Loading...
1/* AFS filesystem file handling
2 *
3 * Copyright (C) 2002, 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 */
11
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/fs.h>
16#include <linux/pagemap.h>
17#include <linux/writeback.h>
18#include <linux/gfp.h>
19#include <linux/task_io_accounting_ops.h>
20#include "internal.h"
21
22static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
23static int afs_readpage(struct file *file, struct page *page);
24static void afs_invalidatepage(struct page *page, unsigned int offset,
25 unsigned int length);
26static int afs_releasepage(struct page *page, gfp_t gfp_flags);
27
28static int afs_readpages(struct file *filp, struct address_space *mapping,
29 struct list_head *pages, unsigned nr_pages);
30
31const struct file_operations afs_file_operations = {
32 .open = afs_open,
33 .release = afs_release,
34 .llseek = generic_file_llseek,
35 .read_iter = generic_file_read_iter,
36 .write_iter = afs_file_write,
37 .mmap = afs_file_mmap,
38 .splice_read = generic_file_splice_read,
39 .fsync = afs_fsync,
40 .lock = afs_lock,
41 .flock = afs_flock,
42};
43
44const struct inode_operations afs_file_inode_operations = {
45 .getattr = afs_getattr,
46 .setattr = afs_setattr,
47 .permission = afs_permission,
48 .listxattr = afs_listxattr,
49};
50
51const struct address_space_operations afs_fs_aops = {
52 .readpage = afs_readpage,
53 .readpages = afs_readpages,
54 .set_page_dirty = afs_set_page_dirty,
55 .launder_page = afs_launder_page,
56 .releasepage = afs_releasepage,
57 .invalidatepage = afs_invalidatepage,
58 .write_begin = afs_write_begin,
59 .write_end = afs_write_end,
60 .writepage = afs_writepage,
61 .writepages = afs_writepages,
62};
63
64static const struct vm_operations_struct afs_vm_ops = {
65 .fault = filemap_fault,
66 .map_pages = filemap_map_pages,
67 .page_mkwrite = afs_page_mkwrite,
68};
69
70/*
71 * Discard a pin on a writeback key.
72 */
73void afs_put_wb_key(struct afs_wb_key *wbk)
74{
75 if (refcount_dec_and_test(&wbk->usage)) {
76 key_put(wbk->key);
77 kfree(wbk);
78 }
79}
80
81/*
82 * Cache key for writeback.
83 */
84int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
85{
86 struct afs_wb_key *wbk, *p;
87
88 wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL);
89 if (!wbk)
90 return -ENOMEM;
91 refcount_set(&wbk->usage, 2);
92 wbk->key = af->key;
93
94 spin_lock(&vnode->wb_lock);
95 list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
96 if (p->key == wbk->key)
97 goto found;
98 }
99
100 key_get(wbk->key);
101 list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
102 spin_unlock(&vnode->wb_lock);
103 af->wb = wbk;
104 return 0;
105
106found:
107 refcount_inc(&p->usage);
108 spin_unlock(&vnode->wb_lock);
109 af->wb = p;
110 kfree(wbk);
111 return 0;
112}
113
114/*
115 * open an AFS file or directory and attach a key to it
116 */
117int afs_open(struct inode *inode, struct file *file)
118{
119 struct afs_vnode *vnode = AFS_FS_I(inode);
120 struct afs_file *af;
121 struct key *key;
122 int ret;
123
124 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
125
126 key = afs_request_key(vnode->volume->cell);
127 if (IS_ERR(key)) {
128 ret = PTR_ERR(key);
129 goto error;
130 }
131
132 af = kzalloc(sizeof(*af), GFP_KERNEL);
133 if (!af) {
134 ret = -ENOMEM;
135 goto error_key;
136 }
137 af->key = key;
138
139 ret = afs_validate(vnode, key);
140 if (ret < 0)
141 goto error_af;
142
143 if (file->f_mode & FMODE_WRITE) {
144 ret = afs_cache_wb_key(vnode, af);
145 if (ret < 0)
146 goto error_af;
147 }
148
149 if (file->f_flags & O_TRUNC)
150 set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
151
152 file->private_data = af;
153 _leave(" = 0");
154 return 0;
155
156error_af:
157 kfree(af);
158error_key:
159 key_put(key);
160error:
161 _leave(" = %d", ret);
162 return ret;
163}
164
165/*
166 * release an AFS file or directory and discard its key
167 */
168int afs_release(struct inode *inode, struct file *file)
169{
170 struct afs_vnode *vnode = AFS_FS_I(inode);
171 struct afs_file *af = file->private_data;
172
173 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
174
175 if ((file->f_mode & FMODE_WRITE))
176 return vfs_fsync(file, 0);
177
178 file->private_data = NULL;
179 if (af->wb)
180 afs_put_wb_key(af->wb);
181 key_put(af->key);
182 kfree(af);
183 afs_prune_wb_keys(vnode);
184 _leave(" = 0");
185 return 0;
186}
187
188/*
189 * Dispose of a ref to a read record.
