blob: 51c94e26a346f1de790e4f3cac3e039d097c5494 [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
346 if (PageFsCache(page)) {
347 if (fscache_check_page_write(vcookie->fscache, page)) {
348 if (!(gfp & __GFP_WAIT))
349 return 0;
350 fscache_wait_on_page_write(vcookie->fscache, page);
351 }
352
353 fscache_uncache_page(vcookie->fscache, page);
354 ClearPageFsCache(page);
355 }
356
357 return 1;
358}
359
360void __v9fs_fscache_invalidate_page(struct page *page)
361{
362 struct inode *inode = page->mapping->host;
363 struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
364
365 BUG_ON(!vcookie->fscache);
366
367 if (PageFsCache(page)) {
368 fscache_wait_on_page_write(vcookie->fscache, page);
369 BUG_ON(!PageLocked(page));
370 fscache_uncache_page(vcookie->fscache, page);
371 ClearPageFsCache(page);
372 }
373}
374
375static void v9fs_vfs_readpage_complete(struct page *page, void *data,
376 int error)
377{
378 if (!error)
379 SetPageUptodate(page);
380
381 unlock_page(page);
382}
383
384/**
385 * __v9fs_readpage_from_fscache - read a page from cache
386 *
387 * Returns 0 if the pages are in cache and a BIO is submitted,
388 * 1 if the pages are not in cache and -error otherwise.
389 */
390
391int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page)
392{
393 int ret;
394 const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
395
396 P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
397 if (!vcookie->fscache)
398 return -ENOBUFS;
399
400 ret = fscache_read_or_alloc_page(vcookie->fscache,
401 page,
402 v9fs_vfs_readpage_complete,
403 NULL,
404 GFP_KERNEL);
405 switch (ret) {
406 case -ENOBUFS:
407 case -ENODATA:
408 P9_DPRINTK(P9_DEBUG_FSC, "page/inode not in cache %d", ret);
409 return 1;
410 case 0:
411 P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
412 return ret;
413 default:
414 P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
415 return ret;
416 }
417}
418
419/**
420 * __v9fs_readpages_from_fscache - read multiple pages from cache
421 *
422 * Returns 0 if the pages are in cache and a BIO is submitted,
423 * 1 if the pages are not in cache and -error otherwise.
424 */
425
426int __v9fs_readpages_from_fscache(struct inode *inode,
427 struct address_space *mapping,
428 struct list_head *pages,
429 unsigned *nr_pages)
430{
431 int ret;
432 const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
433
434 P9_DPRINTK(P9_DEBUG_FSC, "inode %p pages %u", inode, *nr_pages);
435 if (!vcookie->fscache)
436 return -ENOBUFS;
437
438 ret = fscache_read_or_alloc_pages(vcookie->fscache,
439 mapping, pages, nr_pages,
440 v9fs_vfs_readpage_complete,
441 NULL,
442 mapping_gfp_mask(mapping));
443 switch (ret) {
444 case -ENOBUFS:
445 case -ENODATA:
446 P9_DPRINTK(P9_DEBUG_FSC, "pages/inodes not in cache %d", ret);
447 return 1;
448 case 0:
449 BUG_ON(!list_empty(pages));
450 BUG_ON(*nr_pages != 0);
451 P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
452 return ret;
453 default:
454 P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
455 return ret;
456 }
457}
458
459/**
460 * __v9fs_readpage_to_fscache - write a page to the cache
461 *
462 */
463
464void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page)
465{
466 int ret;
467 const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
468
469 P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
470 ret = fscache_write_page(vcookie->fscache, page, GFP_KERNEL);
471 P9_DPRINTK(P9_DEBUG_FSC, "ret = %d", ret);
472 if (ret != 0)
473 v9fs_uncache_page(inode, page);
474}