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NFS: Cleanup initialisation of struct nfs_fattr
[linux-2.6.git] / fs / nfs / write.c
1 /*
2  * linux/fs/nfs/write.c
3  *
4  * Writing file data over NFS.
5  *
6  * We do it like this: When a (user) process wishes to write data to an
7  * NFS file, a write request is allocated that contains the RPC task data
8  * plus some info on the page to be written, and added to the inode's
9  * write chain. If the process writes past the end of the page, an async
10  * RPC call to write the page is scheduled immediately; otherwise, the call
11  * is delayed for a few seconds.
12  *
13  * Just like readahead, no async I/O is performed if wsize < PAGE_SIZE.
14  *
15  * Write requests are kept on the inode's writeback list. Each entry in
16  * that list references the page (portion) to be written. When the
17  * cache timeout has expired, the RPC task is woken up, and tries to
18  * lock the page. As soon as it manages to do so, the request is moved
19  * from the writeback list to the writelock list.
20  *
21  * Note: we must make sure never to confuse the inode passed in the
22  * write_page request with the one in page->inode. As far as I understand
23  * it, these are different when doing a swap-out.
24  *
25  * To understand everything that goes on here and in the NFS read code,
26  * one should be aware that a page is locked in exactly one of the following
27  * cases:
28  *
29  *  -   A write request is in progress.
30  *  -   A user process is in generic_file_write/nfs_update_page
31  *  -   A user process is in generic_file_read
32  *
33  * Also note that because of the way pages are invalidated in
34  * nfs_revalidate_inode, the following assertions hold:
35  *
36  *  -   If a page is dirty, there will be no read requests (a page will
37  *      not be re-read unless invalidated by nfs_revalidate_inode).
38  *  -   If the page is not uptodate, there will be no pending write
39  *      requests, and no process will be in nfs_update_page.
40  *
41  * FIXME: Interaction with the vmscan routines is not optimal yet.
42  * Either vmscan must be made nfs-savvy, or we need a different page
43  * reclaim concept that supports something like FS-independent
44  * buffer_heads with a b_ops-> field.
45  *
46  * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
47  */
48
49 #include <linux/config.h>
50 #include <linux/types.h>
51 #include <linux/slab.h>
52 #include <linux/mm.h>
53 #include <linux/pagemap.h>
54 #include <linux/file.h>
55 #include <linux/mpage.h>
56 #include <linux/writeback.h>
57
58 #include <linux/sunrpc/clnt.h>
59 #include <linux/nfs_fs.h>
60 #include <linux/nfs_mount.h>
61 #include <linux/nfs_page.h>
62 #include <asm/uaccess.h>
63 #include <linux/smp_lock.h>
64
65 #include "delegation.h"
66
67 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
68
69 #define MIN_POOL_WRITE          (32)
70 #define MIN_POOL_COMMIT         (4)
71
72 /*
73  * Local function declarations
74  */
75 static struct nfs_page * nfs_update_request(struct nfs_open_context*,
76                                             struct inode *,
77                                             struct page *,
78                                             unsigned int, unsigned int);
79 static void nfs_writeback_done_partial(struct nfs_write_data *, int);
80 static void nfs_writeback_done_full(struct nfs_write_data *, int);
81 static int nfs_wait_on_write_congestion(struct address_space *, int);
82 static int nfs_wait_on_requests(struct inode *, unsigned long, unsigned int);
83 static int nfs_flush_inode(struct inode *inode, unsigned long idx_start,
84                            unsigned int npages, int how);
85
86 static kmem_cache_t *nfs_wdata_cachep;
87 mempool_t *nfs_wdata_mempool;
88 static mempool_t *nfs_commit_mempool;
89
90 static DECLARE_WAIT_QUEUE_HEAD(nfs_write_congestion);
91
92 static inline struct nfs_write_data *nfs_commit_alloc(void)
93 {
94         struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, SLAB_NOFS);
95         if (p) {
96                 memset(p, 0, sizeof(*p));
97                 INIT_LIST_HEAD(&p->pages);
98         }
99         return p;
100 }
101
102 static inline void nfs_commit_free(struct nfs_write_data *p)
103 {
104         mempool_free(p, nfs_commit_mempool);
105 }
106
107 static void nfs_writedata_release(struct rpc_task *task)
108 {
109         struct nfs_write_data   *wdata = (struct nfs_write_data *)task->tk_calldata;
110         nfs_writedata_free(wdata);
111 }
112
113 /* Adjust the file length if we're writing beyond the end */
114 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
115 {
116         struct inode *inode = page->mapping->host;
117         loff_t end, i_size = i_size_read(inode);
118         unsigned long end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
119
120         if (i_size > 0 && page->index < end_index)
121                 return;
122         end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
123         if (i_size >= end)
124                 return;
125         i_size_write(inode, end);
126 }
127
128 /* We can set the PG_uptodate flag if we see that a write request
129  * covers the full page.
130  */
131 static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
132 {
133         loff_t end_offs;
134
135         if (PageUptodate(page))
136                 return;
137         if (base != 0)
138                 return;
139         if (count == PAGE_CACHE_SIZE) {
140                 SetPageUptodate(page);
141                 return;
142         }
143
144         end_offs = i_size_read(page->mapping->host) - 1;
145         if (end_offs < 0)
146                 return;
147         /* Is this the last page? */
148         if (page->index != (unsigned long)(end_offs >> PAGE_CACHE_SHIFT))
149                 return;
150         /* This is the last page: set PG_uptodate if we cover the entire
151          * extent of the data, then zero the rest of the page.
152          */
153         if (count == (unsigned int)(end_offs & (PAGE_CACHE_SIZE - 1)) + 1) {
154                 memclear_highpage_flush(page, count, PAGE_CACHE_SIZE - count);
155                 SetPageUptodate(page);
156         }
157 }
158
159 /*
160  * Write a page synchronously.
161  * Offset is the data offset within the page.