190 */
191void afs_put_read(struct afs_read *req)
192{
193 int i;
194
195 if (refcount_dec_and_test(&req->usage)) {
196 for (i = 0; i < req->nr_pages; i++)
197 if (req->pages[i])
198 put_page(req->pages[i]);
199 if (req->pages != req->array)
200 kfree(req->pages);
201 kfree(req);
202 }
203}
204
205#ifdef CONFIG_AFS_FSCACHE
206/*
207 * deal with notification that a page was read from the cache
208 */
209static void afs_file_readpage_read_complete(struct page *page,
210 void *data,
211 int error)
212{
213 _enter("%p,%p,%d", page, data, error);
214
215 /* if the read completes with an error, we just unlock the page and let
216 * the VM reissue the readpage */
217 if (!error)
218 SetPageUptodate(page);
219 unlock_page(page);
220}
221#endif
222
223/*
224 * Fetch file data from the volume.
225 */
226int afs_fetch_data(struct afs_vnode *vnode, struct key *key, struct afs_read *desc)
227{
228 struct afs_fs_cursor fc;
229 int ret;
230
231 _enter("%s{%x:%u.%u},%x,,,",
232 vnode->volume->name,
233 vnode->fid.vid,
234 vnode->fid.vnode,
235 vnode->fid.unique,
236 key_serial(key));
237
238 ret = -ERESTARTSYS;
239 if (afs_begin_vnode_operation(&fc, vnode, key)) {
240 while (afs_select_fileserver(&fc)) {
241 fc.cb_break = afs_calc_vnode_cb_break(vnode);
242 afs_fs_fetch_data(&fc, desc);
243 }
244
245 afs_check_for_remote_deletion(&fc, fc.vnode);
246 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
247 ret = afs_end_vnode_operation(&fc);
248 }
249
250 if (ret == 0) {
251 afs_stat_v(vnode, n_fetches);
252 atomic_long_add(desc->actual_len,
253 &afs_v2net(vnode)->n_fetch_bytes);
254 }
255
256 _leave(" = %d", ret);
257 return ret;
258}
259
260/*
261 * read page from file, directory or symlink, given a key to use
262 */
263int afs_page_filler(void *data, struct page *page)
264{
265 struct inode *inode = page->mapping->host;
266 struct afs_vnode *vnode = AFS_FS_I(inode);
267 struct afs_read *req;
268 struct key *key = data;
269 int ret;
270
271 _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
272
273 BUG_ON(!PageLocked(page));
274
275 ret = -ESTALE;
276 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
277 goto error;
278
279 /* is it cached? */
280#ifdef CONFIG_AFS_FSCACHE
281 ret = fscache_read_or_alloc_page(vnode->cache,
282 page,
283 afs_file_readpage_read_complete,
284 NULL,
285 GFP_KERNEL);
286#else
287 ret = -ENOBUFS;
288#endif
289 switch (ret) {
290 /* read BIO submitted (page in cache) */
291 case 0:
292 break;
293
294 /* page not yet cached */
295 case -ENODATA:
296 _debug("cache said ENODATA");
297 goto go_on;
298
299 /* page will not be cached */
300 case -ENOBUFS:
301 _debug("cache said ENOBUFS");
302 default:
303 go_on:
304 req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *),
305 GFP_KERNEL);
306 if (!req)
307 goto enomem;
308
309 /* We request a full page. If the page is a partial one at the
310 * end of the file, the server will return a short read and the
311 * unmarshalling code will clear the unfilled space.
