lpt_commit.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
 *
 * Authors: Adrian Hunter
 *          Artem Bityutskiy (Битюцкий Артём)
 */

/*
 * This file implements commit-related functionality of the LEB properties
 * subsystem.
 */

#include <linux/crc16.h>
#include <linux/slab.h>
#include <linux/random.h>
#include "ubifs.h"

static int dbg_populate_lsave(struct ubifs_info *c);

static struct ubifs_cnode *first_dirty_cnode(struct ubifs_nnode *nnode)
{
    ubifs_assert(nnode);
    while (1) {
        int i, cont = 0;

        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
            struct ubifs_cnode *cnode;

            cnode = nnode->nbranch[i].cnode;
            if (cnode &&
                test_bit(DIRTY_CNODE, &cnode->flags)) {
                if (cnode->level == 0)
                    return cnode;
                nnode = (struct ubifs_nnode *)cnode;
                cont = 1;
                break;
            }
        }
        if (!cont)
            return (struct ubifs_cnode *)nnode;
    }
}

static struct ubifs_cnode *next_dirty_cnode(struct ubifs_cnode *cnode)
{
    struct ubifs_nnode *nnode;
    int i;

    ubifs_assert(cnode);
    nnode = cnode->parent;
    if (!nnode)
        return NULL;
    for (i = cnode->iip + 1; i < UBIFS_LPT_FANOUT; i++) {
        cnode = nnode->nbranch[i].cnode;
        if (cnode && test_bit(DIRTY_CNODE, &cnode->flags)) {
            if (cnode->level == 0)
                return cnode; /* cnode is a pnode */
            /* cnode is a nnode */
            return first_dirty_cnode((struct ubifs_nnode *)cnode);
        }
    }
    return (struct ubifs_cnode *)nnode;
}

static int get_cnodes_to_commit(struct ubifs_info *c)
{
    struct ubifs_cnode *cnode, *cnext;
    int cnt = 0;

    if (!c->nroot)
        return 0;

    if (!test_bit(DIRTY_CNODE, &c->nroot->flags))
        return 0;

    c->lpt_cnext = first_dirty_cnode(c->nroot);
    cnode = c->lpt_cnext;
    if (!cnode)
        return 0;
    cnt += 1;
    while (1) {
        ubifs_assert(!test_bit(COW_CNODE, &cnode->flags));
        __set_bit(COW_CNODE, &cnode->flags);
        cnext = next_dirty_cnode(cnode);
        if (!cnext) {
            cnode->cnext = c->lpt_cnext;
            break;
        }
        cnode->cnext = cnext;
        cnode = cnext;
        cnt += 1;
    }
    dbg_cmt("committing %d cnodes", cnt);
    dbg_lp("committing %d cnodes", cnt);
    ubifs_assert(cnt == c->dirty_nn_cnt + c->dirty_pn_cnt);
    return cnt;
}

static void upd_ltab(struct ubifs_info *c, int lnum, int free, int dirty)
{
    dbg_lp("LEB %d free %d dirty %d to %d +%d",
           lnum, c->ltab[lnum - c->lpt_first].free,
           c->ltab[lnum - c->lpt_first].dirty, free, dirty);
    ubifs_assert(lnum >= c->lpt_first && lnum <= c->lpt_last);
    c->ltab[lnum - c->lpt_first].free = free;
    c->ltab[lnum - c->lpt_first].dirty += dirty;
}

static int alloc_lpt_leb(struct ubifs_info *c, int *lnum)
{
    int i, n;

    n = *lnum - c->lpt_first + 1;
    for (i = n; i < c->lpt_lebs; i++) {
        if (c->ltab[i].tgc || c->ltab[i].cmt)
            continue;
        if (c->ltab[i].free == c->leb_size) {
            c->ltab[i].cmt = 1;
            *lnum = i + c->lpt_first;
            return 0;
        }
    }

    for (i = 0; i < n; i++) {
        if (c->ltab[i].tgc || c->ltab[i].cmt)
            continue;
        if (c->ltab[i].free == c->leb_size) {
            c->ltab[i].cmt = 1;
            *lnum = i + c->lpt_first;
            return 0;
        }
    }
    return -ENOSPC;
}

static int layout_cnodes(struct ubifs_info *c)
{
    int lnum, offs, len, alen, done_lsave, done_ltab, err;
    struct ubifs_cnode *cnode;

    err = dbg_chk_lpt_sz(c, 0, 0);
    if (err)
        return err;
    cnode = c->lpt_cnext;
    if (!cnode)
        return 0;
    lnum = c->nhead_lnum;
    offs = c->nhead_offs;
    /* Try to place lsave and ltab nicely */
    done_lsave = !c->big_lpt;
    done_ltab = 0;
    if (!done_lsave && offs + c->lsave_sz <= c->leb_size) {
        done_lsave = 1;
        c->lsave_lnum = lnum;
        c->lsave_offs = offs;
        offs += c->lsave_sz;
        dbg_chk_lpt_sz(c, 1, c->lsave_sz);
    }

    if (offs + c->ltab_sz <= c->leb_size) {
        done_ltab = 1;
        c->ltab_lnum = lnum;
        c->ltab_offs = offs;
        offs += c->ltab_sz;
        dbg_chk_lpt_sz(c, 1, c->ltab_sz);
    }

    do {
        if (cnode->level) {
            len = c->nnode_sz;
            c->dirty_nn_cnt -= 1;
        } else {
            len = c->pnode_sz;
            c->dirty_pn_cnt -= 1;
        }
        while (offs + len > c->leb_size) {
            alen = ALIGN(offs, c->min_io_size);
            upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
            dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
            err = alloc_lpt_leb(c, &lnum);
            if (err)
                goto no_space;
            offs = 0;
            ubifs_assert(lnum >= c->lpt_first &&
                     lnum <= c->lpt_last);
            /* Try to place lsave and ltab nicely */
            if (!done_lsave) {
                done_lsave = 1;
                c->lsave_lnum = lnum;
                c->lsave_offs = offs;
                offs += c->lsave_sz;
                dbg_chk_lpt_sz(c, 1, c->lsave_sz);
                continue;
            }
            if (!done_ltab) {
                done_ltab = 1;
                c->ltab_lnum = lnum;
                c->ltab_offs = offs;
                offs += c->ltab_sz;
                dbg_chk_lpt_sz(c, 1, c->ltab_sz);
                continue;
            }
            break;
        }
        if (cnode->parent) {
            cnode->parent->nbranch[cnode->iip].lnum = lnum;
            cnode->parent->nbranch[cnode->iip].offs = offs;
        } else {
            c->lpt_lnum = lnum;
            c->lpt_offs = offs;
        }
        offs += len;
        dbg_chk_lpt_sz(c, 1, len);
        cnode = cnode->cnext;
    } while (cnode && cnode != c->lpt_cnext);

