root/fs/xfs/scrub/bmap.c

DEFINITIONS

1. xchk_setup_inode_bmap
2. xchk_bmap_get_rmap
3. xchk_bmap_xref_rmap
4. xchk_bmap_rt_iextent_xref
5. xchk_bmap_iextent_xref
6. xchk_bmap_dirattr_extent
7. xchk_bmap_iextent
8. xchk_bmapbt_rec
9. xchk_bmap_btree
10. xchk_bmap_check_rmap
11. xchk_bmap_check_ag_rmaps
12. xchk_bmap_check_rmaps
13. xchk_bmap
14. xchk_bmap_data
15. xchk_bmap_attr
16. xchk_bmap_cow

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2017 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_bit.h"
  14 #include "xfs_log_format.h"
  15 #include "xfs_trans.h"
  16 #include "xfs_inode.h"
  17 #include "xfs_alloc.h"
  18 #include "xfs_bmap.h"
  19 #include "xfs_bmap_btree.h"
  20 #include "xfs_rmap.h"
  21 #include "xfs_rmap_btree.h"
  22 #include "scrub/scrub.h"
  23 #include "scrub/common.h"
  24 #include "scrub/btree.h"
  25 
  26 /* Set us up with an inode's bmap. */
  27 int
  28 xchk_setup_inode_bmap(
  29         struct xfs_scrub        *sc,
  30         struct xfs_inode        *ip)
  31 {
  32         int                     error;
  33 
  34         error = xchk_get_inode(sc, ip);
  35         if (error)
  36                 goto out;
  37 
  38         sc->ilock_flags = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
  39         xfs_ilock(sc->ip, sc->ilock_flags);
  40 
  41         /*
  42          * We don't want any ephemeral data fork updates sitting around
  43          * while we inspect block mappings, so wait for directio to finish
  44          * and flush dirty data if we have delalloc reservations.
  45          */
  46         if (S_ISREG(VFS_I(sc->ip)->i_mode) &&
  47             sc->sm->sm_type == XFS_SCRUB_TYPE_BMBTD) {
  48                 inode_dio_wait(VFS_I(sc->ip));
  49                 error = filemap_write_and_wait(VFS_I(sc->ip)->i_mapping);
  50                 if (error)
  51                         goto out;
  52         }
  53 
  54         /* Got the inode, lock it and we're ready to go. */
  55         error = xchk_trans_alloc(sc, 0);
  56         if (error)
  57                 goto out;
  58         sc->ilock_flags |= XFS_ILOCK_EXCL;
  59         xfs_ilock(sc->ip, XFS_ILOCK_EXCL);
  60 
  61 out:
  62         /* scrub teardown will unlock and release the inode */
  63         return error;
  64 }
  65 
  66 /*
  67  * Inode fork block mapping (BMBT) scrubber.
  68  * More complex than the others because we have to scrub
  69  * all the extents regardless of whether or not the fork
  70  * is in btree format.
  71  */
  72 
  73 struct xchk_bmap_info {
  74         struct xfs_scrub        *sc;
  75         xfs_fileoff_t           lastoff;
  76         bool                    is_rt;
  77         bool                    is_shared;
  78         bool                    was_loaded;
  79         int                     whichfork;
  80 };
  81 
  82 /* Look for a corresponding rmap for this irec. */
  83 static inline bool
  84 xchk_bmap_get_rmap(
  85         struct xchk_bmap_info   *info,
  86         struct xfs_bmbt_irec    *irec,
  87         xfs_agblock_t           agbno,
  88         uint64_t                owner,
  89         struct xfs_rmap_irec    *rmap)
  90 {
  91         xfs_fileoff_t           offset;
  92         unsigned int            rflags = 0;
  93         int                     has_rmap;
  94         int                     error;
  95 
  96         if (info->whichfork == XFS_ATTR_FORK)
  97                 rflags |= XFS_RMAP_ATTR_FORK;
  98 
  99         /*
 100          * CoW staging extents are owned (on disk) by the refcountbt, so
 101          * their rmaps do not have offsets.
