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