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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, | |
58fed94d | 33 | .flush = afs_flush, |
00d3b7a4 DH |
34 | .release = afs_release, |
35 | .llseek = generic_file_llseek, | |
aad4f8bb | 36 | .read_iter = generic_file_read_iter, |
50b5551d | 37 | .write_iter = afs_file_write, |
00d3b7a4 | 38 | .mmap = generic_file_readonly_mmap, |
5ffc4ef4 | 39 | .splice_read = generic_file_splice_read, |
31143d5d | 40 | .fsync = afs_fsync, |
e8d6c554 DH |
41 | .lock = afs_lock, |
42 | .flock = afs_flock, | |
00d3b7a4 DH |
43 | }; |
44 | ||
754661f1 | 45 | const struct inode_operations afs_file_inode_operations = { |
416351f2 | 46 | .getattr = afs_getattr, |
31143d5d | 47 | .setattr = afs_setattr, |
00d3b7a4 | 48 | .permission = afs_permission, |
d3e3b7ea | 49 | .listxattr = afs_listxattr, |
1da177e4 LT |
50 | }; |
51 | ||
f5e54d6e | 52 | const struct address_space_operations afs_fs_aops = { |
416351f2 | 53 | .readpage = afs_readpage, |
9b3f26c9 | 54 | .readpages = afs_readpages, |
31143d5d DH |
55 | .set_page_dirty = afs_set_page_dirty, |
56 | .launder_page = afs_launder_page, | |
416351f2 DH |
57 | .releasepage = afs_releasepage, |
58 | .invalidatepage = afs_invalidatepage, | |
15b4650e NP |
59 | .write_begin = afs_write_begin, |
60 | .write_end = afs_write_end, | |
31143d5d DH |
61 | .writepage = afs_writepage, |
62 | .writepages = afs_writepages, | |
1da177e4 LT |
63 | }; |
64 | ||
00d3b7a4 DH |
65 | /* |
66 | * open an AFS file or directory and attach a key to it | |
67 | */ | |
68 | int afs_open(struct inode *inode, struct file *file) | |
69 | { | |
70 | struct afs_vnode *vnode = AFS_FS_I(inode); | |
71 | struct key *key; | |
260a9803 | 72 | int ret; |
00d3b7a4 | 73 | |
416351f2 | 74 | _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode); |
00d3b7a4 DH |
75 | |
76 | key = afs_request_key(vnode->volume->cell); | |
77 | if (IS_ERR(key)) { | |
78 | _leave(" = %ld [key]", PTR_ERR(key)); | |
79 | return PTR_ERR(key); | |
80 | } | |
81 | ||
260a9803 DH |
82 | ret = afs_validate(vnode, key); |
83 | if (ret < 0) { | |
84 | _leave(" = %d [val]", ret); | |
85 | return ret; | |
86 | } | |
87 | ||
00d3b7a4 DH |
88 | file->private_data = key; |
89 | _leave(" = 0"); | |
90 | return 0; | |
91 | } | |
92 | ||
93 | /* | |
94 | * release an AFS file or directory and discard its key | |
95 | */ | |
96 | int afs_release(struct inode *inode, struct file *file) | |
97 | { | |
98 | struct afs_vnode *vnode = AFS_FS_I(inode); | |
99 | ||
416351f2 | 100 | _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode); |
00d3b7a4 DH |
101 | |
102 | key_put(file->private_data); | |
103 | _leave(" = 0"); | |
104 | return 0; | |
105 | } | |
106 | ||
196ee9cd DH |
107 | /* |
108 | * Dispose of a ref to a read record. | |
109 | */ | |
110 | void afs_put_read(struct afs_read *req) | |
111 | { | |
112 | int i; | |
113 | ||
114 | if (atomic_dec_and_test(&req->usage)) { | |
115 | for (i = 0; i < req->nr_pages; i++) | |
116 | if (req->pages[i]) | |
117 | put_page(req->pages[i]); | |
118 | kfree(req); | |
119 | } | |
120 | } | |
121 | ||
6566abdb | 122 | #ifdef CONFIG_AFS_FSCACHE |
1da177e4 LT |
123 | /* |
124 | * deal with notification that a page was read from the cache | |
125 | */ | |
9b3f26c9 DH |
126 | static void afs_file_readpage_read_complete(struct page *page, |
127 | void *data, | |
128 | int error) | |
1da177e4 | 129 | { |
9b3f26c9 | 130 | _enter("%p,%p,%d", page, data, error); |
1da177e4 | 131 | |
9b3f26c9 DH |
