xref: /openbmc/linux/fs/nfs/flexfilelayout/flexfilelayout.c (revision 943126417891372d56aa3fe46295cbf53db31370)
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 (refcount_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 		refcount_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 && refcount_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 		rc = -EIO;
458 		p = xdr_inline_decode(&stream, 4);
459 		if (!p)
460 			goto out_err_free;
461 		fh_count = be32_to_cpup(p);
462 
463 		fls->mirror_array[i]->fh_versions =
464 			kcalloc(fh_count, sizeof(struct nfs_fh),
465 				gfp_flags);
466 		if (fls->mirror_array[i]->fh_versions == NULL) {
467 			rc = -ENOMEM;
468 			goto out_err_free;
469 		}
470 
471 		for (j = 0; j < fh_count; j++) {
472 			rc = decode_nfs_fh(&stream,
473 					   &fls->mirror_array[i]->fh_versions[j]);
474 			if (rc)
475 				goto out_err_free;
476 		}
477 
478 		fls->mirror_array[i]->fh_versions_cnt = fh_count;
479 
480 		/* user */
481 		rc = decode_name(&stream, &id);
482 		if (rc)
483 			goto out_err_free;
484 
485 		acred.uid = make_kuid(&init_user_ns, id);
486 
487 		/* group */
488 		rc = decode_name(&stream, &id);
489 		if (rc)
490 			goto out_err_free;
491 
492 		acred.gid = make_kgid(&init_user_ns, id);
493 
494 		/* find the cred for it */
495 		rcu_assign_pointer(cred, rpc_lookup_generic_cred(&acred, 0, gfp_flags));
496 		if (IS_ERR(cred)) {
497 			rc = PTR_ERR(cred);
498 			goto out_err_free;
499 		}
500 
501 		if (lgr->range.iomode == IOMODE_READ)
502 			rcu_assign_pointer(fls->mirror_array[i]->ro_cred, cred);
503 		else
504 			rcu_assign_pointer(fls->mirror_array[i]->rw_cred, cred);
505 
506 		mirror = ff_layout_add_mirror(lh, fls->mirror_array[i]);
507 		if (mirror != fls->mirror_array[i]) {
508 			/* swap cred ptrs so free_mirror will clean up old */
509 			if (lgr->range.iomode == IOMODE_READ) {
510 				cred = xchg(&mirror->ro_cred, cred);
511 				rcu_assign_pointer(fls->mirror_array[i]->ro_cred, cred);
512 			} else {
513 				cred = xchg(&mirror->rw_cred, cred);
514 				rcu_assign_pointer(fls->mirror_array[i]->rw_cred, cred);
515 			}
516 			ff_layout_free_mirror(fls->mirror_array[i]);
517 			fls->mirror_array[i] = mirror;
518 		}
519 
520 		dprintk("%s: iomode %s uid %u gid %u\n", __func__,
521 			lgr->range.iomode == IOMODE_READ ? "READ" : "RW",
522 			from_kuid(&init_user_ns, acred.uid),
523 			from_kgid(&init_user_ns, acred.gid));
524 	}
525 
526 	p = xdr_inline_decode(&stream, 4);
527 	if (!p)
528 		goto out_sort_mirrors;
529 	fls->flags = be32_to_cpup(p);
530 
531 	p = xdr_inline_decode(&stream, 4);
532 	if (!p)
533 		goto out_sort_mirrors;
534 	for (i=0; i < fls->mirror_array_cnt; i++)
535 		fls->mirror_array[i]->report_interval = be32_to_cpup(p);
536 
537 out_sort_mirrors:
538 	ff_layout_sort_mirrors(fls);
539 	rc = ff_layout_check_layout(lgr);
540 	if (rc)
541 		goto out_err_free;
542 	ret = &fls->generic_hdr;
543 	dprintk("<-- %s (success)\n", __func__);
544 out_free_page:
545 	__free_page(scratch);
546 	return ret;
547 out_err_free:
548 	_ff_layout_free_lseg(fls);
549 	ret = ERR_PTR(rc);
550 	dprintk("<-- %s (%d)\n", __func__, rc);
551 	goto out_free_page;
552 }
553 
554 static bool ff_layout_has_rw_segments(struct pnfs_layout_hdr *layout)
555 {
556 	struct pnfs_layout_segment *lseg;
557 
558 	list_for_each_entry(lseg, &layout->plh_segs, pls_list)
559 		if (lseg->pls_range.iomode == IOMODE_RW)
560 			return true;
561 
562 	return false;
563 }
564 
565 static void
566 ff_layout_free_lseg(struct pnfs_layout_segment *lseg)
567 {
568 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
569 
570 	dprintk("--> %s\n", __func__);
571 
572 	if (lseg->pls_range.iomode == IOMODE_RW) {
573 		struct nfs4_flexfile_layout *ffl;
574 		struct inode *inode;
575 
576 		ffl = FF_LAYOUT_FROM_HDR(lseg->pls_layout);
577 		inode = ffl->generic_hdr.plh_inode;
578 		spin_lock(&inode->i_lock);
579 		if (!ff_layout_has_rw_segments(lseg->pls_layout)) {
580 			ffl->commit_info.nbuckets = 0;
581 			kfree(ffl->commit_info.buckets);
582 			ffl->commit_info.buckets = NULL;
583 		}
584 		spin_unlock(&inode->i_lock);
585 	}
586 	_ff_layout_free_lseg(fls);
587 }
588 
589 /* Return 1 until we have multiple lsegs support */
590 static int
591 ff_layout_get_lseg_count(struct nfs4_ff_layout_segment *fls)
592 {
593 	return 1;
594 }
595 
596 static void
597 nfs4_ff_start_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
598 {
599 	/* first IO request? */
600 	if (atomic_inc_return(&timer->n_ops) == 1) {
601 		timer->start_time = now;
602 	}
603 }
604 
605 static ktime_t
606 nfs4_ff_end_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
607 {
608 	ktime_t start;
609 
610 	if (atomic_dec_return(&timer->n_ops) < 0)
611 		WARN_ON_ONCE(1);
612 
613 	start = timer->start_time;
614 	timer->start_time = now;
615 	return ktime_sub(now, start);
616 }
617 
618 static bool
619 nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_mirror *mirror,
620 			    struct nfs4_ff_layoutstat *layoutstat,
621 			    ktime_t now)
622 {
623 	s64 report_interval = FF_LAYOUTSTATS_REPORT_INTERVAL;
624 	struct nfs4_flexfile_layout *ffl = FF_LAYOUT_FROM_HDR(mirror->layout);
625 
626 	nfs4_ff_start_busy_timer(&layoutstat->busy_timer, now);
627 	if (!mirror->start_time)
628 		mirror->start_time = now;
629 	if (mirror->report_interval != 0)
630 		report_interval = (s64)mirror->report_interval * 1000LL;
631 	else if (layoutstats_timer != 0)
632 		report_interval = (s64)layoutstats_timer * 1000LL;
633 	if (ktime_to_ms(ktime_sub(now, ffl->last_report_time)) >=
634 			report_interval) {
635 		ffl->last_report_time = now;
636 		return true;
637 	}
638 
639 	return false;
640 }
641 
642 static void
643 nfs4_ff_layout_stat_io_update_requested(struct nfs4_ff_layoutstat *layoutstat,
644 		__u64 requested)
645 {
646 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
647 
648 	iostat->ops_requested++;
649 	iostat->bytes_requested += requested;
650 }
651 
652 static void
653 nfs4_ff_layout_stat_io_update_completed(struct nfs4_ff_layoutstat *layoutstat,
654 		__u64 requested,
655 		__u64 completed,
656 		ktime_t time_completed,
657 		ktime_t time_started)
658 {
659 	struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
660 	ktime_t completion_time = ktime_sub(time_completed, time_started);
661 	ktime_t timer;
662 
663 	iostat->ops_completed++;
664 	iostat->bytes_completed += completed;
665 	iostat->bytes_not_delivered += requested - completed;
666 
667 	timer = nfs4_ff_end_busy_timer(&layoutstat->busy_timer, time_completed);
668 	iostat->total_busy_time =
669 			ktime_add(iostat->total_busy_time, timer);
670 	iostat->aggregate_completion_time =
671 			ktime_add(iostat->aggregate_completion_time,
672 					completion_time);
673 }
674 
675 static void
676 nfs4_ff_layout_stat_io_start_read(struct inode *inode,
677 		struct nfs4_ff_layout_mirror *mirror,
678 		__u64 requested, ktime_t now)
679 {
680 	bool report;
681 
682 	spin_lock(&mirror->lock);
683 	report = nfs4_ff_layoutstat_start_io(mirror, &mirror->read_stat, now);
684 	nfs4_ff_layout_stat_io_update_requested(&mirror->read_stat, requested);
685 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
686 	spin_unlock(&mirror->lock);
687 
688 	if (report)
689 		pnfs_report_layoutstat(inode, GFP_KERNEL);
690 }
691 
692 static void
693 nfs4_ff_layout_stat_io_end_read(struct rpc_task *task,
694 		struct nfs4_ff_layout_mirror *mirror,
695 		__u64 requested,
696 		__u64 completed)
697 {
698 	spin_lock(&mirror->lock);
699 	nfs4_ff_layout_stat_io_update_completed(&mirror->read_stat,
700 			requested, completed,
701 			ktime_get(), task->tk_start);
702 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
703 	spin_unlock(&mirror->lock);
704 }
705 
706 static void
707 nfs4_ff_layout_stat_io_start_write(struct inode *inode,
708 		struct nfs4_ff_layout_mirror *mirror,
709 		__u64 requested, ktime_t now)
710 {
711 	bool report;
712 
713 	spin_lock(&mirror->lock);
714 	report = nfs4_ff_layoutstat_start_io(mirror , &mirror->write_stat, now);
715 	nfs4_ff_layout_stat_io_update_requested(&mirror->write_stat, requested);
716 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
717 	spin_unlock(&mirror->lock);
718 
719 	if (report)
720 		pnfs_report_layoutstat(inode, GFP_NOIO);
721 }
722 
723 static void
724 nfs4_ff_layout_stat_io_end_write(struct rpc_task *task,
725 		struct nfs4_ff_layout_mirror *mirror,
726 		__u64 requested,
727 		__u64 completed,
728 		enum nfs3_stable_how committed)
729 {
730 	if (committed == NFS_UNSTABLE)
731 		requested = completed = 0;
732 
733 	spin_lock(&mirror->lock);
734 	nfs4_ff_layout_stat_io_update_completed(&mirror->write_stat,
735 			requested, completed, ktime_get(), task->tk_start);
736 	set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
737 	spin_unlock(&mirror->lock);
738 }
739 
740 static int
741 ff_layout_alloc_commit_info(struct pnfs_layout_segment *lseg,
742 			    struct nfs_commit_info *cinfo,
743 			    gfp_t gfp_flags)
744 {
745 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
746 	struct pnfs_commit_bucket *buckets;
747 	int size;
748 
749 	if (cinfo->ds->nbuckets != 0) {
750 		/* This assumes there is only one RW lseg per file.
