xref: /linux/fs/nfs/flexfilelayout/flexfilelayout.c (revision 69050f8d6d075dc01af7a5f2f550a8067510366f)
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 
555 			dss_info->fh_versions =
556 			    kzalloc_objs(struct nfs_fh, fh_count, gfp_flags);
557 			if (dss_info->fh_versions == NULL) {
558 				rc = -ENOMEM;
559 				goto out_err_free;
560 			}
561 
562 			for (j = 0; j < fh_count; j++) {
563 				rc = decode_nfs_fh(&stream,
564 						   &dss_info->fh_versions[j]);
565 				if (rc)
566 					goto out_err_free;
567 			}
568 
569 			dss_info->fh_versions_cnt = fh_count;
570 
571 			/* user */
572 			rc = decode_name(&stream, &id);
573 			if (rc)
574 				goto out_err_free;
575 
576 			uid = make_kuid(&init_user_ns, id);
577 
578 			/* group */
579 			rc = decode_name(&stream, &id);
580 			if (rc)
581 				goto out_err_free;
582 
583 			gid = make_kgid(&init_user_ns, id);
584 
585 			if (gfp_flags & __GFP_FS)
586 				kcred = prepare_kernel_cred(&init_task);
587 			else {
588 				unsigned int nofs_flags = memalloc_nofs_save();
589 
590 				kcred = prepare_kernel_cred(&init_task);
591 				memalloc_nofs_restore(nofs_flags);
592 			}
593 			rc = -ENOMEM;
594 			if (!kcred)
595 				goto out_err_free;
596 			kcred->fsuid = uid;
597 			kcred->fsgid = gid;
598 			cred = RCU_INITIALIZER(kcred);
599 
600 			if (lgr->range.iomode == IOMODE_READ)
601 				rcu_assign_pointer(dss_info->ro_cred, cred);
602 			else
603 				rcu_assign_pointer(dss_info->rw_cred, cred);
604 		}
605 
606 		mirror = ff_layout_add_mirror(lh, fls->mirror_array[i]);
607 		if (mirror != fls->mirror_array[i]) {
608 			for (dss_id = 0; dss_id < dss_count; dss_id++) {
609 				dss_info = &fls->mirror_array[i]->dss[dss_id];
610 				/* swap cred ptrs so free_mirror will clean up old */
611 				if (lgr->range.iomode == IOMODE_READ) {
612 					cred = xchg(&mirror->dss[dss_id].ro_cred,
613 						    dss_info->ro_cred);
614 					rcu_assign_pointer(dss_info->ro_cred, cred);
615 				} else {
616 					cred = xchg(&mirror->dss[dss_id].rw_cred,
617 						    dss_info->rw_cred);
618 					rcu_assign_pointer(dss_info->rw_cred, cred);
619 				}
620 			}
621 			ff_layout_free_mirror(fls->mirror_array[i]);
622 			fls->mirror_array[i] = mirror;
623 		}
624 
625 		dprintk("%s: iomode %s uid %u gid %u\n", __func__,
626 			lgr->range.iomode == IOMODE_READ ? "READ" : "RW",
627 			from_kuid(&init_user_ns, uid),
628 			from_kgid(&init_user_ns, gid));
629 	}
630 
631 	p = xdr_inline_decode(&stream, 4);
632 	if (!p)
633 		goto out_sort_mirrors;
634 	fls->flags = be32_to_cpup(p);
635 
636 	p = xdr_inline_decode(&stream, 4);
637 	if (!p)
638 		goto out_sort_mirrors;
639 	for (i=0; i < fls->mirror_array_cnt; i++)
640 		fls->mirror_array[i]->report_interval = be32_to_cpup(p);
641 
642 out_sort_mirrors:
643 	ff_layout_sort_mirrors(fls);
644 	ret = &fls->generic_hdr;
645 	dprintk("<-- %s (success)\n", __func__);
646 out_free_page:
647 	folio_put(scratch);
648 	return ret;
649 out_err_free:
650 	_ff_layout_free_lseg(fls);
651 	ret = ERR_PTR(rc);
652 	dprintk("<-- %s (%d)\n", __func__, rc);
653 	goto out_free_page;
654 }
655 
656 static void
657 ff_layout_free_lseg(struct pnfs_layout_segment *lseg)
658 {
659 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
660 
661 	dprintk("--> %s\n", __func__);
662 
663 	if (lseg->pls_range.iomode == IOMODE_RW) {
664 		struct nfs4_flexfile_layout *ffl;
665 		struct inode *inode;
666 
667 		ffl = FF_LAYOUT_FROM_HDR(lseg->pls_layout);
668 		inode = ffl->generic_hdr.plh_inode;
669 		spin_lock(&inode->i_lock);
670 		pnfs_generic_ds_cinfo_release_lseg(&ffl->commit_info, lseg);
671 		spin_unlock(&inode->i_lock);
672 	}
673 	_ff_layout_free_lseg(fls);
674 }
675 
676 static u32 calc_commit_idx(struct pnfs_layout_segment *lseg,
677 			   u32 mirror_idx, u32 dss_id)
678 {
679 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
680 
681 	return (mirror_idx * flseg->mirror_array[0]->dss_count) + dss_id;
682 }
683 
684 static u32 calc_mirror_idx_from_commit(struct pnfs_layout_segment *lseg,
685 				       u32 commit_index)
686 {
687 	return commit_index / FF_LAYOUT_LSEG(lseg)->mirror_array[0]->dss_count;
688 }
689 
690 static u32 calc_dss_id_from_commit(struct pnfs_layout_segment *lseg,
691 				   u32 commit_index)
692 {
693 	return commit_index % FF_LAYOUT_LSEG(lseg)->mirror_array[0]->dss_count;
694 }
695 
696 static void
697 nfs4_ff_start_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
698 {
699 	/* first IO request? */
700 	if (atomic_inc_return(&timer->n_ops) == 1) {
701 		timer->start_time = now;
702 	}
703 }
704 
705 static ktime_t
706 nfs4_ff_end_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
707 {
708 	ktime_t start;
709 
710 	if (atomic_dec_return(&timer->n_ops) < 0)
711 		WARN_ON_ONCE(1);
712 
713 	start = timer->start_time;
714 	timer->start_time = now;
715 	return ktime_sub(now, start);
716 }
717 
718 static bool
719 nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_mirror *mirror,
720 			    u32 dss_id,
721 			    struct nfs4_ff_layoutstat *layoutstat,
722 			    ktime_t now)
723 {
724 	s64 report_interval = FF_LAYOUTSTATS_REPORT_INTERVAL;
725 	struct nfs4_flexfile_layout *ffl = FF_LAYOUT_FROM_HDR(mirror->layout);
726 
727 	nfs4_ff_start_busy_timer(&layoutstat->busy_timer, now);
728 	if (!mirror->dss[dss_id].start_time)
729 		mirror->dss[dss_id].start_time = now;
730 	if (mirror->report_interval != 0)
731 		report_interval = (s64)mirror->report_interval * 1000LL;
732 	else if (layoutstats_timer != 0)
733 		report_interval = (s64)layoutstats_timer * 1000LL;
734 	if (ktime_to_ms(ktime_sub(now, ffl->last_report_time)) >=
735 			report_interval) {
736 		ffl->last_report_time = now;
737 		return true;
738 	}
739 
740 	return false;
741 }
742 
743 static void
744 nfs4_ff_layout_stat_io_update_requested(struct nfs4_ff_layoutstat *layoutstat,
745 		__u64 requested)
746 {
747 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
748 
749 	iostat->ops_requested++;
750 	iostat->bytes_requested += requested;
751 }
752 
753 static void
754 nfs4_ff_layout_stat_io_update_completed(struct nfs4_ff_layoutstat *layoutstat,
755 		__u64 requested,
756 		__u64 completed,
757 		ktime_t time_completed,
758 		ktime_t time_started)
759 {
760 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
761 	ktime_t completion_time = ktime_sub(time_completed, time_started);
762 	ktime_t timer;
763 
764 	iostat->ops_completed++;
765 	iostat->bytes_completed += completed;
766 	iostat->bytes_not_delivered += requested - completed;
767 
768 	timer = nfs4_ff_end_busy_timer(&layoutstat->busy_timer, time_completed);
769 	iostat->total_busy_time =
770 			ktime_add(iostat->total_busy_time, timer);
771 	iostat->aggregate_completion_time =
772 			ktime_add(iostat->aggregate_completion_time,
773 					completion_time);
774 }
775 
776 static void
777 nfs4_ff_layout_stat_io_start_read(struct inode *inode,
778 		struct nfs4_ff_layout_mirror *mirror,
779 		u32 dss_id,
780 		__u64 requested, ktime_t now)
781 {
782 	bool report;
783 
784 	spin_lock(&mirror->lock);
785 	report = nfs4_ff_layoutstat_start_io(
786 		mirror, dss_id, &mirror->dss[dss_id].read_stat, now);
787 	nfs4_ff_layout_stat_io_update_requested(
788 		&mirror->dss[dss_id].read_stat, requested);
789 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
790 	spin_unlock(&mirror->lock);
791 
792 	if (report)
793 		pnfs_report_layoutstat(inode, nfs_io_gfp_mask());
794 }
795 
796 static void
797 nfs4_ff_layout_stat_io_end_read(struct rpc_task *task,
798 		struct nfs4_ff_layout_mirror *mirror,
799 		u32 dss_id,
800 		__u64 requested,
801 		__u64 completed)
802 {
803 	spin_lock(&mirror->lock);
804 	nfs4_ff_layout_stat_io_update_completed(&mirror->dss[dss_id].read_stat,
805 			requested, completed,
806 			ktime_get(), task->tk_start);
807 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
808 	spin_unlock(&mirror->lock);
809 }
810 
811 static void
812 nfs4_ff_layout_stat_io_start_write(struct inode *inode,
813 		struct nfs4_ff_layout_mirror *mirror,
814 		u32 dss_id,
815 		__u64 requested, ktime_t now)
816 {
817 	bool report;
818 
819 	spin_lock(&mirror->lock);
820 	report = nfs4_ff_layoutstat_start_io(
821 		mirror,
822 		dss_id,
823 		&mirror->dss[dss_id].write_stat,
824 		now);
825 	nfs4_ff_layout_stat_io_update_requested(
826 		&mirror->dss[dss_id].write_stat,
827 		requested);
828 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
829 	spin_unlock(&mirror->lock);
830 
831 	if (report)
832 		pnfs_report_layoutstat(inode, nfs_io_gfp_mask());
833 }
834 
835 static void
836 nfs4_ff_layout_stat_io_end_write(struct rpc_task *task,
837 		struct nfs4_ff_layout_mirror *mirror,
838 		u32 dss_id,
839 		__u64 requested,
840 		__u64 completed,
841 		enum nfs3_stable_how committed)
842 {
843 	if (committed == NFS_UNSTABLE)
844 		requested = completed = 0;
845 
846 	spin_lock(&mirror->lock);
847 	nfs4_ff_layout_stat_io_update_completed(&mirror->dss[dss_id].write_stat,
848 			requested, completed, ktime_get(), task->tk_start);
849 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
850 	spin_unlock(&mirror->lock);
851 }
852 
853 static void
854 ff_layout_mark_ds_unreachable(struct pnfs_layout_segment *lseg, u32 idx, u32 dss_id)
855 {
856 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx, dss_id);
857 
858 	if (devid)
859 		nfs4_mark_deviceid_unavailable(devid);
860 }
861 
862 static void
863 ff_layout_mark_ds_reachable(struct pnfs_layout_segment *lseg, u32 idx, u32 dss_id)
864 {
865 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx, dss_id);
866 
867 	if (devid)
868 		nfs4_mark_deviceid_available(devid);
869 }
870 
871 static struct nfs4_pnfs_ds *
872 ff_layout_choose_ds_for_read(struct pnfs_layout_segment *lseg,
873 			     u32 start_idx, u32 *best_idx,
874 			     u32 offset, u32 *dss_id,
875 			     bool check_device)
876 {
877 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
878 	struct nfs4_ff_layout_mirror *mirror;
879 	struct nfs4_pnfs_ds *ds = ERR_PTR(-EAGAIN);
880 	u32 idx;
881 
882 	/* mirrors are initially sorted by efficiency */
883 	for (idx = start_idx; idx < fls->mirror_array_cnt; idx++) {
884 		mirror = FF_LAYOUT_COMP(lseg, idx);
885 		*dss_id = nfs4_ff_layout_calc_dss_id(
886 			fls->stripe_unit,
887 			fls->mirror_array[idx]->dss_count,
888 			offset);
889 		ds = nfs4_ff_layout_prepare_ds(lseg, mirror, *dss_id, false);
890 		if (IS_ERR(ds))
891 			continue;
892 
893 		if (check_device &&
894 		    nfs4_test_deviceid_unavailable(&mirror->dss[*dss_id].mirror_ds->id_node)) {
895 			// reinitialize the error state in case if this is the last iteration
896 			ds = ERR_PTR(-EINVAL);
897 			continue;
898 		}
899 
900 		*best_idx = idx;
901 		break;
902 	}
903 
904 	return ds;
905 }
906 
907 static struct nfs4_pnfs_ds *
908 ff_layout_choose_any_ds_for_read(struct pnfs_layout_segment *lseg,
909 				 u32 start_idx, u32 *best_idx,
910 				 u32 offset, u32 *dss_id)
911 {
912 	return ff_layout_choose_ds_for_read(lseg, start_idx, best_idx,
913 					    offset, dss_id, false);
914 }
915 
916 static struct nfs4_pnfs_ds *
917 ff_layout_choose_valid_ds_for_read(struct pnfs_layout_segment *lseg,
918 				   u32 start_idx, u32 *best_idx,
919 				   u32 offset, u32 *dss_id)
920 {
921 	return ff_layout_choose_ds_for_read(lseg, start_idx, best_idx,
922 					    offset, dss_id, true);
923 }
924 
925 static struct nfs4_pnfs_ds *
926 ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg,
927 				  u32 start_idx, u32 *best_idx,
928 				  u32 offset, u32 *dss_id)
929 {
930 	struct nfs4_pnfs_ds *ds;
931 
932 	ds = ff_layout_choose_valid_ds_for_read(lseg, start_idx, best_idx,
933 						offset, dss_id);
934 	if (!IS_ERR(ds))
935 		return ds;
936 	return ff_layout_choose_any_ds_for_read(lseg, start_idx, best_idx,
937 						offset, dss_id);
938 }
939 
940 static struct nfs4_pnfs_ds *
941 ff_layout_get_ds_for_read(struct nfs_pageio_descriptor *pgio,
942 			  u32 *best_idx,
943 			  u32 offset,
944 			  u32 *dss_id)
945 {
946 	struct pnfs_layout_segment *lseg = pgio->pg_lseg;
947 	struct nfs4_pnfs_ds *ds;
948 
949 	ds = ff_layout_choose_best_ds_for_read(lseg, pgio->pg_mirror_idx,
950 					       best_idx, offset, dss_id);
951 	if (!IS_ERR(ds) || !pgio->pg_mirror_idx)
952 		return ds;
953 	return ff_layout_choose_best_ds_for_read(lseg, 0, best_idx,
954 						 offset, dss_id);
955 }
956 
957 static void
958 ff_layout_pg_get_read(struct nfs_pageio_descriptor *pgio,
959 		      struct nfs_page *req,
960 		      bool strict_iomode)
961 {
962 	pnfs_put_lseg(pgio->pg_lseg);
963 	pgio->pg_lseg =
964 		pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
965 				   req_offset(req), req->wb_bytes, IOMODE_READ,
966 				   strict_iomode, nfs_io_gfp_mask());
967 	if (IS_ERR(pgio->pg_lseg)) {
968 		pgio->pg_error = PTR_ERR(pgio->pg_lseg);
969 		pgio->pg_lseg = NULL;
970 	}
971 }
972 
973 static bool
974 ff_layout_lseg_is_striped(const struct nfs4_ff_layout_segment *fls)
975 {
976 	return fls->mirror_array[0]->dss_count > 1;
977 }
978 
979 /*
980  * ff_layout_pg_test(). Called by nfs_can_coalesce_requests()
981  *
982  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
983  * of bytes (maximum @req->wb_bytes) that can be coalesced.
