xref: /openbmc/linux/fs/nfs/pnfs.c (revision a67ff6a54095e27093ea501fb143fefe51a536c2)
1 /*
2  *  pNFS functions to call and manage layout drivers.
3  *
4  *  Copyright (c) 2002 [year of first publication]
5  *  The Regents of the University of Michigan
6  *  All Rights Reserved
7  *
8  *  Dean Hildebrand <dhildebz@umich.edu>
9  *
10  *  Permission is granted to use, copy, create derivative works, and
11  *  redistribute this software and such derivative works for any purpose,
12  *  so long as the name of the University of Michigan is not used in
13  *  any advertising or publicity pertaining to the use or distribution
14  *  of this software without specific, written prior authorization. If
15  *  the above copyright notice or any other identification of the
16  *  University of Michigan is included in any copy of any portion of
17  *  this software, then the disclaimer below must also be included.
18  *
19  *  This software is provided as is, without representation or warranty
20  *  of any kind either express or implied, including without limitation
21  *  the implied warranties of merchantability, fitness for a particular
22  *  purpose, or noninfringement.  The Regents of the University of
23  *  Michigan shall not be liable for any damages, including special,
24  *  indirect, incidental, or consequential damages, with respect to any
25  *  claim arising out of or in connection with the use of the software,
26  *  even if it has been or is hereafter advised of the possibility of
27  *  such damages.
28  */
29 
30 #include <linux/nfs_fs.h>
31 #include <linux/nfs_page.h>
32 #include <linux/module.h>
33 #include "internal.h"
34 #include "pnfs.h"
35 #include "iostat.h"
36 
37 #define NFSDBG_FACILITY		NFSDBG_PNFS
38 
39 /* Locking:
40  *
41  * pnfs_spinlock:
42  *      protects pnfs_modules_tbl.
43  */
44 static DEFINE_SPINLOCK(pnfs_spinlock);
45 
46 /*
47  * pnfs_modules_tbl holds all pnfs modules
48  */
49 static LIST_HEAD(pnfs_modules_tbl);
50 
51 /* Return the registered pnfs layout driver module matching given id */
52 static struct pnfs_layoutdriver_type *
53 find_pnfs_driver_locked(u32 id)
54 {
55 	struct pnfs_layoutdriver_type *local;
56 
57 	list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid)
58 		if (local->id == id)
59 			goto out;
60 	local = NULL;
61 out:
62 	dprintk("%s: Searching for id %u, found %p\n", __func__, id, local);
63 	return local;
64 }
65 
66 static struct pnfs_layoutdriver_type *
67 find_pnfs_driver(u32 id)
68 {
69 	struct pnfs_layoutdriver_type *local;
70 
71 	spin_lock(&pnfs_spinlock);
72 	local = find_pnfs_driver_locked(id);
73 	spin_unlock(&pnfs_spinlock);
74 	return local;
75 }
76 
77 void
78 unset_pnfs_layoutdriver(struct nfs_server *nfss)
79 {
80 	if (nfss->pnfs_curr_ld) {
81 		if (nfss->pnfs_curr_ld->clear_layoutdriver)
82 			nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
83 		module_put(nfss->pnfs_curr_ld->owner);
84 	}
85 	nfss->pnfs_curr_ld = NULL;
86 }
87 
88 /*
89  * Try to set the server's pnfs module to the pnfs layout type specified by id.
90  * Currently only one pNFS layout driver per filesystem is supported.
91  *
92  * @id layout type. Zero (illegal layout type) indicates pNFS not in use.
93  */
94 void
95 set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
96 		      u32 id)
97 {
98 	struct pnfs_layoutdriver_type *ld_type = NULL;
99 
100 	if (id == 0)
101 		goto out_no_driver;
102 	if (!(server->nfs_client->cl_exchange_flags &
103 		 (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) {
104 		printk(KERN_ERR "%s: id %u cl_exchange_flags 0x%x\n", __func__,
105 		       id, server->nfs_client->cl_exchange_flags);
106 		goto out_no_driver;
107 	}
108 	ld_type = find_pnfs_driver(id);
109 	if (!ld_type) {
110 		request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX, id);
111 		ld_type = find_pnfs_driver(id);
112 		if (!ld_type) {
113 			dprintk("%s: No pNFS module found for %u.\n",
114 				__func__, id);
115 			goto out_no_driver;
116 		}
117 	}
118 	if (!try_module_get(ld_type->owner)) {
119 		dprintk("%s: Could not grab reference on module\n", __func__);
120 		goto out_no_driver;
121 	}
122 	server->pnfs_curr_ld = ld_type;
123 	if (ld_type->set_layoutdriver
124 	    && ld_type->set_layoutdriver(server, mntfh)) {
125 		printk(KERN_ERR "%s: Error initializing pNFS layout driver %u.\n",
126 				__func__, id);
127 		module_put(ld_type->owner);
128 		goto out_no_driver;
129 	}
130 
131 	dprintk("%s: pNFS module for %u set\n", __func__, id);
132 	return;
133 
134 out_no_driver:
135 	dprintk("%s: Using NFSv4 I/O\n", __func__);
136 	server->pnfs_curr_ld = NULL;
137 }
138 
139 int
140 pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
141 {
142 	int status = -EINVAL;
143 	struct pnfs_layoutdriver_type *tmp;
144 
145 	if (ld_type->id == 0) {
146 		printk(KERN_ERR "%s id 0 is reserved\n", __func__);
147 		return status;
148 	}
149 	if (!ld_type->alloc_lseg || !ld_type->free_lseg) {
150 		printk(KERN_ERR "%s Layout driver must provide "
151 		       "alloc_lseg and free_lseg.\n", __func__);
152 		return status;
153 	}
154 
155 	spin_lock(&pnfs_spinlock);
156 	tmp = find_pnfs_driver_locked(ld_type->id);
157 	if (!tmp) {
158 		list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl);
159 		status = 0;
160 		dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id,
161 			ld_type->name);
162 	} else {
163 		printk(KERN_ERR "%s Module with id %d already loaded!\n",
164 			__func__, ld_type->id);
165 	}
166 	spin_unlock(&pnfs_spinlock);
167 
168 	return status;
169 }
170 EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver);
171 
172 void
173 pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
174 {
175 	dprintk("%s Deregistering id:%u\n", __func__, ld_type->id);
176 	spin_lock(&pnfs_spinlock);
177 	list_del(&ld_type->pnfs_tblid);
178 	spin_unlock(&pnfs_spinlock);
179 }
180 EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);
181 
182 /*
183  * pNFS client layout cache
