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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * fs/nfs/nfs4session.c
4 *
5 * Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>
6 *
7 */
8#include <linux/kernel.h>
9#include <linux/errno.h>
10#include <linux/string.h>
11#include <linux/printk.h>
12#include <linux/slab.h>
13#include <linux/sunrpc/sched.h>
14#include <linux/sunrpc/bc_xprt.h>
15#include <linux/nfs.h>
16#include <linux/nfs4.h>
17#include <linux/nfs_fs.h>
18#include <linux/module.h>
19
20#include "nfs4_fs.h"
21#include "internal.h"
22#include "nfs4session.h"
23#include "callback.h"
24
25#define NFSDBG_FACILITY NFSDBG_STATE
26
27static void nfs4_init_slot_table(struct nfs4_slot_table *tbl, const char *queue)
28{
29 tbl->highest_used_slotid = NFS4_NO_SLOT;
30 spin_lock_init(&tbl->slot_tbl_lock);
31 rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, queue);
32 init_waitqueue_head(&tbl->slot_waitq);
33 init_completion(&tbl->complete);
34}
35
36/*
37 * nfs4_shrink_slot_table - free retired slots from the slot table
38 */
39static void nfs4_shrink_slot_table(struct nfs4_slot_table *tbl, u32 newsize)
40{
41 struct nfs4_slot **p;
42 if (newsize >= tbl->max_slots)
43 return;
44
45 p = &tbl->slots;
46 while (newsize--)
47 p = &(*p)->next;
48 while (*p) {
49 struct nfs4_slot *slot = *p;
50
51 *p = slot->next;
52 kfree(slot);
53 tbl->max_slots--;
54 }
55}
56
57/**
58 * nfs4_slot_tbl_drain_complete - wake waiters when drain is complete
59 * @tbl: controlling slot table
60 *
61 */
62void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl)
63{
64 if (nfs4_slot_tbl_draining(tbl))
65 complete(&tbl->complete);
66}
67
68/*
69 * nfs4_free_slot - free a slot and efficiently update slot table.
70 *
71 * freeing a slot is trivially done by clearing its respective bit
72 * in the bitmap.
73 * If the freed slotid equals highest_used_slotid we want to update it
74 * so that the server would be able to size down the slot table if needed,
75 * otherwise we know that the highest_used_slotid is still in use.
76 * When updating highest_used_slotid there may be "holes" in the bitmap
77 * so we need to scan down from highest_used_slotid to 0 looking for the now
78 * highest slotid in use.
79 * If none found, highest_used_slotid is set to NFS4_NO_SLOT.
80 *
81 * Must be called while holding tbl->slot_tbl_lock
82 */
83void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
84{
85 u32 slotid = slot->slot_nr;
86
87 /* clear used bit in bitmap */
88 __clear_bit(slotid, tbl->used_slots);
89
90 /* update highest_used_slotid when it is freed */
91 if (slotid == tbl->highest_used_slotid) {
92 u32 new_max = find_last_bit(tbl->used_slots, slotid);
93 if (new_max < slotid)
94 tbl->highest_used_slotid = new_max;
95 else {
96 tbl->highest_used_slotid = NFS4_NO_SLOT;
97 nfs4_slot_tbl_drain_complete(tbl);
98 }
99 }
100 dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
101 slotid, tbl->highest_used_slotid);
102}
103
104static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table *tbl,
105 u32 slotid, u32 seq_init, gfp_t gfp_mask)
106{
107 struct nfs4_slot *slot;
108
109 slot = kzalloc(sizeof(*slot), gfp_mask);
110 if (slot) {
111 slot->table = tbl;
112 slot->slot_nr = slotid;
113 slot->seq_nr = seq_init;
114 slot->seq_nr_highest_sent = seq_init;
115 slot->seq_nr_last_acked = seq_init - 1;
116 }
117 return slot;
118}
119
120static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table *tbl,
121 u32 slotid, u32 seq_init, gfp_t gfp_mask)
122{
123 struct nfs4_slot **p, *slot;
124
125 p = &tbl->slots;
126 for (;;) {
127 if (*p == NULL) {
128 *p = nfs4_new_slot(tbl, tbl->max_slots,
129 seq_init, gfp_mask);
130 if (*p == NULL)
131 break;
132 tbl->max_slots++;
133 }
134 slot = *p;
135 if (slot->slot_nr == slotid)
136 return slot;
137 p = &slot->next;
138 }
139 return ERR_PTR(-ENOMEM);
140}
141
142static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
143 struct nfs4_slot *slot)
144{
145 u32 slotid = slot->slot_nr;
146
147 __set_bit(slotid, tbl->used_slots);
148 if (slotid > tbl->highest_used_slotid ||
149 tbl->highest_used_slotid == NFS4_NO_SLOT)
150 tbl->highest_used_slotid = slotid;
151 slot->generation = tbl->generation;
152}
153
154/*
155 * nfs4_try_to_lock_slot - Given a slot try to allocate it
156 *
157 * Note: must be called with the slot_tbl_lock held.
