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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2016 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_log_format.h"
11#include "xfs_trans_resv.h"
12#include "xfs_mount.h"
13#include "xfs_defer.h"
14#include "xfs_btree.h"
15#include "xfs_bmap.h"
16#include "xfs_refcount_btree.h"
17#include "xfs_alloc.h"
18#include "xfs_errortag.h"
19#include "xfs_error.h"
20#include "xfs_trace.h"
21#include "xfs_trans.h"
22#include "xfs_bit.h"
23#include "xfs_refcount.h"
24#include "xfs_rmap.h"
25#include "xfs_ag.h"
26
27struct kmem_cache *xfs_refcount_intent_cache;
28
29/* Allowable refcount adjustment amounts. */
30enum xfs_refc_adjust_op {
31 XFS_REFCOUNT_ADJUST_INCREASE = 1,
32 XFS_REFCOUNT_ADJUST_DECREASE = -1,
33 XFS_REFCOUNT_ADJUST_COW_ALLOC = 0,
34 XFS_REFCOUNT_ADJUST_COW_FREE = -1,
35};
36
37STATIC int __xfs_refcount_cow_alloc(struct xfs_btree_cur *rcur,
38 xfs_agblock_t agbno, xfs_extlen_t aglen);
39STATIC int __xfs_refcount_cow_free(struct xfs_btree_cur *rcur,
40 xfs_agblock_t agbno, xfs_extlen_t aglen);
41
42/*
43 * Look up the first record less than or equal to [bno, len] in the btree
44 * given by cur.
45 */
46int
47xfs_refcount_lookup_le(
48 struct xfs_btree_cur *cur,
49 enum xfs_refc_domain domain,
50 xfs_agblock_t bno,
51 int *stat)
52{
53 trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_ag.pag->pag_agno,
54 xfs_refcount_encode_startblock(bno, domain),
55 XFS_LOOKUP_LE);
56 cur->bc_rec.rc.rc_startblock = bno;
57 cur->bc_rec.rc.rc_blockcount = 0;
58 cur->bc_rec.rc.rc_domain = domain;
59 return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
60}
61
62/*
63 * Look up the first record greater than or equal to [bno, len] in the btree
64 * given by cur.
65 */
66int
67xfs_refcount_lookup_ge(
68 struct xfs_btree_cur *cur,
69 enum xfs_refc_domain domain,
70 xfs_agblock_t bno,
71 int *stat)
72{
73 trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_ag.pag->pag_agno,
74 xfs_refcount_encode_startblock(bno, domain),
75 XFS_LOOKUP_GE);
76 cur->bc_rec.rc.rc_startblock = bno;
77 cur->bc_rec.rc.rc_blockcount = 0;
78 cur->bc_rec.rc.rc_domain = domain;
79 return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
80}
81
82/*
83 * Look up the first record equal to [bno, len] in the btree
84 * given by cur.
85 */
86int
87xfs_refcount_lookup_eq(
88 struct xfs_btree_cur *cur,
89 enum xfs_refc_domain domain,
90 xfs_agblock_t bno,
91 int *stat)
92{
93 trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_ag.pag->pag_agno,
94 xfs_refcount_encode_startblock(bno, domain),
95 XFS_LOOKUP_LE);
96 cur->bc_rec.rc.rc_startblock = bno;
97 cur->bc_rec.rc.rc_blockcount = 0;
98 cur->bc_rec.rc.rc_domain = domain;
99 return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
100}
101
102/* Convert on-disk record to in-core format. */
103void
104xfs_refcount_btrec_to_irec(
105 const union xfs_btree_rec *rec,
106 struct xfs_refcount_irec *irec)
107{
108 uint32_t start;
109
110 start = be32_to_cpu(rec->refc.rc_startblock);
111 if (start & XFS_REFC_COWFLAG) {
112 start &= ~XFS_REFC_COWFLAG;
113 irec->rc_domain = XFS_REFC_DOMAIN_COW;
114 } else {
115 irec->rc_domain = XFS_REFC_DOMAIN_SHARED;
116 }
117
118 irec->rc_startblock = start;
119 irec->rc_blockcount = be32_to_cpu(rec->refc.rc_blockcount);
120 irec->rc_refcount = be32_to_cpu(rec->refc.rc_refcount);
121}
122
123/*
124 * Get the data from the pointed-to record.
125 */
126int
127xfs_refcount_get_rec(
128 struct xfs_btree_cur *cur,
129 struct xfs_refcount_irec *irec,
130 int *stat)
131{
132 struct xfs_mount *mp = cur->bc_mp;
133 struct xfs_perag *pag = cur->bc_ag.pag;
134 union xfs_btree_rec *rec;
135 int error;
136
137 error = xfs_btree_get_rec(cur, &rec, stat);
138 if (error || !*stat)
139 return error;
140
141 xfs_refcount_btrec_to_irec(rec, irec);
142 if (irec->rc_blockcount == 0 || irec->rc_blockcount > MAXREFCEXTLEN)
143 goto out_bad_rec;
144
145 if (!xfs_refcount_check_domain(irec))
146 goto out_bad_rec;
147
148 /* check for valid extent range, including overflow */
149 if (!xfs_verify_agbext(pag, irec->rc_startblock, irec->rc_blockcount))
150 goto out_bad_rec;
151
152 if (irec->rc_refcount == 0 || irec->rc_refcount > MAXREFCOUNT)
153 goto out_bad_rec;
154
155 trace_xfs_refcount_get(cur->bc_mp, pag->pag_agno, irec);
156 return 0;
157
158out_bad_rec:
159 xfs_warn(mp,
160 "Refcount BTree record corruption in AG %d detected!",
161 pag->pag_agno);
162 xfs_warn(mp,
163 "Start block 0x%x, block count 0x%x, references 0x%x",
164 irec->rc_startblock, irec->rc_blockcount, irec->rc_refcount);
165 return -EFSCORRUPTED;
166}
167
168/*
169 * Update the record referred to by cur to the value given
170 * by [bno, len, refcount].
171 * This either works (return 0) or gets an EFSCORRUPTED error.
172 */
173STATIC int
174xfs_refcount_update(
175 struct xfs_btree_cur *cur,
176 struct xfs_refcount_irec *irec)
177{
178 union xfs_btree_rec rec;
179 uint32_t start;
180 int error;
181
182 trace_xfs_refcount_update(cur->bc_mp, cur->bc_ag.pag->pag_agno, irec);
183
184 start = xfs_refcount_encode_startblock(irec->rc_startblock,
185 irec->rc_domain);
186 rec.refc.rc_startblock = cpu_to_be32(start);
187 rec.refc.rc_blockcount = cpu_to_be32(irec->rc_blockcount);
188 rec.refc.rc_refcount = cpu_to_be32(irec->rc_refcount);
189
190 error = xfs_btree_update(cur, &rec);
191 if (error)
192 trace_xfs_refcount_update_error(cur->bc_mp,
193 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
194 return error;
195}
196
197/*
198 * Insert the record referred to by cur to the value given
199 * by [bno, len, refcount].
200 * This either works (return 0) or gets an EFSCORRUPTED error.
201 */
202int
203xfs_refcount_insert(
204 struct xfs_btree_cur *cur,
205 struct xfs_refcount_irec *irec,
206 int *i)
207{
208 int error;
209
210 trace_xfs_refcount_insert(cur->bc_mp, cur->bc_ag.pag->pag_agno, irec);
211
212 cur->bc_rec.rc.rc_startblock = irec->rc_startblock;
213 cur->bc_rec.rc.rc_blockcount = irec->rc_blockcount;
214 cur->bc_rec.rc.rc_refcount = irec->rc_refcount;
215 cur->bc_rec.rc.rc_domain = irec->rc_domain;
216
217 error = xfs_btree_insert(cur, i);
218 if (error)
219 goto out_error;
220 if (XFS_IS_CORRUPT(cur->bc_mp, *i != 1)) {
221 error = -EFSCORRUPTED;
222 goto out_error;
223 }
224
225out_error:
226 if (error)
227 trace_xfs_refcount_insert_error(cur->bc_mp,
228 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
229 return error;
230}
231
232/*
233 * Remove the record referred to by cur, then set the pointer to the spot
234 * where the record could be re-inserted, in case we want to increment or
235 * decrement the cursor.
236 * This either works (return 0) or gets an EFSCORRUPTED error.
237 */
238STATIC int
239xfs_refcount_delete(
240 struct xfs_btree_cur *cur,
241 int *i)
242{
243 struct xfs_refcount_irec irec;
244 int found_rec;
245 int error;
246
247 error = xfs_refcount_get_rec(cur, &irec, &found_rec);
248 if (error)
249 goto out_error;
250 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
251 error = -EFSCORRUPTED;
252 goto out_error;
253 }
254 trace_xfs_refcount_delete(cur->bc_mp, cur->bc_ag.pag->pag_agno, &irec);
255 error = xfs_btree_delete(cur, i);
256 if (XFS_IS_CORRUPT(cur->bc_mp, *i != 1)) {
257 error = -EFSCORRUPTED;
258 goto out_error;
259 }
260 if (error)
261 goto out_error;
262 error = xfs_refcount_lookup_ge(cur, irec.rc_domain, irec.rc_startblock,
263 &found_rec);
264out_error:
265 if (error)
266 trace_xfs_refcount_delete_error(cur->bc_mp,
267 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
268 return error;
269}
270
271/*
272 * Adjusting the Reference Count
273 *
274 * As stated elsewhere, the reference count btree (refcbt) stores
275 * >1 reference counts for extents of physical blocks. In this
276 * operation, we're either raising or lowering the reference count of
277 * some subrange stored in the tree:
278 *
279 * <------ adjustment range ------>
280 * ----+ +---+-----+ +--+--------+---------
281 * 2 | | 3 | 4 | |17| 55 | 10
282 * ----+ +---+-----+ +--+--------+---------
283 * X axis is physical blocks number;
284 * reference counts are the numbers inside the rectangles
285 *
286 * The first thing we need to do is to ensure that there are no
287 * refcount extents crossing either boundary of the range to be
288 * adjusted. For any extent that does cross a boundary, split it into
289 * two extents so that we can increment the refcount of one of the
290 * pieces later:
291 *
292 * <------ adjustment range ------>
293 * ----+ +---+-----+ +--+--------+----+----
294 * 2 | | 3 | 2 | |17| 55 | 10 | 10
295 * ----+ +---+-----+ +--+--------+----+----
296 *
297 * For this next step, let's assume that all the physical blocks in
298 * the adjustment range are mapped to a file and are therefore in use
299 * at least once. Therefore, we can infer that any gap in the
300 * refcount tree within the adjustment range represents a physical
301 * extent with refcount == 1:
302 *
303 * <------ adjustment range ------>
304 * ----+---+---+-----+-+--+--------+----+----
305 * 2 |"1"| 3 | 2 |1|17| 55 | 10 | 10
306 * ----+---+---+-----+-+--+--------+----+----
307 * ^
308 *
309 * For each extent that falls within the interval range, figure out
310 * which extent is to the left or the right of that extent. Now we
311 * have a left, current, and right extent. If the new reference count
312 * of the center extent enables us to merge left, center, and right
313 * into one record covering all three, do so. If the center extent is
314 * at the left end of the range, abuts the left extent, and its new
315 * reference count matches the left extent's record, then merge them.
316 * If the center extent is at the right end of the range, abuts the
317 * right extent, and the reference counts match, merge those. In the
318 * example, we can left merge (assuming an increment operation):
319 *
320 * <------ adjustment range ------>
321 * --------+---+-----+-+--+--------+----+----
322 * 2 | 3 | 2 |1|17| 55 | 10 | 10
323 * --------+---+-----+-+--+--------+----+----
324 * ^
325 *
326 * For all other extents within the range, adjust the reference count
327 * or delete it if the refcount falls below 2. If we were
328 * incrementing, the end result looks like this:
329 *
330 * <------ adjustment range ------>
331 * --------+---+-----+-+--+--------+----+----
332 * 2 | 4 | 3 |2|18| 56 | 11 | 10
333 * --------+---+-----+-+--+--------+----+----
334 *
335 * The result of a decrement operation looks as such:
336 *
337 * <------ adjustment range ------>
338 * ----+ +---+ +--+--------+----+----
339 * 2 | | 2 | |16| 54 | 9 | 10
340 * ----+ +---+ +--+--------+----+----
341 * DDDD 111111DD
342 *
343 * The blocks marked "D" are freed; the blocks marked "1" are only
344 * referenced once and therefore the record is removed from the
345 * refcount btree.
346 */
347
348/* Next block after this extent. */
349static inline xfs_agblock_t
350xfs_refc_next(
351 struct xfs_refcount_irec *rc)
352{
353 return rc->rc_startblock + rc->rc_blockcount;
354}
355
356/*
357 * Split a refcount extent that crosses agbno.
358 */
359STATIC int
360xfs_refcount_split_extent(
361 struct xfs_btree_cur *cur,
362 enum xfs_refc_domain domain,
363 xfs_agblock_t agbno,
364 bool *shape_changed)
365{
366 struct xfs_refcount_irec rcext, tmp;
367 int found_rec;
368 int error;
369
370 *shape_changed = false;
371 error = xfs_refcount_lookup_le(cur, domain, agbno, &found_rec);
372 if (error)
373 goto out_error;
374 if (!found_rec)
375 return 0;
376
377 error = xfs_refcount_get_rec(cur, &rcext, &found_rec);
378 if (error)
379 goto out_error;
380 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
381 error = -EFSCORRUPTED;
382 goto out_error;
383 }
384 if (rcext.rc_domain != domain)
385 return 0;
386 if (rcext.rc_startblock == agbno || xfs_refc_next(&rcext) <= agbno)
387 return 0;
388
389 *shape_changed = true;
390 trace_xfs_refcount_split_extent(cur->bc_mp, cur->bc_ag.pag->pag_agno,
391 &rcext, agbno);
392
393 /* Establish the right extent. */
394 tmp = rcext;
395 tmp.rc_startblock = agbno;
396 tmp.rc_blockcount -= (agbno - rcext.rc_startblock);
397 error = xfs_refcount_update(cur, &tmp);
398 if (error)
399 goto out_error;
400
401 /* Insert the left extent. */
402 tmp = rcext;
403 tmp.rc_blockcount = agbno - rcext.rc_startblock;
404 error = xfs_refcount_insert(cur, &tmp, &found_rec);
405 if (error)
406 goto out_error;
407 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
408 error = -EFSCORRUPTED;
409 goto out_error;
410 }
411 return error;
412
413out_error:
414 trace_xfs_refcount_split_extent_error(cur->bc_mp,
415 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
416 return error;
417}
418
419/*
420 * Merge the left, center, and right extents.
421 */
422STATIC int
423xfs_refcount_merge_center_extents(
424 struct xfs_btree_cur *cur,
425 struct xfs_refcount_irec *left,
426 struct xfs_refcount_irec *center,
427 struct xfs_refcount_irec *right,
428 unsigned long long extlen,
429 xfs_extlen_t *aglen)
430{
431 int error;
432 int found_rec;
433
434 trace_xfs_refcount_merge_center_extents(cur->bc_mp,
435 cur->bc_ag.pag->pag_agno, left, center, right);
436
437 ASSERT(left->rc_domain == center->rc_domain);
438 ASSERT(right->rc_domain == center->rc_domain);
439
440 /*
441 * Make sure the center and right extents are not in the btree.
442 * If the center extent was synthesized, the first delete call
443 * removes the right extent and we skip the second deletion.
444 * If center and right were in the btree, then the first delete
445 * call removes the center and the second one removes the right
446 * extent.
447 */
448 error = xfs_refcount_lookup_ge(cur, center->rc_domain,
449 center->rc_startblock, &found_rec);
450 if (error)
451 goto out_error;
452 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
453 error = -EFSCORRUPTED;
454 goto out_error;
455 }
456
457 error = xfs_refcount_delete(cur, &found_rec);
458 if (error)
459 goto out_error;
460 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
461 error = -EFSCORRUPTED;
462 goto out_error;
463 }
464
465 if (center->rc_refcount > 1) {
466 error = xfs_refcount_delete(cur, &found_rec);
467 if (error)
468 goto out_error;
469 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
470 error = -EFSCORRUPTED;
471 goto out_error;
472 }
473 }
474
475 /* Enlarge the left extent. */
476 error = xfs_refcount_lookup_le(cur, left->rc_domain,
477 left->rc_startblock, &found_rec);
478 if (error)
479 goto out_error;
480 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
481 error = -EFSCORRUPTED;
482 goto out_error;
483 }
484
485 left->rc_blockcount = extlen;
486 error = xfs_refcount_update(cur, left);
487 if (error)
488 goto out_error;
489
490 *aglen = 0;
491 return error;
492
493out_error:
494 trace_xfs_refcount_merge_center_extents_error(cur->bc_mp,
495 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
496 return error;
497}
498
499/*
500 * Merge with the left extent.
501 */
502STATIC int
503xfs_refcount_merge_left_extent(
504 struct xfs_btree_cur *cur,
505 struct xfs_refcount_irec *left,
506 struct xfs_refcount_irec *cleft,
507 xfs_agblock_t *agbno,
508 xfs_extlen_t *aglen)
509{
510 int error;
511 int found_rec;
512
513 trace_xfs_refcount_merge_left_extent(cur->bc_mp,
514 cur->bc_ag.pag->pag_agno, left, cleft);
515
516 ASSERT(left->rc_domain == cleft->rc_domain);
517
518 /* If the extent at agbno (cleft) wasn't synthesized, remove it. */
519 if (cleft->rc_refcount > 1) {
520 error = xfs_refcount_lookup_le(cur, cleft->rc_domain,
521 cleft->rc_startblock, &found_rec);
522 if (error)
523 goto out_error;
524 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
525 error = -EFSCORRUPTED;
526 goto out_error;
527 }
528
529 error = xfs_refcount_delete(cur, &found_rec);
530 if (error)
531 goto out_error;
532 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
533 error = -EFSCORRUPTED;
534 goto out_error;
535 }
536 }
537
538 /* Enlarge the left extent. */
539 error = xfs_refcount_lookup_le(cur, left->rc_domain,
540 left->rc_startblock, &found_rec);
541 if (error)
542 goto out_error;
543 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
544 error = -EFSCORRUPTED;
545 goto out_error;
546 }
547
548 left->rc_blockcount += cleft->rc_blockcount;
549 error = xfs_refcount_update(cur, left);
550 if (error)
551 goto out_error;
552
553 *agbno += cleft->rc_blockcount;
554 *aglen -= cleft->rc_blockcount;
555 return error;
556
557out_error:
558 trace_xfs_refcount_merge_left_extent_error(cur->bc_mp,
559 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
560 return error;
561}
562
563/*
564 * Merge with the right extent.
