xref: /linux/fs/nfs/flexfilelayout/flexfilelayout.c (revision 995832b2cebe6969d1b42635db698803ee31294d)
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/file.h>
15 #include <linux/sched/mm.h>
16 
17 #include <linux/sunrpc/metrics.h>
18 
19 #include "flexfilelayout.h"
20 #include "../nfs4session.h"
21 #include "../nfs4idmap.h"
22 #include "../internal.h"
23 #include "../delegation.h"
24 #include "../nfs4trace.h"
25 #include "../iostat.h"
26 #include "../nfs.h"
27 #include "../nfs42.h"
28 
29 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
30 
31 #define FF_LAYOUT_POLL_RETRY_MAX     (15*HZ)
32 #define FF_LAYOUTRETURN_MAXERR 20
33 
34 enum nfs4_ff_op_type {
35 	NFS4_FF_OP_LAYOUTSTATS,
36 	NFS4_FF_OP_LAYOUTRETURN,
37 };
38 
39 static unsigned short io_maxretrans;
40 
41 static const struct pnfs_commit_ops ff_layout_commit_ops;
42 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
43 		struct nfs_pgio_header *hdr);
44 static int
45 ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
46 			       struct nfs42_layoutstat_devinfo *devinfo,
47 			       int dev_limit, enum nfs4_ff_op_type type);
48 static void ff_layout_encode_ff_layoutupdate(struct xdr_stream *xdr,
49 			      const struct nfs42_layoutstat_devinfo *devinfo,
50 			      struct nfs4_ff_layout_ds_stripe *dss_info);
51 
52 static struct pnfs_layout_hdr *
53 ff_layout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags)
54 {
55 	struct nfs4_flexfile_layout *ffl;
56 
57 	ffl = kzalloc_obj(*ffl, gfp_flags);
58 	if (ffl) {
59 		pnfs_init_ds_commit_info(&ffl->commit_info);
60 		INIT_LIST_HEAD(&ffl->error_list);
61 		INIT_LIST_HEAD(&ffl->mirrors);
62 		ffl->last_report_time = ktime_get();
63 		ffl->commit_info.ops = &ff_layout_commit_ops;
64 		return &ffl->generic_hdr;
65 	} else
66 		return NULL;
67 }
68 
69 static void
70 ff_layout_free_layout_hdr(struct pnfs_layout_hdr *lo)
71 {
72 	struct nfs4_flexfile_layout *ffl = FF_LAYOUT_FROM_HDR(lo);
73 	struct nfs4_ff_layout_ds_err *err, *n;
74 
75 	list_for_each_entry_safe(err, n, &ffl->error_list, list) {
76 		list_del(&err->list);
77 		kfree(err);
78 	}
79 	kfree_rcu(ffl, generic_hdr.plh_rcu);
80 }
81 
82 static int decode_pnfs_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
83 {
84 	__be32 *p;
85 
86 	p = xdr_inline_decode(xdr, NFS4_STATEID_SIZE);
87 	if (unlikely(p == NULL))
88 		return -ENOBUFS;
89 	stateid->type = NFS4_PNFS_DS_STATEID_TYPE;
90 	memcpy(stateid->data, p, NFS4_STATEID_SIZE);
91 	dprintk("%s: stateid id= [%x%x%x%x]\n", __func__,
92 		p[0], p[1], p[2], p[3]);
93 	return 0;
94 }
95 
96 static int decode_deviceid(struct xdr_stream *xdr, struct nfs4_deviceid *devid)
97 {
98 	__be32 *p;
99 
100 	p = xdr_inline_decode(xdr, NFS4_DEVICEID4_SIZE);
101 	if (unlikely(!p))
102 		return -ENOBUFS;
103 	memcpy(devid, p, NFS4_DEVICEID4_SIZE);
104 	nfs4_print_deviceid(devid);
105 	return 0;
106 }
107 
108 static int decode_nfs_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
109 {
110 	__be32 *p;
111 
112 	p = xdr_inline_decode(xdr, 4);
113 	if (unlikely(!p))
114 		return -ENOBUFS;
115 	fh->size = be32_to_cpup(p++);
116 	if (fh->size > NFS_MAXFHSIZE) {
117 		printk(KERN_ERR "NFS flexfiles: Too big fh received %d\n",
118 		       fh->size);
119 		return -EOVERFLOW;
120 	}
121 	/* fh.data */
122 	p = xdr_inline_decode(xdr, fh->size);
123 	if (unlikely(!p))
124 		return -ENOBUFS;
125 	memcpy(&fh->data, p, fh->size);
126 	dprintk("%s: fh len %d\n", __func__, fh->size);
127 
128 	return 0;
129 }
130 
131 /*
132  * Currently only stringified uids and gids are accepted.
133  * I.e., kerberos is not supported to the DSes, so no pricipals.
134  *
135  * That means that one common function will suffice, but when
136  * principals are added, this should be split to accomodate
137  * calls to both nfs_map_name_to_uid() and nfs_map_group_to_gid().
138  */
139 static int
140 decode_name(struct xdr_stream *xdr, u32 *id)
141 {
142 	__be32 *p;
143 	int len;
144 
145 	/* opaque_length(4)*/
146 	p = xdr_inline_decode(xdr, 4);
147 	if (unlikely(!p))
148 		return -ENOBUFS;
149 	len = be32_to_cpup(p++);
150 	if (len < 0)
151 		return -EINVAL;
152 
153 	dprintk("%s: len %u\n", __func__, len);
154 
155 	/* opaque body */
156 	p = xdr_inline_decode(xdr, len);
157 	if (unlikely(!p))
158 		return -ENOBUFS;
159 
160 	if (!nfs_map_string_to_numeric((char *)p, len, id))
161 		return -EINVAL;
162 
163 	return 0;
164 }
165 
166 static struct nfsd_file *
167 ff_local_open_fh(struct pnfs_layout_segment *lseg, u32 ds_idx, u32 dss_id,
168 		 struct nfs_client *clp, const struct cred *cred,
169 		 struct nfs_fh *fh, fmode_t mode)
170 {
171 #if IS_ENABLED(CONFIG_NFS_LOCALIO)
172 	struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx);
173 
174 	return nfs_local_open_fh(clp, cred, fh, &mirror->dss[dss_id].nfl, mode);
175 #else
176 	return NULL;
177 #endif
178 }
179 
180 static bool ff_dss_match_fh(const struct nfs4_ff_layout_ds_stripe *dss1,
181 		const struct nfs4_ff_layout_ds_stripe *dss2)
182 {
183 	int i, j;
184 
185 	if (dss1->fh_versions_cnt != dss2->fh_versions_cnt)
186 		return false;
187 
188 	for (i = 0; i < dss1->fh_versions_cnt; i++) {
189 		bool found_fh = false;
190 		for (j = 0; j < dss2->fh_versions_cnt; j++) {
191 			if (nfs_compare_fh(&dss1->fh_versions[i],
192 					&dss2->fh_versions[j]) == 0) {
193 				found_fh = true;
194 				break;
195 			}
196 		}
197 		if (!found_fh)
198 			return false;
199 	}
200 	return true;
201 }
202 
203 static bool ff_mirror_match_fh(const struct nfs4_ff_layout_mirror *m1,
204 		const struct nfs4_ff_layout_mirror *m2)
205 {
206 	u32 dss_id;
207 
208 	if (m1->dss_count != m2->dss_count)
209 		return false;
210 
211 	for (dss_id = 0; dss_id < m1->dss_count; dss_id++)
212 		if (!ff_dss_match_fh(&m1->dss[dss_id], &m2->dss[dss_id]))
213 			return false;
214 
215 	return true;
216 }
217 
218 static bool ff_mirror_match_devid(const struct nfs4_ff_layout_mirror *m1,
219 		const struct nfs4_ff_layout_mirror *m2)
220 {
221 	u32 dss_id;
222 
223 	if (m1->dss_count != m2->dss_count)
224 		return false;
225 
226 	for (dss_id = 0; dss_id < m1->dss_count; dss_id++)
227 		if (memcmp(&m1->dss[dss_id].devid,
228 			   &m2->dss[dss_id].devid,
229 			   sizeof(m1->dss[dss_id].devid)) != 0)
230 			return false;
231 
232 	return true;
233 }
234 
235 static struct nfs4_ff_layout_mirror *
236 ff_layout_add_mirror(struct pnfs_layout_hdr *lo,
237 		struct nfs4_ff_layout_mirror *mirror)
238 {
239 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
240 	struct nfs4_ff_layout_mirror *pos;
241 	struct inode *inode = lo->plh_inode;
242 
243 	spin_lock(&inode->i_lock);
244 	list_for_each_entry(pos, &ff_layout->mirrors, mirrors) {
245 		if (!ff_mirror_match_devid(mirror, pos))
246 			continue;
247 		if (!ff_mirror_match_fh(mirror, pos))
248 			continue;
249 		if (refcount_inc_not_zero(&pos->ref)) {
250 			spin_unlock(&inode->i_lock);
251 			return pos;
252 		}
253 	}
254 	list_add(&mirror->mirrors, &ff_layout->mirrors);
255 	mirror->layout = lo;
256 	spin_unlock(&inode->i_lock);
257 	return mirror;
258 }
259 
260 static void
261 ff_layout_remove_mirror(struct nfs4_ff_layout_mirror *mirror)
262 {
263 	struct inode *inode;
264 	if (mirror->layout == NULL)
265 		return;
266 	inode = mirror->layout->plh_inode;
267 	spin_lock(&inode->i_lock);
268 	list_del(&mirror->mirrors);
269 	spin_unlock(&inode->i_lock);
270 	mirror->layout = NULL;
271 }
272 
273 static struct nfs4_ff_layout_mirror *ff_layout_alloc_mirror(u32 dss_count,
274 							    gfp_t gfp_flags)
275 {
276 	struct nfs4_ff_layout_mirror *mirror;
277 
278 	mirror = kzalloc_obj(*mirror, gfp_flags);
279 	if (mirror == NULL)
280 		return NULL;
281 
282 	spin_lock_init(&mirror->lock);
283 	refcount_set(&mirror->ref, 1);
284 	INIT_LIST_HEAD(&mirror->mirrors);
285 
286 	mirror->dss_count = dss_count;
287 	mirror->dss =
288 		kzalloc_objs(struct nfs4_ff_layout_ds_stripe, dss_count,
289 			     gfp_flags);
290 	if (mirror->dss == NULL) {
291 		kfree(mirror);
292 		return NULL;
293 	}
294 
295 	for (u32 dss_id = 0; dss_id < mirror->dss_count; dss_id++)
296 		nfs_localio_file_init(&mirror->dss[dss_id].nfl);
297 
298 	return mirror;
299 }
300 
301 static void ff_layout_free_mirror(struct nfs4_ff_layout_mirror *mirror)
302 {
303 	const struct cred	*cred;
304 	u32 dss_id;
305 
306 	ff_layout_remove_mirror(mirror);
307 
308 	for (dss_id = 0; dss_id < mirror->dss_count; dss_id++) {
309 		kfree(mirror->dss[dss_id].fh_versions);
310 		cred = rcu_access_pointer(mirror->dss[dss_id].ro_cred);
311 		put_cred(cred);
312 		cred = rcu_access_pointer(mirror->dss[dss_id].rw_cred);
313 		put_cred(cred);
314 		nfs_close_local_fh(&mirror->dss[dss_id].nfl);
315 		nfs4_ff_layout_put_deviceid(mirror->dss[dss_id].mirror_ds);
316 	}
317 
318 	kfree(mirror->dss);
319 	kfree(mirror);
320 }
321 
322 static void ff_layout_put_mirror(struct nfs4_ff_layout_mirror *mirror)
323 {
324 	if (mirror != NULL && refcount_dec_and_test(&mirror->ref))
325 		ff_layout_free_mirror(mirror);
326 }
327 
328 static void ff_layout_free_mirror_array(struct nfs4_ff_layout_segment *fls)
329 {
330 	u32 i;
331 
332 	for (i = 0; i < fls->mirror_array_cnt; i++)
333 		ff_layout_put_mirror(fls->mirror_array[i]);
334 }
335 
336 static void _ff_layout_free_lseg(struct nfs4_ff_layout_segment *fls)
337 {
338 	if (fls) {
339 		ff_layout_free_mirror_array(fls);
340 		kfree(fls);
341 	}
342 }
343 
344 static bool
345 ff_lseg_match_mirrors(struct pnfs_layout_segment *l1,
346 		struct pnfs_layout_segment *l2)
347 {
348 	const struct nfs4_ff_layout_segment *fl1 = FF_LAYOUT_LSEG(l1);
349 	const struct nfs4_ff_layout_segment *fl2 = FF_LAYOUT_LSEG(l2);
350 	u32 i;
351 
352 	if (fl1->mirror_array_cnt != fl2->mirror_array_cnt)
353 		return false;
354 	for (i = 0; i < fl1->mirror_array_cnt; i++) {
355 		if (fl1->mirror_array[i] != fl2->mirror_array[i])
356 			return false;
357 	}
358 	return true;
359 }
360 
361 static bool
362 ff_lseg_range_is_after(const struct pnfs_layout_range *l1,
363 		const struct pnfs_layout_range *l2)
364 {
365 	u64 end1, end2;
366 
367 	if (l1->iomode != l2->iomode)
368 		return l1->iomode != IOMODE_READ;
369 	end1 = pnfs_calc_offset_end(l1->offset, l1->length);
370 	end2 = pnfs_calc_offset_end(l2->offset, l2->length);
371 	if (end1 < l2->offset)
372 		return false;
373 	if (end2 < l1->offset)
374 		return true;
375 	return l2->offset <= l1->offset;
376 }
377 
378 static bool
379 ff_lseg_merge(struct pnfs_layout_segment *new,
380 		struct pnfs_layout_segment *old)
381 {
382 	u64 new_end, old_end;
383 
384 	if (test_bit(NFS_LSEG_LAYOUTRETURN, &old->pls_flags))
385 		return false;
386 	if (new->pls_range.iomode != old->pls_range.iomode)
387 		return false;
388 	old_end = pnfs_calc_offset_end(old->pls_range.offset,
389 			old->pls_range.length);
390 	if (old_end < new->pls_range.offset)
391 		return false;
392 	new_end = pnfs_calc_offset_end(new->pls_range.offset,
393 			new->pls_range.length);
394 	if (new_end < old->pls_range.offset)
395 		return false;
396 	if (!ff_lseg_match_mirrors(new, old))
397 		return false;
398 
399 	/* Mergeable: copy info from 'old' to 'new' */
400 	if (new_end < old_end)
401 		new_end = old_end;
402 	if (new->pls_range.offset < old->pls_range.offset)
403 		new->pls_range.offset = old->pls_range.offset;
404 	new->pls_range.length = pnfs_calc_offset_length(new->pls_range.offset,
405 			new_end);
406 	if (test_bit(NFS_LSEG_ROC, &old->pls_flags))
407 		set_bit(NFS_LSEG_ROC, &new->pls_flags);
408 	return true;
409 }
410 
411 static void
412 ff_layout_add_lseg(struct pnfs_layout_hdr *lo,
413 		struct pnfs_layout_segment *lseg,
414 		struct list_head *free_me)
415 {
416 	pnfs_generic_layout_insert_lseg(lo, lseg,
417 			ff_lseg_range_is_after,
418 			ff_lseg_merge,
419 			free_me);
420 }
421 
422 static u32 ff_mirror_efficiency_sum(const struct nfs4_ff_layout_mirror *mirror)
423 {
424 	u32 dss_id, sum = 0;
425 
426 	for (dss_id = 0; dss_id < mirror->dss_count; dss_id++)
427 		sum += mirror->dss[dss_id].efficiency;
428 
429 	return sum;
430 }
431 
432 static void ff_layout_sort_mirrors(struct nfs4_ff_layout_segment *fls)
433 {
434 	int i, j;
435 
436 	for (i = 0; i < fls->mirror_array_cnt - 1; i++) {
437 		for (j = i + 1; j < fls->mirror_array_cnt; j++)
438 			if (ff_mirror_efficiency_sum(fls->mirror_array[i]) <
439 			    ff_mirror_efficiency_sum(fls->mirror_array[j]))
440 				swap(fls->mirror_array[i],
441 				     fls->mirror_array[j]);
442 	}
443 }
444 
445 static struct pnfs_layout_segment *
446 ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh,
447 		     struct nfs4_layoutget_res *lgr,
448 		     gfp_t gfp_flags)
449 {
450 	struct pnfs_layout_segment *ret;
451 	struct nfs4_ff_layout_segment *fls = NULL;
452 	struct xdr_stream stream;
453 	struct xdr_buf buf;
454 	struct folio *scratch;
455 	u64 stripe_unit;
456 	u32 mirror_array_cnt;
457 	__be32 *p;
458 	int i, rc;
459 	struct nfs4_ff_layout_ds_stripe *dss_info;
460 
461 	dprintk("--> %s\n", __func__);
462 	scratch = folio_alloc(gfp_flags, 0);
463 	if (!scratch)
464 		return ERR_PTR(-ENOMEM);
465 
466 	xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages,
467 			      lgr->layoutp->len);
468 	xdr_set_scratch_folio(&stream, scratch);
469 
470 	/* stripe unit and mirror_array_cnt */
471 	rc = -EIO;
472 	p = xdr_inline_decode(&stream, 8 + 4);
473 	if (!p)
474 		goto out_err_free;
475 
476 	p = xdr_decode_hyper(p, &stripe_unit);
477 	mirror_array_cnt = be32_to_cpup(p++);
478 	dprintk("%s: stripe_unit=%llu mirror_array_cnt=%u\n", __func__,
479 		stripe_unit, mirror_array_cnt);
480 
481 	if (mirror_array_cnt > NFS4_FLEXFILE_LAYOUT_MAX_MIRROR_CNT ||
482 	    mirror_array_cnt == 0)
483 		goto out_err_free;
484 
485 	rc = -ENOMEM;
486 	fls = kzalloc_flex(*fls, mirror_array, mirror_array_cnt, gfp_flags);
487 	if (!fls)
488 		goto out_err_free;
489 
490 	fls->mirror_array_cnt = mirror_array_cnt;
491 	fls->stripe_unit = stripe_unit;
492 
493 	u32 dss_count = 0;
494 	for (i = 0; i < fls->mirror_array_cnt; i++) {
495 		struct nfs4_ff_layout_mirror *mirror;
496 		struct cred *kcred;
497 		const struct cred __rcu *cred;
498 		kuid_t uid;
499 		kgid_t gid;
500 		u32 fh_count, id;
501 		int j, dss_id;
502 
503 		rc = -EIO;
504 		p = xdr_inline_decode(&stream, 4);
505 		if (!p)
506 			goto out_err_free;
507 
508 		// Ensure all mirrors have same stripe count.
