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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 | |
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: { |
135 | unsigned int frag_offset, frag; |
136 | int frag_size; |
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; |
179 | int frag_size; |
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 | } |
348 |
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