fs/ubifs/orphan.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * This file is part of UBIFS.
   4  *
   5  * Copyright (C) 2006-2008 Nokia Corporation.
   6  *
   7  * Author: Adrian Hunter
   8  */
   9
  10 #include "ubifs.h"
  11
  12 /*
  13  * An orphan is an inode number whose inode node has been committed to the index
  14  * with a link count of zero. That happens when an open file is deleted
  15  * (unlinked) and then a commit is run. In the normal course of events the inode
  16  * would be deleted when the file is closed. However in the case of an unclean
  17  * unmount, orphans need to be accounted for. After an unclean unmount, the
  18  * orphans' inodes must be deleted which means either scanning the entire index
  19  * looking for them, or keeping a list on flash somewhere. This unit implements
  20  * the latter approach.
  21  *
  22  * The orphan area is a fixed number of LEBs situated between the LPT area and
  23  * the main area. The number of orphan area LEBs is specified when the file
  24  * system is created. The minimum number is 1. The size of the orphan area
  25  * should be so that it can hold the maximum number of orphans that are expected
  26  * to ever exist at one time.
  27  *
  28  * The number of orphans that can fit in a LEB is:
  29  *
  30  *         (c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64)
  31  *
  32  * For example: a 15872 byte LEB can fit 1980 orphans so 1 LEB may be enough.
  33  *
  34  * Orphans are accumulated in a rb-tree. When an inode's link count drops to
  35  * zero, the inode number is added to the rb-tree. It is removed from the tree
  36  * when the inode is deleted.  Any new orphans that are in the orphan tree when
  37  * the commit is run, are written to the orphan area in 1 or more orphan nodes.
  38  * If the orphan area is full, it is consolidated to make space.  There is
  39  * always enough space because validation prevents the user from creating more
  40  * than the maximum number of orphans allowed.
  41  */
  42
  43 static int dbg_check_orphans(struct ubifs_info *c);
  44
  45 static struct ubifs_orphan *orphan_add(struct ubifs_info *c, ino_t inum,
  46                                        struct ubifs_orphan *parent_orphan)
  47 {
  48         struct ubifs_orphan *orphan, *o;
  49         struct rb_node **p, *parent = NULL;
  50
  51         orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_NOFS);
  52         if (!orphan)
  53                 return ERR_PTR(-ENOMEM);
  54         orphan->inum = inum;
  55         orphan->new = 1;
  56         INIT_LIST_HEAD(&orphan->child_list);
  57
  58         spin_lock(&c->orphan_lock);
  59         if (c->tot_orphans >= c->max_orphans) {
  60                 spin_unlock(&c->orphan_lock);
  61                 kfree(orphan);
  62                 return ERR_PTR(-ENFILE);
  63         }
  64         p = &c->orph_tree.rb_node;
  65         while (*p) {
  66                 parent = *p;
  67                 o = rb_entry(parent, struct ubifs_orphan, rb);
  68                 if (inum < o->inum)
  69                         p = &(*p)->rb_left;
  70                 else if (inum > o->inum)
  71                         p = &(*p)->rb_right;
  72                 else {
  73                         ubifs_err(c, "orphaned twice");
  74                         spin_unlock(&c->orphan_lock);
  75                         kfree(orphan);
  76                         return ERR_PTR(-EINVAL);
  77                 }
  78         }
  79         c->tot_orphans += 1;
  80         c->new_orphans += 1;
  81         rb_link_node(&orphan->rb, parent, p);
  82         rb_insert_color(&orphan->rb, &c->orph_tree);
  83         list_add_tail(&orphan->list, &c->orph_list);
  84         list_add_tail(&orphan->new_list, &c->orph_new);
  85
  86         if (parent_orphan) {
  87                 list_add_tail(&orphan->child_list,
  88                               &parent_orphan->child_list);
  89         }
  90
  91         spin_unlock(&c->orphan_lock);
  92         dbg_gen("ino %lu", (unsigned long)inum);
  93         return orphan;
  94 }
  95
  96 static struct ubifs_orphan *lookup_orphan(struct ubifs_info *c, ino_t inum)
  97 {
  98         struct ubifs_orphan *o;
  99         struct rb_node *p;
 100
 101         p = c->orph_tree.rb_node;
 102         while (p) {
 103                 o = rb_entry(p, struct ubifs_orphan, rb);
 104                 if (inum < o->inum)
 105                         p = p->rb_left;
 106                 else if (inum > o->inum)
 107                         p = p->rb_right;
 108                 else {
 109                         return o;
 110                 }
 111         }
 112         return NULL;
 113 }
 114
 115 static void __orphan_drop(struct ubifs_info *c, struct ubifs_orphan *o)
 116 {
 117         rb_erase(&o->rb, &c->orph_tree);
 118         list_del(&o->list);
 119         c->tot_orphans -= 1;
 120
 121         if (o->new) {
 122                 list_del(&o->new_list);
 123                 c->new_orphans -= 1;
 124         }
 125
 126         kfree(o);
 127 }
 128
 129 static void orphan_delete(struct ubifs_info *c, struct ubifs_orphan *orph)
 130 {
 131         if (orph->del) {
 132                 dbg_gen("deleted twice ino %lu", (unsigned long)orph->inum);
 133                 return;
 134         }
 135
 136         if (orph->cmt) {
 137                 orph->del = 1;
 138                 orph->dnext = c->orph_dnext;
 139                 c->orph_dnext = orph;
 140                 dbg_gen("delete later ino %lu", (unsigned long)orph->inum);
 141                 return;
 142         }
 143
 144         __orphan_drop(c, orph);
 145 }
 146
 147 /**
 148  * ubifs_add_orphan - add an orphan.
