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@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