fs/xfs/scrub/dabtree.c

   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_log_format.h"
  13 #include "xfs_trans.h"
  14 #include "xfs_inode.h"
  15 #include "xfs_dir2.h"
  16 #include "xfs_dir2_priv.h"
  17 #include "xfs_attr_leaf.h"
  18 #include "scrub/scrub.h"
  19 #include "scrub/common.h"
  20 #include "scrub/trace.h"
  21 #include "scrub/dabtree.h"
  22
  23 /* Directory/Attribute Btree */
  24
  25 /*
  26  * Check for da btree operation errors.  See the section about handling
  27  * operational errors in common.c.
  28  */
  29 bool
  30 xchk_da_process_error(
  31         struct xchk_da_btree    *ds,
  32         int                     level,
  33         int                     *error)
  34 {
  35         struct xfs_scrub        *sc = ds->sc;
  36
  37         if (*error == 0)
  38                 return true;
  39
  40         switch (*error) {
  41         case -EDEADLOCK:
  42                 /* Used to restart an op with deadlock avoidance. */
  43                 trace_xchk_deadlock_retry(sc->ip, sc->sm, *error);
  44                 break;
  45         case -EFSBADCRC:
  46         case -EFSCORRUPTED:
  47                 /* Note the badness but don't abort. */
  48                 sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
  49                 *error = 0;
  50                 /* fall through */
  51         default:
  52                 trace_xchk_file_op_error(sc, ds->dargs.whichfork,
  53                                 xfs_dir2_da_to_db(ds->dargs.geo,
  54                                         ds->state->path.blk[level].blkno),
  55                                 *error, __return_address);
  56                 break;
  57         }
  58         return false;
  59 }
  60
  61 /*
  62  * Check for da btree corruption.  See the section about handling
  63  * operational errors in common.c.
  64  */
  65 void
  66 xchk_da_set_corrupt(
  67         struct xchk_da_btree    *ds,
  68         int                     level)
  69 {
  70         struct xfs_scrub        *sc = ds->sc;
  71
  72         sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
  73
  74         trace_xchk_fblock_error(sc, ds->dargs.whichfork,
  75                         xfs_dir2_da_to_db(ds->dargs.geo,
  76                                 ds->state->path.blk[level].blkno),
  77                         __return_address);
  78 }
  79
  80 static struct xfs_da_node_entry *
  81 xchk_da_btree_node_entry(
  82         struct xchk_da_btree            *ds,
  83         int                             level)
  84 {
  85         struct xfs_da_state_blk         *blk = &ds->state->path.blk[level];
  86         struct xfs_da3_icnode_hdr       hdr;
  87
  88         ASSERT(blk->magic == XFS_DA_NODE_MAGIC);
  89
  90         xfs_da3_node_hdr_from_disk(ds->sc->mp, &hdr, blk->bp->b_addr);
  91         return hdr.btree + blk->index;
  92 }
  93
  94 /* Scrub a da btree hash (key). */
  95 int
  96 xchk_da_btree_hash(
  97         struct xchk_da_btree            *ds,
  98         int                             level,
  99         __be32                          *hashp)
 100 {
 101         struct xfs_da_node_entry        *entry;
 102         xfs_dahash_t                    hash;
 103         xfs_dahash_t                    parent_hash;
 104
 105         /* Is this hash in order? */
 106         hash = be32_to_cpu(*hashp);
 107         if (hash < ds->hashes[level])
 108                 xchk_da_set_corrupt(ds, level);
 109         ds->hashes[level] = hash;
 110
 111         if (level == 0)
 112                 return 0;
 113
 114         /* Is this hash no larger than the parent hash? */
 115         entry = xchk_da_btree_node_entry(ds, level - 1);
 116         parent_hash = be32_to_cpu(entry->hashval);
 117         if (parent_hash < hash)
 118                 xchk_da_set_corrupt(ds, level);
 119
 120         return 0;
 121 }
 122
 123 /*
 124  * Check a da btree pointer.  Returns true if it's ok to use this
 125  * pointer.
 126  */
 127 STATIC bool
 128 xchk_da_btree_ptr_ok(
 129         struct xchk_da_btree    *ds,
 130         int                     level,
 131         xfs_dablk_t             blkno)
 132 {
 133         if (blkno < ds->lowest || (ds->highest != 0 && blkno >= ds->highest)) {
 134                 xchk_da_set_corrupt(ds, level);
 135                 return false;
 136         }
 137
 138         return true;
 139 }
 140
 141 /*
 142  * The da btree scrubber can handle leaf1 blocks as a degenerate
 143  * form of leafn blocks.  Since the regular da code doesn't handle
 144  * leaf1, we must multiplex the verifiers.
