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 78 if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB || 79 inode->i_size == UDF_I_LENEXTENTS(inode)) 80 return; 81 /* Are we going to delete the file anyway? */ 82 if (inode->i_nlink == 0) 83 return; 84 85 if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT) 86 adsize = sizeof(short_ad); 87 else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG) 88 adsize = sizeof(long_ad); 89 else 90 BUG(); 91 92 /* Find the last extent in the file */ 93 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) { 94 etype = netype; 95 lbcount += elen; 96 if (lbcount > inode->i_size) { 97 if (lbcount - inode->i_size >= inode->i_sb->s_blocksize) 98 printk(KERN_WARNING 99 "udf_truncate_tail_extent(): Too long " 100 "extent after EOF in inode %u: i_size: " 101 "%Ld lbcount: %Ld extent %u+%u\n", 102 (unsigned)inode->i_ino, 103 (long long)inode->i_size, 104 (long long)lbcount, 105 (unsigned)eloc.logicalBlockNum, 106 (unsigned)elen); 107 nelen = elen - (lbcount - inode->i_size); 108 epos.offset -= adsize; 109 extent_trunc(inode, &epos, eloc, etype, elen, nelen); 110 epos.offset += adsize; 111 if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1) 112 printk(KERN_ERR "udf_truncate_tail_extent(): " 113 "Extent after EOF in inode %u.\n", 114 (unsigned)inode->i_ino); 115 break; 116 } 117 } 118 /* This inode entry is in-memory only and thus we don't have to mark 119 * the inode dirty */ 120 UDF_I_LENEXTENTS(inode) = inode->i_size; 121 brelse(epos.bh); 122 } 123 124 void udf_discard_prealloc(struct inode *inode) 125 { 126 struct extent_position epos = { NULL, 0, {0, 0} }; 127 kernel_lb_addr eloc; 128 uint32_t elen; 129 uint64_t lbcount = 0; 130 int8_t etype = -1, netype; 131 int adsize; 132 133 if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB || 134 inode->i_size == UDF_I_LENEXTENTS(inode)) 135 return; 136 137 if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT) 138 adsize = sizeof(short_ad); 139 else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG) 140 adsize = sizeof(long_ad); 141 else 142 adsize = 0; 143 144 epos.block = UDF_I_LOCATION(inode); 145 146 /* Find the last extent in the file */ 147 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) { 148 etype = netype; 149 lbcount += elen; 150 } 151 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { 152 epos.offset -= adsize; 153 lbcount -= elen; 154 extent_trunc(inode, &epos, eloc, etype, elen, 0); 155 if (!epos.bh) { 156 UDF_I_LENALLOC(inode) = 157 epos.offset - udf_file_entry_alloc_offset(inode); 158 mark_inode_dirty(inode); 159 } else { 160 struct allocExtDesc *aed = 161 (struct allocExtDesc *)(epos.bh->b_data); 162 aed->lengthAllocDescs = 163 cpu_to_le32(epos.offset - 164 sizeof(struct allocExtDesc)); 165 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || 166 UDF_SB_UDFREV(inode->i_sb) >= 0x0201) 167 udf_update_tag(epos.bh->b_data, epos.offset); 168 else 169 udf_update_tag(epos.bh->b_data, 170 sizeof(struct allocExtDesc)); 171 mark_buffer_dirty_inode(epos.bh, inode); 172 } 173 } 174 /* This inode entry is in-memory only and thus we don't have to mark 175 * the inode dirty */ 176 UDF_I_LENEXTENTS(inode) = lbcount; 177 brelse(epos.bh); 178 } 179 180 void udf_truncate_extents(struct inode *inode) 181 { 182 struct extent_position epos; 183 kernel_lb_addr eloc, neloc = {}; 184 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc; 185 int8_t etype; 186 struct super_block *sb = inode->i_sb; 187 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset; 188 loff_t byte_offset; 189 int adsize; 190 191 if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT) 192 adsize = sizeof(short_ad); 193 