1 /*
2  * Module for pnfs flexfile layout driver.
3  *
4  * Copyright (c) 2014, Primary Data, Inc. All rights reserved.
5  *
6  * Tao Peng <bergwolf@primarydata.com>
7  */
8 
9 #include <linux/nfs_fs.h>
10 #include <linux/nfs_page.h>
11 #include <linux/module.h>
12 
13 #include <linux/sunrpc/metrics.h>
14 
15 #include "flexfilelayout.h"
16 #include "../nfs4session.h"
17 #include "../nfs4idmap.h"
18 #include "../internal.h"
19 #include "../delegation.h"
20 #include "../nfs4trace.h"
21 #include "../iostat.h"
22 #include "../nfs.h"
23 #include "../nfs42.h"
24 
25 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
26 
27 #define FF_LAYOUT_POLL_RETRY_MAX     (15*HZ)
28 
29 static struct group_info	*ff_zero_group;
30 
31 static struct pnfs_layout_hdr *
32 ff_layout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags)
33 {
34 	struct nfs4_flexfile_layout *ffl;
35 
36 	ffl = kzalloc(sizeof(*ffl), gfp_flags);
37 	if (ffl) {
38 		INIT_LIST_HEAD(&ffl->error_list);
39 		INIT_LIST_HEAD(&ffl->mirrors);
40 		ffl->last_report_time = ktime_get();
41 		return &ffl->generic_hdr;
42 	} else
43 		return NULL;
44 }
45 
46 static void
47 ff_layout_free_layout_hdr(struct pnfs_layout_hdr *lo)
48 {
49 	struct nfs4_ff_layout_ds_err *err, *n;
50 
51 	list_for_each_entry_safe(err, n, &FF_LAYOUT_FROM_HDR(lo)->error_list,
52 				 list) {
53 		list_del(&err->list);
54 		kfree(err);
55 	}
56 	kfree(FF_LAYOUT_FROM_HDR(lo));
57 }
58 
59 static int decode_pnfs_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
60 {
61 	__be32 *p;
62 
63 	p = xdr_inline_decode(xdr, NFS4_STATEID_SIZE);
64 	if (unlikely(p == NULL))
65 		return -ENOBUFS;
66 	stateid->type = NFS4_PNFS_DS_STATEID_TYPE;
67 	memcpy(stateid->data, p, NFS4_STATEID_SIZE);
68 	dprintk("%s: stateid id= [%x%x%x%x]\n", __func__,
69 		p[0], p[1], p[2], p[3]);
70 	return 0;
71 }
72 
73 static int decode_deviceid(struct xdr_stream *xdr, struct nfs4_deviceid *devid)
74 {
75 	__be32 *p;
76 
77 	p = xdr_inline_decode(xdr, NFS4_DEVICEID4_SIZE);
78 	if (unlikely(!p))
79 		return -ENOBUFS;
80 	memcpy(devid, p, NFS4_DEVICEID4_SIZE);
81 	nfs4_print_deviceid(devid);
82 	return 0;
83 }
84 
85 static int decode_nfs_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
86 {
87 	__be32 *p;
88 
89 	p = xdr_inline_decode(xdr, 4);
90 	if (unlikely(!p))
91 		return -ENOBUFS;
92 	fh->size = be32_to_cpup(p++);
93 	if (fh->size > sizeof(struct nfs_fh)) {
94 		printk(KERN_ERR "NFS flexfiles: Too big fh received %d\n",
95 		       fh->size);
96 		return -EOVERFLOW;
97 	}
98 	/* fh.data */
99 	p = xdr_inline_decode(xdr, fh->size);
100 	if (unlikely(!p))
101 		return -ENOBUFS;
102 	memcpy(&fh->data, p, fh->size);
103 	dprintk("%s: fh len %d\n", __func__, fh->size);
104 
105 	return 0;
106 }
107 
108 /*
109  * Currently only stringified uids and gids are accepted.
110  * I.e., kerberos is not supported to the DSes, so no pricipals.
111  *
112  * That means that one common function will suffice, but when
113  * principals are added, this should be split to accomodate
114  * calls to both nfs_map_name_to_uid() and nfs_map_group_to_gid().
115  */
116 static int
117 decode_name(struct xdr_stream *xdr, u32 *id)
118 {
119 	__be32 *p;
120 	int len;
121 
122 	/* opaque_length(4)*/
123 	p = xdr_inline_decode(xdr, 4);
124 	if (unlikely(!p))
125 		return -ENOBUFS;
126 	len = be32_to_cpup(p++);
127 	if (len < 0)
128 		return -EINVAL;
129 
130 	dprintk("%s: len %u\n", __func__, len);
131 
132 	/* opaque body */
133 	p = xdr_inline_decode(xdr, len);
134 	if (unlikely(!p))
135 		return -ENOBUFS;
136 
137 	if (!nfs_map_string_to_numeric((char *)p, len, id))
138 		return -EINVAL;
139 
140 	return 0;
141 }
142 
143 static bool ff_mirror_match_fh(const struct nfs4_ff_layout_mirror *m1,
144 		const struct nfs4_ff_layout_mirror *m2)
145 {
146 	int i, j;
147 
148 	if (m1->fh_versions_cnt != m2->fh_versions_cnt)
149 		return false;
150 	for (i = 0; i < m1->fh_versions_cnt; i++) {
151 		bool found_fh = false;
152 		for (j = 0; j < m2->fh_versions_cnt; j++) {
153 			if (nfs_compare_fh(&m1->fh_versions[i],
154 					&m2->fh_versions[j]) == 0) {
155 				found_fh = true;
156 				break;
157 			}
158 		}
159 		if (!found_fh)
160 			return false;
161 	}
162 	return true;
163 }
164 
165 static struct nfs4_ff_layout_mirror *
166 ff_layout_add_mirror(struct pnfs_layout_hdr *lo,
167 		struct nfs4_ff_layout_mirror *mirror)
168 {
169 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
170 	struct nfs4_ff_layout_mirror *pos;
171 	struct inode *inode = lo->plh_inode;
172 
173 	spin_lock(&inode->i_lock);
174 	list_for_each_entry(pos, &ff_layout->mirrors, mirrors) {
175 		if (mirror->mirror_ds != pos->mirror_ds)
176 			continue;
177 		if (!ff_mirror_match_fh(mirror, pos))
178 			continue;
179 		if (atomic_inc_not_zero(&pos->ref)) {
180 			spin_unlock(&inode->i_lock);
181 			return pos;
182 		}
183 	}
184 	list_add(&mirror->mirrors, &ff_layout->mirrors);
185 	mirror->layout = lo;
186 	spin_unlock(&inode->i_lock);
187 	return mirror;
188 }
189 
190 static void
191 ff_layout_remove_mirror(struct nfs4_ff_layout_mirror *mirror)
192 {
193 	struct inode *inode;
194 	if (mirror->layout == NULL)
195 		return;
196 	inode = mirror->layout->plh_inode;
197 	spin_lock(&inode->i_lock);
198 	list_del(&mirror->mirrors);
199 	spin_unlock(&inode->i_lock);
200 	mirror->layout = NULL;
201 }
202 
203 static struct nfs4_ff_layout_mirror *ff_layout_alloc_mirror(gfp_t gfp_flags)
204 {
205 	struct nfs4_ff_layout_mirror *mirror;
206 
207 	mirror = kzalloc(sizeof(*mirror), gfp_flags);
208 	if (mirror != NULL) {
209 		spin_lock_init(&mirror->lock);
210 		atomic_set(&mirror->ref, 1);
211 		INIT_LIST_HEAD(&mirror->mirrors);
212 	}
213 	return mirror;
214 }
215 
216 static void ff_layout_free_mirror(struct nfs4_ff_layout_mirror *mirror)
217 {
218 	struct rpc_cred	*cred;
219 
220 	ff_layout_remove_mirror(mirror);
221 	kfree(mirror->fh_versions);
222 	cred = rcu_access_pointer(mirror->ro_cred);
223 	if (cred)
224 		put_rpccred(cred);
225 	cred = rcu_access_pointer(mirror->rw_cred);
226 	if (cred)
227 		put_rpccred(cred);
228 	nfs4_ff_layout_put_deviceid(mirror->mirror_ds);
229 	kfree(mirror);
230 }
231 
232 static void ff_layout_put_mirror(struct nfs4_ff_layout_mirror *mirror)
233 {
234 	if (mirror != NULL && atomic_dec_and_test(&mirror->ref))
235 		ff_layout_free_mirror(mirror);
236 }
237 
238 static void ff_layout_free_mirror_array(struct nfs4_ff_layout_segment *fls)
239 {
240 	int i;
241 
242 	if (fls->mirror_array) {
243 		for (i = 0; i < fls->mirror_array_cnt; i++) {
244 			/* normally mirror_ds is freed in
245 			 * .free_deviceid_node but we still do it here
246 			 * for .alloc_lseg error path */
247 			ff_layout_put_mirror(fls->mirror_array[i]);
248 		}
249 		kfree(fls->mirror_array);
250 		fls->mirror_array = NULL;
251 	}
252 }
253 
254 static int ff_layout_check_layout(struct nfs4_layoutget_res *lgr)
255 {
256 	int ret = 0;
257 
258 	dprintk("--> %s\n", __func__);
259 
260 	/* FIXME: remove this check when layout segment support is added */
261 	if (lgr->range.offset != 0 ||
262 	    lgr->range.length != NFS4_MAX_UINT64) {
263 		dprintk("%s Only whole file layouts supported. Use MDS i/o\n",
264 			__func__);
265 		ret = -EINVAL;
266 	}
267 
268 	dprintk("--> %s returns %d\n", __func__, ret);
269 	return ret;
270 }
271 
272 static void _ff_layout_free_lseg(struct nfs4_ff_layout_segment *fls)
273 {
274 	if (fls) {
275 		ff_layout_free_mirror_array(fls);
276 		kfree(fls);
277 	}
278 }
279 
280 static bool
281 ff_lseg_range_is_after(const struct pnfs_layout_range *l1,
282 		const struct pnfs_layout_range *l2)
283 {
284 	u64 end1, end2;
285 
286 	if (l1->iomode != l2->iomode)
287 		return l1->iomode != IOMODE_READ;
288 	end1 = pnfs_calc_offset_end(l1->offset, l1->length);
289 	end2 = pnfs_calc_offset_end(l2->offset, l2->length);
290 	if (end1 < l2->offset)
291 		return false;
292 	if (end2 < l1->offset)
293 		return true;
294 	return l2->offset <= l1->offset;
295 }
296 
297 static bool
298 ff_lseg_merge(struct pnfs_layout_segment *new,
299 		struct pnfs_layout_segment *old)
300 {
