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Diffstat (limited to 'lib/littlefs/lfs2.h')
| -rw-r--r-- | lib/littlefs/lfs2.h | 651 |
1 files changed, 651 insertions, 0 deletions
diff --git a/lib/littlefs/lfs2.h b/lib/littlefs/lfs2.h new file mode 100644 index 000000000..fdbe007cc --- /dev/null +++ b/lib/littlefs/lfs2.h @@ -0,0 +1,651 @@ +/* + * The little filesystem + * + * Copyright (c) 2017, Arm Limited. All rights reserved. + * SPDX-License-Identifier: BSD-3-Clause + */ +#ifndef LFS2_H +#define LFS2_H + +#include <stdint.h> +#include <stdbool.h> + +#ifdef __cplusplus +extern "C" +{ +#endif + + +/// Version info /// + +// Software library version +// Major (top-nibble), incremented on backwards incompatible changes +// Minor (bottom-nibble), incremented on feature additions +#define LFS2_VERSION 0x00020001 +#define LFS2_VERSION_MAJOR (0xffff & (LFS2_VERSION >> 16)) +#define LFS2_VERSION_MINOR (0xffff & (LFS2_VERSION >> 0)) + +// Version of On-disk data structures +// Major (top-nibble), incremented on backwards incompatible changes +// Minor (bottom-nibble), incremented on feature additions +#define LFS2_DISK_VERSION 0x00020000 +#define LFS2_DISK_VERSION_MAJOR (0xffff & (LFS2_DISK_VERSION >> 16)) +#define LFS2_DISK_VERSION_MINOR (0xffff & (LFS2_DISK_VERSION >> 0)) + + +/// Definitions /// + +// Type definitions +typedef uint32_t lfs2_size_t; +typedef uint32_t lfs2_off_t; + +typedef int32_t lfs2_ssize_t; +typedef int32_t lfs2_soff_t; + +typedef uint32_t lfs2_block_t; + +// Maximum name size in bytes, may be redefined to reduce the size of the +// info struct. Limited to <= 1022. Stored in superblock and must be +// respected by other littlefs drivers. +#ifndef LFS2_NAME_MAX +#define LFS2_NAME_MAX 255 +#endif + +// Maximum size of a file in bytes, may be redefined to limit to support other +// drivers. Limited on disk to <= 4294967296. However, above 2147483647 the +// functions lfs2_file_seek, lfs2_file_size, and lfs2_file_tell will return +// incorrect values due to using signed integers. Stored in superblock and +// must be respected by other littlefs drivers. +#ifndef LFS2_FILE_MAX +#define LFS2_FILE_MAX 2147483647 +#endif + +// Maximum size of custom attributes in bytes, may be redefined, but there is +// no real benefit to using a smaller LFS2_ATTR_MAX. Limited to <= 1022. +#ifndef LFS2_ATTR_MAX +#define LFS2_ATTR_MAX 1022 +#endif + +// Possible error codes, these are negative to allow +// valid positive return values +enum lfs2_error { + LFS2_ERR_OK = 0, // No error + LFS2_ERR_IO = -5, // Error during device operation + LFS2_ERR_CORRUPT = -84, // Corrupted + LFS2_ERR_NOENT = -2, // No directory entry + LFS2_ERR_EXIST = -17, // Entry already exists + LFS2_ERR_NOTDIR = -20, // Entry is not a dir + LFS2_ERR_ISDIR = -21, // Entry is a dir + LFS2_ERR_NOTEMPTY = -39, // Dir is not empty + LFS2_ERR_BADF = -9, // Bad file number + LFS2_ERR_FBIG = -27, // File too large + LFS2_ERR_INVAL = -22, // Invalid parameter + LFS2_ERR_NOSPC = -28, // No space left on device + LFS2_ERR_NOMEM = -12, // No more memory available + LFS2_ERR_NOATTR = -61, // No data/attr available + LFS2_ERR_NAMETOOLONG = -36, // File name too long +}; + +// File types +enum lfs2_type { + // file types + LFS2_TYPE_REG = 0x001, + LFS2_TYPE_DIR = 0x002, + + // internally used types + LFS2_TYPE_SPLICE = 0x400, + LFS2_TYPE_NAME = 0x000, + LFS2_TYPE_STRUCT = 0x200, + LFS2_TYPE_USERATTR = 0x300, + LFS2_TYPE_FROM = 0x100, + LFS2_TYPE_TAIL = 0x600, + LFS2_TYPE_GLOBALS = 0x700, + LFS2_TYPE_CRC = 0x500, + + // internally used type specializations + LFS2_TYPE_CREATE = 0x401, + LFS2_TYPE_DELETE = 0x4ff, + LFS2_TYPE_SUPERBLOCK = 0x0ff, + LFS2_TYPE_DIRSTRUCT = 0x200, + LFS2_TYPE_CTZSTRUCT = 0x202, + LFS2_TYPE_INLINESTRUCT = 0x201, + LFS2_TYPE_SOFTTAIL = 0x600, + LFS2_TYPE_HARDTAIL = 0x601, + LFS2_TYPE_MOVESTATE = 0x7ff, + + // internal chip sources + LFS2_FROM_NOOP = 0x000, + LFS2_FROM_MOVE = 0x101, + LFS2_FROM_USERATTRS = 0x102, +}; + +// File open flags +enum lfs2_open_flags { + // open flags + LFS2_O_RDONLY = 1, // Open a file as read only + LFS2_O_WRONLY = 2, // Open a file as write only + LFS2_O_RDWR = 3, // Open a file as read and write + LFS2_O_CREAT = 0x0100, // Create a file if it does not exist + LFS2_O_EXCL = 0x0200, // Fail if a file already exists + LFS2_O_TRUNC = 0x0400, // Truncate the existing file to zero size + LFS2_O_APPEND = 0x0800, // Move to end of file on every write + + // internally used flags + LFS2_F_DIRTY = 0x010000, // File does not match storage + LFS2_F_WRITING = 0x020000, // File has been written since last flush + LFS2_F_READING = 0x040000, // File has been read since last flush + LFS2_F_ERRED = 0x080000, // An error occured during write + LFS2_F_INLINE = 0x100000, // Currently inlined in directory entry + LFS2_F_OPENED = 0x200000, // File has been opened +}; + +// File seek flags +enum lfs2_whence_flags { + LFS2_SEEK_SET = 0, // Seek relative to an absolute position + LFS2_SEEK_CUR = 1, // Seek relative to the current file position + LFS2_SEEK_END = 2, // Seek relative to the end of the file +}; + + +// Configuration provided during initialization of the littlefs +struct lfs2_config { + // Opaque user provided context that can be used to pass + // information to the block device operations + void *context; + + // Read a region in a block. Negative error codes are propogated + // to the user. + int (*read)(const struct lfs2_config *c, lfs2_block_t block, + lfs2_off_t off, void *buffer, lfs2_size_t size); + + // Program a region in a block. The block must have previously + // been erased. Negative error codes are propogated to the user. + // May return LFS2_ERR_CORRUPT if the block should be considered bad. + int (*prog)(const struct lfs2_config *c, lfs2_block_t block, + lfs2_off_t off, const void *buffer, lfs2_size_t size); + + // Erase a block. A block must be erased before being programmed. + // The state of an erased block is undefined. Negative error codes + // are propogated to the user. + // May return LFS2_ERR_CORRUPT if the block should be considered bad. + int (*erase)(const struct lfs2_config *c, lfs2_block_t block); + + // Sync the state of the underlying block device. Negative error codes + // are propogated to the user. + int (*sync)(const struct lfs2_config *c); + + // Minimum size of a block read. All read operations will be a + // multiple of this value. + lfs2_size_t read_size; + + // Minimum size of a block program. All program operations will be a + // multiple of this value. + lfs2_size_t prog_size; + + // Size of an erasable block. This does not impact ram consumption and + // may be larger than the physical erase size. However, non-inlined files + // take up at minimum one block. Must be a multiple of the read + // and program sizes. + lfs2_size_t block_size; + + // Number of erasable blocks on the device. + lfs2_size_t block_count; + + // Number of erase cycles before littlefs evicts metadata logs and moves + // the metadata to another block. Suggested values are in the + // range 100-1000, with large values having better performance at the cost + // of less consistent wear distribution. + // + // Set to -1 to disable block-level wear-leveling. + int32_t block_cycles; + + // Size of block caches. Each cache buffers a portion of a block in RAM. + // The littlefs needs a read cache, a program cache, and one additional + // cache per file. Larger caches can improve performance by