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31143d5d
DH
1/* 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 */
4343d008 11
4af3c9cc 12#include <linux/backing-dev.h>
31143d5d
DH
13#include <linux/slab.h>
14#include <linux/fs.h>
15#include <linux/pagemap.h>
16#include <linux/writeback.h>
17#include <linux/pagevec.h>
18#include "internal.h"
19
31143d5d
DH
20/*
21 * mark a page as having been made dirty and thus needing writeback
22 */
23int afs_set_page_dirty(struct page *page)
24{
25 _enter("");
26 return __set_page_dirty_nobuffers(page);
27}
28
31143d5d
DH
29/*
30 * partly or wholly fill a page that's under preparation for writing
31 */
32static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
e8e581a8 33 loff_t pos, unsigned int len, struct page *page)
31143d5d 34{
196ee9cd 35 struct afs_read *req;
31143d5d
DH
36 int ret;
37
5e7f2337 38 _enter(",,%llu", (unsigned long long)pos);
31143d5d 39
196ee9cd
DH
40 req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *),
41 GFP_KERNEL);
42 if (!req)
43 return -ENOMEM;
44
45 atomic_set(&req->usage, 1);
46 req->pos = pos;
e8e581a8 47 req->len = len;
196ee9cd
DH
48 req->nr_pages = 1;
49 req->pages[0] = page;
5611ef28 50 get_page(page);
196ee9cd 51
d2ddc776 52 ret = afs_fetch_data(vnode, key, req);
196ee9cd 53 afs_put_read(req);
31143d5d
DH
54 if (ret < 0) {
55 if (ret == -ENOENT) {
56 _debug("got NOENT from server"
57 " - marking file deleted and stale");
58 set_bit(AFS_VNODE_DELETED, &vnode->flags);
59 ret = -ESTALE;
60 }
61 }
62
63 _leave(" = %d", ret);
64 return ret;
65}
66
31143d5d
DH
67/*
68 * prepare to perform part of a write to a page
31143d5d 69 */
15b4650e
NP
70int afs_write_begin(struct file *file, struct address_space *mapping,
71 loff_t pos, unsigned len, unsigned flags,
72 struct page **pagep, void **fsdata)
31143d5d 73{
496ad9aa 74 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
15b4650e 75 struct page *page;
215804a9 76 struct key *key = afs_file_key(file);
4343d008
DH
77 unsigned long priv;
78 unsigned f, from = pos & (PAGE_SIZE - 1);
79 unsigned t, to = from + len;
09cbfeaf 80 pgoff_t index = pos >> PAGE_SHIFT;
31143d5d
DH
81 int ret;
82
83 _enter("{%x:%u},{%lx},%u,%u",
15b4650e 84 vnode->fid.vid, vnode->fid.vnode, index, from, to);
31143d5d 85
4343d008
DH
86 /* We want to store information about how much of a page is altered in
87 * page->private.
88 */
89 BUILD_BUG_ON(PAGE_SIZE > 32768 && sizeof(page->private) < 8);
31143d5d 90
54566b2c 91 page = grab_cache_page_write_begin(mapping, index, flags);
4343d008 92 if (!page)
15b4650e 93 return -ENOMEM;
15b4650e 94
09cbfeaf 95 if (!PageUptodate(page) && len != PAGE_SIZE) {
e8e581a8 96 ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page);
31143d5d 97 if (ret < 0) {
6d06b0d2
DH
98 unlock_page(page);
99 put_page(page);
31143d5d
DH
100 _leave(" = %d [prep]", ret);
101 return ret;
102 }
15b4650e 103 SetPageUptodate(page);
31143d5d
DH
104 }
105
6d06b0d2
DH
106 /* page won't leak in error case: it eventually gets cleaned off LRU */
107 *pagep = page;
108
31143d5d 109try_again:
4343d008
DH
110 /* See if this page is already partially written in a way that we can
111 * merge the new write with.
