xref: /linux/fs/nfs/pnfs_nfs.c (revision a8b70ccf10e38775785d9cb12ead916474549f99)
1 /*
2  * Common NFS I/O  operations for the pnfs file based
3  * layout drivers.
4  *
5  * Copyright (c) 2014, Primary Data, Inc. All rights reserved.
6  *
7  * Tom Haynes <loghyr@primarydata.com>
8  */
9 
10 #include <linux/nfs_fs.h>
11 #include <linux/nfs_page.h>
12 #include <linux/sunrpc/addr.h>
13 #include <linux/module.h>
14 
15 #include "nfs4session.h"
16 #include "internal.h"
17 #include "pnfs.h"
18 
19 #define NFSDBG_FACILITY		NFSDBG_PNFS
20 
21 void pnfs_generic_rw_release(void *data)
22 {
23 	struct nfs_pgio_header *hdr = data;
24 
25 	nfs_put_client(hdr->ds_clp);
26 	hdr->mds_ops->rpc_release(data);
27 }
28 EXPORT_SYMBOL_GPL(pnfs_generic_rw_release);
29 
30 /* Fake up some data that will cause nfs_commit_release to retry the writes. */
31 void pnfs_generic_prepare_to_resend_writes(struct nfs_commit_data *data)
32 {
33 	struct nfs_page *first = nfs_list_entry(data->pages.next);
34 
35 	data->task.tk_status = 0;
36 	memcpy(&data->verf.verifier, &first->wb_verf,
37 	       sizeof(data->verf.verifier));
38 	data->verf.verifier.data[0]++; /* ensure verifier mismatch */
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 i_lock
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 			spin_unlock(&cinfo->inode->i_lock);
153 			pnfs_put_lseg(freeme);
154 			spin_lock(&cinfo->inode->i_lock);
155 			goto restart;
156 		}
157 	}
158 }
159 EXPORT_SYMBOL_GPL(pnfs_generic_recover_commit_reqs);
160 
161 static void pnfs_generic_retry_commit(struct nfs_commit_info *cinfo, int idx)
162 {
163 	struct pnfs_ds_commit_info *fl_cinfo = cinfo->ds;
164 	struct pnfs_commit_bucket *bucket;
165 	struct pnfs_layout_segment *freeme;
166 	struct list_head *pos;
167 	LIST_HEAD(pages);
168 	int i;
169 
170 	spin_lock(&cinfo->inode->i_lock);
171 	for (i = idx; i < fl_cinfo->nbuckets; i++) {
172 		bucket = &fl_cinfo->buckets[i];
173 		if (list_empty(&bucket->committing))
174 			continue;
175 		freeme = bucket->clseg;
176 		bucket->clseg = NULL;
177 		list_for_each(pos, &bucket->committing)
178 			cinfo->ds->ncommitting--;
179 		list_splice_init(&bucket->committing, &pages);
180 		spin_unlock(&cinfo->inode->i_lock);
181 		nfs_retry_commit(&pages, freeme, cinfo, i);
182 		pnfs_put_lseg(freeme);
183 		spin_lock(&cinfo->inode->i_lock);
184 	}
185 	spin_unlock(&cinfo->inode->i_lock);
186 }
187 
188 static unsigned int
189 pnfs_generic_alloc_ds_commits(struct nfs_commit_info *cinfo,
190 			      struct list_head *list)
191 {
192 	struct pnfs_ds_commit_info *fl_cinfo;
193 	struct pnfs_commit_bucket *bucket;
194 	struct nfs_commit_data *data;
195 	int i;
196 	unsigned int nreq = 0;
197 
198 	fl_cinfo = cinfo->ds;
199 	bucket = fl_cinfo->buckets;
200 	for (i = 0; i < fl_cinfo->nbuckets; i++, bucket++) {
201 		if (list_empty(&bucket->committing))
202 			continue;
203 		data = nfs_commitdata_alloc(false);
204 		if (!data)
205 			break;
206 		data->ds_commit_index = i;
207 		list_add(&data->pages, list);
208 		nreq++;
209 	}
210 
211 	/* Clean up on error */
212 	pnfs_generic_retry_commit(cinfo, i);
213 	return nreq;
214 }
215 
216 static inline
217 void pnfs_fetch_commit_bucket_list(struct list_head *pages,
218 		struct nfs_commit_data *data,
219 		struct nfs_commit_info *cinfo)
220 {
221 	struct pnfs_commit_bucket *bucket;
222 	struct list_head *pos;
223 
224 	bucket = &cinfo->ds->buckets[data->ds_commit_index];
225 	spin_lock(&cinfo->inode->i_lock);
226 	list_for_each(pos, &bucket->committing)
227 		cinfo->ds->ncommitting--;
228 	list_splice_init(&bucket->committing, pages);
229 	data->lseg = bucket->clseg;
230 	bucket->clseg = NULL;
231 	spin_unlock(&cinfo->inode->i_lock);
232 
233 }
234 
235 /* Helper function for pnfs_generic_commit_pagelist to catch an empty
236  * page list. This can happen when two commits race.
