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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, | |
5e7f2337 | 87 | loff_t pos, struct page *page) |
31143d5d | 88 | { |
196ee9cd | 89 | struct afs_read *req; |
15b4650e | 90 | loff_t i_size; |
31143d5d DH |
91 | int ret; |
92 | ||
5e7f2337 | 93 | _enter(",,%llu", (unsigned long long)pos); |
31143d5d | 94 | |
196ee9cd DH |
95 | req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *), |
96 | GFP_KERNEL); | |
97 | if (!req) | |
98 | return -ENOMEM; | |
99 | ||
100 | atomic_set(&req->usage, 1); | |
101 | req->pos = pos; | |
102 | req->nr_pages = 1; | |
103 | req->pages[0] = page; | |
104 | ||
15b4650e | 105 | i_size = i_size_read(&vnode->vfs_inode); |
09cbfeaf | 106 | if (pos + PAGE_SIZE > i_size) |
196ee9cd | 107 | req->len = i_size - pos; |
15b4650e | 108 | else |
196ee9cd | 109 | req->len = PAGE_SIZE; |
15b4650e | 110 | |
196ee9cd DH |
111 | ret = afs_vnode_fetch_data(vnode, key, req); |
112 | afs_put_read(req); | |
31143d5d DH |
113 | if (ret < 0) { |
114 | if (ret == -ENOENT) { | |
115 | _debug("got NOENT from server" | |
116 | " - marking file deleted and stale"); | |
117 | set_bit(AFS_VNODE_DELETED, &vnode->flags); | |
118 | ret = -ESTALE; | |
119 | } | |
120 | } | |
121 | ||
122 | _leave(" = %d", ret); | |
123 | return ret; | |
124 | } | |
125 | ||
31143d5d DH |
126 | /* |
127 | * prepare to perform part of a write to a page | |
31143d5d | 128 | */ |
15b4650e NP |
129 | int afs_write_begin(struct file *file, struct address_space *mapping, |
130 | loff_t pos, unsigned len, unsigned flags, | |
131 | struct page **pagep, void **fsdata) | |
31143d5d DH |
132 | { |
133 | struct afs_writeback *candidate, *wb; | |
496ad9aa | 134 | struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
15b4650e | 135 | struct page *page; |
31143d5d | 136 | struct key *key = file->private_data; |
09cbfeaf | 137 | unsigned from = pos & (PAGE_SIZE - 1); |
15b4650e | 138 | unsigned to = from + len; |
09cbfeaf | 139 | pgoff_t index = pos >> PAGE_SHIFT; |
31143d5d DH |
140 | int ret; |
141 | ||
142 | _enter("{%x:%u},{%lx},%u,%u", | |
15b4650e | 143 | vnode->fid.vid, vnode->fid.vnode, index, from, to); |
31143d5d DH |
144 | |
145 | candidate = kzalloc(sizeof(*candidate), GFP_KERNEL); | |
146 | if (!candidate) | |
147 | return -ENOMEM; | |
148 | candidate->vnode = vnode; | |
15b4650e NP |
149 | candidate->first = candidate->last = index; |
150 | candidate->offset_first = from; | |
31143d5d | 151 | candidate->to_last = to; |
f129ccc9 | 152 | INIT_LIST_HEAD(&candidate->link); |
31143d5d DH |
153 | candidate->usage = 1; |
154 | candidate->state = AFS_WBACK_PENDING; | |
155 | init_waitqueue_head(&candidate->waitq); | |
156 | ||
54566b2c | 157 | page = grab_cache_page_write_begin(mapping, index, flags); |
15b4650e NP |
158 | if (!page) { |
159 | kfree(candidate); | |
160 | return -ENOMEM; | |
161 | } | |
162 | *pagep = page; | |
163 | /* page won't leak in error case: it eventually gets cleaned off LRU */ | |
164 | ||
09cbfeaf KS |
165 | if (!PageUptodate(page) && len != PAGE_SIZE) { |
166 | ret = afs_fill_page(vnode, key, index << PAGE_SHIFT, page); | |
31143d5d DH |
167 | if (ret < 0) { |
168 | kfree(candidate); | |
169 | _leave(" = %d [prep]", ret); | |
170 | return ret; | |
