/*
* This file is part of UBIFS.
*
* Copyright (C) 2006-2008 Nokia Corporation.
* Copyright (C) 2006, 2007 University of Szeged, Hungary
*
* 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
* Zoltan Sogor
*/
/*
* This file implements UBIFS I/O subsystem which provides various I/O-related
* helper functions (reading/writing/checking/validating nodes) and implements
* write-buffering support. Write buffers help to save space which otherwise
* would have been wasted for padding to the nearest minimal I/O unit boundary.
* Instead, data first goes to the write-buffer and is flushed when the
* buffer is full or when it is not used for some time (by timer). This is
* similar to the mechanism is used by JFFS2.
*
* UBIFS distinguishes between minimum write size (@c->min_io_size) and maximum
* write size (@c->max_write_size). The latter is the maximum amount of bytes
* the underlying flash is able to program at a time, and writing in
* @c->max_write_size units should presumably be faster. Obviously,
* @c->min_io_size <= @c->max_write_size. Write-buffers are of
* @c->max_write_size bytes in size for maximum performance. However, when a
* write-buffer is flushed, only the portion of it (aligned to @c->min_io_size
* boundary) which contains data is written, not the whole write-buffer,
* because this is more space-efficient.
*
* This optimization adds few complications to the code. Indeed, on the one
* hand, we want to write in optimal @c->max_write_size bytes chunks, which
* also means aligning writes at the @c->max_write_size bytes offsets. On the
* other hand, we do not want to waste space when synchronizing the write
* buffer, so during synchronization we writes in smaller chunks. And this makes
* the next write offset to be not aligned to @c->max_write_size bytes. So the
* have to make sure that the write-buffer offset (@wbuf->offs) becomes aligned
* to @c->max_write_size bytes again. We do this by temporarily shrinking
* write-buffer size (@wbuf->size).
*
* Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by
* mutexes defined inside these objects. Since sometimes upper-level code
* has to lock the write-buffer (e.g. journal space reservation code), many
* functions related to write-buffers have "nolock" suffix which means that the
* caller has to lock the write-buffer before calling this function.
*
* UBIFS stores nodes at 64 bit-aligned addresses. If the node length is not
* aligned, UBIFS starts the next node from the aligned address, and the padded
* bytes may contain any rubbish. In other words, UBIFS does not put padding
* bytes in those small gaps. Common headers of nodes store real node lengths,
* not aligned lengths. Indexing nodes also store real lengths in branches.
*
* UBIFS uses padding when it pads to the next min. I/O unit. In this case it
* uses padding nodes or padding bytes, if the padding node does not fit.
*
* All UBIFS nodes are protected by CRC checksums and UBIFS checks CRC when
* they are read from the flash media.
*/
#include <linux/err.h>
#include "ubifs.h"
/**
* ubifs_ro_mode - switch UBIFS to read read-only mode.
* @c: UBIFS file-system description object
* @err: error code which is the reason of switching to R/O mode
*/
void ubifs_ro_mode(struct ubifs_info *c, int err)
{
if (!c->ro_error) {
c->ro_error = 1;
c->no_chk_data_crc = 0;
c->vfs_sb->s_flags |= SB_RDONLY;
ubifs_warn(c, "switched to read-only mode, error %d", err);
dump_stack();
}
}
/*
* Below are simple wrappers over UBI I/O functions which include some
* additional checks and UBIFS debugging stuff. See corresponding UBI function
* for more information.
*/
int ubifs_leb_read(const struct ubifs_info *c, int lnum, void *buf, int offs,
int len, int even_ebadmsg)
{
int err;
err = ubi_read(c->ubi, lnum, buf, offs, len);
/*
* In case of %-EBADMSG print the error message only if the
* @even_ebadmsg is true.
*/
if (err && (err != -EBADMSG || even_ebadmsg)) {
ubifs_err(c, "reading %d bytes from LEB %d:%d failed, error %d",
len, lnum, offs, err);
dump_stack();
}
return err;
}
/*
* removed in barebox
int ubifs_leb_write(struct ubifs_info *c, int lnum, const void *buf, int offs,
int len)
*/
/*
* removed in barebox
int ubifs_leb_change(struct ubifs_info *c, int lnum, const void *buf, int len)
*/
/*
* removed in barebox
int ubifs_leb_unmap(struct ubifs_info *c, int lnum)
*/
/*
* removed in barebox
int ubifs_leb_map(struct ubifs_info *c, int lnum)
*/
int ubifs_is_mapped(const struct ubifs_info *c, int lnum)
{
int err;
err = ubi_is_mapped(c->ubi, lnum);
if (err < 0) {
ubifs_err(c, "ubi_is_mapped failed for LEB %d, error %d",
lnum, err);
dump_stack();
}
return err;
}
/**
* ubifs_check_node - check node.
