2 * Copyright (C) 2016 Oracle. All Rights Reserved.
4 * Author: Darrick J. Wong <darrick.wong@oracle.com>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version 2
9 * of the License, or (at your option) any later version.
11 * This program is distributed in the hope that it would be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
22 #include "xfs_shared.h"
23 #include "xfs_format.h"
24 #include "xfs_log_format.h"
25 #include "xfs_trans_resv.h"
27 #include "xfs_mount.h"
28 #include "xfs_defer.h"
29 #include "xfs_btree.h"
31 #include "xfs_refcount_btree.h"
32 #include "xfs_alloc.h"
33 #include "xfs_error.h"
34 #include "xfs_trace.h"
35 #include "xfs_cksum.h"
36 #include "xfs_trans.h"
38 #include "xfs_refcount.h"
41 /* Allowable refcount adjustment amounts. */
42 enum xfs_refc_adjust_op {
43 XFS_REFCOUNT_ADJUST_INCREASE = 1,
44 XFS_REFCOUNT_ADJUST_DECREASE = -1,
45 XFS_REFCOUNT_ADJUST_COW_ALLOC = 0,
46 XFS_REFCOUNT_ADJUST_COW_FREE = -1,
49 STATIC int __xfs_refcount_cow_alloc(struct xfs_btree_cur *rcur,
50 xfs_agblock_t agbno, xfs_extlen_t aglen,
51 struct xfs_defer_ops *dfops);
52 STATIC int __xfs_refcount_cow_free(struct xfs_btree_cur *rcur,
53 xfs_agblock_t agbno, xfs_extlen_t aglen,
54 struct xfs_defer_ops *dfops);
57 * Look up the first record less than or equal to [bno, len] in the btree
61 xfs_refcount_lookup_le(
62 struct xfs_btree_cur *cur,
66 trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_private.a.agno, bno,
68 cur->bc_rec.rc.rc_startblock = bno;
69 cur->bc_rec.rc.rc_blockcount = 0;
70 return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
74 * Look up the first record greater than or equal to [bno, len] in the btree
78 xfs_refcount_lookup_ge(
79 struct xfs_btree_cur *cur,
83 trace_xfs_refcount_lookup(cur->bc_mp, cur->bc_private.a.agno, bno,
85 cur->bc_rec.rc.rc_startblock = bno;
86 cur->bc_rec.rc.rc_blockcount = 0;
87 return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
90 /* Convert on-disk record to in-core format. */
92 xfs_refcount_btrec_to_irec(
93 union xfs_btree_rec *rec,
94 struct xfs_refcount_irec *irec)
96 irec->rc_startblock = be32_to_cpu(rec->refc.rc_startblock);
97 irec->rc_blockcount = be32_to_cpu(rec->refc.rc_blockcount);
98 irec->rc_refcount = be32_to_cpu(rec->refc.rc_refcount);
102 * Get the data from the pointed-to record.
105 xfs_refcount_get_rec(
106 struct xfs_btree_cur *cur,
107 struct xfs_refcount_irec *irec,
110 union xfs_btree_rec *rec;
113 error = xfs_btree_get_rec(cur, &rec, stat);
114 if (!error && *stat == 1) {
115 xfs_refcount_btrec_to_irec(rec, irec);
116 trace_xfs_refcount_get(cur->bc_mp, cur->bc_private.a.agno,
123 * Update the record referred to by cur to the value given
124 * by [bno, len, refcount].
125 * This either works (return 0) or gets an EFSCORRUPTED error.
129 struct xfs_btree_cur *cur,
130 struct xfs_refcount_irec *irec)
132 union xfs_btree_rec rec;
135 trace_xfs_refcount_update(cur->bc_mp, cur->bc_private.a.agno, irec);
136 rec.refc.rc_startblock = cpu_to_be32(irec->rc_startblock);
137 rec.refc.rc_blockcount = cpu_to_be32(irec->rc_blockcount);
138 rec.refc.rc_refcount = cpu_to_be32(irec->rc_refcount);
139 error = xfs_btree_update(cur, &rec);
141 trace_xfs_refcount_update_error(cur->bc_mp,
142 cur->bc_private.a.agno, error, _RET_IP_);
147 * Insert the record referred to by cur to the value given
148 * by [bno, len, refcount].
149 * This either works (return 0) or gets an EFSCORRUPTED error.
153 struct xfs_btree_cur *cur,
154 struct xfs_refcount_irec *irec,
159 trace_xfs_refcount_insert(cur->bc_mp, cur->bc_private.a.agno, irec);
160 cur->bc_rec.rc.rc_startblock = irec->rc_startblock;
161 cur->bc_rec.rc.rc_blockcount = irec->rc_blockcount;
162 cur->bc_rec.rc.rc_refcount = irec->rc_refcount;
163 error = xfs_btree_insert(cur, i);
164 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, *i == 1, out_error);
167 trace_xfs_refcount_insert_error(cur->bc_mp,
168 cur->bc_private.a.agno, error, _RET_IP_);
173 * Remove the record referred to by cur, then set the pointer to the spot
174 * where the record could be re-inserted, in case we want to increment or
175 * decrement the cursor.
176 * This either works (return 0) or gets an EFSCORRUPTED error.
