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1/*
2 * linux/fs/nfs/write.c
3 *
4 * Write file data over NFS.
5 *
6 * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
7 */
8
9#include <linux/types.h>
10#include <linux/slab.h>
11#include <linux/mm.h>
12#include <linux/pagemap.h>
13#include <linux/file.h>
14#include <linux/writeback.h>
15#include <linux/swap.h>
16#include <linux/migrate.h>
17
18#include <linux/sunrpc/clnt.h>
19#include <linux/nfs_fs.h>
20#include <linux/nfs_mount.h>
21#include <linux/nfs_page.h>
22#include <linux/backing-dev.h>
23#include <linux/export.h>
24
25#include <asm/uaccess.h>
26
27#include "delegation.h"
28#include "internal.h"
29#include "iostat.h"
30#include "nfs4_fs.h"
31#include "fscache.h"
32#include "pnfs.h"
33
34#define NFSDBG_FACILITY NFSDBG_PAGECACHE
35
36#define MIN_POOL_WRITE (32)
37#define MIN_POOL_COMMIT (4)
38
39/*
40 * Local function declarations
41 */
42static void nfs_redirty_request(struct nfs_page *req);
43static const struct rpc_call_ops nfs_write_common_ops;
44static const struct rpc_call_ops nfs_commit_ops;
45static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
46static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
47
48static struct kmem_cache *nfs_wdata_cachep;
49static mempool_t *nfs_wdata_mempool;
50static struct kmem_cache *nfs_cdata_cachep;
51static mempool_t *nfs_commit_mempool;
52
53struct nfs_commit_data *nfs_commitdata_alloc(void)
54{
55 struct nfs_commit_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
56
57 if (p) {
58 memset(p, 0, sizeof(*p));
59 INIT_LIST_HEAD(&p->pages);
60 }
61 return p;
62}
63EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
64
65void nfs_commit_free(struct nfs_commit_data *p)
66{
67 mempool_free(p, nfs_commit_mempool);
68}
69EXPORT_SYMBOL_GPL(nfs_commit_free);
70
71struct nfs_write_header *nfs_writehdr_alloc(void)
72{
73 struct nfs_write_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
74
75 if (p) {
76 struct nfs_pgio_header *hdr = &p->header;
77
78 memset(p, 0, sizeof(*p));
79 INIT_LIST_HEAD(&hdr->pages);
80 INIT_LIST_HEAD(&hdr->rpc_list);
81 spin_lock_init(&hdr->lock);
82 atomic_set(&hdr->refcnt, 0);
83 hdr->verf = &p->verf;
84 }
85 return p;
86}
87
88static struct nfs_write_data *nfs_writedata_alloc(struct nfs_pgio_header *hdr,
89 unsigned int pagecount)
90{
91 struct nfs_write_data *data, *prealloc;
92
93 prealloc = &container_of(hdr, struct nfs_write_header, header)->rpc_data;
94 if (prealloc->header == NULL)
95 data = prealloc;
96 else
97 data = kzalloc(sizeof(*data), GFP_KERNEL);
98 if (!data)
99 goto out;
100
101 if (nfs_pgarray_set(&data->pages, pagecount)) {
102 data->header = hdr;
103 atomic_inc(&hdr->refcnt);
104 } else {
105 if (data != prealloc)
106 kfree(data);
107 data = NULL;
108 }
109out:
110 return data;
111}
112
113void nfs_writehdr_free(struct nfs_pgio_header *hdr)
114{
115 struct nfs_write_header *whdr = container_of(hdr, struct nfs_write_header, header);
116 mempool_free(whdr, nfs_wdata_mempool);
117}
118
119void nfs_writedata_release(struct nfs_write_data *wdata)
120{
121 struct nfs_pgio_header *hdr = wdata->header;
122 struct nfs_write_header *write_header = container_of(hdr, struct nfs_write_header, header);
123
124 put_nfs_open_context(wdata->args.context);
125 if (wdata->pages.pagevec != wdata->pages.page_array)
126 kfree(wdata->pages.pagevec);
127 if (wdata != &write_header->rpc_data)
128 kfree(wdata);
129 else
130 wdata->header = NULL;
131 if (atomic_dec_and_test(&hdr->refcnt))
132 hdr->completion_ops->completion(hdr);
133}
134
135static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
136{
137 ctx->error = error;
138 smp_wmb();
139 set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
140}
141
142static struct nfs_page *nfs_page_find_request_locked(struct page *page)
143{
144 struct nfs_page *req = NULL;
145
146 if (PagePrivate(page)) {
147 req = (struct nfs_page *)page_private(page);
148 if (req != NULL)
149 kref_get(&req->wb_kref);
150 }
151 return req;
152}
153
154static struct nfs_page *nfs_page_find_request(struct page *page)
155{
156 struct inode *inode = page->mapping->host;
157 struct nfs_page *req = NULL;
158
159 spin_lock(&inode->i_lock);
160 req = nfs_page_find_request_locked(page);
161 spin_unlock(&inode->i_lock);
162 return req;
163}
164
165/* Adjust the file length if we're writing beyond the end */
166static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
167{
168 struct inode *inode = page->mapping->host;
169 loff_t end, i_size;
170 pgoff_t end_index;
171
172 spin_lock(&inode->i_lock);
173 i_size = i_size_read(inode);
174 end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
175 if (i_size > 0 && page->index < end_index)
176 goto out;
177 end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
178 if (i_size >= end)
179 goto out;
180 i_size_write(inode, end);
181 nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
182out:
183 spin_unlock(&inode->i_lock);
184}
185
186/* A writeback failed: mark the page as bad, and invalidate the page cache */
187static void nfs_set_pageerror(struct page *page)
188{
189 SetPageError(page);
190 nfs_zap_mapping(page->mapping->host, page->mapping);
191}
192
193/* We can set the PG_uptodate flag if we see that a write request
194 * covers the full page.
195 */
196static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
197{
198 if (PageUptodate(page))
199 return;
200 if (base != 0)
201 return;
202 if (count != nfs_page_length(page))
203 return;
204 SetPageUptodate(page);
205}
206
207static int wb_priority(struct writeback_control *wbc)
208{
209 if (wbc->for_reclaim)
210 return FLUSH_HIGHPRI | FLUSH_STABLE;
211 if (wbc->for_kupdate || wbc->for_background)
212 return FLUSH_LOWPRI | FLUSH_COND_STABLE;
213 return FLUSH_COND_STABLE;
214}
215
216/*
217 * NFS congestion control
218 */
219
220int nfs_congestion_kb;
221
222#define NFS_CONGESTION_ON_THRESH (nfs_congestion_kb >> (PAGE_SHIFT-10))
223#define NFS_CONGESTION_OFF_THRESH \
224 (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
225
226static int nfs_set_page_writeback(struct page *page)
227{
228 int ret = test_set_page_writeback(page);
229
230 if (!ret) {
231 struct inode *inode = page->mapping->host;
232 struct nfs_server *nfss = NFS_SERVER(inode);
233
234 if (atomic_long_inc_return(&nfss->writeback) >
235 NFS_CONGESTION_ON_THRESH) {
236 set_bdi_congested(&nfss->backing_dev_info,
237 BLK_RW_ASYNC);
238 }
239 }
240 return ret;
241}
242
243static void nfs_end_page_writeback(struct page *page)
244{
245 struct inode *inode = page->mapping->host;
246 struct nfs_server *nfss = NFS_SERVER(inode);
247
248 end_page_writeback(page);
249 if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
250 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
251}
252
253static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblock)
254{
255 struct inode *inode = page->mapping->host;
256 struct nfs_page *req;
257 int ret;
258
259 spin_lock(&inode->i_lock);
260 for (;;) {
261 req = nfs_page_find_request_locked(page);
262 if (req == NULL)
263 break;
264 if (nfs_lock_request(req))
265 break;
266 /* Note: If we hold the page lock, as is the case in nfs_writepage,
267 * then the call to nfs_lock_request() will always
268 * succeed provided that someone hasn't already marked the
269 * request as dirty (in which case we don't care).
270 */
271 spin_unlock(&inode->i_lock);
272 if (!nonblock)
273 ret = nfs_wait_on_request(req);
274 else
275 ret = -EAGAIN;
276 nfs_release_request(req);
277 if (ret != 0)
278 return ERR_PTR(ret);
279 spin_lock(&inode->i_lock);
280 }
281 spin_unlock(&inode->i_lock);
282 return req;
283}
284
285/*
286 * Find an associated nfs write request, and prepare to flush it out
287 * May return an error if the user signalled nfs_wait_on_request().
288 */
289static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
290 struct page *page, bool nonblock)
291{
292 struct nfs_page *req;
293 int ret = 0;
294
295 req = nfs_find_and_lock_request(page, nonblock);
296 if (!req)
297 goto out;
298 ret = PTR_ERR(req);
299 if (IS_ERR(req))
300 goto out;
301
302 ret = nfs_set_page_writeback(page);
303 BUG_ON(ret != 0);
304 BUG_ON(test_bit(PG_CLEAN, &req->wb_flags));
305
306 if (!nfs_pageio_add_request(pgio, req)) {
307 nfs_redirty_request(req);
308 ret = pgio->pg_error;
309 }
310out:
311 return ret;
312}
313
314static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
315{
316 struct inode *inode = page->mapping->host;
317 int ret;
318
319 nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
320 nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
321
322 nfs_pageio_cond_complete(pgio, page->index);
323 ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
324 if (ret == -EAGAIN) {
325 redirty_page_for_writepage(wbc, page);
326 ret = 0;
327 }
328 return ret;
329}
330
331/*
332 * Write an mmapped page to the server.
333 */
334static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
335{
336 struct nfs_pageio_descriptor pgio;
337 int err;
338
339 nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc),
340 &nfs_async_write_completion_ops);
341 err = nfs_do_writepage(page, wbc, &pgio);
342 nfs_pageio_complete(&pgio);
343 if (err < 0)
344 return err;
345 if (pgio.pg_error < 0)
346 return pgio.pg_error;
347 return 0;
348}
349
350int nfs_writepage(struct page *page, struct writeback_control *wbc)
351{
352 int ret;
353
354 ret = nfs_writepage_locked(page, wbc);
355 unlock_page(page);
356 return ret;
357}
358
359static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
360{
361 int ret;
362
363 ret = nfs_do_writepage(page, wbc, data);
364 unlock_page(page);
365 return ret;
366}
367
368int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
369{
370 struct inode *inode = mapping->host;
371 unsigned long *bitlock = &NFS_I(inode)->flags;
372 struct nfs_pageio_descriptor pgio;
373 int err;
374
375 /* Stop dirtying of new pages while we sync */
376 err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
377 nfs_wait_bit_killable, TASK_KILLABLE);
378 if (err)
379 goto out_err;
380
381 nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
382
383 nfs_pageio_init_write(&pgio, inode, wb_priority(wbc),
384 &nfs_async_write_completion_ops);
385 err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
386 nfs_pageio_complete(&pgio);
387
388 clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
389 smp_mb__after_clear_bit();
390 wake_up_bit(bitlock, NFS_INO_FLUSHING);
391
392 if (err < 0)
393 goto out_err;
394 err = pgio.pg_error;
395 if (err < 0)
396 goto out_err;
397 return 0;
398out_err:
399 return err;
400}
401
402/*
403 * Insert a write request into an inode
404 */
405static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
406{
407 struct nfs_inode *nfsi = NFS_I(inode);
408
409 /* Lock the request! */
410 nfs_lock_request(req);
411
412 spin_lock(&inode->i_lock);
413 if (!nfsi->npages && nfs_have_delegation(inode, FMODE_WRITE))
414 inode->i_version++;
415 set_bit(PG_MAPPED, &req->wb_flags);
416 SetPagePrivate(req->wb_page);
417 set_page_private(req->wb_page, (unsigned long)req);
418 nfsi->npages++;
419 kref_get(&req->wb_kref);
420 spin_unlock(&inode->i_lock);
421}
422
423/*
424 * Remove a write request from an inode
425 */
426static void nfs_inode_remove_request(struct nfs_page *req)
427{
428 struct inode *inode = req->wb_context->dentry->d_inode;
429 struct nfs_inode *nfsi = NFS_I(inode);
430
431 BUG_ON (!NFS_WBACK_BUSY(req));
432
433 spin_lock(&inode->i_lock);
434 set_page_private(req->wb_page, 0);
435 ClearPagePrivate(req->wb_page);
436 clear_bit(PG_MAPPED, &req->wb_flags);
437 nfsi->npages--;
438 spin_unlock(&inode->i_lock);
439 nfs_release_request(req);
440}
441
442static void
443nfs_mark_request_dirty(struct nfs_page *req)
444{
445 __set_page_dirty_nobuffers(req->wb_page);
446}
447
448#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
449/**
450 * nfs_request_add_commit_list - add request to a commit list
451 * @req: pointer to a struct nfs_page
452 * @dst: commit list head
453 * @cinfo: holds list lock and accounting info
454 *
455 * This sets the PG_CLEAN bit, updates the cinfo count of
456 * number of outstanding requests requiring a commit as well as
457 * the MM page stats.
458 *
459 * The caller must _not_ hold the cinfo->lock, but must be
460 * holding the nfs_page lock.
461 */
462void
463nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst,
464 struct nfs_commit_info *cinfo)
465{
466 set_bit(PG_CLEAN, &(req)->wb_flags);
467 spin_lock(cinfo->lock);
468 nfs_list_add_request(req, dst);
469 cinfo->mds->ncommit++;
470 spin_unlock(cinfo->lock);
471 if (!cinfo->dreq) {
472 inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
473 inc_bdi_stat(req->wb_page->mapping->backing_dev_info,
474 BDI_RECLAIMABLE);
475 __mark_inode_dirty(req->wb_context->dentry->d_inode,
476 I_DIRTY_DATASYNC);
477 }
478}
479EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
480
481/**
482 * nfs_request_remove_commit_list - Remove request from a commit list
483 * @req: pointer to a nfs_page
484 * @cinfo: holds list lock and accounting info
485 *
486 * This clears the PG_CLEAN bit, and updates the cinfo's count of
487 * number of outstanding requests requiring a commit
488 * It does not update the MM page stats.
