Merge branch 's3c-move' into devel

[linux-2.6] / fs / ubifs / debug.c

/*
 * 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: Artem Bityutskiy (Битюцкий Артём)
 *          Adrian Hunter
 */

/*
 * This file implements most of the debugging stuff which is compiled in only
 * when it is enabled. But some debugging check functions are implemented in
 * corresponding subsystem, just because they are closely related and utilize
 * various local functions of those subsystems.
 */

#define UBIFS_DBG_PRESERVE_UBI

#include "ubifs.h"
#include <linux/module.h>
#include <linux/moduleparam.h>

#ifdef CONFIG_UBIFS_FS_DEBUG

DEFINE_SPINLOCK(dbg_lock);

static char dbg_key_buf0[128];
static char dbg_key_buf1[128];

unsigned int ubifs_msg_flags = UBIFS_MSG_FLAGS_DEFAULT;
unsigned int ubifs_chk_flags = UBIFS_CHK_FLAGS_DEFAULT;
unsigned int ubifs_tst_flags;

module_param_named(debug_msgs, ubifs_msg_flags, uint, S_IRUGO | S_IWUSR);
module_param_named(debug_chks, ubifs_chk_flags, uint, S_IRUGO | S_IWUSR);
module_param_named(debug_tsts, ubifs_tst_flags, uint, S_IRUGO | S_IWUSR);

MODULE_PARM_DESC(debug_msgs, "Debug message type flags");
MODULE_PARM_DESC(debug_chks, "Debug check flags");
MODULE_PARM_DESC(debug_tsts, "Debug special test flags");

static const char *get_key_fmt(int fmt)
{
        switch (fmt) {
        case UBIFS_SIMPLE_KEY_FMT:
                return "simple";
        default:
                return "unknown/invalid format";
        }
}

static const char *get_key_hash(int hash)
{
        switch (hash) {
        case UBIFS_KEY_HASH_R5:
                return "R5";
        case UBIFS_KEY_HASH_TEST:
                return "test";
        default:
                return "unknown/invalid name hash";
        }
}

static const char *get_key_type(int type)
{
        switch (type) {
        case UBIFS_INO_KEY:
                return "inode";
        case UBIFS_DENT_KEY:
                return "direntry";
        case UBIFS_XENT_KEY:
                return "xentry";
        case UBIFS_DATA_KEY:
                return "data";
        case UBIFS_TRUN_KEY:
                return "truncate";
        default:
                return "unknown/invalid key";
        }
}

static void sprintf_key(const struct ubifs_info *c, const union ubifs_key *key,
                        char *buffer)
{
        char *p = buffer;
        int type = key_type(c, key);

        if (c->key_fmt == UBIFS_SIMPLE_KEY_FMT) {
                switch (type) {
                case UBIFS_INO_KEY:
                        sprintf(p, "(%lu, %s)", key_inum(c, key),
                               get_key_type(type));
                        break;
                case UBIFS_DENT_KEY:
                case UBIFS_XENT_KEY:
                        sprintf(p, "(%lu, %s, %#08x)", key_inum(c, key),
                                get_key_type(type), key_hash(c, key));
                        break;
                case UBIFS_DATA_KEY:
                        sprintf(p, "(%lu, %s, %u)", key_inum(c, key),
                                get_key_type(type), key_block(c, key));
                        break;
                case UBIFS_TRUN_KEY:
                        sprintf(p, "(%lu, %s)",
                                key_inum(c, key), get_key_type(type));
                        break;
                default:
                        sprintf(p, "(bad key type: %#08x, %#08x)",
                                key->u32[0], key->u32[1]);
                }
        } else
                sprintf(p, "bad key format %d", c->key_fmt);
}

const char *dbg_key_str0(const struct ubifs_info *c, const union ubifs_key *key)
{
        /* dbg_lock must be held */
        sprintf_key(c, key, dbg_key_buf0);
        return dbg_key_buf0;
}

const char *dbg_key_str1(const struct ubifs_info *c, const union ubifs_key *key)
{
        /* dbg_lock must be held */
        sprintf_key(c, key, dbg_key_buf1);
        return dbg_key_buf1;
}

const char *dbg_ntype(int type)
{
        switch (type) {
        case UBIFS_PAD_NODE:
                return "padding node";
        case UBIFS_SB_NODE:
                return "superblock node";
        case UBIFS_MST_NODE:
                return "master node";
        case UBIFS_REF_NODE:
                return "reference node";
        case UBIFS_INO_NODE:
                return "inode node";
        case UBIFS_DENT_NODE:
                return "direntry node";
        case UBIFS_XENT_NODE:
                return "xentry node";
        case UBIFS_DATA_NODE:
                return "data node";
        case UBIFS_TRUN_NODE:
                return "truncate node";
        case UBIFS_IDX_NODE:
                return "indexing node";
        case UBIFS_CS_NODE:
                return "commit start node";
        case UBIFS_ORPH_NODE:
                return "orphan node";
        default:
                return "unknown node";
        }
}

static const char *dbg_gtype(int type)
{
        switch (type) {
        case UBIFS_NO_NODE_GROUP:
                return "no node group";
        case UBIFS_IN_NODE_GROUP:
                return "in node group";
        case UBIFS_LAST_OF_NODE_GROUP:
                return "last of node group";
        default:
                return "unknown";
        }
}

const char *dbg_cstate(int cmt_state)
{
        switch (cmt_state) {
        case COMMIT_RESTING:
                return "commit resting";
        case COMMIT_BACKGROUND:
                return "background commit requested";
        case COMMIT_REQUIRED:
                return "commit required";
        case COMMIT_RUNNING_BACKGROUND:
                return "BACKGROUND commit running";
        case COMMIT_RUNNING_REQUIRED:
                return "commit running and required";
        case COMMIT_BROKEN:
                return "broken commit";
        default:
                return "unknown commit state";
        }
}

static void dump_ch(const struct ubifs_ch *ch)
{
        printk(KERN_DEBUG "\tmagic          %#x\n", le32_to_cpu(ch->magic));
        printk(KERN_DEBUG "\tcrc            %#x\n", le32_to_cpu(ch->crc));
        printk(KERN_DEBUG "\tnode_type      %d (%s)\n", ch->node_type,
               dbg_ntype(ch->node_type));
        printk(KERN_DEBUG "\tgroup_type     %d (%s)\n", ch->group_type,
               dbg_gtype(ch->group_type));
        printk(KERN_DEBUG "\tsqnum          %llu\n",
               (unsigned long long)le64_to_cpu(ch->sqnum));
        printk(KERN_DEBUG "\tlen            %u\n", le32_to_cpu(ch->len));
}

void dbg_dump_inode(const struct ubifs_info *c, const struct inode *inode)
{
        const struct ubifs_inode *ui = ubifs_inode(inode);

        printk(KERN_DEBUG "inode      %lu\n", inode->i_ino);
        printk(KERN_DEBUG "size       %llu\n",
               (unsigned long long)i_size_read(inode));
        printk(KERN_DEBUG "nlink      %u\n", inode->i_nlink);
        printk(KERN_DEBUG "uid        %u\n", (unsigned int)inode->i_uid);
        printk(KERN_DEBUG "gid        %u\n", (unsigned int)inode->i_gid);
        printk(KERN_DEBUG "atime      %u.%u\n",
               (unsigned int)inode->i_atime.tv_sec,
               (unsigned int)inode->i_atime.tv_nsec);
        printk(KERN_DEBUG "mtime      %u.%u\n",
               (unsigned int)inode->i_mtime.tv_sec,
               (unsigned int)inode->i_mtime.tv_nsec);
        printk(KERN_DEBUG "ctime       %u.%u\n",
               (unsigned int)inode->i_ctime.tv_sec,
               (unsigned int)inode->i_ctime.tv_nsec);
        printk(KERN_DEBUG "creat_sqnum %llu\n", ui->creat_sqnum);
        printk(KERN_DEBUG "xattr_size  %u\n", ui->xattr_size);
        printk(KERN_DEBUG "xattr_cnt   %u\n", ui->xattr_cnt);
        printk(KERN_DEBUG "xattr_names %u\n", ui->xattr_names);
        printk(KERN_DEBUG "dirty       %u\n", ui->dirty);
        printk(KERN_DEBUG "xattr       %u\n", ui->xattr);
        printk(KERN_DEBUG "flags       %d\n", ui->flags);
        printk(KERN_DEBUG "compr_type  %d\n", ui->compr_type);
        printk(KERN_DEBUG "data_len    %d\n", ui->data_len);
}

void dbg_dump_node(const struct ubifs_info *c, const void *node)
{
        int i, n;
        union ubifs_key key;
        const struct ubifs_ch *ch = node;

        if (dbg_failure_mode)
                return;

