xref: /openbmc/linux/fs/nfs/pnfs_nfs.c (revision f125e2d4)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Common NFS I/O  operations for the pnfs file based
4  * layout drivers.
5  *
6  * Copyright (c) 2014, Primary Data, Inc. All rights reserved.
7  *
8  * Tom Haynes <loghyr@primarydata.com>
9  */
10 
11 #include <linux/nfs_fs.h>
12 #include <linux/nfs_page.h>
13 #include <linux/sunrpc/addr.h>
14 #include <linux/module.h>
15 
16 #include "nfs4session.h"
17 #include "internal.h"
18 #include "pnfs.h"
19 
20 #define NFSDBG_FACILITY		NFSDBG_PNFS
21 
22 void pnfs_generic_rw_release(void *data)
23 {
24 	struct nfs_pgio_header *hdr = data;
25 
26 	nfs_put_client(hdr->ds_clp);
27 	hdr->mds_ops->rpc_release(data);
28 }
29 EXPORT_SYMBOL_GPL(pnfs_generic_rw_release);
30 
31 /* Fake up some data that will cause nfs_commit_release to retry the writes. */
32 void pnfs_generic_prepare_to_resend_writes(struct nfs_commit_data *data)
33 {
34 	struct nfs_writeverf *verf = data->res.verf;
35 
36 	data->task.tk_status = 0;
37 	memset(&verf->verifier, 0, sizeof(verf->verifier));
38 	verf->committed = NFS_UNSTABLE;
39 }
40 EXPORT_SYMBOL_GPL(pnfs_generic_prepare_to_resend_writes);
41 
42 void pnfs_generic_write_commit_done(struct rpc_task *task, void *data)
43 {
44 	struct nfs_commit_data *wdata = data;
45 
46 	/* Note this may cause RPC to be resent */
47 	wdata->mds_ops->rpc_call_done(task, data);
48 }
49 EXPORT_SYMBOL_GPL(pnfs_generic_write_commit_done);
50 
51 void pnfs_generic_commit_release(void *calldata)
52 {
53 	struct nfs_commit_data *data = calldata;
54 
55 	data->completion_ops->completion(data);
56 	pnfs_put_lseg(data->lseg);
57 	nfs_put_client(data->ds_clp);
58 	nfs_commitdata_release(data);
59 }
60 EXPORT_SYMBOL_GPL(pnfs_generic_commit_release);
61 
62 /* The generic layer is about to remove the req from the commit list.
63  * If this will make the bucket empty, it will need to put the lseg reference.
64  * Note this must be called holding nfsi->commit_mutex
65  */
66 void
67 pnfs_generic_clear_request_commit(struct nfs_page *req,
68 				  struct nfs_commit_info *cinfo)
69 {
70 	struct pnfs_layout_segment *freeme = NULL;
71 
72 	if (!test_and_clear_bit(PG_COMMIT_TO_DS, &req->wb_flags))
73 		goto out;
74 	cinfo->ds->nwritten--;
75 	if (list_is_singular(&req->wb_list)) {
76 		struct pnfs_commit_bucket *bucket;
77 
78 		bucket = list_first_entry(&req->wb_list,
79 					  struct pnfs_commit_bucket,
80 					  written);
81 		freeme = bucket->wlseg;
82 		bucket->wlseg = NULL;
83 	}
84 out:
85 	nfs_request_remove_commit_list(req, cinfo);
86 	pnfs_put_lseg(freeme);
87 }
88 EXPORT_SYMBOL_GPL(pnfs_generic_clear_request_commit);
89 
90 static int
91 pnfs_generic_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
92 				 struct nfs_commit_info *cinfo,
93 				 int max)
94 {
95 	struct list_head *src = &bucket->written;
96 	struct list_head *dst = &bucket->committing;
97 	int ret;
98 
99 	lockdep_assert_held(&NFS_I(cinfo->inode)->commit_mutex);
100 	ret = nfs_scan_commit_list(src, dst, cinfo, max);
101 	if (ret) {
102 		cinfo->ds->nwritten -= ret;
103 		cinfo->ds->ncommitting += ret;
104 		if (bucket->clseg == NULL)
105 			bucket->clseg = pnfs_get_lseg(bucket->wlseg);
106 		if (list_empty(src)) {
107 			pnfs_put_lseg(bucket->wlseg);
108 			bucket->wlseg = NULL;
109 		}
110 	}
111 	return ret;
112 }
113 
114 /* Move reqs from written to committing lists, returning count
115  * of number moved.
