@@ -124,6 +124,11 @@ 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 void laundromat_main(struct work_struct *);
+
+static int courtesy_client_expiry = (24 * 60 * 60); /* in secs */
+
static bool is_session_dead(struct nfsd4_session *ses)
{
return ses->se_flags & NFS4_SESSION_DEAD;
@@ -171,6 +176,7 @@ renew_client_locked(struct nfs4_client *clp)
list_move_tail(&clp->cl_lru, &nn->client_lru);
clp->cl_time = ktime_get_boottime_seconds();
+ clear_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags);
}
static void put_client_renew_locked(struct nfs4_client *clp)
@@ -2371,6 +2377,10 @@ static int client_info_show(struct seq_file *m, void *v)
seq_puts(m, "status: confirmed\n");
else
seq_puts(m, "status: unconfirmed\n");
+ seq_printf(m, "courtesy client: %s\n",
+ test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags) ? "yes" : "no");
+ seq_printf(m, "last renew: %lld secs\n",
+ ktime_get_boottime_seconds() - clp->cl_time);
seq_printf(m, "name: ");
seq_quote_mem(m, clp->cl_name.data, clp->cl_name.len);
seq_printf(m, "\nminor version: %d\n", clp->cl_minorversion);
@@ -3538,7 +3548,7 @@ static struct nfsd4_conn *__nfsd4_find_conn(struct svc_xprt *xpt, struct nfsd4_s
}
static __be32 nfsd4_match_existing_connection(struct svc_rqst *rqst,
- struct nfsd4_session *session, u32 req)
+ struct nfsd4_session *session, u32 req, struct nfsd4_conn **conn)
{
struct nfs4_client *clp = session->se_client;
struct svc_xprt *xpt = rqst->rq_xprt;
@@ -3561,6 +3571,8 @@ static __be32 nfsd4_match_existing_connection(struct svc_rqst *rqst,
else
status = nfserr_inval;
spin_unlock(&clp->cl_lock);
+ if (status == nfs_ok && conn)
+ *conn = c;
return status;
}
@@ -3585,8 +3597,16 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
status = nfserr_wrong_cred;
if (!nfsd4_mach_creds_match(session->se_client, rqstp))
goto out;
- status = nfsd4_match_existing_connection(rqstp, session, bcts->dir);
- if (status == nfs_ok || status == nfserr_inval)
+ status = nfsd4_match_existing_connection(rqstp, session,
+ bcts->dir, &conn);
+ if (status == nfs_ok) {
+ if (bcts->dir == NFS4_CDFC4_FORE_OR_BOTH ||
+ bcts->dir == NFS4_CDFC4_BACK)
+ conn->cn_flags |= NFS4_CDFC4_BACK;
+ nfsd4_probe_callback(session->se_client);
+ goto out;
+ }
+ if (status == nfserr_inval)
goto out;
status = nfsd4_map_bcts_dir(&bcts->dir);
if (status)
@@ -4610,6 +4630,42 @@ static void nfsd_break_one_deleg(struct nfs4_delegation *dp)
nfsd4_run_cb(&dp->dl_recall);
}
+/*
+ * If the conflict happens due to a NFSv4 request then check for
+ * courtesy client and set rq_conflict_client so that upper layer
+ * can destroy the conflict client and retry the call.
