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https://github.com/eledio-devices/thirdparty-littlefs.git
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106b06a457
The core algorithim that backs this filesystem's goal of fault tolerance is the alternating of "metadata pairs". Backed by a simple core function for reading and writing, makes heavy use of c99 designated initializers for passing info about multiple chunks in an erase block.
96 lines
2.0 KiB
C
96 lines
2.0 KiB
C
/*
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* The little filesystem
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*
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* Copyright (c) 2017 Christopher Haster
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* Distributed under the MIT license
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*/
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#ifndef LFS_H
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#define LFS_H
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#include "lfs_config.h"
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#include "lfs_bd.h"
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// Data structures
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enum lfs_error {
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LFS_ERROR_OK = 0,
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LFS_ERROR_CORRUPT = -3,
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};
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typedef struct lfs_free {
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lfs_disk_struct lfs_disk_free {
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lfs_ino_t head;
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lfs_word_t ioff;
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lfs_word_t icount;
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lfs_word_t rev;
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} d;
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} lfs_free_t;
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typedef struct lfs_dir {
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lfs_ino_t pair[2];
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lfs_disk_struct lfs_disk_dir {
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lfs_word_t rev;
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lfs_size_t size;
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lfs_ino_t tail[2];
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lfs_ino_t parent[2];
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struct lfs_disk_free free;
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} d;
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} lfs_dir_t;
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typedef struct lfs_entry {
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lfs_ino_t dir[2];
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lfs_off_t off;
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lfs_disk_struct lfs_disk_entry {
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uint16_t type;
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uint16_t len;
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union {
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lfs_disk_struct {
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lfs_ino_t head;
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lfs_size_t size;
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char name[LFS_NAME_MAX];
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} file;
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lfs_disk_struct {
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lfs_ino_t dir[2];
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char name[LFS_NAME_MAX];
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} dir;
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lfs_disk_struct {
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char magic[4];
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uint32_t read_size;
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uint32_t write_size;
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uint32_t erase_size;
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uint32_t erase_count;
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} superblock;
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} value;
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} d;
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} lfs_entry_t;
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typedef struct lfs_superblock {
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lfs_ino_t pair[2];
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lfs_disk_struct lfs_disk_superblock {
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lfs_word_t rev;
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uint32_t size;
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lfs_ino_t root[2];
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char magic[8];
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uint32_t block_size;
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uint32_t block_count;
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} d;
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} lfs_superblock_t;
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// Little filesystem type
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typedef struct lfs {
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lfs_bd_t *bd;
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const struct lfs_bd_ops *ops;
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lfs_free_t free;
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struct lfs_bd_info info;
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} lfs_t;
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// Functions
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lfs_error_t lfs_create(lfs_t *lfs, lfs_bd_t *bd, const struct lfs_bd_ops *bd_ops);
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lfs_error_t lfs_format(lfs_t *lfs);
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lfs_error_t lfs_mount(lfs_t *lfs);
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#endif
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