write.c 41.6 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59
/*
 * linux/fs/nfs/write.c
 *
 * Writing file data over NFS.
 *
 * We do it like this: When a (user) process wishes to write data to an
 * NFS file, a write request is allocated that contains the RPC task data
 * plus some info on the page to be written, and added to the inode's
 * write chain. If the process writes past the end of the page, an async
 * RPC call to write the page is scheduled immediately; otherwise, the call
 * is delayed for a few seconds.
 *
 * Just like readahead, no async I/O is performed if wsize < PAGE_SIZE.
 *
 * Write requests are kept on the inode's writeback list. Each entry in
 * that list references the page (portion) to be written. When the
 * cache timeout has expired, the RPC task is woken up, and tries to
 * lock the page. As soon as it manages to do so, the request is moved
 * from the writeback list to the writelock list.
 *
 * Note: we must make sure never to confuse the inode passed in the
 * write_page request with the one in page->inode. As far as I understand
 * it, these are different when doing a swap-out.
 *
 * To understand everything that goes on here and in the NFS read code,
 * one should be aware that a page is locked in exactly one of the following
 * cases:
 *
 *  -	A write request is in progress.
 *  -	A user process is in generic_file_write/nfs_update_page
 *  -	A user process is in generic_file_read
 *
 * Also note that because of the way pages are invalidated in
 * nfs_revalidate_inode, the following assertions hold:
 *
 *  -	If a page is dirty, there will be no read requests (a page will
 *	not be re-read unless invalidated by nfs_revalidate_inode).
 *  -	If the page is not uptodate, there will be no pending write
 *	requests, and no process will be in nfs_update_page.
 *
 * FIXME: Interaction with the vmscan routines is not optimal yet.
 * Either vmscan must be made nfs-savvy, or we need a different page
 * reclaim concept that supports something like FS-independent
 * buffer_heads with a b_ops-> field.
 *
 * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/writeback.h>

#include <linux/sunrpc/clnt.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs_page.h>
60 61
#include <linux/backing-dev.h>

L
Linus Torvalds 已提交
62 63 64 65
#include <asm/uaccess.h>
#include <linux/smp_lock.h>

#include "delegation.h"
C
Chuck Lever 已提交
66
#include "iostat.h"
L
Linus Torvalds 已提交
67 68 69 70 71 72 73 74 75 76 77 78 79 80 81

#define NFSDBG_FACILITY		NFSDBG_PAGECACHE

#define MIN_POOL_WRITE		(32)
#define MIN_POOL_COMMIT		(4)

/*
 * Local function declarations
 */
static struct nfs_page * nfs_update_request(struct nfs_open_context*,
					    struct inode *,
					    struct page *,
					    unsigned int, unsigned int);
static int nfs_wait_on_write_congestion(struct address_space *, int);
static int nfs_wait_on_requests(struct inode *, unsigned long, unsigned int);
T
Trond Myklebust 已提交
82
static int nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how);
83 84 85
static const struct rpc_call_ops nfs_write_partial_ops;
static const struct rpc_call_ops nfs_write_full_ops;
static const struct rpc_call_ops nfs_commit_ops;
L
Linus Torvalds 已提交
86 87

static kmem_cache_t *nfs_wdata_cachep;
88
static mempool_t *nfs_wdata_mempool;
L
Linus Torvalds 已提交
89 90 91 92
static mempool_t *nfs_commit_mempool;

static DECLARE_WAIT_QUEUE_HEAD(nfs_write_congestion);

93
struct nfs_write_data *nfs_commit_alloc(void)
L
Linus Torvalds 已提交
94 95
{
	struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, SLAB_NOFS);
96

L
Linus Torvalds 已提交
97 98 99 100 101 102 103
	if (p) {
		memset(p, 0, sizeof(*p));
		INIT_LIST_HEAD(&p->pages);
	}
	return p;
}

104
void nfs_commit_rcu_free(struct rcu_head *head)
L
Linus Torvalds 已提交
105
{
106
	struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu);
107 108
	if (p && (p->pagevec != &p->page_array[0]))
		kfree(p->pagevec);
L
Linus Torvalds 已提交
109 110 111
	mempool_free(p, nfs_commit_mempool);
}

112 113 114 115 116
void nfs_commit_free(struct nfs_write_data *wdata)
{
	call_rcu_bh(&wdata->task.u.tk_rcu, nfs_commit_rcu_free);
}

117
struct nfs_write_data *nfs_writedata_alloc(size_t len)
118
{
119
	unsigned int pagecount = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
120 121 122 123 124
	struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, SLAB_NOFS);

	if (p) {
		memset(p, 0, sizeof(*p));
		INIT_LIST_HEAD(&p->pages);
125
		p->npages = pagecount;
126 127
		if (pagecount <= ARRAY_SIZE(p->page_array))
			p->pagevec = p->page_array;
128
		else {
129 130
			p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
			if (!p->pagevec) {
131 132 133 134 135 136 137 138
				mempool_free(p, nfs_wdata_mempool);
				p = NULL;
			}
		}
	}
	return p;
}

139
static void nfs_writedata_rcu_free(struct rcu_head *head)
140
{
141
	struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu);
142 143 144 145 146
	if (p && (p->pagevec != &p->page_array[0]))
		kfree(p->pagevec);
	mempool_free(p, nfs_wdata_mempool);
}

147 148 149 150 151
static void nfs_writedata_free(struct nfs_write_data *wdata)
{
	call_rcu_bh(&wdata->task.u.tk_rcu, nfs_writedata_rcu_free);
}

152
void nfs_writedata_release(void *wdata)
L
Linus Torvalds 已提交
153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168
{
	nfs_writedata_free(wdata);
}

/* Adjust the file length if we're writing beyond the end */
static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
{
	struct inode *inode = page->mapping->host;
	loff_t end, i_size = i_size_read(inode);
	unsigned long end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;

	if (i_size > 0 && page->index < end_index)
		return;
	end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
	if (i_size >= end)
		return;
C
Chuck Lever 已提交
169
	nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
L
Linus Torvalds 已提交
170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215
	i_size_write(inode, end);
}

/* We can set the PG_uptodate flag if we see that a write request
 * covers the full page.
 */
static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
{
	loff_t end_offs;

	if (PageUptodate(page))
		return;
	if (base != 0)
		return;
	if (count == PAGE_CACHE_SIZE) {
		SetPageUptodate(page);
		return;
	}

	end_offs = i_size_read(page->mapping->host) - 1;
	if (end_offs < 0)
		return;
	/* Is this the last page? */
	if (page->index != (unsigned long)(end_offs >> PAGE_CACHE_SHIFT))
		return;
	/* This is the last page: set PG_uptodate if we cover the entire
	 * extent of the data, then zero the rest of the page.
	 */
	if (count == (unsigned int)(end_offs & (PAGE_CACHE_SIZE - 1)) + 1) {
		memclear_highpage_flush(page, count, PAGE_CACHE_SIZE - count);
		SetPageUptodate(page);
	}
}

/*
 * Write a page synchronously.
 * Offset is the data offset within the page.
 */
static int nfs_writepage_sync(struct nfs_open_context *ctx, struct inode *inode,
		struct page *page, unsigned int offset, unsigned int count,
		int how)
{
	unsigned int	wsize = NFS_SERVER(inode)->wsize;
	int		result, written = 0;
	struct nfs_write_data *wdata;

