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