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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#include "xfs_health.h"27#include "xfs_refcount_item.h"28 29struct kmem_cache *xfs_refcount_intent_cache;30 31/* Allowable refcount adjustment amounts. */32enum xfs_refc_adjust_op {33 XFS_REFCOUNT_ADJUST_INCREASE = 1,34 XFS_REFCOUNT_ADJUST_DECREASE = -1,35 XFS_REFCOUNT_ADJUST_COW_ALLOC = 0,36 XFS_REFCOUNT_ADJUST_COW_FREE = -1,37};38 39STATIC int __xfs_refcount_cow_alloc(struct xfs_btree_cur *rcur,40 xfs_agblock_t agbno, xfs_extlen_t aglen);41STATIC int __xfs_refcount_cow_free(struct xfs_btree_cur *rcur,42 xfs_agblock_t agbno, xfs_extlen_t aglen);43 44/*45 * Look up the first record less than or equal to [bno, len] in the btree46 * given by cur.47 */48int49xfs_refcount_lookup_le(50 struct xfs_btree_cur *cur,51 enum xfs_refc_domain domain,52 xfs_agblock_t bno,53 int *stat)54{55 trace_xfs_refcount_lookup(cur,56 xfs_refcount_encode_startblock(bno, domain),57 XFS_LOOKUP_LE);58 cur->bc_rec.rc.rc_startblock = bno;59 cur->bc_rec.rc.rc_blockcount = 0;60 cur->bc_rec.rc.rc_domain = domain;61 return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);62}63 64/*65 * Look up the first record greater than or equal to [bno, len] in the btree66 * given by cur.67 */68int69xfs_refcount_lookup_ge(70 struct xfs_btree_cur *cur,71 enum xfs_refc_domain domain,72 xfs_agblock_t bno,73 int *stat)74{75 trace_xfs_refcount_lookup(cur,76 xfs_refcount_encode_startblock(bno, domain),77 XFS_LOOKUP_GE);78 cur->bc_rec.rc.rc_startblock = bno;79 cur->bc_rec.rc.rc_blockcount = 0;80 cur->bc_rec.rc.rc_domain = domain;81 return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);82}83 84/*85 * Look up the first record equal to [bno, len] in the btree86 * given by cur.87 */88int89xfs_refcount_lookup_eq(90 struct xfs_btree_cur *cur,91 enum xfs_refc_domain domain,92 xfs_agblock_t bno,93 int *stat)94{95 trace_xfs_refcount_lookup(cur,96 xfs_refcount_encode_startblock(bno, domain),97 XFS_LOOKUP_LE);98 cur->bc_rec.rc.rc_startblock = bno;99 cur->bc_rec.rc.rc_blockcount = 0;100 cur->bc_rec.rc.rc_domain = domain;101 return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);102}103 104/* Convert on-disk record to in-core format. */105void106xfs_refcount_btrec_to_irec(107 const union xfs_btree_rec *rec,108 struct xfs_refcount_irec *irec)109{110 uint32_t start;111 112 start = be32_to_cpu(rec->refc.rc_startblock);113 if (start & XFS_REFC_COWFLAG) {114 start &= ~XFS_REFC_COWFLAG;115 irec->rc_domain = XFS_REFC_DOMAIN_COW;116 } else {117 irec->rc_domain = XFS_REFC_DOMAIN_SHARED;118 }119 120 irec->rc_startblock = start;121 irec->rc_blockcount = be32_to_cpu(rec->refc.rc_blockcount);122 irec->rc_refcount = be32_to_cpu(rec->refc.rc_refcount);123}124 125/* Simple checks for refcount records. */126xfs_failaddr_t127xfs_refcount_check_irec(128 struct xfs_perag *pag,129 const struct xfs_refcount_irec *irec)130{131 if (irec->rc_blockcount == 0 || irec->rc_blockcount > MAXREFCEXTLEN)132 return __this_address;133 134 if (!xfs_refcount_check_domain(irec))135 return __this_address;136 137 /* check for valid extent range, including overflow */138 if (!xfs_verify_agbext(pag, irec->rc_startblock, irec->rc_blockcount))139 return __this_address;140 141 if (irec->rc_refcount == 0 || irec->rc_refcount > MAXREFCOUNT)142 return __this_address;143 144 return NULL;145}146 147static inline int148xfs_refcount_complain_bad_rec(149 struct xfs_btree_cur *cur,150 xfs_failaddr_t fa,151 const struct xfs_refcount_irec *irec)152{153 struct xfs_mount *mp = cur->bc_mp;154 155 xfs_warn(mp,156 "Refcount BTree record corruption in AG %d detected at %pS!",157 cur->bc_ag.pag->pag_agno, fa);158 xfs_warn(mp,159 "Start block 0x%x, block count 0x%x, references 0x%x",160 irec->rc_startblock, irec->rc_blockcount, irec->rc_refcount);161 xfs_btree_mark_sick(cur);162 return -EFSCORRUPTED;163}164 165/*166 * Get the data from the pointed-to record.167 */168int169xfs_refcount_get_rec(170 struct xfs_btree_cur *cur,171 struct xfs_refcount_irec *irec,172 int *stat)173{174 union xfs_btree_rec *rec;175 xfs_failaddr_t fa;176 int error;177 178 error = xfs_btree_get_rec(cur, &rec, stat);179 if (error || !*stat)180 return error;181 182 xfs_refcount_btrec_to_irec(rec, irec);183 fa = xfs_refcount_check_irec(cur->bc_ag.pag, irec);184 if (fa)185 return xfs_refcount_complain_bad_rec(cur, fa, irec);186 187 trace_xfs_refcount_get(cur, irec);188 return 0;189}190 191/*192 * Update the record referred to by cur to the value given193 * by [bno, len, refcount].194 * This either works (return 0) or gets an EFSCORRUPTED error.195 */196STATIC int197xfs_refcount_update(198 struct xfs_btree_cur *cur,199 struct xfs_refcount_irec *irec)200{201 union xfs_btree_rec rec;202 uint32_t start;203 int error;204 205 trace_xfs_refcount_update(cur, irec);206 207 start = xfs_refcount_encode_startblock(irec->rc_startblock,208 irec->rc_domain);209 rec.refc.rc_startblock = cpu_to_be32(start);210 rec.refc.rc_blockcount = cpu_to_be32(irec->rc_blockcount);211 rec.refc.rc_refcount = cpu_to_be32(irec->rc_refcount);212 213 error = xfs_btree_update(cur, &rec);214 if (error)215 trace_xfs_refcount_update_error(cur, error, _RET_IP_);216 return error;217}218 219/*220 * Insert the record referred to by cur to the value given221 * by [bno, len, refcount].222 * This either works (return 0) or gets an EFSCORRUPTED error.223 */224int225xfs_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, 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, error, _RET_IP_);251 return error;252}253 254/*255 * Remove the record referred to by cur, then set the pointer to the spot256 * where the record could be re-inserted, in case we want to increment or257 * decrement the cursor.258 * This either works (return 0) or gets an EFSCORRUPTED error.259 */260STATIC int261xfs_refcount_delete(262 struct xfs_btree_cur *cur,263 int *i)264{265 struct xfs_refcount_irec irec;266 int found_rec;267 int error;268 269 error = xfs_refcount_get_rec(cur, &irec, &found_rec);270 if (error)271 goto out_error;272 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {273 xfs_btree_mark_sick(cur);274 error = -EFSCORRUPTED;275 goto out_error;276 }277 trace_xfs_refcount_delete(cur, &irec);278 error = xfs_btree_delete(cur, i);279 if (XFS_IS_CORRUPT(cur->bc_mp, *i != 1)) {280 xfs_btree_mark_sick(cur);281 error = -EFSCORRUPTED;282 goto out_error;283 }284 if (error)285 goto out_error;286 error = xfs_refcount_lookup_ge(cur, irec.rc_domain, irec.rc_startblock,287 &found_rec);288out_error:289 if (error)290 trace_xfs_refcount_delete_error(cur, error, _RET_IP_);291 return error;292}293 294/*295 * Adjusting the Reference Count296 *297 * As stated elsewhere, the reference count btree (refcbt) stores298 * >1 reference counts for extents of physical blocks. In this299 * operation, we're either raising or lowering the reference count of300 * some subrange stored in the tree:301 *302 * <------ adjustment range ------>303 * ----+ +---+-----+ +--+--------+---------304 * 2 | | 3 | 4 | |17| 55 | 10305 * ----+ +---+-----+ +--+--------+---------306 * X axis is physical blocks number;307 * reference counts are the numbers inside the rectangles308 *309 * The first thing we need to do is to ensure that there are no310 * refcount extents crossing either boundary of