From patchwork Thu Nov 14 03:59:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Snitzer X-Patchwork-Id: 13874518 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A07A01E7C2A for ; Thu, 14 Nov 2024 03:59:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731556796; cv=none; b=eEq15w/8bbPnTciH7FUGTlvZFAOQdYNKp0H6azoyzvMrMBRpXeYh6PlHJivPedqdPRYFFegzn7hKmQX5Ml0ud6nNdm1IzRcpmneb9W7XCNKjpgIYJJgF0GHqABWMWv71v/ABtrL6hBtURbJl9bp+wWpkaklAidUkQHP0i0QUiIQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731556796; c=relaxed/simple; bh=mt5l/PhqSR5Fvq/Ed80gzI0rKgUrJu7Xhy5MIy4f/tg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=peIoTo36L5rxxjlIF3BjbLfCA23OC9I0rUdQ67kCse9EMSSxI7cDVvkXgsabxhv86qThK1Apls2T8FvvILcFYx/Qh7xOezbPzrbgM0Htpk4pKfxrFGbM4E5LiXtK8hxnzY7vi7spw6D9QhcLmcekcxRmU/6yLAXlBT+ELLdwDmk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HDxlG8QA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HDxlG8QA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4193BC4CED0; Thu, 14 Nov 2024 03:59:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731556796; bh=mt5l/PhqSR5Fvq/Ed80gzI0rKgUrJu7Xhy5MIy4f/tg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HDxlG8QAQWkdOsgK6B9olIplw7acIIvhfRIEXMAochPai9HnZlSt6J0kmPVgJcG0X QBEfK+AB5lAf/bx8TjH1ydA/2aox4hzShgApheXLvlRAdK5k/QXsLBfAVUN8S0ElOG /0Xxc9CgUpreenbA7OFmUtmPp52Sa90ZWtAH0Z7bpkFWTIW/g4fo43diYCUnXMbwZG 9G4847hPp3nZ+OTuNazlwGshVgqcax85ksgD/psa93zPM6EQBLw39q/Rm9/lnue3mn vPgFPFKolvZWeKYeVV976Tgqxx4Tr4sBLfQsRYypjtjGzAdUF1mBHK+gMdAYFLlDM4 IVnySEhT2NghQ== From: Mike Snitzer To: linux-nfs@vger.kernel.org Cc: Anna Schumaker , Trond Myklebust , Chuck Lever , Jeff Layton , NeilBrown Subject: [for-6.13 PATCH v2 02/15] nfs/localio: add direct IO enablement with sync and async IO support Date: Wed, 13 Nov 2024 22:59:39 -0500 Message-ID: <20241114035952.13889-3-snitzer@kernel.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20241114035952.13889-1-snitzer@kernel.org> References: <20241114035952.13889-1-snitzer@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This commit simply adds the required O_DIRECT plumbing. It doesn't address the fact that NFS doesn't ensure all writes are page aligned (nor device logical block size aligned as required by O_DIRECT). Because NFS will read-modify-write for IO that isn't aligned, LOCALIO will not use O_DIRECT semantics by default if/when an application requests the use of O_DIRECT. Allow the use of O_DIRECT semantics by: 1: Adding a flag to the nfs_pgio_header struct to allow the NFS O_DIRECT layer to signal that O_DIRECT was used by the application 2: Adding a 'localio_O_DIRECT_semantics' NFS module parameter that when enabled will cause LOCALIO to use O_DIRECT semantics (this may cause IO to fail if applications do not properly align their IO). This commit is derived from code developed by Weston Andros Adamson. Signed-off-by: Mike Snitzer --- Documentation/filesystems/nfs/localio.rst | 11 +++ fs/nfs/direct.c | 1 + fs/nfs/localio.c | 93 ++++++++++++++++++++--- include/linux/nfs_xdr.h | 1 + 4 files changed, 96 insertions(+), 10 deletions(-) diff --git a/Documentation/filesystems/nfs/localio.rst b/Documentation/filesystems/nfs/localio.rst index bd1967e2eab32..eb3dc764cfce8 100644 --- a/Documentation/filesystems/nfs/localio.rst +++ b/Documentation/filesystems/nfs/localio.rst @@ -306,6 +306,17 @@ is issuing