xref: /linux/fs/nfs/callback_proc.c (revision 96ac6d435100450f0565708d9b885ea2a7400e0a)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/fs/nfs/callback_proc.c
4  *
5  * Copyright (C) 2004 Trond Myklebust
6  *
7  * NFSv4 callback procedures
8  */
9 #include <linux/nfs4.h>
10 #include <linux/nfs_fs.h>
11 #include <linux/slab.h>
12 #include <linux/rcupdate.h>
13 #include "nfs4_fs.h"
14 #include "callback.h"
15 #include "delegation.h"
16 #include "internal.h"
17 #include "pnfs.h"
18 #include "nfs4session.h"
19 #include "nfs4trace.h"
20 
21 #define NFSDBG_FACILITY NFSDBG_CALLBACK
22 
23 __be32 nfs4_callback_getattr(void *argp, void *resp,
24 			     struct cb_process_state *cps)
25 {
26 	struct cb_getattrargs *args = argp;
27 	struct cb_getattrres *res = resp;
28 	struct nfs_delegation *delegation;
29 	struct nfs_inode *nfsi;
30 	struct inode *inode;
31 
32 	res->status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
33 	if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
34 		goto out;
35 
36 	res->bitmap[0] = res->bitmap[1] = 0;
37 	res->status = htonl(NFS4ERR_BADHANDLE);
38 
39 	dprintk_rcu("NFS: GETATTR callback request from %s\n",
40 		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
41 
42 	inode = nfs_delegation_find_inode(cps->clp, &args->fh);
43 	if (IS_ERR(inode)) {
44 		if (inode == ERR_PTR(-EAGAIN))
45 			res->status = htonl(NFS4ERR_DELAY);
46 		trace_nfs4_cb_getattr(cps->clp, &args->fh, NULL,
47 				-ntohl(res->status));
48 		goto out;
49 	}
50 	nfsi = NFS_I(inode);
51 	rcu_read_lock();
52 	delegation = rcu_dereference(nfsi->delegation);
53 	if (delegation == NULL || (delegation->type & FMODE_WRITE) == 0)
54 		goto out_iput;
55 	res->size = i_size_read(inode);
56 	res->change_attr = delegation->change_attr;
57 	if (nfs_have_writebacks(inode))
58 		res->change_attr++;
59 	res->ctime = timespec64_to_timespec(inode->i_ctime);
60 	res->mtime = timespec64_to_timespec(inode->i_mtime);
61 	res->bitmap[0] = (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE) &
62 		args->bitmap[0];
63 	res->bitmap[1] = (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY) &
64 		args->bitmap[1];
65 	res->status = 0;
66 out_iput:
67 	rcu_read_unlock();
68 	trace_nfs4_cb_getattr(cps->clp, &args->fh, inode, -ntohl(res->status));
69 	nfs_iput_and_deactive(inode);
70 out:
71 	dprintk("%s: exit with status = %d\n", __func__, ntohl(res->status));
72 	return res->status;
73 }
74 
75 __be32 nfs4_callback_recall(void *argp, void *resp,
76 			    struct cb_process_state *cps)
77 {
78 	struct cb_recallargs *args = argp;
79 	struct inode *inode;
80 	__be32 res;
81 
82 	res = htonl(NFS4ERR_OP_NOT_IN_SESSION);
83 	if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
84 		goto out;
85 
86 	dprintk_rcu("NFS: RECALL callback request from %s\n",
87 		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
88 
89 	res = htonl(NFS4ERR_BADHANDLE);
90 	inode = nfs_delegation_find_inode(cps->clp, &args->fh);
91 	if (IS_ERR(inode)) {
92 		if (inode == ERR_PTR(-EAGAIN))
93 			res = htonl(NFS4ERR_DELAY);
94 		trace_nfs4_cb_recall(cps->clp, &args->fh, NULL,