 145  */
 146 static void
 147 xchk_da_btree_read_verify(
 148         struct xfs_buf          *bp)
 149 {
 150         struct xfs_da_blkinfo   *info = bp->b_addr;
 151
 152         switch (be16_to_cpu(info->magic)) {
 153         case XFS_DIR2_LEAF1_MAGIC:
 154         case XFS_DIR3_LEAF1_MAGIC:
 155                 bp->b_ops = &xfs_dir3_leaf1_buf_ops;
 156                 bp->b_ops->verify_read(bp);
 157                 return;
 158         default:
 159                 /*
 160                  * xfs_da3_node_buf_ops already know how to handle
 161                  * DA*_NODE, ATTR*_LEAF, and DIR*_LEAFN blocks.
 162                  */
 163                 bp->b_ops = &xfs_da3_node_buf_ops;
 164                 bp->b_ops->verify_read(bp);
 165                 return;
 166         }
 167 }
 168 static void
 169 xchk_da_btree_write_verify(
 170         struct xfs_buf          *bp)
 171 {
 172         struct xfs_da_blkinfo   *info = bp->b_addr;
 173
 174         switch (be16_to_cpu(info->magic)) {
 175         case XFS_DIR2_LEAF1_MAGIC:
 176         case XFS_DIR3_LEAF1_MAGIC:
 177                 bp->b_ops = &xfs_dir3_leaf1_buf_ops;
 178                 bp->b_ops->verify_write(bp);
 179                 return;
 180         default:
 181                 /*
 182                  * xfs_da3_node_buf_ops already know how to handle
 183                  * DA*_NODE, ATTR*_LEAF, and DIR*_LEAFN blocks.
 184                  */
 185                 bp->b_ops = &xfs_da3_node_buf_ops;
 186                 bp->b_ops->verify_write(bp);
 187                 return;
 188         }
 189 }
 190 static void *
 191 xchk_da_btree_verify(
 192         struct xfs_buf          *bp)
 193 {
 194         struct xfs_da_blkinfo   *info = bp->b_addr;
 195
 196         switch (be16_to_cpu(info->magic)) {
 197         case XFS_DIR2_LEAF1_MAGIC:
 198         case XFS_DIR3_LEAF1_MAGIC:
 199                 bp->b_ops = &xfs_dir3_leaf1_buf_ops;
 200                 return bp->b_ops->verify_struct(bp);
 201         default:
 202                 bp->b_ops = &xfs_da3_node_buf_ops;
 203                 return bp->b_ops->verify_struct(bp);
 204         }
 205 }
 206
 207 static const struct xfs_buf_ops xchk_da_btree_buf_ops = {
 208         .name = "xchk_da_btree",
 209         .verify_read = xchk_da_btree_read_verify,
 210         .verify_write = xchk_da_btree_write_verify,
 211         .verify_struct = xchk_da_btree_verify,
 212 };
 213
 214 /* Check a block's sibling. */
 215 STATIC int
 216 xchk_da_btree_block_check_sibling(
 217         struct xchk_da_btree    *ds,
 218         int                     level,
 219         int                     direction,
 220         xfs_dablk_t             sibling)
 221 {
 222         int                     retval;
 223         int                     error;
 224
 225         memcpy(&ds->state->altpath, &ds->state->path,
 226                         sizeof(ds->state->altpath));
 227
 228         /*
 229          * If the pointer is null, we shouldn't be able to move the upper
 230          * level pointer anywhere.
