// SPDX-License-Identifier: GPL-2.0-only /* * fs/nfs/nfs4session.c * * Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com> * */ #include <linux/kernel.h> #include <linux/errno.h> #include <linux/string.h> #include <linux/printk.h> #include <linux/slab.h> #include <linux/sunrpc/sched.h> #include <linux/sunrpc/bc_xprt.h> #include <linux/nfs.h> #include <linux/nfs4.h> #include <linux/nfs_fs.h> #include <linux/module.h> #include "nfs4_fs.h" #include "internal.h" #include "nfs4session.h" #include "callback.h" #define NFSDBG_FACILITY NFSDBG_STATE static void nfs4_init_slot_table(struct nfs4_slot_table *tbl, const char *queue) { tbl->highest_used_slotid = NFS4_NO_SLOT; spin_lock_init(&tbl->slot_tbl_lock); rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, queue); init_waitqueue_head(&tbl->slot_waitq); init_completion(&tbl->complete); } /* * nfs4_shrink_slot_table - free retired slots from the slot table */ static void nfs4_shrink_slot_table(struct nfs4_slot_table *tbl, u32 newsize) { struct nfs4_slot **p; if (newsize >= tbl->max_slots) return; p = &tbl->slots; while (newsize--) p = &(*p)->next; while (*p) { struct nfs4_slot *slot = *p; *p = slot->next; kfree(slot); tbl->max_slots--; } } /** * nfs4_slot_tbl_drain_complete - wake waiters when drain is complete * @tbl: controlling slot table * */ void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl) { if (nfs4_slot_tbl_draining(tbl)) complete(&tbl->complete); } /* * nfs4_free_slot - free a slot and efficiently update slot table. * * freeing a slot is trivially done by clearing its respective bit * in the bitmap. * If the freed slotid equals highest_used_slotid we want to update it * so that the server would be able to size down the slot table if needed, * otherwise we know that the highest_used_slotid is still in use. * When updating highest_used_slotid there may be "holes" in the bitmap * so we need to scan down from highest_used_slotid to 0 looking for the now * highest slotid in use. * If none found, highest_used_slotid is set to NFS4_NO_SLOT. * * Must be called while holding tbl->slot_tbl_lock */ void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot) { u32 slotid = slot->slot_nr; /* clear used bit in bitmap */ __clear_bit(slotid, tbl->used_slots); /* update highest_used_slotid when it is freed */ if (slotid == tbl->highest_used_slotid) { u32 new_max = find_last_bit(tbl->used_slots, slotid); if (new_max < slotid) tbl->highest_used_slotid = new_max; else { tbl->highest_used_slotid = NFS4_NO_SLOT; nfs4_slot_tbl_drain_complete(tbl); } } dprintk("%s: slotid %u highest_used_slotid %u\n", __func__, slotid, tbl->highest_used_slotid); } static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table *tbl, u32 slotid, u32 seq_init, gfp_t gfp_mask) { struct nfs4_slot *slot; slot = kzalloc(sizeof(*slot), gfp_mask); if (slot) { slot->table = tbl; slot->slot_nr = slotid; slot->seq_nr = seq_init; slot->seq_nr_highest_sent = seq_init; slot->seq_nr_last_acked = seq_init - 1; } return slot; } static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table *tbl, u32 slotid, u32 seq_init, gfp_t gfp_mask) { struct nfs4_slot **p, *slot; p = &tbl->slots; for (;;) { if (*p == NULL) { *p = nfs4_new_slot(tbl, tbl->max_slots, seq_init, gfp_mask); if (*p == NULL) break; tbl->max_slots++; } slot = *p; if (slot->slot_nr == slotid) return slot; p = &slot->next; } return ERR_PTR(-ENOMEM); } static void nfs4_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot) { u32 slotid = slot->slot_nr; __set_bit(slotid, tbl->used_slots); if (slotid > tbl->highest_used_slotid || tbl->highest_used_slotid == NFS4_NO_SLOT) tbl->highest_used_slotid = slotid; slot->generation = tbl->generation; } /* * nfs4_try_to_lock_slot - Given a slot try to allocate it * * Note: must be called with the slot_tbl_lock held. */ bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot) { if (nfs4_test_locked_slot(tbl, slot->slot_nr)) return false; nfs4_lock_slot(tbl, slot); return true; } /* * nfs4_lookup_slot - Find a slot but don't allocate it * * Note: must be called