1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * linux/fs/nfs/write.c
4  *
5  * Write file data over NFS.
6  *
7  * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
8  */
9 
10 #include <linux/types.h>
11 #include <linux/slab.h>
12 #include <linux/mm.h>
13 #include <linux/pagemap.h>
14 #include <linux/file.h>
15 #include <linux/writeback.h>
16 #include <linux/swap.h>
17 #include <linux/migrate.h>
18 
19 #include <linux/sunrpc/clnt.h>
20 #include <linux/nfs_fs.h>
21 #include <linux/nfs_mount.h>
22 #include <linux/nfs_page.h>
23 #include <linux/backing-dev.h>
24 #include <linux/export.h>
25 #include <linux/freezer.h>
26 #include <linux/wait.h>
27 #include <linux/iversion.h>
28 #include <linux/filelock.h>
29 
30 #include <linux/uaccess.h>
31 #include <linux/sched/mm.h>
32 
33 #include "delegation.h"
34 #include "internal.h"
35 #include "iostat.h"
36 #include "nfs4_fs.h"
37 #include "fscache.h"
38 #include "pnfs.h"
39 
40 #include "nfstrace.h"
41 
42 #define NFSDBG_FACILITY		NFSDBG_PAGECACHE
43 
44 #define MIN_POOL_WRITE		(32)
45 #define MIN_POOL_COMMIT		(4)
46 
47 struct nfs_io_completion {
48 	void (*complete)(void *data);
49 	void *data;
50 	struct kref refcount;
51 };
52 
53 /*
54  * Local function declarations
55  */
56 static void nfs_redirty_request(struct nfs_page *req);
57 static const struct rpc_call_ops nfs_commit_ops;
58 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
59 static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
60 static const struct nfs_rw_ops nfs_rw_write_ops;
61 static void nfs_inode_remove_request(struct nfs_page *req);
62 static void nfs_clear_request_commit(struct nfs_commit_info *cinfo,
63 				     struct nfs_page *req);
64 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
65 				      struct inode *inode);
66 static struct nfs_page *
67 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
68 						struct folio *folio);
69 
70 static struct kmem_cache *nfs_wdata_cachep;
71 static mempool_t *nfs_wdata_mempool;
72 static struct kmem_cache *nfs_cdata_cachep;
73 static mempool_t *nfs_commit_mempool;
74 
nfs_commitdata_alloc(void)75 struct nfs_commit_data *nfs_commitdata_alloc(void)
76 {
77 	struct nfs_commit_data *p;
78 
79 	p = kmem_cache_zalloc(nfs_cdata_cachep, nfs_io_gfp_mask());
80 	if (!p) {
81 		p = mempool_alloc(nfs_commit_mempool, GFP_NOWAIT);
82 		if (!p)
83 			return NULL;
84 		memset(p, 0, sizeof(*p));
85 	}
86 	INIT_LIST_HEAD(&p->pages);
87 	return p;
88 }
89 EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
90 
nfs_commit_free(struct nfs_commit_data * p)91 void nfs_commit_free(struct nfs_commit_data *p)
92 {
93 	mempool_free(p, nfs_commit_mempool);
94 }
95 EXPORT_SYMBOL_GPL(nfs_commit_free);
96 
nfs_writehdr_alloc(void)97 static struct nfs_pgio_header *nfs_writehdr_alloc(void)
98 {
99 	struct nfs_pgio_header *p;
100 
101 	p = kmem_cache_zalloc(nfs_wdata_cachep, nfs_io_gfp_mask());
102 	if (!p) {
103 		p = mempool_alloc(nfs_wdata_mempool, GFP_NOWAIT);
104 		if (!p)
105 			return NULL;
106 		memset(p, 0, sizeof(*p));
107 	}
108 	p->rw_mode = FMODE_WRITE;
109 	return p;
110 }
111 
nfs_writehdr_free(struct nfs_pgio_header * hdr)112 static void nfs_writehdr_free(struct nfs_pgio_header *hdr)
113 {
114 	mempool_free(hdr, nfs_wdata_mempool);
115 }
116 
nfs_io_completion_alloc(gfp_t gfp_flags)117 static struct nfs_io_completion *nfs_io_completion_alloc(gfp_t gfp_flags)
118 {
119 	return kmalloc(sizeof(struct nfs_io_completion), gfp_flags);
120 }
121 
nfs_io_completion_init(struct nfs_io_completion * ioc,void (* complete)(void *),void * data)122 static void nfs_io_completion_init(struct nfs_io_completion *ioc,
123 		void (*complete)(void *), void *data)
124 {
125 	ioc->complete = complete;
126 	ioc->data = data;
127 	kref_init(&ioc->refcount);
128 }
129 
nfs_io_completion_release(struct kref * kref)130 static void nfs_io_completion_release(struct kref *kref)
131 {
132 	struct nfs_io_completion *ioc = container_of(kref,
133 			struct nfs_io_completion, refcount);
134 	ioc->complete(ioc->data);
135 	kfree(ioc);
136 }
137 
nfs_io_completion_get(struct nfs_io_completion * ioc)138 static void nfs_io_completion_get(struct nfs_io_completion *ioc)
139 {
140 	if (ioc != NULL)
141 		kref_get(&ioc->refcount);
142 }
143 
nfs_io_completion_put(struct nfs_io_completion * ioc)144 static void nfs_io_completion_put(struct nfs_io_completion *ioc)
145 {
146 	if (ioc != NULL)
147 		kref_put(&ioc->refcount, nfs_io_completion_release);
148 }
149 
150 static void
nfs_page_set_inode_ref(struct nfs_page * req,struct inode * inode)151 nfs_page_set_inode_ref(struct nfs_page *req, struct inode *inode)
152 {
153 	if (!test_and_set_bit(PG_INODE_REF, &req->wb_flags)) {
154 		kref_get(&req->wb_kref);
155 		atomic_long_inc(&NFS_I(inode)->nrequests);
156 	}
157 }
158 
159 static int
nfs_cancel_remove_inode(struct nfs_page * req,struct inode * inode)160 nfs_cancel_remove_inode(struct nfs_page *req, struct inode *inode)
161 {
162 	int ret;
163 
164 	if (!test_bit(PG_REMOVE, &req->wb_flags))
165 		return 0;
166 	ret = nfs_page_group_lock(req);
167 	if (ret)
168 		return ret;
169 	if (test_and_clear_bit(PG_REMOVE, &req->wb_flags))
170 		nfs_page_set_inode_ref(req, inode);
171 	nfs_page_group_unlock(req);
172 	return 0;
173 }
174 
nfs_folio_private_request(struct folio * folio)175 static struct nfs_page *nfs_folio_private_request(struct folio *folio)
176 {
177 	return folio_get_private(folio);
178 }
179 
180 /**
181  * nfs_folio_find_private_request - find head request associated with a folio
182  * @folio: pointer to folio
183  *
184  * must be called while holding the inode lock.
185  *
186  * returns matching head request with reference held, or NULL if not found.
187  */
nfs_folio_find_private_request(struct folio * folio)188 static struct nfs_page *nfs_folio_find_private_request(struct folio *folio)
189 {
190 	struct address_space *mapping = folio_file_mapping(folio);
191 	struct nfs_page *req;
192 
193 	if (!folio_test_private(folio))
194 		return NULL;
195 	spin_lock(&mapping->private_lock);
196 	req = nfs_folio_private_request(folio);
197 	if (req) {
198 		WARN_ON_ONCE(req->wb_head != req);
199 		kref_get(&req->wb_kref);
200 	}
201 	spin_unlock(&mapping->private_lock);
202 	return req;
203 }
204 
nfs_folio_find_swap_request(struct folio * folio)205 static struct nfs_page *nfs_folio_find_swap_request(struct folio *folio)
206 {
207 	struct inode *inode = folio_file_mapping(folio)->host;
208 	struct nfs_inode *nfsi = NFS_I(inode);
209 	struct nfs_page *req = NULL;
210 	if (!folio_test_swapcache(folio))
211 		return NULL;
212 	mutex_lock(&nfsi->commit_mutex);
213 	if (folio_test_swapcache(folio)) {
214 		req = nfs_page_search_commits_for_head_request_locked(nfsi,
215 								      folio);
216 		if (req) {
217 			WARN_ON_ONCE(req->wb_head != req);
218 			kref_get(&req->wb_kref);
219 		}
220 	}
221 	mutex_unlock(&nfsi->commit_mutex);
222 	return req;
223 }
224 
225 /**
226  * nfs_folio_find_head_request - find head request associated with a folio
227  * @folio: pointer to folio
228  *
229  * returns matching head request with reference held, or NULL if not found.
230  */
nfs_folio_find_head_request(struct folio * folio)231 static struct nfs_page *nfs_folio_find_head_request(struct folio *folio)
232 {
233 	struct nfs_page *req;
234 
235 	req = nfs_folio_find_private_request(folio);
236 	if (!req)
237 		req = nfs_folio_find_swap_request(folio);
238 	return req;
239 }
240 
nfs_folio_find_and_lock_request(struct folio * folio)241 static struct nfs_page *nfs_folio_find_and_lock_request(struct folio *folio)
242 {
243 	struct inode *inode = folio_file_mapping(folio)->host;
244 	struct nfs_page *req, *head;
245 	int ret;
246 
247 	for (;;) {
248 		req = nfs_folio_find_head_request(folio);
249 		if (!req)
250 			return req;
251 		head = nfs_page_group_lock_head(req);
252 		if (head != req)
253 			nfs_release_request(req);
254 		if (IS_ERR(head))
255 			return head;
256 		ret = nfs_cancel_remove_inode(head, inode);
257 		if (ret < 0) {
258 			nfs_unlock_and_release_request(head);
259 			return ERR_PTR(ret);
260 		}
261 		/* Ensure that nobody removed the request before we locked it */
262 		if (head == nfs_folio_private_request(folio))
263 			break;
264 		if (folio_test_swapcache(folio))
265 			break;
266 		nfs_unlock_and_release_request(head);
267 	}
268 	return head;
269 }
270 
271 /* Adjust the file length if we're writing beyond the end */
nfs_grow_file(struct folio * folio,unsigned int offset,unsigned int count)272 static void nfs_grow_file(struct folio *folio, unsigned int offset,
273 			  unsigned int count)
274 {
275 	struct inode *inode = folio_file_mapping(folio)->host;
276 	loff_t end, i_size;
277 	pgoff_t end_index;
278 
279 	spin_lock(&inode->i_lock);
280 	i_size = i_size_read(inode);
281 	end_index = ((i_size - 1) >> folio_shift(folio)) << folio_order(folio);
282 	if (i_size > 0 && folio_index(folio) < end_index)
283 		goto out;
284 	end = folio_file_pos(folio) + (loff_t)offset + (loff_t)count;
285 	if (i_size >= end)
286 		goto out;
287 	trace_nfs_size_grow(inode, end);
288 	i_size_write(inode, end);
289 	NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;
290 	nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
291 out:
292 	spin_unlock(&inode->i_lock);
293 	nfs_fscache_invalidate(inode, 0);
294 }
295 
296 /* A writeback failed: mark the page as bad, and invalidate the page cache */
nfs_set_pageerror(struct address_space * mapping)297 static void nfs_set_pageerror(struct address_space *mapping)
298 {
299 	struct inode *inode = mapping->host;
300 
301 	nfs_zap_mapping(mapping->host, mapping);
302 	/* Force file size revalidation */
303 	spin_lock(&inode->i_lock);
304 	nfs_set_cache_invalid(inode, NFS_INO_REVAL_FORCED |
305 					     NFS_INO_INVALID_CHANGE |
306 					     NFS_INO_INVALID_SIZE);
307 	spin_unlock(&inode->i_lock);
308 }
309 
nfs_mapping_set_error(struct folio * folio,int error)310 static void nfs_mapping_set_error(struct folio *folio, int error)
311 {
312 	struct address_space *mapping = folio_file_mapping(folio);
313 
314 	folio_set_error(folio);
315 	filemap_set_wb_err(mapping, error);
316 	if (mapping->host)
317 		errseq_set(&mapping->host->i_sb->s_wb_err,
318 			   error == -ENOSPC ? -ENOSPC : -EIO);
319 	nfs_set_pageerror(mapping);
320 }
321 
322 /*
323  * nfs_page_group_search_locked
324  * @head - head request of page group
325  * @page_offset - offset into page
326  *
327  * Search page group with head @head to find a request that contains the
328  * page offset @page_offset.