storing more + // data and reducing the number of disk accesses. Must be a multiple of + // the read and program sizes, and a factor of the block size. + lfs2_size_t cache_size; + + // Size of the lookahead buffer in bytes. A larger lookahead buffer + // increases the number of blocks found during an allocation pass. The + // lookahead buffer is stored as a compact bitmap, so each byte of RAM + // can track 8 blocks. Must be a multiple of 8. + lfs2_size_t lookahead_size; + + // Optional statically allocated read buffer. Must be cache_size. + // By default lfs2_malloc is used to allocate this buffer. + void *read_buffer; + + // Optional statically allocated program buffer. Must be cache_size. + // By default lfs2_malloc is used to allocate this buffer. + void *prog_buffer; + + // Optional statically allocated lookahead buffer. Must be lookahead_size + // and aligned to a 32-bit boundary. By default lfs2_malloc is used to + // allocate this buffer. + void *lookahead_buffer; + + // Optional upper limit on length of file names in bytes. No downside for + // larger names except the size of the info struct which is controlled by + // the LFS2_NAME_MAX define. Defaults to LFS2_NAME_MAX when zero. Stored in + // superblock and must be respected by other littlefs drivers. + lfs2_size_t name_max; + + // Optional upper limit on files in bytes. No downside for larger files + // but must be <= LFS2_FILE_MAX. Defaults to LFS2_FILE_MAX when zero. Stored + // in superblock and must be respected by other littlefs drivers. + lfs2_size_t file_max; + + // Optional upper limit on custom attributes in bytes. No downside for + // larger attributes size but must be <= LFS2_ATTR_MAX. Defaults to + // LFS2_ATTR_MAX when zero. + lfs2_size_t attr_max; +}; + +// File info structure +struct lfs2_info { + // Type of the file, either LFS2_TYPE_REG or LFS2_TYPE_DIR + uint8_t type; + + // Size of the file, only valid for REG files. Limited to 32-bits. + lfs2_size_t size; + + // Name of the file stored as a null-terminated string. Limited to + // LFS2_NAME_MAX+1, which can be changed by redefining LFS2_NAME_MAX to + // reduce RAM. LFS2_NAME_MAX is stored in superblock and must be + // respected by other littlefs drivers. + char name[LFS2_NAME_MAX+1]; +}; + +// Custom attribute structure, used to describe custom attributes +// committed atomically during file writes. +struct lfs2_attr { + // 8-bit type of attribute, provided by user and used to + // identify the attribute + uint8_t type; + + // Pointer to buffer containing the attribute + void *buffer; + + // Size of attribute in bytes, limited to LFS2_ATTR_MAX + lfs2_size_t size; +}; + +// Optional configuration provided during lfs2_file_opencfg +struct lfs2_file_config { + // Optional statically allocated file buffer. Must be cache_size. + // By default lfs2_malloc is used to allocate this buffer. + void *buffer; + + // Optional list of custom attributes related to the file. If the file + // is opened with read access, these attributes will be read from disk + // during the open call. If the file is opened with write access, the + // attributes will be written to disk every file sync or close. This + // write occurs atomically with update to the file's contents. + // + // Custom attributes are uniquely identified by an 8-bit type and limited + // to LFS2_ATTR_MAX bytes. When read, if the stored attribute is smaller + // than the buffer, it will be padded with zeros. If the stored attribute + // is larger, then it will be silently truncated. If the attribute is not + // found, it will be created implicitly. + struct lfs2_attr *attrs; + + // Number of custom attributes in the list + lfs2_size_t attr_count; +}; + + +/// internal littlefs