> On Jan 28, 2022, at 2:39 PM, Dai Ngo <dai.ngo@xxxxxxxxxx> wrote:
>
> 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 state on the Linux server and there is no waiters
> for the client's locks then deletes the client persistent record and marks
> the client as COURTESY_CLIENT and skips destroying the client and all of
> state, otherwise destroys the client as usual.
>
> . Client persistent record is added to the client database when the
> courtesy client reconnects and transits to normal client.
>
> . Lock/delegation/share reversation conflict with courtesy client is
> resolved by marking the courtesy client as DESTROY_COURTESY_CLIENT,
> effectively disable it, then allow the current request to proceed
> immediately.
>
> . Courtesy client marked as DESTROY_COURTESY_CLIENT is not allowed to
> reconnect to reuse itsstate. It is expired by the laundromat asynchronously
> in the background.
>
> Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
> ---
> fs/nfsd/nfs4state.c | 454 +++++++++++++++++++++++++++++++++++++++++++++++-----
> fs/nfsd/state.h | 5 +
> 2 files changed, 415 insertions(+), 44 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 1956d377d1a6..b302d857e196 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 const int courtesy_client_expiry = (24 * 60 * 60); /* in secs */
Please make this a macro, not a const variable.
> +
> static bool is_session_dead(struct nfsd4_session *ses)
> {
> return ses->se_flags & NFS4_SESSION_DEAD;
> @@ -1913,14 +1915,37 @@ __find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
>
> static struct nfsd4_session *
> find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
> - __be32 *ret)
> + __be32 *ret, bool *courtesy_clnt)
IMO the new @courtesy_clnt parameter isn't necessary.
Just create a new cl_flag:
+#define NFSD4_COURTESY_CLIENT (6) /* be nice to expired client */
+#define NFSD4_DESTROY_COURTESY_CLIENT (7)
#define NFSD4_CLIENT_PROMOTE_COURTESY (8)
or REHYDRATE_COURTESY some such.
Set that flag and check it once it is safe to call
nfsd4_client_record_create(). That should make this a
much smaller patch. Anything else you can do to break
this patch into smaller ones will help the review
process.
By the way, the new cl_flags you define in fs/nfsd/state.h
need to be named "NFSD4_CLIENT_yyzzy". I think you can
drop the "_CLIENT" suffix for brevity.
> {
> struct nfsd4_session *session;
> __be32 status = nfserr_badsession;
> + struct nfs4_client *clp;
>
> session = __find_in_sessionid_hashtbl(sessionid, net);
> if (!session)
> goto out;
> + clp = session->se_client;
> + if (courtesy_clnt)
> + *courtesy_clnt = false;
> + if (clp) {
> + /* need to sync with thread resolving lock/deleg conflict */
> + spin_lock(&clp->cl_cs_lock);
> + if (test_bit(NFSD4_DESTROY_COURTESY_CLIENT, &clp->cl_flags)) {
> + spin_unlock(&clp->cl_cs_lock);
> + session = NULL;
> + goto out;
> + }
> + if (test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags)) {
> + if (!courtesy_clnt) {
> + spin_unlock(&clp->cl_cs_lock);
> + session = NULL;
> + goto out;
> + }
> + clear_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags);
> + *courtesy_clnt = true;
> + }
> + spin_unlock(&clp->cl_cs_lock);
> + }
> status = nfsd4_get_session_locked(session);
> if (status)
> session = NULL;
> @@ -1990,6 +2015,7 @@ static struct nfs4_client *alloc_client(struct xdr_netobj name)
> INIT_LIST_HEAD(&clp->cl_openowners);
> INIT_LIST_HEAD(&clp->cl_delegations);
> INIT_LIST_HEAD(&clp->cl_lru);
> + INIT_LIST_HEAD(&clp->cl_cs_list);
> INIT_LIST_HEAD(&clp->cl_revoked);
