1 /*
2  * Module for pnfs flexfile layout driver.
3  *
4  * Copyright (c) 2014, Primary Data, Inc. All rights reserved.
5  *
6  * Tao Peng <bergwolf@primarydata.com>
7  */
8 
9 #include <linux/nfs_fs.h>
10 #include <linux/nfs_page.h>
11 #include <linux/module.h>
12 
13 #include <linux/sunrpc/metrics.h>
14 
15 #include "flexfilelayout.h"
16 #include "../nfs4session.h"
17 #include "../nfs4idmap.h"
18 #include "../internal.h"
19 #include "../delegation.h"
20 #include "../nfs4trace.h"
21 #include "../iostat.h"
22 #include "../nfs.h"
23 #include "../nfs42.h"
24 
25 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
26 
27 #define FF_LAYOUT_POLL_RETRY_MAX     (15*HZ)
28 #define FF_LAYOUTRETURN_MAXERR 20
29 
30 
31 static struct group_info	*ff_zero_group;
32 
33 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
34 		struct nfs_pgio_header *hdr);
35 static int ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
36 			       struct nfs42_layoutstat_devinfo *devinfo,
37 			       int dev_limit);
38 static void ff_layout_encode_ff_layoutupdate(struct xdr_stream *xdr,
39 			      const struct nfs42_layoutstat_devinfo *devinfo,
40 			      struct nfs4_ff_layout_mirror *mirror);
41 
42 static struct pnfs_layout_hdr *
43 ff_layout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags)
44 {
45 	struct nfs4_flexfile_layout *ffl;
46 
47 	ffl = kzalloc(sizeof(*ffl), gfp_flags);
48 	if (ffl) {
49 		INIT_LIST_HEAD(&ffl->error_list);
50 		INIT_LIST_HEAD(&ffl->mirrors);
51 		ffl->last_report_time = ktime_get();
52 		return &ffl->generic_hdr;
53 	} else
54 		return NULL;
55 }
56 
57 static void
58 ff_layout_free_layout_hdr(struct pnfs_layout_hdr *lo)
59 {
60 	struct nfs4_ff_layout_ds_err *err, *n;
61 
62 	list_for_each_entry_safe(err, n, &FF_LAYOUT_FROM_HDR(lo)->error_list,
63 				 list) {
64 		list_del(&err->list);
65 		kfree(err);
66 	}
67 	kfree(FF_LAYOUT_FROM_HDR(lo));
68 }
69 
70 static int decode_pnfs_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
71 {
72 	__be32 *p;
73 
74 	p = xdr_inline_decode(xdr, NFS4_STATEID_SIZE);
75 	if (unlikely(p == NULL))
76 		return -ENOBUFS;
77 	stateid->type = NFS4_PNFS_DS_STATEID_TYPE;
78 	memcpy(stateid->data, p, NFS4_STATEID_SIZE);
79 	dprintk("%s: stateid id= [%x%x%x%x]\n", __func__,
80 		p[0], p[1], p[2], p[3]);
81 	return 0;
82 }
83 
84 static int decode_deviceid(struct xdr_stream *xdr, struct nfs4_deviceid *devid)
85 {
86 	__be32 *p;
87 
88 	p = xdr_inline_decode(xdr, NFS4_DEVICEID4_SIZE);
89 	if (unlikely(!p))
90 		return -ENOBUFS;
91 	memcpy(devid, p, NFS4_DEVICEID4_SIZE);
92 	nfs4_print_deviceid(devid);
93 	return 0;
94 }
95 
96 static int decode_nfs_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
97 {
98 	__be32 *p;
99 
100 	p = xdr_inline_decode(xdr, 4);
101 	if (unlikely(!p))
102 		return -ENOBUFS;
103 	fh->size = be32_to_cpup(p++);
104 	if (fh->size > sizeof(struct nfs_fh)) {
105 		printk(KERN_ERR "NFS flexfiles: Too big fh received %d\n",
106 		       fh->size);
107 		return -EOVERFLOW;
108 	}
109 	/* fh.data */
110 	p = xdr_inline_decode(xdr, fh->size);
111 	if (unlikely(!p))
112 		return -ENOBUFS;
113 	memcpy(&fh->data, p, fh->size);
114 	dprintk("%s: fh len %d\n", __func__, fh->size);
115 
116 	return 0;
117 }
118 
119 /*
120  * Currently only stringified uids and gids are accepted.
121  * I.e., kerberos is not supported to the DSes, so no pricipals.
122  *
123  * That means that one common function will suffice, but when
124  * principals are added, this should be split to accomodate
125  * calls to both nfs_map_name_to_uid() and nfs_map_group_to_gid().
126  */
127 static int
128 decode_name(struct xdr_stream *xdr, u32 *id)
129 {
130 	__be32 *p;
131 	int len;
132 
133 	/* opaque_length(4)*/
134 	p = xdr_inline_decode(xdr, 4);
135 	if (unlikely(!p))
136 		return -ENOBUFS;
137 	len = be32_to_cpup(p++);
138 	if (len < 0)
139 		return -EINVAL;
140 
141 	dprintk("%s: len %u\n", __func__, len);
142 
143 	/* opaque body */
144 	p = xdr_inline_decode(xdr, len);
145 	if (unlikely(!p))
146 		return -ENOBUFS;
147 
148 	if (!nfs_map_string_to_numeric((char *)p, len, id))
149 		return -EINVAL;
150 
151 	return 0;
152 }
153 
154 static bool ff_mirror_match_fh(const struct nfs4_ff_layout_mirror *m1,
155 		const struct nfs4_ff_layout_mirror *m2)
156 {
157 	int i, j;
158 
159 	if (m1->fh_versions_cnt != m2->fh_versions_cnt)
160 		return false;
161 	for (i = 0; i < m1->fh_versions_cnt; i++) {
162 		bool found_fh = false;
163 		for (j = 0; j < m2->fh_versions_cnt; j++) {
164 			if (nfs_compare_fh(&m1->fh_versions[i],
165 					&m2->fh_versions[j]) == 0) {
166 				found_fh = true;
167 				break;
168 			}
169 		}
170 		if (!found_fh)
171 			return false;
172 	}
173 	return true;
174 }
175 
176 static struct nfs4_ff_layout_mirror *
177 ff_layout_add_mirror(struct pnfs_layout_hdr *lo,
178 		struct nfs4_ff_layout_mirror *mirror)
179 {
180 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
181 	struct nfs4_ff_layout_mirror *pos;
182 	struct inode *inode = lo->plh_inode;
183 
184 	spin_lock(&inode->i_lock);
185 	list_for_each_entry(pos, &ff_layout->mirrors, mirrors) {
186 		if (memcmp(&mirror->devid, &pos->devid, sizeof(pos->devid)) != 0)
187 			continue;
188 		if (!ff_mirror_match_fh(mirror, pos))
189 			continue;
190 		if (atomic_inc_not_zero(&pos->ref)) {
191 			spin_unlock(&inode->i_lock);
192 			return pos;
193 		}
194 	}
195 	list_add(&mirror->mirrors, &ff_layout->mirrors);
196 	mirror->layout = lo;
197 	spin_unlock(&inode->i_lock);
198 	return mirror;
199 }
200 
201 static void
202 ff_layout_remove_mirror(struct nfs4_ff_layout_mirror *mirror)
203 {
204 	struct inode *inode;
205 	if (mirror->layout == NULL)
206 		return;
207 	inode = mirror->layout->plh_inode;
208 	spin_lock(&inode->i_lock);
209 	list_del(&mirror->mirrors);
210 	spin_unlock(&inode->i_lock);
211 	mirror->layout = NULL;
212 }
213 
214 static struct nfs4_ff_layout_mirror *ff_layout_alloc_mirror(gfp_t gfp_flags)
215 {
216 	struct nfs4_ff_layout_mirror *mirror;
217 
218 	mirror = kzalloc(sizeof(*mirror), gfp_flags);
219 	if (mirror != NULL) {
220 		spin_lock_init(&mirror->lock);
221 		atomic_set(&mirror->ref, 1);
222 		INIT_LIST_HEAD(&mirror->mirrors);
223 	}
224 	return mirror;
225 }
226 
227 static void ff_layout_free_mirror(struct nfs4_ff_layout_mirror *mirror)
228 {
229 	struct rpc_cred	*cred;
230 
231 	ff_layout_remove_mirror(mirror);
232 	kfree(mirror->fh_versions);
233 	cred = rcu_access_pointer(mirror->ro_cred);
234 	if (cred)
235 		put_rpccred(cred);
236 	cred = rcu_access_pointer(mirror->rw_cred);
237 	if (cred)
238 		put_rpccred(cred);
239 	nfs4_ff_layout_put_deviceid(mirror->mirror_ds);
240 	kfree(mirror);
241 }
242 
243 static void ff_layout_put_mirror(struct nfs4_ff_layout_mirror *mirror)
244 {
245 	if (mirror != NULL && atomic_dec_and_test(&mirror->ref))
246 		ff_layout_free_mirror(mirror);
247 }
248 
249 static void ff_layout_free_mirror_array(struct nfs4_ff_layout_segment *fls)
250 {
251 	int i;
252 
253 	if (fls->mirror_array) {
254 		for (i = 0; i < fls->mirror_array_cnt; i++) {
255 			/* normally mirror_ds is freed in
256 			 * .free_deviceid_node but we still do it here
257 			 * for .alloc_lseg error path */
258 			ff_layout_put_mirror(fls->mirror_array[i]);
259 		}
260 		kfree(fls->mirror_array);
261 		fls->mirror_array = NULL;
262 	}
263 }
264 
265 static int ff_layout_check_layout(struct nfs4_layoutget_res *lgr)
266 {
267 	int ret = 0;
268 
269 	dprintk("--> %s\n", __func__);
270 
271 	/* FIXME: remove this check when layout segment support is added */
272 	if (lgr->range.offset != 0 ||
273 	    lgr->range.length != NFS4_MAX_UINT64) {
274 		dprintk("%s Only whole file layouts supported. Use MDS i/o\n",
275 			__func__);
276 		ret = -EINVAL;
277 	}
278 
279 	dprintk("--> %s returns %d\n", __func__, ret);
280 	return ret;
281 }
282 
283 static void _ff_layout_free_lseg(struct nfs4_ff_layout_segment *fls)
284 {
285 	if (fls) {
286 		ff_layout_free_mirror_array(fls);
287 		kfree(fls);
288 	}
289 }
290 
291 static bool
292 ff_lseg_range_is_after(const struct pnfs_layout_range *l1,
293 		const struct pnfs_layout_range *l2)
294 {
295 	u64 end1, end2;
296 
297 	if (l1->iomode != l2->iomode)
298 		return l1->iomode != IOMODE_READ;
299 	end1 = pnfs_calc_offset_end(l1->offset, l1->length);
300 	end2 = pnfs_calc_offset_end(l2->offset, l2->length);
301 	if (end1 < l2->offset)
302 		return false;
303 	if (end2 < l1->offset)
304 		return true;
305 	return l2->offset <= l1->offset;
306 }
307 
308 static bool
309 ff_lseg_merge(struct pnfs_layout_segment *new,
310 		struct pnfs_layout_segment *old)
311 {
312 	u64 new_end, old_end;
313 
314 	if (test_bit(NFS_LSEG_LAYOUTRETURN, &old->pls_flags))
315 		return false;
316 	if (new->pls_range.iomode != old->pls_range.iomode)
317 		return false;
318 	old_end = pnfs_calc_offset_end(old->pls_range.offset,
319 			old->pls_range.length);
320 	if (old_end < new->pls_range.offset)
321 		return false;
322 	new_end = pnfs_calc_offset_end(new->pls_range.offset,
323 			new->pls_range.length);
324 	if (new_end < old->pls_range.offset)
325 		return false;
326 
327 	/* Mergeable: copy info from 'old' to 'new' */
328 	if (new_end < old_end)
329 		new_end = old_end;
330 	if (new->pls_range.offset < old->pls_range.offset)
331 		new->pls_range.offset = old->pls_range.offset;
332 	new->pls_range.length = pnfs_calc_offset_length(new->pls_range.offset,
333 			new_end);
334 	if (test_bit(NFS_LSEG_ROC, &old->pls_flags))
335 		set_bit(NFS_LSEG_ROC, &new->pls_flags);
336 	return true;
337 }
338 
339 static void
340 ff_layout_add_lseg(struct pnfs_layout_hdr *lo,
341 		struct pnfs_layout_segment *lseg,
342 		struct list_head *free_me)
343 {
344 	pnfs_generic_layout_insert_lseg(lo, lseg,
