fs/udf/truncate.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * truncate.c
   4  *
   5  * PURPOSE
   6  *      Truncate handling routines for the OSTA-UDF(tm) filesystem.
   7  *
   8  * COPYRIGHT
   9  *  (C) 1999-2004 Ben Fennema
  10  *  (C) 1999 Stelias Computing Inc
  11  *
  12  * HISTORY
  13  *
  14  *  02/24/99 blf  Created.
  15  *
  16  */
  17
  18 #include "udfdecl.h"
  19 #include <linux/fs.h>
  20 #include <linux/mm.h>
  21
  22 #include "udf_i.h"
  23 #include "udf_sb.h"
  24
  25 static void extent_trunc(struct inode *inode, struct extent_position *epos,
  26                          struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
  27                          uint32_t nelen)
  28 {
  29         struct kernel_lb_addr neloc = {};
  30         int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
  31                 inode->i_sb->s_blocksize_bits;
  32         int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
  33                 inode->i_sb->s_blocksize_bits;
  34
  35         if (nelen) {
  36                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
  37                         udf_free_blocks(inode->i_sb, inode, eloc, 0,
  38                                         last_block);
  39                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
  40                 } else
  41                         neloc = *eloc;
  42                 nelen = (etype << 30) | nelen;
  43         }
  44
  45         if (elen != nelen) {
  46                 udf_write_aext(inode, epos, &neloc, nelen, 0);
  47                 if (last_block > first_block) {
  48                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
  49                                 mark_inode_dirty(inode);
  50
  51                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
  52                                 udf_free_blocks(inode->i_sb, inode, eloc,
  53                                                 first_block,
  54                                                 last_block - first_block);
  55                 }
  56         }
  57 }
  58
  59 /*
  60  * Truncate the last extent to match i_size. This function assumes
  61  * that preallocation extent is already truncated.
  62  */
  63 void udf_truncate_tail_extent(struct inode *inode)
  64 {
  65         struct extent_position epos = {};
  66         struct kernel_lb_addr eloc;
  67         uint32_t elen, nelen;
  68         uint64_t lbcount = 0;
  69         int8_t etype = -1, netype;
  70         int adsize;
  71         struct udf_inode_info *iinfo = UDF_I(inode);
  72         int ret;
  73
  74         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
  75             inode->i_size == iinfo->i_lenExtents)
  76                 return;
  77         /* Are we going to delete the file anyway? */
  78         if (inode->i_nlink == 0)
  79                 return;
  80
  81         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  82                 adsize = sizeof(struct short_ad);
  83         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
  84                 adsize = sizeof(struct long_ad);
  85         else
  86                 BUG();
  87
  88         /* Find the last extent in the file */
  89         while (1) {
  90                 ret = udf_next_aext(inode, &epos, &eloc, &elen, &netype, 1);
  91                 if (ret <= 0)
  92                         break;
  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,
 109                                           &netype, 1) > 0)
 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         if (ret == 0)
 119                 iinfo->i_lenExtents = inode->i_size;
 120         brelse(epos.bh);
 121 }
 122
 123 void udf_discard_prealloc(struct inode *inode)
 124 {
 125         struct extent_position epos = {};
 126         struct extent_position prev_epos = {};
 127         struct kernel_lb_addr eloc;
 128         uint32_t elen;
 129         uint64_t lbcount = 0;
 130         int8_t etype = -1;
 131         struct udf_inode_info *iinfo = UDF_I(inode);
 132         int bsize = i_blocksize(inode);
 133         int8_t tmpetype = -1;
 134         int ret;
 135
 136         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
 137             ALIGN(inode->i_size, bsize) == ALIGN(iinfo->i_lenExtents, bsize))
 138                 return;
 139
 140         epos.block = iinfo->i_location;
 141
 142         /* Find the last extent in the file */
 143         while (1) {
 144                 ret = udf_next_aext(inode, &epos, &eloc, &elen, &tmpetype, 0);
 145                 if (ret < 0)
 146                         goto out;
 147                 if (ret == 0)
 148                         break;
 149                 brelse(prev_epos.bh);
 150                 prev_epos = epos;
 151                 if (prev_epos.bh)
 152                         get_bh(prev_epos.bh);
 153
 154                 ret = udf_next_aext(inode, &epos, &eloc, &elen, &etype, 1);
 155                 if (ret < 0)
 156                         goto out;
 157                 lbcount += elen;
 158         }
 159
 160         if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
 161                 lbcount -= elen;
 162                 udf_delete_aext(inode, prev_epos);
 163                 udf_free_blocks(inode->i_sb, inode, &eloc, 0,
 164                                 DIV_ROUND_UP(elen, bsize));
 165         }
 166         /* This inode entry is in-memory only and thus we don't have to mark
 167          * the inode dirty */
 168         iinfo->i_lenExtents = lbcount;
 169 out:
 170         brelse(epos.bh);
 171         brelse(prev_epos.bh);
 172 }
 173
 174 static void udf_update_alloc_ext_desc(struct inode *inode,
 175                                       struct extent_position *epos,
 176                                       u32 lenalloc)
 177 {
 178         struct super_block *sb = inode->i_sb;
 179         struct udf_sb_info *sbi = UDF_SB(sb);
 180
 181         struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
 182         int len = sizeof(struct allocExtDesc);
 183
 184         aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 185         if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
 186                 len += lenalloc;
 187
 188         udf_update_tag(epos->bh->b_data, len);
 189         mark_buffer_dirty_inode(epos->bh, inode);
 190 }
 191
 192 /*
 193  * Truncate extents of inode to inode->i_size. This function can be used only
 194  * for making file shorter. For making file longer, udf_extend_file() has to
 195  * be used.
