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Commit | Line | Data |
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08e0e7c8 | 1 | /* AFS filesystem file handling |
1da177e4 | 2 | * |
08e0e7c8 | 3 | * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved. |
1da177e4 LT |
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> | |
1da177e4 LT |
15 | #include <linux/fs.h> |
16 | #include <linux/pagemap.h> | |
31143d5d | 17 | #include <linux/writeback.h> |
5a0e3ad6 | 18 | #include <linux/gfp.h> |
91b467e0 | 19 | #include <linux/task_io_accounting_ops.h> |
1da177e4 LT |
20 | #include "internal.h" |
21 | ||
416351f2 | 22 | static int afs_readpage(struct file *file, struct page *page); |
d47992f8 LC |
23 | static void afs_invalidatepage(struct page *page, unsigned int offset, |
24 | unsigned int length); | |
416351f2 | 25 | static int afs_releasepage(struct page *page, gfp_t gfp_flags); |
31143d5d | 26 | static int afs_launder_page(struct page *page); |
1da177e4 | 27 | |
9b3f26c9 DH |
28 | static int afs_readpages(struct file *filp, struct address_space *mapping, |
29 | struct list_head *pages, unsigned nr_pages); | |
30 | ||
00d3b7a4 DH |
31 | const struct file_operations afs_file_operations = { |
32 | .open = afs_open, | |
33 | .release = afs_release, | |
34 | .llseek = generic_file_llseek, | |
aad4f8bb | 35 | .read_iter = generic_file_read_iter, |
50b5551d | 36 | .write_iter = afs_file_write, |
00d3b7a4 | 37 | .mmap = generic_file_readonly_mmap, |
5ffc4ef4 | 38 | .splice_read = generic_file_splice_read, |
31143d5d | 39 | .fsync = afs_fsync, |
e8d6c554 DH |
40 | .lock = afs_lock, |
41 | .flock = afs_flock, | |
00d3b7a4 DH |
42 | }; |
43 | ||
754661f1 | 44 | const struct inode_operations afs_file_inode_operations = { |
416351f2 | 45 | .getattr = afs_getattr, |
31143d5d | 46 | .setattr = afs_setattr, |
00d3b7a4 | 47 | .permission = afs_permission, |
1da177e4 LT |
48 | }; |
49 | ||
f5e54d6e | 50 | const struct address_space_operations afs_fs_aops = { |
416351f2 | 51 | .readpage = afs_readpage, |
9b3f26c9 | 52 | .readpages = afs_readpages, |
31143d5d DH |
53 | .set_page_dirty = afs_set_page_dirty, |
54 | .launder_page = afs_launder_page, | |
416351f2 DH |
55 | .releasepage = afs_releasepage, |
56 | .invalidatepage = afs_invalidatepage, | |
15b4650e NP |
57 | .write_begin = afs_write_begin, |
58 | .write_end = afs_write_end, | |
31143d5d DH |
59 | .writepage = afs_writepage, |
60 | .writepages = afs_writepages, | |
1da177e4 LT |
61 | }; |
62 | ||
00d3b7a4 DH |
63 | /* |
64 | * open an AFS file or directory and attach a key to it | |
65 | */ | |
66 | int afs_open(struct inode *inode, struct file *file) | |
67 | { | |
68 | struct afs_vnode *vnode = AFS_FS_I(inode); | |
69 | struct key *key; | |
260a9803 | 70 | int ret; |
00d3b7a4 | 71 | |
416351f2 | 72 | _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode); |
00d3b7a4 DH |
73 | |
74 | key = afs_request_key(vnode->volume->cell); | |
75 | if (IS_ERR(key)) { | |
76 | _leave(" = %ld [key]", PTR_ERR(key)); | |
77 | return PTR_ERR(key); | |
78 | } | |
79 | ||
260a9803 DH |
80 | ret = afs_validate(vnode, key); |
81 | if (ret < 0) { | |
82 | _leave(" = %d [val]", ret); | |
83 | return ret; | |
84 | } | |
85 | ||
00d3b7a4 DH |
86 | file->private_data = key; |
87 | _leave(" = 0"); | |
88 | return 0; | |
89 | } | |
90 | ||
91 | /* | |
92 | * release an AFS file or directory and discard its key | |
93 | */ | |
94 | int afs_release(struct inode *inode, struct file *file) | |
95 | { | |
96 | struct afs_vnode *vnode = AFS_FS_I(inode); | |
97 | ||
416351f2 | 98 | _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode); |
