linux/fs/ubifs/orphan.c
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   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
  55static 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 */
  65int 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 */
 115void 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 */
 167int 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 */
 199static 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 */
 219static 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 */
 239static 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 */
 270static 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 */
 331static 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 */
 365static 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 */
 409static 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 */
 435static 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 */
 461int 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 */
 483int 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 */
 506static 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 */
 553static 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 %d:%d",
 566                                  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 orphan node at %d:%d",
 593                                          cmt_no, sleb->lnum, snod->offs);
 594                                ubifs_dump_node(c, snod->node);
 595                                return -EINVAL;
 596                        }
 597                        dbg_rcvry("out of date LEB %d", sleb->lnum);
 598                        *outofdate = 1;
 599                        return 0;
 600                }
 601
 602                if (first)
 603                        first = 0;
 604
 605                n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
 606                for (i = 0; i < n; i++) {
 607                        inum = le64_to_cpu(orph->inos[i]);
 608                        dbg_rcvry("deleting orphaned inode %lu",
 609                                  (unsigned long)inum);
 610                        err = ubifs_tnc_remove_ino(c, inum);
 611                        if (err)
 612                                return err;
 613                        err = insert_dead_orphan(c, inum);
 614                        if (err)
 615                                return err;
 616                }
 617
 618                *last_cmt_no = cmt_no;
 619                if (le64_to_cpu(orph->cmt_no) & (1ULL << 63)) {
 620                        dbg_rcvry("last orph node for commit %llu at %d:%d",
 621                                  cmt_no, sleb->lnum, snod->offs);
 622                        *last_flagged = 1;
 623                } else
 624                        *last_flagged = 0;
 625        }
 626
 627        return 0;
 628}
 629
 630/**
 631 * kill_orphans - remove all orphan inodes from the index.
 632 * @c: UBIFS file-system description object
 633 *
 634 * If recovery is required, then orphan inodes recorded during the previous
 635 * session (which ended with an unclean unmount) must be deleted from the index.
 636 * This is done by updating the TNC, but since the index is not updated until
 637 * the next commit, the LEBs where the orphan information is recorded are not
 638 * erased until the next commit.
 639 */
 640static int kill_orphans(struct ubifs_info *c)
 641{
 642        unsigned long long last_cmt_no = 0;
 643        int lnum, err = 0, outofdate = 0, last_flagged = 0;
 644
 645        c->ohead_lnum = c->orph_first;
 646        c->ohead_offs = 0;
 647        /* Check no-orphans flag and skip this if no orphans */
 648        if (c->no_orphs) {
 649                dbg_rcvry("no orphans");
 650                return 0;
 651        }
 652        /*
 653         * Orph nodes always start at c->orph_first and are written to each
 654         * successive LEB in turn. Generally unused LEBs will have been unmapped
 655         * but may contain out of date orphan nodes if the unmap didn't go
 656         * through. In addition, the last orphan node written for each commit is
 657         * marked (top bit of orph->cmt_no is set to 1). It is possible that
 658         * there are orphan nodes from the next commit (i.e. the commit did not
 659         * complete successfully). In that case, no orphans will have been lost
 660         * due to the way that orphans are written, and any orphans added will
 661         * be valid orphans anyway and so can be deleted.
 662         */
 663        for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
 664                struct ubifs_scan_leb *sleb;
 665
 666                dbg_rcvry("LEB %d", lnum);
 667                sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
 668                if (IS_ERR(sleb)) {
 669                        if (PTR_ERR(sleb) == -EUCLEAN)
 670                                sleb = ubifs_recover_leb(c, lnum, 0,
 671                                                         c->sbuf, -1);
 672                        if (IS_ERR(sleb)) {
 673                                err = PTR_ERR(sleb);
 674                                break;
 675                        }
 676                }
 677                err = do_kill_orphans(c, sleb, &last_cmt_no, &outofdate,
 678                                      &last_flagged);
 679                if (err || outofdate) {
 680                        ubifs_scan_destroy(sleb);
 681                        break;
 682                }
 683                if (sleb->endpt) {
 684                        c->ohead_lnum = lnum;
 685                        c->ohead_offs = sleb->endpt;
 686                }
 687                ubifs_scan_destroy(sleb);
 688        }
 689        return err;
 690}
 691
 692/**
 693 * ubifs_mount_orphans - delete orphan inodes and erase LEBs that recorded them.
