1 /* 2 * Squashfs - a compressed read only filesystem for Linux 3 * 4 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008 5 * Phillip Lougher <phillip@lougher.demon.co.uk> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 2, 10 * or (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 20 * 21 * inode.c 22 */ 23 24 /* 25 * This file implements code to create and read inodes from disk. 26 * 27 * Inodes in Squashfs are identified by a 48-bit inode which encodes the 28 * location of the compressed metadata block containing the inode, and the byte 29 * offset into that block where the inode is placed (<block, offset>). 30 * 31 * To maximise compression there are different inodes for each file type 32 * (regular file, directory, device, etc.), the inode contents and length 33 * varying with the type. 34 * 35 * To further maximise compression, two types of regular file inode and 36 * directory inode are defined: inodes optimised for frequently occurring 37 * regular files and directories, and extended types where extra 38 * information has to be stored. 39 */ 40 41 #include <linux/fs.h> 42 #include <linux/vfs.h> 43 #include <linux/xattr.h> 44 45 #include "squashfs_fs.h" 46 #include "squashfs_fs_sb.h" 47 #include "squashfs_fs_i.h" 48 #include "squashfs.h" 49 #include "xattr.h" 50 51 /* 52 * Initialise VFS inode with the base inode information common to all 53 * Squashfs inode types. Sqsh_ino contains the unswapped base inode 54 * off disk. 55 */ 56 static int squashfs_new_inode(struct super_block *sb, struct inode *inode, 57 struct squashfs_base_inode *sqsh_ino) 58 { 59 int err; 60 61 err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &inode->i_uid); 62 if (err) 63 return err; 64 65 err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &inode->i_gid); 66 if (err) 67 return err; 68 69 inode->i_ino = le32_to_cpu(sqsh_ino->inode_number); 70 inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime); 71 inode->i_atime.tv_sec = inode->i_mtime.tv_sec; 72 inode->i_ctime.tv_sec = inode->i_mtime.tv_sec; 73 inode->i_mode = le16_to_cpu(sqsh_ino->mode); 74 inode->i_size = 0; 75 76 return err; 77 } 78 79 80 struct inode *squashfs_iget(struct super_block *sb, long long ino, 81 unsigned int ino_number) 82 { 83 struct inode *inode = iget_locked(sb, ino_number); 84 int err; 85 86 TRACE("Entered squashfs_iget\n"); 87 88 if (!inode) 89 return ERR_PTR(-ENOMEM); 90 if (!(inode->i_state & I_NEW)) 91 return inode; 92 93 err = squashfs_read_inode(inode, ino); 94 if (err) { 95 iget_failed(inode); 96 return ERR_PTR(err); 97 } 98 99 unlock_new_inode(inode); 100 return inode; 101 } 102 103 104 /* 105 * Initialise VFS inode by reading inode from inode table (compressed 106 * metadata). The format and amount of data read depends on type. 107 */ 108 int squashfs_read_inode(struct inode *inode, long long ino) 109 { 110 struct super_block *sb = inode->i_sb; 111 struct squashfs_sb_info *msblk = sb->s_fs_info; 112 u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table; 113 int err, type, offset = SQUASHFS_INODE_OFFSET(ino); 114 union squashfs_inode squashfs_ino; 115 struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base; 116 int xattr_id = SQUASHFS_INVALID_XATTR; 117 118 TRACE("Entered squashfs_read_inode\n"); 119 120 /* 121 * Read inode base common to all inode types. 122 */ 123 err = squashfs_read_metadata(sb, sqshb_ino, &block, 124 &offset, sizeof(*sqshb_ino)); 125 if (err < 0) 126 goto failed_read; 127 128 err = squashfs_new_inode(sb, inode, sqshb_ino); 129 if (err) 130 goto failed_read; 131 132 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table; 133 offset = SQUASHFS_INODE_OFFSET(ino); 134 135 type = le16_to_cpu(sqshb_ino->inode_type); 136 switch (type) { 137 case SQUASHFS_REG_TYPE: { 138 unsigned int frag_offset, frag; 139 int frag_size; 140 u64 frag_blk; 141 struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg; 142 143 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 144 sizeof(*sqsh_ino)); 145 if (err < 0) 146 goto failed_read; 147 148 frag = le32_to_cpu(sqsh_ino->fragment); 149 if (frag != SQUASHFS_INVALID_FRAG) { 150 frag_offset = le32_to_cpu(sqsh_ino->offset); 151 frag_size = squashfs_frag_lookup(sb, frag, &frag_blk); 152 if (frag_size < 0) { 153 err = frag_size; 154 goto failed_read; 155 } 156 } else { 