95 				&args->stateid, -ntohl(res));
96 		goto out;
97 	}
98 	/* Set up a helper thread to actually return the delegation */
99 	switch (nfs_async_inode_return_delegation(inode, &args->stateid)) {
100 	case 0:
101 		res = 0;
102 		break;
103 	case -ENOENT:
104 		res = htonl(NFS4ERR_BAD_STATEID);
105 		break;
106 	default:
107 		res = htonl(NFS4ERR_RESOURCE);
108 	}
109 	trace_nfs4_cb_recall(cps->clp, &args->fh, inode,
110 			&args->stateid, -ntohl(res));
111 	nfs_iput_and_deactive(inode);
112 out:
113 	dprintk("%s: exit with status = %d\n", __func__, ntohl(res));
114 	return res;
115 }
116 
117 #if defined(CONFIG_NFS_V4_1)
118 
119 /*
120  * Lookup a layout inode by stateid
121  *
122  * Note: returns a refcount on the inode and superblock
123  */
124 static struct inode *nfs_layout_find_inode_by_stateid(struct nfs_client *clp,
125 		const nfs4_stateid *stateid)
126 {
127 	struct nfs_server *server;
128 	struct inode *inode;
129 	struct pnfs_layout_hdr *lo;
130 
131 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
132 		list_for_each_entry(lo, &server->layouts, plh_layouts) {
133 			if (stateid != NULL &&
134 			    !nfs4_stateid_match_other(stateid, &lo->plh_stateid))
135 				continue;
136 			inode = igrab(lo->plh_inode);
137 			if (!inode)
138 				return ERR_PTR(-EAGAIN);
139 			if (!nfs_sb_active(inode->i_sb)) {
140 				rcu_read_unlock();
141 				spin_unlock(&clp->cl_lock);
142 				iput(inode);
143 				spin_lock(&clp->cl_lock);
144 				rcu_read_lock();
145 				return ERR_PTR(-EAGAIN);
146 			}
147 			return inode;
148 		}
149 	}
150 
151 	return ERR_PTR(-ENOENT);
152 }
153 
154 /*
155  * Lookup a layout inode by filehandle.
156  *
157  * Note: returns a refcount on the inode and superblock
158  *
159  */
160 static struct inode *nfs_layout_find_inode_by_fh(struct nfs_client *clp,
161 		const struct nfs_fh *fh)
162 {
163 	struct nfs_server *server;
164 	struct nfs_inode *nfsi;
165 	struct inode *inode;
166 	struct pnfs_layout_hdr *lo;
167 
168 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
169 		list_for_each_entry(lo, &server->layouts, plh_layouts) {
170 			nfsi = NFS_I(lo->plh_inode);
171 			if (nfs_compare_fh(fh, &nfsi->fh))
172 				continue;
173 			if (nfsi->layout != lo)
174 				continue;
175 			inode = igrab(lo->plh_inode);
176 			if (!inode)
177 				return ERR_PTR(-EAGAIN);
178 			if (!nfs_sb_active(inode->i_sb)) {
179 				rcu_read_unlock();
180 				spin_unlock(&clp->cl_lock);
181 				iput(inode);
182 				spin_lock(&clp->cl_lock);
183 				rcu_read_lock();
184 				return ERR_PTR(-EAGAIN);
185 			}
186 			return inode;
187 		}
188 	}
189 
190 	return ERR_PTR(-ENOENT);
191 }
192 
193 static struct inode *nfs_layout_find_inode(struct nfs_client *clp,
194 		const struct nfs_fh *fh,
195 		const nfs4_stateid *stateid)
196 {
197 	struct inode *inode;
198 
199 	spin_lock(&clp->cl_lock);
200 	rcu_read_lock();
201 	inode = nfs_layout_find_inode_by_stateid(clp, stateid);
202 	if (inode == ERR_PTR(-ENOENT))
203 		inode = nfs_layout_find_inode_by_fh(clp, fh);
204 	rcu_read_unlock();
205 	spin_unlock(&clp->cl_lock);
206 
