fs/udf/truncate.c

   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 = { 0, 0 };
  36         int last_block =
  37             (elen + inode->i_sb->s_blocksize -
  38              1) >> inode->i_sb->s_blocksize_bits;
  39         int first_block =
  40             (nelen + inode->i_sb->s_blocksize -
  41              1) >> inode->i_sb->s_blocksize_bits;
  42
  43         if (nelen) {
  44                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
  45                         udf_free_blocks(inode->i_sb, inode, eloc, 0,
  46                                         last_block);
  47                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
  48                 } else
  49                         neloc = eloc;
  50                 nelen = (etype << 30) | nelen;
  51         }
  52
  53         if (elen != nelen) {
  54                 udf_write_aext(inode, epos, neloc, nelen, 0);
  55                 if (last_block - first_block > 0) {
  56                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
  57                                 mark_inode_dirty(inode);
  58
  59                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
  60                                 udf_free_blocks(inode->i_sb, inode, eloc,
  61                                                 first_block,
  62                                                 last_block - first_block);
  63                 }
  64         }
  65 }
  66
  67 /*
  68  * Truncate the last extent to match i_size. This function assumes
  69  * that preallocation extent is already truncated.
  70  */
  71 void udf_truncate_tail_extent(struct inode *inode)
  72 {
  73         struct extent_position epos = { NULL, 0, {0, 0} };
  74         kernel_lb_addr eloc;
  75         uint32_t elen, nelen;
  76         uint64_t lbcount = 0;
  77         int8_t etype = -1, netype;
  78         int adsize;
  79
  80         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB ||
  81             inode->i_size == UDF_I_LENEXTENTS(inode))
  82                 return;
  83         /* Are we going to delete the file anyway? */
  84         if (inode->i_nlink == 0)
  85                 return;
  86
  87         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
  88                 adsize = sizeof(short_ad);
  89         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
  90                 adsize = sizeof(long_ad);
  91         else
  92                 BUG();
  93
  94         /* Find the last extent in the file */
  95         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
  96                 etype = netype;
  97                 lbcount += elen;
  98                 if (lbcount > inode->i_size) {
  99                         if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
 100                                 printk(KERN_WARNING
 101                                        "udf_truncate_tail_extent(): Too long "
 102                                        "extent after EOF in inode %u: i_size: "
 103                                        "%Ld lbcount: %Ld extent %u+%u\n",
 104                                        (unsigned)inode->i_ino,
 105                                        (long long)inode->i_size,
 106                                        (long long)lbcount,
 107                                        (unsigned)eloc.logicalBlockNum,
 108                                        (unsigned)elen);
 109                         nelen = elen - (lbcount - inode->i_size);
 110                         epos.offset -= adsize;
 111                         extent_trunc(inode, &epos, eloc, etype, elen, nelen);
 112                         epos.offset += adsize;
 113                         if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
 114                                 printk(KERN_ERR "udf_truncate_tail_extent(): "
 115                                        "Extent after EOF in inode %u.\n",
 116                                        (unsigned)inode->i_ino);
 117                         break;
 118                 }
 119         }
 120         /* This inode entry is in-memory only and thus we don't have to mark
 121          * the inode dirty */
 122         UDF_I_LENEXTENTS(inode) = inode->i_size;
 123         brelse(epos.bh);
 124 }
 125
 126 void udf_discard_prealloc(struct inode *inode)
 127 {
 128         struct extent_position epos = { NULL, 0, {0, 0} };
 129         kernel_lb_addr eloc;
 130         uint32_t elen;
 131         uint64_t lbcount = 0;
 132         int8_t etype = -1, netype;
 133         int adsize;
 134
 135         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB ||
 136             inode->i_size == UDF_I_LENEXTENTS(inode))
 137                 return;
 138
 139         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
 140                 adsize = sizeof(short_ad);
 141         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
 142                 adsize = sizeof(long_ad);
 143         else
 144                 adsize = 0;
 145
 146         epos.block = UDF_I_LOCATION(inode);
 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                         UDF_I_LENALLOC(inode) =
 159                             epos.offset - udf_file_entry_alloc_offset(inode);
 160                         mark_inode_dirty(inode);
 161                 } else {
 162                         struct allocExtDesc *aed =
 163                             (struct allocExtDesc *)(epos.bh->b_data);
 164                         aed->lengthAllocDescs =
 165                             cpu_to_le32(epos.offset -
 166                                         sizeof(struct allocExtDesc));
 167                         if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT)
 168                             || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 169                                 udf_update_tag(epos.bh->b_data, epos.offset);
 170                         else
 171                                 udf_update_tag(epos.bh->b_data,
 172                                                sizeof(struct allocExtDesc));
 173                         mark_buffer_dirty_inode(epos.bh, inode);
 174                 }
 175         }
 176         /* This inode entry is in-memory only and thus we don't have to mark
 177          * the inode dirty */
 178         UDF_I_LENEXTENTS(inode) = lbcount;
 179         brelse(epos.bh);
 180 }
 181
 182 void udf_truncate_extents(struct inode *inode)
 183 {
 184         struct extent_position epos;
 185         kernel_lb_addr eloc, neloc = { 0, 0 };
 186         uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
 187         int8_t etype;
 188         struct super_block *sb = inode->i_sb;
 189         sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
 190         loff_t byte_offset;
 191         int adsize;
 192
 193         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
 194                 adsize = sizeof(short_ad);
 195         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
 196                 adsize = sizeof(long_ad);
 197         else
 198                 BUG();
 199
 200         etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
 201         byte_offset =
 202             (offset << sb->s_blocksize_bits) +
 203             (inode->i_size & (sb->s_blocksize - 1));
 204         if (etype != -1) {
 205                 epos.offset -= adsize;
 206                 extent_trunc(inode, &epos, eloc, etype, elen, byte_offset);
 207                 epos.offset += adsize;
 208                 if (byte_offset)
 209                         lenalloc = epos.offset;
 210                 else
 211                         lenalloc = epos.offset - adsize;
 212
 213                 if (!epos.bh)
 214                         lenalloc -= udf_file_entry_alloc_offset(inode);
 215                 else
 216                         lenalloc -= sizeof(struct allocExtDesc);
 217
 218                 while ((etype =
 219                         udf_current_aext(inode, &epos, &eloc, &elen,
 220                                          0)) != -1) {
 221                         if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
