orphan.c

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/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Author: Adrian Hunter
 */

#include "ubifs.h"

/*
 * An orphan is an inode number whose inode node has been committed to the index
 * with a link count of zero. That happens when an open file is deleted
 * (unlinked) and then a commit is run. In the normal course of events the inode
 * would be deleted when the file is closed. However in the case of an unclean
 * unmount, orphans need to be accounted for. After an unclean unmount, the
 * orphans' inodes must be deleted which means either scanning the entire index
 * looking for them, or keeping a list on flash somewhere. This unit implements
 * the latter approach.
 *
 * The orphan area is a fixed number of LEBs situated between the LPT area and
 * the main area. The number of orphan area LEBs is specified when the file
 * system is created. The minimum number is 1. The size of the orphan area
 * should be so that it can hold the maximum number of orphans that are expected
 * to ever exist at one time.
 *
 * The number of orphans that can fit in a LEB is:
 *
 *         (c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64)
 *
 * For example: a 15872 byte LEB can fit 1980 orphans so 1 LEB may be enough.
 *
 * Orphans are accumulated in a rb-tree. When an inode's link count drops to
 * zero, the inode number is added to the rb-tree. It is removed from the tree
 * when the inode is deleted.  Any new orphans that are in the orphan tree when
 * the commit is run, are written to the orphan area in 1 or more orphan nodes.
 * If the orphan area is full, it is consolidated to make space.  There is
 * always enough space because validation prevents the user from creating more
 * than the maximum number of orphans allowed.
 */

static int dbg_check_orphans(struct ubifs_info *c);

int ubifs_add_orphan(struct ubifs_info *c, ino_t inum)
{
    struct ubifs_orphan *orphan, *o;
    struct rb_node **p, *parent = NULL;

    orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_NOFS);
    if (!orphan)
        return -ENOMEM;
    orphan->inum = inum;
    orphan->new = 1;

    spin_lock(&c->orphan_lock);
    if (c->tot_orphans >= c->max_orphans) {
        spin_unlock(&c->orphan_lock);
        kfree(orphan);
        return -ENFILE;
    }
    p = &c->orph_tree.rb_node;
    while (*p) {
        parent = *p;
        o = rb_entry(parent, struct ubifs_orphan, rb);
        if (inum < o->inum)
            p = &(*p)->rb_left;
        else if (inum > o->inum)
            p = &(*p)->rb_right;
        else {
            ubifs_err("orphaned twice");
            spin_unlock(&c->orphan_lock);
            kfree(orphan);
            return 0;
        }
    }
    c->tot_orphans += 1;
    c->new_orphans += 1;
    rb_link_node(&orphan->rb, parent, p);
    rb_insert_color(&orphan->rb, &c->orph_tree);
    list_add_tail(&orphan->list, &c->orph_list);
    list_add_tail(&orphan->new_list, &c->orph_new);
    spin_unlock(&c->orphan_lock);
    dbg_gen("ino %lu", (unsigned long)inum);
    return 0;
}

void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
{
    struct ubifs_orphan *o;
    struct rb_node *p;

    spin_lock(&c->orphan_lock);
    p = c->orph_tree.rb_node;
    while (p) {
        o = rb_entry(p, struct ubifs_orphan, rb);
        if (inum < o->inum)
            p = p->rb_left;
        else if (inum > o->inum)
            p = p->rb_right;
        else {
            if (o->dnext) {
                spin_unlock(&c->orphan_lock);
                dbg_gen("deleted twice ino %lu",
                    (unsigned long)inum);
                return;
            }
            if (o->cnext) {
                o->dnext = c->orph_dnext;
                c->orph_dnext = o;
                spin_unlock(&c->orphan_lock);
                dbg_gen("delete later ino %lu",
                    (unsigned long)inum);
                return;
            }
            rb_erase(p, &c->orph_tree);
            list_del(&o->list);
            c->tot_orphans -= 1;
            if (o->new) {
                list_del(&o->new_list);
                c->new_orphans -= 1;
            }
            spin_unlock(&c->orphan_lock);
            kfree(o);
            dbg_gen("inum %lu", (unsigned long)inum);
            return;
        }
    }
    spin_unlock(&c->orphan_lock);
    ubifs_err("missing orphan ino %lu", (unsigned long)inum);
    dump_stack();
}

