1/*
   2 * linux/fs/nfs/write.c
   3 *
   4 * Write file data over NFS.
   5 *
   6 * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
   7 */
   8
   9#include <linux/types.h>
  10#include <linux/slab.h>
  11#include <linux/mm.h>
  12#include <linux/pagemap.h>
  13#include <linux/file.h>
  14#include <linux/writeback.h>
  15#include <linux/swap.h>
  16#include <linux/migrate.h>
  17
  18#include <linux/sunrpc/clnt.h>
  19#include <linux/nfs_fs.h>
  20#include <linux/nfs_mount.h>
  21#include <linux/nfs_page.h>
  22#include <linux/backing-dev.h>
  23#include <linux/export.h>
 
 
 
  24
  25#include <asm/uaccess.h>
 
  26
  27#include "delegation.h"
  28#include "internal.h"
  29#include "iostat.h"
  30#include "nfs4_fs.h"
  31#include "fscache.h"
  32#include "pnfs.h"
  33
  34#include "nfstrace.h"
  35
  36#define NFSDBG_FACILITY		NFSDBG_PAGECACHE
  37
  38#define MIN_POOL_WRITE		(32)
  39#define MIN_POOL_COMMIT		(4)
  40
 
 
 
 
 
 
  41/*
  42 * Local function declarations
  43 */
  44static void nfs_redirty_request(struct nfs_page *req);
  45static const struct rpc_call_ops nfs_write_common_ops;
  46static const struct rpc_call_ops nfs_commit_ops;
  47static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
  48static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
 
 
 
 
 
 
 
 
  49
  50static struct kmem_cache *nfs_wdata_cachep;
  51static mempool_t *nfs_wdata_mempool;
  52static struct kmem_cache *nfs_cdata_cachep;
  53static mempool_t *nfs_commit_mempool;
  54
  55struct nfs_commit_data *nfs_commitdata_alloc(void)
  56{
  57	struct nfs_commit_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);
  58
  59	if (p) {
  60		memset(p, 0, sizeof(*p));
  61		INIT_LIST_HEAD(&p->pages);
 
 
 
 
 
 
 
 
 
 
 
  62	}
 
 
 
  63	return p;
  64}
  65EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
  66
  67void nfs_commit_free(struct nfs_commit_data *p)
  68{
  69	mempool_free(p, nfs_commit_mempool);
  70}
  71EXPORT_SYMBOL_GPL(nfs_commit_free);
  72
  73struct nfs_write_header *nfs_writehdr_alloc(void)
  74{
  75	struct nfs_write_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);
  76
  77	if (p) {
  78		struct nfs_pgio_header *hdr = &p->header;
  79
  80		memset(p, 0, sizeof(*p));
  81		INIT_LIST_HEAD(&hdr->pages);
  82		INIT_LIST_HEAD(&hdr->rpc_list);
  83		spin_lock_init(&hdr->lock);
  84		atomic_set(&hdr->refcnt, 0);
  85		hdr->verf = &p->verf;
  86	}
  87	return p;
  88}
  89EXPORT_SYMBOL_GPL(nfs_writehdr_alloc);
  90
  91static struct nfs_write_data *nfs_writedata_alloc(struct nfs_pgio_header *hdr,
  92						  unsigned int pagecount)
  93{
  94	struct nfs_write_data *data, *prealloc;
 
  95
  96	prealloc = &container_of(hdr, struct nfs_write_header, header)->rpc_data;
  97	if (prealloc->header == NULL)
  98		data = prealloc;
  99	else
 100		data = kzalloc(sizeof(*data), GFP_KERNEL);
 101	if (!data)
 102		goto out;
 103
 104	if (nfs_pgarray_set(&data->pages, pagecount)) {
 105		data->header = hdr;
 106		atomic_inc(&hdr->refcnt);
 107	} else {
 108		if (data != prealloc)
 109			kfree(data);
 110		data = NULL;
 111	}
 112out:
 113	return data;
 114}
 115
 116void nfs_writehdr_free(struct nfs_pgio_header *hdr)
 117{
 118	struct nfs_write_header *whdr = container_of(hdr, struct nfs_write_header, header);
 119	mempool_free(whdr, nfs_wdata_mempool);
 
 
 120}
 121EXPORT_SYMBOL_GPL(nfs_writehdr_free);
 122
 123void nfs_writedata_release(struct nfs_write_data *wdata)
 124{
 125	struct nfs_pgio_header *hdr = wdata->header;
 126	struct nfs_write_header *write_header = container_of(hdr, struct nfs_write_header, header);
 
 127
 128	put_nfs_open_context(wdata->args.context);
 129	if (wdata->pages.pagevec != wdata->pages.page_array)
 130		kfree(wdata->pages.pagevec);
 131	if (wdata == &write_header->rpc_data) {
 132		wdata->header = NULL;
 133		wdata = NULL;
 
 
 
 
 
 
 134	}
 135	if (atomic_dec_and_test(&hdr->refcnt))
 136		hdr->completion_ops->completion(hdr);
 137	/* Note: we only free the rpc_task after callbacks are done.
 138	 * See the comment in rpc_free_task() for why
 139	 */
 140	kfree(wdata);
 141}
 142EXPORT_SYMBOL_GPL(nfs_writedata_release);
 143
 144static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
 
 145{
 146	ctx->error = error;
 147	smp_wmb();
 148	set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 
 
 
 
 
 
 
 
 149}
 150
 151static struct nfs_page *
 152nfs_page_find_request_locked(struct nfs_inode *nfsi, struct page *page)
 153{
 154	struct nfs_page *req = NULL;
 
 
 
 155
 156	if (PagePrivate(page))
 157		req = (struct nfs_page *)page_private(page);
 158	else if (unlikely(PageSwapCache(page))) {
 159		struct nfs_page *freq, *t;
 160
 161		/* Linearly search the commit list for the correct req */
 162		list_for_each_entry_safe(freq, t, &nfsi->commit_info.list, wb_list) {
 163			if (freq->wb_page == page) {
 164				req = freq;
 165				break;
 166			}
 167		}
 168	}
 169
 170	if (req)
 
 
 
 
 
 171		kref_get(&req->wb_kref);
 172
 
 173	return req;
 174}
 175
 176static struct nfs_page *nfs_page_find_request(struct page *page)
 
 177{
 178	struct inode *inode = page_file_mapping(page)->host;
 
 179	struct nfs_page *req = NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 180
 181	spin_lock(&inode->i_lock);
 182	req = nfs_page_find_request_locked(NFS_I(inode), page);
 183	spin_unlock(&inode->i_lock);
 
 
 
 
 
 
 
 
 
 184	return req;
 185}
 186
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 187/* Adjust the file length if we're writing beyond the end */
 188static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
 189{
 190	struct inode *inode = page_file_mapping(page)->host;
 191	loff_t end, i_size;
 192	pgoff_t end_index;
 193
 194	spin_lock(&inode->i_lock);
 195	i_size = i_size_read(inode);
 196	end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
 197	if (i_size > 0 && page_file_index(page) < end_index)
 198		goto out;
 199	end = page_file_offset(page) + ((loff_t)offset+count);
 200	if (i_size >= end)
 201		goto out;
 202	i_size_write(inode, end);
 
 203	nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 204out:
 205	spin_unlock(&inode->i_lock);
 206}
 207
 208/* A writeback failed: mark the page as bad, and invalidate the page cache */
 209static void nfs_set_pageerror(struct page *page)
 210{
 211	nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 212}
 213
 214/* We can set the PG_uptodate flag if we see that a write request
 215 * covers the full page.
 216 */
 217static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
 218{
 219	if (PageUptodate(page))
 220		return;
 221	if (base != 0)
 222		return;
 223	if (count != nfs_page_length(page))
 224		return;
 225	SetPageUptodate(page);
 226}
 227
 228static int wb_priority(struct writeback_control *wbc)
 229{
 230	if (wbc->for_reclaim)
 231		return FLUSH_HIGHPRI | FLUSH_STABLE;
 232	if (wbc->for_kupdate || wbc->for_background)
 233		return FLUSH_LOWPRI | FLUSH_COND_STABLE;
 234	return FLUSH_COND_STABLE;
 235}
 236
 237/*
 238 * NFS congestion control
 239 */
 240
 241int nfs_congestion_kb;
 242
 243#define NFS_CONGESTION_ON_THRESH 	(nfs_congestion_kb >> (PAGE_SHIFT-10))
 244#define NFS_CONGESTION_OFF_THRESH	\
 245	(NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 246
 247static void nfs_set_page_writeback(struct page *page)
 248{
 249	struct nfs_server *nfss = NFS_SERVER(page_file_mapping(page)->host);
 
