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/slab.h> |
16 | #include <linux/fs.h> | |
17 | #include <linux/pagemap.h> | |
31143d5d | 18 | #include <linux/writeback.h> |
1da177e4 LT |
19 | #include "internal.h" |
20 | ||
416351f2 DH |
21 | static int afs_readpage(struct file *file, struct page *page); |
22 | static void afs_invalidatepage(struct page *page, unsigned long offset); | |
23 | static int afs_releasepage(struct page *page, gfp_t gfp_flags); | |
31143d5d | 24 | static int afs_launder_page(struct page *page); |
1da177e4 | 25 | |
9b3f26c9 DH |
26 | static int afs_readpages(struct file *filp, struct address_space *mapping, |
27 | struct list_head *pages, unsigned nr_pages); | |
28 | ||
00d3b7a4 DH |
29 | const struct file_operations afs_file_operations = { |
30 | .open = afs_open, | |
31 | .release = afs_release, | |
32 | .llseek = generic_file_llseek, | |
33 | .read = do_sync_read, | |
31143d5d | 34 | .write = do_sync_write, |
00d3b7a4 | 35 | .aio_read = generic_file_aio_read, |
31143d5d | 36 | .aio_write = 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 | ||
6566abdb | 105 | #ifdef CONFIG_AFS_FSCACHE |
1da177e4 LT |
106 | /* |
107 | * deal with notification that a page was read from the cache | |
108 | */ | |
9b3f26c9 DH |
109 | static void afs_file_readpage_read_complete(struct page *page, |
110 | void *data, | |
111 | int error) | |
1da177e4 | 112 | { |
9b3f26c9 | 113 | _enter("%p,%p,%d", page, data, error); |
1da177e4 | 114 | |
9b3f26c9 DH |
115 | /* if the read completes with an error, we just unlock the page and let |
116 | * the VM reissue the readpage */ | |
117 | if (!error) | |
1da177e4 LT |
118 | SetPageUptodate(page); |
119 | unlock_page(page); | |
ec26815a | 120 | } |
6566abdb | 121 | #endif |
1da177e4 | 122 | |
1da177e4 | 123 | /* |
416351f2 | 124 | * AFS read page from file, directory or symlink |
1da177e4 | 125 | */ |
416351f2 | 126 | static int afs_readpage(struct file *file, struct page *page) |
1da177e4 | 127 | { |
1da177e4 LT |
128 | struct afs_vnode *vnode; |
129 | struct inode *inode; | |
00d3b7a4 | 130 | struct key *key; |
08e0e7c8 DH |
131 | size_t len; |
132 | off_t offset; | |
1da177e4 LT |
133 | int ret; |
134 | ||
135 | inode = page->mapping->host; | |
136 | ||
9886e836 DH |
137 | if (file) { |
138 | key = file->private_data; | |
139 | ASSERT(key != NULL); | |
140 | } else { | |
141 | key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell); | |
142 | if (IS_ERR(key)) { | |
143 | ret = PTR_ERR(key); | |
144 | goto error_nokey; | |
145 | } | |
146 | } | |
00d3b7a4 DH |
147 | |
148 | _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index); | |
1da177e4 LT |
149 | |
150 | vnode = AFS_FS_I(inode); | |
151 | ||
cd7619d6 | 152 | BUG_ON(!PageLocked(page)); |
1da177e4 LT |
153 | |
154 | ret = -ESTALE; | |
08e0e7c8 | 155 | if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) |
1da177e4 LT |
156 | goto error; |
157 | ||
1da177e4 | 158 | /* is it cached? */ |
9b3f26c9 DH |
159 | #ifdef CONFIG_AFS_FSCACHE |
160 | ret = fscache_read_or_alloc_page(vnode->cache, | |
1da177e4 LT |
161 | page, |
162 | afs_file_readpage_read_complete, | |
163 | NULL, | |
164 | GFP_KERNEL); | |
165 | #else | |
166 | ret = -ENOBUFS; | |
167 | #endif | |
1da177e4 | 168 | switch (ret) { |
1da177e4 LT |
169 | /* read BIO submitted (page in cache) */ |
170 | case 0: | |
171 | break; | |
172 | ||
9b3f26c9 | 173 | /* page not yet cached */ |
