]>
Commit | Line | Data |
---|---|---|
6545b246 PL |
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 | */ | |
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 | ||
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 | */ | |
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: { | |
f4f8056a RK |
136 | unsigned int frag_offset, frag; |
137 | int frag_size; | |
6545b246 PL |
138 | u64 frag_blk; |
139 | struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg; | |
140 | ||
141 | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | |
142 | sizeof(*sqsh_ino)); | |
143 | if (err < 0) | |
144 | goto failed_read; | |
145 | ||
146 | frag = le32_to_cpu(sqsh_ino->fragment); | |
147 | if (frag != SQUASHFS_INVALID_FRAG) { | |
148 | frag_offset = le32_to_cpu(sqsh_ino->offset); | |
149 | frag_size = squashfs_frag_lookup(sb, frag, &frag_blk); | |
150 | if (frag_size < 0) { | |
151 | err = frag_size; | |
152 | goto failed_read; | |
153 | } | |
154 | } else { | |
155 | frag_blk = SQUASHFS_INVALID_BLK; | |
156 | frag_size = 0; | |
157 | frag_offset = 0; | |
158 | } | |
159 | ||
160 | inode->i_nlink = 1; | |
161 | inode->i_size = le32_to_cpu(sqsh_ino->file_size); | |
162 | inode->i_fop = &generic_ro_fops; | |
163 | inode->i_mode |= S_IFREG; | |
164 | inode->i_blocks = ((inode->i_size - 1) >> 9) + 1; | |
165 | squashfs_i(inode)->fragment_block = frag_blk; | |
166 | squashfs_i(inode)->fragment_size = frag_size; | |
167 | squashfs_i(inode)->fragment_offset = frag_offset; | |
168 | squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); | |
169 | squashfs_i(inode)->block_list_start = block; | |
170 | squashfs_i(inode)->offset = offset; | |
171 | inode->i_data.a_ops = &squashfs_aops; | |
172 | ||
173 | TRACE("File inode %x:%x, start_block %llx, block_list_start " | |
174 | "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino), | |
175 | offset, squashfs_i(inode)->start, block, offset); | |
176 | break; | |
177 | } | |
178 | case SQUASHFS_LREG_TYPE: { | |
f4f8056a RK |
179 | unsigned int frag_offset, frag; |
180 | int frag_size; | |
6545b246 PL |
181 | u64 frag_blk; |
182 | struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg; | |
183 | ||
184 | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | |
185 | sizeof(*sqsh_ino)); | |
186 | if (err < 0) | |
187 | goto failed_read; | |
188 | ||
189 | frag = le32_to_cpu(sqsh_ino->fragment); | |
190 | if (frag != SQUASHFS_INVALID_FRAG) { | |
191 | frag_offset = le32_to_cpu(sqsh_ino->offset); | |
192 | frag_size = squashfs_frag_lookup(sb, frag, &frag_blk); | |
193 | if (frag_size < 0) { | |
194 | err = frag_size; | |
195 | goto failed_read; | |
196 | } | |
197 | } else { | |
198 | frag_blk = SQUASHFS_INVALID_BLK; | |
199 | frag_size = 0; | |
200 | frag_offset = 0; | |
201 | } | |
202 | ||
203 | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | |
204 | inode->i_size = le64_to_cpu(sqsh_ino->file_size); | |
205 | inode->i_fop = &generic_ro_fops; | |
206 | inode->i_mode |= S_IFREG; | |
207 | inode->i_blocks = ((inode->i_size - | |
208 | le64_to_cpu(sqsh_ino->sparse) - 1) >> 9) + 1; | |
209 | ||
210 | squashfs_i(inode)->fragment_block = frag_blk; | |
211 | squashfs_i(inode)->fragment_size = frag_size; | |
212 | squashfs_i(inode)->fragment_offset = frag_offset; | |
213 | squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block); | |
214 | squashfs_i(inode)->block_list_start = block; | |
215 | squashfs_i(inode)->offset = offset; | |
216 | inode->i_data.a_ops = &squashfs_aops; | |
217 | ||
218 | TRACE("File inode %x:%x, start_block %llx, block_list_start " | |
219 | "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino), | |
220 | offset, squashfs_i(inode)->start, block, offset); | |
221 | break; | |
222 | } | |
223 | case SQUASHFS_DIR_TYPE: { | |
224 | struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir; | |
225 | ||
226 | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | |
227 | sizeof(*sqsh_ino)); | |
228 | if (err < 0) | |
229 | goto failed_read; | |
230 | ||
231 | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | |
232 | inode->i_size = le16_to_cpu(sqsh_ino->file_size); | |
233 | inode->i_op = &squashfs_dir_inode_ops; | |
234 | inode->i_fop = &squashfs_dir_ops; | |
