xref: /linux/fs/nfs/flexfilelayout/flexfilelayout.c (revision 32786fdc9506aeba98278c1844d4bfb766863832)
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 	static const ktime_t notime = {0};
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 (ktime_equal(mirror->start_time, notime))
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 retry_strict:
816 	pnfs_put_lseg(pgio->pg_lseg);
817 	pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
818 					   req->wb_context,
819 					   0,
820 					   NFS4_MAX_UINT64,
821 					   IOMODE_READ,
822 					   strict_iomode,
823 					   GFP_KERNEL);
824 	if (IS_ERR(pgio->pg_lseg)) {
825 		pgio->pg_error = PTR_ERR(pgio->pg_lseg);
826 		pgio->pg_lseg = NULL;
827 	}
828 
829 	/* If we don't have checking, do get a IOMODE_RW
830 	 * segment, and the server wants to avoid READs
831 	 * there, then retry!
832 	 */
833 	if (pgio->pg_lseg && !strict_iomode &&
834 	    ff_layout_avoid_read_on_rw(pgio->pg_lseg)) {
835 		strict_iomode = true;
836 		goto retry_strict;
837 	}
838 }
839 
840 static void
841 ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
842 			struct nfs_page *req)
843 {
844 	struct nfs_pgio_mirror *pgm;
845 	struct nfs4_ff_layout_mirror *mirror;
846 	struct nfs4_pnfs_ds *ds;
847 	int ds_idx;
848 
849 retry:
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 	if (!pgio->pg_lseg) {
899 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
900 						   req->wb_context,
901 						   0,
902 						   NFS4_MAX_UINT64,
903 						   IOMODE_RW,
904 						   false,
905 						   GFP_NOFS);
906 		if (IS_ERR(pgio->pg_lseg)) {
907 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
908 			pgio->pg_lseg = NULL;
909 			return;
910 		}
911 	}
912 	/* If no lseg, fall back to write through mds */
913 	if (pgio->pg_lseg == NULL)
914 		goto out_mds;
915 
916 	nfs_init_cinfo(&cinfo, pgio->pg_inode, pgio->pg_dreq);
917 	status = ff_layout_alloc_commit_info(pgio->pg_lseg, &cinfo, GFP_NOFS);
918 	if (status < 0)
919 		goto out_mds;
920 
921 	/* Use a direct mapping of ds_idx to pgio mirror_idx */
922 	if (WARN_ON_ONCE(pgio->pg_mirror_count !=
923 	    FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg)))
924 		goto out_mds;
925 
926 	for (i = 0; i < pgio->pg_mirror_count; i++) {
927 		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, i, true);
928 		if (!ds) {
929 			if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
930 				goto out_mds;
931 			pnfs_put_lseg(pgio->pg_lseg);
932 			pgio->pg_lseg = NULL;
933 			/* Sleep for 1 second before retrying */
934 			ssleep(1);
935 			goto retry;
936 		}
937 		pgm = &pgio->pg_mirrors[i];
938 		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
939 		pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].wsize;
940 	}
941 
942 	return;
943 
944 out_mds:
945 	pnfs_put_lseg(pgio->pg_lseg);
946 	pgio->pg_lseg = NULL;
947 	nfs_pageio_reset_write_mds(pgio);
948 }
949 
950 static unsigned int
951 ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
952 				    struct nfs_page *req)
953 {
954 	if (!pgio->pg_lseg) {
955 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
956 						   req->wb_context,
957 						   0,
958 						   NFS4_MAX_UINT64,
959 						   IOMODE_RW,
960 						   false,
961 						   GFP_NOFS);
962 		if (IS_ERR(pgio->pg_lseg)) {
963 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
964 			pgio->pg_lseg = NULL;
965 			goto out;
966 		}
967 	}
968 	if (pgio->pg_lseg)
969 		return FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg);
970 
971 	/* no lseg means that pnfs is not in use, so no mirroring here */
972 	nfs_pageio_reset_write_mds(pgio);
973 out:
974 	return 1;
975 }
976 
977 static const struct nfs_pageio_ops ff_layout_pg_read_ops = {
978 	.pg_init = ff_layout_pg_init_read,
979 	.pg_test = pnfs_generic_pg_test,
980 	.pg_doio = pnfs_generic_pg_readpages,
981 	.pg_cleanup = pnfs_generic_pg_cleanup,
982 };
983 
984 static const struct nfs_pageio_ops ff_layout_pg_write_ops = {
985 	.pg_init = ff_layout_pg_init_write,
986 	.pg_test = pnfs_generic_pg_test,
987 	.pg_doio = pnfs_generic_pg_writepages,
988 	.pg_get_mirror_count = ff_layout_pg_get_mirror_count_write,
989 	.pg_cleanup = pnfs_generic_pg_cleanup,
990 };
991 
992 static void ff_layout_reset_write(struct nfs_pgio_header *hdr, bool retry_pnfs)
993 {
994 	struct rpc_task *task = &hdr->task;
995 
996 	pnfs_layoutcommit_inode(hdr->inode, false);
997 
998 	if (retry_pnfs) {
999 		dprintk("%s Reset task %5u for i/o through pNFS "
1000 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1001 			hdr->task.tk_pid,
1002 			hdr->inode->i_sb->s_id,
1003 			(unsigned long long)NFS_FILEID(hdr->inode),
1004 			hdr->args.count,
1005 			(unsigned long long)hdr->args.offset);
1006 
1007 		hdr->completion_ops->reschedule_io(hdr);
1008 		return;
1009 	}
1010 
1011 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1012 		dprintk("%s Reset task %5u for i/o through MDS "
1013 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1014 			hdr->task.tk_pid,
1015 			hdr->inode->i_sb->s_id,
1016 			(unsigned long long)NFS_FILEID(hdr->inode),
1017 			hdr->args.count,
1018 			(unsigned long long)hdr->args.offset);
1019 
1020 		task->tk_status = pnfs_write_done_resend_to_mds(hdr);
1021 	}
1022 }
1023 
1024 static void ff_layout_reset_read(struct nfs_pgio_header *hdr)
1025 {
1026 	struct rpc_task *task = &hdr->task;
1027 
1028 	pnfs_layoutcommit_inode(hdr->inode, false);
1029 
1030 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1031 		dprintk("%s Reset task %5u for i/o through MDS "
1032 			"(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
1033 			hdr->task.tk_pid,
1034 			hdr->inode->i_sb->s_id,
1035 			(unsigned long long)NFS_FILEID(hdr->inode),
1036 			hdr->args.count,
1037 			(unsigned long long)hdr->args.offset);
1038 
1039 		task->tk_status = pnfs_read_done_resend_to_mds(hdr);
1040 	}
1041 }
1042 
1043 static int ff_layout_async_handle_error_v4(struct rpc_task *task,
1044 					   struct nfs4_state *state,
1045 					   struct nfs_client *clp,
1046 					   struct pnfs_layout_segment *lseg,
1047 					   int idx)
1048 {
1049 	struct pnfs_layout_hdr *lo = lseg->pls_layout;
1050 	struct inode *inode = lo->plh_inode;
1051 	struct nfs_server *mds_server = NFS_SERVER(inode);
1052 
1053 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1054 	struct nfs_client *mds_client = mds_server->nfs_client;
1055 	struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
1056 
1057 	if (task->tk_status >= 0)
1058 		return 0;
1059 
1060 	switch (task->tk_status) {
1061 	/* MDS state errors */
1062 	case -NFS4ERR_DELEG_REVOKED:
1063 	case -NFS4ERR_ADMIN_REVOKED:
1064 	case -NFS4ERR_BAD_STATEID:
1065 		if (state == NULL)
1066 			break;
1067 		nfs_remove_bad_delegation(state->inode, NULL);
1068 	case -NFS4ERR_OPENMODE:
1069 		if (state == NULL)
1070 			break;
1071 		if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
1072 			goto out_bad_stateid;
1073 		goto wait_on_recovery;
1074 	case -NFS4ERR_EXPIRED:
1075 		if (state != NULL) {
1076 			if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
1077 				goto out_bad_stateid;
1078 		}
1079 		nfs4_schedule_lease_recovery(mds_client);
1080 		goto wait_on_recovery;
1081 	/* DS session errors */
1082 	case -NFS4ERR_BADSESSION:
1083 	case -NFS4ERR_BADSLOT:
1084 	case -NFS4ERR_BAD_HIGH_SLOT:
1085 	case -NFS4ERR_DEADSESSION:
1086 	case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
1087 	case -NFS4ERR_SEQ_FALSE_RETRY:
1088 	case -NFS4ERR_SEQ_MISORDERED:
1089 		dprintk("%s ERROR %d, Reset session. Exchangeid "
1090 			"flags 0x%x\n", __func__, task->tk_status,
1091 			clp->cl_exchange_flags);
1092 		nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
1093 		break;
1094 	case -NFS4ERR_DELAY:
1095 	case -NFS4ERR_GRACE:
1096 		rpc_delay(task, FF_LAYOUT_POLL_RETRY_MAX);
1097 		break;
1098 	case -NFS4ERR_RETRY_UNCACHED_REP:
1099 		break;
1100 	/* Invalidate Layout errors */
1101 	case -NFS4ERR_PNFS_NO_LAYOUT:
1102 	case -ESTALE:           /* mapped NFS4ERR_STALE */
1103 	case -EBADHANDLE:       /* mapped NFS4ERR_BADHANDLE */
1104 	case -EISDIR:           /* mapped NFS4ERR_ISDIR */
1105 	case -NFS4ERR_FHEXPIRED:
1106 	case -NFS4ERR_WRONG_TYPE:
1107 		dprintk("%s Invalid layout error %d\n", __func__,
1108 			task->tk_status);
1109 		/*
1110 		 * Destroy layout so new i/o will get a new layout.
