fs/squashfs/inode.c

   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/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
  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         int xattr_id = SQUASHFS_INVALID_XATTR;
 116
 117         TRACE("Entered squashfs_read_inode\n");
 118
 119         /*
 120          * Read inode base common to all inode types.
 121          */
 122         err = squashfs_read_metadata(sb, sqshb_ino, &block,
 123                                 &offset, sizeof(*sqshb_ino));
 124         if (err < 0)
 125                 goto failed_read;
 126
 127         err = squashfs_new_inode(sb, inode, sqshb_ino);
 128         if (err)
 129                 goto failed_read;
 130
 131         block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
 132         offset = SQUASHFS_INODE_OFFSET(ino);
 133
 134         type = le16_to_cpu(sqshb_ino->inode_type);
 135         switch (type) {
 136         case SQUASHFS_REG_TYPE: {
 137                 unsigned int frag_offset, frag;
 138                 int frag_size;
 139                 u64 frag_blk;
 140                 struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
 141
 142                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 143                                                         sizeof(*sqsh_ino));
 144                 if (err < 0)
 145                         goto failed_read;
 146
 147                 frag = le32_to_cpu(sqsh_ino->fragment);
 148                 if (frag != SQUASHFS_INVALID_FRAG) {
 149                         frag_offset = le32_to_cpu(sqsh_ino->offset);
 150                         frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
 151                         if (frag_size < 0) {
 152                                 err = frag_size;
 153                                 goto failed_read;
 154                         }
 155                 } else {
 156                         frag_blk = SQUASHFS_INVALID_BLK;
 157                         frag_size = 0;
 158                         frag_offset = 0;
 159                 }
 160
 161                 inode->i_nlink = 1;
 162                 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
 163                 inode->i_fop = &generic_ro_fops;
 164                 inode->i_mode |= S_IFREG;
 165                 inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
 166                 squashfs_i(inode)->fragment_block = frag_blk;
 167                 squashfs_i(inode)->fragment_size = frag_size;
 168                 squashfs_i(inode)->fragment_offset = frag_offset;
 169                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 170                 squashfs_i(inode)->block_list_start = block;
 171                 squashfs_i(inode)->offset = offset;
 172                 inode->i_data.a_ops = &squashfs_aops;
 173
 174                 TRACE("File inode %x:%x, start_block %llx, block_list_start "
 175                         "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
 176                         offset, squashfs_i(inode)->start, block, offset);
 177                 break;
 178         }
 179         case SQUASHFS_LREG_TYPE: {
 180                 unsigned int frag_offset, frag;
 181                 int frag_size;
 182                 u64 frag_blk;
 183                 struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
 184
 185                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 186                                                         sizeof(*sqsh_ino));
 187                 if (err < 0)
 188                         goto failed_read;
 189
 190                 frag = le32_to_cpu(sqsh_ino->fragment);
 191                 if (frag != SQUASHFS_INVALID_FRAG) {
 192                         frag_offset = le32_to_cpu(sqsh_ino->offset);
 193                         frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
 194                         if (frag_size < 0) {
 195                                 err = frag_size;
 196                                 goto failed_read;
 197                         }
 198                 } else {
 199                         frag_blk = SQUASHFS_INVALID_BLK;
 200                         frag_size = 0;
 201                         frag_offset = 0;
 202                 }
 203
 204                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 205                 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
 206                 inode->i_size = le64_to_cpu(sqsh_ino->file_size);
 207                 inode->i_op = &squashfs_inode_ops;
 208                 inode->i_fop = &generic_ro_fops;
 209                 inode->i_mode |= S_IFREG;
 210                 inode->i_blocks = ((inode->i_size -
 211                                 le64_to_cpu(sqsh_ino->sparse) - 1) >> 9) + 1;
 212
 213                 squashfs_i(inode)->fragment_block = frag_blk;
 214                 squashfs_i(inode)->fragment_size = frag_size;
 215                 squashfs_i(inode)->fragment_offset = frag_offset;
 216                 squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
 217                 squashfs_i(inode)->block_list_start = block;
 218                 squashfs_i(inode)->offset = offset;
 219                 inode->i_data.a_ops = &squashfs_aops;
 220
 221                 TRACE("File inode %x:%x, start_block %llx, block_list_start "
 222                         "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
 223                         offset, squashfs_i(inode)->start, block, offset);
 224                 break;
 225         }
 226         case SQUASHFS_DIR_TYPE: {
 227                 struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
 228
 229                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 230                                 sizeof(*sqsh_ino));
 231                 if (err < 0)
 232                         goto failed_read;
 233
 234                 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
 235                 inode->i_size = le16_to_cpu(sqsh_ino->file_size);
 236                 inode->i_op = &squashfs_dir_inode_ops;
 237                 inode->i_fop = &squashfs_dir_ops;
 238                 inode->i_mode |= S_IFDIR;
 239                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 240                 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
 241                 squashfs_i(inode)->dir_idx_cnt = 0;
 242                 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
 243
 244                 TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
 245                                 SQUASHFS_INODE_BLK(ino), offset,
 246                                 squashfs_i(inode)->start,
 247                                 le16_to_cpu(sqsh_ino->offset));
 248                 break;
 249         }
 250         case SQUASHFS_LDIR_TYPE: {
 251                 struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
 252
 253                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 254                                 sizeof(*sqsh_ino));
 255                 if (err < 0)
 256                         goto failed_read;
 257
 258                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 259                 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
 260                 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
 261                 inode->i_op = &squashfs_dir_inode_ops;
 262                 inode->i_fop = &squashfs_dir_ops;
