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#include <linux/freezer.h>
  25#include <linux/wait.h>
  26#include <linux/iversion.h>
  27
  28#include <linux/uaccess.h>
 
  29
  30#include "delegation.h"
  31#include "internal.h"
  32#include "iostat.h"
  33#include "nfs4_fs.h"
  34#include "fscache.h"
  35#include "pnfs.h"
  36
  37#include "nfstrace.h"
  38
  39#define NFSDBG_FACILITY		NFSDBG_PAGECACHE
  40
  41#define MIN_POOL_WRITE		(32)
  42#define MIN_POOL_COMMIT		(4)
  43
  44struct nfs_io_completion {
  45	void (*complete)(void *data);
  46	void *data;
  47	struct kref refcount;
  48};
  49
  50/*
  51 * Local function declarations
  52 */
  53static void nfs_redirty_request(struct nfs_page *req);
  54static const struct rpc_call_ops nfs_commit_ops;
  55static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
  56static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
  57static const struct nfs_rw_ops nfs_rw_write_ops;
 
  58static void nfs_clear_request_commit(struct nfs_page *req);
  59static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
  60				      struct inode *inode);
  61static struct nfs_page *
  62nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
  63						struct page *page);
  64
  65static struct kmem_cache *nfs_wdata_cachep;
  66static mempool_t *nfs_wdata_mempool;
  67static struct kmem_cache *nfs_cdata_cachep;
  68static mempool_t *nfs_commit_mempool;
  69
  70struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail)
  71{
  72	struct nfs_commit_data *p;
  73
  74	if (never_fail)
  75		p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);
  76	else {
  77		/* It is OK to do some reclaim, not no safe to wait
  78		 * for anything to be returned to the pool.
  79		 * mempool_alloc() cannot handle that particular combination,
  80		 * so we need two separate attempts.
  81		 */
  82		p = mempool_alloc(nfs_commit_mempool, GFP_NOWAIT);
  83		if (!p)
  84			p = kmem_cache_alloc(nfs_cdata_cachep, GFP_NOIO |
  85					     __GFP_NOWARN | __GFP_NORETRY);
  86		if (!p)
  87			return NULL;
  88	}
  89
  90	memset(p, 0, sizeof(*p));
  91	INIT_LIST_HEAD(&p->pages);
  92	return p;
  93}
  94EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
  95
  96void nfs_commit_free(struct nfs_commit_data *p)
  97{
  98	mempool_free(p, nfs_commit_mempool);
  99}
 100EXPORT_SYMBOL_GPL(nfs_commit_free);
 101
 102static struct nfs_pgio_header *nfs_writehdr_alloc(void)
 103{
 104	struct nfs_pgio_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);
 105
 106	memset(p, 0, sizeof(*p));
 107	p->rw_mode = FMODE_WRITE;
 108	return p;
 109}
 110
 111static void nfs_writehdr_free(struct nfs_pgio_header *hdr)
 112{
 113	mempool_free(hdr, nfs_wdata_mempool);
 114}
 115
 116static struct nfs_io_completion *nfs_io_completion_alloc(gfp_t gfp_flags)
 117{
 118	return kmalloc(sizeof(struct nfs_io_completion), gfp_flags);
 119}
 120
 121static void nfs_io_completion_init(struct nfs_io_completion *ioc,
 122		void (*complete)(void *), void *data)
 123{
 124	ioc->complete = complete;
 125	ioc->data = data;
 126	kref_init(&ioc->refcount);
 127}
 128
 129static void nfs_io_completion_release(struct kref *kref)
 130{
 131	struct nfs_io_completion *ioc = container_of(kref,
 132			struct nfs_io_completion, refcount);
 133	ioc->complete(ioc->data);
 134	kfree(ioc);
 135}
 136
 137static void nfs_io_completion_get(struct nfs_io_completion *ioc)
 138{
 139	if (ioc != NULL)
 140		kref_get(&ioc->refcount);
 141}
 142
 143static void nfs_io_completion_put(struct nfs_io_completion *ioc)
 144{
 145	if (ioc != NULL)
 146		kref_put(&ioc->refcount, nfs_io_completion_release);
 147}
 148
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 149static struct nfs_page *
 150nfs_page_private_request(struct page *page)
 151{
 152	if (!PagePrivate(page))
 153		return NULL;
 154	return (struct nfs_page *)page_private(page);
 155}
 156
 157/*
 158 * nfs_page_find_head_request_locked - find head request associated with @page
 159 *
 160 * must be called while holding the inode lock.
 161 *
 162 * returns matching head request with reference held, or NULL if not found.
 163 */
 164static struct nfs_page *
 165nfs_page_find_private_request(struct page *page)
 166{
 167	struct address_space *mapping = page_file_mapping(page);
 168	struct nfs_page *req;
 169
 170	if (!PagePrivate(page))
 171		return NULL;
 172	spin_lock(&mapping->private_lock);
 173	req = nfs_page_private_request(page);
 174	if (req) {
 175		WARN_ON_ONCE(req->wb_head != req);
 176		kref_get(&req->wb_kref);
 177	}
 178	spin_unlock(&mapping->private_lock);
 179	return req;
 180}
 181
 182static struct nfs_page *
 183nfs_page_find_swap_request(struct page *page)
 184{
 185	struct inode *inode = page_file_mapping(page)->host;
 186	struct nfs_inode *nfsi = NFS_I(inode);
 187	struct nfs_page *req = NULL;
 188	if (!PageSwapCache(page))
 189		return NULL;
 190	mutex_lock(&nfsi->commit_mutex);
 191	if (PageSwapCache(page)) {
 192		req = nfs_page_search_commits_for_head_request_locked(nfsi,
 193			page);
 194		if (req) {
 195			WARN_ON_ONCE(req->wb_head != req);
 196			kref_get(&req->wb_kref);
 197		}
 198	}
 199	mutex_unlock(&nfsi->commit_mutex);
 200	return req;
 201}
 202
 203/*
 204 * nfs_page_find_head_request - find head request associated with @page
 205 *
 206 * returns matching head request with reference held, or NULL if not found.
 207 */
 208static struct nfs_page *nfs_page_find_head_request(struct page *page)
 209{
 210	struct nfs_page *req;
 211
 212	req = nfs_page_find_private_request(page);
 213	if (!req)
 214		req = nfs_page_find_swap_request(page);
 215	return req;
 216}
 217
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 218/* Adjust the file length if we're writing beyond the end */
 219static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
 220{
 221	struct inode *inode = page_file_mapping(page)->host;
 222	loff_t end, i_size;
 223	pgoff_t end_index;
 224
 225	spin_lock(&inode->i_lock);
 226	i_size = i_size_read(inode);
 227	end_index = (i_size - 1) >> PAGE_SHIFT;
 228	if (i_size > 0 && page_index(page) < end_index)
 229		goto out;
 230	end = page_file_offset(page) + ((loff_t)offset+count);
 231	if (i_size >= end)
 232		goto out;
 233	i_size_write(inode, end);
 234	NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;
 235	nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 236out:
 237	spin_unlock(&inode->i_lock);
 238}
 239
 240/* A writeback failed: mark the page as bad, and invalidate the page cache */
 241static void nfs_set_pageerror(struct page *page)
 
 
 
 
 
 
 
 
 
 
 
 
 
 242{
 243	nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page));
 
 
 
