@@ -125,6 +125,11 @@ 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 const 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;
@@ -172,6 +177,7 @@ 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)
@@ -2389,6 +2395,10 @@ 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, "seconds from last renew: %lld\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);
@@ -4662,6 +4672,33 @@ static void nfsd_break_one_deleg(struct nfs4_delegation *dp)
nfsd4_run_cb(&dp->dl_recall);
}
+/*
+ * This function is called when a file is opened and there is a
+ * delegation conflict with another client. If the other client
+ * is a courtesy client then kick start the laundromat to destroy
+ * it.
+ */
+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);
+
+ if (!i_am_nfsd())
+ goto out;
+ rqst = kthread_data(current);
+ if (rqst->rq_prog != NFS_PROGRAM || rqst->rq_vers < 4)
+ return false;
+out:
+ 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;
+}
+
/* Called from break_lease() with i_lock held. */
static bool
nfsd_break_deleg_cb(struct file_lock *fl)
@@ -4670,6 +4707,8 @@ 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_cb_recall(&dp->dl_stid);
/*
@@ -4912,6 +4951,118 @@ nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh,
return nfsd_setattr(rqstp, fh, &iattr, 0, (time64_t)0);
}
+static bool
+__nfs4_check_deny_bmap(struct nfs4_ol_stateid *stp, u32 access,
+ bool share_access)
+{
+ if (share_access) {
+ if (!stp->st_deny_bmap)
+ return false;
+
+ if ((stp->st_deny_bmap & (1 << NFS4_SHARE_DENY_BOTH)) ||
+ (access & NFS4_SHARE_ACCESS_READ &&
+ stp->st_deny_bmap & (1 << NFS4_SHARE_DENY_READ)) ||
+ (access & NFS4_SHARE_ACCESS_WRITE &&
+ stp->st_deny_bmap & (1 << NFS4_SHARE_DENY_WRITE))) {
+ return true;
+ }
+ return false;
+ }
+ if ((access & NFS4_SHARE_DENY_BOTH) ||
+ (access & NFS4_SHARE_DENY_READ &&
+ stp->st_access_bmap & (1 << NFS4_SHARE_ACCESS_READ)) ||
+ (access & NFS4_SHARE_DENY_WRITE &&
+ stp->st_access_bmap & (1 << NFS4_SHARE_ACCESS_WRITE))) {
+ return true;
+ }
+ return false;
+}
+
+/*
+ * access: if share_access is true then check access mode else check deny mode
+ */
+static bool
+nfs4_check_deny_bmap(struct nfs4_client *clp, struct nfs4_file *fp,
+ struct nfs4_ol_stateid *st, u32 access, bool share_access)
+{
+ int i;
+ struct nfs4_openowner *oo;
+ struct nfs4_stateowner *so, *tmp;
+ struct nfs4_ol_stateid *stp, *stmp;
+
+ spin_lock(&clp->cl_lock);
+ for (i = 0; i < OWNER_HASH_SIZE; i++) {
+ list_for_each_entry_safe(so, tmp, &clp->cl_ownerstr_hashtbl[i],
+ so_strhash) {
+ if (!so->so_is_open_owner)
+ continue;
+ oo = openowner(so);
+ list_for_each_entry_safe(stp, stmp,
+ &oo->oo_owner.so_stateids, st_perstateowner) {
+ if (stp == st || stp->st_stid.sc_file != fp)
+ continue;
+ if (__nfs4_check_deny_bmap(stp, access,
+ share_access)) {
+ spin_unlock(&clp->cl_lock);
+ return true;
+ }
+ }
+ }
+ }
+ spin_unlock(&clp->cl_lock);
+ return false;
+}
+
+/*
+ * Function to check if the nfserr_share_denied error for 'fp' resulted
+ * from conflict with courtesy clients then release their state to resolve
+ * the conflict.
+ *
+ * Function returns:
+ * 0 - no conflict with courtesy clients
+ * >0 - conflict with courtesy clients being resolved in background
+ * return nfserr_jukebox to NFS client
+ */
+static int
+nfs4_destroy_clnts_with_sresv_conflict(struct svc_rqst *rqstp,
+ struct nfs4_file *fp, struct nfs4_ol_stateid *stp,
+ u32 access, bool share_access)
+{
+ int cnt = 0;
+ int async_cnt = 0;
+ bool no_retry = false;
+ struct nfs4_client *cl;
+ struct list_head *pos, *next;
+ struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+
+ spin_lock(&nn->client_lock);
+ list_for_each_safe(pos, next, &nn->client_lru) {
+ cl = list_entry(pos, struct nfs4_client, cl_lru);
+ /*
+ * check all nfs4_ol_stateid of this client
+ * for conflicts with 'access'mode.