158 */
159bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
160{
161 if (nfs4_test_locked_slot(tbl, slot->slot_nr))
162 return false;
163 nfs4_lock_slot(tbl, slot);
164 return true;
165}
166
167/*
168 * nfs4_lookup_slot - Find a slot but don't allocate it
169 *
170 * Note: must be called with the slot_tbl_lock held.
171 */
172struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid)
173{
174 if (slotid <= tbl->max_slotid)
175 return nfs4_find_or_create_slot(tbl, slotid, 0, GFP_NOWAIT);
176 return ERR_PTR(-E2BIG);
177}
178
179static int nfs4_slot_get_seqid(struct nfs4_slot_table *tbl, u32 slotid,
180 u32 *seq_nr)
181 __must_hold(&tbl->slot_tbl_lock)
182{
183 struct nfs4_slot *slot;
184 int ret;
185
186 slot = nfs4_lookup_slot(tbl, slotid);
187 ret = PTR_ERR_OR_ZERO(slot);
188 if (!ret)
189 *seq_nr = slot->seq_nr;
190
191 return ret;
192}
193
194/*
195 * nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
196 *
197 * Given a slot table, slot id and sequence number, determine if the
198 * RPC call in question is still in flight. This function is mainly
199 * intended for use by the callback channel.
200 */
201static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl,
202 u32 slotid, u32 seq_nr)
203{
204 u32 cur_seq = 0;
205 bool ret = false;
206
207 spin_lock(&tbl->slot_tbl_lock);
208 if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
209 cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
210 ret = true;
211 spin_unlock(&tbl->slot_tbl_lock);
212 return ret;
213}
214
215/*
216 * nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete
217 *
218 * Given a slot table, slot id and sequence number, wait until the
219 * corresponding RPC call completes. This function is mainly
220 * intended for use by the callback channel.
221 */
222int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
223 u32 slotid, u32 seq_nr,
224 unsigned long timeout)
225{
226 if (wait_event_timeout(tbl->slot_waitq,
227 !nfs4_slot_seqid_in_use(tbl, slotid, seq_nr),
228 timeout) == 0)
229 return -ETIMEDOUT;
230 return 0;
231}
232
233/*
234 * nfs4_alloc_slot - efficiently look for a free slot
235 *
236 * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
237 * If found, we mark the slot as used, update the highest_used_slotid,
238 * and respectively set up the sequence operation args.
239 *
240 * Note: must be called with under the slot_tbl_lock.