1111 		 * Layout will not be destroyed until all current lseg
1112 		 * references are put. Mark layout as invalid to resend failed
1113 		 * i/o and all i/o waiting on the slot table to the MDS until
1114 		 * layout is destroyed and a new valid layout is obtained.
1115 		 */
1116 		pnfs_destroy_layout(NFS_I(inode));
1117 		rpc_wake_up(&tbl->slot_tbl_waitq);
1118 		goto reset;
1119 	/* RPC connection errors */
1120 	case -ECONNREFUSED:
1121 	case -EHOSTDOWN:
1122 	case -EHOSTUNREACH:
1123 	case -ENETUNREACH:
1124 	case -EIO:
1125 	case -ETIMEDOUT:
1126 	case -EPIPE:
1127 		dprintk("%s DS connection error %d\n", __func__,
1128 			task->tk_status);
1129 		nfs4_mark_deviceid_unavailable(devid);
1130 		rpc_wake_up(&tbl->slot_tbl_waitq);
1131 		/* fall through */
1132 	default:
1133 		if (ff_layout_avoid_mds_available_ds(lseg))
1134 			return -NFS4ERR_RESET_TO_PNFS;
1135 reset:
1136 		dprintk("%s Retry through MDS. Error %d\n", __func__,
1137 			task->tk_status);
1138 		return -NFS4ERR_RESET_TO_MDS;
1139 	}
1140 out:
1141 	task->tk_status = 0;
1142 	return -EAGAIN;
1143 out_bad_stateid:
1144 	task->tk_status = -EIO;
1145 	return 0;
1146 wait_on_recovery:
1147 	rpc_sleep_on(&mds_client->cl_rpcwaitq, task, NULL);
1148 	if (test_bit(NFS4CLNT_MANAGER_RUNNING, &mds_client->cl_state) == 0)
1149 		rpc_wake_up_queued_task(&mds_client->cl_rpcwaitq, task);
1150 	goto out;
1151 }
1152 
1153 /* Retry all errors through either pNFS or MDS except for -EJUKEBOX */
1154 static int ff_layout_async_handle_error_v3(struct rpc_task *task,
1155 					   struct pnfs_layout_segment *lseg,
1156 					   int idx)
1157 {
1158 	struct nfs4_deviceid_node *devid = FF_LAYOUT_DEVID_NODE(lseg, idx);
1159 
1160 	if (task->tk_status >= 0)
1161 		return 0;
1162 
1163 	switch (task->tk_status) {
1164 	/* File access problems. Don't mark the device as unavailable */
1165 	case -EACCES:
1166 	case -ESTALE:
1167 	case -EISDIR:
1168 	case -EBADHANDLE:
1169 	case -ELOOP:
1170 	case -ENOSPC:
1171 		break;
1172 	case -EJUKEBOX:
1173 		nfs_inc_stats(lseg->pls_layout->plh_inode, NFSIOS_DELAY);
1174 		goto out_retry;
1175 	default:
1176 		dprintk("%s DS connection error %d\n", __func__,
1177 			task->tk_status);
1178 		nfs4_mark_deviceid_unavailable(devid);
1179 	}
1180 	/* FIXME: Need to prevent infinite looping here. */
1181 	return -NFS4ERR_RESET_TO_PNFS;
1182 out_retry:
1183 	task->tk_status = 0;
1184 	rpc_restart_call_prepare(task);
1185 	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
1186 	return -EAGAIN;
1187 }
1188 
1189 static int ff_layout_async_handle_error(struct rpc_task *task,
1190 					struct nfs4_state *state,
1191 					struct nfs_client *clp,
1192 					struct pnfs_layout_segment *lseg,
1193 					int idx)
1194 {
1195 	int vers = clp->cl_nfs_mod->rpc_vers->number;
1196 
1197 	switch (vers) {
1198 	case 3:
1199 		return ff_layout_async_handle_error_v3(task, lseg, idx);
1200 	case 4:
1201 		return ff_layout_async_handle_error_v4(task, state, clp,
1202 						       lseg, idx);
1203 	default:
1204 		/* should never happen */
1205 		WARN_ON_ONCE(1);
1206 		return 0;
1207 	}
1208 }
1209 
1210 static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg,
1211 					int idx, u64 offset, u64 length,
1212 					u32 status, int opnum, int error)
1213 {
1214 	struct nfs4_ff_layout_mirror *mirror;
1215 	int err;
1216 
1217 	if (status == 0) {
1218 		switch (error) {
1219 		case -ETIMEDOUT:
1220 		case -EPFNOSUPPORT:
1221 		case -EPROTONOSUPPORT:
1222 		case -EOPNOTSUPP:
1223 		case -ECONNREFUSED:
1224 		case -ECONNRESET:
1225 		case -EHOSTDOWN:
1226 		case -EHOSTUNREACH:
1227 		case -ENETUNREACH:
1228 		case -EADDRINUSE:
1229 		case -ENOBUFS:
1230 		case -EPIPE:
1231 		case -EPERM:
1232 			status = NFS4ERR_NXIO;
1233 			break;
1234 		case -EACCES:
1235 			status = NFS4ERR_ACCESS;
1236 			break;
1237 		default:
1238 			return;
1239 		}
1240 	}
1241 
1242 	switch (status) {
1243 	case NFS4ERR_DELAY:
1244 	case NFS4ERR_GRACE:
1245 		return;
1246 	default:
1247 		break;
1248 	}
1249 
1250 	mirror = FF_LAYOUT_COMP(lseg, idx);
1251 	err = ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),
1252 				       mirror, offset, length, status, opnum,
1253 				       GFP_NOIO);
1254 	pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode, lseg);
1255 	dprintk("%s: err %d op %d status %u\n", __func__, err, opnum, status);
1256 }
1257 
1258 /* NFS_PROTO call done callback routines */
1259 static int ff_layout_read_done_cb(struct rpc_task *task,
1260 				struct nfs_pgio_header *hdr)
1261 {
1262 	int err;
1263 
1264 	trace_nfs4_pnfs_read(hdr, task->tk_status);
1265 	if (task->tk_status < 0)
1266 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1267 					    hdr->args.offset, hdr->args.count,
1268 					    hdr->res.op_status, OP_READ,
1269 					    task->tk_status);
1270 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1271 					   hdr->ds_clp, hdr->lseg,
1272 					   hdr->pgio_mirror_idx);
1273 
1274 	switch (err) {
1275 	case -NFS4ERR_RESET_TO_PNFS:
1276 		if (ff_layout_choose_best_ds_for_read(hdr->lseg,
1277 					hdr->pgio_mirror_idx + 1,
1278 					&hdr->pgio_mirror_idx))
1279 			goto out_eagain;
1280 		ff_layout_read_record_layoutstats_done(task, hdr);
1281 		pnfs_read_resend_pnfs(hdr);
1282 		return task->tk_status;
1283 	case -NFS4ERR_RESET_TO_MDS:
1284 		ff_layout_reset_read(hdr);
1285 		return task->tk_status;
1286 	case -EAGAIN:
1287 		goto out_eagain;
1288 	}
1289 
1290 	return 0;
1291 out_eagain:
1292 	rpc_restart_call_prepare(task);
1293 	return -EAGAIN;
1294 }
1295 
1296 static bool
1297 ff_layout_need_layoutcommit(struct pnfs_layout_segment *lseg)
1298 {
1299 	return !(FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_LAYOUTCOMMIT);
1300 }
1301 
1302 /*
1303  * We reference the rpc_cred of the first WRITE that triggers the need for
1304  * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
1305  * rfc5661 is not clear about which credential should be used.
