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