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Commit | Line | Data |
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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 | */ | |
4af3c9cc | 11 | #include <linux/backing-dev.h> |
31143d5d DH |
12 | #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 | ||
19 | static 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 | */ | |
25 | int 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 | */ | |
35 | static 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 | */ | |
57 | static 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 | */ | |
67 | void 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 | */ | |
86 | static int afs_fill_page(struct afs_vnode *vnode, struct key *key, | |
e8e581a8 | 87 | loff_t pos, unsigned int len, struct page *page) |
31143d5d | 88 | { |
196ee9cd | 89 | struct afs_read *req; |
31143d5d DH |
90 | int ret; |
91 | ||
5e7f2337 | 92 | _enter(",,%llu", (unsigned long long)pos); |
31143d5d | 93 | |
196ee9cd DH |
94 | 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; | |
e8e581a8 | 101 | req->len = len; |
196ee9cd DH |
102 | req->nr_pages = 1; |
103 | req->pages[0] = page; | |
5611ef28 | 104 | get_page(page); |
196ee9cd | 105 | |
196ee9cd DH |
106 | ret = afs_vnode_fetch_data(vnode, key, req); |
107 | afs_put_read(req); | |
31143d5d DH |
108 | 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 | ||
31143d5d DH |
121 | /* |
122 | * prepare to perform part of a write to a page | |
31143d5d | 123 | */ |
15b4650e NP |
124 | int afs_write_begin(struct file *file, struct address_space *mapping, |
125 | loff_t pos, unsigned len, unsigned flags, | |
126 | struct page **pagep, void **fsdata) | |
31143d5d DH |
127 | { |
128 | struct afs_writeback *candidate, *wb; | |
496ad9aa | 129 | struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
15b4650e | 130 | struct page *page; |
31143d5d | 131 | struct key *key = file->private_data; |
09cbfeaf | 132 | unsigned from = pos & (PAGE_SIZE - 1); |
15b4650e | 133 | unsigned to = from + len; |
09cbfeaf | 134 | pgoff_t index = pos >> PAGE_SHIFT; |
31143d5d DH |
135 | int ret; |
136 | ||
137 | _enter("{%x:%u},{%lx},%u,%u", | |
15b4650e | 138 | vnode->fid.vid, vnode->fid.vnode, index, from, to); |
31143d5d DH |
139 | |
140 | candidate = kzalloc(sizeof(*candidate), GFP_KERNEL); | |
141 | if (!candidate) | |
142 | return -ENOMEM; | |
143 | candidate->vnode = vnode; | |
15b4650e NP |
144 | candidate->first = candidate->last = index; |
145 | candidate->offset_first = from; | |
31143d5d | 146 | candidate->to_last = to; |
f129ccc9 | 147 | INIT_LIST_HEAD(&candidate->link); |
31143d5d DH |
148 | candidate->usage = 1; |
149 | candidate->state = AFS_WBACK_PENDING; | |
150 | init_waitqueue_head(&candidate->waitq); | |
151 | ||
54566b2c | 152 | page = grab_cache_page_write_begin(mapping, index, flags); |
15b4650e NP |
153 | if (!page) { |
154 | kfree(candidate); | |
155 | return -ENOMEM; | |
156 | } | |
157 | *pagep = page; | |
158 | /* page won't leak in error case: it eventually gets cleaned off LRU */ | |
159 | ||
09cbfeaf | 160 | if (!PageUptodate(page) && len != PAGE_SIZE) { |
e8e581a8 | 161 | ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page); |
31143d5d DH |
162 | if (ret < 0) { |
163 | kfree(candidate); | |
164 | _leave(" = %d [prep]", ret); | |
165 | return ret; | |
166 | } | |
15b4650e | 167 | SetPageUptodate(page); |