 694 * @c: UBIFS file-system description object
 695 * @unclean: indicates recovery from unclean unmount
 696 * @read_only: indicates read only mount
 697 *
 698 * This function is called when mounting to erase orphans from the previous
 699 * session. If UBIFS was not unmounted cleanly, then the inodes recorded as
 700 * orphans are deleted.
 701 */
 702int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
 703{
 704        int err = 0;
 705
 706        c->max_orphans = tot_avail_orphs(c);
 707
 708        if (!read_only) {
 709                c->orph_buf = vmalloc(c->leb_size);
 710                if (!c->orph_buf)
 711                        return -ENOMEM;
 712        }
 713
 714        if (unclean)
 715                err = kill_orphans(c);
 716        else if (!read_only)
 717                err = ubifs_clear_orphans(c);
 718
 719        return err;
 720}
 721
 722/*
 723 * Everything below is related to debugging.
 724 */
 725
 726struct check_orphan {
 727        struct rb_node rb;
 728        ino_t inum;
 729};
 730
 731struct check_info {
 732        unsigned long last_ino;
 733        unsigned long tot_inos;
 734        unsigned long missing;
 735        unsigned long long leaf_cnt;
 736        struct ubifs_ino_node *node;
 737        struct rb_root root;
 738};
 739
 740static int dbg_find_orphan(struct ubifs_info *c, ino_t inum)
 741{
 742        struct ubifs_orphan *o;
 743        struct rb_node *p;
 744
 745        spin_lock(&c->orphan_lock);
 746        p = c->orph_tree.rb_node;
 747        while (p) {
 748                o = rb_entry(p, struct ubifs_orphan, rb);
 749                if (inum < o->inum)
 750                        p = p->rb_left;
 751                else if (inum > o->inum)
 752                        p = p->rb_right;
 753                else {
 754                        spin_unlock(&c->orphan_lock);
 755                        return 1;
 756                }
 757        }
 758        spin_unlock(&c->orphan_lock);
 759        return 0;
 760}
 761
 762static int dbg_ins_check_orphan(struct rb_root *root, ino_t inum)
 763{
 764        struct check_orphan *orphan, *o;
 765        struct rb_node **p, *parent = NULL;
 766
 767        orphan = kzalloc(sizeof(struct check_orphan), GFP_NOFS);
 768        if (!orphan)
 769                return -ENOMEM;
 770        orphan->inum = inum;
 771
 772        p = &root->rb_node;
 773        while (*p) {
 774                parent = *p;
 775                o = rb_entry(parent, struct check_orphan, rb);
 776                if (inum < o->inum)
 777                        p = &(*p)->rb_left;
 778                else if (inum > o->inum)
 779                        p = &(*p)->rb_right;
 780                else {
 781                        kfree(orphan);
 782                        return 0;
 783                }
 784        }
 785        rb_link_node(&orphan->rb, parent, p);
 786        rb_insert_color(&orphan->rb, root);
 787        return 0;
 788}
 789
 790static int dbg_find_check_orphan(struct rb_root *root, ino_t inum)
 791{
 792        struct check_orphan *o;
 793        struct rb_node *p;
 794
 795        p = root->rb_node;
 796        while (p) {
 797                o = rb_entry(p, struct check_orphan, rb);
 798                if (inum < o->inum)
 799                        p = p->rb_left;
 800                else if (inum > o->inum)
 801                        p = p->rb_right;
 802                else
 803                        return 1;
 804        }
 805        return 0;
 806}
 807
 808static void dbg_free_check_tree(struct rb_root *root)
 809{
 810        struct rb_node *this = root->rb_node;
 811        struct check_orphan *o;
 812
 813        while (this) {
 814                if (this->rb_left) {
 815                        this = this->rb_left;
 816                        continue;
 817                } else if (this->rb_right) {
 818                        this = this->rb_right;
 819                        continue;
 820                }
 821                o = rb_entry(this, struct check_orphan, rb);
 822                this = rb_parent(this);
 823                if (this) {
 824                        if (this->rb_left == &o->rb)
 825                                this->rb_left = NULL;
 826                        else
 827                                this->rb_right = NULL;
 828                }
 829                kfree(o);
 830        }
 831}
 832
 833static int dbg_orphan_check(struct ubifs_info *c, struct ubifs_zbranch *zbr,
 834                            void *priv)
 835{
 836        struct check_info *ci = priv;