int ubifs_orphan_start_commit(struct ubifs_info *c)
{
    struct ubifs_orphan *orphan, **last;

    spin_lock(&c->orphan_lock);
    last = &c->orph_cnext;
    list_for_each_entry(orphan, &c->orph_new, new_list) {
        ubifs_assert(orphan->new);
        orphan->new = 0;
        *last = orphan;
        last = &orphan->cnext;
    }
    *last = NULL;
    c->cmt_orphans = c->new_orphans;
    c->new_orphans = 0;
    dbg_cmt("%d orphans to commit", c->cmt_orphans);
    INIT_LIST_HEAD(&c->orph_new);
    if (c->tot_orphans == 0)
        c->no_orphs = 1;
    else
        c->no_orphs = 0;
    spin_unlock(&c->orphan_lock);
    return 0;
}

static int avail_orphs(struct ubifs_info *c)
{
    int avail_lebs, avail, gap;

    avail_lebs = c->orph_lebs - (c->ohead_lnum - c->orph_first) - 1;
    avail = avail_lebs *
           ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
    gap = c->leb_size - c->ohead_offs;
    if (gap >= UBIFS_ORPH_NODE_SZ + sizeof(__le64))
        avail += (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
    return avail;
}

static int tot_avail_orphs(struct ubifs_info *c)
{
    int avail_lebs, avail;

    avail_lebs = c->orph_lebs;
    avail = avail_lebs *
           ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
    return avail / 2;
}

static int do_write_orph_node(struct ubifs_info *c, int len, int atomic)
{
    int err = 0;

    if (atomic) {
        ubifs_assert(c->ohead_offs == 0);
        ubifs_prepare_node(c, c->orph_buf, len, 1);
        len = ALIGN(len, c->min_io_size);
        err = ubifs_leb_change(c, c->ohead_lnum, c->orph_buf, len);
    } else {
        if (c->ohead_offs == 0) {
            /* Ensure LEB has been unmapped */
            err = ubifs_leb_unmap(c, c->ohead_lnum);
            if (err)
                return err;
        }
        err = ubifs_write_node(c, c->orph_buf, len, c->ohead_lnum,
                       c->ohead_offs);
    }
    return err;
}

static int write_orph_node(struct ubifs_info *c, int atomic)
{
    struct ubifs_orphan *orphan, *cnext;
    struct ubifs_orph_node *orph;
    int gap, err, len, cnt, i;

    ubifs_assert(c->cmt_orphans > 0);
    gap = c->leb_size - c->ohead_offs;
    if (gap < UBIFS_ORPH_NODE_SZ + sizeof(__le64)) {
        c->ohead_lnum += 1;
        c->ohead_offs = 0;
        gap = c->leb_size;
        if (c->ohead_lnum > c->orph_last) {
            /*
             * We limit the number of orphans so that this should
             * never happen.
             */
            ubifs_err("out of space in orphan area");
            return -EINVAL;
        }
    }
    cnt = (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
    if (cnt > c->cmt_orphans)
        cnt = c->cmt_orphans;
    len = UBIFS_ORPH_NODE_SZ + cnt * sizeof(__le64);
    ubifs_assert(c->orph_buf);
    orph = c->orph_buf;
    orph->ch.node_type = UBIFS_ORPH_NODE;
    spin_lock(&c->orphan_lock);
    cnext = c->orph_cnext;
    for (i = 0; i < cnt; i++) {
        orphan = cnext;
        orph->inos[i] = cpu_to_le64(orphan->inum);
        cnext = orphan->cnext;
        orphan->cnext = NULL;
    }
    c->orph_cnext = cnext;
    c->cmt_orphans -= cnt;
    spin_unlock(&c->orphan_lock);
    if (c->cmt_orphans)
        orph->cmt_no = cpu_to_le64(c->cmt_no);
    else
        /* Mark the last node of the commit */
        orph->cmt_no = cpu_to_le64((c->cmt_no) | (1ULL << 63));
    ubifs_assert(c->ohead_offs + len <= c->leb_size);
    ubifs_assert(c->ohead_lnum >= c->orph_first);
    ubifs_assert(c->ohead_lnum <= c->orph_last);
    err = do_write_orph_node(c, len, atomic);
    c->ohead_offs += ALIGN(len, c->min_io_size);
    c->ohead_offs = ALIGN(c->ohead_offs, 8);
    return err;
}

