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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> | |
6545b246 PL |
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: { | |
f4f8056a RK |
135 | unsigned int frag_offset, frag; |
136 | int frag_size; | |
6545b246 PL |
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: { | |
f4f8056a RK |
178 | unsigned int frag_offset, frag; |
179 | int frag_size; | |
6545b246 PL |
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 | } |