329  *
330  * Returns a pointer to the first matching nfs request, or NULL if no
331  * match is found.
332  *
333  * Must be called with the page group lock held
334  */
335 static struct nfs_page *
nfs_page_group_search_locked(struct nfs_page * head,unsigned int page_offset)336 nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset)
337 {
338 	struct nfs_page *req;
339 
340 	req = head;
341 	do {
342 		if (page_offset >= req->wb_pgbase &&
343 		    page_offset < (req->wb_pgbase + req->wb_bytes))
344 			return req;
345 
346 		req = req->wb_this_page;
347 	} while (req != head);
348 
349 	return NULL;
350 }
351 
352 /*
353  * nfs_page_group_covers_page
354  * @head - head request of page group
355  *
356  * Return true if the page group with head @head covers the whole page,
357  * returns false otherwise
358  */
nfs_page_group_covers_page(struct nfs_page * req)359 static bool nfs_page_group_covers_page(struct nfs_page *req)
360 {
361 	unsigned int len = nfs_folio_length(nfs_page_to_folio(req));
362 	struct nfs_page *tmp;
363 	unsigned int pos = 0;
364 
365 	nfs_page_group_lock(req);
366 
367 	for (;;) {
368 		tmp = nfs_page_group_search_locked(req->wb_head, pos);
369 		if (!tmp)
370 			break;
371 		pos = tmp->wb_pgbase + tmp->wb_bytes;
372 	}
373 
374 	nfs_page_group_unlock(req);
375 	return pos >= len;
376 }
377 
378 /* We can set the PG_uptodate flag if we see that a write request
379  * covers the full page.
380  */
nfs_mark_uptodate(struct nfs_page * req)381 static void nfs_mark_uptodate(struct nfs_page *req)
382 {
383 	struct folio *folio = nfs_page_to_folio(req);
384 
385 	if (folio_test_uptodate(folio))
386 		return;
387 	if (!nfs_page_group_covers_page(req))
388 		return;
389 	folio_mark_uptodate(folio);
390 }
391 
wb_priority(struct writeback_control * wbc)392 static int wb_priority(struct writeback_control *wbc)
393 {
394 	int ret = 0;
395 
396 	if (wbc->sync_mode == WB_SYNC_ALL)
397 		ret = FLUSH_COND_STABLE;
398 	return ret;
399 }
400 
401 /*
402  * NFS congestion control
403  */
404 
405 int nfs_congestion_kb;
406 
407 #define NFS_CONGESTION_ON_THRESH 	(nfs_congestion_kb >> (PAGE_SHIFT-10))
408 #define NFS_CONGESTION_OFF_THRESH	\
409 	(NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
410 
nfs_folio_set_writeback(struct folio * folio)411 static void nfs_folio_set_writeback(struct folio *folio)
412 {
413 	struct nfs_server *nfss = NFS_SERVER(folio_file_mapping(folio)->host);
414 
415 	folio_start_writeback(folio);
416 	if (atomic_long_inc_return(&nfss->writeback) > NFS_CONGESTION_ON_THRESH)
417 		nfss->write_congested = 1;
418 }
419 
nfs_folio_end_writeback(struct folio * folio)420 static void nfs_folio_end_writeback(struct folio *folio)
421 {
422 	struct nfs_server *nfss = NFS_SERVER(folio_file_mapping(folio)->host);
423 
424 	folio_end_writeback(folio);
425 	if (atomic_long_dec_return(&nfss->writeback) <
426 	    NFS_CONGESTION_OFF_THRESH)
427 		nfss->write_congested = 0;
428 }
429 
nfs_page_end_writeback(struct nfs_page * req)430 static void nfs_page_end_writeback(struct nfs_page *req)
431 {
432 	if (nfs_page_group_sync_on_bit(req, PG_WB_END)) {
433 		nfs_unlock_request(req);
434 		nfs_folio_end_writeback(nfs_page_to_folio(req));
435 	} else
436 		nfs_unlock_request(req);
437 }
438 
439 /*
440  * nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests
441  *
442  * @destroy_list - request list (using wb_this_page) terminated by @old_head
443  * @old_head - the old head of the list
444  *
445  * All subrequests must be locked and removed from all lists, so at this point
446  * they are only "active" in this function, and possibly in nfs_wait_on_request
447  * with a reference held by some other context.
448  */
449 static void
nfs_destroy_unlinked_subrequests(struct nfs_page * destroy_list,struct nfs_page * old_head,struct inode * inode)450 nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
451 				 struct nfs_page *old_head,
452 				 struct inode *inode)
453 {
454 	while (destroy_list) {
455 		struct nfs_page *subreq = destroy_list;
456 
457 		destroy_list = (subreq->wb_this_page == old_head) ?
458 				   NULL : subreq->wb_this_page;
459 
460 		/* Note: lock subreq in order to change subreq->wb_head */
461 		nfs_page_set_headlock(subreq);
462 		WARN_ON_ONCE(old_head != subreq->wb_head);
463 
464 		/* make sure old group is not used */
465 		subreq->wb_this_page = subreq;
466 		subreq->wb_head = subreq;
467 
468 		clear_bit(PG_REMOVE, &subreq->wb_flags);
469 
470 		/* Note: races with nfs_page_group_destroy() */
471 		if (!kref_read(&subreq->wb_kref)) {
472 			/* Check if we raced with nfs_page_group_destroy() */
473 			if (test_and_clear_bit(PG_TEARDOWN, &subreq->wb_flags)) {
474 				nfs_page_clear_headlock(subreq);
475 				nfs_free_request(subreq);
476 			} else
477 				nfs_page_clear_headlock(subreq);
478 			continue;
479 		}
480 		nfs_page_clear_headlock(subreq);
481 
482 		nfs_release_request(old_head);
483 
484 		if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) {
485 			nfs_release_request(subreq);
486 			atomic_long_dec(&NFS_I(inode)->nrequests);
487 		}
488 
489 		/* subreq is now totally disconnected from page group or any
490 		 * write / commit lists. last chance to wake any waiters */
491 		nfs_unlock_and_release_request(subreq);
492 	}
493 }
494 
495 /*
496  * nfs_join_page_group - destroy subrequests of the head req
497  * @head: the page used to lookup the "page group" of nfs_page structures
498  * @inode: Inode to which the request belongs.
499  *
500  * This function joins all sub requests to the head request by first
501  * locking all requests in the group, cancelling any pending operations
502  * and finally updating the head request to cover the whole range covered by
503  * the (former) group.  All subrequests are removed from any write or commit
504  * lists, unlinked from the group and destroyed.
505  */
nfs_join_page_group(struct nfs_page * head,struct nfs_commit_info * cinfo,struct inode * inode)506 void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo,
507 			 struct inode *inode)
508 {
509 	struct nfs_page *subreq;
510 	struct nfs_page *destroy_list = NULL;
511 	unsigned int pgbase, off, bytes;
512 
513 	pgbase = head->wb_pgbase;
514 	bytes = head->wb_bytes;
515 	off = head->wb_offset;
516 	for (subreq = head->wb_this_page; subreq != head;
517 			subreq = subreq->wb_this_page) {
518 		/* Subrequests should always form a contiguous range */
519 		if (pgbase > subreq->wb_pgbase) {
520 			off -= pgbase - subreq->wb_pgbase;
521 			bytes += pgbase - subreq->wb_pgbase;
522 			pgbase = subreq->wb_pgbase;
523 		}
524 		bytes = max(subreq->wb_pgbase + subreq->wb_bytes
525 				- pgbase, bytes);
526 	}
527 
528 	/* Set the head request's range to cover the former page group */
529 	head->wb_pgbase = pgbase;
530 	head->wb_bytes = bytes;
531 	head->wb_offset = off;
532 
533 	/* Now that all requests are locked, make sure they aren't on any list.
534 	 * Commit list removal accounting is done after locks are dropped */
535 	subreq = head;
536 	do {
537 		nfs_clear_request_commit(cinfo, subreq);
538 		subreq = subreq->wb_this_page;
539 	} while (subreq != head);
540 
541 	/* unlink subrequests from head, destroy them later */
542 	if (head->wb_this_page != head) {
543 		/* destroy list will be terminated by head */
544 		destroy_list = head->wb_this_page;
545 		head->wb_this_page = head;
546 	}
547 
548 	nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
549 }
550 
551 /*
552  * nfs_lock_and_join_requests - join all subreqs to the head req
553  * @folio: the folio used to lookup the "page group" of nfs_page structures
554  *
555  * This function joins all sub requests to the head request by first
556  * locking all requests in the group, cancelling any pending operations
557  * and finally updating the head request to cover the whole range covered by
558  * the (former) group.  All subrequests are removed from any write or commit
559  * lists, unlinked from the group and destroyed.
560  *
561  * Returns a locked, referenced pointer to the head request - which after
562  * this call is guaranteed to be the only request associated with the page.
563  * Returns NULL if no requests are found for @folio, or a ERR_PTR if an
564  * error was encountered.
565  */
nfs_lock_and_join_requests(struct folio * folio)566 static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio)
567 {
568 	struct inode *inode = folio_file_mapping(folio)->host;
569 	struct nfs_page *head;
570 	struct nfs_commit_info cinfo;
571 	int ret;
572 
573 	nfs_init_cinfo_from_inode(&cinfo, inode);
574 	/*
575 	 * A reference is taken only on the head request which acts as a
576 	 * reference to the whole page group - the group will not be destroyed
577 	 * until the head reference is released.