184  */
185 
186 /* Need to hold i_lock if caller does not already hold reference */
187 void
188 get_layout_hdr(struct pnfs_layout_hdr *lo)
189 {
190 	atomic_inc(&lo->plh_refcount);
191 }
192 
193 static struct pnfs_layout_hdr *
194 pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
195 {
196 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
197 	return ld->alloc_layout_hdr ? ld->alloc_layout_hdr(ino, gfp_flags) :
198 		kzalloc(sizeof(struct pnfs_layout_hdr), gfp_flags);
199 }
200 
201 static void
202 pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
203 {
204 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(lo->plh_inode)->pnfs_curr_ld;
205 	put_rpccred(lo->plh_lc_cred);
206 	return ld->alloc_layout_hdr ? ld->free_layout_hdr(lo) : kfree(lo);
207 }
208 
209 static void
210 destroy_layout_hdr(struct pnfs_layout_hdr *lo)
211 {
212 	dprintk("%s: freeing layout cache %p\n", __func__, lo);
213 	BUG_ON(!list_empty(&lo->plh_layouts));
214 	NFS_I(lo->plh_inode)->layout = NULL;
215 	pnfs_free_layout_hdr(lo);
216 }
217 
218 static void
219 put_layout_hdr_locked(struct pnfs_layout_hdr *lo)
220 {
221 	if (atomic_dec_and_test(&lo->plh_refcount))
222 		destroy_layout_hdr(lo);
223 }
224 
225 void
226 put_layout_hdr(struct pnfs_layout_hdr *lo)
227 {
228 	struct inode *inode = lo->plh_inode;
229 
230 	if (atomic_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
231 		destroy_layout_hdr(lo);
232 		spin_unlock(&inode->i_lock);
233 	}
234 }
235 
236 static void
237 init_lseg(struct pnfs_layout_hdr *lo, struct pnfs_layout_segment *lseg)
238 {
239 	INIT_LIST_HEAD(&lseg->pls_list);
240 	INIT_LIST_HEAD(&lseg->pls_lc_list);
241 	atomic_set(&lseg->pls_refcount, 1);
242 	smp_mb();
243 	set_bit(NFS_LSEG_VALID, &lseg->pls_flags);
244 	lseg->pls_layout = lo;
245 }
246 
247 static void free_lseg(struct pnfs_layout_segment *lseg)
248 {
249 	struct inode *ino = lseg->pls_layout->plh_inode;
250 
251 	NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
252 	/* Matched by get_layout_hdr in pnfs_insert_layout */
253 	put_layout_hdr(NFS_I(ino)->layout);
254 }
255 
256 static void
257 put_lseg_common(struct pnfs_layout_segment *lseg)
258 {
259 	struct inode *inode = lseg->pls_layout->plh_inode;
260 
261 	WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
262 	list_del_init(&lseg->pls_list);
263 	if (list_empty(&lseg->pls_layout->plh_segs)) {
264 		set_bit(NFS_LAYOUT_DESTROYED, &lseg->pls_layout->plh_flags);
265 		/* Matched by initial refcount set in alloc_init_layout_hdr */
266 		put_layout_hdr_locked(lseg->pls_layout);
267 	}
268 	rpc_wake_up(&NFS_SERVER(inode)->roc_rpcwaitq);
269 }
270 
271 void
272 put_lseg(struct pnfs_layout_segment *lseg)
273 {
274 	struct inode *inode;
275 
276 	if (!lseg)
277 		return;
278 
279 	dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
280 		atomic_read(&lseg->pls_refcount),
281 		test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
282 	inode = lseg->pls_layout->plh_inode;
283 	if (atomic_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
284 		LIST_HEAD(free_me);
285 
286 		put_lseg_common(lseg);
287 		list_add(&lseg->pls_list, &free_me);
288 		spin_unlock(&inode->i_lock);
289 		pnfs_free_lseg_list(&free_me);
290 	}
291 }
292 EXPORT_SYMBOL_GPL(put_lseg);
293 
294 static inline u64
295 end_offset(u64 start, u64 len)
296 {
297 	u64 end;
298 
299 	end = start + len;
300 	return end >= start ? end : NFS4_MAX_UINT64;
301 }
302 
303 /* last octet in a range */
304 static inline u64
305 last_byte_offset(u64 start, u64 len)
306 {
307 	u64 end;
308 
309 	BUG_ON(!len);
310 	end = start + len;
311 	return end > start ? end - 1 : NFS4_MAX_UINT64;
312 }
313 
314 /*
315  * is l2 fully contained in l1?
316  *   start1                             end1
317  *   [----------------------------------)
318  *           start2           end2
319  *           [----------------)
320  */
321 static inline int
322 lo_seg_contained(struct pnfs_layout_range *l1,
323 		 struct pnfs_layout_range *l2)
324 {
325 	u64 start1 = l1->offset;
326 	u64 end1 = end_offset(start1, l1->length);
327 	u64 start2 = l2->offset;
328 	u64 end2 = end_offset(start2, l2->length);
329 
330 	return (start1 <= start2) && (end1 >= end2);
331 }
332 
333 /*
334  * is l1 and l2 intersecting?
335  *   start1                             end1
336  *   [----------------------------------)
337  *                              start2           end2
338  *                              [----------------)
339  */
340 static inline int
341 lo_seg_intersecting(struct pnfs_layout_range *l1,
342 		    struct pnfs_layout_range *l2)
343 {
344 	u64 start1 = l1->offset;
345 	u64 end1 = end_offset(start1, l1->length);
346 	u64 start2 = l2->offset;
347 	u64 end2 = end_offset(start2, l2->length);
348 
349 	return (end1 == NFS4_MAX_UINT64 || end1 > start2) &&
350 	       (end2 == NFS4_MAX_UINT64 || end2 > start1);
351 }
352 
353 static bool
354 should_free_lseg(struct pnfs_layout_range *lseg_range,
355 		 struct pnfs_layout_range *recall_range)
356 {
357 	return (recall_range->iomode == IOMODE_ANY ||
358 		lseg_range->iomode == recall_range->iomode) &&
359 	       lo_seg_intersecting(lseg_range, recall_range);
360 }
361 
362 /* Returns 1 if lseg is removed from list, 0 otherwise */
363 static int mark_lseg_invalid(struct pnfs_layout_segment *lseg,
364 			     struct list_head *tmp_list)
365 {
366 	int rv = 0;
367 
368 	if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
369 		/* Remove the reference keeping the lseg in the
370 		 * list.  It will now be removed when all
371 		 * outstanding io is finished.
372 		 */
373 		dprintk("%s: lseg %p ref %d\n", __func__, lseg,
374 			atomic_read(&lseg->pls_refcount));
375 		if (atomic_dec_and_test(&lseg->pls_refcount)) {
376 			put_lseg_common(lseg);
377 			list_add(&lseg->pls_list, tmp_list);
378 			rv = 1;
379 		}
380 	}
381 	return rv;
382 }
383 
384 /* Returns count of number of matching invalid lsegs remaining in list
385  * after call.
