linux/fs/udf/dir.c
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   1/*
   2 * dir.c
   3 *
   4 * PURPOSE
   5 *  Directory handling routines for the OSTA-UDF(tm) filesystem.
   6 *
   7 * COPYRIGHT
   8 *      This file is distributed under the terms of the GNU General Public
   9 *      License (GPL). Copies of the GPL can be obtained from:
  10 *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  11 *      Each contributing author retains all rights to their own work.
  12 *
  13 *  (C) 1998-2004 Ben Fennema
  14 *
  15 * HISTORY
  16 *
  17 *  10/05/98 dgb  Split directory operations into its own file
  18 *                Implemented directory reads via do_udf_readdir
  19 *  10/06/98      Made directory operations work!
  20 *  11/17/98      Rewrote directory to support ICBTAG_FLAG_AD_LONG
  21 *  11/25/98 blf  Rewrote directory handling (readdir+lookup) to support reading
  22 *                across blocks.
  23 *  12/12/98      Split out the lookup code to namei.c. bulk of directory
  24 *                code now in directory.c:udf_fileident_read.
  25 */
  26
  27#include "udfdecl.h"
  28
  29#include <linux/string.h>
  30#include <linux/errno.h>
  31#include <linux/mm.h>
  32#include <linux/slab.h>
  33#include <linux/bio.h>
  34
  35#include "udf_i.h"
  36#include "udf_sb.h"
  37
  38static int udf_readdir(struct file *file, struct dir_context *ctx)
  39{
  40        struct inode *dir = file_inode(file);
  41        struct udf_inode_info *iinfo = UDF_I(dir);
  42        struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
  43        struct fileIdentDesc *fi = NULL;
  44        struct fileIdentDesc cfi;
  45        udf_pblk_t block, iblock;
  46        loff_t nf_pos;
  47        int flen;
  48        unsigned char *fname = NULL, *copy_name = NULL;
  49        unsigned char *nameptr;
  50        uint16_t liu;
  51        uint8_t lfi;
  52        loff_t size = udf_ext0_offset(dir) + dir->i_size;
  53        struct buffer_head *tmp, *bha[16];
  54        struct kernel_lb_addr eloc;
  55        uint32_t elen;
  56        sector_t offset;
  57        int i, num, ret = 0;
  58        struct extent_position epos = { NULL, 0, {0, 0} };
  59        struct super_block *sb = dir->i_sb;
  60
  61        if (ctx->pos == 0) {
  62                if (!dir_emit_dot(file, ctx))
  63                        return 0;
  64                ctx->pos = 1;
  65        }
  66        nf_pos = (ctx->pos - 1) << 2;
  67        if (nf_pos >= size)
  68                goto out;
  69
  70        fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
  71        if (!fname) {
  72                ret = -ENOMEM;
  73                goto out;
  74        }
  75
  76        if (nf_pos == 0)
  77                nf_pos = udf_ext0_offset(dir);
  78
  79        fibh.soffset = fibh.eoffset = nf_pos & (sb->s_blocksize - 1);
  80        if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
  81                if (inode_bmap(dir, nf_pos >> sb->s_blocksize_bits,
  82                    &epos, &eloc, &elen, &offset)
  83                    != (EXT_RECORDED_ALLOCATED >> 30)) {
  84                        ret = -ENOENT;
  85                        goto out;
  86                }
  87                block = udf_get_lb_pblock(sb, &eloc, offset);
  88                if ((++offset << sb->s_blocksize_bits) < elen) {
  89                        if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  90                                epos.offset -= sizeof(struct short_ad);
  91                        else if (iinfo->i_alloc_type ==
  92                                        ICBTAG_FLAG_AD_LONG)
  93                                epos.offset -= sizeof(struct long_ad);
  94                } else {
  95                        offset = 0;
  96                }
  97
  98                if (!(fibh.sbh = fibh.ebh = udf_tread(sb, block))) {
  99                        ret = -EIO;
 100                        goto out;
 101                }
 102
 103                if (!(offset & ((16 >> (sb->s_blocksize_bits - 9)) - 1))) {
 104                        i = 16 >> (sb->s_blocksize_bits - 9);
 105                        if (i + offset > (elen >> sb->s_blocksize_bits))
 106                                i = (elen >> sb->s_blocksize_bits) - offset;
 107                        for (num = 0; i > 0; i--) {
 108                                block = udf_get_lb_pblock(sb, &eloc, offset + i);
 109                                tmp = udf_tgetblk(sb, block);
 110                                if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
 111                                        bha[num++] = tmp;
 112                                else
 113                                        brelse(tmp);
 114                        }
 115                        if (num) {
 116                                ll_rw_block(REQ_OP_READ, REQ_RAHEAD, num, bha);
 117                                for (i = 0; i < num; i++)
 118                                        brelse(bha[i]);
 119                        }
 120                }
 121        }
 122
 123        while (nf_pos < size) {
 124                struct kernel_lb_addr tloc;
 125
 126                ctx->pos = (nf_pos >> 2) + 1;
 127
 128                fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
 129                                        &elen, &offset);
 130                if (!fi)
 131                        goto out;
 132
 133                liu = le16_to_cpu(cfi.lengthOfImpUse);
 134                lfi = cfi.lengthFileIdent;
 135
 136                if (fibh.sbh == fibh.ebh) {
 137                        nameptr = udf_get_fi_ident(fi);
 138                } else {
 139                        int poffset;    /* Unpaded ending offset */
 140
 141                        poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
 142
 143                        if (poffset >= lfi) {
 144                                nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 145                        } else {
 146                                if (!copy_name) {
 147                                        copy_name = kmalloc(UDF_NAME_LEN,
 148                                                            GFP_NOFS);
 149                                        if (!copy_name) {
 150                                                ret = -ENOMEM;
 151                                                goto out;
 152                                        }
 153                                }
 154                                nameptr = copy_name;
 155                                memcpy(nameptr, udf_get_fi_ident(fi),
 156                                       lfi - poffset);
 157                                memcpy(nameptr + lfi - poffset,
 158                                       fibh.ebh->b_data, poffset);
 159                        }
 160                }
 161
 162                if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
 163                        if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
 164                                continue;
 165                }
 166
 167                if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
 168                        if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
 169                                continue;
 170                }
 171
 172                if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
 173                        if (!dir_emit_dotdot(file, ctx))
 174                                goto out;
 175                        continue;
 176                }
 177
 178                flen = udf_get_filename(sb, nameptr, lfi, fname, UDF_NAME_LEN);
 179                if (flen < 0)
 180                        continue;
 181
 182                tloc = lelb_to_cpu(cfi.icb.extLocation);
 183                iblock = udf_get_lb_pblock(sb, &tloc, 0);
 184                if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))
 185                        goto out;
 186        } /* end while */
 187
 188        ctx->pos = (nf_pos >> 2) + 1;
 189
 190out:
 191        if (fibh.sbh != fibh.ebh)
 192                brelse(fibh.ebh);
 193        brelse(fibh.sbh);
 194        brelse(epos.bh);
 195        kfree(fname);
 196        kfree(copy_name);
 197
 198        return ret;
 199}
 200
 201/* readdir and lookup functions */
 202const struct file_operations udf_dir_operations = {
 203        .llseek                 = generic_file_llseek,
 204        .read                   = generic_read_dir,
 205        .iterate_shared         = udf_readdir,
 206        .unlocked_ioctl         = udf_ioctl,
 207        .fsync                  = generic_file_fsync,
 208};
 209