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 	pnfs_generic_pg_check_layout(pgio);
850 	/* Use full layout for now */
851 	if (!pgio->pg_lseg)
852 		ff_layout_pg_get_read(pgio, req, false);
853 	else if (ff_layout_avoid_read_on_rw(pgio->pg_lseg))
854 		ff_layout_pg_get_read(pgio, req, true);
855 
856 	/* If no lseg, fall back to read through mds */
857 	if (pgio->pg_lseg == NULL)
858 		goto out_mds;
859 
860 	ds = ff_layout_choose_best_ds_for_read(pgio->pg_lseg, 0, &ds_idx);
861 	if (!ds) {
862 		if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
863 			goto out_mds;
864 		pnfs_put_lseg(pgio->pg_lseg);
865 		pgio->pg_lseg = NULL;
866 		/* Sleep for 1 second before retrying */
867 		ssleep(1);
868 		goto retry;
869 	}
870 
871 	mirror = FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx);
872 
873 	pgio->pg_mirror_idx = ds_idx;
874 
875 	/* read always uses only one mirror - idx 0 for pgio layer */
876 	pgm = &pgio->pg_mirrors[0];
877 	pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].rsize;
878 
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 nfs_server *mds_server = NFS_SERVER(inode);
1053 
1054 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1055 	struct nfs_client *mds_client = mds_server->nfs_client;
1056 	struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
1057 
1058 	switch (task->tk_status) {
1059 	/* MDS state errors */
1060 	case -NFS4ERR_DELEG_REVOKED:
1061 	case -NFS4ERR_ADMIN_REVOKED:
1062 	case -NFS4ERR_BAD_STATEID:
1063 		if (state == NULL)
1064 			break;
1065 		nfs_remove_bad_delegation(state->inode, NULL);
1066 	case -NFS4ERR_OPENMODE:
1067 		if (state == NULL)
1068 			break;
1069 		if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
1070 			goto out_bad_stateid;
1071 		goto wait_on_recovery;
1072 	case -NFS4ERR_EXPIRED:
1073 		if (state != NULL) {
1074 			if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
1075 				goto out_bad_stateid;
1076 		}
1077 		nfs4_schedule_lease_recovery(mds_client);
1078 		goto wait_on_recovery;
1079 	/* DS session errors */
1080 	case -NFS4ERR_BADSESSION:
1081 	case -NFS4ERR_BADSLOT:
1082 	case -NFS4ERR_BAD_HIGH_SLOT:
1083 	case -NFS4ERR_DEADSESSION:
1084 	case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
1085 	case -NFS4ERR_SEQ_FALSE_RETRY:
1086 	case -NFS4ERR_SEQ_MISORDERED:
1087 		dprintk("%s ERROR %d, Reset session. Exchangeid "
1088 			"flags 0x%x\n", __func__, task->tk_status,
1089 			clp->cl_exchange_flags);
1090 		nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
1091 		break;
1092 	case -NFS4ERR_DELAY:
1093 	case -NFS4ERR_GRACE:
1094 		rpc_delay(task, FF_LAYOUT_POLL_RETRY_MAX);
1095 		break;
1096 	case -NFS4ERR_RETRY_UNCACHED_REP:
1097 		break;
1098 	/* Invalidate Layout errors */
1099 	case -NFS4ERR_PNFS_NO_LAYOUT:
1100 	case -ESTALE:           /* mapped NFS4ERR_STALE */
1101 	case -EBADHANDLE:       /* mapped NFS4ERR_BADHANDLE */
1102 	case -EISDIR:           /* mapped NFS4ERR_ISDIR */
1103 	case -NFS4ERR_FHEXPIRED:
1104 	case -NFS4ERR_WRONG_TYPE:
1105 		dprintk("%s Invalid layout error %d\n", __func__,
1106 			task->tk_status);
1107 		/*
1108 		 * Destroy layout so new i/o will get a new layout.
1109 		 * Layout will not be destroyed until all current lseg
1110 		 * references are put. Mark layout as invalid to resend failed
1111 		 * i/o and all i/o waiting on the slot table to the MDS until
1112 		 * layout is destroyed and a new valid layout is obtained.
1113 		 */
1114 		pnfs_destroy_layout(NFS_I(inode));
1115 		rpc_wake_up(&tbl->slot_tbl_waitq);
1116 		goto reset;
1117 	/* RPC connection errors */
1118 	case -ECONNREFUSED:
1119 	case -EHOSTDOWN:
1120 	case -EHOSTUNREACH:
1121 	case -ENETUNREACH:
1122 	case -EIO:
1123 	case -ETIMEDOUT:
1124 	case -EPIPE:
1125 		dprintk("%s DS connection error %d\n", __func__,
1126 			task->tk_status);
1127 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1128 				&devid->deviceid);
1129 		rpc_wake_up(&tbl->slot_tbl_waitq);
1130 		/* fall through */
1131 	default:
1132 		if (ff_layout_avoid_mds_available_ds(lseg))
1133 			return -NFS4ERR_RESET_TO_PNFS;
1134 reset:
1135 		dprintk("%s Retry through MDS. Error %d\n", __func__,
1136 			task->tk_status);
1137 		return -NFS4ERR_RESET_TO_MDS;
1138 	}
1139 out:
1140 	task->tk_status = 0;
1141 	return -EAGAIN;
1142 out_bad_stateid:
1143 	task->tk_status = -EIO;
1144 	return 0;
1145 wait_on_recovery:
1146 	rpc_sleep_on(&mds_client->cl_rpcwaitq, task, NULL);
1147 	if (test_bit(NFS4CLNT_MANAGER_RUNNING, &mds_client->cl_state) == 0)
1148 		rpc_wake_up_queued_task(&mds_client->cl_rpcwaitq, task);
1149 	goto out;
1150 }
1151 
1152 /* Retry all errors through either pNFS or MDS except for -EJUKEBOX */
1153 static int ff_layout_async_handle_error_v3(struct rpc_task *task,
1154 					   struct pnfs_layout_segment *lseg,
1155 					   int idx)
1156 {
1157 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1158 
1159 	switch (task->tk_status) {
1160 	/* File access problems. Don't mark the device as unavailable */
1161 	case -EACCES:
1162 	case -ESTALE:
1163 	case -EISDIR:
1164 	case -EBADHANDLE:
1165 	case -ELOOP:
1166 	case -ENOSPC:
1167 		break;
1168 	case -EJUKEBOX:
1169 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1170 		goto out_retry;
1171 	default:
1172 		dprintk("%s DS connection error %d\n", __func__,
1173 			task->tk_status);
1174 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1175 				&devid->deviceid);
1176 	}
1177 	/* FIXME: Need to prevent infinite looping here. */
1178 	return -NFS4ERR_RESET_TO_PNFS;
1179 out_retry:
1180 	task->tk_status = 0;
1181 	rpc_restart_call_prepare(task);
1182 	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
1183 	return -EAGAIN;
1184 }
1185 
1186 static int ff_layout_async_handle_error(struct rpc_task *task,