 231          */
 232         if (sibling == 0) {
 233                 error = xfs_da3_path_shift(ds->state, &ds->state->altpath,
 234                                 direction, false, &retval);
 235                 if (error == 0 && retval == 0)
 236                         xchk_da_set_corrupt(ds, level);
 237                 error = 0;
 238                 goto out;
 239         }
 240
 241         /* Move the alternate cursor one block in the direction given. */
 242         error = xfs_da3_path_shift(ds->state, &ds->state->altpath,
 243                         direction, false, &retval);
 244         if (!xchk_da_process_error(ds, level, &error))
 245                 return error;
 246         if (retval) {
 247                 xchk_da_set_corrupt(ds, level);
 248                 return error;
 249         }
 250         if (ds->state->altpath.blk[level].bp)
 251                 xchk_buffer_recheck(ds->sc,
 252                                 ds->state->altpath.blk[level].bp);
 253
 254         /* Compare upper level pointer to sibling pointer. */
 255         if (ds->state->altpath.blk[level].blkno != sibling)
 256                 xchk_da_set_corrupt(ds, level);
 257         if (ds->state->altpath.blk[level].bp) {
 258                 xfs_trans_brelse(ds->dargs.trans,
 259                                 ds->state->altpath.blk[level].bp);
 260                 ds->state->altpath.blk[level].bp = NULL;
 261         }
 262 out:
 263         return error;
 264 }
 265
 266 /* Check a block's sibling pointers. */
 267 STATIC int
 268 xchk_da_btree_block_check_siblings(
 269         struct xchk_da_btree    *ds,
 270         int                     level,
 271         struct xfs_da_blkinfo   *hdr)
 272 {
 273         xfs_dablk_t             forw;
 274         xfs_dablk_t             back;
 275         int                     error = 0;
 276
 277         forw = be32_to_cpu(hdr->forw);
 278         back = be32_to_cpu(hdr->back);
 279
 280         /* Top level blocks should not have sibling pointers. */
 281         if (level == 0) {
 282                 if (forw != 0 || back != 0)
 283                         xchk_da_set_corrupt(ds, level);
 284                 return 0;
 285         }
 286
 287         /*
 288          * Check back (left) and forw (right) pointers.  These functions
 289          * absorb error codes for us.
 290          */
 291         error = xchk_da_btree_block_check_sibling(ds, level, 0, back);
 292         if (error)
 293                 goto out;
 294         error = xchk_da_btree_block_check_sibling(ds, level, 1, forw);
 295
 296 out:
 297         memset(&ds->state->altpath, 0, sizeof(ds->state->altpath));
 298         return error;
 299 }
 300
 301 /* Load a dir/attribute block from a btree. */
 302 STATIC int
 303 xchk_da_btree_block(
 304         struct xchk_da_btree            *ds,
 305         int                             level,
 306         xfs_dablk_t                     blkno)
 307 {
 308         struct xfs_da_state_blk         *blk;
 309         struct xfs_da_intnode           *node;
 310         struct xfs_da_node_entry        *btree;
 311         struct xfs_da3_blkinfo          *hdr3;
 312         struct xfs_da_args              *dargs = &ds->dargs;
 313         struct xfs_inode                *ip = ds->dargs.dp;
 314         xfs_ino_t                       owner;
 315         int                             *pmaxrecs;
 316         struct xfs_da3_icnode_hdr       nodehdr;
 317         int                             error = 0;
 318
 319         blk = &ds->state->path.blk[level];
 320         ds->state->path.active = level + 1;
 321
 322         /* Release old block. */
 323         if (blk->bp) {
 324                 xfs_trans_brelse(dargs->trans, blk->bp);
 325                 blk->bp = NULL;
 326         }
 327
 328         /* Check the pointer. */
 329         blk->blkno = blkno;
 330         if (!xchk_da_btree_ptr_ok(ds, level, blkno))
 331                 goto out_nobuf;
 332
 333         /* Read the buffer. */
 334         error = xfs_da_read_buf(dargs->trans, dargs->dp, blk->blkno,
 335                         XFS_DABUF_MAP_HOLE_OK, &blk->bp, dargs->whichfork,
 336                         &xchk_da_btree_buf_ops);
 337         if (!xchk_da_process_error(ds, level, &error))
 338                 goto out_nobuf;
 339         if (blk->bp)
 340                 xchk_buffer_recheck(ds->sc, blk->bp);
 341
 342         /*
 343          * We didn't find a dir btree root block, which means that
 344          * there's no LEAF1/LEAFN tree (at least not where it's supposed
 345          * to be), so jump out now.
