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Fri, 31 Jan 2020 16:41:27 -0800 (PST) To: Jens Axboe , io-uring References: From: Pavel Begunkov Autocrypt: addr=asml.silence@gmail.com; prefer-encrypt=mutual; keydata= mQINBFmKBOQBEAC76ZFxLAKpDw0bKQ8CEiYJRGn8MHTUhURL02/7n1t0HkKQx2K1fCXClbps bdwSHrhOWdW61pmfMbDYbTj6ZvGRvhoLWfGkzujB2wjNcbNTXIoOzJEGISHaPf6E2IQx1ik9 6uqVkK1OMb7qRvKH0i7HYP4WJzYbEWVyLiAxUj611mC9tgd73oqZ2pLYzGTqF2j6a/obaqha +hXuWTvpDQXqcOZJXIW43atprH03G1tQs7VwR21Q1eq6Yvy2ESLdc38EqCszBfQRMmKy+cfp W3U9Mb1w0L680pXrONcnlDBCN7/sghGeMHjGKfNANjPc+0hzz3rApPxpoE7HC1uRiwC4et83 CKnncH1l7zgeBT9Oa3qEiBlaa1ZCBqrA4dY+z5fWJYjMpwI1SNp37RtF8fKXbKQg+JuUjAa9 Y6oXeyEvDHMyJYMcinl6xCqCBAXPHnHmawkMMgjr3BBRzODmMr+CPVvnYe7BFYfoajzqzq+h EyXSl3aBf0IDPTqSUrhbmjj5OEOYgRW5p+mdYtY1cXeK8copmd+fd/eTkghok5li58AojCba jRjp7zVOLOjDlpxxiKhuFmpV4yWNh5JJaTbwCRSd04sCcDNlJj+TehTr+o1QiORzc2t+N5iJ NbILft19Izdn8U39T5oWiynqa1qCLgbuFtnYx1HlUq/HvAm+kwARAQABtDFQYXZlbCBCZWd1 bmtvdiAoc2lsZW5jZSkgPGFzbWwuc2lsZW5jZUBnbWFpbC5jb20+iQJOBBMBCAA4FiEE+6Ju PTjTbx479o3OWt5b1Glr+6UFAlmKBOQCGwMFCwkIBwIGFQgJCgsCBBYCAwECHgECF4AACgkQ Wt5b1Glr+6WxZA//QueaKHzgdnOikJ7NA/Vq8FmhRlwgtP0+E+w93kL+ZGLzS/cUCIjn2f4Q Mcutj2Neg0CcYPX3b2nJiKr5Vn0rjJ/suiaOa1h1KzyNTOmxnsqE5fmxOf6C6x+NKE18I5Jy xzLQoktbdDVA7JfB1itt6iWSNoOTVcvFyvfe5ggy6FSCcP+m1RlR58XxVLH+qlAvxxOeEr/e aQfUzrs7gqdSd9zQGEZo0jtuBiB7k98t9y0oC9Jz0PJdvaj1NZUgtXG9pEtww3LdeXP/TkFl HBSxVflzeoFaj4UAuy8+uve7ya/ECNCc8kk0VYaEjoVrzJcYdKP583iRhOLlZA6HEmn/+Gh9 4orG67HNiJlbFiW3whxGizWsrtFNLsSP1YrEReYk9j1SoUHHzsu+ZtNfKuHIhK0sU07G1OPN 2rDLlzUWR9Jc22INAkhVHOogOcc5ajMGhgWcBJMLCoi219HlX69LIDu3Y34uIg9QPZIC2jwr 24W0kxmK6avJr7+n4o8m6sOJvhlumSp5TSNhRiKvAHB1I2JB8Q1yZCIPzx+w1ALxuoWiCdwV M/azguU42R17IuBzK0S3hPjXpEi2sK/k4pEPnHVUv9Cu09HCNnd6BRfFGjo8M9kZvw360gC1 reeMdqGjwQ68o9x0R7NBRrtUOh48TDLXCANAg97wjPoy37dQE7e5Ag0EWYoE5AEQAMWS+aBV IJtCjwtfCOV98NamFpDEjBMrCAfLm7wZlmXy5I6o7nzzCxEw06P2rhzp1hIqkaab1kHySU7g dkpjmQ7Jjlrf6KdMP87mC/Hx4+zgVCkTQCKkIxNE76Ff3O9uTvkWCspSh9J0qPYyCaVta2D1 Sq5HZ8WFcap71iVO1f2/FEHKJNz/YTSOS/W7dxJdXl2eoj3gYX2UZNfoaVv8OXKaWslZlgqN jSg9wsTv1K73AnQKt4fFhscN9YFxhtgD/SQuOldE5Ws4UlJoaFX/yCoJL3ky2kC0WFngzwRF Yo6u/KON/o28yyP+alYRMBrN0Dm60FuVSIFafSqXoJTIjSZ6olbEoT0u17Rag8BxnxryMrgR dkccq272MaSS0eOC9K2rtvxzddohRFPcy/8bkX+t2iukTDz75KSTKO+chce62Xxdg62dpkZX