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 = {}; 124 struct extent_position prev_epos = {}; 125 struct kernel_lb_addr eloc; 126 uint32_t elen; 127 uint64_t lbcount = 0; 128 int8_t etype = -1; 129 struct udf_inode_info *iinfo = UDF_I(inode); 130 int bsize = 1 << inode->i_blkbits; 131 132 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB || 133 ALIGN(inode->i_size, bsize) == ALIGN(iinfo->i_lenExtents, bsize)) 134 return; 135 136 epos.block = iinfo->i_location; 137 138 /* Find the last extent in the file */ 139 while (udf_next_aext(inode, &epos, &eloc, &elen, 0) != -1) { 140 brelse(prev_epos.bh); 141 prev_epos = epos; 142 if (prev_epos.bh) 143 get_bh(prev_epos.bh); 144 145 etype = udf_next_aext(inode, &epos, &eloc, &elen, 1); 146 lbcount += elen; 147 } 148 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { 149 lbcount -= elen; 150 udf_delete_aext(inode, prev_epos); 151 udf_free_blocks(inode->i_sb, inode, &eloc, 0, 152 DIV_ROUND_UP(elen, 1 << inode->i_blkbits)); 153 } 154 /* This inode entry is in-memory only and thus we don't have to mark 155 * the inode dirty */ 156 iinfo->i_lenExtents = lbcount; 157 brelse(epos.bh); 158 brelse(prev_epos.bh); 159 } 160 161 static void udf_update_alloc_ext_desc(struct inode *inode, 162 struct extent_position *epos, 163 u32 lenalloc) 164 { 165 struct super_block *sb = inode->i_sb; 166 struct udf_sb_info *sbi = UDF_SB(sb); 167 168 struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data); 169 int len = sizeof(struct allocExtDesc); 170 171 aed->lengthAllocDescs = cpu_to_le32(lenalloc); 172 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201) 173 len += lenalloc; 174 175 udf_update_tag(epos->bh->b_data, len); 176 mark_buffer_dirty_inode(epos->bh, inode); 177 } 178 179 /* 180 * Truncate extents of inode to inode->i_size. This function can be used only 181 * for making file shorter. For making file longer, udf_extend_file() has to 182 * be used. 183 */ 184 int udf_truncate_extents(struct inode *inode) 185 { 186 struct extent_position epos; 187 struct kernel_lb_addr eloc, neloc = {}; 188 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc; 189 int8_t etype; 190 struct super_block *sb = inode->i_sb; 191 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset; 192 loff_t byte_offset; 193 int adsize; 194 struct udf_inode_info *iinfo = UDF_I(inode); 195 196 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 197 adsize = sizeof(struct short_ad); 198 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 199 adsize = sizeof(struct long_ad); 200 else 201 BUG(); 202 203 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset); 204 byte_offset = (offset << sb->s_blocksize_bits) + 205 (inode->i_size & (sb->s_blocksize - 1)); 206 if (etype == -1) { 207 /* We should extend the file? */ 208 WARN_ON(byte_offset); 209 return 0; 210 } 211 epos.offset -= adsize; 212 extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset); 213 epos.offset += adsize; 214 if (byte_offset) 215 lenalloc = epos.offset; 216 else 217 lenalloc = epos.offset - adsize; 218 219 if (!epos.bh) 220 lenalloc -= udf_file_entry_alloc_offset(inode); 221 else 222 lenalloc -= sizeof(struct allocExtDesc); 223 224 while ((etype = udf_current_aext(inode, &epos, &eloc, 225 &elen, 0)) != -1) { 226 if (etype == (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) { 227 udf_write_aext(inode, &epos, &neloc, nelen, 0); 228 if (indirect_ext_len) { 229 /* We managed to free all extents in the 230 * indirect extent - free it too */ 231 BUG_ON(!epos.bh); 232 udf_free_blocks(sb, NULL, &epos.block, 233 0, indirect_ext_len); 234 } else if (!epos.bh) { 235 iinfo->i_lenAlloc = lenalloc; 236 mark_inode_dirty(inode); 237 } else 238 udf_update_alloc_ext_desc(inode, 239 &epos, lenalloc); 240 brelse(epos.bh); 241 epos.offset = sizeof(struct allocExtDesc); 242 epos.block = eloc; 243 epos.bh = sb_bread(sb, 244 udf_get_lb_pblock(sb, &eloc, 0)); 245 /* Error reading indirect block? */ 246 if (!epos.bh) 247 return -EIO; 248 if (elen) 249 indirect_ext_len = 250 (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 BUG_ON(!epos.bh); 262 udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len); 263 } else if (!epos.bh) { 264 iinfo->i_lenAlloc = lenalloc; 265 mark_inode_dirty(inode); 266 } else 267 udf_update_alloc_ext_desc(inode, &epos, lenalloc); 268 iinfo->i_lenExtents = inode->i_size; 269 270 brelse(epos.bh); 271 return 0; 272 } 273