578 	 */
579 	head = nfs_folio_find_and_lock_request(folio);
580 	if (IS_ERR_OR_NULL(head))
581 		return head;
582 
583 	/* lock each request in the page group */
584 	ret = nfs_page_group_lock_subrequests(head);
585 	if (ret < 0) {
586 		nfs_unlock_and_release_request(head);
587 		return ERR_PTR(ret);
588 	}
589 
590 	nfs_join_page_group(head, &cinfo, inode);
591 
592 	return head;
593 }
594 
nfs_write_error(struct nfs_page * req,int error)595 static void nfs_write_error(struct nfs_page *req, int error)
596 {
597 	trace_nfs_write_error(nfs_page_to_inode(req), req, error);
598 	nfs_mapping_set_error(nfs_page_to_folio(req), error);
599 	nfs_inode_remove_request(req);
600 	nfs_page_end_writeback(req);
601 	nfs_release_request(req);
602 }
603 
604 /*
605  * Find an associated nfs write request, and prepare to flush it out
606  * May return an error if the user signalled nfs_wait_on_request().
607  */
nfs_page_async_flush(struct folio * folio,struct writeback_control * wbc,struct nfs_pageio_descriptor * pgio)608 static int nfs_page_async_flush(struct folio *folio,
609 				struct writeback_control *wbc,
610 				struct nfs_pageio_descriptor *pgio)
611 {
612 	struct nfs_page *req;
613 	int ret = 0;
614 
615 	req = nfs_lock_and_join_requests(folio);
616 	if (!req)
617 		goto out;
618 	ret = PTR_ERR(req);
619 	if (IS_ERR(req))
620 		goto out;
621 
622 	nfs_folio_set_writeback(folio);
623 	WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
624 
625 	/* If there is a fatal error that covers this write, just exit */
626 	ret = pgio->pg_error;
627 	if (nfs_error_is_fatal_on_server(ret))
628 		goto out_launder;
629 
630 	ret = 0;
631 	if (!nfs_pageio_add_request(pgio, req)) {
632 		ret = pgio->pg_error;
633 		/*
634 		 * Remove the problematic req upon fatal errors on the server
635 		 */
636 		if (nfs_error_is_fatal_on_server(ret))
637 			goto out_launder;
638 		if (wbc->sync_mode == WB_SYNC_NONE)
639 			ret = AOP_WRITEPAGE_ACTIVATE;
640 		folio_redirty_for_writepage(wbc, folio);
641 		nfs_redirty_request(req);
642 		pgio->pg_error = 0;
643 	} else
644 		nfs_add_stats(folio_file_mapping(folio)->host,
645 			      NFSIOS_WRITEPAGES, 1);
646 out:
647 	return ret;
648 out_launder:
649 	nfs_write_error(req, ret);
650 	return 0;
651 }
652 
nfs_do_writepage(struct folio * folio,struct writeback_control * wbc,struct nfs_pageio_descriptor * pgio)653 static int nfs_do_writepage(struct folio *folio, struct writeback_control *wbc,
654 			    struct nfs_pageio_descriptor *pgio)
655 {
656 	nfs_pageio_cond_complete(pgio, folio_index(folio));
657 	return nfs_page_async_flush(folio, wbc, pgio);
658 }
659 
660 /*
661  * Write an mmapped page to the server.
662  */
nfs_writepage_locked(struct folio * folio,struct writeback_control * wbc)663 static int nfs_writepage_locked(struct folio *folio,
664 				struct writeback_control *wbc)
665 {
666 	struct nfs_pageio_descriptor pgio;
667 	struct inode *inode = folio_file_mapping(folio)->host;
668 	int err;
669 
670 	if (wbc->sync_mode == WB_SYNC_NONE &&
671 	    NFS_SERVER(inode)->write_congested) {
672 		folio_redirty_for_writepage(wbc, folio);
673 		return AOP_WRITEPAGE_ACTIVATE;
674 	}
675 
676 	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
677 	nfs_pageio_init_write(&pgio, inode, 0, false,
678 			      &nfs_async_write_completion_ops);
679 	err = nfs_do_writepage(folio, wbc, &pgio);
680 	pgio.pg_error = 0;
681 	nfs_pageio_complete(&pgio);
682 	return err;
683 }
684 
nfs_writepage(struct page * page,struct writeback_control * wbc)685 int nfs_writepage(struct page *page, struct writeback_control *wbc)
686 {
687 	struct folio *folio = page_folio(page);
688 	int ret;
689 
690 	ret = nfs_writepage_locked(folio, wbc);
691 	if (ret != AOP_WRITEPAGE_ACTIVATE)
692 		unlock_page(page);
693 	return ret;
694 }
695 
nfs_writepages_callback(struct folio * folio,struct writeback_control * wbc,void * data)696 static int nfs_writepages_callback(struct folio *folio,
697 				   struct writeback_control *wbc, void *data)
698 {
699 	int ret;
700 
701 	ret = nfs_do_writepage(folio, wbc, data);
702 	if (ret != AOP_WRITEPAGE_ACTIVATE)
703 		folio_unlock(folio);
704 	return ret;
705 }
706 
nfs_io_completion_commit(void * inode)707 static void nfs_io_completion_commit(void *inode)
708 {
709 	nfs_commit_inode(inode, 0);
710 }
711 
nfs_writepages(struct address_space * mapping,struct writeback_control * wbc)712 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
713 {
714 	struct inode *inode = mapping->host;
715 	struct nfs_pageio_descriptor pgio;
716 	struct nfs_io_completion *ioc = NULL;
717 	unsigned int mntflags = NFS_SERVER(inode)->flags;
718 	int priority = 0;
719 	int err;
720 
721 	if (wbc->sync_mode == WB_SYNC_NONE &&
722 	    NFS_SERVER(inode)->write_congested)
723 		return 0;
724 
725 	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
726 
727 	if (!(mntflags & NFS_MOUNT_WRITE_EAGER) || wbc->for_kupdate ||
728 	    wbc->for_background || wbc->for_sync || wbc->for_reclaim) {
729 		ioc = nfs_io_completion_alloc(GFP_KERNEL);
730 		if (ioc)
731 			nfs_io_completion_init(ioc, nfs_io_completion_commit,
732 					       inode);
733 		priority = wb_priority(wbc);
734 	}
735 
736 	do {
737 		nfs_pageio_init_write(&pgio, inode, priority, false,
738 				      &nfs_async_write_completion_ops);
739 		pgio.pg_io_completion = ioc;
740 		err = write_cache_pages(mapping, wbc, nfs_writepages_callback,
741 					&pgio);
742 		pgio.pg_error = 0;
743 		nfs_pageio_complete(&pgio);
744 	} while (err < 0 && !nfs_error_is_fatal(err));
745 	nfs_io_completion_put(ioc);
746 
747 	if (err < 0)
748 		goto out_err;
749 	return 0;
750 out_err:
751 	return err;
752 }
753 
754 /*
755  * Insert a write request into an inode
756  */
nfs_inode_add_request(struct nfs_page * req)757 static void nfs_inode_add_request(struct nfs_page *req)
758 {
759 	struct folio *folio = nfs_page_to_folio(req);
760 	struct address_space *mapping = folio_file_mapping(folio);
761 	struct nfs_inode *nfsi = NFS_I(mapping->host);
762 
763 	WARN_ON_ONCE(req->wb_this_page != req);
764 
765 	/* Lock the request! */
766 	nfs_lock_request(req);
767 
768 	/*
769 	 * Swap-space should not get truncated. Hence no need to plug the race
770 	 * with invalidate/truncate.
771 	 */
772 	spin_lock(&mapping->private_lock);
773 	if (likely(!folio_test_swapcache(folio))) {
774 		set_bit(PG_MAPPED, &req->wb_flags);
775 		folio_set_private(folio);
776 		folio->private = req;
777 	}
778 	spin_unlock(&mapping->private_lock);
779 	atomic_long_inc(&nfsi->nrequests);
780 	/* this a head request for a page group - mark it as having an
781 	 * extra reference so sub groups can follow suit.
782 	 * This flag also informs pgio layer when to bump nrequests when
783 	 * adding subrequests. */
784 	WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
785 	kref_get(&req->wb_kref);
786 }
787 
788 /*
789  * Remove a write request from an inode
790  */
nfs_inode_remove_request(struct nfs_page * req)791 static void nfs_inode_remove_request(struct nfs_page *req)
792 {
793 	struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req));
794 
795 	if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
796 		struct folio *folio = nfs_page_to_folio(req->wb_head);
797 		struct address_space *mapping = folio_file_mapping(folio);
798 
799 		spin_lock(&mapping->private_lock);
800 		if (likely(folio && !folio_test_swapcache(folio))) {
801 			folio->private = NULL;
802 			folio_clear_private(folio);
803 			clear_bit(PG_MAPPED, &req->wb_head->wb_flags);
804 		}
805 		spin_unlock(&mapping->private_lock);
806 	}
807 
808 	if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) {
809 		atomic_long_dec(&nfsi->nrequests);
810 		nfs_release_request(req);
811 	}
812 }
813 
nfs_mark_request_dirty(struct nfs_page * req)814 static void nfs_mark_request_dirty(struct nfs_page *req)
815 {
816 	struct folio *folio = nfs_page_to_folio(req);
817 	if (folio)
818 		filemap_dirty_folio(folio_mapping(folio), folio);
819 }
820 
821 /*
822  * nfs_page_search_commits_for_head_request_locked
823  *
824  * Search through commit lists on @inode for the head request for @folio.
825  * Must be called while holding the inode (which is cinfo) lock.
826  *
827  * Returns the head request if found, or NULL if not found.
828  */
829 static struct nfs_page *
nfs_page_search_commits_for_head_request_locked(struct nfs_inode * nfsi,struct folio * folio)830 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
831 						struct folio *folio)
832 {
833 	struct nfs_page *freq, *t;
834 	struct nfs_commit_info cinfo;
835 	struct inode *inode = &nfsi->vfs_inode;
836 
837 	nfs_init_cinfo_from_inode(&cinfo, inode);
838 
839 	/* search through pnfs commit lists */
840 	freq = pnfs_search_commit_reqs(inode, &cinfo, folio);
841 	if (freq)
842 		return freq->wb_head;
843 
844 	/* Linearly search the commit list for the correct request */
845 	list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) {
846 		if (nfs_page_to_folio(freq) == folio)
847 			return freq->wb_head;
848 	}
849 
850 	return NULL;
851 }
852 
853 /**
854  * nfs_request_add_commit_list_locked - add request to a commit list
855  * @req: pointer to a struct nfs_page
856  * @dst: commit list head
857  * @cinfo: holds list lock and accounting info
858  *
859  * This sets the PG_CLEAN bit, updates the cinfo count of
860  * number of outstanding requests requiring a commit as well as
861  * the MM page stats.
862  *
863  * The caller must hold NFS_I(cinfo->inode)->commit_mutex, and the
864  * nfs_page lock.
