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- /*
- * This file is part of UBIFS.
- *
- * Copyright (C) 2006-2008 Nokia Corporation
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 51
- * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * Authors: Adrian Hunter
- * Artem Bityutskiy (Битюцкий Артём)
- */
- /*
- * This file implements the scan which is a general-purpose function for
- * determining what nodes are in an eraseblock. The scan is used to replay the
- * journal, to do garbage collection. for the TNC in-the-gaps method, and by
- * debugging functions.
- */
- #include "ubifs.h"
- /**
- * scan_padding_bytes - scan for padding bytes.
- * @buf: buffer to scan
- * @len: length of buffer
- *
- * This function returns the number of padding bytes on success and
- * %SCANNED_GARBAGE on failure.
- */
- static int scan_padding_bytes(void *buf, int len)
- {
- int pad_len = 0, max_pad_len = min_t(int, UBIFS_PAD_NODE_SZ, len);
- uint8_t *p = buf;
- dbg_scan("not a node");
- while (pad_len < max_pad_len && *p++ == UBIFS_PADDING_BYTE)
- pad_len += 1;
- if (!pad_len || (pad_len & 7))
- return SCANNED_GARBAGE;
- dbg_scan("%d padding bytes", pad_len);
- return pad_len;
- }
- /**
- * ubifs_scan_a_node - scan for a node or padding.
- * @c: UBIFS file-system description object
- * @buf: buffer to scan
- * @len: length of buffer
- * @lnum: logical eraseblock number
- * @offs: offset within the logical eraseblock
- * @quiet: print no messages
- *
- * This function returns a scanning code to indicate what was scanned.
- */
- int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len, int lnum,
- int offs, int quiet)
- {
- struct ubifs_ch *ch = buf;
- uint32_t magic;
- magic = le32_to_cpu(ch->magic);
- if (magic == 0xFFFFFFFF) {
- dbg_scan("hit empty space at LEB %d:%d", lnum, offs);
- return SCANNED_EMPTY_SPACE;
- }
- if (magic != UBIFS_NODE_MAGIC)
- return scan_padding_bytes(buf, len);
- if (len < UBIFS_CH_SZ)
- return SCANNED_GARBAGE;
- dbg_scan("scanning %s at LEB %d:%d",
- dbg_ntype(ch->node_type), lnum, offs);
- if (ubifs_check_node(c, buf, lnum, offs, quiet, 1))
- return SCANNED_A_CORRUPT_NODE;
- if (ch->node_type == UBIFS_PAD_NODE) {
- struct ubifs_pad_node *pad = buf;
- int pad_len = le32_to_cpu(pad->pad_len);
- int node_len = le32_to_cpu(ch->len);
- /* Validate the padding node */
- if (pad_len < 0 ||
- offs + node_len + pad_len > c->leb_size) {
- if (!quiet) {
- ubifs_err(c, "bad pad node at LEB %d:%d",
- lnum, offs);
- ubifs_dump_node(c, pad);
- }
- return SCANNED_A_BAD_PAD_NODE;
- }
- /* Make the node pads to 8-byte boundary */
- if ((node_len + pad_len) & 7) {
- if (!quiet)
- ubifs_err(c, "bad padding length %d - %d",
- offs, offs + node_len + pad_len);
- return SCANNED_A_BAD_PAD_NODE;
- }
- dbg_scan("%d bytes padded at LEB %d:%d, offset now %d", pad_len,
- lnum, offs, ALIGN(offs + node_len + pad_len, 8));
- return node_len + pad_len;
- }
- return SCANNED_A_NODE;
- }
- /**
- * ubifs_start_scan - create LEB scanning information at start of scan.
- * @c: UBIFS file-system description object
- * @lnum: logical eraseblock number
- * @offs: offset to start at (usually zero)
- * @sbuf: scan buffer (must be c->leb_size)
- *
- * This function returns the scanned information on success and a negative error
- * code on failure.
- */
- struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum,
- int offs, void *sbuf)
- {
- struct ubifs_scan_leb *sleb;
- int err;
- dbg_scan("scan LEB %d:%d", lnum, offs);
- sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS);
- if (!sleb)
- return ERR_PTR(-ENOMEM);
- sleb->lnum = lnum;
- INIT_LIST_HEAD(&sleb->nodes);
- sleb->buf = sbuf;
- err = ubifs_leb_read(c, lnum, sbuf + offs, offs, c->leb_size - offs, 0);
- if (err && err != -EBADMSG) {
- ubifs_err(c, "cannot read %d bytes from LEB %d:%d, error %d",
- c->leb_size - offs, lnum, offs, err);
- kfree(sleb);
- return ERR_PTR(err);
- }
- /*
- * Note, we ignore integrity errors (EBASMSG) because all the nodes are
- * protected by CRC checksums.
- */
- return sleb;
- }
- /**
- * ubifs_end_scan - update LEB scanning information at end of scan.
- * @c: UBIFS file-system description object
- * @sleb: scanning information
- * @lnum: logical eraseblock number
- * @offs: offset to start at (usually zero)
- */
- void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
- int lnum, int offs)
- {
- lnum = lnum;
- dbg_scan("stop scanning LEB %d at offset %d", lnum, offs);
- ubifs_assert(offs % c->min_io_size == 0);
- sleb->endpt = ALIGN(offs, c->min_io_size);
- }
- /**
- * ubifs_add_snod - add a scanned node to LEB scanning information.
