From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66372C433F5 for ; Fri, 25 Feb 2022 03:45:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236474AbiBYDpe (ORCPT ); Thu, 24 Feb 2022 22:45:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237170AbiBYDpa (ORCPT ); Thu, 24 Feb 2022 22:45:30 -0500 Received: from mailout3.samsung.com (mailout3.samsung.com [203.254.224.33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F9CC2692B0 for ; Thu, 24 Feb 2022 19:44:58 -0800 (PST) Received: from epcas5p3.samsung.com (unknown [182.195.41.41]) by mailout3.samsung.com (KnoxPortal) with ESMTP id 20220225034456epoutp0329fdf89338fbf27666d8718f1f63a297~W6qJJJ9oY0114201142epoutp03B for ; Fri, 25 Feb 2022 03:44:56 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout3.samsung.com 20220225034456epoutp0329fdf89338fbf27666d8718f1f63a297~W6qJJJ9oY0114201142epoutp03B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1645760696; bh=/UO9eDeRsnQ02mI7zvtYj8GHrR3f9M5BXxxiPQPbV80=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=JefR7KCdoc8VYZ/gaDGHtpQ93aksxuZB3AltK9ZrzS4COccgFleZ2IgUqiU5g/XYZ llyjEm/q+BSxGEao4yH9oPfQU6vaOH72a4ytEYQwrlR8PlIrQZxQvZiMGZFBBhVwCt 4iLRXVnfztS7zF7tGnpVqfhKyKRzzcux+8UqDOn4= Received: from epsnrtp4.localdomain (unknown [182.195.42.165]) by epcas5p2.samsung.com (KnoxPortal) with ESMTP id 20220225034455epcas5p26a20b70a651c5c4813b20d1e48f2ba38~W6qIW7Vke0148301483epcas5p2P; Fri, 25 Feb 2022 03:44:55 +0000 (GMT) Received: from epsmges5p1new.samsung.com (unknown [182.195.38.183]) by epsnrtp4.localdomain (Postfix) with ESMTP id 4K4bJ31YBBz4x9Px; Fri, 25 Feb 2022 03:44:51 +0000 (GMT) Received: from epcas5p2.samsung.com ( [182.195.41.40]) by epsmges5p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 26.C9.06423.9A058126; Fri, 25 Feb 2022 12:44:41 +0900 (KST) Received: from epsmtrp2.samsung.com (unknown [182.195.40.14]) by epcas5p1.samsung.com (KnoxPortal) with ESMTPA id 20220224124713epcas5p17e353eef4fb4990f0442bc0614217227~WuaVbgzqc2876728767epcas5p15; Thu, 24 Feb 2022 12:47:13 +0000 (GMT) Received: from epsmgms1p1new.samsung.com (unknown [182.195.42.41]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20220224124713epsmtrp2ee80afa62db594176e0e55aba7521d29~WuaVZNiVv0741907419epsmtrp2H; Thu, 24 Feb 2022 12:47:13 +0000 (GMT) X-AuditID: b6c32a49-b13ff70000001917-22-621850a9e292 Received: from epsmtip2.samsung.com ( [182.195.34.31]) by epsmgms1p1new.samsung.com (Symantec Messaging Gateway) with SMTP id F7.83.29871.15E77126; Thu, 24 Feb 2022 21:47:13 +0900 (KST) Received: from test-zns (unknown [107.110.206.5]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20220224124709epsmtip22be20cc572111b6fe3937746e483cc64~WuaR4KTdj1429314293epsmtip2W; Thu, 24 Feb 2022 12:47:09 +0000 (GMT) Date: Thu, 24 Feb 2022 18:12:13 +0530 From: Nitesh Shetty To: Mikulas Patocka Cc: javier@javigon.com, chaitanyak@nvidia.com, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, dm-devel@redhat.com, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org, axboe@kernel.dk, msnitzer@redhat.com, bvanassche@acm.org, martin.petersen@oracle.com, roland@purestorage.com, hare@suse.de, kbusch@kernel.org, hch@lst.de, Frederick.Knight@netapp.com, zach.brown@ni.com, osandov@fb.com, lsf-pc@lists.linux-foundation.org, djwong@kernel.org, josef@toxicpanda.com, clm@fb.com, dsterba@suse.com, tytso@mit.edu, jack@suse.com, joshi.k@samsung.com, arnav.dawn@samsung.com Subject: Re: [PATCH v2 08/10] dm: Add support for copy offload. 