|  | /* | 
|  | * Squashfs - a compressed read only filesystem for Linux | 
|  | * | 
|  | * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008 | 
|  | * Phillip Lougher <phillip@lougher.demon.co.uk> | 
|  | * | 
|  | * This program is free software; you can redistribute it and/or | 
|  | * modify it under the terms of the GNU General Public License | 
|  | * as published by the Free Software Foundation; either version 2, | 
|  | * or (at your option) any later version. | 
|  | * | 
|  | * This program is distributed in the hope that it will be useful, | 
|  | * but WITHOUT ANY WARRANTY; without even the implied warranty of | 
|  | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the | 
|  | * GNU General Public License for more details. | 
|  | * | 
|  | * You should have received a copy of the GNU General Public License | 
|  | * along with this program; if not, write to the Free Software | 
|  | * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | 
|  | * | 
|  | * inode.c | 
|  | */ | 
|  |  | 
|  | /* | 
|  | * This file implements code to create and read inodes from disk. | 
|  | * | 
|  | * Inodes in Squashfs are identified by a 48-bit inode which encodes the | 
|  | * location of the compressed metadata block containing the inode, and the byte | 
|  | * offset into that block where the inode is placed (<block, offset>). | 
|  | * | 
|  | * To maximise compression there are different inodes for each file type | 
|  | * (regular file, directory, device, etc.), the inode contents and length | 
|  | * varying with the type. | 
|  | * | 
|  | * To further maximise compression, two types of regular file inode and | 
|  | * directory inode are defined: inodes optimised for frequently occurring | 
|  | * regular files and directories, and extended types where extra | 
|  | * information has to be stored. | 
|  | */ | 
|  |  | 
|  | #include <linux/fs.h> | 
|  | #include <linux/vfs.h> | 
|  | #include <linux/zlib.h> | 
|  |  | 
|  | #include "squashfs_fs.h" | 
|  | #include "squashfs_fs_sb.h" | 
|  | #include "squashfs_fs_i.h" | 
|  | #include "squashfs.h" | 
|  |  | 
|  | /* | 
|  | * Initialise VFS inode with the base inode information common to all | 
|  | * Squashfs inode types.  Sqsh_ino contains the unswapped base inode | 
|  | * off disk. | 
|  | */ | 
|  | static int squashfs_new_inode(struct super_block *sb, struct inode *inode, | 
|  | struct squashfs_base_inode *sqsh_ino) | 
|  | { | 
|  | int err; | 
|  |  | 
|  | err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &inode->i_uid); | 
|  | if (err) | 
|  | return err; | 
|  |  | 
|  | err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &inode->i_gid); | 
|  | if (err) | 
|  | return err; | 
|  |  | 
|  | inode->i_ino = le32_to_cpu(sqsh_ino->inode_number); | 
|  | inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime); | 
|  | inode->i_atime.tv_sec = inode->i_mtime.tv_sec; | 
|  | inode->i_ctime.tv_sec = inode->i_mtime.tv_sec; | 
|  | inode->i_mode = le16_to_cpu(sqsh_ino->mode); | 
|  | inode->i_size = 0; | 
|  |  | 
|  | return err; | 
|  | } | 
|  |  | 
|  |  | 
|  | struct inode *squashfs_iget(struct super_block *sb, long long ino, | 
|  | unsigned int ino_number) | 
|  | { | 
|  | struct inode *inode = iget_locked(sb, ino_number); | 
|  | int err; | 
|  |  | 
|  | TRACE("Entered squashfs_iget\n"); | 
|  |  | 
|  | if (!inode) | 
|  | return ERR_PTR(-ENOMEM); | 
|  | if (!(inode->i_state & I_NEW)) | 
|  | return inode; | 
|  |  | 
|  | err = squashfs_read_inode(inode, ino); | 
|  | if (err) { | 
|  | iget_failed(inode); | 
|  | return ERR_PTR(err); | 
|  | } | 
|  |  | 
|  | unlock_new_inode(inode); | 
|  | return inode; | 
|  | } | 
|  |  | 
|  |  | 
|  | /* | 
|  | * Initialise VFS inode by reading inode from inode table (compressed | 
|  | * metadata).  The format and amount of data read depends on type. | 
|  | */ | 
|  | int squashfs_read_inode(struct inode *inode, long long ino) | 
|  | { | 
|  | struct super_block *sb = inode->i_sb; | 
|  | struct squashfs_sb_info *msblk = sb->s_fs_info; | 
|  | u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table; | 
|  | int err, type, offset = SQUASHFS_INODE_OFFSET(ino); | 
|  | union squashfs_inode squashfs_ino; | 
