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