Commit | Line | Data |
---|---|---|
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 | } | |
15b4650e | 157 | |
09cbfeaf | 158 | if (!PageUptodate(page) && len != PAGE_SIZE) { |
e8e581a8 | 159 | ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page); |
31143d5d | 160 | if (ret < 0) { |
6d06b0d2 DH |
161 | unlock_page(page); |
162 | put_page(page); | |
31143d5d DH |
163 | kfree(candidate); |
164 | _leave(" = %d [prep]", ret); | |
165 | return ret; | |
166 | } | |
15b4650e | 167 | SetPageUptodate(page); |
31143d5d DH |
168 | } |
169 | ||
6d06b0d2 DH |
170 | /* page won't leak in error case: it eventually gets cleaned off LRU */ |
171 | *pagep = page; | |
172 | ||
31143d5d | 173 | try_again: |
31143d5d DH |
174 | spin_lock(&vnode->writeback_lock); |
175 | ||
176 | /* see if this page is already pending a writeback under a suitable key | |
177 | * - if so we can just join onto that one */ | |
178 | wb = (struct afs_writeback *) page_private(page); | |
179 | if (wb) { | |
180 | if (wb->key == key && wb->state == AFS_WBACK_PENDING) | |
181 | goto subsume_in_current_wb; | |
182 | goto flush_conflicting_wb; | |
183 | } | |
184 | ||
185 | if (index > 0) { | |
186 | /* see if we can find an already pending writeback that we can | |
187 | * append this page to */ | |
188 | list_for_each_entry(wb, &vnode->writebacks, link) { | |
189 | if (wb->last == index - 1 && wb->key == key && | |
190 | wb->state == AFS_WBACK_PENDING) | |
191 | goto append_to_previous_wb; | |
192 | } | |
193 | } | |
194 | ||
195 | list_add_tail(&candidate->link, &vnode->writebacks); | |
196 | candidate->key = key_get(key); | |
197 | spin_unlock(&vnode->writeback_lock); | |
198 | SetPagePrivate(page); | |
199 | set_page_private(page, (unsigned long) candidate); | |
200 | _leave(" = 0 [new]"); | |
201 | return 0; | |
202 | ||
203 | subsume_in_current_wb: | |
204 | _debug("subsume"); | |
205 | ASSERTRANGE(wb->first, <=, index, <=, wb->last); | |
15b4650e NP |
206 | if (index == wb->first && from < wb->offset_first) |
207 | wb->offset_first = from; | |
31143d5d DH |
208 | if (index == wb->last && to > wb->to_last) |
209 | wb->to_last = to; | |
210 | spin_unlock(&vnode->writeback_lock); | |
211 | kfree(candidate); | |
212 | _leave(" = 0 [sub]"); | |
213 | return 0; | |
214 | ||
215 | append_to_previous_wb: | |
216 | _debug("append into %lx-%lx", wb->first, wb->last); | |
217 | wb->usage++; | |
218 | wb->last++; | |
219 | wb->to_last = to; | |
220 | spin_unlock(&vnode->writeback_lock); | |
221 | SetPagePrivate(page); | |
222 | set_page_private(page, (unsigned long) wb); | |
223 | kfree(candidate); | |
224 | _leave(" = 0 [app]"); | |
225 | return 0; | |
226 | ||
227 | /* the page is currently bound to another context, so if it's dirty we | |
228 | * need to flush it before we can use the new context */ | |
229 | flush_conflicting_wb: | |
230 | _debug("flush conflict"); | |
231 | if (wb->state == AFS_WBACK_PENDING) | |
232 | wb->state = AFS_WBACK_CONFLICTING; | |
233 | spin_unlock(&vnode->writeback_lock); | |
65a15109 | 234 | if (clear_page_dirty_for_io(page)) { |
31143d5d DH |
235 | ret = afs_write_back_from_locked_page(wb, page); |
236 | if (ret < 0) { | |
237 | afs_put_writeback(candidate); | |
238 | _leave(" = %d", ret); | |
239 | return ret; | |
240 | } | |
241 | } | |
242 | ||
243 | /* the page holds a ref on the writeback record */ | |
244 | afs_put_writeback(wb); | |
245 | set_page_private(page, 0); | |
246 | ClearPagePrivate(page); | |
247 | goto try_again; | |
248 | } | |
249 | ||
250 | /* | |
