1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * linux/fs/nfs/pagelist.c
4  *
5  * A set of helper functions for managing NFS read and write requests.
6  * The main purpose of these routines is to provide support for the
7  * coalescing of several requests into a single RPC call.
8  *
9  * Copyright 2000, 2001 (c) Trond Myklebust <trond.myklebust@fys.uio.no>
10  *
11  */
12 
13 #include <linux/slab.h>
14 #include <linux/file.h>
15 #include <linux/sched.h>
16 #include <linux/sunrpc/clnt.h>
17 #include <linux/nfs.h>
18 #include <linux/nfs3.h>
19 #include <linux/nfs4.h>
20 #include <linux/nfs_fs.h>
21 #include <linux/nfs_page.h>
22 #include <linux/nfs_mount.h>
23 #include <linux/export.h>
24 #include <linux/filelock.h>
25 
26 #include "internal.h"
27 #include "pnfs.h"
28 #include "nfstrace.h"
29 #include "fscache.h"
30 
31 #define NFSDBG_FACILITY		NFSDBG_PAGECACHE
32 
33 static struct kmem_cache *nfs_page_cachep;
34 static const struct rpc_call_ops nfs_pgio_common_ops;
35 
36 struct nfs_page_iter_page {
37 	const struct nfs_page *req;
38 	size_t count;
39 };
40 
nfs_page_iter_page_init(struct nfs_page_iter_page * i,const struct nfs_page * req)41 static void nfs_page_iter_page_init(struct nfs_page_iter_page *i,
42 				    const struct nfs_page *req)
43 {
44 	i->req = req;
45 	i->count = 0;
46 }
47 
nfs_page_iter_page_advance(struct nfs_page_iter_page * i,size_t sz)48 static void nfs_page_iter_page_advance(struct nfs_page_iter_page *i, size_t sz)
49 {
50 	const struct nfs_page *req = i->req;
51 	size_t tmp = i->count + sz;
52 
53 	i->count = (tmp < req->wb_bytes) ? tmp : req->wb_bytes;
54 }
55 
nfs_page_iter_page_get(struct nfs_page_iter_page * i)56 static struct page *nfs_page_iter_page_get(struct nfs_page_iter_page *i)
57 {
58 	const struct nfs_page *req = i->req;
59 	struct page *page;
60 
61 	if (i->count != req->wb_bytes) {
62 		size_t base = i->count + req->wb_pgbase;
63 		size_t len = PAGE_SIZE - offset_in_page(base);
64 
65 		page = nfs_page_to_page(req, base);
66 		nfs_page_iter_page_advance(i, len);
67 		return page;
68 	}
69 	return NULL;
70 }
71 
72 static struct nfs_pgio_mirror *
nfs_pgio_get_mirror(struct nfs_pageio_descriptor * desc,u32 idx)73 nfs_pgio_get_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
74 {
75 	if (desc->pg_ops->pg_get_mirror)
76 		return desc->pg_ops->pg_get_mirror(desc, idx);
77 	return &desc->pg_mirrors[0];
78 }
79 
80 struct nfs_pgio_mirror *
nfs_pgio_current_mirror(struct nfs_pageio_descriptor * desc)81 nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc)
82 {
83 	return nfs_pgio_get_mirror(desc, desc->pg_mirror_idx);
84 }
85 EXPORT_SYMBOL_GPL(nfs_pgio_current_mirror);
86 
87 static u32
nfs_pgio_set_current_mirror(struct nfs_pageio_descriptor * desc,u32 idx)88 nfs_pgio_set_current_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
89 {
90 	if (desc->pg_ops->pg_set_mirror)
91 		return desc->pg_ops->pg_set_mirror(desc, idx);
92 	return desc->pg_mirror_idx;
93 }
94 
nfs_pgheader_init(struct nfs_pageio_descriptor * desc,struct nfs_pgio_header * hdr,void (* release)(struct nfs_pgio_header * hdr))95 void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
96 		       struct nfs_pgio_header *hdr,
97 		       void (*release)(struct nfs_pgio_header *hdr))
98 {
99 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
100 
101 
102 	hdr->req = nfs_list_entry(mirror->pg_list.next);
103 	hdr->inode = desc->pg_inode;
104 	hdr->cred = nfs_req_openctx(hdr->req)->cred;
105 	hdr->io_start = req_offset(hdr->req);
106 	hdr->good_bytes = mirror->pg_count;
107 	hdr->io_completion = desc->pg_io_completion;
108 	hdr->dreq = desc->pg_dreq;
109 	nfs_netfs_set_pgio_header(hdr, desc);
110 	hdr->release = release;
111 	hdr->completion_ops = desc->pg_completion_ops;
112 	if (hdr->completion_ops->init_hdr)
113 		hdr->completion_ops->init_hdr(hdr);
114 
115 	hdr->pgio_mirror_idx = desc->pg_mirror_idx;
116 }
117 EXPORT_SYMBOL_GPL(nfs_pgheader_init);
118 
nfs_set_pgio_error(struct nfs_pgio_header * hdr,int error,loff_t pos)119 void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
120 {
121 	unsigned int new = pos - hdr->io_start;
122 
123 	trace_nfs_pgio_error(hdr, error, pos);
124 	if (hdr->good_bytes > new) {
125 		hdr->good_bytes = new;
126 		clear_bit(NFS_IOHDR_EOF, &hdr->flags);
127 		if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags))
128 			hdr->error = error;
129 	}
130 }
131 
nfs_page_alloc(void)132 static inline struct nfs_page *nfs_page_alloc(void)
133 {
134 	struct nfs_page *p =
135 		kmem_cache_zalloc(nfs_page_cachep, nfs_io_gfp_mask());
136 	if (p)
137 		INIT_LIST_HEAD(&p->wb_list);
138 	return p;
139 }
140 
141 static inline void
nfs_page_free(struct nfs_page * p)142 nfs_page_free(struct nfs_page *p)
143 {
144 	kmem_cache_free(nfs_page_cachep, p);
145 }
146 
147 /**
148  * nfs_iocounter_wait - wait for i/o to complete
149  * @l_ctx: nfs_lock_context with io_counter to use
150  *
151  * returns -ERESTARTSYS if interrupted by a fatal signal.
152  * Otherwise returns 0 once the io_count hits 0.
153  */
154 int
nfs_iocounter_wait(struct nfs_lock_context * l_ctx)155 nfs_iocounter_wait(struct nfs_lock_context *l_ctx)
156 {
157 	return wait_var_event_killable(&l_ctx->io_count,
158 				       !atomic_read(&l_ctx->io_count));
159 }
160 
161 /**
162  * nfs_async_iocounter_wait - wait on a rpc_waitqueue for I/O
163  * to complete
164  * @task: the rpc_task that should wait
165  * @l_ctx: nfs_lock_context with io_counter to check
166  *
167  * Returns true if there is outstanding I/O to wait on and the
168  * task has been put to sleep.