1306  *
1307  * Flexlayout client should treat DS replied FILE_SYNC as DATA_SYNC, so
1308  * to follow http://www.rfc-editor.org/errata_search.php?rfc=5661&eid=2751
1309  * we always send layoutcommit after DS writes.
1310  */
1311 static void
1312 ff_layout_set_layoutcommit(struct inode *inode,
1313 		struct pnfs_layout_segment *lseg,
1314 		loff_t end_offset)
1315 {
1316 	if (!ff_layout_need_layoutcommit(lseg))
1317 		return;
1318 
1319 	pnfs_set_layoutcommit(inode, lseg, end_offset);
1320 	dprintk("%s inode %lu pls_end_pos %llu\n", __func__, inode->i_ino,
1321 		(unsigned long long) NFS_I(inode)->layout->plh_lwb);
1322 }
1323 
1324 static bool
1325 ff_layout_device_unavailable(struct pnfs_layout_segment *lseg, int idx)
1326 {
1327 	/* No mirroring for now */
1328 	struct nfs4_deviceid_node *node = FF_LAYOUT_DEVID_NODE(lseg, idx);
1329 
1330 	return ff_layout_test_devid_unavailable(node);
1331 }
1332 
1333 static void ff_layout_read_record_layoutstats_start(struct rpc_task *task,
1334 		struct nfs_pgio_header *hdr)
1335 {
1336 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1337 		return;
1338 	nfs4_ff_layout_stat_io_start_read(hdr->inode,
1339 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1340 			hdr->args.count,
1341 			task->tk_start);
1342 }
1343 
1344 static void ff_layout_read_record_layoutstats_done(struct rpc_task *task,
1345 		struct nfs_pgio_header *hdr)
1346 {
1347 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1348 		return;
1349 	nfs4_ff_layout_stat_io_end_read(task,
1350 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1351 			hdr->args.count,
1352 			hdr->res.count);
1353 }
1354 
1355 static int ff_layout_read_prepare_common(struct rpc_task *task,
1356 					 struct nfs_pgio_header *hdr)
1357 {
1358 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1359 		rpc_exit(task, -EIO);
1360 		return -EIO;
1361 	}
1362 	if (ff_layout_device_unavailable(hdr->lseg, hdr->pgio_mirror_idx)) {
1363 		rpc_exit(task, -EHOSTDOWN);
1364 		return -EAGAIN;
1365 	}
1366 
1367 	ff_layout_read_record_layoutstats_start(task, hdr);
1368 	return 0;
1369 }
1370 
1371 /*
1372  * Call ops for the async read/write cases
1373  * In the case of dense layouts, the offset needs to be reset to its
1374  * original value.
1375  */
1376 static void ff_layout_read_prepare_v3(struct rpc_task *task, void *data)
1377 {
1378 	struct nfs_pgio_header *hdr = data;
1379 
1380 	if (ff_layout_read_prepare_common(task, hdr))
1381 		return;
1382 
1383 	rpc_call_start(task);
1384 }
1385 
1386 static int ff_layout_setup_sequence(struct nfs_client *ds_clp,
1387 				    struct nfs4_sequence_args *args,
1388 				    struct nfs4_sequence_res *res,
1389 				    struct rpc_task *task)
1390 {
1391 	if (ds_clp->cl_session)
1392 		return nfs41_setup_sequence(ds_clp->cl_session,
1393 					   args,
1394 					   res,
1395 					   task);
1396 	return nfs40_setup_sequence(ds_clp->cl_slot_tbl,
1397 				   args,
1398 				   res,
1399 				   task);
1400 }
1401 
1402 static void ff_layout_read_prepare_v4(struct rpc_task *task, void *data)
1403 {
1404 	struct nfs_pgio_header *hdr = data;
1405 
1406 	if (ff_layout_setup_sequence(hdr->ds_clp,
1407 				     &hdr->args.seq_args,
1408 				     &hdr->res.seq_res,
1409 				     task))
1410 		return;
1411 
1412 	if (ff_layout_read_prepare_common(task, hdr))
1413 		return;
1414 
1415 	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
1416 			hdr->args.lock_context, FMODE_READ) == -EIO)
1417 		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
1418 }
1419 
1420 static void ff_layout_read_call_done(struct rpc_task *task, void *data)
1421 {
1422 	struct nfs_pgio_header *hdr = data;
1423 
1424 	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
1425 
1426 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1427 	    task->tk_status == 0) {
1428 		nfs4_sequence_done(task, &hdr->res.seq_res);
1429 		return;
1430 	}
1431 
1432 	/* Note this may cause RPC to be resent */
1433 	hdr->mds_ops->rpc_call_done(task, hdr);
1434 }
1435 
1436 static void ff_layout_read_count_stats(struct rpc_task *task, void *data)
1437 {
1438 	struct nfs_pgio_header *hdr = data;
1439 
1440 	ff_layout_read_record_layoutstats_done(task, hdr);
1441 	rpc_count_iostats_metrics(task,
1442 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_READ]);
1443 }
1444 
1445 static void ff_layout_read_release(void *data)
1446 {
1447 	struct nfs_pgio_header *hdr = data;
1448 
1449 	ff_layout_read_record_layoutstats_done(&hdr->task, hdr);
1450 	pnfs_generic_rw_release(data);
1451 }
1452 
1453 
1454 static int ff_layout_write_done_cb(struct rpc_task *task,
1455 				struct nfs_pgio_header *hdr)
1456 {
1457 	loff_t end_offs = 0;
1458 	int err;
1459 
1460 	trace_nfs4_pnfs_write(hdr, task->tk_status);
1461 	if (task->tk_status < 0)
1462 		ff_layout_io_track_ds_error(hdr->lseg, hdr->pgio_mirror_idx,
1463 					    hdr->args.offset, hdr->args.count,
1464 					    hdr->res.op_status, OP_WRITE,
1465 					    task->tk_status);
1466 	err = ff_layout_async_handle_error(task, hdr->args.context->state,
1467 					   hdr->ds_clp, hdr->lseg,
1468 					   hdr->pgio_mirror_idx);
1469 
1470 	switch (err) {
1471 	case -NFS4ERR_RESET_TO_PNFS:
1472 		ff_layout_reset_write(hdr, true);
1473 		return task->tk_status;
1474 	case -NFS4ERR_RESET_TO_MDS:
1475 		ff_layout_reset_write(hdr, false);
1476 		return task->tk_status;
1477 	case -EAGAIN:
1478 		return -EAGAIN;
1479 	}
1480 
1481 	if (hdr->res.verf->committed == NFS_FILE_SYNC ||
1482 	    hdr->res.verf->committed == NFS_DATA_SYNC)
1483 		end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
1484 
1485 	/* Note: if the write is unstable, don't set end_offs until commit */
1486 	ff_layout_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
1487 
1488 	/* zero out fattr since we don't care DS attr at all */
1489 	hdr->fattr.valid = 0;
1490 	if (task->tk_status >= 0)
1491 		nfs_writeback_update_inode(hdr);
1492 
1493 	return 0;
1494 }
1495 
1496 static int ff_layout_commit_done_cb(struct rpc_task *task,
1497 				     struct nfs_commit_data *data)