IO to the underlying local filesystem that it is sharing with the NFS server. See: fs/nfs/localio.c:nfs_local_doio() and fs/nfs/localio.c:nfs_local_commit(). +With normal NFS that makes use of RPC to issue IO to the server, if an +application uses O_DIRECT the NFS client will bypass the pagecache but +the NFS server will not. Because the NFS server's use of buffered IO +affords applications to be less precise with their alignment when +issuing IO to the NFS client. LOCALIO can be configured to use O_DIRECT +semantics by setting the 'localio_O_DIRECT_semantics' nfs module +parameter to Y, e.g.: + echo Y > /sys/module/nfs/parameters/localio_O_DIRECT_semantics +Once enabled, it will cause LOCALIO to use O_DIRECT semantics (this may +cause IO to fail if applications do not properly align their IO). + Security ======== diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 90079ca134dd3..4b92493d6ff0e 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -303,6 +303,7 @@ static void nfs_read_sync_pgio_error(struct list_head *head, int error) static void nfs_direct_pgio_init(struct nfs_pgio_header *hdr) { get_dreq(hdr->dreq); + set_bit(NFS_IOHDR_ODIRECT, &hdr->flags); } static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = { diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c index 4b8618cf114ca..7637786c5cb70 100644 --- a/fs/nfs/localio.c +++ b/fs/nfs/localio.c @@ -35,6 +35,7 @@ struct nfs_local_kiocb { struct bio_vec *bvec; struct nfs_pgio_header *hdr; struct work_struct work; + void (*aio_complete_work)(struct work_struct *); struct nfsd_file *localio; }; @@ -48,6 +49,11 @@ struct nfs_local_fsync_ctx { static bool localio_enabled __read_mostly = true; module_param(localio_enabled, bool, 0644); +static bool localio_O_DIRECT_semantics __read_mostly = false; +module_param(localio_O_DIRECT_semantics, bool, 0644); +MODULE_PARM_DESC(localio_O_DIRECT_semantics, + "LOCALIO will use O_DIRECT semantics to filesystem."); + static inline bool nfs_client_is_local(const struct nfs_client *clp) { return !!test_bit(NFS_CS_LOCAL_IO, &clp->cl_flags); @@ -285,10 +291,19 @@ nfs_local_iocb_alloc(struct nfs_pgio_header *hdr, kfree(iocb); return NULL; } - init_sync_kiocb(&iocb->kiocb, file); + + if (localio_O_DIRECT_semantics && + test_bit(NFS_IOHDR_ODIRECT, &hdr->flags)) { + iocb->kiocb.ki_filp = file; + iocb->kiocb.ki_flags = IOCB_DIRECT; + } else + init_sync_kiocb(&iocb->kiocb, file); + iocb->kiocb.ki_pos = hdr->args.offset; iocb->hdr = hdr; iocb->kiocb.ki_flags &= ~IOCB_APPEND; + iocb->aio_complete_work = NULL; + return iocb; } @@ -343,6 +358,18 @@ nfs_local_pgio_release(struct nfs_local_kiocb *iocb) nfs_local_hdr_release(hdr, hdr->task.tk_ops); } +/* + * Complete the I/O from iocb->kiocb.ki_complete() + * + * Note that this function can be called from a bottom half context, + * hence we need to queue the rpc_call_done() etc to a workqueue + */ +static inline void nfs_local_pgio_aio_complete(struct nfs_local_kiocb *iocb) +{ + INIT_WORK(&iocb->work, iocb->aio_complete_work); + queue_work(nfsiod_workqueue, &iocb->work); +} + static void nfs_local_read_done(struct nfs_local_kiocb *iocb, long status) { @@ -365,6 +392,23 @@ nfs_local_read_done(struct nfs_local_kiocb *iocb, long status) status > 0 ? status : 0, hdr->res.eof); } +static void nfs_local_read_aio_complete_work(struct work_struct *work) +{ + struct