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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 | |
d2ddc776 | 106 | ret = afs_fetch_data(vnode, key, req); |
196ee9cd | 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; |
215804a9 | 131 | struct key *key = afs_file_key(file); |
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)); |
215804a9 | 258 | struct key *key = afs_file_key(file); |
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 | ||
d2ddc776 DH |
340 | /* |
341 | * write to a file | |
342 | */ | |
343 | static int afs_store_data(struct afs_writeback *wb, pgoff_t first, pgoff_t last, | |
344 | unsigned offset, unsigned to) | |
345 | { | |
346 | struct afs_fs_cursor fc; | |
347 | struct afs_vnode *vnode = wb->vnode; | |
348 | int ret; | |
349 | ||
350 | _enter("%s{%x:%u.%u},%x,%lx,%lx,%x,%x", | |
351 | vnode->volume->name, | |
352 | vnode->fid.vid, | |
353 | vnode->fid.vnode, | |
354 | vnode->fid.unique, | |
355 | key_serial(wb->key), | |
356 | first, last, offset, to); | |
357 | ||
358 | ret = -ERESTARTSYS; | |
359 | if (afs_begin_vnode_operation(&fc, vnode, wb->key)) { | |
360 | while (afs_select_fileserver(&fc)) { | |
361 | fc.cb_break = vnode->cb_break + vnode->cb_s_break; | |
362 | afs_fs_store_data(&fc, wb, first, last, offset, to); | |
363 | } | |
364 | ||
365 | afs_check_for_remote_deletion(&fc, fc.vnode); | |
366 | afs_vnode_commit_status(&fc, vnode, fc.cb_break); | |
367 | ret = afs_end_vnode_operation(&fc); | |
368 | } | |
369 | ||
370 | _leave(" = %d", ret); | |
371 | return ret; | |
372 | } | |
373 | ||
31143d5d DH |
374 | /* |
375 | * synchronously write back the locked page and any subsequent non-locked dirty | |
376 | * pages also covered by the same writeback record | |
377 | */ | |
378 | static int afs_write_back_from_locked_page(struct afs_writeback *wb, | |
379 | struct page *primary_page) | |
380 | { | |
381 | struct page *pages[8], *page; | |
382 | unsigned long count; | |
383 | unsigned n, offset, to; | |
384 | pgoff_t start, first, last; | |
385 | int loop, ret; | |
386 | ||
387 | _enter(",%lx", primary_page->index); | |
388 | ||
389 | count = 1; | |
31143d5d DH |
390 | if (test_set_page_writeback(primary_page)) |
391 | BUG(); | |
392 | ||
393 | /* find all consecutive lockable dirty pages, stopping when we find a | |
394 | * page that is not immediately lockable, is not dirty or is missing, | |
395 | * or we reach the end of the range */ | |
396 | start = primary_page->index; | |
397 | if (start >= wb->last) | |
398 | goto no_more; | |
399 | start++; | |
400 | do { | |
401 | _debug("more %lx [%lx]", start, count); | |
402 | n = wb->last - start + 1; | |
403 | if (n > ARRAY_SIZE(pages)) | |
404 | n = ARRAY_SIZE(pages); | |
405 | n = find_get_pages_contig(wb->vnode->vfs_inode.i_mapping, | |
406 | start, n, pages); | |
407 | _debug("fgpc %u", n); | |
408 | if (n == 0) | |
409 | goto no_more; | |
410 | if (pages[0]->index != start) { | |
9d577b6a DH |
411 | do { |
412 | put_page(pages[--n]); | |
413 | } while (n > 0); | |
31143d5d DH |
414 | goto no_more; |
415 | } | |
416 | ||
417 | for (loop = 0; loop < n; loop++) { | |
418 | page = pages[loop]; | |
419 | if (page->index > wb->last) | |
420 | break; | |
529ae9aa | 421 | if (!trylock_page(page)) |
31143d5d DH |
422 | break; |
423 | if (!PageDirty(page) || | |
424 | page_private(page) != (unsigned long) wb) { | |