 346          */
 347         if (ds->dargs.whichfork == XFS_DATA_FORK && level == 0 &&
 348                         blk->bp == NULL)
 349                 goto out_nobuf;
 350
 351         /* It's /not/ ok for attr trees not to have a da btree. */
 352         if (blk->bp == NULL) {
 353                 xchk_da_set_corrupt(ds, level);
 354                 goto out_nobuf;
 355         }
 356
 357         hdr3 = blk->bp->b_addr;
 358         blk->magic = be16_to_cpu(hdr3->hdr.magic);
 359         pmaxrecs = &ds->maxrecs[level];
 360
 361         /* We only started zeroing the header on v5 filesystems. */
 362         if (xfs_sb_version_hascrc(&ds->sc->mp->m_sb) && hdr3->hdr.pad)
 363                 xchk_da_set_corrupt(ds, level);
 364
 365         /* Check the owner. */
 366         if (xfs_sb_version_hascrc(&ip->i_mount->m_sb)) {
 367                 owner = be64_to_cpu(hdr3->owner);
 368                 if (owner != ip->i_ino)
 369                         xchk_da_set_corrupt(ds, level);
 370         }
 371
 372         /* Check the siblings. */
 373         error = xchk_da_btree_block_check_siblings(ds, level, &hdr3->hdr);
 374         if (error)
 375                 goto out;
 376
 377         /* Interpret the buffer. */
 378         switch (blk->magic) {
 379         case XFS_ATTR_LEAF_MAGIC:
 380         case XFS_ATTR3_LEAF_MAGIC:
 381                 xfs_trans_buf_set_type(dargs->trans, blk->bp,
 382                                 XFS_BLFT_ATTR_LEAF_BUF);
 383                 blk->magic = XFS_ATTR_LEAF_MAGIC;
 384                 blk->hashval = xfs_attr_leaf_lasthash(blk->bp, pmaxrecs);
 385                 if (ds->tree_level != 0)
 386                         xchk_da_set_corrupt(ds, level);
 387                 break;
 388         case XFS_DIR2_LEAFN_MAGIC:
 389         case XFS_DIR3_LEAFN_MAGIC:
 390                 xfs_trans_buf_set_type(dargs->trans, blk->bp,
 391                                 XFS_BLFT_DIR_LEAFN_BUF);
 392                 blk->magic = XFS_DIR2_LEAFN_MAGIC;
 393                 blk->hashval = xfs_dir2_leaf_lasthash(ip, blk->bp, pmaxrecs);
 394                 if (ds->tree_level != 0)
 395                         xchk_da_set_corrupt(ds, level);
 396                 break;
 397         case XFS_DIR2_LEAF1_MAGIC:
 398         case XFS_DIR3_LEAF1_MAGIC:
 399                 xfs_trans_buf_set_type(dargs->trans, blk->bp,
 400                                 XFS_BLFT_DIR_LEAF1_BUF);
 401                 blk->magic = XFS_DIR2_LEAF1_MAGIC;
 402                 blk->hashval = xfs_dir2_leaf_lasthash(ip, blk->bp, pmaxrecs);
 403                 if (ds->tree_level != 0)
 404                         xchk_da_set_corrupt(ds, level);
 405                 break;
 406         case XFS_DA_NODE_MAGIC:
 407         case XFS_DA3_NODE_MAGIC:
 408                 xfs_trans_buf_set_type(dargs->trans, blk->bp,
 409                                 XFS_BLFT_DA_NODE_BUF);
 410                 blk->magic = XFS_DA_NODE_MAGIC;
 411                 node = blk->bp->b_addr;
 412                 xfs_da3_node_hdr_from_disk(ip->i_mount, &nodehdr, node);
 413                 btree = nodehdr.btree;
 414                 *pmaxrecs = nodehdr.count;
 415                 blk->hashval = be32_to_cpu(btree[*pmaxrecs - 1].hashval);
 416                 if (level == 0) {
 417                         if (nodehdr.level >= XFS_DA_NODE_MAXDEPTH) {
 418                                 xchk_da_set_corrupt(ds, level);
 419                                 goto out_freebp;
 420                         }
 421                         ds->tree_level = nodehdr.level;
 422                 } else {
 423                         if (ds->tree_level != nodehdr.level) {
 424                                 xchk_da_set_corrupt(ds, level);
 425                                 goto out_freebp;
 426                         }
 427                 }
 428
 429                 /* XXX: Check hdr3.pad32 once we know how to fix it. */
 430                 break;
 431         default:
 432                 xchk_da_set_corrupt(ds, level);
 433                 goto out_freebp;
 434         }
 435
 436 out:
 437         return error;
 438 out_freebp:
 439         xfs_trans_brelse(dargs->trans, blk->bp);
 440         blk->bp = NULL;
 441 out_nobuf:
 442         blk->blkno = 0;
 443         return error;
 444 }
 445
 446 /* Visit all nodes and leaves of a da btree. */
 447 int
 448 xchk_da_btree(
 449         struct xfs_scrub                *sc,
 450         int                             whichfork,
 451         xchk_da_btree_rec_fn            scrub_fn,
 452         void                            *private)
 453 {
 454         struct xchk_da_btree            ds = {};
 455         struct xfs_mount                *mp = sc->mp;
