1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (C) 2018 Oracle. All Rights Reserved. 4 * Author: Darrick J. Wong <darrick.wong@oracle.com> 5 */ 6 #include "xfs.h" 7 #include "xfs_fs.h" 8 #include "xfs_shared.h" 9 #include "xfs_format.h" 10 #include "xfs_trans_resv.h" 11 #include "xfs_mount.h" 12 #include "xfs_btree.h" 13 #include "xfs_log_format.h" 14 #include "xfs_trans.h" 15 #include "xfs_sb.h" 16 #include "xfs_inode.h" 17 #include "xfs_alloc.h" 18 #include "xfs_alloc_btree.h" 19 #include "xfs_ialloc.h" 20 #include "xfs_ialloc_btree.h" 21 #include "xfs_rmap.h" 22 #include "xfs_rmap_btree.h" 23 #include "xfs_refcount_btree.h" 24 #include "xfs_extent_busy.h" 25 #include "xfs_ag_resv.h" 26 #include "xfs_quota.h" 27 #include "scrub/scrub.h" 28 #include "scrub/common.h" 29 #include "scrub/trace.h" 30 #include "scrub/repair.h" 31 #include "scrub/bitmap.h" 32 33 /* 34 * Attempt to repair some metadata, if the metadata is corrupt and userspace 35 * told us to fix it. This function returns -EAGAIN to mean "re-run scrub", 36 * and will set *fixed to true if it thinks it repaired anything. 37 */ 38 int 39 xrep_attempt( 40 struct xfs_inode *ip, 41 struct xfs_scrub *sc) 42 { 43 int error = 0; 44 45 trace_xrep_attempt(ip, sc->sm, error); 46 47 xchk_ag_btcur_free(&sc->sa); 48 49 /* Repair whatever's broken. */ 50 ASSERT(sc->ops->repair); 51 error = sc->ops->repair(sc); 52 trace_xrep_done(ip, sc->sm, error); 53 switch (error) { 54 case 0: 55 /* 56 * Repair succeeded. Commit the fixes and perform a second 57 * scrub so that we can tell userspace if we fixed the problem. 58 */ 59 sc->sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT; 60 sc->flags |= XREP_ALREADY_FIXED; 61 return -EAGAIN; 62 case -EDEADLOCK: 63 case -EAGAIN: 64 /* Tell the caller to try again having grabbed all the locks. */ 65 if (!(sc->flags & XCHK_TRY_HARDER)) { 66 sc->flags |= XCHK_TRY_HARDER; 67 return -EAGAIN; 68 } 69 /* 70 * We tried harder but still couldn't grab all the resources 71 * we needed to fix it. The corruption has not been fixed, 72 * so report back to userspace. 73 */ 74 return -EFSCORRUPTED; 75 default: 76 return error; 77 } 78 } 79 80 /* 81 * Complain about unfixable problems in the filesystem. We don't log 82 * corruptions when IFLAG_REPAIR wasn't set on the assumption that the driver 83 * program is xfs_scrub, which will call back with IFLAG_REPAIR set if the 84 * administrator isn't running xfs_scrub in no-repairs mode. 85 * 86 * Use this helper function because _ratelimited silently declares a static 87 * structure to track rate limiting information. 88 */ 89 void 90 xrep_failure( 91 struct xfs_mount *mp) 92 { 93 xfs_alert_ratelimited(mp, 94 "Corruption not fixed during online repair. Unmount and run xfs_repair."); 95 } 96 97 /* 98 * Repair probe -- userspace uses this to probe if we're willing to repair a 99 * given mountpoint. 100 */ 101 int 102 xrep_probe( 103 struct xfs_scrub *sc) 104 { 105 int error = 0; 106 107 if (xchk_should_terminate(sc, &error)) 108 return error; 109 110 return 0; 111 } 112 113 /* 114 * Roll a transaction, keeping the AG headers locked and reinitializing 115 * the btree cursors. 116 */ 117 int 118 xrep_roll_ag_trans( 119 struct xfs_scrub *sc) 120 { 121 int error; 122 123 /* Keep the AG header buffers locked so we can keep going. */ 124 if (sc->sa.agi_bp) 125 xfs_trans_bhold(sc->tp, sc->sa.agi_bp); 126 if (sc->sa.agf_bp) 127 xfs_trans_bhold(sc->tp, sc->sa.agf_bp); 128 if (sc->sa.agfl_bp) 129 xfs_trans_bhold(sc->tp, sc->sa.agfl_bp); 130 131 /* 132 * Roll the transaction. We still own the buffer and the buffer lock 133 * regardless of whether or not the roll succeeds. If the roll fails, 134 * the buffers will be released during teardown on our way out of the 135 * kernel. If it succeeds, we join them to the new transaction and 136 * move on. 137 */ 138 error = xfs_trans_roll(&sc->tp); 139 if (error) 140 return error; 141 142 /* Join AG headers to the new transaction. */ 143 if (sc->sa.agi_bp) 144 xfs_trans_bjoin(sc->tp, sc->sa.agi_bp); 145 if (sc->sa.agf_bp) 146 xfs_trans_bjoin(sc->tp, sc->sa.agf_bp); 147 if (sc->sa.agfl_bp) 148 xfs_trans_bjoin(sc->tp, sc->sa.agfl_bp); 149 150 return 0; 151 } 152 153 /* 154 * Does the given AG have enough space to rebuild a btree? Neither AG 155 * reservation can be critical, and we must have enough space (factoring 156 * in AG reservations) to construct a whole btree. 