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/smp_lock.h>
  34 #include <linux/buffer_head.h>
  35
  36 #include "udf_i.h"
  37 #include "udf_sb.h"
  38
  39 /* Prototypes for file operations */
  40 static int udf_readdir(struct file *, void *, filldir_t);
  41 static int do_udf_readdir(struct inode *, struct file *, filldir_t, void *);
  42
  43 /* readdir and lookup functions */
  44
  45 struct file_operations udf_dir_operations = {
  46         .read                   = generic_read_dir,
  47         .readdir                = udf_readdir,
  48         .ioctl                  = udf_ioctl,
  49         .fsync                  = udf_fsync_file,
  50 };
  51
  52 /*
  53  * udf_readdir
  54  *
  55  * PURPOSE
  56  *      Read a directory entry.
  57  *
  58  * DESCRIPTION
  59  *      Optional - sys_getdents() will return -ENOTDIR if this routine is not
  60  *      available.
  61  *
  62  *      Refer to sys_getdents() in fs/readdir.c
  63  *      sys_getdents() -> .
  64  *
  65  * PRE-CONDITIONS
  66  *      filp                    Pointer to directory file.
  67  *      buf                     Pointer to directory entry buffer.
  68  *      filldir                 Pointer to filldir function.
  69  *
  70  * POST-CONDITIONS
  71  *      <return>                >=0 on success.
  72  *
  73  * HISTORY
  74  *      July 1, 1997 - Andrew E. Mileski
  75  *      Written, tested, and released.
  76  */
  77
  78 int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
  79 {
  80         struct inode *dir = filp->f_dentry->d_inode;
  81         int result;
  82
  83         lock_kernel();
  84
  85         if ( filp->f_pos == 0 )
  86         {
  87                 if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) < 0)
  88                 {
  89                         unlock_kernel();
  90                         return 0;
  91                 }
  92                 filp->f_pos ++;
  93         }
  94
  95         result = do_udf_readdir(dir, filp, filldir, dirent);
  96         unlock_kernel();
  97         return result;
  98 }
  99
 100 static int
 101 do_udf_readdir(struct inode * dir, struct file *filp, filldir_t filldir, void *dirent)
 102 {
 103         struct udf_fileident_bh fibh;
 104         struct fileIdentDesc *fi=NULL;
 105         struct fileIdentDesc cfi;
 106         int block, iblock;
 107         loff_t nf_pos = filp->f_pos - 1;
 108         int flen;
 109         char fname[UDF_NAME_LEN];
 110         char *nameptr;
 111         uint16_t liu;
 112         uint8_t lfi;
 113         loff_t size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
 114         struct buffer_head * bh = NULL, * tmp, * bha[16];
 115         kernel_lb_addr bloc, eloc;
 116         uint32_t extoffset, elen, offset;
 117         int i, num;
 118         unsigned int dt_type;
 119
 120         if (nf_pos >= size)
 121                 return 0;
 122
 123         if (nf_pos == 0)
 124                 nf_pos = (udf_ext0_offset(dir) >> 2);
 125
 126         fibh.soffset = fibh.eoffset = (nf_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
 127         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
 128                 fibh.sbh = fibh.ebh = NULL;
 129         else if (inode_bmap(dir, nf_pos >> (dir->i_sb->s_blocksize_bits - 2),
 130                 &bloc, &extoffset, &eloc, &elen, &offset, &bh) == (EXT_RECORDED_ALLOCATED >> 30))
 131         {
 132                 offset >>= dir->i_sb->s_blocksize_bits;
 133                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
 134                 if ((++offset << dir->i_sb->s_blocksize_bits) < elen)
 135                 {
 136                         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_SHORT)
 137                                 extoffset -= sizeof(short_ad);
 138                         else if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_LONG)
 139                                 extoffset -= sizeof(long_ad);
 140                 }
 141                 else
 142                         offset = 0;
 143
 144                 if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block)))
 145                 {
 146                         udf_release_data(bh);
 147                         return -EIO;
 148                 }
 149
 150                 if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9))-1)))
 151                 {
 152                         i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
 153                         if (i+offset > (elen >> dir->i_sb->s_blocksize_bits))
 154                                 i = (elen >> dir->i_sb->s_blocksize_bits)-offset;
 155                         for (num=0; i>0; i--)
 156                         {
 157                                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset+i);
 158                                 tmp = udf_tgetblk(dir->i_sb, block);
 159                                 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
 160                                         bha[num++] = tmp;
 161                                 else
 162                                         brelse(tmp);
 163                         }
 164                         if (num)
 165                         {
 166                                 ll_rw_block(READA, num, bha);
 167                                 for (i=0; i<num; i++)
 168                                         brelse(bha[i]);
 169                         }
 170                 }
 171         }
 172         else
 173         {
 174                 udf_release_data(bh);
 175                 return -ENOENT;
 176         }
 177
 178         while ( nf_pos < size )
 179         {
 180                 filp->f_pos = nf_pos + 1;
 181
 182                 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &bloc, &extoffset, &eloc, &elen, &offset, &bh);
 183
 184                 if (!fi)
 185                 {
 186                         if (fibh.sbh != fibh.ebh)
 187                                 udf_release_data(fibh.ebh);
 188                         udf_release_data(fibh.sbh);
 189                         udf_release_data(bh);
 190                         return 0;
 191                 }
 192
 193                 liu = le16_to_cpu(cfi.lengthOfImpUse);
 194                 lfi = cfi.lengthFileIdent;
 195
 196                 if (fibh.sbh == fibh.ebh)
 197                         nameptr = fi->fileIdent + liu;
 198                 else
 199                 {
 200                         int poffset;    /* Unpaded ending offset */
 201
 202                         poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
 203
 204                         if (poffset >= lfi)
 205                                 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 206                         else
 207                         {
 208                                 nameptr = fname;
 209                                 memcpy(nameptr, fi->fileIdent + liu, lfi - poffset);
 210                                 memcpy(nameptr + lfi - poffset, fibh.ebh->b_data, poffset);
 211                         }
 212                 }
 213
 214                 if ( (cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0 )
 215                 {
 216                         if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE) )
 217                                 continue;
 218                 }
 219
 220                 if ( (cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0 )
 221                 {
 222                         if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE) )
 223                                 continue;
 224                 }
 225
 226                 if ( cfi.fileCharacteristics & FID_FILE_CHAR_PARENT )
 227                 {
 228                         iblock = parent_ino(filp->f_dentry);
 229                         flen = 2;
 230                         memcpy(fname, "..", flen);
 231                         dt_type = DT_DIR;
 232                 }
 233                 else
 234                 {
 235                         kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
 236
 237                         iblock = udf_get_lb_pblock(dir->i_sb, tloc, 0);
 238                         flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
 239                         dt_type = DT_UNKNOWN;
 240                 }
 241
 242                 if (flen)
 243                 {
 244                         if (filldir(dirent, fname, flen, filp->f_pos, iblock, dt_type) < 0)
 245                         {
 246                                 if (fibh.sbh != fibh.ebh)
 247                                         udf_release_data(fibh.ebh);
 248                                 udf_release_data(fibh.sbh);
 249                                 udf_release_data(bh);
 250                                 return 0;
 251                         }
 252                 }
 253         } /* end while */
 254
 255         filp->f_pos = nf_pos + 1;
 256
 257         if (fibh.sbh != fibh.ebh)
 258                 udf_release_data(fibh.ebh);
 259         udf_release_data(fibh.sbh);
 260         udf_release_data(bh);
 261
 262         return 0;
 263 }