blob: e777961939f3e6ed0354560c3e256247f6d24f66 [file] [log] [blame]
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>
25#include <linux/stat.h>
26#include <linux/sched.h>
27#include <linux/fs.h>
28#include <net/9p/9p.h>
29
30#include "v9fs.h"
31#include "cache.h"
32
33#define CACHETAG_LEN 11
34
35struct kmem_cache *vcookie_cache;
36
37struct fscache_netfs v9fs_cache_netfs = {
38 .name = "9p",
39 .version = 0,
40};
41
42static void init_once(void *foo)
43{
44 struct v9fs_cookie *vcookie = (struct v9fs_cookie *) foo;
45 vcookie->fscache = NULL;
46 vcookie->qid = NULL;
47 inode_init_once(&vcookie->inode);
48}
49
50/**
51 * v9fs_init_vcookiecache - initialize a cache for vcookies to maintain
52 * vcookie to inode mapping
53 *
54 * Returns 0 on success.
55 */
56
57static int v9fs_init_vcookiecache(void)
58{
59 vcookie_cache = kmem_cache_create("vcookie_cache",
60 sizeof(struct v9fs_cookie),
61 0, (SLAB_RECLAIM_ACCOUNT|
62 SLAB_MEM_SPREAD),
63 init_once);
64 if (!vcookie_cache)
65 return -ENOMEM;
66
67 return 0;
68}
69
70/**
71 * v9fs_destroy_vcookiecache - destroy the cache of vcookies
72 *
73 */
74
75static void v9fs_destroy_vcookiecache(void)
76{
77 kmem_cache_destroy(vcookie_cache);
78}
79
80int __v9fs_cache_register(void)
81{
82 int ret;
83 ret = v9fs_init_vcookiecache();
84 if (ret < 0)
85 return ret;
86
87 return fscache_register_netfs(&v9fs_cache_netfs);
88}
89
90void __v9fs_cache_unregister(void)
91{
92 v9fs_destroy_vcookiecache();
93 fscache_unregister_netfs(&v9fs_cache_netfs);
94}
95
96/**
97 * v9fs_random_cachetag - Generate a random tag to be associated
98 * with a new cache session.
99 *
100 * The value of jiffies is used for a fairly randomly cache tag.
101 */
102
103static
104int v9fs_random_cachetag(struct v9fs_session_info *v9ses)
105{
106 v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL);
107 if (!v9ses->cachetag)
108 return -ENOMEM;
109
110 return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies);
111}
112
113static uint16_t v9fs_cache_session_get_key(const void *cookie_netfs_data,
114 void *buffer, uint16_t bufmax)
115{
116 struct v9fs_session_info *v9ses;
117 uint16_t klen = 0;
118
119 v9ses = (struct v9fs_session_info *)cookie_netfs_data;
120 P9_DPRINTK(P9_DEBUG_FSC, "session %p buf %p size %u", v9ses,
121 buffer, bufmax);
122
123 if (v9ses->cachetag)
124 klen = strlen(v9ses->cachetag);
125
126 if (klen > bufmax)
127 return 0;
128
129 memcpy(buffer, v9ses->cachetag, klen);
130 P9_DPRINTK(P9_DEBUG_FSC, "cache session tag %s", v9ses->cachetag);
131 return klen;
132}
133
134const struct fscache_cookie_def v9fs_cache_session_index_def = {
135 .name = "9P.session",
136 .type = FSCACHE_COOKIE_TYPE_INDEX,
137 .get_key = v9fs_cache_session_get_key,
138};
139
140void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses)
141{
142 /* If no cache session tag was specified, we generate a random one. */
143 if (!v9ses->cachetag)
144 v9fs_random_cachetag(v9ses);
145
146 v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index,
147 &v9fs_cache_session_index_def,
148 v9ses);
149 P9_DPRINTK(P9_DEBUG_FSC, "session %p get cookie %p", v9ses,
150 v9ses->fscache);
151}
152
153void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
154{
155 P9_DPRINTK(P9_DEBUG_FSC, "session %p put cookie %p", v9ses,
156 v9ses->fscache);
157 fscache_relinquish_cookie(v9ses->fscache, 0);
158 v9ses->fscache = NULL;
159}
160
161
162static uint16_t v9fs_cache_inode_get_key(const void *cookie_netfs_data,
163 void *buffer, uint16_t bufmax)
164{
165 const struct v9fs_cookie *vcookie = cookie_netfs_data;
166 memcpy(buffer, &vcookie->qid->path, sizeof(vcookie->qid->path));
167
168 P9_DPRINTK(P9_DEBUG_FSC, "inode %p get key %llu", &vcookie->inode,
169 vcookie->qid->path);
170 return sizeof(vcookie->qid->path);
171}
172
173static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,
174 uint64_t *size)
175{
176 const struct v9fs_cookie *vcookie = cookie_netfs_data;