565 */
566STATIC int
567xfs_refcount_merge_right_extent(
568 struct xfs_btree_cur *cur,
569 struct xfs_refcount_irec *right,
570 struct xfs_refcount_irec *cright,
571 xfs_extlen_t *aglen)
572{
573 int error;
574 int found_rec;
575
576 trace_xfs_refcount_merge_right_extent(cur->bc_mp,
577 cur->bc_ag.pag->pag_agno, cright, right);
578
579 ASSERT(right->rc_domain == cright->rc_domain);
580
581 /*
582 * If the extent ending at agbno+aglen (cright) wasn't synthesized,
583 * remove it.
584 */
585 if (cright->rc_refcount > 1) {
586 error = xfs_refcount_lookup_le(cur, cright->rc_domain,
587 cright->rc_startblock, &found_rec);
588 if (error)
589 goto out_error;
590 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
591 error = -EFSCORRUPTED;
592 goto out_error;
593 }
594
595 error = xfs_refcount_delete(cur, &found_rec);
596 if (error)
597 goto out_error;
598 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
599 error = -EFSCORRUPTED;
600 goto out_error;
601 }
602 }
603
604 /* Enlarge the right extent. */
605 error = xfs_refcount_lookup_le(cur, right->rc_domain,
606 right->rc_startblock, &found_rec);
607 if (error)
608 goto out_error;
609 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
610 error = -EFSCORRUPTED;
611 goto out_error;
612 }
613
614 right->rc_startblock -= cright->rc_blockcount;
615 right->rc_blockcount += cright->rc_blockcount;
616 error = xfs_refcount_update(cur, right);
617 if (error)
618 goto out_error;
619
620 *aglen -= cright->rc_blockcount;
621 return error;
622
623out_error:
624 trace_xfs_refcount_merge_right_extent_error(cur->bc_mp,
625 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
626 return error;
627}
628
629/*
630 * Find the left extent and the one after it (cleft). This function assumes
631 * that we've already split any extent crossing agbno.
632 */
633STATIC int
634xfs_refcount_find_left_extents(
635 struct xfs_btree_cur *cur,
636 struct xfs_refcount_irec *left,
637 struct xfs_refcount_irec *cleft,
638 enum xfs_refc_domain domain,
639 xfs_agblock_t agbno,
640 xfs_extlen_t aglen)
641{
642 struct xfs_refcount_irec tmp;
643 int error;
644 int found_rec;
645
646 left->rc_startblock = cleft->rc_startblock = NULLAGBLOCK;
647 error = xfs_refcount_lookup_le(cur, domain, agbno - 1, &found_rec);
648 if (error)
649 goto out_error;
650 if (!found_rec)
651 return 0;
652
653 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
654 if (error)
655 goto out_error;
656 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
657 error = -EFSCORRUPTED;
658 goto out_error;
659 }
660
661 if (tmp.rc_domain != domain)
662 return 0;
663 if (xfs_refc_next(&tmp) != agbno)
664 return 0;
665 /* We have a left extent; retrieve (or invent) the next right one */
666 *left = tmp;
667
668 error = xfs_btree_increment(cur, 0, &found_rec);
669 if (error)
670 goto out_error;
671 if (found_rec) {
672 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
673 if (error)
674 goto out_error;
675 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
676 error = -EFSCORRUPTED;
677 goto out_error;
678 }
679
680 if (tmp.rc_domain != domain)
681 goto not_found;
682
683 /* if tmp starts at the end of our range, just use that */
684 if (tmp.rc_startblock == agbno)
685 *cleft = tmp;
686 else {
687 /*
688 * There's a gap in the refcntbt at the start of the
689 * range we're interested in (refcount == 1) so
690 * synthesize the implied extent and pass it back.
691 * We assume here that the agbno/aglen range was
692 * passed in from a data fork extent mapping and
693 * therefore is allocated to exactly one owner.
694 */
695 cleft->rc_startblock = agbno;
696 cleft->rc_blockcount = min(aglen,
697 tmp.rc_startblock - agbno);
698 cleft->rc_refcount = 1;
699 cleft->rc_domain = domain;
700 }
701 } else {
702not_found:
703 /*
704 * No extents, so pretend that there's one covering the whole
705 * range.
706 */
707 cleft->rc_startblock = agbno;
708 cleft->rc_blockcount = aglen;
709 cleft->rc_refcount = 1;
710 cleft->rc_domain = domain;
711 }
712 trace_xfs_refcount_find_left_extent(cur->bc_mp, cur->bc_ag.pag->pag_agno,
713 left, cleft, agbno);
714 return error;
715
716out_error:
717 trace_xfs_refcount_find_left_extent_error(cur->bc_mp,
718 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
719 return error;
720}
721
722/*
723 * Find the right extent and the one before it (cright). This function
724 * assumes that we've already split any extents crossing agbno + aglen.
725 */
726STATIC int
727xfs_refcount_find_right_extents(
728 struct xfs_btree_cur *cur,
729 struct xfs_refcount_irec *right,
730 struct xfs_refcount_irec *cright,
731 enum xfs_refc_domain domain,
732 xfs_agblock_t agbno,
733 xfs_extlen_t aglen)
734{
735 struct xfs_refcount_irec tmp;
736 int error;
737 int found_rec;
738
739 right->rc_startblock = cright->rc_startblock = NULLAGBLOCK;
740 error = xfs_refcount_lookup_ge(cur, domain, agbno + aglen, &found_rec);
741 if (error)
742 goto out_error;
743 if (!found_rec)
744 return 0;
745
746 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
747 if (error)
748 goto out_error;
749 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
750 error = -EFSCORRUPTED;
751 goto out_error;
752 }
753
754 if (tmp.rc_domain != domain)
755 return 0;
756 if (tmp.rc_startblock != agbno + aglen)
757 return 0;
758 /* We have a right extent; retrieve (or invent) the next left one */
759 *right = tmp;
760
761 error = xfs_btree_decrement(cur, 0, &found_rec);
762 if (error)
763 goto out_error;
764 if (found_rec) {
765 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
766 if (error)
767 goto out_error;
768 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
769 error = -EFSCORRUPTED;
770 goto out_error;
771 }
772
773 if (tmp.rc_domain != domain)
774 goto not_found;
775
776 /* if tmp ends at the end of our range, just use that */
777 if (xfs_refc_next(&tmp) == agbno + aglen)
778 *cright = tmp;
779 else {
780 /*
781 * There's a gap in the refcntbt at the end of the
782 * range we're interested in (refcount == 1) so
783 * create the implied extent and pass it back.
784 * We assume here that the agbno/aglen range was
785 * passed in from a data fork extent mapping and
786 * therefore is allocated to exactly one owner.
787 */
788 cright->rc_startblock = max(agbno, xfs_refc_next(&tmp));
789 cright->rc_blockcount = right->rc_startblock -
790 cright->rc_startblock;
791 cright->rc_refcount = 1;
792 cright->rc_domain = domain;
793 }
794 } else {
795not_found:
796 /*
797 * No extents, so pretend that there's one covering the whole
798 * range.
799 */
800 cright->rc_startblock = agbno;
801 cright->rc_blockcount = aglen;
802 cright->rc_refcount = 1;
803 cright->rc_domain = domain;
804 }
805 trace_xfs_refcount_find_right_extent(cur->bc_mp, cur->bc_ag.pag->pag_agno,
806 cright, right, agbno + aglen);
807 return error;
808
809out_error:
810 trace_xfs_refcount_find_right_extent_error(cur->bc_mp,
811 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
812 return error;
813}
814
815/* Is this extent valid? */
816static inline bool
817xfs_refc_valid(
818 const struct xfs_refcount_irec *rc)
819{
820 return rc->rc_startblock != NULLAGBLOCK;
821}
822
823static inline xfs_nlink_t
824xfs_refc_merge_refcount(
825 const struct xfs_refcount_irec *irec,
826 enum xfs_refc_adjust_op adjust)
827{
828 /* Once a record hits MAXREFCOUNT, it is pinned there forever */
829 if (irec->rc_refcount == MAXREFCOUNT)
830 return MAXREFCOUNT;
831 return irec->rc_refcount + adjust;
832}
833
834static inline bool
835xfs_refc_want_merge_center(
836 const struct xfs_refcount_irec *left,
837 const struct xfs_refcount_irec *cleft,
838 const struct xfs_refcount_irec *cright,
839 const struct xfs_refcount_irec *right,
840 bool cleft_is_cright,
841 enum xfs_refc_adjust_op adjust,
842 unsigned long long *ulenp)
843{
844 unsigned long long ulen = left->rc_blockcount;
845 xfs_nlink_t new_refcount;
846
847 /*
848 * To merge with a center record, both shoulder records must be
849 * adjacent to the record we want to adjust. This is only true if
850 * find_left and find_right made all four records valid.
851 */
852 if (!xfs_refc_valid(left) || !xfs_refc_valid(right) ||
853 !xfs_refc_valid(cleft) || !xfs_refc_valid(cright))
854 return false;
855
856 /* There must only be one record for the entire range. */
857 if (!cleft_is_cright)
858 return false;
859
860 /* The shoulder record refcounts must match the new refcount. */
861 new_refcount = xfs_refc_merge_refcount(cleft, adjust);
862 if (left->rc_refcount != new_refcount)
863 return false;
864 if (right->rc_refcount != new_refcount)
865 return false;
866
867 /*
868 * The new record cannot exceed the max length. ulen is a ULL as the
869 * individual record block counts can be up to (u32 - 1) in length
870 * hence we need to catch u32 addition overflows here.
871 */
872 ulen += cleft->rc_blockcount + right->rc_blockcount;
873 if (ulen >= MAXREFCEXTLEN)
874 return false;
875
876 *ulenp = ulen;
877 return true;
878}
879
880static inline bool
881xfs_refc_want_merge_left(
882 const struct xfs_refcount_irec *left,
883 const struct xfs_refcount_irec *cleft,
884 enum xfs_refc_adjust_op adjust)
885{
886 unsigned long long ulen = left->rc_blockcount;
887 xfs_nlink_t new_refcount;
888
889 /*
890 * For a left merge, the left shoulder record must be adjacent to the
891 * start of the range. If this is true, find_left made left and cleft
892 * contain valid contents.
893 */
894 if (!xfs_refc_valid(left) || !xfs_refc_valid(cleft))
895 return false;
896
897 /* Left shoulder record refcount must match the new refcount. */
898 new_refcount = xfs_refc_merge_refcount(cleft, adjust);
899 if (left->rc_refcount != new_refcount)
900 return false;
901
902 /*
903 * The new record cannot exceed the max length. ulen is a ULL as the
904 * individual record block counts can be up to (u32 - 1) in length
905 * hence we need to catch u32 addition overflows here.
906 */
907 ulen += cleft->rc_blockcount;
908 if (ulen >= MAXREFCEXTLEN)
909 return false;
910
911 return true;
912}
913
914static inline bool
915xfs_refc_want_merge_right(
916 const struct xfs_refcount_irec *cright,
917 const struct xfs_refcount_irec *right,
918 enum xfs_refc_adjust_op adjust)
919{
920 unsigned long long ulen = right->rc_blockcount;
921 xfs_nlink_t new_refcount;
922
923 /*
924 * For a right merge, the right shoulder record must be adjacent to the
925 * end of the range. If this is true, find_right made cright and right
926 * contain valid contents.
927 */
928 if (!xfs_refc_valid(right) || !xfs_refc_valid(cright))
929 return false;
930
931 /* Right shoulder record refcount must match the new refcount. */
932 new_refcount = xfs_refc_merge_refcount(cright, adjust);
933 if (right->rc_refcount != new_refcount)
934 return false;
935
936 /*
937 * The new record cannot exceed the max length. ulen is a ULL as the
938 * individual record block counts can be up to (u32 - 1) in length
939 * hence we need to catch u32 addition overflows here.
940 */
941 ulen += cright->rc_blockcount;
942 if (ulen >= MAXREFCEXTLEN)
943 return false;
944
945 return true;
946}
947
948/*
949 * Try to merge with any extents on the boundaries of the adjustment range.
950 */
951STATIC int
952xfs_refcount_merge_extents(
953 struct xfs_btree_cur *cur,
954 enum xfs_refc_domain domain,
955 xfs_agblock_t *agbno,
956 xfs_extlen_t *aglen,
957 enum xfs_refc_adjust_op adjust,
958 bool *shape_changed)
959{
960 struct xfs_refcount_irec left = {0}, cleft = {0};
961 struct xfs_refcount_irec cright = {0}, right = {0};
962 int error;
963 unsigned long long ulen;
964 bool cequal;
965
966 *shape_changed = false;
967 /*
968 * Find the extent just below agbno [left], just above agbno [cleft],
969 * just below (agbno + aglen) [cright], and just above (agbno + aglen)
970 * [right].
971 */
972 error = xfs_refcount_find_left_extents(cur, &left, &cleft, domain,
973 *agbno, *aglen);
974 if (error)
975 return error;
976 error = xfs_refcount_find_right_extents(cur, &right, &cright, domain,
977 *agbno, *aglen);
978 if (error)
979 return error;
980
981 /* No left or right extent to merge; exit. */
982 if (!xfs_refc_valid(&left) && !xfs_refc_valid(&right))
983 return 0;
984
985 cequal = (cleft.rc_startblock == cright.rc_startblock) &&
986 (cleft.rc_blockcount == cright.rc_blockcount);
987
988 /* Try to merge left, cleft, and right. cleft must == cright. */
989 if (xfs_refc_want_merge_center(&left, &cleft, &cright, &right, cequal,
990 adjust, &ulen)) {
991 *shape_changed = true;
992 return xfs_refcount_merge_center_extents(cur, &left, &cleft,
993 &right, ulen, aglen);
994 }
995
996 /* Try to merge left and cleft. */
997 if (xfs_refc_want_merge_left(&left, &cleft, adjust)) {
998 *shape_changed = true;
999 error = xfs_refcount_merge_left_extent(cur, &left, &cleft,
1000 agbno, aglen);
1001 if (error)
1002 return error;
1003
1004 /*
1005 * If we just merged left + cleft and cleft == cright,
1006 * we no longer have a cright to merge with right. We're done.
1007 */
1008 if (cequal)
1009 return 0;
1010 }
1011
1012 /* Try to merge cright and right. */
1013 if (xfs_refc_want_merge_right(&cright, &right, adjust)) {
1014 *shape_changed = true;
1015 return xfs_refcount_merge_right_extent(cur, &right, &cright,
1016 aglen);
1017 }
1018
1019 return 0;
1020}
1021
1022/*
1023 * XXX: This is a pretty hand-wavy estimate. The penalty for guessing
1024 * true incorrectly is a shutdown FS; the penalty for guessing false
1025 * incorrectly is more transaction rolls than might be necessary.
1026 * Be conservative here.
1027 */
1028static bool
1029xfs_refcount_still_have_space(
1030 struct xfs_btree_cur *cur)
1031{
1032 unsigned long overhead;
1033
1034 /*
1035 * Worst case estimate: full splits of the free space and rmap btrees
1036 * to handle each of the shape changes to the refcount btree.
1037 */
1038 overhead = xfs_allocfree_block_count(cur->bc_mp,
1039 cur->bc_ag.refc.shape_changes);
1040 overhead += cur->bc_mp->m_refc_maxlevels;
1041 overhead *= cur->bc_mp->m_sb.sb_blocksize;
1042
1043 /*
1044 * Only allow 2 refcount extent updates per transaction if the
1045 * refcount continue update "error" has been injected.
1046 */
1047 if (cur->bc_ag.refc.nr_ops > 2 &&
1048 XFS_TEST_ERROR(false, cur->bc_mp,
1049 XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE))
1050 return false;
1051
1052 if (cur->bc_ag.refc.nr_ops == 0)
1053 return true;
1054 else if (overhead > cur->bc_tp->t_log_res)
1055 return false;
1056 return cur->bc_tp->t_log_res - overhead >
1057 cur->bc_ag.refc.nr_ops * XFS_REFCOUNT_ITEM_OVERHEAD;
1058}
1059
1060/*
1061 * Adjust the refcounts of middle extents. At this point we should have
1062 * split extents that crossed the adjustment range; merged with adjacent
1063 * extents; and updated agbno/aglen to reflect the merges. Therefore,
1064 * all we have to do is update the extents inside [agbno, agbno + aglen].
1065 */
1066STATIC int
1067xfs_refcount_adjust_extents(
1068 struct xfs_btree_cur *cur,
1069 xfs_agblock_t *agbno,
1070 xfs_extlen_t *aglen,
1071 enum xfs_refc_adjust_op adj)
1072{
1073 struct xfs_refcount_irec ext, tmp;
1074 int error;
1075 int found_rec, found_tmp;
1076 xfs_fsblock_t fsbno;
1077
1078 /* Merging did all the work already. */
1079 if (*aglen == 0)
1080 return 0;
1081
1082 error = xfs_refcount_lookup_ge(cur, XFS_REFC_DOMAIN_SHARED, *agbno,
1083 &found_rec);
1084 if (error)
1085 goto out_error;
1086
1087 while (*aglen > 0 && xfs_refcount_still_have_space(cur)) {
1088 error = xfs_refcount_get_rec(cur, &ext, &found_rec);
1089 if (error)
1090 goto out_error;
1091 if (!found_rec || ext.rc_domain != XFS_REFC_DOMAIN_SHARED) {
1092 ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks;
1093 ext.rc_blockcount = 0;
1094 ext.rc_refcount = 0;
1095 ext.rc_domain = XFS_REFC_DOMAIN_SHARED;
1096 }
1097
1098 /*
1099 * Deal with a hole in the refcount tree; if a file maps to
1100 * these blocks and there's no refcountbt record, pretend that
1101 * there is one with refcount == 1.