984  */
985 static size_t
986 ff_layout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
987 		  struct nfs_page *req)
988 {
989 	unsigned int size;
990 	u64 p_stripe, r_stripe;
991 	u32 stripe_offset;
992 	u64 segment_offset = pgio->pg_lseg->pls_range.offset;
993 	u32 stripe_unit = FF_LAYOUT_LSEG(pgio->pg_lseg)->stripe_unit;
994 
995 	/* calls nfs_generic_pg_test */
996 	size = pnfs_generic_pg_test(pgio, prev, req);
997 	if (!size)
998 		return 0;
999 	else if (!ff_layout_lseg_is_striped(FF_LAYOUT_LSEG(pgio->pg_lseg)))
1000 		return size;
1001 
1002 	/* see if req and prev are in the same stripe */
1003 	if (prev) {
1004 		p_stripe = (u64)req_offset(prev) - segment_offset;
1005 		r_stripe = (u64)req_offset(req) - segment_offset;
1006 		do_div(p_stripe, stripe_unit);
1007 		do_div(r_stripe, stripe_unit);
1008 
1009 		if (p_stripe != r_stripe)
1010 			return 0;
1011 	}
1012 
1013 	/* calculate remaining bytes in the current stripe */
1014 	div_u64_rem((u64)req_offset(req) - segment_offset,
1015 			stripe_unit,
1016 			&stripe_offset);
1017 	WARN_ON_ONCE(stripe_offset > stripe_unit);
1018 	if (stripe_offset >= stripe_unit)
1019 		return 0;
1020 	return min(stripe_unit - (unsigned int)stripe_offset, size);
1021 }
1022 
1023 static void
1024 ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
1025 			struct nfs_page *req)
1026 {
1027 	struct nfs_pgio_mirror *pgm;
1028 	struct nfs4_ff_layout_mirror *mirror;
1029 	struct nfs4_pnfs_ds *ds;
1030 	u32 ds_idx, dss_id;
1031 
1032 	if (NFS_SERVER(pgio->pg_inode)->flags &
1033 			(NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR))
1034 		pgio->pg_maxretrans = io_maxretrans;
1035 retry:
1036 	pnfs_generic_pg_check_layout(pgio, req);
1037 	/* Use full layout for now */
1038 	if (!pgio->pg_lseg) {
1039 		ff_layout_pg_get_read(pgio, req, false);
1040 		if (!pgio->pg_lseg)
1041 			goto out_nolseg;
1042 	}
1043 	if (ff_layout_avoid_read_on_rw(pgio->pg_lseg)) {
1044 		ff_layout_pg_get_read(pgio, req, true);
1045 		if (!pgio->pg_lseg)
1046 			goto out_nolseg;
1047 	}
1048 	/* Reset wb_nio, since getting layout segment was successful */
1049 	req->wb_nio = 0;
1050 
1051 	ds = ff_layout_get_ds_for_read(pgio, &ds_idx,
1052 				       req_offset(req), &dss_id);
1053 	if (IS_ERR(ds)) {
1054 		if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
1055 			goto out_mds;
1056 		pnfs_generic_pg_cleanup(pgio);
1057 		/* Sleep for 1 second before retrying */
1058 		ssleep(1);
1059 		goto retry;
1060 	}
1061 
1062 	mirror = FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx);
1063 	pgm = &pgio->pg_mirrors[0];
1064 	pgm->pg_bsize = mirror->dss[dss_id].mirror_ds->ds_versions[0].rsize;
1065 
1066 	pgio->pg_mirror_idx = ds_idx;
1067 	return;
1068 out_nolseg:
1069 	if (pgio->pg_error < 0) {
1070 		if (pgio->pg_error != -EAGAIN)
1071 			return;
1072 		/* Retry getting layout segment if lower layer returned -EAGAIN */
1073 		if (pgio->pg_maxretrans && req->wb_nio++ > pgio->pg_maxretrans) {
1074 			if (NFS_SERVER(pgio->pg_inode)->flags & NFS_MOUNT_SOFTERR)
1075 				pgio->pg_error = -ETIMEDOUT;
1076 			else
1077 				pgio->pg_error = -EIO;
1078 			return;
1079 		}
1080 		pgio->pg_error = 0;
1081 		/* Sleep for 1 second before retrying */
1082 		ssleep(1);
1083 		goto retry;
1084 	}
1085 out_mds:
1086 	trace_pnfs_mds_fallback_pg_init_read(pgio->pg_inode,
1087 			0, NFS4_MAX_UINT64, IOMODE_READ,
1088 			NFS_I(pgio->pg_inode)->layout,
1089 			pgio->pg_lseg);
1090 	pgio->pg_maxretrans = 0;
1091 	nfs_pageio_reset_read_mds(pgio);
1092 }
1093 
1094 static void
1095 ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
1096 			struct nfs_page *req)
1097 {
1098 	struct nfs4_ff_layout_mirror *mirror;
1099 	struct nfs_pgio_mirror *pgm;
1100 	struct nfs4_pnfs_ds *ds;
1101 	u32 i, dss_id;
1102 
1103 retry:
1104 	pnfs_generic_pg_check_layout(pgio, req);
1105 	if (!pgio->pg_lseg) {
1106 		pgio->pg_lseg =
1107 			pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
1108 					   req_offset(req), req->wb_bytes,
1109 					   IOMODE_RW, false, nfs_io_gfp_mask());
1110 		if (IS_ERR(pgio->pg_lseg)) {
1111 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
1112 			pgio->pg_lseg = NULL;
1113 			return;
1114 		}
1115 	}
1116 	/* If no lseg, fall back to write through mds */
1117 	if (pgio->pg_lseg == NULL)
1118 		goto out_mds;
1119 
1120 	/* Use a direct mapping of ds_idx to pgio mirror_idx */
1121 	if (pgio->pg_mirror_count != FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg))
1122 		goto out_eagain;
1123 
1124 	for (i = 0; i < pgio->pg_mirror_count; i++) {
1125 		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
1126 		dss_id = nfs4_ff_layout_calc_dss_id(
1127 			FF_LAYOUT_LSEG(pgio->pg_lseg)->stripe_unit,
1128 			mirror->dss_count,
1129 			req_offset(req));
1130 		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, mirror,
1131 					       dss_id, true);
1132 		if (IS_ERR(ds)) {
1133 			if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
1134 				goto out_mds;
1135 			pnfs_generic_pg_cleanup(pgio);
1136 			/* Sleep for 1 second before retrying */
1137 			ssleep(1);
1138 			goto retry;
1139 		}
1140 		pgm = &pgio->pg_mirrors[i];
1141 		pgm->pg_bsize = mirror->dss[dss_id].mirror_ds->ds_versions[0].wsize;
1142 	}
1143 
1144 	if (NFS_SERVER(pgio->pg_inode)->flags &
1145 			(NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR))
1146 		pgio->pg_maxretrans = io_maxretrans;
1147 	return;
1148 out_eagain:
1149 	pnfs_generic_pg_cleanup(pgio);
1150 	pgio->pg_error = -EAGAIN;
1151 	return;
1152 out_mds:
1153 	trace_pnfs_mds_fallback_pg_init_write(pgio->pg_inode,
1154 			0, NFS4_MAX_UINT64, IOMODE_RW,
1155 			NFS_I(pgio->pg_inode)->layout,
1156 			pgio->pg_lseg);
1157 	pgio->pg_maxretrans = 0;
1158 	nfs_pageio_reset_write_mds(pgio);
1159 	pgio->pg_error = -EAGAIN;
1160 }
1161 
1162 static unsigned int
1163 ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
1164 				    struct nfs_page *req)
1165 {
1166 	if (!pgio->pg_lseg) {
1167 		pgio->pg_lseg =
1168 			pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
1169 					   req_offset(req), req->wb_bytes,
1170 					   IOMODE_RW, false, nfs_io_gfp_mask());
1171 		if (IS_ERR(pgio->pg_lseg)) {
1172 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
1173 			pgio->pg_lseg = NULL;
1174 			goto out;
1175 		}
1176 	}
1177 	if (pgio->pg_lseg)
1178 		return FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg);
1179 
1180 	trace_pnfs_mds_fallback_pg_get_mirror_count(pgio->pg_inode,
1181 			0, NFS4_MAX_UINT64, IOMODE_RW,
1182 			NFS_I(pgio->pg_inode)->layout,
1183 			pgio->pg_lseg);
1184 	/* no lseg means that pnfs is not in use, so no mirroring here */
1185 	nfs_pageio_reset_write_mds(pgio);
1186 out:
1187 	return 1;
1188 }
1189 
1190 static u32
1191 ff_layout_pg_set_mirror_write(struct nfs_pageio_descriptor *desc, u32 idx)
1192 {
1193 	u32 old = desc->pg_mirror_idx;
1194 
1195 	desc->pg_mirror_idx = idx;
1196 	return old;
1197 }
1198 
1199 static struct nfs_pgio_mirror *
1200 ff_layout_pg_get_mirror_write(struct nfs_pageio_descriptor *desc, u32 idx)
1201 {
1202 	return &desc->pg_mirrors[idx];
1203 }
1204 
1205 static const struct nfs_pageio_ops ff_layout_pg_read_ops = {
1206 	.pg_init = ff_layout_pg_init_read,
1207 	.pg_test = ff_layout_pg_test,
1208 	.pg_doio = pnfs_generic_pg_readpages,
1209 	.pg_cleanup = pnfs_generic_pg_cleanup,
1210 };
1211 
1212 static const struct nfs_pageio_ops ff_layout_pg_write_ops = {
1213 	.pg_init = ff_layout_pg_init_write,
1214 	.pg_test = ff_layout_pg_test,
1215 	.pg_doio = pnfs_generic_pg_writepages,
1216 	.pg_get_mirror_count = ff_layout_pg_get_mirror_count_write,
1217 	.pg_cleanup = pnfs_generic_pg_cleanup,
1218 	.pg_get_mirror = ff_layout_pg_get_mirror_write,
1219 	.pg_set_mirror = ff_layout_pg_set_mirror_write,
1220 };
1221 
1222 static void ff_layout_reset_write(struct nfs_pgio_header *hdr, bool retry_pnfs)
1223 {
1224 	struct rpc_task *task = &hdr->task;
1225 
1226 	pnfs_layoutcommit_inode(hdr->inode, false);
1227 
1228 	if (retry_pnfs) {
1229 		dprintk("%s Reset task %5u for i/o through pNFS "
1230 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1231 			hdr->task.tk_pid,
1232 			hdr->inode->i_sb->s_id,
1233 			(unsigned long long)NFS_FILEID(hdr->inode),
1234 			hdr->args.count,
1235 			(unsigned long long)hdr->args.offset);
1236 
1237 		hdr->completion_ops->reschedule_io(hdr);
1238 		return;
1239 	}
1240 
1241 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1242 		dprintk("%s Reset task %5u for i/o through MDS "
1243 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1244 			hdr->task.tk_pid,
1245 			hdr->inode->i_sb->s_id,
1246 			(unsigned long long)NFS_FILEID(hdr->inode),
1247 			hdr->args.count,
1248 			(unsigned long long)hdr->args.offset);
1249 
1250 		trace_pnfs_mds_fallback_write_done(hdr->inode,
1251 				hdr->args.offset, hdr->args.count,
1252 				IOMODE_RW, NFS_I(hdr->inode)->layout,
1253 				hdr->lseg);
1254 		task->tk_status = pnfs_write_done_resend_to_mds(hdr);
1255 	}
1256 }
1257 
1258 static void ff_layout_resend_pnfs_read(struct nfs_pgio_header *hdr)
1259 {
1260 	u32 idx = hdr->pgio_mirror_idx + 1;
1261 	u32 new_idx = 0;
1262 	u32 dss_id = 0;
1263 	struct nfs4_pnfs_ds *ds;
1264 
1265 	ds = ff_layout_choose_any_ds_for_read(hdr->lseg, idx, &new_idx,
1266 					      hdr->args.offset, &dss_id);
1267 	if (IS_ERR(ds))
1268 		pnfs_error_mark_layout_for_return(hdr->inode, hdr->lseg);
1269 	else
1270 		ff_layout_send_layouterror(hdr->lseg);
1271 	pnfs_read_resend_pnfs(hdr, new_idx);
1272 }
1273 
1274 static void ff_layout_reset_read(struct nfs_pgio_header *hdr)
1275 {
1276 	struct rpc_task *task = &hdr->task;
1277 
1278 	pnfs_layoutcommit_inode(hdr->inode, false);
1279 	pnfs_error_mark_layout_for_return(hdr->inode, hdr->lseg);
1280 
1281 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1282 		dprintk("%s Reset task %5u for i/o through MDS "
1283 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1284 			hdr->task.tk_pid,
1285 			hdr->inode->i_sb->s_id,
1286 			(unsigned long long)NFS_FILEID(hdr->inode),
1287 			hdr->args.count,
1288 			(unsigned long long)hdr->args.offset);
1289 
