fs/udf/directory.c

   1 /*
   2  * directory.c
   3  *
   4  * PURPOSE
   5  *      Directory related functions
   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
  14 #include "udfdecl.h"
  15 #include "udf_i.h"
  16
  17 #include <linux/fs.h>
  18 #include <linux/string.h>
  19 #include <linux/bio.h>
  20
  21 struct fileIdentDesc *udf_fileident_read(struct inode *dir, loff_t *nf_pos,
  22                                          struct udf_fileident_bh *fibh,
  23                                          struct fileIdentDesc *cfi,
  24                                          struct extent_position *epos,
  25                                          struct kernel_lb_addr *eloc, uint32_t *elen,
  26                                          sector_t *offset)
  27 {
  28         struct fileIdentDesc *fi;
  29         int i, num;
  30         udf_pblk_t block;
  31         struct buffer_head *tmp, *bha[16];
  32         struct udf_inode_info *iinfo = UDF_I(dir);
  33
  34         fibh->soffset = fibh->eoffset;
  35
  36         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
  37                 fi = udf_get_fileident(iinfo->i_data -
  38                                        (iinfo->i_efe ?
  39                                         sizeof(struct extendedFileEntry) :
  40                                         sizeof(struct fileEntry)),
  41                                        dir->i_sb->s_blocksize,
  42                                        &(fibh->eoffset));
  43                 if (!fi)
  44                         return NULL;
  45
  46                 *nf_pos += fibh->eoffset - fibh->soffset;
  47
  48                 memcpy((uint8_t *)cfi, (uint8_t *)fi,
  49                        sizeof(struct fileIdentDesc));
  50
  51                 return fi;
  52         }
  53
  54         if (fibh->eoffset == dir->i_sb->s_blocksize) {
  55                 uint32_t lextoffset = epos->offset;
  56                 unsigned char blocksize_bits = dir->i_sb->s_blocksize_bits;
  57
  58                 if (udf_next_aext(dir, epos, eloc, elen, 1) !=
  59                     (EXT_RECORDED_ALLOCATED >> 30))
  60                         return NULL;
  61
  62                 block = udf_get_lb_pblock(dir->i_sb, eloc, *offset);
  63
  64                 (*offset)++;
  65
  66                 if ((*offset << blocksize_bits) >= *elen)
  67                         *offset = 0;
  68                 else
  69                         epos->offset = lextoffset;
  70
  71                 brelse(fibh->sbh);
  72                 fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block);
  73                 if (!fibh->sbh)
  74                         return NULL;
  75                 fibh->soffset = fibh->eoffset = 0;
  76
  77                 if (!(*offset & ((16 >> (blocksize_bits - 9)) - 1))) {
  78                         i = 16 >> (blocksize_bits - 9);
  79                         if (i + *offset > (*elen >> blocksize_bits))
  80                                 i = (*elen >> blocksize_bits)-*offset;
  81                         for (num = 0; i > 0; i--) {
  82                                 block = udf_get_lb_pblock(dir->i_sb, eloc,
  83                                                           *offset + i);
  84                                 tmp = udf_tgetblk(dir->i_sb, block);
  85                                 if (tmp && !buffer_uptodate(tmp) &&
  86                                                 !buffer_locked(tmp))
  87                                         bha[num++] = tmp;
  88                                 else
  89                                         brelse(tmp);
  90                         }
  91                         if (num) {
  92                                 bh_readahead_batch(num, bha, REQ_RAHEAD);
  93                                 for (i = 0; i < num; i++)
  94                                         brelse(bha[i]);
  95                         }
  96                 }
  97         } else if (fibh->sbh != fibh->ebh) {
  98                 brelse(fibh->sbh);
  99                 fibh->sbh = fibh->ebh;
 100         }
 101
 102         fi = udf_get_fileident(fibh->sbh->b_data, dir->i_sb->s_blocksize,
 103                                &(fibh->eoffset));
 104
 105         if (!fi)
 106                 return NULL;
 107
 108         *nf_pos += fibh->eoffset - fibh->soffset;
 109
 110         if (fibh->eoffset <= dir->i_sb->s_blocksize) {
 111                 memcpy((uint8_t *)cfi, (uint8_t *)fi,
 112                        sizeof(struct fileIdentDesc));
 113         } else if (fibh->eoffset > dir->i_sb->s_blocksize) {
 114                 uint32_t lextoffset = epos->offset;
 115
 116                 if (udf_next_aext(dir, epos, eloc, elen, 1) !=
