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1/*
2 * fs/nfs/nfs4session.c
3 *
4 * Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>
5 *
6 */
7#include <linux/kernel.h>
8#include <linux/errno.h>
9#include <linux/string.h>
10#include <linux/printk.h>
11#include <linux/slab.h>
12#include <linux/sunrpc/sched.h>
13#include <linux/sunrpc/bc_xprt.h>
14#include <linux/nfs.h>
15#include <linux/nfs4.h>
16#include <linux/nfs_fs.h>
17#include <linux/module.h>
18
19#include "nfs4_fs.h"
20#include "internal.h"
21#include "nfs4session.h"
22#include "callback.h"
23
24#define NFSDBG_FACILITY NFSDBG_STATE
25
26static void nfs4_init_slot_table(struct nfs4_slot_table *tbl, const char *queue)
27{
28 tbl->highest_used_slotid = NFS4_NO_SLOT;
29 spin_lock_init(&tbl->slot_tbl_lock);
30 rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, queue);
31 init_waitqueue_head(&tbl->slot_waitq);
32 init_completion(&tbl->complete);
33}
34
35/*
36 * nfs4_shrink_slot_table - free retired slots from the slot table
37 */
38static void nfs4_shrink_slot_table(struct nfs4_slot_table *tbl, u32 newsize)
39{
40 struct nfs4_slot **p;
41 if (newsize >= tbl->max_slots)
42 return;
43
44 p = &tbl->slots;
45 while (newsize--)
46 p = &(*p)->next;
47 while (*p) {
48 struct nfs4_slot *slot = *p;
49
50 *p = slot->next;
51 kfree(slot);
52 tbl->max_slots--;
53 }
54}
55
56/**
57 * nfs4_slot_tbl_drain_complete - wake waiters when drain is complete
58 * @tbl - controlling slot table
59 *
60 */
61void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl)
62{
63 if (nfs4_slot_tbl_draining(tbl))
64 complete(&tbl->complete);
65}
66
67/*
68 * nfs4_free_slot - free a slot and efficiently update slot table.
69 *
70 * freeing a slot is trivially done by clearing its respective bit
71 * in the bitmap.
72 * If the freed slotid equals highest_used_slotid we want to update it
73 * so that the server would be able to size down the slot table if needed,
74 * otherwise we know that the highest_used_slotid is still in use.
75 * When updating highest_used_slotid there may be "holes" in the bitmap
76 * so we need to scan down from highest_used_slotid to 0 looking for the now
77 * highest slotid in use.
78 * If none found, highest_used_slotid is set to NFS4_NO_SLOT.
79 *
80 * Must be called while holding tbl->slot_tbl_lock
81 */
82void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
83{
84 u32 slotid = slot->slot_nr;
85
86 /* clear used bit in bitmap */
87 __clear_bit(slotid, tbl->used_slots);
88
89 /* update highest_used_slotid when it is freed */
90 if (slotid == tbl->highest_used_slotid) {
91 u32 new_max = find_last_bit(tbl->used_slots, slotid);
92 if (new_max < slotid)
93 tbl->highest_used_slotid = new_max;
94 else {
95 tbl->highest_used_slotid = NFS4_NO_SLOT;
96 nfs4_slot_tbl_drain_complete(tbl);
97 }
98 }
99 dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
100 slotid, tbl->highest_used_slotid);
101}
102
103static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table *tbl,
104 u32 slotid, u32 seq_init, gfp_t gfp_mask)
105{
106 struct nfs4_slot *slot;
107
108 slot = kzalloc(sizeof(*slot), gfp_mask);
109 if (slot) {
110 slot->table = tbl;
111 slot->slot_nr = slotid;
112 slot->seq_nr = seq_init;
113 }
114 return slot;
115}
116
117static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table *tbl,
118 u32 slotid, u32 seq_init, gfp_t gfp_mask)
119{
120 struct nfs4_slot **p, *slot;
121
122 p = &tbl->slots;
123 for (;;) {
124 if (*p == NULL) {
125 *p = nfs4_new_slot(tbl, tbl->max_slots,
126 seq_init, gfp_mask);
127 if (*p == NULL)
128 break;
129 tbl->max_slots++;
130 }
131 slot = *p;
132 if (slot->slot_nr == slotid)
133 return slot;
134 p = &slot->next;
135 }
136 return ERR_PTR(-ENOMEM);
137}
138
139static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
140 struct nfs4_slot *slot)
141{
142 u32 slotid = slot->slot_nr;
143
144 __set_bit(slotid, tbl->used_slots);
145 if (slotid > tbl->highest_used_slotid ||
146 tbl->highest_used_slotid == NFS4_NO_SLOT)
147 tbl->highest_used_slotid = slotid;
148 slot->generation = tbl->generation;
149}
150
151/*
152 * nfs4_try_to_lock_slot - Given a slot try to allocate it
153 *
154 * Note: must be called with the slot_tbl_lock held.