132 | /* if the read completes with an error, we just unlock the page and let |
133 | * the VM reissue the readpage */ | |
134 | if (!error) | |
1da177e4 LT |
135 | SetPageUptodate(page); |
136 | unlock_page(page); | |
ec26815a | 137 | } |
6566abdb | 138 | #endif |
1da177e4 | 139 | |
1da177e4 | 140 | /* |
f6d335c0 | 141 | * read page from file, directory or symlink, given a key to use |
1da177e4 | 142 | */ |
f6d335c0 | 143 | int afs_page_filler(void *data, struct page *page) |
1da177e4 | 144 | { |
f6d335c0 AV |
145 | struct inode *inode = page->mapping->host; |
146 | struct afs_vnode *vnode = AFS_FS_I(inode); | |
196ee9cd | 147 | struct afs_read *req; |
f6d335c0 | 148 | struct key *key = data; |
1da177e4 LT |
149 | int ret; |
150 | ||
00d3b7a4 | 151 | _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index); |
1da177e4 | 152 | |
cd7619d6 | 153 | BUG_ON(!PageLocked(page)); |
1da177e4 LT |
154 | |
155 | ret = -ESTALE; | |
08e0e7c8 | 156 | if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) |
1da177e4 LT |
157 | goto error; |
158 | ||
1da177e4 | 159 | /* is it cached? */ |
9b3f26c9 DH |
160 | #ifdef CONFIG_AFS_FSCACHE |
161 | ret = fscache_read_or_alloc_page(vnode->cache, | |
1da177e4 LT |
162 | page, |
163 | afs_file_readpage_read_complete, | |
164 | NULL, | |
165 | GFP_KERNEL); | |
166 | #else | |
167 | ret = -ENOBUFS; | |
168 | #endif | |
1da177e4 | 169 | switch (ret) { |
1da177e4 LT |
170 | /* read BIO submitted (page in cache) */ |
171 | case 0: | |
172 | break; | |
173 | ||
9b3f26c9 | 174 | /* page not yet cached */ |
1da177e4 | 175 | case -ENODATA: |
9b3f26c9 DH |
176 | _debug("cache said ENODATA"); |
177 | goto go_on; | |
178 | ||
179 | /* page will not be cached */ | |
180 | case -ENOBUFS: | |
181 | _debug("cache said ENOBUFS"); | |
1da177e4 | 182 | default: |
9b3f26c9 | 183 | go_on: |
196ee9cd DH |
184 | req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *), |
185 | GFP_KERNEL); | |
186 | if (!req) | |
187 | goto enomem; | |
188 | ||
6db3ac3c DH |
189 | /* We request a full page. If the page is a partial one at the |
190 | * end of the file, the server will return a short read and the | |
191 | * unmarshalling code will clear the unfilled space. | |
192 | */ | |
196ee9cd DH |
193 | atomic_set(&req->usage, 1); |
194 | req->pos = (loff_t)page->index << PAGE_SHIFT; | |
6db3ac3c | 195 | req->len = PAGE_SIZE; |
196ee9cd DH |
196 | req->nr_pages = 1; |
197 | req->pages[0] = page; | |
198 | get_page(page); | |
1da177e4 LT |
199 | |
200 | /* read the contents of the file from the server into the | |
201 | * page */ | |
196ee9cd DH |
202 | ret = afs_vnode_fetch_data(vnode, key, req); |
203 | afs_put_read(req); | |
1da177e4 | 204 | if (ret < 0) { |
08e0e7c8 | 205 | if (ret == -ENOENT) { |
1da177e4 LT |
206 | _debug("got NOENT from server" |
207 | " - marking file deleted and stale"); | |
08e0e7c8 | 208 | set_bit(AFS_VNODE_DELETED, &vnode->flags); |
1da177e4 LT |
209 | ret = -ESTALE; |
210 | } | |
9b3f26c9 DH |
211 | |
212 | #ifdef CONFIG_AFS_FSCACHE | |
213 | fscache_uncache_page(vnode->cache, page); | |
1da177e4 | 214 | #endif |
9b3f26c9 | 215 | BUG_ON(PageFsCache(page)); |
68ae849d DH |
216 | |
217 | if (ret == -EINTR || | |
218 | ret == -ENOMEM || | |
219 | ret == -ERESTARTSYS || | |
220 | ret == -EAGAIN) | |
221 | goto error; | |
222 | goto io_error; | |
1da177e4 LT |
223 | } |
224 | ||
225 | SetPageUptodate(page); | |
226 | ||
9b3f26c9 DH |
227 | /* send the page to the cache */ |
228 | #ifdef CONFIG_AFS_FSCACHE | |
