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/buffer_head.h> 26 27#include "udf_i.h" 28#include "udf_sb.h" 29 30static void extent_trunc(struct inode *inode, struct extent_position *epos, 31 struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen, 32 uint32_t nelen) 33{ 34 struct kernel_lb_addr neloc = {}; 35 int last_block = (elen + inode->i_sb->s_blocksize - 1) >> 36 inode->i_sb->s_blocksize_bits; 37 int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> 38 inode->i_sb->s_blocksize_bits; 39 40 if (nelen) { 41 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { 42 udf_free_blocks(inode->i_sb, inode, eloc, 0, 43 last_block); 44 etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30); 45 } else 46 neloc = *eloc; 47 nelen = (etype << 30) | nelen; 48 } 49 50 if (elen != nelen) { 51 udf_write_aext(inode, epos, &neloc, nelen, 0); 52 if (last_block - first_block > 0) { 53 if (etype == (EXT_RECORDED_ALLOCATED >> 30)) 54 mark_inode_dirty(inode); 55 56 if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30)) 57 udf_free_blocks(inode->i_sb, inode, eloc, 58 first_block, 59 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 = {}; 71 struct kernel_lb_addr eloc; 72 uint32_t elen, nelen; 73 uint64_t lbcount = 0; 74 int8_t etype = -1, netype; 75 int adsize; 76 struct udf_inode_info *iinfo = UDF_I(inode); 77 78 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB || 79 inode->i_size == iinfo->i_lenExtents) 80 return; 81 /* Are we going to delete the file anyway? */ 82 if (inode->i_nlink == 0) 83 return; 84 85 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 86 adsize = sizeof(struct short_ad); 87 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 88 adsize = sizeof(struct 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 iinfo->i_lenExtents = 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 struct kernel_lb_addr eloc; 128 uint32_t elen; 129 uint64_t lbcount = 0; 130 int8_t etype = -1, netype; 131 int adsize; 132 struct udf_inode_info *iinfo = UDF_I(inode); 133 134 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB || 135 inode->i_size == iinfo->i_lenExtents) 136 return; 137 138 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 139 adsize = sizeof(struct short_ad); 140 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 141 adsize = sizeof(struct long_ad); 142 else 143 adsize = 0; 144 145 epos.block = iinfo->i_location; 146 147 /* Find the last extent in the file */ 148 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) { 149 etype = netype; 150 lbcount += elen; 151 } 152 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { 153 epos.offset -= adsize; 154 lbcount -= elen; 155 extent_trunc(inode, &epos, &eloc, etype, elen, 0); 156 if (!epos.bh) { 157 iinfo->i_lenAlloc = 158 epos.offset - 159 udf_file_entry_alloc_offset(inode); 160 mark_inode_dirty(inode); 161 } else { 162 struct allocExtDesc *aed = 163 (struct allocExtDesc *)(epos.bh->b_data); 164 aed->lengthAllocDescs = 165 cpu_to_le32(epos.offset - 166 sizeof(struct allocExtDesc)); 167 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || 168 UDF_SB(inode->i_sb)->s_udfrev >= 0x0201) 169 udf_update_tag(epos.bh->b_data, epos.offset); 170 else 171 udf_update_tag(epos.bh->b_data, 172 sizeof(struct allocExtDesc)); 173 mark_buffer_dirty_inode(epos.bh, inode); 174 } 175 } 176 /* This inode entry is in-memory only and thus we don't have to mark 177 * the inode dirty */ 178 iinfo->i_lenExtents = lbcount; 179 brelse(epos.bh); 180} 181 182static void udf_update_alloc_ext_desc(struct inode *inode, 183 struct extent_position *epos, 184 u32 lenalloc) 185{ 186 struct super_block *sb = inode->i_sb; 187 struct udf_sb_info *sbi = UDF_SB(sb); 188 189 struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data); 