Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qa0-f45.google.com ([209.85.216.45]:56148 "EHLO mail-qa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754474AbaGHSEl (ORCPT ); Tue, 8 Jul 2014 14:04:41 -0400 Received: by mail-qa0-f45.google.com with SMTP id s7so1164787qap.4 for ; Tue, 08 Jul 2014 11:04:40 -0700 (PDT) From: Jeff Layton To: bfields@fieldses.org Cc: linux-nfs@vger.kernel.org Subject: [PATCH v4 004/100] nfsd: Avoid taking state_lock while holding inode lock in nfsd_break_one_deleg Date: Tue, 8 Jul 2014 14:02:52 -0400 Message-Id: <1404842668-22521-5-git-send-email-jlayton@primarydata.com> In-Reply-To: <1404842668-22521-1-git-send-email-jlayton@primarydata.com> References: <1404842668-22521-1-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 Reviewed-by: Christoph Hellwig --- fs/nfsd/nfs4callback.c | 28 +++++++++++++++++++------- fs/nfsd/nfs4state.c | 53 +++++++++++++++++++++++++++++++++----------------- fs/nfsd/state.h | 2 ++ 3 files changed, 58 insertions(+), 25 deletions(-) diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c index 00cb9b7a75f6..cba4ca375f5e 100644 --- a/fs/nfsd/nfs4callback.c +++ b/fs/nfsd/nfs4callback.c @@ -43,7 +43,7 @@ #define NFSDDBG_FACILITY NFSDDBG_PROC static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason); -static void nfsd4_do_callback_rpc(struct work_struct *w); +static void nfsd4_run_cb_null(struct work_struct *w); #define NFSPROC4_CB_NULL 0 #define NFSPROC4_CB_COMPOUND 1 @@ -764,7 +764,7 @@ static void do_probe_callback(struct nfs4_client *clp) cb->cb_ops = &nfsd4_cb_probe_ops; - INIT_WORK(&cb->cb_work, nfsd4_do_callback_rpc); + INIT_WORK(&cb->cb_work, nfsd4_run_cb_null); run_nfsd4_cb(cb); } @@ -936,7 +936,7 @@ void nfsd4_shutdown_callback(struct nfs4_client *clp) set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags); /* * Note this won't actually result in a null callback; - * instead, nfsd4_do_callback_rpc() will detect the killed + * instead, nfsd4_run_cb_null() will detect the killed * client, destroy the rpc client, and stop: */ do_probe_callback(clp); @@ -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_run_cb_null(struct work_struct *w) +{ + struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, + cb_work); + nfsd4_run_callback_rpc(cb); +} + +static void nfsd4_run_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_run_cb_recall); run_nfsd4_cb(&dp->dl_recall); } diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 15d59e063885..b77e34aca8bf 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -254,6 +254,8 @@ static void nfsd4_free_file(struct nfs4_file *f) static inline void put_nfs4_file(struct nfs4_file *fi) { + might_lock(&state_lock); + if (atomic_dec_and_lock(&fi->fi_ref, &state_lock)) { hlist_del(&fi->fi_hash); spin_unlock(&state_lock); @@ -446,6 +448,8 @@ static void block_delegations(struct knfsd_fh *fh) u32 hash; struct bloom_pair *bd = &blocked_delegations; + lockdep_assert_held(&state_lock); + hash = arch_fast_hash(&fh->fh_base, fh->fh_size, 0); __set_bit(hash&255, bd->set[bd->new]); @@ -532,7 +536,9 @@ 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); } @@ -540,15 +546,19 @@ 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); dp->dl_stid.sc_type = NFS4_CLOSED_DELEG_STID; 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; } } @@ -2671,6 +2681,7 @@ 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); @@ -2921,30 +2932,36 @@ 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'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); - + /* + * We can't do this in nfsd_break_deleg_cb because it is + * already holding inode->i_lock + */ + spin_lock(&state_lock); + block_delegations(&dp->dl_fh); /* * If the dl_time != 0, then we know that it has already been * queued for a lease break. Don't queue it again. */ if (dp->dl_time == 0) { - list_add_tail(&dp->dl_recall_lru, &nn->del_recall_lru); dp->dl_time = get_seconds(); + list_add_tail(&dp->dl_recall_lru, &nn->del_recall_lru); } + spin_unlock(&state_lock); +} - block_delegations(&dp->dl_fh); - +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); nfsd4_cb_recall(dp); } @@ -2969,11 +2986,11 @@ 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 0776e7c4c10a..1ba175ce3d09 100644 --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -378,6 +378,7 @@ 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; @@ -468,6 +469,7 @@ 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