xref: /openbmc/linux/fs/nfs/pnfs.c (revision 66a28915)
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 
65 /* Return the registered pnfs layout driver module matching given id */
66 static struct pnfs_layoutdriver_type *
67 find_pnfs_driver_locked(u32 id)
68 {
69 	struct pnfs_layoutdriver_type *local;
70 
71 	list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid)
72 		if (local->id == id)
73 			goto out;
74 	local = NULL;
75 out:
76 	dprintk("%s: Searching for id %u, found %p\n", __func__, id, local);
77 	return local;
78 }
79 
80 static struct pnfs_layoutdriver_type *
81 find_pnfs_driver(u32 id)
82 {
83 	struct pnfs_layoutdriver_type *local;
84 
85 	spin_lock(&pnfs_spinlock);
86 	local = find_pnfs_driver_locked(id);
87 	if (local != NULL && !try_module_get(local->owner)) {
88 		dprintk("%s: Could not grab reference on module\n", __func__);
89 		local = NULL;
90 	}
91 	spin_unlock(&pnfs_spinlock);
92 	return local;
93 }
94 
95 void
96 unset_pnfs_layoutdriver(struct nfs_server *nfss)
97 {
98 	if (nfss->pnfs_curr_ld) {
99 		if (nfss->pnfs_curr_ld->clear_layoutdriver)
100 			nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
101 		/* Decrement the MDS count. Purge the deviceid cache if zero */
102 		if (atomic_dec_and_test(&nfss->nfs_client->cl_mds_count))
103 			nfs4_deviceid_purge_client(nfss->nfs_client);
104 		module_put(nfss->pnfs_curr_ld->owner);
105 	}
106 	nfss->pnfs_curr_ld = NULL;
107 }
108 
109 /*
110  * When the server sends a list of layout types, we choose one in the order
111  * given in the list below.
112  *
113  * FIXME: should this list be configurable in some fashion? module param?
114  * 	  mount option? something else?
115  */
116 static const u32 ld_prefs[] = {
117 	LAYOUT_SCSI,
118 	LAYOUT_BLOCK_VOLUME,
119 	LAYOUT_OSD2_OBJECTS,
120 	LAYOUT_FLEX_FILES,
121 	LAYOUT_NFSV4_1_FILES,
122 	0
123 };
124 
125 static int
126 ld_cmp(const void *e1, const void *e2)
127 {
128 	u32 ld1 = *((u32 *)e1);
129 	u32 ld2 = *((u32 *)e2);
130 	int i;
131 
132 	for (i = 0; ld_prefs[i] != 0; i++) {
133 		if (ld1 == ld_prefs[i])
134 			return -1;
135 
136 		if (ld2 == ld_prefs[i])
137 			return 1;
138 	}
139 	return 0;
140 }
141 
142 /*
143  * Try to set the server's pnfs module to the pnfs layout type specified by id.
144  * Currently only one pNFS layout driver per filesystem is supported.
145  *
146  * @ids array of layout types supported by MDS.
147  */
148 void
149 set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
150 		      struct nfs_fsinfo *fsinfo)
151 {
152 	struct pnfs_layoutdriver_type *ld_type = NULL;
153 	u32 id;
154 	int i;
155 
156 	if (fsinfo->nlayouttypes == 0)
157 		goto out_no_driver;
158 	if (!(server->nfs_client->cl_exchange_flags &
159 		 (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) {
160 		printk(KERN_ERR "NFS: %s: cl_exchange_flags 0x%x\n",
161 			__func__, server->nfs_client->cl_exchange_flags);
162 		goto out_no_driver;
163 	}
164 
165 	sort(fsinfo->layouttype, fsinfo->nlayouttypes,
166 		sizeof(*fsinfo->layouttype), ld_cmp, NULL);
167 
168 	for (i = 0; i < fsinfo->nlayouttypes; i++) {
169 		id = fsinfo->layouttype[i];
170 		ld_type = find_pnfs_driver(id);
171 		if (!ld_type) {
172 			request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX,
173 					id);
174 			ld_type = find_pnfs_driver(id);
175 		}
176 		if (ld_type)
177 			break;
178 	}
179 
180 	if (!ld_type) {
181 		dprintk("%s: No pNFS module found!\n", __func__);
182 		goto out_no_driver;
183 	}
184 
185 	server->pnfs_curr_ld = ld_type;
186 	if (ld_type->set_layoutdriver
187 	    && ld_type->set_layoutdriver(server, mntfh)) {
188 		printk(KERN_ERR "NFS: %s: Error initializing pNFS layout "
189 			"driver %u.\n", __func__, id);
190 		module_put(ld_type->owner);
191 		goto out_no_driver;
192 	}
193 	/* Bump the MDS count */
194 	atomic_inc(&server->nfs_client->cl_mds_count);
195 
196 	dprintk("%s: pNFS module for %u set\n", __func__, id);
197 	return;
198 
199 out_no_driver:
200 	dprintk("%s: Using NFSv4 I/O\n", __func__);
201 	server->pnfs_curr_ld = NULL;
202 }
203 
204 int
205 pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
206 {
207 	int status = -EINVAL;
208 	struct pnfs_layoutdriver_type *tmp;
209 
210 	if (ld_type->id == 0) {
211 		printk(KERN_ERR "NFS: %s id 0 is reserved\n", __func__);
212 		return status;
213 	}
214 	if (!ld_type->alloc_lseg || !ld_type->free_lseg) {
215 		printk(KERN_ERR "NFS: %s Layout driver must provide "
216 		       "alloc_lseg and free_lseg.\n", __func__);
217 		return status;
218 	}
219 
220 	spin_lock(&pnfs_spinlock);
221 	tmp = find_pnfs_driver_locked(ld_type->id);
222 	if (!tmp) {
223 		list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl);
224 		status = 0;
225 		dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id,
226 			ld_type->name);
227 	} else {
228 		printk(KERN_ERR "NFS: %s Module with id %d already loaded!\n",
229 			__func__, ld_type->id);
230 	}
231 	spin_unlock(&pnfs_spinlock);
232 
233 	return status;
234 }
235 EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver);
236 
237 void
238 pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
239 {
240 	dprintk("%s Deregistering id:%u\n", __func__, ld_type->id);
241 	spin_lock(&pnfs_spinlock);
242 	list_del(&ld_type->pnfs_tblid);
243 	spin_unlock(&pnfs_spinlock);
244 }
245 EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);
246 
247 /*
248  * pNFS client layout cache
249  */
250 
251 /* Need to hold i_lock if caller does not already hold reference */
252 void
253 pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo)
254 {
255 	refcount_inc(&lo->plh_refcount);
256 }
257 
258 static struct pnfs_layout_hdr *
259 pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
260 {
261 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
262 	return ld->alloc_layout_hdr(ino, gfp_flags);
263 }
264 
265 static void
266 pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
267 {
268 	struct nfs_server *server = NFS_SERVER(lo->plh_inode);
269 	struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
270 
271 	if (test_and_clear_bit(NFS_LAYOUT_HASHED, &lo->plh_flags)) {
272 		struct nfs_client *clp = server->nfs_client;
273 
274 		spin_lock(&clp->cl_lock);
275 		list_del_rcu(&lo->plh_layouts);
276 		spin_unlock(&clp->cl_lock);
277 	}
278 	put_cred(lo->plh_lc_cred);
279 	return ld->free_layout_hdr(lo);
280 }
281 
282 static void
283 pnfs_detach_layout_hdr(struct pnfs_layout_hdr *lo)
284 {
285 	struct nfs_inode *nfsi = NFS_I(lo->plh_inode);
286 	dprintk("%s: freeing layout cache %p\n", __func__, lo);
287 	nfsi->layout = NULL;
288 	/* Reset MDS Threshold I/O counters */
289 	nfsi->write_io = 0;
290 	nfsi->read_io = 0;
291 }
292 
293 void
294 pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
295 {
296 	struct inode *inode;
297 	unsigned long i_state;
298 
299 	if (!lo)
300 		return;
301 	inode = lo->plh_inode;
302 	pnfs_layoutreturn_before_put_layout_hdr(lo);
303 
304 	if (refcount_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
305 		if (!list_empty(&lo->plh_segs))
306 			WARN_ONCE(1, "NFS: BUG unfreed layout segments.\n");
307 		pnfs_detach_layout_hdr(lo);
308 		i_state = inode->i_state;
309 		spin_unlock(&inode->i_lock);
310 		pnfs_free_layout_hdr(lo);
311 		/* Notify pnfs_destroy_layout_final() that we're done */
312 		if (i_state & (I_FREEING | I_CLEAR))
313 			wake_up_var(lo);
314 	}
315 }
316 
317 static struct inode *
318 pnfs_grab_inode_layout_hdr(struct pnfs_layout_hdr *lo)
319 {
320 	struct inode *inode = igrab(lo->plh_inode);
321 	if (inode)
322 		return inode;
323 	set_bit(NFS_LAYOUT_INODE_FREEING, &lo->plh_flags);
324 	return NULL;
325 }
326 
327 static void
328 pnfs_set_plh_return_info(struct pnfs_layout_hdr *lo, enum pnfs_iomode iomode,
329 			 u32 seq)
330 {
331 	if (lo->plh_return_iomode != 0 && lo->plh_return_iomode != iomode)
332 		iomode = IOMODE_ANY;
333 	lo->plh_return_iomode = iomode;
334 	set_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags);
335 	if (seq != 0) {
336 		WARN_ON_ONCE(lo->plh_return_seq != 0 && lo->plh_return_seq != seq);
337 		lo->plh_return_seq = seq;
338 	}
339 }
340 
341 static void
342 pnfs_clear_layoutreturn_info(struct pnfs_layout_hdr *lo)
343 {
344 	struct pnfs_layout_segment *lseg;
345 	lo->plh_return_iomode = 0;
346 	lo->plh_return_seq = 0;
347 	clear_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags);
348 	list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
349 		if (!test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
350 			continue;
351 		pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
352 	}
353 }
354 
355 static void pnfs_clear_layoutreturn_waitbit(struct pnfs_layout_hdr *lo)
356 {
357 	clear_bit_unlock(NFS_LAYOUT_RETURN, &lo->plh_flags);
358 	clear_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags);
359 	smp_mb__after_atomic();
360 	wake_up_bit(&lo->plh_flags, NFS_LAYOUT_RETURN);
361 	rpc_wake_up(&NFS_SERVER(lo->plh_inode)->roc_rpcwaitq);
362 }
363 
364 static void
365 pnfs_clear_lseg_state(struct pnfs_layout_segment *lseg,
366 		struct list_head *free_me)
367 {
368 	clear_bit(NFS_LSEG_ROC, &lseg->pls_flags);
369 	clear_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
370 	if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags))
371 		pnfs_lseg_dec_and_remove_zero(lseg, free_me);
372 	if (test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
373 		pnfs_lseg_dec_and_remove_zero(lseg, free_me);
374 }
375 
376 /*
377  * Update the seqid of a layout stateid after receiving
378  * NFS4ERR_OLD_STATEID
379  */
380 bool nfs4_layout_refresh_old_stateid(nfs4_stateid *dst,
381 		struct pnfs_layout_range *dst_range,
382 		struct inode *inode)
383 {
384 	struct pnfs_layout_hdr *lo;
385 	struct pnfs_layout_range range = {
386 		.iomode = IOMODE_ANY,
387 		.offset = 0,
388 		.length = NFS4_MAX_UINT64,
389 	};
390 	bool ret = false;
391 	LIST_HEAD(head);
392 	int err;
393 
394 	spin_lock(&inode->i_lock);
395 	lo = NFS_I(inode)->layout;
396 	if (lo &&  pnfs_layout_is_valid(lo) &&
397 	    nfs4_stateid_match_other(dst, &lo->plh_stateid)) {
398 		/* Is our call using the most recent seqid? If so, bump it */
399 		if (!nfs4_stateid_is_newer(&lo->plh_stateid, dst)) {
400 			nfs4_stateid_seqid_inc(dst);
401 			ret = true;
402 			goto out;
403 		}
404 		/* Try to update the seqid to the most recent */
405 		err = pnfs_mark_matching_lsegs_return(lo, &head, &range, 0);
406 		if (err != -EBUSY) {
407 			dst->seqid = lo->plh_stateid.seqid;
408 			*dst_range = range;
409 			ret = true;
410 		}
411 	}
412 out:
413 	spin_unlock(&inode->i_lock);
414 	pnfs_free_lseg_list(&head);
415 	return ret;
416 }
417 
418 /*
419  * Mark a pnfs_layout_hdr and all associated layout segments as invalid
420  *
421  * In order to continue using the pnfs_layout_hdr, a full recovery
422  * is required.
423  * Note that caller must hold inode->i_lock.
424  */
425 int
426 pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
427 		struct list_head *lseg_list)
428 {
429 	struct pnfs_layout_range range = {
430 		.iomode = IOMODE_ANY,
431 		.offset = 0,
432 		.length = NFS4_MAX_UINT64,
433 	};
434 	struct pnfs_layout_segment *lseg, *next;
435 
436 	set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
437 	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
438 		pnfs_clear_lseg_state(lseg, lseg_list);
439 	pnfs_clear_layoutreturn_info(lo);
440 	pnfs_free_returned_lsegs(lo, lseg_list, &range, 0);
441 	if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags) &&
442 	    !test_and_set_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags))
443 		pnfs_clear_layoutreturn_waitbit(lo);
444 	return !list_empty(&lo->plh_segs);
445 }
446 
447 static int
448 pnfs_iomode_to_fail_bit(u32 iomode)
449 {
450 	return iomode == IOMODE_RW ?
