blob: ab6adfd525168800524349791c061512a47a7d81 [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>
Kent Overstreeta27bb332013-05-07 16:19:08 -070017#include <linux/aio.h>
David Howells31143d52007-05-09 02:33:46 -070018#include "internal.h"
19
20static int afs_write_back_from_locked_page(struct afs_writeback *wb,
21 struct page *page);
22
23/*
24 * mark a page as having been made dirty and thus needing writeback
25 */
26int afs_set_page_dirty(struct page *page)
27{
28 _enter("");
29 return __set_page_dirty_nobuffers(page);
30}
31
32/*
33 * unlink a writeback record because its usage has reached zero
34 * - must be called with the wb->vnode->writeback_lock held
35 */
36static void afs_unlink_writeback(struct afs_writeback *wb)
37{
38 struct afs_writeback *front;
39 struct afs_vnode *vnode = wb->vnode;
40
41 list_del_init(&wb->link);
42 if (!list_empty(&vnode->writebacks)) {
43 /* if an fsync rises to the front of the queue then wake it
44 * up */
45 front = list_entry(vnode->writebacks.next,
46 struct afs_writeback, link);
47 if (front->state == AFS_WBACK_SYNCING) {
48 _debug("wake up sync");
49 front->state = AFS_WBACK_COMPLETE;
50 wake_up(&front->waitq);
51 }
52 }
53}
54
55/*
56 * free a writeback record
57 */
58static void afs_free_writeback(struct afs_writeback *wb)
59{
60 _enter("");
61 key_put(wb->key);
62 kfree(wb);
63}
64
65/*
66 * dispose of a reference to a writeback record
67 */
68void afs_put_writeback(struct afs_writeback *wb)
69{
70 struct afs_vnode *vnode = wb->vnode;
71
72 _enter("{%d}", wb->usage);
73
74 spin_lock(&vnode->writeback_lock);
75 if (--wb->usage == 0)
76 afs_unlink_writeback(wb);
77 else
78 wb = NULL;
79 spin_unlock(&vnode->writeback_lock);
80 if (wb)
81 afs_free_writeback(wb);
82}
83
84/*
85 * partly or wholly fill a page that's under preparation for writing
86 */
87static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
Anton Blanchard5e7f2332011-06-13 22:31:12 +010088 loff_t pos, struct page *page)
David Howells31143d52007-05-09 02:33:46 -070089{
Nick Piggin15b46502008-10-15 22:04:32 -070090 loff_t i_size;
David Howells31143d52007-05-09 02:33:46 -070091 int ret;
Anton Blanchard5e7f2332011-06-13 22:31:12 +010092 int len;
David Howells31143d52007-05-09 02:33:46 -070093
Anton Blanchard5e7f2332011-06-13 22:31:12 +010094 _enter(",,%llu", (unsigned long long)pos);
David Howells31143d52007-05-09 02:33:46 -070095
Nick Piggin15b46502008-10-15 22:04:32 -070096 i_size = i_size_read(&vnode->vfs_inode);
Anton Blanchard5e7f2332011-06-13 22:31:12 +010097 if (pos + PAGE_CACHE_SIZE > i_size)
98 len = i_size - pos;
Nick Piggin15b46502008-10-15 22:04:32 -070099 else
Anton Blanchard5e7f2332011-06-13 22:31:12 +0100100 len = PAGE_CACHE_SIZE;
Nick Piggin15b46502008-10-15 22:04:32 -0700101
Anton Blanchard5e7f2332011-06-13 22:31:12 +0100102 ret = afs_vnode_fetch_data(vnode, key, pos, len, page);
David Howells31143d52007-05-09 02:33:46 -0700103 if (ret < 0) {
104 if (ret == -ENOENT) {
105 _debug("got NOENT from server"
106 " - marking file deleted and stale");
107 set_bit(AFS_VNODE_DELETED, &vnode->flags);
108 ret = -ESTALE;
109 }
110 }
111
112 _leave(" = %d", ret);
113 return ret;
114}
115
116/*
David Howells31143d52007-05-09 02:33:46 -0700117 * prepare to perform part of a write to a page
David Howells31143d52007-05-09 02:33:46 -0700118 */
