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/buffer_head.h>
  26
  27 #include "udf_i.h"
  28 #include "udf_sb.h"
  29
  30 static void extent_trunc(struct inode *inode, struct extent_position *epos,
  31                          struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
  32                          uint32_t nelen)
  33 {
  34         struct kernel_lb_addr neloc = {};
  35         int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
  36                 inode->i_sb->s_blocksize_bits;
  37         int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
  38                 inode->i_sb->s_blocksize_bits;
  39
  40         if (nelen) {
  41                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
  42                         udf_free_blocks(inode->i_sb, inode, eloc, 0,
  43                                         last_block);
  44                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
  45                 } else
  46                         neloc = *eloc;
  47                 nelen = (etype << 30) | nelen;
  48         }
  49
  50         if (elen != nelen) {
  51                 udf_write_aext(inode, epos, &neloc, nelen, 0);
  52                 if (last_block - first_block > 0) {
  53                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
  54                                 mark_inode_dirty(inode);
  55
  56                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
  57                                 udf_free_blocks(inode->i_sb, inode, eloc,
  58                                                 first_block,
  59                                                 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 = {};
  71         struct kernel_lb_addr eloc;
  72         uint32_t elen, nelen;
  73         uint64_t lbcount = 0;
  74         int8_t etype = -1, netype;
  75         int adsize;
  76         struct udf_inode_info *iinfo = UDF_I(inode);
  77
  78         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
  79             inode->i_size == iinfo->i_lenExtents)
  80                 return;
  81         /* Are we going to delete the file anyway? */
  82         if (inode->i_nlink == 0)
  83                 return;
  84
  85         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  86                 adsize = sizeof(struct short_ad);
  87         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
  88                 adsize = sizeof(struct long_ad);
  89         else
  90                 BUG();
  91
  92         /* Find the last extent in the file */
  93         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
  94                 etype = netype;
  95                 lbcount += elen;
  96                 if (lbcount > inode->i_size) {
  97                         if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
  98                                 udf_warn(inode->i_sb,
  99                                          "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n",
 100                                          (unsigned)inode->i_ino,
 101                                          (long long)inode->i_size,
 102                                          (long long)lbcount,
 103                                          (unsigned)eloc.logicalBlockNum,
 104                                          (unsigned)elen);
 105                         nelen = elen - (lbcount - inode->i_size);
 106                         epos.offset -= adsize;
 107                         extent_trunc(inode, &epos, &eloc, etype, elen, nelen);
 108                         epos.offset += adsize;
 109                         if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
 110                                 udf_err(inode->i_sb,
 111                                         "Extent after EOF in inode %u\n",
 112                                         (unsigned)inode->i_ino);
 113                         break;
 114                 }
 115         }
 116         /* This inode entry is in-memory only and thus we don't have to mark
 117          * the inode dirty */
 118         iinfo->i_lenExtents = inode->i_size;
 119         brelse(epos.bh);
 120 }
 121
 122 void udf_discard_prealloc(struct inode *inode)
 123 {
 124         struct extent_position epos = { NULL, 0, {0, 0} };
 125         struct kernel_lb_addr eloc;
 126         uint32_t elen;
 127         uint64_t lbcount = 0;
 128         int8_t etype = -1, netype;
 129         int adsize;
 130         struct udf_inode_info *iinfo = UDF_I(inode);
 131
 132         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
 133             inode->i_size == iinfo->i_lenExtents)
 134                 return;
 135
 136         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 137                 adsize = sizeof(struct short_ad);
 138         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 139                 adsize = sizeof(struct long_ad);
 140         else
 141                 adsize = 0;
 142
 143         epos.block = iinfo->i_location;
 144
 145         /* Find the last extent in the file */
 146         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
 147                 etype = netype;
 148                 lbcount += elen;
 149         }
 150         if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
 151                 epos.offset -= adsize;
 152                 lbcount -= elen;
 153                 extent_trunc(inode, &epos, &eloc, etype, elen, 0);
 154                 if (!epos.bh) {
 155                         iinfo->i_lenAlloc =
 156                                 epos.offset -
 157                                 udf_file_entry_alloc_offset(inode);
 158                         mark_inode_dirty(inode);
 159                 } else {
 160                         struct allocExtDesc *aed =
 161                                 (struct allocExtDesc *)(epos.bh->b_data);
 162                         aed->lengthAllocDescs =
 163                                 cpu_to_le32(epos.offset -
 164                                             sizeof(struct allocExtDesc));
 165                         if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) ||
 166                             UDF_SB(inode->i_sb)->s_udfrev >= 0x0201)
 167                                 udf_update_tag(epos.bh->b_data, epos.offset);
 168                         else
 169                                 udf_update_tag(epos.bh->b_data,
 170                                                sizeof(struct allocExtDesc));
 171                         mark_buffer_dirty_inode(epos.bh, inode);
 172                 }
 173         }
 174         /* This inode entry is in-memory only and thus we don't have to mark
 175          * the inode dirty */
 176         iinfo->i_lenExtents = lbcount;
 177         brelse(epos.bh);
 178 }
 179
 180 static void udf_update_alloc_ext_desc(struct inode *inode,
 181                                       struct extent_position *epos,
 182                                       u32 lenalloc)
 183 {
 184         struct super_block *sb = inode->i_sb;
 185         struct udf_sb_info *sbi = UDF_SB(sb);
 186
 187         struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
 188         int len = sizeof(struct allocExtDesc);
 189
 190         aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 191         if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
 192                 len += lenalloc;
 193
 194         udf_update_tag(epos->bh->b_data, len);
 195         mark_buffer_dirty_inode(epos->bh, inode);
 196 }
 197
 198 /*
 199  * Truncate extents of inode to inode->i_size. This function can be used only
 200  * for making file shorter. For making file longer, udf_extend_file() has to
 201  * be used.
