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
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 */
squashfs_new_inode(struct super_block * sb,struct inode * inode,struct squashfs_base_inode * sqsh_ino)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
squashfs_iget(struct super_block * sb,long long ino,unsigned int ino_number)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 */
squashfs_read_inode(struct inode * inode,long long ino)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 set_nlink(inode, 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 set_nlink(inode, 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) + 511) >> 9;
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 set_nlink(inode, 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 set_nlink(inode, 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 set_nlink(inode, 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 set_nlink(inode, 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 set_nlink(inode, 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 set_nlink(inode, 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 set_nlink(inode, 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