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
  47struct nfs_io_completion {
  48	void (*complete)(void *data);
  49	void *data;
  50	struct kref refcount;
  51};
  52
  53/*
  54 * Local function declarations
  55 */
  56static void nfs_redirty_request(struct nfs_page *req);
  57static const struct rpc_call_ops nfs_commit_ops;
  58static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
  59static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
  60static const struct nfs_rw_ops nfs_rw_write_ops;
  61static void nfs_inode_remove_request(struct nfs_page *req);
  62static void nfs_clear_request_commit(struct nfs_commit_info *cinfo,
  63				     struct nfs_page *req);
  64static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
  65				      struct inode *inode);
  66static struct nfs_page *
  67nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
  68						struct folio *folio);
  69
  70static struct kmem_cache *nfs_wdata_cachep;
  71static mempool_t *nfs_wdata_mempool;
  72static struct kmem_cache *nfs_cdata_cachep;
  73static mempool_t *nfs_commit_mempool;
  74
  75struct 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}
  89EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
  90
  91void nfs_commit_free(struct nfs_commit_data *p)
  92{
  93	mempool_free(p, nfs_commit_mempool);
  94}
  95EXPORT_SYMBOL_GPL(nfs_commit_free);
  96
  97static 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
 112static void nfs_writehdr_free(struct nfs_pgio_header *hdr)
 113{
 114	mempool_free(hdr, nfs_wdata_mempool);
 115}
 116
 117static 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
 122static 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
 130static 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
 138static void nfs_io_completion_get(struct nfs_io_completion *ioc)
 139{
 140	if (ioc != NULL)
 141		kref_get(&ioc->refcount);
 142}
 143
 144static 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
 150static void
 151nfs_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
 159static int
 160nfs_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
 175static 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 */
 188static 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->i_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->i_private_lock);
 202	return req;
 203}
 204
 205static 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 */
 231static 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
 241static 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 */
 272static 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);
 291out:
 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 */
 297static 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
 310static 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 */
 335static struct nfs_page *
 336nfs_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 */
 359static 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 */
 381static 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
 392static 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
 405int 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
 411static 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
 420static 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
 430static 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 */
 449static void
 450nfs_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 */
 506void 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 */
 566static 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
 595static 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 */
 608static 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);
 646out:
 647	return ret;
 648out_launder:
 649	nfs_write_error(req, ret);
 650	return 0;
 651}
 652
 653static 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 */
 663static 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		return AOP_WRITEPAGE_ACTIVATE;
 673
 674	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 675	nfs_pageio_init_write(&pgio, inode, 0, false,
 676			      &nfs_async_write_completion_ops);
 677	err = nfs_do_writepage(folio, wbc, &pgio);
 678	pgio.pg_error = 0;
 679	nfs_pageio_complete(&pgio);
 680	return err;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 681}
 682
 683static int nfs_writepages_callback(struct folio *folio,
 684				   struct writeback_control *wbc, void *data)
 685{
 686	int ret;
 687
 688	ret = nfs_do_writepage(folio, wbc, data);
 689	if (ret != AOP_WRITEPAGE_ACTIVATE)
 690		folio_unlock(folio);
 691	return ret;
 692}
 693
 694static void nfs_io_completion_commit(void *inode)
 695{
 696	nfs_commit_inode(inode, 0);
 697}
 698
 699int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 700{
 701	struct inode *inode = mapping->host;
 702	struct nfs_pageio_descriptor pgio;
 703	struct nfs_io_completion *ioc = NULL;
 704	unsigned int mntflags = NFS_SERVER(inode)->flags;
 705	int priority = 0;
 706	int err;
 707
 708	if (wbc->sync_mode == WB_SYNC_NONE &&
 709	    NFS_SERVER(inode)->write_congested)
 710		return 0;
 711
 712	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 713
 714	if (!(mntflags & NFS_MOUNT_WRITE_EAGER) || wbc->for_kupdate ||
 715	    wbc->for_background || wbc->for_sync || wbc->for_reclaim) {
 716		ioc = nfs_io_completion_alloc(GFP_KERNEL);
 717		if (ioc)
 718			nfs_io_completion_init(ioc, nfs_io_completion_commit,
 719					       inode);
 720		priority = wb_priority(wbc);
 721	}
 722
 723	do {
 724		nfs_pageio_init_write(&pgio, inode, priority, false,
 725				      &nfs_async_write_completion_ops);
 726		pgio.pg_io_completion = ioc;
 727		err = write_cache_pages(mapping, wbc, nfs_writepages_callback,
 728					&pgio);
 729		pgio.pg_error = 0;
 730		nfs_pageio_complete(&pgio);
 731		if (err == -EAGAIN && mntflags & NFS_MOUNT_SOFTERR)
 732			break;
 733	} while (err < 0 && !nfs_error_is_fatal(err));
 734	nfs_io_completion_put(ioc);
 735
 736	if (err < 0)
 737		goto out_err;
 
 
 
 738	return 0;
 739out_err:
 740	return err;
 741}
 742
 743/*
 744 * Insert a write request into an inode
 745 */
 746static void nfs_inode_add_request(struct nfs_page *req)
 747{
 748	struct folio *folio = nfs_page_to_folio(req);
 749	struct address_space *mapping = folio_file_mapping(folio);
 750	struct nfs_inode *nfsi = NFS_I(mapping->host);
 751
 752	WARN_ON_ONCE(req->wb_this_page != req);
 753
 754	/* Lock the request! */
 755	nfs_lock_request(req);
 756
 757	/*
 758	 * Swap-space should not get truncated. Hence no need to plug the race
 759	 * with invalidate/truncate.
 760	 */
 761	spin_lock(&mapping->i_private_lock);
 762	if (likely(!folio_test_swapcache(folio))) {
 
 
 
 763		set_bit(PG_MAPPED, &req->wb_flags);
 764		folio_set_private(folio);
 765		folio->private = req;
 766	}
 767	spin_unlock(&mapping->i_private_lock);
 768	atomic_long_inc(&nfsi->nrequests);
 769	/* this a head request for a page group - mark it as having an
 770	 * extra reference so sub groups can follow suit.
 771	 * This flag also informs pgio layer when to bump nrequests when
 772	 * adding subrequests. */
 773	WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
 774	kref_get(&req->wb_kref);
 775}
 776
 777/*
 778 * Remove a write request from an inode
 779 */
 780static void nfs_inode_remove_request(struct nfs_page *req)
 781{
 782	struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req));
 
 
 
 783
 784	if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
 785		struct folio *folio = nfs_page_to_folio(req->wb_head);
 786		struct address_space *mapping = folio_file_mapping(folio);
 787
 788		spin_lock(&mapping->i_private_lock);
 789		if (likely(folio && !folio_test_swapcache(folio))) {
 790			folio->private = NULL;
 791			folio_clear_private(folio);
 792			clear_bit(PG_MAPPED, &req->wb_head->wb_flags);
 793		}
 794		spin_unlock(&mapping->i_private_lock);
 795	}
 796
 797	if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) {
 798		atomic_long_dec(&nfsi->nrequests);
 799		nfs_release_request(req);
 
 800	}
 801}
 802
 803static void nfs_mark_request_dirty(struct nfs_page *req)
 
 804{
 805	struct folio *folio = nfs_page_to_folio(req);
 806	if (folio)
 807		filemap_dirty_folio(folio_mapping(folio), folio);
 808}
 809
 810/*
 811 * nfs_page_search_commits_for_head_request_locked
 812 *
 813 * Search through commit lists on @inode for the head request for @folio.
 814 * Must be called while holding the inode (which is cinfo) lock.
 815 *
 816 * Returns the head request if found, or NULL if not found.
 817 */
 818static struct nfs_page *
 819nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
 820						struct folio *folio)
 821{
 822	struct nfs_page *freq, *t;
 823	struct nfs_commit_info cinfo;
 824	struct inode *inode = &nfsi->vfs_inode;
 825
 826	nfs_init_cinfo_from_inode(&cinfo, inode);
 827
 828	/* search through pnfs commit lists */
 829	freq = pnfs_search_commit_reqs(inode, &cinfo, folio);
 830	if (freq)
 831		return freq->wb_head;
 832
 833	/* Linearly search the commit list for the correct request */
 834	list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) {
 835		if (nfs_page_to_folio(freq) == folio)
 836			return freq->wb_head;
 837	}
 838
 839	return NULL;
 840}
 841
 842/**
 843 * nfs_request_add_commit_list_locked - add request to a commit list
 844 * @req: pointer to a struct nfs_page
 845 * @dst: commit list head
 846 * @cinfo: holds list lock and accounting info
 847 *
 848 * This sets the PG_CLEAN bit, updates the cinfo count of
 849 * number of outstanding requests requiring a commit as well as
 850 * the MM page stats.
 851 *
 852 * The caller must hold NFS_I(cinfo->inode)->commit_mutex, and the
 853 * nfs_page lock.
 854 */
 855void
 856nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
 857			    struct nfs_commit_info *cinfo)
 858{
 859	set_bit(PG_CLEAN, &req->wb_flags);
 860	nfs_list_add_request(req, dst);
 861	atomic_long_inc(&cinfo->mds->ncommit);
 862}
 863EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
 864
 865/**
 866 * nfs_request_add_commit_list - add request to a commit list
 867 * @req: pointer to a struct nfs_page
 868 * @cinfo: holds list lock and accounting info
 869 *
 870 * This sets the PG_CLEAN bit, updates the cinfo count of
 871 * number of outstanding requests requiring a commit as well as
 872 * the MM page stats.
 873 *
 874 * The caller must _not_ hold the cinfo->lock, but must be
 875 * holding the nfs_page lock.
 876 */
 877void
 878nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
 879{
 880	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
 881	nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
 882	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
 883	nfs_folio_mark_unstable(nfs_page_to_folio(req), cinfo);
 
 884}
 885EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
 886
 887/**
 888 * nfs_request_remove_commit_list - Remove request from a commit list
 889 * @req: pointer to a nfs_page
 890 * @cinfo: holds list lock and accounting info
 891 *
 892 * This clears the PG_CLEAN bit, and updates the cinfo's count of
 893 * number of outstanding requests requiring a commit
 894 * It does not update the MM page stats.
 895 *
 896 * The caller _must_ hold the cinfo->lock and the nfs_page lock.
 897 */
 898void
 899nfs_request_remove_commit_list(struct nfs_page *req,
 900			       struct nfs_commit_info *cinfo)
 901{
 902	if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
 903		return;
 904	nfs_list_remove_request(req);
 905	atomic_long_dec(&cinfo->mds->ncommit);
 906}
 907EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
 908
 909static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
 910				      struct inode *inode)
 911{
 912	cinfo->inode = inode;
 913	cinfo->mds = &NFS_I(inode)->commit_info;
 914	cinfo->ds = pnfs_get_ds_info(inode);
 915	cinfo->dreq = NULL;
 916	cinfo->completion_ops = &nfs_commit_completion_ops;
 917}
 918
 919void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 920		    struct inode *inode,
 921		    struct nfs_direct_req *dreq)
 922{
 923	if (dreq)
 924		nfs_init_cinfo_from_dreq(cinfo, dreq);
 925	else
 926		nfs_init_cinfo_from_inode(cinfo, inode);
 927}
 928EXPORT_SYMBOL_GPL(nfs_init_cinfo);
 929
 930/*
 931 * Add a request to the inode's commit list.
 932 */
 933void
 934nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
 935			struct nfs_commit_info *cinfo, u32 ds_commit_idx)
 936{
 937	if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx))
 938		return;
 939	nfs_request_add_commit_list(req, cinfo);
 940}
 941
 942static void nfs_folio_clear_commit(struct folio *folio)
 
 943{
 944	if (folio) {
 945		long nr = folio_nr_pages(folio);
 946
 947		node_stat_mod_folio(folio, NR_WRITEBACK, -nr);
 948		wb_stat_mod(&inode_to_bdi(folio_file_mapping(folio)->host)->wb,
 949			    WB_WRITEBACK, -nr);
 950	}
 951}
 952
 953/* Called holding the request lock on @req */
 954static void nfs_clear_request_commit(struct nfs_commit_info *cinfo,
 955				     struct nfs_page *req)
 956{
 957	if (test_bit(PG_CLEAN, &req->wb_flags)) {
 958		struct nfs_open_context *ctx = nfs_req_openctx(req);
 959		struct inode *inode = d_inode(ctx->dentry);
 
 960
 
 961		mutex_lock(&NFS_I(inode)->commit_mutex);
 962		if (!pnfs_clear_request_commit(req, cinfo)) {
 963			nfs_request_remove_commit_list(req, cinfo);
 964		}
 965		mutex_unlock(&NFS_I(inode)->commit_mutex);
 966		nfs_folio_clear_commit(nfs_page_to_folio(req));
 967	}
 968}
 969
 970int nfs_write_need_commit(struct nfs_pgio_header *hdr)
 971{
 972	if (hdr->verf.committed == NFS_DATA_SYNC)
 973		return hdr->lseg == NULL;
 974	return hdr->verf.committed != NFS_FILE_SYNC;
 975}
 976
 977static void nfs_async_write_init(struct nfs_pgio_header *hdr)
 978{
 979	nfs_io_completion_get(hdr->io_completion);
 980}
 981
 982static void nfs_write_completion(struct nfs_pgio_header *hdr)
 983{
 984	struct nfs_commit_info cinfo;
 985	unsigned long bytes = 0;
 986
 987	if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
 988		goto out;
 989	nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
 990	while (!list_empty(&hdr->pages)) {
 991		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
 992
 993		bytes += req->wb_bytes;
 994		nfs_list_remove_request(req);
 995		if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
 996		    (hdr->good_bytes < bytes)) {
 997			trace_nfs_comp_error(hdr->inode, req, hdr->error);
 998			nfs_mapping_set_error(nfs_page_to_folio(req),
 999					      hdr->error);
1000			goto remove_req;
1001		}
1002		if (nfs_write_need_commit(hdr)) {
1003			/* Reset wb_nio, since the write was successful. */
1004			req->wb_nio = 0;
1005			memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
1006			nfs_mark_request_commit(req, hdr->lseg, &cinfo,
1007				hdr->pgio_mirror_idx);
1008			goto next;
1009		}
1010remove_req:
1011		nfs_inode_remove_request(req);
1012next:
1013		nfs_page_end_writeback(req);
1014		nfs_release_request(req);
1015	}
1016out:
1017	nfs_io_completion_put(hdr->io_completion);
1018	hdr->release(hdr);
1019}
1020
1021unsigned long
1022nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
1023{
1024	return atomic_long_read(&cinfo->mds->ncommit);
1025}
1026
1027/* NFS_I(cinfo->inode)->commit_mutex held by caller */
1028int
1029nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
1030		     struct nfs_commit_info *cinfo, int max)
1031{
1032	struct nfs_page *req, *tmp;
1033	int ret = 0;
1034
 
