fs/udf/truncate.c

   1 /*
   2  * truncate.c
   3  *
   4  * PURPOSE
   5  *      Truncate handling routines for the OSTA-UDF(tm) filesystem.
   6  *
   7  * CONTACTS
   8  *      E-mail regarding any portion of the Linux UDF file system should be
   9  *      directed to the development team mailing list (run by majordomo):
  10  *              linux_udf@hpesjro.fc.hp.com
  11  *
  12  * COPYRIGHT
  13  *      This file is distributed under the terms of the GNU General Public
  14  *      License (GPL). Copies of the GPL can be obtained from:
  15  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  16  *      Each contributing author retains all rights to their own work.
  17  *
  18  *  (C) 1999-2001 Ben Fennema
  19  *  (C) 1999 Stelias Computing Inc
  20  *
  21  * HISTORY
  22  *
  23  *  02/24/99 blf  Created.
  24  *
  25  */
  26
  27 #include "udfdecl.h"
  28 #include <linux/fs.h>
  29 #include <linux/mm.h>
  30 #include <linux/udf_fs.h>
  31
  32 #include "udf_i.h"
  33 #include "udf_sb.h"
  34
  35 static void extent_trunc(struct inode * inode, lb_addr bloc, int extoffset,
  36         lb_addr eloc, int8_t etype, uint32_t elen, struct buffer_head *bh, uint32_t nelen)
  37 {
  38         lb_addr neloc = { 0, 0 };
  39         int last_block = (elen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
  40         int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
  41
  42         if (nelen)
  43         {
  44                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
  45                 {
  46                         udf_free_blocks(inode->i_sb, inode, eloc, 0, last_block);
  47                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
  48                 }
  49                 else
  50                         neloc = eloc;
  51                 nelen = (etype << 30) | nelen;
  52         }
  53
  54         if (elen != nelen)
  55         {
  56                 udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 0);
  57                 if (last_block - first_block > 0)
  58                 {
  59                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
  60                                 mark_inode_dirty(inode);
  61
  62                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
  63                                 udf_free_blocks(inode->i_sb, inode, eloc, first_block, last_block - first_block);
  64                 }
  65         }
  66 }
  67
  68 void udf_truncate_extents(struct inode * inode)
  69 {
  70         lb_addr bloc, eloc, neloc = { 0, 0 };
  71         uint32_t extoffset, elen, offset, nelen = 0, lelen = 0, lenalloc;
  72         int8_t etype;
  73         int first_block = inode->i_size >> inode->i_sb->s_blocksize_bits;
  74         struct buffer_head *bh = NULL;
  75         int adsize;
  76
  77         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
  78                 adsize = sizeof(short_ad);
  79         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
  80                 adsize = sizeof(long_ad);
  81         else
  82                 adsize = 0;
  83
  84         etype = inode_bmap(inode, first_block, &bloc, &extoffset, &eloc, &elen, &offset, &bh);
  85         offset += (inode->i_size & (inode->i_sb->s_blocksize - 1));
  86         if (etype != -1)
  87         {
  88                 extoffset -= adsize;
  89                 extent_trunc(inode, bloc, extoffset, eloc, etype, elen, bh, offset);
  90                 extoffset += adsize;
  91
  92                 if (offset)
  93                         lenalloc = extoffset;
  94                 else
  95                         lenalloc = extoffset - adsize;
  96
  97                 if (!memcmp(&UDF_I_LOCATION(inode), &bloc, sizeof(lb_addr)))
  98                         lenalloc -= udf_file_entry_alloc_offset(inode);
  99                 else
 100                         lenalloc -= sizeof(struct allocExtDesc);
 101
 102                 while ((etype = udf_current_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 0)) != -1)
 103                 {
 104                         if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30))
 105                         {
 106                                 udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 0);
 107                                 extoffset = 0;
 108                                 if (lelen)
 109                                 {
 110                                         if (!memcmp(&UDF_I_LOCATION(inode), &bloc, sizeof(lb_addr)))
 111                                                 memset(bh->b_data, 0x00, udf_file_entry_alloc_offset(inode));
 112                                         else
 113                                                 memset(bh->b_data, 0x00, sizeof(struct allocExtDesc));
 114                                         udf_free_blocks(inode->i_sb, inode, bloc, 0, lelen);
 115                                 }
 116                                 else
 117                                 {
 118                                         if (!memcmp(&UDF_I_LOCATION(inode), &bloc, sizeof(lb_addr)))
 119                                         {
 120                                                 UDF_I_LENALLOC(inode) = lenalloc;
 121                                                 mark_inode_dirty(inode);
 122                                         }
 123                                         else
 124                                         {
 125                                                 struct allocExtDesc *aed = (struct allocExtDesc *)(bh->b_data);
 126                                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 127                                                 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 128                                                         udf_update_tag(bh->b_data, lenalloc +
 129                                                                 sizeof(struct allocExtDesc));
 130                                                 else
 131                                                         udf_update_tag(bh->b_data, sizeof(struct allocExtDesc));