 250	int ret = test_set_page_writeback(page);
 251
 252	WARN_ON_ONCE(ret != 0);
 253
 254	if (atomic_long_inc_return(&nfss->writeback) >
 255			NFS_CONGESTION_ON_THRESH) {
 256		set_bdi_congested(&nfss->backing_dev_info,
 257					BLK_RW_ASYNC);
 258	}
 259}
 260
 261static void nfs_end_page_writeback(struct page *page)
 262{
 263	struct inode *inode = page_file_mapping(page)->host;
 264	struct nfs_server *nfss = NFS_SERVER(inode);
 
 265
 266	end_page_writeback(page);
 
 
 
 
 
 267	if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
 268		clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 269}
 270
 271static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblock)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 272{
 273	struct inode *inode = page_file_mapping(page)->host;
 274	struct nfs_page *req;
 275	int ret;
 276
 277	spin_lock(&inode->i_lock);
 278	for (;;) {
 279		req = nfs_page_find_request_locked(NFS_I(inode), page);
 280		if (req == NULL)
 281			break;
 282		if (nfs_lock_request(req))
 283			break;
 284		/* Note: If we hold the page lock, as is the case in nfs_writepage,
 285		 *	 then the call to nfs_lock_request() will always
 286		 *	 succeed provided that someone hasn't already marked the
 287		 *	 request as dirty (in which case we don't care).
 288		 */
 289		spin_unlock(&inode->i_lock);
 290		if (!nonblock)
 291			ret = nfs_wait_on_request(req);
 292		else
 293			ret = -EAGAIN;
 294		nfs_release_request(req);
 295		if (ret != 0)
 296			return ERR_PTR(ret);
 297		spin_lock(&inode->i_lock);
 298	}
 299	spin_unlock(&inode->i_lock);
 300	return req;
 
 
 
 
 
 
 
 
 
 
 
 301}
 302
 303/*
 304 * Find an associated nfs write request, and prepare to flush it out
 305 * May return an error if the user signalled nfs_wait_on_request().
 306 */
 307static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 308				struct page *page, bool nonblock)
 309{
 310	struct nfs_page *req;
 311	int ret = 0;
 312
 313	req = nfs_find_and_lock_request(page, nonblock);
 314	if (!req)
 315		goto out;
 316	ret = PTR_ERR(req);
 317	if (IS_ERR(req))
 318		goto out;
 319
 320	nfs_set_page_writeback(page);
 321	WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
 322
 
 
 
 
 
 323	ret = 0;
 324	if (!nfs_pageio_add_request(pgio, req)) {
 325		nfs_redirty_request(req);
 326		ret = pgio->pg_error;
 327	}
 
 
 
 
 
 
 
 
 
 
 
 
 328out:
 329	return ret;
 
 
 
 330}
 331
 332static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
 
 333{
 334	struct inode *inode = page_file_mapping(page)->host;
 335	int ret;
 336
 337	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 338	nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 339
 340	nfs_pageio_cond_complete(pgio, page_file_index(page));
 341	ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
 342	if (ret == -EAGAIN) {
 343		redirty_page_for_writepage(wbc, page);
 344		ret = 0;
 345	}
 346	return ret;
 347}
 348
 349/*
 350 * Write an mmapped page to the server.
 351 */
 352static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 
 353{
 354	struct nfs_pageio_descriptor pgio;
 
 355	int err;
 356
 357	NFS_PROTO(page_file_mapping(page)->host)->write_pageio_init(&pgio,
 358							  page->mapping->host,
 359							  wb_priority(wbc),
 360							  &nfs_async_write_completion_ops);
 361	err = nfs_do_writepage(page, wbc, &pgio);
 
 362	nfs_pageio_complete(&pgio);
 363	if (err < 0)
 364		return err;
 365	if (pgio.pg_error < 0)
 366		return pgio.pg_error;
 367	return 0;
 368}
 369
 370int nfs_writepage(struct page *page, struct writeback_control *wbc)
 371{
 372	int ret;
 373
 374	ret = nfs_writepage_locked(page, wbc);
 375	unlock_page(page);
 
 376	return ret;
 377}
 378
 379static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
 380{
 381	int ret;
 382
 383	ret = nfs_do_writepage(page, wbc, data);
 384	unlock_page(page);
 
 385	return ret;
 386}
 387
 
 
 
 
 
 388int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 389{
 390	struct inode *inode = mapping->host;
 391	unsigned long *bitlock = &NFS_I(inode)->flags;
 392	struct nfs_pageio_descriptor pgio;
 
 
 
 393	int err;
 394
 395	/* Stop dirtying of new pages while we sync */
 396	err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
 397			nfs_wait_bit_killable, TASK_KILLABLE);
 398	if (err)
 399		goto out_err;
 400
 401	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 402
 403	NFS_PROTO(inode)->write_pageio_init(&pgio, inode, wb_priority(wbc), &nfs_async_write_completion_ops);
 
 
 
 
 
 
 
 
 
 
 
 404	err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
 
 405	nfs_pageio_complete(&pgio);
 406
 407	clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
 408	smp_mb__after_clear_bit();
 409	wake_up_bit(bitlock, NFS_INO_FLUSHING);
 410
 411	if (err < 0)
 412		goto out_err;
 413	err = pgio.pg_error;
 414	if (err < 0)
 415		goto out_err;
 416	return 0;
 417out_err:
 418	return err;
 419}
 420
 421/*
 422 * Insert a write request into an inode
 423 */
 424static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 425{
 
 426	struct nfs_inode *nfsi = NFS_I(inode);
 427
 
 
 428	/* Lock the request! */
 429	nfs_lock_request(req);
 430
 431	spin_lock(&inode->i_lock);
 432	if (!nfsi->npages && NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
 433		inode->i_version++;
 434	/*
 435	 * Swap-space should not get truncated. Hence no need to plug the race
 436	 * with invalidate/truncate.
 437	 */
 
 438	if (likely(!PageSwapCache(req->wb_page))) {
 439		set_bit(PG_MAPPED, &req->wb_flags);
 440		SetPagePrivate(req->wb_page);
 441		set_page_private(req->wb_page, (unsigned long)req);
 442	}
 443	nfsi->npages++;
 
 
 
 
 
 
 444	kref_get(&req->wb_kref);
 445	spin_unlock(&inode->i_lock);
 446}
 447
 448/*
 449 * Remove a write request from an inode
 450 */
 451static void nfs_inode_remove_request(struct nfs_page *req)
 452{
 453	struct inode *inode = req->wb_context->dentry->d_inode;
 
 454	struct nfs_inode *nfsi = NFS_I(inode);
 
 455
 456	spin_lock(&inode->i_lock);
 457	if (likely(!PageSwapCache(req->wb_page))) {
 458		set_page_private(req->wb_page, 0);
 459		ClearPagePrivate(req->wb_page);
 460		clear_bit(PG_MAPPED, &req->wb_flags);
 
 
 
 
 
 
 
 
 
