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1/* NFS filesystem cache interface
2 *
3 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/sched.h>
15#include <linux/mm.h>
16#include <linux/nfs_fs.h>
17#include <linux/nfs_fs_sb.h>
18#include <linux/in6.h>
19#include <linux/seq_file.h>
20#include <linux/slab.h>
21
22#include "internal.h"
23#include "iostat.h"
24#include "fscache.h"
25
26#define NFSDBG_FACILITY NFSDBG_FSCACHE
27
28static struct rb_root nfs_fscache_keys = RB_ROOT;
29static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
30
31/*
32 * Get the per-client index cookie for an NFS client if the appropriate mount
33 * flag was set
34 * - We always try and get an index cookie for the client, but get filehandle
35 * cookies on a per-superblock basis, depending on the mount flags
36 */
37void nfs_fscache_get_client_cookie(struct nfs_client *clp)
38{
39 /* create a cache index for looking up filehandles */
40 clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
41 &nfs_fscache_server_index_def,
42 clp);
43 dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
44 clp, clp->fscache);
45}
46
47/*
48 * Dispose of a per-client cookie
49 */
50void nfs_fscache_release_client_cookie(struct nfs_client *clp)
51{
52 dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
53 clp, clp->fscache);
54
55 fscache_relinquish_cookie(clp->fscache, 0);
56 clp->fscache = NULL;
57}
58
59/*
60 * Get the cache cookie for an NFS superblock. We have to handle
61 * uniquification here because the cache doesn't do it for us.
62 *
63 * The default uniquifier is just an empty string, but it may be overridden
64 * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
65 * superblock across an automount point of some nature.
66 */
67void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq,
68 struct nfs_clone_mount *mntdata)
69{
70 struct nfs_fscache_key *key, *xkey;
71 struct nfs_server *nfss = NFS_SB(sb);
72 struct rb_node **p, *parent;
73 int diff, ulen;
74
75 if (uniq) {
76 ulen = strlen(uniq);
77 } else if (mntdata) {
78 struct nfs_server *mnt_s = NFS_SB(mntdata->sb);
79 if (mnt_s->fscache_key) {
80 uniq = mnt_s->fscache_key->key.uniquifier;
81 ulen = mnt_s->fscache_key->key.uniq_len;
82 }
83 }
84
85 if (!uniq) {
86 uniq = "";
87 ulen = 1;
88 }
89
90 key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
91 if (!key)
92 return;
93
94 key->nfs_client = nfss->nfs_client;
95 key->key.super.s_flags = sb->s_flags & NFS_MS_MASK;
96 key->key.nfs_server.flags = nfss->flags;
97 key->key.nfs_server.rsize = nfss->rsize;
98 key->key.nfs_server.wsize = nfss->wsize;
99 key->key.nfs_server.acregmin = nfss->acregmin;
100 key->key.nfs_server.acregmax = nfss->acregmax;
101 key->key.nfs_server.acdirmin = nfss->acdirmin;
102 key->key.nfs_server.acdirmax = nfss->acdirmax;
103 key->key.nfs_server.fsid = nfss->fsid;
104 key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
105
106 key->key.uniq_len = ulen;
107 memcpy(key->key.uniquifier, uniq, ulen);
108
109 spin_lock(&nfs_fscache_keys_lock);
110 p = &nfs_fscache_keys.rb_node;
111 parent = NULL;
112 while (*p) {
113 parent = *p;
114 xkey = rb_entry(parent, struct nfs_fscache_key, node);
115
116 if (key->nfs_client < xkey->nfs_client)
117 goto go_left;
118 if (key->nfs_client > xkey->nfs_client)
119 goto go_right;
120
121 diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
122 if (diff < 0)
123 goto go_left;
124 if (diff > 0)
125 goto go_right;
126
127 if (key->key.uniq_len == 0)
128 goto non_unique;
129 diff = memcmp(key->key.uniquifier,
130 xkey->key.uniquifier,
131 key->key.uniq_len);
132 if (diff < 0)
133 goto go_left;
134 if (diff > 0)
135 goto go_right;
136 goto non_unique;
137
138 go_left:
139 p = &(*p)->rb_left;
140 continue;
141 go_right:
142 p = &(*p)->rb_right;
143 }
144
145 rb_link_node(&key->node, parent, p);
146 rb_insert_color(&key->node, &nfs_fscache_keys);
147 spin_unlock(&nfs_fscache_keys_lock);
148 nfss->fscache_key = key;
149
150 /* create a cache index for looking up filehandles */
151 nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
152 &nfs_fscache_super_index_def,
153 nfss);
154 dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
155 nfss, nfss->fscache);
156 return;
157
158non_unique:
159 spin_unlock(&nfs_fscache_keys_lock);
160 kfree(key);
161 nfss->fscache_key = NULL;
162 nfss->fscache = NULL;
163 printk(KERN_WARNING "NFS:"
164 " Cache request denied due to non-unique superblock keys\n");
165}
166
167/*
168 * release a per-superblock cookie
169 */
170void nfs_fscache_release_super_cookie(struct super_block *sb)
171{
172 struct nfs_server *nfss = NFS_SB(sb);
173
174 dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
175 nfss, nfss->fscache);
176
177 fscache_relinquish_cookie(nfss->fscache, 0);
178 nfss->fscache = NULL;
179
180 if (nfss->fscache_key) {
181 spin_lock(&nfs_fscache_keys_lock);
182 rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
183 spin_unlock(&nfs_fscache_keys_lock);
184 kfree(nfss->fscache_key);
185 nfss->fscache_key = NULL;
186 }
187}
188
189/*
190 * Initialise the per-inode cache cookie pointer for an NFS inode.