 117                     (EXT_RECORDED_ALLOCATED >> 30))
 118                         return NULL;
 119
 120                 block = udf_get_lb_pblock(dir->i_sb, eloc, *offset);
 121
 122                 (*offset)++;
 123
 124                 if ((*offset << dir->i_sb->s_blocksize_bits) >= *elen)
 125                         *offset = 0;
 126                 else
 127                         epos->offset = lextoffset;
 128
 129                 fibh->soffset -= dir->i_sb->s_blocksize;
 130                 fibh->eoffset -= dir->i_sb->s_blocksize;
 131
 132                 fibh->ebh = udf_tread(dir->i_sb, block);
 133                 if (!fibh->ebh)
 134                         return NULL;
 135
 136                 if (sizeof(struct fileIdentDesc) > -fibh->soffset) {
 137                         int fi_len;
 138
 139                         memcpy((uint8_t *)cfi, (uint8_t *)fi, -fibh->soffset);
 140                         memcpy((uint8_t *)cfi - fibh->soffset,
 141                                fibh->ebh->b_data,
 142                                sizeof(struct fileIdentDesc) + fibh->soffset);
 143
 144                         fi_len = udf_dir_entry_len(cfi);
 145                         *nf_pos += fi_len - (fibh->eoffset - fibh->soffset);
 146                         fibh->eoffset = fibh->soffset + fi_len;
 147                 } else {
 148                         memcpy((uint8_t *)cfi, (uint8_t *)fi,
 149                                sizeof(struct fileIdentDesc));
 150                 }
 151         }
 152         /* Got last entry outside of dir size - fs is corrupted! */
 153         if (*nf_pos > dir->i_size)
 154                 return NULL;
 155         return fi;
 156 }
 157
 158 struct fileIdentDesc *udf_get_fileident(void *buffer, int bufsize, int *offset)
 159 {
 160         struct fileIdentDesc *fi;
 161         int lengthThisIdent;
 162         uint8_t *ptr;
 163         int padlen;
 164
 165         if ((!buffer) || (!offset)) {
 166                 udf_debug("invalidparms, buffer=%p, offset=%p\n",
 167                           buffer, offset);
 168                 return NULL;
 169         }
 170
 171         ptr = buffer;
 172
 173         if ((*offset > 0) && (*offset < bufsize))
 174                 ptr += *offset;
 175         fi = (struct fileIdentDesc *)ptr;
 176         if (fi->descTag.tagIdent != cpu_to_le16(TAG_IDENT_FID)) {
 177                 udf_debug("0x%x != TAG_IDENT_FID\n",
 178                           le16_to_cpu(fi->descTag.tagIdent));
 179                 udf_debug("offset: %d sizeof: %lu bufsize: %d\n",
 180                           *offset, (unsigned long)sizeof(struct fileIdentDesc),
 181                           bufsize);
 182                 return NULL;
 183         }
 184         if ((*offset + sizeof(struct fileIdentDesc)) > bufsize)
 185                 lengthThisIdent = sizeof(struct fileIdentDesc);
 186         else
 187                 lengthThisIdent = sizeof(struct fileIdentDesc) +
 188                         fi->lengthFileIdent + le16_to_cpu(fi->lengthOfImpUse);
 189
 190         /* we need to figure padding, too! */
 191         padlen = lengthThisIdent % UDF_NAME_PAD;
 192         if (padlen)
 193                 lengthThisIdent += (UDF_NAME_PAD - padlen);
 194         *offset = *offset + lengthThisIdent;
 195
 196         return fi;
 197 }
 198
 199 struct short_ad *udf_get_fileshortad(uint8_t *ptr, int maxoffset, uint32_t *offset,
 200                               int inc)
 201 {
 202         struct short_ad *sa;
 203
 204         if ((!ptr) || (!offset)) {
 205                 pr_err("%s: invalidparms\n", __func__);
 206                 return NULL;
 207         }
 208
 209         if ((*offset + sizeof(struct short_ad)) > maxoffset)
 210                 return NULL;
 211         else {
 212                 sa = (struct short_ad *)ptr;
 213                 if (sa->extLength == 0)
 214                         return NULL;
 215         }
 216
 217         if (inc)
 218                 *offset += sizeof(struct short_ad);
 219         return sa;
 220 }
 221
 222 struct long_ad *udf_get_filelongad(uint8_t *ptr, int maxoffset, uint32_t *offset, int inc)
 223 {
 224         struct long_ad *la;
 225
 226         if ((!ptr) || (!offset)) {
 227                 pr_err("%s: invalidparms\n", __func__);
 228                 return NULL;
 229         }
 230
 231         if ((*offset + sizeof(struct long_ad)) > maxoffset)
 232                 return NULL;
 233         else {
 234                 la = (struct long_ad *)ptr;
 235                 if (la->extLength == 0)
 236                         return NULL;
 237         }
 238
 239         if (inc)
 240                 *offset += sizeof(struct long_ad);
 241         return la;
 242 }