xref: /linux/fs/nfs/pnfs.c (revision 55f1b540d893da740a81200450014c45a8103f54)
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 <linux/sort.h>
34 #include "internal.h"
35 #include "pnfs.h"
36 #include "iostat.h"
37 #include "nfs4trace.h"
38 #include "delegation.h"
39 #include "nfs42.h"
40 #include "nfs4_fs.h"
41 
42 #define NFSDBG_FACILITY		NFSDBG_PNFS
43 #define PNFS_LAYOUTGET_RETRY_TIMEOUT (120*HZ)
44 
45 /* Locking:
46  *
47  * pnfs_spinlock:
48  *      protects pnfs_modules_tbl.
49  */
50 static DEFINE_SPINLOCK(pnfs_spinlock);
51 
52 /*
53  * pnfs_modules_tbl holds all pnfs modules
54  */
55 static LIST_HEAD(pnfs_modules_tbl);
56 
57 static void pnfs_layoutreturn_before_put_layout_hdr(struct pnfs_layout_hdr *lo);
58 static void pnfs_free_returned_lsegs(struct pnfs_layout_hdr *lo,
59 		struct list_head *free_me,
60 		const struct pnfs_layout_range *range,
61 		u32 seq);
62 static bool pnfs_lseg_dec_and_remove_zero(struct pnfs_layout_segment *lseg,
63 		                struct list_head *tmp_list);
64 static int pnfs_layout_return_on_reboot(struct pnfs_layout_hdr *lo);
65 
66 /* Return the registered pnfs layout driver module matching given id */
67 static struct pnfs_layoutdriver_type *
68 find_pnfs_driver_locked(u32 id)
69 {
70 	struct pnfs_layoutdriver_type *local;
71 
72 	list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid)
73 		if (local->id == id)
74 			goto out;
75 	local = NULL;
76 out:
77 	dprintk("%s: Searching for id %u, found %p\n", __func__, id, local);
78 	return local;
79 }
80 
81 static struct pnfs_layoutdriver_type *
82 find_pnfs_driver(u32 id)
83 {
84 	struct pnfs_layoutdriver_type *local;
85 
86 	spin_lock(&pnfs_spinlock);
87 	local = find_pnfs_driver_locked(id);
88 	if (local != NULL && !try_module_get(local->owner)) {
89 		dprintk("%s: Could not grab reference on module\n", __func__);
90 		local = NULL;
91 	}
92 	spin_unlock(&pnfs_spinlock);
93 	return local;
94 }
95 
96 const struct pnfs_layoutdriver_type *pnfs_find_layoutdriver(u32 id)
97 {
98 	return find_pnfs_driver(id);
99 }
100 
101 void pnfs_put_layoutdriver(const struct pnfs_layoutdriver_type *ld)
102 {
103 	if (ld)
104 		module_put(ld->owner);
105 }
106 
107 void
108 unset_pnfs_layoutdriver(struct nfs_server *nfss)
109 {
110 	if (nfss->pnfs_curr_ld) {
111 		if (nfss->pnfs_curr_ld->clear_layoutdriver)
112 			nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
113 		/* Decrement the MDS count. Purge the deviceid cache if zero */
114 		if (atomic_dec_and_test(&nfss->nfs_client->cl_mds_count))
115 			nfs4_deviceid_purge_client(nfss->nfs_client);
116 		module_put(nfss->pnfs_curr_ld->owner);
117 	}
118 	nfss->pnfs_curr_ld = NULL;
119 }
120 
121 /*
122  * When the server sends a list of layout types, we choose one in the order
123  * given in the list below.
124  *
125  * FIXME: should this list be configurable in some fashion? module param?
126  * 	  mount option? something else?
127  */
128 static const u32 ld_prefs[] = {
129 	LAYOUT_SCSI,
130 	LAYOUT_BLOCK_VOLUME,
131 	LAYOUT_OSD2_OBJECTS,
132 	LAYOUT_FLEX_FILES,
133 	LAYOUT_NFSV4_1_FILES,
134 	0
135 };
136 
137 static int
138 ld_cmp(const void *e1, const void *e2)
139 {
140 	u32 ld1 = *((u32 *)e1);
141 	u32 ld2 = *((u32 *)e2);
142 	int i;
143 
144 	for (i = 0; ld_prefs[i] != 0; i++) {
145 		if (ld1 == ld_prefs[i])
146 			return -1;
147 
148 		if (ld2 == ld_prefs[i])
149 			return 1;
150 	}
151 	return 0;
152 }
153 
154 /*
155  * Try to set the server's pnfs module to the pnfs layout type specified by id.
156  * Currently only one pNFS layout driver per filesystem is supported.
157  *
158  * @ids array of layout types supported by MDS.
159  */
160 void
161 set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
162 		      struct nfs_fsinfo *fsinfo)
163 {
164 	struct pnfs_layoutdriver_type *ld_type = NULL;
165 	u32 id;
166 	int i;
167 
168 	if (fsinfo->nlayouttypes == 0)
169 		goto out_no_driver;
170 	if (!(server->nfs_client->cl_exchange_flags &
171 		 (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) {
172 		printk(KERN_ERR "NFS: %s: cl_exchange_flags 0x%x\n",
173 			__func__, server->nfs_client->cl_exchange_flags);
174 		goto out_no_driver;
175 	}
176 
177 	sort(fsinfo->layouttype, fsinfo->nlayouttypes,
178 		sizeof(*fsinfo->layouttype), ld_cmp, NULL);
179 
180 	for (i = 0; i < fsinfo->nlayouttypes; i++) {
181 		id = fsinfo->layouttype[i];
182 		ld_type = find_pnfs_driver(id);
183 		if (!ld_type) {
184 			request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX,
185 					id);
186 			ld_type = find_pnfs_driver(id);
187 		}
188 		if (ld_type)
189 			break;
190 	}
191 
192 	if (!ld_type) {
193 		dprintk("%s: No pNFS module found!\n", __func__);
194 		goto out_no_driver;
195 	}
196 
197 	server->pnfs_curr_ld = ld_type;
198 	if (ld_type->set_layoutdriver
199 	    && ld_type->set_layoutdriver(server, mntfh)) {
200 		printk(KERN_ERR "NFS: %s: Error initializing pNFS layout "
201 			"driver %u.\n", __func__, id);
202 		module_put(ld_type->owner);
203 		goto out_no_driver;
204 	}
205 	/* Bump the MDS count */
206 	atomic_inc(&server->nfs_client->cl_mds_count);
207 
208 	dprintk("%s: pNFS module for %u set\n", __func__, id);
209 	return;
210 
211 out_no_driver:
212 	dprintk("%s: Using NFSv4 I/O\n", __func__);
213 	server->pnfs_curr_ld = NULL;
214 }
215 
216 int
217 pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
218 {
219 	int status = -EINVAL;
220 	struct pnfs_layoutdriver_type *tmp;
221 
222 	if (ld_type->id == 0) {
223 		printk(KERN_ERR "NFS: %s id 0 is reserved\n", __func__);
224 		return status;
225 	}
226 	if (!ld_type->alloc_lseg || !ld_type->free_lseg) {
227 		printk(KERN_ERR "NFS: %s Layout driver must provide "
228 		       "alloc_lseg and free_lseg.\n", __func__);
229 		return status;
230 	}
231 
232 	spin_lock(&pnfs_spinlock);
233 	tmp = find_pnfs_driver_locked(ld_type->id);
234 	if (!tmp) {
235 		list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl);
236 		status = 0;
237 		dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id,
238 			ld_type->name);
239 	} else {
240 		printk(KERN_ERR "NFS: %s Module with id %d already loaded!\n",
241 			__func__, ld_type->id);
242 	}
243 	spin_unlock(&pnfs_spinlock);
244 
245 	return status;
246 }
247 EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver);
248 
249 void
250 pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
251 {
252 	dprintk("%s Deregistering id:%u\n", __func__, ld_type->id);
253 	spin_lock(&pnfs_spinlock);
254 	list_del(&ld_type->pnfs_tblid);
255 	spin_unlock(&pnfs_spinlock);
256 }
257 EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);
258 
259 /*
260  * pNFS client layout cache
261  */
262 
263 /* Need to hold i_lock if caller does not already hold reference */
264 void
265 pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo)
266 {
267 	refcount_inc(&lo->plh_refcount);
268 }
269 
270 static struct pnfs_layout_hdr *
271 pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
272 {
273 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
274 	return ld->alloc_layout_hdr(ino, gfp_flags);
275 }
276 
277 static void
278 pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
279 {
280 	struct nfs_server *server = NFS_SERVER(lo->plh_inode);
281 	struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
282 
283 	if (test_and_clear_bit(NFS_LAYOUT_HASHED, &lo->plh_flags)) {
284 		struct nfs_client *clp = server->nfs_client;
285 
286 		spin_lock(&clp->cl_lock);
287 		list_del_rcu(&lo->plh_layouts);
288 		spin_unlock(&clp->cl_lock);
289 	}
290 	put_cred(lo->plh_lc_cred);
291 	return ld->free_layout_hdr(lo);
292 }
293 
294 static void
295 pnfs_detach_layout_hdr(struct pnfs_layout_hdr *lo)
296 {
297 	struct nfs_inode *nfsi = NFS_I(lo->plh_inode);
298 	dprintk("%s: freeing layout cache %p\n", __func__, lo);
299 	nfsi->layout = NULL;
300 	/* Reset MDS Threshold I/O counters */
301 	nfsi->write_io = 0;
302 	nfsi->read_io = 0;
303 }
304 
305 void
306 pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
307 {
308 	struct inode *inode;
309 	unsigned long i_state;
310 
311 	if (!lo)
312 		return;
313 	inode = lo->plh_inode;
314 	pnfs_layoutreturn_before_put_layout_hdr(lo);
315 
316 	if (refcount_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
317 		if (!list_empty(&lo->plh_segs))
318 			WARN_ONCE(1, "NFS: BUG unfreed layout segments.\n");
319 		pnfs_detach_layout_hdr(lo);
320 		i_state = inode->i_state;
321 		spin_unlock(&inode->i_lock);
322 		pnfs_free_layout_hdr(lo);
323 		/* Notify pnfs_destroy_layout_final() that we're done */
324 		if (i_state & (I_FREEING | I_CLEAR))
325 			wake_up_var(lo);
326 	}
327 }
328 
329 static struct inode *
330 pnfs_grab_inode_layout_hdr(struct pnfs_layout_hdr *lo)
331 {
332 	struct inode *inode = igrab(lo->plh_inode);
333 	if (inode)
334 		return inode;
335 	set_bit(NFS_LAYOUT_INODE_FREEING, &lo->plh_flags);
336 	return NULL;
337 }
338 
339 /*
340  * Compare 2 layout stateid sequence ids, to see which is newer,
341  * taking into account wraparound issues.
342  */
343 static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
344 {
345 	return (s32)(s1 - s2) > 0;
346 }
347 
348 static void pnfs_barrier_update(struct pnfs_layout_hdr *lo, u32 newseq)
349 {
350 	if (pnfs_seqid_is_newer(newseq, lo->plh_barrier) || !lo->plh_barrier)
351 		lo->plh_barrier = newseq;
352 }
353 
354 static void
355 pnfs_set_plh_return_info(struct pnfs_layout_hdr *lo, enum pnfs_iomode iomode,
356 			 u32 seq)
357 {
358 	if (lo->plh_return_iomode != 0 && lo->plh_return_iomode != iomode)
359 		iomode = IOMODE_ANY;
360 	lo->plh_return_iomode = iomode;
361 	set_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags);
362 	/*
363 	 * We must set lo->plh_return_seq to avoid livelocks with
364 	 * pnfs_layout_need_return()
365 	 */
366 	if (seq == 0)
367 		seq = be32_to_cpu(lo->plh_stateid.seqid);
368 	if (!lo->plh_return_seq || pnfs_seqid_is_newer(seq, lo->plh_return_seq))
369 		lo->plh_return_seq = seq;
370 	pnfs_barrier_update(lo, seq);
371 }
372 
373 static void
374 pnfs_clear_layoutreturn_info(struct pnfs_layout_hdr *lo)
375 {
376 	struct pnfs_layout_segment *lseg;
377 	lo->plh_return_iomode = 0;
378 	lo->plh_return_seq = 0;
379 	clear_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags);
380 	list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
381 		if (!test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
382 			continue;
383 		pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
384 	}
385 }
386 
387 static void pnfs_clear_layoutreturn_waitbit(struct pnfs_layout_hdr *lo)
388 {
389 	clear_bit_unlock(NFS_LAYOUT_RETURN, &lo->plh_flags);
390 	clear_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags);
391 	smp_mb__after_atomic();
392 	wake_up_bit(&lo->plh_flags, NFS_LAYOUT_RETURN);
393 	rpc_wake_up(&NFS_SERVER(lo->plh_inode)->roc_rpcwaitq);
394 }
395 
396 static void
397 pnfs_clear_lseg_state(struct pnfs_layout_segment *lseg,
398 		struct list_head *free_me)
399 {
400 	clear_bit(NFS_LSEG_ROC, &lseg->pls_flags);
401 	clear_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
402 	if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags))
403 		pnfs_lseg_dec_and_remove_zero(lseg, free_me);
404 	if (test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
405 		pnfs_lseg_dec_and_remove_zero(lseg, free_me);
406 }
407 
408 /*
409  * Update the seqid of a layout stateid after receiving
410  * NFS4ERR_OLD_STATEID
411  */
412 bool nfs4_layout_refresh_old_stateid(nfs4_stateid *dst,
413 		struct pnfs_layout_range *dst_range,
414 		struct inode *inode)
415 {
416 	struct pnfs_layout_hdr *lo;
417 	struct pnfs_layout_range range = {
418 		.iomode = IOMODE_ANY,
419 		.offset = 0,
420 		.length = NFS4_MAX_UINT64,
421 	};
422 	bool ret = false;
423 	LIST_HEAD(head);
424 	int err;
425 
426 	spin_lock(&inode->i_lock);
427 	lo = NFS_I(inode)->layout;
428 	if (lo &&  pnfs_layout_is_valid(lo) &&
429 	    nfs4_stateid_match_other(dst, &lo->plh_stateid)) {
430 		/* Is our call using the most recent seqid? If so, bump it */
431 		if (!nfs4_stateid_is_newer(&lo->plh_stateid, dst)) {
432 			nfs4_stateid_seqid_inc(dst);
433 			ret = true;
434 			goto out;
435 		}
436 		/* Try to update the seqid to the most recent */
437 		err = pnfs_mark_matching_lsegs_return(lo, &head, &range, 0);
438 		if (err != -EBUSY) {
439 			dst->seqid = lo->plh_stateid.seqid;
440 			*dst_range = range;
441 			ret = true;
442 		}
443 	}
444 out:
445 	spin_unlock(&inode->i_lock);
446 	pnfs_free_lseg_list(&head);
447 	return ret;
448 }
449 
450 /*
451  * Mark a pnfs_layout_hdr and all associated layout segments as invalid
452  *
453  * In order to continue using the pnfs_layout_hdr, a full recovery
454  * is required.
455  * Note that caller must hold inode->i_lock.
456  */
457 int
458 pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
459 		struct list_head *lseg_list)
460 {
461 	struct pnfs_layout_range range = {
462 		.iomode = IOMODE_ANY,
463 		.offset = 0,
464 		.length = NFS4_MAX_UINT64,
465 	};
466 	struct pnfs_layout_segment *lseg, *next;
467 
468 	set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
469 	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
470 		pnfs_clear_lseg_state(lseg, lseg_list);
471 	pnfs_clear_layoutreturn_info(lo);
472 	pnfs_free_returned_lsegs(lo, lseg_list, &range, 0);
473 	set_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags);
474 	if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags) &&
475 	    !test_and_set_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags))
476 		pnfs_clear_layoutreturn_waitbit(lo);
477 	return !list_empty(&lo->plh_segs);
478 }
479 
480 static int pnfs_mark_layout_stateid_return(struct pnfs_layout_hdr *lo,
481 					   struct list_head *lseg_list,
482 					   enum pnfs_iomode iomode, u32 seq)
483 {
484 	struct pnfs_layout_range range = {
485 		.iomode = iomode,
486 		.length = NFS4_MAX_UINT64,
487 	};
488 
489 	return pnfs_mark_matching_lsegs_return(lo, lseg_list, &range, seq);
490 }
491 
492 static int
493 pnfs_iomode_to_fail_bit(u32 iomode)
494 {
495 	return iomode == IOMODE_RW ?
