This is a note to let you know that I've just added the patch titled
NFSD: add courteous server support for thread with only delegation
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-add-courteous-server-support-for-thread-with-on.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 455014ab9cabdd870f0e44b267646fe9fe0812a0
Author: Dai Ngo <dai.ngo@xxxxxxxxxx>
Date: Mon May 2 14:19:21 2022 -0700
NFSD: add courteous server support for thread with only delegation
[ Upstream commit 66af25799940b26efd41ea6e648f75c41a48a2c2 ]
This patch provides courteous server support for delegation only.
Only expired client with delegation but no conflict and no open
or lock state is allowed to be in COURTESY state.
Delegation conflict with COURTESY/EXPIRABLE client is resolved by
setting it to EXPIRABLE, queue work for the laundromat and return
delay to the caller. Conflict is resolved when the laudromat runs
and expires the EXIRABLE client while the NFS client retries the
OPEN request. Local thread request that gets conflict is doing the
retry in _break_lease.
Client in COURTESY or EXPIRABLE state is allowed to reconnect and
continues to have access to its state. Access to the nfs4_client by
the reconnecting thread and the laundromat is serialized via the
client_lock.
Reviewed-by: J. Bruce Fields <bfields@xxxxxxxxxxxx>
Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 0170aaf318ea2..74c0a88904047 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -125,6 +125,8 @@ static void free_session(struct nfsd4_session *);
static const struct nfsd4_callback_ops nfsd4_cb_recall_ops;
static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops;
+static struct workqueue_struct *laundry_wq;
+
static bool is_session_dead(struct nfsd4_session *ses)
{
return ses->se_flags & NFS4_SESSION_DEAD;
@@ -152,6 +154,7 @@ static __be32 get_client_locked(struct nfs4_client *clp)
if (is_client_expired(clp))
return nfserr_expired;
atomic_inc(&clp->cl_rpc_users);
+ clp->cl_state = NFSD4_ACTIVE;
return nfs_ok;
}
@@ -172,6 +175,7 @@ renew_client_locked(struct nfs4_client *clp)
list_move_tail(&clp->cl_lru, &nn->client_lru);
clp->cl_time = ktime_get_boottime_seconds();
+ clp->cl_state = NFSD4_ACTIVE;
}
static void put_client_renew_locked(struct nfs4_client *clp)
@@ -1102,6 +1106,7 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_file *fp,
get_clnt_odstate(odstate);
dp->dl_type = NFS4_OPEN_DELEGATE_READ;
dp->dl_retries = 1;
+ dp->dl_recalled = false;
nfsd4_init_cb(&dp->dl_recall, dp->dl_stid.sc_client,
&nfsd4_cb_recall_ops, NFSPROC4_CLNT_CB_RECALL);
get_nfs4_file(fp);
@@ -2017,6 +2022,8 @@ static struct nfs4_client *alloc_client(struct xdr_netobj name)
idr_init(&clp->cl_stateids);
atomic_set(&clp->cl_rpc_users, 0);
clp->cl_cb_state = NFSD4_CB_UNKNOWN;
+ clp->cl_state = NFSD4_ACTIVE;
+ atomic_set(&clp->cl_delegs_in_recall, 0);
INIT_LIST_HEAD(&clp->cl_idhash);
INIT_LIST_HEAD(&clp->cl_openowners);
INIT_LIST_HEAD(&clp->cl_delegations);
@@ -4711,9 +4718,18 @@ nfsd_break_deleg_cb(struct file_lock *fl)
bool ret = false;
struct nfs4_delegation *dp = (struct nfs4_delegation *)fl->fl_owner;
struct nfs4_file *fp = dp->dl_stid.sc_file;
+ struct nfs4_client *clp = dp->dl_stid.sc_client;
+ struct nfsd_net *nn;
trace_nfsd_cb_recall(&dp->dl_stid);
+ dp->dl_recalled = true;
+ atomic_inc(&clp->cl_delegs_in_recall);
+ if (try_to_expire_client(clp)) {
+ nn = net_generic(clp->net, nfsd_net_id);
+ mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
+ }
+
/*
* We don't want the locks code to timeout the lease for us;
* we'll remove it ourself if a delegation isn't returned
@@ -4756,9 +4772,14 @@ static int
nfsd_change_deleg_cb(struct file_lock *onlist, int arg,
struct list_head *dispose)
{
- if (arg & F_UNLCK)
+ struct nfs4_delegation *dp = (struct nfs4_delegation *)onlist->fl_owner;
+ struct nfs4_client *clp = dp->dl_stid.sc_client;
+
+ if (arg & F_UNLCK) {
+ if (dp->dl_recalled)
+ atomic_dec(&clp->cl_delegs_in_recall);
return lease_modify(onlist, arg, dispose);
- else
+ } else
return -EAGAIN;
}
@@ -5622,6 +5643,49 @@ static void nfsd4_ssc_expire_umount(struct nfsd_net *nn)
}
#endif
+/*
+ * place holder for now, no check for lock blockers yet
+ */
+static bool
+nfs4_anylock_blockers(struct nfs4_client *clp)
+{
+ if (atomic_read(&clp->cl_delegs_in_recall) ||
+ client_has_openowners(clp) ||
+ !list_empty(&clp->async_copies))
+ return true;
+ return false;