 132                                                 mark_buffer_dirty_inode(bh, inode);
 133                                         }
 134                                 }
 135
 136                                 udf_release_data(bh);
 137                                 bh = NULL;
 138
 139                                 bloc = eloc;
 140                                 if (elen)
 141                                         lelen = (elen + inode->i_sb->s_blocksize - 1) >>
 142                                                 inode->i_sb->s_blocksize_bits;
 143                                 else
 144                                         lelen = 1;
 145                         }
 146                         else
 147                         {
 148                                 extent_trunc(inode, bloc, extoffset, eloc, etype, elen, bh, 0);
 149                                 extoffset += adsize;
 150                         }
 151                 }
 152
 153                 if (lelen)
 154                 {
 155                         if (!memcmp(&UDF_I_LOCATION(inode), &bloc, sizeof(lb_addr)))
 156                                 memset(bh->b_data, 0x00, udf_file_entry_alloc_offset(inode));
 157                         else
 158                                 memset(bh->b_data, 0x00, sizeof(struct allocExtDesc));
 159                         udf_free_blocks(inode->i_sb, inode, bloc, 0, lelen);
 160                 }
 161                 else
 162                 {
 163                         if (!memcmp(&UDF_I_LOCATION(inode), &bloc, sizeof(lb_addr)))
 164                         {
 165                                 UDF_I_LENALLOC(inode) = lenalloc;
 166                                 mark_inode_dirty(inode);
 167                         }
 168                         else
 169                         {
 170                                 struct allocExtDesc *aed = (struct allocExtDesc *)(bh->b_data);
 171                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 172                                 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 173                                         udf_update_tag(bh->b_data, lenalloc +
 174                                                 sizeof(struct allocExtDesc));
 175                                 else
 176                                         udf_update_tag(bh->b_data, sizeof(struct allocExtDesc));
 177                                 mark_buffer_dirty_inode(bh, inode);
 178                         }
 179                 }
 180         }
 181         else if (inode->i_size)
 182         {
 183                 if (offset)
 184                 {
 185                         /*
 186                          *  OK, there is not extent covering inode->i_size and
 187                          *  no extent above inode->i_size => truncate is
 188                          *  extending the file by 'offset'.
 189                          */
 190                         if ((!bh && extoffset == udf_file_entry_alloc_offset(inode)) ||
 191                             (bh && extoffset == sizeof(struct allocExtDesc))) {
 192                                 /* File has no extents at all! */
 193                                 memset(&eloc, 0x00, sizeof(lb_addr));
 194                                 elen = EXT_NOT_RECORDED_NOT_ALLOCATED | offset;
 195                                 udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
 196                         }
 197                         else {
 198                                 extoffset -= adsize;
 199                                 etype = udf_next_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 1);
 200                                 if (etype == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
 201                                 {
 202                                         extoffset -= adsize;
 203                                         elen = EXT_NOT_RECORDED_NOT_ALLOCATED | (elen + offset);
 204                                         udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 0);
 205                                 }
 206                                 else if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
 207                                 {
 208                                         lb_addr neloc = { 0, 0 };
 209                                         extoffset -= adsize;
 210                                         nelen = EXT_NOT_RECORDED_NOT_ALLOCATED |
 211                                                 ((elen + offset + inode->i_sb->s_blocksize - 1) &
 212                                                 ~(inode->i_sb->s_blocksize - 1));
 213                                         udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 1);
 214                                         udf_add_aext(inode, &bloc, &extoffset, eloc, (etype << 30) | elen, &bh, 1);
 215                                 }
 216                                 else
 217                                 {
 218                                         if (elen & (inode->i_sb->s_blocksize - 1))
 219                                         {
 220                                                 extoffset -= adsize;
 221                                                 elen = EXT_RECORDED_ALLOCATED |
 222                                                         ((elen + inode->i_sb->s_blocksize - 1) &
 223                                                         ~(inode->i_sb->s_blocksize - 1));
 224                                                 udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 1);
 225                                         }
 226                                         memset(&eloc, 0x00, sizeof(lb_addr));
 227                                         elen = EXT_NOT_RECORDED_NOT_ALLOCATED | offset;
 228                                         udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
 229                                 }
 230                         }
 231                 }
 232         }
 233         UDF_I_LENEXTENTS(inode) = inode->i_size;
 234
 235         udf_release_data(bh);
 236 }