/*
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* This file is part of UBIFS.
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*
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* Copyright (C) 2006-2008 Nokia Corporation
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* Authors: Adrian Hunter
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* Artem Bityutskiy (Битюцкий Артём)
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*/
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/*
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* This file implements the scan which is a general-purpose function for
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* determining what nodes are in an eraseblock. The scan is used to replay the
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* journal, to do garbage collection. for the TNC in-the-gaps method, and by
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* debugging functions.
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*/
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#ifdef __UBOOT__
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#include <hexdump.h>
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#include <linux/err.h>
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#endif
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#include "ubifs.h"
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/**
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* scan_padding_bytes - scan for padding bytes.
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* @buf: buffer to scan
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* @len: length of buffer
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*
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* This function returns the number of padding bytes on success and
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* %SCANNED_GARBAGE on failure.
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*/
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static int scan_padding_bytes(void *buf, int len)
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{
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int pad_len = 0, max_pad_len = min_t(int, UBIFS_PAD_NODE_SZ, len);
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uint8_t *p = buf;
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dbg_scan("not a node");
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while (pad_len < max_pad_len && *p++ == UBIFS_PADDING_BYTE)
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pad_len += 1;
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if (!pad_len || (pad_len & 7))
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return SCANNED_GARBAGE;
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dbg_scan("%d padding bytes", pad_len);
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return pad_len;
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}
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/**
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* ubifs_scan_a_node - scan for a node or padding.
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* @c: UBIFS file-system description object
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* @buf: buffer to scan
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* @len: length of buffer
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* @lnum: logical eraseblock number
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* @offs: offset within the logical eraseblock
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* @quiet: print no messages
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*
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* This function returns a scanning code to indicate what was scanned.
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*/
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int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len, int lnum,
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int offs, int quiet)
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{
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struct ubifs_ch *ch = buf;
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uint32_t magic;
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magic = le32_to_cpu(ch->magic);
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if (magic == 0xFFFFFFFF) {
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dbg_scan("hit empty space at LEB %d:%d", lnum, offs);
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return SCANNED_EMPTY_SPACE;
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}
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if (magic != UBIFS_NODE_MAGIC)
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return scan_padding_bytes(buf, len);
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if (len < UBIFS_CH_SZ)
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return SCANNED_GARBAGE;
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dbg_scan("scanning %s at LEB %d:%d",
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dbg_ntype(ch->node_type), lnum, offs);
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if (ubifs_check_node(c, buf, lnum, offs, quiet, 1))
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return SCANNED_A_CORRUPT_NODE;
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if (ch->node_type == UBIFS_PAD_NODE) {
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struct ubifs_pad_node *pad = buf;
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int pad_len = le32_to_cpu(pad->pad_len);
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int node_len = le32_to_cpu(ch->len);
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/* Validate the padding node */
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if (pad_len < 0 ||
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offs + node_len + pad_len > c->leb_size) {
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if (!quiet) {
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ubifs_err(c, "bad pad node at LEB %d:%d",
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lnum, offs);
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ubifs_dump_node(c, pad);
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}
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return SCANNED_A_BAD_PAD_NODE;
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}
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/* Make the node pads to 8-byte boundary */
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if ((node_len + pad_len) & 7) {
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if (!quiet)
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ubifs_err(c, "bad padding length %d - %d",
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offs, offs + node_len + pad_len);
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return SCANNED_A_BAD_PAD_NODE;
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}
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dbg_scan("%d bytes padded at LEB %d:%d, offset now %d", pad_len,
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lnum, offs, ALIGN(offs + node_len + pad_len, 8));
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return node_len + pad_len;
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}
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return SCANNED_A_NODE;
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}
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/**
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* ubifs_start_scan - create LEB scanning information at start of scan.
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* @c: UBIFS file-system description object
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* @lnum: logical eraseblock number
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* @offs: offset to start at (usually zero)
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* @sbuf: scan buffer (must be c->leb_size)
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*
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* This function returns the scanned information on success and a negative error
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* code on failure.
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*/
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struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum,
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int offs, void *sbuf)
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{
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struct ubifs_scan_leb *sleb;
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int err;
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dbg_scan("scan LEB %d:%d", lnum, offs);
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sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS);
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if (!sleb)
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return ERR_PTR(-ENOMEM);
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sleb->lnum = lnum;
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INIT_LIST_HEAD(&sleb->nodes);
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sleb->buf = sbuf;
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err = ubifs_leb_read(c, lnum, sbuf + offs, offs, c->leb_size - offs, 0);
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if (err && err != -EBADMSG) {
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ubifs_err(c, "cannot read %d bytes from LEB %d:%d, error %d",
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c->leb_size - offs, lnum, offs, err);
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kfree(sleb);
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return ERR_PTR(err);
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}
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/*
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* Note, we ignore integrity errors (EBASMSG) because all the nodes are
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* protected by CRC checksums.
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*/
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return sleb;
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}
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/**
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* ubifs_end_scan - update LEB scanning information at end of scan.
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* @c: UBIFS file-system description object
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* @sleb: scanning information
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* @lnum: logical eraseblock number
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* @offs: offset to start at (usually zero)
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*/
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void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
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int lnum, int offs)
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{
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lnum = lnum;
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dbg_scan("stop scanning LEB %d at offset %d", lnum, offs);
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ubifs_assert(offs % c->min_io_size == 0);
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sleb->endpt = ALIGN(offs, c->min_io_size);
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}
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/**
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* ubifs_add_snod - add a scanned node to LEB scanning information.