        /* If the magic is incorrect, just hexdump the first bytes */
        if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC) {
                printk(KERN_DEBUG "Not a node, first %zu bytes:", UBIFS_CH_SZ);
                print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
                               (void *)node, UBIFS_CH_SZ, 1);
                return;
        }

        spin_lock(&dbg_lock);
        dump_ch(node);

        switch (ch->node_type) {
        case UBIFS_PAD_NODE:
        {
                const struct ubifs_pad_node *pad = node;

                printk(KERN_DEBUG "\tpad_len        %u\n",
                       le32_to_cpu(pad->pad_len));
                break;
        }
        case UBIFS_SB_NODE:
        {
                const struct ubifs_sb_node *sup = node;
                unsigned int sup_flags = le32_to_cpu(sup->flags);

                printk(KERN_DEBUG "\tkey_hash       %d (%s)\n",
                       (int)sup->key_hash, get_key_hash(sup->key_hash));
                printk(KERN_DEBUG "\tkey_fmt        %d (%s)\n",
                       (int)sup->key_fmt, get_key_fmt(sup->key_fmt));
                printk(KERN_DEBUG "\tflags          %#x\n", sup_flags);
                printk(KERN_DEBUG "\t  big_lpt      %u\n",
                       !!(sup_flags & UBIFS_FLG_BIGLPT));
                printk(KERN_DEBUG "\tmin_io_size    %u\n",
                       le32_to_cpu(sup->min_io_size));
                printk(KERN_DEBUG "\tleb_size       %u\n",
                       le32_to_cpu(sup->leb_size));
                printk(KERN_DEBUG "\tleb_cnt        %u\n",
                       le32_to_cpu(sup->leb_cnt));
                printk(KERN_DEBUG "\tmax_leb_cnt    %u\n",
                       le32_to_cpu(sup->max_leb_cnt));
                printk(KERN_DEBUG "\tmax_bud_bytes  %llu\n",
                       (unsigned long long)le64_to_cpu(sup->max_bud_bytes));
                printk(KERN_DEBUG "\tlog_lebs       %u\n",
                       le32_to_cpu(sup->log_lebs));
                printk(KERN_DEBUG "\tlpt_lebs       %u\n",
                       le32_to_cpu(sup->lpt_lebs));
                printk(KERN_DEBUG "\torph_lebs      %u\n",
                       le32_to_cpu(sup->orph_lebs));
                printk(KERN_DEBUG "\tjhead_cnt      %u\n",
                       le32_to_cpu(sup->jhead_cnt));
                printk(KERN_DEBUG "\tfanout         %u\n",
                       le32_to_cpu(sup->fanout));
                printk(KERN_DEBUG "\tlsave_cnt      %u\n",
                       le32_to_cpu(sup->lsave_cnt));
                printk(KERN_DEBUG "\tdefault_compr  %u\n",
                       (int)le16_to_cpu(sup->default_compr));
                printk(KERN_DEBUG "\trp_size        %llu\n",
                       (unsigned long long)le64_to_cpu(sup->rp_size));
                printk(KERN_DEBUG "\trp_uid         %u\n",
                       le32_to_cpu(sup->rp_uid));
                printk(KERN_DEBUG "\trp_gid         %u\n",
                       le32_to_cpu(sup->rp_gid));
                printk(KERN_DEBUG "\tfmt_version    %u\n",
                       le32_to_cpu(sup->fmt_version));
                printk(KERN_DEBUG "\ttime_gran      %u\n",
                       le32_to_cpu(sup->time_gran));
                printk(KERN_DEBUG "\tUUID           %02X%02X%02X%02X-%02X%02X"
                       "-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X\n",
                       sup->uuid[0], sup->uuid[1], sup->uuid[2], sup->uuid[3],
                       sup->uuid[4], sup->uuid[5], sup->uuid[6], sup->uuid[7],
                       sup->uuid[8], sup->uuid[9], sup->uuid[10], sup->uuid[11],
                       sup->uuid[12], sup->uuid[13], sup->uuid[14],
                       sup->uuid[15]);
                break;
        }
        case UBIFS_MST_NODE:
        {
                const struct ubifs_mst_node *mst = node;

                printk(KERN_DEBUG "\thighest_inum   %llu\n",
                       (unsigned long long)le64_to_cpu(mst->highest_inum));
                printk(KERN_DEBUG "\tcommit number  %llu\n",
                       (unsigned long long)le64_to_cpu(mst->cmt_no));
                printk(KERN_DEBUG "\tflags          %#x\n",
                       le32_to_cpu(mst->flags));
                printk(KERN_DEBUG "\tlog_lnum       %u\n",
                       le32_to_cpu(mst->log_lnum));
                printk(KERN_DEBUG "\troot_lnum      %u\n",
                       le32_to_cpu(mst->root_lnum));
                printk(KERN_DEBUG "\troot_offs      %u\n",
                       le32_to_cpu(mst->root_offs));
                printk(KERN_DEBUG "\troot_len       %u\n",
                       le32_to_cpu(mst->root_len));
                printk(KERN_DEBUG "\tgc_lnum        %u\n",
                       le32_to_cpu(mst->gc_lnum));
                printk(KERN_DEBUG "\tihead_lnum     %u\n",
                       le32_to_cpu(mst->ihead_lnum));
                printk(KERN_DEBUG "\tihead_offs     %u\n",
                       le32_to_cpu(mst->ihead_offs));
                printk(KERN_DEBUG "\tindex_size     %u\n",
                       le32_to_cpu(mst->index_size));
                printk(KERN_DEBUG "\tlpt_lnum       %u\n",
                       le32_to_cpu(mst->lpt_lnum));
                printk(KERN_DEBUG "\tlpt_offs       %u\n",
                       le32_to_cpu(mst->lpt_offs));
                printk(KERN_DEBUG "\tnhead_lnum     %u\n",
                       le32_to_cpu(mst->nhead_lnum));
                printk(KERN_DEBUG "\tnhead_offs     %u\n",
                       le32_to_cpu(mst->nhead_offs));
                printk(KERN_DEBUG "\tltab_lnum      %u\n",
                       le32_to_cpu(mst->ltab_lnum));
                printk(KERN_DEBUG "\tltab_offs      %u\n",
                       le32_to_cpu(mst->ltab_offs));
                printk(KERN_DEBUG "\tlsave_lnum     %u\n",
                       le32_to_cpu(mst->lsave_lnum));
                printk(KERN_DEBUG "\tlsave_offs     %u\n",
                       le32_to_cpu(mst->lsave_offs));
                printk(KERN_DEBUG "\tlscan_lnum     %u\n",
                       le32_to_cpu(mst->lscan_lnum));
                printk(KERN_DEBUG "\tleb_cnt        %u\n",
                       le32_to_cpu(mst->leb_cnt));
                printk(KERN_DEBUG "\tempty_lebs     %u\n",
                       le32_to_cpu(mst->empty_lebs));
                printk(KERN_DEBUG "\tidx_lebs       %u\n",
                       le32_to_cpu(mst->idx_lebs));
                printk(KERN_DEBUG "\ttotal_free     %llu\n",
                       (unsigned long long)le64_to_cpu(mst->total_free));
                printk(KERN_DEBUG "\ttotal_dirty    %llu\n",
                       (unsigned long long)le64_to_cpu(mst->total_dirty));
                printk(KERN_DEBUG "\ttotal_used     %llu\n",
                       (unsigned long long)le64_to_cpu(mst->total_used));
                printk(KERN_DEBUG "\ttotal_dead     %llu\n",
                       (unsigned long long)le64_to_cpu(mst->total_dead));
                printk(KERN_DEBUG "\ttotal_dark     %llu\n",
                       (unsigned long long)le64_to_cpu(mst->total_dark));
                break;
        }
        case UBIFS_REF_NODE:
        {
                const struct ubifs_ref_node *ref = node;

                printk(KERN_DEBUG "\tlnum           %u\n",
                       le32_to_cpu(ref->lnum));
                printk(KERN_DEBUG "\toffs           %u\n",
                       le32_to_cpu(ref->offs));
                printk(KERN_DEBUG "\tjhead          %u\n",
                       le32_to_cpu(ref->jhead));
                break;
        }
        case UBIFS_INO_NODE:
        {
                const struct ubifs_ino_node *ino = node;

                key_read(c, &ino->key, &key);
                printk(KERN_DEBUG "\tkey            %s\n", DBGKEY(&key));
                printk(KERN_DEBUG "\tcreat_sqnum    %llu\n",
                       (unsigned long long)le64_to_cpu(ino->creat_sqnum));
                printk(KERN_DEBUG "\tsize           %llu\n",
                       (unsigned long long)le64_to_cpu(ino->size));
                printk(KERN_DEBUG "\tnlink          %u\n",
                       le32_to_cpu(ino->nlink));
                printk(KERN_DEBUG "\tatime          %lld.%u\n",
                       (long long)le64_to_cpu(ino->atime_sec),
                       le32_to_cpu(ino->atime_nsec));
                printk(KERN_DEBUG "\tmtime          %lld.%u\n",
                       (long long)le64_to_cpu(ino->mtime_sec),
                       le32_to_cpu(ino->mtime_nsec));
                printk(KERN_DEBUG "\tctime          %lld.%u\n",
                       (long long)le64_to_cpu(ino->ctime_sec),
                       le32_to_cpu(ino->ctime_nsec));
                printk(KERN_DEBUG "\tuid            %u\n",
                       le32_to_cpu(ino->uid));
                printk(KERN_DEBUG "\tgid            %u\n",
                       le32_to_cpu(ino->gid));
                printk(KERN_DEBUG "\tmode           %u\n",
                       le32_to_cpu(ino->mode));
                printk(KERN_DEBUG "\tflags          %#x\n",
                       le32_to_cpu(ino->flags));
                printk(KERN_DEBUG "\txattr_cnt      %u\n",
                       le32_to_cpu(ino->xattr_cnt));
                printk(KERN_DEBUG "\txattr_size     %u\n",
                       le32_to_cpu(ino->xattr_size));
                printk(KERN_DEBUG "\txattr_names    %u\n",
                       le32_to_cpu(ino->xattr_names));
                printk(KERN_DEBUG "\tcompr_type     %#x\n",
                       (int)le16_to_cpu(ino->compr_type));
                printk(KERN_DEBUG "\tdata len       %u\n",
                       le32_to_cpu(ino->data_len));
                break;
        }
        case UBIFS_DENT_NODE:
        case UBIFS_XENT_NODE:
        {
                const struct ubifs_dent_node *dent = node;
                int nlen = le16_to_cpu(dent->nlen);

                key_read(c, &dent->key, &key);
                printk(KERN_DEBUG "\tkey            %s\n", DBGKEY(&key));
                printk(KERN_DEBUG "\tinum           %llu\n",
                       (unsigned long long)le64_to_cpu(dent->inum));
                printk(KERN_DEBUG "\ttype           %d\n", (int)dent->type);
                printk(KERN_DEBUG "\tnlen           %d\n", nlen);
                printk(KERN_DEBUG "\tname           ");

                if (nlen > UBIFS_MAX_NLEN)
                        printk(KERN_DEBUG "(bad name length, not printing, "
                                          "bad or corrupted node)");
                else {
                        for (i = 0; i < nlen && dent->name[i]; i++)
                                printk("%c", dent->name[i]);
                }
                printk("\n");

