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