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 const 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_path.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 *tmp, *bha[16];
 115         kernel_lb_addr eloc;
 116         uint32_t elen;
 117         sector_t offset;
 118         int i, num;
 119         unsigned int dt_type;
 120         struct extent_position epos = { NULL, 0, {0, 0}};
 121
 122         if (nf_pos >= size)
 123                 return 0;
 124
 125         if (nf_pos == 0)
 126                 nf_pos = (udf_ext0_offset(dir) >> 2);
 127
 128         fibh.soffset = fibh.eoffset = (nf_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
 129         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
 130                 fibh.sbh = fibh.ebh = NULL;
 131         else if (inode_bmap(dir, nf_pos >> (dir->i_sb->s_blocksize_bits - 2),
 132                 &epos, &eloc, &elen, &offset) == (EXT_RECORDED_ALLOCATED >> 30))
 133         {
 134                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
 135                 if ((++offset << dir->i_sb->s_blocksize_bits) < elen)
 136                 {
 137                         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_SHORT)
 138                                 epos.offset -= sizeof(short_ad);
 139                         else if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_LONG)
 140                                 epos.offset -= sizeof(long_ad);
 141                 }
 142                 else
 143                         offset = 0;
 144
 145                 if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block)))
 146                 {
 147                         brelse(epos.bh);
 148                         return -EIO;
 149                 }
 150
 151                 if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9))-1)))
 152                 {
 153                         i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
 154                         if (i+offset > (elen >> dir->i_sb->s_blocksize_bits))
 155                                 i = (elen >> dir->i_sb->s_blocksize_bits)-offset;
 156                         for (num=0; i>0; i--)
 157                         {
 158                                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset+i);
 159                                 tmp = udf_tgetblk(dir->i_sb, block);
 160                                 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
 161                                         bha[num++] = tmp;
 162                                 else
 163                                         brelse(tmp);
 164                         }
 165                         if (num)
 166                         {
 167                                 ll_rw_block(READA, num, bha);
 168                                 for (i=0; i<num; i++)
 169                                         brelse(bha[i]);
 170                         }
 171                 }
 172         }
 173         else
 174         {
 175                 brelse(epos.bh);
 176                 return -ENOENT;
 177         }
 178
 179         while ( nf_pos < size )
 180         {
 181                 filp->f_pos = nf_pos + 1;
 182
 183                 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc, &elen, &offset);
 184
 185                 if (!fi)
 186                 {
 187                         if (fibh.sbh != fibh.ebh)
 188                                 brelse(fibh.ebh);
 189                         brelse(fibh.sbh);
 190                         brelse(epos.bh);
 191                         return 0;
 192                 }
 193
 194                 liu = le16_to_cpu(cfi.lengthOfImpUse);
 195                 lfi = cfi.lengthFileIdent;
 196
 197                 if (fibh.sbh == fibh.ebh)
 198                         nameptr = fi->fileIdent + liu;
 199                 else
 200                 {
 201                         int poffset;    /* Unpaded ending offset */
 202
 203                         poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
 204
 205                         if (poffset >= lfi)
 206                                 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 207                         else
 208                         {
 209                                 nameptr = fname;
 210                                 memcpy(nameptr, fi->fileIdent + liu, lfi - poffset);
 211                                 memcpy(nameptr + lfi - poffset, fibh.ebh->b_data, poffset);
 212                         }
 213                 }
 214
 215                 if ( (cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0 )
 216                 {
 217                         if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE) )
 218                                 continue;
 219                 }
 220
 221                 if ( (cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0 )
 222                 {
 223                         if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE) )
 224                                 continue;
 225                 }
 226
 227                 if ( cfi.fileCharacteristics & FID_FILE_CHAR_PARENT )
 228                 {
 229                         iblock = parent_ino(filp->f_path.dentry);
 230                         flen = 2;
 231                         memcpy(fname, "..", flen);
 232                         dt_type = DT_DIR;
 233                 }
 234                 else
 235                 {
 236                         kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
 237
 238                         iblock = udf_get_lb_pblock(dir->i_sb, tloc, 0);
 239                         flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
 240                         dt_type = DT_UNKNOWN;
 241                 }
 242
 243                 if (flen)
 244                 {
 245                         if (filldir(dirent, fname, flen, filp->f_pos, iblock, dt_type) < 0)
 246                         {
 247                                 if (fibh.sbh != fibh.ebh)
 248                                         brelse(fibh.ebh);
 249                                 brelse(fibh.sbh);
 250                                 brelse(epos.bh);
 251                                 return 0;
 252                         }
 253                 }
 254         } /* end while */
 255
 256         filp->f_pos = nf_pos + 1;
 257
 258         if (fibh.sbh != fibh.ebh)
 259                 brelse(fibh.ebh);
 260         brelse(fibh.sbh);
 261         brelse(epos.bh);
 262
 263         return 0;
 264 }