180 struct xfs_btree_cur *cur,
183 struct xfs_refcount_irec irec;
187 error = xfs_refcount_get_rec(cur, &irec, &found_rec);
190 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
191 trace_xfs_refcount_delete(cur->bc_mp, cur->bc_private.a.agno, &irec);
192 error = xfs_btree_delete(cur, i);
193 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, *i == 1, out_error);
196 error = xfs_refcount_lookup_ge(cur, irec.rc_startblock, &found_rec);
199 trace_xfs_refcount_delete_error(cur->bc_mp,
200 cur->bc_private.a.agno, error, _RET_IP_);
205 * Adjusting the Reference Count
207 * As stated elsewhere, the reference count btree (refcbt) stores
208 * >1 reference counts for extents of physical blocks. In this
209 * operation, we're either raising or lowering the reference count of
210 * some subrange stored in the tree:
212 * <------ adjustment range ------>
213 * ----+ +---+-----+ +--+--------+---------
214 * 2 | | 3 | 4 | |17| 55 | 10
215 * ----+ +---+-----+ +--+--------+---------
216 * X axis is physical blocks number;
217 * reference counts are the numbers inside the rectangles
219 * The first thing we need to do is to ensure that there are no
220 * refcount extents crossing either boundary of the range to be
221 * adjusted. For any extent that does cross a boundary, split it into
222 * two extents so that we can increment the refcount of one of the
225 * <------ adjustment range ------>
226 * ----+ +---+-----+ +--+--------+----+----
227 * 2 | | 3 | 2 | |17| 55 | 10 | 10
228 * ----+ +---+-----+ +--+--------+----+----
230 * For this next step, let's assume that all the physical blocks in
231 * the adjustment range are mapped to a file and are therefore in use
232 * at least once. Therefore, we can infer that any gap in the
233 * refcount tree within the adjustment range represents a physical
234 * extent with refcount == 1:
236 * <------ adjustment range ------>
237 * ----+---+---+-----+-+--+--------+----+----
238 * 2 |"1"| 3 | 2 |1|17| 55 | 10 | 10
239 * ----+---+---+-----+-+--+--------+----+----
242 * For each extent that falls within the interval range, figure out
243 * which extent is to the left or the right of that extent. Now we
244 * have a left, current, and right extent. If the new reference count
245 * of the center extent enables us to merge left, center, and right
246 * into one record covering all three, do so. If the center extent is
247 * at the left end of the range, abuts the left extent, and its new
248 * reference count matches the left extent's record, then merge them.
249 * If the center extent is at the right end of the range, abuts the
250 * right extent, and the reference counts match, merge those. In the
251 * example, we can left merge (assuming an increment operation):
253 * <------ adjustment range ------>
254 * --------+---+-----+-+--+--------+----+----
255 * 2 | 3 | 2 |1|17| 55 | 10 | 10
256 * --------+---+-----+-+--+--------+----+----
259 * For all other extents within the range, adjust the reference count
260 * or delete it if the refcount falls below 2. If we were
261 * incrementing, the end result looks like this:
263 * <------ adjustment range ------>
264 * --------+---+-----+-+--+--------+----+----
265 * 2 | 4 | 3 |2|18| 56 | 11 | 10
266 * --------+---+-----+-+--+--------+----+----
268 * The result of a decrement operation looks as such:
270 * <------ adjustment range ------>
271 * ----+ +---+ +--+--------+----+----
272 * 2 | | 2 | |16| 54 | 9 | 10
273 * ----+ +---+ +--+--------+----+----
276 * The blocks marked "D" are freed; the blocks marked "1" are only
277 * referenced once and therefore the record is removed from the
281 /* Next block after this extent. */
282 static inline xfs_agblock_t
284 struct xfs_refcount_irec *rc)
286 return rc->rc_startblock + rc->rc_blockcount;
290 * Split a refcount extent that crosses agbno.
293 xfs_refcount_split_extent(
294 struct xfs_btree_cur *cur,
298 struct xfs_refcount_irec rcext, tmp;
302 *shape_changed = false;
303 error = xfs_refcount_lookup_le(cur, agbno, &found_rec);
309 error = xfs_refcount_get_rec(cur, &rcext, &found_rec);
312 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
313 if (rcext.rc_startblock == agbno || xfs_refc_next(&rcext) <= agbno)
316 *shape_changed = true;
317 trace_xfs_refcount_split_extent(cur->bc_mp, cur->bc_private.a.agno,
320 /* Establish the right extent. */
322 tmp.rc_startblock = agbno;
323 tmp.rc_blockcount -= (agbno - rcext.rc_startblock);
324 error = xfs_refcount_update(cur, &tmp);
328 /* Insert the left extent. */
330 tmp.rc_blockcount = agbno - rcext.rc_startblock;
331 error = xfs_refcount_insert(cur, &tmp, &found_rec);
334 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
338 trace_xfs_refcount_split_extent_error(cur->bc_mp,
339 cur->bc_private.a.agno, error, _RET_IP_);
344 * Merge the left, center, and right extents.
347 xfs_refcount_merge_center_extents(
348 struct xfs_btree_cur *cur,
349 struct xfs_refcount_irec *left,
350 struct xfs_refcount_irec *center,
351 struct xfs_refcount_irec *right,
352 unsigned long long extlen,
353 xfs_agblock_t *agbno,
359 trace_xfs_refcount_merge_center_extents(cur->bc_mp,
360 cur->bc_private.a.agno, left, center, right);
363 * Make sure the center and right extents are not in the btree.
364 * If the center extent was synthesized, the first delete call
365 * removes the right extent and we skip the second deletion.
366 * If center and right were in the btree, then the first delete
367 * call removes the center and the second one removes the right
370 error = xfs_refcount_lookup_ge(cur, center->rc_startblock,
374 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
376 error = xfs_refcount_delete(cur, &found_rec);
379 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
381 if (center->rc_refcount > 1) {
382 error = xfs_refcount_delete(cur, &found_rec);
385 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
389 /* Enlarge the left extent. */
390 error = xfs_refcount_lookup_le(cur, left->rc_startblock,
394 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
396 left->rc_blockcount = extlen;
397 error = xfs_refcount_update(cur, left);
405 trace_xfs_refcount_merge_center_extents_error(cur->bc_mp,
406 cur->bc_private.a.agno, error, _RET_IP_);
411 * Merge with the left extent.
