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