 149  * @c: UBIFS file-system description object
 150  * @inum: orphan inode number
 151  *
 152  * Add an orphan. This function is called when an inodes link count drops to
 153  * zero.
 154  */
 155 int ubifs_add_orphan(struct ubifs_info *c, ino_t inum)
 156 {
 157         int err = 0;
 158         ino_t xattr_inum;
 159         union ubifs_key key;
 160         struct ubifs_dent_node *xent;
 161         struct fscrypt_name nm = {0};
 162         struct ubifs_orphan *xattr_orphan;
 163         struct ubifs_orphan *orphan;
 164
 165         orphan = orphan_add(c, inum, NULL);
 166         if (IS_ERR(orphan))
 167                 return PTR_ERR(orphan);
 168
 169         lowest_xent_key(c, &key, inum);
 170         while (1) {
 171                 xent = ubifs_tnc_next_ent(c, &key, &nm);
 172                 if (IS_ERR(xent)) {
 173                         err = PTR_ERR(xent);
 174                         if (err == -ENOENT)
 175                                 break;
 176                         return err;
 177                 }
 178
 179                 fname_name(&nm) = xent->name;
 180                 fname_len(&nm) = le16_to_cpu(xent->nlen);
 181                 xattr_inum = le64_to_cpu(xent->inum);
 182
 183                 xattr_orphan = orphan_add(c, xattr_inum, orphan);
 184                 if (IS_ERR(xattr_orphan))
 185                         return PTR_ERR(xattr_orphan);
 186
 187                 key_read(c, &xent->key, &key);
 188         }
 189
 190         return 0;
 191 }
 192
 193 /**
 194  * ubifs_delete_orphan - delete an orphan.
 195  * @c: UBIFS file-system description object
 196  * @inum: orphan inode number
 197  *
 198  * Delete an orphan. This function is called when an inode is deleted.
 199  */
 200 void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
 201 {
 202         struct ubifs_orphan *orph, *child_orph, *tmp_o;
 203
 204         spin_lock(&c->orphan_lock);
 205
 206         orph = lookup_orphan(c, inum);
 207         if (!orph) {
 208                 spin_unlock(&c->orphan_lock);
 209                 ubifs_err(c, "missing orphan ino %lu", (unsigned long)inum);
 210                 dump_stack();
 211
 212                 return;
 213         }
 214
 215         list_for_each_entry_safe(child_orph, tmp_o, &orph->child_list, child_list) {
 216                 list_del(&child_orph->child_list);
 217                 orphan_delete(c, child_orph);
 218         }
 219
 220         orphan_delete(c, orph);
 221
 222         spin_unlock(&c->orphan_lock);
 223 }
 224
 225 /**
 226  * ubifs_orphan_start_commit - start commit of orphans.
 227  * @c: UBIFS file-system description object
 228  *
 229  * Start commit of orphans.
 230  */
 231 int ubifs_orphan_start_commit(struct ubifs_info *c)
 232 {
 233         struct ubifs_orphan *orphan, **last;
 234
 235         spin_lock(&c->orphan_lock);
 236         last = &c->orph_cnext;
 237         list_for_each_entry(orphan, &c->orph_new, new_list) {
 238                 ubifs_assert(c, orphan->new);
 239                 ubifs_assert(c, !orphan->cmt);
 240                 orphan->new = 0;
 241                 orphan->cmt = 1;
 242                 *last = orphan;
 243                 last = &orphan->cnext;
 244         }
 245         *last = NULL;
 246         c->cmt_orphans = c->new_orphans;
 247         c->new_orphans = 0;
 248         dbg_cmt("%d orphans to commit", c->cmt_orphans);
 249         INIT_LIST_HEAD(&c->orph_new);
 250         if (c->tot_orphans == 0)
 251                 c->no_orphs = 1;
 252         else
 253                 c->no_orphs = 0;
 254         spin_unlock(&c->orphan_lock);
 255         return 0;
 256 }
 257
 258 /**
 259  * avail_orphs - calculate available space.