155 */
156bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
157{
158 if (nfs4_test_locked_slot(tbl, slot->slot_nr))
159 return false;
160 nfs4_lock_slot(tbl, slot);
161 return true;
162}
163
164/*
165 * nfs4_lookup_slot - Find a slot but don't allocate it
166 *
167 * Note: must be called with the slot_tbl_lock held.
168 */
169struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid)
170{
171 if (slotid <= tbl->max_slotid)
172 return nfs4_find_or_create_slot(tbl, slotid, 0, GFP_NOWAIT);
173 return ERR_PTR(-E2BIG);
174}
175
176static int nfs4_slot_get_seqid(struct nfs4_slot_table *tbl, u32 slotid,
177 u32 *seq_nr)
178 __must_hold(&tbl->slot_tbl_lock)
179{
180 struct nfs4_slot *slot;
181 int ret;
182
183 slot = nfs4_lookup_slot(tbl, slotid);
184 ret = PTR_ERR_OR_ZERO(slot);
185 if (!ret)
186 *seq_nr = slot->seq_nr;
187
188 return ret;
189}
190
191/*
192 * nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
193 *
194 * Given a slot table, slot id and sequence number, determine if the
195 * RPC call in question is still in flight. This function is mainly
196 * intended for use by the callback channel.
197 */
198static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl,
199 u32 slotid, u32 seq_nr)
200{
201 u32 cur_seq = 0;
202 bool ret = false;
203
204 spin_lock(&tbl->slot_tbl_lock);
205 if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
206 cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
207 ret = true;
208 spin_unlock(&tbl->slot_tbl_lock);
209 return ret;
210}
211
212/*
213 * nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete
214 *
215 * Given a slot table, slot id and sequence number, wait until the
216 * corresponding RPC call completes. This function is mainly
217 * intended for use by the callback channel.
218 */
219int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
220 u32 slotid, u32 seq_nr,
221 unsigned long timeout)
222{
223 if (wait_event_timeout(tbl->slot_waitq,
224 !nfs4_slot_seqid_in_use(tbl, slotid, seq_nr),
225 timeout) == 0)
226 return -ETIMEDOUT;
227 return 0;
228}
229
230/*
231 * nfs4_alloc_slot - efficiently look for a free slot
232 *
233 * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
234 * If found, we mark the slot as used, update the highest_used_slotid,
235 * and respectively set up the sequence operation args.
236 *
237 * Note: must be called with under the slot_tbl_lock.