data structures /// +typedef struct lfs2_cache { + lfs2_block_t block; + lfs2_off_t off; + lfs2_size_t size; + uint8_t *buffer; +} lfs2_cache_t; + +typedef struct lfs2_mdir { + lfs2_block_t pair[2]; + uint32_t rev; + lfs2_off_t off; + uint32_t etag; + uint16_t count; + bool erased; + bool split; + lfs2_block_t tail[2]; +} lfs2_mdir_t; + +// littlefs directory type +typedef struct lfs2_dir { + struct lfs2_dir *next; + uint16_t id; + uint8_t type; + lfs2_mdir_t m; + + lfs2_off_t pos; + lfs2_block_t head[2]; +} lfs2_dir_t; + +// littlefs file type +typedef struct lfs2_file { + struct lfs2_file *next; + uint16_t id; + uint8_t type; + lfs2_mdir_t m; + + struct lfs2_ctz { + lfs2_block_t head; + lfs2_size_t size; + } ctz; + + uint32_t flags; + lfs2_off_t pos; + lfs2_block_t block; + lfs2_off_t off; + lfs2_cache_t cache; + + const struct lfs2_file_config *cfg; +} lfs2_file_t; + +typedef struct lfs2_superblock { + uint32_t version; + lfs2_size_t block_size; + lfs2_size_t block_count; + lfs2_size_t name_max; + lfs2_size_t file_max; + lfs2_size_t attr_max; +} lfs2_superblock_t; + +// The littlefs filesystem type +typedef struct lfs2 { + lfs2_cache_t rcache; + lfs2_cache_t pcache; + + lfs2_block_t root[2]; + struct lfs2_mlist { + struct lfs2_mlist *next; + uint16_t id; + uint8_t type; + lfs2_mdir_t m; + } *mlist; + uint32_t seed; + + struct lfs2_gstate { + uint32_t tag; + lfs2_block_t pair[2]; + } gstate, gpending, gdelta; + + struct lfs2_free { + lfs2_block_t off; + lfs2_block_t size; + lfs2_block_t i; + lfs2_block_t ack; + uint32_t *buffer; + } free; + + const struct lfs2_config *cfg; + lfs2_size_t name_max; + lfs2_size_t file_max; + lfs2_size_t attr_max; + +#ifdef LFS2_MIGRATE + struct lfs21 *lfs21; +#endif +} lfs2_t; + + +/// Filesystem functions /// + +// Format a block device with the littlefs +// +// Requires a littlefs object and config struct. This clobbers the littlefs +// object, and does not leave the filesystem mounted. The config struct must +// be zeroed for defaults and backwards compatibility. +// +// Returns a negative error code on failure. +int lfs2_format(lfs2_t *lfs2, const struct lfs2_config *config); + +// Mounts a littlefs +// +// Requires a littlefs object and config struct. Multiple filesystems +// may be mounted simultaneously with multiple littlefs objects. Both +// lfs2 and config must be allocated while mounted. The config struct must +// be zeroed for defaults and backwards compatibility. +// +// Returns a negative error code on failure. +int lfs2_mount(lfs2_t *lfs2, const struct lfs2_config *config); + +// Unmounts a littlefs +// +// Does nothing besides releasing any allocated resources. +// Returns a negative error code on failure. +int lfs2_unmount(lfs2_t *lfs2); + +/// General operations /// + +// Removes a file or directory +// +// If removing a directory, the directory must be empty. +// Returns a negative error code on failure. +int lfs2_remove(lfs2_t *lfs2, const char *path); + +// Rename or move a file or directory +// +// If the destination exists, it must match the source in type. +// If the destination is a directory, the directory must be empty. +// +// Returns a negative error code on failure. +int lfs2_rename(lfs2_t *lfs2, const char *oldpath, const char *newpath); + +// Find info about a file or directory +// +// Fills out the info structure, based on the specified file or directory. +// Returns a negative error code on failure. +int lfs2_stat(lfs2_t *lfs2, const char *path, struct lfs2_info *info); + +// Get a custom attribute +// +// Custom attributes are uniquely identified by an 8-bit type and limited +// to LFS2_ATTR_MAX bytes. When read, if the stored attribute is smaller than +// the buffer, it will be