 260  * @c: UBIFS file-system description object
 261  *
 262  * This function returns the number of orphans that can be written in the
 263  * available space.
 264  */
 265 static int avail_orphs(struct ubifs_info *c)
 266 {
 267         int avail_lebs, avail, gap;
 268
 269         avail_lebs = c->orph_lebs - (c->ohead_lnum - c->orph_first) - 1;
 270         avail = avail_lebs *
 271                ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
 272         gap = c->leb_size - c->ohead_offs;
 273         if (gap >= UBIFS_ORPH_NODE_SZ + sizeof(__le64))
 274                 avail += (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
 275         return avail;
 276 }
 277
 278 /**
 279  * tot_avail_orphs - calculate total space.
 280  * @c: UBIFS file-system description object
 281  *
 282  * This function returns the number of orphans that can be written in half
 283  * the total space. That leaves half the space for adding new orphans.
 284  */
 285 static int tot_avail_orphs(struct ubifs_info *c)
 286 {
 287         int avail_lebs, avail;
 288
 289         avail_lebs = c->orph_lebs;
 290         avail = avail_lebs *
 291                ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
 292         return avail / 2;
 293 }
 294
 295 /**
 296  * do_write_orph_node - write a node to the orphan head.
 297  * @c: UBIFS file-system description object
 298  * @len: length of node
 299  * @atomic: write atomically
 300  *
 301  * This function writes a node to the orphan head from the orphan buffer. If
 302  * %atomic is not zero, then the write is done atomically. On success, %0 is
 303  * returned, otherwise a negative error code is returned.
 304  */
 305 static int do_write_orph_node(struct ubifs_info *c, int len, int atomic)
 306 {
 307         int err = 0;
 308
 309         if (atomic) {
 310                 ubifs_assert(c, c->ohead_offs == 0);
 311                 ubifs_prepare_node(c, c->orph_buf, len, 1);
 312                 len = ALIGN(len, c->min_io_size);
 313                 err = ubifs_leb_change(c, c->ohead_lnum, c->orph_buf, len);
 314         } else {
 315                 if (c->ohead_offs == 0) {
 316                         /* Ensure LEB has been unmapped */
 317                         err = ubifs_leb_unmap(c, c->ohead_lnum);
 318                         if (err)
 319                                 return err;
 320                 }
 321                 err = ubifs_write_node(c, c->orph_buf, len, c->ohead_lnum,
 322                                        c->ohead_offs);
 323         }
 324         return err;
 325 }
 326
 327 /**
 328  * write_orph_node - write an orphan node.
 329  * @c: UBIFS file-system description object
 330  * @atomic: write atomically
 331  *
 332  * This function builds an orphan node from the cnext list and writes it to the
 333  * orphan head. On success, %0 is returned, otherwise a negative error code
 334  * is returned.
 335  */
 336 static int write_orph_node(struct ubifs_info *c, int atomic)
 337 {
 338         struct ubifs_orphan *orphan, *cnext;
 339         struct ubifs_orph_node *orph;
 340         int gap, err, len, cnt, i;
 341
 342         ubifs_assert(c, c->cmt_orphans > 0);
 343         gap = c->leb_size - c->ohead_offs;
 344         if (gap < UBIFS_ORPH_NODE_SZ + sizeof(__le64)) {
 345                 c->ohead_lnum += 1;
 346                 c->ohead_offs = 0;
 347                 gap = c->leb_size;
 348                 if (c->ohead_lnum > c->orph_last) {
 349                         /*
 350                          * We limit the number of orphans so that this should
 351                          * never happen.
 352                          */
 353                         ubifs_err(c, "out of space in orphan area");
 354                         return -EINVAL;
 355                 }
 356         }
 357         cnt = (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
 358         if (cnt > c->cmt_orphans)
 359                 cnt = c->cmt_orphans;
 360         len = UBIFS_ORPH_NODE_SZ + cnt * sizeof(__le64);
 361         ubifs_assert(c, c->orph_buf);
 362         orph = c->orph_buf;
 363         orph->ch.node_type = UBIFS_ORPH_NODE;
 364         spin_lock(&c->orphan_lock);
 365         cnext = c->orph_cnext;
 366         for (i = 0; i < cnt; i++) {
 367                 orphan = cnext;
 368                 ubifs_assert(c, orphan->cmt);
 369                 orph->inos[i] = cpu_to_le64(orphan->inum);
 370                 orphan->cmt = 0;
 371                 cnext = orphan->cnext;
 372                 orphan->cnext = NULL;
 373         }
 374         c->orph_cnext = cnext;
 375         c->cmt_orphans -= cnt;
 376         spin_unlock(&c->orphan_lock);
 377         if (c->cmt_orphans)
 378                 orph->cmt_no = cpu_to_le64(c->cmt_no);
 379         else
 380                 /* Mark the last node of the commit */
 381                 orph->cmt_no = cpu_to_le64((c->cmt_no) | (1ULL << 63));
 382         ubifs_assert(c, c->ohead_offs + len <= c->leb_size);
 383         ubifs_assert(c, c->ohead_lnum >= c->orph_first);
 384         ubifs_assert(c, c->ohead_lnum <= c->orph_last);
 385         err = do_write_orph_node(c, len, atomic);
 386         c->ohead_offs += ALIGN(len, c->min_io_size);
 387         c->ohead_offs = ALIGN(c->ohead_offs, 8);
 388         return err;
 389 }
 390
 391 /**
 392  * write_orph_nodes - write orphan nodes until there are no more to commit.