312 */
313 refcount_set(&req->usage, 1);
314 req->pos = (loff_t)page->index << PAGE_SHIFT;
315 req->len = PAGE_SIZE;
316 req->nr_pages = 1;
317 req->pages = req->array;
318 req->pages[0] = page;
319 get_page(page);
320
321 /* read the contents of the file from the server into the
322 * page */
323 ret = afs_fetch_data(vnode, key, req);
324 afs_put_read(req);
325
326 if (ret < 0) {
327 if (ret == -ENOENT) {
328 _debug("got NOENT from server"
329 " - marking file deleted and stale");
330 set_bit(AFS_VNODE_DELETED, &vnode->flags);
331 ret = -ESTALE;
332 }
333
334#ifdef CONFIG_AFS_FSCACHE
335 fscache_uncache_page(vnode->cache, page);
336#endif
337 BUG_ON(PageFsCache(page));
338
339 if (ret == -EINTR ||
340 ret == -ENOMEM ||
341 ret == -ERESTARTSYS ||
342 ret == -EAGAIN)
343 goto error;
344 goto io_error;
345 }
346
347 SetPageUptodate(page);
348
349 /* send the page to the cache */
350#ifdef CONFIG_AFS_FSCACHE
351 if (PageFsCache(page) &&
352 fscache_write_page(vnode->cache, page, vnode->status.size,
353 GFP_KERNEL) != 0) {
354 fscache_uncache_page(vnode->cache, page);
355 BUG_ON(PageFsCache(page));
356 }
357#endif
358 unlock_page(page);
359 }
360
361 _leave(" = 0");
362 return 0;
363
364io_error:
365 SetPageError(page);
366 goto error;
367enomem:
368 ret = -ENOMEM;
369error:
370 unlock_page(page);
371 _leave(" = %d", ret);
372 return ret;
373}
374
375/*
376 * read page from file, directory or symlink, given a file to nominate the key
377 * to be used
378 */
379static int afs_readpage(struct file *file, struct page *page)
380{
381 struct key *key;
382 int ret;
383
384 if (file) {
385 key = afs_file_key(file);
386 ASSERT(key != NULL);
387 ret = afs_page_filler(key, page);
388 } else {
389 struct inode *inode = page->mapping->host;
390 key = afs_request_key(AFS_FS_S(inode->i_sb)->cell);
391 if (IS_ERR(key)) {
392 ret = PTR_ERR(key);
393 } else {
394 ret = afs_page_filler(key, page);
395 key_put(key);
396 }
397 }
398 return ret;
399}
400
401/*
402 * Make pages available as they're filled.
403 */
404static void afs_readpages_page_done(struct afs_call *call, struct afs_read *req)
405{
406#ifdef CONFIG_AFS_FSCACHE
407 struct afs_vnode *vnode = call->reply[0];
408#endif
409 struct page *page = req->pages[req->index];
410
411 req->pages[req->index] = NULL;
412 SetPageUptodate(page);
413
414 /* send the page to the cache */
415#ifdef CONFIG_AFS_FSCACHE
416 if (PageFsCache(page) &&
417 fscache_write_page(vnode->cache, page, vnode->status.size,
418 GFP_KERNEL) != 0) {
419 fscache_uncache_page(vnode->cache, page);
420 BUG_ON(PageFsCache(page));
421 }
422#endif
423 unlock_page(page);
424 put_page(page);
425}
426
427/*
428 * Read a contiguous set of pages.
429 */
430static int afs_readpages_one(struct file *file, struct address_space *mapping,
431 struct list_head *pages)
432{
433 struct afs_vnode *vnode = AFS_FS_I(mapping->host);
434 struct afs_read *req;
435 struct list_head *p;
436 struct page *first, *page;
437 struct key *key = afs_file_key(file);
438 pgoff_t index;
439 int ret, n, i;
440
441 /* Count the number of contiguous pages at the front of the list. Note
442 * that the list goes prev-wards rather than next-wards.