162  */
163 static int nfs_writepage_sync(struct nfs_open_context *ctx, struct inode *inode,
164                 struct page *page, unsigned int offset, unsigned int count,
165                 int how)
166 {
167         unsigned int    wsize = NFS_SERVER(inode)->wsize;
168         int             result, written = 0;
169         struct nfs_write_data *wdata;
170
171         wdata = nfs_writedata_alloc();
172         if (!wdata)
173                 return -ENOMEM;
174
175         wdata->flags = how;
176         wdata->cred = ctx->cred;
177         wdata->inode = inode;
178         wdata->args.fh = NFS_FH(inode);
179         wdata->args.context = ctx;
180         wdata->args.pages = &page;
181         wdata->args.stable = NFS_FILE_SYNC;
182         wdata->args.pgbase = offset;
183         wdata->args.count = wsize;
184         wdata->res.fattr = &wdata->fattr;
185         wdata->res.verf = &wdata->verf;
186
187         dprintk("NFS:      nfs_writepage_sync(%s/%Ld %d@%Ld)\n",
188                 inode->i_sb->s_id,
189                 (long long)NFS_FILEID(inode),
190                 count, (long long)(page_offset(page) + offset));
191
192         nfs_begin_data_update(inode);
193         do {
194                 if (count < wsize)
195                         wdata->args.count = count;
196                 wdata->args.offset = page_offset(page) + wdata->args.pgbase;
197
198                 result = NFS_PROTO(inode)->write(wdata);
199
200                 if (result < 0) {
201                         /* Must mark the page invalid after I/O error */
202                         ClearPageUptodate(page);
203                         goto io_error;
204                 }
205                 if (result < wdata->args.count)
206                         printk(KERN_WARNING "NFS: short write, count=%u, result=%d\n",
207                                         wdata->args.count, result);
208
209                 wdata->args.offset += result;
210                 wdata->args.pgbase += result;
211                 written += result;
212                 count -= result;
213         } while (count);
214         /* Update file length */
215         nfs_grow_file(page, offset, written);
216         /* Set the PG_uptodate flag? */
217         nfs_mark_uptodate(page, offset, written);
218
219         if (PageError(page))
220                 ClearPageError(page);
221
222 io_error:
223         nfs_end_data_update(inode);
224         nfs_writedata_free(wdata);
225         return written ? written : result;
226 }
227
228 static int nfs_writepage_async(struct nfs_open_context *ctx,
229                 struct inode *inode, struct page *page,
230                 unsigned int offset, unsigned int count)
231 {
232         struct nfs_page *req;
233         int             status;
234
235         req = nfs_update_request(ctx, inode, page, offset, count);
236         status = (IS_ERR(req)) ? PTR_ERR(req) : 0;
237         if (status < 0)
238                 goto out;
239         /* Update file length */
240         nfs_grow_file(page, offset, count);
241         /* Set the PG_uptodate flag? */
242         nfs_mark_uptodate(page, offset, count);
243         nfs_unlock_request(req);
244  out:
245         return status;
246 }
247
248 static int wb_priority(struct writeback_control *wbc)
249 {
250         if (wbc->for_reclaim)
251                 return FLUSH_HIGHPRI;
252         if (wbc->for_kupdate)
253                 return FLUSH_LOWPRI;
254         return 0;
255 }
256
257 /*
258  * Write an mmapped page to the server.
259  */
260 int nfs_writepage(struct page *page, struct writeback_control *wbc)
261 {
262         struct nfs_open_context *ctx;
263         struct inode *inode = page->mapping->host;
264         unsigned long end_index;
265         unsigned offset = PAGE_CACHE_SIZE;
266         loff_t i_size = i_size_read(inode);
267         int inode_referenced = 0;
268         int priority = wb_priority(wbc);
269         int err;
270
271         /*
272          * Note: We need to ensure that we have a reference to the inode
273          *       if we are to do asynchronous writes. If not, waiting
274          *       in nfs_wait_on_request() may deadlock with clear_inode().
275          *
276          *       If igrab() fails here, then it is in any case safe to
277          *       call nfs_wb_page(), since there will be no pending writes.
278          */
279         if (igrab(inode) != 0)
280                 inode_referenced = 1;
281         end_index = i_size >> PAGE_CACHE_SHIFT;
282
283         /* Ensure we've flushed out any previous writes */
284         nfs_wb_page_priority(inode, page, priority);
285
286         /* easy case */
287         if (page->index < end_index)
288                 goto do_it;
289         /* things got complicated... */
290         offset = i_size & (PAGE_CACHE_SIZE-1);
291
292         /* OK, are we completely out? */
293         err = 0; /* potential race with truncate - ignore */
294         if (page->index >= end_index+1 || !offset)
295                 goto out;
296 do_it:
297         ctx = nfs_find_open_context(inode, FMODE_WRITE);
298         if (ctx == NULL) {
299                 err = -EBADF;
300                 goto out;
301         }
302         lock_kernel();
303         if (!IS_SYNC(inode) && inode_referenced) {
304                 err = nfs_writepage_async(ctx, inode, page, 0, offset);
305                 if (err >= 0) {
306                         err = 0;
307                         if (wbc->for_reclaim)
308                                 nfs_flush_inode(inode, 0, 0, FLUSH_STABLE);
309                 }
310         } else {
311                 err = nfs_writepage_sync(ctx, inode, page, 0,
312                                                 offset, priority);
313                 if (err >= 0) {
314                         if (err != offset)
315                                 redirty_page_for_writepage(wbc, page);
316                         err = 0;
317                 }
318         }
319         unlock_kernel();
320         put_nfs_open_context(ctx);
321 out:
322         unlock_page(page);
323         if (inode_referenced)
324                 iput(inode);
325         return err; 
326 }
327
328 /*
329  * Note: causes nfs_update_request() to block on the assumption
330  *       that the writeback is generated due to memory pressure.
