From patchwork Thu Sep 8 22:14:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 12970734 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 2A118C38145 for ; Thu, 8 Sep 2022 22:14:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229685AbiIHWOG (ORCPT ); Thu, 8 Sep 2022 18:14:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229607AbiIHWOF (ORCPT ); Thu, 8 Sep 2022 18:14:05 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 641C01098E6 for ; Thu, 8 Sep 2022 15:14:04 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 22B7AB822A4 for ; Thu, 8 Sep 2022 22:14:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D80D0C433D7 for ; Thu, 8 Sep 2022 22:14:01 +0000 (UTC) Subject: [PATCH v4 4/8] NFSD: Add a mechanism to wait for a DELEGRETURN From: Chuck Lever To: linux-nfs@vger.kernel.org Date: Thu, 08 Sep 2022 18:14:00 -0400 Message-ID: <166267524093.1842.15758313847137747406.stgit@manet.1015granger.net> In-Reply-To: <166267495153.1842.14474564029477470642.stgit@manet.1015granger.net> References: <166267495153.1842.14474564029477470642.stgit@manet.1015granger.net> User-Agent: StGit/1.5.dev2+g9ce680a5 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Subsequent patches will use this mechanism to wake up an operation that is waiting for a client to return a delegation. The new tracepoint records whether the wait timed out or was properly awoken by the expected DELEGRETURN: nfsd-1155 [002] 83799.493199: nfsd_delegret_wakeup: xid=0x14b7d6ef fh_hash=0xf6826792 (timed out) Suggested-by: Jeff Layton Signed-off-by: Chuck Lever --- fs/nfsd/nfs4state.c | 30 ++++++++++++++++++++++++++++++ fs/nfsd/nfsd.h | 7 +++++++ fs/nfsd/trace.h | 23 +++++++++++++++++++++++ 3 files changed, 60 insertions(+) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 561f3556b1d2..54bc70427ce3 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4717,6 +4717,35 @@ nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type) return ret; } +static bool nfsd4_deleg_present(const struct inode *inode) +{ + struct file_lock_context *ctx = smp_load_acquire(&inode->i_flctx); + + return ctx && !list_empty_careful(&ctx->flc_lease); +} + +/** + * nfsd_wait_for_delegreturn - wait for delegations to be returned + * @rqstp: the RPC transaction being executed + * @inode: in-core inode of the file being waited for + * + * The timeout prevents deadlock if all nfsd threads happen to be + * tied up waiting for returning delegations. + * + * Return values: + * %true: delegation was returned + * %false: timed out waiting for delegreturn + */ +bool nfsd_wait_for_delegreturn(struct svc_rqst *rqstp, struct inode *inode) +{ + long __maybe_unused timeo; + + timeo = wait_var_event_timeout(inode, !nfsd4_deleg_present(inode), + NFSD_DELEGRETURN_TIMEOUT); + trace_nfsd_delegret_wakeup(rqstp, inode, timeo); + return timeo > 0; +} + static void nfsd4_cb_recall_prepare(struct nfsd4_callback *cb) { struct nfs4_delegation *dp = cb_to_delegation(cb); @@ -6779,6 +6808,7 @@ nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, if (status) goto put_stateid; + wake_up_var(d_inode(cstate->current_fh.fh_dentry)); destroy_delegation(dp); put_stateid: nfs4_put_stid(&dp->dl_stid); diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h index 57a468ed85c3..6ab4ad41ae84 100644 --- a/fs/nfsd/nfsd.h +++ b/fs/nfsd/nfsd.h @@ -164,6 +164,7 @@ char * nfs4_recoverydir(void); bool nfsd4_spo_must_allow(struct svc_rqst *rqstp); int nfsd4_create_laundry_wq(void); void nfsd4_destroy_laundry_wq(void); +bool nfsd_wait_for_delegreturn(struct svc_rqst *rqstp, struct inode *inode); #else static inline int nfsd4_init_slabs(void) { return 0; } static inline void nfsd4_free_slabs(void) { } @@ -179,6 +180,11 @@ static inline bool nfsd4_spo_must_allow(struct svc_rqst *rqstp) } static inline int nfsd4_create_laundry_wq(void) { return 0; }; static inline void nfsd4_destroy_laundry_wq(void) {}; +static inline bool nfsd_wait_for_delegreturn(struct svc_rqst *rqstp, + struct inode *inode) +{ + return false; +} #endif /* @@ -343,6 +349,7 @@ void nfsd_lockd_shutdown(void); #define NFSD_COURTESY_CLIENT_TIMEOUT (24 * 60 * 60) /* seconds */ #define NFSD_CLIENT_MAX_TRIM_PER_RUN 128 #define NFS4_CLIENTS_PER_GB 1024 +#define NFSD_DELEGRETURN_TIMEOUT (HZ / 34) /* 30ms */ /* * The following attributes are currently not supported by the NFSv4 server: diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h index ec8e08315779..06a96e955bd0 100644 --- a/fs/nfsd/trace.h +++ b/fs/nfsd/trace.h @@ -538,6 +538,29 @@ DEFINE_NFSD_COPY_ERR_EVENT(clone_file_range_err); #include "filecache.h" #include "vfs.h" +TRACE_EVENT(nfsd_delegret_wakeup, + TP_PROTO( + const struct svc_rqst *rqstp, + const struct inode *inode, + long timeo + ), + TP_ARGS(rqstp, inode, timeo), + TP_STRUCT__entry( + __field(u32, xid) + __field(const void *, inode) + __field(long, timeo) + ), + TP_fast_assign( + __entry->xid = be32_to_cpu(rqstp->rq_xid); + __entry->inode = inode; + __entry->timeo = timeo; + ), + TP_printk("xid=0x%08x inode=%p%s", + __entry->xid, __entry->inode, + __entry->timeo == 0 ? " (timed out)" : "" + ) +); + DECLARE_EVENT_CLASS(nfsd_stateid_class, TP_PROTO(stateid_t *stp), TP_ARGS(stp),