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 #include <linux/pagemap.h>
  45
  46 #include "squashfs_fs.h"
  47 #include "squashfs_fs_sb.h"
  48 #include "squashfs_fs_i.h"
  49 #include "squashfs.h"
  50 #include "xattr.h"
  51
  52 /*
  53  * Initialise VFS inode with the base inode information common to all
  54  * Squashfs inode types.  Sqsh_ino contains the unswapped base inode
  55  * off disk.
  56  */
  57 static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
  58                                 struct squashfs_base_inode *sqsh_ino)
  59 {
  60         uid_t i_uid;
  61         gid_t i_gid;
  62         int err;
  63
  64         err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &i_uid);
  65         if (err)
  66                 return err;
  67
  68         err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &i_gid);
  69         if (err)
  70                 return err;
  71
  72         i_uid_write(inode, i_uid);
  73         i_gid_write(inode, i_gid);
  74         inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
  75         inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime);
  76         inode->i_atime.tv_sec = inode->i_mtime.tv_sec;
  77         inode->i_ctime.tv_sec = inode->i_mtime.tv_sec;
  78         inode->i_mode = le16_to_cpu(sqsh_ino->mode);
  79         inode->i_size = 0;
  80
  81         return err;
  82 }
  83
  84
  85 struct inode *squashfs_iget(struct super_block *sb, long long ino,
  86                                 unsigned int ino_number)
  87 {
  88         struct inode *inode = iget_locked(sb, ino_number);
  89         int err;
  90
  91         TRACE("Entered squashfs_iget\n");
  92
  93         if (!inode)
  94                 return ERR_PTR(-ENOMEM);
  95         if (!(inode->i_state & I_NEW))
  96                 return inode;
  97
  98         err = squashfs_read_inode(inode, ino);
  99         if (err) {
 100                 iget_failed(inode);
 101                 return ERR_PTR(err);
 102         }
 103
 104         unlock_new_inode(inode);
 105         return inode;
 106 }
 107
 108
 109 /*
 110  * Initialise VFS inode by reading inode from inode table (compressed
 111  * metadata).  The format and amount of data read depends on type.
 112  */
 113 int squashfs_read_inode(struct inode *inode, long long ino)
 114 {
 115         struct super_block *sb = inode->i_sb;
 116         struct squashfs_sb_info *msblk = sb->s_fs_info;
 117         u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
 118         int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
 119         union squashfs_inode squashfs_ino;
 120         struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
 121         int xattr_id = SQUASHFS_INVALID_XATTR;
 122
 123         TRACE("Entered squashfs_read_inode\n");
 124
 125         /*
 126          * Read inode base common to all inode types.
 127          */
 128         err = squashfs_read_metadata(sb, sqshb_ino, &block,
 129                                 &offset, sizeof(*sqshb_ino));
 130         if (err < 0)
 131                 goto failed_read;
 132
 133         err = squashfs_new_inode(sb, inode, sqshb_ino);
 134         if (err)
 135                 goto failed_read;
 136
 137         block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
 138         offset = SQUASHFS_INODE_OFFSET(ino);
 139
 140         type = le16_to_cpu(sqshb_ino->inode_type);
 141         switch (type) {
 142         case SQUASHFS_REG_TYPE: {
 143                 unsigned int frag_offset, frag;
 144                 int frag_size;
 145                 u64 frag_blk;
 146                 struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
 147
 148                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 149                                                         sizeof(*sqsh_ino));
 150                 if (err < 0)
 151                         goto failed_read;
 152
 153                 frag = le32_to_cpu(sqsh_ino->fragment);
 154                 if (frag != SQUASHFS_INVALID_FRAG) {
 155                         frag_offset = le32_to_cpu(sqsh_ino->offset);
 156                         frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
 157                         if (frag_size < 0) {
 158                                 err = frag_size;
 159                                 goto failed_read;
 160                         }
 161                 } else {
 162                         frag_blk = SQUASHFS_INVALID_BLK;
 163                         frag_size = 0;
 164                         frag_offset = 0;
 165                 }
 166
 167                 set_nlink(inode, 1);
 168                 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
 169                 inode->i_fop = &generic_ro_fops;
 170                 inode->i_mode |= S_IFREG;
 171                 inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
 172                 squashfs_i(inode)->fragment_block = frag_blk;
 173                 squashfs_i(inode)->fragment_size = frag_size;
 174                 squashfs_i(inode)->fragment_offset = frag_offset;
 175                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 176                 squashfs_i(inode)->block_list_start = block;
 177                 squashfs_i(inode)->offset = offset;
 178                 inode->i_data.a_ops = &squashfs_aops;
 179
 180                 TRACE("File inode %x:%x, start_block %llx, block_list_start "
 181                         "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
 182                         offset, squashfs_i(inode)->start, block, offset);
 183                 break;
 184         }
 185         case SQUASHFS_LREG_TYPE: {
 186                 unsigned int frag_offset, frag;
 187                 int frag_size;
 188                 u64 frag_blk;