- * @c: UBIFS file-system description object
- * @sleb: scanning information
- * @buf: buffer containing node
- * @offs: offset of node on flash
- *
- * This function returns %0 on success and a negative error code on failure.
- */
- int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
- void *buf, int offs)
- {
- struct ubifs_ch *ch = buf;
- struct ubifs_ino_node *ino = buf;
- struct ubifs_scan_node *snod;
- snod = kmalloc(sizeof(struct ubifs_scan_node), GFP_NOFS);
- if (!snod)
- return -ENOMEM;
- snod->sqnum = le64_to_cpu(ch->sqnum);
- snod->type = ch->node_type;
- snod->offs = offs;
- snod->len = le32_to_cpu(ch->len);
- snod->node = buf;
- switch (ch->node_type) {
- case UBIFS_INO_NODE:
- case UBIFS_DENT_NODE:
- case UBIFS_XENT_NODE:
- case UBIFS_DATA_NODE:
- /*
- * The key is in the same place in all keyed
- * nodes.
- */
- key_read(c, &ino->key, &snod->key);
- break;
- default:
- invalid_key_init(c, &snod->key);
- break;
- }
- list_add_tail(&snod->list, &sleb->nodes);
- sleb->nodes_cnt += 1;
- return 0;
- }
- /**
- * ubifs_scanned_corruption - print information after UBIFS scanned corruption.
- * @c: UBIFS file-system description object
- * @lnum: LEB number of corruption
- * @offs: offset of corruption
- * @buf: buffer containing corruption
- */
- void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,
- void *buf)
- {
- int len;
- ubifs_err(c, "corruption at LEB %d:%d", lnum, offs);
- len = c->leb_size - offs;
- if (len > 8192)
- len = 8192;
- ubifs_err(c, "first %d bytes from LEB %d:%d", len, lnum, offs);
- print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1);
- }
- /**
- * ubifs_scan - scan a logical eraseblock.
- * @c: UBIFS file-system description object
- * @lnum: logical eraseblock number
- * @offs: offset to start at (usually zero)
- * @sbuf: scan buffer (must be of @c->leb_size bytes in size)
- * @quiet: print no messages
- *
- * This function scans LEB number @lnum and returns complete information about
- * its contents. Returns the scanned information in case of success and,
- * %-EUCLEAN if the LEB neads recovery, and other negative error codes in case
- * of failure.
- *
- * If @quiet is non-zero, this function does not print large and scary
- * error messages and flash dumps in case of errors.
- */
- struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
- int offs, void *sbuf, int quiet)
- {
- void *buf = sbuf + offs;
- int err, len = c->leb_size - offs;
- struct ubifs_scan_leb *sleb;
- sleb = ubifs_start_scan(c, lnum, offs, sbuf);
- if (IS_ERR(sleb))
- return sleb;
- while (len >= 8) {
- struct ubifs_ch *ch = buf;
- int node_len, ret;
- dbg_scan("look at LEB %d:%d (%d bytes left)",
- lnum, offs, len);
- cond_resched();
- ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
- if (ret > 0) {
- /* Padding bytes or a valid padding node */
- offs += ret;
- buf += ret;
- len -= ret;
- continue;
- }
- if (ret == SCANNED_EMPTY_SPACE)
- /* Empty space is checked later */
- break;
- switch (ret) {
- case SCANNED_GARBAGE:
- ubifs_err(c, "garbage");
- goto corrupted;
- case SCANNED_A_NODE:
- break;
- case SCANNED_A_CORRUPT_NODE:
- case SCANNED_A_BAD_PAD_NODE:
- ubifs_err(c, "bad node");
- goto corrupted;
- default:
- ubifs_err(c, "unknown");
- err = -EINVAL;
- goto error;
- }
- err = ubifs_add_snod(c, sleb, buf, offs);
- if (err)
- goto error;
- node_len = ALIGN(le32_to_cpu(ch->len), 8);
- offs += node_len;
- buf += node_len;
- len -= node_len;
- }
- if (offs % c->min_io_size) {
- if (!quiet)
- ubifs_err(c, "empty space starts at non-aligned offset %d",
- offs);
- goto corrupted;
- }
- ubifs_end_scan(c, sleb, lnum, offs);
- for (; len > 4; offs += 4, buf = buf + 4, len -= 4)
- if (*(uint32_t *)buf != 0xffffffff)
- break;
- for (; len; offs++, buf++, len--)
- if (*(uint8_t *)buf != 0xff) {
- if (!quiet)
- ubifs_err(c, "corrupt empty space at LEB %d:%d",
- lnum, offs);
- goto corrupted;
- }
- return sleb;
- corrupted:
- if (!quiet) {
- ubifs_scanned_corruption(c, lnum, offs, buf);
- ubifs_err(c, "LEB %d scanning failed", lnum);
- }
- err = -EUCLEAN;
- ubifs_scan_destroy(sleb);
- return ERR_PTR(err);
- error:
- ubifs_err(c, "LEB %d scanning failed, error %d", lnum, err);
- ubifs_scan_destroy(sleb);
- return ERR_PTR(err);
- }
- /**
- * ubifs_scan_destroy - destroy LEB scanning information.
- * @sleb: scanning information to free
- */
- void ubifs_scan_destroy(struct ubifs_scan_leb *sleb)
- {
- struct ubifs_scan_node *node;
- struct list_head *head;
- head = &sleb->nodes;
- while (!list_empty(head)) {
- node = list_entry(head->next, struct ubifs_scan_node, list);
- list_del(&node->list);
- kfree(node);
- }
- kfree(sleb);
- }
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