1/*
2 * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
3 *
4 *
5 * HelenOS:
6 * Copyright (c) 2012 Martin Sucha
7 * Copyright (c) 2012 Frantisek Princ
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 *
14 * - Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * - Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * - The name of the author may not be used to endorse or promote products
20 * derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34/** @addtogroup lwext4
35 * @{
36 */
37/**
38 * @file ext4_super.h
39 * @brief Superblock operations.
40 */
41
42#include <ext4_config.h>
43#include <ext4_types.h>
44#include <ext4_misc.h>
45#include <ext4_errno.h>
46#include <ext4_debug.h>
47
48#include <ext4_super.h>
49#include <ext4_crc32.h>
50
51uint32_t ext4_block_group_cnt(struct ext4_sblock *s)
52{
53 uint64_t blocks_count = ext4_sb_get_blocks_cnt(s);
54 uint32_t blocks_per_group = ext4_get32(s, blocks_per_group);
55
56 uint32_t block_groups_count = (uint32_t)(blocks_count / blocks_per_group);
57
58 if (blocks_count % blocks_per_group)
59 block_groups_count++;
60
61 return block_groups_count;
62}
63
64uint32_t ext4_blocks_in_group_cnt(struct ext4_sblock *s, uint32_t bgid)
65{
66 uint32_t block_group_count = ext4_block_group_cnt(s);
67 uint32_t blocks_per_group = ext4_get32(s, blocks_per_group);
68 uint64_t total_blocks = ext4_sb_get_blocks_cnt(s);
69
70 if (bgid < block_group_count - 1)
71 return blocks_per_group;
72
73 return (uint32_t)(total_blocks - ((block_group_count - 1) * blocks_per_group));
74}
75
76uint32_t ext4_inodes_in_group_cnt(struct ext4_sblock *s, uint32_t bgid)
77{
78 uint32_t block_group_count = ext4_block_group_cnt(s);
79 uint32_t inodes_per_group = ext4_get32(s, inodes_per_group);
80 uint32_t total_inodes = ext4_get32(s, inodes_count);
81
82 if (bgid < block_group_count - 1)
83 return inodes_per_group;
84
85 return (total_inodes - ((block_group_count - 1) * inodes_per_group));
86}
87
88#if CONFIG_META_CSUM_ENABLE
89static uint32_t ext4_sb_csum(struct ext4_sblock *s)
90{
91
92 return ext4_crc32c(EXT4_CRC32_INIT, buf: s,
93 offsetof(struct ext4_sblock, checksum));
94}
95#else
96#define ext4_sb_csum(...) 0
97#endif
98
99static bool ext4_sb_verify_csum(struct ext4_sblock *s)
100{
101 if (!ext4_sb_feature_ro_com(s, EXT4_FRO_COM_METADATA_CSUM))
102 return true;
103
104 if (s->checksum_type != to_le32(EXT4_CHECKSUM_CRC32C))
105 return false;
106
107 return s->checksum == to_le32(ext4_sb_csum(s));
108}
109
110static void ext4_sb_set_csum(struct ext4_sblock *s)
111{
112 if (!ext4_sb_feature_ro_com(s, EXT4_FRO_COM_METADATA_CSUM))
113 return;
114
115 s->checksum = to_le32(ext4_sb_csum(s));
116}
117
118int ext4_sb_write(struct ext4_blockdev *bdev, struct ext4_sblock *s)
119{
120 ext4_sb_set_csum(s);
121 return ext4_block_writebytes(bdev, EXT4_SUPERBLOCK_OFFSET, buf: s,
122 EXT4_SUPERBLOCK_SIZE);
123}
124
125int ext4_sb_read(struct ext4_blockdev *bdev, struct ext4_sblock *s)
126{
127 return ext4_block_readbytes(bdev, EXT4_SUPERBLOCK_OFFSET, buf: s,
128 EXT4_SUPERBLOCK_SIZE);
129}
130
131bool ext4_sb_check(struct ext4_sblock *s)
132{
133 if (ext4_get16(s, magic) != EXT4_SUPERBLOCK_MAGIC)
134 return false;
135
136 if (ext4_get32(s, inodes_count) == 0)
137 return false;
138
139 if (ext4_sb_get_blocks_cnt(s) == 0)
140 return false;
141
142 if (ext4_get32(s, blocks_per_group) == 0)