padded with zeros. If the stored attribute is larger, +// then it will be silently truncated. If no attribute is found, the error +// LFS2_ERR_NOATTR is returned and the buffer is filled with zeros. +// +// Returns the size of the attribute, or a negative error code on failure. +// Note, the returned size is the size of the attribute on disk, irrespective +// of the size of the buffer. This can be used to dynamically allocate a buffer +// or check for existance. +lfs2_ssize_t lfs2_getattr(lfs2_t *lfs2, const char *path, + uint8_t type, void *buffer, lfs2_size_t size); + +// Set custom attributes +// +// Custom attributes are uniquely identified by an 8-bit type and limited +// to LFS2_ATTR_MAX bytes. If an attribute is not found, it will be +// implicitly created. +// +// Returns a negative error code on failure. +int lfs2_setattr(lfs2_t *lfs2, const char *path, + uint8_t type, const void *buffer, lfs2_size_t size); + +// Removes a custom attribute +// +// If an attribute is not found, nothing happens. +// +// Returns a negative error code on failure. +int lfs2_removeattr(lfs2_t *lfs2, const char *path, uint8_t type); + + +/// File operations /// + +// Open a file +// +// The mode that the file is opened in is determined by the flags, which +// are values from the enum lfs2_open_flags that are bitwise-ored together. +// +// Returns a negative error code on failure. +int lfs2_file_open(lfs2_t *lfs2, lfs2_file_t *file, + const char *path, int flags); + +// Open a file with extra configuration +// +// The mode that the file is opened in is determined by the flags, which +// are values from the enum lfs2_open_flags that are bitwise-ored together. +// +// The config struct provides additional config options per file as described +// above. The config struct must be allocated while the file is open, and the +// config struct must be zeroed for defaults and backwards compatibility. +// +// Returns a negative error code on failure. +int lfs2_file_opencfg(lfs2_t *lfs2, lfs2_file_t *file, + const char *path, int flags, + const struct lfs2_file_config *config); + +// Close a file +// +// Any pending writes are written out to storage as though +// sync had been called and releases any allocated resources. +// +// Returns a negative error code on failure. +int lfs2_file_close(lfs2_t *lfs2, lfs2_file_t *file); + +// Synchronize a file on storage +// +// Any pending writes are written out to storage. +// Returns a negative error code on failure. +int lfs2_file_sync(lfs2_t *lfs2, lfs2_file_t *file); + +// Read data from file +// +// Takes a buffer and size indicating where to store the read data. +// Returns the number of bytes read, or a negative error code on failure. +lfs2_ssize_t lfs2_file_read(lfs2_t *lfs2, lfs2_file_t *file, + void *buffer, lfs2_size_t size); + +// Write data to file +// +// Takes a buffer and size indicating the data to write. The file will not +// actually be updated on the storage until either sync or close is called. +// +// Returns the number of bytes written, or a negative error code on failure. +lfs2_ssize_t lfs2_file_write(lfs2_t *lfs2, lfs2_file_t *file, + const void *buffer, lfs2_size_t size); + +// Change the position of the file +// +// The change in position is determined by the offset and whence flag. +// Returns the new position of the file, or a negative error code on failure. +lfs2_soff_t lfs2_file_seek(lfs2_t *lfs2, lfs2_file_t *file, + lfs2_soff_t off, int whence); + +// Truncates the size of the file to the specified size +// +// Returns a negative error code on failure. +int lfs2_file_truncate(lfs2_t *lfs2, lfs2_file_t *file, lfs2_off_t size); + +// Return the position of the file +// +// Equivalent to lfs2_file_seek(lfs2, file, 