425 | unlock_page(page); | |
426 | break; | |
427 | } | |
428 | if (!clear_page_dirty_for_io(page)) | |
429 | BUG(); | |
430 | if (test_set_page_writeback(page)) | |
431 | BUG(); | |
432 | unlock_page(page); | |
433 | put_page(page); | |
434 | } | |
435 | count += loop; | |
436 | if (loop < n) { | |
437 | for (; loop < n; loop++) | |
438 | put_page(pages[loop]); | |
439 | goto no_more; | |
440 | } | |
441 | ||
442 | start += loop; | |
443 | } while (start <= wb->last && count < 65536); | |
444 | ||
445 | no_more: | |
446 | /* we now have a contiguous set of dirty pages, each with writeback set | |
447 | * and the dirty mark cleared; the first page is locked and must remain | |
448 | * so, all the rest are unlocked */ | |
449 | first = primary_page->index; | |
450 | last = first + count - 1; | |
451 | ||
452 | offset = (first == wb->first) ? wb->offset_first : 0; | |
453 | to = (last == wb->last) ? wb->to_last : PAGE_SIZE; | |
454 | ||
455 | _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to); | |
456 | ||
d2ddc776 | 457 | ret = afs_store_data(wb, first, last, offset, to); |
31143d5d DH |
458 | if (ret < 0) { |
459 | switch (ret) { | |
460 | case -EDQUOT: | |
461 | case -ENOSPC: | |
5114a97a | 462 | mapping_set_error(wb->vnode->vfs_inode.i_mapping, -ENOSPC); |
31143d5d DH |
463 | break; |
464 | case -EROFS: | |
465 | case -EIO: | |
466 | case -EREMOTEIO: | |
467 | case -EFBIG: | |
468 | case -ENOENT: | |
469 | case -ENOMEDIUM: | |
470 | case -ENXIO: | |
471 | afs_kill_pages(wb->vnode, true, first, last); | |
5114a97a | 472 | mapping_set_error(wb->vnode->vfs_inode.i_mapping, -EIO); |
31143d5d DH |
473 | break; |
474 | case -EACCES: | |
475 | case -EPERM: | |
476 | case -ENOKEY: | |
477 | case -EKEYEXPIRED: | |
478 | case -EKEYREJECTED: | |
479 | case -EKEYREVOKED: | |
480 | afs_kill_pages(wb->vnode, false, first, last); | |
481 | break; | |
482 | default: | |
483 | break; | |
484 | } | |
485 | } else { | |
486 | ret = count; | |
487 | } | |
488 | ||
489 | _leave(" = %d", ret); | |
490 | return ret; | |
491 | } | |
492 | ||
493 | /* | |
494 | * write a page back to the server | |
495 | * - the caller locked the page for us | |
496 | */ | |
497 | int afs_writepage(struct page *page, struct writeback_control *wbc) | |
498 | { | |
31143d5d DH |
499 | struct afs_writeback *wb; |
500 | int ret; | |
501 | ||
502 | _enter("{%lx},", page->index); | |
503 | ||
31143d5d DH |
504 | wb = (struct afs_writeback *) page_private(page); |
505 | ASSERT(wb != NULL); | |
506 | ||
507 | ret = afs_write_back_from_locked_page(wb, page); | |
508 | unlock_page(page); | |
509 | if (ret < 0) { | |
510 | _leave(" = %d", ret); | |
511 | return 0; | |
512 | } | |
513 | ||
514 | wbc->nr_to_write -= ret; | |
31143d5d DH |
515 | |
516 | _leave(" = 0"); | |
517 | return 0; | |
518 | } | |
519 | ||
520 | /* | |
521 | * write a region of pages back to the server | |
522 | */ | |
c1206a2c AB |
523 | static int afs_writepages_region(struct address_space *mapping, |
524 | struct writeback_control *wbc, | |
525 | pgoff_t index, pgoff_t end, pgoff_t *_next) | |
31143d5d | 526 | { |
31143d5d DH |
527 | struct afs_writeback *wb; |
528 | struct page *page; | |
529 | int ret, n; | |
530 | ||
531 | _enter(",,%lx,%lx,", index, end); | |
532 | ||
533 | do { | |
534 | n = find_get_pages_tag(mapping, &index, PAGECACHE_TAG_DIRTY, | |