    /* Make sure to place LPT's save table */
    if (!done_lsave) {
        if (offs + c->lsave_sz > c->leb_size) {
            alen = ALIGN(offs, c->min_io_size);
            upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
            dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
            err = alloc_lpt_leb(c, &lnum);
            if (err)
                goto no_space;
            offs = 0;
            ubifs_assert(lnum >= c->lpt_first &&
                     lnum <= c->lpt_last);
        }
        done_lsave = 1;
        c->lsave_lnum = lnum;
        c->lsave_offs = offs;
        offs += c->lsave_sz;
        dbg_chk_lpt_sz(c, 1, c->lsave_sz);
    }

    /* Make sure to place LPT's own lprops table */
    if (!done_ltab) {
        if (offs + c->ltab_sz > c->leb_size) {
            alen = ALIGN(offs, c->min_io_size);
            upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
            dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
            err = alloc_lpt_leb(c, &lnum);
            if (err)
                goto no_space;
            offs = 0;
            ubifs_assert(lnum >= c->lpt_first &&
                     lnum <= c->lpt_last);
        }
        done_ltab = 1;
        c->ltab_lnum = lnum;
        c->ltab_offs = offs;
        offs += c->ltab_sz;
        dbg_chk_lpt_sz(c, 1, c->ltab_sz);
    }

    alen = ALIGN(offs, c->min_io_size);
    upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
    dbg_chk_lpt_sz(c, 4, alen - offs);
    err = dbg_chk_lpt_sz(c, 3, alen);
    if (err)
        return err;
    return 0;

no_space:
    ubifs_err("LPT out of space at LEB %d:%d needing %d, done_ltab %d, done_lsave %d",
          lnum, offs, len, done_ltab, done_lsave);
    ubifs_dump_lpt_info(c);
    ubifs_dump_lpt_lebs(c);
    dump_stack();
    return err;
}

static int realloc_lpt_leb(struct ubifs_info *c, int *lnum)
{
    int i, n;

    n = *lnum - c->lpt_first + 1;
    for (i = n; i < c->lpt_lebs; i++)
        if (c->ltab[i].cmt) {
            c->ltab[i].cmt = 0;
            *lnum = i + c->lpt_first;
            return 0;
        }

    for (i = 0; i < n; i++)
        if (c->ltab[i].cmt) {
            c->ltab[i].cmt = 0;
            *lnum = i + c->lpt_first;
            return 0;
        }
    return -ENOSPC;
}

static int write_cnodes(struct ubifs_info *c)
{
    int lnum, offs, len, from, err, wlen, alen, done_ltab, done_lsave;
    struct ubifs_cnode *cnode;
    void *buf = c->lpt_buf;

    cnode = c->lpt_cnext;
    if (!cnode)
        return 0;
    lnum = c->nhead_lnum;
    offs = c->nhead_offs;
    from = offs;
    /* Ensure empty LEB is unmapped */
    if (offs == 0) {
        err = ubifs_leb_unmap(c, lnum);
        if (err)
            return err;
    }
    /* Try to place lsave and ltab nicely */
    done_lsave = !c->big_lpt;
    done_ltab = 0;
    if (!done_lsave && offs + c->lsave_sz <= c->leb_size) {
        done_lsave = 1;
        ubifs_pack_lsave(c, buf + offs, c->lsave);
        offs += c->lsave_sz;
        dbg_chk_lpt_sz(c, 1, c->lsave_sz);
    }

    if (offs + c->ltab_sz <= c->leb_size) {
        done_ltab = 1;
        ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
        offs += c->ltab_sz;
        dbg_chk_lpt_sz(c, 1, c->ltab_sz);
    }

    /* Loop for each cnode */
    do {
        if (cnode->level)
            len = c->nnode_sz;
        else
            len = c->pnode_sz;
        while (offs + len > c->leb_size) {
            wlen = offs - from;
            if (wlen) {
                alen = ALIGN(wlen, c->min_io_size);
                memset(buf + offs, 0xff, alen - wlen);
                err = ubifs_leb_write(c, lnum, buf + from, from,
                               alen);
                if (err)
                    return err;
            }
            dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
            err = realloc_lpt_leb(c, &lnum);
            if (err)
                goto no_space;
            offs = from = 0;
            ubifs_assert(lnum >= c->lpt_first &&
                     lnum <= c->lpt_last);
            err = ubifs_leb_unmap(c, lnum);
            if (err)
                return err;
            /* Try to place lsave and ltab nicely */
            if (!done_lsave) {
                done_lsave = 1;
                ubifs_pack_lsave(c, buf + offs, c->lsave);
                offs += c->lsave_sz;
                dbg_chk_lpt_sz(c, 1, c->lsave_sz);
                continue;
            }
            if (!done_ltab) {
                done_ltab = 1;
                ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
                offs += c->ltab_sz;
                dbg_chk_lpt_sz(c, 1, c->ltab_sz);
                continue;
            }
            break;
        }
        if (cnode->level)
            ubifs_pack_nnode(c, buf + offs,
                     (struct ubifs_nnode *)cnode);
        else
            ubifs_pack_pnode(c, buf + offs,
                     (struct ubifs_pnode *)cnode);
        /*
         * The reason for the barriers is the same as in case of TNC.
         * See comment in 'write_index()'. 'dirty_cow_nnode()' and
         * 'dirty_cow_pnode()' are the functions for which this is
         * important.
         */
        clear_bit(DIRTY_CNODE, &cnode->flags);
        smp_mb__before_clear_bit();
        clear_bit(COW_CNODE, &cnode->flags);
        smp_mb__after_clear_bit();
        offs += len;
        dbg_chk_lpt_sz(c, 1, len);
        cnode = cnode->cnext;
    } while (cnode && cnode != c->lpt_cnext);

