linux/fs/udf/truncate.c
<<
>>
Prefs
   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
  29static 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 > 0) {
  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 */
  67void 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
 121void 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
 179static 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 */
 202void 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;
 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_ALLOCDECS >> 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                        if (elen)
 264                                indirect_ext_len =
 265                                        (elen + sb->s_blocksize - 1) >>
 266                                        sb->s_blocksize_bits;
 267                        else
 268                                indirect_ext_len = 1;
 269                } else {
 270                        extent_trunc(inode, &epos, &eloc, etype, elen, 0);
 271                        epos.offset += adsize;
 272                }
 273        }
 274
 275        if (indirect_ext_len) {
 276                BUG_ON(!epos.bh);
 277                udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
 278        } else if (!epos.bh) {
 279                iinfo->i_lenAlloc = lenalloc;
 280                mark_inode_dirty(inode);
 281        } else
 282                udf_update_alloc_ext_desc(inode, &epos, lenalloc);
 283        iinfo->i_lenExtents = inode->i_size;
 284
 285        brelse(epos.bh);
 286}
 287