1 /* 2 * bmap.c --- logical to physical block mapping 3 * 4 * Copyright (C) 1997 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the GNU Library 8 * General Public License, version 2. 9 * %End-Header% 10 */ 11 12 #include <stdio.h> 13 #include <string.h> 14 #if HAVE_UNISTD_H 15 #include <unistd.h> 16 #endif 17 #include <errno.h> 18 19 #include "ext2_fs.h" 20 #include "ext2fs.h" 21 22 #if defined(__GNUC__) && !defined(NO_INLINE_FUNCS) 23 #define _BMAP_INLINE_ __inline__ 24 #else 25 #define _BMAP_INLINE_ 26 #endif 27 28 extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, 29 struct ext2_inode *inode, 30 char *block_buf, int bmap_flags, 31 blk_t block, blk_t *phys_blk); 32 33 #define inode_bmap(inode, nr) ((inode)->i_block[(nr)]) 34 35 static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags, 36 blk_t ind, char *block_buf, 37 int *blocks_alloc, 38 blk_t nr, blk_t *ret_blk) 39 { 40 errcode_t retval; 41 blk_t b; 42 43 if (!ind) { 44 if (flags & BMAP_SET) 45 return EXT2_ET_SET_BMAP_NO_IND; 46 *ret_blk = 0; 47 return 0; 48 } 49 retval = io_channel_read_blk(fs->io, ind, 1, block_buf); 50 if (retval) 51 return retval; 52 53 if (flags & BMAP_SET) { 54 b = *ret_blk; 55 #ifdef WORDS_BIGENDIAN 56 b = ext2fs_swab32(b); 57 #endif 58 ((blk_t *) block_buf)[nr] = b; 59 return io_channel_write_blk(fs->io, ind, 1, block_buf); 60 } 61 62 b = ((blk_t *) block_buf)[nr]; 63 64 #ifdef WORDS_BIGENDIAN 65 b = ext2fs_swab32(b); 66 #endif 67 68 if (!b && (flags & BMAP_ALLOC)) { 69 b = nr ? ((blk_t *) block_buf)[nr-1] : 0; 70 retval = ext2fs_alloc_block(fs, b, 71 block_buf + fs->blocksize, &b); 72 if (retval) 73 return retval; 74 75 #ifdef WORDS_BIGENDIAN 76 ((blk_t *) block_buf)[nr] = ext2fs_swab32(b); 77 #else 78 ((blk_t *) block_buf)[nr] = b; 79 #endif 80 81 retval = io_channel_write_blk(fs->io, ind, 1, block_buf); 82 if (retval) 83 return retval; 84 85 (*blocks_alloc)++; 86 } 87 88 *ret_blk = b; 89 return 0; 90 } 91 92 static _BMAP_INLINE_ errcode_t block_dind_bmap(ext2_filsys fs, int flags, 93 blk_t dind, char *block_buf, 94 int *blocks_alloc, 95 blk_t nr, blk_t *ret_blk) 96 { 97 blk_t b; 98 errcode_t retval; 99 blk_t addr_per_block; 100 101 addr_per_block = (blk_t) fs->blocksize >> 2; 102 103 retval = block_ind_bmap(fs, flags & ~BMAP_SET, dind, block_buf, 104 blocks_alloc, nr / addr_per_block, &b); 105 if (retval) 106 return retval; 107 retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc, 108 nr % addr_per_block, ret_blk); 109 return retval; 110 } 111 112 static _BMAP_INLINE_ errcode_t block_tind_bmap(ext2_filsys fs, int flags, 113 blk_t tind, char *block_buf, 114 int *blocks_alloc, 115 blk_t nr, blk_t *ret_blk) 116 { 117 blk_t b; 118 errcode_t retval; 119 blk_t addr_per_block; 120 121 addr_per_block = (blk_t) fs->blocksize >> 2; 122 123 retval = block_dind_bmap(fs, flags & ~BMAP_SET, tind, block_buf, 124 blocks_alloc, nr / addr_per_block, &b); 125 if (retval) 126 return retval; 127 retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc, 128 nr % addr_per_block, ret_blk); 129 return retval; 130 } 131 132 errcode_t ext2fs_bmap2(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode, 133 char *block_buf, int bmap_flags, blk64_t block, 134 int *ret_flags, blk64_t *phys_blk) 135 { 136 struct ext2_inode inode_buf; 137 ext2_extent_handle_t handle = 0; 138 blk_t addr_per_block; 139 blk_t b, blk32; 140 char *buf = 0; 141 errcode_t retval = 0; 142 int blocks_alloc = 0, inode_dirty = 0; 143 144 if (!(bmap_flags & BMAP_SET)) 145 *phys_blk = 0; 146 147 if (ret_flags) 148 *ret_flags = 0; 149 150 /* Read inode structure if necessary */ 151 if (!inode) { 152 retval = ext2fs_read_inode(fs, ino, &inode_buf); 153 if (retval) 154 return retval; 155 inode = &inode_buf; 156 } 157 addr_per_block = (blk_t) fs->blocksize >> 2; 158 159 if (inode->i_flags & EXT4_EXTENTS_FL) { 160 struct ext2fs_extent extent; 161 unsigned int offset; 162 163 retval = ext2fs_extent_open2(fs, ino, inode, &handle); 164 if (retval) 165 goto done; 166 if (bmap_flags & BMAP_SET) { 167 retval = ext2fs_extent_set_bmap(handle, block, 168 *phys_blk, 0); 169 goto done; 170 } 171 retval = ext2fs_extent_goto(handle, block); 172 if (retval) { 173 /* If the extent is not found, return phys_blk = 0 */ 174 