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199 |
simons |
/*
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* linux/fs/isofs/namei.c
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*
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* (C) 1992 Eric Youngdale Modified for ISO9660 filesystem.
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*
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* (C) 1991 Linus Torvalds - minix filesystem
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*/
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#include <linux/sched.h>
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#include <linux/iso_fs.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/stat.h>
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#include <linux/fcntl.h>
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#include <asm/segment.h>
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#include <linux/malloc.h>
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#include <linux/errno.h>
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/*
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* ok, we cannot use strncmp, as the name is not in our data space.
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* Thus we'll have to use isofs_match. No big problem. Match also makes
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* some sanity tests.
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*
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* NOTE! unlike strncmp, isofs_match returns 1 for success, 0 for failure.
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*/
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static int isofs_match(int len,const char * name, const char * compare, int dlen)
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{
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if (!compare)
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return 0;
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/* check special "." and ".." files */
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if (dlen == 1) {
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/* "." */
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if (compare[0] == 0) {
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if (!len)
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return 1;
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compare = ".";
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} else if (compare[0] == 1) {
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compare = "..";
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dlen = 2;
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}
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}
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#if 0
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if (len <= 2) printk("Match: %d %d %s %d %d \n",len,dlen,compare,de->name[0], dlen);
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#endif
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if (dlen != len)
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return 0;
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return !memcmp(name, compare, len);
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}
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/*
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* isofs_find_entry()
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*
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* finds an entry in the specified directory with the wanted name. It
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* returns the cache buffer in which the entry was found, and the entry
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* itself (as an inode number). It does NOT read the inode of the
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* entry - you'll have to do that yourself if you want to.
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*/
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static struct buffer_head *
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isofs_find_entry(struct inode * dir, const char * name, int namelen,
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unsigned long * ino, unsigned long * ino_back)
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{
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unsigned long bufsize = ISOFS_BUFFER_SIZE(dir);
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unsigned char bufbits = ISOFS_BUFFER_BITS(dir);
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unsigned int block, i, f_pos, offset, inode_number;
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struct buffer_head * bh;
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void * cpnt = NULL;
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unsigned int old_offset;
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unsigned int backlink;
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int dlen, match;
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char * dpnt;
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unsigned char *page = NULL;
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struct iso_directory_record * de;
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char c;
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*ino = 0;
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if (!dir) return NULL;
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if (!(block = dir->u.isofs_i.i_first_extent)) return NULL;
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f_pos = 0;
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offset = f_pos & (bufsize - 1);
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block = isofs_bmap(dir,f_pos >> bufbits);
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if (!block || !(bh = bread(dir->i_dev,block,bufsize))) return NULL;
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while (f_pos < dir->i_size) {
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de = (struct iso_directory_record *) (bh->b_data + offset);
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backlink = dir->i_ino;
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inode_number = (block << bufbits) + (offset & (bufsize - 1));
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/* If byte is zero, this is the end of file, or time to move to
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the next sector. Usually 2048 byte boundaries. */
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if (*((unsigned char *) de) == 0) {
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brelse(bh);
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offset = 0;
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f_pos = ((f_pos & ~(ISOFS_BLOCK_SIZE - 1))
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+ ISOFS_BLOCK_SIZE);
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block = isofs_bmap(dir,f_pos>>bufbits);
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if (!block || !(bh = bread(dir->i_dev,block,bufsize)))
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return NULL;
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continue; /* Will kick out if past end of directory */
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}
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old_offset = offset;
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offset += *((unsigned char *) de);
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f_pos += *((unsigned char *) de);
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/* Handle case where the directory entry spans two blocks.
