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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
72 p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n",
73 inode, v9fs_inode_cookie(v9inode));
74}
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
58const struct fscache_cookie_def v9fs_cache_session_index_def = {
59 .name = "9P.session",
60 .type = FSCACHE_COOKIE_TYPE_INDEX,
61};
62
63void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses)
64{
65 /* If no cache session tag was specified, we generate a random one. */
66 if (!v9ses->cachetag) {
67 if (v9fs_random_cachetag(v9ses) < 0) {
68 v9ses->fscache = NULL;
69 return;
70 }
71 }
72
73 v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index,
74 &v9fs_cache_session_index_def,
75 v9ses->cachetag,
76 strlen(v9ses->cachetag),
77 NULL, 0,
78 v9ses, 0, true);
79 p9_debug(P9_DEBUG_FSC, "session %p get cookie %p\n",
80 v9ses, v9ses->fscache);
81}
82
83void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
84{
85 p9_debug(P9_DEBUG_FSC, "session %p put cookie %p\n",
86 v9ses, v9ses->fscache);
87 fscache_relinquish_cookie(v9ses->fscache, NULL, false);
88 v9ses->fscache = NULL;
89}
90
91static enum
92fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
93 const void *buffer,
94 uint16_t buflen,
95 loff_t object_size)
96{
97 const struct v9fs_inode *v9inode = cookie_netfs_data;
98
99 if (buflen != sizeof(v9inode->qid.version))
100 return FSCACHE_CHECKAUX_OBSOLETE;
101
102 if (memcmp(buffer, &v9inode->qid.version,
103 sizeof(v9inode->qid.version)))
104 return FSCACHE_CHECKAUX_OBSOLETE;
105
106 return FSCACHE_CHECKAUX_OKAY;
107}
108
109const struct fscache_cookie_def v9fs_cache_inode_index_def = {
110 .name = "9p.inode",
111 .type = FSCACHE_COOKIE_TYPE_DATAFILE,
112 .check_aux = v9fs_cache_inode_check_aux,
113};
114
115void v9fs_cache_inode_get_cookie(struct inode *inode)
116{
117 struct v9fs_inode *v9inode;
118 struct v9fs_session_info *v9ses;
119
120 if (!S_ISREG(inode->i_mode))
121 return;
122
123 v9inode = V9FS_I(inode);
124 if (v9inode->fscache)
125 return;
126
127 v9ses = v9fs_inode2v9ses(inode);
128 v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
129 &v9fs_cache_inode_index_def,
130 &v9inode->qid.path,
131 sizeof(v9inode->qid.path),
132 &v9inode->qid.version,
133 sizeof(v9inode->qid.version),
134 v9inode,
135 i_size_read(&v9inode->vfs_inode),
136 true);
137
138 p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n",
139 inode, v9inode->fscache);
140}
141
142void v9fs_cache_inode_put_cookie(struct inode *inode)
143{
144 struct v9fs_inode *v9inode = V9FS_I(inode);
145
146 if (!v9inode->fscache)
147 return;
148 p9_debug(P9_DEBUG_FSC, "inode %p put cookie %p\n",
149 inode, v9inode->fscache);
150
151 fscache_relinquish_cookie(v9inode->fscache, &v9inode->qid.version,
152 false);
153 v9inode->fscache = NULL;
154}
155
156void v9fs_cache_inode_flush_cookie(struct inode *inode)
157{
158 struct v9fs_inode *v9inode = V9FS_I(inode);
159
160 if (!v9inode->fscache)
161 return;
162 p9_debug(P9_DEBUG_FSC, "inode %p flush cookie %p\n",
163 inode, v9inode->fscache);
164
165 fscache_relinquish_cookie(v9inode->fscache, NULL, true);
166 v9inode->fscache = NULL;
167}
168
169void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp)
170{
171 struct v9fs_inode *v9inode = V9FS_I(inode);
172
173 if (!v9inode->fscache)
174 return;
175
176 mutex_lock(&v9inode->fscache_lock);
177
178 if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
179 v9fs_cache_inode_flush_cookie(inode);
180 else
181 v9fs_cache_inode_get_cookie(inode);
182
183 mutex_unlock(&v9inode->fscache_lock);
184}
185
186void v9fs_cache_inode_reset_cookie(struct inode *inode)
187{
188 struct v9fs_inode *v9inode = V9FS_I(inode);
189 struct v9fs_session_info *v9ses;
190 struct fscache_cookie *old;
191
192 if (!v9inode->fscache)
193 return;
194
195 old = v9inode->fscache;
196
197 mutex_lock(&v9inode->fscache_lock);
198 fscache_relinquish_cookie(v9inode->fscache, NULL, true);
199
200 v9ses = v9fs_inode2v9ses(inode);
201 v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
