Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qg0-f41.google.com ([209.85.192.41]:35635 "EHLO mail-qg0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750832AbaFZTOB (ORCPT ); Thu, 26 Jun 2014 15:14:01 -0400 Received: by mail-qg0-f41.google.com with SMTP id i50so3481253qgf.14 for ; Thu, 26 Jun 2014 12:14:00 -0700 (PDT) From: Jeff Layton To: bfields@fieldses.org Cc: linux-nfs@vger.kernel.org Subject: [PATCH v2 010/117] nfsd: Avoid taking state_lock while holding inode lock in nfsd_break_one_deleg Date: Thu, 26 Jun 2014 15:11:50 -0400 Message-Id: <1403810017-16062-11-git-send-email-jlayton@primarydata.com> In-Reply-To: <1403810017-16062-1-git-send-email-jlayton@primarydata.com> References: <1403810017-16062-1-git-send-email-jlayton@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: state_lock is a heavily contended global lock. We don't want to grab that while simultaneously holding the inode->i_lock. Add a new per-nfs4_file lock that we can use to protect the per-nfs4_file delegation list. Hold that while walking the list in the break_deleg callback and queue the workqueue job for each one. The workqueue job can then take the state_lock and do the list manipulations without the i_lock being held prior to starting the rpc call. Signed-off-by: Trond Myklebust Signed-off-by: Jeff Layton --- fs/nfsd/nfs4callback.c | 22 ++++++++++++++++++---- fs/nfsd/nfs4state.c | 43 ++++++++++++++++++++++++++++--------------- fs/nfsd/state.h | 2 ++ 3 files changed, 48 insertions(+), 19 deletions(-) diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c index 00cb9b7a75f6..771323ae1b33 100644 --- a/fs/nfsd/nfs4callback.c +++ b/fs/nfsd/nfs4callback.c @@ -1014,9 +1014,8 @@ static void nfsd4_process_cb_update(struct nfsd4_callback *cb) run_nfsd4_cb(cb); } -static void nfsd4_do_callback_rpc(struct work_struct *w) +static void nfsd4_run_callback_rpc(struct nfsd4_callback *cb) { - struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work); struct nfs4_client *clp = cb->cb_clp; struct rpc_clnt *clnt; @@ -1034,6 +1033,22 @@ static void nfsd4_do_callback_rpc(struct work_struct *w) cb->cb_ops, cb); } +static void nfsd4_do_callback_rpc(struct work_struct *w) +{ + struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, + cb_work); + nfsd4_run_callback_rpc(cb); +} + +static void nfsd4_do_cb_recall(struct work_struct *w) +{ + struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, + cb_work); + + nfsd4_prepare_cb_recall(cb->cb_op); + nfsd4_run_callback_rpc(cb); +} + void nfsd4_cb_recall(struct nfs4_delegation *dp) { struct nfsd4_callback *cb = &dp->dl_recall; @@ -1050,8 +1065,7 @@ void nfsd4_cb_recall(struct nfs4_delegation *dp) INIT_LIST_HEAD(&cb->cb_per_client); cb->cb_done = true; - - INIT_WORK(&cb->cb_work, nfsd4_do_callback_rpc); + INIT_WORK(&cb->cb_work, nfsd4_do_cb_recall); run_nfsd4_cb(&dp->dl_recall); } diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index b49b46b0ce23..461229a01963 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -513,7 +513,9 @@ hash_delegation_locked(struct nfs4_delegation *dp, struct nfs4_file *fp) lockdep_assert_held(&state_lock); dp->dl_stid.sc_type = NFS4_DELEG_STID; + spin_lock(&fp->fi_lock); list_add(&dp->dl_perfile, &fp->fi_delegations); + spin_unlock(&fp->fi_lock); list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations); } @@ -521,14 +523,18 @@ hash_delegation_locked(struct nfs4_delegation *dp, struct nfs4_file *fp) static void unhash_delegation(struct nfs4_delegation *dp) { + struct nfs4_file *fp = dp->dl_file; + spin_lock(&state_lock); list_del_init(&dp->dl_perclnt); - list_del_init(&dp->dl_perfile); list_del_init(&dp->dl_recall_lru); + spin_lock(&fp->fi_lock); + list_del_init(&dp->dl_perfile); + spin_unlock(&fp->fi_lock); spin_unlock(&state_lock); - if (dp->dl_file) { - nfs4_put_deleg_lease(dp->dl_file); - put_nfs4_file(dp->dl_file); + if (fp) { + nfs4_put_deleg_lease(fp); + put_nfs4_file(fp); dp->dl_file = NULL; } } @@ -2612,6 +2618,7 @@ static void nfsd4_init_file(struct nfs4_file *fp, struct inode *ino) lockdep_assert_held(&state_lock); atomic_set(&fp->fi_ref, 1); + spin_lock_init(&fp->fi_lock); INIT_LIST_HEAD(&fp->fi_stateids); INIT_LIST_HEAD(&fp->fi_delegations); ihold(ino); @@ -2857,26 +2864,32 @@ out: return ret; } -static void nfsd_break_one_deleg(struct nfs4_delegation *dp) +void nfsd4_prepare_cb_recall(struct nfs4_delegation *dp) { struct nfs4_client *clp = dp->dl_stid.sc_client; struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id); - lockdep_assert_held(&state_lock); + /* + * We can't do this in nfsd_break_deleg_cb because it is + * already holding inode->i_lock + */ + spin_lock(&state_lock); + if (list_empty(&dp->dl_recall_lru)) { + dp->dl_time = get_seconds(); + list_add_tail(&dp->dl_recall_lru, &nn->del_recall_lru); + } + spin_unlock(&state_lock); +} + +static void nfsd_break_one_deleg(struct nfs4_delegation *dp) +{ /* We're assuming the state code never drops its reference * without first removing the lease. Since we're in this lease * callback (and since the lease code is serialized by the kernel * lock) we know the server hasn't removed the lease yet, we know * it's safe to take a reference: */ atomic_inc(&dp->dl_count); - - list_add_tail(&dp->dl_recall_lru, &nn->del_recall_lru); - - /* Only place dl_time is set; protected by i_lock: */ - dp->dl_time = get_seconds(); - block_delegations(&dp->dl_fh); - nfsd4_cb_recall(dp); } @@ -2901,11 +2914,11 @@ static void nfsd_break_deleg_cb(struct file_lock *fl) */ fl->fl_break_time = 0; - spin_lock(&state_lock); fp->fi_had_conflict = true; + spin_lock(&fp->fi_lock); list_for_each_entry(dp, &fp->fi_delegations, dl_perfile) nfsd_break_one_deleg(dp); - spin_unlock(&state_lock); + spin_unlock(&fp->fi_lock); } static diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h index 9447f86f2778..7d6ba06c1abe 100644 --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -382,6 +382,7 @@ static inline struct nfs4_lockowner * lockowner(struct nfs4_stateowner *so) /* nfs4_file: a file opened by some number of (open) nfs4_stateowners. */ struct nfs4_file { atomic_t fi_ref; + spinlock_t fi_lock; struct hlist_node fi_hash; /* hash by "struct inode *" */ struct list_head fi_stateids; struct list_head fi_delegations; @@ -471,6 +472,7 @@ extern void nfsd4_cb_recall(struct nfs4_delegation *dp); extern int nfsd4_create_callback_queue(void); extern void nfsd4_destroy_callback_queue(void); extern void nfsd4_shutdown_callback(struct nfs4_client *); +extern void nfsd4_prepare_cb_recall(struct nfs4_delegation *dp); extern void nfs4_put_delegation(struct nfs4_delegation *dp); extern struct nfs4_client_reclaim *nfs4_client_to_reclaim(const char *name, struct nfsd_net *nn); -- 1.9.3