1290 		trace_pnfs_mds_fallback_read_done(hdr->inode,
1291 				hdr->args.offset, hdr->args.count,
1292 				IOMODE_READ, NFS_I(hdr->inode)->layout,
1293 				hdr->lseg);
1294 		task->tk_status = pnfs_read_done_resend_to_mds(hdr);
1295 	}
1296 }
1297 
1298 static int ff_layout_async_handle_error_v4(struct rpc_task *task,
1299 					   u32 op_status,
1300 					   struct nfs4_state *state,
1301 					   struct nfs_client *clp,
1302 					   struct pnfs_layout_segment *lseg,
1303 					   u32 idx, u32 dss_id)
1304 {
1305 	struct pnfs_layout_hdr *lo = lseg->pls_layout;
1306 	struct inode *inode = lo->plh_inode;
1307 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx, dss_id);
1308 	struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
1309 
1310 	switch (op_status) {
1311 	case NFS4_OK:
1312 	case NFS4ERR_NXIO:
1313 		break;
1314 	case NFSERR_PERM:
1315 		if (!task->tk_xprt)
1316 			break;
1317 		xprt_force_disconnect(task->tk_xprt);
1318 		goto out_retry;
1319 	case NFS4ERR_BADSESSION:
1320 	case NFS4ERR_BADSLOT:
1321 	case NFS4ERR_BAD_HIGH_SLOT:
1322 	case NFS4ERR_DEADSESSION:
1323 	case NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
1324 	case NFS4ERR_SEQ_FALSE_RETRY:
1325 	case NFS4ERR_SEQ_MISORDERED:
1326 		dprintk("%s ERROR %d, Reset session. Exchangeid "
1327 			"flags 0x%x\n", __func__, task->tk_status,
1328 			clp->cl_exchange_flags);
1329 		nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
1330 		goto out_retry;
1331 	case NFS4ERR_DELAY:
1332 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1333 		fallthrough;
1334 	case NFS4ERR_GRACE:
1335 		rpc_delay(task, FF_LAYOUT_POLL_RETRY_MAX);
1336 		goto out_retry;
1337 	case NFS4ERR_RETRY_UNCACHED_REP:
1338 		goto out_retry;
1339 	/* Invalidate Layout errors */
1340 	case NFS4ERR_PNFS_NO_LAYOUT:
1341 	case NFS4ERR_STALE:
1342 	case NFS4ERR_BADHANDLE:
1343 	case NFS4ERR_ISDIR:
1344 	case NFS4ERR_FHEXPIRED:
1345 	case NFS4ERR_WRONG_TYPE:
1346 		dprintk("%s Invalid layout error %d\n", __func__,
1347 			task->tk_status);
1348 		/*
1349 		 * Destroy layout so new i/o will get a new layout.
1350 		 * Layout will not be destroyed until all current lseg
1351 		 * references are put. Mark layout as invalid to resend failed
1352 		 * i/o and all i/o waiting on the slot table to the MDS until
1353 		 * layout is destroyed and a new valid layout is obtained.
1354 		 */
1355 		pnfs_destroy_layout(NFS_I(inode));
1356 		rpc_wake_up(&tbl->slot_tbl_waitq);
1357 		goto reset;
1358 	default:
1359 		break;
1360 	}
1361 
1362 	switch (task->tk_status) {
1363 	/* RPC connection errors */
1364 	case -ENETDOWN:
1365 	case -ENETUNREACH:
1366 		if (test_bit(NFS_CS_NETUNREACH_FATAL, &clp->cl_flags))
1367 			return -NFS4ERR_FATAL_IOERROR;
1368 		fallthrough;
1369 	case -ECONNREFUSED:
1370 	case -EHOSTDOWN:
1371 	case -EHOSTUNREACH:
1372 	case -EIO:
1373 	case -ETIMEDOUT:
1374 	case -EPIPE:
1375 	case -EPROTO:
1376 	case -ENODEV:
1377 		dprintk("%s DS connection error %d\n", __func__,
1378 			task->tk_status);
1379 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1380 				&devid->deviceid);
1381 		rpc_wake_up(&tbl->slot_tbl_waitq);
1382 		break;
1383 	default:
1384 		break;
1385 	}
1386 
1387 	if (ff_layout_avoid_mds_available_ds(lseg))
1388 		return -NFS4ERR_RESET_TO_PNFS;
1389 reset:
1390 	dprintk("%s Retry through MDS. Error %d\n", __func__,
1391 		task->tk_status);
1392 	return -NFS4ERR_RESET_TO_MDS;
1393 
1394 out_retry:
1395 	task->tk_status = 0;
1396 	return -EAGAIN;
1397 }
1398 
1399 /* Retry all errors through either pNFS or MDS except for -EJUKEBOX */
1400 static int ff_layout_async_handle_error_v3(struct rpc_task *task,
1401 					   u32 op_status,
1402 					   struct nfs_client *clp,
1403 					   struct pnfs_layout_segment *lseg,
1404 					   u32 idx, u32 dss_id)
1405 {
1406 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx, dss_id);
1407 
1408 	switch (op_status) {
1409 	case NFS_OK:
1410 	case NFSERR_NXIO:
1411 		break;
1412 	case NFSERR_PERM:
1413 		if (!task->tk_xprt)
1414 			break;
1415 		xprt_force_disconnect(task->tk_xprt);
1416 		goto out_retry;
1417 	case NFSERR_ACCES:
1418 	case NFSERR_BADHANDLE:
1419 	case NFSERR_FBIG:
1420 	case NFSERR_IO:
1421 	case NFSERR_NOSPC:
1422 	case NFSERR_ROFS:
1423 	case NFSERR_STALE:
1424 		goto out_reset_to_pnfs;
1425 	case NFSERR_JUKEBOX:
1426 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1427 		goto out_retry;
1428 	default:
1429 		break;
1430 	}
1431 
1432 	switch (task->tk_status) {
1433 	/* File access problems. Don't mark the device as unavailable */
1434 	case -EACCES:
1435 	case -ESTALE:
1436 	case -EISDIR:
1437 	case -EBADHANDLE:
1438 	case -ELOOP:
1439 	case -ENOSPC:
1440 		break;
1441 	case -EJUKEBOX:
1442 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1443 		goto out_retry;
1444 	case -ENETDOWN:
1445 	case -ENETUNREACH:
1446 		if (test_bit(NFS_CS_NETUNREACH_FATAL, &clp->cl_flags))
1447 			return -NFS4ERR_FATAL_IOERROR;
1448 		fallthrough;
1449 	default:
1450 		dprintk("%s DS connection error %d\n", __func__,
1451 			task->tk_status);
1452 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1453 				&devid->deviceid);
1454 	}
1455 out_reset_to_pnfs:
1456 	/* FIXME: Need to prevent infinite looping here. */
1457 	return -NFS4ERR_RESET_TO_PNFS;
1458 out_retry:
1459 	task->tk_status = 0;
1460 	rpc_restart_call_prepare(task);
1461 	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
1462 	return -EAGAIN;
1463 }
1464 
1465 static int ff_layout_async_handle_error(struct rpc_task *task,
1466 					u32 op_status,
1467 					struct nfs4_state *state,
1468 					struct nfs_client *clp,
1469 					struct pnfs_layout_segment *lseg,
1470 					u32 idx, u32 dss_id)
1471 {
1472 	int vers = clp->cl_nfs_mod->rpc_vers->number;
1473 
1474 	if (task->tk_status >= 0) {
1475 		ff_layout_mark_ds_reachable(lseg, idx, dss_id);
1476 		return 0;
1477 	}
1478 
1479 	/* Handle the case of an invalid layout segment */
1480 	if (!pnfs_is_valid_lseg(lseg))
1481 		return -NFS4ERR_RESET_TO_PNFS;
1482 
1483 	switch (vers) {
1484 	case 3:
1485 		return ff_layout_async_handle_error_v3(task, op_status, clp,
1486 						       lseg, idx, dss_id);
1487 	case 4:
1488 		return ff_layout_async_handle_error_v4(task, op_status, state,
1489 						       clp, lseg, idx, dss_id);
1490 	default:
1491 		/* should never happen */
1492 		WARN_ON_ONCE(1);
1493 		return 0;
1494 	}
1495 }
1496 
1497 static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg,
1498 					u32 idx, u32 dss_id, u64 offset, u64 length,
1499 					u32 *op_status, int opnum, int error)
1500 {
1501 	struct nfs4_ff_layout_mirror *mirror;
1502 	u32 status = *op_status;
1503 	int err;
1504 
1505 	if (status == 0) {
1506 		switch (error) {
1507 		case -ETIMEDOUT:
1508 		case -EPFNOSUPPORT:
1509 		case -EPROTONOSUPPORT:
1510 		case -EOPNOTSUPP:
1511 		case -EINVAL:
1512 		case -ECONNREFUSED:
1513 		case -ECONNRESET:
1514 		case -EHOSTDOWN:
1515 		case -EHOSTUNREACH:
1516 		case -ENETDOWN:
1517 		case -ENETUNREACH:
1518 		case -EADDRINUSE:
1519 		case -ENOBUFS:
1520 		case -EPIPE:
1521 		case -EPERM:
1522 		case -EPROTO:
1523 		case -ENODEV:
1524 			*op_status = status = NFS4ERR_NXIO;
1525 			break;
1526 		case -EACCES:
1527 			*op_status = status = NFS4ERR_ACCESS;
1528 			break;
1529 		default:
1530 			return;
1531 		}
1532 	}
1533 
1534 	mirror = FF_LAYOUT_COMP(lseg, idx);
1535 	err = ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),
1536 				       mirror, dss_id, offset, length, status, opnum,
1537 				       nfs_io_gfp_mask());
1538 
1539 	switch (status) {
1540 	case NFS4ERR_DELAY:
1541 	case NFS4ERR_GRACE:
1542 	case NFS4ERR_PERM:
1543 		break;
1544 	case NFS4ERR_NXIO:
1545 		ff_layout_mark_ds_unreachable(lseg, idx, dss_id);
1546 		/*
1547 		 * Don't return the layout if this is a read and we still
1548 		 * have layouts to try
1549 		 */
1550 		if (opnum == OP_READ)
1551 			break;
1552 		fallthrough;
1553 	default:
1554 		pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode,
1555 						  lseg);
1556 	}
1557 
1558 	dprintk("%s: err %d op %d status %u\n", __func__, err, opnum, status);
1559 }
1560 
1561 /* NFS_PROTO call done callback routines */
1562 static int ff_layout_read_done_cb(struct rpc_task *task,
1563 				struct nfs_pgio_header *hdr)
1564 {
1565 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(hdr->lseg);
1566 	u32 dss_id = nfs4_ff_layout_calc_dss_id(
1567 		flseg->stripe_unit,
1568 		flseg->mirror_array[hdr->pgio_mirror_idx]->dss_count,
1569 		hdr->args.offset);
1570 	int err;
1571 
1572 	if (task->tk_status < 0) {
1573 		ff_layout_io_track_ds_error(hdr->lseg,
1574 					    hdr->pgio_mirror_idx, dss_id,
1575 					    hdr->args.offset, hdr->args.count,
1576 					    &hdr->res.op_status, OP_READ,
1577 					    task->tk_status);
1578 		trace_ff_layout_read_error(hdr, task->tk_status);
1579 	}
1580 
1581 	err = ff_layout_async_handle_error(task, hdr->res.op_status,
1582 					   hdr->args.context->state,
1583 					   hdr->ds_clp, hdr->lseg,
1584 					   hdr->pgio_mirror_idx,
1585 					   dss_id);
1586 
1587 	trace_nfs4_pnfs_read(hdr, err);
1588 	clear_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1589 	clear_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1590 	switch (err) {
1591 	case -NFS4ERR_RESET_TO_PNFS:
1592 		set_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1593 		return task->tk_status;
1594 	case -NFS4ERR_RESET_TO_MDS:
1595 		set_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1596 		return task->tk_status;
1597 	case -EAGAIN:
1598 		goto out_eagain;
1599 	case -NFS4ERR_FATAL_IOERROR:
1600 		task->tk_status = -EIO;
1601 		return 0;
1602 	}
1603 
1604 	return 0;
1605 out_eagain:
1606 	rpc_restart_call_prepare(task);
1607 	return -EAGAIN;
1608 }
1609 
1610 static bool
1611 ff_layout_need_layoutcommit(struct pnfs_layout_segment *lseg)
1612 {
1613 	return !(FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_LAYOUTCOMMIT);
1614 }
1615 
1616 /*
1617  * We reference the rpc_cred of the first WRITE that triggers the need for
1618  * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
1619  * rfc5661 is not clear about which credential should be used.