229 | if (PageFsCache(page) && | |
230 | fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) { | |
231 | fscache_uncache_page(vnode->cache, page); | |
232 | BUG_ON(PageFsCache(page)); | |
1da177e4 | 233 | } |
1da177e4 | 234 | #endif |
9b3f26c9 | 235 | unlock_page(page); |
1da177e4 LT |
236 | } |
237 | ||
238 | _leave(" = 0"); | |
239 | return 0; | |
240 | ||
68ae849d DH |
241 | io_error: |
242 | SetPageError(page); | |
243 | goto error; | |
196ee9cd DH |
244 | enomem: |
245 | ret = -ENOMEM; | |
08e0e7c8 | 246 | error: |
1da177e4 | 247 | unlock_page(page); |
1da177e4 LT |
248 | _leave(" = %d", ret); |
249 | return ret; | |
ec26815a | 250 | } |
1da177e4 | 251 | |
f6d335c0 AV |
252 | /* |
253 | * read page from file, directory or symlink, given a file to nominate the key | |
254 | * to be used | |
255 | */ | |
256 | static int afs_readpage(struct file *file, struct page *page) | |
257 | { | |
258 | struct key *key; | |
259 | int ret; | |
260 | ||
261 | if (file) { | |
262 | key = file->private_data; | |
263 | ASSERT(key != NULL); | |
264 | ret = afs_page_filler(key, page); | |
265 | } else { | |
266 | struct inode *inode = page->mapping->host; | |
267 | key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell); | |
268 | if (IS_ERR(key)) { | |
269 | ret = PTR_ERR(key); | |
270 | } else { | |
271 | ret = afs_page_filler(key, page); | |
272 | key_put(key); | |
273 | } | |
274 | } | |
275 | return ret; | |
276 | } | |
277 | ||
91b467e0 DH |
278 | /* |
279 | * Make pages available as they're filled. | |
280 | */ | |
281 | static void afs_readpages_page_done(struct afs_call *call, struct afs_read *req) | |
282 | { | |
51c89e6a | 283 | #ifdef CONFIG_AFS_FSCACHE |
91b467e0 | 284 | struct afs_vnode *vnode = call->reply; |
51c89e6a | 285 | #endif |
91b467e0 DH |
286 | struct page *page = req->pages[req->index]; |
287 | ||
288 | req->pages[req->index] = NULL; | |
289 | SetPageUptodate(page); | |
290 | ||
291 | /* send the page to the cache */ | |
292 | #ifdef CONFIG_AFS_FSCACHE | |
293 | if (PageFsCache(page) && | |
294 | fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) { | |
295 | fscache_uncache_page(vnode->cache, page); | |
296 | BUG_ON(PageFsCache(page)); | |
297 | } | |
298 | #endif | |
299 | unlock_page(page); | |
300 | put_page(page); | |
301 | } | |
302 | ||
303 | /* | |
304 | * Read a contiguous set of pages. | |
305 | */ | |
306 | static int afs_readpages_one(struct file *file, struct address_space *mapping, | |
307 | struct list_head *pages) | |
308 | { | |
309 | struct afs_vnode *vnode = AFS_FS_I(mapping->host); | |
310 | struct afs_read *req; | |
311 | struct list_head *p; | |
312 | struct page *first, *page; | |
313 | struct key *key = file->private_data; | |
314 | pgoff_t index; | |
315 | int ret, n, i; | |
316 | ||
317 | /* Count the number of contiguous pages at the front of the list. Note | |
318 | * that the list goes prev-wards rather than next-wards. | |
319 | */ | |
320 | first = list_entry(pages->prev, struct page, lru); | |
321 | index = first->index + 1; | |
322 | n = 1; | |
323 | for (p = first->lru.prev; p != pages; p = p->prev) { | |
324 | page = list_entry(p, struct page, lru); | |
325 | if (page->index != index) | |
326 | break; | |
327 | index++; | |
328 | n++; | |
329 | } | |
330 | ||
331 | req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *) * n, | |
332 | GFP_NOFS); | |
333 | if (!req) | |
334 | return -ENOMEM; | |
335 | ||
336 | atomic_set(&req->usage, 1); | |
