1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Module for pnfs flexfile layout driver.
4  *
5  * Copyright (c) 2014, Primary Data, Inc. All rights reserved.
6  *
7  * Tao Peng <bergwolf@primarydata.com>
8  */
9 
10 #include <linux/nfs_fs.h>
11 #include <linux/nfs_mount.h>
12 #include <linux/nfs_page.h>
13 #include <linux/module.h>
14 #include <linux/sched/mm.h>
15 
16 #include <linux/sunrpc/metrics.h>
17 
18 #include "flexfilelayout.h"
19 #include "../nfs4session.h"
20 #include "../nfs4idmap.h"
21 #include "../internal.h"
22 #include "../delegation.h"
23 #include "../nfs4trace.h"
24 #include "../iostat.h"
25 #include "../nfs.h"
26 #include "../nfs42.h"
27 
28 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
29 
30 #define FF_LAYOUT_POLL_RETRY_MAX     (15*HZ)
31 #define FF_LAYOUTRETURN_MAXERR 20
32 
33 static unsigned short io_maxretrans;
34 
35 static const struct pnfs_commit_ops ff_layout_commit_ops;
36 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
37 		struct nfs_pgio_header *hdr);
38 static int ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
39 			       struct nfs42_layoutstat_devinfo *devinfo,
40 			       int dev_limit);
41 static void ff_layout_encode_ff_layoutupdate(struct xdr_stream *xdr,
42 			      const struct nfs42_layoutstat_devinfo *devinfo,
43 			      struct nfs4_ff_layout_mirror *mirror);
44 
45 static struct pnfs_layout_hdr *
46 ff_layout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags)
47 {
48 	struct nfs4_flexfile_layout *ffl;
49 
50 	ffl = kzalloc(sizeof(*ffl), gfp_flags);
51 	if (ffl) {
52 		pnfs_init_ds_commit_info(&ffl->commit_info);
53 		INIT_LIST_HEAD(&ffl->error_list);
54 		INIT_LIST_HEAD(&ffl->mirrors);
55 		ffl->last_report_time = ktime_get();
56 		ffl->commit_info.ops = &ff_layout_commit_ops;
57 		return &ffl->generic_hdr;
58 	} else
59 		return NULL;
60 }
61 
62 static void
63 ff_layout_free_layout_hdr(struct pnfs_layout_hdr *lo)
64 {
65 	struct nfs4_flexfile_layout *ffl = FF_LAYOUT_FROM_HDR(lo);
66 	struct nfs4_ff_layout_ds_err *err, *n;
67 
68 	list_for_each_entry_safe(err, n, &ffl->error_list, list) {
69 		list_del(&err->list);
70 		kfree(err);
71 	}
72 	kfree_rcu(ffl, generic_hdr.plh_rcu);
73 }
74 
75 static int decode_pnfs_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
76 {
77 	__be32 *p;
78 
79 	p = xdr_inline_decode(xdr, NFS4_STATEID_SIZE);
80 	if (unlikely(p == NULL))
81 		return -ENOBUFS;
82 	stateid->type = NFS4_PNFS_DS_STATEID_TYPE;
83 	memcpy(stateid->data, p, NFS4_STATEID_SIZE);
84 	dprintk("%s: stateid id= [%x%x%x%x]\n", __func__,
85 		p[0], p[1], p[2], p[3]);
86 	return 0;
87 }
88 
89 static int decode_deviceid(struct xdr_stream *xdr, struct nfs4_deviceid *devid)
90 {
91 	__be32 *p;
92 
93 	p = xdr_inline_decode(xdr, NFS4_DEVICEID4_SIZE);
94 	if (unlikely(!p))
95 		return -ENOBUFS;
96 	memcpy(devid, p, NFS4_DEVICEID4_SIZE);
97 	nfs4_print_deviceid(devid);
98 	return 0;
99 }
100 
101 static int decode_nfs_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
102 {
103 	__be32 *p;
104 
105 	p = xdr_inline_decode(xdr, 4);
106 	if (unlikely(!p))
107 		return -ENOBUFS;
108 	fh->size = be32_to_cpup(p++);
109 	if (fh->size > sizeof(struct nfs_fh)) {
110 		printk(KERN_ERR "NFS flexfiles: Too big fh received %d\n",
111 		       fh->size);
112 		return -EOVERFLOW;
113 	}
114 	/* fh.data */
115 	p = xdr_inline_decode(xdr, fh->size);
116 	if (unlikely(!p))
117 		return -ENOBUFS;
118 	memcpy(&fh->data, p, fh->size);
119 	dprintk("%s: fh len %d\n", __func__, fh->size);
120 
121 	return 0;
122 }
123 
124 /*
125  * Currently only stringified uids and gids are accepted.
126  * I.e., kerberos is not supported to the DSes, so no pricipals.
127  *
128  * That means that one common function will suffice, but when
129  * principals are added, this should be split to accomodate
130  * calls to both nfs_map_name_to_uid() and nfs_map_group_to_gid().
131  */
132 static int
133 decode_name(struct xdr_stream *xdr, u32 *id)
134 {
135 	__be32 *p;
136 	int len;
137 
138 	/* opaque_length(4)*/
139 	p = xdr_inline_decode(xdr, 4);
140 	if (unlikely(!p))
141 		return -ENOBUFS;
142 	len = be32_to_cpup(p++);
143 	if (len < 0)
144 		return -EINVAL;
145 
146 	dprintk("%s: len %u\n", __func__, len);
147 
148 	/* opaque body */
149 	p = xdr_inline_decode(xdr, len);
150 	if (unlikely(!p))
151 		return -ENOBUFS;
152 
153 	if (!nfs_map_string_to_numeric((char *)p, len, id))
154 		return -EINVAL;
155 
156 	return 0;
157 }
158 
159 static bool ff_mirror_match_fh(const struct nfs4_ff_layout_mirror *m1,
160 		const struct nfs4_ff_layout_mirror *m2)
161 {
162 	int i, j;
163 
164 	if (m1->fh_versions_cnt != m2->fh_versions_cnt)
165 		return false;
166 	for (i = 0; i < m1->fh_versions_cnt; i++) {
167 		bool found_fh = false;
168 		for (j = 0; j < m2->fh_versions_cnt; j++) {
169 			if (nfs_compare_fh(&m1->fh_versions[i],
170 					&m2->fh_versions[j]) == 0) {
171 				found_fh = true;
172 				break;
173 			}
174 		}
175 		if (!found_fh)
176 			return false;
177 	}
178 	return true;
179 }
180 
181 static struct nfs4_ff_layout_mirror *
182 ff_layout_add_mirror(struct pnfs_layout_hdr *lo,
183 		struct nfs4_ff_layout_mirror *mirror)
184 {
185 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
186 	struct nfs4_ff_layout_mirror *pos;
187 	struct inode *inode = lo->plh_inode;
188 
189 	spin_lock(&inode->i_lock);
190 	list_for_each_entry(pos, &ff_layout->mirrors, mirrors) {
191 		if (memcmp(&mirror->devid, &pos->devid, sizeof(pos->devid)) != 0)
192 			continue;
193 		if (!ff_mirror_match_fh(mirror, pos))
194 			continue;
195 		if (refcount_inc_not_zero(&pos->ref)) {
196 			spin_unlock(&inode->i_lock);
197 			return pos;
198 		}
199 	}
200 	list_add(&mirror->mirrors, &ff_layout->mirrors);
201 	mirror->layout = lo;
202 	spin_unlock(&inode->i_lock);
203 	return mirror;
204 }
205 
206 static void
207 ff_layout_remove_mirror(struct nfs4_ff_layout_mirror *mirror)
208 {
209 	struct inode *inode;
210 	if (mirror->layout == NULL)
211 		return;
212 	inode = mirror->layout->plh_inode;
213 	spin_lock(&inode->i_lock);
214 	list_del(&mirror->mirrors);
215 	spin_unlock(&inode->i_lock);
216 	mirror->layout = NULL;
217 }
218 
219 static struct nfs4_ff_layout_mirror *ff_layout_alloc_mirror(gfp_t gfp_flags)
220 {
221 	struct nfs4_ff_layout_mirror *mirror;
222 
223 	mirror = kzalloc(sizeof(*mirror), gfp_flags);
224 	if (mirror != NULL) {
225 		spin_lock_init(&mirror->lock);
226 		refcount_set(&mirror->ref, 1);
227 		INIT_LIST_HEAD(&mirror->mirrors);
228 	}
229 	return mirror;
230 }
231 
232 static void ff_layout_free_mirror(struct nfs4_ff_layout_mirror *mirror)
233 {
234 	const struct cred	*cred;
235 
236 	ff_layout_remove_mirror(mirror);
237 	kfree(mirror->fh_versions);
238 	cred = rcu_access_pointer(mirror->ro_cred);
239 	put_cred(cred);
240 	cred = rcu_access_pointer(mirror->rw_cred);
241 	put_cred(cred);
242 	nfs4_ff_layout_put_deviceid(mirror->mirror_ds);
243 	kfree(mirror);
244 }
245 
246 static void ff_layout_put_mirror(struct nfs4_ff_layout_mirror *mirror)
247 {
248 	if (mirror != NULL && refcount_dec_and_test(&mirror->ref))
249 		ff_layout_free_mirror(mirror);
250 }
251 
252 static void ff_layout_free_mirror_array(struct nfs4_ff_layout_segment *fls)
253 {
254 	u32 i;
255 
256 	for (i = 0; i < fls->mirror_array_cnt; i++)
257 		ff_layout_put_mirror(fls->mirror_array[i]);
258 }
259 
260 static void _ff_layout_free_lseg(struct nfs4_ff_layout_segment *fls)
261 {
262 	if (fls) {
263 		ff_layout_free_mirror_array(fls);
264 		kfree(fls);
265 	}
266 }
267 
268 static bool
269 ff_lseg_match_mirrors(struct pnfs_layout_segment *l1,
270 		struct pnfs_layout_segment *l2)
271 {
272 	const struct nfs4_ff_layout_segment *fl1 = FF_LAYOUT_LSEG(l1);
273 	const struct nfs4_ff_layout_segment *fl2 = FF_LAYOUT_LSEG(l1);
274 	u32 i;
275 
276 	if (fl1->mirror_array_cnt != fl2->mirror_array_cnt)
277 		return false;
278 	for (i = 0; i < fl1->mirror_array_cnt; i++) {
279 		if (fl1->mirror_array[i] != fl2->mirror_array[i])
280 			return false;
281 	}
282 	return true;
283 }
284 
285 static bool
286 ff_lseg_range_is_after(const struct pnfs_layout_range *l1,
287 		const struct pnfs_layout_range *l2)
288 {
289 	u64 end1, end2;
290 
291 	if (l1->iomode != l2->iomode)
292 		return l1->iomode != IOMODE_READ;
293 	end1 = pnfs_calc_offset_end(l1->offset, l1->length);
294 	end2 = pnfs_calc_offset_end(l2->offset, l2->length);
295 	if (end1 < l2->offset)
296 		return false;
297 	if (end2 < l1->offset)
298 		return true;
299 	return l2->offset <= l1->offset;
300 }
301 
302 static bool
303 ff_lseg_merge(struct pnfs_layout_segment *new,
304 		struct pnfs_layout_segment *old)
305 {
306 	u64 new_end, old_end;
307 
308 	if (test_bit(NFS_LSEG_LAYOUTRETURN, &old->pls_flags))
309 		return false;
310 	if (new->pls_range.iomode != old->pls_range.iomode)
311 		return false;
312 	old_end = pnfs_calc_offset_end(old->pls_range.offset,
313 			old->pls_range.length);
314 	if (old_end < new->pls_range.offset)
315 		return false;
316 	new_end = pnfs_calc_offset_end(new->pls_range.offset,
317 			new->pls_range.length);
318 	if (new_end < old->pls_range.offset)
319 		return false;
320 	if (!ff_lseg_match_mirrors(new, old))
321 		return false;
322 
323 	/* Mergeable: copy info from 'old' to 'new' */
324 	if (new_end < old_end)
325 		new_end = old_end;
326 	if (new->pls_range.offset < old->pls_range.offset)
327 		new->pls_range.offset = old->pls_range.offset;
328 	new->pls_range.length = pnfs_calc_offset_length(new->pls_range.offset,
329 			new_end);
330 	if (test_bit(NFS_LSEG_ROC, &old->pls_flags))
331 		set_bit(NFS_LSEG_ROC, &new->pls_flags);
332 	return true;
333 }
334 
335 static void
336 ff_layout_add_lseg(struct pnfs_layout_hdr *lo,
337 		struct pnfs_layout_segment *lseg,
338 		struct list_head *free_me)
339 {
340 	pnfs_generic_layout_insert_lseg(lo, lseg,
341 			ff_lseg_range_is_after,
342 			ff_lseg_merge,
343 			free_me);
344 }
345 
346 static void ff_layout_sort_mirrors(struct nfs4_ff_layout_segment *fls)