31143d5d DH |
168 | } |
169 | ||
170 | try_again: | |
31143d5d DH |
171 | spin_lock(&vnode->writeback_lock); |
172 | ||
173 | /* see if this page is already pending a writeback under a suitable key | |
174 | * - if so we can just join onto that one */ | |
175 | wb = (struct afs_writeback *) page_private(page); | |
176 | if (wb) { | |
177 | if (wb->key == key && wb->state == AFS_WBACK_PENDING) | |
178 | goto subsume_in_current_wb; | |
179 | goto flush_conflicting_wb; | |
180 | } | |
181 | ||
182 | if (index > 0) { | |
183 | /* see if we can find an already pending writeback that we can | |
184 | * append this page to */ | |
185 | list_for_each_entry(wb, &vnode->writebacks, link) { | |
186 | if (wb->last == index - 1 && wb->key == key && | |
187 | wb->state == AFS_WBACK_PENDING) | |
188 | goto append_to_previous_wb; | |
189 | } | |
190 | } | |
191 | ||
192 | list_add_tail(&candidate->link, &vnode->writebacks); | |
193 | candidate->key = key_get(key); | |
194 | spin_unlock(&vnode->writeback_lock); | |
195 | SetPagePrivate(page); | |
196 | set_page_private(page, (unsigned long) candidate); | |
197 | _leave(" = 0 [new]"); | |
198 | return 0; | |
199 | ||
200 | subsume_in_current_wb: | |
201 | _debug("subsume"); | |
202 | ASSERTRANGE(wb->first, <=, index, <=, wb->last); | |
15b4650e NP |
203 | if (index == wb->first && from < wb->offset_first) |
204 | wb->offset_first = from; | |
31143d5d DH |
205 | if (index == wb->last && to > wb->to_last) |
206 | wb->to_last = to; | |
207 | spin_unlock(&vnode->writeback_lock); | |
208 | kfree(candidate); | |
209 | _leave(" = 0 [sub]"); | |
210 | return 0; | |
211 | ||
212 | append_to_previous_wb: | |
213 | _debug("append into %lx-%lx", wb->first, wb->last); | |
214 | wb->usage++; | |
215 | wb->last++; | |
216 | wb->to_last = to; | |
217 | spin_unlock(&vnode->writeback_lock); | |
218 | SetPagePrivate(page); | |
219 | set_page_private(page, (unsigned long) wb); | |
220 | kfree(candidate); | |
221 | _leave(" = 0 [app]"); | |
222 | return 0; | |
223 | ||
224 | /* the page is currently bound to another context, so if it's dirty we | |
225 | * need to flush it before we can use the new context */ | |
226 | flush_conflicting_wb: | |
227 | _debug("flush conflict"); | |
228 | if (wb->state == AFS_WBACK_PENDING) | |
229 | wb->state = AFS_WBACK_CONFLICTING; | |
230 | spin_unlock(&vnode->writeback_lock); | |
231 | if (PageDirty(page)) { | |
232 | ret = afs_write_back_from_locked_page(wb, page); | |
233 | if (ret < 0) { | |
234 | afs_put_writeback(candidate); | |
235 | _leave(" = %d", ret); | |
236 | return ret; | |
237 | } | |
238 | } | |
239 | ||
240 | /* the page holds a ref on the writeback record */ | |
241 | afs_put_writeback(wb); | |
242 | set_page_private(page, 0); | |
243 | ClearPagePrivate(page); | |
244 | goto try_again; | |
245 | } | |
246 | ||
247 | /* | |
248 | * finalise part of a write to a page | |
249 | */ | |
15b4650e NP |
250 | int afs_write_end(struct file *file, struct address_space *mapping, |
251 | loff_t pos, unsigned len, unsigned copied, | |
252 | struct page *page, void *fsdata) | |
31143d5d | 253 | { |
496ad9aa | 254 | struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
e8e581a8 | 255 | struct key *key = file->private_data; |
31143d5d | 256 | loff_t i_size, maybe_i_size; |
e8e581a8 | 257 | int ret; |
31143d5d | 258 | |
15b4650e NP |
259 | _enter("{%x:%u},{%lx}", |