191 */
192void nfs_fscache_init_inode_cookie(struct inode *inode)
193{
194 NFS_I(inode)->fscache = NULL;
195 if (S_ISREG(inode->i_mode))
196 set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
197}
198
199/*
200 * Get the per-inode cache cookie for an NFS inode.
201 */
202static void nfs_fscache_enable_inode_cookie(struct inode *inode)
203{
204 struct super_block *sb = inode->i_sb;
205 struct nfs_inode *nfsi = NFS_I(inode);
206
207 if (nfsi->fscache || !NFS_FSCACHE(inode))
208 return;
209
210 if ((NFS_SB(sb)->options & NFS_OPTION_FSCACHE)) {
211 nfsi->fscache = fscache_acquire_cookie(
212 NFS_SB(sb)->fscache,
213 &nfs_fscache_inode_object_def,
214 nfsi);
215
216 dfprintk(FSCACHE, "NFS: get FH cookie (0x%p/0x%p/0x%p)\n",
217 sb, nfsi, nfsi->fscache);
218 }
219}
220
221/*
222 * Release a per-inode cookie.
223 */
224void nfs_fscache_release_inode_cookie(struct inode *inode)
225{
226 struct nfs_inode *nfsi = NFS_I(inode);
227
228 dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n",
229 nfsi, nfsi->fscache);
230
231 fscache_relinquish_cookie(nfsi->fscache, 0);
232 nfsi->fscache = NULL;
233}
234
235/*
236 * Retire a per-inode cookie, destroying the data attached to it.
237 */
238void nfs_fscache_zap_inode_cookie(struct inode *inode)
239{
240 struct nfs_inode *nfsi = NFS_I(inode);
241
242 dfprintk(FSCACHE, "NFS: zapping cookie (0x%p/0x%p)\n",
243 nfsi, nfsi->fscache);
244
245 fscache_relinquish_cookie(nfsi->fscache, 1);
246 nfsi->fscache = NULL;
247}
248
249/*
250 * Turn off the cache with regard to a per-inode cookie if opened for writing,
251 * invalidating all the pages in the page cache relating to the associated
252 * inode to clear the per-page caching.
253 */
254static void nfs_fscache_disable_inode_cookie(struct inode *inode)
255{
256 clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
257
258 if (NFS_I(inode)->fscache) {
259 dfprintk(FSCACHE,
260 "NFS: nfsi 0x%p turning cache off\n", NFS_I(inode));
261
262 /* Need to uncache any pages attached to this inode that
263 * fscache knows about before turning off the cache.
264 */
265 fscache_uncache_all_inode_pages(NFS_I(inode)->fscache, inode);
266 nfs_fscache_zap_inode_cookie(inode);
267 }
268}
269
270/*
271 * wait_on_bit() sleep function for uninterruptible waiting
272 */
273static int nfs_fscache_wait_bit(void *flags)
274{
275 schedule();
276 return 0;
277}
278
279/*
280 * Lock against someone else trying to also acquire or relinquish a cookie
281 */
282static inline void nfs_fscache_inode_lock(struct inode *inode)
283{
284 struct nfs_inode *nfsi = NFS_I(inode);
285
286 while (test_and_set_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags))
287 wait_on_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK,
288 nfs_fscache_wait_bit, TASK_UNINTERRUPTIBLE);
289}
290
291/*
292 * Unlock cookie management lock
293 */
294static inline void nfs_fscache_inode_unlock(struct inode *inode)
295{
296 struct nfs_inode *nfsi = NFS_I(inode);
297
298 smp_mb__before_clear_bit();
299 clear_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags);
300 smp_mb__after_clear_bit();
301 wake_up_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK);
302}
303
304/*
305 * Decide if we should enable or disable local caching for this inode.
