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) < 0) {
  87                         unlock_kernel();
  88                         return 0;
  89                 }
  90                 filp->f_pos++;
  91         }
  92
  93         result = do_udf_readdir(dir, filp, filldir, dirent);
  94         unlock_kernel();
  95         return result;
  96 }
  97
  98 static int
  99 do_udf_readdir(struct inode *dir, struct file *filp, filldir_t filldir,
 100                void *dirent)
 101 {
 102         struct udf_fileident_bh fibh;
 103         struct fileIdentDesc *fi = NULL;
 104         struct fileIdentDesc cfi;
 105         int block, iblock;
 106         loff_t nf_pos = filp->f_pos - 1;
 107         int flen;
 108         char fname[UDF_NAME_LEN];
 109         char *nameptr;
 110         uint16_t liu;
 111         uint8_t lfi;
 112         loff_t size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
 113         struct buffer_head *tmp, *bha[16];
 114         kernel_lb_addr eloc;
 115         uint32_t elen;
 116         sector_t offset;
 117         int i, num;
 118         unsigned int dt_type;
 119         struct extent_position epos = { NULL, 0, {0, 0} };
 120
 121         if (nf_pos >= size)
 122                 return 0;
 123
 124         if (nf_pos == 0)
 125                 nf_pos = (udf_ext0_offset(dir) >> 2);
 126
 127         fibh.soffset = fibh.eoffset = (nf_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
 128         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB) {
 129                 fibh.sbh = fibh.ebh = NULL;
 130         } else if (inode_bmap(dir, nf_pos >> (dir->i_sb->s_blocksize_bits - 2),
 131                               &epos, &eloc, &elen, &offset) == (EXT_RECORDED_ALLOCATED >> 30)) {
 132                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
 133                 if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
 134                         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_SHORT)
 135                                 epos.offset -= sizeof(short_ad);
 136                         else if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_LONG)
 137                                 epos.offset -= sizeof(long_ad);
 138                 } else {
 139                         offset = 0;
 140                 }
 141
 142                 if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block))) {
 143                         brelse(epos.bh);
 144                         return -EIO;
 145                 }
 146
 147                 if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1))) {
 148                         i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
 149                         if (i + offset > (elen >> dir->i_sb->s_blocksize_bits))
 150                                 i = (elen >> dir->i_sb->s_blocksize_bits) - offset;
 151                         for (num = 0; i > 0; i--) {
 152                                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset + i);
 153                                 tmp = udf_tgetblk(dir->i_sb, block);
 154                                 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
 155                                         bha[num++] = tmp;
 156                                 else
 157                                         brelse(tmp);
 158                         }
 159                         if (num) {
 160                                 ll_rw_block(READA, num, bha);
 161                                 for (i = 0; i < num; i++)
 162                                         brelse(bha[i]);
 163                         }
 164                 }
 165         } else {
 166                 brelse(epos.bh);
 167                 return -ENOENT;
 168         }
 169
 170         while (nf_pos < size) {
 171                 filp->f_pos = nf_pos + 1;
 172
 173                 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
 174                                         &elen, &offset);
 175                 if (!fi) {
 176                         if (fibh.sbh != fibh.ebh)
 177                                 brelse(fibh.ebh);
 178                         brelse(fibh.sbh);
 179                         brelse(epos.bh);
 180                         return 0;
 181                 }
 182
 183                 liu = le16_to_cpu(cfi.lengthOfImpUse);
 184                 lfi = cfi.lengthFileIdent;
 185
 186                 if (fibh.sbh == fibh.ebh) {
 187                         nameptr = fi->fileIdent + liu;
 188                 } else {
 189                         int poffset;    /* Unpaded ending offset */
 190
 191                         poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
 192
 193                         if (poffset >= lfi) {
 194                                 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 195                         } else {
 196                                 nameptr = fname;
 197                                 memcpy(nameptr, fi->fileIdent + liu,
 198                                        lfi - poffset);
 199                                 memcpy(nameptr + lfi - poffset,
 200                                        fibh.ebh->b_data, poffset);
 201                         }
 202                 }
 203
 204                 if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
 205                         if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE))
 206                                 continue;
 207                 }
 208
 209                 if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
 210                         if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE))
 211                                 continue;
 212                 }
 213
 214                 if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
 215                         iblock = parent_ino(filp->f_path.dentry);
 216                         flen = 2;
 217                         memcpy(fname, "..", flen);
 218                         dt_type = DT_DIR;
 219                 } else {
 220                         kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
 221
 222                         iblock = udf_get_lb_pblock(dir->i_sb, tloc, 0);
 223                         flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
 224                         dt_type = DT_UNKNOWN;
 225                 }
 226
 227                 if (flen) {
 228                         if (filldir(dirent, fname, flen, filp->f_pos, iblock, dt_type) < 0) {
 229                                 if (fibh.sbh != fibh.ebh)
 230                                         brelse(fibh.ebh);
 231                                 brelse(fibh.sbh);
 232                                 brelse(epos.bh);
 233                                 return 0;
 234                         }
 235                 }
 236         } /* end while */
 237
 238         filp->f_pos = nf_pos + 1;
 239
 240         if (fibh.sbh != fibh.ebh)
 241                 brelse(fibh.ebh);
 242         brelse(fibh.sbh);
 243         brelse(epos.bh);
 244
 245         return 0;
 246 }