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> | |
a27bb332 | 17 | #include <linux/aio.h> |
31143d5d DH |
18 | #include "internal.h" |
19 | ||
20 | static int afs_write_back_from_locked_page(struct afs_writeback *wb, | |
21 | struct page *page); | |
22 | ||
23 | /* | |
24 | * mark a page as having been made dirty and thus needing writeback | |
25 | */ | |
26 | int afs_set_page_dirty(struct page *page) | |
27 | { | |
28 | _enter(""); | |
29 | return __set_page_dirty_nobuffers(page); | |
30 | } | |
31 | ||
32 | /* | |
33 | * unlink a writeback record because its usage has reached zero | |
34 | * - must be called with the wb->vnode->writeback_lock held | |
35 | */ | |
36 | static void afs_unlink_writeback(struct afs_writeback *wb) | |
37 | { | |
38 | struct afs_writeback *front; | |
39 | struct afs_vnode *vnode = wb->vnode; | |
40 | ||
41 | list_del_init(&wb->link); | |
42 | if (!list_empty(&vnode->writebacks)) { | |
43 | /* if an fsync rises to the front of the queue then wake it | |
44 | * up */ | |
45 | front = list_entry(vnode->writebacks.next, | |
46 | struct afs_writeback, link); | |
47 | if (front->state == AFS_WBACK_SYNCING) { | |
48 | _debug("wake up sync"); | |
49 | front->state = AFS_WBACK_COMPLETE; | |
50 | wake_up(&front->waitq); | |
51 | } | |
52 | } | |
53 | } | |
54 | ||
55 | /* | |
56 | * free a writeback record | |
57 | */ | |
58 | static void afs_free_writeback(struct afs_writeback *wb) | |
59 | { | |
60 | _enter(""); | |
61 | key_put(wb->key); | |
62 | kfree(wb); | |
63 | } | |
64 | ||
65 | /* | |
66 | * dispose of a reference to a writeback record | |
67 | */ | |
68 | void afs_put_writeback(struct afs_writeback *wb) | |
69 | { | |
70 | struct afs_vnode *vnode = wb->vnode; | |
71 | ||
72 | _enter("{%d}", wb->usage); | |
73 | ||
74 | spin_lock(&vnode->writeback_lock); | |
75 | if (--wb->usage == 0) | |
76 | afs_unlink_writeback(wb); | |
77 | else | |
78 | wb = NULL; | |
79 | spin_unlock(&vnode->writeback_lock); | |
80 | if (wb) | |
81 | afs_free_writeback(wb); | |
82 | } | |
83 | ||
84 | /* | |
85 | * partly or wholly fill a page that's under preparation for writing | |
86 | */ | |
87 | static int afs_fill_page(struct afs_vnode *vnode, struct key *key, | |
5e7f2337 | 88 | loff_t pos, struct page *page) |
31143d5d | 89 | { |
15b4650e | 90 | loff_t i_size; |
31143d5d | 91 | int ret; |
5e7f2337 | 92 | int len; |
31143d5d | 93 | |
5e7f2337 | 94 | _enter(",,%llu", (unsigned long long)pos); |
31143d5d | 95 | |
15b4650e | 96 | i_size = i_size_read(&vnode->vfs_inode); |
5e7f2337 AB |
97 | if (pos + PAGE_CACHE_SIZE > i_size) |
98 | len = i_size - pos; | |
15b4650e | 99 | else |
5e7f2337 | 100 | len = PAGE_CACHE_SIZE; |
15b4650e | 101 | |
5e7f2337 | 102 | ret = afs_vnode_fetch_data(vnode, key, pos, len, page); |
31143d5d DH |
103 | if (ret < 0) { |
104 | if (ret == -ENOENT) { | |
105 | _debug("got NOENT from server" | |
106 | " - marking file deleted and stale"); | |
107 | set_bit(AFS_VNODE_DELETED, &vnode->flags); | |
108 | ret = -ESTALE; | |
109 | } | |
110 | } | |
111 | ||
112 | _leave(" = %d", ret); | |
113 | return ret; | |
114 | } | |
115 | ||
31143d5d DH |