301 	u64 new_end, old_end;
302 
303 	if (test_bit(NFS_LSEG_LAYOUTRETURN, &old->pls_flags))
304 		return false;
305 	if (new->pls_range.iomode != old->pls_range.iomode)
306 		return false;
307 	old_end = pnfs_calc_offset_end(old->pls_range.offset,
308 			old->pls_range.length);
309 	if (old_end < new->pls_range.offset)
310 		return false;
311 	new_end = pnfs_calc_offset_end(new->pls_range.offset,
312 			new->pls_range.length);
313 	if (new_end < old->pls_range.offset)
314 		return false;
315 
316 	/* Mergeable: copy info from 'old' to 'new' */
317 	if (new_end < old_end)
318 		new_end = old_end;
319 	if (new->pls_range.offset < old->pls_range.offset)
320 		new->pls_range.offset = old->pls_range.offset;
321 	new->pls_range.length = pnfs_calc_offset_length(new->pls_range.offset,
322 			new_end);
323 	if (test_bit(NFS_LSEG_ROC, &old->pls_flags))
324 		set_bit(NFS_LSEG_ROC, &new->pls_flags);
325 	return true;
326 }
327 
328 static void
329 ff_layout_add_lseg(struct pnfs_layout_hdr *lo,
330 		struct pnfs_layout_segment *lseg,
331 		struct list_head *free_me)
332 {
333 	pnfs_generic_layout_insert_lseg(lo, lseg,
334 			ff_lseg_range_is_after,
335 			ff_lseg_merge,
336 			free_me);
337 }
338 
339 static void ff_layout_sort_mirrors(struct nfs4_ff_layout_segment *fls)
340 {
341 	int i, j;
342 
343 	for (i = 0; i < fls->mirror_array_cnt - 1; i++) {
344 		for (j = i + 1; j < fls->mirror_array_cnt; j++)
345 			if (fls->mirror_array[i]->efficiency <
346 			    fls->mirror_array[j]->efficiency)
347 				swap(fls->mirror_array[i],
348 				     fls->mirror_array[j]);
349 	}
350 }
351 
352 static void ff_layout_mark_devices_valid(struct nfs4_ff_layout_segment *fls)
353 {
354 	struct nfs4_deviceid_node *node;
355 	int i;
356 
357 	if (!(fls->flags & FF_FLAGS_NO_IO_THRU_MDS))
358 		return;
359 	for (i = 0; i < fls->mirror_array_cnt; i++) {
360 		node = &fls->mirror_array[i]->mirror_ds->id_node;
361 		clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
362 	}
363 }
364 
365 static struct pnfs_layout_segment *
366 ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh,
367 		     struct nfs4_layoutget_res *lgr,
368 		     gfp_t gfp_flags)
369 {
370 	struct pnfs_layout_segment *ret;
371 	struct nfs4_ff_layout_segment *fls = NULL;
372 	struct xdr_stream stream;
373 	struct xdr_buf buf;
374 	struct page *scratch;
375 	u64 stripe_unit;
376 	u32 mirror_array_cnt;
377 	__be32 *p;
378 	int i, rc;
379 
380 	dprintk("--> %s\n", __func__);
381 	scratch = alloc_page(gfp_flags);
382 	if (!scratch)
383 		return ERR_PTR(-ENOMEM);
384 
385 	xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages,
386 			      lgr->layoutp->len);
387 	xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
388 
389 	/* stripe unit and mirror_array_cnt */
390 	rc = -EIO;
391 	p = xdr_inline_decode(&stream, 8 + 4);
392 	if (!p)
393 		goto out_err_free;
394 
395 	p = xdr_decode_hyper(p, &stripe_unit);
396 	mirror_array_cnt = be32_to_cpup(p++);
397 	dprintk("%s: stripe_unit=%llu mirror_array_cnt=%u\n", __func__,
398 		stripe_unit, mirror_array_cnt);
399 
400 	if (mirror_array_cnt > NFS4_FLEXFILE_LAYOUT_MAX_MIRROR_CNT ||
401 	    mirror_array_cnt == 0)
402 		goto out_err_free;
403 
404 	rc = -ENOMEM;
405 	fls = kzalloc(sizeof(*fls), gfp_flags);
406 	if (!fls)
407 		goto out_err_free;
408 
409 	fls->mirror_array_cnt = mirror_array_cnt;
410 	fls->stripe_unit = stripe_unit;
411 	fls->mirror_array = kcalloc(fls->mirror_array_cnt,
412 				    sizeof(fls->mirror_array[0]), gfp_flags);
413 	if (fls->mirror_array == NULL)
414 		goto out_err_free;
415 
416 	for (i = 0; i < fls->mirror_array_cnt; i++) {
417 		struct nfs4_ff_layout_mirror *mirror;
418 		struct nfs4_deviceid devid;
419 		struct nfs4_deviceid_node *idnode;
420 		struct auth_cred acred = { .group_info = ff_zero_group };
421 		struct rpc_cred	__rcu *cred;
422 		u32 ds_count, fh_count, id;
423 		int j;
424 
425 		rc = -EIO;
426 		p = xdr_inline_decode(&stream, 4);
427 		if (!p)
428 			goto out_err_free;
429 		ds_count = be32_to_cpup(p);
430 
431 		/* FIXME: allow for striping? */
432 		if (ds_count != 1)
433 			goto out_err_free;
434 
435 		fls->mirror_array[i] = ff_layout_alloc_mirror(gfp_flags);
436 		if (fls->mirror_array[i] == NULL) {
437 			rc = -ENOMEM;
438 			goto out_err_free;
439 		}
440 
441 		fls->mirror_array[i]->ds_count = ds_count;
442 
443 		/* deviceid */
444 		rc = decode_deviceid(&stream, &devid);
445 		if (rc)
446 			goto out_err_free;
447 
448 		idnode = nfs4_find_get_deviceid(NFS_SERVER(lh->plh_inode),
449 						&devid, lh->plh_lc_cred,
450 						gfp_flags);
451 		/*
452 		 * upon success, mirror_ds is allocated by previous
453 		 * getdeviceinfo, or newly by .alloc_deviceid_node
454 		 * nfs4_find_get_deviceid failure is indeed getdeviceinfo falure
455 		 */
456 		if (idnode)
457 			fls->mirror_array[i]->mirror_ds =
458 				FF_LAYOUT_MIRROR_DS(idnode);
459 		else
460 			goto out_err_free;
461 
462 		/* efficiency */
463 		rc = -EIO;
464 		p = xdr_inline_decode(&stream, 4);
465 		if (!p)
466 			goto out_err_free;
467 		fls->mirror_array[i]->efficiency = be32_to_cpup(p);
468 
469 		/* stateid */
470 		rc = decode_pnfs_stateid(&stream, &fls->mirror_array[i]->stateid);
471 		if (rc)
472 			goto out_err_free;
473 
474 		/* fh */
475 		p = xdr_inline_decode(&stream, 4);
476 		if (!p)
477 			goto out_err_free;
478 		fh_count = be32_to_cpup(p);
479 
480 		fls->mirror_array[i]->fh_versions =
481 			kzalloc(fh_count * sizeof(struct nfs_fh),
482 				gfp_flags);
483 		if (fls->mirror_array[i]->fh_versions == NULL) {
484 			rc = -ENOMEM;
485 			goto out_err_free;
486 		}
487 
488 		for (j = 0; j < fh_count; j++) {
489 			rc = decode_nfs_fh(&stream,
490 					   &fls->mirror_array[i]->fh_versions[j]);
491 			if (rc)
492 				goto out_err_free;
493 		}
494 
495 		fls->mirror_array[i]->fh_versions_cnt = fh_count;
496 
497 		/* user */
498 		rc = decode_name(&stream, &id);
499 		if (rc)
500 			goto out_err_free;
501 
502 		acred.uid = make_kuid(&init_user_ns, id);
503 
504 		/* group */
505 		rc = decode_name(&stream, &id);
506 		if (rc)
507 			goto out_err_free;
508 
509 		acred.gid = make_kgid(&init_user_ns, id);
510 
511 		/* find the cred for it */
512 		rcu_assign_pointer(cred, rpc_lookup_generic_cred(&acred, 0, gfp_flags));
513 		if (IS_ERR(cred)) {
514 			rc = PTR_ERR(cred);
515 			goto out_err_free;
516 		}
517 
518 		if (lgr->range.iomode == IOMODE_READ)
519 			rcu_assign_pointer(fls->mirror_array[i]->ro_cred, cred);
520 		else
521 			rcu_assign_pointer(fls->mirror_array[i]->rw_cred, cred);
522 
523 		mirror = ff_layout_add_mirror(lh, fls->mirror_array[i]);
524 		if (mirror != fls->mirror_array[i]) {
525 			/* swap cred ptrs so free_mirror will clean up old */
526 			if (lgr->range.iomode == IOMODE_READ) {
527 				cred = xchg(&mirror->ro_cred, cred);
528 				rcu_assign_pointer(fls->mirror_array[i]->ro_cred, cred);
529 			} else {
530 				cred = xchg(&mirror->rw_cred, cred);
531 				rcu_assign_pointer(fls->mirror_array[i]->rw_cred, cred);
532 			}
533 			ff_layout_free_mirror(fls->mirror_array[i]);
534 			fls->mirror_array[i] = mirror;
535 		}
536 
537 		dprintk("%s: iomode %s uid %u gid %u\n", __func__,
538 			lgr->range.iomode == IOMODE_READ ? "READ" : "RW",
539 			from_kuid(&init_user_ns, acred.uid),
540 			from_kgid(&init_user_ns, acred.gid));
541 	}
542 
543 	p = xdr_inline_decode(&stream, 4);
544 	if (!p)
545 		goto out_sort_mirrors;
546 	fls->flags = be32_to_cpup(p);
547 
548 	p = xdr_inline_decode(&stream, 4);
549 	if (!p)
550 		goto out_sort_mirrors;
551 	for (i=0; i < fls->mirror_array_cnt; i++)
552 		fls->mirror_array[i]->report_interval = be32_to_cpup(p);
553 
554 out_sort_mirrors:
555 	ff_layout_sort_mirrors(fls);
556 	rc = ff_layout_check_layout(lgr);
557 	if (rc)
558 		goto out_err_free;
559 	ff_layout_mark_devices_valid(fls);
560 
561 	ret = &fls->generic_hdr;
562 	dprintk("<-- %s (success)\n", __func__);
563 out_free_page:
564 	__free_page(scratch);
565 	return ret;
566 out_err_free:
567 	_ff_layout_free_lseg(fls);
568 	ret = ERR_PTR(rc);
569 	dprintk("<-- %s (%d)\n", __func__, rc);
570 	goto out_free_page;