+}
+
+static void
+nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist,
+ struct laundry_time *lt)
+{
+ struct list_head *pos, *next;
+ struct nfs4_client *clp;
+
+ INIT_LIST_HEAD(reaplist);
+ spin_lock(&nn->client_lock);
+ list_for_each_safe(pos, next, &nn->client_lru) {
+ clp = list_entry(pos, struct nfs4_client, cl_lru);
+ if (clp->cl_state == NFSD4_EXPIRABLE)
+ goto exp_client;
+ if (!state_expired(lt, clp->cl_time))
+ break;
+ if (!atomic_read(&clp->cl_rpc_users))
+ clp->cl_state = NFSD4_COURTESY;
+ if (!client_has_state(clp) ||
+ ktime_get_boottime_seconds() >=
+ (clp->cl_time + NFSD_COURTESY_CLIENT_TIMEOUT))
+ goto exp_client;
+ if (nfs4_anylock_blockers(clp)) {
+exp_client:
+ if (!mark_client_expired_locked(clp))
+ list_add(&clp->cl_lru, reaplist);
+ }
+ }
+ spin_unlock(&nn->client_lock);
+}
+
static time64_t
nfs4_laundromat(struct nfsd_net *nn)
{
@@ -5644,7 +5708,6 @@ nfs4_laundromat(struct nfsd_net *nn)
goto out;
}
nfsd4_end_grace(nn);
- INIT_LIST_HEAD(&reaplist);
spin_lock(&nn->s2s_cp_lock);
idr_for_each_entry(&nn->s2s_cp_stateids, cps_t, i) {
@@ -5654,17 +5717,7 @@ nfs4_laundromat(struct nfsd_net *nn)
_free_cpntf_state_locked(nn, cps);
}
spin_unlock(&nn->s2s_cp_lock);
-
- spin_lock(&nn->client_lock);
- list_for_each_safe(pos, next, &nn->client_lru) {
- clp = list_entry(pos, struct nfs4_client, cl_lru);
- if (!state_expired(<, clp->cl_time))
- break;
- if (mark_client_expired_locked(clp))
- continue;
- list_add(&clp->cl_lru, &reaplist);
- }
- spin_unlock(&nn->client_lock);
+ nfs4_get_client_reaplist(nn, &reaplist, <);
list_for_each_safe(pos, next, &reaplist) {
clp = list_entry(pos, struct nfs4_client, cl_lru);
trace_nfsd_clid_purged(&clp->cl_clientid);
@@ -5739,7 +5792,6 @@ nfs4_laundromat(struct nfsd_net *nn)
return max_t(time64_t, lt.new_timeo, NFSD_LAUNDROMAT_MINTIMEOUT);
}
-static struct workqueue_struct *laundry_wq;
static void laundromat_main(struct work_struct *);
static void
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 4fc1fd639527a..23996c6ca75e3 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -336,6 +336,7 @@ void nfsd_lockd_shutdown(void);
#define COMPOUND_ERR_SLACK_SPACE 16 /* OP_SETATTR */
#define NFSD_LAUNDROMAT_MINTIMEOUT 1 /* seconds */
+#define NFSD_COURTESY_CLIENT_TIMEOUT (24 * 60 * 60) /* seconds */
/*
* The following attributes are currently not supported by the NFSv4 server:
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 95457cfd37fc0..f3d6313914ed0 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -149,6 +149,7 @@ struct nfs4_delegation {
/* For recall: */
int dl_retries;
struct nfsd4_callback dl_recall;
+ bool dl_recalled;
};
#define cb_to_delegation(cb) \
@@ -282,6 +283,28 @@ struct nfsd4_sessionid {
#define HEXDIR_LEN 33 /* hex version of 16 byte md5 of cl_name plus '\0' */
+/*
+ * State Meaning Where set
+ * --------------------------------------------------------------------------
+ * | NFSD4_ACTIVE | Confirmed, active | Default |
+ * |------------------- ----------------------------------------------------|
+ * | NFSD4_COURTESY | Courtesy state. | nfs4_get_client_reaplist |
+ * | | Lease/lock/share | |
+ * | | reservation conflict | |
+ * | | can cause Courtesy | |
+ * | | client to be expired | |
+ * |------------------------------------------------------------------------|
+ * | NFSD4_EXPIRABLE | Courtesy client to be| nfs4_laundromat |
+ * | | expired by Laundromat| try_to_expire_client |
+ * | | due to conflict | |
+ * |------------------------------------------------------------------------|
+ */
+enum {
+ NFSD4_ACTIVE = 0,
+ NFSD4_COURTESY,
+ NFSD4_EXPIRABLE,
+};
+
/*
* struct nfs4_client - one per client. Clientids live here.
*
@@ -385,6 +408,9 @@ struct nfs4_client {
struct list_head async_copies; /* list of async copies */
spinlock_t async_lock; /* lock for async copies */
atomic_t cl_cb_inflight; /* Outstanding callbacks */
+
+ unsigned int cl_state;
+ atomic_t cl_delegs_in_recall;
};
/* struct nfs4_client_reset
@@ -702,4 +728,9 @@ extern void nfsd4_client_record_remove(struct nfs4_client *clp);
extern int nfsd4_client_record_check(struct nfs4_client *clp);
extern void nfsd4_record_grace_done(struct nfsd_net *nn);
+static inline bool try_to_expire_client(struct nfs4_client *clp)
+{
+ cmpxchg(&clp->cl_state, NFSD4_COURTESY, NFSD4_EXPIRABLE);
+ return clp->cl_state == NFSD4_EXPIRABLE;
+}
#endif /* NFSD4_STATE_H */