116 | /* |
117 | * prepare to perform part of a write to a page | |
31143d5d | 118 | */ |
15b4650e NP |
119 | int afs_write_begin(struct file *file, struct address_space *mapping, |
120 | loff_t pos, unsigned len, unsigned flags, | |
121 | struct page **pagep, void **fsdata) | |
31143d5d DH |
122 | { |
123 | struct afs_writeback *candidate, *wb; | |
496ad9aa | 124 | struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
15b4650e | 125 | struct page *page; |
31143d5d | 126 | struct key *key = file->private_data; |
15b4650e NP |
127 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); |
128 | unsigned to = from + len; | |
129 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
31143d5d DH |
130 | int ret; |
131 | ||
132 | _enter("{%x:%u},{%lx},%u,%u", | |
15b4650e | 133 | vnode->fid.vid, vnode->fid.vnode, index, from, to); |
31143d5d DH |
134 | |
135 | candidate = kzalloc(sizeof(*candidate), GFP_KERNEL); | |
136 | if (!candidate) | |
137 | return -ENOMEM; | |
138 | candidate->vnode = vnode; | |
15b4650e NP |
139 | candidate->first = candidate->last = index; |
140 | candidate->offset_first = from; | |
31143d5d | 141 | candidate->to_last = to; |
f129ccc9 | 142 | INIT_LIST_HEAD(&candidate->link); |
31143d5d DH |
143 | candidate->usage = 1; |
144 | candidate->state = AFS_WBACK_PENDING; | |
145 | init_waitqueue_head(&candidate->waitq); | |
146 | ||
54566b2c | 147 | page = grab_cache_page_write_begin(mapping, index, flags); |
15b4650e NP |
148 | if (!page) { |
149 | kfree(candidate); | |
150 | return -ENOMEM; | |
151 | } | |
152 | *pagep = page; | |
153 | /* page won't leak in error case: it eventually gets cleaned off LRU */ | |
154 | ||
5e7f2337 AB |
155 | if (!PageUptodate(page) && len != PAGE_CACHE_SIZE) { |
156 | ret = afs_fill_page(vnode, key, index << PAGE_CACHE_SHIFT, page); | |
31143d5d DH |
157 | if (ret < 0) { |
158 | kfree(candidate); | |
159 | _leave(" = %d [prep]", ret); | |
160 | return ret; | |
161 | } | |
15b4650e | 162 | SetPageUptodate(page); |
31143d5d DH |
163 | } |
164 | ||
165 | try_again: | |
31143d5d DH |
166 | spin_lock(&vnode->writeback_lock); |
167 | ||
168 | /* see if this page is already pending a writeback under a suitable key | |
169 | * - if so we can just join onto that one */ | |
170 | wb = (struct afs_writeback *) page_private(page); | |
171 | if (wb) { | |
172 | if (wb->key == key && wb->state == AFS_WBACK_PENDING) | |
173 | goto subsume_in_current_wb; | |
174 | goto flush_conflicting_wb; | |
175 | } | |
176 | ||
177 | if (index > 0) { | |
178 | /* see if we can find an already pending writeback that we can | |
179 | * append this page to */ | |
180 | list_for_each_entry(wb, &vnode->writebacks, link) { | |
181 | if (wb->last == index - 1 && wb->key == key && | |
182 | wb->state == AFS_WBACK_PENDING) | |
183 | goto append_to_previous_wb; | |
184 | } | |
185 | } | |
186 | ||
187 | list_add_tail(&candidate->link, &vnode->writebacks); | |
188 | candidate->key = key_get(key); | |
189 | spin_unlock(&vnode->writeback_lock); | |
190 | SetPagePrivate(page); | |
191 | set_page_private(page, (unsigned long) candidate); | |
192 | _leave(" = 0 [new]"); | |
