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    Subject[PATCH V2 01/16] Squashfs: inode operations
    From
    Date

    Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
    ---
    fs/squashfs/inode.c | 346 +++++++++++++++++++++++++++++++++++++++++++++++++++
    1 files changed, 346 insertions(+), 0 deletions(-)

    diff --git a/fs/squashfs/inode.c b/fs/squashfs/inode.c
    new file mode 100644
    index 0000000..840c82b
    --- /dev/null
    +++ b/fs/squashfs/inode.c
    @@ -0,0 +1,346 @@
    +/*
    + * 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;
    + long long 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;
    + long long 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 = get_fragment_location(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;
    + long long 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 = get_fragment_location(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;
    +}
    --
    1.5.2.5


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