345 			ff_lseg_range_is_after,
346 			ff_lseg_merge,
347 			free_me);
348 }
349 
350 static void ff_layout_sort_mirrors(struct nfs4_ff_layout_segment *fls)
351 {
352 	int i, j;
353 
354 	for (i = 0; i < fls->mirror_array_cnt - 1; i++) {
355 		for (j = i + 1; j < fls->mirror_array_cnt; j++)
356 			if (fls->mirror_array[i]->efficiency <
357 			    fls->mirror_array[j]->efficiency)
358 				swap(fls->mirror_array[i],
359 				     fls->mirror_array[j]);
360 	}
361 }
362 
363 static struct pnfs_layout_segment *
364 ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh,
365 		     struct nfs4_layoutget_res *lgr,
366 		     gfp_t gfp_flags)
367 {
368 	struct pnfs_layout_segment *ret;
369 	struct nfs4_ff_layout_segment *fls = NULL;
370 	struct xdr_stream stream;
371 	struct xdr_buf buf;
372 	struct page *scratch;
373 	u64 stripe_unit;
374 	u32 mirror_array_cnt;
375 	__be32 *p;
376 	int i, rc;
377 
378 	dprintk("--> %s\n", __func__);
379 	scratch = alloc_page(gfp_flags);
380 	if (!scratch)
381 		return ERR_PTR(-ENOMEM);
382 
383 	xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages,
384 			      lgr->layoutp->len);
385 	xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
386 
387 	/* stripe unit and mirror_array_cnt */
388 	rc = -EIO;
389 	p = xdr_inline_decode(&stream, 8 + 4);
390 	if (!p)
391 		goto out_err_free;
392 
393 	p = xdr_decode_hyper(p, &stripe_unit);
394 	mirror_array_cnt = be32_to_cpup(p++);
395 	dprintk("%s: stripe_unit=%llu mirror_array_cnt=%u\n", __func__,
396 		stripe_unit, mirror_array_cnt);
397 
398 	if (mirror_array_cnt > NFS4_FLEXFILE_LAYOUT_MAX_MIRROR_CNT ||
399 	    mirror_array_cnt == 0)
400 		goto out_err_free;
401 
402 	rc = -ENOMEM;
403 	fls = kzalloc(sizeof(*fls), gfp_flags);
404 	if (!fls)
405 		goto out_err_free;
406 
407 	fls->mirror_array_cnt = mirror_array_cnt;
408 	fls->stripe_unit = stripe_unit;
409 	fls->mirror_array = kcalloc(fls->mirror_array_cnt,
410 				    sizeof(fls->mirror_array[0]), gfp_flags);
411 	if (fls->mirror_array == NULL)
412 		goto out_err_free;
413 
414 	for (i = 0; i < fls->mirror_array_cnt; i++) {
415 		struct nfs4_ff_layout_mirror *mirror;
416 		struct auth_cred acred = { .group_info = ff_zero_group };
417 		struct rpc_cred	__rcu *cred;
418 		u32 ds_count, fh_count, id;
419 		int j;
420 
421 		rc = -EIO;
422 		p = xdr_inline_decode(&stream, 4);
423 		if (!p)
424 			goto out_err_free;
425 		ds_count = be32_to_cpup(p);
426 
427 		/* FIXME: allow for striping? */
428 		if (ds_count != 1)
429 			goto out_err_free;
430 
431 		fls->mirror_array[i] = ff_layout_alloc_mirror(gfp_flags);
432 		if (fls->mirror_array[i] == NULL) {
433 			rc = -ENOMEM;
434 			goto out_err_free;
435 		}
436 
437 		fls->mirror_array[i]->ds_count = ds_count;
438 
439 		/* deviceid */
440 		rc = decode_deviceid(&stream, &fls->mirror_array[i]->devid);
441 		if (rc)
442 			goto out_err_free;
443 
444 		/* efficiency */
445 		rc = -EIO;
446 		p = xdr_inline_decode(&stream, 4);
447 		if (!p)
448 			goto out_err_free;
449 		fls->mirror_array[i]->efficiency = be32_to_cpup(p);
450 
451 		/* stateid */
452 		rc = decode_pnfs_stateid(&stream, &fls->mirror_array[i]->stateid);
453 		if (rc)
454 			goto out_err_free;
455 
456 		/* fh */
457 		p = xdr_inline_decode(&stream, 4);
458 		if (!p)
459 			goto out_err_free;
460 		fh_count = be32_to_cpup(p);
461 
462 		fls->mirror_array[i]->fh_versions =
463 			kzalloc(fh_count * sizeof(struct nfs_fh),
464 				gfp_flags);
465 		if (fls->mirror_array[i]->fh_versions == NULL) {
466 			rc = -ENOMEM;
467 			goto out_err_free;
468 		}
469 
470 		for (j = 0; j < fh_count; j++) {
471 			rc = decode_nfs_fh(&stream,
472 					   &fls->mirror_array[i]->fh_versions[j]);
473 			if (rc)
474 				goto out_err_free;
475 		}
476 
477 		fls->mirror_array[i]->fh_versions_cnt = fh_count;
478 
479 		/* user */
480 		rc = decode_name(&stream, &id);
481 		if (rc)
482 			goto out_err_free;
483 
484 		acred.uid = make_kuid(&init_user_ns, id);
485 
486 		/* group */
487 		rc = decode_name(&stream, &id);
488 		if (rc)
489 			goto out_err_free;
490 
491 		acred.gid = make_kgid(&init_user_ns, id);
492 
493 		/* find the cred for it */
494 		rcu_assign_pointer(cred, rpc_lookup_generic_cred(&acred, 0, gfp_flags));
495 		if (IS_ERR(cred)) {
496 			rc = PTR_ERR(cred);
497 			goto out_err_free;
498 		}
499 
500 		if (lgr->range.iomode == IOMODE_READ)
501 			rcu_assign_pointer(fls->mirror_array[i]->ro_cred, cred);
502 		else
503 			rcu_assign_pointer(fls->mirror_array[i]->rw_cred, cred);
504 
505 		mirror = ff_layout_add_mirror(lh, fls->mirror_array[i]);
506 		if (mirror != fls->mirror_array[i]) {
507 			/* swap cred ptrs so free_mirror will clean up old */
508 			if (lgr->range.iomode == IOMODE_READ) {
509 				cred = xchg(&mirror->ro_cred, cred);
510 				rcu_assign_pointer(fls->mirror_array[i]->ro_cred, cred);
511 			} else {
512 				cred = xchg(&mirror->rw_cred, cred);
513 				rcu_assign_pointer(fls->mirror_array[i]->rw_cred, cred);
514 			}
515 			ff_layout_free_mirror(fls->mirror_array[i]);
516 			fls->mirror_array[i] = mirror;
517 		}
518 
519 		dprintk("%s: iomode %s uid %u gid %u\n", __func__,
520 			lgr->range.iomode == IOMODE_READ ? "READ" : "RW",
521 			from_kuid(&init_user_ns, acred.uid),
522 			from_kgid(&init_user_ns, acred.gid));
523 	}
524 
525 	p = xdr_inline_decode(&stream, 4);
526 	if (!p)
527 		goto out_sort_mirrors;
528 	fls->flags = be32_to_cpup(p);
529 
530 	p = xdr_inline_decode(&stream, 4);
531 	if (!p)
532 		goto out_sort_mirrors;
533 	for (i=0; i < fls->mirror_array_cnt; i++)
534 		fls->mirror_array[i]->report_interval = be32_to_cpup(p);
535 
536 out_sort_mirrors:
537 	ff_layout_sort_mirrors(fls);
538 	rc = ff_layout_check_layout(lgr);
539 	if (rc)
540 		goto out_err_free;
541 	ret = &fls->generic_hdr;
542 	dprintk("<-- %s (success)\n", __func__);
543 out_free_page:
544 	__free_page(scratch);
545 	return ret;
546 out_err_free:
547 	_ff_layout_free_lseg(fls);
548 	ret = ERR_PTR(rc);
549 	dprintk("<-- %s (%d)\n", __func__, rc);
550 	goto out_free_page;
551 }
552 
553 static bool ff_layout_has_rw_segments(struct pnfs_layout_hdr *layout)
554 {
555 	struct pnfs_layout_segment *lseg;
556 
557 	list_for_each_entry(lseg, &layout->plh_segs, pls_list)
558 		if (lseg->pls_range.iomode == IOMODE_RW)
559 			return true;
560 
561 	return false;
562 }
563 
564 static void
565 ff_layout_free_lseg(struct pnfs_layout_segment *lseg)
566 {
567 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
568 
569 	dprintk("--> %s\n", __func__);
570 
571 	if (lseg->pls_range.iomode == IOMODE_RW) {
572 		struct nfs4_flexfile_layout *ffl;
573 		struct inode *inode;
574 
575 		ffl = FF_LAYOUT_FROM_HDR(lseg->pls_layout);
576 		inode = ffl->generic_hdr.plh_inode;
577 		spin_lock(&inode->i_lock);
578 		if (!ff_layout_has_rw_segments(lseg->pls_layout)) {
579 			ffl->commit_info.nbuckets = 0;
580 			kfree(ffl->commit_info.buckets);
581 			ffl->commit_info.buckets = NULL;
582 		}
583 		spin_unlock(&inode->i_lock);
584 	}
585 	_ff_layout_free_lseg(fls);
586 }
587 
588 /* Return 1 until we have multiple lsegs support */
589 static int
590 ff_layout_get_lseg_count(struct nfs4_ff_layout_segment *fls)
591 {
592 	return 1;
593 }
594 
595 static void
596 nfs4_ff_start_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
597 {
598 	/* first IO request? */
599 	if (atomic_inc_return(&timer->n_ops) == 1) {
600 		timer->start_time = now;
601 	}
602 }
603 
604 static ktime_t
605 nfs4_ff_end_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
606 {
607 	ktime_t start;
608 
609 	if (atomic_dec_return(&timer->n_ops) < 0)
610 		WARN_ON_ONCE(1);
611 
612 	start = timer->start_time;
613 	timer->start_time = now;
614 	return ktime_sub(now, start);
615 }
616 
617 static bool
618 nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_mirror *mirror,
619 			    struct nfs4_ff_layoutstat *layoutstat,
620 			    ktime_t now)
621 {
622 	s64 report_interval = FF_LAYOUTSTATS_REPORT_INTERVAL;
623 	struct nfs4_flexfile_layout *ffl = FF_LAYOUT_FROM_HDR(mirror->layout);
624 
625 	nfs4_ff_start_busy_timer(&layoutstat->busy_timer, now);
626 	if (!mirror->start_time)
627 		mirror->start_time = now;
628 	if (mirror->report_interval != 0)
629 		report_interval = (s64)mirror->report_interval * 1000LL;
630 	else if (layoutstats_timer != 0)
631 		report_interval = (s64)layoutstats_timer * 1000LL;
632 	if (ktime_to_ms(ktime_sub(now, ffl->last_report_time)) >=
633 			report_interval) {
634 		ffl->last_report_time = now;
635 		return true;
636 	}
637 
638 	return false;
639 }
640 
641 static void
642 nfs4_ff_layout_stat_io_update_requested(struct nfs4_ff_layoutstat *layoutstat,
643 		__u64 requested)
644 {
645 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
646 
647 	iostat->ops_requested++;
648 	iostat->bytes_requested += requested;
649 }
650 
651 static void
652 nfs4_ff_layout_stat_io_update_completed(struct nfs4_ff_layoutstat *layoutstat,
653 		__u64 requested,
654 		__u64 completed,
655 		ktime_t time_completed,
656 		ktime_t time_started)
657 {
658 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
659 	ktime_t completion_time = ktime_sub(time_completed, time_started);
660 	ktime_t timer;
661 
662 	iostat->ops_completed++;
663 	iostat->bytes_completed += completed;
664 	iostat->bytes_not_delivered += requested - completed;
665 
666 	timer = nfs4_ff_end_busy_timer(&layoutstat->busy_timer, time_completed);
667 	iostat->total_busy_time =
668 			ktime_add(iostat->total_busy_time, timer);
669 	iostat->aggregate_completion_time =
670 			ktime_add(iostat->aggregate_completion_time,
671 					completion_time);
672 }
673 
674 static void
675 nfs4_ff_layout_stat_io_start_read(struct inode *inode,
676 		struct nfs4_ff_layout_mirror *mirror,
677 		__u64 requested, ktime_t now)
678 {
679 	bool report;
680 
681 	spin_lock(&mirror->lock);
682 	report = nfs4_ff_layoutstat_start_io(mirror, &mirror->read_stat, now);
683 	nfs4_ff_layout_stat_io_update_requested(&mirror->read_stat, requested);
684 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
685 	spin_unlock(&mirror->lock);
686 
687 	if (report)
688 		pnfs_report_layoutstat(inode, GFP_KERNEL);
689 }
690 
691 static void
692 nfs4_ff_layout_stat_io_end_read(struct rpc_task *task,
693 		struct nfs4_ff_layout_mirror *mirror,
694 		__u64 requested,
695 		__u64 completed)
696 {
697 	spin_lock(&mirror->lock);
698 	nfs4_ff_layout_stat_io_update_completed(&mirror->read_stat,
699 			requested, completed,
700 			ktime_get(), task->tk_start);
701 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
702 	spin_unlock(&mirror->lock);
703 }
704 
705 static void
706 nfs4_ff_layout_stat_io_start_write(struct inode *inode,
707 		struct nfs4_ff_layout_mirror *mirror,
708 		__u64 requested, ktime_t now)
709 {
710 	bool report;
711 
712 	spin_lock(&mirror->lock);
713 	report = nfs4_ff_layoutstat_start_io(mirror , &mirror->write_stat, now);
714 	nfs4_ff_layout_stat_io_update_requested(&mirror->write_stat, requested);
715 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
716 	spin_unlock(&mirror->lock);
717 
718 	if (report)
719 		pnfs_report_layoutstat(inode, GFP_NOIO);
720 }
721 
722 static void
723 nfs4_ff_layout_stat_io_end_write(struct rpc_task *task,
724 		struct nfs4_ff_layout_mirror *mirror,
725 		__u64 requested,
726 		__u64 completed,
727 		enum nfs3_stable_how committed)
728 {
729 	if (committed == NFS_UNSTABLE)
730 		requested = completed = 0;
731 
732 	spin_lock(&mirror->lock);
733 	nfs4_ff_layout_stat_io_update_completed(&mirror->write_stat,
734 			requested, completed, ktime_get(), task->tk_start);
735 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
736 	spin_unlock(&mirror->lock);
737 }
738 
739 static int
740 ff_layout_alloc_commit_info(struct pnfs_layout_segment *lseg,
741 			    struct nfs_commit_info *cinfo,
742 			    gfp_t gfp_flags)
743 {
744 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
745 	struct pnfs_commit_bucket *buckets;
746 	int size;
747 
748 	if (cinfo->ds->nbuckets != 0) {
749 		/* This assumes there is only one RW lseg per file.
750 		 * To support multiple lseg per file, we need to
751 		 * change struct pnfs_commit_bucket to allow dynamic
752 		 * increasing nbuckets.
753 		 */
754 		return 0;
755 	}
756 
757 	size = ff_layout_get_lseg_count(fls) * FF_LAYOUT_MIRROR_COUNT(lseg);
758 
759 	buckets = kcalloc(size, sizeof(struct pnfs_commit_bucket),
760 			  gfp_flags);
761 	if (!buckets)
762 		return -ENOMEM;
763 	else {
764 		int i;
765 
766 		spin_lock(&cinfo->inode->i_lock);
767 		if (cinfo->ds->nbuckets != 0)
768 			kfree(buckets);
769 		else {
770 			cinfo->ds->buckets = buckets;
771 			cinfo->ds->nbuckets = size;
772 			for (i = 0; i < size; i++) {
773 				INIT_LIST_HEAD(&buckets[i].written);
774 				INIT_LIST_HEAD(&buckets[i].committing);
775 				/* mark direct verifier as unset */
776 				buckets[i].direct_verf.committed =
777 					NFS_INVALID_STABLE_HOW;
778 			}
779 		}
780 		spin_unlock(&cinfo->inode->i_lock);
781 		return 0;
782 	}
783 }
784 
785 static struct nfs4_pnfs_ds *
786 ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg,
787 				  int start_idx,
788 				  int *best_idx)
789 {
790 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
791 	struct nfs4_pnfs_ds *ds;
792 	bool fail_return = false;
793 	int idx;
794 
795 	/* mirrors are sorted by efficiency */
796 	for (idx = start_idx; idx < fls->mirror_array_cnt; idx++) {
797 		if (idx+1 == fls->mirror_array_cnt)
798 			fail_return = true;
799 		ds = nfs4_ff_layout_prepare_ds(lseg, idx, fail_return);
800 		if (ds) {
801 			*best_idx = idx;
802 			return ds;
803 		}
804 	}
805 
806 	return NULL;
807 }
808 
809 static void
810 ff_layout_pg_get_read(struct nfs_pageio_descriptor *pgio,
811 		      struct nfs_page *req,
812 		      bool strict_iomode)
813 {
814 retry_strict:
815 	pnfs_put_lseg(pgio->pg_lseg);
816 	pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
817 					   req->wb_context,
818 					   0,
819 					   NFS4_MAX_UINT64,
820 					   IOMODE_READ,
821 					   strict_iomode,
822 					   GFP_KERNEL);
823 	if (IS_ERR(pgio->pg_lseg)) {
824 		pgio->pg_error = PTR_ERR(pgio->pg_lseg);
825 		pgio->pg_lseg = NULL;
826 	}
827 
828 	/* If we don't have checking, do get a IOMODE_RW
829 	 * segment, and the server wants to avoid READs
830 	 * there, then retry!
831 	 */
832 	if (pgio->pg_lseg && !strict_iomode &&
833 	    ff_layout_avoid_read_on_rw(pgio->pg_lseg)) {
834 		strict_iomode = true;
835 		goto retry_strict;
836 	}
837 }
838 
839 static void
840 ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
841 			struct nfs_page *req)
842 {
843 	struct nfs_pgio_mirror *pgm;
844 	struct nfs4_ff_layout_mirror *mirror;
845 	struct nfs4_pnfs_ds *ds;
846 	int ds_idx;
847 
848 retry:
849 	/* Use full layout for now */
850 	if (!pgio->pg_lseg)
851 		ff_layout_pg_get_read(pgio, req, false);
852 	else if (ff_layout_avoid_read_on_rw(pgio->pg_lseg))
853 		ff_layout_pg_get_read(pgio, req, true);
854 
855 	/* If no lseg, fall back to read through mds */
856 	if (pgio->pg_lseg == NULL)
857 		goto out_mds;
858 
859 	ds = ff_layout_choose_best_ds_for_read(pgio->pg_lseg, 0, &ds_idx);
860 	if (!ds) {
861 		if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
862 			goto out_mds;
863 		pnfs_put_lseg(pgio->pg_lseg);
864 		pgio->pg_lseg = NULL;
865 		/* Sleep for 1 second before retrying */
866 		ssleep(1);
867 		goto retry;
868 	}
869 
870 	mirror = FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx);
871 
872 	pgio->pg_mirror_idx = ds_idx;
873 
874 	/* read always uses only one mirror - idx 0 for pgio layer */
875 	pgm = &pgio->pg_mirrors[0];
876 	pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].rsize;
877 
878 	return;
879 out_mds:
880 	pnfs_put_lseg(pgio->pg_lseg);
881 	pgio->pg_lseg = NULL;
882 	nfs_pageio_reset_read_mds(pgio);
883 }
884 
885 static void
886 ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
887 			struct nfs_page *req)
888 {
889 	struct nfs4_ff_layout_mirror *mirror;
890 	struct nfs_pgio_mirror *pgm;
891 	struct nfs_commit_info cinfo;
892 	struct nfs4_pnfs_ds *ds;
893 	int i;
894 	int status;
895 
896 retry:
897 	if (!pgio->pg_lseg) {
898 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
899 						   req->wb_context,
900 						   0,
901 						   NFS4_MAX_UINT64,
902 						   IOMODE_RW,
903 						   false,
904 						   GFP_NOFS);
905 		if (IS_ERR(pgio->pg_lseg)) {
906 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
907 			pgio->pg_lseg = NULL;
908 			return;
909 		}
910 	}
911 	/* If no lseg, fall back to write through mds */
912 	if (pgio->pg_lseg == NULL)
913 		goto out_mds;
914 
915 	nfs_init_cinfo(&cinfo, pgio->pg_inode, pgio->pg_dreq);
916 	status = ff_layout_alloc_commit_info(pgio->pg_lseg, &cinfo, GFP_NOFS);
917 	if (status < 0)
918 		goto out_mds;
919 
920 	/* Use a direct mapping of ds_idx to pgio mirror_idx */
921 	if (WARN_ON_ONCE(pgio->pg_mirror_count !=
922 	    FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg)))
923 		goto out_mds;
924 
925 	for (i = 0; i < pgio->pg_mirror_count; i++) {
926 		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, i, true);
927 		if (!ds) {
928 			if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
929 				goto out_mds;
930 			pnfs_put_lseg(pgio->pg_lseg);
931 			pgio->pg_lseg = NULL;
932 			/* Sleep for 1 second before retrying */
933 			ssleep(1);
934 			goto retry;
935 		}
936 		pgm = &pgio->pg_mirrors[i];
937 		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
938 		pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].wsize;
939 	}
940 
941 	return;
942 
943 out_mds:
944 	pnfs_put_lseg(pgio->pg_lseg);
945 	pgio->pg_lseg = NULL;
946 	nfs_pageio_reset_write_mds(pgio);
947 }
948 
949 static unsigned int
950 ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
951 				    struct nfs_page *req)
952 {
953 	if (!pgio->pg_lseg) {
954 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
955 						   req->wb_context,
956 						   0,
957 						   NFS4_MAX_UINT64,
958 						   IOMODE_RW,
959 						   false,
960 						   GFP_NOFS);
961 		if (IS_ERR(pgio->pg_lseg)) {
962 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
963 			pgio->pg_lseg = NULL;
964 			goto out;
965 		}
966 	}
967 	if (pgio->pg_lseg)
968 		return FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg);
969 
970 	/* no lseg means that pnfs is not in use, so no mirroring here */
971 	nfs_pageio_reset_write_mds(pgio);
972 out:
973 	return 1;
974 }
975 
976 static const struct nfs_pageio_ops ff_layout_pg_read_ops = {
977 	.pg_init = ff_layout_pg_init_read,
978 	.pg_test = pnfs_generic_pg_test,
979 	.pg_doio = pnfs_generic_pg_readpages,
980 	.pg_cleanup = pnfs_generic_pg_cleanup,
981 };
982 
983 static const struct nfs_pageio_ops ff_layout_pg_write_ops = {
984 	.pg_init = ff_layout_pg_init_write,
985 	.pg_test = pnfs_generic_pg_test,
986 	.pg_doio = pnfs_generic_pg_writepages,
987 	.pg_get_mirror_count = ff_layout_pg_get_mirror_count_write,
988 	.pg_cleanup = pnfs_generic_pg_cleanup,
989 };
990 
991 static void ff_layout_reset_write(struct nfs_pgio_header *hdr, bool retry_pnfs)
992 {
993 	struct rpc_task *task = &hdr->task;
994 
995 	pnfs_layoutcommit_inode(hdr->inode, false);
996 
997 	if (retry_pnfs) {
998 		dprintk("%s Reset task %5u for i/o through pNFS "
999 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1000 			hdr->task.tk_pid,
1001 			hdr->inode->i_sb->s_id,
1002 			(unsigned long long)NFS_FILEID(hdr->inode),
