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