193 | return 0; | |
194 | ||
195 | subsume_in_current_wb: | |
196 | _debug("subsume"); | |
197 | ASSERTRANGE(wb->first, <=, index, <=, wb->last); | |
15b4650e NP |
198 | if (index == wb->first && from < wb->offset_first) |
199 | wb->offset_first = from; | |
31143d5d DH |
200 | if (index == wb->last && to > wb->to_last) |
201 | wb->to_last = to; | |
202 | spin_unlock(&vnode->writeback_lock); | |
203 | kfree(candidate); | |
204 | _leave(" = 0 [sub]"); | |
205 | return 0; | |
206 | ||
207 | append_to_previous_wb: | |
208 | _debug("append into %lx-%lx", wb->first, wb->last); | |
209 | wb->usage++; | |
210 | wb->last++; | |
211 | wb->to_last = to; | |
212 | spin_unlock(&vnode->writeback_lock); | |
213 | SetPagePrivate(page); | |
214 | set_page_private(page, (unsigned long) wb); | |
215 | kfree(candidate); | |
216 | _leave(" = 0 [app]"); | |
217 | return 0; | |
218 | ||
219 | /* the page is currently bound to another context, so if it's dirty we | |
220 | * need to flush it before we can use the new context */ | |
221 | flush_conflicting_wb: | |
222 | _debug("flush conflict"); | |
223 | if (wb->state == AFS_WBACK_PENDING) | |
224 | wb->state = AFS_WBACK_CONFLICTING; | |
225 | spin_unlock(&vnode->writeback_lock); | |
226 | if (PageDirty(page)) { | |
227 | ret = afs_write_back_from_locked_page(wb, page); | |
228 | if (ret < 0) { | |
229 | afs_put_writeback(candidate); | |
230 | _leave(" = %d", ret); | |
231 | return ret; | |
232 | } | |
233 | } | |
234 | ||
235 | /* the page holds a ref on the writeback record */ | |
236 | afs_put_writeback(wb); | |
237 | set_page_private(page, 0); | |
238 | ClearPagePrivate(page); | |
239 | goto try_again; | |
240 | } | |
241 | ||
242 | /* | |
243 | * finalise part of a write to a page | |
244 | */ | |
15b4650e NP |
245 | int afs_write_end(struct file *file, struct address_space *mapping, |
246 | loff_t pos, unsigned len, unsigned copied, | |
247 | struct page *page, void *fsdata) | |
31143d5d | 248 | { |
496ad9aa | 249 | struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
31143d5d DH |
250 | loff_t i_size, maybe_i_size; |
251 | ||
15b4650e NP |
252 | _enter("{%x:%u},{%lx}", |
253 | vnode->fid.vid, vnode->fid.vnode, page->index); | |
31143d5d | 254 | |
15b4650e | 255 | maybe_i_size = pos + copied; |
31143d5d DH |
256 | |
257 | i_size = i_size_read(&vnode->vfs_inode); | |
258 | if (maybe_i_size > i_size) { | |
259 | spin_lock(&vnode->writeback_lock); | |
260 | i_size = i_size_read(&vnode->vfs_inode); | |
261 | if (maybe_i_size > i_size) | |
262 | i_size_write(&vnode->vfs_inode, maybe_i_size); | |
263 | spin_unlock(&vnode->writeback_lock); | |
264 | } | |
265 | ||
266 | set_page_dirty(page); | |
31143d5d DH |
267 | if (PageDirty(page)) |
268 | _debug("dirtied"); | |
15b4650e NP |
269 | unlock_page(page); |
270 | page_cache_release(page); | |
31143d5d | 271 | |
15b4650e | 272 | return copied; |
31143d5d DH |
273 | } |
274 | ||
275 | /* | |
276 | * kill all the pages in the given range | |
277 | */ | |
278 | static void afs_kill_pages(struct afs_vnode *vnode, bool error, | |
279 | pgoff_t first, pgoff_t last) | |
280 | { | |