157 */ 158 bool 159 xrep_ag_has_space( 160 struct xfs_perag *pag, 161 xfs_extlen_t nr_blocks, 162 enum xfs_ag_resv_type type) 163 { 164 return !xfs_ag_resv_critical(pag, XFS_AG_RESV_RMAPBT) && 165 !xfs_ag_resv_critical(pag, XFS_AG_RESV_METADATA) && 166 pag->pagf_freeblks > xfs_ag_resv_needed(pag, type) + nr_blocks; 167 } 168 169 /* 170 * Figure out how many blocks to reserve for an AG repair. We calculate the 171 * worst case estimate for the number of blocks we'd need to rebuild one of 172 * any type of per-AG btree. 173 */ 174 xfs_extlen_t 175 xrep_calc_ag_resblks( 176 struct xfs_scrub *sc) 177 { 178 struct xfs_mount *mp = sc->mp; 179 struct xfs_scrub_metadata *sm = sc->sm; 180 struct xfs_perag *pag; 181 struct xfs_buf *bp; 182 xfs_agino_t icount = NULLAGINO; 183 xfs_extlen_t aglen = NULLAGBLOCK; 184 xfs_extlen_t usedlen; 185 xfs_extlen_t freelen; 186 xfs_extlen_t bnobt_sz; 187 xfs_extlen_t inobt_sz; 188 xfs_extlen_t rmapbt_sz; 189 xfs_extlen_t refcbt_sz; 190 int error; 191 192 if (!(sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)) 193 return 0; 194 195 pag = xfs_perag_get(mp, sm->sm_agno); 196 if (pag->pagi_init) { 197 /* Use in-core icount if possible. */ 198 icount = pag->pagi_count; 199 } else { 200 /* Try to get the actual counters from disk. */ 201 error = xfs_ialloc_read_agi(mp, NULL, sm->sm_agno, &bp); 202 if (!error) { 203 icount = pag->pagi_count; 204 xfs_buf_relse(bp); 205 } 206 } 207 208 /* Now grab the block counters from the AGF. */ 209 error = xfs_alloc_read_agf(mp, NULL, sm->sm_agno, 0, &bp); 210 if (!error) { 211 aglen = be32_to_cpu(XFS_BUF_TO_AGF(bp)->agf_length); 212 freelen = be32_to_cpu(XFS_BUF_TO_AGF(bp)->agf_freeblks); 213 usedlen = aglen - freelen; 214 xfs_buf_relse(bp); 215 } 216 xfs_perag_put(pag); 217 218 /* If the icount is impossible, make some worst-case assumptions. */ 219 if (icount == NULLAGINO || 220 !xfs_verify_agino(mp, sm->sm_agno, icount)) { 221 xfs_agino_t first, last; 222 223 xfs_agino_range(mp, sm->sm_agno, &first, &last); 224 icount = last - first + 1; 225 } 226 227 /* If the block counts are impossible, make worst-case assumptions. */ 228 if (aglen == NULLAGBLOCK || 229 aglen != xfs_ag_block_count(mp, sm->sm_agno) || 230 freelen >= aglen) { 231 aglen = xfs_ag_block_count(mp, sm->sm_agno); 232 freelen = aglen; 233 usedlen = aglen; 234 } 235 236 trace_xrep_calc_ag_resblks(mp, sm->sm_agno, icount, aglen, 237 freelen, usedlen); 238 239 /* 240 * Figure out how many blocks we'd need worst case to rebuild 241 * each type of btree. Note that we can only rebuild the 242 * bnobt/cntbt or inobt/finobt as pairs. 243 */ 244 bnobt_sz = 2 * xfs_allocbt_calc_size(mp, freelen); 245 if (xfs_sb_version_hassparseinodes(&mp->m_sb)) 246 inobt_sz = xfs_iallocbt_calc_size(mp, icount / 247 XFS_INODES_PER_HOLEMASK_BIT); 248 else 249 inobt_sz = xfs_iallocbt_calc_size(mp, icount / 250 XFS_INODES_PER_CHUNK); 251 if (xfs_sb_version_hasfinobt(&mp->m_sb)) 252 inobt_sz *= 2; 253 if (xfs_sb_version_hasreflink(&mp->m_sb)) 254 refcbt_sz = xfs_refcountbt_calc_size(mp, usedlen); 255 else 256 refcbt_sz = 0; 257 if (xfs_sb_version_hasrmapbt(&mp->m_sb)) { 258 /* 259 * Guess how many blocks we need to rebuild the rmapbt. 