1187 					struct nfs4_state *state,
1188 					struct nfs_client *clp,
1189 					struct pnfs_layout_segment *lseg,
1190 					int idx)
1191 {
1192 	int vers = clp->cl_nfs_mod->rpc_vers->number;
1193 
1194 	if (task->tk_status >= 0)
1195 		return 0;
1196 
1197 	/* Handle the case of an invalid layout segment */
1198 	if (!pnfs_is_valid_lseg(lseg))
1199 		return -NFS4ERR_RESET_TO_PNFS;
1200 
1201 	switch (vers) {
1202 	case 3:
1203 		return ff_layout_async_handle_error_v3(task, lseg, idx);
1204 	case 4:
1205 		return ff_layout_async_handle_error_v4(task, state, clp,
1206 						       lseg, idx);
1207 	default:
1208 		/* should never happen */
1209 		WARN_ON_ONCE(1);
1210 		return 0;
1211 	}
1212 }
1213 
1214 static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg,
1215 					int idx, u64 offset, u64 length,
1216 					u32 status, int opnum, int error)
1217 {
1218 	struct nfs4_ff_layout_mirror *mirror;
1219 	int err;
1220 
1221 	if (status == 0) {
1222 		switch (error) {
1223 		case -ETIMEDOUT:
1224 		case -EPFNOSUPPORT:
1225 		case -EPROTONOSUPPORT:
1226 		case -EOPNOTSUPP:
1227 		case -ECONNREFUSED:
1228 		case -ECONNRESET:
1229 		case -EHOSTDOWN:
1230 		case -EHOSTUNREACH:
1231 		case -ENETUNREACH:
1232 		case -EADDRINUSE:
1233 		case -ENOBUFS:
1234 		case -EPIPE:
1235 		case -EPERM:
1236 			status = NFS4ERR_NXIO;
1237 			break;
1238 		case -EACCES:
1239 			status = NFS4ERR_ACCESS;
1240 			break;
1241 		default:
1242 			return;
1243 		}
1244 	}
1245 
1246 	switch (status) {
1247 	case NFS4ERR_DELAY:
1248 	case NFS4ERR_GRACE:
1249 		return;
1250 	default:
1251 		break;
1252 	}
1253 
1254 	mirror = FF_LAYOUT_COMP(lseg, idx);
1255 	err = ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),
1256 				       mirror, offset, length, status, opnum,
1257 				       GFP_NOIO);
1258 	pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode, lseg);
1259 	dprintk("%s: err %d op %d status %u\n", __func__, err, opnum, status);
1260 }
1261 
1262 /* NFS_PROTO call done callback routines */
1263 static int ff_layout_read_done_cb(struct rpc_task *task,
1264 				struct nfs_pgio_header *hdr)
1265 {
1266 	int err;
1267 
1268 	trace_nfs4_pnfs_read(hdr, task->tk_status);
1269 	if (task->tk_status < 0)
1270 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1271 					    hdr->args.offset, hdr->args.count,
1272 					    hdr->res.op_status, OP_READ,
1273 					    task->tk_status);
1274 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1275 					   hdr->ds_clp, hdr->lseg,
1276 					   hdr->pgio_mirror_idx);
1277 
1278 	switch (err) {
1279 	case -NFS4ERR_RESET_TO_PNFS:
1280 		if (ff_layout_choose_best_ds_for_read(hdr->lseg,
1281 					hdr->pgio_mirror_idx + 1,
1282 					&hdr->pgio_mirror_idx))
1283 			goto out_eagain;
1284 		ff_layout_read_record_layoutstats_done(task, hdr);
1285 		pnfs_read_resend_pnfs(hdr);
1286 		return task->tk_status;
1287 	case -NFS4ERR_RESET_TO_MDS:
1288 		ff_layout_reset_read(hdr);
1289 		return task->tk_status;
1290 	case -EAGAIN:
1291 		goto out_eagain;
1292 	}
1293 
1294 	return 0;
1295 out_eagain:
1296 	rpc_restart_call_prepare(task);
1297 	return -EAGAIN;
1298 }
1299 
1300 static bool
1301 ff_layout_need_layoutcommit(struct pnfs_layout_segment *lseg)
1302 {
1303 	return !(FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_LAYOUTCOMMIT);
1304 }
1305 
1306 /*
1307  * We reference the rpc_cred of the first WRITE that triggers the need for
1308  * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
1309  * rfc5661 is not clear about which credential should be used.
1310  *
1311  * Flexlayout client should treat DS replied FILE_SYNC as DATA_SYNC, so
1312  * to follow http://www.rfc-editor.org/errata_search.php?rfc=5661&eid=2751
1313  * we always send layoutcommit after DS writes.
1314  */
1315 static void
1316 ff_layout_set_layoutcommit(struct inode *inode,
1317 		struct pnfs_layout_segment *lseg,
1318 		loff_t end_offset)
1319 {
1320 	if (!ff_layout_need_layoutcommit(lseg))
1321 		return;
1322 
1323 	pnfs_set_layoutcommit(inode, lseg, end_offset);
1324 	dprintk("%s inode %lu pls_end_pos %llu\n", __func__, inode->i_ino,
1325 		(unsigned long long) NFS_I(inode)->layout->plh_lwb);
1326 }
1327 
1328 static bool
1329 ff_layout_device_unavailable(struct pnfs_layout_segment *lseg, int idx)
1330 {
1331 	/* No mirroring for now */
1332 	struct nfs4_deviceid_node *node = FF_LAYOUT_DEVID_NODE(lseg, idx);
1333 
1334 	return ff_layout_test_devid_unavailable(node);
1335 }
1336 
1337 static void ff_layout_read_record_layoutstats_start(struct rpc_task *task,
1338 		struct nfs_pgio_header *hdr)
1339 {
1340 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1341 		return;
1342 	nfs4_ff_layout_stat_io_start_read(hdr->inode,
1343 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1344 			hdr->args.count,
1345 			task->tk_start);
1346 }
1347 
1348 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
1349 		struct nfs_pgio_header *hdr)
1350 {
1351 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1352 		return;
1353 	nfs4_ff_layout_stat_io_end_read(task,
1354 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1355 			hdr->args.count,
1356 			hdr->res.count);
1357 }
1358 
1359 static int ff_layout_read_prepare_common(struct rpc_task *task,
1360 					 struct nfs_pgio_header *hdr)
1361 {
1362 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1363 		rpc_exit(task, -EIO);
1364 		return -EIO;
1365 	}
1366 	if (ff_layout_device_unavailable(hdr->lseg, hdr->pgio_mirror_idx)) {
1367 		rpc_exit(task, -EHOSTDOWN);
1368 		return -EAGAIN;
1369 	}
1370 
1371 	ff_layout_read_record_layoutstats_start(task, hdr);
1372 	return 0;
1373 }
1374 
1375 /*
1376  * Call ops for the async read/write cases
1377  * In the case of dense layouts, the offset needs to be reset to its
1378  * original value.
