![Al Viro](/assets/img/avatar_default.png)
We want to mask lower 5 bits out, not leave only those and clear the rest... As it is, we end up always starting to read from the beginning of directory, no matter what the current position had been. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
292 lines
7.1 KiB
C
292 lines
7.1 KiB
C
/*
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* QNX6 file system, Linux implementation.
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*
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* Version : 1.0.0
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*
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* History :
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*
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* 01-02-2012 by Kai Bankett (chaosman@ontika.net) : first release.
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* 16-02-2012 pagemap extension by Al Viro
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*
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*/
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#include "qnx6.h"
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static unsigned qnx6_lfile_checksum(char *name, unsigned size)
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{
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unsigned crc = 0;
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char *end = name + size;
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while (name < end) {
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crc = ((crc >> 1) + *(name++)) ^
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((crc & 0x00000001) ? 0x80000000 : 0);
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}
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return crc;
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}
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static struct page *qnx6_get_page(struct inode *dir, unsigned long n)
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{
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struct address_space *mapping = dir->i_mapping;
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struct page *page = read_mapping_page(mapping, n, NULL);
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if (!IS_ERR(page))
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kmap(page);
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return page;
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}
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static inline unsigned long dir_pages(struct inode *inode)
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{
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return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
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}
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static unsigned last_entry(struct inode *inode, unsigned long page_nr)
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{
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unsigned long last_byte = inode->i_size;
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last_byte -= page_nr << PAGE_CACHE_SHIFT;
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if (last_byte > PAGE_CACHE_SIZE)
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last_byte = PAGE_CACHE_SIZE;
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return last_byte / QNX6_DIR_ENTRY_SIZE;
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}
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static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,
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struct qnx6_long_dir_entry *de,
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struct page **p)
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{
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struct qnx6_sb_info *sbi = QNX6_SB(sb);
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u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
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u32 n = s >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits); /* in pages */
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/* within page */
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u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_CACHE_MASK;
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struct address_space *mapping = sbi->longfile->i_mapping;
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struct page *page = read_mapping_page(mapping, n, NULL);
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if (IS_ERR(page))
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return ERR_CAST(page);
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kmap(*p = page);
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return (struct qnx6_long_filename *)(page_address(page) + offs);
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}
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static int qnx6_dir_longfilename(struct inode *inode,
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struct qnx6_long_dir_entry *de,
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void *dirent, loff_t pos,
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unsigned de_inode, filldir_t filldir)
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{
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struct qnx6_long_filename *lf;
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struct super_block *s = inode->i_sb;
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struct qnx6_sb_info *sbi = QNX6_SB(s);
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struct page *page;
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int lf_size;
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if (de->de_size != 0xff) {
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/* error - long filename entries always have size 0xff
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in direntry */
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printk(KERN_ERR "qnx6: invalid direntry size (%i).\n",
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de->de_size);
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return 0;
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}
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lf = qnx6_longname(s, de, &page);
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if (IS_ERR(lf)) {
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printk(KERN_ERR "qnx6:Error reading longname\n");
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return 0;
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}
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lf_size = fs16_to_cpu(sbi, lf->lf_size);
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if (lf_size > QNX6_LONG_NAME_MAX) {
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QNX6DEBUG((KERN_INFO "file %s\n", lf->lf_fname));
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printk(KERN_ERR "qnx6:Filename too long (%i)\n", lf_size);
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qnx6_put_page(page);
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return 0;
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}
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/* calc & validate longfilename checksum
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mmi 3g filesystem does not have that checksum */
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if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) !=
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qnx6_lfile_checksum(lf->lf_fname, lf_size))
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printk(KERN_INFO "qnx6: long filename checksum error.\n");
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QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s inode:%u\n",
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lf_size, lf->lf_fname, de_inode));
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if (filldir(dirent, lf->lf_fname, lf_size, pos, de_inode,
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DT_UNKNOWN) < 0) {
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qnx6_put_page(page);
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return 0;
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}
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qnx6_put_page(page);
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/* success */
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return 1;
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}
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static int qnx6_readdir(struct file *filp, void *dirent, filldir_t filldir)
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{
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struct inode *inode = file_inode(filp);
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struct super_block *s = inode->i_sb;
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struct qnx6_sb_info *sbi = QNX6_SB(s);
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loff_t pos = filp->f_pos & ~(QNX6_DIR_ENTRY_SIZE - 1);
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unsigned long npages = dir_pages(inode);
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unsigned long n = pos >> PAGE_CACHE_SHIFT;
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unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE;
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bool done = false;
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if (filp->f_pos >= inode->i_size)
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return 0;
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for ( ; !done && n < npages; n++, start = 0) {
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struct page *page = qnx6_get_page(inode, n);
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int limit = last_entry(inode, n);
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struct qnx6_dir_entry *de;
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int i = start;
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if (IS_ERR(page)) {
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printk(KERN_ERR "qnx6_readdir: read failed\n");
