GNU Linux-libre 4.19.211-gnu1
[releases.git] / fs / qnx6 / super_mmi.c
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 }