static int write_orph_nodes(struct ubifs_info *c, int atomic)
{
    int err;

    while (c->cmt_orphans > 0) {
        err = write_orph_node(c, atomic);
        if (err)
            return err;
    }
    if (atomic) {
        int lnum;

        /* Unmap any unused LEBs after consolidation */
        lnum = c->ohead_lnum + 1;
        for (lnum = c->ohead_lnum + 1; lnum <= c->orph_last; lnum++) {
            err = ubifs_leb_unmap(c, lnum);
            if (err)
                return err;
        }
    }
    return 0;
}

static int consolidate(struct ubifs_info *c)
{
    int tot_avail = tot_avail_orphs(c), err = 0;

    spin_lock(&c->orphan_lock);
    dbg_cmt("there is space for %d orphans and there are %d",
        tot_avail, c->tot_orphans);
    if (c->tot_orphans - c->new_orphans <= tot_avail) {
        struct ubifs_orphan *orphan, **last;
        int cnt = 0;

        /* Change the cnext list to include all non-new orphans */
        last = &c->orph_cnext;
        list_for_each_entry(orphan, &c->orph_list, list) {
            if (orphan->new)
                continue;
            *last = orphan;
            last = &orphan->cnext;
            cnt += 1;
        }
        *last = NULL;
        ubifs_assert(cnt == c->tot_orphans - c->new_orphans);
        c->cmt_orphans = cnt;
        c->ohead_lnum = c->orph_first;
        c->ohead_offs = 0;
    } else {
        /*
         * We limit the number of orphans so that this should
         * never happen.
         */
        ubifs_err("out of space in orphan area");
        err = -EINVAL;
    }
    spin_unlock(&c->orphan_lock);
    return err;
}

static int commit_orphans(struct ubifs_info *c)
{
    int avail, atomic = 0, err;

    ubifs_assert(c->cmt_orphans > 0);
    avail = avail_orphs(c);
    if (avail < c->cmt_orphans) {
        /* Not enough space to write new orphans, so consolidate */
        err = consolidate(c);
        if (err)
            return err;
        atomic = 1;
    }
    err = write_orph_nodes(c, atomic);
    return err;
}

static void erase_deleted(struct ubifs_info *c)
{
    struct ubifs_orphan *orphan, *dnext;

    spin_lock(&c->orphan_lock);
    dnext = c->orph_dnext;
    while (dnext) {
        orphan = dnext;
        dnext = orphan->dnext;
        ubifs_assert(!orphan->new);
        rb_erase(&orphan->rb, &c->orph_tree);
        list_del(&orphan->list);
        c->tot_orphans -= 1;
        dbg_gen("deleting orphan ino %lu", (unsigned long)orphan->inum);
        kfree(orphan);
    }
    c->orph_dnext = NULL;
    spin_unlock(&c->orphan_lock);
}

int ubifs_orphan_end_commit(struct ubifs_info *c)
{
    int err;

    if (c->cmt_orphans != 0) {
        err = commit_orphans(c);
        if (err)
            return err;
    }
    erase_deleted(c);
    err = dbg_check_orphans(c);
    return err;
}

int ubifs_clear_orphans(struct ubifs_info *c)
{
    int lnum, err;

    for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
        err = ubifs_leb_unmap(c, lnum);
        if (err)
            return err;
    }
    c->ohead_lnum = c->orph_first;
    c->ohead_offs = 0;
    return 0;
}