237  *
238  * This must be called instead of nfs_init_commit - call one or the other, but
239  * not both!
240  */
241 static bool
242 pnfs_generic_commit_cancel_empty_pagelist(struct list_head *pages,
243 					  struct nfs_commit_data *data,
244 					  struct nfs_commit_info *cinfo)
245 {
246 	if (list_empty(pages)) {
247 		if (atomic_dec_and_test(&cinfo->mds->rpcs_out))
248 			wake_up_var(&cinfo->mds->rpcs_out);
249 		/* don't call nfs_commitdata_release - it tries to put
250 		 * the open_context which is not acquired until nfs_init_commit
251 		 * which has not been called on @data */
252 		WARN_ON_ONCE(data->context);
253 		nfs_commit_free(data);
254 		return true;
255 	}
256 
257 	return false;
258 }
259 
260 /* This follows nfs_commit_list pretty closely */
261 int
262 pnfs_generic_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
263 			     int how, struct nfs_commit_info *cinfo,
264 			     int (*initiate_commit)(struct nfs_commit_data *data,
265 						    int how))
266 {
267 	struct nfs_commit_data *data, *tmp;
268 	LIST_HEAD(list);
269 	unsigned int nreq = 0;
270 
271 	if (!list_empty(mds_pages)) {
272 		data = nfs_commitdata_alloc(true);
273 		data->ds_commit_index = -1;
274 		list_add(&data->pages, &list);
275 		nreq++;
276 	}
277 
278 	nreq += pnfs_generic_alloc_ds_commits(cinfo, &list);
279 
280 	if (nreq == 0)
281 		goto out;
282 
283 	atomic_add(nreq, &cinfo->mds->rpcs_out);
284 
285 	list_for_each_entry_safe(data, tmp, &list, pages) {
286 		list_del_init(&data->pages);
287 		if (data->ds_commit_index < 0) {
288 			/* another commit raced with us */
289 			if (pnfs_generic_commit_cancel_empty_pagelist(mds_pages,
290 				data, cinfo))
291 				continue;
292 
293 			nfs_init_commit(data, mds_pages, NULL, cinfo);
294 			nfs_initiate_commit(NFS_CLIENT(inode), data,
295 					    NFS_PROTO(data->inode),
296 					    data->mds_ops, how, 0);
297 		} else {
298 			LIST_HEAD(pages);
299 
300 			pnfs_fetch_commit_bucket_list(&pages, data, cinfo);
301 
302 			/* another commit raced with us */
303 			if (pnfs_generic_commit_cancel_empty_pagelist(&pages,
304 				data, cinfo))
305 				continue;
306 
307 			nfs_init_commit(data, &pages, data->lseg, cinfo);
308 			initiate_commit(data, how);
309 		}
310 	}
311 out:
312 	return PNFS_ATTEMPTED;
313 }
314 EXPORT_SYMBOL_GPL(pnfs_generic_commit_pagelist);
315 
316 /*
317  * Data server cache
318  *
319  * Data servers can be mapped to different device ids.
320  * nfs4_pnfs_ds reference counting
321  *   - set to 1 on allocation
322  *   - incremented when a device id maps a data server already in the cache.