1102 */
1103 if (ext.rc_startblock != *agbno) {
1104 tmp.rc_startblock = *agbno;
1105 tmp.rc_blockcount = min(*aglen,
1106 ext.rc_startblock - *agbno);
1107 tmp.rc_refcount = 1 + adj;
1108 tmp.rc_domain = XFS_REFC_DOMAIN_SHARED;
1109
1110 trace_xfs_refcount_modify_extent(cur->bc_mp,
1111 cur->bc_ag.pag->pag_agno, &tmp);
1112
1113 /*
1114 * Either cover the hole (increment) or
1115 * delete the range (decrement).
1116 */
1117 cur->bc_ag.refc.nr_ops++;
1118 if (tmp.rc_refcount) {
1119 error = xfs_refcount_insert(cur, &tmp,
1120 &found_tmp);
1121 if (error)
1122 goto out_error;
1123 if (XFS_IS_CORRUPT(cur->bc_mp,
1124 found_tmp != 1)) {
1125 error = -EFSCORRUPTED;
1126 goto out_error;
1127 }
1128 } else {
1129 fsbno = XFS_AGB_TO_FSB(cur->bc_mp,
1130 cur->bc_ag.pag->pag_agno,
1131 tmp.rc_startblock);
1132 xfs_free_extent_later(cur->bc_tp, fsbno,
1133 tmp.rc_blockcount, NULL);
1134 }
1135
1136 (*agbno) += tmp.rc_blockcount;
1137 (*aglen) -= tmp.rc_blockcount;
1138
1139 /* Stop if there's nothing left to modify */
1140 if (*aglen == 0 || !xfs_refcount_still_have_space(cur))
1141 break;
1142
1143 /* Move the cursor to the start of ext. */
1144 error = xfs_refcount_lookup_ge(cur,
1145 XFS_REFC_DOMAIN_SHARED, *agbno,
1146 &found_rec);
1147 if (error)
1148 goto out_error;
1149 }
1150
1151 /*
1152 * A previous step trimmed agbno/aglen such that the end of the
1153 * range would not be in the middle of the record. If this is
1154 * no longer the case, something is seriously wrong with the
1155 * btree. Make sure we never feed the synthesized record into
1156 * the processing loop below.
1157 */
1158 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount == 0) ||
1159 XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount > *aglen)) {
1160 error = -EFSCORRUPTED;
1161 goto out_error;
1162 }
1163
1164 /*
1165 * Adjust the reference count and either update the tree
1166 * (incr) or free the blocks (decr).
1167 */
1168 if (ext.rc_refcount == MAXREFCOUNT)
1169 goto skip;
1170 ext.rc_refcount += adj;
1171 trace_xfs_refcount_modify_extent(cur->bc_mp,
1172 cur->bc_ag.pag->pag_agno, &ext);
1173 cur->bc_ag.refc.nr_ops++;
1174 if (ext.rc_refcount > 1) {
1175 error = xfs_refcount_update(cur, &ext);
1176 if (error)
1177 goto out_error;
1178 } else if (ext.rc_refcount == 1) {
1179 error = xfs_refcount_delete(cur, &found_rec);
1180 if (error)
1181 goto out_error;
1182 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
1183 error = -EFSCORRUPTED;
1184 goto out_error;
1185 }
1186 goto advloop;
1187 } else {
1188 fsbno = XFS_AGB_TO_FSB(cur->bc_mp,
1189 cur->bc_ag.pag->pag_agno,
1190 ext.rc_startblock);
1191 xfs_free_extent_later(cur->bc_tp, fsbno,
1192 ext.rc_blockcount, NULL);
1193 }
1194
1195skip:
1196 error = xfs_btree_increment(cur, 0, &found_rec);
1197 if (error)
1198 goto out_error;
1199
1200advloop:
1201 (*agbno) += ext.rc_blockcount;
1202 (*aglen) -= ext.rc_blockcount;
1203 }
1204
1205 return error;
1206out_error:
1207 trace_xfs_refcount_modify_extent_error(cur->bc_mp,
1208 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
1209 return error;
1210}
1211
1212/* Adjust the reference count of a range of AG blocks. */
1213STATIC int
1214xfs_refcount_adjust(
1215 struct xfs_btree_cur *cur,
1216 xfs_agblock_t agbno,
1217 xfs_extlen_t aglen,
1218 xfs_agblock_t *new_agbno,
1219 xfs_extlen_t *new_aglen,
1220 enum xfs_refc_adjust_op adj)
1221{
1222 bool shape_changed;
1223 int shape_changes = 0;
1224 int error;
1225
1226 *new_agbno = agbno;
1227 *new_aglen = aglen;
1228 if (adj == XFS_REFCOUNT_ADJUST_INCREASE)
1229 trace_xfs_refcount_increase(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1230 agbno, aglen);
1231 else
1232 trace_xfs_refcount_decrease(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1233 agbno, aglen);
1234
1235 /*
1236 * Ensure that no rcextents cross the boundary of the adjustment range.
1237 */
1238 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_SHARED,
1239 agbno, &shape_changed);
1240 if (error)
1241 goto out_error;
1242 if (shape_changed)
1243 shape_changes++;
1244
1245 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_SHARED,
1246 agbno + aglen, &shape_changed);
1247 if (error)
1248 goto out_error;
1249 if (shape_changed)
1250 shape_changes++;
1251
1252 /*
1253 * Try to merge with the left or right extents of the range.
1254 */
1255 error = xfs_refcount_merge_extents(cur, XFS_REFC_DOMAIN_SHARED,
1256 new_agbno, new_aglen, adj, &shape_changed);
1257 if (error)
1258 goto out_error;
1259 if (shape_changed)
1260 shape_changes++;
1261 if (shape_changes)
1262 cur->bc_ag.refc.shape_changes++;
1263
1264 /* Now that we've taken care of the ends, adjust the middle extents */
1265 error = xfs_refcount_adjust_extents(cur, new_agbno, new_aglen, adj);
1266 if (error)
1267 goto out_error;
1268
1269 return 0;
1270
1271out_error:
1272 trace_xfs_refcount_adjust_error(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1273 error, _RET_IP_);
1274 return error;
1275}
1276
1277/* Clean up after calling xfs_refcount_finish_one. */
1278void
1279xfs_refcount_finish_one_cleanup(
1280 struct xfs_trans *tp,
1281 struct xfs_btree_cur *rcur,
1282 int error)
1283{
1284 struct xfs_buf *agbp;
1285
1286 if (rcur == NULL)
1287 return;
1288 agbp = rcur->bc_ag.agbp;
1289 xfs_btree_del_cursor(rcur, error);
1290 if (error)
1291 xfs_trans_brelse(tp, agbp);
1292}
1293
1294/*
1295 * Set up a continuation a deferred refcount operation by updating the intent.
1296 * Checks to make sure we're not going to run off the end of the AG.
1297 */
1298static inline int
1299xfs_refcount_continue_op(
1300 struct xfs_btree_cur *cur,
1301 xfs_fsblock_t startblock,
1302 xfs_agblock_t new_agbno,
1303 xfs_extlen_t new_len,
1304 xfs_fsblock_t *new_fsbno)
1305{
1306 struct xfs_mount *mp = cur->bc_mp;
1307 struct xfs_perag *pag = cur->bc_ag.pag;
1308
1309 if (XFS_IS_CORRUPT(mp, !xfs_verify_agbext(pag, new_agbno, new_len)))
1310 return -EFSCORRUPTED;
1311
1312 *new_fsbno = XFS_AGB_TO_FSB(mp, pag->pag_agno, new_agbno);
1313
1314 ASSERT(xfs_verify_fsbext(mp, *new_fsbno, new_len));
1315 ASSERT(pag->pag_agno == XFS_FSB_TO_AGNO(mp, *new_fsbno));
1316
1317 return 0;
1318}
1319
1320/*
1321 * Process one of the deferred refcount operations. We pass back the
1322 * btree cursor to maintain our lock on the btree between calls.
1323 * This saves time and eliminates a buffer deadlock between the
1324 * superblock and the AGF because we'll always grab them in the same
1325 * order.
1326 */
1327int
1328xfs_refcount_finish_one(
1329 struct xfs_trans *tp,
1330 enum xfs_refcount_intent_type type,
1331 xfs_fsblock_t startblock,
1332 xfs_extlen_t blockcount,
1333 xfs_fsblock_t *new_fsb,
1334 xfs_extlen_t *new_len,
1335 struct xfs_btree_cur **pcur)
1336{
1337 struct xfs_mount *mp = tp->t_mountp;
1338 struct xfs_btree_cur *rcur;
1339 struct xfs_buf *agbp = NULL;
1340 int error = 0;
1341 xfs_agblock_t bno;
1342 xfs_agblock_t new_agbno;
1343 unsigned long nr_ops = 0;
1344 int shape_changes = 0;
1345 struct xfs_perag *pag;
1346
1347 pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, startblock));
1348 bno = XFS_FSB_TO_AGBNO(mp, startblock);
1349
1350 trace_xfs_refcount_deferred(mp, XFS_FSB_TO_AGNO(mp, startblock),
1351 type, XFS_FSB_TO_AGBNO(mp, startblock),
1352 blockcount);
1353
1354 if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_REFCOUNT_FINISH_ONE)) {
1355 error = -EIO;
1356 goto out_drop;
1357 }
1358
1359 /*
1360 * If we haven't gotten a cursor or the cursor AG doesn't match
1361 * the startblock, get one now.
1362 */
1363 rcur = *pcur;
1364 if (rcur != NULL && rcur->bc_ag.pag != pag) {
1365 nr_ops = rcur->bc_ag.refc.nr_ops;
1366 shape_changes = rcur->bc_ag.refc.shape_changes;
1367 xfs_refcount_finish_one_cleanup(tp, rcur, 0);
1368 rcur = NULL;
1369 *pcur = NULL;
1370 }
1371 if (rcur == NULL) {
1372 error = xfs_alloc_read_agf(pag, tp, XFS_ALLOC_FLAG_FREEING,
1373 &agbp);
1374 if (error)
1375 goto out_drop;
1376
1377 rcur = xfs_refcountbt_init_cursor(mp, tp, agbp, pag);
1378 rcur->bc_ag.refc.nr_ops = nr_ops;
1379 rcur->bc_ag.refc.shape_changes = shape_changes;
1380 }
1381 *pcur = rcur;
1382
1383 switch (type) {
1384 case XFS_REFCOUNT_INCREASE:
1385 error = xfs_refcount_adjust(rcur, bno, blockcount, &new_agbno,
1386 new_len, XFS_REFCOUNT_ADJUST_INCREASE);
1387 if (error)
1388 goto out_drop;
1389 if (*new_len > 0)
1390 error = xfs_refcount_continue_op(rcur, startblock,
1391 new_agbno, *new_len, new_fsb);
1392 break;
1393 case XFS_REFCOUNT_DECREASE:
1394 error = xfs_refcount_adjust(rcur, bno, blockcount, &new_agbno,
1395 new_len, XFS_REFCOUNT_ADJUST_DECREASE);
1396 if (error)
1397 goto out_drop;
1398 if (*new_len > 0)
1399 error = xfs_refcount_continue_op(rcur, startblock,
1400 new_agbno, *new_len, new_fsb);
1401 break;
1402 case XFS_REFCOUNT_ALLOC_COW:
1403 *new_fsb = startblock + blockcount;
1404 *new_len = 0;
1405 error = __xfs_refcount_cow_alloc(rcur, bno, blockcount);
1406 break;
1407 case XFS_REFCOUNT_FREE_COW:
1408 *new_fsb = startblock + blockcount;
1409 *new_len = 0;
1410 error = __xfs_refcount_cow_free(rcur, bno, blockcount);
1411 break;
1412 default:
1413 ASSERT(0);
1414 error = -EFSCORRUPTED;
1415 }
1416 if (!error && *new_len > 0)
1417 trace_xfs_refcount_finish_one_leftover(mp, pag->pag_agno, type,
1418 bno, blockcount, new_agbno, *new_len);
1419out_drop:
1420 xfs_perag_put(pag);
1421 return error;
1422}
1423
1424/*
1425 * Record a refcount intent for later processing.
1426 */
1427static void
1428__xfs_refcount_add(
1429 struct xfs_trans *tp,
1430 enum xfs_refcount_intent_type type,
1431 xfs_fsblock_t startblock,
1432 xfs_extlen_t blockcount)
1433{
1434 struct xfs_refcount_intent *ri;
1435
1436 trace_xfs_refcount_defer(tp->t_mountp,
1437 XFS_FSB_TO_AGNO(tp->t_mountp, startblock),
1438 type, XFS_FSB_TO_AGBNO(tp->t_mountp, startblock),
1439 blockcount);
1440
1441 ri = kmem_cache_alloc(xfs_refcount_intent_cache,
1442 GFP_NOFS | __GFP_NOFAIL);
1443 INIT_LIST_HEAD(&ri->ri_list);
1444 ri->ri_type = type;
1445 ri->ri_startblock = startblock;
1446 ri->ri_blockcount = blockcount;
1447
1448 xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_REFCOUNT, &ri->ri_list);
1449}
1450
1451/*
1452 * Increase the reference count of the blocks backing a file's extent.
1453 */
1454void
1455xfs_refcount_increase_extent(
1456 struct xfs_trans *tp,
1457 struct xfs_bmbt_irec *PREV)
1458{
1459 if (!xfs_has_reflink(tp->t_mountp))
1460 return;
1461
1462 __xfs_refcount_add(tp, XFS_REFCOUNT_INCREASE, PREV->br_startblock,
1463 PREV->br_blockcount);
1464}
1465
1466/*
1467 * Decrease the reference count of the blocks backing a file's extent.
1468 */
1469void
1470xfs_refcount_decrease_extent(
1471 struct xfs_trans *tp,
1472 struct xfs_bmbt_irec *PREV)
1473{
1474 if (!xfs_has_reflink(tp->t_mountp))
1475 return;
1476
1477 __xfs_refcount_add(tp, XFS_REFCOUNT_DECREASE, PREV->br_startblock,
1478 PREV->br_blockcount);
1479}
1480
1481/*
1482 * Given an AG extent, find the lowest-numbered run of shared blocks
1483 * within that range and return the range in fbno/flen. If
1484 * find_end_of_shared is set, return the longest contiguous extent of
1485 * shared blocks; if not, just return the first extent we find. If no
1486 * shared blocks are found, fbno and flen will be set to NULLAGBLOCK
1487 * and 0, respectively.
1488 */
1489int
1490xfs_refcount_find_shared(
1491 struct xfs_btree_cur *cur,
1492 xfs_agblock_t agbno,
1493 xfs_extlen_t aglen,
1494 xfs_agblock_t *fbno,
1495 xfs_extlen_t *flen,
1496 bool find_end_of_shared)
1497{
1498 struct xfs_refcount_irec tmp;
1499 int i;
1500 int have;
1501 int error;
1502
1503 trace_xfs_refcount_find_shared(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1504 agbno, aglen);
1505
1506 /* By default, skip the whole range */
1507 *fbno = NULLAGBLOCK;
1508 *flen = 0;
1509
1510 /* Try to find a refcount extent that crosses the start */
1511 error = xfs_refcount_lookup_le(cur, XFS_REFC_DOMAIN_SHARED, agbno,
1512 &have);
1513 if (error)
1514 goto out_error;
1515 if (!have) {
1516 /* No left extent, look at the next one */
1517 error = xfs_btree_increment(cur, 0, &have);
1518 if (error)
1519 goto out_error;
1520 if (!have)
1521 goto done;
1522 }
1523 error = xfs_refcount_get_rec(cur, &tmp, &i);
1524 if (error)
1525 goto out_error;
1526 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
1527 error = -EFSCORRUPTED;
1528 goto out_error;
1529 }
1530 if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED)
1531 goto done;
1532
1533 /* If the extent ends before the start, look at the next one */
1534 if (tmp.rc_startblock + tmp.rc_blockcount <= agbno) {
1535 error = xfs_btree_increment(cur, 0, &have);
1536 if (error)
1537 goto out_error;
1538 if (!have)
1539 goto done;
1540 error = xfs_refcount_get_rec(cur, &tmp, &i);
1541 if (error)
1542 goto out_error;
1543 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
1544 error = -EFSCORRUPTED;
1545 goto out_error;
1546 }
1547 if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED)
1548 goto done;
1549 }
1550
1551 /* If the extent starts after the range we want, bail out */
1552 if (tmp.rc_startblock >= agbno + aglen)
1553 goto done;
1554
1555 /* We found the start of a shared extent! */
1556 if (tmp.rc_startblock < agbno) {
1557 tmp.rc_blockcount -= (agbno - tmp.rc_startblock);
1558 tmp.rc_startblock = agbno;
1559 }
1560
1561 *fbno = tmp.rc_startblock;
1562 *flen = min(tmp.rc_blockcount, agbno + aglen - *fbno);
1563 if (!find_end_of_shared)
1564 goto done;
1565
1566 /* Otherwise, find the end of this shared extent */
1567 while (*fbno + *flen < agbno + aglen) {
1568 error = xfs_btree_increment(cur, 0, &have);
1569 if (error)
1570 goto out_error;
1571 if (!have)
1572 break;
1573 error = xfs_refcount_get_rec(cur, &tmp, &i);
1574 if (error)
1575 goto out_error;
1576 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
1577 error = -EFSCORRUPTED;
1578 goto out_error;
1579 }
1580 if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED ||
1581 tmp.rc_startblock >= agbno + aglen ||
1582 tmp.rc_startblock != *fbno + *flen)
1583 break;
1584 *flen = min(*flen + tmp.rc_blockcount, agbno + aglen - *fbno);
1585 }
1586
1587done:
1588 trace_xfs_refcount_find_shared_result(cur->bc_mp,
1589 cur->bc_ag.pag->pag_agno, *fbno, *flen);
1590
1591out_error:
1592 if (error)
1593 trace_xfs_refcount_find_shared_error(cur->bc_mp,
1594 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
1595 return error;
1596}
1597
1598/*
1599 * Recovering CoW Blocks After a Crash
1600 *
1601 * Due to the way that the copy on write mechanism works, there's a window of
1602 * opportunity in which we can lose track of allocated blocks during a crash.
1603 * Because CoW uses delayed allocation in the in-core CoW fork, writeback
1604 * causes blocks to be allocated and stored in the CoW fork. The blocks are
1605 * no longer in the free space btree but are not otherwise recorded anywhere
1606 * until the write completes and the blocks are mapped into the file. A crash
1607 * in between allocation and remapping results in the replacement blocks being
1608 * lost. This situation is exacerbated by the CoW extent size hint because
1609 * allocations can hang around for long time.