143 return false;
144
145 if (ext4_get32(s, inodes_per_group) == 0)
146 return false;
147
148 if (ext4_get16(s, inode_size) < 128)
149 return false;
150
151 if (ext4_get32(s, first_inode) < 11)
152 return false;
153
154 if (ext4_sb_get_desc_size(s) < EXT4_MIN_BLOCK_GROUP_DESCRIPTOR_SIZE)
155 return false;
156
157 if (ext4_sb_get_desc_size(s) > EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
158 return false;
159
160 if (!ext4_sb_verify_csum(s))
161 return false;
162
163 return true;
164}
165
166static inline int is_power_of(uint32_t a, uint32_t b)
167{
168 while (1) {
169 if (a < b)
170 return 0;
171 if (a == b)
172 return 1;
173 if ((a % b) != 0)
174 return 0;
175 a = a / b;
176 }
177}
178
179bool ext4_sb_sparse(uint32_t group)
180{
181 if (group <= 1)
182 return 1;
183
184 if (!(group & 1))
185 return 0;
186
187 return (is_power_of(a: group, b: 7) || is_power_of(a: group, b: 5) ||
188 is_power_of(a: group, b: 3));
189}
190
191bool ext4_sb_is_super_in_bg(struct ext4_sblock *s, uint32_t group)
192{
193 if (ext4_sb_feature_ro_com(s, EXT4_FRO_COM_SPARSE_SUPER) &&
194 !ext4_sb_sparse(group))
195 return false;
196 return true;
197}
198
199static uint32_t ext4_bg_num_gdb_meta(struct ext4_sblock *s, uint32_t group)
200{
201 uint32_t dsc_per_block =
202 ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
203
204 uint32_t metagroup = group / dsc_per_block;
205 uint32_t first = metagroup * dsc_per_block;
206 uint32_t last = first + dsc_per_block - 1;
207
208 if (group == first || group == first + 1 || group == last)
209 return 1;
210 return 0;
211}
212
213static uint32_t ext4_bg_num_gdb_nometa(struct ext4_sblock *s, uint32_t group)
214{
215 if (!ext4_sb_is_super_in_bg(s, group))
216 return 0;
217 uint32_t dsc_per_block =
218 ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
219
220 uint32_t db_count =
221 (ext4_block_group_cnt(s) + dsc_per_block - 1) / dsc_per_block;
222
223 if (ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG))
224 return ext4_sb_first_meta_bg(s);
225
226 return db_count;
227}
228
229uint32_t ext4_bg_num_gdb(struct ext4_sblock *s, uint32_t group)
230{
231 uint32_t dsc_per_block =
232 ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
233 uint32_t first_meta_bg = ext4_sb_first_meta_bg(s);
234 uint32_t metagroup = group / dsc_per_block;
235
236 if (!ext4_sb_feature_incom(s,EXT4_FINCOM_META_BG) ||
237 metagroup < first_meta_bg)
238 return ext4_bg_num_gdb_nometa(s, group);
239
240 return ext4_bg_num_gdb_meta(s, group);
241}
242
243uint32_t ext4_num_base_meta_clusters(struct ext4_sblock *s,
244 uint32_t block_group)
245{
246 uint32_t num;
247 uint32_t dsc_per_block =
248 ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
249
250 num = ext4_sb_is_super_in_bg(s, group: block_group);
251
252 if (!ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG) ||
253 block_group < ext4_sb_first_meta_bg(s) * dsc_per_block) {
254 if (num) {
255 num += ext4_bg_num_gdb(s, group: block_group);
256 num += ext4_get16(s, s_reserved_gdt_blocks);
257 }
258 } else {
259 num += ext4_bg_num_gdb(s, group: block_group);
260 }
261
262 uint32_t clustersize = 1024 << ext4_get32(s, log_cluster_size);
263 uint32_t cluster_ratio = clustersize / ext4_sb_get_block_size(s);
264 uint32_t v =
265 (num + cluster_ratio - 1) >> ext4_get32(s, log_cluster_size);
266
267 return v;
268}
269
270/**
271 * @}
272 */
273