* @c: UBIFS file-system description object
* @buf: node to check
* @lnum: logical eraseblock number
* @offs: offset within the logical eraseblock
* @quiet: print no messages
* @must_chk_crc: indicates whether to always check the CRC
*
* This function checks node magic number and CRC checksum. This function also
* validates node length to prevent UBIFS from becoming crazy when an attacker
* feeds it a file-system image with incorrect nodes. For example, too large
* node length in the common header could cause UBIFS to read memory outside of
* allocated buffer when checking the CRC checksum.
*
* This function may skip data nodes CRC checking if @c->no_chk_data_crc is
* true, which is controlled by corresponding UBIFS mount option. However, if
* @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is
* checked. Similarly, if @c->mounting or @c->remounting_rw is true (we are
* mounting or re-mounting to R/W mode), @c->no_chk_data_crc is ignored and CRC
* is checked. This is because during mounting or re-mounting from R/O mode to
* R/W mode we may read journal nodes (when replying the journal or doing the
* recovery) and the journal nodes may potentially be corrupted, so checking is
* required.
*
* This function returns zero in case of success and %-EUCLEAN in case of bad
* CRC or magic.
*/
int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
int offs, int quiet, int must_chk_crc)
{
int err = -EINVAL, type, node_len;
uint32_t crc, node_crc, magic;
const struct ubifs_ch *ch = buf;
ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
ubifs_assert(c, !(offs & 7) && offs < c->leb_size);
magic = le32_to_cpu(ch->magic);
if (magic != UBIFS_NODE_MAGIC) {
if (!quiet)
ubifs_err(c, "bad magic %#08x, expected %#08x",
magic, UBIFS_NODE_MAGIC);
err = -EUCLEAN;
goto out;
}
type = ch->node_type;
if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) {
if (!quiet)
ubifs_err(c, "bad node type %d", type);
goto out;
}
node_len = le32_to_cpu(ch->len);
if (node_len + offs > c->leb_size)
goto out_len;
if (c->ranges[type].max_len == 0) {
if (node_len != c->ranges[type].len)
goto out_len;
} else if (node_len < c->ranges[type].min_len ||
node_len > c->ranges[type].max_len)
goto out_len;
if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->mounting &&
!c->remounting_rw && c->no_chk_data_crc)
return 0;
crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
node_crc = le32_to_cpu(ch->crc);
if (crc != node_crc) {
if (!quiet)
ubifs_err(c, "bad CRC: calculated %#08x, read %#08x",
crc, node_crc);
err = -EUCLEAN;
goto out;
}
return 0;
out_len:
if (!quiet)
ubifs_err(c, "bad node length %d", node_len);
out:
if (!quiet) {
ubifs_err(c, "bad node at LEB %d:%d", lnum, offs);
ubifs_dump_node(c, buf);
dump_stack();
}
return err;
}
/**
* ubifs_pad - pad flash space.
* @c: UBIFS file-system description object
* @buf: buffer to put padding to
* @pad: how many bytes to pad
*
* The flash media obliges us to write only in chunks of %c->min_io_size and
* when we have to write less data we add padding node to the write-buffer and
* pad it to the next minimal I/O unit's boundary. Padding nodes help when the
* media is being scanned. If the amount of wasted space is not enough to fit a
* padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes
* pattern (%UBIFS_PADDING_BYTE).
*
* Padding nodes are also used to fill gaps when the "commit-in-gaps" method is
* used.