238 */
239struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
240{
241 struct nfs4_slot *ret = ERR_PTR(-EBUSY);
242 u32 slotid;
243
244 dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
245 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
246 tbl->max_slotid + 1);
247 slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
248 if (slotid <= tbl->max_slotid) {
249 ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
250 if (!IS_ERR(ret))
251 nfs4_lock_slot(tbl, ret);
252 }
253 dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
254 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
255 !IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
256 return ret;
257}
258
259static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
260 u32 max_reqs, u32 ivalue)
261{
262 if (max_reqs <= tbl->max_slots)
263 return 0;
264 if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
265 return 0;
266 return -ENOMEM;
267}
268
269static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
270 u32 server_highest_slotid,
271 u32 ivalue)
272{
273 struct nfs4_slot **p;
274
275 nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
276 p = &tbl->slots;
277 while (*p) {
278 (*p)->seq_nr = ivalue;
279 (*p)->interrupted = 0;
280 p = &(*p)->next;
281 }
282 tbl->highest_used_slotid = NFS4_NO_SLOT;
283 tbl->target_highest_slotid = server_highest_slotid;
284 tbl->server_highest_slotid = server_highest_slotid;
285 tbl->d_target_highest_slotid = 0;
286 tbl->d2_target_highest_slotid = 0;
287 tbl->max_slotid = server_highest_slotid;
288}
289
290/*
291 * (re)Initialise a slot table
292 */
293static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
294 u32 max_reqs, u32 ivalue)
295{
296 int ret;
297
298 dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
299 max_reqs, tbl->max_slots);
300
301 if (max_reqs > NFS4_MAX_SLOT_TABLE)
302 max_reqs = NFS4_MAX_SLOT_TABLE;
303
304 ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
305 if (ret)
306 goto out;
307
308 spin_lock(&tbl->slot_tbl_lock);
309 nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
310 spin_unlock(&tbl->slot_tbl_lock);
311
312 dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
313 tbl, tbl->slots, tbl->max_slots);
314out:
315 dprintk("<-- %s: return %d\n", __func__, ret);
316 return ret;
317}
318
319/*
320 * nfs4_release_slot_table - release all slot table entries
321 */
322static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
323{
324 nfs4_shrink_slot_table(tbl, 0);
325}
326
327/**
328 * nfs4_shutdown_slot_table - release resources attached to a slot table
329 * @tbl: slot table to shut down
330 *
331 */
332void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
333{
334 nfs4_release_slot_table(tbl);
335 rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
336}
337
338/**
339 * nfs4_setup_slot_table - prepare a stand-alone slot table for use
340 * @tbl: slot table to set up
341 * @max_reqs: maximum number of requests allowed
342 * @queue: name to give RPC wait queue
343 *
344 * Returns zero on success, or a negative errno.
345 */
346int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
347 const char *queue)
348{
349 nfs4_init_slot_table(tbl, queue);
350 return nfs4_realloc_slot_table(tbl, max_reqs, 0);
351}
352
353static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
354{
355 struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
356 struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
357 struct nfs4_slot *slot = pslot;
358 struct nfs4_slot_table *tbl = slot->table;
359
360 if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
361 return false;
362 slot->generation = tbl->generation;
363 args->sa_slot = slot;
364 res->sr_timestamp = jiffies;
365 res->sr_slot = slot;
366 res->sr_status_flags = 0;
367 res->sr_status = 1;
368 return true;
369}
370
371static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
372 struct nfs4_slot *slot)
373{
374 if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
375 return true;
376 return false;
377}
378
379bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
380 struct nfs4_slot *slot)
381{
382 if (slot->slot_nr > tbl->max_slotid)
383 return false;
384 return __nfs41_wake_and_assign_slot(tbl, slot);
385}
386
387static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
388{
389 struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
390 if (!IS_ERR(slot)) {
391 bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
392 if (ret)
393 return ret;
394 nfs4_free_slot(tbl, slot);
395 }
396 return false;
397}
398
399void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
400{
401 for (;;) {
402 if (!nfs41_try_wake_next_slot_table_entry(tbl))
403 break;
404 }
405}
406
407#if defined(CONFIG_NFS_V4_1)
408
409static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
410 u32 target_highest_slotid)
411{
412 u32 max_slotid;
413
414 max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
415 if (max_slotid > tbl->server_highest_slotid)
416 max_slotid = tbl->server_highest_slotid;
417 if (max_slotid > tbl->target_highest_slotid)
418 max_slotid = tbl->target_highest_slotid;
419 tbl->max_slotid = max_slotid;
420 nfs41_wake_slot_table(tbl);
421}
422
423/* Update the client's idea of target_highest_slotid */