169  */
170 bool
nfs_async_iocounter_wait(struct rpc_task * task,struct nfs_lock_context * l_ctx)171 nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx)
172 {
173 	struct inode *inode = d_inode(l_ctx->open_context->dentry);
174 	bool ret = false;
175 
176 	if (atomic_read(&l_ctx->io_count) > 0) {
177 		rpc_sleep_on(&NFS_SERVER(inode)->uoc_rpcwaitq, task, NULL);
178 		ret = true;
179 	}
180 
181 	if (atomic_read(&l_ctx->io_count) == 0) {
182 		rpc_wake_up_queued_task(&NFS_SERVER(inode)->uoc_rpcwaitq, task);
183 		ret = false;
184 	}
185 
186 	return ret;
187 }
188 EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait);
189 
190 /*
191  * nfs_page_lock_head_request - page lock the head of the page group
192  * @req: any member of the page group
193  */
194 struct nfs_page *
nfs_page_group_lock_head(struct nfs_page * req)195 nfs_page_group_lock_head(struct nfs_page *req)
196 {
197 	struct nfs_page *head = req->wb_head;
198 
199 	while (!nfs_lock_request(head)) {
200 		int ret = nfs_wait_on_request(head);
201 		if (ret < 0)
202 			return ERR_PTR(ret);
203 	}
204 	if (head != req)
205 		kref_get(&head->wb_kref);
206 	return head;
207 }
208 
209 /*
210  * nfs_unroll_locks -  unlock all newly locked reqs and wait on @req
211  * @head: head request of page group, must be holding head lock
212  * @req: request that couldn't lock and needs to wait on the req bit lock
213  *
214  * This is a helper function for nfs_lock_and_join_requests
215  * returns 0 on success, < 0 on error.
216  */
217 static void
nfs_unroll_locks(struct nfs_page * head,struct nfs_page * req)218 nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req)
219 {
220 	struct nfs_page *tmp;
221 
222 	/* relinquish all the locks successfully grabbed this run */
223 	for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {
224 		if (!kref_read(&tmp->wb_kref))
225 			continue;
226 		nfs_unlock_and_release_request(tmp);
227 	}
228 }
229 
230 /*
231  * nfs_page_group_lock_subreq -  try to lock a subrequest
232  * @head: head request of page group
233  * @subreq: request to lock
234  *
235  * This is a helper function for nfs_lock_and_join_requests which
236  * must be called with the head request and page group both locked.
237  * On error, it returns with the page group unlocked.
238  */
239 static int
nfs_page_group_lock_subreq(struct nfs_page * head,struct nfs_page * subreq)240 nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq)
241 {
242 	int ret;
243 
244 	if (!kref_get_unless_zero(&subreq->wb_kref))
245 		return 0;
246 	while (!nfs_lock_request(subreq)) {
247 		nfs_page_group_unlock(head);
248 		ret = nfs_wait_on_request(subreq);
249 		if (!ret)
250 			ret = nfs_page_group_lock(head);
251 		if (ret < 0) {
252 			nfs_unroll_locks(head, subreq);
253 			nfs_release_request(subreq);
254 			return ret;
255 		}
256 	}
257 	return 0;
258 }
259 
260 /*
261  * nfs_page_group_lock_subrequests -  try to lock the subrequests
262  * @head: head request of page group
263  *
264  * This is a helper function for nfs_lock_and_join_requests which
265  * must be called with the head request locked.
266  */
nfs_page_group_lock_subrequests(struct nfs_page * head)267 int nfs_page_group_lock_subrequests(struct nfs_page *head)
268 {
269 	struct nfs_page *subreq;
270 	int ret;
271 
272 	ret = nfs_page_group_lock(head);
273 	if (ret < 0)
274 		return ret;
275 	/* lock each request in the page group */
276 	for (subreq = head->wb_this_page; subreq != head;
277 			subreq = subreq->wb_this_page) {
278 		ret = nfs_page_group_lock_subreq(head, subreq);
279 		if (ret < 0)
280 			return ret;
281 	}
282 	nfs_page_group_unlock(head);
283 	return 0;
284 }
285 
286 /*
287  * nfs_page_set_headlock - set the request PG_HEADLOCK
288  * @req: request that is to be locked
289  *
290  * this lock must be held when modifying req->wb_head
291  *
292  * return 0 on success, < 0 on error
293  */
294 int
nfs_page_set_headlock(struct nfs_page * req)295 nfs_page_set_headlock(struct nfs_page *req)
296 {
297 	if (!test_and_set_bit(PG_HEADLOCK, &req->wb_flags))
298 		return 0;
299 
300 	set_bit(PG_CONTENDED1, &req->wb_flags);
301 	smp_mb__after_atomic();
302 	return wait_on_bit_lock(&req->wb_flags, PG_HEADLOCK,
303 				TASK_UNINTERRUPTIBLE);
304 }
305 
306 /*
307  * nfs_page_clear_headlock - clear the request PG_HEADLOCK
308  * @req: request that is to be locked
309  */
310 void
nfs_page_clear_headlock(struct nfs_page * req)311 nfs_page_clear_headlock(struct nfs_page *req)
312 {
313 	clear_bit_unlock(PG_HEADLOCK, &req->wb_flags);
314 	smp_mb__after_atomic();
315 	if (!test_bit(PG_CONTENDED1, &req->wb_flags))
316 		return;
317 	wake_up_bit(&req->wb_flags, PG_HEADLOCK);
318 }
319 
320 /*
321  * nfs_page_group_lock - lock the head of the page group
322  * @req: request in group that is to be locked
323  *
324  * this lock must be held when traversing or modifying the page
325  * group list
326  *
327  * return 0 on success, < 0 on error
328  */
329 int
nfs_page_group_lock(struct nfs_page * req)330 nfs_page_group_lock(struct nfs_page *req)
331 {
332 	int ret;
333 
334 	ret = nfs_page_set_headlock(req);
335 	if (ret || req->wb_head == req)
336 		return ret;
337 	return nfs_page_set_headlock(req->wb_head);
338 }
339 
340 /*
341  * nfs_page_group_unlock - unlock the head of the page group
342  * @req: request in group that is to be unlocked
343  */
344 void
nfs_page_group_unlock(struct nfs_page * req)345 nfs_page_group_unlock(struct nfs_page *req)
346 {
347 	if (req != req->wb_head)
348 		nfs_page_clear_headlock(req->wb_head);
349 	nfs_page_clear_headlock(req);
350 }
351 
352 /*
353  * nfs_page_group_sync_on_bit_locked
354  *
355  * must be called with page group lock held
356  */
357 static bool
nfs_page_group_sync_on_bit_locked(struct nfs_page * req,unsigned int bit)358 nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit)
359 {
360 	struct nfs_page *head = req->wb_head;
361 	struct nfs_page *tmp;
362 
363 	WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_flags));
364 	WARN_ON_ONCE(test_and_set_bit(bit, &req->wb_flags));
365 
366 	tmp = req->wb_this_page;
367 	while (tmp != req) {
368 		if (!test_bit(bit, &tmp->wb_flags))
369 			return false;
370 		tmp = tmp->wb_this_page;
371 	}
372 
373 	/* true! reset all bits */
374 	tmp = req;
375 	do {
376 		clear_bit(bit, &tmp->wb_flags);
377 		tmp = tmp->wb_this_page;
378 	} while (tmp != req);
379 
380 	return true;
381 }
382 
383 /*
384  * nfs_page_group_sync_on_bit - set bit on current request, but only
385  *   return true if the bit is set for all requests in page group
386  * @req - request in page group
387  * @bit - PG_* bit that is used to sync page group
388  */
nfs_page_group_sync_on_bit(struct nfs_page * req,unsigned int bit)389 bool nfs_page_group_sync_on_bit(struct nfs_page *req, unsigned int bit)
390 {
391 	bool ret;
392 
393 	nfs_page_group_lock(req);
394 	ret = nfs_page_group_sync_on_bit_locked(req, bit);
395 	nfs_page_group_unlock(req);
396 
397 	return ret;
398 }
399 
400 /*
401  * nfs_page_group_init - Initialize the page group linkage for @req
402  * @req - a new nfs request
403  * @prev - the previous request in page group, or NULL if @req is the first
404  *         or only request in the group (the head).
