fs/ubifs/orphan.c

   1 /*
   2  * This file is part of UBIFS.
   3  *
   4  * Copyright (C) 2006-2008 Nokia Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  *
  19  * Author: Adrian Hunter
  20  */
  21
  22 #include "ubifs.h"
  23
  24 /*
  25  * An orphan is an inode number whose inode node has been committed to the index
  26  * with a link count of zero. That happens when an open file is deleted
  27  * (unlinked) and then a commit is run. In the normal course of events the inode
  28  * would be deleted when the file is closed. However in the case of an unclean
  29  * unmount, orphans need to be accounted for. After an unclean unmount, the
  30  * orphans' inodes must be deleted which means either scanning the entire index
  31  * looking for them, or keeping a list on flash somewhere. This unit implements
  32  * the latter approach.
  33  *
  34  * The orphan area is a fixed number of LEBs situated between the LPT area and
  35  * the main area. The number of orphan area LEBs is specified when the file
  36  * system is created. The minimum number is 1. The size of the orphan area
  37  * should be so that it can hold the maximum number of orphans that are expected
  38  * to ever exist at one time.
  39  *
  40  * The number of orphans that can fit in a LEB is:
  41  *
  42  *         (c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64)
  43  *
  44  * For example: a 15872 byte LEB can fit 1980 orphans so 1 LEB may be enough.
  45  *
  46  * Orphans are accumulated in a rb-tree. When an inode's link count drops to
  47  * zero, the inode number is added to the rb-tree. It is removed from the tree
  48  * when the inode is deleted.  Any new orphans that are in the orphan tree when
  49  * the commit is run, are written to the orphan area in 1 or more orphan nodes.
  50  * If the orphan area is full, it is consolidated to make space.  There is
  51  * always enough space because validation prevents the user from creating more
  52  * than the maximum number of orphans allowed.
  53  */
  54
  55 static int dbg_check_orphans(struct ubifs_info *c);
  56
  57 /**
  58  * ubifs_add_orphan - add an orphan.
  59  * @c: UBIFS file-system description object
  60  * @inum: orphan inode number
  61  *
  62  * Add an orphan. This function is called when an inodes link count drops to
  63  * zero.
  64  */
  65 int ubifs_add_orphan(struct ubifs_info *c, ino_t inum)
  66 {
  67         struct ubifs_orphan *orphan, *o;
  68         struct rb_node **p, *parent = NULL;
  69
  70         orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_NOFS);
  71         if (!orphan)
  72                 return -ENOMEM;
  73         orphan->inum = inum;
  74         orphan->new = 1;
  75
  76         spin_lock(&c->orphan_lock);
  77         if (c->tot_orphans >= c->max_orphans) {
  78                 spin_unlock(&c->orphan_lock);
  79                 kfree(orphan);
  80                 return -ENFILE;
  81         }
  82         p = &c->orph_tree.rb_node;
  83         while (*p) {
  84                 parent = *p;
  85                 o = rb_entry(parent, struct ubifs_orphan, rb);
  86                 if (inum < o->inum)
  87                         p = &(*p)->rb_left;
  88                 else if (inum > o->inum)
  89                         p = &(*p)->rb_right;
  90                 else {
  91                         ubifs_err("orphaned twice");
  92                         spin_unlock(&c->orphan_lock);
  93                         kfree(orphan);
  94                         return 0;
  95                 }
  96         }
  97         c->tot_orphans += 1;
  98         c->new_orphans += 1;
  99         rb_link_node(&orphan->rb, parent, p);
 100         rb_insert_color(&orphan->rb, &c->orph_tree);
 101         list_add_tail(&orphan->list, &c->orph_list);
 102         list_add_tail(&orphan->new_list, &c->orph_new);
 103         spin_unlock(&c->orphan_lock);
 104         dbg_gen("ino %lu", (unsigned long)inum);
 105         return 0;
 106 }
 107
 108 /**
 109  * ubifs_delete_orphan - delete an orphan.
 110  * @c: UBIFS file-system description object
 111  * @inum: orphan inode number
 112  *
 113  * Delete an orphan. This function is called when an inode is deleted.