157 frag_blk = SQUASHFS_INVALID_BLK; 158 frag_size = 0; 159 frag_offset = 0; 160 } 161 162 inode->i_nlink = 1; 163 inode->i_size = le32_to_cpu(sqsh_ino->file_size); 164 inode->i_fop = &generic_ro_fops; 165 inode->i_mode |= S_IFREG; 166 inode->i_blocks = ((inode->i_size - 1) >> 9) + 1; 167 squashfs_i(inode)->fragment_block = frag_blk; 168 squashfs_i(inode)->fragment_size = frag_size; 169 squashfs_i(inode)->fragment_offset = frag_offset; 170 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); 171 squashfs_i(inode)->block_list_start = block; 172 squashfs_i(inode)->offset = offset; 173 inode->i_data.a_ops = &squashfs_aops; 174 175 TRACE("File inode %x:%x, start_block %llx, block_list_start " 176 "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino), 177 offset, squashfs_i(inode)->start, block, offset); 178 break; 179 } 180 case SQUASHFS_LREG_TYPE: { 181 unsigned int frag_offset, frag; 182 int frag_size; 183 u64 frag_blk; 184 struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg; 185 186 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 187 sizeof(*sqsh_ino)); 188 if (err < 0) 189 goto failed_read; 190 191 frag = le32_to_cpu(sqsh_ino->fragment); 192 if (frag != SQUASHFS_INVALID_FRAG) { 193 frag_offset = le32_to_cpu(sqsh_ino->offset); 194 frag_size = squashfs_frag_lookup(sb, frag, &frag_blk); 195 if (frag_size < 0) { 196 err = frag_size; 197 goto failed_read; 198 } 199 } else { 200 frag_blk = SQUASHFS_INVALID_BLK; 201 frag_size = 0; 202 frag_offset = 0; 203 } 204 205 xattr_id = le32_to_cpu(sqsh_ino->xattr); 206 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 207 inode->i_size = le64_to_cpu(sqsh_ino->file_size); 208 inode->i_op = &squashfs_inode_ops; 209 inode->i_fop = &generic_ro_fops; 210 inode->i_mode |= S_IFREG; 211 inode->i_blocks = ((inode->i_size - 212 le64_to_cpu(sqsh_ino->sparse) - 1) >> 9) + 1; 213 214 squashfs_i(inode)->fragment_block = frag_blk; 215 squashfs_i(inode)->fragment_size = frag_size; 216 squashfs_i(inode)->fragment_offset = frag_offset; 217 squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block); 218 squashfs_i(inode)->block_list_start = block; 219 squashfs_i(inode)->offset = offset; 220 inode->i_data.a_ops = &squashfs_aops; 221 222 TRACE("File inode %x:%x, start_block %llx, block_list_start " 223 "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino), 224 offset, squashfs_i(inode)->start, block, offset); 225 break; 226 } 227 case SQUASHFS_DIR_TYPE: { 228 struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir; 229 230 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 231 sizeof(*sqsh_ino)); 232 if (err < 0) 233 goto failed_read; 234 235 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 236 inode->i_size = le16_to_cpu(sqsh_ino->file_size); 237 inode->i_op = &squashfs_dir_inode_ops; 238 inode->i_fop = &squashfs_dir_ops; 239 inode->i_mode |= S_IFDIR; 240 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); 241 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset); 242 squashfs_i(inode)->dir_idx_cnt = 0; 243 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode); 244 245 TRACE("Directory inode %x:%x, start_block %llx, offset %x\n", 246 SQUASHFS_INODE_BLK(ino), offset, 247 squashfs_i(inode)->start, 248 le16_to_cpu(sqsh_ino->offset)); 249 break; 250 } 251 case SQUASHFS_LDIR_TYPE: { 252 struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir; 253 254 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 255 sizeof(*sqsh_ino)); 256 if (err < 0) 257 goto failed_read; 258 259 xattr_id = le32_to_cpu(sqsh_ino->xattr); 260 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 261 inode->i_size = le32_to_cpu(sqsh_ino->file_size); 262 inode->i_op = &squashfs_dir_inode_ops; 263 inode->i_fop = &squashfs_dir_ops; 264 inode->i_mode |= S_IFDIR; 265 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); 266 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset); 267 squashfs_i(inode)->dir_idx_start = block; 268 squashfs_i(inode)->dir_idx_offset = offset; 269 squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count); 270 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode); 271 272 TRACE("Long directory inode %x:%x, start_block %llx, offset " 273 "%x\n", SQUASHFS_INODE_BLK(ino), offset, 274 squashfs_i(inode)->start, 275 le16_to_cpu(sqsh_ino->offset)); 