424static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
425 u32 target_highest_slotid)
426{
427 if (tbl->target_highest_slotid == target_highest_slotid)
428 return;
429 tbl->target_highest_slotid = target_highest_slotid;
430 tbl->generation++;
431}
432
433void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
434 u32 target_highest_slotid)
435{
436 spin_lock(&tbl->slot_tbl_lock);
437 nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
438 tbl->d_target_highest_slotid = 0;
439 tbl->d2_target_highest_slotid = 0;
440 nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
441 spin_unlock(&tbl->slot_tbl_lock);
442}
443
444static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
445 u32 highest_slotid)
446{
447 if (tbl->server_highest_slotid == highest_slotid)
448 return;
449 if (tbl->highest_used_slotid > highest_slotid)
450 return;
451 /* Deallocate slots */
452 nfs4_shrink_slot_table(tbl, highest_slotid + 1);
453 tbl->server_highest_slotid = highest_slotid;
454}
455
456static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
457{
458 s1 -= s2;
459 if (s1 == 0)
460 return 0;
461 if (s1 < 0)
462 return (s1 - 1) >> 1;
463 return (s1 + 1) >> 1;
464}
465
466static int nfs41_sign_s32(s32 s1)
467{
468 if (s1 > 0)
469 return 1;
470 if (s1 < 0)
471 return -1;
472 return 0;
473}
474
475static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
476{
477 if (!s1 || !s2)
478 return true;
479 return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
480}
481
482/* Try to eliminate outliers by checking for sharp changes in the
483 * derivatives and second derivatives
484 */
485static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
486 u32 new_target)
487{
488 s32 d_target, d2_target;
489 bool ret = true;
490
491 d_target = nfs41_derivative_target_slotid(new_target,
492 tbl->target_highest_slotid);
493 d2_target = nfs41_derivative_target_slotid(d_target,
494 tbl->d_target_highest_slotid);
495 /* Is first derivative same sign? */
496 if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
497 ret = false;
498 /* Is second derivative same sign? */
499 if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
500 ret = false;
501 tbl->d_target_highest_slotid = d_target;
502 tbl->d2_target_highest_slotid = d2_target;
503 return ret;
504}
505
506void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
507 struct nfs4_slot *slot,
508 struct nfs4_sequence_res *res)
509{
510 spin_lock(&tbl->slot_tbl_lock);
511 if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
512 nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
513 if (tbl->generation == slot->generation)
514 nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
515 nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
516 spin_unlock(&tbl->slot_tbl_lock);
517}
518
519static void nfs4_release_session_slot_tables(struct nfs4_session *session)
520{
521 nfs4_release_slot_table(&session->fc_slot_table);
522 nfs4_release_slot_table(&session->bc_slot_table);
523}
524
525/*
526 * Initialize or reset the forechannel and backchannel tables
527 */
528int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
529{
530 struct nfs4_slot_table *tbl;
531 int status;
532
533 dprintk("--> %s\n", __func__);
534 /* Fore channel */
535 tbl = &ses->fc_slot_table;
536 tbl->session = ses;
537 status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
538 if (status || !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */
539 return status;
540 /* Back channel */
541 tbl = &ses->bc_slot_table;
542 tbl->session = ses;
543 status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
544 if (status && tbl->slots == NULL)
545 /* Fore and back channel share a connection so get
546 * both slot tables or neither */
547 nfs4_release_session_slot_tables(ses);
548 return status;
549}
550
551struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
552{
553 struct nfs4_session *session;
554
555 session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
556 if (!session)
557 return NULL;
558
559 nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
560 nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
561 session->session_state = 1<<NFS4_SESSION_INITING;
562
563 session->clp = clp;
564 return session;
565}
566
567static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
568{
569 nfs4_shutdown_slot_table(&session->fc_slot_table);
570 nfs4_shutdown_slot_table(&session->bc_slot_table);
571}
572
573void nfs4_destroy_session(struct nfs4_session *session)
574{
575 struct rpc_xprt *xprt;
576 struct rpc_cred *cred;
577
578 cred = nfs4_get_clid_cred(session->clp);
579 nfs4_proc_destroy_session(session, cred);
580 if (cred)
581 put_rpccred(cred);
582
583 rcu_read_lock();
584 xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
585 rcu_read_unlock();
586 dprintk("%s Destroy backchannel for xprt %p\n",
587 __func__, xprt);
588 xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
589 nfs4_destroy_session_slot_tables(session);
590 kfree(session);
591}
592
593/*
594 * With sessions, the client is not marked ready until after a
595 * successful EXCHANGE_ID and CREATE_SESSION.
596 *
597 * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
598 * other versions of NFS can be tried.
