xref: /openbmc/linux/fs/xfs/scrub/agheader_repair.c (revision ed84ef1c)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2018 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_btree.h"
13 #include "xfs_log_format.h"
14 #include "xfs_trans.h"
15 #include "xfs_sb.h"
16 #include "xfs_alloc.h"
17 #include "xfs_alloc_btree.h"
18 #include "xfs_ialloc.h"
19 #include "xfs_ialloc_btree.h"
20 #include "xfs_rmap.h"
21 #include "xfs_rmap_btree.h"
22 #include "xfs_refcount_btree.h"
23 #include "xfs_ag.h"
24 #include "scrub/scrub.h"
25 #include "scrub/common.h"
26 #include "scrub/trace.h"
27 #include "scrub/repair.h"
28 #include "scrub/bitmap.h"
29 
30 /* Superblock */
31 
32 /* Repair the superblock. */
33 int
34 xrep_superblock(
35 	struct xfs_scrub	*sc)
36 {
37 	struct xfs_mount	*mp = sc->mp;
38 	struct xfs_buf		*bp;
39 	xfs_agnumber_t		agno;
40 	int			error;
41 
42 	/* Don't try to repair AG 0's sb; let xfs_repair deal with it. */
43 	agno = sc->sm->sm_agno;
44 	if (agno == 0)
45 		return -EOPNOTSUPP;
46 
47 	error = xfs_sb_get_secondary(mp, sc->tp, agno, &bp);
48 	if (error)
49 		return error;
50 
51 	/* Copy AG 0's superblock to this one. */
52 	xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
53 	xfs_sb_to_disk(bp->b_addr, &mp->m_sb);
54 
55 	/* Write this to disk. */
56 	xfs_trans_buf_set_type(sc->tp, bp, XFS_BLFT_SB_BUF);
57 	xfs_trans_log_buf(sc->tp, bp, 0, BBTOB(bp->b_length) - 1);
58 	return error;
59 }
60 
61 /* AGF */
62 
63 struct xrep_agf_allocbt {
64 	struct xfs_scrub	*sc;
65 	xfs_agblock_t		freeblks;
66 	xfs_agblock_t		longest;
67 };
68 
69 /* Record free space shape information. */
70 STATIC int
71 xrep_agf_walk_allocbt(
72 	struct xfs_btree_cur		*cur,
73 	const struct xfs_alloc_rec_incore *rec,
74 	void				*priv)
75 {
76 	struct xrep_agf_allocbt		*raa = priv;
77 	int				error = 0;
78 
79 	if (xchk_should_terminate(raa->sc, &error))
80 		return error;
81 
82 	raa->freeblks += rec->ar_blockcount;
83 	if (rec->ar_blockcount > raa->longest)
84 		raa->longest = rec->ar_blockcount;
85 	return error;
86 }
87 
88 /* Does this AGFL block look sane? */
89 STATIC int
90 xrep_agf_check_agfl_block(
91 	struct xfs_mount	*mp,
92 	xfs_agblock_t		agbno,
93 	void			*priv)
94 {
95 	struct xfs_scrub	*sc = priv;
96 
97 	if (!xfs_verify_agbno(mp, sc->sa.pag->pag_agno, agbno))
98 		return -EFSCORRUPTED;
99 	return 0;
100 }
101 
102 /*
103  * Offset within the xrep_find_ag_btree array for each btree type.  Avoid the
104  * XFS_BTNUM_ names here to avoid creating a sparse array.
105  */
106 enum {
107 	XREP_AGF_BNOBT = 0,
108 	XREP_AGF_CNTBT,
109 	XREP_AGF_RMAPBT,
110 	XREP_AGF_REFCOUNTBT,
111 	XREP_AGF_END,
112 	XREP_AGF_MAX
113 };
114 
115 /* Check a btree root candidate. */
116 static inline bool
117 xrep_check_btree_root(
118 	struct xfs_scrub		*sc,
119 	struct xrep_find_ag_btree	*fab)
120 {
121 	struct xfs_mount		*mp = sc->mp;
122 	xfs_agnumber_t			agno = sc->sm->sm_agno;
123 
124 	return xfs_verify_agbno(mp, agno, fab->root) &&
125 	       fab->height <= XFS_BTREE_MAXLEVELS;
126 }
127 
128 /*
129  * Given the btree roots described by *fab, find the roots, check them for
130  * sanity, and pass the root data back out via *fab.
131  *
132  * This is /also/ a chicken and egg problem because we have to use the rmapbt
133  * (rooted in the AGF) to find the btrees rooted in the AGF.  We also have no
134  * idea if the btrees make any sense.  If we hit obvious corruptions in those
135  * btrees we'll bail out.