414 xfs_refcount_merge_left_extent(
415 struct xfs_btree_cur *cur,
416 struct xfs_refcount_irec *left,
417 struct xfs_refcount_irec *cleft,
418 xfs_agblock_t *agbno,
424 trace_xfs_refcount_merge_left_extent(cur->bc_mp,
425 cur->bc_private.a.agno, left, cleft);
427 /* If the extent at agbno (cleft) wasn't synthesized, remove it. */
428 if (cleft->rc_refcount > 1) {
429 error = xfs_refcount_lookup_le(cur, cleft->rc_startblock,
433 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
436 error = xfs_refcount_delete(cur, &found_rec);
439 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
443 /* Enlarge the left extent. */
444 error = xfs_refcount_lookup_le(cur, left->rc_startblock,
448 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
450 left->rc_blockcount += cleft->rc_blockcount;
451 error = xfs_refcount_update(cur, left);
455 *agbno += cleft->rc_blockcount;
456 *aglen -= cleft->rc_blockcount;
460 trace_xfs_refcount_merge_left_extent_error(cur->bc_mp,
461 cur->bc_private.a.agno, error, _RET_IP_);
466 * Merge with the right extent.
469 xfs_refcount_merge_right_extent(
470 struct xfs_btree_cur *cur,
471 struct xfs_refcount_irec *right,
472 struct xfs_refcount_irec *cright,
473 xfs_agblock_t *agbno,
479 trace_xfs_refcount_merge_right_extent(cur->bc_mp,
480 cur->bc_private.a.agno, cright, right);
483 * If the extent ending at agbno+aglen (cright) wasn't synthesized,
486 if (cright->rc_refcount > 1) {
487 error = xfs_refcount_lookup_le(cur, cright->rc_startblock,
491 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
494 error = xfs_refcount_delete(cur, &found_rec);
497 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
501 /* Enlarge the right extent. */
502 error = xfs_refcount_lookup_le(cur, right->rc_startblock,
506 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
508 right->rc_startblock -= cright->rc_blockcount;
509 right->rc_blockcount += cright->rc_blockcount;
510 error = xfs_refcount_update(cur, right);
514 *aglen -= cright->rc_blockcount;
518 trace_xfs_refcount_merge_right_extent_error(cur->bc_mp,
519 cur->bc_private.a.agno, error, _RET_IP_);
523 #define XFS_FIND_RCEXT_SHARED 1
524 #define XFS_FIND_RCEXT_COW 2
526 * Find the left extent and the one after it (cleft). This function assumes
527 * that we've already split any extent crossing agbno.
530 xfs_refcount_find_left_extents(
531 struct xfs_btree_cur *cur,
532 struct xfs_refcount_irec *left,
533 struct xfs_refcount_irec *cleft,
538 struct xfs_refcount_irec tmp;
542 left->rc_startblock = cleft->rc_startblock = NULLAGBLOCK;
543 error = xfs_refcount_lookup_le(cur, agbno - 1, &found_rec);
549 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
552 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
554 if (xfs_refc_next(&tmp) != agbno)
556 if ((flags & XFS_FIND_RCEXT_SHARED) && tmp.rc_refcount < 2)
558 if ((flags & XFS_FIND_RCEXT_COW) && tmp.rc_refcount > 1)
560 /* We have a left extent; retrieve (or invent) the next right one */
563 error = xfs_btree_increment(cur, 0, &found_rec);
567 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
570 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
573 /* if tmp starts at the end of our range, just use that */
574 if (tmp.rc_startblock == agbno)
578 * There's a gap in the refcntbt at the start of the
579 * range we're interested in (refcount == 1) so
580 * synthesize the implied extent and pass it back.
581 * We assume here that the agbno/aglen range was
582 * passed in from a data fork extent mapping and
583 * therefore is allocated to exactly one owner.
585 cleft->rc_startblock = agbno;
586 cleft->rc_blockcount = min(aglen,
587 tmp.rc_startblock - agbno);
588 cleft->rc_refcount = 1;
592 * No extents, so pretend that there's one covering the whole
595 cleft->rc_startblock = agbno;
596 cleft->rc_blockcount = aglen;
597 cleft->rc_refcount = 1;
599 trace_xfs_refcount_find_left_extent(cur->bc_mp, cur->bc_private.a.agno,
604 trace_xfs_refcount_find_left_extent_error(cur->bc_mp,
605 cur->bc_private.a.agno, error, _RET_IP_);
610 * Find the right extent and the one before it (cright). This function
611 * assumes that we've already split any extents crossing agbno + aglen.
614 xfs_refcount_find_right_extents(
615 struct xfs_btree_cur *cur,
616 struct xfs_refcount_irec *right,
617 struct xfs_refcount_irec *cright,
622 struct xfs_refcount_irec tmp;
626 right->rc_startblock = cright->rc_startblock = NULLAGBLOCK;
627 error = xfs_refcount_lookup_ge(cur, agbno + aglen, &found_rec);
633 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
636 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1, out_error);
638 if (tmp.rc_startblock != agbno + aglen)
640 if ((flags & XFS_FIND_RCEXT_SHARED) && tmp.rc_refcount < 2)
642 if ((flags & XFS_FIND_RCEXT_COW) && tmp.rc_refcount > 1)
644 /* We have a right extent; retrieve (or invent) the next left one */
647 error = xfs_btree_decrement(cur, 0, &found_rec);
651 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);
654 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, found_rec == 1,
657 /* if tmp ends at the end of our range, just use that */
658 if (xfs_refc_next(&tmp) == agbno + aglen)
662 * There's a gap in the refcntbt at the end of the
663 * range we're interested in (refcount == 1) so
664 * create the implied extent and pass it back.
665 * We assume here that the agbno/aglen range was
666 * passed in from a data fork extent mapping and
667 * therefore is allocated to exactly one owner.
669 cright->rc_startblock = max(agbno, xfs_refc_next(&tmp));
670 cright->rc_blockcount = right->rc_startblock -
671 cright->rc_startblock;
672 cright->rc_refcount = 1;
676 * No extents, so pretend that there's one covering the whole
679 cright->rc_startblock = agbno;
680 cright->rc_blockcount = aglen;
681 cright->rc_refcount = 1;
683 trace_xfs_refcount_find_right_extent(cur->bc_mp, cur->bc_private.a.agno,
684 cright, right, agbno + aglen);
688 trace_xfs_refcount_find_right_extent_error(cur->bc_mp,
689 cur->bc_private.a.agno, error, _RET_IP_);
693 /* Is this extent valid? */
696 struct xfs_refcount_irec *rc)
698 return rc->rc_startblock != NULLAGBLOCK;
702 * Try to merge with any extents on the boundaries of the adjustment range.