599 */
600static int nfs41_check_session_ready(struct nfs_client *clp)
601{
602 int ret;
603
604 if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
605 ret = nfs4_client_recover_expired_lease(clp);
606 if (ret)
607 return ret;
608 }
609 if (clp->cl_cons_state < NFS_CS_READY)
610 return -EPROTONOSUPPORT;
611 smp_rmb();
612 return 0;
613}
614
615int nfs4_init_session(struct nfs_client *clp)
616{
617 if (!nfs4_has_session(clp))
618 return 0;
619
620 clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
621 return nfs41_check_session_ready(clp);
622}
623
624int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
625{
626 struct nfs4_session *session = clp->cl_session;
627 int ret;
628
629 spin_lock(&clp->cl_lock);
630 if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
631 /*
632 * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
633 * DS lease to be equal to the MDS lease.
634 */
635 clp->cl_lease_time = lease_time;
636 clp->cl_last_renewal = jiffies;
637 }
638 spin_unlock(&clp->cl_lock);
639
640 ret = nfs41_check_session_ready(clp);
641 if (ret)
642 return ret;
643 /* Test for the DS role */
644 if (!is_ds_client(clp))
645 return -ENODEV;
646 return 0;
647}
648EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
649
650#endif /* defined(CONFIG_NFS_V4_1) */
1/*
2 * fs/nfs/nfs4session.c
3 *
4 * Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>
5 *
6 */
7#include <linux/kernel.h>
8#include <linux/errno.h>
9#include <linux/string.h>
10#include <linux/printk.h>
11#include <linux/slab.h>
12#include <linux/sunrpc/sched.h>
13#include <linux/sunrpc/bc_xprt.h>
14#include <linux/nfs.h>
15#include <linux/nfs4.h>
16#include <linux/nfs_fs.h>
17#include <linux/module.h>
18
19#include "nfs4_fs.h"
20#include "internal.h"
21#include "nfs4session.h"
22#include "callback.h"
23
24#define NFSDBG_FACILITY NFSDBG_STATE
25
26static void nfs4_init_slot_table(struct nfs4_slot_table *tbl, const char *queue)
27{
28 tbl->highest_used_slotid = NFS4_NO_SLOT;
29 spin_lock_init(&tbl->slot_tbl_lock);
30 rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, queue);
31 init_completion(&tbl->complete);
32}
33
34/*
35 * nfs4_shrink_slot_table - free retired slots from the slot table
36 */
37static void nfs4_shrink_slot_table(struct nfs4_slot_table *tbl, u32 newsize)
38{
39 struct nfs4_slot **p;
40 if (newsize >= tbl->max_slots)
41 return;
42
43 p = &tbl->slots;
44 while (newsize--)
45 p = &(*p)->next;
46 while (*p) {
47 struct nfs4_slot *slot = *p;
48
49 *p = slot->next;
50 kfree(slot);
51 tbl->max_slots--;
52 }
53}
54
55/**
56 * nfs4_slot_tbl_drain_complete - wake waiters when drain is complete
57 * @tbl - controlling slot table
58 *
59 */
60void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl)
61{
62 if (nfs4_slot_tbl_draining(tbl))
63 complete(&tbl->complete);
64}
65
66/*
67 * nfs4_free_slot - free a slot and efficiently update slot table.
68 *
69 * freeing a slot is trivially done by clearing its respective bit
70 * in the bitmap.
71 * If the freed slotid equals highest_used_slotid we want to update it
72 * so that the server would be able to size down the slot table if needed,
73 * otherwise we know that the highest_used_slotid is still in use.
74 * When updating highest_used_slotid there may be "holes" in the bitmap
75 * so we need to scan down from highest_used_slotid to 0 looking for the now
76 * highest slotid in use.
77 * If none found, highest_used_slotid is set to NFS4_NO_SLOT.