the range to be311 * adjusted. For any extent that does cross a boundary, split it into312 * two extents so that we can increment the refcount of one of the313 * pieces later:314 *315 * <------ adjustment range ------>316 * ----+ +---+-----+ +--+--------+----+----317 * 2 | | 3 | 2 | |17| 55 | 10 | 10318 * ----+ +---+-----+ +--+--------+----+----319 *320 * For this next step, let's assume that all the physical blocks in321 * the adjustment range are mapped to a file and are therefore in use322 * at least once. Therefore, we can infer that any gap in the323 * refcount tree within the adjustment range represents a physical324 * extent with refcount == 1:325 *326 * <------ adjustment range ------>327 * ----+---+---+-----+-+--+--------+----+----328 * 2 |"1"| 3 | 2 |1|17| 55 | 10 | 10329 * ----+---+---+-----+-+--+--------+----+----330 * ^331 *332 * For each extent that falls within the interval range, figure out333 * which extent is to the left or the right of that extent. Now we334 * have a left, current, and right extent. If the new reference count335 * of the center extent enables us to merge left, center, and right336 * into one record covering all three, do so. If the center extent is337 * at the left end of the range, abuts the left extent, and its new338 * reference count matches the left extent's record, then merge them.339 * If the center extent is at the right end of the range, abuts the340 * right extent, and the reference counts match, merge those. In the341 * example, we can left merge (assuming an increment operation):342 *343 * <------ adjustment range ------>344 * --------+---+-----+-+--+--------+----+----345 * 2 | 3 | 2 |1|17| 55 | 10 | 10346 * --------+---+-----+-+--+--------+----+----347 * ^348 *349 * For all other extents within the range, adjust the reference count350 * or delete it if the refcount falls below 2. If we were351 * incrementing, the end result looks like this:352 *353 * <------ adjustment range ------>354 * --------+---+-----+-+--+--------+----+----355 * 2 | 4 | 3 |2|18| 56 | 11 | 10356 * --------+---+-----+-+--+--------+----+----357 *358 * The result of a decrement operation looks as such:359 *360 * <------ adjustment range ------>361 * ----+ +---+ +--+--------+----+----362 * 2 | | 2 | |16| 54 | 9 | 10363 * ----+ +---+ +--+--------+----+----364 * DDDD 111111DD365 *366 * The blocks marked "D" are freed; the blocks marked "1" are only367 * referenced once and therefore the record is removed from the368 * refcount btree.369 */370 371/* Next block after this extent. */372static inline xfs_agblock_t373xfs_refc_next(374 struct xfs_refcount_irec *rc)375{376 return rc->rc_startblock + rc->rc_blockcount;377}378 379/*380 * Split a refcount extent that crosses agbno.381 */382STATIC int383xfs_refcount_split_extent(384 struct xfs_btree_cur *cur,385 enum xfs_refc_domain domain,386 xfs_agblock_t agbno,387 bool *shape_changed)388{389 struct xfs_refcount_irec rcext, tmp;390 int found_rec;391 int error;392 393 *shape_changed = false;394 error = xfs_refcount_lookup_le(cur, domain, agbno, &found_rec);395 if (error)396 goto out_error;397 if (!found_rec)398 return 0;399 400 error = xfs_refcount_get_rec(cur, &rcext, &found_rec);401 if (error)402 goto out_error;403 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {404 xfs_btree_mark_sick(cur);405 error = -EFSCORRUPTED;406 goto out_error;407 }408 if (rcext.rc_domain != domain)409 return 0;410 if (rcext.rc_startblock == agbno || xfs_refc_next(&rcext) <= agbno)411 return 0;412 413 *shape_changed = true;414 trace_xfs_refcount_split_extent(cur, &rcext, agbno);415 416 /* Establish the right extent. */417 tmp = rcext;418 tmp.rc_startblock = agbno;419 tmp.rc_blockcount -= (agbno - rcext.rc_startblock);420 error = xfs_refcount_update(cur, &tmp);421 if (error)422 goto out_error;423 424 /* Insert the left extent. */425 tmp = rcext;426 tmp.rc_blockcount = agbno - rcext.rc_startblock;427 error = xfs_refcount_insert(cur, &tmp, &found_rec);428 if (error)429 goto out_error;430 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {431 xfs_btree_mark_sick(cur);432 error = -EFSCORRUPTED;433 goto out_error;434 }435 return error;436 437out_error:438 trace_xfs_refcount_split_extent_error(cur, error, _RET_IP_);439 return error;440}441 442/*443 * Merge the left, center, and right extents.444 */445STATIC int446xfs_refcount_merge_center_extents(447 struct xfs_btree_cur *cur,448 struct xfs_refcount_irec *left,449 struct xfs_refcount_irec *center,450 struct xfs_refcount_irec *right,451 unsigned long long extlen,452 xfs_extlen_t *aglen)453{454 int error;455 int found_rec;456 457 trace_xfs_refcount_merge_center_extents(cur, left, center, right);458 459 ASSERT(left->rc_domain == center->rc_domain);460 ASSERT(right->rc_domain == center->rc_domain);461 462 /*463 * Make sure the center and right extents are not in the btree.464 * If the center extent was synthesized, the first delete call465 * removes the right extent and we skip the second deletion.466 * If center and right were in the btree, then the first delete467 * call removes the center and the second one removes the right468 * extent.469 */470 error = xfs_refcount_lookup_ge(cur, center->rc_domain,471 center->rc_startblock, &found_rec);472 if (error)473 goto out_error;474 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {475 xfs_btree_mark_sick(cur);476 error = -EFSCORRUPTED;477 goto out_error;478 }479 480 error = xfs_refcount_delete(cur, &found_rec);481 if (error)482 goto out_error;483 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {484 xfs_btree_mark_sick(cur);485 error = -EFSCORRUPTED;486 goto out_error;487 }488 489 if (center->rc_refcount > 1) {490 error = xfs_refcount_delete(cur, &found_rec);491 if (error)492 goto out_error;493 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {494 xfs_btree_mark_sick(cur);495 error = -EFSCORRUPTED;496 goto out_error;497 }498 }499 500 /* Enlarge the left extent. */501 error = xfs_refcount_lookup_le(cur, left->rc_domain,502 left->rc_startblock, &found_rec);503 if (error)504 goto out_error;505 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {506 xfs_btree_mark_sick(cur);507 error = -EFSCORRUPTED;508 goto out_error;509 }510 511 left->rc_blockcount = extlen;512 error = xfs_refcount_update(cur, left);513 if (error)514 goto out_error;515 516 *aglen = 0;517 return error;518 519out_error:520 trace_xfs_refcount_merge_center_extents_error(cur, error, _RET_IP_);521 return error;522}523 524/*525 * Merge with the left extent.526 */527STATIC int528xfs_refcount_merge_left_extent(529 struct xfs_btree_cur *cur,530 struct xfs_refcount_irec *left,531 struct xfs_refcount_irec *cleft,532 xfs_agblock_t *agbno,533 xfs_extlen_t *aglen)534{535 int error;536 int found_rec;537 538 trace_xfs_refcount_merge_left_extent(cur, left, cleft);539 540 ASSERT(left->rc_domain == cleft->rc_domain);541 542 /* If the extent at agbno (cleft) wasn't synthesized, remove it. */543 if (cleft->rc_refcount > 1) {544 error = xfs_refcount_lookup_le(cur, cleft->rc_domain,545 cleft->rc_startblock, &found_rec);546 if (error)547 goto out_error;548 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {549 xfs_btree_mark_sick(cur);550 error = -EFSCORRUPTED;551 goto out_error;552 }553 554 error = xfs_refcount_delete(cur, &found_rec);555 if (error)556 goto