260 * For non-reflink filesystems we can't have more records than 261 * used blocks. However, with reflink it's possible to have 262 * more than one rmap record per AG block. We don't know how 263 * many rmaps there could be in the AG, so we start off with 264 * what we hope is an generous over-estimation. 265 */ 266 if (xfs_sb_version_hasreflink(&mp->m_sb)) 267 rmapbt_sz = xfs_rmapbt_calc_size(mp, 268 (unsigned long long)aglen * 2); 269 else 270 rmapbt_sz = xfs_rmapbt_calc_size(mp, usedlen); 271 } else { 272 rmapbt_sz = 0; 273 } 274 275 trace_xrep_calc_ag_resblks_btsize(mp, sm->sm_agno, bnobt_sz, 276 inobt_sz, rmapbt_sz, refcbt_sz); 277 278 return max(max(bnobt_sz, inobt_sz), max(rmapbt_sz, refcbt_sz)); 279 } 280 281 /* Allocate a block in an AG. */ 282 int 283 xrep_alloc_ag_block( 284 struct xfs_scrub *sc, 285 const struct xfs_owner_info *oinfo, 286 xfs_fsblock_t *fsbno, 287 enum xfs_ag_resv_type resv) 288 { 289 struct xfs_alloc_arg args = {0}; 290 xfs_agblock_t bno; 291 int error; 292 293 switch (resv) { 294 case XFS_AG_RESV_AGFL: 295 case XFS_AG_RESV_RMAPBT: 296 error = xfs_alloc_get_freelist(sc->tp, sc->sa.agf_bp, &bno, 1); 297 if (error) 298 return error; 299 if (bno == NULLAGBLOCK) 300 return -ENOSPC; 301 xfs_extent_busy_reuse(sc->mp, sc->sa.agno, bno, 302 1, false); 303 *fsbno = XFS_AGB_TO_FSB(sc->mp, sc->sa.agno, bno); 304 if (resv == XFS_AG_RESV_RMAPBT) 305 xfs_ag_resv_rmapbt_alloc(sc->mp, sc->sa.agno); 306 return 0; 307 default: 308 break; 309 } 310 311 args.tp = sc->tp; 312 args.mp = sc->mp; 313 args.oinfo = *oinfo; 314 args.fsbno = XFS_AGB_TO_FSB(args.mp, sc->sa.agno, 0); 315 args.minlen = 1; 316 args.maxlen = 1; 317 args.prod = 1; 318 args.type = XFS_ALLOCTYPE_THIS_AG; 319 args.resv = resv; 320 321 error = xfs_alloc_vextent(&args); 322 if (error) 323 return error; 324 if (args.fsbno == NULLFSBLOCK) 325 return -ENOSPC; 326 ASSERT(args.len == 1); 327 *fsbno = args.fsbno; 328 329 return 0; 330 } 331 332 /* Initialize a new AG btree root block with zero entries. */ 333 int 334 xrep_init_btblock( 335 struct xfs_scrub *sc, 336 xfs_fsblock_t fsb, 337 struct xfs_buf **bpp, 338 xfs_btnum_t btnum, 339 const struct xfs_buf_ops *ops) 340 { 341 struct xfs_trans *tp = sc->tp; 342 struct xfs_mount *mp = sc->mp; 343 struct xfs_buf *bp; 344 345 trace_xrep_init_btblock(mp, XFS_FSB_TO_AGNO(mp, fsb), 346 XFS_FSB_TO_AGBNO(mp, fsb), btnum); 347 348 ASSERT(XFS_FSB_TO_AGNO(mp, fsb) == sc->sa.agno); 349 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, XFS_FSB_TO_DADDR(mp, fsb), 350 XFS_FSB_TO_BB(mp, 1), 0); 351 xfs_buf_zero(bp, 0, BBTOB(bp->b_length)); 352 xfs_btree_init_block(mp, bp, btnum, 0, 0, sc->sa.agno); 353 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_BTREE_BUF); 354 xfs_trans_log_buf(tp, bp, 0, BBTOB(bp->b_length) - 1); 355 bp->b_ops = ops; 356 *bpp = bp; 357 358 return 0; 359 } 360 361 /* 362 * Reconstructing per-AG Btrees 363 * 364 * When a space btree is corrupt, we don't bother trying to fix it. Instead, 365 * we scan secondary space metadata to derive the records that should be in 366 * the damaged btree, initialize a fresh btree root, and insert the records. 367 * Note that for rebuilding the rmapbt we scan all the primary data to 368 * generate the new records. 369 * 370 * However, that leaves the matter of removing all the metadata describing the 371 * old broken structure. For primary metadata we use the rmap data to collect 372 * every extent with a matching rmap owner (bitmap); we then iterate all other 373 * metadata structures with the same rmap owner to collect the extents that 374 * cannot be removed (sublist). We then subtract sublist from bitmap to 375 * derive the blocks that were used by the old btree. These blocks can be 376 * reaped. 