static int insert_dead_orphan(struct ubifs_info *c, ino_t inum)
{
    struct ubifs_orphan *orphan, *o;
    struct rb_node **p, *parent = NULL;

    orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_KERNEL);
    if (!orphan)
        return -ENOMEM;
    orphan->inum = inum;

    p = &c->orph_tree.rb_node;
    while (*p) {
        parent = *p;
        o = rb_entry(parent, struct ubifs_orphan, rb);
        if (inum < o->inum)
            p = &(*p)->rb_left;
        else if (inum > o->inum)
            p = &(*p)->rb_right;
        else {
            /* Already added - no problem */
            kfree(orphan);
            return 0;
        }
    }
    c->tot_orphans += 1;
    rb_link_node(&orphan->rb, parent, p);
    rb_insert_color(&orphan->rb, &c->orph_tree);
    list_add_tail(&orphan->list, &c->orph_list);
    orphan->dnext = c->orph_dnext;
    c->orph_dnext = orphan;
    dbg_mnt("ino %lu, new %d, tot %d", (unsigned long)inum,
        c->new_orphans, c->tot_orphans);
    return 0;
}

static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
               unsigned long long *last_cmt_no, int *outofdate,
               int *last_flagged)
{
    struct ubifs_scan_node *snod;
    struct ubifs_orph_node *orph;
    unsigned long long cmt_no;
    ino_t inum;
    int i, n, err, first = 1;

    list_for_each_entry(snod, &sleb->nodes, list) {
        if (snod->type != UBIFS_ORPH_NODE) {
            ubifs_err("invalid node type %d in orphan area at %d:%d",
                  snod->type, sleb->lnum, snod->offs);
            ubifs_dump_node(c, snod->node);
            return -EINVAL;
        }

        orph = snod->node;

        /* Check commit number */
        cmt_no = le64_to_cpu(orph->cmt_no) & LLONG_MAX;
        /*
         * The commit number on the master node may be less, because
         * of a failed commit. If there are several failed commits in a
         * row, the commit number written on orphan nodes will continue
         * to increase (because the commit number is adjusted here) even
         * though the commit number on the master node stays the same
         * because the master node has not been re-written.
         */
        if (cmt_no > c->cmt_no)
            c->cmt_no = cmt_no;
        if (cmt_no < *last_cmt_no && *last_flagged) {
            /*
             * The last orphan node had a higher commit number and
             * was flagged as the last written for that commit
             * number. That makes this orphan node, out of date.
             */
            if (!first) {
                ubifs_err("out of order commit number %llu in orphan node at %d:%d",
                      cmt_no, sleb->lnum, snod->offs);
                ubifs_dump_node(c, snod->node);
                return -EINVAL;
            }
            dbg_rcvry("out of date LEB %d", sleb->lnum);
            *outofdate = 1;
            return 0;
        }

        if (first)
            first = 0;

        n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
        for (i = 0; i < n; i++) {
            inum = le64_to_cpu(orph->inos[i]);
            dbg_rcvry("deleting orphaned inode %lu",
                  (unsigned long)inum);
            err = ubifs_tnc_remove_ino(c, inum);
            if (err)
                return err;
            err = insert_dead_orphan(c, inum);
            if (err)
                return err;
        }

        *last_cmt_no = cmt_no;
        if (le64_to_cpu(orph->cmt_no) & (1ULL << 63)) {
            dbg_rcvry("last orph node for commit %llu at %d:%d",
                  cmt_no, sleb->lnum, snod->offs);
            *last_flagged = 1;
        } else
            *last_flagged = 0;
    }

    return 0;
}

static int kill_orphans(struct ubifs_info *c)
{
    unsigned long long last_cmt_no = 0;
    int lnum, err = 0, outofdate = 0, last_flagged = 0;