251 | * finalise part of a write to a page | |
252 | */ | |
15b4650e NP |
253 | int afs_write_end(struct file *file, struct address_space *mapping, |
254 | loff_t pos, unsigned len, unsigned copied, | |
255 | struct page *page, void *fsdata) | |
31143d5d | 256 | { |
496ad9aa | 257 | struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
e8e581a8 | 258 | struct key *key = file->private_data; |
31143d5d | 259 | loff_t i_size, maybe_i_size; |
e8e581a8 | 260 | int ret; |
31143d5d | 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 | ||
e8e581a8 DH |
276 | if (!PageUptodate(page)) { |
277 | if (copied < len) { | |
278 | /* Try and load any missing data from the server. The | |
279 | * unmarshalling routine will take care of clearing any | |
280 | * bits that are beyond the EOF. | |
281 | */ | |
282 | ret = afs_fill_page(vnode, key, pos + copied, | |
283 | len - copied, page); | |
284 | if (ret < 0) | |
285 | return ret; | |
286 | } | |
287 | SetPageUptodate(page); | |
288 | } | |
289 | ||
31143d5d | 290 | set_page_dirty(page); |
31143d5d DH |
291 | if (PageDirty(page)) |
292 | _debug("dirtied"); | |
15b4650e | 293 | unlock_page(page); |
09cbfeaf | 294 | put_page(page); |
31143d5d | 295 | |
15b4650e | 296 | return copied; |
31143d5d DH |
297 | } |
298 | ||
299 | /* | |
300 | * kill all the pages in the given range | |
301 | */ | |
302 | static void afs_kill_pages(struct afs_vnode *vnode, bool error, | |
303 | pgoff_t first, pgoff_t last) | |
304 | { | |
305 | struct pagevec pv; | |
306 | unsigned count, loop; | |
307 | ||
308 | _enter("{%x:%u},%lx-%lx", | |
309 | vnode->fid.vid, vnode->fid.vnode, first, last); | |
310 | ||
311 | pagevec_init(&pv, 0); | |
312 | ||
313 | do { | |
314 | _debug("kill %lx-%lx", first, last); | |
315 | ||
316 | count = last - first + 1; | |
317 | if (count > PAGEVEC_SIZE) | |
318 | count = PAGEVEC_SIZE; | |
319 | pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping, | |
320 | first, count, pv.pages); | |
321 | ASSERTCMP(pv.nr, ==, count); | |
322 | ||
323 | for (loop = 0; loop < count; loop++) { | |
7286a35e DH |
324 | struct page *page = pv.pages[loop]; |
325 | ClearPageUptodate(page); | |
31143d5d | 326 | if (error) |
7286a35e DH |
327 | SetPageError(page); |
328 | if (PageWriteback(page)) | |
329 | end_page_writeback(page); | |
330 | if (page->index >= first) | |
331 | first = page->index + 1; | |
31143d5d DH |
332 | } |
333 | ||
334 | __pagevec_release(&pv); | |
335 | } while (first < last); | |
336 | ||
337 | _leave(""); | |
338 | } | |
339 | ||
340 | /* | |
341 | * synchronously write back the locked page and any subsequent non-locked dirty | |
342 | * pages also covered by the same writeback record | |
343 | */ | |
344 | static int afs_write_back_from_locked_page(struct afs_writeback *wb, | |
345 | struct page *primary_page) | |
346 | { | |
347 | struct page *pages[8], *page; | |
348 | unsigned long count; | |
349 | unsigned n, offset, to; | |
350 | pgoff_t start, first, last; | |
351 | int loop, ret; | |
352 | ||
353 | _enter(",%lx", primary_page->index); | |
354 | ||
355 | count = 1; | |
31143d5d DH |
356 | if (test_set_page_writeback(primary_page)) |
357 | BUG(); | |
358 | ||
359 | /* find all consecutive lockable dirty pages, stopping when we find a | |
360 | * page that is not immediately lockable, is not dirty or is missing, | |
361 | * or we reach the end of the range */ | |
362 | start = primary_page->index; | |
363 | if (start >= wb->last) | |
364 | goto no_more; | |
365 | start++; | |
366 | do { | |
367 | _debug("more %lx [%lx]", start, count); | |