443 */
444 first = list_entry(pages->prev, struct page, lru);
445 index = first->index + 1;
446 n = 1;
447 for (p = first->lru.prev; p != pages; p = p->prev) {
448 page = list_entry(p, struct page, lru);
449 if (page->index != index)
450 break;
451 index++;
452 n++;
453 }
454
455 req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *) * n,
456 GFP_NOFS);
457 if (!req)
458 return -ENOMEM;
459
460 refcount_set(&req->usage, 1);
461 req->page_done = afs_readpages_page_done;
462 req->pos = first->index;
463 req->pos <<= PAGE_SHIFT;
464 req->pages = req->array;
465
466 /* Transfer the pages to the request. We add them in until one fails
467 * to add to the LRU and then we stop (as that'll make a hole in the
468 * contiguous run.
469 *
470 * Note that it's possible for the file size to change whilst we're
471 * doing this, but we rely on the server returning less than we asked
472 * for if the file shrank. We also rely on this to deal with a partial
473 * page at the end of the file.
474 */
475 do {
476 page = list_entry(pages->prev, struct page, lru);
477 list_del(&page->lru);
478 index = page->index;
479 if (add_to_page_cache_lru(page, mapping, index,
480 readahead_gfp_mask(mapping))) {
481#ifdef CONFIG_AFS_FSCACHE
482 fscache_uncache_page(vnode->cache, page);
483#endif
484 put_page(page);
485 break;
486 }
487
488 req->pages[req->nr_pages++] = page;
489 req->len += PAGE_SIZE;
490 } while (req->nr_pages < n);
491
492 if (req->nr_pages == 0) {
493 kfree(req);
494 return 0;
495 }
496
497 ret = afs_fetch_data(vnode, key, req);
498 if (ret < 0)
499 goto error;
500
501 task_io_account_read(PAGE_SIZE * req->nr_pages);
502 afs_put_read(req);
503 return 0;
504
505error:
506 if (ret == -ENOENT) {
507 _debug("got NOENT from server"
508 " - marking file deleted and stale");
509 set_bit(AFS_VNODE_DELETED, &vnode->flags);
510 ret = -ESTALE;
511 }
512
513 for (i = 0; i < req->nr_pages; i++) {
514 page = req->pages[i];
515 if (page) {
516#ifdef CONFIG_AFS_FSCACHE
517 fscache_uncache_page(vnode->cache, page);
518#endif
519 SetPageError(page);
520 unlock_page(page);
521 }
522 }
523
524 afs_put_read(req);
525 return ret;
526}
527
528/*
529 * read a set of pages
530 */
531static int afs_readpages(struct file *file, struct address_space *mapping,
532 struct list_head *pages, unsigned nr_pages)
533{
534 struct key *key = afs_file_key(file);
535 struct afs_vnode *vnode;
536 int ret = 0;
537
538 _enter("{%d},{%lu},,%d",
539 key_serial(key), mapping->host->i_ino, nr_pages);
540
541 ASSERT(key != NULL);
542
543 vnode = AFS_FS_I(mapping->host);
544 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
545 _leave(" = -ESTALE");
546 return -ESTALE;
547 }
548
549 /* attempt to read as many of the pages as possible */
550#ifdef CONFIG_AFS_FSCACHE
551 ret = fscache_read_or_alloc_pages(vnode->cache,
552 mapping,
553 pages,
554 &nr_pages,
555 afs_file_readpage_read_complete,
556 NULL,
557 mapping_gfp_mask(mapping));
558#else
559 ret = -ENOBUFS;
560#endif
561
562 switch (ret) {
563 /* all pages are being read from the cache */
564 case 0:
565 BUG_ON(!list_empty(pages));
566 BUG_ON(nr_pages != 0);
567 _leave(" = 0 [reading all]");
568 return 0;
569
570 /* there were pages that couldn't be read from the cache */
571 case -ENODATA:
572 case -ENOBUFS:
573 break;
574
575 /* other error */
576 default:
577 _leave(" = %d", ret);
578 return ret;
579 }
580
581 while (!list_empty(pages)) {
582 ret = afs_readpages_one(file, mapping, pages);
583 if (ret < 0)
584 break;
585 }
586
587 _leave(" = %d [netting]", ret);
588 return ret;
589}
590
591/*
592 * invalidate part or all of a page
593 * - release a page and clean up its private data if offset is 0 (indicating
594 * the entire page)
595 */
596static void afs_invalidatepage(struct page *page, unsigned int offset,
