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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 | ||
00d3b7a4 DH |
137 | ASSERT(file != NULL); |
138 | key = file->private_data; | |
139 | ASSERT(key != NULL); | |
140 | ||
141 | _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index); | |
1da177e4 LT |
142 | |
143 | vnode = AFS_FS_I(inode); | |
144 | ||
cd7619d6 | 145 | BUG_ON(!PageLocked(page)); |
1da177e4 LT |
146 | |
147 | ret = -ESTALE; | |
08e0e7c8 | 148 | if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) |
1da177e4 LT |
149 | goto error; |
150 | ||
1da177e4 | 151 | /* is it cached? */ |
9b3f26c9 DH |
152 | #ifdef CONFIG_AFS_FSCACHE |
153 | ret = fscache_read_or_alloc_page(vnode->cache, | |
1da177e4 LT |
154 | page, |
155 | afs_file_readpage_read_complete, | |
156 | NULL, | |
157 | GFP_KERNEL); | |
158 | #else | |
159 | ret = -ENOBUFS; | |
160 | #endif | |
1da177e4 | 161 | switch (ret) { |
1da177e4 LT |
162 | /* read BIO submitted (page in cache) */ |
163 | case 0: | |
164 | break; | |
165 | ||
9b3f26c9 | 166 | /* page not yet cached */ |
1da177e4 | 167 | case -ENODATA: |
9b3f26c9 DH |
168 | _debug("cache said ENODATA"); |
169 | goto go_on; | |
170 | ||
171 | /* page will not be cached */ | |
172 | case -ENOBUFS: | |
173 | _debug("cache said ENOBUFS"); | |
1da177e4 | 174 | default: |
9b3f26c9 | 175 | go_on: |
08e0e7c8 DH |
176 | offset = page->index << PAGE_CACHE_SHIFT; |
177 | len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE); | |
1da177e4 LT |
178 | |
179 | /* read the contents of the file from the server into the | |
180 | * page */ | |
00d3b7a4 | 181 | ret = afs_vnode_fetch_data(vnode, key, offset, len, page); |
1da177e4 | 182 | if (ret < 0) { |
08e0e7c8 | 183 | if (ret == -ENOENT) { |
1da177e4 LT |
184 | _debug("got NOENT from server" |
185 | " - marking file deleted and stale"); | |
08e0e7c8 | 186 | set_bit(AFS_VNODE_DELETED, &vnode->flags); |
1da177e4 LT |
187 | ret = -ESTALE; |
188 | } | |
9b3f26c9 DH |
189 | |
190 | #ifdef CONFIG_AFS_FSCACHE | |
191 | fscache_uncache_page(vnode->cache, page); | |
1da177e4 | 192 | #endif |
9b3f26c9 | 193 | BUG_ON(PageFsCache(page)); |
1da177e4 LT |
194 | goto error; |
195 | } | |
196 | ||
197 | SetPageUptodate(page); | |
198 | ||
9b3f26c9 DH |
199 | /* send the page to the cache */ |
200 | #ifdef CONFIG_AFS_FSCACHE | |
201 | if (PageFsCache(page) && | |
202 | fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) { | |
203 | fscache_uncache_page(vnode->cache, page); | |
204 | BUG_ON(PageFsCache(page)); | |
1da177e4 | 205 | } |
1da177e4 | 206 | #endif |
9b3f26c9 | 207 | unlock_page(page); |
1da177e4 LT |
208 | } |
209 | ||
210 | _leave(" = 0"); | |
211 | return 0; | |
212 | ||
08e0e7c8 | 213 | error: |
1da177e4 LT |
214 | SetPageError(page); |
215 | unlock_page(page); | |
1da177e4 LT |
216 | _leave(" = %d", ret); |
217 | return ret; | |
ec26815a | 218 | } |
1da177e4 | 219 | |
1da177e4 | 220 | /* |
9b3f26c9 | 221 | * read a set of pages |
1da177e4 | 222 | */ |
9b3f26c9 DH |
223 | static int afs_readpages(struct file *file, struct address_space *mapping, |
224 | struct list_head *pages, unsigned nr_pages) | |
1da177e4 | 225 | { |
9b3f26c9 DH |
226 | struct afs_vnode *vnode; |
227 | int ret = 0; | |
1da177e4 | 228 | |
9b3f26c9 | 229 | _enter(",{%lu},,%d", mapping->host->i_ino, nr_pages); |
1da177e4 | 230 | |
9b3f26c9 DH |
231 | vnode = AFS_FS_I(mapping->host); |
232 | if (vnode->flags & AFS_VNODE_DELETED) { | |
233 | _leave(" = -ESTALE"); | |
234 | return -ESTALE; | |
235 | } | |
1da177e4 | 236 | |
9b3f26c9 DH |
237 | /* attempt to read as many of the pages as possible */ |
238 | #ifdef CONFIG_AFS_FSCACHE | |
239 | ret = fscache_read_or_alloc_pages(vnode->cache, | |
240 | mapping, | |
241 | pages, | |
242 | &nr_pages, | |
243 | afs_file_readpage_read_complete, | |
244 | NULL, | |
245 | mapping_gfp_mask(mapping)); | |
246 | #else | |