190 int len = sizeof(struct allocExtDesc); 191 192 aed->lengthAllocDescs = cpu_to_le32(lenalloc); 193 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201) 194 len += lenalloc; 195 196 udf_update_tag(epos->bh->b_data, len); 197 mark_buffer_dirty_inode(epos->bh, inode); 198} 199 200void udf_truncate_extents(struct inode *inode) 201{ 202 struct extent_position epos; 203 struct kernel_lb_addr eloc, neloc = {}; 204 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc; 205 int8_t etype; 206 struct super_block *sb = inode->i_sb; 207 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset; 208 loff_t byte_offset; 209 int adsize; 210 struct udf_inode_info *iinfo = UDF_I(inode); 211 212 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 213 adsize = sizeof(struct short_ad); 214 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 215 adsize = sizeof(struct long_ad); 216 else 217 BUG(); 218 219 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset); 220 byte_offset = (offset << sb->s_blocksize_bits) + 221 (inode->i_size & (sb->s_blocksize - 1)); 222 if (etype != -1) { 223 epos.offset -= adsize; 224 extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset); 225 epos.offset += adsize; 226 if (byte_offset) 227 lenalloc = epos.offset; 228 else 229 lenalloc = epos.offset - adsize; 230 231 if (!epos.bh) 232 lenalloc -= udf_file_entry_alloc_offset(inode); 233 else 234 lenalloc -= sizeof(struct allocExtDesc); 235 236 while ((etype = udf_current_aext(inode, &epos, &eloc, 237 &elen, 0)) != -1) { 238 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) { 239 udf_write_aext(inode, &epos, &neloc, nelen, 0); 240 if (indirect_ext_len) { 241 /* We managed to free all extents in the 242 * indirect extent - free it too */ 243 BUG_ON(!epos.bh); 244 udf_free_blocks(sb, inode, &epos.block, 245 0, indirect_ext_len); 246 } else if (!epos.bh) { 247 iinfo->i_lenAlloc = lenalloc; 248 mark_inode_dirty(inode); 249 } else 250 udf_update_alloc_ext_desc(inode, 251 &epos, lenalloc); 252 brelse(epos.bh); 253 epos.offset = sizeof(struct allocExtDesc); 254 epos.block = eloc; 255 epos.bh = udf_tread(sb, 256 udf_get_lb_pblock(sb, &eloc, 0)); 257 if (elen) 258 indirect_ext_len = 259 (elen + sb->s_blocksize - 1) >> 260 sb->s_blocksize_bits; 261 else 262 indirect_ext_len = 1; 263 } else { 264 extent_trunc(inode, &epos, &eloc, etype, 265 elen, 0); 266 epos.offset += adsize; 267 } 268 } 269 270 if (indirect_ext_len) { 271 BUG_ON(!epos.bh); 272 udf_free_blocks(sb, inode, &epos.block, 0, 273 indirect_ext_len); 274 } else if (!epos.bh) { 275 iinfo->i_lenAlloc = lenalloc; 276 mark_inode_dirty(inode); 277 } else 278 udf_update_alloc_ext_desc(inode, &epos, lenalloc); 279 } else if (inode->i_size) { 280 if (byte_offset) { 281 struct kernel_long_ad extent; 282 283 /* 284 * OK, there is not extent covering inode->i_size and 285 * no extent above inode->i_size => truncate is 286 * extending the file by 'offset' blocks. 287 */ 288 if ((!epos.bh && 289 epos.offset == 290 udf_file_entry_alloc_offset(inode)) || 291 (epos.bh && epos.offset == 292 sizeof(struct allocExtDesc))) { 293 /* File has no extents at all or has empty last 294 * indirect extent! Create a fake extent... */ 295 extent.extLocation.logicalBlockNum = 0; 296 extent.extLocation.partitionReferenceNum = 0; 297 extent.extLength = 298 EXT_NOT_RECORDED_NOT_ALLOCATED; 299 } else { 300 epos.offset -= adsize; 301 etype = udf_next_aext(inode, &epos, 302 &extent.extLocation, 303 &extent.extLength, 0); 304 extent.extLength |= etype << 30; 305 } 306 udf_extend_file(inode, &epos, &extent, 307 offset + 308 ((inode->i_size & 309 (sb->s_blocksize - 1)) != 0)); 310 } 311 } 312 iinfo->i_lenExtents = inode->i_size; 313 314 brelse(epos.bh); 315} 316