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);
 
 
 
  66
  67static struct kmem_cache *nfs_wdata_cachep;
  68static mempool_t *nfs_wdata_mempool;
  69static struct kmem_cache *nfs_cdata_cachep;
  70static mempool_t *nfs_commit_mempool;
  71
  72struct nfs_commit_data *nfs_commitdata_alloc(void)
  73{
  74	struct nfs_commit_data *p;
  75
  76	p = kmem_cache_zalloc(nfs_cdata_cachep, nfs_io_gfp_mask());
  77	if (!p) {
  78		p = mempool_alloc(nfs_commit_mempool, GFP_NOWAIT);
  79		if (!p)
  80			return NULL;
  81		memset(p, 0, sizeof(*p));
  82	}
  83	INIT_LIST_HEAD(&p->pages);
  84	return p;
  85}
  86EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
  87
  88void nfs_commit_free(struct nfs_commit_data *p)
  89{
  90	mempool_free(p, nfs_commit_mempool);
  91}
  92EXPORT_SYMBOL_GPL(nfs_commit_free);
  93
  94static struct nfs_pgio_header *nfs_writehdr_alloc(void)
  95{
  96	struct nfs_pgio_header *p;
  97
  98	p = kmem_cache_zalloc(nfs_wdata_cachep, nfs_io_gfp_mask());
  99	if (!p) {
 100		p = mempool_alloc(nfs_wdata_mempool, GFP_NOWAIT);
 101		if (!p)
 102			return NULL;
 103		memset(p, 0, sizeof(*p));
 104	}
 105	p->rw_mode = FMODE_WRITE;
 106	return p;
 107}
 108
 109static void nfs_writehdr_free(struct nfs_pgio_header *hdr)
 110{
 111	mempool_free(hdr, nfs_wdata_mempool);
 112}
 113
 114static struct nfs_io_completion *nfs_io_completion_alloc(gfp_t gfp_flags)
 115{
 116	return kmalloc(sizeof(struct nfs_io_completion), gfp_flags);
 117}
 118
 119static void nfs_io_completion_init(struct nfs_io_completion *ioc,
 120		void (*complete)(void *), void *data)
 121{
 122	ioc->complete = complete;
 123	ioc->data = data;
 124	kref_init(&ioc->refcount);
 125}
 126
 127static void nfs_io_completion_release(struct kref *kref)
 128{
 129	struct nfs_io_completion *ioc = container_of(kref,
 130			struct nfs_io_completion, refcount);
 131	ioc->complete(ioc->data);
 132	kfree(ioc);
 133}
 134
 135static void nfs_io_completion_get(struct nfs_io_completion *ioc)
 136{
 137	if (ioc != NULL)
 138		kref_get(&ioc->refcount);
 139}
 140
 141static void nfs_io_completion_put(struct nfs_io_completion *ioc)
 142{
 143	if (ioc != NULL)
 144		kref_put(&ioc->refcount, nfs_io_completion_release);
 145}
 146
 147static void
 148nfs_page_set_inode_ref(struct nfs_page *req, struct inode *inode)
 149{
 150	if (!test_and_set_bit(PG_INODE_REF, &req->wb_flags)) {
 151		kref_get(&req->wb_kref);
 152		atomic_long_inc(&NFS_I(inode)->nrequests);
 153	}
 154}
 155
 156static int
 157nfs_cancel_remove_inode(struct nfs_page *req, struct inode *inode)
 158{
 159	int ret;
 160
 161	if (!test_bit(PG_REMOVE, &req->wb_flags))
 162		return 0;
 163	ret = nfs_page_group_lock(req);
 164	if (ret)
 165		return ret;
 166	if (test_and_clear_bit(PG_REMOVE, &req->wb_flags))
 167		nfs_page_set_inode_ref(req, inode);
 168	nfs_page_group_unlock(req);
 169	return 0;
 170}
 171
 172/**
 173 * nfs_folio_find_head_request - find head request associated with a folio
 174 * @folio: pointer to folio
 
 
 
 
 
 
 
 175 *
 176 * must be called while holding the inode lock.
 177 *
 178 * returns matching head request with reference held, or NULL if not found.
 179 */
 180static struct nfs_page *nfs_folio_find_head_request(struct folio *folio)
 
 181{
 182	struct address_space *mapping = folio->mapping;
 183	struct nfs_page *req;
 184
 185	if (!folio_test_private(folio))
 186		return NULL;
 187	spin_lock(&mapping->i_private_lock);
 188	req = folio->private;
 189	if (req) {
 190		WARN_ON_ONCE(req->wb_head != req);
 191		kref_get(&req->wb_kref);
 192	}
 193	spin_unlock(&mapping->i_private_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 194	return req;
 195}
 196
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 197/* Adjust the file length if we're writing beyond the end */
 198static void nfs_grow_file(struct folio *folio, unsigned int offset,
 199			  unsigned int count)
 200{
 201	struct inode *inode = folio->mapping->host;
 202	loff_t end, i_size;
 203	pgoff_t end_index;
 204
 205	spin_lock(&inode->i_lock);
 206	i_size = i_size_read(inode);
 207	end_index = ((i_size - 1) >> folio_shift(folio)) << folio_order(folio);
 208	if (i_size > 0 && folio->index < end_index)
 209		goto out;
 210	end = folio_pos(folio) + (loff_t)offset + (loff_t)count;
 211	if (i_size >= end)
 212		goto out;
 213	trace_nfs_size_grow(inode, end);
 214	i_size_write(inode, end);
 215	NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;
 216	nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 217out:
 218	/* Atomically update timestamps if they are delegated to us. */
 219	nfs_update_delegated_mtime_locked(inode);
 220	spin_unlock(&inode->i_lock);
 221	nfs_fscache_invalidate(inode, 0);
 222}
 223
 224/* A writeback failed: mark the page as bad, and invalidate the page cache */
 225static void nfs_set_pageerror(struct address_space *mapping)
 226{
 227	struct inode *inode = mapping->host;
 228
 229	nfs_zap_mapping(mapping->host, mapping);
 230	/* Force file size revalidation */
 231	spin_lock(&inode->i_lock);
 232	nfs_set_cache_invalid(inode, NFS_INO_REVAL_FORCED |
 233					     NFS_INO_INVALID_CHANGE |
 234					     NFS_INO_INVALID_SIZE);
 235	spin_unlock(&inode->i_lock);
 236}
 237
 238static void nfs_mapping_set_error(struct folio *folio, int error)
 239{
 240	struct address_space *mapping = folio->mapping;
 241
 
 242	filemap_set_wb_err(mapping, error);
 243	if (mapping->host)
 244		errseq_set(&mapping->host->i_sb->s_wb_err,
 245			   error == -ENOSPC ? -ENOSPC : -EIO);
 246	nfs_set_pageerror(mapping);
 247}
 248
 249/*
 250 * nfs_page_group_search_locked
 251 * @head - head request of page group
 252 * @page_offset - offset into page
 253 *
 254 * Search page group with head @head to find a request that contains the
 255 * page offset @page_offset.
 256 *
 257 * Returns a pointer to the first matching nfs request, or NULL if no
 258 * match is found.
 259 *
 260 * Must be called with the page group lock held
 261 */
 262static struct nfs_page *
 263nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset)
 264{
 265	struct nfs_page *req;
 266
 267	req = head;
 268	do {
 269		if (page_offset >= req->wb_pgbase &&
 270		    page_offset < (req->wb_pgbase + req->wb_bytes))
 271			return req;
 272
 273		req = req->wb_this_page;
 274	} while (req != head);
 275
 276	return NULL;
 277}
 278
 279/*
 280 * nfs_page_group_covers_page
 281 * @head - head request of page group
 282 *
 283 * Return true if the page group with head @head covers the whole page,
 284 * returns false otherwise
 285 */
 286static bool nfs_page_group_covers_page(struct nfs_page *req)
 287{
 288	unsigned int len = nfs_folio_length(nfs_page_to_folio(req));
 289	struct nfs_page *tmp;
 290	unsigned int pos = 0;
 
 291
 292	nfs_page_group_lock(req);
 293
 294	for (;;) {
 295		tmp = nfs_page_group_search_locked(req->wb_head, pos);
 296		if (!tmp)
 297			break;
 298		pos = tmp->wb_pgbase + tmp->wb_bytes;
 299	}
 300
 301	nfs_page_group_unlock(req);
 302	return pos >= len;
 303}
 304
 305/* We can set the PG_uptodate flag if we see that a write request
 306 * covers the full page.
 307 */
 308static void nfs_mark_uptodate(struct nfs_page *req)
 309{
 310	struct folio *folio = nfs_page_to_folio(req);
 311
 312	if (folio_test_uptodate(folio))
 313		return;
 314	if (!nfs_page_group_covers_page(req))
 315		return;
 316	folio_mark_uptodate(folio);
 317}
 318
 319static int wb_priority(struct writeback_control *wbc)
 320{
 321	int ret = 0;
 322
 323	if (wbc->sync_mode == WB_SYNC_ALL)
 324		ret = FLUSH_COND_STABLE;
 325	return ret;
 326}
 327
 328/*
 329 * NFS congestion control
 330 */
 331
 332int nfs_congestion_kb;
 333
 334#define NFS_CONGESTION_ON_THRESH 	(nfs_congestion_kb >> (PAGE_SHIFT-10))
 335#define NFS_CONGESTION_OFF_THRESH	\
 336	(NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 337
 338static void nfs_folio_set_writeback(struct folio *folio)
 339{
 340	struct nfs_server *nfss = NFS_SERVER(folio->mapping->host);
 