496 		NFS_LAYOUT_RW_FAILED : NFS_LAYOUT_RO_FAILED;
497 }
498 
499 static void
500 pnfs_layout_set_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
501 {
502 	lo->plh_retry_timestamp = jiffies;
503 	if (!test_and_set_bit(fail_bit, &lo->plh_flags))
504 		refcount_inc(&lo->plh_refcount);
505 }
506 
507 static void
508 pnfs_layout_clear_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
509 {
510 	if (test_and_clear_bit(fail_bit, &lo->plh_flags))
511 		refcount_dec(&lo->plh_refcount);
512 }
513 
514 static void
515 pnfs_layout_io_set_failed(struct pnfs_layout_hdr *lo, u32 iomode)
516 {
517 	struct inode *inode = lo->plh_inode;
518 	struct pnfs_layout_range range = {
519 		.iomode = iomode,
520 		.offset = 0,
521 		.length = NFS4_MAX_UINT64,
522 	};
523 	LIST_HEAD(head);
524 
525 	spin_lock(&inode->i_lock);
526 	pnfs_layout_set_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
527 	pnfs_mark_matching_lsegs_return(lo, &head, &range, 0);
528 	spin_unlock(&inode->i_lock);
529 	pnfs_free_lseg_list(&head);
530 	dprintk("%s Setting layout IOMODE_%s fail bit\n", __func__,
531 			iomode == IOMODE_RW ?  "RW" : "READ");
532 }
533 
534 static bool
535 pnfs_layout_io_test_failed(struct pnfs_layout_hdr *lo, u32 iomode)
536 {
537 	unsigned long start, end;
538 	int fail_bit = pnfs_iomode_to_fail_bit(iomode);
539 
540 	if (test_bit(fail_bit, &lo->plh_flags) == 0)
541 		return false;
542 	end = jiffies;
543 	start = end - PNFS_LAYOUTGET_RETRY_TIMEOUT;
544 	if (!time_in_range(lo->plh_retry_timestamp, start, end)) {
545 		/* It is time to retry the failed layoutgets */
546 		pnfs_layout_clear_fail_bit(lo, fail_bit);
547 		return false;
548 	}
549 	return true;
550 }
551 
552 static void
553 pnfs_init_lseg(struct pnfs_layout_hdr *lo, struct pnfs_layout_segment *lseg,
554 		const struct pnfs_layout_range *range,
555 		const nfs4_stateid *stateid)
556 {
557 	INIT_LIST_HEAD(&lseg->pls_list);
558 	INIT_LIST_HEAD(&lseg->pls_lc_list);
559 	INIT_LIST_HEAD(&lseg->pls_commits);
560 	refcount_set(&lseg->pls_refcount, 1);
561 	set_bit(NFS_LSEG_VALID, &lseg->pls_flags);
562 	lseg->pls_layout = lo;
563 	lseg->pls_range = *range;
564 	lseg->pls_seq = be32_to_cpu(stateid->seqid);
565 }
566 
567 static void pnfs_free_lseg(struct pnfs_layout_segment *lseg)
568 {
569 	if (lseg != NULL) {
570 		struct inode *inode = lseg->pls_layout->plh_inode;
571 		NFS_SERVER(inode)->pnfs_curr_ld->free_lseg(lseg);
572 	}
573 }
574 
575 static void
576 pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo,
577 		struct pnfs_layout_segment *lseg)
578 {
579 	WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
580 	list_del_init(&lseg->pls_list);
581 	/* Matched by pnfs_get_layout_hdr in pnfs_layout_insert_lseg */
582 	refcount_dec(&lo->plh_refcount);
583 	if (test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
584 		return;
585 	if (list_empty(&lo->plh_segs) &&
586 	    !test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags) &&
587 	    !test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
588 		if (atomic_read(&lo->plh_outstanding) == 0)
589 			set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
590 		clear_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
591 	}
592 }
593 
594 static bool
595 pnfs_cache_lseg_for_layoutreturn(struct pnfs_layout_hdr *lo,
596 		struct pnfs_layout_segment *lseg)
597 {
598 	if (test_and_clear_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags) &&
599 	    pnfs_layout_is_valid(lo)) {
600 		pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
601 		list_move_tail(&lseg->pls_list, &lo->plh_return_segs);
602 		return true;
603 	}
604 	return false;
605 }
606 
607 void
608 pnfs_put_lseg(struct pnfs_layout_segment *lseg)
609 {
610 	struct pnfs_layout_hdr *lo;
611 	struct inode *inode;
612 
613 	if (!lseg)
614 		return;
615 
616 	dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
617 		refcount_read(&lseg->pls_refcount),
618 		test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
619 
620 	lo = lseg->pls_layout;
621 	inode = lo->plh_inode;
622 
623 	if (refcount_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
624 		pnfs_get_layout_hdr(lo);
625 		pnfs_layout_remove_lseg(lo, lseg);
626 		if (pnfs_cache_lseg_for_layoutreturn(lo, lseg))
627 			lseg = NULL;
628 		spin_unlock(&inode->i_lock);
629 		pnfs_free_lseg(lseg);
630 		pnfs_put_layout_hdr(lo);
631 	}
632 }
633 EXPORT_SYMBOL_GPL(pnfs_put_lseg);
634 
635 /*
636  * is l2 fully contained in l1?
637  *   start1                             end1
638  *   [----------------------------------)
639  *           start2           end2
640  *           [----------------)
641  */
642 static bool
643 pnfs_lseg_range_contained(const struct pnfs_layout_range *l1,
644 		 const struct pnfs_layout_range *l2)
645 {
646 	u64 start1 = l1->offset;
647 	u64 end1 = pnfs_end_offset(start1, l1->length);
648 	u64 start2 = l2->offset;
649 	u64 end2 = pnfs_end_offset(start2, l2->length);
650 
651 	return (start1 <= start2) && (end1 >= end2);
652 }
653 
654 static bool pnfs_lseg_dec_and_remove_zero(struct pnfs_layout_segment *lseg,
655 		struct list_head *tmp_list)
656 {
657 	if (!refcount_dec_and_test(&lseg->pls_refcount))
658 		return false;
659 	pnfs_layout_remove_lseg(lseg->pls_layout, lseg);
660 	list_add(&lseg->pls_list, tmp_list);
661 	return true;
662 }
663 
664 /* Returns 1 if lseg is removed from list, 0 otherwise */
665 static int mark_lseg_invalid(struct pnfs_layout_segment *lseg,
666 			     struct list_head *tmp_list)
667 {
668 	int rv = 0;
669 
670 	if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
671 		/* Remove the reference keeping the lseg in the
672 		 * list.  It will now be removed when all
673 		 * outstanding io is finished.
674 		 */
675 		dprintk("%s: lseg %p ref %d\n", __func__, lseg,
676 			refcount_read(&lseg->pls_refcount));
677 		if (pnfs_lseg_dec_and_remove_zero(lseg, tmp_list))
678 			rv = 1;
679 	}
680 	return rv;
681 }
682 
683 static bool
684 pnfs_should_free_range(const struct pnfs_layout_range *lseg_range,
685 		 const struct pnfs_layout_range *recall_range)
686 {
687 	return (recall_range->iomode == IOMODE_ANY ||
688 		lseg_range->iomode == recall_range->iomode) &&
689 	       pnfs_lseg_range_intersecting(lseg_range, recall_range);
690 }
691 
692 static bool
693 pnfs_match_lseg_recall(const struct pnfs_layout_segment *lseg,
694 		const struct pnfs_layout_range *recall_range,
695 		u32 seq)
696 {
697 	if (seq != 0 && pnfs_seqid_is_newer(lseg->pls_seq, seq))
698 		return false;
699 	if (recall_range == NULL)
700 		return true;
701 	return pnfs_should_free_range(&lseg->pls_range, recall_range);
702 }
703 
704 /**
705  * pnfs_mark_matching_lsegs_invalid - tear down lsegs or mark them for later
706  * @lo: layout header containing the lsegs
707  * @tmp_list: list head where doomed lsegs should go
708  * @recall_range: optional recall range argument to match (may be NULL)
709  * @seq: only invalidate lsegs obtained prior to this sequence (may be 0)
710  *
711  * Walk the list of lsegs in the layout header, and tear down any that should
712  * be destroyed. If "recall_range" is specified then the segment must match
713  * that range. If "seq" is non-zero, then only match segments that were handed
714  * out at or before that sequence.
715  *
716  * Returns number of matching invalid lsegs remaining in list after scanning
717  * it and purging them.
718  */
719 int
720 pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
721 			    struct list_head *tmp_list,
722 			    const struct pnfs_layout_range *recall_range,
723 			    u32 seq)
724 {
725 	struct pnfs_layout_segment *lseg, *next;
726 	struct nfs_server *server = NFS_SERVER(lo->plh_inode);
727 	int remaining = 0;
728 
729 	dprintk("%s:Begin lo %p\n", __func__, lo);
730 
731 	if (list_empty(&lo->plh_segs))
732 		return 0;
733 	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
734 		if (pnfs_match_lseg_recall(lseg, recall_range, seq)) {
735 			dprintk("%s: freeing lseg %p iomode %d seq %u "
736 				"offset %llu length %llu\n", __func__,
737 				lseg, lseg->pls_range.iomode, lseg->pls_seq,
738 				lseg->pls_range.offset, lseg->pls_range.length);
739 			if (mark_lseg_invalid(lseg, tmp_list))
740 				continue;
741 			remaining++;
742 			pnfs_lseg_cancel_io(server, lseg);
743 		}
744 	dprintk("%s:Return %i\n", __func__, remaining);
745 	return remaining;
746 }
747 
748 static void
749 pnfs_free_returned_lsegs(struct pnfs_layout_hdr *lo,
750 		struct list_head *free_me,
751 		const struct pnfs_layout_range *range,
752 		u32 seq)
753 {
754 	struct pnfs_layout_segment *lseg, *next;
755 
756 	list_for_each_entry_safe(lseg, next, &lo->plh_return_segs, pls_list) {
757 		if (pnfs_match_lseg_recall(lseg, range, seq))
758 			list_move_tail(&lseg->pls_list, free_me);
759 	}
760 }
761 
762 /* note free_me must contain lsegs from a single layout_hdr */
763 void
764 pnfs_free_lseg_list(struct list_head *free_me)
765 {
766 	struct pnfs_layout_segment *lseg, *tmp;
767 
768 	if (list_empty(free_me))
769 		return;
770 
771 	list_for_each_entry_safe(lseg, tmp, free_me, pls_list) {
772 		list_del(&lseg->pls_list);
773 		pnfs_free_lseg(lseg);
774 	}
775 }
776 
777 static struct pnfs_layout_hdr *__pnfs_destroy_layout(struct nfs_inode *nfsi)
778 {
779 	struct pnfs_layout_hdr *lo;
780 	LIST_HEAD(tmp_list);
781 
782 	spin_lock(&nfsi->vfs_inode.i_lock);
783 	lo = nfsi->layout;
784 	if (lo) {
785 		pnfs_get_layout_hdr(lo);
786 		pnfs_mark_layout_stateid_invalid(lo, &tmp_list);
787 		pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RO_FAILED);
788 		pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RW_FAILED);
789 		spin_unlock(&nfsi->vfs_inode.i_lock);
790 		pnfs_free_lseg_list(&tmp_list);
791 		nfs_commit_inode(&nfsi->vfs_inode, 0);
792 		pnfs_put_layout_hdr(lo);
793 	} else
794 		spin_unlock(&nfsi->vfs_inode.i_lock);
795 	return lo;
796 }
797 
798 void pnfs_destroy_layout(struct nfs_inode *nfsi)
799 {
800 	__pnfs_destroy_layout(nfsi);
801 }
802 EXPORT_SYMBOL_GPL(pnfs_destroy_layout);
803 
804 static bool pnfs_layout_removed(struct nfs_inode *nfsi,
805 				struct pnfs_layout_hdr *lo)
806 {
807 	bool ret;
808 
809 	spin_lock(&nfsi->vfs_inode.i_lock);
810 	ret = nfsi->layout != lo;
811 	spin_unlock(&nfsi->vfs_inode.i_lock);
812 	return ret;
813 }
814 
815 void pnfs_destroy_layout_final(struct nfs_inode *nfsi)
816 {
817 	struct pnfs_layout_hdr *lo = __pnfs_destroy_layout(nfsi);
818 
819 	if (lo)
820 		wait_var_event(lo, pnfs_layout_removed(nfsi, lo));
821 }
822 
823 static bool
824 pnfs_layout_add_bulk_destroy_list(struct inode *inode,
825 		struct list_head *layout_list)
826 {
827 	struct pnfs_layout_hdr *lo;
828 	bool ret = false;
829 
830 	spin_lock(&inode->i_lock);
831 	lo = NFS_I(inode)->layout;
832 	if (lo != NULL && list_empty(&lo->plh_bulk_destroy)) {
833 		pnfs_get_layout_hdr(lo);
834 		list_add(&lo->plh_bulk_destroy, layout_list);
835 		ret = true;
836 	}
837 	spin_unlock(&inode->i_lock);
838 	return ret;
839 }
840 
841 /* Caller must hold rcu_read_lock and clp->cl_lock */
842 static int
843 pnfs_layout_bulk_destroy_byserver_locked(struct nfs_client *clp,
844 		struct nfs_server *server,
845 		struct list_head *layout_list)
846 	__must_hold(&clp->cl_lock)
847 	__must_hold(RCU)
848 {
849 	struct pnfs_layout_hdr *lo, *next;
850 	struct inode *inode;
851 
852 	list_for_each_entry_safe(lo, next, &server->layouts, plh_layouts) {
853 		if (test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags) ||
854 		    test_bit(NFS_LAYOUT_INODE_FREEING, &lo->plh_flags) ||
855 		    !list_empty(&lo->plh_bulk_destroy))
856 			continue;
857 		/* If the sb is being destroyed, just bail */
858 		if (!nfs_sb_active(server->super))
859 			break;
860 		inode = pnfs_grab_inode_layout_hdr(lo);
861 		if (inode != NULL) {
862 			if (pnfs_layout_add_bulk_destroy_list(inode,
863 						layout_list))
864 				continue;
865 			rcu_read_unlock();
866 			spin_unlock(&clp->cl_lock);
867 			iput(inode);
868 		} else {
869 			rcu_read_unlock();
870 			spin_unlock(&clp->cl_lock);
871 		}
872 		nfs_sb_deactive(server->super);
873 		spin_lock(&clp->cl_lock);
874 		rcu_read_lock();
875 		return -EAGAIN;
876 	}
877 	return 0;
878 }
879 
880 static int
881 pnfs_layout_free_bulk_destroy_list(struct list_head *layout_list,
882 				   enum pnfs_layout_destroy_mode mode)
883 {
884 	struct pnfs_layout_hdr *lo;
885 	struct inode *inode;
886 	LIST_HEAD(lseg_list);
887 	int ret = 0;
888 
889 	while (!list_empty(layout_list)) {
890 		lo = list_entry(layout_list->next, struct pnfs_layout_hdr,
891 				plh_bulk_destroy);
892 		dprintk("%s freeing layout for inode %lu\n", __func__,
893 			lo->plh_inode->i_ino);
894 		inode = lo->plh_inode;
895 
896 		pnfs_layoutcommit_inode(inode, false);
897 
898 		spin_lock(&inode->i_lock);
899 		list_del_init(&lo->plh_bulk_destroy);
900 		if (mode == PNFS_LAYOUT_FILE_BULK_RETURN) {
901 			pnfs_mark_layout_stateid_return(lo, &lseg_list,
902 							IOMODE_ANY, 0);
903 		} else if (pnfs_mark_layout_stateid_invalid(lo, &lseg_list)) {
904 			if (mode == PNFS_LAYOUT_BULK_RETURN)
905 				set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
906 			ret = -EAGAIN;
907 		}
908 		spin_unlock(&inode->i_lock);
909 		pnfs_free_lseg_list(&lseg_list);
910 		/* Free all lsegs that are attached to commit buckets */
911 		nfs_commit_inode(inode, 0);
912 		pnfs_put_layout_hdr(lo);
913 		nfs_iput_and_deactive(inode);
914 	}
915 	return ret;
916 }
917 
918 int pnfs_layout_destroy_byfsid(struct nfs_client *clp, struct nfs_fsid *fsid,
919 			       enum pnfs_layout_destroy_mode mode)
920 {
921 	struct nfs_server *server;
922 	LIST_HEAD(layout_list);
923 
924 	spin_lock(&clp->cl_lock);
925 	rcu_read_lock();
926 restart:
927 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
928 		if (memcmp(&server->fsid, fsid, sizeof(*fsid)) != 0)
929 			continue;
930 		if (pnfs_layout_bulk_destroy_byserver_locked(clp,
931 				server,
932 				&layout_list) != 0)
933 			goto restart;
934 	}
935 	rcu_read_unlock();
936 	spin_unlock(&clp->cl_lock);
937 
938 	return pnfs_layout_free_bulk_destroy_list(&layout_list, mode);
939 }
940 
941 static void pnfs_layout_build_destroy_list_byclient(struct nfs_client *clp,
942 						    struct list_head *list)
943 {
944 	struct nfs_server *server;
945 
946 	spin_lock(&clp->cl_lock);
947 	rcu_read_lock();
948 restart:
949 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
950 		if (pnfs_layout_bulk_destroy_byserver_locked(clp, server,
951 							     list) != 0)
952 			goto restart;
953 	}
954 	rcu_read_unlock();
955 	spin_unlock(&clp->cl_lock);
956 }
957 
958 static int pnfs_layout_do_destroy_byclid(struct nfs_client *clp,
959 					 struct list_head *list,
960 					 enum pnfs_layout_destroy_mode mode)
961 {
962 	pnfs_layout_build_destroy_list_byclient(clp, list);
963 	return pnfs_layout_free_bulk_destroy_list(list, mode);
964 }
965 
966 int pnfs_layout_destroy_byclid(struct nfs_client *clp,
967 			       enum pnfs_layout_destroy_mode mode)
968 {
969 	LIST_HEAD(layout_list);
970 
971 	return pnfs_layout_do_destroy_byclid(clp, &layout_list, mode);
972 }
973 
974 /*
975  * Called by the state manager to remove all layouts established under an
976  * expired lease.