    /* Make sure to place LPT's save table */
    if (!done_lsave) {
        if (offs + c->lsave_sz > c->leb_size) {
            wlen = offs - from;
            alen = ALIGN(wlen, c->min_io_size);
            memset(buf + offs, 0xff, alen - wlen);
            err = ubifs_leb_write(c, lnum, buf + from, from, alen);
            if (err)
                return err;
            dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
            err = realloc_lpt_leb(c, &lnum);
            if (err)
                goto no_space;
            offs = from = 0;
            ubifs_assert(lnum >= c->lpt_first &&
                     lnum <= c->lpt_last);
            err = ubifs_leb_unmap(c, lnum);
            if (err)
                return err;
        }
        done_lsave = 1;
        ubifs_pack_lsave(c, buf + offs, c->lsave);
        offs += c->lsave_sz;
        dbg_chk_lpt_sz(c, 1, c->lsave_sz);
    }

    /* Make sure to place LPT's own lprops table */
    if (!done_ltab) {
        if (offs + c->ltab_sz > c->leb_size) {
            wlen = offs - from;
            alen = ALIGN(wlen, c->min_io_size);
            memset(buf + offs, 0xff, alen - wlen);
            err = ubifs_leb_write(c, lnum, buf + from, from, alen);
            if (err)
                return err;
            dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
            err = realloc_lpt_leb(c, &lnum);
            if (err)
                goto no_space;
            offs = from = 0;
            ubifs_assert(lnum >= c->lpt_first &&
                     lnum <= c->lpt_last);
            err = ubifs_leb_unmap(c, lnum);
            if (err)
                return err;
        }
        done_ltab = 1;
        ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
        offs += c->ltab_sz;
        dbg_chk_lpt_sz(c, 1, c->ltab_sz);
    }

    /* Write remaining data in buffer */
    wlen = offs - from;
    alen = ALIGN(wlen, c->min_io_size);
    memset(buf + offs, 0xff, alen - wlen);
    err = ubifs_leb_write(c, lnum, buf + from, from, alen);
    if (err)
        return err;

    dbg_chk_lpt_sz(c, 4, alen - wlen);
    err = dbg_chk_lpt_sz(c, 3, ALIGN(offs, c->min_io_size));
    if (err)
        return err;

    c->nhead_lnum = lnum;
    c->nhead_offs = ALIGN(offs, c->min_io_size);

    dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
    dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
    dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
    if (c->big_lpt)
        dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);

    return 0;

no_space:
    ubifs_err("LPT out of space mismatch at LEB %d:%d needing %d, done_ltab %d, done_lsave %d",
          lnum, offs, len, done_ltab, done_lsave);
    ubifs_dump_lpt_info(c);
    ubifs_dump_lpt_lebs(c);
    dump_stack();
    return err;
}

static struct ubifs_pnode *next_pnode_to_dirty(struct ubifs_info *c,
                           struct ubifs_pnode *pnode)
{
    struct ubifs_nnode *nnode;
    int iip;

    /* Try to go right */
    nnode = pnode->parent;
    for (iip = pnode->iip + 1; iip < UBIFS_LPT_FANOUT; iip++) {
        if (nnode->nbranch[iip].lnum)
            return ubifs_get_pnode(c, nnode, iip);
    }

    /* Go up while can't go right */
    do {
        iip = nnode->iip + 1;
        nnode = nnode->parent;
        if (!nnode)
            return NULL;
        for (; iip < UBIFS_LPT_FANOUT; iip++) {
            if (nnode->nbranch[iip].lnum)
                break;
        }
    } while (iip >= UBIFS_LPT_FANOUT);

    /* Go right */
    nnode = ubifs_get_nnode(c, nnode, iip);
    if (IS_ERR(nnode))
        return (void *)nnode;

    /* Go down to level 1 */
    while (nnode->level > 1) {
        for (iip = 0; iip < UBIFS_LPT_FANOUT; iip++) {
            if (nnode->nbranch[iip].lnum)
                break;
        }
        if (iip >= UBIFS_LPT_FANOUT) {
            /*
             * Should not happen, but we need to keep going
             * if it does.
             */
            iip = 0;
        }
        nnode = ubifs_get_nnode(c, nnode, iip);
        if (IS_ERR(nnode))
            return (void *)nnode;
    }

    for (iip = 0; iip < UBIFS_LPT_FANOUT; iip++)
        if (nnode->nbranch[iip].lnum)
            break;
    if (iip >= UBIFS_LPT_FANOUT)
        /* Should not happen, but we need to keep going if it does */
        iip = 0;
    return ubifs_get_pnode(c, nnode, iip);
}

static struct ubifs_pnode *pnode_lookup(struct ubifs_info *c, int i)
{
    int err, h, iip, shft;
    struct ubifs_nnode *nnode;

    if (!c->nroot) {
        err = ubifs_read_nnode(c, NULL, 0);
        if (err)
            return ERR_PTR(err);
    }
    i <<= UBIFS_LPT_FANOUT_SHIFT;
    nnode = c->nroot;
    shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
    for (h = 1; h < c->lpt_hght; h++) {
        iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
        shft -= UBIFS_LPT_FANOUT_SHIFT;
        nnode = ubifs_get_nnode(c, nnode, iip);
        if (IS_ERR(nnode))
            return ERR_CAST(nnode);
    }
    iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
    return ubifs_get_pnode(c, nnode, iip);
}

static void add_pnode_dirt(struct ubifs_info *c, struct ubifs_pnode *pnode)
{
    ubifs_add_lpt_dirt(c, pnode->parent->nbranch[pnode->iip].lnum,
               c->pnode_sz);
}

static void do_make_pnode_dirty(struct ubifs_info *c, struct ubifs_pnode *pnode)
{
    /* Assumes cnext list is empty i.e. not called during commit */
    if (!test_and_set_bit(DIRTY_CNODE, &pnode->flags)) {
        struct ubifs_nnode *nnode;

        c->dirty_pn_cnt += 1;
        add_pnode_dirt(c, pnode);
        /* Mark parent and ancestors dirty too */
        nnode = pnode->parent;
        while (nnode) {
            if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
                c->dirty_nn_cnt += 1;
                ubifs_add_nnode_dirt(c, nnode);
                nnode = nnode->parent;
            } else
                break;
        }
    }
}

static int make_tree_dirty(struct ubifs_info *c)
{
    struct ubifs_pnode *pnode;

    pnode = pnode_lookup(c, 0);
    if (IS_ERR(pnode))
        return PTR_ERR(pnode);