386  */
387 int
388 mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
389 			    struct list_head *tmp_list,
390 			    struct pnfs_layout_range *recall_range)
391 {
392 	struct pnfs_layout_segment *lseg, *next;
393 	int invalid = 0, removed = 0;
394 
395 	dprintk("%s:Begin lo %p\n", __func__, lo);
396 
397 	if (list_empty(&lo->plh_segs)) {
398 		if (!test_and_set_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags))
399 			put_layout_hdr_locked(lo);
400 		return 0;
401 	}
402 	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
403 		if (!recall_range ||
404 		    should_free_lseg(&lseg->pls_range, recall_range)) {
405 			dprintk("%s: freeing lseg %p iomode %d "
406 				"offset %llu length %llu\n", __func__,
407 				lseg, lseg->pls_range.iomode, lseg->pls_range.offset,
408 				lseg->pls_range.length);
409 			invalid++;
410 			removed += mark_lseg_invalid(lseg, tmp_list);
411 		}
412 	dprintk("%s:Return %i\n", __func__, invalid - removed);
413 	return invalid - removed;
414 }
415 
416 /* note free_me must contain lsegs from a single layout_hdr */
417 void
418 pnfs_free_lseg_list(struct list_head *free_me)
419 {
420 	struct pnfs_layout_segment *lseg, *tmp;
421 	struct pnfs_layout_hdr *lo;
422 
423 	if (list_empty(free_me))
424 		return;
425 
426 	lo = list_first_entry(free_me, struct pnfs_layout_segment,
427 			      pls_list)->pls_layout;
428 
429 	if (test_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags)) {
430 		struct nfs_client *clp;
431 
432 		clp = NFS_SERVER(lo->plh_inode)->nfs_client;
433 		spin_lock(&clp->cl_lock);
434 		list_del_init(&lo->plh_layouts);
435 		spin_unlock(&clp->cl_lock);
436 	}
437 	list_for_each_entry_safe(lseg, tmp, free_me, pls_list) {
438 		list_del(&lseg->pls_list);
439 		free_lseg(lseg);
440 	}
441 }
442 
443 void
444 pnfs_destroy_layout(struct nfs_inode *nfsi)
445 {
446 	struct pnfs_layout_hdr *lo;
447 	LIST_HEAD(tmp_list);
448 
449 	spin_lock(&nfsi->vfs_inode.i_lock);
450 	lo = nfsi->layout;
451 	if (lo) {
452 		lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
453 		mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
454 	}
455 	spin_unlock(&nfsi->vfs_inode.i_lock);
456 	pnfs_free_lseg_list(&tmp_list);
457 }
458 
459 /*
460  * Called by the state manger to remove all layouts established under an
461  * expired lease.
462  */
463 void
464 pnfs_destroy_all_layouts(struct nfs_client *clp)
465 {
466 	struct nfs_server *server;
467 	struct pnfs_layout_hdr *lo;
468 	LIST_HEAD(tmp_list);
469 
470 	nfs4_deviceid_mark_client_invalid(clp);
471 	nfs4_deviceid_purge_client(clp);
472 
473 	spin_lock(&clp->cl_lock);
474 	rcu_read_lock();
475 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
476 		if (!list_empty(&server->layouts))
477 			list_splice_init(&server->layouts, &tmp_list);
478 	}
479 	rcu_read_unlock();
480 	spin_unlock(&clp->cl_lock);
481 
482 	while (!list_empty(&tmp_list)) {
483 		lo = list_entry(tmp_list.next, struct pnfs_layout_hdr,
484 				plh_layouts);
485 		dprintk("%s freeing layout for inode %lu\n", __func__,
486 			lo->plh_inode->i_ino);
487 		list_del_init(&lo->plh_layouts);
488 		pnfs_destroy_layout(NFS_I(lo->plh_inode));
489 	}
490 }
491 
492 /* update lo->plh_stateid with new if is more recent */
493 void
494 pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
495 			bool update_barrier)
496 {
497 	u32 oldseq, newseq;
498 
499 	oldseq = be32_to_cpu(lo->plh_stateid.stateid.seqid);
500 	newseq = be32_to_cpu(new->stateid.seqid);
501 	if ((int)(newseq - oldseq) > 0) {
502 		memcpy(&lo->plh_stateid, &new->stateid, sizeof(new->stateid));
503 		if (update_barrier) {
504 			u32 new_barrier = be32_to_cpu(new->stateid.seqid);
505 
506 			if ((int)(new_barrier - lo->plh_barrier))
507 				lo->plh_barrier = new_barrier;
508 		} else {
509 			/* Because of wraparound, we want to keep the barrier
510 			 * "close" to the current seqids.  It needs to be
511 			 * within 2**31 to count as "behind", so if it
512 			 * gets too near that limit, give us a litle leeway
513 			 * and bring it to within 2**30.
514 			 * NOTE - and yes, this is all unsigned arithmetic.
515 			 */
516 			if (unlikely((newseq - lo->plh_barrier) > (3 << 29)))
517 				lo->plh_barrier = newseq - (1 << 30);
518 		}
519 	}
520 }
521 
522 /* lget is set to 1 if called from inside send_layoutget call chain */
523 static bool
524 pnfs_layoutgets_blocked(struct pnfs_layout_hdr *lo, nfs4_stateid *stateid,
525 			int lget)
526 {
527 	if ((stateid) &&
528 	    (int)(lo->plh_barrier - be32_to_cpu(stateid->stateid.seqid)) >= 0)
529 		return true;
530 	return lo->plh_block_lgets ||
531 		test_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags) ||
532 		test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) ||
533 		(list_empty(&lo->plh_segs) &&
534 		 (atomic_read(&lo->plh_outstanding) > lget));
535 }
536 
537 int
538 pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
539 			      struct nfs4_state *open_state)
540 {
541 	int status = 0;
542 
543 	dprintk("--> %s\n", __func__);
544 	spin_lock(&lo->plh_inode->i_lock);
545 	if (pnfs_layoutgets_blocked(lo, NULL, 1)) {
546 		status = -EAGAIN;
547 	} else if (list_empty(&lo->plh_segs)) {
548 		int seq;
549 
550 		do {
551 			seq = read_seqbegin(&open_state->seqlock);
552 			memcpy(dst->data, open_state->stateid.data,
553 			       sizeof(open_state->stateid.data));
554 		} while (read_seqretry(&open_state->seqlock, seq));
555 	} else
556 		memcpy(dst->data, lo->plh_stateid.data, sizeof(lo->plh_stateid.data));
557 	spin_unlock(&lo->plh_inode->i_lock);
558 	dprintk("<-- %s\n", __func__);
559 	return status;
560 }
561 
562 /*
563 * Get layout from server.
564 *    for now, assume that whole file layouts are requested.