216
	wdata = nfs_writedata_alloc(wsize);
L
Linus Torvalds 已提交
217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236
	if (!wdata)
		return -ENOMEM;

	wdata->flags = how;
	wdata->cred = ctx->cred;
	wdata->inode = inode;
	wdata->args.fh = NFS_FH(inode);
	wdata->args.context = ctx;
	wdata->args.pages = &page;
	wdata->args.stable = NFS_FILE_SYNC;
	wdata->args.pgbase = offset;
	wdata->args.count = wsize;
	wdata->res.fattr = &wdata->fattr;
	wdata->res.verf = &wdata->verf;

	dprintk("NFS:      nfs_writepage_sync(%s/%Ld %d@%Ld)\n",
		inode->i_sb->s_id,
		(long long)NFS_FILEID(inode),
		count, (long long)(page_offset(page) + offset));

237
	set_page_writeback(page);
L
Linus Torvalds 已提交
238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258
	nfs_begin_data_update(inode);
	do {
		if (count < wsize)
			wdata->args.count = count;
		wdata->args.offset = page_offset(page) + wdata->args.pgbase;

		result = NFS_PROTO(inode)->write(wdata);

		if (result < 0) {
			/* Must mark the page invalid after I/O error */
			ClearPageUptodate(page);
			goto io_error;
		}
		if (result < wdata->args.count)
			printk(KERN_WARNING "NFS: short write, count=%u, result=%d\n",
					wdata->args.count, result);

		wdata->args.offset += result;
	        wdata->args.pgbase += result;
		written += result;
		count -= result;
C
Chuck Lever 已提交
259
		nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, result);
L
Linus Torvalds 已提交
260 261 262 263 264 265 266 267 268 269
	} while (count);
	/* Update file length */
	nfs_grow_file(page, offset, written);
	/* Set the PG_uptodate flag? */
	nfs_mark_uptodate(page, offset, written);

	if (PageError(page))
		ClearPageError(page);

io_error:
270
	nfs_end_data_update(inode);
271
	end_page_writeback(page);
272
	nfs_writedata_release(wdata);
L
Linus Torvalds 已提交
273 274 275 276 277 278 279 280 281 282
	return written ? written : result;
}

static int nfs_writepage_async(struct nfs_open_context *ctx,
		struct inode *inode, struct page *page,
		unsigned int offset, unsigned int count)
{
	struct nfs_page	*req;

	req = nfs_update_request(ctx, inode, page, offset, count);
283 284
	if (IS_ERR(req))
		return PTR_ERR(req);
L
Linus Torvalds 已提交
285 286 287 288 289
	/* Update file length */
	nfs_grow_file(page, offset, count);
	/* Set the PG_uptodate flag? */
	nfs_mark_uptodate(page, offset, count);
	nfs_unlock_request(req);
290
	return 0;
L
Linus Torvalds 已提交
291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315
}

static int wb_priority(struct writeback_control *wbc)
{
	if (wbc->for_reclaim)
		return FLUSH_HIGHPRI;
	if (wbc->for_kupdate)
		return FLUSH_LOWPRI;
	return 0;
}

/*
 * Write an mmapped page to the server.
 */
int nfs_writepage(struct page *page, struct writeback_control *wbc)
{
	struct nfs_open_context *ctx;
	struct inode *inode = page->mapping->host;
	unsigned long end_index;
	unsigned offset = PAGE_CACHE_SIZE;
	loff_t i_size = i_size_read(inode);
	int inode_referenced = 0;
	int priority = wb_priority(wbc);
	int err;

C
Chuck Lever 已提交
316 317 318
	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
	nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);

L
Linus Torvalds 已提交
319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344
	/*
	 * Note: We need to ensure that we have a reference to the inode
	 *       if we are to do asynchronous writes. If not, waiting
	 *       in nfs_wait_on_request() may deadlock with clear_inode().
	 *
	 *       If igrab() fails here, then it is in any case safe to
	 *       call nfs_wb_page(), since there will be no pending writes.
	 */
	if (igrab(inode) != 0)
		inode_referenced = 1;
	end_index = i_size >> PAGE_CACHE_SHIFT;

	/* Ensure we've flushed out any previous writes */
	nfs_wb_page_priority(inode, page, priority);

	/* easy case */
	if (page->index < end_index)
		goto do_it;
	/* things got complicated... */
	offset = i_size & (PAGE_CACHE_SIZE-1);

	/* OK, are we completely out? */
	err = 0; /* potential race with truncate - ignore */
	if (page->index >= end_index+1 || !offset)
		goto out;
do_it:
345
	ctx = nfs_find_open_context(inode, NULL, FMODE_WRITE);
L
Linus Torvalds 已提交
346 347 348 349 350 351 352
	if (ctx == NULL) {
		err = -EBADF;
		goto out;
	}
	lock_kernel();
	if (!IS_SYNC(inode) && inode_referenced) {
		err = nfs_writepage_async(ctx, inode, page, 0, offset);
353
		if (!wbc->for_writepages)
T
Trond Myklebust 已提交
354
			nfs_flush_mapping(page->mapping, wbc, wb_priority(wbc));
L
Linus Torvalds 已提交
355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382
	} else {
		err = nfs_writepage_sync(ctx, inode, page, 0,
						offset, priority);
		if (err >= 0) {
			if (err != offset)
				redirty_page_for_writepage(wbc, page);
			err = 0;
		}
	}
	unlock_kernel();
	put_nfs_open_context(ctx);
out:
	unlock_page(page);
	if (inode_referenced)
		iput(inode);
	return err; 
}

/*
 * Note: causes nfs_update_request() to block on the assumption
 * 	 that the writeback is generated due to memory pressure.
 */
int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
{
	struct backing_dev_info *bdi = mapping->backing_dev_info;
	struct inode *inode = mapping->host;
	int err;

C
Chuck Lever 已提交
383 384
	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);

L
Linus Torvalds 已提交
385 386 387 388 389 390 391 392
	err = generic_writepages(mapping, wbc);
	if (err)
		return err;
	while (test_and_set_bit(BDI_write_congested, &bdi->state) != 0) {
		if (wbc->nonblocking)
			return 0;
		nfs_wait_on_write_congestion(mapping, 0);
	}
T
Trond Myklebust 已提交
393
	err = nfs_flush_mapping(mapping, wbc, wb_priority(wbc));
L
Linus Torvalds 已提交
394 395
	if (err < 0)
		goto out;
C
Chuck Lever 已提交
396
	nfs_add_stats(inode, NFSIOS_WRITEPAGES, err);
L
Linus Torvalds 已提交
397 398 399 400 401
	if (!wbc->nonblocking && wbc->sync_mode == WB_SYNC_ALL) {
		err = nfs_wait_on_requests(inode, 0, 0);
		if (err < 0)
			goto out;
	}
402
	err = nfs_commit_inode(inode, wb_priority(wbc));
L
Linus Torvalds 已提交
403 404 405 406 407 408 409
	if (err > 0) {
		wbc->nr_to_write -= err;
		err = 0;
	}
out:
	clear_bit(BDI_write_congested, &bdi->state);
	wake_up_all(&nfs_write_congestion);
410
	congestion_end(WRITE);
L
Linus Torvalds 已提交
411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431
	return err;
}