 202  */
 203 void udf_truncate_extents(struct inode *inode)
 204 {
 205         struct extent_position epos;
 206         struct kernel_lb_addr eloc, neloc = {};
 207         uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
 208         int8_t etype;
 209         struct super_block *sb = inode->i_sb;
 210         sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
 211         loff_t byte_offset;
 212         int adsize;
 213         struct udf_inode_info *iinfo = UDF_I(inode);
 214
 215         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 216                 adsize = sizeof(struct short_ad);
 217         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 218                 adsize = sizeof(struct long_ad);
 219         else
 220                 BUG();
 221
 222         etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
 223         byte_offset = (offset << sb->s_blocksize_bits) +
 224                 (inode->i_size & (sb->s_blocksize - 1));
 225         if (etype == -1) {
 226                 /* We should extend the file? */
 227                 WARN_ON(byte_offset);
 228                 return;
 229         }
 230         epos.offset -= adsize;
 231         extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
 232         epos.offset += adsize;
 233         if (byte_offset)
 234                 lenalloc = epos.offset;
 235         else
 236                 lenalloc = epos.offset - adsize;
 237
 238         if (!epos.bh)
 239                 lenalloc -= udf_file_entry_alloc_offset(inode);
 240         else
 241                 lenalloc -= sizeof(struct allocExtDesc);
 242
 243         while ((etype = udf_current_aext(inode, &epos, &eloc,
 244                                          &elen, 0)) != -1) {
 245                 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
 246                         udf_write_aext(inode, &epos, &neloc, nelen, 0);
 247                         if (indirect_ext_len) {
 248                                 /* We managed to free all extents in the
 249                                  * indirect extent - free it too */
 250                                 BUG_ON(!epos.bh);
 251                                 udf_free_blocks(sb, inode, &epos.block,
 252                                                 0, indirect_ext_len);
 253                         } else if (!epos.bh) {
 254                                 iinfo->i_lenAlloc = lenalloc;
 255                                 mark_inode_dirty(inode);
 256                         } else
 257                                 udf_update_alloc_ext_desc(inode,
 258                                                 &epos, lenalloc);
 259                         brelse(epos.bh);
 260                         epos.offset = sizeof(struct allocExtDesc);
 261                         epos.block = eloc;
 262                         epos.bh = udf_tread(sb,
 263                                         udf_get_lb_pblock(sb, &eloc, 0));
 264                         if (elen)
 265                                 indirect_ext_len =
 266                                         (elen + sb->s_blocksize - 1) >>
 267                                         sb->s_blocksize_bits;
 268                         else
 269                                 indirect_ext_len = 1;
 270                 } else {
 271                         extent_trunc(inode, &epos, &eloc, etype, elen, 0);
 272                         epos.offset += adsize;
 273                 }
 274         }
 275
 276         if (indirect_ext_len) {
 277                 BUG_ON(!epos.bh);
 278                 udf_free_blocks(sb, inode, &epos.block, 0, indirect_ext_len);
 279         } else if (!epos.bh) {
 280                 iinfo->i_lenAlloc = lenalloc;
 281                 mark_inode_dirty(inode);
 282         } else
 283                 udf_update_alloc_ext_desc(inode, &epos, lenalloc);
 284         iinfo->i_lenExtents = inode->i_size;
 285
 286         brelse(epos.bh);
 287 }