 
 
 
 341
 342	folio_start_writeback(folio);
 343	if (atomic_long_inc_return(&nfss->writeback) > NFS_CONGESTION_ON_THRESH)
 344		nfss->write_congested = 1;
 345}
 346
 347static void nfs_folio_end_writeback(struct folio *folio)
 348{
 349	struct nfs_server *nfss = NFS_SERVER(folio->mapping->host);
 
 
 350
 351	folio_end_writeback(folio);
 352	if (atomic_long_dec_return(&nfss->writeback) <
 353	    NFS_CONGESTION_OFF_THRESH) {
 354		nfss->write_congested = 0;
 355		wake_up_all(&nfss->write_congestion_wait);
 356	}
 357}
 358
 359static void nfs_page_end_writeback(struct nfs_page *req)
 360{
 361	if (nfs_page_group_sync_on_bit(req, PG_WB_END)) {
 362		nfs_unlock_request(req);
 363		nfs_folio_end_writeback(nfs_page_to_folio(req));
 364	} else
 365		nfs_unlock_request(req);
 366}
 367
 368/*
 369 * nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests
 370 *
 371 * @destroy_list - request list (using wb_this_page) terminated by @old_head
 372 * @old_head - the old head of the list
 373 *
 374 * All subrequests must be locked and removed from all lists, so at this point
 375 * they are only "active" in this function, and possibly in nfs_wait_on_request
 376 * with a reference held by some other context.
 377 */
 378static void
 379nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
 380				 struct nfs_page *old_head,
 381				 struct inode *inode)
 382{
 383	while (destroy_list) {
 384		struct nfs_page *subreq = destroy_list;
 385
 386		destroy_list = (subreq->wb_this_page == old_head) ?
 387				   NULL : subreq->wb_this_page;
 388
 389		/* Note: lock subreq in order to change subreq->wb_head */
 390		nfs_page_set_headlock(subreq);
 391		WARN_ON_ONCE(old_head != subreq->wb_head);
 392
 393		/* make sure old group is not used */
 394		subreq->wb_this_page = subreq;
 395		subreq->wb_head = subreq;
 396
 397		clear_bit(PG_REMOVE, &subreq->wb_flags);
 398
 399		/* Note: races with nfs_page_group_destroy() */
 400		if (!kref_read(&subreq->wb_kref)) {
 401			/* Check if we raced with nfs_page_group_destroy() */
 402			if (test_and_clear_bit(PG_TEARDOWN, &subreq->wb_flags)) {
 403				nfs_page_clear_headlock(subreq);
 404				nfs_free_request(subreq);
 405			} else
 406				nfs_page_clear_headlock(subreq);
 407			continue;
 408		}
 409		nfs_page_clear_headlock(subreq);
 410
 411		nfs_release_request(old_head);
 412
 413		if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) {
 414			nfs_release_request(subreq);
 415			atomic_long_dec(&NFS_I(inode)->nrequests);
 416		}
 417
 418		/* subreq is now totally disconnected from page group or any
 419		 * write / commit lists. last chance to wake any waiters */
 420		nfs_unlock_and_release_request(subreq);
 421	}
 422}
 423
 424/*
 425 * nfs_join_page_group - destroy subrequests of the head req
 426 * @head: the page used to lookup the "page group" of nfs_page structures
 427 * @inode: Inode to which the request belongs.
 428 *
 429 * This function joins all sub requests to the head request by first
 430 * locking all requests in the group, cancelling any pending operations
 431 * and finally updating the head request to cover the whole range covered by
 432 * the (former) group.  All subrequests are removed from any write or commit
 433 * lists, unlinked from the group and destroyed.
 434 */
 435void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo,
 436			 struct inode *inode)
 437{
 438	struct nfs_page *subreq;
 439	struct nfs_page *destroy_list = NULL;
 440	unsigned int pgbase, off, bytes;
 441
 442	pgbase = head->wb_pgbase;
 443	bytes = head->wb_bytes;
 444	off = head->wb_offset;
 445	for (subreq = head->wb_this_page; subreq != head;
 446			subreq = subreq->wb_this_page) {
 447		/* Subrequests should always form a contiguous range */
 448		if (pgbase > subreq->wb_pgbase) {
 449			off -= pgbase - subreq->wb_pgbase;
 450			bytes += pgbase - subreq->wb_pgbase;
 451			pgbase = subreq->wb_pgbase;
 452		}
 453		bytes = max(subreq->wb_pgbase + subreq->wb_bytes
 454				- pgbase, bytes);
 455	}
 456
 457	/* Set the head request's range to cover the former page group */
 458	head->wb_pgbase = pgbase;
 459	head->wb_bytes = bytes;
 460	head->wb_offset = off;
 461
 462	/* Now that all requests are locked, make sure they aren't on any list.
 463	 * Commit list removal accounting is done after locks are dropped */
 464	subreq = head;
 465	do {
 466		nfs_clear_request_commit(cinfo, subreq);
 467		subreq = subreq->wb_this_page;
 468	} while (subreq != head);
 469
 470	/* unlink subrequests from head, destroy them later */
 471	if (head->wb_this_page != head) {
 472		/* destroy list will be terminated by head */
 473		destroy_list = head->wb_this_page;
 474		head->wb_this_page = head;
 475	}
 476
 477	nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
 478}
 479
 480/**
 481 * nfs_wait_on_request - Wait for a request to complete.
 482 * @req: request to wait upon.
 483 *
 484 * Interruptible by fatal signals only.
 485 * The user is responsible for holding a count on the request.
 486 */
 487static int nfs_wait_on_request(struct nfs_page *req)
 488{
 489	if (!test_bit(PG_BUSY, &req->wb_flags))
 490		return 0;
 491	set_bit(PG_CONTENDED2, &req->wb_flags);
 492	smp_mb__after_atomic();
 493	return wait_on_bit_io(&req->wb_flags, PG_BUSY,
 494			      TASK_UNINTERRUPTIBLE);
 495}
 496
 497/*
 498 * nfs_unroll_locks -  unlock all newly locked reqs and wait on @req
 499 * @head: head request of page group, must be holding head lock
 500 * @req: request that couldn't lock and needs to wait on the req bit lock
 501 *
 502 * This is a helper function for nfs_lock_and_join_requests
 503 * returns 0 on success, < 0 on error.
 504 */
 505static void
 506nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req)
 507{
 508	struct nfs_page *tmp;
 509
 510	/* relinquish all the locks successfully grabbed this run */
 511	for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {
 512		if (!kref_read(&tmp->wb_kref))
 513			continue;
 514		nfs_unlock_and_release_request(tmp);
 515	}
 516}
 517
 518/*
 519 * nfs_page_group_lock_subreq -  try to lock a subrequest
 520 * @head: head request of page group
 521 * @subreq: request to lock
 522 *
 523 * This is a helper function for nfs_lock_and_join_requests which
 524 * must be called with the head request and page group both locked.
 525 * On error, it returns with the page group unlocked.
 526 */
 527static int
 528nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq)
 529{
 530	int ret;
 531
 532	if (!kref_get_unless_zero(&subreq->wb_kref))
 533		return 0;
 534	while (!nfs_lock_request(subreq)) {
 535		nfs_page_group_unlock(head);
 536		ret = nfs_wait_on_request(subreq);
 537		if (!ret)
 538			ret = nfs_page_group_lock(head);
 539		if (ret < 0) {
 540			nfs_unroll_locks(head, subreq);
 541			nfs_release_request(subreq);
 542			return ret;
 543		}
 544	}
 545	return 0;
 546}
 547
 548/*
 549 * nfs_lock_and_join_requests - join all subreqs to the head req
 550 * @folio: the folio used to lookup the "page group" of nfs_page structures
 551 *
 552 * This function joins all sub requests to the head request by first
 553 * locking all requests in the group, cancelling any pending operations
 554 * and finally updating the head request to cover the whole range covered by
 555 * the (former) group.  All subrequests are removed from any write or commit
 556 * lists, unlinked from the group and destroyed.
 557 *
 558 * Returns a locked, referenced pointer to the head request - which after
 559 * this call is guaranteed to be the only request associated with the page.
 560 * Returns NULL if no requests are found for @folio, or a ERR_PTR if an
 561 * error was encountered.
 562 */
 563static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio)
 
 564{
 565	struct inode *inode = folio->mapping->host;
 566	struct nfs_page *head, *subreq;
 567	struct nfs_commit_info cinfo;
 568	int ret;
 569
 570	/*
 571	 * A reference is taken only on the head request which acts as a
 572	 * reference to the whole page group - the group will not be destroyed
 573	 * until the head reference is released.
 574	 */
 575retry:
 576	head = nfs_folio_find_head_request(folio);
 577	if (!head)
 578		return NULL;
 579
 580	while (!nfs_lock_request(head)) {
 581		ret = nfs_wait_on_request(head);
 582		if (ret < 0)
 583			return ERR_PTR(ret);
 584	}
 585
 586	/* Ensure that nobody removed the request before we locked it */
 587	if (head != folio->private) {
 588		nfs_unlock_and_release_request(head);
 589		goto retry;
 590	}
 591
 592	ret = nfs_cancel_remove_inode(head, inode);
 593	if (ret < 0)
 594		goto out_unlock;
 595
 596	ret = nfs_page_group_lock(head);
 597	if (ret < 0)
 598		goto out_unlock;
 599
 600	/* lock each request in the page group */
 601	for (subreq = head->wb_this_page;
 602	     subreq != head;
 603	     subreq = subreq->wb_this_page) {
 604		ret = nfs_page_group_lock_subreq(head, subreq);
 605		if (ret < 0)
 606			goto out_unlock;
 607	}
 608
 609	nfs_page_group_unlock(head);
 610
 611	nfs_init_cinfo_from_inode(&cinfo, inode);
 612	nfs_join_page_group(head, &cinfo, inode);
 613	return head;
 614
 615out_unlock:
 616	nfs_unlock_and_release_request(head);
 617	return ERR_PTR(ret);
 618}
 619
 620static void nfs_write_error(struct nfs_page *req, int error)
 621{
 622	trace_nfs_write_error(nfs_page_to_inode(req), req, error);
 623	nfs_mapping_set_error(nfs_page_to_folio(req), error);
 