136  */
137 STATIC int
138 xrep_agf_find_btrees(
139 	struct xfs_scrub		*sc,
140 	struct xfs_buf			*agf_bp,
141 	struct xrep_find_ag_btree	*fab,
142 	struct xfs_buf			*agfl_bp)
143 {
144 	struct xfs_agf			*old_agf = agf_bp->b_addr;
145 	int				error;
146 
147 	/* Go find the root data. */
148 	error = xrep_find_ag_btree_roots(sc, agf_bp, fab, agfl_bp);
149 	if (error)
150 		return error;
151 
152 	/* We must find the bnobt, cntbt, and rmapbt roots. */
153 	if (!xrep_check_btree_root(sc, &fab[XREP_AGF_BNOBT]) ||
154 	    !xrep_check_btree_root(sc, &fab[XREP_AGF_CNTBT]) ||
155 	    !xrep_check_btree_root(sc, &fab[XREP_AGF_RMAPBT]))
156 		return -EFSCORRUPTED;
157 
158 	/*
159 	 * We relied on the rmapbt to reconstruct the AGF.  If we get a
160 	 * different root then something's seriously wrong.
161 	 */
162 	if (fab[XREP_AGF_RMAPBT].root !=
163 	    be32_to_cpu(old_agf->agf_roots[XFS_BTNUM_RMAPi]))
164 		return -EFSCORRUPTED;
165 
166 	/* We must find the refcountbt root if that feature is enabled. */
167 	if (xfs_has_reflink(sc->mp) &&
168 	    !xrep_check_btree_root(sc, &fab[XREP_AGF_REFCOUNTBT]))
169 		return -EFSCORRUPTED;
170 
171 	return 0;
172 }
173 
174 /*
175  * Reinitialize the AGF header, making an in-core copy of the old contents so
176  * that we know which in-core state needs to be reinitialized.
177  */
178 STATIC void
179 xrep_agf_init_header(
180 	struct xfs_scrub	*sc,
181 	struct xfs_buf		*agf_bp,
182 	struct xfs_agf		*old_agf)
183 {
184 	struct xfs_mount	*mp = sc->mp;
185 	struct xfs_agf		*agf = agf_bp->b_addr;
186 
187 	memcpy(old_agf, agf, sizeof(*old_agf));
188 	memset(agf, 0, BBTOB(agf_bp->b_length));
189 	agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
190 	agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
191 	agf->agf_seqno = cpu_to_be32(sc->sa.pag->pag_agno);
192 	agf->agf_length = cpu_to_be32(xfs_ag_block_count(mp,
193 							sc->sa.pag->pag_agno));
194 	agf->agf_flfirst = old_agf->agf_flfirst;
195 	agf->agf_fllast = old_agf->agf_fllast;
196 	agf->agf_flcount = old_agf->agf_flcount;
197 	if (xfs_has_crc(mp))
198 		uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid);
199 
200 	/* Mark the incore AGF data stale until we're done fixing things. */
201 	ASSERT(sc->sa.pag->pagf_init);
202 	sc->sa.pag->pagf_init = 0;
203 }
204 
205 /* Set btree root information in an AGF. */
206 STATIC void
207 xrep_agf_set_roots(
208 	struct xfs_scrub		*sc,
209 	struct xfs_agf			*agf,
210 	struct xrep_find_ag_btree	*fab)
211 {
212 	agf->agf_roots[XFS_BTNUM_BNOi] =
213 			cpu_to_be32(fab[XREP_AGF_BNOBT].root);
214 	agf->agf_levels[XFS_BTNUM_BNOi] =
215 			cpu_to_be32(fab[XREP_AGF_BNOBT].height);
216 
217 	agf->agf_roots[XFS_BTNUM_CNTi] =
218 			cpu_to_be32(fab[XREP_AGF_CNTBT].root);
219 	agf->agf_levels[XFS_BTNUM_CNTi] =
220 			cpu_to_be32(fab[XREP_AGF_CNTBT].height);
221 
222 	agf->agf_roots[XFS_BTNUM_RMAPi] =
223 			cpu_to_be32(fab[XREP_AGF_RMAPBT].root);
224 	agf->agf_levels[XFS_BTNUM_RMAPi] =
225 			cpu_to_be32(fab[XREP_AGF_RMAPBT].height);
226 
227 	if (xfs_has_reflink(sc->mp)) {
228 		agf->agf_refcount_root =
229 				cpu_to_be32(fab[XREP_AGF_REFCOUNTBT].root);
230 		agf->agf_refcount_level =
231 				cpu_to_be32(fab[XREP_AGF_REFCOUNTBT].height);
232 	}
233 }
234 
235 /* Update all AGF fields which derive from btree contents. */
236 STATIC int
237 xrep_agf_calc_from_btrees(
238 	struct xfs_scrub	*sc,
239 	struct xfs_buf		*agf_bp)
240 {
241 	struct xrep_agf_allocbt	raa = { .sc = sc };
242 	struct xfs_btree_cur	*cur = NULL;
243 	struct xfs_agf		*agf = agf_bp->b_addr;
244 	struct xfs_mount	*mp = sc->mp;
245 	xfs_agblock_t		btreeblks;
246 	xfs_agblock_t		blocks;
247 	int			error;
248 
249 	/* Update the AGF counters from the bnobt. */
250 	cur = xfs_allocbt_init_cursor(mp, sc->tp, agf_bp,
251 			sc->sa.pag, XFS_BTNUM_BNO);
