blob: 7e03eadb40c0a71d1dfd3971f8136abae2bb7822 [file] [log] [blame]
David Howells31143d52007-05-09 02:33:46 -07001/* handling of writes to regular files and writing back to the server
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
Alexey Dobriyan4af3c9c2007-10-16 23:29:23 -070011#include <linux/backing-dev.h>
David Howells31143d52007-05-09 02:33:46 -070012#include <linux/slab.h>
13#include <linux/fs.h>
14#include <linux/pagemap.h>
15#include <linux/writeback.h>
16#include <linux/pagevec.h>
17#include "internal.h"
18
19static int afs_write_back_from_locked_page(struct afs_writeback *wb,
20 struct page *page);
21
22/*
23 * mark a page as having been made dirty and thus needing writeback
24 */
25int afs_set_page_dirty(struct page *page)
26{
27 _enter("");
28 return __set_page_dirty_nobuffers(page);
29}
30
31/*
32 * unlink a writeback record because its usage has reached zero
33 * - must be called with the wb->vnode->writeback_lock held
34 */
35static void afs_unlink_writeback(struct afs_writeback *wb)
36{
37 struct afs_writeback *front;
38 struct afs_vnode *vnode = wb->vnode;
39
40 list_del_init(&wb->link);
41 if (!list_empty(&vnode->writebacks)) {
42 /* if an fsync rises to the front of the queue then wake it
43 * up */
44 front = list_entry(vnode->writebacks.next,
45 struct afs_writeback, link);
46 if (front->state == AFS_WBACK_SYNCING) {
47 _debug("wake up sync");
48 front->state = AFS_WBACK_COMPLETE;
49 wake_up(&front->waitq);
50 }
51 }
52}
53
54/*
55 * free a writeback record
56 */
57static void afs_free_writeback(struct afs_writeback *wb)
58{
59 _enter("");
60 key_put(wb->key);
61 kfree(wb);
62}
63
64/*
65 * dispose of a reference to a writeback record
66 */
67void afs_put_writeback(struct afs_writeback *wb)
68{
69 struct afs_vnode *vnode = wb->vnode;
70
71 _enter("{%d}", wb->usage);
72
73 spin_lock(&vnode->writeback_lock);
74 if (--wb->usage == 0)
75 afs_unlink_writeback(wb);
76 else
77 wb = NULL;
78 spin_unlock(&vnode->writeback_lock);
79 if (wb)
80 afs_free_writeback(wb);
81}
82
83/*
84 * partly or wholly fill a page that's under preparation for writing
85 */
86static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
Anton Blanchard5e7f2332011-06-13 22:31:12 +010087 loff_t pos, struct page *page)
David Howells31143d52007-05-09 02:33:46 -070088{
Nick Piggin15b46502008-10-15 22:04:32 -070089 loff_t i_size;
David Howells31143d52007-05-09 02:33:46 -070090 int ret;
Anton Blanchard5e7f2332011-06-13 22:31:12 +010091 int len;
David Howells31143d52007-05-09 02:33:46 -070092
Anton Blanchard5e7f2332011-06-13 22:31:12 +010093 _enter(",,%llu", (unsigned long long)pos);
David Howells31143d52007-05-09 02:33:46 -070094
Nick Piggin15b46502008-10-15 22:04:32 -070095 i_size = i_size_read(&vnode->vfs_inode);
Anton Blanchard5e7f2332011-06-13 22:31:12 +010096 if (pos + PAGE_CACHE_SIZE > i_size)
97 len = i_size - pos;
Nick Piggin15b46502008-10-15 22:04:32 -070098 else
Anton Blanchard5e7f2332011-06-13 22:31:12 +010099 len = PAGE_CACHE_SIZE;
Nick Piggin15b46502008-10-15 22:04:32 -0700100
Anton Blanchard5e7f2332011-06-13 22:31:12 +0100101 ret = afs_vnode_fetch_data(vnode, key, pos, len, page);
David Howells31143d52007-05-09 02:33:46 -0700102 if (ret < 0) {
103 if (ret == -ENOENT) {
104 _debug("got NOENT from server"
105 " - marking file deleted and stale");
106 set_bit(AFS_VNODE_DELETED, &vnode->flags);
107 ret = -ESTALE;
108 }
109 }
110
111 _leave(" = %d", ret);
112 return ret;
113}
114
115/*
