Squashfs: inode operations
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
This commit is contained in:
Phillip Lougher
Родитель
fe0bdec68b
Коммит
6545b246a2
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/*
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* Squashfs - a compressed read only filesystem for Linux
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*
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* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
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* Phillip Lougher <phillip@lougher.demon.co.uk>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2,
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* or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* inode.c
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*/
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/*
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* This file implements code to create and read inodes from disk.
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*
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* Inodes in Squashfs are identified by a 48-bit inode which encodes the
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* location of the compressed metadata block containing the inode, and the byte
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* offset into that block where the inode is placed (<block, offset>).
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*
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* To maximise compression there are different inodes for each file type
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* (regular file, directory, device, etc.), the inode contents and length
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* varying with the type.
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*
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* To further maximise compression, two types of regular file inode and
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* directory inode are defined: inodes optimised for frequently occurring
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* regular files and directories, and extended types where extra
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* information has to be stored.
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*/
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#include <linux/fs.h>
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#include <linux/vfs.h>
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#include <linux/zlib.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "squashfs_fs_i.h"
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#include "squashfs.h"
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/*
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* Initialise VFS inode with the base inode information common to all
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* Squashfs inode types. Sqsh_ino contains the unswapped base inode
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* off disk.
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*/
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static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
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struct squashfs_base_inode *sqsh_ino)
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{
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int err;
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err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &inode->i_uid);
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if (err)
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return err;
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err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &inode->i_gid);
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if (err)
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return err;
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inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
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inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime);
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inode->i_atime.tv_sec = inode->i_mtime.tv_sec;
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inode->i_ctime.tv_sec = inode->i_mtime.tv_sec;
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inode->i_mode = le16_to_cpu(sqsh_ino->mode);
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inode->i_size = 0;
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return err;
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}
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struct inode *squashfs_iget(struct super_block *sb, long long ino,
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unsigned int ino_number)
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{
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struct inode *inode = iget_locked(sb, ino_number);
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int err;
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TRACE("Entered squashfs_iget\n");
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if (!inode)
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return ERR_PTR(-ENOMEM);
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if (!(inode->i_state & I_NEW))
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return inode;
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err = squashfs_read_inode(inode, ino);
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if (err) {
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iget_failed(inode);
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return ERR_PTR(err);
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}
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unlock_new_inode(inode);
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return inode;
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}
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/*
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* Initialise VFS inode by reading inode from inode table (compressed
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* metadata). The format and amount of data read depends on type.
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*/
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int squashfs_read_inode(struct inode *inode, long long ino)
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{
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struct super_block *sb = inode->i_sb;
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struct squashfs_sb_info *msblk = sb->s_fs_info;
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u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
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int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
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union squashfs_inode squashfs_ino;
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struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
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TRACE("Entered squashfs_read_inode\n");
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/*
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* Read inode base common to all inode types.
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*/
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err = squashfs_read_metadata(sb, sqshb_ino, &block,
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&offset, sizeof(*sqshb_ino));
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if (err < 0)
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goto failed_read;
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err = squashfs_new_inode(sb, inode, sqshb_ino);
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if (err)
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goto failed_read;
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block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
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offset = SQUASHFS_INODE_OFFSET(ino);
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type = le16_to_cpu(sqshb_ino->inode_type);
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switch (type) {
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case SQUASHFS_REG_TYPE: {
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unsigned int frag_offset, frag_size, frag;
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u64 frag_blk;
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struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
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err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
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sizeof(*sqsh_ino));
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if (err < 0)
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goto failed_read;
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frag = le32_to_cpu(sqsh_ino->fragment);
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if (frag != SQUASHFS_INVALID_FRAG) {
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frag_offset = le32_to_cpu(sqsh_ino->offset);
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frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
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if (frag_size < 0) {
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err = frag_size;
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goto failed_read;
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}
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} else {
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frag_blk = SQUASHFS_INVALID_BLK;
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frag_size = 0;
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frag_offset = 0;
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}
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inode->i_nlink = 1;
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inode->i_size = le32_to_cpu(sqsh_ino->file_size);
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inode->i_fop = &generic_ro_fops;
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inode->i_mode |= S_IFREG;
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inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
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squashfs_i(inode)->fragment_block = frag_blk;
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squashfs_i(inode)->fragment_size = frag_size;
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squashfs_i(inode)->fragment_offset = frag_offset;
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squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
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squashfs_i(inode)->block_list_start = block;
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squashfs_i(inode)->offset = offset;
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inode->i_data.a_ops = &squashfs_aops;
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TRACE("File inode %x:%x, start_block %llx, block_list_start "
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"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
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offset, squashfs_i(inode)->start, block, offset);
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break;
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}
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case SQUASHFS_LREG_TYPE: {
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unsigned int frag_offset, frag_size, frag;
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u64 frag_blk;
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struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
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err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
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sizeof(*sqsh_ino));