0, LFS2_SEEK_CUR) +// Returns the position of the file, or a negative error code on failure. +lfs2_soff_t lfs2_file_tell(lfs2_t *lfs2, lfs2_file_t *file); + +// Change the position of the file to the beginning of the file +// +// Equivalent to lfs2_file_seek(lfs2, file, 0, LFS2_SEEK_SET) +// Returns a negative error code on failure. +int lfs2_file_rewind(lfs2_t *lfs2, lfs2_file_t *file); + +// Return the size of the file +// +// Similar to lfs2_file_seek(lfs2, file, 0, LFS2_SEEK_END) +// Returns the size of the file, or a negative error code on failure. +lfs2_soff_t lfs2_file_size(lfs2_t *lfs2, lfs2_file_t *file); + + +/// Directory operations /// + +// Create a directory +// +// Returns a negative error code on failure. +int lfs2_mkdir(lfs2_t *lfs2, const char *path); + +// Open a directory +// +// Once open a directory can be used with read to iterate over files. +// Returns a negative error code on failure. +int lfs2_dir_open(lfs2_t *lfs2, lfs2_dir_t *dir, const char *path); + +// Close a directory +// +// Releases any allocated resources. +// Returns a negative error code on failure. +int lfs2_dir_close(lfs2_t *lfs2, lfs2_dir_t *dir); + +// Read an entry in the directory +// +// Fills out the info structure, based on the specified file or directory. +// Returns a positive value on success, 0 at the end of directory, +// or a negative error code on failure. +int lfs2_dir_read(lfs2_t *lfs2, lfs2_dir_t *dir, struct lfs2_info *info); + +// Change the position of the directory +// +// The new off must be a value previous returned from tell and specifies +// an absolute offset in the directory seek. +// +// Returns a negative error code on failure. +int lfs2_dir_seek(lfs2_t *lfs2, lfs2_dir_t *dir, lfs2_off_t off); + +// Return the position of the directory +// +// The returned offset is only meant to be consumed by seek and may not make +// sense, but does indicate the current position in the directory iteration. +// +// Returns the position of the directory, or a negative error code on failure. +lfs2_soff_t lfs2_dir_tell(lfs2_t *lfs2, lfs2_dir_t *dir); + +// Change the position of the directory to the beginning of the directory +// +// Returns a negative error code on failure. +int lfs2_dir_rewind(lfs2_t *lfs2, lfs2_dir_t *dir); + + +/// Filesystem-level filesystem operations + +// Finds the current size of the filesystem +// +// Note: Result is best effort. If files share COW structures, the returned +// size may be larger than the filesystem actually is. +// +// Returns the number of allocated blocks, or a negative error code on failure. +lfs2_ssize_t lfs2_fs_size(lfs2_t *lfs2); + +// Traverse through all blocks in use by the filesystem +// +// The provided callback will be called with each block address that is +// currently in use by the filesystem. This can be used to determine which +// blocks are in use or how much of the storage is available. +// +// Returns a negative error code on failure. +int lfs2_fs_traverse(lfs2_t *lfs2, int (*cb)(void*, lfs2_block_t), void *data); + +#ifdef LFS2_MIGRATE +// Attempts to migrate a previous version of littlefs +// +// Behaves similarly to the lfs2_format function. Attempts to mount +// the previous version of littlefs and update the filesystem so it can be +// mounted with the current version of littlefs. +// +// Requires a littlefs object and config struct. This clobbers the littlefs +// object, and does not leave the filesystem mounted. The config struct must +// be zeroed for defaults and backwards compatibility. +// +// Returns a negative error code on failure. +int lfs2_migrate(lfs2_t *lfs2, const struct lfs2_config *cfg); +#endif + + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif |