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) 1999-2004 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 #include <linux/buffer_head.h>
  32
  33 #include "udf_i.h"
  34 #include "udf_sb.h"
  35
  36 static void extent_trunc(struct inode * inode, kernel_lb_addr bloc, int extoffset,
  37         kernel_lb_addr eloc, int8_t etype, uint32_t elen, struct buffer_head *bh, uint32_t nelen)
  38 {
  39         kernel_lb_addr neloc = { 0, 0 };
  40         int last_block = (elen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
  41         int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
  42
  43         if (nelen)
  44         {
  45                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
  46                 {
  47                         udf_free_blocks(inode->i_sb, inode, eloc, 0, last_block);
  48                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
  49                 }
  50                 else
  51                         neloc = eloc;
  52                 nelen = (etype << 30) | nelen;
  53         }
  54
  55         if (elen != nelen)
  56         {
  57                 udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 0);
  58                 if (last_block - first_block > 0)
  59                 {
  60                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
  61                                 mark_inode_dirty(inode);
  62
  63                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
  64                                 udf_free_blocks(inode->i_sb, inode, eloc, first_block, last_block - first_block);
  65                 }
  66         }
  67 }
  68
  69 void udf_discard_prealloc(struct inode * inode)
  70 {
  71         kernel_lb_addr bloc, eloc;
  72         uint32_t extoffset = 0, elen, nelen;
  73         uint64_t lbcount = 0;
  74         int8_t etype = -1, netype;
  75         struct buffer_head *bh = NULL;
  76         int adsize;
  77
  78         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB ||
  79                 inode->i_size == UDF_I_LENEXTENTS(inode))
  80         {
  81                 return;
  82         }
  83
  84         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
  85                 adsize = sizeof(short_ad);
  86         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
  87                 adsize = sizeof(long_ad);
  88         else
  89                 adsize = 0;
  90
  91         bloc = UDF_I_LOCATION(inode);
  92
  93         while ((netype = udf_next_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 1)) != -1)
  94         {
  95                 etype = netype;
  96                 lbcount += elen;
  97                 if (lbcount > inode->i_size && lbcount - inode->i_size < inode->i_sb->s_blocksize)
  98                 {
  99                         nelen = elen - (lbcount - inode->i_size);
 100                         extent_trunc(inode, bloc, extoffset-adsize, eloc, etype, elen, bh, nelen);
 101                         lbcount = inode->i_size;
 102                 }
 103         }
 104         if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
 105         {
 106                 extoffset -= adsize;
 107                 lbcount -= elen;
 108                 extent_trunc(inode, bloc, extoffset, eloc, etype, elen, bh, 0);
 109                 if (!bh)
 110                 {
 111                         UDF_I_LENALLOC(inode) = extoffset - udf_file_entry_alloc_offset(inode);
 112                         mark_inode_dirty(inode);
 113                 }
 114                 else
 115                 {
 116                         struct allocExtDesc *aed = (struct allocExtDesc *)(bh->b_data);
 117                         aed->lengthAllocDescs = cpu_to_le32(extoffset - sizeof(struct allocExtDesc));
 118                         if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 119                                 udf_update_tag(bh->b_data, extoffset);
 120                         else
 121                                 udf_update_tag(bh->b_data, sizeof(struct allocExtDesc));
 122                         mark_buffer_dirty_inode(bh, inode);
 123                 }
 124         }
 125         UDF_I_LENEXTENTS(inode) = lbcount;
 126
 127         udf_release_data(bh);
 128 }
 129
 130 void udf_truncate_extents(struct inode * inode)
 131 {
 132         kernel_lb_addr bloc, eloc, neloc = { 0, 0 };
 133         uint32_t extoffset, elen, offset, nelen = 0, lelen = 0, lenalloc;
 134         int8_t etype;
 135         int first_block = inode->i_size >> inode->i_sb->s_blocksize_bits;
 136         struct buffer_head *bh = NULL;
 137         int adsize;
 138
 139         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
 140                 adsize = sizeof(short_ad);
 141         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
 142                 adsize = sizeof(long_ad);
 143         else
 144                 adsize = 0;
 145
 146         etype = inode_bmap(inode, first_block, &bloc, &extoffset, &eloc, &elen, &offset, &bh);
 147         offset += (inode->i_size & (inode->i_sb->s_blocksize - 1));
 148         if (etype != -1)
 149         {
 150                 extoffset -= adsize;
 151                 extent_trunc(inode, bloc, extoffset, eloc, etype, elen, bh, offset);
 152                 extoffset += adsize;
 153
 154                 if (offset)
 155                         lenalloc = extoffset;
 156                 else
 157                         lenalloc = extoffset - adsize;
 158
 159                 if (!bh)
 160                         lenalloc -= udf_file_entry_alloc_offset(inode);
 161                 else
 162                         lenalloc -= sizeof(struct allocExtDesc);
 163
 164                 while ((etype = udf_current_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 0)) != -1)
 165                 {
 166                         if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30))
 167                         {
 168                                 udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 0);
 169                                 extoffset = 0;
 170                                 if (lelen)
 171                                 {
 172                                         if (!bh)
 173                                                 BUG();
 174                                         else