    while (pnode) {
        do_make_pnode_dirty(c, pnode);
        pnode = next_pnode_to_dirty(c, pnode);
        if (IS_ERR(pnode))
            return PTR_ERR(pnode);
    }
    return 0;
}

static int need_write_all(struct ubifs_info *c)
{
    long long free = 0;
    int i;

    for (i = 0; i < c->lpt_lebs; i++) {
        if (i + c->lpt_first == c->nhead_lnum)
            free += c->leb_size - c->nhead_offs;
        else if (c->ltab[i].free == c->leb_size)
            free += c->leb_size;
        else if (c->ltab[i].free + c->ltab[i].dirty == c->leb_size)
            free += c->leb_size;
    }
    /* Less than twice the size left */
    if (free <= c->lpt_sz * 2)
        return 1;
    return 0;
}

static void lpt_tgc_start(struct ubifs_info *c)
{
    int i;

    for (i = 0; i < c->lpt_lebs; i++) {
        if (i + c->lpt_first == c->nhead_lnum)
            continue;
        if (c->ltab[i].dirty > 0 &&
            c->ltab[i].free + c->ltab[i].dirty == c->leb_size) {
            c->ltab[i].tgc = 1;
            c->ltab[i].free = c->leb_size;
            c->ltab[i].dirty = 0;
            dbg_lp("LEB %d", i + c->lpt_first);
        }
    }
}

static int lpt_tgc_end(struct ubifs_info *c)
{
    int i, err;

    for (i = 0; i < c->lpt_lebs; i++)
        if (c->ltab[i].tgc) {
            err = ubifs_leb_unmap(c, i + c->lpt_first);
            if (err)
                return err;
            c->ltab[i].tgc = 0;
            dbg_lp("LEB %d", i + c->lpt_first);
        }
    return 0;
}

static void populate_lsave(struct ubifs_info *c)
{
    struct ubifs_lprops *lprops;
    struct ubifs_lpt_heap *heap;
    int i, cnt = 0;

    ubifs_assert(c->big_lpt);
    if (!(c->lpt_drty_flgs & LSAVE_DIRTY)) {
        c->lpt_drty_flgs |= LSAVE_DIRTY;
        ubifs_add_lpt_dirt(c, c->lsave_lnum, c->lsave_sz);
    }

    if (dbg_populate_lsave(c))
        return;

    list_for_each_entry(lprops, &c->empty_list, list) {
        c->lsave[cnt++] = lprops->lnum;
        if (cnt >= c->lsave_cnt)
            return;
    }
    list_for_each_entry(lprops, &c->freeable_list, list) {
        c->lsave[cnt++] = lprops->lnum;
        if (cnt >= c->lsave_cnt)
            return;
    }
    list_for_each_entry(lprops, &c->frdi_idx_list, list) {
        c->lsave[cnt++] = lprops->lnum;
        if (cnt >= c->lsave_cnt)
            return;
    }
    heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
    for (i = 0; i < heap->cnt; i++) {
        c->lsave[cnt++] = heap->arr[i]->lnum;
        if (cnt >= c->lsave_cnt)
            return;
    }
    heap = &c->lpt_heap[LPROPS_DIRTY - 1];
    for (i = 0; i < heap->cnt; i++) {
        c->lsave[cnt++] = heap->arr[i]->lnum;
        if (cnt >= c->lsave_cnt)
            return;
    }
    heap = &c->lpt_heap[LPROPS_FREE - 1];
    for (i = 0; i < heap->cnt; i++) {
        c->lsave[cnt++] = heap->arr[i]->lnum;
        if (cnt >= c->lsave_cnt)
            return;
    }
    /* Fill it up completely */
    while (cnt < c->lsave_cnt)
        c->lsave[cnt++] = c->main_first;
}

static struct ubifs_nnode *nnode_lookup(struct ubifs_info *c, int i)
{
    int err, iip;
    struct ubifs_nnode *nnode;

    if (!c->nroot) {
        err = ubifs_read_nnode(c, NULL, 0);
        if (err)
            return ERR_PTR(err);
    }
    nnode = c->nroot;
    while (1) {
        iip = i & (UBIFS_LPT_FANOUT - 1);
        i >>= UBIFS_LPT_FANOUT_SHIFT;
        if (!i)
            break;
        nnode = ubifs_get_nnode(c, nnode, iip);
        if (IS_ERR(nnode))
            return nnode;
    }
    return nnode;
}

static int make_nnode_dirty(struct ubifs_info *c, int node_num, int lnum,
                int offs)
{
    struct ubifs_nnode *nnode;

    nnode = nnode_lookup(c, node_num);
    if (IS_ERR(nnode))
        return PTR_ERR(nnode);
    if (nnode->parent) {
        struct ubifs_nbranch *branch;

        branch = &nnode->parent->nbranch[nnode->iip];
        if (branch->lnum != lnum || branch->offs != offs)
            return 0; /* nnode is obsolete */
    } else if (c->lpt_lnum != lnum || c->lpt_offs != offs)
            return 0; /* nnode is obsolete */
    /* Assumes cnext list is empty i.e. not called during commit */
    if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
        c->dirty_nn_cnt += 1;
        ubifs_add_nnode_dirt(c, nnode);
        /* Mark parent and ancestors dirty too */
        nnode = nnode->parent;
        while (nnode) {
            if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
                c->dirty_nn_cnt += 1;
                ubifs_add_nnode_dirt(c, nnode);
                nnode = nnode->parent;
            } else
                break;
        }
    }
    return 0;
}

static int make_pnode_dirty(struct ubifs_info *c, int node_num, int lnum,
                int offs)
{
    struct ubifs_pnode *pnode;
    struct ubifs_nbranch *branch;

    pnode = pnode_lookup(c, node_num);
    if (IS_ERR(pnode))
        return PTR_ERR(pnode);
    branch = &pnode->parent->nbranch[pnode->iip];
    if (branch->lnum != lnum || branch->offs != offs)
        return 0;
    do_make_pnode_dirty(c, pnode);
    return 0;
}

static int make_ltab_dirty(struct ubifs_info *c, int lnum, int offs)
{
    if (lnum != c->ltab_lnum || offs != c->ltab_offs)
        return 0; /* This ltab node is obsolete */
    if (!(c->lpt_drty_flgs & LTAB_DIRTY)) {
        c->lpt_drty_flgs |= LTAB_DIRTY;
        ubifs_add_lpt_dirt(c, c->ltab_lnum, c->ltab_sz);
    }
    return 0;
}