 
 244}
 245
 246/*
 247 * nfs_page_group_search_locked
 248 * @head - head request of page group
 249 * @page_offset - offset into page
 250 *
 251 * Search page group with head @head to find a request that contains the
 252 * page offset @page_offset.
 253 *
 254 * Returns a pointer to the first matching nfs request, or NULL if no
 255 * match is found.
 256 *
 257 * Must be called with the page group lock held
 258 */
 259static struct nfs_page *
 260nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset)
 261{
 262	struct nfs_page *req;
 263
 264	req = head;
 265	do {
 266		if (page_offset >= req->wb_pgbase &&
 267		    page_offset < (req->wb_pgbase + req->wb_bytes))
 268			return req;
 269
 270		req = req->wb_this_page;
 271	} while (req != head);
 272
 273	return NULL;
 274}
 275
 276/*
 277 * nfs_page_group_covers_page
 278 * @head - head request of page group
 279 *
 280 * Return true if the page group with head @head covers the whole page,
 281 * returns false otherwise
 282 */
 283static bool nfs_page_group_covers_page(struct nfs_page *req)
 284{
 285	struct nfs_page *tmp;
 286	unsigned int pos = 0;
 287	unsigned int len = nfs_page_length(req->wb_page);
 288
 289	nfs_page_group_lock(req);
 290
 291	for (;;) {
 292		tmp = nfs_page_group_search_locked(req->wb_head, pos);
 293		if (!tmp)
 294			break;
 295		pos = tmp->wb_pgbase + tmp->wb_bytes;
 296	}
 297
 298	nfs_page_group_unlock(req);
 299	return pos >= len;
 300}
 301
 302/* We can set the PG_uptodate flag if we see that a write request
 303 * covers the full page.
 304 */
 305static void nfs_mark_uptodate(struct nfs_page *req)
 306{
 307	if (PageUptodate(req->wb_page))
 308		return;
 309	if (!nfs_page_group_covers_page(req))
 310		return;
 311	SetPageUptodate(req->wb_page);
 312}
 313
 314static int wb_priority(struct writeback_control *wbc)
 315{
 316	int ret = 0;
 317
 318	if (wbc->sync_mode == WB_SYNC_ALL)
 319		ret = FLUSH_COND_STABLE;
 320	return ret;
 321}
 322
 323/*
 324 * NFS congestion control
 325 */
 326
 327int nfs_congestion_kb;
 328
 329#define NFS_CONGESTION_ON_THRESH 	(nfs_congestion_kb >> (PAGE_SHIFT-10))
 330#define NFS_CONGESTION_OFF_THRESH	\
 331	(NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 332
 333static void nfs_set_page_writeback(struct page *page)
 334{
 335	struct inode *inode = page_file_mapping(page)->host;
 336	struct nfs_server *nfss = NFS_SERVER(inode);
 337	int ret = test_set_page_writeback(page);
 338
 339	WARN_ON_ONCE(ret != 0);
 340
 341	if (atomic_long_inc_return(&nfss->writeback) >
 342			NFS_CONGESTION_ON_THRESH)
 343		set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 344}
 345
 346static void nfs_end_page_writeback(struct nfs_page *req)
 347{
 348	struct inode *inode = page_file_mapping(req->wb_page)->host;
 349	struct nfs_server *nfss = NFS_SERVER(inode);
 350	bool is_done;
 351
 352	is_done = nfs_page_group_sync_on_bit(req, PG_WB_END);
 353	nfs_unlock_request(req);
 354	if (!is_done)
 355		return;
 356
 357	end_page_writeback(req->wb_page);
 358	if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
 359		clear_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 360}
 361
 362/*
 363 * nfs_unroll_locks_and_wait -  unlock all newly locked reqs and wait on @req
 364 *
 365 * this is a helper function for nfs_lock_and_join_requests
 366 *
 367 * @inode - inode associated with request page group, must be holding inode lock
 368 * @head  - head request of page group, must be holding head lock
 369 * @req   - request that couldn't lock and needs to wait on the req bit lock
 370 *
 371 * NOTE: this must be called holding page_group bit lock
 372 *       which will be released before returning.
 373 *
 374 * returns 0 on success, < 0 on error.
 375 */
 376static void
 377nfs_unroll_locks(struct inode *inode, struct nfs_page *head,
 378			  struct nfs_page *req)
 379{
 380	struct nfs_page *tmp;
 381
 382	/* relinquish all the locks successfully grabbed this run */
 383	for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {
 384		if (!kref_read(&tmp->wb_kref))
 385			continue;
 386		nfs_unlock_and_release_request(tmp);
 387	}
 388}
 389
 390/*
 391 * nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests
 392 *
 393 * @destroy_list - request list (using wb_this_page) terminated by @old_head
 394 * @old_head - the old head of the list
 395 *
 396 * All subrequests must be locked and removed from all lists, so at this point
 397 * they are only "active" in this function, and possibly in nfs_wait_on_request
 398 * with a reference held by some other context.
 399 */
 400static void
 401nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
 402				 struct nfs_page *old_head,
 403				 struct inode *inode)
 404{
 405	while (destroy_list) {
 406		struct nfs_page *subreq = destroy_list;
 407
 408		destroy_list = (subreq->wb_this_page == old_head) ?
 409				   NULL : subreq->wb_this_page;
 410
 
 
 411		WARN_ON_ONCE(old_head != subreq->wb_head);
 412
 413		/* make sure old group is not used */
 414		subreq->wb_this_page = subreq;
 
 415
 416		clear_bit(PG_REMOVE, &subreq->wb_flags);
 417
 418		/* Note: races with nfs_page_group_destroy() */
 419		if (!kref_read(&subreq->wb_kref)) {
 420			/* Check if we raced with nfs_page_group_destroy() */
 421			if (test_and_clear_bit(PG_TEARDOWN, &subreq->wb_flags))
 
 422				nfs_free_request(subreq);
 
 
 423			continue;
 424		}
 
 425
 426		subreq->wb_head = subreq;
 427
 428		if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) {
 429			nfs_release_request(subreq);
 430			atomic_long_dec(&NFS_I(inode)->nrequests);
 431		}
 432
 433		/* subreq is now totally disconnected from page group or any
 434		 * write / commit lists. last chance to wake any waiters */
 435		nfs_unlock_and_release_request(subreq);
 436	}
 437}
 438
 439/*
 440 * nfs_lock_and_join_requests - join all subreqs to the head req and return
 441 *                              a locked reference, cancelling any pending
 442 *                              operations for this page.
 443 *
 444 * @page - the page used to lookup the "page group" of nfs_page structures
 445 *
 446 * This function joins all sub requests to the head request by first
 447 * locking all requests in the group, cancelling any pending operations
 448 * and finally updating the head request to cover the whole range covered by
 449 * the (former) group.  All subrequests are removed from any write or commit
 450 * lists, unlinked from the group and destroyed.
 451 *
 452 * Returns a locked, referenced pointer to the head request - which after
 453 * this call is guaranteed to be the only request associated with the page.
 454 * Returns NULL if no requests are found for @page, or a ERR_PTR if an
 455 * error was encountered.
 456 */
 457static struct nfs_page *
 458nfs_lock_and_join_requests(struct page *page)
 459{
 460	struct inode *inode = page_file_mapping(page)->host;
 461	struct nfs_page *head, *subreq;
 462	struct nfs_page *destroy_list = NULL;
 463	unsigned int total_bytes;
 464	int ret;
 465
 466try_again:
 467	/*
 468	 * A reference is taken only on the head request which acts as a
 469	 * reference to the whole page group - the group will not be destroyed
 470	 * until the head reference is released.
 471	 */
 472	head = nfs_page_find_head_request(page);
 473	if (!head)
 474		return NULL;
 475
 476	/* lock the page head first in order to avoid an ABBA inefficiency */
 477	if (!nfs_lock_request(head)) {
 478		ret = nfs_wait_on_request(head);
 479		nfs_release_request(head);
 480		if (ret < 0)
 481			return ERR_PTR(ret);
 482		goto try_again;
 483	}
 484
 485	/* Ensure that nobody removed the request before we locked it */
 486	if (head != nfs_page_private_request(page) && !PageSwapCache(page)) {
 487		nfs_unlock_and_release_request(head);
 488		goto try_again;
 489	}
 490
 491	ret = nfs_page_group_lock(head);
 492	if (ret < 0)
 493		goto release_request;
 494
 495	/* lock each request in the page group */
 496	total_bytes = head->wb_bytes;
 497	for (subreq = head->wb_this_page; subreq != head;
 498			subreq = subreq->wb_this_page) {
 499
 500		if (!kref_get_unless_zero(&subreq->wb_kref)) {
 501			if (subreq->wb_offset == head->wb_offset + total_bytes)
 502				total_bytes += subreq->wb_bytes;
 503			continue;
 504		}
 505
 506		while (!nfs_lock_request(subreq)) {
 507			/*
 508			 * Unlock page to allow nfs_page_group_sync_on_bit()
 509			 * to succeed
 510			 */
 511			nfs_page_group_unlock(head);
 512			ret = nfs_wait_on_request(subreq);
 513			if (!ret)
 514				ret = nfs_page_group_lock(head);
 515			if (ret < 0) {
 516				nfs_unroll_locks(inode, head, subreq);
 517				nfs_release_request(subreq);
 518				goto release_request;
 519			}
 520		}
 521		/*
 522		 * Subrequests are always contiguous, non overlapping
 523		 * and in order - but may be repeated (mirrored writes).
 524		 */
 525		if (subreq->wb_offset == (head->wb_offset + total_bytes)) {
 526			/* keep track of how many bytes this group covers */
 527			total_bytes += subreq->wb_bytes;
 528		} else if (WARN_ON_ONCE(subreq->wb_offset < head->wb_offset ||
 529			    ((subreq->wb_offset + subreq->wb_bytes) >
 530			     (head->wb_offset + total_bytes)))) {
 531			nfs_page_group_unlock(head);
 532			nfs_unroll_locks(inode, head, subreq);
 533			nfs_unlock_and_release_request(subreq);
 534			ret = -EIO;
 535			goto release_request;
 536		}
 537	}
 538
 
 
 
 
 
 539	/* Now that all requests are locked, make sure they aren't on any list.
 540	 * Commit list removal accounting is done after locks are dropped */
 541	subreq = head;
 542	do {
 543		nfs_clear_request_commit(subreq);
 544		subreq = subreq->wb_this_page;
 545	} while (subreq != head);
 546
 547	/* unlink subrequests from head, destroy them later */
 548	if (head->wb_this_page != head) {
 549		/* destroy list will be terminated by head */
 550		destroy_list = head->wb_this_page;
 551		head->wb_this_page = head;
 552
 553		/* change head request to cover whole range that
 554		 * the former page group covered */
 555		head->wb_bytes = total_bytes;
 556	}
 557
 558	/* Postpone destruction of this request */
 559	if (test_and_clear_bit(PG_REMOVE, &head->wb_flags)) {
 560		set_bit(PG_INODE_REF, &head->wb_flags);
 561		kref_get(&head->wb_kref);
 562		atomic_long_inc(&NFS_I(inode)->nrequests);
 563	}
 564
 565	nfs_page_group_unlock(head);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 566
 567	nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
 