597 unsigned int length)
598{
599 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
600 unsigned long priv;
601
602 _enter("{%lu},%u,%u", page->index, offset, length);
603
604 BUG_ON(!PageLocked(page));
605
606 /* we clean up only if the entire page is being invalidated */
607 if (offset == 0 && length == PAGE_SIZE) {
608#ifdef CONFIG_AFS_FSCACHE
609 if (PageFsCache(page)) {
610 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
611 fscache_wait_on_page_write(vnode->cache, page);
612 fscache_uncache_page(vnode->cache, page);
613 }
614#endif
615
616 if (PagePrivate(page)) {
617 priv = page_private(page);
618 trace_afs_page_dirty(vnode, tracepoint_string("inval"),
619 page->index, priv);
620 set_page_private(page, 0);
621 ClearPagePrivate(page);
622 }
623 }
624
625 _leave("");
626}
627
628/*
629 * release a page and clean up its private state if it's not busy
630 * - return true if the page can now be released, false if not
631 */
632static int afs_releasepage(struct page *page, gfp_t gfp_flags)
633{
634 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
635 unsigned long priv;
636
637 _enter("{{%x:%u}[%lu],%lx},%x",
638 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
639 gfp_flags);
640
641 /* deny if page is being written to the cache and the caller hasn't
642 * elected to wait */
643#ifdef CONFIG_AFS_FSCACHE
644 if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
645 _leave(" = F [cache busy]");
646 return 0;
647 }
648#endif
649
650 if (PagePrivate(page)) {
651 priv = page_private(page);
652 trace_afs_page_dirty(vnode, tracepoint_string("rel"),
653 page->index, priv);
654 set_page_private(page, 0);
655 ClearPagePrivate(page);
656 }
657
658 /* indicate that the page can be released */
659 _leave(" = T");
660 return 1;
661}
662
663/*
664 * Handle setting up a memory mapping on an AFS file.
665 */
666static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
667{
668 int ret;
669
670 ret = generic_file_mmap(file, vma);
671 if (ret == 0)
672 vma->vm_ops = &afs_vm_ops;
673 return ret;
674}
1/* AFS filesystem file handling
2 *
3 * Copyright (C) 2002, 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 */
11
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/fs.h>
16#include <linux/pagemap.h>
17#include <linux/writeback.h>
18#include <linux/gfp.h>
19#include "internal.h"
20
21static int afs_readpage(struct file *file, struct page *page);
22static void afs_invalidatepage(struct page *page, unsigned int offset,
23 unsigned int length);
24static int afs_releasepage(struct page *page, gfp_t gfp_flags);
25static int afs_launder_page(struct page *page);
26
27static int afs_readpages(struct file *filp, struct address_space *mapping,
28 struct list_head *pages, unsigned nr_pages);
29
30const struct file_operations afs_file_operations = {
31 .open = afs_open,
32 .release = afs_release,
33 .llseek = generic_file_llseek,
34 .read_iter = generic_file_read_iter,
35 .write_iter = afs_file_write,
36 .mmap = generic_file_readonly_mmap,
37 .splice_read = generic_file_splice_read,
38 .fsync = afs_fsync,
39 .lock = afs_lock,
40 .flock = afs_flock,
41};
42
43const struct inode_operations afs_file_inode_operations = {
44 .getattr = afs_getattr,
45 .setattr = afs_setattr,
46 .permission = afs_permission,
47};
48
49const struct address_space_operations afs_fs_aops = {
50 .readpage = afs_readpage,
51 .readpages = afs_readpages,
52 .set_page_dirty = afs_set_page_dirty,
53 .launder_page = afs_launder_page,
54 .releasepage = afs_releasepage,
55 .invalidatepage = afs_invalidatepage,
56 .write_begin = afs_write_begin,
57 .write_end = afs_write_end,
58 .writepage = afs_writepage,
59 .writepages = afs_writepages,
60};
61
62/*
63 * open an AFS file or directory and attach a key to it