509 		if (dss_count == 0)
510 			dss_count = be32_to_cpup(p);
511 		else if (dss_count != be32_to_cpup(p))
512 			goto out_err_free;
513 
514 		if (dss_count > NFS4_FLEXFILE_LAYOUT_MAX_STRIPE_CNT ||
515 		    dss_count == 0)
516 			goto out_err_free;
517 
518 		if (dss_count > 1 && stripe_unit == 0)
519 			goto out_err_free;
520 
521 		fls->mirror_array[i] = ff_layout_alloc_mirror(dss_count, gfp_flags);
522 		if (fls->mirror_array[i] == NULL) {
523 			rc = -ENOMEM;
524 			goto out_err_free;
525 		}
526 
527 		for (dss_id = 0; dss_id < dss_count; dss_id++) {
528 			dss_info = &fls->mirror_array[i]->dss[dss_id];
529 			dss_info->mirror = fls->mirror_array[i];
530 
531 			/* deviceid */
532 			rc = decode_deviceid(&stream, &dss_info->devid);
533 			if (rc)
534 				goto out_err_free;
535 
536 			/* efficiency */
537 			rc = -EIO;
538 			p = xdr_inline_decode(&stream, 4);
539 			if (!p)
540 				goto out_err_free;
541 			dss_info->efficiency = be32_to_cpup(p);
542 
543 			/* stateid */
544 			rc = decode_pnfs_stateid(&stream, &dss_info->stateid);
545 			if (rc)
546 				goto out_err_free;
547 
548 			/* fh */
549 			rc = -EIO;
550 			p = xdr_inline_decode(&stream, 4);
551 			if (!p)
552 				goto out_err_free;
553 			fh_count = be32_to_cpup(p);
554 			if (fh_count == 0) {
555 				rc = -EINVAL;
556 				goto out_err_free;
557 			}
558 
559 			dss_info->fh_versions =
560 			    kzalloc_objs(struct nfs_fh, fh_count, gfp_flags);
561 			if (dss_info->fh_versions == NULL) {
562 				rc = -ENOMEM;
563 				goto out_err_free;
564 			}
565 
566 			for (j = 0; j < fh_count; j++) {
567 				rc = decode_nfs_fh(&stream,
568 						   &dss_info->fh_versions[j]);
569 				if (rc)
570 					goto out_err_free;
571 			}
572 
573 			dss_info->fh_versions_cnt = fh_count;
574 
575 			/* user */
576 			rc = decode_name(&stream, &id);
577 			if (rc)
578 				goto out_err_free;
579 
580 			uid = make_kuid(&init_user_ns, id);
581 
582 			/* group */
583 			rc = decode_name(&stream, &id);
584 			if (rc)
585 				goto out_err_free;
586 
587 			gid = make_kgid(&init_user_ns, id);
588 
589 			if (gfp_flags & __GFP_FS)
590 				kcred = prepare_kernel_cred(&init_task);
591 			else {
592 				unsigned int nofs_flags = memalloc_nofs_save();
593 
594 				kcred = prepare_kernel_cred(&init_task);
595 				memalloc_nofs_restore(nofs_flags);
596 			}
597 			rc = -ENOMEM;
598 			if (!kcred)
599 				goto out_err_free;
600 			kcred->fsuid = uid;
601 			kcred->fsgid = gid;
602 			cred = RCU_INITIALIZER(kcred);
603 
604 			if (lgr->range.iomode == IOMODE_READ)
605 				rcu_assign_pointer(dss_info->ro_cred, cred);
606 			else
607 				rcu_assign_pointer(dss_info->rw_cred, cred);
608 		}
609 
610 		mirror = ff_layout_add_mirror(lh, fls->mirror_array[i]);
611 		if (mirror != fls->mirror_array[i]) {
612 			for (dss_id = 0; dss_id < dss_count; dss_id++) {
613 				dss_info = &fls->mirror_array[i]->dss[dss_id];
614 				/* swap cred ptrs so free_mirror will clean up old */
615 				if (lgr->range.iomode == IOMODE_READ) {
616 					cred = xchg(&mirror->dss[dss_id].ro_cred,
617 						    dss_info->ro_cred);
618 					rcu_assign_pointer(dss_info->ro_cred, cred);
619 				} else {
620 					cred = xchg(&mirror->dss[dss_id].rw_cred,
621 						    dss_info->rw_cred);
622 					rcu_assign_pointer(dss_info->rw_cred, cred);
623 				}
624 			}
625 			ff_layout_free_mirror(fls->mirror_array[i]);
626 			fls->mirror_array[i] = mirror;
627 		}
628 
629 		dprintk("%s: iomode %s uid %u gid %u\n", __func__,
630 			lgr->range.iomode == IOMODE_READ ? "READ" : "RW",
631 			from_kuid(&init_user_ns, uid),
632 			from_kgid(&init_user_ns, gid));
633 	}
634 
635 	p = xdr_inline_decode(&stream, 4);
636 	if (!p)
637 		goto out_sort_mirrors;
638 	fls->flags = be32_to_cpup(p);
639 	if (fls->flags & FF_FLAGS_NO_IO_THRU_MDS)
640 		set_bit(NFS4_FF_HDR_NO_IO_THRU_MDS,
641 			&FF_LAYOUT_FROM_HDR(lh)->flags);
642 
643 	p = xdr_inline_decode(&stream, 4);
644 	if (!p)
645 		goto out_sort_mirrors;
646 	for (i=0; i < fls->mirror_array_cnt; i++)
647 		fls->mirror_array[i]->report_interval = be32_to_cpup(p);
648 
649 out_sort_mirrors:
650 	ff_layout_sort_mirrors(fls);
651 	ret = &fls->generic_hdr;
652 	dprintk("<-- %s (success)\n", __func__);
653 out_free_page:
654 	folio_put(scratch);
655 	return ret;
656 out_err_free:
657 	_ff_layout_free_lseg(fls);
658 	ret = ERR_PTR(rc);
659 	dprintk("<-- %s (%d)\n", __func__, rc);
660 	goto out_free_page;
661 }
662 
663 static void
664 ff_layout_free_lseg(struct pnfs_layout_segment *lseg)
665 {
666 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
667 
668 	dprintk("--> %s\n", __func__);
669 
670 	if (lseg->pls_range.iomode == IOMODE_RW) {
671 		struct nfs4_flexfile_layout *ffl;
672 		struct inode *inode;
673 
674 		ffl = FF_LAYOUT_FROM_HDR(lseg->pls_layout);
675 		inode = ffl->generic_hdr.plh_inode;
676 		spin_lock(&inode->i_lock);
677 		pnfs_generic_ds_cinfo_release_lseg(&ffl->commit_info, lseg);
678 		spin_unlock(&inode->i_lock);
679 	}
680 	_ff_layout_free_lseg(fls);
681 }
682 
683 static u32 calc_commit_idx(struct pnfs_layout_segment *lseg,
684 			   u32 mirror_idx, u32 dss_id)
685 {
686 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
687 
688 	return (mirror_idx * flseg->mirror_array[0]->dss_count) + dss_id;
689 }
690 
691 static u32 calc_mirror_idx_from_commit(struct pnfs_layout_segment *lseg,
692 				       u32 commit_index)
693 {
694 	return commit_index / FF_LAYOUT_LSEG(lseg)->mirror_array[0]->dss_count;
695 }
696 
697 static u32 calc_dss_id_from_commit(struct pnfs_layout_segment *lseg,
698 				   u32 commit_index)
699 {
700 	return commit_index % FF_LAYOUT_LSEG(lseg)->mirror_array[0]->dss_count;
701 }
702 
703 static void
704 nfs4_ff_start_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
705 {
706 	/* first IO request? */
707 	if (atomic_inc_return(&timer->n_ops) == 1) {
708 		timer->start_time = now;
709 	}
710 }
711 
712 static ktime_t
713 nfs4_ff_end_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
714 {
715 	ktime_t start;
716 
717 	if (atomic_dec_return(&timer->n_ops) < 0)
718 		WARN_ON_ONCE(1);
719 
720 	start = timer->start_time;
721 	timer->start_time = now;
722 	return ktime_sub(now, start);
723 }
724 
725 static bool
726 nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_mirror *mirror,
727 			    u32 dss_id,
728 			    struct nfs4_ff_layoutstat *layoutstat,
729 			    ktime_t now)
730 {
731 	s64 report_interval = FF_LAYOUTSTATS_REPORT_INTERVAL;
732 	struct nfs4_flexfile_layout *ffl = FF_LAYOUT_FROM_HDR(mirror->layout);
733 
734 	nfs4_ff_start_busy_timer(&layoutstat->busy_timer, now);
735 	if (!mirror->dss[dss_id].start_time)
736 		mirror->dss[dss_id].start_time = now;
737 	if (mirror->report_interval != 0)
738 		report_interval = (s64)mirror->report_interval * 1000LL;
739 	else if (layoutstats_timer != 0)
740 		report_interval = (s64)layoutstats_timer * 1000LL;
741 	if (ktime_to_ms(ktime_sub(now, ffl->last_report_time)) >=
742 			report_interval) {
743 		ffl->last_report_time = now;
744 		return true;
745 	}
746 
747 	return false;
748 }
749 
750 static void
751 nfs4_ff_layout_stat_io_update_requested(struct nfs4_ff_layoutstat *layoutstat,
752 		__u64 requested)
753 {
754 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
755 
756 	iostat->ops_requested++;
757 	iostat->bytes_requested += requested;
758 }
759 
760 static void
761 nfs4_ff_layout_stat_io_update_completed(struct nfs4_ff_layoutstat *layoutstat,
762 		__u64 requested,
763 		__u64 completed,
764 		ktime_t time_completed,
765 		ktime_t time_started)
766 {
767 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
768 	ktime_t completion_time = ktime_sub(time_completed, time_started);
769 	ktime_t timer;
770 
771 	iostat->ops_completed++;
772 	iostat->bytes_completed += completed;
773 	iostat->bytes_not_delivered += requested - completed;
774 
775 	timer = nfs4_ff_end_busy_timer(&layoutstat->busy_timer, time_completed);
776 	iostat->total_busy_time =
777 			ktime_add(iostat->total_busy_time, timer);
778 	iostat->aggregate_completion_time =
779 			ktime_add(iostat->aggregate_completion_time,
780 					completion_time);
781 }
782 
783 static void
784 nfs4_ff_layout_stat_io_start_read(struct inode *inode,
785 		struct nfs4_ff_layout_mirror *mirror,
786 		u32 dss_id,
787 		__u64 requested, ktime_t now)
788 {
789 	bool report;
790 
791 	spin_lock(&mirror->lock);
792 	report = nfs4_ff_layoutstat_start_io(
793 		mirror, dss_id, &mirror->dss[dss_id].read_stat, now);
794 	nfs4_ff_layout_stat_io_update_requested(
795 		&mirror->dss[dss_id].read_stat, requested);
796 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
797 	spin_unlock(&mirror->lock);
798 
799 	if (report)
800 		pnfs_report_layoutstat(inode, nfs_io_gfp_mask());
801 }
802 
803 static void
804 nfs4_ff_layout_stat_io_end_read(struct rpc_task *task,
805 		struct nfs4_ff_layout_mirror *mirror,
806 		u32 dss_id,
807 		__u64 requested,
808 		__u64 completed)
809 {
810 	spin_lock(&mirror->lock);
811 	nfs4_ff_layout_stat_io_update_completed(&mirror->dss[dss_id].read_stat,
812 			requested, completed,
813 			ktime_get(), task->tk_start);
814 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
815 	spin_unlock(&mirror->lock);
816 }
817 
818 static void
819 nfs4_ff_layout_stat_io_start_write(struct inode *inode,
820 		struct nfs4_ff_layout_mirror *mirror,
821 		u32 dss_id,
822 		__u64 requested, ktime_t now)
823 {
824 	bool report;
825 
826 	spin_lock(&mirror->lock);
827 	report = nfs4_ff_layoutstat_start_io(
828 		mirror,
829 		dss_id,
830 		&mirror->dss[dss_id].write_stat,
831 		now);
832 	nfs4_ff_layout_stat_io_update_requested(
833 		&mirror->dss[dss_id].write_stat,
834 		requested);
835 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
836 	spin_unlock(&mirror->lock);
837 
838 	if (report)
839 		pnfs_report_layoutstat(inode, nfs_io_gfp_mask());
840 }
841 
842 static void
843 nfs4_ff_layout_stat_io_end_write(struct rpc_task *task,
844 		struct nfs4_ff_layout_mirror *mirror,
845 		u32 dss_id,
846 		__u64 requested,
847 		__u64 completed,
848 		enum nfs3_stable_how committed)
849 {
850 	if (committed == NFS_UNSTABLE)
851 		requested = completed = 0;
852 
853 	spin_lock(&mirror->lock);
854 	nfs4_ff_layout_stat_io_update_completed(&mirror->dss[dss_id].write_stat,
855 			requested, completed, ktime_get(), task->tk_start);
856 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
857 	spin_unlock(&mirror->lock);
858 }
859 
860 static void
861 ff_layout_mark_ds_unreachable(struct pnfs_layout_segment *lseg, u32 idx, u32 dss_id)
862 {
863 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx, dss_id);
864 
865 	if (devid)
866 		nfs4_mark_deviceid_unavailable(devid);
867 }
868 
869 static void