1003 			hdr->args.count,
1004 			(unsigned long long)hdr->args.offset);
1005 
1006 		hdr->completion_ops->reschedule_io(hdr);
1007 		return;
1008 	}
1009 
1010 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1011 		dprintk("%s Reset task %5u for i/o through MDS "
1012 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1013 			hdr->task.tk_pid,
1014 			hdr->inode->i_sb->s_id,
1015 			(unsigned long long)NFS_FILEID(hdr->inode),
1016 			hdr->args.count,
1017 			(unsigned long long)hdr->args.offset);
1018 
1019 		task->tk_status = pnfs_write_done_resend_to_mds(hdr);
1020 	}
1021 }
1022 
1023 static void ff_layout_reset_read(struct nfs_pgio_header *hdr)
1024 {
1025 	struct rpc_task *task = &hdr->task;
1026 
1027 	pnfs_layoutcommit_inode(hdr->inode, false);
1028 
1029 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1030 		dprintk("%s Reset task %5u for i/o through MDS "
1031 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1032 			hdr->task.tk_pid,
1033 			hdr->inode->i_sb->s_id,
1034 			(unsigned long long)NFS_FILEID(hdr->inode),
1035 			hdr->args.count,
1036 			(unsigned long long)hdr->args.offset);
1037 
1038 		task->tk_status = pnfs_read_done_resend_to_mds(hdr);
1039 	}
1040 }
1041 
1042 static int ff_layout_async_handle_error_v4(struct rpc_task *task,
1043 					   struct nfs4_state *state,
1044 					   struct nfs_client *clp,
1045 					   struct pnfs_layout_segment *lseg,
1046 					   int idx)
1047 {
1048 	struct pnfs_layout_hdr *lo = lseg->pls_layout;
1049 	struct inode *inode = lo->plh_inode;
1050 	struct nfs_server *mds_server = NFS_SERVER(inode);
1051 
1052 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1053 	struct nfs_client *mds_client = mds_server->nfs_client;
1054 	struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
1055 
1056 	if (task->tk_status >= 0)
1057 		return 0;
1058 
1059 	switch (task->tk_status) {
1060 	/* MDS state errors */
1061 	case -NFS4ERR_DELEG_REVOKED:
1062 	case -NFS4ERR_ADMIN_REVOKED:
1063 	case -NFS4ERR_BAD_STATEID:
1064 		if (state == NULL)
1065 			break;
1066 		nfs_remove_bad_delegation(state->inode, NULL);
1067 	case -NFS4ERR_OPENMODE:
1068 		if (state == NULL)
1069 			break;
1070 		if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
1071 			goto out_bad_stateid;
1072 		goto wait_on_recovery;
1073 	case -NFS4ERR_EXPIRED:
1074 		if (state != NULL) {
1075 			if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
1076 				goto out_bad_stateid;
1077 		}
1078 		nfs4_schedule_lease_recovery(mds_client);
1079 		goto wait_on_recovery;
1080 	/* DS session errors */
1081 	case -NFS4ERR_BADSESSION:
1082 	case -NFS4ERR_BADSLOT:
1083 	case -NFS4ERR_BAD_HIGH_SLOT:
1084 	case -NFS4ERR_DEADSESSION:
1085 	case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
1086 	case -NFS4ERR_SEQ_FALSE_RETRY:
1087 	case -NFS4ERR_SEQ_MISORDERED:
1088 		dprintk("%s ERROR %d, Reset session. Exchangeid "
1089 			"flags 0x%x\n", __func__, task->tk_status,
1090 			clp->cl_exchange_flags);
1091 		nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
1092 		break;
1093 	case -NFS4ERR_DELAY:
1094 	case -NFS4ERR_GRACE:
1095 		rpc_delay(task, FF_LAYOUT_POLL_RETRY_MAX);
1096 		break;
1097 	case -NFS4ERR_RETRY_UNCACHED_REP:
1098 		break;
1099 	/* Invalidate Layout errors */
1100 	case -NFS4ERR_PNFS_NO_LAYOUT:
1101 	case -ESTALE:           /* mapped NFS4ERR_STALE */
1102 	case -EBADHANDLE:       /* mapped NFS4ERR_BADHANDLE */
1103 	case -EISDIR:           /* mapped NFS4ERR_ISDIR */
1104 	case -NFS4ERR_FHEXPIRED:
1105 	case -NFS4ERR_WRONG_TYPE:
1106 		dprintk("%s Invalid layout error %d\n", __func__,
1107 			task->tk_status);
1108 		/*
1109 		 * Destroy layout so new i/o will get a new layout.
1110 		 * Layout will not be destroyed until all current lseg
1111 		 * references are put. Mark layout as invalid to resend failed
1112 		 * i/o and all i/o waiting on the slot table to the MDS until
1113 		 * layout is destroyed and a new valid layout is obtained.
1114 		 */
1115 		pnfs_destroy_layout(NFS_I(inode));
1116 		rpc_wake_up(&tbl->slot_tbl_waitq);
1117 		goto reset;
1118 	/* RPC connection errors */
1119 	case -ECONNREFUSED:
1120 	case -EHOSTDOWN:
1121 	case -EHOSTUNREACH:
1122 	case -ENETUNREACH:
1123 	case -EIO:
1124 	case -ETIMEDOUT:
1125 	case -EPIPE:
1126 		dprintk("%s DS connection error %d\n", __func__,
1127 			task->tk_status);
1128 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1129 				&devid->deviceid);
1130 		rpc_wake_up(&tbl->slot_tbl_waitq);
1131 		/* fall through */
1132 	default:
1133 		if (ff_layout_avoid_mds_available_ds(lseg))
1134 			return -NFS4ERR_RESET_TO_PNFS;
1135 reset:
1136 		dprintk("%s Retry through MDS. Error %d\n", __func__,
1137 			task->tk_status);
1138 		return -NFS4ERR_RESET_TO_MDS;
1139 	}
1140 out:
1141 	task->tk_status = 0;
1142 	return -EAGAIN;
1143 out_bad_stateid:
1144 	task->tk_status = -EIO;
1145 	return 0;
1146 wait_on_recovery:
1147 	rpc_sleep_on(&mds_client->cl_rpcwaitq, task, NULL);
1148 	if (test_bit(NFS4CLNT_MANAGER_RUNNING, &mds_client->cl_state) == 0)
1149 		rpc_wake_up_queued_task(&mds_client->cl_rpcwaitq, task);
1150 	goto out;
1151 }
1152 
1153 /* Retry all errors through either pNFS or MDS except for -EJUKEBOX */
1154 static int ff_layout_async_handle_error_v3(struct rpc_task *task,
1155 					   struct pnfs_layout_segment *lseg,
1156 					   int idx)
1157 {
1158 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1159 
1160 	if (task->tk_status >= 0)
1161 		return 0;
1162 
1163 	switch (task->tk_status) {
1164 	/* File access problems. Don't mark the device as unavailable */
1165 	case -EACCES:
1166 	case -ESTALE:
1167 	case -EISDIR:
1168 	case -EBADHANDLE:
1169 	case -ELOOP:
1170 	case -ENOSPC:
1171 		break;
1172 	case -EJUKEBOX:
1173 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1174 		goto out_retry;
1175 	default:
1176 		dprintk("%s DS connection error %d\n", __func__,
1177 			task->tk_status);
1178 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1179 				&devid->deviceid);
1180 	}
1181 	/* FIXME: Need to prevent infinite looping here. */
1182 	return -NFS4ERR_RESET_TO_PNFS;
1183 out_retry:
1184 	task->tk_status = 0;
1185 	rpc_restart_call_prepare(task);
1186 	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
1187 	return -EAGAIN;
1188 }
1189 
1190 static int ff_layout_async_handle_error(struct rpc_task *task,
1191 					struct nfs4_state *state,
1192 					struct nfs_client *clp,
1193 					struct pnfs_layout_segment *lseg,
1194 					int idx)
1195 {
1196 	int vers = clp->cl_nfs_mod->rpc_vers->number;
1197 
1198 	switch (vers) {
1199 	case 3:
1200 		return ff_layout_async_handle_error_v3(task, lseg, idx);
1201 	case 4:
1202 		return ff_layout_async_handle_error_v4(task, state, clp,
1203 						       lseg, idx);
1204 	default:
1205 		/* should never happen */
1206 		WARN_ON_ONCE(1);
1207 		return 0;
1208 	}
1209 }
1210 
1211 static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg,
1212 					int idx, u64 offset, u64 length,
1213 					u32 status, int opnum, int error)
1214 {
1215 	struct nfs4_ff_layout_mirror *mirror;
1216 	int err;
1217 
1218 	if (status == 0) {
1219 		switch (error) {
1220 		case -ETIMEDOUT:
1221 		case -EPFNOSUPPORT:
1222 		case -EPROTONOSUPPORT:
1223 		case -EOPNOTSUPP:
1224 		case -ECONNREFUSED:
1225 		case -ECONNRESET:
1226 		case -EHOSTDOWN:
1227 		case -EHOSTUNREACH:
1228 		case -ENETUNREACH:
1229 		case -EADDRINUSE:
1230 		case -ENOBUFS:
1231 		case -EPIPE:
1232 		case -EPERM:
1233 			status = NFS4ERR_NXIO;
1234 			break;
1235 		case -EACCES:
1236 			status = NFS4ERR_ACCESS;
1237 			break;
1238 		default:
1239 			return;
1240 		}
1241 	}
1242 
1243 	switch (status) {
1244 	case NFS4ERR_DELAY:
1245 	case NFS4ERR_GRACE:
1246 		return;
1247 	default:
1248 		break;
1249 	}
1250 
1251 	mirror = FF_LAYOUT_COMP(lseg, idx);
1252 	err = ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),
1253 				       mirror, offset, length, status, opnum,
1254 				       GFP_NOIO);
1255 	pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode, lseg);
1256 	dprintk("%s: err %d op %d status %u\n", __func__, err, opnum, status);
1257 }
1258 
1259 /* NFS_PROTO call done callback routines */
1260 static int ff_layout_read_done_cb(struct rpc_task *task,
1261 				struct nfs_pgio_header *hdr)
1262 {
1263 	int err;
1264 
1265 	trace_nfs4_pnfs_read(hdr, task->tk_status);
1266 	if (task->tk_status < 0)
1267 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1268 					    hdr->args.offset, hdr->args.count,
1269 					    hdr->res.op_status, OP_READ,
1270 					    task->tk_status);
1271 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1272 					   hdr->ds_clp, hdr->lseg,
1273 					   hdr->pgio_mirror_idx);
1274 
1275 	switch (err) {
1276 	case -NFS4ERR_RESET_TO_PNFS:
1277 		if (ff_layout_choose_best_ds_for_read(hdr->lseg,
1278 					hdr->pgio_mirror_idx + 1,
1279 					&hdr->pgio_mirror_idx))
1280 			goto out_eagain;
1281 		ff_layout_read_record_layoutstats_done(task, hdr);
1282 		pnfs_read_resend_pnfs(hdr);
1283 		return task->tk_status;
1284 	case -NFS4ERR_RESET_TO_MDS:
1285 		ff_layout_reset_read(hdr);
1286 		return task->tk_status;
1287 	case -EAGAIN:
1288 		goto out_eagain;
1289 	}
1290 
1291 	return 0;
1292 out_eagain:
1293 	rpc_restart_call_prepare(task);
1294 	return -EAGAIN;
1295 }
1296 
1297 static bool
1298 ff_layout_need_layoutcommit(struct pnfs_layout_segment *lseg)
1299 {
1300 	return !(FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_LAYOUTCOMMIT);
1301 }
1302 
1303 /*
1304  * We reference the rpc_cred of the first WRITE that triggers the need for
1305  * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
1306  * rfc5661 is not clear about which credential should be used.
