Re: [PATCH v4 19/19] fs: handle inode->i_version more efficiently

[Matthew Wilcox]

On Fri, Dec 22, 2017 at 07:05:56AM -0500, Jeff Layton wrote:
> +	cur = inode_peek_iversion_raw(inode);
> +	for (;;) {
> +		/* If flag is clear then we needn't do anything */
> +		if (!force && !(cur & I_VERSION_QUERIED))
> +			return false;
> +		/* Since lowest bit is flag, add 2 to avoid it */
> +		new = (cur & ~I_VERSION_QUERIED) + I_VERSION_INCREMENT;

Isn't this an extraordinarily complicated way of spelling:

		new = cur + 1;

We know 'cur' has I_VERSION_QUERIED set, so clearing that bit and adding
two is going to be the same as adding 1 ... right?