1035	list_for_each_entry_safe(req, tmp, src, wb_list) {
1036		kref_get(&req->wb_kref);
1037		if (!nfs_lock_request(req)) {
 
 
 
 
 
 
 
 
 
 
1038			nfs_release_request(req);
1039			continue;
 
 
 
1040		}
1041		nfs_request_remove_commit_list(req, cinfo);
1042		clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
1043		nfs_list_add_request(req, dst);
1044		ret++;
1045		if ((ret == max) && !cinfo->dreq)
1046			break;
1047		cond_resched();
1048	}
1049	return ret;
1050}
1051EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
1052
1053/*
1054 * nfs_scan_commit - Scan an inode for commit requests
1055 * @inode: NFS inode to scan
1056 * @dst: mds destination list
1057 * @cinfo: mds and ds lists of reqs ready to commit
1058 *
1059 * Moves requests from the inode's 'commit' request list.
1060 * The requests are *not* checked to ensure that they form a contiguous set.
1061 */
1062int
1063nfs_scan_commit(struct inode *inode, struct list_head *dst,
1064		struct nfs_commit_info *cinfo)
1065{
1066	int ret = 0;
1067
1068	if (!atomic_long_read(&cinfo->mds->ncommit))
1069		return 0;
1070	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
1071	if (atomic_long_read(&cinfo->mds->ncommit) > 0) {
1072		const int max = INT_MAX;
1073
1074		ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
1075					   cinfo, max);
1076		ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
1077	}
1078	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
1079	return ret;
1080}
1081
1082/*
1083 * Search for an existing write request, and attempt to update
1084 * it to reflect a new dirty region on a given page.
1085 *
1086 * If the attempt fails, then the existing request is flushed out
1087 * to disk.
1088 */
1089static struct nfs_page *nfs_try_to_update_request(struct folio *folio,
1090						  unsigned int offset,
1091						  unsigned int bytes)
 
1092{
1093	struct nfs_page *req;
1094	unsigned int rqend;
1095	unsigned int end;
1096	int error;
1097
1098	end = offset + bytes;
1099
1100	req = nfs_lock_and_join_requests(folio);
1101	if (IS_ERR_OR_NULL(req))
1102		return req;
1103
1104	rqend = req->wb_offset + req->wb_bytes;
1105	/*
1106	 * Tell the caller to flush out the request if
1107	 * the offsets are non-contiguous.
1108	 * Note: nfs_flush_incompatible() will already
1109	 * have flushed out requests having wrong owners.
1110	 */
1111	if (offset > rqend || end < req->wb_offset)
1112		goto out_flushme;
1113
1114	/* Okay, the request matches. Update the region */
1115	if (offset < req->wb_offset) {
1116		req->wb_offset = offset;
1117		req->wb_pgbase = offset;
1118	}
1119	if (end > rqend)
1120		req->wb_bytes = end - req->wb_offset;
1121	else
1122		req->wb_bytes = rqend - req->wb_offset;
1123	req->wb_nio = 0;
1124	return req;
1125out_flushme:
1126	/*
1127	 * Note: we mark the request dirty here because
1128	 * nfs_lock_and_join_requests() cannot preserve
1129	 * commit flags, so we have to replay the write.
1130	 */
1131	nfs_mark_request_dirty(req);
1132	nfs_unlock_and_release_request(req);
1133	error = nfs_wb_folio(folio_file_mapping(folio)->host, folio);
1134	return (error < 0) ? ERR_PTR(error) : NULL;
1135}
1136
1137/*
1138 * Try to update an existing write request, or create one if there is none.
1139 *
1140 * Note: Should always be called with the Page Lock held to prevent races
1141 * if we have to add a new request. Also assumes that the caller has
1142 * already called nfs_flush_incompatible() if necessary.
1143 */
1144static struct nfs_page *nfs_setup_write_request(struct nfs_open_context *ctx,
1145						struct folio *folio,
1146						unsigned int offset,
1147						unsigned int bytes)
1148{
1149	struct nfs_page *req;
 