                break;
        }
        case UBIFS_DATA_NODE:
        {
                const struct ubifs_data_node *dn = node;
                int dlen = le32_to_cpu(ch->len) - UBIFS_DATA_NODE_SZ;

                key_read(c, &dn->key, &key);
                printk(KERN_DEBUG "\tkey            %s\n", DBGKEY(&key));
                printk(KERN_DEBUG "\tsize           %u\n",
                       le32_to_cpu(dn->size));
                printk(KERN_DEBUG "\tcompr_typ      %d\n",
                       (int)le16_to_cpu(dn->compr_type));
                printk(KERN_DEBUG "\tdata size      %d\n",
                       dlen);
                printk(KERN_DEBUG "\tdata:\n");
                print_hex_dump(KERN_DEBUG, "\t", DUMP_PREFIX_OFFSET, 32, 1,
                               (void *)&dn->data, dlen, 0);
                break;
        }
        case UBIFS_TRUN_NODE:
        {
                const struct ubifs_trun_node *trun = node;

                printk(KERN_DEBUG "\tinum           %u\n",
                       le32_to_cpu(trun->inum));
                printk(KERN_DEBUG "\told_size       %llu\n",
                       (unsigned long long)le64_to_cpu(trun->old_size));
                printk(KERN_DEBUG "\tnew_size       %llu\n",
                       (unsigned long long)le64_to_cpu(trun->new_size));
                break;
        }
        case UBIFS_IDX_NODE:
        {
                const struct ubifs_idx_node *idx = node;

                n = le16_to_cpu(idx->child_cnt);
                printk(KERN_DEBUG "\tchild_cnt      %d\n", n);
                printk(KERN_DEBUG "\tlevel          %d\n",
                       (int)le16_to_cpu(idx->level));
                printk(KERN_DEBUG "\tBranches:\n");

                for (i = 0; i < n && i < c->fanout - 1; i++) {
                        const struct ubifs_branch *br;

                        br = ubifs_idx_branch(c, idx, i);
                        key_read(c, &br->key, &key);
                        printk(KERN_DEBUG "\t%d: LEB %d:%d len %d key %s\n",
                               i, le32_to_cpu(br->lnum), le32_to_cpu(br->offs),
                               le32_to_cpu(br->len), DBGKEY(&key));
                }
                break;
        }
        case UBIFS_CS_NODE:
                break;
        case UBIFS_ORPH_NODE:
        {
                const struct ubifs_orph_node *orph = node;

                printk(KERN_DEBUG "\tcommit number  %llu\n",
                       (unsigned long long)
                                le64_to_cpu(orph->cmt_no) & LLONG_MAX);
                printk(KERN_DEBUG "\tlast node flag %llu\n",
                       (unsigned long long)(le64_to_cpu(orph->cmt_no)) >> 63);
                n = (le32_to_cpu(ch->len) - UBIFS_ORPH_NODE_SZ) >> 3;
                printk(KERN_DEBUG "\t%d orphan inode numbers:\n", n);
                for (i = 0; i < n; i++)
                        printk(KERN_DEBUG "\t  ino %llu\n",
                               (unsigned long long)le64_to_cpu(orph->inos[i]));
                break;
        }
        default:
                printk(KERN_DEBUG "node type %d was not recognized\n",
                       (int)ch->node_type);
        }
        spin_unlock(&dbg_lock);
}

void dbg_dump_budget_req(const struct ubifs_budget_req *req)
{
        spin_lock(&dbg_lock);
        printk(KERN_DEBUG "Budgeting request: new_ino %d, dirtied_ino %d\n",
               req->new_ino, req->dirtied_ino);
        printk(KERN_DEBUG "\tnew_ino_d   %d, dirtied_ino_d %d\n",
               req->new_ino_d, req->dirtied_ino_d);
        printk(KERN_DEBUG "\tnew_page    %d, dirtied_page %d\n",
               req->new_page, req->dirtied_page);
        printk(KERN_DEBUG "\tnew_dent    %d, mod_dent     %d\n",
               req->new_dent, req->mod_dent);
        printk(KERN_DEBUG "\tidx_growth  %d\n", req->idx_growth);
        printk(KERN_DEBUG "\tdata_growth %d dd_growth     %d\n",
               req->data_growth, req->dd_growth);
        spin_unlock(&dbg_lock);
}

void dbg_dump_lstats(const struct ubifs_lp_stats *lst)
{
        spin_lock(&dbg_lock);
        printk(KERN_DEBUG "(pid %d) Lprops statistics: empty_lebs %d, "
               "idx_lebs  %d\n", current->pid, lst->empty_lebs, lst->idx_lebs);
        printk(KERN_DEBUG "\ttaken_empty_lebs %d, total_free %lld, "
               "total_dirty %lld\n", lst->taken_empty_lebs, lst->total_free,
               lst->total_dirty);
        printk(KERN_DEBUG "\ttotal_used %lld, total_dark %lld, "
               "total_dead %lld\n", lst->total_used, lst->total_dark,
               lst->total_dead);
        spin_unlock(&dbg_lock);
}

void dbg_dump_budg(struct ubifs_info *c)
{
        int i;
        struct rb_node *rb;
        struct ubifs_bud *bud;
        struct ubifs_gced_idx_leb *idx_gc;

        spin_lock(&dbg_lock);
        printk(KERN_DEBUG "(pid %d) Budgeting info: budg_data_growth %lld, "
               "budg_dd_growth %lld, budg_idx_growth %lld\n", current->pid,
               c->budg_data_growth, c->budg_dd_growth, c->budg_idx_growth);
        printk(KERN_DEBUG "\tdata budget sum %lld, total budget sum %lld, "
               "freeable_cnt %d\n", c->budg_data_growth + c->budg_dd_growth,
               c->budg_data_growth + c->budg_dd_growth + c->budg_idx_growth,
               c->freeable_cnt);
        printk(KERN_DEBUG "\tmin_idx_lebs %d, old_idx_sz %lld, "
               "calc_idx_sz %lld, idx_gc_cnt %d\n", c->min_idx_lebs,
               c->old_idx_sz, c->calc_idx_sz, c->idx_gc_cnt);
        printk(KERN_DEBUG "\tdirty_pg_cnt %ld, dirty_zn_cnt %ld, "
               "clean_zn_cnt %ld\n", atomic_long_read(&c->dirty_pg_cnt),
               atomic_long_read(&c->dirty_zn_cnt),
               atomic_long_read(&c->clean_zn_cnt));
        printk(KERN_DEBUG "\tdark_wm %d, dead_wm %d, max_idx_node_sz %d\n",
               c->dark_wm, c->dead_wm, c->max_idx_node_sz);
        printk(KERN_DEBUG "\tgc_lnum %d, ihead_lnum %d\n",
               c->gc_lnum, c->ihead_lnum);
        for (i = 0; i < c->jhead_cnt; i++)
                printk(KERN_DEBUG "\tjhead %d\t LEB %d\n",
                       c->jheads[i].wbuf.jhead, c->jheads[i].wbuf.lnum);
        for (rb = rb_first(&c->buds); rb; rb = rb_next(rb)) {
                bud = rb_entry(rb, struct ubifs_bud, rb);
                printk(KERN_DEBUG "\tbud LEB %d\n", bud->lnum);
        }
        list_for_each_entry(bud, &c->old_buds, list)
                printk(KERN_DEBUG "\told bud LEB %d\n", bud->lnum);
        list_for_each_entry(idx_gc, &c->idx_gc, list)
                printk(KERN_DEBUG "\tGC'ed idx LEB %d unmap %d\n",
                       idx_gc->lnum, idx_gc->unmap);
        printk(KERN_DEBUG "\tcommit state %d\n", c->cmt_state);
        spin_unlock(&dbg_lock);
}

void dbg_dump_lprop(const struct ubifs_info *c, const struct ubifs_lprops *lp)
{
        printk(KERN_DEBUG "LEB %d lprops: free %d, dirty %d (used %d), "
               "flags %#x\n", lp->lnum, lp->free, lp->dirty,
               c->leb_size - lp->free - lp->dirty, lp->flags);
}

void dbg_dump_lprops(struct ubifs_info *c)
{
        int lnum, err;
        struct ubifs_lprops lp;
        struct ubifs_lp_stats lst;

        printk(KERN_DEBUG "(pid %d) Dumping LEB properties\n", current->pid);
        ubifs_get_lp_stats(c, &lst);
        dbg_dump_lstats(&lst);

        for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
                err = ubifs_read_one_lp(c, lnum, &lp);
                if (err)
                        ubifs_err("cannot read lprops for LEB %d", lnum);

                dbg_dump_lprop(c, &lp);
        }
}

void dbg_dump_leb(const struct ubifs_info *c, int lnum)
{
        struct ubifs_scan_leb *sleb;
        struct ubifs_scan_node *snod;

        if (dbg_failure_mode)
                return;

        printk(KERN_DEBUG "(pid %d) Dumping LEB %d\n", current->pid, lnum);

        sleb = ubifs_scan(c, lnum, 0, c->dbg_buf);
        if (IS_ERR(sleb)) {
                ubifs_err("scan error %d", (int)PTR_ERR(sleb));
                return;
        }

        printk(KERN_DEBUG "LEB %d has %d nodes ending at %d\n", lnum,
               sleb->nodes_cnt, sleb->endpt);

        list_for_each_entry(snod, &sleb->nodes, list) {
                cond_resched();
                printk(KERN_DEBUG "Dumping node at LEB %d:%d len %d\n", lnum,
                       snod->offs, snod->len);
                dbg_dump_node(c, snod->node);
        }

        ubifs_scan_destroy(sleb);
        return;
}

void dbg_dump_znode(const struct ubifs_info *c,
                    const struct ubifs_znode *znode)
{
        int n;
        const struct ubifs_zbranch *zbr;

        spin_lock(&dbg_lock);
        if (znode->parent)
                zbr = &znode->parent->zbranch[znode->iip];
        else
                zbr = &c->zroot;