281 | struct pagevec pv; | |
282 | unsigned count, loop; | |
283 | ||
284 | _enter("{%x:%u},%lx-%lx", | |
285 | vnode->fid.vid, vnode->fid.vnode, first, last); | |
286 | ||
287 | pagevec_init(&pv, 0); | |
288 | ||
289 | do { | |
290 | _debug("kill %lx-%lx", first, last); | |
291 | ||
292 | count = last - first + 1; | |
293 | if (count > PAGEVEC_SIZE) | |
294 | count = PAGEVEC_SIZE; | |
295 | pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping, | |
296 | first, count, pv.pages); | |
297 | ASSERTCMP(pv.nr, ==, count); | |
298 | ||
299 | for (loop = 0; loop < count; loop++) { | |
300 | ClearPageUptodate(pv.pages[loop]); | |
301 | if (error) | |
302 | SetPageError(pv.pages[loop]); | |
303 | end_page_writeback(pv.pages[loop]); | |
304 | } | |
305 | ||
306 | __pagevec_release(&pv); | |
307 | } while (first < last); | |
308 | ||
309 | _leave(""); | |
310 | } | |
311 | ||
312 | /* | |
313 | * synchronously write back the locked page and any subsequent non-locked dirty | |
314 | * pages also covered by the same writeback record | |
315 | */ | |
316 | static int afs_write_back_from_locked_page(struct afs_writeback *wb, | |
317 | struct page *primary_page) | |
318 | { | |
319 | struct page *pages[8], *page; | |
320 | unsigned long count; | |
321 | unsigned n, offset, to; | |
322 | pgoff_t start, first, last; | |
323 | int loop, ret; | |
324 | ||
325 | _enter(",%lx", primary_page->index); | |
326 | ||
327 | count = 1; | |
328 | if (!clear_page_dirty_for_io(primary_page)) | |
329 | BUG(); | |
330 | if (test_set_page_writeback(primary_page)) | |
331 | BUG(); | |
332 | ||
333 | /* find all consecutive lockable dirty pages, stopping when we find a | |
334 | * page that is not immediately lockable, is not dirty or is missing, | |
335 | * or we reach the end of the range */ | |
336 | start = primary_page->index; | |
337 | if (start >= wb->last) | |
338 | goto no_more; | |
339 | start++; | |
340 | do { | |
341 | _debug("more %lx [%lx]", start, count); | |
342 | n = wb->last - start + 1; | |
343 | if (n > ARRAY_SIZE(pages)) | |
344 | n = ARRAY_SIZE(pages); | |
345 | n = find_get_pages_contig(wb->vnode->vfs_inode.i_mapping, | |
346 | start, n, pages); | |
347 | _debug("fgpc %u", n); | |
348 | if (n == 0) | |
349 | goto no_more; | |
350 | if (pages[0]->index != start) { | |
9d577b6a DH |
351 | do { |
352 | put_page(pages[--n]); | |
353 | } while (n > 0); | |
31143d5d DH |
354 | goto no_more; |
355 | } | |
356 | ||
357 | for (loop = 0; loop < n; loop++) { | |
358 | page = pages[loop]; | |
359 | if (page->index > wb->last) | |
360 | break; | |
529ae9aa | 361 | if (!trylock_page(page)) |
31143d5d DH |
362 | break; |
363 | if (!PageDirty(page) || | |
364 | page_private(page) != (unsigned long) wb) { | |
365 | unlock_page(page); | |
366 | break; | |
367 | } | |
368 | if (!clear_page_dirty_for_io(page)) | |
369 | BUG(); | |
370 | if (test_set_page_writeback(page)) | |
371 | BUG(); | |
372 | unlock_page(page); | |
373 | put_page(page); | |
374 | } | |
375 | count += loop; | |
376 | if (loop < n) { | |
377 | for (; loop < n; loop++) | |
378 | put_page(pages[loop]); | |
379 | goto no_more; | |
380 | } | |
