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