751 		 * To support multiple lseg per file, we need to
752 		 * change struct pnfs_commit_bucket to allow dynamic
753 		 * increasing nbuckets.
754 		 */
755 		return 0;
756 	}
757 
758 	size = ff_layout_get_lseg_count(fls) * FF_LAYOUT_MIRROR_COUNT(lseg);
759 
760 	buckets = kcalloc(size, sizeof(struct pnfs_commit_bucket),
761 			  gfp_flags);
762 	if (!buckets)
763 		return -ENOMEM;
764 	else {
765 		int i;
766 
767 		spin_lock(&cinfo->inode->i_lock);
768 		if (cinfo->ds->nbuckets != 0)
769 			kfree(buckets);
770 		else {
771 			cinfo->ds->buckets = buckets;
772 			cinfo->ds->nbuckets = size;
773 			for (i = 0; i < size; i++) {
774 				INIT_LIST_HEAD(&buckets[i].written);
775 				INIT_LIST_HEAD(&buckets[i].committing);
776 				/* mark direct verifier as unset */
777 				buckets[i].direct_verf.committed =
778 					NFS_INVALID_STABLE_HOW;
779 			}
780 		}
781 		spin_unlock(&cinfo->inode->i_lock);
782 		return 0;
783 	}
784 }
785 
786 static struct nfs4_pnfs_ds *
787 ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg,
788 				  int start_idx,
789 				  int *best_idx)
790 {
791 	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
792 	struct nfs4_pnfs_ds *ds;
793 	bool fail_return = false;
794 	int idx;
795 
796 	/* mirrors are sorted by efficiency */
797 	for (idx = start_idx; idx < fls->mirror_array_cnt; idx++) {
798 		if (idx+1 == fls->mirror_array_cnt)
799 			fail_return = true;
800 		ds = nfs4_ff_layout_prepare_ds(lseg, idx, fail_return);
801 		if (ds) {
802 			*best_idx = idx;
803 			return ds;
804 		}
805 	}
806 
807 	return NULL;
808 }
809 
810 static void
811 ff_layout_pg_get_read(struct nfs_pageio_descriptor *pgio,
812 		      struct nfs_page *req,
813 		      bool strict_iomode)
814 {
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 
829 static void
830 ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
831 			struct nfs_page *req)
832 {
833 	struct nfs_pgio_mirror *pgm;
834 	struct nfs4_ff_layout_mirror *mirror;
835 	struct nfs4_pnfs_ds *ds;
836 	int ds_idx;
837 
838 retry:
839 	pnfs_generic_pg_check_layout(pgio);
840 	/* Use full layout for now */
841 	if (!pgio->pg_lseg) {
842 		ff_layout_pg_get_read(pgio, req, false);
843 		if (!pgio->pg_lseg)
844 			goto out_nolseg;
845 	}
846 	if (ff_layout_avoid_read_on_rw(pgio->pg_lseg)) {
847 		ff_layout_pg_get_read(pgio, req, true);
848 		if (!pgio->pg_lseg)
849 			goto out_nolseg;
850 	}
851 
852 	ds = ff_layout_choose_best_ds_for_read(pgio->pg_lseg, 0, &ds_idx);
853 	if (!ds) {
854 		if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
855 			goto out_mds;
856 		pnfs_put_lseg(pgio->pg_lseg);
857 		pgio->pg_lseg = NULL;
858 		/* Sleep for 1 second before retrying */
859 		ssleep(1);
860 		goto retry;
861 	}
862 
863 	mirror = FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx);
864 
865 	pgio->pg_mirror_idx = ds_idx;
866 
867 	/* read always uses only one mirror - idx 0 for pgio layer */
868 	pgm = &pgio->pg_mirrors[0];
869 	pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].rsize;
870 
871 	return;
872 out_nolseg:
873 	if (pgio->pg_error < 0)
874 		return;
875 out_mds:
876 	pnfs_put_lseg(pgio->pg_lseg);
877 	pgio->pg_lseg = NULL;
878 	nfs_pageio_reset_read_mds(pgio);
879 }
880 
881 static void
882 ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
883 			struct nfs_page *req)
884 {
885 	struct nfs4_ff_layout_mirror *mirror;
886 	struct nfs_pgio_mirror *pgm;
887 	struct nfs_commit_info cinfo;
888 	struct nfs4_pnfs_ds *ds;
889 	int i;
890 	int status;
891 
892 retry:
893 	pnfs_generic_pg_check_layout(pgio);
894 	if (!pgio->pg_lseg) {
895 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
896 						   req->wb_context,
897 						   0,
898 						   NFS4_MAX_UINT64,
899 						   IOMODE_RW,
900 						   false,
901 						   GFP_NOFS);
902 		if (IS_ERR(pgio->pg_lseg)) {
903 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
904 			pgio->pg_lseg = NULL;
905 			return;
906 		}
907 	}
908 	/* If no lseg, fall back to write through mds */
909 	if (pgio->pg_lseg == NULL)
910 		goto out_mds;
911 
912 	nfs_init_cinfo(&cinfo, pgio->pg_inode, pgio->pg_dreq);
913 	status = ff_layout_alloc_commit_info(pgio->pg_lseg, &cinfo, GFP_NOFS);
914 	if (status < 0)
915 		goto out_mds;
916 
917 	/* Use a direct mapping of ds_idx to pgio mirror_idx */
918 	if (WARN_ON_ONCE(pgio->pg_mirror_count !=
919 	    FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg)))
920 		goto out_mds;
921 
922 	for (i = 0; i < pgio->pg_mirror_count; i++) {
923 		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, i, true);
924 		if (!ds) {
925 			if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
926 				goto out_mds;
927 			pnfs_put_lseg(pgio->pg_lseg);
928 			pgio->pg_lseg = NULL;
929 			/* Sleep for 1 second before retrying */
930 			ssleep(1);
931 			goto retry;
932 		}
933 		pgm = &pgio->pg_mirrors[i];
934 		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
935 		pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].wsize;
936 	}
937 
938 	return;
939 
940 out_mds:
941 	pnfs_put_lseg(pgio->pg_lseg);
942 	pgio->pg_lseg = NULL;
943 	nfs_pageio_reset_write_mds(pgio);
944 }
945 
946 static unsigned int
947 ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
948 				    struct nfs_page *req)
949 {
950 	if (!pgio->pg_lseg) {
951 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
952 						   req->wb_context,
953 						   0,
954 						   NFS4_MAX_UINT64,
955 						   IOMODE_RW,
956 						   false,
957 						   GFP_NOFS);
958 		if (IS_ERR(pgio->pg_lseg)) {
959 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
960 			pgio->pg_lseg = NULL;
961 			goto out;
962 		}
963 	}
964 	if (pgio->pg_lseg)
965 		return FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg);
966 
967 	/* no lseg means that pnfs is not in use, so no mirroring here */
968 	nfs_pageio_reset_write_mds(pgio);
969 out:
970 	return 1;
971 }
972 
973 static const struct nfs_pageio_ops ff_layout_pg_read_ops = {
974 	.pg_init = ff_layout_pg_init_read,
975 	.pg_test = pnfs_generic_pg_test,
976 	.pg_doio = pnfs_generic_pg_readpages,
977 	.pg_cleanup = pnfs_generic_pg_cleanup,
978 };
979 
980 static const struct nfs_pageio_ops ff_layout_pg_write_ops = {
981 	.pg_init = ff_layout_pg_init_write,
982 	.pg_test = pnfs_generic_pg_test,
983 	.pg_doio = pnfs_generic_pg_writepages,
984 	.pg_get_mirror_count = ff_layout_pg_get_mirror_count_write,
985 	.pg_cleanup = pnfs_generic_pg_cleanup,
986 };
987 
988 static void ff_layout_reset_write(struct nfs_pgio_header *hdr, bool retry_pnfs)
989 {
990 	struct rpc_task *task = &hdr->task;
991 
992 	pnfs_layoutcommit_inode(hdr->inode, false);
993 
994 	if (retry_pnfs) {
995 		dprintk("%s Reset task %5u for i/o through pNFS "
996 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
997 			hdr->task.tk_pid,
998 			hdr->inode->i_sb->s_id,
999 			(unsigned long long)NFS_FILEID(hdr->inode),
1000 			hdr->args.count,
1001 			(unsigned long long)hdr->args.offset);
1002 
1003 		hdr->completion_ops->reschedule_io(hdr);
1004 		return;
1005 	}
1006 
1007 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1008 		dprintk("%s Reset task %5u for i/o through MDS "
1009 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1010 			hdr->task.tk_pid,
1011 			hdr->inode->i_sb->s_id,
1012 			(unsigned long long)NFS_FILEID(hdr->inode),
1013 			hdr->args.count,
1014 			(unsigned long long)hdr->args.offset);
1015 
1016 		task->tk_status = pnfs_write_done_resend_to_mds(hdr);
1017 	}
1018 }
1019 
1020 static void ff_layout_reset_read(struct nfs_pgio_header *hdr)
1021 {
1022 	struct rpc_task *task = &hdr->task;
1023 
1024 	pnfs_layoutcommit_inode(hdr->inode, false);
1025 
1026 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1027 		dprintk("%s Reset task %5u for i/o through MDS "
1028 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1029 			hdr->task.tk_pid,