207 	return inode;
208 }
209 
210 /*
211  * Enforce RFC5661 section 12.5.5.2.1. (Layout Recall and Return Sequencing)
212  */
213 static u32 pnfs_check_callback_stateid(struct pnfs_layout_hdr *lo,
214 					const nfs4_stateid *new)
215 {
216 	u32 oldseq, newseq;
217 
218 	/* Is the stateid not initialised? */
219 	if (!pnfs_layout_is_valid(lo))
220 		return NFS4ERR_NOMATCHING_LAYOUT;
221 
222 	/* Mismatched stateid? */
223 	if (!nfs4_stateid_match_other(&lo->plh_stateid, new))
224 		return NFS4ERR_BAD_STATEID;
225 
226 	newseq = be32_to_cpu(new->seqid);
227 	/* Are we already in a layout recall situation? */
228 	if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags) &&
229 	    lo->plh_return_seq != 0) {
230 		if (newseq < lo->plh_return_seq)
231 			return NFS4ERR_OLD_STATEID;
232 		if (newseq > lo->plh_return_seq)
233 			return NFS4ERR_DELAY;
234 		goto out;
235 	}
236 
237 	/* Check that the stateid matches what we think it should be. */
238 	oldseq = be32_to_cpu(lo->plh_stateid.seqid);
239 	if (newseq > oldseq + 1)
240 		return NFS4ERR_DELAY;
241 	/* Crazy server! */
242 	if (newseq <= oldseq)
243 		return NFS4ERR_OLD_STATEID;
244 out:
245 	return NFS_OK;
246 }
247 
248 static u32 initiate_file_draining(struct nfs_client *clp,
249 				  struct cb_layoutrecallargs *args)
250 {
251 	struct inode *ino;
252 	struct pnfs_layout_hdr *lo;
253 	u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
254 	LIST_HEAD(free_me_list);
255 
256 	ino = nfs_layout_find_inode(clp, &args->cbl_fh, &args->cbl_stateid);
257 	if (IS_ERR(ino)) {
258 		if (ino == ERR_PTR(-EAGAIN))
259 			rv = NFS4ERR_DELAY;
260 		goto out_noput;
261 	}
262 
263 	pnfs_layoutcommit_inode(ino, false);
264 
265 
266 	spin_lock(&ino->i_lock);
267 	lo = NFS_I(ino)->layout;
268 	if (!lo) {
269 		spin_unlock(&ino->i_lock);
270 		goto out;
271 	}
272 	pnfs_get_layout_hdr(lo);
273 	rv = pnfs_check_callback_stateid(lo, &args->cbl_stateid);
274 	if (rv != NFS_OK)
275 		goto unlock;
276 
277 	/*
278 	 * Enforce RFC5661 Section 12.5.5.2.1.5 (Bulk Recall and Return)
279 	 */
280 	if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
281 		rv = NFS4ERR_DELAY;
282 		goto unlock;
283 	}
284 
285 	pnfs_set_layout_stateid(lo, &args->cbl_stateid, true);
286 	switch (pnfs_mark_matching_lsegs_return(lo, &free_me_list,
287 				&args->cbl_range,
288 				be32_to_cpu(args->cbl_stateid.seqid))) {
289 	case 0:
290 	case -EBUSY:
291 		/* There are layout segments that need to be returned */
292 		rv = NFS4_OK;
293 		break;
294 	case -ENOENT:
295 		/* Embrace your forgetfulness! */
296 		rv = NFS4ERR_NOMATCHING_LAYOUT;
297 
298 		if (NFS_SERVER(ino)->pnfs_curr_ld->return_range) {
299 			NFS_SERVER(ino)->pnfs_curr_ld->return_range(lo,
300 				&args->cbl_range);
301 		}
302 	}
303 unlock:
304 	spin_unlock(&ino->i_lock);
305 	pnfs_free_lseg_list(&free_me_list);
306 	/* Free all lsegs that are attached to commit buckets */
307 	nfs_commit_inode(ino, 0);
308 	pnfs_put_layout_hdr(lo);
309 out:
310 	nfs_iput_and_deactive(ino);
311 out_noput:
312 	trace_nfs4_cb_layoutrecall_file(clp, &args->cbl_fh, ino,
