--- /dev/null
+/*
+ * 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_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;
+ }
+ 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);
+}
+
+/*
+ * 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)
+ goto out;
+ ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
+ if (IS_ERR(ret))
+ goto out;
+ __set_bit(slotid, tbl->used_slots);
+ if (slotid > tbl->highest_used_slotid ||
+ tbl->highest_used_slotid == NFS4_NO_SLOT)
+ tbl->highest_used_slotid = slotid;
+ ret->generation = tbl->generation;
+
+out:
+ 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)->interrupted = 0;
+ 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;
+ struct rpc_cred *cred;
+
+ cred = nfs4_get_clid_cred(session->clp);
+ nfs4_proc_destroy_session(session, cred);
+ if (cred)
+ put_rpccred(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) */
Code Review / kvmfornfv.git / blobdiff