565 *    arg->offset: 0
566 *    arg->length: all ones
567 */
568 static struct pnfs_layout_segment *
569 send_layoutget(struct pnfs_layout_hdr *lo,
570 	   struct nfs_open_context *ctx,
571 	   struct pnfs_layout_range *range,
572 	   gfp_t gfp_flags)
573 {
574 	struct inode *ino = lo->plh_inode;
575 	struct nfs_server *server = NFS_SERVER(ino);
576 	struct nfs4_layoutget *lgp;
577 	struct pnfs_layout_segment *lseg = NULL;
578 	struct page **pages = NULL;
579 	int i;
580 	u32 max_resp_sz, max_pages;
581 
582 	dprintk("--> %s\n", __func__);
583 
584 	BUG_ON(ctx == NULL);
585 	lgp = kzalloc(sizeof(*lgp), gfp_flags);
586 	if (lgp == NULL)
587 		return NULL;
588 
589 	/* allocate pages for xdr post processing */
590 	max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
591 	max_pages = max_resp_sz >> PAGE_SHIFT;
592 
593 	pages = kzalloc(max_pages * sizeof(struct page *), gfp_flags);
594 	if (!pages)
595 		goto out_err_free;
596 
597 	for (i = 0; i < max_pages; i++) {
598 		pages[i] = alloc_page(gfp_flags);
599 		if (!pages[i])
600 			goto out_err_free;
601 	}
602 
603 	lgp->args.minlength = PAGE_CACHE_SIZE;
604 	if (lgp->args.minlength > range->length)
605 		lgp->args.minlength = range->length;
606 	lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
607 	lgp->args.range = *range;
608 	lgp->args.type = server->pnfs_curr_ld->id;
609 	lgp->args.inode = ino;
610 	lgp->args.ctx = get_nfs_open_context(ctx);
611 	lgp->args.layout.pages = pages;
612 	lgp->args.layout.pglen = max_pages * PAGE_SIZE;
613 	lgp->lsegpp = &lseg;
614 	lgp->gfp_flags = gfp_flags;
615 
616 	/* Synchronously retrieve layout information from server and
617 	 * store in lseg.
618 	 */
619 	nfs4_proc_layoutget(lgp);
620 	if (!lseg) {
621 		/* remember that LAYOUTGET failed and suspend trying */
622 		set_bit(lo_fail_bit(range->iomode), &lo->plh_flags);
623 	}
624 
625 	/* free xdr pages */
626 	for (i = 0; i < max_pages; i++)
627 		__free_page(pages[i]);
628 	kfree(pages);
629 
630 	return lseg;
631 
632 out_err_free:
633 	/* free any allocated xdr pages, lgp as it's not used */
634 	if (pages) {
635 		for (i = 0; i < max_pages; i++) {
636 			if (!pages[i])
637 				break;
638 			__free_page(pages[i]);
639 		}
640 		kfree(pages);
641 	}
642 	kfree(lgp);
643 	return NULL;
644 }
645 
646 /* Initiates a LAYOUTRETURN(FILE) */
647 int
648 _pnfs_return_layout(struct inode *ino)
649 {
650 	struct pnfs_layout_hdr *lo = NULL;
651 	struct nfs_inode *nfsi = NFS_I(ino);
652 	LIST_HEAD(tmp_list);
653 	struct nfs4_layoutreturn *lrp;
654 	nfs4_stateid stateid;
655 	int status = 0;
656 
657 	dprintk("--> %s\n", __func__);
658 
659 	spin_lock(&ino->i_lock);
660 	lo = nfsi->layout;
661 	if (!lo) {
662 		spin_unlock(&ino->i_lock);
663 		dprintk("%s: no layout to return\n", __func__);
664 		return status;
665 	}
666 	stateid = nfsi->layout->plh_stateid;
667 	/* Reference matched in nfs4_layoutreturn_release */
668 	get_layout_hdr(lo);
669 	mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
670 	lo->plh_block_lgets++;
671 	spin_unlock(&ino->i_lock);
672 	pnfs_free_lseg_list(&tmp_list);
673 
674 	WARN_ON(test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags));
675 
676 	lrp = kzalloc(sizeof(*lrp), GFP_KERNEL);
677 	if (unlikely(lrp == NULL)) {
678 		status = -ENOMEM;
679 		set_bit(NFS_LAYOUT_RW_FAILED, &lo->plh_flags);
680 		set_bit(NFS_LAYOUT_RO_FAILED, &lo->plh_flags);
681 		put_layout_hdr(lo);
682 		goto out;
683 	}
684 
685 	lrp->args.stateid = stateid;
686 	lrp->args.layout_type = NFS_SERVER(ino)->pnfs_curr_ld->id;
687 	lrp->args.inode = ino;
688 	lrp->args.layout = lo;
689 	lrp->clp = NFS_SERVER(ino)->nfs_client;
690 
691 	status = nfs4_proc_layoutreturn(lrp);
692 out:
693 	dprintk("<-- %s status: %d\n", __func__, status);
694 	return status;
695 }
696 
697 bool pnfs_roc(struct inode *ino)
698 {
699 	struct pnfs_layout_hdr *lo;
700 	struct pnfs_layout_segment *lseg, *tmp;
701 	LIST_HEAD(tmp_list);
702 	bool found = false;
703 
704 	spin_lock(&ino->i_lock);
705 	lo = NFS_I(ino)->layout;
706 	if (!lo || !test_and_clear_bit(NFS_LAYOUT_ROC, &lo->plh_flags) ||
707 	    test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags))
708 		goto out_nolayout;
709 	list_for_each_entry_safe(lseg, tmp, &lo->plh_segs, pls_list)
710 		if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
711 			mark_lseg_invalid(lseg, &tmp_list);
712 			found = true;
713 		}
714 	if (!found)
715 		goto out_nolayout;
716 	lo->plh_block_lgets++;
717 	get_layout_hdr(lo); /* matched in pnfs_roc_release */
718 	spin_unlock(&ino->i_lock);
719 	pnfs_free_lseg_list(&tmp_list);
720 	return true;
721 
722 out_nolayout:
723 	spin_unlock(&ino->i_lock);
724 	return false;
725 }
726 
727 void pnfs_roc_release(struct inode *ino)
728 {
729 	struct pnfs_layout_hdr *lo;
730 
731 	spin_lock(&ino->i_lock);
732 	lo = NFS_I(ino)->layout;
733 	lo->plh_block_lgets--;
734 	put_layout_hdr_locked(lo);
735 	spin_unlock(&ino->i_lock);
736 }
737 
738 void pnfs_roc_set_barrier(struct inode *ino, u32 barrier)
739 {
740 	struct pnfs_layout_hdr *lo;
741 
742 	spin_lock(&ino->i_lock);
743 	lo = NFS_I(ino)->layout;
744 	if ((int)(barrier - lo->plh_barrier) > 0)
745 		lo->plh_barrier = barrier;
746 	spin_unlock(&ino->i_lock);
747 }
748 
749 bool pnfs_roc_drain(struct inode *ino, u32 *barrier)
750 {
751 	struct nfs_inode *nfsi = NFS_I(ino);
752 	struct pnfs_layout_segment *lseg;
753 	bool found = false;
754 
755 	spin_lock(&ino->i_lock);
756 	list_for_each_entry(lseg, &nfsi->layout->plh_segs, pls_list)
757 		if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
758 			found = true;
759 			break;
760 		}
761 	if (!found) {
762 		struct pnfs_layout_hdr *lo = nfsi->layout;
763 		u32 current_seqid = be32_to_cpu(lo->plh_stateid.stateid.seqid);
764 
765 		/* Since close does not return a layout stateid for use as
766 		 * a barrier, we choose the worst-case barrier.
767 		 */
768 		*barrier = current_seqid + atomic_read(&lo->plh_outstanding);
769 	}
770 	spin_unlock(&ino->i_lock);
771 	return found;
772 }
773 
774 /*
775  * Compare two layout segments for sorting into layout cache.
776  * We want to preferentially return RW over RO layouts, so ensure those
777  * are seen first.