347 {
348 	int i, j;
349 
350 	for (i = 0; i < fls->mirror_array_cnt - 1; i++) {
351 		for (j = i + 1; j < fls->mirror_array_cnt; j++)
352 			if (fls->mirror_array[i]->efficiency <
353 			    fls->mirror_array[j]->efficiency)
354 				swap(fls->mirror_array[i],
355 				     fls->mirror_array[j]);
356 	}
357 }
358 
359 static struct pnfs_layout_segment *
360 ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh,
361 		     struct nfs4_layoutget_res *lgr,
362 		     gfp_t gfp_flags)
363 {
364 	struct pnfs_layout_segment *ret;
365 	struct nfs4_ff_layout_segment *fls = NULL;
366 	struct xdr_stream stream;
367 	struct xdr_buf buf;
368 	struct page *scratch;
369 	u64 stripe_unit;
370 	u32 mirror_array_cnt;
371 	__be32 *p;
372 	int i, rc;
373 
374 	dprintk("--> %s\n", __func__);
375 	scratch = alloc_page(gfp_flags);
376 	if (!scratch)
377 		return ERR_PTR(-ENOMEM);
378 
379 	xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages,
380 			      lgr->layoutp->len);
381 	xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
382 
383 	/* stripe unit and mirror_array_cnt */
384 	rc = -EIO;
385 	p = xdr_inline_decode(&stream, 8 + 4);
386 	if (!p)
387 		goto out_err_free;
388 
389 	p = xdr_decode_hyper(p, &stripe_unit);
390 	mirror_array_cnt = be32_to_cpup(p++);
391 	dprintk("%s: stripe_unit=%llu mirror_array_cnt=%u\n", __func__,
392 		stripe_unit, mirror_array_cnt);
393 
394 	if (mirror_array_cnt > NFS4_FLEXFILE_LAYOUT_MAX_MIRROR_CNT ||
395 	    mirror_array_cnt == 0)
396 		goto out_err_free;
397 
398 	rc = -ENOMEM;
399 	fls = kzalloc(struct_size(fls, mirror_array, mirror_array_cnt),
400 			gfp_flags);
401 	if (!fls)
402 		goto out_err_free;
403 
404 	fls->mirror_array_cnt = mirror_array_cnt;
405 	fls->stripe_unit = stripe_unit;
406 
407 	for (i = 0; i < fls->mirror_array_cnt; i++) {
408 		struct nfs4_ff_layout_mirror *mirror;
409 		struct cred *kcred;
410 		const struct cred __rcu *cred;
411 		kuid_t uid;
412 		kgid_t gid;
413 		u32 ds_count, fh_count, id;
414 		int j;
415 
416 		rc = -EIO;
417 		p = xdr_inline_decode(&stream, 4);
418 		if (!p)
419 			goto out_err_free;
420 		ds_count = be32_to_cpup(p);
421 
422 		/* FIXME: allow for striping? */
423 		if (ds_count != 1)
424 			goto out_err_free;
425 
426 		fls->mirror_array[i] = ff_layout_alloc_mirror(gfp_flags);
427 		if (fls->mirror_array[i] == NULL) {
428 			rc = -ENOMEM;
429 			goto out_err_free;
430 		}
431 
432 		fls->mirror_array[i]->ds_count = ds_count;
433 
434 		/* deviceid */
435 		rc = decode_deviceid(&stream, &fls->mirror_array[i]->devid);
436 		if (rc)
437 			goto out_err_free;
438 
439 		/* efficiency */
440 		rc = -EIO;
441 		p = xdr_inline_decode(&stream, 4);
442 		if (!p)
443 			goto out_err_free;
444 		fls->mirror_array[i]->efficiency = be32_to_cpup(p);
445 
446 		/* stateid */
447 		rc = decode_pnfs_stateid(&stream, &fls->mirror_array[i]->stateid);
448 		if (rc)
449 			goto out_err_free;
450 
451 		/* fh */
452 		rc = -EIO;
453 		p = xdr_inline_decode(&stream, 4);
454 		if (!p)
455 			goto out_err_free;
456 		fh_count = be32_to_cpup(p);
457 
458 		fls->mirror_array[i]->fh_versions =
459 			kcalloc(fh_count, sizeof(struct nfs_fh),
460 				gfp_flags);
461 		if (fls->mirror_array[i]->fh_versions == NULL) {
462 			rc = -ENOMEM;
463 			goto out_err_free;
464 		}
465 
466 		for (j = 0; j < fh_count; j++) {
467 			rc = decode_nfs_fh(&stream,
468 					   &fls->mirror_array[i]->fh_versions[j]);
469 			if (rc)
470 				goto out_err_free;
471 		}
472 
473 		fls->mirror_array[i]->fh_versions_cnt = fh_count;
474 
475 		/* user */
476 		rc = decode_name(&stream, &id);
477 		if (rc)
478 			goto out_err_free;
479 
480 		uid = make_kuid(&init_user_ns, id);
481 
482 		/* group */
483 		rc = decode_name(&stream, &id);
484 		if (rc)
485 			goto out_err_free;
486 
487 		gid = make_kgid(&init_user_ns, id);
488 
489 		if (gfp_flags & __GFP_FS)
490 			kcred = prepare_kernel_cred(NULL);
491 		else {
492 			unsigned int nofs_flags = memalloc_nofs_save();
493 			kcred = prepare_kernel_cred(NULL);
494 			memalloc_nofs_restore(nofs_flags);
495 		}
496 		rc = -ENOMEM;
497 		if (!kcred)
498 			goto out_err_free;
499 		kcred->fsuid = uid;
500 		kcred->fsgid = gid;
501 		cred = RCU_INITIALIZER(kcred);
502 
503 		if (lgr->range.iomode == IOMODE_READ)
504 			rcu_assign_pointer(fls->mirror_array[i]->ro_cred, cred);
505 		else
506 			rcu_assign_pointer(fls->mirror_array[i]->rw_cred, cred);
507 
508 		mirror = ff_layout_add_mirror(lh, fls->mirror_array[i]);
509 		if (mirror != fls->mirror_array[i]) {
510 			/* swap cred ptrs so free_mirror will clean up old */
511 			if (lgr->range.iomode == IOMODE_READ) {
512 				cred = xchg(&mirror->ro_cred, cred);
513 				rcu_assign_pointer(fls->mirror_array[i]->ro_cred, cred);
514 			} else {
515 				cred = xchg(&mirror->rw_cred, cred);
516 				rcu_assign_pointer(fls->mirror_array[i]->rw_cred, cred);
517 			}
518 			ff_layout_free_mirror(fls->mirror_array[i]);
519 			fls->mirror_array[i] = mirror;
520 		}
521 
522 		dprintk("%s: iomode %s uid %u gid %u\n", __func__,
523 			lgr->range.iomode == IOMODE_READ ? "READ" : "RW",
524 			from_kuid(&init_user_ns, uid),
525 			from_kgid(&init_user_ns, gid));
526 	}
527 
528 	p = xdr_inline_decode(&stream, 4);
529 	if (!p)
530 		goto out_sort_mirrors;
531 	fls->flags = be32_to_cpup(p);
532 
533 	p = xdr_inline_decode(&stream, 4);
534 	if (!p)
535 		goto out_sort_mirrors;
536 	for (i=0; i < fls->mirror_array_cnt; i++)
537 		fls->mirror_array[i]->report_interval = be32_to_cpup(p);
538 
539 out_sort_mirrors:
540 	ff_layout_sort_mirrors(fls);
541 	ret = &fls->generic_hdr;
542 	dprintk("<-- %s (success)\n", __func__);
543 out_free_page:
544 	__free_page(scratch);
545 	return ret;
546 out_err_free:
547 	_ff_layout_free_lseg(fls);
548 	ret = ERR_PTR(rc);
549 	dprintk("<-- %s (%d)\n", __func__, rc);
550 	goto out_free_page;
551 }
552 
553 static void
554 ff_layout_free_lseg(struct pnfs_layout_segment *lseg)
555 {
556 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
557 
558 	dprintk("--> %s\n", __func__);
559 
560 	if (lseg->pls_range.iomode == IOMODE_RW) {
561 		struct nfs4_flexfile_layout *ffl;
562 		struct inode *inode;
563 
564 		ffl = FF_LAYOUT_FROM_HDR(lseg->pls_layout);
565 		inode = ffl->generic_hdr.plh_inode;
566 		spin_lock(&inode->i_lock);
567 		pnfs_generic_ds_cinfo_release_lseg(&ffl->commit_info, lseg);
568 		spin_unlock(&inode->i_lock);
569 	}
570 	_ff_layout_free_lseg(fls);
571 }
572 
573 static void
574 nfs4_ff_start_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
575 {
576 	/* first IO request? */
577 	if (atomic_inc_return(&timer->n_ops) == 1) {
578 		timer->start_time = now;
579 	}
580 }
581 
582 static ktime_t
583 nfs4_ff_end_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
584 {
585 	ktime_t start;
586 
587 	if (atomic_dec_return(&timer->n_ops) < 0)
588 		WARN_ON_ONCE(1);
589 
590 	start = timer->start_time;
591 	timer->start_time = now;
592 	return ktime_sub(now, start);
593 }
594 
595 static bool
596 nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_mirror *mirror,
597 			    struct nfs4_ff_layoutstat *layoutstat,
598 			    ktime_t now)
599 {
600 	s64 report_interval = FF_LAYOUTSTATS_REPORT_INTERVAL;
601 	struct nfs4_flexfile_layout *ffl = FF_LAYOUT_FROM_HDR(mirror->layout);
602 
603 	nfs4_ff_start_busy_timer(&layoutstat->busy_timer, now);
604 	if (!mirror->start_time)
605 		mirror->start_time = now;
606 	if (mirror->report_interval != 0)
607 		report_interval = (s64)mirror->report_interval * 1000LL;
608 	else if (layoutstats_timer != 0)
609 		report_interval = (s64)layoutstats_timer * 1000LL;
610 	if (ktime_to_ms(ktime_sub(now, ffl->last_report_time)) >=
611 			report_interval) {
612 		ffl->last_report_time = now;
613 		return true;
614 	}
615 
616 	return false;
617 }
618 
619 static void
620 nfs4_ff_layout_stat_io_update_requested(struct nfs4_ff_layoutstat *layoutstat,
621 		__u64 requested)
622 {
623 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
624 
625 	iostat->ops_requested++;
626 	iostat->bytes_requested += requested;
627 }
628 
629 static void
630 nfs4_ff_layout_stat_io_update_completed(struct nfs4_ff_layoutstat *layoutstat,
631 		__u64 requested,
632 		__u64 completed,
633 		ktime_t time_completed,
634 		ktime_t time_started)
635 {
636 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
637 	ktime_t completion_time = ktime_sub(time_completed, time_started);
638 	ktime_t timer;
639 
640 	iostat->ops_completed++;
641 	iostat->bytes_completed += completed;
642 	iostat->bytes_not_delivered += requested - completed;
643 
644 	timer = nfs4_ff_end_busy_timer(&layoutstat->busy_timer, time_completed);
645 	iostat->total_busy_time =
646 			ktime_add(iostat->total_busy_time, timer);
647 	iostat->aggregate_completion_time =
648 			ktime_add(iostat->aggregate_completion_time,
649 					completion_time);
650 }
651 
652 static void
653 nfs4_ff_layout_stat_io_start_read(struct inode *inode,
654 		struct nfs4_ff_layout_mirror *mirror,
655 		__u64 requested, ktime_t now)
656 {
657 	bool report;
658 
659 	spin_lock(&mirror->lock);
660 	report = nfs4_ff_layoutstat_start_io(mirror, &mirror->read_stat, now);
661 	nfs4_ff_layout_stat_io_update_requested(&mirror->read_stat, requested);
662 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
663 	spin_unlock(&mirror->lock);
664 
665 	if (report)
666 		pnfs_report_layoutstat(inode, GFP_KERNEL);
667 }
668 
669 static void
670 nfs4_ff_layout_stat_io_end_read(struct rpc_task *task,
671 		struct nfs4_ff_layout_mirror *mirror,
672 		__u64 requested,
673 		__u64 completed)
674 {
675 	spin_lock(&mirror->lock);
676 	nfs4_ff_layout_stat_io_update_completed(&mirror->read_stat,
677 			requested, completed,
678 			ktime_get(), task->tk_start);
679 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
680 	spin_unlock(&mirror->lock);
681 }
682 
683 static void
684 nfs4_ff_layout_stat_io_start_write(struct inode *inode,
685 		struct nfs4_ff_layout_mirror *mirror,