112 */
113 t = f = 0;
114 if (PagePrivate(page)) {
115 priv = page_private(page);
116 f = priv & AFS_PRIV_MAX;
117 t = priv >> AFS_PRIV_SHIFT;
118 ASSERTCMP(f, <=, t);
31143d5d
DH
119 }
120
4343d008 121 if (f != t) {
5a039c32
DH
122 if (PageWriteback(page)) {
123 trace_afs_page_dirty(vnode, tracepoint_string("alrdy"),
124 page->index, priv);
125 goto flush_conflicting_write;
126 }
4343d008
DH
127 if (to < f || from > t)
128 goto flush_conflicting_write;
129 if (from < f)
130 f = from;
131 if (to > t)
132 t = to;
133 } else {
134 f = from;
135 t = to;
31143d5d
DH
136 }
137
4343d008
DH
138 priv = (unsigned long)t << AFS_PRIV_SHIFT;
139 priv |= f;
13524ab3
DH
140 trace_afs_page_dirty(vnode, tracepoint_string("begin"),
141 page->index, priv);
31143d5d 142 SetPagePrivate(page);
4343d008
DH
143 set_page_private(page, priv);
144 _leave(" = 0");
31143d5d
DH
145 return 0;
146
4343d008
DH
147 /* The previous write and this write aren't adjacent or overlapping, so
148 * flush the page out.
149 */
150flush_conflicting_write:
31143d5d 151 _debug("flush conflict");
4343d008
DH
152 ret = write_one_page(page);
153 if (ret < 0) {
154 _leave(" = %d", ret);
155 return ret;
31143d5d
DH
156 }
157
4343d008
DH
158 ret = lock_page_killable(page);
159 if (ret < 0) {
160 _leave(" = %d", ret);
161 return ret;
162 }
31143d5d
DH
163 goto try_again;
164}
165
166/*
167 * finalise part of a write to a page
168 */
15b4650e
NP
169int afs_write_end(struct file *file, struct address_space *mapping,
170 loff_t pos, unsigned len, unsigned copied,
171 struct page *page, void *fsdata)
31143d5d 172{
496ad9aa 173 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
215804a9 174 struct key *key = afs_file_key(file);
31143d5d 175 loff_t i_size, maybe_i_size;
e8e581a8 176 int ret;
31143d5d 177
15b4650e
NP
178 _enter("{%x:%u},{%lx}",
179 vnode->fid.vid, vnode->fid.vnode, page->index);
31143d5d 180
15b4650e 181 maybe_i_size = pos + copied;
31143d5d
DH
182
183 i_size = i_size_read(&vnode->vfs_inode);
184 if (maybe_i_size > i_size) {
4343d008 185 spin_lock(&vnode->wb_lock);
31143d5d
DH
186 i_size = i_size_read(&vnode->vfs_inode);
187 if (maybe_i_size > i_size)
188 i_size_write(&vnode->vfs_inode, maybe_i_size);
4343d008 189 spin_unlock(&vnode->wb_lock);
31143d5d
DH
190 }
191
e8e581a8
DH
192 if (!PageUptodate(page)) {
193 if (copied < len) {
194 /* Try and load any missing data from the server. The
195 * unmarshalling routine will take care of clearing any
196 * bits that are beyond the EOF.