368 | n = wb->last - start + 1; | |
369 | if (n > ARRAY_SIZE(pages)) | |
370 | n = ARRAY_SIZE(pages); | |
371 | n = find_get_pages_contig(wb->vnode->vfs_inode.i_mapping, | |
372 | start, n, pages); | |
373 | _debug("fgpc %u", n); | |
374 | if (n == 0) | |
375 | goto no_more; | |
376 | if (pages[0]->index != start) { | |
9d577b6a DH |
377 | do { |
378 | put_page(pages[--n]); | |
379 | } while (n > 0); | |
31143d5d DH |
380 | goto no_more; |
381 | } | |
382 | ||
383 | for (loop = 0; loop < n; loop++) { | |
384 | page = pages[loop]; | |
385 | if (page->index > wb->last) | |
386 | break; | |
529ae9aa | 387 | if (!trylock_page(page)) |
31143d5d DH |
388 | break; |
389 | if (!PageDirty(page) || | |
390 | page_private(page) != (unsigned long) wb) { | |
391 | unlock_page(page); | |
392 | break; | |
393 | } | |
394 | if (!clear_page_dirty_for_io(page)) | |
395 | BUG(); | |
396 | if (test_set_page_writeback(page)) | |
397 | BUG(); | |
398 | unlock_page(page); | |
399 | put_page(page); | |
400 | } | |
401 | count += loop; | |
402 | if (loop < n) { | |
403 | for (; loop < n; loop++) | |
404 | put_page(pages[loop]); | |
405 | goto no_more; | |
406 | } | |
407 | ||
408 | start += loop; | |
409 | } while (start <= wb->last && count < 65536); | |
410 | ||
411 | no_more: | |
412 | /* we now have a contiguous set of dirty pages, each with writeback set | |
413 | * and the dirty mark cleared; the first page is locked and must remain | |
414 | * so, all the rest are unlocked */ | |
415 | first = primary_page->index; | |
416 | last = first + count - 1; | |
417 | ||
418 | offset = (first == wb->first) ? wb->offset_first : 0; | |
419 | to = (last == wb->last) ? wb->to_last : PAGE_SIZE; | |
420 | ||
421 | _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to); | |
422 | ||
423 | ret = afs_vnode_store_data(wb, first, last, offset, to); | |
424 | if (ret < 0) { | |
425 | switch (ret) { | |
426 | case -EDQUOT: | |
427 | case -ENOSPC: | |
5114a97a | 428 | mapping_set_error(wb->vnode->vfs_inode.i_mapping, -ENOSPC); |
31143d5d DH |
429 | break; |
430 | case -EROFS: | |
431 | case -EIO: | |
432 | case -EREMOTEIO: | |
433 | case -EFBIG: | |
434 | case -ENOENT: | |
435 | case -ENOMEDIUM: | |
436 | case -ENXIO: | |
437 | afs_kill_pages(wb->vnode, true, first, last); | |
5114a97a | 438 | mapping_set_error(wb->vnode->vfs_inode.i_mapping, -EIO); |
31143d5d DH |
439 | break; |
440 | case -EACCES: | |
441 | case -EPERM: | |
442 | case -ENOKEY: | |
443 | case -EKEYEXPIRED: | |
444 | case -EKEYREJECTED: | |
445 | case -EKEYREVOKED: | |
446 | afs_kill_pages(wb->vnode, false, first, last); | |
447 | break; | |
448 | default: | |
449 | break; | |
450 | } | |
451 | } else { | |
452 | ret = count; | |
453 | } | |
454 | ||
455 | _leave(" = %d", ret); | |
456 | return ret; | |
457 | } | |
458 | ||
459 | /* | |
460 | * write a page back to the server | |
461 | * - the caller locked the page for us | |
462 | */ | |
463 | int afs_writepage(struct page *page, struct writeback_control *wbc) | |
464 | { | |
31143d5d DH |
465 | struct afs_writeback *wb; |
466 | int ret; | |
467 | ||
468 | _enter("{%lx},", page->index); | |
469 | ||
31143d5d DH |
470 | wb = (struct afs_writeback *) page_private(page); |
471 | ASSERT(wb != NULL); | |
472 | ||
473 | ret = afs_write_back_from_locked_page(wb, page); | |
474 | unlock_page(page); | |
475 | if (ret < 0) { | |
476 | _leave(" = %d", ret); | |
477 | return 0; | |
478 | } | |
479 | ||
480 | wbc->nr_to_write -= ret; | |
31143d5d DH |
481 | |
482 | _leave(" = 0"); | |
483 | return 0; | |
