On Mon, 2024-01-29 at 14:29 +1100, NeilBrown wrote:
> The NFSv4 protocol allows state to be revoked by the admin and has error
> codes which allow this to be communicated to the client.
>
> This patch
> - introduces a new state-id status SC_STATUS_ADMIN_REVOKED
> which can be set on open, lock, or delegation state.
> - reports NFS4ERR_ADMIN_REVOKED when these are accessed
> - introduces a per-client counter of these states and returns
> SEQ4_STATUS_ADMIN_STATE_REVOKED when the counter is not zero.
> Decrements this when freeing any admin-revoked state.
> - introduces stub code to find all interesting states for a given
> superblock so they can be revoked via the 'unlock_filesystem'
> file in /proc/fs/nfsd/
> No actual states are handled yet.
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
> fs/nfsd/nfs4state.c | 85 ++++++++++++++++++++++++++++++++++++++++++++-
> fs/nfsd/nfsctl.c | 1 +
> fs/nfsd/nfsd.h | 1 +
> fs/nfsd/state.h | 10 ++++++
> fs/nfsd/trace.h | 3 +-
> 5 files changed, 98 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 6bccdd0af814..8db224906864 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1210,6 +1210,8 @@ nfs4_put_stid(struct nfs4_stid *s)
> return;
> }
> idr_remove(&clp->cl_stateids, s->sc_stateid.si_opaque.so_id);
> + if (s->sc_status & SC_STATUS_ADMIN_REVOKED)
> + atomic_dec(&s->sc_client->cl_admin_revoked);
> nfs4_free_cpntf_statelist(clp->net, s);
> spin_unlock(&clp->cl_lock);
> s->sc_free(s);
> @@ -1529,6 +1531,8 @@ static void put_ol_stateid_locked(struct nfs4_ol_stateid *stp,
> }
>
> idr_remove(&clp->cl_stateids, s->sc_stateid.si_opaque.so_id);
> + if (s->sc_status & SC_STATUS_ADMIN_REVOKED)
> + atomic_dec(&s->sc_client->cl_admin_revoked);
> list_add(&stp->st_locks, reaplist);
> }
>
> @@ -1674,6 +1678,68 @@ static void release_openowner(struct nfs4_openowner *oo)
> nfs4_put_stateowner(&oo->oo_owner);
> }
>
> +static struct nfs4_stid *find_one_sb_stid(struct nfs4_client *clp,
> + struct super_block *sb,
> + unsigned int sc_types)
> +{
> + unsigned long id, tmp;
> + struct nfs4_stid *stid;
> +
> + spin_lock(&clp->cl_lock);
> + idr_for_each_entry_ul(&clp->cl_stateids, stid, tmp, id)
> + if ((stid->sc_type & sc_types) &&
> + stid->sc_status == 0 &&
> + stid->sc_file->fi_inode->i_sb == sb) {
> + refcount_inc(&stid->sc_count);
> + break;
> + }
> + spin_unlock(&clp->cl_lock);
> + return stid;
> +}
> +
> +/**
> + * nfsd4_revoke_states - revoke all nfsv4 states associated with given filesystem
> + * @net - used to identify instance of nfsd (there is one per net namespace)
> + * @sb - super_block used to identify target filesystem
> + *
> + * All nfs4 states (open, lock, delegation, layout) held by the server instance
> + * and associated with a file on the given filesystem will be revoked resulting
> + * in any files being closed and so all references from nfsd to the filesystem
> + * being released. Thus nfsd will no longer prevent the filesystem from being
> + * unmounted.
> + *
> + * The clients which own the states will subsequently being notified that the
> + * states have been "admin-revoked".
> + */
> +void nfsd4_revoke_states(struct net *net, struct super_block *sb)
> +{
> + struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> + unsigned int idhashval;
> + unsigned int sc_types;
> +
> + sc_types = 0;
> +
> + spin_lock(&nn->client_lock);
> + for (idhashval = 0; idhashval < CLIENT_HASH_MASK; idhashval++) {
> + struct list_head *head = &nn->conf_id_hashtbl[idhashval];
> + struct nfs4_client *clp;
> + retry:
> + list_for_each_entry(clp, head, cl_idhash) {
> + struct nfs4_stid *stid = find_one_sb_stid(clp, sb,
> + sc_types);
> + if (stid) {
> + spin_unlock(&nn->client_lock);
> + switch (stid->sc_type) {
> + }
> + nfs4_put_stid(stid);
> + spin_lock(&nn->client_lock);
> + goto retry;
> + }
> + }
> + }
> + spin_unlock(&nn->client_lock);
> +}
> +
> static inline int
> hash_sessionid(struct nfs4_sessionid *sessionid)
> {
> @@ -2545,6 +2611,8 @@ static int client_info_show(struct seq_file *m, void *v)
> }
> seq_printf(m, "callback state: %s\n", cb_state2str(clp->cl_cb_state));
> seq_printf(m, "callback address: %pISpc\n", &clp->cl_cb_conn.cb_addr);
> + seq_printf(m, "admin-revoked states: %d\n",
> + atomic_read(&clp->cl_admin_revoked));
> drop_client(clp);
>
> return 0;
> @@ -4058,6 +4126,8 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> }
> if (!list_empty(&clp->cl_revoked))