 
 461	}
 462	nfsi->npages--;
 463	spin_unlock(&inode->i_lock);
 464	nfs_release_request(req);
 465}
 466
 467static void
 468nfs_mark_request_dirty(struct nfs_page *req)
 469{
 470	__set_page_dirty_nobuffers(req->wb_page);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 471}
 472
 473#if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4)
 474/**
 475 * nfs_request_add_commit_list - add request to a commit list
 476 * @req: pointer to a struct nfs_page
 477 * @dst: commit list head
 478 * @cinfo: holds list lock and accounting info
 479 *
 480 * This sets the PG_CLEAN bit, updates the cinfo count of
 481 * number of outstanding requests requiring a commit as well as
 482 * the MM page stats.
 483 *
 484 * The caller must _not_ hold the cinfo->lock, but must be
 485 * holding the nfs_page lock.
 486 */
 487void
 488nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst,
 489			    struct nfs_commit_info *cinfo)
 490{
 491	set_bit(PG_CLEAN, &(req)->wb_flags);
 492	spin_lock(cinfo->lock);
 493	nfs_list_add_request(req, dst);
 494	cinfo->mds->ncommit++;
 495	spin_unlock(cinfo->lock);
 496	if (!cinfo->dreq) {
 497		inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 498		inc_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
 499			     BDI_RECLAIMABLE);
 500		__mark_inode_dirty(req->wb_context->dentry->d_inode,
 501				   I_DIRTY_DATASYNC);
 502	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 503}
 504EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
 505
 506/**
 507 * nfs_request_remove_commit_list - Remove request from a commit list
 508 * @req: pointer to a nfs_page
 509 * @cinfo: holds list lock and accounting info
 510 *
 511 * This clears the PG_CLEAN bit, and updates the cinfo's count of
 512 * number of outstanding requests requiring a commit
 513 * It does not update the MM page stats.
 514 *
 515 * The caller _must_ hold the cinfo->lock and the nfs_page lock.
 516 */
 517void
 518nfs_request_remove_commit_list(struct nfs_page *req,
 519			       struct nfs_commit_info *cinfo)
 520{
 521	if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
 522		return;
 523	nfs_list_remove_request(req);
 524	cinfo->mds->ncommit--;
 525}
 526EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
 527
 528static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
 529				      struct inode *inode)
 530{
 531	cinfo->lock = &inode->i_lock;
 532	cinfo->mds = &NFS_I(inode)->commit_info;
 533	cinfo->ds = pnfs_get_ds_info(inode);
 534	cinfo->dreq = NULL;
 535	cinfo->completion_ops = &nfs_commit_completion_ops;
 536}
 537
 538void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 539		    struct inode *inode,
 540		    struct nfs_direct_req *dreq)
 541{
 542	if (dreq)
 543		nfs_init_cinfo_from_dreq(cinfo, dreq);
 544	else
 545		nfs_init_cinfo_from_inode(cinfo, inode);
 546}
 547EXPORT_SYMBOL_GPL(nfs_init_cinfo);
 548
 549/*
 550 * Add a request to the inode's commit list.
 551 */
 552void
 553nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
 554			struct nfs_commit_info *cinfo)
 555{
 556	if (pnfs_mark_request_commit(req, lseg, cinfo))
 557		return;
 558	nfs_request_add_commit_list(req, &cinfo->mds->list, cinfo);
 559}
 560
 561static void
 562nfs_clear_page_commit(struct page *page)
 563{
 564	dec_zone_page_state(page, NR_UNSTABLE_NFS);
 565	dec_bdi_stat(page_file_mapping(page)->backing_dev_info, BDI_RECLAIMABLE);
 
 566}
 567
 
 568static void
 569nfs_clear_request_commit(struct nfs_page *req)
 570{
 571	if (test_bit(PG_CLEAN, &req->wb_flags)) {
 572		struct inode *inode = req->wb_context->dentry->d_inode;
 
 573		struct nfs_commit_info cinfo;
 574
 575		nfs_init_cinfo_from_inode(&cinfo, inode);
 
 576		if (!pnfs_clear_request_commit(req, &cinfo)) {
 577			spin_lock(cinfo.lock);
 578			nfs_request_remove_commit_list(req, &cinfo);
 579			spin_unlock(cinfo.lock);
 580		}
 
 581		nfs_clear_page_commit(req->wb_page);
 582	}
 583}
 584
 585static inline
 586int nfs_write_need_commit(struct nfs_write_data *data)
 587{
 588	if (data->verf.committed == NFS_DATA_SYNC)
 589		return data->header->lseg == NULL;
 590	return data->verf.committed != NFS_FILE_SYNC;
 591}
 592
 593#else
 594static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
 595				      struct inode *inode)
 596{
 597}
 598
 599void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 600		    struct inode *inode,
 601		    struct nfs_direct_req *dreq)
 602{
 
 
 
 603}
 604
 605void
 606nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
 607			struct nfs_commit_info *cinfo)
 608{
 
 609}
 610
 611static void
 612nfs_clear_request_commit(struct nfs_page *req)
 613{
 614}
 615
 616static inline
 617int nfs_write_need_commit(struct nfs_write_data *data)
 618{
 619	return 0;
 620}
 621
 622#endif
 623
 624static void nfs_write_completion(struct nfs_pgio_header *hdr)
 625{
 626	struct nfs_commit_info cinfo;
 627	unsigned long bytes = 0;
 628
 629	if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
 630		goto out;
 631	nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
 632	while (!list_empty(&hdr->pages)) {
 633		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
 634
 635		bytes += req->wb_bytes;
 636		nfs_list_remove_request(req);
 637		if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
 638		    (hdr->good_bytes < bytes)) {
 639			nfs_set_pageerror(req->wb_page);
 640			nfs_context_set_write_error(req->wb_context, hdr->error);
 641			goto remove_req;
 642		}
 643		if (test_bit(NFS_IOHDR_NEED_RESCHED, &hdr->flags)) {
 644			nfs_mark_request_dirty(req);
 645			goto next;
 646		}
 647		if (test_bit(NFS_IOHDR_NEED_COMMIT, &hdr->flags)) {
 648			memcpy(&req->wb_verf, &hdr->verf->verifier, sizeof(req->wb_verf));
 649			nfs_mark_request_commit(req, hdr->lseg, &cinfo);
 650			goto next;
 651		}
 652remove_req:
 653		nfs_inode_remove_request(req);
 654next:
 655		nfs_unlock_request(req);
 656		nfs_end_page_writeback(req->wb_page);
 657		nfs_release_request(req);
 658	}
 659out:
 
 660	hdr->release(hdr);
 661}
 662
 663#if  IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4)
 664static unsigned long
 665nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
 666{
 667	return cinfo->mds->ncommit;
 668}
 669
 670/* cinfo->lock held by caller */
 671int
 672nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
 673		     struct nfs_commit_info *cinfo, int max)
 674{
 675	struct nfs_page *req, *tmp;
 676	int ret = 0;
 677
 
 678	list_for_each_entry_safe(req, tmp, src, wb_list) {
 679		if (!nfs_lock_request(req))
 680			continue;
 681		kref_get(&req->wb_kref);
 682		if (cond_resched_lock(cinfo->lock))
 683			list_safe_reset_next(req, tmp, wb_list);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 684		nfs_request_remove_commit_list(req, cinfo);
 
 685		nfs_list_add_request(req, dst);
 686		ret++;
 687		if ((ret == max) && !cinfo->dreq)
 688			break;
 
 689	}
 690	return ret;
 691}
 
 692
 693/*
 694 * nfs_scan_commit - Scan an inode for commit requests
 695 * @inode: NFS inode to scan
 696 * @dst: mds destination list
 697 * @cinfo: mds and ds lists of reqs ready to commit
 698 *
 699 * Moves requests from the inode's 'commit' request list.
 700 * The requests are *not* checked to ensure that they form a contiguous set.
 701 */
 702int
 703nfs_scan_commit(struct inode *inode, struct list_head *dst,
 704		struct nfs_commit_info *cinfo)
 705{
 706	int ret = 0;
 707
 708	spin_lock(cinfo->lock);
 709	if (cinfo->mds->ncommit > 0) {
 
 
 710		const int max = INT_MAX;
 711
 712		ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
 713					   cinfo, max);
 714		ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
 715	}
 716	spin_unlock(cinfo->lock);
 717	return ret;
 718}
 719
 720#else
 721static unsigned long nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
 722{
 723	return 0;
 724}
 725
 726int nfs_scan_commit(struct inode *inode, struct list_head *dst,
 727		    struct nfs_commit_info *cinfo)
 728{
 729	return 0;
 730}
 731#endif
 732
 733/*
 734 * Search for an existing write request, and attempt to update
 735 * it to reflect a new dirty region on a given page.
 736 *
 737 * If the attempt fails, then the existing request is flushed out
 738 * to disk.
 739 */
 740static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
 741		struct page *page,
 742		unsigned int offset,
 743		unsigned int bytes)
 744{
 745	struct nfs_page *req;
 746	unsigned int rqend;
 747	unsigned int end;
 748	int error;
 749
 750	if (!PagePrivate(page))
 751		return NULL;
 752
 753	end = offset + bytes;
 754	spin_lock(&inode->i_lock);
 755
 756	for (;;) {
 757		req = nfs_page_find_request_locked(NFS_I(inode), page);
 758		if (req == NULL)
 759			goto out_unlock;
 760
 761		rqend = req->wb_offset + req->wb_bytes;
 762		/*
 763		 * Tell the caller to flush out the request if
 764		 * the offsets are non-contiguous.
 765		 * Note: nfs_flush_incompatible() will already
 766		 * have flushed out requests having wrong owners.
 767		 */
 768		if (offset > rqend
 769		    || end < req->wb_offset)
 770			goto out_flushme;
 771
 772		if (nfs_lock_request(req))
 773			break;
 