260 | vnode->fid.vid, vnode->fid.vnode, page->index); | |
31143d5d | 261 | |
15b4650e | 262 | maybe_i_size = pos + copied; |
31143d5d DH |
263 | |
264 | i_size = i_size_read(&vnode->vfs_inode); | |
265 | if (maybe_i_size > i_size) { | |
266 | spin_lock(&vnode->writeback_lock); | |
267 | i_size = i_size_read(&vnode->vfs_inode); | |
268 | if (maybe_i_size > i_size) | |
269 | i_size_write(&vnode->vfs_inode, maybe_i_size); | |
270 | spin_unlock(&vnode->writeback_lock); | |
271 | } | |
272 | ||
e8e581a8 DH |
273 | if (!PageUptodate(page)) { |
274 | if (copied < len) { | |
275 | /* Try and load any missing data from the server. The | |
276 | * unmarshalling routine will take care of clearing any | |
277 | * bits that are beyond the EOF. | |
278 | */ | |
279 | ret = afs_fill_page(vnode, key, pos + copied, | |
280 | len - copied, page); | |
281 | if (ret < 0) | |
282 | return ret; | |
283 | } | |
284 | SetPageUptodate(page); | |
285 | } | |
286 | ||
31143d5d | 287 | set_page_dirty(page); |
31143d5d DH |
288 | if (PageDirty(page)) |
289 | _debug("dirtied"); | |
15b4650e | 290 | unlock_page(page); |
09cbfeaf | 291 | put_page(page); |
31143d5d | 292 | |
15b4650e | 293 | return copied; |
31143d5d DH |
294 | } |
295 | ||
296 | /* | |
297 | * kill all the pages in the given range | |
298 | */ | |
299 | static void afs_kill_pages(struct afs_vnode *vnode, bool error, | |
300 | pgoff_t first, pgoff_t last) | |
301 | { | |
302 | struct pagevec pv; | |
303 | unsigned count, loop; | |
304 | ||
305 | _enter("{%x:%u},%lx-%lx", | |
306 | vnode->fid.vid, vnode->fid.vnode, first, last); | |
307 | ||
308 | pagevec_init(&pv, 0); | |
309 | ||
310 | do { | |
311 | _debug("kill %lx-%lx", first, last); | |
312 | ||
313 | count = last - first + 1; | |
314 | if (count > PAGEVEC_SIZE) | |
315 | count = PAGEVEC_SIZE; | |
316 | pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping, | |
317 | first, count, pv.pages); | |
318 | ASSERTCMP(pv.nr, ==, count); | |
319 | ||
320 | for (loop = 0; loop < count; loop++) { | |
321 | ClearPageUptodate(pv.pages[loop]); | |
322 | if (error) | |
323 | SetPageError(pv.pages[loop]); | |
324 | end_page_writeback(pv.pages[loop]); | |
325 | } | |
326 | ||
327 | __pagevec_release(&pv); | |
328 | } while (first < last); | |
329 | ||
330 | _leave(""); | |
331 | } | |
332 | ||
333 | /* | |
334 | * synchronously write back the locked page and any subsequent non-locked dirty | |
335 | * pages also covered by the same writeback record | |
336 | */ | |
337 | static int afs_write_back_from_locked_page(struct afs_writeback *wb, | |
338 | struct page *primary_page) | |
339 | { | |
340 | struct page *pages[8], *page; | |
341 | unsigned long count; | |
342 | unsigned n, offset, to; | |
343 | pgoff_t start, first, last; | |
344 | int loop, ret; | |
345 | ||
346 | _enter(",%lx", primary_page->index); | |
347 | ||
348 | count = 1; | |
349 | if (!clear_page_dirty_for_io(primary_page)) | |
350 | BUG(); | |
351 | if (test_set_page_writeback(primary_page)) | |
352 | BUG(); | |
353 | ||
354 | /* find all consecutive lockable dirty pages, stopping when we find a | |
355 | * page that is not immediately lockable, is not dirty or is missing, | |
356 | * or we reach the end of the range */ | |
357 | start = primary_page->index; | |
358 | if (start >= wb->last) | |
359 | goto no_more; | |
360 | start++; | |
361 | do { | |
362 | _debug("more %lx [%lx]", start, count); | |
363 | n = wb->last - start + 1; | |