        printk(KERN_DEBUG "znode %p, LEB %d:%d len %d parent %p iip %d level %d"
               " child_cnt %d flags %lx\n", znode, zbr->lnum, zbr->offs,
               zbr->len, znode->parent, znode->iip, znode->level,
               znode->child_cnt, znode->flags);

        if (znode->child_cnt <= 0 || znode->child_cnt > c->fanout) {
                spin_unlock(&dbg_lock);
                return;
        }

        printk(KERN_DEBUG "zbranches:\n");
        for (n = 0; n < znode->child_cnt; n++) {
                zbr = &znode->zbranch[n];
                if (znode->level > 0)
                        printk(KERN_DEBUG "\t%d: znode %p LEB %d:%d len %d key "
                                          "%s\n", n, zbr->znode, zbr->lnum,
                                          zbr->offs, zbr->len,
                                          DBGKEY(&zbr->key));
                else
                        printk(KERN_DEBUG "\t%d: LNC %p LEB %d:%d len %d key "
                                          "%s\n", n, zbr->znode, zbr->lnum,
                                          zbr->offs, zbr->len,
                                          DBGKEY(&zbr->key));
        }
        spin_unlock(&dbg_lock);
}

void dbg_dump_heap(struct ubifs_info *c, struct ubifs_lpt_heap *heap, int cat)
{
        int i;

        printk(KERN_DEBUG "(pid %d) Dumping heap cat %d (%d elements)\n",
               current->pid, cat, heap->cnt);
        for (i = 0; i < heap->cnt; i++) {
                struct ubifs_lprops *lprops = heap->arr[i];

                printk(KERN_DEBUG "\t%d. LEB %d hpos %d free %d dirty %d "
                       "flags %d\n", i, lprops->lnum, lprops->hpos,
                       lprops->free, lprops->dirty, lprops->flags);
        }
}

void dbg_dump_pnode(struct ubifs_info *c, struct ubifs_pnode *pnode,
                    struct ubifs_nnode *parent, int iip)
{
        int i;

        printk(KERN_DEBUG "(pid %d) Dumping pnode:\n", current->pid);
        printk(KERN_DEBUG "\taddress %zx parent %zx cnext %zx\n",
               (size_t)pnode, (size_t)parent, (size_t)pnode->cnext);
        printk(KERN_DEBUG "\tflags %lu iip %d level %d num %d\n",
               pnode->flags, iip, pnode->level, pnode->num);
        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
                struct ubifs_lprops *lp = &pnode->lprops[i];

                printk(KERN_DEBUG "\t%d: free %d dirty %d flags %d lnum %d\n",
                       i, lp->free, lp->dirty, lp->flags, lp->lnum);
        }
}

void dbg_dump_tnc(struct ubifs_info *c)
{
        struct ubifs_znode *znode;
        int level;

        printk(KERN_DEBUG "\n");
        printk(KERN_DEBUG "(pid %d) Dumping the TNC tree\n", current->pid);
        znode = ubifs_tnc_levelorder_next(c->zroot.znode, NULL);
        level = znode->level;
        printk(KERN_DEBUG "== Level %d ==\n", level);
        while (znode) {
                if (level != znode->level) {
                        level = znode->level;
                        printk(KERN_DEBUG "== Level %d ==\n", level);
                }
                dbg_dump_znode(c, znode);
                znode = ubifs_tnc_levelorder_next(c->zroot.znode, znode);
        }

        printk(KERN_DEBUG "\n");
}

static int dump_znode(struct ubifs_info *c, struct ubifs_znode *znode,
                      void *priv)
{
        dbg_dump_znode(c, znode);
        return 0;
}

/**
 * dbg_dump_index - dump the on-flash index.
 * @c: UBIFS file-system description object
 *
 * This function dumps whole UBIFS indexing B-tree, unlike 'dbg_dump_tnc()'
 * which dumps only in-memory znodes and does not read znodes which from flash.
 */
void dbg_dump_index(struct ubifs_info *c)
{
        dbg_walk_index(c, NULL, dump_znode, NULL);
}

/**
 * dbg_check_synced_i_size - check synchronized inode size.
 * @inode: inode to check
 *
 * If inode is clean, synchronized inode size has to be equivalent to current
 * inode size. This function has to be called only for locked inodes (@i_mutex
 * has to be locked). Returns %0 if synchronized inode size if correct, and
 * %-EINVAL if not.
 */
int dbg_check_synced_i_size(struct inode *inode)
{
        int err = 0;
        struct ubifs_inode *ui = ubifs_inode(inode);

        if (!(ubifs_chk_flags & UBIFS_CHK_GEN))
                return 0;
        if (!S_ISREG(inode->i_mode))
                return 0;

        mutex_lock(&ui->ui_mutex);
        spin_lock(&ui->ui_lock);
        if (ui->ui_size != ui->synced_i_size && !ui->dirty) {
                ubifs_err("ui_size is %lld, synced_i_size is %lld, but inode "
                          "is clean", ui->ui_size, ui->synced_i_size);
                ubifs_err("i_ino %lu, i_mode %#x, i_size %lld", inode->i_ino,
                          inode->i_mode, i_size_read(inode));
                dbg_dump_stack();
                err = -EINVAL;
        }
        spin_unlock(&ui->ui_lock);
        mutex_unlock(&ui->ui_mutex);
        return err;
}

/*
 * dbg_check_dir - check directory inode size and link count.
 * @c: UBIFS file-system description object
 * @dir: the directory to calculate size for
 * @size: the result is returned here
 *
 * This function makes sure that directory size and link count are correct.
 * Returns zero in case of success and a negative error code in case of
 * failure.
 *
 * Note, it is good idea to make sure the @dir->i_mutex is locked before
 * calling this function.
 */
int dbg_check_dir_size(struct ubifs_info *c, const struct inode *dir)
{
        unsigned int nlink = 2;
        union ubifs_key key;
        struct ubifs_dent_node *dent, *pdent = NULL;
        struct qstr nm = { .name = NULL };
        loff_t size = UBIFS_INO_NODE_SZ;

        if (!(ubifs_chk_flags & UBIFS_CHK_GEN))
                return 0;

        if (!S_ISDIR(dir->i_mode))
                return 0;

        lowest_dent_key(c, &key, dir->i_ino);
        while (1) {
                int err;

                dent = ubifs_tnc_next_ent(c, &key, &nm);
                if (IS_ERR(dent)) {
                        err = PTR_ERR(dent);
                        if (err == -ENOENT)
                                break;
                        return err;
                }

                nm.name = dent->name;
                nm.len = le16_to_cpu(dent->nlen);
                size += CALC_DENT_SIZE(nm.len);
                if (dent->type == UBIFS_ITYPE_DIR)
                        nlink += 1;
                kfree(pdent);
                pdent = dent;
                key_read(c, &dent->key, &key);
        }
        kfree(pdent);

        if (i_size_read(dir) != size) {
                ubifs_err("directory inode %lu has size %llu, "
                          "but calculated size is %llu", dir->i_ino,
                          (unsigned long long)i_size_read(dir),
                          (unsigned long long)size);
                dump_stack();
                return -EINVAL;
        }
        if (dir->i_nlink != nlink) {
                ubifs_err("directory inode %lu has nlink %u, but calculated "
                          "nlink is %u", dir->i_ino, dir->i_nlink, nlink);
                dump_stack();
                return -EINVAL;
        }

        return 0;
}

/**
 * dbg_check_key_order - make sure that colliding keys are properly ordered.
 * @c: UBIFS file-system description object
 * @zbr1: first zbranch
 * @zbr2: following zbranch
 *
 * In UBIFS indexing B-tree colliding keys has to be sorted in binary order of
 * names of the direntries/xentries which are referred by the keys. This
 * function reads direntries/xentries referred by @zbr1 and @zbr2 and makes
 * sure the name of direntry/xentry referred by @zbr1 is less than
 * direntry/xentry referred by @zbr2. Returns zero if this is true, %1 if not,
 * and a negative error code in case of failure.
 */
static int dbg_check_key_order(struct ubifs_info *c, struct ubifs_zbranch *zbr1,
                               struct ubifs_zbranch *zbr2)
{
        int err, nlen1, nlen2, cmp;
        struct ubifs_dent_node *dent1, *dent2;
        union ubifs_key key;

        ubifs_assert(!keys_cmp(c, &zbr1->key, &zbr2->key));
        dent1 = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
        if (!dent1)
                return -ENOMEM;
        dent2 = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
        if (!dent2) {
                err = -ENOMEM;
                goto out_free;
        }

        err = ubifs_tnc_read_node(c, zbr1, dent1);
        if (err)
                goto out_free;
        err = ubifs_validate_entry(c, dent1);
        if (err)
                goto out_free;

        err = ubifs_tnc_read_node(c, zbr2, dent2);
        if (err)
                goto out_free;
        err = ubifs_validate_entry(c, dent2);
        if (err)
                goto out_free;

