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@squashfs.org.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 #include <linux/pagemap.h> 45 46 #include "squashfs_fs.h" 47 #include "squashfs_fs_sb.h" 48 #include "squashfs_fs_i.h" 49 #include "squashfs.h" 50 #include "xattr.h" 51 52 /* 53 * Initialise VFS inode with the base inode information common to all 54 * Squashfs inode types. Sqsh_ino contains the unswapped base inode 55 * off disk. 56 */ 57 static int squashfs_new_inode(struct super_block *sb, struct inode *inode, 58 struct squashfs_base_inode *sqsh_ino) 59 { 60 uid_t i_uid; 61 gid_t i_gid; 62 int err; 63 64 err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &i_uid); 65 if (err) 66 return err; 67 68 err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &i_gid); 69 if (err) 70 return err; 71 72 i_uid_write(inode, i_uid); 73 i_gid_write(inode, i_gid); 74 inode->i_ino = le32_to_cpu(sqsh_ino->inode_number); 75 inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime); 76 inode->i_atime.tv_sec = inode->i_mtime.tv_sec; 77 inode->i_ctime.tv_sec = inode->i_mtime.tv_sec; 78 inode->i_mode = le16_to_cpu(sqsh_ino->mode); 79 inode->i_size = 0; 80 81 return err; 82 } 83 84 85 struct inode *squashfs_iget(struct super_block *sb, long long ino, 86 unsigned int ino_number) 87 { 88 struct inode *inode = iget_locked(sb, ino_number); 89 int err; 90 91 TRACE("Entered squashfs_iget\n"); 92 93 if (!inode) 94 return ERR_PTR(-ENOMEM); 95 if (!(inode->i_state & I_NEW)) 96 return inode; 97 98 err = squashfs_read_inode(inode, ino); 99 if (err) { 100 iget_failed(inode); 101 return ERR_PTR(err); 102 } 103 104 unlock_new_inode(inode); 105 return inode; 106 } 107 108 109 /* 110 * Initialise VFS inode by reading inode from inode table (compressed 111 * metadata). The format and amount of data read depends on type. 112 */ 113 int squashfs_read_inode(struct inode *inode, long long ino) 114 { 115 struct super_block *sb = inode->i_sb; 116 struct squashfs_sb_info *msblk = sb->s_fs_info; 117 u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table; 118 int err, type, offset = SQUASHFS_INODE_OFFSET(ino); 119 union squashfs_inode squashfs_ino; 120 struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base; 121 int xattr_id = SQUASHFS_INVALID_XATTR; 122 123 TRACE("Entered squashfs_read_inode\n"); 124 125 /* 126 * Read inode base common to all inode types. 127 */ 128 err = squashfs_read_metadata(sb, sqshb_ino, &block, 129 &offset, sizeof(*sqshb_ino)); 130 if (err < 0) 131 goto failed_read; 132 133 err = squashfs_new_inode(sb, inode, sqshb_ino); 134 if (err) 135 goto failed_read; 136 137 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table; 138 offset = SQUASHFS_INODE_OFFSET(ino); 139 140 type = le16_to_cpu(sqshb_ino->inode_type); 141 switch (type) { 142 case SQUASHFS_REG_TYPE: { 143 unsigned int frag_offset, frag; 144 int frag_size; 145 u64 frag_blk; 146 struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg; 147 148 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 149 sizeof(*sqsh_ino)); 150 if (err < 0) 151 goto failed_read; 152 153 frag = le32_to_cpu(sqsh_ino->fragment); 154 if (frag != SQUASHFS_INVALID_FRAG) { 155 frag_offset = le32_to_cpu(sqsh_ino->offset); 156 frag_size = squashfs_frag_lookup(sb, frag, &frag_blk); 157 if (frag_size < 0) { 158 err = frag_size; 159 goto failed_read; 160 } 161 } else { 162 frag_blk = SQUASHFS_INVALID_BLK; 163 frag_size = 0; 164 frag_offset = 0; 165 } 166 167 set_nlink(inode, 1); 168 inode->i_size = le32_to_cpu(sqsh_ino->file_size); 169 inode->i_fop = &generic_ro_fops; 170 inode->i_mode |= S_IFREG; 171 inode->i_blocks = ((inode->i_size - 1) >> 9) + 1; 172 squashfs_i(inode)->fragment_block = frag_blk; 173 squashfs_i(inode)->fragment_size = frag_size; 174 squashfs_i(inode)->fragment_offset = frag_offset; 175 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); 176 squashfs_i(inode)->block_list_start = block; 177 squashfs_i(inode)->offset = offset; 178 inode->i_data.a_ops = &squashfs_aops; 179 180 TRACE("File inode %x:%x, start_block %llx, block_list_start " 181 "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino), 182 offset, squashfs_i(inode)->start, block, offset); 183 break; 184 } 185 case SQUASHFS_LREG_TYPE: { 186 unsigned int frag_offset, frag; 187 int frag_size; 188 u64 frag_blk; 189 struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg; 190 191 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 192 sizeof(*sqsh_ino)); 193 if (err < 0) 194 goto failed_read; 195 196 frag = le32_to_cpu(sqsh_ino->fragment); 197 if (frag != SQUASHFS_INVALID_FRAG) { 198 frag_offset = le32_to_cpu(sqsh_ino->offset); 199 frag_size = squashfs_frag_lookup(sb, frag, &frag_blk); 200 if (frag_size < 0) { 201 err = frag_size; 202 goto failed_read; 203 } 204 } else { 205 frag_blk = SQUASHFS_INVALID_BLK; 206 frag_size = 0; 207 frag_offset = 0; 208 } 209 210 xattr_id = le32_to_cpu(sqsh_ino->xattr); 211 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); 212 inode->i_size = le64_to_cpu(sqsh_ino->file_size); 213 inode->i_op = &squashfs_inode_ops; 214 inode->i_fop = &generic_ro_fops; 215 inode->i_mode |= S_IFREG; 216 inode->i_blocks = (inode->i_size - 217 le64_to_cpu(sqsh_ino->sparse) + 511) >> 9; 218 219 squashfs_i(inode)->fragment_block = frag_blk; 220 squashfs_i(inode)->fragment_size = frag_size; 221 squashfs_i(inode)->fragment_offset = frag_offset; 222 squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block); 223 squashfs_i(inode)->block_list_start = block; 224 squashfs_i(inode)->offset = offset; 225 inode->i_data.a_ops = &squashfs_aops; 226 227 TRACE("File inode %x:%x, start_block %llx, block_list_start " 228 "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino), 229 offset, squashfs_i(inode)->start, block, offset); 230 break; 231 } 232 case SQUASHFS_DIR_TYPE: { 233 struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir; 234 235 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 236 sizeof(*sqsh_ino)); 237 if (err < 0) 238 goto failed_read; 239 240 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); 241 inode->i_size = le16_to_cpu(sqsh_ino->file_size); 242 inode->i_op = &squashfs_dir_inode_ops; 243 inode->i_fop = &squashfs_dir_ops; 244 inode->i_mode |= S_IFDIR; 245 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); 246 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset); 247 squashfs_i(inode)->dir_idx_cnt = 0; 248 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode); 249 250 TRACE("Directory inode %x:%x, start_block %llx, offset %x\n", 251 SQUASHFS_INODE_BLK(ino), offset, 252 squashfs_i(inode)->start, 253 le16_to_cpu(sqsh_ino->offset)); 254 break; 255 } 256 case SQUASHFS_LDIR_TYPE: { 257 struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir; 258 259 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 260 sizeof(*sqsh_ino)); 261 if (err < 0) 262 goto failed_read; 263 264 xattr_id = le32_to_cpu(sqsh_ino->xattr); 265 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); 266 inode->i_size = le32_to_cpu(sqsh_ino->file_size); 267 inode->i_op = &squashfs_dir_inode_ops; 268 inode->i_fop = &squashfs_dir_ops; 269 inode->i_mode |= S_IFDIR; 270 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); 271 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset); 272 squashfs_i(inode)->dir_idx_start = block; 273 squashfs_i(inode)->dir_idx_offset = offset; 274 squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count); 275 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode); 276 277 TRACE("Long directory inode %x:%x, start_block %llx, offset " 278 "%x\n", SQUASHFS_INODE_BLK(ino), offset, 279 squashfs_i(inode)->start, 280 le16_to_cpu(sqsh_ino->offset)); 281 break; 282 } 283 case SQUASHFS_SYMLINK_TYPE: 284 case SQUASHFS_LSYMLINK_TYPE: { 285 struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink; 286 287 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 288 sizeof(*sqsh_ino)); 289 if (err < 0) 290 goto failed_read; 291 292 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); 