Nick Piggin15b46502008-10-15 22:04:32 -0700119int afs_write_begin(struct file *file, struct address_space *mapping,
120 loff_t pos, unsigned len, unsigned flags,
121 struct page **pagep, void **fsdata)
David Howells31143d52007-05-09 02:33:46 -0700122{
123 struct afs_writeback *candidate, *wb;
Al Viro496ad9a2013-01-23 17:07:38 -0500124 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
Nick Piggin15b46502008-10-15 22:04:32 -0700125 struct page *page;
David Howells31143d52007-05-09 02:33:46 -0700126 struct key *key = file->private_data;
Nick Piggin15b46502008-10-15 22:04:32 -0700127 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
128 unsigned to = from + len;
129 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
David Howells31143d52007-05-09 02:33:46 -0700130 int ret;
131
132 _enter("{%x:%u},{%lx},%u,%u",
Nick Piggin15b46502008-10-15 22:04:32 -0700133 vnode->fid.vid, vnode->fid.vnode, index, from, to);
David Howells31143d52007-05-09 02:33:46 -0700134
135 candidate = kzalloc(sizeof(*candidate), GFP_KERNEL);
136 if (!candidate)
137 return -ENOMEM;
138 candidate->vnode = vnode;
Nick Piggin15b46502008-10-15 22:04:32 -0700139 candidate->first = candidate->last = index;
140 candidate->offset_first = from;
David Howells31143d52007-05-09 02:33:46 -0700141 candidate->to_last = to;
Anton Blanchardf129ccc2011-02-25 15:33:02 +0000142 INIT_LIST_HEAD(&candidate->link);
David Howells31143d52007-05-09 02:33:46 -0700143 candidate->usage = 1;
144 candidate->state = AFS_WBACK_PENDING;
145 init_waitqueue_head(&candidate->waitq);
146
Nick Piggin54566b22009-01-04 12:00:53 -0800147 page = grab_cache_page_write_begin(mapping, index, flags);
Nick Piggin15b46502008-10-15 22:04:32 -0700148 if (!page) {
149 kfree(candidate);
150 return -ENOMEM;
151 }
152 *pagep = page;
153 /* page won't leak in error case: it eventually gets cleaned off LRU */
154
Anton Blanchard5e7f2332011-06-13 22:31:12 +0100155 if (!PageUptodate(page) && len != PAGE_CACHE_SIZE) {
156 ret = afs_fill_page(vnode, key, index << PAGE_CACHE_SHIFT, page);
David Howells31143d52007-05-09 02:33:46 -0700157 if (ret < 0) {
158 kfree(candidate);
159 _leave(" = %d [prep]", ret);
160 return ret;
161 }
Nick Piggin15b46502008-10-15 22:04:32 -0700162 SetPageUptodate(page);
David Howells31143d52007-05-09 02:33:46 -0700163 }
164
165try_again:
David Howells31143d52007-05-09 02:33:46 -0700166 spin_lock(&vnode->writeback_lock);
167
168 /* see if this page is already pending a writeback under a suitable key
169 * - if so we can just join onto that one */
170 wb = (struct afs_writeback *) page_private(page);
171 if (wb) {
172 if (wb->key == key && wb->state == AFS_WBACK_PENDING)
173 goto subsume_in_current_wb;
174 goto flush_conflicting_wb;
175 }
176
177 if (index > 0) {
178 /* see if we can find an already pending writeback that we can
179 * append this page to */
180 list_for_each_entry(wb, &vnode->writebacks, link) {
181 if (wb->last == index - 1 && wb->key == key &&
182 wb->state == AFS_WBACK_PENDING)
183 goto append_to_previous_wb;
184 }
185 }
186
187 list_add_tail(&candidate->link, &vnode->writebacks);
188 candidate->key = key_get(key);
189 spin_unlock(&vnode->writeback_lock);
190 SetPagePrivate(page);
191 set_page_private(page, (unsigned long) candidate);
192 _leave(" = 0 [new]");