571 }
572 
573 static bool ff_layout_has_rw_segments(struct pnfs_layout_hdr *layout)
574 {
575 	struct pnfs_layout_segment *lseg;
576 
577 	list_for_each_entry(lseg, &layout->plh_segs, pls_list)
578 		if (lseg->pls_range.iomode == IOMODE_RW)
579 			return true;
580 
581 	return false;
582 }
583 
584 static void
585 ff_layout_free_lseg(struct pnfs_layout_segment *lseg)
586 {
587 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
588 
589 	dprintk("--> %s\n", __func__);
590 
591 	if (lseg->pls_range.iomode == IOMODE_RW) {
592 		struct nfs4_flexfile_layout *ffl;
593 		struct inode *inode;
594 
595 		ffl = FF_LAYOUT_FROM_HDR(lseg->pls_layout);
596 		inode = ffl->generic_hdr.plh_inode;
597 		spin_lock(&inode->i_lock);
598 		if (!ff_layout_has_rw_segments(lseg->pls_layout)) {
599 			ffl->commit_info.nbuckets = 0;
600 			kfree(ffl->commit_info.buckets);
601 			ffl->commit_info.buckets = NULL;
602 		}
603 		spin_unlock(&inode->i_lock);
604 	}
605 	_ff_layout_free_lseg(fls);
606 }
607 
608 /* Return 1 until we have multiple lsegs support */
609 static int
610 ff_layout_get_lseg_count(struct nfs4_ff_layout_segment *fls)
611 {
612 	return 1;
613 }
614 
615 static void
616 nfs4_ff_start_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
617 {
618 	/* first IO request? */
619 	if (atomic_inc_return(&timer->n_ops) == 1) {
620 		timer->start_time = now;
621 	}
622 }
623 
624 static ktime_t
625 nfs4_ff_end_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
626 {
627 	ktime_t start;
628 
629 	if (atomic_dec_return(&timer->n_ops) < 0)
630 		WARN_ON_ONCE(1);
631 
632 	start = timer->start_time;
633 	timer->start_time = now;
634 	return ktime_sub(now, start);
635 }
636 
637 static bool
638 nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_mirror *mirror,
639 			    struct nfs4_ff_layoutstat *layoutstat,
640 			    ktime_t now)
641 {
642 	static const ktime_t notime = {0};
643 	s64 report_interval = FF_LAYOUTSTATS_REPORT_INTERVAL;
644 	struct nfs4_flexfile_layout *ffl = FF_LAYOUT_FROM_HDR(mirror->layout);
645 
646 	nfs4_ff_start_busy_timer(&layoutstat->busy_timer, now);
647 	if (ktime_equal(mirror->start_time, notime))
648 		mirror->start_time = now;
649 	if (mirror->report_interval != 0)
650 		report_interval = (s64)mirror->report_interval * 1000LL;
651 	else if (layoutstats_timer != 0)
652 		report_interval = (s64)layoutstats_timer * 1000LL;
653 	if (ktime_to_ms(ktime_sub(now, ffl->last_report_time)) >=
654 			report_interval) {
655 		ffl->last_report_time = now;
656 		return true;
657 	}
658 
659 	return false;
660 }
661 
662 static void
663 nfs4_ff_layout_stat_io_update_requested(struct nfs4_ff_layoutstat *layoutstat,
664 		__u64 requested)
665 {
666 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
667 
668 	iostat->ops_requested++;
669 	iostat->bytes_requested += requested;
670 }
671 
672 static void
673 nfs4_ff_layout_stat_io_update_completed(struct nfs4_ff_layoutstat *layoutstat,
674 		__u64 requested,
675 		__u64 completed,
676 		ktime_t time_completed,
677 		ktime_t time_started)
678 {
679 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
680 	ktime_t completion_time = ktime_sub(time_completed, time_started);
681 	ktime_t timer;
682 
683 	iostat->ops_completed++;
684 	iostat->bytes_completed += completed;
685 	iostat->bytes_not_delivered += requested - completed;
686 
687 	timer = nfs4_ff_end_busy_timer(&layoutstat->busy_timer, time_completed);
688 	iostat->total_busy_time =
689 			ktime_add(iostat->total_busy_time, timer);
690 	iostat->aggregate_completion_time =
691 			ktime_add(iostat->aggregate_completion_time,
692 					completion_time);
693 }
694 
695 static void
696 nfs4_ff_layout_stat_io_start_read(struct inode *inode,
697 		struct nfs4_ff_layout_mirror *mirror,
698 		__u64 requested, ktime_t now)
699 {
700 	bool report;
701 
702 	spin_lock(&mirror->lock);
703 	report = nfs4_ff_layoutstat_start_io(mirror, &mirror->read_stat, now);
704 	nfs4_ff_layout_stat_io_update_requested(&mirror->read_stat, requested);
705 	spin_unlock(&mirror->lock);
706 
707 	if (report)
708 		pnfs_report_layoutstat(inode, GFP_KERNEL);
709 }
710 
711 static void
712 nfs4_ff_layout_stat_io_end_read(struct rpc_task *task,
713 		struct nfs4_ff_layout_mirror *mirror,
714 		__u64 requested,
715 		__u64 completed)
716 {
717 	spin_lock(&mirror->lock);
718 	nfs4_ff_layout_stat_io_update_completed(&mirror->read_stat,
719 			requested, completed,
720 			ktime_get(), task->tk_start);
721 	spin_unlock(&mirror->lock);
722 }
723 
724 static void
725 nfs4_ff_layout_stat_io_start_write(struct inode *inode,
726 		struct nfs4_ff_layout_mirror *mirror,
727 		__u64 requested, ktime_t now)
728 {
729 	bool report;
730 
731 	spin_lock(&mirror->lock);
732 	report = nfs4_ff_layoutstat_start_io(mirror , &mirror->write_stat, now);
733 	nfs4_ff_layout_stat_io_update_requested(&mirror->write_stat, requested);
734 	spin_unlock(&mirror->lock);
735 
736 	if (report)
737 		pnfs_report_layoutstat(inode, GFP_NOIO);
738 }
739 
740 static void
741 nfs4_ff_layout_stat_io_end_write(struct rpc_task *task,
742 		struct nfs4_ff_layout_mirror *mirror,
743 		__u64 requested,
744 		__u64 completed,
745 		enum nfs3_stable_how committed)
746 {
747 	if (committed == NFS_UNSTABLE)
748 		requested = completed = 0;
749 
750 	spin_lock(&mirror->lock);
751 	nfs4_ff_layout_stat_io_update_completed(&mirror->write_stat,
752 			requested, completed, ktime_get(), task->tk_start);
753 	spin_unlock(&mirror->lock);
754 }
755 
756 static int
757 ff_layout_alloc_commit_info(struct pnfs_layout_segment *lseg,
758 			    struct nfs_commit_info *cinfo,
759 			    gfp_t gfp_flags)
760 {
761 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
762 	struct pnfs_commit_bucket *buckets;
763 	int size;
764 
765 	if (cinfo->ds->nbuckets != 0) {
766 		/* This assumes there is only one RW lseg per file.
767 		 * To support multiple lseg per file, we need to
768 		 * change struct pnfs_commit_bucket to allow dynamic
769 		 * increasing nbuckets.
770 		 */
771 		return 0;
772 	}
773 
774 	size = ff_layout_get_lseg_count(fls) * FF_LAYOUT_MIRROR_COUNT(lseg);
775 
776 	buckets = kcalloc(size, sizeof(struct pnfs_commit_bucket),
777 			  gfp_flags);
778 	if (!buckets)
779 		return -ENOMEM;
780 	else {
781 		int i;
782 
783 		spin_lock(&cinfo->inode->i_lock);
784 		if (cinfo->ds->nbuckets != 0)
785 			kfree(buckets);
786 		else {
787 			cinfo->ds->buckets = buckets;
788 			cinfo->ds->nbuckets = size;
789 			for (i = 0; i < size; i++) {
790 				INIT_LIST_HEAD(&buckets[i].written);
791 				INIT_LIST_HEAD(&buckets[i].committing);
792 				/* mark direct verifier as unset */
793 				buckets[i].direct_verf.committed =
794 					NFS_INVALID_STABLE_HOW;
795 			}
796 		}
797 		spin_unlock(&cinfo->inode->i_lock);
798 		return 0;
799 	}
800 }
801 
802 static struct nfs4_pnfs_ds *
803 ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg,
804 				  int start_idx,
805 				  int *best_idx)
806 {
807 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
808 	struct nfs4_pnfs_ds *ds;
809 	bool fail_return = false;
810 	int idx;
811 
812 	/* mirrors are sorted by efficiency */
813 	for (idx = start_idx; idx < fls->mirror_array_cnt; idx++) {
814 		if (idx+1 == fls->mirror_array_cnt)
815 			fail_return = true;
816 		ds = nfs4_ff_layout_prepare_ds(lseg, idx, fail_return);
817 		if (ds) {
818 			*best_idx = idx;
819 			return ds;
820 		}
821 	}
822 
823 	return NULL;
824 }
825 
826 static void
827 ff_layout_pg_get_read(struct nfs_pageio_descriptor *pgio,
828 		      struct nfs_page *req,
829 		      bool strict_iomode)
830 {
831 retry_strict:
832 	pnfs_put_lseg(pgio->pg_lseg);
833 	pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
834 					   req->wb_context,
835 					   0,
836 					   NFS4_MAX_UINT64,
837 					   IOMODE_READ,
838 					   strict_iomode,
839 					   GFP_KERNEL);
840 	if (IS_ERR(pgio->pg_lseg)) {
841 		pgio->pg_error = PTR_ERR(pgio->pg_lseg);
842 		pgio->pg_lseg = NULL;
843 	}
844 
845 	/* If we don't have checking, do get a IOMODE_RW
846 	 * segment, and the server wants to avoid READs
847 	 * there, then retry!
