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
  26 #include "udf_i.h"
  27 #include "udf_sb.h"
  28
  29 static void extent_trunc(struct inode *inode, struct extent_position *epos,
  30                          struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
  31                          uint32_t nelen)
  32 {
  33         struct kernel_lb_addr neloc = {};
  34         int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
  35                 inode->i_sb->s_blocksize_bits;
  36         int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
  37                 inode->i_sb->s_blocksize_bits;
  38
  39         if (nelen) {
  40                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
  41                         udf_free_blocks(inode->i_sb, inode, eloc, 0,
  42                                         last_block);
  43                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
  44                 } else
  45                         neloc = *eloc;
  46                 nelen = (etype << 30) | nelen;
  47         }
  48
  49         if (elen != nelen) {
  50                 udf_write_aext(inode, epos, &neloc, nelen, 0);
  51                 if (last_block > first_block) {
  52                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
  53                                 mark_inode_dirty(inode);
  54
  55                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
  56                                 udf_free_blocks(inode->i_sb, inode, eloc,
  57                                                 first_block,
  58                                                 last_block - first_block);
  59                 }
  60         }
  61 }
  62
  63 /*
  64  * Truncate the last extent to match i_size. This function assumes
  65  * that preallocation extent is already truncated.
  66  */
  67 void udf_truncate_tail_extent(struct inode *inode)
  68 {
  69         struct extent_position epos = {};
  70         struct kernel_lb_addr eloc;
  71         uint32_t elen, nelen;
  72         uint64_t lbcount = 0;
  73         int8_t etype = -1, netype;
  74         int adsize;
  75         struct udf_inode_info *iinfo = UDF_I(inode);
  76
  77         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
  78             inode->i_size == iinfo->i_lenExtents)
  79                 return;
  80         /* Are we going to delete the file anyway? */
  81         if (inode->i_nlink == 0)
  82                 return;
  83
  84         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  85                 adsize = sizeof(struct short_ad);
  86         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
  87                 adsize = sizeof(struct 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                 etype = netype;
  94                 lbcount += elen;
  95                 if (lbcount > inode->i_size) {
  96                         if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
  97                                 udf_warn(inode->i_sb,
  98                                          "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n",
  99                                          (unsigned)inode->i_ino,
 100                                          (long long)inode->i_size,
 101                                          (long long)lbcount,
 102                                          (unsigned)eloc.logicalBlockNum,
 103                                          (unsigned)elen);
 104                         nelen = elen - (lbcount - inode->i_size);
 105                         epos.offset -= adsize;
 106                         extent_trunc(inode, &epos, &eloc, etype, elen, nelen);
 107                         epos.offset += adsize;
 108                         if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
 109                                 udf_err(inode->i_sb,
 110                                         "Extent after EOF in inode %u\n",
 111                                         (unsigned)inode->i_ino);
 112                         break;
 113                 }
 114         }
 115         /* This inode entry is in-memory only and thus we don't have to mark
 116          * the inode dirty */
 117         iinfo->i_lenExtents = inode->i_size;
 118         brelse(epos.bh);
 119 }
 120
 121 void udf_discard_prealloc(struct inode *inode)
 122 {
 123         struct extent_position epos = { NULL, 0, {0, 0} };
 124         struct kernel_lb_addr eloc;
 125         uint32_t elen;
 126         uint64_t lbcount = 0;
 127         int8_t etype = -1, netype;
 128         int adsize;
 129         struct udf_inode_info *iinfo = UDF_I(inode);
 130
 131         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
 132             inode->i_size == iinfo->i_lenExtents)
 133                 return;
 134
 135         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 136                 adsize = sizeof(struct short_ad);
 137         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 138                 adsize = sizeof(struct long_ad);
 139         else
 140                 adsize = 0;
 141
 142         epos.block = iinfo->i_location;
 143
 144         /* Find the last extent in the file */
 145         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
 146                 etype = netype;
 147                 lbcount += elen;
 148         }
 149         if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
 150                 epos.offset -= adsize;
 151                 lbcount -= elen;
 152                 extent_trunc(inode, &epos, &eloc, etype, elen, 0);
 153                 if (!epos.bh) {
 154                         iinfo->i_lenAlloc =
 155                                 epos.offset -
 156                                 udf_file_entry_alloc_offset(inode);
 157                         mark_inode_dirty(inode);
 158                 } else {
 159                         struct allocExtDesc *aed =
 160                                 (struct allocExtDesc *)(epos.bh->b_data);
 161                         aed->lengthAllocDescs =
 162                                 cpu_to_le32(epos.offset -
 163                                             sizeof(struct allocExtDesc));
 164                         if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) ||
 165                             UDF_SB(inode->i_sb)->s_udfrev >= 0x0201)
 166                                 udf_update_tag(epos.bh->b_data, epos.offset);
 167                         else
 168                                 udf_update_tag(epos.bh->b_data,
 169                                                sizeof(struct allocExtDesc));
 170                         mark_buffer_dirty_inode(epos.bh, inode);
 171                 }
 172         }
 173         /* This inode entry is in-memory only and thus we don't have to mark
 174          * the inode dirty */
 175         iinfo->i_lenExtents = lbcount;
 176         brelse(epos.bh);
 177 }
 178
 179 static void udf_update_alloc_ext_desc(struct inode *inode,
 180                                       struct extent_position *epos,
 181                                       u32 lenalloc)
 182 {
 183         struct super_block *sb = inode->i_sb;
 184         struct udf_sb_info *sbi = UDF_SB(sb);
 185
 186         struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
 187         int len = sizeof(struct allocExtDesc);
 188
 189         aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 190         if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
 191                 len += lenalloc;
 192
 193         udf_update_tag(epos->bh->b_data, len);
 194         mark_buffer_dirty_inode(epos->bh, inode);
 195 }
 196
 197 /*
 198  * Truncate extents of inode to inode->i_size. This function can be used only
 199  * for making file shorter. For making file longer, udf_extend_file() has to
 200  * be used.