 624	nfs_inode_remove_request(req);
 625	nfs_page_end_writeback(req);
 626	nfs_release_request(req);
 627}
 628
 629/*
 630 * Find an associated nfs write request, and prepare to flush it out
 631 * May return an error if the user signalled nfs_wait_on_request().
 632 */
 633static int nfs_page_async_flush(struct folio *folio,
 634				struct writeback_control *wbc,
 635				struct nfs_pageio_descriptor *pgio)
 636{
 637	struct nfs_page *req;
 638	int ret = 0;
 639
 640	req = nfs_lock_and_join_requests(folio);
 641	if (!req)
 642		goto out;
 643	ret = PTR_ERR(req);
 644	if (IS_ERR(req))
 645		goto out;
 646
 647	nfs_folio_set_writeback(folio);
 648	WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
 649
 650	/* If there is a fatal error that covers this write, just exit */
 651	ret = pgio->pg_error;
 652	if (nfs_error_is_fatal_on_server(ret))
 653		goto out_launder;
 654
 655	ret = 0;
 656	if (!nfs_pageio_add_request(pgio, req)) {
 657		ret = pgio->pg_error;
 658		/*
 659		 * Remove the problematic req upon fatal errors on the server
 660		 */
 661		if (nfs_error_is_fatal_on_server(ret))
 662			goto out_launder;
 663		if (wbc->sync_mode == WB_SYNC_NONE)
 664			ret = AOP_WRITEPAGE_ACTIVATE;
 665		folio_redirty_for_writepage(wbc, folio);
 666		nfs_redirty_request(req);
 667		pgio->pg_error = 0;
 668	} else
 669		nfs_add_stats(folio->mapping->host,
 670			      NFSIOS_WRITEPAGES, 1);
 671out:
 672	return ret;
 673out_launder:
 674	nfs_write_error(req, ret);
 675	return 0;
 676}
 677
 678static int nfs_do_writepage(struct folio *folio, struct writeback_control *wbc,
 679			    struct nfs_pageio_descriptor *pgio)
 680{
 681	nfs_pageio_cond_complete(pgio, folio->index);
 682	return nfs_page_async_flush(folio, wbc, pgio);
 683}
 684
 685/*
 686 * Write an mmapped page to the server.
 687 */
 688static int nfs_writepage_locked(struct folio *folio,
 689				struct writeback_control *wbc)
 690{
 691	struct nfs_pageio_descriptor pgio;
 692	struct inode *inode = folio->mapping->host;
 693	int err;
 694
 
 
 
 
 695	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 696	nfs_pageio_init_write(&pgio, inode, 0, false,
 697			      &nfs_async_write_completion_ops);
 698	err = nfs_do_writepage(folio, wbc, &pgio);
 699	pgio.pg_error = 0;
 700	nfs_pageio_complete(&pgio);
 701	return err;
 702}
 703
 704static int nfs_writepages_callback(struct folio *folio,
 705				   struct writeback_control *wbc, void *data)
 706{
 707	int ret;
 708
 709	ret = nfs_do_writepage(folio, wbc, data);
 710	if (ret != AOP_WRITEPAGE_ACTIVATE)
 711		folio_unlock(folio);
 
 
 
 
 
 
 
 
 
 
 712	return ret;
 713}
 714
 715static void nfs_io_completion_commit(void *inode)
 716{
 717	nfs_commit_inode(inode, 0);
 718}
 719
 720int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 721{
 722	struct inode *inode = mapping->host;
 723	struct nfs_pageio_descriptor pgio;
 724	struct nfs_io_completion *ioc = NULL;
 725	unsigned int mntflags = NFS_SERVER(inode)->flags;
 726	struct nfs_server *nfss = NFS_SERVER(inode);
 727	int priority = 0;
 728	int err;
 729
 730	/* Wait with writeback until write congestion eases */
 731	if (wbc->sync_mode == WB_SYNC_NONE && nfss->write_congested) {
 732		err = wait_event_killable(nfss->write_congestion_wait,
 733					  nfss->write_congested == 0);
 734		if (err)
 735			return err;
 736	}
 737
 738	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 739
 740	if (!(mntflags & NFS_MOUNT_WRITE_EAGER) || wbc->for_kupdate ||
 741	    wbc->for_background || wbc->for_sync || wbc->for_reclaim) {
 742		ioc = nfs_io_completion_alloc(GFP_KERNEL);
 743		if (ioc)
 744			nfs_io_completion_init(ioc, nfs_io_completion_commit,
 745					       inode);
 746		priority = wb_priority(wbc);
 747	}
 748
 749	do {
 750		nfs_pageio_init_write(&pgio, inode, priority, false,
 751				      &nfs_async_write_completion_ops);
 752		pgio.pg_io_completion = ioc;
 753		err = write_cache_pages(mapping, wbc, nfs_writepages_callback,
 754					&pgio);
 755		pgio.pg_error = 0;
 756		nfs_pageio_complete(&pgio);
 757		if (err == -EAGAIN && mntflags & NFS_MOUNT_SOFTERR)
 758			break;
 759	} while (err < 0 && !nfs_error_is_fatal(err));
 760	nfs_io_completion_put(ioc);
 761
 762	if (err < 0)
 763		goto out_err;
 764	return 0;
 765out_err:
 766	return err;
 767}
 768
 769/*
 770 * Insert a write request into an inode
 771 */
 772static void nfs_inode_add_request(struct nfs_page *req)
 773{
 774	struct folio *folio = nfs_page_to_folio(req);
 775	struct address_space *mapping = folio->mapping;
 776	struct nfs_inode *nfsi = NFS_I(mapping->host);
 777
 778	WARN_ON_ONCE(req->wb_this_page != req);
 779
 780	/* Lock the request! */
 781	nfs_lock_request(req);
 782	spin_lock(&mapping->i_private_lock);
 783	set_bit(PG_MAPPED, &req->wb_flags);
 784	folio_set_private(folio);
 785	folio->private = req;
 786	spin_unlock(&mapping->i_private_lock);
 
 
 
 
 
 
 
 787	atomic_long_inc(&nfsi->nrequests);
 788	/* this a head request for a page group - mark it as having an
 789	 * extra reference so sub groups can follow suit.
 790	 * This flag also informs pgio layer when to bump nrequests when
 791	 * adding subrequests. */
 792	WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
 793	kref_get(&req->wb_kref);
 794}
 795
 796/*
 797 * Remove a write request from an inode
 798 */
 799static void nfs_inode_remove_request(struct nfs_page *req)
 800{
 801	struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req));
 
 
 
 802
 803	if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
 804		struct folio *folio = nfs_page_to_folio(req->wb_head);
 805		struct address_space *mapping = folio->mapping;
 806
 807		spin_lock(&mapping->i_private_lock);
 808		if (likely(folio)) {
 809			folio->private = NULL;
 810			folio_clear_private(folio);
 811			clear_bit(PG_MAPPED, &req->wb_head->wb_flags);
 812		}
 813		spin_unlock(&mapping->i_private_lock);
 814	}
 815
 816	if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) {
 817		atomic_long_dec(&nfsi->nrequests);
 818		nfs_release_request(req);
 
 819	}
 820}
 821
 822static void nfs_mark_request_dirty(struct nfs_page *req)
 
 823{
 824	struct folio *folio = nfs_page_to_folio(req);
 825	if (folio)
 826		filemap_dirty_folio(folio_mapping(folio), folio);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 827}
 828
 829/**
 830 * nfs_request_add_commit_list_locked - add request to a commit list
 831 * @req: pointer to a struct nfs_page
 832 * @dst: commit list head
 833 * @cinfo: holds list lock and accounting info
 834 *
 835 * This sets the PG_CLEAN bit, updates the cinfo count of
 836 * number of outstanding requests requiring a commit as well as
 837 * the MM page stats.
 838 *
 839 * The caller must hold NFS_I(cinfo->inode)->commit_mutex, and the
 840 * nfs_page lock.
 841 */
 842void
 843nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
 844			    struct nfs_commit_info *cinfo)
 845{
 846	set_bit(PG_CLEAN, &req->wb_flags);
 847	nfs_list_add_request(req, dst);
 848	atomic_long_inc(&cinfo->mds->ncommit);
 849}
 850EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
 851
 852/**
 853 * nfs_request_add_commit_list - add request to a commit list
 854 * @req: pointer to a struct nfs_page
 855 * @cinfo: holds list lock and accounting info
 856 *
 857 * This sets the PG_CLEAN bit, updates the cinfo count of
 858 * number of outstanding requests requiring a commit as well as
 859 * the MM page stats.
 860 *
 861 * The caller must _not_ hold the cinfo->lock, but must be
 862 * holding the nfs_page lock.
 863 */
 864void
 865nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
 866{
 867	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
 868	nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
 869	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
 870	nfs_folio_mark_unstable(nfs_page_to_folio(req), cinfo);
 