778  */
779 static s64
780 cmp_layout(struct pnfs_layout_range *l1,
781 	   struct pnfs_layout_range *l2)
782 {
783 	s64 d;
784 
785 	/* high offset > low offset */
786 	d = l1->offset - l2->offset;
787 	if (d)
788 		return d;
789 
790 	/* short length > long length */
791 	d = l2->length - l1->length;
792 	if (d)
793 		return d;
794 
795 	/* read > read/write */
796 	return (int)(l1->iomode == IOMODE_READ) - (int)(l2->iomode == IOMODE_READ);
797 }
798 
799 static void
800 pnfs_insert_layout(struct pnfs_layout_hdr *lo,
801 		   struct pnfs_layout_segment *lseg)
802 {
803 	struct pnfs_layout_segment *lp;
804 
805 	dprintk("%s:Begin\n", __func__);
806 
807 	assert_spin_locked(&lo->plh_inode->i_lock);
808 	list_for_each_entry(lp, &lo->plh_segs, pls_list) {
809 		if (cmp_layout(&lseg->pls_range, &lp->pls_range) > 0)
810 			continue;
811 		list_add_tail(&lseg->pls_list, &lp->pls_list);
812 		dprintk("%s: inserted lseg %p "
813 			"iomode %d offset %llu length %llu before "
814 			"lp %p iomode %d offset %llu length %llu\n",
815 			__func__, lseg, lseg->pls_range.iomode,
816 			lseg->pls_range.offset, lseg->pls_range.length,
817 			lp, lp->pls_range.iomode, lp->pls_range.offset,
818 			lp->pls_range.length);
819 		goto out;
820 	}
821 	list_add_tail(&lseg->pls_list, &lo->plh_segs);
822 	dprintk("%s: inserted lseg %p "
823 		"iomode %d offset %llu length %llu at tail\n",
824 		__func__, lseg, lseg->pls_range.iomode,
825 		lseg->pls_range.offset, lseg->pls_range.length);
826 out:
827 	get_layout_hdr(lo);
828 
829 	dprintk("%s:Return\n", __func__);
830 }
831 
832 static struct pnfs_layout_hdr *
833 alloc_init_layout_hdr(struct inode *ino,
834 		      struct nfs_open_context *ctx,
835 		      gfp_t gfp_flags)
836 {
837 	struct pnfs_layout_hdr *lo;
838 
839 	lo = pnfs_alloc_layout_hdr(ino, gfp_flags);
840 	if (!lo)
841 		return NULL;
842 	atomic_set(&lo->plh_refcount, 1);
843 	INIT_LIST_HEAD(&lo->plh_layouts);
844 	INIT_LIST_HEAD(&lo->plh_segs);
845 	INIT_LIST_HEAD(&lo->plh_bulk_recall);
846 	lo->plh_inode = ino;
847 	lo->plh_lc_cred = get_rpccred(ctx->state->owner->so_cred);
848 	return lo;
849 }
850 
851 static struct pnfs_layout_hdr *
852 pnfs_find_alloc_layout(struct inode *ino,
853 		       struct nfs_open_context *ctx,
854 		       gfp_t gfp_flags)
855 {
856 	struct nfs_inode *nfsi = NFS_I(ino);
857 	struct pnfs_layout_hdr *new = NULL;
858 
859 	dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);
860 
861 	assert_spin_locked(&ino->i_lock);
862 	if (nfsi->layout) {
863 		if (test_bit(NFS_LAYOUT_DESTROYED, &nfsi->layout->plh_flags))
864 			return NULL;
865 		else
866 			return nfsi->layout;
867 	}
868 	spin_unlock(&ino->i_lock);
869 	new = alloc_init_layout_hdr(ino, ctx, gfp_flags);
870 	spin_lock(&ino->i_lock);
871 
872 	if (likely(nfsi->layout == NULL))	/* Won the race? */
873 		nfsi->layout = new;
874 	else
875 		pnfs_free_layout_hdr(new);
876 	return nfsi->layout;
877 }
878 
879 /*
880  * iomode matching rules:
881  * iomode	lseg	match
882  * -----	-----	-----
883  * ANY		READ	true
884  * ANY		RW	true
885  * RW		READ	false
886  * RW		RW	true
887  * READ		READ	true
888  * READ		RW	true
889  */
890 static int
891 is_matching_lseg(struct pnfs_layout_range *ls_range,
892 		 struct pnfs_layout_range *range)
893 {
894 	struct pnfs_layout_range range1;
895 
896 	if ((range->iomode == IOMODE_RW &&
897 	     ls_range->iomode != IOMODE_RW) ||
898 	    !lo_seg_intersecting(ls_range, range))
899 		return 0;
900 
901 	/* range1 covers only the first byte in the range */
902 	range1 = *range;
903 	range1.length = 1;
904 	return lo_seg_contained(ls_range, &range1);
905 }
906 
907 /*
908  * lookup range in layout
909  */
910 static struct pnfs_layout_segment *
911 pnfs_find_lseg(struct pnfs_layout_hdr *lo,
912 		struct pnfs_layout_range *range)
913 {
914 	struct pnfs_layout_segment *lseg, *ret = NULL;
915 
916 	dprintk("%s:Begin\n", __func__);
917 
918 	assert_spin_locked(&lo->plh_inode->i_lock);
919 	list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
920 		if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
921 		    is_matching_lseg(&lseg->pls_range, range)) {
922 			ret = get_lseg(lseg);
923 			break;
924 		}
925 		if (lseg->pls_range.offset > range->offset)
926 			break;
927 	}
928 
929 	dprintk("%s:Return lseg %p ref %d\n",
930 		__func__, ret, ret ? atomic_read(&ret->pls_refcount) : 0);
931 	return ret;
932 }
933 
934 /*
935  * Layout segment is retreived from the server if not cached.
936  * The appropriate layout segment is referenced and returned to the caller.
937  */
938 struct pnfs_layout_segment *
939 pnfs_update_layout(struct inode *ino,
940 		   struct nfs_open_context *ctx,
941 		   loff_t pos,
942 		   u64 count,
943 		   enum pnfs_iomode iomode,
944 		   gfp_t gfp_flags)
945 {
946 	struct pnfs_layout_range arg = {
947 		.iomode = iomode,
948 		.offset = pos,
949 		.length = count,
950 	};
951 	unsigned pg_offset;
952 	struct nfs_inode *nfsi = NFS_I(ino);
953 	struct nfs_server *server = NFS_SERVER(ino);
954 	struct nfs_client *clp = server->nfs_client;
955 	struct pnfs_layout_hdr *lo;
956 	struct pnfs_layout_segment *lseg = NULL;
957 	bool first = false;
958 
959 	if (!pnfs_enabled_sb(NFS_SERVER(ino)))
960 		return NULL;
961 	spin_lock(&ino->i_lock);
962 	lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
963 	if (lo == NULL) {
964 		dprintk("%s ERROR: can't get pnfs_layout_hdr\n", __func__);
965 		goto out_unlock;
966 	}
967 
968 	/* Do we even need to bother with this? */
969 	if (test_bit(NFS4CLNT_LAYOUTRECALL, &clp->cl_state) ||
970 	    test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
971 		dprintk("%s matches recall, use MDS\n", __func__);
972 		goto out_unlock;
973 	}
974 
975 	/* if LAYOUTGET already failed once we don't try again */
976 	if (test_bit(lo_fail_bit(iomode), &nfsi->layout->plh_flags))
977 		goto out_unlock;
978 
979 	/* Check to see if the layout for the given range already exists */
980 	lseg = pnfs_find_lseg(lo, &arg);
981 	if (lseg)
982 		goto out_unlock;
983 
984 	if (pnfs_layoutgets_blocked(lo, NULL, 0))
985 		goto out_unlock;
986 	atomic_inc(&lo->plh_outstanding);
987 
988 	get_layout_hdr(lo);
989 	if (list_empty(&lo->plh_segs))
990 		first = true;
991 	spin_unlock(&ino->i_lock);
992 	if (first) {
993 		/* The lo must be on the clp list if there is any
994 		 * chance of a CB_LAYOUTRECALL(FILE) coming in.