848 	 */
849 	if (pgio->pg_lseg && !strict_iomode &&
850 	    ff_layout_avoid_read_on_rw(pgio->pg_lseg)) {
851 		strict_iomode = true;
852 		goto retry_strict;
853 	}
854 }
855 
856 static void
857 ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
858 			struct nfs_page *req)
859 {
860 	struct nfs_pgio_mirror *pgm;
861 	struct nfs4_ff_layout_mirror *mirror;
862 	struct nfs4_pnfs_ds *ds;
863 	int ds_idx;
864 
865 retry:
866 	/* Use full layout for now */
867 	if (!pgio->pg_lseg)
868 		ff_layout_pg_get_read(pgio, req, false);
869 	else if (ff_layout_avoid_read_on_rw(pgio->pg_lseg))
870 		ff_layout_pg_get_read(pgio, req, true);
871 
872 	/* If no lseg, fall back to read through mds */
873 	if (pgio->pg_lseg == NULL)
874 		goto out_mds;
875 
876 	ds = ff_layout_choose_best_ds_for_read(pgio->pg_lseg, 0, &ds_idx);
877 	if (!ds) {
878 		if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
879 			goto out_mds;
880 		pnfs_put_lseg(pgio->pg_lseg);
881 		pgio->pg_lseg = NULL;
882 		/* Sleep for 1 second before retrying */
883 		ssleep(1);
884 		goto retry;
885 	}
886 
887 	mirror = FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx);
888 
889 	pgio->pg_mirror_idx = ds_idx;
890 
891 	/* read always uses only one mirror - idx 0 for pgio layer */
892 	pgm = &pgio->pg_mirrors[0];
893 	pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].rsize;
894 
895 	return;
896 out_mds:
897 	pnfs_put_lseg(pgio->pg_lseg);
898 	pgio->pg_lseg = NULL;
899 	nfs_pageio_reset_read_mds(pgio);
900 }
901 
902 static void
903 ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
904 			struct nfs_page *req)
905 {
906 	struct nfs4_ff_layout_mirror *mirror;
907 	struct nfs_pgio_mirror *pgm;
908 	struct nfs_commit_info cinfo;
909 	struct nfs4_pnfs_ds *ds;
910 	int i;
911 	int status;
912 
913 retry:
914 	if (!pgio->pg_lseg) {
915 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
916 						   req->wb_context,
917 						   0,
918 						   NFS4_MAX_UINT64,
919 						   IOMODE_RW,
920 						   false,
921 						   GFP_NOFS);
922 		if (IS_ERR(pgio->pg_lseg)) {
923 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
924 			pgio->pg_lseg = NULL;
925 			return;
926 		}
927 	}
928 	/* If no lseg, fall back to write through mds */
929 	if (pgio->pg_lseg == NULL)
930 		goto out_mds;
931 
932 	nfs_init_cinfo(&cinfo, pgio->pg_inode, pgio->pg_dreq);
933 	status = ff_layout_alloc_commit_info(pgio->pg_lseg, &cinfo, GFP_NOFS);
934 	if (status < 0)
935 		goto out_mds;
936 
937 	/* Use a direct mapping of ds_idx to pgio mirror_idx */
938 	if (WARN_ON_ONCE(pgio->pg_mirror_count !=
939 	    FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg)))
940 		goto out_mds;
941 
942 	for (i = 0; i < pgio->pg_mirror_count; i++) {
943 		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, i, true);
944 		if (!ds) {
945 			if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
946 				goto out_mds;
947 			pnfs_put_lseg(pgio->pg_lseg);
948 			pgio->pg_lseg = NULL;
949 			/* Sleep for 1 second before retrying */
950 			ssleep(1);
951 			goto retry;
952 		}
953 		pgm = &pgio->pg_mirrors[i];
954 		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
955 		pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].wsize;
956 	}
957 
958 	return;
959 
960 out_mds:
961 	pnfs_put_lseg(pgio->pg_lseg);
962 	pgio->pg_lseg = NULL;
963 	nfs_pageio_reset_write_mds(pgio);
964 }
965 
966 static unsigned int
967 ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
968 				    struct nfs_page *req)
969 {
970 	if (!pgio->pg_lseg) {
971 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
972 						   req->wb_context,
973 						   0,
974 						   NFS4_MAX_UINT64,
975 						   IOMODE_RW,
976 						   false,
977 						   GFP_NOFS);
978 		if (IS_ERR(pgio->pg_lseg)) {
979 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
980 			pgio->pg_lseg = NULL;
981 			goto out;
982 		}
983 	}
984 	if (pgio->pg_lseg)
985 		return FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg);
986 
987 	/* no lseg means that pnfs is not in use, so no mirroring here */
988 	nfs_pageio_reset_write_mds(pgio);
989 out:
990 	return 1;
991 }
992 
993 static const struct nfs_pageio_ops ff_layout_pg_read_ops = {
994 	.pg_init = ff_layout_pg_init_read,
995 	.pg_test = pnfs_generic_pg_test,
996 	.pg_doio = pnfs_generic_pg_readpages,
997 	.pg_cleanup = pnfs_generic_pg_cleanup,
998 };
999 
1000 static const struct nfs_pageio_ops ff_layout_pg_write_ops = {
1001 	.pg_init = ff_layout_pg_init_write,
1002 	.pg_test = pnfs_generic_pg_test,
1003 	.pg_doio = pnfs_generic_pg_writepages,
1004 	.pg_get_mirror_count = ff_layout_pg_get_mirror_count_write,
1005 	.pg_cleanup = pnfs_generic_pg_cleanup,
1006 };
1007 
1008 static void ff_layout_reset_write(struct nfs_pgio_header *hdr, bool retry_pnfs)
1009 {
1010 	struct rpc_task *task = &hdr->task;
1011 
1012 	pnfs_layoutcommit_inode(hdr->inode, false);
1013 
1014 	if (retry_pnfs) {
1015 		dprintk("%s Reset task %5u for i/o through pNFS "
1016 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1017 			hdr->task.tk_pid,
1018 			hdr->inode->i_sb->s_id,
1019 			(unsigned long long)NFS_FILEID(hdr->inode),
1020 			hdr->args.count,
1021 			(unsigned long long)hdr->args.offset);
1022 
1023 		hdr->completion_ops->reschedule_io(hdr);
1024 		return;
1025 	}
1026 
1027 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1028 		dprintk("%s Reset task %5u for i/o through MDS "
1029 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1030 			hdr->task.tk_pid,
1031 			hdr->inode->i_sb->s_id,
1032 			(unsigned long long)NFS_FILEID(hdr->inode),
1033 			hdr->args.count,
1034 			(unsigned long long)hdr->args.offset);
1035 
1036 		task->tk_status = pnfs_write_done_resend_to_mds(hdr);
1037 	}
1038 }
1039 
1040 static void ff_layout_reset_read(struct nfs_pgio_header *hdr)
1041 {
1042 	struct rpc_task *task = &hdr->task;
1043 
1044 	pnfs_layoutcommit_inode(hdr->inode, false);
1045 
1046 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1047 		dprintk("%s Reset task %5u for i/o through MDS "
1048 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1049 			hdr->task.tk_pid,
1050 			hdr->inode->i_sb->s_id,
1051 			(unsigned long long)NFS_FILEID(hdr->inode),
1052 			hdr->args.count,
1053 			(unsigned long long)hdr->args.offset);
1054 
1055 		task->tk_status = pnfs_read_done_resend_to_mds(hdr);
1056 	}
1057 }
1058 
1059 static int ff_layout_async_handle_error_v4(struct rpc_task *task,
1060 					   struct nfs4_state *state,
1061 					   struct nfs_client *clp,
1062 					   struct pnfs_layout_segment *lseg,
1063 					   int idx)
1064 {
1065 	struct pnfs_layout_hdr *lo = lseg->pls_layout;
1066 	struct inode *inode = lo->plh_inode;
1067 	struct nfs_server *mds_server = NFS_SERVER(inode);
1068 
1069 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1070 	struct nfs_client *mds_client = mds_server->nfs_client;
1071 	struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
1072 
1073 	if (task->tk_status >= 0)
1074 		return 0;
1075 
1076 	switch (task->tk_status) {
1077 	/* MDS state errors */
1078 	case -NFS4ERR_DELEG_REVOKED:
1079 	case -NFS4ERR_ADMIN_REVOKED:
1080 	case -NFS4ERR_BAD_STATEID:
1081 		if (state == NULL)
1082 			break;
1083 		nfs_remove_bad_delegation(state->inode);
1084 	case -NFS4ERR_OPENMODE:
1085 		if (state == NULL)
1086 			break;
1087 		if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
1088 			goto out_bad_stateid;
1089 		goto wait_on_recovery;
1090 	case -NFS4ERR_EXPIRED:
1091 		if (state != NULL) {
1092 			if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
1093 				goto out_bad_stateid;
1094 		}
1095 		nfs4_schedule_lease_recovery(mds_client);
1096 		goto wait_on_recovery;
1097 	/* DS session errors */
1098 	case -NFS4ERR_BADSESSION:
1099 	case -NFS4ERR_BADSLOT:
1100 	case -NFS4ERR_BAD_HIGH_SLOT:
1101 	case -NFS4ERR_DEADSESSION:
1102 	case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
1103 	case -NFS4ERR_SEQ_FALSE_RETRY:
1104 	case -NFS4ERR_SEQ_MISORDERED:
1105 		dprintk("%s ERROR %d, Reset session. Exchangeid "
1106 			"flags 0x%x\n", __func__, task->tk_status,
1107 			clp->cl_exchange_flags);
1108 		nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
1109 		break;
1110 	case -NFS4ERR_DELAY:
1111 	case -NFS4ERR_GRACE:
1112 		rpc_delay(task, FF_LAYOUT_POLL_RETRY_MAX);
1113 		break;
1114 	case -NFS4ERR_RETRY_UNCACHED_REP:
1115 		break;
1116 	/* Invalidate Layout errors */
1117 	case -NFS4ERR_PNFS_NO_LAYOUT:
1118 	case -ESTALE:           /* mapped NFS4ERR_STALE */
1119 	case -EBADHANDLE:       /* mapped NFS4ERR_BADHANDLE */
1120 	case -EISDIR:           /* mapped NFS4ERR_ISDIR */
1121 	case -NFS4ERR_FHEXPIRED:
1122 	case -NFS4ERR_WRONG_TYPE:
1123 		dprintk("%s Invalid layout error %d\n", __func__,
1124 			task->tk_status);
1125 		/*
1126 		 * Destroy layout so new i/o will get a new layout.
1127 		 * Layout will not be destroyed until all current lseg
1128 		 * references are put. Mark layout as invalid to resend failed
1129 		 * i/o and all i/o waiting on the slot table to the MDS until
1130 		 * layout is destroyed and a new valid layout is obtained.