 189                 struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
 190
 191                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 192                                                         sizeof(*sqsh_ino));
 193                 if (err < 0)
 194                         goto failed_read;
 195
 196                 frag = le32_to_cpu(sqsh_ino->fragment);
 197                 if (frag != SQUASHFS_INVALID_FRAG) {
 198                         frag_offset = le32_to_cpu(sqsh_ino->offset);
 199                         frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
 200                         if (frag_size < 0) {
 201                                 err = frag_size;
 202                                 goto failed_read;
 203                         }
 204                 } else {
 205                         frag_blk = SQUASHFS_INVALID_BLK;
 206                         frag_size = 0;
 207                         frag_offset = 0;
 208                 }
 209
 210                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 211                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 212                 inode->i_size = le64_to_cpu(sqsh_ino->file_size);
 213                 inode->i_op = &squashfs_inode_ops;
 214                 inode->i_fop = &generic_ro_fops;
 215                 inode->i_mode |= S_IFREG;
 216                 inode->i_blocks = (inode->i_size -
 217                                 le64_to_cpu(sqsh_ino->sparse) + 511) >> 9;
 218
 219                 squashfs_i(inode)->fragment_block = frag_blk;
 220                 squashfs_i(inode)->fragment_size = frag_size;
 221                 squashfs_i(inode)->fragment_offset = frag_offset;
 222                 squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
 223                 squashfs_i(inode)->block_list_start = block;
 224                 squashfs_i(inode)->offset = offset;
 225                 inode->i_data.a_ops = &squashfs_aops;
 226
 227                 TRACE("File inode %x:%x, start_block %llx, block_list_start "
 228                         "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
 229                         offset, squashfs_i(inode)->start, block, offset);
 230                 break;
 231         }
 232         case SQUASHFS_DIR_TYPE: {
 233                 struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
 234
 235                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 236                                 sizeof(*sqsh_ino));
 237                 if (err < 0)
 238                         goto failed_read;
 239
 240                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 241                 inode->i_size = le16_to_cpu(sqsh_ino->file_size);
 242                 inode->i_op = &squashfs_dir_inode_ops;
 243                 inode->i_fop = &squashfs_dir_ops;
 244                 inode->i_mode |= S_IFDIR;
 245                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 246                 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
 247                 squashfs_i(inode)->dir_idx_cnt = 0;
 248                 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
 249
 250                 TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
 251                                 SQUASHFS_INODE_BLK(ino), offset,
 252                                 squashfs_i(inode)->start,
 253                                 le16_to_cpu(sqsh_ino->offset));
 254                 break;
 255         }
 256         case SQUASHFS_LDIR_TYPE: {
 257                 struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
 258
 259                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 260                                 sizeof(*sqsh_ino));
 261                 if (err < 0)
 262                         goto failed_read;
 263
 264                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 265                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 266                 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
 267                 inode->i_op = &squashfs_dir_inode_ops;
 268                 inode->i_fop = &squashfs_dir_ops;
 269                 inode->i_mode |= S_IFDIR;
 270                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 271                 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
 272                 squashfs_i(inode)->dir_idx_start = block;
 273                 squashfs_i(inode)->dir_idx_offset = offset;
 274                 squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
 275                 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
 276
 277                 TRACE("Long directory inode %x:%x, start_block %llx, offset "
 278                                 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
 279                                 squashfs_i(inode)->start,
 280                                 le16_to_cpu(sqsh_ino->offset));
 281                 break;
 282         }
 283         case SQUASHFS_SYMLINK_TYPE:
 284         case SQUASHFS_LSYMLINK_TYPE: {
 285                 struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
 286
 287                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 288                                 sizeof(*sqsh_ino));
 289                 if (err < 0)
 290                         goto failed_read;
 291
 292                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 293                 inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
 294                 inode->i_op = &squashfs_symlink_inode_ops;
 295                 inode_nohighmem(inode);
 296                 inode->i_data.a_ops = &squashfs_symlink_aops;
 297                 inode->i_mode |= S_IFLNK;
 298                 squashfs_i(inode)->start = block;
 299                 squashfs_i(inode)->offset = offset;