64 */
65int afs_open(struct inode *inode, struct file *file)
66{
67 struct afs_vnode *vnode = AFS_FS_I(inode);
68 struct key *key;
69 int ret;
70
71 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
72
73 key = afs_request_key(vnode->volume->cell);
74 if (IS_ERR(key)) {
75 _leave(" = %ld [key]", PTR_ERR(key));
76 return PTR_ERR(key);
77 }
78
79 ret = afs_validate(vnode, key);
80 if (ret < 0) {
81 _leave(" = %d [val]", ret);
82 return ret;
83 }
84
85 file->private_data = key;
86 _leave(" = 0");
87 return 0;
88}
89
90/*
91 * release an AFS file or directory and discard its key
92 */
93int afs_release(struct inode *inode, struct file *file)
94{
95 struct afs_vnode *vnode = AFS_FS_I(inode);
96
97 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
98
99 key_put(file->private_data);
100 _leave(" = 0");
101 return 0;
102}
103
104#ifdef CONFIG_AFS_FSCACHE
105/*
106 * deal with notification that a page was read from the cache
107 */
108static void afs_file_readpage_read_complete(struct page *page,
109 void *data,
110 int error)
111{
112 _enter("%p,%p,%d", page, data, error);
113
114 /* if the read completes with an error, we just unlock the page and let
115 * the VM reissue the readpage */
116 if (!error)
117 SetPageUptodate(page);
118 unlock_page(page);
119}
120#endif
121
122/*
123 * read page from file, directory or symlink, given a key to use
124 */
125int afs_page_filler(void *data, struct page *page)
126{
127 struct inode *inode = page->mapping->host;
128 struct afs_vnode *vnode = AFS_FS_I(inode);
129 struct key *key = data;
130 size_t len;
131 off_t offset;
132 int ret;
133
134 _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
135
136 BUG_ON(!PageLocked(page));
137
138 ret = -ESTALE;
139 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
140 goto error;
141
142 /* is it cached? */
143#ifdef CONFIG_AFS_FSCACHE
144 ret = fscache_read_or_alloc_page(vnode->cache,
145 page,
146 afs_file_readpage_read_complete,
147 NULL,
148 GFP_KERNEL);
149#else
150 ret = -ENOBUFS;
151#endif
152 switch (ret) {
153 /* read BIO submitted (page in cache) */
154 case 0:
155 break;
156
157 /* page not yet cached */
158 case -ENODATA:
159 _debug("cache said ENODATA");
160 goto go_on;
161
162 /* page will not be cached */
163 case -ENOBUFS:
164 _debug("cache said ENOBUFS");
165 default:
166 go_on:
167 offset = page->index << PAGE_SHIFT;
168 len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);
169
170 /* read the contents of the file from the server into the
171 * page */
172 ret = afs_vnode_fetch_data(vnode, key, offset, len, page);
173 if (ret < 0) {
174 if (ret == -ENOENT) {
175 _debug("got NOENT from server"
176 " - marking file deleted and stale");
177 set_bit(AFS_VNODE_DELETED, &vnode->flags);
178 ret = -ESTALE;
179 }
180
181#ifdef CONFIG_AFS_FSCACHE
182 fscache_uncache_page(vnode->cache, page);
183#endif
184 BUG_ON(PageFsCache(page));
185 goto error;
186 }
187
188 SetPageUptodate(page);
189
190 /* send the page to the cache */
191#ifdef CONFIG_AFS_FSCACHE
192 if (PageFsCache(page) &&
193 fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) {
194 fscache_uncache_page(vnode->cache, page);
195 BUG_ON(PageFsCache(page));
196 }
197#endif
198 unlock_page(page);
199 }
200
201 _leave(" = 0");
202 return 0;
203
204error:
205 SetPageError(page);
206 unlock_page(page);
207 _leave(" = %d", ret);
208 return ret;
209}
210
211/*
212 * read page from file, directory or symlink, given a file to nominate the key
213 * to be used
214 */
215static int afs_readpage(struct file *file, struct page *page)
216{
217 struct key *key;
218 int ret;
219
220 if (file) {
221 key = file->private_data;
222 ASSERT(key != NULL);
223 ret = afs_page_filler(key, page);
224 } else {