 774
 775		/* The request is locked, so wait and then retry */
 776		spin_unlock(&inode->i_lock);
 777		error = nfs_wait_on_request(req);
 778		nfs_release_request(req);
 779		if (error != 0)
 780			goto out_err;
 781		spin_lock(&inode->i_lock);
 782	}
 
 783
 784	/* Okay, the request matches. Update the region */
 785	if (offset < req->wb_offset) {
 786		req->wb_offset = offset;
 787		req->wb_pgbase = offset;
 788	}
 789	if (end > rqend)
 790		req->wb_bytes = end - req->wb_offset;
 791	else
 792		req->wb_bytes = rqend - req->wb_offset;
 793out_unlock:
 794	spin_unlock(&inode->i_lock);
 795	if (req)
 796		nfs_clear_request_commit(req);
 797	return req;
 798out_flushme:
 799	spin_unlock(&inode->i_lock);
 800	nfs_release_request(req);
 
 
 
 
 
 801	error = nfs_wb_page(inode, page);
 802out_err:
 803	return ERR_PTR(error);
 804}
 805
 806/*
 807 * Try to update an existing write request, or create one if there is none.
 808 *
 809 * Note: Should always be called with the Page Lock held to prevent races
 810 * if we have to add a new request. Also assumes that the caller has
 811 * already called nfs_flush_incompatible() if necessary.
 812 */
 813static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
 814		struct page *page, unsigned int offset, unsigned int bytes)
 815{
 816	struct inode *inode = page_file_mapping(page)->host;
 817	struct nfs_page	*req;
 818
 819	req = nfs_try_to_update_request(inode, page, offset, bytes);
 820	if (req != NULL)
 821		goto out;
 822	req = nfs_create_request(ctx, inode, page, offset, bytes);
 823	if (IS_ERR(req))
 824		goto out;
 825	nfs_inode_add_request(inode, req);
 826out:
 827	return req;
 828}
 829
 830static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 831		unsigned int offset, unsigned int count)
 832{
 833	struct nfs_page	*req;
 834
 835	req = nfs_setup_write_request(ctx, page, offset, count);
 836	if (IS_ERR(req))
 837		return PTR_ERR(req);
 838	/* Update file length */
 839	nfs_grow_file(page, offset, count);
 840	nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
 841	nfs_mark_request_dirty(req);
 842	nfs_unlock_and_release_request(req);
 843	return 0;
 844}
 845
 846int nfs_flush_incompatible(struct file *file, struct page *page)
 847{
 848	struct nfs_open_context *ctx = nfs_file_open_context(file);
 849	struct nfs_lock_context *l_ctx;
 
 850	struct nfs_page	*req;
 851	int do_flush, status;
 852	/*
 853	 * Look for a request corresponding to this page. If there
 854	 * is one, and it belongs to another file, we flush it out
 855	 * before we try to copy anything into the page. Do this
 856	 * due to the lack of an ACCESS-type call in NFSv2.
 857	 * Also do the same if we find a request from an existing
 858	 * dropped page.
 859	 */
 860	do {
 861		req = nfs_page_find_request(page);
 862		if (req == NULL)
 863			return 0;
 864		l_ctx = req->wb_lock_context;
 865		do_flush = req->wb_page != page || req->wb_context != ctx;
 866		if (l_ctx && ctx->dentry->d_inode->i_flock != NULL) {
 867			do_flush |= l_ctx->lockowner.l_owner != current->files
 868				|| l_ctx->lockowner.l_pid != current->tgid;
 
 
 869		}
 870		nfs_release_request(req);
 871		if (!do_flush)
 872			return 0;
 873		status = nfs_wb_page(page_file_mapping(page)->host, page);
 874	} while (status == 0);
 875	return status;
 876}
 877
 878/*
 879 * Avoid buffered writes when a open context credential's key would
 880 * expire soon.
 881 *
 882 * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
 883 *
 884 * Return 0 and set a credential flag which triggers the inode to flush
 885 * and performs  NFS_FILE_SYNC writes if the key will expired within
 886 * RPC_KEY_EXPIRE_TIMEO.
 887 */
 888int
 889nfs_key_timeout_notify(struct file *filp, struct inode *inode)
 890{
 891	struct nfs_open_context *ctx = nfs_file_open_context(filp);
 892	struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
 893
 894	return rpcauth_key_timeout_notify(auth, ctx->cred);
 
 
 
 
 895}
 896
 897/*
 898 * Test if the open context credential key is marked to expire soon.
 899 */
 900bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx)
 901{
 902	return rpcauth_cred_key_to_expire(ctx->cred);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 903}
 904
 905/*
 906 * If the page cache is marked as unsafe or invalid, then we can't rely on
 907 * the PageUptodate() flag. In this case, we will need to turn off
 908 * write optimisations that depend on the page contents being correct.
 909 */
 910static bool nfs_write_pageuptodate(struct page *page, struct inode *inode)
 
 911{
 912	struct nfs_inode *nfsi = NFS_I(inode);
 913
 914	if (nfs_have_delegated_attributes(inode))
 915		goto out;
 916	if (nfsi->cache_validity & (NFS_INO_INVALID_DATA|NFS_INO_REVAL_PAGECACHE))
 
 917		return false;
 918	smp_rmb();
 919	if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags))
 920		return false;
 921out:
 
 
 922	return PageUptodate(page) != 0;
 923}
 924
 
 
 
 
 
 
 
 925/* If we know the page is up to date, and we're not using byte range locks (or
 926 * if we have the whole file locked for writing), it may be more efficient to
 927 * extend the write to cover the entire page in order to avoid fragmentation
 928 * inefficiencies.
 929 *
 930 * If the file is opened for synchronous writes then we can just skip the rest
 931 * of the checks.
 932 */
 933static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode)
 
 934{
 
 
 
 
 935	if (file->f_flags & O_DSYNC)
 936		return 0;
 937	if (!nfs_write_pageuptodate(page, inode))
 938		return 0;
 939	if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
 940		return 1;
 941	if (inode->i_flock == NULL || (inode->i_flock->fl_start == 0 &&
 942			inode->i_flock->fl_end == OFFSET_MAX &&
 943			inode->i_flock->fl_type != F_RDLCK))
 944		return 1;
 945	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 946}
 947
 948/*
 949 * Update and possibly write a cached page of an NFS file.
 950 *
 951 * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
 952 * things with a page scheduled for an RPC call (e.g. invalidate it).
 953 */
 954int nfs_updatepage(struct file *file, struct page *page,
 955		unsigned int offset, unsigned int count)
 956{
 957	struct nfs_open_context *ctx = nfs_file_open_context(file);
 958	struct inode	*inode = page_file_mapping(page)->host;
 
 
 959	int		status = 0;
 960
 961	nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 962
 963	dprintk("NFS:       nfs_updatepage(%pD2 %d@%lld)\n",
 964		file, count, (long long)(page_file_offset(page) + offset));
 965
 966	if (nfs_can_extend_write(file, page, inode)) {
 967		count = max(count + offset, nfs_page_length(page));
 
 
 
