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Abhishek Kulkarni60e78d22009-09-23 13:00:27 -05001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090025#include <linux/slab.h>
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050026#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
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050036struct fscache_netfs v9fs_cache_netfs = {
37 .name = "9p",
38 .version = 0,
39};
40
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050041/**
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_DPRINTK(P9_DEBUG_FSC, "session %p buf %p size %u", v9ses,
66 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_DPRINTK(P9_DEBUG_FSC, "cache session tag %s", v9ses->cachetag);
76 return klen;
77}
78
79const struct fscache_cookie_def v9fs_cache_session_index_def = {
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +053080 .name = "9P.session",
81 .type = FSCACHE_COOKIE_TYPE_INDEX,
82 .get_key = v9fs_cache_session_get_key,
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050083};
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);
94 P9_DPRINTK(P9_DEBUG_FSC, "session %p get cookie %p", v9ses,
95 v9ses->fscache);
96}
97
98void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
99{
100 P9_DPRINTK(P9_DEBUG_FSC, "session %p put cookie %p", v9ses,
101 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{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530110 const struct v9fs_inode *v9inode = cookie_netfs_data;
Aneesh Kumar K.Vfd2421f2011-07-11 16:40:59 +0000111 memcpy(buffer, &v9inode->qid.path, sizeof(v9inode->qid.path));
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530112 P9_DPRINTK(P9_DEBUG_FSC, "inode %p get key %llu", &v9inode->vfs_inode,
Aneesh Kumar K.Vfd2421f2011-07-11 16:40:59 +0000113 v9inode->qid.path);
114 return sizeof(v9inode->qid.path);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500115}
116
117static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,
118 uint64_t *size)
119{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530120 const struct v9fs_inode *v9inode = cookie_netfs_data;
121 *size = i_size_read(&v9inode->vfs_inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500122
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530123 P9_DPRINTK(P9_DEBUG_FSC, "inode %p get attr %llu", &v9inode->vfs_inode,
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500124 *size);
125}
126
127static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,
128 void *buffer, uint16_t buflen)
129{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530130 const struct v9fs_inode *v9inode = cookie_netfs_data;
Aneesh Kumar K.Vfd2421f2011-07-11 16:40:59 +0000131 memcpy(buffer, &v9inode->qid.version, sizeof(v9inode->qid.version));
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530132 P9_DPRINTK(P9_DEBUG_FSC, "inode %p get aux %u", &v9inode->vfs_inode,
Aneesh Kumar K.Vfd2421f2011-07-11 16:40:59 +0000133 v9inode->qid.version);
134 return sizeof(v9inode->qid.version);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500135}
136
137static enum
138fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
139 const void *buffer,
140 uint16_t buflen)
141{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530142 const struct v9fs_inode *v9inode = cookie_netfs_data;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500143
Aneesh Kumar K.Vfd2421f2011-07-11 16:40:59 +0000144 if (buflen != sizeof(v9inode->qid.version))
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500145 return FSCACHE_CHECKAUX_OBSOLETE;
146
Aneesh Kumar K.Vfd2421f2011-07-11 16:40:59 +0000147 if (memcmp(buffer, &v9inode->qid.version,
148 sizeof(v9inode->qid.version)))
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500149 return FSCACHE_CHECKAUX_OBSOLETE;
150
151 return FSCACHE_CHECKAUX_OKAY;
152}
153
154static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
155{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530156 struct v9fs_inode *v9inode = cookie_netfs_data;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500157 struct pagevec pvec;
158 pgoff_t first;
159 int loop, nr_pages;
160
161 pagevec_init(&pvec, 0);
162 first = 0;
163
164 for (;;) {
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530165 nr_pages = pagevec_lookup(&pvec, v9inode->vfs_inode.i_mapping,
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500166 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{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530194 struct v9fs_inode *v9inode;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500195 struct v9fs_session_info *v9ses;
196
197 if (!S_ISREG(inode->i_mode))
198 return;
199
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530200 v9inode = V9FS_I(inode);
201 if (v9inode->fscache)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500202 return;
203
204 v9ses = v9fs_inode2v9ses(inode);
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530205 v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500206 &v9fs_cache_inode_index_def,
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530207 v9inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500208
209 P9_DPRINTK(P9_DEBUG_FSC, "inode %p get cookie %p", inode,
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530210 v9inode->fscache);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500211}
212
213void v9fs_cache_inode_put_cookie(struct inode *inode)
214{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530215 struct v9fs_inode *v9inode = V9FS_I(inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500216
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530217 if (!v9inode->fscache)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500218 return;
219 P9_DPRINTK(P9_DEBUG_FSC, "inode %p put cookie %p", inode,
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530220 v9inode->fscache);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500221
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530222 fscache_relinquish_cookie(v9inode->fscache, 0);
223 v9inode->fscache = NULL;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500224}
225
226void v9fs_cache_inode_flush_cookie(struct inode *inode)
227{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530228 struct v9fs_inode *v9inode = V9FS_I(inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500229
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530230 if (!v9inode->fscache)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500231 return;
232 P9_DPRINTK(P9_DEBUG_FSC, "inode %p flush cookie %p", inode,
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530233 v9inode->fscache);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500234
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530235 fscache_relinquish_cookie(v9inode->fscache, 1);
236 v9inode->fscache = NULL;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500237}
238
239void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp)
240{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530241 struct v9fs_inode *v9inode = V9FS_I(inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500242 struct p9_fid *fid;
243
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530244 if (!v9inode->fscache)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500245 return;
246