00d3b7a4 DH |
99 | |
100 | key_put(file->private_data); | |
101 | _leave(" = 0"); | |
102 | return 0; | |
103 | } | |
104 | ||
196ee9cd DH |
105 | /* |
106 | * Dispose of a ref to a read record. | |
107 | */ | |
108 | void afs_put_read(struct afs_read *req) | |
109 | { | |
110 | int i; | |
111 | ||
112 | if (atomic_dec_and_test(&req->usage)) { | |
113 | for (i = 0; i < req->nr_pages; i++) | |
114 | if (req->pages[i]) | |
115 | put_page(req->pages[i]); | |
116 | kfree(req); | |
117 | } | |
118 | } | |
119 | ||
6566abdb | 120 | #ifdef CONFIG_AFS_FSCACHE |
1da177e4 LT |
121 | /* |
122 | * deal with notification that a page was read from the cache | |
123 | */ | |
9b3f26c9 DH |
124 | static void afs_file_readpage_read_complete(struct page *page, |
125 | void *data, | |
126 | int error) | |
1da177e4 | 127 | { |
9b3f26c9 | 128 | _enter("%p,%p,%d", page, data, error); |
1da177e4 | 129 | |
9b3f26c9 DH |
130 | /* if the read completes with an error, we just unlock the page and let |
131 | * the VM reissue the readpage */ | |
132 | if (!error) | |
1da177e4 LT |
133 | SetPageUptodate(page); |
134 | unlock_page(page); | |
ec26815a | 135 | } |
6566abdb | 136 | #endif |
1da177e4 | 137 | |
1da177e4 | 138 | /* |
f6d335c0 | 139 | * read page from file, directory or symlink, given a key to use |
1da177e4 | 140 | */ |
f6d335c0 | 141 | int afs_page_filler(void *data, struct page *page) |
1da177e4 | 142 | { |
f6d335c0 AV |
143 | struct inode *inode = page->mapping->host; |
144 | struct afs_vnode *vnode = AFS_FS_I(inode); | |
196ee9cd | 145 | struct afs_read *req; |
f6d335c0 | 146 | struct key *key = data; |
1da177e4 LT |
147 | int ret; |
148 | ||
00d3b7a4 | 149 | _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index); |
1da177e4 | 150 | |
cd7619d6 | 151 | BUG_ON(!PageLocked(page)); |
1da177e4 LT |
152 | |
153 | ret = -ESTALE; | |
08e0e7c8 | 154 | if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) |
1da177e4 LT |
155 | goto error; |
156 | ||
1da177e4 | 157 | /* is it cached? */ |
9b3f26c9 DH |
158 | #ifdef CONFIG_AFS_FSCACHE |
159 | ret = fscache_read_or_alloc_page(vnode->cache, | |
1da177e4 LT |
160 | page, |
161 | afs_file_readpage_read_complete, | |
162 | NULL, | |
163 | GFP_KERNEL); | |
164 | #else | |
165 | ret = -ENOBUFS; | |
166 | #endif | |
1da177e4 | 167 | switch (ret) { |
1da177e4 LT |
168 | /* read BIO submitted (page in cache) */ |
169 | case 0: | |
170 | break; | |
171 | ||
9b3f26c9 | 172 | /* page not yet cached */ |
1da177e4 | 173 | case -ENODATA: |
9b3f26c9 DH |
174 | _debug("cache said ENODATA"); |
175 | goto go_on; | |
176 | ||
177 | /* page will not be cached */ | |
178 | case -ENOBUFS: | |
179 | _debug("cache said ENOBUFS"); | |
1da177e4 | 180 | default: |
9b3f26c9 | 181 | go_on: |
196ee9cd DH |
182 | req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *), |
183 | GFP_KERNEL); | |
184 | if (!req) | |
185 | goto enomem; | |
186 | ||
187 | atomic_set(&req->usage, 1); | |
188 | req->pos = (loff_t)page->index << PAGE_SHIFT; | |
189 | req->len = min_t(size_t, i_size_read(inode) - req->pos, | |
190 | PAGE_SIZE); | |
191 | req->nr_pages = 1; | |
192 | req->pages[0] = page; | |
193 | get_page(page); | |
1da177e4 LT |
194 | |
195 | /* read the contents of the file from the server into the | |
196 | * page */ | |
196ee9cd DH |
197 | ret = afs_vnode_fetch_data(vnode, key, req); |
198 | afs_put_read(req); | |
1da177e4 | 199 | if (ret < 0) { |
08e0e7c8 | 200 | if (ret == -ENOENT) { |
1da177e4 LT |
201 | _debug("got NOENT from server" |
202 | " - marking file deleted and stale"); | |
08e0e7c8 | 203 | set_bit(AFS_VNODE_DELETED, &vnode->flags); |