 102          */
 103         if (info->whichfork == XFS_COW_FORK)
 104                 offset = 0;
 105         else
 106                 offset = irec->br_startoff;
 107 
 108         /*
 109          * If the caller thinks this could be a shared bmbt extent (IOWs,
 110          * any data fork extent of a reflink inode) then we have to use the
 111          * range rmap lookup to make sure we get the correct owner/offset.
 112          */
 113         if (info->is_shared) {
 114                 error = xfs_rmap_lookup_le_range(info->sc->sa.rmap_cur, agbno,
 115                                 owner, offset, rflags, rmap, &has_rmap);
 116                 if (!xchk_should_check_xref(info->sc, &error,
 117                                 &info->sc->sa.rmap_cur))
 118                         return false;
 119                 goto out;
 120         }
 121 
 122         /*
 123          * Otherwise, use the (faster) regular lookup.
 124          */
 125         error = xfs_rmap_lookup_le(info->sc->sa.rmap_cur, agbno, 0, owner,
 126                         offset, rflags, &has_rmap);
 127         if (!xchk_should_check_xref(info->sc, &error,
 128                         &info->sc->sa.rmap_cur))
 129                 return false;
 130         if (!has_rmap)
 131                 goto out;
 132 
 133         error = xfs_rmap_get_rec(info->sc->sa.rmap_cur, rmap, &has_rmap);
 134         if (!xchk_should_check_xref(info->sc, &error,
 135                         &info->sc->sa.rmap_cur))
 136                 return false;
 137 
 138 out:
 139         if (!has_rmap)
 140                 xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
 141                         irec->br_startoff);
 142         return has_rmap;
 143 }
 144 
 145 /* Make sure that we have rmapbt records for this extent. */
 146 STATIC void
 147 xchk_bmap_xref_rmap(
 148         struct xchk_bmap_info   *info,
 149         struct xfs_bmbt_irec    *irec,
 150         xfs_agblock_t           agbno)
 151 {
 152         struct xfs_rmap_irec    rmap;
 153         unsigned long long      rmap_end;
 154         uint64_t                owner;
 155 
 156         if (!info->sc->sa.rmap_cur || xchk_skip_xref(info->sc->sm))
 157                 return;
 158 
 159         if (info->whichfork == XFS_COW_FORK)
 160                 owner = XFS_RMAP_OWN_COW;
 161         else
 162                 owner = info->sc->ip->i_ino;
 163 
 164         /* Find the rmap record for this irec. */
 165         if (!xchk_bmap_get_rmap(info, irec, agbno, owner, &rmap))
 166                 return;
 167 
 168         /* Check the rmap. */
 169         rmap_end = (unsigned long long)rmap.rm_startblock + rmap.rm_blockcount;
 170         if (rmap.rm_startblock > agbno ||
 171             agbno + irec->br_blockcount > rmap_end)
 172                 xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
 173                                 irec->br_startoff);
 174 
 175         /*
 176          * Check the logical offsets if applicable.  CoW staging extents
 177          * don't track logical offsets since the mappings only exist in
 178          * memory.
 179          */
 180         if (info->whichfork != XFS_COW_FORK) {
 181                 rmap_end = (unsigned long long)rmap.rm_offset +
 182                                 rmap.rm_blockcount;
 183                 if (rmap.rm_offset > irec->br_startoff ||
 184                     irec->br_startoff + irec->br_blockcount > rmap_end)
 185                         xchk_fblock_xref_set_corrupt(info->sc,
 186                                         info->whichfork, irec->br_startoff);
 187         }
 188 
 189         if (rmap.rm_owner != owner)
 190                 xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
 191                                 irec->br_startoff);
 192 
 193         /*
 194          * Check for discrepancies between the unwritten flag in the irec and
 195          * the rmap.  Note that the (in-memory) CoW fork distinguishes between
 196          * unwritten and written extents, but we don't track that in the rmap
 197          * records because the blocks are owned (on-disk) by the refcountbt,
 198          * which doesn't track unwritten state.