 201  */
 202 int udf_truncate_extents(struct inode *inode)
 203 {
 204         struct extent_position epos;
 205         struct kernel_lb_addr eloc, neloc = {};
 206         uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
 207         int8_t etype;
 208         struct super_block *sb = inode->i_sb;
 209         sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
 210         loff_t byte_offset;
 211         int adsize;
 212         struct udf_inode_info *iinfo = UDF_I(inode);
 213
 214         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 215                 adsize = sizeof(struct short_ad);
 216         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 217                 adsize = sizeof(struct long_ad);
 218         else
 219                 BUG();
 220
 221         etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
 222         byte_offset = (offset << sb->s_blocksize_bits) +
 223                 (inode->i_size & (sb->s_blocksize - 1));
 224         if (etype == -1) {
 225                 /* We should extend the file? */
 226                 WARN_ON(byte_offset);
 227                 return 0;
 228         }
 229         epos.offset -= adsize;
 230         extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
 231         epos.offset += adsize;
 232         if (byte_offset)
 233                 lenalloc = epos.offset;
 234         else
 235                 lenalloc = epos.offset - adsize;
 236
 237         if (!epos.bh)
 238                 lenalloc -= udf_file_entry_alloc_offset(inode);
 239         else
 240                 lenalloc -= sizeof(struct allocExtDesc);
 241
 242         while ((etype = udf_current_aext(inode, &epos, &eloc,
 243                                          &elen, 0)) != -1) {
 244                 if (etype == (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) {
 245                         udf_write_aext(inode, &epos, &neloc, nelen, 0);
 246                         if (indirect_ext_len) {
 247                                 /* We managed to free all extents in the
 248                                  * indirect extent - free it too */
 249                                 BUG_ON(!epos.bh);
 250                                 udf_free_blocks(sb, NULL, &epos.block,
 251                                                 0, indirect_ext_len);
 252                         } else if (!epos.bh) {
 253                                 iinfo->i_lenAlloc = lenalloc;
 254                                 mark_inode_dirty(inode);
 255                         } else
 256                                 udf_update_alloc_ext_desc(inode,
 257                                                 &epos, lenalloc);
 258                         brelse(epos.bh);
 259                         epos.offset = sizeof(struct allocExtDesc);
 260                         epos.block = eloc;
 261                         epos.bh = udf_tread(sb,
 262                                         udf_get_lb_pblock(sb, &eloc, 0));
 263                         /* Error reading indirect block? */
 264                         if (!epos.bh)
 265                                 return -EIO;
 266                         if (elen)
 267                                 indirect_ext_len =
 268                                         (elen + sb->s_blocksize - 1) >>
 269                                         sb->s_blocksize_bits;
 270                         else
 271                                 indirect_ext_len = 1;
 272                 } else {
 273                         extent_trunc(inode, &epos, &eloc, etype, elen, 0);
 274                         epos.offset += adsize;
 275                 }
 276         }
 277
 278         if (indirect_ext_len) {
 279                 BUG_ON(!epos.bh);
 280                 udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
 281         } else if (!epos.bh) {
 282                 iinfo->i_lenAlloc = lenalloc;
 283                 mark_inode_dirty(inode);
 284         } else
 285                 udf_update_alloc_ext_desc(inode, &epos, lenalloc);
 286         iinfo->i_lenExtents = inode->i_size;
 287
 288         brelse(epos.bh);
 289         return 0;
 290 }