1379  */
1380 static void ff_layout_read_prepare_v3(struct rpc_task *task, void *data)
1381 {
1382 	struct nfs_pgio_header *hdr = data;
1383 
1384 	if (ff_layout_read_prepare_common(task, hdr))
1385 		return;
1386 
1387 	rpc_call_start(task);
1388 }
1389 
1390 static void ff_layout_read_prepare_v4(struct rpc_task *task, void *data)
1391 {
1392 	struct nfs_pgio_header *hdr = data;
1393 
1394 	if (nfs4_setup_sequence(hdr->ds_clp,
1395 				&hdr->args.seq_args,
1396 				&hdr->res.seq_res,
1397 				task))
1398 		return;
1399 
1400 	if (ff_layout_read_prepare_common(task, hdr))
1401 		return;
1402 
1403 	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
1404 			hdr->args.lock_context, FMODE_READ) == -EIO)
1405 		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
1406 }
1407 
1408 static void ff_layout_read_call_done(struct rpc_task *task, void *data)
1409 {
1410 	struct nfs_pgio_header *hdr = data;
1411 
1412 	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
1413 
1414 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1415 	    task->tk_status == 0) {
1416 		nfs4_sequence_done(task, &hdr->res.seq_res);
1417 		return;
1418 	}
1419 
1420 	/* Note this may cause RPC to be resent */
1421 	hdr->mds_ops->rpc_call_done(task, hdr);
1422 }
1423 
1424 static void ff_layout_read_count_stats(struct rpc_task *task, void *data)
1425 {
1426 	struct nfs_pgio_header *hdr = data;
1427 
1428 	ff_layout_read_record_layoutstats_done(task, hdr);
1429 	rpc_count_iostats_metrics(task,
1430 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_READ]);
1431 }
1432 
1433 static void ff_layout_read_release(void *data)
1434 {
1435 	struct nfs_pgio_header *hdr = data;
1436 
1437 	ff_layout_read_record_layoutstats_done(&hdr->task, hdr);
1438 	pnfs_generic_rw_release(data);
1439 }
1440 
1441 
1442 static int ff_layout_write_done_cb(struct rpc_task *task,
1443 				struct nfs_pgio_header *hdr)
1444 {
1445 	loff_t end_offs = 0;
1446 	int err;
1447 
1448 	trace_nfs4_pnfs_write(hdr, task->tk_status);
1449 	if (task->tk_status < 0)
1450 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1451 					    hdr->args.offset, hdr->args.count,
1452 					    hdr->res.op_status, OP_WRITE,
1453 					    task->tk_status);
1454 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1455 					   hdr->ds_clp, hdr->lseg,
1456 					   hdr->pgio_mirror_idx);
1457 
1458 	switch (err) {
1459 	case -NFS4ERR_RESET_TO_PNFS:
1460 		ff_layout_reset_write(hdr, true);
1461 		return task->tk_status;
1462 	case -NFS4ERR_RESET_TO_MDS:
1463 		ff_layout_reset_write(hdr, false);
1464 		return task->tk_status;
1465 	case -EAGAIN:
1466 		return -EAGAIN;
1467 	}
1468 
1469 	if (hdr->res.verf->committed == NFS_FILE_SYNC ||
1470 	    hdr->res.verf->committed == NFS_DATA_SYNC)
1471 		end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
1472 
1473 	/* Note: if the write is unstable, don't set end_offs until commit */
1474 	ff_layout_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
1475 
1476 	/* zero out fattr since we don't care DS attr at all */
1477 	hdr->fattr.valid = 0;
1478 	if (task->tk_status >= 0)
1479 		nfs_writeback_update_inode(hdr);
1480 
1481 	return 0;
1482 }
1483 
1484 static int ff_layout_commit_done_cb(struct rpc_task *task,
1485 				     struct nfs_commit_data *data)
1486 {
1487 	int err;
1488 
1489 	trace_nfs4_pnfs_commit_ds(data, task->tk_status);
1490 	if (task->tk_status < 0)
1491 		ff_layout_io_track_ds_error(data->lseg, data->ds_commit_index,
1492 					    data->args.offset, data->args.count,
1493 					    data->res.op_status, OP_COMMIT,
1494 					    task->tk_status);
1495 	err = ff_layout_async_handle_error(task, NULL, data->ds_clp,
1496 					   data->lseg, data->ds_commit_index);
1497 
1498 	switch (err) {
1499 	case -NFS4ERR_RESET_TO_PNFS:
1500 		pnfs_generic_prepare_to_resend_writes(data);
1501 		return -EAGAIN;
1502 	case -NFS4ERR_RESET_TO_MDS:
1503 		pnfs_generic_prepare_to_resend_writes(data);
1504 		return -EAGAIN;
1505 	case -EAGAIN:
1506 		rpc_restart_call_prepare(task);
1507 		return -EAGAIN;
1508 	}
1509 
1510 	ff_layout_set_layoutcommit(data->inode, data->lseg, data->lwb);
1511 
1512 	return 0;
1513 }
1514 
1515 static void ff_layout_write_record_layoutstats_start(struct rpc_task *task,
1516 		struct nfs_pgio_header *hdr)
1517 {
1518 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1519 		return;
1520 	nfs4_ff_layout_stat_io_start_write(hdr->inode,
1521 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1522 			hdr->args.count,
1523 			task->tk_start);
1524 }
1525 
1526 static void ff_layout_write_record_layoutstats_done(struct rpc_task *task,
1527 		struct nfs_pgio_header *hdr)
1528 {
1529 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1530 		return;
1531 	nfs4_ff_layout_stat_io_end_write(task,
1532 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1533 			hdr->args.count, hdr->res.count,
1534 			hdr->res.verf->committed);
1535 }
1536 
1537 static int ff_layout_write_prepare_common(struct rpc_task *task,
1538 					  struct nfs_pgio_header *hdr)
1539 {
1540 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1541 		rpc_exit(task, -EIO);
1542 		return -EIO;