xK+HeDCZ7gRNZvAbDETr6XI63hPKi891GeZqvqQVYR8e+V2725w+H1iv3THiB1tx4L2bXZDI DtMKQ5D2RvCHNdPNcZeldEoJwKoA60yg6tuUquvsLvfCwtrmVI2rL2djYxRfGNmFMrUDN1Xq F3xozA91q3iZd9OYi9G+M/OA01husBdcIzj1hu0aL+MGg4Gqk6XwjoSxVd4YT41kTU7Kk+/I 5/Nf+i88ULt6HanBYcY/+Daeo/XFABEBAAGJAjYEGAEIACAWIQT7om49ONNvHjv2jc5a3lvU aWv7pQUCWYoE5AIbDAAKCRBa3lvUaWv7pfmcEACKTRQ28b1y5ztKuLdLr79+T+LwZKHjX++P 4wKjEOECCcB6KCv3hP+J2GCXDOPZvdg/ZYZafqP68Yy8AZqkfa4qPYHmIdpODtRzZSL48kM8 LRzV8Rl7J3ItvzdBRxf4T/Zseu5U6ELiQdCUkPGsJcPIJkgPjO2ROG/ZtYa9DvnShNWPlp+R uPwPccEQPWO/NP4fJl2zwC6byjljZhW5kxYswGMLBwb5cDUZAisIukyAa8Xshdan6C2RZcNs rB3L7vsg/R8UCehxOH0C+NypG2GqjVejNZsc7bgV49EOVltS+GmGyY+moIzxsuLmT93rqyII 5rSbbcTLe6KBYcs24XEoo49Zm9oDA3jYvNpeYD8rDcnNbuZh9kTgBwFN41JHOPv0W2FEEWqe JsCwQdcOQ56rtezdCJUYmRAt3BsfjN3Jn3N6rpodi4Dkdli8HylM5iq4ooeb5VkQ7UZxbCWt UVMKkOCdFhutRmYp0mbv2e87IK4erwNHQRkHUkzbsuym8RVpAZbLzLPIYK/J3RTErL6Z99N2 m3J6pjwSJY/zNwuFPs9zGEnRO4g0BUbwGdbuvDzaq6/3OJLKohr5eLXNU3JkT+3HezydWm3W OPhauth7W0db74Qd49HXK0xe/aPrK+Cp+kU1HRactyNtF8jZQbhMCC8vMGukZtWaAwpjWiiH bA== Subject: Re: [PATCH] io_uring: fix sporadic double CQE entry for close Message-ID: Date: Sat, 1 Feb 2020 03:40:48 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="RqkCsk6WtVLjEPdCVgs8OJ53FvVlyo1D1" Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --RqkCsk6WtVLjEPdCVgs8OJ53FvVlyo1D1 Content-Type: multipart/mixed; boundary="2CQYOmd0DwcQt8UcdkFVc9cZqZFgjBqzk"; protected-headers="v1" From: Pavel Begunkov To: Jens Axboe , io-uring Message-ID: Subject: Re: [PATCH] io_uring: fix sporadic double CQE entry for close References: In-Reply-To: --2CQYOmd0DwcQt8UcdkFVc9cZqZFgjBqzk Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 01/02/2020 03:21, Jens Axboe wrote: > We punt close to async for the final fput(), but we log the completion > even before that even in that case. We rely on the request not having > a files table assigned to detect what the final async close should do. > However, if we punt the async queue to __io_queue_sqe(), we'll get > ->files assigned and this makes io_close_finish() think it should both > close the filp again (which does no harm) AND log a new CQE event for > this request. This causes duplicate CQEs. >=20 > Queue the request up for async manually so we don't grab files > needlessly and trigger this condition. >=20 Evidently from your 2 last