252 	error = xfs_alloc_query_all(cur, xrep_agf_walk_allocbt, &raa);
253 	if (error)
254 		goto err;
255 	error = xfs_btree_count_blocks(cur, &blocks);
256 	if (error)
257 		goto err;
258 	xfs_btree_del_cursor(cur, error);
259 	btreeblks = blocks - 1;
260 	agf->agf_freeblks = cpu_to_be32(raa.freeblks);
261 	agf->agf_longest = cpu_to_be32(raa.longest);
262 
263 	/* Update the AGF counters from the cntbt. */
264 	cur = xfs_allocbt_init_cursor(mp, sc->tp, agf_bp,
265 			sc->sa.pag, XFS_BTNUM_CNT);
266 	error = xfs_btree_count_blocks(cur, &blocks);
267 	if (error)
268 		goto err;
269 	xfs_btree_del_cursor(cur, error);
270 	btreeblks += blocks - 1;
271 
272 	/* Update the AGF counters from the rmapbt. */
273 	cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.pag);
274 	error = xfs_btree_count_blocks(cur, &blocks);
275 	if (error)
276 		goto err;
277 	xfs_btree_del_cursor(cur, error);
278 	agf->agf_rmap_blocks = cpu_to_be32(blocks);
279 	btreeblks += blocks - 1;
280 
281 	agf->agf_btreeblks = cpu_to_be32(btreeblks);
282 
283 	/* Update the AGF counters from the refcountbt. */
284 	if (xfs_has_reflink(mp)) {
285 		cur = xfs_refcountbt_init_cursor(mp, sc->tp, agf_bp,
286 				sc->sa.pag);
287 		error = xfs_btree_count_blocks(cur, &blocks);
288 		if (error)
289 			goto err;
290 		xfs_btree_del_cursor(cur, error);
291 		agf->agf_refcount_blocks = cpu_to_be32(blocks);
292 	}
293 
294 	return 0;
295 err:
296 	xfs_btree_del_cursor(cur, error);
297 	return error;
298 }
299 
300 /* Commit the new AGF and reinitialize the incore state. */
301 STATIC int
302 xrep_agf_commit_new(
303 	struct xfs_scrub	*sc,
304 	struct xfs_buf		*agf_bp)
305 {
306 	struct xfs_perag	*pag;
307 	struct xfs_agf		*agf = agf_bp->b_addr;
308 
309 	/* Trigger fdblocks recalculation */
310 	xfs_force_summary_recalc(sc->mp);
311 
312 	/* Write this to disk. */
313 	xfs_trans_buf_set_type(sc->tp, agf_bp, XFS_BLFT_AGF_BUF);
314 	xfs_trans_log_buf(sc->tp, agf_bp, 0, BBTOB(agf_bp->b_length) - 1);
315 
316 	/* Now reinitialize the in-core counters we changed. */
317 	pag = sc->sa.pag;
318 	pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
319 	pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
320 	pag->pagf_longest = be32_to_cpu(agf->agf_longest);
321 	pag->pagf_levels[XFS_BTNUM_BNOi] =
322 			be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]);
323 	pag->pagf_levels[XFS_BTNUM_CNTi] =
324 			be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]);
325 	pag->pagf_levels[XFS_BTNUM_RMAPi] =
326 			be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAPi]);
327 	pag->pagf_refcount_level = be32_to_cpu(agf->agf_refcount_level);
328 	pag->pagf_init = 1;
329 
330 	return 0;
331 }
332 
333 /* Repair the AGF. v5 filesystems only. */
334 int
335 xrep_agf(
336 	struct xfs_scrub		*sc)
337 {
338 	struct xrep_find_ag_btree	fab[XREP_AGF_MAX] = {
339 		[XREP_AGF_BNOBT] = {
340 			.rmap_owner = XFS_RMAP_OWN_AG,
341 			.buf_ops = &xfs_bnobt_buf_ops,
342 		},
343 		[XREP_AGF_CNTBT] = {
344 			.rmap_owner = XFS_RMAP_OWN_AG,
345 			.buf_ops = &xfs_cntbt_buf_ops,
346 		},
347 		[XREP_AGF_RMAPBT] = {
348 			.rmap_owner = XFS_RMAP_OWN_AG,
349 			.buf_ops = &xfs_rmapbt_buf_ops,
350 		},
351 		[XREP_AGF_REFCOUNTBT] = {
352 			.rmap_owner = XFS_RMAP_OWN_REFC,
353 			.buf_ops = &xfs_refcountbt_buf_ops,
354 		},
355 		[XREP_AGF_END] = {
356 			.buf_ops = NULL,
357 		},
358 	};
359 	struct xfs_agf			old_agf;
360 	struct xfs_mount		*mp = sc->mp;
361 	struct xfs_buf			*agf_bp;
362 	struct xfs_buf			*agfl_bp;
363 	struct xfs_agf			*agf;
364 	int				error;
365 
366 	/* We require the rmapbt to rebuild anything. */
367 	if (!xfs_has_rmapbt(mp))
368 		return -EOPNOTSUPP;
369 
370 	/*
371 	 * Make sure we have the AGF buffer, as scrub might have decided it
372 	 * was corrupt after xfs_alloc_read_agf failed with -EFSCORRUPTED.