116  */
117 int pnfs_generic_scan_commit_lists(struct nfs_commit_info *cinfo,
118 				   int max)
119 {
120 	int i, rv = 0, cnt;
121 
122 	lockdep_assert_held(&NFS_I(cinfo->inode)->commit_mutex);
123 	for (i = 0; i < cinfo->ds->nbuckets && max != 0; i++) {
124 		cnt = pnfs_generic_scan_ds_commit_list(&cinfo->ds->buckets[i],
125 						       cinfo, max);
126 		max -= cnt;
127 		rv += cnt;
128 	}
129 	return rv;
130 }
131 EXPORT_SYMBOL_GPL(pnfs_generic_scan_commit_lists);
132 
133 /* Pull everything off the committing lists and dump into @dst.  */
134 void pnfs_generic_recover_commit_reqs(struct list_head *dst,
135 				      struct nfs_commit_info *cinfo)
136 {
137 	struct pnfs_commit_bucket *b;
138 	struct pnfs_layout_segment *freeme;
139 	int nwritten;
140 	int i;
141 
142 	lockdep_assert_held(&NFS_I(cinfo->inode)->commit_mutex);
143 restart:
144 	for (i = 0, b = cinfo->ds->buckets; i < cinfo->ds->nbuckets; i++, b++) {
145 		nwritten = nfs_scan_commit_list(&b->written, dst, cinfo, 0);
146 		if (!nwritten)
147 			continue;
148 		cinfo->ds->nwritten -= nwritten;
149 		if (list_empty(&b->written)) {
150 			freeme = b->wlseg;
151 			b->wlseg = NULL;
152 			pnfs_put_lseg(freeme);
153 			goto restart;
154 		}
155 	}
156 }
157 EXPORT_SYMBOL_GPL(pnfs_generic_recover_commit_reqs);
158 
159 static void pnfs_generic_retry_commit(struct nfs_commit_info *cinfo, int idx)
160 {
161 	struct pnfs_ds_commit_info *fl_cinfo = cinfo->ds;
162 	struct pnfs_commit_bucket *bucket;
163 	struct pnfs_layout_segment *freeme;
164 	struct list_head *pos;
165 	LIST_HEAD(pages);
166 	int i;
167 
168 	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
169 	for (i = idx; i < fl_cinfo->nbuckets; i++) {
170 		bucket = &fl_cinfo->buckets[i];
171 		if (list_empty(&bucket->committing))
172 			continue;
173 		freeme = bucket->clseg;
174 		bucket->clseg = NULL;
175 		list_for_each(pos, &bucket->committing)
176 			cinfo->ds->ncommitting--;
177 		list_splice_init(&bucket->committing, &pages);
178 		mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
179 		nfs_retry_commit(&pages, freeme, cinfo, i);
180 		pnfs_put_lseg(freeme);
181 		mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
182 	}
183 	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
184 }
185 
186 static unsigned int
187 pnfs_generic_alloc_ds_commits(struct nfs_commit_info *cinfo,
188 			      struct list_head *list)
189 {
190 	struct pnfs_ds_commit_info *fl_cinfo;
191 	struct pnfs_commit_bucket *bucket;
192 	struct nfs_commit_data *data;
193 	int i;
194 	unsigned int nreq = 0;
195 
196 	fl_cinfo = cinfo->ds;
197 	bucket = fl_cinfo->buckets;
198 	for (i = 0; i < fl_cinfo->nbuckets; i++, bucket++) {
199 		if (list_empty(&bucket->committing))
200 			continue;
201 		data = nfs_commitdata_alloc(false);
202 		if (!data)
203 			break;
204 		data->ds_commit_index = i;
205 		list_add(&data->pages, list);
206 		nreq++;
207 	}
208 
209 	/* Clean up on error */
210 	pnfs_generic_retry_commit(cinfo, i);
211 	return nreq;
212 }
213 
214 static inline
215 void pnfs_fetch_commit_bucket_list(struct list_head *pages,
216 		struct nfs_commit_data *data,
217 		struct nfs_commit_info *cinfo)
218 {
219 	struct pnfs_commit_bucket *bucket;
220 	struct list_head *pos;
221 
222 	bucket = &cinfo->ds->buckets[data->ds_commit_index];
223 	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
224 	list_for_each(pos, &bucket->committing)
225 		cinfo->ds->ncommitting--;
226 	list_splice_init(&bucket->committing, pages);
227 	data->lseg = bucket->clseg;
228 	bucket->clseg = NULL;
229 	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
230 
231 }
232 
233 /* Helper function for pnfs_generic_commit_pagelist to catch an empty
234  * page list. This can happen when two commits race.
235  *
236  * This must be called instead of nfs_init_commit - call one or the other, but
237  * not both!
