blob: 6e13e96c3db0d3371e46afdaffd8ee8336832a57 [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 ([email protected])
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,
David Howellse8e581a2017-03-16 16:27:44 +000087 loff_t pos, unsigned int len, struct page *page)
David Howells31143d52007-05-09 02:33:46 -070088{
David Howells196ee9c2017-01-05 10:38:34 +000089 struct afs_read *req;
David Howells31143d52007-05-09 02:33:46 -070090 int ret;
91
Anton Blanchard5e7f2332011-06-13 22:31:12 +010092 _enter(",,%llu", (unsigned long long)pos);
David Howells31143d52007-05-09 02:33:46 -070093
David Howells196ee9c2017-01-05 10:38:34 +000094 req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *),
95 GFP_KERNEL);
96 if (!req)
97 return -ENOMEM;
98
99 atomic_set(&req->usage, 1);
100 req->pos = pos;
David Howellse8e581a2017-03-16 16:27:44 +0000101 req->len = len;
David Howells196ee9c2017-01-05 10:38:34 +0000102 req->nr_pages = 1;
103 req->pages[0] = page;
David Howells5611ef22017-03-16 16:27:43 +0000104 get_page(page);
David Howells196ee9c2017-01-05 10:38:34 +0000105
David Howells196ee9c2017-01-05 10:38:34 +0000106 ret = afs_vnode_fetch_data(vnode, key, req);
107 afs_put_read(req);
David Howells31143d52007-05-09 02:33:46 -0700108 if (ret < 0) {
109 if (ret == -ENOENT) {
110 _debug("got NOENT from server"
111 " - marking file deleted and stale");
112 set_bit(AFS_VNODE_DELETED, &vnode->flags);
113 ret = -ESTALE;
114 }
115 }
116
117 _leave(" = %d", ret);
118 return ret;
119}
120
121/*
David Howells31143d52007-05-09 02:33:46 -0700122 * prepare to perform part of a write to a page
David Howells31143d52007-05-09 02:33:46 -0700123 */
Nick Piggin15b46502008-10-15 22:04:32 -0700124int afs_write_begin(struct file *file, struct address_space *mapping,
125 loff_t pos, unsigned len, unsigned flags,
126 struct page **pagep, void **fsdata)
David Howells31143d52007-05-09 02:33:46 -0700127{
128 struct afs_writeback *candidate, *wb;
Al Viro496ad9a2013-01-23 17:07:38 -0500129 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
Nick Piggin15b46502008-10-15 22:04:32 -0700130 struct page *page;
David Howells31143d52007-05-09 02:33:46 -0700131 struct key *key = file->private_data;
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300132 unsigned from = pos & (PAGE_SIZE - 1);
Nick Piggin15b46502008-10-15 22:04:32 -0700133 unsigned to = from + len;
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300134 pgoff_t index = pos >> PAGE_SHIFT;
David Howells31143d52007-05-09 02:33:46 -0700135 int ret;
136
137 _enter("{%x:%u},{%lx},%u,%u",
Nick Piggin15b46502008-10-15 22:04:32 -0700138 vnode->fid.vid, vnode->fid.vnode, index, from, to);
David Howells31143d52007-05-09 02:33:46 -0700139
140 candidate = kzalloc(sizeof(*candidate), GFP_KERNEL);
141 if (!candidate)
142 return -ENOMEM;
143 candidate->vnode = vnode;
Nick Piggin15b46502008-10-15 22:04:32 -0700144 candidate->first = candidate->last = index;
145 candidate->offset_first = from;
David Howells31143d52007-05-09 02:33:46 -0700146 candidate->to_last = to;
Anton Blanchardf129ccc2011-02-25 15:33:02 +0000147 INIT_LIST_HEAD(&candidate->link);
David Howells31143d52007-05-09 02:33:46 -0700148 candidate->usage = 1;
149 candidate->state = AFS_WBACK_PENDING;
150 init_waitqueue_head(&candidate->waitq);
151
Nick Piggin54566b22009-01-04 12:00:53 -0800152 page = grab_cache_page_write_begin(mapping, index, flags);
Nick Piggin15b46502008-10-15 22:04:32 -0700153 if (!page) {
154 kfree(candidate);
155 return -ENOMEM;
156 }