 114  */
 115 void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
 116 {
 117         struct ubifs_orphan *o;
 118         struct rb_node *p;
 119
 120         spin_lock(&c->orphan_lock);
 121         p = c->orph_tree.rb_node;
 122         while (p) {
 123                 o = rb_entry(p, struct ubifs_orphan, rb);
 124                 if (inum < o->inum)
 125                         p = p->rb_left;
 126                 else if (inum > o->inum)
 127                         p = p->rb_right;
 128                 else {
 129                         if (o->dnext) {
 130                                 spin_unlock(&c->orphan_lock);
 131                                 dbg_gen("deleted twice ino %lu",
 132                                         (unsigned long)inum);
 133                                 return;
 134                         }
 135                         if (o->cnext) {
 136                                 o->dnext = c->orph_dnext;
 137                                 c->orph_dnext = o;
 138                                 spin_unlock(&c->orphan_lock);
 139                                 dbg_gen("delete later ino %lu",
 140                                         (unsigned long)inum);
 141                                 return;
 142                         }
 143                         rb_erase(p, &c->orph_tree);
 144                         list_del(&o->list);
 145                         c->tot_orphans -= 1;
 146                         if (o->new) {
 147                                 list_del(&o->new_list);
 148                                 c->new_orphans -= 1;
 149                         }
 150                         spin_unlock(&c->orphan_lock);
 151                         kfree(o);
 152                         dbg_gen("inum %lu", (unsigned long)inum);
 153                         return;
 154                 }
 155         }
 156         spin_unlock(&c->orphan_lock);
 157         ubifs_err("missing orphan ino %lu", (unsigned long)inum);
 158         dump_stack();
 159 }
 160
 161 /**
 162  * ubifs_orphan_start_commit - start commit of orphans.
 163  * @c: UBIFS file-system description object
 164  *
 165  * Start commit of orphans.
 166  */
 167 int ubifs_orphan_start_commit(struct ubifs_info *c)
 168 {
 169         struct ubifs_orphan *orphan, **last;
 170
 171         spin_lock(&c->orphan_lock);
 172         last = &c->orph_cnext;
 173         list_for_each_entry(orphan, &c->orph_new, new_list) {
 174                 ubifs_assert(orphan->new);
 175                 orphan->new = 0;
 176                 *last = orphan;
 177                 last = &orphan->cnext;
 178         }
 179         *last = NULL;
 180         c->cmt_orphans = c->new_orphans;
 181         c->new_orphans = 0;
 182         dbg_cmt("%d orphans to commit", c->cmt_orphans);
 183         INIT_LIST_HEAD(&c->orph_new);
 184         if (c->tot_orphans == 0)
 185                 c->no_orphs = 1;
 186         else
 187                 c->no_orphs = 0;
 188         spin_unlock(&c->orphan_lock);
 189         return 0;
 190 }
 191
 192 /**
 193  * avail_orphs - calculate available space.
 194  * @c: UBIFS file-system description object
 195  *
 196  * This function returns the number of orphans that can be written in the
 197  * available space.
 198  */
 199 static int avail_orphs(struct ubifs_info *c)
 200 {
 201         int avail_lebs, avail, gap;
 202
 203         avail_lebs = c->orph_lebs - (c->ohead_lnum - c->orph_first) - 1;
 204         avail = avail_lebs *
 205                ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
 206         gap = c->leb_size - c->ohead_offs;
 207         if (gap >= UBIFS_ORPH_NODE_SZ + sizeof(__le64))
 208                 avail += (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
 209         return avail;
 210 }
 211
 212 /**
 213  * tot_avail_orphs - calculate total space.
 214  * @c: UBIFS file-system description object
 215  *
 216  * This function returns the number of orphans that can be written in half
 217  * the total space. That leaves half the space for adding new orphans.
 218  */
 219 static int tot_avail_orphs(struct ubifs_info *c)
 220 {
 221         int avail_lebs, avail;
 222
 223         avail_lebs = c->orph_lebs;
 224         avail = avail_lebs *
 225                ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
 226         return avail / 2;
 227 }
 228
 229 /**
 230  * do_write_orph_node - write a node to the orphan head.
 231  * @c: UBIFS file-system description object
 232  * @len: length of node
 233  * @atomic: write atomically
 234  *
 235  * This function writes a node to the orphan head from the orphan buffer. If
 236  * %atomic is not zero, then the write is done atomically. On success, %0 is
 237  * returned, otherwise a negative error code is returned.