1498 {
1499 	int err;
1500 
1501 	trace_nfs4_pnfs_commit_ds(data, task->tk_status);
1502 	if (task->tk_status < 0)
1503 		ff_layout_io_track_ds_error(data->lseg, data->ds_commit_index,
1504 					    data->args.offset, data->args.count,
1505 					    data->res.op_status, OP_COMMIT,
1506 					    task->tk_status);
1507 	err = ff_layout_async_handle_error(task, NULL, data->ds_clp,
1508 					   data->lseg, data->ds_commit_index);
1509 
1510 	switch (err) {
1511 	case -NFS4ERR_RESET_TO_PNFS:
1512 		pnfs_generic_prepare_to_resend_writes(data);
1513 		return -EAGAIN;
1514 	case -NFS4ERR_RESET_TO_MDS:
1515 		pnfs_generic_prepare_to_resend_writes(data);
1516 		return -EAGAIN;
1517 	case -EAGAIN:
1518 		rpc_restart_call_prepare(task);
1519 		return -EAGAIN;
1520 	}
1521 
1522 	ff_layout_set_layoutcommit(data->inode, data->lseg, data->lwb);
1523 
1524 	return 0;
1525 }
1526 
1527 static void ff_layout_write_record_layoutstats_start(struct rpc_task *task,
1528 		struct nfs_pgio_header *hdr)
1529 {
1530 	if (test_and_set_bit(NFS_IOHDR_STAT, &hdr->flags))
1531 		return;
1532 	nfs4_ff_layout_stat_io_start_write(hdr->inode,
1533 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1534 			hdr->args.count,
1535 			task->tk_start);
1536 }
1537 
1538 static void ff_layout_write_record_layoutstats_done(struct rpc_task *task,
1539 		struct nfs_pgio_header *hdr)
1540 {
1541 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &hdr->flags))
1542 		return;
1543 	nfs4_ff_layout_stat_io_end_write(task,
1544 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
1545 			hdr->args.count, hdr->res.count,
1546 			hdr->res.verf->committed);
1547 }
1548 
1549 static int ff_layout_write_prepare_common(struct rpc_task *task,
1550 					  struct nfs_pgio_header *hdr)
1551 {
1552 	if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
1553 		rpc_exit(task, -EIO);
1554 		return -EIO;
1555 	}
1556 
1557 	if (ff_layout_device_unavailable(hdr->lseg, hdr->pgio_mirror_idx)) {
1558 		rpc_exit(task, -EHOSTDOWN);
1559 		return -EAGAIN;
1560 	}
1561 
1562 	ff_layout_write_record_layoutstats_start(task, hdr);
1563 	return 0;
1564 }
1565 
1566 static void ff_layout_write_prepare_v3(struct rpc_task *task, void *data)
1567 {
1568 	struct nfs_pgio_header *hdr = data;
1569 
1570 	if (ff_layout_write_prepare_common(task, hdr))
1571 		return;
1572 
1573 	rpc_call_start(task);
1574 }
1575 
1576 static void ff_layout_write_prepare_v4(struct rpc_task *task, void *data)
1577 {
1578 	struct nfs_pgio_header *hdr = data;
1579 
1580 	if (ff_layout_setup_sequence(hdr->ds_clp,
1581 				     &hdr->args.seq_args,
1582 				     &hdr->res.seq_res,
1583 				     task))
1584 		return;
1585 
1586 	if (ff_layout_write_prepare_common(task, hdr))
1587 		return;
1588 
1589 	if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
1590 			hdr->args.lock_context, FMODE_WRITE) == -EIO)
1591 		rpc_exit(task, -EIO); /* lost lock, terminate I/O */
1592 }
1593 
1594 static void ff_layout_write_call_done(struct rpc_task *task, void *data)
1595 {
1596 	struct nfs_pgio_header *hdr = data;
1597 
1598 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
1599 	    task->tk_status == 0) {
1600 		nfs4_sequence_done(task, &hdr->res.seq_res);
1601 		return;
1602 	}
1603 
1604 	/* Note this may cause RPC to be resent */
1605 	hdr->mds_ops->rpc_call_done(task, hdr);
1606 }
1607 
1608 static void ff_layout_write_count_stats(struct rpc_task *task, void *data)
1609 {
1610 	struct nfs_pgio_header *hdr = data;
1611 
1612 	ff_layout_write_record_layoutstats_done(task, hdr);
1613 	rpc_count_iostats_metrics(task,
1614 	    &NFS_CLIENT(hdr->inode)->cl_metrics[NFSPROC4_CLNT_WRITE]);
1615 }
1616 
1617 static void ff_layout_write_release(void *data)
1618 {
1619 	struct nfs_pgio_header *hdr = data;
1620 
1621 	ff_layout_write_record_layoutstats_done(&hdr->task, hdr);
1622 	pnfs_generic_rw_release(data);
1623 }
1624 
1625 static void ff_layout_commit_record_layoutstats_start(struct rpc_task *task,
1626 		struct nfs_commit_data *cdata)
1627 {
1628 	if (test_and_set_bit(NFS_IOHDR_STAT, &cdata->flags))
1629 		return;
1630 	nfs4_ff_layout_stat_io_start_write(cdata->inode,
1631 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1632 			0, task->tk_start);
1633 }
1634 
1635 static void ff_layout_commit_record_layoutstats_done(struct rpc_task *task,
1636 		struct nfs_commit_data *cdata)
1637 {
1638 	struct nfs_page *req;
1639 	__u64 count = 0;
1640 
1641 	if (!test_and_clear_bit(NFS_IOHDR_STAT, &cdata->flags))
1642 		return;
1643 
1644 	if (task->tk_status == 0) {
1645 		list_for_each_entry(req, &cdata->pages, wb_list)
1646 			count += req->wb_bytes;
1647 	}
1648 	nfs4_ff_layout_stat_io_end_write(task,
1649 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
1650 			count, count, NFS_FILE_SYNC);
1651 }
1652 
1653 static void ff_layout_commit_prepare_common(struct rpc_task *task,
1654 		struct nfs_commit_data *cdata)
1655 {
1656 	ff_layout_commit_record_layoutstats_start(task, cdata);
1657 }
1658 
1659 static void ff_layout_commit_prepare_v3(struct rpc_task *task, void *data)
1660 {
1661 	ff_layout_commit_prepare_common(task, data);
1662 	rpc_call_start(task);
1663 }
1664 
1665 static void ff_layout_commit_prepare_v4(struct rpc_task *task, void *data)
1666 {
1667 	struct nfs_commit_data *wdata = data;
1668 
1669 	if (ff_layout_setup_sequence(wdata->ds_clp,
1670 				 &wdata->args.seq_args,
1671 				 &wdata->res.seq_res,
1672 				 task))
1673 		return;
1674 	ff_layout_commit_prepare_common(task, data);
1675 }
1676 
1677 static void ff_layout_commit_done(struct rpc_task *task, void *data)
1678 {
1679 	pnfs_generic_write_commit_done(task, data);
1680 }
1681 
1682 static void ff_layout_commit_count_stats(struct rpc_task *task, void *data)
1683 {
1684 	struct nfs_commit_data *cdata = data;
1685 
1686 	ff_layout_commit_record_layoutstats_done(task, cdata);
1687 	rpc_count_iostats_metrics(task,
1688 	    &NFS_CLIENT(cdata->inode)->cl_metrics[NFSPROC4_CLNT_COMMIT]);
1689 }
1690 
1691 static void ff_layout_commit_release(void *data)
1692 {