865  */
866 void
nfs_request_add_commit_list_locked(struct nfs_page * req,struct list_head * dst,struct nfs_commit_info * cinfo)867 nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
868 			    struct nfs_commit_info *cinfo)
869 {
870 	set_bit(PG_CLEAN, &req->wb_flags);
871 	nfs_list_add_request(req, dst);
872 	atomic_long_inc(&cinfo->mds->ncommit);
873 }
874 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
875 
876 /**
877  * nfs_request_add_commit_list - add request to a commit list
878  * @req: pointer to a struct nfs_page
879  * @cinfo: holds list lock and accounting info
880  *
881  * This sets the PG_CLEAN bit, updates the cinfo count of
882  * number of outstanding requests requiring a commit as well as
883  * the MM page stats.
884  *
885  * The caller must _not_ hold the cinfo->lock, but must be
886  * holding the nfs_page lock.
887  */
888 void
nfs_request_add_commit_list(struct nfs_page * req,struct nfs_commit_info * cinfo)889 nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
890 {
891 	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
892 	nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
893 	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
894 	nfs_folio_mark_unstable(nfs_page_to_folio(req), cinfo);
895 }
896 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
897 
898 /**
899  * nfs_request_remove_commit_list - Remove request from a commit list
900  * @req: pointer to a nfs_page
901  * @cinfo: holds list lock and accounting info
902  *
903  * This clears the PG_CLEAN bit, and updates the cinfo's count of
904  * number of outstanding requests requiring a commit
905  * It does not update the MM page stats.
906  *
907  * The caller _must_ hold the cinfo->lock and the nfs_page lock.
908  */
909 void
nfs_request_remove_commit_list(struct nfs_page * req,struct nfs_commit_info * cinfo)910 nfs_request_remove_commit_list(struct nfs_page *req,
911 			       struct nfs_commit_info *cinfo)
912 {
913 	if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
914 		return;
915 	nfs_list_remove_request(req);
916 	atomic_long_dec(&cinfo->mds->ncommit);
917 }
918 EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
919 
nfs_init_cinfo_from_inode(struct nfs_commit_info * cinfo,struct inode * inode)920 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
921 				      struct inode *inode)
922 {
923 	cinfo->inode = inode;
924 	cinfo->mds = &NFS_I(inode)->commit_info;
925 	cinfo->ds = pnfs_get_ds_info(inode);
926 	cinfo->dreq = NULL;
927 	cinfo->completion_ops = &nfs_commit_completion_ops;
928 }
929 
nfs_init_cinfo(struct nfs_commit_info * cinfo,struct inode * inode,struct nfs_direct_req * dreq)930 void nfs_init_cinfo(struct nfs_commit_info *cinfo,
931 		    struct inode *inode,
932 		    struct nfs_direct_req *dreq)
933 {
934 	if (dreq)
935 		nfs_init_cinfo_from_dreq(cinfo, dreq);
936 	else
937 		nfs_init_cinfo_from_inode(cinfo, inode);
938 }
939 EXPORT_SYMBOL_GPL(nfs_init_cinfo);
940 
941 /*
942  * Add a request to the inode's commit list.
943  */
944 void
nfs_mark_request_commit(struct nfs_page * req,struct pnfs_layout_segment * lseg,struct nfs_commit_info * cinfo,u32 ds_commit_idx)945 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
946 			struct nfs_commit_info *cinfo, u32 ds_commit_idx)
947 {
948 	if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx))
949 		return;
950 	nfs_request_add_commit_list(req, cinfo);
951 }
952 
nfs_folio_clear_commit(struct folio * folio)953 static void nfs_folio_clear_commit(struct folio *folio)
954 {
955 	if (folio) {
956 		long nr = folio_nr_pages(folio);
957 
958 		node_stat_mod_folio(folio, NR_WRITEBACK, -nr);
959 		wb_stat_mod(&inode_to_bdi(folio_file_mapping(folio)->host)->wb,
960 			    WB_WRITEBACK, -nr);
961 	}
962 }
963 
964 /* Called holding the request lock on @req */
nfs_clear_request_commit(struct nfs_commit_info * cinfo,struct nfs_page * req)965 static void nfs_clear_request_commit(struct nfs_commit_info *cinfo,
966 				     struct nfs_page *req)
967 {
968 	if (test_bit(PG_CLEAN, &req->wb_flags)) {
969 		struct nfs_open_context *ctx = nfs_req_openctx(req);
970 		struct inode *inode = d_inode(ctx->dentry);
971 
972 		mutex_lock(&NFS_I(inode)->commit_mutex);
973 		if (!pnfs_clear_request_commit(req, cinfo)) {
974 			nfs_request_remove_commit_list(req, cinfo);
975 		}
976 		mutex_unlock(&NFS_I(inode)->commit_mutex);
977 		nfs_folio_clear_commit(nfs_page_to_folio(req));
978 	}
979 }
980 
nfs_write_need_commit(struct nfs_pgio_header * hdr)981 int nfs_write_need_commit(struct nfs_pgio_header *hdr)
982 {
983 	if (hdr->verf.committed == NFS_DATA_SYNC)
984 		return hdr->lseg == NULL;
985 	return hdr->verf.committed != NFS_FILE_SYNC;
986 }
987 
nfs_async_write_init(struct nfs_pgio_header * hdr)988 static void nfs_async_write_init(struct nfs_pgio_header *hdr)
989 {
990 	nfs_io_completion_get(hdr->io_completion);
991 }
992 
nfs_write_completion(struct nfs_pgio_header * hdr)993 static void nfs_write_completion(struct nfs_pgio_header *hdr)
994 {
995 	struct nfs_commit_info cinfo;
996 	unsigned long bytes = 0;
997 
998 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
999 		goto out;
1000 	nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
1001 	while (!list_empty(&hdr->pages)) {
1002 		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
1003 
1004 		bytes += req->wb_bytes;
1005 		nfs_list_remove_request(req);
1006 		if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
1007 		    (hdr->good_bytes < bytes)) {
1008 			trace_nfs_comp_error(hdr->inode, req, hdr->error);
1009 			nfs_mapping_set_error(nfs_page_to_folio(req),
1010 					      hdr->error);
1011 			goto remove_req;
1012 		}
1013 		if (nfs_write_need_commit(hdr)) {
1014 			/* Reset wb_nio, since the write was successful. */
1015 			req->wb_nio = 0;
1016 			memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
1017 			nfs_mark_request_commit(req, hdr->lseg, &cinfo,
1018 				hdr->pgio_mirror_idx);
1019 			goto next;
1020 		}
1021 remove_req:
1022 		nfs_inode_remove_request(req);
1023 next:
1024 		nfs_page_end_writeback(req);
1025 		nfs_release_request(req);
1026 	}
1027 out:
1028 	nfs_io_completion_put(hdr->io_completion);
1029 	hdr->release(hdr);
1030 }
1031 
1032 unsigned long
nfs_reqs_to_commit(struct nfs_commit_info * cinfo)1033 nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
1034 {
1035 	return atomic_long_read(&cinfo->mds->ncommit);
1036 }
1037 
1038 /* NFS_I(cinfo->inode)->commit_mutex held by caller */
1039 int
nfs_scan_commit_list(struct list_head * src,struct list_head * dst,struct nfs_commit_info * cinfo,int max)1040 nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
1041 		     struct nfs_commit_info *cinfo, int max)
1042 {
1043 	struct nfs_page *req, *tmp;
1044 	int ret = 0;
1045 
1046 	list_for_each_entry_safe(req, tmp, src, wb_list) {
1047 		kref_get(&req->wb_kref);
1048 		if (!nfs_lock_request(req)) {
1049 			nfs_release_request(req);
1050 			continue;
1051 		}
1052 		nfs_request_remove_commit_list(req, cinfo);
1053 		clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
1054 		nfs_list_add_request(req, dst);
1055 		ret++;
1056 		if ((ret == max) && !cinfo->dreq)
1057 			break;
1058 		cond_resched();
1059 	}
1060 	return ret;
1061 }
1062 EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
1063 
1064 /*
1065  * nfs_scan_commit - Scan an inode for commit requests
1066  * @inode: NFS inode to scan
1067  * @dst: mds destination list
1068  * @cinfo: mds and ds lists of reqs ready to commit
1069  *
1070  * Moves requests from the inode's 'commit' request list.
1071  * The requests are *not* checked to ensure that they form a contiguous set.
1072  */
1073 int
nfs_scan_commit(struct inode * inode,struct list_head * dst,struct nfs_commit_info * cinfo)1074 nfs_scan_commit(struct inode *inode, struct list_head *dst,
1075 		struct nfs_commit_info *cinfo)
1076 {
1077 	int ret = 0;
1078 
1079 	if (!atomic_long_read(&cinfo->mds->ncommit))
1080 		return 0;
1081 	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
1082 	if (atomic_long_read(&cinfo->mds->ncommit) > 0) {
1083 		const int max = INT_MAX;
1084 
1085 		ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
1086 					   cinfo, max);
1087 		ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
1088 	}
1089 	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
1090 	return ret;
1091 }
1092 
1093 /*
1094  * Search for an existing write request, and attempt to update
1095  * it to reflect a new dirty region on a given page.
1096  *
1097  * If the attempt fails, then the existing request is flushed out
1098  * to disk.
1099  */
nfs_try_to_update_request(struct folio * folio,unsigned int offset,unsigned int bytes)1100 static struct nfs_page *nfs_try_to_update_request(struct folio *folio,
1101 						  unsigned int offset,
1102 						  unsigned int bytes)
1103 {
1104 	struct nfs_page *req;
1105 	unsigned int rqend;
1106 	unsigned int end;
1107 	int error;
1108 
1109 	end = offset + bytes;
1110 
1111 	req = nfs_lock_and_join_requests(folio);
1112 	if (IS_ERR_OR_NULL(req))
1113 		return req;
1114 
1115 	rqend = req->wb_offset + req->wb_bytes;
1116 	/*
1117 	 * Tell the caller to flush out the request if
1118 	 * the offsets are non-contiguous.
1119 	 * Note: nfs_flush_incompatible() will already
1120 	 * have flushed out requests having wrong owners.
1121 	 */
1122 	if (offset > rqend || end < req->wb_offset)
1123 		goto out_flushme;
1124 
1125 	/* Okay, the request matches. Update the region */
1126 	if (offset < req->wb_offset) {
1127 		req->wb_offset = offset;
1128 		req->wb_pgbase = offset;
1129 	}
1130 	if (end > rqend)
1131 		req->wb_bytes = end - req->wb_offset;
1132 	else
1133 		req->wb_bytes = rqend - req->wb_offset;
1134 	req->wb_nio = 0;
1135 	return req;
1136 out_flushme:
1137 	/*
1138 	 * Note: we mark the request dirty here because
1139 	 * nfs_lock_and_join_requests() cannot preserve
1140 	 * commit flags, so we have to replay the write.
1141 	 */
1142 	nfs_mark_request_dirty(req);
1143 	nfs_unlock_and_release_request(req);
1144 	error = nfs_wb_folio(folio_file_mapping(folio)->host, folio);
1145 	return (error < 0) ? ERR_PTR(error) : NULL;
1146 }
1147 
1148 /*
1149  * Try to update an existing write request, or create one if there is none.