/*
 * Insert a write request into an inode
 */
static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
{
	struct nfs_inode *nfsi = NFS_I(inode);
	int error;

	error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
	BUG_ON(error == -EEXIST);
	if (error)
		return error;
	if (!nfsi->npages) {
		igrab(inode);
		nfs_begin_data_update(inode);
		if (nfs_have_delegation(inode, FMODE_WRITE))
			nfsi->change_attr++;
	}
432
	SetPagePrivate(req->wb_page);
L
Linus Torvalds 已提交
433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448
	nfsi->npages++;
	atomic_inc(&req->wb_count);
	return 0;
}

/*
 * Insert a write request into an inode
 */
static void nfs_inode_remove_request(struct nfs_page *req)
{
	struct inode *inode = req->wb_context->dentry->d_inode;
	struct nfs_inode *nfsi = NFS_I(inode);

	BUG_ON (!NFS_WBACK_BUSY(req));

	spin_lock(&nfsi->req_lock);
449
	ClearPagePrivate(req->wb_page);
L
Linus Torvalds 已提交
450 451 452 453
	radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
	nfsi->npages--;
	if (!nfsi->npages) {
		spin_unlock(&nfsi->req_lock);
454
		nfs_end_data_update(inode);
L
Linus Torvalds 已提交
455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498
		iput(inode);
	} else
		spin_unlock(&nfsi->req_lock);
	nfs_clear_request(req);
	nfs_release_request(req);
}

/*
 * Find a request
 */
static inline struct nfs_page *
_nfs_find_request(struct inode *inode, unsigned long index)
{
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_page *req;

	req = (struct nfs_page*)radix_tree_lookup(&nfsi->nfs_page_tree, index);
	if (req)
		atomic_inc(&req->wb_count);
	return req;
}

static struct nfs_page *
nfs_find_request(struct inode *inode, unsigned long index)
{
	struct nfs_page		*req;
	struct nfs_inode	*nfsi = NFS_I(inode);

	spin_lock(&nfsi->req_lock);
	req = _nfs_find_request(inode, index);
	spin_unlock(&nfsi->req_lock);
	return req;
}

/*
 * Add a request to the inode's dirty list.
 */
static void
nfs_mark_request_dirty(struct nfs_page *req)
{
	struct inode *inode = req->wb_context->dentry->d_inode;
	struct nfs_inode *nfsi = NFS_I(inode);

	spin_lock(&nfsi->req_lock);
499 500
	radix_tree_tag_set(&nfsi->nfs_page_tree,
			req->wb_index, NFS_PAGE_TAG_DIRTY);
L
Linus Torvalds 已提交
501 502 503
	nfs_list_add_request(req, &nfsi->dirty);
	nfsi->ndirty++;
	spin_unlock(&nfsi->req_lock);
504
	inc_zone_page_state(req->wb_page, NR_FILE_DIRTY);
L
Linus Torvalds 已提交
505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531
	mark_inode_dirty(inode);
}

/*
 * Check if a request is dirty
 */
static inline int
nfs_dirty_request(struct nfs_page *req)
{
	struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode);
	return !list_empty(&req->wb_list) && req->wb_list_head == &nfsi->dirty;
}

#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
/*
 * Add a request to the inode's commit list.
 */
static void
nfs_mark_request_commit(struct nfs_page *req)
{
	struct inode *inode = req->wb_context->dentry->d_inode;
	struct nfs_inode *nfsi = NFS_I(inode);

	spin_lock(&nfsi->req_lock);
	nfs_list_add_request(req, &nfsi->commit);
	nfsi->ncommit++;
	spin_unlock(&nfsi->req_lock);
532
	inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
L
Linus Torvalds 已提交
533 534 535 536 537 538 539 540 541
	mark_inode_dirty(inode);
}
#endif

/*
 * Wait for a request to complete.
 *
 * Interruptible by signals only if mounted with intr flag.
 */
542
static int nfs_wait_on_requests_locked(struct inode *inode, unsigned long idx_start, unsigned int npages)
L
Linus Torvalds 已提交
543 544 545 546 547 548 549 550 551 552 553 554 555
{
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_page *req;
	unsigned long		idx_end, next;
	unsigned int		res = 0;
	int			error;

	if (npages == 0)
		idx_end = ~0;
	else
		idx_end = idx_start + npages - 1;

	next = idx_start;
556
	while (radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree, (void **)&req, next, 1, NFS_PAGE_TAG_WRITEBACK)) {
L
Linus Torvalds 已提交
557 558 559 560
		if (req->wb_index > idx_end)
			break;

		next = req->wb_index + 1;
561
		BUG_ON(!NFS_WBACK_BUSY(req));
L
Linus Torvalds 已提交
562 563 564 565 566

		atomic_inc(&req->wb_count);
		spin_unlock(&nfsi->req_lock);
		error = nfs_wait_on_request(req);
		nfs_release_request(req);
567
		spin_lock(&nfsi->req_lock);
L
Linus Torvalds 已提交
568 569 570 571 572 573 574
		if (error < 0)
			return error;
		res++;
	}
	return res;
}

575 576 577 578 579 580 581 582 583 584 585
static int nfs_wait_on_requests(struct inode *inode, unsigned long idx_start, unsigned int npages)
{
	struct nfs_inode *nfsi = NFS_I(inode);
	int ret;

	spin_lock(&nfsi->req_lock);
	ret = nfs_wait_on_requests_locked(inode, idx_start, npages);
	spin_unlock(&nfsi->req_lock);
	return ret;
}

T
Trond Myklebust 已提交
586
static void nfs_cancel_dirty_list(struct list_head *head)
587 588 589 590 591 592 593 594 595 596
{
	struct nfs_page *req;
	while(!list_empty(head)) {
		req = nfs_list_entry(head->next);
		nfs_list_remove_request(req);
		nfs_inode_remove_request(req);
		nfs_clear_page_writeback(req);
	}
}

T
Trond Myklebust 已提交
597 598 599 600 601 602
static void nfs_cancel_commit_list(struct list_head *head)
{
	struct nfs_page *req;

	while(!list_empty(head)) {
		req = nfs_list_entry(head->next);
603
		dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
T
Trond Myklebust 已提交
604 605
		nfs_list_remove_request(req);
		nfs_inode_remove_request(req);
606
		nfs_unlock_request(req);
T
Trond Myklebust 已提交
607 608 609
	}
}

L
Linus Torvalds 已提交
610 611 612 613 614 615 616 617 618 619 620 621 622 623
/*
 * nfs_scan_dirty - Scan an inode for dirty requests
 * @inode: NFS inode to scan
 * @dst: destination list
 * @idx_start: lower bound of page->index to scan.
 * @npages: idx_start + npages sets the upper bound to scan.
 *
 * Moves requests from the inode's dirty page list.
 * The requests are *not* checked to ensure that they form a contiguous set.
 */
static int
nfs_scan_dirty(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
{
	struct nfs_inode *nfsi = NFS_I(inode);
624 625 626 627 628 629 630 631
	int res = 0;

	if (nfsi->ndirty != 0) {
		res = nfs_scan_lock_dirty(nfsi, dst, idx_start, npages);
		nfsi->ndirty -= res;
		if ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty))
			printk(KERN_ERR "NFS: desynchronized value of nfs_i.ndirty.\n");
	}
L
Linus Torvalds 已提交
632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649
	return res;
}