202 &v9fs_cache_inode_index_def,
203 &v9inode->qid.path,
204 sizeof(v9inode->qid.path),
205 &v9inode->qid.version,
206 sizeof(v9inode->qid.version),
207 v9inode,
208 i_size_read(&v9inode->vfs_inode),
209 true);
210 p9_debug(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p\n",
211 inode, old, v9inode->fscache);
212
213 mutex_unlock(&v9inode->fscache_lock);
214}
215
216int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
217{
218 struct inode *inode = page->mapping->host;
219 struct v9fs_inode *v9inode = V9FS_I(inode);
220
221 BUG_ON(!v9inode->fscache);
222
223 return fscache_maybe_release_page(v9inode->fscache, page, gfp);
224}
225
226void __v9fs_fscache_invalidate_page(struct page *page)
227{
228 struct inode *inode = page->mapping->host;
229 struct v9fs_inode *v9inode = V9FS_I(inode);
230
231 BUG_ON(!v9inode->fscache);
232
233 if (PageFsCache(page)) {
234 fscache_wait_on_page_write(v9inode->fscache, page);
235 BUG_ON(!PageLocked(page));
236 fscache_uncache_page(v9inode->fscache, page);
237 }
238}
239
240static void v9fs_vfs_readpage_complete(struct page *page, void *data,
241 int error)
242{
243 if (!error)
244 SetPageUptodate(page);
245
246 unlock_page(page);
247}
248
249/**
250 * __v9fs_readpage_from_fscache - read a page from cache
251 *
252 * Returns 0 if the pages are in cache and a BIO is submitted,
253 * 1 if the pages are not in cache and -error otherwise.
254 */
255
256int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page)
257{
258 int ret;
259 const struct v9fs_inode *v9inode = V9FS_I(inode);
260
261 p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
262 if (!v9inode->fscache)
263 return -ENOBUFS;
264
265 ret = fscache_read_or_alloc_page(v9inode->fscache,
266 page,
267 v9fs_vfs_readpage_complete,
268 NULL,
269 GFP_KERNEL);
270 switch (ret) {
271 case -ENOBUFS:
272 case -ENODATA:
273 p9_debug(P9_DEBUG_FSC, "page/inode not in cache %d\n", ret);
274 return 1;
275 case 0:
276 p9_debug(P9_DEBUG_FSC, "BIO submitted\n");
277 return ret;
278 default:
279 p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);
280 return ret;
281 }
282}
283
284/**
285 * __v9fs_readpages_from_fscache - read multiple pages from cache
286 *
287 * Returns 0 if the pages are in cache and a BIO is submitted,
288 * 1 if the pages are not in cache and -error otherwise.
289 */
290
291int __v9fs_readpages_from_fscache(struct inode *inode,
292 struct address_space *mapping,
293 struct list_head *pages,
294 unsigned *nr_pages)
295{
296 int ret;
297 const struct v9fs_inode *v9inode = V9FS_I(inode);
298
299 p9_debug(P9_DEBUG_FSC, "inode %p pages %u\n", inode, *nr_pages);
300 if (!v9inode->fscache)
301 return -ENOBUFS;
302
303 ret = fscache_read_or_alloc_pages(v9inode->fscache,
304 mapping, pages, nr_pages,
305 v9fs_vfs_readpage_complete,
306 NULL,
307 mapping_gfp_mask(mapping));
308 switch (ret) {
309 case -ENOBUFS:
310 case -ENODATA:
311 p9_debug(P9_DEBUG_FSC, "pages/inodes not in cache %d\n", ret);
312 return 1;
313 case 0:
314 BUG_ON(!list_empty(pages));
315 BUG_ON(*nr_pages != 0);
316 p9_debug(P9_DEBUG_FSC, "BIO submitted\n");
317 return ret;
318 default:
319 p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);
320 return ret;
321 }
322}
323
324/**
325 * __v9fs_readpage_to_fscache - write a page to the cache
326 *
327 */
328
329void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page)
330{
331 int ret;
332 const struct v9fs_inode *v9inode = V9FS_I(inode);
333
334 p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
335 ret = fscache_write_page(v9inode->fscache, page,
336 i_size_read(&v9inode->vfs_inode), GFP_KERNEL);
337 p9_debug(P9_DEBUG_FSC, "ret = %d\n", ret);
338 if (ret != 0)
339 v9fs_uncache_page(inode, page);
340}
341
342/*
343 * wait for a page to complete writing to the cache
344 */
345void __v9fs_fscache_wait_on_page_write(struct inode *inode, struct page *page)
346{
347 const struct v9fs_inode *v9inode = V9FS_I(inode);
348 p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
349 if (PageFsCache(page))
350 fscache_wait_on_page_write(v9inode->fscache, page);
351}