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                 if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) <
  87                     0) {
  88                         unlock_kernel();
  89                         return 0;
  90                 }
  91                 filp->f_pos++;
  92         }
  93
  94         result = do_udf_readdir(dir, filp, filldir, dirent);
  95         unlock_kernel();
  96         return result;
  97 }
  98
  99 static int
 100 do_udf_readdir(struct inode *dir, struct file *filp, filldir_t filldir,
 101                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 =
 129             (nf_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
 130         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
 131                 fibh.sbh = fibh.ebh = NULL;
 132         else if (inode_bmap(dir, nf_pos >> (dir->i_sb->s_blocksize_bits - 2),
 133                             &epos, &eloc, &elen,
 134                             &offset) == (EXT_RECORDED_ALLOCATED >> 30)) {
 135                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
 136                 if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
 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                 } else
 142                         offset = 0;
 143
 144                 if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block))) {
 145                         brelse(epos.bh);
 146                         return -EIO;
 147                 }
 148
 149                 if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1))) {
 150                         i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
 151                         if (i + offset > (elen >> dir->i_sb->s_blocksize_bits))
 152                                 i = (elen >> dir->i_sb->s_blocksize_bits) -
 153                                     offset;
 154                         for (num = 0; i > 0; i--) {
 155                                 block =
 156                                     udf_get_lb_pblock(dir->i_sb, eloc,
 157                                                       offset + i);
 158                                 tmp = udf_tgetblk(dir->i_sb, block);
 159                                 if (tmp && !buffer_uptodate(tmp)
 160                                     && !buffer_locked(tmp))
 161                                         bha[num++] = tmp;
 162                                 else
 163                                         brelse(tmp);
 164                         }
 165                         if (num) {
 166                                 ll_rw_block(READA, num, bha);
 167                                 for (i = 0; i < num; i++)
 168                                         brelse(bha[i]);
 169                         }
 170                 }
 171         } else {
 172                 brelse(epos.bh);
 173                 return -ENOENT;
 174         }
 175
 176         while (nf_pos < size) {
 177                 filp->f_pos = nf_pos + 1;
 178
 179                 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
 180                                         &elen, &offset);
 181
 182                 if (!fi) {
 183                         if (fibh.sbh != fibh.ebh)
 184                                 brelse(fibh.ebh);
 185                         brelse(fibh.sbh);
 186                         brelse(epos.bh);
 187                         return 0;
 188                 }
 189
 190                 liu = le16_to_cpu(cfi.lengthOfImpUse);
 191                 lfi = cfi.lengthFileIdent;
 192
 193                 if (fibh.sbh == fibh.ebh)
 194                         nameptr = fi->fileIdent + liu;
 195                 else {
 196                         int poffset;    /* Unpaded ending offset */
 197
 198                         poffset =
 199                             fibh.soffset + sizeof(struct fileIdentDesc) + liu +
 200                             lfi;
 201
 202                         if (poffset >= lfi)
 203                                 nameptr =
 204                                     (char *)(fibh.ebh->b_data + poffset - lfi);
 205                         else {
 206                                 nameptr = fname;
 207                                 memcpy(nameptr, fi->fileIdent + liu,
 208                                        lfi - poffset);
 209                                 memcpy(nameptr + lfi - poffset,
 210                                        fibh.ebh->b_data, poffset);
 211                         }
 212                 }
 213
 214                 if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
 215                         if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE))
 216                                 continue;
 217                 }
 218
 219                 if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
 220                         if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE))
 221                                 continue;
 222                 }
 223
 224                 if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
 225                         iblock = parent_ino(filp->f_path.dentry);
 226                         flen = 2;
 227                         memcpy(fname, "..", flen);
 228                         dt_type = DT_DIR;
 229                 } else {
 230                         kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
 231
 232                         iblock = udf_get_lb_pblock(dir->i_sb, tloc, 0);
 233                         flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
 234                         dt_type = DT_UNKNOWN;
 235                 }
 236
 237                 if (flen) {
 238                         if (filldir
 239                             (dirent, fname, flen, filp->f_pos, iblock,
 240                              dt_type) < 0) {
 241                                 if (fibh.sbh != fibh.ebh)
 242                                         brelse(fibh.ebh);
 243                                 brelse(fibh.sbh);
 244                                 brelse(epos.bh);
 245                                 return 0;
 246                         }
 247                 }
 248         }                       /* end while */
 249
 250         filp->f_pos = nf_pos + 1;
 251
 252         if (fibh.sbh != fibh.ebh)
 253                 brelse(fibh.ebh);
 254         brelse(fibh.sbh);
 255         brelse(epos.bh);
 256
 257         return 0;
 258 }