    c->ohead_lnum = c->orph_first;
    c->ohead_offs = 0;
    /* Check no-orphans flag and skip this if no orphans */
    if (c->no_orphs) {
        dbg_rcvry("no orphans");
        return 0;
    }
    /*
     * Orph nodes always start at c->orph_first and are written to each
     * successive LEB in turn. Generally unused LEBs will have been unmapped
     * but may contain out of date orphan nodes if the unmap didn't go
     * through. In addition, the last orphan node written for each commit is
     * marked (top bit of orph->cmt_no is set to 1). It is possible that
     * there are orphan nodes from the next commit (i.e. the commit did not
     * complete successfully). In that case, no orphans will have been lost
     * due to the way that orphans are written, and any orphans added will
     * be valid orphans anyway and so can be deleted.
     */
    for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
        struct ubifs_scan_leb *sleb;

        dbg_rcvry("LEB %d", lnum);
        sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
        if (IS_ERR(sleb)) {
            if (PTR_ERR(sleb) == -EUCLEAN)
                sleb = ubifs_recover_leb(c, lnum, 0,
                             c->sbuf, -1);
            if (IS_ERR(sleb)) {
                err = PTR_ERR(sleb);
                break;
            }
        }
        err = do_kill_orphans(c, sleb, &last_cmt_no, &outofdate,
                      &last_flagged);
        if (err || outofdate) {
            ubifs_scan_destroy(sleb);
            break;
        }
        if (sleb->endpt) {
            c->ohead_lnum = lnum;
            c->ohead_offs = sleb->endpt;
        }
        ubifs_scan_destroy(sleb);
    }
    return err;
}

int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
{
    int err = 0;

    c->max_orphans = tot_avail_orphs(c);

    if (!read_only) {
        c->orph_buf = vmalloc(c->leb_size);
        if (!c->orph_buf)
            return -ENOMEM;
    }

    if (unclean)
        err = kill_orphans(c);
    else if (!read_only)
        err = ubifs_clear_orphans(c);

    return err;
}

/*
 * Everything below is related to debugging.
 */

struct check_orphan {
    struct rb_node rb;
    ino_t inum;
};

struct check_info {
    unsigned long last_ino;
    unsigned long tot_inos;
    unsigned long missing;
    unsigned long long leaf_cnt;
    struct ubifs_ino_node *node;
    struct rb_root root;
};

static int dbg_find_orphan(struct ubifs_info *c, ino_t inum)
{
    struct ubifs_orphan *o;
    struct rb_node *p;

    spin_lock(&c->orphan_lock);
    p = c->orph_tree.rb_node;
    while (p) {
        o = rb_entry(p, struct ubifs_orphan, rb);
        if (inum < o->inum)
            p = p->rb_left;
        else if (inum > o->inum)
            p = p->rb_right;
        else {
            spin_unlock(&c->orphan_lock);
            return 1;
        }
    }
    spin_unlock(&c->orphan_lock);
    return 0;
}

static int dbg_ins_check_orphan(struct rb_root *root, ino_t inum)
{
    struct check_orphan *orphan, *o;
    struct rb_node **p, *parent = NULL;

    orphan = kzalloc(sizeof(struct check_orphan), GFP_NOFS);
    if (!orphan)
        return -ENOMEM;
    orphan->inum = inum;

    p = &root->rb_node;
    while (*p) {
        parent = *p;
        o = rb_entry(parent, struct check_orphan, rb);
        if (inum < o->inum)
            p = &(*p)->rb_left;
        else if (inum > o->inum)
            p = &(*p)->rb_right;
        else {
            kfree(orphan);
            return 0;
        }
    }
    rb_link_node(&orphan->rb, parent, p);
    rb_insert_color(&orphan->rb, root);
    return 0;
}

static int dbg_find_check_orphan(struct rb_root *root, ino_t inum)
{
    struct check_orphan *o;
    struct rb_node *p;

    p = root->rb_node;
    while (p) {
        o = rb_entry(p, struct check_orphan, rb);
        if (inum < o->inum)
            p = p->rb_left;
        else if (inum > o->inum)
            p = p->rb_right;
        else
            return 1;
    }
    return 0;
}

static void dbg_free_check_tree(struct rb_root *root)
{
    struct rb_node *this = root->rb_node;
    struct check_orphan *o;