313 			&args->cbl_stateid, -rv);
314 	return rv;
315 }
316 
317 static u32 initiate_bulk_draining(struct nfs_client *clp,
318 				  struct cb_layoutrecallargs *args)
319 {
320 	int stat;
321 
322 	if (args->cbl_recall_type == RETURN_FSID)
323 		stat = pnfs_destroy_layouts_byfsid(clp, &args->cbl_fsid, true);
324 	else
325 		stat = pnfs_destroy_layouts_byclid(clp, true);
326 	if (stat != 0)
327 		return NFS4ERR_DELAY;
328 	return NFS4ERR_NOMATCHING_LAYOUT;
329 }
330 
331 static u32 do_callback_layoutrecall(struct nfs_client *clp,
332 				    struct cb_layoutrecallargs *args)
333 {
334 	if (args->cbl_recall_type == RETURN_FILE)
335 		return initiate_file_draining(clp, args);
336 	return initiate_bulk_draining(clp, args);
337 }
338 
339 __be32 nfs4_callback_layoutrecall(void *argp, void *resp,
340 				  struct cb_process_state *cps)
341 {
342 	struct cb_layoutrecallargs *args = argp;
343 	u32 res = NFS4ERR_OP_NOT_IN_SESSION;
344 
345 	if (cps->clp)
346 		res = do_callback_layoutrecall(cps->clp, args);
347 	return cpu_to_be32(res);
348 }
349 
350 static void pnfs_recall_all_layouts(struct nfs_client *clp)
351 {
352 	struct cb_layoutrecallargs args;
353 
354 	/* Pretend we got a CB_LAYOUTRECALL(ALL) */
355 	memset(&args, 0, sizeof(args));
356 	args.cbl_recall_type = RETURN_ALL;
357 	/* FIXME we ignore errors, what should we do? */
358 	do_callback_layoutrecall(clp, &args);
359 }
360 
361 __be32 nfs4_callback_devicenotify(void *argp, void *resp,
362 				  struct cb_process_state *cps)
363 {
364 	struct cb_devicenotifyargs *args = argp;
365 	int i;
366 	__be32 res = 0;
367 	struct nfs_client *clp = cps->clp;
368 	struct nfs_server *server = NULL;
369 
370 	if (!clp) {
371 		res = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
372 		goto out;
373 	}
374 
375 	for (i = 0; i < args->ndevs; i++) {
376 		struct cb_devicenotifyitem *dev = &args->devs[i];
377 
378 		if (!server ||
379 		    server->pnfs_curr_ld->id != dev->cbd_layout_type) {
380 			rcu_read_lock();
381 			list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
382 				if (server->pnfs_curr_ld &&
383 				    server->pnfs_curr_ld->id == dev->cbd_layout_type) {
384 					rcu_read_unlock();
385 					goto found;
386 				}
387 			rcu_read_unlock();
388 			continue;
389 		}
390 
391 	found:
392 		nfs4_delete_deviceid(server->pnfs_curr_ld, clp, &dev->cbd_dev_id);
393 	}
394 
395 out:
396 	kfree(args->devs);
397 	return res;
398 }
399 
400 /*
401  * Validate the sequenceID sent by the server.
402  * Return success if the sequenceID is one more than what we last saw on
403  * this slot, accounting for wraparound.  Increments the slot's sequence.
404  *
405  * We don't yet implement a duplicate request cache, instead we set the
406  * back channel ca_maxresponsesize_cached to zero. This is OK for now
407  * since we only currently implement idempotent callbacks anyway.
408  *
409  * We have a single slot backchannel at this time, so we don't bother
410  * checking the used_slots bit array on the table.  The lower layer guarantees
411  * a single outstanding callback request at a time.