1693 	struct nfs_commit_data *cdata = data;
1694 
1695 	ff_layout_commit_record_layoutstats_done(&cdata->task, cdata);
1696 	pnfs_generic_commit_release(data);
1697 }
1698 
1699 static const struct rpc_call_ops ff_layout_read_call_ops_v3 = {
1700 	.rpc_call_prepare = ff_layout_read_prepare_v3,
1701 	.rpc_call_done = ff_layout_read_call_done,
1702 	.rpc_count_stats = ff_layout_read_count_stats,
1703 	.rpc_release = ff_layout_read_release,
1704 };
1705 
1706 static const struct rpc_call_ops ff_layout_read_call_ops_v4 = {
1707 	.rpc_call_prepare = ff_layout_read_prepare_v4,
1708 	.rpc_call_done = ff_layout_read_call_done,
1709 	.rpc_count_stats = ff_layout_read_count_stats,
1710 	.rpc_release = ff_layout_read_release,
1711 };
1712 
1713 static const struct rpc_call_ops ff_layout_write_call_ops_v3 = {
1714 	.rpc_call_prepare = ff_layout_write_prepare_v3,
1715 	.rpc_call_done = ff_layout_write_call_done,
1716 	.rpc_count_stats = ff_layout_write_count_stats,
1717 	.rpc_release = ff_layout_write_release,
1718 };
1719 
1720 static const struct rpc_call_ops ff_layout_write_call_ops_v4 = {
1721 	.rpc_call_prepare = ff_layout_write_prepare_v4,
1722 	.rpc_call_done = ff_layout_write_call_done,
1723 	.rpc_count_stats = ff_layout_write_count_stats,
1724 	.rpc_release = ff_layout_write_release,
1725 };
1726 
1727 static const struct rpc_call_ops ff_layout_commit_call_ops_v3 = {
1728 	.rpc_call_prepare = ff_layout_commit_prepare_v3,
1729 	.rpc_call_done = ff_layout_commit_done,
1730 	.rpc_count_stats = ff_layout_commit_count_stats,
1731 	.rpc_release = ff_layout_commit_release,
1732 };
1733 
1734 static const struct rpc_call_ops ff_layout_commit_call_ops_v4 = {
1735 	.rpc_call_prepare = ff_layout_commit_prepare_v4,
1736 	.rpc_call_done = ff_layout_commit_done,
1737 	.rpc_count_stats = ff_layout_commit_count_stats,
1738 	.rpc_release = ff_layout_commit_release,
1739 };
1740 
1741 static enum pnfs_try_status
1742 ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
1743 {
1744 	struct pnfs_layout_segment *lseg = hdr->lseg;
1745 	struct nfs4_pnfs_ds *ds;
1746 	struct rpc_clnt *ds_clnt;
1747 	struct rpc_cred *ds_cred;
1748 	loff_t offset = hdr->args.offset;
1749 	u32 idx = hdr->pgio_mirror_idx;
1750 	int vers;
1751 	struct nfs_fh *fh;
1752 
1753 	dprintk("--> %s ino %lu pgbase %u req %Zu@%llu\n",
1754 		__func__, hdr->inode->i_ino,
1755 		hdr->args.pgbase, (size_t)hdr->args.count, offset);
1756 
1757 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, false);
1758 	if (!ds)
1759 		goto out_failed;
1760 
1761 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1762 						   hdr->inode);
1763 	if (IS_ERR(ds_clnt))
1764 		goto out_failed;
1765 
1766 	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
1767 	if (!ds_cred)
1768 		goto out_failed;
1769 
1770 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1771 
1772 	dprintk("%s USE DS: %s cl_count %d vers %d\n", __func__,
1773 		ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count), vers);
1774 
1775 	hdr->pgio_done_cb = ff_layout_read_done_cb;
1776 	atomic_inc(&ds->ds_clp->cl_count);
1777 	hdr->ds_clp = ds->ds_clp;
1778 	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
1779 	if (fh)
1780 		hdr->args.fh = fh;
1781 	/*
1782 	 * Note that if we ever decide to split across DSes,
1783 	 * then we may need to handle dense-like offsets.
1784 	 */
1785 	hdr->args.offset = offset;
1786 	hdr->mds_offset = offset;
1787 
1788 	/* Perform an asynchronous read to ds */
1789 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1790 			  vers == 3 ? &ff_layout_read_call_ops_v3 :
1791 				      &ff_layout_read_call_ops_v4,
1792 			  0, RPC_TASK_SOFTCONN);
1793 	put_rpccred(ds_cred);
1794 	return PNFS_ATTEMPTED;
1795 
1796 out_failed:
1797 	if (ff_layout_avoid_mds_available_ds(lseg))
1798 		return PNFS_TRY_AGAIN;
1799 	return PNFS_NOT_ATTEMPTED;
1800 }
1801 
1802 /* Perform async writes. */
1803 static enum pnfs_try_status
1804 ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
1805 {
1806 	struct pnfs_layout_segment *lseg = hdr->lseg;
1807 	struct nfs4_pnfs_ds *ds;
1808 	struct rpc_clnt *ds_clnt;
1809 	struct rpc_cred *ds_cred;
1810 	loff_t offset = hdr->args.offset;
1811 	int vers;
1812 	struct nfs_fh *fh;
1813 	int idx = hdr->pgio_mirror_idx;
1814 
1815 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
1816 	if (!ds)
1817 		return PNFS_NOT_ATTEMPTED;
1818 
1819 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1820 						   hdr->inode);
1821 	if (IS_ERR(ds_clnt))
1822 		return PNFS_NOT_ATTEMPTED;
1823 
1824 	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
1825 	if (!ds_cred)
1826 		return PNFS_NOT_ATTEMPTED;
1827 
1828 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1829 
1830 	dprintk("%s ino %lu sync %d req %Zu@%llu DS: %s cl_count %d vers %d\n",
1831 		__func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
1832 		offset, ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count),
1833 		vers);
1834 
1835 	hdr->pgio_done_cb = ff_layout_write_done_cb;
1836 	atomic_inc(&ds->ds_clp->cl_count);
1837 	hdr->ds_clp = ds->ds_clp;
1838 	hdr->ds_commit_idx = idx;
1839 	fh = nfs4_ff_layout_select_ds_fh(lseg, idx);
1840 	if (fh)
1841 		hdr->args.fh = fh;
1842 
1843 	/*
1844 	 * Note that if we ever decide to split across DSes,
1845 	 * then we may need to handle dense-like offsets.
1846 	 */
1847 	hdr->args.offset = offset;
1848 
1849 	/* Perform an asynchronous write */
1850 	nfs_initiate_pgio(ds_clnt, hdr, ds_cred, ds->ds_clp->rpc_ops,
1851 			  vers == 3 ? &ff_layout_write_call_ops_v3 :
1852 				      &ff_layout_write_call_ops_v4,
1853 			  sync, RPC_TASK_SOFTCONN);
1854 	put_rpccred(ds_cred);
1855 	return PNFS_ATTEMPTED;
1856 }
1857 
1858 static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1859 {
1860 	return i;
1861 }
1862 
1863 static struct nfs_fh *
1864 select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1865 {
1866 	struct nfs4_ff_layout_segment *flseg = FF_LAYOUT_LSEG(lseg);
1867 
1868 	/* FIXME: Assume that there is only one NFS version available
1869 	 * for the DS.