 222                                 udf_write_aext(inode, &epos, neloc, nelen, 0);
 223                                 if (indirect_ext_len) {
 224                                         /* We managed to free all extents in the
 225                                          * indirect extent - free it too */
 226                                         if (!epos.bh)
 227                                                 BUG();
 228                                         udf_free_blocks(sb, inode, epos.block,
 229                                                         0, indirect_ext_len);
 230                                 } else {
 231                                         if (!epos.bh) {
 232                                                 UDF_I_LENALLOC(inode) =
 233                                                     lenalloc;
 234                                                 mark_inode_dirty(inode);
 235                                         } else {
 236                                                 struct allocExtDesc *aed =
 237                                                     (struct allocExtDesc
 238                                                      *)(epos.bh->b_data);
 239                                                 aed->lengthAllocDescs =
 240                                                     cpu_to_le32(lenalloc);
 241                                                 if (!UDF_QUERY_FLAG
 242                                                     (sb, UDF_FLAG_STRICT)
 243                                                     || UDF_SB_UDFREV(sb) >=
 244                                                     0x0201)
 245                                                         udf_update_tag(epos.bh->
 246                                                                        b_data,
 247                                                                        lenalloc
 248                                                                        +
 249                                                                        sizeof
 250                                                                        (struct
 251                                                                         allocExtDesc));
 252                                                 else
 253                                                         udf_update_tag(epos.bh->
 254                                                                        b_data,
 255                                                                        sizeof
 256                                                                        (struct
 257                                                                         allocExtDesc));
 258                                                 mark_buffer_dirty_inode(epos.bh,
 259                                                                         inode);
 260                                         }
 261                                 }
 262                                 brelse(epos.bh);
 263                                 epos.offset = sizeof(struct allocExtDesc);
 264                                 epos.block = eloc;
 265                                 epos.bh =
 266                                     udf_tread(sb,
 267                                               udf_get_lb_pblock(sb, eloc, 0));
 268                                 if (elen)
 269                                         indirect_ext_len = (elen +
 270                                                             sb->s_blocksize -
 271                                                             1) >> sb->
 272                                             s_blocksize_bits;
 273                                 else
 274                                         indirect_ext_len = 1;
 275                         } else {
 276                                 extent_trunc(inode, &epos, eloc, etype, elen,
 277                                              0);
 278                                 epos.offset += adsize;
 279                         }
 280                 }
 281
 282                 if (indirect_ext_len) {
 283                         if (!epos.bh)
 284                                 BUG();
 285                         udf_free_blocks(sb, inode, epos.block, 0,
 286                                         indirect_ext_len);
 287                 } else {
 288                         if (!epos.bh) {
 289                                 UDF_I_LENALLOC(inode) = lenalloc;
 290                                 mark_inode_dirty(inode);
 291                         } else {
 292                                 struct allocExtDesc *aed =
 293                                     (struct allocExtDesc *)(epos.bh->b_data);
 294                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 295                                 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT)
 296                                     || UDF_SB_UDFREV(sb) >= 0x0201)
 297                                         udf_update_tag(epos.bh->b_data,
 298                                                        lenalloc +
 299                                                        sizeof(struct
 300                                                               allocExtDesc));
 301                                 else
 302                                         udf_update_tag(epos.bh->b_data,
 303                                                        sizeof(struct
 304                                                               allocExtDesc));
 305                                 mark_buffer_dirty_inode(epos.bh, inode);
 306                         }
 307                 }
 308         } else if (inode->i_size) {
 309                 if (byte_offset) {
 310                         kernel_long_ad extent;
 311
 312                         /*
 313                          *  OK, there is not extent covering inode->i_size and
 314                          *  no extent above inode->i_size => truncate is
 315                          *  extending the file by 'offset' blocks.
 316                          */
 317                         if ((!epos.bh
 318                              && epos.offset ==
 319                              udf_file_entry_alloc_offset(inode)) || (epos.bh
 320                                                                      && epos.
 321                                                                      offset ==
 322                                                                      sizeof
 323                                                                      (struct
 324                                                                       allocExtDesc)))
 325                         {
 326                                 /* File has no extents at all or has empty last
 327                                  * indirect extent! Create a fake extent... */
 328                                 extent.extLocation.logicalBlockNum = 0;
 329                                 extent.extLocation.partitionReferenceNum = 0;
 330                                 extent.extLength =
 331                                     EXT_NOT_RECORDED_NOT_ALLOCATED;
 332                         } else {
 333                                 epos.offset -= adsize;
 334                                 etype = udf_next_aext(inode, &epos,
 335                                                       &extent.extLocation,
 336                                                       &extent.extLength, 0);
 337                                 extent.extLength |= etype << 30;
 338                         }
 339                         udf_extend_file(inode, &epos, &extent,
 340                                         offset +
 341                                         ((inode->
 342                                           i_size & (sb->s_blocksize - 1)) !=
 343                                          0));
 344                 }
 345         }
 346         UDF_I_LENEXTENTS(inode) = inode->i_size;
 347
 348         brelse(epos.bh);
 349 }