377 * 378 * For rmapbt reconstructions we must use different tactics for extent 379 * collection. First we iterate all primary metadata (this excludes the old 380 * rmapbt, obviously) to generate new rmap records. The gaps in the rmap 381 * records are collected as bitmap. The bnobt records are collected as 382 * sublist. As with the other btrees we subtract sublist from bitmap, and the 383 * result (since the rmapbt lives in the free space) are the blocks from the 384 * old rmapbt. 385 * 386 * Disposal of Blocks from Old per-AG Btrees 387 * 388 * Now that we've constructed a new btree to replace the damaged one, we want 389 * to dispose of the blocks that (we think) the old btree was using. 390 * Previously, we used the rmapbt to collect the extents (bitmap) with the 391 * rmap owner corresponding to the tree we rebuilt, collected extents for any 392 * blocks with the same rmap owner that are owned by another data structure 393 * (sublist), and subtracted sublist from bitmap. In theory the extents 394 * remaining in bitmap are the old btree's blocks. 395 * 396 * Unfortunately, it's possible that the btree was crosslinked with other 397 * blocks on disk. The rmap data can tell us if there are multiple owners, so 398 * if the rmapbt says there is an owner of this block other than @oinfo, then 399 * the block is crosslinked. Remove the reverse mapping and continue. 400 * 401 * If there is one rmap record, we can free the block, which removes the 402 * reverse mapping but doesn't add the block to the free space. Our repair 403 * strategy is to hope the other metadata objects crosslinked on this block 404 * will be rebuilt (atop different blocks), thereby removing all the cross 405 * links. 406 * 407 * If there are no rmap records at all, we also free the block. If the btree 408 * being rebuilt lives in the free space (bnobt/cntbt/rmapbt) then there isn't 409 * supposed to be a rmap record and everything is ok. For other btrees there 410 * had to have been an rmap entry for the block to have ended up on @bitmap, 411 * so if it's gone now there's something wrong and the fs will shut down. 412 * 413 * Note: If there are multiple rmap records with only the same rmap owner as 414 * the btree we're trying to rebuild and the block is indeed owned by another 415 * data structure with the same rmap owner, then the block will be in sublist 416 * and therefore doesn't need disposal. If there are multiple rmap records 417 * with only the same rmap owner but the block is not owned by something with 418 * the same rmap owner, the block will be freed. 419 * 420 * The caller is responsible for locking the AG headers for the entire rebuild 421 * operation so that nothing else can sneak in and change the AG state while 422 * we're not looking. We also assume that the caller already invalidated any 423 * buffers associated with @bitmap. 424 */ 425 426 /* 427 * Invalidate buffers for per-AG btree blocks we're dumping. This function 428 * is not intended for use with file data repairs; we have bunmapi for that. 429 */ 430 int 431 xrep_invalidate_blocks( 432 struct xfs_scrub *sc, 433 struct xfs_bitmap *bitmap) 434 { 435 struct xfs_bitmap_range *bmr; 436 struct xfs_bitmap_range *n; 437 struct xfs_buf *bp; 438 xfs_fsblock_t fsbno; 439 440 /* 441 * For each block in each extent, see if there's an incore buffer for 442 * exactly that block; if so, invalidate it. The buffer cache only 443 * lets us look for one buffer at a time, so we have to look one block 444 * at a time. Avoid invalidating AG headers and post-EOFS blocks 445 * because we never own those; and if we can't TRYLOCK the buffer we 446 * assume it's owned by someone else. 447 */ 448 for_each_xfs_bitmap_block(fsbno, bmr, n, bitmap) { 449 /* Skip AG headers and post-EOFS blocks */ 450 if (!xfs_verify_fsbno(sc->mp, fsbno)) 451 continue; 452 bp = xfs_buf_incore(sc->mp->m_ddev_targp, 453 XFS_FSB_TO_DADDR(sc->mp, fsbno), 454 XFS_FSB_TO_BB(sc->mp, 1), XBF_TRYLOCK); 455 if (bp) { 456 xfs_trans_bjoin(sc->tp, bp); 457 xfs_trans_binval(sc->tp, bp); 458 } 459 } 460 461 return 0; 462 } 463 464 /* Ensure the freelist is the correct size. */ 465 int 466 xrep_fix_freelist( 467 struct xfs_scrub *sc, 468 bool can_shrink) 469 { 470 struct xfs_alloc_arg args = {0}; 471 472 args.mp = sc->mp; 473 args.tp = sc->tp; 474 args.agno = sc->sa.agno; 475 args.alignment = 1; 476 args.pag = sc->sa.pag; 477 478 return xfs_alloc_fix_freelist(&args, 479 can_shrink ? 