373 	 */
374 	error = xfs_trans_read_buf(mp, sc->tp, mp->m_ddev_targp,
375 			XFS_AG_DADDR(mp, sc->sa.pag->pag_agno,
376 						XFS_AGF_DADDR(mp)),
377 			XFS_FSS_TO_BB(mp, 1), 0, &agf_bp, NULL);
378 	if (error)
379 		return error;
380 	agf_bp->b_ops = &xfs_agf_buf_ops;
381 	agf = agf_bp->b_addr;
382 
383 	/*
384 	 * Load the AGFL so that we can screen out OWN_AG blocks that are on
385 	 * the AGFL now; these blocks might have once been part of the
386 	 * bno/cnt/rmap btrees but are not now.  This is a chicken and egg
387 	 * problem: the AGF is corrupt, so we have to trust the AGFL contents
388 	 * because we can't do any serious cross-referencing with any of the
389 	 * btrees rooted in the AGF.  If the AGFL contents are obviously bad
390 	 * then we'll bail out.
391 	 */
392 	error = xfs_alloc_read_agfl(mp, sc->tp, sc->sa.pag->pag_agno, &agfl_bp);
393 	if (error)
394 		return error;
395 
396 	/*
397 	 * Spot-check the AGFL blocks; if they're obviously corrupt then
398 	 * there's nothing we can do but bail out.
399 	 */
400 	error = xfs_agfl_walk(sc->mp, agf_bp->b_addr, agfl_bp,
401 			xrep_agf_check_agfl_block, sc);
402 	if (error)
403 		return error;
404 
405 	/*
406 	 * Find the AGF btree roots.  This is also a chicken-and-egg situation;
407 	 * see the function for more details.
408 	 */
409 	error = xrep_agf_find_btrees(sc, agf_bp, fab, agfl_bp);
410 	if (error)
411 		return error;
412 
413 	/* Start rewriting the header and implant the btrees we found. */
414 	xrep_agf_init_header(sc, agf_bp, &old_agf);
415 	xrep_agf_set_roots(sc, agf, fab);
416 	error = xrep_agf_calc_from_btrees(sc, agf_bp);
417 	if (error)
418 		goto out_revert;
419 
420 	/* Commit the changes and reinitialize incore state. */
421 	return xrep_agf_commit_new(sc, agf_bp);
422 
423 out_revert:
424 	/* Mark the incore AGF state stale and revert the AGF. */
425 	sc->sa.pag->pagf_init = 0;
426 	memcpy(agf, &old_agf, sizeof(old_agf));
427 	return error;
428 }
429 
430 /* AGFL */
431 
432 struct xrep_agfl {
433 	/* Bitmap of other OWN_AG metadata blocks. */
434 	struct xbitmap		agmetablocks;
435 
436 	/* Bitmap of free space. */
437 	struct xbitmap		*freesp;
438 
439 	struct xfs_scrub	*sc;
440 };
441 
442 /* Record all OWN_AG (free space btree) information from the rmap data. */
443 STATIC int
444 xrep_agfl_walk_rmap(
445 	struct xfs_btree_cur	*cur,
446 	const struct xfs_rmap_irec *rec,
447 	void			*priv)
448 {
449 	struct xrep_agfl	*ra = priv;
450 	xfs_fsblock_t		fsb;
451 	int			error = 0;
452 
453 	if (xchk_should_terminate(ra->sc, &error))
454 		return error;
455 
456 	/* Record all the OWN_AG blocks. */
457 	if (rec->rm_owner == XFS_RMAP_OWN_AG) {
458 		fsb = XFS_AGB_TO_FSB(cur->bc_mp, cur->bc_ag.pag->pag_agno,
459 				rec->rm_startblock);
460 		error = xbitmap_set(ra->freesp, fsb, rec->rm_blockcount);
461 		if (error)
462 			return error;
463 	}
464 
465 	return xbitmap_set_btcur_path(&ra->agmetablocks, cur);
466 }
467 
468 /*
469  * Map out all the non-AGFL OWN_AG space in this AG so that we can deduce
470  * which blocks belong to the AGFL.