        /* Make sure node keys are the same as in zbranch */
        err = 1;
        key_read(c, &dent1->key, &key);
        if (keys_cmp(c, &zbr1->key, &key)) {
                dbg_err("1st entry at %d:%d has key %s", zbr1->lnum,
                        zbr1->offs, DBGKEY(&key));
                dbg_err("but it should have key %s according to tnc",
                        DBGKEY(&zbr1->key));
                        dbg_dump_node(c, dent1);
                        goto out_free;
        }

        key_read(c, &dent2->key, &key);
        if (keys_cmp(c, &zbr2->key, &key)) {
                dbg_err("2nd entry at %d:%d has key %s", zbr1->lnum,
                        zbr1->offs, DBGKEY(&key));
                dbg_err("but it should have key %s according to tnc",
                        DBGKEY(&zbr2->key));
                        dbg_dump_node(c, dent2);
                        goto out_free;
        }

        nlen1 = le16_to_cpu(dent1->nlen);
        nlen2 = le16_to_cpu(dent2->nlen);

        cmp = memcmp(dent1->name, dent2->name, min_t(int, nlen1, nlen2));
        if (cmp < 0 || (cmp == 0 && nlen1 < nlen2)) {
                err = 0;
                goto out_free;
        }
        if (cmp == 0 && nlen1 == nlen2)
                dbg_err("2 xent/dent nodes with the same name");
        else
                dbg_err("bad order of colliding key %s",
                        DBGKEY(&key));

        dbg_msg("first node at %d:%d\n", zbr1->lnum, zbr1->offs);
        dbg_dump_node(c, dent1);
        dbg_msg("second node at %d:%d\n", zbr2->lnum, zbr2->offs);
        dbg_dump_node(c, dent2);

out_free:
        kfree(dent2);
        kfree(dent1);
        return err;
}

/**
 * dbg_check_znode - check if znode is all right.
 * @c: UBIFS file-system description object
 * @zbr: zbranch which points to this znode
 *
 * This function makes sure that znode referred to by @zbr is all right.
 * Returns zero if it is, and %-EINVAL if it is not.
 */
static int dbg_check_znode(struct ubifs_info *c, struct ubifs_zbranch *zbr)
{
        struct ubifs_znode *znode = zbr->znode;
        struct ubifs_znode *zp = znode->parent;
        int n, err, cmp;

        if (znode->child_cnt <= 0 || znode->child_cnt > c->fanout) {
                err = 1;
                goto out;
        }
        if (znode->level < 0) {
                err = 2;
                goto out;
        }
        if (znode->iip < 0 || znode->iip >= c->fanout) {
                err = 3;
                goto out;
        }

        if (zbr->len == 0)
                /* Only dirty zbranch may have no on-flash nodes */
                if (!ubifs_zn_dirty(znode)) {
                        err = 4;
                        goto out;
                }

        if (ubifs_zn_dirty(znode)) {
                /*
                 * If znode is dirty, its parent has to be dirty as well. The
                 * order of the operation is important, so we have to have
                 * memory barriers.
                 */
                smp_mb();
                if (zp && !ubifs_zn_dirty(zp)) {
                        /*
                         * The dirty flag is atomic and is cleared outside the
                         * TNC mutex, so znode's dirty flag may now have
                         * been cleared. The child is always cleared before the
                         * parent, so we just need to check again.
                         */
                        smp_mb();
                        if (ubifs_zn_dirty(znode)) {
                                err = 5;
                                goto out;
                        }
                }
        }

        if (zp) {
                const union ubifs_key *min, *max;

                if (znode->level != zp->level - 1) {
                        err = 6;
                        goto out;
                }

                /* Make sure the 'parent' pointer in our znode is correct */
                err = ubifs_search_zbranch(c, zp, &zbr->key, &n);
                if (!err) {
                        /* This zbranch does not exist in the parent */
                        err = 7;
                        goto out;
                }

                if (znode->iip >= zp->child_cnt) {
                        err = 8;
                        goto out;
                }

                if (znode->iip != n) {
                        /* This may happen only in case of collisions */
                        if (keys_cmp(c, &zp->zbranch[n].key,
                                     &zp->zbranch[znode->iip].key)) {
                                err = 9;
                                goto out;
                        }
                        n = znode->iip;
                }

                /*
                 * Make sure that the first key in our znode is greater than or
                 * equal to the key in the pointing zbranch.
                 */
                min = &zbr->key;
                cmp = keys_cmp(c, min, &znode->zbranch[0].key);
                if (cmp == 1) {
                        err = 10;
                        goto out;
                }

                if (n + 1 < zp->child_cnt) {
                        max = &zp->zbranch[n + 1].key;

                        /*
                         * Make sure the last key in our znode is less or
                         * equivalent than the the key in zbranch which goes
                         * after our pointing zbranch.
                         */
                        cmp = keys_cmp(c, max,
                                &znode->zbranch[znode->child_cnt - 1].key);
                        if (cmp == -1) {
                                err = 11;
                                goto out;
                        }
                }
        } else {
                /* This may only be root znode */
                if (zbr != &c->zroot) {
                        err = 12;
                        goto out;
                }
        }

        /*
         * Make sure that next key is greater or equivalent then the previous
         * one.
         */
        for (n = 1; n < znode->child_cnt; n++) {
                cmp = keys_cmp(c, &znode->zbranch[n - 1].key,
                               &znode->zbranch[n].key);
                if (cmp > 0) {
                        err = 13;
                        goto out;
                }
                if (cmp == 0) {
                        /* This can only be keys with colliding hash */
                        if (!is_hash_key(c, &znode->zbranch[n].key)) {
                                err = 14;
                                goto out;
                        }

                        if (znode->level != 0 || c->replaying)
                                continue;

                        /*
                         * Colliding keys should follow binary order of
                         * corresponding xentry/dentry names.
                         */
                        err = dbg_check_key_order(c, &znode->zbranch[n - 1],
                                                  &znode->zbranch[n]);
                        if (err < 0)
                                return err;
                        if (err) {
                                err = 15;
                                goto out;
                        }
                }
        }

        for (n = 0; n < znode->child_cnt; n++) {
                if (!znode->zbranch[n].znode &&
                    (znode->zbranch[n].lnum == 0 ||
                     znode->zbranch[n].len == 0)) {
                        err = 16;
                        goto out;
                }

                if (znode->zbranch[n].lnum != 0 &&
                    znode->zbranch[n].len == 0) {
                        err = 17;
                        goto out;
                }

                if (znode->zbranch[n].lnum == 0 &&
                    znode->zbranch[n].len != 0) {
                        err = 18;
                        goto out;
                }

                if (znode->zbranch[n].lnum == 0 &&
                    znode->zbranch[n].offs != 0) {
                        err = 19;
                        goto out;
                }

                if (znode->level != 0 && znode->zbranch[n].znode)
                        if (znode->zbranch[n].znode->parent != znode) {
                                err = 20;
                                goto out;
                        }
        }

        return 0;

out:
        ubifs_err("failed, error %d", err);
        ubifs_msg("dump of the znode");
        dbg_dump_znode(c, znode);
        if (zp) {
                ubifs_msg("dump of the parent znode");
                dbg_dump_znode(c, zp);
        }
        dump_stack();
        return -EINVAL;
}

/**
 * dbg_check_tnc - check TNC tree.
 * @c: UBIFS file-system description object
 * @extra: do extra checks that are possible at start commit
 *
 * This function traverses whole TNC tree and checks every znode. Returns zero
 * if everything is all right and %-EINVAL if something is wrong with TNC.
 */
int dbg_check_tnc(struct ubifs_info *c, int extra)
{
        struct ubifs_znode *znode;
        long clean_cnt = 0, dirty_cnt = 0;
        int err, last;

        if (!(ubifs_chk_flags & UBIFS_CHK_TNC))
                return 0;

        ubifs_assert(mutex_is_locked(&c->tnc_mutex));
        if (!c->zroot.znode)
                return 0;

        znode = ubifs_tnc_postorder_first(c->zroot.znode);
        while (1) {
                struct ubifs_znode *prev;
                struct ubifs_zbranch *zbr;

                if (!znode->parent)
                        zbr = &c->zroot;
                else
                        zbr = &znode->parent->zbranch[znode->iip];

                err = dbg_check_znode(c, zbr);
                if (err)
                        return err;

                if (extra) {
                        if (ubifs_zn_dirty(znode))
                                dirty_cnt += 1;
                        else
                                clean_cnt += 1;
                }

                prev = znode;
                znode = ubifs_tnc_postorder_next(znode);
                if (!znode)
                        break;

                /*
                 * If the last key of this znode is equivalent to the first key
                 * of the next znode (collision), then check order of the keys.
                 */
                last = prev->child_cnt - 1;
                if (prev->level == 0 && znode->level == 0 && !c->replaying &&
                    !keys_cmp(c, &prev->zbranch[last].key,
                              &znode->zbranch[0].key)) {
                        err = dbg_check_key_order(c, &prev->zbranch[last],
                                                  &znode->zbranch[0]);
                        if (err < 0)
                                return err;
                        if (err) {
                                ubifs_msg("first znode");
                                dbg_dump_znode(c, prev);
                                ubifs_msg("second znode");
                                dbg_dump_znode(c, znode);
                                return -EINVAL;
                        }
                }
        }

        if (extra) {
                if (clean_cnt != atomic_long_read(&c->clean_zn_cnt)) {
                        ubifs_err("incorrect clean_zn_cnt %ld, calculated %ld",
                                  atomic_long_read(&c->clean_zn_cnt),
                                  clean_cnt);
                        return -EINVAL;
                }
                if (dirty_cnt != atomic_long_read(&c->dirty_zn_cnt)) {
                        ubifs_err("incorrect dirty_zn_cnt %ld, calculated %ld",
                                  atomic_long_read(&c->dirty_zn_cnt),
                                  dirty_cnt);
                        return -EINVAL;
                }
        }

        return 0;
}

/**
 * dbg_walk_index - walk the on-flash index.
 * @c: UBIFS file-system description object
 * @leaf_cb: called for each leaf node
 * @znode_cb: called for each indexing node
 * @priv: private date which is passed to callbacks
 *
 * This function walks the UBIFS index and calls the @leaf_cb for each leaf
 * node and @znode_cb for each indexing node. Returns zero in case of success
 * and a negative error code in case of failure.
 *
 * It would be better if this function removed every znode it pulled to into
 * the TNC, so that the behavior more closely matched the non-debugging
 * behavior.
 */
int dbg_walk_index(struct ubifs_info *c, dbg_leaf_callback leaf_cb,
                   dbg_znode_callback znode_cb, void *priv)
{
        int err;
        struct ubifs_zbranch *zbr;
        struct ubifs_znode *znode, *child;

        mutex_lock(&c->tnc_mutex);
        /* If the root indexing node is not in TNC - pull it */
        if (!c->zroot.znode) {
                c->zroot.znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
                if (IS_ERR(c->zroot.znode)) {
                        err = PTR_ERR(c->zroot.znode);
                        c->zroot.znode = NULL;
                        goto out_unlock;
                }
        }