331  */
332 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
333 {
334         struct backing_dev_info *bdi = mapping->backing_dev_info;
335         struct inode *inode = mapping->host;
336         int err;
337
338         err = generic_writepages(mapping, wbc);
339         if (err)
340                 return err;
341         while (test_and_set_bit(BDI_write_congested, &bdi->state) != 0) {
342                 if (wbc->nonblocking)
343                         return 0;
344                 nfs_wait_on_write_congestion(mapping, 0);
345         }
346         err = nfs_flush_inode(inode, 0, 0, wb_priority(wbc));
347         if (err < 0)
348                 goto out;
349         wbc->nr_to_write -= err;
350         if (!wbc->nonblocking && wbc->sync_mode == WB_SYNC_ALL) {
351                 err = nfs_wait_on_requests(inode, 0, 0);
352                 if (err < 0)
353                         goto out;
354         }
355         err = nfs_commit_inode(inode, wb_priority(wbc));
356         if (err > 0) {
357                 wbc->nr_to_write -= err;
358                 err = 0;
359         }
360 out:
361         clear_bit(BDI_write_congested, &bdi->state);
362         wake_up_all(&nfs_write_congestion);
363         return err;
364 }
365
366 /*
367  * Insert a write request into an inode
368  */
369 static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
370 {
371         struct nfs_inode *nfsi = NFS_I(inode);
372         int error;
373
374         error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
375         BUG_ON(error == -EEXIST);
376         if (error)
377                 return error;
378         if (!nfsi->npages) {
379                 igrab(inode);
380                 nfs_begin_data_update(inode);
381                 if (nfs_have_delegation(inode, FMODE_WRITE))
382                         nfsi->change_attr++;
383         }
384         nfsi->npages++;
385         atomic_inc(&req->wb_count);
386         return 0;
387 }
388
389 /*
390  * Insert a write request into an inode
391  */
392 static void nfs_inode_remove_request(struct nfs_page *req)
393 {
394         struct inode *inode = req->wb_context->dentry->d_inode;
395         struct nfs_inode *nfsi = NFS_I(inode);
396
397         BUG_ON (!NFS_WBACK_BUSY(req));
398
399         spin_lock(&nfsi->req_lock);
400         radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
401         nfsi->npages--;
402         if (!nfsi->npages) {
403                 spin_unlock(&nfsi->req_lock);
404                 nfs_end_data_update(inode);
405                 iput(inode);
406         } else
407                 spin_unlock(&nfsi->req_lock);
408         nfs_clear_request(req);
409         nfs_release_request(req);
410 }
411
412 /*
413  * Find a request
414  */
415 static inline struct nfs_page *
416 _nfs_find_request(struct inode *inode, unsigned long index)
417 {
418         struct nfs_inode *nfsi = NFS_I(inode);
419         struct nfs_page *req;
420
421         req = (struct nfs_page*)radix_tree_lookup(&nfsi->nfs_page_tree, index);
422         if (req)
423                 atomic_inc(&req->wb_count);
424         return req;
425 }
426
427 static struct nfs_page *
428 nfs_find_request(struct inode *inode, unsigned long index)
429 {
430         struct nfs_page         *req;
431         struct nfs_inode        *nfsi = NFS_I(inode);
432
433         spin_lock(&nfsi->req_lock);
434         req = _nfs_find_request(inode, index);
435         spin_unlock(&nfsi->req_lock);
436         return req;
437 }
438
439 /*
440  * Add a request to the inode's dirty list.
441  */
442 static void
443 nfs_mark_request_dirty(struct nfs_page *req)
444 {
445         struct inode *inode = req->wb_context->dentry->d_inode;
446         struct nfs_inode *nfsi = NFS_I(inode);
447
448         spin_lock(&nfsi->req_lock);
449         radix_tree_tag_set(&nfsi->nfs_page_tree,
450                         req->wb_index, NFS_PAGE_TAG_DIRTY);
451         nfs_list_add_request(req, &nfsi->dirty);
452         nfsi->ndirty++;
453         spin_unlock(&nfsi->req_lock);
454         inc_page_state(nr_dirty);
455         mark_inode_dirty(inode);
456 }
457
458 /*
459  * Check if a request is dirty
460  */
461 static inline int
462 nfs_dirty_request(struct nfs_page *req)
463 {
464         struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode);
465         return !list_empty(&req->wb_list) && req->wb_list_head == &nfsi->dirty;
466 }
467
468 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
469 /*
470  * Add a request to the inode's commit list.
471  */
472 static void
473 nfs_mark_request_commit(struct nfs_page *req)
474 {
475         struct inode *inode = req->wb_context->dentry->d_inode;
476         struct nfs_inode *nfsi = NFS_I(inode);
477
478         spin_lock(&nfsi->req_lock);
479         nfs_list_add_request(req, &nfsi->commit);
480         nfsi->ncommit++;
481         spin_unlock(&nfsi->req_lock);
482         inc_page_state(nr_unstable);
483         mark_inode_dirty(inode);
484 }
485 #endif
486
487 /*
488  * Wait for a request to complete.
489  *
490  * Interruptible by signals only if mounted with intr flag.
491  */
492 static int
493 nfs_wait_on_requests(struct inode *inode, unsigned long idx_start, unsigned int npages)
494 {
495         struct nfs_inode *nfsi = NFS_I(inode);
496         struct nfs_page *req;
497         unsigned long           idx_end, next;
498         unsigned int            res = 0;
499         int                     error;
500
501         if (npages == 0)
502                 idx_end = ~0;
503         else
504                 idx_end = idx_start + npages - 1;
505
506         spin_lock(&nfsi->req_lock);
507         next = idx_start;
508         while (radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree, (void **)&req, next, 1, NFS_PAGE_TAG_WRITEBACK)) {
509                 if (req->wb_index > idx_end)
510                         break;
511
512                 next = req->wb_index + 1;
513                 BUG_ON(!NFS_WBACK_BUSY(req));
514
515                 atomic_inc(&req->wb_count);
516                 spin_unlock(&nfsi->req_lock);
517                 error = nfs_wait_on_request(req);
518                 nfs_release_request(req);
519                 if (error < 0)
520                         return error;
521                 spin_lock(&nfsi->req_lock);
522                 res++;
523         }
524         spin_unlock(&nfsi->req_lock);
525         return res;
526 }
527
528 /*
529  * nfs_scan_dirty - Scan an inode for dirty requests
530  * @inode: NFS inode to scan
531  * @dst: destination list
532  * @idx_start: lower bound of page->index to scan.
533  * @npages: idx_start + npages sets the upper bound to scan.
534  *
535  * Moves requests from the inode's dirty page list.
536  * The requests are *not* checked to ensure that they form a contiguous set.