484 | } | |
485 | ||
486 | /* | |
487 | * write a region of pages back to the server | |
488 | */ | |
c1206a2c AB |
489 | static int afs_writepages_region(struct address_space *mapping, |
490 | struct writeback_control *wbc, | |
491 | pgoff_t index, pgoff_t end, pgoff_t *_next) | |
31143d5d | 492 | { |
31143d5d DH |
493 | struct afs_writeback *wb; |
494 | struct page *page; | |
495 | int ret, n; | |
496 | ||
497 | _enter(",,%lx,%lx,", index, end); | |
498 | ||
499 | do { | |
500 | n = find_get_pages_tag(mapping, &index, PAGECACHE_TAG_DIRTY, | |
501 | 1, &page); | |
502 | if (!n) | |
503 | break; | |
504 | ||
505 | _debug("wback %lx", page->index); | |
506 | ||
507 | if (page->index > end) { | |
508 | *_next = index; | |
09cbfeaf | 509 | put_page(page); |
31143d5d DH |
510 | _leave(" = 0 [%lx]", *_next); |
511 | return 0; | |
512 | } | |
513 | ||
514 | /* at this point we hold neither mapping->tree_lock nor lock on | |
515 | * the page itself: the page may be truncated or invalidated | |
516 | * (changing page->mapping to NULL), or even swizzled back from | |
517 | * swapper_space to tmpfs file mapping | |
518 | */ | |
519 | lock_page(page); | |
520 | ||
c5051c7b | 521 | if (page->mapping != mapping || !PageDirty(page)) { |
31143d5d | 522 | unlock_page(page); |
09cbfeaf | 523 | put_page(page); |
31143d5d DH |
524 | continue; |
525 | } | |
526 | ||
c5051c7b | 527 | if (PageWriteback(page)) { |
31143d5d | 528 | unlock_page(page); |
c5051c7b DH |
529 | if (wbc->sync_mode != WB_SYNC_NONE) |
530 | wait_on_page_writeback(page); | |
29c8bbbd | 531 | put_page(page); |
31143d5d DH |
532 | continue; |
533 | } | |
534 | ||
535 | wb = (struct afs_writeback *) page_private(page); | |
536 | ASSERT(wb != NULL); | |
537 | ||
538 | spin_lock(&wb->vnode->writeback_lock); | |
539 | wb->state = AFS_WBACK_WRITING; | |
540 | spin_unlock(&wb->vnode->writeback_lock); | |
541 | ||
65a15109 DH |
542 | if (!clear_page_dirty_for_io(page)) |
543 | BUG(); | |
31143d5d DH |
544 | ret = afs_write_back_from_locked_page(wb, page); |
545 | unlock_page(page); | |
09cbfeaf | 546 | put_page(page); |
31143d5d DH |
547 | if (ret < 0) { |
548 | _leave(" = %d", ret); | |
549 | return ret; | |
550 | } | |
551 | ||
552 | wbc->nr_to_write -= ret; | |
553 | ||
31143d5d DH |
554 | cond_resched(); |
555 | } while (index < end && wbc->nr_to_write > 0); | |
556 | ||
557 | *_next = index; | |
558 | _leave(" = 0 [%lx]", *_next); | |
559 | return 0; | |
560 | } | |
561 | ||
562 | /* | |
563 | * write some of the pending data back to the server | |
564 | */ | |
565 | int afs_writepages(struct address_space *mapping, | |
566 | struct writeback_control *wbc) | |
567 | { | |
31143d5d DH |
568 | pgoff_t start, end, next; |
569 | int ret; | |
570 | ||
571 | _enter(""); | |
572 | ||
31143d5d DH |
573 | if (wbc->range_cyclic) { |
574 | start = mapping->writeback_index; | |
575 | end = -1; | |
576 | ret = afs_writepages_region(mapping, wbc, start, end, &next); | |
1b430bee | 577 | if (start > 0 && wbc->nr_to_write > 0 && ret == 0) |
31143d5d DH |
578 | ret = afs_writepages_region(mapping, wbc, 0, start, |
579 | &next); | |
580 | mapping->writeback_index = next; | |
581 | } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { | |
09cbfeaf | 582 | end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT); |
31143d5d DH |
583 | ret = afs_writepages_region(mapping, wbc, 0, end, &next); |
584 | if (wbc->nr_to_write > 0) | |
585 | mapping->writeback_index = next; | |
586 | } else { | |
09cbfeaf KS |
587 | start = wbc->range_start >> PAGE_SHIFT; |
