fs/udf/dir.c

   1 /*
   2  * dir.c
   3  *
   4  * PURPOSE
   5  *  Directory handling routines for the OSTA-UDF(tm) filesystem.
   6  *
   7  * CONTACTS
   8  *      E-mail regarding any portion of the Linux UDF file system should be
   9  *      directed to the development team mailing list (run by majordomo):
  10  *              linux_udf@hpesjro.fc.hp.com
  11  *
  12  * COPYRIGHT
  13  *      This file is distributed under the terms of the GNU General Public
  14  *      License (GPL). Copies of the GPL can be obtained from:
  15  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  16  *      Each contributing author retains all rights to their own work.
  17  *
  18  *  (C) 1998-2004 Ben Fennema
  19  *
  20  * HISTORY
  21  *
  22  *  10/05/98 dgb  Split directory operations into its own file
  23  *                Implemented directory reads via do_udf_readdir
  24  *  10/06/98      Made directory operations work!
  25  *  11/17/98      Rewrote directory to support ICBTAG_FLAG_AD_LONG
  26  *  11/25/98 blf  Rewrote directory handling (readdir+lookup) to support reading
  27  *                across blocks.
  28  *  12/12/98      Split out the lookup code to namei.c. bulk of directory
  29  *                code now in directory.c:udf_fileident_read.
  30  */
  31
  32 #include "udfdecl.h"
  33
  34 #include <linux/string.h>
  35 #include <linux/errno.h>
  36 #include <linux/mm.h>
  37 #include <linux/slab.h>
  38 #include <linux/smp_lock.h>
  39 #include <linux/buffer_head.h>
  40
  41 #include "udf_i.h"
  42 #include "udf_sb.h"
  43
  44 /* Prototypes for file operations */
  45 static int udf_readdir(struct file *, void *, filldir_t);
  46 static int do_udf_readdir(struct inode *, struct file *, filldir_t, void *);
  47
  48 /* readdir and lookup functions */
  49
  50 struct file_operations udf_dir_operations = {
  51         .read                   = generic_read_dir,
  52         .readdir                = udf_readdir,
  53         .ioctl                  = udf_ioctl,
  54         .fsync                  = udf_fsync_file,
  55 };
  56
  57 /*
  58  * udf_readdir
  59  *
  60  * PURPOSE
  61  *      Read a directory entry.
  62  *
  63  * DESCRIPTION
  64  *      Optional - sys_getdents() will return -ENOTDIR if this routine is not
  65  *      available.
  66  *
  67  *      Refer to sys_getdents() in fs/readdir.c
  68  *      sys_getdents() -> .
  69  *
  70  * PRE-CONDITIONS
  71  *      filp                    Pointer to directory file.
  72  *      buf                     Pointer to directory entry buffer.
  73  *      filldir                 Pointer to filldir function.
  74  *
  75  * POST-CONDITIONS
  76  *      <return>                >=0 on success.
  77  *
  78  * HISTORY
  79  *      July 1, 1997 - Andrew E. Mileski
  80  *      Written, tested, and released.
  81  */
  82
  83 int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
  84 {
  85         struct inode *dir = filp->f_dentry->d_inode;
  86         int result;
  87
  88         lock_kernel();
  89
  90         if ( filp->f_pos == 0 )
  91         {
  92                 if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) < 0)
  93                 {
  94                         unlock_kernel();
  95                         return 0;
  96                 }
  97                 filp->f_pos ++;
  98         }
  99
 100         result = do_udf_readdir(dir, filp, filldir, dirent);
 101         unlock_kernel();
 102         return result;
 103 }
 104
 105 static int
 106 do_udf_readdir(struct inode * dir, struct file *filp, filldir_t filldir, void *dirent)
 107 {
 108         struct udf_fileident_bh fibh;
 109         struct fileIdentDesc *fi=NULL;
 110         struct fileIdentDesc cfi;
 111         int block, iblock;
 112         loff_t nf_pos = filp->f_pos - 1;
 113         int flen;
 114         char fname[UDF_NAME_LEN];
 115         char *nameptr;
 116         uint16_t liu;
 117         uint8_t lfi;
 118         loff_t size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
 119         struct buffer_head * bh = NULL, * tmp, * bha[16];
 120         kernel_lb_addr bloc, eloc;
 121         uint32_t extoffset, elen, offset;
 122         int i, num;
 123         unsigned int dt_type;
 124
 125         if (nf_pos >= size)
 126                 return 0;
 127
 128         if (nf_pos == 0)
 129                 nf_pos = (udf_ext0_offset(dir) >> 2);
 130
 131         fibh.soffset = fibh.eoffset = (nf_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
 132         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
 133                 fibh.sbh = fibh.ebh = NULL;
 134         else if (inode_bmap(dir, nf_pos >> (dir->i_sb->s_blocksize_bits - 2),
 135                 &bloc, &extoffset, &eloc, &elen, &offset, &bh) == (EXT_RECORDED_ALLOCATED >> 30))
 136         {
 137                 offset >>= dir->i_sb->s_blocksize_bits;
 138                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
 139                 if ((++offset << dir->i_sb->s_blocksize_bits) < elen)
 140                 {
 141                         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_SHORT)
 142                                 extoffset -= sizeof(short_ad);
 143                         else if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_LONG)