        /*
         * We are going to traverse the indexing tree in the postorder manner.
         * Go down and find the leftmost indexing node where we are going to
         * start from.
         */
        znode = c->zroot.znode;
        while (znode->level > 0) {
                zbr = &znode->zbranch[0];
                child = zbr->znode;
                if (!child) {
                        child = ubifs_load_znode(c, zbr, znode, 0);
                        if (IS_ERR(child)) {
                                err = PTR_ERR(child);
                                goto out_unlock;
                        }
                        zbr->znode = child;
                }

                znode = child;
        }

        /* Iterate over all indexing nodes */
        while (1) {
                int idx;

                cond_resched();

                if (znode_cb) {
                        err = znode_cb(c, znode, priv);
                        if (err) {
                                ubifs_err("znode checking function returned "
                                          "error %d", err);
                                dbg_dump_znode(c, znode);
                                goto out_dump;
                        }
                }
                if (leaf_cb && znode->level == 0) {
                        for (idx = 0; idx < znode->child_cnt; idx++) {
                                zbr = &znode->zbranch[idx];
                                err = leaf_cb(c, zbr, priv);
                                if (err) {
                                        ubifs_err("leaf checking function "
                                                  "returned error %d, for leaf "
                                                  "at LEB %d:%d",
                                                  err, zbr->lnum, zbr->offs);
                                        goto out_dump;
                                }
                        }
                }

                if (!znode->parent)
                        break;

                idx = znode->iip + 1;
                znode = znode->parent;
                if (idx < znode->child_cnt) {
                        /* Switch to the next index in the parent */
                        zbr = &znode->zbranch[idx];
                        child = zbr->znode;
                        if (!child) {
                                child = ubifs_load_znode(c, zbr, znode, idx);
                                if (IS_ERR(child)) {
                                        err = PTR_ERR(child);
                                        goto out_unlock;
                                }
                                zbr->znode = child;
                        }
                        znode = child;
                } else
                        /*
                         * This is the last child, switch to the parent and
                         * continue.
                         */
                        continue;

                /* Go to the lowest leftmost znode in the new sub-tree */
                while (znode->level > 0) {
                        zbr = &znode->zbranch[0];
                        child = zbr->znode;
                        if (!child) {
                                child = ubifs_load_znode(c, zbr, znode, 0);
                                if (IS_ERR(child)) {
                                        err = PTR_ERR(child);
                                        goto out_unlock;
                                }
                                zbr->znode = child;
                        }
                        znode = child;
                }
        }

        mutex_unlock(&c->tnc_mutex);
        return 0;

out_dump:
        if (znode->parent)
                zbr = &znode->parent->zbranch[znode->iip];
        else
                zbr = &c->zroot;
        ubifs_msg("dump of znode at LEB %d:%d", zbr->lnum, zbr->offs);
        dbg_dump_znode(c, znode);
out_unlock:
        mutex_unlock(&c->tnc_mutex);
        return err;
}

/**
 * add_size - add znode size to partially calculated index size.
 * @c: UBIFS file-system description object
 * @znode: znode to add size for
 * @priv: partially calculated index size
 *
 * This is a helper function for 'dbg_check_idx_size()' which is called for
 * every indexing node and adds its size to the 'long long' variable pointed to
 * by @priv.
 */
static int add_size(struct ubifs_info *c, struct ubifs_znode *znode, void *priv)
{
        long long *idx_size = priv;
        int add;

        add = ubifs_idx_node_sz(c, znode->child_cnt);
        add = ALIGN(add, 8);
        *idx_size += add;
        return 0;
}

/**
 * dbg_check_idx_size - check index size.
 * @c: UBIFS file-system description object
 * @idx_size: size to check
 *
 * This function walks the UBIFS index, calculates its size and checks that the
 * size is equivalent to @idx_size. Returns zero in case of success and a
 * negative error code in case of failure.
 */
int dbg_check_idx_size(struct ubifs_info *c, long long idx_size)
{
        int err;
        long long calc = 0;

        if (!(ubifs_chk_flags & UBIFS_CHK_IDX_SZ))
                return 0;

        err = dbg_walk_index(c, NULL, add_size, &calc);
        if (err) {
                ubifs_err("error %d while walking the index", err);
                return err;
        }

        if (calc != idx_size) {
                ubifs_err("index size check failed: calculated size is %lld, "
                          "should be %lld", calc, idx_size);
                dump_stack();
                return -EINVAL;
        }

        return 0;
}

/**
 * struct fsck_inode - information about an inode used when checking the file-system.
 * @rb: link in the RB-tree of inodes
 * @inum: inode number
 * @mode: inode type, permissions, etc
 * @nlink: inode link count
 * @xattr_cnt: count of extended attributes
 * @references: how many directory/xattr entries refer this inode (calculated
 *              while walking the index)
 * @calc_cnt: for directory inode count of child directories
 * @size: inode size (read from on-flash inode)
 * @xattr_sz: summary size of all extended attributes (read from on-flash
 *            inode)
 * @calc_sz: for directories calculated directory size
 * @calc_xcnt: count of extended attributes
 * @calc_xsz: calculated summary size of all extended attributes
 * @xattr_nms: sum of lengths of all extended attribute names belonging to this
 *             inode (read from on-flash inode)
 * @calc_xnms: calculated sum of lengths of all extended attribute names
 */
struct fsck_inode {
        struct rb_node rb;
        ino_t inum;
        umode_t mode;
        unsigned int nlink;
        unsigned int xattr_cnt;
        int references;
        int calc_cnt;
        long long size;
        unsigned int xattr_sz;
        long long calc_sz;
        long long calc_xcnt;
        long long calc_xsz;
        unsigned int xattr_nms;
        long long calc_xnms;
};

/**
 * struct fsck_data - private FS checking information.
 * @inodes: RB-tree of all inodes (contains @struct fsck_inode objects)
 */
struct fsck_data {
        struct rb_root inodes;
};

/**
 * add_inode - add inode information to RB-tree of inodes.
 * @c: UBIFS file-system description object
 * @fsckd: FS checking information
 * @ino: raw UBIFS inode to add
 *
 * This is a helper function for 'check_leaf()' which adds information about
 * inode @ino to the RB-tree of inodes. Returns inode information pointer in
 * case of success and a negative error code in case of failure.
 */
static struct fsck_inode *add_inode(struct ubifs_info *c,
                                    struct fsck_data *fsckd,
                                    struct ubifs_ino_node *ino)
{
        struct rb_node **p, *parent = NULL;
        struct fsck_inode *fscki;
        ino_t inum = key_inum_flash(c, &ino->key);

        p = &fsckd->inodes.rb_node;
        while (*p) {
                parent = *p;
                fscki = rb_entry(parent, struct fsck_inode, rb);
                if (inum < fscki->inum)
                        p = &(*p)->rb_left;
                else if (inum > fscki->inum)
                        p = &(*p)->rb_right;
                else
                        return fscki;
        }

        if (inum > c->highest_inum) {
                ubifs_err("too high inode number, max. is %lu",
                          c->highest_inum);
                return ERR_PTR(-EINVAL);
        }

        fscki = kzalloc(sizeof(struct fsck_inode), GFP_NOFS);
        if (!fscki)
                return ERR_PTR(-ENOMEM);

        fscki->inum = inum;
        fscki->nlink = le32_to_cpu(ino->nlink);
        fscki->size = le64_to_cpu(ino->size);
        fscki->xattr_cnt = le32_to_cpu(ino->xattr_cnt);
        fscki->xattr_sz = le32_to_cpu(ino->xattr_size);
        fscki->xattr_nms = le32_to_cpu(ino->xattr_names);
        fscki->mode = le32_to_cpu(ino->mode);
        if (S_ISDIR(fscki->mode)) {
                fscki->calc_sz = UBIFS_INO_NODE_SZ;
                fscki->calc_cnt = 2;
        }
        rb_link_node(&fscki->rb, parent, p);
        rb_insert_color(&fscki->rb, &fsckd->inodes);
        return fscki;
}

/**
 * search_inode - search inode in the RB-tree of inodes.
 * @fsckd: FS checking information
 * @inum: inode number to search
 *
 * This is a helper function for 'check_leaf()' which searches inode @inum in
 * the RB-tree of inodes and returns an inode information pointer or %NULL if
 * the inode was not found.
 */
static struct fsck_inode *search_inode(struct fsck_data *fsckd, ino_t inum)
{
        struct rb_node *p;
        struct fsck_inode *fscki;

        p = fsckd->inodes.rb_node;
        while (p) {
                fscki = rb_entry(p, struct fsck_inode, rb);
                if (inum < fscki->inum)
                        p = p->rb_left;
                else if (inum > fscki->inum)
                        p = p->rb_right;
                else
                        return fscki;
        }
        return NULL;
}

