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, struct extent_position *epos, 32 kernel_lb_addr eloc, int8_t etype, uint32_t elen, 33 uint32_t nelen) 34 { 35 kernel_lb_addr neloc = {}; 36 int last_block = (elen + inode->i_sb->s_blocksize - 1) >> 37 inode->i_sb->s_blocksize_bits; 38 int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> 39 inode->i_sb->s_blocksize_bits; 40 41 if (nelen) { 42 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { 43 udf_free_blocks(inode->i_sb, inode, eloc, 0, 44 last_block); 45 etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30); 46 } else 47 neloc = eloc; 48 nelen = (etype << 30) | nelen; 49 } 50 51 if (elen != nelen) { 52 udf_write_aext(inode, epos, neloc, nelen, 0); 53 if (last_block - first_block > 0) { 54 if (etype == (EXT_RECORDED_ALLOCATED >> 30)) 55 mark_inode_dirty(inode); 56 57 if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30)) 58 udf_free_blocks(inode->i_sb, inode, eloc, 59 first_block, 60 last_block - first_block); 61 } 62 } 63 } 64 65 /* 66 * Truncate the last extent to match i_size. This function assumes 67 * that preallocation extent is already truncated. 68 */ 69 void udf_truncate_tail_extent(struct inode *inode) 70 { 71 struct extent_position epos = {}; 72 kernel_lb_addr eloc; 73 uint32_t elen, nelen; 74 uint64_t lbcount = 0; 75 int8_t etype = -1, netype; 76 int adsize; 77 struct udf_inode_info *iinfo = UDF_I(inode); 78 79 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB || 80 inode->i_size == iinfo->i_lenExtents) 81 return; 82 /* Are we going to delete the file anyway? */ 83 if (inode->i_nlink == 0) 84 return; 85 86 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 87 adsize = sizeof(short_ad); 88 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 89 adsize = sizeof(long_ad); 90 else 91 BUG(); 92 93 /* Find the last extent in the file */ 94 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) { 95 etype = netype; 96 lbcount += elen; 97 if (lbcount > inode->i_size) { 98 if (lbcount - inode->i_size >= inode->i_sb->s_blocksize) 99 printk(KERN_WARNING 100 "udf_truncate_tail_extent(): Too long " 101 "extent after EOF in inode %u: i_size: " 102 "%Ld lbcount: %Ld extent %u+%u\n", 103 (unsigned)inode->i_ino, 104 (long long)inode->i_size, 105 (long long)lbcount, 106 (unsigned)eloc.logicalBlockNum, 107 (unsigned)elen); 108 nelen = elen - (lbcount - inode->i_size); 109 epos.offset -= adsize; 110 extent_trunc(inode, &epos, eloc, etype, elen, nelen); 111 epos.offset += adsize; 112 if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1) 113 printk(KERN_ERR "udf_truncate_tail_extent(): " 114 "Extent after EOF in inode %u.\n", 115 (unsigned)inode->i_ino); 116 break; 117 } 118 } 119 /* This inode entry is in-memory only and thus we don't have to mark 120 * the inode dirty */ 121 iinfo->i_lenExtents = inode->i_size; 122 brelse(epos.bh); 123 } 124 125 void udf_discard_prealloc(struct inode *inode) 126 { 127 struct extent_position epos = { NULL, 0, {0, 0} }; 128 kernel_lb_addr eloc; 129 uint32_t elen; 130 uint64_t lbcount = 0; 131 int8_t etype = -1, netype; 132 int adsize; 133 struct udf_inode_info *iinfo = UDF_I(inode); 134 135 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB || 136 inode->i_size == iinfo->i_lenExtents) 137 return; 138 139 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 140 adsize = sizeof(short_ad); 141 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 142 adsize = sizeof(long_ad); 143 else 144 adsize = 0; 145 146 epos.block = iinfo->i_location; 147 148 /* Find the last extent in the file */ 149 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) { 150 etype = netype; 151 lbcount += elen; 152 } 153 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { 154 epos.offset -= adsize; 155 lbcount -= elen; 156 extent_trunc(inode, &epos, eloc, etype, elen, 0); 157 if (!epos.bh) { 158 iinfo->i_lenAlloc = 159 epos.offset - 160 udf_file_entry_alloc_offset(inode); 161 mark_inode_dirty(inode); 162 } else { 163 struct allocExtDesc *aed = 164 (struct allocExtDesc *)(epos.bh->b_data); 165 aed->lengthAllocDescs = 166 cpu_to_le32(epos.offset - 167 sizeof(struct