197 */
198 ret = afs_fill_page(vnode, key, pos + copied,
199 len - copied, page);
200 if (ret < 0)
afae457d 201 goto out;
e8e581a8
DH
202 }
203 SetPageUptodate(page);
204 }
205
31143d5d 206 set_page_dirty(page);
31143d5d
DH
207 if (PageDirty(page))
208 _debug("dirtied");
afae457d
DH
209 ret = copied;
210
211out:
15b4650e 212 unlock_page(page);
09cbfeaf 213 put_page(page);
afae457d 214 return ret;
31143d5d
DH
215}
216
217/*
218 * kill all the pages in the given range
219 */
4343d008 220static void afs_kill_pages(struct address_space *mapping,
31143d5d
DH
221 pgoff_t first, pgoff_t last)
222{
4343d008 223 struct afs_vnode *vnode = AFS_FS_I(mapping->host);
31143d5d
DH
224 struct pagevec pv;
225 unsigned count, loop;
226
227 _enter("{%x:%u},%lx-%lx",
228 vnode->fid.vid, vnode->fid.vnode, first, last);
229
86679820 230 pagevec_init(&pv);
31143d5d
DH
231
232 do {
233 _debug("kill %lx-%lx", first, last);
234
235 count = last - first + 1;
236 if (count > PAGEVEC_SIZE)
237 count = PAGEVEC_SIZE;
4343d008 238 pv.nr = find_get_pages_contig(mapping, first, count, pv.pages);
31143d5d
DH
239 ASSERTCMP(pv.nr, ==, count);
240
241 for (loop = 0; loop < count; loop++) {
7286a35e
DH
242 struct page *page = pv.pages[loop];
243 ClearPageUptodate(page);
4343d008
DH
244 SetPageError(page);
245 end_page_writeback(page);
7286a35e
DH
246 if (page->index >= first)
247 first = page->index + 1;
4343d008
DH
248 lock_page(page);
249 generic_error_remove_page(mapping, page);
31143d5d
DH
250 }
251
252 __pagevec_release(&pv);
4343d008 253 } while (first <= last);
31143d5d
DH
254
255 _leave("");
256}
257
258/*
4343d008
DH
259 * Redirty all the pages in a given range.
260 */
261static void afs_redirty_pages(struct writeback_control *wbc,
262 struct address_space *mapping,
263 pgoff_t first, pgoff_t last)
264{
265 struct afs_vnode *vnode = AFS_FS_I(mapping->host);
266 struct pagevec pv;
267 unsigned count, loop;
268
269 _enter("{%x:%u},%lx-%lx",
270 vnode->fid.vid, vnode->fid.vnode, first, last);
271
487e2c9f 272 pagevec_init(&pv);
4343d008
DH
273
274 do {
275 _debug("redirty %lx-%lx", first, last);
276
277 count = last - first + 1;
278 if (count > PAGEVEC_SIZE)
279 count = PAGEVEC_SIZE;
280 pv.nr = find_get_pages_contig(mapping, first, count, pv.pages);
281 ASSERTCMP(pv.nr, ==, count);
282
283 for (loop = 0; loop < count; loop++) {
284 struct page *page = pv.pages[loop];
285
286 redirty_page_for_writepage(wbc, page);
287 end_page_writeback(page);
288 if (page->index >= first)
289 first = page->index + 1;
290 }
291
292 __pagevec_release(&pv);
293 } while (first <= last);
31143d5d
DH
294
295 _leave("");
296}
297
d2ddc776
DH
298/*
299 * write to a file
300 */
4343d008
DH
301static int afs_store_data(struct address_space *mapping,
302 pgoff_t first, pgoff_t last,
d2ddc776
DH
303 unsigned offset, unsigned to)
304{
4343d008 305 struct afs_vnode *vnode = AFS_FS_I(mapping->host);