537  */
538 static int
539 nfs_scan_dirty(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
540 {
541         struct nfs_inode *nfsi = NFS_I(inode);
542         int res = 0;
543
544         if (nfsi->ndirty != 0) {
545                 res = nfs_scan_lock_dirty(nfsi, dst, idx_start, npages);
546                 nfsi->ndirty -= res;
547                 sub_page_state(nr_dirty,res);
548                 if ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty))
549                         printk(KERN_ERR "NFS: desynchronized value of nfs_i.ndirty.\n");
550         }
551         return res;
552 }
553
554 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
555 /*
556  * nfs_scan_commit - Scan an inode for commit requests
557  * @inode: NFS inode to scan
558  * @dst: destination list
559  * @idx_start: lower bound of page->index to scan.
560  * @npages: idx_start + npages sets the upper bound to scan.
561  *
562  * Moves requests from the inode's 'commit' request list.
563  * The requests are *not* checked to ensure that they form a contiguous set.
564  */
565 static int
566 nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
567 {
568         struct nfs_inode *nfsi = NFS_I(inode);
569         int res = 0;
570
571         if (nfsi->ncommit != 0) {
572                 res = nfs_scan_list(&nfsi->commit, dst, idx_start, npages);
573                 nfsi->ncommit -= res;
574                 if ((nfsi->ncommit == 0) != list_empty(&nfsi->commit))
575                         printk(KERN_ERR "NFS: desynchronized value of nfs_i.ncommit.\n");
576         }
577         return res;
578 }
579 #endif
580
581 static int nfs_wait_on_write_congestion(struct address_space *mapping, int intr)
582 {
583         struct backing_dev_info *bdi = mapping->backing_dev_info;
584         DEFINE_WAIT(wait);
585         int ret = 0;
586
587         might_sleep();
588
589         if (!bdi_write_congested(bdi))
590                 return 0;
591         if (intr) {
592                 struct rpc_clnt *clnt = NFS_CLIENT(mapping->host);
593                 sigset_t oldset;
594
595                 rpc_clnt_sigmask(clnt, &oldset);
596                 prepare_to_wait(&nfs_write_congestion, &wait, TASK_INTERRUPTIBLE);
597                 if (bdi_write_congested(bdi)) {
598                         if (signalled())
599                                 ret = -ERESTARTSYS;
600                         else
601                                 schedule();
602                 }
603                 rpc_clnt_sigunmask(clnt, &oldset);
604         } else {
605                 prepare_to_wait(&nfs_write_congestion, &wait, TASK_UNINTERRUPTIBLE);
606                 if (bdi_write_congested(bdi))
607                         schedule();
608         }
609         finish_wait(&nfs_write_congestion, &wait);
610         return ret;
611 }
612
613
614 /*
615  * Try to update any existing write request, or create one if there is none.
616  * In order to match, the request's credentials must match those of
617  * the calling process.
618  *
619  * Note: Should always be called with the Page Lock held!
620  */
621 static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
622                 struct inode *inode, struct page *page,
623                 unsigned int offset, unsigned int bytes)
624 {
625         struct nfs_server *server = NFS_SERVER(inode);
626         struct nfs_inode *nfsi = NFS_I(inode);
627         struct nfs_page         *req, *new = NULL;
628         unsigned long           rqend, end;
629
630         end = offset + bytes;
631
632         if (nfs_wait_on_write_congestion(page->mapping, server->flags & NFS_MOUNT_INTR))
633                 return ERR_PTR(-ERESTARTSYS);
634         for (;;) {
635                 /* Loop over all inode entries and see if we find
636                  * A request for the page we wish to update
637                  */
638                 spin_lock(&nfsi->req_lock);
639                 req = _nfs_find_request(inode, page->index);
640                 if (req) {
641                         if (!nfs_lock_request_dontget(req)) {
642                                 int error;
643                                 spin_unlock(&nfsi->req_lock);
644                                 error = nfs_wait_on_request(req);
645                                 nfs_release_request(req);
646                                 if (error < 0)
647                                         return ERR_PTR(error);
648                                 continue;
649                         }
650                         spin_unlock(&nfsi->req_lock);
651                         if (new)
652                                 nfs_release_request(new);
653                         break;
654                 }
655
656                 if (new) {
657                         int error;
658                         nfs_lock_request_dontget(new);
659                         error = nfs_inode_add_request(inode, new);
660                         if (error) {
661                                 spin_unlock(&nfsi->req_lock);
662                                 nfs_unlock_request(new);
663                                 return ERR_PTR(error);
664                         }
665                         spin_unlock(&nfsi->req_lock);
666                         nfs_mark_request_dirty(new);
667                         return new;
668                 }
669                 spin_unlock(&nfsi->req_lock);
670
671                 new = nfs_create_request(ctx, inode, page, offset, bytes);
672                 if (IS_ERR(new))
673                         return new;
674         }
675
676         /* We have a request for our page.
677          * If the creds don't match, or the
678          * page addresses don't match,
679          * tell the caller to wait on the conflicting
680          * request.
681          */
682         rqend = req->wb_offset + req->wb_bytes;
683         if (req->wb_context != ctx
684             || req->wb_page != page
685             || !nfs_dirty_request(req)
686             || offset > rqend || end < req->wb_offset) {
687                 nfs_unlock_request(req);
688                 return ERR_PTR(-EBUSY);
689         }
690
691         /* Okay, the request matches. Update the region */
692         if (offset < req->wb_offset) {
693                 req->wb_offset = offset;
694                 req->wb_pgbase = offset;
695                 req->wb_bytes = rqend - req->wb_offset;
696         }
697
698         if (end > rqend)
699                 req->wb_bytes = end - req->wb_offset;
700
701         return req;
702 }
703
704 int nfs_flush_incompatible(struct file *file, struct page *page)
705 {
706         struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
707         struct inode    *inode = page->mapping->host;
708         struct nfs_page *req;
709         int             status = 0;
710         /*
711          * Look for a request corresponding to this page. If there
712          * is one, and it belongs to another file, we flush it out
713          * before we try to copy anything into the page. Do this
714          * due to the lack of an ACCESS-type call in NFSv2.
715          * Also do the same if we find a request from an existing
716          * dropped page.
