| Message ID | 20240129033637.2133-10-neilb@suse.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | nfsd: support admin-revocation of v4 state | expand |
On Mon, 2024-01-29 at 14:29 +1100, NeilBrown wrote: > For NFSv4.1 and later the client easily discovers if there is any > admin-revoked state and will then find and explicitly free it. > > For NFSv4.0 there is no such mechanism. The client can only find that > state is admin-revoked if it tries to use that state, and there is no > way for it to explicitly free the state. So the server must hold on to > the stateid (at least) for an indefinite amount of time. A > RELEASE_LOCKOWNER request might justify forgetting some of these > stateids, as would the whole clients lease lapsing, but these are not > reliable. > > This patch takes two approaches. > > Whenever a client uses an revoked stateid, that stateid is then > discarded and will not be recognised again. This might confuse a client > which expect to get NFS4ERR_ADMIN_REVOKED consistently once it get it at > all, but should mostly work. Hopefully one error will lead to other > resources being closed (e.g. process exits), which will result in more > stateid being freed when a CLOSE attempt gets NFS4ERR_ADMIN_REVOKED. > > Also, any admin-revoked stateids that have been that way for more than > one lease time are periodically revoke. > > No actual freeing of state happens in this patch. That will come in > future patches which handle the different sorts of revoked state. > > Signed-off-by: NeilBrown <neilb@suse.de> > --- > fs/nfsd/netns.h | 4 ++ > fs/nfsd/nfs4state.c | 98 ++++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 101 insertions(+), 1 deletion(-) > > diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h > index 74b4360779a1..b35bdd5c10de 100644 > --- a/fs/nfsd/netns.h > +++ b/fs/nfsd/netns.h > @@ -192,6 +192,10 @@ struct nfsd_net { > atomic_t nfsd_courtesy_clients; > struct shrinker *nfsd_client_shrinker; > struct work_struct nfsd_shrinker_work; > + > + /* last time an admin-revoke happened for NFSv4.0 */ > + time64_t nfs40_last_revoke; > + > }; > > /* Simple check to find out if a given net was properly initialized */ > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index e1492ca7c75c..900d295bd570 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -1733,6 +1733,14 @@ void nfsd4_revoke_states(struct net *net, struct super_block *sb) > } > nfs4_put_stid(stid); > spin_lock(&nn->client_lock); > + if (clp->cl_minorversion == 0) > + /* Allow cleanup after a lease period. > + * store_release ensures cleanup will > + * see any newly revoked states if it > + * sees the time updated. > + */ > + nn->nfs40_last_revoke = > + ktime_get_boottime_seconds(); > goto retry; > } > } > @@ -4617,6 +4625,40 @@ nfsd4_find_existing_open(struct nfs4_file *fp, struct nfsd4_open *open) > return ret; > } > > +static void nfsd4_drop_revoked_stid(struct nfs4_stid *s) > + __releases(&s->sc_client->cl_lock) > +{ > + struct nfs4_client *cl = s->sc_client; > + > + switch (s->sc_type) { > + default: > + spin_unlock(&cl->cl_lock); > + } > +} > + > +static void nfsd40_drop_revoked_stid(struct nfs4_client *cl, > + stateid_t *stid) > +{ > + /* NFSv4.0 has no way for the client to tell the server > + * that it can forget an admin-revoked stateid. > + * So we keep it around until the first time that the > + * client uses it, and drop it the first time > + * nfserr_admin_revoked is returned. > + * For v4.1 and later we wait until explicitly told > + * to free the stateid. > + */ > + if (cl->cl_minorversion == 0) { > + struct