 968		offset = 0;
 969	}
 970
 971	status = nfs_writepage_setup(ctx, page, offset, count);
 972	if (status < 0)
 973		nfs_set_pageerror(page);
 974	else
 975		__set_page_dirty_nobuffers(page);
 976
 977	dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
 978			status, (long long)i_size_read(inode));
 979	return status;
 980}
 981
 982static int flush_task_priority(int how)
 983{
 984	switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
 985		case FLUSH_HIGHPRI:
 986			return RPC_PRIORITY_HIGH;
 987		case FLUSH_LOWPRI:
 988			return RPC_PRIORITY_LOW;
 989	}
 990	return RPC_PRIORITY_NORMAL;
 991}
 992
 993int nfs_initiate_write(struct rpc_clnt *clnt,
 994		       struct nfs_write_data *data,
 995		       const struct rpc_call_ops *call_ops,
 996		       int how, int flags)
 997{
 998	struct inode *inode = data->header->inode;
 999	int priority = flush_task_priority(how);
1000	struct rpc_task *task;
1001	struct rpc_message msg = {
1002		.rpc_argp = &data->args,
1003		.rpc_resp = &data->res,
1004		.rpc_cred = data->header->cred,
1005	};
1006	struct rpc_task_setup task_setup_data = {
1007		.rpc_client = clnt,
1008		.task = &data->task,
1009		.rpc_message = &msg,
1010		.callback_ops = call_ops,
1011		.callback_data = data,
1012		.workqueue = nfsiod_workqueue,
1013		.flags = RPC_TASK_ASYNC | flags,
1014		.priority = priority,
1015	};
1016	int ret = 0;
1017
1018	/* Set up the initial task struct.  */
1019	NFS_PROTO(inode)->write_setup(data, &msg);
1020
1021	dprintk("NFS: %5u initiated write call "
1022		"(req %s/%llu, %u bytes @ offset %llu)\n",
1023		data->task.tk_pid,
1024		inode->i_sb->s_id,
1025		(unsigned long long)NFS_FILEID(inode),
1026		data->args.count,
1027		(unsigned long long)data->args.offset);
1028
1029	nfs4_state_protect_write(NFS_SERVER(inode)->nfs_client,
1030				 &task_setup_data.rpc_client, &msg, data);
1031
1032	task = rpc_run_task(&task_setup_data);
1033	if (IS_ERR(task)) {
1034		ret = PTR_ERR(task);
1035		goto out;
1036	}
1037	if (how & FLUSH_SYNC) {
1038		ret = rpc_wait_for_completion_task(task);
1039		if (ret == 0)
1040			ret = task->tk_status;
1041	}
1042	rpc_put_task(task);
1043out:
1044	return ret;
1045}
1046EXPORT_SYMBOL_GPL(nfs_initiate_write);
1047
1048/*
1049 * Set up the argument/result storage required for the RPC call.
1050 */
1051static void nfs_write_rpcsetup(struct nfs_write_data *data,
1052		unsigned int count, unsigned int offset,
1053		int how, struct nfs_commit_info *cinfo)
1054{
1055	struct nfs_page *req = data->header->req;
1056
1057	/* Set up the RPC argument and reply structs
1058	 * NB: take care not to mess about with data->commit et al. */
1059
1060	data->args.fh     = NFS_FH(data->header->inode);
1061	data->args.offset = req_offset(req) + offset;
1062	/* pnfs_set_layoutcommit needs this */
1063	data->mds_offset = data->args.offset;
1064	data->args.pgbase = req->wb_pgbase + offset;
1065	data->args.pages  = data->pages.pagevec;
1066	data->args.count  = count;
1067	data->args.context = get_nfs_open_context(req->wb_context);
1068	data->args.lock_context = req->wb_lock_context;
1069	data->args.stable  = NFS_UNSTABLE;
1070	switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
1071	case 0:
1072		break;
1073	case FLUSH_COND_STABLE:
1074		if (nfs_reqs_to_commit(cinfo))
1075			break;
1076	default:
1077		data->args.stable = NFS_FILE_SYNC;
1078	}
1079
1080	data->res.fattr   = &data->fattr;
1081	data->res.count   = count;
1082	data->res.verf    = &data->verf;
1083	nfs_fattr_init(&data->fattr);
1084}
1085
1086static int nfs_do_write(struct nfs_write_data *data,
1087		const struct rpc_call_ops *call_ops,
1088		int how)
1089{
1090	struct inode *inode = data->header->inode;
1091
1092	return nfs_initiate_write(NFS_CLIENT(inode), data, call_ops, how, 0);
1093}
1094
1095static int nfs_do_multiple_writes(struct list_head *head,
1096		const struct rpc_call_ops *call_ops,
1097		int how)
1098{
1099	struct nfs_write_data *data;
1100	int ret = 0;
1101
1102	while (!list_empty(head)) {
1103		int ret2;
1104
1105		data = list_first_entry(head, struct nfs_write_data, list);
1106		list_del_init(&data->list);
1107		
1108		ret2 = nfs_do_write(data, call_ops, how);
1109		 if (ret == 0)
1110			 ret = ret2;
1111	}
1112	return ret;
1113}
1114
1115/* If a nfs_flush_* function fails, it should remove reqs from @head and
1116 * call this on each, which will prepare them to be retried on next
1117 * writeback using standard nfs.
1118 */
1119static void nfs_redirty_request(struct nfs_page *req)
1120{
 
 
1121	nfs_mark_request_dirty(req);
1122	nfs_unlock_request(req);
1123	nfs_end_page_writeback(req->wb_page);
1124	nfs_release_request(req);
1125}
1126
1127static void nfs_async_write_error(struct list_head *head)
1128{
1129	struct nfs_page	*req;
1130
1131	while (!list_empty(head)) {
1132		req = nfs_list_entry(head->next);
1133		nfs_list_remove_request(req);
1134		nfs_redirty_request(req);
 
 
 
1135	}
1136}
1137
 
 
 
 
 
 
 
1138static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
 
1139	.error_cleanup = nfs_async_write_error,
1140	.completion = nfs_write_completion,
 