717          */
718         req = nfs_find_request(inode, page->index);
719         if (req) {
720                 if (req->wb_page != page || ctx != req->wb_context)
721                         status = nfs_wb_page(inode, page);
722                 nfs_release_request(req);
723         }
724         return (status < 0) ? status : 0;
725 }
726
727 /*
728  * Update and possibly write a cached page of an NFS file.
729  *
730  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
731  * things with a page scheduled for an RPC call (e.g. invalidate it).
732  */
733 int nfs_updatepage(struct file *file, struct page *page,
734                 unsigned int offset, unsigned int count)
735 {
736         struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
737         struct dentry   *dentry = file->f_dentry;
738         struct inode    *inode = page->mapping->host;
739         struct nfs_page *req;
740         int             status = 0;
741
742         dprintk("NFS:      nfs_updatepage(%s/%s %d@%Ld)\n",
743                 dentry->d_parent->d_name.name, dentry->d_name.name,
744                 count, (long long)(page_offset(page) +offset));
745
746         if (IS_SYNC(inode)) {
747                 status = nfs_writepage_sync(ctx, inode, page, offset, count, 0);
748                 if (status > 0) {
749                         if (offset == 0 && status == PAGE_CACHE_SIZE)
750                                 SetPageUptodate(page);
751                         return 0;
752                 }
753                 return status;
754         }
755
756         /* If we're not using byte range locks, and we know the page
757          * is entirely in cache, it may be more efficient to avoid
758          * fragmenting write requests.
759          */
760         if (PageUptodate(page) && inode->i_flock == NULL && !(file->f_mode & O_SYNC)) {
761                 loff_t end_offs = i_size_read(inode) - 1;
762                 unsigned long end_index = end_offs >> PAGE_CACHE_SHIFT;
763
764                 count += offset;
765                 offset = 0;
766                 if (unlikely(end_offs < 0)) {
767                         /* Do nothing */
768                 } else if (page->index == end_index) {
769                         unsigned int pglen;
770                         pglen = (unsigned int)(end_offs & (PAGE_CACHE_SIZE-1)) + 1;
771                         if (count < pglen)
772                                 count = pglen;
773                 } else if (page->index < end_index)
774                         count = PAGE_CACHE_SIZE;
775         }
776
777         /*
778          * Try to find an NFS request corresponding to this page
779          * and update it.
780          * If the existing request cannot be updated, we must flush
781          * it out now.
782          */
783         do {
784                 req = nfs_update_request(ctx, inode, page, offset, count);
785                 status = (IS_ERR(req)) ? PTR_ERR(req) : 0;
786                 if (status != -EBUSY)
787                         break;
788                 /* Request could not be updated. Flush it out and try again */
789                 status = nfs_wb_page(inode, page);
790         } while (status >= 0);
791         if (status < 0)
792                 goto done;
793
794         status = 0;
795
796         /* Update file length */
797         nfs_grow_file(page, offset, count);
798         /* Set the PG_uptodate flag? */
799         nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
800         nfs_unlock_request(req);
801 done:
802         dprintk("NFS:      nfs_updatepage returns %d (isize %Ld)\n",
803                         status, (long long)i_size_read(inode));
804         if (status < 0)
805                 ClearPageUptodate(page);
806         return status;
807 }
808
809 static void nfs_writepage_release(struct nfs_page *req)
810 {
811         end_page_writeback(req->wb_page);
812
813 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
814         if (!PageError(req->wb_page)) {
815                 if (NFS_NEED_RESCHED(req)) {
816                         nfs_mark_request_dirty(req);
817                         goto out;
818                 } else if (NFS_NEED_COMMIT(req)) {
819                         nfs_mark_request_commit(req);
820                         goto out;
821                 }
822         }
823         nfs_inode_remove_request(req);
824
825 out:
826         nfs_clear_commit(req);
827         nfs_clear_reschedule(req);
828 #else
829         nfs_inode_remove_request(req);
830 #endif
831         nfs_clear_page_writeback(req);
832 }
833
834 static inline int flush_task_priority(int how)
835 {
836         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
837                 case FLUSH_HIGHPRI:
838                         return RPC_PRIORITY_HIGH;
839                 case FLUSH_LOWPRI:
840                         return RPC_PRIORITY_LOW;
841         }
842         return RPC_PRIORITY_NORMAL;
843 }
844
845 /*
846  * Set up the argument/result storage required for the RPC call.
847  */
848 static 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 rpc_task         *task = &data->task;
854         struct inode            *inode;
855
856         /* Set up the RPC argument and reply structs
857          * NB: take care not to mess about with data->commit et al. */
858
859         data->req = req;
860         data->inode = inode = req->wb_context->dentry->d_inode;
861         data->cred = req->wb_context->cred;
862
863         data->args.fh     = NFS_FH(inode);
864         data->args.offset = req_offset(req) + offset;
865         data->args.pgbase = req->wb_pgbase + offset;
866         data->args.pages  = data->pagevec;
867         data->args.count  = count;
868         data->args.context = req->wb_context;
869
870         data->res.fattr   = &data->fattr;
871         data->res.count   = count;
872         data->res.verf    = &data->verf;
873         nfs_fattr_init(&data->fattr);
874
875         NFS_PROTO(inode)->write_setup(data, how);
876
877         data->task.tk_priority = flush_task_priority(how);
878         data->task.tk_cookie = (unsigned long)inode;
879         data->task.tk_calldata = data;
880         /* Release requests */
881         data->task.tk_release = nfs_writedata_release;
882
883         dprintk("NFS: %4d initiated write call (req %s/%Ld, %u bytes @ offset %Lu)\n",
884                 task->tk_pid,
885                 inode->i_sb->s_id,
886                 (long long)NFS_FILEID(inode),
887                 count,
888                 (unsigned long long)data->args.offset);
889 }
890
891 static void nfs_execute_write(struct nfs_write_data *data)
892 {
893         struct rpc_clnt *clnt = NFS_CLIENT(data->inode);
894         sigset_t oldset;
895
896         rpc_clnt_sigmask(clnt, &oldset);
897         lock_kernel();
898         rpc_execute(&data->task);
899         unlock_kernel();
900         rpc_clnt_sigunmask(clnt, &oldset);
901 }
902
903 /*
904  * Generate multiple small requests to write out a single
905  * contiguous dirty area on one page.