 393  * @c: UBIFS file-system description object
 394  * @atomic: write atomically
 395  *
 396  * This function writes orphan nodes for all the orphans to commit. On success,
 397  * %0 is returned, otherwise a negative error code is returned.
 398  */
 399 static int write_orph_nodes(struct ubifs_info *c, int atomic)
 400 {
 401         int err;
 402
 403         while (c->cmt_orphans > 0) {
 404                 err = write_orph_node(c, atomic);
 405                 if (err)
 406                         return err;
 407         }
 408         if (atomic) {
 409                 int lnum;
 410
 411                 /* Unmap any unused LEBs after consolidation */
 412                 for (lnum = c->ohead_lnum + 1; lnum <= c->orph_last; lnum++) {
 413                         err = ubifs_leb_unmap(c, lnum);
 414                         if (err)
 415                                 return err;
 416                 }
 417         }
 418         return 0;
 419 }
 420
 421 /**
 422  * consolidate - consolidate the orphan area.
 423  * @c: UBIFS file-system description object
 424  *
 425  * This function enables consolidation by putting all the orphans into the list
 426  * to commit. The list is in the order that the orphans were added, and the
 427  * LEBs are written atomically in order, so at no time can orphans be lost by
 428  * an unclean unmount.
 429  *
 430  * This function returns %0 on success and a negative error code on failure.
 431  */
 432 static int consolidate(struct ubifs_info *c)
 433 {
 434         int tot_avail = tot_avail_orphs(c), err = 0;
 435
 436         spin_lock(&c->orphan_lock);
 437         dbg_cmt("there is space for %d orphans and there are %d",
 438                 tot_avail, c->tot_orphans);
 439         if (c->tot_orphans - c->new_orphans <= tot_avail) {
 440                 struct ubifs_orphan *orphan, **last;
 441                 int cnt = 0;
 442
 443                 /* Change the cnext list to include all non-new orphans */
 444                 last = &c->orph_cnext;
 445                 list_for_each_entry(orphan, &c->orph_list, list) {
 446                         if (orphan->new)
 447                                 continue;
 448                         orphan->cmt = 1;
 449                         *last = orphan;
 450                         last = &orphan->cnext;
 451                         cnt += 1;
 452                 }
 453                 *last = NULL;
 454                 ubifs_assert(c, cnt == c->tot_orphans - c->new_orphans);
 455                 c->cmt_orphans = cnt;
 456                 c->ohead_lnum = c->orph_first;
 457                 c->ohead_offs = 0;
 458         } else {
 459                 /*
 460                  * We limit the number of orphans so that this should
 461                  * never happen.
 462                  */
 463                 ubifs_err(c, "out of space in orphan area");
 464                 err = -EINVAL;
 465         }
 466         spin_unlock(&c->orphan_lock);
 467         return err;
 468 }
 469
 470 /**
 471  * commit_orphans - commit orphans.
 472  * @c: UBIFS file-system description object
 473  *
 474  * This function commits orphans to flash. On success, %0 is returned,
 475  * otherwise a negative error code is returned.
 476  */
 477 static int commit_orphans(struct ubifs_info *c)
 478 {
 479         int avail, atomic = 0, err;
 480
 481         ubifs_assert(c, c->cmt_orphans > 0);
 482         avail = avail_orphs(c);
 483         if (avail < c->cmt_orphans) {
 484                 /* Not enough space to write new orphans, so consolidate */
 485                 err = consolidate(c);
 486                 if (err)
 487                         return err;
 488                 atomic = 1;
 489         }
 490         err = write_orph_nodes(c, atomic);
 491         return err;
 492 }
 493
 494 /**
 495  * erase_deleted - erase the orphans marked for deletion.
 496  * @c: UBIFS file-system description object
 497  *
 498  * During commit, the orphans being committed cannot be deleted, so they are
 499  * marked for deletion and deleted by this function. Also, the recovery
 500  * adds killed orphans to the deletion list, and therefore they are deleted
 501  * here too.