allocExtDesc)); 168 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || 169 UDF_SB(inode->i_sb)->s_udfrev >= 0x0201) 170 udf_update_tag(epos.bh->b_data, epos.offset); 171 else 172 udf_update_tag(epos.bh->b_data, 173 sizeof(struct allocExtDesc)); 174 mark_buffer_dirty_inode(epos.bh, inode); 175 } 176 } 177 /* This inode entry is in-memory only and thus we don't have to mark 178 * the inode dirty */ 179 iinfo->i_lenExtents = lbcount; 180 brelse(epos.bh); 181 } 182 183 void udf_truncate_extents(struct inode *inode) 184 { 185 struct extent_position epos; 186 kernel_lb_addr eloc, neloc = {}; 187 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc; 188 int8_t etype; 189 struct super_block *sb = inode->i_sb; 190 struct udf_sb_info *sbi = UDF_SB(sb); 191 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset; 192 loff_t byte_offset; 193 int adsize; 194 struct udf_inode_info *iinfo = UDF_I(inode); 195 196 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 197 adsize = sizeof(short_ad); 198 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 199 adsize = sizeof(long_ad); 200 else 201 BUG(); 202 203 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset); 204 byte_offset = (offset << sb->s_blocksize_bits) + 205 (inode->i_size & (sb->s_blocksize - 1)); 206 if (etype != -1) { 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_ALLOCDECS >> 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 if (!epos.bh) 228 BUG(); 229 udf_free_blocks(sb, inode, epos.block, 230 0, indirect_ext_len); 231 } else { 232 if (!epos.bh) { 233 iinfo->i_lenAlloc = 234 lenalloc; 235 mark_inode_dirty(inode); 236 } else { 237 struct allocExtDesc *aed = 238 (struct allocExtDesc *) 239 (epos.bh->b_data); 240 int len = 241 sizeof(struct allocExtDesc); 242 243 aed->lengthAllocDescs = 244 cpu_to_le32(lenalloc); 245 if (!UDF_QUERY_FLAG(sb, 246 UDF_FLAG_STRICT) || 247 sbi->s_udfrev >= 0x0201) 248 len += lenalloc; 249 250 udf_update_tag(epos.bh->b_data, 251 len); 252 mark_buffer_dirty_inode( 253 epos.bh, inode); 254 } 255 } 256 brelse(epos.bh); 257 epos.offset = sizeof(struct allocExtDesc); 258 epos.block = eloc; 259 epos.bh = udf_tread(sb, 260 udf_get_lb_pblock(sb, eloc, 0)); 261 if (elen) 262 indirect_ext_len = 263 (elen + sb->s_blocksize - 1) >> 264 sb->s_blocksize_bits; 265 else 266 indirect_ext_len = 1; 267 } else { 268 extent_trunc(inode, &epos, eloc, etype, 269 elen, 0); 270 epos.offset += adsize; 271 } 272 } 273 274 if (indirect_ext_len) { 275 if (!epos.bh) 276 BUG(); 277 udf_free_blocks(sb, inode, epos.block, 0, 278 indirect_ext_len); 279 } else { 280 if (!epos.bh) { 281 iinfo->i_lenAlloc = lenalloc; 282 mark_inode_dirty(inode); 283 } else { 284 struct allocExtDesc *aed = 285 (struct allocExtDesc *)(epos.bh->b_data); 286 aed->lengthAllocDescs = cpu_to_le32(lenalloc); 287 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || 288 sbi->s_udfrev >= 0x0201) 289 udf_update_tag(epos.bh->b_data, 290 lenalloc + 291 sizeof(struct allocExtDesc)); 292 else 293 udf_update_tag(epos.bh->b_data, 294 sizeof(struct allocExtDesc)); 295 mark_buffer_dirty_inode(epos.bh, inode); 296 } 297 } 298 } else if (inode->i_size) { 299 if (byte_offset) { 300 kernel_long_ad extent; 301 302 /* 303 * OK, there is not extent covering inode->i_size and 304 * no extent above inode->i_size => truncate is 305 * extending the file by 'offset' blocks. 306 */ 307 if ((!epos.bh && 308 epos.offset == 309 udf_file_entry_alloc_offset(inode)) || 310 (epos.bh && epos.offset == 311 sizeof(struct allocExtDesc))) { 312 /* File has no extents at all or has empty last 313 * indirect extent! Create a fake extent... */ 314 extent.extLocation.logicalBlockNum = 0; 315 extent.extLocation.partitionReferenceNum = 0; 316 extent.extLength = 317 EXT_NOT_RECORDED_NOT_ALLOCATED; 318 } else { 319 epos.offset -= adsize; 320 etype = udf_next_aext(inode, &epos, 321 &extent.extLocation, 322 &extent.extLength, 0); 323 extent.extLength |= etype << 30; 324 } 325 udf_extend_file(inode, &epos, &extent, 326 offset + 327 ((inode->i_size & 328 (sb->s_blocksize - 1)) != 0)); 329 } 330 } 331 iinfo->i_lenExtents = inode->i_size; 332 333 brelse(epos.bh); 334 } 335