489 *
490 * The caller _must_ hold the cinfo->lock and the nfs_page lock.
491 */
492void
493nfs_request_remove_commit_list(struct nfs_page *req,
494 struct nfs_commit_info *cinfo)
495{
496 if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
497 return;
498 nfs_list_remove_request(req);
499 cinfo->mds->ncommit--;
500}
501EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
502
503static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
504 struct inode *inode)
505{
506 cinfo->lock = &inode->i_lock;
507 cinfo->mds = &NFS_I(inode)->commit_info;
508 cinfo->ds = pnfs_get_ds_info(inode);
509 cinfo->dreq = NULL;
510 cinfo->completion_ops = &nfs_commit_completion_ops;
511}
512
513void nfs_init_cinfo(struct nfs_commit_info *cinfo,
514 struct inode *inode,
515 struct nfs_direct_req *dreq)
516{
517 if (dreq)
518 nfs_init_cinfo_from_dreq(cinfo, dreq);
519 else
520 nfs_init_cinfo_from_inode(cinfo, inode);
521}
522EXPORT_SYMBOL_GPL(nfs_init_cinfo);
523
524/*
525 * Add a request to the inode's commit list.
526 */
527void
528nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
529 struct nfs_commit_info *cinfo)
530{
531 if (pnfs_mark_request_commit(req, lseg, cinfo))
532 return;
533 nfs_request_add_commit_list(req, &cinfo->mds->list, cinfo);
534}
535
536static void
537nfs_clear_page_commit(struct page *page)
538{
539 dec_zone_page_state(page, NR_UNSTABLE_NFS);
540 dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
541}
542
543static void
544nfs_clear_request_commit(struct nfs_page *req)
545{
546 if (test_bit(PG_CLEAN, &req->wb_flags)) {
547 struct inode *inode = req->wb_context->dentry->d_inode;
548 struct nfs_commit_info cinfo;
549
550 nfs_init_cinfo_from_inode(&cinfo, inode);
551 if (!pnfs_clear_request_commit(req, &cinfo)) {
552 spin_lock(cinfo.lock);
553 nfs_request_remove_commit_list(req, &cinfo);
554 spin_unlock(cinfo.lock);
555 }
556 nfs_clear_page_commit(req->wb_page);
557 }
558}
559
560static inline
561int nfs_write_need_commit(struct nfs_write_data *data)
562{
563 if (data->verf.committed == NFS_DATA_SYNC)
564 return data->header->lseg == NULL;
565 return data->verf.committed != NFS_FILE_SYNC;
566}
567
568#else
569static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
570 struct inode *inode)
571{
572}
573
574void nfs_init_cinfo(struct nfs_commit_info *cinfo,
575 struct inode *inode,
576 struct nfs_direct_req *dreq)
577{
578}
579
580void
581nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
582 struct nfs_commit_info *cinfo)
583{
584}
585
586static void
587nfs_clear_request_commit(struct nfs_page *req)
588{
589}
590
591static inline
592int nfs_write_need_commit(struct nfs_write_data *data)
593{
594 return 0;
595}
596
597#endif
598
599static void nfs_write_completion(struct nfs_pgio_header *hdr)
600{
601 struct nfs_commit_info cinfo;
602 unsigned long bytes = 0;
603
604 if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
605 goto out;
606 nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
607 while (!list_empty(&hdr->pages)) {
608 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
609
610 bytes += req->wb_bytes;
611 nfs_list_remove_request(req);
612 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
613 (hdr->good_bytes < bytes)) {
614 nfs_set_pageerror(req->wb_page);
615 nfs_context_set_write_error(req->wb_context, hdr->error);
616 goto remove_req;
617 }
618 if (test_bit(NFS_IOHDR_NEED_RESCHED, &hdr->flags)) {
619 nfs_mark_request_dirty(req);
620 goto next;
621 }
622 if (test_bit(NFS_IOHDR_NEED_COMMIT, &hdr->flags)) {
623 memcpy(&req->wb_verf, hdr->verf, sizeof(req->wb_verf));
624 nfs_mark_request_commit(req, hdr->lseg, &cinfo);
625 goto next;
626 }
627remove_req:
628 nfs_inode_remove_request(req);
629next:
630 nfs_unlock_request(req);
631 nfs_end_page_writeback(req->wb_page);
632 nfs_release_request(req);
633 }
634out:
635 hdr->release(hdr);
636}
637
638#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
639static unsigned long
640nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
641{
642 return cinfo->mds->ncommit;
643}
644
645/* cinfo->lock held by caller */
646int
647nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
648 struct nfs_commit_info *cinfo, int max)
649{
650 struct nfs_page *req, *tmp;
651 int ret = 0;
652
653 list_for_each_entry_safe(req, tmp, src, wb_list) {
654 if (!nfs_lock_request(req))
655 continue;
656 kref_get(&req->wb_kref);
657 if (cond_resched_lock(cinfo->lock))
658 list_safe_reset_next(req, tmp, wb_list);
659 nfs_request_remove_commit_list(req, cinfo);
660 nfs_list_add_request(req, dst);
661 ret++;
662 if ((ret == max) && !cinfo->dreq)
663 break;
664 }
665 return ret;
666}
667
668/*
669 * nfs_scan_commit - Scan an inode for commit requests
670 * @inode: NFS inode to scan
671 * @dst: mds destination list
672 * @cinfo: mds and ds lists of reqs ready to commit
673 *
674 * Moves requests from the inode's 'commit' request list.
675 * The requests are *not* checked to ensure that they form a contiguous set.
676 */
677int
678nfs_scan_commit(struct inode *inode, struct list_head *dst,
679 struct nfs_commit_info *cinfo)
680{
681 int ret = 0;
682
683 spin_lock(cinfo->lock);
684 if (cinfo->mds->ncommit > 0) {
685 const int max = INT_MAX;
686
687 ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
688 cinfo, max);
689 ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
690 }
691 spin_unlock(cinfo->lock);
692 return ret;
693}
694
695#else
696static unsigned long nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
697{
698 return 0;
699}
700
701int nfs_scan_commit(struct inode *inode, struct list_head *dst,
702 struct nfs_commit_info *cinfo)
703{
704 return 0;
705}
706#endif
707
708/*
709 * Search for an existing write request, and attempt to update
710 * it to reflect a new dirty region on a given page.
711 *
712 * If the attempt fails, then the existing request is flushed out
713 * to disk.
714 */
715static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
716 struct page *page,
717 unsigned int offset,
718 unsigned int bytes)
719{
720 struct nfs_page *req;
721 unsigned int rqend;
722 unsigned int end;
723 int error;
724
725 if (!PagePrivate(page))
726 return NULL;
727
728 end = offset + bytes;
729 spin_lock(&inode->i_lock);
730
731 for (;;) {
732 req = nfs_page_find_request_locked(page);
733 if (req == NULL)
734 goto out_unlock;
735
736 rqend = req->wb_offset + req->wb_bytes;
737 /*
738 * Tell the caller to flush out the request if
739 * the offsets are non-contiguous.
740 * Note: nfs_flush_incompatible() will already
741 * have flushed out requests having wrong owners.
742 */
743 if (offset > rqend
744 || end < req->wb_offset)
745 goto out_flushme;
746
747 if (nfs_lock_request(req))
748 break;
749
750 /* The request is locked, so wait and then retry */
751 spin_unlock(&inode->i_lock);
752 error = nfs_wait_on_request(req);
753 nfs_release_request(req);
754 if (error != 0)
755 goto out_err;
756 spin_lock(&inode->i_lock);
757 }
758
759 /* Okay, the request matches. Update the region */
760 if (offset < req->wb_offset) {
761 req->wb_offset = offset;
762 req->wb_pgbase = offset;
763 }
764 if (end > rqend)
765 req->wb_bytes = end - req->wb_offset;
766 else
767 req->wb_bytes = rqend - req->wb_offset;
768out_unlock:
769 spin_unlock(&inode->i_lock);
770 if (req)
771 nfs_clear_request_commit(req);
772 return req;
773out_flushme:
774 spin_unlock(&inode->i_lock);
775 nfs_release_request(req);
776 error = nfs_wb_page(inode, page);
777out_err:
778 return ERR_PTR(error);
779}
780
781/*
782 * Try to update an existing write request, or create one if there is none.
783 *
784 * Note: Should always be called with the Page Lock held to prevent races
785 * if we have to add a new request. Also assumes that the caller has
786 * already called nfs_flush_incompatible() if necessary.
787 */
788static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
789 struct page *page, unsigned int offset, unsigned int bytes)
790{
791 struct inode *inode = page->mapping->host;
792 struct nfs_page *req;
793
794 req = nfs_try_to_update_request(inode, page, offset, bytes);
795 if (req != NULL)
796 goto out;
797 req = nfs_create_request(ctx, inode, page, offset, bytes);
798 if (IS_ERR(req))
799 goto out;
800 nfs_inode_add_request(inode, req);
801out:
802 return req;
803}
804
805static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
806 unsigned int offset, unsigned int count)
807{
808 struct nfs_page *req;
809
810 req = nfs_setup_write_request(ctx, page, offset, count);
811 if (IS_ERR(req))
812 return PTR_ERR(req);
813 /* Update file length */
814 nfs_grow_file(page, offset, count);
815 nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
816 nfs_mark_request_dirty(req);
817 nfs_unlock_and_release_request(req);
818 return 0;
819}
820
821int nfs_flush_incompatible(struct file *file, struct page *page)
822{
823 struct nfs_open_context *ctx = nfs_file_open_context(file);
824 struct nfs_page *req;
825 int do_flush, status;
826 /*
827 * Look for a request corresponding to this page. If there
828 * is one, and it belongs to another file, we flush it out
829 * before we try to copy anything into the page. Do this
830 * due to the lack of an ACCESS-type call in NFSv2.
831 * Also do the same if we find a request from an existing
832 * dropped page.
833 */
834 do {
835 req = nfs_page_find_request(page);
836 if (req == NULL)
837 return 0;
838 do_flush = req->wb_page != page || req->wb_context != ctx ||
839 req->wb_lock_context->lockowner != current->files ||
840 req->wb_lock_context->pid != current->tgid;
841 nfs_release_request(req);
842 if (!do_flush)
843 return 0;
844 status = nfs_wb_page(page->mapping->host, page);
845 } while (status == 0);
846 return status;
847}
848
849/*
850 * If the page cache is marked as unsafe or invalid, then we can't rely on
851 * the PageUptodate() flag. In this case, we will need to turn off
852 * write optimisations that depend on the page contents being correct.
853 */
854static bool nfs_write_pageuptodate(struct page *page, struct inode *inode)
855{
856 if (nfs_have_delegated_attributes(inode))
857 goto out;
858 if (NFS_I(inode)->cache_validity & NFS_INO_REVAL_PAGECACHE)
859 return false;
860out:
861 return PageUptodate(page) != 0;
862}
863
864/*
865 * Update and possibly write a cached page of an NFS file.
866 *
867 * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
868 * things with a page scheduled for an RPC call (e.g. invalidate it).
869 */
870int nfs_updatepage(struct file *file, struct page *page,
871 unsigned int offset, unsigned int count)
872{
873 struct nfs_open_context *ctx = nfs_file_open_context(file);
874 struct inode *inode = page->mapping->host;
875 int status = 0;
876
877 nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
878
879 dprintk("NFS: nfs_updatepage(%s/%s %d@%lld)\n",
880 file->f_path.dentry->d_parent->d_name.name,
881 file->f_path.dentry->d_name.name, count,
882 (long long)(page_offset(page) + offset));
883
884 /* If we're not using byte range locks, and we know the page
885 * is up to date, it may be more efficient to extend the write
886 * to cover the entire page in order to avoid fragmentation
887 * inefficiencies.
888 */
889 if (nfs_write_pageuptodate(page, inode) &&
890 inode->i_flock == NULL &&
891 !(file->f_flags & O_DSYNC)) {
892 count = max(count + offset, nfs_page_length(page));
893 offset = 0;
894 }
895
896 status = nfs_writepage_setup(ctx, page, offset, count);
897 if (status < 0)
898 nfs_set_pageerror(page);
899 else
900 __set_page_dirty_nobuffers(page);
901
902 dprintk("NFS: nfs_updatepage returns %d (isize %lld)\n",
903 status, (long long)i_size_read(inode));
904 return status;
905}
906
907static int flush_task_priority(int how)
908{
909 switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
910 case FLUSH_HIGHPRI:
911 return RPC_PRIORITY_HIGH;
912 case FLUSH_LOWPRI:
913 return RPC_PRIORITY_LOW;
914 }
915 return RPC_PRIORITY_NORMAL;
916}
917
918int nfs_initiate_write(struct rpc_clnt *clnt,
919 struct nfs_write_data *data,
920 const struct rpc_call_ops *call_ops,
921 int how, int flags)
922{
923 struct inode *inode = data->header->inode;
924 int priority = flush_task_priority(how);
925 struct rpc_task *task;
926 struct rpc_message msg = {
927 .rpc_argp = &data->args,
928 .rpc_resp = &data->res,
929 .rpc_cred = data->header->cred,
930 };
931 struct rpc_task_setup task_setup_data = {
932 .rpc_client = clnt,
933 .task = &data->task,
934 .rpc_message = &msg,
935 .callback_ops = call_ops,
936 .callback_data = data,
937 .workqueue = nfsiod_workqueue,
938 .flags = RPC_TASK_ASYNC | flags,
939 .priority = priority,
940 };
941 int ret = 0;
942
943 /* Set up the initial task struct. */
944 NFS_PROTO(inode)->write_setup(data, &msg);
945
946 dprintk("NFS: %5u initiated write call "
947 "(req %s/%lld, %u bytes @ offset %llu)\n",
948 data->task.tk_pid,
949 inode->i_sb->s_id,
950 (long long)NFS_FILEID(inode),
951 data->args.count,
952 (unsigned long long)data->args.offset);
953
954 task = rpc_run_task(&task_setup_data);
955 if (IS_ERR(task)) {
956 ret = PTR_ERR(task);
957 goto out;
958 }
959 if (how & FLUSH_SYNC) {
960 ret = rpc_wait_for_completion_task(task);
961 if (ret == 0)
962 ret = task->tk_status;
963 }
964 rpc_put_task(task);
965out:
966 return ret;
967}
968EXPORT_SYMBOL_GPL(nfs_initiate_write);
969
970/*
971 * Set up the argument/result storage required for the RPC call.
972 */
973static void nfs_write_rpcsetup(struct nfs_write_data *data,
974 unsigned int count, unsigned int offset,
975 int how, struct nfs_commit_info *cinfo)
976{
977 struct nfs_page *req = data->header->req;
978
979 /* Set up the RPC argument and reply structs
980 * NB: take care not to mess about with data->commit et al. */
981
982 data->args.fh = NFS_FH(data->header->inode);
983 data->args.offset = req_offset(req) + offset;
984 /* pnfs_set_layoutcommit needs this */
985 data->mds_offset = data->args.offset;
986 data->args.pgbase = req->wb_pgbase + offset;
987 data->args.pages = data->pages.pagevec;
988 data->args.count = count;
989 data->args.context = get_nfs_open_context(req->wb_context);
990 data->args.lock_context = req->wb_lock_context;
991 data->args.stable = NFS_UNSTABLE;
992 switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
993 case 0:
994 break;
995 case FLUSH_COND_STABLE:
996 if (nfs_reqs_to_commit(cinfo))
997 break;
998 default:
999 data->args.stable = NFS_FILE_SYNC;
1000 }
1001
1002 data->res.fattr = &data->fattr;
1003 data->res.count = count;
1004 data->res.verf = &data->verf;
1005 nfs_fattr_init(&data->fattr);
1006}
1007
1008static int nfs_do_write(struct nfs_write_data *data,
1009 const struct rpc_call_ops *call_ops,
1010 int how)
1011{
1012 struct inode *inode = data->header->inode;
1013
1014 return nfs_initiate_write(NFS_CLIENT(inode), data, call_ops, how, 0);
1015}
1016
1017static int nfs_do_multiple_writes(struct list_head *head,
1018 const struct rpc_call_ops *call_ops,
1019 int how)
1020{
1021 struct nfs_write_data *data;
1022 int ret = 0;
1023
1024 while (!list_empty(head)) {
1025 int ret2;
1026
1027 data = list_first_entry(head, struct nfs_write_data, list);
1028 list_del_init(&data->list);
1029
1030 ret2 = nfs_do_write(data, call_ops, how);
1031 if (ret == 0)
1032 ret = ret2;
1033 }
1034 return ret;
1035}
1036
1037/* If a nfs_flush_* function fails, it should remove reqs from @head and
1038 * call this on each, which will prepare them to be retried on next
1039 * writeback using standard nfs.
1040 */
1041static void nfs_redirty_request(struct nfs_page *req)
1042{
1043 nfs_mark_request_dirty(req);
1044 nfs_unlock_request(req);
1045 nfs_end_page_writeback(req->wb_page);
1046 nfs_release_request(req);
1047}
1048
1049static void nfs_async_write_error(struct list_head *head)
1050{
1051 struct nfs_page *req;
1052
1053 while (!list_empty(head)) {
1054 req = nfs_list_entry(head->next);
1055 nfs_list_remove_request(req);
1056 nfs_redirty_request(req);
1057 }
1058}
1059
1060static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
1061 .error_cleanup = nfs_async_write_error,
1062 .completion = nfs_write_completion,
1063};
1064
1065static void nfs_flush_error(struct nfs_pageio_descriptor *desc,
1066 struct nfs_pgio_header *hdr)
1067{
1068 set_bit(NFS_IOHDR_REDO, &hdr->flags);
1069 while (!list_empty(&hdr->rpc_list)) {
1070 struct nfs_write_data *data = list_first_entry(&hdr->rpc_list,
1071 struct nfs_write_data, list);
1072 list_del(&data->list);
1073 nfs_writedata_release(data);
1074 }
1075 desc->pg_completion_ops->error_cleanup(&desc->pg_list);
1076}
1077
1078/*
1079 * Generate multiple small requests to write out a single
1080 * contiguous dirty area on one page.
1081 */
1082static int nfs_flush_multi(struct nfs_pageio_descriptor *desc,
1083 struct nfs_pgio_header *hdr)
1084{
1085 struct nfs_page *req = hdr->req;
1086 struct page *page = req->wb_page;
1087 struct nfs_write_data *data;
1088 size_t wsize = desc->pg_bsize, nbytes;
1089 unsigned int offset;
1090 int requests = 0;
1091 struct nfs_commit_info cinfo;
1092
1093 nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
1094
1095 if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1096 (desc->pg_moreio || nfs_reqs_to_commit(&cinfo) ||
1097 desc->pg_count > wsize))
1098 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1099
1100
1101 offset = 0;
1102 nbytes = desc->pg_count;
1103 do {
1104 size_t len = min(nbytes, wsize);
1105
1106 data = nfs_writedata_alloc(hdr, 1);
1107 if (!data) {
1108 nfs_flush_error(desc, hdr);
1109 return -ENOMEM;
1110 }
1111 data->pages.pagevec[0] = page;
1112 nfs_write_rpcsetup(data, len, offset, desc->pg_ioflags, &cinfo);
1113 list_add(&data->list, &hdr->rpc_list);
1114 requests++;
1115 nbytes -= len;
1116 offset += len;
1117 } while (nbytes != 0);
1118 nfs_list_remove_request(req);
1119 nfs_list_add_request(req, &hdr->pages);
1120 desc->pg_rpc_callops = &nfs_write_common_ops;
1121 return 0;
1122}
1123
1124/*
1125 * Create an RPC task for the given write request and kick it.
1126 * The page must have been locked by the caller.
1127 *
1128 * It may happen that the page we're passed is not marked dirty.
1129 * This is the case if nfs_updatepage detects a conflicting request
1130 * that has been written but not committed.
1131 */
1132static int nfs_flush_one(struct nfs_pageio_descriptor *desc,
1133 struct nfs_pgio_header *hdr)
1134{
1135 struct nfs_page *req;
1136 struct page **pages;
1137 struct nfs_write_data *data;
1138 struct list_head *head = &desc->pg_list;
1139 struct nfs_commit_info cinfo;
1140
1141 data = nfs_writedata_alloc(hdr, nfs_page_array_len(desc->pg_base,
1142 desc->pg_count));
1143 if (!data) {
1144 nfs_flush_error(desc, hdr);
1145 return -ENOMEM;
1146 }
1147
1148 nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
1149 pages = data->pages.pagevec;
1150 while (!list_empty(head)) {
1151 req = nfs_list_entry(head->next);
1152 nfs_list_remove_request(req);
1153 nfs_list_add_request(req, &hdr->pages);
1154 *pages++ = req->wb_page;
1155 }
1156
1157 if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1158 (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
1159 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1160
1161 /* Set up the argument struct */
1162 nfs_write_rpcsetup(data, desc->pg_count, 0, desc->pg_ioflags, &cinfo);
1163 list_add(&data->list, &hdr->rpc_list);
1164 desc->pg_rpc_callops = &nfs_write_common_ops;
1165 return 0;
1166}
1167
1168int nfs_generic_flush(struct nfs_pageio_descriptor *desc,
1169 struct nfs_pgio_header *hdr)
1170{
1171 if (desc->pg_bsize < PAGE_CACHE_SIZE)
1172 return nfs_flush_multi(desc, hdr);
1173 return nfs_flush_one(desc, hdr);
1174}
1175
1176static int nfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
1177{
1178 struct nfs_write_header *whdr;
1179 struct nfs_pgio_header *hdr;
1180 int ret;
1181
1182 whdr = nfs_writehdr_alloc();
1183 if (!whdr) {
1184 desc->pg_completion_ops->error_cleanup(&desc->pg_list);
1185 return -ENOMEM;
1186 }
1187 hdr = &whdr->header;
1188 nfs_pgheader_init(desc, hdr, nfs_writehdr_free);
1189 atomic_inc(&hdr->refcnt);
1190 ret = nfs_generic_flush(desc, hdr);
1191 if (ret == 0)
1192 ret = nfs_do_multiple_writes(&hdr->rpc_list,
1193 desc->pg_rpc_callops,
1194 desc->pg_ioflags);
1195 if (atomic_dec_and_test(&hdr->refcnt))
1196 hdr->completion_ops->completion(hdr);
1197 return ret;
1198}
1199
1200static const struct nfs_pageio_ops nfs_pageio_write_ops = {
1201 .pg_test = nfs_generic_pg_test,
1202 .pg_doio = nfs_generic_pg_writepages,
1203};
1204
1205void nfs_pageio_init_write_mds(struct nfs_pageio_descriptor *pgio,
1206 struct inode *inode, int ioflags,
1207 const struct nfs_pgio_completion_ops *compl_ops)
1208{
1209 nfs_pageio_init(pgio, inode, &nfs_pageio_write_ops, compl_ops,
1210 NFS_SERVER(inode)->wsize, ioflags);
1211}
1212
1213void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1214{
1215 pgio->pg_ops = &nfs_pageio_write_ops;
1216 pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1217}
1218EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1219
1220void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1221 struct inode *inode, int ioflags,
1222 const struct nfs_pgio_completion_ops *compl_ops)
1223{
1224 if (!pnfs_pageio_init_write(pgio, inode, ioflags, compl_ops))
1225 nfs_pageio_init_write_mds(pgio, inode, ioflags, compl_ops);
1226}
1227
1228void nfs_write_prepare(struct rpc_task *task, void *calldata)
1229{
1230 struct nfs_write_data *data = calldata;
1231 NFS_PROTO(data->header->inode)->write_rpc_prepare(task, data);
1232}
1233
1234void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1235{
1236 struct nfs_commit_data *data = calldata;
1237
1238 NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1239}
1240
1241/*
1242 * Handle a write reply that flushes a whole page.
1243 *
1244 * FIXME: There is an inherent race with invalidate_inode_pages and
1245 * writebacks since the page->count is kept > 1 for as long
1246 * as the page has a write request pending.
1247 */
1248static void nfs_writeback_done_common(struct rpc_task *task, void *calldata)
1249{
1250 struct nfs_write_data *data = calldata;
1251
1252 nfs_writeback_done(task, data);
1253}
1254
1255static void nfs_writeback_release_common(void *calldata)
1256{
1257 struct nfs_write_data *data = calldata;
1258 struct nfs_pgio_header *hdr = data->header;
1259 int status = data->task.tk_status;
1260
1261 if ((status >= 0) && nfs_write_need_commit(data)) {
1262 spin_lock(&hdr->lock);
1263 if (test_bit(NFS_IOHDR_NEED_RESCHED, &hdr->flags))
1264 ; /* Do nothing */
1265 else if (!test_and_set_bit(NFS_IOHDR_NEED_COMMIT, &hdr->flags))
1266 memcpy(hdr->verf, &data->verf, sizeof(*hdr->verf));
1267 else if (memcmp(hdr->verf, &data->verf, sizeof(*hdr->verf)))
1268 set_bit(NFS_IOHDR_NEED_RESCHED, &hdr->flags);
1269 spin_unlock(&hdr->lock);
1270 }
1271 nfs_writedata_release(data);
1272}
1273
1274static const struct rpc_call_ops nfs_write_common_ops = {
1275 .rpc_call_prepare = nfs_write_prepare,
1276 .rpc_call_done = nfs_writeback_done_common,
1277 .rpc_release = nfs_writeback_release_common,
1278};
1279
1280
1281/*
1282 * This function is called when the WRITE call is complete.
1283 */
1284void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
1285{
1286 struct nfs_writeargs *argp = &data->args;
1287 struct nfs_writeres *resp = &data->res;
1288 struct inode *inode = data->header->inode;
1289 int status;
1290
1291 dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1292 task->tk_pid, task->tk_status);
1293
1294 /*
1295 * ->write_done will attempt to use post-op attributes to detect
1296 * conflicting writes by other clients. A strict interpretation
1297 * of close-to-open would allow us to continue caching even if
1298 * another writer had changed the file, but some applications
1299 * depend on tighter cache coherency when writing.
1300 */
1301 status = NFS_PROTO(inode)->write_done(task, data);
1302 if (status != 0)
1303 return;
1304 nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1305
1306#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1307 if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1308 /* We tried a write call, but the server did not
1309 * commit data to stable storage even though we
1310 * requested it.
1311 * Note: There is a known bug in Tru64 < 5.0 in which
1312 * the server reports NFS_DATA_SYNC, but performs
1313 * NFS_FILE_SYNC. We therefore implement this checking
1314 * as a dprintk() in order to avoid filling syslog.
1315 */
1316 static unsigned long complain;
1317
1318 /* Note this will print the MDS for a DS write */
1319 if (time_before(complain, jiffies)) {
1320 dprintk("NFS: faulty NFS server %s:"
1321 " (committed = %d) != (stable = %d)\n",
1322 NFS_SERVER(inode)->nfs_client->cl_hostname,
1323 resp->verf->committed, argp->stable);
1324 complain = jiffies + 300 * HZ;
1325 }
1326 }
1327#endif
1328 if (task->tk_status < 0)
1329 nfs_set_pgio_error(data->header, task->tk_status, argp->offset);
1330 else if (resp->count < argp->count) {
1331 static unsigned long complain;
1332
1333 /* This a short write! */
1334 nfs_inc_stats(inode, NFSIOS_SHORTWRITE);
1335
1336 /* Has the server at least made some progress? */
1337 if (resp->count == 0) {
1338 if (time_before(complain, jiffies)) {
1339 printk(KERN_WARNING
1340 "NFS: Server wrote zero bytes, expected %u.\n",
1341 argp->count);
1342 complain = jiffies + 300 * HZ;
1343 }
1344 nfs_set_pgio_error(data->header, -EIO, argp->offset);
1345 task->tk_status = -EIO;
1346 return;
1347 }
1348 /* Was this an NFSv2 write or an NFSv3 stable write? */
1349 if (resp->verf->committed != NFS_UNSTABLE) {
1350 /* Resend from where the server left off */
1351 data->mds_offset += resp->count;
1352 argp->offset += resp->count;
1353 argp->pgbase += resp->count;
1354 argp->count -= resp->count;
1355 } else {
1356 /* Resend as a stable write in order to avoid
1357 * headaches in the case of a server crash.
1358 */
1359 argp->stable = NFS_FILE_SYNC;
1360 }
1361 rpc_restart_call_prepare(task);
1362 }
1363}
1364
1365
1366#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1367static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait)
1368{
1369 int ret;
1370
1371 if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags))
1372 return 1;
1373 if (!may_wait)
1374 return 0;
1375 ret = out_of_line_wait_on_bit_lock(&nfsi->flags,
1376 NFS_INO_COMMIT,
1377 nfs_wait_bit_killable,
1378 TASK_KILLABLE);
1379 return (ret < 0) ? ret : 1;
1380}
1381
1382static void nfs_commit_clear_lock(struct nfs_inode *nfsi)
1383{
1384 clear_bit(NFS_INO_COMMIT, &nfsi->flags);
1385 smp_mb__after_clear_bit();
1386 wake_up_bit(&nfsi->flags, NFS_INO_COMMIT);
1387}
1388
1389void nfs_commitdata_release(struct nfs_commit_data *data)
1390{
1391 put_nfs_open_context(data->context);
1392 nfs_commit_free(data);
1393}
1394EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1395
1396int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
1397 const struct rpc_call_ops *call_ops,
1398 int how, int flags)
1399{
1400 struct rpc_task *task;
1401 int priority = flush_task_priority(how);
1402 struct rpc_message msg = {
1403 .rpc_argp = &data->args,
1404 .rpc_resp = &data->res,
1405 .rpc_cred = data->cred,
1406 };
1407 struct rpc_task_setup task_setup_data = {
1408 .task = &data->task,
1409 .rpc_client = clnt,
1410 .rpc_message = &msg,
1411 .callback_ops = call_ops,
1412 .callback_data = data,
1413 .workqueue = nfsiod_workqueue,
1414 .flags = RPC_TASK_ASYNC | flags,
1415 .priority = priority,
1416 };
1417 /* Set up the initial task struct. */
1418 NFS_PROTO(data->inode)->commit_setup(data, &msg);
1419
1420 dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1421
1422 task = rpc_run_task(&task_setup_data);
1423 if (IS_ERR(task))
1424 return PTR_ERR(task);
1425 if (how & FLUSH_SYNC)
1426 rpc_wait_for_completion_task(task);
1427 rpc_put_task(task);
1428 return 0;
1429}
1430EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1431
1432/*
1433 * Set up the argument/result storage required for the RPC call.
1434 */
1435void nfs_init_commit(struct nfs_commit_data *data,
1436 struct list_head *head,
1437 struct pnfs_layout_segment *lseg,
1438 struct nfs_commit_info *cinfo)
1439{
1440 struct nfs_page *first = nfs_list_entry(head->next);
1441 struct inode *inode = first->wb_context->dentry->d_inode;
1442
1443 /* Set up the RPC argument and reply structs
1444 * NB: take care not to mess about with data->commit et al. */
1445
1446 list_splice_init(head, &data->pages);
1447
1448 data->inode = inode;
1449 data->cred = first->wb_context->cred;
1450 data->lseg = lseg; /* reference transferred */
1451 data->mds_ops = &nfs_commit_ops;
1452 data->completion_ops = cinfo->completion_ops;
1453 data->dreq = cinfo->dreq;
1454
1455 data->args.fh = NFS_FH(data->inode);
1456 /* Note: we always request a commit of the entire inode */
1457 data->args.offset = 0;
1458 data->args.count = 0;
1459 data->context = get_nfs_open_context(first->wb_context);
1460 data->res.fattr = &data->fattr;
1461 data->res.verf = &data->verf;
1462 nfs_fattr_init(&data->fattr);
1463}
1464EXPORT_SYMBOL_GPL(nfs_init_commit);
1465
1466void nfs_retry_commit(struct list_head *page_list,
1467 struct pnfs_layout_segment *lseg,
1468 struct nfs_commit_info *cinfo)
1469{
1470 struct nfs_page *req;
1471
1472 while (!list_empty(page_list)) {
1473 req = nfs_list_entry(page_list->next);
1474 nfs_list_remove_request(req);
1475 nfs_mark_request_commit(req, lseg, cinfo);
1476 if (!cinfo->dreq) {
1477 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1478 dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
1479 BDI_RECLAIMABLE);
1480 }
1481 nfs_unlock_and_release_request(req);
1482 }
1483}
1484EXPORT_SYMBOL_GPL(nfs_retry_commit);
1485
1486/*
1487 * Commit dirty pages
1488 */
1489static int
1490nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1491 struct nfs_commit_info *cinfo)
1492{
1493 struct nfs_commit_data *data;
1494
1495 data = nfs_commitdata_alloc();
1496
1497 if (!data)
1498 goto out_bad;
1499
1500 /* Set up the argument struct */
1501 nfs_init_commit(data, head, NULL, cinfo);
1502 atomic_inc(&cinfo->mds->rpcs_out);
1503 return nfs_initiate_commit(NFS_CLIENT(inode), data, data->mds_ops,
1504 how, 0);
1505 out_bad:
1506 nfs_retry_commit(head, NULL, cinfo);
1507 cinfo->completion_ops->error_cleanup(NFS_I(inode));
1508 return -ENOMEM;
1509}
1510
1511/*
1512 * COMMIT call returned
1513 */
1514static void nfs_commit_done(struct rpc_task *task, void *calldata)
1515{
1516 struct nfs_commit_data *data = calldata;
1517
1518 dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1519 task->tk_pid, task->tk_status);
1520
1521 /* Call the NFS version-specific code */
1522 NFS_PROTO(data->inode)->commit_done(task, data);
1523}
1524
1525static void nfs_commit_release_pages(struct nfs_commit_data *data)
1526{
1527 struct nfs_page *req;
1528 int status = data->task.tk_status;
1529 struct nfs_commit_info cinfo;
1530
1531 while (!list_empty(&data->pages)) {
1532 req = nfs_list_entry(data->pages.next);
1533 nfs_list_remove_request(req);
1534 nfs_clear_page_commit(req->wb_page);
1535
1536 dprintk("NFS: commit (%s/%lld %d@%lld)",
1537 req->wb_context->dentry->d_sb->s_id,
1538 (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1539 req->wb_bytes,
1540 (long long)req_offset(req));
1541 if (status < 0) {
1542 nfs_context_set_write_error(req->wb_context, status);
1543 nfs_inode_remove_request(req);
1544 dprintk(", error = %d\n", status);
1545 goto next;
1546 }
1547
1548 /* Okay, COMMIT succeeded, apparently. Check the verifier
1549 * returned by the server against all stored verfs. */
1550 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
1551 /* We have a match */
1552 nfs_inode_remove_request(req);
1553 dprintk(" OK\n");
1554 goto next;
1555 }
1556 /* We have a mismatch. Write the page again */
1557 dprintk(" mismatch\n");
1558 nfs_mark_request_dirty(req);
1559 next:
1560 nfs_unlock_and_release_request(req);
1561 }
1562 nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1563 if (atomic_dec_and_test(&cinfo.mds->rpcs_out))
1564 nfs_commit_clear_lock(NFS_I(data->inode));
1565}
1566
1567static void nfs_commit_release(void *calldata)
1568{
1569 struct nfs_commit_data *data = calldata;
1570
1571 data->completion_ops->completion(data);
1572 nfs_commitdata_release(calldata);
1573}
1574
1575static const struct rpc_call_ops nfs_commit_ops = {
1576 .rpc_call_prepare = nfs_commit_prepare,
1577 .rpc_call_done = nfs_commit_done,
1578 .rpc_release = nfs_commit_release,
1579};
1580
1581static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1582 .completion = nfs_commit_release_pages,
1583 .error_cleanup = nfs_commit_clear_lock,
1584};
1585
1586int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1587 int how, struct nfs_commit_info *cinfo)
1588{
1589 int status;
1590
1591 status = pnfs_commit_list(inode, head, how, cinfo);
1592 if (status == PNFS_NOT_ATTEMPTED)
1593 status = nfs_commit_list(inode, head, how, cinfo);
1594 return status;
1595}
1596
1597int nfs_commit_inode(struct inode *inode, int how)
1598{
1599 LIST_HEAD(head);
1600 struct nfs_commit_info cinfo;
1601 int may_wait = how & FLUSH_SYNC;
1602 int res;
1603
1604 res = nfs_commit_set_lock(NFS_I(inode), may_wait);
1605 if (res <= 0)
1606 goto out_mark_dirty;
1607 nfs_init_cinfo_from_inode(&cinfo, inode);
1608 res = nfs_scan_commit(inode, &head, &cinfo);
1609 if (res) {
1610 int error;
1611
1612 error = nfs_generic_commit_list(inode, &head, how, &cinfo);
1613 if (error < 0)
1614 return error;
1615 if (!may_wait)
1616 goto out_mark_dirty;
1617 error = wait_on_bit(&NFS_I(inode)->flags,
1618 NFS_INO_COMMIT,
1619 nfs_wait_bit_killable,
1620 TASK_KILLABLE);
1621 if (error < 0)
1622 return error;
1623 } else
1624 nfs_commit_clear_lock(NFS_I(inode));
1625 return res;
1626 /* Note: If we exit without ensuring that the commit is complete,
1627 * we must mark the inode as dirty. Otherwise, future calls to
1628 * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
1629 * that the data is on the disk.
1630 */
1631out_mark_dirty:
1632 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1633 return res;
1634}
1635
1636static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1637{
1638 struct nfs_inode *nfsi = NFS_I(inode);
1639 int flags = FLUSH_SYNC;
1640 int ret = 0;
1641
1642 /* no commits means nothing needs to be done */
1643 if (!nfsi->commit_info.ncommit)
1644 return ret;
1645
1646 if (wbc->sync_mode == WB_SYNC_NONE) {
1647 /* Don't commit yet if this is a non-blocking flush and there
1648 * are a lot of outstanding writes for this mapping.
1649 */
1650 if (nfsi->commit_info.ncommit <= (nfsi->npages >> 1))
1651 goto out_mark_dirty;
1652
1653 /* don't wait for the COMMIT response */
1654 flags = 0;
1655 }
1656
1657 ret = nfs_commit_inode(inode, flags);
1658 if (ret >= 0) {
1659 if (wbc->sync_mode == WB_SYNC_NONE) {
1660 if (ret < wbc->nr_to_write)
1661 wbc->nr_to_write -= ret;
1662 else
1663 wbc->nr_to_write = 0;
1664 }
1665 return 0;
1666 }
1667out_mark_dirty:
1668 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1669 return ret;
1670}
1671#else
1672static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1673{
1674 return 0;
1675}
1676#endif
1677
1678int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1679{
1680 int ret;
1681
1682 ret = nfs_commit_unstable_pages(inode, wbc);
1683 if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
1684 int status;
1685 bool sync = true;
1686
1687 if (wbc->sync_mode == WB_SYNC_NONE)
1688 sync = false;
1689
1690 status = pnfs_layoutcommit_inode(inode, sync);
1691 if (status < 0)
1692 return status;
1693 }
1694 return ret;
1695}
1696
1697/*
1698 * flush the inode to disk.
1699 */
1700int nfs_wb_all(struct inode *inode)
1701{
1702 struct writeback_control wbc = {
1703 .sync_mode = WB_SYNC_ALL,
1704 .nr_to_write = LONG_MAX,
1705 .range_start = 0,
1706 .range_end = LLONG_MAX,
1707 };
1708
1709 return sync_inode(inode, &wbc);
1710}
1711
1712int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1713{
1714 struct nfs_page *req;
1715 int ret = 0;
1716
1717 BUG_ON(!PageLocked(page));
1718 for (;;) {
1719 wait_on_page_writeback(page);
1720 req = nfs_page_find_request(page);
1721 if (req == NULL)
1722 break;
1723 if (nfs_lock_request(req)) {
1724 nfs_clear_request_commit(req);
1725 nfs_inode_remove_request(req);
1726 /*
1727 * In case nfs_inode_remove_request has marked the
1728 * page as being dirty
1729 */
1730 cancel_dirty_page(page, PAGE_CACHE_SIZE);
1731 nfs_unlock_and_release_request(req);
1732 break;
1733 }
1734 ret = nfs_wait_on_request(req);
1735 nfs_release_request(req);
1736 if (ret < 0)
1737 break;
1738 }
1739 return ret;
1740}
1741
1742/*
1743 * Write back all requests on one page - we do this before reading it.
1744 */
1745int nfs_wb_page(struct inode *inode, struct page *page)
1746{
1747 loff_t range_start = page_offset(page);
1748 loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1749 struct writeback_control wbc = {
1750 .sync_mode = WB_SYNC_ALL,
1751 .nr_to_write = 0,
1752 .range_start = range_start,
1753 .range_end = range_end,
1754 };
1755 int ret;
1756
1757 for (;;) {
1758 wait_on_page_writeback(page);
1759 if (clear_page_dirty_for_io(page)) {
1760 ret = nfs_writepage_locked(page, &wbc);
1761 if (ret < 0)
1762 goto out_error;
1763 continue;
1764 }
1765 if (!PagePrivate(page))
1766 break;
1767 ret = nfs_commit_inode(inode, FLUSH_SYNC);
1768 if (ret < 0)
1769 goto out_error;
1770 }
1771 return 0;
1772out_error:
1773 return ret;
1774}
1775
1776#ifdef CONFIG_MIGRATION
1777int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
1778 struct page *page, enum migrate_mode mode)
1779{
1780 /*
1781 * If PagePrivate is set, then the page is currently associated with
1782 * an in-progress read or write request. Don't try to migrate it.
1783 *
1784 * FIXME: we could do this in principle, but we'll need a way to ensure
1785 * that we can safely release the inode reference while holding
1786 * the page lock.