364 | if (n > ARRAY_SIZE(pages)) | |
365 | n = ARRAY_SIZE(pages); | |
366 | n = find_get_pages_contig(wb->vnode->vfs_inode.i_mapping, | |
367 | start, n, pages); | |
368 | _debug("fgpc %u", n); | |
369 | if (n == 0) | |
370 | goto no_more; | |
371 | if (pages[0]->index != start) { | |
9d577b6a DH |
372 | do { |
373 | put_page(pages[--n]); | |
374 | } while (n > 0); | |
31143d5d DH |
375 | goto no_more; |
376 | } | |
377 | ||
378 | for (loop = 0; loop < n; loop++) { | |
379 | page = pages[loop]; | |
380 | if (page->index > wb->last) | |
381 | break; | |
529ae9aa | 382 | if (!trylock_page(page)) |
31143d5d DH |
383 | break; |
384 | if (!PageDirty(page) || | |
385 | page_private(page) != (unsigned long) wb) { | |
386 | unlock_page(page); | |
387 | break; | |
388 | } | |
389 | if (!clear_page_dirty_for_io(page)) | |
390 | BUG(); | |
391 | if (test_set_page_writeback(page)) | |
392 | BUG(); | |
393 | unlock_page(page); | |
394 | put_page(page); | |
395 | } | |
396 | count += loop; | |
397 | if (loop < n) { | |
398 | for (; loop < n; loop++) | |
399 | put_page(pages[loop]); | |
400 | goto no_more; | |
401 | } | |
402 | ||
403 | start += loop; | |
404 | } while (start <= wb->last && count < 65536); | |
405 | ||
406 | no_more: | |
407 | /* we now have a contiguous set of dirty pages, each with writeback set | |
408 | * and the dirty mark cleared; the first page is locked and must remain | |
409 | * so, all the rest are unlocked */ | |
410 | first = primary_page->index; | |
411 | last = first + count - 1; | |
412 | ||
413 | offset = (first == wb->first) ? wb->offset_first : 0; | |
414 | to = (last == wb->last) ? wb->to_last : PAGE_SIZE; | |
415 | ||
416 | _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to); | |
417 | ||
418 | ret = afs_vnode_store_data(wb, first, last, offset, to); | |
419 | if (ret < 0) { | |
420 | switch (ret) { | |
421 | case -EDQUOT: | |
422 | case -ENOSPC: | |
5114a97a | 423 | mapping_set_error(wb->vnode->vfs_inode.i_mapping, -ENOSPC); |
31143d5d DH |
424 | break; |
425 | case -EROFS: | |
426 | case -EIO: | |
427 | case -EREMOTEIO: | |
428 | case -EFBIG: | |
429 | case -ENOENT: | |
430 | case -ENOMEDIUM: | |
431 | case -ENXIO: | |
432 | afs_kill_pages(wb->vnode, true, first, last); | |
5114a97a | 433 | mapping_set_error(wb->vnode->vfs_inode.i_mapping, -EIO); |
31143d5d DH |
434 | break; |
435 | case -EACCES: | |
436 | case -EPERM: | |
437 | case -ENOKEY: | |
438 | case -EKEYEXPIRED: | |
439 | case -EKEYREJECTED: | |
440 | case -EKEYREVOKED: | |
441 | afs_kill_pages(wb->vnode, false, first, last); | |
442 | break; | |
443 | default: | |
444 | break; | |
445 | } | |
446 | } else { | |
447 | ret = count; | |
448 | } | |
449 | ||
450 | _leave(" = %d", ret); | |
451 | return ret; | |
452 | } | |
453 | ||
454 | /* | |
455 | * write a page back to the server | |
456 | * - the caller locked the page for us | |
457 | */ | |
458 | int afs_writepage(struct page *page, struct writeback_control *wbc) | |
459 | { | |
31143d5d DH |
460 | struct afs_writeback *wb; |
461 | int ret; | |
462 | ||
463 | _enter("{%lx},", page->index); | |
464 | ||
31143d5d DH |
465 | wb = (struct afs_writeback *) page_private(page); |
466 | ASSERT(wb != NULL); | |
467 | ||
468 | ret = afs_write_back_from_locked_page(wb, page); | |
469 | unlock_page(page); | |
470 | if (ret < 0) { | |
471 | _leave(" = %d", ret); | |
472 | return 0; | |
473 | } | |