1131 		 */
1132 		pnfs_destroy_layout(NFS_I(inode));
1133 		rpc_wake_up(&tbl->slot_tbl_waitq);
1134 		goto reset;
1135 	/* RPC connection errors */
1136 	case -ECONNREFUSED:
1137 	case -EHOSTDOWN:
1138 	case -EHOSTUNREACH:
1139 	case -ENETUNREACH:
1140 	case -EIO:
1141 	case -ETIMEDOUT:
1142 	case -EPIPE:
1143 		dprintk("%s DS connection error %d\n", __func__,
1144 			task->tk_status);
1145 		nfs4_mark_deviceid_unavailable(devid);
1146 		rpc_wake_up(&tbl->slot_tbl_waitq);
1147 		/* fall through */
1148 	default:
1149 		if (ff_layout_avoid_mds_available_ds(lseg))
1150 			return -NFS4ERR_RESET_TO_PNFS;
1151 reset:
1152 		dprintk("%s Retry through MDS. Error %d\n", __func__,
1153 			task->tk_status);
1154 		return -NFS4ERR_RESET_TO_MDS;
1155 	}
1156 out:
1157 	task->tk_status = 0;
1158 	return -EAGAIN;
1159 out_bad_stateid:
1160 	task->tk_status = -EIO;
1161 	return 0;
1162 wait_on_recovery:
1163 	rpc_sleep_on(&mds_client->cl_rpcwaitq, task, NULL);
1164 	if (test_bit(NFS4CLNT_MANAGER_RUNNING, &mds_client->cl_state) == 0)
1165 		rpc_wake_up_queued_task(&mds_client->cl_rpcwaitq, task);
1166 	goto out;
1167 }
1168 
1169 /* Retry all errors through either pNFS or MDS except for -EJUKEBOX */
1170 static int ff_layout_async_handle_error_v3(struct rpc_task *task,
1171 					   struct pnfs_layout_segment *lseg,
1172 					   int idx)
1173 {
1174 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1175 
1176 	if (task->tk_status >= 0)
1177 		return 0;
1178 
1179 	switch (task->tk_status) {
1180 	/* File access problems. Don't mark the device as unavailable */
1181 	case -EACCES:
1182 	case -ESTALE:
1183 	case -EISDIR:
1184 	case -EBADHANDLE:
1185 	case -ELOOP:
1186 	case -ENOSPC:
1187 		break;
1188 	case -EJUKEBOX:
1189 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1190 		goto out_retry;
1191 	default:
1192 		dprintk("%s DS connection error %d\n", __func__,
1193 			task->tk_status);
1194 		nfs4_mark_deviceid_unavailable(devid);
1195 	}
1196 	/* FIXME: Need to prevent infinite looping here. */
1197 	return -NFS4ERR_RESET_TO_PNFS;
1198 out_retry:
1199 	task->tk_status = 0;
1200 	rpc_restart_call_prepare(task);
1201 	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
1202 	return -EAGAIN;
1203 }
1204 
1205 static int ff_layout_async_handle_error(struct rpc_task *task,
1206 					struct nfs4_state *state,
1207 					struct nfs_client *clp,
1208 					struct pnfs_layout_segment *lseg,
1209 					int idx)
1210 {
1211 	int vers = clp->cl_nfs_mod->rpc_vers->number;
1212 
1213 	switch (vers) {
1214 	case 3:
1215 		return ff_layout_async_handle_error_v3(task, lseg, idx);
1216 	case 4:
1217 		return ff_layout_async_handle_error_v4(task, state, clp,
1218 						       lseg, idx);
1219 	default:
1220 		/* should never happen */
1221 		WARN_ON_ONCE(1);
1222 		return 0;
1223 	}
1224 }
1225 
1226 static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg,
1227 					int idx, u64 offset, u64 length,
1228 					u32 status, int opnum, int error)
1229 {
1230 	struct nfs4_ff_layout_mirror *mirror;
1231 	int err;
1232 
1233 	if (status == 0) {
1234 		switch (error) {
1235 		case -ETIMEDOUT:
1236 		case -EPFNOSUPPORT:
1237 		case -EPROTONOSUPPORT:
1238 		case -EOPNOTSUPP:
1239 		case -ECONNREFUSED:
1240 		case -ECONNRESET:
1241 		case -EHOSTDOWN:
1242 		case -EHOSTUNREACH:
1243 		case -ENETUNREACH:
1244 		case -EADDRINUSE:
1245 		case -ENOBUFS:
1246 		case -EPIPE:
1247 		case -EPERM:
1248 			status = NFS4ERR_NXIO;
1249 			break;
1250 		case -EACCES:
1251 			status = NFS4ERR_ACCESS;
1252 			break;
1253 		default:
1254 			return;
1255 		}
1256 	}
1257 
1258 	switch (status) {
1259 	case NFS4ERR_DELAY:
1260 	case NFS4ERR_GRACE:
1261 		return;
1262 	default:
1263 		break;
1264 	}
1265 
1266 	mirror = FF_LAYOUT_COMP(lseg, idx);
1267 	err = ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),
1268 				       mirror, offset, length, status, opnum,
1269 				       GFP_NOIO);
1270 	pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode, lseg);
1271 	dprintk("%s: err %d op %d status %u\n", __func__, err, opnum, status);
1272 }
1273 
1274 /* NFS_PROTO call done callback routines */
1275 static int ff_layout_read_done_cb(struct rpc_task *task,
1276 				struct nfs_pgio_header *hdr)
1277 {
1278 	int err;
1279 
1280 	trace_nfs4_pnfs_read(hdr, task->tk_status);
1281 	if (task->tk_status < 0)
1282 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1283 					    hdr->args.offset, hdr->args.count,
1284 					    hdr->res.op_status, OP_READ,
1285 					    task->tk_status);
1286 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1287 					   hdr->ds_clp, hdr->lseg,
1288 					   hdr->pgio_mirror_idx);
1289 
1290 	switch (err) {
1291 	case -NFS4ERR_RESET_TO_PNFS:
1292 		if (ff_layout_choose_best_ds_for_read(hdr->lseg,
1293 					hdr->pgio_mirror_idx + 1,
1294 					&hdr->pgio_mirror_idx))
1295 			goto out_eagain;
1296 		pnfs_read_resend_pnfs(hdr);
1297 		return task->tk_status;
1298 	case -NFS4ERR_RESET_TO_MDS:
1299 		ff_layout_reset_read(hdr);
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 bool
1340 ff_layout_device_unavailable(struct pnfs_layout_segment *lseg, int idx)
1341 {
1342 	/* No mirroring for now */
1343 	struct nfs4_deviceid_node *node = FF_LAYOUT_DEVID_NODE(lseg, idx);
1344 
1345 	return ff_layout_test_devid_unavailable(node);
1346 }
1347 
1348 static void ff_layout_read_record_layoutstats_start(struct rpc_task *task,
1349 		struct nfs_pgio_header *hdr)
1350 {
1351 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1352 		return;
1353 	nfs4_ff_layout_stat_io_start_read(hdr->inode,
1354 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1355 			hdr->args.count,
1356 			task->tk_start);
1357 }
1358 
1359 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
1360 		struct nfs_pgio_header *hdr)
1361 {
1362 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1363 		return;
1364 	nfs4_ff_layout_stat_io_end_read(task,
1365 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1366 			hdr->args.count,
1367 			hdr->res.count);
1368 }
1369 
1370 static int ff_layout_read_prepare_common(struct rpc_task *task,
1371 					 struct nfs_pgio_header *hdr)
1372 {
1373 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1374 		rpc_exit(task, -EIO);
1375 		return -EIO;
1376 	}
1377 	if (ff_layout_device_unavailable(hdr->lseg, hdr->pgio_mirror_idx)) {
1378 		rpc_exit(task, -EHOSTDOWN);
1379 		return -EAGAIN;
1380 	}
1381 
1382 	ff_layout_read_record_layoutstats_start(task, hdr);
1383 	return 0;
1384 }
1385 
1386 /*
1387  * Call ops for the async read/write cases
1388  * In the case of dense layouts, the offset needs to be reset to its
1389  * original value.
1390  */
1391 static void ff_layout_read_prepare_v3(struct rpc_task *task, void *data)
1392 {
1393 	struct nfs_pgio_header *hdr = data;
1394 
1395 	if (ff_layout_read_prepare_common(task, hdr))
1396 		return;
1397 
1398 	rpc_call_start(task);
1399 }
1400 
1401 static int ff_layout_setup_sequence(struct nfs_client *ds_clp,
1402 				    struct nfs4_sequence_args *args,
1403 				    struct nfs4_sequence_res *res,
1404 				    struct rpc_task *task)
1405 {
1406 	if (ds_clp->cl_session)
1407 		return nfs41_setup_sequence(ds_clp->cl_session,
1408 					   args,
1409 					   res,
1410 					   task);
1411 	return nfs40_setup_sequence(ds_clp->cl_slot_tbl,
1412 				   args,
1413 				   res,
1414 				   task);
1415 }
1416 
1417 static void ff_layout_read_prepare_v4(struct rpc_task *task, void *data)
1418 {
1419 	struct nfs_pgio_header *hdr = data;
1420 
1421 	if (ff_layout_setup_sequence(hdr->ds_clp,
1422 				     &hdr->args.seq_args,
1423 				     &hdr->res.seq_res,
1424 				     task))
1425 		return;
1426 
1427 	if (ff_layout_read_prepare_common(task, hdr))
1428 		return;
1429 
1430 	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
1431 			hdr->args.lock_context, FMODE_READ) == -EIO)
1432 		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
1433 }
1434 
1435 static void ff_layout_read_call_done(struct rpc_task *task, void *data)
1436 {
1437 	struct nfs_pgio_header *hdr = data;
1438 
1439 	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
1440 
1441 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1442 	    task->tk_status == 0) {
1443 		nfs4_sequence_done(task, &hdr->res.seq_res);
1444 		return;
1445 	}
1446 
1447 	/* Note this may cause RPC to be resent */
1448 	hdr->mds_ops->rpc_call_done(task, hdr);
1449 }
1450 
1451 static void ff_layout_read_count_stats(struct rpc_task *task, void *data)
1452 {
1453 	struct nfs_pgio_header *hdr = data;
1454 
1455 	ff_layout_read_record_layoutstats_done(task, hdr);
1456 	rpc_count_iostats_metrics(task,
1457 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_READ]);
1458 }
1459 
1460 static void ff_layout_read_release(void *data)
1461 {
1462 	struct nfs_pgio_header *hdr = data;
1463 
1464 	ff_layout_read_record_layoutstats_done(&hdr->task, hdr);
1465 	pnfs_generic_rw_release(data);
1466 }
1467 
1468 
1469 static int ff_layout_write_done_cb(struct rpc_task *task,
1470 				struct nfs_pgio_header *hdr)
1471 {
1472 	loff_t end_offs = 0;
1473 	int err;
1474 
1475 	trace_nfs4_pnfs_write(hdr, task->tk_status);
1476 	if (task->tk_status < 0)
1477 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1478 					    hdr->args.offset, hdr->args.count,
1479 					    hdr->res.op_status, OP_WRITE,
1480 					    task->tk_status);
1481 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1482 					   hdr->ds_clp, hdr->lseg,
1483 					   hdr->pgio_mirror_idx);
1484 
1485 	switch (err) {
1486 	case -NFS4ERR_RESET_TO_PNFS:
1487 		ff_layout_reset_write(hdr, true);
1488 		return task->tk_status;
1489 	case -NFS4ERR_RESET_TO_MDS:
1490 		ff_layout_reset_write(hdr, false);
1491 		return task->tk_status;
1492 	case -EAGAIN:
1493 		return -EAGAIN;
1494 	}
1495 
1496 	if (hdr->res.verf->committed == NFS_FILE_SYNC ||
1497 	    hdr->res.verf->committed == NFS_DATA_SYNC)
