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/dir.c b/fs/qnx6/dir.c
new file mode 100644
index 0000000..dc59735
--- /dev/null
+++ b/fs/qnx6/dir.c
@@ -0,0 +1,291 @@
+/*
+ * QNX6 file system, Linux implementation.
+ *
+ * Version : 1.0.0
+ *
+ * History :
+ *
+ * 01-02-2012 by Kai Bankett (chaosman@ontika.net) : first release.
+ * 16-02-2012 pagemap extension by Al Viro
+ *
+ */
+
+#include "qnx6.h"
+
+static unsigned qnx6_lfile_checksum(char *name, unsigned size)
+{
+ unsigned crc = 0;
+ char *end = name + size;
+ while (name < end) {
+ crc = ((crc >> 1) + *(name++)) ^
+ ((crc & 0x00000001) ? 0x80000000 : 0);
+ }
+ return crc;
+}
+
+static struct page *qnx6_get_page(struct inode *dir, unsigned long n)
+{
+ struct address_space *mapping = dir->i_mapping;
+ struct page *page = read_mapping_page(mapping, n, NULL);
+ if (!IS_ERR(page))
+ kmap(page);
+ return page;
+}
+
+static inline unsigned long dir_pages(struct inode *inode)
+{
+ return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
+}
+
+static unsigned last_entry(struct inode *inode, unsigned long page_nr)
+{
+ unsigned long last_byte = inode->i_size;
+ last_byte -= page_nr << PAGE_CACHE_SHIFT;
+ if (last_byte > PAGE_CACHE_SIZE)
+ last_byte = PAGE_CACHE_SIZE;
+ return last_byte / QNX6_DIR_ENTRY_SIZE;
+}
+
+static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,
+ struct qnx6_long_dir_entry *de,
+ struct page **p)
+{
+ struct qnx6_sb_info *sbi = QNX6_SB(sb);
+ u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
+ u32 n = s >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits); /* in pages */
+ /* within page */
+ u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_CACHE_MASK;
+ struct address_space *mapping = sbi->longfile->i_mapping;
+ struct page *page = read_mapping_page(mapping, n, NULL);
+ if (IS_ERR(page))
+ return ERR_CAST(page);
+ kmap(*p = page);
+ return (struct qnx6_long_filename *)(page_address(page) + offs);
+}
+
+static int qnx6_dir_longfilename(struct inode *inode,
+ struct qnx6_long_dir_entry *de,
+ void *dirent, loff_t pos,
+ unsigned de_inode, filldir_t filldir)
+{
+ struct qnx6_long_filename *lf;
+ struct super_block *s = inode->i_sb;
+ struct qnx6_sb_info *sbi = QNX6_SB(s);
+ struct page *page;
+ int lf_size;
+
+ if (de->de_size != 0xff) {
+ /* error - long filename entries always have size 0xff
+ in direntry */
+ printk(KERN_ERR "qnx6: invalid direntry size (%i).\n",
+ de->de_size);
+ return 0;
+ }
+ lf = qnx6_longname(s, de, &page);
+ if (IS_ERR(lf)) {
+ printk(KERN_ERR "qnx6:Error reading longname\n");
+ return 0;
+ }
+
+ lf_size = fs16_to_cpu(sbi, lf->lf_size);
+
+ if (lf_size > QNX6_LONG_NAME_MAX) {
+ QNX6DEBUG((KERN_INFO "file %s\n", lf->lf_fname));
+ printk(KERN_ERR "qnx6:Filename too long (%i)\n", lf_size);
+ qnx6_put_page(page);
+ return 0;
+ }
+
+ /* calc & validate longfilename checksum
+ mmi 3g filesystem does not have that checksum */
+ if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) !=
+ qnx6_lfile_checksum(lf->lf_fname, lf_size))
+ printk(KERN_INFO "qnx6: long filename checksum error.\n");
+
+ QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s inode:%u\n",
+ lf_size, lf->lf_fname, de_inode));
+ if (filldir(dirent, lf->lf_fname, lf_size, pos, de_inode,
+ DT_UNKNOWN) < 0) {
+ qnx6_put_page(page);
+ return 0;
+ }
+
+ qnx6_put_page(page);
+ /* success */
+ return 1;
+}
+
+static int qnx6_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ struct super_block *s = inode->i_sb;
+ struct qnx6_sb_info *sbi = QNX6_SB(s);
+ loff_t pos = filp->f_pos & (QNX6_DIR_ENTRY_SIZE - 1);
+ unsigned long npages = dir_pages(inode);
+ unsigned long n = pos >> PAGE_CACHE_SHIFT;
+ unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE;