241 */
242struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
243{
244 struct nfs4_slot *ret = ERR_PTR(-EBUSY);
245 u32 slotid;
246
247 dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
248 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
249 tbl->max_slotid + 1);
250 slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
251 if (slotid <= tbl->max_slotid) {
252 ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
253 if (!IS_ERR(ret))
254 nfs4_lock_slot(tbl, ret);
255 }
256 dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
257 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
258 !IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
259 return ret;
260}
261
262static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
263 u32 max_reqs, u32 ivalue)
264{
265 if (max_reqs <= tbl->max_slots)
266 return 0;
267 if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
268 return 0;
269 return -ENOMEM;
270}
271
272static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
273 u32 server_highest_slotid,
274 u32 ivalue)
275{
276 struct nfs4_slot **p;
277
278 nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
279 p = &tbl->slots;
280 while (*p) {
281 (*p)->seq_nr = ivalue;
282 (*p)->seq_nr_highest_sent = ivalue;
283 (*p)->seq_nr_last_acked = ivalue - 1;
284 p = &(*p)->next;
285 }
286 tbl->highest_used_slotid = NFS4_NO_SLOT;
287 tbl->target_highest_slotid = server_highest_slotid;
288 tbl->server_highest_slotid = server_highest_slotid;
289 tbl->d_target_highest_slotid = 0;
290 tbl->d2_target_highest_slotid = 0;
291 tbl->max_slotid = server_highest_slotid;
292}
293
294/*
295 * (re)Initialise a slot table
296 */
297static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
298 u32 max_reqs, u32 ivalue)
299{
300 int ret;
301
302 dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
303 max_reqs, tbl->max_slots);
304
305 if (max_reqs > NFS4_MAX_SLOT_TABLE)
306 max_reqs = NFS4_MAX_SLOT_TABLE;
307
308 ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
309 if (ret)
310 goto out;
311
312 spin_lock(&tbl->slot_tbl_lock);
313 nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
314 spin_unlock(&tbl->slot_tbl_lock);
315
316 dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
317 tbl, tbl->slots, tbl->max_slots);
318out:
319 dprintk("<-- %s: return %d\n", __func__, ret);
320 return ret;
321}
322
323/*
324 * nfs4_release_slot_table - release all slot table entries
325 */
326static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
327{
328 nfs4_shrink_slot_table(tbl, 0);
329}
330
331/**
332 * nfs4_shutdown_slot_table - release resources attached to a slot table
333 * @tbl: slot table to shut down
334 *
335 */
336void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
337{
338 nfs4_release_slot_table(tbl);
339 rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
340}
341
342/**
343 * nfs4_setup_slot_table - prepare a stand-alone slot table for use
344 * @tbl: slot table to set up
345 * @max_reqs: maximum number of requests allowed
346 * @queue: name to give RPC wait queue
347 *
348 * Returns zero on success, or a negative errno.
349 */
350int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
351 const char *queue)
352{
353 nfs4_init_slot_table(tbl, queue);
354 return nfs4_realloc_slot_table(tbl, max_reqs, 0);
355}
356
357static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
358{
359 struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
360 struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
361 struct nfs4_slot *slot = pslot;
362 struct nfs4_slot_table *tbl = slot->table;
363
364 if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
365 return false;
366 slot->generation = tbl->generation;
367 args->sa_slot = slot;
368 res->sr_timestamp = jiffies;
369 res->sr_slot = slot;
370 res->sr_status_flags = 0;
371 res->sr_status = 1;
372 return true;
373}
374
375static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
376 struct nfs4_slot *slot)
377{
378 if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
379 return true;
380 return false;
381}
382
383bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
384 struct nfs4_slot *slot)
385{
386 if (slot->slot_nr > tbl->max_slotid)
387 return false;
388 return __nfs41_wake_and_assign_slot(tbl, slot);
389}
390
391static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
392{
393 struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
394 if (!IS_ERR(slot)) {
395 bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
396 if (ret)
397 return ret;
398 nfs4_free_slot(tbl, slot);
399 }
400 return false;
401}
402
403void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
404{
405 for (;;) {
406 if (!nfs41_try_wake_next_slot_table_entry(tbl))
407 break;
408 }
409}
410
411#if defined(CONFIG_NFS_V4_1)
412
413static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
414 u32 target_highest_slotid)
415{
416 u32 max_slotid;
417
418 max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
419 if (max_slotid > tbl->server_highest_slotid)
420 max_slotid = tbl->server_highest_slotid;
421 if (max_slotid > tbl->target_highest_slotid)
422 max_slotid = tbl->target_highest_slotid;
423 tbl->max_slotid = max_slotid;
424 nfs41_wake_slot_table(tbl);
425}
426