323  *   - decremented when deviceid is removed from the cache.
324  */
325 static DEFINE_SPINLOCK(nfs4_ds_cache_lock);
326 static LIST_HEAD(nfs4_data_server_cache);
327 
328 /* Debug routines */
329 static void
330 print_ds(struct nfs4_pnfs_ds *ds)
331 {
332 	if (ds == NULL) {
333 		printk(KERN_WARNING "%s NULL device\n", __func__);
334 		return;
335 	}
336 	printk(KERN_WARNING "        ds %s\n"
337 		"        ref count %d\n"
338 		"        client %p\n"
339 		"        cl_exchange_flags %x\n",
340 		ds->ds_remotestr,
341 		refcount_read(&ds->ds_count), ds->ds_clp,
342 		ds->ds_clp ? ds->ds_clp->cl_exchange_flags : 0);
343 }
344 
345 static bool
346 same_sockaddr(struct sockaddr *addr1, struct sockaddr *addr2)
347 {
348 	struct sockaddr_in *a, *b;
349 	struct sockaddr_in6 *a6, *b6;
350 
351 	if (addr1->sa_family != addr2->sa_family)
352 		return false;
353 
354 	switch (addr1->sa_family) {
355 	case AF_INET:
356 		a = (struct sockaddr_in *)addr1;
357 		b = (struct sockaddr_in *)addr2;
358 
359 		if (a->sin_addr.s_addr == b->sin_addr.s_addr &&
360 		    a->sin_port == b->sin_port)
361 			return true;
362 		break;
363 
364 	case AF_INET6:
365 		a6 = (struct sockaddr_in6 *)addr1;
366 		b6 = (struct sockaddr_in6 *)addr2;
367 
368 		/* LINKLOCAL addresses must have matching scope_id */
369 		if (ipv6_addr_src_scope(&a6->sin6_addr) ==
370 		    IPV6_ADDR_SCOPE_LINKLOCAL &&
371 		    a6->sin6_scope_id != b6->sin6_scope_id)
372 			return false;
373 
374 		if (ipv6_addr_equal(&a6->sin6_addr, &b6->sin6_addr) &&
375 		    a6->sin6_port == b6->sin6_port)
376 			return true;
377 		break;
378 
379 	default:
380 		dprintk("%s: unhandled address family: %u\n",
381 			__func__, addr1->sa_family);
382 		return false;
383 	}
384 
385 	return false;
386 }
387 
388 /*
389  * Checks if 'dsaddrs1' contains a subset of 'dsaddrs2'. If it does,
390  * declare a match.
391  */
392 static bool
393 _same_data_server_addrs_locked(const struct list_head *dsaddrs1,
394 			       const struct list_head *dsaddrs2)
395 {
396 	struct nfs4_pnfs_ds_addr *da1, *da2;
397 	struct sockaddr *sa1, *sa2;
398 	bool match = false;
399 
400 	list_for_each_entry(da1, dsaddrs1, da_node) {
401 		sa1 = (struct sockaddr *)&da1->da_addr;
402 		match = false;
403 		list_for_each_entry(da2, dsaddrs2, da_node) {
404 			sa2 = (struct sockaddr *)&da2->da_addr;
405 			match = same_sockaddr(sa1, sa2);
406 			if (match)
407 				break;
408 		}
409 		if (!match)
410 			break;
411 	}
412 	return match;
413 }
414 
415 /*
416  * Lookup DS by addresses.  nfs4_ds_cache_lock is held
417  */
418 static struct nfs4_pnfs_ds *
419 _data_server_lookup_locked(const struct list_head *dsaddrs)
420 {
421 	struct nfs4_pnfs_ds *ds;
422 
423 	list_for_each_entry(ds, &nfs4_data_server_cache, ds_node)
424 		if (_same_data_server_addrs_locked(&ds->ds_addrs, dsaddrs))
425 			return ds;
426 	return NULL;
427 }
428 
429 static void destroy_ds(struct nfs4_pnfs_ds *ds)
430 {
431 	struct nfs4_pnfs_ds_addr *da;
432 
433 	dprintk("--> %s\n", __func__);
434 	ifdebug(FACILITY)
435 		print_ds(ds);
436 
437 	nfs_put_client(ds->ds_clp);
438 
439 	while (!list_empty(&ds->ds_addrs)) {
440 		da = list_first_entry(&ds->ds_addrs,
441 				      struct nfs4_pnfs_ds_addr,
442 				      da_node);
443 		list_del_init(&da->da_node);
444 		kfree(da->da_remotestr);
445 		kfree(da);
446 	}
447 
448 	kfree(ds->ds_remotestr);
449 	kfree(ds);
450 }
451 
452 void nfs4_pnfs_ds_put(struct nfs4_pnfs_ds *ds)
453 {
454 	if (refcount_dec_and_lock(&ds->ds_count,
455 				&nfs4_ds_cache_lock)) {
456 		list_del_init(&ds->ds_node);
457 		spin_unlock(&nfs4_ds_cache_lock);
458 		destroy_ds(ds);
459 	}
460 }
461 EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_put);
462 
463 /*
464  * Create a string with a human readable address and port to avoid
465  * complicated setup around many dprinks.
