1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Squashfs - a compressed read only filesystem for Linux
4 *
5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
6 * Phillip Lougher <phillip@squashfs.org.uk>
7 *
8 * inode.c
9 */
10
11/*
12 * This file implements code to create and read inodes from disk.
13 *
14 * Inodes in Squashfs are identified by a 48-bit inode which encodes the
15 * location of the compressed metadata block containing the inode, and the byte
16 * offset into that block where the inode is placed (<block, offset>).
17 *
18 * To maximise compression there are different inodes for each file type
19 * (regular file, directory, device, etc.), the inode contents and length
20 * varying with the type.
21 *
22 * To further maximise compression, two types of regular file inode and
23 * directory inode are defined: inodes optimised for frequently occurring
24 * regular files and directories, and extended types where extra
25 * information has to be stored.
26 */
27
28#include <linux/fs.h>
29#include <linux/vfs.h>
30#include <linux/xattr.h>
31#include <linux/pagemap.h>
32
33#include "squashfs_fs.h"
34#include "squashfs_fs_sb.h"
35#include "squashfs_fs_i.h"
36#include "squashfs.h"
37#include "xattr.h"
38
39/*
40 * Initialise VFS inode with the base inode information common to all
41 * Squashfs inode types. Sqsh_ino contains the unswapped base inode
42 * off disk.
43 */
44static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
45 struct squashfs_base_inode *sqsh_ino)
46{
47 uid_t i_uid;
48 gid_t i_gid;
49 int err;
50
51 err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &i_uid);
52 if (err)
53 return err;
54
55 err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &i_gid);
56 if (err)
57 return err;
58
59 i_uid_write(inode, uid: i_uid);
60 i_gid_write(inode, gid: i_gid);
61 inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
62 inode_set_mtime(inode, le32_to_cpu(sqsh_ino->mtime), nsec: 0);
63 inode_set_atime(inode, sec: inode_get_mtime_sec(inode), nsec: 0);
64 inode_set_ctime(inode, sec: inode_get_mtime_sec(inode), nsec: 0);
65 inode->i_mode = le16_to_cpu(sqsh_ino->mode);
66 inode->i_size = 0;
67
68 return err;
69}
70
71
72struct inode *squashfs_iget(struct super_block *sb, long long ino,
73 unsigned int ino_number)
74{
75 struct inode *inode = iget_locked(sb, ino_number);
76 int err;
77
78 TRACE("Entered squashfs_iget\n");
79
80 if (!inode)
81 return ERR_PTR(error: -ENOMEM);
82 if (!(inode->i_state & I_NEW))
83 return inode;
84
85 err = squashfs_read_inode(inode, ino);
86 if (err) {
87 iget_failed(inode);
88 return ERR_PTR(error: err);
89 }
90
91 unlock_new_inode(inode);
92 return inode;
93}
94
95
96/*
97 * Initialise VFS inode by reading inode from inode table (compressed
98 * metadata). The format and amount of data read depends on type.
99 */
100int squashfs_read_inode(struct inode *inode, long long ino)
101{
102 struct super_block *sb = inode->i_sb;
103 struct squashfs_sb_info *msblk = sb->s_fs_info;
104 u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
105 int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
106 union squashfs_inode squashfs_ino;
107 struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
108 int xattr_id = SQUASHFS_INVALID_XATTR;
109
110 TRACE("Entered squashfs_read_inode\n");
111
112 /*
113 * Read inode base common to all inode types.
