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1da177e4 LT |
1 | /* file.c: AFS filesystem file handling |
2 | * | |
3 | * Copyright (C) 2002 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/sched.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/pagemap.h> | |
19 | #include <linux/buffer_head.h> | |
20 | #include "volume.h" | |
21 | #include "vnode.h" | |
22 | #include <rxrpc/call.h> | |
23 | #include "internal.h" | |
24 | ||
25 | #if 0 | |
26 | static int afs_file_open(struct inode *inode, struct file *file); | |
27 | static int afs_file_release(struct inode *inode, struct file *file); | |
28 | #endif | |
29 | ||
30 | static int afs_file_readpage(struct file *file, struct page *page); | |
31 | static int afs_file_invalidatepage(struct page *page, unsigned long offset); | |
32 | static int afs_file_releasepage(struct page *page, int gfp_flags); | |
33 | ||
34 | static ssize_t afs_file_write(struct file *file, const char __user *buf, | |
35 | size_t size, loff_t *off); | |
36 | ||
37 | struct inode_operations afs_file_inode_operations = { | |
38 | .getattr = afs_inode_getattr, | |
39 | }; | |
40 | ||
41 | struct file_operations afs_file_file_operations = { | |
42 | .read = generic_file_read, | |
43 | .write = afs_file_write, | |
44 | .mmap = generic_file_mmap, | |
45 | #if 0 | |
46 | .open = afs_file_open, | |
47 | .release = afs_file_release, | |
48 | .fsync = afs_file_fsync, | |
49 | #endif | |
50 | }; | |
51 | ||
52 | struct address_space_operations afs_fs_aops = { | |
53 | .readpage = afs_file_readpage, | |
54 | .sync_page = block_sync_page, | |
55 | .set_page_dirty = __set_page_dirty_nobuffers, | |
56 | .releasepage = afs_file_releasepage, | |
57 | .invalidatepage = afs_file_invalidatepage, | |
58 | }; | |
59 | ||
60 | /*****************************************************************************/ | |
61 | /* | |
62 | * AFS file write | |
63 | */ | |
64 | static ssize_t afs_file_write(struct file *file, const char __user *buf, | |
65 | size_t size, loff_t *off) | |
66 | { | |
67 | struct afs_vnode *vnode; | |
68 | ||
69 | vnode = AFS_FS_I(file->f_dentry->d_inode); | |
70 | if (vnode->flags & AFS_VNODE_DELETED) | |
71 | return -ESTALE; | |
72 | ||
73 | return -EIO; | |
74 | } /* end afs_file_write() */ | |
75 | ||
76 | /*****************************************************************************/ | |
77 | /* | |
78 | * deal with notification that a page was read from the cache | |
79 | */ | |
80 | #ifdef AFS_CACHING_SUPPORT | |
81 | static void afs_file_readpage_read_complete(void *cookie_data, | |
82 | struct page *page, | |
83 | void *data, | |
84 | int error) | |
85 | { | |
86 | _enter("%p,%p,%p,%d", cookie_data, page, data, error); | |
87 | ||
88 | if (error) | |
89 | SetPageError(page); | |
90 | else | |
91 | SetPageUptodate(page); | |
92 | unlock_page(page); | |
93 | ||
94 | } /* end afs_file_readpage_read_complete() */ | |
95 | #endif | |
96 | ||
97 | /*****************************************************************************/ | |
98 | /* | |
99 | * deal with notification that a page was written to the cache | |
100 | */ | |
101 | #ifdef AFS_CACHING_SUPPORT | |
102 | static void afs_file_readpage_write_complete(void *cookie_data, | |
103 | struct page *page, | |
104 | void *data, | |
105 | int error) | |
106 | { | |
107 | _enter("%p,%p,%p,%d", cookie_data, page, data, error); | |
108 | ||
109 | unlock_page(page); | |
110 | ||
111 | } /* end afs_file_readpage_write_complete() */ | |
112 | #endif | |
113 | ||
114 | /*****************************************************************************/ | |
115 | /* | |
116 | * AFS read page from file (or symlink) | |
117 | */ | |
118 | static int afs_file_readpage(struct file *file, struct page *page) | |
119 | { | |
120 | struct afs_rxfs_fetch_descriptor desc; | |
121 | #ifdef AFS_CACHING_SUPPORT | |
122 | struct cachefs_page *pageio; | |
123 | #endif | |
124 | struct afs_vnode *vnode; | |
125 | struct inode *inode; | |
126 | int ret; | |
127 | ||
128 | inode = page->mapping->host; | |
129 | ||
130 | _enter("{%lu},{%lu}", inode->i_ino, page->index); | |
131 | ||
132 | vnode = AFS_FS_I(inode); | |
133 | ||
134 | if (!PageLocked(page)) | |
135 | PAGE_BUG(page); | |
136 | ||
137 | ret = -ESTALE; | |
138 | if (vnode->flags & AFS_VNODE_DELETED) | |
139 | goto error; | |
140 | ||
141 | #ifdef AFS_CACHING_SUPPORT | |
142 | ret = cachefs_page_get_private(page, &pageio, GFP_NOIO); | |
143 | if (ret < 0) | |
144 | goto error; | |
145 | ||
146 | /* is it cached? */ | |
147 | ret = cachefs_read_or_alloc_page(vnode->cache, | |
148 | page, | |
149 | afs_file_readpage_read_complete, | |