 502  */
 503 static void erase_deleted(struct ubifs_info *c)
 504 {
 505         struct ubifs_orphan *orphan, *dnext;
 506
 507         spin_lock(&c->orphan_lock);
 508         dnext = c->orph_dnext;
 509         while (dnext) {
 510                 orphan = dnext;
 511                 dnext = orphan->dnext;
 512                 ubifs_assert(c, !orphan->new);
 513                 ubifs_assert(c, orphan->del);
 514                 rb_erase(&orphan->rb, &c->orph_tree);
 515                 list_del(&orphan->list);
 516                 c->tot_orphans -= 1;
 517                 dbg_gen("deleting orphan ino %lu", (unsigned long)orphan->inum);
 518                 kfree(orphan);
 519         }
 520         c->orph_dnext = NULL;
 521         spin_unlock(&c->orphan_lock);
 522 }
 523
 524 /**
 525  * ubifs_orphan_end_commit - end commit of orphans.
 526  * @c: UBIFS file-system description object
 527  *
 528  * End commit of orphans.
 529  */
 530 int ubifs_orphan_end_commit(struct ubifs_info *c)
 531 {
 532         int err;
 533
 534         if (c->cmt_orphans != 0) {
 535                 err = commit_orphans(c);
 536                 if (err)
 537                         return err;
 538         }
 539         erase_deleted(c);
 540         err = dbg_check_orphans(c);
 541         return err;
 542 }
 543
 544 /**
 545  * ubifs_clear_orphans - erase all LEBs used for orphans.
 546  * @c: UBIFS file-system description object
 547  *
 548  * If recovery is not required, then the orphans from the previous session
 549  * are not needed. This function locates the LEBs used to record
 550  * orphans, and un-maps them.
 551  */
 552 int ubifs_clear_orphans(struct ubifs_info *c)
 553 {
 554         int lnum, err;
 555
 556         for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
 557                 err = ubifs_leb_unmap(c, lnum);
 558                 if (err)
 559                         return err;
 560         }
 561         c->ohead_lnum = c->orph_first;
 562         c->ohead_offs = 0;
 563         return 0;
 564 }
 565
 566 /**
 567  * insert_dead_orphan - insert an orphan.
 568  * @c: UBIFS file-system description object
 569  * @inum: orphan inode number
 570  *
 571  * This function is a helper to the 'do_kill_orphans()' function. The orphan
 572  * must be kept until the next commit, so it is added to the rb-tree and the
 573  * deletion list.
 574  */
 575 static int insert_dead_orphan(struct ubifs_info *c, ino_t inum)
 576 {
 577         struct ubifs_orphan *orphan, *o;
 578         struct rb_node **p, *parent = NULL;
 579
 580         orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_KERNEL);
 581         if (!orphan)
 582                 return -ENOMEM;
 583         orphan->inum = inum;
 584
 585         p = &c->orph_tree.rb_node;
 586         while (*p) {
 587                 parent = *p;
 588                 o = rb_entry(parent, struct ubifs_orphan, rb);
 589                 if (inum < o->inum)
 590                         p = &(*p)->rb_left;
 591                 else if (inum > o->inum)
 592                         p = &(*p)->rb_right;
 593                 else {
 594                         /* Already added - no problem */
 595                         kfree(orphan);
 596                         return 0;
 597                 }
 598         }
 599         c->tot_orphans += 1;
 600         rb_link_node(&orphan->rb, parent, p);
 601         rb_insert_color(&orphan->rb, &c->orph_tree);
 602         list_add_tail(&orphan->list, &c->orph_list);
 603         orphan->del = 1;
 604         orphan->dnext = c->orph_dnext;
 605         c->orph_dnext = orphan;
 606         dbg_mnt("ino %lu, new %d, tot %d", (unsigned long)inum,
 607                 c->new_orphans, c->tot_orphans);
 608         return 0;
 609 }
 610
 611 /**
 612  * do_kill_orphans - remove orphan inodes from the index.
 613  * @c: UBIFS file-system description object
 614  * @sleb: scanned LEB
 615  * @last_cmt_no: cmt_no of last orphan node read is passed and returned here
 616  * @outofdate: whether the LEB is out of date is returned here
 617  * @last_flagged: whether the end orphan node is encountered
 618  *
 619  * This function is a helper to the 'kill_orphans()' function. It goes through
 620  * every orphan node in a LEB and for every inode number recorded, removes
 621  * all keys for that inode from the TNC.