1787 */
1788 if (PagePrivate(page))
1789 return -EBUSY;
1790
1791 nfs_fscache_release_page(page, GFP_KERNEL);
1792
1793 return migrate_page(mapping, newpage, page, mode);
1794}
1795#endif
1796
1797int __init nfs_init_writepagecache(void)
1798{
1799 nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1800 sizeof(struct nfs_write_header),
1801 0, SLAB_HWCACHE_ALIGN,
1802 NULL);
1803 if (nfs_wdata_cachep == NULL)
1804 return -ENOMEM;
1805
1806 nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1807 nfs_wdata_cachep);
1808 if (nfs_wdata_mempool == NULL)
1809 goto out_destroy_write_cache;
1810
1811 nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
1812 sizeof(struct nfs_commit_data),
1813 0, SLAB_HWCACHE_ALIGN,
1814 NULL);
1815 if (nfs_cdata_cachep == NULL)
1816 goto out_destroy_write_mempool;
1817
1818 nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1819 nfs_wdata_cachep);
1820 if (nfs_commit_mempool == NULL)
1821 goto out_destroy_commit_cache;
1822
1823 /*
1824 * NFS congestion size, scale with available memory.
1825 *
1826 * 64MB: 8192k
1827 * 128MB: 11585k
1828 * 256MB: 16384k
1829 * 512MB: 23170k
1830 * 1GB: 32768k
1831 * 2GB: 46340k
1832 * 4GB: 65536k
1833 * 8GB: 92681k
1834 * 16GB: 131072k
1835 *
1836 * This allows larger machines to have larger/more transfers.
1837 * Limit the default to 256M
1838 */
1839 nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1840 if (nfs_congestion_kb > 256*1024)
1841 nfs_congestion_kb = 256*1024;
1842
1843 return 0;
1844
1845out_destroy_commit_cache:
1846 kmem_cache_destroy(nfs_cdata_cachep);
1847out_destroy_write_mempool:
1848 mempool_destroy(nfs_wdata_mempool);
1849out_destroy_write_cache:
1850 kmem_cache_destroy(nfs_wdata_cachep);
1851 return -ENOMEM;
1852}
1853
1854void nfs_destroy_writepagecache(void)
1855{
1856 mempool_destroy(nfs_commit_mempool);
1857 kmem_cache_destroy(nfs_cdata_cachep);
1858 mempool_destroy(nfs_wdata_mempool);
1859 kmem_cache_destroy(nfs_wdata_cachep);
1860}
1861
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
24#include <asm/uaccess.h>
25
26#include "delegation.h"
27#include "internal.h"
28#include "iostat.h"
29#include "nfs4_fs.h"
30#include "fscache.h"
31#include "pnfs.h"
32
33#define NFSDBG_FACILITY NFSDBG_PAGECACHE
34
35#define MIN_POOL_WRITE (32)
36#define MIN_POOL_COMMIT (4)
37
38/*
39 * Local function declarations
40 */
41static void nfs_pageio_init_write(struct nfs_pageio_descriptor *desc,
42 struct inode *inode, int ioflags);
43static void nfs_redirty_request(struct nfs_page *req);
44static const struct rpc_call_ops nfs_write_partial_ops;
45static const struct rpc_call_ops nfs_write_full_ops;
46static const struct rpc_call_ops nfs_commit_ops;
47
48static struct kmem_cache *nfs_wdata_cachep;
49static mempool_t *nfs_wdata_mempool;
50static mempool_t *nfs_commit_mempool;
51
52struct nfs_write_data *nfs_commitdata_alloc(void)
53{
54 struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
55
56 if (p) {
57 memset(p, 0, sizeof(*p));
58 INIT_LIST_HEAD(&p->pages);
59 }
60 return p;
61}
62EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
63
64void nfs_commit_free(struct nfs_write_data *p)
65{
66 if (p && (p->pagevec != &p->page_array[0]))
67 kfree(p->pagevec);
68 mempool_free(p, nfs_commit_mempool);
69}
70EXPORT_SYMBOL_GPL(nfs_commit_free);
71
72struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
73{
74 struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
75
76 if (p) {
77 memset(p, 0, sizeof(*p));
78 INIT_LIST_HEAD(&p->pages);
79 p->npages = pagecount;
80 if (pagecount <= ARRAY_SIZE(p->page_array))
81 p->pagevec = p->page_array;
82 else {
83 p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
84 if (!p->pagevec) {
85 mempool_free(p, nfs_wdata_mempool);
86 p = NULL;
87 }
88 }
89 }
90 return p;
91}
92
93void nfs_writedata_free(struct nfs_write_data *p)
94{
95 if (p && (p->pagevec != &p->page_array[0]))
96 kfree(p->pagevec);
97 mempool_free(p, nfs_wdata_mempool);
98}
99
100void nfs_writedata_release(struct nfs_write_data *wdata)
101{
102 put_lseg(wdata->lseg);
103 put_nfs_open_context(wdata->args.context);
104 nfs_writedata_free(wdata);
105}
106
107static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
108{
109 ctx->error = error;
110 smp_wmb();
111 set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
112}
113
114static struct nfs_page *nfs_page_find_request_locked(struct page *page)
115{
116 struct nfs_page *req = NULL;
117
118 if (PagePrivate(page)) {
119 req = (struct nfs_page *)page_private(page);
120 if (req != NULL)
121 kref_get(&req->wb_kref);
122 }
123 return req;
124}
125
126static struct nfs_page *nfs_page_find_request(struct page *page)
127{
128 struct inode *inode = page->mapping->host;
129 struct nfs_page *req = NULL;
130
131 spin_lock(&inode->i_lock);
132 req = nfs_page_find_request_locked(page);
133 spin_unlock(&inode->i_lock);
134 return req;
135}
136
137/* Adjust the file length if we're writing beyond the end */
138static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
139{
140 struct inode *inode = page->mapping->host;
141 loff_t end, i_size;
142 pgoff_t end_index;
143
144 spin_lock(&inode->i_lock);
145 i_size = i_size_read(inode);
146 end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
147 if (i_size > 0 && page->index < end_index)
148 goto out;
149 end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
150 if (i_size >= end)
151 goto out;
152 i_size_write(inode, end);
153 nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
154out:
155 spin_unlock(&inode->i_lock);
156}
157
158/* A writeback failed: mark the page as bad, and invalidate the page cache */
159static void nfs_set_pageerror(struct page *page)
160{
161 SetPageError(page);
162 nfs_zap_mapping(page->mapping->host, page->mapping);
163}
164
165/* We can set the PG_uptodate flag if we see that a write request
166 * covers the full page.
167 */
168static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
169{
170 if (PageUptodate(page))
171 return;
172 if (base != 0)
173 return;
174 if (count != nfs_page_length(page))
175 return;
176 SetPageUptodate(page);
177}
178
179static int wb_priority(struct writeback_control *wbc)
180{
181 if (wbc->for_reclaim)
182 return FLUSH_HIGHPRI | FLUSH_STABLE;
183 if (wbc->for_kupdate || wbc->for_background)
184 return FLUSH_LOWPRI | FLUSH_COND_STABLE;
185 return FLUSH_COND_STABLE;
186}
187
188/*
189 * NFS congestion control
190 */
191
192int nfs_congestion_kb;
193
194#define NFS_CONGESTION_ON_THRESH (nfs_congestion_kb >> (PAGE_SHIFT-10))
195#define NFS_CONGESTION_OFF_THRESH \
196 (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
197
198static int nfs_set_page_writeback(struct page *page)
199{
200 int ret = test_set_page_writeback(page);
201
202 if (!ret) {
203 struct inode *inode = page->mapping->host;
204 struct nfs_server *nfss = NFS_SERVER(inode);
205
206 page_cache_get(page);
207 if (atomic_long_inc_return(&nfss->writeback) >
208 NFS_CONGESTION_ON_THRESH) {
209 set_bdi_congested(&nfss->backing_dev_info,
210 BLK_RW_ASYNC);
211 }
212 }
213 return ret;
214}
215
216static void nfs_end_page_writeback(struct page *page)
217{
218 struct inode *inode = page->mapping->host;
219 struct nfs_server *nfss = NFS_SERVER(inode);
220
221 end_page_writeback(page);
222 page_cache_release(page);
223 if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
224 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
225}
226
227static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblock)
228{
229 struct inode *inode = page->mapping->host;
230 struct nfs_page *req;
231 int ret;
232
233 spin_lock(&inode->i_lock);
234 for (;;) {
235 req = nfs_page_find_request_locked(page);
236 if (req == NULL)
237 break;
238 if (nfs_set_page_tag_locked(req))
239 break;
240 /* Note: If we hold the page lock, as is the case in nfs_writepage,
241 * then the call to nfs_set_page_tag_locked() will always
242 * succeed provided that someone hasn't already marked the
243 * request as dirty (in which case we don't care).
244 */
245 spin_unlock(&inode->i_lock);
246 if (!nonblock)
247 ret = nfs_wait_on_request(req);
248 else
249 ret = -EAGAIN;
250 nfs_release_request(req);
251 if (ret != 0)
252 return ERR_PTR(ret);
253 spin_lock(&inode->i_lock);
254 }
255 spin_unlock(&inode->i_lock);
256 return req;
257}
258
259/*
260 * Find an associated nfs write request, and prepare to flush it out
261 * May return an error if the user signalled nfs_wait_on_request().
262 */
263static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
264 struct page *page, bool nonblock)
265{
266 struct nfs_page *req;
267 int ret = 0;
268
269 req = nfs_find_and_lock_request(page, nonblock);
270 if (!req)
271 goto out;
272 ret = PTR_ERR(req);
273 if (IS_ERR(req))
274 goto out;
275
276 ret = nfs_set_page_writeback(page);
277 BUG_ON(ret != 0);
278 BUG_ON(test_bit(PG_CLEAN, &req->wb_flags));
279
280 if (!nfs_pageio_add_request(pgio, req)) {
281 nfs_redirty_request(req);
282 ret = pgio->pg_error;
283 }
284out:
285 return ret;
286}
287
288static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
289{
290 struct inode *inode = page->mapping->host;
291 int ret;
292
293 nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
294 nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
295
296 nfs_pageio_cond_complete(pgio, page->index);
297 ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
298 if (ret == -EAGAIN) {
299 redirty_page_for_writepage(wbc, page);
300 ret = 0;
301 }
302 return ret;
303}
304
305/*
306 * Write an mmapped page to the server.
307 */
308static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
309{
310 struct nfs_pageio_descriptor pgio;
311 int err;
312
313 nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc));
314 err = nfs_do_writepage(page, wbc, &pgio);
315 nfs_pageio_complete(&pgio);
316 if (err < 0)
317 return err;
318 if (pgio.pg_error < 0)
319 return pgio.pg_error;
320 return 0;
321}
322
323int nfs_writepage(struct page *page, struct writeback_control *wbc)
324{
325 int ret;
326
327 ret = nfs_writepage_locked(page, wbc);
328 unlock_page(page);
329 return ret;
330}
331
332static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
333{
334 int ret;
335
336 ret = nfs_do_writepage(page, wbc, data);
337 unlock_page(page);
338 return ret;
339}
340
341int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
342{
343 struct inode *inode = mapping->host;
344 unsigned long *bitlock = &NFS_I(inode)->flags;
345 struct nfs_pageio_descriptor pgio;
346 int err;
347
348 /* Stop dirtying of new pages while we sync */
349 err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
350 nfs_wait_bit_killable, TASK_KILLABLE);
351 if (err)
352 goto out_err;
353
354 nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
355
356 nfs_pageio_init_write(&pgio, inode, wb_priority(wbc));
357 err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
358 nfs_pageio_complete(&pgio);
359
360 clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
361 smp_mb__after_clear_bit();
362 wake_up_bit(bitlock, NFS_INO_FLUSHING);
363
364 if (err < 0)
365 goto out_err;
366 err = pgio.pg_error;
367 if (err < 0)
368 goto out_err;
369 return 0;
370out_err:
371 return err;
372}
373
374/*
375 * Insert a write request into an inode
376 */
377static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
378{
379 struct nfs_inode *nfsi = NFS_I(inode);
380 int error;
381
382 error = radix_tree_preload(GFP_NOFS);
383 if (error != 0)
384 goto out;
385
386 /* Lock the request! */
387 nfs_lock_request_dontget(req);
388
389 spin_lock(&inode->i_lock);
390 error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
391 BUG_ON(error);
392 if (!nfsi->npages && nfs_have_delegation(inode, FMODE_WRITE))
393 nfsi->change_attr++;
394 set_bit(PG_MAPPED, &req->wb_flags);
395 SetPagePrivate(req->wb_page);
396 set_page_private(req->wb_page, (unsigned long)req);
397 nfsi->npages++;
398 kref_get(&req->wb_kref);
399 radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index,
400 NFS_PAGE_TAG_LOCKED);
401 spin_unlock(&inode->i_lock);
402 radix_tree_preload_end();
403out:
404 return error;
405}
406
407/*
408 * Remove a write request from an inode
409 */
410static void nfs_inode_remove_request(struct nfs_page *req)
411{
412 struct inode *inode = req->wb_context->dentry->d_inode;
413 struct nfs_inode *nfsi = NFS_I(inode);
414
415 BUG_ON (!NFS_WBACK_BUSY(req));
416
417 spin_lock(&inode->i_lock);
418 set_page_private(req->wb_page, 0);
419 ClearPagePrivate(req->wb_page);
420 clear_bit(PG_MAPPED, &req->wb_flags);
421 radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
422 nfsi->npages--;
423 spin_unlock(&inode->i_lock);
424 nfs_release_request(req);
425}
426
427static void
428nfs_mark_request_dirty(struct nfs_page *req)
429{
430 __set_page_dirty_nobuffers(req->wb_page);
431 __mark_inode_dirty(req->wb_page->mapping->host, I_DIRTY_DATASYNC);
432}
433
434#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
435/*
436 * Add a request to the inode's commit list.