static int make_lsave_dirty(struct ubifs_info *c, int lnum, int offs)
{
    if (lnum != c->lsave_lnum || offs != c->lsave_offs)
        return 0; /* This lsave node is obsolete */
    if (!(c->lpt_drty_flgs & LSAVE_DIRTY)) {
        c->lpt_drty_flgs |= LSAVE_DIRTY;
        ubifs_add_lpt_dirt(c, c->lsave_lnum, c->lsave_sz);
    }
    return 0;
}

static int make_node_dirty(struct ubifs_info *c, int node_type, int node_num,
               int lnum, int offs)
{
    switch (node_type) {
    case UBIFS_LPT_NNODE:
        return make_nnode_dirty(c, node_num, lnum, offs);
    case UBIFS_LPT_PNODE:
        return make_pnode_dirty(c, node_num, lnum, offs);
    case UBIFS_LPT_LTAB:
        return make_ltab_dirty(c, lnum, offs);
    case UBIFS_LPT_LSAVE:
        return make_lsave_dirty(c, lnum, offs);
    }
    return -EINVAL;
}

static int get_lpt_node_len(const struct ubifs_info *c, int node_type)
{
    switch (node_type) {
    case UBIFS_LPT_NNODE:
        return c->nnode_sz;
    case UBIFS_LPT_PNODE:
        return c->pnode_sz;
    case UBIFS_LPT_LTAB:
        return c->ltab_sz;
    case UBIFS_LPT_LSAVE:
        return c->lsave_sz;
    }
    return 0;
}

static int get_pad_len(const struct ubifs_info *c, uint8_t *buf, int len)
{
    int offs, pad_len;

    if (c->min_io_size == 1)
        return 0;
    offs = c->leb_size - len;
    pad_len = ALIGN(offs, c->min_io_size) - offs;
    return pad_len;
}

static int get_lpt_node_type(const struct ubifs_info *c, uint8_t *buf,
                 int *node_num)
{
    uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
    int pos = 0, node_type;

    node_type = ubifs_unpack_bits(&addr, &pos, UBIFS_LPT_TYPE_BITS);
    *node_num = ubifs_unpack_bits(&addr, &pos, c->pcnt_bits);
    return node_type;
}

static int is_a_node(const struct ubifs_info *c, uint8_t *buf, int len)
{
    uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
    int pos = 0, node_type, node_len;
    uint16_t crc, calc_crc;

    if (len < UBIFS_LPT_CRC_BYTES + (UBIFS_LPT_TYPE_BITS + 7) / 8)
        return 0;
    node_type = ubifs_unpack_bits(&addr, &pos, UBIFS_LPT_TYPE_BITS);
    if (node_type == UBIFS_LPT_NOT_A_NODE)
        return 0;
    node_len = get_lpt_node_len(c, node_type);
    if (!node_len || node_len > len)
        return 0;
    pos = 0;
    addr = buf;
    crc = ubifs_unpack_bits(&addr, &pos, UBIFS_LPT_CRC_BITS);
    calc_crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
             node_len - UBIFS_LPT_CRC_BYTES);
    if (crc != calc_crc)
        return 0;
    return 1;
}

static int lpt_gc_lnum(struct ubifs_info *c, int lnum)
{
    int err, len = c->leb_size, node_type, node_num, node_len, offs;
    void *buf = c->lpt_buf;

    dbg_lp("LEB %d", lnum);

    err = ubifs_leb_read(c, lnum, buf, 0, c->leb_size, 1);
    if (err)
        return err;

    while (1) {
        if (!is_a_node(c, buf, len)) {
            int pad_len;

            pad_len = get_pad_len(c, buf, len);
            if (pad_len) {
                buf += pad_len;
                len -= pad_len;
                continue;
            }
            return 0;
        }
        node_type = get_lpt_node_type(c, buf, &node_num);
        node_len = get_lpt_node_len(c, node_type);
        offs = c->leb_size - len;
        ubifs_assert(node_len != 0);
        mutex_lock(&c->lp_mutex);
        err = make_node_dirty(c, node_type, node_num, lnum, offs);
        mutex_unlock(&c->lp_mutex);
        if (err)
            return err;
        buf += node_len;
        len -= node_len;
    }
    return 0;
}

static int lpt_gc(struct ubifs_info *c)
{
    int i, lnum = -1, dirty = 0;

    mutex_lock(&c->lp_mutex);
    for (i = 0; i < c->lpt_lebs; i++) {
        ubifs_assert(!c->ltab[i].tgc);
        if (i + c->lpt_first == c->nhead_lnum ||
            c->ltab[i].free + c->ltab[i].dirty == c->leb_size)
            continue;
        if (c->ltab[i].dirty > dirty) {
            dirty = c->ltab[i].dirty;
            lnum = i + c->lpt_first;
        }
    }
    mutex_unlock(&c->lp_mutex);
    if (lnum == -1)
        return -ENOSPC;
    return lpt_gc_lnum(c, lnum);
}

int ubifs_lpt_start_commit(struct ubifs_info *c)
{
    int err, cnt;

    dbg_lp("");

    mutex_lock(&c->lp_mutex);
    err = dbg_chk_lpt_free_spc(c);
    if (err)
        goto out;
    err = dbg_check_ltab(c);
    if (err)
        goto out;

    if (c->check_lpt_free) {
        /*
         * We ensure there is enough free space in
         * ubifs_lpt_post_commit() by marking nodes dirty. That
         * information is lost when we unmount, so we also need
         * to check free space once after mounting also.
         */
        c->check_lpt_free = 0;
        while (need_write_all(c)) {
            mutex_unlock(&c->lp_mutex);
            err = lpt_gc(c);
            if (err)
                return err;
            mutex_lock(&c->lp_mutex);
        }
    }

    lpt_tgc_start(c);

    if (!c->dirty_pn_cnt) {
        dbg_cmt("no cnodes to commit");
        err = 0;
        goto out;
    }

    if (!c->big_lpt && need_write_all(c)) {
        /* If needed, write everything */
        err = make_tree_dirty(c);
        if (err)
            goto out;
        lpt_tgc_start(c);
    }

    if (c->big_lpt)
        populate_lsave(c);

    cnt = get_cnodes_to_commit(c);
    ubifs_assert(cnt != 0);

    err = layout_cnodes(c);
    if (err)
        goto out;

