can look up this name by hash. */
	xname.name = name;
	xname.len = namelen;
	xname.type = XFS_DIR3_FT_UNKNOWN;

	error = xfs_dir_lookup(sdc->sc->tp, ip, &xname, &lookup_ino, NULL);
	/* ENOENT means the hash lookup failed and the dir is corrupt */
	if (error == -ENOENT)
		error = -EFSCORRUPTED;
	if (!xchk_fblock_process_error(sdc->sc, XFS_DATA_FORK, offset,
			&error))
		goto out;
	if (lookup_ino != ino) {
		xchk_fblock_set_corrupt(sdc->sc, XFS_DATA_FORK, offset);
		goto out;
	}

	/* Verify the file type.  This function absorbs error codes. */
	error = xchk_dir_check_ftype(sdc, offset, lookup_ino, type);
	if (error)
		goto out;
out:
	/*
	 * A negative error code returned here is supposed to cause the
	 * dir_emit caller (xfs_readdir) to abort the directory iteration
	 * and return zero to xchk_directory.
	 */
	if (error == 0 && sdc->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
		return -EFSCORRUPTED;
	return error;
}

/* Scrub a directory btree record. */
STATIC int
xchk_dir_rec(
	struct xchk_da_btree		*ds,
	int				level)
{
	struct xfs_da_state_blk		*blk = &ds->state->path.blk[level];
	struct xfs_mount		*mp = ds->state->mp;
	struct xfs_inode		*dp = ds->dargs.dp;
	struct xfs_da_geometry		*geo = mp->m_dir_geo;
	struct xfs_dir2_data_entry	*dent;
	struct xfs_buf			*bp;
	struct xfs_dir2_leaf_entry	*ent;
	unsigned int			end;
	unsigned int			iter_off;
	xfs_ino_t			ino;
	xfs_dablk_t			rec_bno;
	xfs_dir2_db_t			db;
	xfs_dir2_data_aoff_t		off;
	xfs_dir2_dataptr_t		ptr;
	xfs_dahash_t			calc_hash;
	xfs_dahash_t			hash;
	struct xfs_dir3_icleaf_hdr	hdr;
	unsigned int			tag;
	int				error;

	ASSERT(blk->magic == XFS_DIR2_LEAF1_MAGIC ||
	       blk->magic == XFS_DIR2_LEAFN_MAGIC);

	xfs_dir2_leaf_hdr_from_disk(mp, &hdr, blk->bp->b_addr);
	ent = hdr.ents + blk->index;

	/* Check the hash of the entry. */
	error = xchk_da_btree_hash(ds, level, &ent->hashval);
	if (error)
		goto out;

	/* Valid hash pointer? */
	ptr = be32_to_cpu(ent->address);
	if (ptr == 0)
		return 0;

	/* Find the directory entry's location. */
	db = xfs_dir2_dataptr_to_db(geo, ptr);
	off = xfs_dir2_dataptr_to_off(geo, ptr);
	rec_bno = xfs_dir2_db_to_da(geo, db);

	if (rec_bno >= geo->leafblk) {
		xchk_da_set_corrupt(ds, level);
		goto out;
	}
	error = xfs_dir3_data_read(ds->dargs.trans, dp, rec_bno,
			XFS_DABUF_MAP_HOLE_OK, &bp);
	if (!xchk_fblock_process_error(ds->sc, XFS_DATA_FORK, rec_bno,
			&error))
		goto out;
	if (!bp) {
		xchk_fblock_set_corrupt(ds->sc, XFS_DATA_FORK, rec_bno);
		goto out;
	}
	xchk_buffer_recheck(ds->sc, bp);

	if (ds->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
		goto out_relse;

	dent = bp->b_addr + off;