 
 
 
 
 
 
 568
 569	/* Did we lose a race with nfs_inode_remove_request()? */
 570	if (!(PagePrivate(page) || PageSwapCache(page))) {
 
 571		nfs_unlock_and_release_request(head);
 572		return NULL;
 573	}
 574
 575	/* still holds ref on head from nfs_page_find_head_request
 576	 * and still has lock on head from lock loop */
 577	return head;
 578
 579release_request:
 580	nfs_unlock_and_release_request(head);
 581	return ERR_PTR(ret);
 582}
 583
 584static void nfs_write_error_remove_page(struct nfs_page *req)
 585{
 
 
 
 586	nfs_end_page_writeback(req);
 587	generic_error_remove_page(page_file_mapping(req->wb_page),
 588				  req->wb_page);
 589	nfs_release_request(req);
 590}
 591
 592static bool
 593nfs_error_is_fatal_on_server(int err)
 594{
 595	switch (err) {
 596	case 0:
 597	case -ERESTARTSYS:
 598	case -EINTR:
 599		return false;
 600	}
 601	return nfs_error_is_fatal(err);
 602}
 603
 604/*
 605 * Find an associated nfs write request, and prepare to flush it out
 606 * May return an error if the user signalled nfs_wait_on_request().
 607 */
 608static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 609				struct page *page)
 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	ret = 0;
 625	/* If there is a fatal error that covers this write, just exit */
 626	if (nfs_error_is_fatal_on_server(req->wb_context->error))
 
 627		goto out_launder;
 628
 
 629	if (!nfs_pageio_add_request(pgio, req)) {
 630		ret = pgio->pg_error;
 631		/*
 632		 * Remove the problematic req upon fatal errors on the server
 633		 */
 634		if (nfs_error_is_fatal(ret)) {
 635			nfs_context_set_write_error(req->wb_context, ret);
 636			if (nfs_error_is_fatal_on_server(ret))
 637				goto out_launder;
 638		}
 
 639		nfs_redirty_request(req);
 640		ret = -EAGAIN;
 641	} else
 642		nfs_add_stats(page_file_mapping(page)->host,
 643				NFSIOS_WRITEPAGES, 1);
 644out:
 645	return ret;
 646out_launder:
 647	nfs_write_error_remove_page(req);
 648	return ret;
 649}
 650
 651static int nfs_do_writepage(struct page *page, struct writeback_control *wbc,
 652			    struct nfs_pageio_descriptor *pgio)
 653{
 654	int ret;
 655
 656	nfs_pageio_cond_complete(pgio, page_index(page));
 657	ret = nfs_page_async_flush(pgio, page);
 658	if (ret == -EAGAIN) {
 659		redirty_page_for_writepage(wbc, page);
 660		ret = 0;
 661	}
 662	return ret;
 663}
 664
 665/*
 666 * Write an mmapped page to the server.
 667 */
 668static int nfs_writepage_locked(struct page *page,
 669				struct writeback_control *wbc)
 670{
 671	struct nfs_pageio_descriptor pgio;
 672	struct inode *inode = page_file_mapping(page)->host;
 673	int err;
 674
 675	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 676	nfs_pageio_init_write(&pgio, inode, 0,
 677				false, &nfs_async_write_completion_ops);
 678	err = nfs_do_writepage(page, wbc, &pgio);
 
 679	nfs_pageio_complete(&pgio);
 680	if (err < 0)
 681		return err;
 682	if (pgio.pg_error < 0)
 683		return pgio.pg_error;
 684	return 0;
 685}
 686
 687int nfs_writepage(struct page *page, struct writeback_control *wbc)
 688{
 689	int ret;
 690
 691	ret = nfs_writepage_locked(page, wbc);
 692	unlock_page(page);
 
 693	return ret;
 694}
 695
 696static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
 697{
 698	int ret;
 699
 700	ret = nfs_do_writepage(page, wbc, data);
 701	unlock_page(page);
 
 702	return ret;
 703}
 704
 705static void nfs_io_completion_commit(void *inode)
 706{
 707	nfs_commit_inode(inode, 0);
 708}
 709
 710int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 711{
 712	struct inode *inode = mapping->host;
 713	struct nfs_pageio_descriptor pgio;
 714	struct nfs_io_completion *ioc = nfs_io_completion_alloc(GFP_NOFS);
 
 
 715	int err;
 716
 717	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 718
 719	if (ioc)
 720		nfs_io_completion_init(ioc, nfs_io_completion_commit, inode);
 
 
 
 
 
 
 721
 722	nfs_pageio_init_write(&pgio, inode, wb_priority(wbc), false,
 723				&nfs_async_write_completion_ops);
 724	pgio.pg_io_completion = ioc;
 725	err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
 
 726	nfs_pageio_complete(&pgio);
 727	nfs_io_completion_put(ioc);
 728
 729	if (err < 0)
 730		goto out_err;
 731	err = pgio.pg_error;
 732	if (err < 0)
 733		goto out_err;
 734	return 0;
 735out_err:
 736	return err;
 737}
 738
 739/*
 740 * Insert a write request into an inode
 741 */
 742static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 743{
 744	struct address_space *mapping = page_file_mapping(req->wb_page);
 745	struct nfs_inode *nfsi = NFS_I(inode);
 746
 747	WARN_ON_ONCE(req->wb_this_page != req);
 748
 749	/* Lock the request! */
 750	nfs_lock_request(req);
 751
 752	/*
 753	 * Swap-space should not get truncated. Hence no need to plug the race
 754	 * with invalidate/truncate.
 755	 */
 756	spin_lock(&mapping->private_lock);
 757	if (!nfs_have_writebacks(inode) &&
 758	    NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
 759		inode_inc_iversion_raw(inode);
 760	if (likely(!PageSwapCache(req->wb_page))) {
 761		set_bit(PG_MAPPED, &req->wb_flags);
 762		SetPagePrivate(req->wb_page);
 763		set_page_private(req->wb_page, (unsigned long)req);
 764	}
 765	spin_unlock(&mapping->private_lock);
 766	atomic_long_inc(&nfsi->nrequests);
 767	/* this a head request for a page group - mark it as having an
 768	 * extra reference so sub groups can follow suit.
 769	 * This flag also informs pgio layer when to bump nrequests when
 770	 * adding subrequests. */
 771	WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
 772	kref_get(&req->wb_kref);
 773}
 774
 775/*
 776 * Remove a write request from an inode
 777 */
 778static void nfs_inode_remove_request(struct nfs_page *req)
 779{
 780	struct address_space *mapping = page_file_mapping(req->wb_page);
 781	struct inode *inode = mapping->host;
 782	struct nfs_inode *nfsi = NFS_I(inode);
 783	struct nfs_page *head;
 784
 785	atomic_long_dec(&nfsi->nrequests);
 786	if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
 787		head = req->wb_head;
 788
 789		spin_lock(&mapping->private_lock);
 790		if (likely(head->wb_page && !PageSwapCache(head->wb_page))) {
 791			set_page_private(head->wb_page, 0);
 792			ClearPagePrivate(head->wb_page);
 793			clear_bit(PG_MAPPED, &head->wb_flags);
 794		}
 795		spin_unlock(&mapping->private_lock);
 796	}
 797
 798	if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags))
 799		nfs_release_request(req);
 
