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mufs: add code to lookup, allocate and free pages in file trees

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S.J.R. van Schaik 2017-05-29 13:59:33 +02:00
parent 88707097fb
commit a88a33ef01
3 changed files with 110 additions and 0 deletions
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1
Makefile
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@ -25,6 +25,7 @@ obj-y += source/core/flash.o
obj-y += source/fs/mufs/block.o
obj-y += source/fs/mufs/super.o
obj-y += source/fs/mufs/tree.o
obj-y += source/ftl/dev.o
obj-y += source/ftl/ftl.o

97
source/fs/mufs/tree.c Normal file
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@ -0,0 +1,97 @@
#include <stdint.h>
#include <bitops.h>
#include <flash.h>
#include <fs/mufs.h>
#include "block.h"
#include "tree.h"
static int mufs_do_lookup(struct mufs *fs, uint32_t *page,
uint32_t base, uint8_t depth, uint32_t va, unsigned alloc)
{
char data[1 << fs->dev->log2_block_size];
uint32_t *table = (uint32_t *)data;
size_t index;
uint8_t log2_nentries = fs->dev->log2_block_size - ilog2(sizeof(uint32_t));
if (!base)
return -1;
if (!depth) {
*page = base;
return 0;
}
if (flash_read(fs->dev, base << fs->dev->log2_block_size, data,
sizeof data) == 0)
return -1;
index = va & ((1 << (log2_nentries * (depth - 1))) - 1);
if (!table[index]) {
if (!alloc || mufs_alloc_block(fs, &table[index]) < 0)
return -1;
}
return mufs_do_lookup(fs, page, table[index], depth - 1, va, alloc);
}
int mufs_lookup_page(struct mufs *fs, struct mufs_tree *tree, uint32_t *page,
uint32_t va)
{
return mufs_do_lookup(fs, page, tree->base, tree->depth, va, 0);
}
int mufs_alloc_page(struct mufs *fs, struct mufs_tree *tree, uint32_t *page,
uint32_t va)
{
return mufs_do_lookup(fs, page, tree->base, tree->depth, va, 1);
}
static int mufs_do_free_page(struct mufs *fs, uint32_t base,
uint8_t depth, uint32_t va)
{
char data[1 << fs->dev->log2_block_size];
uint32_t *table = (uint32_t *)data;
size_t index;
uint8_t log2_nentries = fs->dev->log2_block_size - ilog2(sizeof(uint32_t));
if (!base)
return -1;
if (!depth) {
mufs_free_block(fs, base);
return 0;
}
if (flash_read(fs->dev, base << fs->dev->log2_block_size, data,
sizeof data) == 0)
return -1;
index = va & ((1 << (log2_nentries * (depth - 1))) - 1);
if (mufs_do_free_page(fs, table[index], depth - 1, va) < 0)
return -1;
table[index] = 0;
for (index = 0; index < (UINT32_C(1) << log2_nentries); ++index) {
if (!table[index])
continue;
if (flash_write(fs->dev, base << fs->dev->log2_block_size, data,
sizeof data) == 0)
return -1;
return 0;
}
return mufs_free_block(fs, base);
}
void mufs_free_page(struct mufs *fs, struct mufs_tree *tree, uint32_t va)
{
mufs_do_free_page(fs, tree->base, tree->depth, va);
}

12
source/fs/mufs/tree.h Normal file
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@ -0,0 +1,12 @@
#pragma once
struct mufs_tree {
uint32_t base;
uint8_t depth;
};
int mufs_lookup_page(struct mufs *fs, struct mufs_tree *tree, uint32_t *page,
uint32_t va);
int mufs_alloc_page(struct mufs *fs, struct mufs_tree *tree, uint32_t *page,
uint32_t va);
void mufs_free_page(struct mufs *fs, struct mufs_tree *tree, uint32_t va);