1307  *
1308  * Flexlayout client should treat DS replied FILE_SYNC as DATA_SYNC, so
1309  * to follow http://www.rfc-editor.org/errata_search.php?rfc=5661&eid=2751
1310  * we always send layoutcommit after DS writes.
1311  */
1312 static void
1313 ff_layout_set_layoutcommit(struct inode *inode,
1314 		struct pnfs_layout_segment *lseg,
1315 		loff_t end_offset)
1316 {
1317 	if (!ff_layout_need_layoutcommit(lseg))
1318 		return;
1319 
1320 	pnfs_set_layoutcommit(inode, lseg, end_offset);
1321 	dprintk("%s inode %lu pls_end_pos %llu\n", __func__, inode->i_ino,
1322 		(unsigned long long) NFS_I(inode)->layout->plh_lwb);
1323 }
1324 
1325 static bool
1326 ff_layout_device_unavailable(struct pnfs_layout_segment *lseg, int idx)
1327 {
1328 	/* No mirroring for now */
1329 	struct nfs4_deviceid_node *node = FF_LAYOUT_DEVID_NODE(lseg, idx);
1330 
1331 	return ff_layout_test_devid_unavailable(node);
1332 }
1333 
1334 static void ff_layout_read_record_layoutstats_start(struct rpc_task *task,
1335 		struct nfs_pgio_header *hdr)
1336 {
1337 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1338 		return;
1339 	nfs4_ff_layout_stat_io_start_read(hdr->inode,
1340 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1341 			hdr->args.count,
1342 			task->tk_start);
1343 }
1344 
1345 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
1346 		struct nfs_pgio_header *hdr)
1347 {
1348 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1349 		return;
1350 	nfs4_ff_layout_stat_io_end_read(task,
1351 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1352 			hdr->args.count,
1353 			hdr->res.count);
1354 }
1355 
1356 static int ff_layout_read_prepare_common(struct rpc_task *task,
1357 					 struct nfs_pgio_header *hdr)
1358 {
1359 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1360 		rpc_exit(task, -EIO);
1361 		return -EIO;
1362 	}
1363 	if (ff_layout_device_unavailable(hdr->lseg, hdr->pgio_mirror_idx)) {
1364 		rpc_exit(task, -EHOSTDOWN);
1365 		return -EAGAIN;
1366 	}
1367 
1368 	ff_layout_read_record_layoutstats_start(task, hdr);
1369 	return 0;
1370 }
1371 
1372 /*
1373  * Call ops for the async read/write cases
1374  * In the case of dense layouts, the offset needs to be reset to its
1375  * original value.
1376  */
1377 static void ff_layout_read_prepare_v3(struct rpc_task *task, void *data)
1378 {
1379 	struct nfs_pgio_header *hdr = data;
1380 
1381 	if (ff_layout_read_prepare_common(task, hdr))
1382 		return;
1383 
1384 	rpc_call_start(task);
1385 }
1386 
1387 static int ff_layout_setup_sequence(struct nfs_client *ds_clp,
1388 				    struct nfs4_sequence_args *args,
1389 				    struct nfs4_sequence_res *res,
1390 				    struct rpc_task *task)
1391 {
1392 	if (ds_clp->cl_session)
1393 		return nfs41_setup_sequence(ds_clp->cl_session,
1394 					   args,
1395 					   res,
1396 					   task);
1397 	return nfs40_setup_sequence(ds_clp->cl_slot_tbl,
1398 				   args,
1399 				   res,
1400 				   task);
1401 }
1402 
1403 static void ff_layout_read_prepare_v4(struct rpc_task *task, void *data)
1404 {
1405 	struct nfs_pgio_header *hdr = data;
1406 
1407 	if (ff_layout_setup_sequence(hdr->ds_clp,
1408 				     &hdr->args.seq_args,
1409 				     &hdr->res.seq_res,
1410 				     task))
1411 		return;
1412 
1413 	if (ff_layout_read_prepare_common(task, hdr))
1414 		return;
1415 
1416 	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
1417 			hdr->args.lock_context, FMODE_READ) == -EIO)
1418 		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
1419 }
1420 
1421 static void ff_layout_read_call_done(struct rpc_task *task, void *data)
1422 {
1423 	struct nfs_pgio_header *hdr = data;
1424 
1425 	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
1426 
1427 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1428 	    task->tk_status == 0) {
1429 		nfs4_sequence_done(task, &hdr->res.seq_res);
1430 		return;
1431 	}
1432 
1433 	/* Note this may cause RPC to be resent */
1434 	hdr->mds_ops->rpc_call_done(task, hdr);
1435 }
1436 
1437 static void ff_layout_read_count_stats(struct rpc_task *task, void *data)
1438 {
1439 	struct nfs_pgio_header *hdr = data;
1440 
1441 	ff_layout_read_record_layoutstats_done(task, hdr);
1442 	rpc_count_iostats_metrics(task,
1443 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_READ]);
1444 }
1445 
1446 static void ff_layout_read_release(void *data)
1447 {
1448 	struct nfs_pgio_header *hdr = data;
1449 
1450 	ff_layout_read_record_layoutstats_done(&hdr->task, hdr);
1451 	pnfs_generic_rw_release(data);
1452 }
1453 
1454 
1455 static int ff_layout_write_done_cb(struct rpc_task *task,
1456 				struct nfs_pgio_header *hdr)
1457 {
1458 	loff_t end_offs = 0;
1459 	int err;
1460 
1461 	trace_nfs4_pnfs_write(hdr, task->tk_status);
1462 	if (task->tk_status < 0)
1463 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1464 					    hdr->args.offset, hdr->args.count,
1465 					    hdr->res.op_status, OP_WRITE,
1466 					    task->tk_status);
1467 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1468 					   hdr->ds_clp, hdr->lseg,
1469 					   hdr->pgio_mirror_idx);
1470 
1471 	switch (err) {
1472 	case -NFS4ERR_RESET_TO_PNFS:
1473 		ff_layout_reset_write(hdr, true);
1474 		return task->tk_status;
1475 	case -NFS4ERR_RESET_TO_MDS:
1476 		ff_layout_reset_write(hdr, false);
1477 		return task->tk_status;
1478 	case -EAGAIN:
1479 		return -EAGAIN;
1480 	}
1481 
1482 	if (hdr->res.verf->committed == NFS_FILE_SYNC ||
1483 	    hdr->res.verf->committed == NFS_DATA_SYNC)
1484 		end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
1485 
1486 	/* Note: if the write is unstable, don't set end_offs until commit */
1487 	ff_layout_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
1488 
1489 	/* zero out fattr since we don't care DS attr at all */
1490 	hdr->fattr.valid = 0;
1491 	if (task->tk_status >= 0)
1492 		nfs_writeback_update_inode(hdr);
1493 
1494 	return 0;
1495 }
1496 
1497 static int ff_layout_commit_done_cb(struct rpc_task *task,
1498 				     struct nfs_commit_data *data)
1499 {
1500 	int err;
1501 
1502 	trace_nfs4_pnfs_commit_ds(data, task->tk_status);
1503 	if (task->tk_status < 0)
1504 		ff_layout_io_track_ds_error(data->lseg, data->ds_commit_index,
1505 					    data->args.offset, data->args.count,
1506 					    data->res.op_status, OP_COMMIT,
1507 					    task->tk_status);
1508 	err = ff_layout_async_handle_error(task, NULL, data->ds_clp,
1509 					   data->lseg, data->ds_commit_index);
1510 
1511 	switch (err) {
1512 	case -NFS4ERR_RESET_TO_PNFS:
1513 		pnfs_generic_prepare_to_resend_writes(data);
1514 		return -EAGAIN;
1515 	case -NFS4ERR_RESET_TO_MDS:
1516 		pnfs_generic_prepare_to_resend_writes(data);
1517 		return -EAGAIN;
1518 	case -EAGAIN:
1519 		rpc_restart_call_prepare(task);
1520 		return -EAGAIN;
1521 	}
1522 
1523 	ff_layout_set_layoutcommit(data->inode, data->lseg, data->lwb);
1524 
1525 	return 0;
1526 }
1527 
1528 static void ff_layout_write_record_layoutstats_start(struct rpc_task *task,
1529 		struct nfs_pgio_header *hdr)
1530 {
1531 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1532 		return;
1533 	nfs4_ff_layout_stat_io_start_write(hdr->inode,
1534 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1535 			hdr->args.count,
1536 			task->tk_start);
1537 }
1538 
1539 static void ff_layout_write_record_layoutstats_done(struct rpc_task *task,
1540 		struct nfs_pgio_header *hdr)
1541 {
1542 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1543 		return;
1544 	nfs4_ff_layout_stat_io_end_write(task,
1545 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1546 			hdr->args.count, hdr->res.count,
1547 			hdr->res.verf->committed);
1548 }
1549 
1550 static int ff_layout_write_prepare_common(struct rpc_task *task,
1551 					  struct nfs_pgio_header *hdr)
1552 {
1553 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1554 		rpc_exit(task, -EIO);
1555 		return -EIO;
1556 	}
1557 
1558 	if (ff_layout_device_unavailable(hdr->lseg, hdr->pgio_mirror_idx)) {
1559 		rpc_exit(task, -EHOSTDOWN);
1560 		return -EAGAIN;
1561 	}
1562 
1563 	ff_layout_write_record_layoutstats_start(task, hdr);
1564 	return 0;
1565 }
1566 
1567 static void ff_layout_write_prepare_v3(struct rpc_task *task, void *data)
1568 {
1569 	struct nfs_pgio_header *hdr = data;
1570 
1571 	if (ff_layout_write_prepare_common(task, hdr))
1572 		return;
1573 
1574 	rpc_call_start(task);
1575 }
1576 
1577 static void ff_layout_write_prepare_v4(struct rpc_task *task, void *data)
1578 {
1579 	struct nfs_pgio_header *hdr = data;
1580 
1581 	if (ff_layout_setup_sequence(hdr->ds_clp,
1582 				     &hdr->args.seq_args,
1583 				     &hdr->res.seq_res,
1584 				     task))
1585 		return;
1586 
1587 	if (ff_layout_write_prepare_common(task, hdr))
1588 		return;
1589 
1590 	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
1591 			hdr->args.lock_context, FMODE_WRITE) == -EIO)
1592 		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
1593 }
1594 
1595 static void ff_layout_write_call_done(struct rpc_task *task, void *data)
1596 {
1597 	struct nfs_pgio_header *hdr = data;