535 | 1, &page); | |
536 | if (!n) | |
537 | break; | |
538 | ||
539 | _debug("wback %lx", page->index); | |
540 | ||
541 | if (page->index > end) { | |
542 | *_next = index; | |
09cbfeaf | 543 | put_page(page); |
31143d5d DH |
544 | _leave(" = 0 [%lx]", *_next); |
545 | return 0; | |
546 | } | |
547 | ||
548 | /* at this point we hold neither mapping->tree_lock nor lock on | |
549 | * the page itself: the page may be truncated or invalidated | |
550 | * (changing page->mapping to NULL), or even swizzled back from | |
551 | * swapper_space to tmpfs file mapping | |
552 | */ | |
553 | lock_page(page); | |
554 | ||
c5051c7b | 555 | if (page->mapping != mapping || !PageDirty(page)) { |
31143d5d | 556 | unlock_page(page); |
09cbfeaf | 557 | put_page(page); |
31143d5d DH |
558 | continue; |
559 | } | |
560 | ||
c5051c7b | 561 | if (PageWriteback(page)) { |
31143d5d | 562 | unlock_page(page); |
c5051c7b DH |
563 | if (wbc->sync_mode != WB_SYNC_NONE) |
564 | wait_on_page_writeback(page); | |
29c8bbbd | 565 | put_page(page); |
31143d5d DH |
566 | continue; |
567 | } | |
568 | ||
569 | wb = (struct afs_writeback *) page_private(page); | |
570 | ASSERT(wb != NULL); | |
571 | ||
572 | spin_lock(&wb->vnode->writeback_lock); | |
573 | wb->state = AFS_WBACK_WRITING; | |
574 | spin_unlock(&wb->vnode->writeback_lock); | |
575 | ||
65a15109 DH |
576 | if (!clear_page_dirty_for_io(page)) |
577 | BUG(); | |
31143d5d DH |
578 | ret = afs_write_back_from_locked_page(wb, page); |
579 | unlock_page(page); | |
09cbfeaf | 580 | put_page(page); |
31143d5d DH |
581 | if (ret < 0) { |
582 | _leave(" = %d", ret); | |
583 | return ret; | |
584 | } | |
585 | ||
586 | wbc->nr_to_write -= ret; | |
587 | ||
31143d5d DH |
588 | cond_resched(); |
589 | } while (index < end && wbc->nr_to_write > 0); | |
590 | ||
591 | *_next = index; | |
592 | _leave(" = 0 [%lx]", *_next); | |
593 | return 0; | |
594 | } | |
595 | ||
596 | /* | |
597 | * write some of the pending data back to the server | |
598 | */ | |
599 | int afs_writepages(struct address_space *mapping, | |
600 | struct writeback_control *wbc) | |
601 | { | |
31143d5d DH |
602 | pgoff_t start, end, next; |
603 | int ret; | |
604 | ||
605 | _enter(""); | |
606 | ||
31143d5d DH |
607 | if (wbc->range_cyclic) { |
608 | start = mapping->writeback_index; | |
609 | end = -1; | |
610 | ret = afs_writepages_region(mapping, wbc, start, end, &next); | |
1b430bee | 611 | if (start > 0 && wbc->nr_to_write > 0 && ret == 0) |
31143d5d DH |
612 | ret = afs_writepages_region(mapping, wbc, 0, start, |
613 | &next); | |
614 | mapping->writeback_index = next; | |
615 | } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { | |
09cbfeaf | 616 | end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT); |
31143d5d DH |
617 | ret = afs_writepages_region(mapping, wbc, 0, end, &next); |
618 | if (wbc->nr_to_write > 0) | |
619 | mapping->writeback_index = next; | |
620 | } else { | |
09cbfeaf KS |
621 | start = wbc->range_start >> PAGE_SHIFT; |
622 | end = wbc->range_end >> PAGE_SHIFT; | |
31143d5d DH |
623 | ret = afs_writepages_region(mapping, wbc, start, end, &next); |
624 | } | |
625 | ||
626 | _leave(" = %d", ret); | |
627 | return ret; | |
628 | } | |
629 | ||
31143d5d DH |
630 | /* |
631 | * completion of write to server | |
632 | */ | |
633 | void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call) | |