1870 	 */
1871 	return &flseg->mirror_array[i]->fh_versions[0];
1872 }
1873 
1874 static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
1875 {
1876 	struct pnfs_layout_segment *lseg = data->lseg;
1877 	struct nfs4_pnfs_ds *ds;
1878 	struct rpc_clnt *ds_clnt;
1879 	struct rpc_cred *ds_cred;
1880 	u32 idx;
1881 	int vers, ret;
1882 	struct nfs_fh *fh;
1883 
1884 	idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
1885 	ds = nfs4_ff_layout_prepare_ds(lseg, idx, true);
1886 	if (!ds)
1887 		goto out_err;
1888 
1889 	ds_clnt = nfs4_ff_find_or_create_ds_client(lseg, idx, ds->ds_clp,
1890 						   data->inode);
1891 	if (IS_ERR(ds_clnt))
1892 		goto out_err;
1893 
1894 	ds_cred = ff_layout_get_ds_cred(lseg, idx, data->cred);
1895 	if (!ds_cred)
1896 		goto out_err;
1897 
1898 	vers = nfs4_ff_layout_ds_version(lseg, idx);
1899 
1900 	dprintk("%s ino %lu, how %d cl_count %d vers %d\n", __func__,
1901 		data->inode->i_ino, how, atomic_read(&ds->ds_clp->cl_count),
1902 		vers);
1903 	data->commit_done_cb = ff_layout_commit_done_cb;
1904 	data->cred = ds_cred;
1905 	atomic_inc(&ds->ds_clp->cl_count);
1906 	data->ds_clp = ds->ds_clp;
1907 	fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
1908 	if (fh)
1909 		data->args.fh = fh;
1910 
1911 	ret = nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
1912 				   vers == 3 ? &ff_layout_commit_call_ops_v3 :
1913 					       &ff_layout_commit_call_ops_v4,
1914 				   how, RPC_TASK_SOFTCONN);
1915 	put_rpccred(ds_cred);
1916 	return ret;
1917 out_err:
1918 	pnfs_generic_prepare_to_resend_writes(data);
1919 	pnfs_generic_commit_release(data);
1920 	return -EAGAIN;
1921 }
1922 
1923 static int
1924 ff_layout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
1925 			   int how, struct nfs_commit_info *cinfo)
1926 {
1927 	return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
1928 					    ff_layout_initiate_commit);
1929 }
1930 
1931 static struct pnfs_ds_commit_info *
1932 ff_layout_get_ds_info(struct inode *inode)
1933 {
1934 	struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
1935 
1936 	if (layout == NULL)
1937 		return NULL;
1938 
1939 	return &FF_LAYOUT_FROM_HDR(layout)->commit_info;
1940 }
1941 
1942 static void
1943 ff_layout_free_deviceid_node(struct nfs4_deviceid_node *d)
1944 {
1945 	nfs4_ff_layout_free_deviceid(container_of(d, struct nfs4_ff_layout_ds,
1946 						  id_node));
1947 }
1948 
1949 static int ff_layout_encode_ioerr(struct xdr_stream *xdr,
1950 				  const struct nfs4_layoutreturn_args *args,
1951 				  const struct nfs4_flexfile_layoutreturn_args *ff_args)
1952 {
1953 	__be32 *start;
1954 
1955 	start = xdr_reserve_space(xdr, 4);
1956 	if (unlikely(!start))
1957 		return -E2BIG;
1958 
1959 	*start = cpu_to_be32(ff_args->num_errors);
1960 	/* This assume we always return _ALL_ layouts */
1961 	return ff_layout_encode_ds_ioerr(xdr, &ff_args->errors);
1962 }
1963 
1964 static void
1965 encode_opaque_fixed(struct xdr_stream *xdr, const void *buf, size_t len)
1966 {
1967 	__be32 *p;
1968 
1969 	p = xdr_reserve_space(xdr, len);
1970 	xdr_encode_opaque_fixed(p, buf, len);
1971 }
1972 
1973 static void
1974 ff_layout_encode_ff_iostat_head(struct xdr_stream *xdr,
1975 			    const nfs4_stateid *stateid,
1976 			    const struct nfs42_layoutstat_devinfo *devinfo)
1977 {
1978 	__be32 *p;
1979 
1980 	p = xdr_reserve_space(xdr, 8 + 8);
1981 	p = xdr_encode_hyper(p, devinfo->offset);
1982 	p = xdr_encode_hyper(p, devinfo->length);
1983 	encode_opaque_fixed(xdr, stateid->data, NFS4_STATEID_SIZE);
1984 	p = xdr_reserve_space(xdr, 4*8);
1985 	p = xdr_encode_hyper(p, devinfo->read_count);
1986 	p = xdr_encode_hyper(p, devinfo->read_bytes);
1987 	p = xdr_encode_hyper(p, devinfo->write_count);
1988 	p = xdr_encode_hyper(p, devinfo->write_bytes);
1989 	encode_opaque_fixed(xdr, devinfo->dev_id.data, NFS4_DEVICEID4_SIZE);
1990 }
1991 
1992 static void
1993 ff_layout_encode_ff_iostat(struct xdr_stream *xdr,
1994 			    const nfs4_stateid *stateid,
1995 			    const struct nfs42_layoutstat_devinfo *devinfo)
1996 {
1997 	ff_layout_encode_ff_iostat_head(xdr, stateid, devinfo);
1998 	ff_layout_encode_ff_layoutupdate(xdr, devinfo,
1999 			devinfo->ld_private.data);
2000 }
2001 
2002 /* report nothing for now */
2003 static void ff_layout_encode_iostats_array(struct xdr_stream *xdr,
2004 		const struct nfs4_layoutreturn_args *args,
2005 		struct nfs4_flexfile_layoutreturn_args *ff_args)
2006 {
2007 	__be32 *p;
2008 	int i;
2009 
2010 	p = xdr_reserve_space(xdr, 4);
2011 	*p = cpu_to_be32(ff_args->num_dev);
2012 	for (i = 0; i < ff_args->num_dev; i++)
2013 		ff_layout_encode_ff_iostat(xdr,
2014 				&args->layout->plh_stateid,
2015 				&ff_args->devinfo[i]);
2016 }
2017 
2018 static void
2019 ff_layout_free_iostats_array(struct nfs42_layoutstat_devinfo *devinfo,
2020 		unsigned int num_entries)
2021 {
2022 	unsigned int i;
2023 
2024 	for (i = 0; i < num_entries; i++) {
2025 		if (!devinfo[i].ld_private.ops)
2026 			continue;
2027 		if (!devinfo[i].ld_private.ops->free)
2028 			continue;
2029 		devinfo[i].ld_private.ops->free(&devinfo[i].ld_private);
2030 	}
2031 }
2032 
2033 static struct nfs4_deviceid_node *
2034 ff_layout_alloc_deviceid_node(struct nfs_server *server,
2035 			      struct pnfs_device *pdev, gfp_t gfp_flags)
2036 {
2037 	struct nfs4_ff_layout_ds *dsaddr;
2038 
2039 	dsaddr = nfs4_ff_alloc_deviceid_node(server, pdev, gfp_flags);
2040 	if (!dsaddr)
2041 		return NULL;
2042 	return &dsaddr->id_node;
2043 }
2044 
2045 static void
2046 ff_layout_encode_layoutreturn(struct xdr_stream *xdr,
2047 		const void *voidargs,
2048 		const struct nfs4_xdr_opaque_data *ff_opaque)
2049 {
2050 	const struct nfs4_layoutreturn_args *args = voidargs;
2051 	struct nfs4_flexfile_layoutreturn_args *ff_args = ff_opaque->data;
2052 	struct xdr_buf tmp_buf = {
2053 		.head = {
2054 			[0] = {
2055 				.iov_base = page_address(ff_args->pages[0]),
2056 			},
2057 		},
2058 		.buflen = PAGE_SIZE,
2059 	};
2060 	struct xdr_stream tmp_xdr;
2061 	__be32 *start;