405  */
406 static inline void
nfs_page_group_init(struct nfs_page * req,struct nfs_page * prev)407 nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev)
408 {
409 	struct inode *inode;
410 	WARN_ON_ONCE(prev == req);
411 
412 	if (!prev) {
413 		/* a head request */
414 		req->wb_head = req;
415 		req->wb_this_page = req;
416 	} else {
417 		/* a subrequest */
418 		WARN_ON_ONCE(prev->wb_this_page != prev->wb_head);
419 		WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags));
420 		req->wb_head = prev->wb_head;
421 		req->wb_this_page = prev->wb_this_page;
422 		prev->wb_this_page = req;
423 
424 		/* All subrequests take a ref on the head request until
425 		 * nfs_page_group_destroy is called */
426 		kref_get(&req->wb_head->wb_kref);
427 
428 		/* grab extra ref and bump the request count if head request
429 		 * has extra ref from the write/commit path to handle handoff
430 		 * between write and commit lists. */
431 		if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) {
432 			inode = nfs_page_to_inode(req);
433 			set_bit(PG_INODE_REF, &req->wb_flags);
434 			kref_get(&req->wb_kref);
435 			atomic_long_inc(&NFS_I(inode)->nrequests);
436 		}
437 	}
438 }
439 
440 /*
441  * nfs_page_group_destroy - sync the destruction of page groups
442  * @req - request that no longer needs the page group
443  *
444  * releases the page group reference from each member once all
445  * members have called this function.
446  */
447 static void
nfs_page_group_destroy(struct kref * kref)448 nfs_page_group_destroy(struct kref *kref)
449 {
450 	struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
451 	struct nfs_page *head = req->wb_head;
452 	struct nfs_page *tmp, *next;
453 
454 	if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN))
455 		goto out;
456 
457 	tmp = req;
458 	do {
459 		next = tmp->wb_this_page;
460 		/* unlink and free */
461 		tmp->wb_this_page = tmp;
462 		tmp->wb_head = tmp;
463 		nfs_free_request(tmp);
464 		tmp = next;
465 	} while (tmp != req);
466 out:
467 	/* subrequests must release the ref on the head request */
468 	if (head != req)
469 		nfs_release_request(head);
470 }
471 
nfs_page_create(struct nfs_lock_context * l_ctx,unsigned int pgbase,pgoff_t index,unsigned int offset,unsigned int count)472 static struct nfs_page *nfs_page_create(struct nfs_lock_context *l_ctx,
473 					unsigned int pgbase, pgoff_t index,
474 					unsigned int offset, unsigned int count)
475 {
476 	struct nfs_page		*req;
477 	struct nfs_open_context *ctx = l_ctx->open_context;
478 
479 	if (test_bit(NFS_CONTEXT_BAD, &ctx->flags))
480 		return ERR_PTR(-EBADF);
481 	/* try to allocate the request struct */
482 	req = nfs_page_alloc();
483 	if (req == NULL)
484 		return ERR_PTR(-ENOMEM);
485 
486 	req->wb_lock_context = l_ctx;
487 	refcount_inc(&l_ctx->count);
488 	atomic_inc(&l_ctx->io_count);
489 
490 	/* Initialize the request struct. Initially, we assume a
491 	 * long write-back delay. This will be adjusted in
492 	 * update_nfs_request below if the region is not locked. */
493 	req->wb_pgbase = pgbase;
494 	req->wb_index = index;
495 	req->wb_offset = offset;
496 	req->wb_bytes = count;
497 	kref_init(&req->wb_kref);
498 	req->wb_nio = 0;
499 	return req;
500 }
501 
nfs_page_assign_folio(struct nfs_page * req,struct folio * folio)502 static void nfs_page_assign_folio(struct nfs_page *req, struct folio *folio)
503 {
504 	if (folio != NULL) {
505 		req->wb_folio = folio;
506 		folio_get(folio);
507 		set_bit(PG_FOLIO, &req->wb_flags);
508 	}
509 }
510 
nfs_page_assign_page(struct nfs_page * req,struct page * page)511 static void nfs_page_assign_page(struct nfs_page *req, struct page *page)
512 {
513 	if (page != NULL) {
514 		req->wb_page = page;
515 		get_page(page);
516 	}
517 }
518 
519 /**
520  * nfs_page_create_from_page - Create an NFS read/write request.
521  * @ctx: open context to use
522  * @page: page to write
523  * @pgbase: starting offset within the page for the write
524  * @offset: file offset for the write
525  * @count: number of bytes to read/write
526  *
527  * The page must be locked by the caller. This makes sure we never
528  * create two different requests for the same page.
529  * User should ensure it is safe to sleep in this function.
530  */
nfs_page_create_from_page(struct nfs_open_context * ctx,struct page * page,unsigned int pgbase,loff_t offset,unsigned int count)531 struct nfs_page *nfs_page_create_from_page(struct nfs_open_context *ctx,
532 					   struct page *page,
533 					   unsigned int pgbase, loff_t offset,
534 					   unsigned int count)
535 {
536 	struct nfs_lock_context *l_ctx = nfs_get_lock_context(ctx);
537 	struct nfs_page *ret;
538 
539 	if (IS_ERR(l_ctx))
540 		return ERR_CAST(l_ctx);
541 	ret = nfs_page_create(l_ctx, pgbase, offset >> PAGE_SHIFT,
542 			      offset_in_page(offset), count);
543 	if (!IS_ERR(ret)) {
544 		nfs_page_assign_page(ret, page);
545 		nfs_page_group_init(ret, NULL);
546 	}
547 	nfs_put_lock_context(l_ctx);
548 	return ret;
549 }
550 
551 /**
552  * nfs_page_create_from_folio - Create an NFS read/write request.
553  * @ctx: open context to use
554  * @folio: folio to write
555  * @offset: starting offset within the folio for the write
556  * @count: number of bytes to read/write
557  *
558  * The page must be locked by the caller. This makes sure we never
559  * create two different requests for the same page.
560  * User should ensure it is safe to sleep in this function.
561  */
nfs_page_create_from_folio(struct nfs_open_context * ctx,struct folio * folio,unsigned int offset,unsigned int count)562 struct nfs_page *nfs_page_create_from_folio(struct nfs_open_context *ctx,
563 					    struct folio *folio,
564 					    unsigned int offset,
565 					    unsigned int count)
566 {
567 	struct nfs_lock_context *l_ctx = nfs_get_lock_context(ctx);
568 	struct nfs_page *ret;
569 
570 	if (IS_ERR(l_ctx))
571 		return ERR_CAST(l_ctx);
572 	ret = nfs_page_create(l_ctx, offset, folio_index(folio), offset, count);
573 	if (!IS_ERR(ret)) {
574 		nfs_page_assign_folio(ret, folio);
575 		nfs_page_group_init(ret, NULL);
576 	}
577 	nfs_put_lock_context(l_ctx);
578 	return ret;
579 }
580 
581 static struct nfs_page *
nfs_create_subreq(struct nfs_page * req,unsigned int pgbase,unsigned int offset,unsigned int count)582 nfs_create_subreq(struct nfs_page *req,
583 		  unsigned int pgbase,
584 		  unsigned int offset,
585 		  unsigned int count)
586 {
587 	struct nfs_page *last;
588 	struct nfs_page *ret;
589 	struct folio *folio = nfs_page_to_folio(req);
590 	struct page *page = nfs_page_to_page(req, pgbase);
591 
592 	ret = nfs_page_create(req->wb_lock_context, pgbase, req->wb_index,
593 			      offset, count);
594 	if (!IS_ERR(ret)) {
595 		if (folio)
596 			nfs_page_assign_folio(ret, folio);
597 		else
598 			nfs_page_assign_page(ret, page);
599 		/* find the last request */
600 		for (last = req->wb_head;
601 		     last->wb_this_page != req->wb_head;
602 		     last = last->wb_this_page)
603 			;
604 
605 		nfs_lock_request(ret);
606 		nfs_page_group_init(ret, last);
607 		ret->wb_nio = req->wb_nio;
608 	}
609 	return ret;
610 }
611 
612 /**
613  * nfs_unlock_request - Unlock request and wake up sleepers.