247 | ret = -ENOBUFS; | |
248 | #endif | |
249 | ||
250 | switch (ret) { | |
251 | /* all pages are being read from the cache */ | |
252 | case 0: | |
253 | BUG_ON(!list_empty(pages)); | |
254 | BUG_ON(nr_pages != 0); | |
255 | _leave(" = 0 [reading all]"); | |
256 | return 0; | |
257 | ||
258 | /* there were pages that couldn't be read from the cache */ | |
259 | case -ENODATA: | |
260 | case -ENOBUFS: | |
261 | break; | |
262 | ||
263 | /* other error */ | |
264 | default: | |
265 | _leave(" = %d", ret); | |
266 | return ret; | |
1da177e4 LT |
267 | } |
268 | ||
9b3f26c9 DH |
269 | /* load the missing pages from the network */ |
270 | ret = read_cache_pages(mapping, pages, (void *) afs_readpage, file); | |
271 | ||
272 | _leave(" = %d [netting]", ret); | |
273 | return ret; | |
ec26815a | 274 | } |
1da177e4 | 275 | |
31143d5d DH |
276 | /* |
277 | * write back a dirty page | |
278 | */ | |
279 | static int afs_launder_page(struct page *page) | |
280 | { | |
281 | _enter("{%lu}", page->index); | |
282 | ||
283 | return 0; | |
284 | } | |
285 | ||
1da177e4 | 286 | /* |
9b3f26c9 DH |
287 | * invalidate part or all of a page |
288 | * - release a page and clean up its private data if offset is 0 (indicating | |
289 | * the entire page) | |
290 | */ | |
291 | static void afs_invalidatepage(struct page *page, unsigned long offset) | |
292 | { | |
293 | struct afs_writeback *wb = (struct afs_writeback *) page_private(page); | |
294 | ||
295 | _enter("{%lu},%lu", page->index, offset); | |
296 | ||
297 | BUG_ON(!PageLocked(page)); | |
298 | ||
299 | /* we clean up only if the entire page is being invalidated */ | |
300 | if (offset == 0) { | |
301 | #ifdef CONFIG_AFS_FSCACHE | |
302 | if (PageFsCache(page)) { | |
303 | struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); | |
304 | fscache_wait_on_page_write(vnode->cache, page); | |
305 | fscache_uncache_page(vnode->cache, page); | |
306 | ClearPageFsCache(page); | |
307 | } | |
308 | #endif | |
309 | ||
310 | if (PagePrivate(page)) { | |
311 | if (wb && !PageWriteback(page)) { | |
312 | set_page_private(page, 0); | |
313 | afs_put_writeback(wb); | |
314 | } | |
315 | ||
316 | if (!page_private(page)) | |
317 | ClearPagePrivate(page); | |
318 | } | |
319 | } | |
320 | ||
321 | _leave(""); | |
322 | } | |
323 | ||
324 | /* | |
325 | * release a page and clean up its private state if it's not busy | |
326 | * - return true if the page can now be released, false if not | |
1da177e4 | 327 | */ |
416351f2 | 328 | static int afs_releasepage(struct page *page, gfp_t gfp_flags) |
1da177e4 | 329 | { |
9b3f26c9 | 330 | struct afs_writeback *wb = (struct afs_writeback *) page_private(page); |
416351f2 | 331 | struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); |
1da177e4 | 332 | |
416351f2 DH |
333 | _enter("{{%x:%u}[%lu],%lx},%x", |
334 | vnode->fid.vid, vnode->fid.vnode, page->index, page->flags, | |
335 | gfp_flags); | |
1da177e4 | 336 | |
9b3f26c9 DH |
337 | /* deny if page is being written to the cache and the caller hasn't |
338 | * elected to wait */ | |
339 | #ifdef CONFIG_AFS_FSCACHE | |
340 | if (PageFsCache(page)) { | |
341 | if (fscache_check_page_write(vnode->cache, page)) { | |
342 | if (!(gfp_flags & __GFP_WAIT)) { | |
343 | _leave(" = F [cache busy]"); | |
344 | return 0; | |
345 | } | |
346 | fscache_wait_on_page_write(vnode->cache, page); | |
347 | } | |
348 | ||
349 | fscache_uncache_page(vnode->cache, page); | |
350 | ClearPageFsCache(page); | |
351 | } | |
352 | #endif | |
353 | ||
1da177e4 | 354 | if (PagePrivate(page)) { |
9b3f26c9 DH |
355 | if (wb) { |
356 | set_page_private(page, 0); | |
357 | afs_put_writeback(wb); | |
358 | } | |
1da177e4 | 359 | ClearPagePrivate(page); |
1da177e4 LT |
360 | } |
361 | ||
9b3f26c9 DH |
362 | /* indicate that the page can be released */ |
363 | _leave(" = T"); | |
364 | return 1; | |
ec26815a | 365 | } |