1150  *
1151  * Note: Should always be called with the Page Lock held to prevent races
1152  * if we have to add a new request. Also assumes that the caller has
1153  * already called nfs_flush_incompatible() if necessary.
1154  */
nfs_setup_write_request(struct nfs_open_context * ctx,struct folio * folio,unsigned int offset,unsigned int bytes)1155 static struct nfs_page *nfs_setup_write_request(struct nfs_open_context *ctx,
1156 						struct folio *folio,
1157 						unsigned int offset,
1158 						unsigned int bytes)
1159 {
1160 	struct nfs_page *req;
1161 
1162 	req = nfs_try_to_update_request(folio, offset, bytes);
1163 	if (req != NULL)
1164 		goto out;
1165 	req = nfs_page_create_from_folio(ctx, folio, offset, bytes);
1166 	if (IS_ERR(req))
1167 		goto out;
1168 	nfs_inode_add_request(req);
1169 out:
1170 	return req;
1171 }
1172 
nfs_writepage_setup(struct nfs_open_context * ctx,struct folio * folio,unsigned int offset,unsigned int count)1173 static int nfs_writepage_setup(struct nfs_open_context *ctx,
1174 			       struct folio *folio, unsigned int offset,
1175 			       unsigned int count)
1176 {
1177 	struct nfs_page *req;
1178 
1179 	req = nfs_setup_write_request(ctx, folio, offset, count);
1180 	if (IS_ERR(req))
1181 		return PTR_ERR(req);
1182 	/* Update file length */
1183 	nfs_grow_file(folio, offset, count);
1184 	nfs_mark_uptodate(req);
1185 	nfs_mark_request_dirty(req);
1186 	nfs_unlock_and_release_request(req);
1187 	return 0;
1188 }
1189 
nfs_flush_incompatible(struct file * file,struct folio * folio)1190 int nfs_flush_incompatible(struct file *file, struct folio *folio)
1191 {
1192 	struct nfs_open_context *ctx = nfs_file_open_context(file);
1193 	struct nfs_lock_context *l_ctx;
1194 	struct file_lock_context *flctx = locks_inode_context(file_inode(file));
1195 	struct nfs_page	*req;
1196 	int do_flush, status;
1197 	/*
1198 	 * Look for a request corresponding to this page. If there
1199 	 * is one, and it belongs to another file, we flush it out
1200 	 * before we try to copy anything into the page. Do this
1201 	 * due to the lack of an ACCESS-type call in NFSv2.
1202 	 * Also do the same if we find a request from an existing
1203 	 * dropped page.
1204 	 */
1205 	do {
1206 		req = nfs_folio_find_head_request(folio);
1207 		if (req == NULL)
1208 			return 0;
1209 		l_ctx = req->wb_lock_context;
1210 		do_flush = nfs_page_to_folio(req) != folio ||
1211 			   !nfs_match_open_context(nfs_req_openctx(req), ctx);
1212 		if (l_ctx && flctx &&
1213 		    !(list_empty_careful(&flctx->flc_posix) &&
1214 		      list_empty_careful(&flctx->flc_flock))) {
1215 			do_flush |= l_ctx->lockowner != current->files;
1216 		}
1217 		nfs_release_request(req);
1218 		if (!do_flush)
1219 			return 0;
1220 		status = nfs_wb_folio(folio_file_mapping(folio)->host, folio);
1221 	} while (status == 0);
1222 	return status;
1223 }
1224 
1225 /*
1226  * Avoid buffered writes when a open context credential's key would
1227  * expire soon.
1228  *
1229  * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
1230  *
1231  * Return 0 and set a credential flag which triggers the inode to flush
1232  * and performs  NFS_FILE_SYNC writes if the key will expired within
1233  * RPC_KEY_EXPIRE_TIMEO.
1234  */
1235 int
nfs_key_timeout_notify(struct file * filp,struct inode * inode)1236 nfs_key_timeout_notify(struct file *filp, struct inode *inode)
1237 {
1238 	struct nfs_open_context *ctx = nfs_file_open_context(filp);
1239 
1240 	if (nfs_ctx_key_to_expire(ctx, inode) &&
1241 	    !rcu_access_pointer(ctx->ll_cred))
1242 		/* Already expired! */
1243 		return -EACCES;
1244 	return 0;
1245 }
1246 
1247 /*
1248  * Test if the open context credential key is marked to expire soon.
1249  */
nfs_ctx_key_to_expire(struct nfs_open_context * ctx,struct inode * inode)1250 bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx, struct inode *inode)
1251 {
1252 	struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
1253 	struct rpc_cred *cred, *new, *old = NULL;
1254 	struct auth_cred acred = {
1255 		.cred = ctx->cred,
1256 	};
1257 	bool ret = false;
1258 
1259 	rcu_read_lock();
1260 	cred = rcu_dereference(ctx->ll_cred);
1261 	if (cred && !(cred->cr_ops->crkey_timeout &&
1262 		      cred->cr_ops->crkey_timeout(cred)))
1263 		goto out;
1264 	rcu_read_unlock();
1265 
1266 	new = auth->au_ops->lookup_cred(auth, &acred, 0);
1267 	if (new == cred) {
1268 		put_rpccred(new);
1269 		return true;
1270 	}
1271 	if (IS_ERR_OR_NULL(new)) {
1272 		new = NULL;
1273 		ret = true;
1274 	} else if (new->cr_ops->crkey_timeout &&
1275 		   new->cr_ops->crkey_timeout(new))
1276 		ret = true;
1277 
1278 	rcu_read_lock();
1279 	old = rcu_dereference_protected(xchg(&ctx->ll_cred,
1280 					     RCU_INITIALIZER(new)), 1);
1281 out:
1282 	rcu_read_unlock();
1283 	put_rpccred(old);
1284 	return ret;
1285 }
1286 
1287 /*
1288  * If the page cache is marked as unsafe or invalid, then we can't rely on
1289  * the PageUptodate() flag. In this case, we will need to turn off
1290  * write optimisations that depend on the page contents being correct.
1291  */
nfs_folio_write_uptodate(struct folio * folio,unsigned int pagelen)1292 static bool nfs_folio_write_uptodate(struct folio *folio, unsigned int pagelen)
1293 {
1294 	struct inode *inode = folio_file_mapping(folio)->host;
1295 	struct nfs_inode *nfsi = NFS_I(inode);
1296 
1297 	if (nfs_have_delegated_attributes(inode))
1298 		goto out;
1299 	if (nfsi->cache_validity &
1300 	    (NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_SIZE))
1301 		return false;
1302 	smp_rmb();
1303 	if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags) && pagelen != 0)
1304 		return false;
1305 out:
1306 	if (nfsi->cache_validity & NFS_INO_INVALID_DATA && pagelen != 0)
1307 		return false;
1308 	return folio_test_uptodate(folio) != 0;
1309 }
1310 
1311 static bool
is_whole_file_wrlock(struct file_lock * fl)1312 is_whole_file_wrlock(struct file_lock *fl)
1313 {
1314 	return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX &&
1315 			fl->fl_type == F_WRLCK;
1316 }
1317 
1318 /* If we know the page is up to date, and we're not using byte range locks (or
1319  * if we have the whole file locked for writing), it may be more efficient to
1320  * extend the write to cover the entire page in order to avoid fragmentation
1321  * inefficiencies.
1322  *
1323  * If the file is opened for synchronous writes then we can just skip the rest
1324  * of the checks.
1325  */
nfs_can_extend_write(struct file * file,struct folio * folio,unsigned int pagelen)1326 static int nfs_can_extend_write(struct file *file, struct folio *folio,
1327 				unsigned int pagelen)
1328 {
1329 	struct inode *inode = file_inode(file);
1330 	struct file_lock_context *flctx = locks_inode_context(inode);
1331 	struct file_lock *fl;
1332 	int ret;
1333 
1334 	if (file->f_flags & O_DSYNC)
1335 		return 0;
1336 	if (!nfs_folio_write_uptodate(folio, pagelen))
1337 		return 0;
1338 	if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
1339 		return 1;
1340 	if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
1341 		       list_empty_careful(&flctx->flc_posix)))
1342 		return 1;
1343 
1344 	/* Check to see if there are whole file write locks */
1345 	ret = 0;
1346 	spin_lock(&flctx->flc_lock);
1347 	if (!list_empty(&flctx->flc_posix)) {
1348 		fl = list_first_entry(&flctx->flc_posix, struct file_lock,
1349 					fl_list);
1350 		if (is_whole_file_wrlock(fl))
1351 			ret = 1;
1352 	} else if (!list_empty(&flctx->flc_flock)) {
1353 		fl = list_first_entry(&flctx->flc_flock, struct file_lock,
1354 					fl_list);
1355 		if (fl->fl_type == F_WRLCK)
1356 			ret = 1;
1357 	}
1358 	spin_unlock(&flctx->flc_lock);
1359 	return ret;
1360 }
1361 
1362 /*
1363  * Update and possibly write a cached page of an NFS file.
1364  *
1365  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
1366  * things with a page scheduled for an RPC call (e.g. invalidate it).
1367  */
nfs_update_folio(struct file * file,struct folio * folio,unsigned int offset,unsigned int count)1368 int nfs_update_folio(struct file *file, struct folio *folio,
1369 		     unsigned int offset, unsigned int count)
1370 {
1371 	struct nfs_open_context *ctx = nfs_file_open_context(file);
1372 	struct address_space *mapping = folio_file_mapping(folio);
1373 	struct inode *inode = mapping->host;
1374 	unsigned int pagelen = nfs_folio_length(folio);
1375 	int		status = 0;
1376 
1377 	nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
1378 
1379 	dprintk("NFS:       nfs_update_folio(%pD2 %d@%lld)\n", file, count,
1380 		(long long)(folio_file_pos(folio) + offset));
1381 
1382 	if (!count)
1383 		goto out;
1384 
1385 	if (nfs_can_extend_write(file, folio, pagelen)) {
1386 		count = max(count + offset, pagelen);
1387 		offset = 0;
1388 	}
1389 
1390 	status = nfs_writepage_setup(ctx, folio, offset, count);
1391 	if (status < 0)
1392 		nfs_set_pageerror(mapping);
1393 out:
1394 	dprintk("NFS:       nfs_update_folio returns %d (isize %lld)\n",
1395 			status, (long long)i_size_read(inode));
1396 	return status;
1397 }
1398 
flush_task_priority(int how)1399 static int flush_task_priority(int how)
1400 {
1401 	switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
1402 		case FLUSH_HIGHPRI:
1403 			return RPC_PRIORITY_HIGH;
1404 		case FLUSH_LOWPRI:
1405 			return RPC_PRIORITY_LOW;
1406 	}
1407 	return RPC_PRIORITY_NORMAL;
1408 }
1409 
nfs_initiate_write(struct nfs_pgio_header * hdr,struct rpc_message * msg,const struct nfs_rpc_ops * rpc_ops,struct rpc_task_setup * task_setup_data,int how)1410 static void nfs_initiate_write(struct nfs_pgio_header *hdr,
1411 			       struct rpc_message *msg,
1412 			       const struct nfs_rpc_ops *rpc_ops,
1413 			       struct rpc_task_setup *task_setup_data, int how)
1414 {
1415 	int priority = flush_task_priority(how);
1416 
1417 	if (IS_SWAPFILE(hdr->inode))
1418 		task_setup_data->flags |= RPC_TASK_SWAPPER;
1419 	task_setup_data->priority = priority;
1420 	rpc_ops->write_setup(hdr, msg, &task_setup_data->rpc_client);
1421 	trace_nfs_initiate_write(hdr);
1422 }
1423 
1424 /* If a nfs_flush_* function fails, it should remove reqs from @head and
1425  * call this on each, which will prepare them to be retried on next
1426  * writeback using standard nfs.