1620  *
1621  * Flexlayout client should treat DS replied FILE_SYNC as DATA_SYNC, so
1622  * to follow http://www.rfc-editor.org/errata_search.php?rfc=5661&eid=2751
1623  * we always send layoutcommit after DS writes.
1624  */
1625 static void
1626 ff_layout_set_layoutcommit(struct inode *inode,
1627 		struct pnfs_layout_segment *lseg,
1628 		loff_t end_offset)
1629 {
1630 	if (!ff_layout_need_layoutcommit(lseg))
1631 		return;
1632 
1633 	pnfs_set_layoutcommit(inode, lseg, end_offset);
1634 	dprintk("%s inode %lu pls_end_pos %llu\n", __func__, inode->i_ino,
1635 		(unsigned long long) NFS_I(inode)->layout->plh_lwb);
1636 }
1637 
1638 static void ff_layout_read_record_layoutstats_start(struct rpc_task *task,
1639 		struct nfs_pgio_header *hdr)
1640 {
1641 	struct nfs4_ff_layout_mirror *mirror;
1642 	u32 dss_id;
1643 
1644 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1645 		return;
1646 
1647 	mirror = FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx);
1648 	dss_id = nfs4_ff_layout_calc_dss_id(
1649 		FF_LAYOUT_LSEG(hdr->lseg)->stripe_unit,
1650 		mirror->dss_count,
1651 		hdr->args.offset);
1652 
1653 	nfs4_ff_layout_stat_io_start_read(
1654 		hdr->inode,
1655 		mirror,
1656 		dss_id,
1657 		hdr->args.count,
1658 		task->tk_start);
1659 }
1660 
1661 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
1662 		struct nfs_pgio_header *hdr)
1663 {
1664 	struct nfs4_ff_layout_mirror *mirror;
1665 	u32 dss_id;
1666 
1667 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1668 		return;
1669 
1670 	mirror = FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx);
1671 	dss_id = nfs4_ff_layout_calc_dss_id(
1672 		FF_LAYOUT_LSEG(hdr->lseg)->stripe_unit,
1673 		mirror->dss_count,
1674 		hdr->args.offset);
1675 
1676 	nfs4_ff_layout_stat_io_end_read(
1677 		task,
1678 		mirror,
1679 		dss_id,
1680 		hdr->args.count,
1681 		hdr->res.count);
1682 	set_bit(NFS_LSEG_LAYOUTRETURN, &hdr->lseg->pls_flags);
1683 }
1684 
1685 static int ff_layout_read_prepare_common(struct rpc_task *task,
1686 					 struct nfs_pgio_header *hdr)
1687 {
1688 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1689 		rpc_exit(task, -EIO);
1690 		return -EIO;
1691 	}
1692 
1693 	if (!pnfs_is_valid_lseg(hdr->lseg)) {
1694 		rpc_exit(task, -EAGAIN);
1695 		return -EAGAIN;
1696 	}
1697 
1698 	ff_layout_read_record_layoutstats_start(task, hdr);
1699 	return 0;
1700 }
1701 
1702 /*
1703  * Call ops for the async read/write cases
1704  * In the case of dense layouts, the offset needs to be reset to its
1705  * original value.
1706  */
1707 static void ff_layout_read_prepare_v3(struct rpc_task *task, void *data)
1708 {
1709 	struct nfs_pgio_header *hdr = data;
1710 
1711 	if (ff_layout_read_prepare_common(task, hdr))
1712 		return;
1713 
1714 	rpc_call_start(task);
1715 }
1716 
1717 static void ff_layout_read_prepare_v4(struct rpc_task *task, void *data)
1718 {
1719 	struct nfs_pgio_header *hdr = data;
1720 
1721 	if (nfs4_setup_sequence(hdr->ds_clp,
1722 				&hdr->args.seq_args,
1723 				&hdr->res.seq_res,
1724 				task))
1725 		return;
1726 
1727 	ff_layout_read_prepare_common(task, hdr);
1728 }
1729 
1730 static void ff_layout_read_call_done(struct rpc_task *task, void *data)
1731 {
1732 	struct nfs_pgio_header *hdr = data;
1733 
1734 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1735 	    task->tk_status == 0) {
1736 		nfs4_sequence_done(task, &hdr->res.seq_res);
1737 		return;
1738 	}
1739 
1740 	/* Note this may cause RPC to be resent */
1741 	hdr->mds_ops->rpc_call_done(task, hdr);
1742 }
1743 
1744 static void ff_layout_read_count_stats(struct rpc_task *task, void *data)
1745 {
1746 	struct nfs_pgio_header *hdr = data;
1747 
1748 	ff_layout_read_record_layoutstats_done(task, hdr);
1749 	rpc_count_iostats_metrics(task,
1750 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_READ]);
1751 }
1752 
1753 static void ff_layout_read_release(void *data)
1754 {
1755 	struct nfs_pgio_header *hdr = data;
1756 
1757 	ff_layout_read_record_layoutstats_done(&hdr->task, hdr);
1758 	if (test_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags))
1759 		ff_layout_resend_pnfs_read(hdr);
1760 	else if (test_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags))
1761 		ff_layout_reset_read(hdr);
1762 	pnfs_generic_rw_release(data);
1763 }
1764 
1765 
1766 static int ff_layout_write_done_cb(struct rpc_task *task,
1767 				struct nfs_pgio_header *hdr)
1768 {
1769 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(hdr->lseg);
1770 	u32 dss_id = nfs4_ff_layout_calc_dss_id(
1771 		flseg->stripe_unit,
1772 		flseg->mirror_array[hdr->pgio_mirror_idx]->dss_count,
1773 		hdr->args.offset);
1774 	loff_t end_offs = 0;
1775 	int err;
1776 
1777 	if (task->tk_status < 0) {
1778 		ff_layout_io_track_ds_error(hdr->lseg,
1779 					    hdr->pgio_mirror_idx, dss_id,
1780 					    hdr->args.offset, hdr->args.count,
1781 					    &hdr->res.op_status, OP_WRITE,
1782 					    task->tk_status);
1783 		trace_ff_layout_write_error(hdr, task->tk_status);
1784 	}
1785 
1786 	err = ff_layout_async_handle_error(task, hdr->res.op_status,
1787 					   hdr->args.context->state,
1788 					   hdr->ds_clp, hdr->lseg,
1789 					   hdr->pgio_mirror_idx,
1790 					   dss_id);
1791 
1792 	trace_nfs4_pnfs_write(hdr, err);
1793 	clear_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1794 	clear_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1795 	switch (err) {
1796 	case -NFS4ERR_RESET_TO_PNFS:
1797 		set_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1798 		return task->tk_status;
1799 	case -NFS4ERR_RESET_TO_MDS:
1800 		set_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1801 		return task->tk_status;
1802 	case -EAGAIN:
1803 		return -EAGAIN;
1804 	case -NFS4ERR_FATAL_IOERROR:
1805 		task->tk_status = -EIO;
1806 		return 0;
1807 	}
1808 
1809 	if (hdr->res.verf->committed == NFS_FILE_SYNC ||
1810 	    hdr->res.verf->committed == NFS_DATA_SYNC)
1811 		end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
1812 
1813 	/* Note: if the write is unstable, don't set end_offs until commit */
1814 	ff_layout_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
1815 
1816 	/* zero out fattr since we don't care DS attr at all */
1817 	hdr->fattr.valid = 0;
1818 	if (task->tk_status >= 0)
1819 		nfs_writeback_update_inode(hdr);
1820 
1821 	return 0;
1822 }
1823 
1824 static int ff_layout_commit_done_cb(struct rpc_task *task,
1825 				     struct nfs_commit_data *data)
1826 {
1827 	int err;
1828 	u32 idx = calc_mirror_idx_from_commit(data->lseg, data->ds_commit_index);
1829 	u32 dss_id = calc_dss_id_from_commit(data->lseg, data->ds_commit_index);
1830 
1831 	if (task->tk_status < 0) {
1832 		ff_layout_io_track_ds_error(data->lseg, idx, dss_id,
1833 					    data->args.offset, data->args.count,
1834 					    &data->res.op_status, OP_COMMIT,
1835 					    task->tk_status);
1836 		trace_ff_layout_commit_error(data, task->tk_status);
1837 	}
1838 
1839 	err = ff_layout_async_handle_error(task, data->res.op_status,
1840 					   NULL, data->ds_clp, data->lseg, idx,
1841 					   dss_id);
1842 
1843 	trace_nfs4_pnfs_commit_ds(data, err);
1844 	switch (err) {
1845 	case -NFS4ERR_RESET_TO_PNFS:
1846 		pnfs_generic_prepare_to_resend_writes(data);
1847 		return -EAGAIN;
1848 	case -NFS4ERR_RESET_TO_MDS:
1849 		pnfs_generic_prepare_to_resend_writes(data);
1850 		return -EAGAIN;
1851 	case -EAGAIN:
1852 		rpc_restart_call_prepare(task);
1853 		return -EAGAIN;
1854 	case -NFS4ERR_FATAL_IOERROR:
1855 		task->tk_status = -EIO;
1856 		return 0;
1857 	}
1858 
1859 	ff_layout_set_layoutcommit(data->inode, data->lseg, data->lwb);
1860 	return 0;
1861 }
1862 
1863 static void ff_layout_write_record_layoutstats_start(struct rpc_task *task,
1864 		struct nfs_pgio_header *hdr)
1865 {
1866 	struct nfs4_ff_layout_mirror *mirror;
1867 	u32 dss_id;
1868 
1869 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1870 		return;
1871 
1872 	mirror = FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx);
1873 	dss_id = nfs4_ff_layout_calc_dss_id(
1874 		FF_LAYOUT_LSEG(hdr->lseg)->stripe_unit,
1875 		mirror->dss_count,
1876 		hdr->args.offset);
1877 
1878 	nfs4_ff_layout_stat_io_start_write(
1879 		hdr->inode,
1880 		mirror,
1881 		dss_id,
1882 		hdr->args.count,
1883 		task->tk_start);
1884 }
1885 
1886 static void ff_layout_write_record_layoutstats_done(struct rpc_task *task,
1887 		struct nfs_pgio_header *hdr)
1888 {
1889 	struct nfs4_ff_layout_mirror *mirror;
1890 	u32 dss_id;
1891 
1892 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1893 		return;
1894 
1895 	mirror = FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx);
1896 	dss_id = nfs4_ff_layout_calc_dss_id(
1897 		FF_LAYOUT_LSEG(hdr->lseg)->stripe_unit,
1898 		mirror->dss_count,
1899 		hdr->args.offset);
1900 
1901 	nfs4_ff_layout_stat_io_end_write(
1902 		task,
1903 		mirror,
1904 		dss_id,
1905 		hdr->args.count,
1906 		hdr->res.count,
1907 		hdr->res.verf->committed);