451 		NFS_LAYOUT_RW_FAILED : NFS_LAYOUT_RO_FAILED;
452 }
453 
454 static void
455 pnfs_layout_set_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
456 {
457 	lo->plh_retry_timestamp = jiffies;
458 	if (!test_and_set_bit(fail_bit, &lo->plh_flags))
459 		refcount_inc(&lo->plh_refcount);
460 }
461 
462 static void
463 pnfs_layout_clear_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
464 {
465 	if (test_and_clear_bit(fail_bit, &lo->plh_flags))
466 		refcount_dec(&lo->plh_refcount);
467 }
468 
469 static void
470 pnfs_layout_io_set_failed(struct pnfs_layout_hdr *lo, u32 iomode)
471 {
472 	struct inode *inode = lo->plh_inode;
473 	struct pnfs_layout_range range = {
474 		.iomode = iomode,
475 		.offset = 0,
476 		.length = NFS4_MAX_UINT64,
477 	};
478 	LIST_HEAD(head);
479 
480 	spin_lock(&inode->i_lock);
481 	pnfs_layout_set_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
482 	pnfs_mark_matching_lsegs_invalid(lo, &head, &range, 0);
483 	spin_unlock(&inode->i_lock);
484 	pnfs_free_lseg_list(&head);
485 	dprintk("%s Setting layout IOMODE_%s fail bit\n", __func__,
486 			iomode == IOMODE_RW ?  "RW" : "READ");
487 }
488 
489 static bool
490 pnfs_layout_io_test_failed(struct pnfs_layout_hdr *lo, u32 iomode)
491 {
492 	unsigned long start, end;
493 	int fail_bit = pnfs_iomode_to_fail_bit(iomode);
494 
495 	if (test_bit(fail_bit, &lo->plh_flags) == 0)
496 		return false;
497 	end = jiffies;
498 	start = end - PNFS_LAYOUTGET_RETRY_TIMEOUT;
499 	if (!time_in_range(lo->plh_retry_timestamp, start, end)) {
500 		/* It is time to retry the failed layoutgets */
501 		pnfs_layout_clear_fail_bit(lo, fail_bit);
502 		return false;
503 	}
504 	return true;
505 }
506 
507 static void
508 pnfs_init_lseg(struct pnfs_layout_hdr *lo, struct pnfs_layout_segment *lseg,
509 		const struct pnfs_layout_range *range,
510 		const nfs4_stateid *stateid)
511 {
512 	INIT_LIST_HEAD(&lseg->pls_list);
513 	INIT_LIST_HEAD(&lseg->pls_lc_list);
514 	INIT_LIST_HEAD(&lseg->pls_commits);
515 	refcount_set(&lseg->pls_refcount, 1);
516 	set_bit(NFS_LSEG_VALID, &lseg->pls_flags);
517 	lseg->pls_layout = lo;
518 	lseg->pls_range = *range;
519 	lseg->pls_seq = be32_to_cpu(stateid->seqid);
520 }
521 
522 static void pnfs_free_lseg(struct pnfs_layout_segment *lseg)
523 {
524 	if (lseg != NULL) {
525 		struct inode *inode = lseg->pls_layout->plh_inode;
526 		NFS_SERVER(inode)->pnfs_curr_ld->free_lseg(lseg);
527 	}
528 }
529 
530 static void
531 pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo,
532 		struct pnfs_layout_segment *lseg)
533 {
534 	WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
535 	list_del_init(&lseg->pls_list);
536 	/* Matched by pnfs_get_layout_hdr in pnfs_layout_insert_lseg */
537 	refcount_dec(&lo->plh_refcount);
538 	if (test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
539 		return;
540 	if (list_empty(&lo->plh_segs) &&
541 	    !test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags) &&
542 	    !test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
543 		if (atomic_read(&lo->plh_outstanding) == 0)
544 			set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
545 		clear_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
546 	}
547 }
548 
549 static bool
550 pnfs_cache_lseg_for_layoutreturn(struct pnfs_layout_hdr *lo,
551 		struct pnfs_layout_segment *lseg)
552 {
553 	if (test_and_clear_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags) &&
554 	    pnfs_layout_is_valid(lo)) {
555 		pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
556 		list_move_tail(&lseg->pls_list, &lo->plh_return_segs);
557 		return true;
558 	}
559 	return false;
560 }
561 
562 void
563 pnfs_put_lseg(struct pnfs_layout_segment *lseg)
564 {
565 	struct pnfs_layout_hdr *lo;
566 	struct inode *inode;
567 
568 	if (!lseg)
569 		return;
570 
571 	dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
572 		refcount_read(&lseg->pls_refcount),
573 		test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
574 
575 	lo = lseg->pls_layout;
576 	inode = lo->plh_inode;
577 
578 	if (refcount_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
579 		if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
580 			spin_unlock(&inode->i_lock);
581 			return;
582 		}
583 		pnfs_get_layout_hdr(lo);
584 		pnfs_layout_remove_lseg(lo, lseg);
585 		if (pnfs_cache_lseg_for_layoutreturn(lo, lseg))
586 			lseg = NULL;
587 		spin_unlock(&inode->i_lock);
588 		pnfs_free_lseg(lseg);
589 		pnfs_put_layout_hdr(lo);
590 	}
591 }
592 EXPORT_SYMBOL_GPL(pnfs_put_lseg);
593 
594 /*
595  * is l2 fully contained in l1?
596  *   start1                             end1
597  *   [----------------------------------)
598  *           start2           end2
599  *           [----------------)
600  */
601 static bool
602 pnfs_lseg_range_contained(const struct pnfs_layout_range *l1,
603 		 const struct pnfs_layout_range *l2)
604 {
605 	u64 start1 = l1->offset;
606 	u64 end1 = pnfs_end_offset(start1, l1->length);
607 	u64 start2 = l2->offset;
608 	u64 end2 = pnfs_end_offset(start2, l2->length);
609 
610 	return (start1 <= start2) && (end1 >= end2);
611 }
612 
613 static bool pnfs_lseg_dec_and_remove_zero(struct pnfs_layout_segment *lseg,
614 		struct list_head *tmp_list)
615 {
616 	if (!refcount_dec_and_test(&lseg->pls_refcount))
617 		return false;
618 	pnfs_layout_remove_lseg(lseg->pls_layout, lseg);
619 	list_add(&lseg->pls_list, tmp_list);
620 	return true;
621 }
622 
623 /* Returns 1 if lseg is removed from list, 0 otherwise */
624 static int mark_lseg_invalid(struct pnfs_layout_segment *lseg,
625 			     struct list_head *tmp_list)
626 {
627 	int rv = 0;
628 
629 	if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
630 		/* Remove the reference keeping the lseg in the
631 		 * list.  It will now be removed when all
632 		 * outstanding io is finished.
633 		 */
634 		dprintk("%s: lseg %p ref %d\n", __func__, lseg,
635 			refcount_read(&lseg->pls_refcount));
636 		if (pnfs_lseg_dec_and_remove_zero(lseg, tmp_list))
637 			rv = 1;
638 	}
639 	return rv;
640 }
641 
642 /*
643  * Compare 2 layout stateid sequence ids, to see which is newer,
644  * taking into account wraparound issues.
645  */
646 static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
647 {
648 	return (s32)(s1 - s2) > 0;
649 }
650 
651 static bool
652 pnfs_should_free_range(const struct pnfs_layout_range *lseg_range,
653 		 const struct pnfs_layout_range *recall_range)
654 {
655 	return (recall_range->iomode == IOMODE_ANY ||
656 		lseg_range->iomode == recall_range->iomode) &&
657 	       pnfs_lseg_range_intersecting(lseg_range, recall_range);
658 }
659 
660 static bool
661 pnfs_match_lseg_recall(const struct pnfs_layout_segment *lseg,
662 		const struct pnfs_layout_range *recall_range,
663 		u32 seq)
664 {
665 	if (seq != 0 && pnfs_seqid_is_newer(lseg->pls_seq, seq))
666 		return false;
667 	if (recall_range == NULL)
668 		return true;
669 	return pnfs_should_free_range(&lseg->pls_range, recall_range);
670 }
671 
672 /**
673  * pnfs_mark_matching_lsegs_invalid - tear down lsegs or mark them for later
674  * @lo: layout header containing the lsegs
675  * @tmp_list: list head where doomed lsegs should go
676  * @recall_range: optional recall range argument to match (may be NULL)
677  * @seq: only invalidate lsegs obtained prior to this sequence (may be 0)
678  *
679  * Walk the list of lsegs in the layout header, and tear down any that should
680  * be destroyed. If "recall_range" is specified then the segment must match
681  * that range. If "seq" is non-zero, then only match segments that were handed
682  * out at or before that sequence.
683  *
684  * Returns number of matching invalid lsegs remaining in list after scanning
685  * it and purging them.
686  */
687 int
688 pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
689 			    struct list_head *tmp_list,
690 			    const struct pnfs_layout_range *recall_range,
691 			    u32 seq)
692 {
693 	struct pnfs_layout_segment *lseg, *next;
694 	int remaining = 0;
695 
696 	dprintk("%s:Begin lo %p\n", __func__, lo);
697 
698 	if (list_empty(&lo->plh_segs))
699 		return 0;
700 	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
701 		if (pnfs_match_lseg_recall(lseg, recall_range, seq)) {
702 			dprintk("%s: freeing lseg %p iomode %d seq %u "
703 				"offset %llu length %llu\n", __func__,
704 				lseg, lseg->pls_range.iomode, lseg->pls_seq,
705 				lseg->pls_range.offset, lseg->pls_range.length);
706 			if (!mark_lseg_invalid(lseg, tmp_list))
707 				remaining++;
708 		}
709 	dprintk("%s:Return %i\n", __func__, remaining);
710 	return remaining;
711 }
712 
713 static void
714 pnfs_free_returned_lsegs(struct pnfs_layout_hdr *lo,
715 		struct list_head *free_me,
716 		const struct pnfs_layout_range *range,
717 		u32 seq)
718 {
719 	struct pnfs_layout_segment *lseg, *next;
720 
721 	list_for_each_entry_safe(lseg, next, &lo->plh_return_segs, pls_list) {
722 		if (pnfs_match_lseg_recall(lseg, range, seq))
723 			list_move_tail(&lseg->pls_list, free_me);
724 	}
725 }
726 
727 /* note free_me must contain lsegs from a single layout_hdr */
728 void
729 pnfs_free_lseg_list(struct list_head *free_me)
730 {
731 	struct pnfs_layout_segment *lseg, *tmp;
732 
733 	if (list_empty(free_me))
734 		return;
735 
736 	list_for_each_entry_safe(lseg, tmp, free_me, pls_list) {
737 		list_del(&lseg->pls_list);
738 		pnfs_free_lseg(lseg);
739 	}
740 }
741 
742 static struct pnfs_layout_hdr *__pnfs_destroy_layout(struct nfs_inode *nfsi)
743 {
744 	struct pnfs_layout_hdr *lo;
745 	LIST_HEAD(tmp_list);
746 
747 	spin_lock(&nfsi->vfs_inode.i_lock);
748 	lo = nfsi->layout;
749 	if (lo) {
750 		pnfs_get_layout_hdr(lo);
751 		pnfs_mark_layout_stateid_invalid(lo, &tmp_list);
752 		pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RO_FAILED);
753 		pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RW_FAILED);
754 		spin_unlock(&nfsi->vfs_inode.i_lock);
755 		pnfs_free_lseg_list(&tmp_list);
756 		nfs_commit_inode(&nfsi->vfs_inode, 0);
757 		pnfs_put_layout_hdr(lo);
758 	} else
759 		spin_unlock(&nfsi->vfs_inode.i_lock);
760 	return lo;
761 }
762 
763 void pnfs_destroy_layout(struct nfs_inode *nfsi)
764 {
765 	__pnfs_destroy_layout(nfsi);
766 }
767 EXPORT_SYMBOL_GPL(pnfs_destroy_layout);
768 
769 static bool pnfs_layout_removed(struct nfs_inode *nfsi,
770 				struct pnfs_layout_hdr *lo)
771 {
772 	bool ret;
773 
774 	spin_lock(&nfsi->vfs_inode.i_lock);
775 	ret = nfsi->layout != lo;
776 	spin_unlock(&nfsi->vfs_inode.i_lock);
777 	return ret;
778 }
779 
780 void pnfs_destroy_layout_final(struct nfs_inode *nfsi)
781 {
782 	struct pnfs_layout_hdr *lo = __pnfs_destroy_layout(nfsi);
783 
784 	if (lo)
785 		wait_var_event(lo, pnfs_layout_removed(nfsi, lo));
786 }
787 
788 static bool
789 pnfs_layout_add_bulk_destroy_list(struct inode *inode,
790 		struct list_head *layout_list)
791 {
792 	struct pnfs_layout_hdr *lo;
793 	bool ret = false;
794 
795 	spin_lock(&inode->i_lock);
796 	lo = NFS_I(inode)->layout;
797 	if (lo != NULL && list_empty(&lo->plh_bulk_destroy)) {
798 		pnfs_get_layout_hdr(lo);
799 		list_add(&lo->plh_bulk_destroy, layout_list);
800 		ret = true;
801 	}
802 	spin_unlock(&inode->i_lock);
803 	return ret;
804 }
805 
806 /* Caller must hold rcu_read_lock and clp->cl_lock */
807 static int
808 pnfs_layout_bulk_destroy_byserver_locked(struct nfs_client *clp,
809 		struct nfs_server *server,
810 		struct list_head *layout_list)
811 	__must_hold(&clp->cl_lock)
812 	__must_hold(RCU)
813 {
814 	struct pnfs_layout_hdr *lo, *next;
815 	struct inode *inode;
816 
817 	list_for_each_entry_safe(lo, next, &server->layouts, plh_layouts) {
818 		if (test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags) ||
819 		    test_bit(NFS_LAYOUT_INODE_FREEING, &lo->plh_flags) ||
820 		    !list_empty(&lo->plh_bulk_destroy))
821 			continue;
822 		/* If the sb is being destroyed, just bail */
823 		if (!nfs_sb_active(server->super))
824 			break;
825 		inode = pnfs_grab_inode_layout_hdr(lo);
826 		if (inode != NULL) {
827 			if (test_and_clear_bit(NFS_LAYOUT_HASHED, &lo->plh_flags))
828 				list_del_rcu(&lo->plh_layouts);
829 			if (pnfs_layout_add_bulk_destroy_list(inode,
830 						layout_list))
831 				continue;
832 			rcu_read_unlock();
833 			spin_unlock(&clp->cl_lock);
834 			iput(inode);
835 		} else {
836 			rcu_read_unlock();
837 			spin_unlock(&clp->cl_lock);
838 		}
839 		nfs_sb_deactive(server->super);
840 		spin_lock(&clp->cl_lock);
841 		rcu_read_lock();
842 		return -EAGAIN;
843 	}
844 	return 0;
845 }
846 
847 static int
848 pnfs_layout_free_bulk_destroy_list(struct list_head *layout_list,
849 		bool is_bulk_recall)
850 {
851 	struct pnfs_layout_hdr *lo;
852 	struct inode *inode;
853 	LIST_HEAD(lseg_list);
854 	int ret = 0;
855 
856 	while (!list_empty(layout_list)) {
857 		lo = list_entry(layout_list->next, struct pnfs_layout_hdr,
858 				plh_bulk_destroy);
859 		dprintk("%s freeing layout for inode %lu\n", __func__,
860 			lo->plh_inode->i_ino);
861 		inode = lo->plh_inode;
862 
863 		pnfs_layoutcommit_inode(inode, false);
864 
865 		spin_lock(&inode->i_lock);
866 		list_del_init(&lo->plh_bulk_destroy);
867 		if (pnfs_mark_layout_stateid_invalid(lo, &lseg_list)) {
868 			if (is_bulk_recall)
869 				set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
870 			ret = -EAGAIN;
871 		}
872 		spin_unlock(&inode->i_lock);
873 		pnfs_free_lseg_list(&lseg_list);
874 		/* Free all lsegs that are attached to commit buckets */
875 		nfs_commit_inode(inode, 0);
876 		pnfs_put_layout_hdr(lo);
877 		nfs_iput_and_deactive(inode);
878 	}
879 	return ret;
880 }
881 
882 int
883 pnfs_destroy_layouts_byfsid(struct nfs_client *clp,
884 		struct nfs_fsid *fsid,
885 		bool is_recall)
886 {
887 	struct nfs_server *server;
888 	LIST_HEAD(layout_list);
889 
890 	spin_lock(&clp->cl_lock);
891 	rcu_read_lock();
892 restart:
893 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
894 		if (memcmp(&server->fsid, fsid, sizeof(*fsid)) != 0)
895 			continue;
896 		if (pnfs_layout_bulk_destroy_byserver_locked(clp,
897 				server,
898 				&layout_list) != 0)
899 			goto restart;
900 	}
901 	rcu_read_unlock();
902 	spin_unlock(&clp->cl_lock);
903 
904 	if (list_empty(&layout_list))
905 		return 0;
906 	return pnfs_layout_free_bulk_destroy_list(&layout_list, is_recall);
907 }
908 
909 int
910 pnfs_destroy_layouts_byclid(struct nfs_client *clp,
911 		bool is_recall)
912 {
913 	struct nfs_server *server;
914 	LIST_HEAD(layout_list);
915 
916 	spin_lock(&clp->cl_lock);
917 	rcu_read_lock();
918 restart:
919 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
920 		if (pnfs_layout_bulk_destroy_byserver_locked(clp,
921 					server,
922 					&layout_list) != 0)
923 			goto restart;
924 	}
925 	rcu_read_unlock();
926 	spin_unlock(&clp->cl_lock);
927 
928 	if (list_empty(&layout_list))
929 		return 0;
930 	return pnfs_layout_free_bulk_destroy_list(&layout_list, is_recall);
931 }
932 
933 /*
934  * Called by the state manager to remove all layouts established under an
935  * expired lease.