686 		__u64 requested, ktime_t now)
687 {
688 	bool report;
689 
690 	spin_lock(&mirror->lock);
691 	report = nfs4_ff_layoutstat_start_io(mirror , &mirror->write_stat, now);
692 	nfs4_ff_layout_stat_io_update_requested(&mirror->write_stat, requested);
693 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
694 	spin_unlock(&mirror->lock);
695 
696 	if (report)
697 		pnfs_report_layoutstat(inode, GFP_NOIO);
698 }
699 
700 static void
701 nfs4_ff_layout_stat_io_end_write(struct rpc_task *task,
702 		struct nfs4_ff_layout_mirror *mirror,
703 		__u64 requested,
704 		__u64 completed,
705 		enum nfs3_stable_how committed)
706 {
707 	if (committed == NFS_UNSTABLE)
708 		requested = completed = 0;
709 
710 	spin_lock(&mirror->lock);
711 	nfs4_ff_layout_stat_io_update_completed(&mirror->write_stat,
712 			requested, completed, ktime_get(), task->tk_start);
713 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
714 	spin_unlock(&mirror->lock);
715 }
716 
717 static void
718 ff_layout_mark_ds_unreachable(struct pnfs_layout_segment *lseg, u32 idx)
719 {
720 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
721 
722 	if (devid)
723 		nfs4_mark_deviceid_unavailable(devid);
724 }
725 
726 static void
727 ff_layout_mark_ds_reachable(struct pnfs_layout_segment *lseg, u32 idx)
728 {
729 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
730 
731 	if (devid)
732 		nfs4_mark_deviceid_available(devid);
733 }
734 
735 static struct nfs4_pnfs_ds *
736 ff_layout_choose_ds_for_read(struct pnfs_layout_segment *lseg,
737 			     u32 start_idx, u32 *best_idx,
738 			     bool check_device)
739 {
740 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
741 	struct nfs4_ff_layout_mirror *mirror;
742 	struct nfs4_pnfs_ds *ds;
743 	bool fail_return = false;
744 	u32 idx;
745 
746 	/* mirrors are initially sorted by efficiency */
747 	for (idx = start_idx; idx < fls->mirror_array_cnt; idx++) {
748 		if (idx+1 == fls->mirror_array_cnt)
749 			fail_return = !check_device;
750 
751 		mirror = FF_LAYOUT_COMP(lseg, idx);
752 		ds = nfs4_ff_layout_prepare_ds(lseg, mirror, fail_return);
753 		if (!ds)
754 			continue;
755 
756 		if (check_device &&
757 		    nfs4_test_deviceid_unavailable(&mirror->mirror_ds->id_node))
758 			continue;
759 
760 		*best_idx = idx;
761 		return ds;
762 	}
763 
764 	return NULL;
765 }
766 
767 static struct nfs4_pnfs_ds *
768 ff_layout_choose_any_ds_for_read(struct pnfs_layout_segment *lseg,
769 				 u32 start_idx, u32 *best_idx)
770 {
771 	return ff_layout_choose_ds_for_read(lseg, start_idx, best_idx, false);
772 }
773 
774 static struct nfs4_pnfs_ds *
775 ff_layout_choose_valid_ds_for_read(struct pnfs_layout_segment *lseg,
776 				   u32 start_idx, u32 *best_idx)
777 {
778 	return ff_layout_choose_ds_for_read(lseg, start_idx, best_idx, true);
779 }
780 
781 static struct nfs4_pnfs_ds *
782 ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg,
783 				  u32 start_idx, u32 *best_idx)
784 {
785 	struct nfs4_pnfs_ds *ds;
786 
787 	ds = ff_layout_choose_valid_ds_for_read(lseg, start_idx, best_idx);
788 	if (ds)
789 		return ds;
790 	return ff_layout_choose_any_ds_for_read(lseg, start_idx, best_idx);
791 }
792 
793 static struct nfs4_pnfs_ds *
794 ff_layout_get_ds_for_read(struct nfs_pageio_descriptor *pgio,
795 			  u32 *best_idx)
796 {
797 	struct pnfs_layout_segment *lseg = pgio->pg_lseg;
798 	struct nfs4_pnfs_ds *ds;
799 
800 	ds = ff_layout_choose_best_ds_for_read(lseg, pgio->pg_mirror_idx,
801 					       best_idx);
802 	if (ds || !pgio->pg_mirror_idx)
803 		return ds;
804 	return ff_layout_choose_best_ds_for_read(lseg, 0, best_idx);
805 }
806 
807 static void
808 ff_layout_pg_get_read(struct nfs_pageio_descriptor *pgio,
809 		      struct nfs_page *req,
810 		      bool strict_iomode)
811 {
812 	pnfs_put_lseg(pgio->pg_lseg);
813 	pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
814 					   nfs_req_openctx(req),
815 					   req_offset(req),
816 					   req->wb_bytes,
817 					   IOMODE_READ,
818 					   strict_iomode,
819 					   GFP_KERNEL);
820 	if (IS_ERR(pgio->pg_lseg)) {
821 		pgio->pg_error = PTR_ERR(pgio->pg_lseg);
822 		pgio->pg_lseg = NULL;
823 	}
824 }
825 
826 static void
827 ff_layout_pg_check_layout(struct nfs_pageio_descriptor *pgio,
828 			  struct nfs_page *req)
829 {
830 	pnfs_generic_pg_check_layout(pgio);
831 	pnfs_generic_pg_check_range(pgio, req);
832 }
833 
834 static void
835 ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
836 			struct nfs_page *req)
837 {
838 	struct nfs_pgio_mirror *pgm;
839 	struct nfs4_ff_layout_mirror *mirror;
840 	struct nfs4_pnfs_ds *ds;
841 	u32 ds_idx, i;
842 
843 retry:
844 	ff_layout_pg_check_layout(pgio, req);
845 	/* Use full layout for now */
846 	if (!pgio->pg_lseg) {
847 		ff_layout_pg_get_read(pgio, req, false);
848 		if (!pgio->pg_lseg)
849 			goto out_nolseg;
850 	}
851 	if (ff_layout_avoid_read_on_rw(pgio->pg_lseg)) {
852 		ff_layout_pg_get_read(pgio, req, true);
853 		if (!pgio->pg_lseg)
854 			goto out_nolseg;
855 	}
856 
857 	ds = ff_layout_get_ds_for_read(pgio, &ds_idx);
858 	if (!ds) {
859 		if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
860 			goto out_mds;
861 		pnfs_generic_pg_cleanup(pgio);
862 		/* Sleep for 1 second before retrying */
863 		ssleep(1);
864 		goto retry;
865 	}
866 
867 	for (i = 0; i < pgio->pg_mirror_count; i++) {
868 		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
869 		pgm = &pgio->pg_mirrors[i];
870 		pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].rsize;
871 	}
872 
873 	pgio->pg_mirror_idx = ds_idx;
874 
875 	if (NFS_SERVER(pgio->pg_inode)->flags &
876 			(NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR))
877 		pgio->pg_maxretrans = io_maxretrans;
878 	return;
879 out_nolseg:
880 	if (pgio->pg_error < 0)
881 		return;
882 out_mds:
883 	trace_pnfs_mds_fallback_pg_init_read(pgio->pg_inode,
884 			0, NFS4_MAX_UINT64, IOMODE_READ,
885 			NFS_I(pgio->pg_inode)->layout,
886 			pgio->pg_lseg);
887 	pgio->pg_maxretrans = 0;
888 	nfs_pageio_reset_read_mds(pgio);
889 }
890 
891 static void
892 ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
893 			struct nfs_page *req)
894 {
895 	struct nfs4_ff_layout_mirror *mirror;
896 	struct nfs_pgio_mirror *pgm;
897 	struct nfs4_pnfs_ds *ds;
898 	u32 i;
899 
900 retry:
901 	ff_layout_pg_check_layout(pgio, req);
902 	if (!pgio->pg_lseg) {
903 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
904 						   nfs_req_openctx(req),
905 						   req_offset(req),
906 						   req->wb_bytes,
907 						   IOMODE_RW,
908 						   false,
909 						   GFP_NOFS);
910 		if (IS_ERR(pgio->pg_lseg)) {
911 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
912 			pgio->pg_lseg = NULL;
913 			return;
914 		}
915 	}
916 	/* If no lseg, fall back to write through mds */
917 	if (pgio->pg_lseg == NULL)
918 		goto out_mds;
919 
920 	/* Use a direct mapping of ds_idx to pgio mirror_idx */
921 	if (pgio->pg_mirror_count != FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg))
922 		goto out_eagain;
923 
924 	for (i = 0; i < pgio->pg_mirror_count; i++) {
925 		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
926 		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, mirror, true);
927 		if (!ds) {
928 			if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
929 				goto out_mds;
930 			pnfs_generic_pg_cleanup(pgio);
931 			/* Sleep for 1 second before retrying */
932 			ssleep(1);
933 			goto retry;
934 		}
935 		pgm = &pgio->pg_mirrors[i];
936 		pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].wsize;
937 	}
938 
939 	if (NFS_SERVER(pgio->pg_inode)->flags &
940 			(NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR))
941 		pgio->pg_maxretrans = io_maxretrans;
942 	return;
943 out_eagain:
944 	pnfs_generic_pg_cleanup(pgio);
945 	pgio->pg_error = -EAGAIN;
946 	return;
947 out_mds:
948 	trace_pnfs_mds_fallback_pg_init_write(pgio->pg_inode,
949 			0, NFS4_MAX_UINT64, IOMODE_RW,
950 			NFS_I(pgio->pg_inode)->layout,
951 			pgio->pg_lseg);
952 	pgio->pg_maxretrans = 0;
953 	nfs_pageio_reset_write_mds(pgio);
954 	pgio->pg_error = -EAGAIN;
955 }
956 
957 static unsigned int
958 ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
959 				    struct nfs_page *req)
960 {
961 	if (!pgio->pg_lseg) {
962 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
963 						   nfs_req_openctx(req),
964 						   req_offset(req),
965 						   req->wb_bytes,
966 						   IOMODE_RW,
967 						   false,
968 						   GFP_NOFS);
969 		if (IS_ERR(pgio->pg_lseg)) {
970 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
971 			pgio->pg_lseg = NULL;
972 			goto out;
973 		}
974 	}
975 	if (pgio->pg_lseg)
976 		return FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg);
977 
978 	trace_pnfs_mds_fallback_pg_get_mirror_count(pgio->pg_inode,
979 			0, NFS4_MAX_UINT64, IOMODE_RW,
980 			NFS_I(pgio->pg_inode)->layout,
981 			pgio->pg_lseg);
982 	/* no lseg means that pnfs is not in use, so no mirroring here */
983 	nfs_pageio_reset_write_mds(pgio);
984 out:
985 	return 1;
986 }
987 
988 static const struct nfs_pageio_ops ff_layout_pg_read_ops = {
989 	.pg_init = ff_layout_pg_init_read,
990 	.pg_test = pnfs_generic_pg_test,
991 	.pg_doio = pnfs_generic_pg_readpages,
992 	.pg_cleanup = pnfs_generic_pg_cleanup,
993 };
994 
995 static const struct nfs_pageio_ops ff_layout_pg_write_ops = {
996 	.pg_init = ff_layout_pg_init_write,
997 	.pg_test = pnfs_generic_pg_test,
998 	.pg_doio = pnfs_generic_pg_writepages,
999 	.pg_get_mirror_count = ff_layout_pg_get_mirror_count_write,
1000 	.pg_cleanup = pnfs_generic_pg_cleanup,
1001 };
1002 
1003 static void ff_layout_reset_write(struct nfs_pgio_header *hdr, bool retry_pnfs)
1004 {
1005 	struct rpc_task *task = &hdr->task;
1006 
1007 	pnfs_layoutcommit_inode(hdr->inode, false);
1008 
1009 	if (retry_pnfs) {
1010 		dprintk("%s Reset task %5u for i/o through pNFS "
1011 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1012 			hdr->task.tk_pid,