 
 800}
 801
 802static void
 803nfs_mark_request_dirty(struct nfs_page *req)
 804{
 805	if (req->wb_page)
 806		__set_page_dirty_nobuffers(req->wb_page);
 807}
 808
 809/*
 810 * nfs_page_search_commits_for_head_request_locked
 811 *
 812 * Search through commit lists on @inode for the head request for @page.
 813 * Must be called while holding the inode (which is cinfo) lock.
 814 *
 815 * Returns the head request if found, or NULL if not found.
 816 */
 817static struct nfs_page *
 818nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
 819						struct page *page)
 820{
 821	struct nfs_page *freq, *t;
 822	struct nfs_commit_info cinfo;
 823	struct inode *inode = &nfsi->vfs_inode;
 824
 825	nfs_init_cinfo_from_inode(&cinfo, inode);
 826
 827	/* search through pnfs commit lists */
 828	freq = pnfs_search_commit_reqs(inode, &cinfo, page);
 829	if (freq)
 830		return freq->wb_head;
 831
 832	/* Linearly search the commit list for the correct request */
 833	list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) {
 834		if (freq->wb_page == page)
 835			return freq->wb_head;
 836	}
 837
 838	return NULL;
 839}
 840
 841/**
 842 * nfs_request_add_commit_list_locked - add request to a commit list
 843 * @req: pointer to a struct nfs_page
 844 * @dst: commit list head
 845 * @cinfo: holds list lock and accounting info
 846 *
 847 * This sets the PG_CLEAN bit, updates the cinfo count of
 848 * number of outstanding requests requiring a commit as well as
 849 * the MM page stats.
 850 *
 851 * The caller must hold NFS_I(cinfo->inode)->commit_mutex, and the
 852 * nfs_page lock.
 853 */
 854void
 855nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
 856			    struct nfs_commit_info *cinfo)
 857{
 858	set_bit(PG_CLEAN, &req->wb_flags);
 859	nfs_list_add_request(req, dst);
 860	atomic_long_inc(&cinfo->mds->ncommit);
 861}
 862EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
 863
 864/**
 865 * nfs_request_add_commit_list - add request to a commit list
 866 * @req: pointer to a struct nfs_page
 867 * @dst: commit list head
 868 * @cinfo: holds list lock and accounting info
 869 *
 870 * This sets the PG_CLEAN bit, updates the cinfo count of
 871 * number of outstanding requests requiring a commit as well as
 872 * the MM page stats.
 873 *
 874 * The caller must _not_ hold the cinfo->lock, but must be
 875 * holding the nfs_page lock.
 876 */
 877void
 878nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
 879{
 880	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
 881	nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
 882	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
 883	if (req->wb_page)
 884		nfs_mark_page_unstable(req->wb_page, cinfo);
 885}
 886EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
 887
 888/**
 889 * nfs_request_remove_commit_list - Remove request from a commit list
 890 * @req: pointer to a nfs_page
 891 * @cinfo: holds list lock and accounting info
 892 *
 893 * This clears the PG_CLEAN bit, and updates the cinfo's count of
 894 * number of outstanding requests requiring a commit
 895 * It does not update the MM page stats.
 896 *
 897 * The caller _must_ hold the cinfo->lock and the nfs_page lock.
 898 */
 899void
 900nfs_request_remove_commit_list(struct nfs_page *req,
 901			       struct nfs_commit_info *cinfo)
 902{
 903	if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
 904		return;
 905	nfs_list_remove_request(req);
 906	atomic_long_dec(&cinfo->mds->ncommit);
 907}
 908EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
 909
 910static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
 911				      struct inode *inode)
 912{
 913	cinfo->inode = inode;
 914	cinfo->mds = &NFS_I(inode)->commit_info;
 915	cinfo->ds = pnfs_get_ds_info(inode);
 916	cinfo->dreq = NULL;
 917	cinfo->completion_ops = &nfs_commit_completion_ops;
 918}
 919
 920void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 921		    struct inode *inode,
 922		    struct nfs_direct_req *dreq)
 923{
 924	if (dreq)
 925		nfs_init_cinfo_from_dreq(cinfo, dreq);
 926	else
 927		nfs_init_cinfo_from_inode(cinfo, inode);
 928}
 929EXPORT_SYMBOL_GPL(nfs_init_cinfo);
 930
 931/*
 932 * Add a request to the inode's commit list.
 933 */
 934void
 935nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
 936			struct nfs_commit_info *cinfo, u32 ds_commit_idx)
 937{
 938	if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx))
 939		return;
 940	nfs_request_add_commit_list(req, cinfo);
 941}
 942
 943static void
 944nfs_clear_page_commit(struct page *page)
 945{
 946	dec_node_page_state(page, NR_UNSTABLE_NFS);
 947	dec_wb_stat(&inode_to_bdi(page_file_mapping(page)->host)->wb,
 948		    WB_RECLAIMABLE);
 949}
 950
 951/* Called holding the request lock on @req */
 952static void
 953nfs_clear_request_commit(struct nfs_page *req)
 954{
 955	if (test_bit(PG_CLEAN, &req->wb_flags)) {
 956		struct inode *inode = d_inode(req->wb_context->dentry);
 
 957		struct nfs_commit_info cinfo;
 958
 959		nfs_init_cinfo_from_inode(&cinfo, inode);
 960		mutex_lock(&NFS_I(inode)->commit_mutex);
 961		if (!pnfs_clear_request_commit(req, &cinfo)) {
 962			nfs_request_remove_commit_list(req, &cinfo);
 963		}
 964		mutex_unlock(&NFS_I(inode)->commit_mutex);
 965		nfs_clear_page_commit(req->wb_page);
 966	}
 967}
 968
 969int nfs_write_need_commit(struct nfs_pgio_header *hdr)
 970{
 971	if (hdr->verf.committed == NFS_DATA_SYNC)
 972		return hdr->lseg == NULL;
 973	return hdr->verf.committed != NFS_FILE_SYNC;
 974}
 975
 976static void nfs_async_write_init(struct nfs_pgio_header *hdr)
 977{
 978	nfs_io_completion_get(hdr->io_completion);
 979}
 980
 981static void nfs_write_completion(struct nfs_pgio_header *hdr)
 982{
 983	struct nfs_commit_info cinfo;
 984	unsigned long bytes = 0;
 985
 986	if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
 987		goto out;
 988	nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
 989	while (!list_empty(&hdr->pages)) {
 990		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
 991
 992		bytes += req->wb_bytes;
 993		nfs_list_remove_request(req);
 994		if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
 995		    (hdr->good_bytes < bytes)) {
 996			nfs_set_pageerror(req->wb_page);
 997			nfs_context_set_write_error(req->wb_context, hdr->error);
 998			goto remove_req;
 999		}
1000		if (nfs_write_need_commit(hdr)) {
 
 
1001			memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
1002			nfs_mark_request_commit(req, hdr->lseg, &cinfo,
1003				hdr->pgio_mirror_idx);
1004			goto next;
1005		}
1006remove_req:
1007		nfs_inode_remove_request(req);
1008next:
1009		nfs_end_page_writeback(req);
1010		nfs_release_request(req);
1011	}
1012out:
1013	nfs_io_completion_put(hdr->io_completion);
1014	hdr->release(hdr);
1015}
1016
1017unsigned long
1018nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
1019{
1020	return atomic_long_read(&cinfo->mds->ncommit);
1021}
1022
1023/* NFS_I(cinfo->inode)->commit_mutex held by caller */
1024int
1025nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
1026		     struct nfs_commit_info *cinfo, int max)
1027{
1028	struct nfs_page *req, *tmp;
1029	int ret = 0;
1030
1031restart:
1032	list_for_each_entry_safe(req, tmp, src, wb_list) {
1033		kref_get(&req->wb_kref);
1034		if (!nfs_lock_request(req)) {
1035			int status;
1036
1037			/* Prevent deadlock with nfs_lock_and_join_requests */
1038			if (!list_empty(dst)) {
1039				nfs_release_request(req);
1040				continue;
1041			}
1042			/* Ensure we make progress to prevent livelock */
1043			mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
1044			status = nfs_wait_on_request(req);
1045			nfs_release_request(req);
1046			mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
1047			if (status < 0)
1048				break;
1049			goto restart;
1050		}
1051		nfs_request_remove_commit_list(req, cinfo);
1052		clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
1053		nfs_list_add_request(req, dst);
1054		ret++;
1055		if ((ret == max) && !cinfo->dreq)
1056			break;
1057		cond_resched();
1058	}
1059	return ret;
1060}
1061EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
1062
1063/*
1064 * nfs_scan_commit - Scan an inode for commit requests
1065 * @inode: NFS inode to scan
1066 * @dst: mds destination list
1067 * @cinfo: mds and ds lists of reqs ready to commit
1068 *
1069 * Moves requests from the inode's 'commit' request list.
1070 * The requests are *not* checked to ensure that they form a contiguous set.
1071 */
1072int
1073nfs_scan_commit(struct inode *inode, struct list_head *dst,
1074		struct nfs_commit_info *cinfo)
1075{
1076	int ret = 0;
1077
1078	if (!atomic_long_read(&cinfo->mds->ncommit))
1079		return 0;
1080	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
1081	if (atomic_long_read(&cinfo->mds->ncommit) > 0) {
1082		const int max = INT_MAX;
1083
1084		ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
1085					   cinfo, max);
1086		ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
1087	}
1088	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
1089	return ret;
1090}
1091
1092/*
1093 * Search for an existing write request, and attempt to update
1094 * it to reflect a new dirty region on a given page.
1095 *
1096 * If the attempt fails, then the existing request is flushed out
1097 * to disk.
1098 */
1099static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
1100		struct page *page,
1101		unsigned int offset,
1102		unsigned int bytes)
1103{
1104	struct nfs_page *req;
1105	unsigned int rqend;
1106	unsigned int end;
1107	int error;
1108
1109	end = offset + bytes;
1110
1111	req = nfs_lock_and_join_requests(page);
1112	if (IS_ERR_OR_NULL(req))
1113		return req;
1114
1115	rqend = req->wb_offset + req->wb_bytes;
1116	/*
1117	 * Tell the caller to flush out the request if
1118	 * the offsets are non-contiguous.
1119	 * Note: nfs_flush_incompatible() will already
1120	 * have flushed out requests having wrong owners.
1121	 */
1122	if (offset > rqend || end < req->wb_offset)
1123		goto out_flushme;
1124
1125	/* Okay, the request matches. Update the region */
1126	if (offset < req->wb_offset) {
1127		req->wb_offset = offset;
1128		req->wb_pgbase = offset;
1129	}
1130	if (end > rqend)
1131		req->wb_bytes = end - req->wb_offset;
1132	else
1133		req->wb_bytes = rqend - req->wb_offset;
 