 196  */
 197 int udf_truncate_extents(struct inode *inode)
 198 {
 199         struct extent_position epos;
 200         struct kernel_lb_addr eloc, neloc = {};
 201         uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
 202         int8_t etype;
 203         struct super_block *sb = inode->i_sb;
 204         sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
 205         loff_t byte_offset;
 206         int adsize;
 207         struct udf_inode_info *iinfo = UDF_I(inode);
 208         int ret = 0;
 209
 210         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 211                 adsize = sizeof(struct short_ad);
 212         else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 213                 adsize = sizeof(struct long_ad);
 214         else
 215                 BUG();
 216
 217         ret = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset, &etype);
 218         if (ret < 0)
 219                 return ret;
 220         byte_offset = (offset << sb->s_blocksize_bits) +
 221                 (inode->i_size & (sb->s_blocksize - 1));
 222         if (ret == 0) {
 223                 /* We should extend the file? */
 224                 WARN_ON(byte_offset);
 225                 return 0;
 226         }
 227         epos.offset -= adsize;
 228         extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
 229         epos.offset += adsize;
 230         if (byte_offset)
 231                 lenalloc = epos.offset;
 232         else
 233                 lenalloc = epos.offset - adsize;
 234
 235         if (!epos.bh)
 236                 lenalloc -= udf_file_entry_alloc_offset(inode);
 237         else
 238                 lenalloc -= sizeof(struct allocExtDesc);
 239
 240         while ((ret = udf_current_aext(inode, &epos, &eloc,
 241                                        &elen, &etype, 0)) > 0) {
 242                 if (etype == (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) {
 243                         udf_write_aext(inode, &epos, &neloc, nelen, 0);
 244                         if (indirect_ext_len) {
 245                                 /* We managed to free all extents in the
 246                                  * indirect extent - free it too */
 247                                 BUG_ON(!epos.bh);
 248                                 udf_free_blocks(sb, NULL, &epos.block,
 249                                                 0, indirect_ext_len);
 250                         } else if (!epos.bh) {
 251                                 iinfo->i_lenAlloc = lenalloc;
 252                                 mark_inode_dirty(inode);
 253                         } else
 254                                 udf_update_alloc_ext_desc(inode,
 255                                                 &epos, lenalloc);
 256                         brelse(epos.bh);
 257                         epos.offset = sizeof(struct allocExtDesc);
 258                         epos.block = eloc;
 259                         epos.bh = sb_bread(sb,
 260                                         udf_get_lb_pblock(sb, &eloc, 0));
 261                         /* Error reading indirect block? */
 262                         if (!epos.bh)
 263                                 return -EIO;
 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 (ret < 0) {
 277                 brelse(epos.bh);
 278                 return ret;
 279         }
 280
 281         if (indirect_ext_len) {
 282                 BUG_ON(!epos.bh);
 283                 udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
 284         } else if (!epos.bh) {
 285                 iinfo->i_lenAlloc = lenalloc;
 286                 mark_inode_dirty(inode);
 287         } else
 288                 udf_update_alloc_ext_desc(inode, &epos, lenalloc);
 289         iinfo->i_lenExtents = inode->i_size;
 290
 291         brelse(epos.bh);
 292         return 0;
 293 }