> #ifdef CONFIG_NFSD_PNFS
> INIT_LIST_HEAD(&clp->cl_lo_states);
> @@ -1997,6 +2023,7 @@ static struct nfs4_client *alloc_client(struct xdr_netobj name)
> INIT_LIST_HEAD(&clp->async_copies);
> spin_lock_init(&clp->async_lock);
> spin_lock_init(&clp->cl_lock);
> + spin_lock_init(&clp->cl_cs_lock);
> rpc_init_wait_queue(&clp->cl_cb_waitq, "Backchannel slot table");
> return clp;
> err_no_hashtbl:
> @@ -2394,6 +2421,10 @@ 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);
> @@ -2801,12 +2832,15 @@ add_clp_to_name_tree(struct nfs4_client *new_clp, struct rb_root *root)
> }
>
> static struct nfs4_client *
> -find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
> +find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root,
> + bool *courtesy_client)
> {
> int cmp;
> struct rb_node *node = root->rb_node;
> struct nfs4_client *clp;
>
> + if (courtesy_client)
> + *courtesy_client = false;
> while (node) {
> clp = rb_entry(node, struct nfs4_client, cl_namenode);
> cmp = compare_blob(&clp->cl_name, name);
> @@ -2814,8 +2848,29 @@ find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
> node = node->rb_left;
> else if (cmp < 0)
> node = node->rb_right;
> - else
> + else {
> + /* sync with thread resolving lock/deleg conflict */
> + spin_lock(&clp->cl_cs_lock);
> + if (test_bit(NFSD4_DESTROY_COURTESY_CLIENT,
> + &clp->cl_flags)) {
> + spin_unlock(&clp->cl_cs_lock);
> + return NULL;
> + }
> + if (test_bit(NFSD4_COURTESY_CLIENT,
> + &clp->cl_flags)) {
> + if (!courtesy_client) {
> + set_bit(NFSD4_DESTROY_COURTESY_CLIENT,
> + &clp->cl_flags);
> + spin_unlock(&clp->cl_cs_lock);
> + return NULL;
> + }
> + clear_bit(NFSD4_COURTESY_CLIENT,
> + &clp->cl_flags);
> + *courtesy_client = true;
> + }
> + spin_unlock(&clp->cl_cs_lock);
> return clp;
> + }
> }
> return NULL;
> }
> @@ -2852,15 +2907,38 @@ move_to_confirmed(struct nfs4_client *clp)
> }
>
> static struct nfs4_client *
> -find_client_in_id_table(struct list_head *tbl, clientid_t *clid, bool sessions)
> +find_client_in_id_table(struct list_head *tbl, clientid_t *clid, bool sessions,
> + bool *courtesy_clnt)
> {
> struct nfs4_client *clp;
> unsigned int idhashval = clientid_hashval(clid->cl_id);
>
> + if (courtesy_clnt)
> + *courtesy_clnt = false;
> list_for_each_entry(clp, &tbl[idhashval], cl_idhash) {
> if (same_clid(&clp->cl_clientid, clid)) {
> if ((bool)clp->cl_minorversion != sessions)
> return NULL;
> +
> + /* need to sync with thread resolving lock/deleg conflict */
> + spin_lock(&clp->cl_cs_lock);
> + if (test_bit(NFSD4_DESTROY_COURTESY_CLIENT,
> + &clp->cl_flags)) {
> + spin_unlock(&clp->cl_cs_lock);
> + continue;
> + }
> + if (test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags)) {
> + if (!courtesy_clnt) {
> + set_bit(NFSD4_DESTROY_COURTESY_CLIENT,
> + &clp->cl_flags);
> + spin_unlock(&clp->cl_cs_lock);
> + continue;
> + }
> + clear_bit(NFSD4_COURTESY_CLIENT,
> + &clp->cl_flags);
> + *courtesy_clnt = true;
> + }
> + spin_unlock(&clp->cl_cs_lock);
> renew_client_locked(clp);
> return clp;
> }
> @@ -2869,12 +2947,13 @@ find_client_in_id_table(struct list_head *tbl, clientid_t *clid, bool sessions)
> }
>
> static struct nfs4_client *
> -find_confirmed_client(clientid_t *clid, bool sessions, struct nfsd_net *nn)
> +find_confirmed_client(clientid_t *clid, bool sessions, struct nfsd_net *nn,
> + bool *courtesy_clnt)
> {
> struct list_head *tbl = nn->conf_id_hashtbl;
>
> lockdep_assert_held(&nn->client_lock);
> - return find_client_in_id_table(tbl, clid, sessions);
> + return find_client_in_id_table(tbl, clid, sessions, courtesy_clnt);
