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inode.c
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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 <[email protected]>
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/xattr.h>
44 
45 #include "squashfs_fs.h"
46 #include "squashfs_fs_sb.h"
47 #include "squashfs_fs_i.h"
48 #include "squashfs.h"
49 #include "xattr.h"
50 
51 /*
52  * Initialise VFS inode with the base inode information common to all
53  * Squashfs inode types. Sqsh_ino contains the unswapped base inode
54  * off disk.
55  */
56 static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
57  struct squashfs_base_inode *sqsh_ino)
58 {
59  uid_t i_uid;
60  gid_t i_gid;
61  int err;
62 
63  err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &i_uid);
64  if (err)
65  return err;
66 
67  err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &i_gid);
68  if (err)
69  return err;
70 
71  i_uid_write(inode, i_uid);
72  i_gid_write(inode, i_gid);
73  inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
74  inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime);
75  inode->i_atime.tv_sec = inode->i_mtime.tv_sec;
76  inode->i_ctime.tv_sec = inode->i_mtime.tv_sec;
77  inode->i_mode = le16_to_cpu(sqsh_ino->mode);
78  inode->i_size = 0;
79 
80  return err;
81 }
82 
83 
84 struct inode *squashfs_iget(struct super_block *sb, long long ino,
85  unsigned int ino_number)
86 {
87  struct inode *inode = iget_locked(sb, ino_number);
88  int err;
89 
90  TRACE("Entered squashfs_iget\n");
91 
92  if (!inode)
93  return ERR_PTR(-ENOMEM);
94  if (!(inode->i_state & I_NEW))
95  return inode;
96 
97  err = squashfs_read_inode(inode, ino);
98  if (err) {
99  iget_failed(inode);
100  return ERR_PTR(err);
101  }
102 
103  unlock_new_inode(inode);
104  return inode;
105 }
106 
107 
108 /*
109  * Initialise VFS inode by reading inode from inode table (compressed
110  * metadata). The format and amount of data read depends on type.
111  */
112 int squashfs_read_inode(struct inode *inode, long long ino)
113 {
114  struct super_block *sb = inode->i_sb;
115  struct squashfs_sb_info *msblk = sb->s_fs_info;
116  u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
117  int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
118  union squashfs_inode squashfs_ino;
119  struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
120  int xattr_id = SQUASHFS_INVALID_XATTR;
121 
122  TRACE("Entered squashfs_read_inode\n");
123 
124  /*
125  * Read inode base common to all inode types.
126  */
127  err = squashfs_read_metadata(sb, sqshb_ino, &block,
128  &offset, sizeof(*sqshb_ino));
129  if (err < 0)
130  goto failed_read;
131 
132  err = squashfs_new_inode(sb, inode, sqshb_ino);
133  if (err)
134  goto failed_read;
135 
136  block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
137  offset = SQUASHFS_INODE_OFFSET(ino);
138 
139  type = le16_to_cpu(sqshb_ino->inode_type);
140  switch (type) {
141  case SQUASHFS_REG_TYPE: {
142  unsigned int frag_offset, frag;
143  int frag_size;
144  u64 frag_blk;
145  struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
146 
147  err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
148  sizeof(*sqsh_ino));
149  if (err < 0)
150  goto failed_read;
151 
152  frag = le32_to_cpu(sqsh_ino->fragment);
153  if (frag != SQUASHFS_INVALID_FRAG) {
154  frag_offset = le32_to_cpu(sqsh_ino->offset);
155  frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
156  if (frag_size < 0) {
157  err = frag_size;
158  goto failed_read;
159  }
160  } else {
161  frag_blk = SQUASHFS_INVALID_BLK;
162  frag_size = 0;
163  frag_offset = 0;
164  }
165 
166  set_nlink(inode, 1);
167  inode->i_size = le32_to_cpu(sqsh_ino->file_size);
168  inode->i_fop = &generic_ro_fops;
169  inode->i_mode |= S_IFREG;
170  inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
171  squashfs_i(inode)->fragment_block = frag_blk;
172  squashfs_i(inode)->fragment_size = frag_size;
173  squashfs_i(inode)->fragment_offset = frag_offset;
174  squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
175  squashfs_i(inode)->block_list_start = block;