 238  */
 239 static int do_write_orph_node(struct ubifs_info *c, int len, int atomic)
 240 {
 241         int err = 0;
 242
 243         if (atomic) {
 244                 ubifs_assert(c->ohead_offs == 0);
 245                 ubifs_prepare_node(c, c->orph_buf, len, 1);
 246                 len = ALIGN(len, c->min_io_size);
 247                 err = ubifs_leb_change(c, c->ohead_lnum, c->orph_buf, len);
 248         } else {
 249                 if (c->ohead_offs == 0) {
 250                         /* Ensure LEB has been unmapped */
 251                         err = ubifs_leb_unmap(c, c->ohead_lnum);
 252                         if (err)
 253                                 return err;
 254                 }
 255                 err = ubifs_write_node(c, c->orph_buf, len, c->ohead_lnum,
 256                                        c->ohead_offs);
 257         }
 258         return err;
 259 }
 260
 261 /**
 262  * write_orph_node - write an orphan node.
 263  * @c: UBIFS file-system description object
 264  * @atomic: write atomically
 265  *
 266  * This function builds an orphan node from the cnext list and writes it to the
 267  * orphan head. On success, %0 is returned, otherwise a negative error code
 268  * is returned.
 269  */
 270 static int write_orph_node(struct ubifs_info *c, int atomic)
 271 {
 272         struct ubifs_orphan *orphan, *cnext;
 273         struct ubifs_orph_node *orph;
 274         int gap, err, len, cnt, i;
 275
 276         ubifs_assert(c->cmt_orphans > 0);
 277         gap = c->leb_size - c->ohead_offs;
 278         if (gap < UBIFS_ORPH_NODE_SZ + sizeof(__le64)) {
 279                 c->ohead_lnum += 1;
 280                 c->ohead_offs = 0;
 281                 gap = c->leb_size;
 282                 if (c->ohead_lnum > c->orph_last) {
 283                         /*
 284                          * We limit the number of orphans so that this should
 285                          * never happen.
 286                          */
 287                         ubifs_err("out of space in orphan area");
 288                         return -EINVAL;
 289                 }
 290         }
 291         cnt = (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
 292         if (cnt > c->cmt_orphans)
 293                 cnt = c->cmt_orphans;
 294         len = UBIFS_ORPH_NODE_SZ + cnt * sizeof(__le64);
 295         ubifs_assert(c->orph_buf);
 296         orph = c->orph_buf;
 297         orph->ch.node_type = UBIFS_ORPH_NODE;
 298         spin_lock(&c->orphan_lock);
 299         cnext = c->orph_cnext;
 300         for (i = 0; i < cnt; i++) {
 301                 orphan = cnext;
 302                 orph->inos[i] = cpu_to_le64(orphan->inum);
 303                 cnext = orphan->cnext;
 304                 orphan->cnext = NULL;
 305         }
 306         c->orph_cnext = cnext;
 307         c->cmt_orphans -= cnt;
 308         spin_unlock(&c->orphan_lock);
 309         if (c->cmt_orphans)
 310                 orph->cmt_no = cpu_to_le64(c->cmt_no);
 311         else
 312                 /* Mark the last node of the commit */
 313                 orph->cmt_no = cpu_to_le64((c->cmt_no) | (1ULL << 63));
 314         ubifs_assert(c->ohead_offs + len <= c->leb_size);
 315         ubifs_assert(c->ohead_lnum >= c->orph_first);
 316         ubifs_assert(c->ohead_lnum <= c->orph_last);
 317         err = do_write_orph_node(c, len, atomic);
 318         c->ohead_offs += ALIGN(len, c->min_io_size);
 319         c->ohead_offs = ALIGN(c->ohead_offs, 8);
 320         return err;
 321 }
 322
 323 /**
 324  * write_orph_nodes - write orphan nodes until there are no more to commit.
 325  * @c: UBIFS file-system description object
 326  * @atomic: write atomically
 327  *
 328  * This function writes orphan nodes for all the orphans to commit. On success,
 329  * %0 is returned, otherwise a negative error code is returned.
 330  */
 331 static int write_orph_nodes(struct ubifs_info *c, int atomic)
 332 {
 333         int err;
 334
 335         while (c->cmt_orphans > 0) {
 336                 err = write_orph_node(c, atomic);
 337                 if (err)
 338                         return err;
 339         }
 340         if (atomic) {
 341                 int lnum;
 342
 343                 /* Unmap any unused LEBs after consolidation */
 344                 lnum = c->ohead_lnum + 1;
 345                 for (lnum = c->ohead_lnum + 1; lnum <= c->orph_last; lnum++) {
 346                         err = ubifs_leb_unmap(c, lnum);
 347                         if (err)
 348                                 return err;
 349                 }
 350         }
 351         return 0;
 352 }
 353
 354 /**
 355  * consolidate - consolidate the orphan area.