1134	return req;
1135out_flushme:
1136	/*
1137	 * Note: we mark the request dirty here because
1138	 * nfs_lock_and_join_requests() cannot preserve
1139	 * commit flags, so we have to replay the write.
1140	 */
1141	nfs_mark_request_dirty(req);
1142	nfs_unlock_and_release_request(req);
1143	error = nfs_wb_page(inode, page);
1144	return (error < 0) ? ERR_PTR(error) : NULL;
1145}
1146
1147/*
1148 * Try to update an existing write request, or create one if there is none.
1149 *
1150 * Note: Should always be called with the Page Lock held to prevent races
1151 * if we have to add a new request. Also assumes that the caller has
1152 * already called nfs_flush_incompatible() if necessary.
1153 */
1154static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
1155		struct page *page, unsigned int offset, unsigned int bytes)
1156{
1157	struct inode *inode = page_file_mapping(page)->host;
1158	struct nfs_page	*req;
1159
1160	req = nfs_try_to_update_request(inode, page, offset, bytes);
1161	if (req != NULL)
1162		goto out;
1163	req = nfs_create_request(ctx, page, NULL, offset, bytes);
1164	if (IS_ERR(req))
1165		goto out;
1166	nfs_inode_add_request(inode, req);
1167out:
1168	return req;
1169}
1170
1171static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
1172		unsigned int offset, unsigned int count)
1173{
1174	struct nfs_page	*req;
1175
1176	req = nfs_setup_write_request(ctx, page, offset, count);
1177	if (IS_ERR(req))
1178		return PTR_ERR(req);
1179	/* Update file length */
1180	nfs_grow_file(page, offset, count);
1181	nfs_mark_uptodate(req);
1182	nfs_mark_request_dirty(req);
1183	nfs_unlock_and_release_request(req);
1184	return 0;
1185}
1186
1187int nfs_flush_incompatible(struct file *file, struct page *page)
1188{
1189	struct nfs_open_context *ctx = nfs_file_open_context(file);
1190	struct nfs_lock_context *l_ctx;
1191	struct file_lock_context *flctx = file_inode(file)->i_flctx;
1192	struct nfs_page	*req;
1193	int do_flush, status;
1194	/*
1195	 * Look for a request corresponding to this page. If there
1196	 * is one, and it belongs to another file, we flush it out
1197	 * before we try to copy anything into the page. Do this
1198	 * due to the lack of an ACCESS-type call in NFSv2.
1199	 * Also do the same if we find a request from an existing
1200	 * dropped page.
1201	 */
1202	do {
1203		req = nfs_page_find_head_request(page);
1204		if (req == NULL)
1205			return 0;
1206		l_ctx = req->wb_lock_context;
1207		do_flush = req->wb_page != page ||
1208			!nfs_match_open_context(req->wb_context, ctx);
1209		if (l_ctx && flctx &&
1210		    !(list_empty_careful(&flctx->flc_posix) &&
1211		      list_empty_careful(&flctx->flc_flock))) {
1212			do_flush |= l_ctx->lockowner != current->files;
1213		}
1214		nfs_release_request(req);
1215		if (!do_flush)
1216			return 0;
1217		status = nfs_wb_page(page_file_mapping(page)->host, page);
1218	} while (status == 0);
1219	return status;
1220}
1221
1222/*
1223 * Avoid buffered writes when a open context credential's key would
1224 * expire soon.
1225 *
1226 * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
1227 *
1228 * Return 0 and set a credential flag which triggers the inode to flush
1229 * and performs  NFS_FILE_SYNC writes if the key will expired within
1230 * RPC_KEY_EXPIRE_TIMEO.
1231 */
1232int
1233nfs_key_timeout_notify(struct file *filp, struct inode *inode)
1234{
1235	struct nfs_open_context *ctx = nfs_file_open_context(filp);
1236	struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
1237
1238	return rpcauth_key_timeout_notify(auth, ctx->cred);
 
 
 
 
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
1248	return rpcauth_cred_key_to_expire(auth, ctx->cred);
 
 
 
 
 
 
 
 
 
 
 
1249}
1250
1251/*
1252 * If the page cache is marked as unsafe or invalid, then we can't rely on
1253 * the PageUptodate() flag. In this case, we will need to turn off
1254 * write optimisations that depend on the page contents being correct.
1255 */
1256static bool nfs_write_pageuptodate(struct page *page, struct inode *inode)
 
1257{
1258	struct nfs_inode *nfsi = NFS_I(inode);
1259
1260	if (nfs_have_delegated_attributes(inode))
1261		goto out;
1262	if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
 
1263		return false;
1264	smp_rmb();
1265	if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags))
1266		return false;
1267out:
1268	if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
1269		return false;
1270	return PageUptodate(page) != 0;
1271}
1272
1273static bool
1274is_whole_file_wrlock(struct file_lock *fl)
1275{
1276	return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX &&
1277			fl->fl_type == F_WRLCK;
1278}
1279
1280/* If we know the page is up to date, and we're not using byte range locks (or
1281 * if we have the whole file locked for writing), it may be more efficient to
1282 * extend the write to cover the entire page in order to avoid fragmentation
1283 * inefficiencies.
1284 *
1285 * If the file is opened for synchronous writes then we can just skip the rest
1286 * of the checks.
1287 */
1288static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode)
 
1289{
1290	int ret;
1291	struct file_lock_context *flctx = inode->i_flctx;
1292	struct file_lock *fl;
1293
1294	if (file->f_flags & O_DSYNC)
1295		return 0;
1296	if (!nfs_write_pageuptodate(page, inode))
1297		return 0;
1298	if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
1299		return 1;
1300	if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
1301		       list_empty_careful(&flctx->flc_posix)))
1302		return 1;
1303
1304	/* Check to see if there are whole file write locks */
1305	ret = 0;
1306	spin_lock(&flctx->flc_lock);
1307	if (!list_empty(&flctx->flc_posix)) {
1308		fl = list_first_entry(&flctx->flc_posix, struct file_lock,
1309					fl_list);
1310		if (is_whole_file_wrlock(fl))
1311			ret = 1;
1312	} else if (!list_empty(&flctx->flc_flock)) {
1313		fl = list_first_entry(&flctx->flc_flock, struct file_lock,
1314					fl_list);
1315		if (fl->fl_type == F_WRLCK)
1316			ret = 1;
1317	}
1318	spin_unlock(&flctx->flc_lock);
1319	return ret;
1320}
1321
1322/*
1323 * Update and possibly write a cached page of an NFS file.
1324 *
1325 * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
1326 * things with a page scheduled for an RPC call (e.g. invalidate it).
1327 */
1328int nfs_updatepage(struct file *file, struct page *page,
1329		unsigned int offset, unsigned int count)
1330{
1331	struct nfs_open_context *ctx = nfs_file_open_context(file);
1332	struct inode	*inode = page_file_mapping(page)->host;
 
 
1333	int		status = 0;
1334
1335	nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
1336
1337	dprintk("NFS:       nfs_updatepage(%pD2 %d@%lld)\n",
1338		file, count, (long long)(page_file_offset(page) + offset));
1339
1340	if (!count)
1341		goto out;
1342
1343	if (nfs_can_extend_write(file, page, inode)) {
1344		count = max(count + offset, nfs_page_length(page));
1345		offset = 0;
1346	}
1347
1348	status = nfs_writepage_setup(ctx, page, offset, count);
1349	if (status < 0)
1350		nfs_set_pageerror(page);
1351	else
1352		__set_page_dirty_nobuffers(page);
1353out:
1354	dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
1355			status, (long long)i_size_read(inode));
1356	return status;
1357}
1358
1359static int flush_task_priority(int how)
1360{
1361	switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
1362		case FLUSH_HIGHPRI:
1363			return RPC_PRIORITY_HIGH;
1364		case FLUSH_LOWPRI:
1365			return RPC_PRIORITY_LOW;
1366	}
1367	return RPC_PRIORITY_NORMAL;
1368}
1369
1370static void nfs_initiate_write(struct nfs_pgio_header *hdr,
1371			       struct rpc_message *msg,
1372			       const struct nfs_rpc_ops *rpc_ops,
1373			       struct rpc_task_setup *task_setup_data, int how)
1374{
1375	int priority = flush_task_priority(how);
1376
1377	task_setup_data->priority = priority;
1378	rpc_ops->write_setup(hdr, msg);
1379	trace_nfs_initiate_write(hdr->inode, hdr->io_start, hdr->good_bytes,
1380				 hdr->args.stable);
1381
1382	nfs4_state_protect_write(NFS_SERVER(hdr->inode)->nfs_client,
1383				 &task_setup_data->rpc_client, msg, hdr);
1384}
1385
1386/* If a nfs_flush_* function fails, it should remove reqs from @head and
1387 * call this on each, which will prepare them to be retried on next
1388 * writeback using standard nfs.
1389 */
1390static void nfs_redirty_request(struct nfs_page *req)
1391{
 