David Howells31143d52007-05-09 02:33:46 -0700116 * prepare to perform part of a write to a page
David Howells31143d52007-05-09 02:33:46 -0700117 */
Nick Piggin15b46502008-10-15 22:04:32 -0700118int afs_write_begin(struct file *file, struct address_space *mapping,
119 loff_t pos, unsigned len, unsigned flags,
120 struct page **pagep, void **fsdata)
David Howells31143d52007-05-09 02:33:46 -0700121{
122 struct afs_writeback *candidate, *wb;
Al Viro496ad9a2013-01-23 17:07:38 -0500123 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
Nick Piggin15b46502008-10-15 22:04:32 -0700124 struct page *page;
David Howells31143d52007-05-09 02:33:46 -0700125 struct key *key = file->private_data;
Nick Piggin15b46502008-10-15 22:04:32 -0700126 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
127 unsigned to = from + len;
128 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
David Howells31143d52007-05-09 02:33:46 -0700129 int ret;
130
131 _enter("{%x:%u},{%lx},%u,%u",
Nick Piggin15b46502008-10-15 22:04:32 -0700132 vnode->fid.vid, vnode->fid.vnode, index, from, to);
David Howells31143d52007-05-09 02:33:46 -0700133
134 candidate = kzalloc(sizeof(*candidate), GFP_KERNEL);
135 if (!candidate)
136 return -ENOMEM;
137 candidate->vnode = vnode;
Nick Piggin15b46502008-10-15 22:04:32 -0700138 candidate->first = candidate->last = index;
139 candidate->offset_first = from;
David Howells31143d52007-05-09 02:33:46 -0700140 candidate->to_last = to;
Anton Blanchardf129ccc2011-02-25 15:33:02 +0000141 INIT_LIST_HEAD(&candidate->link);
David Howells31143d52007-05-09 02:33:46 -0700142 candidate->usage = 1;
143 candidate->state = AFS_WBACK_PENDING;
144 init_waitqueue_head(&candidate->waitq);
145
Nick Piggin54566b22009-01-04 12:00:53 -0800146 page = grab_cache_page_write_begin(mapping, index, flags);
Nick Piggin15b46502008-10-15 22:04:32 -0700147 if (!page) {
148 kfree(candidate);
149 return -ENOMEM;
150 }
151 *pagep = page;
152 /* page won't leak in error case: it eventually gets cleaned off LRU */
153
Anton Blanchard5e7f2332011-06-13 22:31:12 +0100154 if (!PageUptodate(page) && len != PAGE_CACHE_SIZE) {
155 ret = afs_fill_page(vnode, key, index << PAGE_CACHE_SHIFT, page);
David Howells31143d52007-05-09 02:33:46 -0700156 if (ret < 0) {
157 kfree(candidate);
158 _leave(" = %d [prep]", ret);
159 return ret;
160 }
Nick Piggin15b46502008-10-15 22:04:32 -0700161 SetPageUptodate(page);
David Howells31143d52007-05-09 02:33:46 -0700162 }
163
164try_again:
David Howells31143d52007-05-09 02:33:46 -0700165 spin_lock(&vnode->writeback_lock);
166
167 /* see if this page is already pending a writeback under a suitable key
168 * - if so we can just join onto that one */
169 wb = (struct afs_writeback *) page_private(page);
170 if (wb) {
171 if (wb->key == key && wb->state == AFS_WBACK_PENDING)
172 goto subsume_in_current_wb;
173 goto flush_conflicting_wb;
174 }
175
176 if (index > 0) {
177 /* see if we can find an already pending writeback that we can
178 * append this page to */
179 list_for_each_entry(wb, &vnode->writebacks, link) {
180 if (wb->last == index - 1 && wb->key == key &&
181 wb->state == AFS_WBACK_PENDING)
182 goto append_to_previous_wb;
183 }
184 }
185
186 list_add_tail(&candidate->link, &vnode->writebacks);
187 candidate->key = key_get(key);
188 spin_unlock(&vnode->writeback_lock);
189 SetPagePrivate(page);
190 set_page_private(page, (unsigned long) candidate);
191 _leave(" = 0 [new]");
192 return 0;
193
194subsume_in_current_wb:
195 _debug("subsume");