1427  */
nfs_redirty_request(struct nfs_page * req)1428 static void nfs_redirty_request(struct nfs_page *req)
1429 {
1430 	struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req));
1431 
1432 	/* Bump the transmission count */
1433 	req->wb_nio++;
1434 	nfs_mark_request_dirty(req);
1435 	atomic_long_inc(&nfsi->redirtied_pages);
1436 	nfs_page_end_writeback(req);
1437 	nfs_release_request(req);
1438 }
1439 
nfs_async_write_error(struct list_head * head,int error)1440 static void nfs_async_write_error(struct list_head *head, int error)
1441 {
1442 	struct nfs_page	*req;
1443 
1444 	while (!list_empty(head)) {
1445 		req = nfs_list_entry(head->next);
1446 		nfs_list_remove_request(req);
1447 		if (nfs_error_is_fatal_on_server(error))
1448 			nfs_write_error(req, error);
1449 		else
1450 			nfs_redirty_request(req);
1451 	}
1452 }
1453 
nfs_async_write_reschedule_io(struct nfs_pgio_header * hdr)1454 static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)
1455 {
1456 	nfs_async_write_error(&hdr->pages, 0);
1457 }
1458 
1459 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
1460 	.init_hdr = nfs_async_write_init,
1461 	.error_cleanup = nfs_async_write_error,
1462 	.completion = nfs_write_completion,
1463 	.reschedule_io = nfs_async_write_reschedule_io,
1464 };
1465 
nfs_pageio_init_write(struct nfs_pageio_descriptor * pgio,struct inode * inode,int ioflags,bool force_mds,const struct nfs_pgio_completion_ops * compl_ops)1466 void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1467 			       struct inode *inode, int ioflags, bool force_mds,
1468 			       const struct nfs_pgio_completion_ops *compl_ops)
1469 {
1470 	struct nfs_server *server = NFS_SERVER(inode);
1471 	const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
1472 
1473 #ifdef CONFIG_NFS_V4_1
1474 	if (server->pnfs_curr_ld && !force_mds)
1475 		pg_ops = server->pnfs_curr_ld->pg_write_ops;
1476 #endif
1477 	nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops,
1478 			server->wsize, ioflags);
1479 }
1480 EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
1481 
nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor * pgio)1482 void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1483 {
1484 	struct nfs_pgio_mirror *mirror;
1485 
1486 	if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
1487 		pgio->pg_ops->pg_cleanup(pgio);
1488 
1489 	pgio->pg_ops = &nfs_pgio_rw_ops;
1490 
1491 	nfs_pageio_stop_mirroring(pgio);
1492 
1493 	mirror = &pgio->pg_mirrors[0];
1494 	mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1495 }
1496 EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1497 
1498 
nfs_commit_prepare(struct rpc_task * task,void * calldata)1499 void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1500 {
1501 	struct nfs_commit_data *data = calldata;
1502 
1503 	NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1504 }
1505 
nfs_writeback_check_extend(struct nfs_pgio_header * hdr,struct nfs_fattr * fattr)1506 static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
1507 		struct nfs_fattr *fattr)
1508 {
1509 	struct nfs_pgio_args *argp = &hdr->args;
1510 	struct nfs_pgio_res *resp = &hdr->res;
1511 	u64 size = argp->offset + resp->count;
1512 
1513 	if (!(fattr->valid & NFS_ATTR_FATTR_SIZE))
1514 		fattr->size = size;
1515 	if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) {
1516 		fattr->valid &= ~NFS_ATTR_FATTR_SIZE;
1517 		return;
1518 	}
1519 	if (size != fattr->size)
1520 		return;
1521 	/* Set attribute barrier */
1522 	nfs_fattr_set_barrier(fattr);
1523 	/* ...and update size */
1524 	fattr->valid |= NFS_ATTR_FATTR_SIZE;
1525 }
1526 
nfs_writeback_update_inode(struct nfs_pgio_header * hdr)1527 void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
1528 {
1529 	struct nfs_fattr *fattr = &hdr->fattr;
1530 	struct inode *inode = hdr->inode;
1531 
1532 	spin_lock(&inode->i_lock);
1533 	nfs_writeback_check_extend(hdr, fattr);
1534 	nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
1535 	spin_unlock(&inode->i_lock);
1536 }
1537 EXPORT_SYMBOL_GPL(nfs_writeback_update_inode);
1538 
1539 /*
1540  * This function is called when the WRITE call is complete.
1541  */
nfs_writeback_done(struct rpc_task * task,struct nfs_pgio_header * hdr,struct inode * inode)1542 static int nfs_writeback_done(struct rpc_task *task,
1543 			      struct nfs_pgio_header *hdr,
1544 			      struct inode *inode)
1545 {
1546 	int status;
1547 
1548 	/*
1549 	 * ->write_done will attempt to use post-op attributes to detect
1550 	 * conflicting writes by other clients.  A strict interpretation
1551 	 * of close-to-open would allow us to continue caching even if
1552 	 * another writer had changed the file, but some applications
1553 	 * depend on tighter cache coherency when writing.
1554 	 */
1555 	status = NFS_PROTO(inode)->write_done(task, hdr);
1556 	if (status != 0)
1557 		return status;
1558 
1559 	nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count);
1560 	trace_nfs_writeback_done(task, hdr);
1561 
1562 	if (task->tk_status >= 0) {
1563 		enum nfs3_stable_how committed = hdr->res.verf->committed;
1564 
1565 		if (committed == NFS_UNSTABLE) {
1566 			/*
1567 			 * We have some uncommitted data on the server at
1568 			 * this point, so ensure that we keep track of that
1569 			 * fact irrespective of what later writes do.
1570 			 */
1571 			set_bit(NFS_IOHDR_UNSTABLE_WRITES, &hdr->flags);
1572 		}
1573 
1574 		if (committed < hdr->args.stable) {
1575 			/* We tried a write call, but the server did not
1576 			 * commit data to stable storage even though we
1577 			 * requested it.
1578 			 * Note: There is a known bug in Tru64 < 5.0 in which
1579 			 *	 the server reports NFS_DATA_SYNC, but performs
1580 			 *	 NFS_FILE_SYNC. We therefore implement this checking
1581 			 *	 as a dprintk() in order to avoid filling syslog.
1582 			 */
1583 			static unsigned long    complain;
1584 
1585 			/* Note this will print the MDS for a DS write */
1586 			if (time_before(complain, jiffies)) {
1587 				dprintk("NFS:       faulty NFS server %s:"
1588 					" (committed = %d) != (stable = %d)\n",
1589 					NFS_SERVER(inode)->nfs_client->cl_hostname,
1590 					committed, hdr->args.stable);
1591 				complain = jiffies + 300 * HZ;
1592 			}
1593 		}
1594 	}
1595 
1596 	/* Deal with the suid/sgid bit corner case */
1597 	if (nfs_should_remove_suid(inode)) {
1598 		spin_lock(&inode->i_lock);
1599 		nfs_set_cache_invalid(inode, NFS_INO_INVALID_MODE);
1600 		spin_unlock(&inode->i_lock);
1601 	}
1602 	return 0;
1603 }
1604 
1605 /*
1606  * This function is called when the WRITE call is complete.
1607  */
nfs_writeback_result(struct rpc_task * task,struct nfs_pgio_header * hdr)1608 static void nfs_writeback_result(struct rpc_task *task,
1609 				 struct nfs_pgio_header *hdr)
1610 {
1611 	struct nfs_pgio_args	*argp = &hdr->args;
1612 	struct nfs_pgio_res	*resp = &hdr->res;
1613 
1614 	if (resp->count < argp->count) {
1615 		static unsigned long    complain;
1616 
1617 		/* This a short write! */
1618 		nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE);
1619 
1620 		/* Has the server at least made some progress? */
1621 		if (resp->count == 0) {
1622 			if (time_before(complain, jiffies)) {
1623 				printk(KERN_WARNING
1624 				       "NFS: Server wrote zero bytes, expected %u.\n",
1625 				       argp->count);
1626 				complain = jiffies + 300 * HZ;
1627 			}
1628 			nfs_set_pgio_error(hdr, -EIO, argp->offset);
1629 			task->tk_status = -EIO;
1630 			return;
1631 		}
1632 
1633 		/* For non rpc-based layout drivers, retry-through-MDS */
1634 		if (!task->tk_ops) {
1635 			hdr->pnfs_error = -EAGAIN;
1636 			return;
1637 		}
1638 
1639 		/* Was this an NFSv2 write or an NFSv3 stable write? */
1640 		if (resp->verf->committed != NFS_UNSTABLE) {
1641 			/* Resend from where the server left off */
1642 			hdr->mds_offset += resp->count;
1643 			argp->offset += resp->count;
1644 			argp->pgbase += resp->count;
1645 			argp->count -= resp->count;
1646 		} else {
1647 			/* Resend as a stable write in order to avoid
1648 			 * headaches in the case of a server crash.