#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
/*
 * nfs_scan_commit - Scan an inode for commit requests
 * @inode: NFS inode to scan
 * @dst: destination list
 * @idx_start: lower bound of page->index to scan.
 * @npages: idx_start + npages sets the upper bound to scan.
 *
 * Moves requests from the inode's 'commit' request list.
 * The requests are *not* checked to ensure that they form a contiguous set.
 */
static int
nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
{
	struct nfs_inode *nfsi = NFS_I(inode);
650 651 652
	int res = 0;

	if (nfsi->ncommit != 0) {
653
		res = nfs_scan_list(nfsi, &nfsi->commit, dst, idx_start, npages);
654 655 656 657
		nfsi->ncommit -= res;
		if ((nfsi->ncommit == 0) != list_empty(&nfsi->commit))
			printk(KERN_ERR "NFS: desynchronized value of nfs_i.ncommit.\n");
	}
L
Linus Torvalds 已提交
658 659
	return res;
}
660 661 662 663 664
#else
static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
{
	return 0;
}
L
Linus Torvalds 已提交
665 666 667 668 669 670 671 672 673 674 675 676
#endif

static int nfs_wait_on_write_congestion(struct address_space *mapping, int intr)
{
	struct backing_dev_info *bdi = mapping->backing_dev_info;
	DEFINE_WAIT(wait);
	int ret = 0;

	might_sleep();

	if (!bdi_write_congested(bdi))
		return 0;
C
Chuck Lever 已提交
677 678 679

	nfs_inc_stats(mapping->host, NFSIOS_CONGESTIONWAIT);

L
Linus Torvalds 已提交
680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734
	if (intr) {
		struct rpc_clnt *clnt = NFS_CLIENT(mapping->host);
		sigset_t oldset;

		rpc_clnt_sigmask(clnt, &oldset);
		prepare_to_wait(&nfs_write_congestion, &wait, TASK_INTERRUPTIBLE);
		if (bdi_write_congested(bdi)) {
			if (signalled())
				ret = -ERESTARTSYS;
			else
				schedule();
		}
		rpc_clnt_sigunmask(clnt, &oldset);
	} else {
		prepare_to_wait(&nfs_write_congestion, &wait, TASK_UNINTERRUPTIBLE);
		if (bdi_write_congested(bdi))
			schedule();
	}
	finish_wait(&nfs_write_congestion, &wait);
	return ret;
}


/*
 * Try to update any existing write request, or create one if there is none.
 * In order to match, the request's credentials must match those of
 * the calling process.
 *
 * Note: Should always be called with the Page Lock held!
 */
static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
		struct inode *inode, struct page *page,
		unsigned int offset, unsigned int bytes)
{
	struct nfs_server *server = NFS_SERVER(inode);
	struct nfs_inode *nfsi = NFS_I(inode);
	struct nfs_page		*req, *new = NULL;
	unsigned long		rqend, end;

	end = offset + bytes;

	if (nfs_wait_on_write_congestion(page->mapping, server->flags & NFS_MOUNT_INTR))
		return ERR_PTR(-ERESTARTSYS);
	for (;;) {
		/* Loop over all inode entries and see if we find
		 * A request for the page we wish to update
		 */
		spin_lock(&nfsi->req_lock);
		req = _nfs_find_request(inode, page->index);
		if (req) {
			if (!nfs_lock_request_dontget(req)) {
				int error;
				spin_unlock(&nfsi->req_lock);
				error = nfs_wait_on_request(req);
				nfs_release_request(req);
N
Neil Brown 已提交
735 736 737
				if (error < 0) {
					if (new)
						nfs_release_request(new);
L
Linus Torvalds 已提交
738
					return ERR_PTR(error);
N
Neil Brown 已提交
739
				}
L
Linus Torvalds 已提交
740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832
				continue;
			}
			spin_unlock(&nfsi->req_lock);
			if (new)
				nfs_release_request(new);
			break;
		}

		if (new) {
			int error;
			nfs_lock_request_dontget(new);
			error = nfs_inode_add_request(inode, new);
			if (error) {
				spin_unlock(&nfsi->req_lock);
				nfs_unlock_request(new);
				return ERR_PTR(error);
			}
			spin_unlock(&nfsi->req_lock);
			nfs_mark_request_dirty(new);
			return new;
		}
		spin_unlock(&nfsi->req_lock);

		new = nfs_create_request(ctx, inode, page, offset, bytes);
		if (IS_ERR(new))
			return new;
	}

	/* We have a request for our page.
	 * If the creds don't match, or the
	 * page addresses don't match,
	 * tell the caller to wait on the conflicting
	 * request.
	 */
	rqend = req->wb_offset + req->wb_bytes;
	if (req->wb_context != ctx
	    || req->wb_page != page
	    || !nfs_dirty_request(req)
	    || offset > rqend || end < req->wb_offset) {
		nfs_unlock_request(req);
		return ERR_PTR(-EBUSY);
	}

	/* Okay, the request matches. Update the region */
	if (offset < req->wb_offset) {
		req->wb_offset = offset;
		req->wb_pgbase = offset;
		req->wb_bytes = rqend - req->wb_offset;
	}

	if (end > rqend)
		req->wb_bytes = end - req->wb_offset;

	return req;
}

int nfs_flush_incompatible(struct file *file, struct page *page)
{
	struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
	struct inode	*inode = page->mapping->host;
	struct nfs_page	*req;
	int		status = 0;
	/*
	 * Look for a request corresponding to this page. If there
	 * is one, and it belongs to another file, we flush it out
	 * before we try to copy anything into the page. Do this
	 * due to the lack of an ACCESS-type call in NFSv2.
	 * Also do the same if we find a request from an existing
	 * dropped page.
	 */
	req = nfs_find_request(inode, page->index);
	if (req) {
		if (req->wb_page != page || ctx != req->wb_context)
			status = nfs_wb_page(inode, page);
		nfs_release_request(req);
	}
	return (status < 0) ? status : 0;
}

/*
 * Update and possibly write a cached page of an NFS file.
 *
 * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
 * things with a page scheduled for an RPC call (e.g. invalidate it).
 */
int nfs_updatepage(struct file *file, struct page *page,
		unsigned int offset, unsigned int count)
{
	struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
	struct inode	*inode = page->mapping->host;
	struct nfs_page	*req;
	int		status = 0;

C
Chuck Lever 已提交
833 834
	nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);

L
Linus Torvalds 已提交
835
	dprintk("NFS:      nfs_updatepage(%s/%s %d@%Ld)\n",
836 837 838
		file->f_dentry->d_parent->d_name.name,
		file->f_dentry->d_name.name, count,
		(long long)(page_offset(page) +offset));
L
Linus Torvalds 已提交
839 840 841 842 843 844 845 846 847 848 849 850 851 852 853

	if (IS_SYNC(inode)) {
		status = nfs_writepage_sync(ctx, inode, page, offset, count, 0);
		if (status > 0) {
			if (offset == 0 && status == PAGE_CACHE_SIZE)
				SetPageUptodate(page);
			return 0;
		}
		return status;
	}

