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volume_id: add LittleFS detection

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Add support for LittleFS to blkid. Not included if FEATURE_BLKID_TYPE
is not selected (neither UUID nor label).

LittleFS is a small fail-safe filesystem designed for embedded
systems. It has strong copy-on-write guarantees and storage on disk
is always kept in a valid state. It also provides a form of dynamic
wear levelling for systems that can not fit a full flash translation
layer. (https://github.com/geky/littlefs)

ARM has introduced it in its Mbed OS 5.7, so it starts to gain focus.
(https://os.mbed.com/blog/entry/littlefs-high-integrity-embedded-fs/)

function                                             old     new   delta
volume_id_probe_lfs                                    -      62     +62
fs1                                                   20      24      +4

Signed-off-by: Sven-Göran Bergh <sgb@systemaxion.se>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Sven-Göran Bergh 2018-01-19 20:36:15 +01:00 committed by Denys Vlasenko
parent f6dd9e0215
commit e411cd071a
3 changed files with 67 additions and 0 deletions
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62
util-linux/volume_id/lfs.c Normal file
View File

@ -0,0 +1,62 @@
/*
* volume_id - reads filesystem label and uuid
*
* Copyright (C) 2018 Sven-Göran Bergh <sgb@systemaxion.se>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config FEATURE_VOLUMEID_LFS
//config: bool "LittleFS filesystem"
//config: default y
//config: depends on VOLUMEID && FEATURE_BLKID_TYPE
//config: help
//config: LittleFS is a small fail-safe filesystem designed for embedded
//config: systems. It has strong copy-on-write guarantees and storage on disk
//config: is always kept in a valid state. It also provides a form of dynamic
//config: wear levelling for systems that can not fit a full flash translation
//config: layer.
//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_LFS) += lfs.o
#include "volume_id_internal.h"
#define LFS_SB1_OFFSET 0x10
#define LFS_MAGIC_NAME "littlefs"
#define LFS_MAGIC_LEN 8
// The superblock is stored in the first metadata pair, i.e the first two blocks.
struct lfs_super_block { // A block in a metadata pair
// /* 0x00 */ uint32_t rev_count; // Revision count
// /* 0x04 */ uint32_t dir_size; // Directory size
// /* 0x08 */ uint64_t tail_ptr; // Tail pointer
/* 0x10 */ uint8_t entry_type; // Entry type
/* 0x11 */ uint8_t entry_len; // Entry length
/* 0x12 */ uint8_t att_len; // Attribute length
/* 0x13 */ uint8_t name_len; // Name length
/* 0x14 */ uint64_t root_dir; // Root directory
/* 0x1C */ uint32_t block_size; // Block size
/* 0x20 */ uint32_t block_count; // Block count
/* 0x24 */ uint16_t ver_major; // Version major
/* 0x26 */ uint16_t ver_minor; // Version minor
/* 0x28 */ uint8_t magic[LFS_MAGIC_LEN]; // Magic string "littlefs"
// /* 0x30 */ uint32_t crc; // CRC-32 checksum
} PACKED;
int FAST_FUNC volume_id_probe_lfs(struct volume_id *id /*,uint64_t off*/)
{
struct lfs_super_block *sb;
// Go for primary super block (ignore second sb)
dbg("lfs: probing at offset 0x%x", LFS_SB1_OFFSET);
sb = volume_id_get_buffer(id, LFS_SB1_OFFSET, sizeof(*sb));
if (!sb)
return -1;
if (memcmp(sb->magic, LFS_MAGIC_NAME, LFS_MAGIC_LEN) != 0)
return -1;
IF_FEATURE_BLKID_TYPE(id->type = LFS_MAGIC_NAME);
return 0;
}

3
util-linux/volume_id/volume_id.c
View File

@ -97,6 +97,9 @@ static const probe_fptr fs1[] = {
#if ENABLE_FEATURE_VOLUMEID_EXFAT
volume_id_probe_exfat,
#endif
#if ENABLE_FEATURE_VOLUMEID_LFS
volume_id_probe_lfs,
#endif
#if ENABLE_FEATURE_VOLUMEID_MAC
volume_id_probe_mac_partition_map,
#endif

2
util-linux/volume_id/volume_id_internal.h
View File

@ -187,6 +187,8 @@ int FAST_FUNC volume_id_probe_iso9660(struct volume_id *id /*,uint64_t off*/);
int FAST_FUNC volume_id_probe_jfs(struct volume_id *id /*,uint64_t off*/);
int FAST_FUNC volume_id_probe_lfs(struct volume_id *id /*,uint64_t off*/);
int FAST_FUNC volume_id_probe_linux_swap(struct volume_id *id /*,uint64_t off*/);
int FAST_FUNC volume_id_probe_luks(struct volume_id *id /*,uint64_t off*/);