1030 			hdr->inode->i_sb->s_id,
1031 			(unsigned long long)NFS_FILEID(hdr->inode),
1032 			hdr->args.count,
1033 			(unsigned long long)hdr->args.offset);
1034 
1035 		task->tk_status = pnfs_read_done_resend_to_mds(hdr);
1036 	}
1037 }
1038 
1039 static int ff_layout_async_handle_error_v4(struct rpc_task *task,
1040 					   struct nfs4_state *state,
1041 					   struct nfs_client *clp,
1042 					   struct pnfs_layout_segment *lseg,
1043 					   int idx)
1044 {
1045 	struct pnfs_layout_hdr *lo = lseg->pls_layout;
1046 	struct inode *inode = lo->plh_inode;
1047 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1048 	struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
1049 
1050 	switch (task->tk_status) {
1051 	case -NFS4ERR_BADSESSION:
1052 	case -NFS4ERR_BADSLOT:
1053 	case -NFS4ERR_BAD_HIGH_SLOT:
1054 	case -NFS4ERR_DEADSESSION:
1055 	case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
1056 	case -NFS4ERR_SEQ_FALSE_RETRY:
1057 	case -NFS4ERR_SEQ_MISORDERED:
1058 		dprintk("%s ERROR %d, Reset session. Exchangeid "
1059 			"flags 0x%x\n", __func__, task->tk_status,
1060 			clp->cl_exchange_flags);
1061 		nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
1062 		break;
1063 	case -NFS4ERR_DELAY:
1064 	case -NFS4ERR_GRACE:
1065 		rpc_delay(task, FF_LAYOUT_POLL_RETRY_MAX);
1066 		break;
1067 	case -NFS4ERR_RETRY_UNCACHED_REP:
1068 		break;
1069 	/* Invalidate Layout errors */
1070 	case -NFS4ERR_PNFS_NO_LAYOUT:
1071 	case -ESTALE:           /* mapped NFS4ERR_STALE */
1072 	case -EBADHANDLE:       /* mapped NFS4ERR_BADHANDLE */
1073 	case -EISDIR:           /* mapped NFS4ERR_ISDIR */
1074 	case -NFS4ERR_FHEXPIRED:
1075 	case -NFS4ERR_WRONG_TYPE:
1076 		dprintk("%s Invalid layout error %d\n", __func__,
1077 			task->tk_status);
1078 		/*
1079 		 * Destroy layout so new i/o will get a new layout.
1080 		 * Layout will not be destroyed until all current lseg
1081 		 * references are put. Mark layout as invalid to resend failed
1082 		 * i/o and all i/o waiting on the slot table to the MDS until
1083 		 * layout is destroyed and a new valid layout is obtained.
1084 		 */
1085 		pnfs_destroy_layout(NFS_I(inode));
1086 		rpc_wake_up(&tbl->slot_tbl_waitq);
1087 		goto reset;
1088 	/* RPC connection errors */
1089 	case -ECONNREFUSED:
1090 	case -EHOSTDOWN:
1091 	case -EHOSTUNREACH:
1092 	case -ENETUNREACH:
1093 	case -EIO:
1094 	case -ETIMEDOUT:
1095 	case -EPIPE:
1096 		dprintk("%s DS connection error %d\n", __func__,
1097 			task->tk_status);
1098 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1099 				&devid->deviceid);
1100 		rpc_wake_up(&tbl->slot_tbl_waitq);
1101 		/* fall through */
1102 	default:
1103 		if (ff_layout_avoid_mds_available_ds(lseg))
1104 			return -NFS4ERR_RESET_TO_PNFS;
1105 reset:
1106 		dprintk("%s Retry through MDS. Error %d\n", __func__,
1107 			task->tk_status);
1108 		return -NFS4ERR_RESET_TO_MDS;
1109 	}
1110 	task->tk_status = 0;
1111 	return -EAGAIN;
1112 }
1113 
1114 /* Retry all errors through either pNFS or MDS except for -EJUKEBOX */
1115 static int ff_layout_async_handle_error_v3(struct rpc_task *task,
1116 					   struct pnfs_layout_segment *lseg,
1117 					   int idx)
1118 {
1119 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1120 
1121 	switch (task->tk_status) {
1122 	/* File access problems. Don't mark the device as unavailable */
1123 	case -EACCES:
1124 	case -ESTALE:
1125 	case -EISDIR:
1126 	case -EBADHANDLE:
1127 	case -ELOOP:
1128 	case -ENOSPC:
1129 		break;
1130 	case -EJUKEBOX:
1131 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1132 		goto out_retry;
1133 	default:
1134 		dprintk("%s DS connection error %d\n", __func__,
1135 			task->tk_status);
1136 		nfs4_delete_deviceid(devid->ld, devid->nfs_client,
1137 				&devid->deviceid);
1138 	}
1139 	/* FIXME: Need to prevent infinite looping here. */
1140 	return -NFS4ERR_RESET_TO_PNFS;
1141 out_retry:
1142 	task->tk_status = 0;
1143 	rpc_restart_call_prepare(task);
1144 	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
1145 	return -EAGAIN;
1146 }
1147 
1148 static int ff_layout_async_handle_error(struct rpc_task *task,
1149 					struct nfs4_state *state,
1150 					struct nfs_client *clp,
1151 					struct pnfs_layout_segment *lseg,
1152 					int idx)
1153 {
1154 	int vers = clp->cl_nfs_mod->rpc_vers->number;
1155 
1156 	if (task->tk_status >= 0)
1157 		return 0;
1158 
1159 	/* Handle the case of an invalid layout segment */
1160 	if (!pnfs_is_valid_lseg(lseg))
1161 		return -NFS4ERR_RESET_TO_PNFS;
1162 
1163 	switch (vers) {
1164 	case 3:
1165 		return ff_layout_async_handle_error_v3(task, lseg, idx);
1166 	case 4:
1167 		return ff_layout_async_handle_error_v4(task, state, clp,
1168 						       lseg, idx);
1169 	default:
1170 		/* should never happen */
1171 		WARN_ON_ONCE(1);
1172 		return 0;
1173 	}
1174 }
1175 
1176 static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg,
1177 					int idx, u64 offset, u64 length,
1178 					u32 status, int opnum, int error)
1179 {
1180 	struct nfs4_ff_layout_mirror *mirror;
1181 	int err;
1182 
1183 	if (status == 0) {
1184 		switch (error) {
1185 		case -ETIMEDOUT:
1186 		case -EPFNOSUPPORT:
1187 		case -EPROTONOSUPPORT:
1188 		case -EOPNOTSUPP:
1189 		case -ECONNREFUSED:
1190 		case -ECONNRESET:
1191 		case -EHOSTDOWN:
1192 		case -EHOSTUNREACH:
1193 		case -ENETUNREACH:
1194 		case -EADDRINUSE:
1195 		case -ENOBUFS:
1196 		case -EPIPE:
1197 		case -EPERM:
1198 			status = NFS4ERR_NXIO;
1199 			break;
1200 		case -EACCES:
1201 			status = NFS4ERR_ACCESS;
1202 			break;
1203 		default:
1204 			return;
1205 		}
1206 	}
1207 
1208 	switch (status) {
1209 	case NFS4ERR_DELAY:
1210 	case NFS4ERR_GRACE:
1211 		return;
1212 	default:
1213 		break;
1214 	}
1215 
1216 	mirror = FF_LAYOUT_COMP(lseg, idx);
1217 	err = ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),
1218 				       mirror, offset, length, status, opnum,
1219 				       GFP_NOIO);
1220 	pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode, lseg);
1221 	dprintk("%s: err %d op %d status %u\n", __func__, err, opnum, status);
1222 }
1223 
1224 /* NFS_PROTO call done callback routines */
1225 static int ff_layout_read_done_cb(struct rpc_task *task,
1226 				struct nfs_pgio_header *hdr)
1227 {
1228 	int err;
1229 
1230 	trace_nfs4_pnfs_read(hdr, task->tk_status);
1231 	if (task->tk_status < 0)
1232 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1233 					    hdr->args.offset, hdr->args.count,
1234 					    hdr->res.op_status, OP_READ,
1235 					    task->tk_status);
1236 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1237 					   hdr->ds_clp, hdr->lseg,
1238 					   hdr->pgio_mirror_idx);
1239 
1240 	clear_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1241 	clear_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1242 	switch (err) {
1243 	case -NFS4ERR_RESET_TO_PNFS:
1244 		if (ff_layout_choose_best_ds_for_read(hdr->lseg,
1245 					hdr->pgio_mirror_idx + 1,
1246 					&hdr->pgio_mirror_idx))
1247 			goto out_eagain;
1248 		set_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1249 		return task->tk_status;
1250 	case -NFS4ERR_RESET_TO_MDS:
1251 		set_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1252 		return task->tk_status;
1253 	case -EAGAIN:
1254 		goto out_eagain;
1255 	}
1256 
1257 	return 0;
1258 out_eagain:
1259 	rpc_restart_call_prepare(task);
1260 	return -EAGAIN;
1261 }
1262 
1263 static bool
1264 ff_layout_need_layoutcommit(struct pnfs_layout_segment *lseg)
1265 {
1266 	return !(FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_LAYOUTCOMMIT);
1267 }
1268 
1269 /*
1270  * We reference the rpc_cred of the first WRITE that triggers the need for
1271  * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
1272  * rfc5661 is not clear about which credential should be used.