0 : XFS_ALLOC_FLAG_NOSHRINK); 480 } 481 482 /* 483 * Put a block back on the AGFL. 484 */ 485 STATIC int 486 xrep_put_freelist( 487 struct xfs_scrub *sc, 488 xfs_agblock_t agbno) 489 { 490 int error; 491 492 /* Make sure there's space on the freelist. */ 493 error = xrep_fix_freelist(sc, true); 494 if (error) 495 return error; 496 497 /* 498 * Since we're "freeing" a lost block onto the AGFL, we have to 499 * create an rmap for the block prior to merging it or else other 500 * parts will break. 501 */ 502 error = xfs_rmap_alloc(sc->tp, sc->sa.agf_bp, sc->sa.agno, agbno, 1, 503 &XFS_RMAP_OINFO_AG); 504 if (error) 505 return error; 506 507 /* Put the block on the AGFL. */ 508 error = xfs_alloc_put_freelist(sc->tp, sc->sa.agf_bp, sc->sa.agfl_bp, 509 agbno, 0); 510 if (error) 511 return error; 512 xfs_extent_busy_insert(sc->tp, sc->sa.agno, agbno, 1, 513 XFS_EXTENT_BUSY_SKIP_DISCARD); 514 515 return 0; 516 } 517 518 /* Dispose of a single block. */ 519 STATIC int 520 xrep_reap_block( 521 struct xfs_scrub *sc, 522 xfs_fsblock_t fsbno, 523 const struct xfs_owner_info *oinfo, 524 enum xfs_ag_resv_type resv) 525 { 526 struct xfs_btree_cur *cur; 527 struct xfs_buf *agf_bp = NULL; 528 xfs_agnumber_t agno; 529 xfs_agblock_t agbno; 530 bool has_other_rmap; 531 int error; 532 533 agno = XFS_FSB_TO_AGNO(sc->mp, fsbno); 534 agbno = XFS_FSB_TO_AGBNO(sc->mp, fsbno); 535 536 /* 537 * If we are repairing per-inode metadata, we need to read in the AGF 538 * buffer. Otherwise, we're repairing a per-AG structure, so reuse 539 * the AGF buffer that the setup functions already grabbed. 540 */ 541 if (sc->ip) { 542 error = xfs_alloc_read_agf(sc->mp, sc->tp, agno, 0, &agf_bp); 543 if (error) 544 return error; 545 if (!agf_bp) 546 return -ENOMEM; 547 } else { 548 agf_bp = sc->sa.agf_bp; 549 } 550 cur = xfs_rmapbt_init_cursor(sc->mp, sc->tp, agf_bp, agno); 551 552 /* Can we find any other rmappings? */ 553 error = xfs_rmap_has_other_keys(cur, agbno, 1, oinfo, &has_other_rmap); 554 xfs_btree_del_cursor(cur, error); 555 if (error) 556 goto out_free; 557 558 /* 559 * If there are other rmappings, this block is cross linked and must 560 * not be freed. Remove the reverse mapping and move on. Otherwise, 561 * we were the only owner of the block, so free the extent, which will 562 * also remove the rmap. 563 * 564 * XXX: XFS doesn't support detecting the case where a single block 565 * metadata structure is crosslinked with a multi-block structure 566 * because the buffer cache doesn't detect aliasing problems, so we 567 * can't fix 100% of crosslinking problems (yet). The verifiers will 568 * blow on writeout, the filesystem will shut down, and the admin gets 569 * to run xfs_repair. 570 */ 571 if (has_other_rmap) 572 error = xfs_rmap_free(sc->tp, agf_bp, agno, agbno, 1, oinfo); 573 else if (resv == XFS_AG_RESV_AGFL) 574 error = xrep_put_freelist(sc, agbno); 575 else 576 error = xfs_free_extent(sc->tp, fsbno, 1, oinfo, resv); 577 if (agf_bp != sc->sa.agf_bp) 578 xfs_trans_brelse(sc->tp, agf_bp); 579 if (error) 580 return error; 581 582 if (sc->ip) 583 return xfs_trans_roll_inode(&sc->tp, sc->ip); 584 return xrep_roll_ag_trans(sc); 585 586 out_free: 587 if (agf_bp != sc->sa.agf_bp) 588 xfs_trans_brelse(sc->tp, agf_bp); 589 return error; 590 } 591 592 /* Dispose of every block of every extent in the bitmap. */ 593 int 594 