 199          */
 200         if (owner != XFS_RMAP_OWN_COW &&
 201             irec->br_state == XFS_EXT_UNWRITTEN &&
 202             !(rmap.rm_flags & XFS_RMAP_UNWRITTEN))
 203                 xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
 204                                 irec->br_startoff);
 205 
 206         if (info->whichfork == XFS_ATTR_FORK &&
 207             !(rmap.rm_flags & XFS_RMAP_ATTR_FORK))
 208                 xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
 209                                 irec->br_startoff);
 210         if (rmap.rm_flags & XFS_RMAP_BMBT_BLOCK)
 211                 xchk_fblock_xref_set_corrupt(info->sc, info->whichfork,
 212                                 irec->br_startoff);
 213 }
 214 
 215 /* Cross-reference a single rtdev extent record. */
 216 STATIC void
 217 xchk_bmap_rt_iextent_xref(
 218         struct xfs_inode        *ip,
 219         struct xchk_bmap_info   *info,
 220         struct xfs_bmbt_irec    *irec)
 221 {
 222         xchk_xref_is_used_rt_space(info->sc, irec->br_startblock,
 223                         irec->br_blockcount);
 224 }
 225 
 226 /* Cross-reference a single datadev extent record. */
 227 STATIC void
 228 xchk_bmap_iextent_xref(
 229         struct xfs_inode        *ip,
 230         struct xchk_bmap_info   *info,
 231         struct xfs_bmbt_irec    *irec)
 232 {
 233         struct xfs_mount        *mp = info->sc->mp;
 234         xfs_agnumber_t          agno;
 235         xfs_agblock_t           agbno;
 236         xfs_extlen_t            len;
 237         int                     error;
 238 
 239         agno = XFS_FSB_TO_AGNO(mp, irec->br_startblock);
 240         agbno = XFS_FSB_TO_AGBNO(mp, irec->br_startblock);
 241         len = irec->br_blockcount;
 242 
 243         error = xchk_ag_init(info->sc, agno, &info->sc->sa);
 244         if (!xchk_fblock_process_error(info->sc, info->whichfork,
 245                         irec->br_startoff, &error))
 246                 return;
 247 
 248         xchk_xref_is_used_space(info->sc, agbno, len);
 249         xchk_xref_is_not_inode_chunk(info->sc, agbno, len);
 250         xchk_bmap_xref_rmap(info, irec, agbno);
 251         switch (info->whichfork) {
 252         case XFS_DATA_FORK:
 253                 if (xfs_is_reflink_inode(info->sc->ip))
 254                         break;
 255                 /* fall through */
 256         case XFS_ATTR_FORK:
 257                 xchk_xref_is_not_shared(info->sc, agbno,
 258                                 irec->br_blockcount);
 259                 break;
 260         case XFS_COW_FORK:
 261                 xchk_xref_is_cow_staging(info->sc, agbno,
 262                                 irec->br_blockcount);
 263                 break;
 264         }
 265 
 266         xchk_ag_free(info->sc, &info->sc->sa);
 267 }
 268 
 269 /*
 270  * Directories and attr forks should never have blocks that can't be addressed
 271  * by a xfs_dablk_t.
