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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,
  33                          uint32_t nelen)
  34 {
  35         kernel_lb_addr neloc = {};
  36         int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
  37                 inode->i_sb->s_blocksize_bits;
  38         int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
  39                 inode->i_sb->s_blocksize_bits;
  40
  41         if (nelen) {
  42                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
  43                         udf_free_blocks(inode->i_sb, inode, eloc, 0,
  44                                         last_block);
  45                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
  46                 } else
  47                         neloc = eloc;
  48                 nelen = (etype << 30) | nelen;
  49         }
  50
  51         if (elen != nelen) {
  52                 udf_write_aext(inode, epos, neloc, nelen, 0);
  53                 if (last_block - first_block > 0) {
  54                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
  55                                 mark_inode_dirty(inode);
  56
  57                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
  58                                 udf_free_blocks(inode->i_sb, inode, eloc,
  59                                                 first_block,
  60                                                 last_block - first_block);
  61                 }
  62         }
  63 }
  64
  65 /*
  66  * Truncate the last extent to match i_size. This function assumes
  67  * that preallocation extent is already truncated.
  68  */
  69 void udf_truncate_tail_extent(struct inode *inode)
  70 {
  71         struct extent_position epos = {};
  72         kernel_lb_addr eloc;
  73         uint32_t elen, nelen;
  74         uint64_t lbcount = 0;
  75         int8_t etype = -1, netype;
  76         int adsize;
  77         struct udf_inode_info *iinfo = UDF_I(inode);
  78
  79         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
  80             inode->i_size == iinfo->i_lenExtents)
  81                 return;
  82         /* Are we going to delete the file anyway? */
  83         if (inode->i_nlink == 0)
  84                 return;
  85
  86         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  87                 adsize = sizeof(short_ad);
  88         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
  89                 adsize = sizeof(long_ad);
  90         else
  91                 BUG();
  92
  93         /* Find the last extent in the file */
  94         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
  95                 etype = netype;
  96                 lbcount += elen;
  97                 if (lbcount > inode->i_size) {
  98                         if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
  99                                 printk(KERN_WARNING
 100                                        "udf_truncate_tail_extent(): Too long "
 101                                        "extent after EOF in inode %u: i_size: "
 102                                        "%Ld lbcount: %Ld extent %u+%u\n",
 103                                        (unsigned)inode->i_ino,
 104                                        (long long)inode->i_size,
 105                                        (long long)lbcount,
 106                                        (unsigned)eloc.logicalBlockNum,
 107                                        (unsigned)elen);
 108                         nelen = elen - (lbcount - inode->i_size);
 109                         epos.offset -= adsize;
 110                         extent_trunc(inode, &epos, eloc, etype, elen, nelen);
 111                         epos.offset += adsize;
 112                         if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
 113                                 printk(KERN_ERR "udf_truncate_tail_extent(): "
 114                                        "Extent after EOF in inode %u.\n",
 115                                        (unsigned)inode->i_ino);
 116                         break;
 117                 }
 118         }
 119         /* This inode entry is in-memory only and thus we don't have to mark
 120          * the inode dirty */
 121         iinfo->i_lenExtents = inode->i_size;
 122         brelse(epos.bh);
 123 }
 124
 125 void udf_discard_prealloc(struct inode *inode)
 126 {
 127         struct extent_position epos = { NULL, 0, {0, 0} };
 128         kernel_lb_addr eloc;
 129         uint32_t elen;
 130         uint64_t lbcount = 0;
 131         int8_t etype = -1, netype;
 132         int adsize;
 133         struct udf_inode_info *iinfo = UDF_I(inode);
 134
 135         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
 136             inode->i_size == iinfo->i_lenExtents)
 137                 return;
 138
 139         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 140                 adsize = sizeof(short_ad);
 141         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 142                 adsize = sizeof(long_ad);
 143         else
 144                 adsize = 0;
 145
 146         epos.block = iinfo->i_location;
 147
 148         /* Find the last extent in the file */
 149         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
 150                 etype = netype;
 151                 lbcount += elen;
 152         }
 153         if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
 154                 epos.offset -= adsize;
 155                 lbcount -= elen;
 156                 extent_trunc(inode, &epos, eloc, etype, elen, 0);
 157                 if (!epos.bh) {
 158                         iinfo->i_lenAlloc =
 159                                 epos.offset -
 160                                 udf_file_entry_alloc_offset(inode);
 161                         mark_inode_dirty(inode);
 162                 } else {
 163                         struct allocExtDesc *aed =
 164                                 (struct allocExtDesc *)(epos.bh->b_data);
 165                         aed->lengthAllocDescs =
 166                                 cpu_to_le32(epos.offset -
 167                                             sizeof(struct allocExtDesc));
 168                         if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) ||
 169                             UDF_SB(inode->i_sb)->s_udfrev >= 0x0201)
 170                                 udf_update_tag(epos.bh->b_data, epos.offset);
 171                         else
 172                                 udf_update_tag(epos.bh->b_data,
 173                                                sizeof(struct allocExtDesc));
 174                         mark_buffer_dirty_inode(epos.bh, inode);
 175                 }
 176         }
 177         /* This inode entry is in-memory only and thus we don't have to mark
 178          * the inode dirty */
 179         iinfo->i_lenExtents = lbcount;
 180         brelse(epos.bh);
 181 }
 182
 183 void udf_truncate_extents(struct inode *inode)
 184 {
 185         struct extent_position epos;
 186         kernel_lb_addr eloc, neloc = {};
 187         uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
 188         int8_t etype;
 189         struct super_block *sb = inode->i_sb;
 190         struct udf_sb_info *sbi = UDF_SB(sb);
 191         sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
 192         loff_t byte_offset;
 193         int adsize;
 194         struct udf_inode_info *iinfo = UDF_I(inode);
 195
 196         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 197                 adsize = sizeof(short_ad);
 198         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 199                 adsize = sizeof(long_ad);
 200         else