177 *size = i_size_read(&vcookie->inode);
178
179 P9_DPRINTK(P9_DEBUG_FSC, "inode %p get attr %llu", &vcookie->inode,
180 *size);
181}
182
183static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,
184 void *buffer, uint16_t buflen)
185{
186 const struct v9fs_cookie *vcookie = cookie_netfs_data;
187 memcpy(buffer, &vcookie->qid->version, sizeof(vcookie->qid->version));
188
189 P9_DPRINTK(P9_DEBUG_FSC, "inode %p get aux %u", &vcookie->inode,
190 vcookie->qid->version);
191 return sizeof(vcookie->qid->version);
192}
193
194static enum
195fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
196 const void *buffer,
197 uint16_t buflen)
198{
199 const struct v9fs_cookie *vcookie = cookie_netfs_data;
200
201 if (buflen != sizeof(vcookie->qid->version))
202 return FSCACHE_CHECKAUX_OBSOLETE;
203
204 if (memcmp(buffer, &vcookie->qid->version,
205 sizeof(vcookie->qid->version)))
206 return FSCACHE_CHECKAUX_OBSOLETE;
207
208 return FSCACHE_CHECKAUX_OKAY;
209}
210
211static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
212{
213 struct v9fs_cookie *vcookie = cookie_netfs_data;
214 struct pagevec pvec;
215 pgoff_t first;
216 int loop, nr_pages;
217
218 pagevec_init(&pvec, 0);
219 first = 0;
220
221 for (;;) {
222 nr_pages = pagevec_lookup(&pvec, vcookie->inode.i_mapping,
223 first,
224 PAGEVEC_SIZE - pagevec_count(&pvec));
225 if (!nr_pages)
226 break;
227
228 for (loop = 0; loop < nr_pages; loop++)
229 ClearPageFsCache(pvec.pages[loop]);
230
231 first = pvec.pages[nr_pages - 1]->index + 1;
232
233 pvec.nr = nr_pages;
234 pagevec_release(&pvec);
235 cond_resched();
236 }
237}
238
239const struct fscache_cookie_def v9fs_cache_inode_index_def = {
240 .name = "9p.inode",
241 .type = FSCACHE_COOKIE_TYPE_DATAFILE,
242 .get_key = v9fs_cache_inode_get_key,
243 .get_attr = v9fs_cache_inode_get_attr,
244 .get_aux = v9fs_cache_inode_get_aux,
245 .check_aux = v9fs_cache_inode_check_aux,
246 .now_uncached = v9fs_cache_inode_now_uncached,
247};
248
249void v9fs_cache_inode_get_cookie(struct inode *inode)
250{
251 struct v9fs_cookie *vcookie;
252 struct v9fs_session_info *v9ses;
253
254 if (!S_ISREG(inode->i_mode))
255 return;
256
257 vcookie = v9fs_inode2cookie(inode);
258 if (vcookie->fscache)
259 return;
260
261 v9ses = v9fs_inode2v9ses(inode);
262 vcookie->fscache = fscache_acquire_cookie(v9ses->fscache,
263 &v9fs_cache_inode_index_def,
264 vcookie);
265
266 P9_DPRINTK(P9_DEBUG_FSC, "inode %p get cookie %p", inode,
267 vcookie->fscache);
268}
269
270void v9fs_cache_inode_put_cookie(struct inode *inode)
271{
272 struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
273
274 if (!vcookie->fscache)
275 return;
276 P9_DPRINTK(P9_DEBUG_FSC, "inode %p put cookie %p", inode,
277 vcookie->fscache);
278
279 fscache_relinquish_cookie(vcookie->fscache, 0);
280 vcookie->fscache = NULL;
281}
282
283void v9fs_cache_inode_flush_cookie(struct inode *inode)
284{
285 struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
286
287 if (!vcookie->fscache)
288 return;
289 P9_DPRINTK(P9_DEBUG_FSC, "inode %p flush cookie %p", inode,
290 vcookie->fscache);
291
292 fscache_relinquish_cookie(vcookie->fscache, 1);
293 vcookie->fscache = NULL;
294}
295
296void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp)
297{
298 struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
299 struct p9_fid *fid;
300
301 if (!vcookie->fscache)
302 return;
303
304 spin_lock(&vcookie->lock);
305 fid = filp->private_data;
306 if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
307 v9fs_cache_inode_flush_cookie(inode);
308 else
309 v9fs_cache_inode_get_cookie(inode);
310
311 spin_unlock(&vcookie->lock);
312}
313
314void v9fs_cache_inode_reset_cookie(struct inode *inode)
315{
316 struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
317 struct v9fs_session_info *v9ses;
318 struct fscache_cookie *old;
319
320 if (!vcookie->fscache)
321 return;
322
323 old = vcookie->fscache;