412  */
413 static __be32
414 validate_seqid(const struct nfs4_slot_table *tbl, const struct nfs4_slot *slot,
415 		const struct cb_sequenceargs * args)
416 {
417 	if (args->csa_slotid > tbl->server_highest_slotid)
418 		return htonl(NFS4ERR_BADSLOT);
419 
420 	/* Replay */
421 	if (args->csa_sequenceid == slot->seq_nr) {
422 		if (nfs4_test_locked_slot(tbl, slot->slot_nr))
423 			return htonl(NFS4ERR_DELAY);
424 		/* Signal process_op to set this error on next op */
425 		if (args->csa_cachethis == 0)
426 			return htonl(NFS4ERR_RETRY_UNCACHED_REP);
427 
428 		/* Liar! We never allowed you to set csa_cachethis != 0 */
429 		return htonl(NFS4ERR_SEQ_FALSE_RETRY);
430 	}
431 
432 	/* Note: wraparound relies on seq_nr being of type u32 */
433 	if (likely(args->csa_sequenceid == slot->seq_nr + 1))
434 		return htonl(NFS4_OK);
435 
436 	/* Misordered request */
437 	return htonl(NFS4ERR_SEQ_MISORDERED);
438 }
439 
440 /*
441  * For each referring call triple, check the session's slot table for
442  * a match.  If the slot is in use and the sequence numbers match, the
443  * client is still waiting for a response to the original request.
444  */
445 static int referring_call_exists(struct nfs_client *clp,
446 				  uint32_t nrclists,
447 				  struct referring_call_list *rclists,
448 				  spinlock_t *lock)
449 	__releases(lock)
450 	__acquires(lock)
451 {
452 	int status = 0;
453 	int i, j;
454 	struct nfs4_session *session;
455 	struct nfs4_slot_table *tbl;
456 	struct referring_call_list *rclist;
457 	struct referring_call *ref;
458 
459 	/*
460 	 * XXX When client trunking is implemented, this becomes
461 	 * a session lookup from within the loop
462 	 */
463 	session = clp->cl_session;
464 	tbl = &session->fc_slot_table;
465 
466 	for (i = 0; i < nrclists; i++) {
467 		rclist = &rclists[i];
468 		if (memcmp(session->sess_id.data,
469 			   rclist->rcl_sessionid.data,
470 			   NFS4_MAX_SESSIONID_LEN) != 0)
471 			continue;
472 
473 		for (j = 0; j < rclist->rcl_nrefcalls; j++) {
474 			ref = &rclist->rcl_refcalls[j];
475 			spin_unlock(lock);
476 			status = nfs4_slot_wait_on_seqid(tbl, ref->rc_slotid,
477 					ref->rc_sequenceid, HZ >> 1) < 0;
478 			spin_lock(lock);
479 			if (status)
480 				goto out;
481 		}
482 	}
483 
484 out:
485 	return status;
486 }
487 
488 __be32 nfs4_callback_sequence(void *argp, void *resp,
489 			      struct cb_process_state *cps)
490 {
491 	struct cb_sequenceargs *args = argp;
492 	struct cb_sequenceres *res = resp;
493 	struct nfs4_slot_table *tbl;
494 	struct nfs4_slot *slot;
495 	struct nfs_client *clp;
496 	int i;
497 	__be32 status = htonl(NFS4ERR_BADSESSION);
498 
499 	clp = nfs4_find_client_sessionid(cps->net, args->csa_addr,
500 					 &args->csa_sessionid, cps->minorversion);
501 	if (clp == NULL)
502 		goto out;
503 
504 	if (!(clp->cl_session->flags & SESSION4_BACK_CHAN))
505 		goto out;
506 
507 	tbl = &clp->cl_session->bc_slot_table;
508 
509 	/* Set up res before grabbing the spinlock */
510 	memcpy(&res->csr_sessionid, &args->csa_sessionid,
511 	       sizeof(res->csr_sessionid));
512 	res->csr_sequenceid = args->csa_sequenceid;
513 	res->csr_slotid = args->csa_slotid;
514 
515 	spin_lock(&tbl->slot_tbl_lock);
516 	/* state manager is resetting the session */
517 	if (test_bit(NFS4_SLOT_TBL_DRAINING, &tbl->slot_tbl_state)) {
518 		status = htonl(NFS4ERR_DELAY);
519 		/* Return NFS4ERR_BADSESSION if we're draining the session
520 		 * in order to reset it.