176  squashfs_i(inode)->offset = offset;
177  inode->i_data.a_ops = &squashfs_aops;
178 
179  TRACE("File inode %x:%x, start_block %llx, block_list_start "
180  "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
181  offset, squashfs_i(inode)->start, block, offset);
182  break;
183  }
184  case SQUASHFS_LREG_TYPE: {
185  unsigned int frag_offset, frag;
186  int frag_size;
187  u64 frag_blk;
188  struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
189 
190  err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
191  sizeof(*sqsh_ino));
192  if (err < 0)
193  goto failed_read;
194 
195  frag = le32_to_cpu(sqsh_ino->fragment);
196  if (frag != SQUASHFS_INVALID_FRAG) {
197  frag_offset = le32_to_cpu(sqsh_ino->offset);
198  frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
199  if (frag_size < 0) {
200  err = frag_size;
201  goto failed_read;
202  }
203  } else {
204  frag_blk = SQUASHFS_INVALID_BLK;
205  frag_size = 0;
206  frag_offset = 0;
207  }
208 
209  xattr_id = le32_to_cpu(sqsh_ino->xattr);
210  set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
211  inode->i_size = le64_to_cpu(sqsh_ino->file_size);
212  inode->i_op = &squashfs_inode_ops;
213  inode->i_fop = &generic_ro_fops;
214  inode->i_mode |= S_IFREG;
215  inode->i_blocks = (inode->i_size -
216  le64_to_cpu(sqsh_ino->sparse) + 511) >> 9;
217 
218  squashfs_i(inode)->fragment_block = frag_blk;
219  squashfs_i(inode)->fragment_size = frag_size;
220  squashfs_i(inode)->fragment_offset = frag_offset;
221  squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
222  squashfs_i(inode)->block_list_start = block;
223  squashfs_i(inode)->offset = offset;
224  inode->i_data.a_ops = &squashfs_aops;
225 
226  TRACE("File inode %x:%x, start_block %llx, block_list_start "
227  "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
228  offset, squashfs_i(inode)->start, block, offset);
229  break;
230  }
231  case SQUASHFS_DIR_TYPE: {
232  struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
233 
234  err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
235  sizeof(*sqsh_ino));
236  if (err < 0)
237  goto failed_read;
238 
239  set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
240  inode->i_size = le16_to_cpu(sqsh_ino->file_size);
241  inode->i_op = &squashfs_dir_inode_ops;
242  inode->i_fop = &squashfs_dir_ops;
243  inode->i_mode |= S_IFDIR;
244  squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
245  squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
246  squashfs_i(inode)->dir_idx_cnt = 0;
247  squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
248 
249  TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
250  SQUASHFS_INODE_BLK(ino), offset,
251  squashfs_i(inode)->start,
252  le16_to_cpu(sqsh_ino->offset));
253  break;
254  }
255  case SQUASHFS_LDIR_TYPE: {
256  struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
257 
258  err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
259  sizeof(*sqsh_ino));
260  if (err < 0)
261  goto failed_read;
262 
263  xattr_id = le32_to_cpu(sqsh_ino->xattr);
264  set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
265  inode->i_size = le32_to_cpu(sqsh_ino->file_size);
266  inode->i_op = &squashfs_dir_inode_ops;
267  inode->i_fop = &squashfs_dir_ops;
268  inode->i_mode |= S_IFDIR;
269  squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
270  squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
271  squashfs_i(inode)->dir_idx_start = block;
272  squashfs_i(inode)->dir_idx_offset = offset;
273  squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
274  squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
275 
276  TRACE("Long directory inode %x:%x, start_block %llx, offset "
277  "%x\n", SQUASHFS_INODE_BLK(ino), offset,
278  squashfs_i(inode)->start,
279  le16_to_cpu(sqsh_ino->offset));
280  break;
281  }
282  case SQUASHFS_SYMLINK_TYPE:
283  case SQUASHFS_LSYMLINK_TYPE: {
284  struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
285 
286  err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
287  sizeof(*sqsh_ino));
288  if (err < 0)
289  goto failed_read;