1908 	set_bit(NFS_LSEG_LAYOUTRETURN, &hdr->lseg->pls_flags);
1909 }
1910 
1911 static int ff_layout_write_prepare_common(struct rpc_task *task,
1912 					  struct nfs_pgio_header *hdr)
1913 {
1914 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1915 		rpc_exit(task, -EIO);
1916 		return -EIO;
1917 	}
1918 
1919 	if (!pnfs_is_valid_lseg(hdr->lseg)) {
1920 		rpc_exit(task, -EAGAIN);
1921 		return -EAGAIN;
1922 	}
1923 
1924 	ff_layout_write_record_layoutstats_start(task, hdr);
1925 	return 0;
1926 }
1927 
1928 static void ff_layout_write_prepare_v3(struct rpc_task *task, void *data)
1929 {
1930 	struct nfs_pgio_header *hdr = data;
1931 
1932 	if (ff_layout_write_prepare_common(task, hdr))
1933 		return;
1934 
1935 	rpc_call_start(task);
1936 }
1937 
1938 static void ff_layout_write_prepare_v4(struct rpc_task *task, void *data)
1939 {
1940 	struct nfs_pgio_header *hdr = data;
1941 
1942 	if (nfs4_setup_sequence(hdr->ds_clp,
1943 				&hdr->args.seq_args,
1944 				&hdr->res.seq_res,
1945 				task))
1946 		return;
1947 
1948 	ff_layout_write_prepare_common(task, hdr);
1949 }
1950 
1951 static void ff_layout_write_call_done(struct rpc_task *task, void *data)
1952 {
1953 	struct nfs_pgio_header *hdr = data;
1954 
1955 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1956 	    task->tk_status == 0) {
1957 		nfs4_sequence_done(task, &hdr->res.seq_res);
1958 		return;
1959 	}
1960 
1961 	/* Note this may cause RPC to be resent */
1962 	hdr->mds_ops->rpc_call_done(task, hdr);
1963 }
1964 
1965 static void ff_layout_write_count_stats(struct rpc_task *task, void *data)
1966 {
1967 	struct nfs_pgio_header *hdr = data;
1968 
1969 	ff_layout_write_record_layoutstats_done(task, hdr);
1970 	rpc_count_iostats_metrics(task,
1971 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_WRITE]);
1972 }
1973 
1974 static void ff_layout_write_release(void *data)
1975 {
1976 	struct nfs_pgio_header *hdr = data;
1977 
1978 	ff_layout_write_record_layoutstats_done(&hdr->task, hdr);
1979 	if (test_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags)) {
1980 		ff_layout_send_layouterror(hdr->lseg);
1981 		ff_layout_reset_write(hdr, true);
1982 	} else if (test_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags))
1983 		ff_layout_reset_write(hdr, false);
1984 	pnfs_generic_rw_release(data);
1985 }
1986 
1987 static void ff_layout_commit_record_layoutstats_start(struct rpc_task *task,
1988 		struct nfs_commit_data *cdata)
1989 {
1990 	u32 idx, dss_id;
1991 
1992 	if (test_and_set_bit(NFS_IOHDR_STAT, &cdata->flags))
1993 		return;
1994 
1995 	idx = calc_mirror_idx_from_commit(cdata->lseg, cdata->ds_commit_index);
1996 	dss_id = calc_dss_id_from_commit(cdata->lseg, cdata->ds_commit_index);
1997 	nfs4_ff_layout_stat_io_start_write(cdata->inode,
1998 			FF_LAYOUT_COMP(cdata->lseg, idx),
1999 			dss_id,
2000 			0, task->tk_start);
2001 }
2002 
2003 static void ff_layout_commit_record_layoutstats_done(struct rpc_task *task,
2004 		struct nfs_commit_data *cdata)
2005 {
2006 	struct nfs_page *req;
2007 	__u64 count = 0;
2008 	u32 idx, dss_id;
2009 
2010 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &cdata->flags))
2011 		return;
2012 
2013 	if (task->tk_status == 0) {
2014 		list_for_each_entry(req, &cdata->pages, wb_list)
2015 			count += req->wb_bytes;
2016 	}
2017 
2018 	idx = calc_mirror_idx_from_commit(cdata->lseg, cdata->ds_commit_index);
2019 	dss_id = calc_dss_id_from_commit(cdata->lseg, cdata->ds_commit_index);
2020 	nfs4_ff_layout_stat_io_end_write(task,
2021 			FF_LAYOUT_COMP(cdata->lseg, idx),
2022 			dss_id,
2023 			count, count, NFS_FILE_SYNC);
2024 	set_bit(NFS_LSEG_LAYOUTRETURN, &cdata->lseg->pls_flags);
2025 }
2026 
2027 static int ff_layout_commit_prepare_common(struct rpc_task *task,
2028 					   struct nfs_commit_data *cdata)
2029 {
2030 	if (!pnfs_is_valid_lseg(cdata->lseg)) {
2031 		rpc_exit(task, -EAGAIN);
2032 		return -EAGAIN;
2033 	}
2034 
2035 	ff_layout_commit_record_layoutstats_start(task, cdata);
2036 	return 0;
2037 }
2038 
2039 static void ff_layout_commit_prepare_v3(struct rpc_task *task, void *data)
2040 {
2041 	if (ff_layout_commit_prepare_common(task, data))
2042 		return;
2043 
2044 	rpc_call_start(task);
2045 }
2046 
2047 static void ff_layout_commit_prepare_v4(struct rpc_task *task, void *data)
2048 {
2049 	struct nfs_commit_data *wdata = data;
2050 
2051 	if (nfs4_setup_sequence(wdata->ds_clp,
2052 				&wdata->args.seq_args,
2053 				&wdata->res.seq_res,
2054 				task))
2055 		return;
2056 	ff_layout_commit_prepare_common(task, data);
2057 }
2058 
2059 static void ff_layout_commit_done(struct rpc_task *task, void *data)
2060 {
2061 	pnfs_generic_write_commit_done(task, data);
2062 }
2063 
2064 static void ff_layout_commit_count_stats(struct rpc_task *task, void *data)
2065 {
2066 	struct nfs_commit_data *cdata = data;
2067 
2068 	ff_layout_commit_record_layoutstats_done(task, cdata);
2069 	rpc_count_iostats_metrics(task,
2070 	    &NFS_CLIENT(cdata->inode)->cl_metrics[NFSPROC4_CLNT_COMMIT]);
2071 }
2072 
2073 static void ff_layout_commit_release(void *data)
2074 {
2075 	struct nfs_commit_data *cdata = data;
2076 
2077 	ff_layout_commit_record_layoutstats_done(&cdata->task, cdata);
2078 	pnfs_generic_commit_release(data);
2079 }
2080 
2081 static const struct rpc_call_ops ff_layout_read_call_ops_v3 = {
2082 	.rpc_call_prepare = ff_layout_read_prepare_v3,
2083 	.rpc_call_done = ff_layout_read_call_done,
2084 	.rpc_count_stats = ff_layout_read_count_stats,
2085 	.rpc_release = ff_layout_read_release,
2086 };
2087 
2088 static const struct rpc_call_ops ff_layout_read_call_ops_v4 = {
2089 	.rpc_call_prepare = ff_layout_read_prepare_v4,
2090 	.rpc_call_done = ff_layout_read_call_done,
2091 	.rpc_count_stats = ff_layout_read_count_stats,
2092 	.rpc_release = ff_layout_read_release,
2093 };
2094 
2095 static const struct rpc_call_ops ff_layout_write_call_ops_v3 = {
2096 	.rpc_call_prepare = ff_layout_write_prepare_v3,
2097 	.rpc_call_done = ff_layout_write_call_done,
2098 	.rpc_count_stats = ff_layout_write_count_stats,
2099 	.rpc_release = ff_layout_write_release,
2100 };
2101 
2102 static const struct rpc_call_ops ff_layout_write_call_ops_v4 = {
2103 	.rpc_call_prepare = ff_layout_write_prepare_v4,
2104 	.rpc_call_done = ff_layout_write_call_done,
2105 	.rpc_count_stats = ff_layout_write_count_stats,
2106 	.rpc_release = ff_layout_write_release,
2107 };
2108 
2109 static const struct rpc_call_ops ff_layout_commit_call_ops_v3 = {
2110 	.rpc_call_prepare = ff_layout_commit_prepare_v3,
2111 	.rpc_call_done = ff_layout_commit_done,
2112 	.rpc_count_stats = ff_layout_commit_count_stats,
2113 	.rpc_release = ff_layout_commit_release,
2114 };
2115 
2116 static const struct rpc_call_ops ff_layout_commit_call_ops_v4 = {
2117 	.rpc_call_prepare = ff_layout_commit_prepare_v4,
2118 	.rpc_call_done = ff_layout_commit_done,
2119 	.rpc_count_stats = ff_layout_commit_count_stats,
2120 	.rpc_release = ff_layout_commit_release,
2121 };
2122 
2123 static enum pnfs_try_status
2124 ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
2125 {
2126 	struct pnfs_layout_segment *lseg = hdr->lseg;
2127 	struct nfs4_pnfs_ds *ds;
2128 	struct rpc_clnt *ds_clnt;
2129 	struct nfsd_file *localio;
2130 	struct nfs4_ff_layout_mirror *mirror;
2131 	const struct cred *ds_cred;
2132 	loff_t offset = hdr->args.offset;
2133 	u32 idx = hdr->pgio_mirror_idx;
2134 	int vers;
2135 	struct nfs_fh *fh;
2136 	u32 dss_id;
2137 	bool ds_fatal_error = false;
2138 
2139 	dprintk("--> %s ino %lu pgbase %u req %zu@%llu\n",
2140 		__func__, hdr->inode->i_ino,
2141 		hdr->args.pgbase, (size_t)hdr->args.count, offset);
2142 
2143 	mirror = FF_LAYOUT_COMP(lseg, idx);
2144 	dss_id = nfs4_ff_layout_calc_dss_id(
2145 		FF_LAYOUT_LSEG(lseg)->stripe_unit,
2146 		mirror->dss_count,
2147 		offset);
2148 	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, dss_id, false);
2149 	if (IS_ERR(ds)) {
2150 		ds_fatal_error = nfs_error_is_fatal(PTR_ERR(ds));
2151 		goto out_failed;
2152 	}
2153 
2154 	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,
2155 						   hdr->inode, dss_id);
2156 	if (IS_ERR(ds_clnt))
2157 		goto out_failed;
2158 
2159 	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, hdr->cred, dss_id);
2160 	if (!ds_cred)
2161 		goto out_failed;
2162 
2163 	vers = nfs4_ff_layout_ds_version(mirror, dss_id);
2164 
2165 	dprintk("%s USE DS: %s cl_count %d vers %d\n", __func__,
2166 		ds->ds_remotestr, refcount_read(&ds->ds_clp->cl_count), vers);
2167 
2168 	hdr->pgio_done_cb = ff_layout_read_done_cb;
2169 	refcount_inc(&ds->ds_clp->cl_count);
2170 	hdr->ds_clp = ds->ds_clp;
2171 	fh = nfs4_ff_layout_select_ds_fh(mirror, dss_id);
2172 	if (fh)
2173 		hdr->args.fh = fh;
2174 
2175 	nfs4_ff_layout_select_ds_stateid(mirror, dss_id, &hdr->args.stateid);
2176 
2177 	/*
2178 	 * Note that if we ever decide to split across DSes,
2179 	 * then we may need to handle dense-like offsets.
