xref: /openbmc/linux/fs/xfs/scrub/bmap.c (revision 9b93eb47)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2017 Oracle.  All Rights Reserved.
4  * Author: Darrick J. Wong <darrick.wong@oracle.com>
5  */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_trans_resv.h"
11 #include "xfs_mount.h"
12 #include "xfs_defer.h"
13 #include "xfs_btree.h"
14 #include "xfs_bit.h"
15 #include "xfs_log_format.h"
16 #include "xfs_trans.h"
17 #include "xfs_sb.h"
18 #include "xfs_inode.h"
19 #include "xfs_inode_fork.h"
20 #include "xfs_alloc.h"
21 #include "xfs_rtalloc.h"
22 #include "xfs_bmap.h"
23 #include "xfs_bmap_util.h"
24 #include "xfs_bmap_btree.h"
25 #include "xfs_rmap.h"
26 #include "xfs_rmap_btree.h"
27 #include "xfs_refcount.h"
28 #include "scrub/xfs_scrub.h"
29 #include "scrub/scrub.h"
30 #include "scrub/common.h"
31 #include "scrub/btree.h"
32 #include "scrub/trace.h"
33 
34 /* Set us up with an inode's bmap. */
35 int
36 xchk_setup_inode_bmap(
37 	struct xfs_scrub	*sc,
38 	struct xfs_inode	*ip)
39 {
40 	int			error;
41 
42 	error = xchk_get_inode(sc, ip);
43 	if (error)
44 		goto out;
45 
46 	sc->ilock_flags = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
47 	xfs_ilock(sc->ip, sc->ilock_flags);
48 
49 	/*
50 	 * We don't want any ephemeral data fork updates sitting around
51 	 * while we inspect block mappings, so wait for directio to finish
52 	 * and flush dirty data if we have delalloc reservations.
53 	 */
54 	if (S_ISREG(VFS_I(sc->ip)->i_mode) &&
55 	    sc->sm->sm_type == XFS_SCRUB_TYPE_BMBTD) {
56 		inode_dio_wait(VFS_I(sc->ip));
57 		error = filemap_write_and_wait(VFS_I(sc->ip)->i_mapping);
58 		if (error)
59 			goto out;
60 	}
61 
62 	/* Got the inode, lock it and we're ready to go. */
63 	error = xchk_trans_alloc(sc, 0);
64 	if (error)
65 		goto out;
66 	sc->ilock_flags |= XFS_ILOCK_EXCL;
67 	xfs_ilock(sc->ip, XFS_ILOCK_EXCL);
68 
69 out:
70 	/* scrub teardown will unlock and release the inode */
71 	return error;
72 }
73 
74 /*
75  * Inode fork block mapping (BMBT) scrubber.
76  * More complex than the others because we have to scrub
77  * all the extents regardless of whether or not the fork
78  * is in btree format.
79  */
80 
81 struct xchk_bmap_info {
82 	struct xfs_scrub	*sc;
83 	xfs_fileoff_t		lastoff;
84 	bool			is_rt;
85 	bool			is_shared;
86 	int			whichfork;
87 };
88 
89 /* Look for a corresponding rmap for this irec. */
90 static inline bool
91 xchk_bmap_get_rmap(
92 	struct xchk_bmap_info	*info,
93 	struct xfs_bmbt_irec	*irec,
94 	xfs_agblock_t		agbno,
95 	uint64_t		owner,
96 	struct xfs_rmap_irec	*rmap)
97 {
98 	xfs_fileoff_t		offset;
99 	unsigned int		rflags = 0;
100 	int			has_rmap;
101 	int			error;
102 
103 	if (info->whichfork == XFS_ATTR_FORK)
104 		rflags |= XFS_RMAP_ATTR_FORK;
105 
106 	/*
107 	 * CoW staging extents are owned (on disk) by the refcountbt, so
108 	 * their rmaps do not have offsets.
109 	 */
110 	if (info->whichfork == XFS_COW_FORK)
111 		offset = 0;
112 	else
113 		offset = irec->br_startoff;
114 
115 	/*
116 	 * If the caller thinks this could be a shared bmbt extent (IOWs,
117 	 * any data fork extent of a reflink inode) then we have to use the
118 	 * range rmap lookup to make sure we get the correct owner/offset.