 356  * @c: UBIFS file-system description object
 357  *
 358  * This function enables consolidation by putting all the orphans into the list
 359  * to commit. The list is in the order that the orphans were added, and the
 360  * LEBs are written atomically in order, so at no time can orphans be lost by
 361  * an unclean unmount.
 362  *
 363  * This function returns %0 on success and a negative error code on failure.
 364  */
 365 static int consolidate(struct ubifs_info *c)
 366 {
 367         int tot_avail = tot_avail_orphs(c), err = 0;
 368
 369         spin_lock(&c->orphan_lock);
 370         dbg_cmt("there is space for %d orphans and there are %d",
 371                 tot_avail, c->tot_orphans);
 372         if (c->tot_orphans - c->new_orphans <= tot_avail) {
 373                 struct ubifs_orphan *orphan, **last;
 374                 int cnt = 0;
 375
 376                 /* Change the cnext list to include all non-new orphans */
 377                 last = &c->orph_cnext;
 378                 list_for_each_entry(orphan, &c->orph_list, list) {
 379                         if (orphan->new)
 380                                 continue;
 381                         *last = orphan;
 382                         last = &orphan->cnext;
 383                         cnt += 1;
 384                 }
 385                 *last = NULL;
 386                 ubifs_assert(cnt == c->tot_orphans - c->new_orphans);
 387                 c->cmt_orphans = cnt;
 388                 c->ohead_lnum = c->orph_first;
 389                 c->ohead_offs = 0;
 390         } else {
 391                 /*
 392                  * We limit the number of orphans so that this should
 393                  * never happen.
 394                  */
 395                 ubifs_err("out of space in orphan area");
 396                 err = -EINVAL;
 397         }
 398         spin_unlock(&c->orphan_lock);
 399         return err;
 400 }
 401
 402 /**
 403  * commit_orphans - commit orphans.
 404  * @c: UBIFS file-system description object
 405  *
 406  * This function commits orphans to flash. On success, %0 is returned,
 407  * otherwise a negative error code is returned.
 408  */
 409 static int commit_orphans(struct ubifs_info *c)
 410 {
 411         int avail, atomic = 0, err;
 412
 413         ubifs_assert(c->cmt_orphans > 0);
 414         avail = avail_orphs(c);
 415         if (avail < c->cmt_orphans) {
 416                 /* Not enough space to write new orphans, so consolidate */
 417                 err = consolidate(c);
 418                 if (err)
 419                         return err;
 420                 atomic = 1;
 421         }
 422         err = write_orph_nodes(c, atomic);
 423         return err;
 424 }
 425
 426 /**
 427  * erase_deleted - erase the orphans marked for deletion.
 428  * @c: UBIFS file-system description object
 429  *
 430  * During commit, the orphans being committed cannot be deleted, so they are
 431  * marked for deletion and deleted by this function. Also, the recovery
 432  * adds killed orphans to the deletion list, and therefore they are deleted
 433  * here too.
 434  */
 435 static void erase_deleted(struct ubifs_info *c)
 436 {
 437         struct ubifs_orphan *orphan, *dnext;
 438
 439         spin_lock(&c->orphan_lock);
 440         dnext = c->orph_dnext;
 441         while (dnext) {
 442                 orphan = dnext;
 443                 dnext = orphan->dnext;
 444                 ubifs_assert(!orphan->new);
 445                 rb_erase(&orphan->rb, &c->orph_tree);
 446                 list_del(&orphan->list);
 447                 c->tot_orphans -= 1;
 448                 dbg_gen("deleting orphan ino %lu", (unsigned long)orphan->inum);
 449                 kfree(orphan);
 450         }
 451         c->orph_dnext = NULL;
 452         spin_unlock(&c->orphan_lock);
 453 }
 454
 455 /**
 456  * ubifs_orphan_end_commit - end commit of orphans.
 457  * @c: UBIFS file-system description object
 458  *
 459  * End commit of orphans.
 460  */
 461 int ubifs_orphan_end_commit(struct ubifs_info *c)
 462 {
 463         int err;
 464
 465         if (c->cmt_orphans != 0) {
 466                 err = commit_orphans(c);
 467                 if (err)
 468                         return err;
 469         }
 470         erase_deleted(c);
 471         err = dbg_check_orphans(c);
 472         return err;
 473 }
 474
 475 /**
 476  * ubifs_clear_orphans - erase all LEBs used for orphans.