1610 *
1611 * However, there is a place where we can record these allocations before they
1612 * become mappings -- the reference count btree. The btree does not record
1613 * extents with refcount == 1, so we can record allocations with a refcount of
1614 * 1. Blocks being used for CoW writeout cannot be shared, so there should be
1615 * no conflict with shared block records. These mappings should be created
1616 * when we allocate blocks to the CoW fork and deleted when they're removed
1617 * from the CoW fork.
1618 *
1619 * Minor nit: records for in-progress CoW allocations and records for shared
1620 * extents must never be merged, to preserve the property that (except for CoW
1621 * allocations) there are no refcount btree entries with refcount == 1. The
1622 * only time this could potentially happen is when unsharing a block that's
1623 * adjacent to CoW allocations, so we must be careful to avoid this.
1624 *
1625 * At mount time we recover lost CoW allocations by searching the refcount
1626 * btree for these refcount == 1 mappings. These represent CoW allocations
1627 * that were in progress at the time the filesystem went down, so we can free
1628 * them to get the space back.
1629 *
1630 * This mechanism is superior to creating EFIs for unmapped CoW extents for
1631 * several reasons -- first, EFIs pin the tail of the log and would have to be
1632 * periodically relogged to avoid filling up the log. Second, CoW completions
1633 * will have to file an EFD and create new EFIs for whatever remains in the
1634 * CoW fork; this partially takes care of (1) but extent-size reservations
1635 * will have to periodically relog even if there's no writeout in progress.
1636 * This can happen if the CoW extent size hint is set, which you really want.
1637 * Third, EFIs cannot currently be automatically relogged into newer
1638 * transactions to advance the log tail. Fourth, stuffing the log full of
1639 * EFIs places an upper bound on the number of CoW allocations that can be
1640 * held filesystem-wide at any given time. Recording them in the refcount
1641 * btree doesn't require us to maintain any state in memory and doesn't pin
1642 * the log.
1643 */
1644/*
1645 * Adjust the refcounts of CoW allocations. These allocations are "magic"
1646 * in that they're not referenced anywhere else in the filesystem, so we
1647 * stash them in the refcount btree with a refcount of 1 until either file
1648 * remapping (or CoW cancellation) happens.
1649 */
1650STATIC int
1651xfs_refcount_adjust_cow_extents(
1652 struct xfs_btree_cur *cur,
1653 xfs_agblock_t agbno,
1654 xfs_extlen_t aglen,
1655 enum xfs_refc_adjust_op adj)
1656{
1657 struct xfs_refcount_irec ext, tmp;
1658 int error;
1659 int found_rec, found_tmp;
1660
1661 if (aglen == 0)
1662 return 0;
1663
1664 /* Find any overlapping refcount records */
1665 error = xfs_refcount_lookup_ge(cur, XFS_REFC_DOMAIN_COW, agbno,
1666 &found_rec);
1667 if (error)
1668 goto out_error;
1669 error = xfs_refcount_get_rec(cur, &ext, &found_rec);
1670 if (error)
1671 goto out_error;
1672 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec &&
1673 ext.rc_domain != XFS_REFC_DOMAIN_COW)) {
1674 error = -EFSCORRUPTED;
1675 goto out_error;
1676 }
1677 if (!found_rec) {
1678 ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks;
1679 ext.rc_blockcount = 0;
1680 ext.rc_refcount = 0;
1681 ext.rc_domain = XFS_REFC_DOMAIN_COW;
1682 }
1683
1684 switch (adj) {
1685 case XFS_REFCOUNT_ADJUST_COW_ALLOC:
1686 /* Adding a CoW reservation, there should be nothing here. */
1687 if (XFS_IS_CORRUPT(cur->bc_mp,
1688 agbno + aglen > ext.rc_startblock)) {
1689 error = -EFSCORRUPTED;
1690 goto out_error;
1691 }
1692
1693 tmp.rc_startblock = agbno;
1694 tmp.rc_blockcount = aglen;
1695 tmp.rc_refcount = 1;
1696 tmp.rc_domain = XFS_REFC_DOMAIN_COW;
1697
1698 trace_xfs_refcount_modify_extent(cur->bc_mp,
1699 cur->bc_ag.pag->pag_agno, &tmp);
1700
1701 error = xfs_refcount_insert(cur, &tmp,
1702 &found_tmp);
1703 if (error)
1704 goto out_error;
1705 if (XFS_IS_CORRUPT(cur->bc_mp, found_tmp != 1)) {
1706 error = -EFSCORRUPTED;
1707 goto out_error;
1708 }
1709 break;
1710 case XFS_REFCOUNT_ADJUST_COW_FREE:
1711 /* Removing a CoW reservation, there should be one extent. */
1712 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_startblock != agbno)) {
1713 error = -EFSCORRUPTED;
1714 goto out_error;
1715 }
1716 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount != aglen)) {
1717 error = -EFSCORRUPTED;
1718 goto out_error;
1719 }
1720 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_refcount != 1)) {
1721 error = -EFSCORRUPTED;
1722 goto out_error;
1723 }
1724
1725 ext.rc_refcount = 0;
1726 trace_xfs_refcount_modify_extent(cur->bc_mp,
1727 cur->bc_ag.pag->pag_agno, &ext);
1728 error = xfs_refcount_delete(cur, &found_rec);
1729 if (error)
1730 goto out_error;
1731 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
1732 error = -EFSCORRUPTED;
1733 goto out_error;
1734 }
1735 break;
1736 default:
1737 ASSERT(0);
1738 }
1739
1740 return error;
1741out_error:
1742 trace_xfs_refcount_modify_extent_error(cur->bc_mp,
1743 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
1744 return error;
1745}
1746
1747/*
1748 * Add or remove refcount btree entries for CoW reservations.
1749 */
1750STATIC int
1751xfs_refcount_adjust_cow(
1752 struct xfs_btree_cur *cur,
1753 xfs_agblock_t agbno,
1754 xfs_extlen_t aglen,
1755 enum xfs_refc_adjust_op adj)
1756{
1757 bool shape_changed;
1758 int error;
1759
1760 /*
1761 * Ensure that no rcextents cross the boundary of the adjustment range.
1762 */
1763 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_COW,
1764 agbno, &shape_changed);
1765 if (error)
1766 goto out_error;
1767
1768 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_COW,
1769 agbno + aglen, &shape_changed);
1770 if (error)
1771 goto out_error;
1772
1773 /*
1774 * Try to merge with the left or right extents of the range.
1775 */
1776 error = xfs_refcount_merge_extents(cur, XFS_REFC_DOMAIN_COW, &agbno,
1777 &aglen, adj, &shape_changed);
1778 if (error)
1779 goto out_error;
1780
1781 /* Now that we've taken care of the ends, adjust the middle extents */
1782 error = xfs_refcount_adjust_cow_extents(cur, agbno, aglen, adj);
1783 if (error)
1784 goto out_error;
1785
1786 return 0;
1787
1788out_error:
1789 trace_xfs_refcount_adjust_cow_error(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1790 error, _RET_IP_);
1791 return error;
1792}
1793
1794/*
1795 * Record a CoW allocation in the refcount btree.
1796 */
1797STATIC int
1798__xfs_refcount_cow_alloc(
1799 struct xfs_btree_cur *rcur,
1800 xfs_agblock_t agbno,
1801 xfs_extlen_t aglen)
1802{
1803 trace_xfs_refcount_cow_increase(rcur->bc_mp, rcur->bc_ag.pag->pag_agno,
1804 agbno, aglen);
1805
1806 /* Add refcount btree reservation */
1807 return xfs_refcount_adjust_cow(rcur, agbno, aglen,
1808 XFS_REFCOUNT_ADJUST_COW_ALLOC);
1809}
1810
1811/*
1812 * Remove a CoW allocation from the refcount btree.
1813 */
1814STATIC int
1815__xfs_refcount_cow_free(
1816 struct xfs_btree_cur *rcur,
1817 xfs_agblock_t agbno,
1818 xfs_extlen_t aglen)
1819{
1820 trace_xfs_refcount_cow_decrease(rcur->bc_mp, rcur->bc_ag.pag->pag_agno,
1821 agbno, aglen);
1822
1823 /* Remove refcount btree reservation */
1824 return xfs_refcount_adjust_cow(rcur, agbno, aglen,
1825 XFS_REFCOUNT_ADJUST_COW_FREE);
1826}
1827
1828/* Record a CoW staging extent in the refcount btree. */
1829void
1830xfs_refcount_alloc_cow_extent(
1831 struct xfs_trans *tp,
1832 xfs_fsblock_t fsb,
1833 xfs_extlen_t len)
1834{
1835 struct xfs_mount *mp = tp->t_mountp;
1836
1837 if (!xfs_has_reflink(mp))
1838 return;
1839
1840 __xfs_refcount_add(tp, XFS_REFCOUNT_ALLOC_COW, fsb, len);
1841
1842 /* Add rmap entry */
1843 xfs_rmap_alloc_extent(tp, XFS_FSB_TO_AGNO(mp, fsb),
1844 XFS_FSB_TO_AGBNO(mp, fsb), len, XFS_RMAP_OWN_COW);
1845}
1846
1847/* Forget a CoW staging event in the refcount btree. */
1848void
1849xfs_refcount_free_cow_extent(
1850 struct xfs_trans *tp,
1851 xfs_fsblock_t fsb,
1852 xfs_extlen_t len)
1853{
1854 struct xfs_mount *mp = tp->t_mountp;
1855
1856 if (!xfs_has_reflink(mp))
1857 return;
1858
1859 /* Remove rmap entry */
1860 xfs_rmap_free_extent(tp, XFS_FSB_TO_AGNO(mp, fsb),
1861 XFS_FSB_TO_AGBNO(mp, fsb), len, XFS_RMAP_OWN_COW);
1862 __xfs_refcount_add(tp, XFS_REFCOUNT_FREE_COW, fsb, len);
1863}
1864
1865struct xfs_refcount_recovery {
1866 struct list_head rr_list;
1867 struct xfs_refcount_irec rr_rrec;
1868};
1869
1870/* Stuff an extent on the recovery list. */
1871STATIC int
1872xfs_refcount_recover_extent(
1873 struct xfs_btree_cur *cur,
1874 const union xfs_btree_rec *rec,
1875 void *priv)
1876{
1877 struct list_head *debris = priv;
1878 struct xfs_refcount_recovery *rr;
1879
1880 if (XFS_IS_CORRUPT(cur->bc_mp,
1881 be32_to_cpu(rec->refc.rc_refcount) != 1))
1882 return -EFSCORRUPTED;
1883
1884 rr = kmalloc(sizeof(struct xfs_refcount_recovery),
1885 GFP_KERNEL | __GFP_NOFAIL);
1886 INIT_LIST_HEAD(&rr->rr_list);
1887 xfs_refcount_btrec_to_irec(rec, &rr->rr_rrec);
1888
1889 if (XFS_IS_CORRUPT(cur->bc_mp,
1890 rr->rr_rrec.rc_domain != XFS_REFC_DOMAIN_COW)) {
1891 kfree(rr);
1892 return -EFSCORRUPTED;
1893 }
1894
1895 list_add_tail(&rr->rr_list, debris);
1896 return 0;
1897}
1898
1899/* Find and remove leftover CoW reservations. */
1900int
1901xfs_refcount_recover_cow_leftovers(
1902 struct xfs_mount *mp,
1903 struct xfs_perag *pag)
1904{
1905 struct xfs_trans *tp;
1906 struct xfs_btree_cur *cur;
1907 struct xfs_buf *agbp;
1908 struct xfs_refcount_recovery *rr, *n;
1909 struct list_head debris;
1910 union xfs_btree_irec low;
1911 union xfs_btree_irec high;
1912 xfs_fsblock_t fsb;
1913 int error;
1914
1915 /* reflink filesystems mustn't have AGs larger than 2^31-1 blocks */
1916 BUILD_BUG_ON(XFS_MAX_CRC_AG_BLOCKS >= XFS_REFC_COWFLAG);
1917 if (mp->m_sb.sb_agblocks > XFS_MAX_CRC_AG_BLOCKS)
1918 return -EOPNOTSUPP;
1919
1920 INIT_LIST_HEAD(&debris);
1921
1922 /*
1923 * In this first part, we use an empty transaction to gather up
1924 * all the leftover CoW extents so that we can subsequently
1925 * delete them. The empty transaction is used to avoid
1926 * a buffer lock deadlock if there happens to be a loop in the
1927 * refcountbt because we're allowed to re-grab a buffer that is
1928 * already attached to our transaction. When we're done
1929 * recording the CoW debris we cancel the (empty) transaction
1930 * and everything goes away cleanly.
1931 */
1932 error = xfs_trans_alloc_empty(mp, &tp);
1933 if (error)
1934 return error;
1935
1936 error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
1937 if (error)
1938 goto out_trans;
1939 cur = xfs_refcountbt_init_cursor(mp, tp, agbp, pag);
1940
1941 /* Find all the leftover CoW staging extents. */
1942 memset(&low, 0, sizeof(low));
1943 memset(&high, 0, sizeof(high));
1944 low.rc.rc_domain = high.rc.rc_domain = XFS_REFC_DOMAIN_COW;
1945 high.rc.rc_startblock = -1U;
1946 error = xfs_btree_query_range(cur, &low, &high,
1947 xfs_refcount_recover_extent, &debris);
1948 xfs_btree_del_cursor(cur, error);
1949 xfs_trans_brelse(tp, agbp);
1950 xfs_trans_cancel(tp);
1951 if (error)
1952 goto out_free;
1953
1954 /* Now iterate the list to free the leftovers */
1955 list_for_each_entry_safe(rr, n, &debris, rr_list) {
1956 /* Set up transaction. */
1957 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
1958 if (error)
1959 goto out_free;
1960
1961 trace_xfs_refcount_recover_extent(mp, pag->pag_agno,
1962 &rr->rr_rrec);
1963
1964 /* Free the orphan record */
1965 fsb = XFS_AGB_TO_FSB(mp, pag->pag_agno,
1966 rr->rr_rrec.rc_startblock);
1967 xfs_refcount_free_cow_extent(tp, fsb,
1968 rr->rr_rrec.rc_blockcount);
1969
1970 /* Free the block. */
1971 xfs_free_extent_later(tp, fsb, rr->rr_rrec.rc_blockcount, NULL);
1972
1973 error = xfs_trans_commit(tp);
1974 if (error)
1975 goto out_free;
1976
1977 list_del(&rr->rr_list);
1978 kfree(rr);
1979 }
1980
1981 return error;
1982out_trans:
1983 xfs_trans_cancel(tp);
1984out_free:
1985 /* Free the leftover list */
1986 list_for_each_entry_safe(rr, n, &debris, rr_list) {
1987 list_del(&rr->rr_list);
1988 kfree(rr);
1989 }
1990 return error;
1991}
1992
1993/* Is there a record covering a given extent? */
1994int
1995xfs_refcount_has_record(
1996 struct xfs_btree_cur *cur,
1997 enum xfs_refc_domain domain,
1998 xfs_agblock_t bno,
1999 xfs_extlen_t len,
2000 bool *exists)
2001{
2002 union xfs_btree_irec low;
2003 union xfs_btree_irec high;
2004
2005 memset(&low, 0, sizeof(low));
2006 low.rc.rc_startblock = bno;
2007 memset(&high, 0xFF, sizeof(high));
2008 high.rc.rc_startblock = bno + len - 1;
2009 low.rc.rc_domain = high.rc.rc_domain = domain;
2010
2011 return xfs_btree_has_record(cur, &low, &high, exists);
2012}
2013
2014int __init
2015xfs_refcount_intent_init_cache(void)
2016{
2017 xfs_refcount_intent_cache = kmem_cache_create("xfs_refc_intent",
2018 sizeof(struct xfs_refcount_intent),
2019 0, 0, NULL);
2020
2021 return xfs_refcount_intent_cache != NULL ? 0 : -ENOMEM;
2022}
2023
2024void
2025xfs_refcount_intent_destroy_cache(void)
2026{
2027 kmem_cache_destroy(xfs_refcount_intent_cache);
2028 xfs_refcount_intent_cache = NULL;
2029}
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2016 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_log_format.h"
11#include "xfs_trans_resv.h"
12#include "xfs_mount.h"
13#include "xfs_defer.h"
14#include "xfs_btree.h"
15#include "xfs_bmap.h"
16#include "xfs_refcount_btree.h"
17#include "xfs_alloc.h"
18#include "xfs_errortag.h"
19#include "xfs_error.h"
20#include "xfs_trace.h"
21#include "xfs_trans.h"
22#include "xfs_bit.h"
23#include "xfs_refcount.h"
24#include "xfs_rmap.h"
25#include "xfs_ag.h"
26#include "xfs_health.h"
27
28struct kmem_cache *xfs_refcount_intent_cache;
29
30/* Allowable refcount adjustment amounts. */
31enum xfs_refc_adjust_op {
32 XFS_REFCOUNT_ADJUST_INCREASE = 1,
33 XFS_REFCOUNT_ADJUST_DECREASE = -1,
34 XFS_REFCOUNT_ADJUST_COW_ALLOC = 0,
35 XFS_REFCOUNT_ADJUST_COW_FREE = -1,
36};
37
38STATIC int __xfs_refcount_cow_alloc(struct xfs_btree_cur *rcur,
39 xfs_agblock_t agbno, xfs_extlen_t aglen);
40STATIC int __xfs_refcount_cow_free(struct xfs_btree_cur *rcur,
41 xfs_agblock_t agbno, xfs_extlen_t aglen);
42
43/*
44 * Look up the first record less than or equal to [bno, len] in the btree
45 * given by cur.
46 */
47int
48xfs_refcount_lookup_le(
49 struct xfs_btree_cur *cur,
50 enum xfs_refc_domain domain,
51 xfs_agblock_t bno,
52 int *stat)
53{
54 trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_ag.pag->pag_agno,
55 xfs_refcount_encode_startblock(bno, domain),
56 XFS_LOOKUP_LE);
57 cur->bc_rec.rc.rc_startblock = bno;
58 cur->bc_rec.rc.rc_blockcount = 0;
59 cur->bc_rec.rc.rc_domain = domain;
60 return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
61}
62
63/*
64 * Look up the first record greater than or equal to [bno, len] in the btree
65 * given by cur.