936  */
937 void
938 pnfs_destroy_all_layouts(struct nfs_client *clp)
939 {
940 	nfs4_deviceid_mark_client_invalid(clp);
941 	nfs4_deviceid_purge_client(clp);
942 
943 	pnfs_destroy_layouts_byclid(clp, false);
944 }
945 
946 static void
947 pnfs_set_layout_cred(struct pnfs_layout_hdr *lo, const struct cred *cred)
948 {
949 	const struct cred *old;
950 
951 	if (cred && cred_fscmp(lo->plh_lc_cred, cred) != 0) {
952 		old = xchg(&lo->plh_lc_cred, get_cred(cred));
953 		put_cred(old);
954 	}
955 }
956 
957 /* update lo->plh_stateid with new if is more recent */
958 void
959 pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
960 			const struct cred *cred, bool update_barrier)
961 {
962 	u32 oldseq, newseq, new_barrier = 0;
963 
964 	oldseq = be32_to_cpu(lo->plh_stateid.seqid);
965 	newseq = be32_to_cpu(new->seqid);
966 
967 	if (!pnfs_layout_is_valid(lo)) {
968 		pnfs_set_layout_cred(lo, cred);
969 		nfs4_stateid_copy(&lo->plh_stateid, new);
970 		lo->plh_barrier = newseq;
971 		pnfs_clear_layoutreturn_info(lo);
972 		clear_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
973 		return;
974 	}
975 	if (pnfs_seqid_is_newer(newseq, oldseq)) {
976 		nfs4_stateid_copy(&lo->plh_stateid, new);
977 		/*
978 		 * Because of wraparound, we want to keep the barrier
979 		 * "close" to the current seqids.
980 		 */
981 		new_barrier = newseq - atomic_read(&lo->plh_outstanding);
982 	}
983 	if (update_barrier)
984 		new_barrier = be32_to_cpu(new->seqid);
985 	else if (new_barrier == 0)
986 		return;
987 	if (pnfs_seqid_is_newer(new_barrier, lo->plh_barrier))
988 		lo->plh_barrier = new_barrier;
989 }
990 
991 static bool
992 pnfs_layout_stateid_blocked(const struct pnfs_layout_hdr *lo,
993 		const nfs4_stateid *stateid)
994 {
995 	u32 seqid = be32_to_cpu(stateid->seqid);
996 
997 	return !pnfs_seqid_is_newer(seqid, lo->plh_barrier);
998 }
999 
1000 /* lget is set to 1 if called from inside send_layoutget call chain */
1001 static bool
1002 pnfs_layoutgets_blocked(const struct pnfs_layout_hdr *lo)
1003 {
1004 	return lo->plh_block_lgets ||
1005 		test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
1006 }
1007 
1008 static struct nfs_server *
1009 pnfs_find_server(struct inode *inode, struct nfs_open_context *ctx)
1010 {
1011 	struct nfs_server *server;
1012 
1013 	if (inode) {
1014 		server = NFS_SERVER(inode);
1015 	} else {
1016 		struct dentry *parent_dir = dget_parent(ctx->dentry);
1017 		server = NFS_SERVER(parent_dir->d_inode);
1018 		dput(parent_dir);
1019 	}
1020 	return server;
1021 }
1022 
1023 static void nfs4_free_pages(struct page **pages, size_t size)
1024 {
1025 	int i;
1026 
1027 	if (!pages)
1028 		return;
1029 
1030 	for (i = 0; i < size; i++) {
1031 		if (!pages[i])
1032 			break;
1033 		__free_page(pages[i]);
1034 	}
1035 	kfree(pages);
1036 }
1037 
1038 static struct page **nfs4_alloc_pages(size_t size, gfp_t gfp_flags)
1039 {
1040 	struct page **pages;
1041 	int i;
1042 
1043 	pages = kmalloc_array(size, sizeof(struct page *), gfp_flags);
1044 	if (!pages) {
1045 		dprintk("%s: can't alloc array of %zu pages\n", __func__, size);
1046 		return NULL;
1047 	}
1048 
1049 	for (i = 0; i < size; i++) {
1050 		pages[i] = alloc_page(gfp_flags);
1051 		if (!pages[i]) {
1052 			dprintk("%s: failed to allocate page\n", __func__);
1053 			nfs4_free_pages(pages, i);
1054 			return NULL;
1055 		}
1056 	}
1057 
1058 	return pages;
1059 }
1060 
1061 static struct nfs4_layoutget *
1062 pnfs_alloc_init_layoutget_args(struct inode *ino,
1063 	   struct nfs_open_context *ctx,
1064 	   const nfs4_stateid *stateid,
1065 	   const struct pnfs_layout_range *range,
1066 	   gfp_t gfp_flags)
1067 {
1068 	struct nfs_server *server = pnfs_find_server(ino, ctx);
1069 	size_t max_reply_sz = server->pnfs_curr_ld->max_layoutget_response;
1070 	size_t max_pages = max_response_pages(server);
1071 	struct nfs4_layoutget *lgp;
1072 
1073 	dprintk("--> %s\n", __func__);
1074 
1075 	lgp = kzalloc(sizeof(*lgp), gfp_flags);
1076 	if (lgp == NULL)
1077 		return NULL;
1078 
1079 	if (max_reply_sz) {
1080 		size_t npages = (max_reply_sz + PAGE_SIZE - 1) >> PAGE_SHIFT;
1081 		if (npages < max_pages)
1082 			max_pages = npages;
1083 	}
1084 
1085 	lgp->args.layout.pages = nfs4_alloc_pages(max_pages, gfp_flags);
1086 	if (!lgp->args.layout.pages) {
1087 		kfree(lgp);
1088 		return NULL;
1089 	}
1090 	lgp->args.layout.pglen = max_pages * PAGE_SIZE;
1091 	lgp->res.layoutp = &lgp->args.layout;
1092 
1093 	/* Don't confuse uninitialised result and success */
1094 	lgp->res.status = -NFS4ERR_DELAY;
1095 
1096 	lgp->args.minlength = PAGE_SIZE;
1097 	if (lgp->args.minlength > range->length)
1098 		lgp->args.minlength = range->length;
1099 	if (ino) {
1100 		loff_t i_size = i_size_read(ino);
1101 
1102 		if (range->iomode == IOMODE_READ) {
1103 			if (range->offset >= i_size)
1104 				lgp->args.minlength = 0;
1105 			else if (i_size - range->offset < lgp->args.minlength)
1106 				lgp->args.minlength = i_size - range->offset;
1107 		}
1108 	}
1109 	lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
1110 	pnfs_copy_range(&lgp->args.range, range);
1111 	lgp->args.type = server->pnfs_curr_ld->id;
1112 	lgp->args.inode = ino;
1113 	lgp->args.ctx = get_nfs_open_context(ctx);
1114 	nfs4_stateid_copy(&lgp->args.stateid, stateid);
1115 	lgp->gfp_flags = gfp_flags;
1116 	lgp->cred = ctx->cred;
1117 	return lgp;
1118 }
1119 
1120 void pnfs_layoutget_free(struct nfs4_layoutget *lgp)
1121 {
1122 	size_t max_pages = lgp->args.layout.pglen / PAGE_SIZE;
1123 
1124 	nfs4_free_pages(lgp->args.layout.pages, max_pages);
1125 	if (lgp->args.inode)
1126 		pnfs_put_layout_hdr(NFS_I(lgp->args.inode)->layout);
1127 	put_nfs_open_context(lgp->args.ctx);
1128 	kfree(lgp);
1129 }
1130 
1131 static void pnfs_clear_layoutcommit(struct inode *inode,
1132 		struct list_head *head)
1133 {
1134 	struct nfs_inode *nfsi = NFS_I(inode);
1135 	struct pnfs_layout_segment *lseg, *tmp;
1136 
1137 	if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
1138 		return;
1139 	list_for_each_entry_safe(lseg, tmp, &nfsi->layout->plh_segs, pls_list) {
1140 		if (!test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
1141 			continue;
1142 		pnfs_lseg_dec_and_remove_zero(lseg, head);
1143 	}
1144 }
1145 
1146 void pnfs_layoutreturn_free_lsegs(struct pnfs_layout_hdr *lo,
1147 		const nfs4_stateid *arg_stateid,
1148 		const struct pnfs_layout_range *range,
1149 		const nfs4_stateid *stateid)
1150 {
1151 	struct inode *inode = lo->plh_inode;
1152 	LIST_HEAD(freeme);
1153 
1154 	spin_lock(&inode->i_lock);
1155 	if (!pnfs_layout_is_valid(lo) || !arg_stateid ||
1156 	    !nfs4_stateid_match_other(&lo->plh_stateid, arg_stateid))
1157 		goto out_unlock;
1158 	if (stateid) {
1159 		u32 seq = be32_to_cpu(arg_stateid->seqid);
1160 
1161 		pnfs_mark_matching_lsegs_invalid(lo, &freeme, range, seq);
1162 		pnfs_free_returned_lsegs(lo, &freeme, range, seq);
1163 		pnfs_set_layout_stateid(lo, stateid, NULL, true);
1164 	} else
1165 		pnfs_mark_layout_stateid_invalid(lo, &freeme);
1166 out_unlock:
1167 	pnfs_clear_layoutreturn_waitbit(lo);
1168 	spin_unlock(&inode->i_lock);
1169 	pnfs_free_lseg_list(&freeme);
1170 
1171 }
1172 
1173 static bool
1174 pnfs_prepare_layoutreturn(struct pnfs_layout_hdr *lo,
1175 		nfs4_stateid *stateid,
1176 		const struct cred **cred,
1177 		enum pnfs_iomode *iomode)
1178 {
1179 	/* Serialise LAYOUTGET/LAYOUTRETURN */
1180 	if (atomic_read(&lo->plh_outstanding) != 0)
1181 		return false;
1182 	if (test_and_set_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags))
1183 		return false;
1184 	set_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);
1185 	pnfs_get_layout_hdr(lo);
1186 	if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags)) {
1187 		nfs4_stateid_copy(stateid, &lo->plh_stateid);
1188 		*cred = get_cred(lo->plh_lc_cred);
1189 		if (lo->plh_return_seq != 0)
1190 			stateid->seqid = cpu_to_be32(lo->plh_return_seq);
1191 		if (iomode != NULL)
1192 			*iomode = lo->plh_return_iomode;
1193 		pnfs_clear_layoutreturn_info(lo);
1194 		return true;
1195 	}
1196 	nfs4_stateid_copy(stateid, &lo->plh_stateid);
1197 	*cred = get_cred(lo->plh_lc_cred);
1198 	if (iomode != NULL)
1199 		*iomode = IOMODE_ANY;
1200 	return true;
1201 }
1202 
1203 static void
1204 pnfs_init_layoutreturn_args(struct nfs4_layoutreturn_args *args,
1205 		struct pnfs_layout_hdr *lo,
1206 		const nfs4_stateid *stateid,
1207 		enum pnfs_iomode iomode)
1208 {
1209 	struct inode *inode = lo->plh_inode;
1210 
1211 	args->layout_type = NFS_SERVER(inode)->pnfs_curr_ld->id;
1212 	args->inode = inode;
1213 	args->range.iomode = iomode;
1214 	args->range.offset = 0;
1215 	args->range.length = NFS4_MAX_UINT64;
1216 	args->layout = lo;
1217 	nfs4_stateid_copy(&args->stateid, stateid);
1218 }
1219 
1220 static int
1221 pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo,
1222 		       const nfs4_stateid *stateid,
1223 		       const struct cred **pcred,
1224 		       enum pnfs_iomode iomode,
1225 		       bool sync)
1226 {
1227 	struct inode *ino = lo->plh_inode;
1228 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
1229 	struct nfs4_layoutreturn *lrp;
1230 	const struct cred *cred = *pcred;
1231 	int status = 0;
1232 
1233 	*pcred = NULL;
1234 	lrp = kzalloc(sizeof(*lrp), GFP_NOFS);
1235 	if (unlikely(lrp == NULL)) {
1236 		status = -ENOMEM;
1237 		spin_lock(&ino->i_lock);
1238 		pnfs_clear_layoutreturn_waitbit(lo);
1239 		spin_unlock(&ino->i_lock);
1240 		put_cred(cred);
1241 		pnfs_put_layout_hdr(lo);
1242 		goto out;
1243 	}
1244 
1245 	pnfs_init_layoutreturn_args(&lrp->args, lo, stateid, iomode);
1246 	lrp->args.ld_private = &lrp->ld_private;
1247 	lrp->clp = NFS_SERVER(ino)->nfs_client;
1248 	lrp->cred = cred;
1249 	if (ld->prepare_layoutreturn)
1250 		ld->prepare_layoutreturn(&lrp->args);
1251 
1252 	status = nfs4_proc_layoutreturn(lrp, sync);
1253 out:
1254 	dprintk("<-- %s status: %d\n", __func__, status);
1255 	return status;
1256 }
1257 
1258 static bool
1259 pnfs_layout_segments_returnable(struct pnfs_layout_hdr *lo,
1260 				enum pnfs_iomode iomode,
1261 				u32 seq)
1262 {
1263 	struct pnfs_layout_range recall_range = {
1264 		.length = NFS4_MAX_UINT64,
1265 		.iomode = iomode,
1266 	};
1267 	return pnfs_mark_matching_lsegs_return(lo, &lo->plh_return_segs,
1268 					       &recall_range, seq) != -EBUSY;
1269 }
1270 
1271 /* Return true if layoutreturn is needed */
1272 static bool
1273 pnfs_layout_need_return(struct pnfs_layout_hdr *lo)
1274 {
1275 	if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
1276 		return false;
1277 	return pnfs_layout_segments_returnable(lo, lo->plh_return_iomode,
1278 					       lo->plh_return_seq);
1279 }
1280 
1281 static void pnfs_layoutreturn_before_put_layout_hdr(struct pnfs_layout_hdr *lo)
1282 {
1283 	struct inode *inode= lo->plh_inode;
1284 
1285 	if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
1286 		return;
1287 	spin_lock(&inode->i_lock);
1288 	if (pnfs_layout_need_return(lo)) {
1289 		const struct cred *cred;
1290 		nfs4_stateid stateid;
1291 		enum pnfs_iomode iomode;
1292 		bool send;
1293 
1294 		send = pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode);
1295 		spin_unlock(&inode->i_lock);
1296 		if (send) {
1297 			/* Send an async layoutreturn so we dont deadlock */
1298 			pnfs_send_layoutreturn(lo, &stateid, &cred, iomode, false);
1299 		}
1300 	} else
1301 		spin_unlock(&inode->i_lock);
1302 }
1303 
1304 /*
1305  * Initiates a LAYOUTRETURN(FILE), and removes the pnfs_layout_hdr
1306  * when the layout segment list is empty.
1307  *
1308  * Note that a pnfs_layout_hdr can exist with an empty layout segment
1309  * list when LAYOUTGET has failed, or when LAYOUTGET succeeded, but the
1310  * deviceid is marked invalid.
