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   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 #include <linux/udf_fs.h>
  26 #include <linux/buffer_head.h>
  27
  28 #include "udf_i.h"
  29 #include "udf_sb.h"
  30
  31 static void extent_trunc(struct inode * inode, kernel_lb_addr bloc, int extoffset,
  32         kernel_lb_addr eloc, int8_t etype, uint32_t elen, struct buffer_head *bh, uint32_t nelen)
  33 {
  34         kernel_lb_addr neloc = { 0, 0 };
  35         int last_block = (elen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
  36         int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
  37
  38         if (nelen)
  39         {
  40                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
  41                 {
  42                         udf_free_blocks(inode->i_sb, inode, eloc, 0, last_block);
  43                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
  44                 }
  45                 else
  46                         neloc = eloc;
  47                 nelen = (etype << 30) | nelen;
  48         }
  49
  50         if (elen != nelen)
  51         {
  52                 udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 0);
  53                 if (last_block - first_block > 0)
  54                 {
  55                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
  56                                 mark_inode_dirty(inode);
  57
  58                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
  59                                 udf_free_blocks(inode->i_sb, inode, eloc, first_block, last_block - first_block);
  60                 }
  61         }
  62 }
  63
  64 void udf_discard_prealloc(struct inode * inode)
  65 {
  66         kernel_lb_addr bloc, eloc;
  67         uint32_t extoffset = 0, elen, nelen;
  68         uint64_t lbcount = 0;
  69         int8_t etype = -1, netype;
  70         struct buffer_head *bh = NULL;
  71         int adsize;
  72
  73         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB ||
  74                 inode->i_size == UDF_I_LENEXTENTS(inode))
  75         {
  76                 return;
  77         }
  78
  79         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
  80                 adsize = sizeof(short_ad);
  81         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
  82                 adsize = sizeof(long_ad);
  83         else
  84                 adsize = 0;
  85
  86         bloc = UDF_I_LOCATION(inode);
  87
  88         while ((netype = udf_next_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 1)) != -1)
  89         {
  90                 etype = netype;
  91                 lbcount += elen;
  92                 if (lbcount > inode->i_size && lbcount - inode->i_size < inode->i_sb->s_blocksize)
  93                 {
  94                         nelen = elen - (lbcount - inode->i_size);
  95                         extent_trunc(inode, bloc, extoffset-adsize, eloc, etype, elen, bh, nelen);
  96                         lbcount = inode->i_size;
  97                 }
  98         }
  99         if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
 100         {
 101                 extoffset -= adsize;
 102                 lbcount -= elen;
 103                 extent_trunc(inode, bloc, extoffset, eloc, etype, elen, bh, 0);
 104                 if (!bh)
 105                 {
 106                         UDF_I_LENALLOC(inode) = extoffset - udf_file_entry_alloc_offset(inode);
 107                         mark_inode_dirty(inode);
 108                 }
 109                 else
 110                 {
 111                         struct allocExtDesc *aed = (struct allocExtDesc *)(bh->b_data);
 112                         aed->lengthAllocDescs = cpu_to_le32(extoffset - sizeof(struct allocExtDesc));
 113                         if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 114                                 udf_update_tag(bh->b_data, extoffset);
 115                         else
 116                                 udf_update_tag(bh->b_data, sizeof(struct allocExtDesc));
 117                         mark_buffer_dirty_inode(bh, inode);
 118                 }
 119         }
 120         UDF_I_LENEXTENTS(inode) = lbcount;
 121
 122         udf_release_data(bh);
 123 }
 124
 125 void udf_truncate_extents(struct inode * inode)
 126 {
 127         kernel_lb_addr bloc, eloc, neloc = { 0, 0 };
 128         uint32_t extoffset, elen, nelen = 0, lelen = 0, lenalloc;
 129         int8_t etype;
 130         sector_t first_block = inode->i_size >> inode->i_sb->s_blocksize_bits, offset;
 131         loff_t byte_offset;
 132         struct buffer_head *bh = NULL;
 133         int adsize;
 134
 135         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
 136                 adsize = sizeof(short_ad);
 137         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
 138                 adsize = sizeof(long_ad);
 139         else
 140                 adsize = 0;
 141
 142         etype = inode_bmap(inode, first_block, &bloc, &extoffset, &eloc, &elen, &offset, &bh);
 143         byte_offset = (offset << inode->i_sb->s_blocksize_bits) + (inode->i_size & (inode->i_sb->s_blocksize-1));
 144         if (etype != -1)
 145         {
 146                 extoffset -= adsize;
 147                 extent_trunc(inode, bloc, extoffset, eloc, etype, elen, bh, byte_offset);
 148                 extoffset += adsize;
 149
 150                 if (byte_offset)
 151                         lenalloc = extoffset;
 152                 else
 153                         lenalloc = extoffset - adsize;
 154
 155                 if (!bh)
 156                         lenalloc -= udf_file_entry_alloc_offset(inode);
 157                 else
 158                         lenalloc -= sizeof(struct allocExtDesc);
 159
 160                 while ((etype = udf_current_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 0)) != -1)
 161                 {
 162                         if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30))
 163                         {
 164                                 udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 0);
 165                                 extoffset = 0;
 166                                 if (lelen)
 167                                 {
 168                                         if (!bh)
 169                                                 BUG();
 170                                         else
 171                                                 memset(bh->b_data, 0x00, sizeof(struct allocExtDesc));
 172                                         udf_free_blocks(inode->i_sb, inode, bloc, 0, lelen);
 173                                 }
 174                                 else
 175                                 {
 176                                         if (!bh)
 177                                         {
 178                                                 UDF_I_LENALLOC(inode) = lenalloc;
 179                                                 mark_inode_dirty(inode);
