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 <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
fs/nfsd/nfs4callback.c | 25 ++++++++++++++++++----
fs/nfsd/nfs4state.c | 58 +++++++++++++++++++++++++++++++++-----------------
fs/nfsd/state.h | 4 +++-
3 files changed, 62 insertions(+), 25 deletions(-)
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 30a71cb46001..a88a93e09d69 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -933,7 +933,7 @@ 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);
@@ -1011,10 +1011,9 @@ static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
run_nfsd4_cb(cb);
}
-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;
@@ -1032,6 +1031,24 @@ nfsd4_do_callback_rpc(struct work_struct *w)
cb->cb_ops, cb);
}
+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);
+}
+
+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;
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 56ea4f12803e..bdf8ac3393bd 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);
@@ -554,6 +556,8 @@ 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]);
@@ -592,7 +596,7 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv
fh_copy_shallow(&dp->dl_fh, ¤t_fh->fh_handle);
dp->dl_time = 0;
atomic_set(&dp->dl_count, 1);
- INIT_WORK(&dp->dl_recall.cb_work, nfsd4_do_callback_rpc);
+ INIT_WORK(&dp->dl_recall.cb_work, nfsd4_run_cb_recall);
return dp;
}
@@ -640,7 +644,9 @@ 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);
}
@@ -648,14 +654,18 @@ 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;
}
}
@@ -1677,7 +1687,7 @@ static struct nfs4_client *create_client(struct xdr_netobj name,
spin_unlock(&nn->client_lock);
return NULL;
}
- INIT_WORK(&clp->cl_cb_null.cb_work, nfsd4_do_callback_rpc);
+ INIT_WORK(&clp->cl_cb_null.cb_work, nfsd4_run_cb_null);
clp->cl_time = get_seconds();
clear_bit(0, &clp->cl_cb_slot_busy);
copy_verf(clp, verf);
@@ -3079,30 +3089,38 @@ nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type)
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);
}
@@ -3127,11 +3145,11 @@ 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 20857142773f..81b7522e3f67 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -436,7 +436,8 @@ extern struct nfs4_client_reclaim *nfsd4_find_reclaim_client(const char *recdir,
extern __be32 nfs4_check_open_reclaim(clientid_t *clid,
struct nfsd4_compound_state *cstate, struct nfsd_net *nn);
extern int set_callback_cred(void);
-void nfsd4_do_callback_rpc(struct work_struct *w);
+void nfsd4_run_cb_null(struct work_struct *w);
+void nfsd4_run_cb_recall(struct work_struct *w);
extern void nfsd4_probe_callback(struct nfs4_client *clp);
extern void nfsd4_probe_callback_sync(struct nfs4_client *clp);
extern void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *);
@@ -444,6 +445,7 @@ 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
--
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