521 		 */
522 		if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state))
523 			status = htonl(NFS4ERR_BADSESSION);
524 		goto out_unlock;
525 	}
526 
527 	status = htonl(NFS4ERR_BADSLOT);
528 	slot = nfs4_lookup_slot(tbl, args->csa_slotid);
529 	if (IS_ERR(slot))
530 		goto out_unlock;
531 
532 	res->csr_highestslotid = tbl->server_highest_slotid;
533 	res->csr_target_highestslotid = tbl->target_highest_slotid;
534 
535 	status = validate_seqid(tbl, slot, args);
536 	if (status)
537 		goto out_unlock;
538 	if (!nfs4_try_to_lock_slot(tbl, slot)) {
539 		status = htonl(NFS4ERR_DELAY);
540 		goto out_unlock;
541 	}
542 	cps->slot = slot;
543 
544 	/* The ca_maxresponsesize_cached is 0 with no DRC */
545 	if (args->csa_cachethis != 0) {
546 		status = htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE);
547 		goto out_unlock;
548 	}
549 
550 	/*
551 	 * Check for pending referring calls.  If a match is found, a
552 	 * related callback was received before the response to the original
553 	 * call.
554 	 */
555 	if (referring_call_exists(clp, args->csa_nrclists, args->csa_rclists,
556 				&tbl->slot_tbl_lock) < 0) {
557 		status = htonl(NFS4ERR_DELAY);
558 		goto out_unlock;
559 	}
560 
561 	/*
562 	 * RFC5661 20.9.3
563 	 * If CB_SEQUENCE returns an error, then the state of the slot
564 	 * (sequence ID, cached reply) MUST NOT change.
565 	 */
566 	slot->seq_nr = args->csa_sequenceid;
567 out_unlock:
568 	spin_unlock(&tbl->slot_tbl_lock);
569 
570 out:
571 	cps->clp = clp; /* put in nfs4_callback_compound */
572 	for (i = 0; i < args->csa_nrclists; i++)
573 		kfree(args->csa_rclists[i].rcl_refcalls);
574 	kfree(args->csa_rclists);
575 
576 	if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) {
577 		cps->drc_status = status;
578 		status = 0;
579 	} else
580 		res->csr_status = status;
581 
582 	trace_nfs4_cb_sequence(args, res, status);
583 	return status;
584 }
585 
586 static bool
587 validate_bitmap_values(unsigned int mask)
588 {
589 	return (mask & ~RCA4_TYPE_MASK_ALL) == 0;
590 }
591 
592 __be32 nfs4_callback_recallany(void *argp, void *resp,
593 			       struct cb_process_state *cps)
594 {
595 	struct cb_recallanyargs *args = argp;
596 	__be32 status;
597 	fmode_t flags = 0;
598 
599 	status = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
600 	if (!cps->clp) /* set in cb_sequence */
601 		goto out;
602 
603 	dprintk_rcu("NFS: RECALL_ANY callback request from %s\n",
604 		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
605 
606 	status = cpu_to_be32(NFS4ERR_INVAL);
607 	if (!validate_bitmap_values(args->craa_type_mask))
608 		goto out;
609 
610 	status = cpu_to_be32(NFS4_OK);
611 	if (args->craa_type_mask & BIT(RCA4_TYPE_MASK_RDATA_DLG))
612 		flags = FMODE_READ;
613 	if (args->craa_type_mask & BIT(RCA4_TYPE_MASK_WDATA_DLG))
614 		flags |= FMODE_WRITE;
615 	if (flags)
616 		nfs_expire_unused_delegation_types(cps->clp, flags);
617 
618 	if (args->craa_type_mask & BIT(RCA4_TYPE_MASK_FILE_LAYOUT))
619 		pnfs_recall_all_layouts(cps->clp);
620 out:
621 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
622 	return status;
623 }
624 