	/* Make sure we got a real directory entry. */
	iter_off = geo->data_entry_offset;
	end = xfs_dir3_data_end_offset(geo, bp->b_addr);
	if (!end) {
		xchk_fblock_set_corrupt(ds->sc, XFS_DATA_FORK, rec_bno);
		goto out_relse;
	}
	for (;;) {
		struct xfs_dir2_data_entry	*dep = bp->b_addr + iter_off;
		struct xfs_dir2_data_unused	*dup = bp->b_addr + iter_off;

		if (iter_off >= end) {
			xchk_fblock_set_corrupt(ds->sc, XFS_DATA_FORK, rec_bno);
			goto out_relse;
		}

		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
			iter_off += be16_to_cpu(dup->length);
			continue;
		}
		if (dep == dent)
			break;
		iter_off += xfs_dir2_data_entsize(mp, dep->namelen);
	}

	/* Retrieve the entry, sanity check it, and compare hashes. */
	ino = be64_to_cpu(dent->inumber);
	hash = be32_to_cpu(ent->hashval);
	tag = be16_to_cpup(xfs_dir2_data_entry_tag_p(mp, dent));
	if (!xfs_verify_dir_ino(mp, ino) || tag != off)
		xchk_fblock_set_corrupt(ds->sc, XFS_DATA_FORK, rec_bno);
	if (dent->namelen == 0) {
		xchk_fblock_set_corrupt(ds->sc, XFS_DATA_FORK, rec_bno);
		goto out_relse;
	}
	calc_hash = xfs_da_hashname(dent->name, dent->namelen);
	if (calc_hash != hash)
		xchk_fblock_set_corrupt(ds->sc, XFS_DATA_FORK, rec_bno);

out_relse:
	xfs_trans_brelse(ds->dargs.trans, bp);
out:
	return error;
}

/*
 * Is this unused entry either in the bestfree or smaller than all of
 * them?  We've already checked that the bestfrees are sorted longest to
 * shortest, and that there aren't any bogus entries.
 */
STATIC void
xchk_directory_check_free_entry(
	struct xfs_scrub		*sc,
	xfs_dablk_t			lblk,
	struct xfs_dir2_data_free	*bf,
	struct xfs_dir2_data_unused	*dup)
{
	struct xfs_dir2_data_free	*dfp;
	unsigned int			dup_length;

	dup_length = be16_to_cpu(dup->length);

	/* Unused entry is shorter than any of the bestfrees */
	if (dup_length < be16_to_cpu(bf[XFS_DIR2_DATA_FD_COUNT - 1].length))
		return;

	for (dfp = &bf[XFS_DIR2_DATA_FD_COUNT - 1]; dfp >= bf; dfp--)
		if (dup_length == be16_to_cpu(dfp->length))
			return;

	/* Unused entry should be in the bestfrees but wasn't found. */
	xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
}

/* Check free space info in a directory data block. */
STATIC int
xchk_directory_data_bestfree(
	struct xfs_scrub		*sc,
	xfs_dablk_t			lblk,
	bool				is_block)
{
	struct xfs_dir2_data_unused	*dup;
	struct xfs_dir2_data_free	*dfp;
	struct xfs_buf			*bp;
	struct xfs_dir2_data_free	*bf;
	struct xfs_mount		*mp = sc->mp;
	u16				tag;
	unsigned int			nr_bestfrees = 0;
	unsigned int			nr_frees = 0;
	unsigned int			smallest_bestfree;
	int				newlen;
	unsigned int			offset;
	unsigned int			end;
	int				error;

	if (is_block) {
		/* dir block format */
		if (lblk != XFS_B_TO_FSBT(mp, XFS_DIR2_DATA_OFFSET))
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
		error = xfs_dir3_block_read(sc->tp, sc->ip, &bp);
	} else {
		/* dir data format */
		error = xfs_dir3_data_read(sc->tp, sc->ip, lblk, 0, &bp);
	}
	if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, lblk, &error))
		goto out;
	xchk_buffer_recheck(sc, bp);

	/* XXX: Check xfs_dir3_data_hdr.pad is zero once we start setting it. */

	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
		goto out_buf;