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Avoid split happening inside dm target. > > Fail early if the request needs split, currently spliting copy > > request is not supported > > > > Signed-off-by: Nitesh Shetty > > If a dm device is reconfigured, you must invalidate all the copy tokens > that are in flight, otherwise they would copy stale data. > > I suggest that you create a global variable "atomic64_t dm_changed". > In nvme_setup_copy_read you copy this variable to the token. > In nvme_setup_copy_write you compare the variable with the value in the > token and fail if there is mismatch. > In dm.c:__bind you increase the variable, so that all the tokens will be > invalidated if a dm table is changed. > > Mikulas > > Yes, you are right about the reconfiguration of dm device. But wouldn't having a single global counter(dm_changed), will invalidate for all in-flight copy IO's across all dm devices. 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Thu, 24 Feb 2022 12:47:09 +0000 (GMT) Date: Thu, 24 Feb 2022 18:12:13 +0530 From: Nitesh Shetty To: Mikulas Patocka Message-ID: <20220224124213.GD9117@test-zns> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA02Te0xTVxzHPfe2txe2sgtCOHYwu+qcqBQqDw+LDBN0u5NJGCxjc3FY4IYS Stu0ZRvbxEIhCohIGbPAAsSBBJCJzPCuCo4wBAyMlzIfMECUlzwmg4iylpbF/z6/7/l+f+ec 38khcbtaDo+MlqkZpUwsFRDWrJqbLjtdy4JguPvFaifUdHeRjSruZxLop7kVHD1tHmUjXaae g3rHbJBhNp+NupcTMTRavYahpgs6DJVVtGJoovQXgFI7ujG0OiJCrWszBNK1DABkGNqNmgzt LFR4cZyD0gfrCHRtyoCj0raXGMo63Y+h23mrBLr5oJ+FKlYRSjmzwkGT17864ET39gXQWdpZ Dq0tuseie7vi6OryVIL+rfgknX2nFNCNdzUEndTZitP6hX8IerCzFqMztLMEPT8+xKJrRjI4 9NNr/QR99mo5CLI/GrNfwogjGSWfkUXII6NlUb6CgJAw/zAvb3eRq8gH7RPwZeJYxldw8OMg 1w+ipcb5CPhfi6VxRilIrFIJ3N7fr5THqRm+RK5S+woYRaRU4akQqsSxqjhZlFDGqN8Tubvv 9TIaj8dI9IX5hGLutW/L12ZZGjBslQasSEh5wtTkK3gasCbtqEYAl3MGOeZiAcD56ny2uVgC sGS6gL0ReZyYaHEZACzUbuQfAViZVIibXCzqHbhWWmZMkCRB7YYda6RJtqdc4J8/T693xakh FtQPjnBMC5spP5iyXLnu51J7YP7tfSaZS9nC9twxlomtqC9hT3bSOjtQ2+CNmjbM1AdSf1vB 56VduPl0B2HeTC3HzJvhZNtVC/Pg4qyBMAfSjRftfGhJ6wHUntMSZpcf7Gl6gZkYpySwPnfZ knaGObd+teg2MOP5GGbWubCuYIO3wUuXiyx9tsCBfxMtTMOugReWQfZjcPxSDXEObM175Xp5 r+xn5j2wqHGByDNOA6fehKUvSTO6wMsNbkWAXQ62MApVbBSj8lKIZMw3/795hDy2Gqz/oF0f 1YH7w3PCFoCRoAVAEhfYc0dPOIbbcSPF8d8xSnmYMk7KqFqAl/G1snCeQ4Tc+AVl6jCRp4+7 p7e3t6ePh7dI4MjtiKoS21FRYjUTwzAKRrmRw0grngb7vim44Nlhh5lNkpPVy4tdQ0fC39bU Vcyzy/x5xVd+rPyMHMvzCPV7qww4f5F67K+SUxUrtavRwY+SNSE2Hk47HlhnvhESmLYpfqq9 JKZYZ5OZuzLhc+yH7fIbRw9P+iz87uoRv5iTIDTY3nOK1tpmR/g69JGC+ltVd6rCCkLttzZr Pm1IlYghKyPpyYdnNWqH84su+sejBzbxczo0oER++pTOOuW6UFAXKnJOiB14knyI07Dj4fmI pHcDhMfx4cDF7J1/uDS/nrwUFHgBtC/0HAmdomB6Pe32bODzib5pXa+ddPsJ5pOEejJ4SaFr 3uvfPXBmitcZ4jznODTtqq+05c8LWCqJWLQLV6rE/wGLOMDxygQAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrCIsWRmVeSWpSXmKPExsWy7bCSvG5gnXiSQcd3RYs9Nz+zWqy+289m Me3DT2aL9wcfs1pM6p/BbnH5CZ/F3nezWS0u/Ghksni86T+TxZ5Fk5gsVq4+ymTxfPliRovO 0xeYLP48NLQ4+v8tm8WkQ9cYLfbe0rbYs/cki8X8ZU/ZLbqv72Cz2Pd6L7PF8uP/mCwmdlxl sjg36w+bxeF7V1ksVv+xsGjt+clu8Wp/nIOMx+Ur3h4Tm9+xezQvuMPicflsqcemVZ1sHpuX 1HtMvrGc0WP3zQY2j6YzR5k9Znz6wuZx/cx2Jo/e5ndsHh+f3mLx2Pawl93j/b6rbB59W1Yx BohEcdmkpOZklqUW6dslcGWs77zAXLCBs+LWSssGxp3sXYycHBICJhIvGhvBbCGB3YwSUz7r Q8QlJZb9PcIMYQtLrPz3HKiGC6jmCaPEyXdPmEASLAKqEv+Xr2TtYuTgYBPQljj9nwMkLCKg KXFpzhtWkHpmgTssErv+PAMbJCxgL9H6Yy1YPa+AjsTsc+YQM68ySWzcPIMRpIZXQFDi5Mwn