196 ASSERTRANGE(wb->first, <=, index, <=, wb->last);
Nick Piggin15b46502008-10-15 22:04:32 -0700197 if (index == wb->first && from < wb->offset_first)
198 wb->offset_first = from;
David Howells31143d52007-05-09 02:33:46 -0700199 if (index == wb->last && to > wb->to_last)
200 wb->to_last = to;
201 spin_unlock(&vnode->writeback_lock);
202 kfree(candidate);
203 _leave(" = 0 [sub]");
204 return 0;
205
206append_to_previous_wb:
207 _debug("append into %lx-%lx", wb->first, wb->last);
208 wb->usage++;
209 wb->last++;
210 wb->to_last = to;
211 spin_unlock(&vnode->writeback_lock);
212 SetPagePrivate(page);
213 set_page_private(page, (unsigned long) wb);
214 kfree(candidate);
215 _leave(" = 0 [app]");
216 return 0;
217
218 /* the page is currently bound to another context, so if it's dirty we
219 * need to flush it before we can use the new context */
220flush_conflicting_wb:
221 _debug("flush conflict");
222 if (wb->state == AFS_WBACK_PENDING)
223 wb->state = AFS_WBACK_CONFLICTING;
224 spin_unlock(&vnode->writeback_lock);
225 if (PageDirty(page)) {
226 ret = afs_write_back_from_locked_page(wb, page);
227 if (ret < 0) {
228 afs_put_writeback(candidate);
229 _leave(" = %d", ret);
230 return ret;
231 }
232 }
233
234 /* the page holds a ref on the writeback record */
235 afs_put_writeback(wb);
236 set_page_private(page, 0);
237 ClearPagePrivate(page);
238 goto try_again;
239}
240
241/*
242 * finalise part of a write to a page
243 */
Nick Piggin15b46502008-10-15 22:04:32 -0700244int afs_write_end(struct file *file, struct address_space *mapping,
245 loff_t pos, unsigned len, unsigned copied,
246 struct page *page, void *fsdata)
David Howells31143d52007-05-09 02:33:46 -0700247{
Al Viro496ad9a2013-01-23 17:07:38 -0500248 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
David Howells31143d52007-05-09 02:33:46 -0700249 loff_t i_size, maybe_i_size;
250
Nick Piggin15b46502008-10-15 22:04:32 -0700251 _enter("{%x:%u},{%lx}",
252 vnode->fid.vid, vnode->fid.vnode, page->index);
David Howells31143d52007-05-09 02:33:46 -0700253
Nick Piggin15b46502008-10-15 22:04:32 -0700254 maybe_i_size = pos + copied;
David Howells31143d52007-05-09 02:33:46 -0700255
256 i_size = i_size_read(&vnode->vfs_inode);
257 if (maybe_i_size > i_size) {
258 spin_lock(&vnode->writeback_lock);
259 i_size = i_size_read(&vnode->vfs_inode);
260 if (maybe_i_size > i_size)
261 i_size_write(&vnode->vfs_inode, maybe_i_size);
262 spin_unlock(&vnode->writeback_lock);
263 }
264
265 set_page_dirty(page);
David Howells31143d52007-05-09 02:33:46 -0700266 if (PageDirty(page))
267 _debug("dirtied");
Nick Piggin15b46502008-10-15 22:04:32 -0700268 unlock_page(page);
269 page_cache_release(page);
David Howells31143d52007-05-09 02:33:46 -0700270
Nick Piggin15b46502008-10-15 22:04:32 -0700271 return copied;
David Howells31143d52007-05-09 02:33:46 -0700272}
273
274/*
275 * kill all the pages in the given range
276 */
277static void afs_kill_pages(struct afs_vnode *vnode, bool error,
278 pgoff_t first, pgoff_t last)
279{
280 struct pagevec pv;
281 unsigned count, loop;
282
283 _enter("{%x:%u},%lx-%lx",
284 vnode->fid.vid, vnode->fid.vnode, first, last);
285
286 pagevec_init(&pv, 0);
287
288 do {
289 _debug("kill %lx-%lx", first, last);
290
291 count = last - first + 1;
292 if (count > PAGEVEC_SIZE)
293 count = PAGEVEC_SIZE;
294 pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping,
295 first, count, pv.pages);
296 ASSERTCMP(pv.nr, ==, count);
297
298 for (loop = 0; loop < count; loop++) {
299 ClearPageUptodate(pv.pages[loop]);
