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 
nfs4_init_slot_table(struct nfs4_slot_table * tbl,const char * queue)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_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  */
nfs4_shrink_slot_table(struct nfs4_slot_table * tbl,u32 newsize)38 static 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  */
nfs4_slot_tbl_drain_complete(struct nfs4_slot_table * tbl)61 void 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  */
nfs4_free_slot(struct nfs4_slot_table * tbl,struct nfs4_slot * slot)82 void 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 
nfs4_new_slot(struct nfs4_slot_table * tbl,u32 slotid,u32 seq_init,gfp_t gfp_mask)103 static 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 
nfs4_find_or_create_slot(struct nfs4_slot_table * tbl,u32 slotid,u32 seq_init,gfp_t gfp_mask)117 static 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 
nfs4_lock_slot(struct nfs4_slot_table * tbl,struct nfs4_slot * slot)139 static 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  */
nfs4_try_to_lock_slot(struct nfs4_slot_table * tbl,struct nfs4_slot * slot)156 bool 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  */
nfs4_lookup_slot(struct nfs4_slot_table * tbl,u32 slotid)169 struct 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 
nfs4_slot_get_seqid(struct nfs4_slot_table * tbl,u32 slotid,u32 * seq_nr)176 static 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  */
nfs4_slot_seqid_in_use(struct nfs4_slot_table * tbl,u32 slotid,u32 seq_nr)198 static 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  */
nfs4_slot_wait_on_seqid(struct nfs4_slot_table * tbl,u32 slotid,u32 seq_nr,unsigned long timeout)219 int 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  */
nfs4_alloc_slot(struct nfs4_slot_table * tbl)239 struct 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 
nfs4_grow_slot_table(struct nfs4_slot_table * tbl,u32 max_reqs,u32 ivalue)259 static 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 
nfs4_reset_slot_table(struct nfs4_slot_table * tbl,u32 server_highest_slotid,u32 ivalue)269 static 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  */
nfs4_realloc_slot_table(struct nfs4_slot_table * tbl,u32 max_reqs,u32 ivalue)293 static 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);
314 out:
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  */
nfs4_release_slot_table(struct nfs4_slot_table * tbl)322 static 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  */
nfs4_shutdown_slot_table(struct nfs4_slot_table * tbl)332 void 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  */
nfs4_setup_slot_table(struct nfs4_slot_table * tbl,unsigned int max_reqs,const char * queue)346 int 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 
nfs41_assign_slot(struct rpc_task * task,void * pslot)353 static 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 
__nfs41_wake_and_assign_slot(struct nfs4_slot_table * tbl,struct nfs4_slot * slot)371 static 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 
nfs41_wake_and_assign_slot(struct nfs4_slot_table * tbl,struct nfs4_slot * slot)379 bool 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 
nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table * tbl)387 static 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 
nfs41_wake_slot_table(struct nfs4_slot_table * tbl)399 void 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 
nfs41_set_max_slotid_locked(struct nfs4_slot_table * tbl,u32 target_highest_slotid)409 static 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 */
nfs41_set_target_slotid_locked(struct nfs4_slot_table * tbl,u32 target_highest_slotid)424 static 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 
nfs41_set_target_slotid(struct nfs4_slot_table * tbl,u32 target_highest_slotid)433 void 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 
nfs41_set_server_slotid_locked(struct nfs4_slot_table * tbl,u32 highest_slotid)444 static 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 
nfs41_derivative_target_slotid(s32 s1,s32 s2)456 static 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 
nfs41_sign_s32(s32 s1)466 static 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 
nfs41_same_sign_or_zero_s32(s32 s1,s32 s2)475 static 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  */
nfs41_is_outlier_target_slotid(struct nfs4_slot_table * tbl,u32 new_target)485 static 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 
nfs41_update_target_slotid(struct nfs4_slot_table * tbl,struct nfs4_slot * slot,struct nfs4_sequence_res * res)506 void 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 
nfs4_release_session_slot_tables(struct nfs4_session * session)519 static 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  */
nfs4_setup_session_slot_tables(struct nfs4_session * ses)528 int 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 
nfs4_alloc_session(struct nfs_client * clp)551 struct 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 
nfs4_destroy_session_slot_tables(struct nfs4_session * session)567 static 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 
nfs4_destroy_session(struct nfs4_session * session)573 void 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  */
nfs41_check_session_ready(struct nfs_client * clp)600 static 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 
nfs4_init_session(struct nfs_client * clp)615 int 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 
nfs4_init_ds_session(struct nfs_client * clp,unsigned long lease_time)624 int 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 }
648 EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
649 
650 #endif	/* defined(CONFIG_NFS_V4_1) */
651