906  */
907 static int nfs_flush_multi(struct list_head *head, struct inode *inode, int how)
908 {
909         struct nfs_page *req = nfs_list_entry(head->next);
910         struct page *page = req->wb_page;
911         struct nfs_write_data *data;
912         unsigned int wsize = NFS_SERVER(inode)->wsize;
913         unsigned int nbytes, offset;
914         int requests = 0;
915         LIST_HEAD(list);
916
917         nfs_list_remove_request(req);
918
919         nbytes = req->wb_bytes;
920         for (;;) {
921                 data = nfs_writedata_alloc();
922                 if (!data)
923                         goto out_bad;
924                 list_add(&data->pages, &list);
925                 requests++;
926                 if (nbytes <= wsize)
927                         break;
928                 nbytes -= wsize;
929         }
930         atomic_set(&req->wb_complete, requests);
931
932         ClearPageError(page);
933         SetPageWriteback(page);
934         offset = 0;
935         nbytes = req->wb_bytes;
936         do {
937                 data = list_entry(list.next, struct nfs_write_data, pages);
938                 list_del_init(&data->pages);
939
940                 data->pagevec[0] = page;
941                 data->complete = nfs_writeback_done_partial;
942
943                 if (nbytes > wsize) {
944                         nfs_write_rpcsetup(req, data, wsize, offset, how);
945                         offset += wsize;
946                         nbytes -= wsize;
947                 } else {
948                         nfs_write_rpcsetup(req, data, nbytes, offset, how);
949                         nbytes = 0;
950                 }
951                 nfs_execute_write(data);
952         } while (nbytes != 0);
953
954         return 0;
955
956 out_bad:
957         while (!list_empty(&list)) {
958                 data = list_entry(list.next, struct nfs_write_data, pages);
959                 list_del(&data->pages);
960                 nfs_writedata_free(data);
961         }
962         nfs_mark_request_dirty(req);
963         nfs_clear_page_writeback(req);
964         return -ENOMEM;
965 }
966
967 /*
968  * Create an RPC task for the given write request and kick it.
969  * The page must have been locked by the caller.
970  *
971  * It may happen that the page we're passed is not marked dirty.
972  * This is the case if nfs_updatepage detects a conflicting request
973  * that has been written but not committed.
974  */
975 static int nfs_flush_one(struct list_head *head, struct inode *inode, int how)
976 {
977         struct nfs_page         *req;
978         struct page             **pages;
979         struct nfs_write_data   *data;
980         unsigned int            count;
981
982         if (NFS_SERVER(inode)->wsize < PAGE_CACHE_SIZE)
983                 return nfs_flush_multi(head, inode, how);
984
985         data = nfs_writedata_alloc();
986         if (!data)
987                 goto out_bad;
988
989         pages = data->pagevec;
990         count = 0;
991         while (!list_empty(head)) {
992                 req = nfs_list_entry(head->next);
993                 nfs_list_remove_request(req);
994                 nfs_list_add_request(req, &data->pages);
995                 ClearPageError(req->wb_page);
996                 SetPageWriteback(req->wb_page);
997                 *pages++ = req->wb_page;
998                 count += req->wb_bytes;
999         }
1000         req = nfs_list_entry(data->pages.next);
1001
1002         data->complete = nfs_writeback_done_full;
1003         /* Set up the argument struct */
1004         nfs_write_rpcsetup(req, data, count, 0, how);
1005
1006         nfs_execute_write(data);
1007         return 0;
1008  out_bad:
1009         while (!list_empty(head)) {
1010                 struct nfs_page *req = nfs_list_entry(head->next);
1011                 nfs_list_remove_request(req);
1012                 nfs_mark_request_dirty(req);
1013                 nfs_clear_page_writeback(req);
1014         }
1015         return -ENOMEM;
1016 }
1017
1018 static int
1019 nfs_flush_list(struct list_head *head, int wpages, int how)
1020 {
1021         LIST_HEAD(one_request);
1022         struct nfs_page         *req;
1023         int                     error = 0;
1024         unsigned int            pages = 0;
1025
1026         while (!list_empty(head)) {
1027                 pages += nfs_coalesce_requests(head, &one_request, wpages);
1028                 req = nfs_list_entry(one_request.next);
1029                 error = nfs_flush_one(&one_request, req->wb_context->dentry->d_inode, how);
1030                 if (error < 0)
1031                         break;
1032         }
1033         if (error >= 0)
1034                 return pages;
1035
1036         while (!list_empty(head)) {
1037                 req = nfs_list_entry(head->next);
1038                 nfs_list_remove_request(req);
1039                 nfs_mark_request_dirty(req);
1040                 nfs_clear_page_writeback(req);
1041         }
1042         return error;
1043 }
1044
1045 /*
1046  * Handle a write reply that flushed part of a page.
1047  */
1048 static void nfs_writeback_done_partial(struct nfs_write_data *data, int status)
1049 {
1050         struct nfs_page         *req = data->req;
1051         struct page             *page = req->wb_page;
1052
1053         dprintk("NFS: write (%s/%Ld %d@%Ld)",
1054                 req->wb_context->dentry->d_inode->i_sb->s_id,
1055                 (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1056                 req->wb_bytes,
1057                 (long long)req_offset(req));
1058
1059         if (status < 0) {
1060                 ClearPageUptodate(page);
1061                 SetPageError(page);
1062                 req->wb_context->error = status;
1063                 dprintk(", error = %d\n", status);
1064         } else {
1065 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1066                 if (data->verf.committed < NFS_FILE_SYNC) {
1067                         if (!NFS_NEED_COMMIT(req)) {
1068                                 nfs_defer_commit(req);
1069                                 memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1070                                 dprintk(" defer commit\n");
1071                         } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
1072                                 nfs_defer_reschedule(req);
1073                                 dprintk(" server reboot detected\n");
1074                         }
1075                 } else
1076 #endif
1077                         dprintk(" OK\n");
1078         }
1079
1080         if (atomic_dec_and_test(&req->wb_complete))
1081                 nfs_writepage_release(req);
1082 }
1083
1084 /*
1085  * Handle a write reply that flushes a whole page.
1086  *
1087  * FIXME: There is an inherent race with invalidate_inode_pages and
1088  *        writebacks since the page->count is kept > 1 for as long
1089  *        as the page has a write request pending.