324
325 spin_lock(&vcookie->lock);
326 fscache_relinquish_cookie(vcookie->fscache, 1);
327
328 v9ses = v9fs_inode2v9ses(inode);
329 vcookie->fscache = fscache_acquire_cookie(v9ses->fscache,
330 &v9fs_cache_inode_index_def,
331 vcookie);
332
333 P9_DPRINTK(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p",
334 inode, old, vcookie->fscache);
335
336 spin_unlock(&vcookie->lock);
337}
338
339int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
340{
341 struct inode *inode = page->mapping->host;
342 struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
343
344 BUG_ON(!vcookie->fscache);
345
David Howells6f054162009-12-01 13:38:45 +0000346 return fscache_maybe_release_page(vcookie->fscache, page, gfp);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500347}
348
349void __v9fs_fscache_invalidate_page(struct page *page)
350{
351 struct inode *inode = page->mapping->host;
352 struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
353
354 BUG_ON(!vcookie->fscache);
355
356 if (PageFsCache(page)) {
357 fscache_wait_on_page_write(vcookie->fscache, page);
358 BUG_ON(!PageLocked(page));
359 fscache_uncache_page(vcookie->fscache, page);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500360 }
361}
362
363static void v9fs_vfs_readpage_complete(struct page *page, void *data,
364 int error)
365{
366 if (!error)
367 SetPageUptodate(page);
368
369 unlock_page(page);
370}
371
372/**
373 * __v9fs_readpage_from_fscache - read a page from cache
374 *
375 * Returns 0 if the pages are in cache and a BIO is submitted,
376 * 1 if the pages are not in cache and -error otherwise.
377 */
378
379int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page)
380{
381 int ret;
382 const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
383
384 P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
385 if (!vcookie->fscache)
386 return -ENOBUFS;
387
388 ret = fscache_read_or_alloc_page(vcookie->fscache,
389 page,
390 v9fs_vfs_readpage_complete,
391 NULL,
392 GFP_KERNEL);
393 switch (ret) {
394 case -ENOBUFS:
395 case -ENODATA:
396 P9_DPRINTK(P9_DEBUG_FSC, "page/inode not in cache %d", ret);
397 return 1;
398 case 0:
399 P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
400 return ret;
401 default:
402 P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
403 return ret;
404 }
405}
406
407/**
408 * __v9fs_readpages_from_fscache - read multiple pages from cache
409 *
410 * Returns 0 if the pages are in cache and a BIO is submitted,
411 * 1 if the pages are not in cache and -error otherwise.
412 */
413
414int __v9fs_readpages_from_fscache(struct inode *inode,
415 struct address_space *mapping,
416 struct list_head *pages,
417 unsigned *nr_pages)
418{
419 int ret;
420 const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
421
422 P9_DPRINTK(P9_DEBUG_FSC, "inode %p pages %u", inode, *nr_pages);
423 if (!vcookie->fscache)
424 return -ENOBUFS;
425
426 ret = fscache_read_or_alloc_pages(vcookie->fscache,
427 mapping, pages, nr_pages,
428 v9fs_vfs_readpage_complete,
429 NULL,
430 mapping_gfp_mask(mapping));
431 switch (ret) {
432 case -ENOBUFS:
433 case -ENODATA:
434 P9_DPRINTK(P9_DEBUG_FSC, "pages/inodes not in cache %d", ret);
435 return 1;
436 case 0:
437 BUG_ON(!list_empty(pages));
438 BUG_ON(*nr_pages != 0);
439 P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
440 return ret;
441 default:
442 P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
443 return ret;
444 }
445}
446
447/**
448 * __v9fs_readpage_to_fscache - write a page to the cache
449 *
450 */
451
452void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page)
453{
454 int ret;
455 const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
456
457 P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
458 ret = fscache_write_page(vcookie->fscache, page, GFP_KERNEL);
459 P9_DPRINTK(P9_DEBUG_FSC, "ret = %d", ret);
460 if (ret != 0)
461 v9fs_uncache_page(inode, page);
462}