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530247 spin_lock(&v9inode->fscache_lock);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500248 fid = filp->private_data;
249 if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
250 v9fs_cache_inode_flush_cookie(inode);
251 else
252 v9fs_cache_inode_get_cookie(inode);
253
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530254 spin_unlock(&v9inode->fscache_lock);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500255}
256
257void v9fs_cache_inode_reset_cookie(struct inode *inode)
258{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530259 struct v9fs_inode *v9inode = V9FS_I(inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500260 struct v9fs_session_info *v9ses;
261 struct fscache_cookie *old;
262
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530263 if (!v9inode->fscache)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500264 return;
265
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530266 old = v9inode->fscache;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500267
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530268 spin_lock(&v9inode->fscache_lock);
269 fscache_relinquish_cookie(v9inode->fscache, 1);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500270
271 v9ses = v9fs_inode2v9ses(inode);
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530272 v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500273 &v9fs_cache_inode_index_def,
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530274 v9inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500275 P9_DPRINTK(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p",
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530276 inode, old, v9inode->fscache);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500277
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530278 spin_unlock(&v9inode->fscache_lock);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500279}
280
281int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
282{
283 struct inode *inode = page->mapping->host;
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530284 struct v9fs_inode *v9inode = V9FS_I(inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500285
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530286 BUG_ON(!v9inode->fscache);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500287
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530288 return fscache_maybe_release_page(v9inode->fscache, page, gfp);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500289}
290
291void __v9fs_fscache_invalidate_page(struct page *page)
292{
293 struct inode *inode = page->mapping->host;
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530294 struct v9fs_inode *v9inode = V9FS_I(inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500295
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530296 BUG_ON(!v9inode->fscache);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500297
298 if (PageFsCache(page)) {
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530299 fscache_wait_on_page_write(v9inode->fscache, page);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500300 BUG_ON(!PageLocked(page));
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530301 fscache_uncache_page(v9inode->fscache, page);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500302 }
303}
304
305static void v9fs_vfs_readpage_complete(struct page *page, void *data,
306 int error)
307{
308 if (!error)
309 SetPageUptodate(page);
310
311 unlock_page(page);
312}
313
314/**
315 * __v9fs_readpage_from_fscache - read a page from cache
316 *
317 * Returns 0 if the pages are in cache and a BIO is submitted,
318 * 1 if the pages are not in cache and -error otherwise.
319 */
320
321int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page)
322{
323 int ret;
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530324 const struct v9fs_inode *v9inode = V9FS_I(inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500325
326 P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530327 if (!v9inode->fscache)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500328 return -ENOBUFS;
329
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530330 ret = fscache_read_or_alloc_page(v9inode->fscache,
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500331 page,
332 v9fs_vfs_readpage_complete,
333 NULL,
334 GFP_KERNEL);
335 switch (ret) {
336 case -ENOBUFS:
337 case -ENODATA:
338 P9_DPRINTK(P9_DEBUG_FSC, "page/inode not in cache %d", ret);
339 return 1;
340 case 0:
341 P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
342 return ret;
343 default:
344 P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
345 return ret;
346 }
347}
348
349/**
350 * __v9fs_readpages_from_fscache - read multiple pages from cache
351 *
352 * Returns 0 if the pages are in cache and a BIO is submitted,
353 * 1 if the pages are not in cache and -error otherwise.
354 */
355
356int __v9fs_readpages_from_fscache(struct inode *inode,
357 struct address_space *mapping,
358 struct list_head *pages,
359 unsigned *nr_pages)
360{
361 int ret;
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530362 const struct v9fs_inode *v9inode = V9FS_I(inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500363
364 P9_DPRINTK(P9_DEBUG_FSC, "inode %p pages %u", inode, *nr_pages);
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530365 if (!v9inode->fscache)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500366 return -ENOBUFS;
367
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530368 ret = fscache_read_or_alloc_pages(v9inode->fscache,
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500369 mapping, pages, nr_pages,
370 v9fs_vfs_readpage_complete,
371 NULL,
372 mapping_gfp_mask(mapping));
373 switch (ret) {
374 case -ENOBUFS:
375 case -ENODATA:
376 P9_DPRINTK(P9_DEBUG_FSC, "pages/inodes not in cache %d", ret);
377 return 1;
378 case 0:
379 BUG_ON(!list_empty(pages));
380 BUG_ON(*nr_pages != 0);
381 P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
382 return ret;
383 default:
384 P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
385 return ret;
386 }
387}
388
389/**
390 * __v9fs_readpage_to_fscache - write a page to the cache
391 *
392 */
393
394void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page)
395{
396 int ret;
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530397 const struct v9fs_inode *v9inode = V9FS_I(inode);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500398
399 P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530400 ret = fscache_write_page(v9inode->fscache, page, GFP_KERNEL);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500401 P9_DPRINTK(P9_DEBUG_FSC, "ret = %d", ret);
402 if (ret != 0)
403 v9fs_uncache_page(inode, page);
404}
Aneesh Kumar K.V2efda792011-02-28 17:03:56 +0530405
406/*
407 * wait for a page to complete writing to the cache
408 */
409void __v9fs_fscache_wait_on_page_write(struct inode *inode, struct page *page)
410{
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530411 const struct v9fs_inode *v9inode = V9FS_I(inode);
Aneesh Kumar K.V2efda792011-02-28 17:03:56 +0530412 P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
413 if (PageFsCache(page))
Aneesh Kumar K.Va78ce052011-02-28 17:04:02 +0530414 fscache_wait_on_page_write(v9inode->fscache, page);
Aneesh Kumar K.V2efda792011-02-28 17:03:56 +0530415}