1013 			hdr->inode->i_sb->s_id,
1014 			(unsigned long long)NFS_FILEID(hdr->inode),
1015 			hdr->args.count,
1016 			(unsigned long long)hdr->args.offset);
1017 
1018 		hdr->completion_ops->reschedule_io(hdr);
1019 		return;
1020 	}
1021 
1022 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1023 		dprintk("%s Reset task %5u for i/o through MDS "
1024 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1025 			hdr->task.tk_pid,
1026 			hdr->inode->i_sb->s_id,
1027 			(unsigned long long)NFS_FILEID(hdr->inode),
1028 			hdr->args.count,
1029 			(unsigned long long)hdr->args.offset);
1030 
1031 		trace_pnfs_mds_fallback_write_done(hdr->inode,
1032 				hdr->args.offset, hdr->args.count,
1033 				IOMODE_RW, NFS_I(hdr->inode)->layout,
1034 				hdr->lseg);
1035 		task->tk_status = pnfs_write_done_resend_to_mds(hdr);
1036 	}
1037 }
1038 
1039 static void ff_layout_resend_pnfs_read(struct nfs_pgio_header *hdr)
1040 {
1041 	u32 idx = hdr->pgio_mirror_idx + 1;
1042 	u32 new_idx = 0;
1043 
1044 	if (ff_layout_choose_any_ds_for_read(hdr->lseg, idx + 1, &new_idx))
1045 		ff_layout_send_layouterror(hdr->lseg);
1046 	else
1047 		pnfs_error_mark_layout_for_return(hdr->inode, hdr->lseg);
1048 	pnfs_read_resend_pnfs(hdr, new_idx);
1049 }
1050 
1051 static void ff_layout_reset_read(struct nfs_pgio_header *hdr)
1052 {
1053 	struct rpc_task *task = &hdr->task;
1054 
1055 	pnfs_layoutcommit_inode(hdr->inode, false);
1056 	pnfs_error_mark_layout_for_return(hdr->inode, hdr->lseg);
1057 
1058 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1059 		dprintk("%s Reset task %5u for i/o through MDS "
1060 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1061 			hdr->task.tk_pid,
1062 			hdr->inode->i_sb->s_id,
1063 			(unsigned long long)NFS_FILEID(hdr->inode),
1064 			hdr->args.count,
1065 			(unsigned long long)hdr->args.offset);
1066 
1067 		trace_pnfs_mds_fallback_read_done(hdr->inode,
1068 				hdr->args.offset, hdr->args.count,
1069 				IOMODE_READ, NFS_I(hdr->inode)->layout,
1070 				hdr->lseg);
1071 		task->tk_status = pnfs_read_done_resend_to_mds(hdr);
1072 	}
1073 }
1074 
1075 static int ff_layout_async_handle_error_v4(struct rpc_task *task,
1076 					   struct nfs4_state *state,
1077 					   struct nfs_client *clp,
1078 					   struct pnfs_layout_segment *lseg,
1079 					   u32 idx)
1080 {
1081 	struct pnfs_layout_hdr *lo = lseg->pls_layout;
1082 	struct inode *inode = lo->plh_inode;
1083 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1084 	struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
1085 
1086 	switch (task->tk_status) {
1087 	case -NFS4ERR_BADSESSION:
1088 	case -NFS4ERR_BADSLOT:
1089 	case -NFS4ERR_BAD_HIGH_SLOT:
1090 	case -NFS4ERR_DEADSESSION:
1091 	case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
1092 	case -NFS4ERR_SEQ_FALSE_RETRY:
1093 	case -NFS4ERR_SEQ_MISORDERED:
1094 		dprintk("%s ERROR %d, Reset session. Exchangeid "
1095 			"flags 0x%x\n", __func__, task->tk_status,
1096 			clp->cl_exchange_flags);
1097 		nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
1098 		break;
1099 	case -NFS4ERR_DELAY:
1100 	case -NFS4ERR_GRACE:
1101 		rpc_delay(task, FF_LAYOUT_POLL_RETRY_MAX);
1102 		break;
1103 	case -NFS4ERR_RETRY_UNCACHED_REP:
1104 		break;
1105 	/* Invalidate Layout errors */
1106 	case -NFS4ERR_PNFS_NO_LAYOUT:
1107 	case -ESTALE:           /* mapped NFS4ERR_STALE */
1108 	case -EBADHANDLE:       /* mapped NFS4ERR_BADHANDLE */
1109 	case -EISDIR:           /* mapped NFS4ERR_ISDIR */
1110 	case -NFS4ERR_FHEXPIRED:
1111 	case -NFS4ERR_WRONG_TYPE:
1112 		dprintk("%s Invalid layout error %d\n", __func__,
1113 			task->tk_status);
1114 		/*
1115 		 * Destroy layout so new i/o will get a new layout.
1116 		 * Layout will not be destroyed until all current lseg
1117 		 * references are put. Mark layout as invalid to resend failed
1118 		 * i/o and all i/o waiting on the slot table to the MDS until
1119 		 * layout is destroyed and a new valid layout is obtained.
1120 		 */
1121 		pnfs_destroy_layout(NFS_I(inode));
1122 		rpc_wake_up(&tbl->slot_tbl_waitq);
1123 		goto reset;
1124 	/* RPC connection errors */
1125 	case -ECONNREFUSED:
1126 	case -EHOSTDOWN:
1127 	case -EHOSTUNREACH:
1128 	case -ENETUNREACH:
1129 	case -EIO:
1130 	case -ETIMEDOUT:
1131 	case -EPIPE:
1132 		dprintk("%s DS connection error %d\n", __func__,
1133 			task->tk_status);
1134 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1135 				&devid->deviceid);
1136 		rpc_wake_up(&tbl->slot_tbl_waitq);
1137 		fallthrough;
1138 	default:
1139 		if (ff_layout_avoid_mds_available_ds(lseg))
1140 			return -NFS4ERR_RESET_TO_PNFS;
1141 reset:
1142 		dprintk("%s Retry through MDS. Error %d\n", __func__,
1143 			task->tk_status);
1144 		return -NFS4ERR_RESET_TO_MDS;
1145 	}
1146 	task->tk_status = 0;
1147 	return -EAGAIN;
1148 }
1149 
1150 /* Retry all errors through either pNFS or MDS except for -EJUKEBOX */
1151 static int ff_layout_async_handle_error_v3(struct rpc_task *task,
1152 					   struct pnfs_layout_segment *lseg,
1153 					   u32 idx)
1154 {
1155 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1156 
1157 	switch (task->tk_status) {
1158 	/* File access problems. Don't mark the device as unavailable */
1159 	case -EACCES:
1160 	case -ESTALE:
1161 	case -EISDIR:
1162 	case -EBADHANDLE:
1163 	case -ELOOP:
1164 	case -ENOSPC:
1165 		break;
1166 	case -EJUKEBOX:
1167 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1168 		goto out_retry;
1169 	default:
1170 		dprintk("%s DS connection error %d\n", __func__,
1171 			task->tk_status);
1172 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1173 				&devid->deviceid);
1174 	}
1175 	/* FIXME: Need to prevent infinite looping here. */
1176 	return -NFS4ERR_RESET_TO_PNFS;
1177 out_retry:
1178 	task->tk_status = 0;
1179 	rpc_restart_call_prepare(task);
1180 	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
1181 	return -EAGAIN;
1182 }
1183 
1184 static int ff_layout_async_handle_error(struct rpc_task *task,
1185 					struct nfs4_state *state,
1186 					struct nfs_client *clp,
1187 					struct pnfs_layout_segment *lseg,
1188 					u32 idx)
1189 {
1190 	int vers = clp->cl_nfs_mod->rpc_vers->number;
1191 
1192 	if (task->tk_status >= 0) {
1193 		ff_layout_mark_ds_reachable(lseg, idx);
1194 		return 0;
1195 	}
1196 
1197 	/* Handle the case of an invalid layout segment */
1198 	if (!pnfs_is_valid_lseg(lseg))
1199 		return -NFS4ERR_RESET_TO_PNFS;
1200 
1201 	switch (vers) {
1202 	case 3:
1203 		return ff_layout_async_handle_error_v3(task, lseg, idx);
1204 	case 4:
1205 		return ff_layout_async_handle_error_v4(task, state, clp,
1206 						       lseg, idx);
1207 	default:
1208 		/* should never happen */
1209 		WARN_ON_ONCE(1);
1210 		return 0;
1211 	}
1212 }
1213 
1214 static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg,
1215 					u32 idx, u64 offset, u64 length,
1216 					u32 *op_status, int opnum, int error)
1217 {
1218 	struct nfs4_ff_layout_mirror *mirror;
1219 	u32 status = *op_status;
1220 	int err;
1221 
1222 	if (status == 0) {
1223 		switch (error) {
1224 		case -ETIMEDOUT:
1225 		case -EPFNOSUPPORT:
1226 		case -EPROTONOSUPPORT:
1227 		case -EOPNOTSUPP:
1228 		case -ECONNREFUSED:
1229 		case -ECONNRESET:
1230 		case -EHOSTDOWN:
1231 		case -EHOSTUNREACH:
1232 		case -ENETUNREACH:
1233 		case -EADDRINUSE:
1234 		case -ENOBUFS:
1235 		case -EPIPE:
1236 		case -EPERM:
1237 			*op_status = status = NFS4ERR_NXIO;
1238 			break;
1239 		case -EACCES:
1240 			*op_status = status = NFS4ERR_ACCESS;
1241 			break;
1242 		default:
1243 			return;
1244 		}
1245 	}
1246 
1247 	mirror = FF_LAYOUT_COMP(lseg, idx);
1248 	err = ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),
1249 				       mirror, offset, length, status, opnum,
1250 				       GFP_NOIO);
1251 
1252 	switch (status) {
1253 	case NFS4ERR_DELAY:
1254 	case NFS4ERR_GRACE:
1255 		break;
1256 	case NFS4ERR_NXIO:
1257 		ff_layout_mark_ds_unreachable(lseg, idx);
1258 		/*
1259 		 * Don't return the layout if this is a read and we still
1260 		 * have layouts to try
1261 		 */
1262 		if (opnum == OP_READ)
1263 			break;
1264 		fallthrough;
1265 	default:
1266 		pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode,
1267 						  lseg);
1268 	}
1269 
1270 	dprintk("%s: err %d op %d status %u\n", __func__, err, opnum, status);
1271 }
1272 
1273 /* NFS_PROTO call done callback routines */
1274 static int ff_layout_read_done_cb(struct rpc_task *task,
1275 				struct nfs_pgio_header *hdr)
1276 {
1277 	int err;
1278 
1279 	if (task->tk_status < 0) {
1280 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1281 					    hdr->args.offset, hdr->args.count,
1282 					    &hdr->res.op_status, OP_READ,
1283 					    task->tk_status);
1284 		trace_ff_layout_read_error(hdr);
1285 	}
1286 
1287 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1288 					   hdr->ds_clp, hdr->lseg,
1289 					   hdr->pgio_mirror_idx);
1290 
1291 	trace_nfs4_pnfs_read(hdr, err);
1292 	clear_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1293 	clear_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1294 	switch (err) {
1295 	case -NFS4ERR_RESET_TO_PNFS:
1296 		set_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1297 		return task->tk_status;
1298 	case -NFS4ERR_RESET_TO_MDS:
1299 		set_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1300 		return task->tk_status;
1301 	case -EAGAIN:
1302 		goto out_eagain;
1303 	}
1304 
1305 	return 0;
1306 out_eagain:
1307 	rpc_restart_call_prepare(task);
1308 	return -EAGAIN;
1309 }
1310 
1311 static bool
1312 ff_layout_need_layoutcommit(struct pnfs_layout_segment *lseg)
1313 {
1314 	return !(FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_LAYOUTCOMMIT);
1315 }
1316 
1317 /*
1318  * We reference the rpc_cred of the first WRITE that triggers the need for
1319  * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
1320  * rfc5661 is not clear about which credential should be used.
