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/buffer_head.h>
  34
  35#include "udf_i.h"
  36#include "udf_sb.h"
  37
  38static int do_udf_readdir(struct inode *dir, struct file *filp,
  39                          filldir_t filldir, void *dirent)
  40{
  41        struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
  42        struct fileIdentDesc *fi = NULL;
  43        struct fileIdentDesc cfi;
  44        int block, iblock;
  45        loff_t nf_pos = (filp->f_pos - 1) << 2;
  46        int flen;
  47        unsigned char *fname = NULL;
  48        unsigned char *nameptr;
  49        uint16_t liu;
  50        uint8_t lfi;
  51        loff_t size = udf_ext0_offset(dir) + dir->i_size;
  52        struct buffer_head *tmp, *bha[16];
  53        struct kernel_lb_addr eloc;
  54        uint32_t elen;
  55        sector_t offset;
  56        int i, num, ret = 0;
  57        unsigned int dt_type;
  58        struct extent_position epos = { NULL, 0, {0, 0} };
  59        struct udf_inode_info *iinfo;
  60
  61        if (nf_pos >= size)
  62                goto out;
  63
  64        fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
  65        if (!fname) {
  66                ret = -ENOMEM;
  67                goto out;
  68        }
  69
  70        if (nf_pos == 0)
  71                nf_pos = udf_ext0_offset(dir);
  72
  73        fibh.soffset = fibh.eoffset = nf_pos & (dir->i_sb->s_blocksize - 1);
  74        iinfo = UDF_I(dir);
  75        if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
  76                if (inode_bmap(dir, nf_pos >> dir->i_sb->s_blocksize_bits,
  77                    &epos, &eloc, &elen, &offset)
  78                    != (EXT_RECORDED_ALLOCATED >> 30)) {
  79                        ret = -ENOENT;
  80                        goto out;
  81                }
  82                block = udf_get_lb_pblock(dir->i_sb, &eloc, offset);
  83                if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
  84                        if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  85                                epos.offset -= sizeof(struct short_ad);
  86                        else if (iinfo->i_alloc_type ==
  87                                        ICBTAG_FLAG_AD_LONG)
  88                                epos.offset -= sizeof(struct long_ad);
  89                } else {
  90                        offset = 0;
  91                }
  92
  93                if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block))) {
  94                        ret = -EIO;
  95                        goto out;
  96                }
  97
  98                if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1))) {
  99                        i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
 100                        if (i + offset > (elen >> dir->i_sb->s_blocksize_bits))
 101                                i = (elen >> dir->i_sb->s_blocksize_bits) - offset;
 102                        for (num = 0; i > 0; i--) {
 103                                block = udf_get_lb_pblock(dir->i_sb, &eloc, offset + i);
 104                                tmp = udf_tgetblk(dir->i_sb, block);
 105                                if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
 106                                        bha[num++] = tmp;
 107                                else
 108                                        brelse(tmp);
 109                        }
 110                        if (num) {
 111                                ll_rw_block(READA, num, bha);
 112                                for (i = 0; i < num; i++)
 113                                        brelse(bha[i]);
 114                        }
 115                }
 116        }
 117
 118        while (nf_pos < size) {
 119                filp->f_pos = (nf_pos >> 2) + 1;
 120
 121                fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
 122                                        &elen, &offset);
 123                if (!fi)
 124                        goto out;
 125
 126                liu = le16_to_cpu(cfi.lengthOfImpUse);
 127                lfi = cfi.lengthFileIdent;
 128
 129                if (fibh.sbh == fibh.ebh) {
 130                        nameptr = fi->fileIdent + liu;
 131                } else {
 132                        int poffset;    /* Unpaded ending offset */
 133
 134                        poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
 135
 136                        if (poffset >= lfi) {
 137                                nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 138                        } else {
 139                                nameptr = fname;
 140                                memcpy(nameptr, fi->fileIdent + liu,
 141                                       lfi - poffset);
 142                                memcpy(nameptr + lfi - poffset,
 143                                       fibh.ebh->b_data, poffset);
 144                        }
 145                }
 146
 147                if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
 148                        if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE))
 149                                continue;
 150                }
 151
 152                if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
 153                        if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE))
 154                                continue;
 155                }
 156
 157                if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
 158                        iblock = parent_ino(filp->f_path.dentry);
 159                        flen = 2;
 160                        memcpy(fname, "..", flen);
 161                        dt_type = DT_DIR;
 162                } else {
 163                        struct kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
 164
 165                        iblock = udf_get_lb_pblock(dir->i_sb, &tloc, 0);
 166                        flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
 167                        dt_type = DT_UNKNOWN;
 168                }
 169
 170                if (flen && filldir(dirent, fname, flen, filp->f_pos,
 171                                    iblock, dt_type) < 0)
 172                        goto out;
 173        } /* end while */
 174
 175        filp->f_pos = (nf_pos >> 2) + 1;
 176
 177out:
 178        if (fibh.sbh != fibh.ebh)
 179                brelse(fibh.ebh);
 180        brelse(fibh.sbh);
 181        brelse(epos.bh);
 182        kfree(fname);
 183
 184        return ret;
 185}
 186
 187static int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
 188{
 189        struct inode *dir = filp->f_path.dentry->d_inode;
 190        int result;
 191
 192        if (filp->f_pos == 0) {
 193                if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) < 0) {
 194                        return 0;
 195                }
 196                filp->f_pos++;
 197        }
 198
 199        result = do_udf_readdir(dir, filp, filldir, dirent);
 200        return result;
 201}
 202
 203/* readdir and lookup functions */
 204const struct file_operations udf_dir_operations = {
 205        .llseek                 = generic_file_llseek,
 206        .read                   = generic_read_dir,
 207        .readdir                = udf_readdir,
 208        .unlocked_ioctl         = udf_ioctl,
 209        .fsync                  = generic_file_fsync,
 210};
 211
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