Nick Piggin15b46502008-10-15 22:04:32 -0700157
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300158 if (!PageUptodate(page) && len != PAGE_SIZE) {
David Howellse8e581a2017-03-16 16:27:44 +0000159 ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page);
David Howells31143d52007-05-09 02:33:46 -0700160 if (ret < 0) {
David Howells6d06b0d2017-03-16 16:27:48 +0000161 unlock_page(page);
162 put_page(page);
David Howells31143d52007-05-09 02:33:46 -0700163 kfree(candidate);
164 _leave(" = %d [prep]", ret);
165 return ret;
166 }
Nick Piggin15b46502008-10-15 22:04:32 -0700167 SetPageUptodate(page);
David Howells31143d52007-05-09 02:33:46 -0700168 }
169
David Howells6d06b0d2017-03-16 16:27:48 +0000170 /* page won't leak in error case: it eventually gets cleaned off LRU */
171 *pagep = page;
172
David Howells31143d52007-05-09 02:33:46 -0700173try_again:
David Howells31143d52007-05-09 02:33:46 -0700174 spin_lock(&vnode->writeback_lock);
175
176 /* see if this page is already pending a writeback under a suitable key
177 * - if so we can just join onto that one */
178 wb = (struct afs_writeback *) page_private(page);
179 if (wb) {
180 if (wb->key == key && wb->state == AFS_WBACK_PENDING)
181 goto subsume_in_current_wb;
182 goto flush_conflicting_wb;
183 }
184
185 if (index > 0) {
186 /* see if we can find an already pending writeback that we can
187 * append this page to */
188 list_for_each_entry(wb, &vnode->writebacks, link) {
189 if (wb->last == index - 1 && wb->key == key &&
190 wb->state == AFS_WBACK_PENDING)
191 goto append_to_previous_wb;
192 }
193 }
194
195 list_add_tail(&candidate->link, &vnode->writebacks);
196 candidate->key = key_get(key);
197 spin_unlock(&vnode->writeback_lock);
198 SetPagePrivate(page);
199 set_page_private(page, (unsigned long) candidate);
200 _leave(" = 0 [new]");
201 return 0;
202
203subsume_in_current_wb:
204 _debug("subsume");
205 ASSERTRANGE(wb->first, <=, index, <=, wb->last);
Nick Piggin15b46502008-10-15 22:04:32 -0700206 if (index == wb->first && from < wb->offset_first)
207 wb->offset_first = from;
David Howells31143d52007-05-09 02:33:46 -0700208 if (index == wb->last && to > wb->to_last)
209 wb->to_last = to;
210 spin_unlock(&vnode->writeback_lock);
211 kfree(candidate);
212 _leave(" = 0 [sub]");
213 return 0;
214
215append_to_previous_wb:
216 _debug("append into %lx-%lx", wb->first, wb->last);
217 wb->usage++;
218 wb->last++;
219 wb->to_last = to;
220 spin_unlock(&vnode->writeback_lock);
221 SetPagePrivate(page);
222 set_page_private(page, (unsigned long) wb);
223 kfree(candidate);
224 _leave(" = 0 [app]");
225 return 0;
226
227 /* the page is currently bound to another context, so if it's dirty we
228 * need to flush it before we can use the new context */
229flush_conflicting_wb:
230 _debug("flush conflict");
231 if (wb->state == AFS_WBACK_PENDING)
232 wb->state = AFS_WBACK_CONFLICTING;
233 spin_unlock(&vnode->writeback_lock);
234 if (PageDirty(page)) {
235 ret = afs_write_back_from_locked_page(wb, page);
236 if (ret < 0) {
237 afs_put_writeback(candidate);
238 _leave(" = %d", ret);
239 return ret;
240 }
241 }
242
243 /* the page holds a ref on the writeback record */
244 afs_put_writeback(wb);
245 set_page_private(page, 0);
246 ClearPagePrivate(page);
247 goto try_again;
248}
249
250/*
251 * finalise part of a write to a page
252 */
Nick Piggin15b46502008-10-15 22:04:32 -0700253int afs_write_end(struct file *file, struct address_space *mapping,
254 loff_t pos, unsigned len, unsigned copied,
