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1/* AFS filesystem file handling
2 *
3 * Copyright (C) 2002, 2007 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/fs.h>
16#include <linux/pagemap.h>
17#include <linux/writeback.h>
18#include <linux/gfp.h>
19#include "internal.h"
20
21static int afs_readpage(struct file *file, struct page *page);
22static void afs_invalidatepage(struct page *page, unsigned int offset,
23 unsigned int length);
24static int afs_releasepage(struct page *page, gfp_t gfp_flags);
25static int afs_launder_page(struct page *page);
26
27static int afs_readpages(struct file *filp, struct address_space *mapping,
28 struct list_head *pages, unsigned nr_pages);
29
30const struct file_operations afs_file_operations = {
31 .open = afs_open,
32 .release = afs_release,
33 .llseek = generic_file_llseek,
34 .read = do_sync_read,
35 .write = do_sync_write,
36 .aio_read = generic_file_aio_read,
37 .aio_write = afs_file_write,
38 .mmap = generic_file_readonly_mmap,
39 .splice_read = generic_file_splice_read,
40 .fsync = afs_fsync,
41 .lock = afs_lock,
42 .flock = afs_flock,
43};
44
45const struct inode_operations afs_file_inode_operations = {
46 .getattr = afs_getattr,
47 .setattr = afs_setattr,
48 .permission = afs_permission,
49};
50
51const struct address_space_operations afs_fs_aops = {
52 .readpage = afs_readpage,
53 .readpages = afs_readpages,
54 .set_page_dirty = afs_set_page_dirty,
55 .launder_page = afs_launder_page,
56 .releasepage = afs_releasepage,
57 .invalidatepage = afs_invalidatepage,
58 .write_begin = afs_write_begin,
59 .write_end = afs_write_end,
60 .writepage = afs_writepage,
61 .writepages = afs_writepages,
62};
63
64/*
65 * open an AFS file or directory and attach a key to it
66 */
67int afs_open(struct inode *inode, struct file *file)
68{
69 struct afs_vnode *vnode = AFS_FS_I(inode);
70 struct key *key;
71 int ret;
72
73 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
74
75 key = afs_request_key(vnode->volume->cell);
76 if (IS_ERR(key)) {
77 _leave(" = %ld [key]", PTR_ERR(key));
78 return PTR_ERR(key);
79 }
80
81 ret = afs_validate(vnode, key);
82 if (ret < 0) {
83 _leave(" = %d [val]", ret);
84 return ret;
85 }
86
87 file->private_data = key;
88 _leave(" = 0");
89 return 0;
90}
91
92/*
93 * release an AFS file or directory and discard its key
94 */
95int afs_release(struct inode *inode, struct file *file)
96{
97 struct afs_vnode *vnode = AFS_FS_I(inode);
98
99 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
100
101 key_put(file->private_data);
102 _leave(" = 0");
103 return 0;
104}
105
106#ifdef CONFIG_AFS_FSCACHE
107/*
108 * deal with notification that a page was read from the cache
109 */
110static void afs_file_readpage_read_complete(struct page *page,
111 void *data,
112 int error)
113{
114 _enter("%p,%p,%d", page, data, error);
115
116 /* if the read completes with an error, we just unlock the page and let
117 * the VM reissue the readpage */
118 if (!error)
119 SetPageUptodate(page);
120 unlock_page(page);
121}
122#endif
123
124/*
125 * read page from file, directory or symlink, given a key to use
126 */
127int afs_page_filler(void *data, struct page *page)
128{
129 struct inode *inode = page->mapping->host;
130 struct afs_vnode *vnode = AFS_FS_I(inode);
131 struct key *key = data;
132 size_t len;
133 off_t offset;
134 int ret;
135
136 _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
137
138 BUG_ON(!PageLocked(page));
139
140 ret = -ESTALE;
141 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
142 goto error;
143
144 /* is it cached? */
145#ifdef CONFIG_AFS_FSCACHE
146 ret = fscache_read_or_alloc_page(vnode->cache,
147 page,