119 	 */
120 	if (info->is_shared) {
121 		error = xfs_rmap_lookup_le_range(info->sc->sa.rmap_cur, agbno,
122 				owner, offset, rflags, rmap, &has_rmap);
123 		if (!xchk_should_check_xref(info->sc, &error,
124 				&info->sc->sa.rmap_cur))
125 			return false;
126 		goto out;
127 	}
128 
129 	/*
130 	 * Otherwise, use the (faster) regular lookup.
131 	 */
132 	error = xfs_rmap_lookup_le(info->sc->sa.rmap_cur, agbno, 0, owner,
133 			offset, rflags, &has_rmap);
134 	if (!xchk_should_check_xref(info->sc, &error,
135 			&info->sc->sa.rmap_cur))
136 		return false;
137 	if (!has_rmap)
138 		goto out;
139 
140 	error = xfs_rmap_get_rec(info->sc->sa.rmap_cur, rmap, &has_rmap);
141 	if (!xchk_should_check_xref(info->sc, &error,
142 			&info->sc->sa.rmap_cur))
143 		return false;
144 
145 out:
146 	if (!has_rmap)
147 		xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
148 			irec->br_startoff);
149 	return has_rmap;
150 }
151 
152 /* Make sure that we have rmapbt records for this extent. */
153 STATIC void
154 xchk_bmap_xref_rmap(
155 	struct xchk_bmap_info	*info,
156 	struct xfs_bmbt_irec	*irec,
157 	xfs_agblock_t		agbno)
158 {
159 	struct xfs_rmap_irec	rmap;
160 	unsigned long long	rmap_end;
161 	uint64_t		owner;
162 
163 	if (!info->sc->sa.rmap_cur || xchk_skip_xref(info->sc->sm))
164 		return;
165 
166 	if (info->whichfork == XFS_COW_FORK)
167 		owner = XFS_RMAP_OWN_COW;
168 	else
169 		owner = info->sc->ip->i_ino;
170 
171 	/* Find the rmap record for this irec. */
172 	if (!xchk_bmap_get_rmap(info, irec, agbno, owner, &rmap))
173 		return;
174 
175 	/* Check the rmap. */
176 	rmap_end = (unsigned long long)rmap.rm_startblock + rmap.rm_blockcount;
177 	if (rmap.rm_startblock > agbno ||
178 	    agbno + irec->br_blockcount > rmap_end)
179 		xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
180 				irec->br_startoff);
181 
182 	/*
183 	 * Check the logical offsets if applicable.  CoW staging extents
184 	 * don't track logical offsets since the mappings only exist in
185 	 * memory.
186 	 */
187 	if (info->whichfork != XFS_COW_FORK) {
188 		rmap_end = (unsigned long long)rmap.rm_offset +
189 				rmap.rm_blockcount;
190 		if (rmap.rm_offset > irec->br_startoff ||
191 		    irec->br_startoff + irec->br_blockcount > rmap_end)
192 			xchk_fblock_xref_set_corrupt(info->sc,
193 					info->whichfork, irec->br_startoff);
194 	}
195 
196 	if (rmap.rm_owner != owner)
197 		xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
198 				irec->br_startoff);
199 
200 	/*
201 	 * Check for discrepancies between the unwritten flag in the irec and
202 	 * the rmap.  Note that the (in-memory) CoW fork distinguishes between
203 	 * unwritten and written extents, but we don't track that in the rmap
204 	 * records because the blocks are owned (on-disk) by the refcountbt,
205 	 * which doesn't track unwritten state.