1da177e4 LT |
204 | ret = -ESTALE; |
205 | } | |
9b3f26c9 DH |
206 | |
207 | #ifdef CONFIG_AFS_FSCACHE | |
208 | fscache_uncache_page(vnode->cache, page); | |
1da177e4 | 209 | #endif |
9b3f26c9 | 210 | BUG_ON(PageFsCache(page)); |
1da177e4 LT |
211 | goto error; |
212 | } | |
213 | ||
214 | SetPageUptodate(page); | |
215 | ||
9b3f26c9 DH |
216 | /* send the page to the cache */ |
217 | #ifdef CONFIG_AFS_FSCACHE | |
218 | if (PageFsCache(page) && | |
219 | fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) { | |
220 | fscache_uncache_page(vnode->cache, page); | |
221 | BUG_ON(PageFsCache(page)); | |
1da177e4 | 222 | } |
1da177e4 | 223 | #endif |
9b3f26c9 | 224 | unlock_page(page); |
1da177e4 LT |
225 | } |
226 | ||
227 | _leave(" = 0"); | |
228 | return 0; | |
229 | ||
196ee9cd DH |
230 | enomem: |
231 | ret = -ENOMEM; | |
08e0e7c8 | 232 | error: |
1da177e4 LT |
233 | SetPageError(page); |
234 | unlock_page(page); | |
1da177e4 LT |
235 | _leave(" = %d", ret); |
236 | return ret; | |
ec26815a | 237 | } |
1da177e4 | 238 | |
f6d335c0 AV |
239 | /* |
240 | * read page from file, directory or symlink, given a file to nominate the key | |
241 | * to be used | |
242 | */ | |
243 | static int afs_readpage(struct file *file, struct page *page) | |
244 | { | |
245 | struct key *key; | |
246 | int ret; | |
247 | ||
248 | if (file) { | |
249 | key = file->private_data; | |
250 | ASSERT(key != NULL); | |
251 | ret = afs_page_filler(key, page); | |
252 | } else { | |
253 | struct inode *inode = page->mapping->host; | |
254 | key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell); | |
255 | if (IS_ERR(key)) { | |
256 | ret = PTR_ERR(key); | |
257 | } else { | |
258 | ret = afs_page_filler(key, page); | |
259 | key_put(key); | |
260 | } | |
261 | } | |
262 | return ret; | |
263 | } | |
264 | ||
91b467e0 DH |
265 | /* |
266 | * Make pages available as they're filled. | |
267 | */ | |
268 | static void afs_readpages_page_done(struct afs_call *call, struct afs_read *req) | |
269 | { | |
51c89e6a | 270 | #ifdef CONFIG_AFS_FSCACHE |
91b467e0 | 271 | struct afs_vnode *vnode = call->reply; |
51c89e6a | 272 | #endif |
91b467e0 DH |
273 | struct page *page = req->pages[req->index]; |
274 | ||
275 | req->pages[req->index] = NULL; | |
276 | SetPageUptodate(page); | |
277 | ||
278 | /* send the page to the cache */ | |
279 | #ifdef CONFIG_AFS_FSCACHE | |
280 | if (PageFsCache(page) && | |
281 | fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) { | |
282 | fscache_uncache_page(vnode->cache, page); | |
283 | BUG_ON(PageFsCache(page)); | |
284 | } | |
285 | #endif | |
286 | unlock_page(page); | |
287 | put_page(page); | |
288 | } | |
289 | ||
290 | /* | |
291 | * Read a contiguous set of pages. | |
292 | */ | |
293 | static int afs_readpages_one(struct file *file, struct address_space *mapping, | |
294 | struct list_head *pages) | |
295 | { | |
296 | struct afs_vnode *vnode = AFS_FS_I(mapping->host); | |
297 | struct afs_read *req; | |
298 | struct list_head *p; | |
299 | struct page *first, *page; | |
300 | struct key *key = file->private_data; | |
301 | pgoff_t index; | |
302 | int ret, n, i; | |
303 | ||
304 | /* Count the number of contiguous pages at the front of the list. Note | |
305 | * that the list goes prev-wards rather than next-wards. | |
306 | */ | |
307 | first = list_entry(pages->prev, struct page, lru); | |
308 | index = first->index + 1; | |
309 | n = 1; | |
310 | for (p = first->lru.prev; p != pages; p = p->prev) { | |
311 | page = list_entry(p, struct page, lru); | |
312 | if (page->index != index) | |
313 | break; | |
314 | index++; | |