337 | req->page_done = afs_readpages_page_done; | |
338 | req->pos = first->index; | |
339 | req->pos <<= PAGE_SHIFT; | |
340 | ||
341 | /* Transfer the pages to the request. We add them in until one fails | |
342 | * to add to the LRU and then we stop (as that'll make a hole in the | |
343 | * contiguous run. | |
344 | * | |
345 | * Note that it's possible for the file size to change whilst we're | |
346 | * doing this, but we rely on the server returning less than we asked | |
347 | * for if the file shrank. We also rely on this to deal with a partial | |
348 | * page at the end of the file. | |
349 | */ | |
350 | do { | |
351 | page = list_entry(pages->prev, struct page, lru); | |
352 | list_del(&page->lru); | |
353 | index = page->index; | |
354 | if (add_to_page_cache_lru(page, mapping, index, | |
355 | readahead_gfp_mask(mapping))) { | |
356 | #ifdef CONFIG_AFS_FSCACHE | |
357 | fscache_uncache_page(vnode->cache, page); | |
358 | #endif | |
359 | put_page(page); | |
360 | break; | |
361 | } | |
362 | ||
363 | req->pages[req->nr_pages++] = page; | |
364 | req->len += PAGE_SIZE; | |
365 | } while (req->nr_pages < n); | |
366 | ||
367 | if (req->nr_pages == 0) { | |
368 | kfree(req); | |
369 | return 0; | |
370 | } | |
371 | ||
372 | ret = afs_vnode_fetch_data(vnode, key, req); | |
373 | if (ret < 0) | |
374 | goto error; | |
375 | ||
376 | task_io_account_read(PAGE_SIZE * req->nr_pages); | |
377 | afs_put_read(req); | |
378 | return 0; | |
379 | ||
380 | error: | |
381 | if (ret == -ENOENT) { | |
382 | _debug("got NOENT from server" | |
383 | " - marking file deleted and stale"); | |
384 | set_bit(AFS_VNODE_DELETED, &vnode->flags); | |
385 | ret = -ESTALE; | |
386 | } | |
387 | ||
388 | for (i = 0; i < req->nr_pages; i++) { | |
389 | page = req->pages[i]; | |
390 | if (page) { | |
391 | #ifdef CONFIG_AFS_FSCACHE | |
392 | fscache_uncache_page(vnode->cache, page); | |
393 | #endif | |
394 | SetPageError(page); | |
395 | unlock_page(page); | |
396 | } | |
397 | } | |
398 | ||
399 | afs_put_read(req); | |
400 | return ret; | |
401 | } | |
402 | ||
1da177e4 | 403 | /* |
9b3f26c9 | 404 | * read a set of pages |
1da177e4 | 405 | */ |
9b3f26c9 DH |
406 | static int afs_readpages(struct file *file, struct address_space *mapping, |
407 | struct list_head *pages, unsigned nr_pages) | |
1da177e4 | 408 | { |
f6d335c0 | 409 | struct key *key = file->private_data; |
9b3f26c9 DH |
410 | struct afs_vnode *vnode; |
411 | int ret = 0; | |
1da177e4 | 412 | |
f6d335c0 AV |
413 | _enter("{%d},{%lu},,%d", |
414 | key_serial(key), mapping->host->i_ino, nr_pages); | |
415 | ||
416 | ASSERT(key != NULL); | |
1da177e4 | 417 | |
9b3f26c9 | 418 | vnode = AFS_FS_I(mapping->host); |
ad2a8e60 | 419 | if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) { |
9b3f26c9 DH |
420 | _leave(" = -ESTALE"); |
421 | return -ESTALE; | |
422 | } | |
1da177e4 | 423 | |
9b3f26c9 DH |
424 | /* attempt to read as many of the pages as possible */ |
425 | #ifdef CONFIG_AFS_FSCACHE | |
426 | ret = fscache_read_or_alloc_pages(vnode->cache, | |
427 | mapping, | |
428 | pages, | |
429 | &nr_pages, | |
430 | afs_file_readpage_read_complete, | |
431 | NULL, | |
432 | mapping_gfp_mask(mapping)); | |
433 | #else | |
434 | ret = -ENOBUFS; | |
435 | #endif | |
436 | ||
437 | switch (ret) { | |
438 | /* all pages are being read from the cache */ | |
439 | case 0: | |
440 | BUG_ON(!list_empty(pages)); | |
441 | BUG_ON(nr_pages != 0); | |
442 | _leave(" = 0 [reading all]"); | |
443 | return 0; | |
444 | ||