614  * @req: pointer to request
615  */
nfs_unlock_request(struct nfs_page * req)616 void nfs_unlock_request(struct nfs_page *req)
617 {
618 	clear_bit_unlock(PG_BUSY, &req->wb_flags);
619 	smp_mb__after_atomic();
620 	if (!test_bit(PG_CONTENDED2, &req->wb_flags))
621 		return;
622 	wake_up_bit(&req->wb_flags, PG_BUSY);
623 }
624 
625 /**
626  * nfs_unlock_and_release_request - Unlock request and release the nfs_page
627  * @req: pointer to request
628  */
nfs_unlock_and_release_request(struct nfs_page * req)629 void nfs_unlock_and_release_request(struct nfs_page *req)
630 {
631 	nfs_unlock_request(req);
632 	nfs_release_request(req);
633 }
634 
635 /*
636  * nfs_clear_request - Free up all resources allocated to the request
637  * @req:
638  *
639  * Release page and open context resources associated with a read/write
640  * request after it has completed.
641  */
nfs_clear_request(struct nfs_page * req)642 static void nfs_clear_request(struct nfs_page *req)
643 {
644 	struct folio *folio = nfs_page_to_folio(req);
645 	struct page *page = req->wb_page;
646 	struct nfs_lock_context *l_ctx = req->wb_lock_context;
647 	struct nfs_open_context *ctx;
648 
649 	if (folio != NULL) {
650 		folio_put(folio);
651 		req->wb_folio = NULL;
652 		clear_bit(PG_FOLIO, &req->wb_flags);
653 	} else if (page != NULL) {
654 		put_page(page);
655 		req->wb_page = NULL;
656 	}
657 	if (l_ctx != NULL) {
658 		if (atomic_dec_and_test(&l_ctx->io_count)) {
659 			wake_up_var(&l_ctx->io_count);
660 			ctx = l_ctx->open_context;
661 			if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags))
662 				rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq);
663 		}
664 		nfs_put_lock_context(l_ctx);
665 		req->wb_lock_context = NULL;
666 	}
667 }
668 
669 /**
670  * nfs_free_request - Release the count on an NFS read/write request
671  * @req: request to release
672  *
673  * Note: Should never be called with the spinlock held!
674  */
nfs_free_request(struct nfs_page * req)675 void nfs_free_request(struct nfs_page *req)
676 {
677 	WARN_ON_ONCE(req->wb_this_page != req);
678 
679 	/* extra debug: make sure no sync bits are still set */
680 	WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
681 	WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
682 	WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
683 	WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
684 	WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
685 
686 	/* Release struct file and open context */
687 	nfs_clear_request(req);
688 	nfs_page_free(req);
689 }
690 
nfs_release_request(struct nfs_page * req)691 void nfs_release_request(struct nfs_page *req)
692 {
693 	kref_put(&req->wb_kref, nfs_page_group_destroy);
694 }
695 EXPORT_SYMBOL_GPL(nfs_release_request);
696 
697 /**
698  * nfs_wait_on_request - Wait for a request to complete.
699  * @req: request to wait upon.
700  *
701  * Interruptible by fatal signals only.
702  * The user is responsible for holding a count on the request.
703  */
704 int
nfs_wait_on_request(struct nfs_page * req)705 nfs_wait_on_request(struct nfs_page *req)
706 {
707 	if (!test_bit(PG_BUSY, &req->wb_flags))
708 		return 0;
709 	set_bit(PG_CONTENDED2, &req->wb_flags);
710 	smp_mb__after_atomic();
711 	return wait_on_bit_io(&req->wb_flags, PG_BUSY,
712 			      TASK_UNINTERRUPTIBLE);
713 }
714 EXPORT_SYMBOL_GPL(nfs_wait_on_request);
715 
716 /*
717  * nfs_generic_pg_test - determine if requests can be coalesced
718  * @desc: pointer to descriptor
719  * @prev: previous request in desc, or NULL
720  * @req: this request
721  *
722  * Returns zero if @req cannot be coalesced into @desc, otherwise it returns
723  * the size of the request.
724  */
nfs_generic_pg_test(struct nfs_pageio_descriptor * desc,struct nfs_page * prev,struct nfs_page * req)725 size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
726 			   struct nfs_page *prev, struct nfs_page *req)
727 {
728 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
729 
730 
731 	if (mirror->pg_count > mirror->pg_bsize) {
732 		/* should never happen */
733 		WARN_ON_ONCE(1);
734 		return 0;
735 	}
736 
737 	/*
738 	 * Limit the request size so that we can still allocate a page array
739 	 * for it without upsetting the slab allocator.
740 	 */
741 	if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
742 			sizeof(struct page *) > PAGE_SIZE)
743 		return 0;
744 
745 	return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes);
746 }
747 EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
748 
nfs_pgio_header_alloc(const struct nfs_rw_ops * ops)749 struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
750 {
751 	struct nfs_pgio_header *hdr = ops->rw_alloc_header();
752 
753 	if (hdr) {
754 		INIT_LIST_HEAD(&hdr->pages);
755 		hdr->rw_ops = ops;
756 	}
757 	return hdr;
758 }
759 EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
760 
761 /**
762  * nfs_pgio_data_destroy - make @hdr suitable for reuse
763  *
764  * Frees memory and releases refs from nfs_generic_pgio, so that it may
765  * be called again.
