From patchwork Sat Aug 31 22:37:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Snitzer X-Patchwork-Id: 13786193 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 8E83318890C; Sat, 31 Aug 2024 22:38:10 +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=1725143890; cv=none; b=h0CgV9sTs5upEqWR6+LvegVATxUPr4jRCN24X6FaJXek1Jn/d30R/an/WdoBBw9RSt79SDxc7us2a+HByY9L9tCkwpeFK5z+VsAo6YZi+p+qnHaVvh9MWUNd57QZStvt6eYU5K5kTIK07YRGb6xkygNXZqoZz0Npr3JvL9jTcsE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725143890; c=relaxed/simple; bh=ewPT2nHxQMEfBBIGXSHmcQYb4XBasbobywAtIkV10Mc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gWC1gXlp+z5wAAxd3zutVOEuIeAIhFsxVoIm53CzC7cNvGQ72fdyoYNaAtYje6wUOEEheT53CKMxuvz+CTslgS5jjCXdcv9u7QUDxawXk/zfnvGShuA0cFN5sFL/1nSZfuHHDOi4A4Tswdo4JWIwEv3PN5mc+uB/IomdelCUdUo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XO8W8K6L; 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="XO8W8K6L" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5106C4CEC4; Sat, 31 Aug 2024 22:38:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725143890; bh=ewPT2nHxQMEfBBIGXSHmcQYb4XBasbobywAtIkV10Mc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XO8W8K6LNDoRHWLBXUB4Ldjquq4O+NTUu0unBEMQMxVVvAolKLoXp+t+n+qIKGd+k LmeDnxR0gsPyxyAAtUie0ZNUQPbDRJqczwdjH6R91SVhCD5yPPf17reWBdfzeSD32Q qRzswtURl8rgAp85R6XMG1DaEXJfsvXZtg+Dpq1zgjzOc26rwfr0b5HSjEJr7m5Tmi 6BEVs32UCl0u5Hx/u97xKACtaSeDqYPjs/pAGeJzkkxOPfgluNYKxCHE5/mArVXm1S QB1bbhGA67/8Z7R9q05m4quYUFZXEVgqyAA4yuWD0d2pO7ou5c43hKMkUouHtO+aPr ZVhnLf8q4dTmw== From: Mike Snitzer To: linux-nfs@vger.kernel.org Cc: Jeff Layton , Chuck Lever , Anna Schumaker , Trond Myklebust , NeilBrown , linux-fsdevel@vger.kernel.org Subject: [PATCH v15 10/26] nfsd: add nfsd_serv_try_get and nfsd_serv_put Date: Sat, 31 Aug 2024 18:37:30 -0400 Message-ID: <20240831223755.8569-11-snitzer@kernel.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240831223755.8569-1-snitzer@kernel.org> References: <20240831223755.8569-1-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 --- fs/nfsd/netns.h | 8 +++++++- fs/nfsd/nfssvc.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 46 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h index 238fc4e56e53..e2d953f21dde 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 nfsd_net *nn); +void nfsd_serv_put(struct nfsd_net *nn); + 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..e43d440f9f0a 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -193,6 +193,30 @@ int nfsd_minorversion(struct nfsd_net *nn, u32 minorversion, enum vers_op change return 0; } +bool nfsd_serv_try_get(struct nfsd_net *nn) +{ + return percpu_ref_tryget_live(&nn->nfsd_serv_ref); +} + +void nfsd_serv_put(struct nfsd_net *nn) +{ + 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 +416,7 @@ 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 +496,13 @@ 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 +627,13 @@ 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);