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Message-ID: <ef4cc431-4cc4-eb39-735d-0b3b3759abed@redhat.com>
Date:   Mon, 22 May 2023 09:53:28 +0800
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Subject: Re: [PATCH v20 13/32] ceph: Provide a splice-read stub
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To:     David Howells <dhowells@redhat.com>
Cc:     Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
        Jeff Layton <jlayton@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        Hillf Danton <hdanton@sina.com>,
        Christian Brauner <brauner@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Christoph Hellwig <hch@lst.de>,
        Ilya Dryomov <idryomov@gmail.com>, ceph-devel@vger.kernel.org
References: <c1fd63b9-42ea-fa83-ecb1-9af715e37ffa@redhat.com>
 <20230519074047.1739879-1-dhowells@redhat.com>
 <20230519074047.1739879-14-dhowells@redhat.com>
 <1743656.1684488288@warthog.procyon.org.uk>
From:   Xiubo Li <xiubli@redhat.com>
In-Reply-To: <1743656.1684488288@warthog.procyon.org.uk>
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On 5/19/23 17:24, David Howells wrote:
> Xiubo Li <xiubli@redhat.com> wrote:
>
>>> +	ret = ceph_get_caps(in, CEPH_CAP_FILE_RD, want, -1, &got);
>>> +	if (ret < 0) {
>>> +		ceph_end_io_read(inode);
>>> +		return ret;
>>> +	}
>>> +
>>> +	if ((got & (CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO)) == 0) {
>>> +		dout("splice_read/sync %p %llx.%llx %llu~%zu got cap refs on %s\n",
>>> +		     inode, ceph_vinop(inode), *ppos, len,
>>> +		     ceph_cap_string(got));
>>> +
>>> +		ceph_end_io_read(inode);
>>> +		return direct_splice_read(in, ppos, pipe, len, flags);
>> Shouldn't we release cap ref before returning here ?
> Ummm...  Even if we got no caps?

No, at least we have got the 'need' caps: CEPH_CAP_FILE_RD once here.

I saw you have updated this and will check it.

Thanks

- Xiubo

>
> David
>