1321  *
1322  * Flexlayout client should treat DS replied FILE_SYNC as DATA_SYNC, so
1323  * to follow http://www.rfc-editor.org/errata_search.php?rfc=5661&eid=2751
1324  * we always send layoutcommit after DS writes.
1325  */
1326 static void
1327 ff_layout_set_layoutcommit(struct inode *inode,
1328 		struct pnfs_layout_segment *lseg,
1329 		loff_t end_offset)
1330 {
1331 	if (!ff_layout_need_layoutcommit(lseg))
1332 		return;
1333 
1334 	pnfs_set_layoutcommit(inode, lseg, end_offset);
1335 	dprintk("%s inode %lu pls_end_pos %llu\n", __func__, inode->i_ino,
1336 		(unsigned long long) NFS_I(inode)->layout->plh_lwb);
1337 }
1338 
1339 static void ff_layout_read_record_layoutstats_start(struct rpc_task *task,
1340 		struct nfs_pgio_header *hdr)
1341 {
1342 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1343 		return;
1344 	nfs4_ff_layout_stat_io_start_read(hdr->inode,
1345 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1346 			hdr->args.count,
1347 			task->tk_start);
1348 }
1349 
1350 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
1351 		struct nfs_pgio_header *hdr)
1352 {
1353 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1354 		return;
1355 	nfs4_ff_layout_stat_io_end_read(task,
1356 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1357 			hdr->args.count,
1358 			hdr->res.count);
1359 	set_bit(NFS_LSEG_LAYOUTRETURN, &hdr->lseg->pls_flags);
1360 }
1361 
1362 static int ff_layout_read_prepare_common(struct rpc_task *task,
1363 					 struct nfs_pgio_header *hdr)
1364 {
1365 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1366 		rpc_exit(task, -EIO);
1367 		return -EIO;
1368 	}
1369 
1370 	ff_layout_read_record_layoutstats_start(task, hdr);
1371 	return 0;
1372 }
1373 
1374 /*
1375  * Call ops for the async read/write cases
1376  * In the case of dense layouts, the offset needs to be reset to its
1377  * original value.
1378  */
1379 static void ff_layout_read_prepare_v3(struct rpc_task *task, void *data)
1380 {
1381 	struct nfs_pgio_header *hdr = data;
1382 
1383 	if (ff_layout_read_prepare_common(task, hdr))
1384 		return;
1385 
1386 	rpc_call_start(task);
1387 }
1388 
1389 static void ff_layout_read_prepare_v4(struct rpc_task *task, void *data)
1390 {
1391 	struct nfs_pgio_header *hdr = data;
1392 
1393 	if (nfs4_setup_sequence(hdr->ds_clp,
1394 				&hdr->args.seq_args,
1395 				&hdr->res.seq_res,
1396 				task))
1397 		return;
1398 
1399 	ff_layout_read_prepare_common(task, hdr);
1400 }
1401 
1402 static void ff_layout_read_call_done(struct rpc_task *task, void *data)
1403 {
1404 	struct nfs_pgio_header *hdr = data;
1405 
1406 	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
1407 
1408 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1409 	    task->tk_status == 0) {
1410 		nfs4_sequence_done(task, &hdr->res.seq_res);
1411 		return;
1412 	}
1413 
1414 	/* Note this may cause RPC to be resent */
1415 	hdr->mds_ops->rpc_call_done(task, hdr);
1416 }
1417 
1418 static void ff_layout_read_count_stats(struct rpc_task *task, void *data)
1419 {
1420 	struct nfs_pgio_header *hdr = data;
1421 
1422 	ff_layout_read_record_layoutstats_done(task, hdr);
1423 	rpc_count_iostats_metrics(task,
1424 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_READ]);
1425 }
1426 
1427 static void ff_layout_read_release(void *data)
1428 {
1429 	struct nfs_pgio_header *hdr = data;
1430 
1431 	ff_layout_read_record_layoutstats_done(&hdr->task, hdr);
1432 	if (test_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags))
1433 		ff_layout_resend_pnfs_read(hdr);
1434 	else if (test_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags))
1435 		ff_layout_reset_read(hdr);
1436 	pnfs_generic_rw_release(data);
1437 }
1438 
1439 
1440 static int ff_layout_write_done_cb(struct rpc_task *task,
1441 				struct nfs_pgio_header *hdr)
1442 {
1443 	loff_t end_offs = 0;
1444 	int err;
1445 
1446 	if (task->tk_status < 0) {
1447 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1448 					    hdr->args.offset, hdr->args.count,
1449 					    &hdr->res.op_status, OP_WRITE,
1450 					    task->tk_status);
1451 		trace_ff_layout_write_error(hdr);
1452 	}
1453 
1454 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1455 					   hdr->ds_clp, hdr->lseg,
1456 					   hdr->pgio_mirror_idx);
1457 
1458 	trace_nfs4_pnfs_write(hdr, err);
1459 	clear_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1460 	clear_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1461 	switch (err) {
1462 	case -NFS4ERR_RESET_TO_PNFS:
1463 		set_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1464 		return task->tk_status;
1465 	case -NFS4ERR_RESET_TO_MDS:
1466 		set_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1467 		return task->tk_status;
1468 	case -EAGAIN:
1469 		return -EAGAIN;
1470 	}
1471 
1472 	if (hdr->res.verf->committed == NFS_FILE_SYNC ||
1473 	    hdr->res.verf->committed == NFS_DATA_SYNC)
1474 		end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
1475 
1476 	/* Note: if the write is unstable, don't set end_offs until commit */
1477 	ff_layout_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
1478 
1479 	/* zero out fattr since we don't care DS attr at all */
1480 	hdr->fattr.valid = 0;
1481 	if (task->tk_status >= 0)
1482 		nfs_writeback_update_inode(hdr);
1483 
1484 	return 0;
1485 }
1486 
1487 static int ff_layout_commit_done_cb(struct rpc_task *task,
1488 				     struct nfs_commit_data *data)
1489 {
1490 	int err;
1491 
1492 	if (task->tk_status < 0) {
1493 		ff_layout_io_track_ds_error(data->lseg, data->ds_commit_index,
1494 					    data->args.offset, data->args.count,
1495 					    &data->res.op_status, OP_COMMIT,
1496 					    task->tk_status);
1497 		trace_ff_layout_commit_error(data);
1498 	}
1499 
1500 	err = ff_layout_async_handle_error(task, NULL, data->ds_clp,
1501 					   data->lseg, data->ds_commit_index);
1502 
1503 	trace_nfs4_pnfs_commit_ds(data, err);
1504 	switch (err) {
1505 	case -NFS4ERR_RESET_TO_PNFS:
1506 		pnfs_generic_prepare_to_resend_writes(data);
1507 		return -EAGAIN;
1508 	case -NFS4ERR_RESET_TO_MDS:
1509 		pnfs_generic_prepare_to_resend_writes(data);
1510 		return -EAGAIN;
1511 	case -EAGAIN:
1512 		rpc_restart_call_prepare(task);
1513 		return -EAGAIN;
1514 	}
1515 
1516 	ff_layout_set_layoutcommit(data->inode, data->lseg, data->lwb);
1517 
1518 	return 0;
1519 }
1520 
1521 static void ff_layout_write_record_layoutstats_start(struct rpc_task *task,
1522 		struct nfs_pgio_header *hdr)
1523 {
1524 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1525 		return;
1526 	nfs4_ff_layout_stat_io_start_write(hdr->inode,
1527 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1528 			hdr->args.count,
1529 			task->tk_start);
1530 }
1531 
1532 static void ff_layout_write_record_layoutstats_done(struct rpc_task *task,
1533 		struct nfs_pgio_header *hdr)
1534 {
1535 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1536 		return;
1537 	nfs4_ff_layout_stat_io_end_write(task,
1538 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1539 			hdr->args.count, hdr->res.count,
1540 			hdr->res.verf->committed);
1541 	set_bit(NFS_LSEG_LAYOUTRETURN, &hdr->lseg->pls_flags);
1542 }
1543 
1544 static int ff_layout_write_prepare_common(struct rpc_task *task,
1545 					  struct nfs_pgio_header *hdr)
1546 {
1547 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1548 		rpc_exit(task, -EIO);
1549 		return -EIO;
1550 	}
1551 
1552 	ff_layout_write_record_layoutstats_start(task, hdr);
1553 	return 0;
1554 }
1555 
1556 static void ff_layout_write_prepare_v3(struct rpc_task *task, void *data)
1557 {
1558 	struct nfs_pgio_header *hdr = data;
1559 
1560 	if (ff_layout_write_prepare_common(task, hdr))
1561 		return;
1562 
1563 	rpc_call_start(task);
1564 }
1565 
1566 static void ff_layout_write_prepare_v4(struct rpc_task *task, void *data)
1567 {
1568 	struct nfs_pgio_header *hdr = data;
1569 
1570 	if (nfs4_setup_sequence(hdr->ds_clp,
1571 				&hdr->args.seq_args,
1572 				&hdr->res.seq_res,
1573 				task))
1574 		return;
1575 
1576 	ff_layout_write_prepare_common(task, hdr);
1577 }
1578 
1579 static void ff_layout_write_call_done(struct rpc_task *task, void *data)
1580 {
1581 	struct nfs_pgio_header *hdr = data;
1582 
1583 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1584 	    task->tk_status == 0) {
1585 		nfs4_sequence_done(task, &hdr->res.seq_res);
1586 		return;
1587 	}
1588 
1589 	/* Note this may cause RPC to be resent */
1590 	hdr->mds_ops->rpc_call_done(task, hdr);
1591 }
1592 
1593 static void ff_layout_write_count_stats(struct rpc_task *task, void *data)
1594 {
1595 	struct nfs_pgio_header *hdr = data;
1596 
1597 	ff_layout_write_record_layoutstats_done(task, hdr);
1598 	rpc_count_iostats_metrics(task,
1599 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_WRITE]);
1600 }
1601 
1602 static void ff_layout_write_release(void *data)
1603 {
1604 	struct nfs_pgio_header *hdr = data;
1605 
1606 	ff_layout_write_record_layoutstats_done(&hdr->task, hdr);
1607 	if (test_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags)) {
1608 		ff_layout_send_layouterror(hdr->lseg);
1609 		ff_layout_reset_write(hdr, true);
