diff options
Diffstat (limited to 'kernel/fs/nfs/nfs4session.c')
| -rw-r--r-- | kernel/fs/nfs/nfs4session.c | 565 |
1 files changed, 565 insertions, 0 deletions
diff --git a/kernel/fs/nfs/nfs4session.c b/kernel/fs/nfs/nfs4session.c new file mode 100644 index 000000000..e23366eff --- /dev/null +++ b/kernel/fs/nfs/nfs4session.c @@ -0,0 +1,565 @@ +/* + * 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) */ |