 871}
 872EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
 873
 874/**
 875 * nfs_request_remove_commit_list - Remove request from a commit list
 876 * @req: pointer to a nfs_page
 877 * @cinfo: holds list lock and accounting info
 878 *
 879 * This clears the PG_CLEAN bit, and updates the cinfo's count of
 880 * number of outstanding requests requiring a commit
 881 * It does not update the MM page stats.
 882 *
 883 * The caller _must_ hold the cinfo->lock and the nfs_page lock.
 884 */
 885void
 886nfs_request_remove_commit_list(struct nfs_page *req,
 887			       struct nfs_commit_info *cinfo)
 888{
 889	if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
 890		return;
 891	nfs_list_remove_request(req);
 892	atomic_long_dec(&cinfo->mds->ncommit);
 893}
 894EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
 895
 896static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
 897				      struct inode *inode)
 898{
 899	cinfo->inode = inode;
 900	cinfo->mds = &NFS_I(inode)->commit_info;
 901	cinfo->ds = pnfs_get_ds_info(inode);
 902	cinfo->dreq = NULL;
 903	cinfo->completion_ops = &nfs_commit_completion_ops;
 904}
 905
 906void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 907		    struct inode *inode,
 908		    struct nfs_direct_req *dreq)
 909{
 910	if (dreq)
 911		nfs_init_cinfo_from_dreq(cinfo, dreq);
 912	else
 913		nfs_init_cinfo_from_inode(cinfo, inode);
 914}
 915EXPORT_SYMBOL_GPL(nfs_init_cinfo);
 916
 917/*
 918 * Add a request to the inode's commit list.
 919 */
 920void
 921nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
 922			struct nfs_commit_info *cinfo, u32 ds_commit_idx)
 923{
 924	if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx))
 925		return;
 926	nfs_request_add_commit_list(req, cinfo);
 927}
 928
 929static void nfs_folio_clear_commit(struct folio *folio)
 
 930{
 931	if (folio) {
 932		long nr = folio_nr_pages(folio);
 933
 934		node_stat_mod_folio(folio, NR_WRITEBACK, -nr);
 935		wb_stat_mod(&inode_to_bdi(folio->mapping->host)->wb,
 936			    WB_WRITEBACK, -nr);
 937	}
 938}
 939
 940/* Called holding the request lock on @req */
 941static void nfs_clear_request_commit(struct nfs_commit_info *cinfo,
 942				     struct nfs_page *req)
 943{
 944	if (test_bit(PG_CLEAN, &req->wb_flags)) {
 945		struct nfs_open_context *ctx = nfs_req_openctx(req);
 946		struct inode *inode = d_inode(ctx->dentry);
 
 947
 
 948		mutex_lock(&NFS_I(inode)->commit_mutex);
 949		if (!pnfs_clear_request_commit(req, cinfo)) {
 950			nfs_request_remove_commit_list(req, cinfo);
 951		}
 952		mutex_unlock(&NFS_I(inode)->commit_mutex);
 953		nfs_folio_clear_commit(nfs_page_to_folio(req));
 954	}
 955}
 956
 957int nfs_write_need_commit(struct nfs_pgio_header *hdr)
 958{
 959	if (hdr->verf.committed == NFS_DATA_SYNC)
 960		return hdr->lseg == NULL;
 961	return hdr->verf.committed != NFS_FILE_SYNC;
 962}
 963
 964static void nfs_async_write_init(struct nfs_pgio_header *hdr)
 965{
 966	nfs_io_completion_get(hdr->io_completion);
 967}
 968
 969static void nfs_write_completion(struct nfs_pgio_header *hdr)
 970{
 971	struct nfs_commit_info cinfo;
 972	unsigned long bytes = 0;
 973
 974	if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
 975		goto out;
 976	nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
 977	while (!list_empty(&hdr->pages)) {
 978		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
 979
 980		bytes += req->wb_bytes;
 981		nfs_list_remove_request(req);
 982		if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
 983		    (hdr->good_bytes < bytes)) {
 984			trace_nfs_comp_error(hdr->inode, req, hdr->error);
 985			nfs_mapping_set_error(nfs_page_to_folio(req),
 986					      hdr->error);
 987			goto remove_req;
 988		}
 989		if (nfs_write_need_commit(hdr)) {
 990			/* Reset wb_nio, since the write was successful. */
 991			req->wb_nio = 0;
 992			memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
 993			nfs_mark_request_commit(req, hdr->lseg, &cinfo,
 994				hdr->pgio_mirror_idx);
 995			goto next;
 996		}
 997remove_req:
 998		nfs_inode_remove_request(req);
 999next:
1000		nfs_page_end_writeback(req);
1001		nfs_release_request(req);
1002	}
1003out:
1004	nfs_io_completion_put(hdr->io_completion);
1005	hdr->release(hdr);
1006}
1007
1008unsigned long
1009nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
1010{
1011	return atomic_long_read(&cinfo->mds->ncommit);
1012}
1013
1014/* NFS_I(cinfo->inode)->commit_mutex held by caller */
1015int
1016nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
1017		     struct nfs_commit_info *cinfo, int max)
1018{
1019	struct nfs_page *req, *tmp;
1020	int ret = 0;
1021
1022	list_for_each_entry_safe(req, tmp, src, wb_list) {
1023		kref_get(&req->wb_kref);
1024		if (!nfs_lock_request(req)) {
1025			nfs_release_request(req);
1026			continue;
1027		}
1028		nfs_request_remove_commit_list(req, cinfo);
1029		clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
1030		nfs_list_add_request(req, dst);
1031		ret++;
1032		if ((ret == max) && !cinfo->dreq)
1033			break;
1034		cond_resched();
1035	}
1036	return ret;
1037}
1038EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
1039
1040/*
1041 * nfs_scan_commit - Scan an inode for commit requests
1042 * @inode: NFS inode to scan
1043 * @dst: mds destination list
1044 * @cinfo: mds and ds lists of reqs ready to commit
1045 *
1046 * Moves requests from the inode's 'commit' request list.
1047 * The requests are *not* checked to ensure that they form a contiguous set.
1048 */
1049int
1050nfs_scan_commit(struct inode *inode, struct list_head *dst,
1051		struct nfs_commit_info *cinfo)
1052{
1053	int ret = 0;
1054
1055	if (!atomic_long_read(&cinfo->mds->ncommit))
1056		return 0;
1057	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
1058	if (atomic_long_read(&cinfo->mds->ncommit) > 0) {
1059		const int max = INT_MAX;
1060
1061		ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
1062					   cinfo, max);
1063		ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
1064	}
1065	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
1066	return ret;
1067}
1068
1069/*
1070 * Search for an existing write request, and attempt to update
1071 * it to reflect a new dirty region on a given page.
1072 *
1073 * If the attempt fails, then the existing request is flushed out
1074 * to disk.
1075 */
1076static struct nfs_page *nfs_try_to_update_request(struct folio *folio,
1077						  unsigned int offset,
1078						  unsigned int bytes)
 
1079{
1080	struct nfs_page *req;
1081	unsigned int rqend;
1082	unsigned int end;
1083	int error;
1084
1085	end = offset + bytes;
1086
1087	req = nfs_lock_and_join_requests(folio);
1088	if (IS_ERR_OR_NULL(req))
1089		return req;
1090
1091	rqend = req->wb_offset + req->wb_bytes;
1092	/*
1093	 * Tell the caller to flush out the request if
1094	 * the offsets are non-contiguous.
1095	 * Note: nfs_flush_incompatible() will already
1096	 * have flushed out requests having wrong owners.
1097	 */
1098	if (offset > rqend || end < req->wb_offset)
1099		goto out_flushme;
1100
1101	/* Okay, the request matches. Update the region */
1102	if (offset < req->wb_offset) {
1103		req->wb_offset = offset;
1104		req->wb_pgbase = offset;
1105	}
1106	if (end > rqend)
1107		req->wb_bytes = end - req->wb_offset;
1108	else
1109		req->wb_bytes = rqend - req->wb_offset;
1110	req->wb_nio = 0;
1111	return req;
1112out_flushme:
1113	/*
1114	 * Note: we mark the request dirty here because
1115	 * nfs_lock_and_join_requests() cannot preserve
1116	 * commit flags, so we have to replay the write.
1117	 */
1118	nfs_mark_request_dirty(req);
1119	nfs_unlock_and_release_request(req);
1120	error = nfs_wb_folio(folio->mapping->host, folio);
1121	return (error < 0) ? ERR_PTR(error) : NULL;
1122}
1123
1124/*
1125 * Try to update an existing write request, or create one if there is none.
1126 *
1127 * Note: Should always be called with the Page Lock held to prevent races
1128 * if we have to add a new request. Also assumes that the caller has
1129 * already called nfs_flush_incompatible() if necessary.
1130 */
1131static struct nfs_page *nfs_setup_write_request(struct nfs_open_context *ctx,
1132						struct folio *folio,
1133						unsigned int offset,
1134						unsigned int bytes)
1135{
1136	struct nfs_page *req;
 
