yaffs_packedtags2.c
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/*
* YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
*
* Copyright (C) 2002-2011 Aleph One Ltd.
* for Toby Churchill Ltd and Brightstar Engineering
*
* Created by Charles Manning <charles@aleph1.co.uk>
*
* 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.
*/
#include "yaffs_packedtags2.h"
#include "yportenv.h"
#include "yaffs_trace.h"
/* This code packs a set of extended tags into a binary structure for
* NAND storage
*/
/* Some of the information is "extra" struff which can be packed in to
* speed scanning
* This is defined by having the EXTRA_HEADER_INFO_FLAG set.
*/
/* Extra flags applied to chunk_id */
#define EXTRA_HEADER_INFO_FLAG 0x80000000
#define EXTRA_SHRINK_FLAG 0x40000000
#define EXTRA_SHADOWS_FLAG 0x20000000
#define EXTRA_SPARE_FLAGS 0x10000000
#define ALL_EXTRA_FLAGS 0xf0000000
/* Also, the top 4 bits of the object Id are set to the object type. */
#define EXTRA_OBJECT_TYPE_SHIFT (28)
#define EXTRA_OBJECT_TYPE_MASK ((0x0f) << EXTRA_OBJECT_TYPE_SHIFT)
static void yaffs_dump_packed_tags2_tags_only(
const struct yaffs_packed_tags2_tags_only *ptt)
{
yaffs_trace(YAFFS_TRACE_MTD,
"packed tags obj %d chunk %d byte %d seq %d",
ptt->obj_id, ptt->chunk_id, ptt->n_bytes, ptt->seq_number);
}
static void yaffs_dump_packed_tags2(const struct yaffs_packed_tags2 *pt)
{
yaffs_dump_packed_tags2_tags_only(&pt->t);
}
static void yaffs_dump_tags2(const struct yaffs_ext_tags *t)
{
yaffs_trace(YAFFS_TRACE_MTD,
"ext.tags eccres %d blkbad %d chused %d obj %d chunk%d byte %d del %d ser %d seq %d",
t->ecc_result, t->block_bad, t->chunk_used, t->obj_id,
t->chunk_id, t->n_bytes, t->is_deleted, t->serial_number,
t->seq_number);
}
static int yaffs_check_tags_extra_packable(const struct yaffs_ext_tags *t)
{
if (t->chunk_id != 0 || !t->extra_available)
return 0;
/* Check if the file size is too long to store */
if (t->extra_obj_type == YAFFS_OBJECT_TYPE_FILE &&
(t->extra_file_size >> 31) != 0)
return 0;
return 1;
}
void yaffs_pack_tags2_tags_only(struct yaffs_packed_tags2_tags_only *ptt,
const struct yaffs_ext_tags *t)
{
ptt->chunk_id = t->chunk_id;
ptt->seq_number = t->seq_number;
ptt->n_bytes = t->n_bytes;
ptt->obj_id = t->obj_id;
/* Only store extra tags for object headers.
* If it is a file then only store if the file size is short\
* enough to fit.
*/
if (yaffs_check_tags_extra_packable(t)) {
/* Store the extra header info instead */
/* We save the parent object in the chunk_id */
ptt->chunk_id = EXTRA_HEADER_INFO_FLAG | t->extra_parent_id;
if (t->extra_is_shrink)
ptt->chunk_id |= EXTRA_SHRINK_FLAG;
if (t->extra_shadows)
ptt->chunk_id |= EXTRA_SHADOWS_FLAG;
ptt->obj_id &= ~EXTRA_OBJECT_TYPE_MASK;
ptt->obj_id |= (t->extra_obj_type << EXTRA_OBJECT_TYPE_SHIFT);
if (t->extra_obj_type == YAFFS_OBJECT_TYPE_HARDLINK)
ptt->n_bytes = t->extra_equiv_id;
else if (t->extra_obj_type == YAFFS_OBJECT_TYPE_FILE)
ptt->n_bytes = (unsigned) t->extra_file_size;
else
ptt->n_bytes = 0;
}
yaffs_dump_packed_tags2_tags_only(ptt);
yaffs_dump_tags2(t);
}
void yaffs_pack_tags2(struct yaffs_packed_tags2 *pt,
const struct yaffs_ext_tags *t, int tags_ecc)
{
yaffs_pack_tags2_tags_only(&pt->t, t);
if (tags_ecc)
yaffs_ecc_calc_other((unsigned char *)&pt->t,
sizeof(struct yaffs_packed_tags2_tags_only),
&pt->ecc);
}
void yaffs_unpack_tags2_tags_only(struct yaffs_ext_tags *t,
struct yaffs_packed_tags2_tags_only *ptt)
{
memset(t, 0, sizeof(struct yaffs_ext_tags));
if (ptt->seq_number == 0xffffffff)
return;
t->block_bad = 0;
t->chunk_used = 1;
t->obj_id = ptt->obj_id;
t->chunk_id = ptt->chunk_id;
t->n_bytes = ptt->n_bytes;
t->is_deleted = 0;
t->serial_number = 0;
t->seq_number = ptt->seq_number;
/* Do extra header info stuff */
if (ptt->chunk_id & EXTRA_HEADER_INFO_FLAG) {
t->chunk_id = 0;
t->n_bytes = 0;
t->extra_available = 1;
t->extra_parent_id = ptt->chunk_id & (~(ALL_EXTRA_FLAGS));
t->extra_is_shrink = ptt->chunk_id & EXTRA_SHRINK_FLAG ? 1 : 0;
t->extra_shadows = ptt->chunk_id & EXTRA_SHADOWS_FLAG ? 1 : 0;
t->extra_obj_type = ptt->obj_id >> EXTRA_OBJECT_TYPE_SHIFT;
t->obj_id &= ~EXTRA_OBJECT_TYPE_MASK;
if (t->extra_obj_type == YAFFS_OBJECT_TYPE_HARDLINK)
t->extra_equiv_id = ptt->n_bytes;
else
t->extra_file_size = ptt->n_bytes;
}
yaffs_dump_packed_tags2_tags_only(ptt);
yaffs_dump_tags2(t);
}
void yaffs_unpack_tags2(struct yaffs_ext_tags *t, struct yaffs_packed_tags2 *pt,
int tags_ecc)
{
enum yaffs_ecc_result ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
if (pt->t.seq_number != 0xffffffff && tags_ecc) {
/* Chunk is in use and we need to do ECC */
struct yaffs_ecc_other ecc;
int result;
yaffs_ecc_calc_other((unsigned char *)&pt->t,
sizeof(struct yaffs_packed_tags2_tags_only),
&ecc);
result =
yaffs_ecc_correct_other((unsigned char *)&pt->t,
sizeof(struct yaffs_packed_tags2_tags_only),
&pt->ecc, &ecc);
switch (result) {
case 0:
ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
break;
case 1:
ecc_result = YAFFS_ECC_RESULT_FIXED;
break;
case -1:
ecc_result = YAFFS_ECC_RESULT_UNFIXED;
break;
default:
ecc_result = YAFFS_ECC_RESULT_UNKNOWN;
}
}
yaffs_unpack_tags2_tags_only(t, &pt->t);
t->ecc_result = ecc_result;
yaffs_dump_packed_tags2(pt);
yaffs_dump_tags2(t);
}