|  | struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base; | 
|  |  | 
|  | TRACE("Entered squashfs_read_inode\n"); | 
|  |  | 
|  | /* | 
|  | * Read inode base common to all inode types. | 
|  | */ | 
|  | err = squashfs_read_metadata(sb, sqshb_ino, &block, | 
|  | &offset, sizeof(*sqshb_ino)); | 
|  | if (err < 0) | 
|  | goto failed_read; | 
|  |  | 
|  | err = squashfs_new_inode(sb, inode, sqshb_ino); | 
|  | if (err) | 
|  | goto failed_read; | 
|  |  | 
|  | block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table; | 
|  | offset = SQUASHFS_INODE_OFFSET(ino); | 
|  |  | 
|  | type = le16_to_cpu(sqshb_ino->inode_type); | 
|  | switch (type) { | 
|  | case SQUASHFS_REG_TYPE: { | 
|  | unsigned int frag_offset, frag_size, frag; | 
|  | u64 frag_blk; | 
|  | struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg; | 
|  |  | 
|  | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | 
|  | sizeof(*sqsh_ino)); | 
|  | if (err < 0) | 
|  | goto failed_read; | 
|  |  | 
|  | frag = le32_to_cpu(sqsh_ino->fragment); | 
|  | if (frag != SQUASHFS_INVALID_FRAG) { | 
|  | frag_offset = le32_to_cpu(sqsh_ino->offset); | 
|  | frag_size = squashfs_frag_lookup(sb, frag, &frag_blk); | 
|  | if (frag_size < 0) { | 
|  | err = frag_size; | 
|  | goto failed_read; | 
|  | } | 
|  | } else { | 
|  | frag_blk = SQUASHFS_INVALID_BLK; | 
|  | frag_size = 0; | 
|  | frag_offset = 0; | 
|  | } | 
|  |  | 
|  | inode->i_nlink = 1; | 
|  | inode->i_size = le32_to_cpu(sqsh_ino->file_size); | 
|  | inode->i_fop = &generic_ro_fops; | 
|  | inode->i_mode |= S_IFREG; | 
|  | inode->i_blocks = ((inode->i_size - 1) >> 9) + 1; | 
|  | squashfs_i(inode)->fragment_block = frag_blk; | 
|  | squashfs_i(inode)->fragment_size = frag_size; | 
|  | squashfs_i(inode)->fragment_offset = frag_offset; | 
|  | squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); | 
|  | squashfs_i(inode)->block_list_start = block; | 
|  | squashfs_i(inode)->offset = offset; | 
|  | inode->i_data.a_ops = &squashfs_aops; | 
|  |  | 
|  | TRACE("File inode %x:%x, start_block %llx, block_list_start " | 
|  | "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino), | 
|  | offset, squashfs_i(inode)->start, block, offset); | 
|  | break; | 
|  | } | 
|  | case SQUASHFS_LREG_TYPE: { | 
|  | unsigned int frag_offset, frag_size, frag; | 
|  | u64 frag_blk; | 
|  | struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg; | 
|  |  | 
|  | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | 
|  | sizeof(*sqsh_ino)); | 
|  | if (err < 0) | 
|  | goto failed_read; | 
|  |  | 
|  | frag = le32_to_cpu(sqsh_ino->fragment); | 
|  | if (frag != SQUASHFS_INVALID_FRAG) { | 
|  | frag_offset = le32_to_cpu(sqsh_ino->offset); | 
|  | frag_size = squashfs_frag_lookup(sb, frag, &frag_blk); | 
|  | if (frag_size < 0) { | 
|  | err = frag_size; | 
|  | goto failed_read; | 
|  | } | 
|  | } else { | 
|  | frag_blk = SQUASHFS_INVALID_BLK; | 
|  | frag_size = 0; | 
|  | frag_offset = 0; | 
|  | } | 
|  |  | 
|  | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | 
|  | inode->i_size = le64_to_cpu(sqsh_ino->file_size); | 
|  | inode->i_fop = &generic_ro_fops; | 
|  | inode->i_mode |= S_IFREG; | 
|  | inode->i_blocks = ((inode->i_size - | 
|  | le64_to_cpu(sqsh_ino->sparse) - 1) >> 9) + 1; | 
|  |  | 
|  | squashfs_i(inode)->fragment_block = frag_blk; | 
|  | squashfs_i(inode)->fragment_size = frag_size; | 
|  | squashfs_i(inode)->fragment_offset = frag_offset; | 
|  | squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block); | 
|  | squashfs_i(inode)->block_list_start = block; | 
|  | squashfs_i(inode)->offset = offset; | 
|  | inode->i_data.a_ops = &squashfs_aops; | 
|  |  | 
|  | TRACE("File inode %x:%x, start_block %llx, block_list_start " | 
|  | "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino), | 
|  | offset, squashfs_i(inode)->start, block, offset); | 
|  | break; | 
|  | } | 
|  | case SQUASHFS_DIR_TYPE: { | 
|  | struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir; | 
|  |  | 
|  | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | 
|  | sizeof(*sqsh_ino)); | 
|  | if (err < 0) | 
|  | goto failed_read; | 
|  |  | 
|  | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | 
|  | inode->i_size = le16_to_cpu(sqsh_ino->file_size); | 