705 xfs_refcount_merge_extents(
706 struct xfs_btree_cur *cur,
707 xfs_agblock_t *agbno,
709 enum xfs_refc_adjust_op adjust,
713 struct xfs_refcount_irec left = {0}, cleft = {0};
714 struct xfs_refcount_irec cright = {0}, right = {0};
716 unsigned long long ulen;
719 *shape_changed = false;
721 * Find the extent just below agbno [left], just above agbno [cleft],
722 * just below (agbno + aglen) [cright], and just above (agbno + aglen)
725 error = xfs_refcount_find_left_extents(cur, &left, &cleft, *agbno,
729 error = xfs_refcount_find_right_extents(cur, &right, &cright, *agbno,
734 /* No left or right extent to merge; exit. */
735 if (!xfs_refc_valid(&left) && !xfs_refc_valid(&right))
738 cequal = (cleft.rc_startblock == cright.rc_startblock) &&
739 (cleft.rc_blockcount == cright.rc_blockcount);
741 /* Try to merge left, cleft, and right. cleft must == cright. */
742 ulen = (unsigned long long)left.rc_blockcount + cleft.rc_blockcount +
744 if (xfs_refc_valid(&left) && xfs_refc_valid(&right) &&
745 xfs_refc_valid(&cleft) && xfs_refc_valid(&cright) && cequal &&
746 left.rc_refcount == cleft.rc_refcount + adjust &&
747 right.rc_refcount == cleft.rc_refcount + adjust &&
748 ulen < MAXREFCEXTLEN) {
749 *shape_changed = true;
750 return xfs_refcount_merge_center_extents(cur, &left, &cleft,
751 &right, ulen, agbno, aglen);
754 /* Try to merge left and cleft. */
755 ulen = (unsigned long long)left.rc_blockcount + cleft.rc_blockcount;
756 if (xfs_refc_valid(&left) && xfs_refc_valid(&cleft) &&
757 left.rc_refcount == cleft.rc_refcount + adjust &&
758 ulen < MAXREFCEXTLEN) {
759 *shape_changed = true;
760 error = xfs_refcount_merge_left_extent(cur, &left, &cleft,
766 * If we just merged left + cleft and cleft == cright,
767 * we no longer have a cright to merge with right. We're done.
773 /* Try to merge cright and right. */
774 ulen = (unsigned long long)right.rc_blockcount + cright.rc_blockcount;
775 if (xfs_refc_valid(&right) && xfs_refc_valid(&cright) &&
776 right.rc_refcount == cright.rc_refcount + adjust &&
777 ulen < MAXREFCEXTLEN) {
778 *shape_changed = true;
779 return xfs_refcount_merge_right_extent(cur, &right, &cright,
787 * XXX: This is a pretty hand-wavy estimate. The penalty for guessing
788 * true incorrectly is a shutdown FS; the penalty for guessing false
789 * incorrectly is more transaction rolls than might be necessary.
790 * Be conservative here.
793 xfs_refcount_still_have_space(
794 struct xfs_btree_cur *cur)
796 unsigned long overhead;
798 overhead = cur->bc_private.a.priv.refc.shape_changes *
799 xfs_allocfree_log_count(cur->bc_mp, 1);
800 overhead *= cur->bc_mp->m_sb.sb_blocksize;
803 * Only allow 2 refcount extent updates per transaction if the
804 * refcount continue update "error" has been injected.
806 if (cur->bc_private.a.priv.refc.nr_ops > 2 &&
807 XFS_TEST_ERROR(false, cur->bc_mp,
808 XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE,
809 XFS_RANDOM_REFCOUNT_CONTINUE_UPDATE))
812 if (cur->bc_private.a.priv.refc.nr_ops == 0)
814 else if (overhead > cur->bc_tp->t_log_res)
816 return cur->bc_tp->t_log_res - overhead >
817 cur->bc_private.a.priv.refc.nr_ops * XFS_REFCOUNT_ITEM_OVERHEAD;
821 * Adjust the refcounts of middle extents. At this point we should have
822 * split extents that crossed the adjustment range; merged with adjacent
823 * extents; and updated agbno/aglen to reflect the merges. Therefore,
824 * all we have to do is update the extents inside [agbno, agbno + aglen].
827 xfs_refcount_adjust_extents(
828 struct xfs_btree_cur *cur,
829 xfs_agblock_t *agbno,
831 enum xfs_refc_adjust_op adj,
832 struct xfs_defer_ops *dfops,
833 struct xfs_owner_info *oinfo)
835 struct xfs_refcount_irec ext, tmp;
837 int found_rec, found_tmp;
840 /* Merging did all the work already. */
844 error = xfs_refcount_lookup_ge(cur, *agbno, &found_rec);
848 while (*aglen > 0 && xfs_refcount_still_have_space(cur)) {
849 error = xfs_refcount_get_rec(cur, &ext, &found_rec);
853 ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks;
854 ext.rc_blockcount = 0;
859 * Deal with a hole in the refcount tree; if a file maps to
860 * these blocks and there's no refcountbt record, pretend that
861 * there is one with refcount == 1.
863 if (ext.rc_startblock != *agbno) {
864 tmp.rc_startblock = *agbno;
865 tmp.rc_blockcount = min(*aglen,
866 ext.rc_startblock - *agbno);
867 tmp.rc_refcount = 1 + adj;
868 trace_xfs_refcount_modify_extent(cur->bc_mp,
869 cur->bc_private.a.agno, &tmp);
872 * Either cover the hole (increment) or
873 * delete the range (decrement).
875 if (tmp.rc_refcount) {
876 error = xfs_refcount_insert(cur, &tmp,
880 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
881 found_tmp == 1, out_error);
882 cur->bc_private.a.priv.refc.nr_ops++;
884 fsbno = XFS_AGB_TO_FSB(cur->bc_mp,
885 cur->bc_private.a.agno,
887 xfs_bmap_add_free(cur->bc_mp, dfops, fsbno,
888 tmp.rc_blockcount, oinfo);
891 (*agbno) += tmp.rc_blockcount;
892 (*aglen) -= tmp.rc_blockcount;
894 error = xfs_refcount_lookup_ge(cur, *agbno,
900 /* Stop if there's nothing left to modify */
901 if (*aglen == 0 || !xfs_refcount_still_have_space(cur))
905 * Adjust the reference count and either update the tree
906 * (incr) or free the blocks (decr).