1543 	}
1544 
1545 	if (ff_layout_device_unavailable(hdr->lseg, hdr->pgio_mirror_idx)) {
1546 		rpc_exit(task, -EHOSTDOWN);
1547 		return -EAGAIN;
1548 	}
1549 
1550 	ff_layout_write_record_layoutstats_start(task, hdr);
1551 	return 0;
1552 }
1553 
1554 static void ff_layout_write_prepare_v3(struct rpc_task *task, void *data)
1555 {
1556 	struct nfs_pgio_header *hdr = data;
1557 
1558 	if (ff_layout_write_prepare_common(task, hdr))
1559 		return;
1560 
1561 	rpc_call_start(task);
1562 }
1563 
1564 static void ff_layout_write_prepare_v4(struct rpc_task *task, void *data)
1565 {
1566 	struct nfs_pgio_header *hdr = data;
1567 
1568 	if (nfs4_setup_sequence(hdr->ds_clp,
1569 				&hdr->args.seq_args,
1570 				&hdr->res.seq_res,
1571 				task))
1572 		return;
1573 
1574 	if (ff_layout_write_prepare_common(task, hdr))
1575 		return;
1576 
1577 	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
1578 			hdr->args.lock_context, FMODE_WRITE) == -EIO)
1579 		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
1580 }
1581 
1582 static void ff_layout_write_call_done(struct rpc_task *task, void *data)
1583 {
1584 	struct nfs_pgio_header *hdr = data;
1585 
1586 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1587 	    task->tk_status == 0) {
1588 		nfs4_sequence_done(task, &hdr->res.seq_res);
1589 		return;
1590 	}
1591 
1592 	/* Note this may cause RPC to be resent */
1593 	hdr->mds_ops->rpc_call_done(task, hdr);
1594 }
1595 
1596 static void ff_layout_write_count_stats(struct rpc_task *task, void *data)
1597 {
1598 	struct nfs_pgio_header *hdr = data;
1599 
1600 	ff_layout_write_record_layoutstats_done(task, hdr);
1601 	rpc_count_iostats_metrics(task,
1602 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_WRITE]);
1603 }
1604 
1605 static void ff_layout_write_release(void *data)
1606 {
1607 	struct nfs_pgio_header *hdr = data;
1608 
1609 	ff_layout_write_record_layoutstats_done(&hdr->task, hdr);
1610 	pnfs_generic_rw_release(data);
1611 }
1612 
1613 static void ff_layout_commit_record_layoutstats_start(struct rpc_task *task,
1614 		struct nfs_commit_data *cdata)
1615 {
1616 	if (test_and_set_bit(NFS_IOHDR_STAT, &cdata->flags))
1617 		return;
1618 	nfs4_ff_layout_stat_io_start_write(cdata->inode,
1619 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1620 			0, task->tk_start);
1621 }
1622 
1623 static void ff_layout_commit_record_layoutstats_done(struct rpc_task *task,
1624 		struct nfs_commit_data *cdata)
1625 {
1626 	struct nfs_page *req;
1627 	__u64 count = 0;
1628 
1629 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &cdata->flags))
1630 		return;
1631 
1632 	if (task->tk_status == 0) {
1633 		list_for_each_entry(req, &cdata->pages, wb_list)
1634 			count += req->wb_bytes;
1635 	}
1636 	nfs4_ff_layout_stat_io_end_write(task,
1637 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1638 			count, count, NFS_FILE_SYNC);
1639 }
1640 
1641 static void ff_layout_commit_prepare_common(struct rpc_task *task,
1642 		struct nfs_commit_data *cdata)
1643 {
1644 	ff_layout_commit_record_layoutstats_start(task, cdata);
1645 }
1646 
1647 static void ff_layout_commit_prepare_v3(struct rpc_task *task, void *data)
1648 {
1649 	ff_layout_commit_prepare_common(task, data);
1650 	rpc_call_start(task);
1651 }
1652 
1653 static void ff_layout_commit_prepare_v4(struct rpc_task *task, void *data)
1654 {
1655 	struct nfs_commit_data *wdata = data;
1656 
1657 	if (nfs4_setup_sequence(wdata->ds_clp,
1658 				&wdata->args.seq_args,
1659 				&wdata->res.seq_res,
1660 				task))
1661 		return;
1662 	ff_layout_commit_prepare_common(task, data);
1663 }
1664 
1665 static void ff_layout_commit_done(struct rpc_task *task, void *data)
1666 {
1667 	pnfs_generic_write_commit_done(task, data);
1668 }
1669 
1670 static void ff_layout_commit_count_stats(struct rpc_task *task, void *data)
1671 {
1672 	struct nfs_commit_data *cdata = data;
1673 
1674 	ff_layout_commit_record_layoutstats_done(task, cdata);
1675 	rpc_count_iostats_metrics(task,
1676 	    &NFS_CLIENT(cdata->inode)->cl_metrics[NFSPROC4_CLNT_COMMIT]);
1677 }
1678 
1679 static void ff_layout_commit_release(void *data)
1680 {
1681 	struct nfs_commit_data *cdata = data;
1682 
1683 	ff_layout_commit_record_layoutstats_done(&cdata->task, cdata);
1684 	pnfs_generic_commit_release(data);
1685 }
1686 
1687 static const struct rpc_call_ops ff_layout_read_call_ops_v3 = {
1688 	.rpc_call_prepare = ff_layout_read_prepare_v3,
1689 	.rpc_call_done = ff_layout_read_call_done,
1690 	.rpc_count_stats = ff_layout_read_count_stats,
1691 	.rpc_release = ff_layout_read_release,
1692 };
1693 
1694 static const struct rpc_call_ops ff_layout_read_call_ops_v4 = {
1695 	.rpc_call_prepare = ff_layout_read_prepare_v4,
1696 	.rpc_call_done = ff_layout_read_call_done,
1697 	.rpc_count_stats = ff_layout_read_count_stats,
1698 	.rpc_release = ff_layout_read_release,
1699 };
1700 
1701 static const struct rpc_call_ops ff_layout_write_call_ops_v3 = {
1702 	.rpc_call_prepare = ff_layout_write_prepare_v3,
1703 	.rpc_call_done = ff_layout_write_call_done,
1704 	.rpc_count_stats = ff_layout_write_count_stats,
1705 	.rpc_release = ff_layout_write_release,