1598 
1599 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1600 	    task->tk_status == 0) {
1601 		nfs4_sequence_done(task, &hdr->res.seq_res);
1602 		return;
1603 	}
1604 
1605 	/* Note this may cause RPC to be resent */
1606 	hdr->mds_ops->rpc_call_done(task, hdr);
1607 }
1608 
1609 static void ff_layout_write_count_stats(struct rpc_task *task, void *data)
1610 {
1611 	struct nfs_pgio_header *hdr = data;
1612 
1613 	ff_layout_write_record_layoutstats_done(task, hdr);
1614 	rpc_count_iostats_metrics(task,
1615 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_WRITE]);
1616 }
1617 
1618 static void ff_layout_write_release(void *data)
1619 {
1620 	struct nfs_pgio_header *hdr = data;
1621 
1622 	ff_layout_write_record_layoutstats_done(&hdr->task, hdr);
1623 	pnfs_generic_rw_release(data);
1624 }
1625 
1626 static void ff_layout_commit_record_layoutstats_start(struct rpc_task *task,
1627 		struct nfs_commit_data *cdata)
1628 {
1629 	if (test_and_set_bit(NFS_IOHDR_STAT, &cdata->flags))
1630 		return;
1631 	nfs4_ff_layout_stat_io_start_write(cdata->inode,
1632 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1633 			0, task->tk_start);
1634 }
1635 
1636 static void ff_layout_commit_record_layoutstats_done(struct rpc_task *task,
1637 		struct nfs_commit_data *cdata)
1638 {
1639 	struct nfs_page *req;
1640 	__u64 count = 0;
1641 
1642 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &cdata->flags))
1643 		return;
1644 
1645 	if (task->tk_status == 0) {
1646 		list_for_each_entry(req, &cdata->pages, wb_list)
1647 			count += req->wb_bytes;
1648 	}
1649 	nfs4_ff_layout_stat_io_end_write(task,
1650 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1651 			count, count, NFS_FILE_SYNC);
1652 }
1653 
1654 static void ff_layout_commit_prepare_common(struct rpc_task *task,
1655 		struct nfs_commit_data *cdata)
1656 {
1657 	ff_layout_commit_record_layoutstats_start(task, cdata);
1658 }
1659 
1660 static void ff_layout_commit_prepare_v3(struct rpc_task *task, void *data)
1661 {
1662 	ff_layout_commit_prepare_common(task, data);
1663 	rpc_call_start(task);
1664 }
1665 
1666 static void ff_layout_commit_prepare_v4(struct rpc_task *task, void *data)
1667 {
1668 	struct nfs_commit_data *wdata = data;
1669 
1670 	if (ff_layout_setup_sequence(wdata->ds_clp,
1671 				 &wdata->args.seq_args,
1672 				 &wdata->res.seq_res,
1673 				 task))
1674 		return;
1675 	ff_layout_commit_prepare_common(task, data);
1676 }
1677 
1678 static void ff_layout_commit_done(struct rpc_task *task, void *data)
1679 {
1680 	pnfs_generic_write_commit_done(task, data);
1681 }
1682 
1683 static void ff_layout_commit_count_stats(struct rpc_task *task, void *data)
1684 {
1685 	struct nfs_commit_data *cdata = data;
1686 
1687 	ff_layout_commit_record_layoutstats_done(task, cdata);
1688 	rpc_count_iostats_metrics(task,
1689 	    &NFS_CLIENT(cdata->inode)->cl_metrics[NFSPROC4_CLNT_COMMIT]);
1690 }
1691 
1692 static void ff_layout_commit_release(void *data)
1693 {
1694 	struct nfs_commit_data *cdata = data;
1695 
1696 	ff_layout_commit_record_layoutstats_done(&cdata->task, cdata);
1697 	pnfs_generic_commit_release(data);
1698 }
1699 
1700 static const struct rpc_call_ops ff_layout_read_call_ops_v3 = {
1701 	.rpc_call_prepare = ff_layout_read_prepare_v3,
1702 	.rpc_call_done = ff_layout_read_call_done,
1703 	.rpc_count_stats = ff_layout_read_count_stats,
1704 	.rpc_release = ff_layout_read_release,
1705 };
1706 
1707 static const struct rpc_call_ops ff_layout_read_call_ops_v4 = {
1708 	.rpc_call_prepare = ff_layout_read_prepare_v4,
1709 	.rpc_call_done = ff_layout_read_call_done,
1710 	.rpc_count_stats = ff_layout_read_count_stats,
1711 	.rpc_release = ff_layout_read_release,
1712 };
1713 
1714 static const struct rpc_call_ops ff_layout_write_call_ops_v3 = {
1715 	.rpc_call_prepare = ff_layout_write_prepare_v3,
1716 	.rpc_call_done = ff_layout_write_call_done,
1717 	.rpc_count_stats = ff_layout_write_count_stats,
1718 	.rpc_release = ff_layout_write_release,
1719 };
1720 
1721 static const struct rpc_call_ops ff_layout_write_call_ops_v4 = {
1722 	.rpc_call_prepare = ff_layout_write_prepare_v4,
1723 	.rpc_call_done = ff_layout_write_call_done,
1724 	.rpc_count_stats = ff_layout_write_count_stats,
1725 	.rpc_release = ff_layout_write_release,
1726 };
1727 
1728 static const struct rpc_call_ops ff_layout_commit_call_ops_v3 = {
1729 	.rpc_call_prepare = ff_layout_commit_prepare_v3,
1730 	.rpc_call_done = ff_layout_commit_done,
1731 	.rpc_count_stats = ff_layout_commit_count_stats,
1732 	.rpc_release = ff_layout_commit_release,
1733 };
1734 
1735 static const struct rpc_call_ops ff_layout_commit_call_ops_v4 = {
1736 	.rpc_call_prepare = ff_layout_commit_prepare_v4,
1737 	.rpc_call_done = ff_layout_commit_done,
1738 	.rpc_count_stats = ff_layout_commit_count_stats,
1739 	.rpc_release = ff_layout_commit_release,
1740 };
1741 
1742 static enum pnfs_try_status
1743 ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
1744 {
1745 	struct pnfs_layout_segment *lseg = hdr->lseg;
1746 	struct nfs4_pnfs_ds *ds;
1747 	struct rpc_clnt *ds_clnt;
1748 	struct rpc_cred *ds_cred;
1749 	loff_t offset = hdr->args.offset;
1750 	u32 idx = hdr->pgio_mirror_idx;
1751 	int vers;
1752 	struct nfs_fh *fh;
1753 
1754 	dprintk("--> %s ino %lu pgbase %u req %Zu@%llu\n",
1755 		__func__, hdr->inode->i_ino,
1756 		hdr->args.pgbase, (size_t)hdr->args.count, offset);
1757 
1758 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, false);
1759 	if (!ds)
1760 		goto out_failed;
1761 
1762 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1763 						   hdr->inode);
1764 	if (IS_ERR(ds_clnt))
1765 		goto out_failed;
1766 
1767 	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
1768 	if (!ds_cred)
1769 		goto out_failed;
1770 
1771 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1772 
1773 	dprintk("%s USE DS: %s cl_count %d vers %d\n", __func__,
1774 		ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count), vers);
1775 
1776 	hdr->pgio_done_cb = ff_layout_read_done_cb;
1777 	atomic_inc(&ds->ds_clp->cl_count);
1778 	hdr->ds_clp = ds->ds_clp;
1779 	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
1780 	if (fh)
1781 		hdr->args.fh = fh;
1782 	/*
1783 	 * Note that if we ever decide to split across DSes,
1784 	 * then we may need to handle dense-like offsets.
1785 	 */
1786 	hdr->args.offset = offset;
1787 	hdr->mds_offset = offset;
1788 
1789 	/* Perform an asynchronous read to ds */
1790 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1791 			  vers == 3 ? &ff_layout_read_call_ops_v3 :
1792 				      &ff_layout_read_call_ops_v4,
1793 			  0, RPC_TASK_SOFTCONN);
1794 	put_rpccred(ds_cred);
1795 	return PNFS_ATTEMPTED;
1796 
1797 out_failed:
1798 	if (ff_layout_avoid_mds_available_ds(lseg))
1799 		return PNFS_TRY_AGAIN;
1800 	return PNFS_NOT_ATTEMPTED;
1801 }
1802 
1803 /* Perform async writes. */
1804 static enum pnfs_try_status
1805 ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
1806 {
1807 	struct pnfs_layout_segment *lseg = hdr->lseg;
1808 	struct nfs4_pnfs_ds *ds;
1809 	struct rpc_clnt *ds_clnt;
1810 	struct rpc_cred *ds_cred;
1811 	loff_t offset = hdr->args.offset;
1812 	int vers;
1813 	struct nfs_fh *fh;
1814 	int idx = hdr->pgio_mirror_idx;
1815 
1816 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
1817 	if (!ds)
1818 		return PNFS_NOT_ATTEMPTED;
1819 
1820 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1821 						   hdr->inode);
1822 	if (IS_ERR(ds_clnt))
1823 		return PNFS_NOT_ATTEMPTED;
1824 
1825 	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
1826 	if (!ds_cred)
1827 		return PNFS_NOT_ATTEMPTED;
1828 
1829 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1830 
1831 	dprintk("%s ino %lu sync %d req %Zu@%llu DS: %s cl_count %d vers %d\n",
1832 		__func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
1833 		offset, ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count),
1834 		vers);
1835 
1836 	hdr->pgio_done_cb = ff_layout_write_done_cb;
1837 	atomic_inc(&ds->ds_clp->cl_count);
1838 	hdr->ds_clp = ds->ds_clp;
1839 	hdr->ds_commit_idx = idx;
1840 	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
1841 	if (fh)
1842 		hdr->args.fh = fh;
1843 
1844 	/*
1845 	 * Note that if we ever decide to split across DSes,
1846 	 * then we may need to handle dense-like offsets.
1847 	 */
1848 	hdr->args.offset = offset;
1849 
1850 	/* Perform an asynchronous write */
1851 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1852 			  vers == 3 ? &ff_layout_write_call_ops_v3 :
1853 				      &ff_layout_write_call_ops_v4,
1854 			  sync, RPC_TASK_SOFTCONN);
1855 	put_rpccred(ds_cred);
1856 	return PNFS_ATTEMPTED;
1857 }
1858 
1859 static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1860 {
1861 	return i;
1862 }
1863 
1864 static struct nfs_fh *
1865 select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1866 {
1867 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
1868 
1869 	/* FIXME: Assume that there is only one NFS version available
1870 	 * for the DS.