 272  */
 273 STATIC void
 274 xchk_bmap_dirattr_extent(
 275         struct xfs_inode        *ip,
 276         struct xchk_bmap_info   *info,
 277         struct xfs_bmbt_irec    *irec)
 278 {
 279         struct xfs_mount        *mp = ip->i_mount;
 280         xfs_fileoff_t           off;
 281 
 282         if (!S_ISDIR(VFS_I(ip)->i_mode) && info->whichfork != XFS_ATTR_FORK)
 283                 return;
 284 
 285         if (!xfs_verify_dablk(mp, irec->br_startoff))
 286                 xchk_fblock_set_corrupt(info->sc, info->whichfork,
 287                                 irec->br_startoff);
 288 
 289         off = irec->br_startoff + irec->br_blockcount - 1;
 290         if (!xfs_verify_dablk(mp, off))
 291                 xchk_fblock_set_corrupt(info->sc, info->whichfork, off);
 292 }
 293 
 294 /* Scrub a single extent record. */
 295 STATIC int
 296 xchk_bmap_iextent(
 297         struct xfs_inode        *ip,
 298         struct xchk_bmap_info   *info,
 299         struct xfs_bmbt_irec    *irec)
 300 {
 301         struct xfs_mount        *mp = info->sc->mp;
 302         xfs_filblks_t           end;
 303         int                     error = 0;
 304 
 305         /*
 306          * Check for out-of-order extents.  This record could have come
 307          * from the incore list, for which there is no ordering check.
 308          */
 309         if (irec->br_startoff < info->lastoff)
 310                 xchk_fblock_set_corrupt(info->sc, info->whichfork,
 311                                 irec->br_startoff);
 312 
 313         xchk_bmap_dirattr_extent(ip, info, irec);
 314 
 315         /* There should never be a "hole" extent in either extent list. */
 316         if (irec->br_startblock == HOLESTARTBLOCK)
 317                 xchk_fblock_set_corrupt(info->sc, info->whichfork,
 318                                 irec->br_startoff);
 319 
 320         /*
 321          * Check for delalloc extents.  We never iterate the ones in the
 322          * in-core extent scan, and we should never see these in the bmbt.
 323          */
 324         if (isnullstartblock(irec->br_startblock))
 325                 xchk_fblock_set_corrupt(info->sc, info->whichfork,
 326                                 irec->br_startoff);
 327 
 328         /* Make sure the extent points to a valid place. */
 329         if (irec->br_blockcount > MAXEXTLEN)
 330                 xchk_fblock_set_corrupt(info->sc, info->whichfork,
 331                                 irec->br_startoff);
 332         if (irec->br_startblock + irec->br_blockcount <= irec->br_startblock)
 333                 xchk_fblock_set_corrupt(info->sc, info->whichfork,
 334                                 irec->br_startoff);
 335         end = irec->br_startblock + irec->br_blockcount - 1;
 336         if (info->is_rt &&
 337             (!xfs_verify_rtbno(mp, irec->br_startblock) ||
 338              !xfs_verify_rtbno(mp, end)))
 339                 xchk_fblock_set_corrupt(info->sc, info->whichfork,
 340                                 irec->br_startoff);
 341         if (!info->is_rt &&
 342             (!xfs_verify_fsbno(mp, irec->br_startblock) ||
 343              !xfs_verify_fsbno(mp, end) ||
 344              XFS_FSB_TO_AGNO(mp, irec->br_startblock) !=
 345                                 XFS_FSB_TO_AGNO(mp, end)))
 346                 xchk_fblock_set_corrupt(info->sc, info->whichfork,
 347                                 irec->br_startoff);
 348 
 349         /* We don't allow unwritten extents on attr forks. */
 350         if (irec->br_state == XFS_EXT_UNWRITTEN &&
 351             info->whichfork == XFS_ATTR_FORK)
 352                 xchk_fblock_set_corrupt(info->sc, info->whichfork,
 353                                 irec->br_startoff);
 354 
 355         if (info->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
 356                 return 0;
 357 
 358         if (info->is_rt)
 359                 xchk_bmap_rt_iextent_xref(ip, info, irec);
 360         else
 361                 xchk_bmap_iextent_xref(ip, info, irec);
 362 
 363         info->lastoff = irec->br_startoff + irec->br_blockcount;
 364         return error;
 365 }
 366 
 367 /* Scrub a bmbt record. */
 368 STATIC int
 369 xchk_bmapbt_rec(
 370         struct xchk_btree       *bs,
 371         union xfs_btree_rec     *rec)
 372 {
 373         struct xfs_bmbt_irec    irec;
 374         struct xfs_bmbt_irec    iext_irec;
 375         struct xfs_iext_cursor  icur;
 376         struct xchk_bmap_info   *info = bs->private;
 377         struct xfs_inode        *ip = bs->cur->bc_private.b.ip;
 378         struct xfs_buf          *bp = NULL;
 379         struct xfs_btree_block  *block;
 380         struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, info->whichfork);
 381         uint64_t                owner;
 382         int                     i;
 383 
 384         /*
 385          * Check the owners of the btree blocks up to the level below
 386          * the root since the verifiers don't do that.