+ */
+ if (nfs4_check_deny_bmap(cl, fp, stp, access, share_access)) {
+ if (!test_bit(NFSD4_COURTESY_CLIENT, &cl->cl_flags)) {
+ /* conflict with non-courtesy client */
+ no_retry = true;
+ cnt = 0;
+ goto out;
+ }
+ set_bit(NFSD4_DESTROY_COURTESY_CLIENT, &cl->cl_flags);
+ async_cnt++;
+ }
+ }
+out:
+ spin_unlock(&nn->client_lock);
+ if (async_cnt) {
+ mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
+ if (!no_retry)
+ cnt = async_cnt;
+ }
+ return cnt;
+}
+
static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
struct svc_fh *cur_fh, struct nfs4_ol_stateid *stp,
struct nfsd4_open *open)
@@ -4921,6 +5072,7 @@ static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
int oflag = nfs4_access_to_omode(open->op_share_access);
int access = nfs4_access_to_access(open->op_share_access);
unsigned char old_access_bmap, old_deny_bmap;
+ int cnt = 0;
spin_lock(&fp->fi_lock);
@@ -4931,6 +5083,12 @@ static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
status = nfs4_file_check_deny(fp, open->op_share_deny);
if (status != nfs_ok) {
spin_unlock(&fp->fi_lock);
+ if (status != nfserr_share_denied)
+ goto out;
+ cnt = nfs4_destroy_clnts_with_sresv_conflict(rqstp, fp,
+ stp, open->op_share_deny, false);
+ if (cnt > 0)
+ status = nfserr_jukebox;
goto out;
}
@@ -4938,6 +5096,12 @@ static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
status = nfs4_file_get_access(fp, open->op_share_access);
if (status != nfs_ok) {
spin_unlock(&fp->fi_lock);
+ if (status != nfserr_share_denied)
+ goto out;
+ cnt = nfs4_destroy_clnts_with_sresv_conflict(rqstp, fp,
+ stp, open->op_share_access, true);
+ if (cnt > 0)
+ status = nfserr_jukebox;
goto out;
}
@@ -5572,6 +5736,47 @@ static void nfsd4_ssc_expire_umount(struct nfsd_net *nn)
}
#endif
+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)
{
@@ -5587,7 +5792,9 @@ nfs4_laundromat(struct nfsd_net *nn)
};
struct nfs4_cpntf_state *cps;
copy_stateid_t *cps_t;
+ struct nfs4_stid *stid;
int i;
+ int id;
if (clients_still_reclaiming(nn)) {
lt.new_timeo = 0;
@@ -5608,8 +5815,36 @@ 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. Check again and if
+ * it has no state then expire it.
+ */
+ if (clp->cl_minorversion)
+ continue;
+ }
if (!state_expired(<, clp->cl_time))
break;
+ id = 0;
+ spin_lock(&clp->cl_lock);
+ stid = idr_get_next(&clp->cl_stateids, &id);
+ if (stid && !nfs4_anylock_conflict(clp)) {
+ /* client still has states */
+ spin_unlock(&clp->cl_lock);
+ clp->courtesy_client_expiry =
+ ktime_get_boottime_seconds() + courtesy_client_expiry;
+ set_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags);
+ continue;
+ }
+ spin_unlock(&clp->cl_lock);
+exp_client:
if (mark_client_expired_locked(clp))
continue;
list_add(&clp->cl_lru, &reaplist);
@@ -5689,9 +5924,6 @@ 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)
{
@@ -6496,6 +6728,41 @@ nfs4_transform_lock_offset(struct file_lock *lock)
lock->fl_end = OFFSET_MAX;
}
+/*
+ * If testonly is true then check if the client owns the lock is a
+ * courtesy client. If it is then return that client else return NULL.
+ * If testonly is false then destroy the specified courtesy client.
+ */
+static void *
+nfsd4_fl_expire_lock(void *cfl, bool testonly)
+{
+ struct file_lock *fl;
+ struct nfs4_lockowner *lo;
+ struct nfs4_client *clp;
+ struct nfsd_net *nn;
+
+ if (testonly) {
+ fl = (struct file_lock *)cfl;
+ lo = (struct nfs4_lockowner *)fl->fl_owner;
+ clp = lo->lo_owner.so_client;
+ if (test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags))
+ return clp;
+ return NULL;
+ }
+ clp = (struct nfs4_client *)cfl;
+
+ 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 NULL;
+ }
+ spin_unlock(&nn->client_lock);
+ expire_client(clp);
+ return clp;
+}
+
static fl_owner_t
nfsd4_fl_get_owner(fl_owner_t owner)
{
@@ -6543,6 +6810,7 @@ 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
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 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, NLM LOCK and TEST, and local locks requests with COURTESY_CLIENT, destroys the expired client and all its states then allows the conflicting request to succeed. . detects conflict of LOCK/LOCKT, NLM LOCK and TEST, and local locks requests with 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 | 274 +++++++++++++++++++++++++++++++++++++++++++++++++++- fs/nfsd/state.h | 3 + 2 files changed, 274 insertions(+), 3 deletions(-)