1311  */
1312 int
1313 _pnfs_return_layout(struct inode *ino)
1314 {
1315 	struct pnfs_layout_hdr *lo = NULL;
1316 	struct nfs_inode *nfsi = NFS_I(ino);
1317 	LIST_HEAD(tmp_list);
1318 	const struct cred *cred;
1319 	nfs4_stateid stateid;
1320 	int status = 0;
1321 	bool send, valid_layout;
1322 
1323 	dprintk("NFS: %s for inode %lu\n", __func__, ino->i_ino);
1324 
1325 	spin_lock(&ino->i_lock);
1326 	lo = nfsi->layout;
1327 	if (!lo) {
1328 		spin_unlock(&ino->i_lock);
1329 		dprintk("NFS: %s no layout to return\n", __func__);
1330 		goto out;
1331 	}
1332 	/* Reference matched in nfs4_layoutreturn_release */
1333 	pnfs_get_layout_hdr(lo);
1334 	/* Is there an outstanding layoutreturn ? */
1335 	if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
1336 		spin_unlock(&ino->i_lock);
1337 		if (wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
1338 					TASK_UNINTERRUPTIBLE))
1339 			goto out_put_layout_hdr;
1340 		spin_lock(&ino->i_lock);
1341 	}
1342 	valid_layout = pnfs_layout_is_valid(lo);
1343 	pnfs_clear_layoutcommit(ino, &tmp_list);
1344 	pnfs_mark_matching_lsegs_invalid(lo, &tmp_list, NULL, 0);
1345 
1346 	if (NFS_SERVER(ino)->pnfs_curr_ld->return_range) {
1347 		struct pnfs_layout_range range = {
1348 			.iomode		= IOMODE_ANY,
1349 			.offset		= 0,
1350 			.length		= NFS4_MAX_UINT64,
1351 		};
1352 		NFS_SERVER(ino)->pnfs_curr_ld->return_range(lo, &range);
1353 	}
1354 
1355 	/* Don't send a LAYOUTRETURN if list was initially empty */
1356 	if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags) ||
1357 			!valid_layout) {
1358 		spin_unlock(&ino->i_lock);
1359 		dprintk("NFS: %s no layout segments to return\n", __func__);
1360 		goto out_wait_layoutreturn;
1361 	}
1362 
1363 	send = pnfs_prepare_layoutreturn(lo, &stateid, &cred, NULL);
1364 	spin_unlock(&ino->i_lock);
1365 	if (send)
1366 		status = pnfs_send_layoutreturn(lo, &stateid, &cred, IOMODE_ANY, true);
1367 out_wait_layoutreturn:
1368 	wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN, TASK_UNINTERRUPTIBLE);
1369 out_put_layout_hdr:
1370 	pnfs_free_lseg_list(&tmp_list);
1371 	pnfs_put_layout_hdr(lo);
1372 out:
1373 	dprintk("<-- %s status: %d\n", __func__, status);
1374 	return status;
1375 }
1376 
1377 int
1378 pnfs_commit_and_return_layout(struct inode *inode)
1379 {
1380 	struct pnfs_layout_hdr *lo;
1381 	int ret;
1382 
1383 	spin_lock(&inode->i_lock);
1384 	lo = NFS_I(inode)->layout;
1385 	if (lo == NULL) {
1386 		spin_unlock(&inode->i_lock);
1387 		return 0;
1388 	}
1389 	pnfs_get_layout_hdr(lo);
1390 	/* Block new layoutgets and read/write to ds */
1391 	lo->plh_block_lgets++;
1392 	spin_unlock(&inode->i_lock);
1393 	filemap_fdatawait(inode->i_mapping);
1394 	ret = pnfs_layoutcommit_inode(inode, true);
1395 	if (ret == 0)
1396 		ret = _pnfs_return_layout(inode);
1397 	spin_lock(&inode->i_lock);
1398 	lo->plh_block_lgets--;
1399 	spin_unlock(&inode->i_lock);
1400 	pnfs_put_layout_hdr(lo);
1401 	return ret;
1402 }
1403 
1404 bool pnfs_roc(struct inode *ino,
1405 		struct nfs4_layoutreturn_args *args,
1406 		struct nfs4_layoutreturn_res *res,
1407 		const struct cred *cred)
1408 {
1409 	struct nfs_inode *nfsi = NFS_I(ino);
1410 	struct nfs_open_context *ctx;
1411 	struct nfs4_state *state;
1412 	struct pnfs_layout_hdr *lo;
1413 	struct pnfs_layout_segment *lseg, *next;
1414 	const struct cred *lc_cred;
1415 	nfs4_stateid stateid;
1416 	enum pnfs_iomode iomode = 0;
1417 	bool layoutreturn = false, roc = false;
1418 	bool skip_read = false;
1419 
1420 	if (!nfs_have_layout(ino))
1421 		return false;
1422 retry:
1423 	rcu_read_lock();
1424 	spin_lock(&ino->i_lock);
1425 	lo = nfsi->layout;
1426 	if (!lo || !pnfs_layout_is_valid(lo) ||
1427 	    test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1428 		lo = NULL;
1429 		goto out_noroc;
1430 	}
1431 	pnfs_get_layout_hdr(lo);
1432 	if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
1433 		spin_unlock(&ino->i_lock);
1434 		rcu_read_unlock();
1435 		wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
1436 				TASK_UNINTERRUPTIBLE);
1437 		pnfs_put_layout_hdr(lo);
1438 		goto retry;
1439 	}
1440 
1441 	/* no roc if we hold a delegation */
1442 	if (nfs4_check_delegation(ino, FMODE_READ)) {
1443 		if (nfs4_check_delegation(ino, FMODE_WRITE))
1444 			goto out_noroc;
1445 		skip_read = true;
1446 	}
1447 
1448 	list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
1449 		state = ctx->state;
1450 		if (state == NULL)
1451 			continue;
1452 		/* Don't return layout if there is open file state */
1453 		if (state->state & FMODE_WRITE)
1454 			goto out_noroc;
1455 		if (state->state & FMODE_READ)
1456 			skip_read = true;
1457 	}
1458 
1459 
1460 	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list) {
1461 		if (skip_read && lseg->pls_range.iomode == IOMODE_READ)
1462 			continue;
1463 		/* If we are sending layoutreturn, invalidate all valid lsegs */
1464 		if (!test_and_clear_bit(NFS_LSEG_ROC, &lseg->pls_flags))
1465 			continue;
1466 		/*
1467 		 * Note: mark lseg for return so pnfs_layout_remove_lseg
1468 		 * doesn't invalidate the layout for us.
1469 		 */
1470 		set_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
1471 		if (!mark_lseg_invalid(lseg, &lo->plh_return_segs))
1472 			continue;
1473 		pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
1474 	}
1475 
1476 	if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
1477 		goto out_noroc;
1478 
1479 	/* ROC in two conditions:
1480 	 * 1. there are ROC lsegs
1481 	 * 2. we don't send layoutreturn
1482 	 */
1483 	/* lo ref dropped in pnfs_roc_release() */
1484 	layoutreturn = pnfs_prepare_layoutreturn(lo, &stateid, &lc_cred, &iomode);
1485 	/* If the creds don't match, we can't compound the layoutreturn */
1486 	if (!layoutreturn || cred_fscmp(cred, lc_cred) != 0)
1487 		goto out_noroc;
1488 
1489 	roc = layoutreturn;
1490 	pnfs_init_layoutreturn_args(args, lo, &stateid, iomode);
1491 	res->lrs_present = 0;
1492 	layoutreturn = false;
1493 	put_cred(lc_cred);
1494 
1495 out_noroc:
1496 	spin_unlock(&ino->i_lock);
1497 	rcu_read_unlock();
1498 	pnfs_layoutcommit_inode(ino, true);
1499 	if (roc) {
1500 		struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
1501 		if (ld->prepare_layoutreturn)
1502 			ld->prepare_layoutreturn(args);
1503 		pnfs_put_layout_hdr(lo);
1504 		return true;
1505 	}
1506 	if (layoutreturn)
1507 		pnfs_send_layoutreturn(lo, &stateid, &lc_cred, iomode, true);
1508 	pnfs_put_layout_hdr(lo);
1509 	return false;
1510 }
1511 
1512 int pnfs_roc_done(struct rpc_task *task, struct inode *inode,
1513 		struct nfs4_layoutreturn_args **argpp,
1514 		struct nfs4_layoutreturn_res **respp,
1515 		int *ret)
1516 {
1517 	struct nfs4_layoutreturn_args *arg = *argpp;
1518 	int retval = -EAGAIN;
1519 
1520 	if (!arg)
1521 		return 0;
1522 	/* Handle Layoutreturn errors */
1523 	switch (*ret) {
1524 	case 0:
1525 		retval = 0;
1526 		break;
1527 	case -NFS4ERR_NOMATCHING_LAYOUT:
1528 		/* Was there an RPC level error? If not, retry */
1529 		if (task->tk_rpc_status == 0)
1530 			break;
1531 		/* If the call was not sent, let caller handle it */
1532 		if (!RPC_WAS_SENT(task))
1533 			return 0;
1534 		/*
1535 		 * Otherwise, assume the call succeeded and
1536 		 * that we need to release the layout
1537 		 */
1538 		*ret = 0;
1539 		(*respp)->lrs_present = 0;
1540 		retval = 0;
1541 		break;
1542 	case -NFS4ERR_DELAY:
1543 		/* Let the caller handle the retry */
1544 		*ret = -NFS4ERR_NOMATCHING_LAYOUT;
1545 		return 0;
1546 	case -NFS4ERR_OLD_STATEID:
1547 		if (!nfs4_layout_refresh_old_stateid(&arg->stateid,
1548 					&arg->range, inode))
1549 			break;
1550 		*ret = -NFS4ERR_NOMATCHING_LAYOUT;
1551 		return -EAGAIN;
1552 	}
1553 	*argpp = NULL;
1554 	*respp = NULL;
1555 	return retval;
1556 }
1557 
1558 void pnfs_roc_release(struct nfs4_layoutreturn_args *args,
1559 		struct nfs4_layoutreturn_res *res,
1560 		int ret)
1561 {
1562 	struct pnfs_layout_hdr *lo = args->layout;
1563 	const nfs4_stateid *arg_stateid = NULL;
1564 	const nfs4_stateid *res_stateid = NULL;
1565 	struct nfs4_xdr_opaque_data *ld_private = args->ld_private;
1566 
1567 	switch (ret) {
1568 	case -NFS4ERR_NOMATCHING_LAYOUT:
1569 		break;
1570 	case 0:
1571 		if (res->lrs_present)
1572 			res_stateid = &res->stateid;
1573 		fallthrough;
1574 	default:
1575 		arg_stateid = &args->stateid;
1576 	}
1577 	trace_nfs4_layoutreturn_on_close(args->inode, &args->stateid, ret);
1578 	pnfs_layoutreturn_free_lsegs(lo, arg_stateid, &args->range,
1579 			res_stateid);
1580 	if (ld_private && ld_private->ops && ld_private->ops->free)
1581 		ld_private->ops->free(ld_private);
1582 	pnfs_put_layout_hdr(lo);
1583 }
1584 
1585 bool pnfs_wait_on_layoutreturn(struct inode *ino, struct rpc_task *task)
1586 {
1587 	struct nfs_inode *nfsi = NFS_I(ino);
1588         struct pnfs_layout_hdr *lo;
1589         bool sleep = false;
1590 
1591 	/* we might not have grabbed lo reference. so need to check under
1592 	 * i_lock */
1593         spin_lock(&ino->i_lock);
1594         lo = nfsi->layout;
1595         if (lo && test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
1596                 rpc_sleep_on(&NFS_SERVER(ino)->roc_rpcwaitq, task, NULL);
1597                 sleep = true;
1598 	}
1599         spin_unlock(&ino->i_lock);
1600         return sleep;
1601 }
1602 
1603 /*
1604  * Compare two layout segments for sorting into layout cache.
1605  * We want to preferentially return RW over RO layouts, so ensure those
1606  * are seen first.
1607  */
1608 static s64
1609 pnfs_lseg_range_cmp(const struct pnfs_layout_range *l1,
1610 	   const struct pnfs_layout_range *l2)
1611 {
1612 	s64 d;
1613 
1614 	/* high offset > low offset */
1615 	d = l1->offset - l2->offset;
1616 	if (d)
1617 		return d;
1618 
1619 	/* short length > long length */
1620 	d = l2->length - l1->length;
1621 	if (d)
1622 		return d;
1623 
1624 	/* read > read/write */
1625 	return (int)(l1->iomode == IOMODE_READ) - (int)(l2->iomode == IOMODE_READ);
1626 }
1627 
1628 static bool
1629 pnfs_lseg_range_is_after(const struct pnfs_layout_range *l1,
1630 		const struct pnfs_layout_range *l2)
1631 {
1632 	return pnfs_lseg_range_cmp(l1, l2) > 0;
1633 }
1634 
1635 static bool
1636 pnfs_lseg_no_merge(struct pnfs_layout_segment *lseg,
1637 		struct pnfs_layout_segment *old)
1638 {
1639 	return false;
1640 }
1641 
1642 void
1643 pnfs_generic_layout_insert_lseg(struct pnfs_layout_hdr *lo,
1644 		   struct pnfs_layout_segment *lseg,
1645 		   bool (*is_after)(const struct pnfs_layout_range *,
1646 			   const struct pnfs_layout_range *),
1647 		   bool (*do_merge)(struct pnfs_layout_segment *,
1648 			   struct pnfs_layout_segment *),
1649 		   struct list_head *free_me)
1650 {
1651 	struct pnfs_layout_segment *lp, *tmp;
1652 
1653 	dprintk("%s:Begin\n", __func__);
1654 
1655 	list_for_each_entry_safe(lp, tmp, &lo->plh_segs, pls_list) {
1656 		if (test_bit(NFS_LSEG_VALID, &lp->pls_flags) == 0)
1657 			continue;
1658 		if (do_merge(lseg, lp)) {
1659 			mark_lseg_invalid(lp, free_me);
1660 			continue;
1661 		}
1662 		if (is_after(&lseg->pls_range, &lp->pls_range))
1663 			continue;
1664 		list_add_tail(&lseg->pls_list, &lp->pls_list);
1665 		dprintk("%s: inserted lseg %p "
1666 			"iomode %d offset %llu length %llu before "
1667 			"lp %p iomode %d offset %llu length %llu\n",
1668 			__func__, lseg, lseg->pls_range.iomode,
1669 			lseg->pls_range.offset, lseg->pls_range.length,
1670 			lp, lp->pls_range.iomode, lp->pls_range.offset,
1671 			lp->pls_range.length);
1672 		goto out;
1673 	}
1674 	list_add_tail(&lseg->pls_list, &lo->plh_segs);
1675 	dprintk("%s: inserted lseg %p "
1676 		"iomode %d offset %llu length %llu at tail\n",
1677 		__func__, lseg, lseg->pls_range.iomode,
1678 		lseg->pls_range.offset, lseg->pls_range.length);
1679 out:
1680 	pnfs_get_layout_hdr(lo);
1681 
1682 	dprintk("%s:Return\n", __func__);
1683 }
1684 EXPORT_SYMBOL_GPL(pnfs_generic_layout_insert_lseg);
1685 
1686 static void
1687 pnfs_layout_insert_lseg(struct pnfs_layout_hdr *lo,
1688 		   struct pnfs_layout_segment *lseg,
1689 		   struct list_head *free_me)
1690 {
1691 	struct inode *inode = lo->plh_inode;
1692 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
1693 
1694 	if (ld->add_lseg != NULL)
1695 		ld->add_lseg(lo, lseg, free_me);
1696 	else
1697 		pnfs_generic_layout_insert_lseg(lo, lseg,
1698 				pnfs_lseg_range_is_after,
1699 				pnfs_lseg_no_merge,
1700 				free_me);
1701 }
1702 
1703 static struct pnfs_layout_hdr *
1704 alloc_init_layout_hdr(struct inode *ino,
1705 		      struct nfs_open_context *ctx,
1706 		      gfp_t gfp_flags)
1707 {
1708 	struct pnfs_layout_hdr *lo;
1709 
1710 	lo = pnfs_alloc_layout_hdr(ino, gfp_flags);
1711 	if (!lo)
1712 		return NULL;
1713 	refcount_set(&lo->plh_refcount, 1);
1714 	INIT_LIST_HEAD(&lo->plh_layouts);
1715 	INIT_LIST_HEAD(&lo->plh_segs);
1716 	INIT_LIST_HEAD(&lo->plh_return_segs);
1717 	INIT_LIST_HEAD(&lo->plh_bulk_destroy);
1718 	lo->plh_inode = ino;
1719 	lo->plh_lc_cred = get_cred(ctx->cred);
1720 	lo->plh_flags |= 1 << NFS_LAYOUT_INVALID_STID;
1721 	return lo;
1722 }
1723 
1724 static struct pnfs_layout_hdr *
1725 pnfs_find_alloc_layout(struct inode *ino,
1726 		       struct nfs_open_context *ctx,
1727 		       gfp_t gfp_flags)
1728 	__releases(&ino->i_lock)
1729 	__acquires(&ino->i_lock)
1730 {
1731 	struct nfs_inode *nfsi = NFS_I(ino);
1732 	struct pnfs_layout_hdr *new = NULL;
1733 
1734 	dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);
1735 
1736 	if (nfsi->layout != NULL)
1737 		goto out_existing;
1738 	spin_unlock(&ino->i_lock);
1739 	new = alloc_init_layout_hdr(ino, ctx, gfp_flags);
1740 	spin_lock(&ino->i_lock);
1741 
1742 	if (likely(nfsi->layout == NULL)) {	/* Won the race? */
1743 		nfsi->layout = new;
1744 		return new;
1745 	} else if (new != NULL)
1746 		pnfs_free_layout_hdr(new);
1747 out_existing:
1748 	pnfs_get_layout_hdr(nfsi->layout);
1749 	return nfsi->layout;
1750 }
1751 
1752 /*
1753  * iomode matching rules:
1754  * iomode	lseg	strict match
1755  *                      iomode
1756  * -----	-----	------ -----
1757  * ANY		READ	N/A    true
1758  * ANY		RW	N/A    true
1759  * RW		READ	N/A    false
1760  * RW		RW	N/A    true
1761  * READ		READ	N/A    true
1762  * READ		RW	true   false
1763  * READ		RW	false  true
1764  */
1765 static bool
1766 pnfs_lseg_range_match(const struct pnfs_layout_range *ls_range,
1767 		 const struct pnfs_layout_range *range,
1768 		 bool strict_iomode)
1769 {
1770 	struct pnfs_layout_range range1;
1771 
1772 	if ((range->iomode == IOMODE_RW &&
1773 	     ls_range->iomode != IOMODE_RW) ||
1774 	    (range->iomode != ls_range->iomode &&
1775 	     strict_iomode) ||
1776 	    !pnfs_lseg_range_intersecting(ls_range, range))
1777 		return false;
1778 
1779 	/* range1 covers only the first byte in the range */
1780 	range1 = *range;
1781 	range1.length = 1;
1782 	return pnfs_lseg_range_contained(ls_range, &range1);
1783 }
1784 
1785 /*
1786  * lookup range in layout
1787  */
1788 static struct pnfs_layout_segment *
1789 pnfs_find_lseg(struct pnfs_layout_hdr *lo,
1790 		struct pnfs_layout_range *range,
1791 		bool strict_iomode)
1792 {
1793 	struct pnfs_layout_segment *lseg, *ret = NULL;
1794 
1795 	dprintk("%s:Begin\n", __func__);
1796 
1797 	list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
1798 		if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
1799 		    pnfs_lseg_range_match(&lseg->pls_range, range,
1800 					  strict_iomode)) {
1801 			ret = pnfs_get_lseg(lseg);
1802 			break;
1803 		}
1804 	}
1805 
1806 	dprintk("%s:Return lseg %p ref %d\n",
1807 		__func__, ret, ret ? refcount_read(&ret->pls_refcount) : 0);
1808 	return ret;
1809 }
1810 
1811 /*
1812  * Use mdsthreshold hints set at each OPEN to determine if I/O should go
1813  * to the MDS or over pNFS
1814  *
1815  * The nfs_inode read_io and write_io fields are cumulative counters reset
1816  * when there are no layout segments. Note that in pnfs_update_layout iomode
1817  * is set to IOMODE_READ for a READ request, and set to IOMODE_RW for a
1818  * WRITE request.