300 if (error)
301 SetPageError(pv.pages[loop]);
302 end_page_writeback(pv.pages[loop]);
303 }
304
305 __pagevec_release(&pv);
306 } while (first < last);
307
308 _leave("");
309}
310
311/*
312 * synchronously write back the locked page and any subsequent non-locked dirty
313 * pages also covered by the same writeback record
314 */
315static int afs_write_back_from_locked_page(struct afs_writeback *wb,
316 struct page *primary_page)
317{
318 struct page *pages[8], *page;
319 unsigned long count;
320 unsigned n, offset, to;
321 pgoff_t start, first, last;
322 int loop, ret;
323
324 _enter(",%lx", primary_page->index);
325
326 count = 1;
327 if (!clear_page_dirty_for_io(primary_page))
328 BUG();
329 if (test_set_page_writeback(primary_page))
330 BUG();
331
332 /* find all consecutive lockable dirty pages, stopping when we find a
333 * page that is not immediately lockable, is not dirty or is missing,
334 * or we reach the end of the range */
335 start = primary_page->index;
336 if (start >= wb->last)
337 goto no_more;
338 start++;
339 do {
340 _debug("more %lx [%lx]", start, count);
341 n = wb->last - start + 1;
342 if (n > ARRAY_SIZE(pages))
343 n = ARRAY_SIZE(pages);
344 n = find_get_pages_contig(wb->vnode->vfs_inode.i_mapping,
345 start, n, pages);
346 _debug("fgpc %u", n);
347 if (n == 0)
348 goto no_more;
349 if (pages[0]->index != start) {
David Howells9d577b62007-05-10 22:22:19 -0700350 do {
351 put_page(pages[--n]);
352 } while (n > 0);
David Howells31143d52007-05-09 02:33:46 -0700353 goto no_more;
354 }
355
356 for (loop = 0; loop < n; loop++) {
357 page = pages[loop];
358 if (page->index > wb->last)
359 break;
Nick Piggin529ae9a2008-08-02 12:01:03 +0200360 if (!trylock_page(page))
David Howells31143d52007-05-09 02:33:46 -0700361 break;
362 if (!PageDirty(page) ||
363 page_private(page) != (unsigned long) wb) {
364 unlock_page(page);
365 break;
366 }
367 if (!clear_page_dirty_for_io(page))
368 BUG();
369 if (test_set_page_writeback(page))
370 BUG();
371 unlock_page(page);
372 put_page(page);
373 }
374 count += loop;
375 if (loop < n) {
376 for (; loop < n; loop++)
377 put_page(pages[loop]);
378 goto no_more;
379 }
380
381 start += loop;
382 } while (start <= wb->last && count < 65536);
383
384no_more:
385 /* we now have a contiguous set of dirty pages, each with writeback set
386 * and the dirty mark cleared; the first page is locked and must remain
387 * so, all the rest are unlocked */
388 first = primary_page->index;
389 last = first + count - 1;
390
391 offset = (first == wb->first) ? wb->offset_first : 0;
392 to = (last == wb->last) ? wb->to_last : PAGE_SIZE;
393
394 _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to);
395
396 ret = afs_vnode_store_data(wb, first, last, offset, to);
397 if (ret < 0) {
398 switch (ret) {
399 case -EDQUOT:
400 case -ENOSPC:
401 set_bit(AS_ENOSPC,
402 &wb->vnode->vfs_inode.i_mapping->flags);
403 break;
404 case -EROFS:
405 case -EIO:
406 case -EREMOTEIO:
407 case -EFBIG:
408 case -ENOENT:
409 case -ENOMEDIUM:
410 case -ENXIO:
411 afs_kill_pages(wb->vnode, true, first, last);
412 set_bit(AS_EIO, &wb->vnode->vfs_inode.i_mapping->flags);
413 break;
414 case -EACCES:
415 case -EPERM:
416 case -ENOKEY:
417 case -EKEYEXPIRED:
418 case -EKEYREJECTED:
419 case -EKEYREVOKED:
420 afs_kill_pages(wb->vnode, false, first, last);
421 break;
422 default:
423 break;
424 }
425 } else {
426 ret = count;
427 }
428
429 _leave(" = %d", ret);
430 return ret;
431}
432
433/*