 622  */
 623 static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
 624                            unsigned long long *last_cmt_no, int *outofdate,
 625                            int *last_flagged)
 626 {
 627         struct ubifs_scan_node *snod;
 628         struct ubifs_orph_node *orph;
 629         struct ubifs_ino_node *ino = NULL;
 630         unsigned long long cmt_no;
 631         ino_t inum;
 632         int i, n, err, first = 1;
 633
 634         ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
 635         if (!ino)
 636                 return -ENOMEM;
 637
 638         list_for_each_entry(snod, &sleb->nodes, list) {
 639                 if (snod->type != UBIFS_ORPH_NODE) {
 640                         ubifs_err(c, "invalid node type %d in orphan area at %d:%d",
 641                                   snod->type, sleb->lnum, snod->offs);
 642                         ubifs_dump_node(c, snod->node);
 643                         err = -EINVAL;
 644                         goto out_free;
 645                 }
 646
 647                 orph = snod->node;
 648
 649                 /* Check commit number */
 650                 cmt_no = le64_to_cpu(orph->cmt_no) & LLONG_MAX;
 651                 /*
 652                  * The commit number on the master node may be less, because
 653                  * of a failed commit. If there are several failed commits in a
 654                  * row, the commit number written on orphan nodes will continue
 655                  * to increase (because the commit number is adjusted here) even
 656                  * though the commit number on the master node stays the same
 657                  * because the master node has not been re-written.
 658                  */
 659                 if (cmt_no > c->cmt_no)
 660                         c->cmt_no = cmt_no;
 661                 if (cmt_no < *last_cmt_no && *last_flagged) {
 662                         /*
 663                          * The last orphan node had a higher commit number and
 664                          * was flagged as the last written for that commit
 665                          * number. That makes this orphan node, out of date.
 666                          */
 667                         if (!first) {
 668                                 ubifs_err(c, "out of order commit number %llu in orphan node at %d:%d",
 669                                           cmt_no, sleb->lnum, snod->offs);
 670                                 ubifs_dump_node(c, snod->node);
 671                                 err = -EINVAL;
 672                                 goto out_free;
 673                         }
 674                         dbg_rcvry("out of date LEB %d", sleb->lnum);
 675                         *outofdate = 1;
 676                         err = 0;
 677                         goto out_free;
 678                 }
 679
 680                 if (first)
 681                         first = 0;
 682
 683                 n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
 684                 for (i = 0; i < n; i++) {
 685                         union ubifs_key key1, key2;
 686
 687                         inum = le64_to_cpu(orph->inos[i]);
 688
 689                         ino_key_init(c, &key1, inum);
 690                         err = ubifs_tnc_lookup(c, &key1, ino);
 691                         if (err && err != -ENOENT)
 692                                 goto out_free;
 693
 694                         /*
 695                          * Check whether an inode can really get deleted.
 696                          * linkat() with O_TMPFILE allows rebirth of an inode.
 697                          */
 698                         if (err == 0 && ino->nlink == 0) {
 699                                 dbg_rcvry("deleting orphaned inode %lu",
 700                                           (unsigned long)inum);
 701
 702                                 lowest_ino_key(c, &key1, inum);
 703                                 highest_ino_key(c, &key2, inum);
 704
 705                                 err = ubifs_tnc_remove_range(c, &key1, &key2);
 706                                 if (err)
 707                                         goto out_ro;
 708                         }
 709
 710                         err = insert_dead_orphan(c, inum);
 711                         if (err)
 712                                 goto out_free;
 713                 }
 714
 715                 *last_cmt_no = cmt_no;
 716                 if (le64_to_cpu(orph->cmt_no) & (1ULL << 63)) {
 717                         dbg_rcvry("last orph node for commit %llu at %d:%d",
 718                                   cmt_no, sleb->lnum, snod->offs);
 719                         *last_flagged = 1;
 720                 } else
 721                         *last_flagged = 0;
 722         }
 723
 724         err = 0;
 725 out_free:
 726         kfree(ino);
 727         return err;
 728
 729 out_ro:
 730         ubifs_ro_mode(c, err);
 731         kfree(ino);
 732         return err;
 733 }
 734
 735 /**
 736  * kill_orphans - remove all orphan inodes from the index.
 737  * @c: UBIFS file-system description object
 738  *
 739  * If recovery is required, then orphan inodes recorded during the previous
 740  * session (which ended with an unclean unmount) must be deleted from the index.
 741  * This is done by updating the TNC, but since the index is not updated until
 742  * the next commit, the LEBs where the orphan information is recorded are not
 743  * erased until the next commit.
 744  */
 745 static int kill_orphans(struct ubifs_info *c)
 746 {
 747         unsigned long long last_cmt_no = 0;
 748         int lnum, err = 0, outofdate = 0, last_flagged = 0;
 749
 750         c->ohead_lnum = c->orph_first;
 751         c->ohead_offs = 0;
 752         /* Check no-orphans flag and skip this if no orphans */
 753         if (c->no_orphs) {
 754                 dbg_rcvry("no orphans");
 755                 return 0;
 756         }
 757         /*
 758          * Orph nodes always start at c->orph_first and are written to each
 759          * successive LEB in turn. Generally unused LEBs will have been unmapped
 760          * but may contain out of date orphan nodes if the unmap didn't go
 761          * through. In addition, the last orphan node written for each commit is
 762          * marked (top bit of orph->cmt_no is set to 1). It is possible that
 763          * there are orphan nodes from the next commit (i.e. the commit did not
 764          * complete successfully). In that case, no orphans will have been lost
 765          * due to the way that orphans are written, and any orphans added will
 766          * be valid orphans anyway and so can be deleted.