2180 	 */
2181 	hdr->args.offset = offset;
2182 	hdr->mds_offset = offset;
2183 
2184 	/* Start IO accounting for local read */
2185 	localio = ff_local_open_fh(lseg, idx, dss_id, ds->ds_clp, ds_cred, fh,
2186 				FMODE_READ);
2187 	if (localio) {
2188 		hdr->task.tk_start = ktime_get();
2189 		ff_layout_read_record_layoutstats_start(&hdr->task, hdr);
2190 	}
2191 
2192 	/* Perform an asynchronous read to ds */
2193 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
2194 			  vers == 3 ? &ff_layout_read_call_ops_v3 :
2195 				      &ff_layout_read_call_ops_v4,
2196 			  0, RPC_TASK_SOFTCONN, localio);
2197 	put_cred(ds_cred);
2198 	return PNFS_ATTEMPTED;
2199 
2200 out_failed:
2201 	if (ff_layout_avoid_mds_available_ds(lseg) && !ds_fatal_error)
2202 		return PNFS_TRY_AGAIN;
2203 	trace_pnfs_mds_fallback_read_pagelist(hdr->inode,
2204 			hdr->args.offset, hdr->args.count,
2205 			IOMODE_READ, NFS_I(hdr->inode)->layout, lseg);
2206 	return PNFS_NOT_ATTEMPTED;
2207 }
2208 
2209 /* Perform async writes. */
2210 static enum pnfs_try_status
2211 ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
2212 {
2213 	struct pnfs_layout_segment *lseg = hdr->lseg;
2214 	struct nfs4_pnfs_ds *ds;
2215 	struct rpc_clnt *ds_clnt;
2216 	struct nfsd_file *localio;
2217 	struct nfs4_ff_layout_mirror *mirror;
2218 	const struct cred *ds_cred;
2219 	loff_t offset = hdr->args.offset;
2220 	int vers;
2221 	struct nfs_fh *fh;
2222 	u32 idx = hdr->pgio_mirror_idx;
2223 	u32 dss_id;
2224 	bool ds_fatal_error = false;
2225 
2226 	mirror = FF_LAYOUT_COMP(lseg, idx);
2227 	dss_id = nfs4_ff_layout_calc_dss_id(
2228 		FF_LAYOUT_LSEG(lseg)->stripe_unit,
2229 		mirror->dss_count,
2230 		offset);
2231 	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, dss_id, true);
2232 	if (IS_ERR(ds)) {
2233 		ds_fatal_error = nfs_error_is_fatal(PTR_ERR(ds));
2234 		goto out_failed;
2235 	}
2236 
2237 	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,
2238 						   hdr->inode, dss_id);
2239 	if (IS_ERR(ds_clnt))
2240 		goto out_failed;
2241 
2242 	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, hdr->cred, dss_id);
2243 	if (!ds_cred)
2244 		goto out_failed;
2245 
2246 	vers = nfs4_ff_layout_ds_version(mirror, dss_id);
2247 
2248 	dprintk("%s ino %lu sync %d req %zu@%llu DS: %s cl_count %d vers %d\n",
2249 		__func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
2250 		offset, ds->ds_remotestr, refcount_read(&ds->ds_clp->cl_count),
2251 		vers);
2252 
2253 	hdr->pgio_done_cb = ff_layout_write_done_cb;
2254 	refcount_inc(&ds->ds_clp->cl_count);
2255 	hdr->ds_clp = ds->ds_clp;
2256 	hdr->ds_commit_idx = calc_commit_idx(lseg, idx, dss_id);
2257 	fh = nfs4_ff_layout_select_ds_fh(mirror, dss_id);
2258 	if (fh)
2259 		hdr->args.fh = fh;
2260 
2261 	nfs4_ff_layout_select_ds_stateid(mirror, dss_id, &hdr->args.stateid);
2262 
2263 	/*
2264 	 * Note that if we ever decide to split across DSes,
2265 	 * then we may need to handle dense-like offsets.
2266 	 */
2267 	hdr->args.offset = offset;
2268 
2269 	/* Start IO accounting for local write */
2270 	localio = ff_local_open_fh(lseg, idx, dss_id, ds->ds_clp, ds_cred, fh,
2271 				   FMODE_READ|FMODE_WRITE);
2272 	if (localio) {
2273 		hdr->task.tk_start = ktime_get();
2274 		ff_layout_write_record_layoutstats_start(&hdr->task, hdr);
2275 	}
2276 
2277 	/* Perform an asynchronous write */
2278 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
2279 			  vers == 3 ? &ff_layout_write_call_ops_v3 :
2280 				      &ff_layout_write_call_ops_v4,
2281 			  sync, RPC_TASK_SOFTCONN, localio);
2282 	put_cred(ds_cred);
2283 	return PNFS_ATTEMPTED;
2284 
2285 out_failed:
2286 	if (ff_layout_avoid_mds_available_ds(lseg) && !ds_fatal_error)
2287 		return PNFS_TRY_AGAIN;
2288 	trace_pnfs_mds_fallback_write_pagelist(hdr->inode,
2289 			hdr->args.offset, hdr->args.count,
2290 			IOMODE_RW, NFS_I(hdr->inode)->layout, lseg);
2291 	return PNFS_NOT_ATTEMPTED;
2292 }
2293 
2294 static struct nfs_fh *
2295 select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i, u32 dss_id)
2296 {
2297 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
2298 
2299 	/* FIXME: Assume that there is only one NFS version available
2300 	 * for the DS.
2301 	 */
2302 	return &flseg->mirror_array[i]->dss[dss_id].fh_versions[0];
2303 }
2304 
2305 static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
2306 {
2307 	struct pnfs_layout_segment *lseg = data->lseg;
2308 	struct nfs4_pnfs_ds *ds;
2309 	struct rpc_clnt *ds_clnt;
2310 	struct nfsd_file *localio;
2311 	struct nfs4_ff_layout_mirror *mirror;
2312 	const struct cred *ds_cred;
2313 	u32 idx, dss_id;
2314 	int vers, ret;
2315 	struct nfs_fh *fh;
2316 
2317 	if (!lseg || !(pnfs_is_valid_lseg(lseg) ||
2318 	    test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags)))
2319 		goto out_err;
2320 
2321 	idx = calc_mirror_idx_from_commit(lseg, data->ds_commit_index);
2322 	mirror = FF_LAYOUT_COMP(lseg, idx);
2323 	dss_id = calc_dss_id_from_commit(lseg, data->ds_commit_index);
2324 	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, dss_id, true);
2325 	if (IS_ERR(ds))
2326 		goto out_err;
2327 
2328 	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,
2329 						   data->inode, dss_id);
2330 	if (IS_ERR(ds_clnt))
2331 		goto out_err;
2332 
2333 	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, data->cred, dss_id);
2334 	if (!ds_cred)
2335 		goto out_err;
2336 
2337 	vers = nfs4_ff_layout_ds_version(mirror, dss_id);
2338 
2339 	dprintk("%s ino %lu, how %d cl_count %d vers %d\n", __func__,
2340 		data->inode->i_ino, how, refcount_read(&ds->ds_clp->cl_count),
2341 		vers);
2342 	data->commit_done_cb = ff_layout_commit_done_cb;
2343 	data->cred = ds_cred;
2344 	refcount_inc(&ds->ds_clp->cl_count);
2345 	data->ds_clp = ds->ds_clp;
2346 	fh = select_ds_fh_from_commit(lseg, idx, dss_id);
2347 	if (fh)
2348 		data->args.fh = fh;
2349 
2350 	/* Start IO accounting for local commit */
2351 	localio = ff_local_open_fh(lseg, idx, dss_id, ds->ds_clp, ds_cred, fh,
2352 				   FMODE_READ|FMODE_WRITE);
2353 	if (localio) {
2354 		data->task.tk_start = ktime_get();
2355 		ff_layout_commit_record_layoutstats_start(&data->task, data);
2356 	}
2357 
2358 	ret = nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
2359 				   vers == 3 ? &ff_layout_commit_call_ops_v3 :
2360 					       &ff_layout_commit_call_ops_v4,
2361 				   how, RPC_TASK_SOFTCONN, localio);
2362 	put_cred(ds_cred);
2363 	return ret;
2364 out_err:
2365 	pnfs_generic_prepare_to_resend_writes(data);
2366 	pnfs_generic_commit_release(data);
2367 	return -EAGAIN;
2368 }
2369 
2370 static int
2371 ff_layout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
2372 			   int how, struct nfs_commit_info *cinfo)
2373 {
2374 	return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
2375 					    ff_layout_initiate_commit);
2376 }
2377 
2378 static bool ff_layout_match_rw(const struct rpc_task *task,
2379 			       const struct nfs_pgio_header *hdr,
2380 			       const struct pnfs_layout_segment *lseg)
2381 {
2382 	return hdr->lseg == lseg;
2383 }
2384 
2385 static bool ff_layout_match_commit(const struct rpc_task *task,
2386 				   const struct nfs_commit_data *cdata,
2387 				   const struct pnfs_layout_segment *lseg)
2388 {
2389 	return cdata->lseg == lseg;
2390 }
2391 
2392 static bool ff_layout_match_io(const struct rpc_task *task, const void *data)
2393 {
2394 	const struct rpc_call_ops *ops = task->tk_ops;
2395 
2396 	if (ops == &ff_layout_read_call_ops_v3 ||
2397 	    ops == &ff_layout_read_call_ops_v4 ||
2398 	    ops == &ff_layout_write_call_ops_v3 ||
2399 	    ops == &ff_layout_write_call_ops_v4)
2400 		return ff_layout_match_rw(task, task->tk_calldata, data);
2401 	if (ops == &ff_layout_commit_call_ops_v3 ||
2402 	    ops == &ff_layout_commit_call_ops_v4)
2403 		return ff_layout_match_commit(task, task->tk_calldata, data);
2404 	return false;
2405 }
2406 
2407 static void ff_layout_cancel_io(struct pnfs_layout_segment *lseg)
2408 {
2409 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
2410 	struct nfs4_ff_layout_mirror *mirror;
2411 	struct nfs4_ff_layout_ds *mirror_ds;
2412 	struct nfs4_pnfs_ds *ds;
2413 	struct nfs_client *ds_clp;
2414 	struct rpc_clnt *clnt;
2415 	u32 idx, dss_id;
2416 
2417 	for (idx = 0; idx < flseg->mirror_array_cnt; idx++) {
2418 		mirror = flseg->mirror_array[idx];
2419 		for (dss_id = 0; dss_id < mirror->dss_count; dss_id++) {
2420 			mirror_ds = mirror->dss[dss_id].mirror_ds;
2421 			if (IS_ERR_OR_NULL(mirror_ds))
2422 				continue;
2423 			ds = mirror->dss[dss_id].mirror_ds->ds;
2424 			if (!ds)
2425 				continue;
2426 			ds_clp = ds->ds_clp;
2427 			if (!ds_clp)
2428 				continue;
2429 			clnt = ds_clp->cl_rpcclient;
2430 			if (!clnt)
2431 				continue;
2432 			if (!rpc_cancel_tasks(clnt, -EAGAIN,
2433 					      ff_layout_match_io, lseg))
2434 				continue;
2435 			rpc_clnt_disconnect(clnt);
2436 		}
2437 	}
2438 }
2439 
2440 static struct pnfs_ds_commit_info *
2441 ff_layout_get_ds_info(struct inode *inode)
2442 {
2443 	struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
2444 
2445 	if (layout == NULL)