out_error;557 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {558 xfs_btree_mark_sick(cur);559 error = -EFSCORRUPTED;560 goto out_error;561 }562 }563 564 /* Enlarge the left extent. */565 error = xfs_refcount_lookup_le(cur, left->rc_domain,566 left->rc_startblock, &found_rec);567 if (error)568 goto out_error;569 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {570 xfs_btree_mark_sick(cur);571 error = -EFSCORRUPTED;572 goto out_error;573 }574 575 left->rc_blockcount += cleft->rc_blockcount;576 error = xfs_refcount_update(cur, left);577 if (error)578 goto out_error;579 580 *agbno += cleft->rc_blockcount;581 *aglen -= cleft->rc_blockcount;582 return error;583 584out_error:585 trace_xfs_refcount_merge_left_extent_error(cur, error, _RET_IP_);586 return error;587}588 589/*590 * Merge with the right extent.591 */592STATIC int593xfs_refcount_merge_right_extent(594 struct xfs_btree_cur *cur,595 struct xfs_refcount_irec *right,596 struct xfs_refcount_irec *cright,597 xfs_extlen_t *aglen)598{599 int error;600 int found_rec;601 602 trace_xfs_refcount_merge_right_extent(cur, cright, right);603 604 ASSERT(right->rc_domain == cright->rc_domain);605 606 /*607 * If the extent ending at agbno+aglen (cright) wasn't synthesized,608 * remove it.609 */610 if (cright->rc_refcount > 1) {611 error = xfs_refcount_lookup_le(cur, cright->rc_domain,612 cright->rc_startblock, &found_rec);613 if (error)614 goto out_error;615 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {616 xfs_btree_mark_sick(cur);617 error = -EFSCORRUPTED;618 goto out_error;619 }620 621 error = xfs_refcount_delete(cur, &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 }630 631 /* Enlarge the right extent. */632 error = xfs_refcount_lookup_le(cur, right->rc_domain,633 right->rc_startblock, &found_rec);634 if (error)635 goto out_error;636 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {637 xfs_btree_mark_sick(cur);638 error = -EFSCORRUPTED;639 goto out_error;640 }641 642 right->rc_startblock -= cright->rc_blockcount;643 right->rc_blockcount += cright->rc_blockcount;644 error = xfs_refcount_update(cur, right);645 if (error)646 goto out_error;647 648 *aglen -= cright->rc_blockcount;649 return error;650 651out_error:652 trace_xfs_refcount_merge_right_extent_error(cur, error, _RET_IP_);653 return error;654}655 656/*657 * Find the left extent and the one after it (cleft). This function assumes658 * that we've already split any extent crossing agbno.659 */660STATIC int661xfs_refcount_find_left_extents(662 struct xfs_btree_cur *cur,663 struct xfs_refcount_irec *left,664 struct xfs_refcount_irec *cleft,665 enum xfs_refc_domain domain,666 xfs_agblock_t agbno,667 xfs_extlen_t aglen)668{669 struct xfs_refcount_irec tmp;670 int error;671 int found_rec;672 673 left->rc_startblock = cleft->rc_startblock = NULLAGBLOCK;674 error = xfs_refcount_lookup_le(cur, domain, agbno - 1, &found_rec);675 if (error)676 goto out_error;677 if (!found_rec)678 return 0;679 680 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);681 if (error)682 goto out_error;683 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {684 xfs_btree_mark_sick(cur);685 error = -EFSCORRUPTED;686 goto out_error;687 }688 689 if (tmp.rc_domain != domain)690 return 0;691 if (xfs_refc_next(&tmp) != agbno)692 return 0;693 /* We have a left extent; retrieve (or invent) the next right one */694 *left = tmp;695 696 error = xfs_btree_increment(cur, 0, &found_rec);697 if (error)698 goto out_error;699 if (found_rec) {700 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);701 if (error)702 goto out_error;703 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {704 xfs_btree_mark_sick(cur);705 error = -EFSCORRUPTED;706 goto out_error;707 }708 709 if (tmp.rc_domain != domain)710 goto not_found;711 712 /* if tmp starts at the end of our range, just use that */713 if (tmp.rc_startblock == agbno)714 *cleft = tmp;715 else {716 /*717 * There's a gap in the refcntbt at the start of the718 * range we're interested in (refcount == 1) so719 * synthesize the implied extent and pass it back.720 * We assume here that the agbno/aglen range was721 * passed in from a data fork extent mapping and722 * therefore is allocated to exactly one owner.723 */724 cleft->rc_startblock = agbno;725 cleft->rc_blockcount = min(aglen,726 tmp.rc_startblock - agbno);727 cleft->rc_refcount = 1;728 cleft->rc_domain = domain;729 }730 } else {731not_found:732 /*733 * No extents, so pretend that there's one covering the whole734 * range.735 */736 cleft->rc_startblock = agbno;737 cleft->rc_blockcount = aglen;738 cleft->rc_refcount = 1;739 cleft->rc_domain = domain;740 }741 trace_xfs_refcount_find_left_extent(cur, left, cleft, agbno);742 return error;743 744out_error:745 trace_xfs_refcount_find_left_extent_error(cur, error, _RET_IP_);746 return error;747}748 749/*750 * Find the right extent and the one before it (cright). This function751 * assumes that we've already split any extents crossing agbno + aglen.752 */753STATIC int754xfs_refcount_find_right_extents(755 struct xfs_btree_cur *cur,756 struct xfs_refcount_irec *right,757 struct xfs_refcount_irec *cright,758 enum xfs_refc_domain domain,759 xfs_agblock_t agbno,760 xfs_extlen_t aglen)761{762 struct xfs_refcount_irec tmp;763 int error;764 int found_rec;765 766 right->rc_startblock = cright->rc_startblock = NULLAGBLOCK;767 error = xfs_refcount_lookup_ge(cur, domain, agbno + aglen, &found_rec);768 if (error)769 goto out_error;770 if (!found_rec)771 return 0;772 773 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);774 if (error)775 goto out_error;776 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {777 xfs_btree_mark_sick(cur);778 error = -EFSCORRUPTED;779 goto out_error;780 }781 782 if (tmp.rc_domain != domain)783 return 0;784 if (tmp.rc_startblock != agbno + aglen)785 return 0;786 /* We have a right extent; retrieve (or invent) the next left one */787 *right = tmp;788 789 error = xfs_btree_decrement(cur, 0, &found_rec);790 if (error)791 goto out_error;792 if (found_rec) {793 error = xfs_refcount_get_rec(cur, &tmp, &found_rec);794 if (error)795 goto out_error;796 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {797 xfs_btree_mark_sick(cur);798 error = -EFSCORRUPTED;799 goto out_error;800 }801 802 if (tmp.rc_domain != domain)803 goto not_found;804 805 /* if tmp ends at the end of our range, just use that */806 if (xfs_refc_next(&tmp) == agbno + aglen)807 *cright = tmp;808 else {809 /*810 * There's a gap in the refcntbt at the end of the811 * range we're interested in (refcount == 1) so812 * create the implied extent and pass it back.813 * We assume here that the agbno/aglen range was814 * passed in from a data fork extent mapping and815 * therefore is allocated to exactly one owner.816 */817 cright->rc_startblock = max(agbno, xfs_refc_next(&tmp));818 cright->rc_blockcount = right->rc_startblock -819 cright->rc_startblock;820 cright->rc_refcount = 1;821 cright->rc_domain = domain;822 }823 } else {824not_found:825 /*826 * No extents, so pretend that there's one covering the whole827 * range.828 */829 cright->rc_startblock = agbno;830 cright->rc_blockcount = aglen;831 cright->rc_refcount = 1;832 cright->rc_domain = domain;833 }834 trace_xfs_refcount_find_right_extent(cur, cright, right,835 agbno + aglen);836 return