fs/udf/dir.c

   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
  39 static 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         int 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
 191 out:
 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 */
 203 const 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 };