1141};
1142
1143static void nfs_flush_error(struct nfs_pageio_descriptor *desc,
1144		struct nfs_pgio_header *hdr)
1145{
1146	set_bit(NFS_IOHDR_REDO, &hdr->flags);
1147	while (!list_empty(&hdr->rpc_list)) {
1148		struct nfs_write_data *data = list_first_entry(&hdr->rpc_list,
1149				struct nfs_write_data, list);
1150		list_del(&data->list);
1151		nfs_writedata_release(data);
1152	}
1153	desc->pg_completion_ops->error_cleanup(&desc->pg_list);
1154}
1155
1156/*
1157 * Generate multiple small requests to write out a single
1158 * contiguous dirty area on one page.
1159 */
1160static int nfs_flush_multi(struct nfs_pageio_descriptor *desc,
1161			   struct nfs_pgio_header *hdr)
1162{
1163	struct nfs_page *req = hdr->req;
1164	struct page *page = req->wb_page;
1165	struct nfs_write_data *data;
1166	size_t wsize = desc->pg_bsize, nbytes;
1167	unsigned int offset;
1168	int requests = 0;
1169	struct nfs_commit_info cinfo;
1170
1171	nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
1172
1173	if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1174	    (desc->pg_moreio || nfs_reqs_to_commit(&cinfo) ||
1175	     desc->pg_count > wsize))
1176		desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1177
1178
1179	offset = 0;
1180	nbytes = desc->pg_count;
1181	do {
1182		size_t len = min(nbytes, wsize);
1183
1184		data = nfs_writedata_alloc(hdr, 1);
1185		if (!data) {
1186			nfs_flush_error(desc, hdr);
1187			return -ENOMEM;
1188		}
1189		data->pages.pagevec[0] = page;
1190		nfs_write_rpcsetup(data, len, offset, desc->pg_ioflags, &cinfo);
1191		list_add(&data->list, &hdr->rpc_list);
1192		requests++;
1193		nbytes -= len;
1194		offset += len;
1195	} while (nbytes != 0);
1196	nfs_list_remove_request(req);
1197	nfs_list_add_request(req, &hdr->pages);
1198	desc->pg_rpc_callops = &nfs_write_common_ops;
1199	return 0;
1200}
1201
1202/*
1203 * Create an RPC task for the given write request and kick it.
1204 * The page must have been locked by the caller.
1205 *
1206 * It may happen that the page we're passed is not marked dirty.
1207 * This is the case if nfs_updatepage detects a conflicting request
1208 * that has been written but not committed.
1209 */
1210static int nfs_flush_one(struct nfs_pageio_descriptor *desc,
1211			 struct nfs_pgio_header *hdr)
1212{
1213	struct nfs_page		*req;
1214	struct page		**pages;
1215	struct nfs_write_data	*data;
1216	struct list_head *head = &desc->pg_list;
1217	struct nfs_commit_info cinfo;
1218
1219	data = nfs_writedata_alloc(hdr, nfs_page_array_len(desc->pg_base,
1220							   desc->pg_count));
1221	if (!data) {
1222		nfs_flush_error(desc, hdr);
1223		return -ENOMEM;
1224	}
1225
1226	nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
1227	pages = data->pages.pagevec;
1228	while (!list_empty(head)) {
1229		req = nfs_list_entry(head->next);
1230		nfs_list_remove_request(req);
1231		nfs_list_add_request(req, &hdr->pages);
1232		*pages++ = req->wb_page;
1233	}
1234
1235	if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1236	    (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
1237		desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1238
1239	/* Set up the argument struct */
1240	nfs_write_rpcsetup(data, desc->pg_count, 0, desc->pg_ioflags, &cinfo);
1241	list_add(&data->list, &hdr->rpc_list);
1242	desc->pg_rpc_callops = &nfs_write_common_ops;
1243	return 0;
1244}
1245
1246int nfs_generic_flush(struct nfs_pageio_descriptor *desc,
1247		      struct nfs_pgio_header *hdr)
1248{
1249	if (desc->pg_bsize < PAGE_CACHE_SIZE)
1250		return nfs_flush_multi(desc, hdr);
1251	return nfs_flush_one(desc, hdr);
1252}
1253EXPORT_SYMBOL_GPL(nfs_generic_flush);
1254
1255static int nfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
1256{
1257	struct nfs_write_header *whdr;
1258	struct nfs_pgio_header *hdr;
1259	int ret;
1260
1261	whdr = nfs_writehdr_alloc();
1262	if (!whdr) {
1263		desc->pg_completion_ops->error_cleanup(&desc->pg_list);
1264		return -ENOMEM;
1265	}
1266	hdr = &whdr->header;
1267	nfs_pgheader_init(desc, hdr, nfs_writehdr_free);
1268	atomic_inc(&hdr->refcnt);
1269	ret = nfs_generic_flush(desc, hdr);
1270	if (ret == 0)
1271		ret = nfs_do_multiple_writes(&hdr->rpc_list,
1272					     desc->pg_rpc_callops,
1273					     desc->pg_ioflags);
1274	if (atomic_dec_and_test(&hdr->refcnt))
1275		hdr->completion_ops->completion(hdr);
1276	return ret;
1277}
1278
1279static const struct nfs_pageio_ops nfs_pageio_write_ops = {
1280	.pg_test = nfs_generic_pg_test,
1281	.pg_doio = nfs_generic_pg_writepages,
1282};
1283
1284void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1285			       struct inode *inode, int ioflags,
1286			       const struct nfs_pgio_completion_ops *compl_ops)
1287{
1288	nfs_pageio_init(pgio, inode, &nfs_pageio_write_ops, compl_ops,
1289				NFS_SERVER(inode)->wsize, ioflags);
1290}
1291EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
1292
1293void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1294{
1295	pgio->pg_ops = &nfs_pageio_write_ops;
1296	pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1297}
1298EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1299
1300
1301void nfs_write_prepare(struct rpc_task *task, void *calldata)
1302{
1303	struct nfs_write_data *data = calldata;
1304	int err;
1305	err = NFS_PROTO(data->header->inode)->write_rpc_prepare(task, data);
1306	if (err)
1307		rpc_exit(task, err);
1308}
1309
1310void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1311{
1312	struct nfs_commit_data *data = calldata;
1313
1314	NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1315}
1316
1317/*
1318 * Handle a write reply that flushes a whole page.
1319 *
1320 * FIXME: There is an inherent race with invalidate_inode_pages and
1321 *	  writebacks since the page->count is kept > 1 for as long
1322 *	  as the page has a write request pending.
1323 */
1324static void nfs_writeback_done_common(struct rpc_task *task, void *calldata)
1325{
1326	struct nfs_write_data	*data = calldata;
 
 
 
 
 
 
 
 
 
 
 
 
1327
1328	nfs_writeback_done(task, data);
 
 
 
1329}
1330
1331static void nfs_writeback_release_common(void *calldata)
 
1332{
1333	struct nfs_write_data	*data = calldata;
1334	struct nfs_pgio_header *hdr = data->header;
1335	int status = data->task.tk_status;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1336
1337	if ((status >= 0) && nfs_write_need_commit(data)) {
1338		spin_lock(&hdr->lock);
1339		if (test_bit(NFS_IOHDR_NEED_RESCHED, &hdr->flags))
1340			; /* Do nothing */
1341		else if (!test_and_set_bit(NFS_IOHDR_NEED_COMMIT, &hdr->flags))
1342			memcpy(hdr->verf, &data->verf, sizeof(*hdr->verf));
1343		else if (memcmp(hdr->verf, &data->verf, sizeof(*hdr->verf)))
1344			set_bit(NFS_IOHDR_NEED_RESCHED, &hdr->flags);
1345		spin_unlock(&hdr->lock);
1346	}
1347	nfs_writedata_release(data);
1348}
1349
1350static const struct rpc_call_ops nfs_write_common_ops = {
1351	.rpc_call_prepare = nfs_write_prepare,
1352	.rpc_call_done = nfs_writeback_done_common,
1353	.rpc_release = nfs_writeback_release_common,
1354};
1355
 
 
 
 
 
 
1356
1357/*
1358 * This function is called when the WRITE call is complete.
1359 */
1360void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
 
 
1361{
1362	struct nfs_writeargs	*argp = &data->args;
1363	struct nfs_writeres	*resp = &data->res;
1364	struct inode		*inode = data->header->inode;
1365	int status;
1366
1367	dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1368		task->tk_pid, task->tk_status);
1369
1370	/*
1371	 * ->write_done will attempt to use post-op attributes to detect
1372	 * conflicting writes by other clients.  A strict interpretation
1373	 * of close-to-open would allow us to continue caching even if
1374	 * another writer had changed the file, but some applications
1375	 * depend on tighter cache coherency when writing.
1376	 */
1377	status = NFS_PROTO(inode)->write_done(task, data);
1378	if (status != 0)
1379		return;
1380	nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1381
1382#if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4)
1383	if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
 
 
 
1384		/* We tried a write call, but the server did not
1385		 * commit data to stable storage even though we
1386		 * requested it.
1387		 * Note: There is a known bug in Tru64 < 5.0 in which
1388		 *	 the server reports NFS_DATA_SYNC, but performs
1389		 *	 NFS_FILE_SYNC. We therefore implement this checking
1390		 *	 as a dprintk() in order to avoid filling syslog.
1391		 */
1392		static unsigned long    complain;
1393
1394		/* Note this will print the MDS for a DS write */
1395		if (time_before(complain, jiffies)) {
1396			dprintk("NFS:       faulty NFS server %s:"
1397				" (committed = %d) != (stable = %d)\n",
1398				NFS_SERVER(inode)->nfs_client->cl_hostname,
1399				resp->verf->committed, argp->stable);
1400			complain = jiffies + 300 * HZ;
1401		}
1402	}
1403#endif
1404	if (task->tk_status < 0)
1405		nfs_set_pgio_error(data->header, task->tk_status, argp->offset);
1406	else if (resp->count < argp->count) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1407		static unsigned long    complain;
1408
1409		/* This a short write! */
1410		nfs_inc_stats(inode, NFSIOS_SHORTWRITE);
1411
1412		/* Has the server at least made some progress? */
1413		if (resp->count == 0) {
1414			if (time_before(complain, jiffies)) {
1415				printk(KERN_WARNING
1416				       "NFS: Server wrote zero bytes, expected %u.\n",
1417				       argp->count);
1418				complain = jiffies + 300 * HZ;
1419			}
1420			nfs_set_pgio_error(data->header, -EIO, argp->offset);
1421			task->tk_status = -EIO;
1422			return;
1423		}
 
 
 
 
 
 
 
1424		/* Was this an NFSv2 write or an NFSv3 stable write? */
1425		if (resp->verf->committed != NFS_UNSTABLE) {
1426			/* Resend from where the server left off */
1427			data->mds_offset += resp->count;
1428			argp->offset += resp->count;
1429			argp->pgbase += resp->count;
1430			argp->count -= resp->count;
1431		} else {
1432			/* Resend as a stable write in order to avoid
1433			 * headaches in the case of a server crash.
1434			 */
1435			argp->stable = NFS_FILE_SYNC;
1436		}
 
 
1437		rpc_restart_call_prepare(task);
1438	}
1439}
1440
1441
1442#if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4)
1443static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait)
1444{
1445	int ret;
 
