Loading...
1/*
2 * V9FS cache definitions.
3 *
4 * Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2
8 * as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to:
17 * Free Software Foundation
18 * 51 Franklin Street, Fifth Floor
19 * Boston, MA 02111-1301 USA
20 *
21 */
22
23#include <linux/jiffies.h>
24#include <linux/file.h>
25#include <linux/slab.h>
26#include <linux/stat.h>
27#include <linux/sched.h>
28#include <linux/fs.h>
29#include <net/9p/9p.h>
30
31#include "v9fs.h"
32#include "cache.h"
33
34#define CACHETAG_LEN 11
35
36struct fscache_netfs v9fs_cache_netfs = {
37 .name = "9p",
38 .version = 0,
39};
40
41/**
42 * v9fs_random_cachetag - Generate a random tag to be associated
43 * with a new cache session.
44 *
45 * The value of jiffies is used for a fairly randomly cache tag.
46 */
47
48static
49int v9fs_random_cachetag(struct v9fs_session_info *v9ses)
50{
51 v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL);
52 if (!v9ses->cachetag)
53 return -ENOMEM;
54
55 return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies);
56}
57
58static uint16_t v9fs_cache_session_get_key(const void *cookie_netfs_data,
59 void *buffer, uint16_t bufmax)
60{
61 struct v9fs_session_info *v9ses;
62 uint16_t klen = 0;
63
64 v9ses = (struct v9fs_session_info *)cookie_netfs_data;
65 p9_debug(P9_DEBUG_FSC, "session %p buf %p size %u\n",
66 v9ses, buffer, bufmax);
67
68 if (v9ses->cachetag)
69 klen = strlen(v9ses->cachetag);
70
71 if (klen > bufmax)
72 return 0;
73
74 memcpy(buffer, v9ses->cachetag, klen);
75 p9_debug(P9_DEBUG_FSC, "cache session tag %s\n", v9ses->cachetag);
76 return klen;
77}
78
79const struct fscache_cookie_def v9fs_cache_session_index_def = {
80 .name = "9P.session",
81 .type = FSCACHE_COOKIE_TYPE_INDEX,
82 .get_key = v9fs_cache_session_get_key,
83};
84
85void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses)
86{
87 /* If no cache session tag was specified, we generate a random one. */
88 if (!v9ses->cachetag)
89 v9fs_random_cachetag(v9ses);
90
91 v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index,
92 &v9fs_cache_session_index_def,
93 v9ses, true);
94 p9_debug(P9_DEBUG_FSC, "session %p get cookie %p\n",
95 v9ses, v9ses->fscache);
96}
97
98void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
99{
100 p9_debug(P9_DEBUG_FSC, "session %p put cookie %p\n",
101 v9ses, v9ses->fscache);
102 fscache_relinquish_cookie(v9ses->fscache, 0);
103 v9ses->fscache = NULL;
104}
105
106
107static uint16_t v9fs_cache_inode_get_key(const void *cookie_netfs_data,
108 void *buffer, uint16_t bufmax)
109{
110 const struct v9fs_inode *v9inode = cookie_netfs_data;
111 memcpy(buffer, &v9inode->qid.path, sizeof(v9inode->qid.path));
112 p9_debug(P9_DEBUG_FSC, "inode %p get key %llu\n",
113 &v9inode->vfs_inode, v9inode->qid.path);
114 return sizeof(v9inode->qid.path);
115}
116
117static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,
118 uint64_t *size)
119{
120 const struct v9fs_inode *v9inode = cookie_netfs_data;
121 *size = i_size_read(&v9inode->vfs_inode);
122
123 p9_debug(P9_DEBUG_FSC, "inode %p get attr %llu\n",
124 &v9inode->vfs_inode, *size);
125}
126
127static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,
128 void *buffer, uint16_t buflen)
129{
130 const struct v9fs_inode *v9inode = cookie_netfs_data;
131 memcpy(buffer, &v9inode->qid.version, sizeof(v9inode->qid.version));
132 p9_debug(P9_DEBUG_FSC, "inode %p get aux %u\n",
133 &v9inode->vfs_inode, v9inode->qid.version);
134 return sizeof(v9inode->qid.version);
135}
136
137static enum
138fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
139 const void *buffer,
140 uint16_t buflen)
141{
142 const struct v9fs_inode *v9inode = cookie_netfs_data;
143
144 if (buflen != sizeof(v9inode->qid.version))
145 return FSCACHE_CHECKAUX_OBSOLETE;
146
147 if (memcmp(buffer, &v9inode->qid.version,
148 sizeof(v9inode->qid.version)))
149 return FSCACHE_CHECKAUX_OBSOLETE;
150
151 return FSCACHE_CHECKAUX_OKAY;
152}
153
154static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
155{
156 struct v9fs_inode *v9inode = cookie_netfs_data;
157 struct pagevec pvec;
158 pgoff_t first;