1273  *
1274  * Flexlayout client should treat DS replied FILE_SYNC as DATA_SYNC, so
1275  * to follow http://www.rfc-editor.org/errata_search.php?rfc=5661&eid=2751
1276  * we always send layoutcommit after DS writes.
1277  */
1278 static void
1279 ff_layout_set_layoutcommit(struct inode *inode,
1280 		struct pnfs_layout_segment *lseg,
1281 		loff_t end_offset)
1282 {
1283 	if (!ff_layout_need_layoutcommit(lseg))
1284 		return;
1285 
1286 	pnfs_set_layoutcommit(inode, lseg, end_offset);
1287 	dprintk("%s inode %lu pls_end_pos %llu\n", __func__, inode->i_ino,
1288 		(unsigned long long) NFS_I(inode)->layout->plh_lwb);
1289 }
1290 
1291 static bool
1292 ff_layout_device_unavailable(struct pnfs_layout_segment *lseg, int idx)
1293 {
1294 	/* No mirroring for now */
1295 	struct nfs4_deviceid_node *node = FF_LAYOUT_DEVID_NODE(lseg, idx);
1296 
1297 	return ff_layout_test_devid_unavailable(node);
1298 }
1299 
1300 static void ff_layout_read_record_layoutstats_start(struct rpc_task *task,
1301 		struct nfs_pgio_header *hdr)
1302 {
1303 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1304 		return;
1305 	nfs4_ff_layout_stat_io_start_read(hdr->inode,
1306 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1307 			hdr->args.count,
1308 			task->tk_start);
1309 }
1310 
1311 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
1312 		struct nfs_pgio_header *hdr)
1313 {
1314 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1315 		return;
1316 	nfs4_ff_layout_stat_io_end_read(task,
1317 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1318 			hdr->args.count,
1319 			hdr->res.count);
1320 	set_bit(NFS_LSEG_LAYOUTRETURN, &hdr->lseg->pls_flags);
1321 }
1322 
1323 static int ff_layout_read_prepare_common(struct rpc_task *task,
1324 					 struct nfs_pgio_header *hdr)
1325 {
1326 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1327 		rpc_exit(task, -EIO);
1328 		return -EIO;
1329 	}
1330 	if (ff_layout_device_unavailable(hdr->lseg, hdr->pgio_mirror_idx)) {
1331 		rpc_exit(task, -EHOSTDOWN);
1332 		return -EAGAIN;
1333 	}
1334 
1335 	ff_layout_read_record_layoutstats_start(task, hdr);
1336 	return 0;
1337 }
1338 
1339 /*
1340  * Call ops for the async read/write cases
1341  * In the case of dense layouts, the offset needs to be reset to its
1342  * original value.
1343  */
1344 static void ff_layout_read_prepare_v3(struct rpc_task *task, void *data)
1345 {
1346 	struct nfs_pgio_header *hdr = data;
1347 
1348 	if (ff_layout_read_prepare_common(task, hdr))
1349 		return;
1350 
1351 	rpc_call_start(task);
1352 }
1353 
1354 static void ff_layout_read_prepare_v4(struct rpc_task *task, void *data)
1355 {
1356 	struct nfs_pgio_header *hdr = data;
1357 
1358 	if (nfs4_setup_sequence(hdr->ds_clp,
1359 				&hdr->args.seq_args,
1360 				&hdr->res.seq_res,
1361 				task))
1362 		return;
1363 
1364 	if (ff_layout_read_prepare_common(task, hdr))
1365 		return;
1366 
1367 	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
1368 			hdr->args.lock_context, FMODE_READ) == -EIO)
1369 		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
1370 }
1371 
1372 static void ff_layout_read_call_done(struct rpc_task *task, void *data)
1373 {
1374 	struct nfs_pgio_header *hdr = data;
1375 
1376 	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
1377 
1378 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1379 	    task->tk_status == 0) {
1380 		nfs4_sequence_done(task, &hdr->res.seq_res);
1381 		return;
1382 	}
1383 
1384 	/* Note this may cause RPC to be resent */
1385 	hdr->mds_ops->rpc_call_done(task, hdr);
1386 }
1387 
1388 static void ff_layout_read_count_stats(struct rpc_task *task, void *data)
1389 {
1390 	struct nfs_pgio_header *hdr = data;
1391 
1392 	ff_layout_read_record_layoutstats_done(task, hdr);
1393 	rpc_count_iostats_metrics(task,
1394 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_READ]);
1395 }
1396 
1397 static void ff_layout_read_release(void *data)
1398 {
1399 	struct nfs_pgio_header *hdr = data;
1400 
1401 	ff_layout_read_record_layoutstats_done(&hdr->task, hdr);
1402 	if (test_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags))
1403 		pnfs_read_resend_pnfs(hdr);
1404 	else if (test_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags))
1405 		ff_layout_reset_read(hdr);
1406 	pnfs_generic_rw_release(data);
1407 }
1408 
1409 
1410 static int ff_layout_write_done_cb(struct rpc_task *task,
1411 				struct nfs_pgio_header *hdr)
1412 {
1413 	loff_t end_offs = 0;
1414 	int err;
1415 
1416 	trace_nfs4_pnfs_write(hdr, task->tk_status);
1417 	if (task->tk_status < 0)
1418 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1419 					    hdr->args.offset, hdr->args.count,
1420 					    hdr->res.op_status, OP_WRITE,
1421 					    task->tk_status);
1422 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1423 					   hdr->ds_clp, hdr->lseg,
1424 					   hdr->pgio_mirror_idx);
1425 
1426 	clear_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1427 	clear_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1428 	switch (err) {
1429 	case -NFS4ERR_RESET_TO_PNFS:
1430 		set_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags);
1431 		return task->tk_status;
1432 	case -NFS4ERR_RESET_TO_MDS:
1433 		set_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags);
1434 		return task->tk_status;
1435 	case -EAGAIN:
1436 		return -EAGAIN;
1437 	}
1438 
1439 	if (hdr->res.verf->committed == NFS_FILE_SYNC ||
1440 	    hdr->res.verf->committed == NFS_DATA_SYNC)
1441 		end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
1442 
1443 	/* Note: if the write is unstable, don't set end_offs until commit */
1444 	ff_layout_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
1445 
1446 	/* zero out fattr since we don't care DS attr at all */
1447 	hdr->fattr.valid = 0;
1448 	if (task->tk_status >= 0)
1449 		nfs_writeback_update_inode(hdr);
1450 
1451 	return 0;
1452 }
1453 
1454 static int ff_layout_commit_done_cb(struct rpc_task *task,
1455 				     struct nfs_commit_data *data)
1456 {
1457 	int err;
1458 
1459 	trace_nfs4_pnfs_commit_ds(data, task->tk_status);
1460 	if (task->tk_status < 0)
1461 		ff_layout_io_track_ds_error(data->lseg, data->ds_commit_index,
1462 					    data->args.offset, data->args.count,
1463 					    data->res.op_status, OP_COMMIT,
1464 					    task->tk_status);
1465 	err = ff_layout_async_handle_error(task, NULL, data->ds_clp,
1466 					   data->lseg, data->ds_commit_index);
1467 
1468 	switch (err) {
1469 	case -NFS4ERR_RESET_TO_PNFS:
1470 		pnfs_generic_prepare_to_resend_writes(data);
1471 		return -EAGAIN;
1472 	case -NFS4ERR_RESET_TO_MDS:
1473 		pnfs_generic_prepare_to_resend_writes(data);
1474 		return -EAGAIN;
1475 	case -EAGAIN:
1476 		rpc_restart_call_prepare(task);
1477 		return -EAGAIN;
1478 	}
1479 
1480 	ff_layout_set_layoutcommit(data->inode, data->lseg, data->lwb);
1481 
1482 	return 0;
1483 }
1484 
1485 static void ff_layout_write_record_layoutstats_start(struct rpc_task *task,
1486 		struct nfs_pgio_header *hdr)
1487 {
1488 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1489 		return;
1490 	nfs4_ff_layout_stat_io_start_write(hdr->inode,
1491 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1492 			hdr->args.count,
1493 			task->tk_start);
1494 }
1495 
1496 static void ff_layout_write_record_layoutstats_done(struct rpc_task *task,
1497 		struct nfs_pgio_header *hdr)
1498 {
1499 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1500 		return;
1501 	nfs4_ff_layout_stat_io_end_write(task,
1502 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1503 			hdr->args.count, hdr->res.count,
1504 			hdr->res.verf->committed);
1505 	set_bit(NFS_LSEG_LAYOUTRETURN, &hdr->lseg->pls_flags);
1506 }
1507 
1508 static int ff_layout_write_prepare_common(struct rpc_task *task,
1509 					  struct nfs_pgio_header *hdr)
1510 {