66 */
67int
68xfs_refcount_lookup_ge(
69 struct xfs_btree_cur *cur,
70 enum xfs_refc_domain domain,
71 xfs_agblock_t bno,
72 int *stat)
73{
74 trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_ag.pag->pag_agno,
75 xfs_refcount_encode_startblock(bno, domain),
76 XFS_LOOKUP_GE);
77 cur->bc_rec.rc.rc_startblock = bno;
78 cur->bc_rec.rc.rc_blockcount = 0;
79 cur->bc_rec.rc.rc_domain = domain;
80 return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
81}
82
83/*
84 * Look up the first record equal to [bno, len] in the btree
85 * given by cur.
86 */
87int
88xfs_refcount_lookup_eq(
89 struct xfs_btree_cur *cur,
90 enum xfs_refc_domain domain,
91 xfs_agblock_t bno,
92 int *stat)
93{
94 trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_ag.pag->pag_agno,
95 xfs_refcount_encode_startblock(bno, domain),
96 XFS_LOOKUP_LE);
97 cur->bc_rec.rc.rc_startblock = bno;
98 cur->bc_rec.rc.rc_blockcount = 0;
99 cur->bc_rec.rc.rc_domain = domain;
100 return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
101}
102
103/* Convert on-disk record to in-core format. */
104void
105xfs_refcount_btrec_to_irec(
106 const union xfs_btree_rec *rec,
107 struct xfs_refcount_irec *irec)
108{
109 uint32_t start;
110
111 start = be32_to_cpu(rec->refc.rc_startblock);
112 if (start & XFS_REFC_COWFLAG) {
113 start &= ~XFS_REFC_COWFLAG;
114 irec->rc_domain = XFS_REFC_DOMAIN_COW;
115 } else {
116 irec->rc_domain = XFS_REFC_DOMAIN_SHARED;
117 }
118
119 irec->rc_startblock = start;
120 irec->rc_blockcount = be32_to_cpu(rec->refc.rc_blockcount);
121 irec->rc_refcount = be32_to_cpu(rec->refc.rc_refcount);
122}
123
124/* Simple checks for refcount records. */
125xfs_failaddr_t
126xfs_refcount_check_irec(
127 struct xfs_perag *pag,
128 const struct xfs_refcount_irec *irec)
129{
130 if (irec->rc_blockcount == 0 || irec->rc_blockcount > MAXREFCEXTLEN)
131 return __this_address;
132
133 if (!xfs_refcount_check_domain(irec))
134 return __this_address;
135
136 /* check for valid extent range, including overflow */
137 if (!xfs_verify_agbext(pag, irec->rc_startblock, irec->rc_blockcount))
138 return __this_address;
139
140 if (irec->rc_refcount == 0 || irec->rc_refcount > MAXREFCOUNT)
141 return __this_address;
142
143 return NULL;
144}
145
146static inline int
147xfs_refcount_complain_bad_rec(
148 struct xfs_btree_cur *cur,
149 xfs_failaddr_t fa,
150 const struct xfs_refcount_irec *irec)
151{
152 struct xfs_mount *mp = cur->bc_mp;
153
154 xfs_warn(mp,
155 "Refcount BTree record corruption in AG %d detected at %pS!",
156 cur->bc_ag.pag->pag_agno, fa);
157 xfs_warn(mp,
158 "Start block 0x%x, block count 0x%x, references 0x%x",
159 irec->rc_startblock, irec->rc_blockcount, irec->rc_refcount);
160 xfs_btree_mark_sick(cur);
161 return -EFSCORRUPTED;
162}
163
164/*
165 * Get the data from the pointed-to record.
166 */
167int
168xfs_refcount_get_rec(
169 struct xfs_btree_cur *cur,
170 struct xfs_refcount_irec *irec,
171 int *stat)
172{
173 union xfs_btree_rec *rec;
174 xfs_failaddr_t fa;
175 int error;
176
177 error = xfs_btree_get_rec(cur, &rec, stat);
178 if (error || !*stat)
179 return error;
180
181 xfs_refcount_btrec_to_irec(rec, irec);
182 fa = xfs_refcount_check_irec(cur->bc_ag.pag, irec);
183 if (fa)
184 return xfs_refcount_complain_bad_rec(cur, fa, irec);
185
186 trace_xfs_refcount_get(cur->bc_mp, cur->bc_ag.pag->pag_agno, irec);
187 return 0;
188}
189
190/*
191 * Update the record referred to by cur to the value given
192 * by [bno, len, refcount].
193 * This either works (return 0) or gets an EFSCORRUPTED error.
194 */
195STATIC int
196xfs_refcount_update(
197 struct xfs_btree_cur *cur,
198 struct xfs_refcount_irec *irec)
199{
200 union xfs_btree_rec rec;
201 uint32_t start;
202 int error;
203
204 trace_xfs_refcount_update(cur->bc_mp, cur->bc_ag.pag->pag_agno, irec);
205
206 start = xfs_refcount_encode_startblock(irec->rc_startblock,
207 irec->rc_domain);
208 rec.refc.rc_startblock = cpu_to_be32(start);
209 rec.refc.rc_blockcount = cpu_to_be32(irec->rc_blockcount);
210 rec.refc.rc_refcount = cpu_to_be32(irec->rc_refcount);
211
212 error = xfs_btree_update(cur, &rec);
213 if (error)
214 trace_xfs_refcount_update_error(cur->bc_mp,
215 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
216 return error;
217}
218
219/*
220 * Insert the record referred to by cur to the value given
221 * by [bno, len, refcount].
222 * This either works (return 0) or gets an EFSCORRUPTED error.
223 */
224int
225xfs_refcount_insert(
226 struct xfs_btree_cur *cur,
227 struct xfs_refcount_irec *irec,
228 int *i)
229{
230 int error;
231
232 trace_xfs_refcount_insert(cur->bc_mp, cur->bc_ag.pag->pag_agno, irec);
233
234 cur->bc_rec.rc.rc_startblock = irec->rc_startblock;
235 cur->bc_rec.rc.rc_blockcount = irec->rc_blockcount;
236 cur->bc_rec.rc.rc_refcount = irec->rc_refcount;
237 cur->bc_rec.rc.rc_domain = irec->rc_domain;
238
239 error = xfs_btree_insert(cur, i);
240 if (error)
241 goto out_error;
242 if (XFS_IS_CORRUPT(cur->bc_mp, *i != 1)) {
243 xfs_btree_mark_sick(cur);
244 error = -EFSCORRUPTED;
245 goto out_error;
246 }
247
248out_error:
249 if (error)
250 trace_xfs_refcount_insert_error(cur->bc_mp,
251 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
252 return error;
253}
254
255/*
256 * Remove the record referred to by cur, then set the pointer to the spot
257 * where the record could be re-inserted, in case we want to increment or
258 * decrement the cursor.
259 * This either works (return 0) or gets an EFSCORRUPTED error.
260 */
261STATIC int
262xfs_refcount_delete(
263 struct xfs_btree_cur *cur,
264 int *i)
265{
266 struct xfs_refcount_irec irec;
267 int found_rec;
268 int error;
269
270 error = xfs_refcount_get_rec(cur, &irec, &found_rec);
271 if (error)
272 goto out_error;
273 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
274 xfs_btree_mark_sick(cur);
275 error = -EFSCORRUPTED;
276 goto out_error;
277 }
278 trace_xfs_refcount_delete(cur->bc_mp, cur->bc_ag.pag->pag_agno, &irec);
279 error = xfs_btree_delete(cur, i);
280 if (XFS_IS_CORRUPT(cur->bc_mp, *i != 1)) {
281 xfs_btree_mark_sick(cur);
282 error = -EFSCORRUPTED;
283 goto out_error;
284 }
285 if (error)
286 goto out_error;
287 error = xfs_refcount_lookup_ge(cur, irec.rc_domain, irec.rc_startblock,
288 &found_rec);
289out_error:
290 if (error)
291 trace_xfs_refcount_delete_error(cur->bc_mp,
292 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
293 return error;
294}
295
296/*
297 * Adjusting the Reference Count
298 *
299 * As stated elsewhere, the reference count btree (refcbt) stores
300 * >1 reference counts for extents of physical blocks. In this
301 * operation, we're either raising or lowering the reference count of
302 * some subrange stored in the tree:
303 *
304 * <------ adjustment range ------>
305 * ----+ +---+-----+ +--+--------+---------
306 * 2 | | 3 | 4 | |17| 55 | 10
307 * ----+ +---+-----+ +--+--------+---------
308 * X axis is physical blocks number;
309 * reference counts are the numbers inside the rectangles
310 *
311 * The first thing we need to do is to ensure that there are no
312 * refcount extents crossing either boundary of the range to be
313 * adjusted. For any extent that does cross a boundary, split it into
314 * two extents so that we can increment the refcount of one of the
315 * pieces later:
316 *
317 * <------ adjustment range ------>
318 * ----+ +---+-----+ +--+--------+----+----
319 * 2 | | 3 | 2 | |17| 55 | 10 | 10
320 * ----+ +---+-----+ +--+--------+----+----
321 *
322 * For this next step, let's assume that all the physical blocks in
323 * the adjustment range are mapped to a file and are therefore in use
324 * at least once. Therefore, we can infer that any gap in the
325 * refcount tree within the adjustment range represents a physical
326 * extent with refcount == 1:
327 *
328 * <------ adjustment range ------>
329 * ----+---+---+-----+-+--+--------+----+----
330 * 2 |"1"| 3 | 2 |1|17| 55 | 10 | 10
331 * ----+---+---+-----+-+--+--------+----+----
332 * ^
333 *
334 * For each extent that falls within the interval range, figure out
335 * which extent is to the left or the right of that extent. Now we
336 * have a left, current, and right extent. If the new reference count
337 * of the center extent enables us to merge left, center, and right
338 * into one record covering all three, do so. If the center extent is
339 * at the left end of the range, abuts the left extent, and its new
340 * reference count matches the left extent's record, then merge them.
341 * If the center extent is at the right end of the range, abuts the
342 * right extent, and the reference counts match, merge those. In the
343 * example, we can left merge (assuming an increment operation):
344 *
345 * <------ adjustment range ------>
346 * --------+---+-----+-+--+--------+----+----
347 * 2 | 3 | 2 |1|17| 55 | 10 | 10
348 * --------+---+-----+-+--+--------+----+----
349 * ^
350 *
351 * For all other extents within the range, adjust the reference count
352 * or delete it if the refcount falls below 2. If we were
353 * incrementing, the end result looks like this:
354 *
355 * <------ adjustment range ------>
356 * --------+---+-----+-+--+--------+----+----
357 * 2 | 4 | 3 |2|18| 56 | 11 | 10
358 * --------+---+-----+-+--+--------+----+----
359 *
360 * The result of a decrement operation looks as such:
361 *
362 * <------ adjustment range ------>
363 * ----+ +---+ +--+--------+----+----
364 * 2 | | 2 | |16| 54 | 9 | 10
365 * ----+ +---+ +--+--------+----+----
366 * DDDD 111111DD
367 *
368 * The blocks marked "D" are freed; the blocks marked "1" are only
369 * referenced once and therefore the record is removed from the
370 * refcount btree.
371 */
372
373/* Next block after this extent. */
374static inline xfs_agblock_t
375xfs_refc_next(
376 struct xfs_refcount_irec *rc)
377{
378 return rc->rc_startblock + rc->rc_blockcount;
379}
380
381/*
382 * Split a refcount extent that crosses agbno.
383 */
384STATIC int
385xfs_refcount_split_extent(
386 struct xfs_btree_cur *cur,
387 enum xfs_refc_domain domain,
388 xfs_agblock_t agbno,
389 bool *shape_changed)
390{
391 struct xfs_refcount_irec rcext, tmp;
392 int found_rec;
393 int error;
394
395 *shape_changed = false;
396 error = xfs_refcount_lookup_le(cur, domain, agbno, &found_rec);
397 if (error)
398 goto out_error;
399 if (!found_rec)
400 return 0;
401
402 error = xfs_refcount_get_rec(cur, &rcext, &found_rec);
403 if (error)
404 goto out_error;
405 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
406 xfs_btree_mark_sick(cur);
407 error = -EFSCORRUPTED;
408 goto out_error;
409 }
410 if (rcext.rc_domain != domain)
411 return 0;
412 if (rcext.rc_startblock == agbno || xfs_refc_next(&rcext) <= agbno)
413 return 0;
414
415 *shape_changed = true;
416 trace_xfs_refcount_split_extent(cur->bc_mp, cur->bc_ag.pag->pag_agno,
417 &rcext, agbno);
418
419 /* Establish the right extent. */
420 tmp = rcext;
421 tmp.rc_startblock = agbno;
422 tmp.rc_blockcount -= (agbno - rcext.rc_startblock);
423 error = xfs_refcount_update(cur, &tmp);
424 if (error)
425 goto out_error;
426
427 /* Insert the left extent. */
428 tmp = rcext;
429 tmp.rc_blockcount = agbno - rcext.rc_startblock;
430 error = xfs_refcount_insert(cur, &tmp, &found_rec);
431 if (error)
432 goto out_error;
433 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
434 xfs_btree_mark_sick(cur);
435 error = -EFSCORRUPTED;
436 goto out_error;
437 }
438 return error;
439
440out_error:
441 trace_xfs_refcount_split_extent_error(cur->bc_mp,
442 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
443 return error;
444}
445
446/*
447 * Merge the left, center, and right extents.
448 */
449STATIC int
450xfs_refcount_merge_center_extents(
451 struct xfs_btree_cur *cur,
452 struct xfs_refcount_irec *left,
453 struct xfs_refcount_irec *center,
454 struct xfs_refcount_irec *right,
455 unsigned long long extlen,
456 xfs_extlen_t *aglen)
457{
458 int error;
459 int found_rec;
460
461 trace_xfs_refcount_merge_center_extents(cur->bc_mp,
462 cur->bc_ag.pag->pag_agno, left, center, right);
463
464 ASSERT(left->rc_domain == center->rc_domain);
465 ASSERT(right->rc_domain == center->rc_domain);
466
467 /*
468 * Make sure the center and right extents are not in the btree.
469 * If the center extent was synthesized, the first delete call
470 * removes the right extent and we skip the second deletion.
471 * If center and right were in the btree, then the first delete
472 * call removes the center and the second one removes the right
473 * extent.
474 */
475 error = xfs_refcount_lookup_ge(cur, center->rc_domain,
476 center->rc_startblock, &found_rec);
477 if (error)
478 goto out_error;
479 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
480 xfs_btree_mark_sick(cur);
481 error = -EFSCORRUPTED;
482 goto out_error;
483 }
484
485 error = xfs_refcount_delete(cur, &found_rec);
486 if (error)
487 goto out_error;
488 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
489 xfs_btree_mark_sick(cur);
490 error = -EFSCORRUPTED;
491 goto out_error;
492 }
493
494 if (center->rc_refcount > 1) {
495 error = xfs_refcount_delete(cur, &found_rec);
496 if (error)
497 goto out_error;
498 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
499 xfs_btree_mark_sick(cur);
500 error = -EFSCORRUPTED;
501 goto out_error;
502 }
503 }
504
505 /* Enlarge the left extent. */
506 error = xfs_refcount_lookup_le(cur, left->rc_domain,
507 left->rc_startblock, &found_rec);
508 if (error)
509 goto out_error;
510 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
511 xfs_btree_mark_sick(cur);
512 error = -EFSCORRUPTED;
513 goto out_error;
514 }
515
516 left->rc_blockcount = extlen;
517 error = xfs_refcount_update(cur, left);
518 if (error)
519 goto out_error;
520
521 *aglen = 0;
522 return error;
523
524out_error:
525 trace_xfs_refcount_merge_center_extents_error(cur->bc_mp,
526 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
527 return error;
528}
529
530/*
531 * Merge with the left extent.
532 */
533STATIC int
534xfs_refcount_merge_left_extent(
535 struct xfs_btree_cur *cur,
536 struct xfs_refcount_irec *left,
537 struct xfs_refcount_irec *cleft,
538 xfs_agblock_t *agbno,
539 xfs_extlen_t *aglen)
540{
541 int error;
542 int found_rec;
543
544 trace_xfs_refcount_merge_left_extent(cur->bc_mp,
545 cur->bc_ag.pag->pag_agno, left, cleft);
546
547 ASSERT(left->rc_domain == cleft->rc_domain);
548
549 /* If the extent at agbno (cleft) wasn't synthesized, remove it. */
550 if (cleft->rc_refcount > 1) {
551 error = xfs_refcount_lookup_le(cur, cleft->rc_domain,
552 cleft->rc_startblock, &found_rec);
553 if (error)
554 goto out_error;
555 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
556 xfs_btree_mark_sick(cur);
557 error = -EFSCORRUPTED;
558 goto out_error;
559 }
560
561 error = xfs_refcount_delete(cur, &found_rec);
562 if (error)
563 goto out_error;
564 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
565 xfs_btree_mark_sick(cur);
566 error = -EFSCORRUPTED;
567 goto out_error;
568 }
569 }
570
571 /* Enlarge the left extent. */
572 error = xfs_refcount_lookup_le(cur, left->rc_domain,
573 left->rc_startblock, &found_rec);
574 if (error)
575 goto out_error;
576 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
577 xfs_btree_mark_sick(cur);
578 error = -EFSCORRUPTED;
579 goto out_error;
580 }
581
582 left->rc_blockcount += cleft->rc_blockcount;
583 error = xfs_refcount_update(cur, left);
584 if (error)
585 goto out_error;
586
587 *agbno += cleft->rc_blockcount;
588 *aglen -= cleft->rc_blockcount;
589 return error;
590
591out_error:
592 trace_xfs_refcount_merge_left_extent_error(cur->bc_mp,
593 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
594 return error;
595}
596
597/*
598 * Merge with the right extent.
599 */
600STATIC int
601xfs_refcount_merge_right_extent(
602 struct xfs_btree_cur *cur,
603 struct xfs_refcount_irec *right,
604 struct xfs_refcount_irec *cright,
605 xfs_extlen_t *aglen)
606{
607 int error;
608 int found_rec;
609
610 trace_xfs_refcount_merge_right_extent(cur->bc_mp,
611 cur->bc_ag.pag->pag_agno, cright, right);
612
613 ASSERT(right->rc_domain == cright->rc_domain);
614
615 /*
616 * If the extent ending at agbno+aglen (cright) wasn't synthesized,
617 * remove it.