 387          */
 388         if (xfs_sb_version_hascrc(&bs->cur->bc_mp->m_sb) &&
 389             bs->cur->bc_ptrs[0] == 1) {
 390                 for (i = 0; i < bs->cur->bc_nlevels - 1; i++) {
 391                         block = xfs_btree_get_block(bs->cur, i, &bp);
 392                         owner = be64_to_cpu(block->bb_u.l.bb_owner);
 393                         if (owner != ip->i_ino)
 394                                 xchk_fblock_set_corrupt(bs->sc,
 395                                                 info->whichfork, 0);
 396                 }
 397         }
 398 
 399         /*
 400          * Check that the incore extent tree contains an extent that matches
 401          * this one exactly.  We validate those cached bmaps later, so we don't
 402          * need to check them here.  If the incore extent tree was just loaded
 403          * from disk by the scrubber, we assume that its contents match what's
 404          * on disk (we still hold the ILOCK) and skip the equivalence check.
 405          */
 406         if (!info->was_loaded)
 407                 return 0;
 408 
 409         xfs_bmbt_disk_get_all(&rec->bmbt, &irec);
 410         if (!xfs_iext_lookup_extent(ip, ifp, irec.br_startoff, &icur,
 411                                 &iext_irec) ||
 412             irec.br_startoff != iext_irec.br_startoff ||
 413             irec.br_startblock != iext_irec.br_startblock ||
 414             irec.br_blockcount != iext_irec.br_blockcount ||
 415             irec.br_state != iext_irec.br_state)
 416                 xchk_fblock_set_corrupt(bs->sc, info->whichfork,
 417                                 irec.br_startoff);
 418         return 0;
 419 }
 420 
 421 /* Scan the btree records. */
 422 STATIC int
 423 xchk_bmap_btree(
 424         struct xfs_scrub        *sc,
 425         int                     whichfork,
 426         struct xchk_bmap_info   *info)
 427 {
 428         struct xfs_owner_info   oinfo;
 429         struct xfs_ifork        *ifp = XFS_IFORK_PTR(sc->ip, whichfork);
 430         struct xfs_mount        *mp = sc->mp;
 431         struct xfs_inode        *ip = sc->ip;
 432         struct xfs_btree_cur    *cur;
 433         int                     error;
 434 
 435         /* Load the incore bmap cache if it's not loaded. */
 436         info->was_loaded = ifp->if_flags & XFS_IFEXTENTS;
 437         if (!info->was_loaded) {
 438                 error = xfs_iread_extents(sc->tp, ip, whichfork);
 439                 if (!xchk_fblock_process_error(sc, whichfork, 0, &error))
 440                         goto out;
 441         }
 442 
 443         /* Check the btree structure. */
 444         cur = xfs_bmbt_init_cursor(mp, sc->tp, ip, whichfork);
 445         xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, whichfork);
 446         error = xchk_btree(sc, cur, xchk_bmapbt_rec, &oinfo, info);
 447         xfs_btree_del_cursor(cur, error);
 448 out:
 449         return error;
 450 }
 451 
 452 struct xchk_bmap_check_rmap_info {
 453         struct xfs_scrub        *sc;
 454         int                     whichfork;
 455         struct xfs_iext_cursor  icur;
 456 };
 457 
 458 /* Can we find bmaps that fit this rmap? */
 459 STATIC int
 460 xchk_bmap_check_rmap(
 461         struct xfs_btree_cur            *cur,
 462         struct xfs_rmap_irec            *rec,
 463         void                            *priv)
 464 {
 465         struct xfs_bmbt_irec            irec;
 466         struct xchk_bmap_check_rmap_info        *sbcri = priv;
 467         struct xfs_ifork                *ifp;
 468         struct xfs_scrub                *sc = sbcri->sc;
 469         bool                            have_map;
 470 
 471         /* Is this even the right fork? */