	/* If we're not using byte range locks, and we know the page
	 * is entirely in cache, it may be more efficient to avoid
	 * fragmenting write requests.
	 */
854
	if (PageUptodate(page) && inode->i_flock == NULL && !(file->f_mode & O_SYNC)) {
L
Linus Torvalds 已提交
855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924
		loff_t end_offs = i_size_read(inode) - 1;
		unsigned long end_index = end_offs >> PAGE_CACHE_SHIFT;

		count += offset;
		offset = 0;
		if (unlikely(end_offs < 0)) {
			/* Do nothing */
		} else if (page->index == end_index) {
			unsigned int pglen;
			pglen = (unsigned int)(end_offs & (PAGE_CACHE_SIZE-1)) + 1;
			if (count < pglen)
				count = pglen;
		} else if (page->index < end_index)
			count = PAGE_CACHE_SIZE;
	}

	/*
	 * Try to find an NFS request corresponding to this page
	 * and update it.
	 * If the existing request cannot be updated, we must flush
	 * it out now.
	 */
	do {
		req = nfs_update_request(ctx, inode, page, offset, count);
		status = (IS_ERR(req)) ? PTR_ERR(req) : 0;
		if (status != -EBUSY)
			break;
		/* Request could not be updated. Flush it out and try again */
		status = nfs_wb_page(inode, page);
	} while (status >= 0);
	if (status < 0)
		goto done;

	status = 0;

	/* Update file length */
	nfs_grow_file(page, offset, count);
	/* Set the PG_uptodate flag? */
	nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
	nfs_unlock_request(req);
done:
        dprintk("NFS:      nfs_updatepage returns %d (isize %Ld)\n",
			status, (long long)i_size_read(inode));
	if (status < 0)
		ClearPageUptodate(page);
	return status;
}

static void nfs_writepage_release(struct nfs_page *req)
{
	end_page_writeback(req->wb_page);

#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
	if (!PageError(req->wb_page)) {
		if (NFS_NEED_RESCHED(req)) {
			nfs_mark_request_dirty(req);
			goto out;
		} else if (NFS_NEED_COMMIT(req)) {
			nfs_mark_request_commit(req);
			goto out;
		}
	}
	nfs_inode_remove_request(req);

out:
	nfs_clear_commit(req);
	nfs_clear_reschedule(req);
#else
	nfs_inode_remove_request(req);
#endif
925
	nfs_clear_page_writeback(req);
L
Linus Torvalds 已提交
926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943
}

static inline int flush_task_priority(int how)
{
	switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
		case FLUSH_HIGHPRI:
			return RPC_PRIORITY_HIGH;
		case FLUSH_LOWPRI:
			return RPC_PRIORITY_LOW;
	}
	return RPC_PRIORITY_NORMAL;
}

/*
 * Set up the argument/result storage required for the RPC call.
 */
static void nfs_write_rpcsetup(struct nfs_page *req,
		struct nfs_write_data *data,
944
		const struct rpc_call_ops *call_ops,
L
Linus Torvalds 已提交
945 946 947 948
		unsigned int count, unsigned int offset,
		int how)
{
	struct inode		*inode;
949
	int flags;
L
Linus Torvalds 已提交
950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967

	/* Set up the RPC argument and reply structs
	 * NB: take care not to mess about with data->commit et al. */

	data->req = req;
	data->inode = inode = req->wb_context->dentry->d_inode;
	data->cred = req->wb_context->cred;

	data->args.fh     = NFS_FH(inode);
	data->args.offset = req_offset(req) + offset;
	data->args.pgbase = req->wb_pgbase + offset;
	data->args.pages  = data->pagevec;
	data->args.count  = count;
	data->args.context = req->wb_context;

	data->res.fattr   = &data->fattr;
	data->res.count   = count;
	data->res.verf    = &data->verf;
968
	nfs_fattr_init(&data->fattr);
L
Linus Torvalds 已提交
969

970 971 972
	/* Set up the initial task struct.  */
	flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
	rpc_init_task(&data->task, NFS_CLIENT(inode), flags, call_ops, data);
L
Linus Torvalds 已提交
973 974 975 976 977 978
	NFS_PROTO(inode)->write_setup(data, how);

	data->task.tk_priority = flush_task_priority(how);
	data->task.tk_cookie = (unsigned long)inode;

	dprintk("NFS: %4d initiated write call (req %s/%Ld, %u bytes @ offset %Lu)\n",
979
		data->task.tk_pid,
L
Linus Torvalds 已提交
980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999
		inode->i_sb->s_id,
		(long long)NFS_FILEID(inode),
		count,
		(unsigned long long)data->args.offset);
}

static void nfs_execute_write(struct nfs_write_data *data)
{
	struct rpc_clnt *clnt = NFS_CLIENT(data->inode);
	sigset_t oldset;

	rpc_clnt_sigmask(clnt, &oldset);
	rpc_execute(&data->task);
	rpc_clnt_sigunmask(clnt, &oldset);
}

/*
 * Generate multiple small requests to write out a single
 * contiguous dirty area on one page.
 */
T
Trond Myklebust 已提交
1000
static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
L
Linus Torvalds 已提交
1001 1002 1003 1004
{
	struct nfs_page *req = nfs_list_entry(head->next);
	struct page *page = req->wb_page;
	struct nfs_write_data *data;
1005 1006
	size_t wsize = NFS_SERVER(inode)->wsize, nbytes;
	unsigned int offset;
L
Linus Torvalds 已提交
1007 1008 1009 1010 1011 1012
	int requests = 0;
	LIST_HEAD(list);

	nfs_list_remove_request(req);

	nbytes = req->wb_bytes;
1013 1014 1015 1016
	do {
		size_t len = min(nbytes, wsize);

		data = nfs_writedata_alloc(len);
L
Linus Torvalds 已提交
1017 1018 1019 1020
		if (!data)
			goto out_bad;
		list_add(&data->pages, &list);
		requests++;
1021 1022
		nbytes -= len;
	} while (nbytes != 0);
L
Linus Torvalds 已提交
1023 1024 1025
	atomic_set(&req->wb_complete, requests);

	ClearPageError(page);
1026
	set_page_writeback(page);
L
Linus Torvalds 已提交
1027 1028 1029 1030 1031 1032 1033 1034 1035
	offset = 0;
	nbytes = req->wb_bytes;
	do {
		data = list_entry(list.next, struct nfs_write_data, pages);
		list_del_init(&data->pages);

		data->pagevec[0] = page;

		if (nbytes > wsize) {
1036 1037
			nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
					wsize, offset, how);
L
Linus Torvalds 已提交
1038 1039 1040
			offset += wsize;
			nbytes -= wsize;
		} else {
1041 1042
			nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
					nbytes, offset, how);
L
Linus Torvalds 已提交
1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053
			nbytes = 0;
		}
		nfs_execute_write(data);
	} while (nbytes != 0);

	return 0;

out_bad:
	while (!list_empty(&list)) {
		data = list_entry(list.next, struct nfs_write_data, pages);
		list_del(&data->pages);
1054
		nfs_writedata_release(data);
L
Linus Torvalds 已提交
1055 1056
	}
	nfs_mark_request_dirty(req);
1057
	nfs_clear_page_writeback(req);
L
Linus Torvalds 已提交
1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068
	return -ENOMEM;
}

