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/udf_fs.h> 26 #include <linux/buffer_head.h> 27 28 #include "udf_i.h" 29 #include "udf_sb.h" 30 31 static void extent_trunc(struct inode * inode, struct extent_position *epos, 32 kernel_lb_addr eloc, int8_t etype, uint32_t elen, uint32_t nelen) 33 { 34 kernel_lb_addr neloc = { 0, 0 }; 35 int last_block = (elen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits; 36 int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits; 37 38 if (nelen) 39 { 40 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) 41 { 42 udf_free_blocks(inode->i_sb, inode, eloc, 0, last_block); 43 etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30); 44 } 45 else 46 neloc = eloc; 47 nelen = (etype << 30) | nelen; 48 } 49 50 if (elen != nelen) 51 { 52 udf_write_aext(inode, epos, neloc, nelen, 0); 53 if (last_block - first_block > 0) 54 { 55 if (etype == (EXT_RECORDED_ALLOCATED >> 30)) 56 mark_inode_dirty(inode); 57 58 if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30)) 59 udf_free_blocks(inode->i_sb, inode, eloc, first_block, last_block - first_block); 60 } 61 } 62 } 63 64 void udf_discard_prealloc(struct inode * inode) 65 { 66 struct extent_position epos = { NULL, 0, {0, 0}}; 67 kernel_lb_addr eloc; 68 uint32_t elen, nelen; 69 uint64_t lbcount = 0; 70 int8_t etype = -1, netype; 71 int adsize; 72 73 if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB || 74 inode->i_size == UDF_I_LENEXTENTS(inode)) 75 return; 76 77 if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT) 78 adsize = sizeof(short_ad); 79 else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG) 80 adsize = sizeof(long_ad); 81 else 82 adsize = 0; 83 84 epos.block = UDF_I_LOCATION(inode); 85 86 /* Find the last extent in the file */ 87 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) 88 { 89 etype = netype; 90 lbcount += elen; 91 if (lbcount > inode->i_size && lbcount - elen < inode->i_size) 92 { 93 WARN_ON(lbcount - inode->i_size >= inode->i_sb->s_blocksize); 94 nelen = elen - (lbcount - inode->i_size); 95 epos.offset -= adsize; 96 extent_trunc(inode, &epos, eloc, etype, elen, nelen); 97 epos.offset += adsize; 98 lbcount = inode->i_size; 99 } 100 } 101 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { 102 epos.offset -= adsize; 103 lbcount -= elen; 104 extent_trunc(inode, &epos, eloc, etype, elen, 0); 105 if (!epos.bh) 106 { 107 UDF_I_LENALLOC(inode) = epos.offset - udf_file_entry_alloc_offset(inode); 108 mark_inode_dirty(inode); 109 } 110 else 111 { 112 struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data); 113 aed->lengthAllocDescs = cpu_to_le32(epos.offset - sizeof(struct allocExtDesc)); 114 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201) 115 udf_update_tag(epos.bh->b_data, epos.offset); 116 else 117 udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc)); 118 mark_buffer_dirty_inode(epos.bh, inode); 119 } 120 } 121 UDF_I_LENEXTENTS(inode) = lbcount; 122 123 WARN_ON(lbcount != inode->i_size); 124 brelse(epos.bh); 125 } 126 127 void udf_truncate_extents(struct inode * inode) 128 { 129 struct extent_position epos; 130 kernel_lb_addr eloc, neloc = { 0, 0 }; 131 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc; 132 int8_t etype; 133 struct super_block *sb = inode->i_sb; 134 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset; 135 loff_t byte_offset; 136 int adsize; 137 138 if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT) 139 adsize = sizeof(short_ad); 140 else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG) 141 adsize = sizeof(long_ad); 