148 afs_file_readpage_read_complete,
149 NULL,
150 GFP_KERNEL);
151#else
152 ret = -ENOBUFS;
153#endif
154 switch (ret) {
155 /* read BIO submitted (page in cache) */
156 case 0:
157 break;
158
159 /* page not yet cached */
160 case -ENODATA:
161 _debug("cache said ENODATA");
162 goto go_on;
163
164 /* page will not be cached */
165 case -ENOBUFS:
166 _debug("cache said ENOBUFS");
167 default:
168 go_on:
169 offset = page->index << PAGE_CACHE_SHIFT;
170 len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);
171
172 /* read the contents of the file from the server into the
173 * page */
174 ret = afs_vnode_fetch_data(vnode, key, offset, len, page);
175 if (ret < 0) {
176 if (ret == -ENOENT) {
177 _debug("got NOENT from server"
178 " - marking file deleted and stale");
179 set_bit(AFS_VNODE_DELETED, &vnode->flags);
180 ret = -ESTALE;
181 }
182
183#ifdef CONFIG_AFS_FSCACHE
184 fscache_uncache_page(vnode->cache, page);
185#endif
186 BUG_ON(PageFsCache(page));
187 goto error;
188 }
189
190 SetPageUptodate(page);
191
192 /* send the page to the cache */
193#ifdef CONFIG_AFS_FSCACHE
194 if (PageFsCache(page) &&
195 fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) {
196 fscache_uncache_page(vnode->cache, page);
197 BUG_ON(PageFsCache(page));
198 }
199#endif
200 unlock_page(page);
201 }
202
203 _leave(" = 0");
204 return 0;
205
206error:
207 SetPageError(page);
208 unlock_page(page);
209 _leave(" = %d", ret);
210 return ret;
211}
212
213/*
214 * read page from file, directory or symlink, given a file to nominate the key
215 * to be used
216 */
217static int afs_readpage(struct file *file, struct page *page)
218{
219 struct key *key;
220 int ret;
221
222 if (file) {
223 key = file->private_data;
224 ASSERT(key != NULL);
225 ret = afs_page_filler(key, page);
226 } else {
227 struct inode *inode = page->mapping->host;
228 key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
229 if (IS_ERR(key)) {
230 ret = PTR_ERR(key);
231 } else {
232 ret = afs_page_filler(key, page);
233 key_put(key);
234 }
235 }
236 return ret;
237}
238
239/*
240 * read a set of pages
241 */
242static int afs_readpages(struct file *file, struct address_space *mapping,
243 struct list_head *pages, unsigned nr_pages)
244{
245 struct key *key = file->private_data;
246 struct afs_vnode *vnode;
247 int ret = 0;
248
249 _enter("{%d},{%lu},,%d",
250 key_serial(key), mapping->host->i_ino, nr_pages);
251
252 ASSERT(key != NULL);
253
254 vnode = AFS_FS_I(mapping->host);
255 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
256 _leave(" = -ESTALE");
257 return -ESTALE;
258 }
259
260 /* attempt to read as many of the pages as possible */
261#ifdef CONFIG_AFS_FSCACHE
262 ret = fscache_read_or_alloc_pages(vnode->cache,
263 mapping,
264 pages,
265 &nr_pages,
266 afs_file_readpage_read_complete,
267 NULL,
268 mapping_gfp_mask(mapping));
269#else
270 ret = -ENOBUFS;
271#endif
272
273 switch (ret) {
274 /* all pages are being read from the cache */
275 case 0:
276 BUG_ON(!list_empty(pages));
277 BUG_ON(nr_pages != 0);
278 _leave(" = 0 [reading all]");
279 return 0;
280
281 /* there were pages that couldn't be read from the cache */
282 case -ENODATA:
283 case -ENOBUFS:
284 break;
285
286 /* other error */
287 default:
288 _leave(" = %d", ret);
289 return ret;
290 }
291
292 /* load the missing pages from the network */
293 ret = read_cache_pages(mapping, pages, afs_page_filler, key);
294
295 _leave(" = %d [netting]", ret);
296 return ret;
297}
298
299/*
300 * write back a dirty page
301 */
302static int afs_launder_page(struct page *page)
303{
304 _enter("{%lu}", page->index);
305
306 return 0;
307}
308
309/*
310 * invalidate part or all of a page
