linux-kernel - Re: [PATCH V4 5/6] erofs: Support sharing cookies in the same domain

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Date:   Fri, 16 Sep 2022 11:45:12 +0800
From:   JeffleXu <jefflexu@...ux.alibaba.com>
To:     Jia Zhu <zhujia.zj@...edance.com>, linux-erofs@...ts.ozlabs.org
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        yinxin.x@...edance.com
Subject: Re: [PATCH V4 5/6] erofs: Support sharing cookies in the same domain



On 9/15/22 8:42 PM, Jia Zhu wrote:

> +static
> +struct erofs_fscache *erofs_fscache_domain_init_cookie(struct super_block *sb,
> +							char *name, bool need_inode)
> +{
> +	int err;
> +	struct inode *inode;
> +	struct erofs_fscache *ctx;
> +	struct erofs_domain *domain = EROFS_SB(sb)->domain;
> +
> +	ctx = erofs_fscache_acquire_cookie(sb, name, need_inode);
> +	if (IS_ERR(ctx))
> +		return ctx;
> +
> +	ctx->name = kstrdup(name, GFP_KERNEL);
> +	if (!ctx->name) {
> +		err = -ENOMEM;
> +		goto out;
> +	}
> +
> +	inode = new_inode(erofs_pseudo_mnt->mnt_sb);
> +	if (!inode) {
> +		kfree(ctx->name);
> +		err = -ENOMEM;
> +		goto out;
> +	}
> +
> +	ctx->domain = domain;
> +	ctx->anon_inode = inode;
> +	inode->i_private = ctx;
> +	refcount_inc(&domain->ref);
> +	return ctx;
> +out:
> +	fscache_unuse_cookie(ctx->cookie, NULL, NULL);
> +	fscache_relinquish_cookie(ctx->cookie, false);
> +	if (need_inode)
> +		iput(ctx->inode);
> +	kfree(ctx);
> +	return ERR_PTR(err);

Could you please abstract the cleanup logic into one helper? like:

erofs_fscache_relinquish_cookie()
{
	fscache_unuse_cookie(ctx->cookie, NULL, NULL);
	fscache_relinquish_cookie(ctx->cookie, false);
	iput(ctx->inode);
	kfree(ctx->name);
	kfree(ctx);
}

which could also be called in erofs_fscache_unregister_cookie().


>  void erofs_fscache_unregister_cookie(struct erofs_fscache *ctx)
>  {
> +	bool drop;
> +	struct erofs_domain *domain;
> +
>  	if (!ctx)
>  		return;
> +	domain = ctx->domain;
> +	if (domain) {
> +		mutex_lock(&erofs_domain_cookies_lock);
> +		drop = atomic_read(&ctx->anon_inode->i_count) == 1;
> +		iput(ctx->anon_inode);
> +		mutex_unlock(&erofs_domain_cookies_lock);
> +		if (!drop)
> +			return;
> +	}
>  
>  	fscache_unuse_cookie(ctx->cookie, NULL, NULL);
>  	fscache_relinquish_cookie(ctx->cookie, false);
> +	erofs_fscache_domain_put(domain);
>  	iput(ctx->inode);
> +	kfree(ctx->name);
>  	kfree(ctx);
>  }


-- 
Thanks,
Jingbo