995 		 */
996 		spin_lock(&clp->cl_lock);
997 		BUG_ON(!list_empty(&lo->plh_layouts));
998 		list_add_tail(&lo->plh_layouts, &server->layouts);
999 		spin_unlock(&clp->cl_lock);
1000 	}
1001 
1002 	pg_offset = arg.offset & ~PAGE_CACHE_MASK;
1003 	if (pg_offset) {
1004 		arg.offset -= pg_offset;
1005 		arg.length += pg_offset;
1006 	}
1007 	if (arg.length != NFS4_MAX_UINT64)
1008 		arg.length = PAGE_CACHE_ALIGN(arg.length);
1009 
1010 	lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
1011 	if (!lseg && first) {
1012 		spin_lock(&clp->cl_lock);
1013 		list_del_init(&lo->plh_layouts);
1014 		spin_unlock(&clp->cl_lock);
1015 	}
1016 	atomic_dec(&lo->plh_outstanding);
1017 	put_layout_hdr(lo);
1018 out:
1019 	dprintk("%s end, state 0x%lx lseg %p\n", __func__,
1020 		nfsi->layout ? nfsi->layout->plh_flags : -1, lseg);
1021 	return lseg;
1022 out_unlock:
1023 	spin_unlock(&ino->i_lock);
1024 	goto out;
1025 }
1026 EXPORT_SYMBOL_GPL(pnfs_update_layout);
1027 
1028 int
1029 pnfs_layout_process(struct nfs4_layoutget *lgp)
1030 {
1031 	struct pnfs_layout_hdr *lo = NFS_I(lgp->args.inode)->layout;
1032 	struct nfs4_layoutget_res *res = &lgp->res;
1033 	struct pnfs_layout_segment *lseg;
1034 	struct inode *ino = lo->plh_inode;
1035 	struct nfs_client *clp = NFS_SERVER(ino)->nfs_client;
1036 	int status = 0;
1037 
1038 	/* Inject layout blob into I/O device driver */
1039 	lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res, lgp->gfp_flags);
1040 	if (!lseg || IS_ERR(lseg)) {
1041 		if (!lseg)
1042 			status = -ENOMEM;
1043 		else
1044 			status = PTR_ERR(lseg);
1045 		dprintk("%s: Could not allocate layout: error %d\n",
1046 		       __func__, status);
1047 		goto out;
1048 	}
1049 
1050 	spin_lock(&ino->i_lock);
1051 	if (test_bit(NFS4CLNT_LAYOUTRECALL, &clp->cl_state) ||
1052 	    test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1053 		dprintk("%s forget reply due to recall\n", __func__);
1054 		goto out_forget_reply;
1055 	}
1056 
1057 	if (pnfs_layoutgets_blocked(lo, &res->stateid, 1)) {
1058 		dprintk("%s forget reply due to state\n", __func__);
1059 		goto out_forget_reply;
1060 	}
1061 	init_lseg(lo, lseg);
1062 	lseg->pls_range = res->range;
1063 	*lgp->lsegpp = get_lseg(lseg);
1064 	pnfs_insert_layout(lo, lseg);
1065 
1066 	if (res->return_on_close) {
1067 		set_bit(NFS_LSEG_ROC, &lseg->pls_flags);
1068 		set_bit(NFS_LAYOUT_ROC, &lo->plh_flags);
1069 	}
1070 
1071 	/* Done processing layoutget. Set the layout stateid */
1072 	pnfs_set_layout_stateid(lo, &res->stateid, false);
1073 	spin_unlock(&ino->i_lock);
1074 out:
1075 	return status;
1076 
1077 out_forget_reply:
1078 	spin_unlock(&ino->i_lock);
1079 	lseg->pls_layout = lo;
1080 	NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
1081 	goto out;
1082 }
1083 
1084 void
1085 pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
1086 {
1087 	BUG_ON(pgio->pg_lseg != NULL);
1088 
1089 	pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
1090 					   req->wb_context,
1091 					   req_offset(req),
1092 					   req->wb_bytes,
1093 					   IOMODE_READ,
1094 					   GFP_KERNEL);
1095 	/* If no lseg, fall back to read through mds */
1096 	if (pgio->pg_lseg == NULL)
1097 		nfs_pageio_reset_read_mds(pgio);
1098 
1099 }
1100 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_read);
1101 
1102 void
1103 pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
1104 {
1105 	BUG_ON(pgio->pg_lseg != NULL);
1106 
1107 	pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
1108 					   req->wb_context,
1109 					   req_offset(req),
1110 					   req->wb_bytes,
1111 					   IOMODE_RW,
1112 					   GFP_NOFS);
1113 	/* If no lseg, fall back to write through mds */
1114 	if (pgio->pg_lseg == NULL)
1115 		nfs_pageio_reset_write_mds(pgio);
1116 }
1117 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
1118 
1119 bool
1120 pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode)
1121 {
1122 	struct nfs_server *server = NFS_SERVER(inode);
1123 	struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
1124 
1125 	if (ld == NULL)
1126 		return false;
1127 	nfs_pageio_init(pgio, inode, ld->pg_read_ops, server->rsize, 0);
1128 	return true;
1129 }
1130 
1131 bool
1132 pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode, int ioflags)
1133 {
1134 	struct nfs_server *server = NFS_SERVER(inode);
1135 	struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
1136 
1137 	if (ld == NULL)
1138 		return false;
1139 	nfs_pageio_init(pgio, inode, ld->pg_write_ops, server->wsize, ioflags);
1140 	return true;
1141 }
1142 
1143 bool
1144 pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
1145 		     struct nfs_page *req)
1146 {
1147 	if (pgio->pg_lseg == NULL)
1148 		return nfs_generic_pg_test(pgio, prev, req);
1149 
1150 	/*
1151 	 * Test if a nfs_page is fully contained in the pnfs_layout_range.
1152 	 * Note that this test makes several assumptions:
1153 	 * - that the previous nfs_page in the struct nfs_pageio_descriptor
1154 	 *   is known to lie within the range.