315 | n++; | |
316 | } | |
317 | ||
318 | req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *) * n, | |
319 | GFP_NOFS); | |
320 | if (!req) | |
321 | return -ENOMEM; | |
322 | ||
323 | atomic_set(&req->usage, 1); | |
324 | req->page_done = afs_readpages_page_done; | |
325 | req->pos = first->index; | |
326 | req->pos <<= PAGE_SHIFT; | |
327 | ||
328 | /* Transfer the pages to the request. We add them in until one fails | |
329 | * to add to the LRU and then we stop (as that'll make a hole in the | |
330 | * contiguous run. | |
331 | * | |
332 | * Note that it's possible for the file size to change whilst we're | |
333 | * doing this, but we rely on the server returning less than we asked | |
334 | * for if the file shrank. We also rely on this to deal with a partial | |
335 | * page at the end of the file. | |
336 | */ | |
337 | do { | |
338 | page = list_entry(pages->prev, struct page, lru); | |
339 | list_del(&page->lru); | |
340 | index = page->index; | |
341 | if (add_to_page_cache_lru(page, mapping, index, | |
342 | readahead_gfp_mask(mapping))) { | |
343 | #ifdef CONFIG_AFS_FSCACHE | |
344 | fscache_uncache_page(vnode->cache, page); | |
345 | #endif | |
346 | put_page(page); | |
347 | break; | |
348 | } | |
349 | ||
350 | req->pages[req->nr_pages++] = page; | |
351 | req->len += PAGE_SIZE; | |
352 | } while (req->nr_pages < n); | |
353 | ||
354 | if (req->nr_pages == 0) { | |
355 | kfree(req); | |
356 | return 0; | |
357 | } | |
358 | ||
359 | ret = afs_vnode_fetch_data(vnode, key, req); | |
360 | if (ret < 0) | |
361 | goto error; | |
362 | ||
363 | task_io_account_read(PAGE_SIZE * req->nr_pages); | |
364 | afs_put_read(req); | |
365 | return 0; | |
366 | ||
367 | error: | |
368 | if (ret == -ENOENT) { | |
369 | _debug("got NOENT from server" | |
370 | " - marking file deleted and stale"); | |
371 | set_bit(AFS_VNODE_DELETED, &vnode->flags); | |
372 | ret = -ESTALE; | |
373 | } | |
374 | ||
375 | for (i = 0; i < req->nr_pages; i++) { | |
376 | page = req->pages[i]; | |
377 | if (page) { | |
378 | #ifdef CONFIG_AFS_FSCACHE | |
379 | fscache_uncache_page(vnode->cache, page); | |
380 | #endif | |
381 | SetPageError(page); | |
382 | unlock_page(page); | |
383 | } | |
384 | } | |
385 | ||
386 | afs_put_read(req); | |
387 | return ret; | |
388 | } | |
389 | ||
1da177e4 | 390 | /* |
9b3f26c9 | 391 | * read a set of pages |
1da177e4 | 392 | */ |
9b3f26c9 DH |
393 | static int afs_readpages(struct file *file, struct address_space *mapping, |
394 | struct list_head *pages, unsigned nr_pages) | |
1da177e4 | 395 | { |
f6d335c0 | 396 | struct key *key = file->private_data; |
9b3f26c9 DH |
397 | struct afs_vnode *vnode; |
398 | int ret = 0; | |
1da177e4 | 399 | |
f6d335c0 AV |
400 | _enter("{%d},{%lu},,%d", |
401 | key_serial(key), mapping->host->i_ino, nr_pages); | |
402 | ||
403 | ASSERT(key != NULL); | |
1da177e4 | 404 | |
9b3f26c9 | 405 | vnode = AFS_FS_I(mapping->host); |
ad2a8e60 | 406 | if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) { |
9b3f26c9 DH |
407 | _leave(" = -ESTALE"); |
408 | return -ESTALE; | |
409 | } | |
1da177e4 | 410 | |
9b3f26c9 DH |
411 | /* attempt to read as many of the pages as possible */ |
412 | #ifdef CONFIG_AFS_FSCACHE | |
413 | ret = fscache_read_or_alloc_pages(vnode->cache, | |
414 | mapping, | |
415 | pages, | |
416 | &nr_pages, | |
417 | afs_file_readpage_read_complete, | |
418 | NULL, | |
419 | mapping_gfp_mask(mapping)); | |
420 | #else | |
421 | ret = -ENOBUFS; | |
422 | #endif | |
423 | ||
424 | switch (ret) { | |
425 | /* all pages are being read from the cache */ | |
426 | case 0: | |
427 | BUG_ON(!list_empty(pages)); | |