171 | } | |
15b4650e | 172 | SetPageUptodate(page); |
31143d5d DH |
173 | } |
174 | ||
175 | try_again: | |
31143d5d DH |
176 | spin_lock(&vnode->writeback_lock); |
177 | ||
178 | /* see if this page is already pending a writeback under a suitable key | |
179 | * - if so we can just join onto that one */ | |
180 | wb = (struct afs_writeback *) page_private(page); | |
181 | if (wb) { | |
182 | if (wb->key == key && wb->state == AFS_WBACK_PENDING) | |
183 | goto subsume_in_current_wb; | |
184 | goto flush_conflicting_wb; | |
185 | } | |
186 | ||
187 | if (index > 0) { | |
188 | /* see if we can find an already pending writeback that we can | |
189 | * append this page to */ | |
190 | list_for_each_entry(wb, &vnode->writebacks, link) { | |
191 | if (wb->last == index - 1 && wb->key == key && | |
192 | wb->state == AFS_WBACK_PENDING) | |
193 | goto append_to_previous_wb; | |
194 | } | |
195 | } | |
196 | ||
197 | list_add_tail(&candidate->link, &vnode->writebacks); | |
198 | candidate->key = key_get(key); | |
199 | spin_unlock(&vnode->writeback_lock); | |
200 | SetPagePrivate(page); | |
201 | set_page_private(page, (unsigned long) candidate); | |
202 | _leave(" = 0 [new]"); | |
203 | return 0; | |
204 | ||
205 | subsume_in_current_wb: | |
206 | _debug("subsume"); | |
207 | ASSERTRANGE(wb->first, <=, index, <=, wb->last); | |
15b4650e NP |
208 | if (index == wb->first && from < wb->offset_first) |
209 | wb->offset_first = from; | |
31143d5d DH |
210 | if (index == wb->last && to > wb->to_last) |
211 | wb->to_last = to; | |
212 | spin_unlock(&vnode->writeback_lock); | |
213 | kfree(candidate); | |
214 | _leave(" = 0 [sub]"); | |
215 | return 0; | |
216 | ||
217 | append_to_previous_wb: | |
218 | _debug("append into %lx-%lx", wb->first, wb->last); | |
219 | wb->usage++; | |
220 | wb->last++; | |
221 | wb->to_last = to; | |
222 | spin_unlock(&vnode->writeback_lock); | |
223 | SetPagePrivate(page); | |
224 | set_page_private(page, (unsigned long) wb); | |
225 | kfree(candidate); | |
226 | _leave(" = 0 [app]"); | |
227 | return 0; | |
228 | ||
229 | /* the page is currently bound to another context, so if it's dirty we | |
230 | * need to flush it before we can use the new context */ | |
231 | flush_conflicting_wb: | |
232 | _debug("flush conflict"); | |
233 | if (wb->state == AFS_WBACK_PENDING) | |
234 | wb->state = AFS_WBACK_CONFLICTING; | |
235 | spin_unlock(&vnode->writeback_lock); | |
236 | if (PageDirty(page)) { | |
237 | ret = afs_write_back_from_locked_page(wb, page); | |
238 | if (ret < 0) { | |
239 | afs_put_writeback(candidate); | |
240 | _leave(" = %d", ret); | |
241 | return ret; | |
242 | } | |
243 | } | |
244 | ||
245 | /* the page holds a ref on the writeback record */ | |
246 | afs_put_writeback(wb); | |
247 | set_page_private(page, 0); | |
248 | ClearPagePrivate(page); | |
249 | goto try_again; | |
250 | } | |
251 | ||
252 | /* | |
253 | * finalise part of a write to a page | |
254 | */ | |
15b4650e NP |
255 | int afs_write_end(struct file *file, struct address_space *mapping, |
256 | loff_t pos, unsigned len, unsigned copied, | |
257 | struct page *page, void *fsdata) | |
31143d5d | 258 | { |
496ad9aa | 259 | struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
31143d5d DH |