466  */
467 static char *
468 nfs4_pnfs_remotestr(struct list_head *dsaddrs, gfp_t gfp_flags)
469 {
470 	struct nfs4_pnfs_ds_addr *da;
471 	char *remotestr;
472 	size_t len;
473 	char *p;
474 
475 	len = 3;        /* '{', '}' and eol */
476 	list_for_each_entry(da, dsaddrs, da_node) {
477 		len += strlen(da->da_remotestr) + 1;    /* string plus comma */
478 	}
479 
480 	remotestr = kzalloc(len, gfp_flags);
481 	if (!remotestr)
482 		return NULL;
483 
484 	p = remotestr;
485 	*(p++) = '{';
486 	len--;
487 	list_for_each_entry(da, dsaddrs, da_node) {
488 		size_t ll = strlen(da->da_remotestr);
489 
490 		if (ll > len)
491 			goto out_err;
492 
493 		memcpy(p, da->da_remotestr, ll);
494 		p += ll;
495 		len -= ll;
496 
497 		if (len < 1)
498 			goto out_err;
499 		(*p++) = ',';
500 		len--;
501 	}
502 	if (len < 2)
503 		goto out_err;
504 	*(p++) = '}';
505 	*p = '\0';
506 	return remotestr;
507 out_err:
508 	kfree(remotestr);
509 	return NULL;
510 }
511 
512 /*
513  * Given a list of multipath struct nfs4_pnfs_ds_addr, add it to ds cache if
514  * uncached and return cached struct nfs4_pnfs_ds.
515  */
516 struct nfs4_pnfs_ds *
517 nfs4_pnfs_ds_add(struct list_head *dsaddrs, gfp_t gfp_flags)
518 {
519 	struct nfs4_pnfs_ds *tmp_ds, *ds = NULL;
520 	char *remotestr;
521 
522 	if (list_empty(dsaddrs)) {
523 		dprintk("%s: no addresses defined\n", __func__);
524 		goto out;
525 	}
526 
527 	ds = kzalloc(sizeof(*ds), gfp_flags);
528 	if (!ds)
529 		goto out;
530 
531 	/* this is only used for debugging, so it's ok if its NULL */
532 	remotestr = nfs4_pnfs_remotestr(dsaddrs, gfp_flags);
533 
534 	spin_lock(&nfs4_ds_cache_lock);
535 	tmp_ds = _data_server_lookup_locked(dsaddrs);
536 	if (tmp_ds == NULL) {
537 		INIT_LIST_HEAD(&ds->ds_addrs);
538 		list_splice_init(dsaddrs, &ds->ds_addrs);
539 		ds->ds_remotestr = remotestr;
540 		refcount_set(&ds->ds_count, 1);
541 		INIT_LIST_HEAD(&ds->ds_node);
542 		ds->ds_clp = NULL;
543 		list_add(&ds->ds_node, &nfs4_data_server_cache);
544 		dprintk("%s add new data server %s\n", __func__,
545 			ds->ds_remotestr);
546 	} else {
547 		kfree(remotestr);
548 		kfree(ds);
549 		refcount_inc(&tmp_ds->ds_count);
550 		dprintk("%s data server %s found, inc'ed ds_count to %d\n",
551 			__func__, tmp_ds->ds_remotestr,
552 			refcount_read(&tmp_ds->ds_count));
553 		ds = tmp_ds;
554 	}
555 	spin_unlock(&nfs4_ds_cache_lock);
556 out:
557 	return ds;
558 }
559 EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_add);
560 
561 static void nfs4_wait_ds_connect(struct nfs4_pnfs_ds *ds)
562 {
563 	might_sleep();
564 	wait_on_bit(&ds->ds_state, NFS4DS_CONNECTING,
565 			TASK_KILLABLE);
566 }
567 
568 static void nfs4_clear_ds_conn_bit(struct nfs4_pnfs_ds *ds)
569 {