766  *
767  * @hdr: A header that has had nfs_generic_pgio called
768  */
nfs_pgio_data_destroy(struct nfs_pgio_header * hdr)769 static void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
770 {
771 	if (hdr->args.context)
772 		put_nfs_open_context(hdr->args.context);
773 	if (hdr->page_array.pagevec != hdr->page_array.page_array)
774 		kfree(hdr->page_array.pagevec);
775 }
776 
777 /*
778  * nfs_pgio_header_free - Free a read or write header
779  * @hdr: The header to free
780  */
nfs_pgio_header_free(struct nfs_pgio_header * hdr)781 void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
782 {
783 	nfs_pgio_data_destroy(hdr);
784 	hdr->rw_ops->rw_free_header(hdr);
785 }
786 EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
787 
788 /**
789  * nfs_pgio_rpcsetup - Set up arguments for a pageio call
790  * @hdr: The pageio hdr
791  * @pgbase: base
792  * @count: Number of bytes to read
793  * @how: How to commit data (writes only)
794  * @cinfo: Commit information for the call (writes only)
795  */
nfs_pgio_rpcsetup(struct nfs_pgio_header * hdr,unsigned int pgbase,unsigned int count,int how,struct nfs_commit_info * cinfo)796 static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr, unsigned int pgbase,
797 			      unsigned int count, int how,
798 			      struct nfs_commit_info *cinfo)
799 {
800 	struct nfs_page *req = hdr->req;
801 
802 	/* Set up the RPC argument and reply structs
803 	 * NB: take care not to mess about with hdr->commit et al. */
804 
805 	hdr->args.fh     = NFS_FH(hdr->inode);
806 	hdr->args.offset = req_offset(req);
807 	/* pnfs_set_layoutcommit needs this */
808 	hdr->mds_offset = hdr->args.offset;
809 	hdr->args.pgbase = pgbase;
810 	hdr->args.pages  = hdr->page_array.pagevec;
811 	hdr->args.count  = count;
812 	hdr->args.context = get_nfs_open_context(nfs_req_openctx(req));
813 	hdr->args.lock_context = req->wb_lock_context;
814 	hdr->args.stable  = NFS_UNSTABLE;
815 	switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
816 	case 0:
817 		break;
818 	case FLUSH_COND_STABLE:
819 		if (nfs_reqs_to_commit(cinfo))
820 			break;
821 		fallthrough;
822 	default:
823 		hdr->args.stable = NFS_FILE_SYNC;
824 	}
825 
826 	hdr->res.fattr   = &hdr->fattr;
827 	hdr->res.count   = 0;
828 	hdr->res.eof     = 0;
829 	hdr->res.verf    = &hdr->verf;
830 	nfs_fattr_init(&hdr->fattr);
831 }
832 
833 /**
834  * nfs_pgio_prepare - Prepare pageio hdr to go over the wire
835  * @task: The current task
836  * @calldata: pageio header to prepare
837  */
nfs_pgio_prepare(struct rpc_task * task,void * calldata)838 static void nfs_pgio_prepare(struct rpc_task *task, void *calldata)
839 {
840 	struct nfs_pgio_header *hdr = calldata;
841 	int err;
842 	err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr);
843 	if (err)
844 		rpc_exit(task, err);
845 }
846 
nfs_initiate_pgio(struct rpc_clnt * clnt,struct nfs_pgio_header * hdr,const struct cred * cred,const struct nfs_rpc_ops * rpc_ops,const struct rpc_call_ops * call_ops,int how,int flags)847 int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr,
848 		      const struct cred *cred, const struct nfs_rpc_ops *rpc_ops,
849 		      const struct rpc_call_ops *call_ops, int how, int flags)
850 {
851 	struct rpc_task *task;
852 	struct rpc_message msg = {
853 		.rpc_argp = &hdr->args,
854 		.rpc_resp = &hdr->res,
855 		.rpc_cred = cred,
856 	};
857 	struct rpc_task_setup task_setup_data = {
858 		.rpc_client = clnt,
859 		.task = &hdr->task,
860 		.rpc_message = &msg,
861 		.callback_ops = call_ops,
862 		.callback_data = hdr,
863 		.workqueue = nfsiod_workqueue,
864 		.flags = RPC_TASK_ASYNC | flags,
865 	};
866 
867 	if (nfs_server_capable(hdr->inode, NFS_CAP_MOVEABLE))
868 		task_setup_data.flags |= RPC_TASK_MOVEABLE;
869 
870 	hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how);
871 
872 	dprintk("NFS: initiated pgio call "
873 		"(req %s/%llu, %u bytes @ offset %llu)\n",
874 		hdr->inode->i_sb->s_id,
875 		(unsigned long long)NFS_FILEID(hdr->inode),
876 		hdr->args.count,
877 		(unsigned long long)hdr->args.offset);
878 
879 	task = rpc_run_task(&task_setup_data);
880 	if (IS_ERR(task))
881 		return PTR_ERR(task);
882 	rpc_put_task(task);
883 	return 0;
884 }
885 EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
886 
887 /**
888  * nfs_pgio_error - Clean up from a pageio error
889  * @hdr: pageio header
890  */
nfs_pgio_error(struct nfs_pgio_header * hdr)891 static void nfs_pgio_error(struct nfs_pgio_header *hdr)
892 {
893 	set_bit(NFS_IOHDR_REDO, &hdr->flags);
894 	hdr->completion_ops->completion(hdr);
895 }
896 
897 /**
898  * nfs_pgio_release - Release pageio data
899  * @calldata: The pageio header to release
900  */
nfs_pgio_release(void * calldata)901 static void nfs_pgio_release(void *calldata)
902 {
903 	struct nfs_pgio_header *hdr = calldata;
904 	hdr->completion_ops->completion(hdr);
905 }
906 
nfs_pageio_mirror_init(struct nfs_pgio_mirror * mirror,unsigned int bsize)907 static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror,
908 				   unsigned int bsize)
909 {
910 	INIT_LIST_HEAD(&mirror->pg_list);
911 	mirror->pg_bytes_written = 0;
912 	mirror->pg_count = 0;
913 	mirror->pg_bsize = bsize;
914 	mirror->pg_base = 0;
915 	mirror->pg_recoalesce = 0;
916 }
917 
918 /**
919  * nfs_pageio_init - initialise a page io descriptor
920  * @desc: pointer to descriptor
921  * @inode: pointer to inode
922  * @pg_ops: pointer to pageio operations
923  * @compl_ops: pointer to pageio completion operations
924  * @rw_ops: pointer to nfs read/write operations
925  * @bsize: io block size
926  * @io_flags: extra parameters for the io function
927  */
nfs_pageio_init(struct nfs_pageio_descriptor * desc,struct inode * inode,const struct nfs_pageio_ops * pg_ops,const struct nfs_pgio_completion_ops * compl_ops,const struct nfs_rw_ops * rw_ops,size_t bsize,int io_flags)928 void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
929 		     struct inode *inode,
930 		     const struct nfs_pageio_ops *pg_ops,
931 		     const struct nfs_pgio_completion_ops *compl_ops,
932 		     const struct nfs_rw_ops *rw_ops,
933 		     size_t bsize,
934 		     int io_flags)
935 {
936 	desc->pg_moreio = 0;
937 	desc->pg_inode = inode;
938 	desc->pg_ops = pg_ops;
939 	desc->pg_completion_ops = compl_ops;
940 	desc->pg_rw_ops = rw_ops;
941 	desc->pg_ioflags = io_flags;
942 	desc->pg_error = 0;
943 	desc->pg_lseg = NULL;
944 	desc->pg_io_completion = NULL;
945 	desc->pg_dreq = NULL;
946 	nfs_netfs_reset_pageio_descriptor(desc);
947 	desc->pg_bsize = bsize;
948 
949 	desc->pg_mirror_count = 1;
950 	desc->pg_mirror_idx = 0;
951 
952 	desc->pg_mirrors_dynamic = NULL;
953 	desc->pg_mirrors = desc->pg_mirrors_static;
954 	nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);
955 	desc->pg_maxretrans = 0;
956 }
957 
958 /**
959  * nfs_pgio_result - Basic pageio error handling
960  * @task: The task that ran
961  * @calldata: Pageio header to check
962  */
nfs_pgio_result(struct rpc_task * task,void * calldata)963 static void nfs_pgio_result(struct rpc_task *task, void *calldata)
964 {
965 	struct nfs_pgio_header *hdr = calldata;
966 	struct inode *inode = hdr->inode;
967 
968 	if (hdr->rw_ops->rw_done(task, hdr, inode) != 0)
969 		return;
970 	if (task->tk_status < 0)
971 		nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset);
972 	else
973 		hdr->rw_ops->rw_result(task, hdr);
974 }
975 
976 /*
977  * Create an RPC task for the given read or write request and kick it.
978  * The page must have been locked by the caller.
979  *
980  * It may happen that the page we're passed is not marked dirty.
981  * This is the case if nfs_updatepage detects a conflicting request
982  * that has been written but not committed.