908 if (ext.rc_refcount == MAXREFCOUNT)
910 ext.rc_refcount += adj;
911 trace_xfs_refcount_modify_extent(cur->bc_mp,
912 cur->bc_private.a.agno, &ext);
913 if (ext.rc_refcount > 1) {
914 error = xfs_refcount_update(cur, &ext);
917 cur->bc_private.a.priv.refc.nr_ops++;
918 } else if (ext.rc_refcount == 1) {
919 error = xfs_refcount_delete(cur, &found_rec);
922 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
923 found_rec == 1, out_error);
924 cur->bc_private.a.priv.refc.nr_ops++;
927 fsbno = XFS_AGB_TO_FSB(cur->bc_mp,
928 cur->bc_private.a.agno,
930 xfs_bmap_add_free(cur->bc_mp, dfops, fsbno,
931 ext.rc_blockcount, oinfo);
935 error = xfs_btree_increment(cur, 0, &found_rec);
940 (*agbno) += ext.rc_blockcount;
941 (*aglen) -= ext.rc_blockcount;
946 trace_xfs_refcount_modify_extent_error(cur->bc_mp,
947 cur->bc_private.a.agno, error, _RET_IP_);
951 /* Adjust the reference count of a range of AG blocks. */
954 struct xfs_btree_cur *cur,
957 xfs_agblock_t *new_agbno,
958 xfs_extlen_t *new_aglen,
959 enum xfs_refc_adjust_op adj,
960 struct xfs_defer_ops *dfops,
961 struct xfs_owner_info *oinfo)
964 int shape_changes = 0;
969 if (adj == XFS_REFCOUNT_ADJUST_INCREASE)
970 trace_xfs_refcount_increase(cur->bc_mp, cur->bc_private.a.agno,
973 trace_xfs_refcount_decrease(cur->bc_mp, cur->bc_private.a.agno,
977 * Ensure that no rcextents cross the boundary of the adjustment range.
979 error = xfs_refcount_split_extent(cur, agbno, &shape_changed);
985 error = xfs_refcount_split_extent(cur, agbno + aglen, &shape_changed);
992 * Try to merge with the left or right extents of the range.
994 error = xfs_refcount_merge_extents(cur, new_agbno, new_aglen, adj,
995 XFS_FIND_RCEXT_SHARED, &shape_changed);
1001 cur->bc_private.a.priv.refc.shape_changes++;
1003 /* Now that we've taken care of the ends, adjust the middle extents */
1004 error = xfs_refcount_adjust_extents(cur, new_agbno, new_aglen,
1012 trace_xfs_refcount_adjust_error(cur->bc_mp, cur->bc_private.a.agno,
1017 /* Clean up after calling xfs_refcount_finish_one. */
1019 xfs_refcount_finish_one_cleanup(
1020 struct xfs_trans *tp,
1021 struct xfs_btree_cur *rcur,
1024 struct xfs_buf *agbp;
1028 agbp = rcur->bc_private.a.agbp;
1029 xfs_btree_del_cursor(rcur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
1031 xfs_trans_brelse(tp, agbp);
1035 * Process one of the deferred refcount operations. We pass back the
1036 * btree cursor to maintain our lock on the btree between calls.
1037 * This saves time and eliminates a buffer deadlock between the
1038 * superblock and the AGF because we'll always grab them in the same
1042 xfs_refcount_finish_one(
1043 struct xfs_trans *tp,
1044 struct xfs_defer_ops *dfops,
1045 enum xfs_refcount_intent_type type,
1046 xfs_fsblock_t startblock,
1047 xfs_extlen_t blockcount,
1048 xfs_fsblock_t *new_fsb,
1049 xfs_extlen_t *new_len,
1050 struct xfs_btree_cur **pcur)
1052 struct xfs_mount *mp = tp->t_mountp;
1053 struct xfs_btree_cur *rcur;
1054 struct xfs_buf *agbp = NULL;
1056 xfs_agnumber_t agno;
1058 xfs_agblock_t new_agbno;
1059 unsigned long nr_ops = 0;
1060 int shape_changes = 0;
1062 agno = XFS_FSB_TO_AGNO(mp, startblock);
1063 ASSERT(agno != NULLAGNUMBER);
1064 bno = XFS_FSB_TO_AGBNO(mp, startblock);
1066 trace_xfs_refcount_deferred(mp, XFS_FSB_TO_AGNO(mp, startblock),
1067 type, XFS_FSB_TO_AGBNO(mp, startblock),
1070 if (XFS_TEST_ERROR(false, mp,
1071 XFS_ERRTAG_REFCOUNT_FINISH_ONE,
1072 XFS_RANDOM_REFCOUNT_FINISH_ONE))
1076 * If we haven't gotten a cursor or the cursor AG doesn't match
1077 * the startblock, get one now.