570 	smp_mb__before_atomic();
571 	clear_bit(NFS4DS_CONNECTING, &ds->ds_state);
572 	smp_mb__after_atomic();
573 	wake_up_bit(&ds->ds_state, NFS4DS_CONNECTING);
574 }
575 
576 static struct nfs_client *(*get_v3_ds_connect)(
577 			struct nfs_server *mds_srv,
578 			const struct sockaddr *ds_addr,
579 			int ds_addrlen,
580 			int ds_proto,
581 			unsigned int ds_timeo,
582 			unsigned int ds_retrans);
583 
584 static bool load_v3_ds_connect(void)
585 {
586 	if (!get_v3_ds_connect) {
587 		get_v3_ds_connect = symbol_request(nfs3_set_ds_client);
588 		WARN_ON_ONCE(!get_v3_ds_connect);
589 	}
590 
591 	return(get_v3_ds_connect != NULL);
592 }
593 
594 void nfs4_pnfs_v3_ds_connect_unload(void)
595 {
596 	if (get_v3_ds_connect) {
597 		symbol_put(nfs3_set_ds_client);
598 		get_v3_ds_connect = NULL;
599 	}
600 }
601 
602 static int _nfs4_pnfs_v3_ds_connect(struct nfs_server *mds_srv,
603 				 struct nfs4_pnfs_ds *ds,
604 				 unsigned int timeo,
605 				 unsigned int retrans)
606 {
607 	struct nfs_client *clp = ERR_PTR(-EIO);
608 	struct nfs4_pnfs_ds_addr *da;
609 	int status = 0;
610 
611 	dprintk("--> %s DS %s\n", __func__, ds->ds_remotestr);
612 
613 	if (!load_v3_ds_connect())
614 		goto out;
615 
616 	list_for_each_entry(da, &ds->ds_addrs, da_node) {
617 		dprintk("%s: DS %s: trying address %s\n",
618 			__func__, ds->ds_remotestr, da->da_remotestr);
619 
620 		if (!IS_ERR(clp)) {
621 			struct xprt_create xprt_args = {
622 				.ident = XPRT_TRANSPORT_TCP,
623 				.net = clp->cl_net,
624 				.dstaddr = (struct sockaddr *)&da->da_addr,
625 				.addrlen = da->da_addrlen,
626 				.servername = clp->cl_hostname,
627 			};
628 			/* Add this address as an alias */
629 			rpc_clnt_add_xprt(clp->cl_rpcclient, &xprt_args,
630 					rpc_clnt_test_and_add_xprt, NULL);
631 		} else
632 			clp = get_v3_ds_connect(mds_srv,
633 					(struct sockaddr *)&da->da_addr,
634 					da->da_addrlen, IPPROTO_TCP,
635 					timeo, retrans);
636 	}
637 
638 	if (IS_ERR(clp)) {
639 		status = PTR_ERR(clp);
640 		goto out;
641 	}
642 
643 	smp_wmb();
644 	ds->ds_clp = clp;
645 	dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr);
646 out:
647 	return status;
648 }
649 
650 static int _nfs4_pnfs_v4_ds_connect(struct nfs_server *mds_srv,
651 				 struct nfs4_pnfs_ds *ds,
652 				 unsigned int timeo,
653 				 unsigned int retrans,
654 				 u32 minor_version)
655 {
656 	struct nfs_client *clp = ERR_PTR(-EIO);
657 	struct nfs4_pnfs_ds_addr *da;
658 	int status = 0;
659 
660 	dprintk("--> %s DS %s\n", __func__, ds->ds_remotestr);
661 
662 	list_for_each_entry(da, &ds->ds_addrs, da_node) {
663 		dprintk("%s: DS %s: trying address %s\n",
664 			__func__, ds->ds_remotestr, da->da_remotestr);
665 
666 		if (!IS_ERR(clp) && clp->cl_mvops->session_trunk) {