> seq->status_flags |= SEQ4_STATUS_RECALLABLE_STATE_REVOKED;
> + if (atomic_read(&clp->cl_admin_revoked))
> + seq->status_flags |= SEQ4_STATUS_ADMIN_STATE_REVOKED;
> out_no_session:
> if (conn)
> free_conn(conn);
> @@ -4546,7 +4616,9 @@ nfsd4_verify_open_stid(struct nfs4_stid *s)
> {
> __be32 ret = nfs_ok;
>
> - if (s->sc_status & SC_STATUS_REVOKED)
> + if (s->sc_status & SC_STATUS_ADMIN_REVOKED)
> + ret = nfserr_admin_revoked;
> + else if (s->sc_status & SC_STATUS_REVOKED)
> ret = nfserr_deleg_revoked;
> else if (s->sc_status & SC_STATUS_CLOSED)
> ret = nfserr_bad_stateid;
> @@ -5137,6 +5209,11 @@ nfs4_check_deleg(struct nfs4_client *cl, struct nfsd4_open *open,
> deleg = find_deleg_stateid(cl, &open->op_delegate_stateid);
> if (deleg == NULL)
> goto out;
> + if (deleg->dl_stid.sc_status & SC_STATUS_ADMIN_REVOKED) {
> + nfs4_put_stid(&deleg->dl_stid);
> + status = nfserr_admin_revoked;
> + goto out;
> + }
> if (deleg->dl_stid.sc_status & SC_STATUS_REVOKED) {
> nfs4_put_stid(&deleg->dl_stid);
> status = nfserr_deleg_revoked;
> @@ -6443,6 +6520,8 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
> */
> statusmask |= SC_STATUS_REVOKED;
>
> + statusmask |= SC_STATUS_ADMIN_REVOKED;
> +
> if (ZERO_STATEID(stateid) || ONE_STATEID(stateid) ||
> CLOSE_STATEID(stateid))
> return nfserr_bad_stateid;
> @@ -6461,6 +6540,10 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
> nfs4_put_stid(stid);
> return nfserr_deleg_revoked;
> }
> + if (stid->sc_status & SC_STATUS_ADMIN_REVOKED) {
> + nfs4_put_stid(stid);
> + return nfserr_admin_revoked;
> + }
> *s = stid;
> return nfs_ok;
> }
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index f206ca32e7f5..4bae65e8d28a 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -281,6 +281,7 @@ static ssize_t write_unlock_fs(struct file *file, char *buf, size_t size)
> * 3. Is that directory the root of an exported file system?
> */
> error = nlmsvc_unlock_all_by_sb(path.dentry->d_sb);
> + nfsd4_revoke_states(netns(file), path.dentry->d_sb);
>
> path_put(&path);
> return error;
> diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
> index 304e9728b929..9a86fe8a39ef 100644
> --- a/fs/nfsd/nfsd.h
> +++ b/fs/nfsd/nfsd.h
> @@ -274,6 +274,7 @@ void nfsd_lockd_shutdown(void);
> #define nfserr_no_grace cpu_to_be32(NFSERR_NO_GRACE)
> #define nfserr_reclaim_bad cpu_to_be32(NFSERR_RECLAIM_BAD)
> #define nfserr_badname cpu_to_be32(NFSERR_BADNAME)
> +#define nfserr_admin_revoked cpu_to_be32(NFS4ERR_ADMIN_REVOKED)
> #define nfserr_cb_path_down cpu_to_be32(NFSERR_CB_PATH_DOWN)
> #define nfserr_locked cpu_to_be32(NFSERR_LOCKED)
> #define nfserr_wrongsec cpu_to_be32(NFSERR_WRONGSEC)
> diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
> index ffc8920d0558..7fa83265ad9a 100644
> --- a/fs/nfsd/state.h
> +++ b/fs/nfsd/state.h
> @@ -112,6 +112,7 @@ struct nfs4_stid {
> #define SC_STATUS_CLOSED BIT(0)
> /* For a deleg stateid kept around only to process free_stateid's: */
> #define SC_STATUS_REVOKED BIT(1)
> +#define SC_STATUS_ADMIN_REVOKED BIT(2)
> unsigned short sc_status;
>
> struct list_head sc_cp_list;
> @@ -367,6 +368,7 @@ struct nfs4_client {
> clientid_t cl_clientid; /* generated by server */
> nfs4_verifier cl_confirm; /* generated by server */
> u32 cl_minorversion;
> + atomic_t cl_admin_revoked; /* count of admin-revoked states */
> /* NFSv4.1 client implementation id: */
> struct xdr_netobj cl_nii_domain;
> struct xdr_netobj cl_nii_name;
> @@ -730,6 +732,14 @@ static inline void get_nfs4_file(struct nfs4_file *fi)
> }
> struct nfsd_file *find_any_file(struct nfs4_file *f);
>
> +#ifdef CONFIG_NFSD_V4
> +void nfsd4_revoke_states(struct net *net, struct super_block *sb);
> +#else
> +static inline void nfsd4_revoke_states(struct net *net, struct super_block *sb)
> +{
> +}
> +#endif
> +
> /* grace period management */
> void nfsd4_end_grace(struct nfsd_net *nn);
>
> diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
> index fe08ca18b647..5c58da9f86b7 100644
> --- a/fs/nfsd/trace.h
> +++ b/fs/nfsd/trace.h
> @@ -651,7 +651,8 @@ DEFINE_STATESEQID_EVENT(open_confirm);
> #define show_stid_status(x) \
> __print_flags(x, "|", \
> { SC_STATUS_CLOSED, "CLOSED" }, \
> - { SC_STATUS_REVOKED, "REVOKED" }) \
> + { SC_STATUS_REVOKED, "REVOKED" }, \
> + { SC_STATUS_ADMIN_REVOKED, "ADMIN_REVOKED" })
>
> DECLARE_EVENT_CLASS(nfsd_stid_class,
> TP_PROTO(
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