437 */
438static void
439nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
440{
441 struct inode *inode = req->wb_context->dentry->d_inode;
442 struct nfs_inode *nfsi = NFS_I(inode);
443
444 spin_lock(&inode->i_lock);
445 set_bit(PG_CLEAN, &(req)->wb_flags);
446 radix_tree_tag_set(&nfsi->nfs_page_tree,
447 req->wb_index,
448 NFS_PAGE_TAG_COMMIT);
449 nfsi->ncommit++;
450 spin_unlock(&inode->i_lock);
451 pnfs_mark_request_commit(req, lseg);
452 inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
453 inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
454 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
455}
456
457static int
458nfs_clear_request_commit(struct nfs_page *req)
459{
460 struct page *page = req->wb_page;
461
462 if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
463 dec_zone_page_state(page, NR_UNSTABLE_NFS);
464 dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
465 return 1;
466 }
467 return 0;
468}
469
470static inline
471int nfs_write_need_commit(struct nfs_write_data *data)
472{
473 if (data->verf.committed == NFS_DATA_SYNC)
474 return data->lseg == NULL;
475 else
476 return data->verf.committed != NFS_FILE_SYNC;
477}
478
479static inline
480int nfs_reschedule_unstable_write(struct nfs_page *req,
481 struct nfs_write_data *data)
482{
483 if (test_and_clear_bit(PG_NEED_COMMIT, &req->wb_flags)) {
484 nfs_mark_request_commit(req, data->lseg);
485 return 1;
486 }
487 if (test_and_clear_bit(PG_NEED_RESCHED, &req->wb_flags)) {
488 nfs_mark_request_dirty(req);
489 return 1;
490 }
491 return 0;
492}
493#else
494static inline void
495nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
496{
497}
498
499static inline int
500nfs_clear_request_commit(struct nfs_page *req)
501{
502 return 0;
503}
504
505static inline
506int nfs_write_need_commit(struct nfs_write_data *data)
507{
508 return 0;
509}
510
511static inline
512int nfs_reschedule_unstable_write(struct nfs_page *req,
513 struct nfs_write_data *data)
514{
515 return 0;
516}
517#endif
518
519#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
520static int
521nfs_need_commit(struct nfs_inode *nfsi)
522{
523 return radix_tree_tagged(&nfsi->nfs_page_tree, NFS_PAGE_TAG_COMMIT);
524}
525
526/*
527 * nfs_scan_commit - Scan an inode for commit requests
528 * @inode: NFS inode to scan
529 * @dst: destination list
530 * @idx_start: lower bound of page->index to scan.
531 * @npages: idx_start + npages sets the upper bound to scan.
532 *
533 * Moves requests from the inode's 'commit' request list.
534 * The requests are *not* checked to ensure that they form a contiguous set.
535 */
536static int
537nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
538{
539 struct nfs_inode *nfsi = NFS_I(inode);
540 int ret;
541
542 if (!nfs_need_commit(nfsi))
543 return 0;
544
545 spin_lock(&inode->i_lock);
546 ret = nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
547 if (ret > 0)
548 nfsi->ncommit -= ret;
549 spin_unlock(&inode->i_lock);
550
551 if (nfs_need_commit(NFS_I(inode)))
552 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
553
554 return ret;
555}
556#else
557static inline int nfs_need_commit(struct nfs_inode *nfsi)
558{
559 return 0;
560}
561
562static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
563{
564 return 0;
565}
566#endif
567
568/*
569 * Search for an existing write request, and attempt to update
570 * it to reflect a new dirty region on a given page.
571 *
572 * If the attempt fails, then the existing request is flushed out
573 * to disk.
574 */
575static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
576 struct page *page,
577 unsigned int offset,
578 unsigned int bytes)
579{
580 struct nfs_page *req;
581 unsigned int rqend;
582 unsigned int end;
583 int error;
584
585 if (!PagePrivate(page))
586 return NULL;
587
588 end = offset + bytes;
589 spin_lock(&inode->i_lock);
590
591 for (;;) {
592 req = nfs_page_find_request_locked(page);
593 if (req == NULL)
594 goto out_unlock;
595
596 rqend = req->wb_offset + req->wb_bytes;
597 /*
598 * Tell the caller to flush out the request if
599 * the offsets are non-contiguous.
600 * Note: nfs_flush_incompatible() will already
601 * have flushed out requests having wrong owners.
602 */
603 if (offset > rqend
604 || end < req->wb_offset)
605 goto out_flushme;
606
607 if (nfs_set_page_tag_locked(req))
608 break;
609
610 /* The request is locked, so wait and then retry */
611 spin_unlock(&inode->i_lock);
612 error = nfs_wait_on_request(req);
613 nfs_release_request(req);
614 if (error != 0)
615 goto out_err;
616 spin_lock(&inode->i_lock);
617 }
618
619 if (nfs_clear_request_commit(req) &&
620 radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
621 req->wb_index, NFS_PAGE_TAG_COMMIT) != NULL) {
622 NFS_I(inode)->ncommit--;
623 pnfs_clear_request_commit(req);
624 }
625
626 /* Okay, the request matches. Update the region */
627 if (offset < req->wb_offset) {
628 req->wb_offset = offset;
629 req->wb_pgbase = offset;
630 }
631 if (end > rqend)
632 req->wb_bytes = end - req->wb_offset;
633 else
634 req->wb_bytes = rqend - req->wb_offset;
635out_unlock:
636 spin_unlock(&inode->i_lock);
637 return req;
638out_flushme:
639 spin_unlock(&inode->i_lock);
640 nfs_release_request(req);
641 error = nfs_wb_page(inode, page);
642out_err:
643 return ERR_PTR(error);
644}
645
646/*
647 * Try to update an existing write request, or create one if there is none.
648 *
649 * Note: Should always be called with the Page Lock held to prevent races
650 * if we have to add a new request. Also assumes that the caller has
651 * already called nfs_flush_incompatible() if necessary.
652 */
653static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
654 struct page *page, unsigned int offset, unsigned int bytes)
655{
656 struct inode *inode = page->mapping->host;
657 struct nfs_page *req;
658 int error;
659
660 req = nfs_try_to_update_request(inode, page, offset, bytes);
661 if (req != NULL)
662 goto out;
663 req = nfs_create_request(ctx, inode, page, offset, bytes);
664 if (IS_ERR(req))
665 goto out;
666 error = nfs_inode_add_request(inode, req);
667 if (error != 0) {
668 nfs_release_request(req);
669 req = ERR_PTR(error);
670 }
671out:
672 return req;
673}
674
675static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
676 unsigned int offset, unsigned int count)
677{
678 struct nfs_page *req;
679
680 req = nfs_setup_write_request(ctx, page, offset, count);
681 if (IS_ERR(req))
682 return PTR_ERR(req);
683 /* Update file length */
684 nfs_grow_file(page, offset, count);
685 nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
686 nfs_mark_request_dirty(req);
687 nfs_clear_page_tag_locked(req);
688 return 0;
689}
690
691int nfs_flush_incompatible(struct file *file, struct page *page)
692{
693 struct nfs_open_context *ctx = nfs_file_open_context(file);
694 struct nfs_page *req;
695 int do_flush, status;
696 /*
697 * Look for a request corresponding to this page. If there
698 * is one, and it belongs to another file, we flush it out
699 * before we try to copy anything into the page. Do this
700 * due to the lack of an ACCESS-type call in NFSv2.
701 * Also do the same if we find a request from an existing
702 * dropped page.
703 */
704 do {
705 req = nfs_page_find_request(page);
706 if (req == NULL)
707 return 0;
708 do_flush = req->wb_page != page || req->wb_context != ctx ||
709 req->wb_lock_context->lockowner != current->files ||
710 req->wb_lock_context->pid != current->tgid;
711 nfs_release_request(req);
712 if (!do_flush)
713 return 0;
714 status = nfs_wb_page(page->mapping->host, page);
715 } while (status == 0);
716 return status;
717}
718
719/*
720 * If the page cache is marked as unsafe or invalid, then we can't rely on
721 * the PageUptodate() flag. In this case, we will need to turn off
722 * write optimisations that depend on the page contents being correct.
723 */
724static int nfs_write_pageuptodate(struct page *page, struct inode *inode)
725{
726 return PageUptodate(page) &&
727 !(NFS_I(inode)->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA));
728}
729
730/*
731 * Update and possibly write a cached page of an NFS file.
732 *
733 * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
734 * things with a page scheduled for an RPC call (e.g. invalidate it).
735 */
736int nfs_updatepage(struct file *file, struct page *page,
737 unsigned int offset, unsigned int count)
738{
739 struct nfs_open_context *ctx = nfs_file_open_context(file);
740 struct inode *inode = page->mapping->host;
741 int status = 0;
742
743 nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
744
745 dprintk("NFS: nfs_updatepage(%s/%s %d@%lld)\n",
746 file->f_path.dentry->d_parent->d_name.name,
747 file->f_path.dentry->d_name.name, count,
748 (long long)(page_offset(page) + offset));
749
750 /* If we're not using byte range locks, and we know the page
751 * is up to date, it may be more efficient to extend the write
752 * to cover the entire page in order to avoid fragmentation
753 * inefficiencies.
754 */
755 if (nfs_write_pageuptodate(page, inode) &&
756 inode->i_flock == NULL &&
757 !(file->f_flags & O_DSYNC)) {
758 count = max(count + offset, nfs_page_length(page));
759 offset = 0;
760 }
761
762 status = nfs_writepage_setup(ctx, page, offset, count);
763 if (status < 0)
764 nfs_set_pageerror(page);
765
766 dprintk("NFS: nfs_updatepage returns %d (isize %lld)\n",
767 status, (long long)i_size_read(inode));
768 return status;
769}
770
771static void nfs_writepage_release(struct nfs_page *req,
772 struct nfs_write_data *data)
773{
774 struct page *page = req->wb_page;
775
776 if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req, data))
777 nfs_inode_remove_request(req);
778 nfs_clear_page_tag_locked(req);
779 nfs_end_page_writeback(page);
780}
781
782static int flush_task_priority(int how)
783{
784 switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
785 case FLUSH_HIGHPRI:
786 return RPC_PRIORITY_HIGH;
787 case FLUSH_LOWPRI:
788 return RPC_PRIORITY_LOW;
789 }
790 return RPC_PRIORITY_NORMAL;
791}
792
793int nfs_initiate_write(struct nfs_write_data *data,
794 struct rpc_clnt *clnt,
795 const struct rpc_call_ops *call_ops,
796 int how)
797{
798 struct inode *inode = data->inode;
799 int priority = flush_task_priority(how);
800 struct rpc_task *task;
801 struct rpc_message msg = {
802 .rpc_argp = &data->args,
803 .rpc_resp = &data->res,
804 .rpc_cred = data->cred,
805 };
806 struct rpc_task_setup task_setup_data = {
807 .rpc_client = clnt,
808 .task = &data->task,
809 .rpc_message = &msg,
810 .callback_ops = call_ops,
811 .callback_data = data,
812 .workqueue = nfsiod_workqueue,
813 .flags = RPC_TASK_ASYNC,
814 .priority = priority,
815 };
816 int ret = 0;
817
818 /* Set up the initial task struct. */
819 NFS_PROTO(inode)->write_setup(data, &msg);
820
821 dprintk("NFS: %5u initiated write call "
822 "(req %s/%lld, %u bytes @ offset %llu)\n",
823 data->task.tk_pid,
824 inode->i_sb->s_id,
825 (long long)NFS_FILEID(inode),
826 data->args.count,
827 (unsigned long long)data->args.offset);
828
829 task = rpc_run_task(&task_setup_data);
830 if (IS_ERR(task)) {
831 ret = PTR_ERR(task);
832 goto out;
833 }
834 if (how & FLUSH_SYNC) {
835 ret = rpc_wait_for_completion_task(task);
836 if (ret == 0)
837 ret = task->tk_status;
838 }
839 rpc_put_task(task);
840out:
841 return ret;
842}
843EXPORT_SYMBOL_GPL(nfs_initiate_write);
844
845/*
846 * Set up the argument/result storage required for the RPC call.
847 */
848static void nfs_write_rpcsetup(struct nfs_page *req,
849 struct nfs_write_data *data,
850 unsigned int count, unsigned int offset,
851 int how)
852{
853 struct inode *inode = req->wb_context->dentry->d_inode;
854
855 /* Set up the RPC argument and reply structs
856 * NB: take care not to mess about with data->commit et al. */
857
858 data->req = req;
859 data->inode = inode = req->wb_context->dentry->d_inode;
860 data->cred = req->wb_context->cred;
861
862 data->args.fh = NFS_FH(inode);
863 data->args.offset = req_offset(req) + offset;
864 /* pnfs_set_layoutcommit needs this */
865 data->mds_offset = data->args.offset;
866 data->args.pgbase = req->wb_pgbase + offset;
867 data->args.pages = data->pagevec;
868 data->args.count = count;
869 data->args.context = get_nfs_open_context(req->wb_context);
870 data->args.lock_context = req->wb_lock_context;
871 data->args.stable = NFS_UNSTABLE;
872 switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
873 case 0:
874 break;
875 case FLUSH_COND_STABLE:
876 if (nfs_need_commit(NFS_I(inode)))
877 break;
878 default:
879 data->args.stable = NFS_FILE_SYNC;
880 }
881
882 data->res.fattr = &data->fattr;
883 data->res.count = count;
884 data->res.verf = &data->verf;
885 nfs_fattr_init(&data->fattr);
886}
887
888static int nfs_do_write(struct nfs_write_data *data,
889 const struct rpc_call_ops *call_ops,
890 int how)
891{
892 struct inode *inode = data->args.context->dentry->d_inode;
893
894 return nfs_initiate_write(data, NFS_CLIENT(inode), call_ops, how);
895}
896
897static int nfs_do_multiple_writes(struct list_head *head,
898 const struct rpc_call_ops *call_ops,
899 int how)
900{
901 struct nfs_write_data *data;
902 int ret = 0;
903
904 while (!list_empty(head)) {
905 int ret2;
906
907 data = list_entry(head->next, struct nfs_write_data, list);
908 list_del_init(&data->list);
909
910 ret2 = nfs_do_write(data, call_ops, how);
911 if (ret == 0)
912 ret = ret2;
913 }
914 return ret;
915}
916
917/* If a nfs_flush_* function fails, it should remove reqs from @head and
918 * call this on each, which will prepare them to be retried on next
919 * writeback using standard nfs.