206 	 */
207 	if (owner != XFS_RMAP_OWN_COW &&
208 	    irec->br_state == XFS_EXT_UNWRITTEN &&
209 	    !(rmap.rm_flags & XFS_RMAP_UNWRITTEN))
210 		xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
211 				irec->br_startoff);
212 
213 	if (info->whichfork == XFS_ATTR_FORK &&
214 	    !(rmap.rm_flags & XFS_RMAP_ATTR_FORK))
215 		xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
216 				irec->br_startoff);
217 	if (rmap.rm_flags & XFS_RMAP_BMBT_BLOCK)
218 		xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
219 				irec->br_startoff);
220 }
221 
222 /* Cross-reference a single rtdev extent record. */
223 STATIC void
224 xchk_bmap_rt_extent_xref(
225 	struct xchk_bmap_info	*info,
226 	struct xfs_inode	*ip,
227 	struct xfs_btree_cur	*cur,
228 	struct xfs_bmbt_irec	*irec)
229 {
230 	if (info->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
231 		return;
232 
233 	xchk_xref_is_used_rt_space(info->sc, irec->br_startblock,
234 			irec->br_blockcount);
235 }
236 
237 /* Cross-reference a single datadev extent record. */
238 STATIC void
239 xchk_bmap_extent_xref(
240 	struct xchk_bmap_info	*info,
241 	struct xfs_inode	*ip,
242 	struct xfs_btree_cur	*cur,
243 	struct xfs_bmbt_irec	*irec)
244 {
245 	struct xfs_mount	*mp = info->sc->mp;
246 	xfs_agnumber_t		agno;
247 	xfs_agblock_t		agbno;
248 	xfs_extlen_t		len;
249 	int			error;
250 
251 	if (info->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
252 		return;
253 
254 	agno = XFS_FSB_TO_AGNO(mp, irec->br_startblock);
255 	agbno = XFS_FSB_TO_AGBNO(mp, irec->br_startblock);
256 	len = irec->br_blockcount;
257 
258 	error = xchk_ag_init(info->sc, agno, &info->sc->sa);
259 	if (!xchk_fblock_process_error(info->sc, info->whichfork,
260 			irec->br_startoff, &error))
261 		return;
262 
263 	xchk_xref_is_used_space(info->sc, agbno, len);
264 	xchk_xref_is_not_inode_chunk(info->sc, agbno, len);
265 	xchk_bmap_xref_rmap(info, irec, agbno);
266 	switch (info->whichfork) {
267 	case XFS_DATA_FORK:
268 		if (xfs_is_reflink_inode(info->sc->ip))
269 			break;
270 		/* fall through */
271 	case XFS_ATTR_FORK:
272 		xchk_xref_is_not_shared(info->sc, agbno,
273 				irec->br_blockcount);
274 		break;
275 	case XFS_COW_FORK:
276 		xchk_xref_is_cow_staging(info->sc, agbno,
277 				irec->br_blockcount);
278 		break;
279 	}
280 
281 	xchk_ag_free(info->sc, &info->sc->sa);
282 }
283 
284 /*
285  * Directories and attr forks should never have blocks that can't be addressed
286  * by a xfs_dablk_t.
287  */
288 STATIC void
289 xchk_bmap_dirattr_extent(
290 	struct xfs_inode	*ip,
291 	struct xchk_bmap_info	*info,
292 	struct xfs_bmbt_irec	*irec)
293 {
294 	struct xfs_mount	*mp = ip->i_mount;
295 	xfs_fileoff_t		off;
296 
297 	if (!S_ISDIR(VFS_I(ip)->i_mode) && info->whichfork != XFS_ATTR_FORK)
298 		return;
299 
300 	if (!xfs_verify_dablk(mp, irec->br_startoff))
301 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
302 				irec->br_startoff);
303 
304 	off = irec->br_startoff + irec->br_blockcount - 1;
305 	if (!xfs_verify_dablk(mp, off))
306 		xchk_fblock_set_corrupt(info->sc, info->whichfork, off);
307 }
308 
309 /* Scrub a single extent record. */
310 STATIC int
311 xchk_bmap_extent(
312 	struct xfs_inode	*ip,
313 	struct xfs_btree_cur	*cur,
314 	struct xchk_bmap_info	*info,
315 	struct xfs_bmbt_irec	*irec)
316 {
317 	struct xfs_mount	*mp = info->sc->mp;
318 	struct xfs_buf		*bp = NULL;
319 	xfs_filblks_t		end;
320 	int			error = 0;
321 
322 	if (cur)
323 		xfs_btree_get_block(cur, 0, &bp);
324 
325 	/*
326 	 * Check for out-of-order extents.  This record could have come
327 	 * from the incore list, for which there is no ordering check.