with the slot_tbl_lock held. */ struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid) { if (slotid <= tbl->max_slotid) return nfs4_find_or_create_slot(tbl, slotid, 0, GFP_NOWAIT); return ERR_PTR(-E2BIG); } static int nfs4_slot_get_seqid(struct nfs4_slot_table *tbl, u32 slotid, u32 *seq_nr) __must_hold(&tbl->slot_tbl_lock) { struct nfs4_slot *slot; int ret; slot = nfs4_lookup_slot(tbl, slotid); ret = PTR_ERR_OR_ZERO(slot); if (!ret) *seq_nr = slot->seq_nr; return ret; } /* * nfs4_slot_seqid_in_use - test if a slot sequence id is still in use * * Given a slot table, slot id and sequence number, determine if the * RPC call in question is still in flight. This function is mainly * intended for use by the callback channel. */ static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl, u32 slotid, u32 seq_nr) { u32 cur_seq = 0; bool ret = false; spin_lock(&tbl->slot_tbl_lock); if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 && cur_seq == seq_nr && test_bit(slotid, tbl->used_slots)) ret = true; spin_unlock(&tbl->slot_tbl_lock); return ret; } /* * nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete * * Given a slot table, slot id and sequence number, wait until the * corresponding RPC call completes. This function is mainly * intended for use by the callback channel. */ int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl, u32 slotid, u32 seq_nr, unsigned long timeout) { if (wait_event_timeout(tbl->slot_waitq, !nfs4_slot_seqid_in_use(tbl, slotid, seq_nr), timeout) == 0) return -ETIMEDOUT; return 0; } /* * nfs4_alloc_slot - efficiently look for a free slot * * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap. * If found, we mark the slot as used, update the highest_used_slotid, * and respectively set up the sequence operation args. * * Note: must be called with under the slot_tbl_lock. */ struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl) { struct nfs4_slot *ret = ERR_PTR(-EBUSY); u32 slotid; dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n", __func__, tbl->used_slots[0], tbl->highest_used_slotid, tbl->max_slotid + 1); slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1); if (slotid <= tbl->max_slotid) { ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT); if (!IS_ERR(ret)) nfs4_lock_slot(tbl, ret); } dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n", __func__, tbl->used_slots[0], tbl->highest_used_slotid, !IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT); return ret; } static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl, u32 max_reqs, u32 ivalue) { if (max_reqs <= tbl->max_slots) return 0; if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS))) return 0; return -ENOMEM; } static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl, u32 server_highest_slotid, u32 ivalue) { struct nfs4_slot **p; nfs4_shrink_slot_table(tbl, server_highest_slotid + 1); p = &tbl->slots; while (*p) { (*p)->seq_nr = ivalue; (*p)->seq_nr_highest_sent = ivalue; (*p)->seq_nr_last_acked = ivalue - 1; p = &(*p)->next; } tbl->highest_used_slotid = NFS4_NO_SLOT; tbl->target_highest_slotid = server_highest_slotid; tbl->server_highest_slotid = server_highest_slotid; tbl->d_target_highest_slotid = 0; tbl->d2_target_highest_slotid = 0; tbl->max_slotid = server_highest_slotid; } /* * (re)Initialise a slot table */ static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl, u32 max_reqs, u32 ivalue) { int ret; dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__, max_reqs, tbl->max_slots); if (max_reqs > NFS4_MAX_SLOT_TABLE) max_reqs = NFS4_MAX_SLOT_TABLE; ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue); if (ret) goto out; spin_lock(&tbl->slot_tbl_lock); nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue); spin_unlock(&tbl->slot_tbl_lock); dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__, tbl, tbl->slots, tbl->max_slots); out: dprintk("<-- %s: return %d\n", __func__, ret); return ret; } /* * nfs4_release_slot_table - release all slot table entries */ static void nfs4_release_slot_table(struct nfs4_slot_table *tbl) { nfs4_shrink_slot_table(tbl, 0); } /** * nfs4_shutdown_slot_table - release resources attached to a slot table * @tbl: slot table to shut down * */ void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl) { nfs4_release_slot_table(tbl); rpc_destroy_wait_queue(&tbl->slot_tbl_waitq); } /** * nfs4_setup_slot_table - prepare a stand-alone slot table for use * @tbl: slot table to set up * @max_reqs: maximum number of requests allowed * @queue: name to give RPC wait queue * * Returns zero on success, or a negative errno. */ int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs, const char *queue) { nfs4_init_slot_table(tbl, queue); return nfs4_realloc_slot_table(tbl, max_reqs, 0); } static bool nfs41_assign_slot(struct rpc_task *task, void *pslot) { struct nfs4_sequence_args *args = task->tk_msg.rpc_argp; struct nfs4_sequence_res *res = task->tk_msg.rpc_resp; struct nfs4_slot *slot = pslot; struct nfs4_slot_table *tbl = slot->table; if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged) return false; slot->generation = tbl->generation; args->sa_slot = slot; res->sr_timestamp = jiffies; res->sr_slot = slot; res->sr_status_flags = 0; res->sr_status = 1; return true; } static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot) { if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot)) return true; return false; } bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot) { if (slot->slot_nr > tbl->max_slotid) return false; return __nfs41_wake_and_assign_slot(tbl, slot); } static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl) { struct nfs4_slot *slot = nfs4_alloc_slot(tbl); if (!IS_ERR(slot)) { bool ret = __nfs41_wake_and_assign_slot(tbl, slot); if (ret) return ret; nfs4_free_slot(tbl, slot); } return false; } void nfs41_wake_slot_table(struct nfs4_slot_table *tbl) { for (;;) { if (!nfs41_try_wake_next_slot_table_entry(tbl)) break; } } #if defined(CONFIG_NFS_V4_1) static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl, u32 target_highest_slotid) { u32 max_slotid; max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid); if (max_slotid > tbl->server_highest_slotid) max_slotid = tbl->server_highest_slotid; if (max_slotid > tbl->target_highest_slotid) max_slotid = tbl->target_highest_slotid; tbl->max_slotid = max_slotid; nfs41_wake_slot_table(tbl); } /* Update the client's idea of target_highest_slotid */ static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl, u32 target_highest_slotid) { if (tbl->target_highest_slotid == target_highest_slotid) return; tbl->target_highest_slotid = target_highest_slotid; tbl->generation++; } void nfs41_set_target_slotid(struct nfs4_slot_table *tbl, u32 target_highest_slotid) { spin_lock(&tbl->slot_tbl_lock); nfs41_set_target_slotid_locked(tbl, target_highest_slotid); tbl->d_target_highest_slotid = 0; tbl->d2_target_highest_slotid = 0; nfs41_set_max_slotid_locked(tbl, target_highest_slotid); spin_unlock(&tbl->slot_tbl_lock); } static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl, u32 highest_slotid) { if (tbl->server_highest_slotid == highest_slotid) return; if (tbl->highest_used_slotid > highest_slotid) return; /* Deallocate slots */ nfs4_shrink_slot_table(tbl, highest_slotid + 1); tbl->server_highest_slotid = highest_slotid; } static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2) { s1 -= s2; if (s1 == 0) return 0; if (s1 < 0) return (s1 - 1) >> 1; return (s1 + 1) >> 1; } static int nfs41_sign_s32(s32 s1) { if (s1 > 0) return 1; if (s1 < 0) return -1; return 0; } static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2) { if (!s1 || !s2) return true; return nfs41_sign_s32(s1) == nfs41_sign_s32(s2); } /* Try to eliminate outliers by checking for sharp changes in the * derivatives and second derivatives */ static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl, u32 new_target) { s32 d_target, d2_target; bool ret = true; d_target = nfs41_derivative_target_slotid(new_target, tbl->target_highest_slotid); d2_target = nfs41_derivative_target_slotid(d_target, tbl->d_target_highest_slotid); /* Is