 472         if (rec->rm_owner != sc->ip->i_ino)
 473                 return 0;
 474         if ((sbcri->whichfork == XFS_ATTR_FORK) ^
 475             !!(rec->rm_flags & XFS_RMAP_ATTR_FORK))
 476                 return 0;
 477         if (rec->rm_flags & XFS_RMAP_BMBT_BLOCK)
 478                 return 0;
 479 
 480         /* Now look up the bmbt record. */
 481         ifp = XFS_IFORK_PTR(sc->ip, sbcri->whichfork);
 482         if (!ifp) {
 483                 xchk_fblock_set_corrupt(sc, sbcri->whichfork,
 484                                 rec->rm_offset);
 485                 goto out;
 486         }
 487         have_map = xfs_iext_lookup_extent(sc->ip, ifp, rec->rm_offset,
 488                         &sbcri->icur, &irec);
 489         if (!have_map)
 490                 xchk_fblock_set_corrupt(sc, sbcri->whichfork,
 491                                 rec->rm_offset);
 492         /*
 493          * bmap extent record lengths are constrained to 2^21 blocks in length
 494          * because of space constraints in the on-disk metadata structure.
 495          * However, rmap extent record lengths are constrained only by AG
 496          * length, so we have to loop through the bmbt to make sure that the
 497          * entire rmap is covered by bmbt records.
 498          */
 499         while (have_map) {
 500                 if (irec.br_startoff != rec->rm_offset)
 501                         xchk_fblock_set_corrupt(sc, sbcri->whichfork,
 502                                         rec->rm_offset);
 503                 if (irec.br_startblock != XFS_AGB_TO_FSB(sc->mp,
 504                                 cur->bc_private.a.agno, rec->rm_startblock))
 505                         xchk_fblock_set_corrupt(sc, sbcri->whichfork,
 506                                         rec->rm_offset);
 507                 if (irec.br_blockcount > rec->rm_blockcount)
 508                         xchk_fblock_set_corrupt(sc, sbcri->whichfork,
 509                                         rec->rm_offset);
 510                 if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
 511                         break;
 512                 rec->rm_startblock += irec.br_blockcount;
 513                 rec->rm_offset += irec.br_blockcount;
 514                 rec->rm_blockcount -= irec.br_blockcount;
 515                 if (rec->rm_blockcount == 0)
 516                         break;
 517                 have_map = xfs_iext_next_extent(ifp, &sbcri->icur, &irec);
 518                 if (!have_map)
 519                         xchk_fblock_set_corrupt(sc, sbcri->whichfork,
 520                                         rec->rm_offset);
 521         }
 522 
 523 out:
 524         if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
 525                 return -ECANCELED;
 526         return 0;
 527 }
 528 
 529 /* Make sure each rmap has a corresponding bmbt entry. */
 530 STATIC int
 531 xchk_bmap_check_ag_rmaps(
 532         struct xfs_scrub                *sc,
 533         int                             whichfork,
 534         xfs_agnumber_t                  agno)
 535 {
 536         struct xchk_bmap_check_rmap_info        sbcri;
 537         struct xfs_btree_cur            *cur;
 538         struct xfs_buf                  *agf;
 539         int                             error;
 540 
 541         error = xfs_alloc_read_agf(sc->mp, sc->tp, agno, 0, &agf);
 542         if (error)
 543                 return error;
 544 
 545         cur = xfs_rmapbt_init_cursor(sc->mp, sc->tp, agf, agno);
 546         if (!cur) {
 547                 error = -ENOMEM;
 548                 goto out_agf;
 549         }
 550 
 551         sbcri.sc = sc;
 552         sbcri.whichfork = whichfork;