474 | ||
475 | wbc->nr_to_write -= ret; | |
31143d5d DH |
476 | |
477 | _leave(" = 0"); | |
478 | return 0; | |
479 | } | |
480 | ||
481 | /* | |
482 | * write a region of pages back to the server | |
483 | */ | |
c1206a2c AB |
484 | static int afs_writepages_region(struct address_space *mapping, |
485 | struct writeback_control *wbc, | |
486 | pgoff_t index, pgoff_t end, pgoff_t *_next) | |
31143d5d | 487 | { |
31143d5d DH |
488 | struct afs_writeback *wb; |
489 | struct page *page; | |
490 | int ret, n; | |
491 | ||
492 | _enter(",,%lx,%lx,", index, end); | |
493 | ||
494 | do { | |
495 | n = find_get_pages_tag(mapping, &index, PAGECACHE_TAG_DIRTY, | |
496 | 1, &page); | |
497 | if (!n) | |
498 | break; | |
499 | ||
500 | _debug("wback %lx", page->index); | |
501 | ||
502 | if (page->index > end) { | |
503 | *_next = index; | |
09cbfeaf | 504 | put_page(page); |
31143d5d DH |
505 | _leave(" = 0 [%lx]", *_next); |
506 | return 0; | |
507 | } | |
508 | ||
509 | /* at this point we hold neither mapping->tree_lock nor lock on | |
510 | * the page itself: the page may be truncated or invalidated | |
511 | * (changing page->mapping to NULL), or even swizzled back from | |
512 | * swapper_space to tmpfs file mapping | |
513 | */ | |
514 | lock_page(page); | |
515 | ||
516 | if (page->mapping != mapping) { | |
517 | unlock_page(page); | |
09cbfeaf | 518 | put_page(page); |
31143d5d DH |
519 | continue; |
520 | } | |
521 | ||
522 | if (wbc->sync_mode != WB_SYNC_NONE) | |
523 | wait_on_page_writeback(page); | |
524 | ||
525 | if (PageWriteback(page) || !PageDirty(page)) { | |
526 | unlock_page(page); | |
29c8bbbd | 527 | put_page(page); |
31143d5d DH |
528 | continue; |
529 | } | |
530 | ||
531 | wb = (struct afs_writeback *) page_private(page); | |
532 | ASSERT(wb != NULL); | |
533 | ||
534 | spin_lock(&wb->vnode->writeback_lock); | |
535 | wb->state = AFS_WBACK_WRITING; | |
536 | spin_unlock(&wb->vnode->writeback_lock); | |
537 | ||
538 | ret = afs_write_back_from_locked_page(wb, page); | |
539 | unlock_page(page); | |
09cbfeaf | 540 | put_page(page); |
31143d5d DH |
541 | if (ret < 0) { |
542 | _leave(" = %d", ret); | |
543 | return ret; | |
544 | } | |
545 | ||
546 | wbc->nr_to_write -= ret; | |
547 | ||
31143d5d DH |
548 | cond_resched(); |
549 | } while (index < end && wbc->nr_to_write > 0); | |
550 | ||
551 | *_next = index; | |
552 | _leave(" = 0 [%lx]", *_next); | |
553 | return 0; | |
554 | } | |
555 | ||
556 | /* | |
557 | * write some of the pending data back to the server | |
558 | */ | |
559 | int afs_writepages(struct address_space *mapping, | |
560 | struct writeback_control *wbc) | |
561 | { | |
31143d5d DH |
562 | pgoff_t start, end, next; |
563 | int ret; | |
564 | ||
565 | _enter(""); | |
566 | ||
31143d5d DH |
567 | if (wbc->range_cyclic) { |
568 | start = mapping->writeback_index; | |
569 | end = -1; | |
570 | ret = afs_writepages_region(mapping, wbc, start, end, &next); | |
1b430bee | 571 | if (start > 0 && wbc->nr_to_write > 0 && ret == 0) |
31143d5d DH |
572 | ret = afs_writepages_region(mapping, wbc, 0, start, |
573 | &next); | |
574 | mapping->writeback_index = next; | |
575 | } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { | |
09cbfeaf | 576 | end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT); |
31143d5d DH |
577 | ret = afs_writepages_region(mapping, wbc, 0, end, &next); |
578 | if (wbc->nr_to_write > 0) | |
