LXR linux/fs/qnx6/super

   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
  18static 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
  36struct 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
 143out:
 144        if (bh1 != NULL)
 145                brelse(bh1);
 146        if (bh2 != NULL)
 147                brelse(bh2);
 148        return NULL;
 149}
 150