114 */
115 err = squashfs_read_metadata(sb, sqshb_ino, &block,
116 &offset, sizeof(*sqshb_ino));
117 if (err < 0)
118 goto failed_read;
119
120 err = squashfs_new_inode(sb, inode, sqsh_ino: sqshb_ino);
121 if (err)
122 goto failed_read;
123
124 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
125 offset = SQUASHFS_INODE_OFFSET(ino);
126
127 type = le16_to_cpu(sqshb_ino->inode_type);
128 switch (type) {
129 case SQUASHFS_REG_TYPE: {
130 unsigned int frag_offset, frag;
131 int frag_size;
132 u64 frag_blk;
133 struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
134
135 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
136 sizeof(*sqsh_ino));
137 if (err < 0)
138 goto failed_read;
139
140 frag = le32_to_cpu(sqsh_ino->fragment);
141 if (frag != SQUASHFS_INVALID_FRAG) {
142 frag_offset = le32_to_cpu(sqsh_ino->offset);
143 frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
144 if (frag_size < 0) {
145 err = frag_size;
146 goto failed_read;
147 }
148 } else {
149 frag_blk = SQUASHFS_INVALID_BLK;
150 frag_size = 0;
151 frag_offset = 0;
152 }
153
154 set_nlink(inode, nlink: 1);
155 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
156 inode->i_fop = &generic_ro_fops;
157 inode->i_mode |= S_IFREG;
158 inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
159 squashfs_i(inode)->fragment_block = frag_blk;
160 squashfs_i(inode)->fragment_size = frag_size;
161 squashfs_i(inode)->fragment_offset = frag_offset;
162 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
163 squashfs_i(inode)->block_list_start = block;
164 squashfs_i(inode)->offset = offset;
165 inode->i_data.a_ops = &squashfs_aops;
166
167 TRACE("File inode %x:%x, start_block %llx, block_list_start "
168 "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
169 offset, squashfs_i(inode)->start, block, offset);
170 break;
171 }
172 case SQUASHFS_LREG_TYPE: {
173 unsigned int frag_offset, frag;
174 int frag_size;
175 u64 frag_blk;
176 struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
177
178 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
179 sizeof(*sqsh_ino));
180 if (err < 0)
181 goto failed_read;
182
183 frag = le32_to_cpu(sqsh_ino->fragment);
184 if (frag != SQUASHFS_INVALID_FRAG) {
185 frag_offset = le32_to_cpu(sqsh_ino->offset);
186 frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
187 if (frag_size < 0) {
188 err = frag_size;
189 goto failed_read;
190 }
191 } else {
192 frag_blk = SQUASHFS_INVALID_BLK;
193 frag_size = 0;
194 frag_offset = 0;
195 }
196
197 xattr_id = le32_to_cpu(sqsh_ino->xattr);
198 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
199 inode->i_size = le64_to_cpu(sqsh_ino->file_size);
200 inode->i_op = &squashfs_inode_ops;
201 inode->i_fop = &generic_ro_fops;
202 inode->i_mode |= S_IFREG;
203 inode->i_blocks = (inode->i_size -
204 le64_to_cpu(sqsh_ino->sparse) + 511) >> 9;
205
206 squashfs_i(inode)->fragment_block = frag_blk;
207 squashfs_i(inode)->fragment_size = frag_size;
208 squashfs_i(inode)->fragment_offset = frag_offset;
209 squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
210 squashfs_i(inode)->block_list_start = block;
211 squashfs_i(inode)->offset = offset;
212 inode->i_data.a_ops = &squashfs_aops;
213
214 TRACE("File inode %x:%x, start_block %llx, block_list_start "
215 "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
216 offset, squashfs_i(inode)->start, block, offset);
217 break;
218 }
219 case SQUASHFS_DIR_TYPE: {
220 struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
221
222 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
223 sizeof(*sqsh_ino));
224 if (err < 0)
225 goto failed_read;
226
227 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
228 inode->i_size = le16_to_cpu(sqsh_ino->file_size);
229 inode->i_op = &squashfs_dir_inode_ops;
230 inode->i_fop = &squashfs_dir_ops;
231 inode->i_mode |= S_IFDIR;
232 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
233 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
234 squashfs_i(inode)->dir_idx_cnt = 0;
235 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
236
237 TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
238 SQUASHFS_INODE_BLK(ino), offset,
239 squashfs_i(inode)->start,
240 le16_to_cpu(sqsh_ino->offset));
241 break;
242 }
243 case SQUASHFS_LDIR_TYPE: {
244 struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
245
246 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
247 sizeof(*sqsh_ino));
248 if (err < 0)
249 goto failed_read;
250
251 xattr_id = le32_to_cpu(sqsh_ino->xattr);
252 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
253 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
254 inode->i_op = &squashfs_dir_inode_ops;
255 inode->i_fop = &squashfs_dir_ops;
256 inode->i_mode |= S_IFDIR;