1610 	} else if (test_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags))
1611 		ff_layout_reset_write(hdr, false);
1612 	pnfs_generic_rw_release(data);
1613 }
1614 
1615 static void ff_layout_commit_record_layoutstats_start(struct rpc_task *task,
1616 		struct nfs_commit_data *cdata)
1617 {
1618 	if (test_and_set_bit(NFS_IOHDR_STAT, &cdata->flags))
1619 		return;
1620 	nfs4_ff_layout_stat_io_start_write(cdata->inode,
1621 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1622 			0, task->tk_start);
1623 }
1624 
1625 static void ff_layout_commit_record_layoutstats_done(struct rpc_task *task,
1626 		struct nfs_commit_data *cdata)
1627 {
1628 	struct nfs_page *req;
1629 	__u64 count = 0;
1630 
1631 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &cdata->flags))
1632 		return;
1633 
1634 	if (task->tk_status == 0) {
1635 		list_for_each_entry(req, &cdata->pages, wb_list)
1636 			count += req->wb_bytes;
1637 	}
1638 	nfs4_ff_layout_stat_io_end_write(task,
1639 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1640 			count, count, NFS_FILE_SYNC);
1641 	set_bit(NFS_LSEG_LAYOUTRETURN, &cdata->lseg->pls_flags);
1642 }
1643 
1644 static void ff_layout_commit_prepare_common(struct rpc_task *task,
1645 		struct nfs_commit_data *cdata)
1646 {
1647 	ff_layout_commit_record_layoutstats_start(task, cdata);
1648 }
1649 
1650 static void ff_layout_commit_prepare_v3(struct rpc_task *task, void *data)
1651 {
1652 	ff_layout_commit_prepare_common(task, data);
1653 	rpc_call_start(task);
1654 }
1655 
1656 static void ff_layout_commit_prepare_v4(struct rpc_task *task, void *data)
1657 {
1658 	struct nfs_commit_data *wdata = data;
1659 
1660 	if (nfs4_setup_sequence(wdata->ds_clp,
1661 				&wdata->args.seq_args,
1662 				&wdata->res.seq_res,
1663 				task))
1664 		return;
1665 	ff_layout_commit_prepare_common(task, data);
1666 }
1667 
1668 static void ff_layout_commit_done(struct rpc_task *task, void *data)
1669 {
1670 	pnfs_generic_write_commit_done(task, data);
1671 }
1672 
1673 static void ff_layout_commit_count_stats(struct rpc_task *task, void *data)
1674 {
1675 	struct nfs_commit_data *cdata = data;
1676 
1677 	ff_layout_commit_record_layoutstats_done(task, cdata);
1678 	rpc_count_iostats_metrics(task,
1679 	    &NFS_CLIENT(cdata->inode)->cl_metrics[NFSPROC4_CLNT_COMMIT]);
1680 }
1681 
1682 static void ff_layout_commit_release(void *data)
1683 {
1684 	struct nfs_commit_data *cdata = data;
1685 
1686 	ff_layout_commit_record_layoutstats_done(&cdata->task, cdata);
1687 	pnfs_generic_commit_release(data);
1688 }
1689 
1690 static const struct rpc_call_ops ff_layout_read_call_ops_v3 = {
1691 	.rpc_call_prepare = ff_layout_read_prepare_v3,
1692 	.rpc_call_done = ff_layout_read_call_done,
1693 	.rpc_count_stats = ff_layout_read_count_stats,
1694 	.rpc_release = ff_layout_read_release,
1695 };
1696 
1697 static const struct rpc_call_ops ff_layout_read_call_ops_v4 = {
1698 	.rpc_call_prepare = ff_layout_read_prepare_v4,
1699 	.rpc_call_done = ff_layout_read_call_done,
1700 	.rpc_count_stats = ff_layout_read_count_stats,
1701 	.rpc_release = ff_layout_read_release,
1702 };
1703 
1704 static const struct rpc_call_ops ff_layout_write_call_ops_v3 = {
1705 	.rpc_call_prepare = ff_layout_write_prepare_v3,
1706 	.rpc_call_done = ff_layout_write_call_done,
1707 	.rpc_count_stats = ff_layout_write_count_stats,
1708 	.rpc_release = ff_layout_write_release,
1709 };
1710 
1711 static const struct rpc_call_ops ff_layout_write_call_ops_v4 = {
1712 	.rpc_call_prepare = ff_layout_write_prepare_v4,
1713 	.rpc_call_done = ff_layout_write_call_done,
1714 	.rpc_count_stats = ff_layout_write_count_stats,
1715 	.rpc_release = ff_layout_write_release,
1716 };
1717 
1718 static const struct rpc_call_ops ff_layout_commit_call_ops_v3 = {
1719 	.rpc_call_prepare = ff_layout_commit_prepare_v3,
1720 	.rpc_call_done = ff_layout_commit_done,
1721 	.rpc_count_stats = ff_layout_commit_count_stats,
1722 	.rpc_release = ff_layout_commit_release,
1723 };
1724 
1725 static const struct rpc_call_ops ff_layout_commit_call_ops_v4 = {
1726 	.rpc_call_prepare = ff_layout_commit_prepare_v4,
1727 	.rpc_call_done = ff_layout_commit_done,
1728 	.rpc_count_stats = ff_layout_commit_count_stats,
1729 	.rpc_release = ff_layout_commit_release,
1730 };
1731 
1732 static enum pnfs_try_status
1733 ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
1734 {
1735 	struct pnfs_layout_segment *lseg = hdr->lseg;
1736 	struct nfs4_pnfs_ds *ds;
1737 	struct rpc_clnt *ds_clnt;
1738 	struct nfs4_ff_layout_mirror *mirror;
1739 	const struct cred *ds_cred;
1740 	loff_t offset = hdr->args.offset;
1741 	u32 idx = hdr->pgio_mirror_idx;
1742 	int vers;
1743 	struct nfs_fh *fh;
1744 
1745 	dprintk("--> %s ino %lu pgbase %u req %zu@%llu\n",
1746 		__func__, hdr->inode->i_ino,
1747 		hdr->args.pgbase, (size_t)hdr->args.count, offset);
1748 
1749 	mirror = FF_LAYOUT_COMP(lseg, idx);
1750 	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, false);
1751 	if (!ds)
1752 		goto out_failed;
1753 
1754 	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,
1755 						   hdr->inode);
1756 	if (IS_ERR(ds_clnt))
1757 		goto out_failed;
1758 
1759 	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, hdr->cred);
1760 	if (!ds_cred)
1761 		goto out_failed;
1762 
1763 	vers = nfs4_ff_layout_ds_version(mirror);
1764 
1765 	dprintk("%s USE DS: %s cl_count %d vers %d\n", __func__,
1766 		ds->ds_remotestr, refcount_read(&ds->ds_clp->cl_count), vers);
1767 
1768 	hdr->pgio_done_cb = ff_layout_read_done_cb;
1769 	refcount_inc(&ds->ds_clp->cl_count);
1770 	hdr->ds_clp = ds->ds_clp;
1771 	fh = nfs4_ff_layout_select_ds_fh(mirror);
1772 	if (fh)
1773 		hdr->args.fh = fh;
1774 
1775 	nfs4_ff_layout_select_ds_stateid(mirror, &hdr->args.stateid);
1776 
1777 	/*
1778 	 * Note that if we ever decide to split across DSes,
1779 	 * then we may need to handle dense-like offsets.
1780 	 */
1781 	hdr->args.offset = offset;
1782 	hdr->mds_offset = offset;
1783 
1784 	/* Perform an asynchronous read to ds */
1785 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1786 			  vers == 3 ? &ff_layout_read_call_ops_v3 :
1787 				      &ff_layout_read_call_ops_v4,
1788 			  0, RPC_TASK_SOFTCONN);
1789 	put_cred(ds_cred);
1790 	return PNFS_ATTEMPTED;
1791 
1792 out_failed:
1793 	if (ff_layout_avoid_mds_available_ds(lseg))
1794 		return PNFS_TRY_AGAIN;
1795 	trace_pnfs_mds_fallback_read_pagelist(hdr->inode,
1796 			hdr->args.offset, hdr->args.count,
1797 			IOMODE_READ, NFS_I(hdr->inode)->layout, lseg);
1798 	return PNFS_NOT_ATTEMPTED;
1799 }
1800 
1801 /* Perform async writes. */
1802 static enum pnfs_try_status
1803 ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
1804 {
1805 	struct pnfs_layout_segment *lseg = hdr->lseg;
1806 	struct nfs4_pnfs_ds *ds;
1807 	struct rpc_clnt *ds_clnt;
1808 	struct nfs4_ff_layout_mirror *mirror;
1809 	const struct cred *ds_cred;
1810 	loff_t offset = hdr->args.offset;
1811 	int vers;
1812 	struct nfs_fh *fh;
1813 	u32 idx = hdr->pgio_mirror_idx;
1814 
1815 	mirror = FF_LAYOUT_COMP(lseg, idx);
1816 	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, true);
1817 	if (!ds)
1818 		goto out_failed;
1819 
1820 	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,
1821 						   hdr->inode);
1822 	if (IS_ERR(ds_clnt))
1823 		goto out_failed;
1824 
1825 	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, hdr->cred);
1826 	if (!ds_cred)
1827 		goto out_failed;
1828 
1829 	vers = nfs4_ff_layout_ds_version(mirror);
1830 
1831 	dprintk("%s ino %lu sync %d req %zu@%llu DS: %s cl_count %d vers %d\n",
1832 		__func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
1833 		offset, ds->ds_remotestr, refcount_read(&ds->ds_clp->cl_count),
1834 		vers);
1835 
1836 	hdr->pgio_done_cb = ff_layout_write_done_cb;
1837 	refcount_inc(&ds->ds_clp->cl_count);
1838 	hdr->ds_clp = ds->ds_clp;
1839 	hdr->ds_commit_idx = idx;
1840 	fh = nfs4_ff_layout_select_ds_fh(mirror);
1841 	if (fh)
1842 		hdr->args.fh = fh;
1843 
1844 	nfs4_ff_layout_select_ds_stateid(mirror, &hdr->args.stateid);
1845 
1846 	/*
1847 	 * Note that if we ever decide to split across DSes,
1848 	 * then we may need to handle dense-like offsets.
1849 	 */
1850 	hdr->args.offset = offset;
1851 
1852 	/* Perform an asynchronous write */
1853 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1854 			  vers == 3 ? &ff_layout_write_call_ops_v3 :
1855 				      &ff_layout_write_call_ops_v4,
1856 			  sync, RPC_TASK_SOFTCONN);
1857 	put_cred(ds_cred);
1858 	return PNFS_ATTEMPTED;
1859 
1860 out_failed:
1861 	if (ff_layout_avoid_mds_available_ds(lseg))
1862 		return PNFS_TRY_AGAIN;
1863 	trace_pnfs_mds_fallback_write_pagelist(hdr->inode,
1864 			hdr->args.offset, hdr->args.count,
1865 			IOMODE_RW, NFS_I(hdr->inode)->layout, lseg);
1866 	return PNFS_NOT_ATTEMPTED;
1867 }
1868 
1869 static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1870 {
1871 	return i;
1872 }
1873 
1874 static struct nfs_fh *
1875 select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1876 {
1877 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
1878 
1879 	/* FIXME: Assume that there is only one NFS version available
1880 	 * for the DS.
