| /* |
| * 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 "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; |
| } |