260 | loff_t i_size, maybe_i_size; |
261 | ||
15b4650e NP |
262 | _enter("{%x:%u},{%lx}", |
263 | vnode->fid.vid, vnode->fid.vnode, page->index); | |
31143d5d | 264 | |
15b4650e | 265 | maybe_i_size = pos + copied; |
31143d5d DH |
266 | |
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 | ||
276 | set_page_dirty(page); | |
31143d5d DH |
277 | if (PageDirty(page)) |
278 | _debug("dirtied"); | |
15b4650e | 279 | unlock_page(page); |
09cbfeaf | 280 | put_page(page); |
31143d5d | 281 | |
15b4650e | 282 | return copied; |
31143d5d DH |
283 | } |
284 | ||
285 | /* | |
286 | * kill all the pages in the given range | |
287 | */ | |
288 | static void afs_kill_pages(struct afs_vnode *vnode, bool error, | |
289 | pgoff_t first, pgoff_t last) | |
290 | { | |
291 | struct pagevec pv; | |
292 | unsigned count, loop; | |
293 | ||
294 | _enter("{%x:%u},%lx-%lx", | |
295 | vnode->fid.vid, vnode->fid.vnode, first, last); | |
296 | ||
297 | pagevec_init(&pv, 0); | |
298 | ||
299 | do { | |
300 | _debug("kill %lx-%lx", first, last); | |
301 | ||
302 | count = last - first + 1; | |
303 | if (count > PAGEVEC_SIZE) | |
304 | count = PAGEVEC_SIZE; | |
305 | pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping, | |
306 | first, count, pv.pages); | |
307 | ASSERTCMP(pv.nr, ==, count); | |
308 | ||
309 | for (loop = 0; loop < count; loop++) { | |
310 | ClearPageUptodate(pv.pages[loop]); | |
311 | if (error) | |
312 | SetPageError(pv.pages[loop]); | |
313 | end_page_writeback(pv.pages[loop]); | |
314 | } | |
315 | ||
316 | __pagevec_release(&pv); | |
317 | } while (first < last); | |
318 | ||
319 | _leave(""); | |
320 | } | |
321 | ||
322 | /* | |
323 | * synchronously write back the locked page and any subsequent non-locked dirty | |
324 | * pages also covered by the same writeback record | |
325 | */ | |
326 | static int afs_write_back_from_locked_page(struct afs_writeback *wb, | |
327 | struct page *primary_page) | |
328 | { | |
329 | struct page *pages[8], *page; | |
330 | unsigned long count; | |
331 | unsigned n, offset, to; | |
332 | pgoff_t start, first, last; | |
333 | int loop, ret; | |
334 | ||
335 | _enter(",%lx", primary_page->index); | |
336 | ||
337 | count = 1; | |
338 | if (!clear_page_dirty_for_io(primary_page)) | |
339 | BUG(); | |
340 | if (test_set_page_writeback(primary_page)) | |
341 | BUG(); | |
342 | ||
343 | /* find all consecutive lockable dirty pages, stopping when we find a | |
344 | * page that is not immediately lockable, is not dirty or is missing, | |
345 | * or we reach the end of the range */ | |
346 | start = primary_page->index; | |
347 | if (start >= wb->last) | |
348 | goto no_more; | |
349 | start++; | |
350 | do { | |
351 | _debug("more %lx [%lx]", start, count); | |
352 | n = wb->last - start + 1; | |
353 | if (n > ARRAY_SIZE(pages)) | |
354 | n = ARRAY_SIZE(pages); | |
355 | n = find_get_pages_contig(wb->vnode->vfs_inode.i_mapping, | |
356 | start, n, pages); | |
357 | _debug("fgpc %u", n); | |
358 | if (n == 0) | |
359 | goto no_more; | |
360 | if (pages[0]->index != start) { | |
9d577b6a DH |
361 | do { |
362 | put_page(pages[--n]); | |
363 | } while (n > 0); | |
31143d5d DH |
364 | goto no_more; |
365 | } | |
366 | ||
367 | for (loop = 0; loop < n; loop++) { | |
368 | page = pages[loop]; | |
