1 // SPDX-License-Identifier: GPL-2.0+ OR Apache-2.0
2 /*
3 * Created by Li Guifu <blucerlee@gmail.com>
4 */
5 #include <string.h>
6 #include <stdlib.h>
7 #include "erofs/io.h"
8 #include "erofs/print.h"
9 #include "erofs/xattr.h"
10
check_layout_compatibility(struct erofs_sb_info * sbi,struct erofs_super_block * dsb)11 static bool check_layout_compatibility(struct erofs_sb_info *sbi,
12 struct erofs_super_block *dsb)
13 {
14 const unsigned int feature = le32_to_cpu(dsb->feature_incompat);
15
16 sbi->feature_incompat = feature;
17
18 /* check if current kernel meets all mandatory requirements */
19 if (feature & ~EROFS_ALL_FEATURE_INCOMPAT) {
20 erofs_err("unidentified incompatible feature %x, please upgrade kernel version",
21 feature & ~EROFS_ALL_FEATURE_INCOMPAT);
22 return false;
23 }
24 return true;
25 }
26
erofs_init_devices(struct erofs_sb_info * sbi,struct erofs_super_block * dsb)27 static int erofs_init_devices(struct erofs_sb_info *sbi,
28 struct erofs_super_block *dsb)
29 {
30 unsigned int ondisk_extradevs, i;
31 erofs_off_t pos;
32
33 sbi->total_blocks = sbi->primarydevice_blocks;
34
35 if (!erofs_sb_has_device_table(sbi))
36 ondisk_extradevs = 0;
37 else
38 ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
39
40 if (sbi->extra_devices &&
41 ondisk_extradevs != sbi->extra_devices) {
42 erofs_err("extra devices don't match (ondisk %u, given %u)",
43 ondisk_extradevs, sbi->extra_devices);
44 return -EINVAL;
45 }
46 if (!ondisk_extradevs)
47 return 0;
48
49 sbi->extra_devices = ondisk_extradevs;
50 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
51 sbi->devs = calloc(ondisk_extradevs, sizeof(*sbi->devs));
52 if (!sbi->devs)
53 return -ENOMEM;
54 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
55 for (i = 0; i < ondisk_extradevs; ++i) {
56 struct erofs_deviceslot dis;
57 int ret;
58
59 ret = dev_read(sbi, 0, &dis, pos, sizeof(dis));
60 if (ret < 0) {
61 free(sbi->devs);
62 sbi->devs = NULL;
63 return ret;
64 }
65
66 sbi->devs[i].mapped_blkaddr = le32_to_cpu(dis.mapped_blkaddr);
67 sbi->devs[i].blocks = le32_to_cpu(dis.blocks);
68 memcpy(sbi->devs[i].tag, dis.tag, sizeof(dis.tag));
69 sbi->total_blocks += sbi->devs[i].blocks;
70 pos += EROFS_DEVT_SLOT_SIZE;
71 }
72 return 0;
73 }
74
erofs_read_superblock(struct erofs_sb_info * sbi)75 int erofs_read_superblock(struct erofs_sb_info *sbi)
76 {
77 u8 data[EROFS_MAX_BLOCK_SIZE];
78 struct erofs_super_block *dsb;
79 int ret;
80
81 sbi->blkszbits = ilog2(EROFS_MAX_BLOCK_SIZE);
82 ret = blk_read(sbi, 0, data, 0, erofs_blknr(sbi, sizeof(data)));
83 if (ret < 0) {
84 erofs_err("cannot read erofs superblock: %d", ret);
85 return -EIO;
86 }
87 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
88
89 ret = -EINVAL;
90 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
91 erofs_err("cannot find valid erofs superblock");
92 return ret;
93 }
94
95 sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
96
97 sbi->blkszbits = dsb->blkszbits;
98 if (sbi->blkszbits < 9 ||
99 sbi->blkszbits > ilog2(EROFS_MAX_BLOCK_SIZE)) {
100 erofs_err("blksize %llu isn't supported on this platform",
101 erofs_blksiz(sbi) | 0ULL);
102 return ret;
103 } else if (!check_layout_compatibility(sbi, dsb)) {
104 return ret;
105 }
106
107 sbi->primarydevice_blocks = le32_to_cpu(dsb->blocks);
108 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
109 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
110 sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start);
111 sbi->xattr_prefix_count = dsb->xattr_prefix_count;
112 sbi->islotbits = EROFS_ISLOTBITS;
113 sbi->root_nid = le16_to_cpu(dsb->root_nid);
114 sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
115 sbi->inos = le64_to_cpu(dsb->inos);
116 sbi->checksum = le32_to_cpu(dsb->checksum);
117 sbi->extslots = dsb->sb_extslots;
118
119 sbi->build_time = le64_to_cpu(dsb->build_time);
120 sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
121
122 memcpy(&sbi->uuid, dsb->uuid, sizeof(dsb->uuid));
123
124 if (erofs_sb_has_compr_cfgs(sbi))
125 sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
126 else
127 sbi->lz4_max_distance = le16_to_cpu(dsb->u1.lz4_max_distance);
128
129 ret = erofs_init_devices(sbi, dsb);
130 if (ret)
131 return ret;
132
133 ret = erofs_xattr_prefixes_init(sbi);
134 if (ret && sbi->devs) {
135 free(sbi->devs);
136 sbi->devs = NULL;
137 }
138 return ret;
139 }
140
erofs_put_super(struct erofs_sb_info * sbi)141 void erofs_put_super(struct erofs_sb_info *sbi)
142 {
143 if (sbi->devs) {
144 free(sbi->devs);
145 sbi->devs = NULL;
146 }
147 erofs_xattr_prefixes_cleanup(sbi);
148 }
149