1150
1151	req = nfs_try_to_update_request(folio, offset, bytes);
1152	if (req != NULL)
1153		goto out;
1154	req = nfs_page_create_from_folio(ctx, folio, offset, bytes);
1155	if (IS_ERR(req))
1156		goto out;
1157	nfs_inode_add_request(req);
1158out:
1159	return req;
1160}
1161
1162static int nfs_writepage_setup(struct nfs_open_context *ctx,
1163			       struct folio *folio, unsigned int offset,
1164			       unsigned int count)
1165{
1166	struct nfs_page *req;
1167
1168	req = nfs_setup_write_request(ctx, folio, offset, count);
1169	if (IS_ERR(req))
1170		return PTR_ERR(req);
1171	/* Update file length */
1172	nfs_grow_file(folio, offset, count);
1173	nfs_mark_uptodate(req);
1174	nfs_mark_request_dirty(req);
1175	nfs_unlock_and_release_request(req);
1176	return 0;
1177}
1178
1179int nfs_flush_incompatible(struct file *file, struct folio *folio)
1180{
1181	struct nfs_open_context *ctx = nfs_file_open_context(file);
1182	struct nfs_lock_context *l_ctx;
1183	struct file_lock_context *flctx = locks_inode_context(file_inode(file));
1184	struct nfs_page	*req;
1185	int do_flush, status;
1186	/*
1187	 * Look for a request corresponding to this page. If there
1188	 * is one, and it belongs to another file, we flush it out
1189	 * before we try to copy anything into the page. Do this
1190	 * due to the lack of an ACCESS-type call in NFSv2.
1191	 * Also do the same if we find a request from an existing
1192	 * dropped page.
1193	 */
1194	do {
1195		req = nfs_folio_find_head_request(folio);
1196		if (req == NULL)
1197			return 0;
1198		l_ctx = req->wb_lock_context;
1199		do_flush = nfs_page_to_folio(req) != folio ||
1200			   !nfs_match_open_context(nfs_req_openctx(req), ctx);
1201		if (l_ctx && flctx &&
1202		    !(list_empty_careful(&flctx->flc_posix) &&
1203		      list_empty_careful(&flctx->flc_flock))) {
1204			do_flush |= l_ctx->lockowner != current->files;
1205		}
1206		nfs_release_request(req);
1207		if (!do_flush)
1208			return 0;
1209		status = nfs_wb_folio(folio_file_mapping(folio)->host, folio);
1210	} while (status == 0);
1211	return status;
1212}
1213
1214/*
1215 * Avoid buffered writes when a open context credential's key would
1216 * expire soon.
1217 *
1218 * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
1219 *
1220 * Return 0 and set a credential flag which triggers the inode to flush
1221 * and performs  NFS_FILE_SYNC writes if the key will expired within
1222 * RPC_KEY_EXPIRE_TIMEO.
1223 */
1224int
1225nfs_key_timeout_notify(struct file *filp, struct inode *inode)
1226{
1227	struct nfs_open_context *ctx = nfs_file_open_context(filp);
1228
1229	if (nfs_ctx_key_to_expire(ctx, inode) &&
1230	    !rcu_access_pointer(ctx->ll_cred))
1231		/* Already expired! */
1232		return -EACCES;
1233	return 0;
1234}
1235
1236/*
1237 * Test if the open context credential key is marked to expire soon.
1238 */
1239bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx, struct inode *inode)
1240{
1241	struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
1242	struct rpc_cred *cred, *new, *old = NULL;
1243	struct auth_cred acred = {
1244		.cred = ctx->cred,
1245	};
1246	bool ret = false;
1247
1248	rcu_read_lock();
1249	cred = rcu_dereference(ctx->ll_cred);
1250	if (cred && !(cred->cr_ops->crkey_timeout &&
1251		      cred->cr_ops->crkey_timeout(cred)))
1252		goto out;
1253	rcu_read_unlock();
1254
1255	new = auth->au_ops->lookup_cred(auth, &acred, 0);
1256	if (new == cred) {
1257		put_rpccred(new);
1258		return true;
1259	}
1260	if (IS_ERR_OR_NULL(new)) {
1261		new = NULL;
1262		ret = true;
1263	} else if (new->cr_ops->crkey_timeout &&
1264		   new->cr_ops->crkey_timeout(new))
1265		ret = true;
1266
1267	rcu_read_lock();
1268	old = rcu_dereference_protected(xchg(&ctx->ll_cred,
1269					     RCU_INITIALIZER(new)), 1);
1270out:
1271	rcu_read_unlock();
1272	put_rpccred(old);
1273	return ret;
1274}
1275
1276/*
1277 * If the page cache is marked as unsafe or invalid, then we can't rely on
1278 * the PageUptodate() flag. In this case, we will need to turn off
1279 * write optimisations that depend on the page contents being correct.
1280 */
1281static bool nfs_folio_write_uptodate(struct folio *folio, unsigned int pagelen)
1282{
1283	struct inode *inode = folio_file_mapping(folio)->host;
1284	struct nfs_inode *nfsi = NFS_I(inode);
1285
1286	if (nfs_have_delegated_attributes(inode))
1287		goto out;
1288	if (nfsi->cache_validity &
1289	    (NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_SIZE))
1290		return false;
1291	smp_rmb();
1292	if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags) && pagelen != 0)
1293		return false;
1294out:
1295	if (nfsi->cache_validity & NFS_INO_INVALID_DATA && pagelen != 0)
1296		return false;
1297	return folio_test_uptodate(folio) != 0;
1298}
1299
1300static bool
1301is_whole_file_wrlock(struct file_lock *fl)
1302{
1303	return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX &&
1304			fl->fl_type == F_WRLCK;
1305}
1306
1307/* If we know the page is up to date, and we're not using byte range locks (or
1308 * if we have the whole file locked for writing), it may be more efficient to
1309 * extend the write to cover the entire page in order to avoid fragmentation
1310 * inefficiencies.
1311 *
1312 * If the file is opened for synchronous writes then we can just skip the rest
1313 * of the checks.
1314 */
1315static int nfs_can_extend_write(struct file *file, struct folio *folio,
1316				unsigned int pagelen)
1317{
1318	struct inode *inode = file_inode(file);
1319	struct file_lock_context *flctx = locks_inode_context(inode);
1320	struct file_lock *fl;
1321	int ret;
 
 
1322
1323	if (file->f_flags & O_DSYNC)
1324		return 0;
1325	if (!nfs_folio_write_uptodate(folio, pagelen))
1326		return 0;
1327	if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
1328		return 1;
1329	if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
1330		       list_empty_careful(&flctx->flc_posix)))
1331		return 1;
1332
1333	/* Check to see if there are whole file write locks */
1334	ret = 0;
1335	spin_lock(&flctx->flc_lock);
1336	if (!list_empty(&flctx->flc_posix)) {
1337		fl = list_first_entry(&flctx->flc_posix, struct file_lock,
1338					fl_list);
1339		if (is_whole_file_wrlock(fl))
1340			ret = 1;
1341	} else if (!list_empty(&flctx->flc_flock)) {
1342		fl = list_first_entry(&flctx->flc_flock, struct file_lock,
1343					fl_list);
1344		if (fl->fl_type == F_WRLCK)
1345			ret = 1;
1346	}
1347	spin_unlock(&flctx->flc_lock);
1348	return ret;
1349}
1350
1351/*
1352 * Update and possibly write a cached page of an NFS file.
1353 *
1354 * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
1355 * things with a page scheduled for an RPC call (e.g. invalidate it).
1356 */
1357int nfs_update_folio(struct file *file, struct folio *folio,
1358		     unsigned int offset, unsigned int count)
1359{
1360	struct nfs_open_context *ctx = nfs_file_open_context(file);
1361	struct address_space *mapping = folio_file_mapping(folio);
1362	struct inode *inode = mapping->host;
1363	unsigned int pagelen = nfs_folio_length(folio);
1364	int		status = 0;
1365
1366	nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
1367
1368	dprintk("NFS:       nfs_update_folio(%pD2 %d@%lld)\n", file, count,
1369		(long long)(folio_file_pos(folio) + offset));
1370
1371	if (!count)
1372		goto out;
1373
1374	if (nfs_can_extend_write(file, folio, pagelen)) {
1375		count = max(count + offset, pagelen);
1376		offset = 0;
1377	}
1378
1379	status = nfs_writepage_setup(ctx, folio, offset, count);
1380	if (status < 0)
1381		nfs_set_pageerror(mapping);
 