> }
>
> static struct nfs4_client *
> @@ -2883,7 +2962,7 @@ find_unconfirmed_client(clientid_t *clid, bool sessions, struct nfsd_net *nn)
> struct list_head *tbl = nn->unconf_id_hashtbl;
>
> lockdep_assert_held(&nn->client_lock);
> - return find_client_in_id_table(tbl, clid, sessions);
> + return find_client_in_id_table(tbl, clid, sessions, NULL);
> }
>
> static bool clp_used_exchangeid(struct nfs4_client *clp)
> @@ -2892,17 +2971,18 @@ static bool clp_used_exchangeid(struct nfs4_client *clp)
> }
>
> static struct nfs4_client *
> -find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
> +find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn,
> + bool *courtesy_clnt)
> {
> lockdep_assert_held(&nn->client_lock);
> - return find_clp_in_name_tree(name, &nn->conf_name_tree);
> + return find_clp_in_name_tree(name, &nn->conf_name_tree, courtesy_clnt);
> }
>
> static struct nfs4_client *
> find_unconfirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
> {
> lockdep_assert_held(&nn->client_lock);
> - return find_clp_in_name_tree(name, &nn->unconf_name_tree);
> + return find_clp_in_name_tree(name, &nn->unconf_name_tree, NULL);
> }
>
> static void
> @@ -3176,7 +3256,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>
> /* Cases below refer to rfc 5661 section 18.35.4: */
> spin_lock(&nn->client_lock);
> - conf = find_confirmed_client_by_name(&exid->clname, nn);
> + conf = find_confirmed_client_by_name(&exid->clname, nn, NULL);
> if (conf) {
> bool creds_match = same_creds(&conf->cl_cred, &rqstp->rq_cred);
> bool verfs_match = same_verf(&verf, &conf->cl_verifier);
> @@ -3443,7 +3523,7 @@ nfsd4_create_session(struct svc_rqst *rqstp,
>
> spin_lock(&nn->client_lock);
> unconf = find_unconfirmed_client(&cr_ses->clientid, true, nn);
> - conf = find_confirmed_client(&cr_ses->clientid, true, nn);
> + conf = find_confirmed_client(&cr_ses->clientid, true, nn, NULL);
> WARN_ON_ONCE(conf && unconf);
>
> if (conf) {
> @@ -3474,7 +3554,7 @@ nfsd4_create_session(struct svc_rqst *rqstp,
> status = nfserr_seq_misordered;
> goto out_free_conn;
> }
> - old = find_confirmed_client_by_name(&unconf->cl_name, nn);
> + old = find_confirmed_client_by_name(&unconf->cl_name, nn, NULL);
> if (old) {
> status = mark_client_expired_locked(old);
> if (status) {
> @@ -3613,11 +3693,13 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
> struct nfsd4_session *session;
> struct net *net = SVC_NET(rqstp);
> struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> + bool courtesy_clnt;
>
> if (!nfsd4_last_compound_op(rqstp))
> return nfserr_not_only_op;
> spin_lock(&nn->client_lock);
> - session = find_in_sessionid_hashtbl(&bcts->sessionid, net, &status);
> + session = find_in_sessionid_hashtbl(&bcts->sessionid, net, &status,
> + &courtesy_clnt);
> spin_unlock(&nn->client_lock);
> if (!session)
> goto out_no_session;
> @@ -3647,6 +3729,8 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
> out:
> nfsd4_put_session(session);
> out_no_session:
> + if (status == nfs_ok && courtesy_clnt)
> + nfsd4_client_record_create(session->se_client);
> return status;
> }
>
> @@ -3676,7 +3760,7 @@ nfsd4_destroy_session(struct svc_rqst *r, struct nfsd4_compound_state *cstate,
> }
> dump_sessionid(__func__, sessionid);
> spin_lock(&nn->client_lock);
> - ses = find_in_sessionid_hashtbl(sessionid, net, &status);
> + ses = find_in_sessionid_hashtbl(sessionid, net, &status, NULL);
> if (!ses)
> goto out_client_lock;
> status = nfserr_wrong_cred;
> @@ -3790,6 +3874,7 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> int buflen;