LCA2s4CWxI1/L5lA6pkFpCWW/wObzykQLXFxchNYiaiAssSBbceZJjAKzkLSPQtJ9yyE7gWM zKsYJVMLinPTc4sNCwzzUsv1ihNzi0vz0vWS83M3MYIThpbmDsbtqz7oHWJk4mA8xCjBwawk wmtaKJYkxJuSWFmVWpQfX1Sak1p8iFGag0VJnPdC18l4IYH0xJLU7NTUgtQimCwTB6dUA1Nt Rhj70op5z0xtc6esmRqwSjwgbqXToigz7esFRfMLY3ddqhN4kfC4L+T/MkUjW5GwS4c5Td2X bqxtY6413Bx5a7WgwUvdb6sfM98L3dgUbn/g/YXXfAWT3kzKe35tu5+27S/d0zclvzi/Eg1R dji5VrU+2Nbc+4Fawv73pyVPu97awP/lYH0RA8vVD5uMM2ZVzD3/IqWnepOsWkeM7OnrMco8 OjzhOfnHFzWmPrPzFFypedbRa2+l8eU/7309zA683Dqh64bofvlLi5fxfvKQiDPLtjHtrvvu al5VuvPVG69VEhOKgx+rars5FFfxT1566u+8t7q3C4y/TPZ/fPx84MM9s4KkHuxdyT5F0FyJ pTgj0VCLuag4EQCXTrmYhwMAAA== X-CMS-MailID: 20220224124713epcas5p17e353eef4fb4990f0442bc0614217227 X-Msg-Generator: CA X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20220207141948epcas5p4534f6bdc5a1e2e676d7d09c04f8b4a5b References: <20220207141348.4235-1-nj.shetty@samsung.com> <20220207141348.4235-9-nj.shetty@samsung.com> X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 X-loop: dm-devel@redhat.com X-Mailman-Approved-At: Mon, 28 Feb 2022 01:25:13 -0500 Cc: djwong@kernel.org, linux-nvme@lists.infradead.org, clm@fb.com, dm-devel@redhat.com, osandov@fb.com, javier@javigon.com, bvanassche@acm.org, linux-scsi@vger.kernel.org, hch@lst.de, roland@purestorage.com, zach.brown@ni.com, chaitanyak@nvidia.com, msnitzer@redhat.com, josef@toxicpanda.com, linux-block@vger.kernel.org, dsterba@suse.com, kbusch@kernel.org, Frederick.Knight@netapp.com, axboe@kernel.dk, tytso@mit.edu, joshi.k@samsung.com, martin.petersen@oracle.com, arnav.dawn@samsung.com, jack@suse.com, linux-fsdevel@vger.kernel.org, lsf-pc@lists.linux-foundation.org Subject: Re: [dm-devel] [PATCH v2 08/10] dm: Add support for copy offload. X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/mixed; boundary="----.rW42XXn7_Ji6OxwuAF4RAMbP.qed.OeqKlvEhSLhB3noATS=_b2668_" ------.rW42XXn7_Ji6OxwuAF4RAMbP.qed.OeqKlvEhSLhB3noATS=_b2668_ Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline On Wed, Feb 16, 2022 at 08:51:08AM -0500, Mikulas Patocka wrote: > > > On Mon, 7 Feb 2022, Nitesh Shetty wrote: > > > Before enabling copy for dm target, check if underlaying devices and > > dm target support copy. Avoid split happening inside dm target. > > Fail early if the request needs split, currently spliting copy > > request is not supported > > > > Signed-off-by: Nitesh Shetty > > If a dm device is reconfigured, you must invalidate all the copy tokens > that are in flight, otherwise they would copy stale data. > > I suggest that you create a global variable "atomic64_t dm_changed". > In nvme_setup_copy_read you copy this variable to the token. > In nvme_setup_copy_write you compare the variable with the value in the > token and fail if there is mismatch. > In dm.c:__bind you increase the variable, so that all the tokens will be > invalidated if a dm table is changed. > > Mikulas > > Yes, you are right about the reconfiguration of dm device. But wouldn't having a single global counter(dm_changed), will invalidate for all in-flight copy IO's across all dm devices. Is my understanding correct? -- Nitesh Shetty ------.rW42XXn7_Ji6OxwuAF4RAMbP.qed.OeqKlvEhSLhB3noATS=_b2668_ Content-Type: text/plain; charset="utf-8" ------.rW42XXn7_Ji6OxwuAF4RAMbP.qed.OeqKlvEhSLhB3noATS=_b2668_ Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel ------.rW42XXn7_Ji6OxwuAF4RAMbP.qed.OeqKlvEhSLhB3noATS=_b2668_--