381 | ||
382 | start += loop; | |
383 | } while (start <= wb->last && count < 65536); | |
384 | ||
385 | no_more: | |
386 | /* we now have a contiguous set of dirty pages, each with writeback set | |
387 | * and the dirty mark cleared; the first page is locked and must remain | |
388 | * so, all the rest are unlocked */ | |
389 | first = primary_page->index; | |
390 | last = first + count - 1; | |
391 | ||
392 | offset = (first == wb->first) ? wb->offset_first : 0; | |
393 | to = (last == wb->last) ? wb->to_last : PAGE_SIZE; | |
394 | ||
395 | _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to); | |
396 | ||
397 | ret = afs_vnode_store_data(wb, first, last, offset, to); | |
398 | if (ret < 0) { | |
399 | switch (ret) { | |
400 | case -EDQUOT: | |
401 | case -ENOSPC: | |
402 | set_bit(AS_ENOSPC, | |
403 | &wb->vnode->vfs_inode.i_mapping->flags); | |
404 | break; | |
405 | case -EROFS: | |
406 | case -EIO: | |
407 | case -EREMOTEIO: | |
408 | case -EFBIG: | |
409 | case -ENOENT: | |
410 | case -ENOMEDIUM: | |
411 | case -ENXIO: | |
412 | afs_kill_pages(wb->vnode, true, first, last); | |
413 | set_bit(AS_EIO, &wb->vnode->vfs_inode.i_mapping->flags); | |
414 | break; | |
415 | case -EACCES: | |
416 | case -EPERM: | |
417 | case -ENOKEY: | |
418 | case -EKEYEXPIRED: | |
419 | case -EKEYREJECTED: | |
420 | case -EKEYREVOKED: | |
421 | afs_kill_pages(wb->vnode, false, first, last); | |
422 | break; | |
423 | default: | |
424 | break; | |
425 | } | |
426 | } else { | |
427 | ret = count; | |
428 | } | |
429 | ||
430 | _leave(" = %d", ret); | |
431 | return ret; | |
432 | } | |
433 | ||
434 | /* | |
435 | * write a page back to the server | |
436 | * - the caller locked the page for us | |
437 | */ | |
438 | int afs_writepage(struct page *page, struct writeback_control *wbc) | |
439 | { | |
31143d5d DH |
440 | struct afs_writeback *wb; |
441 | int ret; | |
442 | ||
443 | _enter("{%lx},", page->index); | |
444 | ||
31143d5d DH |
445 | wb = (struct afs_writeback *) page_private(page); |
446 | ASSERT(wb != NULL); | |
447 | ||
448 | ret = afs_write_back_from_locked_page(wb, page); | |
449 | unlock_page(page); | |
450 | if (ret < 0) { | |
451 | _leave(" = %d", ret); | |
452 | return 0; | |
453 | } | |
454 | ||
455 | wbc->nr_to_write -= ret; | |
31143d5d DH |
456 | |
457 | _leave(" = 0"); | |
458 | return 0; | |
459 | } | |
460 | ||
461 | /* | |
462 | * write a region of pages back to the server | |
463 | */ | |
c1206a2c AB |
464 | static int afs_writepages_region(struct address_space *mapping, |
465 | struct writeback_control *wbc, | |
466 | pgoff_t index, pgoff_t end, pgoff_t *_next) | |
31143d5d | 467 | { |
31143d5d DH |
468 | struct afs_writeback *wb; |
469 | struct page *page; | |
470 | int ret, n; | |
471 | ||
472 | _enter(",,%lx,%lx,", index, end); | |
473 | ||
474 | do { | |
475 | n = find_get_pages_tag(mapping, &index, PAGECACHE_TAG_DIRTY, | |
476 | 1, &page); | |
477 | if (!n) | |
478 | break; | |
479 | ||
480 | _debug("wback %lx", page->index); | |
481 | ||
482 | if (page->index > end) { | |
483 | *_next = index; | |
484 | page_cache_release(page); | |
