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