369 | if (page->index > wb->last) | |
370 | break; | |
529ae9aa | 371 | if (!trylock_page(page)) |
31143d5d DH |
372 | break; |
373 | if (!PageDirty(page) || | |
374 | page_private(page) != (unsigned long) wb) { | |
375 | unlock_page(page); | |
376 | break; | |
377 | } | |
378 | if (!clear_page_dirty_for_io(page)) | |
379 | BUG(); | |
380 | if (test_set_page_writeback(page)) | |
381 | BUG(); | |
382 | unlock_page(page); | |
383 | put_page(page); | |
384 | } | |
385 | count += loop; | |
386 | if (loop < n) { | |
387 | for (; loop < n; loop++) | |
388 | put_page(pages[loop]); | |
389 | goto no_more; | |
390 | } | |
391 | ||
392 | start += loop; | |
393 | } while (start <= wb->last && count < 65536); | |
394 | ||
395 | no_more: | |
396 | /* we now have a contiguous set of dirty pages, each with writeback set | |
397 | * and the dirty mark cleared; the first page is locked and must remain | |
398 | * so, all the rest are unlocked */ | |
399 | first = primary_page->index; | |
400 | last = first + count - 1; | |
401 | ||
402 | offset = (first == wb->first) ? wb->offset_first : 0; | |
403 | to = (last == wb->last) ? wb->to_last : PAGE_SIZE; | |
404 | ||
405 | _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to); | |
406 | ||
407 | ret = afs_vnode_store_data(wb, first, last, offset, to); | |
408 | if (ret < 0) { | |
409 | switch (ret) { | |
410 | case -EDQUOT: | |
411 | case -ENOSPC: | |
5114a97a | 412 | mapping_set_error(wb->vnode->vfs_inode.i_mapping, -ENOSPC); |
31143d5d DH |
413 | break; |
414 | case -EROFS: | |
415 | case -EIO: | |
416 | case -EREMOTEIO: | |
417 | case -EFBIG: | |
418 | case -ENOENT: | |
419 | case -ENOMEDIUM: | |
420 | case -ENXIO: | |
421 | afs_kill_pages(wb->vnode, true, first, last); | |
5114a97a | 422 | mapping_set_error(wb->vnode->vfs_inode.i_mapping, -EIO); |
31143d5d DH |
423 | break; |
424 | case -EACCES: | |
425 | case -EPERM: | |
426 | case -ENOKEY: | |
427 | case -EKEYEXPIRED: | |
428 | case -EKEYREJECTED: | |
429 | case -EKEYREVOKED: | |
430 | afs_kill_pages(wb->vnode, false, first, last); | |
431 | break; | |
432 | default: | |
433 | break; | |
434 | } | |
435 | } else { | |
436 | ret = count; | |
437 | } | |
438 | ||
439 | _leave(" = %d", ret); | |
440 | return ret; | |
441 | } | |
442 | ||
443 | /* | |
444 | * write a page back to the server | |
445 | * - the caller locked the page for us | |
446 | */ | |
447 | int afs_writepage(struct page *page, struct writeback_control *wbc) | |
448 | { | |
31143d5d DH |
449 | struct afs_writeback *wb; |
450 | int ret; | |
451 | ||
452 | _enter("{%lx},", page->index); | |
453 | ||
31143d5d DH |
454 | wb = (struct afs_writeback *) page_private(page); |
455 | ASSERT(wb != NULL); | |
456 | ||
457 | ret = afs_write_back_from_locked_page(wb, page); | |
458 | unlock_page(page); | |
459 | if (ret < 0) { | |
460 | _leave(" = %d", ret); | |
461 | return 0; | |
462 | } | |
463 | ||
464 | wbc->nr_to_write -= ret; | |
31143d5d DH |
465 | |
466 | _leave(" = 0"); | |
467 | return 0; | |
468 | } | |
469 | ||
470 | /* | |
471 | * write a region of pages back to the server | |
472 | */ | |
c1206a2c AB |
473 | static int afs_writepages_region(struct address_space *mapping, |
474 | struct writeback_control *wbc, | |
475 | pgoff_t index, pgoff_t end, pgoff_t *_next) | |