1706 };
1707 
1708 static const struct rpc_call_ops ff_layout_write_call_ops_v4 = {
1709 	.rpc_call_prepare = ff_layout_write_prepare_v4,
1710 	.rpc_call_done = ff_layout_write_call_done,
1711 	.rpc_count_stats = ff_layout_write_count_stats,
1712 	.rpc_release = ff_layout_write_release,
1713 };
1714 
1715 static const struct rpc_call_ops ff_layout_commit_call_ops_v3 = {
1716 	.rpc_call_prepare = ff_layout_commit_prepare_v3,
1717 	.rpc_call_done = ff_layout_commit_done,
1718 	.rpc_count_stats = ff_layout_commit_count_stats,
1719 	.rpc_release = ff_layout_commit_release,
1720 };
1721 
1722 static const struct rpc_call_ops ff_layout_commit_call_ops_v4 = {
1723 	.rpc_call_prepare = ff_layout_commit_prepare_v4,
1724 	.rpc_call_done = ff_layout_commit_done,
1725 	.rpc_count_stats = ff_layout_commit_count_stats,
1726 	.rpc_release = ff_layout_commit_release,
1727 };
1728 
1729 static enum pnfs_try_status
1730 ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
1731 {
1732 	struct pnfs_layout_segment *lseg = hdr->lseg;
1733 	struct nfs4_pnfs_ds *ds;
1734 	struct rpc_clnt *ds_clnt;
1735 	struct rpc_cred *ds_cred;
1736 	loff_t offset = hdr->args.offset;
1737 	u32 idx = hdr->pgio_mirror_idx;
1738 	int vers;
1739 	struct nfs_fh *fh;
1740 
1741 	dprintk("--> %s ino %lu pgbase %u req %zu@%llu\n",
1742 		__func__, hdr->inode->i_ino,
1743 		hdr->args.pgbase, (size_t)hdr->args.count, offset);
1744 
1745 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, false);
1746 	if (!ds)
1747 		goto out_failed;
1748 
1749 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1750 						   hdr->inode);
1751 	if (IS_ERR(ds_clnt))
1752 		goto out_failed;
1753 
1754 	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
1755 	if (!ds_cred)
1756 		goto out_failed;
1757 
1758 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1759 
1760 	dprintk("%s USE DS: %s cl_count %d vers %d\n", __func__,
1761 		ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count), vers);
1762 
1763 	hdr->pgio_done_cb = ff_layout_read_done_cb;
1764 	atomic_inc(&ds->ds_clp->cl_count);
1765 	hdr->ds_clp = ds->ds_clp;
1766 	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
1767 	if (fh)
1768 		hdr->args.fh = fh;
1769 	/*
1770 	 * Note that if we ever decide to split across DSes,
1771 	 * then we may need to handle dense-like offsets.
1772 	 */
1773 	hdr->args.offset = offset;
1774 	hdr->mds_offset = offset;
1775 
1776 	/* Perform an asynchronous read to ds */
1777 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1778 			  vers == 3 ? &ff_layout_read_call_ops_v3 :
1779 				      &ff_layout_read_call_ops_v4,
1780 			  0, RPC_TASK_SOFTCONN);
1781 	put_rpccred(ds_cred);
1782 	return PNFS_ATTEMPTED;
1783 
1784 out_failed:
1785 	if (ff_layout_avoid_mds_available_ds(lseg))
1786 		return PNFS_TRY_AGAIN;
1787 	return PNFS_NOT_ATTEMPTED;
1788 }
1789 
1790 /* Perform async writes. */
1791 static enum pnfs_try_status
1792 ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
1793 {
1794 	struct pnfs_layout_segment *lseg = hdr->lseg;
1795 	struct nfs4_pnfs_ds *ds;
1796 	struct rpc_clnt *ds_clnt;
1797 	struct rpc_cred *ds_cred;
1798 	loff_t offset = hdr->args.offset;
1799 	int vers;
1800 	struct nfs_fh *fh;
1801 	int idx = hdr->pgio_mirror_idx;
1802 
1803 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
1804 	if (!ds)
1805 		goto out_failed;
1806 
1807 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1808 						   hdr->inode);
1809 	if (IS_ERR(ds_clnt))
1810 		goto out_failed;
1811 
1812 	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
1813 	if (!ds_cred)
1814 		goto out_failed;
1815 
1816 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1817 
1818 	dprintk("%s ino %lu sync %d req %zu@%llu DS: %s cl_count %d vers %d\n",
1819 		__func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
1820 		offset, ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count),
1821 		vers);
1822 
1823 	hdr->pgio_done_cb = ff_layout_write_done_cb;
1824 	atomic_inc(&ds->ds_clp->cl_count);
1825 	hdr->ds_clp = ds->ds_clp;
1826 	hdr->ds_commit_idx = idx;
1827 	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
1828 	if (fh)
1829 		hdr->args.fh = fh;
1830 
1831 	/*
1832 	 * Note that if we ever decide to split across DSes,
1833 	 * then we may need to handle dense-like offsets.
1834 	 */
1835 	hdr->args.offset = offset;
1836 
1837 	/* Perform an asynchronous write */
1838 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1839 			  vers == 3 ? &ff_layout_write_call_ops_v3 :
1840 				      &ff_layout_write_call_ops_v4,
1841 			  sync, RPC_TASK_SOFTCONN);
1842 	put_rpccred(ds_cred);
1843 	return PNFS_ATTEMPTED;
1844 
1845 out_failed:
1846 	if (ff_layout_avoid_mds_available_ds(lseg))
1847 		return PNFS_TRY_AGAIN;
1848 	return PNFS_NOT_ATTEMPTED;
1849 }
1850 
1851 static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1852 {
1853 	return i;
1854 }
1855 
1856 static struct nfs_fh *
1857 select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1858 {
1859 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
1860 
1861 	/* FIXME: Assume that there is only one NFS version available
1862 	 * for the DS.