471  *
472  * Compute the set of old AGFL blocks by subtracting from the list of OWN_AG
473  * blocks the list of blocks owned by all other OWN_AG metadata (bnobt, cntbt,
474  * rmapbt).  These are the old AGFL blocks, so return that list and the number
475  * of blocks we're actually going to put back on the AGFL.
476  */
477 STATIC int
478 xrep_agfl_collect_blocks(
479 	struct xfs_scrub	*sc,
480 	struct xfs_buf		*agf_bp,
481 	struct xbitmap		*agfl_extents,
482 	xfs_agblock_t		*flcount)
483 {
484 	struct xrep_agfl	ra;
485 	struct xfs_mount	*mp = sc->mp;
486 	struct xfs_btree_cur	*cur;
487 	int			error;
488 
489 	ra.sc = sc;
490 	ra.freesp = agfl_extents;
491 	xbitmap_init(&ra.agmetablocks);
492 
493 	/* Find all space used by the free space btrees & rmapbt. */
494 	cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.pag);
495 	error = xfs_rmap_query_all(cur, xrep_agfl_walk_rmap, &ra);
496 	if (error)
497 		goto err;
498 	xfs_btree_del_cursor(cur, error);
499 
500 	/* Find all blocks currently being used by the bnobt. */
501 	cur = xfs_allocbt_init_cursor(mp, sc->tp, agf_bp,
502 			sc->sa.pag, XFS_BTNUM_BNO);
503 	error = xbitmap_set_btblocks(&ra.agmetablocks, cur);
504 	if (error)
505 		goto err;
506 	xfs_btree_del_cursor(cur, error);
507 
508 	/* Find all blocks currently being used by the cntbt. */
509 	cur = xfs_allocbt_init_cursor(mp, sc->tp, agf_bp,
510 			sc->sa.pag, XFS_BTNUM_CNT);
511 	error = xbitmap_set_btblocks(&ra.agmetablocks, cur);
512 	if (error)
513 		goto err;
514 
515 	xfs_btree_del_cursor(cur, error);
516 
517 	/*
518 	 * Drop the freesp meta blocks that are in use by btrees.
519 	 * The remaining blocks /should/ be AGFL blocks.
520 	 */
521 	error = xbitmap_disunion(agfl_extents, &ra.agmetablocks);
522 	xbitmap_destroy(&ra.agmetablocks);
523 	if (error)
524 		return error;
525 
526 	/*
527 	 * Calculate the new AGFL size.  If we found more blocks than fit in
528 	 * the AGFL we'll free them later.
529 	 */
530 	*flcount = min_t(uint64_t, xbitmap_hweight(agfl_extents),
531 			 xfs_agfl_size(mp));
532 	return 0;
533 
534 err:
535 	xbitmap_destroy(&ra.agmetablocks);
536 	xfs_btree_del_cursor(cur, error);
537 	return error;
538 }
539 
540 /* Update the AGF and reset the in-core state. */
541 STATIC void
542 xrep_agfl_update_agf(
543 	struct xfs_scrub	*sc,
544 	struct xfs_buf		*agf_bp,
545 	xfs_agblock_t		flcount)
546 {
547 	struct xfs_agf		*agf = agf_bp->b_addr;
548 
549 	ASSERT(flcount <= xfs_agfl_size(sc->mp));
550 
551 	/* Trigger fdblocks recalculation */
552 	xfs_force_summary_recalc(sc->mp);
553 
554 	/* Update the AGF counters. */
555 	if (sc->sa.pag->pagf_init)
556 		sc->sa.pag->pagf_flcount = flcount;
557 	agf->agf_flfirst = cpu_to_be32(0);
558 	agf->agf_flcount = cpu_to_be32(flcount);
559 	agf->agf_fllast = cpu_to_be32(flcount - 1);
560 
561 	xfs_alloc_log_agf(sc->tp, agf_bp,
562 			XFS_AGF_FLFIRST | XFS_AGF_FLLAST | XFS_AGF_FLCOUNT);
563 }
564 
565 /* Write out a totally new AGFL. */
566 STATIC void
567 xrep_agfl_init_header(
568 	struct xfs_scrub	*sc,
569 	struct xfs_buf		*agfl_bp,
570 	struct xbitmap		*agfl_extents,
571 	xfs_agblock_t		flcount)
572 {
573 	struct xfs_mount	*mp = sc->mp;
574 	__be32			*agfl_bno;
575 	struct xbitmap_range	*br;
576 	struct xbitmap_range	*n;
577 	struct xfs_agfl		*agfl;
578 	xfs_agblock_t		agbno;
579 	unsigned int		fl_off;
580 
581 	ASSERT(flcount <= xfs_agfl_size(mp));
582 
583 	/*
584 	 * Start rewriting the header by setting the bno[] array to
585 	 * NULLAGBLOCK, then setting AGFL header fields.
