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285 lines
6.5 KiB
285 lines
6.5 KiB
// 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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* ([email protected]) : 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 <[email protected]> 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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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_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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