	/* Do the bestfrees correspond to actual free space? */
	bf = xfs_dir2_data_bestfree_p(mp, bp->b_addr);
	smallest_bestfree = UINT_MAX;
	for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
		offset = be16_to_cpu(dfp->offset);
		if (offset == 0)
			continue;
		if (offset >= mp->m_dir_geo->blksize) {
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
			goto out_buf;
		}
		dup = bp->b_addr + offset;
		tag = be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup));

		/* bestfree doesn't match the entry it points at? */
		if (dup->freetag != cpu_to_be16(XFS_DIR2_DATA_FREE_TAG) ||
		    be16_to_cpu(dup->length) != be16_to_cpu(dfp->length) ||
		    tag != offset) {
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
			goto out_buf;
		}

		/* bestfree records should be ordered largest to smallest */
		if (smallest_bestfree < be16_to_cpu(dfp->length)) {
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
			goto out_buf;
		}

		smallest_bestfree = be16_to_cpu(dfp->length);
		nr_bestfrees++;
	}

	/* Make sure the bestfrees are actually the best free spaces. */
	offset = mp->m_dir_geo->data_entry_offset;
	end = xfs_dir3_data_end_offset(mp->m_dir_geo, bp->b_addr);

	/* Iterate the entries, stopping when we hit or go past the end. */
	while (offset < end) {
		dup = bp->b_addr + offset;

		/* Skip real entries */
		if (dup->freetag != cpu_to_be16(XFS_DIR2_DATA_FREE_TAG)) {
			struct xfs_dir2_data_entry *dep = bp->b_addr + offset;

			newlen = xfs_dir2_data_entsize(mp, dep->namelen);
			if (newlen <= 0) {
				xchk_fblock_set_corrupt(sc, XFS_DATA_FORK,
						lblk);
				goto out_buf;
			}
			offset += newlen;
			continue;
		}

		/* Spot check this free entry */
		tag = be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup));
		if (tag != offset) {
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
			goto out_buf;
		}

		/*
		 * Either this entry is a bestfree or it's smaller than
		 * any of the bestfrees.
		 */
		xchk_directory_check_free_entry(sc, lblk, bf, dup);
		if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
			goto out_buf;

		/* Move on. */
		newlen = be16_to_cpu(dup->length);
		if (newlen <= 0) {
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
			goto out_buf;
		}
		offset += newlen;
		if (offset <= end)
			nr_frees++;
	}

	/* We're required to fill all the space. */
	if (offset != end)
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);

	/* Did we see at least as many free slots as there are bestfrees? */
	if (nr_frees < nr_bestfrees)
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
out_buf:
	xfs_trans_brelse(sc->tp, bp);
out:
	return error;
}

/*
 * Does the free space length in the free space index block ($len) match
 * the longest length in the directory data block's bestfree array?
 * Assume that we've already checked that the data block's bestfree
 * array is in order.
 */
STATIC void
xchk_directory_check_freesp(
	struct xfs_scrub		*sc,
	xfs_dablk_t			lblk,
	struct xfs_buf			*dbp,
	unsigned int			len)
{
	struct xfs_dir2_data_free	*dfp;

	dfp = xfs_dir2_data_bestfree_p(sc->mp, dbp->b_addr);

	if (len != be16_to_cpu(dfp->length))
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);

	if (len > 0 && be16_to_cpu(dfp->offset) == 0)
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
}

/* Check free space info in a directory leaf1 block. */
STATIC int
xchk_directory_leaf1_bestfree(
	struct xfs_scrub		*sc,
	struct xfs_da_args		*args,
	xfs_dablk_t			lblk)
{
	struct xfs_dir3_icleaf_hdr	leafhdr;
	struct xfs_dir2_leaf_tail	*ltp;
	struct xfs_dir2_leaf		*leaf;
	struct xfs_buf			*dbp;
	struct xfs_buf			*bp;
	struct xfs_da_geometry		*geo = sc->mp->m_dir_geo;
	__be16				*bestp;
	__u16				best;
	__u32				hash;
	__u32				lasthash = 0;
	__u32				bestcount;
	unsigned int			stale = 0;
	int				i;
	int				error;

