// root the info for root directory from disk and store it in inode
// Return Value: -1 : error
int fat_read_root(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct fat_sb_info *sbi = MSDOS_SB(sb);
int error = 0;
printk (KERN_INFO "myfat: fat_read_root\n");
MSDOS_I(inode)->i_pos = 0;
inode->i_uid = sbi->options.fs_uid;
inode->i_gid = sbi->options.fs_gid;
inode->i_version++;
inode->i_generation = 0;
inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
inode->i_op = sbi->dir_ops;
inode->i_fop = &fat_dir_operations;
if (sbi->fat_bits == 32) {
MSDOS_I(inode)->i_start = sbi->root_cluster;
// the size of the file for Root Dir
error = fat_calc_dir_size(inode);
if (error < 0)
return error;
} else {
MSDOS_I(inode)->i_start = 0;
// the size of the file for Root Dir
inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
}
inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
& ~((loff_t)sbi->cluster_size - 1)) >> 9; // why 9?
// what if cluster size isn't 512? todo
MSDOS_I(inode)->i_logstart = 0;
MSDOS_I(inode)->mmu_private = inode->i_size; // rzq: I don't use this now
// no idea what it is
fat_save_attrs(inode, ATTR_DIR); // the is a directory
inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
inode->i_nlink = fat_subdirs(inode)+2; // count in . and ..
return 0;
}
static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
{
struct inode *inode = file_inode(file);
struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
int is_dir = S_ISDIR(inode->i_mode);
u32 attr, oldattr;
struct iattr ia;
int err;
err = get_user(attr, user_attr);
if (err)
goto out;
err = mnt_want_write_file(file);
if (err)
goto out;
inode_lock(inode);
/*
* ATTR_VOLUME and ATTR_DIR cannot be changed; this also
* prevents the user from turning us into a VFAT
* longname entry. Also, we obviously can't set
* any of the NTFS attributes in the high 24 bits.
*/
attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR);
/* Merge in ATTR_VOLUME and ATTR_DIR */
attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
(is_dir ? ATTR_DIR : 0);
oldattr = fat_make_attrs(inode);
/* Equivalent to a chmod() */
ia.ia_valid = ATTR_MODE | ATTR_CTIME;
ia.ia_ctime = current_time(inode);
if (is_dir)
ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
else {
ia.ia_mode = fat_make_mode(sbi, attr,
S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO));
}
/* The root directory has no attributes */
if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
err = -EINVAL;
goto out_unlock_inode;
}
if (sbi->options.sys_immutable &&
((attr | oldattr) & ATTR_SYS) &&
!capable(CAP_LINUX_IMMUTABLE)) {
err = -EPERM;
goto out_unlock_inode;
}
/*
* The security check is questionable... We single
* out the RO attribute for checking by the security
* module, just because it maps to a file mode.
*/
err = security_inode_setattr(file->f_path.dentry, &ia);
if (err)
goto out_unlock_inode;
/* This MUST be done before doing anything irreversible... */
err = fat_setattr(file->f_path.dentry, &ia);
if (err)
goto out_unlock_inode;
fsnotify_change(file->f_path.dentry, ia.ia_valid);
if (sbi->options.sys_immutable) {
if (attr & ATTR_SYS)
inode->i_flags |= S_IMMUTABLE;
else
inode->i_flags &= ~S_IMMUTABLE;
}
fat_save_attrs(inode, attr);
mark_inode_dirty(inode);
out_unlock_inode:
inode_unlock(inode);
mnt_drop_write_file(file);
out:
return err;
}