1881 	 */
1882 	return &flseg->mirror_array[i]->fh_versions[0];
1883 }
1884 
1885 static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
1886 {
1887 	struct pnfs_layout_segment *lseg = data->lseg;
1888 	struct nfs4_pnfs_ds *ds;
1889 	struct rpc_clnt *ds_clnt;
1890 	struct nfs4_ff_layout_mirror *mirror;
1891 	const struct cred *ds_cred;
1892 	u32 idx;
1893 	int vers, ret;
1894 	struct nfs_fh *fh;
1895 
1896 	if (!lseg || !(pnfs_is_valid_lseg(lseg) ||
1897 	    test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags)))
1898 		goto out_err;
1899 
1900 	idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
1901 	mirror = FF_LAYOUT_COMP(lseg, idx);
1902 	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, true);
1903 	if (!ds)
1904 		goto out_err;
1905 
1906 	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,
1907 						   data->inode);
1908 	if (IS_ERR(ds_clnt))
1909 		goto out_err;
1910 
1911 	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, data->cred);
1912 	if (!ds_cred)
1913 		goto out_err;
1914 
1915 	vers = nfs4_ff_layout_ds_version(mirror);
1916 
1917 	dprintk("%s ino %lu, how %d cl_count %d vers %d\n", __func__,
1918 		data->inode->i_ino, how, refcount_read(&ds->ds_clp->cl_count),
1919 		vers);
1920 	data->commit_done_cb = ff_layout_commit_done_cb;
1921 	data->cred = ds_cred;
1922 	refcount_inc(&ds->ds_clp->cl_count);
1923 	data->ds_clp = ds->ds_clp;
1924 	fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
1925 	if (fh)
1926 		data->args.fh = fh;
1927 
1928 	ret = nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
1929 				   vers == 3 ? &ff_layout_commit_call_ops_v3 :
1930 					       &ff_layout_commit_call_ops_v4,
1931 				   how, RPC_TASK_SOFTCONN);
1932 	put_cred(ds_cred);
1933 	return ret;
1934 out_err:
1935 	pnfs_generic_prepare_to_resend_writes(data);
1936 	pnfs_generic_commit_release(data);
1937 	return -EAGAIN;
1938 }
1939 
1940 static int
1941 ff_layout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
1942 			   int how, struct nfs_commit_info *cinfo)
1943 {
1944 	return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
1945 					    ff_layout_initiate_commit);
1946 }
1947 
1948 static struct pnfs_ds_commit_info *
1949 ff_layout_get_ds_info(struct inode *inode)
1950 {
1951 	struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
1952 
1953 	if (layout == NULL)
1954 		return NULL;
1955 
1956 	return &FF_LAYOUT_FROM_HDR(layout)->commit_info;
1957 }
1958 
1959 static void
1960 ff_layout_setup_ds_info(struct pnfs_ds_commit_info *fl_cinfo,
1961 		struct pnfs_layout_segment *lseg)
1962 {
1963 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
1964 	struct inode *inode = lseg->pls_layout->plh_inode;
1965 	struct pnfs_commit_array *array, *new;
1966 
1967 	new = pnfs_alloc_commit_array(flseg->mirror_array_cnt, GFP_NOIO);
1968 	if (new) {
1969 		spin_lock(&inode->i_lock);
1970 		array = pnfs_add_commit_array(fl_cinfo, new, lseg);
1971 		spin_unlock(&inode->i_lock);
1972 		if (array != new)
1973 			pnfs_free_commit_array(new);
1974 	}
1975 }
1976 
1977 static void
1978 ff_layout_release_ds_info(struct pnfs_ds_commit_info *fl_cinfo,
1979 		struct inode *inode)
1980 {
1981 	spin_lock(&inode->i_lock);
1982 	pnfs_generic_ds_cinfo_destroy(fl_cinfo);
1983 	spin_unlock(&inode->i_lock);
1984 }
1985 
1986 static void
1987 ff_layout_free_deviceid_node(struct nfs4_deviceid_node *d)
1988 {
1989 	nfs4_ff_layout_free_deviceid(container_of(d, struct nfs4_ff_layout_ds,
1990 						  id_node));
1991 }
1992 
1993 static int ff_layout_encode_ioerr(struct xdr_stream *xdr,
1994 				  const struct nfs4_layoutreturn_args *args,
1995 				  const struct nfs4_flexfile_layoutreturn_args *ff_args)
1996 {
1997 	__be32 *start;
1998 
1999 	start = xdr_reserve_space(xdr, 4);
2000 	if (unlikely(!start))
2001 		return -E2BIG;
2002 
2003 	*start = cpu_to_be32(ff_args->num_errors);
2004 	/* This assume we always return _ALL_ layouts */
2005 	return ff_layout_encode_ds_ioerr(xdr, &ff_args->errors);
2006 }
2007 
2008 static void
2009 encode_opaque_fixed(struct xdr_stream *xdr, const void *buf, size_t len)
2010 {
2011 	WARN_ON_ONCE(xdr_stream_encode_opaque_fixed(xdr, buf, len) < 0);
2012 }
2013 
2014 static void
2015 ff_layout_encode_ff_iostat_head(struct xdr_stream *xdr,
2016 			    const nfs4_stateid *stateid,
2017 			    const struct nfs42_layoutstat_devinfo *devinfo)
2018 {
2019 	__be32 *p;
2020 
2021 	p = xdr_reserve_space(xdr, 8 + 8);
2022 	p = xdr_encode_hyper(p, devinfo->offset);
2023 	p = xdr_encode_hyper(p, devinfo->length);
2024 	encode_opaque_fixed(xdr, stateid->data, NFS4_STATEID_SIZE);
2025 	p = xdr_reserve_space(xdr, 4*8);
2026 	p = xdr_encode_hyper(p, devinfo->read_count);
2027 	p = xdr_encode_hyper(p, devinfo->read_bytes);
2028 	p = xdr_encode_hyper(p, devinfo->write_count);
2029 	p = xdr_encode_hyper(p, devinfo->write_bytes);
2030 	encode_opaque_fixed(xdr, devinfo->dev_id.data, NFS4_DEVICEID4_SIZE);
2031 }
2032 
2033 static void
2034 ff_layout_encode_ff_iostat(struct xdr_stream *xdr,
2035 			    const nfs4_stateid *stateid,
2036 			    const struct nfs42_layoutstat_devinfo *devinfo)
2037 {
2038 	ff_layout_encode_ff_iostat_head(xdr, stateid, devinfo);
2039 	ff_layout_encode_ff_layoutupdate(xdr, devinfo,
2040 			devinfo->ld_private.data);
2041 }
2042 
2043 /* report nothing for now */
2044 static void ff_layout_encode_iostats_array(struct xdr_stream *xdr,
2045 		const struct nfs4_layoutreturn_args *args,
2046 		struct nfs4_flexfile_layoutreturn_args *ff_args)
2047 {
2048 	__be32 *p;
2049 	int i;
2050 
2051 	p = xdr_reserve_space(xdr, 4);
2052 	*p = cpu_to_be32(ff_args->num_dev);
2053 	for (i = 0; i < ff_args->num_dev; i++)
2054 		ff_layout_encode_ff_iostat(xdr,
2055 				&args->layout->plh_stateid,
2056 				&ff_args->devinfo[i]);
2057 }
2058 
2059 static void
2060 ff_layout_free_iostats_array(struct nfs42_layoutstat_devinfo *devinfo,
2061 		unsigned int num_entries)
2062 {
2063 	unsigned int i;
2064 
2065 	for (i = 0; i < num_entries; i++) {
2066 		if (!devinfo[i].ld_private.ops)
2067 			continue;
2068 		if (!devinfo[i].ld_private.ops->free)
2069 			continue;
2070 		devinfo[i].ld_private.ops->free(&devinfo[i].ld_private);
2071 	}
2072 }
2073 
2074 static struct nfs4_deviceid_node *
2075 ff_layout_alloc_deviceid_node(struct nfs_server *server,
2076 			      struct pnfs_device *pdev, gfp_t gfp_flags)
2077 {
2078 	struct nfs4_ff_layout_ds *dsaddr;
2079 
2080 	dsaddr = nfs4_ff_alloc_deviceid_node(server, pdev, gfp_flags);
2081 	if (!dsaddr)
2082 		return NULL;
2083 	return &dsaddr->id_node;
2084 }
2085 
2086 static void
2087 ff_layout_encode_layoutreturn(struct xdr_stream *xdr,
2088 		const void *voidargs,
2089 		const struct nfs4_xdr_opaque_data *ff_opaque)
2090 {
2091 	const struct nfs4_layoutreturn_args *args = voidargs;
2092 	struct nfs4_flexfile_layoutreturn_args *ff_args = ff_opaque->data;
2093 	struct xdr_buf tmp_buf = {
2094 		.head = {
2095 			[0] = {
2096 				.iov_base = page_address(ff_args->pages[0]),
2097 			},
2098 		},
2099 		.buflen = PAGE_SIZE,
2100 	};
2101 	struct xdr_stream tmp_xdr;
2102 	__be32 *start;
2103 
2104 	dprintk("%s: Begin\n", __func__);
2105 
2106 	xdr_init_encode(&tmp_xdr, &tmp_buf, NULL, NULL);
2107 
2108 	ff_layout_encode_ioerr(&tmp_xdr, args, ff_args);
2109 	ff_layout_encode_iostats_array(&tmp_xdr, args, ff_args);
2110 
2111 	start = xdr_reserve_space(xdr, 4);
2112 	*start = cpu_to_be32(tmp_buf.len);
2113 	xdr_write_pages(xdr, ff_args->pages, 0, tmp_buf.len);
2114 
2115 	dprintk("%s: Return\n", __func__);
2116 }
2117 
2118 static void
2119 ff_layout_free_layoutreturn(struct nfs4_xdr_opaque_data *args)
2120 {
2121 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2122 
2123 	if (!args->data)
2124 		return;
2125 	ff_args = args->data;
2126 	args->data = NULL;
2127 
2128 	ff_layout_free_ds_ioerr(&ff_args->errors);
2129 	ff_layout_free_iostats_array(ff_args->devinfo, ff_args->num_dev);
2130 
2131 	put_page(ff_args->pages[0]);
2132 	kfree(ff_args);
2133 }
2134 
2135 static const struct nfs4_xdr_opaque_ops layoutreturn_ops = {
2136 	.encode = ff_layout_encode_layoutreturn,
2137 	.free = ff_layout_free_layoutreturn,
2138 };
2139 
2140 static int
2141 ff_layout_prepare_layoutreturn(struct nfs4_layoutreturn_args *args)
2142 {
2143 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2144 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(args->layout);
2145 
2146 	ff_args = kmalloc(sizeof(*ff_args), GFP_KERNEL);
2147 	if (!ff_args)
2148 		goto out_nomem;
2149 	ff_args->pages[0] = alloc_page(GFP_KERNEL);
2150 	if (!ff_args->pages[0])
2151 		goto out_nomem_free;
2152 
2153 	INIT_LIST_HEAD(&ff_args->errors);
2154 	ff_args->num_errors = ff_layout_fetch_ds_ioerr(args->layout,
2155 			&args->range, &ff_args->errors,
2156 			FF_LAYOUTRETURN_MAXERR);
2157 
2158 	spin_lock(&args->inode->i_lock);
2159 	ff_args->num_dev = ff_layout_mirror_prepare_stats(&ff_layout->generic_hdr,
2160 			&ff_args->devinfo[0], ARRAY_SIZE(ff_args->devinfo));
2161 	spin_unlock(&args->inode->i_lock);
2162 
2163 	args->ld_private->ops = &layoutreturn_ops;
2164 	args->ld_private->data = ff_args;
2165 	return 0;
2166 out_nomem_free:
2167 	kfree(ff_args);
2168 out_nomem:
2169 	return -ENOMEM;
2170 }
2171 
2172 #ifdef CONFIG_NFS_V4_2
2173 void
2174 ff_layout_send_layouterror(struct pnfs_layout_segment *lseg)
2175 {
2176 	struct pnfs_layout_hdr *lo = lseg->pls_layout;
2177 	struct nfs42_layout_error *errors;
2178 	LIST_HEAD(head);
2179 
2180 	if (!nfs_server_capable(lo->plh_inode, NFS_CAP_LAYOUTERROR))
2181 		return;
2182 	ff_layout_fetch_ds_ioerr(lo, &lseg->pls_range, &head, -1);
2183 	if (list_empty(&head))
2184 		return;
2185 
2186 	errors = kmalloc_array(NFS42_LAYOUTERROR_MAX,
2187 			sizeof(*errors), GFP_NOFS);
2188 	if (errors != NULL) {
2189 		const struct nfs4_ff_layout_ds_err *pos;
2190 		size_t n = 0;
2191 
2192 		list_for_each_entry(pos, &head, list) {
2193 			errors[n].offset = pos->offset;
2194 			errors[n].length = pos->length;
2195 			nfs4_stateid_copy(&errors[n].stateid, &pos->stateid);
2196 			errors[n].errors[0].dev_id = pos->deviceid;
2197 			errors[n].errors[0].status = pos->status;
2198 			errors[n].errors[0].opnum = pos->opnum;
2199 			n++;
2200 			if (!list_is_last(&pos->list, &head) &&
2201 			    n < NFS42_LAYOUTERROR_MAX)
2202 				continue;
2203 			if (nfs42_proc_layouterror(lseg, errors, n) < 0)
2204 				break;
2205 			n = 0;
2206 		}
2207 		kfree(errors);
2208 	}
2209 	ff_layout_free_ds_ioerr(&head);
2210 }
2211 #else
2212 void
2213 ff_layout_send_layouterror(struct pnfs_layout_segment *lseg)
2214 {
2215 }
2216 #endif
2217 
2218 static int
2219 ff_layout_ntop4(const struct sockaddr *sap, char *buf, const size_t buflen)
2220 {
2221 	const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
2222 
2223 	return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
2224 }
2225 
2226 static size_t
2227 ff_layout_ntop6_noscopeid(const struct sockaddr *sap, char *buf,
2228 			  const int buflen)
2229 {
2230 	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
2231 	const struct in6_addr *addr = &sin6->sin6_addr;
2232 
2233 	/*
2234 	 * RFC 4291, Section 2.2.2
2235 	 *
2236 	 * Shorthanded ANY address
2237 	 */
2238 	if (ipv6_addr_any(addr))
2239 		return snprintf(buf, buflen, "::");
2240 
2241 	/*
2242 	 * RFC 4291, Section 2.2.2
2243 	 *
2244 	 * Shorthanded loopback address
2245 	 */
2246 	if (ipv6_addr_loopback(addr))
2247 		return snprintf(buf, buflen, "::1");
2248 
2249 	/*
2250 	 * RFC 4291, Section 2.2.3
2251 	 *
2252 	 * Special presentation address format for mapped v4
2253 	 * addresses.