nfs4_stid *st; > + > + spin_lock(&cl->cl_lock); > + st = find_stateid_locked(cl, stid); > + if (st) > + nfsd4_drop_revoked_stid(st); > + else > + spin_unlock(&cl->cl_lock); > + } > +} > + > static __be32 > nfsd4_verify_open_stid(struct nfs4_stid *s) > { > @@ -4639,6 +4681,10 @@ nfsd4_lock_ol_stateid(struct nfs4_ol_stateid *stp) > > mutex_lock_nested(&stp->st_mutex, LOCK_STATEID_MUTEX); > ret = nfsd4_verify_open_stid(&stp->st_stid); > + if (ret == nfserr_admin_revoked) > + nfsd40_drop_revoked_stid(stp->st_stid.sc_client, > + &stp->st_stid.sc_stateid); > + > if (ret != nfs_ok) > mutex_unlock(&stp->st_mutex); > return ret; > @@ -5222,6 +5268,7 @@ nfs4_check_deleg(struct nfs4_client *cl, struct nfsd4_open *open, > } > if (deleg->dl_stid.sc_status & SC_STATUS_REVOKED) { > nfs4_put_stid(&deleg->dl_stid); > + nfsd40_drop_revoked_stid(cl, &open->op_delegate_stateid); > status = nfserr_deleg_revoked; > goto out; > } > @@ -6206,6 +6253,43 @@ nfs4_process_client_reaplist(struct list_head *reaplist) > } > } > > +static void nfs40_clean_admin_revoked(struct nfsd_net *nn, > + struct laundry_time *lt) > +{ > + struct nfs4_client *clp; > + > + spin_lock(&nn->client_lock); > + if (nn->nfs40_last_revoke == 0 || > + nn->nfs40_last_revoke > lt->cutoff) { > + spin_unlock(&nn->client_lock); > + return; > + } > + nn->nfs40_last_revoke = 0; > + > +retry: > + list_for_each_entry(clp, &nn->client_lru, cl_lru) { > + unsigned long id, tmp; > + struct nfs4_stid *stid; > + > + if (atomic_read(&clp->cl_admin_revoked) == 0) > + continue; > + > + spin_lock(&clp->cl_lock); > + idr_for_each_entry_ul(&clp->cl_stateids, stid, tmp, id) > + if (stid->sc_status & SC_STATUS_ADMIN_REVOKED) { > + refcount_inc(&stid->sc_count); > + spin_unlock(&nn->client_lock); > + /* this function drops ->cl_lock */ > + nfsd4_drop_revoked_stid(stid); > + nfs4_put_stid(stid); > + spin_lock(&nn->client_lock); > + goto retry; > + } > + spin_unlock(&clp->cl_lock); > + } > + spin_unlock(&nn->client_lock); > +} > + > static time64_t > nfs4_laundromat(struct nfsd_net *nn) > { > @@ -6239,6 +6323,8 @@ nfs4_laundromat(struct nfsd_net *nn) > nfs4_get_client_reaplist(nn, &reaplist, <); > nfs4_process_client_reaplist(&reaplist); > > + nfs40_clean_admin_revoked(nn, <); > + > spin_lock(&state_lock); > list_for_each_safe(pos, next, &nn->del_recall_lru) { > dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru); > @@ -6457,6 +6543,9 @@ static __be32 nfsd4_stid_check_stateid_generation(stateid_t *in, struct nfs4_sti > if (ret == nfs_ok) > ret = check_stateid_generation(in, &s->sc_stateid, has_session); > spin_unlock(&s->sc_lock); > + if (ret == nfserr_admin_revoked) > + nfsd40_drop_revoked_stid(s->sc_client, > + &s->sc_stateid); > return ret; > } > > @@ -6501,6 +6590,8 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid) > } > out_unlock: > spin_unlock(&cl->cl_lock); > + if (status == nfserr_admin_revoked) > + nfsd40_drop_revoked_stid(cl, stateid); > return status; > } > > @@ -6547,6 +6638,7 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate, > return nfserr_deleg_revoked; > } > if (stid->sc_status & SC_STATUS_ADMIN_REVOKED) { > + nfsd40_drop_revoked_stid(cstate->clp, stateid); > nfs4_put_stid(stid); > return nfserr_admin_revoked; > } > @@ -6839,6 +6931,11 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, > s = find_stateid_locked(cl, stateid); > if (!s || s->sc_status & SC_STATUS_CLOSED) > goto out_unlock; > + if (s->sc_status & SC_STATUS_ADMIN_REVOKED) { > + nfsd4_drop_revoked_stid(s); > + ret = nfs_ok; > + goto out; > + } > spin_lock(&s->sc_lock); > switch (s->sc_type) { > case SC_TYPE_DELEG: > @@ -6865,7 +6962,6 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, > spin_unlock(&cl->cl_lock); > ret = nfsd4_free_lock_stateid(stateid, s); > goto out; > - /* Default falls through and returns nfserr_bad_stateid */ > } > spin_unlock(&s->sc_lock); > out_unlock: Reviewed-by: Jeff Layton <jlayton@kernel.org>
diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h index 74b4360779a1..b35bdd5c10de 100644 --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -192,6 +192,10 @@ struct nfsd_net { atomic_t nfsd_courtesy_clients; struct shrinker *nfsd_client_shrinker; struct work_struct nfsd_shrinker_work; + + /* last time an admin-revoke happened for NFSv4.0 */ + time64_t nfs40_last_revoke; + }; /* Simple check to find out if a given net was properly initialized */ diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index e1492ca7c75c..900d295bd570 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1733,6 +1733,14 @@ void nfsd4_revoke_states(struct net *net, struct super_block *sb) } nfs4_put_stid(stid); spin_lock(&nn->client_lock); + if (clp->cl_minorversion == 0) + /* Allow cleanup after a lease period. + * store_release ensures cleanup will + * see any newly revoked states if it + * sees the time updated. + */ + nn->nfs40_last_revoke = + ktime_get_boottime_seconds(); goto retry; } } @@ -4617,6 +4625,40 @@ nfsd4_find_existing_open(struct nfs4_file *fp, struct nfsd4_open *open) return ret; } +static void nfsd4_drop_revoked_stid(struct nfs4_stid *s) + __releases(&s->sc_client->cl_lock) +{ + struct nfs4_client *cl = s->sc_client; + + switch (s->sc_type) { + default: + spin_unlock(&cl->cl_lock); + } +} + +static void nfsd40_drop_revoked_stid(struct nfs4_client *cl, + stateid_t *stid) +{ + /* NFSv4.0 has no way for the client to tell the server + * that it can forget an admin-revoked stateid. + * So we keep it around until the first time that the + * client uses it, and drop it the first time + * nfserr_admin_revoked is returned. + * For v4.1 and later we wait until explicitly told + * to free the stateid. + */ + if (cl->cl_minorversion == 0) { + struct nfs4_stid *st; + + spin_lock(&cl->cl_lock); + st = find_stateid_locked(cl, stid); + if (st) + nfsd4_drop_revoked_stid(st); + else + spin_unlock(&cl->cl_lock); + } +} + static __be32 nfsd4_verify_open_stid(struct nfs4_stid *s) { @@ -4639,6 +4681,10 @@ nfsd4_lock_ol_stateid(struct nfs4_ol_stateid *stp) mutex_lock_nested(&stp->st_mutex, LOCK_STATEID_MUTEX); ret = nfsd4_verify_open_stid(&stp->st_stid); + if (ret == nfserr_admin_revoked) + nfsd40_drop_revoked_stid(stp->st_stid.sc_client, + &stp->st_stid.sc_stateid); + if (ret != nfs_ok) mutex_unlock(&stp->st_mutex); return ret; @@ -5222,6 +5268,7 @@ nfs4_check_deleg(struct nfs4_client *cl, struct nfsd4_open *open, } if (deleg->dl_stid.sc_status & SC_STATUS_REVOKED) { nfs4_put_stid(&deleg->dl_stid); + nfsd40_drop_revoked_stid(cl, &open->op_delegate_stateid); status = nfserr_deleg_revoked; goto out; } @@ -6206,6 +6253,43 @@ nfs4_process_client_reaplist(struct list_head *reaplist) } } +static void nfs40_clean_admin_revoked(struct nfsd_net *nn, + struct laundry_time *lt) +{ + struct nfs4_client *clp; + + spin_lock(&nn->client_lock); + if (nn->nfs40_last_revoke == 0 || + nn->nfs40_last_revoke > lt->cutoff) { + spin_unlock(&nn->client_lock); + return; + } + nn->nfs40_last_revoke = 0; + +retry: + list_for_each_entry(clp, &nn->client_lru, cl_lru) { + unsigned long id, tmp; + struct nfs4_stid *stid; + + if (atomic_read(&clp->cl_admin_revoked) == 