586 	 */
587 	agfl = XFS_BUF_TO_AGFL(agfl_bp);
588 	memset(agfl, 0xFF, BBTOB(agfl_bp->b_length));
589 	agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
590 	agfl->agfl_seqno = cpu_to_be32(sc->sa.pag->pag_agno);
591 	uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
592 
593 	/*
594 	 * Fill the AGFL with the remaining blocks.  If agfl_extents has more
595 	 * blocks than fit in the AGFL, they will be freed in a subsequent
596 	 * step.
597 	 */
598 	fl_off = 0;
599 	agfl_bno = xfs_buf_to_agfl_bno(agfl_bp);
600 	for_each_xbitmap_extent(br, n, agfl_extents) {
601 		agbno = XFS_FSB_TO_AGBNO(mp, br->start);
602 
603 		trace_xrep_agfl_insert(mp, sc->sa.pag->pag_agno, agbno,
604 				br->len);
605 
606 		while (br->len > 0 && fl_off < flcount) {
607 			agfl_bno[fl_off] = cpu_to_be32(agbno);
608 			fl_off++;
609 			agbno++;
610 
611 			/*
612 			 * We've now used br->start by putting it in the AGFL,
613 			 * so bump br so that we don't reap the block later.
614 			 */
615 			br->start++;
616 			br->len--;
617 		}
618 
619 		if (br->len)
620 			break;
621 		list_del(&br->list);
622 		kmem_free(br);
623 	}
624 
625 	/* Write new AGFL to disk. */
626 	xfs_trans_buf_set_type(sc->tp, agfl_bp, XFS_BLFT_AGFL_BUF);
627 	xfs_trans_log_buf(sc->tp, agfl_bp, 0, BBTOB(agfl_bp->b_length) - 1);
628 }
629 
630 /* Repair the AGFL. */
631 int
632 xrep_agfl(
633 	struct xfs_scrub	*sc)
634 {
635 	struct xbitmap		agfl_extents;
636 	struct xfs_mount	*mp = sc->mp;
637 	struct xfs_buf		*agf_bp;
638 	struct xfs_buf		*agfl_bp;
639 	xfs_agblock_t		flcount;
640 	int			error;
641 
642 	/* We require the rmapbt to rebuild anything. */
643 	if (!xfs_has_rmapbt(mp))
644 		return -EOPNOTSUPP;
645 
646 	xbitmap_init(&agfl_extents);
647 
648 	/*
649 	 * Read the AGF so that we can query the rmapbt.  We hope that there's
650 	 * nothing wrong with the AGF, but all the AG header repair functions
651 	 * have this chicken-and-egg problem.
652 	 */
653 	error = xfs_alloc_read_agf(mp, sc->tp, sc->sa.pag->pag_agno, 0,
654 			&agf_bp);
655 	if (error)
656 		return error;
657 
658 	/*
659 	 * Make sure we have the AGFL buffer, as scrub might have decided it
660 	 * was corrupt after xfs_alloc_read_agfl failed with -EFSCORRUPTED.
661 	 */
662 	error = xfs_trans_read_buf(mp, sc->tp, mp->m_ddev_targp,
663 			XFS_AG_DADDR(mp, sc->sa.pag->pag_agno,
664 						XFS_AGFL_DADDR(mp)),
665 			XFS_FSS_TO_BB(mp, 1), 0, &agfl_bp, NULL);
666 	if (error)
667 		return error;
668 	agfl_bp->b_ops = &xfs_agfl_buf_ops;
669 
670 	/* Gather all the extents we're going to put on the new AGFL. */
671 	error = xrep_agfl_collect_blocks(sc, agf_bp, &agfl_extents, &flcount);
672 	if (error)
673 		goto err;
674 
675 	/*
676 	 * Update AGF and AGFL.  We reset the global free block counter when
677 	 * we adjust the AGF flcount (which can fail) so avoid updating any
678 	 * buffers until we know that part works.
679 	 */
680 	xrep_agfl_update_agf(sc, agf_bp, flcount);
681 	xrep_agfl_init_header(sc, agfl_bp, &agfl_extents, flcount);
682 
683 	/*
684 	 * Ok, the AGFL should be ready to go now.  Roll the transaction to
685 	 * make the new AGFL permanent before we start using it to return
686 	 * freespace overflow to the freespace btrees.
687 	 */
688 	sc->sa.agf_bp = agf_bp;
689 	sc->sa.agfl_bp = agfl_bp;
690 	error = xrep_roll_ag_trans(sc);
691 	if (error)
692 		goto err;
693 
694 	/* Dump any AGFL overflow. */
695 	error = xrep_reap_extents(sc, &agfl_extents, &XFS_RMAP_OINFO_AG,
696 			XFS_AG_RESV_AGFL);
697 err:
698 	xbitmap_destroy(&agfl_extents);
699 	return error;
700 }
701 
702 /* AGI */
703 
704 /*
705  * Offset within the xrep_find_ag_btree array for each btree type.  Avoid the
706  * XFS_BTNUM_ names here to avoid creating a sparse array.
