linux/fs/squashfs/inode.c
<<
>>
Prefs
   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 */
  56static 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
  84struct 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 */
 112int 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
 419failed_read:
 420        ERROR("Unable to read inode 0x%llx\n", ino);
 421        return err;
 422}
 423
 424
 425const struct inode_operations squashfs_inode_ops = {
 426        .getxattr = generic_getxattr,
 427        .listxattr = squashfs_listxattr
 428};
 429
 430
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.