225 struct inode *inode = page->mapping->host;
226 key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
227 if (IS_ERR(key)) {
228 ret = PTR_ERR(key);
229 } else {
230 ret = afs_page_filler(key, page);
231 key_put(key);
232 }
233 }
234 return ret;
235}
236
237/*
238 * read a set of pages
239 */
240static int afs_readpages(struct file *file, struct address_space *mapping,
241 struct list_head *pages, unsigned nr_pages)
242{
243 struct key *key = file->private_data;
244 struct afs_vnode *vnode;
245 int ret = 0;
246
247 _enter("{%d},{%lu},,%d",
248 key_serial(key), mapping->host->i_ino, nr_pages);
249
250 ASSERT(key != NULL);
251
252 vnode = AFS_FS_I(mapping->host);
253 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
254 _leave(" = -ESTALE");
255 return -ESTALE;
256 }
257
258 /* attempt to read as many of the pages as possible */
259#ifdef CONFIG_AFS_FSCACHE
260 ret = fscache_read_or_alloc_pages(vnode->cache,
261 mapping,
262 pages,
263 &nr_pages,
264 afs_file_readpage_read_complete,
265 NULL,
266 mapping_gfp_mask(mapping));
267#else
268 ret = -ENOBUFS;
269#endif
270
271 switch (ret) {
272 /* all pages are being read from the cache */
273 case 0:
274 BUG_ON(!list_empty(pages));
275 BUG_ON(nr_pages != 0);
276 _leave(" = 0 [reading all]");
277 return 0;
278
279 /* there were pages that couldn't be read from the cache */
280 case -ENODATA:
281 case -ENOBUFS:
282 break;
283
284 /* other error */
285 default:
286 _leave(" = %d", ret);
287 return ret;
288 }
289
290 /* load the missing pages from the network */
291 ret = read_cache_pages(mapping, pages, afs_page_filler, key);
292
293 _leave(" = %d [netting]", ret);
294 return ret;
295}
296
297/*
298 * write back a dirty page
299 */
300static int afs_launder_page(struct page *page)
301{
302 _enter("{%lu}", page->index);
303
304 return 0;
305}
306
307/*
308 * invalidate part or all of a page
309 * - release a page and clean up its private data if offset is 0 (indicating
310 * the entire page)
311 */
312static void afs_invalidatepage(struct page *page, unsigned int offset,
313 unsigned int length)
314{
315 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
316
317 _enter("{%lu},%u,%u", page->index, offset, length);
318
319 BUG_ON(!PageLocked(page));
320
321 /* we clean up only if the entire page is being invalidated */
322 if (offset == 0 && length == PAGE_SIZE) {
323#ifdef CONFIG_AFS_FSCACHE
324 if (PageFsCache(page)) {
325 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
326 fscache_wait_on_page_write(vnode->cache, page);
327 fscache_uncache_page(vnode->cache, page);
328 }
329#endif
330
331 if (PagePrivate(page)) {
332 if (wb && !PageWriteback(page)) {
333 set_page_private(page, 0);
334 afs_put_writeback(wb);
335 }
336
337 if (!page_private(page))
338 ClearPagePrivate(page);
339 }
340 }
341
342 _leave("");
343}
344
345/*
346 * release a page and clean up its private state if it's not busy
347 * - return true if the page can now be released, false if not
348 */
349static int afs_releasepage(struct page *page, gfp_t gfp_flags)
350{
351 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
352 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
353
354 _enter("{{%x:%u}[%lu],%lx},%x",
355 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
356 gfp_flags);
357
358 /* deny if page is being written to the cache and the caller hasn't
359 * elected to wait */
360#ifdef CONFIG_AFS_FSCACHE
361 if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
362 _leave(" = F [cache busy]");
363 return 0;
364 }
365#endif
366
367 if (PagePrivate(page)) {
368 if (wb) {
369 set_page_private(page, 0);
370 afs_put_writeback(wb);
371 }
372 ClearPagePrivate(page);
373 }
374
375 /* indicate that the page can be released */
376 _leave(" = T");
377 return 1;
378}