Thanks for your persistence, this is a tricky project!:
On Wed, Feb 09, 2022 at 08:52:09PM -0800, Dai Ngo 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.
CLients have a lot of leeway there, and that's a detail not important to
this patch. Just cut this sentence.
> 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.
This patch is heavy reading. Let's not make it longer than necessary.
I'd replace the above paragraphs by something short like:
Problems such as hardware failures or administrative errors may
cause network partitions longer than the NFSv4 lease period.
Our server currently removes all client state as soon as a
client fails to renew.
> 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 NFSD4_CLIENT_COURTESY and skips destroying the client and
> all of its 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 NFSD4_CLIENT_DESTROY_COURTESY,
> effectively disable it, then allow the current request to proceed
> immediately.
>
> . Courtesy client marked as NFSD4_CLIENT_DESTROY_COURTESY is not allowed to
> reconnect to reuse itsstate. It is expired by the laundromat asynchronously
> in the background.
I haven't had a chance to read the code in detail yet. Two things do
jump out at me:
- Why the two flags? (CLIENT_COURTESY and CLIENT_COURTESY_CLNT?)
Are you sure that's necessary? If so, that could use some
documentation.
- There is a lot of duplicated code. For example, the code
added to find_in_sessionid_hashtable, find_clp_in_name_tree,
and find_client_in_id_table. Any place you find yourself
repeating more than a line or two of code, please consider
factoring it out into a separate function. That would make
this easier to read.
--b.
>
> Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
> ---
> fs/nfsd/nfs4state.c | 446 +++++++++++++++++++++++++++++++++++++++++++++++++---
> fs/nfsd/nfsd.h | 1 +
> fs/nfsd/state.h | 6 +
> 3 files changed, 430 insertions(+), 23 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 1956d377d1a6..a50a670e2088 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1917,10 +1917,27 @@ find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net,
> {
> 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 (clp) {
> + clear_bit(NFSD4_CLIENT_COURTESY_CLNT, &clp->cl_flags);
> + /* need to sync with thread resolving lock/deleg conflict */
> + spin_lock(&clp->cl_cs_lock);
> + if (test_bit(NFSD4_CLIENT_DESTROY_COURTESY, &clp->cl_flags)) {
> + spin_unlock(&clp->cl_cs_lock);
> + session = NULL;
> + goto out;
> + }
> + if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
> + clear_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags);
> + set_bit(NFSD4_CLIENT_COURTESY_CLNT, &clp->cl_flags);
> + }
> + spin_unlock(&clp->cl_cs_lock);
> + }
> status = nfsd4_get_session_locked(session);
> if (status)
> session = NULL;
> @@ -1990,6 +2007,7 @@ 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 +2015,7 @@ 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 +2413,10 @@ 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_CLIENT_COURTESY, &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);
> @@ -2814,8 +2837,22 @@ 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 {
> + clear_bit(NFSD4_CLIENT_COURTESY_CLNT, &clp->cl_flags);
> + /* sync with thread resolving lock/deleg conflict */
> + spin_lock(&clp->cl_cs_lock);
> + if (test_bit(NFSD4_CLIENT_DESTROY_COURTESY,
> + &clp->cl_flags)) {
> + spin_unlock(&clp->cl_cs_lock);
> + return NULL;
> + }
> + if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
> + clear_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags);
> + set_bit(NFSD4_CLIENT_COURTESY_CLNT, &clp->cl_flags);
> + }
> + spin_unlock(&clp->cl_cs_lock);
> return clp;
> + }
> }
> return NULL;
> }
> @@ -2861,6 +2898,20 @@ find_client_in_id_table(struct list_head *tbl, clientid_t *clid, bool sessions)
> if (same_clid(&clp->cl_clientid, clid)) {
> if ((bool)clp->cl_minorversion != sessions)
> return NULL;
> +
> + /* need to sync with thread resolving lock/deleg conflict */
> + clear_bit(NFSD4_CLIENT_COURTESY_CLNT, &clp->cl_flags);
> + spin_lock(&clp->cl_cs_lock);
> + if (test_bit(NFSD4_CLIENT_DESTROY_COURTESY,
> + &clp->cl_flags)) {
> + spin_unlock(&clp->cl_cs_lock);
> + continue;
> + }
> + if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
> + clear_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags);
> + set_bit(NFSD4_CLIENT_COURTESY_CLNT, &clp->cl_flags);
> + }
> + spin_unlock(&clp->cl_cs_lock);
> renew_client_locked(clp);
> return clp;
> }
> @@ -3177,6 +3228,12 @@ 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);