1863 	 */
1864 	return &flseg->mirror_array[i]->fh_versions[0];
1865 }
1866 
1867 static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
1868 {
1869 	struct pnfs_layout_segment *lseg = data->lseg;
1870 	struct nfs4_pnfs_ds *ds;
1871 	struct rpc_clnt *ds_clnt;
1872 	struct rpc_cred *ds_cred;
1873 	u32 idx;
1874 	int vers, ret;
1875 	struct nfs_fh *fh;
1876 
1877 	idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
1878 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
1879 	if (!ds)
1880 		goto out_err;
1881 
1882 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1883 						   data->inode);
1884 	if (IS_ERR(ds_clnt))
1885 		goto out_err;
1886 
1887 	ds_cred = ff_layout_get_ds_cred(lseg, idx, data->cred);
1888 	if (!ds_cred)
1889 		goto out_err;
1890 
1891 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1892 
1893 	dprintk("%s ino %lu, how %d cl_count %d vers %d\n", __func__,
1894 		data->inode->i_ino, how, atomic_read(&ds->ds_clp->cl_count),
1895 		vers);
1896 	data->commit_done_cb = ff_layout_commit_done_cb;
1897 	data->cred = ds_cred;
1898 	atomic_inc(&ds->ds_clp->cl_count);
1899 	data->ds_clp = ds->ds_clp;
1900 	fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
1901 	if (fh)
1902 		data->args.fh = fh;
1903 
1904 	ret = nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
1905 				   vers == 3 ? &ff_layout_commit_call_ops_v3 :
1906 					       &ff_layout_commit_call_ops_v4,
1907 				   how, RPC_TASK_SOFTCONN);
1908 	put_rpccred(ds_cred);
1909 	return ret;
1910 out_err:
1911 	pnfs_generic_prepare_to_resend_writes(data);
1912 	pnfs_generic_commit_release(data);
1913 	return -EAGAIN;
1914 }
1915 
1916 static int
1917 ff_layout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
1918 			   int how, struct nfs_commit_info *cinfo)
1919 {
1920 	return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
1921 					    ff_layout_initiate_commit);
1922 }
1923 
1924 static struct pnfs_ds_commit_info *
1925 ff_layout_get_ds_info(struct inode *inode)
1926 {
1927 	struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
1928 
1929 	if (layout == NULL)
1930 		return NULL;
1931 
1932 	return &FF_LAYOUT_FROM_HDR(layout)->commit_info;
1933 }
1934 
1935 static void
1936 ff_layout_free_deviceid_node(struct nfs4_deviceid_node *d)
1937 {
1938 	nfs4_ff_layout_free_deviceid(container_of(d, struct nfs4_ff_layout_ds,
1939 						  id_node));
1940 }
1941 
1942 static int ff_layout_encode_ioerr(struct xdr_stream *xdr,
1943 				  const struct nfs4_layoutreturn_args *args,
1944 				  const struct nfs4_flexfile_layoutreturn_args *ff_args)
1945 {
1946 	__be32 *start;
1947 
1948 	start = xdr_reserve_space(xdr, 4);
1949 	if (unlikely(!start))
1950 		return -E2BIG;
1951 
1952 	*start = cpu_to_be32(ff_args->num_errors);
1953 	/* This assume we always return _ALL_ layouts */
1954 	return ff_layout_encode_ds_ioerr(xdr, &ff_args->errors);
1955 }
1956 
1957 static void
1958 encode_opaque_fixed(struct xdr_stream *xdr, const void *buf, size_t len)
1959 {
1960 	WARN_ON_ONCE(xdr_stream_encode_opaque_fixed(xdr, buf, len) < 0);
1961 }
1962 
1963 static void
1964 ff_layout_encode_ff_iostat_head(struct xdr_stream *xdr,
1965 			    const nfs4_stateid *stateid,
1966 			    const struct nfs42_layoutstat_devinfo *devinfo)
1967 {
1968 	__be32 *p;
1969 
1970 	p = xdr_reserve_space(xdr, 8 + 8);
1971 	p = xdr_encode_hyper(p, devinfo->offset);
1972 	p = xdr_encode_hyper(p, devinfo->length);
1973 	encode_opaque_fixed(xdr, stateid->data, NFS4_STATEID_SIZE);
1974 	p = xdr_reserve_space(xdr, 4*8);
1975 	p = xdr_encode_hyper(p, devinfo->read_count);
1976 	p = xdr_encode_hyper(p, devinfo->read_bytes);
1977 	p = xdr_encode_hyper(p, devinfo->write_count);
1978 	p = xdr_encode_hyper(p, devinfo->write_bytes);
1979 	encode_opaque_fixed(xdr, devinfo->dev_id.data, NFS4_DEVICEID4_SIZE);
1980 }
1981 
1982 static void
1983 ff_layout_encode_ff_iostat(struct xdr_stream *xdr,
1984 			    const nfs4_stateid *stateid,
1985 			    const struct nfs42_layoutstat_devinfo *devinfo)
1986 {
1987 	ff_layout_encode_ff_iostat_head(xdr, stateid, devinfo);
1988 	ff_layout_encode_ff_layoutupdate(xdr, devinfo,
1989 			devinfo->ld_private.data);
1990 }
1991 
1992 /* report nothing for now */
1993 static void ff_layout_encode_iostats_array(struct xdr_stream *xdr,
1994 		const struct nfs4_layoutreturn_args *args,
1995 		struct nfs4_flexfile_layoutreturn_args *ff_args)
1996 {
1997 	__be32 *p;
1998 	int i;
1999 
2000 	p = xdr_reserve_space(xdr, 4);
2001 	*p = cpu_to_be32(ff_args->num_dev);
2002 	for (i = 0; i < ff_args->num_dev; i++)
2003 		ff_layout_encode_ff_iostat(xdr,
2004 				&args->layout->plh_stateid,
2005 				&ff_args->devinfo[i]);
2006 }
2007 
2008 static void
2009 ff_layout_free_iostats_array(struct nfs42_layoutstat_devinfo *devinfo,
2010 		unsigned int num_entries)
2011 {
2012 	unsigned int i;
2013 
2014 	for (i = 0; i < num_entries; i++) {
2015 		if (!devinfo[i].ld_private.ops)
2016 			continue;
2017 		if (!devinfo[i].ld_private.ops->free)
2018 			continue;
2019 		devinfo[i].ld_private.ops->free(&devinfo[i].ld_private);
2020 	}
2021 }
2022 
2023 static struct nfs4_deviceid_node *
2024 ff_layout_alloc_deviceid_node(struct nfs_server *server,
2025 			      struct pnfs_device *pdev, gfp_t gfp_flags)
2026 {
2027 	struct nfs4_ff_layout_ds *dsaddr;
2028 
2029 	dsaddr = nfs4_ff_alloc_deviceid_node(server, pdev, gfp_flags);
2030 	if (!dsaddr)
2031 		return NULL;
2032 	return &dsaddr->id_node;
2033 }
2034 
2035 static void