1511 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1512 		rpc_exit(task, -EIO);
1513 		return -EIO;
1514 	}
1515 
1516 	if (ff_layout_device_unavailable(hdr->lseg, hdr->pgio_mirror_idx)) {
1517 		rpc_exit(task, -EHOSTDOWN);
1518 		return -EAGAIN;
1519 	}
1520 
1521 	ff_layout_write_record_layoutstats_start(task, hdr);
1522 	return 0;
1523 }
1524 
1525 static void ff_layout_write_prepare_v3(struct rpc_task *task, void *data)
1526 {
1527 	struct nfs_pgio_header *hdr = data;
1528 
1529 	if (ff_layout_write_prepare_common(task, hdr))
1530 		return;
1531 
1532 	rpc_call_start(task);
1533 }
1534 
1535 static void ff_layout_write_prepare_v4(struct rpc_task *task, void *data)
1536 {
1537 	struct nfs_pgio_header *hdr = data;
1538 
1539 	if (nfs4_setup_sequence(hdr->ds_clp,
1540 				&hdr->args.seq_args,
1541 				&hdr->res.seq_res,
1542 				task))
1543 		return;
1544 
1545 	if (ff_layout_write_prepare_common(task, hdr))
1546 		return;
1547 
1548 	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
1549 			hdr->args.lock_context, FMODE_WRITE) == -EIO)
1550 		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
1551 }
1552 
1553 static void ff_layout_write_call_done(struct rpc_task *task, void *data)
1554 {
1555 	struct nfs_pgio_header *hdr = data;
1556 
1557 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1558 	    task->tk_status == 0) {
1559 		nfs4_sequence_done(task, &hdr->res.seq_res);
1560 		return;
1561 	}
1562 
1563 	/* Note this may cause RPC to be resent */
1564 	hdr->mds_ops->rpc_call_done(task, hdr);
1565 }
1566 
1567 static void ff_layout_write_count_stats(struct rpc_task *task, void *data)
1568 {
1569 	struct nfs_pgio_header *hdr = data;
1570 
1571 	ff_layout_write_record_layoutstats_done(task, hdr);
1572 	rpc_count_iostats_metrics(task,
1573 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_WRITE]);
1574 }
1575 
1576 static void ff_layout_write_release(void *data)
1577 {
1578 	struct nfs_pgio_header *hdr = data;
1579 
1580 	ff_layout_write_record_layoutstats_done(&hdr->task, hdr);
1581 	if (test_bit(NFS_IOHDR_RESEND_PNFS, &hdr->flags))
1582 		ff_layout_reset_write(hdr, true);
1583 	else if (test_bit(NFS_IOHDR_RESEND_MDS, &hdr->flags))
1584 		ff_layout_reset_write(hdr, false);
1585 	pnfs_generic_rw_release(data);
1586 }
1587 
1588 static void ff_layout_commit_record_layoutstats_start(struct rpc_task *task,
1589 		struct nfs_commit_data *cdata)
1590 {
1591 	if (test_and_set_bit(NFS_IOHDR_STAT, &cdata->flags))
1592 		return;
1593 	nfs4_ff_layout_stat_io_start_write(cdata->inode,
1594 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1595 			0, task->tk_start);
1596 }
1597 
1598 static void ff_layout_commit_record_layoutstats_done(struct rpc_task *task,
1599 		struct nfs_commit_data *cdata)
1600 {
1601 	struct nfs_page *req;
1602 	__u64 count = 0;
1603 
1604 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &cdata->flags))
1605 		return;
1606 
1607 	if (task->tk_status == 0) {
1608 		list_for_each_entry(req, &cdata->pages, wb_list)
1609 			count += req->wb_bytes;
1610 	}
1611 	nfs4_ff_layout_stat_io_end_write(task,
1612 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1613 			count, count, NFS_FILE_SYNC);
1614 	set_bit(NFS_LSEG_LAYOUTRETURN, &cdata->lseg->pls_flags);
1615 }
1616 
1617 static void ff_layout_commit_prepare_common(struct rpc_task *task,
1618 		struct nfs_commit_data *cdata)
1619 {
1620 	ff_layout_commit_record_layoutstats_start(task, cdata);
1621 }
1622 
1623 static void ff_layout_commit_prepare_v3(struct rpc_task *task, void *data)
1624 {
1625 	ff_layout_commit_prepare_common(task, data);
1626 	rpc_call_start(task);
1627 }
1628 
1629 static void ff_layout_commit_prepare_v4(struct rpc_task *task, void *data)
1630 {
1631 	struct nfs_commit_data *wdata = data;
1632 
1633 	if (nfs4_setup_sequence(wdata->ds_clp,
1634 				&wdata->args.seq_args,
1635 				&wdata->res.seq_res,
1636 				task))
1637 		return;
1638 	ff_layout_commit_prepare_common(task, data);
1639 }
1640 
1641 static void ff_layout_commit_done(struct rpc_task *task, void *data)
1642 {
1643 	pnfs_generic_write_commit_done(task, data);
1644 }
1645 
1646 static void ff_layout_commit_count_stats(struct rpc_task *task, void *data)
1647 {
1648 	struct nfs_commit_data *cdata = data;
1649 
1650 	ff_layout_commit_record_layoutstats_done(task, cdata);
1651 	rpc_count_iostats_metrics(task,
1652 	    &NFS_CLIENT(cdata->inode)->cl_metrics[NFSPROC4_CLNT_COMMIT]);
1653 }
1654 
1655 static void ff_layout_commit_release(void *data)
1656 {
1657 	struct nfs_commit_data *cdata = data;
1658 
1659 	ff_layout_commit_record_layoutstats_done(&cdata->task, cdata);
1660 	pnfs_generic_commit_release(data);
1661 }
1662 
1663 static const struct rpc_call_ops ff_layout_read_call_ops_v3 = {
1664 	.rpc_call_prepare = ff_layout_read_prepare_v3,
1665 	.rpc_call_done = ff_layout_read_call_done,
1666 	.rpc_count_stats = ff_layout_read_count_stats,
1667 	.rpc_release = ff_layout_read_release,
1668 };
1669 
1670 static const struct rpc_call_ops ff_layout_read_call_ops_v4 = {
1671 	.rpc_call_prepare = ff_layout_read_prepare_v4,
1672 	.rpc_call_done = ff_layout_read_call_done,
1673 	.rpc_count_stats = ff_layout_read_count_stats,
1674 	.rpc_release = ff_layout_read_release,
1675 };
1676 
1677 static const struct rpc_call_ops ff_layout_write_call_ops_v3 = {
1678 	.rpc_call_prepare = ff_layout_write_prepare_v3,
1679 	.rpc_call_done = ff_layout_write_call_done,
1680 	.rpc_count_stats = ff_layout_write_count_stats,
1681 	.rpc_release = ff_layout_write_release,
1682 };
1683 
1684 static const struct rpc_call_ops ff_layout_write_call_ops_v4 = {
1685 	.rpc_call_prepare = ff_layout_write_prepare_v4,
1686 	.rpc_call_done = ff_layout_write_call_done,
1687 	.rpc_count_stats = ff_layout_write_count_stats,
1688 	.rpc_release = ff_layout_write_release,
1689 };
1690 
1691 static const struct rpc_call_ops ff_layout_commit_call_ops_v3 = {
1692 	.rpc_call_prepare = ff_layout_commit_prepare_v3,
1693 	.rpc_call_done = ff_layout_commit_done,
1694 	.rpc_count_stats = ff_layout_commit_count_stats,
1695 	.rpc_release = ff_layout_commit_release,
1696 };
1697 
1698 static const struct rpc_call_ops ff_layout_commit_call_ops_v4 = {
1699 	.rpc_call_prepare = ff_layout_commit_prepare_v4,
1700 	.rpc_call_done = ff_layout_commit_done,
1701 	.rpc_count_stats = ff_layout_commit_count_stats,
1702 	.rpc_release = ff_layout_commit_release,
1703 };
1704 
1705 static enum pnfs_try_status
1706 ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
1707 {
1708 	struct pnfs_layout_segment *lseg = hdr->lseg;
1709 	struct nfs4_pnfs_ds *ds;
1710 	struct rpc_clnt *ds_clnt;
1711 	struct rpc_cred *ds_cred;
1712 	loff_t offset = hdr->args.offset;
1713 	u32 idx = hdr->pgio_mirror_idx;
1714 	int vers;
1715 	struct nfs_fh *fh;
1716 
1717 	dprintk("--> %s ino %lu pgbase %u req %zu@%llu\n",
1718 		__func__, hdr->inode->i_ino,
1719 		hdr->args.pgbase, (size_t)hdr->args.count, offset);
1720 
1721 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, false);
1722 	if (!ds)
1723 		goto out_failed;
1724 
1725 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1726 						   hdr->inode);
1727 	if (IS_ERR(ds_clnt))
1728 		goto out_failed;
1729 
1730 	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
1731 	if (!ds_cred)
1732 		goto out_failed;
1733 
1734 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1735 
1736 	dprintk("%s USE DS: %s cl_count %d vers %d\n", __func__,
1737 		ds->ds_remotestr, refcount_read(&ds->ds_clp->cl_count), vers);
1738 
1739 	hdr->pgio_done_cb = ff_layout_read_done_cb;
1740 	refcount_inc(&ds->ds_clp->cl_count);
1741 	hdr->ds_clp = ds->ds_clp;
1742 	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
1743 	if (fh)
1744 		hdr->args.fh = fh;
1745 	/*
1746 	 * Note that if we ever decide to split across DSes,
1747 	 * then we may need to handle dense-like offsets.