977  */
978 void
979 pnfs_destroy_all_layouts(struct nfs_client *clp)
980 {
981 	nfs4_deviceid_mark_client_invalid(clp);
982 	nfs4_deviceid_purge_client(clp);
983 
984 	pnfs_layout_destroy_byclid(clp, PNFS_LAYOUT_INVALIDATE);
985 }
986 
987 static void pnfs_layout_build_recover_list_byclient(struct nfs_client *clp,
988 						    struct list_head *list)
989 {
990 	struct nfs_server *server;
991 
992 	spin_lock(&clp->cl_lock);
993 	rcu_read_lock();
994 restart:
995 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
996 		if (!(server->caps & NFS_CAP_REBOOT_LAYOUTRETURN))
997 			continue;
998 		if (pnfs_layout_bulk_destroy_byserver_locked(clp, server,
999 							     list) != 0)
1000 			goto restart;
1001 	}
1002 	rcu_read_unlock();
1003 	spin_unlock(&clp->cl_lock);
1004 }
1005 
1006 static int pnfs_layout_bulk_list_reboot(struct list_head *list)
1007 {
1008 	struct pnfs_layout_hdr *lo;
1009 	struct nfs_server *server;
1010 	int ret;
1011 
1012 	list_for_each_entry(lo, list, plh_bulk_destroy) {
1013 		server = NFS_SERVER(lo->plh_inode);
1014 		ret = pnfs_layout_return_on_reboot(lo);
1015 		switch (ret) {
1016 		case 0:
1017 			continue;
1018 		case -NFS4ERR_BAD_STATEID:
1019 			server->caps &= ~NFS_CAP_REBOOT_LAYOUTRETURN;
1020 			break;
1021 		case -NFS4ERR_NO_GRACE:
1022 			break;
1023 		default:
1024 			goto err;
1025 		}
1026 		break;
1027 	}
1028 	return 0;
1029 err:
1030 	return ret;
1031 }
1032 
1033 int pnfs_layout_handle_reboot(struct nfs_client *clp)
1034 {
1035 	LIST_HEAD(list);
1036 	int ret = 0, ret2;
1037 
1038 	pnfs_layout_build_recover_list_byclient(clp, &list);
1039 	if (!list_empty(&list))
1040 		ret = pnfs_layout_bulk_list_reboot(&list);
1041 	ret2 = pnfs_layout_do_destroy_byclid(clp, &list,
1042 					     PNFS_LAYOUT_INVALIDATE);
1043 	if (!ret)
1044 		ret = ret2;
1045 	return (ret == 0) ?  0 : -EAGAIN;
1046 }
1047 
1048 static void
1049 pnfs_set_layout_cred(struct pnfs_layout_hdr *lo, const struct cred *cred)
1050 {
1051 	const struct cred *old;
1052 
1053 	if (cred && cred_fscmp(lo->plh_lc_cred, cred) != 0) {
1054 		old = xchg(&lo->plh_lc_cred, get_cred(cred));
1055 		put_cred(old);
1056 	}
1057 }
1058 
1059 /* update lo->plh_stateid with new if is more recent */
1060 void
1061 pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
1062 			const struct cred *cred, bool update_barrier)
1063 {
1064 	u32 oldseq = be32_to_cpu(lo->plh_stateid.seqid);
1065 	u32 newseq = be32_to_cpu(new->seqid);
1066 
1067 	if (!pnfs_layout_is_valid(lo)) {
1068 		pnfs_set_layout_cred(lo, cred);
1069 		nfs4_stateid_copy(&lo->plh_stateid, new);
1070 		lo->plh_barrier = newseq;
1071 		pnfs_clear_layoutreturn_info(lo);
1072 		clear_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
1073 		return;
1074 	}
1075 
1076 	if (pnfs_seqid_is_newer(newseq, oldseq))
1077 		nfs4_stateid_copy(&lo->plh_stateid, new);
1078 
1079 	if (update_barrier) {
1080 		pnfs_barrier_update(lo, newseq);
1081 		return;
1082 	}
1083 	/*
1084 	 * Because of wraparound, we want to keep the barrier
1085 	 * "close" to the current seqids. We really only want to
1086 	 * get here from a layoutget call.
1087 	 */
1088 	if (atomic_read(&lo->plh_outstanding) == 1)
1089 		 pnfs_barrier_update(lo, be32_to_cpu(lo->plh_stateid.seqid));
1090 }
1091 
1092 static bool
1093 pnfs_layout_stateid_blocked(const struct pnfs_layout_hdr *lo,
1094 		const nfs4_stateid *stateid)
1095 {
1096 	u32 seqid = be32_to_cpu(stateid->seqid);
1097 
1098 	return lo->plh_barrier && pnfs_seqid_is_newer(lo->plh_barrier, seqid);
1099 }
1100 
1101 /* lget is set to 1 if called from inside send_layoutget call chain */
1102 static bool
1103 pnfs_layoutgets_blocked(const struct pnfs_layout_hdr *lo)
1104 {
1105 	return lo->plh_block_lgets ||
1106 		test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
1107 }
1108 
1109 static struct nfs_server *
1110 pnfs_find_server(struct inode *inode, struct nfs_open_context *ctx)
1111 {
1112 	struct nfs_server *server;
1113 
1114 	if (inode) {
1115 		server = NFS_SERVER(inode);
1116 	} else {
1117 		struct dentry *parent_dir = dget_parent(ctx->dentry);
1118 		server = NFS_SERVER(parent_dir->d_inode);
1119 		dput(parent_dir);
1120 	}
1121 	return server;
1122 }
1123 
1124 static void nfs4_free_pages(struct page **pages, size_t size)
1125 {
1126 	int i;
1127 
1128 	if (!pages)
1129 		return;
1130 
1131 	for (i = 0; i < size; i++) {
1132 		if (!pages[i])
1133 			break;
1134 		__free_page(pages[i]);
1135 	}
1136 	kfree(pages);
1137 }
1138 
1139 static struct page **nfs4_alloc_pages(size_t size, gfp_t gfp_flags)
1140 {
1141 	struct page **pages;
1142 	int i;
1143 
1144 	pages = kmalloc_array(size, sizeof(struct page *), gfp_flags);
1145 	if (!pages) {
1146 		dprintk("%s: can't alloc array of %zu pages\n", __func__, size);
1147 		return NULL;
1148 	}
1149 
1150 	for (i = 0; i < size; i++) {
1151 		pages[i] = alloc_page(gfp_flags);
1152 		if (!pages[i]) {
1153 			dprintk("%s: failed to allocate page\n", __func__);
1154 			nfs4_free_pages(pages, i);
1155 			return NULL;
1156 		}
1157 	}
1158 
1159 	return pages;
1160 }
1161 
1162 static struct nfs4_layoutget *
1163 pnfs_alloc_init_layoutget_args(struct inode *ino,
1164 	   struct nfs_open_context *ctx,
1165 	   const nfs4_stateid *stateid,
1166 	   const struct pnfs_layout_range *range,
1167 	   gfp_t gfp_flags)
1168 {
1169 	struct nfs_server *server = pnfs_find_server(ino, ctx);
1170 	size_t max_reply_sz = server->pnfs_curr_ld->max_layoutget_response;
1171 	size_t max_pages = max_response_pages(server);
1172 	struct nfs4_layoutget *lgp;
1173 
1174 	dprintk("--> %s\n", __func__);
1175 
1176 	lgp = kzalloc(sizeof(*lgp), gfp_flags);
1177 	if (lgp == NULL)
1178 		return NULL;
1179 
1180 	if (max_reply_sz) {
1181 		size_t npages = (max_reply_sz + PAGE_SIZE - 1) >> PAGE_SHIFT;
1182 		if (npages < max_pages)
1183 			max_pages = npages;
1184 	}
1185 
1186 	lgp->args.layout.pages = nfs4_alloc_pages(max_pages, gfp_flags);
1187 	if (!lgp->args.layout.pages) {
1188 		kfree(lgp);
1189 		return NULL;
1190 	}
1191 	lgp->args.layout.pglen = max_pages * PAGE_SIZE;
1192 	lgp->res.layoutp = &lgp->args.layout;
1193 
1194 	/* Don't confuse uninitialised result and success */
1195 	lgp->res.status = -NFS4ERR_DELAY;
1196 
1197 	lgp->args.minlength = PAGE_SIZE;
1198 	if (lgp->args.minlength > range->length)
1199 		lgp->args.minlength = range->length;
1200 	if (ino) {
1201 		loff_t i_size = i_size_read(ino);
1202 
1203 		if (range->iomode == IOMODE_READ) {
1204 			if (range->offset >= i_size)
1205 				lgp->args.minlength = 0;
1206 			else if (i_size - range->offset < lgp->args.minlength)
1207 				lgp->args.minlength = i_size - range->offset;
1208 		}
1209 	}
1210 	lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
1211 	pnfs_copy_range(&lgp->args.range, range);
1212 	lgp->args.type = server->pnfs_curr_ld->id;
1213 	lgp->args.inode = ino;
1214 	lgp->args.ctx = get_nfs_open_context(ctx);
1215 	nfs4_stateid_copy(&lgp->args.stateid, stateid);
1216 	lgp->gfp_flags = gfp_flags;
1217 	lgp->cred = ctx->cred;
1218 	return lgp;
1219 }
1220 
1221 void pnfs_layoutget_free(struct nfs4_layoutget *lgp)
1222 {
1223 	size_t max_pages = lgp->args.layout.pglen / PAGE_SIZE;
1224 
1225 	nfs4_free_pages(lgp->args.layout.pages, max_pages);
1226 	pnfs_put_layout_hdr(lgp->lo);
1227 	put_nfs_open_context(lgp->args.ctx);
1228 	kfree(lgp);
1229 }
1230 
1231 static void pnfs_clear_layoutcommit(struct inode *inode,
1232 		struct list_head *head)
1233 {
1234 	struct nfs_inode *nfsi = NFS_I(inode);
1235 	struct pnfs_layout_segment *lseg, *tmp;
1236 
1237 	if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
1238 		return;
1239 	list_for_each_entry_safe(lseg, tmp, &nfsi->layout->plh_segs, pls_list) {
1240 		if (!test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
1241 			continue;
1242 		pnfs_lseg_dec_and_remove_zero(lseg, head);
1243 	}
1244 }
1245 
1246 static void
1247 pnfs_layoutreturn_retry_later_locked(struct pnfs_layout_hdr *lo,
1248 				     const nfs4_stateid *arg_stateid,
1249 				     const struct pnfs_layout_range *range)
1250 {
1251 	const struct pnfs_layout_segment *lseg;
1252 	u32 seq = be32_to_cpu(arg_stateid->seqid);
1253 
1254 	if (pnfs_layout_is_valid(lo) &&
1255 	    nfs4_stateid_match_other(&lo->plh_stateid, arg_stateid)) {
1256 		list_for_each_entry(lseg, &lo->plh_return_segs, pls_list) {
1257 			if (pnfs_seqid_is_newer(lseg->pls_seq, seq) ||
1258 			    !pnfs_should_free_range(&lseg->pls_range, range))
1259 				continue;
1260 			pnfs_set_plh_return_info(lo, range->iomode, seq);
1261 			break;
1262 		}
1263 	}
1264 }
1265 
1266 void pnfs_layoutreturn_retry_later(struct pnfs_layout_hdr *lo,
1267 				   const nfs4_stateid *arg_stateid,
1268 				   const struct pnfs_layout_range *range)
1269 {
1270 	struct inode *inode = lo->plh_inode;
1271 
1272 	spin_lock(&inode->i_lock);
1273 	pnfs_layoutreturn_retry_later_locked(lo, arg_stateid, range);
1274 	pnfs_clear_layoutreturn_waitbit(lo);
1275 	spin_unlock(&inode->i_lock);
1276 }
1277 
1278 void pnfs_layoutreturn_free_lsegs(struct pnfs_layout_hdr *lo,
1279 		const nfs4_stateid *arg_stateid,
1280 		const struct pnfs_layout_range *range,
1281 		const nfs4_stateid *stateid)
1282 {
1283 	struct inode *inode = lo->plh_inode;
1284 	LIST_HEAD(freeme);
1285 
1286 	spin_lock(&inode->i_lock);
1287 	if (!nfs4_stateid_match_other(&lo->plh_stateid, arg_stateid))
1288 		goto out_unlock;
1289 	if (stateid && pnfs_layout_is_valid(lo)) {
1290 		u32 seq = be32_to_cpu(arg_stateid->seqid);
1291 
1292 		pnfs_mark_matching_lsegs_invalid(lo, &freeme, range, seq);
1293 		pnfs_free_returned_lsegs(lo, &freeme, range, seq);
1294 		pnfs_set_layout_stateid(lo, stateid, NULL, true);
1295 	} else
1296 		pnfs_mark_layout_stateid_invalid(lo, &freeme);
1297 out_unlock:
1298 	pnfs_clear_layoutreturn_waitbit(lo);
1299 	spin_unlock(&inode->i_lock);
1300 	pnfs_free_lseg_list(&freeme);
1301 
1302 }
1303 
1304 static bool
1305 pnfs_prepare_layoutreturn(struct pnfs_layout_hdr *lo,
1306 		nfs4_stateid *stateid,
1307 		const struct cred **cred,
1308 		enum pnfs_iomode *iomode)
1309 {
1310 	/* Serialise LAYOUTGET/LAYOUTRETURN */
1311 	if (atomic_read(&lo->plh_outstanding) != 0)
1312 		return false;
1313 	if (test_and_set_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags))
1314 		return false;
1315 	set_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);
1316 	pnfs_get_layout_hdr(lo);
1317 	nfs4_stateid_copy(stateid, &lo->plh_stateid);
1318 	*cred = get_cred(lo->plh_lc_cred);
1319 	if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags)) {
1320 		if (lo->plh_return_seq != 0)
1321 			stateid->seqid = cpu_to_be32(lo->plh_return_seq);
1322 		if (iomode != NULL)
1323 			*iomode = lo->plh_return_iomode;
1324 		pnfs_clear_layoutreturn_info(lo);
1325 	} else if (iomode != NULL)
1326 		*iomode = IOMODE_ANY;
1327 	pnfs_barrier_update(lo, be32_to_cpu(stateid->seqid));
1328 	return true;
1329 }
1330 
1331 static void
1332 pnfs_init_layoutreturn_args(struct nfs4_layoutreturn_args *args,
1333 		struct pnfs_layout_hdr *lo,
1334 		const nfs4_stateid *stateid,
1335 		enum pnfs_iomode iomode)
1336 {
1337 	struct inode *inode = lo->plh_inode;
1338 
1339 	args->layout_type = NFS_SERVER(inode)->pnfs_curr_ld->id;
1340 	args->inode = inode;
1341 	args->range.iomode = iomode;
1342 	args->range.offset = 0;
1343 	args->range.length = NFS4_MAX_UINT64;
1344 	args->layout = lo;
1345 	nfs4_stateid_copy(&args->stateid, stateid);
1346 }
1347 
1348 static int
1349 pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo,
1350 		       const nfs4_stateid *stateid,
1351 		       const struct cred **pcred,
1352 		       enum pnfs_iomode iomode,
1353 		       unsigned int flags)
1354 {
1355 	struct inode *ino = lo->plh_inode;
1356 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
1357 	struct nfs4_layoutreturn *lrp;
1358 	const struct cred *cred = *pcred;
1359 	int status = 0;
1360 
1361 	*pcred = NULL;
1362 	lrp = kzalloc(sizeof(*lrp), nfs_io_gfp_mask());
1363 	if (unlikely(lrp == NULL)) {
1364 		status = -ENOMEM;
1365 		spin_lock(&ino->i_lock);
1366 		pnfs_clear_layoutreturn_waitbit(lo);
1367 		spin_unlock(&ino->i_lock);
1368 		put_cred(cred);
1369 		pnfs_put_layout_hdr(lo);
1370 		goto out;
1371 	}
1372 
1373 	pnfs_init_layoutreturn_args(&lrp->args, lo, stateid, iomode);
1374 	lrp->args.ld_private = &lrp->ld_private;
1375 	lrp->clp = NFS_SERVER(ino)->nfs_client;
1376 	lrp->cred = cred;
1377 	if (ld->prepare_layoutreturn)
1378 		ld->prepare_layoutreturn(&lrp->args);
1379 
1380 	status = nfs4_proc_layoutreturn(lrp, flags);
1381 out:
1382 	dprintk("<-- %s status: %d\n", __func__, status);
1383 	return status;
1384 }
1385 
1386 /* Return true if layoutreturn is needed */
1387 static bool
1388 pnfs_layout_need_return(struct pnfs_layout_hdr *lo)
1389 {
1390 	if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
1391 		return false;
1392 	return pnfs_mark_layout_stateid_return(lo, &lo->plh_return_segs,
1393 					       lo->plh_return_iomode,
1394 					       lo->plh_return_seq) != EBUSY;
1395 }
1396 
1397 static void pnfs_layoutreturn_before_put_layout_hdr(struct pnfs_layout_hdr *lo)
1398 {
1399 	struct inode *inode= lo->plh_inode;
1400 
1401 	if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
1402 		return;
1403 	spin_lock(&inode->i_lock);
1404 	if (pnfs_layout_need_return(lo)) {
1405 		const struct cred *cred;
1406 		nfs4_stateid stateid;
1407 		enum pnfs_iomode iomode;
1408 		bool send;
1409 
1410 		send = pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode);
1411 		spin_unlock(&inode->i_lock);
1412 		if (send) {
1413 			/* Send an async layoutreturn so we dont deadlock */
1414 			pnfs_send_layoutreturn(lo, &stateid, &cred, iomode,
1415 					       PNFS_FL_LAYOUTRETURN_ASYNC);
1416 		}
1417 	} else
1418 		spin_unlock(&inode->i_lock);
1419 }
1420 
1421 /*
1422  * Initiates a LAYOUTRETURN(FILE), and removes the pnfs_layout_hdr
1423  * when the layout segment list is empty.
1424  *
1425  * Note that a pnfs_layout_hdr can exist with an empty layout segment
1426  * list when LAYOUTGET has failed, or when LAYOUTGET succeeded, but the
1427  * deviceid is marked invalid.
1428  */
1429 int
1430 _pnfs_return_layout(struct inode *ino)
1431 {
1432 	struct pnfs_layout_hdr *lo = NULL;
1433 	struct nfs_inode *nfsi = NFS_I(ino);
1434 	struct pnfs_layout_range range = {
1435 		.iomode		= IOMODE_ANY,
1436 		.offset		= 0,
1437 		.length		= NFS4_MAX_UINT64,
1438 	};
1439 	LIST_HEAD(tmp_list);
1440 	const struct cred *cred;
1441 	nfs4_stateid stateid;
1442 	int status = 0;
1443 	bool send, valid_layout;
1444 
1445 	dprintk("NFS: %s for inode %lu\n", __func__, ino->i_ino);
1446 
1447 	spin_lock(&ino->i_lock);
1448 	lo = nfsi->layout;
1449 	if (!lo) {
1450 		spin_unlock(&ino->i_lock);
1451 		dprintk("NFS: %s no layout to return\n", __func__);
1452 		goto out;
1453 	}
1454 	/* Reference matched in nfs4_layoutreturn_release */
1455 	pnfs_get_layout_hdr(lo);
1456 	/* Is there an outstanding layoutreturn ? */
1457 	if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
1458 		spin_unlock(&ino->i_lock);
1459 		if (wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
1460 					TASK_UNINTERRUPTIBLE))
1461 			goto out_put_layout_hdr;
1462 		spin_lock(&ino->i_lock);
1463 	}
1464 	valid_layout = pnfs_layout_is_valid(lo);
1465 	pnfs_clear_layoutcommit(ino, &tmp_list);
1466 	pnfs_mark_matching_lsegs_return(lo, &tmp_list, &range, 0);
1467 
1468 	if (NFS_SERVER(ino)->pnfs_curr_ld->return_range)
1469 		NFS_SERVER(ino)->pnfs_curr_ld->return_range(lo, &range);
1470 
1471 	/* Don't send a LAYOUTRETURN if list was initially empty */
1472 	if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags) ||
1473 			!valid_layout) {
1474 		spin_unlock(&ino->i_lock);
1475 		dprintk("NFS: %s no layout segments to return\n", __func__);
1476 		goto out_wait_layoutreturn;
1477 	}
1478 
1479 	send = pnfs_prepare_layoutreturn(lo, &stateid, &cred, NULL);
1480 	spin_unlock(&ino->i_lock);
1481 	if (send)
1482 		status = pnfs_send_layoutreturn(lo, &stateid, &cred, IOMODE_ANY,
1483 						0);
1484 out_wait_layoutreturn:
1485 	wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN, TASK_UNINTERRUPTIBLE);
1486 out_put_layout_hdr:
1487 	pnfs_free_lseg_list(&tmp_list);
1488 	pnfs_put_layout_hdr(lo);
1489 out:
1490 	dprintk("<-- %s status: %d\n", __func__, status);
1491 	return status;
1492 }
1493 
1494 int
1495 pnfs_commit_and_return_layout(struct inode *inode)
1496 {
1497 	struct pnfs_layout_hdr *lo;
1498 	int ret;
1499 
1500 	spin_lock(&inode->i_lock);
1501 	lo = NFS_I(inode)->layout;
1502 	if (lo == NULL) {
1503 		spin_unlock(&inode->i_lock);
1504 		return 0;
1505 	}
1506 	pnfs_get_layout_hdr(lo);
1507 	/* Block new layoutgets and read/write to ds */
1508 	lo->plh_block_lgets++;
1509 	spin_unlock(&inode->i_lock);
1510 	filemap_fdatawait(inode->i_mapping);
1511 	ret = pnfs_layoutcommit_inode(inode, true);
1512 	if (ret == 0)
1513 		ret = _pnfs_return_layout(inode);
1514 	spin_lock(&inode->i_lock);
1515 	lo->plh_block_lgets--;
1516 	spin_unlock(&inode->i_lock);
1517 	pnfs_put_layout_hdr(lo);
1518 	return ret;
1519 }
1520 
1521 static int pnfs_layout_return_on_reboot(struct pnfs_layout_hdr *lo)
1522 {
1523 	struct inode *inode = lo->plh_inode;
1524 	const struct cred *cred;
1525 
1526 	spin_lock(&inode->i_lock);
1527 	if (!pnfs_layout_is_valid(lo)) {
1528 		spin_unlock(&inode->i_lock);
1529 		return 0;
1530 	}
1531 	cred = get_cred(lo->plh_lc_cred);
1532 	pnfs_get_layout_hdr(lo);
1533 	spin_unlock(&inode->i_lock);
1534 
1535 	return pnfs_send_layoutreturn(lo, &zero_stateid, &cred, IOMODE_ANY,
1536 				      PNFS_FL_LAYOUTRETURN_PRIVILEGED);
1537 }
1538 
1539 bool pnfs_roc(struct inode *ino,
1540 		struct nfs4_layoutreturn_args *args,
1541 		struct nfs4_layoutreturn_res *res,
1542 		const struct cred *cred)
1543 {
1544 	struct nfs_inode *nfsi = NFS_I(ino);
1545 	struct nfs_open_context *ctx;
1546 	struct nfs4_state *state;
1547 	struct pnfs_layout_hdr *lo;
1548 	struct pnfs_layout_segment *lseg, *next;
1549 	const struct cred *lc_cred;
1550 	nfs4_stateid stateid;
1551 	enum pnfs_iomode iomode = 0;
1552 	bool layoutreturn = false, roc = false;
1553 	bool skip_read = false;
1554 
1555 	if (!nfs_have_layout(ino))
1556 		return false;
1557 retry:
1558 	rcu_read_lock();
1559 	spin_lock(&ino->i_lock);
1560 	lo = nfsi->layout;
1561 	if (!lo || !pnfs_layout_is_valid(lo) ||
1562 	    test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1563 		lo = NULL;
1564 		goto out_noroc;
1565 	}
1566 	pnfs_get_layout_hdr(lo);
1567 	if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
1568 		spin_unlock(&ino->i_lock);
1569 		rcu_read_unlock();
1570 		wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
1571 				TASK_UNINTERRUPTIBLE);
1572 		pnfs_put_layout_hdr(lo);
1573 		goto retry;
1574 	}
1575 
1576 	/* no roc if we hold a delegation */
1577 	if (nfs4_check_delegation(ino, FMODE_READ)) {
1578 		if (nfs4_check_delegation(ino, FMODE_WRITE))
1579 			goto out_noroc;
1580 		skip_read = true;
1581 	}
1582 
1583 	list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
1584 		state = ctx->state;
1585 		if (state == NULL)
1586 			continue;
1587 		/* Don't return layout if there is open file state */
1588 		if (state->state & FMODE_WRITE)
1589 			goto out_noroc;
1590 		if (state->state & FMODE_READ)
1591 			skip_read = true;
1592 	}
1593 
1594 
1595 	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list) {
1596 		if (skip_read && lseg->pls_range.iomode == IOMODE_READ)
1597 			continue;
1598 		/* If we are sending layoutreturn, invalidate all valid lsegs */
1599 		if (!test_and_clear_bit(NFS_LSEG_ROC, &lseg->pls_flags))
1600 			continue;
1601 		/*
1602 		 * Note: mark lseg for return so pnfs_layout_remove_lseg
1603 		 * doesn't invalidate the layout for us.
1604 		 */
1605 		set_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
1606 		if (!mark_lseg_invalid(lseg, &lo->plh_return_segs))
1607 			continue;
1608 		pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
1609 	}
1610 
1611 	if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
1612 		goto out_noroc;
1613 
1614 	/* ROC in two conditions:
1615 	 * 1. there are ROC lsegs
1616 	 * 2. we don't send layoutreturn
1617 	 */
1618 	/* lo ref dropped in pnfs_roc_release() */
1619 	layoutreturn = pnfs_prepare_layoutreturn(lo, &stateid, &lc_cred, &iomode);
1620 	/* If the creds don't match, we can't compound the layoutreturn */
1621 	if (!layoutreturn || cred_fscmp(cred, lc_cred) != 0)
1622 		goto out_noroc;
1623 
1624 	roc = layoutreturn;
1625 	pnfs_init_layoutreturn_args(args, lo, &stateid, iomode);
1626 	res->lrs_present = 0;
1627 	layoutreturn = false;
1628 	put_cred(lc_cred);
1629 
1630 out_noroc:
1631 	spin_unlock(&ino->i_lock);
1632 	rcu_read_unlock();
1633 	pnfs_layoutcommit_inode(ino, true);
1634 	if (roc) {
1635 		struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
1636 		if (ld->prepare_layoutreturn)
1637 			ld->prepare_layoutreturn(args);
1638 		pnfs_put_layout_hdr(lo);
1639 		return true;
1640 	}
1641 	if (layoutreturn)
1642 		pnfs_send_layoutreturn(lo, &stateid, &lc_cred, iomode, 0);
1643 	pnfs_put_layout_hdr(lo);
1644 	return false;
1645 }
1646 
1647 int pnfs_roc_done(struct rpc_task *task, struct nfs4_layoutreturn_args **argpp,
1648 		  struct nfs4_layoutreturn_res **respp, int *ret)
1649 {
1650 	struct nfs4_layoutreturn_args *arg = *argpp;
1651 	int retval = -EAGAIN;
1652 
1653 	if (!arg)
1654 		return 0;
1655 	/* Handle Layoutreturn errors */
1656 	switch (*ret) {
1657 	case 0:
1658 		retval = 0;
1659 		break;
1660 	case -NFS4ERR_NOMATCHING_LAYOUT:
1661 		/* Was there an RPC level error? If not, retry */
1662 		if (task->tk_rpc_status == 0)
1663 			break;
1664 		/* If the call was not sent, let caller handle it */
1665 		if (!RPC_WAS_SENT(task))
1666 			return 0;
1667 		/*
1668 		 * Otherwise, assume the call succeeded and
1669 		 * that we need to release the layout
1670 		 */
1671 		*ret = 0;
1672 		(*respp)->lrs_present = 0;
1673 		retval = 0;
1674 		break;
1675 	case -NFS4ERR_DELAY:
1676 		/* Let the caller handle the retry */
1677 		*ret = -NFS4ERR_NOMATCHING_LAYOUT;
1678 		return 0;
1679 	case -NFS4ERR_OLD_STATEID:
1680 		if (!nfs4_layout_refresh_old_stateid(&arg->stateid,
1681 						     &arg->range, arg->inode))
1682 			break;
1683 		*ret = -NFS4ERR_NOMATCHING_LAYOUT;
1684 		return -EAGAIN;
1685 	}
1686 	*argpp = NULL;
1687 	*respp = NULL;
1688 	return retval;
1689 }
1690 
1691 void pnfs_roc_release(struct nfs4_layoutreturn_args *args,
1692 		      struct nfs4_layoutreturn_res *res, int ret)
1693 {
1694 	struct pnfs_layout_hdr *lo = args->layout;
1695 	struct inode *inode = args->inode;
1696 	const nfs4_stateid *res_stateid = NULL;
1697 	struct nfs4_xdr_opaque_data *ld_private = args->ld_private;
1698 
1699 	switch (ret) {
1700 	case -NFS4ERR_BADSESSION:
1701 	case -NFS4ERR_DEADSESSION:
1702 	case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
1703 	case -NFS4ERR_NOMATCHING_LAYOUT:
1704 		spin_lock(&inode->i_lock);
1705 		pnfs_layoutreturn_retry_later_locked(lo, &args->stateid,
1706 						     &args->range);
1707 		pnfs_clear_layoutreturn_waitbit(lo);
1708 		spin_unlock(&inode->i_lock);
1709 		break;
1710 	case 0:
1711 		if (res->lrs_present)
1712 			res_stateid = &res->stateid;
1713 		fallthrough;
1714 	default:
1715 		pnfs_layoutreturn_free_lsegs(lo, &args->stateid, &args->range,
1716 					     res_stateid);
1717 	}
1718 	trace_nfs4_layoutreturn_on_close(args->inode, &args->stateid, ret);
1719 	if (ld_private && ld_private->ops && ld_private->ops->free)
1720 		ld_private->ops->free(ld_private);
1721 	pnfs_put_layout_hdr(lo);
1722 }
1723 
1724 bool pnfs_wait_on_layoutreturn(struct inode *ino, struct rpc_task *task)
1725 {
1726 	struct nfs_inode *nfsi = NFS_I(ino);
1727         struct pnfs_layout_hdr *lo;
1728         bool sleep = false;
1729 
1730 	/* we might not have grabbed lo reference. so need to check under
1731 	 * i_lock */
1732         spin_lock(&ino->i_lock);
1733         lo = nfsi->layout;
1734         if (lo && test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
1735                 rpc_sleep_on(&NFS_SERVER(ino)->roc_rpcwaitq, task, NULL);
1736                 sleep = true;
1737 	}
1738         spin_unlock(&ino->i_lock);
1739         return sleep;
1740 }
1741 
1742 /*
1743  * Compare two layout segments for sorting into layout cache.
1744  * We want to preferentially return RW over RO layouts, so ensure those
1745  * are seen first.
1746  */
1747 static s64
1748 pnfs_lseg_range_cmp(const struct pnfs_layout_range *l1,
1749 	   const struct pnfs_layout_range *l2)
1750 {
1751 	s64 d;
1752 
1753 	/* high offset > low offset */
1754 	d = l1->offset - l2->offset;
1755 	if (d)
1756 		return d;
1757 
1758 	/* short length > long length */
1759 	d = l2->length - l1->length;
1760 	if (d)
1761 		return d;
1762 
1763 	/* read > read/write */
1764 	return (int)(l1->iomode == IOMODE_READ) - (int)(l2->iomode == IOMODE_READ);
1765 }
1766 
1767 static bool
1768 pnfs_lseg_range_is_after(const struct pnfs_layout_range *l1,
1769 		const struct pnfs_layout_range *l2)
1770 {
1771 	return pnfs_lseg_range_cmp(l1, l2) > 0;
1772 }
1773 
1774 static bool
1775 pnfs_lseg_no_merge(struct pnfs_layout_segment *lseg,
1776 		struct pnfs_layout_segment *old)
1777 {
1778 	return false;
1779 }
1780 
1781 void
1782 pnfs_generic_layout_insert_lseg(struct pnfs_layout_hdr *lo,
1783 		   struct pnfs_layout_segment *lseg,
1784 		   bool (*is_after)(const struct pnfs_layout_range *,
1785 			   const struct pnfs_layout_range *),
1786 		   bool (*do_merge)(struct pnfs_layout_segment *,
1787 			   struct pnfs_layout_segment *),
1788 		   struct list_head *free_me)
1789 {
1790 	struct pnfs_layout_segment *lp, *tmp;
1791 
1792 	dprintk("%s:Begin\n", __func__);
1793 
1794 	list_for_each_entry_safe(lp, tmp, &lo->plh_segs, pls_list) {
1795 		if (test_bit(NFS_LSEG_VALID, &lp->pls_flags) == 0)
1796 			continue;
1797 		if (do_merge(lseg, lp)) {
1798 			mark_lseg_invalid(lp, free_me);
1799 			continue;
1800 		}
1801 		if (is_after(&lseg->pls_range, &lp->pls_range))
1802 			continue;
1803 		list_add_tail(&lseg->pls_list, &lp->pls_list);
1804 		dprintk("%s: inserted lseg %p "
1805 			"iomode %d offset %llu length %llu before "
1806 			"lp %p iomode %d offset %llu length %llu\n",
1807 			__func__, lseg, lseg->pls_range.iomode,
1808 			lseg->pls_range.offset, lseg->pls_range.length,
1809 			lp, lp->pls_range.iomode, lp->pls_range.offset,
1810 			lp->pls_range.length);
1811 		goto out;
1812 	}
1813 	list_add_tail(&lseg->pls_list, &lo->plh_segs);
1814 	dprintk("%s: inserted lseg %p "
1815 		"iomode %d offset %llu length %llu at tail\n",
1816 		__func__, lseg, lseg->pls_range.iomode,
1817 		lseg->pls_range.offset, lseg->pls_range.length);
1818 out:
1819 	pnfs_get_layout_hdr(lo);
1820 
1821 	dprintk("%s:Return\n", __func__);
1822 }
1823 EXPORT_SYMBOL_GPL(pnfs_generic_layout_insert_lseg);
1824 
1825 static void
1826 pnfs_layout_insert_lseg(struct pnfs_layout_hdr *lo,
1827 		   struct pnfs_layout_segment *lseg,
1828 		   struct list_head *free_me)
1829 {
1830 	struct inode *inode = lo->plh_inode;
1831 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
1832 
1833 	if (ld->add_lseg != NULL)
1834 		ld->add_lseg(lo, lseg, free_me);
1835 	else
1836 		pnfs_generic_layout_insert_lseg(lo, lseg,
1837 				pnfs_lseg_range_is_after,
1838 				pnfs_lseg_no_merge,
1839 				free_me);
1840 }
1841 
1842 static struct pnfs_layout_hdr *
1843 alloc_init_layout_hdr(struct inode *ino,
1844 		      struct nfs_open_context *ctx,
1845 		      gfp_t gfp_flags)
1846 {
1847 	struct pnfs_layout_hdr *lo;
1848 
1849 	lo = pnfs_alloc_layout_hdr(ino, gfp_flags);
1850 	if (!lo)
1851 		return NULL;
1852 	refcount_set(&lo->plh_refcount, 1);
1853 	INIT_LIST_HEAD(&lo->plh_layouts);
1854 	INIT_LIST_HEAD(&lo->plh_segs);
1855 	INIT_LIST_HEAD(&lo->plh_return_segs);
1856 	INIT_LIST_HEAD(&lo->plh_bulk_destroy);
1857 	lo->plh_inode = ino;
1858 	lo->plh_lc_cred = get_cred(ctx->cred);
1859 	lo->plh_flags |= 1 << NFS_LAYOUT_INVALID_STID;
1860 	return lo;
1861 }
1862 
1863 static struct pnfs_layout_hdr *
1864 pnfs_find_alloc_layout(struct inode *ino,
1865 		       struct nfs_open_context *ctx,
1866 		       gfp_t gfp_flags)
1867 	__releases(&ino->i_lock)
1868 	__acquires(&ino->i_lock)
1869 {
1870 	struct nfs_inode *nfsi = NFS_I(ino);
1871 	struct pnfs_layout_hdr *new = NULL;
1872 
1873 	dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);
1874 
1875 	if (nfsi->layout != NULL)
1876 		goto out_existing;
1877 	spin_unlock(&ino->i_lock);
1878 	new = alloc_init_layout_hdr(ino, ctx, gfp_flags);
1879 	spin_lock(&ino->i_lock);
1880 
1881 	if (likely(nfsi->layout == NULL)) {	/* Won the race? */
1882 		nfsi->layout = new;
1883 		return new;
1884 	} else if (new != NULL)
1885 		pnfs_free_layout_hdr(new);
1886 out_existing:
1887 	pnfs_get_layout_hdr(nfsi->layout);
1888 	return nfsi->layout;
1889 }
1890 
1891 /*
1892  * iomode matching rules:
1893  * iomode	lseg	strict match
1894  *                      iomode
1895  * -----	-----	------ -----
1896  * ANY		READ	N/A    true
1897  * ANY		RW	N/A    true
1898  * RW		READ	N/A    false
1899  * RW		RW	N/A    true
1900  * READ		READ	N/A    true
1901  * READ		RW	true   false
1902  * READ		RW	false  true
1903  */
1904 static bool
1905 pnfs_lseg_range_match(const struct pnfs_layout_range *ls_range,
1906 		 const struct pnfs_layout_range *range,
1907 		 bool strict_iomode)
1908 {
1909 	struct pnfs_layout_range range1;
1910 
1911 	if ((range->iomode == IOMODE_RW &&
1912 	     ls_range->iomode != IOMODE_RW) ||
1913 	    (range->iomode != ls_range->iomode &&
1914 	     strict_iomode) ||
1915 	    !pnfs_lseg_range_intersecting(ls_range, range))
1916 		return false;
1917 
1918 	/* range1 covers only the first byte in the range */
1919 	range1 = *range;
1920 	range1.length = 1;
1921 	return pnfs_lseg_range_contained(ls_range, &range1);
1922 }
1923 
1924 /*
1925  * lookup range in layout
1926  */
1927 static struct pnfs_layout_segment *
1928 pnfs_find_lseg(struct pnfs_layout_hdr *lo,
1929 		struct pnfs_layout_range *range,
1930 		bool strict_iomode)
1931 {
1932 	struct pnfs_layout_segment *lseg, *ret = NULL;
1933 
1934 	dprintk("%s:Begin\n", __func__);
1935 
1936 	list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
1937 		if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
1938 		    pnfs_lseg_range_match(&lseg->pls_range, range,
1939 					  strict_iomode)) {
1940 			ret = pnfs_get_lseg(lseg);
1941 			break;
1942 		}
1943 	}
1944 
1945 	dprintk("%s:Return lseg %p ref %d\n",
1946 		__func__, ret, ret ? refcount_read(&ret->pls_refcount) : 0);
1947 	return ret;
1948 }
1949 
1950 /*
1951  * Use mdsthreshold hints set at each OPEN to determine if I/O should go
1952  * to the MDS or over pNFS
1953  *
1954  * The nfs_inode read_io and write_io fields are cumulative counters reset
1955  * when there are no layout segments. Note that in pnfs_update_layout iomode
1956  * is set to IOMODE_READ for a READ request, and set to IOMODE_RW for a
1957  * WRITE request.
1958  *
1959  * A return of true means use MDS I/O.
1960  *
1961  * From rfc 5661:
1962  * If a file's size is smaller than the file size threshold, data accesses
1963  * SHOULD be sent to the metadata server.  If an I/O request has a length that
1964  * is below the I/O size threshold, the I/O SHOULD be sent to the metadata
1965  * server.  If both file size and I/O size are provided, the client SHOULD
1966  * reach or exceed  both thresholds before sending its read or write
1967  * requests to the data server.
1968  */
1969 static bool pnfs_within_mdsthreshold(struct nfs_open_context *ctx,
1970 				     struct inode *ino, int iomode)
1971 {
1972 	struct nfs4_threshold *t = ctx->mdsthreshold;
1973 	struct nfs_inode *nfsi = NFS_I(ino);
1974 	loff_t fsize = i_size_read(ino);
1975 	bool size = false, size_set = false, io = false, io_set = false, ret = false;
1976 
1977 	if (t == NULL)
1978 		return ret;
1979 
1980 	dprintk("%s bm=0x%x rd_sz=%llu wr_sz=%llu rd_io=%llu wr_io=%llu\n",
1981 		__func__, t->bm, t->rd_sz, t->wr_sz, t->rd_io_sz, t->wr_io_sz);
1982 
1983 	switch (iomode) {
1984 	case IOMODE_READ:
1985 		if (t->bm & THRESHOLD_RD) {
1986 			dprintk("%s fsize %llu\n", __func__, fsize);
1987 			size_set = true;
1988 			if (fsize < t->rd_sz)
1989 				size = true;
1990 		}
1991 		if (t->bm & THRESHOLD_RD_IO) {
1992 			dprintk("%s nfsi->read_io %llu\n", __func__,
1993 				nfsi->read_io);
1994 			io_set = true;
1995 			if (nfsi->read_io < t->rd_io_sz)
1996 				io = true;
1997 		}
1998 		break;
1999 	case IOMODE_RW:
2000 		if (t->bm & THRESHOLD_WR) {
2001 			dprintk("%s fsize %llu\n", __func__, fsize);
2002 			size_set = true;
2003 			if (fsize < t->wr_sz)
2004 				size = true;
2005 		}
2006 		if (t->bm & THRESHOLD_WR_IO) {
2007 			dprintk("%s nfsi->write_io %llu\n", __func__,
2008 				nfsi->write_io);
2009 			io_set = true;
2010 			if (nfsi->write_io < t->wr_io_sz)
2011 				io = true;
2012 		}
2013 		break;
2014 	}
2015 	if (size_set && io_set) {
2016 		if (size && io)
2017 			ret = true;
2018 	} else if (size || io)
2019 		ret = true;
2020 
2021 	dprintk("<-- %s size %d io %d ret %d\n", __func__, size, io, ret);
2022 	return ret;
2023 }
2024 
2025 static int pnfs_prepare_to_retry_layoutget(struct pnfs_layout_hdr *lo)
2026 {
2027 	/*
2028 	 * send layoutcommit as it can hold up layoutreturn due to lseg
2029 	 * reference
2030 	 */
2031 	pnfs_layoutcommit_inode(lo->plh_inode, false);
2032 	return wait_on_bit_action(&lo->plh_flags, NFS_LAYOUT_RETURN,
2033 				   nfs_wait_bit_killable,
2034 				   TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
2035 }
2036 
2037 static void nfs_layoutget_begin(struct pnfs_layout_hdr *lo)
2038 {
2039 	atomic_inc(&lo->plh_outstanding);
2040 }
2041 
2042 static void nfs_layoutget_end(struct pnfs_layout_hdr *lo)
2043 {
2044 	if (atomic_dec_and_test(&lo->plh_outstanding) &&
2045 	    test_and_clear_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags))
2046 		wake_up_bit(&lo->plh_flags, NFS_LAYOUT_DRAIN);
2047 }
2048 
2049 static bool pnfs_is_first_layoutget(struct pnfs_layout_hdr *lo)
2050 {
2051 	return test_bit(NFS_LAYOUT_FIRST_LAYOUTGET, &lo->plh_flags);
2052 }
2053 
2054 static void pnfs_clear_first_layoutget(struct pnfs_layout_hdr *lo)
2055 {
2056 	unsigned long *bitlock = &lo->plh_flags;
2057 
2058 	clear_bit_unlock(NFS_LAYOUT_FIRST_LAYOUTGET, bitlock);
2059 	smp_mb__after_atomic();
2060 	wake_up_bit(bitlock, NFS_LAYOUT_FIRST_LAYOUTGET);
2061 }
2062 
2063 static void _add_to_server_list(struct pnfs_layout_hdr *lo,
2064 				struct nfs_server *server)
2065 {
2066 	if (!test_and_set_bit(NFS_LAYOUT_HASHED, &lo->plh_flags)) {
2067 		struct nfs_client *clp = server->nfs_client;
2068 
2069 		/* The lo must be on the clp list if there is any
2070 		 * chance of a CB_LAYOUTRECALL(FILE) coming in.
2071 		 */
2072 		spin_lock(&clp->cl_lock);
2073 		list_add_tail_rcu(&lo->plh_layouts, &server->layouts);
2074 		spin_unlock(&clp->cl_lock);
2075 	}
2076 }
2077 
2078 /*
2079  * Layout segment is retreived from the server if not cached.
2080  * The appropriate layout segment is referenced and returned to the caller.
2081  */
2082 struct pnfs_layout_segment *
2083 pnfs_update_layout(struct inode *ino,
2084 		   struct nfs_open_context *ctx,
2085 		   loff_t pos,
2086 		   u64 count,
2087 		   enum pnfs_iomode iomode,
2088 		   bool strict_iomode,
2089 		   gfp_t gfp_flags)
2090 {
2091 	struct pnfs_layout_range arg = {
2092 		.iomode = iomode,
2093 		.offset = pos,
2094 		.length = count,
2095 	};
2096 	unsigned pg_offset;
2097 	struct nfs_server *server = NFS_SERVER(ino);
2098 	struct nfs_client *clp = server->nfs_client;
2099 	struct pnfs_layout_hdr *lo = NULL;
2100 	struct pnfs_layout_segment *lseg = NULL;
2101 	struct nfs4_layoutget *lgp;
2102 	nfs4_stateid stateid;
2103 	struct nfs4_exception exception = {
2104 		.inode = ino,
2105 	};
2106 	unsigned long giveup = jiffies + (clp->cl_lease_time << 1);
2107 	bool first;
2108 
2109 	if (!pnfs_enabled_sb(NFS_SERVER(ino))) {
2110 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2111 				 PNFS_UPDATE_LAYOUT_NO_PNFS);
2112 		goto out;
2113 	}
2114 
2115 	if (pnfs_within_mdsthreshold(ctx, ino, iomode)) {
2116 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2117 				 PNFS_UPDATE_LAYOUT_MDSTHRESH);
2118 		goto out;
2119 	}
2120 
2121 lookup_again:
2122 	if (!nfs4_valid_open_stateid(ctx->state)) {
2123 		trace_pnfs_update_layout(ino, pos, count,
2124 					 iomode, lo, lseg,
2125 					 PNFS_UPDATE_LAYOUT_INVALID_OPEN);
2126 		lseg = ERR_PTR(-EIO);
2127 		goto out;
2128 	}
2129 
2130 	lseg = ERR_PTR(nfs4_client_recover_expired_lease(clp));
2131 	if (IS_ERR(lseg))
2132 		goto out;
2133 	first = false;
2134 	spin_lock(&ino->i_lock);
2135 	lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
2136 	if (lo == NULL) {
2137 		spin_unlock(&ino->i_lock);
2138 		lseg = ERR_PTR(-ENOMEM);
2139 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2140 				 PNFS_UPDATE_LAYOUT_NOMEM);
2141 		goto out;
2142 	}
2143 
2144 	/* Do we even need to bother with this? */
2145 	if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
2146 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2147 				 PNFS_UPDATE_LAYOUT_BULK_RECALL);
2148 		dprintk("%s matches recall, use MDS\n", __func__);
2149 		goto out_unlock;
2150 	}
2151 
2152 	/* if LAYOUTGET already failed once we don't try again */
2153 	if (pnfs_layout_io_test_failed(lo, iomode)) {
2154 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2155 				 PNFS_UPDATE_LAYOUT_IO_TEST_FAIL);
2156 		goto out_unlock;
2157 	}
2158 
2159 	/*
2160 	 * If the layout segment list is empty, but there are outstanding
2161 	 * layoutget calls, then they might be subject to a layoutrecall.
2162 	 */
2163 	if (test_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags) &&
2164 	    atomic_read(&lo->plh_outstanding) != 0) {
2165 		spin_unlock(&ino->i_lock);
2166 		lseg = ERR_PTR(wait_on_bit(&lo->plh_flags, NFS_LAYOUT_DRAIN,
2167 					   TASK_KILLABLE));
2168 		if (IS_ERR(lseg))
2169 			goto out_put_layout_hdr;
2170 		pnfs_put_layout_hdr(lo);
2171 		goto lookup_again;
2172 	}
2173 
2174 	/*
2175 	 * Because we free lsegs when sending LAYOUTRETURN, we need to wait
2176 	 * for LAYOUTRETURN.
2177 	 */
2178 	if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
2179 		spin_unlock(&ino->i_lock);
2180 		dprintk("%s wait for layoutreturn\n", __func__);
2181 		lseg = ERR_PTR(pnfs_prepare_to_retry_layoutget(lo));
2182 		if (!IS_ERR(lseg)) {
2183 			pnfs_put_layout_hdr(lo);
2184 			dprintk("%s retrying\n", __func__);
2185 			trace_pnfs_update_layout(ino, pos, count, iomode, lo,
2186 						 lseg,
2187 						 PNFS_UPDATE_LAYOUT_RETRY);
2188 			goto lookup_again;
2189 		}
2190 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2191 					 PNFS_UPDATE_LAYOUT_RETURN);
2192 		goto out_put_layout_hdr;
2193 	}
2194 
2195 	lseg = pnfs_find_lseg(lo, &arg, strict_iomode);
2196 	if (lseg) {
2197 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2198 				PNFS_UPDATE_LAYOUT_FOUND_CACHED);
2199 		goto out_unlock;
2200 	}
2201 
2202 	/*
2203 	 * Choose a stateid for the LAYOUTGET. If we don't have a layout
2204 	 * stateid, or it has been invalidated, then we must use the open
2205 	 * stateid.
2206 	 */
2207 	if (test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags)) {
2208 		int status;
2209 
2210 		/*
2211 		 * The first layoutget for the file. Need to serialize per
2212 		 * RFC 5661 Errata 3208.