238  */
239 static bool
240 pnfs_generic_commit_cancel_empty_pagelist(struct list_head *pages,
241 					  struct nfs_commit_data *data,
242 					  struct nfs_commit_info *cinfo)
243 {
244 	if (list_empty(pages)) {
245 		if (atomic_dec_and_test(&cinfo->mds->rpcs_out))
246 			wake_up_var(&cinfo->mds->rpcs_out);
247 		/* don't call nfs_commitdata_release - it tries to put
248 		 * the open_context which is not acquired until nfs_init_commit
249 		 * which has not been called on @data */
250 		WARN_ON_ONCE(data->context);
251 		nfs_commit_free(data);
252 		return true;
253 	}
254 
255 	return false;
256 }
257 
258 /* This follows nfs_commit_list pretty closely */
259 int
260 pnfs_generic_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
261 			     int how, struct nfs_commit_info *cinfo,
262 			     int (*initiate_commit)(struct nfs_commit_data *data,
263 						    int how))
264 {
265 	struct nfs_commit_data *data, *tmp;
266 	LIST_HEAD(list);
267 	unsigned int nreq = 0;
268 
269 	if (!list_empty(mds_pages)) {
270 		data = nfs_commitdata_alloc(true);
271 		data->ds_commit_index = -1;
272 		list_add(&data->pages, &list);
273 		nreq++;
274 	}
275 
276 	nreq += pnfs_generic_alloc_ds_commits(cinfo, &list);
277 
278 	if (nreq == 0)
279 		goto out;
280 
281 	atomic_add(nreq, &cinfo->mds->rpcs_out);
282 
283 	list_for_each_entry_safe(data, tmp, &list, pages) {
284 		list_del_init(&data->pages);
285 		if (data->ds_commit_index < 0) {
286 			/* another commit raced with us */
287 			if (pnfs_generic_commit_cancel_empty_pagelist(mds_pages,
288 				data, cinfo))
289 				continue;
290 
291 			nfs_init_commit(data, mds_pages, NULL, cinfo);
292 			nfs_initiate_commit(NFS_CLIENT(inode), data,
293 					    NFS_PROTO(data->inode),
294 					    data->mds_ops, how, 0);
295 		} else {
296 			LIST_HEAD(pages);
297 
298 			pnfs_fetch_commit_bucket_list(&pages, data, cinfo);
299 
300 			/* another commit raced with us */
301 			if (pnfs_generic_commit_cancel_empty_pagelist(&pages,
302 				data, cinfo))
303 				continue;
304 
305 			nfs_init_commit(data, &pages, data->lseg, cinfo);
306 			initiate_commit(data, how);
307 		}
308 	}
309 out:
310 	return PNFS_ATTEMPTED;
311 }
312 EXPORT_SYMBOL_GPL(pnfs_generic_commit_pagelist);
313 
314 /*
315  * Data server cache
316  *
317  * Data servers can be mapped to different device ids.
318  * nfs4_pnfs_ds reference counting
319  *   - set to 1 on allocation
320  *   - incremented when a device id maps a data server already in the cache.
321  *   - decremented when deviceid is removed from the cache.
322  */
323 static DEFINE_SPINLOCK(nfs4_ds_cache_lock);
324 static LIST_HEAD(nfs4_data_server_cache);
325 
326 /* Debug routines */
327 static void
328 print_ds(struct nfs4_pnfs_ds *ds)
329 {
330 	if (ds == NULL) {
331 		printk(KERN_WARNING "%s NULL device\n", __func__);
332 		return;
333 	}
334 	printk(KERN_WARNING "        ds %s\n"
335 		"        ref count %d\n"
336 		"        client %p\n"
337 		"        cl_exchange_flags %x\n",
338 		ds->ds_remotestr,
339 		refcount_read(&ds->ds_count), ds->ds_clp,
340 		ds->ds_clp ? ds->ds_clp->cl_exchange_flags : 0);
341 }
342 
343 static bool
344 same_sockaddr(struct sockaddr *addr1, struct sockaddr *addr2)
345 {
346 	struct sockaddr_in *a, *b;
347 	struct sockaddr_in6 *a6, *b6;
348 
349 	if (addr1->sa_family != addr2->sa_family)
350 		return false;
351 
352 	switch (addr1->sa_family) {
353 	case AF_INET:
354 		a = (struct sockaddr_in *)addr1;
355 		b = (struct sockaddr_in *)addr2;
356 
357 		if (a->sin_addr.s_addr == b->sin_addr.s_addr &&
358 		    a->sin_port == b->sin_port)
359 			return true;
360 		break;
361 
362 	case AF_INET6:
363 		a6 = (struct sockaddr_in6 *)addr1;
364 		b6 = (struct sockaddr_in6 *)addr2;
365 
366 		/* LINKLOCAL addresses must have matching scope_id */
367 		if (ipv6_addr_src_scope(&a6->sin6_addr) ==
368 		    IPV6_ADDR_SCOPE_LINKLOCAL &&
369 		    a6->sin6_scope_id != b6->sin6_scope_id)
370 			return false;
371 
372 		if (ipv6_addr_equal(&a6->sin6_addr, &b6->sin6_addr) &&
373 		    a6->sin6_port == b6->sin6_port)
374 			return true;
375 		break;
376 
377 	default:
378 		dprintk("%s: unhandled address family: %u\n",
379 			__func__, addr1->sa_family);
380 		return false;
381 	}
382 
383 	return false;
384 }
385 
386 /*
387  * Checks if 'dsaddrs1' contains a subset of 'dsaddrs2'. If it does,
388  * declare a match.