> struct net *net = SVC_NET(rqstp);
> struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> + bool courtesy_clnt;
>
> if (resp->opcnt != 1)
> return nfserr_sequence_pos;
> @@ -3803,7 +3888,8 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> return nfserr_jukebox;
>
> spin_lock(&nn->client_lock);
> - session = find_in_sessionid_hashtbl(&seq->sessionid, net, &status);
> + session = find_in_sessionid_hashtbl(&seq->sessionid, net, &status,
> + &courtesy_clnt);
> if (!session)
> goto out_no_session;
> clp = session->se_client;
> @@ -3893,6 +3979,8 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> if (conn)
> free_conn(conn);
> spin_unlock(&nn->client_lock);
> + if (status == nfs_ok && courtesy_clnt)
> + nfsd4_client_record_create(clp);
> return status;
> out_put_session:
> nfsd4_put_session_locked(session);
> @@ -3928,7 +4016,7 @@ nfsd4_destroy_clientid(struct svc_rqst *rqstp,
>
> spin_lock(&nn->client_lock);
> unconf = find_unconfirmed_client(&dc->clientid, true, nn);
> - conf = find_confirmed_client(&dc->clientid, true, nn);
> + conf = find_confirmed_client(&dc->clientid, true, nn, NULL);
> WARN_ON_ONCE(conf && unconf);
>
> if (conf) {
> @@ -4012,12 +4100,18 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> struct nfs4_client *unconf = NULL;
> __be32 status;
> struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
> + bool courtesy_clnt = false;
> + struct nfs4_client *cclient = NULL;
>
> new = create_client(clname, rqstp, &clverifier);
> if (new == NULL)
> return nfserr_jukebox;
> spin_lock(&nn->client_lock);
> - conf = find_confirmed_client_by_name(&clname, nn);
> + conf = find_confirmed_client_by_name(&clname, nn, &courtesy_clnt);
> + if (conf && courtesy_clnt) {
> + cclient = conf;
> + conf = NULL;
> + }
> if (conf && client_has_state(conf)) {
> status = nfserr_clid_inuse;
> if (clp_used_exchangeid(conf))
> @@ -4048,7 +4142,11 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> new = NULL;
> status = nfs_ok;
> out:
> + if (cclient)
> + unhash_client_locked(cclient);
> spin_unlock(&nn->client_lock);
> + if (cclient)
> + expire_client(cclient);
> if (new)
> free_client(new);
> if (unconf) {
> @@ -4076,8 +4174,9 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
> return nfserr_stale_clientid;
>
> spin_lock(&nn->client_lock);
> - conf = find_confirmed_client(clid, false, nn);
> + conf = find_confirmed_client(clid, false, nn, NULL);
> unconf = find_unconfirmed_client(clid, false, nn);
> +
> /*
> * We try hard to give out unique clientid's, so if we get an
> * attempt to confirm the same clientid with a different cred,
> @@ -4107,7 +4206,7 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
> unhash_client_locked(old);
> nfsd4_change_callback(conf, &unconf->cl_cb_conn);
> } else {
> - old = find_confirmed_client_by_name(&unconf->cl_name, nn);
> + old = find_confirmed_client_by_name(&unconf->cl_name, nn, NULL);
> if (old) {
> status = nfserr_clid_inuse;
> if (client_has_state(old)
> @@ -4691,18 +4790,41 @@ nfsd_break_deleg_cb(struct file_lock *fl)
> return ret;
> }
>
> +/*
> + * Function returns true if lease conflict was resolved
> + * else returns false.
> + */
> static bool nfsd_breaker_owns_lease(struct file_lock *fl)
> {
> struct nfs4_delegation *dl = fl->fl_owner;
> struct svc_rqst *rqst;
> struct nfs4_client *clp;
>
> + clp = dl->dl_stid.sc_client;
> +
> + /*
> + * need to sync with courtesy client trying to reconnect using
> + * the cl_cs_lock, nn->client_lock can not be used since this
> + * function is called with the fl_lck held.