 477  * @c: UBIFS file-system description object
 478  *
 479  * If recovery is not required, then the orphans from the previous session
 480  * are not needed. This function locates the LEBs used to record
 481  * orphans, and un-maps them.
 482  */
 483 int ubifs_clear_orphans(struct ubifs_info *c)
 484 {
 485         int lnum, err;
 486
 487         for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
 488                 err = ubifs_leb_unmap(c, lnum);
 489                 if (err)
 490                         return err;
 491         }
 492         c->ohead_lnum = c->orph_first;
 493         c->ohead_offs = 0;
 494         return 0;
 495 }
 496
 497 /**
 498  * insert_dead_orphan - insert an orphan.
 499  * @c: UBIFS file-system description object
 500  * @inum: orphan inode number
 501  *
 502  * This function is a helper to the 'do_kill_orphans()' function. The orphan
 503  * must be kept until the next commit, so it is added to the rb-tree and the
 504  * deletion list.
 505  */
 506 static int insert_dead_orphan(struct ubifs_info *c, ino_t inum)
 507 {
 508         struct ubifs_orphan *orphan, *o;
 509         struct rb_node **p, *parent = NULL;
 510
 511         orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_KERNEL);
 512         if (!orphan)
 513                 return -ENOMEM;
 514         orphan->inum = inum;
 515
 516         p = &c->orph_tree.rb_node;
 517         while (*p) {
 518                 parent = *p;
 519                 o = rb_entry(parent, struct ubifs_orphan, rb);
 520                 if (inum < o->inum)
 521                         p = &(*p)->rb_left;
 522                 else if (inum > o->inum)
 523                         p = &(*p)->rb_right;
 524                 else {
 525                         /* Already added - no problem */
 526                         kfree(orphan);
 527                         return 0;
 528                 }
 529         }
 530         c->tot_orphans += 1;
 531         rb_link_node(&orphan->rb, parent, p);
 532         rb_insert_color(&orphan->rb, &c->orph_tree);
 533         list_add_tail(&orphan->list, &c->orph_list);
 534         orphan->dnext = c->orph_dnext;
 535         c->orph_dnext = orphan;
 536         dbg_mnt("ino %lu, new %d, tot %d", (unsigned long)inum,
 537                 c->new_orphans, c->tot_orphans);
 538         return 0;
 539 }
 540
 541 /**
 542  * do_kill_orphans - remove orphan inodes from the index.
 543  * @c: UBIFS file-system description object
 544  * @sleb: scanned LEB
 545  * @last_cmt_no: cmt_no of last orphan node read is passed and returned here
 546  * @outofdate: whether the LEB is out of date is returned here
 547  * @last_flagged: whether the end orphan node is encountered
 548  *
 549  * This function is a helper to the 'kill_orphans()' function. It goes through
 550  * every orphan node in a LEB and for every inode number recorded, removes
 551  * all keys for that inode from the TNC.
 552  */
 553 static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
 554                            unsigned long long *last_cmt_no, int *outofdate,
 555                            int *last_flagged)
 556 {
 557         struct ubifs_scan_node *snod;
 558         struct ubifs_orph_node *orph;
 559         unsigned long long cmt_no;
 560         ino_t inum;
 561         int i, n, err, first = 1;
 562
 563         list_for_each_entry(snod, &sleb->nodes, list) {
 564                 if (snod->type != UBIFS_ORPH_NODE) {
 565                         ubifs_err("invalid node type %d in orphan area at "
 566                                   "%d:%d", snod->type, sleb->lnum, snod->offs);
 567                         ubifs_dump_node(c, snod->node);
 568                         return -EINVAL;
 569                 }
 570
 571                 orph = snod->node;
 572
 573                 /* Check commit number */
 574                 cmt_no = le64_to_cpu(orph->cmt_no) & LLONG_MAX;
 575                 /*
 576                  * The commit number on the master node may be less, because
 577                  * of a failed commit. If there are several failed commits in a
 578                  * row, the commit number written on orphan nodes will continue
 579                  * to increase (because the commit number is adjusted here) even
 580                  * though the commit number on the master node stays the same
 581                  * because the master node has not been re-written.
