From patchwork Thu Sep 5 19:09:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Snitzer X-Patchwork-Id: 13792896 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 C994618FC92 for ; Thu, 5 Sep 2024 19:10:26 +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=1725563427; cv=none; b=aTVeduMY2haGs2gHYjMFfZzUFLPGfrTTEUH0cI2M+wdTdIKYrvNVKb0sXXxsm9zmA2WeVG2ylWUGtXQCmQ4RTkGqWIe63tR0zRptajPBVrhvVlnR7j3eGmDfmkP/im58xVOmrrkKO7f2MJhY7a+GQASjUaHuNtGqpoMgrub8H7s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725563427; c=relaxed/simple; bh=LA7D+XOiklPnq57sHCti3uXZmp8Q0wMRkn8X3Mkwo7E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=J1nzuYaFvGju3/vWnDrgp0H8KV9/PGsy8utppxju1NX5ROeKL114Ury03sTSN169DimwXaPLncR1mjMmZIrGLfugsVUy7rjAJoXTSmW4rySsfmMieTpbcW4QWCT4PNceP/2pry+e6N/e4koswCKL9ROdphZTRIyXZ1Y0ctme6Rs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KobVZP3S; 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="KobVZP3S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 361A8C4CEC3; Thu, 5 Sep 2024 19:10:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725563426; bh=LA7D+XOiklPnq57sHCti3uXZmp8Q0wMRkn8X3Mkwo7E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KobVZP3SlqvRu0oBPRdUVdTxgKTJaQOCPwSLWUOqPhSzfFCW6y7Sc0D9cOtgJ5ln+ NxZTEzO/0spr8ieL2G1ipJRiSmqWxDqEwJklgDo3L/UuKzHF4qAE5FU+hismlZwR/V iPfVYN+afOFJ6+a8NBSKat0VrrfU+mftopRz/bX5Tqnsjftu35SeLUAH1ZIwAbDwhI Fk8c1u3ucXoLL2ArEFbhLAdjZUlQ623r10a3z4mwBIsYapERH/rLH2X8R4FGO1nEzt F37qGAldjWrJJCoi3vR6VdFPg0NbdBUF+ErCga2sYL4gaY173dXN+9QThMN4onTozw +61gB1f2tlP3Q== From: Mike Snitzer To: linux-nfs@vger.kernel.org Cc: Jeff Layton , Chuck Lever , Anna Schumaker , Trond Myklebust , NeilBrown Subject: [PATCH v16 10/26] nfsd: add nfsd_serv_try_get and nfsd_serv_put Date: Thu, 5 Sep 2024 15:09:44 -0400 Message-ID: <20240905191011.41650-11-snitzer@kernel.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240905191011.41650-1-snitzer@kernel.org> References: <20240905191011.41650-1-snitzer@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Introduce nfsd_serv_try_get and nfsd_serv_put and update the nfsd code to prevent nfsd_destroy_serv from destroying nn->nfsd_serv until any caller of nfsd_serv_try_get releases their reference using nfsd_serv_put. A percpu_ref is used to implement the interlock between nfsd_destroy_serv and any caller of nfsd_serv_try_get. This interlock is needed to properly wait for the completion of client initiated localio calls to nfsd (that are _not_ in the context of nfsd). Signed-off-by: Mike Snitzer Reviewed-by: Chuck Lever Reviewed-by: Jeff Layton Reviewed-by: NeilBrown --- fs/nfsd/netns.h | 8 +++++++- fs/nfsd/nfssvc.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 50 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h index 238fc4e56e53..1b9da8f183e3 100644 --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -13,6 +13,7 @@ #include #include #include +#include #include #include @@ -139,7 +140,9 @@ struct nfsd_net { struct svc_info nfsd_info; #define nfsd_serv nfsd_info.serv - + struct percpu_ref nfsd_serv_ref; + struct completion nfsd_serv_confirm_done; + struct completion nfsd_serv_free_done; /* * clientid and stateid data for construction of net unique COPY @@ -221,6 +224,9 @@ struct nfsd_net { extern bool nfsd_support_version(int vers); extern unsigned int nfsd_net_id; +bool nfsd_serv_try_get(struct net *net); +void nfsd_serv_put(struct net *net); + void nfsd_copy_write_verifier(__be32 verf[2], struct nfsd_net *nn); void nfsd_reset_write_verifier(struct nfsd_net *nn); #endif /* __NFSD_NETNS_H__ */ diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index defc430f912f..307e365798f5 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -193,6 +193,34 @@ int nfsd_minorversion(struct nfsd_net *nn, u32 minorversion, enum vers_op change return 0; } +bool nfsd_serv_try_get(struct net *net) +{ + struct nfsd_net *nn = net_generic(net, nfsd_net_id); + + return (nn && percpu_ref_tryget_live(&nn->nfsd_serv_ref)); +} + +void nfsd_serv_put(struct net *net) +{ + struct nfsd_net *nn = net_generic(net, nfsd_net_id); + + percpu_ref_put(&nn->nfsd_serv_ref); +} + +static void nfsd_serv_done(struct percpu_ref *ref) +{ + struct nfsd_net *nn = container_of(ref, struct nfsd_net, nfsd_serv_ref); + + complete(&nn->nfsd_serv_confirm_done); +} + +static void nfsd_serv_free(struct percpu_ref *ref) +{ + struct nfsd_net *nn = container_of(ref, struct nfsd_net, nfsd_serv_ref); + + complete(&nn->nfsd_serv_free_done); +} + /* * Maximum number of nfsd processes */ @@ -392,6 +420,7 @@ static void nfsd_shutdown_net(struct net *net) lockd_down(net); nn->lockd_up = false; } + percpu_ref_exit(&nn->nfsd_serv_ref); nn->nfsd_net_up = false; nfsd_shutdown_generic(); } @@ -471,6 +500,13 @@ void nfsd_destroy_serv(struct net *net) struct nfsd_net *nn = net_generic(net, nfsd_net_id); struct svc_serv *serv = nn->nfsd_serv; + lockdep_assert_held(&nfsd_mutex); + + percpu_ref_kill_and_confirm(&nn->nfsd_serv_ref, nfsd_serv_done); + wait_for_completion(&nn->nfsd_serv_confirm_done); + wait_for_completion(&nn->nfsd_serv_free_done); + /* percpu_ref_exit is called in nfsd_shutdown_net */ + spin_lock(&nfsd_notifier_lock); nn->nfsd_serv = NULL; spin_unlock(&nfsd_notifier_lock); @@ -595,6 +631,13 @@ int nfsd_create_serv(struct net *net) if (nn->nfsd_serv) return 0; + error = percpu_ref_init(&nn->nfsd_serv_ref, nfsd_serv_free, + 0, GFP_KERNEL); + if (error) + return error; + init_completion(&nn->nfsd_serv_free_done); + init_completion(&nn->nfsd_serv_confirm_done); + if (nfsd_max_blksize == 0) nfsd_max_blksize = nfsd_get_default_max_blksize(); nfsd_reset_versions(nn);