1155 	 *   - that the nfs_page being tested is known to be contiguous with the
1156 	 *   previous nfs_page.
1157 	 *   - Layout ranges are page aligned, so we only have to test the
1158 	 *   start offset of the request.
1159 	 *
1160 	 * Please also note that 'end_offset' is actually the offset of the
1161 	 * first byte that lies outside the pnfs_layout_range. FIXME?
1162 	 *
1163 	 */
1164 	return req_offset(req) < end_offset(pgio->pg_lseg->pls_range.offset,
1165 					 pgio->pg_lseg->pls_range.length);
1166 }
1167 EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);
1168 
1169 /*
1170  * Called by non rpc-based layout drivers
1171  */
1172 void pnfs_ld_write_done(struct nfs_write_data *data)
1173 {
1174 	if (likely(!data->pnfs_error)) {
1175 		pnfs_set_layoutcommit(data);
1176 		data->mds_ops->rpc_call_done(&data->task, data);
1177 	} else {
1178 		put_lseg(data->lseg);
1179 		data->lseg = NULL;
1180 		dprintk("pnfs write error = %d\n", data->pnfs_error);
1181 	}
1182 	data->mds_ops->rpc_release(data);
1183 }
1184 EXPORT_SYMBOL_GPL(pnfs_ld_write_done);
1185 
1186 static void
1187 pnfs_write_through_mds(struct nfs_pageio_descriptor *desc,
1188 		struct nfs_write_data *data)
1189 {
1190 	list_splice_tail_init(&data->pages, &desc->pg_list);
1191 	if (data->req && list_empty(&data->req->wb_list))
1192 		nfs_list_add_request(data->req, &desc->pg_list);
1193 	nfs_pageio_reset_write_mds(desc);
1194 	desc->pg_recoalesce = 1;
1195 	nfs_writedata_release(data);
1196 }
1197 
1198 static enum pnfs_try_status
1199 pnfs_try_to_write_data(struct nfs_write_data *wdata,
1200 			const struct rpc_call_ops *call_ops,
1201 			struct pnfs_layout_segment *lseg,
1202 			int how)
1203 {
1204 	struct inode *inode = wdata->inode;
1205 	enum pnfs_try_status trypnfs;
1206 	struct nfs_server *nfss = NFS_SERVER(inode);
1207 
1208 	wdata->mds_ops = call_ops;
1209 	wdata->lseg = get_lseg(lseg);
1210 
1211 	dprintk("%s: Writing ino:%lu %u@%llu (how %d)\n", __func__,
1212 		inode->i_ino, wdata->args.count, wdata->args.offset, how);
1213 
1214 	trypnfs = nfss->pnfs_curr_ld->write_pagelist(wdata, how);
1215 	if (trypnfs == PNFS_NOT_ATTEMPTED) {
1216 		put_lseg(wdata->lseg);
1217 		wdata->lseg = NULL;
1218 	} else
1219 		nfs_inc_stats(inode, NFSIOS_PNFS_WRITE);
1220 
1221 	dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
1222 	return trypnfs;
1223 }
1224 
1225 static void
1226 pnfs_do_multiple_writes(struct nfs_pageio_descriptor *desc, struct list_head *head, int how)
1227 {
1228 	struct nfs_write_data *data;
1229 	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
1230 	struct pnfs_layout_segment *lseg = desc->pg_lseg;
1231 
1232 	desc->pg_lseg = NULL;
1233 	while (!list_empty(head)) {
1234 		enum pnfs_try_status trypnfs;
1235 
1236 		data = list_entry(head->next, struct nfs_write_data, list);
1237 		list_del_init(&data->list);
1238 
1239 		trypnfs = pnfs_try_to_write_data(data, call_ops, lseg, how);
1240 		if (trypnfs == PNFS_NOT_ATTEMPTED)
1241 			pnfs_write_through_mds(desc, data);
1242 	}
1243 	put_lseg(lseg);
1244 }
1245 
1246 int
1247 pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
1248 {
1249 	LIST_HEAD(head);
1250 	int ret;
1251 
1252 	ret = nfs_generic_flush(desc, &head);
1253 	if (ret != 0) {
1254 		put_lseg(desc->pg_lseg);
1255 		desc->pg_lseg = NULL;
1256 		return ret;
1257 	}
1258 	pnfs_do_multiple_writes(desc, &head, desc->pg_ioflags);
1259 	return 0;
1260 }
1261 EXPORT_SYMBOL_GPL(pnfs_generic_pg_writepages);
1262 
1263 /*
1264  * Called by non rpc-based layout drivers
1265  */
1266 void pnfs_ld_read_done(struct nfs_read_data *data)
1267 {
1268 	if (likely(!data->pnfs_error)) {
1269 		__nfs4_read_done_cb(data);
1270 		data->mds_ops->rpc_call_done(&data->task, data);
1271 	} else {
1272 		put_lseg(data->lseg);
1273 		data->lseg = NULL;
1274 		dprintk("pnfs write error = %d\n", data->pnfs_error);
1275 	}
1276 	data->mds_ops->rpc_release(data);
1277 }
1278 EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
1279 
1280 static void
1281 pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
1282 		struct nfs_read_data *data)
1283 {
1284 	list_splice_tail_init(&data->pages, &desc->pg_list);
1285 	if (data->req && list_empty(&data->req->wb_list))
1286 		nfs_list_add_request(data->req, &desc->pg_list);
1287 	nfs_pageio_reset_read_mds(desc);
1288 	desc->pg_recoalesce = 1;
1289 	nfs_readdata_release(data);
1290 }
1291 
1292 /*
1293  * Call the appropriate parallel I/O subsystem read function.
1294  */
1295 static enum pnfs_try_status
1296 pnfs_try_to_read_data(struct nfs_read_data *rdata,
1297 		       const struct rpc_call_ops *call_ops,
1298 		       struct pnfs_layout_segment *lseg)
1299 {
1300 	struct inode *inode = rdata->inode;
1301 	struct nfs_server *nfss = NFS_SERVER(inode);
1302 	enum pnfs_try_status trypnfs;
1303 
1304 	rdata->mds_ops = call_ops;
1305 	rdata->lseg = get_lseg(lseg);
1306 
1307 	dprintk("%s: Reading ino:%lu %u@%llu\n",
1308 		__func__, inode->i_ino, rdata->args.count, rdata->args.offset);
1309 
1310 	trypnfs = nfss->pnfs_curr_ld->read_pagelist(rdata);
1311 	if (trypnfs == PNFS_NOT_ATTEMPTED) {
1312 		put_lseg(rdata->lseg);
1313 		rdata->lseg = NULL;
1314 	} else {
1315 		nfs_inc_stats(inode, NFSIOS_PNFS_READ);
1316 	}
1317 	dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
1318 	return trypnfs;
1319 }
1320 
1321 static void
1322 pnfs_do_multiple_reads(struct nfs_pageio_descriptor *desc, struct list_head *head)
1323 {
1324 	struct nfs_read_data *data;
1325 	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
1326 	struct pnfs_layout_segment *lseg = desc->pg_lseg;
1327 
1328 	desc->pg_lseg = NULL;
1329 	while (!list_empty(head)) {
1330 		enum pnfs_try_status trypnfs;
1331 
1332 		data = list_entry(head->next, struct nfs_read_data, list);
1333 		list_del_init(&data->list);
1334 
1335 		trypnfs = pnfs_try_to_read_data(data, call_ops, lseg);
1336 		if (trypnfs == PNFS_NOT_ATTEMPTED)
1337 			pnfs_read_through_mds(desc, data);
1338 	}
1339 	put_lseg(lseg);
1340 }
1341 
1342 int
1343 pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
1344 {
1345 	LIST_HEAD(head);
1346 	int ret;
1347 
1348 	ret = nfs_generic_pagein(desc, &head);
1349 	if (ret != 0) {
1350 		put_lseg(desc->pg_lseg);
1351 		desc->pg_lseg = NULL;
1352 		return ret;
1353 	}
1354 	pnfs_do_multiple_reads(desc, &head);
1355 	return 0;
1356 }
1357 EXPORT_SYMBOL_GPL(pnfs_generic_pg_readpages);
1358 
1359 /*
1360  * There can be multiple RW segments.