 767          */
 768         for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
 769                 struct ubifs_scan_leb *sleb;
 770
 771                 dbg_rcvry("LEB %d", lnum);
 772                 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
 773                 if (IS_ERR(sleb)) {
 774                         if (PTR_ERR(sleb) == -EUCLEAN)
 775                                 sleb = ubifs_recover_leb(c, lnum, 0,
 776                                                          c->sbuf, -1);
 777                         if (IS_ERR(sleb)) {
 778                                 err = PTR_ERR(sleb);
 779                                 break;
 780                         }
 781                 }
 782                 err = do_kill_orphans(c, sleb, &last_cmt_no, &outofdate,
 783                                       &last_flagged);
 784                 if (err || outofdate) {
 785                         ubifs_scan_destroy(sleb);
 786                         break;
 787                 }
 788                 if (sleb->endpt) {
 789                         c->ohead_lnum = lnum;
 790                         c->ohead_offs = sleb->endpt;
 791                 }
 792                 ubifs_scan_destroy(sleb);
 793         }
 794         return err;
 795 }
 796
 797 /**
 798  * ubifs_mount_orphans - delete orphan inodes and erase LEBs that recorded them.
 799  * @c: UBIFS file-system description object
 800  * @unclean: indicates recovery from unclean unmount
 801  * @read_only: indicates read only mount
 802  *
 803  * This function is called when mounting to erase orphans from the previous
 804  * session. If UBIFS was not unmounted cleanly, then the inodes recorded as
 805  * orphans are deleted.
 806  */
 807 int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
 808 {
 809         int err = 0;
 810
 811         c->max_orphans = tot_avail_orphs(c);
 812
 813         if (!read_only) {
 814                 c->orph_buf = vmalloc(c->leb_size);
 815                 if (!c->orph_buf)
 816                         return -ENOMEM;
 817         }
 818
 819         if (unclean)
 820                 err = kill_orphans(c);
 821         else if (!read_only)
 822                 err = ubifs_clear_orphans(c);
 823
 824         return err;
 825 }
 826
 827 /*
 828  * Everything below is related to debugging.
 829  */
 830
 831 struct check_orphan {
 832         struct rb_node rb;
 833         ino_t inum;
 834 };
 835
 836 struct check_info {
 837         unsigned long last_ino;
 838         unsigned long tot_inos;
 839         unsigned long missing;
 840         unsigned long long leaf_cnt;
 841         struct ubifs_ino_node *node;
 842         struct rb_root root;
 843 };
 844
 845 static bool dbg_find_orphan(struct ubifs_info *c, ino_t inum)
 846 {
 847         bool found = false;
 848
 849         spin_lock(&c->orphan_lock);
 850         found = !!lookup_orphan(c, inum);
 851         spin_unlock(&c->orphan_lock);
 852
 853         return found;
 854 }
 855
 856 static int dbg_ins_check_orphan(struct rb_root *root, ino_t inum)
 857 {
 858         struct check_orphan *orphan, *o;
 859         struct rb_node **p, *parent = NULL;
 860
 861         orphan = kzalloc(sizeof(struct check_orphan), GFP_NOFS);
 862         if (!orphan)
 863                 return -ENOMEM;
 864         orphan->inum = inum;
 865
 866         p = &root->rb_node;
 867         while (*p) {
 868                 parent = *p;
 869                 o = rb_entry(parent, struct check_orphan, rb);
 870                 if (inum < o->inum)
 871                         p = &(*p)->rb_left;
 872                 else if (inum > o->inum)
 873                         p = &(*p)->rb_right;
 874                 else {
 875                         kfree(orphan);
 876                         return 0;
 877                 }
 878         }
 879         rb_link_node(&orphan->rb, parent, p);
 880         rb_insert_color(&orphan->rb, root);
 881         return 0;
 882 }
 883
 884 static int dbg_find_check_orphan(struct rb_root *root, ino_t inum)
 885 {
 886         struct check_orphan *o;
 887         struct rb_node *p;
 888
 889         p = root->rb_node;
 890         while (p) {
 891                 o = rb_entry(p, struct check_orphan, rb);
 892                 if (inum < o->inum)
 893                         p = p->rb_left;
 894                 else if (inum > o->inum)
 895                         p = p->rb_right;
 896                 else
 897                         return 1;
 898         }
 899         return 0;
 900 }
 901
 902 static void dbg_free_check_tree(struct rb_root *root)
 903 {
 904         struct check_orphan *o, *n;
 905
 906         rbtree_postorder_for_each_entry_safe(o, n, root, rb)
 907                 kfree(o);
 908 }
 909