/**
 * read_add_inode - read inode node and add it to RB-tree of inodes.
 * @c: UBIFS file-system description object
 * @fsckd: FS checking information
 * @inum: inode number to read
 *
 * This is a helper function for 'check_leaf()' which finds inode node @inum in
 * the index, reads it, and adds it to the RB-tree of inodes. Returns inode
 * information pointer in case of success and a negative error code in case of
 * failure.
 */
static struct fsck_inode *read_add_inode(struct ubifs_info *c,
                                         struct fsck_data *fsckd, ino_t inum)
{
        int n, err;
        union ubifs_key key;
        struct ubifs_znode *znode;
        struct ubifs_zbranch *zbr;
        struct ubifs_ino_node *ino;
        struct fsck_inode *fscki;

        fscki = search_inode(fsckd, inum);
        if (fscki)
                return fscki;

        ino_key_init(c, &key, inum);
        err = ubifs_lookup_level0(c, &key, &znode, &n);
        if (!err) {
                ubifs_err("inode %lu not found in index", inum);
                return ERR_PTR(-ENOENT);
        } else if (err < 0) {
                ubifs_err("error %d while looking up inode %lu", err, inum);
                return ERR_PTR(err);
        }

        zbr = &znode->zbranch[n];
        if (zbr->len < UBIFS_INO_NODE_SZ) {
                ubifs_err("bad node %lu node length %d", inum, zbr->len);
                return ERR_PTR(-EINVAL);
        }

        ino = kmalloc(zbr->len, GFP_NOFS);
        if (!ino)
                return ERR_PTR(-ENOMEM);

        err = ubifs_tnc_read_node(c, zbr, ino);
        if (err) {
                ubifs_err("cannot read inode node at LEB %d:%d, error %d",
                          zbr->lnum, zbr->offs, err);
                kfree(ino);
                return ERR_PTR(err);
        }

        fscki = add_inode(c, fsckd, ino);
        kfree(ino);
        if (IS_ERR(fscki)) {
                ubifs_err("error %ld while adding inode %lu node",
                          PTR_ERR(fscki), inum);
                return fscki;
        }

        return fscki;
}

/**
 * check_leaf - check leaf node.
 * @c: UBIFS file-system description object
 * @zbr: zbranch of the leaf node to check
 * @priv: FS checking information
 *
 * This is a helper function for 'dbg_check_filesystem()' which is called for
 * every single leaf node while walking the indexing tree. It checks that the
 * leaf node referred from the indexing tree exists, has correct CRC, and does
 * some other basic validation. This function is also responsible for building
 * an RB-tree of inodes - it adds all inodes into the RB-tree. It also
 * calculates reference count, size, etc for each inode in order to later
 * compare them to the information stored inside the inodes and detect possible
 * inconsistencies. Returns zero in case of success and a negative error code
 * in case of failure.
 */
static int check_leaf(struct ubifs_info *c, struct ubifs_zbranch *zbr,
                      void *priv)
{
        ino_t inum;
        void *node;
        struct ubifs_ch *ch;
        int err, type = key_type(c, &zbr->key);
        struct fsck_inode *fscki;

        if (zbr->len < UBIFS_CH_SZ) {
                ubifs_err("bad leaf length %d (LEB %d:%d)",
                          zbr->len, zbr->lnum, zbr->offs);
                return -EINVAL;
        }

        node = kmalloc(zbr->len, GFP_NOFS);
        if (!node)
                return -ENOMEM;

        err = ubifs_tnc_read_node(c, zbr, node);
        if (err) {
                ubifs_err("cannot read leaf node at LEB %d:%d, error %d",
                          zbr->lnum, zbr->offs, err);
                goto out_free;
        }

        /* If this is an inode node, add it to RB-tree of inodes */
        if (type == UBIFS_INO_KEY) {
                fscki = add_inode(c, priv, node);
                if (IS_ERR(fscki)) {
                        err = PTR_ERR(fscki);
                        ubifs_err("error %d while adding inode node", err);
                        goto out_dump;
                }
                goto out;
        }

        if (type != UBIFS_DENT_KEY && type != UBIFS_XENT_KEY &&
            type != UBIFS_DATA_KEY) {
                ubifs_err("unexpected node type %d at LEB %d:%d",
                          type, zbr->lnum, zbr->offs);
                err = -EINVAL;
                goto out_free;
        }

        ch = node;
        if (le64_to_cpu(ch->sqnum) > c->max_sqnum) {
                ubifs_err("too high sequence number, max. is %llu",
                          c->max_sqnum);
                err = -EINVAL;
                goto out_dump;
        }

        if (type == UBIFS_DATA_KEY) {
                long long blk_offs;
                struct ubifs_data_node *dn = node;

                /*
                 * Search the inode node this data node belongs to and insert
                 * it to the RB-tree of inodes.
                 */
                inum = key_inum_flash(c, &dn->key);
                fscki = read_add_inode(c, priv, inum);
                if (IS_ERR(fscki)) {
                        err = PTR_ERR(fscki);
                        ubifs_err("error %d while processing data node and "
                                  "trying to find inode node %lu", err, inum);
                        goto out_dump;
                }

                /* Make sure the data node is within inode size */
                blk_offs = key_block_flash(c, &dn->key);
                blk_offs <<= UBIFS_BLOCK_SHIFT;
                blk_offs += le32_to_cpu(dn->size);
                if (blk_offs > fscki->size) {
                        ubifs_err("data node at LEB %d:%d is not within inode "
                                  "size %lld", zbr->lnum, zbr->offs,
                                  fscki->size);
                        err = -EINVAL;
                        goto out_dump;
                }
        } else {
                int nlen;
                struct ubifs_dent_node *dent = node;
                struct fsck_inode *fscki1;

                err = ubifs_validate_entry(c, dent);
                if (err)
                        goto out_dump;

                /*
                 * Search the inode node this entry refers to and the parent
                 * inode node and insert them to the RB-tree of inodes.
                 */
                inum = le64_to_cpu(dent->inum);
                fscki = read_add_inode(c, priv, inum);
                if (IS_ERR(fscki)) {
                        err = PTR_ERR(fscki);
                        ubifs_err("error %d while processing entry node and "
                                  "trying to find inode node %lu", err, inum);
                        goto out_dump;
                }

                /* Count how many direntries or xentries refers this inode */
                fscki->references += 1;

                inum = key_inum_flash(c, &dent->key);
                fscki1 = read_add_inode(c, priv, inum);
                if (IS_ERR(fscki1)) {
                        err = PTR_ERR(fscki);
                        ubifs_err("error %d while processing entry node and "
                                  "trying to find parent inode node %lu",
                                  err, inum);
                        goto out_dump;
                }

                nlen = le16_to_cpu(dent->nlen);
                if (type == UBIFS_XENT_KEY) {
                        fscki1->calc_xcnt += 1;
                        fscki1->calc_xsz += CALC_DENT_SIZE(nlen);
                        fscki1->calc_xsz += CALC_XATTR_BYTES(fscki->size);
                        fscki1->calc_xnms += nlen;
                } else {
                        fscki1->calc_sz += CALC_DENT_SIZE(nlen);
                        if (dent->type == UBIFS_ITYPE_DIR)
                                fscki1->calc_cnt += 1;
                }
        }

out:
        kfree(node);
        return 0;

out_dump:
        ubifs_msg("dump of node at LEB %d:%d", zbr->lnum, zbr->offs);
        dbg_dump_node(c, node);
out_free:
        kfree(node);
        return err;
}

/**
 * free_inodes - free RB-tree of inodes.
 * @fsckd: FS checking information
 */
static void free_inodes(struct fsck_data *fsckd)
{
        struct rb_node *this = fsckd->inodes.rb_node;
        struct fsck_inode *fscki;

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

/**
 * check_inodes - checks all inodes.
 * @c: UBIFS file-system description object
 * @fsckd: FS checking information
 *
 * This is a helper function for 'dbg_check_filesystem()' which walks the
 * RB-tree of inodes after the index scan has been finished, and checks that
 * inode nlink, size, etc are correct. Returns zero if inodes are fine,
 * %-EINVAL if not, and a negative error code in case of failure.
 */
static int check_inodes(struct ubifs_info *c, struct fsck_data *fsckd)
{
        int n, err;
        union ubifs_key key;
        struct ubifs_znode *znode;
        struct ubifs_zbranch *zbr;
        struct ubifs_ino_node *ino;
        struct fsck_inode *fscki;
        struct rb_node *this = rb_first(&fsckd->inodes);

        while (this) {
                fscki = rb_entry(this, struct fsck_inode, rb);
                this = rb_next(this);

                if (S_ISDIR(fscki->mode)) {
                        /*
                         * Directories have to have exactly one reference (they
                         * cannot have hardlinks), although root inode is an
                         * exception.
                         */
                        if (fscki->inum != UBIFS_ROOT_INO &&
                            fscki->references != 1) {
                                ubifs_err("directory inode %lu has %d "
                                          "direntries which refer it, but "
                                          "should be 1", fscki->inum,
                                          fscki->references);
                                goto out_dump;
                        }
                        if (fscki->inum == UBIFS_ROOT_INO &&
                            fscki->references != 0) {
                                ubifs_err("root inode %lu has non-zero (%d) "
                                          "direntries which refer it",
                                          fscki->inum, fscki->references);
                                goto out_dump;
                        }
                        if (fscki->calc_sz != fscki->size) {
                                ubifs_err("directory inode %lu size is %lld, "
                                          "but calculated size is %lld",
                                          fscki->inum, fscki->size,
                                          fscki->calc_sz);
                                goto out_dump;
                        }
                        if (fscki->calc_cnt != fscki->nlink) {
                                ubifs_err("directory inode %lu nlink is %d, "
                                          "but calculated nlink is %d",
                                          fscki->inum, fscki->nlink,
                                          fscki->calc_cnt);
                                goto out_dump;
                        }
                } else {
                        if (fscki->references != fscki->nlink) {
                                ubifs_err("inode %lu nlink is %d, but "
                                          "calculated nlink is %d", fscki->inum,
                                          fscki->nlink, fscki->references);
                                goto out_dump;
                        }
                }
                if (fscki->xattr_sz != fscki->calc_xsz) {
                        ubifs_err("inode %lu has xattr size %u, but "
                                  "calculated size is %lld",
                                  fscki->inum, fscki->xattr_sz,
                                  fscki->calc_xsz);
                        goto out_dump;
                }
                if (fscki->xattr_cnt != fscki->calc_xcnt) {
                        ubifs_err("inode %lu has %u xattrs, but "
                                  "calculated count is %lld", fscki->inum,
                                  fscki->xattr_cnt, fscki->calc_xcnt);
                        goto out_dump;
                }
                if (fscki->xattr_nms != fscki->calc_xnms) {
                        ubifs_err("inode %lu has xattr names' size %u, but "
                                  "calculated names' size is %lld",
                                  fscki->inum, fscki->xattr_nms,
                                  fscki->calc_xnms);
                        goto out_dump;
                }
        }

        return 0;

out_dump:
        /* Read the bad inode and dump it */
        ino_key_init(c, &key, fscki->inum);
        err = ubifs_lookup_level0(c, &key, &znode, &n);
        if (!err) {
                ubifs_err("inode %lu not found in index", fscki->inum);
                return -ENOENT;
        } else if (err < 0) {
                ubifs_err("error %d while looking up inode %lu",
                          err, fscki->inum);
                return err;
        }

        zbr = &znode->zbranch[n];
        ino = kmalloc(zbr->len, GFP_NOFS);
        if (!ino)
                return -ENOMEM;

        err = ubifs_tnc_read_node(c, zbr, ino);
        if (err) {
                ubifs_err("cannot read inode node at LEB %d:%d, error %d",
                          zbr->lnum, zbr->offs, err);
                kfree(ino);
                return err;
        }

        ubifs_msg("dump of the inode %lu sitting in LEB %d:%d",
                  fscki->inum, zbr->lnum, zbr->offs);
        dbg_dump_node(c, ino);
        kfree(ino);
        return -EINVAL;
}