389  */
390 static bool
391 _same_data_server_addrs_locked(const struct list_head *dsaddrs1,
392 			       const struct list_head *dsaddrs2)
393 {
394 	struct nfs4_pnfs_ds_addr *da1, *da2;
395 	struct sockaddr *sa1, *sa2;
396 	bool match = false;
397 
398 	list_for_each_entry(da1, dsaddrs1, da_node) {
399 		sa1 = (struct sockaddr *)&da1->da_addr;
400 		match = false;
401 		list_for_each_entry(da2, dsaddrs2, da_node) {
402 			sa2 = (struct sockaddr *)&da2->da_addr;
403 			match = same_sockaddr(sa1, sa2);
404 			if (match)
405 				break;
406 		}
407 		if (!match)
408 			break;
409 	}
410 	return match;
411 }
412 
413 /*
414  * Lookup DS by addresses.  nfs4_ds_cache_lock is held
415  */
416 static struct nfs4_pnfs_ds *
417 _data_server_lookup_locked(const struct list_head *dsaddrs)
418 {
419 	struct nfs4_pnfs_ds *ds;
420 
421 	list_for_each_entry(ds, &nfs4_data_server_cache, ds_node)
422 		if (_same_data_server_addrs_locked(&ds->ds_addrs, dsaddrs))
423 			return ds;
424 	return NULL;
425 }
426 
427 static void destroy_ds(struct nfs4_pnfs_ds *ds)
428 {
429 	struct nfs4_pnfs_ds_addr *da;
430 
431 	dprintk("--> %s\n", __func__);
432 	ifdebug(FACILITY)
433 		print_ds(ds);
434 
435 	nfs_put_client(ds->ds_clp);
436 
437 	while (!list_empty(&ds->ds_addrs)) {
438 		da = list_first_entry(&ds->ds_addrs,
439 				      struct nfs4_pnfs_ds_addr,
440 				      da_node);
441 		list_del_init(&da->da_node);
442 		kfree(da->da_remotestr);
443 		kfree(da);
444 	}
445 
446 	kfree(ds->ds_remotestr);
447 	kfree(ds);
448 }
449 
450 void nfs4_pnfs_ds_put(struct nfs4_pnfs_ds *ds)
451 {
452 	if (refcount_dec_and_lock(&ds->ds_count,
453 				&nfs4_ds_cache_lock)) {
454 		list_del_init(&ds->ds_node);
455 		spin_unlock(&nfs4_ds_cache_lock);
456 		destroy_ds(ds);
457 	}
458 }
459 EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_put);
460 
461 /*
462  * Create a string with a human readable address and port to avoid
463  * complicated setup around many dprinks.
464  */
465 static char *
466 nfs4_pnfs_remotestr(struct list_head *dsaddrs, gfp_t gfp_flags)
467 {
468 	struct nfs4_pnfs_ds_addr *da;
469 	char *remotestr;
470 	size_t len;
471 	char *p;
472 
473 	len = 3;        /* '{', '}' and eol */
474 	list_for_each_entry(da, dsaddrs, da_node) {
475 		len += strlen(da->da_remotestr) + 1;    /* string plus comma */
476 	}
477 
478 	remotestr = kzalloc(len, gfp_flags);
479 	if (!remotestr)
480 		return NULL;
481 
482 	p = remotestr;
483 	*(p++) = '{';
484 	len--;
485 	list_for_each_entry(da, dsaddrs, da_node) {
486 		size_t ll = strlen(da->da_remotestr);
487 
488 		if (ll > len)
489 			goto out_err;
490 
491 		memcpy(p, da->da_remotestr, ll);
492 		p += ll;
493 		len -= ll;
494 
495 		if (len < 1)
496 			goto out_err;
497 		(*p++) = ',';
498 		len--;
499 	}
500 	if (len < 2)
501 		goto out_err;
502 	*(p++) = '}';
503 	*p = '\0';
504 	return remotestr;
505 out_err:
506 	kfree(remotestr);
507 	return NULL;
508 }
509 
510 /*
511  * Given a list of multipath struct nfs4_pnfs_ds_addr, add it to ds cache if
512  * uncached and return cached struct nfs4_pnfs_ds.