 
1446
1447	if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags))
1448		return 1;
1449	if (!may_wait)
1450		return 0;
1451	ret = out_of_line_wait_on_bit_lock(&nfsi->flags,
1452				NFS_INO_COMMIT,
1453				nfs_wait_bit_killable,
1454				TASK_KILLABLE);
1455	return (ret < 0) ? ret : 1;
1456}
1457
1458static void nfs_commit_clear_lock(struct nfs_inode *nfsi)
1459{
1460	clear_bit(NFS_INO_COMMIT, &nfsi->flags);
1461	smp_mb__after_clear_bit();
1462	wake_up_bit(&nfsi->flags, NFS_INO_COMMIT);
1463}
1464
1465void nfs_commitdata_release(struct nfs_commit_data *data)
1466{
1467	put_nfs_open_context(data->context);
1468	nfs_commit_free(data);
1469}
1470EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1471
1472int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
 
1473			const struct rpc_call_ops *call_ops,
1474			int how, int flags)
1475{
1476	struct rpc_task *task;
1477	int priority = flush_task_priority(how);
1478	struct rpc_message msg = {
1479		.rpc_argp = &data->args,
1480		.rpc_resp = &data->res,
1481		.rpc_cred = data->cred,
1482	};
1483	struct rpc_task_setup task_setup_data = {
1484		.task = &data->task,
1485		.rpc_client = clnt,
1486		.rpc_message = &msg,
1487		.callback_ops = call_ops,
1488		.callback_data = data,
1489		.workqueue = nfsiod_workqueue,
1490		.flags = RPC_TASK_ASYNC | flags,
1491		.priority = priority,
1492	};
1493	/* Set up the initial task struct.  */
1494	NFS_PROTO(data->inode)->commit_setup(data, &msg);
1495
1496	dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1497
1498	nfs4_state_protect(NFS_SERVER(data->inode)->nfs_client,
1499		NFS_SP4_MACH_CRED_COMMIT, &task_setup_data.rpc_client, &msg);
1500
1501	task = rpc_run_task(&task_setup_data);
1502	if (IS_ERR(task))
1503		return PTR_ERR(task);
1504	if (how & FLUSH_SYNC)
1505		rpc_wait_for_completion_task(task);
1506	rpc_put_task(task);
1507	return 0;
1508}
1509EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1510
 
 
 
 
 
 
 
 
 
 
 
 
1511/*
1512 * Set up the argument/result storage required for the RPC call.
1513 */
1514void nfs_init_commit(struct nfs_commit_data *data,
1515		     struct list_head *head,
1516		     struct pnfs_layout_segment *lseg,
1517		     struct nfs_commit_info *cinfo)
1518{
1519	struct nfs_page *first = nfs_list_entry(head->next);
1520	struct inode *inode = first->wb_context->dentry->d_inode;
 
1521
1522	/* Set up the RPC argument and reply structs
1523	 * NB: take care not to mess about with data->commit et al. */
1524
1525	list_splice_init(head, &data->pages);
 
 
 
 
 
1526
1527	data->inode	  = inode;
1528	data->cred	  = first->wb_context->cred;
1529	data->lseg	  = lseg; /* reference transferred */
 
 
 
1530	data->mds_ops     = &nfs_commit_ops;
1531	data->completion_ops = cinfo->completion_ops;
1532	data->dreq	  = cinfo->dreq;
1533
1534	data->args.fh     = NFS_FH(data->inode);
1535	/* Note: we always request a commit of the entire inode */
1536	data->args.offset = 0;
1537	data->args.count  = 0;
1538	data->context     = get_nfs_open_context(first->wb_context);
1539	data->res.fattr   = &data->fattr;
1540	data->res.verf    = &data->verf;
1541	nfs_fattr_init(&data->fattr);
1542}
1543EXPORT_SYMBOL_GPL(nfs_init_commit);
1544
1545void nfs_retry_commit(struct list_head *page_list,
1546		      struct pnfs_layout_segment *lseg,
1547		      struct nfs_commit_info *cinfo)
 
1548{
1549	struct nfs_page *req;
1550
1551	while (!list_empty(page_list)) {
1552		req = nfs_list_entry(page_list->next);
1553		nfs_list_remove_request(req);
1554		nfs_mark_request_commit(req, lseg, cinfo);
1555		if (!cinfo->dreq) {
1556			dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1557			dec_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
1558				     BDI_RECLAIMABLE);
1559		}
1560		nfs_unlock_and_release_request(req);
1561	}
1562}
1563EXPORT_SYMBOL_GPL(nfs_retry_commit);
1564
 
 
 
 
 
 
 
1565/*
1566 * Commit dirty pages
1567 */
1568static int
1569nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1570		struct nfs_commit_info *cinfo)
1571{
1572	struct nfs_commit_data	*data;
 
1573
1574	data = nfs_commitdata_alloc();
 
 
1575
1576	if (!data)
1577		goto out_bad;
1578
1579	/* Set up the argument struct */
1580	nfs_init_commit(data, head, NULL, cinfo);
1581	atomic_inc(&cinfo->mds->rpcs_out);
1582	return nfs_initiate_commit(NFS_CLIENT(inode), data, data->mds_ops,
1583				   how, 0);
1584 out_bad:
1585	nfs_retry_commit(head, NULL, cinfo);
1586	cinfo->completion_ops->error_cleanup(NFS_I(inode));
1587	return -ENOMEM;
1588}
1589
1590/*
1591 * COMMIT call returned
1592 */
1593static void nfs_commit_done(struct rpc_task *task, void *calldata)
1594{
1595	struct nfs_commit_data	*data = calldata;
1596
1597        dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1598                                task->tk_pid, task->tk_status);
1599
1600	/* Call the NFS version-specific code */
1601	NFS_PROTO(data->inode)->commit_done(task, data);
 
1602}
1603
1604static void nfs_commit_release_pages(struct nfs_commit_data *data)
1605{
 
1606	struct nfs_page	*req;
1607	int status = data->task.tk_status;
1608	struct nfs_commit_info cinfo;
 
1609
1610	while (!list_empty(&data->pages)) {
1611		req = nfs_list_entry(data->pages.next);
1612		nfs_list_remove_request(req);
1613		nfs_clear_page_commit(req->wb_page);
 
1614
1615		dprintk("NFS:       commit (%s/%llu %d@%lld)",
1616			req->wb_context->dentry->d_sb->s_id,
1617			(unsigned long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1618			req->wb_bytes,
1619			(long long)req_offset(req));
1620		if (status < 0) {
1621			nfs_context_set_write_error(req->wb_context, status);
1622			nfs_inode_remove_request(req);
1623			dprintk(", error = %d\n", status);
 
 
 
1624			goto next;
1625		}
1626
1627		/* Okay, COMMIT succeeded, apparently. Check the verifier
1628		 * returned by the server against all stored verfs. */
1629		if (!memcmp(&req->wb_verf, &data->verf.verifier, sizeof(req->wb_verf))) {
1630			/* We have a match */
1631			nfs_inode_remove_request(req);
1632			dprintk(" OK\n");
 
1633			goto next;
1634		}
1635		/* We have a mismatch. Write the page again */
1636		dprintk(" mismatch\n");
1637		nfs_mark_request_dirty(req);
1638		set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags);
1639	next:
1640		nfs_unlock_and_release_request(req);
 
 
1641	}
 
 
 
 
1642	nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1643	if (atomic_dec_and_test(&cinfo.mds->rpcs_out))
1644		nfs_commit_clear_lock(NFS_I(data->inode));
1645}
1646
1647static void nfs_commit_release(void *calldata)
1648{
1649	struct nfs_commit_data *data = calldata;
1650
1651	data->completion_ops->completion(data);
1652	nfs_commitdata_release(calldata);
1653}
1654
1655static const struct rpc_call_ops nfs_commit_ops = {
1656	.rpc_call_prepare = nfs_commit_prepare,
1657	.rpc_call_done = nfs_commit_done,
1658	.rpc_release = nfs_commit_release,
1659};
1660
1661static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1662	.completion = nfs_commit_release_pages,
1663	.error_cleanup = nfs_commit_clear_lock,
1664};
1665
1666int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1667			    int how, struct nfs_commit_info *cinfo)
1668{
1669	int status;
1670
1671	status = pnfs_commit_list(inode, head, how, cinfo);
1672	if (status == PNFS_NOT_ATTEMPTED)
1673		status = nfs_commit_list(inode, head, how, cinfo);
1674	return status;
1675}
1676
1677int nfs_commit_inode(struct inode *inode, int how)
 