 
1392	nfs_mark_request_dirty(req);
1393	set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags);
1394	nfs_end_page_writeback(req);
1395	nfs_release_request(req);
1396}
1397
1398static void nfs_async_write_error(struct list_head *head)
1399{
1400	struct nfs_page	*req;
1401
1402	while (!list_empty(head)) {
1403		req = nfs_list_entry(head->next);
1404		nfs_list_remove_request(req);
1405		nfs_redirty_request(req);
 
 
 
1406	}
1407}
1408
1409static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)
1410{
1411	nfs_async_write_error(&hdr->pages);
 
 
1412}
1413
1414static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
1415	.init_hdr = nfs_async_write_init,
1416	.error_cleanup = nfs_async_write_error,
1417	.completion = nfs_write_completion,
1418	.reschedule_io = nfs_async_write_reschedule_io,
1419};
1420
1421void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1422			       struct inode *inode, int ioflags, bool force_mds,
1423			       const struct nfs_pgio_completion_ops *compl_ops)
1424{
1425	struct nfs_server *server = NFS_SERVER(inode);
1426	const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
1427
1428#ifdef CONFIG_NFS_V4_1
1429	if (server->pnfs_curr_ld && !force_mds)
1430		pg_ops = server->pnfs_curr_ld->pg_write_ops;
1431#endif
1432	nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops,
1433			server->wsize, ioflags);
1434}
1435EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
1436
1437void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1438{
1439	struct nfs_pgio_mirror *mirror;
1440
1441	if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
1442		pgio->pg_ops->pg_cleanup(pgio);
1443
1444	pgio->pg_ops = &nfs_pgio_rw_ops;
1445
1446	nfs_pageio_stop_mirroring(pgio);
1447
1448	mirror = &pgio->pg_mirrors[0];
1449	mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1450}
1451EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1452
1453
1454void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1455{
1456	struct nfs_commit_data *data = calldata;
1457
1458	NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1459}
1460
1461/*
1462 * Special version of should_remove_suid() that ignores capabilities.
1463 */
1464static int nfs_should_remove_suid(const struct inode *inode)
1465{
1466	umode_t mode = inode->i_mode;
1467	int kill = 0;
1468
1469	/* suid always must be killed */
1470	if (unlikely(mode & S_ISUID))
1471		kill = ATTR_KILL_SUID;
1472
1473	/*
1474	 * sgid without any exec bits is just a mandatory locking mark; leave
1475	 * it alone.  If some exec bits are set, it's a real sgid; kill it.
1476	 */
1477	if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
1478		kill |= ATTR_KILL_SGID;
1479
1480	if (unlikely(kill && S_ISREG(mode)))
1481		return kill;
1482
1483	return 0;
1484}
1485
1486static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
1487		struct nfs_fattr *fattr)
1488{
1489	struct nfs_pgio_args *argp = &hdr->args;
1490	struct nfs_pgio_res *resp = &hdr->res;
1491	u64 size = argp->offset + resp->count;
1492
1493	if (!(fattr->valid & NFS_ATTR_FATTR_SIZE))
1494		fattr->size = size;
1495	if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) {
1496		fattr->valid &= ~NFS_ATTR_FATTR_SIZE;
1497		return;
1498	}
1499	if (size != fattr->size)
1500		return;
1501	/* Set attribute barrier */
1502	nfs_fattr_set_barrier(fattr);
1503	/* ...and update size */
1504	fattr->valid |= NFS_ATTR_FATTR_SIZE;
1505}
1506
1507void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
1508{
1509	struct nfs_fattr *fattr = &hdr->fattr;
1510	struct inode *inode = hdr->inode;
1511
1512	spin_lock(&inode->i_lock);
1513	nfs_writeback_check_extend(hdr, fattr);
1514	nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
1515	spin_unlock(&inode->i_lock);
1516}
1517EXPORT_SYMBOL_GPL(nfs_writeback_update_inode);
1518
1519/*
1520 * This function is called when the WRITE call is complete.
1521 */
1522static int nfs_writeback_done(struct rpc_task *task,
1523			      struct nfs_pgio_header *hdr,
1524			      struct inode *inode)
1525{
1526	int status;
1527
1528	/*
1529	 * ->write_done will attempt to use post-op attributes to detect
1530	 * conflicting writes by other clients.  A strict interpretation
1531	 * of close-to-open would allow us to continue caching even if
1532	 * another writer had changed the file, but some applications
1533	 * depend on tighter cache coherency when writing.
1534	 */
1535	status = NFS_PROTO(inode)->write_done(task, hdr);
1536	if (status != 0)
1537		return status;
1538
1539	nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count);
1540	trace_nfs_writeback_done(inode, task->tk_status,
1541				 hdr->args.offset, hdr->res.verf);
1542
1543	if (hdr->res.verf->committed < hdr->args.stable &&
1544	    task->tk_status >= 0) {
1545		/* We tried a write call, but the server did not
1546		 * commit data to stable storage even though we
1547		 * requested it.
1548		 * Note: There is a known bug in Tru64 < 5.0 in which
1549		 *	 the server reports NFS_DATA_SYNC, but performs
1550		 *	 NFS_FILE_SYNC. We therefore implement this checking
1551		 *	 as a dprintk() in order to avoid filling syslog.
1552		 */
1553		static unsigned long    complain;
1554
1555		/* Note this will print the MDS for a DS write */
1556		if (time_before(complain, jiffies)) {
1557			dprintk("NFS:       faulty NFS server %s:"
1558				" (committed = %d) != (stable = %d)\n",
1559				NFS_SERVER(inode)->nfs_client->cl_hostname,
1560				hdr->res.verf->committed, hdr->args.stable);
1561			complain = jiffies + 300 * HZ;
1562		}
1563	}
1564
1565	/* Deal with the suid/sgid bit corner case */
1566	if (nfs_should_remove_suid(inode)) {
1567		spin_lock(&inode->i_lock);
1568		NFS_I(inode)->cache_validity |= NFS_INO_INVALID_OTHER;
1569		spin_unlock(&inode->i_lock);
1570	}
1571	return 0;
1572}
1573
1574/*
1575 * This function is called when the WRITE call is complete.
1576 */
1577static void nfs_writeback_result(struct rpc_task *task,
1578				 struct nfs_pgio_header *hdr)
1579{
1580	struct nfs_pgio_args	*argp = &hdr->args;
1581	struct nfs_pgio_res	*resp = &hdr->res;
1582
1583	if (resp->count < argp->count) {
1584		static unsigned long    complain;
1585
1586		/* This a short write! */
1587		nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE);
1588
1589		/* Has the server at least made some progress? */
1590		if (resp->count == 0) {
1591			if (time_before(complain, jiffies)) {
1592				printk(KERN_WARNING
1593				       "NFS: Server wrote zero bytes, expected %u.\n",
1594				       argp->count);
1595				complain = jiffies + 300 * HZ;
1596			}
1597			nfs_set_pgio_error(hdr, -EIO, argp->offset);
1598			task->tk_status = -EIO;
1599			return;
1600		}
1601
1602		/* For non rpc-based layout drivers, retry-through-MDS */
1603		if (!task->tk_ops) {
1604			hdr->pnfs_error = -EAGAIN;
1605			return;
1606		}
1607
1608		/* Was this an NFSv2 write or an NFSv3 stable write? */
1609		if (resp->verf->committed != NFS_UNSTABLE) {
1610			/* Resend from where the server left off */
1611			hdr->mds_offset += resp->count;
1612			argp->offset += resp->count;
1613			argp->pgbase += resp->count;
1614			argp->count -= resp->count;
1615		} else {
1616			/* Resend as a stable write in order to avoid
1617			 * headaches in the case of a server crash.
1618			 */
1619			argp->stable = NFS_FILE_SYNC;
1620		}
 