634 | { | |
635 | struct afs_writeback *wb = call->wb; | |
636 | struct pagevec pv; | |
637 | unsigned count, loop; | |
638 | pgoff_t first = call->first, last = call->last; | |
639 | bool free_wb; | |
640 | ||
641 | _enter("{%x:%u},{%lx-%lx}", | |
642 | vnode->fid.vid, vnode->fid.vnode, first, last); | |
643 | ||
644 | ASSERT(wb != NULL); | |
645 | ||
646 | pagevec_init(&pv, 0); | |
647 | ||
648 | do { | |
5bbf5d39 | 649 | _debug("done %lx-%lx", first, last); |
31143d5d DH |
650 | |
651 | count = last - first + 1; | |
652 | if (count > PAGEVEC_SIZE) | |
653 | count = PAGEVEC_SIZE; | |
654 | pv.nr = find_get_pages_contig(call->mapping, first, count, | |
655 | pv.pages); | |
656 | ASSERTCMP(pv.nr, ==, count); | |
657 | ||
658 | spin_lock(&vnode->writeback_lock); | |
659 | for (loop = 0; loop < count; loop++) { | |
660 | struct page *page = pv.pages[loop]; | |
661 | end_page_writeback(page); | |
662 | if (page_private(page) == (unsigned long) wb) { | |
663 | set_page_private(page, 0); | |
664 | ClearPagePrivate(page); | |
665 | wb->usage--; | |
666 | } | |
667 | } | |
668 | free_wb = false; | |
669 | if (wb->usage == 0) { | |
670 | afs_unlink_writeback(wb); | |
671 | free_wb = true; | |
672 | } | |
673 | spin_unlock(&vnode->writeback_lock); | |
674 | first += count; | |
675 | if (free_wb) { | |
676 | afs_free_writeback(wb); | |
677 | wb = NULL; | |
678 | } | |
679 | ||
680 | __pagevec_release(&pv); | |
5bbf5d39 | 681 | } while (first <= last); |
31143d5d DH |
682 | |
683 | _leave(""); | |
684 | } | |
685 | ||
686 | /* | |
687 | * write to an AFS file | |
688 | */ | |
50b5551d | 689 | ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) |
31143d5d | 690 | { |
496ad9aa | 691 | struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); |
31143d5d | 692 | ssize_t result; |
50b5551d | 693 | size_t count = iov_iter_count(from); |
31143d5d | 694 | |
50b5551d AV |
695 | _enter("{%x.%u},{%zu},", |
696 | vnode->fid.vid, vnode->fid.vnode, count); | |
31143d5d DH |
697 | |
698 | if (IS_SWAPFILE(&vnode->vfs_inode)) { | |
699 | printk(KERN_INFO | |
700 | "AFS: Attempt to write to active swap file!\n"); | |
701 | return -EBUSY; | |
702 | } | |
703 | ||
704 | if (!count) | |
705 | return 0; | |
706 | ||
50b5551d | 707 | result = generic_file_write_iter(iocb, from); |
31143d5d | 708 | |
31143d5d DH |
709 | _leave(" = %zd", result); |
710 | return result; | |
711 | } | |
712 | ||
713 | /* | |
714 | * flush the vnode to the fileserver | |
715 | */ | |
716 | int afs_writeback_all(struct afs_vnode *vnode) | |
717 | { | |
718 | struct address_space *mapping = vnode->vfs_inode.i_mapping; | |
719 | struct writeback_control wbc = { | |
31143d5d DH |
720 | .sync_mode = WB_SYNC_ALL, |
721 | .nr_to_write = LONG_MAX, | |
31143d5d DH |
722 | .range_cyclic = 1, |
723 | }; | |
724 | int ret; | |
725 | ||
726 | _enter(""); | |
727 | ||
728 | ret = mapping->a_ops->writepages(mapping, &wbc); | |
729 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); | |
730 | ||
731 | _leave(" = %d", ret); | |
732 | return ret; | |
733 | } | |
734 | ||
735 | /* | |
736 | * flush any dirty pages for this process, and check for write errors. | |
737 | * - the return status from this call provides a reliable indication of | |
738 | * whether any write errors occurred for this process. | |
739 | */ | |