142 else 143 BUG(); 144 145 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset); 146 byte_offset = (offset << sb->s_blocksize_bits) + (inode->i_size & (sb->s_blocksize-1)); 147 if (etype != -1) 148 { 149 epos.offset -= adsize; 150 extent_trunc(inode, &epos, eloc, etype, elen, byte_offset); 151 epos.offset += adsize; 152 if (byte_offset) 153 lenalloc = epos.offset; 154 else 155 lenalloc = epos.offset - adsize; 156 157 if (!epos.bh) 158 lenalloc -= udf_file_entry_alloc_offset(inode); 159 else 160 lenalloc -= sizeof(struct allocExtDesc); 161 162 while ((etype = udf_current_aext(inode, &epos, &eloc, &elen, 0)) != -1) 163 { 164 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) 165 { 166 udf_write_aext(inode, &epos, neloc, nelen, 0); 167 if (indirect_ext_len) 168 { 169 /* We managed to free all extents in the 170 * indirect extent - free it too */ 171 if (!epos.bh) 172 BUG(); 173 udf_free_blocks(sb, inode, epos.block, 0, indirect_ext_len); 174 } 175 else 176 { 177 if (!epos.bh) 178 { 179 UDF_I_LENALLOC(inode) = lenalloc; 180 mark_inode_dirty(inode); 181 } 182 else 183 { 184 struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data); 185 aed->lengthAllocDescs = cpu_to_le32(lenalloc); 186 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(sb) >= 0x0201) 187 udf_update_tag(epos.bh->b_data, lenalloc + 188 sizeof(struct allocExtDesc)); 189 else 190 udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc)); 191 mark_buffer_dirty_inode(epos.bh, inode); 192 } 193 } 194 brelse(epos.bh); 195 epos.offset = sizeof(struct allocExtDesc); 196 epos.block = eloc; 197 epos.bh = udf_tread(sb, udf_get_lb_pblock(sb, eloc, 0)); 198 if (elen) 199 indirect_ext_len = (elen + 200 sb->s_blocksize - 1) >> 201 sb->s_blocksize_bits; 202 else 203 indirect_ext_len = 1; 204 } 205 else 206 { 207 extent_trunc(inode, &epos, eloc, etype, elen, 0); 208 epos.offset += adsize; 209 } 210 } 211 212 if (indirect_ext_len) 213 { 214 if (!epos.bh) 215 BUG(); 216 udf_free_blocks(sb, inode, epos.block, 0, indirect_ext_len); 217 } 218 else 219 { 220 if (!epos.bh) 221 { 222 UDF_I_LENALLOC(inode) = lenalloc; 223 mark_inode_dirty(inode); 224 } 225 else 226 { 227 struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data); 228 aed->lengthAllocDescs = cpu_to_le32(lenalloc); 229 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(sb) >= 0x0201) 230 udf_update_tag(epos.bh->b_data, lenalloc + 231 sizeof(struct allocExtDesc)); 232 else 233 udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc)); 234 mark_buffer_dirty_inode(epos.bh, inode); 235 } 236 } 237 } 238 else if (inode->i_size) 239 { 240 if (byte_offset) 241 { 242 kernel_long_ad extent; 243 244 /* 245 * OK, there is not extent covering inode->i_size and 246 * no extent above inode->i_size => truncate is 247 * extending the file by 'offset' blocks. 248 */ 249 if ((!epos.bh && epos.offset == udf_file_entry_alloc_offset(inode)) || 250 (epos.bh && epos.offset == sizeof(struct allocExtDesc))) { 251 /* File has no extents at all or has empty last 252 * indirect extent! Create a fake extent... */ 253 extent.extLocation.logicalBlockNum = 0; 254 extent.extLocation.partitionReferenceNum = 0; 255 extent.extLength = EXT_NOT_RECORDED_NOT_ALLOCATED; 256 } 257 else { 258 epos.offset -= adsize; 259 etype = udf_next_aext(inode, &epos, 260 &extent.extLocation, &extent.extLength, 0); 261 extent.extLength |= etype << 30; 262 } 263 udf_extend_file(inode, &epos, &extent, offset+((inode->i_size & (sb->s_blocksize-1)) != 0)); 264 } 265 } 266 UDF_I_LENEXTENTS(inode) = inode->i_size; 267 268 brelse(epos.bh); 269 } 270