 
1621		rpc_restart_call_prepare(task);
1622	}
1623}
1624
1625static int wait_on_commit(struct nfs_mds_commit_info *cinfo)
1626{
1627	return wait_var_event_killable(&cinfo->rpcs_out,
1628				       !atomic_read(&cinfo->rpcs_out));
1629}
1630
1631static void nfs_commit_begin(struct nfs_mds_commit_info *cinfo)
1632{
1633	atomic_inc(&cinfo->rpcs_out);
1634}
1635
1636static void nfs_commit_end(struct nfs_mds_commit_info *cinfo)
1637{
1638	if (atomic_dec_and_test(&cinfo->rpcs_out))
1639		wake_up_var(&cinfo->rpcs_out);
1640}
1641
1642void nfs_commitdata_release(struct nfs_commit_data *data)
1643{
1644	put_nfs_open_context(data->context);
1645	nfs_commit_free(data);
1646}
1647EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1648
1649int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
1650			const struct nfs_rpc_ops *nfs_ops,
1651			const struct rpc_call_ops *call_ops,
1652			int how, int flags)
1653{
1654	struct rpc_task *task;
1655	int priority = flush_task_priority(how);
1656	struct rpc_message msg = {
1657		.rpc_argp = &data->args,
1658		.rpc_resp = &data->res,
1659		.rpc_cred = data->cred,
1660	};
1661	struct rpc_task_setup task_setup_data = {
1662		.task = &data->task,
1663		.rpc_client = clnt,
1664		.rpc_message = &msg,
1665		.callback_ops = call_ops,
1666		.callback_data = data,
1667		.workqueue = nfsiod_workqueue,
1668		.flags = RPC_TASK_ASYNC | flags,
1669		.priority = priority,
1670	};
1671	/* Set up the initial task struct.  */
1672	nfs_ops->commit_setup(data, &msg);
1673	trace_nfs_initiate_commit(data);
1674
1675	dprintk("NFS: initiated commit call\n");
1676
1677	nfs4_state_protect(NFS_SERVER(data->inode)->nfs_client,
1678		NFS_SP4_MACH_CRED_COMMIT, &task_setup_data.rpc_client, &msg);
1679
1680	task = rpc_run_task(&task_setup_data);
1681	if (IS_ERR(task))
1682		return PTR_ERR(task);
1683	if (how & FLUSH_SYNC)
1684		rpc_wait_for_completion_task(task);
1685	rpc_put_task(task);
1686	return 0;
1687}
1688EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1689
1690static loff_t nfs_get_lwb(struct list_head *head)
1691{
1692	loff_t lwb = 0;
1693	struct nfs_page *req;
1694
1695	list_for_each_entry(req, head, wb_list)
1696		if (lwb < (req_offset(req) + req->wb_bytes))
1697			lwb = req_offset(req) + req->wb_bytes;
1698
1699	return lwb;
1700}
1701
1702/*
1703 * Set up the argument/result storage required for the RPC call.
1704 */
1705void nfs_init_commit(struct nfs_commit_data *data,
1706		     struct list_head *head,
1707		     struct pnfs_layout_segment *lseg,
1708		     struct nfs_commit_info *cinfo)
1709{
1710	struct nfs_page *first = nfs_list_entry(head->next);
1711	struct inode *inode = d_inode(first->wb_context->dentry);
 
1712
1713	/* Set up the RPC argument and reply structs
1714	 * NB: take care not to mess about with data->commit et al. */
1715
1716	list_splice_init(head, &data->pages);
 
 
 
 
 
1717
1718	data->inode	  = inode;
1719	data->cred	  = first->wb_context->cred;
1720	data->lseg	  = lseg; /* reference transferred */
1721	/* only set lwb for pnfs commit */
1722	if (lseg)
1723		data->lwb = nfs_get_lwb(&data->pages);
1724	data->mds_ops     = &nfs_commit_ops;
1725	data->completion_ops = cinfo->completion_ops;
1726	data->dreq	  = cinfo->dreq;
1727
1728	data->args.fh     = NFS_FH(data->inode);
1729	/* Note: we always request a commit of the entire inode */
1730	data->args.offset = 0;
1731	data->args.count  = 0;
1732	data->context     = get_nfs_open_context(first->wb_context);
1733	data->res.fattr   = &data->fattr;
1734	data->res.verf    = &data->verf;
1735	nfs_fattr_init(&data->fattr);
1736}
1737EXPORT_SYMBOL_GPL(nfs_init_commit);
1738
1739void nfs_retry_commit(struct list_head *page_list,
1740		      struct pnfs_layout_segment *lseg,
1741		      struct nfs_commit_info *cinfo,
1742		      u32 ds_commit_idx)
1743{
1744	struct nfs_page *req;
1745
1746	while (!list_empty(page_list)) {
1747		req = nfs_list_entry(page_list->next);
1748		nfs_list_remove_request(req);
1749		nfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx);
1750		if (!cinfo->dreq)
1751			nfs_clear_page_commit(req->wb_page);
1752		nfs_unlock_and_release_request(req);
1753	}
1754}
1755EXPORT_SYMBOL_GPL(nfs_retry_commit);
1756
1757static void
1758nfs_commit_resched_write(struct nfs_commit_info *cinfo,
1759		struct nfs_page *req)
1760{
1761	__set_page_dirty_nobuffers(req->wb_page);
1762}
1763
1764/*
1765 * Commit dirty pages
1766 */
1767static int
1768nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1769		struct nfs_commit_info *cinfo)
1770{
1771	struct nfs_commit_data	*data;
 
1772
1773	/* another commit raced with us */
1774	if (list_empty(head))
1775		return 0;
1776
1777	data = nfs_commitdata_alloc(true);
1778
1779	/* Set up the argument struct */
1780	nfs_init_commit(data, head, NULL, cinfo);
1781	atomic_inc(&cinfo->mds->rpcs_out);
 
 
1782	return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode),
1783				   data->mds_ops, how, 0);
 
1784}
1785
1786/*
1787 * COMMIT call returned
1788 */
1789static void nfs_commit_done(struct rpc_task *task, void *calldata)
1790{
1791	struct nfs_commit_data	*data = calldata;
1792
1793        dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1794                                task->tk_pid, task->tk_status);
1795
1796	/* Call the NFS version-specific code */
1797	NFS_PROTO(data->inode)->commit_done(task, data);
1798	trace_nfs_commit_done(data);
1799}
1800
1801static void nfs_commit_release_pages(struct nfs_commit_data *data)
1802{
 
1803	struct nfs_page	*req;
1804	int status = data->task.tk_status;
1805	struct nfs_commit_info cinfo;
1806	struct nfs_server *nfss;
1807
1808	while (!list_empty(&data->pages)) {
1809		req = nfs_list_entry(data->pages.next);
1810		nfs_list_remove_request(req);
1811		if (req->wb_page)
1812			nfs_clear_page_commit(req->wb_page);
1813
1814		dprintk("NFS:       commit (%s/%llu %d@%lld)",
1815			req->wb_context->dentry->d_sb->s_id,
1816			(unsigned long long)NFS_FILEID(d_inode(req->wb_context->dentry)),
1817			req->wb_bytes,
1818			(long long)req_offset(req));
1819		if (status < 0) {
1820			nfs_context_set_write_error(req->wb_context, status);
1821			if (req->wb_page)
 
1822				nfs_inode_remove_request(req);
 