78 *
79 * Must be called while holding tbl->slot_tbl_lock
80 */
81void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
82{
83 u32 slotid = slot->slot_nr;
84
85 /* clear used bit in bitmap */
86 __clear_bit(slotid, tbl->used_slots);
87
88 /* update highest_used_slotid when it is freed */
89 if (slotid == tbl->highest_used_slotid) {
90 u32 new_max = find_last_bit(tbl->used_slots, slotid);
91 if (new_max < slotid)
92 tbl->highest_used_slotid = new_max;
93 else {
94 tbl->highest_used_slotid = NFS4_NO_SLOT;
95 nfs4_slot_tbl_drain_complete(tbl);
96 }
97 }
98 dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
99 slotid, tbl->highest_used_slotid);
100}
101
102static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table *tbl,
103 u32 slotid, u32 seq_init, gfp_t gfp_mask)
104{
105 struct nfs4_slot *slot;
106
107 slot = kzalloc(sizeof(*slot), gfp_mask);
108 if (slot) {
109 slot->table = tbl;
110 slot->slot_nr = slotid;
111 slot->seq_nr = seq_init;
112 }
113 return slot;
114}
115
116static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table *tbl,
117 u32 slotid, u32 seq_init, gfp_t gfp_mask)
118{
119 struct nfs4_slot **p, *slot;
120
121 p = &tbl->slots;
122 for (;;) {
123 if (*p == NULL) {
124 *p = nfs4_new_slot(tbl, tbl->max_slots,
125 seq_init, gfp_mask);
126 if (*p == NULL)
127 break;
128 tbl->max_slots++;
129 }
130 slot = *p;
131 if (slot->slot_nr == slotid)
132 return slot;
133 p = &slot->next;
134 }
135 return ERR_PTR(-ENOMEM);
136}
137
138/*
139 * nfs4_alloc_slot - efficiently look for a free slot
140 *
141 * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
142 * If found, we mark the slot as used, update the highest_used_slotid,
143 * and respectively set up the sequence operation args.
144 *
145 * Note: must be called with under the slot_tbl_lock.
146 */
147struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
148{
149 struct nfs4_slot *ret = ERR_PTR(-EBUSY);
150 u32 slotid;
151
152 dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
153 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
154 tbl->max_slotid + 1);
155 slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
156 if (slotid > tbl->max_slotid)
157 goto out;
158 ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
159 if (IS_ERR(ret))
160 goto out;
161 __set_bit(slotid, tbl->used_slots);
162 if (slotid > tbl->highest_used_slotid ||
163 tbl->highest_used_slotid == NFS4_NO_SLOT)
164 tbl->highest_used_slotid = slotid;
165 ret->generation = tbl->generation;
166
167out:
168 dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
169 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
170 !IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
171 return ret;
172}
173
174static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
175 u32 max_reqs, u32 ivalue)
176{
177 if (max_reqs <= tbl->max_slots)
178 return 0;
179 if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
180 return 0;
181 return -ENOMEM;
182}
183
184static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
185 u32 server_highest_slotid,
186 u32 ivalue)
187{
188 struct nfs4_slot **p;
189
190 nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
191 p = &tbl->slots;
192 while (*p) {
193 (*p)->seq_nr = ivalue;
194 (*p)->interrupted = 0;
195 p = &(*p)->next;
196 }
197 tbl->highest_used_slotid = NFS4_NO_SLOT;
198 tbl->target_highest_slotid = server_highest_slotid;
199 tbl->server_highest_slotid = server_highest_slotid;
200 tbl->d_target_highest_slotid = 0;
201 tbl->d2_target_highest_slotid = 0;
202 tbl->max_slotid = server_highest_slotid;
203}
204
205/*
206 * (re)Initialise a slot table
207 */
208static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
209 u32 max_reqs, u32 ivalue)
210{
211 int ret;
212
213 dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
214 max_reqs, tbl->max_slots);
215
216 if (max_reqs > NFS4_MAX_SLOT_TABLE)
217 max_reqs = NFS4_MAX_SLOT_TABLE;
218
219 ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
220 if (ret)
221 goto out;
222
223 spin_lock(&tbl->slot_tbl_lock);
224 nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
225 spin_unlock(&tbl->slot_tbl_lock);
226
227 dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
228 tbl, tbl->slots, tbl->max_slots);
229out:
230 dprintk("<-- %s: return %d\n", __func__, ret);
231 return ret;
232}
233
234/*
235 * nfs4_release_slot_table - release all slot table entries
236 */
237static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
238{
239 nfs4_shrink_slot_table(tbl, 0);
240}
241
242/**
243 * nfs4_shutdown_slot_table - release resources attached to a slot table
244 * @tbl: slot table to shut down
245 *
246 */
247void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
248{
249 nfs4_release_slot_table(tbl);
250 rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
251}
252
253/**
254 * nfs4_setup_slot_table - prepare a stand-alone slot table for use
255 * @tbl: slot table to set up
256 * @max_reqs: maximum number of requests allowed
257 * @queue: name to give RPC wait queue
258 *
259 * Returns zero on success, or a negative errno.