    /* Copy the LPT's own lprops for end commit to write */
    memcpy(c->ltab_cmt, c->ltab,
           sizeof(struct ubifs_lpt_lprops) * c->lpt_lebs);
    c->lpt_drty_flgs &= ~(LTAB_DIRTY | LSAVE_DIRTY);

out:
    mutex_unlock(&c->lp_mutex);
    return err;
}

static void free_obsolete_cnodes(struct ubifs_info *c)
{
    struct ubifs_cnode *cnode, *cnext;

    cnext = c->lpt_cnext;
    if (!cnext)
        return;
    do {
        cnode = cnext;
        cnext = cnode->cnext;
        if (test_bit(OBSOLETE_CNODE, &cnode->flags))
            kfree(cnode);
        else
            cnode->cnext = NULL;
    } while (cnext != c->lpt_cnext);
    c->lpt_cnext = NULL;
}

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

    dbg_lp("");

    if (!c->lpt_cnext)
        return 0;

    err = write_cnodes(c);
    if (err)
        return err;

    mutex_lock(&c->lp_mutex);
    free_obsolete_cnodes(c);
    mutex_unlock(&c->lp_mutex);

    return 0;
}

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

    mutex_lock(&c->lp_mutex);
    err = lpt_tgc_end(c);
    if (err)
        goto out;
    if (c->big_lpt)
        while (need_write_all(c)) {
            mutex_unlock(&c->lp_mutex);
            err = lpt_gc(c);
            if (err)
                return err;
            mutex_lock(&c->lp_mutex);
        }
out:
    mutex_unlock(&c->lp_mutex);
    return err;
}

static struct ubifs_nnode *first_nnode(struct ubifs_info *c, int *hght)
{
    struct ubifs_nnode *nnode;
    int h, i, found;

    nnode = c->nroot;
    *hght = 0;
    if (!nnode)
        return NULL;
    for (h = 1; h < c->lpt_hght; h++) {
        found = 0;
        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
            if (nnode->nbranch[i].nnode) {
                found = 1;
                nnode = nnode->nbranch[i].nnode;
                *hght = h;
                break;
            }
        }
        if (!found)
            break;
    }
    return nnode;
}

static struct ubifs_nnode *next_nnode(struct ubifs_info *c,
                      struct ubifs_nnode *nnode, int *hght)
{
    struct ubifs_nnode *parent;
    int iip, h, i, found;

    parent = nnode->parent;
    if (!parent)
        return NULL;
    if (nnode->iip == UBIFS_LPT_FANOUT - 1) {
        *hght -= 1;
        return parent;
    }
    for (iip = nnode->iip + 1; iip < UBIFS_LPT_FANOUT; iip++) {
        nnode = parent->nbranch[iip].nnode;
        if (nnode)
            break;
    }
    if (!nnode) {
        *hght -= 1;
        return parent;
    }
    for (h = *hght + 1; h < c->lpt_hght; h++) {
        found = 0;
        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
            if (nnode->nbranch[i].nnode) {
                found = 1;
                nnode = nnode->nbranch[i].nnode;
                *hght = h;
                break;
            }
        }
        if (!found)
            break;
    }
    return nnode;
}

void ubifs_lpt_free(struct ubifs_info *c, int wr_only)
{
    struct ubifs_nnode *nnode;
    int i, hght;

    /* Free write-only things first */

    free_obsolete_cnodes(c); /* Leftover from a failed commit */

    vfree(c->ltab_cmt);
    c->ltab_cmt = NULL;
    vfree(c->lpt_buf);
    c->lpt_buf = NULL;
    kfree(c->lsave);
    c->lsave = NULL;

    if (wr_only)
        return;

    /* Now free the rest */

    nnode = first_nnode(c, &hght);
    while (nnode) {
        for (i = 0; i < UBIFS_LPT_FANOUT; i++)
            kfree(nnode->nbranch[i].nnode);
        nnode = next_nnode(c, nnode, &hght);
    }
    for (i = 0; i < LPROPS_HEAP_CNT; i++)
        kfree(c->lpt_heap[i].arr);
    kfree(c->dirty_idx.arr);
    kfree(c->nroot);
    vfree(c->ltab);
    kfree(c->lpt_nod_buf);
}

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

static int dbg_is_all_ff(uint8_t *buf, int len)
{
    int i;

    for (i = 0; i < len; i++)
        if (buf[i] != 0xff)
            return 0;
    return 1;
}

static int dbg_is_nnode_dirty(struct ubifs_info *c, int lnum, int offs)
{
    struct ubifs_nnode *nnode;
    int hght;

    /* Entire tree is in memory so first_nnode / next_nnode are OK */
    nnode = first_nnode(c, &hght);
    for (; nnode; nnode = next_nnode(c, nnode, &hght)) {
        struct ubifs_nbranch *branch;

        cond_resched();
        if (nnode->parent) {
            branch = &nnode->parent->nbranch[nnode->iip];
            if (branch->lnum != lnum || branch->offs != offs)
                continue;
            if (test_bit(DIRTY_CNODE, &nnode->flags))
                return 1;
            return 0;
        } else {
            if (c->lpt_lnum != lnum || c->lpt_offs != offs)
                continue;
            if (test_bit(DIRTY_CNODE, &nnode->flags))
                return 1;
            return 0;
        }
    }
    return 1;
}

static int dbg_is_pnode_dirty(struct ubifs_info *c, int lnum, int offs)
{
    int i, cnt;

    cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
    for (i = 0; i < cnt; i++) {
        struct ubifs_pnode *pnode;
        struct ubifs_nbranch *branch;

        cond_resched();
        pnode = pnode_lookup(c, i);
        if (IS_ERR(pnode))
            return PTR_ERR(pnode);
        branch = &pnode->parent->nbranch[pnode->iip];
        if (branch->lnum != lnum || branch->offs != offs)
            continue;
        if (test_bit(DIRTY_CNODE, &pnode->flags))
            return 1;
        return 0;
    }
    return 1;
}

static int dbg_is_ltab_dirty(struct ubifs_info *c, int lnum, int offs)
{
    if (lnum != c->ltab_lnum || offs != c->ltab_offs)
        return 1;
    return (c->lpt_drty_flgs & LTAB_DIRTY) != 0;
}

