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 31static void extent_trunc(struct inode * inode, struct extent_position *epos, 32 kernel_lb_addr eloc, int8_t etype, uint32_t elen, 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, epos, neloc, nelen, 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/* 65 * Truncate the last extent to match i_size. This function assumes 66 * that preallocation extent is already truncated. 67 */ 68void udf_truncate_tail_extent(struct inode *inode) 69{ 70 struct extent_position epos = { NULL, 0, {0, 0}}; 71 kernel_lb_addr eloc; 72 uint32_t elen, nelen; 73 uint64_t lbcount = 0; 74 int8_t etype = -1, netype; 75 int adsize; 76 77 if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB || 78 inode->i_size == UDF_I_LENEXTENTS(inode)) 79 return; 80 /* Are we going to delete the file anyway? */ 81 if (inode->i_nlink == 0) 82 return; 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 BUG(); 90 91 /* Find the last extent in the file */ 92 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) 93 { 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 124void 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) = epos.offset - udf_file_entry_alloc_offset(inode); 157 mark_inode_dirty(inode); 158 } else { 159 struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data); 160 aed->lengthAllocDescs = cpu_to_le32(epos.offset - sizeof(struct allocExtDesc)); 161 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201) 162 udf_update_tag(epos.bh->b_data, epos.offset); 163 else 164 udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc)); 165 mark_buffer_dirty_inode(epos.bh, inode); 166 } 167 } 168 /* This inode entry is in-memory only and thus we don't have to mark 169 * the inode dirty */ 170 UDF_I_LENEXTENTS(inode) = lbcount; 171 brelse(epos.bh); 172} 173 174void udf_truncate_extents(struct inode * inode) 175{ 176 struct extent_position epos; 177 kernel_lb_addr eloc, neloc = { 0, 0 }; 178 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc; 179 int8_t etype; 180 struct super_block *sb = inode->i_sb; 181 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset; 182 loff_t byte_offset; 183 int adsize; 184 185 if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT) 186 adsize = sizeof(short_ad); 187 else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG) 188 adsize = sizeof(long_ad); 189 else 190 BUG(); 191 192 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset); 193 byte_offset = (offset << sb->s_blocksize_bits) + (inode->i_size & (sb->s_blocksize-1)); 194 if (etype != -1) 195 { 196 epos.offset -= adsize; 197 extent_trunc(inode, &epos, eloc, etype, elen, byte_offset); 198 epos.offset += adsize; 199 if (byte_offset) 200 lenalloc = epos.offset; 201 else 202 lenalloc = epos.offset - adsize; 203 204 if (!epos.bh) 205 lenalloc -= udf_file_entry_alloc_offset(inode); 206 else 207 lenalloc -= sizeof(struct allocExtDesc); 208 209 while ((etype = udf_current_aext(inode, &epos, &eloc, &elen, 0)) != -1) 210 { 211 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) 212 { 213 udf_write_aext(inode, &epos, neloc, nelen, 0); 214 if (indirect_ext_len) 215 { 216 /* We managed to free all extents in the 217 * indirect extent - free it too */ 218 if (!epos.bh) 219 BUG(); 220 udf_free_blocks(sb, inode, epos.block, 0, indirect_ext_len); 221 } 222 else 223 { 224 if (!epos.bh) 225 { 226 UDF_I_LENALLOC(inode) = lenalloc; 227 mark_inode_dirty(inode); 228 } 229 else 230 { 231 struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data); 232 aed->lengthAllocDescs = cpu_to_le32(lenalloc); 233 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(sb) >= 0x0201) 234 udf_update_tag(epos.bh->b_data, lenalloc + 235 sizeof(struct allocExtDesc)); 236 else 237 udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc)); 238 mark_buffer_dirty_inode(epos.bh, inode); 239 } 240 } 241 brelse(epos.bh); 242 epos.offset = sizeof(struct allocExtDesc); 243 epos.block = eloc; 244 epos.bh = udf_tread(sb, udf_get_lb_pblock(sb, eloc, 0)); 245 if (elen) 246 indirect_ext_len = (elen + 247 sb->s_blocksize - 1) >> 248 sb->s_blocksize_bits; 249 else 250 indirect_ext_len = 1; 251 } 252 else 253 { 254 extent_trunc(inode, &epos, eloc, etype, elen, 0); 255 epos.offset += adsize; 256 } 257 } 258 259 if (indirect_ext_len) 260 { 261 if (!epos.bh) 262 BUG(); 263 udf_free_blocks(sb, inode, epos.block, 0, indirect_ext_len); 264 } 265 else 266 { 267 if (!epos.bh) 268 { 269 UDF_I_LENALLOC(inode) = lenalloc; 270 mark_inode_dirty(inode); 271 } 272 else 273 { 274 struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data); 275 aed->lengthAllocDescs = cpu_to_le32(lenalloc); 276 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(sb) >= 0x0201) 277 udf_update_tag(epos.bh->b_data, lenalloc + 278 sizeof(struct allocExtDesc)); 279 else 280 udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc)); 281 mark_buffer_dirty_inode(epos.bh, inode); 282 } 283 } 284 } 285 else if (inode->i_size) 286 { 287 if (byte_offset) 288 { 289 kernel_long_ad extent; 290 291 /* 292 * OK, there is not extent covering inode->i_size and 293 * no extent above inode->i_size => truncate is 294 * extending the file by 'offset' blocks. 295 */ 296 if ((!epos.bh && epos.offset == udf_file_entry_alloc_offset(inode)) || 297 (epos.bh && epos.offset == sizeof(struct allocExtDesc))) { 298 /* File has no extents at all or has empty last 299 * indirect extent! Create a fake extent... */ 300 extent.extLocation.logicalBlockNum = 0; 301 extent.extLocation.partitionReferenceNum = 0; 302 extent.extLength = EXT_NOT_RECORDED_NOT_ALLOCATED; 303 } 304 else { 305 epos.offset -= adsize; 306 etype = udf_next_aext(inode, &epos, 307 &extent.extLocation, &extent.extLength, 0); 308 extent.extLength |= etype << 30; 309 } 310 udf_extend_file(inode, &epos, &extent, offset+((inode->i_size & (sb->s_blocksize-1)) != 0)); 311 } 312 } 313 UDF_I_LENEXTENTS(inode) = inode->i_size; 314 315 brelse(epos.bh); 316} 317