983  */
nfs_generic_pgio(struct nfs_pageio_descriptor * desc,struct nfs_pgio_header * hdr)984 int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
985 		     struct nfs_pgio_header *hdr)
986 {
987 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
988 
989 	struct nfs_page		*req;
990 	struct page		**pages,
991 				*last_page;
992 	struct list_head *head = &mirror->pg_list;
993 	struct nfs_commit_info cinfo;
994 	struct nfs_page_array *pg_array = &hdr->page_array;
995 	unsigned int pagecount, pageused;
996 	unsigned int pg_base = offset_in_page(mirror->pg_base);
997 	gfp_t gfp_flags = nfs_io_gfp_mask();
998 
999 	pagecount = nfs_page_array_len(pg_base, mirror->pg_count);
1000 	pg_array->npages = pagecount;
1001 
1002 	if (pagecount <= ARRAY_SIZE(pg_array->page_array))
1003 		pg_array->pagevec = pg_array->page_array;
1004 	else {
1005 		pg_array->pagevec = kcalloc(pagecount, sizeof(struct page *), gfp_flags);
1006 		if (!pg_array->pagevec) {
1007 			pg_array->npages = 0;
1008 			nfs_pgio_error(hdr);
1009 			desc->pg_error = -ENOMEM;
1010 			return desc->pg_error;
1011 		}
1012 	}
1013 
1014 	nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
1015 	pages = hdr->page_array.pagevec;
1016 	last_page = NULL;
1017 	pageused = 0;
1018 	while (!list_empty(head)) {
1019 		struct nfs_page_iter_page i;
1020 		struct page *page;
1021 
1022 		req = nfs_list_entry(head->next);
1023 		nfs_list_move_request(req, &hdr->pages);
1024 
1025 		if (req->wb_pgbase == 0)
1026 			last_page = NULL;
1027 
1028 		nfs_page_iter_page_init(&i, req);
1029 		while ((page = nfs_page_iter_page_get(&i)) != NULL) {
1030 			if (last_page != page) {
1031 				pageused++;
1032 				if (pageused > pagecount)
1033 					goto full;
1034 				*pages++ = last_page = page;
1035 			}
1036 		}
1037 	}
1038 full:
1039 	if (WARN_ON_ONCE(pageused != pagecount)) {
1040 		nfs_pgio_error(hdr);
1041 		desc->pg_error = -EINVAL;
1042 		return desc->pg_error;
1043 	}
1044 
1045 	if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1046 	    (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
1047 		desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1048 
1049 	/* Set up the argument struct */
1050 	nfs_pgio_rpcsetup(hdr, pg_base, mirror->pg_count, desc->pg_ioflags,
1051 			  &cinfo);
1052 	desc->pg_rpc_callops = &nfs_pgio_common_ops;
1053 	return 0;
1054 }
1055 EXPORT_SYMBOL_GPL(nfs_generic_pgio);
1056 
nfs_generic_pg_pgios(struct nfs_pageio_descriptor * desc)1057 static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
1058 {
1059 	struct nfs_pgio_header *hdr;
1060 	int ret;
1061 	unsigned short task_flags = 0;
1062 
1063 	hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
1064 	if (!hdr) {
1065 		desc->pg_error = -ENOMEM;
1066 		return desc->pg_error;
1067 	}
1068 	nfs_pgheader_init(desc, hdr, nfs_pgio_header_free);
1069 	ret = nfs_generic_pgio(desc, hdr);
1070 	if (ret == 0) {
1071 		if (NFS_SERVER(hdr->inode)->nfs_client->cl_minorversion)
1072 			task_flags = RPC_TASK_MOVEABLE;
1073 		ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
1074 					hdr,
1075 					hdr->cred,
1076 					NFS_PROTO(hdr->inode),
1077 					desc->pg_rpc_callops,
1078 					desc->pg_ioflags,
1079 					RPC_TASK_CRED_NOREF | task_flags);
1080 	}
1081 	return ret;
1082 }
1083 
1084 static struct nfs_pgio_mirror *
nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor * desc,unsigned int mirror_count)1085 nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,
1086 		unsigned int mirror_count)
1087 {
1088 	struct nfs_pgio_mirror *ret;
1089 	unsigned int i;
1090 
1091 	kfree(desc->pg_mirrors_dynamic);
1092 	desc->pg_mirrors_dynamic = NULL;
1093 	if (mirror_count == 1)
1094 		return desc->pg_mirrors_static;
1095 	ret = kmalloc_array(mirror_count, sizeof(*ret), nfs_io_gfp_mask());
1096 	if (ret != NULL) {
1097 		for (i = 0; i < mirror_count; i++)
1098 			nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);
1099 		desc->pg_mirrors_dynamic = ret;
1100 	}
1101 	return ret;
1102 }
1103 
1104 /*
1105  * nfs_pageio_setup_mirroring - determine if mirroring is to be used
1106  *				by calling the pg_get_mirror_count op
1107  */
nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor * pgio,struct nfs_page * req)1108 static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,
1109 				       struct nfs_page *req)
1110 {
1111 	unsigned int mirror_count = 1;
1112 
1113 	if (pgio->pg_ops->pg_get_mirror_count)
1114 		mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);
1115 	if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0)
1116 		return;
1117 
1118 	if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) {
1119 		pgio->pg_error = -EINVAL;
1120 		return;
1121 	}
1122 
1123 	pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count);
1124 	if (pgio->pg_mirrors == NULL) {
1125 		pgio->pg_error = -ENOMEM;
1126 		pgio->pg_mirrors = pgio->pg_mirrors_static;
1127 		mirror_count = 1;
1128 	}
1129 	pgio->pg_mirror_count = mirror_count;
1130 }
1131 
nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor * pgio)1132 static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio)
1133 {
1134 	pgio->pg_mirror_count = 1;
1135 	pgio->pg_mirror_idx = 0;
1136 	pgio->pg_mirrors = pgio->pg_mirrors_static;
1137 	kfree(pgio->pg_mirrors_dynamic);
1138 	pgio->pg_mirrors_dynamic = NULL;
1139 }
1140 
nfs_match_lock_context(const struct nfs_lock_context * l1,const struct nfs_lock_context * l2)1141 static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
1142 		const struct nfs_lock_context *l2)
1143 {
1144 	return l1->lockowner == l2->lockowner;
1145 }
1146 
nfs_page_is_contiguous(const struct nfs_page * prev,const struct nfs_page * req)1147 static bool nfs_page_is_contiguous(const struct nfs_page *prev,
1148 				   const struct nfs_page *req)
1149 {
1150 	size_t prev_end = prev->wb_pgbase + prev->wb_bytes;
1151 
1152 	if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
1153 		return false;
1154 	if (req->wb_pgbase == 0)
1155 		return prev_end == nfs_page_max_length(prev);
1156 	if (req->wb_pgbase == prev_end) {
1157 		struct folio *folio = nfs_page_to_folio(req);
1158 		if (folio)
1159 			return folio == nfs_page_to_folio(prev);
1160 		return req->wb_page == prev->wb_page;
1161 	}
1162 	return false;
1163 }
1164 
1165 /**
1166  * nfs_coalesce_size - test two requests for compatibility
1167  * @prev: pointer to nfs_page
1168  * @req: pointer to nfs_page
1169  * @pgio: pointer to nfs_pagio_descriptor
1170  *
1171  * The nfs_page structures 'prev' and 'req' are compared to ensure that the
1172  * page data area they describe is contiguous, and that their RPC
1173  * credentials, NFSv4 open state, and lockowners are the same.
1174  *
1175  * Returns size of the request that can be coalesced
1176  */
nfs_coalesce_size(struct nfs_page * prev,struct nfs_page * req,struct nfs_pageio_descriptor * pgio)1177 static unsigned int nfs_coalesce_size(struct nfs_page *prev,
1178 				      struct nfs_page *req,
1179 				      struct nfs_pageio_descriptor *pgio)
1180 {
1181 	struct file_lock_context *flctx;
1182 
1183 	if (prev) {
1184 		if (!nfs_match_open_context(nfs_req_openctx(req), nfs_req_openctx(prev)))
1185 			return 0;
1186 		flctx = locks_inode_context(d_inode(nfs_req_openctx(req)->dentry));
1187 		if (flctx != NULL &&
1188 		    !(list_empty_careful(&flctx->flc_posix) &&
1189 		      list_empty_careful(&flctx->flc_flock)) &&
1190 		    !nfs_match_lock_context(req->wb_lock_context,
1191 					    prev->wb_lock_context))
1192 			return 0;
1193 		if (!nfs_page_is_contiguous(prev, req))
1194 			return 0;
1195 	}
1196 	return pgio->pg_ops->pg_test(pgio, prev, req);
1197 }
1198 
1199 /**
1200  * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
1201  * @desc: destination io descriptor
1202  * @req: request
1203  *
1204  * If the request 'req' was successfully coalesced into the existing list
1205  * of pages 'desc', it returns the size of req.