870 ff_layout_mark_ds_reachable(struct pnfs_layout_segment *lseg, u32 idx, u32 dss_id)
871 {
872 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx, dss_id);
873 
874 	if (devid)
875 		nfs4_mark_deviceid_available(devid);
876 }
877 
878 static struct nfs4_pnfs_ds *
879 ff_layout_choose_ds_for_read(struct pnfs_layout_segment *lseg,
880 			     u32 start_idx, u32 *best_idx,
881 			     u32 offset, u32 *dss_id,
882 			     bool check_device)
883 {
884 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
885 	struct nfs4_ff_layout_mirror *mirror;
886 	struct nfs4_pnfs_ds *ds = ERR_PTR(-EAGAIN);
887 	u32 idx;
888 
889 	/* mirrors are initially sorted by efficiency */
890 	for (idx = start_idx; idx < fls->mirror_array_cnt; idx++) {
891 		mirror = FF_LAYOUT_COMP(lseg, idx);
892 		*dss_id = nfs4_ff_layout_calc_dss_id(
893 			fls->stripe_unit,
894 			fls->mirror_array[idx]->dss_count,
895 			offset);
896 		ds = nfs4_ff_layout_prepare_ds(lseg, mirror, *dss_id, false);
897 		if (IS_ERR(ds))
898 			continue;
899 
900 		if (check_device &&
901 		    nfs4_test_deviceid_unavailable(&mirror->dss[*dss_id].mirror_ds->id_node)) {
902 			// reinitialize the error state in case if this is the last iteration
903 			ds = ERR_PTR(-EINVAL);
904 			continue;
905 		}
906 
907 		*best_idx = idx;
908 		break;
909 	}
910 
911 	return ds;
912 }
913 
914 static struct nfs4_pnfs_ds *
915 ff_layout_choose_any_ds_for_read(struct pnfs_layout_segment *lseg,
916 				 u32 start_idx, u32 *best_idx,
917 				 u32 offset, u32 *dss_id)
918 {
919 	return ff_layout_choose_ds_for_read(lseg, start_idx, best_idx,
920 					    offset, dss_id, false);
921 }
922 
923 static struct nfs4_pnfs_ds *
924 ff_layout_choose_valid_ds_for_read(struct pnfs_layout_segment *lseg,
925 				   u32 start_idx, u32 *best_idx,
926 				   u32 offset, u32 *dss_id)
927 {
928 	return ff_layout_choose_ds_for_read(lseg, start_idx, best_idx,
929 					    offset, dss_id, true);
930 }
931 
932 static struct nfs4_pnfs_ds *
933 ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg,
934 				  u32 start_idx, u32 *best_idx,
935 				  u32 offset, u32 *dss_id)
936 {
937 	struct nfs4_pnfs_ds *ds;
938 
939 	ds = ff_layout_choose_valid_ds_for_read(lseg, start_idx, best_idx,
940 						offset, dss_id);
941 	if (!IS_ERR(ds))
942 		return ds;
943 	return ff_layout_choose_any_ds_for_read(lseg, start_idx, best_idx,
944 						offset, dss_id);
945 }
946 
947 static struct nfs4_pnfs_ds *
948 ff_layout_get_ds_for_read(struct nfs_pageio_descriptor *pgio,
949 			  u32 *best_idx,
950 			  u32 offset,
951 			  u32 *dss_id)
952 {
953 	struct pnfs_layout_segment *lseg = pgio->pg_lseg;
954 	struct nfs4_pnfs_ds *ds;
955 
956 	ds = ff_layout_choose_best_ds_for_read(lseg, pgio->pg_mirror_idx,
957 					       best_idx, offset, dss_id);
958 	if (!IS_ERR(ds) || !pgio->pg_mirror_idx)
959 		return ds;
960 	return ff_layout_choose_best_ds_for_read(lseg, 0, best_idx,
961 						 offset, dss_id);
962 }
963 
964 static void
965 ff_layout_pg_get_read(struct nfs_pageio_descriptor *pgio,
966 		      struct nfs_page *req,
967 		      bool strict_iomode)
968 {
969 	pnfs_put_lseg(pgio->pg_lseg);
970 	pgio->pg_lseg =
971 		pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
972 				   req_offset(req), req->wb_bytes, IOMODE_READ,
973 				   strict_iomode, nfs_io_gfp_mask());
974 	if (IS_ERR(pgio->pg_lseg)) {
975 		pgio->pg_error = PTR_ERR(pgio->pg_lseg);
976 		pgio->pg_lseg = NULL;
977 	}
978 }
979 
980 static bool
981 ff_layout_lseg_is_striped(const struct nfs4_ff_layout_segment *fls)
982 {
983 	return fls->mirror_array[0]->dss_count > 1;
984 }
985 
986 /*
987  * ff_layout_pg_test(). Called by nfs_can_coalesce_requests()
988  *
989  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
990  * of bytes (maximum @req->wb_bytes) that can be coalesced.
991  */
992 static size_t
993 ff_layout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
994 		  struct nfs_page *req)
995 {
996 	unsigned int size;
997 	u64 p_stripe, r_stripe;
998 	u32 stripe_offset;
999 	u64 segment_offset = pgio->pg_lseg->pls_range.offset;
1000 	u32 stripe_unit = FF_LAYOUT_LSEG(pgio->pg_lseg)->stripe_unit;
1001 
1002 	/* calls nfs_generic_pg_test */
1003 	size = pnfs_generic_pg_test(pgio, prev, req);
1004 	if (!size)
1005 		return 0;
1006 	else if (!ff_layout_lseg_is_striped(FF_LAYOUT_LSEG(pgio->pg_lseg)))
1007 		return size;
1008 
1009 	/* see if req and prev are in the same stripe */
1010 	if (prev) {
1011 		p_stripe = (u64)req_offset(prev) - segment_offset;
1012 		r_stripe = (u64)req_offset(req) - segment_offset;
1013 		do_div(p_stripe, stripe_unit);
1014 		do_div(r_stripe, stripe_unit);
1015 
1016 		if (p_stripe != r_stripe)
1017 			return 0;
1018 	}
1019 
1020 	/* calculate remaining bytes in the current stripe */
1021 	div_u64_rem((u64)req_offset(req) - segment_offset,
1022 			stripe_unit,
1023 			&stripe_offset);
1024 	WARN_ON_ONCE(stripe_offset > stripe_unit);
1025 	if (stripe_offset >= stripe_unit)
1026 		return 0;
1027 	return min(stripe_unit - (unsigned int)stripe_offset, size);
1028 }
1029 
1030 static void
1031 ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
1032 			struct nfs_page *req)
1033 {
1034 	struct nfs_pgio_mirror *pgm;
1035 	struct nfs4_ff_layout_mirror *mirror;
1036 	struct nfs4_pnfs_ds *ds;
1037 	u32 ds_idx, dss_id;
1038 
1039 	if (NFS_SERVER(pgio->pg_inode)->flags &
1040 			(NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR))
1041 		pgio->pg_maxretrans = io_maxretrans;
1042 retry:
1043 	pnfs_generic_pg_check_layout(pgio, req);
1044 	/* Use full layout for now */
1045 	if (!pgio->pg_lseg) {
1046 		ff_layout_pg_get_read(pgio, req, false);
1047 		if (!pgio->pg_lseg)
1048 			goto out_nolseg;
1049 	}
1050 	if (ff_layout_avoid_read_on_rw(pgio->pg_lseg)) {
1051 		ff_layout_pg_get_read(pgio, req, true);
1052 		if (!pgio->pg_lseg)
1053 			goto out_nolseg;
1054 	}
1055 	/* Reset wb_nio, since getting layout segment was successful */
1056 	req->wb_nio = 0;
1057 
1058 	ds = ff_layout_get_ds_for_read(pgio, &ds_idx,
1059 				       req_offset(req), &dss_id);
1060 	if (IS_ERR(ds)) {
1061 		if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
1062 			goto out_mds;
1063 		pnfs_generic_pg_cleanup(pgio);
1064 		/* Sleep for 1 second before retrying */
1065 		ssleep(1);
1066 		goto retry;
1067 	}
1068 
1069 	mirror = FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx);
1070 	pgm = &pgio->pg_mirrors[0];
1071 	pgm->pg_bsize = mirror->dss[dss_id].mirror_ds->ds_versions[0].rsize;
1072 
1073 	pgio->pg_mirror_idx = ds_idx;
1074 	return;
1075 out_nolseg:
1076 	if (pgio->pg_error < 0) {
1077 		if (pgio->pg_error != -EAGAIN)
1078 			return;
1079 		/* Retry getting layout segment if lower layer returned -EAGAIN */
1080 		if (pgio->pg_maxretrans && req->wb_nio++ > pgio->pg_maxretrans) {
1081 			if (NFS_SERVER(pgio->pg_inode)->flags & NFS_MOUNT_SOFTERR)
1082 				pgio->pg_error = -ETIMEDOUT;
1083 			else
1084 				pgio->pg_error = -EIO;
1085 			return;
1086 		}
1087 		pgio->pg_error = 0;
1088 		/* Sleep for 1 second before retrying */
1089 		ssleep(1);
1090 		goto retry;
1091 	}
1092 out_mds:
1093 	trace_pnfs_mds_fallback_pg_init_read(pgio->pg_inode,
1094 			0, NFS4_MAX_UINT64, IOMODE_READ,
1095 			NFS_I(pgio->pg_inode)->layout,
1096 			pgio->pg_lseg);
1097 	pgio->pg_maxretrans = 0;
1098 	nfs_pageio_reset_read_mds(pgio);
1099 }
1100 
1101 static void
1102 ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
1103 			struct nfs_page *req)
1104 {
1105 	struct nfs4_ff_layout_mirror *mirror;
1106 	struct nfs_pgio_mirror *pgm;
1107 	struct nfs4_pnfs_ds *ds;
1108 	u32 i, dss_id;
1109 
1110 retry:
1111 	pnfs_generic_pg_check_layout(pgio, req);
1112 	if (!pgio->pg_lseg) {
1113 		pgio->pg_lseg =
1114 			pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
1115 					   req_offset(req), req->wb_bytes,
1116 					   IOMODE_RW, false, nfs_io_gfp_mask());
1117 		if (IS_ERR(pgio->pg_lseg)) {
1118 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
1119 			pgio->pg_lseg = NULL;
1120 			return;
1121 		}
1122 	}
1123 	/* If no lseg, fall back to write through mds */
1124 	if (pgio->pg_lseg == NULL)
1125 		goto out_mds;
1126 
1127 	/* Use a direct mapping of ds_idx to pgio mirror_idx */
1128 	if (pgio->pg_mirror_count != FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg))
1129 		goto out_eagain;
1130 
1131 	for (i = 0; i < pgio->pg_mirror_count; i++) {
1132 		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
1133 		dss_id = nfs4_ff_layout_calc_dss_id(
1134 			FF_LAYOUT_LSEG(pgio->pg_lseg)->stripe_unit,
1135 			mirror->dss_count,
1136 			req_offset(req));
1137 		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, mirror,
1138 					       dss_id, true);
1139 		if (IS_ERR(ds)) {
1140 			if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
1141 				goto out_mds;
1142 			pnfs_generic_pg_cleanup(pgio);
1143 			/* Sleep for 1 second before retrying */
1144 			ssleep(1);
1145 			goto retry;
1146 		}
1147 		pgm = &pgio->pg_mirrors[i];
1148 		pgm->pg_bsize = mirror->dss[dss_id].mirror_ds->ds_versions[0].wsize;
1149 	}
1150 
1151 	if (NFS_SERVER(pgio->pg_inode)->flags &
1152 			(NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR))
1153 		pgio->pg_maxretrans = io_maxretrans;
1154 	return;
1155 out_eagain:
1156 	pnfs_generic_pg_cleanup(pgio);
1157 	pgio->pg_error = -EAGAIN;
1158 	return;
1159 out_mds:
1160 	trace_pnfs_mds_fallback_pg_init_write(pgio->pg_inode,
1161 			0, NFS4_MAX_UINT64, IOMODE_RW,
1162 			NFS_I(pgio->pg_inode)->layout,
1163 			pgio->pg_lseg);
1164 	pgio->pg_maxretrans = 0;
1165 	nfs_pageio_reset_write_mds(pgio);
1166 	pgio->pg_error = -EAGAIN;
1167 }
1168 
1169 static unsigned int
1170 ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
1171 				    struct nfs_page *req)
1172 {
1173 	if (!pgio->pg_lseg) {
1174 		pgio->pg_lseg =
1175 			pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
1176 					   req_offset(req), req->wb_bytes,
1177 					   IOMODE_RW, false, nfs_io_gfp_mask());
1178 		if (IS_ERR(pgio->pg_lseg)) {
1179 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
1180 			pgio->pg_lseg = NULL;
1181 			goto out;
1182 		}
1183 	}
1184 	if (pgio->pg_lseg)
1185 		return FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg);
1186 
1187 	trace_pnfs_mds_fallback_pg_get_mirror_count(pgio->pg_inode,
1188 			0, NFS4_MAX_UINT64, IOMODE_RW,
1189 			NFS_I(pgio->pg_inode)->layout,
1190 			pgio->pg_lseg);
1191 	if (NFS_I(pgio->pg_inode)->layout &&
1192 	    ff_layout_hdr_no_fallback_to_mds(NFS_I(pgio->pg_inode)->layout)) {
1193 		/*
1194 		 * FF_FLAGS_NO_IO_THRU_MDS: no current lseg but the server's
1195 		 * policy forbids MDS fallback.  Surface -EAGAIN so writeback
1196 		 * retries rather than silently issuing the WRITE via MDS.