920 */
921static void nfs_redirty_request(struct nfs_page *req)
922{
923 struct page *page = req->wb_page;
924
925 nfs_mark_request_dirty(req);
926 nfs_clear_page_tag_locked(req);
927 nfs_end_page_writeback(page);
928}
929
930/*
931 * Generate multiple small requests to write out a single
932 * contiguous dirty area on one page.
933 */
934static int nfs_flush_multi(struct nfs_pageio_descriptor *desc, struct list_head *res)
935{
936 struct nfs_page *req = nfs_list_entry(desc->pg_list.next);
937 struct page *page = req->wb_page;
938 struct nfs_write_data *data;
939 size_t wsize = desc->pg_bsize, nbytes;
940 unsigned int offset;
941 int requests = 0;
942 int ret = 0;
943
944 nfs_list_remove_request(req);
945
946 if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
947 (desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit ||
948 desc->pg_count > wsize))
949 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
950
951
952 offset = 0;
953 nbytes = desc->pg_count;
954 do {
955 size_t len = min(nbytes, wsize);
956
957 data = nfs_writedata_alloc(1);
958 if (!data)
959 goto out_bad;
960 data->pagevec[0] = page;
961 nfs_write_rpcsetup(req, data, len, offset, desc->pg_ioflags);
962 list_add(&data->list, res);
963 requests++;
964 nbytes -= len;
965 offset += len;
966 } while (nbytes != 0);
967 atomic_set(&req->wb_complete, requests);
968 desc->pg_rpc_callops = &nfs_write_partial_ops;
969 return ret;
970
971out_bad:
972 while (!list_empty(res)) {
973 data = list_entry(res->next, struct nfs_write_data, list);
974 list_del(&data->list);
975 nfs_writedata_free(data);
976 }
977 nfs_redirty_request(req);
978 return -ENOMEM;
979}
980
981/*
982 * Create an RPC task for the given write request and kick it.
983 * The page must have been locked by the caller.
984 *
985 * It may happen that the page we're passed is not marked dirty.
986 * This is the case if nfs_updatepage detects a conflicting request
987 * that has been written but not committed.
988 */
989static int nfs_flush_one(struct nfs_pageio_descriptor *desc, struct list_head *res)
990{
991 struct nfs_page *req;
992 struct page **pages;
993 struct nfs_write_data *data;
994 struct list_head *head = &desc->pg_list;
995 int ret = 0;
996
997 data = nfs_writedata_alloc(nfs_page_array_len(desc->pg_base,
998 desc->pg_count));
999 if (!data) {
1000 while (!list_empty(head)) {
1001 req = nfs_list_entry(head->next);
1002 nfs_list_remove_request(req);
1003 nfs_redirty_request(req);
1004 }
1005 ret = -ENOMEM;
1006 goto out;
1007 }
1008 pages = data->pagevec;
1009 while (!list_empty(head)) {
1010 req = nfs_list_entry(head->next);
1011 nfs_list_remove_request(req);
1012 nfs_list_add_request(req, &data->pages);
1013 ClearPageError(req->wb_page);
1014 *pages++ = req->wb_page;
1015 }
1016 req = nfs_list_entry(data->pages.next);
1017
1018 if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1019 (desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit))
1020 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1021
1022 /* Set up the argument struct */
1023 nfs_write_rpcsetup(req, data, desc->pg_count, 0, desc->pg_ioflags);
1024 list_add(&data->list, res);
1025 desc->pg_rpc_callops = &nfs_write_full_ops;
1026out:
1027 return ret;
1028}
1029
1030int nfs_generic_flush(struct nfs_pageio_descriptor *desc, struct list_head *head)
1031{
1032 if (desc->pg_bsize < PAGE_CACHE_SIZE)
1033 return nfs_flush_multi(desc, head);
1034 return nfs_flush_one(desc, head);
1035}
1036
1037static int nfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
1038{
1039 LIST_HEAD(head);
1040 int ret;
1041
1042 ret = nfs_generic_flush(desc, &head);
1043 if (ret == 0)
1044 ret = nfs_do_multiple_writes(&head, desc->pg_rpc_callops,
1045 desc->pg_ioflags);
1046 return ret;
1047}
1048
1049static const struct nfs_pageio_ops nfs_pageio_write_ops = {
1050 .pg_test = nfs_generic_pg_test,
1051 .pg_doio = nfs_generic_pg_writepages,
1052};
1053
1054static void nfs_pageio_init_write_mds(struct nfs_pageio_descriptor *pgio,
1055 struct inode *inode, int ioflags)
1056{
1057 nfs_pageio_init(pgio, inode, &nfs_pageio_write_ops,
1058 NFS_SERVER(inode)->wsize, ioflags);
1059}
1060
1061void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1062{
1063 pgio->pg_ops = &nfs_pageio_write_ops;
1064 pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1065}
1066EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1067
1068static void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1069 struct inode *inode, int ioflags)
1070{
1071 if (!pnfs_pageio_init_write(pgio, inode, ioflags))
1072 nfs_pageio_init_write_mds(pgio, inode, ioflags);
1073}
1074
1075/*
1076 * Handle a write reply that flushed part of a page.
1077 */
1078static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
1079{
1080 struct nfs_write_data *data = calldata;
1081
1082 dprintk("NFS: %5u write(%s/%lld %d@%lld)",
1083 task->tk_pid,
1084 data->req->wb_context->dentry->d_inode->i_sb->s_id,
1085 (long long)
1086 NFS_FILEID(data->req->wb_context->dentry->d_inode),
1087 data->req->wb_bytes, (long long)req_offset(data->req));
1088
1089 nfs_writeback_done(task, data);
1090}
1091
1092static void nfs_writeback_release_partial(void *calldata)
1093{
1094 struct nfs_write_data *data = calldata;
1095 struct nfs_page *req = data->req;
1096 struct page *page = req->wb_page;
1097 int status = data->task.tk_status;
1098
1099 if (status < 0) {
1100 nfs_set_pageerror(page);
1101 nfs_context_set_write_error(req->wb_context, status);
1102 dprintk(", error = %d\n", status);
1103 goto out;
1104 }
1105
1106 if (nfs_write_need_commit(data)) {
1107 struct inode *inode = page->mapping->host;
1108
1109 spin_lock(&inode->i_lock);
1110 if (test_bit(PG_NEED_RESCHED, &req->wb_flags)) {
1111 /* Do nothing we need to resend the writes */
1112 } else if (!test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags)) {
1113 memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1114 dprintk(" defer commit\n");
1115 } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
1116 set_bit(PG_NEED_RESCHED, &req->wb_flags);
1117 clear_bit(PG_NEED_COMMIT, &req->wb_flags);
1118 dprintk(" server reboot detected\n");
1119 }
1120 spin_unlock(&inode->i_lock);
1121 } else
1122 dprintk(" OK\n");
1123
1124out:
1125 if (atomic_dec_and_test(&req->wb_complete))
1126 nfs_writepage_release(req, data);
1127 nfs_writedata_release(calldata);
1128}
1129
1130#if defined(CONFIG_NFS_V4_1)
1131void nfs_write_prepare(struct rpc_task *task, void *calldata)
1132{
1133 struct nfs_write_data *data = calldata;
1134
1135 if (nfs4_setup_sequence(NFS_SERVER(data->inode),
1136 &data->args.seq_args,
1137 &data->res.seq_res, 1, task))
1138 return;
1139 rpc_call_start(task);
1140}
1141#endif /* CONFIG_NFS_V4_1 */
1142
1143static const struct rpc_call_ops nfs_write_partial_ops = {
1144#if defined(CONFIG_NFS_V4_1)
1145 .rpc_call_prepare = nfs_write_prepare,
1146#endif /* CONFIG_NFS_V4_1 */
1147 .rpc_call_done = nfs_writeback_done_partial,
1148 .rpc_release = nfs_writeback_release_partial,
1149};
1150
1151/*
1152 * Handle a write reply that flushes a whole page.
1153 *
1154 * FIXME: There is an inherent race with invalidate_inode_pages and
1155 * writebacks since the page->count is kept > 1 for as long
1156 * as the page has a write request pending.
1157 */
1158static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
1159{
1160 struct nfs_write_data *data = calldata;
1161
1162 nfs_writeback_done(task, data);
1163}
1164
1165static void nfs_writeback_release_full(void *calldata)
1166{
1167 struct nfs_write_data *data = calldata;
1168 int status = data->task.tk_status;
1169
1170 /* Update attributes as result of writeback. */
1171 while (!list_empty(&data->pages)) {
1172 struct nfs_page *req = nfs_list_entry(data->pages.next);
1173 struct page *page = req->wb_page;
1174
1175 nfs_list_remove_request(req);
1176
1177 dprintk("NFS: %5u write (%s/%lld %d@%lld)",
1178 data->task.tk_pid,
1179 req->wb_context->dentry->d_inode->i_sb->s_id,
1180 (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1181 req->wb_bytes,
1182 (long long)req_offset(req));
1183
1184 if (status < 0) {
1185 nfs_set_pageerror(page);
1186 nfs_context_set_write_error(req->wb_context, status);
1187 dprintk(", error = %d\n", status);
1188 goto remove_request;
1189 }
1190
1191 if (nfs_write_need_commit(data)) {
1192 memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1193 nfs_mark_request_commit(req, data->lseg);
1194 dprintk(" marked for commit\n");
1195 goto next;
1196 }
1197 dprintk(" OK\n");
1198remove_request:
1199 nfs_inode_remove_request(req);
1200 next:
1201 nfs_clear_page_tag_locked(req);
1202 nfs_end_page_writeback(page);
1203 }
1204 nfs_writedata_release(calldata);
1205}
1206
1207static const struct rpc_call_ops nfs_write_full_ops = {
1208#if defined(CONFIG_NFS_V4_1)
1209 .rpc_call_prepare = nfs_write_prepare,
1210#endif /* CONFIG_NFS_V4_1 */
1211 .rpc_call_done = nfs_writeback_done_full,
1212 .rpc_release = nfs_writeback_release_full,
1213};
1214
1215
1216/*
1217 * This function is called when the WRITE call is complete.
1218 */
1219void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
1220{
1221 struct nfs_writeargs *argp = &data->args;
1222 struct nfs_writeres *resp = &data->res;
1223 struct nfs_server *server = NFS_SERVER(data->inode);
1224 int status;
1225
1226 dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1227 task->tk_pid, task->tk_status);
1228
1229 /*
1230 * ->write_done will attempt to use post-op attributes to detect
1231 * conflicting writes by other clients. A strict interpretation
1232 * of close-to-open would allow us to continue caching even if
1233 * another writer had changed the file, but some applications
1234 * depend on tighter cache coherency when writing.
1235 */
1236 status = NFS_PROTO(data->inode)->write_done(task, data);
1237 if (status != 0)
1238 return;
1239 nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1240
1241#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1242 if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1243 /* We tried a write call, but the server did not
1244 * commit data to stable storage even though we
1245 * requested it.
1246 * Note: There is a known bug in Tru64 < 5.0 in which
1247 * the server reports NFS_DATA_SYNC, but performs
1248 * NFS_FILE_SYNC. We therefore implement this checking
1249 * as a dprintk() in order to avoid filling syslog.
1250 */
1251 static unsigned long complain;
1252
1253 /* Note this will print the MDS for a DS write */
1254 if (time_before(complain, jiffies)) {
1255 dprintk("NFS: faulty NFS server %s:"
1256 " (committed = %d) != (stable = %d)\n",
1257 server->nfs_client->cl_hostname,
1258 resp->verf->committed, argp->stable);
1259 complain = jiffies + 300 * HZ;
1260 }
1261 }
1262#endif
1263 /* Is this a short write? */
1264 if (task->tk_status >= 0 && resp->count < argp->count) {
1265 static unsigned long complain;
1266
1267 nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);
1268
1269 /* Has the server at least made some progress? */
1270 if (resp->count != 0) {
1271 /* Was this an NFSv2 write or an NFSv3 stable write? */
1272 if (resp->verf->committed != NFS_UNSTABLE) {
1273 /* Resend from where the server left off */
1274 data->mds_offset += resp->count;
1275 argp->offset += resp->count;
1276 argp->pgbase += resp->count;
1277 argp->count -= resp->count;
1278 } else {
1279 /* Resend as a stable write in order to avoid
1280 * headaches in the case of a server crash.
