1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * QNX6 file system, Linux implementation.
4 *
5 * Version : 1.0.0
6 *
7 * History :
8 *
9 * 01-02-2012 by Kai Bankett (chaosman@ontika.net) : first release.
10 *
11 */
12
13 #include <linux/buffer_head.h>
14 #include <linux/slab.h>
15 #include <linux/crc32.h>
16 #include "qnx6.h"
17
18 static void qnx6_mmi_copy_sb(struct qnx6_super_block *qsb,
19 struct qnx6_mmi_super_block *sb)
20 {
21 qsb->sb_magic = sb->sb_magic;
22 qsb->sb_checksum = sb->sb_checksum;
23 qsb->sb_serial = sb->sb_serial;
24 qsb->sb_blocksize = sb->sb_blocksize;
25 qsb->sb_num_inodes = sb->sb_num_inodes;
26 qsb->sb_free_inodes = sb->sb_free_inodes;
27 qsb->sb_num_blocks = sb->sb_num_blocks;
28 qsb->sb_free_blocks = sb->sb_free_blocks;
29
30 /* the rest of the superblock is the same */
31 memcpy(&qsb->Inode, &sb->Inode, sizeof(sb->Inode));
32 memcpy(&qsb->Bitmap, &sb->Bitmap, sizeof(sb->Bitmap));
33 memcpy(&qsb->Longfile, &sb->Longfile, sizeof(sb->Longfile));
34 }
35
36 struct qnx6_super_block *qnx6_mmi_fill_super(struct super_block *s, int silent)
37 {
38 struct buffer_head *bh1, *bh2 = NULL;
39 struct qnx6_mmi_super_block *sb1, *sb2;
40 struct qnx6_super_block *qsb = NULL;
41 struct qnx6_sb_info *sbi;
42 __u64 offset;
43
44 /* Check the superblock signatures
45 start with the first superblock */
46 bh1 = sb_bread(s, 0);
47 if (!bh1) {
48 pr_err("Unable to read first mmi superblock\n");
49 return NULL;
50 }
51 sb1 = (struct qnx6_mmi_super_block *)bh1->b_data;
52 sbi = QNX6_SB(s);
53 if (fs32_to_cpu(sbi, sb1->sb_magic) != QNX6_SUPER_MAGIC) {
54 if (!silent) {
55 pr_err("wrong signature (magic) in superblock #1.\n");
56 goto out;
57 }
58 }
59
60 /* checksum check - start at byte 8 and end at byte 512 */
61 if (fs32_to_cpu(sbi, sb1->sb_checksum) !=
62 crc32_be(0, (char *)(bh1->b_data + 8), 504)) {
63 pr_err("superblock #1 checksum error\n");
64 goto out;
65 }
66
67 /* calculate second superblock blocknumber */
68 offset = fs32_to_cpu(sbi, sb1->sb_num_blocks) + QNX6_SUPERBLOCK_AREA /
69 fs32_to_cpu(sbi, sb1->sb_blocksize);
70
71 /* set new blocksize */
72 if (!sb_set_blocksize(s, fs32_to_cpu(sbi, sb1->sb_blocksize))) {
73 pr_err("unable to set blocksize\n");
74 goto out;
75 }
76 /* blocksize invalidates bh - pull it back in */
77 brelse(bh1);
78 bh1 = sb_bread(s, 0);
79 if (!bh1)
80 goto out;
81 sb1 = (struct qnx6_mmi_super_block *)bh1->b_data;
82
83 /* read second superblock */
84 bh2 = sb_bread(s, offset);
85 if (!bh2) {
86 pr_err("unable to read the second superblock\n");
87 goto out;
88 }
89 sb2 = (struct qnx6_mmi_super_block *)bh2->b_data;
90 if (fs32_to_cpu(sbi, sb2->sb_magic) != QNX6_SUPER_MAGIC) {
91 if (!silent)
92 pr_err("wrong signature (magic) in superblock #2.\n");
93 goto out;
94 }
95
96 /* checksum check - start at byte 8 and end at byte 512 */
97 if (fs32_to_cpu(sbi, sb2->sb_checksum)
98 != crc32_be(0, (char *)(bh2->b_data + 8), 504)) {
99 pr_err("superblock #1 checksum error\n");
100 goto out;
101 }
102
103 qsb = kmalloc(sizeof(*qsb), GFP_KERNEL);
104 if (!qsb) {
105 pr_err("unable to allocate memory.\n");
106 goto out;
107 }
108
109 if (fs64_to_cpu(sbi, sb1->sb_serial) >
110 fs64_to_cpu(sbi, sb2->sb_serial)) {
111 /* superblock #1 active */
112 qnx6_mmi_copy_sb(qsb, sb1);
113 #ifdef CONFIG_QNX6FS_DEBUG
114 qnx6_superblock_debug(qsb, s);
115 #endif
116 memcpy(bh1->b_data, qsb, sizeof(struct qnx6_super_block));
117
118 sbi->sb_buf = bh1;
119 sbi->sb = (struct qnx6_super_block *)bh1->b_data;
120 brelse(bh2);
121 pr_info("superblock #1 active\n");
122 } else {
123 /* superblock #2 active */
124 qnx6_mmi_copy_sb(qsb, sb2);
125 #ifdef CONFIG_QNX6FS_DEBUG
126 qnx6_superblock_debug(qsb, s);
127 #endif
128 memcpy(bh2->b_data, qsb, sizeof(struct qnx6_super_block));
129
130 sbi->sb_buf = bh2;
131 sbi->sb = (struct qnx6_super_block *)bh2->b_data;
132 brelse(bh1);
133 pr_info("superblock #2 active\n");
134 }
135 kfree(qsb);
136
137 /* offset for mmi_fs is just SUPERBLOCK_AREA bytes */
138 sbi->s_blks_off = QNX6_SUPERBLOCK_AREA / s->s_blocksize;
139
140 /* success */
141 return sbi->sb;
142
143 out:
144 if (bh1 != NULL)
145 brelse(bh1);
146 if (bh2 != NULL)
147 brelse(bh2);
148 return NULL;
149 }
150
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