linux-imx

/*

 * Optimized MPEG FS - inode and super operations.

 * Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>

 * Released under GPL v2.

 */

#include <linux/module.h>

#include <linux/sched.h>

#include <linux/slab.h>

#include <linux/fs.h>

#include <linux/vfs.h>

#include <linux/cred.h>

#include <linux/parser.h>

#include <linux/buffer_head.h>

#include <linux/vmalloc.h>

#include <linux/writeback.h>

#include <linux/seq_file.h>

#include <linux/crc-itu-t.h>

#include "omfs.h"

​

MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");

MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");

MODULE_LICENSE("GPL");

​

struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)

{

    struct omfs_sb_info *sbi = OMFS_SB(sb);

    if (block >= sbi->s_num_blocks)

        return NULL;

​

    return sb_bread(sb, clus_to_blk(sbi, block));

}

​

struct inode *omfs_new_inode(struct inode *dir, umode_t mode)

{

    struct inode *inode;

    u64 new_block;

    int err;

    int len;

    struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);

​

    inode = new_inode(dir->i_sb);

    if (!inode)

        return ERR_PTR(-ENOMEM);

​

    err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,

            &new_block, &len);

    if (err)

        goto fail;

​

    inode->i_ino = new_block;

    inode_init_owner(inode, NULL, mode);

    inode->i_mapping->a_ops = &omfs_aops;

​

    inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);

    switch (mode & S_IFMT) {

    case S_IFDIR:

        inode->i_op = &omfs_dir_inops;

        inode->i_fop = &omfs_dir_operations;

        inode->i_size = sbi->s_sys_blocksize;

        inc_nlink(inode);

        break;

    case S_IFREG:

        inode->i_op = &omfs_file_inops;

        inode->i_fop = &omfs_file_operations;

        inode->i_size = 0;

        break;

    }

​

    insert_inode_hash(inode);

    mark_inode_dirty(inode);

    return inode;

fail:

    make_bad_inode(inode);

    iput(inode);

    return ERR_PTR(err);

}

​

/*

 * Update the header checksums for a dirty inode based on its contents.

 * Caller is expected to hold the buffer head underlying oi and mark it

 * dirty.

 */

static void omfs_update_checksums(struct omfs_inode *oi)

{

    int xor, i, ofs = 0, count;

    u16 crc = 0;

    unsigned char *ptr = (unsigned char *) oi;

​

    count = be32_to_cpu(oi->i_head.h_body_size);

    ofs = sizeof(struct omfs_header);

​

    crc = crc_itu_t(crc, ptr + ofs, count);