1819  *
1820  * A return of true means use MDS I/O.
1821  *
1822  * From rfc 5661:
1823  * If a file's size is smaller than the file size threshold, data accesses
1824  * SHOULD be sent to the metadata server.  If an I/O request has a length that
1825  * is below the I/O size threshold, the I/O SHOULD be sent to the metadata
1826  * server.  If both file size and I/O size are provided, the client SHOULD
1827  * reach or exceed  both thresholds before sending its read or write
1828  * requests to the data server.
1829  */
1830 static bool pnfs_within_mdsthreshold(struct nfs_open_context *ctx,
1831 				     struct inode *ino, int iomode)
1832 {
1833 	struct nfs4_threshold *t = ctx->mdsthreshold;
1834 	struct nfs_inode *nfsi = NFS_I(ino);
1835 	loff_t fsize = i_size_read(ino);
1836 	bool size = false, size_set = false, io = false, io_set = false, ret = false;
1837 
1838 	if (t == NULL)
1839 		return ret;
1840 
1841 	dprintk("%s bm=0x%x rd_sz=%llu wr_sz=%llu rd_io=%llu wr_io=%llu\n",
1842 		__func__, t->bm, t->rd_sz, t->wr_sz, t->rd_io_sz, t->wr_io_sz);
1843 
1844 	switch (iomode) {
1845 	case IOMODE_READ:
1846 		if (t->bm & THRESHOLD_RD) {
1847 			dprintk("%s fsize %llu\n", __func__, fsize);
1848 			size_set = true;
1849 			if (fsize < t->rd_sz)
1850 				size = true;
1851 		}
1852 		if (t->bm & THRESHOLD_RD_IO) {
1853 			dprintk("%s nfsi->read_io %llu\n", __func__,
1854 				nfsi->read_io);
1855 			io_set = true;
1856 			if (nfsi->read_io < t->rd_io_sz)
1857 				io = true;
1858 		}
1859 		break;
1860 	case IOMODE_RW:
1861 		if (t->bm & THRESHOLD_WR) {
1862 			dprintk("%s fsize %llu\n", __func__, fsize);
1863 			size_set = true;
1864 			if (fsize < t->wr_sz)
1865 				size = true;
1866 		}
1867 		if (t->bm & THRESHOLD_WR_IO) {
1868 			dprintk("%s nfsi->write_io %llu\n", __func__,
1869 				nfsi->write_io);
1870 			io_set = true;
1871 			if (nfsi->write_io < t->wr_io_sz)
1872 				io = true;
1873 		}
1874 		break;
1875 	}
1876 	if (size_set && io_set) {
1877 		if (size && io)
1878 			ret = true;
1879 	} else if (size || io)
1880 		ret = true;
1881 
1882 	dprintk("<-- %s size %d io %d ret %d\n", __func__, size, io, ret);
1883 	return ret;
1884 }
1885 
1886 static int pnfs_prepare_to_retry_layoutget(struct pnfs_layout_hdr *lo)
1887 {
1888 	/*
1889 	 * send layoutcommit as it can hold up layoutreturn due to lseg
1890 	 * reference
1891 	 */
1892 	pnfs_layoutcommit_inode(lo->plh_inode, false);
1893 	return wait_on_bit_action(&lo->plh_flags, NFS_LAYOUT_RETURN,
1894 				   nfs_wait_bit_killable,
1895 				   TASK_KILLABLE);
1896 }
1897 
1898 static void nfs_layoutget_begin(struct pnfs_layout_hdr *lo)
1899 {
1900 	atomic_inc(&lo->plh_outstanding);
1901 }
1902 
1903 static void nfs_layoutget_end(struct pnfs_layout_hdr *lo)
1904 {
1905 	if (atomic_dec_and_test(&lo->plh_outstanding))
1906 		wake_up_var(&lo->plh_outstanding);
1907 }
1908 
1909 static void pnfs_clear_first_layoutget(struct pnfs_layout_hdr *lo)
1910 {
1911 	unsigned long *bitlock = &lo->plh_flags;
1912 
1913 	clear_bit_unlock(NFS_LAYOUT_FIRST_LAYOUTGET, bitlock);
1914 	smp_mb__after_atomic();
1915 	wake_up_bit(bitlock, NFS_LAYOUT_FIRST_LAYOUTGET);
1916 }
1917 
1918 static void _add_to_server_list(struct pnfs_layout_hdr *lo,
1919 				struct nfs_server *server)
1920 {
1921 	if (!test_and_set_bit(NFS_LAYOUT_HASHED, &lo->plh_flags)) {
1922 		struct nfs_client *clp = server->nfs_client;
1923 
1924 		/* The lo must be on the clp list if there is any
1925 		 * chance of a CB_LAYOUTRECALL(FILE) coming in.
1926 		 */
1927 		spin_lock(&clp->cl_lock);
1928 		list_add_tail_rcu(&lo->plh_layouts, &server->layouts);
1929 		spin_unlock(&clp->cl_lock);
1930 	}
1931 }
1932 
1933 /*
1934  * Layout segment is retreived from the server if not cached.
1935  * The appropriate layout segment is referenced and returned to the caller.
1936  */
1937 struct pnfs_layout_segment *
1938 pnfs_update_layout(struct inode *ino,
1939 		   struct nfs_open_context *ctx,
1940 		   loff_t pos,
1941 		   u64 count,
1942 		   enum pnfs_iomode iomode,
1943 		   bool strict_iomode,
1944 		   gfp_t gfp_flags)
1945 {
1946 	struct pnfs_layout_range arg = {
1947 		.iomode = iomode,
1948 		.offset = pos,
1949 		.length = count,
1950 	};
1951 	unsigned pg_offset;
1952 	struct nfs_server *server = NFS_SERVER(ino);
1953 	struct nfs_client *clp = server->nfs_client;
1954 	struct pnfs_layout_hdr *lo = NULL;
1955 	struct pnfs_layout_segment *lseg = NULL;
1956 	struct nfs4_layoutget *lgp;
1957 	nfs4_stateid stateid;
1958 	long timeout = 0;
1959 	unsigned long giveup = jiffies + (clp->cl_lease_time << 1);
1960 	bool first;
1961 
1962 	if (!pnfs_enabled_sb(NFS_SERVER(ino))) {
1963 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
1964 				 PNFS_UPDATE_LAYOUT_NO_PNFS);
1965 		goto out;
1966 	}
1967 
1968 	if (pnfs_within_mdsthreshold(ctx, ino, iomode)) {
1969 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
1970 				 PNFS_UPDATE_LAYOUT_MDSTHRESH);
1971 		goto out;
1972 	}
1973 
1974 lookup_again:
1975 	lseg = ERR_PTR(nfs4_client_recover_expired_lease(clp));
1976 	if (IS_ERR(lseg))
1977 		goto out;
1978 	first = false;
1979 	spin_lock(&ino->i_lock);
1980 	lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
1981 	if (lo == NULL) {
1982 		spin_unlock(&ino->i_lock);
1983 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
1984 				 PNFS_UPDATE_LAYOUT_NOMEM);
1985 		goto out;
1986 	}
1987 
1988 	/* Do we even need to bother with this? */
1989 	if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1990 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
1991 				 PNFS_UPDATE_LAYOUT_BULK_RECALL);
1992 		dprintk("%s matches recall, use MDS\n", __func__);
1993 		goto out_unlock;
1994 	}
1995 
1996 	/* if LAYOUTGET already failed once we don't try again */
1997 	if (pnfs_layout_io_test_failed(lo, iomode)) {
1998 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
1999 				 PNFS_UPDATE_LAYOUT_IO_TEST_FAIL);
2000 		goto out_unlock;
2001 	}
2002 
2003 	/*
2004 	 * If the layout segment list is empty, but there are outstanding
2005 	 * layoutget calls, then they might be subject to a layoutrecall.
2006 	 */
2007 	if (list_empty(&lo->plh_segs) &&
2008 	    atomic_read(&lo->plh_outstanding) != 0) {
2009 		spin_unlock(&ino->i_lock);
2010 		lseg = ERR_PTR(wait_var_event_killable(&lo->plh_outstanding,
2011 					!atomic_read(&lo->plh_outstanding)));
2012 		if (IS_ERR(lseg))
2013 			goto out_put_layout_hdr;
2014 		pnfs_put_layout_hdr(lo);
2015 		goto lookup_again;
2016 	}
2017 
2018 	lseg = pnfs_find_lseg(lo, &arg, strict_iomode);
2019 	if (lseg) {
2020 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2021 				PNFS_UPDATE_LAYOUT_FOUND_CACHED);
2022 		goto out_unlock;
2023 	}
2024 
2025 	/*
2026 	 * Choose a stateid for the LAYOUTGET. If we don't have a layout
2027 	 * stateid, or it has been invalidated, then we must use the open
2028 	 * stateid.
2029 	 */
2030 	if (test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags)) {
2031 		int status;
2032 
2033 		/*
2034 		 * The first layoutget for the file. Need to serialize per
2035 		 * RFC 5661 Errata 3208.
2036 		 */
2037 		if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET,
2038 				     &lo->plh_flags)) {
2039 			spin_unlock(&ino->i_lock);
2040 			lseg = ERR_PTR(wait_on_bit(&lo->plh_flags,
2041 						NFS_LAYOUT_FIRST_LAYOUTGET,
2042 						TASK_KILLABLE));
2043 			if (IS_ERR(lseg))
2044 				goto out_put_layout_hdr;
2045 			pnfs_put_layout_hdr(lo);
2046 			dprintk("%s retrying\n", __func__);
2047 			goto lookup_again;
2048 		}
2049 
2050 		spin_unlock(&ino->i_lock);
2051 		first = true;
2052 		status = nfs4_select_rw_stateid(ctx->state,
2053 					iomode == IOMODE_RW ? FMODE_WRITE : FMODE_READ,
2054 					NULL, &stateid, NULL);
2055 		if (status != 0) {
2056 			lseg = ERR_PTR(status);
2057 			trace_pnfs_update_layout(ino, pos, count,
2058 					iomode, lo, lseg,
2059 					PNFS_UPDATE_LAYOUT_INVALID_OPEN);
2060 			nfs4_schedule_stateid_recovery(server, ctx->state);
2061 			pnfs_clear_first_layoutget(lo);
2062 			pnfs_put_layout_hdr(lo);
2063 			goto lookup_again;
2064 		}
2065 		spin_lock(&ino->i_lock);
2066 	} else {
2067 		nfs4_stateid_copy(&stateid, &lo->plh_stateid);
2068 	}
2069 
2070 	/*
2071 	 * Because we free lsegs before sending LAYOUTRETURN, we need to wait
2072 	 * for LAYOUTRETURN even if first is true.