static int dbg_is_lsave_dirty(struct ubifs_info *c, int lnum, int offs)
{
    if (lnum != c->lsave_lnum || offs != c->lsave_offs)
        return 1;
    return (c->lpt_drty_flgs & LSAVE_DIRTY) != 0;
}

static int dbg_is_node_dirty(struct ubifs_info *c, int node_type, int lnum,
                 int offs)
{
    switch (node_type) {
    case UBIFS_LPT_NNODE:
        return dbg_is_nnode_dirty(c, lnum, offs);
    case UBIFS_LPT_PNODE:
        return dbg_is_pnode_dirty(c, lnum, offs);
    case UBIFS_LPT_LTAB:
        return dbg_is_ltab_dirty(c, lnum, offs);
    case UBIFS_LPT_LSAVE:
        return dbg_is_lsave_dirty(c, lnum, offs);
    }
    return 1;
}

static int dbg_check_ltab_lnum(struct ubifs_info *c, int lnum)
{
    int err, len = c->leb_size, dirty = 0, node_type, node_num, node_len;
    int ret;
    void *buf, *p;

    if (!dbg_is_chk_lprops(c))
        return 0;

    buf = p = __vmalloc(c->leb_size, GFP_NOFS, PAGE_KERNEL);
    if (!buf) {
        ubifs_err("cannot allocate memory for ltab checking");
        return 0;
    }

    dbg_lp("LEB %d", lnum);

    err = ubifs_leb_read(c, lnum, buf, 0, c->leb_size, 1);
    if (err)
        goto out;

    while (1) {
        if (!is_a_node(c, p, len)) {
            int i, pad_len;

            pad_len = get_pad_len(c, p, len);
            if (pad_len) {
                p += pad_len;
                len -= pad_len;
                dirty += pad_len;
                continue;
            }
            if (!dbg_is_all_ff(p, len)) {
                ubifs_err("invalid empty space in LEB %d at %d",
                      lnum, c->leb_size - len);
                err = -EINVAL;
            }
            i = lnum - c->lpt_first;
            if (len != c->ltab[i].free) {
                ubifs_err("invalid free space in LEB %d (free %d, expected %d)",
                      lnum, len, c->ltab[i].free);
                err = -EINVAL;
            }
            if (dirty != c->ltab[i].dirty) {
                ubifs_err("invalid dirty space in LEB %d (dirty %d, expected %d)",
                      lnum, dirty, c->ltab[i].dirty);
                err = -EINVAL;
            }
            goto out;
        }
        node_type = get_lpt_node_type(c, p, &node_num);
        node_len = get_lpt_node_len(c, node_type);
        ret = dbg_is_node_dirty(c, node_type, lnum, c->leb_size - len);
        if (ret == 1)
            dirty += node_len;
        p += node_len;
        len -= node_len;
    }

    err = 0;
out:
    vfree(buf);
    return err;
}

int dbg_check_ltab(struct ubifs_info *c)
{
    int lnum, err, i, cnt;

    if (!dbg_is_chk_lprops(c))
        return 0;

    /* Bring the entire tree into memory */
    cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
    for (i = 0; i < cnt; i++) {
        struct ubifs_pnode *pnode;

        pnode = pnode_lookup(c, i);
        if (IS_ERR(pnode))
            return PTR_ERR(pnode);
        cond_resched();
    }

    /* Check nodes */
    err = dbg_check_lpt_nodes(c, (struct ubifs_cnode *)c->nroot, 0, 0);
    if (err)
        return err;

    /* Check each LEB */
    for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
        err = dbg_check_ltab_lnum(c, lnum);
        if (err) {
            ubifs_err("failed at LEB %d", lnum);
            return err;
        }
    }

    dbg_lp("succeeded");
    return 0;
}

int dbg_chk_lpt_free_spc(struct ubifs_info *c)
{
    long long free = 0;
    int i;

    if (!dbg_is_chk_lprops(c))
        return 0;

    for (i = 0; i < c->lpt_lebs; i++) {
        if (c->ltab[i].tgc || c->ltab[i].cmt)
            continue;
        if (i + c->lpt_first == c->nhead_lnum)
            free += c->leb_size - c->nhead_offs;
        else if (c->ltab[i].free == c->leb_size)
            free += c->leb_size;
    }
    if (free < c->lpt_sz) {
        ubifs_err("LPT space error: free %lld lpt_sz %lld",
              free, c->lpt_sz);
        ubifs_dump_lpt_info(c);
        ubifs_dump_lpt_lebs(c);
        dump_stack();
        return -EINVAL;
    }
    return 0;
}

int dbg_chk_lpt_sz(struct ubifs_info *c, int action, int len)
{
    struct ubifs_debug_info *d = c->dbg;
    long long chk_lpt_sz, lpt_sz;
    int err = 0;

    if (!dbg_is_chk_lprops(c))
        return 0;