445 | /* there were pages that couldn't be read from the cache */ | |
446 | case -ENODATA: | |
447 | case -ENOBUFS: | |
448 | break; | |
449 | ||
450 | /* other error */ | |
451 | default: | |
452 | _leave(" = %d", ret); | |
453 | return ret; | |
1da177e4 LT |
454 | } |
455 | ||
91b467e0 DH |
456 | while (!list_empty(pages)) { |
457 | ret = afs_readpages_one(file, mapping, pages); | |
458 | if (ret < 0) | |
459 | break; | |
460 | } | |
9b3f26c9 DH |
461 | |
462 | _leave(" = %d [netting]", ret); | |
463 | return ret; | |
ec26815a | 464 | } |
1da177e4 | 465 | |
31143d5d DH |
466 | /* |
467 | * write back a dirty page | |
468 | */ | |
469 | static int afs_launder_page(struct page *page) | |
470 | { | |
471 | _enter("{%lu}", page->index); | |
472 | ||
473 | return 0; | |
474 | } | |
475 | ||
1da177e4 | 476 | /* |
9b3f26c9 DH |
477 | * invalidate part or all of a page |
478 | * - release a page and clean up its private data if offset is 0 (indicating | |
479 | * the entire page) | |
480 | */ | |
d47992f8 LC |
481 | static void afs_invalidatepage(struct page *page, unsigned int offset, |
482 | unsigned int length) | |
9b3f26c9 DH |
483 | { |
484 | struct afs_writeback *wb = (struct afs_writeback *) page_private(page); | |
485 | ||
d47992f8 | 486 | _enter("{%lu},%u,%u", page->index, offset, length); |
9b3f26c9 DH |
487 | |
488 | BUG_ON(!PageLocked(page)); | |
489 | ||
490 | /* we clean up only if the entire page is being invalidated */ | |
09cbfeaf | 491 | if (offset == 0 && length == PAGE_SIZE) { |
9b3f26c9 DH |
492 | #ifdef CONFIG_AFS_FSCACHE |
493 | if (PageFsCache(page)) { | |
494 | struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); | |
495 | fscache_wait_on_page_write(vnode->cache, page); | |
496 | fscache_uncache_page(vnode->cache, page); | |
9b3f26c9 DH |
497 | } |
498 | #endif | |
499 | ||
500 | if (PagePrivate(page)) { | |
501 | if (wb && !PageWriteback(page)) { | |
502 | set_page_private(page, 0); | |
503 | afs_put_writeback(wb); | |
504 | } | |
505 | ||
506 | if (!page_private(page)) | |
507 | ClearPagePrivate(page); | |
508 | } | |
509 | } | |
510 | ||
511 | _leave(""); | |
512 | } | |
513 | ||
514 | /* | |
515 | * release a page and clean up its private state if it's not busy | |
516 | * - return true if the page can now be released, false if not | |
1da177e4 | 517 | */ |
416351f2 | 518 | static int afs_releasepage(struct page *page, gfp_t gfp_flags) |
1da177e4 | 519 | { |
9b3f26c9 | 520 | struct afs_writeback *wb = (struct afs_writeback *) page_private(page); |
416351f2 | 521 | struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); |
1da177e4 | 522 | |
416351f2 DH |
523 | _enter("{{%x:%u}[%lu],%lx},%x", |
524 | vnode->fid.vid, vnode->fid.vnode, page->index, page->flags, | |
525 | gfp_flags); | |
1da177e4 | 526 | |
9b3f26c9 DH |
527 | /* deny if page is being written to the cache and the caller hasn't |
528 | * elected to wait */ | |
529 | #ifdef CONFIG_AFS_FSCACHE | |
201a1542 DH |
530 | if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) { |
531 | _leave(" = F [cache busy]"); | |
532 | return 0; | |
9b3f26c9 DH |
533 | } |
534 | #endif | |
535 | ||
1da177e4 | 536 | if (PagePrivate(page)) { |
9b3f26c9 DH |
537 | if (wb) { |
538 | set_page_private(page, 0); | |
539 | afs_put_writeback(wb); | |
540 | } | |
1da177e4 | 541 | ClearPagePrivate(page); |
1da177e4 LT |
542 | } |
543 | ||
9b3f26c9 DH |
544 | /* indicate that the page can be released */ |
545 | _leave(" = T"); | |
546 | return 1; | |
ec26815a | 547 | } |