276 break; 277 } 278 case SQUASHFS_SYMLINK_TYPE: 279 case SQUASHFS_LSYMLINK_TYPE: { 280 struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink; 281 282 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 283 sizeof(*sqsh_ino)); 284 if (err < 0) 285 goto failed_read; 286 287 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 288 inode->i_size = le32_to_cpu(sqsh_ino->symlink_size); 289 inode->i_op = &squashfs_symlink_inode_ops; 290 inode->i_data.a_ops = &squashfs_symlink_aops; 291 inode->i_mode |= S_IFLNK; 292 squashfs_i(inode)->start = block; 293 squashfs_i(inode)->offset = offset; 294 295 if (type == SQUASHFS_LSYMLINK_TYPE) { 296 __le32 xattr; 297 298 err = squashfs_read_metadata(sb, NULL, &block, 299 &offset, inode->i_size); 300 if (err < 0) 301 goto failed_read; 302 err = squashfs_read_metadata(sb, &xattr, &block, 303 &offset, sizeof(xattr)); 304 if (err < 0) 305 goto failed_read; 306 xattr_id = le32_to_cpu(xattr); 307 } 308 309 TRACE("Symbolic link inode %x:%x, start_block %llx, offset " 310 "%x\n", SQUASHFS_INODE_BLK(ino), offset, 311 block, offset); 312 break; 313 } 314 case SQUASHFS_BLKDEV_TYPE: 315 case SQUASHFS_CHRDEV_TYPE: { 316 struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev; 317 unsigned int rdev; 318 319 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 320 sizeof(*sqsh_ino)); 321 if (err < 0) 322 goto failed_read; 323 324 if (type == SQUASHFS_CHRDEV_TYPE) 325 inode->i_mode |= S_IFCHR; 326 else 327 inode->i_mode |= S_IFBLK; 328 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 329 rdev = le32_to_cpu(sqsh_ino->rdev); 330 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev)); 331 332 TRACE("Device inode %x:%x, rdev %x\n", 333 SQUASHFS_INODE_BLK(ino), offset, rdev); 334 break; 335 } 336 case SQUASHFS_LBLKDEV_TYPE: 337 case SQUASHFS_LCHRDEV_TYPE: { 338 struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev; 339 unsigned int rdev; 340 341 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 342 sizeof(*sqsh_ino)); 343 if (err < 0) 344 goto failed_read; 345 346 if (type == SQUASHFS_LCHRDEV_TYPE) 347 inode->i_mode |= S_IFCHR; 348 else 349 inode->i_mode |= S_IFBLK; 350 xattr_id = le32_to_cpu(sqsh_ino->xattr); 351 inode->i_op = &squashfs_inode_ops; 352 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 353 rdev = le32_to_cpu(sqsh_ino->rdev); 354 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev)); 355 356 TRACE("Device inode %x:%x, rdev %x\n", 357 SQUASHFS_INODE_BLK(ino), offset, rdev); 358 break; 359 } 360 case SQUASHFS_FIFO_TYPE: 361 case SQUASHFS_SOCKET_TYPE: { 362 struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc; 363 364 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 365 sizeof(*sqsh_ino)); 366 if (err < 0) 367 goto failed_read; 368 369 if (type == SQUASHFS_FIFO_TYPE) 370 inode->i_mode |= S_IFIFO; 371 else 372 inode->i_mode |= S_IFSOCK; 373 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 374 init_special_inode(inode, inode->i_mode, 0); 375 break; 376 } 377 case SQUASHFS_LFIFO_TYPE: 378 case SQUASHFS_LSOCKET_TYPE: { 379 struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc; 380 381 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 382 sizeof(*sqsh_ino)); 383 if (err < 0) 384 goto failed_read; 385 386 if (type == SQUASHFS_LFIFO_TYPE) 387 inode->i_mode |= S_IFIFO; 388 else 389 inode->i_mode |= S_IFSOCK; 390 xattr_id = le32_to_cpu(sqsh_ino->xattr); 391 inode->i_op = &squashfs_inode_ops; 392 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); 393 init_special_inode(inode, inode->i_mode, 0); 394 break; 395 } 396 default: 397 ERROR("Unknown inode type %d in squashfs_iget!\n", type); 398 return -EINVAL; 399 } 400 401 if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) { 402 err = squashfs_xattr_lookup(sb, xattr_id, 403 &squashfs_i(inode)->xattr_count, 404 &squashfs_i(inode)->xattr_size, 405 &squashfs_i(inode)->xattr); 406 if (err < 0) 407 goto failed_read; 408 inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9) 409 + 1; 410 } else 411 squashfs_i(inode)->xattr_count = 0; 412 413 return 0; 414 415 failed_read: 416 ERROR("Unable to read inode 0x%llx\n", ino); 417 return err; 418 } 419 420 421 const struct inode_operations squashfs_inode_ops = { 422 .getxattr = generic_getxattr, 423 .listxattr = squashfs_listxattr 424 }; 425 426