static int ext4_block_truncate_page(handle_t *handle,
		struct address_space *mapping, loff_t from)
{
	unsigned offset = from & (PAGE_SIZE-1);
	unsigned length;
	unsigned blocksize;
	struct inode *inode = mapping->host;

	/* If we are processing an encrypted inode during orphan list handling */
	if (ext4_encrypted_inode(inode) && !fscrypt_has_encryption_key(inode))
		return 0;

	blocksize = inode->i_sb->s_blocksize;
	length = blocksize - (offset & (blocksize - 1));

	return ext4_block_zero_page_range(handle, mapping, from, length);
}
Unknown