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   1 /*
   2  * truncate.c
   3  *
   4  * PURPOSE
   5  *      Truncate 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) 1999-2004 Ben Fennema
  14  *  (C) 1999 Stelias Computing Inc
  15  *
  16  * HISTORY
  17  *
  18  *  02/24/99 blf  Created.
  19  *
  20  */
  21
  22 #include "udfdecl.h"
  23 #include <linux/fs.h>
  24 #include <linux/mm.h>
  25 #include <linux/udf_fs.h>
  26 #include <linux/buffer_head.h>
  27
  28 #include "udf_i.h"
  29 #include "udf_sb.h"
  30
  31 static void extent_trunc(struct inode * inode, struct extent_position *epos,
  32         kernel_lb_addr eloc, int8_t etype, uint32_t elen, uint32_t nelen)
  33 {
  34         kernel_lb_addr neloc = { 0, 0 };
  35         int last_block = (elen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
  36         int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
  37
  38         if (nelen)
  39         {
  40                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
  41                 {
  42                         udf_free_blocks(inode->i_sb, inode, eloc, 0, last_block);
  43                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
  44                 }
  45                 else
  46                         neloc = eloc;
  47                 nelen = (etype << 30) | nelen;
  48         }
  49
  50         if (elen != nelen)
  51         {
  52                 udf_write_aext(inode, epos, neloc, nelen, 0);
  53                 if (last_block - first_block > 0)
  54                 {
  55                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
  56                                 mark_inode_dirty(inode);
  57
  58                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
  59                                 udf_free_blocks(inode->i_sb, inode, eloc, first_block, last_block - first_block);
  60                 }
  61         }
  62 }
  63
  64 void udf_discard_prealloc(struct inode * inode)
  65 {
  66         struct extent_position epos = { NULL, 0, {0, 0}};
  67         kernel_lb_addr eloc;
  68         uint32_t elen, nelen;
  69         uint64_t lbcount = 0;
  70         int8_t etype = -1, netype;
  71         int adsize;
  72
  73         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB ||
  74                 inode->i_size == UDF_I_LENEXTENTS(inode))
  75                 return;
  76
  77         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
  78                 adsize = sizeof(short_ad);
  79         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
  80                 adsize = sizeof(long_ad);
  81         else
  82                 adsize = 0;
  83
  84         epos.block = UDF_I_LOCATION(inode);
  85
  86         /* Find the last extent in the file */
  87         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1)
  88         {
  89                 etype = netype;
  90                 lbcount += elen;
  91                 if (lbcount > inode->i_size && lbcount - inode->i_size < inode->i_sb->s_blocksize)
  92                 {
  93                         nelen = elen - (lbcount - inode->i_size);
  94                         epos.offset -= adsize;
  95                         extent_trunc(inode, &epos, eloc, etype, elen, nelen);
  96                         epos.offset += adsize;
  97                         lbcount = inode->i_size;
  98                 }
  99         }
 100         if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
 101                 epos.offset -= adsize;
 102                 lbcount -= elen;
 103                 extent_trunc(inode, &epos, eloc, etype, elen, 0);
 104                 if (!epos.bh)
 105                 {
 106                         UDF_I_LENALLOC(inode) = epos.offset - udf_file_entry_alloc_offset(inode);
 107                         mark_inode_dirty(inode);
 108                 }
 109                 else
 110                 {
 111                         struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data);
 112                         aed->lengthAllocDescs = cpu_to_le32(epos.offset - sizeof(struct allocExtDesc));
 113                         if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 114                                 udf_update_tag(epos.bh->b_data, epos.offset);
 115                         else
 116                                 udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
 117                         mark_buffer_dirty_inode(epos.bh, inode);
 118                 }
 119         }
 120         UDF_I_LENEXTENTS(inode) = lbcount;
 121
 122         udf_release_data(epos.bh);
 123 }
 124
 125 void udf_truncate_extents(struct inode * inode)
 126 {
 127         struct extent_position epos;
 128         kernel_lb_addr eloc, neloc = { 0, 0 };
 129         uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
 130         int8_t etype;
 131         sector_t first_block = inode->i_size >> inode->i_sb->s_blocksize_bits, offset;
 132         loff_t byte_offset;
 133         int adsize;
 134
 135         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
 136                 adsize = sizeof(short_ad);
 137         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
 138                 adsize = sizeof(long_ad);
 139         else
 140                 BUG();
 141
 142         etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
 143         byte_offset = (offset << inode->i_sb->s_blocksize_bits) + (inode->i_size & (inode->i_sb->s_blocksize-1));
 144         if (etype != -1)
 145         {
 146                 epos.offset -= adsize;
 147                 extent_trunc(inode, &epos, eloc, etype, elen, byte_offset);
 148                 epos.offset += adsize;
 149                 if (byte_offset)
 150                         lenalloc = epos.offset;
 151                 else
 152                         lenalloc = epos.offset - adsize;
 153
 154                 if (!epos.bh)
 155                         lenalloc -= udf_file_entry_alloc_offset(inode);
 156                 else
 157                         lenalloc -= sizeof(struct allocExtDesc);
 158
 159                 while ((etype = udf_current_aext(inode, &epos, &eloc, &elen, 0)) != -1)
 160                 {
 161                         if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30))
 162                         {
 163                                 udf_write_aext(inode, &epos, neloc, nelen, 0);
 164                                 if (indirect_ext_len)
 165                                 {
 166                                         /* We managed to free all extents in the
 167                                          * indirect extent - free it too */
 168                                         if (!epos.bh)
 169                                                 BUG();
 170                                         udf_free_blocks(inode->i_sb, inode, epos.block, 0, indirect_ext_len);
 171                                 }
 172                                 else
 173                                 {
 174                                         if (!epos.bh)