1871 	 */
1872 	return &flseg->mirror_array[i]->fh_versions[0];
1873 }
1874 
1875 static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
1876 {
1877 	struct pnfs_layout_segment *lseg = data->lseg;
1878 	struct nfs4_pnfs_ds *ds;
1879 	struct rpc_clnt *ds_clnt;
1880 	struct rpc_cred *ds_cred;
1881 	u32 idx;
1882 	int vers, ret;
1883 	struct nfs_fh *fh;
1884 
1885 	idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
1886 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
1887 	if (!ds)
1888 		goto out_err;
1889 
1890 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1891 						   data->inode);
1892 	if (IS_ERR(ds_clnt))
1893 		goto out_err;
1894 
1895 	ds_cred = ff_layout_get_ds_cred(lseg, idx, data->cred);
1896 	if (!ds_cred)
1897 		goto out_err;
1898 
1899 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1900 
1901 	dprintk("%s ino %lu, how %d cl_count %d vers %d\n", __func__,
1902 		data->inode->i_ino, how, atomic_read(&ds->ds_clp->cl_count),
1903 		vers);
1904 	data->commit_done_cb = ff_layout_commit_done_cb;
1905 	data->cred = ds_cred;
1906 	atomic_inc(&ds->ds_clp->cl_count);
1907 	data->ds_clp = ds->ds_clp;
1908 	fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
1909 	if (fh)
1910 		data->args.fh = fh;
1911 
1912 	ret = nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
1913 				   vers == 3 ? &ff_layout_commit_call_ops_v3 :
1914 					       &ff_layout_commit_call_ops_v4,
1915 				   how, RPC_TASK_SOFTCONN);
1916 	put_rpccred(ds_cred);
1917 	return ret;
1918 out_err:
1919 	pnfs_generic_prepare_to_resend_writes(data);
1920 	pnfs_generic_commit_release(data);
1921 	return -EAGAIN;
1922 }
1923 
1924 static int
1925 ff_layout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
1926 			   int how, struct nfs_commit_info *cinfo)
1927 {
1928 	return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
1929 					    ff_layout_initiate_commit);
1930 }
1931 
1932 static struct pnfs_ds_commit_info *
1933 ff_layout_get_ds_info(struct inode *inode)
1934 {
1935 	struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
1936 
1937 	if (layout == NULL)
1938 		return NULL;
1939 
1940 	return &FF_LAYOUT_FROM_HDR(layout)->commit_info;
1941 }
1942 
1943 static void
1944 ff_layout_free_deviceid_node(struct nfs4_deviceid_node *d)
1945 {
1946 	nfs4_ff_layout_free_deviceid(container_of(d, struct nfs4_ff_layout_ds,
1947 						  id_node));
1948 }
1949 
1950 static int ff_layout_encode_ioerr(struct xdr_stream *xdr,
1951 				  const struct nfs4_layoutreturn_args *args,
1952 				  const struct nfs4_flexfile_layoutreturn_args *ff_args)
1953 {
1954 	__be32 *start;
1955 
1956 	start = xdr_reserve_space(xdr, 4);
1957 	if (unlikely(!start))
1958 		return -E2BIG;
1959 
1960 	*start = cpu_to_be32(ff_args->num_errors);
1961 	/* This assume we always return _ALL_ layouts */
1962 	return ff_layout_encode_ds_ioerr(xdr, &ff_args->errors);
1963 }
1964 
1965 static void
1966 encode_opaque_fixed(struct xdr_stream *xdr, const void *buf, size_t len)
1967 {
1968 	__be32 *p;
1969 
1970 	p = xdr_reserve_space(xdr, len);
1971 	xdr_encode_opaque_fixed(p, buf, len);
1972 }
1973 
1974 static void
1975 ff_layout_encode_ff_iostat_head(struct xdr_stream *xdr,
1976 			    const nfs4_stateid *stateid,
1977 			    const struct nfs42_layoutstat_devinfo *devinfo)
1978 {
1979 	__be32 *p;
1980 
1981 	p = xdr_reserve_space(xdr, 8 + 8);
1982 	p = xdr_encode_hyper(p, devinfo->offset);
1983 	p = xdr_encode_hyper(p, devinfo->length);
1984 	encode_opaque_fixed(xdr, stateid->data, NFS4_STATEID_SIZE);
1985 	p = xdr_reserve_space(xdr, 4*8);
1986 	p = xdr_encode_hyper(p, devinfo->read_count);
1987 	p = xdr_encode_hyper(p, devinfo->read_bytes);
1988 	p = xdr_encode_hyper(p, devinfo->write_count);
1989 	p = xdr_encode_hyper(p, devinfo->write_bytes);
1990 	encode_opaque_fixed(xdr, devinfo->dev_id.data, NFS4_DEVICEID4_SIZE);
1991 }
1992 
1993 static void
1994 ff_layout_encode_ff_iostat(struct xdr_stream *xdr,
1995 			    const nfs4_stateid *stateid,
1996 			    const struct nfs42_layoutstat_devinfo *devinfo)
1997 {
1998 	ff_layout_encode_ff_iostat_head(xdr, stateid, devinfo);
1999 	ff_layout_encode_ff_layoutupdate(xdr, devinfo,
2000 			devinfo->ld_private.data);
2001 }
2002 
2003 /* report nothing for now */
2004 static void ff_layout_encode_iostats_array(struct xdr_stream *xdr,
2005 		const struct nfs4_layoutreturn_args *args,
2006 		struct nfs4_flexfile_layoutreturn_args *ff_args)
2007 {
2008 	__be32 *p;
2009 	int i;
2010 
2011 	p = xdr_reserve_space(xdr, 4);
2012 	*p = cpu_to_be32(ff_args->num_dev);
2013 	for (i = 0; i < ff_args->num_dev; i++)
2014 		ff_layout_encode_ff_iostat(xdr,
2015 				&args->layout->plh_stateid,
2016 				&ff_args->devinfo[i]);
2017 }
2018 
2019 static void
2020 ff_layout_free_iostats_array(struct nfs42_layoutstat_devinfo *devinfo,
2021 		unsigned int num_entries)
2022 {
2023 	unsigned int i;
2024 
2025 	for (i = 0; i < num_entries; i++) {
2026 		if (!devinfo[i].ld_private.ops)
2027 			continue;
2028 		if (!devinfo[i].ld_private.ops->free)
2029 			continue;
2030 		devinfo[i].ld_private.ops->free(&devinfo[i].ld_private);
2031 	}
2032 }
2033 
2034 static struct nfs4_deviceid_node *
2035 ff_layout_alloc_deviceid_node(struct nfs_server *server,
2036 			      struct pnfs_device *pdev, gfp_t gfp_flags)
2037 {
2038 	struct nfs4_ff_layout_ds *dsaddr;
2039 
2040 	dsaddr = nfs4_ff_alloc_deviceid_node(server, pdev, gfp_flags);
2041 	if (!dsaddr)
2042 		return NULL;
2043 	return &dsaddr->id_node;
2044 }
2045 
2046 static void
2047 ff_layout_encode_layoutreturn(struct xdr_stream *xdr,
2048 		const void *voidargs,
2049 		const struct nfs4_xdr_opaque_data *ff_opaque)
2050 {
2051 	const struct nfs4_layoutreturn_args *args = voidargs;
2052 	struct nfs4_flexfile_layoutreturn_args *ff_args = ff_opaque->data;
2053 	struct xdr_buf tmp_buf = {
2054 		.head = {
2055 			[0] = {
2056 				.iov_base = page_address(ff_args->pages[0]),
2057 			},
2058 		},
2059 		.buflen = PAGE_SIZE,
2060 	};
2061 	struct xdr_stream tmp_xdr;
2062 	__be32 *start;
2063 
2064 	dprintk("%s: Begin\n", __func__);
2065 
2066 	xdr_init_encode(&tmp_xdr, &tmp_buf, NULL);
2067 
2068 	ff_layout_encode_ioerr(&tmp_xdr, args, ff_args);
2069 	ff_layout_encode_iostats_array(&tmp_xdr, args, ff_args);
2070 
2071 	start = xdr_reserve_space(xdr, 4);
2072 	*start = cpu_to_be32(tmp_buf.len);
2073 	xdr_write_pages(xdr, ff_args->pages, 0, tmp_buf.len);
2074 
2075 	dprintk("%s: Return\n", __func__);
2076 }
2077 
2078 static void
2079 ff_layout_free_layoutreturn(struct nfs4_xdr_opaque_data *args)
2080 {
2081 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2082 
2083 	if (!args->data)
2084 		return;
2085 	ff_args = args->data;
2086 	args->data = NULL;
2087 
2088 	ff_layout_free_ds_ioerr(&ff_args->errors);
2089 	ff_layout_free_iostats_array(ff_args->devinfo, ff_args->num_dev);
2090 
2091 	put_page(ff_args->pages[0]);
2092 	kfree(ff_args);
2093 }
2094 
2095 const struct nfs4_xdr_opaque_ops layoutreturn_ops = {
2096 	.encode = ff_layout_encode_layoutreturn,
2097 	.free = ff_layout_free_layoutreturn,
2098 };
2099 
2100 static int
2101 ff_layout_prepare_layoutreturn(struct nfs4_layoutreturn_args *args)
2102 {
2103 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2104 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(args->layout);
2105 
2106 	ff_args = kmalloc(sizeof(*ff_args), GFP_KERNEL);
2107 	if (!ff_args)
2108 		goto out_nomem;
2109 	ff_args->pages[0] = alloc_page(GFP_KERNEL);
2110 	if (!ff_args->pages[0])
2111 		goto out_nomem_free;
2112 
2113 	INIT_LIST_HEAD(&ff_args->errors);
2114 	ff_args->num_errors = ff_layout_fetch_ds_ioerr(args->layout,
2115 			&args->range, &ff_args->errors,
2116 			FF_LAYOUTRETURN_MAXERR);
2117 
2118 	spin_lock(&args->inode->i_lock);
2119 	ff_args->num_dev = ff_layout_mirror_prepare_stats(&ff_layout->generic_hdr,
2120 			&ff_args->devinfo[0], ARRAY_SIZE(ff_args->devinfo));
2121 	spin_unlock(&args->inode->i_lock);
2122 
2123 	args->ld_private->ops = &layoutreturn_ops;
2124 	args->ld_private->data = ff_args;
2125 	return 0;
2126 out_nomem_free:
2127 	kfree(ff_args);
2128 out_nomem:
2129 	return -ENOMEM;
2130 }
2131 
2132 static int
2133 ff_layout_ntop4(const struct sockaddr *sap, char *buf, const size_t buflen)
2134 {
2135 	const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
2136 
2137 	return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
2138 }
2139 
2140 static size_t
2141 ff_layout_ntop6_noscopeid(const struct sockaddr *sap, char *buf,
2142 			  const int buflen)
2143 {
2144 	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
2145 	const struct in6_addr *addr = &sin6->sin6_addr;
2146 
2147 	/*
2148 	 * RFC 4291, Section 2.2.2
2149 	 *
2150 	 * Shorthanded ANY address
2151 	 */
2152 	if (ipv6_addr_any(addr))
2153 		return snprintf(buf, buflen, "::");
2154 
2155 	/*
2156 	 * RFC 4291, Section 2.2.2
2157 	 *
2158 	 * Shorthanded loopback address
2159 	 */
2160 	if (ipv6_addr_loopback(addr))
2161 		return snprintf(buf, buflen, "::1");
2162 
2163 	/*
2164 	 * RFC 4291, Section 2.2.3
2165 	 *
2166 	 * Special presentation address format for mapped v4
2167 	 * addresses.