2036 ff_layout_encode_layoutreturn(struct xdr_stream *xdr,
2037 		const void *voidargs,
2038 		const struct nfs4_xdr_opaque_data *ff_opaque)
2039 {
2040 	const struct nfs4_layoutreturn_args *args = voidargs;
2041 	struct nfs4_flexfile_layoutreturn_args *ff_args = ff_opaque->data;
2042 	struct xdr_buf tmp_buf = {
2043 		.head = {
2044 			[0] = {
2045 				.iov_base = page_address(ff_args->pages[0]),
2046 			},
2047 		},
2048 		.buflen = PAGE_SIZE,
2049 	};
2050 	struct xdr_stream tmp_xdr;
2051 	__be32 *start;
2052 
2053 	dprintk("%s: Begin\n", __func__);
2054 
2055 	xdr_init_encode(&tmp_xdr, &tmp_buf, NULL);
2056 
2057 	ff_layout_encode_ioerr(&tmp_xdr, args, ff_args);
2058 	ff_layout_encode_iostats_array(&tmp_xdr, args, ff_args);
2059 
2060 	start = xdr_reserve_space(xdr, 4);
2061 	*start = cpu_to_be32(tmp_buf.len);
2062 	xdr_write_pages(xdr, ff_args->pages, 0, tmp_buf.len);
2063 
2064 	dprintk("%s: Return\n", __func__);
2065 }
2066 
2067 static void
2068 ff_layout_free_layoutreturn(struct nfs4_xdr_opaque_data *args)
2069 {
2070 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2071 
2072 	if (!args->data)
2073 		return;
2074 	ff_args = args->data;
2075 	args->data = NULL;
2076 
2077 	ff_layout_free_ds_ioerr(&ff_args->errors);
2078 	ff_layout_free_iostats_array(ff_args->devinfo, ff_args->num_dev);
2079 
2080 	put_page(ff_args->pages[0]);
2081 	kfree(ff_args);
2082 }
2083 
2084 static const struct nfs4_xdr_opaque_ops layoutreturn_ops = {
2085 	.encode = ff_layout_encode_layoutreturn,
2086 	.free = ff_layout_free_layoutreturn,
2087 };
2088 
2089 static int
2090 ff_layout_prepare_layoutreturn(struct nfs4_layoutreturn_args *args)
2091 {
2092 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2093 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(args->layout);
2094 
2095 	ff_args = kmalloc(sizeof(*ff_args), GFP_KERNEL);
2096 	if (!ff_args)
2097 		goto out_nomem;
2098 	ff_args->pages[0] = alloc_page(GFP_KERNEL);
2099 	if (!ff_args->pages[0])
2100 		goto out_nomem_free;
2101 
2102 	INIT_LIST_HEAD(&ff_args->errors);
2103 	ff_args->num_errors = ff_layout_fetch_ds_ioerr(args->layout,
2104 			&args->range, &ff_args->errors,
2105 			FF_LAYOUTRETURN_MAXERR);
2106 
2107 	spin_lock(&args->inode->i_lock);
2108 	ff_args->num_dev = ff_layout_mirror_prepare_stats(&ff_layout->generic_hdr,
2109 			&ff_args->devinfo[0], ARRAY_SIZE(ff_args->devinfo));
2110 	spin_unlock(&args->inode->i_lock);
2111 
2112 	args->ld_private->ops = &layoutreturn_ops;
2113 	args->ld_private->data = ff_args;
2114 	return 0;
2115 out_nomem_free:
2116 	kfree(ff_args);
2117 out_nomem:
2118 	return -ENOMEM;
2119 }
2120 
2121 static int
2122 ff_layout_ntop4(const struct sockaddr *sap, char *buf, const size_t buflen)
2123 {
2124 	const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
2125 
2126 	return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
2127 }
2128 
2129 static size_t
2130 ff_layout_ntop6_noscopeid(const struct sockaddr *sap, char *buf,
2131 			  const int buflen)
2132 {
2133 	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
2134 	const struct in6_addr *addr = &sin6->sin6_addr;
2135 
2136 	/*
2137 	 * RFC 4291, Section 2.2.2
2138 	 *
2139 	 * Shorthanded ANY address
2140 	 */
2141 	if (ipv6_addr_any(addr))
2142 		return snprintf(buf, buflen, "::");
2143 
2144 	/*
2145 	 * RFC 4291, Section 2.2.2
2146 	 *
2147 	 * Shorthanded loopback address
2148 	 */
2149 	if (ipv6_addr_loopback(addr))
2150 		return snprintf(buf, buflen, "::1");
2151 
2152 	/*
2153 	 * RFC 4291, Section 2.2.3
2154 	 *
2155 	 * Special presentation address format for mapped v4
2156 	 * addresses.
2157 	 */
2158 	if (ipv6_addr_v4mapped(addr))
2159 		return snprintf(buf, buflen, "::ffff:%pI4",
2160 					&addr->s6_addr32[3]);
2161 
2162 	/*
2163 	 * RFC 4291, Section 2.2.1
2164 	 */
2165 	return snprintf(buf, buflen, "%pI6c", addr);
2166 }
2167 
2168 /* Derived from rpc_sockaddr2uaddr */
2169 static void
2170 ff_layout_encode_netaddr(struct xdr_stream *xdr, struct nfs4_pnfs_ds_addr *da)
2171 {
2172 	struct sockaddr *sap = (struct sockaddr *)&da->da_addr;
2173 	char portbuf[RPCBIND_MAXUADDRPLEN];
2174 	char addrbuf[RPCBIND_MAXUADDRLEN];
2175 	char *netid;
2176 	unsigned short port;
2177 	int len, netid_len;
2178 	__be32 *p;
2179 
2180 	switch (sap->sa_family) {
2181 	case AF_INET:
2182 		if (ff_layout_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
2183 			return;
2184 		port = ntohs(((struct sockaddr_in *)sap)->sin_port);
2185 		netid = "tcp";
2186 		netid_len = 3;
2187 		break;
2188 	case AF_INET6:
2189 		if (ff_layout_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
2190 			return;
2191 		port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
2192 		netid = "tcp6";
2193 		netid_len = 4;
2194 		break;
2195 	default:
2196 		/* we only support tcp and tcp6 */
2197 		WARN_ON_ONCE(1);
2198 		return;
2199 	}
2200 
2201 	snprintf(portbuf, sizeof(portbuf), ".%u.%u", port >> 8, port & 0xff);
2202 	len = strlcat(addrbuf, portbuf, sizeof(addrbuf));
2203 
2204 	p = xdr_reserve_space(xdr, 4 + netid_len);
2205 	xdr_encode_opaque(p, netid, netid_len);
2206 
2207 	p = xdr_reserve_space(xdr, 4 + len);
2208 	xdr_encode_opaque(p, addrbuf, len);
2209 }
2210 
2211 static void
2212 ff_layout_encode_nfstime(struct xdr_stream *xdr,
2213 			 ktime_t t)
2214 {
2215 	struct timespec64 ts;
2216 	__be32 *p;
2217 
2218 	p = xdr_reserve_space(xdr, 12);
2219 	ts = ktime_to_timespec64(t);
2220 	p = xdr_encode_hyper(p, ts.tv_sec);
2221 	*p++ = cpu_to_be32(ts.tv_nsec);
2222 }
2223 
2224 static void