513  */
514 struct nfs4_pnfs_ds *
515 nfs4_pnfs_ds_add(struct list_head *dsaddrs, gfp_t gfp_flags)
516 {
517 	struct nfs4_pnfs_ds *tmp_ds, *ds = NULL;
518 	char *remotestr;
519 
520 	if (list_empty(dsaddrs)) {
521 		dprintk("%s: no addresses defined\n", __func__);
522 		goto out;
523 	}
524 
525 	ds = kzalloc(sizeof(*ds), gfp_flags);
526 	if (!ds)
527 		goto out;
528 
529 	/* this is only used for debugging, so it's ok if its NULL */
530 	remotestr = nfs4_pnfs_remotestr(dsaddrs, gfp_flags);
531 
532 	spin_lock(&nfs4_ds_cache_lock);
533 	tmp_ds = _data_server_lookup_locked(dsaddrs);
534 	if (tmp_ds == NULL) {
535 		INIT_LIST_HEAD(&ds->ds_addrs);
536 		list_splice_init(dsaddrs, &ds->ds_addrs);
537 		ds->ds_remotestr = remotestr;
538 		refcount_set(&ds->ds_count, 1);
539 		INIT_LIST_HEAD(&ds->ds_node);
540 		ds->ds_clp = NULL;
541 		list_add(&ds->ds_node, &nfs4_data_server_cache);
542 		dprintk("%s add new data server %s\n", __func__,
543 			ds->ds_remotestr);
544 	} else {
545 		kfree(remotestr);
546 		kfree(ds);
547 		refcount_inc(&tmp_ds->ds_count);
548 		dprintk("%s data server %s found, inc'ed ds_count to %d\n",
549 			__func__, tmp_ds->ds_remotestr,
550 			refcount_read(&tmp_ds->ds_count));
551 		ds = tmp_ds;
552 	}
553 	spin_unlock(&nfs4_ds_cache_lock);
554 out:
555 	return ds;
556 }
557 EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_add);
558 
559 static void nfs4_wait_ds_connect(struct nfs4_pnfs_ds *ds)
560 {
561 	might_sleep();
562 	wait_on_bit(&ds->ds_state, NFS4DS_CONNECTING,
563 			TASK_KILLABLE);
564 }
565 
566 static void nfs4_clear_ds_conn_bit(struct nfs4_pnfs_ds *ds)
567 {
568 	smp_mb__before_atomic();
569 	clear_bit(NFS4DS_CONNECTING, &ds->ds_state);
570 	smp_mb__after_atomic();
571 	wake_up_bit(&ds->ds_state, NFS4DS_CONNECTING);
572 }
573 
574 static struct nfs_client *(*get_v3_ds_connect)(
575 			struct nfs_server *mds_srv,
576 			const struct sockaddr *ds_addr,
577 			int ds_addrlen,
578 			int ds_proto,
579 			unsigned int ds_timeo,
580 			unsigned int ds_retrans);
581 
582 static bool load_v3_ds_connect(void)
583 {
584 	if (!get_v3_ds_connect) {
585 		get_v3_ds_connect = symbol_request(nfs3_set_ds_client);
586 		WARN_ON_ONCE(!get_v3_ds_connect);
587 	}
588 
589 	return(get_v3_ds_connect != NULL);
590 }
591 
592 void nfs4_pnfs_v3_ds_connect_unload(void)
593 {
594 	if (get_v3_ds_connect) {
595 		symbol_put(nfs3_set_ds_client);
596 		get_v3_ds_connect = NULL;
597 	}
598 }
599 
600 static int _nfs4_pnfs_v3_ds_connect(struct nfs_server *mds_srv,
601 				 struct nfs4_pnfs_ds *ds,
602 				 unsigned int timeo,
603 				 unsigned int retrans)
604 {
605 	struct nfs_client *clp = ERR_PTR(-EIO);
606 	struct nfs4_pnfs_ds_addr *da;
607 	int status = 0;
608 
609 	dprintk("--> %s DS %s\n", __func__, ds->ds_remotestr);
610 
611 	if (!load_v3_ds_connect())
612 		goto out;
613 
614 	list_for_each_entry(da, &ds->ds_addrs, da_node) {
615 		dprintk("%s: DS %s: trying address %s\n",
616 			__func__, ds->ds_remotestr, da->da_remotestr);
617 
618 		if (!IS_ERR(clp)) {
619 			struct xprt_create xprt_args = {
620 				.ident = XPRT_TRANSPORT_TCP,