579 | mapping->writeback_index = next; | |
580 | } else { | |
09cbfeaf KS |
581 | start = wbc->range_start >> PAGE_SHIFT; |
582 | end = wbc->range_end >> PAGE_SHIFT; | |
31143d5d DH |
583 | ret = afs_writepages_region(mapping, wbc, start, end, &next); |
584 | } | |
585 | ||
586 | _leave(" = %d", ret); | |
587 | return ret; | |
588 | } | |
589 | ||
31143d5d DH |
590 | /* |
591 | * completion of write to server | |
592 | */ | |
593 | void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call) | |
594 | { | |
595 | struct afs_writeback *wb = call->wb; | |
596 | struct pagevec pv; | |
597 | unsigned count, loop; | |
598 | pgoff_t first = call->first, last = call->last; | |
599 | bool free_wb; | |
600 | ||
601 | _enter("{%x:%u},{%lx-%lx}", | |
602 | vnode->fid.vid, vnode->fid.vnode, first, last); | |
603 | ||
604 | ASSERT(wb != NULL); | |
605 | ||
606 | pagevec_init(&pv, 0); | |
607 | ||
608 | do { | |
5bbf5d39 | 609 | _debug("done %lx-%lx", first, last); |
31143d5d DH |
610 | |
611 | count = last - first + 1; | |
612 | if (count > PAGEVEC_SIZE) | |
613 | count = PAGEVEC_SIZE; | |
614 | pv.nr = find_get_pages_contig(call->mapping, first, count, | |
615 | pv.pages); | |
616 | ASSERTCMP(pv.nr, ==, count); | |
617 | ||
618 | spin_lock(&vnode->writeback_lock); | |
619 | for (loop = 0; loop < count; loop++) { | |
620 | struct page *page = pv.pages[loop]; | |
621 | end_page_writeback(page); | |
622 | if (page_private(page) == (unsigned long) wb) { | |
623 | set_page_private(page, 0); | |
624 | ClearPagePrivate(page); | |
625 | wb->usage--; | |
626 | } | |
627 | } | |
628 | free_wb = false; | |
629 | if (wb->usage == 0) { | |
630 | afs_unlink_writeback(wb); | |
631 | free_wb = true; | |
632 | } | |
633 | spin_unlock(&vnode->writeback_lock); | |
634 | first += count; | |
635 | if (free_wb) { | |
636 | afs_free_writeback(wb); | |
637 | wb = NULL; | |
638 | } | |
639 | ||
640 | __pagevec_release(&pv); | |
5bbf5d39 | 641 | } while (first <= last); |
31143d5d DH |
642 | |
643 | _leave(""); | |
644 | } | |
645 | ||
646 | /* | |
647 | * write to an AFS file | |
648 | */ | |
50b5551d | 649 | ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) |
31143d5d | 650 | { |
496ad9aa | 651 | struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); |
31143d5d | 652 | ssize_t result; |
50b5551d | 653 | size_t count = iov_iter_count(from); |
31143d5d | 654 | |
50b5551d AV |
655 | _enter("{%x.%u},{%zu},", |
656 | vnode->fid.vid, vnode->fid.vnode, count); | |
31143d5d DH |
657 | |
658 | if (IS_SWAPFILE(&vnode->vfs_inode)) { | |
659 | printk(KERN_INFO | |
660 | "AFS: Attempt to write to active swap file!\n"); | |
661 | return -EBUSY; | |
662 | } | |
663 | ||
664 | if (!count) | |
665 | return 0; | |
666 | ||
50b5551d | 667 | result = generic_file_write_iter(iocb, from); |
31143d5d | 668 | |
31143d5d DH |
669 | _leave(" = %zd", result); |
670 | return result; | |
671 | } | |
672 | ||
673 | /* | |
674 | * flush the vnode to the fileserver | |
675 | */ | |
676 | int afs_writeback_all(struct afs_vnode *vnode) | |
677 | { | |
678 | struct address_space *mapping = vnode->vfs_inode.i_mapping; | |
679 | struct writeback_control wbc = { | |
31143d5d DH |
680 | .sync_mode = WB_SYNC_ALL, |
681 | .nr_to_write = LONG_MAX, | |
31143d5d DH |
682 | .range_cyclic = 1, |
683 | }; | |
684 | int ret; | |
685 | ||
686 | _enter(""); | |
687 | ||
688 | ret = mapping->a_ops->writepages(mapping, &wbc); | |