1197 		 */
1198 		pgio->pg_error = -EAGAIN;
1199 		goto out;
1200 	}
1201 	/* no lseg means that pnfs is not in use, so no mirroring here */
1202 	nfs_pageio_reset_write_mds(pgio);
1203 out:
1204 	return 1;
1205 }
1206 
1207 static u32
1208 ff_layout_pg_set_mirror_write(struct nfs_pageio_descriptor *desc, u32 idx)
1209 {
1210 	u32 old = desc->pg_mirror_idx;
1211 
1212 	desc->pg_mirror_idx = idx;
1213 	return old;
1214 }
1215 
1216 static struct nfs_pgio_mirror *
1217 ff_layout_pg_get_mirror_write(struct nfs_pageio_descriptor *desc, u32 idx)
1218 {
1219 	return &desc->pg_mirrors[idx];
1220 }
1221 
1222 static const struct nfs_pageio_ops ff_layout_pg_read_ops = {
1223 	.pg_init = ff_layout_pg_init_read,
1224 	.pg_test = ff_layout_pg_test,
1225 	.pg_doio = pnfs_generic_pg_readpages,
1226 	.pg_cleanup = pnfs_generic_pg_cleanup,
1227 };
1228 
1229 static const struct nfs_pageio_ops ff_layout_pg_write_ops = {
1230 	.pg_init = ff_layout_pg_init_write,
1231 	.pg_test = ff_layout_pg_test,
1232 	.pg_doio = pnfs_generic_pg_writepages,
1233 	.pg_get_mirror_count = ff_layout_pg_get_mirror_count_write,
1234 	.pg_cleanup = pnfs_generic_pg_cleanup,
1235 	.pg_get_mirror = ff_layout_pg_get_mirror_write,
1236 	.pg_set_mirror = ff_layout_pg_set_mirror_write,
1237 };
1238 
1239 static void ff_layout_reset_write(struct nfs_pgio_header *hdr, bool retry_pnfs)
1240 {
1241 	struct rpc_task *task = &hdr->task;
1242 
1243 	pnfs_layoutcommit_inode(hdr->inode, false);
1244 
1245 	if (retry_pnfs) {
1246 		dprintk("%s Reset task %5u for i/o through pNFS "
1247 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1248 			hdr->task.tk_pid,
1249 			hdr->inode->i_sb->s_id,
1250 			(unsigned long long)hdr->inode->i_ino,
1251 			hdr->args.count,
1252 			(unsigned long long)hdr->args.offset);
1253 
1254 		hdr->completion_ops->reschedule_io(hdr);
1255 		return;
1256 	}
1257 
1258 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1259 		dprintk("%s Reset task %5u for i/o through MDS "
1260 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1261 			hdr->task.tk_pid,
1262 			hdr->inode->i_sb->s_id,
1263 			(unsigned long long)hdr->inode->i_ino,
1264 			hdr->args.count,
1265 			(unsigned long long)hdr->args.offset);
1266 
1267 		trace_pnfs_mds_fallback_write_done(hdr->inode,
1268 				hdr->args.offset, hdr->args.count,
1269 				IOMODE_RW, NFS_I(hdr->inode)->layout,
1270 				hdr->lseg);
1271 		task->tk_status = pnfs_write_done_resend_to_mds(hdr);
1272 	}
1273 }
1274 
1275 static void ff_layout_resend_pnfs_read(struct nfs_pgio_header *hdr)
1276 {
1277 	u32 idx = hdr->pgio_mirror_idx + 1;
1278 	u32 new_idx = 0;
1279 	u32 dss_id = 0;
1280 	struct nfs4_pnfs_ds *ds;
1281 
1282 	ds = ff_layout_choose_any_ds_for_read(hdr->lseg, idx, &new_idx,
1283 					      hdr->args.offset, &dss_id);
1284 	if (IS_ERR(ds))
1285 		pnfs_error_mark_layout_for_return(hdr->inode, hdr->lseg);
1286 	else
1287 		ff_layout_send_layouterror(hdr->lseg);
1288 	pnfs_read_resend_pnfs(hdr, new_idx);
1289 }
1290 
1291 static void ff_layout_reset_read(struct nfs_pgio_header *hdr)
1292 {
1293 	struct rpc_task *task = &hdr->task;
1294 
1295 	pnfs_layoutcommit_inode(hdr->inode, false);
1296 	pnfs_error_mark_layout_for_return(hdr->inode, hdr->lseg);
1297 
1298 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1299 		dprintk("%s Reset task %5u for i/o through MDS "
1300 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1301 			hdr->task.tk_pid,
1302 			hdr->inode->i_sb->s_id,
1303 			(unsigned long long)hdr->inode->i_ino,
1304 			hdr->args.count,
1305 			(unsigned long long)hdr->args.offset);
1306 
1307 		trace_pnfs_mds_fallback_read_done(hdr->inode,
1308 				hdr->args.offset, hdr->args.count,
1309 				IOMODE_READ, NFS_I(hdr->inode)->layout,
1310 				hdr->lseg);
1311 		task->tk_status = pnfs_read_done_resend_to_mds(hdr);
1312 	}
1313 }
1314 
1315 static int ff_layout_async_handle_error_v4(struct rpc_task *task,
1316 					   u32 op_status,
1317 					   struct nfs4_state *state,
1318 					   struct nfs_client *clp,
1319 					   struct pnfs_layout_segment *lseg,
1320 					   u32 idx, u32 dss_id)
1321 {
1322 	struct pnfs_layout_hdr *lo = lseg->pls_layout;
1323 	struct inode *inode = lo->plh_inode;
1324 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx, dss_id);
1325 	struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
1326 
1327 	switch (op_status) {
1328 	case NFS4_OK:
1329 	case NFS4ERR_NXIO:
1330 		break;
1331 	case NFSERR_PERM:
1332 		if (!task->tk_xprt)
1333 			break;
1334 		xprt_force_disconnect(task->tk_xprt);
1335 		goto out_retry;
1336 	case NFS4ERR_BADSESSION:
1337 	case NFS4ERR_BADSLOT:
1338 	case NFS4ERR_BAD_HIGH_SLOT:
1339 	case NFS4ERR_DEADSESSION:
1340 	case NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
1341 	case NFS4ERR_SEQ_FALSE_RETRY:
1342 	case NFS4ERR_SEQ_MISORDERED:
1343 		dprintk("%s ERROR %d, Reset session. Exchangeid "
1344 			"flags 0x%x\n", __func__, task->tk_status,
1345 			clp->cl_exchange_flags);
1346 		nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
1347 		goto out_retry;
1348 	case NFS4ERR_DELAY:
1349 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1350 		fallthrough;
1351 	case NFS4ERR_GRACE:
1352 		rpc_delay(task, FF_LAYOUT_POLL_RETRY_MAX);
1353 		goto out_retry;
1354 	case NFS4ERR_RETRY_UNCACHED_REP:
1355 		goto out_retry;
1356 	/* Invalidate Layout errors */
1357 	case NFS4ERR_PNFS_NO_LAYOUT:
1358 	case NFS4ERR_STALE:
1359 	case NFS4ERR_BADHANDLE:
1360 	case NFS4ERR_ISDIR:
1361 	case NFS4ERR_FHEXPIRED:
1362 	case NFS4ERR_WRONG_TYPE:
1363 		dprintk("%s Invalid layout error %d\n", __func__,
1364 			task->tk_status);
1365 		/*
1366 		 * Destroy layout so new i/o will get a new layout.
1367 		 * Layout will not be destroyed until all current lseg
1368 		 * references are put. Mark layout as invalid to resend failed
1369 		 * i/o and all i/o waiting on the slot table to the MDS until
1370 		 * layout is destroyed and a new valid layout is obtained.
1371 		 */
1372 		pnfs_destroy_layout(NFS_I(inode));
1373 		rpc_wake_up(&tbl->slot_tbl_waitq);
1374 		goto reset;
1375 	default:
1376 		break;
1377 	}
1378 
1379 	switch (task->tk_status) {
1380 	/* RPC connection errors */
1381 	case -ENETDOWN:
1382 	case -ENETUNREACH:
1383 		if (test_bit(NFS_CS_NETUNREACH_FATAL, &clp->cl_flags))
1384 			return -NFS4ERR_FATAL_IOERROR;
1385 		fallthrough;
1386 	case -ECONNREFUSED:
1387 	case -EHOSTDOWN:
1388 	case -EHOSTUNREACH:
1389 	case -EIO:
1390 	case -ETIMEDOUT:
1391 	case -EPIPE:
1392 	case -EPROTO:
1393 	case -ENODEV:
1394 		dprintk("%s DS connection error %d\n", __func__,
1395 			task->tk_status);
1396 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1397 				&devid->deviceid);
1398 		rpc_wake_up(&tbl->slot_tbl_waitq);
1399 		break;
1400 	default:
1401 		break;
1402 	}
1403 
1404 	if (ff_layout_avoid_mds_available_ds(lseg))
1405 		return -NFS4ERR_RESET_TO_PNFS;
1406 reset:
1407 	dprintk("%s Retry through MDS. Error %d\n", __func__,
1408 		task->tk_status);
1409 	return -NFS4ERR_RESET_TO_MDS;
1410 
1411 out_retry:
1412 	task->tk_status = 0;
1413 	return -EAGAIN;
1414 }
1415 
1416 /* Retry all errors through either pNFS or MDS except for -EJUKEBOX */
1417 static int ff_layout_async_handle_error_v3(struct rpc_task *task,
1418 					   u32 op_status,
1419 					   struct nfs_client *clp,
1420 					   struct pnfs_layout_segment *lseg,
1421 					   u32 idx, u32 dss_id)
1422 {
1423 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx, dss_id);
1424 
1425 	switch (op_status) {
1426 	case NFS_OK:
1427 	case NFSERR_NXIO:
1428 		break;
1429 	case NFSERR_PERM:
1430 		if (!task->tk_xprt)
1431 			break;
1432 		xprt_force_disconnect(task->tk_xprt);
1433 		goto out_retry;
1434 	case NFSERR_ACCES:
1435 	case NFSERR_BADHANDLE:
1436 	case NFSERR_FBIG:
1437 	case NFSERR_IO:
1438 	case NFSERR_NOSPC:
1439 	case NFSERR_ROFS:
1440 	case NFSERR_STALE:
1441 		goto out_reset_to_pnfs;
1442 	case NFSERR_JUKEBOX:
1443 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1444 		goto out_retry;
1445 	default:
1446 		break;
1447 	}
1448 
1449 	switch (task->tk_status) {
1450 	/* File access problems. Don't mark the device as unavailable */
1451 	case -EACCES:
1452 	case -ESTALE:
1453 	case -EISDIR:
1454 	case -EBADHANDLE:
1455 	case -ELOOP:
1456 	case -ENOSPC:
1457 		break;
1458 	case -EJUKEBOX:
1459 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1460 		goto out_retry;
1461 	case -ENETDOWN:
1462 	case -ENETUNREACH:
1463 		if (test_bit(NFS_CS_NETUNREACH_FATAL, &clp->cl_flags))
1464 			return -NFS4ERR_FATAL_IOERROR;
1465 		fallthrough;
1466 	default:
1467 		dprintk("%s DS connection error %d\n", __func__,
1468 			task->tk_status);
1469 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1470 				&devid->deviceid);
1471 	}
1472 out_reset_to_pnfs:
1473 	/* FIXME: Need to prevent infinite looping here. */
1474 	return -NFS4ERR_RESET_TO_PNFS;
1475 out_retry:
1476 	task->tk_status = 0;
1477 	rpc_restart_call_prepare(task);
1478 	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
1479 	return -EAGAIN;
1480 }
1481 
1482 static int ff_layout_async_handle_error(struct rpc_task *task,
1483 					u32 op_status,
1484 					struct nfs4_state *state,
1485 					struct nfs_client *clp,
1486 					struct pnfs_layout_segment *lseg,
1487 					u32 idx, u32 dss_id)
1488 {
1489 	int vers = clp->cl_nfs_mod->rpc_vers->number;
1490 
1491 	if (task->tk_status >= 0) {
1492 		ff_layout_mark_ds_reachable(lseg, idx, dss_id);
1493 		return 0;
1494 	}
1495 
1496 	/* Handle the case of an invalid layout segment */
1497 	if (!pnfs_is_valid_lseg(lseg))
1498 		return -NFS4ERR_RESET_TO_PNFS;
1499 
1500 	switch (vers) {
1501 	case 3:
1502 		return ff_layout_async_handle_error_v3(task, op_status, clp,
1503 						       lseg, idx, dss_id);
1504 	case 4:
1505 		return ff_layout_async_handle_error_v4(task, op_status, state,
1506 						       clp, lseg, idx, dss_id);
1507 	default:
1508 		/* should never happen */
1509 		WARN_ON_ONCE(1);
1510 		return 0;
1511 	}
1512 }
1513 
1514 static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg,
1515 					u32 idx, u32 dss_id, u64 offset, u64 length,
1516 					u32 *op_status, int opnum, int error)
1517 {
1518 	struct nfs4_ff_layout_mirror *mirror;
1519 	u32 status = *op_status;
1520 	int err;
1521 
1522 	if (status == 0) {
1523 		switch (error) {
1524 		case -ETIMEDOUT:
1525 		case -EPFNOSUPPORT:
1526 		case -EPROTONOSUPPORT:
1527 		case -EOPNOTSUPP:
1528 		case -EINVAL:
1529 		case -ECONNREFUSED:
1530 		case -ECONNRESET:
1531 		case -EHOSTDOWN:
1532 		case -EHOSTUNREACH:
1533 		case -ENETDOWN:
1534 		case -ENETUNREACH:
1535 		case -EADDRINUSE:
1536 		case -ENOBUFS:
1537 		case -EPIPE:
1538 		case -EPERM:
1539 		case -EPROTO:
1540 		case -ENODEV:
1541 			*op_status = status = NFS4ERR_NXIO;
1542 			break;
1543 		case -EACCES:
1544 			*op_status = status = NFS4ERR_ACCESS;
1545 			break;
1546 		default:
1547 			return;
1548 		}
1549 	}
1550 
1551 	mirror = FF_LAYOUT_COMP(lseg, idx);
1552 	err = ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),
1553 				       mirror, dss_id, offset, length, status, opnum,
1554 				       nfs_io_gfp_mask());
1555 
1556 	switch (status) {
1557 	case NFS4ERR_DELAY:
1558 	case NFS4ERR_GRACE:
1559 	case NFS4ERR_PERM:
1560 		break;
1561 	case NFS4ERR_NXIO:
1562 		ff_layout_mark_ds_unreachable(lseg, idx, dss_id);
1563 		/*
1564 		 * Don't return the layout if this is a read and we still
1565 		 * have layouts to try
1566 		 */
1567 		if (opnum == OP_READ)
1568 			break;
1569 		fallthrough;
1570 	default:
1571 		pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode,
1572 						  lseg);
1573 	}
1574 
1575 	dprintk("%s: err %d op %d status %u\n", __func__, err, opnum, status);
1576 }
1577 
1578 /* NFS_PROTO call done callback routines */
1579 static int ff_layout_read_done_cb(struct rpc_task *task,
1580 				struct nfs_pgio_header *hdr)
1581 {
1582 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(hdr->lseg);
1583 	u32 dss_id = nfs4_ff_layout_calc_dss_id(
1584 		flseg->stripe_unit,
1585 		flseg->mirror_array[hdr->pgio_mirror_idx]->dss_count,
1586 		hdr->args.offset);
1587 	int err;
1588 
1589 	if (task->tk_status < 0) {
1590 		ff_layout_io_track_ds_error(hdr->lseg,
1591 					    hdr->pgio_mirror_idx, dss_id,
1592 					    hdr->args.offset, hdr->args.count,
1593 					    &hdr->res.op_status, OP_READ,
1594 					    task->tk_status);
1595 		trace_ff_layout_read_error(hdr, task->tk_status);
1596 	}
1597 
1598 	err = ff_layout_async_handle_error(task, hdr->res.op_status,
1599 					   hdr->args.context->state,
1600 					   hdr->ds_clp, hdr->lseg,
1601 					   hdr->pgio_mirror_idx,
1602 					   dss_id);
1603 
1604 	trace_nfs4_pnfs_read(hdr, err);
1605 	clear_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1606 	clear_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1607 	switch (err) {
1608 	case -NFS4ERR_RESET_TO_PNFS:
1609 		set_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1610 		return task->tk_status;
1611 	case -NFS4ERR_RESET_TO_MDS:
1612 		set_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1613 		return task->tk_status;
1614 	case -EAGAIN:
1615 		goto out_eagain;
1616 	case -NFS4ERR_FATAL_IOERROR:
1617 		task->tk_status = -EIO;
1618 		return 0;
1619 	}
1620 
1621 	return 0;
1622 out_eagain:
1623 	rpc_restart_call_prepare(task);
1624 	return -EAGAIN;
1625 }
1626 
1627 static bool
1628 ff_layout_need_layoutcommit(struct pnfs_layout_segment *lseg)
1629 {
1630 	return !(FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_LAYOUTCOMMIT);
1631 }
1632 
1633 /*
1634  * We reference the rpc_cred of the first WRITE that triggers the need for
1635  * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
1636  * rfc5661 is not clear about which credential should be used.