31143d5d | 476 | { |
31143d5d DH |
477 | struct afs_writeback *wb; |
478 | struct page *page; | |
479 | int ret, n; | |
480 | ||
481 | _enter(",,%lx,%lx,", index, end); | |
482 | ||
483 | do { | |
484 | n = find_get_pages_tag(mapping, &index, PAGECACHE_TAG_DIRTY, | |
485 | 1, &page); | |
486 | if (!n) | |
487 | break; | |
488 | ||
489 | _debug("wback %lx", page->index); | |
490 | ||
491 | if (page->index > end) { | |
492 | *_next = index; | |
09cbfeaf | 493 | put_page(page); |
31143d5d DH |
494 | _leave(" = 0 [%lx]", *_next); |
495 | return 0; | |
496 | } | |
497 | ||
498 | /* at this point we hold neither mapping->tree_lock nor lock on | |
499 | * the page itself: the page may be truncated or invalidated | |
500 | * (changing page->mapping to NULL), or even swizzled back from | |
501 | * swapper_space to tmpfs file mapping | |
502 | */ | |
503 | lock_page(page); | |
504 | ||
505 | if (page->mapping != mapping) { | |
506 | unlock_page(page); | |
09cbfeaf | 507 | put_page(page); |
31143d5d DH |
508 | continue; |
509 | } | |
510 | ||
511 | if (wbc->sync_mode != WB_SYNC_NONE) | |
512 | wait_on_page_writeback(page); | |
513 | ||
514 | if (PageWriteback(page) || !PageDirty(page)) { | |
515 | unlock_page(page); | |
516 | continue; | |
517 | } | |
518 | ||
519 | wb = (struct afs_writeback *) page_private(page); | |
520 | ASSERT(wb != NULL); | |
521 | ||
522 | spin_lock(&wb->vnode->writeback_lock); | |
523 | wb->state = AFS_WBACK_WRITING; | |
524 | spin_unlock(&wb->vnode->writeback_lock); | |
525 | ||
526 | ret = afs_write_back_from_locked_page(wb, page); | |
527 | unlock_page(page); | |
09cbfeaf | 528 | put_page(page); |
31143d5d DH |
529 | if (ret < 0) { |
530 | _leave(" = %d", ret); | |
531 | return ret; | |
532 | } | |
533 | ||
534 | wbc->nr_to_write -= ret; | |
535 | ||
31143d5d DH |
536 | cond_resched(); |
537 | } while (index < end && wbc->nr_to_write > 0); | |
538 | ||
539 | *_next = index; | |
540 | _leave(" = 0 [%lx]", *_next); | |
541 | return 0; | |
542 | } | |
543 | ||
544 | /* | |
545 | * write some of the pending data back to the server | |
546 | */ | |
547 | int afs_writepages(struct address_space *mapping, | |
548 | struct writeback_control *wbc) | |
549 | { | |
31143d5d DH |
550 | pgoff_t start, end, next; |
551 | int ret; | |
552 | ||
553 | _enter(""); | |
554 | ||
31143d5d DH |
555 | if (wbc->range_cyclic) { |
556 | start = mapping->writeback_index; | |
557 | end = -1; | |
558 | ret = afs_writepages_region(mapping, wbc, start, end, &next); | |
1b430bee | 559 | if (start > 0 && wbc->nr_to_write > 0 && ret == 0) |
31143d5d DH |
560 | ret = afs_writepages_region(mapping, wbc, 0, start, |
561 | &next); | |
562 | mapping->writeback_index = next; | |
563 | } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { | |
09cbfeaf | 564 | end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT); |
31143d5d DH |
565 | ret = afs_writepages_region(mapping, wbc, 0, end, &next); |
566 | if (wbc->nr_to_write > 0) | |
567 | mapping->writeback_index = next; | |
568 | } else { | |
09cbfeaf KS |
569 | start = wbc->range_start >> PAGE_SHIFT; |
570 | end = wbc->range_end >> PAGE_SHIFT; | |
31143d5d DH |
571 | ret = afs_writepages_region(mapping, wbc, start, end, &next); |
572 | } | |
573 | ||