689 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); | |
690 | ||
691 | _leave(" = %d", ret); | |
692 | return ret; | |
693 | } | |
694 | ||
695 | /* | |
696 | * flush any dirty pages for this process, and check for write errors. | |
697 | * - the return status from this call provides a reliable indication of | |
698 | * whether any write errors occurred for this process. | |
699 | */ | |
02c24a82 | 700 | int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
31143d5d | 701 | { |
3c981bfc | 702 | struct inode *inode = file_inode(file); |
31143d5d | 703 | struct afs_writeback *wb, *xwb; |
3c981bfc | 704 | struct afs_vnode *vnode = AFS_FS_I(inode); |
31143d5d DH |
705 | int ret; |
706 | ||
3c981bfc AV |
707 | _enter("{%x:%u},{n=%pD},%d", |
708 | vnode->fid.vid, vnode->fid.vnode, file, | |
31143d5d DH |
709 | datasync); |
710 | ||
02c24a82 JB |
711 | ret = filemap_write_and_wait_range(inode->i_mapping, start, end); |
712 | if (ret) | |
713 | return ret; | |
5955102c | 714 | inode_lock(inode); |
02c24a82 | 715 | |
31143d5d DH |
716 | /* use a writeback record as a marker in the queue - when this reaches |
717 | * the front of the queue, all the outstanding writes are either | |
718 | * completed or rejected */ | |
719 | wb = kzalloc(sizeof(*wb), GFP_KERNEL); | |
02c24a82 JB |
720 | if (!wb) { |
721 | ret = -ENOMEM; | |
722 | goto out; | |
723 | } | |
31143d5d DH |
724 | wb->vnode = vnode; |
725 | wb->first = 0; | |
726 | wb->last = -1; | |
727 | wb->offset_first = 0; | |
728 | wb->to_last = PAGE_SIZE; | |
729 | wb->usage = 1; | |
730 | wb->state = AFS_WBACK_SYNCING; | |
731 | init_waitqueue_head(&wb->waitq); | |
732 | ||
733 | spin_lock(&vnode->writeback_lock); | |
734 | list_for_each_entry(xwb, &vnode->writebacks, link) { | |
735 | if (xwb->state == AFS_WBACK_PENDING) | |
736 | xwb->state = AFS_WBACK_CONFLICTING; | |
737 | } | |
738 | list_add_tail(&wb->link, &vnode->writebacks); | |
739 | spin_unlock(&vnode->writeback_lock); | |
740 | ||
741 | /* push all the outstanding writebacks to the server */ | |
742 | ret = afs_writeback_all(vnode); | |
743 | if (ret < 0) { | |
744 | afs_put_writeback(wb); | |
745 | _leave(" = %d [wb]", ret); | |
02c24a82 | 746 | goto out; |
31143d5d DH |
747 | } |
748 | ||
749 | /* wait for the preceding writes to actually complete */ | |
750 | ret = wait_event_interruptible(wb->waitq, | |
751 | wb->state == AFS_WBACK_COMPLETE || | |
752 | vnode->writebacks.next == &wb->link); | |
753 | afs_put_writeback(wb); | |
754 | _leave(" = %d", ret); | |
02c24a82 | 755 | out: |
5955102c | 756 | inode_unlock(inode); |
31143d5d DH |
757 | return ret; |
758 | } | |
9b3f26c9 DH |
759 | |
760 | /* | |
761 | * notification that a previously read-only page is about to become writable | |
762 | * - if it returns an error, the caller will deliver a bus error signal | |
763 | */ | |
764 | int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page) | |
765 | { | |
766 | struct afs_vnode *vnode = AFS_FS_I(vma->vm_file->f_mapping->host); | |
767 | ||
768 | _enter("{{%x:%u}},{%lx}", | |
769 | vnode->fid.vid, vnode->fid.vnode, page->index); | |
770 | ||
771 | /* wait for the page to be written to the cache before we allow it to | |
772 | * be modified */ | |
773 | #ifdef CONFIG_AFS_FSCACHE | |
774 | fscache_wait_on_page_write(vnode->cache, page); | |
775 | #endif | |
776 | ||
777 | _leave(" = 0"); | |
778 | return 0; | |
779 | } |