621 				.net = clp->cl_net,
622 				.dstaddr = (struct sockaddr *)&da->da_addr,
623 				.addrlen = da->da_addrlen,
624 				.servername = clp->cl_hostname,
625 			};
626 			/* Add this address as an alias */
627 			rpc_clnt_add_xprt(clp->cl_rpcclient, &xprt_args,
628 					rpc_clnt_test_and_add_xprt, NULL);
629 			continue;
630 		}
631 		clp = get_v3_ds_connect(mds_srv,
632 				(struct sockaddr *)&da->da_addr,
633 				da->da_addrlen, IPPROTO_TCP,
634 				timeo, retrans);
635 		if (IS_ERR(clp))
636 			continue;
637 		clp->cl_rpcclient->cl_softerr = 0;
638 		clp->cl_rpcclient->cl_softrtry = 0;
639 	}
640 
641 	if (IS_ERR(clp)) {
642 		status = PTR_ERR(clp);
643 		goto out;
644 	}
645 
646 	smp_wmb();
647 	ds->ds_clp = clp;
648 	dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr);
649 out:
650 	return status;
651 }
652 
653 static int _nfs4_pnfs_v4_ds_connect(struct nfs_server *mds_srv,
654 				 struct nfs4_pnfs_ds *ds,
655 				 unsigned int timeo,
656 				 unsigned int retrans,
657 				 u32 minor_version)
658 {
659 	struct nfs_client *clp = ERR_PTR(-EIO);
660 	struct nfs4_pnfs_ds_addr *da;
661 	int status = 0;
662 
663 	dprintk("--> %s DS %s\n", __func__, ds->ds_remotestr);
664 
665 	list_for_each_entry(da, &ds->ds_addrs, da_node) {
666 		dprintk("%s: DS %s: trying address %s\n",
667 			__func__, ds->ds_remotestr, da->da_remotestr);
668 
669 		if (!IS_ERR(clp) && clp->cl_mvops->session_trunk) {
670 			struct xprt_create xprt_args = {
671 				.ident = XPRT_TRANSPORT_TCP,
672 				.net = clp->cl_net,
673 				.dstaddr = (struct sockaddr *)&da->da_addr,
674 				.addrlen = da->da_addrlen,
675 				.servername = clp->cl_hostname,
676 			};
677 			struct nfs4_add_xprt_data xprtdata = {
678 				.clp = clp,
679 				.cred = nfs4_get_clid_cred(clp),
680 			};
681 			struct rpc_add_xprt_test rpcdata = {
682 				.add_xprt_test = clp->cl_mvops->session_trunk,
683 				.data = &xprtdata,
684 			};
685 
686 			/**
687 			* Test this address for session trunking and
688 			* add as an alias
689 			*/
690 			rpc_clnt_add_xprt(clp->cl_rpcclient, &xprt_args,
691 					  rpc_clnt_setup_test_and_add_xprt,
692 					  &rpcdata);
693 			if (xprtdata.cred)
694 				put_cred(xprtdata.cred);
695 		} else {
696 			clp = nfs4_set_ds_client(mds_srv,
697 						(struct sockaddr *)&da->da_addr,
698 						da->da_addrlen, IPPROTO_TCP,
699 						timeo, retrans, minor_version);
700 			if (IS_ERR(clp))
701 				continue;
702 
703 			status = nfs4_init_ds_session(clp,
704 					mds_srv->nfs_client->cl_lease_time);
705 			if (status) {
706 				nfs_put_client(clp);
707 				clp = ERR_PTR(-EIO);
708 				continue;
709 			}
710 
711 		}
712 	}
713 
714 	if (IS_ERR(clp)) {
715 		status = PTR_ERR(clp);
716 		goto out;
717 	}
718 
719 	smp_wmb();
720 	ds->ds_clp = clp;
721 	dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr);
722 out:
723 	return status;
724 }
725 
726 /*
727  * Create an rpc connection to the nfs4_pnfs_ds data server.
728  * Currently only supports IPv4 and IPv6 addresses.
729  * If connection fails, make devid unavailable and return a -errno.