1498 		end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
1499 
1500 	/* Note: if the write is unstable, don't set end_offs until commit */
1501 	ff_layout_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
1502 
1503 	/* zero out fattr since we don't care DS attr at all */
1504 	hdr->fattr.valid = 0;
1505 	if (task->tk_status >= 0)
1506 		nfs_writeback_update_inode(hdr);
1507 
1508 	return 0;
1509 }
1510 
1511 static int ff_layout_commit_done_cb(struct rpc_task *task,
1512 				     struct nfs_commit_data *data)
1513 {
1514 	int err;
1515 
1516 	trace_nfs4_pnfs_commit_ds(data, task->tk_status);
1517 	if (task->tk_status < 0)
1518 		ff_layout_io_track_ds_error(data->lseg, data->ds_commit_index,
1519 					    data->args.offset, data->args.count,
1520 					    data->res.op_status, OP_COMMIT,
1521 					    task->tk_status);
1522 	err = ff_layout_async_handle_error(task, NULL, data->ds_clp,
1523 					   data->lseg, data->ds_commit_index);
1524 
1525 	switch (err) {
1526 	case -NFS4ERR_RESET_TO_PNFS:
1527 		pnfs_generic_prepare_to_resend_writes(data);
1528 		return -EAGAIN;
1529 	case -NFS4ERR_RESET_TO_MDS:
1530 		pnfs_generic_prepare_to_resend_writes(data);
1531 		return -EAGAIN;
1532 	case -EAGAIN:
1533 		rpc_restart_call_prepare(task);
1534 		return -EAGAIN;
1535 	}
1536 
1537 	ff_layout_set_layoutcommit(data->inode, data->lseg, data->lwb);
1538 
1539 	return 0;
1540 }
1541 
1542 static void ff_layout_write_record_layoutstats_start(struct rpc_task *task,
1543 		struct nfs_pgio_header *hdr)
1544 {
1545 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1546 		return;
1547 	nfs4_ff_layout_stat_io_start_write(hdr->inode,
1548 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1549 			hdr->args.count,
1550 			task->tk_start);
1551 }
1552 
1553 static void ff_layout_write_record_layoutstats_done(struct rpc_task *task,
1554 		struct nfs_pgio_header *hdr)
1555 {
1556 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1557 		return;
1558 	nfs4_ff_layout_stat_io_end_write(task,
1559 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1560 			hdr->args.count, hdr->res.count,
1561 			hdr->res.verf->committed);
1562 }
1563 
1564 static int ff_layout_write_prepare_common(struct rpc_task *task,
1565 					  struct nfs_pgio_header *hdr)
1566 {
1567 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1568 		rpc_exit(task, -EIO);
1569 		return -EIO;
1570 	}
1571 
1572 	if (ff_layout_device_unavailable(hdr->lseg, hdr->pgio_mirror_idx)) {
1573 		rpc_exit(task, -EHOSTDOWN);
1574 		return -EAGAIN;
1575 	}
1576 
1577 	ff_layout_write_record_layoutstats_start(task, hdr);
1578 	return 0;
1579 }
1580 
1581 static void ff_layout_write_prepare_v3(struct rpc_task *task, void *data)
1582 {
1583 	struct nfs_pgio_header *hdr = data;
1584 
1585 	if (ff_layout_write_prepare_common(task, hdr))
1586 		return;
1587 
1588 	rpc_call_start(task);
1589 }
1590 
1591 static void ff_layout_write_prepare_v4(struct rpc_task *task, void *data)
1592 {
1593 	struct nfs_pgio_header *hdr = data;
1594 
1595 	if (ff_layout_setup_sequence(hdr->ds_clp,
1596 				     &hdr->args.seq_args,
1597 				     &hdr->res.seq_res,
1598 				     task))
1599 		return;
1600 
1601 	if (ff_layout_write_prepare_common(task, hdr))
1602 		return;
1603 
1604 	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
1605 			hdr->args.lock_context, FMODE_WRITE) == -EIO)
1606 		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
1607 }
1608 
1609 static void ff_layout_write_call_done(struct rpc_task *task, void *data)
1610 {
1611 	struct nfs_pgio_header *hdr = data;
1612 
1613 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1614 	    task->tk_status == 0) {
1615 		nfs4_sequence_done(task, &hdr->res.seq_res);
1616 		return;
1617 	}
1618 
1619 	/* Note this may cause RPC to be resent */
1620 	hdr->mds_ops->rpc_call_done(task, hdr);
1621 }
1622 
1623 static void ff_layout_write_count_stats(struct rpc_task *task, void *data)
1624 {
1625 	struct nfs_pgio_header *hdr = data;
1626 
1627 	ff_layout_write_record_layoutstats_done(task, hdr);
1628 	rpc_count_iostats_metrics(task,
1629 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_WRITE]);
1630 }
1631 
1632 static void ff_layout_write_release(void *data)
1633 {
1634 	struct nfs_pgio_header *hdr = data;
1635 
1636 	ff_layout_write_record_layoutstats_done(&hdr->task, hdr);
1637 	pnfs_generic_rw_release(data);
1638 }
1639 
1640 static void ff_layout_commit_record_layoutstats_start(struct rpc_task *task,
1641 		struct nfs_commit_data *cdata)
1642 {
1643 	if (test_and_set_bit(NFS_IOHDR_STAT, &cdata->flags))
1644 		return;
1645 	nfs4_ff_layout_stat_io_start_write(cdata->inode,
1646 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1647 			0, task->tk_start);
1648 }
1649 
1650 static void ff_layout_commit_record_layoutstats_done(struct rpc_task *task,
1651 		struct nfs_commit_data *cdata)
1652 {
1653 	struct nfs_page *req;
1654 	__u64 count = 0;
1655 
1656 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &cdata->flags))
1657 		return;
1658 
1659 	if (task->tk_status == 0) {
1660 		list_for_each_entry(req, &cdata->pages, wb_list)
1661 			count += req->wb_bytes;
1662 	}
1663 	nfs4_ff_layout_stat_io_end_write(task,
1664 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1665 			count, count, NFS_FILE_SYNC);
1666 }
1667 
1668 static void ff_layout_commit_prepare_common(struct rpc_task *task,
1669 		struct nfs_commit_data *cdata)
1670 {
1671 	ff_layout_commit_record_layoutstats_start(task, cdata);
1672 }
1673 
1674 static void ff_layout_commit_prepare_v3(struct rpc_task *task, void *data)
1675 {
1676 	ff_layout_commit_prepare_common(task, data);
1677 	rpc_call_start(task);
1678 }
1679 
1680 static void ff_layout_commit_prepare_v4(struct rpc_task *task, void *data)
1681 {
1682 	struct nfs_commit_data *wdata = data;
1683 
1684 	if (ff_layout_setup_sequence(wdata->ds_clp,
1685 				 &wdata->args.seq_args,
1686 				 &wdata->res.seq_res,
1687 				 task))
1688 		return;
1689 	ff_layout_commit_prepare_common(task, data);
1690 }
1691 
1692 static void ff_layout_commit_done(struct rpc_task *task, void *data)
1693 {
1694 	pnfs_generic_write_commit_done(task, data);
1695 }
1696 
1697 static void ff_layout_commit_count_stats(struct rpc_task *task, void *data)
1698 {
1699 	struct nfs_commit_data *cdata = data;
1700 
1701 	ff_layout_commit_record_layoutstats_done(task, cdata);
1702 	rpc_count_iostats_metrics(task,
1703 	    &NFS_CLIENT(cdata->inode)->cl_metrics[NFSPROC4_CLNT_COMMIT]);
1704 }
1705 
1706 static void ff_layout_commit_release(void *data)
1707 {
1708 	struct nfs_commit_data *cdata = data;
1709 
1710 	ff_layout_commit_record_layoutstats_done(&cdata->task, cdata);
1711 	pnfs_generic_commit_release(data);
1712 }
1713 
1714 static const struct rpc_call_ops ff_layout_read_call_ops_v3 = {
1715 	.rpc_call_prepare = ff_layout_read_prepare_v3,
1716 	.rpc_call_done = ff_layout_read_call_done,
1717 	.rpc_count_stats = ff_layout_read_count_stats,
1718 	.rpc_release = ff_layout_read_release,
1719 };
1720 
1721 static const struct rpc_call_ops ff_layout_read_call_ops_v4 = {
1722 	.rpc_call_prepare = ff_layout_read_prepare_v4,
1723 	.rpc_call_done = ff_layout_read_call_done,
1724 	.rpc_count_stats = ff_layout_read_count_stats,
1725 	.rpc_release = ff_layout_read_release,
1726 };
1727 
1728 static const struct rpc_call_ops ff_layout_write_call_ops_v3 = {
1729 	.rpc_call_prepare = ff_layout_write_prepare_v3,
1730 	.rpc_call_done = ff_layout_write_call_done,
1731 	.rpc_count_stats = ff_layout_write_count_stats,
1732 	.rpc_release = ff_layout_write_release,
1733 };
1734 
1735 static const struct rpc_call_ops ff_layout_write_call_ops_v4 = {
1736 	.rpc_call_prepare = ff_layout_write_prepare_v4,
1737 	.rpc_call_done = ff_layout_write_call_done,
1738 	.rpc_count_stats = ff_layout_write_count_stats,
1739 	.rpc_release = ff_layout_write_release,
1740 };
1741 
1742 static const struct rpc_call_ops ff_layout_commit_call_ops_v3 = {
1743 	.rpc_call_prepare = ff_layout_commit_prepare_v3,
1744 	.rpc_call_done = ff_layout_commit_done,
1745 	.rpc_count_stats = ff_layout_commit_count_stats,
1746 	.rpc_release = ff_layout_commit_release,
1747 };
1748 
1749 static const struct rpc_call_ops ff_layout_commit_call_ops_v4 = {
1750 	.rpc_call_prepare = ff_layout_commit_prepare_v4,
1751 	.rpc_call_done = ff_layout_commit_done,
1752 	.rpc_count_stats = ff_layout_commit_count_stats,
1753 	.rpc_release = ff_layout_commit_release,
1754 };
1755 
1756 static enum pnfs_try_status
1757 ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
1758 {
1759 	struct pnfs_layout_segment *lseg = hdr->lseg;
1760 	struct nfs4_pnfs_ds *ds;
1761 	struct rpc_clnt *ds_clnt;
1762 	struct rpc_cred *ds_cred;
1763 	loff_t offset = hdr->args.offset;
1764 	u32 idx = hdr->pgio_mirror_idx;
1765 	int vers;
1766 	struct nfs_fh *fh;
1767 
1768 	dprintk("--> %s ino %lu pgbase %u req %Zu@%llu\n",
1769 		__func__, hdr->inode->i_ino,
1770 		hdr->args.pgbase, (size_t)hdr->args.count, offset);
1771 
1772 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, false);
1773 	if (!ds)
1774 		goto out_failed;
1775 
1776 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1777 						   hdr->inode);
1778 	if (IS_ERR(ds_clnt))
1779 		goto out_failed;
1780 
1781 	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
1782 	if (!ds_cred)
1783 		goto out_failed;
1784 
1785 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1786 
1787 	dprintk("%s USE DS: %s cl_count %d vers %d\n", __func__,
1788 		ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count), vers);
1789 
1790 	hdr->pgio_done_cb = ff_layout_read_done_cb;
1791 	atomic_inc(&ds->ds_clp->cl_count);
1792 	hdr->ds_clp = ds->ds_clp;
1793 	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
1794 	if (fh)
1795 		hdr->args.fh = fh;
1796 	/*
1797 	 * Note that if we ever decide to split across DSes,
1798 	 * then we may need to handle dense-like offsets.
