/*
* Copyright (c) International Business Machines Corp., 2006
* Copyright (c) Nokia Corporation, 2006
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Artem Bityutskiy (Битюцкий Артём)
*
* Jan 2007: Alexander Schmidt, hacked per-volume update.
*/
/*
* This file contains implementation of the volume update functionality.
*
* The update operation is based on the per-volume update marker which is
* stored in the volume table. The update marker is set before the update
* starts, and removed after the update has been finished. So if the update was
* interrupted by an unclean re-boot or due to some other reasons, the update
* marker stays on the flash media and UBI finds it when it attaches the MTD
* device next time. If the update marker is set for a volume, the volume is
* treated as damaged and most I/O operations are prohibited. Only a new update
* operation is allowed.
*
* Note, in general it is possible to implement the update operation as a
* transaction with a roll-back capability.
*/
#include <linux/err.h>
#include <asm/uaccess.h>
#include <asm/div64.h>
#include "ubi.h"
/**
* set_update_marker - set update marker.
* @ubi: UBI device description object
* @vol_id: volume ID
*
* This function sets the update marker flag for volume @vol_id. Returns zero
* in case of success and a negative error code in case of failure.
*/
static int set_update_marker(struct ubi_device *ubi, int vol_id)
{
int err;
struct ubi_vtbl_record vtbl_rec;
struct ubi_volume *vol = ubi->volumes[vol_id];
dbg_msg("set update marker for volume %d", vol_id);
if (vol->upd_marker) {
ubi_assert(ubi->vtbl[vol_id].upd_marker);
dbg_msg("already set");
return 0;
}
memcpy(&vtbl_rec, &ubi->vtbl[vol_id], sizeof(struct ubi_vtbl_record));
vtbl_rec.upd_marker = 1;
err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
vol->upd_marker = 1;
return err;
}
/**
* clear_update_marker - clear update marker.
* @ubi: UBI device description object
* @vol_id: volume ID
* @bytes: new data size in bytes
*
* This function clears the update marker for volume @vol_id, sets new volume
* data size and clears the "corrupted" flag (static volumes only). Returns
* zero in case of success and a negative error code in case of failure.
*/
static int clear_update_marker(struct ubi_device *ubi, int vol_id, long long bytes)
{
int err;
uint64_t tmp;
struct ubi_vtbl_record vtbl_rec;
struct ubi_volume *vol = ubi->volumes[vol_id];
dbg_msg("clear update marker for volume %d", vol_id);
memcpy(&vtbl_rec, &ubi->vtbl[vol_id], sizeof(struct ubi_vtbl_record));
ubi_assert(vol->upd_marker && vtbl_rec.upd_marker);
vtbl_rec.upd_marker = 0;
if (vol->vol_type == UBI_STATIC_VOLUME) {
vol->corrupted = 0;
vol->used_bytes = tmp = bytes;
vol->last_eb_bytes = do_div(tmp, vol->usable_leb_size);
vol->used_ebs = tmp;
if (vol->last_eb_bytes)
vol->used_ebs += 1;
else
vol->last_eb_bytes = vol->usable_leb_size;
}
err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
vol->upd_marker = 0;
return err;
}
/**
* ubi_start_update - start volume update.
* @ubi: UBI device description object
* @vol_id: volume ID
* @bytes: update bytes
*
* This function starts volume update operation. If @bytes is zero, the volume
* is just wiped out. Returns zero in case of success and a negative error code
* in case of failure.
*/
int ubi_start_update(struct ubi_device *ubi, int vol_id, long long bytes)
{
int i, err;
uint64_t tmp;
struct ubi_volume *vol = ubi->volumes[vol_id];
dbg_msg("start update of volume %d, %llu bytes", vol_id, bytes);
vol->updating = 1;
err = set_update_marker(ubi, vol_id);
if (err)
return err;
/* Before updating - wipe out the volume */
for (i = 0; i < vol->reserved_pebs; i++) {
err = ubi_eba_unmap_leb(ubi, vol_id, i);
if (err)
return err;
}
if (bytes == 0) {
err = clear_update_marker(ubi, vol_id, 0);
if (err)
return err;
err = ubi_wl_flush(ubi);
if (!err)
vol->updating = 0;
}
vol->upd_buf = kmalloc(ubi->leb_size, GFP_KERNEL);
if (!vol->upd_buf)
return -ENOMEM;
tmp = bytes;
vol->upd_ebs = !!do_div(tmp, vol->usable_leb_size);
vol->upd_ebs += tmp;
vol->upd_bytes = bytes;
vol->upd_received = 0;
return 0;
}
/**
* write_leb - write update data.
* @ubi: UBI device description object
* @vol_id: volume ID
* @lnum: logical eraseblock number
* @buf: data to write
* @len: data size
* @used_ebs: how many logical eraseblocks will this volume contain (static
* volumes only)
*
* This function writes update data to corresponding logical eraseblock. In
* case of dynamic volume, this function checks if the data contains 0xFF bytes
* at the end. If yes, the 0xFF bytes are cut and not written. So if the whole
* buffer contains only 0xFF bytes, the LEB is left unmapped.