255 struct page *page, void *fsdata)
David Howells31143d52007-05-09 02:33:46 -0700256{
Al Viro496ad9a2013-01-23 17:07:38 -0500257 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
David Howellse8e581a2017-03-16 16:27:44 +0000258 struct key *key = file->private_data;
David Howells31143d52007-05-09 02:33:46 -0700259 loff_t i_size, maybe_i_size;
David Howellse8e581a2017-03-16 16:27:44 +0000260 int ret;
David Howells31143d52007-05-09 02:33:46 -0700261
Nick Piggin15b46502008-10-15 22:04:32 -0700262 _enter("{%x:%u},{%lx}",
263 vnode->fid.vid, vnode->fid.vnode, page->index);
David Howells31143d52007-05-09 02:33:46 -0700264
Nick Piggin15b46502008-10-15 22:04:32 -0700265 maybe_i_size = pos + copied;
David Howells31143d52007-05-09 02:33:46 -0700266
267 i_size = i_size_read(&vnode->vfs_inode);
268 if (maybe_i_size > i_size) {
269 spin_lock(&vnode->writeback_lock);
270 i_size = i_size_read(&vnode->vfs_inode);
271 if (maybe_i_size > i_size)
272 i_size_write(&vnode->vfs_inode, maybe_i_size);
273 spin_unlock(&vnode->writeback_lock);
274 }
275
David Howellse8e581a2017-03-16 16:27:44 +0000276 if (!PageUptodate(page)) {
277 if (copied < len) {
278 /* Try and load any missing data from the server. The
279 * unmarshalling routine will take care of clearing any
280 * bits that are beyond the EOF.
281 */
282 ret = afs_fill_page(vnode, key, pos + copied,
283 len - copied, page);
284 if (ret < 0)
285 return ret;
286 }
287 SetPageUptodate(page);
288 }
289
David Howells31143d52007-05-09 02:33:46 -0700290 set_page_dirty(page);
David Howells31143d52007-05-09 02:33:46 -0700291 if (PageDirty(page))
292 _debug("dirtied");
Nick Piggin15b46502008-10-15 22:04:32 -0700293 unlock_page(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300294 put_page(page);
David Howells31143d52007-05-09 02:33:46 -0700295
Nick Piggin15b46502008-10-15 22:04:32 -0700296 return copied;
David Howells31143d52007-05-09 02:33:46 -0700297}
298
299/*
300 * kill all the pages in the given range
301 */
302static void afs_kill_pages(struct afs_vnode *vnode, bool error,
303 pgoff_t first, pgoff_t last)
304{
305 struct pagevec pv;
306 unsigned count, loop;
307
308 _enter("{%x:%u},%lx-%lx",
309 vnode->fid.vid, vnode->fid.vnode, first, last);
310
311 pagevec_init(&pv, 0);
312
313 do {
314 _debug("kill %lx-%lx", first, last);
315
316 count = last - first + 1;
317 if (count > PAGEVEC_SIZE)
318 count = PAGEVEC_SIZE;
319 pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping,
320 first, count, pv.pages);
321 ASSERTCMP(pv.nr, ==, count);
322
323 for (loop = 0; loop < count; loop++) {
324 ClearPageUptodate(pv.pages[loop]);
325 if (error)
326 SetPageError(pv.pages[loop]);
327 end_page_writeback(pv.pages[loop]);
328 }
329
330 __pagevec_release(&pv);
331 } while (first < last);
332
333 _leave("");
334}
335
336/*
337 * synchronously write back the locked page and any subsequent non-locked dirty
338 * pages also covered by the same writeback record
339 */
340static int afs_write_back_from_locked_page(struct afs_writeback *wb,
341 struct page *primary_page)
342{
343 struct page *pages[8], *page;
344 unsigned long count;
345 unsigned n, offset, to;
346 pgoff_t start, first, last;
347 int loop, ret;
348
349 _enter(",%lx", primary_page->index);
350
351 count = 1;
352 if (!clear_page_dirty_for_io(primary_page))
353 BUG();
354 if (test_set_page_writeback(primary_page))
355 BUG();
356
357 /* find all consecutive lockable dirty pages, stopping when we find a
358 * page that is not immediately lockable, is not dirty or is missing,