434 * write a page back to the server
435 * - the caller locked the page for us
436 */
437int afs_writepage(struct page *page, struct writeback_control *wbc)
438{
David Howells31143d52007-05-09 02:33:46 -0700439 struct afs_writeback *wb;
440 int ret;
441
442 _enter("{%lx},", page->index);
443
David Howells31143d52007-05-09 02:33:46 -0700444 wb = (struct afs_writeback *) page_private(page);
445 ASSERT(wb != NULL);
446
447 ret = afs_write_back_from_locked_page(wb, page);
448 unlock_page(page);
449 if (ret < 0) {
450 _leave(" = %d", ret);
451 return 0;
452 }
453
454 wbc->nr_to_write -= ret;
David Howells31143d52007-05-09 02:33:46 -0700455
456 _leave(" = 0");
457 return 0;
458}
459
460/*
461 * write a region of pages back to the server
462 */
Adrian Bunkc1206a22007-10-16 23:26:41 -0700463static int afs_writepages_region(struct address_space *mapping,
464 struct writeback_control *wbc,
465 pgoff_t index, pgoff_t end, pgoff_t *_next)
David Howells31143d52007-05-09 02:33:46 -0700466{
David Howells31143d52007-05-09 02:33:46 -0700467 struct afs_writeback *wb;
468 struct page *page;
469 int ret, n;
470
471 _enter(",,%lx,%lx,", index, end);
472
473 do {
474 n = find_get_pages_tag(mapping, &index, PAGECACHE_TAG_DIRTY,
475 1, &page);
476 if (!n)
477 break;
478
479 _debug("wback %lx", page->index);
480
481 if (page->index > end) {
482 *_next = index;
483 page_cache_release(page);
484 _leave(" = 0 [%lx]", *_next);
485 return 0;
486 }
487
488 /* at this point we hold neither mapping->tree_lock nor lock on
489 * the page itself: the page may be truncated or invalidated
490 * (changing page->mapping to NULL), or even swizzled back from
491 * swapper_space to tmpfs file mapping
492 */
493 lock_page(page);
494
495 if (page->mapping != mapping) {
496 unlock_page(page);
497 page_cache_release(page);
498 continue;
499 }
500
501 if (wbc->sync_mode != WB_SYNC_NONE)
502 wait_on_page_writeback(page);
503
504 if (PageWriteback(page) || !PageDirty(page)) {
505 unlock_page(page);
506 continue;
507 }
508
509 wb = (struct afs_writeback *) page_private(page);
510 ASSERT(wb != NULL);
511
512 spin_lock(&wb->vnode->writeback_lock);
513 wb->state = AFS_WBACK_WRITING;
514 spin_unlock(&wb->vnode->writeback_lock);
515
516 ret = afs_write_back_from_locked_page(wb, page);
517 unlock_page(page);
518 page_cache_release(page);
519 if (ret < 0) {
520 _leave(" = %d", ret);
521 return ret;
522 }
523
524 wbc->nr_to_write -= ret;
525
David Howells31143d52007-05-09 02:33:46 -0700526 cond_resched();
527 } while (index < end && wbc->nr_to_write > 0);
528
529 *_next = index;
530 _leave(" = 0 [%lx]", *_next);
531 return 0;
532}
533
534/*
535 * write some of the pending data back to the server
536 */
537int afs_writepages(struct address_space *mapping,
538 struct writeback_control *wbc)
539{
David Howells31143d52007-05-09 02:33:46 -0700540 pgoff_t start, end, next;
541 int ret;
542
543 _enter("");
544
David Howells31143d52007-05-09 02:33:46 -0700545 if (wbc->range_cyclic) {
546 start = mapping->writeback_index;
547 end = -1;
548 ret = afs_writepages_region(mapping, wbc, start, end, &next);
Wu Fengguang1b430be2010-10-26 14:21:26 -0700549 if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
David Howells31143d52007-05-09 02:33:46 -0700550 ret = afs_writepages_region(mapping, wbc, 0, start,
551 &next);
552 mapping->writeback_index = next;
553 } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
554 end = (pgoff_t)(LLONG_MAX >> PAGE_CACHE_SHIFT);