485 | _leave(" = 0 [%lx]", *_next); | |
486 | return 0; | |
487 | } | |
488 | ||
489 | /* at this point we hold neither mapping->tree_lock nor lock on | |
490 | * the page itself: the page may be truncated or invalidated | |
491 | * (changing page->mapping to NULL), or even swizzled back from | |
492 | * swapper_space to tmpfs file mapping | |
493 | */ | |
494 | lock_page(page); | |
495 | ||
496 | if (page->mapping != mapping) { | |
497 | unlock_page(page); | |
498 | page_cache_release(page); | |
499 | continue; | |
500 | } | |
501 | ||
502 | if (wbc->sync_mode != WB_SYNC_NONE) | |
503 | wait_on_page_writeback(page); | |
504 | ||
505 | if (PageWriteback(page) || !PageDirty(page)) { | |
506 | unlock_page(page); | |
507 | continue; | |
508 | } | |
509 | ||
510 | wb = (struct afs_writeback *) page_private(page); | |
511 | ASSERT(wb != NULL); | |
512 | ||
513 | spin_lock(&wb->vnode->writeback_lock); | |
514 | wb->state = AFS_WBACK_WRITING; | |
515 | spin_unlock(&wb->vnode->writeback_lock); | |
516 | ||
517 | ret = afs_write_back_from_locked_page(wb, page); | |
518 | unlock_page(page); | |
519 | page_cache_release(page); | |
520 | if (ret < 0) { | |
521 | _leave(" = %d", ret); | |
522 | return ret; | |
523 | } | |
524 | ||
525 | wbc->nr_to_write -= ret; | |
526 | ||
31143d5d DH |
527 | cond_resched(); |
528 | } while (index < end && wbc->nr_to_write > 0); | |
529 | ||
530 | *_next = index; | |
531 | _leave(" = 0 [%lx]", *_next); | |
532 | return 0; | |
533 | } | |
534 | ||
535 | /* | |
536 | * write some of the pending data back to the server | |
537 | */ | |
538 | int afs_writepages(struct address_space *mapping, | |
539 | struct writeback_control *wbc) | |
540 | { | |
31143d5d DH |
541 | pgoff_t start, end, next; |
542 | int ret; | |
543 | ||
544 | _enter(""); | |
545 | ||
31143d5d DH |
546 | if (wbc->range_cyclic) { |
547 | start = mapping->writeback_index; | |
548 | end = -1; | |
549 | ret = afs_writepages_region(mapping, wbc, start, end, &next); | |
1b430bee | 550 | if (start > 0 && wbc->nr_to_write > 0 && ret == 0) |
31143d5d DH |
551 | ret = afs_writepages_region(mapping, wbc, 0, start, |
552 | &next); | |
553 | mapping->writeback_index = next; | |
554 | } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { | |
555 | end = (pgoff_t)(LLONG_MAX >> PAGE_CACHE_SHIFT); | |
556 | ret = afs_writepages_region(mapping, wbc, 0, end, &next); | |
557 | if (wbc->nr_to_write > 0) | |
558 | mapping->writeback_index = next; | |
559 | } else { | |
560 | start = wbc->range_start >> PAGE_CACHE_SHIFT; | |
561 | end = wbc->range_end >> PAGE_CACHE_SHIFT; | |
562 | ret = afs_writepages_region(mapping, wbc, start, end, &next); | |
563 | } | |
564 | ||
565 | _leave(" = %d", ret); | |
566 | return ret; | |
567 | } | |
568 | ||
31143d5d DH |
569 | /* |
570 | * completion of write to server | |
571 | */ | |
572 | void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call) | |
573 | { | |
574 | struct afs_writeback *wb = call->wb; | |
575 | struct pagevec pv; | |
576 | unsigned count, loop; | |
577 | pgoff_t first = call->first, last = call->last; | |
578 | bool free_wb; | |
579 | ||
580 | _enter("{%x:%u},{%lx-%lx}", | |
