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