 300
 301                 if (type == SQUASHFS_LSYMLINK_TYPE) {
 302                         __le32 xattr;
 303
 304                         err = squashfs_read_metadata(sb, NULL, &block,
 305                                                 &offset, inode->i_size);
 306                         if (err < 0)
 307                                 goto failed_read;
 308                         err = squashfs_read_metadata(sb, &xattr, &block,
 309                                                 &offset, sizeof(xattr));
 310                         if (err < 0)
 311                                 goto failed_read;
 312                         xattr_id = le32_to_cpu(xattr);
 313                 }
 314
 315                 TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
 316                                 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
 317                                 block, offset);
 318                 break;
 319         }
 320         case SQUASHFS_BLKDEV_TYPE:
 321         case SQUASHFS_CHRDEV_TYPE: {
 322                 struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
 323                 unsigned int rdev;
 324
 325                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 326                                 sizeof(*sqsh_ino));
 327                 if (err < 0)
 328                         goto failed_read;
 329
 330                 if (type == SQUASHFS_CHRDEV_TYPE)
 331                         inode->i_mode |= S_IFCHR;
 332                 else
 333                         inode->i_mode |= S_IFBLK;
 334                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 335                 rdev = le32_to_cpu(sqsh_ino->rdev);
 336                 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
 337
 338                 TRACE("Device inode %x:%x, rdev %x\n",
 339                                 SQUASHFS_INODE_BLK(ino), offset, rdev);
 340                 break;
 341         }
 342         case SQUASHFS_LBLKDEV_TYPE:
 343         case SQUASHFS_LCHRDEV_TYPE: {
 344                 struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
 345                 unsigned int rdev;
 346
 347                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 348                                 sizeof(*sqsh_ino));
 349                 if (err < 0)
 350                         goto failed_read;
 351
 352                 if (type == SQUASHFS_LCHRDEV_TYPE)
 353                         inode->i_mode |= S_IFCHR;
 354                 else
 355                         inode->i_mode |= S_IFBLK;
 356                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 357                 inode->i_op = &squashfs_inode_ops;
 358                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 359                 rdev = le32_to_cpu(sqsh_ino->rdev);
 360                 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
 361
 362                 TRACE("Device inode %x:%x, rdev %x\n",
 363                                 SQUASHFS_INODE_BLK(ino), offset, rdev);
 364                 break;
 365         }
 366         case SQUASHFS_FIFO_TYPE:
 367         case SQUASHFS_SOCKET_TYPE: {
 368                 struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
 369
 370                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 371                                 sizeof(*sqsh_ino));
 372                 if (err < 0)
 373                         goto failed_read;
 374
 375                 if (type == SQUASHFS_FIFO_TYPE)
 376                         inode->i_mode |= S_IFIFO;
 377                 else
 378                         inode->i_mode |= S_IFSOCK;
 379                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 380                 init_special_inode(inode, inode->i_mode, 0);
 381                 break;
 382         }
 383         case SQUASHFS_LFIFO_TYPE:
 384         case SQUASHFS_LSOCKET_TYPE: {
 385                 struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;
 386
 387                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 388                                 sizeof(*sqsh_ino));
 389                 if (err < 0)
 390                         goto failed_read;
 391
 392                 if (type == SQUASHFS_LFIFO_TYPE)
 393                         inode->i_mode |= S_IFIFO;
 394                 else
 395                         inode->i_mode |= S_IFSOCK;
 396                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 397                 inode->i_op = &squashfs_inode_ops;
 398                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 399                 init_special_inode(inode, inode->i_mode, 0);
 400                 break;
 401         }
 402         default:
 403                 ERROR("Unknown inode type %d in squashfs_iget!\n", type);
 404                 return -EINVAL;
 405         }
 406
 407         if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
 408                 err = squashfs_xattr_lookup(sb, xattr_id,
 409                                         &squashfs_i(inode)->xattr_count,
 410                                         &squashfs_i(inode)->xattr_size,
 411                                         &squashfs_i(inode)->xattr);
 412                 if (err < 0)
 413                         goto failed_read;
 414                 inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
 415                                 + 1;
 416         } else
 417                 squashfs_i(inode)->xattr_count = 0;
 418
 419         return 0;
 420
 421 failed_read:
 422         ERROR("Unable to read inode 0x%llx\n", ino);
 423         return err;
 424 }
 425
 426
 427 const struct inode_operations squashfs_inode_ops = {
 428         .getxattr = generic_getxattr,
 429         .listxattr = squashfs_listxattr
 430 };
 431