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 30 static 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 */ 68 void 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 udf_warn(inode->i_sb, 99 "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n", 100 (unsigned)inode->i_ino, 101 (long long)inode->i_size, 102 (long long)lbcount, 103 (unsigned)eloc.logicalBlockNum, 104 (unsigned)elen); 105 nelen = elen - (lbcount - inode->i_size); 106 epos.offset -= adsize; 107 extent_trunc(inode, &epos, &eloc, etype, elen, nelen); 108 epos.offset += adsize; 109 if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1) 110 udf_err(inode->i_sb, 111 "Extent after EOF in inode %u\n", 112 (unsigned)inode->i_ino); 113 break; 114 } 115 } 116 /* This inode entry is in-memory only and thus we don't have to mark 117 * the inode dirty */ 118 iinfo->i_lenExtents = inode->i_size; 119 brelse(epos.bh); 120 } 121 122 void udf_discard_prealloc(struct inode *inode) 123 { 124 struct extent_position epos = { NULL, 0, {0, 0} }; 125 struct kernel_lb_addr eloc; 126 uint32_t elen; 127 uint64_t lbcount = 0; 128 int8_t etype = -1, netype; 129 int adsize; 130 struct udf_inode_info *iinfo = UDF_I(inode); 131 132 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB || 133 inode->i_size == iinfo->i_lenExtents) 134 return; 135 136 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 137 adsize = sizeof(struct short_ad); 138 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 139 adsize = sizeof(struct long_ad); 140 else 141 adsize = 0; 142 143 epos.block = iinfo->i_location; 144 145 /* Find the last extent in the file */ 146 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) { 147 etype = netype; 148 lbcount += elen; 149 } 150 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { 151 epos.offset -= adsize; 152 lbcount -= elen; 153 extent_trunc(inode, &epos, &eloc, etype, elen, 0); 154 if (!epos.bh) { 155 iinfo->i_lenAlloc = 156 epos.offset - 157 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(inode->i_sb)->s_udfrev >= 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 iinfo->i_lenExtents = lbcount; 177 brelse(epos.bh); 178 } 179 180 static void udf_update_alloc_ext_desc(struct inode *inode, 181 struct extent_position *epos, 182 u32 lenalloc) 183 { 184 struct super_block *sb = inode->i_sb; 185 struct udf_sb_info *sbi = UDF_SB(sb); 186 187 struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data); 188 int len = sizeof(struct allocExtDesc); 189 190 aed->lengthAllocDescs = cpu_to_le32(lenalloc); 191 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201) 192 len += lenalloc; 193 194 udf_update_tag(epos->bh->b_data, len); 195 mark_buffer_dirty_inode(epos->bh, inode); 196 } 197 198 /* 199 * Truncate extents of inode to inode->i_size. This function can be used only 200 * for making file shorter. For making file longer, udf_extend_file() has to 201 * be used. 202 */ 203 void udf_truncate_extents(struct inode *inode) 204 { 205 struct extent_position epos; 206 struct kernel_lb_addr eloc, neloc = {}; 207 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc; 208 int8_t etype; 209 struct super_block *sb = inode->i_sb; 210 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset; 211 loff_t byte_offset; 212 int adsize; 213 struct udf_inode_info *iinfo = UDF_I(inode); 214 215 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 216 adsize = sizeof(struct short_ad); 217 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 218 adsize = sizeof(struct long_ad); 219 else 220 BUG(); 221 222 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset); 223 byte_offset = (offset << sb->s_blocksize_bits) + 224 (inode->i_size & (sb->s_blocksize - 1)); 225 if (etype == -1) { 226 /* We should extend the file? */ 227 WARN_ON(byte_offset); 228 return; 229 } 230 epos.offset -= adsize; 231 extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset); 232 epos.offset += adsize; 233 if (byte_offset) 234 lenalloc = epos.offset; 235 else 236 lenalloc = epos.offset - adsize; 237 238 if (!epos.bh) 239 lenalloc -= udf_file_entry_alloc_offset(inode); 240 else 241 lenalloc -= sizeof(struct allocExtDesc); 242 243 while ((etype = udf_current_aext(inode, &epos, &eloc, 244 &elen, 0)) != -1) { 245 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) { 246 udf_write_aext(inode, &epos, &neloc, nelen, 0); 247 if (indirect_ext_len) { 248 /* We managed to free all extents in the 249 * indirect extent - free it too */ 250 BUG_ON(!epos.bh); 251 udf_free_blocks(sb, NULL, &epos.block, 252 0, indirect_ext_len); 253 } else if (!epos.bh) { 254 iinfo->i_lenAlloc = lenalloc; 255 mark_inode_dirty(inode); 256 } else 257 udf_update_alloc_ext_desc(inode, 258 &epos, lenalloc); 259 brelse(epos.bh); 260 epos.offset = sizeof(struct allocExtDesc); 261 epos.block = eloc; 262 epos.bh = udf_tread(sb, 263 udf_get_lb_pblock(sb, &eloc, 0)); 264 if (elen) 265 indirect_ext_len = 266 (elen + sb->s_blocksize - 1) >> 267 sb->s_blocksize_bits; 268 else 269 indirect_ext_len = 1; 270 } else { 271 extent_trunc(inode, &epos, &eloc, etype, elen, 0); 272 epos.offset += adsize; 273 } 274 } 275 276 if (indirect_ext_len) { 277 BUG_ON(!epos.bh); 278 udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len); 279 } else if (!epos.bh) { 280 iinfo->i_lenAlloc = lenalloc; 281 mark_inode_dirty(inode); 282 } else 283 udf_update_alloc_ext_desc(inode, &epos, lenalloc); 284 iinfo->i_lenExtents = inode->i_size; 285 286 brelse(epos.bh); 287 } 288