 456         struct xfs_da_state_blk         *blks;
 457         struct xfs_da_node_entry        *key;
 458         xfs_dablk_t                     blkno;
 459         int                             level;
 460         int                             error;
 461
 462         /* Skip short format data structures; no btree to scan. */
 463         if (!xfs_ifork_has_extents(sc->ip, whichfork))
 464                 return 0;
 465
 466         /* Set up initial da state. */
 467         ds.dargs.dp = sc->ip;
 468         ds.dargs.whichfork = whichfork;
 469         ds.dargs.trans = sc->tp;
 470         ds.dargs.op_flags = XFS_DA_OP_OKNOENT;
 471         ds.state = xfs_da_state_alloc();
 472         ds.state->args = &ds.dargs;
 473         ds.state->mp = mp;
 474         ds.sc = sc;
 475         ds.private = private;
 476         if (whichfork == XFS_ATTR_FORK) {
 477                 ds.dargs.geo = mp->m_attr_geo;
 478                 ds.lowest = 0;
 479                 ds.highest = 0;
 480         } else {
 481                 ds.dargs.geo = mp->m_dir_geo;
 482                 ds.lowest = ds.dargs.geo->leafblk;
 483                 ds.highest = ds.dargs.geo->freeblk;
 484         }
 485         blkno = ds.lowest;
 486         level = 0;
 487
 488         /* Find the root of the da tree, if present. */
 489         blks = ds.state->path.blk;
 490         error = xchk_da_btree_block(&ds, level, blkno);
 491         if (error)
 492                 goto out_state;
 493         /*
 494          * We didn't find a block at ds.lowest, which means that there's
 495          * no LEAF1/LEAFN tree (at least not where it's supposed to be),
 496          * so jump out now.
 497          */
 498         if (blks[level].bp == NULL)
 499                 goto out_state;
 500
 501         blks[level].index = 0;
 502         while (level >= 0 && level < XFS_DA_NODE_MAXDEPTH) {
 503                 /* Handle leaf block. */
 504                 if (blks[level].magic != XFS_DA_NODE_MAGIC) {
 505                         /* End of leaf, pop back towards the root. */
 506                         if (blks[level].index >= ds.maxrecs[level]) {
 507                                 if (level > 0)
 508                                         blks[level - 1].index++;
 509                                 ds.tree_level++;
 510                                 level--;
 511                                 continue;
 512                         }
 513
 514                         /* Dispatch record scrubbing. */
 515                         error = scrub_fn(&ds, level);
 516                         if (error)
 517                                 break;
 518                         if (xchk_should_terminate(sc, &error) ||
 519                             (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
 520                                 break;
 521
 522                         blks[level].index++;
 523                         continue;
 524                 }
 525
 526
 527                 /* End of node, pop back towards the root. */
 528                 if (blks[level].index >= ds.maxrecs[level]) {
 529                         if (level > 0)
 530                                 blks[level - 1].index++;
 531                         ds.tree_level++;
 532                         level--;
 533                         continue;
 534                 }
 535
 536                 /* Hashes in order for scrub? */
 537                 key = xchk_da_btree_node_entry(&ds, level);
 538                 error = xchk_da_btree_hash(&ds, level, &key->hashval);
 539                 if (error)
 540                         goto out;
 541
 542                 /* Drill another level deeper. */
 543                 blkno = be32_to_cpu(key->before);
 544                 level++;
 545                 if (level >= XFS_DA_NODE_MAXDEPTH) {
 546                         /* Too deep! */
 547                         xchk_da_set_corrupt(&ds, level - 1);
 548                         break;
 549                 }
 550                 ds.tree_level--;
 551                 error = xchk_da_btree_block(&ds, level, blkno);
 552                 if (error)
 553                         goto out;
 554                 if (blks[level].bp == NULL)
 555                         goto out;
 556
 557                 blks[level].index = 0;
 558         }
 559
 560 out:
 561         /* Release all the buffers we're tracking. */
 562         for (level = 0; level < XFS_DA_NODE_MAXDEPTH; level++) {
 563                 if (blks[level].bp == NULL)
 564                         continue;
 565                 xfs_trans_brelse(sc->tp, blks[level].bp);
 566                 blks[level].bp = NULL;
 567         }
 568
 569 out_state:
 570         xfs_da_state_free(ds.state);
 571         return error;
 572 }