2073 	 */
2074 	if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
2075 		spin_unlock(&ino->i_lock);
2076 		dprintk("%s wait for layoutreturn\n", __func__);
2077 		lseg = ERR_PTR(pnfs_prepare_to_retry_layoutget(lo));
2078 		if (!IS_ERR(lseg)) {
2079 			if (first)
2080 				pnfs_clear_first_layoutget(lo);
2081 			pnfs_put_layout_hdr(lo);
2082 			dprintk("%s retrying\n", __func__);
2083 			trace_pnfs_update_layout(ino, pos, count, iomode, lo,
2084 					lseg, PNFS_UPDATE_LAYOUT_RETRY);
2085 			goto lookup_again;
2086 		}
2087 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2088 				PNFS_UPDATE_LAYOUT_RETURN);
2089 		goto out_put_layout_hdr;
2090 	}
2091 
2092 	if (pnfs_layoutgets_blocked(lo)) {
2093 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2094 				PNFS_UPDATE_LAYOUT_BLOCKED);
2095 		goto out_unlock;
2096 	}
2097 	nfs_layoutget_begin(lo);
2098 	spin_unlock(&ino->i_lock);
2099 
2100 	_add_to_server_list(lo, server);
2101 
2102 	pg_offset = arg.offset & ~PAGE_MASK;
2103 	if (pg_offset) {
2104 		arg.offset -= pg_offset;
2105 		arg.length += pg_offset;
2106 	}
2107 	if (arg.length != NFS4_MAX_UINT64)
2108 		arg.length = PAGE_ALIGN(arg.length);
2109 
2110 	lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &stateid, &arg, gfp_flags);
2111 	if (!lgp) {
2112 		trace_pnfs_update_layout(ino, pos, count, iomode, lo, NULL,
2113 					 PNFS_UPDATE_LAYOUT_NOMEM);
2114 		nfs_layoutget_end(lo);
2115 		goto out_put_layout_hdr;
2116 	}
2117 
2118 	lseg = nfs4_proc_layoutget(lgp, &timeout);
2119 	trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2120 				 PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET);
2121 	nfs_layoutget_end(lo);
2122 	if (IS_ERR(lseg)) {
2123 		switch(PTR_ERR(lseg)) {
2124 		case -EBUSY:
2125 			if (time_after(jiffies, giveup))
2126 				lseg = NULL;
2127 			break;
2128 		case -ERECALLCONFLICT:
2129 		case -EAGAIN:
2130 			break;
2131 		default:
2132 			if (!nfs_error_is_fatal(PTR_ERR(lseg))) {
2133 				pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
2134 				lseg = NULL;
2135 			}
2136 			goto out_put_layout_hdr;
2137 		}
2138 		if (lseg) {
2139 			if (first)
2140 				pnfs_clear_first_layoutget(lo);
2141 			trace_pnfs_update_layout(ino, pos, count,
2142 				iomode, lo, lseg, PNFS_UPDATE_LAYOUT_RETRY);
2143 			pnfs_put_layout_hdr(lo);
2144 			goto lookup_again;
2145 		}
2146 	} else {
2147 		pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
2148 	}
2149 
2150 out_put_layout_hdr:
2151 	if (first)
2152 		pnfs_clear_first_layoutget(lo);
2153 	trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
2154 				 PNFS_UPDATE_LAYOUT_EXIT);
2155 	pnfs_put_layout_hdr(lo);
2156 out:
2157 	dprintk("%s: inode %s/%llu pNFS layout segment %s for "
2158 			"(%s, offset: %llu, length: %llu)\n",
2159 			__func__, ino->i_sb->s_id,
2160 			(unsigned long long)NFS_FILEID(ino),
2161 			IS_ERR_OR_NULL(lseg) ? "not found" : "found",
2162 			iomode==IOMODE_RW ?  "read/write" : "read-only",
2163 			(unsigned long long)pos,
2164 			(unsigned long long)count);
2165 	return lseg;
2166 out_unlock:
2167 	spin_unlock(&ino->i_lock);
2168 	goto out_put_layout_hdr;
2169 }
2170 EXPORT_SYMBOL_GPL(pnfs_update_layout);
2171 
2172 static bool
2173 pnfs_sanity_check_layout_range(struct pnfs_layout_range *range)
2174 {
2175 	switch (range->iomode) {
2176 	case IOMODE_READ:
2177 	case IOMODE_RW:
2178 		break;
2179 	default:
2180 		return false;
2181 	}
2182 	if (range->offset == NFS4_MAX_UINT64)
2183 		return false;
2184 	if (range->length == 0)
2185 		return false;
2186 	if (range->length != NFS4_MAX_UINT64 &&
2187 	    range->length > NFS4_MAX_UINT64 - range->offset)
2188 		return false;
2189 	return true;
2190 }
2191 
2192 static struct pnfs_layout_hdr *
2193 _pnfs_grab_empty_layout(struct inode *ino, struct nfs_open_context *ctx)
2194 {
2195 	struct pnfs_layout_hdr *lo;
2196 
2197 	spin_lock(&ino->i_lock);
2198 	lo = pnfs_find_alloc_layout(ino, ctx, GFP_KERNEL);
2199 	if (!lo)
2200 		goto out_unlock;
2201 	if (!test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags))
2202 		goto out_unlock;
2203 	if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags))
2204 		goto out_unlock;
2205 	if (pnfs_layoutgets_blocked(lo))
2206 		goto out_unlock;
2207 	if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET, &lo->plh_flags))
2208 		goto out_unlock;
2209 	nfs_layoutget_begin(lo);
2210 	spin_unlock(&ino->i_lock);
2211 	_add_to_server_list(lo, NFS_SERVER(ino));
2212 	return lo;
2213 
2214 out_unlock:
2215 	spin_unlock(&ino->i_lock);
2216 	pnfs_put_layout_hdr(lo);
2217 	return NULL;
2218 }
2219 
2220 static void _lgopen_prepare_attached(struct nfs4_opendata *data,
2221 				     struct nfs_open_context *ctx)
2222 {
2223 	struct inode *ino = data->dentry->d_inode;
2224 	struct pnfs_layout_range rng = {
2225 		.iomode = (data->o_arg.fmode & FMODE_WRITE) ?
2226 			  IOMODE_RW: IOMODE_READ,
2227 		.offset = 0,
2228 		.length = NFS4_MAX_UINT64,
2229 	};
2230 	struct nfs4_layoutget *lgp;
2231 	struct pnfs_layout_hdr *lo;
2232 
2233 	/* Heuristic: don't send layoutget if we have cached data */
2234 	if (rng.iomode == IOMODE_READ &&
2235 	   (i_size_read(ino) == 0 || ino->i_mapping->nrpages != 0))
2236 		return;
2237 
2238 	lo = _pnfs_grab_empty_layout(ino, ctx);
2239 	if (!lo)
2240 		return;
2241 	lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &current_stateid,
2242 					     &rng, GFP_KERNEL);
2243 	if (!lgp) {
2244 		pnfs_clear_first_layoutget(lo);
2245 		pnfs_put_layout_hdr(lo);
2246 		return;
2247 	}
2248 	data->lgp = lgp;
2249 	data->o_arg.lg_args = &lgp->args;
2250 	data->o_res.lg_res = &lgp->res;
2251 }
2252 
2253 static void _lgopen_prepare_floating(struct nfs4_opendata *data,
2254 				     struct nfs_open_context *ctx)
2255 {
2256 	struct pnfs_layout_range rng = {
2257 		.iomode = (data->o_arg.fmode & FMODE_WRITE) ?
2258 			  IOMODE_RW: IOMODE_READ,
2259 		.offset = 0,
2260 		.length = NFS4_MAX_UINT64,
2261 	};
2262 	struct nfs4_layoutget *lgp;
2263 
2264 	lgp = pnfs_alloc_init_layoutget_args(NULL, ctx, &current_stateid,
2265 					     &rng, GFP_KERNEL);
2266 	if (!lgp)
2267 		return;
2268 	data->lgp = lgp;
2269 	data->o_arg.lg_args = &lgp->args;
2270 	data->o_res.lg_res = &lgp->res;
2271 }
2272 
2273 void pnfs_lgopen_prepare(struct nfs4_opendata *data,
2274 			 struct nfs_open_context *ctx)
2275 {
2276 	struct nfs_server *server = NFS_SERVER(data->dir->d_inode);
2277 
2278 	if (!(pnfs_enabled_sb(server) &&
2279 	      server->pnfs_curr_ld->flags & PNFS_LAYOUTGET_ON_OPEN))
2280 		return;
2281 	/* Could check on max_ops, but currently hardcoded high enough */
2282 	if (!nfs_server_capable(data->dir->d_inode, NFS_CAP_LGOPEN))
2283 		return;
2284 	if (data->state)
2285 		_lgopen_prepare_attached(data, ctx);
2286 	else
2287 		_lgopen_prepare_floating(data, ctx);
2288 }
2289 
2290 void pnfs_parse_lgopen(struct inode *ino, struct nfs4_layoutget *lgp,
2291 		       struct nfs_open_context *ctx)
2292 {
2293 	struct pnfs_layout_hdr *lo;
2294 	struct pnfs_layout_segment *lseg;
2295 	struct nfs_server *srv = NFS_SERVER(ino);
2296 	u32 iomode;
2297 
2298 	if (!lgp)
2299 		return;
2300 	dprintk("%s: entered with status %i\n", __func__, lgp->res.status);
2301 	if (lgp->res.status) {
2302 		switch (lgp->res.status) {
2303 		default:
2304 			break;
2305 		/*
2306 		 * Halt lgopen attempts if the server doesn't recognise
2307 		 * the "current stateid" value, the layout type, or the
2308 		 * layoutget operation as being valid.
2309 		 * Also if it complains about too many ops in the compound
2310 		 * or of the request/reply being too big.
2311 		 */
2312 		case -NFS4ERR_BAD_STATEID:
2313 		case -NFS4ERR_NOTSUPP:
2314 		case -NFS4ERR_REP_TOO_BIG:
2315 		case -NFS4ERR_REP_TOO_BIG_TO_CACHE:
2316 		case -NFS4ERR_REQ_TOO_BIG:
2317 		case -NFS4ERR_TOO_MANY_OPS:
2318 		case -NFS4ERR_UNKNOWN_LAYOUTTYPE:
2319 			srv->caps &= ~NFS_CAP_LGOPEN;
2320 		}
2321 		return;
2322 	}
2323 	if (!lgp->args.inode) {
2324 		lo = _pnfs_grab_empty_layout(ino, ctx);
2325 		if (!lo)
2326 			return;
2327 		lgp->args.inode = ino;
2328 	} else
2329 		lo = NFS_I(lgp->args.inode)->layout;
2330 
2331 	lseg = pnfs_layout_process(lgp);
2332 	if (!IS_ERR(lseg)) {
2333 		iomode = lgp->args.range.iomode;
2334 		pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
2335 		pnfs_put_lseg(lseg);
2336 	}
2337 }
2338 
2339 void nfs4_lgopen_release(struct nfs4_layoutget *lgp)
2340 {
2341 	if (lgp != NULL) {
2342 		struct inode *inode = lgp->args.inode;
2343 		if (inode) {
2344 			struct pnfs_layout_hdr *lo = NFS_I(inode)->layout;
2345 			pnfs_clear_first_layoutget(lo);
2346 			nfs_layoutget_end(lo);
2347 		}
2348 		pnfs_layoutget_free(lgp);
2349 	}
2350 }
2351 
2352 struct pnfs_layout_segment *
2353 pnfs_layout_process(struct nfs4_layoutget *lgp)
2354 {
2355 	struct pnfs_layout_hdr *lo = NFS_I(lgp->args.inode)->layout;
2356 	struct nfs4_layoutget_res *res = &lgp->res;
2357 	struct pnfs_layout_segment *lseg;
2358 	struct inode *ino = lo->plh_inode;
2359 	LIST_HEAD(free_me);
2360 
2361 	if (!pnfs_sanity_check_layout_range(&res->range))
2362 		return ERR_PTR(-EINVAL);
2363 
2364 	/* Inject layout blob into I/O device driver */
2365 	lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res, lgp->gfp_flags);
2366 	if (IS_ERR_OR_NULL(lseg)) {
2367 		if (!lseg)
2368 			lseg = ERR_PTR(-ENOMEM);
2369 
2370 		dprintk("%s: Could not allocate layout: error %ld\n",
2371 		       __func__, PTR_ERR(lseg));
2372 		return lseg;
2373 	}
2374 
2375 	pnfs_init_lseg(lo, lseg, &res->range, &res->stateid);
2376 
2377 	spin_lock(&ino->i_lock);
2378 	if (pnfs_layoutgets_blocked(lo)) {
2379 		dprintk("%s forget reply due to state\n", __func__);
2380 		goto out_forget;
2381 	}
2382 
2383 	if (!pnfs_layout_is_valid(lo)) {
2384 		/* We have a completely new layout */
2385 		pnfs_set_layout_stateid(lo, &res->stateid, lgp->cred, true);
2386 	} else if (nfs4_stateid_match_other(&lo->plh_stateid, &res->stateid)) {
2387 		/* existing state ID, make sure the sequence number matches. */
2388 		if (pnfs_layout_stateid_blocked(lo, &res->stateid)) {
2389 			dprintk("%s forget reply due to sequence\n", __func__);
2390 			goto out_forget;
2391 		}
2392 		pnfs_set_layout_stateid(lo, &res->stateid, lgp->cred, false);
2393 	} else {
2394 		/*
2395 		 * We got an entirely new state ID.  Mark all segments for the
2396 		 * inode invalid, and retry the layoutget
2397 		 */
2398 		pnfs_mark_layout_stateid_invalid(lo, &free_me);
2399 		goto out_forget;
2400 	}
2401 
2402 	pnfs_get_lseg(lseg);
2403 	pnfs_layout_insert_lseg(lo, lseg, &free_me);
2404 
2405 
2406 	if (res->return_on_close)
2407 		set_bit(NFS_LSEG_ROC, &lseg->pls_flags);
2408 
2409 	spin_unlock(&ino->i_lock);
2410 	pnfs_free_lseg_list(&free_me);
2411 	return lseg;
2412 
2413 out_forget:
2414 	spin_unlock(&ino->i_lock);
2415 	lseg->pls_layout = lo;
2416 	NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
2417 	return ERR_PTR(-EAGAIN);
2418 }
2419 
2420 /**
2421  * pnfs_mark_matching_lsegs_return - Free or return matching layout segments
2422  * @lo: pointer to layout header
2423  * @tmp_list: list header to be used with pnfs_free_lseg_list()
2424  * @return_range: describe layout segment ranges to be returned
2425  * @seq: stateid seqid to match
2426  *
2427  * This function is mainly intended for use by layoutrecall. It attempts
2428  * to free the layout segment immediately, or else to mark it for return
2429  * as soon as its reference count drops to zero.
2430  *
2431  * Returns
2432  * - 0: a layoutreturn needs to be scheduled.
2433  * - EBUSY: there are layout segment that are still in use.
2434  * - ENOENT: there are no layout segments that need to be returned.
2435  */
2436 int
2437 pnfs_mark_matching_lsegs_return(struct pnfs_layout_hdr *lo,
2438 				struct list_head *tmp_list,
2439 				const struct pnfs_layout_range *return_range,
2440 				u32 seq)
2441 {
2442 	struct pnfs_layout_segment *lseg, *next;
2443 	int remaining = 0;
2444 
2445 	dprintk("%s:Begin lo %p\n", __func__, lo);
2446 
2447 	assert_spin_locked(&lo->plh_inode->i_lock);
2448 
2449 	list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
2450 		if (pnfs_match_lseg_recall(lseg, return_range, seq)) {
2451 			dprintk("%s: marking lseg %p iomode %d "
2452 				"offset %llu length %llu\n", __func__,
2453 				lseg, lseg->pls_range.iomode,
2454 				lseg->pls_range.offset,
2455 				lseg->pls_range.length);
2456 			if (mark_lseg_invalid(lseg, tmp_list))
2457 				continue;
2458 			remaining++;
2459 			set_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
2460 		}
2461 
2462 	if (remaining) {
2463 		pnfs_set_plh_return_info(lo, return_range->iomode, seq);
2464 		return -EBUSY;
2465 	}
2466 
2467 	if (!list_empty(&lo->plh_return_segs)) {
2468 		pnfs_set_plh_return_info(lo, return_range->iomode, seq);
2469 		return 0;
2470 	}
2471 
2472 	return -ENOENT;
2473 }
2474 
2475 static void
2476 pnfs_mark_layout_for_return(struct inode *inode,
2477 			    const struct pnfs_layout_range *range)
2478 {
2479 	struct pnfs_layout_hdr *lo;
2480 	bool return_now = false;
2481 
2482 	spin_lock(&inode->i_lock);
2483 	lo = NFS_I(inode)->layout;
2484 	if (!pnfs_layout_is_valid(lo)) {
2485 		spin_unlock(&inode->i_lock);
2486 		return;
2487 	}
2488 	pnfs_set_plh_return_info(lo, range->iomode, 0);
2489 	/*
2490 	 * mark all matching lsegs so that we are sure to have no live
2491 	 * segments at hand when sending layoutreturn. See pnfs_put_lseg()
2492 	 * for how it works.