 263                 inode->i_mode |= S_IFDIR;
 264                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 265                 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
 266                 squashfs_i(inode)->dir_idx_start = block;
 267                 squashfs_i(inode)->dir_idx_offset = offset;
 268                 squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
 269                 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
 270
 271                 TRACE("Long directory inode %x:%x, start_block %llx, offset "
 272                                 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
 273                                 squashfs_i(inode)->start,
 274                                 le16_to_cpu(sqsh_ino->offset));
 275                 break;
 276         }
 277         case SQUASHFS_SYMLINK_TYPE:
 278         case SQUASHFS_LSYMLINK_TYPE: {
 279                 struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
 280
 281                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 282                                 sizeof(*sqsh_ino));
 283                 if (err < 0)
 284                         goto failed_read;
 285
 286                 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
 287                 inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
 288                 inode->i_op = &squashfs_symlink_inode_ops;
 289                 inode->i_data.a_ops = &squashfs_symlink_aops;
 290                 inode->i_mode |= S_IFLNK;
 291                 squashfs_i(inode)->start = block;
 292                 squashfs_i(inode)->offset = offset;
 293
 294                 if (type == SQUASHFS_LSYMLINK_TYPE) {
 295                         __le32 xattr;
 296
 297                         err = squashfs_read_metadata(sb, NULL, &block,
 298                                                 &offset, inode->i_size);
 299                         if (err < 0)
 300                                 goto failed_read;
 301                         err = squashfs_read_metadata(sb, &xattr, &block,
 302                                                 &offset, sizeof(xattr));
 303                         if (err < 0)
 304                                 goto failed_read;
 305                         xattr_id = le32_to_cpu(xattr);
 306                 }
 307
 308                 TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
 309                                 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
 310                                 block, offset);
 311                 break;
 312         }
 313         case SQUASHFS_BLKDEV_TYPE:
 314         case SQUASHFS_CHRDEV_TYPE: {
 315                 struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
 316                 unsigned int rdev;
 317
 318                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 319                                 sizeof(*sqsh_ino));
 320                 if (err < 0)
 321                         goto failed_read;
 322
 323                 if (type == SQUASHFS_CHRDEV_TYPE)
 324                         inode->i_mode |= S_IFCHR;
 325                 else
 326                         inode->i_mode |= S_IFBLK;
 327                 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
 328                 rdev = le32_to_cpu(sqsh_ino->rdev);
 329                 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
 330
 331                 TRACE("Device inode %x:%x, rdev %x\n",
 332                                 SQUASHFS_INODE_BLK(ino), offset, rdev);
 333                 break;
 334         }
 335         case SQUASHFS_LBLKDEV_TYPE:
 336         case SQUASHFS_LCHRDEV_TYPE: {
 337                 struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
 338                 unsigned int rdev;
 339
 340                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 341                                 sizeof(*sqsh_ino));
 342                 if (err < 0)
 343                         goto failed_read;
 344
 345                 if (type == SQUASHFS_LCHRDEV_TYPE)
 346                         inode->i_mode |= S_IFCHR;
 347                 else
 348                         inode->i_mode |= S_IFBLK;
 349                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 350                 inode->i_op = &squashfs_inode_ops;
 351                 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
 352                 rdev = le32_to_cpu(sqsh_ino->rdev);
 353                 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
 354
 355                 TRACE("Device inode %x:%x, rdev %x\n",
 356                                 SQUASHFS_INODE_BLK(ino), offset, rdev);
 357                 break;
 358         }
 359         case SQUASHFS_FIFO_TYPE:
 360         case SQUASHFS_SOCKET_TYPE: {
 361                 struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
 362
 363                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 364                                 sizeof(*sqsh_ino));
 365                 if (err < 0)
 366                         goto failed_read;
 367
 368                 if (type == SQUASHFS_FIFO_TYPE)
 369                         inode->i_mode |= S_IFIFO;
 370                 else
 371                         inode->i_mode |= S_IFSOCK;
 372                 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
 373                 init_special_inode(inode, inode->i_mode, 0);
 374                 break;
 375         }
 376         case SQUASHFS_LFIFO_TYPE:
 377         case SQUASHFS_LSOCKET_TYPE: {
 378                 struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;
 379
 380                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 381                                 sizeof(*sqsh_ino));
 382                 if (err < 0)
 383                         goto failed_read;
 384
 385                 if (type == SQUASHFS_LFIFO_TYPE)
 386                         inode->i_mode |= S_IFIFO;
 387                 else
 388                         inode->i_mode |= S_IFSOCK;
 389                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 390                 inode->i_op = &squashfs_inode_ops;
 391                 inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
 392                 init_special_inode(inode, inode->i_mode, 0);
 393                 break;
 394         }
 395         default:
 396                 ERROR("Unknown inode type %d in squashfs_iget!\n", type);
 397                 return -EINVAL;
 398         }
 399
 400         if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
 401                 err = squashfs_xattr_lookup(sb, xattr_id,
 402                                         &squashfs_i(inode)->xattr_count,
 403                                         &squashfs_i(inode)->xattr_size,
 404                                         &squashfs_i(inode)->xattr);
 405                 if (err < 0)
 406                         goto failed_read;
 407                 inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
 408                                 + 1;
 409         } else
 410                 squashfs_i(inode)->xattr_count = 0;
 411
 412         return 0;
 413
 414 failed_read:
 415         ERROR("Unable to read inode 0x%llx\n", ino);
 416         return err;
 417 }
 418
 419
 420 const struct inode_operations squashfs_inode_ops = {
 421         .getxattr = generic_getxattr,
 422         .listxattr = squashfs_listxattr
 423 };
 424