Commit | Line | Data |
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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> | |
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: { | |
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 | } |