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filp->f_pos = (n + 1) << PAGE_CACHE_SHIFT;
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return PTR_ERR(page);
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}
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de = ((struct qnx6_dir_entry *)page_address(page)) + start;
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for (; i < limit; i++, de++, pos += QNX6_DIR_ENTRY_SIZE) {
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int size = de->de_size;
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u32 no_inode = fs32_to_cpu(sbi, de->de_inode);
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if (!no_inode || !size)
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continue;
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if (size > QNX6_SHORT_NAME_MAX) {
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/* long filename detected
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get the filename from long filename
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structure / block */
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if (!qnx6_dir_longfilename(inode,
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(struct qnx6_long_dir_entry *)de,
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dirent, pos, no_inode,
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filldir)) {
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done = true;
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break;
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}
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} else {
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QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s"
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" inode:%u\n", size, de->de_fname,
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no_inode));
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if (filldir(dirent, de->de_fname, size,
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pos, no_inode, DT_UNKNOWN)
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< 0) {
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done = true;
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break;
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}
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}
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}
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qnx6_put_page(page);
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}
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filp->f_pos = pos;
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return 0;
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}
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/*
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* check if the long filename is correct.
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*/
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static unsigned qnx6_long_match(int len, const char *name,
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struct qnx6_long_dir_entry *de, struct inode *dir)
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{
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struct super_block *s = dir->i_sb;
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struct qnx6_sb_info *sbi = QNX6_SB(s);
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struct page *page;
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int thislen;
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struct qnx6_long_filename *lf = qnx6_longname(s, de, &page);
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if (IS_ERR(lf))
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return 0;
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thislen = fs16_to_cpu(sbi, lf->lf_size);
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if (len != thislen) {
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qnx6_put_page(page);
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return 0;
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}
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if (memcmp(name, lf->lf_fname, len) == 0) {
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qnx6_put_page(page);
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return fs32_to_cpu(sbi, de->de_inode);
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}
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qnx6_put_page(page);
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return 0;
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}
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/*
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* check if the filename is correct.
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*/
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static unsigned qnx6_match(struct super_block *s, int len, const char *name,
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struct qnx6_dir_entry *de)
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{
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struct qnx6_sb_info *sbi = QNX6_SB(s);
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if (memcmp(name, de->de_fname, len) == 0)
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return fs32_to_cpu(sbi, de->de_inode);
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return 0;
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}
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unsigned qnx6_find_entry(int len, struct inode *dir, const char *name,
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struct page **res_page)
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{
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struct super_block *s = dir->i_sb;
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struct qnx6_inode_info *ei = QNX6_I(dir);
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struct page *page = NULL;
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unsigned long start, n;
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unsigned long npages = dir_pages(dir);
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unsigned ino;
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struct qnx6_dir_entry *de;
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struct qnx6_long_dir_entry *lde;
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*res_page = NULL;
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if (npages == 0)
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return 0;
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start = ei->i_dir_start_lookup;
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if (start >= npages)
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start = 0;
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n = start;
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do {
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page = qnx6_get_page(dir, n);
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if (!IS_ERR(page)) {
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int limit = last_entry(dir, n);
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int i;
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de = (struct qnx6_dir_entry *)page_address(page);
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for (i = 0; i < limit; i++, de++) {
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if (len <= QNX6_SHORT_NAME_MAX) {
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/* short filename */
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if (len != de->de_size)
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continue;
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ino = qnx6_match(s, len, name, de);
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if (ino)
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goto found;
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} else if (de->de_size == 0xff) {
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/* deal with long filename */
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lde = (struct qnx6_long_dir_entry *)de;
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ino = qnx6_long_match(len,
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name, lde, dir);
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if (ino)
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goto found;
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} else
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printk(KERN_ERR "qnx6: undefined "
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"filename size in inode.\n");
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}
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qnx6_put_page(page);
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}
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if (++n >= npages)
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n = 0;
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} while (n != start);
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return 0;
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found:
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*res_page = page;
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ei->i_dir_start_lookup = n;
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return ino;
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}
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const struct file_operations qnx6_dir_operations = {
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.llseek = generic_file_llseek,
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.read = generic_read_dir,
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.readdir = qnx6_readdir,
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.fsync = generic_file_fsync,
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};
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const struct inode_operations qnx6_dir_inode_operations = {
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.lookup = qnx6_lookup,
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};
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