1637  *
1638  * Flexlayout client should treat DS replied FILE_SYNC as DATA_SYNC, so
1639  * to follow http://www.rfc-editor.org/errata_search.php?rfc=5661&eid=2751
1640  * we always send layoutcommit after DS writes.
1641  */
1642 static void
1643 ff_layout_set_layoutcommit(struct inode *inode,
1644 		struct pnfs_layout_segment *lseg,
1645 		loff_t end_offset)
1646 {
1647 	if (!ff_layout_need_layoutcommit(lseg))
1648 		return;
1649 
1650 	pnfs_set_layoutcommit(inode, lseg, end_offset);
1651 	dprintk("%s inode %llu pls_end_pos %llu\n", __func__, inode->i_ino,
1652 		(unsigned long long) NFS_I(inode)->layout->plh_lwb);
1653 }
1654 
1655 static void ff_layout_read_record_layoutstats_start(struct rpc_task *task,
1656 		struct nfs_pgio_header *hdr)
1657 {
1658 	struct nfs4_ff_layout_mirror *mirror;
1659 	u32 dss_id;
1660 
1661 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1662 		return;
1663 
1664 	mirror = FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx);
1665 	dss_id = nfs4_ff_layout_calc_dss_id(
1666 		FF_LAYOUT_LSEG(hdr->lseg)->stripe_unit,
1667 		mirror->dss_count,
1668 		hdr->args.offset);
1669 
1670 	nfs4_ff_layout_stat_io_start_read(
1671 		hdr->inode,
1672 		mirror,
1673 		dss_id,
1674 		hdr->args.count,
1675 		task->tk_start);
1676 }
1677 
1678 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
1679 		struct nfs_pgio_header *hdr)
1680 {
1681 	struct nfs4_ff_layout_mirror *mirror;
1682 	u32 dss_id;
1683 
1684 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1685 		return;
1686 
1687 	mirror = FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx);
1688 	dss_id = nfs4_ff_layout_calc_dss_id(
1689 		FF_LAYOUT_LSEG(hdr->lseg)->stripe_unit,
1690 		mirror->dss_count,
1691 		hdr->args.offset);
1692 
1693 	nfs4_ff_layout_stat_io_end_read(
1694 		task,
1695 		mirror,
1696 		dss_id,
1697 		hdr->args.count,
1698 		hdr->res.count);
1699 	set_bit(NFS_LSEG_LAYOUTRETURN, &hdr->lseg->pls_flags);
1700 }
1701 
1702 static int ff_layout_read_prepare_common(struct rpc_task *task,
1703 					 struct nfs_pgio_header *hdr)
1704 {
1705 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1706 		rpc_exit(task, -EIO);
1707 		return -EIO;
1708 	}
1709 
1710 	if (!pnfs_is_valid_lseg(hdr->lseg)) {
1711 		rpc_exit(task, -EAGAIN);
1712 		return -EAGAIN;
1713 	}
1714 
1715 	ff_layout_read_record_layoutstats_start(task, hdr);
1716 	return 0;
1717 }
1718 
1719 /*
1720  * Call ops for the async read/write cases
1721  * In the case of dense layouts, the offset needs to be reset to its
1722  * original value.
1723  */
1724 static void ff_layout_read_prepare_v3(struct rpc_task *task, void *data)
1725 {
1726 	struct nfs_pgio_header *hdr = data;
1727 
1728 	if (ff_layout_read_prepare_common(task, hdr))
1729 		return;
1730 
1731 	rpc_call_start(task);
1732 }
1733 
1734 static void ff_layout_read_prepare_v4(struct rpc_task *task, void *data)
1735 {
1736 	struct nfs_pgio_header *hdr = data;
1737 
1738 	if (nfs4_setup_sequence(hdr->ds_clp,
1739 				&hdr->args.seq_args,
1740 				&hdr->res.seq_res,
1741 				task))
1742 		return;
1743 
1744 	ff_layout_read_prepare_common(task, hdr);
1745 }
1746 
1747 static void ff_layout_read_call_done(struct rpc_task *task, void *data)
1748 {
1749 	struct nfs_pgio_header *hdr = data;
1750 
1751 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1752 	    task->tk_status == 0) {
1753 		nfs4_sequence_done(task, &hdr->res.seq_res);
1754 		return;
1755 	}
1756 
1757 	/* Note this may cause RPC to be resent */
1758 	hdr->mds_ops->rpc_call_done(task, hdr);
1759 }
1760 
1761 static void ff_layout_read_count_stats(struct rpc_task *task, void *data)
1762 {
1763 	struct nfs_pgio_header *hdr = data;
1764 
1765 	ff_layout_read_record_layoutstats_done(task, hdr);
1766 	rpc_count_iostats_metrics(task,
1767 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_READ]);
1768 }
1769 
1770 static void ff_layout_read_release(void *data)
1771 {
1772 	struct nfs_pgio_header *hdr = data;
1773 
1774 	ff_layout_read_record_layoutstats_done(&hdr->task, hdr);
1775 	if (test_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags))
1776 		ff_layout_resend_pnfs_read(hdr);
1777 	else if (test_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags))
1778 		ff_layout_reset_read(hdr);
1779 	pnfs_generic_rw_release(data);
1780 }
1781 
1782 
1783 static int ff_layout_write_done_cb(struct rpc_task *task,
1784 				struct nfs_pgio_header *hdr)
1785 {
1786 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(hdr->lseg);
1787 	u32 dss_id = nfs4_ff_layout_calc_dss_id(
1788 		flseg->stripe_unit,
1789 		flseg->mirror_array[hdr->pgio_mirror_idx]->dss_count,
1790 		hdr->args.offset);
1791 	loff_t end_offs = 0;
1792 	int err;
1793 
1794 	if (task->tk_status < 0) {
1795 		ff_layout_io_track_ds_error(hdr->lseg,
1796 					    hdr->pgio_mirror_idx, dss_id,
1797 					    hdr->args.offset, hdr->args.count,
1798 					    &hdr->res.op_status, OP_WRITE,
1799 					    task->tk_status);
1800 		trace_ff_layout_write_error(hdr, task->tk_status);
1801 	}
1802 
1803 	err = ff_layout_async_handle_error(task, hdr->res.op_status,
1804 					   hdr->args.context->state,
1805 					   hdr->ds_clp, hdr->lseg,
1806 					   hdr->pgio_mirror_idx,
1807 					   dss_id);
1808 
1809 	trace_nfs4_pnfs_write(hdr, err);
1810 	clear_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1811 	clear_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1812 	switch (err) {
1813 	case -NFS4ERR_RESET_TO_PNFS:
1814 		set_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1815 		return task->tk_status;
1816 	case -NFS4ERR_RESET_TO_MDS:
1817 		set_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1818 		return task->tk_status;
1819 	case -EAGAIN:
1820 		return -EAGAIN;
1821 	case -NFS4ERR_FATAL_IOERROR:
1822 		task->tk_status = -EIO;
1823 		return 0;
1824 	}
1825 
1826 	if (hdr->res.verf->committed == NFS_FILE_SYNC ||
1827 	    hdr->res.verf->committed == NFS_DATA_SYNC)
1828 		end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
1829 
1830 	/* Note: if the write is unstable, don't set end_offs until commit */
1831 	ff_layout_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
1832 
1833 	/* zero out fattr since we don't care DS attr at all */
1834 	hdr->fattr.valid = 0;
1835 	if (task->tk_status >= 0)
1836 		nfs_writeback_update_inode(hdr);
1837 
1838 	return 0;
1839 }
1840 
1841 static int ff_layout_commit_done_cb(struct rpc_task *task,
1842 				     struct nfs_commit_data *data)
1843 {
1844 	int err;
1845 	u32 idx = calc_mirror_idx_from_commit(data->lseg, data->ds_commit_index);
1846 	u32 dss_id = calc_dss_id_from_commit(data->lseg, data->ds_commit_index);
1847 
1848 	if (task->tk_status < 0) {
1849 		ff_layout_io_track_ds_error(data->lseg, idx, dss_id,
1850 					    data->args.offset, data->args.count,
1851 					    &data->res.op_status, OP_COMMIT,
1852 					    task->tk_status);
1853 		trace_ff_layout_commit_error(data, task->tk_status);
1854 	}
1855 
1856 	err = ff_layout_async_handle_error(task, data->res.op_status,
1857 					   NULL, data->ds_clp, data->lseg, idx,
1858 					   dss_id);
1859 
1860 	trace_nfs4_pnfs_commit_ds(data, err);
1861 	switch (err) {
1862 	case -NFS4ERR_RESET_TO_PNFS:
1863 		pnfs_generic_prepare_to_resend_writes(data);
1864 		return -EAGAIN;
1865 	case -NFS4ERR_RESET_TO_MDS:
1866 		pnfs_generic_prepare_to_resend_writes(data);
1867 		return -EAGAIN;
1868 	case -EAGAIN:
1869 		rpc_restart_call_prepare(task);
1870 		return -EAGAIN;
1871 	case -NFS4ERR_FATAL_IOERROR:
1872 		task->tk_status = -EIO;
1873 		return 0;
1874 	}
1875 
1876 	ff_layout_set_layoutcommit(data->inode, data->lseg, data->lwb);
1877 	return 0;
1878 }
1879 
1880 static void ff_layout_write_record_layoutstats_start(struct rpc_task *task,
1881 		struct nfs_pgio_header *hdr)
1882 {
1883 	struct nfs4_ff_layout_mirror *mirror;
1884 	u32 dss_id;
1885 
1886 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1887 		return;
1888 
1889 	mirror = FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx);
1890 	dss_id = nfs4_ff_layout_calc_dss_id(
1891 		FF_LAYOUT_LSEG(hdr->lseg)->stripe_unit,
1892 		mirror->dss_count,
1893 		hdr->args.offset);
1894 
1895 	nfs4_ff_layout_stat_io_start_write(
1896 		hdr->inode,
1897 		mirror,
1898 		dss_id,
1899 		hdr->args.count,
1900 		task->tk_start);
1901 }
1902 
1903 static void ff_layout_write_record_layoutstats_done(struct rpc_task *task,
1904 		struct nfs_pgio_header *hdr)
1905 {
1906 	struct nfs4_ff_layout_mirror *mirror;
1907 	u32 dss_id;
1908 
1909 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1910 		return;
1911 
1912 	mirror = FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx);
1913 	dss_id = nfs4_ff_layout_calc_dss_id(
1914 		FF_LAYOUT_LSEG(hdr->lseg)->stripe_unit,
1915 		mirror->dss_count,
1916 		hdr->args.offset);
1917 
1918 	nfs4_ff_layout_stat_io_end_write(
1919 		task,
1920 		mirror,
1921 		dss_id,
1922 		hdr->args.count,
1923 		hdr->res.count,
1924 		hdr->res.verf->committed);
1925 	set_bit(NFS_LSEG_LAYOUTRETURN, &hdr->lseg->pls_flags);
1926 }
1927 
1928 static int ff_layout_write_prepare_common(struct rpc_task *task,
1929 					  struct nfs_pgio_header *hdr)
1930 {
1931 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1932 		rpc_exit(task, -EIO);
1933 		return -EIO;
1934 	}
1935 
1936 	if (!pnfs_is_valid_lseg(hdr->lseg)) {
1937 		rpc_exit(task, -EAGAIN);
1938 		return -EAGAIN;
1939 	}
1940 
1941 	ff_layout_write_record_layoutstats_start(task, hdr);
1942 	return 0;
1943 }
1944 
1945 static void ff_layout_write_prepare_v3(struct rpc_task *task, void *data)
1946 {
1947 	struct nfs_pgio_header *hdr = data;
1948 
1949 	if (ff_layout_write_prepare_common(task, hdr))
1950 		return;
1951 
1952 	rpc_call_start(task);
1953 }
1954 
1955 static void ff_layout_write_prepare_v4(struct rpc_task *task, void *data)
1956 {
1957 	struct nfs_pgio_header *hdr = data;
1958 
1959 	if (nfs4_setup_sequence(hdr->ds_clp,
1960 				&hdr->args.seq_args,
1961 				&hdr->res.seq_res,
1962 				task))
1963 		return;
1964 
1965 	ff_layout_write_prepare_common(task, hdr);
1966 }
1967 
1968 static void ff_layout_write_call_done(struct rpc_task *task, void *data)
1969 {
1970 	struct nfs_pgio_header *hdr = data;
1971 
1972 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1973 	    task->tk_status == 0) {
1974 		nfs4_sequence_done(task, &hdr->res.seq_res);
1975 		return;
1976 	}
1977 
1978 	/* Note this may cause RPC to be resent */
1979 	hdr->mds_ops->rpc_call_done(task, hdr);
1980 }
1981 
1982 static void ff_layout_write_count_stats(struct rpc_task *task, void *data)
1983 {
1984 	struct nfs_pgio_header *hdr = data;
1985 
1986 	ff_layout_write_record_layoutstats_done(task, hdr);
1987 	rpc_count_iostats_metrics(task,
1988 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_WRITE]);
1989 }
1990 
1991 static void ff_layout_write_release(void *data)
1992 {
1993 	struct nfs_pgio_header *hdr = data;
1994 
1995 	ff_layout_write_record_layoutstats_done(&hdr->task, hdr);
1996 	if (test_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags)) {
1997 		ff_layout_send_layouterror(hdr->lseg);
1998 		ff_layout_reset_write(hdr, true);
1999 	} else if (test_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags))
2000 		ff_layout_reset_write(hdr, false);
2001 	pnfs_generic_rw_release(data);
2002 }
2003 