error;837 838out_error:839 trace_xfs_refcount_find_right_extent_error(cur, error, _RET_IP_);840 return error;841}842 843/* Is this extent valid? */844static inline bool845xfs_refc_valid(846 const struct xfs_refcount_irec *rc)847{848 return rc->rc_startblock != NULLAGBLOCK;849}850 851static inline xfs_nlink_t852xfs_refc_merge_refcount(853 const struct xfs_refcount_irec *irec,854 enum xfs_refc_adjust_op adjust)855{856 /* Once a record hits MAXREFCOUNT, it is pinned there forever */857 if (irec->rc_refcount == MAXREFCOUNT)858 return MAXREFCOUNT;859 return irec->rc_refcount + adjust;860}861 862static inline bool863xfs_refc_want_merge_center(864 const struct xfs_refcount_irec *left,865 const struct xfs_refcount_irec *cleft,866 const struct xfs_refcount_irec *cright,867 const struct xfs_refcount_irec *right,868 bool cleft_is_cright,869 enum xfs_refc_adjust_op adjust,870 unsigned long long *ulenp)871{872 unsigned long long ulen = left->rc_blockcount;873 xfs_nlink_t new_refcount;874 875 /*876 * To merge with a center record, both shoulder records must be877 * adjacent to the record we want to adjust. This is only true if878 * find_left and find_right made all four records valid.879 */880 if (!xfs_refc_valid(left) || !xfs_refc_valid(right) ||881 !xfs_refc_valid(cleft) || !xfs_refc_valid(cright))882 return false;883 884 /* There must only be one record for the entire range. */885 if (!cleft_is_cright)886 return false;887 888 /* The shoulder record refcounts must match the new refcount. */889 new_refcount = xfs_refc_merge_refcount(cleft, adjust);890 if (left->rc_refcount != new_refcount)891 return false;892 if (right->rc_refcount != new_refcount)893 return false;894 895 /*896 * The new record cannot exceed the max length. ulen is a ULL as the897 * individual record block counts can be up to (u32 - 1) in length898 * hence we need to catch u32 addition overflows here.899 */900 ulen += cleft->rc_blockcount + right->rc_blockcount;901 if (ulen >= MAXREFCEXTLEN)902 return false;903 904 *ulenp = ulen;905 return true;906}907 908static inline bool909xfs_refc_want_merge_left(910 const struct xfs_refcount_irec *left,911 const struct xfs_refcount_irec *cleft,912 enum xfs_refc_adjust_op adjust)913{914 unsigned long long ulen = left->rc_blockcount;915 xfs_nlink_t new_refcount;916 917 /*918 * For a left merge, the left shoulder record must be adjacent to the919 * start of the range. If this is true, find_left made left and cleft920 * contain valid contents.921 */922 if (!xfs_refc_valid(left) || !xfs_refc_valid(cleft))923 return false;924 925 /* Left shoulder record refcount must match the new refcount. */926 new_refcount = xfs_refc_merge_refcount(cleft, adjust);927 if (left->rc_refcount != new_refcount)928 return false;929 930 /*931 * The new record cannot exceed the max length. ulen is a ULL as the932 * individual record block counts can be up to (u32 - 1) in length933 * hence we need to catch u32 addition overflows here.934 */935 ulen += cleft->rc_blockcount;936 if (ulen >= MAXREFCEXTLEN)937 return false;938 939 return true;940}941 942static inline bool943xfs_refc_want_merge_right(944 const struct xfs_refcount_irec *cright,945 const struct xfs_refcount_irec *right,946 enum xfs_refc_adjust_op adjust)947{948 unsigned long long ulen = right->rc_blockcount;949 xfs_nlink_t new_refcount;950 951 /*952 * For a right merge, the right shoulder record must be adjacent to the953 * end of the range. If this is true, find_right made cright and right954 * contain valid contents.955 */956 if (!xfs_refc_valid(right) || !xfs_refc_valid(cright))957 return false;958 959 /* Right shoulder record refcount must match the new refcount. */960 new_refcount = xfs_refc_merge_refcount(cright, adjust);961 if (right->rc_refcount != new_refcount)962 return false;963 964 /*965 * The new record cannot exceed the max length. ulen is a ULL as the966 * individual record block counts can be up to (u32 - 1) in length967 * hence we need to catch u32 addition overflows here.968 */969 ulen += cright->rc_blockcount;970 if (ulen >= MAXREFCEXTLEN)971 return false;972 973 return true;974}975 976/*977 * Try to merge with any extents on the boundaries of the adjustment range.978 */979STATIC int980xfs_refcount_merge_extents(981 struct xfs_btree_cur *cur,982 enum xfs_refc_domain domain,983 xfs_agblock_t *agbno,984 xfs_extlen_t *aglen,985 enum xfs_refc_adjust_op adjust,986 bool *shape_changed)987{988 struct xfs_refcount_irec left = {0}, cleft = {0};989 struct xfs_refcount_irec cright = {0}, right = {0};990 int error;991 unsigned long long ulen;992 bool cequal;993 994 *shape_changed = false;995 /*996 * Find the extent just below agbno [left], just above agbno [cleft],997 * just below (agbno + aglen) [cright], and just above (agbno + aglen)998 * [right].999 */1000 error = xfs_refcount_find_left_extents(cur, &left, &cleft, domain,1001 *agbno, *aglen);1002 if (error)1003 return error;1004 error = xfs_refcount_find_right_extents(cur, &right, &cright, domain,1005 *agbno, *aglen);1006 if (error)1007 return error;1008 1009 /* No left or right extent to merge; exit. */1010 if (!xfs_refc_valid(&left) && !xfs_refc_valid(&right))1011 return 0;1012 1013 cequal = (cleft.rc_startblock == cright.rc_startblock) &&1014 (cleft.rc_blockcount == cright.rc_blockcount);1015 1016 /* Try to merge left, cleft, and right. cleft must == cright. */1017 if (xfs_refc_want_merge_center(&left, &cleft, &cright, &right, cequal,1018 adjust, &ulen)) {1019 *shape_changed = true;1020 return xfs_refcount_merge_center_extents(cur, &left, &cleft,1021 &right, ulen, aglen);1022 }1023 1024 /* Try to merge left and cleft. */1025 if (xfs_refc_want_merge_left(&left, &cleft, adjust)) {1026 *shape_changed = true;1027 error = xfs_refcount_merge_left_extent(cur, &left, &cleft,1028 agbno, aglen);1029 if (error)1030 return error;1031 1032 /*1033 * If we just merged left + cleft and cleft == cright,1034 * we no longer have a cright to merge with right. We're done.1035 */1036 if (cequal)1037 return 0;1038 }1039 1040 /* Try to merge cright and right. */1041 if (xfs_refc_want_merge_right(&cright, &right, adjust)) {1042 *shape_changed = true;1043 return xfs_refcount_merge_right_extent(cur, &right, &cright,1044 aglen);1045 }1046 1047 return 0;1048}1049 1050/*1051 * XXX: This is a pretty hand-wavy estimate. The penalty for guessing1052 * true incorrectly is a shutdown FS; the penalty for guessing false1053 * incorrectly is more transaction rolls than might be necessary.1054 * Be conservative here.1055 */1056static bool1057xfs_refcount_still_have_space(1058 struct xfs_btree_cur *cur)1059{1060 unsigned long overhead;1061 1062 /*1063 * Worst case estimate: full splits of the free space and rmap btrees1064 * to handle each of the shape changes to the refcount btree.1065 */1066 overhead = xfs_allocfree_block_count(cur->bc_mp,1067 cur->bc_refc.shape_changes);1068 overhead += cur->bc_mp->m_refc_maxlevels;1069 overhead *= cur->bc_mp->m_sb.sb_blocksize;1070 1071 /*1072 * Only allow 2 refcount extent updates per transaction if the1073 * refcount continue update "error" has been injected.1074 */1075 if (cur->bc_refc.nr_ops > 2 &&1076 XFS_TEST_ERROR(false, cur->bc_mp,1077 XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE))1078 return false;1079 1080 if (cur->bc_refc.nr_ops == 0)1081 return