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                                 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         iinfo->i_lenExtents = 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         struct kernel_lb_addr eloc;
 128         uint32_t elen;
 129         uint64_t lbcount = 0;
 130         int8_t etype = -1, netype;
 131         int adsize;
 132         struct udf_inode_info *iinfo = UDF_I(inode);
 133
 134         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
 135             inode->i_size == iinfo->i_lenExtents)
 136                 return;
 137
 138         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 139                 adsize = sizeof(struct short_ad);
 140         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 141                 adsize = sizeof(struct long_ad);
 142         else
 143                 adsize = 0;
 144
 145         epos.block = iinfo->i_location;
 146
 147         /* Find the last extent in the file */
 148         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
 149                 etype = netype;
 150                 lbcount += elen;
 151         }
 152         if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
 153                 epos.offset -= adsize;
 154                 lbcount -= elen;
 155                 extent_trunc(inode, &epos, &eloc, etype, elen, 0);
 156                 if (!epos.bh) {
 157                         iinfo->i_lenAlloc =
 158                                 epos.offset -
 159                                 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(inode->i_sb)->s_udfrev >= 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         iinfo->i_lenExtents = lbcount;
 179         brelse(epos.bh);
 180 }
 181
 182 static void udf_update_alloc_ext_desc(struct inode *inode,
 183                                       struct extent_position *epos,
 184                                       u32 lenalloc)
 185 {
 186         struct super_block *sb = inode->i_sb;
 187         struct udf_sb_info *sbi = UDF_SB(sb);
 188
 189         struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
 190         int len = sizeof(struct allocExtDesc);
 191
 192         aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 193         if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
 194                 len += lenalloc;
 195
 196         udf_update_tag(epos->bh->b_data, len);
 197         mark_buffer_dirty_inode(epos->bh, inode);
 198 }
 199
 200 /*
 201  * Truncate extents of inode to inode->i_size. This function can be used only
 202  * for making file shorter. For making file longer, udf_extend_file() has to
 203  * be used.
 204  */
 205 void udf_truncate_extents(struct inode *inode)
 206 {
 207         struct extent_position epos;
 208         struct kernel_lb_addr eloc, neloc = {};
 209         uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
 210         int8_t etype;
 211         struct super_block *sb = inode->i_sb;
 212         sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
 213         loff_t byte_offset;
 214         int adsize;
 215         struct udf_inode_info *iinfo = UDF_I(inode);
 216
 217         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 218                 adsize = sizeof(struct short_ad);
 219         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 220                 adsize = sizeof(struct long_ad);
 221         else
 222                 BUG();
 223
 224         etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
 225         byte_offset = (offset << sb->s_blocksize_bits) +
 226                 (inode->i_size & (sb->s_blocksize - 1));
 227         if (etype == -1) {
 228                 /* We should extend the file? */
 229                 WARN_ON(byte_offset);
 230                 return;
 231         }
 232         epos.offset -= adsize;
 233         extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
 234         epos.offset += adsize;
 235         if (byte_offset)
 236                 lenalloc = epos.offset;
 237         else
 238                 lenalloc = epos.offset - adsize;
 239
 240         if (!epos.bh)
 241                 lenalloc -= udf_file_entry_alloc_offset(inode);
 242         else
 243                 lenalloc -= sizeof(struct allocExtDesc);
 244
 245         while ((etype = udf_current_aext(inode, &epos, &eloc,
 246                                          &elen, 0)) != -1) {
 247                 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
 248                         udf_write_aext(inode, &epos, &neloc, nelen, 0);
 249                         if (indirect_ext_len) {
 250                                 /* We managed to free all extents in the
 251                                  * indirect extent - free it too */
 252                                 BUG_ON(!epos.bh);
 253                                 udf_free_blocks(sb, inode, &epos.block,
 254                                                 0, indirect_ext_len);
 255                         } else if (!epos.bh) {
 256                                 iinfo->i_lenAlloc = lenalloc;
 257                                 mark_inode_dirty(inode);
 258                         } else
 259                                 udf_update_alloc_ext_desc(inode,
 260                                                 &epos, lenalloc);
 261                         brelse(epos.bh);
 262                         epos.offset = sizeof(struct allocExtDesc);
 263                         epos.block = eloc;
 264                         epos.bh = udf_tread(sb,
 265                                         udf_get_lb_pblock(sb, &eloc, 0));
 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, inode, &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 }