*
* The reason why we skip the trailing 0xFF bytes in case of dynamic volume is
* that we want to make sure that more data may be appended to the logical
* eraseblock in future. Indeed, writing 0xFF bytes may have side effects and
* this PEB won't be writable anymore. So if one writes the file-system image
* to the UBI volume where 0xFFs mean free space - UBI makes sure this free
* space is writable after the update.
*
* We do not do this for static volumes because they are read-only. But this
* also cannot be done because we have to store per-LEB CRC and the correct
* data length.
*
* This function returns zero in case of success and a negative error code in
* case of failure.
*/
static int write_leb(struct ubi_device *ubi, int vol_id, int lnum, void *buf,
int len, int used_ebs)
{
int err, l;
struct ubi_volume *vol = ubi->volumes[vol_id];
if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
l = ALIGN(len, ubi->min_io_size);
memset(buf + len, 0xFF, l - len);
l = ubi_calc_data_len(ubi, buf, l);
if (l == 0) {
dbg_msg("all %d bytes contain 0xFF - skip", len);
return 0;
}
if (len != l)
dbg_msg("skip last %d bytes (0xFF)", len - l);
err = ubi_eba_write_leb(ubi, vol_id, lnum, buf, 0, l,
UBI_UNKNOWN);
} else {
/*
* When writing static volume, and this is the last logical
* eraseblock, the length (@len) does not have to be aligned to
* the minimal flash I/O unit. The 'ubi_eba_write_leb_st()'
* function accepts exact (unaligned) length and stores it in
* the VID header. And it takes care of proper alignment by
* padding the buffer. Here we just make sure the padding will
* contain zeros, not random trash.
*/
memset(buf + len, 0, vol->usable_leb_size - len);
err = ubi_eba_write_leb_st(ubi, vol_id, lnum, buf, len,
UBI_UNKNOWN, used_ebs);
}
return err;
}
/**
* ubi_more_update_data - write more update data.
* @vol: volume description object
* @buf: write data (user-space memory buffer)
* @count: how much bytes to write
*
* This function writes more data to the volume which is being updated. It may
* be called arbitrary number of times until all of the update data arrive.
* This function returns %0 in case of success, number of bytes written during
* the last call if the whole volume update was successfully finished, and a
* negative error code in case of failure.
*/
int ubi_more_update_data(struct ubi_device *ubi, int vol_id,
const void __user *buf, int count)
{
uint64_t tmp;
struct ubi_volume *vol = ubi->volumes[vol_id];
int lnum, offs, err = 0, len, to_write = count;
dbg_msg("write %d of %lld bytes, %lld already passed",
count, vol->upd_bytes, vol->upd_received);
if (ubi->ro_mode)
return -EROFS;
tmp = vol->upd_received;
offs = do_div(tmp, vol->usable_leb_size);
lnum = tmp;
if (vol->upd_received + count > vol->upd_bytes)
to_write = count = vol->upd_bytes - vol->upd_received;
/*
* When updating volumes, we accumulate whole logical eraseblock of
* data and write it at once.
*/
if (offs != 0) {
/*
* This is a write to the middle of the logical eraseblock. We
* copy the data to our update buffer and wait for more data or
* flush it if the whole eraseblock is written or the update
* is finished.
*/
len = vol->usable_leb_size - offs;
if (len > count)
len = count;
err = copy_from_user(vol->upd_buf + offs, buf, len);
if (err)
return -EFAULT;
if (offs + len == vol->usable_leb_size ||
vol->upd_received + len == vol->upd_bytes) {
int flush_len = offs + len;
/*
* OK, we gathered either the whole eraseblock or this
* is the last chunk, it's time to flush the buffer.
*/
ubi_assert(flush_len <= vol->usable_leb_size);
err = write_leb(ubi, vol_id, lnum, vol->upd_buf,
flush_len, vol->upd_ebs);
if (err)
return err;
}
vol->upd_received += len;
count -= len;
buf += len;
lnum += 1;
}
/*
* If we've got more to write, let's continue. At this point we know we
* are starting from the beginning of an eraseblock.
*/
while (count) {
if (count > vol->usable_leb_size)
len = vol->usable_leb_size;
else
len = count;
err = copy_from_user(vol->upd_buf, buf, len);
if (err)
return -EFAULT;
if (len == vol->usable_leb_size ||
vol->upd_received + len == vol->upd_bytes) {
err = write_leb(ubi, vol_id, lnum, vol->upd_buf, len,
vol->upd_ebs);
if (err)
break;
}
vol->upd_received += len;
count -= len;
lnum += 1;
buf += len;
}
ubi_assert(vol->upd_received <= vol->upd_bytes);
if (vol->upd_received == vol->upd_bytes) {
/* The update is finished, clear the update marker */
err = clear_update_marker(ubi, vol_id, vol->upd_bytes);
if (err)
return err;
err = ubi_wl_flush(ubi);
if (err == 0) {
err = to_write;
kfree(vol->upd_buf);
vol->updating = 0;
}
}
return err;
}