667 			struct xprt_create xprt_args = {
668 				.ident = XPRT_TRANSPORT_TCP,
669 				.net = clp->cl_net,
670 				.dstaddr = (struct sockaddr *)&da->da_addr,
671 				.addrlen = da->da_addrlen,
672 				.servername = clp->cl_hostname,
673 			};
674 			struct nfs4_add_xprt_data xprtdata = {
675 				.clp = clp,
676 				.cred = nfs4_get_clid_cred(clp),
677 			};
678 			struct rpc_add_xprt_test rpcdata = {
679 				.add_xprt_test = clp->cl_mvops->session_trunk,
680 				.data = &xprtdata,
681 			};
682 
683 			/**
684 			* Test this address for session trunking and
685 			* add as an alias
686 			*/
687 			rpc_clnt_add_xprt(clp->cl_rpcclient, &xprt_args,
688 					  rpc_clnt_setup_test_and_add_xprt,
689 					  &rpcdata);
690 			if (xprtdata.cred)
691 				put_rpccred(xprtdata.cred);
692 		} else {
693 			clp = nfs4_set_ds_client(mds_srv,
694 						(struct sockaddr *)&da->da_addr,
695 						da->da_addrlen, IPPROTO_TCP,
696 						timeo, retrans, minor_version);
697 			if (IS_ERR(clp))
698 				continue;
699 
700 			status = nfs4_init_ds_session(clp,
701 					mds_srv->nfs_client->cl_lease_time);
702 			if (status) {
703 				nfs_put_client(clp);
704 				clp = ERR_PTR(-EIO);
705 				continue;
706 			}
707 
708 		}
709 	}
710 
711 	if (IS_ERR(clp)) {
712 		status = PTR_ERR(clp);
713 		goto out;
714 	}
715 
716 	smp_wmb();
717 	ds->ds_clp = clp;
718 	dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr);
719 out:
720 	return status;
721 }
722 
723 /*
724  * Create an rpc connection to the nfs4_pnfs_ds data server.
725  * Currently only supports IPv4 and IPv6 addresses.
726  * If connection fails, make devid unavailable and return a -errno.
727  */
728 int nfs4_pnfs_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds,
729 			  struct nfs4_deviceid_node *devid, unsigned int timeo,
730 			  unsigned int retrans, u32 version, u32 minor_version)
731 {
732 	int err;
733 
734 again:
735 	err = 0;
736 	if (test_and_set_bit(NFS4DS_CONNECTING, &ds->ds_state) == 0) {
737 		if (version == 3) {
738 			err = _nfs4_pnfs_v3_ds_connect(mds_srv, ds, timeo,
739 						       retrans);
740 		} else if (version == 4) {
741 			err = _nfs4_pnfs_v4_ds_connect(mds_srv, ds, timeo,
742 						       retrans, minor_version);
743 		} else {
744 			dprintk("%s: unsupported DS version %d\n", __func__,
745 				version);
746 			err = -EPROTONOSUPPORT;
747 		}
748 
749 		nfs4_clear_ds_conn_bit(ds);
750 	} else {
751 		nfs4_wait_ds_connect(ds);
752 
753 		/* what was waited on didn't connect AND didn't mark unavail */
754 		if (!ds->ds_clp && !nfs4_test_deviceid_unavailable(devid))
755 			goto again;
756 	}
757 
758 	/*
759 	 * At this point the ds->ds_clp should be ready, but it might have
760 	 * hit an error.