730  */
731 int nfs4_pnfs_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds,
732 			  struct nfs4_deviceid_node *devid, unsigned int timeo,
733 			  unsigned int retrans, u32 version, u32 minor_version)
734 {
735 	int err;
736 
737 again:
738 	err = 0;
739 	if (test_and_set_bit(NFS4DS_CONNECTING, &ds->ds_state) == 0) {
740 		if (version == 3) {
741 			err = _nfs4_pnfs_v3_ds_connect(mds_srv, ds, timeo,
742 						       retrans);
743 		} else if (version == 4) {
744 			err = _nfs4_pnfs_v4_ds_connect(mds_srv, ds, timeo,
745 						       retrans, minor_version);
746 		} else {
747 			dprintk("%s: unsupported DS version %d\n", __func__,
748 				version);
749 			err = -EPROTONOSUPPORT;
750 		}
751 
752 		nfs4_clear_ds_conn_bit(ds);
753 	} else {
754 		nfs4_wait_ds_connect(ds);
755 
756 		/* what was waited on didn't connect AND didn't mark unavail */
757 		if (!ds->ds_clp && !nfs4_test_deviceid_unavailable(devid))
758 			goto again;
759 	}
760 
761 	/*
762 	 * At this point the ds->ds_clp should be ready, but it might have
763 	 * hit an error.
764 	 */
765 	if (!err) {
766 		if (!ds->ds_clp || !nfs_client_init_is_complete(ds->ds_clp)) {
767 			WARN_ON_ONCE(ds->ds_clp ||
768 				!nfs4_test_deviceid_unavailable(devid));
769 			return -EINVAL;
770 		}
771 		err = nfs_client_init_status(ds->ds_clp);
772 	}
773 
774 	return err;
775 }
776 EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_connect);
777 
778 /*
779  * Currently only supports ipv4, ipv6 and one multi-path address.
780  */
781 struct nfs4_pnfs_ds_addr *
782 nfs4_decode_mp_ds_addr(struct net *net, struct xdr_stream *xdr, gfp_t gfp_flags)
783 {
784 	struct nfs4_pnfs_ds_addr *da = NULL;
785 	char *buf, *portstr;
786 	__be16 port;
787 	int nlen, rlen;
788 	int tmp[2];
789 	__be32 *p;
790 	char *netid, *match_netid;
791 	size_t len, match_netid_len;
792 	char *startsep = "";
793 	char *endsep = "";
794 
795 
796 	/* r_netid */
797 	p = xdr_inline_decode(xdr, 4);
798 	if (unlikely(!p))
799 		goto out_err;
800 	nlen = be32_to_cpup(p++);
801 
802 	p = xdr_inline_decode(xdr, nlen);
803 	if (unlikely(!p))
804 		goto out_err;
805 
806 	netid = kmalloc(nlen+1, gfp_flags);
807 	if (unlikely(!netid))
808 		goto out_err;
809 
810 	netid[nlen] = '\0';
811 	memcpy(netid, p, nlen);
812 
813 	/* r_addr: ip/ip6addr with port in dec octets - see RFC 5665 */
814 	p = xdr_inline_decode(xdr, 4);
815 	if (unlikely(!p))
816 		goto out_free_netid;
817 	rlen = be32_to_cpup(p);
818 
819 	p = xdr_inline_decode(xdr, rlen);
820 	if (unlikely(!p))
821 		goto out_free_netid;
822 
823 	/* port is ".ABC.DEF", 8 chars max */
824 	if (rlen > INET6_ADDRSTRLEN + IPV6_SCOPE_ID_LEN + 8) {
825 		dprintk("%s: Invalid address, length %d\n", __func__,
826 			rlen);
827 		goto out_free_netid;
828 	}
829 	buf = kmalloc(rlen + 1, gfp_flags);
830 	if (!buf) {
831 		dprintk("%s: Not enough memory\n", __func__);
832 		goto out_free_netid;
833 	}
834 	buf[rlen] = '\0';
835 	memcpy(buf, p, rlen);
836 
837 	/* replace port '.' with '-' */
838 	portstr = strrchr(buf, '.');
839 	if (!portstr) {
840 		dprintk("%s: Failed finding expected dot in port\n",
841 			__func__);
842 		goto out_free_buf;
843 	}
844 	*portstr = '-';
845 
846 	/* find '.' between address and port */
847 	portstr = strrchr(buf, '.');
848 	if (!portstr) {
849 		dprintk("%s: Failed finding expected dot between address and "
850 			"port\n", __func__);
851 		goto out_free_buf;
852 	}
853 	*portstr = '\0';
854 
855 	da = kzalloc(sizeof(*da), gfp_flags);
856 	if (unlikely(!da))
857 		goto out_free_buf;
858 
859 	INIT_LIST_HEAD(&da->da_node);
860 