2062 
2063 	dprintk("%s: Begin\n", __func__);
2064 
2065 	xdr_init_encode(&tmp_xdr, &tmp_buf, NULL);
2066 
2067 	ff_layout_encode_ioerr(&tmp_xdr, args, ff_args);
2068 	ff_layout_encode_iostats_array(&tmp_xdr, args, ff_args);
2069 
2070 	start = xdr_reserve_space(xdr, 4);
2071 	*start = cpu_to_be32(tmp_buf.len);
2072 	xdr_write_pages(xdr, ff_args->pages, 0, tmp_buf.len);
2073 
2074 	dprintk("%s: Return\n", __func__);
2075 }
2076 
2077 static void
2078 ff_layout_free_layoutreturn(struct nfs4_xdr_opaque_data *args)
2079 {
2080 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2081 
2082 	if (!args->data)
2083 		return;
2084 	ff_args = args->data;
2085 	args->data = NULL;
2086 
2087 	ff_layout_free_ds_ioerr(&ff_args->errors);
2088 	ff_layout_free_iostats_array(ff_args->devinfo, ff_args->num_dev);
2089 
2090 	put_page(ff_args->pages[0]);
2091 	kfree(ff_args);
2092 }
2093 
2094 const struct nfs4_xdr_opaque_ops layoutreturn_ops = {
2095 	.encode = ff_layout_encode_layoutreturn,
2096 	.free = ff_layout_free_layoutreturn,
2097 };
2098 
2099 static int
2100 ff_layout_prepare_layoutreturn(struct nfs4_layoutreturn_args *args)
2101 {
2102 	struct nfs4_flexfile_layoutreturn_args *ff_args;
2103 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(args->layout);
2104 
2105 	ff_args = kmalloc(sizeof(*ff_args), GFP_KERNEL);
2106 	if (!ff_args)
2107 		goto out_nomem;
2108 	ff_args->pages[0] = alloc_page(GFP_KERNEL);
2109 	if (!ff_args->pages[0])
2110 		goto out_nomem_free;
2111 
2112 	INIT_LIST_HEAD(&ff_args->errors);
2113 	ff_args->num_errors = ff_layout_fetch_ds_ioerr(args->layout,
2114 			&args->range, &ff_args->errors,
2115 			FF_LAYOUTRETURN_MAXERR);
2116 
2117 	spin_lock(&args->inode->i_lock);
2118 	ff_args->num_dev = ff_layout_mirror_prepare_stats(&ff_layout->generic_hdr,
2119 			&ff_args->devinfo[0], ARRAY_SIZE(ff_args->devinfo));
2120 	spin_unlock(&args->inode->i_lock);
2121 
2122 	args->ld_private->ops = &layoutreturn_ops;
2123 	args->ld_private->data = ff_args;
2124 	return 0;
2125 out_nomem_free:
2126 	kfree(ff_args);
2127 out_nomem:
2128 	return -ENOMEM;
2129 }
2130 
2131 static int
2132 ff_layout_ntop4(const struct sockaddr *sap, char *buf, const size_t buflen)
2133 {
2134 	const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
2135 
2136 	return snprintf(buf, buflen, "%pI4", &sin->sin_addr);
2137 }
2138 
2139 static size_t
2140 ff_layout_ntop6_noscopeid(const struct sockaddr *sap, char *buf,
2141 			  const int buflen)
2142 {
2143 	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
2144 	const struct in6_addr *addr = &sin6->sin6_addr;
2145 
2146 	/*
2147 	 * RFC 4291, Section 2.2.2
2148 	 *
2149 	 * Shorthanded ANY address
2150 	 */
2151 	if (ipv6_addr_any(addr))
2152 		return snprintf(buf, buflen, "::");
2153 
2154 	/*
2155 	 * RFC 4291, Section 2.2.2
2156 	 *
2157 	 * Shorthanded loopback address
2158 	 */
2159 	if (ipv6_addr_loopback(addr))
2160 		return snprintf(buf, buflen, "::1");
2161 
2162 	/*
2163 	 * RFC 4291, Section 2.2.3
2164 	 *
2165 	 * Special presentation address format for mapped v4
2166 	 * addresses.
2167 	 */
2168 	if (ipv6_addr_v4mapped(addr))
2169 		return snprintf(buf, buflen, "::ffff:%pI4",
2170 					&addr->s6_addr32[3]);
2171 
2172 	/*
2173 	 * RFC 4291, Section 2.2.1
2174 	 */
2175 	return snprintf(buf, buflen, "%pI6c", addr);
2176 }
2177 
2178 /* Derived from rpc_sockaddr2uaddr */
2179 static void
2180 ff_layout_encode_netaddr(struct xdr_stream *xdr, struct nfs4_pnfs_ds_addr *da)
2181 {
2182 	struct sockaddr *sap = (struct sockaddr *)&da->da_addr;
2183 	char portbuf[RPCBIND_MAXUADDRPLEN];
2184 	char addrbuf[RPCBIND_MAXUADDRLEN];
2185 	char *netid;
2186 	unsigned short port;
2187 	int len, netid_len;
2188 	__be32 *p;
2189 
2190 	switch (sap->sa_family) {
2191 	case AF_INET:
2192 		if (ff_layout_ntop4(sap, addrbuf, sizeof(addrbuf)) == 0)
2193 			return;
2194 		port = ntohs(((struct sockaddr_in *)sap)->sin_port);
2195 		netid = "tcp";
2196 		netid_len = 3;
2197 		break;
2198 	case AF_INET6:
2199 		if (ff_layout_ntop6_noscopeid(sap, addrbuf, sizeof(addrbuf)) == 0)
2200 			return;
2201 		port = ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
2202 		netid = "tcp6";
2203 		netid_len = 4;
2204 		break;
2205 	default:
2206 		/* we only support tcp and tcp6 */
2207 		WARN_ON_ONCE(1);
2208 		return;
2209 	}
2210 
2211 	snprintf(portbuf, sizeof(portbuf), ".%u.%u", port >> 8, port & 0xff);
2212 	len = strlcat(addrbuf, portbuf, sizeof(addrbuf));
2213 
2214 	p = xdr_reserve_space(xdr, 4 + netid_len);
2215 	xdr_encode_opaque(p, netid, netid_len);
2216 
2217 	p = xdr_reserve_space(xdr, 4 + len);
2218 	xdr_encode_opaque(p, addrbuf, len);
2219 }
2220 
2221 static void
2222 ff_layout_encode_nfstime(struct xdr_stream *xdr,
2223 			 ktime_t t)
2224 {
2225 	struct timespec64 ts;
2226 	__be32 *p;
2227 
2228 	p = xdr_reserve_space(xdr, 12);
2229 	ts = ktime_to_timespec64(t);
2230 	p = xdr_encode_hyper(p, ts.tv_sec);
2231 	*p++ = cpu_to_be32(ts.tv_nsec);
2232 }
2233 
2234 static void
2235 ff_layout_encode_io_latency(struct xdr_stream *xdr,
2236 			    struct nfs4_ff_io_stat *stat)
2237 {
2238 	__be32 *p;
2239 
2240 	p = xdr_reserve_space(xdr, 5 * 8);
2241 	p = xdr_encode_hyper(p, stat->ops_requested);
2242 	p = xdr_encode_hyper(p, stat->bytes_requested);
2243 	p = xdr_encode_hyper(p, stat->ops_completed);
2244 	p = xdr_encode_hyper(p, stat->bytes_completed);
2245 	p = xdr_encode_hyper(p, stat->bytes_not_delivered);
2246 	ff_layout_encode_nfstime(xdr, stat->total_busy_time);
2247 	ff_layout_encode_nfstime(xdr, stat->aggregate_completion_time);
2248 }
2249 
2250 static void
2251 ff_layout_encode_ff_layoutupdate(struct xdr_stream *xdr,
2252 			      const struct nfs42_layoutstat_devinfo *devinfo,
2253 			      struct nfs4_ff_layout_mirror *mirror)
2254 {
2255 	struct nfs4_pnfs_ds_addr *da;
2256 	struct nfs4_pnfs_ds *ds = mirror->mirror_ds->ds;
2257 	struct nfs_fh *fh = &mirror->fh_versions[0];
2258 	__be32 *p;
2259 
2260 	da = list_first_entry(&ds->ds_addrs, struct nfs4_pnfs_ds_addr, da_node);