427/* Update the client's idea of target_highest_slotid */
428static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
429 u32 target_highest_slotid)
430{
431 if (tbl->target_highest_slotid == target_highest_slotid)
432 return;
433 tbl->target_highest_slotid = target_highest_slotid;
434 tbl->generation++;
435}
436
437void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
438 u32 target_highest_slotid)
439{
440 spin_lock(&tbl->slot_tbl_lock);
441 nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
442 tbl->d_target_highest_slotid = 0;
443 tbl->d2_target_highest_slotid = 0;
444 nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
445 spin_unlock(&tbl->slot_tbl_lock);
446}
447
448static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
449 u32 highest_slotid)
450{
451 if (tbl->server_highest_slotid == highest_slotid)
452 return;
453 if (tbl->highest_used_slotid > highest_slotid)
454 return;
455 /* Deallocate slots */
456 nfs4_shrink_slot_table(tbl, highest_slotid + 1);
457 tbl->server_highest_slotid = highest_slotid;
458}
459
460static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
461{
462 s1 -= s2;
463 if (s1 == 0)
464 return 0;
465 if (s1 < 0)
466 return (s1 - 1) >> 1;
467 return (s1 + 1) >> 1;
468}
469
470static int nfs41_sign_s32(s32 s1)
471{
472 if (s1 > 0)
473 return 1;
474 if (s1 < 0)
475 return -1;
476 return 0;
477}
478
479static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
480{
481 if (!s1 || !s2)
482 return true;
483 return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
484}
485
486/* Try to eliminate outliers by checking for sharp changes in the
487 * derivatives and second derivatives
488 */
489static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
490 u32 new_target)
491{
492 s32 d_target, d2_target;
493 bool ret = true;
494
495 d_target = nfs41_derivative_target_slotid(new_target,
496 tbl->target_highest_slotid);
497 d2_target = nfs41_derivative_target_slotid(d_target,
498 tbl->d_target_highest_slotid);
499 /* Is first derivative same sign? */
500 if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
501 ret = false;
502 /* Is second derivative same sign? */
503 if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
504 ret = false;
505 tbl->d_target_highest_slotid = d_target;
506 tbl->d2_target_highest_slotid = d2_target;
507 return ret;
508}
509
510void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
511 struct nfs4_slot *slot,
512 struct nfs4_sequence_res *res)
513{
514 spin_lock(&tbl->slot_tbl_lock);
515 if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
516 nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
517 if (tbl->generation == slot->generation)
518 nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
519 nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
520 spin_unlock(&tbl->slot_tbl_lock);
521}
522
523static void nfs4_release_session_slot_tables(struct nfs4_session *session)
524{
525 nfs4_release_slot_table(&session->fc_slot_table);
526 nfs4_release_slot_table(&session->bc_slot_table);
527}
528
529/*
530 * Initialize or reset the forechannel and backchannel tables
531 */
532int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
533{
534 struct nfs4_slot_table *tbl;
535 int status;
536
537 dprintk("--> %s\n", __func__);
538 /* Fore channel */
539 tbl = &ses->fc_slot_table;
540 tbl->session = ses;
541 status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
542 if (status || !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */
543 return status;
544 /* Back channel */
545 tbl = &ses->bc_slot_table;
546 tbl->session = ses;
547 status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
548 if (status && tbl->slots == NULL)
549 /* Fore and back channel share a connection so get
550 * both slot tables or neither */
551 nfs4_release_session_slot_tables(ses);
552 return status;
553}
554
555struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
556{
557 struct nfs4_session *session;
558
559 session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
560 if (!session)
561 return NULL;
562
563 nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
564 nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
565 session->session_state = 1<<NFS4_SESSION_INITING;
566
567 session->clp = clp;
568 return session;
569}
570
571static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
572{
573 nfs4_shutdown_slot_table(&session->fc_slot_table);
574 nfs4_shutdown_slot_table(&session->bc_slot_table);
575}
576
577void nfs4_destroy_session(struct nfs4_session *session)
578{
579 struct rpc_xprt *xprt;
580 const struct cred *cred;
581
582 cred = nfs4_get_clid_cred(session->clp);
583 nfs4_proc_destroy_session(session, cred);
584 put_cred(cred);
585
586 rcu_read_lock();
587 xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
588 rcu_read_unlock();
589 dprintk("%s Destroy backchannel for xprt %p\n",
590 __func__, xprt);
591 xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
592 nfs4_destroy_session_slot_tables(session);
593 kfree(session);
594}
595
596/*
597 * With sessions, the client is not marked ready until after a
598 * successful EXCHANGE_ID and CREATE_SESSION.
599 *
600 * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
601 * other versions of NFS can be tried.