 180                                         }
 181                                         else
 182                                         {
 183                                                 struct allocExtDesc *aed = (struct allocExtDesc *)(bh->b_data);
 184                                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 185                                                 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 186                                                         udf_update_tag(bh->b_data, lenalloc +
 187                                                                 sizeof(struct allocExtDesc));
 188                                                 else
 189                                                         udf_update_tag(bh->b_data, sizeof(struct allocExtDesc));
 190                                                 mark_buffer_dirty_inode(bh, inode);
 191                                         }
 192                                 }
 193
 194                                 udf_release_data(bh);
 195                                 extoffset = sizeof(struct allocExtDesc);
 196                                 bloc = eloc;
 197                                 bh = udf_tread(inode->i_sb, udf_get_lb_pblock(inode->i_sb, bloc, 0));
 198                                 if (elen)
 199                                         lelen = (elen + inode->i_sb->s_blocksize - 1) >>
 200                                                 inode->i_sb->s_blocksize_bits;
 201                                 else
 202                                         lelen = 1;
 203                         }
 204                         else
 205                         {
 206                                 extent_trunc(inode, bloc, extoffset, eloc, etype, elen, bh, 0);
 207                                 extoffset += adsize;
 208                         }
 209                 }
 210
 211                 if (lelen)
 212                 {
 213                         if (!bh)
 214                                 BUG();
 215                         else
 216                                 memset(bh->b_data, 0x00, sizeof(struct allocExtDesc));
 217                         udf_free_blocks(inode->i_sb, inode, bloc, 0, lelen);
 218                 }
 219                 else
 220                 {
 221                         if (!bh)
 222                         {
 223                                 UDF_I_LENALLOC(inode) = lenalloc;
 224                                 mark_inode_dirty(inode);
 225                         }
 226                         else
 227                         {
 228                                 struct allocExtDesc *aed = (struct allocExtDesc *)(bh->b_data);
 229                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 230                                 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 231                                         udf_update_tag(bh->b_data, lenalloc +
 232                                                 sizeof(struct allocExtDesc));
 233                                 else
 234                                         udf_update_tag(bh->b_data, sizeof(struct allocExtDesc));
 235                                 mark_buffer_dirty_inode(bh, inode);
 236                         }
 237                 }
 238         }
 239         else if (inode->i_size)
 240         {
 241                 if (byte_offset)
 242                 {
 243                         /*
 244                          *  OK, there is not extent covering inode->i_size and
 245                          *  no extent above inode->i_size => truncate is
 246                          *  extending the file by 'offset'.
 247                          */
 248                         if ((!bh && extoffset == udf_file_entry_alloc_offset(inode)) ||
 249                             (bh && extoffset == sizeof(struct allocExtDesc))) {
 250                                 /* File has no extents at all! */
 251                                 memset(&eloc, 0x00, sizeof(kernel_lb_addr));
 252                                 elen = EXT_NOT_RECORDED_NOT_ALLOCATED | byte_offset;
 253                                 udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
 254                         }
 255                         else {
 256                                 extoffset -= adsize;
 257                                 etype = udf_next_aext(inode, &bloc, &extoffset, &eloc, &elen, &bh, 1);
 258                                 if (etype == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
 259                                 {
 260                                         extoffset -= adsize;
 261                                         elen = EXT_NOT_RECORDED_NOT_ALLOCATED | (elen + byte_offset);
 262                                         udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 0);
 263                                 }
 264                                 else if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
 265                                 {
 266                                         kernel_lb_addr neloc = { 0, 0 };
 267                                         extoffset -= adsize;
 268                                         nelen = EXT_NOT_RECORDED_NOT_ALLOCATED |
 269                                                 ((elen + byte_offset + inode->i_sb->s_blocksize - 1) &
 270                                                 ~(inode->i_sb->s_blocksize - 1));
 271                                         udf_write_aext(inode, bloc, &extoffset, neloc, nelen, bh, 1);
 272                                         udf_add_aext(inode, &bloc, &extoffset, eloc, (etype << 30) | elen, &bh, 1);
 273                                 }
 274                                 else
 275                                 {
 276                                         if (elen & (inode->i_sb->s_blocksize - 1))
 277                                         {
 278                                                 extoffset -= adsize;
 279                                                 elen = EXT_RECORDED_ALLOCATED |
 280                                                         ((elen + inode->i_sb->s_blocksize - 1) &
 281                                                         ~(inode->i_sb->s_blocksize - 1));
 282                                                 udf_write_aext(inode, bloc, &extoffset, eloc, elen, bh, 1);
 283                                         }
 284                                         memset(&eloc, 0x00, sizeof(kernel_lb_addr));
 285                                         elen = EXT_NOT_RECORDED_NOT_ALLOCATED | byte_offset;
 286                                         udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 1);
 287                                 }
 288                         }
 289                 }
 290         }
 291         UDF_I_LENEXTENTS(inode) = inode->i_size;
 292
 293         udf_release_data(bh);
 294 }