1748 	 */
1749 	hdr->args.offset = offset;
1750 	hdr->mds_offset = offset;
1751 
1752 	/* Perform an asynchronous read to ds */
1753 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1754 			  vers == 3 ? &ff_layout_read_call_ops_v3 :
1755 				      &ff_layout_read_call_ops_v4,
1756 			  0, RPC_TASK_SOFTCONN);
1757 	put_rpccred(ds_cred);
1758 	return PNFS_ATTEMPTED;
1759 
1760 out_failed:
1761 	if (ff_layout_avoid_mds_available_ds(lseg))
1762 		return PNFS_TRY_AGAIN;
1763 	return PNFS_NOT_ATTEMPTED;
1764 }
1765 
1766 /* Perform async writes. */
1767 static enum pnfs_try_status
1768 ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
1769 {
1770 	struct pnfs_layout_segment *lseg = hdr->lseg;
1771 	struct nfs4_pnfs_ds *ds;
1772 	struct rpc_clnt *ds_clnt;
1773 	struct rpc_cred *ds_cred;
1774 	loff_t offset = hdr->args.offset;
1775 	int vers;
1776 	struct nfs_fh *fh;
1777 	int idx = hdr->pgio_mirror_idx;
1778 
1779 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
1780 	if (!ds)
1781 		goto out_failed;
1782 
1783 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1784 						   hdr->inode);
1785 	if (IS_ERR(ds_clnt))
1786 		goto out_failed;
1787 
1788 	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
1789 	if (!ds_cred)
1790 		goto out_failed;
1791 
1792 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1793 
1794 	dprintk("%s ino %lu sync %d req %zu@%llu DS: %s cl_count %d vers %d\n",
1795 		__func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
1796 		offset, ds->ds_remotestr, refcount_read(&ds->ds_clp->cl_count),
1797 		vers);
1798 
1799 	hdr->pgio_done_cb = ff_layout_write_done_cb;
1800 	refcount_inc(&ds->ds_clp->cl_count);
1801 	hdr->ds_clp = ds->ds_clp;
1802 	hdr->ds_commit_idx = idx;
1803 	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
1804 	if (fh)
1805 		hdr->args.fh = fh;
1806 
1807 	/*
1808 	 * Note that if we ever decide to split across DSes,
1809 	 * then we may need to handle dense-like offsets.
1810 	 */
1811 	hdr->args.offset = offset;
1812 
1813 	/* Perform an asynchronous write */
1814 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1815 			  vers == 3 ? &ff_layout_write_call_ops_v3 :
1816 				      &ff_layout_write_call_ops_v4,
1817 			  sync, RPC_TASK_SOFTCONN);
1818 	put_rpccred(ds_cred);
1819 	return PNFS_ATTEMPTED;
1820 
1821 out_failed:
1822 	if (ff_layout_avoid_mds_available_ds(lseg))
1823 		return PNFS_TRY_AGAIN;
1824 	return PNFS_NOT_ATTEMPTED;
1825 }
1826 
1827 static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1828 {
1829 	return i;
1830 }
1831 
1832 static struct nfs_fh *
1833 select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1834 {
1835 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
1836 
1837 	/* FIXME: Assume that there is only one NFS version available
1838 	 * for the DS.
1839 	 */
1840 	return &flseg->mirror_array[i]->fh_versions[0];
1841 }
1842 
1843 static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
1844 {
1845 	struct pnfs_layout_segment *lseg = data->lseg;
1846 	struct nfs4_pnfs_ds *ds;
1847 	struct rpc_clnt *ds_clnt;
1848 	struct rpc_cred *ds_cred;
1849 	u32 idx;
1850 	int vers, ret;
1851 	struct nfs_fh *fh;
1852 
1853 	if (!lseg || !(pnfs_is_valid_lseg(lseg) ||
1854 	    test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags)))
1855 		goto out_err;
1856 
1857 	idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
1858 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
1859 	if (!ds)
1860 		goto out_err;
1861 
1862 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1863 						   data->inode);
1864 	if (IS_ERR(ds_clnt))
1865 		goto out_err;
1866 
1867 	ds_cred = ff_layout_get_ds_cred(lseg, idx, data->cred);
1868 	if (!ds_cred)
1869 		goto out_err;
1870 
1871 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1872 
1873 	dprintk("%s ino %lu, how %d cl_count %d vers %d\n", __func__,
1874 		data->inode->i_ino, how, refcount_read(&ds->ds_clp->cl_count),
1875 		vers);
1876 	data->commit_done_cb = ff_layout_commit_done_cb;
1877 	data->cred = ds_cred;
1878 	refcount_inc(&ds->ds_clp->cl_count);
1879 	data->ds_clp = ds->ds_clp;
1880 	fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
1881 	if (fh)
1882 		data->args.fh = fh;
1883 
1884 	ret = nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
1885 				   vers == 3 ? &ff_layout_commit_call_ops_v3 :
1886 					       &ff_layout_commit_call_ops_v4,
1887 				   how, RPC_TASK_SOFTCONN);
1888 	put_rpccred(ds_cred);
1889 	return ret;
1890 out_err:
1891 	pnfs_generic_prepare_to_resend_writes(data);
1892 	pnfs_generic_commit_release(data);
1893 	return -EAGAIN;
1894 }
1895 
1896 static int
1897 ff_layout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
1898 			   int how, struct nfs_commit_info *cinfo)
1899 {
1900 	return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
1901 					    ff_layout_initiate_commit);
1902 }
1903 
1904 static struct pnfs_ds_commit_info *
1905 ff_layout_get_ds_info(struct inode *inode)
1906 {
1907 	struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
1908 
1909 	if (layout == NULL)
1910 		return NULL;
1911 
1912 	return &FF_LAYOUT_FROM_HDR(layout)->commit_info;
1913 }
1914 
1915 static void
1916 ff_layout_free_deviceid_node(struct nfs4_deviceid_node *d)
1917 {
1918 	nfs4_ff_layout_free_deviceid(container_of(d, struct nfs4_ff_layout_ds,
1919 						  id_node));
1920 }
1921 
1922 static int ff_layout_encode_ioerr(struct xdr_stream *xdr,
1923 				  const struct nfs4_layoutreturn_args *args,
1924 				  const struct nfs4_flexfile_layoutreturn_args *ff_args)
1925 {
1926 	__be32 *start;
1927 
1928 	start = xdr_reserve_space(xdr, 4);
1929 	if (unlikely(!start))
1930 		return -E2BIG;
1931 
1932 	*start = cpu_to_be32(ff_args->num_errors);
1933 	/* This assume we always return _ALL_ layouts */
1934 	return ff_layout_encode_ds_ioerr(xdr, &ff_args->errors);
1935 }
1936 
1937 static void
1938 encode_opaque_fixed(struct xdr_stream *xdr, const void *buf, size_t len)
1939 {
1940 	WARN_ON_ONCE(xdr_stream_encode_opaque_fixed(xdr, buf, len) < 0);
1941 }
1942 
1943 static void
1944 ff_layout_encode_ff_iostat_head(struct xdr_stream *xdr,
1945 			    const nfs4_stateid *stateid,
1946 			    const struct nfs42_layoutstat_devinfo *devinfo)
1947 {
1948 	__be32 *p;
1949 
1950 	p = xdr_reserve_space(xdr, 8 + 8);
1951 	p = xdr_encode_hyper(p, devinfo->offset);
1952 	p = xdr_encode_hyper(p, devinfo->length);
1953 	encode_opaque_fixed(xdr, stateid->data, NFS4_STATEID_SIZE);
1954 	p = xdr_reserve_space(xdr, 4*8);
1955 	p = xdr_encode_hyper(p, devinfo->read_count);
1956 	p = xdr_encode_hyper(p, devinfo->read_bytes);
1957 	p = xdr_encode_hyper(p, devinfo->write_count);
1958 	p = xdr_encode_hyper(p, devinfo->write_bytes);
1959 	encode_opaque_fixed(xdr, devinfo->dev_id.data, NFS4_DEVICEID4_SIZE);
1960 }
1961 
1962 static void
1963 ff_layout_encode_ff_iostat(struct xdr_stream *xdr,
1964 			    const nfs4_stateid *stateid,
1965 			    const struct nfs42_layoutstat_devinfo *devinfo)
1966 {
1967 	ff_layout_encode_ff_iostat_head(xdr, stateid, devinfo);
1968 	ff_layout_encode_ff_layoutupdate(xdr, devinfo,
1969 			devinfo->ld_private.data);
1970 }
1971 
1972 /* report nothing for now */