2168 	 */
2169 	if (ipv6_addr_v4mapped(addr))
2170 		return snprintf(buf, buflen, "::ffff:%pI4",
2171 					&addr->s6_addr32[3]);
2172 
2173 	/*
2174 	 * RFC 4291, Section 2.2.1
2175 	 */
2176 	return snprintf(buf, buflen, "%pI6c", addr);
2177 }
2178 
2179 /* Derived from rpc_sockaddr2uaddr */
2180 static void
2181 ff_layout_encode_netaddr(struct xdr_stream *xdr, struct nfs4_pnfs_ds_addr *da)
2182 {
2183 	struct sockaddr *sap = (struct sockaddr *)&da->da_addr;
2184 	char portbuf[RPCBIND_MAXUADDRPLEN];
2185 	char addrbuf[RPCBIND_MAXUADDRLEN];
2186 	char *netid;
2187 	unsigned short port;
2188 	int len, netid_len;
2189 	__be32 *p;
2190 
2191 	switch (sap->sa_family) {
2192 	case AF_INET:
2193 		if (ff_layout_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
2194 			return;
2195 		port = ntohs(((struct sockaddr_in *)sap)->sin_port);
2196 		netid = "tcp";
2197 		netid_len = 3;
2198 		break;
2199 	case AF_INET6:
2200 		if (ff_layout_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
2201 			return;
2202 		port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
2203 		netid = "tcp6";
2204 		netid_len = 4;
2205 		break;
2206 	default:
2207 		/* we only support tcp and tcp6 */
2208 		WARN_ON_ONCE(1);
2209 		return;
2210 	}
2211 
2212 	snprintf(portbuf, sizeof(portbuf), ".%u.%u", port >> 8, port & 0xff);
2213 	len = strlcat(addrbuf, portbuf, sizeof(addrbuf));
2214 
2215 	p = xdr_reserve_space(xdr, 4 + netid_len);
2216 	xdr_encode_opaque(p, netid, netid_len);
2217 
2218 	p = xdr_reserve_space(xdr, 4 + len);
2219 	xdr_encode_opaque(p, addrbuf, len);
2220 }
2221 
2222 static void
2223 ff_layout_encode_nfstime(struct xdr_stream *xdr,
2224 			 ktime_t t)
2225 {
2226 	struct timespec64 ts;
2227 	__be32 *p;
2228 
2229 	p = xdr_reserve_space(xdr, 12);
2230 	ts = ktime_to_timespec64(t);
2231 	p = xdr_encode_hyper(p, ts.tv_sec);
2232 	*p++ = cpu_to_be32(ts.tv_nsec);
2233 }
2234 
2235 static void
2236 ff_layout_encode_io_latency(struct xdr_stream *xdr,
2237 			    struct nfs4_ff_io_stat *stat)
2238 {
2239 	__be32 *p;
2240 
2241 	p = xdr_reserve_space(xdr, 5 * 8);
2242 	p = xdr_encode_hyper(p, stat->ops_requested);
2243 	p = xdr_encode_hyper(p, stat->bytes_requested);
2244 	p = xdr_encode_hyper(p, stat->ops_completed);
2245 	p = xdr_encode_hyper(p, stat->bytes_completed);
2246 	p = xdr_encode_hyper(p, stat->bytes_not_delivered);
2247 	ff_layout_encode_nfstime(xdr, stat->total_busy_time);
2248 	ff_layout_encode_nfstime(xdr, stat->aggregate_completion_time);
2249 }
2250 
2251 static void
2252 ff_layout_encode_ff_layoutupdate(struct xdr_stream *xdr,
2253 			      const struct nfs42_layoutstat_devinfo *devinfo,
2254 			      struct nfs4_ff_layout_mirror *mirror)
2255 {
2256 	struct nfs4_pnfs_ds_addr *da;
2257 	struct nfs4_pnfs_ds *ds = mirror->mirror_ds->ds;
2258 	struct nfs_fh *fh = &mirror->fh_versions[0];
2259 	__be32 *p;
2260 
2261 	da = list_first_entry(&ds->ds_addrs, struct nfs4_pnfs_ds_addr, da_node);
2262 	dprintk("%s: DS %s: encoding address %s\n",
2263 		__func__, ds->ds_remotestr, da->da_remotestr);
2264 	/* netaddr4 */
2265 	ff_layout_encode_netaddr(xdr, da);
2266 	/* nfs_fh4 */
2267 	p = xdr_reserve_space(xdr, 4 + fh->size);
2268 	xdr_encode_opaque(p, fh->data, fh->size);
2269 	/* ff_io_latency4 read */
2270 	spin_lock(&mirror->lock);
2271 	ff_layout_encode_io_latency(xdr, &mirror->read_stat.io_stat);
2272 	/* ff_io_latency4 write */
2273 	ff_layout_encode_io_latency(xdr, &mirror->write_stat.io_stat);
2274 	spin_unlock(&mirror->lock);
2275 	/* nfstime4 */
2276 	ff_layout_encode_nfstime(xdr, ktime_sub(ktime_get(), mirror->start_time));
2277 	/* bool */
2278 	p = xdr_reserve_space(xdr, 4);
2279 	*p = cpu_to_be32(false);
2280 }
2281 
2282 static void
2283 ff_layout_encode_layoutstats(struct xdr_stream *xdr, const void *args,
2284 			     const struct nfs4_xdr_opaque_data *opaque)
2285 {
2286 	struct nfs42_layoutstat_devinfo *devinfo = container_of(opaque,
2287 			struct nfs42_layoutstat_devinfo, ld_private);
2288 	__be32 *start;
2289 
2290 	/* layoutupdate length */
2291 	start = xdr_reserve_space(xdr, 4);
2292 	ff_layout_encode_ff_layoutupdate(xdr, devinfo, opaque->data);
2293 
2294 	*start = cpu_to_be32((xdr->p - start - 1) * 4);
2295 }
2296 
2297 static void
2298 ff_layout_free_layoutstats(struct nfs4_xdr_opaque_data *opaque)
2299 {
2300 	struct nfs4_ff_layout_mirror *mirror = opaque->data;
2301 
2302 	ff_layout_put_mirror(mirror);
2303 }
2304 
2305 static const struct nfs4_xdr_opaque_ops layoutstat_ops = {
2306 	.encode = ff_layout_encode_layoutstats,
2307 	.free	= ff_layout_free_layoutstats,
2308 };
2309 
2310 static int
2311 ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
2312 			       struct nfs42_layoutstat_devinfo *devinfo,
2313 			       int dev_limit)
2314 {
2315 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
2316 	struct nfs4_ff_layout_mirror *mirror;
2317 	struct nfs4_deviceid_node *dev;
2318 	int i = 0;
2319 
2320 	list_for_each_entry(mirror, &ff_layout->mirrors, mirrors) {
2321 		if (i >= dev_limit)
2322 			break;
2323 		if (IS_ERR_OR_NULL(mirror->mirror_ds))
2324 			continue;
2325 		if (!test_and_clear_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags))
2326 			continue;
2327 		/* mirror refcount put in cleanup_layoutstats */
2328 		if (!atomic_inc_not_zero(&mirror->ref))
2329 			continue;
2330 		dev = &mirror->mirror_ds->id_node;
2331 		memcpy(&devinfo->dev_id, &dev->deviceid, NFS4_DEVICEID4_SIZE);
2332 		devinfo->offset = 0;
2333 		devinfo->length = NFS4_MAX_UINT64;
2334 		spin_lock(&mirror->lock);
2335 		devinfo->read_count = mirror->read_stat.io_stat.ops_completed;
2336 		devinfo->read_bytes = mirror->read_stat.io_stat.bytes_completed;
2337 		devinfo->write_count = mirror->write_stat.io_stat.ops_completed;
2338 		devinfo->write_bytes = mirror->write_stat.io_stat.bytes_completed;
2339 		spin_unlock(&mirror->lock);
2340 		devinfo->layout_type = LAYOUT_FLEX_FILES;
2341 		devinfo->ld_private.ops = &layoutstat_ops;
2342 		devinfo->ld_private.data = mirror;
2343 
2344 		devinfo++;
2345 		i++;
2346 	}
2347 	return i;
2348 }
2349 
2350 static int
2351 ff_layout_prepare_layoutstats(struct nfs42_layoutstat_args *args)
2352 {
2353 	struct nfs4_flexfile_layout *ff_layout;
2354 	const int dev_count = PNFS_LAYOUTSTATS_MAXDEV;
2355 
2356 	/* For now, send at most PNFS_LAYOUTSTATS_MAXDEV statistics */
2357 	args->devinfo = kmalloc_array(dev_count, sizeof(*args->devinfo), GFP_NOIO);
2358 	if (!args->devinfo)
2359 		return -ENOMEM;
2360 
2361 	spin_lock(&args->inode->i_lock);
2362 	ff_layout = FF_LAYOUT_FROM_HDR(NFS_I(args->inode)->layout);
2363 	args->num_dev = ff_layout_mirror_prepare_stats(&ff_layout->generic_hdr,
2364 			&args->devinfo[0], dev_count);
2365 	spin_unlock(&args->inode->i_lock);
2366 	if (!args->num_dev) {
2367 		kfree(args->devinfo);
2368 		args->devinfo = NULL;
2369 		return -ENOENT;
2370 	}
2371 
2372 	return 0;
2373 }
2374 
2375 static struct pnfs_layoutdriver_type flexfilelayout_type = {
2376 	.id			= LAYOUT_FLEX_FILES,
2377 	.name			= "LAYOUT_FLEX_FILES",
2378 	.owner			= THIS_MODULE,
2379 	.alloc_layout_hdr	= ff_layout_alloc_layout_hdr,
2380 	.free_layout_hdr	= ff_layout_free_layout_hdr,
2381 	.alloc_lseg		= ff_layout_alloc_lseg,
2382 	.free_lseg		= ff_layout_free_lseg,
2383 	.add_lseg		= ff_layout_add_lseg,
2384 	.pg_read_ops		= &ff_layout_pg_read_ops,
2385 	.pg_write_ops		= &ff_layout_pg_write_ops,
2386 	.get_ds_info		= ff_layout_get_ds_info,
2387 	.free_deviceid_node	= ff_layout_free_deviceid_node,
2388 	.mark_request_commit	= pnfs_layout_mark_request_commit,
2389 	.clear_request_commit	= pnfs_generic_clear_request_commit,
2390 	.scan_commit_lists	= pnfs_generic_scan_commit_lists,
2391 	.recover_commit_reqs	= pnfs_generic_recover_commit_reqs,
2392 	.commit_pagelist	= ff_layout_commit_pagelist,
2393 	.read_pagelist		= ff_layout_read_pagelist,
2394 	.write_pagelist		= ff_layout_write_pagelist,
2395 	.alloc_deviceid_node    = ff_layout_alloc_deviceid_node,
2396 	.prepare_layoutreturn   = ff_layout_prepare_layoutreturn,
2397 	.sync			= pnfs_nfs_generic_sync,
2398 	.prepare_layoutstats	= ff_layout_prepare_layoutstats,
2399 };
2400 
2401 static int __init nfs4flexfilelayout_init(void)
2402 {
2403 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Registering...\n",
2404 	       __func__);
2405 	if (!ff_zero_group) {
2406 		ff_zero_group = groups_alloc(0);
2407 		if (!ff_zero_group)
2408 			return -ENOMEM;
2409 	}
2410 	return pnfs_register_layoutdriver(&flexfilelayout_type);
2411 }
2412 
2413 static void __exit nfs4flexfilelayout_exit(void)
2414 {
2415 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Unregistering...\n",
2416 	       __func__);
2417 	pnfs_unregister_layoutdriver(&flexfilelayout_type);
2418 	if (ff_zero_group) {
2419 		put_group_info(ff_zero_group);
2420 		ff_zero_group = NULL;
2421 	}
2422 }
2423 
2424 MODULE_ALIAS("nfs-layouttype4-4");
2425 
2426 MODULE_LICENSE("GPL");
2427 MODULE_DESCRIPTION("The NFSv4 flexfile layout driver");
2428 
2429 module_init(nfs4flexfilelayout_init);
2430 module_exit(nfs4flexfilelayout_exit);
2431