311 * - release a page and clean up its private data if offset is 0 (indicating
312 * the entire page)
313 */
314static void afs_invalidatepage(struct page *page, unsigned int offset,
315 unsigned int length)
316{
317 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
318
319 _enter("{%lu},%u,%u", page->index, offset, length);
320
321 BUG_ON(!PageLocked(page));
322
323 /* we clean up only if the entire page is being invalidated */
324 if (offset == 0 && length == PAGE_CACHE_SIZE) {
325#ifdef CONFIG_AFS_FSCACHE
326 if (PageFsCache(page)) {
327 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
328 fscache_wait_on_page_write(vnode->cache, page);
329 fscache_uncache_page(vnode->cache, page);
330 }
331#endif
332
333 if (PagePrivate(page)) {
334 if (wb && !PageWriteback(page)) {
335 set_page_private(page, 0);
336 afs_put_writeback(wb);
337 }
338
339 if (!page_private(page))
340 ClearPagePrivate(page);
341 }
342 }
343
344 _leave("");
345}
346
347/*
348 * release a page and clean up its private state if it's not busy
349 * - return true if the page can now be released, false if not
350 */
351static int afs_releasepage(struct page *page, gfp_t gfp_flags)
352{
353 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
354 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
355
356 _enter("{{%x:%u}[%lu],%lx},%x",
357 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
358 gfp_flags);
359
360 /* deny if page is being written to the cache and the caller hasn't
361 * elected to wait */
362#ifdef CONFIG_AFS_FSCACHE
363 if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
364 _leave(" = F [cache busy]");
365 return 0;
366 }
367#endif
368
369 if (PagePrivate(page)) {
370 if (wb) {
371 set_page_private(page, 0);
372 afs_put_writeback(wb);
373 }
374 ClearPagePrivate(page);
375 }
376
377 /* indicate that the page can be released */
378 _leave(" = T");
379 return 1;
380}
1/* AFS filesystem file handling
2 *
3 * Copyright (C) 2002, 2007 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/fs.h>
16#include <linux/pagemap.h>
17#include <linux/writeback.h>
18#include <linux/gfp.h>
19#include "internal.h"
20
21static int afs_readpage(struct file *file, struct page *page);
22static void afs_invalidatepage(struct page *page, unsigned int offset,
23 unsigned int length);
24static int afs_releasepage(struct page *page, gfp_t gfp_flags);
25static int afs_launder_page(struct page *page);
26
27static int afs_readpages(struct file *filp, struct address_space *mapping,
28 struct list_head *pages, unsigned nr_pages);
29
30const struct file_operations afs_file_operations = {
31 .open = afs_open,
32 .release = afs_release,
33 .llseek = generic_file_llseek,
34 .read_iter = generic_file_read_iter,
35 .write_iter = afs_file_write,
36 .mmap = generic_file_readonly_mmap,
37 .splice_read = generic_file_splice_read,
38 .fsync = afs_fsync,
39 .lock = afs_lock,
40 .flock = afs_flock,
41};
42
43const struct inode_operations afs_file_inode_operations = {
44 .getattr = afs_getattr,
45 .setattr = afs_setattr,
46 .permission = afs_permission,
47};
48
49const struct address_space_operations afs_fs_aops = {
50 .readpage = afs_readpage,
51 .readpages = afs_readpages,
52 .set_page_dirty = afs_set_page_dirty,
53 .launder_page = afs_launder_page,
54 .releasepage = afs_releasepage,
55 .invalidatepage = afs_invalidatepage,
56 .write_begin = afs_write_begin,
57 .write_end = afs_write_end,
58 .writepage = afs_writepage,
59 .writepages = afs_writepages,
60};
61
62/*
63 * open an AFS file or directory and attach a key to it
64 */
65int afs_open(struct inode *inode, struct file *file)
66{
67 struct afs_vnode *vnode = AFS_FS_I(inode);
68 struct key *key;