618 */
619 if (cright->rc_refcount > 1) {
620 error = xfs_refcount_lookup_le(cur, cright->rc_domain,
621 cright->rc_startblock, &found_rec);
622 if (error)
623 goto out_error;
624 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
625 xfs_btree_mark_sick(cur);
626 error = -EFSCORRUPTED;
627 goto out_error;
628 }
629
630 error = xfs_refcount_delete(cur, &found_rec);
631 if (error)
632 goto out_error;
633 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
634 xfs_btree_mark_sick(cur);
635 error = -EFSCORRUPTED;
636 goto out_error;
637 }
638 }
639
640 /* Enlarge the right extent. */
641 error = xfs_refcount_lookup_le(cur, right->rc_domain,
642 right->rc_startblock, &found_rec);
643 if (error)
644 goto out_error;
645 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
646 xfs_btree_mark_sick(cur);
647 error = -EFSCORRUPTED;
648 goto out_error;
649 }
650
651 right->rc_startblock -= cright->rc_blockcount;
652 right->rc_blockcount += cright->rc_blockcount;
653 error = xfs_refcount_update(cur, right);
654 if (error)
655 goto out_error;
656
657 *aglen -= cright->rc_blockcount;
658 return error;
659
660out_error:
661 trace_xfs_refcount_merge_right_extent_error(cur->bc_mp,
662 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
663 return error;
664}
665
666/*
667 * Find the left extent and the one after it (cleft). This function assumes
668 * that we've already split any extent crossing agbno.
669 */
670STATIC int
671xfs_refcount_find_left_extents(
672 struct xfs_btree_cur *cur,
673 struct xfs_refcount_irec *left,
674 struct xfs_refcount_irec *cleft,
675 enum xfs_refc_domain domain,
676 xfs_agblock_t agbno,
677 xfs_extlen_t aglen)
678{
679 struct xfs_refcount_irec tmp;
680 int error;
681 int found_rec;
682
683 left->rc_startblock = cleft->rc_startblock = NULLAGBLOCK;
684 error = xfs_refcount_lookup_le(cur, domain, agbno - 1, &found_rec);
685 if (error)
686 goto out_error;
687 if (!found_rec)
688 return 0;
689
690 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
691 if (error)
692 goto out_error;
693 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
694 xfs_btree_mark_sick(cur);
695 error = -EFSCORRUPTED;
696 goto out_error;
697 }
698
699 if (tmp.rc_domain != domain)
700 return 0;
701 if (xfs_refc_next(&tmp) != agbno)
702 return 0;
703 /* We have a left extent; retrieve (or invent) the next right one */
704 *left = tmp;
705
706 error = xfs_btree_increment(cur, 0, &found_rec);
707 if (error)
708 goto out_error;
709 if (found_rec) {
710 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
711 if (error)
712 goto out_error;
713 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
714 xfs_btree_mark_sick(cur);
715 error = -EFSCORRUPTED;
716 goto out_error;
717 }
718
719 if (tmp.rc_domain != domain)
720 goto not_found;
721
722 /* if tmp starts at the end of our range, just use that */
723 if (tmp.rc_startblock == agbno)
724 *cleft = tmp;
725 else {
726 /*
727 * There's a gap in the refcntbt at the start of the
728 * range we're interested in (refcount == 1) so
729 * synthesize the implied extent and pass it back.
730 * We assume here that the agbno/aglen range was
731 * passed in from a data fork extent mapping and
732 * therefore is allocated to exactly one owner.
733 */
734 cleft->rc_startblock = agbno;
735 cleft->rc_blockcount = min(aglen,
736 tmp.rc_startblock - agbno);
737 cleft->rc_refcount = 1;
738 cleft->rc_domain = domain;
739 }
740 } else {
741not_found:
742 /*
743 * No extents, so pretend that there's one covering the whole
744 * range.
745 */
746 cleft->rc_startblock = agbno;
747 cleft->rc_blockcount = aglen;
748 cleft->rc_refcount = 1;
749 cleft->rc_domain = domain;
750 }
751 trace_xfs_refcount_find_left_extent(cur->bc_mp, cur->bc_ag.pag->pag_agno,
752 left, cleft, agbno);
753 return error;
754
755out_error:
756 trace_xfs_refcount_find_left_extent_error(cur->bc_mp,
757 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
758 return error;
759}
760
761/*
762 * Find the right extent and the one before it (cright). This function
763 * assumes that we've already split any extents crossing agbno + aglen.
764 */
765STATIC int
766xfs_refcount_find_right_extents(
767 struct xfs_btree_cur *cur,
768 struct xfs_refcount_irec *right,
769 struct xfs_refcount_irec *cright,
770 enum xfs_refc_domain domain,
771 xfs_agblock_t agbno,
772 xfs_extlen_t aglen)
773{
774 struct xfs_refcount_irec tmp;
775 int error;
776 int found_rec;
777
778 right->rc_startblock = cright->rc_startblock = NULLAGBLOCK;
779 error = xfs_refcount_lookup_ge(cur, domain, agbno + aglen, &found_rec);
780 if (error)
781 goto out_error;
782 if (!found_rec)
783 return 0;
784
785 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
786 if (error)
787 goto out_error;
788 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
789 xfs_btree_mark_sick(cur);
790 error = -EFSCORRUPTED;
791 goto out_error;
792 }
793
794 if (tmp.rc_domain != domain)
795 return 0;
796 if (tmp.rc_startblock != agbno + aglen)
797 return 0;
798 /* We have a right extent; retrieve (or invent) the next left one */
799 *right = tmp;
800
801 error = xfs_btree_decrement(cur, 0, &found_rec);
802 if (error)
803 goto out_error;
804 if (found_rec) {
805 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
806 if (error)
807 goto out_error;
808 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
809 xfs_btree_mark_sick(cur);
810 error = -EFSCORRUPTED;
811 goto out_error;
812 }
813
814 if (tmp.rc_domain != domain)
815 goto not_found;
816
817 /* if tmp ends at the end of our range, just use that */
818 if (xfs_refc_next(&tmp) == agbno + aglen)
819 *cright = tmp;
820 else {
821 /*
822 * There's a gap in the refcntbt at the end of the
823 * range we're interested in (refcount == 1) so
824 * create the implied extent and pass it back.
825 * We assume here that the agbno/aglen range was
826 * passed in from a data fork extent mapping and
827 * therefore is allocated to exactly one owner.
828 */
829 cright->rc_startblock = max(agbno, xfs_refc_next(&tmp));
830 cright->rc_blockcount = right->rc_startblock -
831 cright->rc_startblock;
832 cright->rc_refcount = 1;
833 cright->rc_domain = domain;
834 }
835 } else {
836not_found:
837 /*
838 * No extents, so pretend that there's one covering the whole
839 * range.
840 */
841 cright->rc_startblock = agbno;
842 cright->rc_blockcount = aglen;
843 cright->rc_refcount = 1;
844 cright->rc_domain = domain;
845 }
846 trace_xfs_refcount_find_right_extent(cur->bc_mp, cur->bc_ag.pag->pag_agno,
847 cright, right, agbno + aglen);
848 return error;
849
850out_error:
851 trace_xfs_refcount_find_right_extent_error(cur->bc_mp,
852 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
853 return error;
854}
855
856/* Is this extent valid? */
857static inline bool
858xfs_refc_valid(
859 const struct xfs_refcount_irec *rc)
860{
861 return rc->rc_startblock != NULLAGBLOCK;
862}
863
864static inline xfs_nlink_t
865xfs_refc_merge_refcount(
866 const struct xfs_refcount_irec *irec,
867 enum xfs_refc_adjust_op adjust)
868{
869 /* Once a record hits MAXREFCOUNT, it is pinned there forever */
870 if (irec->rc_refcount == MAXREFCOUNT)
871 return MAXREFCOUNT;
872 return irec->rc_refcount + adjust;
873}
874
875static inline bool
876xfs_refc_want_merge_center(
877 const struct xfs_refcount_irec *left,
878 const struct xfs_refcount_irec *cleft,
879 const struct xfs_refcount_irec *cright,
880 const struct xfs_refcount_irec *right,
881 bool cleft_is_cright,
882 enum xfs_refc_adjust_op adjust,
883 unsigned long long *ulenp)
884{
885 unsigned long long ulen = left->rc_blockcount;
886 xfs_nlink_t new_refcount;
887
888 /*
889 * To merge with a center record, both shoulder records must be
890 * adjacent to the record we want to adjust. This is only true if
891 * find_left and find_right made all four records valid.
892 */
893 if (!xfs_refc_valid(left) || !xfs_refc_valid(right) ||
894 !xfs_refc_valid(cleft) || !xfs_refc_valid(cright))
895 return false;
896
897 /* There must only be one record for the entire range. */
898 if (!cleft_is_cright)
899 return false;
900
901 /* The shoulder record refcounts must match the new refcount. */
902 new_refcount = xfs_refc_merge_refcount(cleft, adjust);
903 if (left->rc_refcount != new_refcount)
904 return false;
905 if (right->rc_refcount != new_refcount)
906 return false;
907
908 /*
909 * The new record cannot exceed the max length. ulen is a ULL as the
910 * individual record block counts can be up to (u32 - 1) in length
911 * hence we need to catch u32 addition overflows here.
912 */
913 ulen += cleft->rc_blockcount + right->rc_blockcount;
914 if (ulen >= MAXREFCEXTLEN)
915 return false;
916
917 *ulenp = ulen;
918 return true;
919}
920
921static inline bool
922xfs_refc_want_merge_left(
923 const struct xfs_refcount_irec *left,
924 const struct xfs_refcount_irec *cleft,
925 enum xfs_refc_adjust_op adjust)
926{
927 unsigned long long ulen = left->rc_blockcount;
928 xfs_nlink_t new_refcount;
929
930 /*
931 * For a left merge, the left shoulder record must be adjacent to the
932 * start of the range. If this is true, find_left made left and cleft
933 * contain valid contents.
934 */
935 if (!xfs_refc_valid(left) || !xfs_refc_valid(cleft))
936 return false;
937
938 /* Left shoulder record refcount must match the new refcount. */
939 new_refcount = xfs_refc_merge_refcount(cleft, adjust);
940 if (left->rc_refcount != new_refcount)
941 return false;
942
943 /*
944 * The new record cannot exceed the max length. ulen is a ULL as the
945 * individual record block counts can be up to (u32 - 1) in length
946 * hence we need to catch u32 addition overflows here.
947 */
948 ulen += cleft->rc_blockcount;
949 if (ulen >= MAXREFCEXTLEN)
950 return false;
951
952 return true;
953}
954
955static inline bool
956xfs_refc_want_merge_right(
957 const struct xfs_refcount_irec *cright,
958 const struct xfs_refcount_irec *right,
959 enum xfs_refc_adjust_op adjust)
960{
961 unsigned long long ulen = right->rc_blockcount;
962 xfs_nlink_t new_refcount;
963
964 /*
965 * For a right merge, the right shoulder record must be adjacent to the
966 * end of the range. If this is true, find_right made cright and right
967 * contain valid contents.
968 */
969 if (!xfs_refc_valid(right) || !xfs_refc_valid(cright))
970 return false;
971
972 /* Right shoulder record refcount must match the new refcount. */
973 new_refcount = xfs_refc_merge_refcount(cright, adjust);
974 if (right->rc_refcount != new_refcount)
975 return false;
976
977 /*
978 * The new record cannot exceed the max length. ulen is a ULL as the
979 * individual record block counts can be up to (u32 - 1) in length
980 * hence we need to catch u32 addition overflows here.
981 */
982 ulen += cright->rc_blockcount;
983 if (ulen >= MAXREFCEXTLEN)
984 return false;
985
986 return true;
987}
988
989/*
990 * Try to merge with any extents on the boundaries of the adjustment range.
991 */
992STATIC int
993xfs_refcount_merge_extents(
994 struct xfs_btree_cur *cur,
995 enum xfs_refc_domain domain,
996 xfs_agblock_t *agbno,
997 xfs_extlen_t *aglen,
998 enum xfs_refc_adjust_op adjust,
999 bool *shape_changed)
1000{
1001 struct xfs_refcount_irec left = {0}, cleft = {0};
1002 struct xfs_refcount_irec cright = {0}, right = {0};
1003 int error;
1004 unsigned long long ulen;
1005 bool cequal;
1006
1007 *shape_changed = false;
1008 /*
1009 * Find the extent just below agbno [left], just above agbno [cleft],
1010 * just below (agbno + aglen) [cright], and just above (agbno + aglen)
1011 * [right].
1012 */
1013 error = xfs_refcount_find_left_extents(cur, &left, &cleft, domain,
1014 *agbno, *aglen);
1015 if (error)
1016 return error;
1017 error = xfs_refcount_find_right_extents(cur, &right, &cright, domain,
1018 *agbno, *aglen);
1019 if (error)
1020 return error;
1021
1022 /* No left or right extent to merge; exit. */
1023 if (!xfs_refc_valid(&left) && !xfs_refc_valid(&right))
1024 return 0;
1025
1026 cequal = (cleft.rc_startblock == cright.rc_startblock) &&
1027 (cleft.rc_blockcount == cright.rc_blockcount);
1028
1029 /* Try to merge left, cleft, and right. cleft must == cright. */
1030 if (xfs_refc_want_merge_center(&left, &cleft, &cright, &right, cequal,
1031 adjust, &ulen)) {
1032 *shape_changed = true;
1033 return xfs_refcount_merge_center_extents(cur, &left, &cleft,
1034 &right, ulen, aglen);
1035 }
1036
1037 /* Try to merge left and cleft. */
1038 if (xfs_refc_want_merge_left(&left, &cleft, adjust)) {
1039 *shape_changed = true;
1040 error = xfs_refcount_merge_left_extent(cur, &left, &cleft,
1041 agbno, aglen);
1042 if (error)
1043 return error;
1044
1045 /*
1046 * If we just merged left + cleft and cleft == cright,
1047 * we no longer have a cright to merge with right. We're done.
1048 */
1049 if (cequal)
1050 return 0;
1051 }
1052
1053 /* Try to merge cright and right. */
1054 if (xfs_refc_want_merge_right(&cright, &right, adjust)) {
1055 *shape_changed = true;
1056 return xfs_refcount_merge_right_extent(cur, &right, &cright,
1057 aglen);
1058 }
1059
1060 return 0;
1061}
1062
1063/*
1064 * XXX: This is a pretty hand-wavy estimate. The penalty for guessing
1065 * true incorrectly is a shutdown FS; the penalty for guessing false
1066 * incorrectly is more transaction rolls than might be necessary.
1067 * Be conservative here.
1068 */
1069static bool
1070xfs_refcount_still_have_space(
1071 struct xfs_btree_cur *cur)
1072{
1073 unsigned long overhead;
1074
1075 /*
1076 * Worst case estimate: full splits of the free space and rmap btrees
1077 * to handle each of the shape changes to the refcount btree.
1078 */
1079 overhead = xfs_allocfree_block_count(cur->bc_mp,
1080 cur->bc_refc.shape_changes);
1081 overhead += cur->bc_mp->m_refc_maxlevels;
1082 overhead *= cur->bc_mp->m_sb.sb_blocksize;
1083
1084 /*
1085 * Only allow 2 refcount extent updates per transaction if the
1086 * refcount continue update "error" has been injected.
1087 */
1088 if (cur->bc_refc.nr_ops > 2 &&
1089 XFS_TEST_ERROR(false, cur->bc_mp,
1090 XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE))
1091 return false;
1092
1093 if (cur->bc_refc.nr_ops == 0)
1094 return true;
1095 else if (overhead > cur->bc_tp->t_log_res)
1096 return false;
1097 return cur->bc_tp->t_log_res - overhead >
1098 cur->bc_refc.nr_ops * XFS_REFCOUNT_ITEM_OVERHEAD;
1099}
1100
1101/*
1102 * Adjust the refcounts of middle extents. At this point we should have
1103 * split extents that crossed the adjustment range; merged with adjacent
1104 * extents; and updated agbno/aglen to reflect the merges. Therefore,
1105 * all we have to do is update the extents inside [agbno, agbno + aglen].
1106 */
1107STATIC int
1108xfs_refcount_adjust_extents(
1109 struct xfs_btree_cur *cur,
1110 xfs_agblock_t *agbno,
1111 xfs_extlen_t *aglen,
1112 enum xfs_refc_adjust_op adj)
1113{
1114 struct xfs_refcount_irec ext, tmp;
1115 int error;
1116 int found_rec, found_tmp;
1117 xfs_fsblock_t fsbno;
1118
1119 /* Merging did all the work already. */
1120 if (*aglen == 0)
1121 return 0;
1122
1123 error = xfs_refcount_lookup_ge(cur, XFS_REFC_DOMAIN_SHARED, *agbno,
1124 &found_rec);
1125 if (error)
1126 goto out_error;
1127
1128 while (*aglen > 0 && xfs_refcount_still_have_space(cur)) {
1129 error = xfs_refcount_get_rec(cur, &ext, &found_rec);
1130 if (error)
1131 goto out_error;
1132 if (!found_rec || ext.rc_domain != XFS_REFC_DOMAIN_SHARED) {
1133 ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks;
1134 ext.rc_blockcount = 0;
1135 ext.rc_refcount = 0;
1136 ext.rc_domain = XFS_REFC_DOMAIN_SHARED;
1137 }
1138
1139 /*
1140 * Deal with a hole in the refcount tree; if a file maps to
1141 * these blocks and there's no refcountbt record, pretend that
1142 * there is one with refcount == 1.
1143 */
1144 if (ext.rc_startblock != *agbno) {
1145 tmp.rc_startblock = *agbno;
1146 tmp.rc_blockcount = min(*aglen,
1147 ext.rc_startblock - *agbno);
1148 tmp.rc_refcount = 1 + adj;
1149 tmp.rc_domain = XFS_REFC_DOMAIN_SHARED;
1150
1151 trace_xfs_refcount_modify_extent(cur->bc_mp,
1152 cur->bc_ag.pag->pag_agno, &tmp);
1153
1154 /*
1155 * Either cover the hole (increment) or
1156 * delete the range (decrement).