 582                  */
 583                 if (cmt_no > c->cmt_no)
 584                         c->cmt_no = cmt_no;
 585                 if (cmt_no < *last_cmt_no && *last_flagged) {
 586                         /*
 587                          * The last orphan node had a higher commit number and
 588                          * was flagged as the last written for that commit
 589                          * number. That makes this orphan node, out of date.
 590                          */
 591                         if (!first) {
 592                                 ubifs_err("out of order commit number %llu in "
 593                                           "orphan node at %d:%d",
 594                                           cmt_no, sleb->lnum, snod->offs);
 595                                 ubifs_dump_node(c, snod->node);
 596                                 return -EINVAL;
 597                         }
 598                         dbg_rcvry("out of date LEB %d", sleb->lnum);
 599                         *outofdate = 1;
 600                         return 0;
 601                 }
 602
 603                 if (first)
 604                         first = 0;
 605
 606                 n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
 607                 for (i = 0; i < n; i++) {
 608                         inum = le64_to_cpu(orph->inos[i]);
 609                         dbg_rcvry("deleting orphaned inode %lu",
 610                                   (unsigned long)inum);
 611                         err = ubifs_tnc_remove_ino(c, inum);
 612                         if (err)
 613                                 return err;
 614                         err = insert_dead_orphan(c, inum);
 615                         if (err)
 616                                 return err;
 617                 }
 618
 619                 *last_cmt_no = cmt_no;
 620                 if (le64_to_cpu(orph->cmt_no) & (1ULL << 63)) {
 621                         dbg_rcvry("last orph node for commit %llu at %d:%d",
 622                                   cmt_no, sleb->lnum, snod->offs);
 623                         *last_flagged = 1;
 624                 } else
 625                         *last_flagged = 0;
 626         }
 627
 628         return 0;
 629 }
 630
 631 /**
 632  * kill_orphans - remove all orphan inodes from the index.
 633  * @c: UBIFS file-system description object
 634  *
 635  * If recovery is required, then orphan inodes recorded during the previous
 636  * session (which ended with an unclean unmount) must be deleted from the index.
 637  * This is done by updating the TNC, but since the index is not updated until
 638  * the next commit, the LEBs where the orphan information is recorded are not
 639  * erased until the next commit.
 640  */
 641 static int kill_orphans(struct ubifs_info *c)
 642 {
 643         unsigned long long last_cmt_no = 0;
 644         int lnum, err = 0, outofdate = 0, last_flagged = 0;
 645
 646         c->ohead_lnum = c->orph_first;
 647         c->ohead_offs = 0;
 648         /* Check no-orphans flag and skip this if no orphans */
 649         if (c->no_orphs) {
 650                 dbg_rcvry("no orphans");
 651                 return 0;
 652         }
 653         /*
 654          * Orph nodes always start at c->orph_first and are written to each
 655          * successive LEB in turn. Generally unused LEBs will have been unmapped
 656          * but may contain out of date orphan nodes if the unmap didn't go
 657          * through. In addition, the last orphan node written for each commit is
 658          * marked (top bit of orph->cmt_no is set to 1). It is possible that
 659          * there are orphan nodes from the next commit (i.e. the commit did not
 660          * complete successfully). In that case, no orphans will have been lost
 661          * due to the way that orphans are written, and any orphans added will
 662          * be valid orphans anyway and so can be deleted.
 663          */
 664         for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
 665                 struct ubifs_scan_leb *sleb;
 666
 667                 dbg_rcvry("LEB %d", lnum);
 668                 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
 669                 if (IS_ERR(sleb)) {
 670                         if (PTR_ERR(sleb) == -EUCLEAN)
 671                                 sleb = ubifs_recover_leb(c, lnum, 0,
 672                                                          c->sbuf, -1);
 673                         if (IS_ERR(sleb)) {
 674                                 err = PTR_ERR(sleb);
 675                                 break;
 676                         }
 677                 }
 678                 err = do_kill_orphans(c, sleb, &last_cmt_no, &outofdate,
 679                                       &last_flagged);
 680                 if (err || outofdate) {
 681                         ubifs_scan_destroy(sleb);
 682                         break;
 683                 }
 684                 if (sleb->endpt) {
 685                         c->ohead_lnum = lnum;
 686                         c->ohead_offs = sleb->endpt;
 687                 }
 688                 ubifs_scan_destroy(sleb);
 689         }
 690         return err;
 691 }
 692
 693 /**
 694  * ubifs_mount_orphans - delete orphan inodes and erase LEBs that recorded them.