2446 		return NULL;
2447 
2448 	return &FF_LAYOUT_FROM_HDR(layout)->commit_info;
2449 }
2450 
2451 static void
2452 ff_layout_setup_ds_info(struct pnfs_ds_commit_info *fl_cinfo,
2453 		struct pnfs_layout_segment *lseg)
2454 {
2455 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
2456 	struct inode *inode = lseg->pls_layout->plh_inode;
2457 	struct pnfs_commit_array *array, *new;
2458 	u32 size = flseg->mirror_array_cnt * flseg->mirror_array[0]->dss_count;
2459 
2460 	new = pnfs_alloc_commit_array(size,
2461 				      nfs_io_gfp_mask());
2462 	if (new) {
2463 		spin_lock(&inode->i_lock);
2464 		array = pnfs_add_commit_array(fl_cinfo, new, lseg);
2465 		spin_unlock(&inode->i_lock);
2466 		if (array != new)
2467 			pnfs_free_commit_array(new);
2468 	}
2469 }
2470 
2471 static void
2472 ff_layout_release_ds_info(struct pnfs_ds_commit_info *fl_cinfo,
2473 		struct inode *inode)
2474 {
2475 	spin_lock(&inode->i_lock);
2476 	pnfs_generic_ds_cinfo_destroy(fl_cinfo);
2477 	spin_unlock(&inode->i_lock);
2478 }
2479 
2480 static void
2481 ff_layout_free_deviceid_node(struct nfs4_deviceid_node *d)
2482 {
2483 	nfs4_ff_layout_free_deviceid(container_of(d, struct nfs4_ff_layout_ds,
2484 						  id_node));
2485 }
2486 
2487 static int ff_layout_encode_ioerr(struct xdr_stream *xdr,
2488 				  const struct nfs4_layoutreturn_args *args,
2489 				  const struct nfs4_flexfile_layoutreturn_args *ff_args)
2490 {
2491 	__be32 *start;
2492 
2493 	start = xdr_reserve_space(xdr, 4);
2494 	if (unlikely(!start))
2495 		return -E2BIG;
2496 
2497 	*start = cpu_to_be32(ff_args->num_errors);
2498 	/* This assume we always return _ALL_ layouts */
2499 	return ff_layout_encode_ds_ioerr(xdr, &ff_args->errors);
2500 }
2501 
2502 static void
2503 ff_layout_encode_ff_iostat_head(struct xdr_stream *xdr,
2504 			    const nfs4_stateid *stateid,
2505 			    const struct nfs42_layoutstat_devinfo *devinfo)
2506 {
2507 	__be32 *p;
2508 
2509 	p = xdr_reserve_space(xdr, 8 + 8);
2510 	p = xdr_encode_hyper(p, devinfo->offset);
2511 	p = xdr_encode_hyper(p, devinfo->length);
2512 	encode_opaque_fixed(xdr, stateid->data, NFS4_STATEID_SIZE);
2513 	p = xdr_reserve_space(xdr, 4*8);
2514 	p = xdr_encode_hyper(p, devinfo->read_count);
2515 	p = xdr_encode_hyper(p, devinfo->read_bytes);
2516 	p = xdr_encode_hyper(p, devinfo->write_count);
2517 	p = xdr_encode_hyper(p, devinfo->write_bytes);
2518 	encode_opaque_fixed(xdr, devinfo->dev_id.data, NFS4_DEVICEID4_SIZE);
2519 }
2520 
2521 static void
2522 ff_layout_encode_ff_iostat(struct xdr_stream *xdr,
2523 			    const nfs4_stateid *stateid,
2524 			    const struct nfs42_layoutstat_devinfo *devinfo)
2525 {
2526 	ff_layout_encode_ff_iostat_head(xdr, stateid, devinfo);
2527 	ff_layout_encode_ff_layoutupdate(xdr, devinfo,
2528 			devinfo->ld_private.data);
2529 }
2530 
2531 /* report nothing for now */
2532 static void ff_layout_encode_iostats_array(struct xdr_stream *xdr,
2533 		const struct nfs4_layoutreturn_args *args,
2534 		struct nfs4_flexfile_layoutreturn_args *ff_args)
2535 {
2536 	__be32 *p;
2537 	int i;
2538 
2539 	p = xdr_reserve_space(xdr, 4);
2540 	*p = cpu_to_be32(ff_args->num_dev);
2541 	for (i = 0; i < ff_args->num_dev; i++)
2542 		ff_layout_encode_ff_iostat(xdr,
2543 				&args->layout->plh_stateid,
2544 				&ff_args->devinfo[i]);
2545 }
2546 
2547 static void
2548 ff_layout_free_iostats_array(struct nfs42_layoutstat_devinfo *devinfo,
2549 		unsigned int num_entries)
2550 {
2551 	unsigned int i;
2552 
2553 	for (i = 0; i < num_entries; i++) {
2554 		if (!devinfo[i].ld_private.ops)
2555 			continue;
2556 		if (!devinfo[i].ld_private.ops->free)
2557 			continue;
2558 		devinfo[i].ld_private.ops->free(&devinfo[i].ld_private);
2559 	}
2560 }
2561 
2562 static struct nfs4_deviceid_node *
2563 ff_layout_alloc_deviceid_node(struct nfs_server *server,
2564 			      struct pnfs_device *pdev, gfp_t gfp_flags)
2565 {
2566 	struct nfs4_ff_layout_ds *dsaddr;
2567 
2568 	dsaddr = nfs4_ff_alloc_deviceid_node(server, pdev, gfp_flags);
2569 	if (!dsaddr)
2570 		return NULL;
2571 	return &dsaddr->id_node;
2572 }
2573 
2574 static void
2575 ff_layout_encode_layoutreturn(struct xdr_stream *xdr,
2576 		const void *voidargs,
2577 		const struct nfs4_xdr_opaque_data *ff_opaque)
2578 {
2579 	const struct nfs4_layoutreturn_args *args = voidargs;
2580 	struct nfs4_flexfile_layoutreturn_args *ff_args = ff_opaque->data;
2581 	struct xdr_buf tmp_buf = {
2582 		.head = {
2583 			[0] = {
2584 				.iov_base = page_address(ff_args->pages[0]),
2585 			},
2586 		},
2587 		.buflen = PAGE_SIZE,
2588 	};
2589 	struct xdr_stream tmp_xdr;
2590 	__be32 *start;
2591 
2592 	dprintk("%s: Begin\n", __func__);
2593 
2594 	xdr_init_encode(&tmp_xdr, &tmp_buf, NULL, NULL);
2595 
2596 	ff_layout_encode_ioerr(&tmp_xdr, args, ff_args);
2597 	ff_layout_encode_iostats_array(&tmp_xdr, args, ff_args);
2598 
2599 	start = xdr_reserve_space(xdr, 4);
2600 	*start = cpu_to_be32(tmp_buf.len);
2601 	xdr_write_pages(xdr, ff_args->pages, 0, tmp_buf.len);
2602 
2603 	dprintk("%s: Return\n", __func__);
2604 }
2605 
2606 static void
2607 ff_layout_free_layoutreturn(struct nfs4_xdr_opaque_data *args)
2608 {
2609 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2610 
2611 	if (!args->data)
2612 		return;
2613 	ff_args = args->data;
2614 	args->data = NULL;
2615 
2616 	ff_layout_free_ds_ioerr(&ff_args->errors);
2617 	ff_layout_free_iostats_array(ff_args->devinfo, ff_args->num_dev);
2618 
2619 	put_page(ff_args->pages[0]);
2620 	kfree(ff_args);
2621 }
2622 
2623 static const struct nfs4_xdr_opaque_ops layoutreturn_ops = {
2624 	.encode = ff_layout_encode_layoutreturn,
2625 	.free = ff_layout_free_layoutreturn,
2626 };
2627 
2628 static int
2629 ff_layout_prepare_layoutreturn(struct nfs4_layoutreturn_args *args)
2630 {
2631 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2632 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(args->layout);
2633 
2634 	ff_args = kmalloc_obj(*ff_args, nfs_io_gfp_mask());
2635 	if (!ff_args)
2636 		goto out_nomem;
2637 	ff_args->pages[0] = alloc_page(nfs_io_gfp_mask());
2638 	if (!ff_args->pages[0])
2639 		goto out_nomem_free;
2640 
2641 	INIT_LIST_HEAD(&ff_args->errors);
2642 	ff_args->num_errors = ff_layout_fetch_ds_ioerr(args->layout,
2643 			&args->range, &ff_args->errors,
2644 			FF_LAYOUTRETURN_MAXERR);
2645 
2646 	spin_lock(&args->inode->i_lock);
2647 	ff_args->num_dev = ff_layout_mirror_prepare_stats(
2648 		&ff_layout->generic_hdr, &ff_args->devinfo[0],
2649 		ARRAY_SIZE(ff_args->devinfo), NFS4_FF_OP_LAYOUTRETURN);
2650 	spin_unlock(&args->inode->i_lock);
2651 
2652 	args->ld_private->ops = &layoutreturn_ops;
2653 	args->ld_private->data = ff_args;
2654 	return 0;
2655 out_nomem_free:
2656 	kfree(ff_args);
2657 out_nomem:
2658 	return -ENOMEM;
2659 }
2660 
2661 #ifdef CONFIG_NFS_V4_2
2662 void
2663 ff_layout_send_layouterror(struct pnfs_layout_segment *lseg)
2664 {
2665 	struct pnfs_layout_hdr *lo = lseg->pls_layout;
2666 	struct nfs42_layout_error *errors;
2667 	LIST_HEAD(head);
2668 
2669 	if (!nfs_server_capable(lo->plh_inode, NFS_CAP_LAYOUTERROR))
2670 		return;
2671 	ff_layout_fetch_ds_ioerr(lo, &lseg->pls_range, &head, -1);
2672 	if (list_empty(&head))
2673 		return;
2674 
2675 	errors = kmalloc_objs(*errors, NFS42_LAYOUTERROR_MAX, nfs_io_gfp_mask());
2676 	if (errors != NULL) {
2677 		const struct nfs4_ff_layout_ds_err *pos;
2678 		size_t n = 0;
2679 
2680 		list_for_each_entry(pos, &head, list) {
2681 			errors[n].offset = pos->offset;
2682 			errors[n].length = pos->length;
2683 			nfs4_stateid_copy(&errors[n].stateid, &pos->stateid);
2684 			errors[n].errors[0].dev_id = pos->deviceid;
2685 			errors[n].errors[0].status = pos->status;
2686 			errors[n].errors[0].opnum = pos->opnum;
2687 			n++;
2688 			if (!list_is_last(&pos->list, &head) &&
2689 			    n < NFS42_LAYOUTERROR_MAX)
2690 				continue;
2691 			if (nfs42_proc_layouterror(lseg, errors, n) < 0)
2692 				break;
2693 			n = 0;
2694 		}
2695 		kfree(errors);
2696 	}
2697 	ff_layout_free_ds_ioerr(&head);
2698 }
2699 #else
2700 void
2701 ff_layout_send_layouterror(struct pnfs_layout_segment *lseg)
2702 {
2703 }
2704 #endif
2705 
2706 static int
2707 ff_layout_ntop4(const struct sockaddr *sap, char *buf, const size_t buflen)
2708 {
2709 	const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
2710 
2711 	return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
2712 }
2713 
2714 static size_t
2715 ff_layout_ntop6_noscopeid(const struct sockaddr *sap, char *buf,
2716 			  const int buflen)
2717 {
2718 	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
2719 	const struct in6_addr *addr = &sin6->sin6_addr;
2720 
2721 	/*
2722 	 * RFC 4291, Section 2.2.2
2723 	 *
2724 	 * Shorthanded ANY address
2725 	 */
2726 	if (ipv6_addr_any(addr))
2727 		return snprintf(buf, buflen, "::");
2728 
2729 	/*
2730 	 * RFC 4291, Section 2.2.2
2731 	 *
2732 	 * Shorthanded loopback address
2733 	 */
2734 	if (ipv6_addr_loopback(addr))
2735 		return snprintf(buf, buflen, "::1");
2736 
2737 	/*
2738 	 * RFC 4291, Section 2.2.3
2739 	 *
2740 	 * Special presentation address format for mapped v4
2741 	 * addresses.
