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linux-next/fs/ubifs/scan.c
Artem Bityutskiy 348709bad3 UBIFS: do not print scary error messages needlessly
At the moment UBIFS print large and scary error messages and
flash dumps in case of nearly any corruption, even if it is
a recoverable corruption. For example, if the master node is
corrupted, ubifs_scan() prints error dumps, then UBIFS recovers
just fine and goes on.

This patch makes UBIFS print scary error messages only in
real cases, which are not recoverable. It adds 'quiet' argument
to the 'ubifs_scan()' function, so the caller may ask 'ubi_scan()'
not to print error messages if the caller is able to do recovery.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reviewed-by: Adrian Hunter <Adrian.Hunter@nokia.com>
2009-09-10 12:06:47 +03:00

379 lines
9.4 KiB
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: 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");
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", dbg_ntype(ch->node_type));
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("bad pad node at LEB %d:%d",
lnum, offs);
dbg_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)
dbg_err("bad padding length %d - %d",
offs, offs + node_len + pad_len);
return SCANNED_A_BAD_PAD_NODE;
}
dbg_scan("%d bytes padded, offset now %d",
pad_len, 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 %0 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 = ubi_read(c->ubi, lnum, sbuf + offs, offs, c->leb_size - offs);
if (err && err != -EBADMSG) {
ubifs_err("cannot read %d bytes from LEB %d:%d,"
" error %d", c->leb_size - offs, lnum, offs, err);
kfree(sleb);
return ERR_PTR(err);
}
if (err == -EBADMSG)
sleb->ecc = 1;
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)
*
* This function returns %0 on success and a negative error code on failure.
*/
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 = kzalloc(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:
case UBIFS_TRUN_NODE:
/*
* The key is in the same place in all keyed
* nodes.
*/
key_read(c, &ino->key, &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("corruption at LEB %d:%d", lnum, offs);
if (dbg_failure_mode)
return;
len = c->leb_size - offs;
if (len > 8192)
len = 8192;
dbg_err("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 scaned 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:
dbg_err("garbage");
goto corrupted;
case SCANNED_A_NODE:
break;
case SCANNED_A_CORRUPT_NODE:
case SCANNED_A_BAD_PAD_NODE:
dbg_err("bad node");
goto corrupted;
default:
dbg_err("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("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("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("LEB %d scanning failed", lnum);
}
err = -EUCLEAN;
ubifs_scan_destroy(sleb);
return ERR_PTR(err);
error:
ubifs_err("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);
}