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From:   David Howells <dhowells@redhat.com>
In-Reply-To: <20230329140155.53272-6-zhujia.zj@bytedance.com>
References: <20230329140155.53272-6-zhujia.zj@bytedance.com> <20230329140155.53272-1-zhujia.zj@bytedance.com>
To:     Jia Zhu <zhujia.zj@bytedance.com>
Cc:     dhowells@redhat.com, linux-cachefs@redhat.com,
        linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        jefflexu@linux.alibaba.com, hsiangkao@linux.alibaba.com,
        yinxin.x@bytedance.com
Subject: Re: [PATCH V5 5/5] cachefiles: add restore command to recover inflight ondemand read requests
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Content-ID: <1250438.1681480404.1@warthog.procyon.org.uk>
Date:   Fri, 14 Apr 2023 14:53:24 +0100
Message-ID: <1250439.1681480404@warthog.procyon.org.uk>
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Jia Zhu <zhujia.zj@bytedance.com> wrote:

> +int cachefiles_ondemand_restore(struct cachefiles_cache *cache, char *args)
> +{
> +	struct cachefiles_req *req;
> +
> +	XA_STATE(xas, &cache->reqs, 0);
> +
> +	if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags))
> +		return -EOPNOTSUPP;
> +
> +	/*
> +	 * Reset the requests to CACHEFILES_REQ_NEW state, so that the
> +	 * requests have been processed halfway before the crash of the
> +	 * user daemon could be reprocessed after the recovery.
> +	 */
> +	xas_lock(&xas);
> +	xas_for_each(&xas, req, ULONG_MAX)
> +		xas_set_mark(&xas, CACHEFILES_REQ_NEW);
> +	xas_unlock(&xas);
> +
> +	wake_up_all(&cache->daemon_pollwq);
> +	return 0;
> +}

Should there be a check to see if this is needed?

David