1973 static void ff_layout_encode_iostats_array(struct xdr_stream *xdr,
1974 		const struct nfs4_layoutreturn_args *args,
1975 		struct nfs4_flexfile_layoutreturn_args *ff_args)
1976 {
1977 	__be32 *p;
1978 	int i;
1979 
1980 	p = xdr_reserve_space(xdr, 4);
1981 	*p = cpu_to_be32(ff_args->num_dev);
1982 	for (i = 0; i < ff_args->num_dev; i++)
1983 		ff_layout_encode_ff_iostat(xdr,
1984 				&args->layout->plh_stateid,
1985 				&ff_args->devinfo[i]);
1986 }
1987 
1988 static void
1989 ff_layout_free_iostats_array(struct nfs42_layoutstat_devinfo *devinfo,
1990 		unsigned int num_entries)
1991 {
1992 	unsigned int i;
1993 
1994 	for (i = 0; i < num_entries; i++) {
1995 		if (!devinfo[i].ld_private.ops)
1996 			continue;
1997 		if (!devinfo[i].ld_private.ops->free)
1998 			continue;
1999 		devinfo[i].ld_private.ops->free(&devinfo[i].ld_private);
2000 	}
2001 }
2002 
2003 static struct nfs4_deviceid_node *
2004 ff_layout_alloc_deviceid_node(struct nfs_server *server,
2005 			      struct pnfs_device *pdev, gfp_t gfp_flags)
2006 {
2007 	struct nfs4_ff_layout_ds *dsaddr;
2008 
2009 	dsaddr = nfs4_ff_alloc_deviceid_node(server, pdev, gfp_flags);
2010 	if (!dsaddr)
2011 		return NULL;
2012 	return &dsaddr->id_node;
2013 }
2014 
2015 static void
2016 ff_layout_encode_layoutreturn(struct xdr_stream *xdr,
2017 		const void *voidargs,
2018 		const struct nfs4_xdr_opaque_data *ff_opaque)
2019 {
2020 	const struct nfs4_layoutreturn_args *args = voidargs;
2021 	struct nfs4_flexfile_layoutreturn_args *ff_args = ff_opaque->data;
2022 	struct xdr_buf tmp_buf = {
2023 		.head = {
2024 			[0] = {
2025 				.iov_base = page_address(ff_args->pages[0]),
2026 			},
2027 		},
2028 		.buflen = PAGE_SIZE,
2029 	};
2030 	struct xdr_stream tmp_xdr;
2031 	__be32 *start;
2032 
2033 	dprintk("%s: Begin\n", __func__);
2034 
2035 	xdr_init_encode(&tmp_xdr, &tmp_buf, NULL);
2036 
2037 	ff_layout_encode_ioerr(&tmp_xdr, args, ff_args);
2038 	ff_layout_encode_iostats_array(&tmp_xdr, args, ff_args);
2039 
2040 	start = xdr_reserve_space(xdr, 4);
2041 	*start = cpu_to_be32(tmp_buf.len);
2042 	xdr_write_pages(xdr, ff_args->pages, 0, tmp_buf.len);
2043 
2044 	dprintk("%s: Return\n", __func__);
2045 }
2046 
2047 static void
2048 ff_layout_free_layoutreturn(struct nfs4_xdr_opaque_data *args)
2049 {
2050 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2051 
2052 	if (!args->data)
2053 		return;
2054 	ff_args = args->data;
2055 	args->data = NULL;
2056 
2057 	ff_layout_free_ds_ioerr(&ff_args->errors);
2058 	ff_layout_free_iostats_array(ff_args->devinfo, ff_args->num_dev);
2059 
2060 	put_page(ff_args->pages[0]);
2061 	kfree(ff_args);
2062 }
2063 
2064 static const struct nfs4_xdr_opaque_ops layoutreturn_ops = {
2065 	.encode = ff_layout_encode_layoutreturn,
2066 	.free = ff_layout_free_layoutreturn,
2067 };
2068 
2069 static int
2070 ff_layout_prepare_layoutreturn(struct nfs4_layoutreturn_args *args)
2071 {
2072 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2073 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(args->layout);
2074 
2075 	ff_args = kmalloc(sizeof(*ff_args), GFP_KERNEL);
2076 	if (!ff_args)
2077 		goto out_nomem;
2078 	ff_args->pages[0] = alloc_page(GFP_KERNEL);
2079 	if (!ff_args->pages[0])
2080 		goto out_nomem_free;
2081 
2082 	INIT_LIST_HEAD(&ff_args->errors);
2083 	ff_args->num_errors = ff_layout_fetch_ds_ioerr(args->layout,
2084 			&args->range, &ff_args->errors,
2085 			FF_LAYOUTRETURN_MAXERR);
2086 
2087 	spin_lock(&args->inode->i_lock);
2088 	ff_args->num_dev = ff_layout_mirror_prepare_stats(&ff_layout->generic_hdr,
2089 			&ff_args->devinfo[0], ARRAY_SIZE(ff_args->devinfo));
2090 	spin_unlock(&args->inode->i_lock);
2091 
2092 	args->ld_private->ops = &layoutreturn_ops;
2093 	args->ld_private->data = ff_args;
2094 	return 0;
2095 out_nomem_free:
2096 	kfree(ff_args);
2097 out_nomem:
2098 	return -ENOMEM;
2099 }
2100 
2101 static int
2102 ff_layout_ntop4(const struct sockaddr *sap, char *buf, const size_t buflen)
2103 {
2104 	const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
2105 
2106 	return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
2107 }
2108 
2109 static size_t
2110 ff_layout_ntop6_noscopeid(const struct sockaddr *sap, char *buf,
2111 			  const int buflen)
2112 {
2113 	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
2114 	const struct in6_addr *addr = &sin6->sin6_addr;
2115 
2116 	/*
2117 	 * RFC 4291, Section 2.2.2
2118 	 *
2119 	 * Shorthanded ANY address
2120 	 */
2121 	if (ipv6_addr_any(addr))
2122 		return snprintf(buf, buflen, "::");
2123 
2124 	/*
2125 	 * RFC 4291, Section 2.2.2
2126 	 *
2127 	 * Shorthanded loopback address
2128 	 */
2129 	if (ipv6_addr_loopback(addr))
2130 		return snprintf(buf, buflen, "::1");
2131 
2132 	/*
2133 	 * RFC 4291, Section 2.2.3
2134 	 *
2135 	 * Special presentation address format for mapped v4
2136 	 * addresses.
2137 	 */
2138 	if (ipv6_addr_v4mapped(addr))
2139 		return snprintf(buf, buflen, "::ffff:%pI4",
2140 					&addr->s6_addr32[3]);
2141 
2142 	/*
2143 	 * RFC 4291, Section 2.2.1
2144 	 */
2145 	return snprintf(buf, buflen, "%pI6c", addr);
2146 }
2147 
2148 /* Derived from rpc_sockaddr2uaddr */
2149 static void
2150 ff_layout_encode_netaddr(struct xdr_stream *xdr, struct nfs4_pnfs_ds_addr *da)
2151 {
2152 	struct sockaddr *sap = (struct sockaddr *)&da->da_addr;
2153 	char portbuf[RPCBIND_MAXUADDRPLEN];
2154 	char addrbuf[RPCBIND_MAXUADDRLEN];
2155 	char *netid;
2156 	unsigned short port;
2157 	int len, netid_len;
2158 	__be32 *p;
2159 
2160 	switch (sap->sa_family) {
2161 	case AF_INET:
2162 		if (ff_layout_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
2163 			return;
2164 		port = ntohs(((struct sockaddr_in *)sap)->sin_port);
2165 		netid = "tcp";
2166 		netid_len = 3;
2167 		break;
2168 	case AF_INET6:
2169 		if (ff_layout_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
2170 			return;
2171 		port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
2172 		netid = "tcp6";
2173 		netid_len = 4;
2174 		break;
2175 	default:
2176 		/* we only support tcp and tcp6 */
2177 		WARN_ON_ONCE(1);
2178 		return;
2179 	}
2180 
2181 	snprintf(portbuf, sizeof(portbuf), ".%u.%u", port >> 8, port & 0xff);
2182 	len = strlcat(addrbuf, portbuf, sizeof(addrbuf));
2183 
2184 	p = xdr_reserve_space(xdr, 4 + netid_len);
2185 	xdr_encode_opaque(p, netid, netid_len);
2186 
2187 	p = xdr_reserve_space(xdr, 4 + len);
2188 	xdr_encode_opaque(p, addrbuf, len);
2189 }
2190 
2191 static void
2192 ff_layout_encode_nfstime(struct xdr_stream *xdr,
2193 			 ktime_t t)
2194 {
2195 	struct timespec64 ts;
2196 	__be32 *p;
2197 
2198 	p = xdr_reserve_space(xdr, 12);
2199 	ts = ktime_to_timespec64(t);
2200 	p = xdr_encode_hyper(p, ts.tv_sec);
2201 	*p++ = cpu_to_be32(ts.tv_nsec);
2202 }
2203 
2204 static void
2205 ff_layout_encode_io_latency(struct xdr_stream *xdr,
2206 			    struct nfs4_ff_io_stat *stat)
2207 {
2208 	__be32 *p;
2209 
2210 	p = xdr_reserve_space(xdr, 5 * 8);
2211 	p = xdr_encode_hyper(p, stat->ops_requested);
2212 	p = xdr_encode_hyper(p, stat->bytes_requested);
2213 	p = xdr_encode_hyper(p, stat->ops_completed);
2214 	p = xdr_encode_hyper(p, stat->bytes_completed);