    while (this) {
        if (this->rb_left) {
            this = this->rb_left;
            continue;
        } else if (this->rb_right) {
            this = this->rb_right;
            continue;
        }
        o = rb_entry(this, struct check_orphan, rb);
        this = rb_parent(this);
        if (this) {
            if (this->rb_left == &o->rb)
                this->rb_left = NULL;
            else
                this->rb_right = NULL;
        }
        kfree(o);
    }
}

static int dbg_orphan_check(struct ubifs_info *c, struct ubifs_zbranch *zbr,
                void *priv)
{
    struct check_info *ci = priv;
    ino_t inum;
    int err;

    inum = key_inum(c, &zbr->key);
    if (inum != ci->last_ino) {
        /* Lowest node type is the inode node, so it comes first */
        if (key_type(c, &zbr->key) != UBIFS_INO_KEY)
            ubifs_err("found orphan node ino %lu, type %d",
                  (unsigned long)inum, key_type(c, &zbr->key));
        ci->last_ino = inum;
        ci->tot_inos += 1;
        err = ubifs_tnc_read_node(c, zbr, ci->node);
        if (err) {
            ubifs_err("node read failed, error %d", err);
            return err;
        }
        if (ci->node->nlink == 0)
            /* Must be recorded as an orphan */
            if (!dbg_find_check_orphan(&ci->root, inum) &&
                !dbg_find_orphan(c, inum)) {
                ubifs_err("missing orphan, ino %lu",
                      (unsigned long)inum);
                ci->missing += 1;
            }
    }
    ci->leaf_cnt += 1;
    return 0;
}

static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
{
    struct ubifs_scan_node *snod;
    struct ubifs_orph_node *orph;
    ino_t inum;
    int i, n, err;

    list_for_each_entry(snod, &sleb->nodes, list) {
        cond_resched();
        if (snod->type != UBIFS_ORPH_NODE)
            continue;
        orph = snod->node;
        n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
        for (i = 0; i < n; i++) {
            inum = le64_to_cpu(orph->inos[i]);
            err = dbg_ins_check_orphan(&ci->root, inum);
            if (err)
                return err;
        }
    }
    return 0;
}

static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
{
    int lnum, err = 0;
    void *buf;

    /* Check no-orphans flag and skip this if no orphans */
    if (c->no_orphs)
        return 0;

    buf = __vmalloc(c->leb_size, GFP_NOFS, PAGE_KERNEL);
    if (!buf) {
        ubifs_err("cannot allocate memory to check orphans");
        return 0;
    }

    for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
        struct ubifs_scan_leb *sleb;

        sleb = ubifs_scan(c, lnum, 0, buf, 0);
        if (IS_ERR(sleb)) {
            err = PTR_ERR(sleb);
            break;
        }

        err = dbg_read_orphans(ci, sleb);
        ubifs_scan_destroy(sleb);
        if (err)
            break;
    }

    vfree(buf);
    return err;
}

static int dbg_check_orphans(struct ubifs_info *c)
{
    struct check_info ci;
    int err;

    if (!dbg_is_chk_orph(c))
        return 0;

    ci.last_ino = 0;
    ci.tot_inos = 0;
    ci.missing  = 0;
    ci.leaf_cnt = 0;
    ci.root = RB_ROOT;
    ci.node = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
    if (!ci.node) {
        ubifs_err("out of memory");
        return -ENOMEM;
    }

    err = dbg_scan_orphans(c, &ci);
    if (err)
        goto out;

    err = dbg_walk_index(c, &dbg_orphan_check, NULL, &ci);
    if (err) {
        ubifs_err("cannot scan TNC, error %d", err);
        goto out;
    }

    if (ci.missing) {
        ubifs_err("%lu missing orphan(s)", ci.missing);
        err = -EINVAL;
        goto out;
    }

    dbg_cmt("last inode number is %lu", ci.last_ino);
    dbg_cmt("total number of inodes is %lu", ci.tot_inos);
    dbg_cmt("total number of leaf nodes is %llu", ci.leaf_cnt);

out:
    dbg_free_check_tree(&ci.root);
    kfree(ci.node);
    return err;
}