d2ddc776 306 struct afs_fs_cursor fc;
4343d008
DH
307 struct afs_wb_key *wbk = NULL;
308 struct list_head *p;
309 int ret = -ENOKEY, ret2;
d2ddc776 310
4343d008 311 _enter("%s{%x:%u.%u},%lx,%lx,%x,%x",
d2ddc776
DH
312 vnode->volume->name,
313 vnode->fid.vid,
314 vnode->fid.vnode,
315 vnode->fid.unique,
d2ddc776
DH
316 first, last, offset, to);
317
4343d008
DH
318 spin_lock(&vnode->wb_lock);
319 p = vnode->wb_keys.next;
320
321 /* Iterate through the list looking for a valid key to use. */
322try_next_key:
323 while (p != &vnode->wb_keys) {
324 wbk = list_entry(p, struct afs_wb_key, vnode_link);
325 _debug("wbk %u", key_serial(wbk->key));
326 ret2 = key_validate(wbk->key);
327 if (ret2 == 0)
328 goto found_key;
329 if (ret == -ENOKEY)
330 ret = ret2;
331 p = p->next;
332 }
333
334 spin_unlock(&vnode->wb_lock);
335 afs_put_wb_key(wbk);
336 _leave(" = %d [no keys]", ret);
337 return ret;
338
339found_key:
340 refcount_inc(&wbk->usage);
341 spin_unlock(&vnode->wb_lock);
342
343 _debug("USE WB KEY %u", key_serial(wbk->key));
344
d2ddc776 345 ret = -ERESTARTSYS;
4343d008 346 if (afs_begin_vnode_operation(&fc, vnode, wbk->key)) {
d2ddc776
DH
347 while (afs_select_fileserver(&fc)) {
348 fc.cb_break = vnode->cb_break + vnode->cb_s_break;
4343d008 349 afs_fs_store_data(&fc, mapping, first, last, offset, to);
d2ddc776
DH
350 }
351
352 afs_check_for_remote_deletion(&fc, fc.vnode);
353 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
354 ret = afs_end_vnode_operation(&fc);
355 }
356
4343d008
DH
357 switch (ret) {
358 case -EACCES:
359 case -EPERM:
360 case -ENOKEY:
361 case -EKEYEXPIRED:
362 case -EKEYREJECTED:
363 case -EKEYREVOKED:
364 _debug("next");
365 spin_lock(&vnode->wb_lock);
366 p = wbk->vnode_link.next;
367 afs_put_wb_key(wbk);
368 goto try_next_key;
369 }
370
371 afs_put_wb_key(wbk);
d2ddc776
DH
372 _leave(" = %d", ret);
373 return ret;
374}
375
31143d5d 376/*
4343d008
DH
377 * Synchronously write back the locked page and any subsequent non-locked dirty
378 * pages.
31143d5d 379 */
4343d008
DH
380static int afs_write_back_from_locked_page(struct address_space *mapping,
381 struct writeback_control *wbc,
382 struct page *primary_page,
383 pgoff_t final_page)
31143d5d 384{
13524ab3 385 struct afs_vnode *vnode = AFS_FS_I(mapping->host);
31143d5d 386 struct page *pages[8], *page;
4343d008
DH
387 unsigned long count, priv;
388 unsigned n, offset, to, f, t;
31143d5d
DH
389 pgoff_t start, first, last;
390 int loop, ret;
391
392 _enter(",%lx", primary_page->index);
393
394 count = 1;
31143d5d
DH
395 if (test_set_page_writeback(primary_page))
396 BUG();
397
4343d008
DH
398 /* Find all consecutive lockable dirty pages that have contiguous
399 * written regions, stopping when we find a page that is not
400 * immediately lockable, is not dirty or is missing, or we reach the
401 * end of the range.