 175                                         {
 176                                                 UDF_I_LENALLOC(inode) = lenalloc;
 177                                                 mark_inode_dirty(inode);
 178                                         }
 179                                         else
 180                                         {
 181                                                 struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data);
 182                                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 183                                                 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 184                                                         udf_update_tag(epos.bh->b_data, lenalloc +
 185                                                                 sizeof(struct allocExtDesc));
 186                                                 else
 187                                                         udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
 188                                                 mark_buffer_dirty_inode(epos.bh, inode);
 189                                         }
 190                                 }
 191                                 brelse(epos.bh);
 192                                 epos.offset = sizeof(struct allocExtDesc);
 193                                 epos.block = eloc;
 194                                 epos.bh = udf_tread(inode->i_sb, udf_get_lb_pblock(inode->i_sb, eloc, 0));
 195                                 if (elen)
 196                                         indirect_ext_len = (elen +
 197                                                 inode->i_sb->s_blocksize - 1) >>
 198                                                 inode->i_sb->s_blocksize_bits;
 199                                 else
 200                                         indirect_ext_len = 1;
 201                         }
 202                         else
 203                         {
 204                                 extent_trunc(inode, &epos, eloc, etype, elen, 0);
 205                                 epos.offset += adsize;
 206                         }
 207                 }
 208
 209                 if (indirect_ext_len)
 210                 {
 211                         if (!epos.bh)
 212                                 BUG();
 213                         udf_free_blocks(inode->i_sb, inode, epos.block, 0, indirect_ext_len);
 214                 }
 215                 else
 216                 {
 217                         if (!epos.bh)
 218                         {
 219                                 UDF_I_LENALLOC(inode) = lenalloc;
 220                                 mark_inode_dirty(inode);
 221                         }
 222                         else
 223                         {
 224                                 struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data);
 225                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 226                                 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 227                                         udf_update_tag(epos.bh->b_data, lenalloc +
 228                                                 sizeof(struct allocExtDesc));
 229                                 else
 230                                         udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
 231                                 mark_buffer_dirty_inode(epos.bh, inode);
 232                         }
 233                 }
 234         }
 235         else if (inode->i_size)
 236         {
 237                 if (byte_offset)
 238                 {
 239                         /*
 240                          *  OK, there is not extent covering inode->i_size and
 241                          *  no extent above inode->i_size => truncate is
 242                          *  extending the file by 'offset'.
 243                          */
 244                         if ((!epos.bh && epos.offset == udf_file_entry_alloc_offset(inode)) ||
 245                             (epos.bh && epos.offset == sizeof(struct allocExtDesc))) {
 246                                 /* File has no extents at all! */
 247                                 memset(&eloc, 0x00, sizeof(kernel_lb_addr));
 248                                 elen = EXT_NOT_RECORDED_NOT_ALLOCATED | byte_offset;
 249                                 udf_add_aext(inode, &epos, eloc, elen, 1);
 250                         }
 251                         else {
 252                                 epos.offset -= adsize;
 253                                 etype = udf_next_aext(inode, &epos, &eloc, &elen, 1);
 254
 255                                 if (etype == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
 256                                 {
 257                                         epos.offset -= adsize;
 258                                         elen = EXT_NOT_RECORDED_NOT_ALLOCATED | (elen + byte_offset);
 259                                         udf_write_aext(inode, &epos, eloc, elen, 0);
 260                                 }
 261                                 else if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
 262                                 {
 263                                         kernel_lb_addr neloc = { 0, 0 };
 264                                         epos.offset -= adsize;
 265                                         nelen = EXT_NOT_RECORDED_NOT_ALLOCATED |
 266                                                 ((elen + byte_offset + inode->i_sb->s_blocksize - 1) &
 267                                                 ~(inode->i_sb->s_blocksize - 1));
 268                                         udf_write_aext(inode, &epos, neloc, nelen, 1);
 269                                         udf_add_aext(inode, &epos, eloc, (etype << 30) | elen, 1);
 270                                 }
 271                                 else
 272                                 {
 273                                         if (elen & (inode->i_sb->s_blocksize - 1))
 274                                         {
 275                                                 epos.offset -= adsize;
 276                                                 elen = EXT_RECORDED_ALLOCATED |
 277                                                         ((elen + inode->i_sb->s_blocksize - 1) &
 278                                                         ~(inode->i_sb->s_blocksize - 1));
 279                                                 udf_write_aext(inode, &epos, eloc, elen, 1);
 280                                         }
 281                                         memset(&eloc, 0x00, sizeof(kernel_lb_addr));
 282                                         elen = EXT_NOT_RECORDED_NOT_ALLOCATED | byte_offset;
 283                                         udf_add_aext(inode, &epos, eloc, elen, 1);
 284                                 }
 285                         }
 286                 }
 287         }
 288         UDF_I_LENEXTENTS(inode) = inode->i_size;
 289
 290         udf_release_data(epos.bh);
 291 }