588 | end = wbc->range_end >> PAGE_SHIFT; | |
31143d5d DH |
589 | ret = afs_writepages_region(mapping, wbc, start, end, &next); |
590 | } | |
591 | ||
592 | _leave(" = %d", ret); | |
593 | return ret; | |
594 | } | |
595 | ||
31143d5d DH |
596 | /* |
597 | * completion of write to server | |
598 | */ | |
599 | void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call) | |
600 | { | |
601 | struct afs_writeback *wb = call->wb; | |
602 | struct pagevec pv; | |
603 | unsigned count, loop; | |
604 | pgoff_t first = call->first, last = call->last; | |
605 | bool free_wb; | |
606 | ||
607 | _enter("{%x:%u},{%lx-%lx}", | |
608 | vnode->fid.vid, vnode->fid.vnode, first, last); | |
609 | ||
610 | ASSERT(wb != NULL); | |
611 | ||
612 | pagevec_init(&pv, 0); | |
613 | ||
614 | do { | |
5bbf5d39 | 615 | _debug("done %lx-%lx", first, last); |
31143d5d DH |
616 | |
617 | count = last - first + 1; | |
618 | if (count > PAGEVEC_SIZE) | |
619 | count = PAGEVEC_SIZE; | |
620 | pv.nr = find_get_pages_contig(call->mapping, first, count, | |
621 | pv.pages); | |
622 | ASSERTCMP(pv.nr, ==, count); | |
623 | ||
624 | spin_lock(&vnode->writeback_lock); | |
625 | for (loop = 0; loop < count; loop++) { | |
626 | struct page *page = pv.pages[loop]; | |
627 | end_page_writeback(page); | |
628 | if (page_private(page) == (unsigned long) wb) { | |
629 | set_page_private(page, 0); | |
630 | ClearPagePrivate(page); | |
631 | wb->usage--; | |
632 | } | |
633 | } | |
634 | free_wb = false; | |
635 | if (wb->usage == 0) { | |
636 | afs_unlink_writeback(wb); | |
637 | free_wb = true; | |
638 | } | |
639 | spin_unlock(&vnode->writeback_lock); | |
640 | first += count; | |
641 | if (free_wb) { | |
642 | afs_free_writeback(wb); | |
643 | wb = NULL; | |
644 | } | |
645 | ||
646 | __pagevec_release(&pv); | |
5bbf5d39 | 647 | } while (first <= last); |
31143d5d DH |
648 | |
649 | _leave(""); | |
650 | } | |
651 | ||
652 | /* | |
653 | * write to an AFS file | |
654 | */ | |
50b5551d | 655 | ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) |
31143d5d | 656 | { |
496ad9aa | 657 | struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); |
31143d5d | 658 | ssize_t result; |
50b5551d | 659 | size_t count = iov_iter_count(from); |
31143d5d | 660 | |
50b5551d AV |
661 | _enter("{%x.%u},{%zu},", |
662 | vnode->fid.vid, vnode->fid.vnode, count); | |
31143d5d DH |
663 | |
664 | if (IS_SWAPFILE(&vnode->vfs_inode)) { | |
665 | printk(KERN_INFO | |
666 | "AFS: Attempt to write to active swap file!\n"); | |
667 | return -EBUSY; | |
668 | } | |
669 | ||
670 | if (!count) | |
671 | return 0; | |
672 | ||
50b5551d | 673 | result = generic_file_write_iter(iocb, from); |
31143d5d | 674 | |
31143d5d DH |
675 | _leave(" = %zd", result); |
676 | return result; | |
677 | } | |
678 | ||
679 | /* | |
680 | * flush the vnode to the fileserver | |
681 | */ | |
682 | int afs_writeback_all(struct afs_vnode *vnode) | |
683 | { | |
684 | struct address_space *mapping = vnode->vfs_inode.i_mapping; | |
685 | struct writeback_control wbc = { | |
31143d5d DH |
686 | .sync_mode = WB_SYNC_ALL, |
687 | .nr_to_write = LONG_MAX, | |
31143d5d DH |
688 | .range_cyclic = 1, |
689 | }; | |
690 | int ret; | |
691 | ||
692 | _enter(""); | |
693 | ||
694 | ret = mapping->a_ops->writepages(mapping, &wbc); | |
695 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); | |
696 | ||
697 | _leave(" = %d", ret); | |
698 | return ret; | |
699 | } | |
700 | ||
701 | /* | |
702 | * flush any dirty pages for this process, and check for write errors. | |
