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