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