235 | inode->i_mode |= S_IFDIR; | |
236 | squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); | |
237 | squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset); | |
238 | squashfs_i(inode)->dir_idx_cnt = 0; | |
239 | squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode); | |
240 | ||
241 | TRACE("Directory inode %x:%x, start_block %llx, offset %x\n", | |
242 | SQUASHFS_INODE_BLK(ino), offset, | |
243 | squashfs_i(inode)->start, | |
244 | le16_to_cpu(sqsh_ino->offset)); | |
245 | break; | |
246 | } | |
247 | case SQUASHFS_LDIR_TYPE: { | |
248 | struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir; | |
249 | ||
250 | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | |
251 | sizeof(*sqsh_ino)); | |
252 | if (err < 0) | |
253 | goto failed_read; | |
254 | ||
255 | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | |
256 | inode->i_size = le32_to_cpu(sqsh_ino->file_size); | |
257 | inode->i_op = &squashfs_dir_inode_ops; | |
258 | inode->i_fop = &squashfs_dir_ops; | |
259 | inode->i_mode |= S_IFDIR; | |
260 | squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); | |
261 | squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset); | |
262 | squashfs_i(inode)->dir_idx_start = block; | |
263 | squashfs_i(inode)->dir_idx_offset = offset; | |
264 | squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count); | |
265 | squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode); | |
266 | ||
267 | TRACE("Long directory inode %x:%x, start_block %llx, offset " | |
268 | "%x\n", SQUASHFS_INODE_BLK(ino), offset, | |
269 | squashfs_i(inode)->start, | |
270 | le16_to_cpu(sqsh_ino->offset)); | |
271 | break; | |
272 | } | |
273 | case SQUASHFS_SYMLINK_TYPE: | |
274 | case SQUASHFS_LSYMLINK_TYPE: { | |
275 | struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink; | |
276 | ||
277 | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | |
278 | sizeof(*sqsh_ino)); | |
279 | if (err < 0) | |
280 | goto failed_read; | |
281 | ||
282 | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | |
283 | inode->i_size = le32_to_cpu(sqsh_ino->symlink_size); | |
284 | inode->i_op = &page_symlink_inode_operations; | |
285 | inode->i_data.a_ops = &squashfs_symlink_aops; | |
286 | inode->i_mode |= S_IFLNK; | |
287 | squashfs_i(inode)->start = block; | |
288 | squashfs_i(inode)->offset = offset; | |
289 | ||
290 | TRACE("Symbolic link inode %x:%x, start_block %llx, offset " | |
291 | "%x\n", SQUASHFS_INODE_BLK(ino), offset, | |
292 | block, offset); | |
293 | break; | |
294 | } | |
295 | case SQUASHFS_BLKDEV_TYPE: | |
296 | case SQUASHFS_CHRDEV_TYPE: | |
297 | case SQUASHFS_LBLKDEV_TYPE: | |
298 | case SQUASHFS_LCHRDEV_TYPE: { | |
299 | struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev; | |
300 | unsigned int rdev; | |
301 | ||
302 | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | |
303 | sizeof(*sqsh_ino)); | |
304 | if (err < 0) | |
305 | goto failed_read; | |
306 | ||
307 | if (type == SQUASHFS_CHRDEV_TYPE) | |
308 | inode->i_mode |= S_IFCHR; | |
309 | else | |
310 | inode->i_mode |= S_IFBLK; | |
311 | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | |
312 | rdev = le32_to_cpu(sqsh_ino->rdev); | |
313 | init_special_inode(inode, inode->i_mode, new_decode_dev(rdev)); | |
314 | ||
315 | TRACE("Device inode %x:%x, rdev %x\n", | |
316 | SQUASHFS_INODE_BLK(ino), offset, rdev); | |
317 | break; | |
318 | } | |
319 | case SQUASHFS_FIFO_TYPE: | |
320 | case SQUASHFS_SOCKET_TYPE: | |
321 | case SQUASHFS_LFIFO_TYPE: | |
322 | case SQUASHFS_LSOCKET_TYPE: { | |
323 | struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc; | |
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_FIFO_TYPE) | |
331 | inode->i_mode |= S_IFIFO; | |
332 | else | |
333 | inode->i_mode |= S_IFSOCK; | |
334 | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | |
335 | init_special_inode(inode, inode->i_mode, 0); | |
336 | break; | |
337 | } | |
338 | default: | |
339 | ERROR("Unknown inode type %d in squashfs_iget!\n", type); | |
340 | return -EINVAL; | |
341 | } | |
342 | ||
343 | return 0; | |
344 | ||
345 | failed_read: | |
346 | ERROR("Unable to read inode 0x%llx\n", ino); | |
347 | return err; | |
348 | } |