2493 	 */
2494 	if (pnfs_mark_matching_lsegs_return(lo, &lo->plh_return_segs, range, 0) != -EBUSY) {
2495 		const struct cred *cred;
2496 		nfs4_stateid stateid;
2497 		enum pnfs_iomode iomode;
2498 
2499 		return_now = pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode);
2500 		spin_unlock(&inode->i_lock);
2501 		if (return_now)
2502 			pnfs_send_layoutreturn(lo, &stateid, &cred, iomode, false);
2503 	} else {
2504 		spin_unlock(&inode->i_lock);
2505 		nfs_commit_inode(inode, 0);
2506 	}
2507 }
2508 
2509 void pnfs_error_mark_layout_for_return(struct inode *inode,
2510 				       struct pnfs_layout_segment *lseg)
2511 {
2512 	struct pnfs_layout_range range = {
2513 		.iomode = lseg->pls_range.iomode,
2514 		.offset = 0,
2515 		.length = NFS4_MAX_UINT64,
2516 	};
2517 
2518 	pnfs_mark_layout_for_return(inode, &range);
2519 }
2520 EXPORT_SYMBOL_GPL(pnfs_error_mark_layout_for_return);
2521 
2522 static bool
2523 pnfs_layout_can_be_returned(struct pnfs_layout_hdr *lo)
2524 {
2525 	return pnfs_layout_is_valid(lo) &&
2526 		!test_bit(NFS_LAYOUT_INODE_FREEING, &lo->plh_flags) &&
2527 		!test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);
2528 }
2529 
2530 static struct pnfs_layout_segment *
2531 pnfs_find_first_lseg(struct pnfs_layout_hdr *lo,
2532 		     const struct pnfs_layout_range *range,
2533 		     enum pnfs_iomode iomode)
2534 {
2535 	struct pnfs_layout_segment *lseg;
2536 
2537 	list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
2538 		if (!test_bit(NFS_LSEG_VALID, &lseg->pls_flags))
2539 			continue;
2540 		if (test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
2541 			continue;
2542 		if (lseg->pls_range.iomode != iomode && iomode != IOMODE_ANY)
2543 			continue;
2544 		if (pnfs_lseg_range_intersecting(&lseg->pls_range, range))
2545 			return lseg;
2546 	}
2547 	return NULL;
2548 }
2549 
2550 /* Find open file states whose mode matches that of the range */
2551 static bool
2552 pnfs_should_return_unused_layout(struct pnfs_layout_hdr *lo,
2553 				 const struct pnfs_layout_range *range)
2554 {
2555 	struct list_head *head;
2556 	struct nfs_open_context *ctx;
2557 	fmode_t mode = 0;
2558 
2559 	if (!pnfs_layout_can_be_returned(lo) ||
2560 	    !pnfs_find_first_lseg(lo, range, range->iomode))
2561 		return false;
2562 
2563 	head = &NFS_I(lo->plh_inode)->open_files;
2564 	list_for_each_entry_rcu(ctx, head, list) {
2565 		if (ctx->state)
2566 			mode |= ctx->state->state & (FMODE_READ|FMODE_WRITE);
2567 	}
2568 
2569 	switch (range->iomode) {
2570 	default:
2571 		break;
2572 	case IOMODE_READ:
2573 		mode &= ~FMODE_WRITE;
2574 		break;
2575 	case IOMODE_RW:
2576 		if (pnfs_find_first_lseg(lo, range, IOMODE_READ))
2577 			mode &= ~FMODE_READ;
2578 	}
2579 	return mode == 0;
2580 }
2581 
2582 static int
2583 pnfs_layout_return_unused_byserver(struct nfs_server *server, void *data)
2584 {
2585 	const struct pnfs_layout_range *range = data;
2586 	struct pnfs_layout_hdr *lo;
2587 	struct inode *inode;
2588 restart:
2589 	rcu_read_lock();
2590 	list_for_each_entry_rcu(lo, &server->layouts, plh_layouts) {
2591 		if (!pnfs_layout_can_be_returned(lo) ||
2592 		    test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
2593 			continue;
2594 		inode = lo->plh_inode;
2595 		spin_lock(&inode->i_lock);
2596 		if (!pnfs_should_return_unused_layout(lo, range)) {
2597 			spin_unlock(&inode->i_lock);
2598 			continue;
2599 		}
2600 		spin_unlock(&inode->i_lock);
2601 		inode = pnfs_grab_inode_layout_hdr(lo);
2602 		if (!inode)
2603 			continue;
2604 		rcu_read_unlock();
2605 		pnfs_mark_layout_for_return(inode, range);
2606 		iput(inode);
2607 		cond_resched();
2608 		goto restart;
2609 	}
2610 	rcu_read_unlock();
2611 	return 0;
2612 }
2613 
2614 void
2615 pnfs_layout_return_unused_byclid(struct nfs_client *clp,
2616 				 enum pnfs_iomode iomode)
2617 {
2618 	struct pnfs_layout_range range = {
2619 		.iomode = iomode,
2620 		.offset = 0,
2621 		.length = NFS4_MAX_UINT64,
2622 	};
2623 
2624 	nfs_client_for_each_server(clp, pnfs_layout_return_unused_byserver,
2625 			&range);
2626 }
2627 
2628 void
2629 pnfs_generic_pg_check_layout(struct nfs_pageio_descriptor *pgio)
2630 {
2631 	if (pgio->pg_lseg == NULL ||
2632 	    test_bit(NFS_LSEG_VALID, &pgio->pg_lseg->pls_flags))
2633 		return;
2634 	pnfs_put_lseg(pgio->pg_lseg);
2635 	pgio->pg_lseg = NULL;
2636 }
2637 EXPORT_SYMBOL_GPL(pnfs_generic_pg_check_layout);
2638 
2639 /*
2640  * Check for any intersection between the request and the pgio->pg_lseg,
2641  * and if none, put this pgio->pg_lseg away.
2642  */
2643 void
2644 pnfs_generic_pg_check_range(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
2645 {
2646 	if (pgio->pg_lseg && !pnfs_lseg_request_intersecting(pgio->pg_lseg, req)) {
2647 		pnfs_put_lseg(pgio->pg_lseg);
2648 		pgio->pg_lseg = NULL;
2649 	}
2650 }
2651 EXPORT_SYMBOL_GPL(pnfs_generic_pg_check_range);
2652 
2653 void
2654 pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
2655 {
2656 	u64 rd_size = req->wb_bytes;
2657 
2658 	pnfs_generic_pg_check_layout(pgio);
2659 	pnfs_generic_pg_check_range(pgio, req);
2660 	if (pgio->pg_lseg == NULL) {
2661 		if (pgio->pg_dreq == NULL)
2662 			rd_size = i_size_read(pgio->pg_inode) - req_offset(req);
2663 		else
2664 			rd_size = nfs_dreq_bytes_left(pgio->pg_dreq);
2665 
2666 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
2667 						   nfs_req_openctx(req),
2668 						   req_offset(req),
2669 						   rd_size,
2670 						   IOMODE_READ,
2671 						   false,
2672 						   GFP_KERNEL);
2673 		if (IS_ERR(pgio->pg_lseg)) {
2674 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
2675 			pgio->pg_lseg = NULL;
2676 			return;
2677 		}
2678 	}
2679 	/* If no lseg, fall back to read through mds */
2680 	if (pgio->pg_lseg == NULL)
2681 		nfs_pageio_reset_read_mds(pgio);
2682 
2683 }
2684 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_read);
2685 
2686 void
2687 pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
2688 			   struct nfs_page *req, u64 wb_size)
2689 {
2690 	pnfs_generic_pg_check_layout(pgio);
2691 	pnfs_generic_pg_check_range(pgio, req);
2692 	if (pgio->pg_lseg == NULL) {
2693 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
2694 						   nfs_req_openctx(req),
2695 						   req_offset(req),
2696 						   wb_size,
2697 						   IOMODE_RW,
2698 						   false,
2699 						   GFP_KERNEL);
2700 		if (IS_ERR(pgio->pg_lseg)) {
2701 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
2702 			pgio->pg_lseg = NULL;
2703 			return;
2704 		}
2705 	}
2706 	/* If no lseg, fall back to write through mds */
2707 	if (pgio->pg_lseg == NULL)
2708 		nfs_pageio_reset_write_mds(pgio);
2709 }
2710 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
2711 
2712 void
2713 pnfs_generic_pg_cleanup(struct nfs_pageio_descriptor *desc)
2714 {
2715 	if (desc->pg_lseg) {
2716 		pnfs_put_lseg(desc->pg_lseg);
2717 		desc->pg_lseg = NULL;
2718 	}
2719 }
2720 EXPORT_SYMBOL_GPL(pnfs_generic_pg_cleanup);
2721 
2722 /*
2723  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
2724  * of bytes (maximum @req->wb_bytes) that can be coalesced.
2725  */
2726 size_t
2727 pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio,
2728 		     struct nfs_page *prev, struct nfs_page *req)
2729 {
2730 	unsigned int size;
2731 	u64 seg_end, req_start, seg_left;
2732 
2733 	size = nfs_generic_pg_test(pgio, prev, req);
2734 	if (!size)
2735 		return 0;
2736 
2737 	/*
2738 	 * 'size' contains the number of bytes left in the current page (up
2739 	 * to the original size asked for in @req->wb_bytes).
2740 	 *
2741 	 * Calculate how many bytes are left in the layout segment
2742 	 * and if there are less bytes than 'size', return that instead.
2743 	 *
2744 	 * Please also note that 'end_offset' is actually the offset of the
2745 	 * first byte that lies outside the pnfs_layout_range. FIXME?
2746 	 *
2747 	 */
2748 	if (pgio->pg_lseg) {
2749 		seg_end = pnfs_end_offset(pgio->pg_lseg->pls_range.offset,
2750 				     pgio->pg_lseg->pls_range.length);
2751 		req_start = req_offset(req);
2752 
2753 		/* start of request is past the last byte of this segment */
2754 		if (req_start >= seg_end)
2755 			return 0;
2756 
2757 		/* adjust 'size' iff there are fewer bytes left in the
2758 		 * segment than what nfs_generic_pg_test returned */
2759 		seg_left = seg_end - req_start;
2760 		if (seg_left < size)
2761 			size = (unsigned int)seg_left;
2762 	}
2763 
2764 	return size;
2765 }
2766 EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);
2767 
2768 int pnfs_write_done_resend_to_mds(struct nfs_pgio_header *hdr)
2769 {
2770 	struct nfs_pageio_descriptor pgio;
2771 
2772 	/* Resend all requests through the MDS */
2773 	nfs_pageio_init_write(&pgio, hdr->inode, FLUSH_STABLE, true,
2774 			      hdr->completion_ops);
2775 	set_bit(NFS_CONTEXT_RESEND_WRITES, &hdr->args.context->flags);
2776 	return nfs_pageio_resend(&pgio, hdr);
2777 }
2778 EXPORT_SYMBOL_GPL(pnfs_write_done_resend_to_mds);
2779 
2780 static void pnfs_ld_handle_write_error(struct nfs_pgio_header *hdr)
2781 {
2782 
2783 	dprintk("pnfs write error = %d\n", hdr->pnfs_error);
2784 	if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
2785 	    PNFS_LAYOUTRET_ON_ERROR) {
2786 		pnfs_return_layout(hdr->inode);
2787 	}
2788 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
2789 		hdr->task.tk_status = pnfs_write_done_resend_to_mds(hdr);
2790 }
2791 
2792 /*
2793  * Called by non rpc-based layout drivers
2794  */
2795 void pnfs_ld_write_done(struct nfs_pgio_header *hdr)
2796 {
2797 	if (likely(!hdr->pnfs_error)) {
2798 		pnfs_set_layoutcommit(hdr->inode, hdr->lseg,
2799 				hdr->mds_offset + hdr->res.count);
2800 		hdr->mds_ops->rpc_call_done(&hdr->task, hdr);
2801 	}
2802 	trace_nfs4_pnfs_write(hdr, hdr->pnfs_error);
2803 	if (unlikely(hdr->pnfs_error))
2804 		pnfs_ld_handle_write_error(hdr);
2805 	hdr->mds_ops->rpc_release(hdr);
2806 }
2807 EXPORT_SYMBOL_GPL(pnfs_ld_write_done);
2808 
2809 static void
2810 pnfs_write_through_mds(struct nfs_pageio_descriptor *desc,
2811 		struct nfs_pgio_header *hdr)
2812 {
2813 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
2814 
2815 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
2816 		list_splice_tail_init(&hdr->pages, &mirror->pg_list);
2817 		nfs_pageio_reset_write_mds(desc);
2818 		mirror->pg_recoalesce = 1;
2819 	}
2820 	hdr->completion_ops->completion(hdr);
2821 }
2822 
2823 static enum pnfs_try_status
2824 pnfs_try_to_write_data(struct nfs_pgio_header *hdr,
2825 			const struct rpc_call_ops *call_ops,
2826 			struct pnfs_layout_segment *lseg,
2827 			int how)
2828 {
2829 	struct inode *inode = hdr->inode;
2830 	enum pnfs_try_status trypnfs;
2831 	struct nfs_server *nfss = NFS_SERVER(inode);
2832 
2833 	hdr->mds_ops = call_ops;
2834 
2835 	dprintk("%s: Writing ino:%lu %u@%llu (how %d)\n", __func__,
2836 		inode->i_ino, hdr->args.count, hdr->args.offset, how);
2837 	trypnfs = nfss->pnfs_curr_ld->write_pagelist(hdr, how);
2838 	if (trypnfs != PNFS_NOT_ATTEMPTED)
2839 		nfs_inc_stats(inode, NFSIOS_PNFS_WRITE);
2840 	dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
2841 	return trypnfs;
2842 }
2843 
2844 static void
2845 pnfs_do_write(struct nfs_pageio_descriptor *desc,
2846 	      struct nfs_pgio_header *hdr, int how)
2847 {
2848 	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
2849 	struct pnfs_layout_segment *lseg = desc->pg_lseg;
2850 	enum pnfs_try_status trypnfs;
2851 
2852 	trypnfs = pnfs_try_to_write_data(hdr, call_ops, lseg, how);
2853 	switch (trypnfs) {
2854 	case PNFS_NOT_ATTEMPTED:
2855 		pnfs_write_through_mds(desc, hdr);
2856 	case PNFS_ATTEMPTED:
2857 		break;
2858 	case PNFS_TRY_AGAIN:
2859 		/* cleanup hdr and prepare to redo pnfs */
2860 		if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
2861 			struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
2862 			list_splice_init(&hdr->pages, &mirror->pg_list);
2863 			mirror->pg_recoalesce = 1;
2864 		}
2865 		hdr->mds_ops->rpc_release(hdr);
2866 	}
2867 }
2868 
2869 static void pnfs_writehdr_free(struct nfs_pgio_header *hdr)
2870 {
2871 	pnfs_put_lseg(hdr->lseg);
2872 	nfs_pgio_header_free(hdr);
2873 }
2874 
2875 int
2876 pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
2877 {
2878 	struct nfs_pgio_header *hdr;
2879 	int ret;
2880 
2881 	hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
2882 	if (!hdr) {
2883 		desc->pg_error = -ENOMEM;
2884 		return desc->pg_error;
2885 	}
2886 	nfs_pgheader_init(desc, hdr, pnfs_writehdr_free);
2887 
2888 	hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
2889 	ret = nfs_generic_pgio(desc, hdr);
2890 	if (!ret)
2891 		pnfs_do_write(desc, hdr, desc->pg_ioflags);
2892 
2893 	return ret;
2894 }
2895 EXPORT_SYMBOL_GPL(pnfs_generic_pg_writepages);
2896 
2897 int pnfs_read_done_resend_to_mds(struct nfs_pgio_header *hdr)
2898 {
2899 	struct nfs_pageio_descriptor pgio;
2900 
2901 	/* Resend all requests through the MDS */
2902 	nfs_pageio_init_read(&pgio, hdr->inode, true, hdr->completion_ops);
2903 	return nfs_pageio_resend(&pgio, hdr);
2904 }
2905 EXPORT_SYMBOL_GPL(pnfs_read_done_resend_to_mds);
2906 
2907 static void pnfs_ld_handle_read_error(struct nfs_pgio_header *hdr)
2908 {
2909 	dprintk("pnfs read error = %d\n", hdr->pnfs_error);
2910 	if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
2911 	    PNFS_LAYOUTRET_ON_ERROR) {
2912 		pnfs_return_layout(hdr->inode);
2913 	}
2914 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
2915 		hdr->task.tk_status = pnfs_read_done_resend_to_mds(hdr);
2916 }
2917 
2918 /*
2919  * Called by non rpc-based layout drivers
2920  */
2921 void pnfs_ld_read_done(struct nfs_pgio_header *hdr)
2922 {
2923 	if (likely(!hdr->pnfs_error))
2924 		hdr->mds_ops->rpc_call_done(&hdr->task, hdr);
2925 	trace_nfs4_pnfs_read(hdr, hdr->pnfs_error);
2926 	if (unlikely(hdr->pnfs_error))
2927 		pnfs_ld_handle_read_error(hdr);
2928 	hdr->mds_ops->rpc_release(hdr);
2929 }
2930 EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
2931 
2932 static void
2933 pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
2934 		struct nfs_pgio_header *hdr)
2935 {
2936 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
2937 
2938 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
2939 		list_splice_tail_init(&hdr->pages, &mirror->pg_list);
2940 		nfs_pageio_reset_read_mds(desc);
2941 		mirror->pg_recoalesce = 1;
2942 	}
2943 	hdr->completion_ops->completion(hdr);
2944 }
2945 
2946 /*
2947  * Call the appropriate parallel I/O subsystem read function.