402 */
31143d5d 403 start = primary_page->index;
4343d008
DH
404 priv = page_private(primary_page);
405 offset = priv & AFS_PRIV_MAX;
406 to = priv >> AFS_PRIV_SHIFT;
13524ab3
DH
407 trace_afs_page_dirty(vnode, tracepoint_string("store"),
408 primary_page->index, priv);
4343d008
DH
409
410 WARN_ON(offset == to);
13524ab3
DH
411 if (offset == to)
412 trace_afs_page_dirty(vnode, tracepoint_string("WARN"),
413 primary_page->index, priv);
4343d008
DH
414
415 if (start >= final_page || to < PAGE_SIZE)
31143d5d 416 goto no_more;
4343d008 417
31143d5d
DH
418 start++;
419 do {
420 _debug("more %lx [%lx]", start, count);
4343d008 421 n = final_page - start + 1;
31143d5d
DH
422 if (n > ARRAY_SIZE(pages))
423 n = ARRAY_SIZE(pages);
4343d008 424 n = find_get_pages_contig(mapping, start, ARRAY_SIZE(pages), pages);
31143d5d
DH
425 _debug("fgpc %u", n);
426 if (n == 0)
427 goto no_more;
428 if (pages[0]->index != start) {
9d577b6a
DH
429 do {
430 put_page(pages[--n]);
431 } while (n > 0);
31143d5d
DH
432 goto no_more;
433 }
434
435 for (loop = 0; loop < n; loop++) {
4343d008
DH
436 if (to != PAGE_SIZE)
437 break;
31143d5d 438 page = pages[loop];
4343d008 439 if (page->index > final_page)
31143d5d 440 break;
529ae9aa 441 if (!trylock_page(page))
31143d5d 442 break;
4343d008 443 if (!PageDirty(page) || PageWriteback(page)) {
31143d5d
DH
444 unlock_page(page);
445 break;
446 }
4343d008
DH
447
448 priv = page_private(page);
449 f = priv & AFS_PRIV_MAX;
450 t = priv >> AFS_PRIV_SHIFT;
451 if (f != 0) {
31143d5d
DH
452 unlock_page(page);
453 break;
454 }
4343d008
DH
455 to = t;
456
13524ab3
DH
457 trace_afs_page_dirty(vnode, tracepoint_string("store+"),
458 page->index, priv);
459
31143d5d
DH
460 if (!clear_page_dirty_for_io(page))
461 BUG();
462 if (test_set_page_writeback(page))
463 BUG();
464 unlock_page(page);
465 put_page(page);
466 }
467 count += loop;
468 if (loop < n) {
469 for (; loop < n; loop++)
470 put_page(pages[loop]);
471 goto no_more;
472 }
473
474 start += loop;
4343d008 475 } while (start <= final_page && count < 65536);
31143d5d
DH
476
477no_more:
4343d008
DH
478 /* We now have a contiguous set of dirty pages, each with writeback
479 * set; the first page is still locked at this point, but all the rest
480 * have been unlocked.
481 */
482 unlock_page(primary_page);
483
31143d5d
DH
484 first = primary_page->index;
485 last = first + count - 1;
486
31143d5d
DH
487 _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to);
488
4343d008
DH
489 ret = afs_store_data(mapping, first, last, offset, to);
490 switch (ret) {
491 case 0:
31143d5d 492 ret = count;
4343d008
DH
493 break;
494
495 default:
496 pr_notice("kAFS: Unexpected error from FS.StoreData %d\n", ret);
497 /* Fall through */
498 case -EACCES:
499 case -EPERM:
500 case -ENOKEY:
501 case -EKEYEXPIRED:
502 case -EKEYREJECTED:
503 case -EKEYREVOKED:
504 afs_redirty_pages(wbc, mapping, first, last);
505 mapping_set_error(mapping, ret);
506 break;
507
508 case -EDQUOT:
509 case -ENOSPC:
510 afs_redirty_pages(wbc, mapping, first, last);
511 mapping_set_error(mapping, -ENOSPC);
512 break;
513
514 case -EROFS:
515 case -EIO:
516 case -EREMOTEIO:
517 case -EFBIG:
518 case -ENOENT:
519 case -ENOMEDIUM:
520 case -ENXIO:
521 afs_kill_pages(mapping, first, last);
522 mapping_set_error(mapping, ret);
523 break;
31143d5d
DH
524 }
525
526 _leave(" = %d", ret);
527 return ret;
528}
529
530/*
531 * write a page back to the server
532 * - the caller locked the page for us
533 */