625 /* Reduce the fore channel's max_slots to the target value */
626 __be32 nfs4_callback_recallslot(void *argp, void *resp,
627 				struct cb_process_state *cps)
628 {
629 	struct cb_recallslotargs *args = argp;
630 	struct nfs4_slot_table *fc_tbl;
631 	__be32 status;
632 
633 	status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
634 	if (!cps->clp) /* set in cb_sequence */
635 		goto out;
636 
637 	dprintk_rcu("NFS: CB_RECALL_SLOT request from %s target highest slotid %u\n",
638 		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR),
639 		args->crsa_target_highest_slotid);
640 
641 	fc_tbl = &cps->clp->cl_session->fc_slot_table;
642 
643 	status = htonl(NFS4_OK);
644 
645 	nfs41_set_target_slotid(fc_tbl, args->crsa_target_highest_slotid);
646 	nfs41_notify_server(cps->clp);
647 out:
648 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
649 	return status;
650 }
651 
652 __be32 nfs4_callback_notify_lock(void *argp, void *resp,
653 				 struct cb_process_state *cps)
654 {
655 	struct cb_notify_lock_args *args = argp;
656 
657 	if (!cps->clp) /* set in cb_sequence */
658 		return htonl(NFS4ERR_OP_NOT_IN_SESSION);
659 
660 	dprintk_rcu("NFS: CB_NOTIFY_LOCK request from %s\n",
661 		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
662 
663 	/* Don't wake anybody if the string looked bogus */
664 	if (args->cbnl_valid)
665 		__wake_up(&cps->clp->cl_lock_waitq, TASK_NORMAL, 0, args);
666 
667 	return htonl(NFS4_OK);
668 }
669 #endif /* CONFIG_NFS_V4_1 */
670 #ifdef CONFIG_NFS_V4_2
671 static void nfs4_copy_cb_args(struct nfs4_copy_state *cp_state,
672 				struct cb_offloadargs *args)
673 {
674 	cp_state->count = args->wr_count;
675 	cp_state->error = args->error;
676 	if (!args->error) {
677 		cp_state->verf.committed = args->wr_writeverf.committed;
678 		memcpy(&cp_state->verf.verifier.data[0],
679 			&args->wr_writeverf.verifier.data[0],
680 			NFS4_VERIFIER_SIZE);
681 	}
682 }
683 
684 __be32 nfs4_callback_offload(void *data, void *dummy,
685 			     struct cb_process_state *cps)
686 {
687 	struct cb_offloadargs *args = data;
688 	struct nfs_server *server;
689 	struct nfs4_copy_state *copy, *tmp_copy;
690 	bool found = false;
691 
692 	copy = kzalloc(sizeof(struct nfs4_copy_state), GFP_NOFS);
693 	if (!copy)
694 		return htonl(NFS4ERR_SERVERFAULT);
695 
696 	spin_lock(&cps->clp->cl_lock);
697 	rcu_read_lock();
698 	list_for_each_entry_rcu(server, &cps->clp->cl_superblocks,
699 				client_link) {
700 		list_for_each_entry(tmp_copy, &server->ss_copies, copies) {
701 			if (memcmp(args->coa_stateid.other,
702 					tmp_copy->stateid.other,
703 					sizeof(args->coa_stateid.other)))
704 				continue;
705 			nfs4_copy_cb_args(tmp_copy, args);
706 			complete(&tmp_copy->completion);
707 			found = true;
708 			goto out;
709 		}
710 	}
711 out:
712 	rcu_read_unlock();
713 	if (!found) {
714 		memcpy(&copy->stateid, &args->coa_stateid, NFS4_STATEID_SIZE);
715 		nfs4_copy_cb_args(copy, args);
716 		list_add_tail(&copy->copies, &cps->clp->pending_cb_stateids);
717 	} else
718 		kfree(copy);
719 	spin_unlock(&cps->clp->cl_lock);
720 
721 	return 0;
722 }
723 #endif /* CONFIG_NFS_V4_2 */
724