602 */
603static int nfs41_check_session_ready(struct nfs_client *clp)
604{
605 int ret;
606
607 if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
608 ret = nfs4_client_recover_expired_lease(clp);
609 if (ret)
610 return ret;
611 }
612 if (clp->cl_cons_state < NFS_CS_READY)
613 return -EPROTONOSUPPORT;
614 smp_rmb();
615 return 0;
616}
617
618int nfs4_init_session(struct nfs_client *clp)
619{
620 if (!nfs4_has_session(clp))
621 return 0;
622
623 clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
624 return nfs41_check_session_ready(clp);
625}
626
627int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
628{
629 struct nfs4_session *session = clp->cl_session;
630 int ret;
631
632 spin_lock(&clp->cl_lock);
633 if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
634 /*
635 * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
636 * DS lease to be equal to the MDS lease.
637 */
638 clp->cl_lease_time = lease_time;
639 clp->cl_last_renewal = jiffies;
640 }
641 spin_unlock(&clp->cl_lock);
642
643 ret = nfs41_check_session_ready(clp);
644 if (ret)
645 return ret;
646 /* Test for the DS role */
647 if (!is_ds_client(clp))
648 return -ENODEV;
649 return 0;
650}
651EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
652
653#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
138static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
139 struct nfs4_slot *slot)
140{
141 u32 slotid = slot->slot_nr;
142
143 __set_bit(slotid, tbl->used_slots);
144 if (slotid > tbl->highest_used_slotid ||
145 tbl->highest_used_slotid == NFS4_NO_SLOT)
146 tbl->highest_used_slotid = slotid;
147 slot->generation = tbl->generation;
148}
149
150/*
151 * nfs4_try_to_lock_slot - Given a slot try to allocate it
152 *
153 * Note: must be called with the slot_tbl_lock held.
154 */
155bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
156{
157 if (nfs4_test_locked_slot(tbl, slot->slot_nr))
158 return false;
159 nfs4_lock_slot(tbl, slot);
160 return true;
161}
162
163/*
164 * nfs4_lookup_slot - Find a slot but don't allocate it
165 *
166 * Note: must be called with the slot_tbl_lock held.
167 */
168struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid)
169{
170 if (slotid <= tbl->max_slotid)
171 return nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
172 return ERR_PTR(-E2BIG);
173}
174
175/*
176 * nfs4_alloc_slot - efficiently look for a free slot
177 *
178 * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
179 * If found, we mark the slot as used, update the highest_used_slotid,
180 * and respectively set up the sequence operation args.
181 *
182 * Note: must be called with under the slot_tbl_lock.
183 */
184struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
185{
186 struct nfs4_slot *ret = ERR_PTR(-EBUSY);
187 u32 slotid;
188
189 dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
190 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
191 tbl->max_slotid + 1);
192 slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
193 if (slotid <= tbl->max_slotid) {
194 ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
195 if (!IS_ERR(ret))
196 nfs4_lock_slot(tbl, ret);
197 }
198 dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
199 __func__, tbl->used_slots[0], tbl->highest_used_slotid,
200 !IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
201 return ret;
202}
203
204static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
205 u32 max_reqs, u32 ivalue)
206{
207 if (max_reqs <= tbl->max_slots)
208 return 0;
209 if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
210 return 0;
211 return -ENOMEM;
212}
213
214static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
215 u32 server_highest_slotid,
216 u32 ivalue)
217{
218 struct nfs4_slot **p;
219
220 nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
221 p = &tbl->slots;
222 while (*p) {
223 (*p)->seq_nr = ivalue;
224 (*p)->interrupted = 0;
225 p = &(*p)->next;
226 }
227 tbl->highest_used_slotid = NFS4_NO_SLOT;
228 tbl->target_highest_slotid = server_highest_slotid;
229 tbl->server_highest_slotid = server_highest_slotid;
230 tbl->d_target_highest_slotid = 0;
231 tbl->d2_target_highest_slotid = 0;
232 tbl->max_slotid = server_highest_slotid;
233}
234
235/*
236 * (re)Initialise a slot table
237 */
238static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
239 u32 max_reqs, u32 ivalue)
240{
241 int ret;
242
243 dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
244 max_reqs, tbl->max_slots);
245
246 if (max_reqs > NFS4_MAX_SLOT_TABLE)
247 max_reqs = NFS4_MAX_SLOT_TABLE;
248
249 ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
250 if (ret)
251 goto out;
252
253 spin_lock(&tbl->slot_tbl_lock);
254 nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
255 spin_unlock(&tbl->slot_tbl_lock);
256
257 dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
258 tbl, tbl->slots, tbl->max_slots);
259out:
260 dprintk("<-- %s: return %d\n", __func__, ret);
261 return ret;
262}
263
264/*
265 * nfs4_release_slot_table - release all slot table entries
266 */
267static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
268{
269 nfs4_shrink_slot_table(tbl, 0);
270}
271
272/**
273 * nfs4_shutdown_slot_table - release resources attached to a slot table
274 * @tbl: slot table to shut down
275 *
276 */
277void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
278{
279 nfs4_release_slot_table(tbl);
280 rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
281}
282
283/**
284 * nfs4_setup_slot_table - prepare a stand-alone slot table for use
285 * @tbl: slot table to set up
286 * @max_reqs: maximum number of requests allowed
287 * @queue: name to give RPC wait queue
288 *
289 * Returns zero on success, or a negative errno.