1137
1138	req = nfs_try_to_update_request(folio, offset, bytes);
1139	if (req != NULL)
1140		goto out;
1141	req = nfs_page_create_from_folio(ctx, folio, offset, bytes);
1142	if (IS_ERR(req))
1143		goto out;
1144	nfs_inode_add_request(req);
1145out:
1146	return req;
1147}
1148
1149static int nfs_writepage_setup(struct nfs_open_context *ctx,
1150			       struct folio *folio, unsigned int offset,
1151			       unsigned int count)
1152{
1153	struct nfs_page *req;
1154
1155	req = nfs_setup_write_request(ctx, folio, offset, count);
1156	if (IS_ERR(req))
1157		return PTR_ERR(req);
1158	/* Update file length */
1159	nfs_grow_file(folio, offset, count);
1160	nfs_mark_uptodate(req);
1161	nfs_mark_request_dirty(req);
1162	nfs_unlock_and_release_request(req);
1163	return 0;
1164}
1165
1166int nfs_flush_incompatible(struct file *file, struct folio *folio)
1167{
1168	struct nfs_open_context *ctx = nfs_file_open_context(file);
1169	struct nfs_lock_context *l_ctx;
1170	struct file_lock_context *flctx = locks_inode_context(file_inode(file));
1171	struct nfs_page	*req;
1172	int do_flush, status;
1173	/*
1174	 * Look for a request corresponding to this page. If there
1175	 * is one, and it belongs to another file, we flush it out
1176	 * before we try to copy anything into the page. Do this
1177	 * due to the lack of an ACCESS-type call in NFSv2.
1178	 * Also do the same if we find a request from an existing
1179	 * dropped page.
1180	 */
1181	do {
1182		req = nfs_folio_find_head_request(folio);
1183		if (req == NULL)
1184			return 0;
1185		l_ctx = req->wb_lock_context;
1186		do_flush = nfs_page_to_folio(req) != folio ||
1187			   !nfs_match_open_context(nfs_req_openctx(req), ctx);
1188		if (l_ctx && flctx &&
1189		    !(list_empty_careful(&flctx->flc_posix) &&
1190		      list_empty_careful(&flctx->flc_flock))) {
1191			do_flush |= l_ctx->lockowner != current->files;
1192		}
1193		nfs_release_request(req);
1194		if (!do_flush)
1195			return 0;
1196		status = nfs_wb_folio(folio->mapping->host, folio);
1197	} while (status == 0);
1198	return status;
1199}
1200
1201/*
1202 * Avoid buffered writes when a open context credential's key would
1203 * expire soon.
1204 *
1205 * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
1206 *
1207 * Return 0 and set a credential flag which triggers the inode to flush
1208 * and performs  NFS_FILE_SYNC writes if the key will expired within
1209 * RPC_KEY_EXPIRE_TIMEO.
1210 */
1211int
1212nfs_key_timeout_notify(struct file *filp, struct inode *inode)
1213{
1214	struct nfs_open_context *ctx = nfs_file_open_context(filp);
1215
1216	if (nfs_ctx_key_to_expire(ctx, inode) &&
1217	    !rcu_access_pointer(ctx->ll_cred))
1218		/* Already expired! */
1219		return -EACCES;
1220	return 0;
1221}
1222
1223/*
1224 * Test if the open context credential key is marked to expire soon.
1225 */
1226bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx, struct inode *inode)
1227{
1228	struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
1229	struct rpc_cred *cred, *new, *old = NULL;
1230	struct auth_cred acred = {
1231		.cred = ctx->cred,
1232	};
1233	bool ret = false;
1234
1235	rcu_read_lock();
1236	cred = rcu_dereference(ctx->ll_cred);
1237	if (cred && !(cred->cr_ops->crkey_timeout &&
1238		      cred->cr_ops->crkey_timeout(cred)))
1239		goto out;
1240	rcu_read_unlock();
1241
1242	new = auth->au_ops->lookup_cred(auth, &acred, 0);
1243	if (new == cred) {
1244		put_rpccred(new);
1245		return true;
1246	}
1247	if (IS_ERR_OR_NULL(new)) {
1248		new = NULL;
1249		ret = true;
1250	} else if (new->cr_ops->crkey_timeout &&
1251		   new->cr_ops->crkey_timeout(new))
1252		ret = true;
1253
1254	rcu_read_lock();
1255	old = rcu_dereference_protected(xchg(&ctx->ll_cred,
1256					     RCU_INITIALIZER(new)), 1);
1257out:
1258	rcu_read_unlock();
1259	put_rpccred(old);
1260	return ret;
1261}
1262
1263/*
1264 * If the page cache is marked as unsafe or invalid, then we can't rely on
1265 * the PageUptodate() flag. In this case, we will need to turn off
1266 * write optimisations that depend on the page contents being correct.
1267 */
1268static bool nfs_folio_write_uptodate(struct folio *folio, unsigned int pagelen)
 