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if (err < 0)
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goto failed_read;
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frag = le32_to_cpu(sqsh_ino->fragment);
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if (frag != SQUASHFS_INVALID_FRAG) {
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frag_offset = le32_to_cpu(sqsh_ino->offset);
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frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
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if (frag_size < 0) {
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err = frag_size;
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goto failed_read;
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}
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} else {
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frag_blk = SQUASHFS_INVALID_BLK;
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frag_size = 0;
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frag_offset = 0;
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}
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inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
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inode->i_size = le64_to_cpu(sqsh_ino->file_size);
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inode->i_fop = &generic_ro_fops;
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inode->i_mode |= S_IFREG;
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inode->i_blocks = ((inode->i_size -
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le64_to_cpu(sqsh_ino->sparse) - 1) >> 9) + 1;
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squashfs_i(inode)->fragment_block = frag_blk;
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squashfs_i(inode)->fragment_size = frag_size;
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squashfs_i(inode)->fragment_offset = frag_offset;
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squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
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squashfs_i(inode)->block_list_start = block;
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squashfs_i(inode)->offset = offset;
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inode->i_data.a_ops = &squashfs_aops;
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TRACE("File inode %x:%x, start_block %llx, block_list_start "
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"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
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offset, squashfs_i(inode)->start, block, offset);
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break;
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}
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case SQUASHFS_DIR_TYPE: {
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struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
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err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
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sizeof(*sqsh_ino));
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if (err < 0)
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goto failed_read;
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inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
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inode->i_size = le16_to_cpu(sqsh_ino->file_size);
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inode->i_op = &squashfs_dir_inode_ops;
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inode->i_fop = &squashfs_dir_ops;
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inode->i_mode |= S_IFDIR;
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squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
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squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
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squashfs_i(inode)->dir_idx_cnt = 0;
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squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
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TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
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SQUASHFS_INODE_BLK(ino), offset,
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squashfs_i(inode)->start,
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le16_to_cpu(sqsh_ino->offset));
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break;
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}
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case SQUASHFS_LDIR_TYPE: {
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struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
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err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
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sizeof(*sqsh_ino));
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if (err < 0)
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goto failed_read;
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inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
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inode->i_size = le32_to_cpu(sqsh_ino->file_size);
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inode->i_op = &squashfs_dir_inode_ops;
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inode->i_fop = &squashfs_dir_ops;
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inode->i_mode |= S_IFDIR;
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squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
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squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
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squashfs_i(inode)->dir_idx_start = block;
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squashfs_i(inode)->dir_idx_offset = offset;
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squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
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squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
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TRACE("Long directory inode %x:%x, start_block %llx, offset "
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"%x\n", SQUASHFS_INODE_BLK(ino), offset,
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squashfs_i(inode)->start,
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le16_to_cpu(sqsh_ino->offset));
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break;
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}
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case SQUASHFS_SYMLINK_TYPE:
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case SQUASHFS_LSYMLINK_TYPE: {
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struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
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err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
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sizeof(*sqsh_ino));
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if (err < 0)
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goto failed_read;
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inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
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inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
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inode->i_op = &page_symlink_inode_operations;
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inode->i_data.a_ops = &squashfs_symlink_aops;
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inode->i_mode |= S_IFLNK;
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squashfs_i(inode)->start = block;
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squashfs_i(inode)->offset = offset;
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TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
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"%x\n", SQUASHFS_INODE_BLK(ino), offset,
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block, offset);
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break;
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}
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case SQUASHFS_BLKDEV_TYPE:
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case SQUASHFS_CHRDEV_TYPE:
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case SQUASHFS_LBLKDEV_TYPE:
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case SQUASHFS_LCHRDEV_TYPE: {
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struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
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unsigned int rdev;
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err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
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sizeof(*sqsh_ino));
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if (err < 0)
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goto failed_read;
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if (type == SQUASHFS_CHRDEV_TYPE)
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inode->i_mode |= S_IFCHR;
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else
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inode->i_mode |= S_IFBLK;
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inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
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rdev = le32_to_cpu(sqsh_ino->rdev);
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init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
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TRACE("Device inode %x:%x, rdev %x\n",
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SQUASHFS_INODE_BLK(ino), offset, rdev);
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break;
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}
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case SQUASHFS_FIFO_TYPE:
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case SQUASHFS_SOCKET_TYPE:
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case SQUASHFS_LFIFO_TYPE:
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case SQUASHFS_LSOCKET_TYPE: {
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struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
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err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
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sizeof(*sqsh_ino));
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if (err < 0)
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goto failed_read;
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if (type == SQUASHFS_FIFO_TYPE)
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inode->i_mode |= S_IFIFO;
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else
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inode->i_mode |= S_IFSOCK;
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inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
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init_special_inode(inode, inode->i_mode, 0);
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break;
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}
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default:
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ERROR("Unknown inode type %d in squashfs_iget!\n", type);
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return -EINVAL;
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}
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return 0;
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failed_read:
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ERROR("Unable to read inode 0x%llx\n", ino);
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return err;
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}
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