2215 	p = xdr_encode_hyper(p, stat->bytes_not_delivered);
2216 	ff_layout_encode_nfstime(xdr, stat->total_busy_time);
2217 	ff_layout_encode_nfstime(xdr, stat->aggregate_completion_time);
2218 }
2219 
2220 static void
2221 ff_layout_encode_ff_layoutupdate(struct xdr_stream *xdr,
2222 			      const struct nfs42_layoutstat_devinfo *devinfo,
2223 			      struct nfs4_ff_layout_mirror *mirror)
2224 {
2225 	struct nfs4_pnfs_ds_addr *da;
2226 	struct nfs4_pnfs_ds *ds = mirror->mirror_ds->ds;
2227 	struct nfs_fh *fh = &mirror->fh_versions[0];
2228 	__be32 *p;
2229 
2230 	da = list_first_entry(&ds->ds_addrs, struct nfs4_pnfs_ds_addr, da_node);
2231 	dprintk("%s: DS %s: encoding address %s\n",
2232 		__func__, ds->ds_remotestr, da->da_remotestr);
2233 	/* netaddr4 */
2234 	ff_layout_encode_netaddr(xdr, da);
2235 	/* nfs_fh4 */
2236 	p = xdr_reserve_space(xdr, 4 + fh->size);
2237 	xdr_encode_opaque(p, fh->data, fh->size);
2238 	/* ff_io_latency4 read */
2239 	spin_lock(&mirror->lock);
2240 	ff_layout_encode_io_latency(xdr, &mirror->read_stat.io_stat);
2241 	/* ff_io_latency4 write */
2242 	ff_layout_encode_io_latency(xdr, &mirror->write_stat.io_stat);
2243 	spin_unlock(&mirror->lock);
2244 	/* nfstime4 */
2245 	ff_layout_encode_nfstime(xdr, ktime_sub(ktime_get(), mirror->start_time));
2246 	/* bool */
2247 	p = xdr_reserve_space(xdr, 4);
2248 	*p = cpu_to_be32(false);
2249 }
2250 
2251 static void
2252 ff_layout_encode_layoutstats(struct xdr_stream *xdr, const void *args,
2253 			     const struct nfs4_xdr_opaque_data *opaque)
2254 {
2255 	struct nfs42_layoutstat_devinfo *devinfo = container_of(opaque,
2256 			struct nfs42_layoutstat_devinfo, ld_private);
2257 	__be32 *start;
2258 
2259 	/* layoutupdate length */
2260 	start = xdr_reserve_space(xdr, 4);
2261 	ff_layout_encode_ff_layoutupdate(xdr, devinfo, opaque->data);
2262 
2263 	*start = cpu_to_be32((xdr->p - start - 1) * 4);
2264 }
2265 
2266 static void
2267 ff_layout_free_layoutstats(struct nfs4_xdr_opaque_data *opaque)
2268 {
2269 	struct nfs4_ff_layout_mirror *mirror = opaque->data;
2270 
2271 	ff_layout_put_mirror(mirror);
2272 }
2273 
2274 static const struct nfs4_xdr_opaque_ops layoutstat_ops = {
2275 	.encode = ff_layout_encode_layoutstats,
2276 	.free	= ff_layout_free_layoutstats,
2277 };
2278 
2279 static int
2280 ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
2281 			       struct nfs42_layoutstat_devinfo *devinfo,
2282 			       int dev_limit)
2283 {
2284 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
2285 	struct nfs4_ff_layout_mirror *mirror;
2286 	struct nfs4_deviceid_node *dev;
2287 	int i = 0;
2288 
2289 	list_for_each_entry(mirror, &ff_layout->mirrors, mirrors) {
2290 		if (i >= dev_limit)
2291 			break;
2292 		if (IS_ERR_OR_NULL(mirror->mirror_ds))
2293 			continue;
2294 		if (!test_and_clear_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags))
2295 			continue;
2296 		/* mirror refcount put in cleanup_layoutstats */
2297 		if (!refcount_inc_not_zero(&mirror->ref))
2298 			continue;
2299 		dev = &mirror->mirror_ds->id_node;
2300 		memcpy(&devinfo->dev_id, &dev->deviceid, NFS4_DEVICEID4_SIZE);
2301 		devinfo->offset = 0;
2302 		devinfo->length = NFS4_MAX_UINT64;
2303 		spin_lock(&mirror->lock);
2304 		devinfo->read_count = mirror->read_stat.io_stat.ops_completed;
2305 		devinfo->read_bytes = mirror->read_stat.io_stat.bytes_completed;
2306 		devinfo->write_count = mirror->write_stat.io_stat.ops_completed;
2307 		devinfo->write_bytes = mirror->write_stat.io_stat.bytes_completed;
2308 		spin_unlock(&mirror->lock);
2309 		devinfo->layout_type = LAYOUT_FLEX_FILES;
2310 		devinfo->ld_private.ops = &layoutstat_ops;
2311 		devinfo->ld_private.data = mirror;
2312 
2313 		devinfo++;
2314 		i++;
2315 	}
2316 	return i;
2317 }
2318 
2319 static int
2320 ff_layout_prepare_layoutstats(struct nfs42_layoutstat_args *args)
2321 {
2322 	struct nfs4_flexfile_layout *ff_layout;
2323 	const int dev_count = PNFS_LAYOUTSTATS_MAXDEV;
2324 
2325 	/* For now, send at most PNFS_LAYOUTSTATS_MAXDEV statistics */
2326 	args->devinfo = kmalloc_array(dev_count, sizeof(*args->devinfo), GFP_NOIO);
2327 	if (!args->devinfo)
2328 		return -ENOMEM;
2329 
2330 	spin_lock(&args->inode->i_lock);
2331 	ff_layout = FF_LAYOUT_FROM_HDR(NFS_I(args->inode)->layout);
2332 	args->num_dev = ff_layout_mirror_prepare_stats(&ff_layout->generic_hdr,
2333 			&args->devinfo[0], dev_count);
2334 	spin_unlock(&args->inode->i_lock);
2335 	if (!args->num_dev) {
2336 		kfree(args->devinfo);
2337 		args->devinfo = NULL;
2338 		return -ENOENT;
2339 	}
2340 
2341 	return 0;
2342 }
2343 
2344 static int
2345 ff_layout_set_layoutdriver(struct nfs_server *server,
2346 		const struct nfs_fh *dummy)
2347 {
2348 #if IS_ENABLED(CONFIG_NFS_V4_2)
2349 	server->caps |= NFS_CAP_LAYOUTSTATS;
2350 #endif
2351 	return 0;
2352 }
2353 
2354 static struct pnfs_layoutdriver_type flexfilelayout_type = {
2355 	.id			= LAYOUT_FLEX_FILES,
2356 	.name			= "LAYOUT_FLEX_FILES",
2357 	.owner			= THIS_MODULE,
2358 	.flags			= PNFS_LAYOUTGET_ON_OPEN,
2359 	.max_layoutget_response	= 4096, /* 1 page or so... */
2360 	.set_layoutdriver	= ff_layout_set_layoutdriver,
2361 	.alloc_layout_hdr	= ff_layout_alloc_layout_hdr,
2362 	.free_layout_hdr	= ff_layout_free_layout_hdr,
2363 	.alloc_lseg		= ff_layout_alloc_lseg,
2364 	.free_lseg		= ff_layout_free_lseg,
2365 	.add_lseg		= ff_layout_add_lseg,
2366 	.pg_read_ops		= &ff_layout_pg_read_ops,
2367 	.pg_write_ops		= &ff_layout_pg_write_ops,
2368 	.get_ds_info		= ff_layout_get_ds_info,
2369 	.free_deviceid_node	= ff_layout_free_deviceid_node,
2370 	.mark_request_commit	= pnfs_layout_mark_request_commit,
2371 	.clear_request_commit	= pnfs_generic_clear_request_commit,
2372 	.scan_commit_lists	= pnfs_generic_scan_commit_lists,
2373 	.recover_commit_reqs	= pnfs_generic_recover_commit_reqs,
2374 	.commit_pagelist	= ff_layout_commit_pagelist,
2375 	.read_pagelist		= ff_layout_read_pagelist,
2376 	.write_pagelist		= ff_layout_write_pagelist,
2377 	.alloc_deviceid_node    = ff_layout_alloc_deviceid_node,
2378 	.prepare_layoutreturn   = ff_layout_prepare_layoutreturn,
2379 	.sync			= pnfs_nfs_generic_sync,
2380 	.prepare_layoutstats	= ff_layout_prepare_layoutstats,
2381 };
2382 
2383 static int __init nfs4flexfilelayout_init(void)
2384 {
2385 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Registering...\n",
2386 	       __func__);
2387 	if (!ff_zero_group) {
2388 		ff_zero_group = groups_alloc(0);
2389 		if (!ff_zero_group)
2390 			return -ENOMEM;
2391 	}
2392 	return pnfs_register_layoutdriver(&flexfilelayout_type);
2393 }
2394 
2395 static void __exit nfs4flexfilelayout_exit(void)
2396 {
2397 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Unregistering...\n",
2398 	       __func__);
2399 	pnfs_unregister_layoutdriver(&flexfilelayout_type);
2400 	if (ff_zero_group) {
2401 		put_group_info(ff_zero_group);
2402 		ff_zero_group = NULL;
2403 	}
2404 }
2405 
2406 MODULE_ALIAS("nfs-layouttype4-4");
2407 
2408 MODULE_LICENSE("GPL");
2409 MODULE_DESCRIPTION("The NFSv4 flexfile layout driver");
2410 
2411 module_init(nfs4flexfilelayout_init);
2412 module_exit(nfs4flexfilelayout_exit);
2413