/**
 * dbg_check_filesystem - check the file-system.
 * @c: UBIFS file-system description object
 *
 * This function checks the file system, namely:
 * o makes sure that all leaf nodes exist and their CRCs are correct;
 * o makes sure inode nlink, size, xattr size/count are correct (for all
 *   inodes).
 *
 * The function reads whole indexing tree and all nodes, so it is pretty
 * heavy-weight. Returns zero if the file-system is consistent, %-EINVAL if
 * not, and a negative error code in case of failure.
 */
int dbg_check_filesystem(struct ubifs_info *c)
{
        int err;
        struct fsck_data fsckd;

        if (!(ubifs_chk_flags & UBIFS_CHK_FS))
                return 0;

        fsckd.inodes = RB_ROOT;
        err = dbg_walk_index(c, check_leaf, NULL, &fsckd);
        if (err)
                goto out_free;

        err = check_inodes(c, &fsckd);
        if (err)
                goto out_free;

        free_inodes(&fsckd);
        return 0;

out_free:
        ubifs_err("file-system check failed with error %d", err);
        dump_stack();
        free_inodes(&fsckd);
        return err;
}

static int invocation_cnt;

int dbg_force_in_the_gaps(void)
{
        if (!dbg_force_in_the_gaps_enabled)
                return 0;
        /* Force in-the-gaps every 8th commit */
        return !((invocation_cnt++) & 0x7);
}

/* Failure mode for recovery testing */

#define chance(n, d) (simple_rand() <= (n) * 32768LL / (d))

struct failure_mode_info {
        struct list_head list;
        struct ubifs_info *c;
};

static LIST_HEAD(fmi_list);
static DEFINE_SPINLOCK(fmi_lock);

static unsigned int next;

static int simple_rand(void)
{
        if (next == 0)
                next = current->pid;
        next = next * 1103515245 + 12345;
        return (next >> 16) & 32767;
}

void dbg_failure_mode_registration(struct ubifs_info *c)
{
        struct failure_mode_info *fmi;

        fmi = kmalloc(sizeof(struct failure_mode_info), GFP_NOFS);
        if (!fmi) {
                dbg_err("Failed to register failure mode - no memory");
                return;
        }
        fmi->c = c;
        spin_lock(&fmi_lock);
        list_add_tail(&fmi->list, &fmi_list);
        spin_unlock(&fmi_lock);
}

void dbg_failure_mode_deregistration(struct ubifs_info *c)
{
        struct failure_mode_info *fmi, *tmp;

        spin_lock(&fmi_lock);
        list_for_each_entry_safe(fmi, tmp, &fmi_list, list)
                if (fmi->c == c) {
                        list_del(&fmi->list);
                        kfree(fmi);
                }
        spin_unlock(&fmi_lock);
}

static struct ubifs_info *dbg_find_info(struct ubi_volume_desc *desc)
{
        struct failure_mode_info *fmi;

        spin_lock(&fmi_lock);
        list_for_each_entry(fmi, &fmi_list, list)
                if (fmi->c->ubi == desc) {
                        struct ubifs_info *c = fmi->c;

                        spin_unlock(&fmi_lock);
                        return c;
                }
        spin_unlock(&fmi_lock);
        return NULL;
}

static int in_failure_mode(struct ubi_volume_desc *desc)
{
        struct ubifs_info *c = dbg_find_info(desc);

        if (c && dbg_failure_mode)
                return c->failure_mode;
        return 0;
}

static int do_fail(struct ubi_volume_desc *desc, int lnum, int write)
{
        struct ubifs_info *c = dbg_find_info(desc);

        if (!c || !dbg_failure_mode)
                return 0;
        if (c->failure_mode)
                return 1;
        if (!c->fail_cnt) {
                /* First call - decide delay to failure */
                if (chance(1, 2)) {
                        unsigned int delay = 1 << (simple_rand() >> 11);

                        if (chance(1, 2)) {
                                c->fail_delay = 1;
                                c->fail_timeout = jiffies +
                                                  msecs_to_jiffies(delay);
                                dbg_rcvry("failing after %ums", delay);
                        } else {
                                c->fail_delay = 2;
                                c->fail_cnt_max = delay;
                                dbg_rcvry("failing after %u calls", delay);
                        }
                }
                c->fail_cnt += 1;
        }
        /* Determine if failure delay has expired */
        if (c->fail_delay == 1) {
                if (time_before(jiffies, c->fail_timeout))
                        return 0;
        } else if (c->fail_delay == 2)
                if (c->fail_cnt++ < c->fail_cnt_max)
                        return 0;
        if (lnum == UBIFS_SB_LNUM) {
                if (write) {
                        if (chance(1, 2))
                                return 0;
                } else if (chance(19, 20))
                        return 0;
                dbg_rcvry("failing in super block LEB %d", lnum);
        } else if (lnum == UBIFS_MST_LNUM || lnum == UBIFS_MST_LNUM + 1) {
                if (chance(19, 20))
                        return 0;
                dbg_rcvry("failing in master LEB %d", lnum);
        } else if (lnum >= UBIFS_LOG_LNUM && lnum <= c->log_last) {
                if (write) {
                        if (chance(99, 100))
                                return 0;
                } else if (chance(399, 400))
                        return 0;
                dbg_rcvry("failing in log LEB %d", lnum);
        } else if (lnum >= c->lpt_first && lnum <= c->lpt_last) {
                if (write) {
                        if (chance(7, 8))
                                return 0;
                } else if (chance(19, 20))
                        return 0;
                dbg_rcvry("failing in LPT LEB %d", lnum);
        } else if (lnum >= c->orph_first && lnum <= c->orph_last) {
                if (write) {
                        if (chance(1, 2))
                                return 0;
                } else if (chance(9, 10))
                        return 0;
                dbg_rcvry("failing in orphan LEB %d", lnum);
        } else if (lnum == c->ihead_lnum) {
                if (chance(99, 100))
                        return 0;
                dbg_rcvry("failing in index head LEB %d", lnum);
        } else if (c->jheads && lnum == c->jheads[GCHD].wbuf.lnum) {
                if (chance(9, 10))
                        return 0;
                dbg_rcvry("failing in GC head LEB %d", lnum);
        } else if (write && !RB_EMPTY_ROOT(&c->buds) &&
                   !ubifs_search_bud(c, lnum)) {
                if (chance(19, 20))
                        return 0;
                dbg_rcvry("failing in non-bud LEB %d", lnum);
        } else if (c->cmt_state == COMMIT_RUNNING_BACKGROUND ||
                   c->cmt_state == COMMIT_RUNNING_REQUIRED) {
                if (chance(999, 1000))
                        return 0;
                dbg_rcvry("failing in bud LEB %d commit running", lnum);
        } else {
                if (chance(9999, 10000))
                        return 0;
                dbg_rcvry("failing in bud LEB %d commit not running", lnum);
        }
        ubifs_err("*** SETTING FAILURE MODE ON (LEB %d) ***", lnum);
        c->failure_mode = 1;
        dump_stack();
        return 1;
}

static void cut_data(const void *buf, int len)
{
        int flen, i;
        unsigned char *p = (void *)buf;

        flen = (len * (long long)simple_rand()) >> 15;
        for (i = flen; i < len; i++)
                p[i] = 0xff;
}

int dbg_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
                 int len, int check)
{
        if (in_failure_mode(desc))
                return -EIO;
        return ubi_leb_read(desc, lnum, buf, offset, len, check);
}

int dbg_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
                  int offset, int len, int dtype)
{
        int err, failing;

        if (in_failure_mode(desc))
                return -EIO;
        failing = do_fail(desc, lnum, 1);
        if (failing)
                cut_data(buf, len);
        err = ubi_leb_write(desc, lnum, buf, offset, len, dtype);
        if (err)
                return err;
        if (failing)
                return -EIO;
        return 0;
}

int dbg_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
                   int len, int dtype)
{
        int err;

        if (do_fail(desc, lnum, 1))
                return -EIO;
        err = ubi_leb_change(desc, lnum, buf, len, dtype);
        if (err)
                return err;
        if (do_fail(desc, lnum, 1))
                return -EIO;
        return 0;
}

int dbg_leb_erase(struct ubi_volume_desc *desc, int lnum)
{
        int err;

        if (do_fail(desc, lnum, 0))
                return -EIO;
        err = ubi_leb_erase(desc, lnum);
        if (err)
                return err;
        if (do_fail(desc, lnum, 0))
                return -EIO;
        return 0;
}

int dbg_leb_unmap(struct ubi_volume_desc *desc, int lnum)
{
        int err;

        if (do_fail(desc, lnum, 0))
                return -EIO;
        err = ubi_leb_unmap(desc, lnum);
        if (err)
                return err;
        if (do_fail(desc, lnum, 0))
                return -EIO;
        return 0;
}

int dbg_is_mapped(struct ubi_volume_desc *desc, int lnum)
{
        if (in_failure_mode(desc))
                return -EIO;
        return ubi_is_mapped(desc, lnum);
}

int dbg_leb_map(struct ubi_volume_desc *desc, int lnum, int dtype)
{
        int err;

        if (do_fail(desc, lnum, 0))
                return -EIO;
        err = ubi_leb_map(desc, lnum, dtype);
        if (err)
                return err;
        if (do_fail(desc, lnum, 0))
                return -EIO;
        return 0;
}

#endif /* CONFIG_UBIFS_FS_DEBUG */