290 
291  set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
292  inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
293  inode->i_op = &squashfs_symlink_inode_ops;
294  inode->i_data.a_ops = &squashfs_symlink_aops;
295  inode->i_mode |= S_IFLNK;
296  squashfs_i(inode)->start = block;
297  squashfs_i(inode)->offset = offset;
298 
299  if (type == SQUASHFS_LSYMLINK_TYPE) {
300  __le32 xattr;
301 
302  err = squashfs_read_metadata(sb, NULL, &block,
303  &offset, inode->i_size);
304  if (err < 0)
305  goto failed_read;
306  err = squashfs_read_metadata(sb, &xattr, &block,
307  &offset, sizeof(xattr));
308  if (err < 0)
309  goto failed_read;
310  xattr_id = le32_to_cpu(xattr);
311  }
312 
313  TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
314  "%x\n", SQUASHFS_INODE_BLK(ino), offset,
315  block, offset);
316  break;
317  }
318  case SQUASHFS_BLKDEV_TYPE:
319  case SQUASHFS_CHRDEV_TYPE: {
320  struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
321  unsigned int rdev;
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_CHRDEV_TYPE)
329  inode->i_mode |= S_IFCHR;
330  else
331  inode->i_mode |= S_IFBLK;
332  set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
333  rdev = le32_to_cpu(sqsh_ino->rdev);
334  init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
335 
336  TRACE("Device inode %x:%x, rdev %x\n",
337  SQUASHFS_INODE_BLK(ino), offset, rdev);
338  break;
339  }
340  case SQUASHFS_LBLKDEV_TYPE:
341  case SQUASHFS_LCHRDEV_TYPE: {
342  struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
343  unsigned int rdev;
344 
345  err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
346  sizeof(*sqsh_ino));
347  if (err < 0)
348  goto failed_read;
349 
350  if (type == SQUASHFS_LCHRDEV_TYPE)
351  inode->i_mode |= S_IFCHR;
352  else
353  inode->i_mode |= S_IFBLK;
354  xattr_id = le32_to_cpu(sqsh_ino->xattr);
355  inode->i_op = &squashfs_inode_ops;
356  set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
357  rdev = le32_to_cpu(sqsh_ino->rdev);
358  init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
359 
360  TRACE("Device inode %x:%x, rdev %x\n",
361  SQUASHFS_INODE_BLK(ino), offset, rdev);
362  break;
363  }
364  case SQUASHFS_FIFO_TYPE:
365  case SQUASHFS_SOCKET_TYPE: {
366  struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
367 
368  err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
369  sizeof(*sqsh_ino));
370  if (err < 0)
371  goto failed_read;
372 
373  if (type == SQUASHFS_FIFO_TYPE)
374  inode->i_mode |= S_IFIFO;
375  else
376  inode->i_mode |= S_IFSOCK;
377  set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
378  init_special_inode(inode, inode->i_mode, 0);
379  break;
380  }
381  case SQUASHFS_LFIFO_TYPE:
382  case SQUASHFS_LSOCKET_TYPE: {
383  struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;
384 
385  err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
386  sizeof(*sqsh_ino));
387  if (err < 0)
388  goto failed_read;
389 
390  if (type == SQUASHFS_LFIFO_TYPE)
391  inode->i_mode |= S_IFIFO;
392  else
393  inode->i_mode |= S_IFSOCK;
394  xattr_id = le32_to_cpu(sqsh_ino->xattr);
395  inode->i_op = &squashfs_inode_ops;
396  set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
397  init_special_inode(inode, inode->i_mode, 0);
398  break;
399  }
400  default:
401  ERROR("Unknown inode type %d in squashfs_iget!\n", type);
402  return -EINVAL;
403  }
404 
405  if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
406  err = squashfs_xattr_lookup(sb, xattr_id,
407  &squashfs_i(inode)->xattr_count,
408  &squashfs_i(inode)->xattr_size,
409  &squashfs_i(inode)->xattr);
410  if (err < 0)
411  goto failed_read;
412  inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
413  + 1;
414  } else
415  squashfs_i(inode)->xattr_count = 0;
416 
417  return 0;
418 
419 failed_read:
420  ERROR("Unable to read inode 0x%llx\n", ino);
421  return err;
422 }
423 
424 
425 const struct inode_operations squashfs_inode_ops = {
426  .getxattr = generic_getxattr,
427  .listxattr = squashfs_listxattr
428 };
429 
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