true;1082 else if (overhead > cur->bc_tp->t_log_res)1083 return false;1084 return cur->bc_tp->t_log_res - overhead >1085 cur->bc_refc.nr_ops * XFS_REFCOUNT_ITEM_OVERHEAD;1086}1087 1088/*1089 * Adjust the refcounts of middle extents. At this point we should have1090 * split extents that crossed the adjustment range; merged with adjacent1091 * extents; and updated agbno/aglen to reflect the merges. Therefore,1092 * all we have to do is update the extents inside [agbno, agbno + aglen].1093 */1094STATIC int1095xfs_refcount_adjust_extents(1096 struct xfs_btree_cur *cur,1097 xfs_agblock_t *agbno,1098 xfs_extlen_t *aglen,1099 enum xfs_refc_adjust_op adj)1100{1101 struct xfs_refcount_irec ext, tmp;1102 int error;1103 int found_rec, found_tmp;1104 xfs_fsblock_t fsbno;1105 1106 /* Merging did all the work already. */1107 if (*aglen == 0)1108 return 0;1109 1110 error = xfs_refcount_lookup_ge(cur, XFS_REFC_DOMAIN_SHARED, *agbno,1111 &found_rec);1112 if (error)1113 goto out_error;1114 1115 while (*aglen > 0 && xfs_refcount_still_have_space(cur)) {1116 error = xfs_refcount_get_rec(cur, &ext, &found_rec);1117 if (error)1118 goto out_error;1119 if (!found_rec || ext.rc_domain != XFS_REFC_DOMAIN_SHARED) {1120 ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks;1121 ext.rc_blockcount = 0;1122 ext.rc_refcount = 0;1123 ext.rc_domain = XFS_REFC_DOMAIN_SHARED;1124 }1125 1126 /*1127 * Deal with a hole in the refcount tree; if a file maps to1128 * these blocks and there's no refcountbt record, pretend that1129 * there is one with refcount == 1.1130 */1131 if (ext.rc_startblock != *agbno) {1132 tmp.rc_startblock = *agbno;1133 tmp.rc_blockcount = min(*aglen,1134 ext.rc_startblock - *agbno);1135 tmp.rc_refcount = 1 + adj;1136 tmp.rc_domain = XFS_REFC_DOMAIN_SHARED;1137 1138 trace_xfs_refcount_modify_extent(cur, &tmp);1139 1140 /*1141 * Either cover the hole (increment) or1142 * delete the range (decrement).1143 */1144 cur->bc_refc.nr_ops++;1145 if (tmp.rc_refcount) {1146 error = xfs_refcount_insert(cur, &tmp,1147 &found_tmp);1148 if (error)1149 goto out_error;1150 if (XFS_IS_CORRUPT(cur->bc_mp,1151 found_tmp != 1)) {1152 xfs_btree_mark_sick(cur);1153 error = -EFSCORRUPTED;1154 goto out_error;1155 }1156 } else {1157 fsbno = XFS_AGB_TO_FSB(cur->bc_mp,1158 cur->bc_ag.pag->pag_agno,1159 tmp.rc_startblock);1160 error = xfs_free_extent_later(cur->bc_tp, fsbno,1161 tmp.rc_blockcount, NULL,1162 XFS_AG_RESV_NONE, 0);1163 if (error)1164 goto out_error;1165 }1166 1167 (*agbno) += tmp.rc_blockcount;1168 (*aglen) -= tmp.rc_blockcount;1169 1170 /* Stop if there's nothing left to modify */1171 if (*aglen == 0 || !xfs_refcount_still_have_space(cur))1172 break;1173 1174 /* Move the cursor to the start of ext. */1175 error = xfs_refcount_lookup_ge(cur,1176 XFS_REFC_DOMAIN_SHARED, *agbno,1177 &found_rec);1178 if (error)1179 goto out_error;1180 }1181 1182 /*1183 * A previous step trimmed agbno/aglen such that the end of the1184 * range would not be in the middle of the record. If this is1185 * no longer the case, something is seriously wrong with the1186 * btree. Make sure we never feed the synthesized record into1187 * the processing loop below.1188 */1189 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount == 0) ||1190 XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount > *aglen)) {1191 xfs_btree_mark_sick(cur);1192 error = -EFSCORRUPTED;1193 goto out_error;1194 }1195 1196 /*1197 * Adjust the reference count and either update the tree1198 * (incr) or free the blocks (decr).1199 */1200 if (ext.rc_refcount == MAXREFCOUNT)1201 goto skip;1202 ext.rc_refcount += adj;1203 trace_xfs_refcount_modify_extent(cur, &ext);1204 cur->bc_refc.nr_ops++;1205 if (ext.rc_refcount > 1) {1206 error = xfs_refcount_update(cur, &ext);1207 if (error)1208 goto out_error;1209 } else if (ext.rc_refcount == 1) {1210 error = xfs_refcount_delete(cur, &found_rec);1211 if (error)1212 goto out_error;1213 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {1214 xfs_btree_mark_sick(cur);1215 error = -EFSCORRUPTED;1216 goto out_error;1217 }1218 goto advloop;1219 } else {1220 fsbno = XFS_AGB_TO_FSB(cur->bc_mp,1221 cur->bc_ag.pag->pag_agno,1222 ext.rc_startblock);1223 error = xfs_free_extent_later(cur->bc_tp, fsbno,1224 ext.rc_blockcount, NULL,1225 XFS_AG_RESV_NONE, 0);1226 if (error)1227 goto out_error;1228 }1229 1230skip:1231 error = xfs_btree_increment(cur, 0, &found_rec);1232 if (error)1233 goto out_error;1234 1235advloop:1236 (*agbno) += ext.rc_blockcount;1237 (*aglen) -= ext.rc_blockcount;1238 }1239 1240 return error;1241out_error:1242 trace_xfs_refcount_modify_extent_error(cur, error, _RET_IP_);1243 return error;1244}1245 1246/* Adjust the reference count of a range of AG blocks. */1247STATIC int1248xfs_refcount_adjust(1249 struct xfs_btree_cur *cur,1250 xfs_agblock_t *agbno,1251 xfs_extlen_t *aglen,1252 enum xfs_refc_adjust_op adj)1253{1254 bool shape_changed;1255 int shape_changes = 0;1256 int error;1257 1258 if (adj == XFS_REFCOUNT_ADJUST_INCREASE)1259 trace_xfs_refcount_increase(cur, *agbno, *aglen);1260 else1261 trace_xfs_refcount_decrease(cur, *agbno, *aglen);1262 1263 /*1264 * Ensure that no rcextents cross the boundary of the adjustment range.1265 */1266 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_SHARED,1267 *agbno, &shape_changed);1268 if (error)1269 goto out_error;1270 if (shape_changed)1271 shape_changes++;1272 1273 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_SHARED,1274 *agbno + *aglen, &shape_changed);1275 if (error)1276 goto out_error;1277 if (shape_changed)1278 shape_changes++;1279 1280 /*1281 * Try to merge with the left or right extents of the range.1282 */1283 error = xfs_refcount_merge_extents(cur, XFS_REFC_DOMAIN_SHARED,1284 agbno, aglen, adj, &shape_changed);1285 if (error)1286 goto out_error;1287 if (shape_changed)1288 shape_changes++;1289 if (shape_changes)1290 cur->bc_refc.shape_changes++;1291 1292 /* Now that we've taken care of the ends, adjust the middle extents */1293 error = xfs_refcount_adjust_extents(cur, agbno, aglen, adj);1294 if (error)1295 goto out_error;1296 1297 return 0;1298 1299out_error:1300 trace_xfs_refcount_adjust_error(cur, error, _RET_IP_);1301 return error;1302}1303 1304/*1305 * Set up a continuation a deferred refcount operation by updating the intent.1306 * Checks to make sure we're not going to run off the end of the AG.1307 */1308static inline int1309xfs_refcount_continue_op(1310 struct xfs_btree_cur *cur,1311 struct xfs_refcount_intent *ri,1312 xfs_agblock_t new_agbno)1313{1314 struct xfs_mount *mp = cur->bc_mp;1315 struct xfs_perag *pag = cur->bc_ag.pag;1316 1317 if (XFS_IS_CORRUPT(mp, !xfs_verify_agbext(pag, new_agbno,1318 ri->ri_blockcount))) {1319 xfs_btree_mark_sick(cur);1320 return -EFSCORRUPTED;1321 }1322 1323 ri->ri_startblock = XFS_AGB_TO_FSB(mp, pag->pag_agno, new_agbno);1324 1325 ASSERT(xfs_verify_fsbext(mp, ri->ri_startblock, ri->ri_blockcount));1326 ASSERT(pag->pag_agno == XFS_FSB_TO_AGNO(mp, ri->ri_startblock));1327 1328 return 0;1329}1330 1331/*1332 * Process one of the deferred refcount operations. We pass back the1333 * btree cursor to maintain our lock on the btree between calls.1334 * This saves time and eliminates a buffer deadlock between the1335 * superblock and the AGF because we'll always grab them in the