293 inode->i_size = le32_to_cpu(sqsh_ino->symlink_size); 294 inode->i_op = &squashfs_symlink_inode_ops; 295 inode_nohighmem(inode); 296 inode->i_data.a_ops = &squashfs_symlink_aops; 297 inode->i_mode |= S_IFLNK; 298 squashfs_i(inode)->start = block; 299 squashfs_i(inode)->offset = offset; 300 301 if (type == SQUASHFS_LSYMLINK_TYPE) { 302 __le32 xattr; 303 304 err = squashfs_read_metadata(sb, NULL, &block, 305 &offset, inode->i_size); 306 if (err < 0) 307 goto failed_read; 308 err = squashfs_read_metadata(sb, &xattr, &block, 309 &offset, sizeof(xattr)); 310 if (err < 0) 311 goto failed_read; 312 xattr_id = le32_to_cpu(xattr); 313 } 314 315 TRACE("Symbolic link inode %x:%x, start_block %llx, offset " 316 "%x\n", SQUASHFS_INODE_BLK(ino), offset, 317 block, offset); 318 break; 319 } 320 case SQUASHFS_BLKDEV_TYPE: 321 case SQUASHFS_CHRDEV_TYPE: { 322 struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev; 323 unsigned int rdev; 324 325 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 326 sizeof(*sqsh_ino)); 327 if (err < 0) 328 goto failed_read; 329 330 if (type == SQUASHFS_CHRDEV_TYPE) 331 inode->i_mode |= S_IFCHR; 332 else 333 inode->i_mode |= S_IFBLK; 334 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); 335 rdev = le32_to_cpu(sqsh_ino->rdev); 336 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev)); 337 338 TRACE("Device inode %x:%x, rdev %x\n", 339 SQUASHFS_INODE_BLK(ino), offset, rdev); 340 break; 341 } 342 case SQUASHFS_LBLKDEV_TYPE: 343 case SQUASHFS_LCHRDEV_TYPE: { 344 struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev; 345 unsigned int rdev; 346 347 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 348 sizeof(*sqsh_ino)); 349 if (err < 0) 350 goto failed_read; 351 352 if (type == SQUASHFS_LCHRDEV_TYPE) 353 inode->i_mode |= S_IFCHR; 354 else 355 inode->i_mode |= S_IFBLK; 356 xattr_id = le32_to_cpu(sqsh_ino->xattr); 357 inode->i_op = &squashfs_inode_ops; 358 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); 359 rdev = le32_to_cpu(sqsh_ino->rdev); 360 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev)); 361 362 TRACE("Device inode %x:%x, rdev %x\n", 363 SQUASHFS_INODE_BLK(ino), offset, rdev); 364 break; 365 } 366 case SQUASHFS_FIFO_TYPE: 367 case SQUASHFS_SOCKET_TYPE: { 368 struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc; 369 370 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 371 sizeof(*sqsh_ino)); 372 if (err < 0) 373 goto failed_read; 374 375 if (type == SQUASHFS_FIFO_TYPE) 376 inode->i_mode |= S_IFIFO; 377 else 378 inode->i_mode |= S_IFSOCK; 379 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); 380 init_special_inode(inode, inode->i_mode, 0); 381 break; 382 } 383 case SQUASHFS_LFIFO_TYPE: 384 case SQUASHFS_LSOCKET_TYPE: { 385 struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc; 386 387 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, 388 sizeof(*sqsh_ino)); 389 if (err < 0) 390 goto failed_read; 391 392 if (type == SQUASHFS_LFIFO_TYPE) 393 inode->i_mode |= S_IFIFO; 394 else 395 inode->i_mode |= S_IFSOCK; 396 xattr_id = le32_to_cpu(sqsh_ino->xattr); 397 inode->i_op = &squashfs_inode_ops; 398 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink)); 399 init_special_inode(inode, inode->i_mode, 0); 400 break; 401 } 402 default: 403 ERROR("Unknown inode type %d in squashfs_iget!\n", type); 404 return -EINVAL; 405 } 406 407 if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) { 408 err = squashfs_xattr_lookup(sb, xattr_id, 409 &squashfs_i(inode)->xattr_count, 410 &squashfs_i(inode)->xattr_size, 411 &squashfs_i(inode)->xattr); 412 if (err < 0) 413 goto failed_read; 414 inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9) 415 + 1; 416 } else 417 squashfs_i(inode)->xattr_count = 0; 418 419 return 0; 420 421 failed_read: 422 ERROR("Unable to read inode 0x%llx\n", ino); 423 return err; 424 } 425 426 427 const struct inode_operations squashfs_inode_ops = { 428 .listxattr = squashfs_listxattr 429 }; 430 431