290 */
291int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
292 const char *queue)
293{
294 nfs4_init_slot_table(tbl, queue);
295 return nfs4_realloc_slot_table(tbl, max_reqs, 0);
296}
297
298static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
299{
300 struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
301 struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
302 struct nfs4_slot *slot = pslot;
303 struct nfs4_slot_table *tbl = slot->table;
304
305 if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
306 return false;
307 slot->generation = tbl->generation;
308 args->sa_slot = slot;
309 res->sr_timestamp = jiffies;
310 res->sr_slot = slot;
311 res->sr_status_flags = 0;
312 res->sr_status = 1;
313 return true;
314}
315
316static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
317 struct nfs4_slot *slot)
318{
319 if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
320 return true;
321 return false;
322}
323
324bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
325 struct nfs4_slot *slot)
326{
327 if (slot->slot_nr > tbl->max_slotid)
328 return false;
329 return __nfs41_wake_and_assign_slot(tbl, slot);
330}
331
332static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
333{
334 struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
335 if (!IS_ERR(slot)) {
336 bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
337 if (ret)
338 return ret;
339 nfs4_free_slot(tbl, slot);
340 }
341 return false;
342}
343
344void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
345{
346 for (;;) {
347 if (!nfs41_try_wake_next_slot_table_entry(tbl))
348 break;
349 }
350}
351
352#if defined(CONFIG_NFS_V4_1)
353
354static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
355 u32 target_highest_slotid)
356{
357 u32 max_slotid;
358
359 max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
360 if (max_slotid > tbl->server_highest_slotid)
361 max_slotid = tbl->server_highest_slotid;
362 if (max_slotid > tbl->target_highest_slotid)
363 max_slotid = tbl->target_highest_slotid;
364 tbl->max_slotid = max_slotid;
365 nfs41_wake_slot_table(tbl);
366}
367
368/* Update the client's idea of target_highest_slotid */
369static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
370 u32 target_highest_slotid)
371{
372 if (tbl->target_highest_slotid == target_highest_slotid)
373 return;
374 tbl->target_highest_slotid = target_highest_slotid;
375 tbl->generation++;
376}
377
378void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
379 u32 target_highest_slotid)
380{
381 spin_lock(&tbl->slot_tbl_lock);
382 nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
383 tbl->d_target_highest_slotid = 0;
384 tbl->d2_target_highest_slotid = 0;
385 nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
386 spin_unlock(&tbl->slot_tbl_lock);
387}
388
389static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
390 u32 highest_slotid)
391{
392 if (tbl->server_highest_slotid == highest_slotid)
393 return;
394 if (tbl->highest_used_slotid > highest_slotid)
395 return;
396 /* Deallocate slots */
397 nfs4_shrink_slot_table(tbl, highest_slotid + 1);
398 tbl->server_highest_slotid = highest_slotid;
399}
400
401static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
402{
403 s1 -= s2;
404 if (s1 == 0)
405 return 0;
406 if (s1 < 0)
407 return (s1 - 1) >> 1;
408 return (s1 + 1) >> 1;
409}
410
411static int nfs41_sign_s32(s32 s1)
412{
413 if (s1 > 0)
414 return 1;
415 if (s1 < 0)
416 return -1;
417 return 0;
418}
419
420static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
421{
422 if (!s1 || !s2)
423 return true;
424 return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
425}
426
427/* Try to eliminate outliers by checking for sharp changes in the
428 * derivatives and second derivatives
429 */
430static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
431 u32 new_target)
432{
433 s32 d_target, d2_target;
434 bool ret = true;
435
436 d_target = nfs41_derivative_target_slotid(new_target,
437 tbl->target_highest_slotid);
438 d2_target = nfs41_derivative_target_slotid(d_target,
439 tbl->d_target_highest_slotid);
440 /* Is first derivative same sign? */
441 if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
442 ret = false;
443 /* Is second derivative same sign? */
444 if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
445 ret = false;