257 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
258 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
259 squashfs_i(inode)->dir_idx_start = block;
260 squashfs_i(inode)->dir_idx_offset = offset;
261 squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
262 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
263
264 TRACE("Long directory inode %x:%x, start_block %llx, offset "
265 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
266 squashfs_i(inode)->start,
267 le16_to_cpu(sqsh_ino->offset));
268 break;
269 }
270 case SQUASHFS_SYMLINK_TYPE:
271 case SQUASHFS_LSYMLINK_TYPE: {
272 struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
273
274 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
275 sizeof(*sqsh_ino));
276 if (err < 0)
277 goto failed_read;
278
279 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
280 inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
281 inode->i_op = &squashfs_symlink_inode_ops;
282 inode_nohighmem(inode);
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 if (type == SQUASHFS_LSYMLINK_TYPE) {
289 __le32 xattr;
290
291 err = squashfs_read_metadata(sb, NULL, &block,
292 &offset, inode->i_size);
293 if (err < 0)
294 goto failed_read;
295 err = squashfs_read_metadata(sb, &xattr, &block,
296 &offset, sizeof(xattr));
297 if (err < 0)
298 goto failed_read;
299 xattr_id = le32_to_cpu(xattr);
300 }
301
302 TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
303 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
304 block, offset);
305 break;
306 }
307 case SQUASHFS_BLKDEV_TYPE:
308 case SQUASHFS_CHRDEV_TYPE: {
309 struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
310 unsigned int rdev;
311
312 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
313 sizeof(*sqsh_ino));
314 if (err < 0)
315 goto failed_read;
316
317 if (type == SQUASHFS_CHRDEV_TYPE)
318 inode->i_mode |= S_IFCHR;
319 else
320 inode->i_mode |= S_IFBLK;
321 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
322 rdev = le32_to_cpu(sqsh_ino->rdev);
323 init_special_inode(inode, inode->i_mode, new_decode_dev(dev: rdev));
324
325 TRACE("Device inode %x:%x, rdev %x\n",
326 SQUASHFS_INODE_BLK(ino), offset, rdev);
327 break;
328 }
329 case SQUASHFS_LBLKDEV_TYPE:
330 case SQUASHFS_LCHRDEV_TYPE: {
331 struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
332 unsigned int rdev;
333
334 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
335 sizeof(*sqsh_ino));
336 if (err < 0)
337 goto failed_read;
338
339 if (type == SQUASHFS_LCHRDEV_TYPE)
340 inode->i_mode |= S_IFCHR;
341 else
342 inode->i_mode |= S_IFBLK;
343 xattr_id = le32_to_cpu(sqsh_ino->xattr);
344 inode->i_op = &squashfs_inode_ops;
345 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
346 rdev = le32_to_cpu(sqsh_ino->rdev);
347 init_special_inode(inode, inode->i_mode, new_decode_dev(dev: rdev));
348
349 TRACE("Device inode %x:%x, rdev %x\n",
350 SQUASHFS_INODE_BLK(ino), offset, rdev);
351 break;
352 }
353 case SQUASHFS_FIFO_TYPE:
354 case SQUASHFS_SOCKET_TYPE: {
355 struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
356
357 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
358 sizeof(*sqsh_ino));
359 if (err < 0)
360 goto failed_read;
361
362 if (type == SQUASHFS_FIFO_TYPE)
363 inode->i_mode |= S_IFIFO;
364 else
365 inode->i_mode |= S_IFSOCK;
366 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
367 init_special_inode(inode, inode->i_mode, 0);
368 break;
369 }
370 case SQUASHFS_LFIFO_TYPE:
371 case SQUASHFS_LSOCKET_TYPE: {
372 struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;
373
374 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
375 sizeof(*sqsh_ino));
376 if (err < 0)
377 goto failed_read;
378
379 if (type == SQUASHFS_LFIFO_TYPE)
380 inode->i_mode |= S_IFIFO;
381 else
382 inode->i_mode |= S_IFSOCK;
383 xattr_id = le32_to_cpu(sqsh_ino->xattr);
384 inode->i_op = &squashfs_inode_ops;
385 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
386 init_special_inode(inode, inode->i_mode, 0);
387 break;
388 }
389 default:
390 ERROR("Unknown inode type %d in squashfs_iget!\n", type);
391 return -EINVAL;
392 }
393
394 if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
395 err = squashfs_xattr_lookup(sb, xattr_id,
396 &squashfs_i(inode)->xattr_count,
397 &squashfs_i(inode)->xattr_size,
398 &squashfs_i(inode)->xattr);
399 if (err < 0)
400 goto failed_read;
401 inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
402 + 1;
403 } else
404 squashfs_i(inode)->xattr_count = 0;
405
406 return 0;
407
408failed_read:
409 ERROR("Unable to read inode 0x%llx\n", ino);
410 return err;
411}
412
413
414const struct inode_operations squashfs_inode_ops = {
415 .listxattr = squashfs_listxattr
416};
417
418

source code of linux/fs/squashfs/inode.c