 695  * @c: UBIFS file-system description object
 696  * @unclean: indicates recovery from unclean unmount
 697  * @read_only: indicates read only mount
 698  *
 699  * This function is called when mounting to erase orphans from the previous
 700  * session. If UBIFS was not unmounted cleanly, then the inodes recorded as
 701  * orphans are deleted.
 702  */
 703 int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
 704 {
 705         int err = 0;
 706
 707         c->max_orphans = tot_avail_orphs(c);
 708
 709         if (!read_only) {
 710                 c->orph_buf = vmalloc(c->leb_size);
 711                 if (!c->orph_buf)
 712                         return -ENOMEM;
 713         }
 714
 715         if (unclean)
 716                 err = kill_orphans(c);
 717         else if (!read_only)
 718                 err = ubifs_clear_orphans(c);
 719
 720         return err;
 721 }
 722
 723 /*
 724  * Everything below is related to debugging.
 725  */
 726
 727 struct check_orphan {
 728         struct rb_node rb;
 729         ino_t inum;
 730 };
 731
 732 struct check_info {
 733         unsigned long last_ino;
 734         unsigned long tot_inos;
 735         unsigned long missing;
 736         unsigned long long leaf_cnt;
 737         struct ubifs_ino_node *node;
 738         struct rb_root root;
 739 };
 740
 741 static int dbg_find_orphan(struct ubifs_info *c, ino_t inum)
 742 {
 743         struct ubifs_orphan *o;
 744         struct rb_node *p;
 745
 746         spin_lock(&c->orphan_lock);
 747         p = c->orph_tree.rb_node;
 748         while (p) {
 749                 o = rb_entry(p, struct ubifs_orphan, rb);
 750                 if (inum < o->inum)
 751                         p = p->rb_left;
 752                 else if (inum > o->inum)
 753                         p = p->rb_right;
 754                 else {
 755                         spin_unlock(&c->orphan_lock);
 756                         return 1;
 757                 }
 758         }
 759         spin_unlock(&c->orphan_lock);
 760         return 0;
 761 }
 762
 763 static int dbg_ins_check_orphan(struct rb_root *root, ino_t inum)
 764 {
 765         struct check_orphan *orphan, *o;
 766         struct rb_node **p, *parent = NULL;
 767
 768         orphan = kzalloc(sizeof(struct check_orphan), GFP_NOFS);
 769         if (!orphan)
 770                 return -ENOMEM;
 771         orphan->inum = inum;
 772
 773         p = &root->rb_node;
 774         while (*p) {
 775                 parent = *p;
 776                 o = rb_entry(parent, struct check_orphan, rb);
 777                 if (inum < o->inum)
 778                         p = &(*p)->rb_left;
 779                 else if (inum > o->inum)
 780                         p = &(*p)->rb_right;
 781                 else {
 782                         kfree(orphan);
 783                         return 0;
 784                 }
 785         }
 786         rb_link_node(&orphan->rb, parent, p);
 787         rb_insert_color(&orphan->rb, root);
 788         return 0;
 789 }
 790
 791 static int dbg_find_check_orphan(struct rb_root *root, ino_t inum)
 792 {
 793         struct check_orphan *o;
 794         struct rb_node *p;
 795
 796         p = root->rb_node;
 797         while (p) {
 798                 o = rb_entry(p, struct check_orphan, rb);
 799                 if (inum < o->inum)
 800                         p = p->rb_left;
 801                 else if (inum > o->inum)
 802                         p = p->rb_right;
 803                 else
 804                         return 1;
 805         }
 806         return 0;
 807 }
 808
 809 static void dbg_free_check_tree(struct rb_root *root)
 810 {
 811         struct rb_node *this = root->rb_node;
 812         struct check_orphan *o;
 813
 814         while (this) {
 815                 if (this->rb_left) {
 816                         this = this->rb_left;
 817                         continue;
 818                 } else if (this->rb_right) {
 819                         this = this->rb_right;
 820                         continue;
 821                 }
 822                 o = rb_entry(this, struct check_orphan, rb);
 823                 this = rb_parent(this);
 824                 if (this) {
 825                         if (this->rb_left == &o->rb)
 826                                 this->rb_left = NULL;
 827                         else
 828                                 this->rb_right = NULL;
 829                 }
 830                 kfree(o);
 831         }
 832 }
 833
 834 static int dbg_orphan_check(struct ubifs_info *c, struct ubifs_zbranch *zbr,
 835                             void *priv)
 836 {