1080 if (rcur != NULL && rcur->bc_private.a.agno != agno) {
1081 nr_ops = rcur->bc_private.a.priv.refc.nr_ops;
1082 shape_changes = rcur->bc_private.a.priv.refc.shape_changes;
1083 xfs_refcount_finish_one_cleanup(tp, rcur, 0);
1088 error = xfs_alloc_read_agf(tp->t_mountp, tp, agno,
1089 XFS_ALLOC_FLAG_FREEING, &agbp);
1093 return -EFSCORRUPTED;
1095 rcur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, dfops);
1100 rcur->bc_private.a.priv.refc.nr_ops = nr_ops;
1101 rcur->bc_private.a.priv.refc.shape_changes = shape_changes;
1106 case XFS_REFCOUNT_INCREASE:
1107 error = xfs_refcount_adjust(rcur, bno, blockcount, &new_agbno,
1108 new_len, XFS_REFCOUNT_ADJUST_INCREASE, dfops, NULL);
1109 *new_fsb = XFS_AGB_TO_FSB(mp, agno, new_agbno);
1111 case XFS_REFCOUNT_DECREASE:
1112 error = xfs_refcount_adjust(rcur, bno, blockcount, &new_agbno,
1113 new_len, XFS_REFCOUNT_ADJUST_DECREASE, dfops, NULL);
1114 *new_fsb = XFS_AGB_TO_FSB(mp, agno, new_agbno);
1116 case XFS_REFCOUNT_ALLOC_COW:
1117 *new_fsb = startblock + blockcount;
1119 error = __xfs_refcount_cow_alloc(rcur, bno, blockcount, dfops);
1121 case XFS_REFCOUNT_FREE_COW:
1122 *new_fsb = startblock + blockcount;
1124 error = __xfs_refcount_cow_free(rcur, bno, blockcount, dfops);
1128 error = -EFSCORRUPTED;
1130 if (!error && *new_len > 0)
1131 trace_xfs_refcount_finish_one_leftover(mp, agno, type,
1132 bno, blockcount, new_agbno, *new_len);
1136 xfs_trans_brelse(tp, agbp);
1142 * Record a refcount intent for later processing.
1146 struct xfs_mount *mp,
1147 struct xfs_defer_ops *dfops,
1148 enum xfs_refcount_intent_type type,
1149 xfs_fsblock_t startblock,
1150 xfs_extlen_t blockcount)
1152 struct xfs_refcount_intent *ri;
1154 trace_xfs_refcount_defer(mp, XFS_FSB_TO_AGNO(mp, startblock),
1155 type, XFS_FSB_TO_AGBNO(mp, startblock),
1158 ri = kmem_alloc(sizeof(struct xfs_refcount_intent),
1159 KM_SLEEP | KM_NOFS);
1160 INIT_LIST_HEAD(&ri->ri_list);
1162 ri->ri_startblock = startblock;
1163 ri->ri_blockcount = blockcount;
1165 xfs_defer_add(dfops, XFS_DEFER_OPS_TYPE_REFCOUNT, &ri->ri_list);
1170 * Increase the reference count of the blocks backing a file's extent.
1173 xfs_refcount_increase_extent(
1174 struct xfs_mount *mp,
1175 struct xfs_defer_ops *dfops,
1176 struct xfs_bmbt_irec *PREV)
1178 if (!xfs_sb_version_hasreflink(&mp->m_sb))
1181 return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_INCREASE,
1182 PREV->br_startblock, PREV->br_blockcount);
1186 * Decrease the reference count of the blocks backing a file's extent.
1189 xfs_refcount_decrease_extent(
1190 struct xfs_mount *mp,
1191 struct xfs_defer_ops *dfops,
1192 struct xfs_bmbt_irec *PREV)
1194 if (!xfs_sb_version_hasreflink(&mp->m_sb))
1197 return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_DECREASE,
1198 PREV->br_startblock, PREV->br_blockcount);
1202 * Given an AG extent, find the lowest-numbered run of shared blocks
1203 * within that range and return the range in fbno/flen. If
1204 * find_end_of_shared is set, return the longest contiguous extent of
1205 * shared blocks; if not, just return the first extent we find. If no
1206 * shared blocks are found, fbno and flen will be set to NULLAGBLOCK
1207 * and 0, respectively.
1210 xfs_refcount_find_shared(
1211 struct xfs_btree_cur *cur,
1212 xfs_agblock_t agbno,
1214 xfs_agblock_t *fbno,
1216 bool find_end_of_shared)
1218 struct xfs_refcount_irec tmp;
1223 trace_xfs_refcount_find_shared(cur->bc_mp, cur->bc_private.a.agno,
1226 /* By default, skip the whole range */
1227 *fbno = NULLAGBLOCK;
1230 /* Try to find a refcount extent that crosses the start */
1231 error = xfs_refcount_lookup_le(cur, agbno, &have);
1235 /* No left extent, look at the next one */
1236 error = xfs_btree_increment(cur, 0, &have);
1242 error = xfs_refcount_get_rec(cur, &tmp, &i);
1245 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, out_error);
1247 /* If the extent ends before the start, look at the next one */
1248 if (tmp.rc_startblock + tmp.rc_blockcount <= agbno) {
1249 error = xfs_btree_increment(cur, 0, &have);
1254 error = xfs_refcount_get_rec(cur, &tmp, &i);
1257 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, out_error);
1260 /* If the extent starts after the range we want, bail out */
1261 if (tmp.rc_startblock >= agbno + aglen)
1264 /* We found the start of a shared extent! */
1265 if (tmp.rc_startblock < agbno) {
1266 tmp.rc_blockcount -= (agbno - tmp.rc_startblock);
1267 tmp.rc_startblock = agbno;
1270 *fbno = tmp.rc_startblock;
1271 *flen = min(tmp.rc_blockcount, agbno + aglen - *fbno);
1272 if (!find_end_of_shared)
1275 /* Otherwise, find the end of this shared extent */
1276 while (*fbno + *flen < agbno + aglen) {
1277 error = xfs_btree_increment(cur, 0, &have);
1282 error = xfs_refcount_get_rec(cur, &tmp, &i);
1285 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp, i == 1, out_error);
1286 if (tmp.rc_startblock >= agbno + aglen ||
1287 tmp.rc_startblock != *fbno + *flen)
1289 *flen = min(*flen + tmp.rc_blockcount, agbno + aglen - *fbno);
1293 trace_xfs_refcount_find_shared_result(cur->bc_mp,
1294 cur->bc_private.a.agno, *fbno, *flen);
1298 trace_xfs_refcount_find_shared_error(cur->bc_mp,
1299 cur->bc_private.a.agno, error, _RET_IP_);
1304 * Recovering CoW Blocks After a Crash
1306 * Due to the way that the copy on write mechanism works, there's a window of
1307 * opportunity in which we can lose track of allocated blocks during a crash.