 553         error = xfs_rmap_query_all(cur, xchk_bmap_check_rmap, &sbcri);
 554         if (error == -ECANCELED)
 555                 error = 0;
 556 
 557         xfs_btree_del_cursor(cur, error);
 558 out_agf:
 559         xfs_trans_brelse(sc->tp, agf);
 560         return error;
 561 }
 562 
 563 /* Make sure each rmap has a corresponding bmbt entry. */
 564 STATIC int
 565 xchk_bmap_check_rmaps(
 566         struct xfs_scrub        *sc,
 567         int                     whichfork)
 568 {
 569         loff_t                  size;
 570         xfs_agnumber_t          agno;
 571         int                     error;
 572 
 573         if (!xfs_sb_version_hasrmapbt(&sc->mp->m_sb) ||
 574             whichfork == XFS_COW_FORK ||
 575             (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
 576                 return 0;
 577 
 578         /* Don't support realtime rmap checks yet. */
 579         if (XFS_IS_REALTIME_INODE(sc->ip) && whichfork == XFS_DATA_FORK)
 580                 return 0;
 581 
 582         /*
 583          * Only do this for complex maps that are in btree format, or for
 584          * situations where we would seem to have a size but zero extents.
 585          * The inode repair code can zap broken iforks, which means we have
 586          * to flag this bmap as corrupt if there are rmaps that need to be
 587          * reattached.
 588          */
 589         switch (whichfork) {
 590         case XFS_DATA_FORK:
 591                 size = i_size_read(VFS_I(sc->ip));
 592                 break;
 593         case XFS_ATTR_FORK:
 594                 size = XFS_IFORK_Q(sc->ip);
 595                 break;
 596         default:
 597                 size = 0;
 598                 break;
 599         }
 600         if (XFS_IFORK_FORMAT(sc->ip, whichfork) != XFS_DINODE_FMT_BTREE &&
 601             (size == 0 || XFS_IFORK_NEXTENTS(sc->ip, whichfork) > 0))
 602                 return 0;
 603 
 604         for (agno = 0; agno < sc->mp->m_sb.sb_agcount; agno++) {
 605                 error = xchk_bmap_check_ag_rmaps(sc, whichfork, agno);
 606                 if (error)
 607                         return error;
 608                 if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
 609                         break;
 610         }
 611 
 612         return 0;
 613 }
 614 
 615 /*
 616  * Scrub an inode fork's block mappings.
 617  *
 618  * First we scan every record in every btree block, if applicable.
 619  * Then we unconditionally scan the incore extent cache.
 620  */
 621 STATIC int
 622 xchk_bmap(
 623         struct xfs_scrub        *sc,
 624         int                     whichfork)
 625 {
 626         struct xfs_bmbt_irec    irec;
 627         struct xchk_bmap_info   info = { NULL };
 628         struct xfs_mount        *mp = sc->mp;
 629         struct xfs_inode        *ip = sc->ip;
 630         struct xfs_ifork        *ifp;
 631         xfs_fileoff_t           endoff;
 632         struct xfs_iext_cursor  icur;
 633         int                     error = 0;
 634 
 635         ifp = XFS_IFORK_PTR(ip, whichfork);
 636 
 637         info.is_rt = whichfork == XFS_DATA_FORK && XFS_IS_REALTIME_INODE(ip);
 638         info.whichfork = whichfork;
 639         info.is_shared = whichfork == XFS_DATA_FORK && xfs_is_reflink_inode(ip);
 640         info.sc = sc;
 641 
 642         switch (whichfork) {
 643         case XFS_COW_FORK:
 644                 /* Non-existent CoW forks are ignorable. */
 645                 if (!ifp)
 646                         goto out;
 647                 /* No CoW forks on non-reflink inodes/filesystems. */
 648                 if (!xfs_is_reflink_inode(ip)) {
 649                         xchk_ino_set_corrupt(sc, sc->ip->i_ino);