359 * or we reach the end of the range */
360 start = primary_page->index;
361 if (start >= wb->last)
362 goto no_more;
363 start++;
364 do {
365 _debug("more %lx [%lx]", start, count);
366 n = wb->last - start + 1;
367 if (n > ARRAY_SIZE(pages))
368 n = ARRAY_SIZE(pages);
369 n = find_get_pages_contig(wb->vnode->vfs_inode.i_mapping,
370 start, n, pages);
371 _debug("fgpc %u", n);
372 if (n == 0)
373 goto no_more;
374 if (pages[0]->index != start) {
David Howells9d577b62007-05-10 22:22:19 -0700375 do {
376 put_page(pages[--n]);
377 } while (n > 0);
David Howells31143d52007-05-09 02:33:46 -0700378 goto no_more;
379 }
380
381 for (loop = 0; loop < n; loop++) {
382 page = pages[loop];
383 if (page->index > wb->last)
384 break;
Nick Piggin529ae9a2008-08-02 12:01:03 +0200385 if (!trylock_page(page))
David Howells31143d52007-05-09 02:33:46 -0700386 break;
387 if (!PageDirty(page) ||
388 page_private(page) != (unsigned long) wb) {
389 unlock_page(page);
390 break;
391 }
392 if (!clear_page_dirty_for_io(page))
393 BUG();
394 if (test_set_page_writeback(page))
395 BUG();
396 unlock_page(page);
397 put_page(page);
398 }
399 count += loop;
400 if (loop < n) {
401 for (; loop < n; loop++)
402 put_page(pages[loop]);
403 goto no_more;
404 }
405
406 start += loop;
407 } while (start <= wb->last && count < 65536);
408
409no_more:
410 /* we now have a contiguous set of dirty pages, each with writeback set
411 * and the dirty mark cleared; the first page is locked and must remain
412 * so, all the rest are unlocked */
413 first = primary_page->index;
414 last = first + count - 1;
415
416 offset = (first == wb->first) ? wb->offset_first : 0;
417 to = (last == wb->last) ? wb->to_last : PAGE_SIZE;
418
419 _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to);
420
421 ret = afs_vnode_store_data(wb, first, last, offset, to);
422 if (ret < 0) {
423 switch (ret) {
424 case -EDQUOT:
425 case -ENOSPC:
Michal Hocko5114a972016-10-11 13:56:01 -0700426 mapping_set_error(wb->vnode->vfs_inode.i_mapping, -ENOSPC);
David Howells31143d52007-05-09 02:33:46 -0700427 break;
428 case -EROFS:
429 case -EIO:
430 case -EREMOTEIO:
431 case -EFBIG:
432 case -ENOENT:
433 case -ENOMEDIUM:
434 case -ENXIO:
435 afs_kill_pages(wb->vnode, true, first, last);
Michal Hocko5114a972016-10-11 13:56:01 -0700436 mapping_set_error(wb->vnode->vfs_inode.i_mapping, -EIO);
David Howells31143d52007-05-09 02:33:46 -0700437 break;
438 case -EACCES:
439 case -EPERM:
440 case -ENOKEY:
441 case -EKEYEXPIRED:
442 case -EKEYREJECTED:
443 case -EKEYREVOKED:
444 afs_kill_pages(wb->vnode, false, first, last);
445 break;
446 default:
447 break;
448 }
449 } else {
450 ret = count;
451 }
452
453 _leave(" = %d", ret);
454 return ret;
455}
456
457/*
458 * write a page back to the server
459 * - the caller locked the page for us
460 */
461int afs_writepage(struct page *page, struct writeback_control *wbc)
462{
David Howells31143d52007-05-09 02:33:46 -0700463 struct afs_writeback *wb;
464 int ret;
465
466 _enter("{%lx},", page->index);
467
David Howells31143d52007-05-09 02:33:46 -0700468 wb = (struct afs_writeback *) page_private(page);
469 ASSERT(wb != NULL);
470
471 ret = afs_write_back_from_locked_page(wb, page);
472 unlock_page(page);
473 if (ret < 0) {
474 _leave(" = %d", ret);
475 return 0;
476 }
477
478 wbc->nr_to_write -= ret;
David Howells31143d52007-05-09 02:33:46 -0700479
480 _leave(" = 0");
481 return 0;
482}
483
484/*
485 * write a region of pages back to the server
486 */