 837        ino_t inum;
 838        int err;
 839
 840        inum = key_inum(c, &zbr->key);
 841        if (inum != ci->last_ino) {
 842                /* Lowest node type is the inode node, so it comes first */
 843                if (key_type(c, &zbr->key) != UBIFS_INO_KEY)
 844                        ubifs_err("found orphan node ino %lu, type %d",
 845                                  (unsigned long)inum, key_type(c, &zbr->key));
 846                ci->last_ino = inum;
 847                ci->tot_inos += 1;
 848                err = ubifs_tnc_read_node(c, zbr, ci->node);
 849                if (err) {
 850                        ubifs_err("node read failed, error %d", err);
 851                        return err;
 852                }
 853                if (ci->node->nlink == 0)
 854                        /* Must be recorded as an orphan */
 855                        if (!dbg_find_check_orphan(&ci->root, inum) &&
 856                            !dbg_find_orphan(c, inum)) {
 857                                ubifs_err("missing orphan, ino %lu",
 858                                          (unsigned long)inum);
 859                                ci->missing += 1;
 860                        }
 861        }
 862        ci->leaf_cnt += 1;
 863        return 0;
 864}
 865
 866static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
 867{
 868        struct ubifs_scan_node *snod;
 869        struct ubifs_orph_node *orph;
 870        ino_t inum;
 871        int i, n, err;
 872
 873        list_for_each_entry(snod, &sleb->nodes, list) {
 874                cond_resched();
 875                if (snod->type != UBIFS_ORPH_NODE)
 876                        continue;
 877                orph = snod->node;
 878                n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
 879                for (i = 0; i < n; i++) {
 880                        inum = le64_to_cpu(orph->inos[i]);
 881                        err = dbg_ins_check_orphan(&ci->root, inum);
 882                        if (err)
 883                                return err;
 884                }
 885        }
 886        return 0;
 887}
 888
 889static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
 890{
 891        int lnum, err = 0;
 892        void *buf;
 893
 894        /* Check no-orphans flag and skip this if no orphans */
 895        if (c->no_orphs)
 896                return 0;
 897
 898        buf = __vmalloc(c->leb_size, GFP_NOFS, PAGE_KERNEL);
 899        if (!buf) {
 900                ubifs_err("cannot allocate memory to check orphans");
 901                return 0;
 902        }
 903
 904        for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
 905                struct ubifs_scan_leb *sleb;
 906
 907                sleb = ubifs_scan(c, lnum, 0, buf, 0);
 908                if (IS_ERR(sleb)) {
 909                        err = PTR_ERR(sleb);
 910                        break;
 911                }
 912
 913                err = dbg_read_orphans(ci, sleb);
 914                ubifs_scan_destroy(sleb);
 915                if (err)
 916                        break;
 917        }
 918
 919        vfree(buf);
 920        return err;
 921}
 922
 923static int dbg_check_orphans(struct ubifs_info *c)
 924{
 925        struct check_info ci;
 926        int err;
 927
 928        if (!dbg_is_chk_orph(c))
 929                return 0;
 930
 931        ci.last_ino = 0;
 932        ci.tot_inos = 0;
 933        ci.missing  = 0;
 934        ci.leaf_cnt = 0;
 935        ci.root = RB_ROOT;
 936        ci.node = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
 937        if (!ci.node) {
 938                ubifs_err("out of memory");
 939                return -ENOMEM;
 940        }
 941
 942        err = dbg_scan_orphans(c, &ci);
 943        if (err)
 944                goto out;
 945
 946        err = dbg_walk_index(c, &dbg_orphan_check, NULL, &ci);
 947        if (err) {
 948                ubifs_err("cannot scan TNC, error %d", err);
 949                goto out;
 950        }
 951
 952        if (ci.missing) {
 953                ubifs_err("%lu missing orphan(s)", ci.missing);
 954                err = -EINVAL;
 955                goto out;
 956        }
 957
 958        dbg_cmt("last inode number is %lu", ci.last_ino);
 959        dbg_cmt("total number of inodes is %lu", ci.tot_inos);
 960        dbg_cmt("total number of leaf nodes is %llu", ci.leaf_cnt);
 961
 962out:
 963        dbg_free_check_tree(&ci.root);
 964        kfree(ci.node);
 965        return err;
 966}
 967
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