1799 	 */
1800 	hdr->args.offset = offset;
1801 	hdr->mds_offset = offset;
1802 
1803 	/* Perform an asynchronous read to ds */
1804 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1805 			  vers == 3 ? &ff_layout_read_call_ops_v3 :
1806 				      &ff_layout_read_call_ops_v4,
1807 			  0, RPC_TASK_SOFTCONN);
1808 	put_rpccred(ds_cred);
1809 	return PNFS_ATTEMPTED;
1810 
1811 out_failed:
1812 	if (ff_layout_avoid_mds_available_ds(lseg))
1813 		return PNFS_TRY_AGAIN;
1814 	return PNFS_NOT_ATTEMPTED;
1815 }
1816 
1817 /* Perform async writes. */
1818 static enum pnfs_try_status
1819 ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
1820 {
1821 	struct pnfs_layout_segment *lseg = hdr->lseg;
1822 	struct nfs4_pnfs_ds *ds;
1823 	struct rpc_clnt *ds_clnt;
1824 	struct rpc_cred *ds_cred;
1825 	loff_t offset = hdr->args.offset;
1826 	int vers;
1827 	struct nfs_fh *fh;
1828 	int idx = hdr->pgio_mirror_idx;
1829 
1830 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
1831 	if (!ds)
1832 		return PNFS_NOT_ATTEMPTED;
1833 
1834 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1835 						   hdr->inode);
1836 	if (IS_ERR(ds_clnt))
1837 		return PNFS_NOT_ATTEMPTED;
1838 
1839 	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
1840 	if (!ds_cred)
1841 		return PNFS_NOT_ATTEMPTED;
1842 
1843 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1844 
1845 	dprintk("%s ino %lu sync %d req %Zu@%llu DS: %s cl_count %d vers %d\n",
1846 		__func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
1847 		offset, ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count),
1848 		vers);
1849 
1850 	hdr->pgio_done_cb = ff_layout_write_done_cb;
1851 	atomic_inc(&ds->ds_clp->cl_count);
1852 	hdr->ds_clp = ds->ds_clp;
1853 	hdr->ds_commit_idx = idx;
1854 	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
1855 	if (fh)
1856 		hdr->args.fh = fh;
1857 
1858 	/*
1859 	 * Note that if we ever decide to split across DSes,
1860 	 * then we may need to handle dense-like offsets.
1861 	 */
1862 	hdr->args.offset = offset;
1863 
1864 	/* Perform an asynchronous write */
1865 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1866 			  vers == 3 ? &ff_layout_write_call_ops_v3 :
1867 				      &ff_layout_write_call_ops_v4,
1868 			  sync, RPC_TASK_SOFTCONN);
1869 	put_rpccred(ds_cred);
1870 	return PNFS_ATTEMPTED;
1871 }
1872 
1873 static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1874 {
1875 	return i;
1876 }
1877 
1878 static struct nfs_fh *
1879 select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1880 {
1881 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
1882 
1883 	/* FIXME: Assume that there is only one NFS version available
1884 	 * for the DS.
1885 	 */
1886 	return &flseg->mirror_array[i]->fh_versions[0];
1887 }
1888 
1889 static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
1890 {
1891 	struct pnfs_layout_segment *lseg = data->lseg;
1892 	struct nfs4_pnfs_ds *ds;
1893 	struct rpc_clnt *ds_clnt;
1894 	struct rpc_cred *ds_cred;
1895 	u32 idx;
1896 	int vers, ret;
1897 	struct nfs_fh *fh;
1898 
1899 	idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
1900 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
1901 	if (!ds)
1902 		goto out_err;
1903 
1904 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1905 						   data->inode);
1906 	if (IS_ERR(ds_clnt))
1907 		goto out_err;
1908 
1909 	ds_cred = ff_layout_get_ds_cred(lseg, idx, data->cred);
1910 	if (!ds_cred)
1911 		goto out_err;
1912 
1913 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1914 
1915 	dprintk("%s ino %lu, how %d cl_count %d vers %d\n", __func__,
1916 		data->inode->i_ino, how, atomic_read(&ds->ds_clp->cl_count),
1917 		vers);
1918 	data->commit_done_cb = ff_layout_commit_done_cb;
1919 	data->cred = ds_cred;
1920 	atomic_inc(&ds->ds_clp->cl_count);
1921 	data->ds_clp = ds->ds_clp;
1922 	fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
1923 	if (fh)
1924 		data->args.fh = fh;
1925 
1926 	ret = nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
1927 				   vers == 3 ? &ff_layout_commit_call_ops_v3 :
1928 					       &ff_layout_commit_call_ops_v4,
1929 				   how, RPC_TASK_SOFTCONN);
1930 	put_rpccred(ds_cred);
1931 	return ret;
1932 out_err:
1933 	pnfs_generic_prepare_to_resend_writes(data);
1934 	pnfs_generic_commit_release(data);
1935 	return -EAGAIN;
1936 }
1937 
1938 static int
1939 ff_layout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
1940 			   int how, struct nfs_commit_info *cinfo)
1941 {
1942 	return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
1943 					    ff_layout_initiate_commit);
1944 }
1945 
1946 static struct pnfs_ds_commit_info *
1947 ff_layout_get_ds_info(struct inode *inode)
1948 {
1949 	struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
1950 
1951 	if (layout == NULL)
1952 		return NULL;
1953 
1954 	return &FF_LAYOUT_FROM_HDR(layout)->commit_info;
1955 }
1956 
1957 static void
1958 ff_layout_free_deviceid_node(struct nfs4_deviceid_node *d)
1959 {
1960 	nfs4_ff_layout_free_deviceid(container_of(d, struct nfs4_ff_layout_ds,
1961 						  id_node));
1962 }
1963 
1964 static int ff_layout_encode_ioerr(struct nfs4_flexfile_layout *flo,
1965 				  struct xdr_stream *xdr,
1966 				  const struct nfs4_layoutreturn_args *args)
1967 {
1968 	struct pnfs_layout_hdr *hdr = &flo->generic_hdr;
1969 	__be32 *start;
1970 	int count = 0, ret = 0;
1971 
1972 	start = xdr_reserve_space(xdr, 4);
1973 	if (unlikely(!start))
1974 		return -E2BIG;
1975 
1976 	/* This assume we always return _ALL_ layouts */
1977 	spin_lock(&hdr->plh_inode->i_lock);
1978 	ret = ff_layout_encode_ds_ioerr(flo, xdr, &count, &args->range);
1979 	spin_unlock(&hdr->plh_inode->i_lock);
1980 
1981 	*start = cpu_to_be32(count);
1982 
1983 	return ret;
1984 }
1985 
1986 /* report nothing for now */
1987 static void ff_layout_encode_iostats(struct nfs4_flexfile_layout *flo,
1988 				     struct xdr_stream *xdr,
1989 				     const struct nfs4_layoutreturn_args *args)
1990 {
1991 	__be32 *p;
1992 
1993 	p = xdr_reserve_space(xdr, 4);
1994 	if (likely(p))
1995 		*p = cpu_to_be32(0);
1996 }
1997 
1998 static struct nfs4_deviceid_node *
1999 ff_layout_alloc_deviceid_node(struct nfs_server *server,
2000 			      struct pnfs_device *pdev, gfp_t gfp_flags)
2001 {
2002 	struct nfs4_ff_layout_ds *dsaddr;
2003 
2004 	dsaddr = nfs4_ff_alloc_deviceid_node(server, pdev, gfp_flags);
2005 	if (!dsaddr)
2006 		return NULL;
2007 	return &dsaddr->id_node;
2008 }
2009 
2010 static void
2011 ff_layout_encode_layoutreturn(struct pnfs_layout_hdr *lo,
2012 			      struct xdr_stream *xdr,
2013 			      const struct nfs4_layoutreturn_args *args)
2014 {
2015 	struct nfs4_flexfile_layout *flo = FF_LAYOUT_FROM_HDR(lo);
2016 	__be32 *start;
2017 
2018 	dprintk("%s: Begin\n", __func__);
2019 	start = xdr_reserve_space(xdr, 4);
2020 	BUG_ON(!start);
2021 
2022 	ff_layout_encode_ioerr(flo, xdr, args);
2023 	ff_layout_encode_iostats(flo, xdr, args);
2024 
2025 	*start = cpu_to_be32((xdr->p - start - 1) * 4);
2026 	dprintk("%s: Return\n", __func__);
2027 }
2028 
2029 static int
2030 ff_layout_ntop4(const struct sockaddr *sap, char *buf, const size_t buflen)
2031 {
2032 	const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
2033 
2034 	return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
2035 }
2036 
2037 static size_t
2038 ff_layout_ntop6_noscopeid(const struct sockaddr *sap, char *buf,
2039 			  const int buflen)
2040 {
2041 	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
2042 	const struct in6_addr *addr = &sin6->sin6_addr;
2043 
2044 	/*
2045 	 * RFC 4291, Section 2.2.2
2046 	 *
2047 	 * Shorthanded ANY address
2048 	 */
2049 	if (ipv6_addr_any(addr))
2050 		return snprintf(buf, buflen, "::");
2051 
2052 	/*
2053 	 * RFC 4291, Section 2.2.2
2054 	 *
2055 	 * Shorthanded loopback address
2056 	 */
2057 	if (ipv6_addr_loopback(addr))
2058 		return snprintf(buf, buflen, "::1");
2059 
2060 	/*
2061 	 * RFC 4291, Section 2.2.3
2062 	 *
2063 	 * Special presentation address format for mapped v4
2064 	 * addresses.