534int afs_writepage(struct page *page, struct writeback_control *wbc)
535{
31143d5d
DH
536 int ret;
537
538 _enter("{%lx},", page->index);
539
4343d008
DH
540 ret = afs_write_back_from_locked_page(page->mapping, wbc, page,
541 wbc->range_end >> PAGE_SHIFT);
31143d5d
DH
542 if (ret < 0) {
543 _leave(" = %d", ret);
544 return 0;
545 }
546
547 wbc->nr_to_write -= ret;
31143d5d
DH
548
549 _leave(" = 0");
550 return 0;
551}
552
553/*
554 * write a region of pages back to the server
555 */
c1206a2c
AB
556static int afs_writepages_region(struct address_space *mapping,
557 struct writeback_control *wbc,
558 pgoff_t index, pgoff_t end, pgoff_t *_next)
31143d5d 559{
31143d5d
DH
560 struct page *page;
561 int ret, n;
562
563 _enter(",,%lx,%lx,", index, end);
564
565 do {
aef6e415
JK
566 n = find_get_pages_range_tag(mapping, &index, end,
567 PAGECACHE_TAG_DIRTY, 1, &page);
31143d5d
DH
568 if (!n)
569 break;
570
571 _debug("wback %lx", page->index);
572
31143d5d
DH
573 /* at this point we hold neither mapping->tree_lock nor lock on
574 * the page itself: the page may be truncated or invalidated
575 * (changing page->mapping to NULL), or even swizzled back from
576 * swapper_space to tmpfs file mapping
577 */
4343d008
DH
578 ret = lock_page_killable(page);
579 if (ret < 0) {
580 put_page(page);
581 _leave(" = %d", ret);
582 return ret;
583 }
31143d5d 584
c5051c7b 585 if (page->mapping != mapping || !PageDirty(page)) {
31143d5d 586 unlock_page(page);
09cbfeaf 587 put_page(page);
31143d5d
DH
588 continue;
589 }
590
c5051c7b 591 if (PageWriteback(page)) {
31143d5d 592 unlock_page(page);
c5051c7b
DH
593 if (wbc->sync_mode != WB_SYNC_NONE)
594 wait_on_page_writeback(page);
29c8bbbd 595 put_page(page);
31143d5d
DH
596 continue;
597 }
598
65a15109
DH
599 if (!clear_page_dirty_for_io(page))
600 BUG();
4343d008 601 ret = afs_write_back_from_locked_page(mapping, wbc, page, end);
09cbfeaf 602 put_page(page);
31143d5d
DH
603 if (ret < 0) {
604 _leave(" = %d", ret);
605 return ret;
606 }
607
608 wbc->nr_to_write -= ret;
609
31143d5d
DH
610 cond_resched();
611 } while (index < end && wbc->nr_to_write > 0);
612
613 *_next = index;
614 _leave(" = 0 [%lx]", *_next);
615 return 0;
616}
617
618/*
619 * write some of the pending data back to the server
620 */
621int afs_writepages(struct address_space *mapping,
622 struct writeback_control *wbc)
623{
31143d5d
DH
624 pgoff_t start, end, next;
625 int ret;
626
627 _enter("");
628
31143d5d
DH
629 if (wbc->range_cyclic) {
630 start = mapping->writeback_index;
631 end = -1;
632 ret = afs_writepages_region(mapping, wbc, start, end, &next);
1b430bee 633 if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
31143d5d
DH
634 ret = afs_writepages_region(mapping, wbc, 0, start,
635 &next);
636 mapping->writeback_index = next;
637 } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
09cbfeaf 638 end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT);
31143d5d
DH
639 ret = afs_writepages_region(mapping, wbc, 0, end, &next);
640 if (wbc->nr_to_write > 0)
641 mapping->writeback_index = next;
642 } else {
09cbfeaf
KS
643 start = wbc->range_start >> PAGE_SHIFT;
644 end = wbc->range_end >> PAGE_SHIFT;
31143d5d
DH
645 ret = afs_writepages_region(mapping, wbc, start, end, &next);
646 }
647
648 _leave(" = %d", ret);
649 return ret;
650}
651
31143d5d
DH
652/*
653 * completion of write to server
654 */
655void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call)
656{
31143d5d 657 struct pagevec pv;
13524ab3 658 unsigned long priv;