1308 * Because CoW uses delayed allocation in the in-core CoW fork, writeback
1309 * causes blocks to be allocated and stored in the CoW fork. The blocks are
1310 * no longer in the free space btree but are not otherwise recorded anywhere
1311 * until the write completes and the blocks are mapped into the file. A crash
1312 * in between allocation and remapping results in the replacement blocks being
1313 * lost. This situation is exacerbated by the CoW extent size hint because
1314 * allocations can hang around for long time.
1316 * However, there is a place where we can record these allocations before they
1317 * become mappings -- the reference count btree. The btree does not record
1318 * extents with refcount == 1, so we can record allocations with a refcount of
1319 * 1. Blocks being used for CoW writeout cannot be shared, so there should be
1320 * no conflict with shared block records. These mappings should be created
1321 * when we allocate blocks to the CoW fork and deleted when they're removed
1322 * from the CoW fork.
1324 * Minor nit: records for in-progress CoW allocations and records for shared
1325 * extents must never be merged, to preserve the property that (except for CoW
1326 * allocations) there are no refcount btree entries with refcount == 1. The
1327 * only time this could potentially happen is when unsharing a block that's
1328 * adjacent to CoW allocations, so we must be careful to avoid this.
1330 * At mount time we recover lost CoW allocations by searching the refcount
1331 * btree for these refcount == 1 mappings. These represent CoW allocations
1332 * that were in progress at the time the filesystem went down, so we can free
1333 * them to get the space back.
1335 * This mechanism is superior to creating EFIs for unmapped CoW extents for
1336 * several reasons -- first, EFIs pin the tail of the log and would have to be
1337 * periodically relogged to avoid filling up the log. Second, CoW completions
1338 * will have to file an EFD and create new EFIs for whatever remains in the
1339 * CoW fork; this partially takes care of (1) but extent-size reservations
1340 * will have to periodically relog even if there's no writeout in progress.
1341 * This can happen if the CoW extent size hint is set, which you really want.
1342 * Third, EFIs cannot currently be automatically relogged into newer
1343 * transactions to advance the log tail. Fourth, stuffing the log full of
1344 * EFIs places an upper bound on the number of CoW allocations that can be
1345 * held filesystem-wide at any given time. Recording them in the refcount
1346 * btree doesn't require us to maintain any state in memory and doesn't pin
1350 * Adjust the refcounts of CoW allocations. These allocations are "magic"
1351 * in that they're not referenced anywhere else in the filesystem, so we
1352 * stash them in the refcount btree with a refcount of 1 until either file
1353 * remapping (or CoW cancellation) happens.
1356 xfs_refcount_adjust_cow_extents(
1357 struct xfs_btree_cur *cur,
1358 xfs_agblock_t agbno,
1360 enum xfs_refc_adjust_op adj,
1361 struct xfs_defer_ops *dfops,
1362 struct xfs_owner_info *oinfo)
1364 struct xfs_refcount_irec ext, tmp;
1366 int found_rec, found_tmp;
1371 /* Find any overlapping refcount records */
1372 error = xfs_refcount_lookup_ge(cur, agbno, &found_rec);
1375 error = xfs_refcount_get_rec(cur, &ext, &found_rec);
1379 ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks +
1381 ext.rc_blockcount = 0;
1382 ext.rc_refcount = 0;
1386 case XFS_REFCOUNT_ADJUST_COW_ALLOC:
1387 /* Adding a CoW reservation, there should be nothing here. */
1388 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
1389 ext.rc_startblock >= agbno + aglen, out_error);
1391 tmp.rc_startblock = agbno;
1392 tmp.rc_blockcount = aglen;
1393 tmp.rc_refcount = 1;
1394 trace_xfs_refcount_modify_extent(cur->bc_mp,
1395 cur->bc_private.a.agno, &tmp);
1397 error = xfs_refcount_insert(cur, &tmp,
1401 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
1402 found_tmp == 1, out_error);
1404 case XFS_REFCOUNT_ADJUST_COW_FREE:
1405 /* Removing a CoW reservation, there should be one extent. */
1406 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
1407 ext.rc_startblock == agbno, out_error);
1408 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
1409 ext.rc_blockcount == aglen, out_error);
1410 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
1411 ext.rc_refcount == 1, out_error);
1413 ext.rc_refcount = 0;
1414 trace_xfs_refcount_modify_extent(cur->bc_mp,
1415 cur->bc_private.a.agno, &ext);
1416 error = xfs_refcount_delete(cur, &found_rec);
1419 XFS_WANT_CORRUPTED_GOTO(cur->bc_mp,
1420 found_rec == 1, out_error);
1428 trace_xfs_refcount_modify_extent_error(cur->bc_mp,
1429 cur->bc_private.a.agno, error, _RET_IP_);
1434 * Add or remove refcount btree entries for CoW reservations.
1437 xfs_refcount_adjust_cow(
1438 struct xfs_btree_cur *cur,
1439 xfs_agblock_t agbno,
1441 enum xfs_refc_adjust_op adj,
1442 struct xfs_defer_ops *dfops)
1447 agbno += XFS_REFC_COW_START;
1450 * Ensure that no rcextents cross the boundary of the adjustment range.
1452 error = xfs_refcount_split_extent(cur, agbno, &shape_changed);
1456 error = xfs_refcount_split_extent(cur, agbno + aglen, &shape_changed);
1461 * Try to merge with the left or right extents of the range.
1463 error = xfs_refcount_merge_extents(cur, &agbno, &aglen, adj,
1464 XFS_FIND_RCEXT_COW, &shape_changed);
1468 /* Now that we've taken care of the ends, adjust the middle extents */
1469 error = xfs_refcount_adjust_cow_extents(cur, agbno, aglen, adj,
1477 trace_xfs_refcount_adjust_cow_error(cur->bc_mp, cur->bc_private.a.agno,
1483 * Record a CoW allocation in the refcount btree.
