fs: initial qnx6fs addition
Adds support for qnx6fs readonly support to the linux kernel.
* Mount option
The option mmi_fs can be used to mount Harman Becker/Audi MMI 3G
HDD qnx6fs filesystems.
* Documentation
A high level filesystem stucture description can be found in the
Documentation/filesystems directory. (qnx6.txt)
* Additional features
- Active (stable) superblock selection
- Superblock checksum check (enforced)
- Supports mount of qnx6 filesystems with to host different endianess
- Automatic endianess detection
- Longfilename support (with non-enfocing crc check)
- All blocksizes (512, 1024, 2048 and 4096 supported)
Signed-off-by: Kai Bankett <chaosman@ontika.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/qnx6/super_mmi.c b/fs/qnx6/super_mmi.c
new file mode 100644
index 0000000..29c32cb
--- /dev/null
+++ b/fs/qnx6/super_mmi.c
@@ -0,0 +1,150 @@
+/*
+ * QNX6 file system, Linux implementation.
+ *
+ * Version : 1.0.0
+ *
+ * History :
+ *
+ * 01-02-2012 by Kai Bankett (chaosman@ontika.net) : first release.
+ *
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/slab.h>
+#include <linux/crc32.h>
+#include "qnx6.h"
+
+static void qnx6_mmi_copy_sb(struct qnx6_super_block *qsb,
+ struct qnx6_mmi_super_block *sb)
+{
+ qsb->sb_magic = sb->sb_magic;
+ qsb->sb_checksum = sb->sb_checksum;
+ qsb->sb_serial = sb->sb_serial;
+ qsb->sb_blocksize = sb->sb_blocksize;
+ qsb->sb_num_inodes = sb->sb_num_inodes;
+ qsb->sb_free_inodes = sb->sb_free_inodes;
+ qsb->sb_num_blocks = sb->sb_num_blocks;
+ qsb->sb_free_blocks = sb->sb_free_blocks;
+
+ /* the rest of the superblock is the same */
+ memcpy(&qsb->Inode, &sb->Inode, sizeof(sb->Inode));
+ memcpy(&qsb->Bitmap, &sb->Bitmap, sizeof(sb->Bitmap));
+ memcpy(&qsb->Longfile, &sb->Longfile, sizeof(sb->Longfile));
+}
+
+struct qnx6_super_block *qnx6_mmi_fill_super(struct super_block *s, int silent)
+{
+ struct buffer_head *bh1, *bh2 = NULL;
+ struct qnx6_mmi_super_block *sb1, *sb2;
+ struct qnx6_super_block *qsb = NULL;
+ struct qnx6_sb_info *sbi;
+ __u64 offset;
+
+ /* Check the superblock signatures
+ start with the first superblock */
+ bh1 = sb_bread(s, 0);
+ if (!bh1) {
+ printk(KERN_ERR "qnx6: Unable to read first mmi superblock\n");
+ return NULL;
+ }
+ sb1 = (struct qnx6_mmi_super_block *)bh1->b_data;
+ sbi = QNX6_SB(s);
+ if (fs32_to_cpu(sbi, sb1->sb_magic) != QNX6_SUPER_MAGIC) {
+ if (!silent) {
+ printk(KERN_ERR "qnx6: wrong signature (magic) in"
+ " superblock #1.\n");
+ goto out;
+ }
+ }
+
+ /* checksum check - start at byte 8 and end at byte 512 */
+ if (fs32_to_cpu(sbi, sb1->sb_checksum) !=
+ crc32_be(0, (char *)(bh1->b_data + 8), 504)) {
+ printk(KERN_ERR "qnx6: superblock #1 checksum error\n");
+ goto out;
+ }
+
+ /* calculate second superblock blocknumber */
+ offset = fs32_to_cpu(sbi, sb1->sb_num_blocks) + QNX6_SUPERBLOCK_AREA /
+ fs32_to_cpu(sbi, sb1->sb_blocksize);
+
+ /* set new blocksize */
+ if (!sb_set_blocksize(s, fs32_to_cpu(sbi, sb1->sb_blocksize))) {
+ printk(KERN_ERR "qnx6: unable to set blocksize\n");
+ goto out;
+ }
+ /* blocksize invalidates bh - pull it back in */
+ brelse(bh1);
+ bh1 = sb_bread(s, 0);
+ if (!bh1)
+ goto out;
+ sb1 = (struct qnx6_mmi_super_block *)bh1->b_data;
+
+ /* read second superblock */
+ bh2 = sb_bread(s, offset);
+ if (!bh2) {
+ printk(KERN_ERR "qnx6: unable to read the second superblock\n");
+ goto out;
+ }
+ sb2 = (struct qnx6_mmi_super_block *)bh2->b_data;
+ if (fs32_to_cpu(sbi, sb2->sb_magic) != QNX6_SUPER_MAGIC) {
+ if (!silent)
+ printk(KERN_ERR "qnx6: wrong signature (magic) in"
+ " superblock #2.\n");
+ goto out;
+ }
+
+ /* checksum check - start at byte 8 and end at byte 512 */
+ if (fs32_to_cpu(sbi, sb2->sb_checksum)
+ != crc32_be(0, (char *)(bh2->b_data + 8), 504)) {
+ printk(KERN_ERR "qnx6: superblock #1 checksum error\n");
+ goto out;
+ }
+
+ qsb = kmalloc(sizeof(*qsb), GFP_KERNEL);
+ if (!qsb) {
+ printk(KERN_ERR "qnx6: unable to allocate memory.\n");
+ goto out;
+ }
+
+ if (fs64_to_cpu(sbi, sb1->sb_serial) >
+ fs64_to_cpu(sbi, sb2->sb_serial)) {
+ /* superblock #1 active */
+ qnx6_mmi_copy_sb(qsb, sb1);
+#ifdef CONFIG_QNX6FS_DEBUG
+ qnx6_superblock_debug(qsb, s);
+#endif
+ memcpy(bh1->b_data, qsb, sizeof(struct qnx6_super_block));
+
+ sbi->sb_buf = bh1;
+ sbi->sb = (struct qnx6_super_block *)bh1->b_data;
+ brelse(bh2);
+ printk(KERN_INFO "qnx6: superblock #1 active\n");
+ } else {
+ /* superblock #2 active */
+ qnx6_mmi_copy_sb(qsb, sb2);
+#ifdef CONFIG_QNX6FS_DEBUG
+ qnx6_superblock_debug(qsb, s);
+#endif
+ memcpy(bh2->b_data, qsb, sizeof(struct qnx6_super_block));
+
+ sbi->sb_buf = bh2;
+ sbi->sb = (struct qnx6_super_block *)bh2->b_data;
+ brelse(bh1);
+ printk(KERN_INFO "qnx6: superblock #2 active\n");
+ }
+ kfree(qsb);
+
+ /* offset for mmi_fs is just SUPERBLOCK_AREA bytes */
+ sbi->s_blks_off = QNX6_SUPERBLOCK_AREA / s->s_blocksize;
+
+ /* success */
+ return sbi->sb;
+
+out:
+ if (bh1 != NULL)
+ brelse(bh1);
+ if (bh2 != NULL)
+ brelse(bh2);
+ return NULL;
+}