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TOMOYO Linux Cross Reference
Linux/fs/squashfs/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 <phillip@squashfs.org.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/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 
430 

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