2213 		 */
2214 		if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET,
2215 				     &lo->plh_flags)) {
2216 			spin_unlock(&ino->i_lock);
2217 			lseg = ERR_PTR(wait_on_bit(&lo->plh_flags,
2218 						NFS_LAYOUT_FIRST_LAYOUTGET,
2219 						TASK_KILLABLE));
2220 			if (IS_ERR(lseg))
2221 				goto out_put_layout_hdr;
2222 			pnfs_put_layout_hdr(lo);
2223 			dprintk("%s retrying\n", __func__);
2224 			goto lookup_again;
2225 		}
2226 
2227 		spin_unlock(&ino->i_lock);
2228 		first = true;
2229 		status = nfs4_select_rw_stateid(ctx->state,
2230 					iomode == IOMODE_RW ? FMODE_WRITE : FMODE_READ,
2231 					NULL, &stateid, NULL);
2232 		if (status != 0) {
2233 			lseg = ERR_PTR(status);
2234 			trace_pnfs_update_layout(ino, pos, count,
2235 					iomode, lo, lseg,
2236 					PNFS_UPDATE_LAYOUT_INVALID_OPEN);
2237 			nfs4_schedule_stateid_recovery(server, ctx->state);
2238 			pnfs_clear_first_layoutget(lo);
2239 			pnfs_put_layout_hdr(lo);
2240 			goto lookup_again;
2241 		}
2242 		spin_lock(&ino->i_lock);
2243 	} else {
2244 		nfs4_stateid_copy(&stateid, &lo->plh_stateid);
2245 	}
2246 
2247 	if (pnfs_layoutgets_blocked(lo)) {
2248 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2249 				PNFS_UPDATE_LAYOUT_BLOCKED);
2250 		goto out_unlock;
2251 	}
2252 	nfs_layoutget_begin(lo);
2253 	spin_unlock(&ino->i_lock);
2254 
2255 	_add_to_server_list(lo, server);
2256 
2257 	pg_offset = arg.offset & ~PAGE_MASK;
2258 	if (pg_offset) {
2259 		arg.offset -= pg_offset;
2260 		arg.length += pg_offset;
2261 	}
2262 	if (arg.length != NFS4_MAX_UINT64)
2263 		arg.length = PAGE_ALIGN(arg.length);
2264 
2265 	lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &stateid, &arg, gfp_flags);
2266 	if (!lgp) {
2267 		lseg = ERR_PTR(-ENOMEM);
2268 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, NULL,
2269 					 PNFS_UPDATE_LAYOUT_NOMEM);
2270 		nfs_layoutget_end(lo);
2271 		goto out_put_layout_hdr;
2272 	}
2273 
2274 	lgp->lo = lo;
2275 	pnfs_get_layout_hdr(lo);
2276 
2277 	lseg = nfs4_proc_layoutget(lgp, &exception);
2278 	trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2279 				 PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET);
2280 	nfs_layoutget_end(lo);
2281 	if (IS_ERR(lseg)) {
2282 		switch(PTR_ERR(lseg)) {
2283 		case -EBUSY:
2284 			if (time_after(jiffies, giveup))
2285 				lseg = NULL;
2286 			break;
2287 		case -ERECALLCONFLICT:
2288 		case -EAGAIN:
2289 			break;
2290 		case -ENODATA:
2291 			/* The server returned NFS4ERR_LAYOUTUNAVAILABLE */
2292 			pnfs_layout_set_fail_bit(
2293 				lo, pnfs_iomode_to_fail_bit(iomode));
2294 			lseg = NULL;
2295 			goto out_put_layout_hdr;
2296 		default:
2297 			if (!nfs_error_is_fatal(PTR_ERR(lseg))) {
2298 				pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
2299 				lseg = NULL;
2300 			}
2301 			goto out_put_layout_hdr;
2302 		}
2303 		if (lseg) {
2304 			if (!exception.retry)
2305 				goto out_put_layout_hdr;
2306 			if (first)
2307 				pnfs_clear_first_layoutget(lo);
2308 			trace_pnfs_update_layout(ino, pos, count,
2309 				iomode, lo, lseg, PNFS_UPDATE_LAYOUT_RETRY);
2310 			pnfs_put_layout_hdr(lo);
2311 			goto lookup_again;
2312 		}
2313 	} else {
2314 		pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
2315 	}
2316 
2317 out_put_layout_hdr:
2318 	if (first)
2319 		pnfs_clear_first_layoutget(lo);
2320 	trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2321 				 PNFS_UPDATE_LAYOUT_EXIT);
2322 	pnfs_put_layout_hdr(lo);
2323 out:
2324 	dprintk("%s: inode %s/%llu pNFS layout segment %s for "
2325 			"(%s, offset: %llu, length: %llu)\n",
2326 			__func__, ino->i_sb->s_id,
2327 			(unsigned long long)NFS_FILEID(ino),
2328 			IS_ERR_OR_NULL(lseg) ? "not found" : "found",
2329 			iomode==IOMODE_RW ?  "read/write" : "read-only",
2330 			(unsigned long long)pos,
2331 			(unsigned long long)count);
2332 	return lseg;
2333 out_unlock:
2334 	spin_unlock(&ino->i_lock);
2335 	goto out_put_layout_hdr;
2336 }
2337 EXPORT_SYMBOL_GPL(pnfs_update_layout);
2338 
2339 static bool
2340 pnfs_sanity_check_layout_range(struct pnfs_layout_range *range)
2341 {
2342 	switch (range->iomode) {
2343 	case IOMODE_READ:
2344 	case IOMODE_RW:
2345 		break;
2346 	default:
2347 		return false;
2348 	}
2349 	if (range->offset == NFS4_MAX_UINT64)
2350 		return false;
2351 	if (range->length == 0)
2352 		return false;
2353 	if (range->length != NFS4_MAX_UINT64 &&
2354 	    range->length > NFS4_MAX_UINT64 - range->offset)
2355 		return false;
2356 	return true;
2357 }
2358 
2359 static struct pnfs_layout_hdr *
2360 _pnfs_grab_empty_layout(struct inode *ino, struct nfs_open_context *ctx)
2361 {
2362 	struct pnfs_layout_hdr *lo;
2363 
2364 	spin_lock(&ino->i_lock);
2365 	lo = pnfs_find_alloc_layout(ino, ctx, nfs_io_gfp_mask());
2366 	if (!lo)
2367 		goto out_unlock;
2368 	if (!test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags))
2369 		goto out_unlock;
2370 	if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags))
2371 		goto out_unlock;
2372 	if (pnfs_layoutgets_blocked(lo))
2373 		goto out_unlock;
2374 	if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET, &lo->plh_flags))
2375 		goto out_unlock;
2376 	nfs_layoutget_begin(lo);
2377 	spin_unlock(&ino->i_lock);
2378 	_add_to_server_list(lo, NFS_SERVER(ino));
2379 	return lo;
2380 
2381 out_unlock:
2382 	spin_unlock(&ino->i_lock);
2383 	pnfs_put_layout_hdr(lo);
2384 	return NULL;
2385 }
2386 
2387 static void _lgopen_prepare_attached(struct nfs4_opendata *data,
2388 				     struct nfs_open_context *ctx)
2389 {
2390 	struct inode *ino = data->dentry->d_inode;
2391 	struct pnfs_layout_range rng = {
2392 		.iomode = (data->o_arg.fmode & FMODE_WRITE) ?
2393 			  IOMODE_RW: IOMODE_READ,
2394 		.offset = 0,
2395 		.length = NFS4_MAX_UINT64,
2396 	};
2397 	struct nfs4_layoutget *lgp;
2398 	struct pnfs_layout_hdr *lo;
2399 
2400 	/* Heuristic: don't send layoutget if we have cached data */
2401 	if (rng.iomode == IOMODE_READ &&
2402 	   (i_size_read(ino) == 0 || ino->i_mapping->nrpages != 0))
2403 		return;
2404 
2405 	lo = _pnfs_grab_empty_layout(ino, ctx);
2406 	if (!lo)
2407 		return;
2408 	lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &current_stateid, &rng,
2409 					     nfs_io_gfp_mask());
2410 	if (!lgp) {
2411 		pnfs_clear_first_layoutget(lo);
2412 		nfs_layoutget_end(lo);
2413 		pnfs_put_layout_hdr(lo);
2414 		return;
2415 	}
2416 	lgp->lo = lo;
2417 	data->lgp = lgp;
2418 	data->o_arg.lg_args = &lgp->args;
2419 	data->o_res.lg_res = &lgp->res;
2420 }
2421 
2422 static void _lgopen_prepare_floating(struct nfs4_opendata *data,
2423 				     struct nfs_open_context *ctx)
2424 {
2425 	struct inode *ino = data->dentry->d_inode;
2426 	struct pnfs_layout_range rng = {
2427 		.iomode = (data->o_arg.fmode & FMODE_WRITE) ?
2428 			  IOMODE_RW: IOMODE_READ,
2429 		.offset = 0,
2430 		.length = NFS4_MAX_UINT64,
2431 	};
2432 	struct nfs4_layoutget *lgp;
2433 
2434 	lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &current_stateid, &rng,
2435 					     nfs_io_gfp_mask());
2436 	if (!lgp)
2437 		return;
2438 	data->lgp = lgp;
2439 	data->o_arg.lg_args = &lgp->args;
2440 	data->o_res.lg_res = &lgp->res;
2441 }
2442 
2443 void pnfs_lgopen_prepare(struct nfs4_opendata *data,
2444 			 struct nfs_open_context *ctx)
2445 {
2446 	struct nfs_server *server = NFS_SERVER(data->dir->d_inode);
2447 
2448 	if (!(pnfs_enabled_sb(server) &&
2449 	      server->pnfs_curr_ld->flags & PNFS_LAYOUTGET_ON_OPEN))
2450 		return;
2451 	/* Could check on max_ops, but currently hardcoded high enough */
2452 	if (!nfs_server_capable(data->dir->d_inode, NFS_CAP_LGOPEN))
2453 		return;
2454 	if (data->lgp)
2455 		return;
2456 	if (data->state)
2457 		_lgopen_prepare_attached(data, ctx);
2458 	else
2459 		_lgopen_prepare_floating(data, ctx);
2460 }
2461 
2462 void pnfs_parse_lgopen(struct inode *ino, struct nfs4_layoutget *lgp,
2463 		       struct nfs_open_context *ctx)
2464 {
2465 	struct pnfs_layout_hdr *lo;
2466 	struct pnfs_layout_segment *lseg;
2467 	struct nfs_server *srv = NFS_SERVER(ino);
2468 	u32 iomode;
2469 
2470 	if (!lgp)
2471 		return;
2472 	dprintk("%s: entered with status %i\n", __func__, lgp->res.status);
2473 	if (lgp->res.status) {
2474 		switch (lgp->res.status) {
2475 		default:
2476 			break;
2477 		/*
2478 		 * Halt lgopen attempts if the server doesn't recognise
2479 		 * the "current stateid" value, the layout type, or the
2480 		 * layoutget operation as being valid.
2481 		 * Also if it complains about too many ops in the compound
2482 		 * or of the request/reply being too big.
2483 		 */
2484 		case -NFS4ERR_BAD_STATEID:
2485 		case -NFS4ERR_NOTSUPP:
2486 		case -NFS4ERR_REP_TOO_BIG:
2487 		case -NFS4ERR_REP_TOO_BIG_TO_CACHE:
2488 		case -NFS4ERR_REQ_TOO_BIG:
2489 		case -NFS4ERR_TOO_MANY_OPS:
2490 		case -NFS4ERR_UNKNOWN_LAYOUTTYPE:
2491 			srv->caps &= ~NFS_CAP_LGOPEN;
2492 		}
2493 		return;
2494 	}
2495 	if (!lgp->lo) {
2496 		lo = _pnfs_grab_empty_layout(ino, ctx);
2497 		if (!lo)
2498 			return;
2499 		lgp->lo = lo;
2500 	} else
2501 		lo = lgp->lo;
2502 
2503 	lseg = pnfs_layout_process(lgp);
2504 	if (!IS_ERR(lseg)) {
2505 		iomode = lgp->args.range.iomode;
2506 		pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
2507 		pnfs_put_lseg(lseg);
2508 	}
2509 }
2510 
2511 void nfs4_lgopen_release(struct nfs4_layoutget *lgp)
2512 {
2513 	if (lgp != NULL) {
2514 		if (lgp->lo) {
2515 			pnfs_clear_first_layoutget(lgp->lo);
2516 			nfs_layoutget_end(lgp->lo);
2517 		}
2518 		pnfs_layoutget_free(lgp);
2519 	}
2520 }
2521 
2522 struct pnfs_layout_segment *
2523 pnfs_layout_process(struct nfs4_layoutget *lgp)
2524 {
2525 	struct pnfs_layout_hdr *lo = lgp->lo;
2526 	struct nfs4_layoutget_res *res = &lgp->res;
2527 	struct pnfs_layout_segment *lseg;
2528 	struct inode *ino = lo->plh_inode;
2529 	LIST_HEAD(free_me);
2530 
2531 	if (!pnfs_sanity_check_layout_range(&res->range))
2532 		return ERR_PTR(-EINVAL);
2533 
2534 	/* Inject layout blob into I/O device driver */
2535 	lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res, lgp->gfp_flags);
2536 	if (IS_ERR_OR_NULL(lseg)) {
2537 		if (!lseg)
2538 			lseg = ERR_PTR(-ENOMEM);
2539 
2540 		dprintk("%s: Could not allocate layout: error %ld\n",
2541 		       __func__, PTR_ERR(lseg));
2542 		return lseg;
2543 	}
2544 
2545 	pnfs_init_lseg(lo, lseg, &res->range, &res->stateid);
2546 
2547 	spin_lock(&ino->i_lock);
2548 	if (pnfs_layoutgets_blocked(lo)) {
2549 		dprintk("%s forget reply due to state\n", __func__);
2550 		goto out_forget;
2551 	}
2552 
2553 	if (test_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags) &&
2554 	    !pnfs_is_first_layoutget(lo))
2555 		goto out_forget;
2556 
2557 	if (nfs4_stateid_match_other(&lo->plh_stateid, &res->stateid)) {
2558 		/* existing state ID, make sure the sequence number matches. */
2559 		if (pnfs_layout_stateid_blocked(lo, &res->stateid)) {
2560 			if (!pnfs_layout_is_valid(lo))
2561 				lo->plh_barrier = 0;
2562 			dprintk("%s forget reply due to sequence\n", __func__);
2563 			goto out_forget;
2564 		}
2565 		pnfs_set_layout_stateid(lo, &res->stateid, lgp->cred, false);
2566 	} else if (pnfs_layout_is_valid(lo)) {
2567 		/*
2568 		 * We got an entirely new state ID.  Mark all segments for the
2569 		 * inode invalid, and retry the layoutget
2570 		 */
2571 		struct pnfs_layout_range range = {
2572 			.iomode = IOMODE_ANY,
2573 			.length = NFS4_MAX_UINT64,
2574 		};
2575 		pnfs_mark_matching_lsegs_return(lo, &free_me, &range, 0);
2576 		goto out_forget;
2577 	} else {
2578 		/* We have a completely new layout */
2579 		pnfs_set_layout_stateid(lo, &res->stateid, lgp->cred, true);
2580 	}
2581 
2582 	pnfs_get_lseg(lseg);
2583 	pnfs_layout_insert_lseg(lo, lseg, &free_me);
2584 
2585 
2586 	if (res->return_on_close)
2587 		set_bit(NFS_LSEG_ROC, &lseg->pls_flags);
2588 
2589 	spin_unlock(&ino->i_lock);
2590 	pnfs_free_lseg_list(&free_me);
2591 	return lseg;
2592 
2593 out_forget:
2594 	spin_unlock(&ino->i_lock);
2595 	lseg->pls_layout = lo;
2596 	NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
2597 	return ERR_PTR(-EAGAIN);
2598 }
2599 
2600 /**
2601  * pnfs_mark_matching_lsegs_return - Free or return matching layout segments
2602  * @lo: pointer to layout header
2603  * @tmp_list: list header to be used with pnfs_free_lseg_list()
2604  * @return_range: describe layout segment ranges to be returned
2605  * @seq: stateid seqid to match
2606  *
2607  * This function is mainly intended for use by layoutrecall. It attempts
2608  * to free the layout segment immediately, or else to mark it for return
2609  * as soon as its reference count drops to zero.
2610  *
2611  * Returns
2612  * - 0: a layoutreturn needs to be scheduled.
2613  * - EBUSY: there are layout segment that are still in use.
2614  * - ENOENT: there are no layout segments that need to be returned.