2261 	dprintk("%s: DS %s: encoding address %s\n",
2262 		__func__, ds->ds_remotestr, da->da_remotestr);
2263 	/* netaddr4 */
2264 	ff_layout_encode_netaddr(xdr, da);
2265 	/* nfs_fh4 */
2266 	p = xdr_reserve_space(xdr, 4 + fh->size);
2267 	xdr_encode_opaque(p, fh->data, fh->size);
2268 	/* ff_io_latency4 read */
2269 	spin_lock(&mirror->lock);
2270 	ff_layout_encode_io_latency(xdr, &mirror->read_stat.io_stat);
2271 	/* ff_io_latency4 write */
2272 	ff_layout_encode_io_latency(xdr, &mirror->write_stat.io_stat);
2273 	spin_unlock(&mirror->lock);
2274 	/* nfstime4 */
2275 	ff_layout_encode_nfstime(xdr, ktime_sub(ktime_get(), mirror->start_time));
2276 	/* bool */
2277 	p = xdr_reserve_space(xdr, 4);
2278 	*p = cpu_to_be32(false);
2279 }
2280 
2281 static void
2282 ff_layout_encode_layoutstats(struct xdr_stream *xdr, const void *args,
2283 			     const struct nfs4_xdr_opaque_data *opaque)
2284 {
2285 	struct nfs42_layoutstat_devinfo *devinfo = container_of(opaque,
2286 			struct nfs42_layoutstat_devinfo, ld_private);
2287 	__be32 *start;
2288 
2289 	/* layoutupdate length */
2290 	start = xdr_reserve_space(xdr, 4);
2291 	ff_layout_encode_ff_layoutupdate(xdr, devinfo, opaque->data);
2292 
2293 	*start = cpu_to_be32((xdr->p - start - 1) * 4);
2294 }
2295 
2296 static void
2297 ff_layout_free_layoutstats(struct nfs4_xdr_opaque_data *opaque)
2298 {
2299 	struct nfs4_ff_layout_mirror *mirror = opaque->data;
2300 
2301 	ff_layout_put_mirror(mirror);
2302 }
2303 
2304 static const struct nfs4_xdr_opaque_ops layoutstat_ops = {
2305 	.encode = ff_layout_encode_layoutstats,
2306 	.free	= ff_layout_free_layoutstats,
2307 };
2308 
2309 static int
2310 ff_layout_mirror_prepare_stats(struct pnfs_layout_hdr *lo,
2311 			       struct nfs42_layoutstat_devinfo *devinfo,
2312 			       int dev_limit)
2313 {
2314 	struct nfs4_flexfile_layout *ff_layout = FF_LAYOUT_FROM_HDR(lo);
2315 	struct nfs4_ff_layout_mirror *mirror;
2316 	struct nfs4_deviceid_node *dev;
2317 	int i = 0;
2318 
2319 	list_for_each_entry(mirror, &ff_layout->mirrors, mirrors) {
2320 		if (i >= dev_limit)
2321 			break;
2322 		if (IS_ERR_OR_NULL(mirror->mirror_ds))
2323 			continue;
2324 		if (!test_and_clear_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags))
2325 			continue;
2326 		/* mirror refcount put in cleanup_layoutstats */
2327 		if (!atomic_inc_not_zero(&mirror->ref))
2328 			continue;
2329 		dev = &mirror->mirror_ds->id_node;
2330 		memcpy(&devinfo->dev_id, &dev->deviceid, NFS4_DEVICEID4_SIZE);
2331 		devinfo->offset = 0;
2332 		devinfo->length = NFS4_MAX_UINT64;
2333 		spin_lock(&mirror->lock);
2334 		devinfo->read_count = mirror->read_stat.io_stat.ops_completed;
2335 		devinfo->read_bytes = mirror->read_stat.io_stat.bytes_completed;
2336 		devinfo->write_count = mirror->write_stat.io_stat.ops_completed;
2337 		devinfo->write_bytes = mirror->write_stat.io_stat.bytes_completed;
2338 		spin_unlock(&mirror->lock);
2339 		devinfo->layout_type = LAYOUT_FLEX_FILES;
2340 		devinfo->ld_private.ops = &layoutstat_ops;
2341 		devinfo->ld_private.data = mirror;
2342 
2343 		devinfo++;
2344 		i++;
2345 	}
2346 	return i;
2347 }
2348 
2349 static int
2350 ff_layout_prepare_layoutstats(struct nfs42_layoutstat_args *args)
2351 {
2352 	struct nfs4_flexfile_layout *ff_layout;
2353 	const int dev_count = PNFS_LAYOUTSTATS_MAXDEV;
2354 
2355 	/* For now, send at most PNFS_LAYOUTSTATS_MAXDEV statistics */
2356 	args->devinfo = kmalloc_array(dev_count, sizeof(*args->devinfo), GFP_NOIO);
2357 	if (!args->devinfo)
2358 		return -ENOMEM;
2359 
2360 	spin_lock(&args->inode->i_lock);
2361 	ff_layout = FF_LAYOUT_FROM_HDR(NFS_I(args->inode)->layout);
2362 	args->num_dev = ff_layout_mirror_prepare_stats(&ff_layout->generic_hdr,
2363 			&args->devinfo[0], dev_count);
2364 	spin_unlock(&args->inode->i_lock);
2365 	if (!args->num_dev) {
2366 		kfree(args->devinfo);
2367 		args->devinfo = NULL;
2368 		return -ENOENT;
2369 	}
2370 
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 	.alloc_layout_hdr	= ff_layout_alloc_layout_hdr,
2379 	.free_layout_hdr	= ff_layout_free_layout_hdr,
2380 	.alloc_lseg		= ff_layout_alloc_lseg,
2381 	.free_lseg		= ff_layout_free_lseg,
2382 	.add_lseg		= ff_layout_add_lseg,
2383 	.pg_read_ops		= &ff_layout_pg_read_ops,
2384 	.pg_write_ops		= &ff_layout_pg_write_ops,
2385 	.get_ds_info		= ff_layout_get_ds_info,
2386 	.free_deviceid_node	= ff_layout_free_deviceid_node,
2387 	.mark_request_commit	= pnfs_layout_mark_request_commit,
2388 	.clear_request_commit	= pnfs_generic_clear_request_commit,
2389 	.scan_commit_lists	= pnfs_generic_scan_commit_lists,
2390 	.recover_commit_reqs	= pnfs_generic_recover_commit_reqs,
2391 	.commit_pagelist	= ff_layout_commit_pagelist,
2392 	.read_pagelist		= ff_layout_read_pagelist,
2393 	.write_pagelist		= ff_layout_write_pagelist,
2394 	.alloc_deviceid_node    = ff_layout_alloc_deviceid_node,
2395 	.prepare_layoutreturn   = ff_layout_prepare_layoutreturn,
2396 	.sync			= pnfs_nfs_generic_sync,
2397 	.prepare_layoutstats	= ff_layout_prepare_layoutstats,
2398 };
2399 
2400 static int __init nfs4flexfilelayout_init(void)
2401 {
2402 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Registering...\n",
2403 	       __func__);
2404 	if (!ff_zero_group) {
2405 		ff_zero_group = groups_alloc(0);
2406 		if (!ff_zero_group)
2407 			return -ENOMEM;
2408 	}
2409 	return pnfs_register_layoutdriver(&flexfilelayout_type);
2410 }
2411 
2412 static void __exit nfs4flexfilelayout_exit(void)
2413 {
2414 	printk(KERN_INFO "%s: NFSv4 Flexfile Layout Driver Unregistering...\n",
2415 	       __func__);
2416 	pnfs_unregister_layoutdriver(&flexfilelayout_type);
2417 	if (ff_zero_group) {
2418 		put_group_info(ff_zero_group);
2419 		ff_zero_group = NULL;
2420 	}
2421 }
2422 
2423 MODULE_ALIAS("nfs-layouttype4-4");
2424 
2425 MODULE_LICENSE("GPL");
2426 MODULE_DESCRIPTION("The NFSv4 flexfile layout driver");
2427 
2428 module_init(nfs4flexfilelayout_init);
2429 module_exit(nfs4flexfilelayout_exit);
2430