159 int loop, nr_pages;
160
161 pagevec_init(&pvec, 0);
162 first = 0;
163
164 for (;;) {
165 nr_pages = pagevec_lookup(&pvec, v9inode->vfs_inode.i_mapping,
166 first,
167 PAGEVEC_SIZE - pagevec_count(&pvec));
168 if (!nr_pages)
169 break;
170
171 for (loop = 0; loop < nr_pages; loop++)
172 ClearPageFsCache(pvec.pages[loop]);
173
174 first = pvec.pages[nr_pages - 1]->index + 1;
175
176 pvec.nr = nr_pages;
177 pagevec_release(&pvec);
178 cond_resched();
179 }
180}
181
182const struct fscache_cookie_def v9fs_cache_inode_index_def = {
183 .name = "9p.inode",
184 .type = FSCACHE_COOKIE_TYPE_DATAFILE,
185 .get_key = v9fs_cache_inode_get_key,
186 .get_attr = v9fs_cache_inode_get_attr,
187 .get_aux = v9fs_cache_inode_get_aux,
188 .check_aux = v9fs_cache_inode_check_aux,
189 .now_uncached = v9fs_cache_inode_now_uncached,
190};
191
192void v9fs_cache_inode_get_cookie(struct inode *inode)
193{
194 struct v9fs_inode *v9inode;
195 struct v9fs_session_info *v9ses;
196
197 if (!S_ISREG(inode->i_mode))
198 return;
199
200 v9inode = V9FS_I(inode);
201 if (v9inode->fscache)
202 return;
203
204 v9ses = v9fs_inode2v9ses(inode);
205 v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
206 &v9fs_cache_inode_index_def,
207 v9inode, true);
208
209 p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n",
210 inode, v9inode->fscache);
211}
212
213void v9fs_cache_inode_put_cookie(struct inode *inode)
214{
215 struct v9fs_inode *v9inode = V9FS_I(inode);
216
217 if (!v9inode->fscache)
218 return;
219 p9_debug(P9_DEBUG_FSC, "inode %p put cookie %p\n",
220 inode, v9inode->fscache);
221
222 fscache_relinquish_cookie(v9inode->fscache, 0);
223 v9inode->fscache = NULL;
224}
225
226void v9fs_cache_inode_flush_cookie(struct inode *inode)
227{
228 struct v9fs_inode *v9inode = V9FS_I(inode);
229
230 if (!v9inode->fscache)
231 return;
232 p9_debug(P9_DEBUG_FSC, "inode %p flush cookie %p\n",
233 inode, v9inode->fscache);
234
235 fscache_relinquish_cookie(v9inode->fscache, 1);
236 v9inode->fscache = NULL;
237}
238
239void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp)
240{
241 struct v9fs_inode *v9inode = V9FS_I(inode);
242
243 if (!v9inode->fscache)
244 return;
245
246 mutex_lock(&v9inode->fscache_lock);
247
248 if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
249 v9fs_cache_inode_flush_cookie(inode);
250 else
251 v9fs_cache_inode_get_cookie(inode);
252
253 mutex_unlock(&v9inode->fscache_lock);
254}
255
256void v9fs_cache_inode_reset_cookie(struct inode *inode)
257{
258 struct v9fs_inode *v9inode = V9FS_I(inode);
259 struct v9fs_session_info *v9ses;
260 struct fscache_cookie *old;
261
262 if (!v9inode->fscache)
263 return;
264
265 old = v9inode->fscache;
266
267 mutex_lock(&v9inode->fscache_lock);
268 fscache_relinquish_cookie(v9inode->fscache, 1);
269
270 v9ses = v9fs_inode2v9ses(inode);
271 v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
272 &v9fs_cache_inode_index_def,
273 v9inode, true);
274 p9_debug(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p\n",
275 inode, old, v9inode->fscache);
276
277 mutex_unlock(&v9inode->fscache_lock);
278}
279
280int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
281{
282 struct inode *inode = page->mapping->host;
283 struct v9fs_inode *v9inode = V9FS_I(inode);
284
285 BUG_ON(!v9inode->fscache);
286
287 return fscache_maybe_release_page(v9inode->fscache, page, gfp);
288}
289
290void __v9fs_fscache_invalidate_page(struct page *page)
291{
292 struct inode *inode = page->mapping->host;
293 struct v9fs_inode *v9inode = V9FS_I(inode);
294
295 BUG_ON(!v9inode->fscache);
296
297 if (PageFsCache(page)) {
298 fscache_wait_on_page_write(v9inode->fscache, page);
299 BUG_ON(!PageLocked(page));
300 fscache_uncache_page(v9inode->fscache, page);
301 }
302}
303
304static void v9fs_vfs_readpage_complete(struct page *page, void *data,
305 int error)
306{
307 if (!error)
308 SetPageUptodate(page);
309
310 unlock_page(page);
311}
312
313/**
314 * __v9fs_readpage_from_fscache - read a page from cache
315 *
316 * Returns 0 if the pages are in cache and a BIO is submitted,
317 * 1 if the pages are not in cache and -error otherwise.