1206  */
1207 static unsigned int
nfs_pageio_do_add_request(struct nfs_pageio_descriptor * desc,struct nfs_page * req)1208 nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
1209 		struct nfs_page *req)
1210 {
1211 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1212 	struct nfs_page *prev = NULL;
1213 	unsigned int size;
1214 
1215 	if (list_empty(&mirror->pg_list)) {
1216 		if (desc->pg_ops->pg_init)
1217 			desc->pg_ops->pg_init(desc, req);
1218 		if (desc->pg_error < 0)
1219 			return 0;
1220 		mirror->pg_base = req->wb_pgbase;
1221 		mirror->pg_count = 0;
1222 		mirror->pg_recoalesce = 0;
1223 	} else
1224 		prev = nfs_list_entry(mirror->pg_list.prev);
1225 
1226 	if (desc->pg_maxretrans && req->wb_nio > desc->pg_maxretrans) {
1227 		if (NFS_SERVER(desc->pg_inode)->flags & NFS_MOUNT_SOFTERR)
1228 			desc->pg_error = -ETIMEDOUT;
1229 		else
1230 			desc->pg_error = -EIO;
1231 		return 0;
1232 	}
1233 
1234 	size = nfs_coalesce_size(prev, req, desc);
1235 	if (size < req->wb_bytes)
1236 		return size;
1237 	nfs_list_move_request(req, &mirror->pg_list);
1238 	mirror->pg_count += req->wb_bytes;
1239 	return req->wb_bytes;
1240 }
1241 
1242 /*
1243  * Helper for nfs_pageio_add_request and nfs_pageio_complete
1244  */
nfs_pageio_doio(struct nfs_pageio_descriptor * desc)1245 static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
1246 {
1247 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1248 
1249 	if (!list_empty(&mirror->pg_list)) {
1250 		int error = desc->pg_ops->pg_doio(desc);
1251 		if (error < 0)
1252 			desc->pg_error = error;
1253 		if (list_empty(&mirror->pg_list))
1254 			mirror->pg_bytes_written += mirror->pg_count;
1255 	}
1256 }
1257 
1258 static void
nfs_pageio_cleanup_request(struct nfs_pageio_descriptor * desc,struct nfs_page * req)1259 nfs_pageio_cleanup_request(struct nfs_pageio_descriptor *desc,
1260 		struct nfs_page *req)
1261 {
1262 	LIST_HEAD(head);
1263 
1264 	nfs_list_move_request(req, &head);
1265 	desc->pg_completion_ops->error_cleanup(&head, desc->pg_error);
1266 }
1267 
1268 /**
1269  * __nfs_pageio_add_request - Attempt to coalesce a request into a page list.
1270  * @desc: destination io descriptor
1271  * @req: request
1272  *
1273  * This may split a request into subrequests which are all part of the
1274  * same page group. If so, it will submit @req as the last one, to ensure
1275  * the pointer to @req is still valid in case of failure.
1276  *
1277  * Returns true if the request 'req' was successfully coalesced into the
1278  * existing list of pages 'desc'.
1279  */
__nfs_pageio_add_request(struct nfs_pageio_descriptor * desc,struct nfs_page * req)1280 static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1281 			   struct nfs_page *req)
1282 {
1283 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1284 	struct nfs_page *subreq;
1285 	unsigned int size, subreq_size;
1286 
1287 	nfs_page_group_lock(req);
1288 
1289 	subreq = req;
1290 	subreq_size = subreq->wb_bytes;
1291 	for(;;) {
1292 		size = nfs_pageio_do_add_request(desc, subreq);
1293 		if (size == subreq_size) {
1294 			/* We successfully submitted a request */
1295 			if (subreq == req)
1296 				break;
1297 			req->wb_pgbase += size;
1298 			req->wb_bytes -= size;
1299 			req->wb_offset += size;
1300 			subreq_size = req->wb_bytes;
1301 			subreq = req;
1302 			continue;
1303 		}
1304 		if (WARN_ON_ONCE(subreq != req)) {
1305 			nfs_page_group_unlock(req);
1306 			nfs_pageio_cleanup_request(desc, subreq);
1307 			subreq = req;
1308 			subreq_size = req->wb_bytes;
1309 			nfs_page_group_lock(req);
1310 		}
1311 		if (!size) {
1312 			/* Can't coalesce any more, so do I/O */
1313 			nfs_page_group_unlock(req);
1314 			desc->pg_moreio = 1;
1315 			nfs_pageio_doio(desc);
1316 			if (desc->pg_error < 0 || mirror->pg_recoalesce)
1317 				return 0;
1318 			/* retry add_request for this subreq */
1319 			nfs_page_group_lock(req);
1320 			continue;
1321 		}
1322 		subreq = nfs_create_subreq(req, req->wb_pgbase,
1323 				req->wb_offset, size);
1324 		if (IS_ERR(subreq))
1325 			goto err_ptr;
1326 		subreq_size = size;
1327 	}
1328 
1329 	nfs_page_group_unlock(req);
1330 	return 1;
1331 err_ptr:
1332 	desc->pg_error = PTR_ERR(subreq);
1333 	nfs_page_group_unlock(req);
1334 	return 0;
1335 }
1336 
nfs_do_recoalesce(struct nfs_pageio_descriptor * desc)1337 static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
1338 {
1339 	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1340 	LIST_HEAD(head);
1341 
1342 	do {
1343 		list_splice_init(&mirror->pg_list, &head);
1344 		mirror->pg_recoalesce = 0;
1345 
1346 		while (!list_empty(&head)) {
1347 			struct nfs_page *req;
1348 
1349 			req = list_first_entry(&head, struct nfs_page, wb_list);
1350 			if (__nfs_pageio_add_request(desc, req))
1351 				continue;
1352 			if (desc->pg_error < 0) {
1353 				list_splice_tail(&head, &mirror->pg_list);
1354 				mirror->pg_recoalesce = 1;
1355 				return 0;
1356 			}
1357 			break;
1358 		}
1359 	} while (mirror->pg_recoalesce);
1360 	return 1;
1361 }
1362 
nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor * desc,struct nfs_page * req)1363 static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc,
1364 		struct nfs_page *req)
1365 {
1366 	int ret;
1367 
1368 	do {
1369 		ret = __nfs_pageio_add_request(desc, req);
1370 		if (ret)
1371 			break;
1372 		if (desc->pg_error < 0)
1373 			break;
1374 		ret = nfs_do_recoalesce(desc);
1375 	} while (ret);
1376 
1377 	return ret;
1378 }
1379 
nfs_pageio_error_cleanup(struct nfs_pageio_descriptor * desc)1380 static void nfs_pageio_error_cleanup(struct nfs_pageio_descriptor *desc)
1381 {
1382 	u32 midx;
1383 	struct nfs_pgio_mirror *mirror;
1384 
1385 	if (!desc->pg_error)
1386 		return;
1387 
1388 	for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1389 		mirror = nfs_pgio_get_mirror(desc, midx);
1390 		desc->pg_completion_ops->error_cleanup(&mirror->pg_list,
1391 				desc->pg_error);
1392 	}
1393 }
1394 
nfs_pageio_add_request(struct nfs_pageio_descriptor * desc,struct nfs_page * req)1395 int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1396 			   struct nfs_page *req)