/*
 * Create an RPC task for the given write request and kick it.
 * The page must have been locked by the caller.
 *
 * It may happen that the page we're passed is not marked dirty.
 * This is the case if nfs_updatepage detects a conflicting request
 * that has been written but not committed.
 */
T
Trond Myklebust 已提交
1069
static int nfs_flush_one(struct inode *inode, struct list_head *head, int how)
L
Linus Torvalds 已提交
1070 1071 1072 1073 1074 1075
{
	struct nfs_page		*req;
	struct page		**pages;
	struct nfs_write_data	*data;
	unsigned int		count;

1076
	data = nfs_writedata_alloc(NFS_SERVER(inode)->wsize);
L
Linus Torvalds 已提交
1077 1078 1079 1080 1081 1082 1083 1084 1085 1086
	if (!data)
		goto out_bad;

	pages = data->pagevec;
	count = 0;
	while (!list_empty(head)) {
		req = nfs_list_entry(head->next);
		nfs_list_remove_request(req);
		nfs_list_add_request(req, &data->pages);
		ClearPageError(req->wb_page);
1087
		set_page_writeback(req->wb_page);
L
Linus Torvalds 已提交
1088 1089 1090 1091 1092 1093
		*pages++ = req->wb_page;
		count += req->wb_bytes;
	}
	req = nfs_list_entry(data->pages.next);

	/* Set up the argument struct */
1094
	nfs_write_rpcsetup(req, data, &nfs_write_full_ops, count, 0, how);
L
Linus Torvalds 已提交
1095 1096 1097 1098 1099 1100 1101 1102

	nfs_execute_write(data);
	return 0;
 out_bad:
	while (!list_empty(head)) {
		struct nfs_page *req = nfs_list_entry(head->next);
		nfs_list_remove_request(req);
		nfs_mark_request_dirty(req);
1103
		nfs_clear_page_writeback(req);
L
Linus Torvalds 已提交
1104 1105 1106 1107
	}
	return -ENOMEM;
}

T
Trond Myklebust 已提交
1108
static int nfs_flush_list(struct inode *inode, struct list_head *head, int npages, int how)
L
Linus Torvalds 已提交
1109 1110
{
	LIST_HEAD(one_request);
T
Trond Myklebust 已提交
1111 1112 1113 1114 1115
	int (*flush_one)(struct inode *, struct list_head *, int);
	struct nfs_page	*req;
	int wpages = NFS_SERVER(inode)->wpages;
	int wsize = NFS_SERVER(inode)->wsize;
	int error;
L
Linus Torvalds 已提交
1116

T
Trond Myklebust 已提交
1117 1118 1119 1120 1121 1122 1123 1124 1125 1126
	flush_one = nfs_flush_one;
	if (wsize < PAGE_CACHE_SIZE)
		flush_one = nfs_flush_multi;
	/* For single writes, FLUSH_STABLE is more efficient */
	if (npages <= wpages && npages == NFS_I(inode)->npages
			&& nfs_list_entry(head->next)->wb_bytes <= wsize)
		how |= FLUSH_STABLE;

	do {
		nfs_coalesce_requests(head, &one_request, wpages);
L
Linus Torvalds 已提交
1127
		req = nfs_list_entry(one_request.next);
T
Trond Myklebust 已提交
1128
		error = flush_one(inode, &one_request, how);
L
Linus Torvalds 已提交
1129
		if (error < 0)
T
Trond Myklebust 已提交
1130 1131 1132 1133
			goto out_err;
	} while (!list_empty(head));
	return 0;
out_err:
L
Linus Torvalds 已提交
1134 1135 1136 1137
	while (!list_empty(head)) {
		req = nfs_list_entry(head->next);
		nfs_list_remove_request(req);
		nfs_mark_request_dirty(req);
1138
		nfs_clear_page_writeback(req);
L
Linus Torvalds 已提交
1139 1140 1141 1142 1143 1144 1145
	}
	return error;
}

/*
 * Handle a write reply that flushed part of a page.
 */
1146
static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
L
Linus Torvalds 已提交
1147
{
1148
	struct nfs_write_data	*data = calldata;
L
Linus Torvalds 已提交
1149 1150 1151 1152 1153 1154 1155 1156 1157
	struct nfs_page		*req = data->req;
	struct page		*page = req->wb_page;

	dprintk("NFS: write (%s/%Ld %d@%Ld)",
		req->wb_context->dentry->d_inode->i_sb->s_id,
		(long long)NFS_FILEID(req->wb_context->dentry->d_inode),
		req->wb_bytes,
		(long long)req_offset(req));

1158 1159 1160 1161
	if (nfs_writeback_done(task, data) != 0)
		return;

	if (task->tk_status < 0) {
L
Linus Torvalds 已提交
1162 1163
		ClearPageUptodate(page);
		SetPageError(page);
1164 1165
		req->wb_context->error = task->tk_status;
		dprintk(", error = %d\n", task->tk_status);
L
Linus Torvalds 已提交
1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185
	} else {
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
		if (data->verf.committed < NFS_FILE_SYNC) {
			if (!NFS_NEED_COMMIT(req)) {
				nfs_defer_commit(req);
				memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
				dprintk(" defer commit\n");
			} else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
				nfs_defer_reschedule(req);
				dprintk(" server reboot detected\n");
			}
		} else
#endif
			dprintk(" OK\n");
	}

	if (atomic_dec_and_test(&req->wb_complete))
		nfs_writepage_release(req);
}

1186 1187 1188 1189 1190
static const struct rpc_call_ops nfs_write_partial_ops = {
	.rpc_call_done = nfs_writeback_done_partial,
	.rpc_release = nfs_writedata_release,
};

L
Linus Torvalds 已提交
1191 1192 1193 1194 1195 1196 1197
/*
 * Handle a write reply that flushes a whole page.
 *
 * FIXME: There is an inherent race with invalidate_inode_pages and
 *	  writebacks since the page->count is kept > 1 for as long
 *	  as the page has a write request pending.
 */
1198
static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
L
Linus Torvalds 已提交
1199
{
1200
	struct nfs_write_data	*data = calldata;
L
Linus Torvalds 已提交
1201 1202 1203
	struct nfs_page		*req;
	struct page		*page;

1204 1205 1206
	if (nfs_writeback_done(task, data) != 0)
		return;

L
Linus Torvalds 已提交
1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218
	/* Update attributes as result of writeback. */
	while (!list_empty(&data->pages)) {
		req = nfs_list_entry(data->pages.next);
		nfs_list_remove_request(req);
		page = req->wb_page;

		dprintk("NFS: write (%s/%Ld %d@%Ld)",
			req->wb_context->dentry->d_inode->i_sb->s_id,
			(long long)NFS_FILEID(req->wb_context->dentry->d_inode),
			req->wb_bytes,
			(long long)req_offset(req));

1219
		if (task->tk_status < 0) {
L
Linus Torvalds 已提交
1220 1221
			ClearPageUptodate(page);
			SetPageError(page);
1222
			req->wb_context->error = task->tk_status;
L
Linus Torvalds 已提交
1223 1224
			end_page_writeback(page);
			nfs_inode_remove_request(req);
1225
			dprintk(", error = %d\n", task->tk_status);
L
Linus Torvalds 已提交
1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242
			goto next;
		}
		end_page_writeback(page);