574 | _leave(" = %d", ret); | |
575 | return ret; | |
576 | } | |
577 | ||
31143d5d DH |
578 | /* |
579 | * completion of write to server | |
580 | */ | |
581 | void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call) | |
582 | { | |
583 | struct afs_writeback *wb = call->wb; | |
584 | struct pagevec pv; | |
585 | unsigned count, loop; | |
586 | pgoff_t first = call->first, last = call->last; | |
587 | bool free_wb; | |
588 | ||
589 | _enter("{%x:%u},{%lx-%lx}", | |
590 | vnode->fid.vid, vnode->fid.vnode, first, last); | |
591 | ||
592 | ASSERT(wb != NULL); | |
593 | ||
594 | pagevec_init(&pv, 0); | |
595 | ||
596 | do { | |
5bbf5d39 | 597 | _debug("done %lx-%lx", first, last); |
31143d5d DH |
598 | |
599 | count = last - first + 1; | |
600 | if (count > PAGEVEC_SIZE) | |
601 | count = PAGEVEC_SIZE; | |
602 | pv.nr = find_get_pages_contig(call->mapping, first, count, | |
603 | pv.pages); | |
604 | ASSERTCMP(pv.nr, ==, count); | |
605 | ||
606 | spin_lock(&vnode->writeback_lock); | |
607 | for (loop = 0; loop < count; loop++) { | |
608 | struct page *page = pv.pages[loop]; | |
609 | end_page_writeback(page); | |
610 | if (page_private(page) == (unsigned long) wb) { | |
611 | set_page_private(page, 0); | |
612 | ClearPagePrivate(page); | |
613 | wb->usage--; | |
614 | } | |
615 | } | |
616 | free_wb = false; | |
617 | if (wb->usage == 0) { | |
618 | afs_unlink_writeback(wb); | |
619 | free_wb = true; | |
620 | } | |
621 | spin_unlock(&vnode->writeback_lock); | |
622 | first += count; | |
623 | if (free_wb) { | |
624 | afs_free_writeback(wb); | |
625 | wb = NULL; | |
626 | } | |
627 | ||
628 | __pagevec_release(&pv); | |
5bbf5d39 | 629 | } while (first <= last); |
31143d5d DH |
630 | |
631 | _leave(""); | |
632 | } | |
633 | ||
634 | /* | |
635 | * write to an AFS file | |
636 | */ | |
50b5551d | 637 | ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) |
31143d5d | 638 | { |
496ad9aa | 639 | struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); |
31143d5d | 640 | ssize_t result; |
50b5551d | 641 | size_t count = iov_iter_count(from); |
31143d5d | 642 | |
50b5551d AV |
643 | _enter("{%x.%u},{%zu},", |
644 | vnode->fid.vid, vnode->fid.vnode, count); | |
31143d5d DH |
645 | |
646 | if (IS_SWAPFILE(&vnode->vfs_inode)) { | |
647 | printk(KERN_INFO | |
648 | "AFS: Attempt to write to active swap file!\n"); | |
649 | return -EBUSY; | |
650 | } | |
651 | ||
652 | if (!count) | |
653 | return 0; | |
654 | ||
50b5551d | 655 | result = generic_file_write_iter(iocb, from); |
31143d5d | 656 | |
31143d5d DH |
657 | _leave(" = %zd", result); |
658 | return result; | |
659 | } | |
660 | ||
661 | /* | |
662 | * flush the vnode to the fileserver | |
663 | */ | |
664 | int afs_writeback_all(struct afs_vnode *vnode) | |
665 | { | |
666 | struct address_space *mapping = vnode->vfs_inode.i_mapping; | |
667 | struct writeback_control wbc = { | |
31143d5d DH |
668 | .sync_mode = WB_SYNC_ALL, |
669 | .nr_to_write = LONG_MAX, | |
31143d5d DH |
670 | .range_cyclic = 1, |
671 | }; | |
672 | int ret; | |
673 | ||
674 | _enter(""); | |
675 | ||
676 | ret = mapping->a_ops->writepages(mapping, &wbc); | |
677 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); | |
678 | ||
679 | _leave(" = %d", ret); | |
680 | return ret; | |
681 | } | |