> + if (conf && test_bit(NFSD4_CLIENT_COURTESY_CLNT, &conf->cl_flags)) {
> + spin_lock(&conf->cl_cs_lock);
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &conf->cl_flags);
> + spin_unlock(&conf->cl_cs_lock);
> + conf = NULL;
> + }
> if (conf) {
> bool creds_match = same_creds(&conf->cl_cred, &rqstp->rq_cred);
> bool verfs_match = same_verf(&verf, &conf->cl_verifier);
> @@ -3444,6 +3501,12 @@ 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);
> + if (conf && test_bit(NFSD4_CLIENT_COURTESY_CLNT, &conf->cl_flags)) {
> + spin_lock(&conf->cl_cs_lock);
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &conf->cl_flags);
> + spin_unlock(&conf->cl_cs_lock);
> + conf = NULL;
> + }
> WARN_ON_ONCE(conf && unconf);
>
> if (conf) {
> @@ -3475,6 +3538,12 @@ nfsd4_create_session(struct svc_rqst *rqstp,
> goto out_free_conn;
> }
> old = find_confirmed_client_by_name(&unconf->cl_name, nn);
> + if (old && test_bit(NFSD4_CLIENT_COURTESY_CLNT, &old->cl_flags)) {
> + spin_lock(&old->cl_cs_lock);
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &old->cl_flags);
> + spin_unlock(&old->cl_cs_lock);
> + old = NULL;
> + }
> if (old) {
> status = mark_client_expired_locked(old);
> if (status) {
> @@ -3613,6 +3682,7 @@ __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);
> + struct nfs4_client *clp;
>
> if (!nfsd4_last_compound_op(rqstp))
> return nfserr_not_only_op;
> @@ -3645,6 +3715,16 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
> nfsd4_init_conn(rqstp, conn, session);
> status = nfs_ok;
> out:
> + clp = session->se_client;
> + if (test_bit(NFSD4_CLIENT_COURTESY_CLNT, &clp->cl_flags)) {
> + if (status == nfs_ok)
> + nfsd4_client_record_create(clp);
> + else {
> + spin_lock(&clp->cl_cs_lock);
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &clp->cl_flags);
> + spin_unlock(&clp->cl_cs_lock);
> + }
> + }
> nfsd4_put_session(session);
> out_no_session:
> return status;
> @@ -3667,6 +3747,7 @@ nfsd4_destroy_session(struct svc_rqst *r, struct nfsd4_compound_state *cstate,
> int ref_held_by_me = 0;
> struct net *net = SVC_NET(r);
> struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> + struct nfs4_client *clp;
>
> status = nfserr_not_only_op;
> if (nfsd4_compound_in_session(cstate, sessionid)) {
> @@ -3679,6 +3760,15 @@ nfsd4_destroy_session(struct svc_rqst *r, struct nfsd4_compound_state *cstate,
> ses = find_in_sessionid_hashtbl(sessionid, net, &status);
> if (!ses)
> goto out_client_lock;
> + clp = ses->se_client;
> + if (test_bit(NFSD4_CLIENT_COURTESY_CLNT, &clp->cl_flags)) {
> + status = nfserr_badsession;
> + spin_lock(&clp->cl_cs_lock);
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &clp->cl_flags);
> + spin_unlock(&clp->cl_cs_lock);
> + goto out_put_session;
> + }
> +
> status = nfserr_wrong_cred;
> if (!nfsd4_mach_creds_match(ses->se_client, r))
> goto out_put_session;
> @@ -3783,7 +3873,7 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> struct nfsd4_compoundres *resp = rqstp->rq_resp;
> struct xdr_stream *xdr = resp->xdr;
> struct nfsd4_session *session;
> - struct nfs4_client *clp;
> + struct nfs4_client *clp = NULL;
> struct nfsd4_slot *slot;
> struct nfsd4_conn *conn;
> __be32 status;
> @@ -3893,6 +3983,15 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> if (conn)
> free_conn(conn);
> spin_unlock(&nn->client_lock);
> + if (clp && test_bit(NFSD4_CLIENT_COURTESY_CLNT, &clp->cl_flags)) {
> + if (status == nfs_ok)
> + nfsd4_client_record_create(clp);
> + else {
> + spin_lock(&clp->cl_cs_lock);
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &clp->cl_flags);
> + spin_unlock(&clp->cl_cs_lock);
> + }
> + }
> return status;
> out_put_session:
> nfsd4_put_session_locked(session);
> @@ -3929,6 +4028,12 @@ 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);
> + if (conf && test_bit(NFSD4_CLIENT_COURTESY_CLNT, &conf->cl_flags)) {
> + spin_lock(&conf->cl_cs_lock);
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &conf->cl_flags);
> + spin_unlock(&conf->cl_cs_lock);
> + conf = NULL;
> + }
> WARN_ON_ONCE(conf && unconf);
>
> if (conf) {
> @@ -4012,12 +4117,17 @@ 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);
> + 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);
> + if (conf && test_bit(NFSD4_CLIENT_COURTESY_CLNT, &conf->cl_flags)) {
> + cclient = conf;
> + conf = NULL;
> + }
> if (conf && client_has_state(conf)) {
> status = nfserr_clid_inuse;
> if (clp_used_exchangeid(conf))
> @@ -4048,7 +4158,11 @@ 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) {
> @@ -4078,6 +4192,12 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