*/
void ubifs_pad(const struct ubifs_info *c, void *buf, int pad)
{
uint32_t crc;
ubifs_assert(c, pad >= 0 && !(pad & 7));
if (pad >= UBIFS_PAD_NODE_SZ) {
struct ubifs_ch *ch = buf;
struct ubifs_pad_node *pad_node = buf;
ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
ch->node_type = UBIFS_PAD_NODE;
ch->group_type = UBIFS_NO_NODE_GROUP;
ch->padding[0] = ch->padding[1] = 0;
ch->sqnum = 0;
ch->len = cpu_to_le32(UBIFS_PAD_NODE_SZ);
pad -= UBIFS_PAD_NODE_SZ;
pad_node->pad_len = cpu_to_le32(pad);
crc = crc32(UBIFS_CRC32_INIT, buf + 8, UBIFS_PAD_NODE_SZ - 8);
ch->crc = cpu_to_le32(crc);
memset(buf + UBIFS_PAD_NODE_SZ, 0, pad);
} else if (pad > 0)
/* Too little space, padding node won't fit */
memset(buf, UBIFS_PADDING_BYTE, pad);
}
/*
* removed in barebox
static unsigned long long next_sqnum(struct ubifs_info *c)
*/
/*
* removed in barebox
void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad)
*/
/*
* removed in barebox
void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last)
*/
/*
* removed in barebox
static enum hrtimer_restart wbuf_timer_callback_nolock(struct hrtimer *timer)
*/
/*
* removed in barebox
static void new_wbuf_timer_nolock(struct ubifs_info *c, struct ubifs_wbuf *wbuf)
*/
/*
* removed in barebox
static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
*/
/*
* removed in barebox
int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf)
*/
/*
* removed in barebox
int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs)
*/
/*
* removed in barebox
int ubifs_bg_wbufs_sync(struct ubifs_info *c)
*/
/*
* removed in barebox
int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len)
*/
/*
* removed in barebox
int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
int offs)
*/
/*
* removed in barebox
int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
int lnum, int offs)
*/
/**
* ubifs_read_node - read node.
* @c: UBIFS file-system description object
* @buf: buffer to read to
* @type: node type
* @len: node length (not aligned)
* @lnum: logical eraseblock number
* @offs: offset within the logical eraseblock
*
* This function reads a node of known type and and length, checks it and
* stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
* and a negative error code in case of failure.
*/
int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
int lnum, int offs)
{
int err, l;
struct ubifs_ch *ch = buf;
dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
ubifs_assert(c, len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
ubifs_assert(c, !(offs & 7) && offs < c->leb_size);
ubifs_assert(c, type >= 0 && type < UBIFS_NODE_TYPES_CNT);
err = ubifs_leb_read(c, lnum, buf, offs, len, 0);
if (err && err != -EBADMSG)
return err;
if (type != ch->node_type) {
ubifs_errc(c, "bad node type (%d but expected %d)",
ch->node_type, type);
goto out;
}
err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
if (err) {
ubifs_errc(c, "expected node type %d", type);
return err;
}
l = le32_to_cpu(ch->len);
if (l != len) {
ubifs_errc(c, "bad node length %d, expected %d", l, len);
goto out;
}
return 0;
out:
ubifs_errc(c, "bad node at LEB %d:%d, LEB mapping status %d", lnum,
offs, ubi_is_mapped(c->ubi, lnum));
if (!c->probing) {
ubifs_dump_node(c, buf);
dump_stack();
}
return -EINVAL;
}
/**
* ubifs_wbuf_init - initialize write-buffer.
* @c: UBIFS file-system description object
* @wbuf: write-buffer to initialize
*
* This function initializes write-buffer. Returns zero in case of success
* %-ENOMEM in case of failure.
*/
int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf)
{
size_t size;
wbuf->buf = kmalloc(c->max_write_size, GFP_KERNEL);
if (!wbuf->buf)
return -ENOMEM;
size = (c->max_write_size / UBIFS_CH_SZ + 1) * sizeof(ino_t);
wbuf->inodes = kmalloc(size, GFP_KERNEL);
if (!wbuf->inodes) {
kfree(wbuf->buf);
wbuf->buf = NULL;
return -ENOMEM;
}
wbuf->used = 0;
wbuf->lnum = wbuf->offs = -1;
/*
* If the LEB starts at the max. write size aligned address, then
* write-buffer size has to be set to @c->max_write_size. Otherwise,
* set it to something smaller so that it ends at the closest max.
* write size boundary.
*/
size = c->max_write_size - (c->leb_start % c->max_write_size);
wbuf->avail = wbuf->size = size;
wbuf->sync_callback = NULL;
mutex_init(&wbuf->io_mutex);
spin_lock_init(&wbuf->lock);
wbuf->c = c;
wbuf->next_ino = 0;
/* hrtimer not needed in barebox */
return 0;
}
/*
* removed in barebox
void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum)
*/
/*
* removed in barebox
static int wbuf_has_ino(struct ubifs_wbuf *wbuf, ino_t inum)
*/
/*
* removed in barebox
int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode)
*/
