/* * 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; int frag_size; 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; int frag_size; 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; }