+ */
+static bool
+nfsd_check_courtesy_client(struct nfs4_delegation *dp)
+{
+ struct svc_rqst *rqst;
+ struct nfs4_client *clp = dp->dl_recall.cb_clp;
+ struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+ bool ret = false;
+
+ if (!i_am_nfsd()) {
+ if (test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags)) {
+ set_bit(NFSD4_DESTROY_COURTESY_CLIENT, &clp->cl_flags);
+ mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
+ return true;
+ }
+ return false;
+ }
+ rqst = kthread_data(current);
+ if (rqst->rq_prog != NFS_PROGRAM || rqst->rq_vers < 4)
+ return false;
+ rqst->rq_conflict_client = NULL;
+
+ spin_lock(&nn->client_lock);
+ if (test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags) &&
+ !mark_client_expired_locked(clp)) {
+ rqst->rq_conflict_client = clp;
+ ret = true;
+ }
+ spin_unlock(&nn->client_lock);
+ return ret;
+}
+
/* Called from break_lease() with i_lock held. */
static bool
nfsd_break_deleg_cb(struct file_lock *fl)
@@ -4618,6 +4674,8 @@ nfsd_break_deleg_cb(struct file_lock *fl)
struct nfs4_delegation *dp = (struct nfs4_delegation *)fl->fl_owner;
struct nfs4_file *fp = dp->dl_stid.sc_file;
+ if (nfsd_check_courtesy_client(dp))
+ return false;
trace_nfsd_deleg_break(&dp->dl_stid.sc_stateid);
/*
@@ -5237,6 +5295,22 @@ static void nfsd4_deleg_xgrade_none_ext(struct nfsd4_open *open,
*/
}
+static bool
+nfs4_destroy_courtesy_client(struct nfs4_client *clp)
+{
+ struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+ spin_lock(&nn->client_lock);
+ if (!test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags) ||
+ mark_client_expired_locked(clp)) {
+ spin_unlock(&nn->client_lock);
+ return false;
+ }
+ spin_unlock(&nn->client_lock);
+ expire_client(clp);
+ return true;
+}
+
__be32
nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
{
@@ -5286,7 +5360,13 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
goto out;
}
} else {
+ rqstp->rq_conflict_client = NULL;
status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open);
+ if (status == nfserr_jukebox && rqstp->rq_conflict_client) {
+ if (nfs4_destroy_courtesy_client(rqstp->rq_conflict_client))
+ status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open);
+ }
+
if (status) {
stp->st_stid.sc_type = NFS4_CLOSED_STID;
release_open_stateid(stp);
@@ -5457,6 +5537,47 @@ static bool state_expired(struct laundry_time *lt, time64_t last_refresh)
return false;
}
+static
+bool nfs4_anylock_conflict(struct nfs4_client *clp)
+{
+ int i;
+ struct nfs4_stateowner *so, *tmp;
+ struct nfs4_lockowner *lo;
+ struct nfs4_ol_stateid *stp;
+ struct nfs4_file *nf;
+ struct inode *ino;
+ struct file_lock_context *ctx;
+ struct file_lock *fl;
+
+ for (i = 0; i < OWNER_HASH_SIZE; i++) {
+ /* scan each lock owner */
+ list_for_each_entry_safe(so, tmp, &clp->cl_ownerstr_hashtbl[i],
+ so_strhash) {
+ if (so->so_is_open_owner)
+ continue;
+
+ /* scan lock states of this lock owner */
+ lo = lockowner(so);
+ list_for_each_entry(stp, &lo->lo_owner.so_stateids,
+ st_perstateowner) {
+ nf = stp->st_stid.sc_file;
+ ino = nf->fi_inode;
+ ctx = ino->i_flctx;
+ if (!ctx)
+ continue;
+ /* check each lock belongs to this lock state */
+ list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
+ if (fl->fl_owner != lo)
+ continue;
+ if (!list_empty(&fl->fl_blocked_requests))
+ return true;
+ }
+ }
+ }
+ }
+ return false;
+}
+
static time64_t
nfs4_laundromat(struct nfsd_net *nn)
{
@@ -5472,7 +5593,9 @@ nfs4_laundromat(struct nfsd_net *nn)
};
struct nfs4_cpntf_state *cps;
copy_stateid_t *cps_t;
+ struct nfs4_stid *stid;
int i;
+ int id = 0;
if (clients_still_reclaiming(nn)) {
lt.new_timeo = 0;
@@ -5493,8 +5616,34 @@ nfs4_laundromat(struct nfsd_net *nn)
spin_lock(&nn->client_lock);
list_for_each_safe(pos, next, &nn->client_lru) {
clp = list_entry(pos, struct nfs4_client, cl_lru);
+ if (test_bit(NFSD4_DESTROY_COURTESY_CLIENT, &clp->cl_flags)) {
+ clear_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags);
+ goto exp_client;
+ }
+ if (test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags)) {
+ if (ktime_get_boottime_seconds() >= clp->courtesy_client_expiry)
+ goto exp_client;
+ /*
+ * after umount, v4.0 client is still
+ * around waiting to be expired
+ */
+ if (clp->cl_minorversion)
+ continue;
+ }
if (!state_expired(<, clp->cl_time))
break;
+
+ spin_lock(&clp->cl_lock);
+ stid = idr_get_next(&clp->cl_stateids, &id);
+ spin_unlock(&clp->cl_lock);
+ if (stid && !nfs4_anylock_conflict(clp)) {
+ /* client still has states */
+ clp->courtesy_client_expiry =
+ ktime_get_boottime_seconds() + courtesy_client_expiry;
+ set_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags);
+ continue;
+ }
+exp_client:
if (mark_client_expired_locked(clp)) {
trace_nfsd_clid_expired(&clp->cl_clientid);
continue;
@@ -5572,9 +5721,6 @@ 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
laundromat_main(struct work_struct *laundry)
{
@@ -6393,6 +6539,19 @@ nfs4_transform_lock_offset(struct file_lock *lock)
lock->fl_end = OFFSET_MAX;
}
+/* return true if lock was expired else return false */
+static bool
+nfsd4_fl_expire_lock(struct file_lock *fl, bool testonly)
+{
+ struct nfs4_lockowner *lo = (struct nfs4_lockowner *)fl->fl_owner;
+ struct nfs4_client *clp = lo->lo_owner.so_client;
+
+ if (testonly)
+ return test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags) ?