same1336 * order.1337 */1338int1339xfs_refcount_finish_one(1340 struct xfs_trans *tp,1341 struct xfs_refcount_intent *ri,1342 struct xfs_btree_cur **pcur)1343{1344 struct xfs_mount *mp = tp->t_mountp;1345 struct xfs_btree_cur *rcur = *pcur;1346 struct xfs_buf *agbp = NULL;1347 int error = 0;1348 xfs_agblock_t bno;1349 unsigned long nr_ops = 0;1350 int shape_changes = 0;1351 1352 bno = XFS_FSB_TO_AGBNO(mp, ri->ri_startblock);1353 1354 trace_xfs_refcount_deferred(mp, ri);1355 1356 if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_REFCOUNT_FINISH_ONE))1357 return -EIO;1358 1359 /*1360 * If we haven't gotten a cursor or the cursor AG doesn't match1361 * the startblock, get one now.1362 */1363 if (rcur != NULL && rcur->bc_ag.pag != ri->ri_pag) {1364 nr_ops = rcur->bc_refc.nr_ops;1365 shape_changes = rcur->bc_refc.shape_changes;1366 xfs_btree_del_cursor(rcur, 0);1367 rcur = NULL;1368 *pcur = NULL;1369 }1370 if (rcur == NULL) {1371 error = xfs_alloc_read_agf(ri->ri_pag, tp,1372 XFS_ALLOC_FLAG_FREEING, &agbp);1373 if (error)1374 return error;1375 1376 *pcur = rcur = xfs_refcountbt_init_cursor(mp, tp, agbp,1377 ri->ri_pag);1378 rcur->bc_refc.nr_ops = nr_ops;1379 rcur->bc_refc.shape_changes = shape_changes;1380 }1381 1382 switch (ri->ri_type) {1383 case XFS_REFCOUNT_INCREASE:1384 error = xfs_refcount_adjust(rcur, &bno, &ri->ri_blockcount,1385 XFS_REFCOUNT_ADJUST_INCREASE);1386 if (error)1387 return error;1388 if (ri->ri_blockcount > 0)1389 error = xfs_refcount_continue_op(rcur, ri, bno);1390 break;1391 case XFS_REFCOUNT_DECREASE:1392 error = xfs_refcount_adjust(rcur, &bno, &ri->ri_blockcount,1393 XFS_REFCOUNT_ADJUST_DECREASE);1394 if (error)1395 return error;1396 if (ri->ri_blockcount > 0)1397 error = xfs_refcount_continue_op(rcur, ri, bno);1398 break;1399 case XFS_REFCOUNT_ALLOC_COW:1400 error = __xfs_refcount_cow_alloc(rcur, bno, ri->ri_blockcount);1401 if (error)1402 return error;1403 ri->ri_blockcount = 0;1404 break;1405 case XFS_REFCOUNT_FREE_COW:1406 error = __xfs_refcount_cow_free(rcur, bno, ri->ri_blockcount);1407 if (error)1408 return error;1409 ri->ri_blockcount = 0;1410 break;1411 default:1412 ASSERT(0);1413 return -EFSCORRUPTED;1414 }1415 if (!error && ri->ri_blockcount > 0)1416 trace_xfs_refcount_finish_one_leftover(mp, ri);1417 return error;1418}1419 1420/*1421 * Record a refcount intent for later processing.1422 */1423static void1424__xfs_refcount_add(1425 struct xfs_trans *tp,1426 enum xfs_refcount_intent_type type,1427 xfs_fsblock_t startblock,1428 xfs_extlen_t blockcount)1429{1430 struct xfs_refcount_intent *ri;1431 1432 ri = kmem_cache_alloc(xfs_refcount_intent_cache,1433 GFP_KERNEL | __GFP_NOFAIL);1434 INIT_LIST_HEAD(&ri->ri_list);1435 ri->ri_type = type;1436 ri->ri_startblock = startblock;1437 ri->ri_blockcount = blockcount;1438 1439 xfs_refcount_defer_add(tp, ri);1440}1441 1442/*1443 * Increase the reference count of the blocks backing a file's extent.1444 */1445void1446xfs_refcount_increase_extent(1447 struct xfs_trans *tp,1448 struct xfs_bmbt_irec *PREV)1449{1450 if (!xfs_has_reflink(tp->t_mountp))1451 return;1452 1453 __xfs_refcount_add(tp, XFS_REFCOUNT_INCREASE, PREV->br_startblock,1454 PREV->br_blockcount);1455}1456 1457/*1458 * Decrease the reference count of the blocks backing a file's extent.1459 */1460void1461xfs_refcount_decrease_extent(1462 struct xfs_trans *tp,1463 struct xfs_bmbt_irec *PREV)1464{1465 if (!xfs_has_reflink(tp->t_mountp))1466 return;1467 1468 __xfs_refcount_add(tp, XFS_REFCOUNT_DECREASE, PREV->br_startblock,1469 PREV->br_blockcount);1470}1471 1472/*1473 * Given an AG extent, find the lowest-numbered run of shared blocks1474 * within that range and return the range in fbno/flen. If1475 * find_end_of_shared is set, return the longest contiguous extent of1476 * shared blocks; if not, just return the first extent we find. If no1477 * shared blocks are found, fbno and flen will be set to NULLAGBLOCK1478 * and 0, respectively.1479 */1480int1481xfs_refcount_find_shared(1482 struct xfs_btree_cur *cur,1483 xfs_agblock_t agbno,1484 xfs_extlen_t aglen,1485 xfs_agblock_t *fbno,1486 xfs_extlen_t *flen,1487 bool find_end_of_shared)1488{1489 struct xfs_refcount_irec tmp;1490 int i;1491 int have;1492 int error;1493 1494 trace_xfs_refcount_find_shared(cur, agbno, aglen);1495 1496 /* By default, skip the whole range */1497 *fbno = NULLAGBLOCK;1498 *flen = 0;1499 1500 /* Try to find a refcount extent that crosses the start */1501 error = xfs_refcount_lookup_le(cur, XFS_REFC_DOMAIN_SHARED, agbno,1502 &have);1503 if (error)1504 goto out_error;1505 if (!have) {1506 /* No left extent, look at the next one */1507 error = xfs_btree_increment(cur, 0, &have);1508 if (error)1509 goto out_error;1510 if (!have)1511 goto done;1512 }1513 error = xfs_refcount_get_rec(cur, &tmp, &i);1514 if (error)1515 goto out_error;1516 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {1517 xfs_btree_mark_sick(cur);1518 error = -EFSCORRUPTED;1519 goto out_error;1520 }1521 if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED)1522 goto done;1523 1524 /* If the extent ends before the start, look at the next one */1525 if (tmp.rc_startblock + tmp.rc_blockcount <= agbno) {1526 error = xfs_btree_increment(cur, 0, &have);1527 if (error)1528 goto out_error;1529 if (!have)1530 goto done;1531 error = xfs_refcount_get_rec(cur, &tmp, &i);1532 if (error)1533 goto out_error;1534 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {1535 xfs_btree_mark_sick(cur);1536 error = -EFSCORRUPTED;1537 goto out_error;1538 }1539 if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED)1540 goto done;1541 }1542 1543 /* If the extent starts after the range we want, bail out */1544 if (tmp.rc_startblock >= agbno + aglen)1545 goto done;1546 1547 /* We found the start of a shared extent! */1548 if (tmp.rc_startblock < agbno) {1549 tmp.rc_blockcount -= (agbno - tmp.rc_startblock);1550 tmp.rc_startblock = agbno;1551 }1552 1553 *fbno = tmp.rc_startblock;1554 *flen = min(tmp.rc_blockcount, agbno + aglen - *fbno);1555 if (!find_end_of_shared)1556 goto done;1557 1558 /* Otherwise, find the end of this shared extent */1559 while (*fbno + *flen < agbno + aglen) {1560 error = xfs_btree_increment(cur, 0, &have);1561 if (error)1562 goto out_error;1563 if (!have)1564 break;1565 error = xfs_refcount_get_rec(cur, &tmp, &i);1566 if (error)1567 goto out_error;1568 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {1569 xfs_btree_mark_sick(cur);1570 error = -EFSCORRUPTED;1571 goto out_error;1572 }1573 if (tmp.rc_domain != XFS_REFC_DOMAIN_SHARED ||1574 tmp.rc_startblock >= agbno + aglen ||1575 tmp.rc_startblock != *fbno + *flen)1576 break;1577 *flen = min(*flen + tmp.rc_blockcount, agbno + aglen - *fbno);1578 }1579 1580done:1581 trace_xfs_refcount_find_shared_result(cur, *fbno, *flen);1582 1583out_error:1584 if (error)1585 trace_xfs_refcount_find_shared_error(cur, error, _RET_IP_);1586 return error;1587}1588 1589/*1590 * Recovering CoW Blocks After a Crash1591 *1592 * Due to the way that the copy on write mechanism works, there's a window of1593 * opportunity in which we can lose track of allocated blocks during a crash.1594 * Because CoW uses delayed allocation in the in-core CoW fork, writeback1595 * causes blocks to be allocated and stored in the CoW fork. The blocks are1596 * no