 201                 BUG();
 202
 203         etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
 204         byte_offset = (offset << sb->s_blocksize_bits) +
 205                 (inode->i_size & (sb->s_blocksize - 1));
 206         if (etype != -1) {
 207                 epos.offset -= adsize;
 208                 extent_trunc(inode, &epos, eloc, etype, elen, byte_offset);
 209                 epos.offset += adsize;
 210                 if (byte_offset)
 211                         lenalloc = epos.offset;
 212                 else
 213                         lenalloc = epos.offset - adsize;
 214
 215                 if (!epos.bh)
 216                         lenalloc -= udf_file_entry_alloc_offset(inode);
 217                 else
 218                         lenalloc -= sizeof(struct allocExtDesc);
 219
 220                 while ((etype = udf_current_aext(inode, &epos, &eloc,
 221                                                  &elen, 0)) != -1) {
 222                         if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
 223                                 udf_write_aext(inode, &epos, neloc, nelen, 0);
 224                                 if (indirect_ext_len) {
 225                                         /* We managed to free all extents in the
 226                                          * indirect extent - free it too */
 227                                         if (!epos.bh)
 228                                                 BUG();
 229                                         udf_free_blocks(sb, inode, epos.block,
 230                                                         0, indirect_ext_len);
 231                                 } else {
 232                                         if (!epos.bh) {
 233                                                 iinfo->i_lenAlloc =
 234                                                                 lenalloc;
 235                                                 mark_inode_dirty(inode);
 236                                         } else {
 237                                                 struct allocExtDesc *aed =
 238                                                         (struct allocExtDesc *)
 239                                                         (epos.bh->b_data);
 240                                                 int len =
 241                                                     sizeof(struct allocExtDesc);
 242
 243                                                 aed->lengthAllocDescs =
 244                                                     cpu_to_le32(lenalloc);
 245                                                 if (!UDF_QUERY_FLAG(sb,
 246                                                         UDF_FLAG_STRICT) ||
 247                                                     sbi->s_udfrev >= 0x0201)
 248                                                         len += lenalloc;
 249
 250                                                 udf_update_tag(epos.bh->b_data,
 251                                                                 len);
 252                                                 mark_buffer_dirty_inode(
 253                                                                 epos.bh, inode);
 254                                         }
 255                                 }
 256                                 brelse(epos.bh);
 257                                 epos.offset = sizeof(struct allocExtDesc);
 258                                 epos.block = eloc;
 259                                 epos.bh = udf_tread(sb,
 260                                                 udf_get_lb_pblock(sb, eloc, 0));
 261                                 if (elen)
 262                                         indirect_ext_len =
 263                                                 (elen + sb->s_blocksize - 1) >>
 264                                                 sb->s_blocksize_bits;
 265                                 else
 266                                         indirect_ext_len = 1;
 267                         } else {
 268                                 extent_trunc(inode, &epos, eloc, etype,
 269                                              elen, 0);
 270                                 epos.offset += adsize;
 271                         }
 272                 }
 273
 274                 if (indirect_ext_len) {
 275                         if (!epos.bh)
 276                                 BUG();
 277                         udf_free_blocks(sb, inode, epos.block, 0,
 278                                         indirect_ext_len);
 279                 } else {
 280                         if (!epos.bh) {
 281                                 iinfo->i_lenAlloc = lenalloc;
 282                                 mark_inode_dirty(inode);
 283                         } else {
 284                                 struct allocExtDesc *aed =
 285                                     (struct allocExtDesc *)(epos.bh->b_data);
 286                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 287                                 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) ||
 288                                     sbi->s_udfrev >= 0x0201)
 289                                         udf_update_tag(epos.bh->b_data,
 290                                                 lenalloc +
 291                                                 sizeof(struct allocExtDesc));
 292                                 else
 293                                         udf_update_tag(epos.bh->b_data,
 294                                                 sizeof(struct allocExtDesc));
 295                                 mark_buffer_dirty_inode(epos.bh, inode);
 296                         }
 297                 }
 298         } else if (inode->i_size) {
 299                 if (byte_offset) {
 300                         kernel_long_ad extent;
 301
 302                         /*
 303                          *  OK, there is not extent covering inode->i_size and
 304                          *  no extent above inode->i_size => truncate is
 305                          *  extending the file by 'offset' blocks.
 306                          */
 307                         if ((!epos.bh &&
 308                              epos.offset ==
 309                                         udf_file_entry_alloc_offset(inode)) ||
 310                             (epos.bh && epos.offset ==
 311                                                 sizeof(struct allocExtDesc))) {
 312                                 /* File has no extents at all or has empty last
 313                                  * indirect extent! Create a fake extent... */
 314                                 extent.extLocation.logicalBlockNum = 0;
 315                                 extent.extLocation.partitionReferenceNum = 0;
 316                                 extent.extLength =
 317                                         EXT_NOT_RECORDED_NOT_ALLOCATED;
 318                         } else {
 319                                 epos.offset -= adsize;
 320                                 etype = udf_next_aext(inode, &epos,
 321                                                       &extent.extLocation,
 322                                                       &extent.extLength, 0);
 323                                 extent.extLength |= etype << 30;
 324                         }
 325                         udf_extend_file(inode, &epos, &extent,
 326                                         offset +
 327                                         ((inode->i_size &
 328                                                 (sb->s_blocksize - 1)) != 0));
 329                 }
 330         }
 331         iinfo->i_lenExtents = inode->i_size;
 332
 333         brelse(epos.bh);
 334 }