+ true : false;
+ return nfs4_destroy_courtesy_client(clp);
+}
+
static fl_owner_t
nfsd4_fl_get_owner(fl_owner_t owner)
{
@@ -6438,6 +6597,7 @@ static const struct lock_manager_operations nfsd_posix_mng_ops = {
.lm_notify = nfsd4_lm_notify,
.lm_get_owner = nfsd4_fl_get_owner,
.lm_put_owner = nfsd4_fl_put_owner,
+ .lm_expire_lock = nfsd4_fl_expire_lock,
};
static inline void
@@ -345,6 +345,8 @@ struct nfs4_client {
#define NFSD4_CLIENT_UPCALL_LOCK (5) /* upcall serialization */
#define NFSD4_CLIENT_CB_FLAG_MASK (1 << NFSD4_CLIENT_CB_UPDATE | \
1 << NFSD4_CLIENT_CB_KILL)
+#define NFSD4_COURTESY_CLIENT (6) /* be nice to expired client */
+#define NFSD4_DESTROY_COURTESY_CLIENT (7)
unsigned long cl_flags;
const struct cred *cl_cb_cred;
struct rpc_clnt *cl_cb_client;
@@ -385,6 +387,7 @@ 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 */
+ int courtesy_client_expiry;
};
/* struct nfs4_client_reset
@@ -304,6 +304,7 @@ struct svc_rqst {
* net namespace
*/
void ** rq_lease_breaker; /* The v4 client breaking a lease */
+ void *rq_conflict_client;
};
#define SVC_NET(rqst) (rqst->rq_xprt ? rqst->rq_xprt->xpt_net : rqst->rq_bc_net)
Currently an NFSv4 client must maintain its lease by using the at least one of the state tokens or if nothing else, by issuing a RENEW (4.0), or a singleton SEQUENCE (4.1) at least once during each lease period. If the client fails to renew the lease, for any reason, the Linux server expunges the state tokens immediately upon detection of the "failure to renew the lease" condition and begins returning NFS4ERR_EXPIRED if the client should reconnect and attempt to use the (now) expired state. The default lease period for the Linux server is 90 seconds. The typical client cuts that in half and will issue a lease renewing operation every 45 seconds. The 90 second lease period is very short considering the potential for moderately long term network partitions. A network partition refers to any loss of network connectivity between the NFS client and the NFS server, regardless of its root cause. This includes NIC failures, NIC driver bugs, network misconfigurations & administrative errors, routers & switches crashing and/or having software updates applied, even down to cables being physically pulled. In most cases, these network failures are transient, although the duration is unknown. A server which does not immediately expunge the state on lease expiration is known as a Courteous Server. A Courteous Server continues to recognize previously generated state tokens as valid until conflict arises between the expired state and the requests from another client, or the server reboots. The initial implementation of the Courteous Server will do the following: . when the laundromat thread detects an expired client and if that client still has established states on the Linux server and there is no waiters for the client's locks then mark the client as a COURTESY_CLIENT and skip destroying the client and all its states, otherwise destroy the client as usual. . detects conflict of OPEN request with a COURTESY_CLIENT, destroys the expired client and all its states, skips the delegation recall then allows the conflicting request to succeed. . detects conflict of LOCK/LOCKT request with a COURTESY_CLIENT, destroys the expired client and all its states then allows the conflicting request to succeed. Signed-off-by: Dai Ngo <dai.ngo@oracle.com> --- fs/nfsd/nfs4state.c | 172 +++++++++++++++++++++++++++++++++++++++++++-- fs/nfsd/state.h | 3 + include/linux/sunrpc/svc.h | 1 + 3 files changed, 170 insertions(+), 6 deletions(-)