328 	 */
329 	if (irec->br_startoff < info->lastoff)
330 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
331 				irec->br_startoff);
332 
333 	xchk_bmap_dirattr_extent(ip, info, irec);
334 
335 	/* There should never be a "hole" extent in either extent list. */
336 	if (irec->br_startblock == HOLESTARTBLOCK)
337 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
338 				irec->br_startoff);
339 
340 	/*
341 	 * Check for delalloc extents.  We never iterate the ones in the
342 	 * in-core extent scan, and we should never see these in the bmbt.
343 	 */
344 	if (isnullstartblock(irec->br_startblock))
345 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
346 				irec->br_startoff);
347 
348 	/* Make sure the extent points to a valid place. */
349 	if (irec->br_blockcount > MAXEXTLEN)
350 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
351 				irec->br_startoff);
352 	if (irec->br_startblock + irec->br_blockcount <= irec->br_startblock)
353 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
354 				irec->br_startoff);
355 	end = irec->br_startblock + irec->br_blockcount - 1;
356 	if (info->is_rt &&
357 	    (!xfs_verify_rtbno(mp, irec->br_startblock) ||
358 	     !xfs_verify_rtbno(mp, end)))
359 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
360 				irec->br_startoff);
361 	if (!info->is_rt &&
362 	    (!xfs_verify_fsbno(mp, irec->br_startblock) ||
363 	     !xfs_verify_fsbno(mp, end) ||
364 	     XFS_FSB_TO_AGNO(mp, irec->br_startblock) !=
365 				XFS_FSB_TO_AGNO(mp, end)))
366 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
367 				irec->br_startoff);
368 
369 	/* We don't allow unwritten extents on attr forks. */
370 	if (irec->br_state == XFS_EXT_UNWRITTEN &&
371 	    info->whichfork == XFS_ATTR_FORK)
372 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
373 				irec->br_startoff);
374 
375 	if (info->is_rt)
376 		xchk_bmap_rt_extent_xref(info, ip, cur, irec);
377 	else
378 		xchk_bmap_extent_xref(info, ip, cur, irec);
379 
380 	info->lastoff = irec->br_startoff + irec->br_blockcount;
381 	return error;
382 }
383 
384 /* Scrub a bmbt record. */
385 STATIC int
386 xchk_bmapbt_rec(
387 	struct xchk_btree	*bs,
388 	union xfs_btree_rec	*rec)
389 {
390 	struct xfs_bmbt_irec	irec;
391 	struct xchk_bmap_info	*info = bs->private;
392 	struct xfs_inode	*ip = bs->cur->bc_private.b.ip;
393 	struct xfs_buf		*bp = NULL;
394 	struct xfs_btree_block	*block;
395 	uint64_t		owner;
396 	int			i;
397 
398 	/*
399 	 * Check the owners of the btree blocks up to the level below
400 	 * the root since the verifiers don't do that.
401 	 */
402 	if (xfs_sb_version_hascrc(&bs->cur->bc_mp->m_sb) &&
403 	    bs->cur->bc_ptrs[0] == 1) {
404 		for (i = 0; i < bs->cur->bc_nlevels - 1; i++) {
405 			block = xfs_btree_get_block(bs->cur, i, &bp);
406 			owner = be64_to_cpu(block->bb_u.l.bb_owner);
407 			if (owner != ip->i_ino)
408 				xchk_fblock_set_corrupt(bs->sc,
409 						info->whichfork, 0);
410 		}
411 	}