else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG) 194 adsize = sizeof(long_ad); 195 else 196 BUG(); 197 198 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset); 199 byte_offset = (offset << sb->s_blocksize_bits) + 200 (inode->i_size & (sb->s_blocksize - 1)); 201 if (etype != -1) { 202 epos.offset -= adsize; 203 extent_trunc(inode, &epos, eloc, etype, elen, byte_offset); 204 epos.offset += adsize; 205 if (byte_offset) 206 lenalloc = epos.offset; 207 else 208 lenalloc = epos.offset - adsize; 209 210 if (!epos.bh) 211 lenalloc -= udf_file_entry_alloc_offset(inode); 212 else 213 lenalloc -= sizeof(struct allocExtDesc); 214 215 while ((etype = udf_current_aext(inode, &epos, &eloc, &elen, 0)) != -1) { 216 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) { 217 udf_write_aext(inode, &epos, neloc, nelen, 0); 218 if (indirect_ext_len) { 219 /* We managed to free all extents in the 220 * indirect extent - free it too */ 221 if (!epos.bh) 222 BUG(); 223 udf_free_blocks(sb, inode, epos.block, 224 0, indirect_ext_len); 225 } else { 226 if (!epos.bh) { 227 UDF_I_LENALLOC(inode) = lenalloc; 228 mark_inode_dirty(inode); 229 } else { 230 struct allocExtDesc *aed = 231 (struct allocExtDesc *)(epos.bh->b_data); 232 aed->lengthAllocDescs = 233 cpu_to_le32(lenalloc); 234 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || 235 UDF_SB_UDFREV(sb) >= 0x0201) 236 udf_update_tag(epos.bh->b_data, 237 lenalloc + 238 sizeof(struct allocExtDesc)); 239 else 240 udf_update_tag(epos.bh->b_data, 241 sizeof(struct allocExtDesc)); 242 mark_buffer_dirty_inode(epos.bh, inode); 243 } 244 } 245 brelse(epos.bh); 246 epos.offset = sizeof(struct allocExtDesc); 247 epos.block = eloc; 248 epos.bh = udf_tread(sb, udf_get_lb_pblock(sb, eloc, 0)); 249 if (elen) 250 indirect_ext_len = (elen + sb->s_blocksize -1) >> 251 sb->s_blocksize_bits; 252 else 253 indirect_ext_len = 1; 254 } else { 255 extent_trunc(inode, &epos, eloc, etype, elen, 0); 256 epos.offset += adsize; 257 } 258 } 259 260 if (indirect_ext_len) { 261 if (!epos.bh) 262 BUG(); 263 udf_free_blocks(sb, inode, epos.block, 0, 264 indirect_ext_len); 265 } else { 266 if (!epos.bh) { 267 UDF_I_LENALLOC(inode) = lenalloc; 268 mark_inode_dirty(inode); 269 } else { 270 struct allocExtDesc *aed = 271 (struct allocExtDesc *)(epos.bh->b_data); 272 aed->lengthAllocDescs = cpu_to_le32(lenalloc); 273 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || 274 UDF_SB_UDFREV(sb) >= 0x0201) 275 udf_update_tag(epos.bh->b_data, 276 lenalloc + sizeof(struct allocExtDesc)); 277 else 278 udf_update_tag(epos.bh->b_data, 279 sizeof(struct allocExtDesc)); 280 mark_buffer_dirty_inode(epos.bh, inode); 281 } 282 } 283 } else if (inode->i_size) { 284 if (byte_offset) { 285 kernel_long_ad extent; 286 287 /* 288 * OK, there is not extent covering inode->i_size and 289 * no extent above inode->i_size => truncate is 290 * extending the file by 'offset' blocks. 291 */ 292 if ((!epos.bh && 293 epos.offset == udf_file_entry_alloc_offset(inode)) || 294 (epos.bh && epos.offset == sizeof(struct allocExtDesc))) { 295 /* File has no extents at all or has empty last 296 * indirect extent! Create a fake extent... */ 297 extent.extLocation.logicalBlockNum = 0; 298 extent.extLocation.partitionReferenceNum = 0; 299 extent.extLength = EXT_NOT_RECORDED_NOT_ALLOCATED; 300 } else { 301 epos.offset -= adsize; 302 etype = udf_next_aext(inode, &epos, 303 &extent.extLocation, 304 &extent.extLength, 0); 305 extent.extLength |= etype << 30; 306 } 307 udf_extend_file(inode, &epos, &extent, 308 offset + ((inode->i_size & (sb->s_blocksize - 1)) != 0)); 309 } 310 } 311 UDF_I_LENEXTENTS(inode) = inode->i_size; 312 313 brelse(epos.bh); 314 } 315