1157 */
1158 cur->bc_refc.nr_ops++;
1159 if (tmp.rc_refcount) {
1160 error = xfs_refcount_insert(cur, &tmp,
1161 &found_tmp);
1162 if (error)
1163 goto out_error;
1164 if (XFS_IS_CORRUPT(cur->bc_mp,
1165 found_tmp != 1)) {
1166 xfs_btree_mark_sick(cur);
1167 error = -EFSCORRUPTED;
1168 goto out_error;
1169 }
1170 } else {
1171 fsbno = XFS_AGB_TO_FSB(cur->bc_mp,
1172 cur->bc_ag.pag->pag_agno,
1173 tmp.rc_startblock);
1174 error = xfs_free_extent_later(cur->bc_tp, fsbno,
1175 tmp.rc_blockcount, NULL,
1176 XFS_AG_RESV_NONE, false);
1177 if (error)
1178 goto out_error;
1179 }
1180
1181 (*agbno) += tmp.rc_blockcount;
1182 (*aglen) -= tmp.rc_blockcount;
1183
1184 /* Stop if there's nothing left to modify */
1185 if (*aglen == 0 || !xfs_refcount_still_have_space(cur))
1186 break;
1187
1188 /* Move the cursor to the start of ext. */
1189 error = xfs_refcount_lookup_ge(cur,
1190 XFS_REFC_DOMAIN_SHARED, *agbno,
1191 &found_rec);
1192 if (error)
1193 goto out_error;
1194 }
1195
1196 /*
1197 * A previous step trimmed agbno/aglen such that the end of the
1198 * range would not be in the middle of the record. If this is
1199 * no longer the case, something is seriously wrong with the
1200 * btree. Make sure we never feed the synthesized record into
1201 * the processing loop below.
1202 */
1203 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount == 0) ||
1204 XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount > *aglen)) {
1205 xfs_btree_mark_sick(cur);
1206 error = -EFSCORRUPTED;
1207 goto out_error;
1208 }
1209
1210 /*
1211 * Adjust the reference count and either update the tree
1212 * (incr) or free the blocks (decr).
1213 */
1214 if (ext.rc_refcount == MAXREFCOUNT)
1215 goto skip;
1216 ext.rc_refcount += adj;
1217 trace_xfs_refcount_modify_extent(cur->bc_mp,
1218 cur->bc_ag.pag->pag_agno, &ext);
1219 cur->bc_refc.nr_ops++;
1220 if (ext.rc_refcount > 1) {
1221 error = xfs_refcount_update(cur, &ext);
1222 if (error)
1223 goto out_error;
1224 } else if (ext.rc_refcount == 1) {
1225 error = xfs_refcount_delete(cur, &found_rec);
1226 if (error)
1227 goto out_error;
1228 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
1229 xfs_btree_mark_sick(cur);
1230 error = -EFSCORRUPTED;
1231 goto out_error;
1232 }
1233 goto advloop;
1234 } else {
1235 fsbno = XFS_AGB_TO_FSB(cur->bc_mp,
1236 cur->bc_ag.pag->pag_agno,
1237 ext.rc_startblock);
1238 error = xfs_free_extent_later(cur->bc_tp, fsbno,
1239 ext.rc_blockcount, NULL,
1240 XFS_AG_RESV_NONE, false);
1241 if (error)
1242 goto out_error;
1243 }
1244
1245skip:
1246 error = xfs_btree_increment(cur, 0, &found_rec);
1247 if (error)
1248 goto out_error;
1249
1250advloop:
1251 (*agbno) += ext.rc_blockcount;
1252 (*aglen) -= ext.rc_blockcount;
1253 }
1254
1255 return error;
1256out_error:
1257 trace_xfs_refcount_modify_extent_error(cur->bc_mp,
1258 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
1259 return error;
1260}
1261
1262/* Adjust the reference count of a range of AG blocks. */
1263STATIC int
1264xfs_refcount_adjust(
1265 struct xfs_btree_cur *cur,
1266 xfs_agblock_t *agbno,
1267 xfs_extlen_t *aglen,
1268 enum xfs_refc_adjust_op adj)
1269{
1270 bool shape_changed;
1271 int shape_changes = 0;
1272 int error;
1273
1274 if (adj == XFS_REFCOUNT_ADJUST_INCREASE)
1275 trace_xfs_refcount_increase(cur->bc_mp,
1276 cur->bc_ag.pag->pag_agno, *agbno, *aglen);
1277 else
1278 trace_xfs_refcount_decrease(cur->bc_mp,
1279 cur->bc_ag.pag->pag_agno, *agbno, *aglen);
1280
1281 /*
1282 * Ensure that no rcextents cross the boundary of the adjustment range.
1283 */
1284 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_SHARED,
1285 *agbno, &shape_changed);
1286 if (error)
1287 goto out_error;
1288 if (shape_changed)
1289 shape_changes++;
1290
1291 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_SHARED,
1292 *agbno + *aglen, &shape_changed);
1293 if (error)
1294 goto out_error;
1295 if (shape_changed)
1296 shape_changes++;
1297
1298 /*
1299 * Try to merge with the left or right extents of the range.
1300 */
1301 error = xfs_refcount_merge_extents(cur, XFS_REFC_DOMAIN_SHARED,
1302 agbno, aglen, adj, &shape_changed);
1303 if (error)
1304 goto out_error;
1305 if (shape_changed)
1306 shape_changes++;
1307 if (shape_changes)
1308 cur->bc_refc.shape_changes++;
1309
1310 /* Now that we've taken care of the ends, adjust the middle extents */
1311 error = xfs_refcount_adjust_extents(cur, agbno, aglen, adj);
1312 if (error)
1313 goto out_error;
1314
1315 return 0;
1316
1317out_error:
1318 trace_xfs_refcount_adjust_error(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1319 error, _RET_IP_);
1320 return error;
1321}
1322
1323/* Clean up after calling xfs_refcount_finish_one. */
1324void
1325xfs_refcount_finish_one_cleanup(
1326 struct xfs_trans *tp,
1327 struct xfs_btree_cur *rcur,
1328 int error)
1329{
1330 struct xfs_buf *agbp;
1331
1332 if (rcur == NULL)
1333 return;
1334 agbp = rcur->bc_ag.agbp;
1335 xfs_btree_del_cursor(rcur, error);
1336 if (error)
1337 xfs_trans_brelse(tp, agbp);
1338}
1339
1340/*
1341 * Set up a continuation a deferred refcount operation by updating the intent.
1342 * Checks to make sure we're not going to run off the end of the AG.
1343 */
1344static inline int
1345xfs_refcount_continue_op(
1346 struct xfs_btree_cur *cur,
1347 struct xfs_refcount_intent *ri,
1348 xfs_agblock_t new_agbno)
1349{
1350 struct xfs_mount *mp = cur->bc_mp;
1351 struct xfs_perag *pag = cur->bc_ag.pag;
1352
1353 if (XFS_IS_CORRUPT(mp, !xfs_verify_agbext(pag, new_agbno,
1354 ri->ri_blockcount))) {
1355 xfs_btree_mark_sick(cur);
1356 return -EFSCORRUPTED;
1357 }
1358
1359 ri->ri_startblock = XFS_AGB_TO_FSB(mp, pag->pag_agno, new_agbno);
1360
1361 ASSERT(xfs_verify_fsbext(mp, ri->ri_startblock, ri->ri_blockcount));
1362 ASSERT(pag->pag_agno == XFS_FSB_TO_AGNO(mp, ri->ri_startblock));
1363
1364 return 0;
1365}
1366
1367/*
1368 * Process one of the deferred refcount operations. We pass back the
1369 * btree cursor to maintain our lock on the btree between calls.
1370 * This saves time and eliminates a buffer deadlock between the
1371 * superblock and the AGF because we'll always grab them in the same
1372 * order.
1373 */
1374int
1375xfs_refcount_finish_one(
1376 struct xfs_trans *tp,
1377 struct xfs_refcount_intent *ri,
1378 struct xfs_btree_cur **pcur)
1379{
1380 struct xfs_mount *mp = tp->t_mountp;
1381 struct xfs_btree_cur *rcur;
1382 struct xfs_buf *agbp = NULL;
1383 int error = 0;
1384 xfs_agblock_t bno;
1385 unsigned long nr_ops = 0;
1386 int shape_changes = 0;
1387
1388 bno = XFS_FSB_TO_AGBNO(mp, ri->ri_startblock);
1389
1390 trace_xfs_refcount_deferred(mp, XFS_FSB_TO_AGNO(mp, ri->ri_startblock),
1391 ri->ri_type, XFS_FSB_TO_AGBNO(mp, ri->ri_startblock),
1392 ri->ri_blockcount);
1393
1394 if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_REFCOUNT_FINISH_ONE))
1395 return -EIO;
1396
1397 /*
1398 * If we haven't gotten a cursor or the cursor AG doesn't match
1399 * the startblock, get one now.
1400 */
1401 rcur = *pcur;
1402 if (rcur != NULL && rcur->bc_ag.pag != ri->ri_pag) {
1403 nr_ops = rcur->bc_refc.nr_ops;
1404 shape_changes = rcur->bc_refc.shape_changes;
1405 xfs_refcount_finish_one_cleanup(tp, rcur, 0);
1406 rcur = NULL;
1407 *pcur = NULL;
1408 }
1409 if (rcur == NULL) {
1410 error = xfs_alloc_read_agf(ri->ri_pag, tp,
1411 XFS_ALLOC_FLAG_FREEING, &agbp);
1412 if (error)
1413 return error;
1414
1415 rcur = xfs_refcountbt_init_cursor(mp, tp, agbp, ri->ri_pag);
1416 rcur->bc_refc.nr_ops = nr_ops;
1417 rcur->bc_refc.shape_changes = shape_changes;
1418 }
1419 *pcur = rcur;
1420
1421 switch (ri->ri_type) {
1422 case XFS_REFCOUNT_INCREASE:
1423 error = xfs_refcount_adjust(rcur, &bno, &ri->ri_blockcount,
1424 XFS_REFCOUNT_ADJUST_INCREASE);
1425 if (error)
1426 return error;
1427 if (ri->ri_blockcount > 0)
1428 error = xfs_refcount_continue_op(rcur, ri, bno);
1429 break;
1430 case XFS_REFCOUNT_DECREASE:
1431 error = xfs_refcount_adjust(rcur, &bno, &ri->ri_blockcount,
1432 XFS_REFCOUNT_ADJUST_DECREASE);
1433 if (error)
1434 return error;
1435 if (ri->ri_blockcount > 0)
1436 error = xfs_refcount_continue_op(rcur, ri, bno);
1437 break;
1438 case XFS_REFCOUNT_ALLOC_COW:
1439 error = __xfs_refcount_cow_alloc(rcur, bno, ri->ri_blockcount);
1440 if (error)
1441 return error;
1442 ri->ri_blockcount = 0;
1443 break;
1444 case XFS_REFCOUNT_FREE_COW:
1445 error = __xfs_refcount_cow_free(rcur, bno, ri->ri_blockcount);
1446 if (error)
1447 return error;
1448 ri->ri_blockcount = 0;
1449 break;
1450 default:
1451 ASSERT(0);
1452 return -EFSCORRUPTED;
1453 }
1454 if (!error && ri->ri_blockcount > 0)
1455 trace_xfs_refcount_finish_one_leftover(mp, ri->ri_pag->pag_agno,
1456 ri->ri_type, bno, ri->ri_blockcount);
1457 return error;
1458}
1459
1460/*
1461 * Record a refcount intent for later processing.
1462 */
1463static void
1464__xfs_refcount_add(
1465 struct xfs_trans *tp,
1466 enum xfs_refcount_intent_type type,
1467 xfs_fsblock_t startblock,
1468 xfs_extlen_t blockcount)
1469{
1470 struct xfs_refcount_intent *ri;
1471
1472 trace_xfs_refcount_defer(tp->t_mountp,
1473 XFS_FSB_TO_AGNO(tp->t_mountp, startblock),
1474 type, XFS_FSB_TO_AGBNO(tp->t_mountp, startblock),
1475 blockcount);
1476
1477 ri = kmem_cache_alloc(xfs_refcount_intent_cache,
1478 GFP_KERNEL | __GFP_NOFAIL);
1479 INIT_LIST_HEAD(&ri->ri_list);
1480 ri->ri_type = type;
1481 ri->ri_startblock = startblock;
1482 ri->ri_blockcount = blockcount;
1483
1484 xfs_refcount_update_get_group(tp->t_mountp, ri);
1485 xfs_defer_add(tp, &ri->ri_list, &xfs_refcount_update_defer_type);
1486}
1487
1488/*
1489 * Increase the reference count of the blocks backing a file's extent.
1490 */
1491void
1492xfs_refcount_increase_extent(
1493 struct xfs_trans *tp,
1494 struct xfs_bmbt_irec *PREV)
1495{
1496 if (!xfs_has_reflink(tp->t_mountp))
1497 return;
1498
1499 __xfs_refcount_add(tp, XFS_REFCOUNT_INCREASE, PREV->br_startblock,
1500 PREV->br_blockcount);
1501}
1502
1503/*
1504 * Decrease the reference count of the blocks backing a file's extent.
1505 */
1506void
1507xfs_refcount_decrease_extent(
1508 struct xfs_trans *tp,
1509 struct xfs_bmbt_irec *PREV)
1510{
1511 if (!xfs_has_reflink(tp->t_mountp))
1512 return;
1513
1514 __xfs_refcount_add(tp, XFS_REFCOUNT_DECREASE, PREV->br_startblock,
1515 PREV->br_blockcount);
1516}
1517
1518/*
1519 * Given an AG extent, find the lowest-numbered run of shared blocks
1520 * within that range and return the range in fbno/flen. If
1521 * find_end_of_shared is set, return the longest contiguous extent of
1522 * shared blocks; if not, just return the first extent we find. If no
1523 * shared blocks are found, fbno and flen will be set to NULLAGBLOCK
1524 * and 0, respectively.
1525 */
1526int
1527xfs_refcount_find_shared(
1528 struct xfs_btree_cur *cur,
1529 xfs_agblock_t agbno,
1530 xfs_extlen_t aglen,
1531 xfs_agblock_t *fbno,
1532 xfs_extlen_t *flen,
1533 bool find_end_of_shared)
1534{
1535 struct xfs_refcount_irec tmp;
1536 int i;
1537 int have;
1538 int error;
1539
1540 trace_xfs_refcount_find_shared(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1541 agbno, aglen);
1542
1543 /* By default, skip the whole range */
1544 *fbno = NULLAGBLOCK;
1545 *flen = 0;
1546
1547 /* Try to find a refcount extent that crosses the start */
1548 error = xfs_refcount_lookup_le(cur, XFS_REFC_DOMAIN_SHARED, agbno,
1549 &have);
1550 if (error)
1551 goto out_error;
1552 if (!have) {
1553 /* No left extent, look at the next one */
1554 error = xfs_btree_increment(cur, 0, &have);
1555 if (error)
1556 goto out_error;
1557 if (!have)
1558 goto done;
1559 }
1560 error = xfs_refcount_get_rec(cur, &tmp, &i);
1561 if (error)
1562 goto out_error;
1563 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
1564 xfs_btree_mark_sick(cur);
1565 error = -EFSCORRUPTED;
1566 goto out_error;
1567 }
1568 if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED)
1569 goto done;
1570
1571 /* If the extent ends before the start, look at the next one */
1572 if (tmp.rc_startblock + tmp.rc_blockcount <= agbno) {
1573 error = xfs_btree_increment(cur, 0, &have);
1574 if (error)
1575 goto out_error;
1576 if (!have)
1577 goto done;
1578 error = xfs_refcount_get_rec(cur, &tmp, &i);
1579 if (error)
1580 goto out_error;
1581 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
1582 xfs_btree_mark_sick(cur);
1583 error = -EFSCORRUPTED;
1584 goto out_error;
1585 }
1586 if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED)
1587 goto done;
1588 }
1589
1590 /* If the extent starts after the range we want, bail out */
1591 if (tmp.rc_startblock >= agbno + aglen)
1592 goto done;
1593
1594 /* We found the start of a shared extent! */
1595 if (tmp.rc_startblock < agbno) {
1596 tmp.rc_blockcount -= (agbno - tmp.rc_startblock);
1597 tmp.rc_startblock = agbno;
1598 }
1599
1600 *fbno = tmp.rc_startblock;
1601 *flen = min(tmp.rc_blockcount, agbno + aglen - *fbno);
1602 if (!find_end_of_shared)
1603 goto done;
1604
1605 /* Otherwise, find the end of this shared extent */
1606 while (*fbno + *flen < agbno + aglen) {
1607 error = xfs_btree_increment(cur, 0, &have);
1608 if (error)
1609 goto out_error;
1610 if (!have)
1611 break;
1612 error = xfs_refcount_get_rec(cur, &tmp, &i);
1613 if (error)
1614 goto out_error;
1615 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
1616 xfs_btree_mark_sick(cur);
1617 error = -EFSCORRUPTED;
1618 goto out_error;
1619 }
1620 if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED ||
1621 tmp.rc_startblock >= agbno + aglen ||
1622 tmp.rc_startblock != *fbno + *flen)
1623 break;
1624 *flen = min(*flen + tmp.rc_blockcount, agbno + aglen - *fbno);
1625 }
1626
1627done:
1628 trace_xfs_refcount_find_shared_result(cur->bc_mp,
1629 cur->bc_ag.pag->pag_agno, *fbno, *flen);
1630
1631out_error:
1632 if (error)
1633 trace_xfs_refcount_find_shared_error(cur->bc_mp,
1634 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
1635 return error;
1636}
1637
1638/*
1639 * Recovering CoW Blocks After a Crash
1640 *
1641 * Due to the way that the copy on write mechanism works, there's a window of
1642 * opportunity in which we can lose track of allocated blocks during a crash.
1643 * Because CoW uses delayed allocation in the in-core CoW fork, writeback
1644 * causes blocks to be allocated and stored in the CoW fork. The blocks are
1645 * no longer in the free space btree but are not otherwise recorded anywhere
1646 * until the write completes and the blocks are mapped into the file. A crash
1647 * in between allocation and remapping results in the replacement blocks being
1648 * lost. This situation is exacerbated by the CoW extent size hint because
1649 * allocations can hang around for long time.
1650 *
1651 * However, there is a place where we can record these allocations before they
1652 * become mappings -- the reference count btree. The btree does not record
1653 * extents with refcount == 1, so we can record allocations with a refcount of
1654 * 1. Blocks being used for CoW writeout cannot be shared, so there should be
1655 * no conflict with shared block records. These mappings should be created
1656 * when we allocate blocks to the CoW fork and deleted when they're removed
1657 * from the CoW fork.
