fb: adv7393: off by one in probe function
[deliverable/linux.git] / fs / nfs / nfs4session.c
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
26 static 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 */
37 static 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 */
60 void 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 */
81 void 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
102 static 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
116 static 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 static 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 */
155 bool 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 */
168 struct 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 */
184 struct 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
204 static 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
214 static 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 */
238 static 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);
259 out:
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 */
267 static 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 */
277 void 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 */
291 int 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
298 static 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
316 static 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
324 bool 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
332 static 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
344 void 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
354 static 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 */
369 static 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
378 void 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
389 static 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
401 static 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
411 static 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
420 static 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 */
430 static 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
451 void 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
464 static 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 */
473 int 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
496 struct 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
512 static 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
518 void 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 */
545 static 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
560 int 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
569 int 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 }
593 EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
594
595 #endif /* defined(CONFIG_NFS_V4_1) */
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