412 
413 	/* Set up the in-core record and scrub it. */
414 	xfs_bmbt_disk_get_all(&rec->bmbt, &irec);
415 	return xchk_bmap_extent(ip, bs->cur, info, &irec);
416 }
417 
418 /* Scan the btree records. */
419 STATIC int
420 xchk_bmap_btree(
421 	struct xfs_scrub	*sc,
422 	int			whichfork,
423 	struct xchk_bmap_info	*info)
424 {
425 	struct xfs_owner_info	oinfo;
426 	struct xfs_mount	*mp = sc->mp;
427 	struct xfs_inode	*ip = sc->ip;
428 	struct xfs_btree_cur	*cur;
429 	int			error;
430 
431 	cur = xfs_bmbt_init_cursor(mp, sc->tp, ip, whichfork);
432 	xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, whichfork);
433 	error = xchk_btree(sc, cur, xchk_bmapbt_rec, &oinfo, info);
434 	xfs_btree_del_cursor(cur, error);
435 	return error;
436 }
437 
438 struct xchk_bmap_check_rmap_info {
439 	struct xfs_scrub	*sc;
440 	int			whichfork;
441 	struct xfs_iext_cursor	icur;
442 };
443 
444 /* Can we find bmaps that fit this rmap? */
445 STATIC int
446 xchk_bmap_check_rmap(
447 	struct xfs_btree_cur		*cur,
448 	struct xfs_rmap_irec		*rec,
449 	void				*priv)
450 {
451 	struct xfs_bmbt_irec		irec;
452 	struct xchk_bmap_check_rmap_info	*sbcri = priv;
453 	struct xfs_ifork		*ifp;
454 	struct xfs_scrub		*sc = sbcri->sc;
455 	bool				have_map;
456 
457 	/* Is this even the right fork? */
458 	if (rec->rm_owner != sc->ip->i_ino)
459 		return 0;
460 	if ((sbcri->whichfork == XFS_ATTR_FORK) ^
461 	    !!(rec->rm_flags & XFS_RMAP_ATTR_FORK))
462 		return 0;
463 	if (rec->rm_flags & XFS_RMAP_BMBT_BLOCK)
464 		return 0;
465 
466 	/* Now look up the bmbt record. */
467 	ifp = XFS_IFORK_PTR(sc->ip, sbcri->whichfork);
468 	if (!ifp) {
469 		xchk_fblock_set_corrupt(sc, sbcri->whichfork,
470 				rec->rm_offset);
471 		goto out;
472 	}
473 	have_map = xfs_iext_lookup_extent(sc->ip, ifp, rec->rm_offset,
474 			&sbcri->icur, &irec);
475 	if (!have_map)
476 		xchk_fblock_set_corrupt(sc, sbcri->whichfork,
477 				rec->rm_offset);
478 	/*
479 	 * bmap extent record lengths are constrained to 2^21 blocks in length
480 	 * because of space constraints in the on-disk metadata structure.
481 	 * However, rmap extent record lengths are constrained only by AG
482 	 * length, so we have to loop through the bmbt to make sure that the
483 	 * entire rmap is covered by bmbt records.
484 	 */
485 	while (have_map) {
486 		if (irec.br_startoff != rec->rm_offset)
487 			xchk_fblock_set_corrupt(sc, sbcri->whichfork,
488 					rec->rm_offset);
489 		if (irec.br_startblock != XFS_AGB_TO_FSB(sc->mp,
490 				cur->bc_private.a.agno, rec->rm_startblock))
491 			xchk_fblock_set_corrupt(sc, sbcri->whichfork,
492 					rec->rm_offset);
493 		if (irec.br_blockcount > rec->rm_blockcount)
494 			xchk_fblock_set_corrupt(sc, sbcri->whichfork,
495 					rec->rm_offset);
496 		if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
497 			break;
498 		rec->rm_startblock += irec.br_blockcount;
499 		rec->rm_offset += irec.br_blockcount;
500 		rec->rm_blockcount -= irec.br_blockcount;