703 | * - the return status from this call provides a reliable indication of | |
704 | * whether any write errors occurred for this process. | |
705 | */ | |
02c24a82 | 706 | int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
31143d5d | 707 | { |
3c981bfc | 708 | struct inode *inode = file_inode(file); |
31143d5d | 709 | struct afs_writeback *wb, *xwb; |
3c981bfc | 710 | struct afs_vnode *vnode = AFS_FS_I(inode); |
31143d5d DH |
711 | int ret; |
712 | ||
3c981bfc AV |
713 | _enter("{%x:%u},{n=%pD},%d", |
714 | vnode->fid.vid, vnode->fid.vnode, file, | |
31143d5d DH |
715 | datasync); |
716 | ||
3b49c9a1 | 717 | ret = file_write_and_wait_range(file, start, end); |
02c24a82 JB |
718 | if (ret) |
719 | return ret; | |
5955102c | 720 | inode_lock(inode); |
02c24a82 | 721 | |
31143d5d DH |
722 | /* use a writeback record as a marker in the queue - when this reaches |
723 | * the front of the queue, all the outstanding writes are either | |
724 | * completed or rejected */ | |
725 | wb = kzalloc(sizeof(*wb), GFP_KERNEL); | |
02c24a82 JB |
726 | if (!wb) { |
727 | ret = -ENOMEM; | |
728 | goto out; | |
729 | } | |
31143d5d DH |
730 | wb->vnode = vnode; |
731 | wb->first = 0; | |
732 | wb->last = -1; | |
733 | wb->offset_first = 0; | |
734 | wb->to_last = PAGE_SIZE; | |
735 | wb->usage = 1; | |
736 | wb->state = AFS_WBACK_SYNCING; | |
737 | init_waitqueue_head(&wb->waitq); | |
738 | ||
739 | spin_lock(&vnode->writeback_lock); | |
740 | list_for_each_entry(xwb, &vnode->writebacks, link) { | |
741 | if (xwb->state == AFS_WBACK_PENDING) | |
742 | xwb->state = AFS_WBACK_CONFLICTING; | |
743 | } | |
744 | list_add_tail(&wb->link, &vnode->writebacks); | |
745 | spin_unlock(&vnode->writeback_lock); | |
746 | ||
747 | /* push all the outstanding writebacks to the server */ | |
748 | ret = afs_writeback_all(vnode); | |
749 | if (ret < 0) { | |
750 | afs_put_writeback(wb); | |
751 | _leave(" = %d [wb]", ret); | |
02c24a82 | 752 | goto out; |
31143d5d DH |
753 | } |
754 | ||
755 | /* wait for the preceding writes to actually complete */ | |
756 | ret = wait_event_interruptible(wb->waitq, | |
757 | wb->state == AFS_WBACK_COMPLETE || | |
758 | vnode->writebacks.next == &wb->link); | |
759 | afs_put_writeback(wb); | |
760 | _leave(" = %d", ret); | |
02c24a82 | 761 | out: |
5955102c | 762 | inode_unlock(inode); |
31143d5d DH |
763 | return ret; |
764 | } | |
9b3f26c9 | 765 | |
58fed94d DH |
766 | /* |
767 | * Flush out all outstanding writes on a file opened for writing when it is | |
768 | * closed. | |
769 | */ | |
770 | int afs_flush(struct file *file, fl_owner_t id) | |
771 | { | |
772 | _enter(""); | |
773 | ||
774 | if ((file->f_mode & FMODE_WRITE) == 0) | |
775 | return 0; | |
776 | ||
777 | return vfs_fsync(file, 0); | |
778 | } | |
779 | ||
9b3f26c9 DH |
780 | /* |
781 | * notification that a previously read-only page is about to become writable | |
782 | * - if it returns an error, the caller will deliver a bus error signal | |
783 | */ | |
784 | int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page) | |
785 | { | |
786 | struct afs_vnode *vnode = AFS_FS_I(vma->vm_file->f_mapping->host); | |
787 | ||
788 | _enter("{{%x:%u}},{%lx}", | |
789 | vnode->fid.vid, vnode->fid.vnode, page->index); | |
790 | ||
791 | /* wait for the page to be written to the cache before we allow it to | |
792 | * be modified */ | |
793 | #ifdef CONFIG_AFS_FSCACHE | |
794 | fscache_wait_on_page_write(vnode->cache, page); | |
795 | #endif | |
796 | ||
797 | _leave(" = 0"); | |
798 | return 0; | |
799 | } |