555 ret = afs_writepages_region(mapping, wbc, 0, end, &next);
556 if (wbc->nr_to_write > 0)
557 mapping->writeback_index = next;
558 } else {
559 start = wbc->range_start >> PAGE_CACHE_SHIFT;
560 end = wbc->range_end >> PAGE_CACHE_SHIFT;
561 ret = afs_writepages_region(mapping, wbc, start, end, &next);
562 }
563
564 _leave(" = %d", ret);
565 return ret;
566}
567
568/*
David Howells31143d52007-05-09 02:33:46 -0700569 * completion of write to server
570 */
571void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call)
572{
573 struct afs_writeback *wb = call->wb;
574 struct pagevec pv;
575 unsigned count, loop;
576 pgoff_t first = call->first, last = call->last;
577 bool free_wb;
578
579 _enter("{%x:%u},{%lx-%lx}",
580 vnode->fid.vid, vnode->fid.vnode, first, last);
581
582 ASSERT(wb != NULL);
583
584 pagevec_init(&pv, 0);
585
586 do {
David Howells5bbf5d32007-05-10 03:15:23 -0700587 _debug("done %lx-%lx", first, last);
David Howells31143d52007-05-09 02:33:46 -0700588
589 count = last - first + 1;
590 if (count > PAGEVEC_SIZE)
591 count = PAGEVEC_SIZE;
592 pv.nr = find_get_pages_contig(call->mapping, first, count,
593 pv.pages);
594 ASSERTCMP(pv.nr, ==, count);
595
596 spin_lock(&vnode->writeback_lock);
597 for (loop = 0; loop < count; loop++) {
598 struct page *page = pv.pages[loop];
599 end_page_writeback(page);
600 if (page_private(page) == (unsigned long) wb) {
601 set_page_private(page, 0);
602 ClearPagePrivate(page);
603 wb->usage--;
604 }
605 }
606 free_wb = false;
607 if (wb->usage == 0) {
608 afs_unlink_writeback(wb);
609 free_wb = true;
610 }
611 spin_unlock(&vnode->writeback_lock);
612 first += count;
613 if (free_wb) {
614 afs_free_writeback(wb);
615 wb = NULL;
616 }
617
618 __pagevec_release(&pv);
David Howells5bbf5d32007-05-10 03:15:23 -0700619 } while (first <= last);
David Howells31143d52007-05-09 02:33:46 -0700620
621 _leave("");
622}
623
624/*
625 * write to an AFS file
626 */
627ssize_t afs_file_write(struct kiocb *iocb, const struct iovec *iov,
628 unsigned long nr_segs, loff_t pos)
629{
Al Viro496ad9a2013-01-23 17:07:38 -0500630 struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp));
David Howells31143d52007-05-09 02:33:46 -0700631 ssize_t result;
632 size_t count = iov_length(iov, nr_segs);
David Howells31143d52007-05-09 02:33:46 -0700633
634 _enter("{%x.%u},{%zu},%lu,",
635 vnode->fid.vid, vnode->fid.vnode, count, nr_segs);
636
637 if (IS_SWAPFILE(&vnode->vfs_inode)) {
638 printk(KERN_INFO
639 "AFS: Attempt to write to active swap file!\n");
640 return -EBUSY;
641 }
642
643 if (!count)
644 return 0;
645
646 result = generic_file_aio_write(iocb, iov, nr_segs, pos);
647 if (IS_ERR_VALUE(result)) {
648 _leave(" = %zd", result);
649 return result;
650 }
651
David Howells31143d52007-05-09 02:33:46 -0700652 _leave(" = %zd", result);
653 return result;
654}
655
656/*
657 * flush the vnode to the fileserver
658 */
659int afs_writeback_all(struct afs_vnode *vnode)
660{
661 struct address_space *mapping = vnode->vfs_inode.i_mapping;
662 struct writeback_control wbc = {
David Howells31143d52007-05-09 02:33:46 -0700663 .sync_mode = WB_SYNC_ALL,
664 .nr_to_write = LONG_MAX,
David Howells31143d52007-05-09 02:33:46 -0700665 .range_cyclic = 1,
666 };
667 int ret;
668
669 _enter("");
670
671 ret = mapping->a_ops->writepages(mapping, &wbc);
672 __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
673
674 _leave(" = %d", ret);
675 return ret;
676}
677
678/*
679 * flush any dirty pages for this process, and check for write errors.