	/* Read the free space block. */
	error = xfs_dir3_leaf_read(sc->tp, sc->ip, lblk, &bp);
	if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, lblk, &error))
		return error;
	xchk_buffer_recheck(sc, bp);

	leaf = bp->b_addr;
	xfs_dir2_leaf_hdr_from_disk(sc->ip->i_mount, &leafhdr, leaf);
	ltp = xfs_dir2_leaf_tail_p(geo, leaf);
	bestcount = be32_to_cpu(ltp->bestcount);
	bestp = xfs_dir2_leaf_bests_p(ltp);

	if (xfs_sb_version_hascrc(&sc->mp->m_sb)) {
		struct xfs_dir3_leaf_hdr	*hdr3 = bp->b_addr;

		if (hdr3->pad != cpu_to_be32(0))
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
	}

	/*
	 * There should be as many bestfree slots as there are dir data
	 * blocks that can fit under i_size.
	 */
	if (bestcount != xfs_dir2_byte_to_db(geo, sc->ip->i_d.di_size)) {
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
		goto out;
	}

	/* Is the leaf count even remotely sane? */
	if (leafhdr.count > geo->leaf_max_ents) {
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
		goto out;
	}

	/* Leaves and bests don't overlap in leaf format. */
	if ((char *)&leafhdr.ents[leafhdr.count] > (char *)bestp) {
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
		goto out;
	}

	/* Check hash value order, count stale entries.  */
	for (i = 0; i < leafhdr.count; i++) {
		hash = be32_to_cpu(leafhdr.ents[i].hashval);
		if (i > 0 && lasthash > hash)
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
		lasthash = hash;
		if (leafhdr.ents[i].address ==
		    cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
			stale++;
	}
	if (leafhdr.stale != stale)
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
		goto out;

	/* Check all the bestfree entries. */
	for (i = 0; i < bestcount; i++, bestp++) {
		best = be16_to_cpu(*bestp);
		if (best == NULLDATAOFF)
			continue;
		error = xfs_dir3_data_read(sc->tp, sc->ip,
				i * args->geo->fsbcount, 0, &dbp);
		if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, lblk,
				&error))
			break;
		xchk_directory_check_freesp(sc, lblk, dbp, best);
		xfs_trans_brelse(sc->tp, dbp);
		if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
			break;
	}
out:
	xfs_trans_brelse(sc->tp, bp);
	return error;
}

/* Check free space info in a directory freespace block. */
STATIC int
xchk_directory_free_bestfree(
	struct xfs_scrub		*sc,
	struct xfs_da_args		*args,
	xfs_dablk_t			lblk)
{
	struct xfs_dir3_icfree_hdr	freehdr;
	struct xfs_buf			*dbp;
	struct xfs_buf			*bp;
	__u16				best;
	unsigned int			stale = 0;
	int				i;
	int				error;

	/* Read the free space block */
	error = xfs_dir2_free_read(sc->tp, sc->ip, lblk, &bp);
	if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, lblk, &error))
		return error;
	xchk_buffer_recheck(sc, bp);

	if (xfs_sb_version_hascrc(&sc->mp->m_sb)) {
		struct xfs_dir3_free_hdr	*hdr3 = bp->b_addr;

		if (hdr3->pad != cpu_to_be32(0))
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
	}