707  */
708 enum {
709 	XREP_AGI_INOBT = 0,
710 	XREP_AGI_FINOBT,
711 	XREP_AGI_END,
712 	XREP_AGI_MAX
713 };
714 
715 /*
716  * Given the inode btree roots described by *fab, find the roots, check them
717  * for sanity, and pass the root data back out via *fab.
718  */
719 STATIC int
720 xrep_agi_find_btrees(
721 	struct xfs_scrub		*sc,
722 	struct xrep_find_ag_btree	*fab)
723 {
724 	struct xfs_buf			*agf_bp;
725 	struct xfs_mount		*mp = sc->mp;
726 	int				error;
727 
728 	/* Read the AGF. */
729 	error = xfs_alloc_read_agf(mp, sc->tp, sc->sa.pag->pag_agno, 0,
730 			&agf_bp);
731 	if (error)
732 		return error;
733 
734 	/* Find the btree roots. */
735 	error = xrep_find_ag_btree_roots(sc, agf_bp, fab, NULL);
736 	if (error)
737 		return error;
738 
739 	/* We must find the inobt root. */
740 	if (!xrep_check_btree_root(sc, &fab[XREP_AGI_INOBT]))
741 		return -EFSCORRUPTED;
742 
743 	/* We must find the finobt root if that feature is enabled. */
744 	if (xfs_has_finobt(mp) &&
745 	    !xrep_check_btree_root(sc, &fab[XREP_AGI_FINOBT]))
746 		return -EFSCORRUPTED;
747 
748 	return 0;
749 }
750 
751 /*
752  * Reinitialize the AGI header, making an in-core copy of the old contents so
753  * that we know which in-core state needs to be reinitialized.
754  */
755 STATIC void
756 xrep_agi_init_header(
757 	struct xfs_scrub	*sc,
758 	struct xfs_buf		*agi_bp,
759 	struct xfs_agi		*old_agi)
760 {
761 	struct xfs_agi		*agi = agi_bp->b_addr;
762 	struct xfs_mount	*mp = sc->mp;
763 
764 	memcpy(old_agi, agi, sizeof(*old_agi));
765 	memset(agi, 0, BBTOB(agi_bp->b_length));
766 	agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
767 	agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
768 	agi->agi_seqno = cpu_to_be32(sc->sa.pag->pag_agno);
769 	agi->agi_length = cpu_to_be32(xfs_ag_block_count(mp,
770 							sc->sa.pag->pag_agno));
771 	agi->agi_newino = cpu_to_be32(NULLAGINO);
772 	agi->agi_dirino = cpu_to_be32(NULLAGINO);
773 	if (xfs_has_crc(mp))
774 		uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid);
775 
776 	/* We don't know how to fix the unlinked list yet. */
777 	memcpy(&agi->agi_unlinked, &old_agi->agi_unlinked,
778 			sizeof(agi->agi_unlinked));
779 
780 	/* Mark the incore AGF data stale until we're done fixing things. */
781 	ASSERT(sc->sa.pag->pagi_init);
782 	sc->sa.pag->pagi_init = 0;
783 }
784 
785 /* Set btree root information in an AGI. */
786 STATIC void
787 xrep_agi_set_roots(
788 	struct xfs_scrub		*sc,
789 	struct xfs_agi			*agi,
790 	struct xrep_find_ag_btree	*fab)
791 {
792 	agi->agi_root = cpu_to_be32(fab[XREP_AGI_INOBT].root);
793 	agi->agi_level = cpu_to_be32(fab[XREP_AGI_INOBT].height);
794 
795 	if (xfs_has_finobt(sc->mp)) {
796 		agi->agi_free_root = cpu_to_be32(fab[XREP_AGI_FINOBT].root);
797 		agi->agi_free_level = cpu_to_be32(fab[XREP_AGI_FINOBT].height);
798 	}
799 }
800 
801 /* Update the AGI counters. */
802 STATIC int
803 xrep_agi_calc_from_btrees(
804 	struct xfs_scrub	*sc,
805 	struct xfs_buf		*agi_bp)
806 {
807 	struct xfs_btree_cur	*cur;
808 	struct xfs_agi		*agi = agi_bp->b_addr;
809 	struct xfs_mount	*mp = sc->mp;
810 	xfs_agino_t		count;
811 	xfs_agino_t		freecount;
812 	int			error;
813 
814 	cur = xfs_inobt_init_cursor(mp, sc->tp, agi_bp,
815 			sc->sa.pag, XFS_BTNUM_INO);
816 	error = xfs_ialloc_count_inodes(cur, &count, &freecount);
817 	if (error)
