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