LXR linux/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 */
  57static 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
  85struct 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 */
 113int 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
 421failed_read:
 422        ERROR("Unable to read inode 0x%llx\n", ino);
 423        return err;
 424}
 425
 426
 427const struct inode_operations squashfs_inode_ops = {
 428        .getxattr = generic_getxattr,
 429        .listxattr = squashfs_listxattr
 430};
 431
 432