if (retval == EXT2_ET_EXTENT_NOT_FOUND) 175 goto got_block; 176 goto done; 177 } 178 retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent); 179 if (retval) 180 goto done; 181 offset = block - extent.e_lblk; 182 if (block >= extent.e_lblk && (offset <= extent.e_len)) { 183 *phys_blk = extent.e_pblk + offset; 184 if (ret_flags && extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT) 185 *ret_flags |= BMAP_RET_UNINIT; 186 } 187 got_block: 188 if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) { 189 retval = ext2fs_alloc_block(fs, b, block_buf, &b); 190 if (retval) 191 goto done; 192 retval = ext2fs_extent_set_bmap(handle, block, 193 (blk64_t) b, 0); 194 if (retval) 195 goto done; 196 /* Update inode after setting extent */ 197 retval = ext2fs_read_inode(fs, ino, inode); 198 if (retval) 199 return retval; 200 blocks_alloc++; 201 *phys_blk = b; 202 } 203 retval = 0; 204 goto done; 205 } 206 207 if (!block_buf) { 208 retval = ext2fs_get_array(2, fs->blocksize, &buf); 209 if (retval) 210 return retval; 211 block_buf = buf; 212 } 213 214 if (block < EXT2_NDIR_BLOCKS) { 215 if (bmap_flags & BMAP_SET) { 216 b = *phys_blk; 217 inode_bmap(inode, block) = b; 218 inode_dirty++; 219 goto done; 220 } 221 222 *phys_blk = inode_bmap(inode, block); 223 b = block ? inode_bmap(inode, block-1) : 0; 224 225 if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) { 226 retval = ext2fs_alloc_block(fs, b, block_buf, &b); 227 if (retval) 228 goto done; 229 inode_bmap(inode, block) = b; 230 blocks_alloc++; 231 *phys_blk = b; 232 } 233 goto done; 234 } 235 236 /* Indirect block */ 237 block -= EXT2_NDIR_BLOCKS; 238 blk32 = *phys_blk; 239 if (block < addr_per_block) { 240 b = inode_bmap(inode, EXT2_IND_BLOCK); 241 if (!b) { 242 if (!(bmap_flags & BMAP_ALLOC)) { 243 if (bmap_flags & BMAP_SET) 244 retval = EXT2_ET_SET_BMAP_NO_IND; 245 goto done; 246 } 247 248 b = inode_bmap(inode, EXT2_IND_BLOCK-1); 249 retval = ext2fs_alloc_block(fs, b, block_buf, &b); 250 if (retval) 251 goto done; 252 inode_bmap(inode, EXT2_IND_BLOCK) = b; 253 blocks_alloc++; 254 } 255 retval = block_ind_bmap(fs, bmap_flags, b, block_buf, 256 &blocks_alloc, block, &blk32); 257 if (retval == 0) 258 *phys_blk = blk32; 259 goto done; 260 } 261 262 /* Doubly indirect block */ 263 block -= addr_per_block; 264 if (block < addr_per_block * addr_per_block) { 265 b = inode_bmap(inode, EXT2_DIND_BLOCK); 266 if (!b) { 267 if (!(bmap_flags & BMAP_ALLOC)) { 268 if (bmap_flags & BMAP_SET) 269 retval = EXT2_ET_SET_BMAP_NO_IND; 270 goto done; 271 } 272 273 b = inode_bmap(inode, EXT2_IND_BLOCK); 274 retval = ext2fs_alloc_block(fs, b, block_buf, &b); 275 if (retval) 276 goto done; 277 inode_bmap(inode, EXT2_DIND_BLOCK) = b; 278 blocks_alloc++; 279 } 280 retval = block_dind_bmap(fs, bmap_flags, b, block_buf, 281 &blocks_alloc, block, &blk32); 282 if (retval == 0) 283 *phys_blk = blk32; 284 goto done; 285 } 286 287 /* Triply indirect block */ 288 block -= addr_per_block * addr_per_block; 289 b = inode_bmap(inode, EXT2_TIND_BLOCK); 290 if (!b) { 291 if (!(bmap_flags & BMAP_ALLOC)) { 292 if (bmap_flags & BMAP_SET) 293 retval = EXT2_ET_SET_BMAP_NO_IND; 294 goto done; 295 } 296 297 b = inode_bmap(inode, EXT2_DIND_BLOCK); 298 retval = ext2fs_alloc_block(fs, b, block_buf, &b); 299 if (retval) 300 goto done; 301 inode_bmap(inode, EXT2_TIND_BLOCK) = b; 302 blocks_alloc++; 303 } 304 retval = block_tind_bmap(fs, bmap_flags, b, block_buf, 305 &blocks_alloc, block, &blk32); 306 if (retval == 0) 307 *phys_blk = blk32; 308 done: 309 if (buf) 310 ext2fs_free_mem(&buf); 311 if (handle) 312 ext2fs_extent_free(handle); 313 if ((retval == 0) && (blocks_alloc || inode_dirty)) { 314 ext2fs_iblk_add_blocks(fs, inode, blocks_alloc); 315 retval = ext2fs_write_inode(fs, ino, inode); 316 } 317 return retval; 318 } 319 320 errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode, 321 char *block_buf, int bmap_flags, blk_t block, 322 blk_t *phys_blk) 323 { 324 errcode_t ret; 325 blk64_t ret_blk = *phys_blk; 326 327 ret = ext2fs_bmap2(fs, ino, inode, block_buf, bmap_flags, block, 328 0, &ret_blk); 329 if (ret) 330 return ret; 331 if (ret_blk >= ((long long) 1 << 32)) 332 return EOVERFLOW; 333 *phys_blk = ret_blk; 334 return 0; 335 } 336
