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 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 } 123 124 void 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 } 181 182 static 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 } 199 200 /* 201 * Truncate extents of inode to inode->i_size. This function can be used only 202 * for making file shorter. For making file longer, udf_extend_file() has to 203 * be used. 204 */ 205 void udf_truncate_extents(struct inode *inode) 206 { 207 struct extent_position epos; 208 struct kernel_lb_addr eloc, neloc = {}; 209 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc; 210 int8_t etype; 211 struct super_block *sb = inode->i_sb; 212 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset; 213 loff_t byte_offset; 214 int adsize; 215 struct udf_inode_info *iinfo = UDF_I(inode); 216 217 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 218 adsize = sizeof(struct short_ad); 219 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG) 220 adsize = sizeof(struct long_ad); 221 else 222 BUG(); 223 224 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset); 225 byte_offset = (offset << sb->s_blocksize_bits) + 226 (inode->i_size & (sb->s_blocksize - 1)); 227 if (etype == -1) { 228 /* We should extend the file? */ 229 WARN_ON(byte_offset); 230 return; 231 } 232 epos.offset -= adsize; 233 extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset); 234 epos.offset += adsize; 235 if (byte_offset) 236 lenalloc = epos.offset; 237 else 238 lenalloc = epos.offset - adsize; 239 240 if (!epos.bh) 241 lenalloc -= udf_file_entry_alloc_offset(inode); 242 else 243 lenalloc -= sizeof(struct allocExtDesc); 244 245 while ((etype = udf_current_aext(inode, &epos, &eloc, 246 &elen, 0)) != -1) { 247 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) { 248 udf_write_aext(inode, &epos, &neloc, nelen, 0); 249 if (indirect_ext_len) { 250 /* We managed to free all extents in the 251 * indirect extent - free it too */ 252 BUG_ON(!epos.bh); 253 udf_free_blocks(sb, inode, &epos.block, 254 0, indirect_ext_len); 255 } else if (!epos.bh) { 256 iinfo->i_lenAlloc = lenalloc; 257 mark_inode_dirty(inode); 258 } else 259 udf_update_alloc_ext_desc(inode, 260 &epos, lenalloc); 261 brelse(epos.bh); 262 epos.offset = sizeof(struct allocExtDesc); 263 epos.block = eloc; 264 epos.bh = udf_tread(sb, 265 udf_get_lb_pblock(sb, &eloc, 0)); 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, inode, &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 } 290