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