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
  38
  39static int udf_readdir(struct file *file, struct dir_context *ctx)
  40{
  41        struct inode *dir = file_inode(file);
  42        struct udf_inode_info *iinfo = UDF_I(dir);
  43        struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
  44        struct fileIdentDesc *fi = NULL;
  45        struct fileIdentDesc cfi;
  46        udf_pblk_t block, iblock;
  47        loff_t nf_pos;
  48        int flen;
  49        unsigned char *fname = NULL, *copy_name = NULL;
  50        unsigned char *nameptr;
  51        uint16_t liu;
  52        uint8_t lfi;
  53        loff_t size = udf_ext0_offset(dir) + dir->i_size;
  54        struct buffer_head *tmp, *bha[16];
  55        struct kernel_lb_addr eloc;
  56        uint32_t elen;
  57        sector_t offset;
  58        int i, num, ret = 0;
  59        struct extent_position epos = { NULL, 0, {0, 0} };
  60        struct super_block *sb = dir->i_sb;
  61
  62        if (ctx->pos == 0) {
  63                if (!dir_emit_dot(file, ctx))
  64                        return 0;
  65                ctx->pos = 1;
  66        }
  67        nf_pos = (ctx->pos - 1) << 2;
  68        if (nf_pos >= size)
  69                goto out;
  70
  71        fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
  72        if (!fname) {
  73                ret = -ENOMEM;
  74                goto out;
  75        }
  76
  77        if (nf_pos == 0)
  78                nf_pos = udf_ext0_offset(dir);
  79
  80        fibh.soffset = fibh.eoffset = nf_pos & (sb->s_blocksize - 1);
  81        if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
  82                if (inode_bmap(dir, nf_pos >> sb->s_blocksize_bits,
  83                    &epos, &eloc, &elen, &offset)
  84                    != (EXT_RECORDED_ALLOCATED >> 30)) {
  85                        ret = -ENOENT;
  86                        goto out;
  87                }
  88                block = udf_get_lb_pblock(sb, &eloc, offset);
  89                if ((++offset << sb->s_blocksize_bits) < elen) {
  90                        if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  91                                epos.offset -= sizeof(struct short_ad);
  92                        else if (iinfo->i_alloc_type ==
  93                                        ICBTAG_FLAG_AD_LONG)
  94                                epos.offset -= sizeof(struct long_ad);
  95                } else {
  96                        offset = 0;
  97                }
  98
  99                if (!(fibh.sbh = fibh.ebh = udf_tread(sb, block))) {
 100                        ret = -EIO;
 101                        goto out;
 102                }
 103
 104                if (!(offset & ((16 >> (sb->s_blocksize_bits - 9)) - 1))) {
 105                        i = 16 >> (sb->s_blocksize_bits - 9);
 106                        if (i + offset > (elen >> sb->s_blocksize_bits))
 107                                i = (elen >> sb->s_blocksize_bits) - offset;
 108                        for (num = 0; i > 0; i--) {
 109                                block = udf_get_lb_pblock(sb, &eloc, offset + i);
 110                                tmp = udf_tgetblk(sb, block);
 111                                if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
 112                                        bha[num++] = tmp;
 113                                else
 114                                        brelse(tmp);
 115                        }
 116                        if (num) {
 117                                ll_rw_block(REQ_OP_READ, REQ_RAHEAD, num, bha);
 118                                for (i = 0; i < num; i++)
 119                                        brelse(bha[i]);
 120                        }
 121                }
 122        }
 123
 124        while (nf_pos < size) {
 125                struct kernel_lb_addr tloc;
 126
 127                ctx->pos = (nf_pos >> 2) + 1;
 128
 129                fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
 130                                        &elen, &offset);
 131                if (!fi)
 132                        goto out;
 133
 134                liu = le16_to_cpu(cfi.lengthOfImpUse);
 135                lfi = cfi.lengthFileIdent;
 136
 137                if (fibh.sbh == fibh.ebh) {
 138                        nameptr = fi->fileIdent + liu;
 139                } else {
 140                        int poffset;    /* Unpaded ending offset */
 141
 142                        poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
 143
 144                        if (poffset >= lfi) {
 145                                nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 146                        } else {
 147                                if (!copy_name) {
 148                                        copy_name = kmalloc(UDF_NAME_LEN,
 149                                                            GFP_NOFS);
 150                                        if (!copy_name) {
 151                                                ret = -ENOMEM;
 152                                                goto out;
 153                                        }
 154                                }
 155                                nameptr = copy_name;
 156                                memcpy(nameptr, fi->fileIdent + liu,
 157                                       lfi - poffset);
 158                                memcpy(nameptr + lfi - poffset,
 159                                       fibh.ebh->b_data, poffset);
 160                        }
 161                }
 162
 163                if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
 164                        if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
 165                                continue;
 166                }
 167
 168                if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
 169                        if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
 170                                continue;
 171                }
 172
 173                if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
 174                        if (!dir_emit_dotdot(file, ctx))
 175                                goto out;
 176                        continue;
 177                }
 178
 179                flen = udf_get_filename(sb, nameptr, lfi, fname, UDF_NAME_LEN);
 180                if (flen < 0)
 181                        continue;
 182
 183                tloc = lelb_to_cpu(cfi.icb.extLocation);
 184                iblock = udf_get_lb_pblock(sb, &tloc, 0);
 185                if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))
 186                        goto out;
 187        } /* end while */
 188
 189        ctx->pos = (nf_pos >> 2) + 1;
 190
 191out:
 192        if (fibh.sbh != fibh.ebh)
 193                brelse(fibh.ebh);
 194        brelse(fibh.sbh);
 195        brelse(epos.bh);
 196        kfree(fname);
 197        kfree(copy_name);
 198
 199        return ret;
 200}
 201
 202/* readdir and lookup functions */
 203const struct file_operations udf_dir_operations = {
 204        .llseek                 = generic_file_llseek,
 205        .read                   = generic_read_dir,
 206        .iterate_shared         = udf_readdir,
 207        .unlocked_ioctl         = udf_ioctl,
 208        .fsync                  = generic_file_fsync,
 209};
 210