Adrian Bunkc1206a22007-10-16 23:26:41 -0700487static int afs_writepages_region(struct address_space *mapping,
488 struct writeback_control *wbc,
489 pgoff_t index, pgoff_t end, pgoff_t *_next)
David Howells31143d52007-05-09 02:33:46 -0700490{
David Howells31143d52007-05-09 02:33:46 -0700491 struct afs_writeback *wb;
492 struct page *page;
493 int ret, n;
494
495 _enter(",,%lx,%lx,", index, end);
496
497 do {
498 n = find_get_pages_tag(mapping, &index, PAGECACHE_TAG_DIRTY,
499 1, &page);
500 if (!n)
501 break;
502
503 _debug("wback %lx", page->index);
504
505 if (page->index > end) {
506 *_next = index;
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300507 put_page(page);
David Howells31143d52007-05-09 02:33:46 -0700508 _leave(" = 0 [%lx]", *_next);
509 return 0;
510 }
511
512 /* at this point we hold neither mapping->tree_lock nor lock on
513 * the page itself: the page may be truncated or invalidated
514 * (changing page->mapping to NULL), or even swizzled back from
515 * swapper_space to tmpfs file mapping
516 */
517 lock_page(page);
518
519 if (page->mapping != mapping) {
520 unlock_page(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300521 put_page(page);
David Howells31143d52007-05-09 02:33:46 -0700522 continue;
523 }
524
525 if (wbc->sync_mode != WB_SYNC_NONE)
526 wait_on_page_writeback(page);
527
528 if (PageWriteback(page) || !PageDirty(page)) {
529 unlock_page(page);
David Howells29c8bbb2017-03-16 16:27:43 +0000530 put_page(page);
David Howells31143d52007-05-09 02:33:46 -0700531 continue;
532 }
533
534 wb = (struct afs_writeback *) page_private(page);
535 ASSERT(wb != NULL);
536
537 spin_lock(&wb->vnode->writeback_lock);
538 wb->state = AFS_WBACK_WRITING;
539 spin_unlock(&wb->vnode->writeback_lock);
540
541 ret = afs_write_back_from_locked_page(wb, page);
542 unlock_page(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300543 put_page(page);
David Howells31143d52007-05-09 02:33:46 -0700544 if (ret < 0) {
545 _leave(" = %d", ret);
546 return ret;
547 }
548
549 wbc->nr_to_write -= ret;
550
David Howells31143d52007-05-09 02:33:46 -0700551 cond_resched();
552 } while (index < end && wbc->nr_to_write > 0);
553
554 *_next = index;
555 _leave(" = 0 [%lx]", *_next);
556 return 0;
557}
558
559/*
560 * write some of the pending data back to the server
561 */
562int afs_writepages(struct address_space *mapping,
563 struct writeback_control *wbc)
564{
David Howells31143d52007-05-09 02:33:46 -0700565 pgoff_t start, end, next;
566 int ret;
567
568 _enter("");
569
David Howells31143d52007-05-09 02:33:46 -0700570 if (wbc->range_cyclic) {
571 start = mapping->writeback_index;
572 end = -1;
573 ret = afs_writepages_region(mapping, wbc, start, end, &next);
Wu Fengguang1b430be2010-10-26 14:21:26 -0700574 if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
David Howells31143d52007-05-09 02:33:46 -0700575 ret = afs_writepages_region(mapping, wbc, 0, start,
576 &next);
577 mapping->writeback_index = next;
578 } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300579 end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT);
David Howells31143d52007-05-09 02:33:46 -0700580 ret = afs_writepages_region(mapping, wbc, 0, end, &next);
581 if (wbc->nr_to_write > 0)
582 mapping->writeback_index = next;
583 } else {
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300584 start = wbc->range_start >> PAGE_SHIFT;
585 end = wbc->range_end >> PAGE_SHIFT;
David Howells31143d52007-05-09 02:33:46 -0700586 ret = afs_writepages_region(mapping, wbc, start, end, &next);