02c24a82 | 740 | int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
31143d5d | 741 | { |
3c981bfc | 742 | struct inode *inode = file_inode(file); |
31143d5d | 743 | struct afs_writeback *wb, *xwb; |
3c981bfc | 744 | struct afs_vnode *vnode = AFS_FS_I(inode); |
31143d5d DH |
745 | int ret; |
746 | ||
3c981bfc AV |
747 | _enter("{%x:%u},{n=%pD},%d", |
748 | vnode->fid.vid, vnode->fid.vnode, file, | |
31143d5d DH |
749 | datasync); |
750 | ||
3b49c9a1 | 751 | ret = file_write_and_wait_range(file, start, end); |
02c24a82 JB |
752 | if (ret) |
753 | return ret; | |
5955102c | 754 | inode_lock(inode); |
02c24a82 | 755 | |
31143d5d DH |
756 | /* use a writeback record as a marker in the queue - when this reaches |
757 | * the front of the queue, all the outstanding writes are either | |
758 | * completed or rejected */ | |
759 | wb = kzalloc(sizeof(*wb), GFP_KERNEL); | |
02c24a82 JB |
760 | if (!wb) { |
761 | ret = -ENOMEM; | |
762 | goto out; | |
763 | } | |
31143d5d DH |
764 | wb->vnode = vnode; |
765 | wb->first = 0; | |
766 | wb->last = -1; | |
767 | wb->offset_first = 0; | |
768 | wb->to_last = PAGE_SIZE; | |
769 | wb->usage = 1; | |
770 | wb->state = AFS_WBACK_SYNCING; | |
771 | init_waitqueue_head(&wb->waitq); | |
772 | ||
773 | spin_lock(&vnode->writeback_lock); | |
774 | list_for_each_entry(xwb, &vnode->writebacks, link) { | |
775 | if (xwb->state == AFS_WBACK_PENDING) | |
776 | xwb->state = AFS_WBACK_CONFLICTING; | |
777 | } | |
778 | list_add_tail(&wb->link, &vnode->writebacks); | |
779 | spin_unlock(&vnode->writeback_lock); | |
780 | ||
781 | /* push all the outstanding writebacks to the server */ | |
782 | ret = afs_writeback_all(vnode); | |
783 | if (ret < 0) { | |
784 | afs_put_writeback(wb); | |
785 | _leave(" = %d [wb]", ret); | |
02c24a82 | 786 | goto out; |
31143d5d DH |
787 | } |
788 | ||
789 | /* wait for the preceding writes to actually complete */ | |
790 | ret = wait_event_interruptible(wb->waitq, | |
791 | wb->state == AFS_WBACK_COMPLETE || | |
792 | vnode->writebacks.next == &wb->link); | |
793 | afs_put_writeback(wb); | |
794 | _leave(" = %d", ret); | |
02c24a82 | 795 | out: |
5955102c | 796 | inode_unlock(inode); |
31143d5d DH |
797 | return ret; |
798 | } | |
9b3f26c9 | 799 | |
58fed94d DH |
800 | /* |
801 | * Flush out all outstanding writes on a file opened for writing when it is | |
802 | * closed. | |
803 | */ | |
804 | int afs_flush(struct file *file, fl_owner_t id) | |
805 | { | |
806 | _enter(""); | |
807 | ||
808 | if ((file->f_mode & FMODE_WRITE) == 0) | |
809 | return 0; | |
810 | ||
811 | return vfs_fsync(file, 0); | |
812 | } | |
813 | ||
9b3f26c9 DH |
814 | /* |
815 | * notification that a previously read-only page is about to become writable | |
816 | * - if it returns an error, the caller will deliver a bus error signal | |
817 | */ | |
818 | int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page) | |
819 | { | |
820 | struct afs_vnode *vnode = AFS_FS_I(vma->vm_file->f_mapping->host); | |
821 | ||
822 | _enter("{{%x:%u}},{%lx}", | |
823 | vnode->fid.vid, vnode->fid.vnode, page->index); | |
824 | ||
825 | /* wait for the page to be written to the cache before we allow it to | |
826 | * be modified */ | |
827 | #ifdef CONFIG_AFS_FSCACHE | |
828 | fscache_wait_on_page_write(vnode->cache, page); | |
829 | #endif | |
830 | ||
831 | _leave(" = 0"); | |
832 | return 0; | |
833 | } |