31143d5d
DH
659 unsigned count, loop;
660 pgoff_t first = call->first, last = call->last;
31143d5d
DH
661
662 _enter("{%x:%u},{%lx-%lx}",
663 vnode->fid.vid, vnode->fid.vnode, first, last);
664
86679820 665 pagevec_init(&pv);
31143d5d
DH
666
667 do {
5bbf5d39 668 _debug("done %lx-%lx", first, last);
31143d5d
DH
669
670 count = last - first + 1;
671 if (count > PAGEVEC_SIZE)
672 count = PAGEVEC_SIZE;
4343d008
DH
673 pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping,
674 first, count, pv.pages);
31143d5d
DH
675 ASSERTCMP(pv.nr, ==, count);
676
31143d5d 677 for (loop = 0; loop < count; loop++) {
13524ab3
DH
678 priv = page_private(pv.pages[loop]);
679 trace_afs_page_dirty(vnode, tracepoint_string("clear"),
680 pv.pages[loop]->index, priv);
4343d008
DH
681 set_page_private(pv.pages[loop], 0);
682 end_page_writeback(pv.pages[loop]);
31143d5d 683 }
31143d5d 684 first += count;
31143d5d 685 __pagevec_release(&pv);
5bbf5d39 686 } while (first <= last);
31143d5d 687
4343d008 688 afs_prune_wb_keys(vnode);
31143d5d
DH
689 _leave("");
690}
691
692/*
693 * write to an AFS file
694 */
50b5551d 695ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from)
31143d5d 696{
496ad9aa 697 struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp));
31143d5d 698 ssize_t result;
50b5551d 699 size_t count = iov_iter_count(from);
31143d5d 700
50b5551d
AV
701 _enter("{%x.%u},{%zu},",
702 vnode->fid.vid, vnode->fid.vnode, count);
31143d5d
DH
703
704 if (IS_SWAPFILE(&vnode->vfs_inode)) {
705 printk(KERN_INFO
706 "AFS: Attempt to write to active swap file!\n");
707 return -EBUSY;
708 }
709
710 if (!count)
711 return 0;
712
50b5551d 713 result = generic_file_write_iter(iocb, from);
31143d5d 714
31143d5d
DH
715 _leave(" = %zd", result);
716 return result;
717}
718
31143d5d
DH
719/*
720 * flush any dirty pages for this process, and check for write errors.
721 * - the return status from this call provides a reliable indication of
722 * whether any write errors occurred for this process.
723 */
02c24a82 724int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
31143d5d 725{
3c981bfc 726 struct inode *inode = file_inode(file);
3c981bfc 727 struct afs_vnode *vnode = AFS_FS_I(inode);
31143d5d 728
3c981bfc
AV
729 _enter("{%x:%u},{n=%pD},%d",
730 vnode->fid.vid, vnode->fid.vnode, file,
31143d5d
DH
731 datasync);
732
4343d008 733 return file_write_and_wait_range(file, start, end);
31143d5d 734}
9b3f26c9 735
58fed94d
DH
736/*
737 * Flush out all outstanding writes on a file opened for writing when it is
738 * closed.
739 */
740int afs_flush(struct file *file, fl_owner_t id)
741{
742 _enter("");
743
744 if ((file->f_mode & FMODE_WRITE) == 0)
745 return 0;
746
747 return vfs_fsync(file, 0);
748}
749
9b3f26c9
DH
750/*
751 * notification that a previously read-only page is about to become writable
752 * - if it returns an error, the caller will deliver a bus error signal
753 */
1cf7a151 754int afs_page_mkwrite(struct vm_fault *vmf)
9b3f26c9 755{
1cf7a151
DH
756 struct file *file = vmf->vma->vm_file;
757 struct inode *inode = file_inode(file);
758 struct afs_vnode *vnode = AFS_FS_I(inode);
759 unsigned long priv;
9b3f26c9
DH
760
761 _enter("{{%x:%u}},{%lx}",
1cf7a151 762 vnode->fid.vid, vnode->fid.vnode, vmf->page->index);
9b3f26c9 763
1cf7a151 764 sb_start_pagefault(inode->i_sb);
9b3f26c9 765
1cf7a151
DH
766 /* Wait for the page to be written to the cache before we allow it to
767 * be modified. We then assume the entire page will need writing back.