 
1382out:
1383	dprintk("NFS:       nfs_update_folio returns %d (isize %lld)\n",
1384			status, (long long)i_size_read(inode));
1385	return status;
1386}
1387
1388static int flush_task_priority(int how)
1389{
1390	switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
1391		case FLUSH_HIGHPRI:
1392			return RPC_PRIORITY_HIGH;
1393		case FLUSH_LOWPRI:
1394			return RPC_PRIORITY_LOW;
1395	}
1396	return RPC_PRIORITY_NORMAL;
1397}
1398
1399static void nfs_initiate_write(struct nfs_pgio_header *hdr,
1400			       struct rpc_message *msg,
1401			       const struct nfs_rpc_ops *rpc_ops,
1402			       struct rpc_task_setup *task_setup_data, int how)
1403{
1404	int priority = flush_task_priority(how);
1405
1406	if (IS_SWAPFILE(hdr->inode))
1407		task_setup_data->flags |= RPC_TASK_SWAPPER;
1408	task_setup_data->priority = priority;
1409	rpc_ops->write_setup(hdr, msg, &task_setup_data->rpc_client);
1410	trace_nfs_initiate_write(hdr);
1411}
1412
1413/* If a nfs_flush_* function fails, it should remove reqs from @head and
1414 * call this on each, which will prepare them to be retried on next
1415 * writeback using standard nfs.
1416 */
1417static void nfs_redirty_request(struct nfs_page *req)
1418{
1419	struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req));
1420
1421	/* Bump the transmission count */
1422	req->wb_nio++;
1423	nfs_mark_request_dirty(req);
1424	atomic_long_inc(&nfsi->redirtied_pages);
1425	nfs_page_end_writeback(req);
1426	nfs_release_request(req);
1427}
1428
1429static void nfs_async_write_error(struct list_head *head, int error)
1430{
1431	struct nfs_page	*req;
1432
1433	while (!list_empty(head)) {
1434		req = nfs_list_entry(head->next);
1435		nfs_list_remove_request(req);
1436		if (nfs_error_is_fatal_on_server(error))
1437			nfs_write_error(req, error);
1438		else
1439			nfs_redirty_request(req);
1440	}
1441}
1442
1443static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)
1444{
1445	nfs_async_write_error(&hdr->pages, 0);
 