2004 static void ff_layout_commit_record_layoutstats_start(struct rpc_task *task,
2005 		struct nfs_commit_data *cdata)
2006 {
2007 	u32 idx, dss_id;
2008 
2009 	if (test_and_set_bit(NFS_IOHDR_STAT, &cdata->flags))
2010 		return;
2011 
2012 	idx = calc_mirror_idx_from_commit(cdata->lseg, cdata->ds_commit_index);
2013 	dss_id = calc_dss_id_from_commit(cdata->lseg, cdata->ds_commit_index);
2014 	nfs4_ff_layout_stat_io_start_write(cdata->inode,
2015 			FF_LAYOUT_COMP(cdata->lseg, idx),
2016 			dss_id,
2017 			0, task->tk_start);
2018 }
2019 
2020 static void ff_layout_commit_record_layoutstats_done(struct rpc_task *task,
2021 		struct nfs_commit_data *cdata)
2022 {
2023 	struct nfs_page *req;
2024 	__u64 count = 0;
2025 	u32 idx, dss_id;
2026 
2027 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &cdata->flags))
2028 		return;
2029 
2030 	if (task->tk_status == 0) {
2031 		list_for_each_entry(req, &cdata->pages, wb_list)
2032 			count += req->wb_bytes;
2033 	}
2034 
2035 	idx = calc_mirror_idx_from_commit(cdata->lseg, cdata->ds_commit_index);
2036 	dss_id = calc_dss_id_from_commit(cdata->lseg, cdata->ds_commit_index);
2037 	nfs4_ff_layout_stat_io_end_write(task,
2038 			FF_LAYOUT_COMP(cdata->lseg, idx),
2039 			dss_id,
2040 			count, count, NFS_FILE_SYNC);
2041 	set_bit(NFS_LSEG_LAYOUTRETURN, &cdata->lseg->pls_flags);
2042 }
2043 
2044 static int ff_layout_commit_prepare_common(struct rpc_task *task,
2045 					   struct nfs_commit_data *cdata)
2046 {
2047 	if (!pnfs_is_valid_lseg(cdata->lseg)) {
2048 		rpc_exit(task, -EAGAIN);
2049 		return -EAGAIN;
2050 	}
2051 
2052 	ff_layout_commit_record_layoutstats_start(task, cdata);
2053 	return 0;
2054 }
2055 
2056 static void ff_layout_commit_prepare_v3(struct rpc_task *task, void *data)
2057 {
2058 	if (ff_layout_commit_prepare_common(task, data))
2059 		return;
2060 
2061 	rpc_call_start(task);
2062 }
2063 
2064 static void ff_layout_commit_prepare_v4(struct rpc_task *task, void *data)
2065 {
2066 	struct nfs_commit_data *wdata = data;
2067 
2068 	if (nfs4_setup_sequence(wdata->ds_clp,
2069 				&wdata->args.seq_args,
2070 				&wdata->res.seq_res,
2071 				task))
2072 		return;
2073 	ff_layout_commit_prepare_common(task, data);
2074 }
2075 
2076 static void ff_layout_commit_done(struct rpc_task *task, void *data)
2077 {
2078 	pnfs_generic_write_commit_done(task, data);
2079 }
2080 
2081 static void ff_layout_commit_count_stats(struct rpc_task *task, void *data)
2082 {
2083 	struct nfs_commit_data *cdata = data;
2084 
2085 	ff_layout_commit_record_layoutstats_done(task, cdata);
2086 	rpc_count_iostats_metrics(task,
2087 	    &NFS_CLIENT(cdata->inode)->cl_metrics[NFSPROC4_CLNT_COMMIT]);
2088 }
2089 
2090 static void ff_layout_commit_release(void *data)
2091 {
2092 	struct nfs_commit_data *cdata = data;
2093 
2094 	ff_layout_commit_record_layoutstats_done(&cdata->task, cdata);
2095 	pnfs_generic_commit_release(data);
2096 }
2097 
2098 static const struct rpc_call_ops ff_layout_read_call_ops_v3 = {
2099 	.rpc_call_prepare = ff_layout_read_prepare_v3,
2100 	.rpc_call_done = ff_layout_read_call_done,
2101 	.rpc_count_stats = ff_layout_read_count_stats,
2102 	.rpc_release = ff_layout_read_release,
2103 };
2104 
2105 static const struct rpc_call_ops ff_layout_read_call_ops_v4 = {
2106 	.rpc_call_prepare = ff_layout_read_prepare_v4,
2107 	.rpc_call_done = ff_layout_read_call_done,
2108 	.rpc_count_stats = ff_layout_read_count_stats,
2109 	.rpc_release = ff_layout_read_release,
2110 };
2111 
2112 static const struct rpc_call_ops ff_layout_write_call_ops_v3 = {
2113 	.rpc_call_prepare = ff_layout_write_prepare_v3,
2114 	.rpc_call_done = ff_layout_write_call_done,
2115 	.rpc_count_stats = ff_layout_write_count_stats,
2116 	.rpc_release = ff_layout_write_release,
2117 };
2118 
2119 static const struct rpc_call_ops ff_layout_write_call_ops_v4 = {
2120 	.rpc_call_prepare = ff_layout_write_prepare_v4,
2121 	.rpc_call_done = ff_layout_write_call_done,
2122 	.rpc_count_stats = ff_layout_write_count_stats,
2123 	.rpc_release = ff_layout_write_release,
2124 };
2125 
2126 static const struct rpc_call_ops ff_layout_commit_call_ops_v3 = {
2127 	.rpc_call_prepare = ff_layout_commit_prepare_v3,
2128 	.rpc_call_done = ff_layout_commit_done,
2129 	.rpc_count_stats = ff_layout_commit_count_stats,
2130 	.rpc_release = ff_layout_commit_release,
2131 };
2132 
2133 static const struct rpc_call_ops ff_layout_commit_call_ops_v4 = {
2134 	.rpc_call_prepare = ff_layout_commit_prepare_v4,
2135 	.rpc_call_done = ff_layout_commit_done,
2136 	.rpc_count_stats = ff_layout_commit_count_stats,
2137 	.rpc_release = ff_layout_commit_release,
2138 };
2139 
2140 static enum pnfs_try_status
2141 ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
2142 {
2143 	struct pnfs_layout_segment *lseg = hdr->lseg;
2144 	struct nfs4_pnfs_ds *ds;
2145 	struct rpc_clnt *ds_clnt;
2146 	struct nfsd_file *localio;
2147 	struct nfs4_ff_layout_mirror *mirror;
2148 	const struct cred *ds_cred;
2149 	loff_t offset = hdr->args.offset;
2150 	u32 idx = hdr->pgio_mirror_idx;
2151 	int vers;
2152 	struct nfs_fh *fh;
2153 	u32 dss_id;
2154 	bool ds_fatal_error = false;
2155 
2156 	dprintk("--> %s ino %llu pgbase %u req %zu@%llu\n",
2157 		__func__, hdr->inode->i_ino,
2158 		hdr->args.pgbase, (size_t)hdr->args.count, offset);
2159 
2160 	mirror = FF_LAYOUT_COMP(lseg, idx);
2161 	dss_id = nfs4_ff_layout_calc_dss_id(
2162 		FF_LAYOUT_LSEG(lseg)->stripe_unit,
2163 		mirror->dss_count,
2164 		offset);
2165 	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, dss_id, false);
2166 	if (IS_ERR(ds)) {
2167 		ds_fatal_error = nfs_error_is_fatal(PTR_ERR(ds));
2168 		goto out_failed;
2169 	}
2170 
2171 	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,
2172 						   hdr->inode, dss_id);
2173 	if (IS_ERR(ds_clnt))
2174 		goto out_failed;
2175 
2176 	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, hdr->cred, dss_id);
2177 	if (!ds_cred)
2178 		goto out_failed;
2179 
2180 	vers = nfs4_ff_layout_ds_version(mirror, dss_id);
2181 
2182 	dprintk("%s USE DS: %s cl_count %d vers %d\n", __func__,
2183 		ds->ds_remotestr, refcount_read(&ds->ds_clp->cl_count), vers);
2184 
2185 	hdr->pgio_done_cb = ff_layout_read_done_cb;
2186 	refcount_inc(&ds->ds_clp->cl_count);
2187 	hdr->ds_clp = ds->ds_clp;
2188 	fh = nfs4_ff_layout_select_ds_fh(mirror, dss_id);
2189 	if (fh)
2190 		hdr->args.fh = fh;
2191 
2192 	nfs4_ff_layout_select_ds_stateid(mirror, dss_id, &hdr->args.stateid);
2193 
2194 	/*
2195 	 * Note that if we ever decide to split across DSes,
2196 	 * then we may need to handle dense-like offsets.
2197 	 */
2198 	hdr->args.offset = offset;
2199 	hdr->mds_offset = offset;
2200 
2201 	/* Start IO accounting for local read */
2202 	localio = ff_local_open_fh(lseg, idx, dss_id, ds->ds_clp, ds_cred, fh,
2203 				FMODE_READ);
2204 	if (localio) {
2205 		hdr->task.tk_start = ktime_get();
2206 		ff_layout_read_record_layoutstats_start(&hdr->task, hdr);
2207 	}
2208 
2209 	/* Perform an asynchronous read to ds */
2210 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
2211 			  vers == 3 ? &ff_layout_read_call_ops_v3 :
2212 				      &ff_layout_read_call_ops_v4,
2213 			  0, RPC_TASK_SOFTCONN, localio);
2214 	put_cred(ds_cred);
2215 	return PNFS_ATTEMPTED;
2216 
2217 out_failed:
2218 	if (ff_layout_avoid_mds_available_ds(lseg) && !ds_fatal_error)
2219 		return PNFS_TRY_AGAIN;
2220 	if (ff_layout_no_fallback_to_mds(lseg)) {
2221 		/*
2222 		 * FF_FLAGS_NO_IO_THRU_MDS: force fresh LAYOUTGET,
2223 		 * never fall through to MDS I/O.
2224 		 */
2225 		pnfs_error_mark_layout_for_return(hdr->inode, lseg);
2226 		return PNFS_TRY_AGAIN;
2227 	}
2228 	trace_pnfs_mds_fallback_read_pagelist(hdr->inode,
2229 			hdr->args.offset, hdr->args.count,
2230 			IOMODE_READ, NFS_I(hdr->inode)->layout, lseg);
2231 	return PNFS_NOT_ATTEMPTED;
2232 }
2233 
2234 /* Perform async writes. */
2235 static enum pnfs_try_status
2236 ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
2237 {
2238 	struct pnfs_layout_segment *lseg = hdr->lseg;
2239 	struct nfs4_pnfs_ds *ds;
2240 	struct rpc_clnt *ds_clnt;
2241 	struct nfsd_file *localio;
2242 	struct nfs4_ff_layout_mirror *mirror;
2243 	const struct cred *ds_cred;
2244 	loff_t offset = hdr->args.offset;
2245 	int vers;
2246 	struct nfs_fh *fh;
2247 	u32 idx = hdr->pgio_mirror_idx;
2248 	u32 dss_id;
2249 	bool ds_fatal_error = false;
2250 
2251 	mirror = FF_LAYOUT_COMP(lseg, idx);
2252 	dss_id = nfs4_ff_layout_calc_dss_id(
2253 		FF_LAYOUT_LSEG(lseg)->stripe_unit,
2254 		mirror->dss_count,
2255 		offset);
2256 	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, dss_id, true);
2257 	if (IS_ERR(ds)) {
2258 		ds_fatal_error = nfs_error_is_fatal(PTR_ERR(ds));
2259 		goto out_failed;
2260 	}
2261 
2262 	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,
2263 						   hdr->inode, dss_id);
2264 	if (IS_ERR(ds_clnt))
2265 		goto out_failed;
2266 
2267 	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, hdr->cred, dss_id);
2268 	if (!ds_cred)
2269 		goto out_failed;
2270 
2271 	vers = nfs4_ff_layout_ds_version(mirror, dss_id);
2272 
2273 	dprintk("%s ino %llu sync %d req %zu@%llu DS: %s cl_count %d vers %d\n",
2274 		__func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
2275 		offset, ds->ds_remotestr, refcount_read(&ds->ds_clp->cl_count),
2276 		vers);
2277 
2278 	hdr->pgio_done_cb = ff_layout_write_done_cb;
2279 	refcount_inc(&ds->ds_clp->cl_count);
2280 	hdr->ds_clp = ds->ds_clp;
2281 	hdr->ds_commit_idx = calc_commit_idx(lseg, idx, dss_id);
2282 	fh = nfs4_ff_layout_select_ds_fh(mirror, dss_id);
2283 	if (fh)
2284 		hdr->args.fh = fh;
2285 
2286 	nfs4_ff_layout_select_ds_stateid(mirror, dss_id, &hdr->args.stateid);
2287 
2288 	/*
2289 	 * Note that if we ever decide to split across DSes,
2290 	 * then we may need to handle dense-like offsets.
2291 	 */
2292 	hdr->args.offset = offset;
2293 
2294 	/* Start IO accounting for local write */
2295 	localio = ff_local_open_fh(lseg, idx, dss_id, ds->ds_clp, ds_cred, fh,
2296 				   FMODE_READ|FMODE_WRITE);
2297 	if (localio) {
2298 		hdr->task.tk_start = ktime_get();
2299 		ff_layout_write_record_layoutstats_start(&hdr->task, hdr);
2300 	}
2301 
2302 	/* Perform an asynchronous write */
2303 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
2304 			  vers == 3 ? &ff_layout_write_call_ops_v3 :
2305 				      &ff_layout_write_call_ops_v4,
2306 			  sync, RPC_TASK_SOFTCONN, localio);
2307 	put_cred(ds_cred);
2308 	return PNFS_ATTEMPTED;
2309 
2310 out_failed:
2311 	if (ff_layout_avoid_mds_available_ds(lseg) && !ds_fatal_error)
2312 		return PNFS_TRY_AGAIN;
2313 	if (ff_layout_no_fallback_to_mds(lseg)) {
2314 		/*
2315 		 * FF_FLAGS_NO_IO_THRU_MDS: force fresh LAYOUTGET,
2316 		 * never fall through to MDS I/O.
2317 		 */
2318 		pnfs_error_mark_layout_for_return(hdr->inode, lseg);
2319 		return PNFS_TRY_AGAIN;
2320 	}
2321 	trace_pnfs_mds_fallback_write_pagelist(hdr->inode,
2322 			hdr->args.offset, hdr->args.count,
2323 			IOMODE_RW, NFS_I(hdr->inode)->layout, lseg);
2324 	return PNFS_NOT_ATTEMPTED;
2325 }
2326 
2327 static struct nfs_fh *
2328 select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i, u32 dss_id)
2329 {
2330 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
2331 
2332 	/* FIXME: Assume that there is only one NFS version available
2333 	 * for the DS.