1269{
1270	struct inode *inode = folio->mapping->host;
1271	struct nfs_inode *nfsi = NFS_I(inode);
1272
1273	if (nfs_have_delegated_attributes(inode))
1274		goto out;
1275	if (nfsi->cache_validity &
1276	    (NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_SIZE))
1277		return false;
1278	smp_rmb();
1279	if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags) && pagelen != 0)
1280		return false;
1281out:
1282	if (nfsi->cache_validity & NFS_INO_INVALID_DATA && pagelen != 0)
1283		return false;
1284	return folio_test_uptodate(folio) != 0;
1285}
1286
1287static bool
1288is_whole_file_wrlock(struct file_lock *fl)
1289{
1290	return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX &&
1291			lock_is_write(fl);
1292}
1293
1294/* If we know the page is up to date, and we're not using byte range locks (or
1295 * if we have the whole file locked for writing), it may be more efficient to
1296 * extend the write to cover the entire page in order to avoid fragmentation
1297 * inefficiencies.
1298 *
1299 * If the file is opened for synchronous writes then we can just skip the rest
1300 * of the checks.
1301 */
1302static int nfs_can_extend_write(struct file *file, struct folio *folio,
1303				unsigned int pagelen)
1304{
1305	struct inode *inode = file_inode(file);
1306	struct file_lock_context *flctx = locks_inode_context(inode);
1307	struct file_lock *fl;
1308	int ret;
1309	unsigned int mntflags = NFS_SERVER(inode)->flags;
1310
1311	if (mntflags & NFS_MOUNT_NO_ALIGNWRITE)
1312		return 0;
1313	if (file->f_flags & O_DSYNC)
1314		return 0;
1315	if (!nfs_folio_write_uptodate(folio, pagelen))
1316		return 0;
1317	if (nfs_have_write_delegation(inode))
1318		return 1;
1319	if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
1320		       list_empty_careful(&flctx->flc_posix)))
1321		return 1;
1322
1323	/* Check to see if there are whole file write locks */
1324	ret = 0;
1325	spin_lock(&flctx->flc_lock);
1326	if (!list_empty(&flctx->flc_posix)) {
1327		fl = list_first_entry(&flctx->flc_posix, struct file_lock,
1328					c.flc_list);
1329		if (is_whole_file_wrlock(fl))
1330			ret = 1;
1331	} else if (!list_empty(&flctx->flc_flock)) {
1332		fl = list_first_entry(&flctx->flc_flock, struct file_lock,
1333					c.flc_list);
1334		if (lock_is_write(fl))
1335			ret = 1;
1336	}
1337	spin_unlock(&flctx->flc_lock);
1338	return ret;
1339}
1340
1341/*
1342 * Update and possibly write a cached page of an NFS file.
1343 *
1344 * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
1345 * things with a page scheduled for an RPC call (e.g. invalidate it).
1346 */
1347int nfs_update_folio(struct file *file, struct folio *folio,
1348		     unsigned int offset, unsigned int count)
1349{
1350	struct nfs_open_context *ctx = nfs_file_open_context(file);
1351	struct address_space *mapping = folio->mapping;
1352	struct inode *inode = mapping->host;
1353	unsigned int pagelen = nfs_folio_length(folio);
1354	int		status = 0;
1355
1356	nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
1357
1358	dprintk("NFS:       nfs_update_folio(%pD2 %d@%lld)\n", file, count,
1359		(long long)(folio_pos(folio) + offset));
1360
1361	if (!count)
1362		goto out;
1363
1364	if (nfs_can_extend_write(file, folio, pagelen)) {
1365		unsigned int end = count + offset;
1366
1367		offset = round_down(offset, PAGE_SIZE);
1368		if (end < pagelen)
1369			end = min(round_up(end, PAGE_SIZE), pagelen);
1370		count = end - offset;
1371	}
1372
1373	status = nfs_writepage_setup(ctx, folio, offset, count);
1374	if (status < 0)
1375		nfs_set_pageerror(mapping);
1376out:
1377	dprintk("NFS:       nfs_update_folio returns %d (isize %lld)\n",
1378			status, (long long)i_size_read(inode));
1379	return status;
1380}
1381
1382static int flush_task_priority(int how)
1383{
1384	switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
1385		case FLUSH_HIGHPRI:
1386			return RPC_PRIORITY_HIGH;
1387		case FLUSH_LOWPRI:
1388			return RPC_PRIORITY_LOW;
1389	}
1390	return RPC_PRIORITY_NORMAL;
1391}
1392
1393static void nfs_initiate_write(struct nfs_pgio_header *hdr,
1394			       struct rpc_message *msg,
1395			       const struct nfs_rpc_ops *rpc_ops,
1396			       struct rpc_task_setup *task_setup_data, int how)
1397{
1398	int priority = flush_task_priority(how);
1399
1400	if (IS_SWAPFILE(hdr->inode))
1401		task_setup_data->flags |= RPC_TASK_SWAPPER;
1402	task_setup_data->priority = priority;
1403	rpc_ops->write_setup(hdr, msg, &task_setup_data->rpc_client);
1404	trace_nfs_initiate_write(hdr);
1405}
1406
1407/* If a nfs_flush_* function fails, it should remove reqs from @head and
1408 * call this on each, which will prepare them to be retried on next
1409 * writeback using standard nfs.
1410 */
1411static void nfs_redirty_request(struct nfs_page *req)
1412{
1413	struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req));
1414
1415	/* Bump the transmission count */
1416	req->wb_nio++;
1417	nfs_mark_request_dirty(req);
1418	atomic_long_inc(&nfsi->redirtied_pages);
1419	nfs_page_end_writeback(req);
1420	nfs_release_request(req);
1421}
1422
1423static void nfs_async_write_error(struct list_head *head, int error)
1424{
1425	struct nfs_page	*req;
1426
1427	while (!list_empty(head)) {
1428		req = nfs_list_entry(head->next);
1429		nfs_list_remove_request(req);
1430		if (nfs_error_is_fatal_on_server(error))
1431			nfs_write_error(req, error);
1432		else
1433			nfs_redirty_request(req);
1434	}
1435}
1436
1437static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)
1438{
1439	nfs_async_write_error(&hdr->pages, 0);
1440}
1441
1442static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
1443	.init_hdr = nfs_async_write_init,
1444	.error_cleanup = nfs_async_write_error,
1445	.completion = nfs_write_completion,
1446	.reschedule_io = nfs_async_write_reschedule_io,
1447};
1448
1449void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1450			       struct inode *inode, int ioflags, bool force_mds,
1451			       const struct nfs_pgio_completion_ops *compl_ops)
1452{
1453	struct nfs_server *server = NFS_SERVER(inode);
1454	const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
1455
1456#ifdef CONFIG_NFS_V4_1
1457	if (server->pnfs_curr_ld && !force_mds)
1458		pg_ops = server->pnfs_curr_ld->pg_write_ops;
1459#endif
1460	nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops,
1461			server->wsize, ioflags);
1462}
1463EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
1464
1465void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1466{
1467	struct nfs_pgio_mirror *mirror;
1468
1469	if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
1470		pgio->pg_ops->pg_cleanup(pgio);
1471
1472	pgio->pg_ops = &nfs_pgio_rw_ops;
1473
1474	nfs_pageio_stop_mirroring(pgio);
1475
1476	mirror = &pgio->pg_mirrors[0];
1477	mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1478}
1479EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1480
1481
1482void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1483{
1484	struct nfs_commit_data *data = calldata;
1485
1486	NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1487}
1488
1489static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
1490		struct nfs_fattr *fattr)
1491{
1492	struct nfs_pgio_args *argp = &hdr->args;
1493	struct nfs_pgio_res *resp = &hdr->res;
1494	u64 size = argp->offset + resp->count;
1495
1496	if (!(fattr->valid & NFS_ATTR_FATTR_SIZE))
1497		fattr->size = size;
1498	if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) {
1499		fattr->valid &= ~NFS_ATTR_FATTR_SIZE;
1500		return;
1501	}
1502	if (size != fattr->size)
1503		return;
1504	/* Set attribute barrier */
1505	nfs_fattr_set_barrier(fattr);
1506	/* ...and update size */
1507	fattr->valid |= NFS_ATTR_FATTR_SIZE;
1508}
1509
1510void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
1511{
1512	struct nfs_fattr *fattr = &hdr->fattr;
1513	struct inode *inode = hdr->inode;
1514
1515	if (nfs_have_delegated_mtime(inode)) {
1516		spin_lock(&inode->i_lock);
1517		nfs_set_cache_invalid(inode, NFS_INO_INVALID_BLOCKS);
1518		spin_unlock(&inode->i_lock);
1519		return;
1520	}
1521
1522	spin_lock(&inode->i_lock);
1523	nfs_writeback_check_extend(hdr, fattr);
1524	nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
1525	spin_unlock(&inode->i_lock);
1526}
1527EXPORT_SYMBOL_GPL(nfs_writeback_update_inode);
1528
1529/*
1530 * This function is called when the WRITE call is complete.
1531 */
1532static int nfs_writeback_done(struct rpc_task *task,
1533			      struct nfs_pgio_header *hdr,
1534			      struct inode *inode)
1535{
1536	int status;
1537
1538	/*
1539	 * ->write_done will attempt to use post-op attributes to detect
1540	 * conflicting writes by other clients.  A strict interpretation
1541	 * of close-to-open would allow us to continue caching even if
1542	 * another writer had changed the file, but some applications
1543	 * depend on tighter cache coherency when writing.
1544	 */
1545	status = NFS_PROTO(inode)->write_done(task, hdr);
1546	if (status != 0)
1547		return status;
1548
1549	nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count);
1550	trace_nfs_writeback_done(task, hdr);
1551
1552	if (task->tk_status >= 0) {
1553		enum nfs3_stable_how committed = hdr->res.verf->committed;
1554
1555		if (committed == NFS_UNSTABLE) {
1556			/*
1557			 * We have some uncommitted data on the server at
1558			 * this point, so ensure that we keep track of that
1559			 * fact irrespective of what later writes do.
1560			 */
1561			set_bit(NFS_IOHDR_UNSTABLE_WRITES, &hdr->flags);
1562		}
1563
1564		if (committed < hdr->args.stable) {
1565			/* We tried a write call, but the server did not
1566			 * commit data to stable storage even though we
1567			 * requested it.
1568			 * Note: There is a known bug in Tru64 < 5.0 in which
1569			 *	 the server reports NFS_DATA_SYNC, but performs
1570			 *	 NFS_FILE_SYNC. We therefore implement this checking
1571			 *	 as a dprintk() in order to avoid filling syslog.
1572			 */
1573			static unsigned long    complain;
1574
1575			/* Note this will print the MDS for a DS write */
1576			if (time_before(complain, jiffies)) {
1577				dprintk("NFS:       faulty NFS server %s:"
1578					" (committed = %d) != (stable = %d)\n",
1579					NFS_SERVER(inode)->nfs_client->cl_hostname,
1580					committed, hdr->args.stable);
1581				complain = jiffies + 300 * HZ;
1582			}
1583		}
1584	}
1585
1586	/* Deal with the suid/sgid bit corner case */
1587	if (nfs_should_remove_suid(inode)) {
1588		spin_lock(&inode->i_lock);
1589		nfs_set_cache_invalid(inode, NFS_INO_INVALID_MODE);
1590		spin_unlock(&inode->i_lock);
1591	}
1592	return 0;
1593}
1594
1595/*
1596 * This function is called when the WRITE call is complete.
1597 */
1598static void nfs_writeback_result(struct rpc_task *task,
1599				 struct nfs_pgio_header *hdr)
1600{
1601	struct nfs_pgio_args	*argp = &hdr->args;
1602	struct nfs_pgio_res	*resp = &hdr->res;
1603
1604	if (resp->count < argp->count) {
1605		static unsigned long    complain;
1606
1607		/* This a short write! */
1608		nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE);
1609
1610		/* Has the server at least made some progress? */
1611		if (resp->count == 0) {
1612			if (time_before(complain, jiffies)) {
1613				printk(KERN_WARNING
1614				       "NFS: Server wrote zero bytes, expected %u.\n",
1615				       argp->count);
1616				complain = jiffies + 300 * HZ;
1617			}
1618			nfs_set_pgio_error(hdr, -EIO, argp->offset);
1619			task->tk_status = -EIO;
1620			return;
1621		}
1622
1623		/* For non rpc-based layout drivers, retry-through-MDS */
1624		if (!task->tk_ops) {
1625			hdr->pnfs_error = -EAGAIN;
1626			return;
1627		}
1628
1629		/* Was this an NFSv2 write or an NFSv3 stable write? */
1630		if (resp->verf->committed != NFS_UNSTABLE) {
1631			/* Resend from where the server left off */
1632			hdr->mds_offset += resp->count;
1633			argp->offset += resp->count;
1634			argp->pgbase += resp->count;
1635			argp->count -= resp->count;
1636		} else {
1637			/* Resend as a stable write in order to avoid
1638			 * headaches in the case of a server crash.
1639			 */
1640			argp->stable = NFS_FILE_SYNC;
1641		}
1642		resp->count = 0;
1643		resp->verf->committed = 0;
1644		rpc_restart_call_prepare(task);
1645	}
1646}
1647
1648static int wait_on_commit(struct nfs_mds_commit_info *cinfo)
1649{
1650	return wait_var_event_killable(&cinfo->rpcs_out,
1651				       !atomic_read(&cinfo->rpcs_out));
1652}
1653
1654void nfs_commit_begin(struct nfs_mds_commit_info *cinfo)
1655{
1656	atomic_inc(&cinfo->rpcs_out);
1657}
1658
1659bool nfs_commit_end(struct nfs_mds_commit_info *cinfo)
1660{
1661	if (atomic_dec_and_test(&cinfo->rpcs_out)) {
1662		wake_up_var(&cinfo->rpcs_out);
1663		return true;
1664	}
1665	return false;
1666}
1667
1668void nfs_commitdata_release(struct nfs_commit_data *data)
1669{
1670	put_nfs_open_context(data->context);
1671	nfs_commit_free(data);
1672}
1673EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1674
1675int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
1676			const struct nfs_rpc_ops *nfs_ops,
1677			const struct rpc_call_ops *call_ops,
1678			int how, int flags,
1679			struct nfsd_file *localio)
1680{
1681	struct rpc_task *task;
1682	int priority = flush_task_priority(how);
1683	struct rpc_message msg = {
1684		.rpc_argp = &data->args,
1685		.rpc_resp = &data->res,
1686		.rpc_cred = data->cred,
1687	};
1688	struct rpc_task_setup task_setup_data = {
1689		.task = &data->task,
1690		.rpc_client = clnt,
1691		.rpc_message = &msg,
1692		.callback_ops = call_ops,
1693		.callback_data = data,
1694		.workqueue = nfsiod_workqueue,
1695		.flags = RPC_TASK_ASYNC | flags,
1696		.priority = priority,
1697	};
1698
1699	if (nfs_server_capable(data->inode, NFS_CAP_MOVEABLE))
1700		task_setup_data.flags |= RPC_TASK_MOVEABLE;
1701
1702	/* Set up the initial task struct.  */
1703	nfs_ops->commit_setup(data, &msg, &task_setup_data.rpc_client);
1704	trace_nfs_initiate_commit(data);
1705
1706	dprintk("NFS: initiated commit call\n");
1707
1708	if (localio)
1709		return nfs_local_commit(localio, data, call_ops, how);
1710
1711	task = rpc_run_task(&task_setup_data);
1712	if (IS_ERR(task))
1713		return PTR_ERR(task);
1714	if (how & FLUSH_SYNC)
1715		rpc_wait_for_completion_task(task);
1716	rpc_put_task(task);
1717	return 0;
1718}
1719EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1720
1721static loff_t nfs_get_lwb(struct list_head *head)
1722{
1723	loff_t lwb = 0;
1724	struct nfs_page *req;
1725
1726	list_for_each_entry(req, head, wb_list)
1727		if (lwb < (req_offset(req) + req->wb_bytes))
1728			lwb = req_offset(req) + req->wb_bytes;
1729
1730	return lwb;
1731}
1732
1733/*
1734 * Set up the argument/result storage required for the RPC call.
1735 */
1736void nfs_init_commit(struct nfs_commit_data *data,
1737		     struct list_head *head,
1738		     struct pnfs_layout_segment *lseg,
1739		     struct nfs_commit_info *cinfo)
1740{
1741	struct nfs_page *first;
1742	struct nfs_open_context *ctx;
1743	struct inode *inode;
1744
1745	/* Set up the RPC argument and reply structs
1746	 * NB: take care not to mess about with data->commit et al. */
1747
1748	if (head)
1749		list_splice_init(head, &data->pages);
1750
1751	first = nfs_list_entry(data->pages.next);
1752	ctx = nfs_req_openctx(first);
1753	inode = d_inode(ctx->dentry);
1754
1755	data->inode	  = inode;
1756	data->cred	  = ctx->cred;
1757	data->lseg	  = lseg; /* reference transferred */
1758	/* only set lwb for pnfs commit */
1759	if (lseg)
1760		data->lwb = nfs_get_lwb(&data->pages);
1761	data->mds_ops     = &nfs_commit_ops;
1762	data->completion_ops = cinfo->completion_ops;
1763	data->dreq	  = cinfo->dreq;
1764
1765	data->args.fh     = NFS_FH(data->inode);
1766	/* Note: we always request a commit of the entire inode */
1767	data->args.offset = 0;
1768	data->args.count  = 0;
1769	data->context     = get_nfs_open_context(ctx);
1770	data->res.fattr   = &data->fattr;
1771	data->res.verf    = &data->verf;
1772	nfs_fattr_init(&data->fattr);
1773	nfs_commit_begin(cinfo->mds);
1774}
1775EXPORT_SYMBOL_GPL(nfs_init_commit);
1776
1777void nfs_retry_commit(struct list_head *page_list,
1778		      struct pnfs_layout_segment *lseg,
1779		      struct nfs_commit_info *cinfo,
1780		      u32 ds_commit_idx)
1781{
1782	struct nfs_page *req;
1783
1784	while (!list_empty(page_list)) {
1785		req = nfs_list_entry(page_list->next);
1786		nfs_list_remove_request(req);
1787		nfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx);
1788		nfs_folio_clear_commit(nfs_page_to_folio(req));
 