 
1446}
1447
1448static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
1449	.init_hdr = nfs_async_write_init,
1450	.error_cleanup = nfs_async_write_error,
1451	.completion = nfs_write_completion,
1452	.reschedule_io = nfs_async_write_reschedule_io,
1453};
1454
1455void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1456			       struct inode *inode, int ioflags, bool force_mds,
1457			       const struct nfs_pgio_completion_ops *compl_ops)
1458{
1459	struct nfs_server *server = NFS_SERVER(inode);
1460	const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
1461
1462#ifdef CONFIG_NFS_V4_1
1463	if (server->pnfs_curr_ld && !force_mds)
1464		pg_ops = server->pnfs_curr_ld->pg_write_ops;
1465#endif
1466	nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops,
1467			server->wsize, ioflags);
1468}
1469EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
1470
1471void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1472{
1473	struct nfs_pgio_mirror *mirror;
1474
1475	if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
1476		pgio->pg_ops->pg_cleanup(pgio);
1477
1478	pgio->pg_ops = &nfs_pgio_rw_ops;
1479
1480	nfs_pageio_stop_mirroring(pgio);
1481
1482	mirror = &pgio->pg_mirrors[0];
1483	mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1484}
1485EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1486
1487
1488void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1489{
1490	struct nfs_commit_data *data = calldata;
1491
1492	NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1493}
1494
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1495static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
1496		struct nfs_fattr *fattr)
1497{
1498	struct nfs_pgio_args *argp = &hdr->args;
1499	struct nfs_pgio_res *resp = &hdr->res;
1500	u64 size = argp->offset + resp->count;
1501
1502	if (!(fattr->valid & NFS_ATTR_FATTR_SIZE))
1503		fattr->size = size;
1504	if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) {
1505		fattr->valid &= ~NFS_ATTR_FATTR_SIZE;
1506		return;
1507	}
1508	if (size != fattr->size)
1509		return;
1510	/* Set attribute barrier */
1511	nfs_fattr_set_barrier(fattr);
1512	/* ...and update size */
1513	fattr->valid |= NFS_ATTR_FATTR_SIZE;
1514}
1515
1516void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
1517{
1518	struct nfs_fattr *fattr = &hdr->fattr;
1519	struct inode *inode = hdr->inode;
1520
1521	spin_lock(&inode->i_lock);
1522	nfs_writeback_check_extend(hdr, fattr);
1523	nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
1524	spin_unlock(&inode->i_lock);
1525}
1526EXPORT_SYMBOL_GPL(nfs_writeback_update_inode);
1527
1528/*
1529 * This function is called when the WRITE call is complete.
1530 */
1531static int nfs_writeback_done(struct rpc_task *task,
1532			      struct nfs_pgio_header *hdr,
1533			      struct inode *inode)
1534{
1535	int status;
1536
1537	/*
1538	 * ->write_done will attempt to use post-op attributes to detect
1539	 * conflicting writes by other clients.  A strict interpretation
1540	 * of close-to-open would allow us to continue caching even if
1541	 * another writer had changed the file, but some applications
1542	 * depend on tighter cache coherency when writing.
1543	 */
1544	status = NFS_PROTO(inode)->write_done(task, hdr);
1545	if (status != 0)
1546		return status;
1547
1548	nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count);
1549	trace_nfs_writeback_done(task, hdr);
1550
1551	if (task->tk_status >= 0) {
1552		enum nfs3_stable_how committed = hdr->res.verf->committed;
1553
1554		if (committed == NFS_UNSTABLE) {
1555			/*
1556			 * We have some uncommitted data on the server at
1557			 * this point, so ensure that we keep track of that
1558			 * fact irrespective of what later writes do.
1559			 */
1560			set_bit(NFS_IOHDR_UNSTABLE_WRITES, &hdr->flags);
1561		}
1562
1563		if (committed < hdr->args.stable) {
1564			/* We tried a write call, but the server did not
1565			 * commit data to stable storage even though we
1566			 * requested it.
1567			 * Note: There is a known bug in Tru64 < 5.0 in which
1568			 *	 the server reports NFS_DATA_SYNC, but performs
1569			 *	 NFS_FILE_SYNC. We therefore implement this checking
1570			 *	 as a dprintk() in order to avoid filling syslog.
1571			 */
1572			static unsigned long    complain;
1573
1574			/* Note this will print the MDS for a DS write */
1575			if (time_before(complain, jiffies)) {
1576				dprintk("NFS:       faulty NFS server %s:"
1577					" (committed = %d) != (stable = %d)\n",
1578					NFS_SERVER(inode)->nfs_client->cl_hostname,
1579					committed, hdr->args.stable);
1580				complain = jiffies + 300 * HZ;
1581			}
1582		}
1583	}
1584
1585	/* Deal with the suid/sgid bit corner case */
1586	if (nfs_should_remove_suid(inode)) {
1587		spin_lock(&inode->i_lock);
1588		nfs_set_cache_invalid(inode, NFS_INO_INVALID_MODE);
1589		spin_unlock(&inode->i_lock);
1590	}
1591	return 0;
1592}
1593
1594/*
1595 * This function is called when the WRITE call is complete.
1596 */
1597static void nfs_writeback_result(struct rpc_task *task,
1598				 struct nfs_pgio_header *hdr)
1599{
1600	struct nfs_pgio_args	*argp = &hdr->args;
1601	struct nfs_pgio_res	*resp = &hdr->res;
1602
1603	if (resp->count < argp->count) {
1604		static unsigned long    complain;
1605
1606		/* This a short write! */
1607		nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE);
1608
1609		/* Has the server at least made some progress? */
1610		if (resp->count == 0) {
1611			if (time_before(complain, jiffies)) {
1612				printk(KERN_WARNING
1613				       "NFS: Server wrote zero bytes, expected %u.\n",
1614				       argp->count);
1615				complain = jiffies + 300 * HZ;
1616			}
1617			nfs_set_pgio_error(hdr, -EIO, argp->offset);
1618			task->tk_status = -EIO;
1619			return;
1620		}
1621
1622		/* For non rpc-based layout drivers, retry-through-MDS */
1623		if (!task->tk_ops) {
1624			hdr->pnfs_error = -EAGAIN;
1625			return;
1626		}
1627
1628		/* Was this an NFSv2 write or an NFSv3 stable write? */
1629		if (resp->verf->committed != NFS_UNSTABLE) {
1630			/* Resend from where the server left off */
1631			hdr->mds_offset += resp->count;
1632			argp->offset += resp->count;
1633			argp->pgbase += resp->count;
1634			argp->count -= resp->count;
1635		} else {
1636			/* Resend as a stable write in order to avoid
1637			 * headaches in the case of a server crash.
1638			 */
1639			argp->stable = NFS_FILE_SYNC;
1640		}
1641		resp->count = 0;
1642		resp->verf->committed = 0;
1643		rpc_restart_call_prepare(task);
1644	}
1645}
1646
1647static int wait_on_commit(struct nfs_mds_commit_info *cinfo)
1648{
1649	return wait_var_event_killable(&cinfo->rpcs_out,
1650				       !atomic_read(&cinfo->rpcs_out));
1651}
1652
1653static void nfs_commit_begin(struct nfs_mds_commit_info *cinfo)
1654{
1655	atomic_inc(&cinfo->rpcs_out);
1656}
1657
1658bool nfs_commit_end(struct nfs_mds_commit_info *cinfo)
1659{
1660	if (atomic_dec_and_test(&cinfo->rpcs_out)) {
1661		wake_up_var(&cinfo->rpcs_out);
1662		return true;
1663	}
1664	return false;
1665}
1666
1667void nfs_commitdata_release(struct nfs_commit_data *data)
1668{
1669	put_nfs_open_context(data->context);
1670	nfs_commit_free(data);
1671}
1672EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1673
1674int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
1675			const struct nfs_rpc_ops *nfs_ops,
1676			const struct rpc_call_ops *call_ops,
1677			int how, int flags)
1678{
1679	struct rpc_task *task;
1680	int priority = flush_task_priority(how);
1681	struct rpc_message msg = {
1682		.rpc_argp = &data->args,
1683		.rpc_resp = &data->res,
1684		.rpc_cred = data->cred,
1685	};
1686	struct rpc_task_setup task_setup_data = {
1687		.task = &data->task,
1688		.rpc_client = clnt,
1689		.rpc_message = &msg,
1690		.callback_ops = call_ops,
1691		.callback_data = data,
1692		.workqueue = nfsiod_workqueue,
1693		.flags = RPC_TASK_ASYNC | flags,
1694		.priority = priority,
1695	};
1696
1697	if (nfs_server_capable(data->inode, NFS_CAP_MOVEABLE))
1698		task_setup_data.flags |= RPC_TASK_MOVEABLE;
1699
1700	/* Set up the initial task struct.  */
1701	nfs_ops->commit_setup(data, &msg, &task_setup_data.rpc_client);
1702	trace_nfs_initiate_commit(data);
1703
1704	dprintk("NFS: initiated commit call\n");
1705
1706	task = rpc_run_task(&task_setup_data);
1707	if (IS_ERR(task))
1708		return PTR_ERR(task);
1709	if (how & FLUSH_SYNC)
1710		rpc_wait_for_completion_task(task);
1711	rpc_put_task(task);
1712	return 0;
1713}
1714EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1715
1716static loff_t nfs_get_lwb(struct list_head *head)
1717{
1718	loff_t lwb = 0;
1719	struct nfs_page *req;
1720
1721	list_for_each_entry(req, head, wb_list)
1722		if (lwb < (req_offset(req) + req->wb_bytes))
1723			lwb = req_offset(req) + req->wb_bytes;
1724
1725	return lwb;
1726}
1727
1728/*
1729 * Set up the argument/result storage required for the RPC call.
1730 */
1731void nfs_init_commit(struct nfs_commit_data *data,
1732		     struct list_head *head,
1733		     struct pnfs_layout_segment *lseg,
1734		     struct nfs_commit_info *cinfo)
1735{
1736	struct nfs_page *first;
1737	struct nfs_open_context *ctx;
1738	struct inode *inode;
1739
1740	/* Set up the RPC argument and reply structs
1741	 * NB: take care not to mess about with data->commit et al. */
1742
1743	if (head)
1744		list_splice_init(head, &data->pages);
1745
1746	first = nfs_list_entry(data->pages.next);
1747	ctx = nfs_req_openctx(first);
1748	inode = d_inode(ctx->dentry);
1749
1750	data->inode	  = inode;
1751	data->cred	  = ctx->cred;
1752	data->lseg	  = lseg; /* reference transferred */
1753	/* only set lwb for pnfs commit */
1754	if (lseg)
1755		data->lwb = nfs_get_lwb(&data->pages);
1756	data->mds_ops     = &nfs_commit_ops;
1757	data->completion_ops = cinfo->completion_ops;
1758	data->dreq	  = cinfo->dreq;
1759
1760	data->args.fh     = NFS_FH(data->inode);
1761	/* Note: we always request a commit of the entire inode */
1762	data->args.offset = 0;
1763	data->args.count  = 0;
1764	data->context     = get_nfs_open_context(ctx);
1765	data->res.fattr   = &data->fattr;
1766	data->res.verf    = &data->verf;
1767	nfs_fattr_init(&data->fattr);
1768	nfs_commit_begin(cinfo->mds);
1769}
1770EXPORT_SYMBOL_GPL(nfs_init_commit);
1771
1772void nfs_retry_commit(struct list_head *page_list,
1773		      struct pnfs_layout_segment *lseg,
1774		      struct nfs_commit_info *cinfo,
1775		      u32 ds_commit_idx)
1776{
1777	struct nfs_page *req;
1778
1779	while (!list_empty(page_list)) {
1780		req = nfs_list_entry(page_list->next);
1781		nfs_list_remove_request(req);
1782		nfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx);
1783		nfs_folio_clear_commit(nfs_page_to_folio(req));
 
1784		nfs_unlock_and_release_request(req);
1785	}
1786}
1787EXPORT_SYMBOL_GPL(nfs_retry_commit);
1788
1789static void nfs_commit_resched_write(struct nfs_commit_info *cinfo,
1790				     struct nfs_page *req)
 