first derivative same sign? */ if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid)) ret = false; /* Is second derivative same sign? */ if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid)) ret = false; tbl->d_target_highest_slotid = d_target; tbl->d2_target_highest_slotid = d2_target; return ret; } void nfs41_update_target_slotid(struct nfs4_slot_table *tbl, struct nfs4_slot *slot, struct nfs4_sequence_res *res) { spin_lock(&tbl->slot_tbl_lock); if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid)) nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid); if (tbl->generation == slot->generation) nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid); nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid); spin_unlock(&tbl->slot_tbl_lock); } static void nfs4_release_session_slot_tables(struct nfs4_session *session) { nfs4_release_slot_table(&session->fc_slot_table); nfs4_release_slot_table(&session->bc_slot_table); } /* * Initialize or reset the forechannel and backchannel tables */ int nfs4_setup_session_slot_tables(struct nfs4_session *ses) { struct nfs4_slot_table *tbl; int status; dprintk("--> %s\n", __func__); /* Fore channel */ tbl = &ses->fc_slot_table; tbl->session = ses; status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1); if (status || !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */ return status; /* Back channel */ tbl = &ses->bc_slot_table; tbl->session = ses; status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0); if (status && tbl->slots == NULL) /* Fore and back channel share a connection so get * both slot tables or neither */ nfs4_release_session_slot_tables(ses); return status; } struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp) { struct nfs4_session *session; session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS); if (!session) return NULL; nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table"); nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table"); session->session_state = 1<<NFS4_SESSION_INITING; session->clp = clp; return session; } static void nfs4_destroy_session_slot_tables(struct nfs4_session *session) { nfs4_shutdown_slot_table(&session->fc_slot_table); nfs4_shutdown_slot_table(&session->bc_slot_table); } void nfs4_destroy_session(struct nfs4_session *session) { struct rpc_xprt *xprt; const struct cred *cred; cred = nfs4_get_clid_cred(session->clp); nfs4_proc_destroy_session(session, cred); put_cred(cred); rcu_read_lock(); xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt); rcu_read_unlock(); dprintk("%s Destroy backchannel for xprt %p\n", __func__, xprt); xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS); nfs4_destroy_session_slot_tables(session); kfree(session); } /* * With sessions, the client is not marked ready until after a * successful EXCHANGE_ID and CREATE_SESSION. * * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate * other versions of NFS can be tried. */ static int nfs41_check_session_ready(struct nfs_client *clp) { int ret; if (clp->cl_cons_state == NFS_CS_SESSION_INITING) { ret = nfs4_client_recover_expired_lease(clp); if (ret) return ret; } if (clp->cl_cons_state < NFS_CS_READY) return -EPROTONOSUPPORT; smp_rmb(); return 0; } int nfs4_init_session(struct nfs_client *clp) { if (!nfs4_has_session(clp)) return 0; clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state); return nfs41_check_session_ready(clp); } int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time) { struct nfs4_session *session = clp->cl_session; int ret; spin_lock(&clp->cl_lock); if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) { /* * Do not set NFS_CS_CHECK_LEASE_TIME instead set the * DS lease to be equal to the MDS lease. */ clp->cl_lease_time = lease_time; clp->cl_last_renewal = jiffies; } spin_unlock(&clp->cl_lock); ret = nfs41_check_session_ready(clp); if (ret) return ret; /* Test for the DS role */ if (!is_ds_client(clp)) return -ENODEV; return 0; } EXPORT_SYMBOL_GPL(nfs4_init_ds_session); #endif /* defined(CONFIG_NFS_V4_1) */