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Usually 1024 byte boundaries */
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if (offset >= bufsize) {
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unsigned int frag1;
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frag1 = bufsize - old_offset;
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cpnt = kmalloc(*((unsigned char *) de),GFP_KERNEL);
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if (!cpnt) return NULL;
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memcpy(cpnt, bh->b_data + old_offset, frag1);
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de = (struct iso_directory_record *) cpnt;
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brelse(bh);
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offset = f_pos & (bufsize - 1);
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block = isofs_bmap(dir,f_pos>>bufbits);
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if (!block || !(bh = bread(dir->i_dev,block,bufsize))) {
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kfree(cpnt);
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return NULL;
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};
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memcpy((char *)cpnt+frag1, bh->b_data, offset);
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}
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dlen = de->name_len[0];
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dpnt = de->name;
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/* Handle the '.' case */
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if (*dpnt==0 && dlen==1) {
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inode_number = dir->i_ino;
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backlink = 0;
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}
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/* Handle the '..' case */
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else if (*dpnt==1 && dlen==1) {
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#if 0
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printk("Doing .. (%d %d)",
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dir->i_sb->s_firstdatazone,
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dir->i_ino);
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#endif
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if((dir->i_sb->u.isofs_sb.s_firstdatazone) != dir->i_ino)
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inode_number = dir->u.isofs_i.i_backlink;
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else
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inode_number = dir->i_ino;
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backlink = 0;
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} else {
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if (dir->i_sb->u.isofs_sb.s_rock ||
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dir->i_sb->u.isofs_sb.s_joliet_level) {
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page = (unsigned char *)
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__get_free_page(GFP_KERNEL);
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if (!page) return NULL;
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}
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if (dir->i_sb->u.isofs_sb.s_rock &&
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((i = get_rock_ridge_filename(de, page, dir)))){
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if (i == -1)
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goto out;/* Relocated deep directory */
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dlen = i;
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dpnt = page;
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} else if (dir->i_sb->u.isofs_sb.s_joliet_level) {
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dlen = get_joliet_filename(de, dir, page);
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dpnt = page;
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} else if (dir->i_sb->u.isofs_sb.s_mapping == 'n') {
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for (i = 0; i < dlen; i++) {
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c = dpnt[i];
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/* lower case */
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if (c >= 'A' && c <= 'Z') c |= 0x20;
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if (c == ';' && i == dlen-2 && dpnt[i+1] == '1') {
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dlen -= 2;
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break;
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}
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if (c == ';') c = '.';
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dpnt[i] = c;
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}
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/* This allows us to match with and without
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* a trailing period. */
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if(dpnt[dlen-1] == '.' && namelen == dlen-1)
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dlen--;
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}
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}
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/*
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* Skip hidden or associated files unless unhide is set
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*/
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match = 0;
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if( !(de->flags[-dir->i_sb->u.isofs_sb.s_high_sierra] & 5)
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|| dir->i_sb->u.isofs_sb.s_unhide == 'y' )
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{
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match = isofs_match(namelen,name,dpnt,dlen);
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}
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if (cpnt)
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{
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kfree(cpnt);
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cpnt = NULL;
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}
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if (page) free_page((unsigned long) page);
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if (match) {
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if(inode_number == -1) {
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/* Should only happen for the '..' entry */
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inode_number =
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isofs_lookup_grandparent(dir,
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find_rock_ridge_relocation(de,dir));
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if(inode_number == -1){
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/* Should never happen */
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printk("Backlink not properly set %x %lx.\n",
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isonum_733(de->extent),
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dir->i_ino);
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goto out;
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}
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}
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*ino = inode_number;
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*ino_back = backlink;
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return bh;
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}
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}
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out:
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if (cpnt)
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kfree(cpnt);
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brelse(bh);
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return NULL;
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}
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int isofs_lookup(struct inode * dir,const char * name, int len,
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struct inode ** result)
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{
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unsigned long ino, ino_back;
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struct buffer_head * bh;
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#ifdef DEBUG
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printk("lookup: %x %d\n",dir->i_ino, len);
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#endif
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*result = NULL;
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if (!dir)
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return -ENOENT;
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if (!S_ISDIR(dir->i_mode)) {
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iput(dir);
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return -ENOENT;
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}
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ino = 0;
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if (dcache_lookup(dir, name, len, &ino)) ino_back = dir->i_ino;
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if (!ino) {
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char *lcname;
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/* First try the original name. If that doesn't work and the fs
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* was mounted with check=relaxed, convert the name to lower
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* case and try again.
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*/
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if (!(bh = isofs_find_entry(dir,name,len, &ino, &ino_back))
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&& dir->i_sb->u.isofs_sb.s_name_check == 'r'
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&& (lcname = kmalloc(len, GFP_KERNEL)) != NULL) {
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int i;
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char c;
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for (i=0; i<len; i++) {
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c = name[i];
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if (c >= 'A' && c <= 'Z') c |= 0x20;
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lcname[i] = c;
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}
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bh = isofs_find_entry(dir,lcname,len, &ino, &ino_back);
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kfree(lcname);
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}
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| 277 |
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| 278 |
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if (!bh) {
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iput(dir);
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| 280 |
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return -ENOENT;
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| 281 |
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}
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| 282 |
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if (ino_back == dir->i_ino) {
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| 283 |
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dcache_add(dir, name, len, ino);
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| 284 |
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}
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| 285 |
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brelse(bh);
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| 286 |
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}
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| 287 |
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| 288 |
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if (!(*result = iget(dir->i_sb,ino))) {
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| 289 |
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iput(dir);
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| 290 |
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return -EACCES;
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| 291 |
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}
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| 292 |
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| 293 |
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/* We need this backlink for the ".." entry unless the name that we
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| 294 |
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are looking up traversed a mount point (in which case the inode
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| 295 |
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may not even be on an iso9660 filesystem, and writing to
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| 296 |
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u.isofs_i would only cause memory corruption).
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| 297 |
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*/
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| 298 |
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| 299 |
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if (ino_back && !(*result)->i_pipe && (*result)->i_sb == dir->i_sb) {
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| 300 |
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(*result)->u.isofs_i.i_backlink = ino_back;
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| 301 |
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}
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| 302 |
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| 303 |
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iput(dir);
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| 304 |
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return 0;
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| 305 |
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}
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