1791{
1792	struct folio *folio = nfs_page_to_folio(req);
1793
1794	filemap_dirty_folio(folio_mapping(folio), folio);
1795}
1796
1797/*
1798 * Commit dirty pages
1799 */
1800static int
1801nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1802		struct nfs_commit_info *cinfo)
1803{
1804	struct nfs_commit_data	*data;
1805	unsigned short task_flags = 0;
1806
1807	/* another commit raced with us */
1808	if (list_empty(head))
1809		return 0;
1810
1811	data = nfs_commitdata_alloc();
1812	if (!data) {
1813		nfs_retry_commit(head, NULL, cinfo, -1);
1814		return -ENOMEM;
1815	}
1816
1817	/* Set up the argument struct */
1818	nfs_init_commit(data, head, NULL, cinfo);
1819	if (NFS_SERVER(inode)->nfs_client->cl_minorversion)
1820		task_flags = RPC_TASK_MOVEABLE;
1821	return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode),
1822				   data->mds_ops, how,
1823				   RPC_TASK_CRED_NOREF | task_flags);
1824}
1825
1826/*
1827 * COMMIT call returned
1828 */
1829static void nfs_commit_done(struct rpc_task *task, void *calldata)
1830{
1831	struct nfs_commit_data	*data = calldata;
1832
 
 
 