428 | BUG_ON(nr_pages != 0); | |
429 | _leave(" = 0 [reading all]"); | |
430 | return 0; | |
431 | ||
432 | /* there were pages that couldn't be read from the cache */ | |
433 | case -ENODATA: | |
434 | case -ENOBUFS: | |
435 | break; | |
436 | ||
437 | /* other error */ | |
438 | default: | |
439 | _leave(" = %d", ret); | |
440 | return ret; | |
1da177e4 LT |
441 | } |
442 | ||
91b467e0 DH |
443 | while (!list_empty(pages)) { |
444 | ret = afs_readpages_one(file, mapping, pages); | |
445 | if (ret < 0) | |
446 | break; | |
447 | } | |
9b3f26c9 DH |
448 | |
449 | _leave(" = %d [netting]", ret); | |
450 | return ret; | |
ec26815a | 451 | } |
1da177e4 | 452 | |
31143d5d DH |
453 | /* |
454 | * write back a dirty page | |
455 | */ | |
456 | static int afs_launder_page(struct page *page) | |
457 | { | |
458 | _enter("{%lu}", page->index); | |
459 | ||
460 | return 0; | |
461 | } | |
462 | ||
1da177e4 | 463 | /* |
9b3f26c9 DH |
464 | * invalidate part or all of a page |
465 | * - release a page and clean up its private data if offset is 0 (indicating | |
466 | * the entire page) | |
467 | */ | |
d47992f8 LC |
468 | static void afs_invalidatepage(struct page *page, unsigned int offset, |
469 | unsigned int length) | |
9b3f26c9 DH |
470 | { |
471 | struct afs_writeback *wb = (struct afs_writeback *) page_private(page); | |
472 | ||
d47992f8 | 473 | _enter("{%lu},%u,%u", page->index, offset, length); |
9b3f26c9 DH |
474 | |
475 | BUG_ON(!PageLocked(page)); | |
476 | ||
477 | /* we clean up only if the entire page is being invalidated */ | |
09cbfeaf | 478 | if (offset == 0 && length == PAGE_SIZE) { |
9b3f26c9 DH |
479 | #ifdef CONFIG_AFS_FSCACHE |
480 | if (PageFsCache(page)) { | |
481 | struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); | |
482 | fscache_wait_on_page_write(vnode->cache, page); | |
483 | fscache_uncache_page(vnode->cache, page); | |
9b3f26c9 DH |
484 | } |
485 | #endif | |
486 | ||
487 | if (PagePrivate(page)) { | |
488 | if (wb && !PageWriteback(page)) { | |
489 | set_page_private(page, 0); | |
490 | afs_put_writeback(wb); | |
491 | } | |
492 | ||
493 | if (!page_private(page)) | |
494 | ClearPagePrivate(page); | |
495 | } | |
496 | } | |
497 | ||
498 | _leave(""); | |
499 | } | |
500 | ||
501 | /* | |
502 | * release a page and clean up its private state if it's not busy | |
503 | * - return true if the page can now be released, false if not | |
1da177e4 | 504 | */ |
416351f2 | 505 | static int afs_releasepage(struct page *page, gfp_t gfp_flags) |
1da177e4 | 506 | { |
9b3f26c9 | 507 | struct afs_writeback *wb = (struct afs_writeback *) page_private(page); |
416351f2 | 508 | struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); |
1da177e4 | 509 | |
416351f2 DH |
510 | _enter("{{%x:%u}[%lu],%lx},%x", |
511 | vnode->fid.vid, vnode->fid.vnode, page->index, page->flags, | |
512 | gfp_flags); | |
1da177e4 | 513 | |
9b3f26c9 DH |
514 | /* deny if page is being written to the cache and the caller hasn't |
515 | * elected to wait */ | |
516 | #ifdef CONFIG_AFS_FSCACHE | |
201a1542 DH |
517 | if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) { |
518 | _leave(" = F [cache busy]"); | |
519 | return 0; | |
9b3f26c9 DH |
520 | } |
521 | #endif | |
522 | ||
1da177e4 | 523 | if (PagePrivate(page)) { |
9b3f26c9 DH |
524 | if (wb) { |
525 | set_page_private(page, 0); | |
526 | afs_put_writeback(wb); | |
527 | } | |
1da177e4 | 528 | ClearPagePrivate(page); |
1da177e4 LT |
529 | } |
530 | ||
9b3f26c9 DH |
531 | /* indicate that the page can be released */ |
532 | _leave(" = T"); | |
533 | return 1; | |
ec26815a | 534 | } |