587 }
588
589 _leave(" = %d", ret);
590 return ret;
591}
592
593/*
David Howells31143d52007-05-09 02:33:46 -0700594 * completion of write to server
595 */
596void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call)
597{
598 struct afs_writeback *wb = call->wb;
599 struct pagevec pv;
600 unsigned count, loop;
601 pgoff_t first = call->first, last = call->last;
602 bool free_wb;
603
604 _enter("{%x:%u},{%lx-%lx}",
605 vnode->fid.vid, vnode->fid.vnode, first, last);
606
607 ASSERT(wb != NULL);
608
609 pagevec_init(&pv, 0);
610
611 do {
David Howells5bbf5d32007-05-10 03:15:23 -0700612 _debug("done %lx-%lx", first, last);
David Howells31143d52007-05-09 02:33:46 -0700613
614 count = last - first + 1;
615 if (count > PAGEVEC_SIZE)
616 count = PAGEVEC_SIZE;
617 pv.nr = find_get_pages_contig(call->mapping, first, count,
618 pv.pages);
619 ASSERTCMP(pv.nr, ==, count);
620
621 spin_lock(&vnode->writeback_lock);
622 for (loop = 0; loop < count; loop++) {
623 struct page *page = pv.pages[loop];
624 end_page_writeback(page);
625 if (page_private(page) == (unsigned long) wb) {
626 set_page_private(page, 0);
627 ClearPagePrivate(page);
628 wb->usage--;
629 }
630 }
631 free_wb = false;
632 if (wb->usage == 0) {
633 afs_unlink_writeback(wb);
634 free_wb = true;
635 }
636 spin_unlock(&vnode->writeback_lock);
637 first += count;
638 if (free_wb) {
639 afs_free_writeback(wb);
640 wb = NULL;
641 }
642
643 __pagevec_release(&pv);
David Howells5bbf5d32007-05-10 03:15:23 -0700644 } while (first <= last);
David Howells31143d52007-05-09 02:33:46 -0700645
646 _leave("");
647}
648
649/*
650 * write to an AFS file
651 */
Al Viro50b55512014-04-03 14:13:46 -0400652ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from)
David Howells31143d52007-05-09 02:33:46 -0700653{
Al Viro496ad9a2013-01-23 17:07:38 -0500654 struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp));
David Howells31143d52007-05-09 02:33:46 -0700655 ssize_t result;
Al Viro50b55512014-04-03 14:13:46 -0400656 size_t count = iov_iter_count(from);
David Howells31143d52007-05-09 02:33:46 -0700657
Al Viro50b55512014-04-03 14:13:46 -0400658 _enter("{%x.%u},{%zu},",
659 vnode->fid.vid, vnode->fid.vnode, count);
David Howells31143d52007-05-09 02:33:46 -0700660
661 if (IS_SWAPFILE(&vnode->vfs_inode)) {
662 printk(KERN_INFO
663 "AFS: Attempt to write to active swap file!\n");
664 return -EBUSY;
665 }
666
667 if (!count)
668 return 0;
669
Al Viro50b55512014-04-03 14:13:46 -0400670 result = generic_file_write_iter(iocb, from);
David Howells31143d52007-05-09 02:33:46 -0700671
David Howells31143d52007-05-09 02:33:46 -0700672 _leave(" = %zd", result);
673 return result;
674}
675
676/*
677 * flush the vnode to the fileserver
678 */
679int afs_writeback_all(struct afs_vnode *vnode)
680{
681 struct address_space *mapping = vnode->vfs_inode.i_mapping;
682 struct writeback_control wbc = {
David Howells31143d52007-05-09 02:33:46 -0700683 .sync_mode = WB_SYNC_ALL,
684 .nr_to_write = LONG_MAX,
David Howells31143d52007-05-09 02:33:46 -0700685 .range_cyclic = 1,
686 };
687 int ret;
688
689 _enter("");
690
691 ret = mapping->a_ops->writepages(mapping, &wbc);
692 __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
693
694 _leave(" = %d", ret);
695 return ret;
696}
697
698/*
699 * flush any dirty pages for this process, and check for write errors.
700 * - the return status from this call provides a reliable indication of
701 * whether any write errors occurred for this process.