768 */
9b3f26c9 769#ifdef CONFIG_AFS_FSCACHE
1cf7a151 770 fscache_wait_on_page_write(vnode->cache, vmf->page);
9b3f26c9
DH
771#endif
772
1cf7a151
DH
773 if (PageWriteback(vmf->page) &&
774 wait_on_page_bit_killable(vmf->page, PG_writeback) < 0)
775 return VM_FAULT_RETRY;
776
777 if (lock_page_killable(vmf->page) < 0)
778 return VM_FAULT_RETRY;
779
780 /* We mustn't change page->private until writeback is complete as that
781 * details the portion of the page we need to write back and we might
782 * need to redirty the page if there's a problem.
783 */
784 wait_on_page_writeback(vmf->page);
785
786 priv = (unsigned long)PAGE_SIZE << AFS_PRIV_SHIFT; /* To */
787 priv |= 0; /* From */
13524ab3
DH
788 trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"),
789 vmf->page->index, priv);
1cf7a151
DH
790 SetPagePrivate(vmf->page);
791 set_page_private(vmf->page, priv);
792
793 sb_end_pagefault(inode->i_sb);
794 return VM_FAULT_LOCKED;
9b3f26c9 795}
4343d008
DH
796
797/*
798 * Prune the keys cached for writeback. The caller must hold vnode->wb_lock.
799 */
800void afs_prune_wb_keys(struct afs_vnode *vnode)
801{
802 LIST_HEAD(graveyard);
803 struct afs_wb_key *wbk, *tmp;
804
805 /* Discard unused keys */
806 spin_lock(&vnode->wb_lock);
807
808 if (!mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_WRITEBACK) &&
809 !mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_DIRTY)) {
810 list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) {
811 if (refcount_read(&wbk->usage) == 1)
812 list_move(&wbk->vnode_link, &graveyard);
813 }
814 }
815
816 spin_unlock(&vnode->wb_lock);
817
818 while (!list_empty(&graveyard)) {
819 wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link);
820 list_del(&wbk->vnode_link);
821 afs_put_wb_key(wbk);
822 }
823}
824
825/*
826 * Clean up a page during invalidation.
827 */
828int afs_launder_page(struct page *page)
829{
830 struct address_space *mapping = page->mapping;
831 struct afs_vnode *vnode = AFS_FS_I(mapping->host);
832 unsigned long priv;
833 unsigned int f, t;
834 int ret = 0;
835
836 _enter("{%lx}", page->index);
837
838 priv = page_private(page);
839 if (clear_page_dirty_for_io(page)) {
840 f = 0;
841 t = PAGE_SIZE;
842 if (PagePrivate(page)) {
843 f = priv & AFS_PRIV_MAX;
844 t = priv >> AFS_PRIV_SHIFT;
845 }
846
13524ab3
DH
847 trace_afs_page_dirty(vnode, tracepoint_string("launder"),
848 page->index, priv);
4343d008
DH
849 ret = afs_store_data(mapping, page->index, page->index, t, f);
850 }
851
13524ab3
DH
852 trace_afs_page_dirty(vnode, tracepoint_string("laundered"),
853 page->index, priv);
4343d008
DH
854 set_page_private(page, 0);
855 ClearPagePrivate(page);
856
857#ifdef CONFIG_AFS_FSCACHE
858 if (PageFsCache(page)) {
859 fscache_wait_on_page_write(vnode->cache, page);
860 fscache_uncache_page(vnode->cache, page);
861 }
862#endif
863 return ret;
9b3f26c9 864}