1823			dprintk_cont(", error = %d\n", status);
1824			goto next;
1825		}
1826
1827		/* Okay, COMMIT succeeded, apparently. Check the verifier
1828		 * returned by the server against all stored verfs. */
1829		if (!nfs_write_verifier_cmp(&req->wb_verf, &data->verf.verifier)) {
1830			/* We have a match */
1831			if (req->wb_page)
1832				nfs_inode_remove_request(req);
1833			dprintk_cont(" OK\n");
1834			goto next;
1835		}
1836		/* We have a mismatch. Write the page again */
1837		dprintk_cont(" mismatch\n");
1838		nfs_mark_request_dirty(req);
1839		set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags);
1840	next:
1841		nfs_unlock_and_release_request(req);
1842		/* Latency breaker */
1843		cond_resched();
1844	}
1845	nfss = NFS_SERVER(data->inode);
1846	if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
1847		clear_bdi_congested(inode_to_bdi(data->inode), BLK_RW_ASYNC);
1848
1849	nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1850	nfs_commit_end(cinfo.mds);
1851}
1852
1853static void nfs_commit_release(void *calldata)
1854{
1855	struct nfs_commit_data *data = calldata;
1856
1857	data->completion_ops->completion(data);
1858	nfs_commitdata_release(calldata);
1859}
1860
1861static const struct rpc_call_ops nfs_commit_ops = {
1862	.rpc_call_prepare = nfs_commit_prepare,
1863	.rpc_call_done = nfs_commit_done,
1864	.rpc_release = nfs_commit_release,
1865};
1866
1867static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1868	.completion = nfs_commit_release_pages,
1869	.resched_write = nfs_commit_resched_write,
1870};
1871
1872int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1873			    int how, struct nfs_commit_info *cinfo)
1874{
1875	int status;
1876
1877	status = pnfs_commit_list(inode, head, how, cinfo);
1878	if (status == PNFS_NOT_ATTEMPTED)
1879		status = nfs_commit_list(inode, head, how, cinfo);
1880	return status;
1881}
1882
1883static int __nfs_commit_inode(struct inode *inode, int how,
1884		struct writeback_control *wbc)
1885{
1886	LIST_HEAD(head);
1887	struct nfs_commit_info cinfo;
1888	int may_wait = how & FLUSH_SYNC;
1889	int ret, nscan;
1890
1891	nfs_init_cinfo_from_inode(&cinfo, inode);
1892	nfs_commit_begin(cinfo.mds);
1893	for (;;) {
1894		ret = nscan = nfs_scan_commit(inode, &head, &cinfo);
1895		if (ret <= 0)
1896			break;
1897		ret = nfs_generic_commit_list(inode, &head, how, &cinfo);
1898		if (ret < 0)
1899			break;
1900		ret = 0;
1901		if (wbc && wbc->sync_mode == WB_SYNC_NONE) {
1902			if (nscan < wbc->nr_to_write)
1903				wbc->nr_to_write -= nscan;
1904			else
1905				wbc->nr_to_write = 0;
1906		}
1907		if (nscan < INT_MAX)
1908			break;
1909		cond_resched();
1910	}
1911	nfs_commit_end(cinfo.mds);
1912	if (ret || !may_wait)
1913		return ret;
1914	return wait_on_commit(cinfo.mds);
1915}
1916
1917int nfs_commit_inode(struct inode *inode, int how)
1918{
1919	return __nfs_commit_inode(inode, how, NULL);
1920}
1921EXPORT_SYMBOL_GPL(nfs_commit_inode);
1922
1923int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1924{
1925	struct nfs_inode *nfsi = NFS_I(inode);
1926	int flags = FLUSH_SYNC;
1927	int ret = 0;
1928
1929	if (wbc->sync_mode == WB_SYNC_NONE) {
1930		/* no commits means nothing needs to be done */
1931		if (!atomic_long_read(&nfsi->commit_info.ncommit))
1932			goto check_requests_outstanding;
1933
1934		/* Don't commit yet if this is a non-blocking flush and there
1935		 * are a lot of outstanding writes for this mapping.
1936		 */
1937		if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))
1938			goto out_mark_dirty;
1939
1940		/* don't wait for the COMMIT response */
1941		flags = 0;
1942	}
1943
1944	ret = __nfs_commit_inode(inode, flags, wbc);
1945	if (!ret) {
1946		if (flags & FLUSH_SYNC)
1947			return 0;
1948	} else if (atomic_long_read(&nfsi->commit_info.ncommit))
1949		goto out_mark_dirty;
1950
1951check_requests_outstanding:
1952	if (!atomic_read(&nfsi->commit_info.rpcs_out))
1953		return ret;
1954out_mark_dirty:
1955	__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1956	return ret;
1957}
1958EXPORT_SYMBOL_GPL(nfs_write_inode);
1959
1960/*
1961 * Wrapper for filemap_write_and_wait_range()
1962 *
1963 * Needed for pNFS in order to ensure data becomes visible to the
1964 * client.
1965 */
1966int nfs_filemap_write_and_wait_range(struct address_space *mapping,
1967		loff_t lstart, loff_t lend)
1968{
1969	int ret;
1970
1971	ret = filemap_write_and_wait_range(mapping, lstart, lend);
1972	if (ret == 0)
1973		ret = pnfs_sync_inode(mapping->host, true);
1974	return ret;
1975}
1976EXPORT_SYMBOL_GPL(nfs_filemap_write_and_wait_range);
1977
1978/*
1979 * flush the inode to disk.
1980 */
1981int nfs_wb_all(struct inode *inode)
1982{
1983	int ret;
1984
1985	trace_nfs_writeback_inode_enter(inode);
1986
1987	ret = filemap_write_and_wait(inode->i_mapping);
1988	if (ret)
1989		goto out;
1990	ret = nfs_commit_inode(inode, FLUSH_SYNC);
1991	if (ret < 0)
1992		goto out;
1993	pnfs_sync_inode(inode, true);
1994	ret = 0;
1995
1996out:
1997	trace_nfs_writeback_inode_exit(inode, ret);
1998	return ret;
1999}
2000EXPORT_SYMBOL_GPL(nfs_wb_all);
2001
2002int nfs_wb_page_cancel(struct inode *inode, struct page *page)
2003{
2004	struct nfs_page *req;
2005	int ret = 0;
2006
2007	wait_on_page_writeback(page);
2008
2009	/* blocking call to cancel all requests and join to a single (head)
2010	 * request */
2011	req = nfs_lock_and_join_requests(page);
2012
2013	if (IS_ERR(req)) {
2014		ret = PTR_ERR(req);
2015	} else if (req) {
2016		/* all requests from this page have been cancelled by
2017		 * nfs_lock_and_join_requests, so just remove the head
2018		 * request from the inode / page_private pointer and
2019		 * release it */
2020		nfs_inode_remove_request(req);
2021		nfs_unlock_and_release_request(req);
2022	}
2023
2024	return ret;
2025}
2026
2027/*
2028 * Write back all requests on one page - we do this before reading it.
2029 */
2030int nfs_wb_page(struct inode *inode, struct page *page)
2031{
2032	loff_t range_start = page_file_offset(page);
2033	loff_t range_end = range_start + (loff_t)(PAGE_SIZE - 1);
2034	struct writeback_control wbc = {
2035		.sync_mode = WB_SYNC_ALL,
2036		.nr_to_write = 0,
2037		.range_start = range_start,
2038		.range_end = range_end,
2039	};
2040	int ret;
2041
2042	trace_nfs_writeback_page_enter(inode);
2043
2044	for (;;) {
2045		wait_on_page_writeback(page);
2046		if (clear_page_dirty_for_io(page)) {
2047			ret = nfs_writepage_locked(page, &wbc);
2048			if (ret < 0)
2049				goto out_error;
2050			continue;
2051		}
2052		ret = 0;
2053		if (!PagePrivate(page))
2054			break;
2055		ret = nfs_commit_inode(inode, FLUSH_SYNC);
2056		if (ret < 0)
2057			goto out_error;
2058	}
2059out_error:
2060	trace_nfs_writeback_page_exit(inode, ret);
2061	return ret;
2062}
2063
2064#ifdef CONFIG_MIGRATION
2065int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
2066		struct page *page, enum migrate_mode mode)
2067{
2068	/*
2069	 * If PagePrivate is set, then the page is currently associated with
2070	 * an in-progress read or write request. Don't try to migrate it.
2071	 *
2072	 * FIXME: we could do this in principle, but we'll need a way to ensure
2073	 *        that we can safely release the inode reference while holding
2074	 *        the page lock.
2075	 */
2076	if (PagePrivate(page))
2077		return -EBUSY;
2078
2079	if (!nfs_fscache_release_page(page, GFP_KERNEL))
2080		return -EBUSY;
2081
2082	return migrate_page(mapping, newpage, page, mode);
2083}
2084#endif
2085
2086int __init nfs_init_writepagecache(void)
2087{
2088	nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
2089					     sizeof(struct nfs_pgio_header),
2090					     0, SLAB_HWCACHE_ALIGN,
2091					     NULL);
2092	if (nfs_wdata_cachep == NULL)
2093		return -ENOMEM;
2094
2095	nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
2096						     nfs_wdata_cachep);
2097	if (nfs_wdata_mempool == NULL)
2098		goto out_destroy_write_cache;
2099
2100	nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
2101					     sizeof(struct nfs_commit_data),
2102					     0, SLAB_HWCACHE_ALIGN,
2103					     NULL);
2104	if (nfs_cdata_cachep == NULL)
2105		goto out_destroy_write_mempool;
2106
2107	nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
2108						      nfs_cdata_cachep);
2109	if (nfs_commit_mempool == NULL)
2110		goto out_destroy_commit_cache;
2111
2112	/*
2113	 * NFS congestion size, scale with available memory.
2114	 *
2115	 *  64MB:    8192k
2116	 * 128MB:   11585k
2117	 * 256MB:   16384k
2118	 * 512MB:   23170k
2119	 *   1GB:   32768k
2120	 *   2GB:   46340k
2121	 *   4GB:   65536k
2122	 *   8GB:   92681k
2123	 *  16GB:  131072k
2124	 *
2125	 * This allows larger machines to have larger/more transfers.
2126	 * Limit the default to 256M
2127	 */
2128	nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
2129	if (nfs_congestion_kb > 256*1024)
2130		nfs_congestion_kb = 256*1024;
2131
2132	return 0;
2133
2134out_destroy_commit_cache:
2135	kmem_cache_destroy(nfs_cdata_cachep);
2136out_destroy_write_mempool:
2137	mempool_destroy(nfs_wdata_mempool);
2138out_destroy_write_cache:
2139	kmem_cache_destroy(nfs_wdata_cachep);
2140	return -ENOMEM;
2141}
2142
2143void nfs_destroy_writepagecache(void)
2144{
2145	mempool_destroy(nfs_commit_mempool);
2146	kmem_cache_destroy(nfs_cdata_cachep);
2147	mempool_destroy(nfs_wdata_mempool);
2148	kmem_cache_destroy(nfs_wdata_cachep);
2149}
2150
2151static const struct nfs_rw_ops nfs_rw_write_ops = {
2152	.rw_alloc_header	= nfs_writehdr_alloc,
2153	.rw_free_header		= nfs_writehdr_free,
2154	.rw_done		= nfs_writeback_done,
2155	.rw_result		= nfs_writeback_result,
2156	.rw_initiate		= nfs_initiate_write,
2157};