> + */
> + spin_lock(&clp->cl_cs_lock);
> + if (test_bit(NFSD4_DESTROY_COURTESY_CLIENT, &clp->cl_flags)) {
> + spin_unlock(&clp->cl_cs_lock);
> + return true;
> + }
> + if (test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags)) {
> + set_bit(NFSD4_DESTROY_COURTESY_CLIENT, &clp->cl_flags);
> + spin_unlock(&clp->cl_cs_lock);
> + return true;
> + }
> + spin_unlock(&clp->cl_cs_lock);
> +
> if (!i_am_nfsd())
> - return NULL;
> + return false;
> rqst = kthread_data(current);
> /* Note rq_prog == NFS_ACL_PROGRAM is also possible: */
> if (rqst->rq_prog != NFS_PROGRAM || rqst->rq_vers < 4)
> - return NULL;
> + return false;
> clp = *(rqst->rq_lease_breaker);
> return dl->dl_stid.sc_client == clp;
> }
> @@ -4735,12 +4857,12 @@ static __be32 nfsd4_check_seqid(struct nfsd4_compound_state *cstate, struct nfs4
> }
>
> static struct nfs4_client *lookup_clientid(clientid_t *clid, bool sessions,
> - struct nfsd_net *nn)
> + struct nfsd_net *nn, bool *courtesy_clnt)
> {
> struct nfs4_client *found;
>
> spin_lock(&nn->client_lock);
> - found = find_confirmed_client(clid, sessions, nn);
> + found = find_confirmed_client(clid, sessions, nn, courtesy_clnt);
> if (found)
> atomic_inc(&found->cl_rpc_users);
> spin_unlock(&nn->client_lock);
> @@ -4751,6 +4873,8 @@ static __be32 set_client(clientid_t *clid,
> struct nfsd4_compound_state *cstate,
> struct nfsd_net *nn)
> {
> + bool courtesy_clnt;
> +
> if (cstate->clp) {
> if (!same_clid(&cstate->clp->cl_clientid, clid))
> return nfserr_stale_clientid;
> @@ -4762,9 +4886,12 @@ static __be32 set_client(clientid_t *clid,
> * We're in the 4.0 case (otherwise the SEQUENCE op would have
> * set cstate->clp), so session = false:
> */
> - cstate->clp = lookup_clientid(clid, false, nn);
> + cstate->clp = lookup_clientid(clid, false, nn, &courtesy_clnt);
> if (!cstate->clp)
> return nfserr_expired;
> +
> + if (courtesy_clnt)
> + nfsd4_client_record_create(cstate->clp);
> return nfs_ok;
> }
>
> @@ -4917,9 +5044,89 @@ nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh,
> return nfsd_setattr(rqstp, fh, &iattr, 0, (time64_t)0);
> }
>
> -static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
> +static bool
> +nfs4_check_access_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;
> +}
> +
> +/*
> + * This function is called to check whether nfserr_share_denied should
> + * be returning to client.
> + *
> + * access: is op_share_access if share_access is true.
> + * Check if access mode, op_share_access, would conflict with
> + * the current deny mode of the file 'fp'.
> + * access: is op_share_deny if share_access is false.
> + * Check if the deny mode, op_share_deny, would conflict with
> + * current access of the file 'fp'.
> + * stp: skip checking this entry.
> + * new_stp: normal open, not open upgrade.
> + *
> + * Function returns:
> + * true - access/deny mode conflict with normal client.
> + * false - no conflict or conflict with courtesy client(s) is resolved.