193 return 0;
194
195subsume_in_current_wb:
196 _debug("subsume");
197 ASSERTRANGE(wb->first, <=, index, <=, wb->last);
Nick Piggin15b46502008-10-15 22:04:32 -0700198 if (index == wb->first && from < wb->offset_first)
199 wb->offset_first = from;
David Howells31143d52007-05-09 02:33:46 -0700200 if (index == wb->last && to > wb->to_last)
201 wb->to_last = to;
202 spin_unlock(&vnode->writeback_lock);
203 kfree(candidate);
204 _leave(" = 0 [sub]");
205 return 0;
206
207append_to_previous_wb:
208 _debug("append into %lx-%lx", wb->first, wb->last);
209 wb->usage++;
210 wb->last++;
211 wb->to_last = to;
212 spin_unlock(&vnode->writeback_lock);
213 SetPagePrivate(page);
214 set_page_private(page, (unsigned long) wb);
215 kfree(candidate);
216 _leave(" = 0 [app]");
217 return 0;
218
219 /* the page is currently bound to another context, so if it's dirty we
220 * need to flush it before we can use the new context */
221flush_conflicting_wb:
222 _debug("flush conflict");
223 if (wb->state == AFS_WBACK_PENDING)
224 wb->state = AFS_WBACK_CONFLICTING;
225 spin_unlock(&vnode->writeback_lock);
226 if (PageDirty(page)) {
227 ret = afs_write_back_from_locked_page(wb, page);
228 if (ret < 0) {
229 afs_put_writeback(candidate);
230 _leave(" = %d", ret);
231 return ret;
232 }
233 }
234
235 /* the page holds a ref on the writeback record */
236 afs_put_writeback(wb);
237 set_page_private(page, 0);
238 ClearPagePrivate(page);
239 goto try_again;
240}
241
242/*
243 * finalise part of a write to a page
244 */
Nick Piggin15b46502008-10-15 22:04:32 -0700245int afs_write_end(struct file *file, struct address_space *mapping,
246 loff_t pos, unsigned len, unsigned copied,
247 struct page *page, void *fsdata)
David Howells31143d52007-05-09 02:33:46 -0700248{
Al Viro496ad9a2013-01-23 17:07:38 -0500249 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
David Howells31143d52007-05-09 02:33:46 -0700250 loff_t i_size, maybe_i_size;
251
Nick Piggin15b46502008-10-15 22:04:32 -0700252 _enter("{%x:%u},{%lx}",
253 vnode->fid.vid, vnode->fid.vnode, page->index);
David Howells31143d52007-05-09 02:33:46 -0700254
Nick Piggin15b46502008-10-15 22:04:32 -0700255 maybe_i_size = pos + copied;
David Howells31143d52007-05-09 02:33:46 -0700256
257 i_size = i_size_read(&vnode->vfs_inode);
258 if (maybe_i_size > i_size) {
259 spin_lock(&vnode->writeback_lock);
260 i_size = i_size_read(&vnode->vfs_inode);
261 if (maybe_i_size > i_size)
262 i_size_write(&vnode->vfs_inode, maybe_i_size);
263 spin_unlock(&vnode->writeback_lock);
264 }
265
266 set_page_dirty(page);
David Howells31143d52007-05-09 02:33:46 -0700267 if (PageDirty(page))
268 _debug("dirtied");
Nick Piggin15b46502008-10-15 22:04:32 -0700269 unlock_page(page);
270 page_cache_release(page);
David Howells31143d52007-05-09 02:33:46 -0700271
Nick Piggin15b46502008-10-15 22:04:32 -0700272 return copied;
David Howells31143d52007-05-09 02:33:46 -0700273}
274
275/*
276 * kill all the pages in the given range
277 */
278static void afs_kill_pages(struct afs_vnode *vnode, bool error,
279 pgoff_t first, pgoff_t last)
280{
281 struct pagevec pv;
282 unsigned count, loop;
283
284 _enter("{%x:%u},%lx-%lx",
285 vnode->fid.vid, vnode->fid.vnode, first, last);
286
287 pagevec_init(&pv, 0);
288
289 do {
290 _debug("kill %lx-%lx", first, last);
291