xrep_reap_extents( 595 struct xfs_scrub *sc, 596 struct xfs_bitmap *bitmap, 597 const struct xfs_owner_info *oinfo, 598 enum xfs_ag_resv_type type) 599 { 600 struct xfs_bitmap_range *bmr; 601 struct xfs_bitmap_range *n; 602 xfs_fsblock_t fsbno; 603 int error = 0; 604 605 ASSERT(xfs_sb_version_hasrmapbt(&sc->mp->m_sb)); 606 607 for_each_xfs_bitmap_block(fsbno, bmr, n, bitmap) { 608 ASSERT(sc->ip != NULL || 609 XFS_FSB_TO_AGNO(sc->mp, fsbno) == sc->sa.agno); 610 trace_xrep_dispose_btree_extent(sc->mp, 611 XFS_FSB_TO_AGNO(sc->mp, fsbno), 612 XFS_FSB_TO_AGBNO(sc->mp, fsbno), 1); 613 614 error = xrep_reap_block(sc, fsbno, oinfo, type); 615 if (error) 616 goto out; 617 } 618 619 out: 620 xfs_bitmap_destroy(bitmap); 621 return error; 622 } 623 624 /* 625 * Finding per-AG Btree Roots for AGF/AGI Reconstruction 626 * 627 * If the AGF or AGI become slightly corrupted, it may be necessary to rebuild 628 * the AG headers by using the rmap data to rummage through the AG looking for 629 * btree roots. This is not guaranteed to work if the AG is heavily damaged 630 * or the rmap data are corrupt. 631 * 632 * Callers of xrep_find_ag_btree_roots must lock the AGF and AGFL 633 * buffers if the AGF is being rebuilt; or the AGF and AGI buffers if the 634 * AGI is being rebuilt. It must maintain these locks until it's safe for 635 * other threads to change the btrees' shapes. The caller provides 636 * information about the btrees to look for by passing in an array of 637 * xrep_find_ag_btree with the (rmap owner, buf_ops, magic) fields set. 638 * The (root, height) fields will be set on return if anything is found. The 639 * last element of the array should have a NULL buf_ops to mark the end of the 640 * array. 641 * 642 * For every rmapbt record matching any of the rmap owners in btree_info, 643 * read each block referenced by the rmap record. If the block is a btree 644 * block from this filesystem matching any of the magic numbers and has a 645 * level higher than what we've already seen, remember the block and the 646 * height of the tree required to have such a block. When the call completes, 647 * we return the highest block we've found for each btree description; those 648 * should be the roots. 649 */ 650 651 struct xrep_findroot { 652 struct xfs_scrub *sc; 653 struct xfs_buf *agfl_bp; 654 struct xfs_agf *agf; 655 struct xrep_find_ag_btree *btree_info; 656 }; 657 658 /* See if our block is in the AGFL. */ 659 STATIC int 660 xrep_findroot_agfl_walk( 661 struct xfs_mount *mp, 662 xfs_agblock_t bno, 663 void *priv) 664 { 665 xfs_agblock_t *agbno = priv; 666 667 return (*agbno == bno) ? -ECANCELED : 0; 668 } 669 670 /* Does this block match the btree information passed in? */ 671 STATIC int 672 xrep_findroot_block( 673 struct xrep_findroot *ri, 674 struct xrep_find_ag_btree *fab, 675 uint64_t owner, 676 xfs_agblock_t agbno, 677 bool *done_with_block) 678 { 679 struct xfs_mount *mp = ri->sc->mp; 680 struct xfs_buf *bp; 681 struct xfs_btree_block *btblock; 682 xfs_daddr_t daddr; 683 int block_level; 684 int error = 0; 685 686 daddr = XFS_AGB_TO_DADDR(mp, ri->sc->sa.agno, agbno); 687 688 /* 689 * Blocks in the AGFL have stale contents that might just happen to 690 * have a matching magic and uuid. We don't want to pull these blocks 691 * in as part of a tree root, so we have to filter out the AGFL stuff 692 * here. If the AGFL looks insane we'll just refuse to repair. 693 */ 694 if (owner == XFS_RMAP_OWN_AG) { 695 error = xfs_agfl_walk(mp, ri->agf, ri->agfl_bp, 696 xrep_findroot_agfl_walk, &agbno); 697 if (error == -ECANCELED) 698 return 0; 699 if (error) 700 return error; 701 } 702 703 /* 704 * Read the buffer into memory so that we can see if it's a match for 705 * our btree type. We have no clue if it is beforehand, and we want to 706 * avoid xfs_trans_read_buf's behavior of dumping the DONE state (which 707 * will cause needless disk reads in subsequent calls to this function) 708 * and logging metadata verifier failures. 