150 | NULL, | |
151 | GFP_KERNEL); | |
152 | #else | |
153 | ret = -ENOBUFS; | |
154 | #endif | |
155 | ||
156 | switch (ret) { | |
157 | /* read BIO submitted and wb-journal entry found */ | |
158 | case 1: | |
159 | BUG(); // TODO - handle wb-journal match | |
160 | ||
161 | /* read BIO submitted (page in cache) */ | |
162 | case 0: | |
163 | break; | |
164 | ||
165 | /* no page available in cache */ | |
166 | case -ENOBUFS: | |
167 | case -ENODATA: | |
168 | default: | |
169 | desc.fid = vnode->fid; | |
170 | desc.offset = page->index << PAGE_CACHE_SHIFT; | |
171 | desc.size = min((size_t) (inode->i_size - desc.offset), | |
172 | (size_t) PAGE_SIZE); | |
173 | desc.buffer = kmap(page); | |
174 | ||
175 | clear_page(desc.buffer); | |
176 | ||
177 | /* read the contents of the file from the server into the | |
178 | * page */ | |
179 | ret = afs_vnode_fetch_data(vnode, &desc); | |
180 | kunmap(page); | |
181 | if (ret < 0) { | |
182 | if (ret==-ENOENT) { | |
183 | _debug("got NOENT from server" | |
184 | " - marking file deleted and stale"); | |
185 | vnode->flags |= AFS_VNODE_DELETED; | |
186 | ret = -ESTALE; | |
187 | } | |
188 | ||
189 | #ifdef AFS_CACHING_SUPPORT | |
190 | cachefs_uncache_page(vnode->cache, page); | |
191 | #endif | |
192 | goto error; | |
193 | } | |
194 | ||
195 | SetPageUptodate(page); | |
196 | ||
197 | #ifdef AFS_CACHING_SUPPORT | |
198 | if (cachefs_write_page(vnode->cache, | |
199 | page, | |
200 | afs_file_readpage_write_complete, | |
201 | NULL, | |
202 | GFP_KERNEL) != 0 | |
203 | ) { | |
204 | cachefs_uncache_page(vnode->cache, page); | |
205 | unlock_page(page); | |
206 | } | |
207 | #else | |
208 | unlock_page(page); | |
209 | #endif | |
210 | } | |
211 | ||
212 | _leave(" = 0"); | |
213 | return 0; | |
214 | ||
215 | error: | |
216 | SetPageError(page); | |
217 | unlock_page(page); | |
218 | ||
219 | _leave(" = %d", ret); | |
220 | return ret; | |
221 | ||
222 | } /* end afs_file_readpage() */ | |
223 | ||
224 | /*****************************************************************************/ | |
225 | /* | |
226 | * get a page cookie for the specified page | |
227 | */ | |
228 | #ifdef AFS_CACHING_SUPPORT | |
229 | int afs_cache_get_page_cookie(struct page *page, | |
230 | struct cachefs_page **_page_cookie) | |
231 | { | |
232 | int ret; | |
233 | ||
234 | _enter(""); | |
235 | ret = cachefs_page_get_private(page,_page_cookie, GFP_NOIO); | |
236 | ||
237 | _leave(" = %d", ret); | |
238 | return ret; | |
239 | } /* end afs_cache_get_page_cookie() */ | |
240 | #endif | |
241 | ||
242 | /*****************************************************************************/ | |
243 | /* | |
244 | * invalidate part or all of a page | |
245 | */ | |
246 | static int afs_file_invalidatepage(struct page *page, unsigned long offset) | |
247 | { | |
248 | int ret = 1; | |
249 | ||
250 | _enter("{%lu},%lu", page->index, offset); | |
251 | ||
252 | BUG_ON(!PageLocked(page)); | |
253 | ||
254 | if (PagePrivate(page)) { | |
255 | #ifdef AFS_CACHING_SUPPORT | |
256 | struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); | |
257 | cachefs_uncache_page(vnode->cache,page); | |
258 | #endif | |
259 | ||
260 | /* We release buffers only if the entire page is being | |
261 | * invalidated. | |
262 | * The get_block cached value has been unconditionally | |
263 | * invalidated, so real IO is not possible anymore. | |
264 | */ | |
265 | if (offset == 0) { | |
266 | BUG_ON(!PageLocked(page)); | |
267 | ||
268 | ret = 0; | |
269 | if (!PageWriteback(page)) | |
270 | ret = page->mapping->a_ops->releasepage(page, | |
271 | 0); | |
272 | } | |
273 | } | |
274 | ||
275 | _leave(" = %d", ret); | |
276 | return ret; | |
277 | } /* end afs_file_invalidatepage() */ | |
278 | ||
279 | /*****************************************************************************/ | |
280 | /* | |
281 | * release a page and cleanup its private data | |
282 | */ | |
283 | static int afs_file_releasepage(struct page *page, int gfp_flags) | |
284 | { | |
285 | struct cachefs_page *pageio; | |
286 | ||
287 | _enter("{%lu},%x", page->index, gfp_flags); | |
288 | ||
289 | if (PagePrivate(page)) { | |
290 | #ifdef AFS_CACHING_SUPPORT | |
291 | struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); | |
292 | cachefs_uncache_page(vnode->cache, page); | |
293 | #endif | |
294 | ||
295 | pageio = (struct cachefs_page *) page->private; | |
296 | page->private = 0; | |
297 | ClearPagePrivate(page); | |
298 | ||
299 | if (pageio) | |
300 | kfree(pageio); | |
301 | } | |
302 | ||
303 | _leave(" = 0"); | |
304 | return 0; | |
305 | } /* end afs_file_releasepage() */ |