1da177e4 | 174 | case -ENODATA: |
9b3f26c9 DH |
175 | _debug("cache said ENODATA"); |
176 | goto go_on; | |
177 | ||
178 | /* page will not be cached */ | |
179 | case -ENOBUFS: | |
180 | _debug("cache said ENOBUFS"); | |
1da177e4 | 181 | default: |
9b3f26c9 | 182 | go_on: |
08e0e7c8 DH |
183 | offset = page->index << PAGE_CACHE_SHIFT; |
184 | len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE); | |
1da177e4 LT |
185 | |
186 | /* read the contents of the file from the server into the | |
187 | * page */ | |
00d3b7a4 | 188 | ret = afs_vnode_fetch_data(vnode, key, offset, len, page); |
1da177e4 | 189 | if (ret < 0) { |
08e0e7c8 | 190 | if (ret == -ENOENT) { |
1da177e4 LT |
191 | _debug("got NOENT from server" |
192 | " - marking file deleted and stale"); | |
08e0e7c8 | 193 | set_bit(AFS_VNODE_DELETED, &vnode->flags); |
1da177e4 LT |
194 | ret = -ESTALE; |
195 | } | |
9b3f26c9 DH |
196 | |
197 | #ifdef CONFIG_AFS_FSCACHE | |
198 | fscache_uncache_page(vnode->cache, page); | |
1da177e4 | 199 | #endif |
9b3f26c9 | 200 | BUG_ON(PageFsCache(page)); |
1da177e4 LT |
201 | goto error; |
202 | } | |
203 | ||
204 | SetPageUptodate(page); | |
205 | ||
9b3f26c9 DH |
206 | /* send the page to the cache */ |
207 | #ifdef CONFIG_AFS_FSCACHE | |
208 | if (PageFsCache(page) && | |
209 | fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) { | |
210 | fscache_uncache_page(vnode->cache, page); | |
211 | BUG_ON(PageFsCache(page)); | |
1da177e4 | 212 | } |
1da177e4 | 213 | #endif |
9b3f26c9 | 214 | unlock_page(page); |
1da177e4 LT |
215 | } |
216 | ||
9886e836 DH |
217 | if (!file) |
218 | key_put(key); | |
1da177e4 LT |
219 | _leave(" = 0"); |
220 | return 0; | |
221 | ||
08e0e7c8 | 222 | error: |
1da177e4 LT |
223 | SetPageError(page); |
224 | unlock_page(page); | |
9886e836 DH |
225 | if (!file) |
226 | key_put(key); | |
227 | error_nokey: | |
1da177e4 LT |
228 | _leave(" = %d", ret); |
229 | return ret; | |
ec26815a | 230 | } |
1da177e4 | 231 | |
1da177e4 | 232 | /* |
9b3f26c9 | 233 | * read a set of pages |
1da177e4 | 234 | */ |
9b3f26c9 DH |
235 | static int afs_readpages(struct file *file, struct address_space *mapping, |
236 | struct list_head *pages, unsigned nr_pages) | |
1da177e4 | 237 | { |
9b3f26c9 DH |
238 | struct afs_vnode *vnode; |
239 | int ret = 0; | |
1da177e4 | 240 | |
9b3f26c9 | 241 | _enter(",{%lu},,%d", mapping->host->i_ino, nr_pages); |
1da177e4 | 242 | |
9b3f26c9 DH |
243 | vnode = AFS_FS_I(mapping->host); |
244 | if (vnode->flags & AFS_VNODE_DELETED) { | |
245 | _leave(" = -ESTALE"); | |
246 | return -ESTALE; | |
247 | } | |
1da177e4 | 248 | |
9b3f26c9 DH |
249 | /* attempt to read as many of the pages as possible */ |
250 | #ifdef CONFIG_AFS_FSCACHE | |
251 | ret = fscache_read_or_alloc_pages(vnode->cache, | |
252 | mapping, | |
253 | pages, | |
254 | &nr_pages, | |
255 | afs_file_readpage_read_complete, | |
256 | NULL, | |
257 | mapping_gfp_mask(mapping)); | |
258 | #else | |
259 | ret = -ENOBUFS; | |
260 | #endif | |
261 | ||
262 | switch (ret) { | |
263 | /* all pages are being read from the cache */ | |
264 | case 0: | |
265 | BUG_ON(!list_empty(pages)); | |
266 | BUG_ON(nr_pages != 0); | |
267 | _leave(" = 0 [reading all]"); | |
268 | return 0; | |
269 | ||
270 | /* there were pages that couldn't be read from the cache */ | |
271 | case -ENODATA: | |
272 | case -ENOBUFS: | |
273 | break; | |
274 | ||
275 | /* other error */ | |