260 */
261int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
262 const char *queue)
263{
264 nfs4_init_slot_table(tbl, queue);
265 return nfs4_realloc_slot_table(tbl, max_reqs, 0);
266}
267
268static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
269{
270 struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
271 struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
272 struct nfs4_slot *slot = pslot;
273 struct nfs4_slot_table *tbl = slot->table;
274
275 if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
276 return false;
277 slot->generation = tbl->generation;
278 args->sa_slot = slot;
279 res->sr_timestamp = jiffies;
280 res->sr_slot = slot;
281 res->sr_status_flags = 0;
282 res->sr_status = 1;
283 return true;
284}
285
286static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
287 struct nfs4_slot *slot)
288{
289 if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
290 return true;
291 return false;
292}
293
294bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
295 struct nfs4_slot *slot)
296{
297 if (slot->slot_nr > tbl->max_slotid)
298 return false;
299 return __nfs41_wake_and_assign_slot(tbl, slot);
300}
301
302static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
303{
304 struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
305 if (!IS_ERR(slot)) {
306 bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
307 if (ret)
308 return ret;
309 nfs4_free_slot(tbl, slot);
310 }
311 return false;
312}
313
314void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
315{
316 for (;;) {
317 if (!nfs41_try_wake_next_slot_table_entry(tbl))
318 break;
319 }
320}
321
322#if defined(CONFIG_NFS_V4_1)
323
324static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
325 u32 target_highest_slotid)
326{
327 u32 max_slotid;
328
329 max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
330 if (max_slotid > tbl->server_highest_slotid)
331 max_slotid = tbl->server_highest_slotid;
332 if (max_slotid > tbl->target_highest_slotid)
333 max_slotid = tbl->target_highest_slotid;
334 tbl->max_slotid = max_slotid;
335 nfs41_wake_slot_table(tbl);
336}
337
338/* Update the client's idea of target_highest_slotid */
339static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
340 u32 target_highest_slotid)
341{
342 if (tbl->target_highest_slotid == target_highest_slotid)
343 return;
344 tbl->target_highest_slotid = target_highest_slotid;
345 tbl->generation++;
346}
347
348void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
349 u32 target_highest_slotid)
350{
351 spin_lock(&tbl->slot_tbl_lock);
352 nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
353 tbl->d_target_highest_slotid = 0;
354 tbl->d2_target_highest_slotid = 0;
355 nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
356 spin_unlock(&tbl->slot_tbl_lock);
357}
358
359static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
360 u32 highest_slotid)
361{
362 if (tbl->server_highest_slotid == highest_slotid)
363 return;
364 if (tbl->highest_used_slotid > highest_slotid)
365 return;
366 /* Deallocate slots */
367 nfs4_shrink_slot_table(tbl, highest_slotid + 1);
368 tbl->server_highest_slotid = highest_slotid;
369}
370
371static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
372{
373 s1 -= s2;
374 if (s1 == 0)
375 return 0;
376 if (s1 < 0)
377 return (s1 - 1) >> 1;
378 return (s1 + 1) >> 1;
379}
380
381static int nfs41_sign_s32(s32 s1)
382{
383 if (s1 > 0)
384 return 1;
385 if (s1 < 0)
386 return -1;
387 return 0;
388}
389
390static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
391{
392 if (!s1 || !s2)
393 return true;
394 return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
395}
396
397/* Try to eliminate outliers by checking for sharp changes in the
398 * derivatives and second derivatives
399 */
400static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
401 u32 new_target)
402{
403 s32 d_target, d2_target;
404 bool ret = true;
405
406 d_target = nfs41_derivative_target_slotid(new_target,
407 tbl->target_highest_slotid);
408 d2_target = nfs41_derivative_target_slotid(d_target,
409 tbl->d_target_highest_slotid);
410 /* Is first derivative same sign? */
411 if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
412 ret = false;
413 /* Is second derivative same sign? */
414 if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