818 		goto err;
819 	if (xfs_has_inobtcounts(mp)) {
820 		xfs_agblock_t	blocks;
821 
822 		error = xfs_btree_count_blocks(cur, &blocks);
823 		if (error)
824 			goto err;
825 		agi->agi_iblocks = cpu_to_be32(blocks);
826 	}
827 	xfs_btree_del_cursor(cur, error);
828 
829 	agi->agi_count = cpu_to_be32(count);
830 	agi->agi_freecount = cpu_to_be32(freecount);
831 
832 	if (xfs_has_finobt(mp) && xfs_has_inobtcounts(mp)) {
833 		xfs_agblock_t	blocks;
834 
835 		cur = xfs_inobt_init_cursor(mp, sc->tp, agi_bp,
836 				sc->sa.pag, XFS_BTNUM_FINO);
837 		error = xfs_btree_count_blocks(cur, &blocks);
838 		if (error)
839 			goto err;
840 		xfs_btree_del_cursor(cur, error);
841 		agi->agi_fblocks = cpu_to_be32(blocks);
842 	}
843 
844 	return 0;
845 err:
846 	xfs_btree_del_cursor(cur, error);
847 	return error;
848 }
849 
850 /* Trigger reinitialization of the in-core data. */
851 STATIC int
852 xrep_agi_commit_new(
853 	struct xfs_scrub	*sc,
854 	struct xfs_buf		*agi_bp)
855 {
856 	struct xfs_perag	*pag;
857 	struct xfs_agi		*agi = agi_bp->b_addr;
858 
859 	/* Trigger inode count recalculation */
860 	xfs_force_summary_recalc(sc->mp);
861 
862 	/* Write this to disk. */
863 	xfs_trans_buf_set_type(sc->tp, agi_bp, XFS_BLFT_AGI_BUF);
864 	xfs_trans_log_buf(sc->tp, agi_bp, 0, BBTOB(agi_bp->b_length) - 1);
865 
866 	/* Now reinitialize the in-core counters if necessary. */
867 	pag = sc->sa.pag;
868 	pag->pagi_count = be32_to_cpu(agi->agi_count);
869 	pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
870 	pag->pagi_init = 1;
871 
872 	return 0;
873 }
874 
875 /* Repair the AGI. */
876 int
877 xrep_agi(
878 	struct xfs_scrub		*sc)
879 {
880 	struct xrep_find_ag_btree	fab[XREP_AGI_MAX] = {
881 		[XREP_AGI_INOBT] = {
882 			.rmap_owner = XFS_RMAP_OWN_INOBT,
883 			.buf_ops = &xfs_inobt_buf_ops,
884 		},
885 		[XREP_AGI_FINOBT] = {
886 			.rmap_owner = XFS_RMAP_OWN_INOBT,
887 			.buf_ops = &xfs_finobt_buf_ops,
888 		},
889 		[XREP_AGI_END] = {
890 			.buf_ops = NULL
891 		},
892 	};
893 	struct xfs_agi			old_agi;
894 	struct xfs_mount		*mp = sc->mp;
895 	struct xfs_buf			*agi_bp;
896 	struct xfs_agi			*agi;
897 	int				error;
898 
899 	/* We require the rmapbt to rebuild anything. */
900 	if (!xfs_has_rmapbt(mp))
901 		return -EOPNOTSUPP;
902 
903 	/*
904 	 * Make sure we have the AGI buffer, as scrub might have decided it
905 	 * was corrupt after xfs_ialloc_read_agi failed with -EFSCORRUPTED.
906 	 */
907 	error = xfs_trans_read_buf(mp, sc->tp, mp->m_ddev_targp,
908 			XFS_AG_DADDR(mp, sc->sa.pag->pag_agno,
909 						XFS_AGI_DADDR(mp)),
910 			XFS_FSS_TO_BB(mp, 1), 0, &agi_bp, NULL);
911 	if (error)
912 		return error;
913 	agi_bp->b_ops = &xfs_agi_buf_ops;
914 	agi = agi_bp->b_addr;
915 
916 	/* Find the AGI btree roots. */
917 	error = xrep_agi_find_btrees(sc, fab);
918 	if (error)
919 		return error;
920 
921 	/* Start rewriting the header and implant the btrees we found. */
922 	xrep_agi_init_header(sc, agi_bp, &old_agi);
923 	xrep_agi_set_roots(sc, agi, fab);
924 	error = xrep_agi_calc_from_btrees(sc, agi_bp);
925 	if (error)
926 		goto out_revert;
927 
928 	/* Reinitialize in-core state. */
929 	return xrep_agi_commit_new(sc, agi_bp);
930 
931 out_revert:
932 	/* Mark the incore AGI state stale and revert the AGI. */
933 	sc->sa.pag->pagi_init = 0;
934 	memcpy(agi, &old_agi, sizeof(old_agi));
935 	return error;
936 }
937