1649 			 */
1650 			argp->stable = NFS_FILE_SYNC;
1651 		}
1652 		resp->count = 0;
1653 		resp->verf->committed = 0;
1654 		rpc_restart_call_prepare(task);
1655 	}
1656 }
1657 
wait_on_commit(struct nfs_mds_commit_info * cinfo)1658 static int wait_on_commit(struct nfs_mds_commit_info *cinfo)
1659 {
1660 	return wait_var_event_killable(&cinfo->rpcs_out,
1661 				       !atomic_read(&cinfo->rpcs_out));
1662 }
1663 
nfs_commit_begin(struct nfs_mds_commit_info * cinfo)1664 static void nfs_commit_begin(struct nfs_mds_commit_info *cinfo)
1665 {
1666 	atomic_inc(&cinfo->rpcs_out);
1667 }
1668 
nfs_commit_end(struct nfs_mds_commit_info * cinfo)1669 bool nfs_commit_end(struct nfs_mds_commit_info *cinfo)
1670 {
1671 	if (atomic_dec_and_test(&cinfo->rpcs_out)) {
1672 		wake_up_var(&cinfo->rpcs_out);
1673 		return true;
1674 	}
1675 	return false;
1676 }
1677 
nfs_commitdata_release(struct nfs_commit_data * data)1678 void nfs_commitdata_release(struct nfs_commit_data *data)
1679 {
1680 	put_nfs_open_context(data->context);
1681 	nfs_commit_free(data);
1682 }
1683 EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1684 
nfs_initiate_commit(struct rpc_clnt * clnt,struct nfs_commit_data * data,const struct nfs_rpc_ops * nfs_ops,const struct rpc_call_ops * call_ops,int how,int flags)1685 int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
1686 			const struct nfs_rpc_ops *nfs_ops,
1687 			const struct rpc_call_ops *call_ops,
1688 			int how, int flags)
1689 {
1690 	struct rpc_task *task;
1691 	int priority = flush_task_priority(how);
1692 	struct rpc_message msg = {
1693 		.rpc_argp = &data->args,
1694 		.rpc_resp = &data->res,
1695 		.rpc_cred = data->cred,
1696 	};
1697 	struct rpc_task_setup task_setup_data = {
1698 		.task = &data->task,
1699 		.rpc_client = clnt,
1700 		.rpc_message = &msg,
1701 		.callback_ops = call_ops,
1702 		.callback_data = data,
1703 		.workqueue = nfsiod_workqueue,
1704 		.flags = RPC_TASK_ASYNC | flags,
1705 		.priority = priority,
1706 	};
1707 
1708 	if (nfs_server_capable(data->inode, NFS_CAP_MOVEABLE))
1709 		task_setup_data.flags |= RPC_TASK_MOVEABLE;
1710 
1711 	/* Set up the initial task struct.  */
1712 	nfs_ops->commit_setup(data, &msg, &task_setup_data.rpc_client);
1713 	trace_nfs_initiate_commit(data);
1714 
1715 	dprintk("NFS: initiated commit call\n");
1716 
1717 	task = rpc_run_task(&task_setup_data);
1718 	if (IS_ERR(task))
1719 		return PTR_ERR(task);
1720 	if (how & FLUSH_SYNC)
1721 		rpc_wait_for_completion_task(task);
1722 	rpc_put_task(task);
1723 	return 0;
1724 }
1725 EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1726 
nfs_get_lwb(struct list_head * head)1727 static loff_t nfs_get_lwb(struct list_head *head)
1728 {
1729 	loff_t lwb = 0;
1730 	struct nfs_page *req;
1731 
1732 	list_for_each_entry(req, head, wb_list)
1733 		if (lwb < (req_offset(req) + req->wb_bytes))
1734 			lwb = req_offset(req) + req->wb_bytes;
1735 
1736 	return lwb;
1737 }
1738 
1739 /*
1740  * Set up the argument/result storage required for the RPC call.
1741  */
nfs_init_commit(struct nfs_commit_data * data,struct list_head * head,struct pnfs_layout_segment * lseg,struct nfs_commit_info * cinfo)1742 void nfs_init_commit(struct nfs_commit_data *data,
1743 		     struct list_head *head,
1744 		     struct pnfs_layout_segment *lseg,
1745 		     struct nfs_commit_info *cinfo)
1746 {
1747 	struct nfs_page *first;
1748 	struct nfs_open_context *ctx;
1749 	struct inode *inode;
1750 
1751 	/* Set up the RPC argument and reply structs
1752 	 * NB: take care not to mess about with data->commit et al. */
1753 
1754 	if (head)
1755 		list_splice_init(head, &data->pages);
1756 
1757 	first = nfs_list_entry(data->pages.next);
1758 	ctx = nfs_req_openctx(first);
1759 	inode = d_inode(ctx->dentry);
1760 
1761 	data->inode	  = inode;
1762 	data->cred	  = ctx->cred;
1763 	data->lseg	  = lseg; /* reference transferred */
1764 	/* only set lwb for pnfs commit */
1765 	if (lseg)
1766 		data->lwb = nfs_get_lwb(&data->pages);
1767 	data->mds_ops     = &nfs_commit_ops;
1768 	data->completion_ops = cinfo->completion_ops;
1769 	data->dreq	  = cinfo->dreq;
1770 
1771 	data->args.fh     = NFS_FH(data->inode);
1772 	/* Note: we always request a commit of the entire inode */
1773 	data->args.offset = 0;
1774 	data->args.count  = 0;
1775 	data->context     = get_nfs_open_context(ctx);
1776 	data->res.fattr   = &data->fattr;
1777 	data->res.verf    = &data->verf;
1778 	nfs_fattr_init(&data->fattr);
1779 	nfs_commit_begin(cinfo->mds);
1780 }
1781 EXPORT_SYMBOL_GPL(nfs_init_commit);
1782 
nfs_retry_commit(struct list_head * page_list,struct pnfs_layout_segment * lseg,struct nfs_commit_info * cinfo,u32 ds_commit_idx)1783 void nfs_retry_commit(struct list_head *page_list,
1784 		      struct pnfs_layout_segment *lseg,
1785 		      struct nfs_commit_info *cinfo,
1786 		      u32 ds_commit_idx)
1787 {
1788 	struct nfs_page *req;
1789 
1790 	while (!list_empty(page_list)) {
1791 		req = nfs_list_entry(page_list->next);
1792 		nfs_list_remove_request(req);
1793 		nfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx);
1794 		nfs_folio_clear_commit(nfs_page_to_folio(req));
1795 		nfs_unlock_and_release_request(req);
1796 	}
1797 }
1798 EXPORT_SYMBOL_GPL(nfs_retry_commit);
1799 
nfs_commit_resched_write(struct nfs_commit_info * cinfo,struct nfs_page * req)1800 static void nfs_commit_resched_write(struct nfs_commit_info *cinfo,
1801 				     struct nfs_page *req)
1802 {
1803 	struct folio *folio = nfs_page_to_folio(req);
1804 
1805 	filemap_dirty_folio(folio_mapping(folio), folio);
1806 }
1807 
1808 /*
1809  * Commit dirty pages
1810  */
1811 static int
nfs_commit_list(struct inode * inode,struct list_head * head,int how,struct nfs_commit_info * cinfo)1812 nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1813 		struct nfs_commit_info *cinfo)
1814 {
1815 	struct nfs_commit_data	*data;
1816 	unsigned short task_flags = 0;
1817 
1818 	/* another commit raced with us */
1819 	if (list_empty(head))
1820 		return 0;
1821 
1822 	data = nfs_commitdata_alloc();
1823 	if (!data) {
1824 		nfs_retry_commit(head, NULL, cinfo, -1);
1825 		return -ENOMEM;
1826 	}
1827 
1828 	/* Set up the argument struct */
1829 	nfs_init_commit(data, head, NULL, cinfo);
1830 	if (NFS_SERVER(inode)->nfs_client->cl_minorversion)
1831 		task_flags = RPC_TASK_MOVEABLE;
1832 	return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode),
1833 				   data->mds_ops, how,
1834 				   RPC_TASK_CRED_NOREF | task_flags);
1835 }
1836 
1837 /*
1838  * COMMIT call returned
1839  */
nfs_commit_done(struct rpc_task * task,void * calldata)1840 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1841 {
1842 	struct nfs_commit_data	*data = calldata;
1843 
1844 	/* Call the NFS version-specific code */
1845 	NFS_PROTO(data->inode)->commit_done(task, data);
1846 	trace_nfs_commit_done(task, data);
1847 }
1848 
nfs_commit_release_pages(struct nfs_commit_data * data)1849 static void nfs_commit_release_pages(struct nfs_commit_data *data)
1850 {
1851 	const struct nfs_writeverf *verf = data->res.verf;
1852 	struct nfs_page	*req;
1853 	int status = data->task.tk_status;
1854 	struct nfs_commit_info cinfo;
1855 	struct nfs_server *nfss;
1856 	struct folio *folio;
1857 
1858 	while (!list_empty(&data->pages)) {
1859 		req = nfs_list_entry(data->pages.next);
1860 		nfs_list_remove_request(req);
1861 		folio = nfs_page_to_folio(req);
1862 		nfs_folio_clear_commit(folio);
1863 
1864 		dprintk("NFS:       commit (%s/%llu %d@%lld)",
1865 			nfs_req_openctx(req)->dentry->d_sb->s_id,
1866 			(unsigned long long)NFS_FILEID(d_inode(nfs_req_openctx(req)->dentry)),
1867 			req->wb_bytes,
1868 			(long long)req_offset(req));
1869 		if (status < 0) {
1870 			if (folio) {
1871 				trace_nfs_commit_error(data->inode, req,
1872 						       status);
1873 				nfs_mapping_set_error(folio, status);
1874 				nfs_inode_remove_request(req);
1875 			}
1876 			dprintk_cont(", error = %d\n", status);
1877 			goto next;
1878 		}
1879 
1880 		/* Okay, COMMIT succeeded, apparently. Check the verifier
1881 		 * returned by the server against all stored verfs. */
1882 		if (nfs_write_match_verf(verf, req)) {
1883 			/* We have a match */
1884 			if (folio)
1885 				nfs_inode_remove_request(req);
1886 			dprintk_cont(" OK\n");
1887 			goto next;
1888 		}
1889 		/* We have a mismatch. Write the page again */
1890 		dprintk_cont(" mismatch\n");
1891 		nfs_mark_request_dirty(req);
1892 		atomic_long_inc(&NFS_I(data->inode)->redirtied_pages);
1893 	next:
1894 		nfs_unlock_and_release_request(req);
1895 		/* Latency breaker */
1896 		cond_resched();
1897 	}
1898 	nfss = NFS_SERVER(data->inode);
1899 	if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
1900 		nfss->write_congested = 0;
1901 
1902 	nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1903 	nfs_commit_end(cinfo.mds);
1904 }
1905 
nfs_commit_release(void * calldata)1906 static void nfs_commit_release(void *calldata)
1907 {
1908 	struct nfs_commit_data *data = calldata;
1909 
1910 	data->completion_ops->completion(data);
1911 	nfs_commitdata_release(calldata);
1912 }
1913 
1914 static const struct rpc_call_ops nfs_commit_ops = {
1915 	.rpc_call_prepare = nfs_commit_prepare,
1916 	.rpc_call_done = nfs_commit_done,
1917 	.rpc_release = nfs_commit_release,
1918 };
1919 
1920 static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1921 	.completion = nfs_commit_release_pages,
1922 	.resched_write = nfs_commit_resched_write,
1923 };
1924 
nfs_generic_commit_list(struct inode * inode,struct list_head * head,int how,struct nfs_commit_info * cinfo)1925 int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1926 			    int how, struct nfs_commit_info *cinfo)
1927 {
1928 	int status;
1929 
1930 	status = pnfs_commit_list(inode, head, how, cinfo);
1931 	if (status == PNFS_NOT_ATTEMPTED)
1932 		status = nfs_commit_list(inode, head, how, cinfo);
1933 	return status;
1934 }
1935 
__nfs_commit_inode(struct inode * inode,int how,struct writeback_control * wbc)1936 static int __nfs_commit_inode(struct inode *inode, int how,
1937 		struct writeback_control *wbc)
1938 {
1939 	LIST_HEAD(head);
1940 	struct nfs_commit_info cinfo;
1941 	int may_wait = how & FLUSH_SYNC;
1942 	int ret, nscan;
1943 
1944 	how &= ~FLUSH_SYNC;
1945 	nfs_init_cinfo_from_inode(&cinfo, inode);
1946 	nfs_commit_begin(cinfo.mds);
1947 	for (;;) {
1948 		ret = nscan = nfs_scan_commit(inode, &head, &cinfo);
1949 		if (ret <= 0)
1950 			break;
1951 		ret = nfs_generic_commit_list(inode, &head, how, &cinfo);
1952 		if (ret < 0)
1953 			break;
1954 		ret = 0;
1955 		if (wbc && wbc->sync_mode == WB_SYNC_NONE) {
1956 			if (nscan < wbc->nr_to_write)
1957 				wbc->nr_to_write -= nscan;
1958 			else
1959 				wbc->nr_to_write = 0;
1960 		}
1961 		if (nscan < INT_MAX)
1962 			break;
1963 		cond_resched();
1964 	}
1965 	nfs_commit_end(cinfo.mds);
1966 	if (ret || !may_wait)
1967 		return ret;
1968 	return wait_on_commit(cinfo.mds);
1969 }
1970 
nfs_commit_inode(struct inode * inode,int how)1971 int nfs_commit_inode(struct inode *inode, int how)
1972 {
1973 	return __nfs_commit_inode(inode, how, NULL);
1974 }
1975 EXPORT_SYMBOL_GPL(nfs_commit_inode);
1976 
nfs_write_inode(struct inode * inode,struct writeback_control * wbc)1977 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1978 {
1979 	struct nfs_inode *nfsi = NFS_I(inode);
1980 	int flags = FLUSH_SYNC;
1981 	int ret = 0;
1982 
1983 	if (wbc->sync_mode == WB_SYNC_NONE) {
1984 		/* no commits means nothing needs to be done */
1985 		if (!atomic_long_read(&nfsi->commit_info.ncommit))
1986 			goto check_requests_outstanding;
1987 
1988 		/* Don't commit yet if this is a non-blocking flush and there
1989 		 * are a lot of outstanding writes for this mapping.