2742 	 */
2743 	if (ipv6_addr_v4mapped(addr))
2744 		return snprintf(buf, buflen, "::ffff:%pI4",
2745 					&addr->s6_addr32[3]);
2746 
2747 	/*
2748 	 * RFC 4291, Section 2.2.1
2749 	 */
2750 	return snprintf(buf, buflen, "%pI6c", addr);
2751 }
2752 
2753 /* Derived from rpc_sockaddr2uaddr */
2754 static void
2755 ff_layout_encode_netaddr(struct xdr_stream *xdr, struct nfs4_pnfs_ds_addr *da)
2756 {
2757 	struct sockaddr *sap = (struct sockaddr *)&da->da_addr;
2758 	char portbuf[RPCBIND_MAXUADDRPLEN];
2759 	char addrbuf[RPCBIND_MAXUADDRLEN];
2760 	unsigned short port;
2761 	int len, netid_len;
2762 	__be32 *p;
2763 
2764 	switch (sap->sa_family) {
2765 	case AF_INET:
2766 		if (ff_layout_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
2767 			return;
2768 		port = ntohs(((struct sockaddr_in *)sap)->sin_port);
2769 		break;
2770 	case AF_INET6:
2771 		if (ff_layout_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
2772 			return;
2773 		port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
2774 		break;
2775 	default:
2776 		WARN_ON_ONCE(1);
2777 		return;
2778 	}
2779 
2780 	snprintf(portbuf, sizeof(portbuf), ".%u.%u", port >> 8, port & 0xff);
2781 	len = strlcat(addrbuf, portbuf, sizeof(addrbuf));
2782 
2783 	netid_len = strlen(da->da_netid);
2784 	p = xdr_reserve_space(xdr, 4 + netid_len);
2785 	xdr_encode_opaque(p, da->da_netid, netid_len);
2786 
2787 	p = xdr_reserve_space(xdr, 4 + len);
2788 	xdr_encode_opaque(p, addrbuf, len);
2789 }
2790 
2791 static void
2792 ff_layout_encode_nfstime(struct xdr_stream *xdr,
2793 			 ktime_t t)
2794 {
2795 	struct timespec64 ts;
2796 	__be32 *p;
2797 
2798 	p = xdr_reserve_space(xdr, 12);
2799 	ts = ktime_to_timespec64(t);
2800 	p = xdr_encode_hyper(p, ts.tv_sec);
2801 	*p++ = cpu_to_be32(ts.tv_nsec);
2802 }
2803 
2804 static void
2805 ff_layout_encode_io_latency(struct xdr_stream *xdr,
2806 			    struct nfs4_ff_io_stat *stat)
2807 {
2808 	__be32 *p;
2809 
2810 	p = xdr_reserve_space(xdr, 5 * 8);
2811 	p = xdr_encode_hyper(p, stat->ops_requested);
2812 	p = xdr_encode_hyper(p, stat->bytes_requested);
2813 	p = xdr_encode_hyper(p, stat->ops_completed);
2814 	p = xdr_encode_hyper(p, stat->bytes_completed);
2815 	p = xdr_encode_hyper(p, stat->bytes_not_delivered);
2816 	ff_layout_encode_nfstime(xdr, stat->total_busy_time);
2817 	ff_layout_encode_nfstime(xdr, stat->aggregate_completion_time);
2818 }
2819 
2820 static void
2821 ff_layout_encode_ff_layoutupdate(struct xdr_stream *xdr,
2822 			      const struct nfs42_layoutstat_devinfo *devinfo,
2823 			      struct nfs4_ff_layout_ds_stripe *dss_info)
2824 {
2825 	struct nfs4_pnfs_ds_addr *da;
2826 	struct nfs4_pnfs_ds *ds = dss_info->mirror_ds->ds;
2827 	struct nfs_fh *fh = &dss_info->fh_versions[0];
2828 	__be32 *p;
2829 
2830 	da = list_first_entry(&ds->ds_addrs, struct nfs4_pnfs_ds_addr, da_node);
2831 	dprintk("%s: DS %s: encoding address %s\n",
2832 		__func__, ds->ds_remotestr, da->da_remotestr);
2833 	/* netaddr4 */
2834 	ff_layout_encode_netaddr(xdr, da);
2835 	/* nfs_fh4 */
2836 	p = xdr_reserve_space(xdr, 4 + fh->size);
2837 	xdr_encode_opaque(p, fh->data, fh->size);
2838 	/* ff_io_latency4 read */
2839 	spin_lock(&dss_info->mirror->lock);
2840 	ff_layout_encode_io_latency(xdr,
2841 				    &dss_info->read_stat.io_stat);
2842 	/* ff_io_latency4 write */
2843 	ff_layout_encode_io_latency(xdr,
2844 				    &dss_info->write_stat.io_stat);
2845 	spin_unlock(&dss_info->mirror->lock);
2846 	/* nfstime4 */
2847 	ff_layout_encode_nfstime(xdr,
2848 				 ktime_sub(ktime_get(),
2849 					   dss_info->start_time));
2850 	/* bool */
2851 	p = xdr_reserve_space(xdr, 4);
2852 	*p = cpu_to_be32(false);
2853 }
2854 
2855 static void
2856 ff_layout_encode_layoutstats(struct xdr_stream *xdr, const void *args,
2857 			     const struct nfs4_xdr_opaque_data *opaque)
2858 {
2859 	struct nfs42_layoutstat_devinfo *devinfo = container_of(opaque,
2860 			struct nfs42_layoutstat_devinfo, ld_private);
2861 	__be32 *start;
2862 
2863 	/* layoutupdate length */
2864 	start = xdr_reserve_space(xdr, 4);
2865 	ff_layout_encode_ff_layoutupdate(xdr, devinfo, opaque->data);
2866 
2867 	*start = cpu_to_be32((xdr->p - start - 1) * 4);
2868 }
2869 
2870 static void
2871 ff_layout_free_layoutstats(struct nfs4_xdr_opaque_data *opaque)
2872 {
2873 	struct nfs4_ff_layout_ds_stripe *dss_info = opaque->data;
2874 	struct nfs4_ff_layout_mirror *mirror = dss_info->mirror;
2875 
2876 	ff_layout_put_mirror(mirror);
2877 }
2878 
2879 static const struct nfs4_xdr_opaque_ops layoutstat_ops = {
2880 	.encode = ff_layout_encode_layoutstats,
2881 	.free	= ff_layout_free_layoutstats,
2882 };
2883 
2884 static int
2885 ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
2886 			       struct nfs42_layoutstat_devinfo *devinfo,
2887 			       int dev_limit, enum nfs4_ff_op_type type)
2888 {
2889 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
2890 	struct nfs4_ff_layout_mirror *mirror;
2891 	struct nfs4_ff_layout_ds_stripe *dss_info;
2892 	struct nfs4_deviceid_node *dev;
2893 	int i = 0, dss_id;
2894 
2895 	list_for_each_entry(mirror, &ff_layout->mirrors, mirrors) {
2896 		for (dss_id = 0; dss_id < mirror->dss_count; ++dss_id) {
2897 			dss_info = &mirror->dss[dss_id];
2898 			if (i >= dev_limit)
2899 				break;
2900 			if (IS_ERR_OR_NULL(dss_info->mirror_ds))
2901 				continue;
2902 			if (!test_and_clear_bit(NFS4_FF_MIRROR_STAT_AVAIL,
2903 						&mirror->flags) &&
2904 			    type != NFS4_FF_OP_LAYOUTRETURN)
2905 				continue;
2906 			/* mirror refcount put in cleanup_layoutstats */
2907 			if (!refcount_inc_not_zero(&mirror->ref))
2908 				continue;
2909 			dev = &dss_info->mirror_ds->id_node;
2910 			memcpy(&devinfo->dev_id,
2911 			       &dev->deviceid,
2912 			       NFS4_DEVICEID4_SIZE);
2913 			devinfo->offset = 0;
2914 			devinfo->length = NFS4_MAX_UINT64;
2915 			spin_lock(&mirror->lock);
2916 			devinfo->read_count =
2917 			    dss_info->read_stat.io_stat.ops_completed;
2918 			devinfo->read_bytes =
2919 			    dss_info->read_stat.io_stat.bytes_completed;
2920 			devinfo->write_count =
2921 			    dss_info->write_stat.io_stat.ops_completed;
2922 			devinfo->write_bytes =
2923 			    dss_info->write_stat.io_stat.bytes_completed;
2924 			spin_unlock(&mirror->lock);
2925 			devinfo->layout_type = LAYOUT_FLEX_FILES;
2926 			devinfo->ld_private.ops = &layoutstat_ops;
2927 			devinfo->ld_private.data = &mirror->dss[dss_id];
2928 
2929 			devinfo++;
2930 			i++;
2931 		}
2932 	}
2933 	return i;
2934 }
2935 
2936 static int ff_layout_prepare_layoutstats(struct nfs42_layoutstat_args *args)
2937 {
2938 	struct pnfs_layout_hdr *lo;
2939 	struct nfs4_flexfile_layout *ff_layout;
2940 	const int dev_count = PNFS_LAYOUTSTATS_MAXDEV;
2941 
2942 	/* For now, send at most PNFS_LAYOUTSTATS_MAXDEV statistics */
2943 	args->devinfo = kmalloc_objs(*args->devinfo, dev_count,
2944 				     nfs_io_gfp_mask());
2945 	if (!args->devinfo)
2946 		return -ENOMEM;
2947 
2948 	spin_lock(&args->inode->i_lock);
2949 	lo = NFS_I(args->inode)->layout;
2950 	if (lo && pnfs_layout_is_valid(lo)) {
2951 		ff_layout = FF_LAYOUT_FROM_HDR(lo);
2952 		args->num_dev = ff_layout_mirror_prepare_stats(
2953 			&ff_layout->generic_hdr, &args->devinfo[0], dev_count,
2954 			NFS4_FF_OP_LAYOUTSTATS);
2955 	} else
2956 		args->num_dev = 0;
2957 	spin_unlock(&args->inode->i_lock);
2958 	if (!args->num_dev) {
2959 		kfree(args->devinfo);
2960 		args->devinfo = NULL;
2961 		return -ENOENT;
2962 	}
2963 
2964 	return 0;
2965 }
2966 
2967 static int
2968 ff_layout_set_layoutdriver(struct nfs_server *server,
2969 		const struct nfs_fh *dummy)
2970 {
2971 #if IS_ENABLED(CONFIG_NFS_V4_2)
2972 	server->caps |= NFS_CAP_LAYOUTSTATS | NFS_CAP_REBOOT_LAYOUTRETURN;
2973 #endif
2974 	return 0;
2975 }
2976 
2977 static const struct pnfs_commit_ops ff_layout_commit_ops = {
2978 	.setup_ds_info		= ff_layout_setup_ds_info,
2979 	.release_ds_info	= ff_layout_release_ds_info,
2980 	.mark_request_commit	= pnfs_layout_mark_request_commit,
2981 	.clear_request_commit	= pnfs_generic_clear_request_commit,
2982 	.scan_commit_lists	= pnfs_generic_scan_commit_lists,
2983 	.recover_commit_reqs	= pnfs_generic_recover_commit_reqs,
2984 	.commit_pagelist	= ff_layout_commit_pagelist,
2985 };
2986 
2987 static struct pnfs_layoutdriver_type flexfilelayout_type = {
2988 	.id			= LAYOUT_FLEX_FILES,
2989 	.name			= "LAYOUT_FLEX_FILES",
2990 	.owner			= THIS_MODULE,
2991 	.flags			= PNFS_LAYOUTGET_ON_OPEN,
2992 	.max_layoutget_response	= 4096, /* 1 page or so... */
2993 	.set_layoutdriver	= ff_layout_set_layoutdriver,
2994 	.alloc_layout_hdr	= ff_layout_alloc_layout_hdr,
2995 	.free_layout_hdr	= ff_layout_free_layout_hdr,
2996 	.alloc_lseg		= ff_layout_alloc_lseg,
2997 	.free_lseg		= ff_layout_free_lseg,
2998 	.add_lseg		= ff_layout_add_lseg,
2999 	.pg_read_ops		= &ff_layout_pg_read_ops,
3000 	.pg_write_ops		= &ff_layout_pg_write_ops,
3001 	.get_ds_info		= ff_layout_get_ds_info,
3002 	.free_deviceid_node	= ff_layout_free_deviceid_node,
3003 	.read_pagelist		= ff_layout_read_pagelist,
3004 	.write_pagelist		= ff_layout_write_pagelist,
3005 	.alloc_deviceid_node    = ff_layout_alloc_deviceid_node,
3006 	.prepare_layoutreturn   = ff_layout_prepare_layoutreturn,
3007 	.sync			= pnfs_nfs_generic_sync,
3008 	.prepare_layoutstats	= ff_layout_prepare_layoutstats,
3009 	.cancel_io		= ff_layout_cancel_io,
3010 };
3011 
3012 static int __init nfs4flexfilelayout_init(void)
3013 {
3014 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Registering...\n",
3015 	       __func__);
3016 	return pnfs_register_layoutdriver(&flexfilelayout_type);
3017 }
3018 
3019 static void __exit nfs4flexfilelayout_exit(void)
3020 {
3021 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Unregistering...\n",
3022 	       __func__);
3023 	pnfs_unregister_layoutdriver(&flexfilelayout_type);
3024 }
3025 
3026 MODULE_ALIAS("nfs-layouttype4-4");
3027 
3028 MODULE_LICENSE("GPL");
3029 MODULE_DESCRIPTION("The NFSv4 flexfile layout driver");
3030 
3031 module_init(nfs4flexfilelayout_init);
3032 module_exit(nfs4flexfilelayout_exit);
3033 
3034 module_param(io_maxretrans, ushort, 0644);
3035 MODULE_PARM_DESC(io_maxretrans, "The  number of times the NFSv4.1 client "
3036 			"retries an I/O request before returning an error. ");
3037