446 tbl->d_target_highest_slotid = d_target;
447 tbl->d2_target_highest_slotid = d2_target;
448 return ret;
449}
450
451void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
452 struct nfs4_slot *slot,
453 struct nfs4_sequence_res *res)
454{
455 spin_lock(&tbl->slot_tbl_lock);
456 if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
457 nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
458 if (tbl->generation == slot->generation)
459 nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
460 nfs41_set_max_slotid_locked(tbl, res->sr_target_highest_slotid);
461 spin_unlock(&tbl->slot_tbl_lock);
462}
463
464static void nfs4_release_session_slot_tables(struct nfs4_session *session)
465{
466 nfs4_release_slot_table(&session->fc_slot_table);
467 nfs4_release_slot_table(&session->bc_slot_table);
468}
469
470/*
471 * Initialize or reset the forechannel and backchannel tables
472 */
473int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
474{
475 struct nfs4_slot_table *tbl;
476 int status;
477
478 dprintk("--> %s\n", __func__);
479 /* Fore channel */
480 tbl = &ses->fc_slot_table;
481 tbl->session = ses;
482 status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
483 if (status || !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */
484 return status;
485 /* Back channel */
486 tbl = &ses->bc_slot_table;
487 tbl->session = ses;
488 status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
489 if (status && tbl->slots == NULL)
490 /* Fore and back channel share a connection so get
491 * both slot tables or neither */
492 nfs4_release_session_slot_tables(ses);
493 return status;
494}
495
496struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
497{
498 struct nfs4_session *session;
499
500 session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
501 if (!session)
502 return NULL;
503
504 nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
505 nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
506 session->session_state = 1<<NFS4_SESSION_INITING;
507
508 session->clp = clp;
509 return session;
510}
511
512static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
513{
514 nfs4_shutdown_slot_table(&session->fc_slot_table);
515 nfs4_shutdown_slot_table(&session->bc_slot_table);
516}
517
518void nfs4_destroy_session(struct nfs4_session *session)
519{
520 struct rpc_xprt *xprt;
521 struct rpc_cred *cred;
522
523 cred = nfs4_get_clid_cred(session->clp);
524 nfs4_proc_destroy_session(session, cred);
525 if (cred)
526 put_rpccred(cred);
527
528 rcu_read_lock();
529 xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
530 rcu_read_unlock();
531 dprintk("%s Destroy backchannel for xprt %p\n",
532 __func__, xprt);
533 xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
534 nfs4_destroy_session_slot_tables(session);
535 kfree(session);
536}
537
538/*
539 * With sessions, the client is not marked ready until after a
540 * successful EXCHANGE_ID and CREATE_SESSION.
541 *
542 * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
543 * other versions of NFS can be tried.
544 */
545static int nfs41_check_session_ready(struct nfs_client *clp)
546{
547 int ret;
548
549 if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
550 ret = nfs4_client_recover_expired_lease(clp);
551 if (ret)
552 return ret;
553 }
554 if (clp->cl_cons_state < NFS_CS_READY)
555 return -EPROTONOSUPPORT;
556 smp_rmb();
557 return 0;
558}
559
560int nfs4_init_session(struct nfs_client *clp)
561{
562 if (!nfs4_has_session(clp))
563 return 0;
564
565 clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
566 return nfs41_check_session_ready(clp);
567}
568
569int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
570{
571 struct nfs4_session *session = clp->cl_session;
572 int ret;
573
574 spin_lock(&clp->cl_lock);
575 if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
576 /*
577 * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
578 * DS lease to be equal to the MDS lease.
579 */
580 clp->cl_lease_time = lease_time;
581 clp->cl_last_renewal = jiffies;
582 }
583 spin_unlock(&clp->cl_lock);
584
585 ret = nfs41_check_session_ready(clp);
586 if (ret)
587 return ret;
588 /* Test for the DS role */
589 if (!is_ds_client(clp))
590 return -ENODEV;
591 return 0;
592}
593EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
594
595#endif /* defined(CONFIG_NFS_V4_1) */