761 	 */
762 	if (!err) {
763 		if (!ds->ds_clp || !nfs_client_init_is_complete(ds->ds_clp)) {
764 			WARN_ON_ONCE(ds->ds_clp ||
765 				!nfs4_test_deviceid_unavailable(devid));
766 			return -EINVAL;
767 		}
768 		err = nfs_client_init_status(ds->ds_clp);
769 	}
770 
771 	return err;
772 }
773 EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_connect);
774 
775 /*
776  * Currently only supports ipv4, ipv6 and one multi-path address.
777  */
778 struct nfs4_pnfs_ds_addr *
779 nfs4_decode_mp_ds_addr(struct net *net, struct xdr_stream *xdr, gfp_t gfp_flags)
780 {
781 	struct nfs4_pnfs_ds_addr *da = NULL;
782 	char *buf, *portstr;
783 	__be16 port;
784 	int nlen, rlen;
785 	int tmp[2];
786 	__be32 *p;
787 	char *netid, *match_netid;
788 	size_t len, match_netid_len;
789 	char *startsep = "";
790 	char *endsep = "";
791 
792 
793 	/* r_netid */
794 	p = xdr_inline_decode(xdr, 4);
795 	if (unlikely(!p))
796 		goto out_err;
797 	nlen = be32_to_cpup(p++);
798 
799 	p = xdr_inline_decode(xdr, nlen);
800 	if (unlikely(!p))
801 		goto out_err;
802 
803 	netid = kmalloc(nlen+1, gfp_flags);
804 	if (unlikely(!netid))
805 		goto out_err;
806 
807 	netid[nlen] = '\0';
808 	memcpy(netid, p, nlen);
809 
810 	/* r_addr: ip/ip6addr with port in dec octets - see RFC 5665 */
811 	p = xdr_inline_decode(xdr, 4);
812 	if (unlikely(!p))
813 		goto out_free_netid;
814 	rlen = be32_to_cpup(p);
815 
816 	p = xdr_inline_decode(xdr, rlen);
817 	if (unlikely(!p))
818 		goto out_free_netid;
819 
820 	/* port is ".ABC.DEF", 8 chars max */
821 	if (rlen > INET6_ADDRSTRLEN + IPV6_SCOPE_ID_LEN + 8) {
822 		dprintk("%s: Invalid address, length %d\n", __func__,
823 			rlen);
824 		goto out_free_netid;
825 	}
826 	buf = kmalloc(rlen + 1, gfp_flags);
827 	if (!buf) {
828 		dprintk("%s: Not enough memory\n", __func__);
829 		goto out_free_netid;
830 	}
831 	buf[rlen] = '\0';
832 	memcpy(buf, p, rlen);
833 
834 	/* replace port '.' with '-' */
835 	portstr = strrchr(buf, '.');
836 	if (!portstr) {
837 		dprintk("%s: Failed finding expected dot in port\n",
838 			__func__);
839 		goto out_free_buf;
840 	}
841 	*portstr = '-';
842 
843 	/* find '.' between address and port */
844 	portstr = strrchr(buf, '.');
845 	if (!portstr) {
846 		dprintk("%s: Failed finding expected dot between address and "
847 			"port\n", __func__);
848 		goto out_free_buf;
849 	}
850 	*portstr = '\0';
851 
852 	da = kzalloc(sizeof(*da), gfp_flags);
853 	if (unlikely(!da))
854 		goto out_free_buf;
855 
856 	INIT_LIST_HEAD(&da->da_node);
857 
858 	if (!rpc_pton(net, buf, portstr-buf, (struct sockaddr *)&da->da_addr,
859 		      sizeof(da->da_addr))) {
860 		dprintk("%s: error parsing address %s\n", __func__, buf);
861 		goto out_free_da;
862 	}
863 
864 	portstr++;
865 	sscanf(portstr, "%d-%d", &tmp[0], &tmp[1]);
866 	port = htons((tmp[0] << 8) | (tmp[1]));
867 
868 	switch (da->da_addr.ss_family) {
869 	case AF_INET:
870 		((struct sockaddr_in *)&da->da_addr)->sin_port = port;
871 		da->da_addrlen = sizeof(struct sockaddr_in);
872 		match_netid = "tcp";
873 		match_netid_len = 3;