581 | vnode->fid.vid, vnode->fid.vnode, first, last); | |
582 | ||
583 | ASSERT(wb != NULL); | |
584 | ||
585 | pagevec_init(&pv, 0); | |
586 | ||
587 | do { | |
5bbf5d39 | 588 | _debug("done %lx-%lx", first, last); |
31143d5d DH |
589 | |
590 | count = last - first + 1; | |
591 | if (count > PAGEVEC_SIZE) | |
592 | count = PAGEVEC_SIZE; | |
593 | pv.nr = find_get_pages_contig(call->mapping, first, count, | |
594 | pv.pages); | |
595 | ASSERTCMP(pv.nr, ==, count); | |
596 | ||
597 | spin_lock(&vnode->writeback_lock); | |
598 | for (loop = 0; loop < count; loop++) { | |
599 | struct page *page = pv.pages[loop]; | |
600 | end_page_writeback(page); | |
601 | if (page_private(page) == (unsigned long) wb) { | |
602 | set_page_private(page, 0); | |
603 | ClearPagePrivate(page); | |
604 | wb->usage--; | |
605 | } | |
606 | } | |
607 | free_wb = false; | |
608 | if (wb->usage == 0) { | |
609 | afs_unlink_writeback(wb); | |
610 | free_wb = true; | |
611 | } | |
612 | spin_unlock(&vnode->writeback_lock); | |
613 | first += count; | |
614 | if (free_wb) { | |
615 | afs_free_writeback(wb); | |
616 | wb = NULL; | |
617 | } | |
618 | ||
619 | __pagevec_release(&pv); | |
5bbf5d39 | 620 | } while (first <= last); |
31143d5d DH |
621 | |
622 | _leave(""); | |
623 | } | |
624 | ||
625 | /* | |
626 | * write to an AFS file | |
627 | */ | |
50b5551d | 628 | ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) |
31143d5d | 629 | { |
496ad9aa | 630 | struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); |
31143d5d | 631 | ssize_t result; |
50b5551d | 632 | size_t count = iov_iter_count(from); |
31143d5d | 633 | |
50b5551d AV |
634 | _enter("{%x.%u},{%zu},", |
635 | vnode->fid.vid, vnode->fid.vnode, count); | |
31143d5d DH |
636 | |
637 | if (IS_SWAPFILE(&vnode->vfs_inode)) { | |
638 | printk(KERN_INFO | |
639 | "AFS: Attempt to write to active swap file!\n"); | |
640 | return -EBUSY; | |
641 | } | |
642 | ||
643 | if (!count) | |
644 | return 0; | |
645 | ||
50b5551d | 646 | result = generic_file_write_iter(iocb, from); |
31143d5d DH |
647 | if (IS_ERR_VALUE(result)) { |
648 | _leave(" = %zd", result); | |
649 | return result; | |
650 | } | |
651 | ||
31143d5d DH |
652 | _leave(" = %zd", result); |
653 | return result; | |
654 | } | |
655 | ||
656 | /* | |
657 | * flush the vnode to the fileserver | |
658 | */ | |
659 | int afs_writeback_all(struct afs_vnode *vnode) | |
660 | { | |
661 | struct address_space *mapping = vnode->vfs_inode.i_mapping; | |
662 | struct writeback_control wbc = { | |
31143d5d DH |
663 | .sync_mode = WB_SYNC_ALL, |
664 | .nr_to_write = LONG_MAX, | |
31143d5d DH |
665 | .range_cyclic = 1, |
666 | }; | |
667 | int ret; | |
668 | ||
669 | _enter(""); | |
670 | ||
671 | ret = mapping->a_ops->writepages(mapping, &wbc); | |
672 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); | |
673 | ||
674 | _leave(" = %d", ret); | |
675 | return ret; | |
676 | } | |
677 | ||
678 | /* | |
679 | * flush any dirty pages for this process, and check for write errors. | |
680 | * - the return status from this call provides a reliable indication of | |