1678{
1679	LIST_HEAD(head);
1680	struct nfs_commit_info cinfo;
1681	int may_wait = how & FLUSH_SYNC;
1682	int res;
1683
1684	res = nfs_commit_set_lock(NFS_I(inode), may_wait);
1685	if (res <= 0)
1686		goto out_mark_dirty;
1687	nfs_init_cinfo_from_inode(&cinfo, inode);
1688	res = nfs_scan_commit(inode, &head, &cinfo);
1689	if (res) {
1690		int error;
1691
1692		error = nfs_generic_commit_list(inode, &head, how, &cinfo);
1693		if (error < 0)
1694			return error;
1695		if (!may_wait)
1696			goto out_mark_dirty;
1697		error = wait_on_bit(&NFS_I(inode)->flags,
1698				NFS_INO_COMMIT,
1699				nfs_wait_bit_killable,
1700				TASK_KILLABLE);
1701		if (error < 0)
1702			return error;
1703	} else
1704		nfs_commit_clear_lock(NFS_I(inode));
1705	return res;
1706	/* Note: If we exit without ensuring that the commit is complete,
1707	 * we must mark the inode as dirty. Otherwise, future calls to
1708	 * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
1709	 * that the data is on the disk.
1710	 */
1711out_mark_dirty:
1712	__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1713	return res;
1714}
1715
1716static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
 
 
 
 
 
 
1717{
1718	struct nfs_inode *nfsi = NFS_I(inode);
1719	int flags = FLUSH_SYNC;
1720	int ret = 0;
1721
1722	/* no commits means nothing needs to be done */
1723	if (!nfsi->commit_info.ncommit)
1724		return ret;
1725
1726	if (wbc->sync_mode == WB_SYNC_NONE) {
 
 
 
 
1727		/* Don't commit yet if this is a non-blocking flush and there
1728		 * are a lot of outstanding writes for this mapping.
1729		 */
1730		if (nfsi->commit_info.ncommit <= (nfsi->npages >> 1))
1731			goto out_mark_dirty;
1732
1733		/* don't wait for the COMMIT response */
1734		flags = 0;
1735	}
1736
1737	ret = nfs_commit_inode(inode, flags);
1738	if (ret >= 0) {
1739		if (wbc->sync_mode == WB_SYNC_NONE) {
1740			if (ret < wbc->nr_to_write)
1741				wbc->nr_to_write -= ret;
1742			else
1743				wbc->nr_to_write = 0;
1744		}
1745		return 0;
1746	}
1747out_mark_dirty:
1748	__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1749	return ret;
1750}
1751#else
1752static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1753{
1754	return 0;
1755}
1756#endif
1757
1758int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 
 
 
 
 
 
 
1759{
1760	return nfs_commit_unstable_pages(inode, wbc);
 
 
 
 
 
1761}
1762EXPORT_SYMBOL_GPL(nfs_write_inode);
1763
1764/*
1765 * flush the inode to disk.
1766 */
1767int nfs_wb_all(struct inode *inode)
1768{
1769	struct writeback_control wbc = {
1770		.sync_mode = WB_SYNC_ALL,
1771		.nr_to_write = LONG_MAX,
1772		.range_start = 0,
1773		.range_end = LLONG_MAX,
1774	};
1775	int ret;
1776
1777	trace_nfs_writeback_inode_enter(inode);
1778
1779	ret = sync_inode(inode, &wbc);
 
 
 
 
 
 
 
1780
 
1781	trace_nfs_writeback_inode_exit(inode, ret);
1782	return ret;
1783}
1784EXPORT_SYMBOL_GPL(nfs_wb_all);
1785
1786int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1787{
1788	struct nfs_page *req;
1789	int ret = 0;
1790
1791	for (;;) {
1792		wait_on_page_writeback(page);
1793		req = nfs_page_find_request(page);
1794		if (req == NULL)
1795			break;
1796		if (nfs_lock_request(req)) {
1797			nfs_clear_request_commit(req);
1798			nfs_inode_remove_request(req);
1799			/*
1800			 * In case nfs_inode_remove_request has marked the
1801			 * page as being dirty
1802			 */
1803			cancel_dirty_page(page, PAGE_CACHE_SIZE);
1804			nfs_unlock_and_release_request(req);
1805			break;
1806		}
1807		ret = nfs_wait_on_request(req);
1808		nfs_release_request(req);
1809		if (ret < 0)
1810			break;
1811	}
 
1812	return ret;
1813}
1814
1815/*
1816 * Write back all requests on one page - we do this before reading it.
1817 */
1818int nfs_wb_page(struct inode *inode, struct page *page)
1819{
1820	loff_t range_start = page_file_offset(page);
1821	loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1822	struct writeback_control wbc = {
1823		.sync_mode = WB_SYNC_ALL,
1824		.nr_to_write = 0,
1825		.range_start = range_start,
1826		.range_end = range_end,
1827	};
1828	int ret;
1829
1830	trace_nfs_writeback_page_enter(inode);
1831
1832	for (;;) {
1833		wait_on_page_writeback(page);
1834		if (clear_page_dirty_for_io(page)) {
1835			ret = nfs_writepage_locked(page, &wbc);
1836			if (ret < 0)
1837				goto out_error;
1838			continue;
1839		}
1840		ret = 0;
1841		if (!PagePrivate(page))
1842			break;
1843		ret = nfs_commit_inode(inode, FLUSH_SYNC);
1844		if (ret < 0)
1845			goto out_error;
1846	}
1847out_error:
1848	trace_nfs_writeback_page_exit(inode, ret);
1849	return ret;
1850}
1851
1852#ifdef CONFIG_MIGRATION
1853int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
1854		struct page *page, enum migrate_mode mode)
1855{
1856	/*
1857	 * If PagePrivate is set, then the page is currently associated with
1858	 * an in-progress read or write request. Don't try to migrate it.
1859	 *
1860	 * FIXME: we could do this in principle, but we'll need a way to ensure
1861	 *        that we can safely release the inode reference while holding
1862	 *        the page lock.
1863	 */
1864	if (PagePrivate(page))
1865		return -EBUSY;
1866
1867	if (!nfs_fscache_release_page(page, GFP_KERNEL))
1868		return -EBUSY;
1869
1870	return migrate_page(mapping, newpage, page, mode);
1871}
1872#endif
1873
1874int __init nfs_init_writepagecache(void)
1875{
1876	nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1877					     sizeof(struct nfs_write_header),
1878					     0, SLAB_HWCACHE_ALIGN,
1879					     NULL);
1880	if (nfs_wdata_cachep == NULL)
1881		return -ENOMEM;
1882
1883	nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1884						     nfs_wdata_cachep);
1885	if (nfs_wdata_mempool == NULL)
1886		goto out_destroy_write_cache;
1887
1888	nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
1889					     sizeof(struct nfs_commit_data),
1890					     0, SLAB_HWCACHE_ALIGN,
1891					     NULL);
1892	if (nfs_cdata_cachep == NULL)
1893		goto out_destroy_write_mempool;
1894
1895	nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1896						      nfs_cdata_cachep);
1897	if (nfs_commit_mempool == NULL)
1898		goto out_destroy_commit_cache;
1899
1900	/*
1901	 * NFS congestion size, scale with available memory.
1902	 *
1903	 *  64MB:    8192k
1904	 * 128MB:   11585k
1905	 * 256MB:   16384k
1906	 * 512MB:   23170k
1907	 *   1GB:   32768k
1908	 *   2GB:   46340k
1909	 *   4GB:   65536k
1910	 *   8GB:   92681k
1911	 *  16GB:  131072k
1912	 *
1913	 * This allows larger machines to have larger/more transfers.
1914	 * Limit the default to 256M
1915	 */
1916	nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1917	if (nfs_congestion_kb > 256*1024)
1918		nfs_congestion_kb = 256*1024;
1919
1920	return 0;
1921
1922out_destroy_commit_cache:
1923	kmem_cache_destroy(nfs_cdata_cachep);
1924out_destroy_write_mempool:
1925	mempool_destroy(nfs_wdata_mempool);
1926out_destroy_write_cache:
1927	kmem_cache_destroy(nfs_wdata_cachep);
1928	return -ENOMEM;
1929}
1930
1931void nfs_destroy_writepagecache(void)
1932{
1933	mempool_destroy(nfs_commit_mempool);
1934	kmem_cache_destroy(nfs_cdata_cachep);
1935	mempool_destroy(nfs_wdata_mempool);
1936	kmem_cache_destroy(nfs_wdata_cachep);
1937}
1938