682 | ||
683 | /* | |
684 | * flush any dirty pages for this process, and check for write errors. | |
685 | * - the return status from this call provides a reliable indication of | |
686 | * whether any write errors occurred for this process. | |
687 | */ | |
02c24a82 | 688 | int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
31143d5d | 689 | { |
3c981bfc | 690 | struct inode *inode = file_inode(file); |
31143d5d | 691 | struct afs_writeback *wb, *xwb; |
3c981bfc | 692 | struct afs_vnode *vnode = AFS_FS_I(inode); |
31143d5d DH |
693 | int ret; |
694 | ||
3c981bfc AV |
695 | _enter("{%x:%u},{n=%pD},%d", |
696 | vnode->fid.vid, vnode->fid.vnode, file, | |
31143d5d DH |
697 | datasync); |
698 | ||
02c24a82 JB |
699 | ret = filemap_write_and_wait_range(inode->i_mapping, start, end); |
700 | if (ret) | |
701 | return ret; | |
5955102c | 702 | inode_lock(inode); |
02c24a82 | 703 | |
31143d5d DH |
704 | /* use a writeback record as a marker in the queue - when this reaches |
705 | * the front of the queue, all the outstanding writes are either | |
706 | * completed or rejected */ | |
707 | wb = kzalloc(sizeof(*wb), GFP_KERNEL); | |
02c24a82 JB |
708 | if (!wb) { |
709 | ret = -ENOMEM; | |
710 | goto out; | |
711 | } | |
31143d5d DH |
712 | wb->vnode = vnode; |
713 | wb->first = 0; | |
714 | wb->last = -1; | |
715 | wb->offset_first = 0; | |
716 | wb->to_last = PAGE_SIZE; | |
717 | wb->usage = 1; | |
718 | wb->state = AFS_WBACK_SYNCING; | |
719 | init_waitqueue_head(&wb->waitq); | |
720 | ||
721 | spin_lock(&vnode->writeback_lock); | |
722 | list_for_each_entry(xwb, &vnode->writebacks, link) { | |
723 | if (xwb->state == AFS_WBACK_PENDING) | |
724 | xwb->state = AFS_WBACK_CONFLICTING; | |
725 | } | |
726 | list_add_tail(&wb->link, &vnode->writebacks); | |
727 | spin_unlock(&vnode->writeback_lock); | |
728 | ||
729 | /* push all the outstanding writebacks to the server */ | |
730 | ret = afs_writeback_all(vnode); | |
731 | if (ret < 0) { | |
732 | afs_put_writeback(wb); | |
733 | _leave(" = %d [wb]", ret); | |
02c24a82 | 734 | goto out; |
31143d5d DH |
735 | } |
736 | ||
737 | /* wait for the preceding writes to actually complete */ | |
738 | ret = wait_event_interruptible(wb->waitq, | |
739 | wb->state == AFS_WBACK_COMPLETE || | |
740 | vnode->writebacks.next == &wb->link); | |
741 | afs_put_writeback(wb); | |
742 | _leave(" = %d", ret); | |
02c24a82 | 743 | out: |
5955102c | 744 | inode_unlock(inode); |
31143d5d DH |
745 | return ret; |
746 | } | |
9b3f26c9 DH |
747 | |
748 | /* | |
749 | * notification that a previously read-only page is about to become writable | |
750 | * - if it returns an error, the caller will deliver a bus error signal | |
751 | */ | |
752 | int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page) | |
753 | { | |
754 | struct afs_vnode *vnode = AFS_FS_I(vma->vm_file->f_mapping->host); | |
755 | ||
756 | _enter("{{%x:%u}},{%lx}", | |
757 | vnode->fid.vid, vnode->fid.vnode, page->index); | |
758 | ||
759 | /* wait for the page to be written to the cache before we allow it to | |
760 | * be modified */ | |
761 | #ifdef CONFIG_AFS_FSCACHE | |
762 | fscache_wait_on_page_write(vnode->cache, page); | |
763 | #endif | |
764 | ||
765 | _leave(" = 0"); | |
766 | return 0; | |
767 | } |