> + */
> +static bool
> +nfs4_conflict_clients(struct nfs4_file *fp, bool new_stp,
> + struct nfs4_ol_stateid *stp, u32 access, bool share_access)
> +{
> + struct nfs4_ol_stateid *st;
> + struct nfs4_client *cl;
> + bool conflict = false;
> +
> + lockdep_assert_held(&fp->fi_lock);
> + list_for_each_entry(st, &fp->fi_stateids, st_perfile) {
> + if (st->st_openstp || (st == stp && new_stp) ||
> + (!nfs4_check_access_deny_bmap(st,
> + access, share_access)))
> + continue;
> +
> + /* need to sync with courtesy client trying to reconnect */
> + cl = st->st_stid.sc_client;
> + spin_lock(&cl->cl_cs_lock);
> + if (test_bit(NFSD4_DESTROY_COURTESY_CLIENT, &cl->cl_flags)) {
> + spin_unlock(&cl->cl_cs_lock);
> + continue;
> + }
> + if (test_bit(NFSD4_COURTESY_CLIENT, &cl->cl_flags)) {
> + set_bit(NFSD4_DESTROY_COURTESY_CLIENT, &cl->cl_flags);
> + spin_unlock(&cl->cl_cs_lock);
> + continue;
> + }
> + /* conflict not caused by courtesy client */
> + spin_unlock(&cl->cl_cs_lock);
> + conflict = true;
> + break;
> + }
> + return conflict;
> +}
> +
> +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)
> + struct nfsd4_open *open, bool new_stp)
> {
> struct nfsd_file *nf = NULL;
> __be32 status;
> @@ -4935,15 +5142,29 @@ 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);
> - goto out;
> + if (status != nfserr_share_denied) {
> + spin_unlock(&fp->fi_lock);
> + goto out;
> + }
> + if (nfs4_conflict_clients(fp, new_stp, stp,
> + open->op_share_deny, false)) {
> + spin_unlock(&fp->fi_lock);
> + goto out;
> + }
> }
>
> /* set access to the file */
> status = nfs4_file_get_access(fp, open->op_share_access);
> if (status != nfs_ok) {
> - spin_unlock(&fp->fi_lock);
> - goto out;
> + if (status != nfserr_share_denied) {
> + spin_unlock(&fp->fi_lock);
> + goto out;
> + }
> + if (nfs4_conflict_clients(fp, new_stp, stp,
> + open->op_share_access, true)) {
> + spin_unlock(&fp->fi_lock);
> + goto out;
> + }
> }
>
> /* Set access bits in stateid */
> @@ -4994,7 +5215,7 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp, struct svc_fh *c
> unsigned char old_deny_bmap = stp->st_deny_bmap;
>
> if (!test_access(open->op_share_access, stp))
> - return nfs4_get_vfs_file(rqstp, fp, cur_fh, stp, open);
> + return nfs4_get_vfs_file(rqstp, fp, cur_fh, stp, open, false);
>
> /* test and set deny mode */
> spin_lock(&fp->fi_lock);
> @@ -5343,7 +5564,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
> goto out;
> }
> } else {
> - status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open);
> + status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open, true);
> if (status) {
> stp->st_stid.sc_type = NFS4_CLOSED_STID;
> release_open_stateid(stp);
> @@ -5577,6 +5798,122 @@ static void nfsd4_ssc_expire_umount(struct nfsd_net *nn)
> }
> #endif
>
> +static bool
> +nfs4_anylock_blocker(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;
> +
> + spin_lock(&clp->cl_lock);
> + 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)) {
> + spin_unlock(&clp->cl_lock);
> + return true;
> + }
> + }
> + }
> + }
> + }
> + spin_unlock(&clp->cl_lock);
> + 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;
> + bool cour;
> + struct list_head cslist;
> +
> + INIT_LIST_HEAD(reaplist);
> + INIT_LIST_HEAD(&cslist);
> + 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(lt, clp->cl_time))
> + break;
> +
> + /* client expired */
> + if (!client_has_state(clp)) {
> + if (mark_client_expired_locked(clp))
> + continue;
> + list_add(&clp->cl_lru, reaplist);
> + continue;
> + }
> +
> + /* expired client has state */
> + if (test_bit(NFSD4_DESTROY_COURTESY_CLIENT, &clp->cl_flags))
> + goto exp_client;
> +
> + cour = test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags);
> + if (cour &&
> + ktime_get_boottime_seconds() >= clp->courtesy_client_expiry)
> + goto exp_client;
> +
> + if (nfs4_anylock_blocker(clp)) {
> + /* expired client has state and has blocker. */
> +exp_client:
> + if (mark_client_expired_locked(clp))
> + continue;
> + list_add(&clp->cl_lru, reaplist);
> + continue;
> + }
> + /*
> + * Client expired and has state and has no blockers.