415 ret = false;
416 tbl->d_target_highest_slotid = d_target;
417 tbl->d2_target_highest_slotid = d2_target;
418 return ret;
419}
420
421void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
422 struct nfs4_slot *slot,
423 struct nfs4_sequence_res *res)
424{
425 spin_lock(&tbl->slot_tbl_lock);
426 if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
427 nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
428 if (tbl->generation == slot->generation)
429 nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
430 nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
431 spin_unlock(&tbl->slot_tbl_lock);
432}
433
434static void nfs4_release_session_slot_tables(struct nfs4_session *session)
435{
436 nfs4_release_slot_table(&session->fc_slot_table);
437 nfs4_release_slot_table(&session->bc_slot_table);
438}
439
440/*
441 * Initialize or reset the forechannel and backchannel tables
442 */
443int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
444{
445 struct nfs4_slot_table *tbl;
446 int status;
447
448 dprintk("--> %s\n", __func__);
449 /* Fore channel */
450 tbl = &ses->fc_slot_table;
451 tbl->session = ses;
452 status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
453 if (status) /* -ENOMEM */
454 return status;
455 /* Back channel */
456 tbl = &ses->bc_slot_table;
457 tbl->session = ses;
458 status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
459 if (status && tbl->slots == NULL)
460 /* Fore and back channel share a connection so get
461 * both slot tables or neither */
462 nfs4_release_session_slot_tables(ses);
463 return status;
464}
465
466struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
467{
468 struct nfs4_session *session;
469
470 session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
471 if (!session)
472 return NULL;
473
474 nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
475 nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
476 session->session_state = 1<<NFS4_SESSION_INITING;
477
478 session->clp = clp;
479 return session;
480}
481
482static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
483{
484 nfs4_shutdown_slot_table(&session->fc_slot_table);
485 nfs4_shutdown_slot_table(&session->bc_slot_table);
486}
487
488void nfs4_destroy_session(struct nfs4_session *session)
489{
490 struct rpc_xprt *xprt;
491 struct rpc_cred *cred;
492
493 cred = nfs4_get_clid_cred(session->clp);
494 nfs4_proc_destroy_session(session, cred);
495 if (cred)
496 put_rpccred(cred);
497
498 rcu_read_lock();
499 xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
500 rcu_read_unlock();
501 dprintk("%s Destroy backchannel for xprt %p\n",
502 __func__, xprt);
503 xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
504 nfs4_destroy_session_slot_tables(session);
505 kfree(session);
506}
507
508/*
509 * With sessions, the client is not marked ready until after a
510 * successful EXCHANGE_ID and CREATE_SESSION.
511 *
512 * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
513 * other versions of NFS can be tried.
514 */
515static int nfs41_check_session_ready(struct nfs_client *clp)
516{
517 int ret;
518
519 if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
520 ret = nfs4_client_recover_expired_lease(clp);
521 if (ret)
522 return ret;
523 }
524 if (clp->cl_cons_state < NFS_CS_READY)
525 return -EPROTONOSUPPORT;
526 smp_rmb();
527 return 0;
528}
529
530int nfs4_init_session(struct nfs_client *clp)
531{
532 if (!nfs4_has_session(clp))
533 return 0;
534
535 clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
536 return nfs41_check_session_ready(clp);
537}
538
539int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
540{
541 struct nfs4_session *session = clp->cl_session;
542 int ret;
543
544 spin_lock(&clp->cl_lock);
545 if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
546 /*
547 * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
548 * DS lease to be equal to the MDS lease.
549 */
550 clp->cl_lease_time = lease_time;
551 clp->cl_last_renewal = jiffies;
552 }
553 spin_unlock(&clp->cl_lock);
554
555 ret = nfs41_check_session_ready(clp);
556 if (ret)
557 return ret;
558 /* Test for the DS role */
559 if (!is_ds_client(clp))
560 return -ENODEV;
561 return 0;
562}
563EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
564
565#endif /* defined(CONFIG_NFS_V4_1) */