 837         struct check_info *ci = priv;
 838         ino_t inum;
 839         int err;
 840
 841         inum = key_inum(c, &zbr->key);
 842         if (inum != ci->last_ino) {
 843                 /* Lowest node type is the inode node, so it comes first */
 844                 if (key_type(c, &zbr->key) != UBIFS_INO_KEY)
 845                         ubifs_err("found orphan node ino %lu, type %d",
 846                                   (unsigned long)inum, key_type(c, &zbr->key));
 847                 ci->last_ino = inum;
 848                 ci->tot_inos += 1;
 849                 err = ubifs_tnc_read_node(c, zbr, ci->node);
 850                 if (err) {
 851                         ubifs_err("node read failed, error %d", err);
 852                         return err;
 853                 }
 854                 if (ci->node->nlink == 0)
 855                         /* Must be recorded as an orphan */
 856                         if (!dbg_find_check_orphan(&ci->root, inum) &&
 857                             !dbg_find_orphan(c, inum)) {
 858                                 ubifs_err("missing orphan, ino %lu",
 859                                           (unsigned long)inum);
 860                                 ci->missing += 1;
 861                         }
 862         }
 863         ci->leaf_cnt += 1;
 864         return 0;
 865 }
 866
 867 static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
 868 {
 869         struct ubifs_scan_node *snod;
 870         struct ubifs_orph_node *orph;
 871         ino_t inum;
 872         int i, n, err;
 873
 874         list_for_each_entry(snod, &sleb->nodes, list) {
 875                 cond_resched();
 876                 if (snod->type != UBIFS_ORPH_NODE)
 877                         continue;
 878                 orph = snod->node;
 879                 n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
 880                 for (i = 0; i < n; i++) {
 881                         inum = le64_to_cpu(orph->inos[i]);
 882                         err = dbg_ins_check_orphan(&ci->root, inum);
 883                         if (err)
 884                                 return err;
 885                 }
 886         }
 887         return 0;
 888 }
 889
 890 static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
 891 {
 892         int lnum, err = 0;
 893         void *buf;
 894
 895         /* Check no-orphans flag and skip this if no orphans */
 896         if (c->no_orphs)
 897                 return 0;
 898
 899         buf = __vmalloc(c->leb_size, GFP_NOFS, PAGE_KERNEL);
 900         if (!buf) {
 901                 ubifs_err("cannot allocate memory to check orphans");
 902                 return 0;
 903         }
 904
 905         for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
 906                 struct ubifs_scan_leb *sleb;
 907
 908                 sleb = ubifs_scan(c, lnum, 0, buf, 0);
 909                 if (IS_ERR(sleb)) {
 910                         err = PTR_ERR(sleb);
 911                         break;
 912                 }
 913
 914                 err = dbg_read_orphans(ci, sleb);
 915                 ubifs_scan_destroy(sleb);
 916                 if (err)
 917                         break;
 918         }
 919
 920         vfree(buf);
 921         return err;
 922 }
 923
 924 static int dbg_check_orphans(struct ubifs_info *c)
 925 {
 926         struct check_info ci;
 927         int err;
 928
 929         if (!dbg_is_chk_orph(c))
 930                 return 0;
 931
 932         ci.last_ino = 0;
 933         ci.tot_inos = 0;
 934         ci.missing  = 0;
 935         ci.leaf_cnt = 0;
 936         ci.root = RB_ROOT;
 937         ci.node = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
 938         if (!ci.node) {
 939                 ubifs_err("out of memory");
 940                 return -ENOMEM;
 941         }
 942
 943         err = dbg_scan_orphans(c, &ci);
 944         if (err)
 945                 goto out;
 946
 947         err = dbg_walk_index(c, &dbg_orphan_check, NULL, &ci);
 948         if (err) {
 949                 ubifs_err("cannot scan TNC, error %d", err);
 950                 goto out;
 951         }
 952
 953         if (ci.missing) {
 954                 ubifs_err("%lu missing orphan(s)", ci.missing);
 955                 err = -EINVAL;
 956                 goto out;
 957         }
 958
 959         dbg_cmt("last inode number is %lu", ci.last_ino);
 960         dbg_cmt("total number of inodes is %lu", ci.tot_inos);
 961         dbg_cmt("total number of leaf nodes is %llu", ci.leaf_cnt);
 962
 963 out:
 964         dbg_free_check_tree(&ci.root);
 965         kfree(ci.node);
 966         return err;
 967 }