2615  */
2616 int
2617 pnfs_mark_matching_lsegs_return(struct pnfs_layout_hdr *lo,
2618 				struct list_head *tmp_list,
2619 				const struct pnfs_layout_range *return_range,
2620 				u32 seq)
2621 {
2622 	struct pnfs_layout_segment *lseg, *next;
2623 	struct nfs_server *server = NFS_SERVER(lo->plh_inode);
2624 	int remaining = 0;
2625 
2626 	dprintk("%s:Begin lo %p\n", __func__, lo);
2627 
2628 	assert_spin_locked(&lo->plh_inode->i_lock);
2629 
2630 	if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
2631 		tmp_list = &lo->plh_return_segs;
2632 
2633 	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
2634 		if (pnfs_match_lseg_recall(lseg, return_range, seq)) {
2635 			dprintk("%s: marking lseg %p iomode %d "
2636 				"offset %llu length %llu\n", __func__,
2637 				lseg, lseg->pls_range.iomode,
2638 				lseg->pls_range.offset,
2639 				lseg->pls_range.length);
2640 			if (test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
2641 				tmp_list = &lo->plh_return_segs;
2642 			if (mark_lseg_invalid(lseg, tmp_list))
2643 				continue;
2644 			remaining++;
2645 			set_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
2646 			pnfs_lseg_cancel_io(server, lseg);
2647 		}
2648 
2649 	if (remaining) {
2650 		pnfs_set_plh_return_info(lo, return_range->iomode, seq);
2651 		return -EBUSY;
2652 	}
2653 
2654 	if (!list_empty(&lo->plh_return_segs)) {
2655 		pnfs_set_plh_return_info(lo, return_range->iomode, seq);
2656 		return 0;
2657 	}
2658 
2659 	return -ENOENT;
2660 }
2661 
2662 static void
2663 pnfs_mark_layout_for_return(struct inode *inode,
2664 			    const struct pnfs_layout_range *range)
2665 {
2666 	struct pnfs_layout_hdr *lo;
2667 	bool return_now = false;
2668 
2669 	spin_lock(&inode->i_lock);
2670 	lo = NFS_I(inode)->layout;
2671 	if (!pnfs_layout_is_valid(lo)) {
2672 		spin_unlock(&inode->i_lock);
2673 		return;
2674 	}
2675 	pnfs_set_plh_return_info(lo, range->iomode, 0);
2676 	/*
2677 	 * mark all matching lsegs so that we are sure to have no live
2678 	 * segments at hand when sending layoutreturn. See pnfs_put_lseg()
2679 	 * for how it works.
2680 	 */
2681 	if (pnfs_mark_matching_lsegs_return(lo, &lo->plh_return_segs, range, 0) != -EBUSY) {
2682 		const struct cred *cred;
2683 		nfs4_stateid stateid;
2684 		enum pnfs_iomode iomode;
2685 
2686 		return_now = pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode);
2687 		spin_unlock(&inode->i_lock);
2688 		if (return_now)
2689 			pnfs_send_layoutreturn(lo, &stateid, &cred, iomode,
2690 					       PNFS_FL_LAYOUTRETURN_ASYNC);
2691 	} else {
2692 		spin_unlock(&inode->i_lock);
2693 		nfs_commit_inode(inode, 0);
2694 	}
2695 }
2696 
2697 void pnfs_error_mark_layout_for_return(struct inode *inode,
2698 				       struct pnfs_layout_segment *lseg)
2699 {
2700 	struct pnfs_layout_range range = {
2701 		.iomode = lseg->pls_range.iomode,
2702 		.offset = 0,
2703 		.length = NFS4_MAX_UINT64,
2704 	};
2705 
2706 	pnfs_mark_layout_for_return(inode, &range);
2707 }
2708 EXPORT_SYMBOL_GPL(pnfs_error_mark_layout_for_return);
2709 
2710 static bool
2711 pnfs_layout_can_be_returned(struct pnfs_layout_hdr *lo)
2712 {
2713 	return pnfs_layout_is_valid(lo) &&
2714 		!test_bit(NFS_LAYOUT_INODE_FREEING, &lo->plh_flags) &&
2715 		!test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);
2716 }
2717 
2718 static struct pnfs_layout_segment *
2719 pnfs_find_first_lseg(struct pnfs_layout_hdr *lo,
2720 		     const struct pnfs_layout_range *range,
2721 		     enum pnfs_iomode iomode)
2722 {
2723 	struct pnfs_layout_segment *lseg;
2724 
2725 	list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
2726 		if (!test_bit(NFS_LSEG_VALID, &lseg->pls_flags))
2727 			continue;
2728 		if (test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
2729 			continue;
2730 		if (lseg->pls_range.iomode != iomode && iomode != IOMODE_ANY)
2731 			continue;
2732 		if (pnfs_lseg_range_intersecting(&lseg->pls_range, range))
2733 			return lseg;
2734 	}
2735 	return NULL;
2736 }
2737 
2738 /* Find open file states whose mode matches that of the range */
2739 static bool
2740 pnfs_should_return_unused_layout(struct pnfs_layout_hdr *lo,
2741 				 const struct pnfs_layout_range *range)
2742 {
2743 	struct list_head *head;
2744 	struct nfs_open_context *ctx;
2745 	fmode_t mode = 0;
2746 
2747 	if (!pnfs_layout_can_be_returned(lo) ||
2748 	    !pnfs_find_first_lseg(lo, range, range->iomode))
2749 		return false;
2750 
2751 	head = &NFS_I(lo->plh_inode)->open_files;
2752 	list_for_each_entry_rcu(ctx, head, list) {
2753 		if (ctx->state)
2754 			mode |= ctx->state->state & (FMODE_READ|FMODE_WRITE);
2755 	}
2756 
2757 	switch (range->iomode) {
2758 	default:
2759 		break;
2760 	case IOMODE_READ:
2761 		mode &= ~FMODE_WRITE;
2762 		break;
2763 	case IOMODE_RW:
2764 		if (pnfs_find_first_lseg(lo, range, IOMODE_READ))
2765 			mode &= ~FMODE_READ;
2766 	}
2767 	return mode == 0;
2768 }
2769 
2770 static int pnfs_layout_return_unused_byserver(struct nfs_server *server,
2771 					      void *data)
2772 {
2773 	const struct pnfs_layout_range *range = data;
2774 	const struct cred *cred;
2775 	struct pnfs_layout_hdr *lo;
2776 	struct inode *inode;
2777 	nfs4_stateid stateid;
2778 	enum pnfs_iomode iomode;
2779 
2780 restart:
2781 	rcu_read_lock();
2782 	list_for_each_entry_rcu(lo, &server->layouts, plh_layouts) {
2783 		inode = lo->plh_inode;
2784 		if (!inode || !pnfs_layout_can_be_returned(lo) ||
2785 		    test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
2786 			continue;
2787 		spin_lock(&inode->i_lock);
2788 		if (!lo->plh_inode ||
2789 		    !pnfs_should_return_unused_layout(lo, range)) {
2790 			spin_unlock(&inode->i_lock);
2791 			continue;
2792 		}
2793 		pnfs_get_layout_hdr(lo);
2794 		pnfs_set_plh_return_info(lo, range->iomode, 0);
2795 		if (pnfs_mark_matching_lsegs_return(lo, &lo->plh_return_segs,
2796 						    range, 0) != 0 ||
2797 		    !pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode)) {
2798 			spin_unlock(&inode->i_lock);
2799 			rcu_read_unlock();
2800 			pnfs_put_layout_hdr(lo);
2801 			cond_resched();
2802 			goto restart;
2803 		}
2804 		spin_unlock(&inode->i_lock);
2805 		rcu_read_unlock();
2806 		pnfs_send_layoutreturn(lo, &stateid, &cred, iomode,
2807 				       PNFS_FL_LAYOUTRETURN_ASYNC);
2808 		pnfs_put_layout_hdr(lo);
2809 		cond_resched();
2810 		goto restart;
2811 	}
2812 	rcu_read_unlock();
2813 	return 0;
2814 }
2815 
2816 void
2817 pnfs_layout_return_unused_byclid(struct nfs_client *clp,
2818 				 enum pnfs_iomode iomode)
2819 {
2820 	struct pnfs_layout_range range = {
2821 		.iomode = iomode,
2822 		.offset = 0,
2823 		.length = NFS4_MAX_UINT64,
2824 	};
2825 
2826 	nfs_client_for_each_server(clp, pnfs_layout_return_unused_byserver,
2827 			&range);
2828 }
2829 
2830 /* Check if we have we have a valid layout but if there isn't an intersection
2831  * between the request and the pgio->pg_lseg, put this pgio->pg_lseg away.
2832  */
2833 void
2834 pnfs_generic_pg_check_layout(struct nfs_pageio_descriptor *pgio,
2835 			     struct nfs_page *req)
2836 {
2837 	if (pgio->pg_lseg == NULL ||
2838 	    (test_bit(NFS_LSEG_VALID, &pgio->pg_lseg->pls_flags) &&
2839 	    pnfs_lseg_request_intersecting(pgio->pg_lseg, req)))
2840 		return;
2841 	pnfs_put_lseg(pgio->pg_lseg);
2842 	pgio->pg_lseg = NULL;
2843 }
2844 EXPORT_SYMBOL_GPL(pnfs_generic_pg_check_layout);
2845 
2846 void
2847 pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
2848 {
2849 	u64 rd_size;
2850 
2851 	pnfs_generic_pg_check_layout(pgio, req);
2852 	if (pgio->pg_lseg == NULL) {
2853 		if (pgio->pg_dreq == NULL)
2854 			rd_size = i_size_read(pgio->pg_inode) - req_offset(req);
2855 		else
2856 			rd_size = nfs_dreq_bytes_left(pgio->pg_dreq,
2857 						      req_offset(req));
2858 
2859 		pgio->pg_lseg =
2860 			pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
2861 					   req_offset(req), rd_size,
2862 					   IOMODE_READ, false,
2863 					   nfs_io_gfp_mask());
2864 		if (IS_ERR(pgio->pg_lseg)) {
2865 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
2866 			pgio->pg_lseg = NULL;
2867 			return;
2868 		}
2869 	}
2870 	/* If no lseg, fall back to read through mds */
2871 	if (pgio->pg_lseg == NULL)
2872 		nfs_pageio_reset_read_mds(pgio);
2873 
2874 }
2875 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_read);
2876 
2877 void
2878 pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
2879 			   struct nfs_page *req, u64 wb_size)
2880 {
2881 	pnfs_generic_pg_check_layout(pgio, req);
2882 	if (pgio->pg_lseg == NULL) {
2883 		pgio->pg_lseg =
2884 			pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
2885 					   req_offset(req), wb_size, IOMODE_RW,
2886 					   false, nfs_io_gfp_mask());
2887 		if (IS_ERR(pgio->pg_lseg)) {
2888 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
2889 			pgio->pg_lseg = NULL;
2890 			return;
2891 		}
2892 	}
2893 	/* If no lseg, fall back to write through mds */
2894 	if (pgio->pg_lseg == NULL)
2895 		nfs_pageio_reset_write_mds(pgio);
2896 }
2897 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
2898 
2899 void
2900 pnfs_generic_pg_cleanup(struct nfs_pageio_descriptor *desc)
2901 {
2902 	if (desc->pg_lseg) {
2903 		pnfs_put_lseg(desc->pg_lseg);
2904 		desc->pg_lseg = NULL;
2905 	}
2906 }
2907 EXPORT_SYMBOL_GPL(pnfs_generic_pg_cleanup);
2908 
2909 /*
2910  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
2911  * of bytes (maximum @req->wb_bytes) that can be coalesced.
2912  */
2913 size_t
2914 pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio,
2915 		     struct nfs_page *prev, struct nfs_page *req)
2916 {
2917 	unsigned int size;
2918 	u64 seg_end, req_start, seg_left;
2919 
2920 	size = nfs_generic_pg_test(pgio, prev, req);
2921 	if (!size)
2922 		return 0;
2923 
2924 	/*
2925 	 * 'size' contains the number of bytes left in the current page (up
2926 	 * to the original size asked for in @req->wb_bytes).
2927 	 *
2928 	 * Calculate how many bytes are left in the layout segment
2929 	 * and if there are less bytes than 'size', return that instead.
2930 	 *
2931 	 * Please also note that 'end_offset' is actually the offset of the
2932 	 * first byte that lies outside the pnfs_layout_range. FIXME?
2933 	 *
2934 	 */
2935 	if (pgio->pg_lseg) {
2936 		seg_end = pnfs_end_offset(pgio->pg_lseg->pls_range.offset,
2937 				     pgio->pg_lseg->pls_range.length);
2938 		req_start = req_offset(req);
2939 
2940 		/* start of request is past the last byte of this segment */
2941 		if (req_start >= seg_end)
2942 			return 0;
2943 
2944 		/* adjust 'size' iff there are fewer bytes left in the
2945 		 * segment than what nfs_generic_pg_test returned */
2946 		seg_left = seg_end - req_start;
2947 		if (seg_left < size)
2948 			size = (unsigned int)seg_left;
2949 	}
2950 
2951 	return size;
2952 }
2953 EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);
2954 
2955 int pnfs_write_done_resend_to_mds(struct nfs_pgio_header *hdr)
2956 {
2957 	struct nfs_pageio_descriptor pgio;
2958 
2959 	/* Resend all requests through the MDS */
2960 	nfs_pageio_init_write(&pgio, hdr->inode, FLUSH_STABLE, true,
2961 			      hdr->completion_ops);
2962 	return nfs_pageio_resend(&pgio, hdr);
2963 }
2964 EXPORT_SYMBOL_GPL(pnfs_write_done_resend_to_mds);
2965 
2966 static void pnfs_ld_handle_write_error(struct nfs_pgio_header *hdr)
2967 {
2968 
2969 	dprintk("pnfs write error = %d\n", hdr->pnfs_error);
2970 	if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
2971 	    PNFS_LAYOUTRET_ON_ERROR) {
2972 		pnfs_return_layout(hdr->inode);
2973 	}
2974 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
2975 		hdr->task.tk_status = pnfs_write_done_resend_to_mds(hdr);
2976 }
2977 
2978 /*
2979  * Called by non rpc-based layout drivers
2980  */
2981 void pnfs_ld_write_done(struct nfs_pgio_header *hdr)
2982 {
2983 	if (likely(!hdr->pnfs_error)) {
2984 		pnfs_set_layoutcommit(hdr->inode, hdr->lseg,
2985 				hdr->mds_offset + hdr->res.count);
2986 		hdr->mds_ops->rpc_call_done(&hdr->task, hdr);
2987 	}
2988 	trace_nfs4_pnfs_write(hdr, hdr->pnfs_error);
2989 	if (unlikely(hdr->pnfs_error))
2990 		pnfs_ld_handle_write_error(hdr);
2991 	hdr->mds_ops->rpc_release(hdr);
2992 }
2993 EXPORT_SYMBOL_GPL(pnfs_ld_write_done);
2994 
2995 static void
2996 pnfs_write_through_mds(struct nfs_pageio_descriptor *desc,
2997 		struct nfs_pgio_header *hdr)
2998 {
2999 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
3000 
3001 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
3002 		list_splice_tail_init(&hdr->pages, &mirror->pg_list);
3003 		nfs_pageio_reset_write_mds(desc);
3004 		mirror->pg_recoalesce = 1;
3005 	}
3006 	hdr->completion_ops->completion(hdr);
3007 }
3008 
3009 static enum pnfs_try_status
3010 pnfs_try_to_write_data(struct nfs_pgio_header *hdr,
3011 			const struct rpc_call_ops *call_ops,
3012 			struct pnfs_layout_segment *lseg,
3013 			int how)
3014 {
3015 	struct inode *inode = hdr->inode;
3016 	enum pnfs_try_status trypnfs;
3017 	struct nfs_server *nfss = NFS_SERVER(inode);
3018 
3019 	hdr->mds_ops = call_ops;
3020 
3021 	dprintk("%s: Writing ino:%lu %u@%llu (how %d)\n", __func__,
3022 		inode->i_ino, hdr->args.count, hdr->args.offset, how);
3023 	trypnfs = nfss->pnfs_curr_ld->write_pagelist(hdr, how);
3024 	if (trypnfs != PNFS_NOT_ATTEMPTED)
3025 		nfs_inc_stats(inode, NFSIOS_PNFS_WRITE);
3026 	dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
3027 	return trypnfs;
3028 }
3029 
3030 static void
3031 pnfs_do_write(struct nfs_pageio_descriptor *desc,
3032 	      struct nfs_pgio_header *hdr, int how)
3033 {
3034 	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
3035 	struct pnfs_layout_segment *lseg = desc->pg_lseg;
3036 	enum pnfs_try_status trypnfs;
3037 
3038 	trypnfs = pnfs_try_to_write_data(hdr, call_ops, lseg, how);
3039 	switch (trypnfs) {
3040 	case PNFS_NOT_ATTEMPTED:
3041 		pnfs_write_through_mds(desc, hdr);
3042 		break;
3043 	case PNFS_ATTEMPTED:
3044 		break;
3045 	case PNFS_TRY_AGAIN:
3046 		/* cleanup hdr and prepare to redo pnfs */
3047 		if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
3048 			struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
3049 			list_splice_init(&hdr->pages, &mirror->pg_list);
3050 			mirror->pg_recoalesce = 1;
3051 		}
3052 		hdr->mds_ops->rpc_release(hdr);
3053 	}
3054 }
3055 
3056 static void pnfs_writehdr_free(struct nfs_pgio_header *hdr)
3057 {
3058 	pnfs_put_lseg(hdr->lseg);
3059 	nfs_pgio_header_free(hdr);
3060 }
3061 
3062 int
3063 pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
3064 {
3065 	struct nfs_pgio_header *hdr;
3066 	int ret;
3067 
3068 	hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
3069 	if (!hdr) {
3070 		desc->pg_error = -ENOMEM;
3071 		return desc->pg_error;
3072 	}
3073 	nfs_pgheader_init(desc, hdr, pnfs_writehdr_free);
3074 
3075 	hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
3076 	ret = nfs_generic_pgio(desc, hdr);
3077 	if (!ret)
3078 		pnfs_do_write(desc, hdr, desc->pg_ioflags);
3079 
3080 	return ret;
3081 }
3082 EXPORT_SYMBOL_GPL(pnfs_generic_pg_writepages);
3083 
3084 int pnfs_read_done_resend_to_mds(struct nfs_pgio_header *hdr)
3085 {
3086 	struct nfs_pageio_descriptor pgio;
3087 
3088 	/* Resend all requests through the MDS */
3089 	nfs_pageio_init_read(&pgio, hdr->inode, true, hdr->completion_ops);
3090 	return nfs_pageio_resend(&pgio, hdr);
3091 }
3092 EXPORT_SYMBOL_GPL(pnfs_read_done_resend_to_mds);
3093 
3094 static void pnfs_ld_handle_read_error(struct nfs_pgio_header *hdr)
3095 {
3096 	dprintk("pnfs read error = %d\n", hdr->pnfs_error);
3097 	if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
3098 	    PNFS_LAYOUTRET_ON_ERROR) {
3099 		pnfs_return_layout(hdr->inode);
3100 	}
3101 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
3102 		hdr->task.tk_status = pnfs_read_done_resend_to_mds(hdr);
3103 }
3104 
3105 /*
3106  * Called by non rpc-based layout drivers
3107  */
3108 void pnfs_ld_read_done(struct nfs_pgio_header *hdr)
3109 {
3110 	if (likely(!hdr->pnfs_error))
3111 		hdr->mds_ops->rpc_call_done(&hdr->task, hdr);
3112 	trace_nfs4_pnfs_read(hdr, hdr->pnfs_error);
3113 	if (unlikely(hdr->pnfs_error))
3114 		pnfs_ld_handle_read_error(hdr);
3115 	hdr->mds_ops->rpc_release(hdr);
3116 }
3117 EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
3118 
3119 static void
3120 pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
3121 		struct nfs_pgio_header *hdr)
3122 {
3123 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
3124 
3125 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
3126 		list_splice_tail_init(&hdr->pages, &mirror->pg_list);
3127 		nfs_pageio_reset_read_mds(desc);
3128 		mirror->pg_recoalesce = 1;
3129 	}
3130 	hdr->completion_ops->completion(hdr);
3131 }
3132 
3133 /*
3134  * Call the appropriate parallel I/O subsystem read function.