+ bool done = false;
+
+ if (filp->f_pos >= inode->i_size)
+ return 0;
+
+ for ( ; !done && n < npages; n++, start = 0) {
+ struct page *page = qnx6_get_page(inode, n);
+ int limit = last_entry(inode, n);
+ struct qnx6_dir_entry *de;
+ int i = start;
+
+ if (IS_ERR(page)) {
+ printk(KERN_ERR "qnx6_readdir: read failed\n");
+ filp->f_pos = (n + 1) << PAGE_CACHE_SHIFT;
+ return PTR_ERR(page);
+ }
+ de = ((struct qnx6_dir_entry *)page_address(page)) + start;
+ for (; i < limit; i++, de++, pos += QNX6_DIR_ENTRY_SIZE) {
+ int size = de->de_size;
+ u32 no_inode = fs32_to_cpu(sbi, de->de_inode);
+
+ if (!no_inode || !size)
+ continue;
+
+ if (size > QNX6_SHORT_NAME_MAX) {
+ /* long filename detected
+ get the filename from long filename
+ structure / block */
+ if (!qnx6_dir_longfilename(inode,
+ (struct qnx6_long_dir_entry *)de,
+ dirent, pos, no_inode,
+ filldir)) {
+ done = true;
+ break;
+ }
+ } else {
+ QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s"
+ " inode:%u\n", size, de->de_fname,
+ no_inode));
+ if (filldir(dirent, de->de_fname, size,
+ pos, no_inode, DT_UNKNOWN)
+ < 0) {
+ done = true;
+ break;
+ }
+ }
+ }
+ qnx6_put_page(page);
+ }
+ filp->f_pos = pos;
+ return 0;
+}
+
+/*
+ * check if the long filename is correct.
+ */
+static unsigned qnx6_long_match(int len, const char *name,
+ struct qnx6_long_dir_entry *de, struct inode *dir)
+{
+ struct super_block *s = dir->i_sb;
+ struct qnx6_sb_info *sbi = QNX6_SB(s);
+ struct page *page;
+ int thislen;
+ struct qnx6_long_filename *lf = qnx6_longname(s, de, &page);
+
+ if (IS_ERR(lf))
+ return 0;
+
+ thislen = fs16_to_cpu(sbi, lf->lf_size);
+ if (len != thislen) {
+ qnx6_put_page(page);
+ return 0;
+ }
+ if (memcmp(name, lf->lf_fname, len) == 0) {
+ qnx6_put_page(page);
+ return fs32_to_cpu(sbi, de->de_inode);
+ }
+ qnx6_put_page(page);
+ return 0;
+}
+
+/*
+ * check if the filename is correct.
+ */
+static unsigned qnx6_match(struct super_block *s, int len, const char *name,
+ struct qnx6_dir_entry *de)
+{
+ struct qnx6_sb_info *sbi = QNX6_SB(s);
+ if (memcmp(name, de->de_fname, len) == 0)
+ return fs32_to_cpu(sbi, de->de_inode);
+ return 0;
+}
+
+
+unsigned qnx6_find_entry(int len, struct inode *dir, const char *name,
+ struct page **res_page)
+{
+ struct super_block *s = dir->i_sb;
+ struct qnx6_inode_info *ei = QNX6_I(dir);
+ struct page *page = NULL;
+ unsigned long start, n;
+ unsigned long npages = dir_pages(dir);
+ unsigned ino;
+ struct qnx6_dir_entry *de;
+ struct qnx6_long_dir_entry *lde;
+
+ *res_page = NULL;
+
+ if (npages == 0)
+ return 0;
+ start = ei->i_dir_start_lookup;
+ if (start >= npages)
+ start = 0;
+ n = start;
+
+ do {
+ page = qnx6_get_page(dir, n);
+ if (!IS_ERR(page)) {
+ int limit = last_entry(dir, n);
+ int i;
+
+ de = (struct qnx6_dir_entry *)page_address(page);
+ for (i = 0; i < limit; i++, de++) {
+ if (len <= QNX6_SHORT_NAME_MAX) {
+ /* short filename */
+ if (len != de->de_size)
+ continue;
+ ino = qnx6_match(s, len, name, de);
+ if (ino)
+ goto found;
+ } else if (de->de_size == 0xff) {
+ /* deal with long filename */
+ lde = (struct qnx6_long_dir_entry *)de;
+ ino = qnx6_long_match(len,
+ name, lde, dir);
+ if (ino)
+ goto found;
+ } else
+ printk(KERN_ERR "qnx6: undefined "
+ "filename size in inode.\n");
+ }
+ qnx6_put_page(page);
+ }
+
+ if (++n >= npages)
+ n = 0;
+ } while (n != start);
+ return 0;
+
+found:
+ *res_page = page;
+ ei->i_dir_start_lookup = n;
+ return ino;
+}
+
+const struct file_operations qnx6_dir_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .readdir = qnx6_readdir,
+ .fsync = generic_file_fsync,
+};
+
+const struct inode_operations qnx6_dir_inode_operations = {
+ .lookup = qnx6_lookup,
+};