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Wong" , Sasha Levin Subject: [PATCH AUTOSEL 4.14 74/87] iomap: complete partial direct I/O writes synchronously Thread-Topic: [PATCH AUTOSEL 4.14 74/87] iomap: complete partial direct I/O writes synchronously Thread-Index: AQHUTjL41lQb7aNja0O9+230DB7mBA== Date: Mon, 17 Sep 2018 03:03:12 +0000 Message-ID: <20180917030220.245686-74-alexander.levin@microsoft.com> References: <20180917030220.245686-1-alexander.levin@microsoft.com> In-Reply-To: <20180917030220.245686-1-alexander.levin@microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [52.168.54.252] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;CY4PR21MB0133;6:Bbfv0lr/h4F5vQkMjfMAVHV7Zgx4d7KySooE2JRw1bd2p1wBPn/DQHE6tqTUfPZ77Ra5vvZnvo9qerri8diHlFrzEmPyV4RT4+0UDr5OBFuDXvjfgZ7x5kc0F1MiCgH7oqBlrXhMDe0KhYP0gGsFJTt2+KIpKx+0Y7ydZyqlr5Xp79emz1rOHipD/IkEuCAYeTA4LfsdYQw0hNBYFC0NTXacj3MsSDiJrGxUnhSEBHGUh3arGp/svj556vHFjRkJWhdWl0V7nrAmrXBzB8o5m9FxrG8mkEdn0aPEuSmDVqrYnPg24itcxpsN7ykqYfWxhzeK+chIJWqPXtAq2zWe9OqZxNlWAzJDceXe8eAWrcT07dswrXLpZL5kfWzl1uYz1E0xPGsK/qbYChSiQjWZ1igESocIb6baDWCHzH8d/gS15Va8L0d9bWAbD48a3YD1Irpvy/0WMcaA5sxNsyEusQ==;5:28QCm7G/sa9asQXFr4bRfmR9KoXI64DUH0m1bGeIEwr1GXkm/g8wBFD0w6YdIc+pWsCDmeaZcphKvN1YRM1XWdalzEl+IiCBB7Il9iHlovg0QafUwXL9un1Gi5Jb3q/76K63+Ki6+fIUUM/Ts+MLcmxekOlJmTq+Kpij05Nok4M=;7:Ig22jmgXJ1N6hDhkfr6odj+RPxgIdfP9+HjenPOgusvIniHRAADSfTHhEaGz3JJq2BamWtKYK/KjhRbs49WkuqWOlzkekgvkDH3nOF/dR0Zi2xT96opwenKQF4wmPoEQuFlbevZxcM5tm2gQHIT1zrRPTWyOvfJX/CYNVzEp/6zjvnVUFuyFURwgSEryNnDw+1cCIVzIAzBX5LAN/Cb3nrvWCMCpFRzR0OR1Ot4SnzKICBmvbdu12QGEktjQcHyr x-ms-office365-filtering-correlation-id: b23e3a1c-6c4c-42ff-04f0-08d61c4a5b01 x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: BCL:0;PCL:0;RULEID:(7020095)(4652040)(8989137)(4534165)(4627221)(201703031133081)(201702281549075)(8990107)(5600074)(711020)(4618075)(2017052603328)(7193020);SRVR:CY4PR21MB0133; x-ms-traffictypediagnostic: CY4PR21MB0133: authentication-results: spf=none (sender IP is ) smtp.mailfrom=Alexander.Levin@microsoft.com; x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(278428928389397)(146099531331640)(28532068793085)(89211679590171); x-ms-exchange-senderadcheck: 1 x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(8211001083)(6040522)(2401047)(8121501046)(5005006)(10201501046)(3231355)(944501410)(52105095)(2018427008)(3002001)(93006095)(93001095)(6055026)(149027)(150027)(6041310)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123560045)(20161123562045)(20161123558120)(20161123564045)(201708071742011)(7699050)(76991041);SRVR:CY4PR21MB0133;BCL:0;PCL:0;RULEID:;SRVR:CY4PR21MB0133; x-forefront-prvs: 0798146F16 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(366004)(136003)(396003)(39860400002)(376002)(346002)(189003)(199004)(102836004)(53936002)(8676002)(486006)(476003)(3846002)(6116002)(76176011)(10290500003)(97736004)(217873002)(256004)(5660300001)(107886003)(6506007)(478600001)(110136005)(2501003)(10090500001)(305945005)(7736002)(446003)(11346002)(36756003)(2906002)(1076002)(22452003)(5250100002)(2616005)(26005)(316002)(106356001)(25786009)(68736007)(86362001)(575784001)(14454004)(72206003)(105586002)(99286004)(6486002)(6436002)(6512007)(86612001)(6666003)(81166006)(81156014)(186003)(2900100001)(54906003)(8936002)(4326008)(66066001);DIR:OUT;SFP:1102;SCL:1;SRVR:CY4PR21MB0133;H:CY4PR21MB0776.namprd21.