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* @c: UBIFS file-system description object
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* @sleb: scanning information
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* @buf: buffer containing node
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* @offs: offset of node on flash
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*
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* This function returns %0 on success and a negative error code on failure.
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*/
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int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
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void *buf, int offs)
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{
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struct ubifs_ch *ch = buf;
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struct ubifs_ino_node *ino = buf;
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struct ubifs_scan_node *snod;
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snod = kmalloc(sizeof(struct ubifs_scan_node), GFP_NOFS);
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if (!snod)
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return -ENOMEM;
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snod->sqnum = le64_to_cpu(ch->sqnum);
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snod->type = ch->node_type;
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snod->offs = offs;
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snod->len = le32_to_cpu(ch->len);
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snod->node = buf;
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switch (ch->node_type) {
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case UBIFS_INO_NODE:
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case UBIFS_DENT_NODE:
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case UBIFS_XENT_NODE:
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case UBIFS_DATA_NODE:
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/*
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* The key is in the same place in all keyed
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* nodes.
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*/
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key_read(c, &ino->key, &snod->key);
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break;
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default:
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invalid_key_init(c, &snod->key);
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break;
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}
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list_add_tail(&snod->list, &sleb->nodes);
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sleb->nodes_cnt += 1;
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return 0;
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}
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/**
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* ubifs_scanned_corruption - print information after UBIFS scanned corruption.
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* @c: UBIFS file-system description object
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* @lnum: LEB number of corruption
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* @offs: offset of corruption
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* @buf: buffer containing corruption
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*/
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void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,
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void *buf)
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{
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int len;
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ubifs_err(c, "corruption at LEB %d:%d", lnum, offs);
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len = c->leb_size - offs;
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if (len > 8192)
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len = 8192;
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ubifs_err(c, "first %d bytes from LEB %d:%d", len, lnum, offs);
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print_hex_dump("", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1);
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}
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/**
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* ubifs_scan - scan a logical eraseblock.
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* @c: UBIFS file-system description object
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* @lnum: logical eraseblock number
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* @offs: offset to start at (usually zero)
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* @sbuf: scan buffer (must be of @c->leb_size bytes in size)
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* @quiet: print no messages
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*
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* This function scans LEB number @lnum and returns complete information about
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* its contents. Returns the scanned information in case of success and,
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* %-EUCLEAN if the LEB neads recovery, and other negative error codes in case
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* of failure.
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*
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* If @quiet is non-zero, this function does not print large and scary
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* error messages and flash dumps in case of errors.
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*/
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struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
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int offs, void *sbuf, int quiet)
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{
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void *buf = sbuf + offs;
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int err, len = c->leb_size - offs;
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struct ubifs_scan_leb *sleb;
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sleb = ubifs_start_scan(c, lnum, offs, sbuf);
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if (IS_ERR(sleb))
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return sleb;
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while (len >= 8) {
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struct ubifs_ch *ch = buf;
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int node_len, ret;
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dbg_scan("look at LEB %d:%d (%d bytes left)",
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lnum, offs, len);
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cond_resched();
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ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
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if (ret > 0) {
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/* Padding bytes or a valid padding node */
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offs += ret;
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buf += ret;
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len -= ret;
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continue;
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}
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if (ret == SCANNED_EMPTY_SPACE)
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/* Empty space is checked later */
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break;
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switch (ret) {
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case SCANNED_GARBAGE:
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ubifs_err(c, "garbage");
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goto corrupted;
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case SCANNED_A_NODE:
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break;
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case SCANNED_A_CORRUPT_NODE:
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case SCANNED_A_BAD_PAD_NODE:
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ubifs_err(c, "bad node");
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goto corrupted;
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default:
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ubifs_err(c, "unknown");
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err = -EINVAL;
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goto error;
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}
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err = ubifs_add_snod(c, sleb, buf, offs);
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if (err)
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goto error;
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node_len = ALIGN(le32_to_cpu(ch->len), 8);
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offs += node_len;
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buf += node_len;
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len -= node_len;
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}
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if (offs % c->min_io_size) {
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if (!quiet)
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ubifs_err(c, "empty space starts at non-aligned offset %d",
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offs);
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goto corrupted;
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}
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ubifs_end_scan(c, sleb, lnum, offs);
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for (; len > 4; offs += 4, buf = buf + 4, len -= 4)
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if (*(uint32_t *)buf != 0xffffffff)
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break;
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for (; len; offs++, buf++, len--)
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if (*(uint8_t *)buf != 0xff) {
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if (!quiet)
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ubifs_err(c, "corrupt empty space at LEB %d:%d",
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lnum, offs);
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goto corrupted;
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}
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return sleb;
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corrupted:
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if (!quiet) {
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ubifs_scanned_corruption(c, lnum, offs, buf);
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ubifs_err(c, "LEB %d scanning failed", lnum);
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}
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err = -EUCLEAN;
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ubifs_scan_destroy(sleb);
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return ERR_PTR(err);
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error:
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ubifs_err(c, "LEB %d scanning failed, error %d", lnum, err);
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ubifs_scan_destroy(sleb);
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return ERR_PTR(err);
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}
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/**
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* ubifs_scan_destroy - destroy LEB scanning information.
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* @sleb: scanning information to free
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*/
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void ubifs_scan_destroy(struct ubifs_scan_leb *sleb)
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{
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struct ubifs_scan_node *node;
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struct list_head *head;
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head = &sleb->nodes;
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while (!list_empty(head)) {
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node = list_entry(head->next, struct ubifs_scan_node, list);
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list_del(&node->list);
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kfree(node);
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}
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kfree(sleb);
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}
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