    switch (action) {
    case 0:
        d->chk_lpt_sz = 0;
        d->chk_lpt_sz2 = 0;
        d->chk_lpt_lebs = 0;
        d->chk_lpt_wastage = 0;
        if (c->dirty_pn_cnt > c->pnode_cnt) {
            ubifs_err("dirty pnodes %d exceed max %d",
                  c->dirty_pn_cnt, c->pnode_cnt);
            err = -EINVAL;
        }
        if (c->dirty_nn_cnt > c->nnode_cnt) {
            ubifs_err("dirty nnodes %d exceed max %d",
                  c->dirty_nn_cnt, c->nnode_cnt);
            err = -EINVAL;
        }
        return err;
    case 1:
        d->chk_lpt_sz += len;
        return 0;
    case 2:
        d->chk_lpt_sz += len;
        d->chk_lpt_wastage += len;
        d->chk_lpt_lebs += 1;
        return 0;
    case 3:
        chk_lpt_sz = c->leb_size;
        chk_lpt_sz *= d->chk_lpt_lebs;
        chk_lpt_sz += len - c->nhead_offs;
        if (d->chk_lpt_sz != chk_lpt_sz) {
            ubifs_err("LPT wrote %lld but space used was %lld",
                  d->chk_lpt_sz, chk_lpt_sz);
            err = -EINVAL;
        }
        if (d->chk_lpt_sz > c->lpt_sz) {
            ubifs_err("LPT wrote %lld but lpt_sz is %lld",
                  d->chk_lpt_sz, c->lpt_sz);
            err = -EINVAL;
        }
        if (d->chk_lpt_sz2 && d->chk_lpt_sz != d->chk_lpt_sz2) {
            ubifs_err("LPT layout size %lld but wrote %lld",
                  d->chk_lpt_sz, d->chk_lpt_sz2);
            err = -EINVAL;
        }
        if (d->chk_lpt_sz2 && d->new_nhead_offs != len) {
            ubifs_err("LPT new nhead offs: expected %d was %d",
                  d->new_nhead_offs, len);
            err = -EINVAL;
        }
        lpt_sz = (long long)c->pnode_cnt * c->pnode_sz;
        lpt_sz += (long long)c->nnode_cnt * c->nnode_sz;
        lpt_sz += c->ltab_sz;
        if (c->big_lpt)
            lpt_sz += c->lsave_sz;
        if (d->chk_lpt_sz - d->chk_lpt_wastage > lpt_sz) {
            ubifs_err("LPT chk_lpt_sz %lld + waste %lld exceeds %lld",
                  d->chk_lpt_sz, d->chk_lpt_wastage, lpt_sz);
            err = -EINVAL;
        }
        if (err) {
            ubifs_dump_lpt_info(c);
            ubifs_dump_lpt_lebs(c);
            dump_stack();
        }
        d->chk_lpt_sz2 = d->chk_lpt_sz;
        d->chk_lpt_sz = 0;
        d->chk_lpt_wastage = 0;
        d->chk_lpt_lebs = 0;
        d->new_nhead_offs = len;
        return err;
    case 4:
        d->chk_lpt_sz += len;
        d->chk_lpt_wastage += len;
        return 0;
    default:
        return -EINVAL;
    }
}

static void dump_lpt_leb(const struct ubifs_info *c, int lnum)
{
    int err, len = c->leb_size, node_type, node_num, node_len, offs;
    void *buf, *p;

    pr_err("(pid %d) start dumping LEB %d\n", current->pid, lnum);
    buf = p = __vmalloc(c->leb_size, GFP_NOFS, PAGE_KERNEL);
    if (!buf) {
        ubifs_err("cannot allocate memory to dump LPT");
        return;
    }

    err = ubifs_leb_read(c, lnum, buf, 0, c->leb_size, 1);
    if (err)
        goto out;

    while (1) {
        offs = c->leb_size - len;
        if (!is_a_node(c, p, len)) {
            int pad_len;

            pad_len = get_pad_len(c, p, len);
            if (pad_len) {
                pr_err("LEB %d:%d, pad %d bytes\n",
                       lnum, offs, pad_len);
                p += pad_len;
                len -= pad_len;
                continue;
            }
            if (len)
                pr_err("LEB %d:%d, free %d bytes\n",
                       lnum, offs, len);
            break;
        }

        node_type = get_lpt_node_type(c, p, &node_num);
        switch (node_type) {
        case UBIFS_LPT_PNODE:
        {
            node_len = c->pnode_sz;
            if (c->big_lpt)
                pr_err("LEB %d:%d, pnode num %d\n",
                       lnum, offs, node_num);
            else
                pr_err("LEB %d:%d, pnode\n", lnum, offs);
            break;
        }
        case UBIFS_LPT_NNODE:
        {
            int i;
            struct ubifs_nnode nnode;

            node_len = c->nnode_sz;
            if (c->big_lpt)
                pr_err("LEB %d:%d, nnode num %d, ",
                       lnum, offs, node_num);
            else
                pr_err("LEB %d:%d, nnode, ",
                       lnum, offs);
            err = ubifs_unpack_nnode(c, p, &nnode);
            for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
                pr_cont("%d:%d", nnode.nbranch[i].lnum,
                       nnode.nbranch[i].offs);
                if (i != UBIFS_LPT_FANOUT - 1)
                    pr_cont(", ");
            }
            pr_cont("\n");
            break;
        }
        case UBIFS_LPT_LTAB:
            node_len = c->ltab_sz;
            pr_err("LEB %d:%d, ltab\n", lnum, offs);
            break;
        case UBIFS_LPT_LSAVE:
            node_len = c->lsave_sz;
            pr_err("LEB %d:%d, lsave len\n", lnum, offs);
            break;
        default:
            ubifs_err("LPT node type %d not recognized", node_type);
            goto out;
        }

        p += node_len;
        len -= node_len;
    }

    pr_err("(pid %d) finish dumping LEB %d\n", current->pid, lnum);
out:
    vfree(buf);
    return;
}

void ubifs_dump_lpt_lebs(const struct ubifs_info *c)
{
    int i;

    pr_err("(pid %d) start dumping all LPT LEBs\n", current->pid);
    for (i = 0; i < c->lpt_lebs; i++)
        dump_lpt_leb(c, i + c->lpt_first);
    pr_err("(pid %d) finish dumping all LPT LEBs\n", current->pid);
}

static int dbg_populate_lsave(struct ubifs_info *c)
{
    struct ubifs_lprops *lprops;
    struct ubifs_lpt_heap *heap;
    int i;

    if (!dbg_is_chk_gen(c))
        return 0;
    if (random32() & 3)
        return 0;

    for (i = 0; i < c->lsave_cnt; i++)
        c->lsave[i] = c->main_first;

    list_for_each_entry(lprops, &c->empty_list, list)
        c->lsave[random32() % c->lsave_cnt] = lprops->lnum;
    list_for_each_entry(lprops, &c->freeable_list, list)
        c->lsave[random32() % c->lsave_cnt] = lprops->lnum;
    list_for_each_entry(lprops, &c->frdi_idx_list, list)
        c->lsave[random32() % c->lsave_cnt] = lprops->lnum;

    heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
    for (i = 0; i < heap->cnt; i++)
        c->lsave[random32() % c->lsave_cnt] = heap->arr[i]->lnum;
    heap = &c->lpt_heap[LPROPS_DIRTY - 1];
    for (i = 0; i < heap->cnt; i++)
        c->lsave[random32() % c->lsave_cnt] = heap->arr[i]->lnum;
    heap = &c->lpt_heap[LPROPS_FREE - 1];
    for (i = 0; i < heap->cnt; i++)
        c->lsave[random32() % c->lsave_cnt] = heap->arr[i]->lnum;

    return 1;
}