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 26 #include "udf_i.h" 27 #include "udf_sb.h" 28 29 static void extent_trunc(struct inode *inode, struct extent_position *epos, 30 struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen, 31 uint32_t nelen) 32 { 33 struct kernel_lb_addr neloc = {}; 34 int last_block = (elen + inode->i_sb->s_blocksize - 1) >> 35 inode->i_sb->s_blocksize_bits; 36 int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> 37 inode->i_sb->s_blocksize_bits; 38 39 if (nelen) { 40 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { 41 udf_free_blocks(inode->i_sb, inode, eloc, 0, 42 last_block); 43 etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30); 44 } else 45 neloc = *eloc; 46 nelen = (etype << 30) | nelen; 47 } 48 49 if (elen != nelen) { 50 udf_write_aext(inode, epos, &neloc, nelen, 0); 51 if (last_block > first_block) { 52 if (etype == (EXT_RECORDED_ALLOCATED >> 30)) 53 mark_inode_dirty(inode); 54 55 if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30)) 56 udf_free_blocks(inode->i_sb, inode, eloc, 57 first_block, 58 last_block - first_block); 59 } 60 } 61 } 62 63 /* 64 * Truncate the last extent to match i_size. This function assumes 65 * that preallocation extent is already truncated. 66 */ 67 void udf_truncate_tail_extent(struct inode *inode) 68 { 69 struct extent_position epos = {}; 70 struct kernel_lb_addr eloc; 71 uint32_t elen, nelen; 72 uint64_t lbcount = 0; 73 int8_t etype = -1, netype; 74 int adsize; 75 struct udf_inode_info *iinfo = UDF_I(inode); 76 77 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB || 78 inode->i_size == iinfo->i_lenExtents) 79 return; 80 /* Are we going to delete the file anyway? */ 81 if (inode->i_nlink == 0) 82 return; 83 84 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 85 adsize = sizeof(struct short_ad); 86 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 87 adsize = sizeof(struct 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 etype = netype; 94 lbcount += elen; 95 if (lbcount > inode->i_size) { 96 if (lbcount - inode->i_size >= inode->i_sb->s_blocksize) 97 udf_warn(inode->i_sb, 98 "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n", 99 (unsigned)inode->i_ino, 100 (long long)inode->i_size, 101 (long long)lbcount, 102 (unsigned)eloc.logicalBlockNum, 103 (unsigned)elen); 104 nelen = elen - (lbcount - inode->i_size); 105 epos.offset -= adsize; 106 extent_trunc(inode, &epos, &eloc, etype, elen, nelen); 107 epos.offset += adsize; 108 if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1) 109 udf_err(inode->i_sb, 110 "Extent after EOF in inode %u\n", 111 (unsigned)inode->i_ino); 112 break; 113 } 114 } 115 /* This inode entry is in-memory only and thus we don't have to mark 116 * the inode dirty */ 117 iinfo->i_lenExtents = inode->i_size; 118 brelse(epos.bh); 119 } 120 121 void udf_discard_prealloc(struct inode *inode) 122 { 123 struct extent_position epos = { NULL, 0, {0, 0} }; 124 struct kernel_lb_addr eloc; 125 uint32_t elen; 126 uint64_t lbcount = 0; 127 int8_t etype = -1, netype; 128 int adsize; 129 struct udf_inode_info *iinfo = UDF_I(inode); 130 131 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB || 132 inode->i_size == iinfo->i_lenExtents) 133 return; 134 135 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 136 adsize = sizeof(struct short_ad); 137 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 138 adsize = sizeof(struct long_ad); 139 else 140 adsize = 0; 141 142 epos.block = iinfo->i_location; 143 144 /* Find the last extent in the file */ 145 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) { 146 etype = netype; 147 lbcount += elen; 148 } 149 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { 150 epos.offset -= adsize; 151 lbcount -= elen; 152 extent_trunc(inode, &epos, &eloc, etype, elen, 0); 153 if (!epos.bh) { 154 iinfo->i_lenAlloc = 155 epos.offset - 156 udf_file_entry_alloc_offset(inode); 157 mark_inode_dirty(inode); 158 } else { 159 struct allocExtDesc *aed = 160 (struct allocExtDesc *)(epos.bh->b_data); 161 aed->lengthAllocDescs = 162 cpu_to_le32(epos.offset - 163 sizeof(struct allocExtDesc)); 164 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || 165 UDF_SB(inode->i_sb)->s_udfrev >= 0x0201) 166 udf_update_tag(epos.bh->b_data, epos.offset); 167 else 168 udf_update_tag(epos.bh->b_data, 169 sizeof(struct allocExtDesc)); 170 mark_buffer_dirty_inode(epos.bh, inode); 171 } 172 } 173 /* This inode entry is in-memory only and thus we don't have to mark 174 * the inode dirty */ 175 iinfo->i_lenExtents = lbcount; 176 brelse(epos.bh); 177 } 178 179 static void udf_update_alloc_ext_desc(struct inode *inode, 180 struct extent_position *epos, 181 u32 lenalloc) 182 { 183 struct super_block *sb = inode->i_sb; 184 struct udf_sb_info *sbi = UDF_SB(sb); 185 186 struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data); 187 int len = sizeof(struct allocExtDesc); 188 189 aed->lengthAllocDescs = cpu_to_le32(lenalloc); 190 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201) 191 len += lenalloc; 192 193 udf_update_tag(epos->bh->b_data, len); 194 mark_buffer_dirty_inode(epos->bh, inode); 195 } 196 197 /* 198 * Truncate extents of inode to inode->i_size. This function can be used only 199 * for making file shorter. For making file longer, udf_extend_file() has to 200 * be used. 201 */ 202 int udf_truncate_extents(struct inode *inode) 203 { 204 struct extent_position epos; 205 struct kernel_lb_addr eloc, neloc = {}; 206 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc; 207 int8_t etype; 208 struct super_block *sb = inode->i_sb; 209 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset; 210 loff_t byte_offset; 211 int adsize; 212 struct udf_inode_info *iinfo = UDF_I(inode); 213 214 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 215 adsize = sizeof(struct short_ad); 216 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 217 adsize = sizeof(struct long_ad); 218 else 219 BUG(); 220 221 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset); 222 byte_offset = (offset << sb->s_blocksize_bits) + 223 (inode->i_size & (sb->s_blocksize - 1)); 224 if (etype == -1) { 225 /* We should extend the file? */ 226 WARN_ON(byte_offset); 227 return 0; 228 } 229 epos.offset -= adsize; 230 extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset); 231 epos.offset += adsize; 232 if (byte_offset) 233 lenalloc = epos.offset; 234 else 235 lenalloc = epos.offset - adsize; 236 237 if (!epos.bh) 238 lenalloc -= udf_file_entry_alloc_offset(inode); 239 else 240 lenalloc -= sizeof(struct allocExtDesc); 241 242 while ((etype = udf_current_aext(inode, &epos, &eloc, 243 &elen, 0)) != -1) { 244 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) { 245 udf_write_aext(inode, &epos, &neloc, nelen, 0); 246 if (indirect_ext_len) { 247 /* We managed to free all extents in the 248 * indirect extent - free it too */ 249 BUG_ON(!epos.bh); 250 udf_free_blocks(sb, NULL, &epos.block, 251 0, indirect_ext_len); 252 } else if (!epos.bh) { 253 iinfo->i_lenAlloc = lenalloc; 254 mark_inode_dirty(inode); 255 } else 256 udf_update_alloc_ext_desc(inode, 257 &epos, lenalloc); 258 brelse(epos.bh); 259 epos.offset = sizeof(struct allocExtDesc); 260 epos.block = eloc; 261 epos.bh = udf_tread(sb, 262 udf_get_lb_pblock(sb, &eloc, 0)); 263 /* Error reading indirect block? */ 264 if (!epos.bh) 265 return -EIO; 266 if (elen) 267 indirect_ext_len = 268 (elen + sb->s_blocksize - 1) >> 269 sb->s_blocksize_bits; 270 else 271 indirect_ext_len = 1; 272 } else { 273 extent_trunc(inode, &epos, &eloc, etype, elen, 0); 274 epos.offset += adsize; 275 } 276 } 277 278 if (indirect_ext_len) { 279 BUG_ON(!epos.bh); 280 udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len); 281 } else if (!epos.bh) { 282 iinfo->i_lenAlloc = lenalloc; 283 mark_inode_dirty(inode); 284 } else 285 udf_update_alloc_ext_desc(inode, &epos, lenalloc); 286 iinfo->i_lenExtents = inode->i_size; 287 288 brelse(epos.bh); 289 return 0; 290 } 291