1789		nfs_unlock_and_release_request(req);
1790	}
1791}
1792EXPORT_SYMBOL_GPL(nfs_retry_commit);
1793
1794static void nfs_commit_resched_write(struct nfs_commit_info *cinfo,
1795				     struct nfs_page *req)
 
1796{
1797	struct folio *folio = nfs_page_to_folio(req);
1798
1799	filemap_dirty_folio(folio_mapping(folio), folio);
1800}
1801
1802/*
1803 * Commit dirty pages
1804 */
1805static int
1806nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1807		struct nfs_commit_info *cinfo)
1808{
1809	struct nfs_commit_data	*data;
1810	struct nfsd_file *localio;
1811	unsigned short task_flags = 0;
1812
1813	/* another commit raced with us */
1814	if (list_empty(head))
1815		return 0;
1816
1817	data = nfs_commitdata_alloc();
1818	if (!data) {
1819		nfs_retry_commit(head, NULL, cinfo, -1);
1820		return -ENOMEM;
1821	}
1822
1823	/* Set up the argument struct */
1824	nfs_init_commit(data, head, NULL, cinfo);
1825	if (NFS_SERVER(inode)->nfs_client->cl_minorversion)
1826		task_flags = RPC_TASK_MOVEABLE;
1827
1828	localio = nfs_local_open_fh(NFS_SERVER(inode)->nfs_client, data->cred,
1829				    data->args.fh, data->context->mode);
1830	return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode),
1831				   data->mds_ops, how,
1832				   RPC_TASK_CRED_NOREF | task_flags, localio);
1833}
1834
1835/*
1836 * COMMIT call returned
1837 */
1838static void nfs_commit_done(struct rpc_task *task, void *calldata)
1839{
1840	struct nfs_commit_data	*data = calldata;
1841
1842	/* Call the NFS version-specific code */
1843	NFS_PROTO(data->inode)->commit_done(task, data);
1844	trace_nfs_commit_done(task, data);
1845}
1846
1847static void nfs_commit_release_pages(struct nfs_commit_data *data)
1848{
1849	const struct nfs_writeverf *verf = data->res.verf;
1850	struct nfs_page	*req;
1851	int status = data->task.tk_status;
1852	struct nfs_commit_info cinfo;
1853	struct folio *folio;
1854
1855	while (!list_empty(&data->pages)) {
1856		req = nfs_list_entry(data->pages.next);
1857		nfs_list_remove_request(req);
1858		folio = nfs_page_to_folio(req);
1859		nfs_folio_clear_commit(folio);
1860
1861		dprintk("NFS:       commit (%s/%llu %d@%lld)",
1862			nfs_req_openctx(req)->dentry->d_sb->s_id,
1863			(unsigned long long)NFS_FILEID(d_inode(nfs_req_openctx(req)->dentry)),
1864			req->wb_bytes,
1865			(long long)req_offset(req));
1866		if (status < 0) {
1867			if (folio) {
1868				trace_nfs_commit_error(data->inode, req,
1869						       status);
1870				nfs_mapping_set_error(folio, status);
1871				nfs_inode_remove_request(req);
1872			}
1873			dprintk_cont(", error = %d\n", status);
1874			goto next;
1875		}
1876
1877		/* Okay, COMMIT succeeded, apparently. Check the verifier
1878		 * returned by the server against all stored verfs. */
1879		if (nfs_write_match_verf(verf, req)) {
1880			/* We have a match */
1881			if (folio)
1882				nfs_inode_remove_request(req);
1883			dprintk_cont(" OK\n");
1884			goto next;
1885		}
1886		/* We have a mismatch. Write the page again */
1887		dprintk_cont(" mismatch\n");
1888		nfs_mark_request_dirty(req);
1889		atomic_long_inc(&NFS_I(data->inode)->redirtied_pages);
1890	next:
1891		nfs_unlock_and_release_request(req);
1892		/* Latency breaker */
1893		cond_resched();
1894	}
 
 
 