709 * 710 * Therefore, pass in NULL buffer ops. If the buffer was already in 711 * memory from some other caller it will already have b_ops assigned. 712 * If it was in memory from a previous unsuccessful findroot_block 713 * call, the buffer won't have b_ops but it should be clean and ready 714 * for us to try to verify if the read call succeeds. The same applies 715 * if the buffer wasn't in memory at all. 716 * 717 * Note: If we never match a btree type with this buffer, it will be 718 * left in memory with NULL b_ops. This shouldn't be a problem unless 719 * the buffer gets written. 720 */ 721 error = xfs_trans_read_buf(mp, ri->sc->tp, mp->m_ddev_targp, daddr, 722 mp->m_bsize, 0, &bp, NULL); 723 if (error) 724 return error; 725 726 /* Ensure the block magic matches the btree type we're looking for. */ 727 btblock = XFS_BUF_TO_BLOCK(bp); 728 ASSERT(fab->buf_ops->magic[1] != 0); 729 if (btblock->bb_magic != fab->buf_ops->magic[1]) 730 goto out; 731 732 /* 733 * If the buffer already has ops applied and they're not the ones for 734 * this btree type, we know this block doesn't match the btree and we 735 * can bail out. 736 * 737 * If the buffer ops match ours, someone else has already validated 738 * the block for us, so we can move on to checking if this is a root 739 * block candidate. 740 * 741 * If the buffer does not have ops, nobody has successfully validated 742 * the contents and the buffer cannot be dirty. If the magic, uuid, 743 * and structure match this btree type then we'll move on to checking 744 * if it's a root block candidate. If there is no match, bail out. 745 */ 746 if (bp->b_ops) { 747 if (bp->b_ops != fab->buf_ops) 748 goto out; 749 } else { 750 ASSERT(!xfs_trans_buf_is_dirty(bp)); 751 if (!uuid_equal(&btblock->bb_u.s.bb_uuid, 752 &mp->m_sb.sb_meta_uuid)) 753 goto out; 754 /* 755 * Read verifiers can reference b_ops, so we set the pointer 756 * here. If the verifier fails we'll reset the buffer state 757 * to what it was before we touched the buffer. 758 */ 759 bp->b_ops = fab->buf_ops; 760 fab->buf_ops->verify_read(bp); 761 if (bp->b_error) { 762 bp->b_ops = NULL; 763 bp->b_error = 0; 764 goto out; 765 } 766 767 /* 768 * Some read verifiers will (re)set b_ops, so we must be 769 * careful not to change b_ops after running the verifier. 770 */ 771 } 772 773 /* 774 * This block passes the magic/uuid and verifier tests for this btree 775 * type. We don't need the caller to try the other tree types. 776 */ 777 *done_with_block = true; 778 779 /* 780 * Compare this btree block's level to the height of the current 781 * candidate root block. 782 * 783 * If the level matches the root we found previously, throw away both 784 * blocks because there can't be two candidate roots. 785 * 786 * If level is lower in the tree than the root we found previously, 787 * ignore this block. 788 */ 789 block_level = xfs_btree_get_level(btblock); 790 if (block_level + 1 == fab->height) { 791 fab->root = NULLAGBLOCK; 792 goto out; 793 } else if (block_level < fab->height) { 794 goto out; 795 } 796 797 /* 798 * This is the highest block in the tree that we've found so far. 799 * Update the btree height to reflect what we've learned from this 800 * block. 