292 count = last - first + 1;
293 if (count > PAGEVEC_SIZE)
294 count = PAGEVEC_SIZE;
295 pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping,
296 first, count, pv.pages);
297 ASSERTCMP(pv.nr, ==, count);
298
299 for (loop = 0; loop < count; loop++) {
300 ClearPageUptodate(pv.pages[loop]);
301 if (error)
302 SetPageError(pv.pages[loop]);
303 end_page_writeback(pv.pages[loop]);
304 }
305
306 __pagevec_release(&pv);
307 } while (first < last);
308
309 _leave("");
310}
311
312/*
313 * synchronously write back the locked page and any subsequent non-locked dirty
314 * pages also covered by the same writeback record
315 */
316static int afs_write_back_from_locked_page(struct afs_writeback *wb,
317 struct page *primary_page)
318{
319 struct page *pages[8], *page;
320 unsigned long count;
321 unsigned n, offset, to;
322 pgoff_t start, first, last;
323 int loop, ret;
324
325 _enter(",%lx", primary_page->index);
326
327 count = 1;
328 if (!clear_page_dirty_for_io(primary_page))
329 BUG();
330 if (test_set_page_writeback(primary_page))
331 BUG();
332
333 /* find all consecutive lockable dirty pages, stopping when we find a
334 * page that is not immediately lockable, is not dirty or is missing,
335 * or we reach the end of the range */
336 start = primary_page->index;
337 if (start >= wb->last)
338 goto no_more;
339 start++;
340 do {
341 _debug("more %lx [%lx]", start, count);
342 n = wb->last - start + 1;
343 if (n > ARRAY_SIZE(pages))
344 n = ARRAY_SIZE(pages);
345 n = find_get_pages_contig(wb->vnode->vfs_inode.i_mapping,
346 start, n, pages);
347 _debug("fgpc %u", n);
348 if (n == 0)
349 goto no_more;
350 if (pages[0]->index != start) {
David Howells9d577b62007-05-10 22:22:19 -0700351 do {
352 put_page(pages[--n]);
353 } while (n > 0);
David Howells31143d52007-05-09 02:33:46 -0700354 goto no_more;
355 }
356
357 for (loop = 0; loop < n; loop++) {
358 page = pages[loop];
359 if (page->index > wb->last)
360 break;
Nick Piggin529ae9a2008-08-02 12:01:03 +0200361 if (!trylock_page(page))
David Howells31143d52007-05-09 02:33:46 -0700362 break;
363 if (!PageDirty(page) ||
364 page_private(page) != (unsigned long) wb) {
365 unlock_page(page);
366 break;
367 }
368 if (!clear_page_dirty_for_io(page))
369 BUG();
370 if (test_set_page_writeback(page))
371 BUG();
372 unlock_page(page);
373 put_page(page);
374 }
375 count += loop;
376 if (loop < n) {
377 for (; loop < n; loop++)
378 put_page(pages[loop]);
379 goto no_more;
380 }
381
382 start += loop;
383 } while (start <= wb->last && count < 65536);
384
385no_more:
386 /* we now have a contiguous set of dirty pages, each with writeback set
387 * and the dirty mark cleared; the first page is locked and must remain
388 * so, all the rest are unlocked */
389 first = primary_page->index;
390 last = first + count - 1;
391
392 offset = (first == wb->first) ? wb->offset_first : 0;
393 to = (last == wb->last) ? wb->to_last : PAGE_SIZE;
394
395 _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to);
396
397 ret = afs_vnode_store_data(wb, first, last, offset, to);
398 if (ret < 0) {
399 switch (ret) {
400 case -EDQUOT:
401 case -ENOSPC:
402 set_bit(AS_ENOSPC,
403 &wb->vnode->vfs_inode.i_mapping->flags);
404 break;
405 case -EROFS:
406 case -EIO:
407 case -EREMOTEIO:
408 case -EFBIG:
409 case -ENOENT:
410 case -ENOMEDIUM:
411 case -ENXIO:
412 afs_kill_pages(wb->vnode, true, first, last);
413 set_bit(AS_EIO, &wb->vnode->vfs_inode.i_mapping->flags);
414 break;
415 case -EACCES:
416 case -EPERM:
417 case -ENOKEY:
418 case -EKEYEXPIRED:
419 case -EKEYREJECTED:
420 case -EKEYREVOKED:
421 afs_kill_pages(wb->vnode, false, first, last);
422 break;
423 default:
424 break;
425 }
426 } else {
427 ret = count;
428 }
429
430 _leave(" = %d", ret);
431 return ret;
432}
433
434/*
435 * write a page back to the server
436 * - the caller locked the page for us
437 */
438int afs_writepage(struct page *page, struct writeback_control *wbc)
439{
David Howells31143d52007-05-09 02:33:46 -0700440 struct afs_writeback *wb;
441 int ret;
442
443 _enter("{%lx},", page->index);
444
David Howells31143d52007-05-09 02:33:46 -0700445 wb = (struct afs_writeback *) page_private(page);
446 ASSERT(wb != NULL);
447
448 ret = afs_write_back_from_locked_page(wb, page);
449 unlock_page(page);
450 if (ret < 0) {
451 _leave(" = %d", ret);
452 return 0;
453 }
454
455 wbc->nr_to_write -= ret;
David Howells31143d52007-05-09 02:33:46 -0700456
457 _leave(" = 0");
458 return 0;
459}
460
461/*
462 * write a region of pages back to the server
463 */
Adrian Bunkc1206a22007-10-16 23:26:41 -0700464static int afs_writepages_region(struct address_space *mapping,
465 struct writeback_control *wbc,
466 pgoff_t index, pgoff_t end, pgoff_t *_next)
David Howells31143d52007-05-09 02:33:46 -0700467{
David Howells31143d52007-05-09 02:33:46 -0700468 struct afs_writeback *wb;
469 struct page *page;
470 int ret, n;
471
472 _enter(",,%lx,%lx,", index, end);
473
474 do {
475 n = find_get_pages_tag(mapping, &index, PAGECACHE_TAG_DIRTY,
476 1, &page);
477 if (!n)
478 break;
479
480 _debug("wback %lx", page->index);
481
482 if (page->index > end) {
483 *_next = index;
484 page_cache_release(page);
485 _leave(" = 0 [%lx]", *_next);
486 return 0;
487 }
488
489 /* at this point we hold neither mapping->tree_lock nor lock on
490 * the page itself: the page may be truncated or invalidated
491 * (changing page->mapping to NULL), or even swizzled back from
492 * swapper_space to tmpfs file mapping
493 */
494 lock_page(page);
495
496 if (page->mapping != mapping) {
497 unlock_page(page);
498 page_cache_release(page);
499 continue;
500 }
501
502 if (wbc->sync_mode != WB_SYNC_NONE)
503 wait_on_page_writeback(page);
504
505 if (PageWriteback(page) || !PageDirty(page)) {
506 unlock_page(page);
507 continue;
508 }
509
510 wb = (struct afs_writeback *) page_private(page);
511 ASSERT(wb != NULL);
512
513 spin_lock(&wb->vnode->writeback_lock);
514 wb->state = AFS_WBACK_WRITING;
515 spin_unlock(&wb->vnode->writeback_lock);
516
517 ret = afs_write_back_from_locked_page(wb, page);
518 unlock_page(page);
519 page_cache_release(page);
520 if (ret < 0) {
521 _leave(" = %d", ret);
522 return ret;
523 }
524
525 wbc->nr_to_write -= ret;
526
David Howells31143d52007-05-09 02:33:46 -0700527 cond_resched();
528 } while (index < end && wbc->nr_to_write > 0);
529
530 *_next = index;
531 _leave(" = 0 [%lx]", *_next);
532 return 0;
533}
534
535/*
536 * write some of the pending data back to the server
537 */
538int afs_writepages(struct address_space *mapping,
539 struct writeback_control *wbc)
540{
David Howells31143d52007-05-09 02:33:46 -0700541 pgoff_t start, end, next;