681 | * whether any write errors occurred for this process. | |
682 | */ | |
02c24a82 | 683 | int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
31143d5d | 684 | { |
7ea80859 | 685 | struct dentry *dentry = file->f_path.dentry; |
02c24a82 | 686 | struct inode *inode = file->f_mapping->host; |
31143d5d DH |
687 | struct afs_writeback *wb, *xwb; |
688 | struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode); | |
689 | int ret; | |
690 | ||
a455589f AV |
691 | _enter("{%x:%u},{n=%pd},%d", |
692 | vnode->fid.vid, vnode->fid.vnode, dentry, | |
31143d5d DH |
693 | datasync); |
694 | ||
02c24a82 JB |
695 | ret = filemap_write_and_wait_range(inode->i_mapping, start, end); |
696 | if (ret) | |
697 | return ret; | |
698 | mutex_lock(&inode->i_mutex); | |
699 | ||
31143d5d DH |
700 | /* use a writeback record as a marker in the queue - when this reaches |
701 | * the front of the queue, all the outstanding writes are either | |
702 | * completed or rejected */ | |
703 | wb = kzalloc(sizeof(*wb), GFP_KERNEL); | |
02c24a82 JB |
704 | if (!wb) { |
705 | ret = -ENOMEM; | |
706 | goto out; | |
707 | } | |
31143d5d DH |
708 | wb->vnode = vnode; |
709 | wb->first = 0; | |
710 | wb->last = -1; | |
711 | wb->offset_first = 0; | |
712 | wb->to_last = PAGE_SIZE; | |
713 | wb->usage = 1; | |
714 | wb->state = AFS_WBACK_SYNCING; | |
715 | init_waitqueue_head(&wb->waitq); | |
716 | ||
717 | spin_lock(&vnode->writeback_lock); | |
718 | list_for_each_entry(xwb, &vnode->writebacks, link) { | |
719 | if (xwb->state == AFS_WBACK_PENDING) | |
720 | xwb->state = AFS_WBACK_CONFLICTING; | |
721 | } | |
722 | list_add_tail(&wb->link, &vnode->writebacks); | |
723 | spin_unlock(&vnode->writeback_lock); | |
724 | ||
725 | /* push all the outstanding writebacks to the server */ | |
726 | ret = afs_writeback_all(vnode); | |
727 | if (ret < 0) { | |
728 | afs_put_writeback(wb); | |
729 | _leave(" = %d [wb]", ret); | |
02c24a82 | 730 | goto out; |
31143d5d DH |
731 | } |
732 | ||
733 | /* wait for the preceding writes to actually complete */ | |
734 | ret = wait_event_interruptible(wb->waitq, | |
735 | wb->state == AFS_WBACK_COMPLETE || | |
736 | vnode->writebacks.next == &wb->link); | |
737 | afs_put_writeback(wb); | |
738 | _leave(" = %d", ret); | |
02c24a82 JB |
739 | out: |
740 | mutex_unlock(&inode->i_mutex); | |
31143d5d DH |
741 | return ret; |
742 | } | |
9b3f26c9 DH |
743 | |
744 | /* | |
745 | * notification that a previously read-only page is about to become writable | |
746 | * - if it returns an error, the caller will deliver a bus error signal | |
747 | */ | |
748 | int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page) | |
749 | { | |
750 | struct afs_vnode *vnode = AFS_FS_I(vma->vm_file->f_mapping->host); | |
751 | ||
752 | _enter("{{%x:%u}},{%lx}", | |
753 | vnode->fid.vid, vnode->fid.vnode, page->index); | |
754 | ||
755 | /* wait for the page to be written to the cache before we allow it to | |
756 | * be modified */ | |
757 | #ifdef CONFIG_AFS_FSCACHE | |
758 | fscache_wait_on_page_write(vnode->cache, page); | |
759 | #endif | |
760 | ||
761 | _leave(" = 0"); | |
762 | return 0; | |
763 | } |