longer in the free space btree but are not otherwise recorded anywhere1597 * until the write completes and the blocks are mapped into the file. A crash1598 * in between allocation and remapping results in the replacement blocks being1599 * lost. This situation is exacerbated by the CoW extent size hint because1600 * allocations can hang around for long time.1601 *1602 * However, there is a place where we can record these allocations before they1603 * become mappings -- the reference count btree. The btree does not record1604 * extents with refcount == 1, so we can record allocations with a refcount of1605 * 1. Blocks being used for CoW writeout cannot be shared, so there should be1606 * no conflict with shared block records. These mappings should be created1607 * when we allocate blocks to the CoW fork and deleted when they're removed1608 * from the CoW fork.1609 *1610 * Minor nit: records for in-progress CoW allocations and records for shared1611 * extents must never be merged, to preserve the property that (except for CoW1612 * allocations) there are no refcount btree entries with refcount == 1. The1613 * only time this could potentially happen is when unsharing a block that's1614 * adjacent to CoW allocations, so we must be careful to avoid this.1615 *1616 * At mount time we recover lost CoW allocations by searching the refcount1617 * btree for these refcount == 1 mappings. These represent CoW allocations1618 * that were in progress at the time the filesystem went down, so we can free1619 * them to get the space back.1620 *1621 * This mechanism is superior to creating EFIs for unmapped CoW extents for1622 * several reasons -- first, EFIs pin the tail of the log and would have to be1623 * periodically relogged to avoid filling up the log. Second, CoW completions1624 * will have to file an EFD and create new EFIs for whatever remains in the1625 * CoW fork; this partially takes care of (1) but extent-size reservations1626 * will have to periodically relog even if there's no writeout in progress.1627 * This can happen if the CoW extent size hint is set, which you really want.1628 * Third, EFIs cannot currently be automatically relogged into newer1629 * transactions to advance the log tail. Fourth, stuffing the log full of1630 * EFIs places an upper bound on the number of CoW allocations that can be1631 * held filesystem-wide at any given time. Recording them in the refcount1632 * btree doesn't require us to maintain any state in memory and doesn't pin1633 * the log.1634 */1635/*1636 * Adjust the refcounts of CoW allocations. These allocations are "magic"1637 * in that they're not referenced anywhere else in the filesystem, so we1638 * stash them in the refcount btree with a refcount of 1 until either file1639 * remapping (or CoW cancellation) happens.1640 */1641STATIC int1642xfs_refcount_adjust_cow_extents(1643 struct xfs_btree_cur *cur,1644 xfs_agblock_t agbno,1645 xfs_extlen_t aglen,1646 enum xfs_refc_adjust_op adj)1647{1648 struct xfs_refcount_irec ext, tmp;1649 int error;1650 int found_rec, found_tmp;1651 1652 if (aglen == 0)1653 return 0;1654 1655 /* Find any overlapping refcount records */1656 error = xfs_refcount_lookup_ge(cur, XFS_REFC_DOMAIN_COW, agbno,1657 &found_rec);1658 if (error)1659 goto out_error;1660 error = xfs_refcount_get_rec(cur, &ext, &found_rec);1661 if (error)1662 goto out_error;1663 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec &&1664 ext.rc_domain != XFS_REFC_DOMAIN_COW)) {1665 xfs_btree_mark_sick(cur);1666 error = -EFSCORRUPTED;1667 goto out_error;1668 }1669 if (!found_rec) {1670 ext.rc_startblock = cur->bc_mp->m_sb.sb_agblocks;1671 ext.rc_blockcount = 0;1672 ext.rc_refcount = 0;1673 ext.rc_domain = XFS_REFC_DOMAIN_COW;1674 }1675 1676 switch (adj) {1677 case XFS_REFCOUNT_ADJUST_COW_ALLOC:1678 /* Adding a CoW reservation, there should be nothing here. */1679 if (XFS_IS_CORRUPT(cur->bc_mp,1680 agbno + aglen > ext.rc_startblock)) {1681 xfs_btree_mark_sick(cur);1682 error = -EFSCORRUPTED;1683 goto out_error;1684 }1685 1686 tmp.rc_startblock = agbno;1687 tmp.rc_blockcount = aglen;1688 tmp.rc_refcount = 1;1689 tmp.rc_domain = XFS_REFC_DOMAIN_COW;1690 1691 trace_xfs_refcount_modify_extent(cur, &tmp);1692 1693 error = xfs_refcount_insert(cur, &tmp,1694 &found_tmp);1695 if (error)1696 goto out_error;1697 if (XFS_IS_CORRUPT(cur->bc_mp, found_tmp != 1)) {1698 xfs_btree_mark_sick(cur);1699 error = -EFSCORRUPTED;1700 goto out_error;1701 }1702 break;1703 case XFS_REFCOUNT_ADJUST_COW_FREE:1704 /* Removing a CoW reservation, there should be one extent. */1705 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_startblock != agbno)) {1706 xfs_btree_mark_sick(cur);1707 error = -EFSCORRUPTED;1708 goto out_error;1709 }1710 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_blockcount != aglen)) {1711 xfs_btree_mark_sick(cur);1712 error = -EFSCORRUPTED;1713 goto out_error;1714 }1715 if (XFS_IS_CORRUPT(cur->bc_mp, ext.rc_refcount != 1)) {1716 xfs_btree_mark_sick(cur);1717 error = -EFSCORRUPTED;1718 goto out_error;1719 }1720 1721 ext.rc_refcount = 0;1722 trace_xfs_refcount_modify_extent(cur, &ext);1723 error = xfs_refcount_delete(cur, &found_rec);1724 if (error)1725 goto out_error;1726 if (XFS_IS_CORRUPT(cur->bc_mp, found_rec != 1)) {1727 xfs_btree_mark_sick(cur);1728 error = -EFSCORRUPTED;1729 goto out_error;1730 }1731 break;1732 default:1733 ASSERT(0);1734 }1735 1736 return error;1737out_error:1738 trace_xfs_refcount_modify_extent_error(cur, error, _RET_IP_);1739 return error;1740}1741 1742/*1743 * Add or remove refcount btree entries for CoW reservations.1744 */1745STATIC int1746xfs_refcount_adjust_cow(1747 struct xfs_btree_cur *cur,1748 xfs_agblock_t agbno,1749 xfs_extlen_t aglen,1750 enum xfs_refc_adjust_op adj)1751{1752 bool shape_changed;1753 int error;1754 1755 /*1756 * Ensure that no rcextents cross the boundary of the adjustment range.1757 */1758 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_COW,1759 agbno, &shape_changed);1760 if (error)1761 goto out_error;1762 1763 error = xfs_refcount_split_extent(cur, XFS_REFC_DOMAIN_COW,1764 agbno + aglen, &shape_changed);1765 if (error)1766 goto out_error;1767 1768 /*1769 * Try to merge with the left or right extents of the range.1770 */1771 error = xfs_refcount_merge_extents(cur, XFS_REFC_DOMAIN_COW, &agbno,1772 &aglen, adj, &shape_changed);1773 if (error)1774 goto out_error;1775 1776 /* Now that we've taken care of the ends, adjust the middle extents */1777 error = xfs_refcount_adjust_cow_extents(cur, agbno, aglen, adj);1778 if (error)1779 goto out_error;1780 1781 return 0;1782 1783out_error:1784 trace_xfs_refcount_adjust_cow_error(cur, error, _RET_IP_);1785 return error;1786}1787 1788/*1789 * Record a CoW allocation in the refcount btree.1790 */1791STATIC int1792__xfs_refcount_cow_alloc(1793 struct xfs_btree_cur *rcur,1794 xfs_agblock_t agbno,1795 xfs_extlen_t aglen)1796{1797 trace_xfs_refcount_cow_increase(rcur, agbno, aglen);1798 1799 /* Add refcount btree reservation */1800 return xfs_refcount_adjust_cow(rcur, agbno, aglen,1801 XFS_REFCOUNT_ADJUST_COW_ALLOC);1802}1803 1804/*1805 * Remove a CoW allocation from the refcount btree.1806 */1807STATIC int1808__xfs_refcount_cow_free(1809 struct xfs_btree_cur *rcur,1810 xfs_agblock_t agbno,1811 xfs_extlen_t aglen)1812{1813 