|  | inode->i_op = &squashfs_dir_inode_ops; | 
|  | inode->i_fop = &squashfs_dir_ops; | 
|  | inode->i_mode |= S_IFDIR; | 
|  | squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); | 
|  | squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset); | 
|  | squashfs_i(inode)->dir_idx_cnt = 0; | 
|  | squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode); | 
|  |  | 
|  | TRACE("Directory inode %x:%x, start_block %llx, offset %x\n", | 
|  | SQUASHFS_INODE_BLK(ino), offset, | 
|  | squashfs_i(inode)->start, | 
|  | le16_to_cpu(sqsh_ino->offset)); | 
|  | break; | 
|  | } | 
|  | case SQUASHFS_LDIR_TYPE: { | 
|  | struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir; | 
|  |  | 
|  | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | 
|  | sizeof(*sqsh_ino)); | 
|  | if (err < 0) | 
|  | goto failed_read; | 
|  |  | 
|  | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | 
|  | inode->i_size = le32_to_cpu(sqsh_ino->file_size); | 
|  | inode->i_op = &squashfs_dir_inode_ops; | 
|  | inode->i_fop = &squashfs_dir_ops; | 
|  | inode->i_mode |= S_IFDIR; | 
|  | squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block); | 
|  | squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset); | 
|  | squashfs_i(inode)->dir_idx_start = block; | 
|  | squashfs_i(inode)->dir_idx_offset = offset; | 
|  | squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count); | 
|  | squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode); | 
|  |  | 
|  | TRACE("Long directory inode %x:%x, start_block %llx, offset " | 
|  | "%x\n", SQUASHFS_INODE_BLK(ino), offset, | 
|  | squashfs_i(inode)->start, | 
|  | le16_to_cpu(sqsh_ino->offset)); | 
|  | break; | 
|  | } | 
|  | case SQUASHFS_SYMLINK_TYPE: | 
|  | case SQUASHFS_LSYMLINK_TYPE: { | 
|  | struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink; | 
|  |  | 
|  | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | 
|  | sizeof(*sqsh_ino)); | 
|  | if (err < 0) | 
|  | goto failed_read; | 
|  |  | 
|  | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | 
|  | inode->i_size = le32_to_cpu(sqsh_ino->symlink_size); | 
|  | inode->i_op = &page_symlink_inode_operations; | 
|  | inode->i_data.a_ops = &squashfs_symlink_aops; | 
|  | inode->i_mode |= S_IFLNK; | 
|  | squashfs_i(inode)->start = block; | 
|  | squashfs_i(inode)->offset = offset; | 
|  |  | 
|  | TRACE("Symbolic link inode %x:%x, start_block %llx, offset " | 
|  | "%x\n", SQUASHFS_INODE_BLK(ino), offset, | 
|  | block, offset); | 
|  | break; | 
|  | } | 
|  | case SQUASHFS_BLKDEV_TYPE: | 
|  | case SQUASHFS_CHRDEV_TYPE: | 
|  | case SQUASHFS_LBLKDEV_TYPE: | 
|  | case SQUASHFS_LCHRDEV_TYPE: { | 
|  | struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev; | 
|  | unsigned int rdev; | 
|  |  | 
|  | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | 
|  | sizeof(*sqsh_ino)); | 
|  | if (err < 0) | 
|  | goto failed_read; | 
|  |  | 
|  | if (type == SQUASHFS_CHRDEV_TYPE) | 
|  | inode->i_mode |= S_IFCHR; | 
|  | else | 
|  | inode->i_mode |= S_IFBLK; | 
|  | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | 
|  | rdev = le32_to_cpu(sqsh_ino->rdev); | 
|  | init_special_inode(inode, inode->i_mode, new_decode_dev(rdev)); | 
|  |  | 
|  | TRACE("Device inode %x:%x, rdev %x\n", | 
|  | SQUASHFS_INODE_BLK(ino), offset, rdev); | 
|  | break; | 
|  | } | 
|  | case SQUASHFS_FIFO_TYPE: | 
|  | case SQUASHFS_SOCKET_TYPE: | 
|  | case SQUASHFS_LFIFO_TYPE: | 
|  | case SQUASHFS_LSOCKET_TYPE: { | 
|  | struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc; | 
|  |  | 
|  | err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset, | 
|  | sizeof(*sqsh_ino)); | 
|  | if (err < 0) | 
|  | goto failed_read; | 
|  |  | 
|  | if (type == SQUASHFS_FIFO_TYPE) | 
|  | inode->i_mode |= S_IFIFO; | 
|  | else | 
|  | inode->i_mode |= S_IFSOCK; | 
|  | inode->i_nlink = le32_to_cpu(sqsh_ino->nlink); | 
|  | init_special_inode(inode, inode->i_mode, 0); | 
|  | break; | 
|  | } | 
|  | default: | 
|  | ERROR("Unknown inode type %d in squashfs_iget!\n", type); | 
|  | return -EINVAL; | 
|  | } | 
|  |  | 
|  | return 0; | 
|  |  | 
|  | failed_read: | 
|  | ERROR("Unable to read inode 0x%llx\n", ino); | 
|  | return err; | 
|  | } |