0) + continue; + + spin_lock(&clp->cl_lock); + idr_for_each_entry_ul(&clp->cl_stateids, stid, tmp, id) + if (stid->sc_status & SC_STATUS_ADMIN_REVOKED) { + refcount_inc(&stid->sc_count); + spin_unlock(&nn->client_lock); + /* this function drops ->cl_lock */ + nfsd4_drop_revoked_stid(stid); + nfs4_put_stid(stid); + spin_lock(&nn->client_lock); + goto retry; + } + spin_unlock(&clp->cl_lock); + } + spin_unlock(&nn->client_lock); +} + static time64_t nfs4_laundromat(struct nfsd_net *nn) { @@ -6239,6 +6323,8 @@ nfs4_laundromat(struct nfsd_net *nn) nfs4_get_client_reaplist(nn, &reaplist, <); nfs4_process_client_reaplist(&reaplist); + nfs40_clean_admin_revoked(nn, <); + spin_lock(&state_lock); list_for_each_safe(pos, next, &nn->del_recall_lru) { dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru); @@ -6457,6 +6543,9 @@ static __be32 nfsd4_stid_check_stateid_generation(stateid_t *in, struct nfs4_sti if (ret == nfs_ok) ret = check_stateid_generation(in, &s->sc_stateid, has_session); spin_unlock(&s->sc_lock); + if (ret == nfserr_admin_revoked) + nfsd40_drop_revoked_stid(s->sc_client, + &s->sc_stateid); return ret; } @@ -6501,6 +6590,8 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid) } out_unlock: spin_unlock(&cl->cl_lock); + if (status == nfserr_admin_revoked) + nfsd40_drop_revoked_stid(cl, stateid); return status; } @@ -6547,6 +6638,7 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate, return nfserr_deleg_revoked; } if (stid->sc_status & SC_STATUS_ADMIN_REVOKED) { + nfsd40_drop_revoked_stid(cstate->clp, stateid); nfs4_put_stid(stid); return nfserr_admin_revoked; } @@ -6839,6 +6931,11 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, s = find_stateid_locked(cl, stateid); if (!s || s->sc_status & SC_STATUS_CLOSED) goto out_unlock; + if (s->sc_status & SC_STATUS_ADMIN_REVOKED) { + nfsd4_drop_revoked_stid(s); + ret = nfs_ok; + goto out; + } spin_lock(&s->sc_lock); switch (s->sc_type) { case SC_TYPE_DELEG: @@ -6865,7 +6962,6 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, spin_unlock(&cl->cl_lock); ret = nfsd4_free_lock_stateid(stateid, s); goto out; - /* Default falls through and returns nfserr_bad_stateid */ } spin_unlock(&s->sc_lock); out_unlock:
For NFSv4.1 and later the client easily discovers if there is any admin-revoked state and will then find and explicitly free it. For NFSv4.0 there is no such mechanism. The client can only find that state is admin-revoked if it tries to use that state, and there is no way for it to explicitly free the state. So the server must hold on to the stateid (at least) for an indefinite amount of time. A RELEASE_LOCKOWNER request might justify forgetting some of these stateids, as would the whole clients lease lapsing, but these are not reliable. This patch takes two approaches. Whenever a client uses an revoked stateid, that stateid is then discarded and will not be recognised again. This might confuse a client which expect to get NFS4ERR_ADMIN_REVOKED consistently once it get it at all, but should mostly work. Hopefully one error will lead to other resources being closed (e.g. process exits), which will result in more stateid being freed when a CLOSE attempt gets NFS4ERR_ADMIN_REVOKED. Also, any admin-revoked stateids that have been that way for more than one lease time are periodically revoke. No actual freeing of state happens in this patch. That will come in future patches which handle the different sorts of revoked state. Signed-off-by: NeilBrown <neilb@suse.de> --- fs/nfsd/netns.h | 4 ++ fs/nfsd/nfs4state.c | 98 ++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 101 insertions(+), 1 deletion(-)