318 */
319
320int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page)
321{
322 int ret;
323 const struct v9fs_inode *v9inode = V9FS_I(inode);
324
325 p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
326 if (!v9inode->fscache)
327 return -ENOBUFS;
328
329 ret = fscache_read_or_alloc_page(v9inode->fscache,
330 page,
331 v9fs_vfs_readpage_complete,
332 NULL,
333 GFP_KERNEL);
334 switch (ret) {
335 case -ENOBUFS:
336 case -ENODATA:
337 p9_debug(P9_DEBUG_FSC, "page/inode not in cache %d\n", ret);
338 return 1;
339 case 0:
340 p9_debug(P9_DEBUG_FSC, "BIO submitted\n");
341 return ret;
342 default:
343 p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);
344 return ret;
345 }
346}
347
348/**
349 * __v9fs_readpages_from_fscache - read multiple pages from cache
350 *
351 * Returns 0 if the pages are in cache and a BIO is submitted,
352 * 1 if the pages are not in cache and -error otherwise.
353 */
354
355int __v9fs_readpages_from_fscache(struct inode *inode,
356 struct address_space *mapping,
357 struct list_head *pages,
358 unsigned *nr_pages)
359{
360 int ret;
361 const struct v9fs_inode *v9inode = V9FS_I(inode);
362
363 p9_debug(P9_DEBUG_FSC, "inode %p pages %u\n", inode, *nr_pages);
364 if (!v9inode->fscache)
365 return -ENOBUFS;
366
367 ret = fscache_read_or_alloc_pages(v9inode->fscache,
368 mapping, pages, nr_pages,
369 v9fs_vfs_readpage_complete,
370 NULL,
371 mapping_gfp_mask(mapping));
372 switch (ret) {
373 case -ENOBUFS:
374 case -ENODATA:
375 p9_debug(P9_DEBUG_FSC, "pages/inodes not in cache %d\n", ret);
376 return 1;
377 case 0:
378 BUG_ON(!list_empty(pages));
379 BUG_ON(*nr_pages != 0);
380 p9_debug(P9_DEBUG_FSC, "BIO submitted\n");
381 return ret;
382 default:
383 p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);
384 return ret;
385 }
386}
387
388/**
389 * __v9fs_readpage_to_fscache - write a page to the cache
390 *
391 */
392
393void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page)
394{
395 int ret;
396 const struct v9fs_inode *v9inode = V9FS_I(inode);
397
398 p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
399 ret = fscache_write_page(v9inode->fscache, page, GFP_KERNEL);
400 p9_debug(P9_DEBUG_FSC, "ret = %d\n", ret);
401 if (ret != 0)
402 v9fs_uncache_page(inode, page);
403}
404
405/*
406 * wait for a page to complete writing to the cache
407 */
408void __v9fs_fscache_wait_on_page_write(struct inode *inode, struct page *page)
409{
410 const struct v9fs_inode *v9inode = V9FS_I(inode);
411 p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
412 if (PageFsCache(page))
413 fscache_wait_on_page_write(v9inode->fscache, page);
414}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * V9FS cache definitions.
4 *
5 * Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu>
6 */
7
8#include <linux/jiffies.h>
9#include <linux/file.h>
10#include <linux/slab.h>
11#include <linux/stat.h>
12#include <linux/sched.h>
13#include <linux/fs.h>
14#include <net/9p/9p.h>
15
16#include "v9fs.h"
17#include "cache.h"
18
19int v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses,
20 const char *dev_name)
21{
22 struct fscache_volume *vcookie;
23 char *name, *p;
24
25 name = kasprintf(GFP_KERNEL, "9p,%s,%s",
26 dev_name, v9ses->cachetag ?: v9ses->aname);
27 if (!name)
28 return -ENOMEM;
29
30 for (p = name; *p; p++)
31 if (*p == '/')
32 *p = ';';
33
34 vcookie = fscache_acquire_volume(name, NULL, NULL, 0);
35 p9_debug(P9_DEBUG_FSC, "session %p get volume %p (%s)\n",
36 v9ses, vcookie, name);
37 if (IS_ERR(vcookie)) {
38 if (vcookie != ERR_PTR(-EBUSY)) {
39 kfree(name);
40 return PTR_ERR(vcookie);
41 }
42 pr_err("Cache volume key already in use (%s)\n", name);
43 vcookie = NULL;
44 }
45 v9ses->fscache = vcookie;
46 kfree(name);
47 return 0;
48}
49
50void v9fs_cache_inode_get_cookie(struct inode *inode)
51{
52 struct v9fs_inode *v9inode = V9FS_I(inode);
53 struct v9fs_session_info *v9ses;
54 __le32 version;
55 __le64 path;
56
57 if (!S_ISREG(inode->i_mode))
58 return;
59 if (WARN_ON(v9fs_inode_cookie(v9inode)))
60 return;
61
62 version = cpu_to_le32(v9inode->qid.version);
63 path = cpu_to_le64(v9inode->qid.path);
64 v9ses = v9fs_inode2v9ses(inode);
65 v9inode->netfs.cache =
66 fscache_acquire_cookie(v9fs_session_cache(v9ses),
67 0,
68 &path, sizeof(path),
69 &version, sizeof(version),
70 i_size_read(&v9inode->netfs.inode));
71 if (v9inode->netfs.cache)
72 mapping_set_release_always(inode->i_mapping);
73
74 p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n",
75 inode, v9fs_inode_cookie(v9inode));
76}