#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
		if (data->args.stable != NFS_UNSTABLE || data->verf.committed == NFS_FILE_SYNC) {
			nfs_inode_remove_request(req);
			dprintk(" OK\n");
			goto next;
		}
		memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
		nfs_mark_request_commit(req);
		dprintk(" marked for commit\n");
#else
		nfs_inode_remove_request(req);
#endif
	next:
1243
		nfs_clear_page_writeback(req);
L
Linus Torvalds 已提交
1244 1245 1246
	}
}

1247 1248 1249 1250 1251 1252
static const struct rpc_call_ops nfs_write_full_ops = {
	.rpc_call_done = nfs_writeback_done_full,
	.rpc_release = nfs_writedata_release,
};


L
Linus Torvalds 已提交
1253 1254 1255
/*
 * This function is called when the WRITE call is complete.
 */
1256
int nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
L
Linus Torvalds 已提交
1257 1258 1259
{
	struct nfs_writeargs	*argp = &data->args;
	struct nfs_writeres	*resp = &data->res;
1260
	int status;
L
Linus Torvalds 已提交
1261 1262 1263 1264

	dprintk("NFS: %4d nfs_writeback_done (status %d)\n",
		task->tk_pid, task->tk_status);

1265 1266 1267 1268 1269 1270 1271
	/*
	 * ->write_done will attempt to use post-op attributes to detect
	 * conflicting writes by other clients.  A strict interpretation
	 * of close-to-open would allow us to continue caching even if
	 * another writer had changed the file, but some applications
	 * depend on tighter cache coherency when writing.
	 */
1272 1273 1274
	status = NFS_PROTO(data->inode)->write_done(task, data);
	if (status != 0)
		return status;
C
Chuck Lever 已提交
1275 1276
	nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);

L
Linus Torvalds 已提交
1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
	if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
		/* We tried a write call, but the server did not
		 * commit data to stable storage even though we
		 * requested it.
		 * Note: There is a known bug in Tru64 < 5.0 in which
		 *	 the server reports NFS_DATA_SYNC, but performs
		 *	 NFS_FILE_SYNC. We therefore implement this checking
		 *	 as a dprintk() in order to avoid filling syslog.
		 */
		static unsigned long    complain;

		if (time_before(complain, jiffies)) {
			dprintk("NFS: faulty NFS server %s:"
				" (committed = %d) != (stable = %d)\n",
1292
				NFS_SERVER(data->inode)->nfs_client->cl_hostname,
L
Linus Torvalds 已提交
1293 1294 1295 1296 1297 1298 1299 1300 1301
				resp->verf->committed, argp->stable);
			complain = jiffies + 300 * HZ;
		}
	}
#endif
	/* Is this a short write? */
	if (task->tk_status >= 0 && resp->count < argp->count) {
		static unsigned long    complain;

C
Chuck Lever 已提交
1302 1303
		nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);

L
Linus Torvalds 已提交
1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318
		/* Has the server at least made some progress? */
		if (resp->count != 0) {
			/* Was this an NFSv2 write or an NFSv3 stable write? */
			if (resp->verf->committed != NFS_UNSTABLE) {
				/* Resend from where the server left off */
				argp->offset += resp->count;
				argp->pgbase += resp->count;
				argp->count -= resp->count;
			} else {
				/* Resend as a stable write in order to avoid
				 * headaches in the case of a server crash.
				 */
				argp->stable = NFS_FILE_SYNC;
			}
			rpc_restart_call(task);
1319
			return -EAGAIN;
L
Linus Torvalds 已提交
1320 1321 1322 1323 1324 1325 1326 1327 1328 1329
		}
		if (time_before(complain, jiffies)) {
			printk(KERN_WARNING
			       "NFS: Server wrote zero bytes, expected %u.\n",
					argp->count);
			complain = jiffies + 300 * HZ;
		}
		/* Can't do anything about it except throw an error. */
		task->tk_status = -EIO;
	}
1330
	return 0;
L
Linus Torvalds 已提交
1331 1332 1333 1334
}


#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1335
void nfs_commit_release(void *wdata)
L
Linus Torvalds 已提交
1336 1337 1338 1339 1340 1341 1342 1343
{
	nfs_commit_free(wdata);
}

/*
 * Set up the argument/result storage required for the RPC call.
 */
static void nfs_commit_rpcsetup(struct list_head *head,
1344 1345
		struct nfs_write_data *data,
		int how)
L
Linus Torvalds 已提交
1346
{
1347
	struct nfs_page		*first;
L
Linus Torvalds 已提交
1348
	struct inode		*inode;
1349
	int flags;
L
Linus Torvalds 已提交
1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361

	/* Set up the RPC argument and reply structs
	 * NB: take care not to mess about with data->commit et al. */

	list_splice_init(head, &data->pages);
	first = nfs_list_entry(data->pages.next);
	inode = first->wb_context->dentry->d_inode;

	data->inode	  = inode;
	data->cred	  = first->wb_context->cred;

	data->args.fh     = NFS_FH(data->inode);
1362 1363 1364 1365
	/* Note: we always request a commit of the entire inode */
	data->args.offset = 0;
	data->args.count  = 0;
	data->res.count   = 0;
L
Linus Torvalds 已提交
1366 1367
	data->res.fattr   = &data->fattr;
	data->res.verf    = &data->verf;
1368
	nfs_fattr_init(&data->fattr);
1369 1370 1371 1372

	/* Set up the initial task struct.  */
	flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
	rpc_init_task(&data->task, NFS_CLIENT(inode), flags, &nfs_commit_ops, data);
L
Linus Torvalds 已提交
1373 1374 1375 1376 1377
	NFS_PROTO(inode)->commit_setup(data, how);

	data->task.tk_priority = flush_task_priority(how);
	data->task.tk_cookie = (unsigned long)inode;
	
1378
	dprintk("NFS: %4d initiated commit call\n", data->task.tk_pid);
L
Linus Torvalds 已提交
1379 1380 1381 1382 1383 1384
}

/*
 * Commit dirty pages
 */
static int
1385
nfs_commit_list(struct inode *inode, struct list_head *head, int how)
L
Linus Torvalds 已提交
1386 1387 1388 1389
{
	struct nfs_write_data	*data;
	struct nfs_page         *req;

1390
	data = nfs_commit_alloc();
L
Linus Torvalds 已提交
1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404

	if (!data)
		goto out_bad;

	/* Set up the argument struct */
	nfs_commit_rpcsetup(head, data, how);

	nfs_execute_write(data);
	return 0;
 out_bad:
	while (!list_empty(head)) {
		req = nfs_list_entry(head->next);
		nfs_list_remove_request(req);
		nfs_mark_request_commit(req);
T
Trond Myklebust 已提交
1405
		dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1406
		nfs_clear_page_writeback(req);
L
Linus Torvalds 已提交
1407 1408 1409 1410 1411 1412 1413
	}
	return -ENOMEM;
}

/*
 * COMMIT call returned
 */
1414
static void nfs_commit_done(struct rpc_task *task, void *calldata)
L
Linus Torvalds 已提交
1415
{
1416
	struct nfs_write_data	*data = calldata;
L
Linus Torvalds 已提交
1417 1418 1419 1420 1421
	struct nfs_page		*req;

        dprintk("NFS: %4d nfs_commit_done (status %d)\n",
                                task->tk_pid, task->tk_status);