2948  */
2949 static enum pnfs_try_status
2950 pnfs_try_to_read_data(struct nfs_pgio_header *hdr,
2951 		       const struct rpc_call_ops *call_ops,
2952 		       struct pnfs_layout_segment *lseg)
2953 {
2954 	struct inode *inode = hdr->inode;
2955 	struct nfs_server *nfss = NFS_SERVER(inode);
2956 	enum pnfs_try_status trypnfs;
2957 
2958 	hdr->mds_ops = call_ops;
2959 
2960 	dprintk("%s: Reading ino:%lu %u@%llu\n",
2961 		__func__, inode->i_ino, hdr->args.count, hdr->args.offset);
2962 
2963 	trypnfs = nfss->pnfs_curr_ld->read_pagelist(hdr);
2964 	if (trypnfs != PNFS_NOT_ATTEMPTED)
2965 		nfs_inc_stats(inode, NFSIOS_PNFS_READ);
2966 	dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
2967 	return trypnfs;
2968 }
2969 
2970 /* Resend all requests through pnfs. */
2971 void pnfs_read_resend_pnfs(struct nfs_pgio_header *hdr,
2972 			   unsigned int mirror_idx)
2973 {
2974 	struct nfs_pageio_descriptor pgio;
2975 
2976 	if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
2977 		/* Prevent deadlocks with layoutreturn! */
2978 		pnfs_put_lseg(hdr->lseg);
2979 		hdr->lseg = NULL;
2980 
2981 		nfs_pageio_init_read(&pgio, hdr->inode, false,
2982 					hdr->completion_ops);
2983 		pgio.pg_mirror_idx = mirror_idx;
2984 		hdr->task.tk_status = nfs_pageio_resend(&pgio, hdr);
2985 	}
2986 }
2987 EXPORT_SYMBOL_GPL(pnfs_read_resend_pnfs);
2988 
2989 static void
2990 pnfs_do_read(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr)
2991 {
2992 	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
2993 	struct pnfs_layout_segment *lseg = desc->pg_lseg;
2994 	enum pnfs_try_status trypnfs;
2995 
2996 	trypnfs = pnfs_try_to_read_data(hdr, call_ops, lseg);
2997 	switch (trypnfs) {
2998 	case PNFS_NOT_ATTEMPTED:
2999 		pnfs_read_through_mds(desc, hdr);
3000 	case PNFS_ATTEMPTED:
3001 		break;
3002 	case PNFS_TRY_AGAIN:
3003 		/* cleanup hdr and prepare to redo pnfs */
3004 		if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
3005 			struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
3006 			list_splice_init(&hdr->pages, &mirror->pg_list);
3007 			mirror->pg_recoalesce = 1;
3008 		}
3009 		hdr->mds_ops->rpc_release(hdr);
3010 	}
3011 }
3012 
3013 static void pnfs_readhdr_free(struct nfs_pgio_header *hdr)
3014 {
3015 	pnfs_put_lseg(hdr->lseg);
3016 	nfs_pgio_header_free(hdr);
3017 }
3018 
3019 int
3020 pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
3021 {
3022 	struct nfs_pgio_header *hdr;
3023 	int ret;
3024 
3025 	hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
3026 	if (!hdr) {
3027 		desc->pg_error = -ENOMEM;
3028 		return desc->pg_error;
3029 	}
3030 	nfs_pgheader_init(desc, hdr, pnfs_readhdr_free);
3031 	hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
3032 	ret = nfs_generic_pgio(desc, hdr);
3033 	if (!ret)
3034 		pnfs_do_read(desc, hdr);
3035 	return ret;
3036 }
3037 EXPORT_SYMBOL_GPL(pnfs_generic_pg_readpages);
3038 
3039 static void pnfs_clear_layoutcommitting(struct inode *inode)
3040 {
3041 	unsigned long *bitlock = &NFS_I(inode)->flags;
3042 
3043 	clear_bit_unlock(NFS_INO_LAYOUTCOMMITTING, bitlock);
3044 	smp_mb__after_atomic();
3045 	wake_up_bit(bitlock, NFS_INO_LAYOUTCOMMITTING);
3046 }
3047 
3048 /*
3049  * There can be multiple RW segments.
3050  */
3051 static void pnfs_list_write_lseg(struct inode *inode, struct list_head *listp)
3052 {
3053 	struct pnfs_layout_segment *lseg;
3054 
3055 	list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) {
3056 		if (lseg->pls_range.iomode == IOMODE_RW &&
3057 		    test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
3058 			list_add(&lseg->pls_lc_list, listp);
3059 	}
3060 }
3061 
3062 static void pnfs_list_write_lseg_done(struct inode *inode, struct list_head *listp)
3063 {
3064 	struct pnfs_layout_segment *lseg, *tmp;
3065 
3066 	/* Matched by references in pnfs_set_layoutcommit */
3067 	list_for_each_entry_safe(lseg, tmp, listp, pls_lc_list) {
3068 		list_del_init(&lseg->pls_lc_list);
3069 		pnfs_put_lseg(lseg);
3070 	}
3071 
3072 	pnfs_clear_layoutcommitting(inode);
3073 }
3074 
3075 void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg)
3076 {
3077 	pnfs_layout_io_set_failed(lseg->pls_layout, lseg->pls_range.iomode);
3078 }
3079 EXPORT_SYMBOL_GPL(pnfs_set_lo_fail);
3080 
3081 void
3082 pnfs_set_layoutcommit(struct inode *inode, struct pnfs_layout_segment *lseg,
3083 		loff_t end_pos)
3084 {
3085 	struct nfs_inode *nfsi = NFS_I(inode);
3086 	bool mark_as_dirty = false;
3087 
3088 	spin_lock(&inode->i_lock);
3089 	if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
3090 		nfsi->layout->plh_lwb = end_pos;
3091 		mark_as_dirty = true;
3092 		dprintk("%s: Set layoutcommit for inode %lu ",
3093 			__func__, inode->i_ino);
3094 	} else if (end_pos > nfsi->layout->plh_lwb)
3095 		nfsi->layout->plh_lwb = end_pos;
3096 	if (!test_and_set_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags)) {
3097 		/* references matched in nfs4_layoutcommit_release */
3098 		pnfs_get_lseg(lseg);
3099 	}
3100 	spin_unlock(&inode->i_lock);
3101 	dprintk("%s: lseg %p end_pos %llu\n",
3102 		__func__, lseg, nfsi->layout->plh_lwb);
3103 
3104 	/* if pnfs_layoutcommit_inode() runs between inode locks, the next one
3105 	 * will be a noop because NFS_INO_LAYOUTCOMMIT will not be set */
3106 	if (mark_as_dirty)
3107 		mark_inode_dirty_sync(inode);
3108 }
3109 EXPORT_SYMBOL_GPL(pnfs_set_layoutcommit);
3110 
3111 void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data)
3112 {
3113 	struct nfs_server *nfss = NFS_SERVER(data->args.inode);
3114 
3115 	if (nfss->pnfs_curr_ld->cleanup_layoutcommit)
3116 		nfss->pnfs_curr_ld->cleanup_layoutcommit(data);
3117 	pnfs_list_write_lseg_done(data->args.inode, &data->lseg_list);
3118 }
3119 
3120 /*
3121  * For the LAYOUT4_NFSV4_1_FILES layout type, NFS_DATA_SYNC WRITEs and
3122  * NFS_UNSTABLE WRITEs with a COMMIT to data servers must store enough
3123  * data to disk to allow the server to recover the data if it crashes.
3124  * LAYOUTCOMMIT is only needed when the NFL4_UFLG_COMMIT_THRU_MDS flag
3125  * is off, and a COMMIT is sent to a data server, or
3126  * if WRITEs to a data server return NFS_DATA_SYNC.
3127  */
3128 int
3129 pnfs_layoutcommit_inode(struct inode *inode, bool sync)
3130 {
3131 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
3132 	struct nfs4_layoutcommit_data *data;
3133 	struct nfs_inode *nfsi = NFS_I(inode);
3134 	loff_t end_pos;
3135 	int status;
3136 
3137 	if (!pnfs_layoutcommit_outstanding(inode))
3138 		return 0;
3139 
3140 	dprintk("--> %s inode %lu\n", __func__, inode->i_ino);
3141 
3142 	status = -EAGAIN;
3143 	if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
3144 		if (!sync)
3145 			goto out;
3146 		status = wait_on_bit_lock_action(&nfsi->flags,
3147 				NFS_INO_LAYOUTCOMMITTING,
3148 				nfs_wait_bit_killable,
3149 				TASK_KILLABLE);
3150 		if (status)
3151 			goto out;
3152 	}
3153 
3154 	status = -ENOMEM;
3155 	/* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
3156 	data = kzalloc(sizeof(*data), GFP_NOFS);
3157 	if (!data)
3158 		goto clear_layoutcommitting;
3159 
3160 	status = 0;
3161 	spin_lock(&inode->i_lock);
3162 	if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
3163 		goto out_unlock;
3164 
3165 	INIT_LIST_HEAD(&data->lseg_list);
3166 	pnfs_list_write_lseg(inode, &data->lseg_list);
3167 
3168 	end_pos = nfsi->layout->plh_lwb;
3169 
3170 	nfs4_stateid_copy(&data->args.stateid, &nfsi->layout->plh_stateid);
3171 	data->cred = get_cred(nfsi->layout->plh_lc_cred);
3172 	spin_unlock(&inode->i_lock);
3173 
3174 	data->args.inode = inode;
3175 	nfs_fattr_init(&data->fattr);
3176 	data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
3177 	data->res.fattr = &data->fattr;
3178 	if (end_pos != 0)
3179 		data->args.lastbytewritten = end_pos - 1;
3180 	else
3181 		data->args.lastbytewritten = U64_MAX;
3182 	data->res.server = NFS_SERVER(inode);
3183 
3184 	if (ld->prepare_layoutcommit) {
3185 		status = ld->prepare_layoutcommit(&data->args);
3186 		if (status) {
3187 			put_cred(data->cred);
3188 			spin_lock(&inode->i_lock);
3189 			set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags);
3190 			if (end_pos > nfsi->layout->plh_lwb)
3191 				nfsi->layout->plh_lwb = end_pos;
3192 			goto out_unlock;
3193 		}
3194 	}
3195 
3196 
3197 	status = nfs4_proc_layoutcommit(data, sync);
3198 out:
3199 	if (status)
3200 		mark_inode_dirty_sync(inode);
3201 	dprintk("<-- %s status %d\n", __func__, status);
3202 	return status;
3203 out_unlock:
3204 	spin_unlock(&inode->i_lock);
3205 	kfree(data);
3206 clear_layoutcommitting:
3207 	pnfs_clear_layoutcommitting(inode);
3208 	goto out;
3209 }
3210 EXPORT_SYMBOL_GPL(pnfs_layoutcommit_inode);
3211 
3212 int
3213 pnfs_generic_sync(struct inode *inode, bool datasync)
3214 {
3215 	return pnfs_layoutcommit_inode(inode, true);
3216 }
3217 EXPORT_SYMBOL_GPL(pnfs_generic_sync);
3218 
3219 struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
3220 {
3221 	struct nfs4_threshold *thp;
3222 
3223 	thp = kzalloc(sizeof(*thp), GFP_NOFS);
3224 	if (!thp) {
3225 		dprintk("%s mdsthreshold allocation failed\n", __func__);
3226 		return NULL;
3227 	}
3228 	return thp;
3229 }
3230 
3231 #if IS_ENABLED(CONFIG_NFS_V4_2)
3232 int
3233 pnfs_report_layoutstat(struct inode *inode, gfp_t gfp_flags)
3234 {
3235 	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
3236 	struct nfs_server *server = NFS_SERVER(inode);
3237 	struct nfs_inode *nfsi = NFS_I(inode);
3238 	struct nfs42_layoutstat_data *data;
3239 	struct pnfs_layout_hdr *hdr;
3240 	int status = 0;
3241 
3242 	if (!pnfs_enabled_sb(server) || !ld->prepare_layoutstats)
3243 		goto out;
3244 
3245 	if (!nfs_server_capable(inode, NFS_CAP_LAYOUTSTATS))
3246 		goto out;
3247 
3248 	if (test_and_set_bit(NFS_INO_LAYOUTSTATS, &nfsi->flags))
3249 		goto out;
3250 
3251 	spin_lock(&inode->i_lock);
3252 	if (!NFS_I(inode)->layout) {
3253 		spin_unlock(&inode->i_lock);
3254 		goto out_clear_layoutstats;
3255 	}
3256 	hdr = NFS_I(inode)->layout;
3257 	pnfs_get_layout_hdr(hdr);
3258 	spin_unlock(&inode->i_lock);
3259 
3260 	data = kzalloc(sizeof(*data), gfp_flags);
3261 	if (!data) {
3262 		status = -ENOMEM;
3263 		goto out_put;
3264 	}
3265 
3266 	data->args.fh = NFS_FH(inode);
3267 	data->args.inode = inode;
3268 	status = ld->prepare_layoutstats(&data->args);
3269 	if (status)
3270 		goto out_free;
3271 
3272 	status = nfs42_proc_layoutstats_generic(NFS_SERVER(inode), data);
3273 
3274 out:
3275 	dprintk("%s returns %d\n", __func__, status);
3276 	return status;
3277 
3278 out_free:
3279 	kfree(data);
3280 out_put:
3281 	pnfs_put_layout_hdr(hdr);
3282 out_clear_layoutstats:
3283 	smp_mb__before_atomic();
3284 	clear_bit(NFS_INO_LAYOUTSTATS, &nfsi->flags);
3285 	smp_mb__after_atomic();
3286 	goto out;
3287 }
3288 EXPORT_SYMBOL_GPL(pnfs_report_layoutstat);
3289 #endif
3290 
3291 unsigned int layoutstats_timer;
3292 module_param(layoutstats_timer, uint, 0644);
3293 EXPORT_SYMBOL_GPL(layoutstats_timer);
3294