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A:1; received-spf: None (protection.outlook.com: microsoft.com does not designate permitted sender hosts) x-microsoft-antispam-message-info: xOZmhxVgLHYwACZx2N1FbKNJxyQ1mBbdijQVZZ+s1ocDgoR7XlZUF45bIIzJKaNB8Ybeby9HvMbpV8DB4QuHa57DS+nqqrnYNL0WCG8l8MFNFwdpUp7fbIG9kT1A5XW4UYhlgrj0lLqjvjOxJxbe5d2FqoJAQGfWqcqBL3mpHyy6IhQnupnoWHCUL53mehBHj/YYtyLeynG6UcLiaFME300wIl/BQGO9LZ4VlQqtcbVAWbVLdqIW672S97sTJ0kjX8D3MsHXolezKUwuBEJeuP6XFQwvkZaCAfqgAt7UnWmxIOQBcXXKBJMK/HceECFooX7ZnprbQ7TGsqhiHwdJXh1Ojk9AtsZi+rsD1bnDJcU= spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: b23e3a1c-6c4c-42ff-04f0-08d61c4a5b01 X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Sep 2018 03:03:12.1184 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR21MB0133 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andreas Gruenbacher [ Upstream commit ebf00be37de35788cad72f4f20b4a39e30c0be4a ] According to xfstest generic/240, applications seem to expect direct I/O writes to either complete as a whole or to fail; short direct I/O writes are apparently not appreciated. This means that when only part of an asynchronous direct I/O write succeeds, we can either fail the entire write, or we can wait for the partial write to complete and retry the remaining write as buffered I/O. The old __blockdev_direct_IO helper has code for waiting for partial writes to complete; the new iomap_dio_rw iomap helper does not. The above mentioned fallback mode is needed for gfs2, which doesn't allow block allocations under direct I/O to avoid taking cluster-wide exclusive locks. As a consequence, an asynchronous direct I/O write to a file range that contains a hole will result in a short write. In that case, wait for the short write to complete to allow gfs2 to recover. Signed-off-by: Andreas Gruenbacher Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Sasha Levin --- fs/iomap.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/fs/iomap.c b/fs/iomap.c index d4801f8dd4fd..8f7673a69273 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -693,6 +693,7 @@ struct iomap_dio { atomic_t ref; unsigned flags; int error; + bool wait_for_completion; =20 union { /* used during submission and for synchronous completion: */ @@ -793,9 +794,8 @@ static void iomap_dio_bio_end_io(struct bio *bio) iomap_dio_set_error(dio, blk_status_to_errno(bio->bi_status)); =20 if (atomic_dec_and_test(&dio->ref)) { - if (is_sync_kiocb(dio->iocb)) { + if (dio->wait_for_completion) { struct task_struct *waiter =3D dio->submit.waiter; - WRITE_ONCE(dio->submit.waiter, NULL); wake_up_process(waiter); } else if (dio->flags & IOMAP_DIO_WRITE) { @@ -980,13 +980,12 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *ite= r, dio->end_io =3D end_io; dio->error =3D 0; dio->flags =3D 0; + dio->wait_for_completion =3D is_sync_kiocb(iocb); =20 dio->submit.iter =3D iter; - if (is_sync_kiocb(iocb)) { - dio->submit.waiter =3D current; - dio->submit.cookie =3D BLK_QC_T_NONE; - dio->submit.last_queue =3D NULL; - } + dio->submit.waiter =3D current; + dio->submit.cookie =3D BLK_QC_T_NONE; + dio->submit.last_queue =3D NULL; =20 if (iov_iter_rw(iter) =3D=3D READ) { if (pos >=3D dio->i_size) @@ -1016,7 +1015,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *ite= r, WARN_ON_ONCE(ret); ret =3D 0; =20 - if (iov_iter_rw(iter) =3D=3D WRITE && !is_sync_kiocb(iocb) && + if (iov_iter_rw(iter) =3D=3D WRITE && !dio->wait_for_completion && !inode->i_sb->s_dio_done_wq) { ret =3D sb_init_dio_done_wq(inode->i_sb); if (ret < 0) @@ -1031,8 +1030,10 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *it= er, iomap_dio_actor); if (ret <=3D 0) { /* magic error code to fall back to buffered I/O */ - if (ret =3D=3D -ENOTBLK) + if (ret =3D=3D -ENOTBLK) { + dio->wait_for_completion =3D true; ret =3D 0; + } break; } pos +=3D ret; @@ -1046,7 +1047,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *ite= r, iomap_dio_set_error(dio, ret); =20 if (!atomic_dec_and_test(&dio->ref)) { - if (!is_sync_kiocb(iocb)) + if (!dio->wait_for_completion) return -EIOCBQUEUED; =20 for (;;) { --=20 2.17.1