1090  */
1091 static void nfs_writeback_done_full(struct nfs_write_data *data, int status)
1092 {
1093         struct nfs_page         *req;
1094         struct page             *page;
1095
1096         /* Update attributes as result of writeback. */
1097         while (!list_empty(&data->pages)) {
1098                 req = nfs_list_entry(data->pages.next);
1099                 nfs_list_remove_request(req);
1100                 page = req->wb_page;
1101
1102                 dprintk("NFS: write (%s/%Ld %d@%Ld)",
1103                         req->wb_context->dentry->d_inode->i_sb->s_id,
1104                         (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1105                         req->wb_bytes,
1106                         (long long)req_offset(req));
1107
1108                 if (status < 0) {
1109                         ClearPageUptodate(page);
1110                         SetPageError(page);
1111                         req->wb_context->error = status;
1112                         end_page_writeback(page);
1113                         nfs_inode_remove_request(req);
1114                         dprintk(", error = %d\n", status);
1115                         goto next;
1116                 }
1117                 end_page_writeback(page);
1118
1119 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1120                 if (data->args.stable != NFS_UNSTABLE || data->verf.committed == NFS_FILE_SYNC) {
1121                         nfs_inode_remove_request(req);
1122                         dprintk(" OK\n");
1123                         goto next;
1124                 }
1125                 memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1126                 nfs_mark_request_commit(req);
1127                 dprintk(" marked for commit\n");
1128 #else
1129                 nfs_inode_remove_request(req);
1130 #endif
1131         next:
1132                 nfs_clear_page_writeback(req);
1133         }
1134 }
1135
1136 /*
1137  * This function is called when the WRITE call is complete.
1138  */
1139 void nfs_writeback_done(struct rpc_task *task)
1140 {
1141         struct nfs_write_data   *data = (struct nfs_write_data *) task->tk_calldata;
1142         struct nfs_writeargs    *argp = &data->args;
1143         struct nfs_writeres     *resp = &data->res;
1144
1145         dprintk("NFS: %4d nfs_writeback_done (status %d)\n",
1146                 task->tk_pid, task->tk_status);
1147
1148 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1149         if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1150                 /* We tried a write call, but the server did not
1151                  * commit data to stable storage even though we
1152                  * requested it.
1153                  * Note: There is a known bug in Tru64 < 5.0 in which
1154                  *       the server reports NFS_DATA_SYNC, but performs
1155                  *       NFS_FILE_SYNC. We therefore implement this checking
1156                  *       as a dprintk() in order to avoid filling syslog.
1157                  */
1158                 static unsigned long    complain;
1159
1160                 if (time_before(complain, jiffies)) {
1161                         dprintk("NFS: faulty NFS server %s:"
1162                                 " (committed = %d) != (stable = %d)\n",
1163                                 NFS_SERVER(data->inode)->hostname,
1164                                 resp->verf->committed, argp->stable);
1165                         complain = jiffies + 300 * HZ;
1166                 }
1167         }
1168 #endif
1169         /* Is this a short write? */
1170         if (task->tk_status >= 0 && resp->count < argp->count) {
1171                 static unsigned long    complain;
1172
1173                 /* Has the server at least made some progress? */
1174                 if (resp->count != 0) {
1175                         /* Was this an NFSv2 write or an NFSv3 stable write? */
1176                         if (resp->verf->committed != NFS_UNSTABLE) {
1177                                 /* Resend from where the server left off */
1178                                 argp->offset += resp->count;
1179                                 argp->pgbase += resp->count;
1180                                 argp->count -= resp->count;
1181                         } else {
1182                                 /* Resend as a stable write in order to avoid
1183                                  * headaches in the case of a server crash.
1184                                  */
1185                                 argp->stable = NFS_FILE_SYNC;
1186                         }
1187                         rpc_restart_call(task);
1188                         return;
1189                 }
1190                 if (time_before(complain, jiffies)) {
1191                         printk(KERN_WARNING
1192                                "NFS: Server wrote zero bytes, expected %u.\n",
1193                                         argp->count);
1194                         complain = jiffies + 300 * HZ;
1195                 }
1196                 /* Can't do anything about it except throw an error. */
1197                 task->tk_status = -EIO;
1198         }
1199
1200         /*
1201          * Process the nfs_page list
1202          */
1203         data->complete(data, task->tk_status);
1204 }
1205
1206
1207 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1208 static void nfs_commit_release(struct rpc_task *task)
1209 {
1210         struct nfs_write_data   *wdata = (struct nfs_write_data *)task->tk_calldata;
1211         nfs_commit_free(wdata);
1212 }
1213
1214 /*
1215  * Set up the argument/result storage required for the RPC call.