861 	if (!rpc_pton(net, buf, portstr-buf, (struct sockaddr *)&da->da_addr,
862 		      sizeof(da->da_addr))) {
863 		dprintk("%s: error parsing address %s\n", __func__, buf);
864 		goto out_free_da;
865 	}
866 
867 	portstr++;
868 	sscanf(portstr, "%d-%d", &tmp[0], &tmp[1]);
869 	port = htons((tmp[0] << 8) | (tmp[1]));
870 
871 	switch (da->da_addr.ss_family) {
872 	case AF_INET:
873 		((struct sockaddr_in *)&da->da_addr)->sin_port = port;
874 		da->da_addrlen = sizeof(struct sockaddr_in);
875 		match_netid = "tcp";
876 		match_netid_len = 3;
877 		break;
878 
879 	case AF_INET6:
880 		((struct sockaddr_in6 *)&da->da_addr)->sin6_port = port;
881 		da->da_addrlen = sizeof(struct sockaddr_in6);
882 		match_netid = "tcp6";
883 		match_netid_len = 4;
884 		startsep = "[";
885 		endsep = "]";
886 		break;
887 
888 	default:
889 		dprintk("%s: unsupported address family: %u\n",
890 			__func__, da->da_addr.ss_family);
891 		goto out_free_da;
892 	}
893 
894 	if (nlen != match_netid_len || strncmp(netid, match_netid, nlen)) {
895 		dprintk("%s: ERROR: r_netid \"%s\" != \"%s\"\n",
896 			__func__, netid, match_netid);
897 		goto out_free_da;
898 	}
899 
900 	/* save human readable address */
901 	len = strlen(startsep) + strlen(buf) + strlen(endsep) + 7;
902 	da->da_remotestr = kzalloc(len, gfp_flags);
903 
904 	/* NULL is ok, only used for dprintk */
905 	if (da->da_remotestr)
906 		snprintf(da->da_remotestr, len, "%s%s%s:%u", startsep,
907 			 buf, endsep, ntohs(port));
908 
909 	dprintk("%s: Parsed DS addr %s\n", __func__, da->da_remotestr);
910 	kfree(buf);
911 	kfree(netid);
912 	return da;
913 
914 out_free_da:
915 	kfree(da);
916 out_free_buf:
917 	dprintk("%s: Error parsing DS addr: %s\n", __func__, buf);
918 	kfree(buf);
919 out_free_netid:
920 	kfree(netid);
921 out_err:
922 	return NULL;
923 }
924 EXPORT_SYMBOL_GPL(nfs4_decode_mp_ds_addr);
925 
926 void
927 pnfs_layout_mark_request_commit(struct nfs_page *req,
928 				struct pnfs_layout_segment *lseg,
929 				struct nfs_commit_info *cinfo,
930 				u32 ds_commit_idx)
931 {
932 	struct list_head *list;
933 	struct pnfs_commit_bucket *buckets;
934 
935 	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
936 	buckets = cinfo->ds->buckets;
937 	list = &buckets[ds_commit_idx].written;
938 	if (list_empty(list)) {
939 		if (!pnfs_is_valid_lseg(lseg)) {
940 			mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
941 			cinfo->completion_ops->resched_write(cinfo, req);
942 			return;
943 		}
944 		/* Non-empty buckets hold a reference on the lseg.  That ref
945 		 * is normally transferred to the COMMIT call and released
946 		 * there.  It could also be released if the last req is pulled
947 		 * off due to a rewrite, in which case it will be done in
948 		 * pnfs_common_clear_request_commit
949 		 */
950 		WARN_ON_ONCE(buckets[ds_commit_idx].wlseg != NULL);
951 		buckets[ds_commit_idx].wlseg = pnfs_get_lseg(lseg);
952 	}
953 	set_bit(PG_COMMIT_TO_DS, &req->wb_flags);
954 	cinfo->ds->nwritten++;
955 
956 	nfs_request_add_commit_list_locked(req, list, cinfo);
957 	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
958 	nfs_mark_page_unstable(req->wb_page, cinfo);
959 }
960 EXPORT_SYMBOL_GPL(pnfs_layout_mark_request_commit);
961 
962 int
963 pnfs_nfs_generic_sync(struct inode *inode, bool datasync)
964 {
965 	int ret;
966 
967 	if (!pnfs_layoutcommit_outstanding(inode))
968 		return 0;
969 	ret = nfs_commit_inode(inode, FLUSH_SYNC);
970 	if (ret < 0)
971 		return ret;
972 	if (datasync)
973 		return 0;
974 	return pnfs_layoutcommit_inode(inode, true);
975 }
976 EXPORT_SYMBOL_GPL(pnfs_nfs_generic_sync);
977 
978