801 */ 802 fab->height = block_level + 1; 803 804 /* 805 * If this block doesn't have sibling pointers, then it's the new root 806 * block candidate. Otherwise, the root will be found farther up the 807 * tree. 808 */ 809 if (btblock->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK) && 810 btblock->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK)) 811 fab->root = agbno; 812 else 813 fab->root = NULLAGBLOCK; 814 815 trace_xrep_findroot_block(mp, ri->sc->sa.agno, agbno, 816 be32_to_cpu(btblock->bb_magic), fab->height - 1); 817 out: 818 xfs_trans_brelse(ri->sc->tp, bp); 819 return error; 820 } 821 822 /* 823 * Do any of the blocks in this rmap record match one of the btrees we're 824 * looking for? 825 */ 826 STATIC int 827 xrep_findroot_rmap( 828 struct xfs_btree_cur *cur, 829 struct xfs_rmap_irec *rec, 830 void *priv) 831 { 832 struct xrep_findroot *ri = priv; 833 struct xrep_find_ag_btree *fab; 834 xfs_agblock_t b; 835 bool done; 836 int error = 0; 837 838 /* Ignore anything that isn't AG metadata. */ 839 if (!XFS_RMAP_NON_INODE_OWNER(rec->rm_owner)) 840 return 0; 841 842 /* Otherwise scan each block + btree type. */ 843 for (b = 0; b < rec->rm_blockcount; b++) { 844 done = false; 845 for (fab = ri->btree_info; fab->buf_ops; fab++) { 846 if (rec->rm_owner != fab->rmap_owner) 847 continue; 848 error = xrep_findroot_block(ri, fab, 849 rec->rm_owner, rec->rm_startblock + b, 850 &done); 851 if (error) 852 return error; 853 if (done) 854 break; 855 } 856 } 857 858 return 0; 859 } 860 861 /* Find the roots of the per-AG btrees described in btree_info. */ 862 int 863 xrep_find_ag_btree_roots( 864 struct xfs_scrub *sc, 865 struct xfs_buf *agf_bp, 866 struct xrep_find_ag_btree *btree_info, 867 struct xfs_buf *agfl_bp) 868 { 869 struct xfs_mount *mp = sc->mp; 870 struct xrep_findroot ri; 871 struct xrep_find_ag_btree *fab; 872 struct xfs_btree_cur *cur; 873 int error; 874 875 ASSERT(xfs_buf_islocked(agf_bp)); 876 ASSERT(agfl_bp == NULL || xfs_buf_islocked(agfl_bp)); 877 878 ri.sc = sc; 879 ri.btree_info = btree_info; 880 ri.agf = XFS_BUF_TO_AGF(agf_bp); 881 ri.agfl_bp = agfl_bp; 882 for (fab = btree_info; fab->buf_ops; fab++) { 883 ASSERT(agfl_bp || fab->rmap_owner != XFS_RMAP_OWN_AG); 884 ASSERT(XFS_RMAP_NON_INODE_OWNER(fab->rmap_owner)); 885 fab->root = NULLAGBLOCK; 886 fab->height = 0; 887 } 888 889 cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno); 890 error = xfs_rmap_query_all(cur, xrep_findroot_rmap, &ri); 891 xfs_btree_del_cursor(cur, error); 892 893 return error; 894 } 895 896 /* Force a quotacheck the next time we mount. */ 897 void 898 xrep_force_quotacheck( 899 struct xfs_scrub *sc, 900 uint dqtype) 901 { 902 uint flag; 903 904 flag = xfs_quota_chkd_flag(dqtype); 905 if (!(flag & sc->mp->m_qflags)) 906 return; 907 908 sc->mp->m_qflags &= ~flag; 909 spin_lock(&sc->mp->m_sb_lock); 910 sc->mp->m_sb.sb_qflags &= ~flag; 911 spin_unlock(&sc->mp->m_sb_lock); 912 xfs_log_sb(sc->tp); 913 } 914 915 /* 916 * Attach dquots to this inode, or schedule quotacheck to fix them. 917 * 918 * This function ensures that the appropriate dquots are attached to an inode. 919 * We cannot allow the dquot code to allocate an on-disk dquot block here 920 * because we're already in transaction context with the inode locked. The 921 * on-disk dquot should already exist anyway. If the quota code signals 922 * corruption or missing quota information, schedule quotacheck, which will 923 * repair corruptions in the quota metadata. 924 */ 925 int 926 xrep_ino_dqattach( 927 struct xfs_scrub *sc) 928 { 929 int error; 930 931 error = xfs_qm_dqattach_locked(sc->ip, false); 932 switch (error) { 933 case -EFSBADCRC: 934 case -EFSCORRUPTED: 935 case -ENOENT: 936 xfs_err_ratelimited(sc->mp, 937 "inode %llu repair encountered quota error %d, quotacheck forced.", 938 (unsigned long long)sc->ip->i_ino, error); 939 if (XFS_IS_UQUOTA_ON(sc->mp) && !sc->ip->i_udquot) 940 xrep_force_quotacheck(sc, XFS_DQ_USER); 941 if (XFS_IS_GQUOTA_ON(sc->mp) && !sc->ip->i_gdquot) 942 xrep_force_quotacheck(sc, XFS_DQ_GROUP); 943 if (XFS_IS_PQUOTA_ON(sc->mp) && !sc->ip->i_pdquot) 944 xrep_force_quotacheck(sc, XFS_DQ_PROJ); 945 /* fall through */ 946 case -ESRCH: 947 error = 0; 948 break; 949 default: 950 break; 951 } 952 953 return error; 954 } 955