blob: a163a353d507d4d36db1f879c4c45b23aea7c3e4 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
/*
* volume_id - reads filesystem label and uuid
*
* Copyright (C) 2020 Norbert Lange <nolange79@gmail.com>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config FEATURE_VOLUMEID_EROFS
//config: bool "erofs filesystem"
//config: default y
//config: depends on VOLUMEID
//config: help
//config: Erofs is a compressed readonly filesystem for Linux.
//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_EROFS) += erofs.o
#include "volume_id_internal.h"
#define EROFS_SUPER_MAGIC_V1 0xE0F5E1E2
#define EROFS_SUPER_OFFSET 1024
#define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001
/* 128-byte erofs on-disk super block */
struct erofs_super_block {
uint32_t magic; /* file system magic number */
uint32_t checksum; /* crc32c(super_block) */
uint32_t feature_compat;
uint8_t blkszbits; /* support block_size == PAGE_SIZE only */
uint8_t reserved;
uint16_t root_nid; /* nid of root directory */
uint64_t inos; /* total valid ino # (== f_files - f_favail) */
uint64_t build_time; /* inode v1 time derivation */
uint32_t build_time_nsec; /* inode v1 time derivation in nano scale */
uint32_t blocks; /* used for statfs */
uint32_t meta_blkaddr; /* start block address of metadata area */
uint32_t xattr_blkaddr; /* start block address of shared xattr area */
uint8_t uuid[16]; /* 128-bit uuid for volume */
uint8_t volume_name[16]; /* volume name */
uint32_t feature_incompat;
uint8_t reserved2[44];
} PACKED;
int FAST_FUNC volume_id_probe_erofs(struct volume_id *id /*,uint64_t off*/)
{
struct erofs_super_block *sb;
BUILD_BUG_ON(sizeof(struct erofs_super_block) != 128);
dbg("erofs: probing at offset 0x%llx", EROFS_SUPER_OFFSET);
sb = volume_id_get_buffer(id, EROFS_SUPER_OFFSET, sizeof(*sb));
if (!sb)
return -1;
if (sb->magic != cpu_to_le32(EROFS_SUPER_MAGIC_V1))
return -1;
IF_FEATURE_BLKID_TYPE(id->type = "erofs");
volume_id_set_label_string(id, sb->volume_name,
MIN(sizeof(sb->volume_name), VOLUME_ID_LABEL_SIZE));
volume_id_set_uuid(id, sb->uuid, UUID_DCE);
return 0;
}
|