501 		if (rec->rm_blockcount == 0)
502 			break;
503 		have_map = xfs_iext_next_extent(ifp, &sbcri->icur, &irec);
504 		if (!have_map)
505 			xchk_fblock_set_corrupt(sc, sbcri->whichfork,
506 					rec->rm_offset);
507 	}
508 
509 out:
510 	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
511 		return XFS_BTREE_QUERY_RANGE_ABORT;
512 	return 0;
513 }
514 
515 /* Make sure each rmap has a corresponding bmbt entry. */
516 STATIC int
517 xchk_bmap_check_ag_rmaps(
518 	struct xfs_scrub		*sc,
519 	int				whichfork,
520 	xfs_agnumber_t			agno)
521 {
522 	struct xchk_bmap_check_rmap_info	sbcri;
523 	struct xfs_btree_cur		*cur;
524 	struct xfs_buf			*agf;
525 	int				error;
526 
527 	error = xfs_alloc_read_agf(sc->mp, sc->tp, agno, 0, &agf);
528 	if (error)
529 		return error;
530 
531 	cur = xfs_rmapbt_init_cursor(sc->mp, sc->tp, agf, agno);
532 	if (!cur) {
533 		error = -ENOMEM;
534 		goto out_agf;
535 	}
536 
537 	sbcri.sc = sc;
538 	sbcri.whichfork = whichfork;
539 	error = xfs_rmap_query_all(cur, xchk_bmap_check_rmap, &sbcri);
540 	if (error == XFS_BTREE_QUERY_RANGE_ABORT)
541 		error = 0;
542 
543 	xfs_btree_del_cursor(cur, error);
544 out_agf:
545 	xfs_trans_brelse(sc->tp, agf);
546 	return error;
547 }
548 
549 /* Make sure each rmap has a corresponding bmbt entry. */
550 STATIC int
551 xchk_bmap_check_rmaps(
552 	struct xfs_scrub	*sc,
553 	int			whichfork)
554 {
555 	loff_t			size;
556 	xfs_agnumber_t		agno;
557 	int			error;
558 
559 	if (!xfs_sb_version_hasrmapbt(&sc->mp->m_sb) ||
560 	    whichfork == XFS_COW_FORK ||
561 	    (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
562 		return 0;
563 
564 	/* Don't support realtime rmap checks yet. */
565 	if (XFS_IS_REALTIME_INODE(sc->ip) && whichfork == XFS_DATA_FORK)
566 		return 0;
567 
568 	/*
569 	 * Only do this for complex maps that are in btree format, or for
570 	 * situations where we would seem to have a size but zero extents.
571 	 * The inode repair code can zap broken iforks, which means we have
572 	 * to flag this bmap as corrupt if there are rmaps that need to be
573 	 * reattached.
574 	 */
575 	switch (whichfork) {
576 	case XFS_DATA_FORK:
577 		size = i_size_read(VFS_I(sc->ip));
578 		break;
579 	case XFS_ATTR_FORK:
580 		size = XFS_IFORK_Q(sc->ip);
581 		break;
582 	default:
583 		size = 0;
584 		break;
585 	}
586 	if (XFS_IFORK_FORMAT(sc->ip, whichfork) != XFS_DINODE_FMT_BTREE &&
587 	    (size == 0 || XFS_IFORK_NEXTENTS(sc->ip, whichfork) > 0))
588 		return 0;
589 
590 	for (agno = 0; agno < sc->mp->m_sb.sb_agcount; agno++) {
591 		error = xchk_bmap_check_ag_rmaps(sc, whichfork, agno);
592 		if (error)
593 			return error;
594 		if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
595 			break;
596 	}
597 
598 	return 0;
599 }
600 
601 /*
602  * Scrub an inode fork's block mappings.
603  *
604  * First we scan every record in every btree block, if applicable.
605  * Then we unconditionally scan the incore extent cache.
606  */
607 STATIC int
608 xchk_bmap(
609 	struct xfs_scrub	*sc,
610 	int			whichfork)
611 {
612 	struct xfs_bmbt_irec	irec;
613 	struct xchk_bmap_info	info = { NULL };
614 	struct xfs_mount	*mp = sc->mp;
615 	struct xfs_inode	*ip = sc->ip;
616 	struct xfs_ifork	*ifp;
617 	xfs_fileoff_t		endoff;
618 	struct xfs_iext_cursor	icur;
619 	int			error = 0;
620 
621 	ifp = XFS_IFORK_PTR(ip, whichfork);
622 
623 	info.is_rt = whichfork == XFS_DATA_FORK && XFS_IS_REALTIME_INODE(ip);
624 	info.whichfork = whichfork;
625 	info.is_shared = whichfork == XFS_DATA_FORK && xfs_is_reflink_inode(ip);
626 	info.sc = sc;
627 
628 	switch (whichfork) {
629 	case XFS_COW_FORK:
630 		/* Non-existent CoW forks are ignorable. */
631 		if (!ifp)
632 			goto out;
633 		/* No CoW forks on non-reflink inodes/filesystems. */
634 		if (!xfs_is_reflink_inode(ip)) {
635 			xchk_ino_set_corrupt(sc, sc->ip->i_ino);
636 			goto out;
637 		}
638 		break;
639 	case XFS_ATTR_FORK:
640 		if (!ifp)
641 			goto out_check_rmap;
642 		if (!xfs_sb_version_hasattr(&mp->m_sb) &&
643 		    !xfs_sb_version_hasattr2(&mp->m_sb))
644 			xchk_ino_set_corrupt(sc, sc->ip->i_ino);
645 		break;
646 	default:
647 		ASSERT(whichfork == XFS_DATA_FORK);
648 		break;
649 	}
650 
651 	/* Check the fork values */
652 	switch (XFS_IFORK_FORMAT(ip, whichfork)) {
653 	case XFS_DINODE_FMT_UUID:
654 	case XFS_DINODE_FMT_DEV:
655 	case XFS_DINODE_FMT_LOCAL:
656 		/* No mappings to check. */
657 		goto out;
658 	case XFS_DINODE_FMT_EXTENTS:
659 		if (!(ifp->if_flags & XFS_IFEXTENTS)) {
660 			xchk_fblock_set_corrupt(sc, whichfork, 0);
661 			goto out;
662 		}
663 		break;
664 	case XFS_DINODE_FMT_BTREE:
665 		if (whichfork == XFS_COW_FORK) {
666 			xchk_fblock_set_corrupt(sc, whichfork, 0);
667 			goto out;
668 		}
669 
670 		error = xchk_bmap_btree(sc, whichfork, &info);
671 		if (error)
672 			goto out;
673 		break;
674 	default:
675 		xchk_fblock_set_corrupt(sc, whichfork, 0);
676 		goto out;
677 	}
678 
679 	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
680 		goto out;
681 
682 	/* Now try to scrub the in-memory extent list. */
683         if (!(ifp->if_flags & XFS_IFEXTENTS)) {
684 		error = xfs_iread_extents(sc->tp, ip, whichfork);
685 		if (!xchk_fblock_process_error(sc, whichfork, 0, &error))
686 			goto out;
687 	}
688 
689 	/* Find the offset of the last extent in the mapping. */
690 	error = xfs_bmap_last_offset(ip, &endoff, whichfork);
691 	if (!xchk_fblock_process_error(sc, whichfork, 0, &error))
692 		goto out;
693 
694 	/* Scrub extent records. */
695 	info.lastoff = 0;
696 	ifp = XFS_IFORK_PTR(ip, whichfork);
697 	for_each_xfs_iext(ifp, &icur, &irec) {
698 		if (xchk_should_terminate(sc, &error) ||
699 		    (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
700 			break;
701 		if (isnullstartblock(irec.br_startblock))
702 			continue;
703 		if (irec.br_startoff >= endoff) {
704 			xchk_fblock_set_corrupt(sc, whichfork,
705 					irec.br_startoff);
706 			goto out;
707 		}
708 		error = xchk_bmap_extent(ip, NULL, &info, &irec);
709 		if (error)
710 			goto out;
711 	}
712 
713 out_check_rmap:
714 	error = xchk_bmap_check_rmaps(sc, whichfork);
715 	if (!xchk_fblock_xref_process_error(sc, whichfork, 0, &error))
716 		goto out;
717 out:
718 	return error;
719 }
720 
721 /* Scrub an inode's data fork. */
722 int
723 xchk_bmap_data(
724 	struct xfs_scrub	*sc)
725 {
726 	return xchk_bmap(sc, XFS_DATA_FORK);
727 }
728 
729 /* Scrub an inode's attr fork. */
730 int
731 xchk_bmap_attr(
732 	struct xfs_scrub	*sc)
733 {
734 	return xchk_bmap(sc, XFS_ATTR_FORK);
735 }
736 
737 /* Scrub an inode's CoW fork. */
738 int
739 xchk_bmap_cow(
740 	struct xfs_scrub	*sc)
741 {
742 	if (!xfs_is_reflink_inode(sc->ip))
743 		return -ENOENT;
744 
745 	return xchk_bmap(sc, XFS_COW_FORK);
746 }
747