284 lines
6.5 KiB
C
284 lines
6.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/isofs/dir.c
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*
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* (C) 1992, 1993, 1994 Eric Youngdale Modified for ISO 9660 filesystem.
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*
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* (C) 1991 Linus Torvalds - minix filesystem
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*
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* Steve Beynon : Missing last directory entries fixed
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* (stephen@askone.demon.co.uk) : 21st June 1996
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*
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* isofs directory handling functions
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*/
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#include <linux/gfp.h>
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#include "isofs.h"
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int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode)
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{
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char * old = de->name;
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int len = de->name_len[0];
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int i;
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for (i = 0; i < len; i++) {
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unsigned char c = old[i];
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if (!c)
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break;
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if (c >= 'A' && c <= 'Z')
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c |= 0x20; /* lower case */
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/* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
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if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
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break;
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/* Drop trailing ';1' */
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if (c == ';' && i == len - 2 && old[i + 1] == '1')
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break;
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/* Convert remaining ';' to '.' */
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/* Also '/' to '.' (broken Acorn-generated ISO9660 images) */
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if (c == ';' || c == '/')
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c = '.';
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new[i] = c;
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}
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return i;
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}
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/* Acorn extensions written by Matthew Wilcox <willy@infradead.org> 1998 */
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int get_acorn_filename(struct iso_directory_record *de,
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char *retname, struct inode *inode)
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{
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int std;
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unsigned char *chr;
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int retnamlen = isofs_name_translate(de, retname, inode);
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if (retnamlen == 0)
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return 0;
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std = sizeof(struct iso_directory_record) + de->name_len[0];
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if (std & 1)
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std++;
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if (de->length[0] - std != 32)
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return retnamlen;
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chr = ((unsigned char *) de) + std;
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if (strncmp(chr, "ARCHIMEDES", 10))
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return retnamlen;
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if ((*retname == '_') && ((chr[19] & 1) == 1))
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*retname = '!';
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if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
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&& ((chr[12] & 0xf0) == 0xf0)) {
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retname[retnamlen] = ',';
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sprintf(retname+retnamlen+1, "%3.3x",
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((chr[12] & 0xf) << 8) | chr[11]);
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retnamlen += 4;
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}
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return retnamlen;
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}
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/*
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* This should _really_ be cleaned up some day..
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*/
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static int do_isofs_readdir(struct inode *inode, struct file *file,
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struct dir_context *ctx,
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char *tmpname, struct iso_directory_record *tmpde)
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{
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unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
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unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
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unsigned long block, offset, block_saved, offset_saved;
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unsigned long inode_number = 0; /* Quiet GCC */
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struct buffer_head *bh = NULL;
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int len;
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int map;
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int first_de = 1;
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char *p = NULL; /* Quiet GCC */
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struct iso_directory_record *de;
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struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
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offset = ctx->pos & (bufsize - 1);
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block = ctx->pos >> bufbits;
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while (ctx->pos < inode->i_size) {
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int de_len;
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if (!bh) {
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bh = isofs_bread(inode, block);
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if (!bh)
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return 0;
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}
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de = (struct iso_directory_record *) (bh->b_data + offset);
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de_len = *(unsigned char *)de;
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/*
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* If the length byte is zero, we should move on to the next
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* CDROM sector. If we are at the end of the directory, we
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* kick out of the while loop.
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*/
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if (de_len == 0) {
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brelse(bh);
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bh = NULL;
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ctx->pos = (ctx->pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
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block = ctx->pos >> bufbits;
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offset = 0;
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continue;
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}
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block_saved = block;
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offset_saved = offset;
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offset += de_len;
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/* Make sure we have a full directory entry */
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if (offset >= bufsize) {
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int slop = bufsize - offset + de_len;
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memcpy(tmpde, de, slop);
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offset &= bufsize - 1;
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block++;
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brelse(bh);
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bh = NULL;
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if (offset) {
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bh = isofs_bread(inode, block);
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if (!bh)
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return 0;
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memcpy((void *) tmpde + slop, bh->b_data, offset);
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}
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de = tmpde;
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}
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/* Basic sanity check, whether name doesn't exceed dir entry */
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if (de_len < de->name_len[0] +
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sizeof(struct iso_directory_record)) {
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printk(KERN_NOTICE "iso9660: Corrupted directory entry"
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" in block %lu of inode %lu\n", block,
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inode->i_ino);
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brelse(bh);
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return -EIO;
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}
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if (first_de) {
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isofs_normalize_block_and_offset(de,
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&block_saved,
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&offset_saved);
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inode_number = isofs_get_ino(block_saved,
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offset_saved, bufbits);
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}
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if (de->flags[-sbi->s_high_sierra] & 0x80) {
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first_de = 0;
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ctx->pos += de_len;
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continue;
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}
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first_de = 1;
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/* Handle the case of the '.' directory */
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if (de->name_len[0] == 1 && de->name[0] == 0) {
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if (!dir_emit_dot(file, ctx))
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break;
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ctx->pos += de_len;
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continue;
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}
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len = 0;
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/* Handle the case of the '..' directory */
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if (de->name_len[0] == 1 && de->name[0] == 1) {
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if (!dir_emit_dotdot(file, ctx))
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break;
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ctx->pos += de_len;
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continue;
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}
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/* Handle everything else. Do name translation if there
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is no Rock Ridge NM field. */
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/*
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* Do not report hidden files if so instructed, or associated
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* files unless instructed to do so
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*/
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if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
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(!sbi->s_showassoc &&
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(de->flags[-sbi->s_high_sierra] & 4))) {
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ctx->pos += de_len;
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continue;
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}
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map = 1;
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if (sbi->s_rock) {
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len = get_rock_ridge_filename(de, tmpname, inode);
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if (len != 0) { /* may be -1 */
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p = tmpname;
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map = 0;
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}
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}
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if (map) {
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#ifdef CONFIG_JOLIET
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if (sbi->s_joliet_level) {
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len = get_joliet_filename(de, tmpname, inode);
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p = tmpname;
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} else
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#endif
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if (sbi->s_mapping == 'a') {
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len = get_acorn_filename(de, tmpname, inode);
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p = tmpname;
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} else
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if (sbi->s_mapping == 'n') {
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len = isofs_name_translate(de, tmpname, inode);
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p = tmpname;
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} else {
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p = de->name;
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len = de->name_len[0];
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}
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}
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if (len > 0) {
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if (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN))
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break;
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}
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ctx->pos += de_len;
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}
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if (bh)
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brelse(bh);
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return 0;
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}
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/*
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* Handle allocation of temporary space for name translation and
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* handling split directory entries.. The real work is done by
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* "do_isofs_readdir()".
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*/
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static int isofs_readdir(struct file *file, struct dir_context *ctx)
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{
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int result;
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char *tmpname;
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struct iso_directory_record *tmpde;
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struct inode *inode = file_inode(file);
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tmpname = (char *)__get_free_page(GFP_KERNEL);
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if (tmpname == NULL)
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return -ENOMEM;
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tmpde = (struct iso_directory_record *) (tmpname+1024);
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result = do_isofs_readdir(inode, file, ctx, tmpname, tmpde);
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free_page((unsigned long) tmpname);
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return result;
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}
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const struct file_operations isofs_dir_operations =
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{
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.llseek = generic_file_llseek,
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.read = generic_read_dir,
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.iterate_shared = isofs_readdir,
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};
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/*
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* directories can handle most operations...
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*/
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const struct inode_operations isofs_dir_inode_operations =
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{
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.lookup = isofs_lookup,
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};
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