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segment.c
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segment.c
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/*
* segment.c
*
* Copyright (c) 2007-2008 Joern Engel <joern@logfs.org>
*
* License: GPL version 2
*/
#include <asm/types.h>
#include <errno.h>
#include "kerncompat.h"
#include "logfs_abi.h"
#include "logfs.h"
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) < (b) ? (a) : (b))
static inline void hexdump(const char *prefix, void *buf, size_t len)
{
unsigned char *c = buf;
int i;
printf("%s", prefix);
for (i = 0; i < len; i++) {
printf("%02x ", c[i]);
if (i % 8 == 7)
printf(" ");
if (i % 16 == 15)
printf("\n");
}
printf("\n");
}
static void copybuf(struct logfs_area *area, void *buf, size_t len)
{
memcpy(area->buf + area->used_bytes, buf, len);
area->used_bytes += len;
}
u32 get_segment(struct super_block *sb)
{
u64 ofs;
u32 segno;
int err;
do {
segno = sb->lastseg;
ofs = (u64)segno * sb->segsize;
sb->lastseg += 1;
if (sb->lastseg > sb->no_segs)
fail("no more free segments");
err = sb->dev_ops->erase(sb, ofs, sb->segsize);
if (err) {
/* bad segment */
sb->segment_entry[segno].ec_level = cpu_to_be32(BADSEG);
sb->segment_entry[segno].valid = cpu_to_be32(RESERVED);
printf("Bad block at 0x%llx\n", ofs);
}
} while (err);
return segno;
}
static void __init_area(struct super_block *sb, struct logfs_area *area,
u8 level)
{
struct logfs_segment_header *sh = area->buf;
memset(area->buf, 0xff, sb->segsize);
area->segno = get_segment(sb);
area->used_bytes = sizeof(*sh);
sh->pad = 0;
sh->type = SEG_OSTORE;
sh->level = level;
sh->segno = cpu_to_be32(area->segno);
sh->ec = cpu_to_be32(1);
sh->gec = cpu_to_be64(area->segno);
sh->crc = logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4);
}
static void init_area(struct super_block *sb, struct logfs_area *area,
u8 level)
{
if (area->buf)
return;
area->buf = malloc(sb->segsize);
__init_area(sb, area, level);
}
static int finish_area(struct super_block *sb, struct logfs_area *area,
int final, u8 level)
{
u64 ofs = (u64)area->segno * sb->segsize;
int err;
err = sb->dev_ops->write(sb, ofs, sb->segsize, area->buf);
if (err)
return err;
sb->segment_entry[area->segno].ec_level = ec_level(1, level);
sb->segment_entry[area->segno].valid =
cpu_to_be32(area->used_bytes - LOGFS_SEGMENT_HEADERSIZE);
if (final)
return 0;
__init_area(sb, area, level);
return 0;
}
static int grow_inode(struct super_block *sb, u64 ino, size_t len)
{
struct inode *inode = find_or_create_inode(sb, ino);
if (!inode)
return -ENOMEM;
inode->di.di_used_bytes =
cpu_to_be64(len + be64_to_cpu(inode->di.di_used_bytes));
sb->used_bytes += len;
return 0;
}
static int obj_len(struct super_block *sb, int obj_type)
{
switch (obj_type) {
case OBJ_DENTRY:
return sizeof(struct logfs_disk_dentry);
case OBJ_INODE:
return sizeof(struct logfs_disk_inode);
case OBJ_BLOCK:
return sb->blocksize;
default:
BUG();
}
}
s64 logfs_segment_write(struct super_block *sb, void *buf, u8 type,
u64 ino, u64 bix, u8 level)
{
struct logfs_object_header oh;
struct logfs_area *area;
int err;
s64 ofs;
u16 len = obj_len(sb, type);
if (ino == LOGFS_INO_MASTER)
level += LOGFS_MAX_LEVELS;
area = sb->area + level;
memset(&oh, 0, sizeof(oh));
oh.len = cpu_to_be16(len);
oh.type = type;
oh.compr = COMPR_NONE;
oh.ino = cpu_to_be64(ino);
oh.bix = cpu_to_be64(bix);
oh.crc = logfs_crc32(&oh, LOGFS_OBJECT_HEADERSIZE - 4, 4);
oh.data_crc = logfs_crc32(buf, len, 0);
init_area(sb, area, level);
if (area->used_bytes + sizeof(oh) + sb->blocksize > sb->segsize) {
err = finish_area(sb, area, 0, level);
if (err)
return err;
}
ofs = area->segno * sb->segsize + area->used_bytes;
copybuf(area, &oh, sizeof(oh));
copybuf(area, buf, len);
err = grow_inode(sb, ino, sizeof(oh) + len);
if (err)
return err;
return ofs;
}
int flush_segments(struct super_block *sb)
{
struct logfs_area *area;
int i, err;
for (i = 0; i < LOGFS_NO_AREAS; i++) {
area = sb->area + i;
if (area->buf) {
err = finish_area(sb, area, 1, i);
if (err)
return err;
}
}
return 0;
}