542 int ret;
543
544 _enter("");
545
David Howells31143d52007-05-09 02:33:46 -0700546 if (wbc->range_cyclic) {
547 start = mapping->writeback_index;
548 end = -1;
549 ret = afs_writepages_region(mapping, wbc, start, end, &next);
Wu Fengguang1b430be2010-10-26 14:21:26 -0700550 if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
David Howells31143d52007-05-09 02:33:46 -0700551 ret = afs_writepages_region(mapping, wbc, 0, start,
552 &next);
553 mapping->writeback_index = next;
554 } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
555 end = (pgoff_t)(LLONG_MAX >> PAGE_CACHE_SHIFT);
556 ret = afs_writepages_region(mapping, wbc, 0, end, &next);
557 if (wbc->nr_to_write > 0)
558 mapping->writeback_index = next;
559 } else {
560 start = wbc->range_start >> PAGE_CACHE_SHIFT;
561 end = wbc->range_end >> PAGE_CACHE_SHIFT;
562 ret = afs_writepages_region(mapping, wbc, start, end, &next);
563 }
564
565 _leave(" = %d", ret);
566 return ret;
567}
568
569/*
David Howells31143d52007-05-09 02:33:46 -0700570 * completion of write to server
571 */
572void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call)
573{
574 struct afs_writeback *wb = call->wb;
575 struct pagevec pv;
576 unsigned count, loop;
577 pgoff_t first = call->first, last = call->last;
578 bool free_wb;
579
580 _enter("{%x:%u},{%lx-%lx}",
581 vnode->fid.vid, vnode->fid.vnode, first, last);
582
583 ASSERT(wb != NULL);
584
585 pagevec_init(&pv, 0);
586
587 do {
David Howells5bbf5d32007-05-10 03:15:23 -0700588 _debug("done %lx-%lx", first, last);
David Howells31143d52007-05-09 02:33:46 -0700589
590 count = last - first + 1;
591 if (count > PAGEVEC_SIZE)
592 count = PAGEVEC_SIZE;
593 pv.nr = find_get_pages_contig(call->mapping, first, count,
594 pv.pages);
595 ASSERTCMP(pv.nr, ==, count);
596
597 spin_lock(&vnode->writeback_lock);
598 for (loop = 0; loop < count; loop++) {
599 struct page *page = pv.pages[loop];
600 end_page_writeback(page);
601 if (page_private(page) == (unsigned long) wb) {
602 set_page_private(page, 0);
603 ClearPagePrivate(page);
604 wb->usage--;
605 }
606 }
607 free_wb = false;
608 if (wb->usage == 0) {
609 afs_unlink_writeback(wb);
610 free_wb = true;
611 }
612 spin_unlock(&vnode->writeback_lock);
613 first += count;
614 if (free_wb) {
615 afs_free_writeback(wb);
616 wb = NULL;
617 }
618
619 __pagevec_release(&pv);
David Howells5bbf5d32007-05-10 03:15:23 -0700620 } while (first <= last);
David Howells31143d52007-05-09 02:33:46 -0700621
622 _leave("");
623}
624
625/*
626 * write to an AFS file
627 */
Al Viro50b55512014-04-03 14:13:46 -0400628ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from)
David Howells31143d52007-05-09 02:33:46 -0700629{
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;
Al Viro50b55512014-04-03 14:13:46 -0400632 size_t count = iov_iter_count(from);
David Howells31143d52007-05-09 02:33:46 -0700633
Al Viro50b55512014-04-03 14:13:46 -0400634 _enter("{%x.%u},{%zu},",
635 vnode->fid.vid, vnode->fid.vnode, count);
David Howells31143d52007-05-09 02:33:46 -0700636
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
Al Viro50b55512014-04-03 14:13:46 -0400646 result = generic_file_write_iter(iocb, from);
David Howells31143d52007-05-09 02:33:46 -0700647 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}