2225 ff_layout_encode_io_latency(struct xdr_stream *xdr,
2226 			    struct nfs4_ff_io_stat *stat)
2227 {
2228 	__be32 *p;
2229 
2230 	p = xdr_reserve_space(xdr, 5 * 8);
2231 	p = xdr_encode_hyper(p, stat->ops_requested);
2232 	p = xdr_encode_hyper(p, stat->bytes_requested);
2233 	p = xdr_encode_hyper(p, stat->ops_completed);
2234 	p = xdr_encode_hyper(p, stat->bytes_completed);
2235 	p = xdr_encode_hyper(p, stat->bytes_not_delivered);
2236 	ff_layout_encode_nfstime(xdr, stat->total_busy_time);
2237 	ff_layout_encode_nfstime(xdr, stat->aggregate_completion_time);
2238 }
2239 
2240 static void
2241 ff_layout_encode_ff_layoutupdate(struct xdr_stream *xdr,
2242 			      const struct nfs42_layoutstat_devinfo *devinfo,
2243 			      struct nfs4_ff_layout_mirror *mirror)
2244 {
2245 	struct nfs4_pnfs_ds_addr *da;
2246 	struct nfs4_pnfs_ds *ds = mirror->mirror_ds->ds;
2247 	struct nfs_fh *fh = &mirror->fh_versions[0];
2248 	__be32 *p;
2249 
2250 	da = list_first_entry(&ds->ds_addrs, struct nfs4_pnfs_ds_addr, da_node);
2251 	dprintk("%s: DS %s: encoding address %s\n",
2252 		__func__, ds->ds_remotestr, da->da_remotestr);
2253 	/* netaddr4 */
2254 	ff_layout_encode_netaddr(xdr, da);
2255 	/* nfs_fh4 */
2256 	p = xdr_reserve_space(xdr, 4 + fh->size);
2257 	xdr_encode_opaque(p, fh->data, fh->size);
2258 	/* ff_io_latency4 read */
2259 	spin_lock(&mirror->lock);
2260 	ff_layout_encode_io_latency(xdr, &mirror->read_stat.io_stat);
2261 	/* ff_io_latency4 write */
2262 	ff_layout_encode_io_latency(xdr, &mirror->write_stat.io_stat);
2263 	spin_unlock(&mirror->lock);
2264 	/* nfstime4 */
2265 	ff_layout_encode_nfstime(xdr, ktime_sub(ktime_get(), mirror->start_time));
2266 	/* bool */
2267 	p = xdr_reserve_space(xdr, 4);
2268 	*p = cpu_to_be32(false);
2269 }
2270 
2271 static void
2272 ff_layout_encode_layoutstats(struct xdr_stream *xdr, const void *args,
2273 			     const struct nfs4_xdr_opaque_data *opaque)
2274 {
2275 	struct nfs42_layoutstat_devinfo *devinfo = container_of(opaque,
2276 			struct nfs42_layoutstat_devinfo, ld_private);
2277 	__be32 *start;
2278 
2279 	/* layoutupdate length */
2280 	start = xdr_reserve_space(xdr, 4);
2281 	ff_layout_encode_ff_layoutupdate(xdr, devinfo, opaque->data);
2282 
2283 	*start = cpu_to_be32((xdr->p - start - 1) * 4);
2284 }
2285 
2286 static void
2287 ff_layout_free_layoutstats(struct nfs4_xdr_opaque_data *opaque)
2288 {
2289 	struct nfs4_ff_layout_mirror *mirror = opaque->data;
2290 
2291 	ff_layout_put_mirror(mirror);
2292 }
2293 
2294 static const struct nfs4_xdr_opaque_ops layoutstat_ops = {
2295 	.encode = ff_layout_encode_layoutstats,
2296 	.free	= ff_layout_free_layoutstats,
2297 };
2298 
2299 static int
2300 ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
2301 			       struct nfs42_layoutstat_devinfo *devinfo,
2302 			       int dev_limit)
2303 {
2304 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
2305 	struct nfs4_ff_layout_mirror *mirror;
2306 	struct nfs4_deviceid_node *dev;
2307 	int i = 0;
2308 
2309 	list_for_each_entry(mirror, &ff_layout->mirrors, mirrors) {
2310 		if (i >= dev_limit)
2311 			break;
2312 		if (IS_ERR_OR_NULL(mirror->mirror_ds))
2313 			continue;
2314 		if (!test_and_clear_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags))
2315 			continue;
2316 		/* mirror refcount put in cleanup_layoutstats */
2317 		if (!atomic_inc_not_zero(&mirror->ref))
2318 			continue;
2319 		dev = &mirror->mirror_ds->id_node;
2320 		memcpy(&devinfo->dev_id, &dev->deviceid, NFS4_DEVICEID4_SIZE);
2321 		devinfo->offset = 0;
2322 		devinfo->length = NFS4_MAX_UINT64;
2323 		spin_lock(&mirror->lock);
2324 		devinfo->read_count = mirror->read_stat.io_stat.ops_completed;
2325 		devinfo->read_bytes = mirror->read_stat.io_stat.bytes_completed;
2326 		devinfo->write_count = mirror->write_stat.io_stat.ops_completed;
2327 		devinfo->write_bytes = mirror->write_stat.io_stat.bytes_completed;
2328 		spin_unlock(&mirror->lock);
2329 		devinfo->layout_type = LAYOUT_FLEX_FILES;
2330 		devinfo->ld_private.ops = &layoutstat_ops;
2331 		devinfo->ld_private.data = mirror;
2332 
2333 		devinfo++;
2334 		i++;
2335 	}
2336 	return i;
2337 }
2338 
2339 static int
2340 ff_layout_prepare_layoutstats(struct nfs42_layoutstat_args *args)
2341 {
2342 	struct nfs4_flexfile_layout *ff_layout;
2343 	const int dev_count = PNFS_LAYOUTSTATS_MAXDEV;
2344 
2345 	/* For now, send at most PNFS_LAYOUTSTATS_MAXDEV statistics */
2346 	args->devinfo = kmalloc_array(dev_count, sizeof(*args->devinfo), GFP_NOIO);
2347 	if (!args->devinfo)
2348 		return -ENOMEM;
2349 
2350 	spin_lock(&args->inode->i_lock);
2351 	ff_layout = FF_LAYOUT_FROM_HDR(NFS_I(args->inode)->layout);
2352 	args->num_dev = ff_layout_mirror_prepare_stats(&ff_layout->generic_hdr,
2353 			&args->devinfo[0], dev_count);
2354 	spin_unlock(&args->inode->i_lock);
2355 	if (!args->num_dev) {
2356 		kfree(args->devinfo);
2357 		args->devinfo = NULL;
2358 		return -ENOENT;
2359 	}
2360 
2361 	return 0;
2362 }
2363 
2364 static int
2365 ff_layout_set_layoutdriver(struct nfs_server *server,
2366 		const struct nfs_fh *dummy)
2367 {
2368 #if IS_ENABLED(CONFIG_NFS_V4_2)
2369 	server->caps |= NFS_CAP_LAYOUTSTATS;
2370 #endif
2371 	return 0;
2372 }
2373 
2374 static struct pnfs_layoutdriver_type flexfilelayout_type = {
2375 	.id			= LAYOUT_FLEX_FILES,
2376 	.name			= "LAYOUT_FLEX_FILES",
2377 	.owner			= THIS_MODULE,
2378 	.set_layoutdriver	= ff_layout_set_layoutdriver,
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