1833	/* Call the NFS version-specific code */
1834	NFS_PROTO(data->inode)->commit_done(task, data);
1835	trace_nfs_commit_done(task, data);
1836}
1837
1838static void nfs_commit_release_pages(struct nfs_commit_data *data)
1839{
1840	const struct nfs_writeverf *verf = data->res.verf;
1841	struct nfs_page	*req;
1842	int status = data->task.tk_status;
1843	struct nfs_commit_info cinfo;
1844	struct nfs_server *nfss;
1845	struct folio *folio;
1846
1847	while (!list_empty(&data->pages)) {
1848		req = nfs_list_entry(data->pages.next);
1849		nfs_list_remove_request(req);
1850		folio = nfs_page_to_folio(req);
1851		nfs_folio_clear_commit(folio);
1852
1853		dprintk("NFS:       commit (%s/%llu %d@%lld)",
1854			nfs_req_openctx(req)->dentry->d_sb->s_id,
1855			(unsigned long long)NFS_FILEID(d_inode(nfs_req_openctx(req)->dentry)),
1856			req->wb_bytes,
1857			(long long)req_offset(req));
1858		if (status < 0) {
1859			if (folio) {
1860				trace_nfs_commit_error(data->inode, req,
1861						       status);
1862				nfs_mapping_set_error(folio, status);
1863				nfs_inode_remove_request(req);
1864			}
1865			dprintk_cont(", error = %d\n", status);
1866			goto next;
1867		}
1868
1869		/* Okay, COMMIT succeeded, apparently. Check the verifier
1870		 * returned by the server against all stored verfs. */
1871		if (nfs_write_match_verf(verf, req)) {
1872			/* We have a match */
1873			if (folio)
1874				nfs_inode_remove_request(req);
1875			dprintk_cont(" OK\n");
1876			goto next;
1877		}
1878		/* We have a mismatch. Write the page again */
1879		dprintk_cont(" mismatch\n");
1880		nfs_mark_request_dirty(req);
1881		atomic_long_inc(&NFS_I(data->inode)->redirtied_pages);
1882	next:
1883		nfs_unlock_and_release_request(req);
1884		/* Latency breaker */
1885		cond_resched();
1886	}
1887	nfss = NFS_SERVER(data->inode);
1888	if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
1889		nfss->write_congested = 0;
1890
1891	nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1892	nfs_commit_end(cinfo.mds);
1893}
1894
1895static void nfs_commit_release(void *calldata)
1896{
1897	struct nfs_commit_data *data = calldata;
1898
1899	data->completion_ops->completion(data);
1900	nfs_commitdata_release(calldata);
1901}
1902
1903static const struct rpc_call_ops nfs_commit_ops = {
1904	.rpc_call_prepare = nfs_commit_prepare,
1905	.rpc_call_done = nfs_commit_done,
1906	.rpc_release = nfs_commit_release,
1907};
1908
1909static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1910	.completion = nfs_commit_release_pages,
1911	.resched_write = nfs_commit_resched_write,
1912};
1913
1914int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1915			    int how, struct nfs_commit_info *cinfo)
1916{
1917	int status;
1918
1919	status = pnfs_commit_list(inode, head, how, cinfo);
1920	if (status == PNFS_NOT_ATTEMPTED)
1921		status = nfs_commit_list(inode, head, how, cinfo);
1922	return status;
1923}
1924
1925static int __nfs_commit_inode(struct inode *inode, int how,
1926		struct writeback_control *wbc)
1927{
1928	LIST_HEAD(head);
1929	struct nfs_commit_info cinfo;
1930	int may_wait = how & FLUSH_SYNC;
1931	int ret, nscan;
1932
1933	how &= ~FLUSH_SYNC;
1934	nfs_init_cinfo_from_inode(&cinfo, inode);
1935	nfs_commit_begin(cinfo.mds);
1936	for (;;) {
1937		ret = nscan = nfs_scan_commit(inode, &head, &cinfo);
1938		if (ret <= 0)
1939			break;
1940		ret = nfs_generic_commit_list(inode, &head, how, &cinfo);
1941		if (ret < 0)
1942			break;
1943		ret = 0;
1944		if (wbc && wbc->sync_mode == WB_SYNC_NONE) {
1945			if (nscan < wbc->nr_to_write)
1946				wbc->nr_to_write -= nscan;
1947			else
1948				wbc->nr_to_write = 0;
1949		}
1950		if (nscan < INT_MAX)
1951			break;
1952		cond_resched();
1953	}
1954	nfs_commit_end(cinfo.mds);
1955	if (ret || !may_wait)
1956		return ret;
1957	return wait_on_commit(cinfo.mds);
1958}
1959
1960int nfs_commit_inode(struct inode *inode, int how)
1961{
1962	return __nfs_commit_inode(inode, how, NULL);
1963}
1964EXPORT_SYMBOL_GPL(nfs_commit_inode);
1965
1966int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1967{
1968	struct nfs_inode *nfsi = NFS_I(inode);
1969	int flags = FLUSH_SYNC;
1970	int ret = 0;
1971
1972	if (wbc->sync_mode == WB_SYNC_NONE) {
1973		/* no commits means nothing needs to be done */
1974		if (!atomic_long_read(&nfsi->commit_info.ncommit))
1975			goto check_requests_outstanding;
1976
1977		/* Don't commit yet if this is a non-blocking flush and there
1978		 * are a lot of outstanding writes for this mapping.
1979		 */
1980		if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))
1981			goto out_mark_dirty;
1982
1983		/* don't wait for the COMMIT response */
1984		flags = 0;
1985	}
1986
1987	ret = __nfs_commit_inode(inode, flags, wbc);
1988	if (!ret) {
1989		if (flags & FLUSH_SYNC)
1990			return 0;
1991	} else if (atomic_long_read(&nfsi->commit_info.ncommit))
1992		goto out_mark_dirty;
1993
1994check_requests_outstanding:
1995	if (!atomic_read(&nfsi->commit_info.rpcs_out))
1996		return ret;
1997out_mark_dirty:
1998	__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1999	return ret;
2000}
2001EXPORT_SYMBOL_GPL(nfs_write_inode);
2002
2003/*
2004 * Wrapper for filemap_write_and_wait_range()
2005 *
2006 * Needed for pNFS in order to ensure data becomes visible to the
2007 * client.
2008 */
2009int nfs_filemap_write_and_wait_range(struct address_space *mapping,
2010		loff_t lstart, loff_t lend)
2011{
2012	int ret;
2013
2014	ret = filemap_write_and_wait_range(mapping, lstart, lend);
2015	if (ret == 0)
2016		ret = pnfs_sync_inode(mapping->host, true);
2017	return ret;
2018}
2019EXPORT_SYMBOL_GPL(nfs_filemap_write_and_wait_range);
2020
2021/*
2022 * flush the inode to disk.
2023 */
2024int nfs_wb_all(struct inode *inode)
2025{
2026	int ret;
2027
2028	trace_nfs_writeback_inode_enter(inode);
2029
2030	ret = filemap_write_and_wait(inode->i_mapping);
2031	if (ret)
2032		goto out;
2033	ret = nfs_commit_inode(inode, FLUSH_SYNC);
2034	if (ret < 0)
2035		goto out;
2036	pnfs_sync_inode(inode, true);
2037	ret = 0;
2038
2039out:
2040	trace_nfs_writeback_inode_exit(inode, ret);
2041	return ret;
2042}
2043EXPORT_SYMBOL_GPL(nfs_wb_all);
2044
2045int nfs_wb_folio_cancel(struct inode *inode, struct folio *folio)
2046{
2047	struct nfs_page *req;
2048	int ret = 0;
2049
2050	folio_wait_writeback(folio);
2051
2052	/* blocking call to cancel all requests and join to a single (head)
2053	 * request */
2054	req = nfs_lock_and_join_requests(folio);
2055
2056	if (IS_ERR(req)) {
2057		ret = PTR_ERR(req);
2058	} else if (req) {
2059		/* all requests from this folio have been cancelled by
2060		 * nfs_lock_and_join_requests, so just remove the head
2061		 * request from the inode / page_private pointer and
2062		 * release it */
2063		nfs_inode_remove_request(req);
2064		nfs_unlock_and_release_request(req);
2065	}
2066
2067	return ret;
2068}
2069
2070/**
2071 * nfs_wb_folio - Write back all requests on one page
2072 * @inode: pointer to page
2073 * @folio: pointer to folio
2074 *
2075 * Assumes that the folio has been locked by the caller, and will
2076 * not unlock it.
2077 */
2078int nfs_wb_folio(struct inode *inode, struct folio *folio)
2079{
2080	loff_t range_start = folio_file_pos(folio);
2081	loff_t range_end = range_start + (loff_t)folio_size(folio) - 1;
2082	struct writeback_control wbc = {
2083		.sync_mode = WB_SYNC_ALL,
2084		.nr_to_write = 0,
2085		.range_start = range_start,
2086		.range_end = range_end,
2087	};
2088	int ret;
2089
2090	trace_nfs_writeback_folio(inode, folio);
2091
2092	for (;;) {
2093		folio_wait_writeback(folio);
2094		if (folio_clear_dirty_for_io(folio)) {
2095			ret = nfs_writepage_locked(folio, &wbc);
2096			if (ret < 0)
2097				goto out_error;
2098			continue;
2099		}
2100		ret = 0;
2101		if (!folio_test_private(folio))
2102			break;
2103		ret = nfs_commit_inode(inode, FLUSH_SYNC);
2104		if (ret < 0)
2105			goto out_error;
2106	}
2107out_error:
2108	trace_nfs_writeback_folio_done(inode, folio, ret);
2109	return ret;
2110}
2111
2112#ifdef CONFIG_MIGRATION
2113int nfs_migrate_folio(struct address_space *mapping, struct folio *dst,
2114		struct folio *src, enum migrate_mode mode)
2115{
2116	/*
2117	 * If the private flag is set, the folio is currently associated with
2118	 * an in-progress read or write request. Don't try to migrate it.
2119	 *
2120	 * FIXME: we could do this in principle, but we'll need a way to ensure
2121	 *        that we can safely release the inode reference while holding
2122	 *        the folio lock.
2123	 */
2124	if (folio_test_private(src))
2125		return -EBUSY;
2126
2127	if (folio_test_fscache(src)) {
2128		if (mode == MIGRATE_ASYNC)
2129			return -EBUSY;
2130		folio_wait_fscache(src);
2131	}
2132
2133	return migrate_folio(mapping, dst, src, mode);
2134}
2135#endif
2136
2137int __init nfs_init_writepagecache(void)
2138{
2139	nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
2140					     sizeof(struct nfs_pgio_header),
2141					     0, SLAB_HWCACHE_ALIGN,
2142					     NULL);
2143	if (nfs_wdata_cachep == NULL)
2144		return -ENOMEM;
2145
2146	nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
2147						     nfs_wdata_cachep);
2148	if (nfs_wdata_mempool == NULL)
2149		goto out_destroy_write_cache;
2150
2151	nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
2152					     sizeof(struct nfs_commit_data),
2153					     0, SLAB_HWCACHE_ALIGN,
2154					     NULL);
2155	if (nfs_cdata_cachep == NULL)
2156		goto out_destroy_write_mempool;
2157
2158	nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
2159						      nfs_cdata_cachep);
2160	if (nfs_commit_mempool == NULL)
2161		goto out_destroy_commit_cache;
2162
2163	/*
2164	 * NFS congestion size, scale with available memory.
2165	 *
2166	 *  64MB:    8192k
2167	 * 128MB:   11585k
2168	 * 256MB:   16384k
2169	 * 512MB:   23170k
2170	 *   1GB:   32768k
2171	 *   2GB:   46340k
2172	 *   4GB:   65536k
2173	 *   8GB:   92681k
2174	 *  16GB:  131072k
2175	 *
2176	 * This allows larger machines to have larger/more transfers.
2177	 * Limit the default to 256M
2178	 */
2179	nfs_congestion_kb = (16*int_sqrt(totalram_pages())) << (PAGE_SHIFT-10);
2180	if (nfs_congestion_kb > 256*1024)
2181		nfs_congestion_kb = 256*1024;
2182
2183	return 0;
2184
2185out_destroy_commit_cache:
2186	kmem_cache_destroy(nfs_cdata_cachep);
2187out_destroy_write_mempool:
2188	mempool_destroy(nfs_wdata_mempool);
2189out_destroy_write_cache:
2190	kmem_cache_destroy(nfs_wdata_cachep);
2191	return -ENOMEM;
2192}
2193
2194void nfs_destroy_writepagecache(void)
2195{
2196	mempool_destroy(nfs_commit_mempool);
2197	kmem_cache_destroy(nfs_cdata_cachep);
2198	mempool_destroy(nfs_wdata_mempool);
2199	kmem_cache_destroy(nfs_wdata_cachep);
2200}
2201
2202static const struct nfs_rw_ops nfs_rw_write_ops = {
2203	.rw_alloc_header	= nfs_writehdr_alloc,
2204	.rw_free_header		= nfs_writehdr_free,
2205	.rw_done		= nfs_writeback_done,
2206	.rw_result		= nfs_writeback_result,
2207	.rw_initiate		= nfs_initiate_write,
2208};