1486 __xfs_refcount_cow_alloc(
1487 struct xfs_btree_cur *rcur,
1488 xfs_agblock_t agbno,
1490 struct xfs_defer_ops *dfops)
1494 trace_xfs_refcount_cow_increase(rcur->bc_mp, rcur->bc_private.a.agno,
1497 /* Add refcount btree reservation */
1498 error = xfs_refcount_adjust_cow(rcur, agbno, aglen,
1499 XFS_REFCOUNT_ADJUST_COW_ALLOC, dfops);
1503 /* Add rmap entry */
1504 if (xfs_sb_version_hasrmapbt(&rcur->bc_mp->m_sb)) {
1505 error = xfs_rmap_alloc_extent(rcur->bc_mp, dfops,
1506 rcur->bc_private.a.agno,
1507 agbno, aglen, XFS_RMAP_OWN_COW);
1516 * Remove a CoW allocation from the refcount btree.
1519 __xfs_refcount_cow_free(
1520 struct xfs_btree_cur *rcur,
1521 xfs_agblock_t agbno,
1523 struct xfs_defer_ops *dfops)
1527 trace_xfs_refcount_cow_decrease(rcur->bc_mp, rcur->bc_private.a.agno,
1530 /* Remove refcount btree reservation */
1531 error = xfs_refcount_adjust_cow(rcur, agbno, aglen,
1532 XFS_REFCOUNT_ADJUST_COW_FREE, dfops);
1536 /* Remove rmap entry */
1537 if (xfs_sb_version_hasrmapbt(&rcur->bc_mp->m_sb)) {
1538 error = xfs_rmap_free_extent(rcur->bc_mp, dfops,
1539 rcur->bc_private.a.agno,
1540 agbno, aglen, XFS_RMAP_OWN_COW);
1548 /* Record a CoW staging extent in the refcount btree. */
1550 xfs_refcount_alloc_cow_extent(
1551 struct xfs_mount *mp,
1552 struct xfs_defer_ops *dfops,
1556 if (!xfs_sb_version_hasreflink(&mp->m_sb))
1559 return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_ALLOC_COW,
1563 /* Forget a CoW staging event in the refcount btree. */
1565 xfs_refcount_free_cow_extent(
1566 struct xfs_mount *mp,
1567 struct xfs_defer_ops *dfops,
1571 if (!xfs_sb_version_hasreflink(&mp->m_sb))
1574 return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_FREE_COW,
1578 struct xfs_refcount_recovery {
1579 struct list_head rr_list;
1580 struct xfs_refcount_irec rr_rrec;
1583 /* Stuff an extent on the recovery list. */
1585 xfs_refcount_recover_extent(
1586 struct xfs_btree_cur *cur,
1587 union xfs_btree_rec *rec,
1590 struct list_head *debris = priv;
1591 struct xfs_refcount_recovery *rr;
1593 if (be32_to_cpu(rec->refc.rc_refcount) != 1)
1594 return -EFSCORRUPTED;
1596 rr = kmem_alloc(sizeof(struct xfs_refcount_recovery), KM_SLEEP);
1597 xfs_refcount_btrec_to_irec(rec, &rr->rr_rrec);
1598 list_add_tail(&rr->rr_list, debris);
1603 /* Find and remove leftover CoW reservations. */
1605 xfs_refcount_recover_cow_leftovers(
1606 struct xfs_mount *mp,
1607 xfs_agnumber_t agno)
1609 struct xfs_trans *tp;
1610 struct xfs_btree_cur *cur;
1611 struct xfs_buf *agbp;
1612 struct xfs_refcount_recovery *rr, *n;
1613 struct list_head debris;
1614 union xfs_btree_irec low;
1615 union xfs_btree_irec high;
1616 struct xfs_defer_ops dfops;
1618 xfs_agblock_t agbno;
1621 if (mp->m_sb.sb_agblocks >= XFS_REFC_COW_START)
1624 INIT_LIST_HEAD(&debris);
1627 * In this first part, we use an empty transaction to gather up
1628 * all the leftover CoW extents so that we can subsequently
1629 * delete them. The empty transaction is used to avoid
1630 * a buffer lock deadlock if there happens to be a loop in the
1631 * refcountbt because we're allowed to re-grab a buffer that is
1632 * already attached to our transaction. When we're done
1633 * recording the CoW debris we cancel the (empty) transaction
1634 * and everything goes away cleanly.
1636 error = xfs_trans_alloc_empty(mp, &tp);
1640 error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
1647 cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, NULL);
1649 /* Find all the leftover CoW staging extents. */
1650 memset(&low, 0, sizeof(low));
1651 memset(&high, 0, sizeof(high));
1652 low.rc.rc_startblock = XFS_REFC_COW_START;
1653 high.rc.rc_startblock = -1U;
1654 error = xfs_btree_query_range(cur, &low, &high,
1655 xfs_refcount_recover_extent, &debris);
1658 xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
1659 xfs_trans_brelse(tp, agbp);
1660 xfs_trans_cancel(tp);
1662 /* Now iterate the list to free the leftovers */
1663 list_for_each_entry_safe(rr, n, &debris, rr_list) {
1664 /* Set up transaction. */
1665 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
1669 trace_xfs_refcount_recover_extent(mp, agno, &rr->rr_rrec);
1671 /* Free the orphan record */
1672 xfs_defer_init(&dfops, &fsb);
1673 agbno = rr->rr_rrec.rc_startblock - XFS_REFC_COW_START;
1674 fsb = XFS_AGB_TO_FSB(mp, agno, agbno);
1675 error = xfs_refcount_free_cow_extent(mp, &dfops, fsb,
1676 rr->rr_rrec.rc_blockcount);
1680 /* Free the block. */
1681 xfs_bmap_add_free(mp, &dfops, fsb,
1682 rr->rr_rrec.rc_blockcount, NULL);
1684 error = xfs_defer_finish(&tp, &dfops, NULL);
1688 error = xfs_trans_commit(tp);
1692 list_del(&rr->rr_list);
1698 xfs_defer_cancel(&dfops);
1700 xfs_trans_cancel(tp);
1702 /* Free the leftover list */
1703 list_for_each_entry_safe(rr, n, &debris, rr_list) {
1704 list_del(&rr->rr_list);
1710 xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
1711 xfs_trans_brelse(tp, agbp);