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
  34 #include "udf_i.h"
  35 #include "udf_sb.h"
  36
  37
  38 static 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         int 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, READA, 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 = fi->fileIdent + liu;
 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, fi->fileIdent + liu,
 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
 190 out:
 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 */
 202 const 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 };