1658 *
1659 * Minor nit: records for in-progress CoW allocations and records for shared
1660 * extents must never be merged, to preserve the property that (except for CoW
1661 * allocations) there are no refcount btree entries with refcount == 1. The
1662 * only time this could potentially happen is when unsharing a block that's
1663 * adjacent to CoW allocations, so we must be careful to avoid this.
1664 *
1665 * At mount time we recover lost CoW allocations by searching the refcount
1666 * btree for these refcount == 1 mappings. These represent CoW allocations
1667 * that were in progress at the time the filesystem went down, so we can free
1668 * them to get the space back.
1669 *
1670 * This mechanism is superior to creating EFIs for unmapped CoW extents for
1671 * several reasons -- first, EFIs pin the tail of the log and would have to be
1672 * periodically relogged to avoid filling up the log. Second, CoW completions
1673 * will have to file an EFD and create new EFIs for whatever remains in the
1674 * CoW fork; this partially takes care of (1) but extent-size reservations
1675 * will have to periodically relog even if there's no writeout in progress.
1676 * This can happen if the CoW extent size hint is set, which you really want.
1677 * Third, EFIs cannot currently be automatically relogged into newer
1678 * transactions to advance the log tail. Fourth, stuffing the log full of
1679 * EFIs places an upper bound on the number of CoW allocations that can be
1680 * held filesystem-wide at any given time. Recording them in the refcount
1681 * btree doesn't require us to maintain any state in memory and doesn't pin
1682 * the log.
1683 */
1684/*
1685 * Adjust the refcounts of CoW allocations. These allocations are "magic"
1686 * in that they're not referenced anywhere else in the filesystem, so we
1687 * stash them in the refcount btree with a refcount of 1 until either file
1688 * remapping (or CoW cancellation) happens.
1689 */
1690STATIC int
1691xfs_refcount_adjust_cow_extents(
1692 struct xfs_btree_cur *cur,
1693 xfs_agblock_t agbno,
1694 xfs_extlen_t aglen,
1695 enum xfs_refc_adjust_op adj)
1696{
1697 struct xfs_refcount_irec ext, tmp;
1698 int error;
1699 int found_rec, found_tmp;
1700
1701 if (aglen == 0)
1702 return 0;
1703
1704 /* Find any overlapping refcount records */
1705 error = xfs_refcount_lookup_ge(cur, XFS_REFC_DOMAIN_COW, agbno,
1706 &found_rec);
1707 if (error)
1708 goto out_error;
1709 error = xfs_refcount_get_rec(cur, &ext, &found_rec);
1710 if (error)
1711 goto out_error;
1712 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec &&
1713 ext.rc_domain != XFS_REFC_DOMAIN_COW)) {
1714 xfs_btree_mark_sick(cur);
1715 error = -EFSCORRUPTED;
1716 goto out_error;
1717 }
1718 if (!found_rec) {
1719 ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks;
1720 ext.rc_blockcount = 0;
1721 ext.rc_refcount = 0;
1722 ext.rc_domain = XFS_REFC_DOMAIN_COW;
1723 }
1724
1725 switch (adj) {
1726 case XFS_REFCOUNT_ADJUST_COW_ALLOC:
1727 /* Adding a CoW reservation, there should be nothing here. */
1728 if (XFS_IS_CORRUPT(cur->bc_mp,
1729 agbno + aglen > ext.rc_startblock)) {
1730 xfs_btree_mark_sick(cur);
1731 error = -EFSCORRUPTED;
1732 goto out_error;
1733 }
1734
1735 tmp.rc_startblock = agbno;
1736 tmp.rc_blockcount = aglen;
1737 tmp.rc_refcount = 1;
1738 tmp.rc_domain = XFS_REFC_DOMAIN_COW;
1739
1740 trace_xfs_refcount_modify_extent(cur->bc_mp,
1741 cur->bc_ag.pag->pag_agno, &tmp);
1742
1743 error = xfs_refcount_insert(cur, &tmp,
1744 &found_tmp);
1745 if (error)
1746 goto out_error;
1747 if (XFS_IS_CORRUPT(cur->bc_mp, found_tmp != 1)) {
1748 xfs_btree_mark_sick(cur);
1749 error = -EFSCORRUPTED;
1750 goto out_error;
1751 }
1752 break;
1753 case XFS_REFCOUNT_ADJUST_COW_FREE:
1754 /* Removing a CoW reservation, there should be one extent. */
1755 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_startblock != agbno)) {
1756 xfs_btree_mark_sick(cur);
1757 error = -EFSCORRUPTED;
1758 goto out_error;
1759 }
1760 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount != aglen)) {
1761 xfs_btree_mark_sick(cur);
1762 error = -EFSCORRUPTED;
1763 goto out_error;
1764 }
1765 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_refcount != 1)) {
1766 xfs_btree_mark_sick(cur);
1767 error = -EFSCORRUPTED;
1768 goto out_error;
1769 }
1770
1771 ext.rc_refcount = 0;
1772 trace_xfs_refcount_modify_extent(cur->bc_mp,
1773 cur->bc_ag.pag->pag_agno, &ext);
1774 error = xfs_refcount_delete(cur, &found_rec);
1775 if (error)
1776 goto out_error;
1777 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {
1778 xfs_btree_mark_sick(cur);
1779 error = -EFSCORRUPTED;
1780 goto out_error;
1781 }
1782 break;
1783 default:
1784 ASSERT(0);
1785 }
1786
1787 return error;
1788out_error:
1789 trace_xfs_refcount_modify_extent_error(cur->bc_mp,
1790 cur->bc_ag.pag->pag_agno, error, _RET_IP_);
1791 return error;
1792}
1793
1794/*
1795 * Add or remove refcount btree entries for CoW reservations.
1796 */
1797STATIC int
1798xfs_refcount_adjust_cow(
1799 struct xfs_btree_cur *cur,
1800 xfs_agblock_t agbno,
1801 xfs_extlen_t aglen,
1802 enum xfs_refc_adjust_op adj)
1803{
1804 bool shape_changed;
1805 int error;
1806
1807 /*
1808 * Ensure that no rcextents cross the boundary of the adjustment range.
1809 */
1810 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_COW,
1811 agbno, &shape_changed);
1812 if (error)
1813 goto out_error;
1814
1815 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_COW,
1816 agbno + aglen, &shape_changed);
1817 if (error)
1818 goto out_error;
1819
1820 /*
1821 * Try to merge with the left or right extents of the range.
1822 */
1823 error = xfs_refcount_merge_extents(cur, XFS_REFC_DOMAIN_COW, &agbno,
1824 &aglen, adj, &shape_changed);
1825 if (error)
1826 goto out_error;
1827
1828 /* Now that we've taken care of the ends, adjust the middle extents */
1829 error = xfs_refcount_adjust_cow_extents(cur, agbno, aglen, adj);
1830 if (error)
1831 goto out_error;
1832
1833 return 0;
1834
1835out_error:
1836 trace_xfs_refcount_adjust_cow_error(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1837 error, _RET_IP_);
1838 return error;
1839}
1840
1841/*
1842 * Record a CoW allocation in the refcount btree.
1843 */
1844STATIC int
1845__xfs_refcount_cow_alloc(
1846 struct xfs_btree_cur *rcur,
1847 xfs_agblock_t agbno,
1848 xfs_extlen_t aglen)
1849{
1850 trace_xfs_refcount_cow_increase(rcur->bc_mp, rcur->bc_ag.pag->pag_agno,
1851 agbno, aglen);
1852
1853 /* Add refcount btree reservation */
1854 return xfs_refcount_adjust_cow(rcur, agbno, aglen,
1855 XFS_REFCOUNT_ADJUST_COW_ALLOC);
1856}
1857
1858/*
1859 * Remove a CoW allocation from the refcount btree.
1860 */
1861STATIC int
1862__xfs_refcount_cow_free(
1863 struct xfs_btree_cur *rcur,
1864 xfs_agblock_t agbno,
1865 xfs_extlen_t aglen)
1866{
1867 trace_xfs_refcount_cow_decrease(rcur->bc_mp, rcur->bc_ag.pag->pag_agno,
1868 agbno, aglen);
1869
1870 /* Remove refcount btree reservation */
1871 return xfs_refcount_adjust_cow(rcur, agbno, aglen,
1872 XFS_REFCOUNT_ADJUST_COW_FREE);
1873}
1874
1875/* Record a CoW staging extent in the refcount btree. */
1876void
1877xfs_refcount_alloc_cow_extent(
1878 struct xfs_trans *tp,
1879 xfs_fsblock_t fsb,
1880 xfs_extlen_t len)
1881{
1882 struct xfs_mount *mp = tp->t_mountp;
1883
1884 if (!xfs_has_reflink(mp))
1885 return;
1886
1887 __xfs_refcount_add(tp, XFS_REFCOUNT_ALLOC_COW, fsb, len);
1888
1889 /* Add rmap entry */
1890 xfs_rmap_alloc_extent(tp, XFS_FSB_TO_AGNO(mp, fsb),
1891 XFS_FSB_TO_AGBNO(mp, fsb), len, XFS_RMAP_OWN_COW);
1892}
1893
1894/* Forget a CoW staging event in the refcount btree. */
1895void
1896xfs_refcount_free_cow_extent(
1897 struct xfs_trans *tp,
1898 xfs_fsblock_t fsb,
1899 xfs_extlen_t len)
1900{
1901 struct xfs_mount *mp = tp->t_mountp;
1902
1903 if (!xfs_has_reflink(mp))
1904 return;
1905
1906 /* Remove rmap entry */
1907 xfs_rmap_free_extent(tp, XFS_FSB_TO_AGNO(mp, fsb),
1908 XFS_FSB_TO_AGBNO(mp, fsb), len, XFS_RMAP_OWN_COW);
1909 __xfs_refcount_add(tp, XFS_REFCOUNT_FREE_COW, fsb, len);
1910}
1911
1912struct xfs_refcount_recovery {
1913 struct list_head rr_list;
1914 struct xfs_refcount_irec rr_rrec;
1915};
1916
1917/* Stuff an extent on the recovery list. */
1918STATIC int
1919xfs_refcount_recover_extent(
1920 struct xfs_btree_cur *cur,
1921 const union xfs_btree_rec *rec,
1922 void *priv)
1923{
1924 struct list_head *debris = priv;
1925 struct xfs_refcount_recovery *rr;
1926
1927 if (XFS_IS_CORRUPT(cur->bc_mp,
1928 be32_to_cpu(rec->refc.rc_refcount) != 1)) {
1929 xfs_btree_mark_sick(cur);
1930 return -EFSCORRUPTED;
1931 }
1932
1933 rr = kmalloc(sizeof(struct xfs_refcount_recovery),
1934 GFP_KERNEL | __GFP_NOFAIL);
1935 INIT_LIST_HEAD(&rr->rr_list);
1936 xfs_refcount_btrec_to_irec(rec, &rr->rr_rrec);
1937
1938 if (xfs_refcount_check_irec(cur->bc_ag.pag, &rr->rr_rrec) != NULL ||
1939 XFS_IS_CORRUPT(cur->bc_mp,
1940 rr->rr_rrec.rc_domain != XFS_REFC_DOMAIN_COW)) {
1941 xfs_btree_mark_sick(cur);
1942 kfree(rr);
1943 return -EFSCORRUPTED;
1944 }
1945
1946 list_add_tail(&rr->rr_list, debris);
1947 return 0;
1948}
1949
1950/* Find and remove leftover CoW reservations. */
1951int
1952xfs_refcount_recover_cow_leftovers(
1953 struct xfs_mount *mp,
1954 struct xfs_perag *pag)
1955{
1956 struct xfs_trans *tp;
1957 struct xfs_btree_cur *cur;
1958 struct xfs_buf *agbp;
1959 struct xfs_refcount_recovery *rr, *n;
1960 struct list_head debris;
1961 union xfs_btree_irec low = {
1962 .rc.rc_domain = XFS_REFC_DOMAIN_COW,
1963 };
1964 union xfs_btree_irec high = {
1965 .rc.rc_domain = XFS_REFC_DOMAIN_COW,
1966 .rc.rc_startblock = -1U,
1967 };
1968 xfs_fsblock_t fsb;
1969 int error;
1970
1971 /* reflink filesystems mustn't have AGs larger than 2^31-1 blocks */
1972 BUILD_BUG_ON(XFS_MAX_CRC_AG_BLOCKS >= XFS_REFC_COWFLAG);
1973 if (mp->m_sb.sb_agblocks > XFS_MAX_CRC_AG_BLOCKS)
1974 return -EOPNOTSUPP;
1975
1976 INIT_LIST_HEAD(&debris);
1977
1978 /*
1979 * In this first part, we use an empty transaction to gather up
1980 * all the leftover CoW extents so that we can subsequently
1981 * delete them. The empty transaction is used to avoid
1982 * a buffer lock deadlock if there happens to be a loop in the
1983 * refcountbt because we're allowed to re-grab a buffer that is
1984 * already attached to our transaction. When we're done
1985 * recording the CoW debris we cancel the (empty) transaction
1986 * and everything goes away cleanly.
1987 */
1988 error = xfs_trans_alloc_empty(mp, &tp);
1989 if (error)
1990 return error;
1991
1992 error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
1993 if (error)
1994 goto out_trans;
1995 cur = xfs_refcountbt_init_cursor(mp, tp, agbp, pag);
1996
1997 /* Find all the leftover CoW staging extents. */
1998 error = xfs_btree_query_range(cur, &low, &high,
1999 xfs_refcount_recover_extent, &debris);
2000 xfs_btree_del_cursor(cur, error);
2001 xfs_trans_brelse(tp, agbp);
2002 xfs_trans_cancel(tp);
2003 if (error)
2004 goto out_free;
2005
2006 /* Now iterate the list to free the leftovers */
2007 list_for_each_entry_safe(rr, n, &debris, rr_list) {
2008 /* Set up transaction. */
2009 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
2010 if (error)
2011 goto out_free;
2012
2013 trace_xfs_refcount_recover_extent(mp, pag->pag_agno,
2014 &rr->rr_rrec);
2015
2016 /* Free the orphan record */
2017 fsb = XFS_AGB_TO_FSB(mp, pag->pag_agno,
2018 rr->rr_rrec.rc_startblock);
2019 xfs_refcount_free_cow_extent(tp, fsb,
2020 rr->rr_rrec.rc_blockcount);
2021
2022 /* Free the block. */
2023 error = xfs_free_extent_later(tp, fsb,
2024 rr->rr_rrec.rc_blockcount, NULL,
2025 XFS_AG_RESV_NONE, false);
2026 if (error)
2027 goto out_trans;
2028
2029 error = xfs_trans_commit(tp);
2030 if (error)
2031 goto out_free;
2032
2033 list_del(&rr->rr_list);
2034 kfree(rr);
2035 }
2036
2037 return error;
2038out_trans:
2039 xfs_trans_cancel(tp);
2040out_free:
2041 /* Free the leftover list */
2042 list_for_each_entry_safe(rr, n, &debris, rr_list) {
2043 list_del(&rr->rr_list);
2044 kfree(rr);
2045 }
2046 return error;
2047}
2048
2049/*
2050 * Scan part of the keyspace of the refcount records and tell us if the area
2051 * has no records, is fully mapped by records, or is partially filled.
2052 */
2053int
2054xfs_refcount_has_records(
2055 struct xfs_btree_cur *cur,
2056 enum xfs_refc_domain domain,
2057 xfs_agblock_t bno,
2058 xfs_extlen_t len,
2059 enum xbtree_recpacking *outcome)
2060{
2061 union xfs_btree_irec low;
2062 union xfs_btree_irec high;
2063
2064 memset(&low, 0, sizeof(low));
2065 low.rc.rc_startblock = bno;
2066 memset(&high, 0xFF, sizeof(high));
2067 high.rc.rc_startblock = bno + len - 1;
2068 low.rc.rc_domain = high.rc.rc_domain = domain;
2069
2070 return xfs_btree_has_records(cur, &low, &high, NULL, outcome);
2071}
2072
2073struct xfs_refcount_query_range_info {
2074 xfs_refcount_query_range_fn fn;
2075 void *priv;
2076};
2077
2078/* Format btree record and pass to our callback. */
2079STATIC int
2080xfs_refcount_query_range_helper(
2081 struct xfs_btree_cur *cur,
2082 const union xfs_btree_rec *rec,
2083 void *priv)
2084{
2085 struct xfs_refcount_query_range_info *query = priv;
2086 struct xfs_refcount_irec irec;
2087 xfs_failaddr_t fa;
2088
2089 xfs_refcount_btrec_to_irec(rec, &irec);
2090 fa = xfs_refcount_check_irec(cur->bc_ag.pag, &irec);
2091 if (fa)
2092 return xfs_refcount_complain_bad_rec(cur, fa, &irec);
2093
2094 return query->fn(cur, &irec, query->priv);
2095}
2096
2097/* Find all refcount records between two keys. */
2098int
2099xfs_refcount_query_range(
2100 struct xfs_btree_cur *cur,
2101 const struct xfs_refcount_irec *low_rec,
2102 const struct xfs_refcount_irec *high_rec,
2103 xfs_refcount_query_range_fn fn,
2104 void *priv)
2105{
2106 union xfs_btree_irec low_brec = { .rc = *low_rec };
2107 union xfs_btree_irec high_brec = { .rc = *high_rec };
2108 struct xfs_refcount_query_range_info query = { .priv = priv, .fn = fn };
2109
2110 return xfs_btree_query_range(cur, &low_brec, &high_brec,
2111 xfs_refcount_query_range_helper, &query);
2112}
2113
2114int __init
2115xfs_refcount_intent_init_cache(void)
2116{
2117 xfs_refcount_intent_cache = kmem_cache_create("xfs_refc_intent",
2118 sizeof(struct xfs_refcount_intent),
2119 0, 0, NULL);
2120
2121 return xfs_refcount_intent_cache != NULL ? 0 : -ENOMEM;
2122}
2123
2124void
2125xfs_refcount_intent_destroy_cache(void)
2126{
2127 kmem_cache_destroy(xfs_refcount_intent_cache);
2128 xfs_refcount_intent_cache = NULL;
2129}