1216  */
1217 static void nfs_commit_rpcsetup(struct list_head *head,
1218                 struct nfs_write_data *data, int how)
1219 {
1220         struct rpc_task         *task = &data->task;
1221         struct nfs_page         *first;
1222         struct inode            *inode;
1223
1224         /* Set up the RPC argument and reply structs
1225          * NB: take care not to mess about with data->commit et al. */
1226
1227         list_splice_init(head, &data->pages);
1228         first = nfs_list_entry(data->pages.next);
1229         inode = first->wb_context->dentry->d_inode;
1230
1231         data->inode       = inode;
1232         data->cred        = first->wb_context->cred;
1233
1234         data->args.fh     = NFS_FH(data->inode);
1235         /* Note: we always request a commit of the entire inode */
1236         data->args.offset = 0;
1237         data->args.count  = 0;
1238         data->res.count   = 0;
1239         data->res.fattr   = &data->fattr;
1240         data->res.verf    = &data->verf;
1241         nfs_fattr_init(&data->fattr);
1242         
1243         NFS_PROTO(inode)->commit_setup(data, how);
1244
1245         data->task.tk_priority = flush_task_priority(how);
1246         data->task.tk_cookie = (unsigned long)inode;
1247         data->task.tk_calldata = data;
1248         /* Release requests */
1249         data->task.tk_release = nfs_commit_release;
1250         
1251         dprintk("NFS: %4d initiated commit call\n", task->tk_pid);
1252 }
1253
1254 /*
1255  * Commit dirty pages
1256  */
1257 static int
1258 nfs_commit_list(struct list_head *head, int how)
1259 {
1260         struct nfs_write_data   *data;
1261         struct nfs_page         *req;
1262
1263         data = nfs_commit_alloc();
1264
1265         if (!data)
1266                 goto out_bad;
1267
1268         /* Set up the argument struct */
1269         nfs_commit_rpcsetup(head, data, how);
1270
1271         nfs_execute_write(data);
1272         return 0;
1273  out_bad:
1274         while (!list_empty(head)) {
1275                 req = nfs_list_entry(head->next);
1276                 nfs_list_remove_request(req);
1277                 nfs_mark_request_commit(req);
1278                 nfs_clear_page_writeback(req);
1279         }
1280         return -ENOMEM;
1281 }
1282
1283 /*
1284  * COMMIT call returned
1285  */
1286 void
1287 nfs_commit_done(struct rpc_task *task)
1288 {
1289         struct nfs_write_data   *data = (struct nfs_write_data *)task->tk_calldata;
1290         struct nfs_page         *req;
1291         int res = 0;
1292
1293         dprintk("NFS: %4d nfs_commit_done (status %d)\n",
1294                                 task->tk_pid, task->tk_status);
1295
1296         while (!list_empty(&data->pages)) {
1297                 req = nfs_list_entry(data->pages.next);
1298                 nfs_list_remove_request(req);
1299
1300                 dprintk("NFS: commit (%s/%Ld %d@%Ld)",
1301                         req->wb_context->dentry->d_inode->i_sb->s_id,
1302                         (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1303                         req->wb_bytes,
1304                         (long long)req_offset(req));
1305                 if (task->tk_status < 0) {
1306                         req->wb_context->error = task->tk_status;
1307                         nfs_inode_remove_request(req);
1308                         dprintk(", error = %d\n", task->tk_status);
1309                         goto next;
1310                 }
1311
1312                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1313                  * returned by the server against all stored verfs. */
1314                 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
1315                         /* We have a match */
1316                         nfs_inode_remove_request(req);
1317                         dprintk(" OK\n");
1318                         goto next;
1319                 }
1320                 /* We have a mismatch. Write the page again */
1321                 dprintk(" mismatch\n");
1322                 nfs_mark_request_dirty(req);
1323         next:
1324                 nfs_clear_page_writeback(req);
1325                 res++;
1326         }
1327         sub_page_state(nr_unstable,res);
1328 }
1329 #endif
1330
1331 static int nfs_flush_inode(struct inode *inode, unsigned long idx_start,
1332                            unsigned int npages, int how)
1333 {
1334         struct nfs_inode *nfsi = NFS_I(inode);
1335         LIST_HEAD(head);
1336         int                     res,
1337                                 error = 0;
1338
1339         spin_lock(&nfsi->req_lock);
1340         res = nfs_scan_dirty(inode, &head, idx_start, npages);
1341         spin_unlock(&nfsi->req_lock);
1342         if (res) {
1343                 struct nfs_server *server = NFS_SERVER(inode);
1344
1345                 /* For single writes, FLUSH_STABLE is more efficient */
1346                 if (res == nfsi->npages && nfsi->npages <= server->wpages) {
1347                         if (res > 1 || nfs_list_entry(head.next)->wb_bytes <= server->wsize)
1348                                 how |= FLUSH_STABLE;
1349                 }
1350                 error = nfs_flush_list(&head, server->wpages, how);
1351         }
1352         if (error < 0)
1353                 return error;
1354         return res;
1355 }
1356
1357 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1358 int nfs_commit_inode(struct inode *inode, int how)
1359 {
1360         struct nfs_inode *nfsi = NFS_I(inode);
1361         LIST_HEAD(head);
1362         int                     res,
1363                                 error = 0;
1364
1365         spin_lock(&nfsi->req_lock);
1366         res = nfs_scan_commit(inode, &head, 0, 0);
1367         spin_unlock(&nfsi->req_lock);
1368         if (res) {
1369                 error = nfs_commit_list(&head, how);
1370                 if (error < 0)
1371                         return error;
1372         }
1373         return res;
1374 }
1375 #endif
1376
1377 int nfs_sync_inode(struct inode *inode, unsigned long idx_start,
1378                   unsigned int npages, int how)
1379 {
1380         int     error,
1381                 wait;
1382
1383         wait = how & FLUSH_WAIT;
1384         how &= ~FLUSH_WAIT;
1385
1386         do {
1387                 error = 0;
1388                 if (wait)
1389                         error = nfs_wait_on_requests(inode, idx_start, npages);
1390                 if (error == 0)
1391                         error = nfs_flush_inode(inode, idx_start, npages, how);
1392 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1393                 if (error == 0)
1394                         error = nfs_commit_inode(inode, how);
1395 #endif
1396         } while (error > 0);
1397         return error;
1398 }
1399
1400 int nfs_init_writepagecache(void)
1401 {
1402         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1403                                              sizeof(struct nfs_write_data),
1404                                              0, SLAB_HWCACHE_ALIGN,
1405                                              NULL, NULL);
1406         if (nfs_wdata_cachep == NULL)
1407                 return -ENOMEM;
1408
1409         nfs_wdata_mempool = mempool_create(MIN_POOL_WRITE,
1410                                            mempool_alloc_slab,
1411                                            mempool_free_slab,
1412                                            nfs_wdata_cachep);
1413         if (nfs_wdata_mempool == NULL)
1414                 return -ENOMEM;
1415
1416         nfs_commit_mempool = mempool_create(MIN_POOL_COMMIT,
1417                                            mempool_alloc_slab,
1418                                            mempool_free_slab,
1419                                            nfs_wdata_cachep);
1420         if (nfs_commit_mempool == NULL)
1421                 return -ENOMEM;
1422
1423         return 0;
1424 }
1425
1426 void nfs_destroy_writepagecache(void)
1427 {
1428         mempool_destroy(nfs_commit_mempool);
1429         mempool_destroy(nfs_wdata_mempool);
1430         if (kmem_cache_destroy(nfs_wdata_cachep))
1431                 printk(KERN_INFO "nfs_write_data: not all structures were freed\n");
1432 }
1433