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