1397 {
1398 	u32 midx;
1399 	unsigned int pgbase, offset, bytes;
1400 	struct nfs_page *dupreq;
1401 
1402 	pgbase = req->wb_pgbase;
1403 	offset = req->wb_offset;
1404 	bytes = req->wb_bytes;
1405 
1406 	nfs_pageio_setup_mirroring(desc, req);
1407 	if (desc->pg_error < 0)
1408 		goto out_failed;
1409 
1410 	/* Create the mirror instances first, and fire them off */
1411 	for (midx = 1; midx < desc->pg_mirror_count; midx++) {
1412 		nfs_page_group_lock(req);
1413 
1414 		dupreq = nfs_create_subreq(req,
1415 				pgbase, offset, bytes);
1416 
1417 		nfs_page_group_unlock(req);
1418 		if (IS_ERR(dupreq)) {
1419 			desc->pg_error = PTR_ERR(dupreq);
1420 			goto out_failed;
1421 		}
1422 
1423 		nfs_pgio_set_current_mirror(desc, midx);
1424 		if (!nfs_pageio_add_request_mirror(desc, dupreq))
1425 			goto out_cleanup_subreq;
1426 	}
1427 
1428 	nfs_pgio_set_current_mirror(desc, 0);
1429 	if (!nfs_pageio_add_request_mirror(desc, req))
1430 		goto out_failed;
1431 
1432 	return 1;
1433 
1434 out_cleanup_subreq:
1435 	nfs_pageio_cleanup_request(desc, dupreq);
1436 out_failed:
1437 	nfs_pageio_error_cleanup(desc);
1438 	return 0;
1439 }
1440 
1441 /*
1442  * nfs_pageio_complete_mirror - Complete I/O on the current mirror of an
1443  *				nfs_pageio_descriptor
1444  * @desc: pointer to io descriptor
1445  * @mirror_idx: pointer to mirror index
1446  */
nfs_pageio_complete_mirror(struct nfs_pageio_descriptor * desc,u32 mirror_idx)1447 static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc,
1448 				       u32 mirror_idx)
1449 {
1450 	struct nfs_pgio_mirror *mirror;
1451 	u32 restore_idx;
1452 
1453 	restore_idx = nfs_pgio_set_current_mirror(desc, mirror_idx);
1454 	mirror = nfs_pgio_current_mirror(desc);
1455 
1456 	for (;;) {
1457 		nfs_pageio_doio(desc);
1458 		if (desc->pg_error < 0 || !mirror->pg_recoalesce)
1459 			break;
1460 		if (!nfs_do_recoalesce(desc))
1461 			break;
1462 	}
1463 	nfs_pgio_set_current_mirror(desc, restore_idx);
1464 }
1465 
1466 /*
1467  * nfs_pageio_resend - Transfer requests to new descriptor and resend
1468  * @hdr - the pgio header to move request from
1469  * @desc - the pageio descriptor to add requests to
1470  *
1471  * Try to move each request (nfs_page) from @hdr to @desc then attempt
1472  * to send them.
1473  *
1474  * Returns 0 on success and < 0 on error.
1475  */
nfs_pageio_resend(struct nfs_pageio_descriptor * desc,struct nfs_pgio_header * hdr)1476 int nfs_pageio_resend(struct nfs_pageio_descriptor *desc,
1477 		      struct nfs_pgio_header *hdr)
1478 {
1479 	LIST_HEAD(pages);
1480 
1481 	desc->pg_io_completion = hdr->io_completion;
1482 	desc->pg_dreq = hdr->dreq;
1483 	nfs_netfs_set_pageio_descriptor(desc, hdr);
1484 	list_splice_init(&hdr->pages, &pages);
1485 	while (!list_empty(&pages)) {
1486 		struct nfs_page *req = nfs_list_entry(pages.next);
1487 
1488 		if (!nfs_pageio_add_request(desc, req))
1489 			break;
1490 	}
1491 	nfs_pageio_complete(desc);
1492 	if (!list_empty(&pages)) {
1493 		int err = desc->pg_error < 0 ? desc->pg_error : -EIO;
1494 		hdr->completion_ops->error_cleanup(&pages, err);
1495 		nfs_set_pgio_error(hdr, err, hdr->io_start);
1496 		return err;
1497 	}
1498 	return 0;
1499 }
1500 EXPORT_SYMBOL_GPL(nfs_pageio_resend);
1501 
1502 /**
1503  * nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor
1504  * @desc: pointer to io descriptor
1505  */
nfs_pageio_complete(struct nfs_pageio_descriptor * desc)1506 void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
1507 {
1508 	u32 midx;
1509 
1510 	for (midx = 0; midx < desc->pg_mirror_count; midx++)
1511 		nfs_pageio_complete_mirror(desc, midx);
1512 
1513 	if (desc->pg_error < 0)
1514 		nfs_pageio_error_cleanup(desc);
1515 	if (desc->pg_ops->pg_cleanup)
1516 		desc->pg_ops->pg_cleanup(desc);
1517 	nfs_pageio_cleanup_mirroring(desc);
1518 }
1519 
1520 /**
1521  * nfs_pageio_cond_complete - Conditional I/O completion
1522  * @desc: pointer to io descriptor
1523  * @index: page index
1524  *
1525  * It is important to ensure that processes don't try to take locks
1526  * on non-contiguous ranges of pages as that might deadlock. This
1527  * function should be called before attempting to wait on a locked
1528  * nfs_page. It will complete the I/O if the page index 'index'
1529  * is not contiguous with the existing list of pages in 'desc'.
1530  */
nfs_pageio_cond_complete(struct nfs_pageio_descriptor * desc,pgoff_t index)1531 void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
1532 {
1533 	struct nfs_pgio_mirror *mirror;
1534 	struct nfs_page *prev;
1535 	struct folio *folio;
1536 	u32 midx;
1537 
1538 	for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1539 		mirror = nfs_pgio_get_mirror(desc, midx);
1540 		if (!list_empty(&mirror->pg_list)) {
1541 			prev = nfs_list_entry(mirror->pg_list.prev);
1542 			folio = nfs_page_to_folio(prev);
1543 			if (folio) {
1544 				if (index == folio_next_index(folio))
1545 					continue;
1546 			} else if (index == prev->wb_index + 1)
1547 				continue;
1548 			nfs_pageio_complete(desc);
1549 			break;
1550 		}
1551 	}
1552 }
1553 
1554 /*
1555  * nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1)
1556  */
nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor * pgio)1557 void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio)
1558 {
1559 	nfs_pageio_complete(pgio);
1560 }
1561 
nfs_init_nfspagecache(void)1562 int __init nfs_init_nfspagecache(void)
1563 {
1564 	nfs_page_cachep = kmem_cache_create("nfs_page",
1565 					    sizeof(struct nfs_page),
1566 					    0, SLAB_HWCACHE_ALIGN,
1567 					    NULL);
1568 	if (nfs_page_cachep == NULL)
1569 		return -ENOMEM;
1570 
1571 	return 0;
1572 }
1573 
nfs_destroy_nfspagecache(void)1574 void nfs_destroy_nfspagecache(void)
1575 {
1576 	kmem_cache_destroy(nfs_page_cachep);
1577 }
1578 
1579 static const struct rpc_call_ops nfs_pgio_common_ops = {
1580 	.rpc_call_prepare = nfs_pgio_prepare,
1581 	.rpc_call_done = nfs_pgio_result,
1582 	.rpc_release = nfs_pgio_release,
1583 };
1584 
1585 const struct nfs_pageio_ops nfs_pgio_rw_ops = {
1586 	.pg_test = nfs_generic_pg_test,
1587 	.pg_doio = nfs_generic_pg_pgios,
1588 };
1589