3135  */
3136 static enum pnfs_try_status
3137 pnfs_try_to_read_data(struct nfs_pgio_header *hdr,
3138 		       const struct rpc_call_ops *call_ops,
3139 		       struct pnfs_layout_segment *lseg)
3140 {
3141 	struct inode *inode = hdr->inode;
3142 	struct nfs_server *nfss = NFS_SERVER(inode);
3143 	enum pnfs_try_status trypnfs;
3144 
3145 	hdr->mds_ops = call_ops;
3146 
3147 	dprintk("%s: Reading ino:%lu %u@%llu\n",
3148 		__func__, inode->i_ino, hdr->args.count, hdr->args.offset);
3149 
3150 	trypnfs = nfss->pnfs_curr_ld->read_pagelist(hdr);
3151 	if (trypnfs != PNFS_NOT_ATTEMPTED)
3152 		nfs_inc_stats(inode, NFSIOS_PNFS_READ);
3153 	dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
3154 	return trypnfs;
3155 }
3156 
3157 /* Resend all requests through pnfs. */
3158 void pnfs_read_resend_pnfs(struct nfs_pgio_header *hdr,
3159 			   unsigned int mirror_idx)
3160 {
3161 	struct nfs_pageio_descriptor pgio;
3162 
3163 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
3164 		/* Prevent deadlocks with layoutreturn! */
3165 		pnfs_put_lseg(hdr->lseg);
3166 		hdr->lseg = NULL;
3167 
3168 		nfs_pageio_init_read(&pgio, hdr->inode, false,
3169 					hdr->completion_ops);
3170 		pgio.pg_mirror_idx = mirror_idx;
3171 		hdr->task.tk_status = nfs_pageio_resend(&pgio, hdr);
3172 	}
3173 }
3174 EXPORT_SYMBOL_GPL(pnfs_read_resend_pnfs);
3175 
3176 static void
3177 pnfs_do_read(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr)
3178 {
3179 	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
3180 	struct pnfs_layout_segment *lseg = desc->pg_lseg;
3181 	enum pnfs_try_status trypnfs;
3182 
3183 	trypnfs = pnfs_try_to_read_data(hdr, call_ops, lseg);
3184 	switch (trypnfs) {
3185 	case PNFS_NOT_ATTEMPTED:
3186 		pnfs_read_through_mds(desc, hdr);
3187 		break;
3188 	case PNFS_ATTEMPTED:
3189 		break;
3190 	case PNFS_TRY_AGAIN:
3191 		/* cleanup hdr and prepare to redo pnfs */
3192 		if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
3193 			struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
3194 			list_splice_init(&hdr->pages, &mirror->pg_list);
3195 			mirror->pg_recoalesce = 1;
3196 		}
3197 		hdr->mds_ops->rpc_release(hdr);
3198 	}
3199 }
3200 
3201 static void pnfs_readhdr_free(struct nfs_pgio_header *hdr)
3202 {
3203 	pnfs_put_lseg(hdr->lseg);
3204 	nfs_pgio_header_free(hdr);
3205 }
3206 
3207 int
3208 pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
3209 {
3210 	struct nfs_pgio_header *hdr;
3211 	int ret;
3212 
3213 	hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
3214 	if (!hdr) {
3215 		desc->pg_error = -ENOMEM;
3216 		return desc->pg_error;
3217 	}
3218 	nfs_pgheader_init(desc, hdr, pnfs_readhdr_free);
3219 	hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
3220 	ret = nfs_generic_pgio(desc, hdr);
3221 	if (!ret)
3222 		pnfs_do_read(desc, hdr);
3223 	return ret;
3224 }
3225 EXPORT_SYMBOL_GPL(pnfs_generic_pg_readpages);
3226 
3227 static void pnfs_clear_layoutcommitting(struct inode *inode)
3228 {
3229 	unsigned long *bitlock = &NFS_I(inode)->flags;
3230 
3231 	clear_bit_unlock(NFS_INO_LAYOUTCOMMITTING, bitlock);
3232 	smp_mb__after_atomic();
3233 	wake_up_bit(bitlock, NFS_INO_LAYOUTCOMMITTING);
3234 }
3235 
3236 /*
3237  * There can be multiple RW segments.
3238  */
3239 static void pnfs_list_write_lseg(struct inode *inode, struct list_head *listp)
3240 {
3241 	struct pnfs_layout_segment *lseg;
3242 
3243 	list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) {
3244 		if (lseg->pls_range.iomode == IOMODE_RW &&
3245 		    test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
3246 			list_add(&lseg->pls_lc_list, listp);
3247 	}
3248 }
3249 
3250 static void pnfs_list_write_lseg_done(struct inode *inode, struct list_head *listp)
3251 {
3252 	struct pnfs_layout_segment *lseg, *tmp;
3253 
3254 	/* Matched by references in pnfs_set_layoutcommit */
3255 	list_for_each_entry_safe(lseg, tmp, listp, pls_lc_list) {
3256 		list_del_init(&lseg->pls_lc_list);
3257 		pnfs_put_lseg(lseg);
3258 	}
3259 
3260 	pnfs_clear_layoutcommitting(inode);
3261 }
3262 
3263 void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg)
3264 {
3265 	pnfs_layout_io_set_failed(lseg->pls_layout, lseg->pls_range.iomode);
3266 }
3267 EXPORT_SYMBOL_GPL(pnfs_set_lo_fail);
3268 
3269 void
3270 pnfs_set_layoutcommit(struct inode *inode, struct pnfs_layout_segment *lseg,
3271 		loff_t end_pos)
3272 {
3273 	struct nfs_inode *nfsi = NFS_I(inode);
3274 	bool mark_as_dirty = false;
3275 
3276 	spin_lock(&inode->i_lock);
3277 	if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
3278 		nfsi->layout->plh_lwb = end_pos;
3279 		mark_as_dirty = true;
3280 		dprintk("%s: Set layoutcommit for inode %lu ",
3281 			__func__, inode->i_ino);
3282 	} else if (end_pos > nfsi->layout->plh_lwb)
3283 		nfsi->layout->plh_lwb = end_pos;
3284 	if (!test_and_set_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags)) {
3285 		/* references matched in nfs4_layoutcommit_release */
3286 		pnfs_get_lseg(lseg);
3287 	}
3288 	spin_unlock(&inode->i_lock);
3289 	dprintk("%s: lseg %p end_pos %llu\n",
3290 		__func__, lseg, nfsi->layout->plh_lwb);
3291 
3292 	/* if pnfs_layoutcommit_inode() runs between inode locks, the next one
3293 	 * will be a noop because NFS_INO_LAYOUTCOMMIT will not be set */
3294 	if (mark_as_dirty)
3295 		mark_inode_dirty_sync(inode);
3296 }
3297 EXPORT_SYMBOL_GPL(pnfs_set_layoutcommit);
3298 
3299 void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data)
3300 {
3301 	struct nfs_server *nfss = NFS_SERVER(data->args.inode);
3302 
3303 	if (nfss->pnfs_curr_ld->cleanup_layoutcommit)
3304 		nfss->pnfs_curr_ld->cleanup_layoutcommit(data);
3305 	pnfs_list_write_lseg_done(data->args.inode, &data->lseg_list);
3306 }
3307 
3308 /*
3309  * For the LAYOUT4_NFSV4_1_FILES layout type, NFS_DATA_SYNC WRITEs and
3310  * NFS_UNSTABLE WRITEs with a COMMIT to data servers must store enough
3311  * data to disk to allow the server to recover the data if it crashes.
3312  * LAYOUTCOMMIT is only needed when the NFL4_UFLG_COMMIT_THRU_MDS flag
3313  * is off, and a COMMIT is sent to a data server, or
3314  * if WRITEs to a data server return NFS_DATA_SYNC.
3315  */
3316 int
3317 pnfs_layoutcommit_inode(struct inode *inode, bool sync)
3318 {
3319 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
3320 	struct nfs4_layoutcommit_data *data;
3321 	struct nfs_inode *nfsi = NFS_I(inode);
3322 	loff_t end_pos;
3323 	int status;
3324 
3325 	if (!pnfs_layoutcommit_outstanding(inode))
3326 		return 0;
3327 
3328 	dprintk("--> %s inode %lu\n", __func__, inode->i_ino);
3329 
3330 	status = -EAGAIN;
3331 	if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
3332 		if (!sync)
3333 			goto out;
3334 		status = wait_on_bit_lock_action(&nfsi->flags,
3335 				NFS_INO_LAYOUTCOMMITTING,
3336 				nfs_wait_bit_killable,
3337 				TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
3338 		if (status)
3339 			goto out;
3340 	}
3341 
3342 	status = -ENOMEM;
3343 	/* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
3344 	data = kzalloc(sizeof(*data), nfs_io_gfp_mask());
3345 	if (!data)
3346 		goto clear_layoutcommitting;
3347 
3348 	status = 0;
3349 	spin_lock(&inode->i_lock);
3350 	if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
3351 		goto out_unlock;
3352 
3353 	INIT_LIST_HEAD(&data->lseg_list);
3354 	pnfs_list_write_lseg(inode, &data->lseg_list);
3355 
3356 	end_pos = nfsi->layout->plh_lwb;
3357 
3358 	nfs4_stateid_copy(&data->args.stateid, &nfsi->layout->plh_stateid);
3359 	data->cred = get_cred(nfsi->layout->plh_lc_cred);
3360 	spin_unlock(&inode->i_lock);
3361 
3362 	data->args.inode = inode;
3363 	nfs_fattr_init(&data->fattr);
3364 	data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
3365 	data->res.fattr = &data->fattr;
3366 	if (end_pos != 0)
3367 		data->args.lastbytewritten = end_pos - 1;
3368 	else
3369 		data->args.lastbytewritten = U64_MAX;
3370 	data->res.server = NFS_SERVER(inode);
3371 
3372 	if (ld->prepare_layoutcommit) {
3373 		status = ld->prepare_layoutcommit(&data->args);
3374 		if (status) {
3375 			put_cred(data->cred);
3376 			spin_lock(&inode->i_lock);
3377 			set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags);
3378 			if (end_pos > nfsi->layout->plh_lwb)
3379 				nfsi->layout->plh_lwb = end_pos;
3380 			goto out_unlock;
3381 		}
3382 	}
3383 
3384 
3385 	status = nfs4_proc_layoutcommit(data, sync);
3386 out:
3387 	if (status)
3388 		mark_inode_dirty_sync(inode);
3389 	dprintk("<-- %s status %d\n", __func__, status);
3390 	return status;
3391 out_unlock:
3392 	spin_unlock(&inode->i_lock);
3393 	kfree(data);
3394 clear_layoutcommitting:
3395 	pnfs_clear_layoutcommitting(inode);
3396 	goto out;
3397 }
3398 EXPORT_SYMBOL_GPL(pnfs_layoutcommit_inode);
3399 
3400 int
3401 pnfs_generic_sync(struct inode *inode, bool datasync)
3402 {
3403 	return pnfs_layoutcommit_inode(inode, true);
3404 }
3405 EXPORT_SYMBOL_GPL(pnfs_generic_sync);
3406 
3407 struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
3408 {
3409 	struct nfs4_threshold *thp;
3410 
3411 	thp = kzalloc(sizeof(*thp), nfs_io_gfp_mask());
3412 	if (!thp) {
3413 		dprintk("%s mdsthreshold allocation failed\n", __func__);
3414 		return NULL;
3415 	}
3416 	return thp;
3417 }
3418 
3419 #if IS_ENABLED(CONFIG_NFS_V4_2)
3420 int
3421 pnfs_report_layoutstat(struct inode *inode, gfp_t gfp_flags)
3422 {
3423 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
3424 	struct nfs_server *server = NFS_SERVER(inode);
3425 	struct nfs_inode *nfsi = NFS_I(inode);
3426 	struct nfs42_layoutstat_data *data;
3427 	struct pnfs_layout_hdr *hdr;
3428 	int status = 0;
3429 
3430 	if (!pnfs_enabled_sb(server) || !ld->prepare_layoutstats)
3431 		goto out;
3432 
3433 	if (!nfs_server_capable(inode, NFS_CAP_LAYOUTSTATS))
3434 		goto out;
3435 
3436 	if (test_and_set_bit(NFS_INO_LAYOUTSTATS, &nfsi->flags))
3437 		goto out;
3438 
3439 	spin_lock(&inode->i_lock);
3440 	if (!NFS_I(inode)->layout) {
3441 		spin_unlock(&inode->i_lock);
3442 		goto out_clear_layoutstats;
3443 	}
3444 	hdr = NFS_I(inode)->layout;
3445 	pnfs_get_layout_hdr(hdr);
3446 	spin_unlock(&inode->i_lock);
3447 
3448 	data = kzalloc(sizeof(*data), gfp_flags);
3449 	if (!data) {
3450 		status = -ENOMEM;
3451 		goto out_put;
3452 	}
3453 
3454 	data->args.fh = NFS_FH(inode);
3455 	data->args.inode = inode;
3456 	status = ld->prepare_layoutstats(&data->args);
3457 	if (status)
3458 		goto out_free;
3459 
3460 	status = nfs42_proc_layoutstats_generic(NFS_SERVER(inode), data);
3461 
3462 out:
3463 	dprintk("%s returns %d\n", __func__, status);
3464 	return status;
3465 
3466 out_free:
3467 	kfree(data);
3468 out_put:
3469 	pnfs_put_layout_hdr(hdr);
3470 out_clear_layoutstats:
3471 	smp_mb__before_atomic();
3472 	clear_bit(NFS_INO_LAYOUTSTATS, &nfsi->flags);
3473 	smp_mb__after_atomic();
3474 	goto out;
3475 }
3476 EXPORT_SYMBOL_GPL(pnfs_report_layoutstat);
3477 #endif
3478 
3479 unsigned int layoutstats_timer;
3480 module_param(layoutstats_timer, uint, 0644);
3481 EXPORT_SYMBOL_GPL(layoutstats_timer);
3482