1281 */
1282 argp->stable = NFS_FILE_SYNC;
1283 }
1284 nfs_restart_rpc(task, server->nfs_client);
1285 return;
1286 }
1287 if (time_before(complain, jiffies)) {
1288 printk(KERN_WARNING
1289 "NFS: Server wrote zero bytes, expected %u.\n",
1290 argp->count);
1291 complain = jiffies + 300 * HZ;
1292 }
1293 /* Can't do anything about it except throw an error. */
1294 task->tk_status = -EIO;
1295 }
1296 return;
1297}
1298
1299
1300#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1301static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait)
1302{
1303 int ret;
1304
1305 if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags))
1306 return 1;
1307 if (!may_wait)
1308 return 0;
1309 ret = out_of_line_wait_on_bit_lock(&nfsi->flags,
1310 NFS_INO_COMMIT,
1311 nfs_wait_bit_killable,
1312 TASK_KILLABLE);
1313 return (ret < 0) ? ret : 1;
1314}
1315
1316void nfs_commit_clear_lock(struct nfs_inode *nfsi)
1317{
1318 clear_bit(NFS_INO_COMMIT, &nfsi->flags);
1319 smp_mb__after_clear_bit();
1320 wake_up_bit(&nfsi->flags, NFS_INO_COMMIT);
1321}
1322EXPORT_SYMBOL_GPL(nfs_commit_clear_lock);
1323
1324void nfs_commitdata_release(void *data)
1325{
1326 struct nfs_write_data *wdata = data;
1327
1328 put_lseg(wdata->lseg);
1329 put_nfs_open_context(wdata->args.context);
1330 nfs_commit_free(wdata);
1331}
1332EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1333
1334int nfs_initiate_commit(struct nfs_write_data *data, struct rpc_clnt *clnt,
1335 const struct rpc_call_ops *call_ops,
1336 int how)
1337{
1338 struct rpc_task *task;
1339 int priority = flush_task_priority(how);
1340 struct rpc_message msg = {
1341 .rpc_argp = &data->args,
1342 .rpc_resp = &data->res,
1343 .rpc_cred = data->cred,
1344 };
1345 struct rpc_task_setup task_setup_data = {
1346 .task = &data->task,
1347 .rpc_client = clnt,
1348 .rpc_message = &msg,
1349 .callback_ops = call_ops,
1350 .callback_data = data,
1351 .workqueue = nfsiod_workqueue,
1352 .flags = RPC_TASK_ASYNC,
1353 .priority = priority,
1354 };
1355 /* Set up the initial task struct. */
1356 NFS_PROTO(data->inode)->commit_setup(data, &msg);
1357
1358 dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1359
1360 task = rpc_run_task(&task_setup_data);
1361 if (IS_ERR(task))
1362 return PTR_ERR(task);
1363 if (how & FLUSH_SYNC)
1364 rpc_wait_for_completion_task(task);
1365 rpc_put_task(task);
1366 return 0;
1367}
1368EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1369
1370/*
1371 * Set up the argument/result storage required for the RPC call.
1372 */
1373void nfs_init_commit(struct nfs_write_data *data,
1374 struct list_head *head,
1375 struct pnfs_layout_segment *lseg)
1376{
1377 struct nfs_page *first = nfs_list_entry(head->next);
1378 struct inode *inode = first->wb_context->dentry->d_inode;
1379
1380 /* Set up the RPC argument and reply structs
1381 * NB: take care not to mess about with data->commit et al. */
1382
1383 list_splice_init(head, &data->pages);
1384
1385 data->inode = inode;
1386 data->cred = first->wb_context->cred;
1387 data->lseg = lseg; /* reference transferred */
1388 data->mds_ops = &nfs_commit_ops;
1389
1390 data->args.fh = NFS_FH(data->inode);
1391 /* Note: we always request a commit of the entire inode */
1392 data->args.offset = 0;
1393 data->args.count = 0;
1394 data->args.context = get_nfs_open_context(first->wb_context);
1395 data->res.count = 0;
1396 data->res.fattr = &data->fattr;
1397 data->res.verf = &data->verf;
1398 nfs_fattr_init(&data->fattr);
1399}
1400EXPORT_SYMBOL_GPL(nfs_init_commit);
1401
1402void nfs_retry_commit(struct list_head *page_list,
1403 struct pnfs_layout_segment *lseg)
1404{
1405 struct nfs_page *req;
1406
1407 while (!list_empty(page_list)) {
1408 req = nfs_list_entry(page_list->next);
1409 nfs_list_remove_request(req);
1410 nfs_mark_request_commit(req, lseg);
1411 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1412 dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
1413 BDI_RECLAIMABLE);
1414 nfs_clear_page_tag_locked(req);
1415 }
1416}
1417EXPORT_SYMBOL_GPL(nfs_retry_commit);
1418
1419/*
1420 * Commit dirty pages
1421 */
1422static int
1423nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1424{
1425 struct nfs_write_data *data;
1426
1427 data = nfs_commitdata_alloc();
1428
1429 if (!data)
1430 goto out_bad;
1431
1432 /* Set up the argument struct */
1433 nfs_init_commit(data, head, NULL);
1434 return nfs_initiate_commit(data, NFS_CLIENT(inode), data->mds_ops, how);
1435 out_bad:
1436 nfs_retry_commit(head, NULL);
1437 nfs_commit_clear_lock(NFS_I(inode));
1438 return -ENOMEM;
1439}
1440
1441/*
1442 * COMMIT call returned
1443 */
1444static void nfs_commit_done(struct rpc_task *task, void *calldata)
1445{
1446 struct nfs_write_data *data = calldata;
1447
1448 dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1449 task->tk_pid, task->tk_status);
1450
1451 /* Call the NFS version-specific code */
1452 NFS_PROTO(data->inode)->commit_done(task, data);
1453}
1454
1455void nfs_commit_release_pages(struct nfs_write_data *data)
1456{
1457 struct nfs_page *req;
1458 int status = data->task.tk_status;
1459
1460 while (!list_empty(&data->pages)) {
1461 req = nfs_list_entry(data->pages.next);
1462 nfs_list_remove_request(req);
1463 nfs_clear_request_commit(req);
1464
1465 dprintk("NFS: commit (%s/%lld %d@%lld)",
1466 req->wb_context->dentry->d_sb->s_id,
1467 (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1468 req->wb_bytes,
1469 (long long)req_offset(req));
1470 if (status < 0) {
1471 nfs_context_set_write_error(req->wb_context, status);
1472 nfs_inode_remove_request(req);
1473 dprintk(", error = %d\n", status);
1474 goto next;
1475 }
1476
1477 /* Okay, COMMIT succeeded, apparently. Check the verifier
1478 * returned by the server against all stored verfs. */
1479 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
1480 /* We have a match */
1481 nfs_inode_remove_request(req);
1482 dprintk(" OK\n");
1483 goto next;
1484 }
1485 /* We have a mismatch. Write the page again */
1486 dprintk(" mismatch\n");
1487 nfs_mark_request_dirty(req);
1488 next:
1489 nfs_clear_page_tag_locked(req);
1490 }
1491}
1492EXPORT_SYMBOL_GPL(nfs_commit_release_pages);
1493
1494static void nfs_commit_release(void *calldata)
1495{
1496 struct nfs_write_data *data = calldata;
1497
1498 nfs_commit_release_pages(data);
1499 nfs_commit_clear_lock(NFS_I(data->inode));
1500 nfs_commitdata_release(calldata);
1501}
1502
1503static const struct rpc_call_ops nfs_commit_ops = {
1504#if defined(CONFIG_NFS_V4_1)
1505 .rpc_call_prepare = nfs_write_prepare,
1506#endif /* CONFIG_NFS_V4_1 */
1507 .rpc_call_done = nfs_commit_done,
1508 .rpc_release = nfs_commit_release,
1509};
1510
1511int nfs_commit_inode(struct inode *inode, int how)
1512{
1513 LIST_HEAD(head);
1514 int may_wait = how & FLUSH_SYNC;
1515 int res;
1516
1517 res = nfs_commit_set_lock(NFS_I(inode), may_wait);
1518 if (res <= 0)
1519 goto out_mark_dirty;
1520 res = nfs_scan_commit(inode, &head, 0, 0);
1521 if (res) {
1522 int error;
1523
1524 error = pnfs_commit_list(inode, &head, how);
1525 if (error == PNFS_NOT_ATTEMPTED)
1526 error = nfs_commit_list(inode, &head, how);
1527 if (error < 0)
1528 return error;
1529 if (!may_wait)
1530 goto out_mark_dirty;
1531 error = wait_on_bit(&NFS_I(inode)->flags,
1532 NFS_INO_COMMIT,
1533 nfs_wait_bit_killable,
1534 TASK_KILLABLE);
1535 if (error < 0)
1536 return error;
1537 } else
1538 nfs_commit_clear_lock(NFS_I(inode));
1539 return res;
1540 /* Note: If we exit without ensuring that the commit is complete,
1541 * we must mark the inode as dirty. Otherwise, future calls to
1542 * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
1543 * that the data is on the disk.
1544 */
1545out_mark_dirty:
1546 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1547 return res;
1548}
1549
1550static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1551{
1552 struct nfs_inode *nfsi = NFS_I(inode);
1553 int flags = FLUSH_SYNC;
1554 int ret = 0;
1555
1556 if (wbc->sync_mode == WB_SYNC_NONE) {
1557 /* Don't commit yet if this is a non-blocking flush and there
1558 * are a lot of outstanding writes for this mapping.
1559 */
1560 if (nfsi->ncommit <= (nfsi->npages >> 1))
1561 goto out_mark_dirty;
1562
1563 /* don't wait for the COMMIT response */
1564 flags = 0;
1565 }
1566
1567 ret = nfs_commit_inode(inode, flags);
1568 if (ret >= 0) {
1569 if (wbc->sync_mode == WB_SYNC_NONE) {
1570 if (ret < wbc->nr_to_write)
1571 wbc->nr_to_write -= ret;
1572 else
1573 wbc->nr_to_write = 0;
1574 }
1575 return 0;
1576 }
1577out_mark_dirty:
1578 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1579 return ret;
1580}
1581#else
1582static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1583{
1584 return 0;
1585}
1586#endif
1587
1588int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1589{
1590 int ret;
1591
1592 ret = nfs_commit_unstable_pages(inode, wbc);
1593 if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
1594 int status;
1595 bool sync = true;
1596
1597 if (wbc->sync_mode == WB_SYNC_NONE)
1598 sync = false;
1599
1600 status = pnfs_layoutcommit_inode(inode, sync);
1601 if (status < 0)
1602 return status;
1603 }
1604 return ret;
1605}
1606
1607/*
1608 * flush the inode to disk.
1609 */
1610int nfs_wb_all(struct inode *inode)
1611{
1612 struct writeback_control wbc = {
1613 .sync_mode = WB_SYNC_ALL,
1614 .nr_to_write = LONG_MAX,
1615 .range_start = 0,
1616 .range_end = LLONG_MAX,
1617 };
1618
1619 return sync_inode(inode, &wbc);
1620}
1621
1622int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1623{
1624 struct nfs_page *req;
1625 int ret = 0;
1626
1627 BUG_ON(!PageLocked(page));
1628 for (;;) {
1629 wait_on_page_writeback(page);
1630 req = nfs_page_find_request(page);
1631 if (req == NULL)
1632 break;
1633 if (nfs_lock_request_dontget(req)) {
1634 nfs_inode_remove_request(req);
1635 /*
1636 * In case nfs_inode_remove_request has marked the
1637 * page as being dirty
1638 */
1639 cancel_dirty_page(page, PAGE_CACHE_SIZE);
1640 nfs_unlock_request(req);
1641 break;
1642 }
1643 ret = nfs_wait_on_request(req);
1644 nfs_release_request(req);
1645 if (ret < 0)
1646 break;
1647 }
1648 return ret;
1649}
1650
1651/*
1652 * Write back all requests on one page - we do this before reading it.
1653 */
1654int nfs_wb_page(struct inode *inode, struct page *page)
1655{
1656 loff_t range_start = page_offset(page);
1657 loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1658 struct writeback_control wbc = {
1659 .sync_mode = WB_SYNC_ALL,
1660 .nr_to_write = 0,
1661 .range_start = range_start,
1662 .range_end = range_end,
1663 };
1664 int ret;
1665
1666 for (;;) {
1667 wait_on_page_writeback(page);
1668 if (clear_page_dirty_for_io(page)) {
1669 ret = nfs_writepage_locked(page, &wbc);
1670 if (ret < 0)
1671 goto out_error;
1672 continue;
1673 }
1674 if (!PagePrivate(page))
1675 break;
1676 ret = nfs_commit_inode(inode, FLUSH_SYNC);
1677 if (ret < 0)
1678 goto out_error;
1679 }
1680 return 0;
1681out_error:
1682 return ret;
1683}
1684
1685#ifdef CONFIG_MIGRATION
1686int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
1687 struct page *page)
1688{
1689 struct nfs_page *req;
1690 int ret;
1691
1692 nfs_fscache_release_page(page, GFP_KERNEL);
1693
1694 req = nfs_find_and_lock_request(page, false);
1695 ret = PTR_ERR(req);
1696 if (IS_ERR(req))
1697 goto out;
1698
1699 ret = migrate_page(mapping, newpage, page);
1700 if (!req)
1701 goto out;
1702 if (ret)
1703 goto out_unlock;
1704 page_cache_get(newpage);
1705 spin_lock(&mapping->host->i_lock);
1706 req->wb_page = newpage;
1707 SetPagePrivate(newpage);
1708 set_page_private(newpage, (unsigned long)req);
1709 ClearPagePrivate(page);
1710 set_page_private(page, 0);
1711 spin_unlock(&mapping->host->i_lock);
1712 page_cache_release(page);
1713out_unlock:
1714 nfs_clear_page_tag_locked(req);
1715out:
1716 return ret;
1717}
1718#endif
1719
1720int __init nfs_init_writepagecache(void)
1721{
1722 nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1723 sizeof(struct nfs_write_data),
1724 0, SLAB_HWCACHE_ALIGN,
1725 NULL);
1726 if (nfs_wdata_cachep == NULL)
1727 return -ENOMEM;
1728
1729 nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1730 nfs_wdata_cachep);
1731 if (nfs_wdata_mempool == NULL)
1732 return -ENOMEM;
1733
1734 nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1735 nfs_wdata_cachep);
1736 if (nfs_commit_mempool == NULL)
1737 return -ENOMEM;
1738
1739 /*
1740 * NFS congestion size, scale with available memory.
1741 *
1742 * 64MB: 8192k
1743 * 128MB: 11585k
1744 * 256MB: 16384k
1745 * 512MB: 23170k
1746 * 1GB: 32768k
1747 * 2GB: 46340k
1748 * 4GB: 65536k
1749 * 8GB: 92681k
1750 * 16GB: 131072k
1751 *
1752 * This allows larger machines to have larger/more transfers.
1753 * Limit the default to 256M
1754 */
1755 nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1756 if (nfs_congestion_kb > 256*1024)
1757 nfs_congestion_kb = 256*1024;
1758
1759 return 0;
1760}
1761
1762void nfs_destroy_writepagecache(void)
1763{
1764 mempool_destroy(nfs_commit_mempool);
1765 mempool_destroy(nfs_wdata_mempool);
1766 kmem_cache_destroy(nfs_wdata_cachep);
1767}
1768