1422 1423 1424 1425
	/* Call the NFS version-specific code */
	if (NFS_PROTO(data->inode)->commit_done(task, data) != 0)
		return;

L
Linus Torvalds 已提交
1426 1427 1428
	while (!list_empty(&data->pages)) {
		req = nfs_list_entry(data->pages.next);
		nfs_list_remove_request(req);
1429
		dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
L
Linus Torvalds 已提交
1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454

		dprintk("NFS: commit (%s/%Ld %d@%Ld)",
			req->wb_context->dentry->d_inode->i_sb->s_id,
			(long long)NFS_FILEID(req->wb_context->dentry->d_inode),
			req->wb_bytes,
			(long long)req_offset(req));
		if (task->tk_status < 0) {
			req->wb_context->error = task->tk_status;
			nfs_inode_remove_request(req);
			dprintk(", error = %d\n", task->tk_status);
			goto next;
		}

		/* Okay, COMMIT succeeded, apparently. Check the verifier
		 * returned by the server against all stored verfs. */
		if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
			/* We have a match */
			nfs_inode_remove_request(req);
			dprintk(" OK\n");
			goto next;
		}
		/* We have a mismatch. Write the page again */
		dprintk(" mismatch\n");
		nfs_mark_request_dirty(req);
	next:
1455
		nfs_clear_page_writeback(req);
L
Linus Torvalds 已提交
1456 1457
	}
}
1458 1459 1460 1461 1462

static const struct rpc_call_ops nfs_commit_ops = {
	.rpc_call_done = nfs_commit_done,
	.rpc_release = nfs_commit_release,
};
1463 1464 1465 1466 1467
#else
static inline int nfs_commit_list(struct inode *inode, struct list_head *head, int how)
{
	return 0;
}
L
Linus Torvalds 已提交
1468 1469
#endif

T
Trond Myklebust 已提交
1470
static int nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how)
L
Linus Torvalds 已提交
1471
{
T
Trond Myklebust 已提交
1472
	struct nfs_inode *nfsi = NFS_I(mapping->host);
L
Linus Torvalds 已提交
1473
	LIST_HEAD(head);
T
Trond Myklebust 已提交
1474 1475
	pgoff_t index = wbc->range_start >> PAGE_CACHE_SHIFT;
	unsigned long npages = 1 + (wbc->range_end >> PAGE_CACHE_SHIFT) - index;
T
Trond Myklebust 已提交
1476
	int res;
L
Linus Torvalds 已提交
1477 1478

	spin_lock(&nfsi->req_lock);
T
Trond Myklebust 已提交
1479
	res = nfs_scan_dirty(mapping->host, &head, index, npages);
L
Linus Torvalds 已提交
1480
	spin_unlock(&nfsi->req_lock);
1481
	if (res) {
T
Trond Myklebust 已提交
1482
		int error = nfs_flush_list(mapping->host, &head, res, how);
T
Trond Myklebust 已提交
1483 1484
		if (error < 0)
			return error;
T
Trond Myklebust 已提交
1485
		wbc->nr_to_write -= res;
1486
	}
L
Linus Torvalds 已提交
1487 1488 1489 1490
	return res;
}

#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1491
int nfs_commit_inode(struct inode *inode, int how)
L
Linus Torvalds 已提交
1492 1493 1494
{
	struct nfs_inode *nfsi = NFS_I(inode);
	LIST_HEAD(head);
T
Trond Myklebust 已提交
1495
	int res;
L
Linus Torvalds 已提交
1496 1497

	spin_lock(&nfsi->req_lock);
1498 1499
	res = nfs_scan_commit(inode, &head, 0, 0);
	spin_unlock(&nfsi->req_lock);
L
Linus Torvalds 已提交
1500
	if (res) {
T
Trond Myklebust 已提交
1501
		int error = nfs_commit_list(inode, &head, how);
1502 1503 1504
		if (error < 0)
			return error;
	}
L
Linus Torvalds 已提交
1505 1506 1507 1508
	return res;
}
#endif

1509 1510
int nfs_sync_inode_wait(struct inode *inode, unsigned long idx_start,
		unsigned int npages, int how)
L
Linus Torvalds 已提交
1511
{
1512 1513
	struct nfs_inode *nfsi = NFS_I(inode);
	LIST_HEAD(head);
1514
	int nocommit = how & FLUSH_NOCOMMIT;
1515
	int pages, ret;
L
Linus Torvalds 已提交
1516

1517 1518
	how &= ~FLUSH_NOCOMMIT;
	spin_lock(&nfsi->req_lock);
L
Linus Torvalds 已提交
1519
	do {
1520 1521
		ret = nfs_wait_on_requests_locked(inode, idx_start, npages);
		if (ret != 0)
1522
			continue;
1523 1524 1525
		pages = nfs_scan_dirty(inode, &head, idx_start, npages);
		if (pages != 0) {
			spin_unlock(&nfsi->req_lock);
1526
			if (how & FLUSH_INVALIDATE) {
T
Trond Myklebust 已提交
1527
				nfs_cancel_dirty_list(&head);
1528 1529
				ret = pages;
			} else
1530
				ret = nfs_flush_list(inode, &head, pages, how);
1531 1532 1533 1534 1535
			spin_lock(&nfsi->req_lock);
			continue;
		}
		if (nocommit)
			break;
1536
		pages = nfs_scan_commit(inode, &head, idx_start, npages);
1537 1538
		if (pages == 0)
			break;
1539 1540
		if (how & FLUSH_INVALIDATE) {
			spin_unlock(&nfsi->req_lock);
T
Trond Myklebust 已提交
1541
			nfs_cancel_commit_list(&head);
1542
			ret = pages;
1543 1544 1545 1546
			spin_lock(&nfsi->req_lock);
			continue;
		}
		pages += nfs_scan_commit(inode, &head, 0, 0);
1547 1548 1549 1550 1551 1552
		spin_unlock(&nfsi->req_lock);
		ret = nfs_commit_list(inode, &head, how);
		spin_lock(&nfsi->req_lock);
	} while (ret >= 0);
	spin_unlock(&nfsi->req_lock);
	return ret;
L
Linus Torvalds 已提交
1553 1554
}

D
David Howells 已提交
1555
int __init nfs_init_writepagecache(void)
L
Linus Torvalds 已提交
1556 1557 1558 1559 1560 1561 1562 1563
{
	nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
					     sizeof(struct nfs_write_data),
					     0, SLAB_HWCACHE_ALIGN,
					     NULL, NULL);
	if (nfs_wdata_cachep == NULL)
		return -ENOMEM;

1564 1565
	nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
						     nfs_wdata_cachep);
L
Linus Torvalds 已提交
1566 1567 1568
	if (nfs_wdata_mempool == NULL)
		return -ENOMEM;

1569 1570
	nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
						      nfs_wdata_cachep);
L
Linus Torvalds 已提交
1571 1572 1573 1574 1575 1576
	if (nfs_commit_mempool == NULL)
		return -ENOMEM;

	return 0;
}

1577
void nfs_destroy_writepagecache(void)
L
Linus Torvalds 已提交
1578 1579 1580
{
	mempool_destroy(nfs_commit_mempool);
	mempool_destroy(nfs_wdata_mempool);
1581
	kmem_cache_destroy(nfs_wdata_cachep);
L
Linus Torvalds 已提交
1582 1583
}