2065 	 */
2066 	if (ipv6_addr_v4mapped(addr))
2067 		return snprintf(buf, buflen, "::ffff:%pI4",
2068 					&addr->s6_addr32[3]);
2069 
2070 	/*
2071 	 * RFC 4291, Section 2.2.1
2072 	 */
2073 	return snprintf(buf, buflen, "%pI6c", addr);
2074 }
2075 
2076 /* Derived from rpc_sockaddr2uaddr */
2077 static void
2078 ff_layout_encode_netaddr(struct xdr_stream *xdr, struct nfs4_pnfs_ds_addr *da)
2079 {
2080 	struct sockaddr *sap = (struct sockaddr *)&da->da_addr;
2081 	char portbuf[RPCBIND_MAXUADDRPLEN];
2082 	char addrbuf[RPCBIND_MAXUADDRLEN];
2083 	char *netid;
2084 	unsigned short port;
2085 	int len, netid_len;
2086 	__be32 *p;
2087 
2088 	switch (sap->sa_family) {
2089 	case AF_INET:
2090 		if (ff_layout_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
2091 			return;
2092 		port = ntohs(((struct sockaddr_in *)sap)->sin_port);
2093 		netid = "tcp";
2094 		netid_len = 3;
2095 		break;
2096 	case AF_INET6:
2097 		if (ff_layout_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
2098 			return;
2099 		port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
2100 		netid = "tcp6";
2101 		netid_len = 4;
2102 		break;
2103 	default:
2104 		/* we only support tcp and tcp6 */
2105 		WARN_ON_ONCE(1);
2106 		return;
2107 	}
2108 
2109 	snprintf(portbuf, sizeof(portbuf), ".%u.%u", port >> 8, port & 0xff);
2110 	len = strlcat(addrbuf, portbuf, sizeof(addrbuf));
2111 
2112 	p = xdr_reserve_space(xdr, 4 + netid_len);
2113 	xdr_encode_opaque(p, netid, netid_len);
2114 
2115 	p = xdr_reserve_space(xdr, 4 + len);
2116 	xdr_encode_opaque(p, addrbuf, len);
2117 }
2118 
2119 static void
2120 ff_layout_encode_nfstime(struct xdr_stream *xdr,
2121 			 ktime_t t)
2122 {
2123 	struct timespec64 ts;
2124 	__be32 *p;
2125 
2126 	p = xdr_reserve_space(xdr, 12);
2127 	ts = ktime_to_timespec64(t);
2128 	p = xdr_encode_hyper(p, ts.tv_sec);
2129 	*p++ = cpu_to_be32(ts.tv_nsec);
2130 }
2131 
2132 static void
2133 ff_layout_encode_io_latency(struct xdr_stream *xdr,
2134 			    struct nfs4_ff_io_stat *stat)
2135 {
2136 	__be32 *p;
2137 
2138 	p = xdr_reserve_space(xdr, 5 * 8);
2139 	p = xdr_encode_hyper(p, stat->ops_requested);
2140 	p = xdr_encode_hyper(p, stat->bytes_requested);
2141 	p = xdr_encode_hyper(p, stat->ops_completed);
2142 	p = xdr_encode_hyper(p, stat->bytes_completed);
2143 	p = xdr_encode_hyper(p, stat->bytes_not_delivered);
2144 	ff_layout_encode_nfstime(xdr, stat->total_busy_time);
2145 	ff_layout_encode_nfstime(xdr, stat->aggregate_completion_time);
2146 }
2147 
2148 static void
2149 ff_layout_encode_layoutstats(struct xdr_stream *xdr,
2150 			     struct nfs42_layoutstat_args *args,
2151 			     struct nfs42_layoutstat_devinfo *devinfo)
2152 {
2153 	struct nfs4_ff_layout_mirror *mirror = devinfo->layout_private;
2154 	struct nfs4_pnfs_ds_addr *da;
2155 	struct nfs4_pnfs_ds *ds = mirror->mirror_ds->ds;
2156 	struct nfs_fh *fh = &mirror->fh_versions[0];
2157 	__be32 *p, *start;
2158 
2159 	da = list_first_entry(&ds->ds_addrs, struct nfs4_pnfs_ds_addr, da_node);
2160 	dprintk("%s: DS %s: encoding address %s\n",
2161 		__func__, ds->ds_remotestr, da->da_remotestr);
2162 	/* layoutupdate length */
2163 	start = xdr_reserve_space(xdr, 4);
2164 	/* netaddr4 */
2165 	ff_layout_encode_netaddr(xdr, da);
2166 	/* nfs_fh4 */
2167 	p = xdr_reserve_space(xdr, 4 + fh->size);
2168 	xdr_encode_opaque(p, fh->data, fh->size);
2169 	/* ff_io_latency4 read */
2170 	spin_lock(&mirror->lock);
2171 	ff_layout_encode_io_latency(xdr, &mirror->read_stat.io_stat);
2172 	/* ff_io_latency4 write */
2173 	ff_layout_encode_io_latency(xdr, &mirror->write_stat.io_stat);
2174 	spin_unlock(&mirror->lock);
2175 	/* nfstime4 */
2176 	ff_layout_encode_nfstime(xdr, ktime_sub(ktime_get(), mirror->start_time));
2177 	/* bool */
2178 	p = xdr_reserve_space(xdr, 4);
2179 	*p = cpu_to_be32(false);
2180 
2181 	*start = cpu_to_be32((xdr->p - start - 1) * 4);
2182 }
2183 
2184 static int
2185 ff_layout_mirror_prepare_stats(struct nfs42_layoutstat_args *args,
2186 			       struct pnfs_layout_hdr *lo,
2187 			       int dev_limit)
2188 {
2189 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
2190 	struct nfs4_ff_layout_mirror *mirror;
2191 	struct nfs4_deviceid_node *dev;
2192 	struct nfs42_layoutstat_devinfo *devinfo;
2193 	int i = 0;
2194 
2195 	list_for_each_entry(mirror, &ff_layout->mirrors, mirrors) {
2196 		if (i >= dev_limit)
2197 			break;
2198 		if (!mirror->mirror_ds)
2199 			continue;
2200 		/* mirror refcount put in cleanup_layoutstats */
2201 		if (!atomic_inc_not_zero(&mirror->ref))
2202 			continue;
2203 		dev = &mirror->mirror_ds->id_node;
2204 		devinfo = &args->devinfo[i];
2205 		memcpy(&devinfo->dev_id, &dev->deviceid, NFS4_DEVICEID4_SIZE);
2206 		devinfo->offset = 0;
2207 		devinfo->length = NFS4_MAX_UINT64;
2208 		devinfo->read_count = mirror->read_stat.io_stat.ops_completed;
2209 		devinfo->read_bytes = mirror->read_stat.io_stat.bytes_completed;
2210 		devinfo->write_count = mirror->write_stat.io_stat.ops_completed;
2211 		devinfo->write_bytes = mirror->write_stat.io_stat.bytes_completed;
2212 		devinfo->layout_type = LAYOUT_FLEX_FILES;
2213 		devinfo->layoutstats_encode = ff_layout_encode_layoutstats;
2214 		devinfo->layout_private = mirror;
2215 
2216 		i++;
2217 	}
2218 	return i;
2219 }
2220 
2221 static int
2222 ff_layout_prepare_layoutstats(struct nfs42_layoutstat_args *args)
2223 {
2224 	struct nfs4_flexfile_layout *ff_layout;
2225 	struct nfs4_ff_layout_mirror *mirror;
2226 	int dev_count = 0;
2227 
2228 	spin_lock(&args->inode->i_lock);
2229 	ff_layout = FF_LAYOUT_FROM_HDR(NFS_I(args->inode)->layout);
2230 	list_for_each_entry(mirror, &ff_layout->mirrors, mirrors) {
2231 		if (atomic_read(&mirror->ref) != 0)
2232 			dev_count ++;
2233 	}
2234 	spin_unlock(&args->inode->i_lock);
2235 	/* For now, send at most PNFS_LAYOUTSTATS_MAXDEV statistics */
2236 	if (dev_count > PNFS_LAYOUTSTATS_MAXDEV) {
2237 		dprintk("%s: truncating devinfo to limit (%d:%d)\n",
2238 			__func__, dev_count, PNFS_LAYOUTSTATS_MAXDEV);
2239 		dev_count = PNFS_LAYOUTSTATS_MAXDEV;
2240 	}
2241 	args->devinfo = kmalloc_array(dev_count, sizeof(*args->devinfo), GFP_NOIO);
2242 	if (!args->devinfo)
2243 		return -ENOMEM;
2244 
2245 	spin_lock(&args->inode->i_lock);
2246 	args->num_dev = ff_layout_mirror_prepare_stats(args,
2247 			&ff_layout->generic_hdr, dev_count);
2248 	spin_unlock(&args->inode->i_lock);
2249 
2250 	return 0;
2251 }
2252 
2253 static void
2254 ff_layout_cleanup_layoutstats(struct nfs42_layoutstat_data *data)
2255 {
2256 	struct nfs4_ff_layout_mirror *mirror;
2257 	int i;
2258 
2259 	for (i = 0; i < data->args.num_dev; i++) {
2260 		mirror = data->args.devinfo[i].layout_private;
2261 		data->args.devinfo[i].layout_private = NULL;
2262 		ff_layout_put_mirror(mirror);
2263 	}
2264 }
2265 
2266 static struct pnfs_layoutdriver_type flexfilelayout_type = {
2267 	.id			= LAYOUT_FLEX_FILES,
2268 	.name			= "LAYOUT_FLEX_FILES",
2269 	.owner			= THIS_MODULE,
2270 	.alloc_layout_hdr	= ff_layout_alloc_layout_hdr,
2271 	.free_layout_hdr	= ff_layout_free_layout_hdr,
2272 	.alloc_lseg		= ff_layout_alloc_lseg,
2273 	.free_lseg		= ff_layout_free_lseg,
2274 	.add_lseg		= ff_layout_add_lseg,
2275 	.pg_read_ops		= &ff_layout_pg_read_ops,
2276 	.pg_write_ops		= &ff_layout_pg_write_ops,
2277 	.get_ds_info		= ff_layout_get_ds_info,
2278 	.free_deviceid_node	= ff_layout_free_deviceid_node,
2279 	.mark_request_commit	= pnfs_layout_mark_request_commit,
2280 	.clear_request_commit	= pnfs_generic_clear_request_commit,
2281 	.scan_commit_lists	= pnfs_generic_scan_commit_lists,
2282 	.recover_commit_reqs	= pnfs_generic_recover_commit_reqs,
2283 	.commit_pagelist	= ff_layout_commit_pagelist,
2284 	.read_pagelist		= ff_layout_read_pagelist,
2285 	.write_pagelist		= ff_layout_write_pagelist,
2286 	.alloc_deviceid_node    = ff_layout_alloc_deviceid_node,
2287 	.encode_layoutreturn    = ff_layout_encode_layoutreturn,
2288 	.sync			= pnfs_nfs_generic_sync,
2289 	.prepare_layoutstats	= ff_layout_prepare_layoutstats,
2290 	.cleanup_layoutstats	= ff_layout_cleanup_layoutstats,
2291 };
2292 
2293 static int __init nfs4flexfilelayout_init(void)
2294 {
2295 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Registering...\n",
2296 	       __func__);
2297 	if (!ff_zero_group) {
2298 		ff_zero_group = groups_alloc(0);
2299 		if (!ff_zero_group)
2300 			return -ENOMEM;
2301 	}
2302 	return pnfs_register_layoutdriver(&flexfilelayout_type);
2303 }
2304 
2305 static void __exit nfs4flexfilelayout_exit(void)
2306 {
2307 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Unregistering...\n",
2308 	       __func__);
2309 	pnfs_unregister_layoutdriver(&flexfilelayout_type);
2310 	if (ff_zero_group) {
2311 		put_group_info(ff_zero_group);
2312 		ff_zero_group = NULL;
2313 	}
2314 }
2315 
2316 MODULE_ALIAS("nfs-layouttype4-4");
2317 
2318 MODULE_LICENSE("GPL");
2319 MODULE_DESCRIPTION("The NFSv4 flexfile layout driver");
2320 
2321 module_init(nfs4flexfilelayout_init);
2322 module_exit(nfs4flexfilelayout_exit);
2323