patches, it's becoming hard to track everythin= g in the current state. As mentioned, I'm going to rework and fix submission a= nd prep paths with a bit of formalisation. > Signed-off-by: Jens Axboe >=20 > --- >=20 > diff --git a/fs/io_uring.c b/fs/io_uring.c > index cb3c0a803b46..fb5c5b3e23f4 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -2841,16 +2841,13 @@ static void io_close_finish(struct io_wq_work *= *workptr) > int ret; > =20 > ret =3D filp_close(req->close.put_file, req->work.files); > - if (ret < 0) { > + if (ret < 0) > req_set_fail_links(req); > - } > io_cqring_add_event(req, ret); > } > =20 > fput(req->close.put_file); > =20 > - /* we bypassed the re-issue, drop the submission reference */ > - io_put_req(req); > io_put_req_find_next(req, &nxt); > if (nxt) > io_wq_assign_next(workptr, nxt); > @@ -2892,7 +2889,13 @@ static int io_close(struct io_kiocb *req, struct= io_kiocb **nxt, > =20 > eagain: > req->work.func =3D io_close_finish; > - return -EAGAIN; > + /* > + * Do manual async queue here to avoid grabbing files - we don't > + * need the files, and it'll cause io_close_finish() to close > + * the file again and cause a double CQE entry for this request > + */ > + io_queue_async_work(req); > + return 0; > } > =20 > static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe= *sqe) >=20 --=20 Pavel Begunkov --2CQYOmd0DwcQt8UcdkFVc9cZqZFgjBqzk-- --RqkCsk6WtVLjEPdCVgs8OJ53FvVlyo1D1 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE+6JuPTjTbx479o3OWt5b1Glr+6UFAl40yRAACgkQWt5b1Glr +6Xvnw/8CUG9cfIKrszNFwSFyXrx0jNgoot2QqNFzp+0anXvZdPOALrSnbswdUOb UFy1rg9trgnYL2Q24M/jT+ZMoKeLt9Ee9pO0QDo4tLDAjcDczGzcXvZU64+dHvI3 KAkiYOF3i2MV+KTkw5RDtk/0w+a1gq1vYiXETSnFJ3kT0nDT0ahN0rR8uBDNkgdo OXc5z8J3108sSipNmuZPdaBZkwDaKPDzraoZU43Y9f6yoGEZbAIBNAM9ooEOzaJ9 5c1xIx4rKo0xwUVH3YqxjNctTmr9QiIgYBkGQLB/rLVKatLP2GEtNF4u6yrDp4gr 4x4ljwpTpZR2HXCoyAa5YgeG8nnUIeIej8QfUzvQCeHhqcxbKW0zbx5OslA5gosc Pbk1h3chusyOELQ79KugOcUWkSUdpPXEA16IfzoOvq/M3oP72EHboSN6dZTxycPl q4vW9fACTQFxLg+dzSfnXMf5e3OooUD1bGeIFALZEiZ5l/e6JvOdFL4XvpDC5M4U UTpVIHD4PxkUE6xprTSeFiCyTQwIVMdm0adsEGva3XoD1SMj1uputgcJZcfnwKaV 16Ez0M9UiBBPhu/NrVwKZoEDQ4g+ihc8GKOVgaPGDMJL0HVM1BigJV8hKS1m5jHu WBR1H8omSE680W1pA2FBYrQG1w93SMCarMNslgGkJ06oVANmdkg= =8SYK -----END PGP SIGNATURE----- --RqkCsk6WtVLjEPdCVgs8OJ53FvVlyo1D1--