2334 	 */
2335 	return &flseg->mirror_array[i]->dss[dss_id].fh_versions[0];
2336 }
2337 
2338 static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
2339 {
2340 	struct pnfs_layout_segment *lseg = data->lseg;
2341 	struct nfs4_pnfs_ds *ds;
2342 	struct rpc_clnt *ds_clnt;
2343 	struct nfsd_file *localio;
2344 	struct nfs4_ff_layout_mirror *mirror;
2345 	const struct cred *ds_cred;
2346 	u32 idx, dss_id;
2347 	int vers, ret;
2348 	struct nfs_fh *fh;
2349 
2350 	if (!lseg || !(pnfs_is_valid_lseg(lseg) ||
2351 	    test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags)))
2352 		goto out_err;
2353 
2354 	idx = calc_mirror_idx_from_commit(lseg, data->ds_commit_index);
2355 	mirror = FF_LAYOUT_COMP(lseg, idx);
2356 	dss_id = calc_dss_id_from_commit(lseg, data->ds_commit_index);
2357 	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, dss_id, true);
2358 	if (IS_ERR(ds))
2359 		goto out_err;
2360 
2361 	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,
2362 						   data->inode, dss_id);
2363 	if (IS_ERR(ds_clnt))
2364 		goto out_err;
2365 
2366 	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, data->cred, dss_id);
2367 	if (!ds_cred)
2368 		goto out_err;
2369 
2370 	vers = nfs4_ff_layout_ds_version(mirror, dss_id);
2371 
2372 	dprintk("%s ino %llu, how %d cl_count %d vers %d\n", __func__,
2373 		data->inode->i_ino, how, refcount_read(&ds->ds_clp->cl_count),
2374 		vers);
2375 	data->commit_done_cb = ff_layout_commit_done_cb;
2376 	data->cred = ds_cred;
2377 	refcount_inc(&ds->ds_clp->cl_count);
2378 	data->ds_clp = ds->ds_clp;
2379 	fh = select_ds_fh_from_commit(lseg, idx, dss_id);
2380 	if (fh)
2381 		data->args.fh = fh;
2382 
2383 	/* Start IO accounting for local commit */
2384 	localio = ff_local_open_fh(lseg, idx, dss_id, ds->ds_clp, ds_cred, fh,
2385 				   FMODE_READ|FMODE_WRITE);
2386 	if (localio) {
2387 		data->task.tk_start = ktime_get();
2388 		ff_layout_commit_record_layoutstats_start(&data->task, data);
2389 	}
2390 
2391 	ret = nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
2392 				   vers == 3 ? &ff_layout_commit_call_ops_v3 :
2393 					       &ff_layout_commit_call_ops_v4,
2394 				   how, RPC_TASK_SOFTCONN, localio);
2395 	put_cred(ds_cred);
2396 	return ret;
2397 out_err:
2398 	pnfs_generic_prepare_to_resend_writes(data);
2399 	pnfs_generic_commit_release(data);
2400 	return -EAGAIN;
2401 }
2402 
2403 static int
2404 ff_layout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
2405 			   int how, struct nfs_commit_info *cinfo)
2406 {
2407 	return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
2408 					    ff_layout_initiate_commit);
2409 }
2410 
2411 static bool ff_layout_match_rw(const struct rpc_task *task,
2412 			       const struct nfs_pgio_header *hdr,
2413 			       const struct pnfs_layout_segment *lseg)
2414 {
2415 	return hdr->lseg == lseg;
2416 }
2417 
2418 static bool ff_layout_match_commit(const struct rpc_task *task,
2419 				   const struct nfs_commit_data *cdata,
2420 				   const struct pnfs_layout_segment *lseg)
2421 {
2422 	return cdata->lseg == lseg;
2423 }
2424 
2425 static bool ff_layout_match_io(const struct rpc_task *task, const void *data)
2426 {
2427 	const struct rpc_call_ops *ops = task->tk_ops;
2428 
2429 	if (ops == &ff_layout_read_call_ops_v3 ||
2430 	    ops == &ff_layout_read_call_ops_v4 ||
2431 	    ops == &ff_layout_write_call_ops_v3 ||
2432 	    ops == &ff_layout_write_call_ops_v4)
2433 		return ff_layout_match_rw(task, task->tk_calldata, data);
2434 	if (ops == &ff_layout_commit_call_ops_v3 ||
2435 	    ops == &ff_layout_commit_call_ops_v4)
2436 		return ff_layout_match_commit(task, task->tk_calldata, data);
2437 	return false;
2438 }
2439 
2440 static void ff_layout_cancel_io(struct pnfs_layout_segment *lseg)
2441 {
2442 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
2443 	struct nfs4_ff_layout_mirror *mirror;
2444 	struct nfs4_ff_layout_ds *mirror_ds;
2445 	struct nfs4_pnfs_ds *ds;
2446 	struct nfs_client *ds_clp;
2447 	struct rpc_clnt *clnt;
2448 	u32 idx, dss_id;
2449 
2450 	for (idx = 0; idx < flseg->mirror_array_cnt; idx++) {
2451 		mirror = flseg->mirror_array[idx];
2452 		for (dss_id = 0; dss_id < mirror->dss_count; dss_id++) {
2453 			mirror_ds = mirror->dss[dss_id].mirror_ds;
2454 			if (IS_ERR_OR_NULL(mirror_ds))
2455 				continue;
2456 			ds = mirror->dss[dss_id].mirror_ds->ds;
2457 			if (!ds)
2458 				continue;
2459 			ds_clp = ds->ds_clp;
2460 			if (!ds_clp)
2461 				continue;
2462 			clnt = ds_clp->cl_rpcclient;
2463 			if (!clnt)
2464 				continue;
2465 			if (!rpc_cancel_tasks(clnt, -EAGAIN,
2466 					      ff_layout_match_io, lseg))
2467 				continue;
2468 			rpc_clnt_disconnect(clnt);
2469 		}
2470 	}
2471 }
2472 
2473 static struct pnfs_ds_commit_info *
2474 ff_layout_get_ds_info(struct inode *inode)
2475 {
2476 	struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
2477 
2478 	if (layout == NULL)
2479 		return NULL;
2480 
2481 	return &FF_LAYOUT_FROM_HDR(layout)->commit_info;
2482 }
2483 
2484 static void
2485 ff_layout_setup_ds_info(struct pnfs_ds_commit_info *fl_cinfo,
2486 		struct pnfs_layout_segment *lseg)
2487 {
2488 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
2489 	struct inode *inode = lseg->pls_layout->plh_inode;
2490 	struct pnfs_commit_array *array, *new;
2491 	u32 size = flseg->mirror_array_cnt * flseg->mirror_array[0]->dss_count;
2492 
2493 	new = pnfs_alloc_commit_array(size,
2494 				      nfs_io_gfp_mask());
2495 	if (new) {
2496 		spin_lock(&inode->i_lock);
2497 		array = pnfs_add_commit_array(fl_cinfo, new, lseg);
2498 		spin_unlock(&inode->i_lock);
2499 		if (array != new)
2500 			pnfs_free_commit_array(new);
2501 	}
2502 }
2503 
2504 static void
2505 ff_layout_release_ds_info(struct pnfs_ds_commit_info *fl_cinfo,
2506 		struct inode *inode)
2507 {
2508 	spin_lock(&inode->i_lock);
2509 	pnfs_generic_ds_cinfo_destroy(fl_cinfo);
2510 	spin_unlock(&inode->i_lock);
2511 }
2512 
2513 static void
2514 ff_layout_free_deviceid_node(struct nfs4_deviceid_node *d)
2515 {
2516 	nfs4_ff_layout_free_deviceid(container_of(d, struct nfs4_ff_layout_ds,
2517 						  id_node));
2518 }
2519 
2520 static int ff_layout_encode_ioerr(struct xdr_stream *xdr,
2521 				  const struct nfs4_layoutreturn_args *args,
2522 				  const struct nfs4_flexfile_layoutreturn_args *ff_args)
2523 {
2524 	__be32 *start;
2525 
2526 	start = xdr_reserve_space(xdr, 4);
2527 	if (unlikely(!start))
2528 		return -E2BIG;
2529 
2530 	*start = cpu_to_be32(ff_args->num_errors);
2531 	/* This assume we always return _ALL_ layouts */
2532 	return ff_layout_encode_ds_ioerr(xdr, &ff_args->errors);
2533 }
2534 
2535 static void
2536 ff_layout_encode_ff_iostat_head(struct xdr_stream *xdr,
2537 			    const nfs4_stateid *stateid,
2538 			    const struct nfs42_layoutstat_devinfo *devinfo)
2539 {
2540 	__be32 *p;
2541 
2542 	p = xdr_reserve_space(xdr, 8 + 8);
2543 	p = xdr_encode_hyper(p, devinfo->offset);
2544 	p = xdr_encode_hyper(p, devinfo->length);
2545 	encode_opaque_fixed(xdr, stateid->data, NFS4_STATEID_SIZE);
2546 	p = xdr_reserve_space(xdr, 4*8);
2547 	p = xdr_encode_hyper(p, devinfo->read_count);
2548 	p = xdr_encode_hyper(p, devinfo->read_bytes);
2549 	p = xdr_encode_hyper(p, devinfo->write_count);
2550 	p = xdr_encode_hyper(p, devinfo->write_bytes);
2551 	encode_opaque_fixed(xdr, devinfo->dev_id.data, NFS4_DEVICEID4_SIZE);
2552 }
2553 
2554 static void
2555 ff_layout_encode_ff_iostat(struct xdr_stream *xdr,
2556 			    const nfs4_stateid *stateid,
2557 			    const struct nfs42_layoutstat_devinfo *devinfo)
2558 {
2559 	ff_layout_encode_ff_iostat_head(xdr, stateid, devinfo);
2560 	ff_layout_encode_ff_layoutupdate(xdr, devinfo,
2561 			devinfo->ld_private.data);
2562 }
2563 
2564 /* report nothing for now */
2565 static void ff_layout_encode_iostats_array(struct xdr_stream *xdr,
2566 		const struct nfs4_layoutreturn_args *args,
2567 		struct nfs4_flexfile_layoutreturn_args *ff_args)
2568 {
2569 	__be32 *p;
2570 	int i;
2571 
2572 	p = xdr_reserve_space(xdr, 4);
2573 	*p = cpu_to_be32(ff_args->num_dev);
2574 	for (i = 0; i < ff_args->num_dev; i++)
2575 		ff_layout_encode_ff_iostat(xdr,
2576 				&args->layout->plh_stateid,
2577 				&ff_args->devinfo[i]);
2578 }
2579 
2580 static void
2581 ff_layout_free_iostats_array(struct nfs42_layoutstat_devinfo *devinfo,
2582 		unsigned int num_entries)
2583 {
2584 	unsigned int i;
2585 
2586 	for (i = 0; i < num_entries; i++) {
2587 		if (!devinfo[i].ld_private.ops)
2588 			continue;
2589 		if (!devinfo[i].ld_private.ops->free)
2590 			continue;
2591 		devinfo[i].ld_private.ops->free(&devinfo[i].ld_private);
2592 	}
2593 }
2594 
2595 static struct nfs4_deviceid_node *
2596 ff_layout_alloc_deviceid_node(struct nfs_server *server,
2597 			      struct pnfs_device *pdev, gfp_t gfp_flags)
2598 {
2599 	struct nfs4_ff_layout_ds *dsaddr;
2600 
2601 	dsaddr = nfs4_ff_alloc_deviceid_node(server, pdev, gfp_flags);
2602 	if (!dsaddr)
2603 		return NULL;
2604 	return &dsaddr->id_node;
2605 }
2606 
2607 static void
2608 ff_layout_encode_layoutreturn(struct xdr_stream *xdr,
2609 		const void *voidargs,
2610 		const struct nfs4_xdr_opaque_data *ff_opaque)
2611 {
2612 	const struct nfs4_layoutreturn_args *args = voidargs;
2613 	struct nfs4_flexfile_layoutreturn_args *ff_args = ff_opaque->data;
2614 	struct xdr_buf tmp_buf = {
2615 		.head = {
2616 			[0] = {
2617 				.iov_base = page_address(ff_args->pages[0]),
2618 			},
2619 		},
2620 		.buflen = PAGE_SIZE,
2621 	};
2622 	struct xdr_stream tmp_xdr;
2623 	__be32 *start;
2624 
2625 	dprintk("%s: Begin\n", __func__);
2626 
2627 	xdr_init_encode(&tmp_xdr, &tmp_buf, NULL, NULL);
2628 
2629 	ff_layout_encode_ioerr(&tmp_xdr, args, ff_args);
2630 	ff_layout_encode_iostats_array(&tmp_xdr, args, ff_args);
2631 
2632 	start = xdr_reserve_space(xdr, 4);
2633 	*start = cpu_to_be32(tmp_buf.len);
2634 	xdr_write_pages(xdr, ff_args->pages, 0, tmp_buf.len);
2635 
2636 	dprintk("%s: Return\n", __func__);
2637 }
2638 
2639 static void
2640 ff_layout_free_layoutreturn(struct nfs4_xdr_opaque_data *args)
2641 {
2642 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2643 
2644 	if (!args->data)
2645 		return;
2646 	ff_args = args->data;
2647 	args->data = NULL;
2648 
2649 	ff_layout_free_ds_ioerr(&ff_args->errors);
2650 	ff_layout_free_iostats_array(ff_args->devinfo, ff_args->num_dev);
2651 
2652 	put_page(ff_args->pages[0]);
2653 	kfree(ff_args);
2654 }
2655 
2656 static const struct nfs4_xdr_opaque_ops layoutreturn_ops = {
2657 	.encode = ff_layout_encode_layoutreturn,
2658 	.free = ff_layout_free_layoutreturn,
2659 };
2660 
2661 static int
2662 ff_layout_prepare_layoutreturn(struct nfs4_layoutreturn_args *args)
2663 {
2664 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2665 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(args->layout);
2666 
2667 	ff_args = kmalloc_obj(*ff_args, nfs_io_gfp_mask());
2668 	if (!ff_args)
2669 		goto out_nomem;
2670 	ff_args->pages[0] = alloc_page(nfs_io_gfp_mask());
2671 	if (!ff_args->pages[0])
2672 		goto out_nomem_free;
2673 
2674 	INIT_LIST_HEAD(&ff_args->errors);
2675 	ff_args->num_errors = ff_layout_fetch_ds_ioerr(args->layout,
2676 			&args->range, &ff_args->errors,
2677 			FF_LAYOUTRETURN_MAXERR);
2678 
2679 	spin_lock(&args->inode->i_lock);
2680 	ff_args->num_dev = ff_layout_mirror_prepare_stats(
2681 		&ff_layout->generic_hdr, &ff_args->devinfo[0],
2682 		ARRAY_SIZE(ff_args->devinfo), NFS4_FF_OP_LAYOUTRETURN);
2683 	spin_unlock(&args->inode->i_lock);
2684 
2685 	args->ld_private->ops = &layoutreturn_ops;
2686 	args->ld_private->data = ff_args;
2687 	return 0;
2688 out_nomem_free:
2689 	kfree(ff_args);
2690 out_nomem:
2691 	return -ENOMEM;
2692 }
2693 
2694 #ifdef CONFIG_NFS_V4_2
2695 void
2696 ff_layout_send_layouterror(struct pnfs_layout_segment *lseg)
2697 {
2698 	struct pnfs_layout_hdr *lo = lseg->pls_layout;
2699 	struct nfs42_layout_error *errors;
2700 	LIST_HEAD(head);
2701 
2702 	if (!nfs_server_capable(lo->plh_inode, NFS_CAP_LAYOUTERROR))
2703 		return;
2704 	ff_layout_fetch_ds_ioerr(lo, &lseg->pls_range, &head, -1);
2705 	if (list_empty(&head))
2706 		return;
2707 
2708 	errors = kmalloc_objs(*errors, NFS42_LAYOUTERROR_MAX, nfs_io_gfp_mask());
2709 	if (errors != NULL) {
2710 		const struct nfs4_ff_layout_ds_err *pos;
2711 		size_t n = 0;
2712 
2713 		list_for_each_entry(pos, &head, list) {
2714 			errors[n].offset = pos->offset;
2715 			errors[n].length = pos->length;
2716 			nfs4_stateid_copy(&errors[n].stateid, &pos->stateid);
2717 			errors[n].errors[0].dev_id = pos->deviceid;
2718 			errors[n].errors[0].status = pos->status;
2719 			errors[n].errors[0].opnum = pos->opnum;
2720 			n++;
2721 			if (!list_is_last(&pos->list, &head) &&
2722 			    n < NFS42_LAYOUTERROR_MAX)
2723 				continue;
2724 			if (nfs42_proc_layouterror(lseg, errors, n) < 0)
2725 				break;
2726 			n = 0;
2727 		}
2728 		kfree(errors);
2729 	}
2730 	ff_layout_free_ds_ioerr(&head);
2731 }
2732 #else
2733 void
2734 ff_layout_send_layouterror(struct pnfs_layout_segment *lseg)
2735 {
2736 }
2737 #endif
2738 
2739 static int
2740 ff_layout_ntop4(const struct sockaddr *sap, char *buf, const size_t buflen)
2741 {
2742 	const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
2743 
2744 	return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
2745 }
2746 
2747 static size_t
2748 ff_layout_ntop6_noscopeid(const struct sockaddr *sap, char *buf,
2749 			  const int buflen)
2750 {
2751 	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
2752 	const struct in6_addr *addr = &sin6->sin6_addr;
2753 
2754 	/*
2755 	 * RFC 4291, Section 2.2.2
2756 	 *
2757 	 * Shorthanded ANY address
2758 	 */
2759 	if (ipv6_addr_any(addr))
2760 		return snprintf(buf, buflen, "::");
2761 
2762 	/*
2763 	 * RFC 4291, Section 2.2.2
2764 	 *
2765 	 * Shorthanded loopback address
2766 	 */
2767 	if (ipv6_addr_loopback(addr))
2768 		return snprintf(buf, buflen, "::1");
2769 
2770 	/*
2771 	 * RFC 4291, Section 2.2.3
2772 	 *
2773 	 * Special presentation address format for mapped v4
2774 	 * addresses.