nfs_local_kiocb *iocb = + container_of(work, struct nfs_local_kiocb, work); + + nfs_local_pgio_release(iocb); +} + +static void nfs_local_read_aio_complete(struct kiocb *kiocb, long ret) +{ + struct nfs_local_kiocb *iocb = + container_of(kiocb, struct nfs_local_kiocb, kiocb); + + nfs_local_read_done(iocb, ret); + nfs_local_pgio_aio_complete(iocb); /* Calls nfs_local_read_aio_complete_work */ +} + static void nfs_local_call_read(struct work_struct *work) { struct nfs_local_kiocb *iocb = @@ -379,10 +423,10 @@ static void nfs_local_call_read(struct work_struct *work) nfs_local_iter_init(&iter, iocb, READ); status = filp->f_op->read_iter(&iocb->kiocb, &iter); - WARN_ON_ONCE(status == -EIOCBQUEUED); - - nfs_local_read_done(iocb, status); - nfs_local_pgio_release(iocb); + if (status != -EIOCBQUEUED) { + nfs_local_read_done(iocb, status); + nfs_local_pgio_release(iocb); + } revert_creds(save_cred); } @@ -410,6 +454,11 @@ nfs_do_local_read(struct nfs_pgio_header *hdr, nfs_local_pgio_init(hdr, call_ops); hdr->res.eof = false; + if (iocb->kiocb.ki_flags & IOCB_DIRECT) { + iocb->kiocb.ki_complete = nfs_local_read_aio_complete; + iocb->aio_complete_work = nfs_local_read_aio_complete_work; + } + INIT_WORK(&iocb->work, nfs_local_call_read); queue_work(nfslocaliod_workqueue, &iocb->work); @@ -534,6 +583,24 @@ nfs_local_write_done(struct nfs_local_kiocb *iocb, long status) nfs_local_pgio_done(hdr, status); } +static void nfs_local_write_aio_complete_work(struct work_struct *work) +{ + struct nfs_local_kiocb *iocb = + container_of(work, struct nfs_local_kiocb, work); + + nfs_local_vfs_getattr(iocb); + nfs_local_pgio_release(iocb); +} + +static void nfs_local_write_aio_complete(struct kiocb *kiocb, long ret) +{ + struct nfs_local_kiocb *iocb = + container_of(kiocb, struct nfs_local_kiocb, kiocb); + + nfs_local_write_done(iocb, ret); + nfs_local_pgio_aio_complete(iocb); /* Calls nfs_local_write_aio_complete_work */ +} + static void nfs_local_call_write(struct work_struct *work) { struct nfs_local_kiocb *iocb = @@ -552,11 +619,11 @@ static void nfs_local_call_write(struct work_struct *work) file_start_write(filp); status = filp->f_op->write_iter(&iocb->kiocb, &iter); file_end_write(filp); - WARN_ON_ONCE(status == -EIOCBQUEUED); - - nfs_local_write_done(iocb, status); - nfs_local_vfs_getattr(iocb); - nfs_local_pgio_release(iocb); + if (status != -EIOCBQUEUED) { + nfs_local_write_done(iocb, status); + nfs_local_vfs_getattr(iocb); + nfs_local_pgio_release(iocb); + } revert_creds(save_cred); current->flags = old_flags; @@ -592,10 +659,16 @@ nfs_do_local_write(struct nfs_pgio_header *hdr, case NFS_FILE_SYNC: iocb->kiocb.ki_flags |= IOCB_DSYNC|IOCB_SYNC; } + nfs_local_pgio_init(hdr, call_ops); nfs_set_local_verifier(hdr->inode, hdr->res.verf, hdr->args.stable); + if (iocb->kiocb.ki_flags & IOCB_DIRECT) { + iocb->kiocb.ki_complete = nfs_local_write_aio_complete; + iocb->aio_complete_work = nfs_local_write_aio_complete_work; + } + INIT_WORK(&iocb->work, nfs_local_call_write); queue_work(nfslocaliod_workqueue, &iocb->work); diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h index e74a87bb18a44..162b7c0c35557 100644 --- a/include/linux/nfs_xdr.h +++ b/include/linux/nfs_xdr.h @@ -1632,6 +1632,7 @@ enum { NFS_IOHDR_RESEND_PNFS, NFS_IOHDR_RESEND_MDS, NFS_IOHDR_UNSTABLE_WRITES, + NFS_IOHDR_ODIRECT, }; struct nfs_io_completion;