680 * - the return status from this call provides a reliable indication of
681 * whether any write errors occurred for this process.
682 */
Josef Bacik02c24a82011-07-16 20:44:56 -0400683int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
David Howells31143d52007-05-09 02:33:46 -0700684{
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200685 struct dentry *dentry = file->f_path.dentry;
Josef Bacik02c24a82011-07-16 20:44:56 -0400686 struct inode *inode = file->f_mapping->host;
David Howells31143d52007-05-09 02:33:46 -0700687 struct afs_writeback *wb, *xwb;
688 struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
689 int ret;
690
691 _enter("{%x:%u},{n=%s},%d",
692 vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
693 datasync);
694
Josef Bacik02c24a82011-07-16 20:44:56 -0400695 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
696 if (ret)
697 return ret;
698 mutex_lock(&inode->i_mutex);
699
David Howells31143d52007-05-09 02:33:46 -0700700 /* use a writeback record as a marker in the queue - when this reaches
701 * the front of the queue, all the outstanding writes are either
702 * completed or rejected */
703 wb = kzalloc(sizeof(*wb), GFP_KERNEL);
Josef Bacik02c24a82011-07-16 20:44:56 -0400704 if (!wb) {
705 ret = -ENOMEM;
706 goto out;
707 }
David Howells31143d52007-05-09 02:33:46 -0700708 wb->vnode = vnode;
709 wb->first = 0;
710 wb->last = -1;
711 wb->offset_first = 0;
712 wb->to_last = PAGE_SIZE;
713 wb->usage = 1;
714 wb->state = AFS_WBACK_SYNCING;
715 init_waitqueue_head(&wb->waitq);
716
717 spin_lock(&vnode->writeback_lock);
718 list_for_each_entry(xwb, &vnode->writebacks, link) {
719 if (xwb->state == AFS_WBACK_PENDING)
720 xwb->state = AFS_WBACK_CONFLICTING;
721 }
722 list_add_tail(&wb->link, &vnode->writebacks);
723 spin_unlock(&vnode->writeback_lock);
724
725 /* push all the outstanding writebacks to the server */
726 ret = afs_writeback_all(vnode);
727 if (ret < 0) {
728 afs_put_writeback(wb);
729 _leave(" = %d [wb]", ret);
Josef Bacik02c24a82011-07-16 20:44:56 -0400730 goto out;
David Howells31143d52007-05-09 02:33:46 -0700731 }
732
733 /* wait for the preceding writes to actually complete */
734 ret = wait_event_interruptible(wb->waitq,
735 wb->state == AFS_WBACK_COMPLETE ||
736 vnode->writebacks.next == &wb->link);
737 afs_put_writeback(wb);
738 _leave(" = %d", ret);
Josef Bacik02c24a82011-07-16 20:44:56 -0400739out:
740 mutex_unlock(&inode->i_mutex);
David Howells31143d52007-05-09 02:33:46 -0700741 return ret;
742}
David Howells9b3f26c2009-04-03 16:42:41 +0100743
744/*
745 * notification that a previously read-only page is about to become writable
746 * - if it returns an error, the caller will deliver a bus error signal
747 */
748int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
749{
750 struct afs_vnode *vnode = AFS_FS_I(vma->vm_file->f_mapping->host);
751
752 _enter("{{%x:%u}},{%lx}",
753 vnode->fid.vid, vnode->fid.vnode, page->index);
754
755 /* wait for the page to be written to the cache before we allow it to
756 * be modified */
757#ifdef CONFIG_AFS_FSCACHE
758 fscache_wait_on_page_write(vnode->cache, page);
759#endif
760
761 _leave(" = 0");
762 return 0;
763}