69 int ret;
70
71 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
72
73 key = afs_request_key(vnode->volume->cell);
74 if (IS_ERR(key)) {
75 _leave(" = %ld [key]", PTR_ERR(key));
76 return PTR_ERR(key);
77 }
78
79 ret = afs_validate(vnode, key);
80 if (ret < 0) {
81 _leave(" = %d [val]", ret);
82 return ret;
83 }
84
85 file->private_data = key;
86 _leave(" = 0");
87 return 0;
88}
89
90/*
91 * release an AFS file or directory and discard its key
92 */
93int afs_release(struct inode *inode, struct file *file)
94{
95 struct afs_vnode *vnode = AFS_FS_I(inode);
96
97 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
98
99 key_put(file->private_data);
100 _leave(" = 0");
101 return 0;
102}
103
104#ifdef CONFIG_AFS_FSCACHE
105/*
106 * deal with notification that a page was read from the cache
107 */
108static void afs_file_readpage_read_complete(struct page *page,
109 void *data,
110 int error)
111{
112 _enter("%p,%p,%d", page, data, error);
113
114 /* if the read completes with an error, we just unlock the page and let
115 * the VM reissue the readpage */
116 if (!error)
117 SetPageUptodate(page);
118 unlock_page(page);
119}
120#endif
121
122/*
123 * read page from file, directory or symlink, given a key to use
124 */
125int afs_page_filler(void *data, struct page *page)
126{
127 struct inode *inode = page->mapping->host;
128 struct afs_vnode *vnode = AFS_FS_I(inode);
129 struct key *key = data;
130 size_t len;
131 off_t offset;
132 int ret;
133
134 _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
135
136 BUG_ON(!PageLocked(page));
137
138 ret = -ESTALE;
139 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
140 goto error;
141
142 /* is it cached? */
143#ifdef CONFIG_AFS_FSCACHE
144 ret = fscache_read_or_alloc_page(vnode->cache,
145 page,
146 afs_file_readpage_read_complete,
147 NULL,
148 GFP_KERNEL);
149#else
150 ret = -ENOBUFS;
151#endif
152 switch (ret) {
153 /* read BIO submitted (page in cache) */
154 case 0:
155 break;
156
157 /* page not yet cached */
158 case -ENODATA:
159 _debug("cache said ENODATA");
160 goto go_on;
161
162 /* page will not be cached */
163 case -ENOBUFS:
164 _debug("cache said ENOBUFS");
165 default:
166 go_on:
167 offset = page->index << PAGE_SHIFT;
168 len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);
169
170 /* read the contents of the file from the server into the
171 * page */
172 ret = afs_vnode_fetch_data(vnode, key, offset, len, page);
173 if (ret < 0) {
174 if (ret == -ENOENT) {
175 _debug("got NOENT from server"
176 " - marking file deleted and stale");
177 set_bit(AFS_VNODE_DELETED, &vnode->flags);
178 ret = -ESTALE;
179 }
180
181#ifdef CONFIG_AFS_FSCACHE
182 fscache_uncache_page(vnode->cache, page);
183#endif
184 BUG_ON(PageFsCache(page));
185 goto error;
186 }
187
188 SetPageUptodate(page);
189
190 /* send the page to the cache */
191#ifdef CONFIG_AFS_FSCACHE
192 if (PageFsCache(page) &&
193 fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) {
194 fscache_uncache_page(vnode->cache, page);
195 BUG_ON(PageFsCache(page));
196 }
197#endif
198 unlock_page(page);
199 }
200
201 _leave(" = 0");
202 return 0;
203
204error:
205 SetPageError(page);
206 unlock_page(page);
207 _leave(" = %d", ret);
208 return ret;
209}
210
211/*
212 * read page from file, directory or symlink, given a file to nominate the key
213 * to be used
214 */
215static int afs_readpage(struct file *file, struct page *page)
216{
217 struct key *key;
218 int ret;
219
220 if (file) {
221 key = file->private_data;
222 ASSERT(key != NULL);
223 ret = afs_page_filler(key, page);
224 } else {
225 struct inode *inode = page->mapping->host;
226 key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