702 */
Josef Bacik02c24a82011-07-16 20:44:56 -0400703int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
David Howells31143d52007-05-09 02:33:46 -0700704{
Al Viro3c981bf2013-09-03 13:37:45 -0400705 struct inode *inode = file_inode(file);
David Howells31143d52007-05-09 02:33:46 -0700706 struct afs_writeback *wb, *xwb;
Al Viro3c981bf2013-09-03 13:37:45 -0400707 struct afs_vnode *vnode = AFS_FS_I(inode);
David Howells31143d52007-05-09 02:33:46 -0700708 int ret;
709
Al Viro3c981bf2013-09-03 13:37:45 -0400710 _enter("{%x:%u},{n=%pD},%d",
711 vnode->fid.vid, vnode->fid.vnode, file,
David Howells31143d52007-05-09 02:33:46 -0700712 datasync);
713
Josef Bacik02c24a82011-07-16 20:44:56 -0400714 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
715 if (ret)
716 return ret;
Al Viro59551022016-01-22 15:40:57 -0500717 inode_lock(inode);
Josef Bacik02c24a82011-07-16 20:44:56 -0400718
David Howells31143d52007-05-09 02:33:46 -0700719 /* use a writeback record as a marker in the queue - when this reaches
720 * the front of the queue, all the outstanding writes are either
721 * completed or rejected */
722 wb = kzalloc(sizeof(*wb), GFP_KERNEL);
Josef Bacik02c24a82011-07-16 20:44:56 -0400723 if (!wb) {
724 ret = -ENOMEM;
725 goto out;
726 }
David Howells31143d52007-05-09 02:33:46 -0700727 wb->vnode = vnode;
728 wb->first = 0;
729 wb->last = -1;
730 wb->offset_first = 0;
731 wb->to_last = PAGE_SIZE;
732 wb->usage = 1;
733 wb->state = AFS_WBACK_SYNCING;
734 init_waitqueue_head(&wb->waitq);
735
736 spin_lock(&vnode->writeback_lock);
737 list_for_each_entry(xwb, &vnode->writebacks, link) {
738 if (xwb->state == AFS_WBACK_PENDING)
739 xwb->state = AFS_WBACK_CONFLICTING;
740 }
741 list_add_tail(&wb->link, &vnode->writebacks);
742 spin_unlock(&vnode->writeback_lock);
743
744 /* push all the outstanding writebacks to the server */
745 ret = afs_writeback_all(vnode);
746 if (ret < 0) {
747 afs_put_writeback(wb);
748 _leave(" = %d [wb]", ret);
Josef Bacik02c24a82011-07-16 20:44:56 -0400749 goto out;
David Howells31143d52007-05-09 02:33:46 -0700750 }
751
752 /* wait for the preceding writes to actually complete */
753 ret = wait_event_interruptible(wb->waitq,
754 wb->state == AFS_WBACK_COMPLETE ||
755 vnode->writebacks.next == &wb->link);
756 afs_put_writeback(wb);
757 _leave(" = %d", ret);
Josef Bacik02c24a82011-07-16 20:44:56 -0400758out:
Al Viro59551022016-01-22 15:40:57 -0500759 inode_unlock(inode);
David Howells31143d52007-05-09 02:33:46 -0700760 return ret;
761}
David Howells9b3f26c2009-04-03 16:42:41 +0100762
763/*
David Howells58fed942017-03-16 16:27:45 +0000764 * Flush out all outstanding writes on a file opened for writing when it is
765 * closed.
766 */
767int afs_flush(struct file *file, fl_owner_t id)
768{
769 _enter("");
770
771 if ((file->f_mode & FMODE_WRITE) == 0)
772 return 0;
773
774 return vfs_fsync(file, 0);
775}
776
777/*
David Howells9b3f26c2009-04-03 16:42:41 +0100778 * notification that a previously read-only page is about to become writable
779 * - if it returns an error, the caller will deliver a bus error signal
780 */
781int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
782{
783 struct afs_vnode *vnode = AFS_FS_I(vma->vm_file->f_mapping->host);
784
785 _enter("{{%x:%u}},{%lx}",
786 vnode->fid.vid, vnode->fid.vnode, page->index);
787
788 /* wait for the page to be written to the cache before we allow it to
789 * be modified */
790#ifdef CONFIG_AFS_FSCACHE
791 fscache_wait_on_page_write(vnode->cache, page);
792#endif
793
794 _leave(" = 0");
795 return 0;
796}