1895
1896	nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1897	nfs_commit_end(cinfo.mds);
1898}
1899
1900static void nfs_commit_release(void *calldata)
1901{
1902	struct nfs_commit_data *data = calldata;
1903
1904	data->completion_ops->completion(data);
1905	nfs_commitdata_release(calldata);
1906}
1907
1908static const struct rpc_call_ops nfs_commit_ops = {
1909	.rpc_call_prepare = nfs_commit_prepare,
1910	.rpc_call_done = nfs_commit_done,
1911	.rpc_release = nfs_commit_release,
1912};
1913
1914static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1915	.completion = nfs_commit_release_pages,
1916	.resched_write = nfs_commit_resched_write,
1917};
1918
1919int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1920			    int how, struct nfs_commit_info *cinfo)
1921{
1922	int status;
1923
1924	status = pnfs_commit_list(inode, head, how, cinfo);
1925	if (status == PNFS_NOT_ATTEMPTED)
1926		status = nfs_commit_list(inode, head, how, cinfo);
1927	return status;
1928}
1929
1930static int __nfs_commit_inode(struct inode *inode, int how,
1931		struct writeback_control *wbc)
1932{
1933	LIST_HEAD(head);
1934	struct nfs_commit_info cinfo;
1935	int may_wait = how & FLUSH_SYNC;
1936	int ret, nscan;
1937
1938	how &= ~FLUSH_SYNC;
1939	nfs_init_cinfo_from_inode(&cinfo, inode);
1940	nfs_commit_begin(cinfo.mds);
1941	for (;;) {
1942		ret = nscan = nfs_scan_commit(inode, &head, &cinfo);
1943		if (ret <= 0)
1944			break;
1945		ret = nfs_generic_commit_list(inode, &head, how, &cinfo);
1946		if (ret < 0)
1947			break;
1948		ret = 0;
1949		if (wbc && wbc->sync_mode == WB_SYNC_NONE) {
1950			if (nscan < wbc->nr_to_write)
1951				wbc->nr_to_write -= nscan;
1952			else
1953				wbc->nr_to_write = 0;
1954		}
1955		if (nscan < INT_MAX)
1956			break;
1957		cond_resched();
1958	}
1959	nfs_commit_end(cinfo.mds);
1960	if (ret || !may_wait)
1961		return ret;
1962	return wait_on_commit(cinfo.mds);
1963}
1964
1965int nfs_commit_inode(struct inode *inode, int how)
1966{
1967	return __nfs_commit_inode(inode, how, NULL);
1968}
1969EXPORT_SYMBOL_GPL(nfs_commit_inode);
1970
1971int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1972{
1973	struct nfs_inode *nfsi = NFS_I(inode);
1974	int flags = FLUSH_SYNC;
1975	int ret = 0;
1976
1977	if (wbc->sync_mode == WB_SYNC_NONE) {
1978		/* no commits means nothing needs to be done */
1979		if (!atomic_long_read(&nfsi->commit_info.ncommit))
1980			goto check_requests_outstanding;
1981
1982		/* Don't commit yet if this is a non-blocking flush and there
1983		 * are a lot of outstanding writes for this mapping.
1984		 */
1985		if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))
1986			goto out_mark_dirty;
1987
1988		/* don't wait for the COMMIT response */
1989		flags = 0;
1990	}
1991
1992	ret = __nfs_commit_inode(inode, flags, wbc);
1993	if (!ret) {
1994		if (flags & FLUSH_SYNC)
1995			return 0;
1996	} else if (atomic_long_read(&nfsi->commit_info.ncommit))
1997		goto out_mark_dirty;
1998
1999check_requests_outstanding:
2000	if (!atomic_read(&nfsi->commit_info.rpcs_out))
2001		return ret;
2002out_mark_dirty:
2003	__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
2004	return ret;
2005}
2006EXPORT_SYMBOL_GPL(nfs_write_inode);
2007
2008/*
2009 * Wrapper for filemap_write_and_wait_range()
2010 *
2011 * Needed for pNFS in order to ensure data becomes visible to the
2012 * client.
2013 */
2014int nfs_filemap_write_and_wait_range(struct address_space *mapping,
2015		loff_t lstart, loff_t lend)
2016{
2017	int ret;
2018
2019	ret = filemap_write_and_wait_range(mapping, lstart, lend);
2020	if (ret == 0)
2021		ret = pnfs_sync_inode(mapping->host, true);
2022	return ret;
2023}
2024EXPORT_SYMBOL_GPL(nfs_filemap_write_and_wait_range);
2025
2026/*
2027 * flush the inode to disk.
2028 */
2029int nfs_wb_all(struct inode *inode)
2030{
2031	int ret;
2032
2033	trace_nfs_writeback_inode_enter(inode);
2034
2035	ret = filemap_write_and_wait(inode->i_mapping);
2036	if (ret)
2037		goto out;
2038	ret = nfs_commit_inode(inode, FLUSH_SYNC);
2039	if (ret < 0)
2040		goto out;
2041	pnfs_sync_inode(inode, true);
2042	ret = 0;
2043
2044out:
2045	trace_nfs_writeback_inode_exit(inode, ret);
2046	return ret;
2047}
2048EXPORT_SYMBOL_GPL(nfs_wb_all);
2049
2050int nfs_wb_folio_cancel(struct inode *inode, struct folio *folio)
2051{
2052	struct nfs_page *req;
2053	int ret = 0;
2054
2055	folio_wait_writeback(folio);
2056
2057	/* blocking call to cancel all requests and join to a single (head)
2058	 * request */
2059	req = nfs_lock_and_join_requests(folio);
2060
2061	if (IS_ERR(req)) {
2062		ret = PTR_ERR(req);
2063	} else if (req) {
2064		/* all requests from this folio have been cancelled by
2065		 * nfs_lock_and_join_requests, so just remove the head
2066		 * request from the inode / page_private pointer and
2067		 * release it */
2068		nfs_inode_remove_request(req);
2069		nfs_unlock_and_release_request(req);
2070	}
2071
2072	return ret;
2073}
2074
2075/**
2076 * nfs_wb_folio - Write back all requests on one page
2077 * @inode: pointer to page
2078 * @folio: pointer to folio
2079 *
2080 * Assumes that the folio has been locked by the caller, and will
2081 * not unlock it.
2082 */
2083int nfs_wb_folio(struct inode *inode, struct folio *folio)
2084{
2085	loff_t range_start = folio_pos(folio);
2086	size_t len = folio_size(folio);
2087	struct writeback_control wbc = {
2088		.sync_mode = WB_SYNC_ALL,
2089		.nr_to_write = 0,
2090		.range_start = range_start,
2091		.range_end = range_start + len - 1,
2092	};
2093	int ret;
2094
2095	trace_nfs_writeback_folio(inode, range_start, len);
2096
2097	for (;;) {
2098		folio_wait_writeback(folio);
2099		if (folio_clear_dirty_for_io(folio)) {
2100			ret = nfs_writepage_locked(folio, &wbc);
2101			if (ret < 0)
2102				goto out_error;
2103			continue;
2104		}
2105		ret = 0;
2106		if (!folio_test_private(folio))
2107			break;
2108		ret = nfs_commit_inode(inode, FLUSH_SYNC);
2109		if (ret < 0)
2110			goto out_error;
2111	}
2112out_error:
2113	trace_nfs_writeback_folio_done(inode, range_start, len, ret);
2114	return ret;
2115}
2116
2117#ifdef CONFIG_MIGRATION
2118int nfs_migrate_folio(struct address_space *mapping, struct folio *dst,
2119		struct folio *src, enum migrate_mode mode)
2120{
2121	/*
2122	 * If the private flag is set, the folio is currently associated with
2123	 * an in-progress read or write request. Don't try to migrate it.
2124	 *
2125	 * FIXME: we could do this in principle, but we'll need a way to ensure
2126	 *        that we can safely release the inode reference while holding
2127	 *        the folio lock.
2128	 */
2129	if (folio_test_private(src))
2130		return -EBUSY;
2131
2132	if (folio_test_private_2(src)) { /* [DEPRECATED] */
2133		if (mode == MIGRATE_ASYNC)
2134			return -EBUSY;
2135		folio_wait_private_2(src);
2136	}
2137
2138	return migrate_folio(mapping, dst, src, mode);
2139}
2140#endif
2141
2142int __init nfs_init_writepagecache(void)
2143{
2144	nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
2145					     sizeof(struct nfs_pgio_header),
2146					     0, SLAB_HWCACHE_ALIGN,
2147					     NULL);
2148	if (nfs_wdata_cachep == NULL)
2149		return -ENOMEM;
2150
2151	nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
2152						     nfs_wdata_cachep);
2153	if (nfs_wdata_mempool == NULL)
2154		goto out_destroy_write_cache;
2155
2156	nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
2157					     sizeof(struct nfs_commit_data),
2158					     0, SLAB_HWCACHE_ALIGN,
2159					     NULL);
2160	if (nfs_cdata_cachep == NULL)
2161		goto out_destroy_write_mempool;
2162
2163	nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
2164						      nfs_cdata_cachep);
2165	if (nfs_commit_mempool == NULL)
2166		goto out_destroy_commit_cache;
2167
2168	/*
2169	 * NFS congestion size, scale with available memory.
2170	 *
2171	 *  64MB:    8192k
2172	 * 128MB:   11585k
2173	 * 256MB:   16384k
2174	 * 512MB:   23170k
2175	 *   1GB:   32768k
2176	 *   2GB:   46340k
2177	 *   4GB:   65536k
2178	 *   8GB:   92681k
2179	 *  16GB:  131072k
2180	 *
2181	 * This allows larger machines to have larger/more transfers.
2182	 * Limit the default to 256M
2183	 */
2184	nfs_congestion_kb = (16*int_sqrt(totalram_pages())) << (PAGE_SHIFT-10);
2185	if (nfs_congestion_kb > 256*1024)
2186		nfs_congestion_kb = 256*1024;
2187
2188	return 0;
2189
2190out_destroy_commit_cache:
2191	kmem_cache_destroy(nfs_cdata_cachep);
2192out_destroy_write_mempool:
2193	mempool_destroy(nfs_wdata_mempool);
2194out_destroy_write_cache:
2195	kmem_cache_destroy(nfs_wdata_cachep);
2196	return -ENOMEM;
2197}
2198
2199void nfs_destroy_writepagecache(void)
2200{
2201	mempool_destroy(nfs_commit_mempool);
2202	kmem_cache_destroy(nfs_cdata_cachep);
2203	mempool_destroy(nfs_wdata_mempool);
2204	kmem_cache_destroy(nfs_wdata_cachep);
2205}
2206
2207static const struct nfs_rw_ops nfs_rw_write_ops = {
2208	.rw_alloc_header	= nfs_writehdr_alloc,
2209	.rw_free_header		= nfs_writehdr_free,
2210	.rw_done		= nfs_writeback_done,
2211	.rw_result		= nfs_writeback_result,
2212	.rw_initiate		= nfs_initiate_write,
2213};