1361  */
1362 static void pnfs_list_write_lseg(struct inode *inode, struct list_head *listp)
1363 {
1364 	struct pnfs_layout_segment *lseg;
1365 
1366 	list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) {
1367 		if (lseg->pls_range.iomode == IOMODE_RW &&
1368 		    test_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
1369 			list_add(&lseg->pls_lc_list, listp);
1370 	}
1371 }
1372 
1373 void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg)
1374 {
1375 	if (lseg->pls_range.iomode == IOMODE_RW) {
1376 		dprintk("%s Setting layout IOMODE_RW fail bit\n", __func__);
1377 		set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
1378 	} else {
1379 		dprintk("%s Setting layout IOMODE_READ fail bit\n", __func__);
1380 		set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
1381 	}
1382 }
1383 EXPORT_SYMBOL_GPL(pnfs_set_lo_fail);
1384 
1385 void
1386 pnfs_set_layoutcommit(struct nfs_write_data *wdata)
1387 {
1388 	struct nfs_inode *nfsi = NFS_I(wdata->inode);
1389 	loff_t end_pos = wdata->mds_offset + wdata->res.count;
1390 	bool mark_as_dirty = false;
1391 
1392 	spin_lock(&nfsi->vfs_inode.i_lock);
1393 	if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
1394 		mark_as_dirty = true;
1395 		dprintk("%s: Set layoutcommit for inode %lu ",
1396 			__func__, wdata->inode->i_ino);
1397 	}
1398 	if (!test_and_set_bit(NFS_LSEG_LAYOUTCOMMIT, &wdata->lseg->pls_flags)) {
1399 		/* references matched in nfs4_layoutcommit_release */
1400 		get_lseg(wdata->lseg);
1401 	}
1402 	if (end_pos > nfsi->layout->plh_lwb)
1403 		nfsi->layout->plh_lwb = end_pos;
1404 	spin_unlock(&nfsi->vfs_inode.i_lock);
1405 	dprintk("%s: lseg %p end_pos %llu\n",
1406 		__func__, wdata->lseg, nfsi->layout->plh_lwb);
1407 
1408 	/* if pnfs_layoutcommit_inode() runs between inode locks, the next one
1409 	 * will be a noop because NFS_INO_LAYOUTCOMMIT will not be set */
1410 	if (mark_as_dirty)
1411 		mark_inode_dirty_sync(wdata->inode);
1412 }
1413 EXPORT_SYMBOL_GPL(pnfs_set_layoutcommit);
1414 
1415 void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data)
1416 {
1417 	struct nfs_server *nfss = NFS_SERVER(data->args.inode);
1418 
1419 	if (nfss->pnfs_curr_ld->cleanup_layoutcommit)
1420 		nfss->pnfs_curr_ld->cleanup_layoutcommit(data);
1421 }
1422 
1423 /*
1424  * For the LAYOUT4_NFSV4_1_FILES layout type, NFS_DATA_SYNC WRITEs and
1425  * NFS_UNSTABLE WRITEs with a COMMIT to data servers must store enough
1426  * data to disk to allow the server to recover the data if it crashes.
1427  * LAYOUTCOMMIT is only needed when the NFL4_UFLG_COMMIT_THRU_MDS flag
1428  * is off, and a COMMIT is sent to a data server, or
1429  * if WRITEs to a data server return NFS_DATA_SYNC.
1430  */
1431 int
1432 pnfs_layoutcommit_inode(struct inode *inode, bool sync)
1433 {
1434 	struct nfs4_layoutcommit_data *data;
1435 	struct nfs_inode *nfsi = NFS_I(inode);
1436 	loff_t end_pos;
1437 	int status = 0;
1438 
1439 	dprintk("--> %s inode %lu\n", __func__, inode->i_ino);
1440 
1441 	if (!test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
1442 		return 0;
1443 
1444 	/* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
1445 	data = kzalloc(sizeof(*data), GFP_NOFS);
1446 	if (!data) {
1447 		status = -ENOMEM;
1448 		goto out;
1449 	}
1450 
1451 	if (!test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
1452 		goto out_free;
1453 
1454 	if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
1455 		if (!sync) {
1456 			status = -EAGAIN;
1457 			goto out_free;
1458 		}
1459 		status = wait_on_bit_lock(&nfsi->flags, NFS_INO_LAYOUTCOMMITTING,
1460 					nfs_wait_bit_killable, TASK_KILLABLE);
1461 		if (status)
1462 			goto out_free;
1463 	}
1464 
1465 	INIT_LIST_HEAD(&data->lseg_list);
1466 	spin_lock(&inode->i_lock);
1467 	if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
1468 		clear_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags);
1469 		spin_unlock(&inode->i_lock);
1470 		wake_up_bit(&nfsi->flags, NFS_INO_LAYOUTCOMMITTING);
1471 		goto out_free;
1472 	}
1473 
1474 	pnfs_list_write_lseg(inode, &data->lseg_list);
1475 
1476 	end_pos = nfsi->layout->plh_lwb;
1477 	nfsi->layout->plh_lwb = 0;
1478 
1479 	memcpy(&data->args.stateid.data, nfsi->layout->plh_stateid.data,
1480 		sizeof(nfsi->layout->plh_stateid.data));
1481 	spin_unlock(&inode->i_lock);
1482 
1483 	data->args.inode = inode;
1484 	data->cred = get_rpccred(nfsi->layout->plh_lc_cred);
1485 	nfs_fattr_init(&data->fattr);
1486 	data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
1487 	data->res.fattr = &data->fattr;
1488 	data->args.lastbytewritten = end_pos - 1;
1489 	data->res.server = NFS_SERVER(inode);
1490 
1491 	status = nfs4_proc_layoutcommit(data, sync);
1492 out:
1493 	if (status)
1494 		mark_inode_dirty_sync(inode);
1495 	dprintk("<-- %s status %d\n", __func__, status);
1496 	return status;
1497 out_free:
1498 	kfree(data);
1499 	goto out;
1500 }
1501