2254 	 */
2255 	if (ipv6_addr_v4mapped(addr))
2256 		return snprintf(buf, buflen, "::ffff:%pI4",
2257 					&addr->s6_addr32[3]);
2258 
2259 	/*
2260 	 * RFC 4291, Section 2.2.1
2261 	 */
2262 	return snprintf(buf, buflen, "%pI6c", addr);
2263 }
2264 
2265 /* Derived from rpc_sockaddr2uaddr */
2266 static void
2267 ff_layout_encode_netaddr(struct xdr_stream *xdr, struct nfs4_pnfs_ds_addr *da)
2268 {
2269 	struct sockaddr *sap = (struct sockaddr *)&da->da_addr;
2270 	char portbuf[RPCBIND_MAXUADDRPLEN];
2271 	char addrbuf[RPCBIND_MAXUADDRLEN];
2272 	char *netid;
2273 	unsigned short port;
2274 	int len, netid_len;
2275 	__be32 *p;
2276 
2277 	switch (sap->sa_family) {
2278 	case AF_INET:
2279 		if (ff_layout_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
2280 			return;
2281 		port = ntohs(((struct sockaddr_in *)sap)->sin_port);
2282 		netid = "tcp";
2283 		netid_len = 3;
2284 		break;
2285 	case AF_INET6:
2286 		if (ff_layout_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
2287 			return;
2288 		port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
2289 		netid = "tcp6";
2290 		netid_len = 4;
2291 		break;
2292 	default:
2293 		/* we only support tcp and tcp6 */
2294 		WARN_ON_ONCE(1);
2295 		return;
2296 	}
2297 
2298 	snprintf(portbuf, sizeof(portbuf), ".%u.%u", port >> 8, port & 0xff);
2299 	len = strlcat(addrbuf, portbuf, sizeof(addrbuf));
2300 
2301 	p = xdr_reserve_space(xdr, 4 + netid_len);
2302 	xdr_encode_opaque(p, netid, netid_len);
2303 
2304 	p = xdr_reserve_space(xdr, 4 + len);
2305 	xdr_encode_opaque(p, addrbuf, len);
2306 }
2307 
2308 static void
2309 ff_layout_encode_nfstime(struct xdr_stream *xdr,
2310 			 ktime_t t)
2311 {
2312 	struct timespec64 ts;
2313 	__be32 *p;
2314 
2315 	p = xdr_reserve_space(xdr, 12);
2316 	ts = ktime_to_timespec64(t);
2317 	p = xdr_encode_hyper(p, ts.tv_sec);
2318 	*p++ = cpu_to_be32(ts.tv_nsec);
2319 }
2320 
2321 static void
2322 ff_layout_encode_io_latency(struct xdr_stream *xdr,
2323 			    struct nfs4_ff_io_stat *stat)
2324 {
2325 	__be32 *p;
2326 
2327 	p = xdr_reserve_space(xdr, 5 * 8);
2328 	p = xdr_encode_hyper(p, stat->ops_requested);
2329 	p = xdr_encode_hyper(p, stat->bytes_requested);
2330 	p = xdr_encode_hyper(p, stat->ops_completed);
2331 	p = xdr_encode_hyper(p, stat->bytes_completed);
2332 	p = xdr_encode_hyper(p, stat->bytes_not_delivered);
2333 	ff_layout_encode_nfstime(xdr, stat->total_busy_time);
2334 	ff_layout_encode_nfstime(xdr, stat->aggregate_completion_time);
2335 }
2336 
2337 static void
2338 ff_layout_encode_ff_layoutupdate(struct xdr_stream *xdr,
2339 			      const struct nfs42_layoutstat_devinfo *devinfo,
2340 			      struct nfs4_ff_layout_mirror *mirror)
2341 {
2342 	struct nfs4_pnfs_ds_addr *da;
2343 	struct nfs4_pnfs_ds *ds = mirror->mirror_ds->ds;
2344 	struct nfs_fh *fh = &mirror->fh_versions[0];
2345 	__be32 *p;
2346 
2347 	da = list_first_entry(&ds->ds_addrs, struct nfs4_pnfs_ds_addr, da_node);
2348 	dprintk("%s: DS %s: encoding address %s\n",
2349 		__func__, ds->ds_remotestr, da->da_remotestr);
2350 	/* netaddr4 */
2351 	ff_layout_encode_netaddr(xdr, da);
2352 	/* nfs_fh4 */
2353 	p = xdr_reserve_space(xdr, 4 + fh->size);
2354 	xdr_encode_opaque(p, fh->data, fh->size);
2355 	/* ff_io_latency4 read */
2356 	spin_lock(&mirror->lock);
2357 	ff_layout_encode_io_latency(xdr, &mirror->read_stat.io_stat);
2358 	/* ff_io_latency4 write */
2359 	ff_layout_encode_io_latency(xdr, &mirror->write_stat.io_stat);
2360 	spin_unlock(&mirror->lock);
2361 	/* nfstime4 */
2362 	ff_layout_encode_nfstime(xdr, ktime_sub(ktime_get(), mirror->start_time));
2363 	/* bool */
2364 	p = xdr_reserve_space(xdr, 4);
2365 	*p = cpu_to_be32(false);
2366 }
2367 
2368 static void
2369 ff_layout_encode_layoutstats(struct xdr_stream *xdr, const void *args,
2370 			     const struct nfs4_xdr_opaque_data *opaque)
2371 {
2372 	struct nfs42_layoutstat_devinfo *devinfo = container_of(opaque,
2373 			struct nfs42_layoutstat_devinfo, ld_private);
2374 	__be32 *start;
2375 
2376 	/* layoutupdate length */
2377 	start = xdr_reserve_space(xdr, 4);
2378 	ff_layout_encode_ff_layoutupdate(xdr, devinfo, opaque->data);
2379 
2380 	*start = cpu_to_be32((xdr->p - start - 1) * 4);
2381 }
2382 
2383 static void
2384 ff_layout_free_layoutstats(struct nfs4_xdr_opaque_data *opaque)
2385 {
2386 	struct nfs4_ff_layout_mirror *mirror = opaque->data;
2387 
2388 	ff_layout_put_mirror(mirror);
2389 }
2390 
2391 static const struct nfs4_xdr_opaque_ops layoutstat_ops = {
2392 	.encode = ff_layout_encode_layoutstats,
2393 	.free	= ff_layout_free_layoutstats,
2394 };
2395 
2396 static int
2397 ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
2398 			       struct nfs42_layoutstat_devinfo *devinfo,
2399 			       int dev_limit)
2400 {
2401 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
2402 	struct nfs4_ff_layout_mirror *mirror;
2403 	struct nfs4_deviceid_node *dev;
2404 	int i = 0;
2405 
2406 	list_for_each_entry(mirror, &ff_layout->mirrors, mirrors) {
2407 		if (i >= dev_limit)
2408 			break;
2409 		if (IS_ERR_OR_NULL(mirror->mirror_ds))
2410 			continue;
2411 		if (!test_and_clear_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags))
2412 			continue;
2413 		/* mirror refcount put in cleanup_layoutstats */
2414 		if (!refcount_inc_not_zero(&mirror->ref))
2415 			continue;
2416 		dev = &mirror->mirror_ds->id_node;
2417 		memcpy(&devinfo->dev_id, &dev->deviceid, NFS4_DEVICEID4_SIZE);
2418 		devinfo->offset = 0;
2419 		devinfo->length = NFS4_MAX_UINT64;
2420 		spin_lock(&mirror->lock);
2421 		devinfo->read_count = mirror->read_stat.io_stat.ops_completed;
2422 		devinfo->read_bytes = mirror->read_stat.io_stat.bytes_completed;
2423 		devinfo->write_count = mirror->write_stat.io_stat.ops_completed;
2424 		devinfo->write_bytes = mirror->write_stat.io_stat.bytes_completed;
2425 		spin_unlock(&mirror->lock);
2426 		devinfo->layout_type = LAYOUT_FLEX_FILES;
2427 		devinfo->ld_private.ops = &layoutstat_ops;
2428 		devinfo->ld_private.data = mirror;
2429 
2430 		devinfo++;
2431 		i++;
2432 	}
2433 	return i;
2434 }
2435 
2436 static int
2437 ff_layout_prepare_layoutstats(struct nfs42_layoutstat_args *args)
2438 {
2439 	struct nfs4_flexfile_layout *ff_layout;
2440 	const int dev_count = PNFS_LAYOUTSTATS_MAXDEV;
2441 
2442 	/* For now, send at most PNFS_LAYOUTSTATS_MAXDEV statistics */
2443 	args->devinfo = kmalloc_array(dev_count, sizeof(*args->devinfo), GFP_NOIO);
2444 	if (!args->devinfo)
2445 		return -ENOMEM;
2446 
2447 	spin_lock(&args->inode->i_lock);
2448 	ff_layout = FF_LAYOUT_FROM_HDR(NFS_I(args->inode)->layout);
2449 	args->num_dev = ff_layout_mirror_prepare_stats(&ff_layout->generic_hdr,
2450 			&args->devinfo[0], dev_count);
2451 	spin_unlock(&args->inode->i_lock);
2452 	if (!args->num_dev) {
2453 		kfree(args->devinfo);
2454 		args->devinfo = NULL;
2455 		return -ENOENT;
2456 	}
2457 
2458 	return 0;
2459 }
2460 
2461 static int
2462 ff_layout_set_layoutdriver(struct nfs_server *server,
2463 		const struct nfs_fh *dummy)
2464 {
2465 #if IS_ENABLED(CONFIG_NFS_V4_2)
2466 	server->caps |= NFS_CAP_LAYOUTSTATS;
2467 #endif
2468 	return 0;
2469 }
2470 
2471 static const struct pnfs_commit_ops ff_layout_commit_ops = {
2472 	.setup_ds_info		= ff_layout_setup_ds_info,
2473 	.release_ds_info	= ff_layout_release_ds_info,
2474 	.mark_request_commit	= pnfs_layout_mark_request_commit,
2475 	.clear_request_commit	= pnfs_generic_clear_request_commit,
2476 	.scan_commit_lists	= pnfs_generic_scan_commit_lists,
2477 	.recover_commit_reqs	= pnfs_generic_recover_commit_reqs,
2478 	.commit_pagelist	= ff_layout_commit_pagelist,
2479 };
2480 
2481 static struct pnfs_layoutdriver_type flexfilelayout_type = {
2482 	.id			= LAYOUT_FLEX_FILES,
2483 	.name			= "LAYOUT_FLEX_FILES",
2484 	.owner			= THIS_MODULE,
2485 	.flags			= PNFS_LAYOUTGET_ON_OPEN,
2486 	.max_layoutget_response	= 4096, /* 1 page or so... */
2487 	.set_layoutdriver	= ff_layout_set_layoutdriver,
2488 	.alloc_layout_hdr	= ff_layout_alloc_layout_hdr,
2489 	.free_layout_hdr	= ff_layout_free_layout_hdr,
2490 	.alloc_lseg		= ff_layout_alloc_lseg,
2491 	.free_lseg		= ff_layout_free_lseg,
2492 	.add_lseg		= ff_layout_add_lseg,
2493 	.pg_read_ops		= &ff_layout_pg_read_ops,
2494 	.pg_write_ops		= &ff_layout_pg_write_ops,
2495 	.get_ds_info		= ff_layout_get_ds_info,
2496 	.free_deviceid_node	= ff_layout_free_deviceid_node,
2497 	.read_pagelist		= ff_layout_read_pagelist,
2498 	.write_pagelist		= ff_layout_write_pagelist,
2499 	.alloc_deviceid_node    = ff_layout_alloc_deviceid_node,
2500 	.prepare_layoutreturn   = ff_layout_prepare_layoutreturn,
2501 	.sync			= pnfs_nfs_generic_sync,
2502 	.prepare_layoutstats	= ff_layout_prepare_layoutstats,
2503 };
2504 
2505 static int __init nfs4flexfilelayout_init(void)
2506 {
2507 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Registering...\n",
2508 	       __func__);
2509 	return pnfs_register_layoutdriver(&flexfilelayout_type);
2510 }
2511 
2512 static void __exit nfs4flexfilelayout_exit(void)
2513 {
2514 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Unregistering...\n",
2515 	       __func__);
2516 	pnfs_unregister_layoutdriver(&flexfilelayout_type);
2517 }
2518 
2519 MODULE_ALIAS("nfs-layouttype4-4");
2520 
2521 MODULE_LICENSE("GPL");
2522 MODULE_DESCRIPTION("The NFSv4 flexfile layout driver");
2523 
2524 module_init(nfs4flexfilelayout_init);
2525 module_exit(nfs4flexfilelayout_exit);
2526 
2527 module_param(io_maxretrans, ushort, 0644);
2528 MODULE_PARM_DESC(io_maxretrans, "The  number of times the NFSv4.1 client "
2529 			"retries an I/O request before returning an error. ");
2530