1990 		 */
1991 		if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))
1992 			goto out_mark_dirty;
1993 
1994 		/* don't wait for the COMMIT response */
1995 		flags = 0;
1996 	}
1997 
1998 	ret = __nfs_commit_inode(inode, flags, wbc);
1999 	if (!ret) {
2000 		if (flags & FLUSH_SYNC)
2001 			return 0;
2002 	} else if (atomic_long_read(&nfsi->commit_info.ncommit))
2003 		goto out_mark_dirty;
2004 
2005 check_requests_outstanding:
2006 	if (!atomic_read(&nfsi->commit_info.rpcs_out))
2007 		return ret;
2008 out_mark_dirty:
2009 	__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
2010 	return ret;
2011 }
2012 EXPORT_SYMBOL_GPL(nfs_write_inode);
2013 
2014 /*
2015  * Wrapper for filemap_write_and_wait_range()
2016  *
2017  * Needed for pNFS in order to ensure data becomes visible to the
2018  * client.
2019  */
nfs_filemap_write_and_wait_range(struct address_space * mapping,loff_t lstart,loff_t lend)2020 int nfs_filemap_write_and_wait_range(struct address_space *mapping,
2021 		loff_t lstart, loff_t lend)
2022 {
2023 	int ret;
2024 
2025 	ret = filemap_write_and_wait_range(mapping, lstart, lend);
2026 	if (ret == 0)
2027 		ret = pnfs_sync_inode(mapping->host, true);
2028 	return ret;
2029 }
2030 EXPORT_SYMBOL_GPL(nfs_filemap_write_and_wait_range);
2031 
2032 /*
2033  * flush the inode to disk.
2034  */
nfs_wb_all(struct inode * inode)2035 int nfs_wb_all(struct inode *inode)
2036 {
2037 	int ret;
2038 
2039 	trace_nfs_writeback_inode_enter(inode);
2040 
2041 	ret = filemap_write_and_wait(inode->i_mapping);
2042 	if (ret)
2043 		goto out;
2044 	ret = nfs_commit_inode(inode, FLUSH_SYNC);
2045 	if (ret < 0)
2046 		goto out;
2047 	pnfs_sync_inode(inode, true);
2048 	ret = 0;
2049 
2050 out:
2051 	trace_nfs_writeback_inode_exit(inode, ret);
2052 	return ret;
2053 }
2054 EXPORT_SYMBOL_GPL(nfs_wb_all);
2055 
nfs_wb_folio_cancel(struct inode * inode,struct folio * folio)2056 int nfs_wb_folio_cancel(struct inode *inode, struct folio *folio)
2057 {
2058 	struct nfs_page *req;
2059 	int ret = 0;
2060 
2061 	folio_wait_writeback(folio);
2062 
2063 	/* blocking call to cancel all requests and join to a single (head)
2064 	 * request */
2065 	req = nfs_lock_and_join_requests(folio);
2066 
2067 	if (IS_ERR(req)) {
2068 		ret = PTR_ERR(req);
2069 	} else if (req) {
2070 		/* all requests from this folio have been cancelled by
2071 		 * nfs_lock_and_join_requests, so just remove the head
2072 		 * request from the inode / page_private pointer and
2073 		 * release it */
2074 		nfs_inode_remove_request(req);
2075 		nfs_unlock_and_release_request(req);
2076 	}
2077 
2078 	return ret;
2079 }
2080 
2081 /**
2082  * nfs_wb_folio - Write back all requests on one page
2083  * @inode: pointer to page
2084  * @folio: pointer to folio
2085  *
2086  * Assumes that the folio has been locked by the caller, and will
2087  * not unlock it.
2088  */
nfs_wb_folio(struct inode * inode,struct folio * folio)2089 int nfs_wb_folio(struct inode *inode, struct folio *folio)
2090 {
2091 	loff_t range_start = folio_file_pos(folio);
2092 	loff_t range_end = range_start + (loff_t)folio_size(folio) - 1;
2093 	struct writeback_control wbc = {
2094 		.sync_mode = WB_SYNC_ALL,
2095 		.nr_to_write = 0,
2096 		.range_start = range_start,
2097 		.range_end = range_end,
2098 	};
2099 	int ret;
2100 
2101 	trace_nfs_writeback_folio(inode, folio);
2102 
2103 	for (;;) {
2104 		folio_wait_writeback(folio);
2105 		if (folio_clear_dirty_for_io(folio)) {
2106 			ret = nfs_writepage_locked(folio, &wbc);
2107 			if (ret < 0)
2108 				goto out_error;
2109 			continue;
2110 		}
2111 		ret = 0;
2112 		if (!folio_test_private(folio))
2113 			break;
2114 		ret = nfs_commit_inode(inode, FLUSH_SYNC);
2115 		if (ret < 0)
2116 			goto out_error;
2117 	}
2118 out_error:
2119 	trace_nfs_writeback_folio_done(inode, folio, ret);
2120 	return ret;
2121 }
2122 
2123 #ifdef CONFIG_MIGRATION
nfs_migrate_folio(struct address_space * mapping,struct folio * dst,struct folio * src,enum migrate_mode mode)2124 int nfs_migrate_folio(struct address_space *mapping, struct folio *dst,
2125 		struct folio *src, enum migrate_mode mode)
2126 {
2127 	/*
2128 	 * If the private flag is set, the folio is currently associated with
2129 	 * an in-progress read or write request. Don't try to migrate it.
2130 	 *
2131 	 * FIXME: we could do this in principle, but we'll need a way to ensure
2132 	 *        that we can safely release the inode reference while holding
2133 	 *        the folio lock.
2134 	 */
2135 	if (folio_test_private(src))
2136 		return -EBUSY;
2137 
2138 	if (folio_test_fscache(src)) {
2139 		if (mode == MIGRATE_ASYNC)
2140 			return -EBUSY;
2141 		folio_wait_fscache(src);
2142 	}
2143 
2144 	return migrate_folio(mapping, dst, src, mode);
2145 }
2146 #endif
2147 
nfs_init_writepagecache(void)2148 int __init nfs_init_writepagecache(void)
2149 {
2150 	nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
2151 					     sizeof(struct nfs_pgio_header),
2152 					     0, SLAB_HWCACHE_ALIGN,
2153 					     NULL);
2154 	if (nfs_wdata_cachep == NULL)
2155 		return -ENOMEM;
2156 
2157 	nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
2158 						     nfs_wdata_cachep);
2159 	if (nfs_wdata_mempool == NULL)
2160 		goto out_destroy_write_cache;
2161 
2162 	nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
2163 					     sizeof(struct nfs_commit_data),
2164 					     0, SLAB_HWCACHE_ALIGN,
2165 					     NULL);
2166 	if (nfs_cdata_cachep == NULL)
2167 		goto out_destroy_write_mempool;
2168 
2169 	nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
2170 						      nfs_cdata_cachep);
2171 	if (nfs_commit_mempool == NULL)
2172 		goto out_destroy_commit_cache;
2173 
2174 	/*
2175 	 * NFS congestion size, scale with available memory.
2176 	 *
2177 	 *  64MB:    8192k
2178 	 * 128MB:   11585k
2179 	 * 256MB:   16384k
2180 	 * 512MB:   23170k
2181 	 *   1GB:   32768k
2182 	 *   2GB:   46340k
2183 	 *   4GB:   65536k
2184 	 *   8GB:   92681k
2185 	 *  16GB:  131072k
2186 	 *
2187 	 * This allows larger machines to have larger/more transfers.
2188 	 * Limit the default to 256M
2189 	 */
2190 	nfs_congestion_kb = (16*int_sqrt(totalram_pages())) << (PAGE_SHIFT-10);
2191 	if (nfs_congestion_kb > 256*1024)
2192 		nfs_congestion_kb = 256*1024;
2193 
2194 	return 0;
2195 
2196 out_destroy_commit_cache:
2197 	kmem_cache_destroy(nfs_cdata_cachep);
2198 out_destroy_write_mempool:
2199 	mempool_destroy(nfs_wdata_mempool);
2200 out_destroy_write_cache:
2201 	kmem_cache_destroy(nfs_wdata_cachep);
2202 	return -ENOMEM;
2203 }
2204 
nfs_destroy_writepagecache(void)2205 void nfs_destroy_writepagecache(void)
2206 {
2207 	mempool_destroy(nfs_commit_mempool);
2208 	kmem_cache_destroy(nfs_cdata_cachep);
2209 	mempool_destroy(nfs_wdata_mempool);
2210 	kmem_cache_destroy(nfs_wdata_cachep);
2211 }
2212 
2213 static const struct nfs_rw_ops nfs_rw_write_ops = {
2214 	.rw_alloc_header	= nfs_writehdr_alloc,
2215 	.rw_free_header		= nfs_writehdr_free,
2216 	.rw_done		= nfs_writeback_done,
2217 	.rw_result		= nfs_writeback_result,
2218 	.rw_initiate		= nfs_initiate_write,
2219 };
2220