	/* Check all the entries. */
	xfs_dir2_free_hdr_from_disk(sc->ip->i_mount, &freehdr, bp->b_addr);
	for (i = 0; i < freehdr.nvalid; i++) {
		best = be16_to_cpu(freehdr.bests[i]);
		if (best == NULLDATAOFF) {
			stale++;
			continue;
		}
		error = xfs_dir3_data_read(sc->tp, sc->ip,
				(freehdr.firstdb + i) * args->geo->fsbcount,
				0, &dbp);
		if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, lblk,
				&error))
			goto out;
		xchk_directory_check_freesp(sc, lblk, dbp, best);
		xfs_trans_brelse(sc->tp, dbp);
	}

	if (freehdr.nused + stale != freehdr.nvalid)
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
out:
	xfs_trans_brelse(sc->tp, bp);
	return error;
}

/* Check free space information in directories. */
STATIC int
xchk_directory_blocks(
	struct xfs_scrub	*sc)
{
	struct xfs_bmbt_irec	got;
	struct xfs_da_args	args;
	struct xfs_ifork	*ifp = XFS_IFORK_PTR(sc->ip, XFS_DATA_FORK);
	struct xfs_mount	*mp = sc->mp;
	xfs_fileoff_t		leaf_lblk;
	xfs_fileoff_t		free_lblk;
	xfs_fileoff_t		lblk;
	struct xfs_iext_cursor	icur;
	xfs_dablk_t		dabno;
	bool			found;
	int			is_block = 0;
	int			error;

	/* Ignore local format directories. */
	if (ifp->if_format != XFS_DINODE_FMT_EXTENTS &&
	    ifp->if_format != XFS_DINODE_FMT_BTREE)
		return 0;

	lblk = XFS_B_TO_FSB(mp, XFS_DIR2_DATA_OFFSET);
	leaf_lblk = XFS_B_TO_FSB(mp, XFS_DIR2_LEAF_OFFSET);
	free_lblk = XFS_B_TO_FSB(mp, XFS_DIR2_FREE_OFFSET);

	/* Is this a block dir? */
	args.dp = sc->ip;
	args.geo = mp->m_dir_geo;
	args.trans = sc->tp;
	error = xfs_dir2_isblock(&args, &is_block);
	if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, lblk, &error))
		goto out;

	/* Iterate all the data extents in the directory... */
	found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &icur, &got);
	while (found && !(sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)) {
		/* Block directories only have a single block at offset 0. */
		if (is_block &&
		    (got.br_startoff > 0 ||
		     got.br_blockcount != args.geo->fsbcount)) {
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK,
					got.br_startoff);
			break;
		}

		/* No more data blocks... */
		if (got.br_startoff >= leaf_lblk)
			break;

		/*
		 * Check each data block's bestfree data.
		 *
		 * Iterate all the fsbcount-aligned block offsets in
		 * this directory.  The directory block reading code is
		 * smart enough to do its own bmap lookups to handle
		 * discontiguous directory blocks.  When we're done
		 * with the extent record, re-query the bmap at the
		 * next fsbcount-aligned offset to avoid redundant
		 * block checks.
		 */
		for (lblk = roundup((xfs_dablk_t)got.br_startoff,
				args.geo->fsbcount);
		     lblk < got.br_startoff + got.br_blockcount;
		     lblk += args.geo->fsbcount) {
			error = xchk_directory_data_bestfree(sc, lblk,
					is_block);
			if (error)
				goto out;
		}
		dabno = got.br_startoff + got.br_blockcount;
		lblk = roundup(dabno, args.geo->fsbcount);
		found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &icur, &got);
	}

	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
		goto out;

	/* Look for a leaf1 block, which has free info. */
	if (xfs_iext_lookup_extent(sc->ip, ifp, leaf_lblk, &icur, &got) &&
	    got.br_startoff == leaf_lblk &&
	    got.br_blockcount == args.geo->fsbcount &&
	    !xfs_iext_next_extent(ifp, &icur, &got)) {
		if (is_block) {
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
			goto out;
		}
		error = xchk_directory_leaf1_bestfree(sc, &args,
				leaf_lblk);
		if (error)
			goto out;
	}

	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
		goto out;

