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 = { .sbh = NULL, .ebh = NULL};
  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         unsigned char *fname = NULL;
  49         unsigned 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         struct kernel_lb_addr eloc;
  55         uint32_t elen;
  56         sector_t offset;
  57         int i, num, ret = 0;
  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                 goto out;
  64
  65         fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
  66         if (!fname) {
  67                 ret = -ENOMEM;
  68                 goto out;
  69         }
  70
  71         if (nf_pos == 0)
  72                 nf_pos = udf_ext0_offset(dir);
  73
  74         fibh.soffset = fibh.eoffset = nf_pos & (dir->i_sb->s_blocksize - 1);
  75         iinfo = UDF_I(dir);
  76         if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
  77                 if (inode_bmap(dir, nf_pos >> dir->i_sb->s_blocksize_bits,
  78                     &epos, &eloc, &elen, &offset)
  79                     != (EXT_RECORDED_ALLOCATED >> 30)) {
  80                         ret = -ENOENT;
  81                         goto out;
  82                 }
  83                 block = udf_get_lb_pblock(dir->i_sb, &eloc, offset);
  84                 if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
  85                         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  86                                 epos.offset -= sizeof(struct short_ad);
  87                         else if (iinfo->i_alloc_type ==
  88                                         ICBTAG_FLAG_AD_LONG)
  89                                 epos.offset -= sizeof(struct long_ad);
  90                 } else {
  91                         offset = 0;
  92                 }
  93
  94                 if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block))) {
  95                         ret = -EIO;
  96                         goto out;
  97                 }
  98
  99                 if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1))) {
 100                         i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
 101                         if (i + offset > (elen >> dir->i_sb->s_blocksize_bits))
 102                                 i = (elen >> dir->i_sb->s_blocksize_bits) - offset;
 103                         for (num = 0; i > 0; i--) {
 104                                 block = udf_get_lb_pblock(dir->i_sb, &eloc, offset + i);
 105                                 tmp = udf_tgetblk(dir->i_sb, block);
 106                                 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
 107                                         bha[num++] = tmp;
 108                                 else
 109                                         brelse(tmp);
 110                         }
 111                         if (num) {
 112                                 ll_rw_block(READA, num, bha);
 113                                 for (i = 0; i < num; i++)
 114                                         brelse(bha[i]);
 115                         }
 116                 }
 117         }
 118
 119         while (nf_pos < size) {
 120                 filp->f_pos = (nf_pos >> 2) + 1;
 121
 122                 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
 123                                         &elen, &offset);
 124                 if (!fi)
 125                         goto out;
 126
 127                 liu = le16_to_cpu(cfi.lengthOfImpUse);
 128                 lfi = cfi.lengthFileIdent;
 129
 130                 if (fibh.sbh == fibh.ebh) {
 131                         nameptr = fi->fileIdent + liu;
 132                 } else {
 133                         int poffset;    /* Unpaded ending offset */
 134
 135                         poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
 136
 137                         if (poffset >= lfi) {
 138                                 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 139                         } else {
 140                                 nameptr = fname;
 141                                 memcpy(nameptr, fi->fileIdent + liu,
 142                                        lfi - poffset);
 143                                 memcpy(nameptr + lfi - poffset,
 144                                        fibh.ebh->b_data, poffset);
 145                         }
 146                 }
 147
 148                 if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
 149                         if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE))
 150                                 continue;
 151                 }
 152
 153                 if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
 154                         if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE))
 155                                 continue;
 156                 }
 157
 158                 if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
 159                         iblock = parent_ino(filp->f_path.dentry);
 160                         flen = 2;
 161                         memcpy(fname, "..", flen);
 162                         dt_type = DT_DIR;
 163                 } else {
 164                         struct kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
 165
 166                         iblock = udf_get_lb_pblock(dir->i_sb, &tloc, 0);
 167                         flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
 168                         dt_type = DT_UNKNOWN;
 169                 }
 170
 171                 if (flen && filldir(dirent, fname, flen, filp->f_pos,
 172                                     iblock, dt_type) < 0)
 173                         goto out;
 174         } /* end while */
 175
 176         filp->f_pos = (nf_pos >> 2) + 1;
 177
 178 out:
 179         if (fibh.sbh != fibh.ebh)
 180                 brelse(fibh.ebh);
 181         brelse(fibh.sbh);
 182         brelse(epos.bh);
 183         kfree(fname);
 184
 185         return ret;
 186 }
 187
 188 static int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
 189 {
 190         struct inode *dir = filp->f_path.dentry->d_inode;
 191         int result;
 192
 193         lock_kernel();
 194
 195         if (filp->f_pos == 0) {
 196                 if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) < 0) {
 197                         unlock_kernel();
 198                         return 0;
 199                 }
 200                 filp->f_pos++;
 201         }
 202
 203         result = do_udf_readdir(dir, filp, filldir, dirent);
 204         unlock_kernel();
 205         return result;
 206 }
 207
 208 /* readdir and lookup functions */
 209 const struct file_operations udf_dir_operations = {
 210         .llseek                 = generic_file_llseek,
 211         .read                   = generic_read_dir,
 212         .readdir                = udf_readdir,
 213         .unlocked_ioctl         = udf_ioctl,
 214         .fsync                  = generic_file_fsync,
 215 };