874 		break;
875 
876 	case AF_INET6:
877 		((struct sockaddr_in6 *)&da->da_addr)->sin6_port = port;
878 		da->da_addrlen = sizeof(struct sockaddr_in6);
879 		match_netid = "tcp6";
880 		match_netid_len = 4;
881 		startsep = "[";
882 		endsep = "]";
883 		break;
884 
885 	default:
886 		dprintk("%s: unsupported address family: %u\n",
887 			__func__, da->da_addr.ss_family);
888 		goto out_free_da;
889 	}
890 
891 	if (nlen != match_netid_len || strncmp(netid, match_netid, nlen)) {
892 		dprintk("%s: ERROR: r_netid \"%s\" != \"%s\"\n",
893 			__func__, netid, match_netid);
894 		goto out_free_da;
895 	}
896 
897 	/* save human readable address */
898 	len = strlen(startsep) + strlen(buf) + strlen(endsep) + 7;
899 	da->da_remotestr = kzalloc(len, gfp_flags);
900 
901 	/* NULL is ok, only used for dprintk */
902 	if (da->da_remotestr)
903 		snprintf(da->da_remotestr, len, "%s%s%s:%u", startsep,
904 			 buf, endsep, ntohs(port));
905 
906 	dprintk("%s: Parsed DS addr %s\n", __func__, da->da_remotestr);
907 	kfree(buf);
908 	kfree(netid);
909 	return da;
910 
911 out_free_da:
912 	kfree(da);
913 out_free_buf:
914 	dprintk("%s: Error parsing DS addr: %s\n", __func__, buf);
915 	kfree(buf);
916 out_free_netid:
917 	kfree(netid);
918 out_err:
919 	return NULL;
920 }
921 EXPORT_SYMBOL_GPL(nfs4_decode_mp_ds_addr);
922 
923 void
924 pnfs_layout_mark_request_commit(struct nfs_page *req,
925 				struct pnfs_layout_segment *lseg,
926 				struct nfs_commit_info *cinfo,
927 				u32 ds_commit_idx)
928 {
929 	struct list_head *list;
930 	struct pnfs_commit_bucket *buckets;
931 
932 	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
933 	buckets = cinfo->ds->buckets;
934 	list = &buckets[ds_commit_idx].written;
935 	if (list_empty(list)) {
936 		if (!pnfs_is_valid_lseg(lseg)) {
937 			mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
938 			cinfo->completion_ops->resched_write(cinfo, req);
939 			return;
940 		}
941 		/* Non-empty buckets hold a reference on the lseg.  That ref
942 		 * is normally transferred to the COMMIT call and released
943 		 * there.  It could also be released if the last req is pulled
944 		 * off due to a rewrite, in which case it will be done in
945 		 * pnfs_common_clear_request_commit
946 		 */
947 		WARN_ON_ONCE(buckets[ds_commit_idx].wlseg != NULL);
948 		buckets[ds_commit_idx].wlseg = pnfs_get_lseg(lseg);
949 	}
950 	set_bit(PG_COMMIT_TO_DS, &req->wb_flags);
951 	cinfo->ds->nwritten++;
952 
953 	nfs_request_add_commit_list_locked(req, list, cinfo);
954 	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
955 	nfs_mark_page_unstable(req->wb_page, cinfo);
956 }
957 EXPORT_SYMBOL_GPL(pnfs_layout_mark_request_commit);
958 
959 int
960 pnfs_nfs_generic_sync(struct inode *inode, bool datasync)
961 {
962 	int ret;
963 
964 	if (!pnfs_layoutcommit_outstanding(inode))
965 		return 0;
966 	ret = nfs_commit_inode(inode, FLUSH_SYNC);
967 	if (ret < 0)
968 		return ret;
969 	if (datasync)
970 		return 0;
971 	return pnfs_layoutcommit_inode(inode, true);
972 }
973 EXPORT_SYMBOL_GPL(pnfs_nfs_generic_sync);
974 
975