trace_xfs_refcount_cow_decrease(rcur, agbno, aglen);1814 1815 /* Remove refcount btree reservation */1816 return xfs_refcount_adjust_cow(rcur, agbno, aglen,1817 XFS_REFCOUNT_ADJUST_COW_FREE);1818}1819 1820/* Record a CoW staging extent in the refcount btree. */1821void1822xfs_refcount_alloc_cow_extent(1823 struct xfs_trans *tp,1824 xfs_fsblock_t fsb,1825 xfs_extlen_t len)1826{1827 struct xfs_mount *mp = tp->t_mountp;1828 1829 if (!xfs_has_reflink(mp))1830 return;1831 1832 __xfs_refcount_add(tp, XFS_REFCOUNT_ALLOC_COW, fsb, len);1833 1834 /* Add rmap entry */1835 xfs_rmap_alloc_extent(tp, XFS_FSB_TO_AGNO(mp, fsb),1836 XFS_FSB_TO_AGBNO(mp, fsb), len, XFS_RMAP_OWN_COW);1837}1838 1839/* Forget a CoW staging event in the refcount btree. */1840void1841xfs_refcount_free_cow_extent(1842 struct xfs_trans *tp,1843 xfs_fsblock_t fsb,1844 xfs_extlen_t len)1845{1846 struct xfs_mount *mp = tp->t_mountp;1847 1848 if (!xfs_has_reflink(mp))1849 return;1850 1851 /* Remove rmap entry */1852 xfs_rmap_free_extent(tp, XFS_FSB_TO_AGNO(mp, fsb),1853 XFS_FSB_TO_AGBNO(mp, fsb), len, XFS_RMAP_OWN_COW);1854 __xfs_refcount_add(tp, XFS_REFCOUNT_FREE_COW, fsb, len);1855}1856 1857struct xfs_refcount_recovery {1858 struct list_head rr_list;1859 struct xfs_refcount_irec rr_rrec;1860};1861 1862/* Stuff an extent on the recovery list. */1863STATIC int1864xfs_refcount_recover_extent(1865 struct xfs_btree_cur *cur,1866 const union xfs_btree_rec *rec,1867 void *priv)1868{1869 struct list_head *debris = priv;1870 struct xfs_refcount_recovery *rr;1871 1872 if (XFS_IS_CORRUPT(cur->bc_mp,1873 be32_to_cpu(rec->refc.rc_refcount) != 1)) {1874 xfs_btree_mark_sick(cur);1875 return -EFSCORRUPTED;1876 }1877 1878 rr = kmalloc(sizeof(struct xfs_refcount_recovery),1879 GFP_KERNEL | __GFP_NOFAIL);1880 INIT_LIST_HEAD(&rr->rr_list);1881 xfs_refcount_btrec_to_irec(rec, &rr->rr_rrec);1882 1883 if (xfs_refcount_check_irec(cur->bc_ag.pag, &rr->rr_rrec) != NULL ||1884 XFS_IS_CORRUPT(cur->bc_mp,1885 rr->rr_rrec.rc_domain != XFS_REFC_DOMAIN_COW)) {1886 xfs_btree_mark_sick(cur);1887 kfree(rr);1888 return -EFSCORRUPTED;1889 }1890 1891 list_add_tail(&rr->rr_list, debris);1892 return 0;1893}1894 1895/* Find and remove leftover CoW reservations. */1896int1897xfs_refcount_recover_cow_leftovers(1898 struct xfs_mount *mp,1899 struct xfs_perag *pag)1900{1901 struct xfs_trans *tp;1902 struct xfs_btree_cur *cur;1903 struct xfs_buf *agbp;1904 struct xfs_refcount_recovery *rr, *n;1905 struct list_head debris;1906 union xfs_btree_irec low = {1907 .rc.rc_domain = XFS_REFC_DOMAIN_COW,1908 };1909 union xfs_btree_irec high = {1910 .rc.rc_domain = XFS_REFC_DOMAIN_COW,1911 .rc.rc_startblock = -1U,1912 };1913 xfs_fsblock_t fsb;1914 int error;1915 1916 /* reflink filesystems mustn't have AGs larger than 2^31-1 blocks */1917 BUILD_BUG_ON(XFS_MAX_CRC_AG_BLOCKS >= XFS_REFC_COWFLAG);1918 if (mp->m_sb.sb_agblocks > XFS_MAX_CRC_AG_BLOCKS)1919 return -EOPNOTSUPP;1920 1921 INIT_LIST_HEAD(&debris);1922 1923 /*1924 * In this first part, we use an empty transaction to gather up1925 * all the leftover CoW extents so that we can subsequently1926 * delete them. The empty transaction is used to avoid1927 * a buffer lock deadlock if there happens to be a loop in the1928 * refcountbt because we're allowed to re-grab a buffer that is1929 * already attached to our transaction. When we're done1930 * recording the CoW debris we cancel the (empty) transaction1931 * and everything goes away cleanly.1932 */1933 error = xfs_trans_alloc_empty(mp, &tp);1934 if (error)1935 return error;1936 1937 error = xfs_alloc_read_agf(pag, tp, 0, &agbp);1938 if (error)1939 goto out_trans;1940 cur = xfs_refcountbt_init_cursor(mp, tp, agbp, pag);1941 1942 /* Find all the leftover CoW staging extents. */1943 error = xfs_btree_query_range(cur, &low, &high,1944 xfs_refcount_recover_extent, &debris);1945 xfs_btree_del_cursor(cur, error);1946 xfs_trans_brelse(tp, agbp);1947 xfs_trans_cancel(tp);1948 if (error)1949 goto out_free;1950 1951 /* Now iterate the list to free the leftovers */1952 list_for_each_entry_safe(rr, n, &debris, rr_list) {1953 /* Set up transaction. */1954 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);1955 if (error)1956 goto out_free;1957 1958 /* Free the orphan record */1959 fsb = XFS_AGB_TO_FSB(mp, pag->pag_agno,1960 rr->rr_rrec.rc_startblock);1961 xfs_refcount_free_cow_extent(tp, fsb,1962 rr->rr_rrec.rc_blockcount);1963 1964 /* Free the block. */1965 error = xfs_free_extent_later(tp, fsb,1966 rr->rr_rrec.rc_blockcount, NULL,1967 XFS_AG_RESV_NONE, 0);1968 if (error)1969 goto out_trans;1970 1971 error = xfs_trans_commit(tp);1972 if (error)1973 goto out_free;1974 1975 list_del(&rr->rr_list);1976 kfree(rr);1977 }1978 1979 return error;1980out_trans:1981 xfs_trans_cancel(tp);1982out_free:1983 /* Free the leftover list */1984 list_for_each_entry_safe(rr, n, &debris, rr_list) {1985 list_del(&rr->rr_list);1986 kfree(rr);1987 }1988 return error;1989}1990 1991/*1992 * Scan part of the keyspace of the refcount records and tell us if the area1993 * has no records, is fully mapped by records, or is partially filled.1994 */1995int1996xfs_refcount_has_records(1997 struct xfs_btree_cur *cur,1998 enum xfs_refc_domain domain,1999 xfs_agblock_t bno,2000 xfs_extlen_t len,2001 enum xbtree_recpacking *outcome)2002{2003 union xfs_btree_irec low;2004 union xfs_btree_irec high;2005 2006 memset(&low, 0, sizeof(low));2007 low.rc.rc_startblock = bno;2008 memset(&high, 0xFF, sizeof(high));2009 high.rc.rc_startblock = bno + len - 1;2010 low.rc.rc_domain = high.rc.rc_domain = domain;2011 2012 return xfs_btree_has_records(cur, &low, &high, NULL, outcome);2013}2014 2015struct xfs_refcount_query_range_info {2016 xfs_refcount_query_range_fn fn;2017 void *priv;2018};2019 2020/* Format btree record and pass to our callback. */2021STATIC int2022xfs_refcount_query_range_helper(2023 struct xfs_btree_cur *cur,2024 const union xfs_btree_rec *rec,2025 void *priv)2026{2027 struct xfs_refcount_query_range_info *query = priv;2028 struct xfs_refcount_irec irec;2029 xfs_failaddr_t fa;2030 2031 xfs_refcount_btrec_to_irec(rec, &irec);2032 fa = xfs_refcount_check_irec(cur->bc_ag.pag, &irec);2033 if (fa)2034 return xfs_refcount_complain_bad_rec(cur, fa, &irec);2035 2036 return query->fn(cur, &irec, query->priv);2037}2038 2039/* Find all refcount records between two keys. */2040int2041xfs_refcount_query_range(2042 struct xfs_btree_cur *cur,2043 const struct xfs_refcount_irec *low_rec,2044 const struct xfs_refcount_irec *high_rec,2045 xfs_refcount_query_range_fn fn,2046 void *priv)2047{2048 union xfs_btree_irec low_brec = { .rc = *low_rec };2049 union xfs_btree_irec high_brec = { .rc = *high_rec };2050 struct xfs_refcount_query_range_info query = { .priv = priv, .fn = fn };2051 2052 return xfs_btree_query_range(cur, &low_brec, &high_brec,2053 xfs_refcount_query_range_helper, &query);2054}2055 2056int __init2057xfs_refcount_intent_init_cache(void)2058{2059 xfs_refcount_intent_cache = kmem_cache_create("xfs_refc_intent",2060 sizeof(struct xfs_refcount_intent),2061 0, 0, NULL);2062 2063 return xfs_refcount_intent_cache != NULL ? 0 : -ENOMEM;2064}2065 2066void2067xfs_refcount_intent_destroy_cache(void)2068{2069 kmem_cache_destroy(xfs_refcount_intent_cache);2070 xfs_refcount_intent_cache = NULL;2071}2072