	/* Scan for free blocks */
	lblk = free_lblk;
	found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &icur, &got);
	while (found && !(sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)) {
		/*
		 * Dirs can't have blocks mapped above 2^32.
		 * Single-block dirs shouldn't even be here.
		 */
		lblk = got.br_startoff;
		if (lblk & ~0xFFFFFFFFULL) {
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
			goto out;
		}
		if (is_block) {
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
			goto out;
		}

		/*
		 * Check each dir free block's bestfree data.
		 *
		 * Iterate all the fsbcount-aligned block offsets in
		 * this directory.  The directory block reading code is
		 * smart enough to do its own bmap lookups to handle
		 * discontiguous directory blocks.  When we're done
		 * with the extent record, re-query the bmap at the
		 * next fsbcount-aligned offset to avoid redundant
		 * block checks.
		 */
		for (lblk = roundup((xfs_dablk_t)got.br_startoff,
				args.geo->fsbcount);
		     lblk < got.br_startoff + got.br_blockcount;
		     lblk += args.geo->fsbcount) {
			error = xchk_directory_free_bestfree(sc, &args,
					lblk);
			if (error)
				goto out;
		}
		dabno = got.br_startoff + got.br_blockcount;
		lblk = roundup(dabno, args.geo->fsbcount);
		found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &icur, &got);
	}
out:
	return error;
}

/* Scrub a whole directory. */
int
xchk_directory(
	struct xfs_scrub	*sc)
{
	struct xchk_dir_ctx	sdc = {
		.dir_iter.actor = xchk_dir_actor,
		.dir_iter.pos = 0,
		.sc = sc,
	};
	size_t			bufsize;
	loff_t			oldpos;
	int			error = 0;

	if (!S_ISDIR(VFS_I(sc->ip)->i_mode))
		return -ENOENT;

	/* Plausible size? */
	if (sc->ip->i_d.di_size < xfs_dir2_sf_hdr_size(0)) {
		xchk_ino_set_corrupt(sc, sc->ip->i_ino);
		goto out;
	}

	/* Check directory tree structure */
	error = xchk_da_btree(sc, XFS_DATA_FORK, xchk_dir_rec, NULL);
	if (error)
		return error;

	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
		return error;

	/* Check the freespace. */
	error = xchk_directory_blocks(sc);
	if (error)
		return error;

	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
		return error;

	/*
	 * Check that every dirent we see can also be looked up by hash.
	 * Userspace usually asks for a 32k buffer, so we will too.
	 */
	bufsize = (size_t)min_t(loff_t, XFS_READDIR_BUFSIZE,
			sc->ip->i_d.di_size);

	/*
	 * Look up every name in this directory by hash.
	 *
	 * Use the xfs_readdir function to call xchk_dir_actor on
	 * every directory entry in this directory.  In _actor, we check
	 * the name, inode number, and ftype (if applicable) of the
	 * entry.  xfs_readdir uses the VFS filldir functions to provide
	 * iteration context.
	 *
	 * The VFS grabs a read or write lock via i_rwsem before it reads
	 * or writes to a directory.  If we've gotten this far we've
	 * already obtained IOLOCK_EXCL, which (since 4.10) is the same as
	 * getting a write lock on i_rwsem.  Therefore, it is safe for us
	 * to drop the ILOCK here in order to reuse the _readdir and
	 * _dir_lookup routines, which do their own ILOCK locking.
	 */
	oldpos = 0;
	sc->ilock_flags &= ~XFS_ILOCK_EXCL;
	xfs_iunlock(sc->ip, XFS_ILOCK_EXCL);
	while (true) {
		error = xfs_readdir(sc->tp, sc->ip, &sdc.dir_iter, bufsize);
		if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, 0,
				&error))
			goto out;
		if (oldpos == sdc.dir_iter.pos)
			break;
		oldpos = sdc.dir_iter.pos;
	}

out:
	return error;
}