276 | default: | |
277 | _leave(" = %d", ret); | |
278 | return ret; | |
1da177e4 LT |
279 | } |
280 | ||
9b3f26c9 DH |
281 | /* load the missing pages from the network */ |
282 | ret = read_cache_pages(mapping, pages, (void *) afs_readpage, file); | |
283 | ||
284 | _leave(" = %d [netting]", ret); | |
285 | return ret; | |
ec26815a | 286 | } |
1da177e4 | 287 | |
31143d5d DH |
288 | /* |
289 | * write back a dirty page | |
290 | */ | |
291 | static int afs_launder_page(struct page *page) | |
292 | { | |
293 | _enter("{%lu}", page->index); | |
294 | ||
295 | return 0; | |
296 | } | |
297 | ||
1da177e4 | 298 | /* |
9b3f26c9 DH |
299 | * invalidate part or all of a page |
300 | * - release a page and clean up its private data if offset is 0 (indicating | |
301 | * the entire page) | |
302 | */ | |
303 | static void afs_invalidatepage(struct page *page, unsigned long offset) | |
304 | { | |
305 | struct afs_writeback *wb = (struct afs_writeback *) page_private(page); | |
306 | ||
307 | _enter("{%lu},%lu", page->index, offset); | |
308 | ||
309 | BUG_ON(!PageLocked(page)); | |
310 | ||
311 | /* we clean up only if the entire page is being invalidated */ | |
312 | if (offset == 0) { | |
313 | #ifdef CONFIG_AFS_FSCACHE | |
314 | if (PageFsCache(page)) { | |
315 | struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); | |
316 | fscache_wait_on_page_write(vnode->cache, page); | |
317 | fscache_uncache_page(vnode->cache, page); | |
318 | ClearPageFsCache(page); | |
319 | } | |
320 | #endif | |
321 | ||
322 | if (PagePrivate(page)) { | |
323 | if (wb && !PageWriteback(page)) { | |
324 | set_page_private(page, 0); | |
325 | afs_put_writeback(wb); | |
326 | } | |
327 | ||
328 | if (!page_private(page)) | |
329 | ClearPagePrivate(page); | |
330 | } | |
331 | } | |
332 | ||
333 | _leave(""); | |
334 | } | |
335 | ||
336 | /* | |
337 | * release a page and clean up its private state if it's not busy | |
338 | * - return true if the page can now be released, false if not | |
1da177e4 | 339 | */ |
416351f2 | 340 | static int afs_releasepage(struct page *page, gfp_t gfp_flags) |
1da177e4 | 341 | { |
9b3f26c9 | 342 | struct afs_writeback *wb = (struct afs_writeback *) page_private(page); |
416351f2 | 343 | struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); |
1da177e4 | 344 | |
416351f2 DH |
345 | _enter("{{%x:%u}[%lu],%lx},%x", |
346 | vnode->fid.vid, vnode->fid.vnode, page->index, page->flags, | |
347 | gfp_flags); | |
1da177e4 | 348 | |
9b3f26c9 DH |
349 | /* deny if page is being written to the cache and the caller hasn't |
350 | * elected to wait */ | |
351 | #ifdef CONFIG_AFS_FSCACHE | |
352 | if (PageFsCache(page)) { | |
353 | if (fscache_check_page_write(vnode->cache, page)) { | |
354 | if (!(gfp_flags & __GFP_WAIT)) { | |
355 | _leave(" = F [cache busy]"); | |
356 | return 0; | |
357 | } | |
358 | fscache_wait_on_page_write(vnode->cache, page); | |
359 | } | |
360 | ||
361 | fscache_uncache_page(vnode->cache, page); | |
362 | ClearPageFsCache(page); | |
363 | } | |
364 | #endif | |
365 | ||
1da177e4 | 366 | if (PagePrivate(page)) { |
9b3f26c9 DH |
367 | if (wb) { |
368 | set_page_private(page, 0); | |
369 | afs_put_writeback(wb); | |
370 | } | |
1da177e4 | 371 | ClearPagePrivate(page); |
1da177e4 LT |
372 | } |
373 | ||
9b3f26c9 DH |
374 | /* indicate that the page can be released */ |
375 | _leave(" = T"); | |
376 | return 1; | |
ec26815a | 377 | } |