283 lines
		
	
	
	
		
			6.5 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			283 lines
		
	
	
	
		
			6.5 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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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@bofh.ai> 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 ((*((unsigned char *) de) - 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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			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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		continue;
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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 = 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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