2775 	 */
2776 	if (ipv6_addr_v4mapped(addr))
2777 		return snprintf(buf, buflen, "::ffff:%pI4",
2778 					&addr->s6_addr32[3]);
2779 
2780 	/*
2781 	 * RFC 4291, Section 2.2.1
2782 	 */
2783 	return snprintf(buf, buflen, "%pI6c", addr);
2784 }
2785 
2786 /* Derived from rpc_sockaddr2uaddr */
2787 static void
2788 ff_layout_encode_netaddr(struct xdr_stream *xdr, struct nfs4_pnfs_ds_addr *da)
2789 {
2790 	struct sockaddr *sap = (struct sockaddr *)&da->da_addr;
2791 	char portbuf[RPCBIND_MAXUADDRPLEN];
2792 	char addrbuf[RPCBIND_MAXUADDRLEN];
2793 	unsigned short port;
2794 	int len, netid_len;
2795 	__be32 *p;
2796 
2797 	switch (sap->sa_family) {
2798 	case AF_INET:
2799 		if (ff_layout_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
2800 			return;
2801 		port = ntohs(((struct sockaddr_in *)sap)->sin_port);
2802 		break;
2803 	case AF_INET6:
2804 		if (ff_layout_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
2805 			return;
2806 		port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
2807 		break;
2808 	default:
2809 		WARN_ON_ONCE(1);
2810 		return;
2811 	}
2812 
2813 	snprintf(portbuf, sizeof(portbuf), ".%u.%u", port >> 8, port & 0xff);
2814 	len = strlcat(addrbuf, portbuf, sizeof(addrbuf));
2815 
2816 	netid_len = strlen(da->da_netid);
2817 	p = xdr_reserve_space(xdr, 4 + netid_len);
2818 	xdr_encode_opaque(p, da->da_netid, netid_len);
2819 
2820 	p = xdr_reserve_space(xdr, 4 + len);
2821 	xdr_encode_opaque(p, addrbuf, len);
2822 }
2823 
2824 static void
2825 ff_layout_encode_nfstime(struct xdr_stream *xdr,
2826 			 ktime_t t)
2827 {
2828 	struct timespec64 ts;
2829 	__be32 *p;
2830 
2831 	p = xdr_reserve_space(xdr, 12);
2832 	ts = ktime_to_timespec64(t);
2833 	p = xdr_encode_hyper(p, ts.tv_sec);
2834 	*p++ = cpu_to_be32(ts.tv_nsec);
2835 }
2836 
2837 static void
2838 ff_layout_encode_io_latency(struct xdr_stream *xdr,
2839 			    struct nfs4_ff_io_stat *stat)
2840 {
2841 	__be32 *p;
2842 
2843 	p = xdr_reserve_space(xdr, 5 * 8);
2844 	p = xdr_encode_hyper(p, stat->ops_requested);
2845 	p = xdr_encode_hyper(p, stat->bytes_requested);
2846 	p = xdr_encode_hyper(p, stat->ops_completed);
2847 	p = xdr_encode_hyper(p, stat->bytes_completed);
2848 	p = xdr_encode_hyper(p, stat->bytes_not_delivered);
2849 	ff_layout_encode_nfstime(xdr, stat->total_busy_time);
2850 	ff_layout_encode_nfstime(xdr, stat->aggregate_completion_time);
2851 }
2852 
2853 static void
2854 ff_layout_encode_ff_layoutupdate(struct xdr_stream *xdr,
2855 			      const struct nfs42_layoutstat_devinfo *devinfo,
2856 			      struct nfs4_ff_layout_ds_stripe *dss_info)
2857 {
2858 	struct nfs4_pnfs_ds_addr *da;
2859 	struct nfs4_pnfs_ds *ds = dss_info->mirror_ds->ds;
2860 	struct nfs_fh *fh = &dss_info->fh_versions[0];
2861 	__be32 *p;
2862 
2863 	da = list_first_entry(&ds->ds_addrs, struct nfs4_pnfs_ds_addr, da_node);
2864 	dprintk("%s: DS %s: encoding address %s\n",
2865 		__func__, ds->ds_remotestr, da->da_remotestr);
2866 	/* netaddr4 */
2867 	ff_layout_encode_netaddr(xdr, da);
2868 	/* nfs_fh4 */
2869 	p = xdr_reserve_space(xdr, 4 + fh->size);
2870 	xdr_encode_opaque(p, fh->data, fh->size);
2871 	/* ff_io_latency4 read */
2872 	spin_lock(&dss_info->mirror->lock);
2873 	ff_layout_encode_io_latency(xdr,
2874 				    &dss_info->read_stat.io_stat);
2875 	/* ff_io_latency4 write */
2876 	ff_layout_encode_io_latency(xdr,
2877 				    &dss_info->write_stat.io_stat);
2878 	spin_unlock(&dss_info->mirror->lock);
2879 	/* nfstime4 */
2880 	ff_layout_encode_nfstime(xdr,
2881 				 ktime_sub(ktime_get(),
2882 					   dss_info->start_time));
2883 	/* bool */
2884 	p = xdr_reserve_space(xdr, 4);
2885 	*p = cpu_to_be32(false);
2886 }
2887 
2888 static void
2889 ff_layout_encode_layoutstats(struct xdr_stream *xdr, const void *args,
2890 			     const struct nfs4_xdr_opaque_data *opaque)
2891 {
2892 	struct nfs42_layoutstat_devinfo *devinfo = container_of(opaque,
2893 			struct nfs42_layoutstat_devinfo, ld_private);
2894 	__be32 *start;
2895 
2896 	/* layoutupdate length */
2897 	start = xdr_reserve_space(xdr, 4);
2898 	ff_layout_encode_ff_layoutupdate(xdr, devinfo, opaque->data);
2899 
2900 	*start = cpu_to_be32((xdr->p - start - 1) * 4);
2901 }
2902 
2903 static void
2904 ff_layout_free_layoutstats(struct nfs4_xdr_opaque_data *opaque)
2905 {
2906 	struct nfs4_ff_layout_ds_stripe *dss_info = opaque->data;
2907 	struct nfs4_ff_layout_mirror *mirror = dss_info->mirror;
2908 
2909 	ff_layout_put_mirror(mirror);
2910 }
2911 
2912 static const struct nfs4_xdr_opaque_ops layoutstat_ops = {
2913 	.encode = ff_layout_encode_layoutstats,
2914 	.free	= ff_layout_free_layoutstats,
2915 };
2916 
2917 static int
2918 ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
2919 			       struct nfs42_layoutstat_devinfo *devinfo,
2920 			       int dev_limit, enum nfs4_ff_op_type type)
2921 {
2922 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
2923 	struct nfs4_ff_layout_mirror *mirror;
2924 	struct nfs4_ff_layout_ds_stripe *dss_info;
2925 	struct nfs4_deviceid_node *dev;
2926 	int i = 0, dss_id;
2927 
2928 	list_for_each_entry(mirror, &ff_layout->mirrors, mirrors) {
2929 		for (dss_id = 0; dss_id < mirror->dss_count; ++dss_id) {
2930 			dss_info = &mirror->dss[dss_id];
2931 			if (i >= dev_limit)
2932 				break;
2933 			if (IS_ERR_OR_NULL(dss_info->mirror_ds))
2934 				continue;
2935 			if (!test_and_clear_bit(NFS4_FF_MIRROR_STAT_AVAIL,
2936 						&mirror->flags) &&
2937 			    type != NFS4_FF_OP_LAYOUTRETURN)
2938 				continue;
2939 			/* mirror refcount put in cleanup_layoutstats */
2940 			if (!refcount_inc_not_zero(&mirror->ref))
2941 				continue;
2942 			dev = &dss_info->mirror_ds->id_node;
2943 			memcpy(&devinfo->dev_id,
2944 			       &dev->deviceid,
2945 			       NFS4_DEVICEID4_SIZE);
2946 			devinfo->offset = 0;
2947 			devinfo->length = NFS4_MAX_UINT64;
2948 			spin_lock(&mirror->lock);
2949 			devinfo->read_count =
2950 			    dss_info->read_stat.io_stat.ops_completed;
2951 			devinfo->read_bytes =
2952 			    dss_info->read_stat.io_stat.bytes_completed;
2953 			devinfo->write_count =
2954 			    dss_info->write_stat.io_stat.ops_completed;
2955 			devinfo->write_bytes =
2956 			    dss_info->write_stat.io_stat.bytes_completed;
2957 			spin_unlock(&mirror->lock);
2958 			devinfo->layout_type = LAYOUT_FLEX_FILES;
2959 			devinfo->ld_private.ops = &layoutstat_ops;
2960 			devinfo->ld_private.data = &mirror->dss[dss_id];
2961 
2962 			devinfo++;
2963 			i++;
2964 		}
2965 	}
2966 	return i;
2967 }
2968 
2969 static int ff_layout_prepare_layoutstats(struct nfs42_layoutstat_args *args)
2970 {
2971 	struct pnfs_layout_hdr *lo;
2972 	struct nfs4_flexfile_layout *ff_layout;
2973 	const int dev_count = PNFS_LAYOUTSTATS_MAXDEV;
2974 
2975 	/* For now, send at most PNFS_LAYOUTSTATS_MAXDEV statistics */
2976 	args->devinfo = kmalloc_objs(*args->devinfo, dev_count,
2977 				     nfs_io_gfp_mask());
2978 	if (!args->devinfo)
2979 		return -ENOMEM;
2980 
2981 	spin_lock(&args->inode->i_lock);
2982 	lo = NFS_I(args->inode)->layout;
2983 	if (lo && pnfs_layout_is_valid(lo)) {
2984 		ff_layout = FF_LAYOUT_FROM_HDR(lo);
2985 		args->num_dev = ff_layout_mirror_prepare_stats(
2986 			&ff_layout->generic_hdr, &args->devinfo[0], dev_count,
2987 			NFS4_FF_OP_LAYOUTSTATS);
2988 	} else
2989 		args->num_dev = 0;
2990 	spin_unlock(&args->inode->i_lock);
2991 	if (!args->num_dev) {
2992 		kfree(args->devinfo);
2993 		args->devinfo = NULL;
2994 		return -ENOENT;
2995 	}
2996 
2997 	return 0;
2998 }
2999 
3000 static int
3001 ff_layout_set_layoutdriver(struct nfs_server *server,
3002 		const struct nfs_fh *dummy)
3003 {
3004 #if IS_ENABLED(CONFIG_NFS_V4_2)
3005 	server->caps |= NFS_CAP_LAYOUTSTATS | NFS_CAP_REBOOT_LAYOUTRETURN;
3006 #endif
3007 	return 0;
3008 }
3009 
3010 static const struct pnfs_commit_ops ff_layout_commit_ops = {
3011 	.setup_ds_info		= ff_layout_setup_ds_info,
3012 	.release_ds_info	= ff_layout_release_ds_info,
3013 	.mark_request_commit	= pnfs_layout_mark_request_commit,
3014 	.clear_request_commit	= pnfs_generic_clear_request_commit,
3015 	.scan_commit_lists	= pnfs_generic_scan_commit_lists,
3016 	.recover_commit_reqs	= pnfs_generic_recover_commit_reqs,
3017 	.commit_pagelist	= ff_layout_commit_pagelist,
3018 };
3019 
3020 static struct pnfs_layoutdriver_type flexfilelayout_type = {
3021 	.id			= LAYOUT_FLEX_FILES,
3022 	.name			= "LAYOUT_FLEX_FILES",
3023 	.owner			= THIS_MODULE,
3024 	.flags			= PNFS_LAYOUTGET_ON_OPEN,
3025 	.max_layoutget_response	= 4096, /* 1 page or so... */
3026 	.set_layoutdriver	= ff_layout_set_layoutdriver,
3027 	.alloc_layout_hdr	= ff_layout_alloc_layout_hdr,
3028 	.free_layout_hdr	= ff_layout_free_layout_hdr,
3029 	.alloc_lseg		= ff_layout_alloc_lseg,
3030 	.free_lseg		= ff_layout_free_lseg,
3031 	.add_lseg		= ff_layout_add_lseg,
3032 	.pg_read_ops		= &ff_layout_pg_read_ops,
3033 	.pg_write_ops		= &ff_layout_pg_write_ops,
3034 	.get_ds_info		= ff_layout_get_ds_info,
3035 	.free_deviceid_node	= ff_layout_free_deviceid_node,
3036 	.read_pagelist		= ff_layout_read_pagelist,
3037 	.write_pagelist		= ff_layout_write_pagelist,
3038 	.alloc_deviceid_node    = ff_layout_alloc_deviceid_node,
3039 	.prepare_layoutreturn   = ff_layout_prepare_layoutreturn,
3040 	.sync			= pnfs_nfs_generic_sync,
3041 	.prepare_layoutstats	= ff_layout_prepare_layoutstats,
3042 	.cancel_io		= ff_layout_cancel_io,
3043 };
3044 
3045 static int __init nfs4flexfilelayout_init(void)
3046 {
3047 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Registering...\n",
3048 	       __func__);
3049 	return pnfs_register_layoutdriver(&flexfilelayout_type);
3050 }
3051 
3052 static void __exit nfs4flexfilelayout_exit(void)
3053 {
3054 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Unregistering...\n",
3055 	       __func__);
3056 	pnfs_unregister_layoutdriver(&flexfilelayout_type);
3057 }
3058 
3059 MODULE_ALIAS("nfs-layouttype4-4");
3060 
3061 MODULE_LICENSE("GPL");
3062 MODULE_DESCRIPTION("The NFSv4 flexfile layout driver");
3063 
3064 module_init(nfs4flexfilelayout_init);
3065 module_exit(nfs4flexfilelayout_exit);
3066 
3067 module_param(io_maxretrans, ushort, 0644);
3068 MODULE_PARM_DESC(io_maxretrans, "The  number of times the NFSv4.1 client "
3069 			"retries an I/O request before returning an error. ");
3070