> spin_lock(&nn->client_lock);
> conf = find_confirmed_client(clid, false, nn);
> unconf = find_unconfirmed_client(clid, false, nn);
> + if (conf && test_bit(NFSD4_CLIENT_COURTESY_CLNT, &conf->cl_flags)) {
> + spin_lock(&conf->cl_cs_lock);
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &conf->cl_flags);
> + spin_unlock(&conf->cl_cs_lock);
> + conf = NULL;
> + }
> /*
> * We try hard to give out unique clientid's, so if we get an
> * attempt to confirm the same clientid with a different cred,
> @@ -4108,6 +4228,13 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
> nfsd4_change_callback(conf, &unconf->cl_cb_conn);
> } else {
> old = find_confirmed_client_by_name(&unconf->cl_name, nn);
> + if (old && test_bit(NFSD4_CLIENT_COURTESY_CLNT,
> + &old->cl_flags)) {
> + spin_lock(&old->cl_cs_lock);
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &old->cl_flags);
> + spin_unlock(&old->cl_cs_lock);
> + old = NULL;
> + }
> if (old) {
> status = nfserr_clid_inuse;
> if (client_has_state(old)
> @@ -4691,18 +4818,41 @@ 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_CLIENT_DESTROY_COURTESY, &clp->cl_flags)) {
> + spin_unlock(&clp->cl_cs_lock);
> + return true;
> + }
> + if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &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;
> }
> @@ -4735,7 +4885,7 @@ 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)
> {
> struct nfs4_client *found;
>
> @@ -4765,6 +4915,9 @@ static __be32 set_client(clientid_t *clid,
> cstate->clp = lookup_clientid(clid, false, nn);
> if (!cstate->clp)
> return nfserr_expired;
> +
> + if (test_bit(NFSD4_CLIENT_COURTESY_CLNT, &cstate->clp->cl_flags))
> + nfsd4_client_record_create(cstate->clp);
> return nfs_ok;
> }
>
> @@ -4917,9 +5070,89 @@ 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_CLIENT_DESTROY_COURTESY, &cl->cl_flags)) {
> + spin_unlock(&cl->cl_cs_lock);
> + continue;
> + }
> + if (test_bit(NFSD4_CLIENT_COURTESY, &cl->cl_flags)) {
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &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 +5168,29 @@ 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 +5241,7 @@ 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 +5590,7 @@ 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 +5824,121 @@ 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_CLIENT_DESTROY_COURTESY, &clp->cl_flags))
> + goto exp_client;
> +
> + cour = test_bit(NFSD4_CLIENT_COURTESY, &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.
> + */
> + if (!cour) {
> + set_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags);
> + clp->courtesy_client_expiry = ktime_get_boottime_seconds() +
> + NFSD_COURTESY_CLIENT_TIMEOUT;
> + 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_CLIENT_DESTROY_COURTESY, &clp->cl_flags) ||
> + !test_bit(NFSD4_CLIENT_COURTESY,
> + &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 +5972,7 @@ 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);
> @@ -6001,6 +6354,15 @@ static __be32 find_cpntf_state(struct nfsd_net *nn, stateid_t *st,
> found = lookup_clientid(&cps->cp_p_clid, true, nn);
> if (!found)
> goto out;
> + if (test_bit(NFSD4_CLIENT_COURTESY_CLNT, &found->cl_flags)) {
> + spin_lock(&found->cl_cs_lock);
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &found->cl_flags);
> + spin_unlock(&found->cl_cs_lock);
> + if (atomic_dec_and_lock(&found->cl_rpc_users,
> + &nn->client_lock))
> + spin_unlock(&nn->client_lock);
> + goto out;
> + }
>
> *stid = find_stateid_by_type(found, &cps->cp_p_stateid,
> NFS4_DELEG_STID|NFS4_OPEN_STID|NFS4_LOCK_STID);
> @@ -6501,6 +6863,43 @@ 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_CLIENT_DESTROY_COURTESY, &clp->cl_flags))
> + rc = false;
> + else {
> + if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
> + set_bit(NFSD4_CLIENT_DESTROY_COURTESY, &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 +6947,7 @@ 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/nfsd.h b/fs/nfsd/nfsd.h
> index 498e5a489826..5e3e699c8e76 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 e73bdbb1634a..c3c65421d422 100644
> --- a/fs/nfsd/state.h
> +++ b/fs/nfsd/state.h
> @@ -345,6 +345,9 @@ 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_CLIENT_COURTESY (6) /* be nice to expired client */
> +#define NFSD4_CLIENT_DESTROY_COURTESY (7)
> +#define NFSD4_CLIENT_COURTESY_CLNT (8)
> unsigned long cl_flags;
> const struct cred *cl_cb_cred;
> struct rpc_clnt *cl_cb_client;
> @@ -385,6 +388,9 @@ 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