 650                         goto out;
 651                 }
 652                 break;
 653         case XFS_ATTR_FORK:
 654                 if (!ifp)
 655                         goto out_check_rmap;
 656                 if (!xfs_sb_version_hasattr(&mp->m_sb) &&
 657                     !xfs_sb_version_hasattr2(&mp->m_sb))
 658                         xchk_ino_set_corrupt(sc, sc->ip->i_ino);
 659                 break;
 660         default:
 661                 ASSERT(whichfork == XFS_DATA_FORK);
 662                 break;
 663         }
 664 
 665         /* Check the fork values */
 666         switch (XFS_IFORK_FORMAT(ip, whichfork)) {
 667         case XFS_DINODE_FMT_UUID:
 668         case XFS_DINODE_FMT_DEV:
 669         case XFS_DINODE_FMT_LOCAL:
 670                 /* No mappings to check. */
 671                 goto out;
 672         case XFS_DINODE_FMT_EXTENTS:
 673                 if (!(ifp->if_flags & XFS_IFEXTENTS)) {
 674                         xchk_fblock_set_corrupt(sc, whichfork, 0);
 675                         goto out;
 676                 }
 677                 break;
 678         case XFS_DINODE_FMT_BTREE:
 679                 if (whichfork == XFS_COW_FORK) {
 680                         xchk_fblock_set_corrupt(sc, whichfork, 0);
 681                         goto out;
 682                 }
 683 
 684                 error = xchk_bmap_btree(sc, whichfork, &info);
 685                 if (error)
 686                         goto out;
 687                 break;
 688         default:
 689                 xchk_fblock_set_corrupt(sc, whichfork, 0);
 690                 goto out;
 691         }
 692 
 693         if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
 694                 goto out;
 695 
 696         /* Find the offset of the last extent in the mapping. */
 697         error = xfs_bmap_last_offset(ip, &endoff, whichfork);
 698         if (!xchk_fblock_process_error(sc, whichfork, 0, &error))
 699                 goto out;
 700 
 701         /* Scrub extent records. */
 702         info.lastoff = 0;
 703         ifp = XFS_IFORK_PTR(ip, whichfork);
 704         for_each_xfs_iext(ifp, &icur, &irec) {
 705                 if (xchk_should_terminate(sc, &error) ||
 706                     (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
 707                         goto out;
 708                 if (isnullstartblock(irec.br_startblock))
 709                         continue;
 710                 if (irec.br_startoff >= endoff) {
 711                         xchk_fblock_set_corrupt(sc, whichfork,
 712                                         irec.br_startoff);
 713                         goto out;
 714                 }
 715                 error = xchk_bmap_iextent(ip, &info, &irec);
 716                 if (error)
 717                         goto out;
 718         }
 719 
 720 out_check_rmap:
 721         error = xchk_bmap_check_rmaps(sc, whichfork);
 722         if (!xchk_fblock_xref_process_error(sc, whichfork, 0, &error))
 723                 goto out;
 724 out:
 725         return error;
 726 }
 727 
 728 /* Scrub an inode's data fork. */
 729 int
 730 xchk_bmap_data(
 731         struct xfs_scrub        *sc)
 732 {
 733         return xchk_bmap(sc, XFS_DATA_FORK);
 734 }
 735 
 736 /* Scrub an inode's attr fork. */
 737 int
 738 xchk_bmap_attr(
 739         struct xfs_scrub        *sc)
 740 {
 741         return xchk_bmap(sc, XFS_ATTR_FORK);
 742 }
 743 
 744 /* Scrub an inode's CoW fork. */
 745 int
 746 xchk_bmap_cow(
 747         struct xfs_scrub        *sc)
 748 {
 749         if (!xfs_is_reflink_inode(sc->ip))
 750                 return -ENOENT;
 751 
 752         return xchk_bmap(sc, XFS_COW_FORK);
 753 }