 144                                 extoffset -= sizeof(long_ad);
 145                 }
 146                 else
 147                         offset = 0;
 148
 149                 if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block)))
 150                 {
 151                         udf_release_data(bh);
 152                         return -EIO;
 153                 }
 154
 155                 if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9))-1)))
 156                 {
 157                         i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
 158                         if (i+offset > (elen >> dir->i_sb->s_blocksize_bits))
 159                                 i = (elen >> dir->i_sb->s_blocksize_bits)-offset;
 160                         for (num=0; i>0; i--)
 161                         {
 162                                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset+i);
 163                                 tmp = udf_tgetblk(dir->i_sb, block);
 164                                 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
 165                                         bha[num++] = tmp;
 166                                 else
 167                                         brelse(tmp);
 168                         }
 169                         if (num)
 170                         {
 171                                 ll_rw_block(READA, num, bha);
 172                                 for (i=0; i<num; i++)
 173                                         brelse(bha[i]);
 174                         }
 175                 }
 176         }
 177         else
 178         {
 179                 udf_release_data(bh);
 180                 return -ENOENT;
 181         }
 182
 183         while ( nf_pos < size )
 184         {
 185                 filp->f_pos = nf_pos + 1;
 186
 187                 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &bloc, &extoffset, &eloc, &elen, &offset, &bh);
 188
 189                 if (!fi)
 190                 {
 191                         if (fibh.sbh != fibh.ebh)
 192                                 udf_release_data(fibh.ebh);
 193                         udf_release_data(fibh.sbh);
 194                         udf_release_data(bh);
 195                         return 0;
 196                 }
 197
 198                 liu = le16_to_cpu(cfi.lengthOfImpUse);
 199                 lfi = cfi.lengthFileIdent;
 200
 201                 if (fibh.sbh == fibh.ebh)
 202                         nameptr = fi->fileIdent + liu;
 203                 else
 204                 {
 205                         int poffset;    /* Unpaded ending offset */
 206
 207                         poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
 208
 209                         if (poffset >= lfi)
 210                                 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 211                         else
 212                         {
 213                                 nameptr = fname;
 214                                 memcpy(nameptr, fi->fileIdent + liu, lfi - poffset);
 215                                 memcpy(nameptr + lfi - poffset, fibh.ebh->b_data, poffset);
 216                         }
 217                 }
 218
 219                 if ( (cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0 )
 220                 {
 221                         if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE) )
 222                                 continue;
 223                 }
 224
 225                 if ( (cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0 )
 226                 {
 227                         if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE) )
 228                                 continue;
 229                 }
 230
 231                 if ( cfi.fileCharacteristics & FID_FILE_CHAR_PARENT )
 232                 {
 233                         iblock = parent_ino(filp->f_dentry);
 234                         flen = 2;
 235                         memcpy(fname, "..", flen);
 236                         dt_type = DT_DIR;
 237                 }
 238                 else
 239                 {
 240                         kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
 241
 242                         iblock = udf_get_lb_pblock(dir->i_sb, tloc, 0);
 243                         flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
 244                         dt_type = DT_UNKNOWN;
 245                 }
 246
 247                 if (flen)
 248                 {
 249                         if (filldir(dirent, fname, flen, filp->f_pos, iblock, dt_type) < 0)
 250                         {
 251                                 if (fibh.sbh != fibh.ebh)
 252                                         udf_release_data(fibh.ebh);
 253                                 udf_release_data(fibh.sbh);
 254                                 udf_release_data(bh);
 255                                 return 0;
 256                         }
 257                 }
 258         } /* end while */
 259
 260         filp->f_pos = nf_pos + 1;
 261
 262         if (fibh.sbh != fibh.ebh)
 263                 udf_release_data(fibh.ebh);
 264         udf_release_data(fibh.sbh);
 265         udf_release_data(bh);
 266
 267         return 0;
 268 }