 175                                                 memset(bh->b_data, 0x00, sizeof(struct allocExtDesc));
 176                                         udf_free_blocks(inode->i_sb, inode, bloc, 0, lelen);
 177                                 }
 178                                 else
 179                                 {
 180                                         if (!bh)
 181                                         {
 182                                                 UDF_I_LENALLOC(inode) = lenalloc;
 183                                                 mark_inode_dirty(inode);
 184                                         }
 185                                         else
 186                                         {
 187                                                 struct allocExtDesc *aed = (struct allocExtDesc *)(bh->b_data);
 188                                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 189                                                 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 190                                                         udf_update_tag(bh->b_data, lenalloc +
 191                                                                 sizeof(struct allocExtDesc));
 192                                                 else
 193                                                         udf_update_tag(bh->b_data, sizeof(struct allocExtDesc));
 194                                                 mark_buffer_dirty_inode(bh, inode);
 195                                         }
 196                                 }
 197
 198                                 udf_release_data(bh);
 199                                 extoffset = sizeof(struct allocExtDesc);
 200                                 bloc = eloc;
 201                                 bh = udf_tread(inode->i_sb, udf_get_lb_pblock(inode->i_sb, bloc, 0));
 202                                 if (elen)
 203                                         lelen = (elen + inode->i_sb->s_blocksize - 1) >>
 204                                                 inode->i_sb->s_blocksize_bits;
 205                                 else
 206                                         lelen = 1;
 207                         }
 208                         else
 209                         {
 210                                 extent_trunc(inode, bloc, extoffset, eloc, etype, elen, bh, 0);
 211                                 extoffset += adsize;
 212                         }
 213                 }
 214
 215                 if (lelen)
 216                 {
 217                         if (!bh)
 218                                 BUG();
 219                         else
 220                                 memset(bh->b_data, 0x00, sizeof(struct allocExtDesc));
 221                         udf_free_blocks(inode->i_sb, inode, bloc, 0, lelen);
 222                 }
 223                 else
 224                 {
 225                         if (!bh)
 226                         {
 227                                 UDF_I_LENALLOC(inode) = lenalloc;
 228                                 mark_inode_dirty(inode);
 229                         }
 230                         else
 231                         {
 232                                 struct allocExtDesc *aed = (struct allocExtDesc *)(bh->b_data);
 233                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 234                                 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 235                                         udf_update_tag(bh->b_data, lenalloc +
 236                                                 sizeof(struct allocExtDesc));
 237                                 else
 238                                         udf_update_tag(bh->b_data, sizeof(struct allocExtDesc));
 239                                 mark_buffer_dirty_inode(bh, inode);
 240                         }
 241                 }
 242         }
 243         else if (inode->i_size)
 244         {
 245                 if (offset)
 246                 {
 247                         extoffset -= adsize;
 248                         etype = udf_next_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 1);
 249                         if (etype == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
 250                         {
 251                                 extoffset -= adsize;
 252                                 elen = EXT_NOT_RECORDED_NOT_ALLOCATED | (elen + offset);
 253                                 udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 0);
 254                         }
 255                         else if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
 256                         {
 257                                 kernel_lb_addr neloc = { 0, 0 };
 258                                 extoffset -= adsize;
 259                                 nelen = EXT_NOT_RECORDED_NOT_ALLOCATED |
 260                                         ((elen + offset + inode->i_sb->s_blocksize - 1) &
 261                                         ~(inode->i_sb->s_blocksize - 1));
 262                                 udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 1);
 263                                 udf_add_aext(inode, &bloc, &extoffset, eloc, (etype << 30) | elen, &bh, 1);
 264                         }
 265                         else
 266                         {
 267                                 if (elen & (inode->i_sb->s_blocksize - 1))
 268                                 {
 269                                         extoffset -= adsize;
 270                                         elen = EXT_RECORDED_ALLOCATED |
 271                                                 ((elen + inode->i_sb->s_blocksize - 1) &
 272                                                 ~(inode->i_sb->s_blocksize - 1));
 273                                         udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 1);
 274                                 }
 275                                 memset(&eloc, 0x00, sizeof(kernel_lb_addr));
 276                                 elen = EXT_NOT_RECORDED_NOT_ALLOCATED | offset;
 277                                 udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
 278                         }
 279                 }
 280         }
 281         UDF_I_LENEXTENTS(inode) = inode->i_size;
 282
 283         udf_release_data(bh);
 284 }