> + * If there is race condition with blockers, next time
> + * the laundromat runs it will catch it and expires
> + * the client. Client is expected to retry on lock or
> + * lease conflict.
> + */
> + if (!cour) {
> + set_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags);
> + clp->courtesy_client_expiry = ktime_get_boottime_seconds() +
> + courtesy_client_expiry;
> + list_add(&clp->cl_cs_list, &cslist);
> + }
> + }
> + spin_unlock(&nn->client_lock);
> +
> + list_for_each_entry(clp, &cslist, cl_cs_list) {
> + spin_lock(&clp->cl_cs_lock);
> + if (test_bit(NFSD4_DESTROY_COURTESY_CLIENT, &clp->cl_flags) ||
> + !test_bit(NFSD4_COURTESY_CLIENT,
> + &clp->cl_flags)) {
> + spin_unlock(&clp->cl_cs_lock);
> + continue;
> + }
> + spin_unlock(&clp->cl_cs_lock);
> + nfsd4_client_record_remove(clp);
> + }
> +}
> +
> static time64_t
> nfs4_laundromat(struct nfsd_net *nn)
> {
> @@ -5610,16 +5947,7 @@ nfs4_laundromat(struct nfsd_net *nn)
> }
> 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);
> @@ -5998,7 +6326,7 @@ static __be32 find_cpntf_state(struct nfsd_net *nn, stateid_t *st,
> cps->cpntf_time = ktime_get_boottime_seconds();
>
> status = nfserr_expired;
> - found = lookup_clientid(&cps->cp_p_clid, true, nn);
> + found = lookup_clientid(&cps->cp_p_clid, true, nn, NULL);
> if (!found)
> goto out;
>
> @@ -6501,6 +6829,43 @@ nfs4_transform_lock_offset(struct file_lock *lock)
> lock->fl_end = OFFSET_MAX;
> }
>
> +/**
> + * nfsd4_fl_lock_conflict - check if lock conflict can be resolved.
> + *
> + * @fl: pointer to file_lock with a potential conflict
> + * Return values:
> + * %true: real conflict, lock conflict can not be resolved.
> + * %false: no conflict, lock conflict was resolved.
> + *
> + * Note that this function is called while the flc_lock is held.
> + */
> +static bool
> +nfsd4_fl_lock_conflict(struct file_lock *fl)
> +{
> + struct nfs4_lockowner *lo;
> + struct nfs4_client *clp;
> + bool rc = true;
> +
> + if (!fl)
> + return true;
> + lo = (struct nfs4_lockowner *)fl->fl_owner;
> + clp = lo->lo_owner.so_client;
> +
> + /* need to sync with courtesy client trying to reconnect */
> + spin_lock(&clp->cl_cs_lock);
> + if (test_bit(NFSD4_DESTROY_COURTESY_CLIENT, &clp->cl_flags))
> + rc = false;
> + else {
> + if (test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags)) {
> + set_bit(NFSD4_DESTROY_COURTESY_CLIENT, &clp->cl_flags);
> + rc = false;
> + } else
> + rc = true;
> + }
> + spin_unlock(&clp->cl_cs_lock);
> + return rc;
> +}
> +
> static fl_owner_t
> nfsd4_fl_get_owner(fl_owner_t owner)
> {
> @@ -6548,6 +6913,7 @@ 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_lock_conflict = nfsd4_fl_lock_conflict,
> };
>
> static inline void
> diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
> index e73bdbb1634a..b75f4c70706d 100644
> --- a/fs/nfsd/state.h
> +++ b/fs/nfsd/state.h
> @@ -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 +387,9 @@ 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 */
> + int courtesy_client_expiry;
> + spinlock_t cl_cs_lock;
> + struct list_head cl_cs_list;
> };
>
> /* struct nfs4_client_reset
> --
> 2.9.5
>
--
Chuck Lever