227 if (IS_ERR(key)) {
228 ret = PTR_ERR(key);
229 } else {
230 ret = afs_page_filler(key, page);
231 key_put(key);
232 }
233 }
234 return ret;
235}
236
237/*
238 * read a set of pages
239 */
240static int afs_readpages(struct file *file, struct address_space *mapping,
241 struct list_head *pages, unsigned nr_pages)
242{
243 struct key *key = file->private_data;
244 struct afs_vnode *vnode;
245 int ret = 0;
246
247 _enter("{%d},{%lu},,%d",
248 key_serial(key), mapping->host->i_ino, nr_pages);
249
250 ASSERT(key != NULL);
251
252 vnode = AFS_FS_I(mapping->host);
253 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
254 _leave(" = -ESTALE");
255 return -ESTALE;
256 }
257
258 /* attempt to read as many of the pages as possible */
259#ifdef CONFIG_AFS_FSCACHE
260 ret = fscache_read_or_alloc_pages(vnode->cache,
261 mapping,
262 pages,
263 &nr_pages,
264 afs_file_readpage_read_complete,
265 NULL,
266 mapping_gfp_mask(mapping));
267#else
268 ret = -ENOBUFS;
269#endif
270
271 switch (ret) {
272 /* all pages are being read from the cache */
273 case 0:
274 BUG_ON(!list_empty(pages));
275 BUG_ON(nr_pages != 0);
276 _leave(" = 0 [reading all]");
277 return 0;
278
279 /* there were pages that couldn't be read from the cache */
280 case -ENODATA:
281 case -ENOBUFS:
282 break;
283
284 /* other error */
285 default:
286 _leave(" = %d", ret);
287 return ret;
288 }
289
290 /* load the missing pages from the network */
291 ret = read_cache_pages(mapping, pages, afs_page_filler, key);
292
293 _leave(" = %d [netting]", ret);
294 return ret;
295}
296
297/*
298 * write back a dirty page
299 */
300static int afs_launder_page(struct page *page)
301{
302 _enter("{%lu}", page->index);
303
304 return 0;
305}
306
307/*
308 * invalidate part or all of a page
309 * - release a page and clean up its private data if offset is 0 (indicating
310 * the entire page)
311 */
312static void afs_invalidatepage(struct page *page, unsigned int offset,
313 unsigned int length)
314{
315 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
316
317 _enter("{%lu},%u,%u", page->index, offset, length);
318
319 BUG_ON(!PageLocked(page));
320
321 /* we clean up only if the entire page is being invalidated */
322 if (offset == 0 && length == PAGE_SIZE) {
323#ifdef CONFIG_AFS_FSCACHE
324 if (PageFsCache(page)) {
325 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
326 fscache_wait_on_page_write(vnode->cache, page);
327 fscache_uncache_page(vnode->cache, page);
328 }
329#endif
330
331 if (PagePrivate(page)) {
332 if (wb && !PageWriteback(page)) {
333 set_page_private(page, 0);
334 afs_put_writeback(wb);
335 }
336
337 if (!page_private(page))
338 ClearPagePrivate(page);
339 }
340 }
341
342 _leave("");
343}
344
345/*
346 * release a page and clean up its private state if it's not busy
347 * - return true if the page can now be released, false if not
348 */
349static int afs_releasepage(struct page *page, gfp_t gfp_flags)
350{
351 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
352 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
353
354 _enter("{{%x:%u}[%lu],%lx},%x",
355 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
356 gfp_flags);
357
358 /* deny if page is being written to the cache and the caller hasn't
359 * elected to wait */
360#ifdef CONFIG_AFS_FSCACHE
361 if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
362 _leave(" = F [cache busy]");
363 return 0;
364 }
365#endif
366
367 if (PagePrivate(page)) {
368 if (wb) {
369 set_page_private(page, 0);
370 afs_put_writeback(wb);
371 }
372 ClearPagePrivate(page);
373 }
374
375 /* indicate that the page can be released */
376 _leave(" = T");
377 return 1;
378}