 910 static int dbg_orphan_check(struct ubifs_info *c, struct ubifs_zbranch *zbr,
 911                             void *priv)
 912 {
 913         struct check_info *ci = priv;
 914         ino_t inum;
 915         int err;
 916
 917         inum = key_inum(c, &zbr->key);
 918         if (inum != ci->last_ino) {
 919                 /* Lowest node type is the inode node, so it comes first */
 920                 if (key_type(c, &zbr->key) != UBIFS_INO_KEY)
 921                         ubifs_err(c, "found orphan node ino %lu, type %d",
 922                                   (unsigned long)inum, key_type(c, &zbr->key));
 923                 ci->last_ino = inum;
 924                 ci->tot_inos += 1;
 925                 err = ubifs_tnc_read_node(c, zbr, ci->node);
 926                 if (err) {
 927                         ubifs_err(c, "node read failed, error %d", err);
 928                         return err;
 929                 }
 930                 if (ci->node->nlink == 0)
 931                         /* Must be recorded as an orphan */
 932                         if (!dbg_find_check_orphan(&ci->root, inum) &&
 933                             !dbg_find_orphan(c, inum)) {
 934                                 ubifs_err(c, "missing orphan, ino %lu",
 935                                           (unsigned long)inum);
 936                                 ci->missing += 1;
 937                         }
 938         }
 939         ci->leaf_cnt += 1;
 940         return 0;
 941 }
 942
 943 static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
 944 {
 945         struct ubifs_scan_node *snod;
 946         struct ubifs_orph_node *orph;
 947         ino_t inum;
 948         int i, n, err;
 949
 950         list_for_each_entry(snod, &sleb->nodes, list) {
 951                 cond_resched();
 952                 if (snod->type != UBIFS_ORPH_NODE)
 953                         continue;
 954                 orph = snod->node;
 955                 n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
 956                 for (i = 0; i < n; i++) {
 957                         inum = le64_to_cpu(orph->inos[i]);
 958                         err = dbg_ins_check_orphan(&ci->root, inum);
 959                         if (err)
 960                                 return err;
 961                 }
 962         }
 963         return 0;
 964 }
 965
 966 static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
 967 {
 968         int lnum, err = 0;
 969         void *buf;
 970
 971         /* Check no-orphans flag and skip this if no orphans */
 972         if (c->no_orphs)
 973                 return 0;
 974
 975         buf = __vmalloc(c->leb_size, GFP_NOFS, PAGE_KERNEL);
 976         if (!buf) {
 977                 ubifs_err(c, "cannot allocate memory to check orphans");
 978                 return 0;
 979         }
 980
 981         for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
 982                 struct ubifs_scan_leb *sleb;
 983
 984                 sleb = ubifs_scan(c, lnum, 0, buf, 0);
 985                 if (IS_ERR(sleb)) {
 986                         err = PTR_ERR(sleb);
 987                         break;
 988                 }
 989
 990                 err = dbg_read_orphans(ci, sleb);
 991                 ubifs_scan_destroy(sleb);
 992                 if (err)
 993                         break;
 994         }
 995
 996         vfree(buf);
 997         return err;
 998 }
 999
1000 static int dbg_check_orphans(struct ubifs_info *c)
1001 {
1002         struct check_info ci;
1003         int err;
1004
1005         if (!dbg_is_chk_orph(c))
1006                 return 0;
1007
1008         ci.last_ino = 0;
1009         ci.tot_inos = 0;
1010         ci.missing  = 0;
1011         ci.leaf_cnt = 0;
1012         ci.root = RB_ROOT;
1013         ci.node = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
1014         if (!ci.node) {
1015                 ubifs_err(c, "out of memory");
1016                 return -ENOMEM;
1017         }
1018
1019         err = dbg_scan_orphans(c, &ci);
1020         if (err)
1021                 goto out;
1022
1023         err = dbg_walk_index(c, &dbg_orphan_check, NULL, &ci);
1024         if (err) {
1025                 ubifs_err(c, "cannot scan TNC, error %d", err);
1026                 goto out;
1027         }
1028
1029         if (ci.missing) {
1030                 ubifs_err(c, "%lu missing orphan(s)", ci.missing);
1031                 err = -EINVAL;
1032                 goto out;
1033         }
1034
1035         dbg_cmt("last inode number is %lu", ci.last_ino);
1036         dbg_cmt("total number of inodes is %lu", ci.tot_inos);
1037         dbg_cmt("total number of leaf nodes is %llu", ci.leaf_cnt);
1038
1039 out:
1040         dbg_free_check_tree(&ci.root);
1041         kfree(ci.node);
1042         return err;
1043 }