306 * - For now, with NFS, only regular files that are open read-only will be able
307 * to use the cache.
308 * - May be invoked multiple times in parallel by parallel nfs_open() functions.
309 */
310void nfs_fscache_set_inode_cookie(struct inode *inode, struct file *filp)
311{
312 if (NFS_FSCACHE(inode)) {
313 nfs_fscache_inode_lock(inode);
314 if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
315 nfs_fscache_disable_inode_cookie(inode);
316 else
317 nfs_fscache_enable_inode_cookie(inode);
318 nfs_fscache_inode_unlock(inode);
319 }
320}
321
322/*
323 * Replace a per-inode cookie due to revalidation detecting a file having
324 * changed on the server.
325 */
326void nfs_fscache_reset_inode_cookie(struct inode *inode)
327{
328 struct nfs_inode *nfsi = NFS_I(inode);
329 struct nfs_server *nfss = NFS_SERVER(inode);
330 struct fscache_cookie *old = nfsi->fscache;
331
332 nfs_fscache_inode_lock(inode);
333 if (nfsi->fscache) {
334 /* retire the current fscache cache and get a new one */
335 fscache_relinquish_cookie(nfsi->fscache, 1);
336
337 nfsi->fscache = fscache_acquire_cookie(
338 nfss->nfs_client->fscache,
339 &nfs_fscache_inode_object_def,
340 nfsi);
341
342 dfprintk(FSCACHE,
343 "NFS: revalidation new cookie (0x%p/0x%p/0x%p/0x%p)\n",
344 nfss, nfsi, old, nfsi->fscache);
345 }
346 nfs_fscache_inode_unlock(inode);
347}
348
349/*
350 * Release the caching state associated with a page, if the page isn't busy
351 * interacting with the cache.
352 * - Returns true (can release page) or false (page busy).
353 */
354int nfs_fscache_release_page(struct page *page, gfp_t gfp)
355{
356 if (PageFsCache(page)) {
357 struct nfs_inode *nfsi = NFS_I(page->mapping->host);
358 struct fscache_cookie *cookie = nfsi->fscache;
359
360 BUG_ON(!cookie);
361 dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
362 cookie, page, nfsi);
363
364 if (!fscache_maybe_release_page(cookie, page, gfp))
365 return 0;
366
367 nfs_add_fscache_stats(page->mapping->host,
368 NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
369 }
370
371 return 1;
372}
373
374/*
375 * Release the caching state associated with a page if undergoing complete page
376 * invalidation.
377 */
378void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
379{
380 struct nfs_inode *nfsi = NFS_I(inode);
381 struct fscache_cookie *cookie = nfsi->fscache;
382
383 BUG_ON(!cookie);
384
385 dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
386 cookie, page, nfsi);
387
388 fscache_wait_on_page_write(cookie, page);
389
390 BUG_ON(!PageLocked(page));
391 fscache_uncache_page(cookie, page);
392 nfs_add_fscache_stats(page->mapping->host,
393 NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
394}
395
396/*
397 * Handle completion of a page being read from the cache.
398 * - Called in process (keventd) context.
399 */
400static void nfs_readpage_from_fscache_complete(struct page *page,
401 void *context,
402 int error)
403{
404 dfprintk(FSCACHE,
405 "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
406 page, context, error);
407
408 /* if the read completes with an error, we just unlock the page and let
409 * the VM reissue the readpage */
410 if (!error) {
411 SetPageUptodate(page);
412 unlock_page(page);
413 } else {
414 error = nfs_readpage_async(context, page->mapping->host, page);
415 if (error)
416 unlock_page(page);
417 }
418}
419
420/*
421 * Retrieve a page from fscache
422 */
423int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
424 struct inode *inode, struct page *page)
425{
426 int ret;
427
428 dfprintk(FSCACHE,
429 "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
430 NFS_I(inode)->fscache, page, page->index, page->flags, inode);
431
432 ret = fscache_read_or_alloc_page(NFS_I(inode)->fscache,
433 page,
434 nfs_readpage_from_fscache_complete,
435 ctx,
436 GFP_KERNEL);
437
438 switch (ret) {
439 case 0: /* read BIO submitted (page in fscache) */
440 dfprintk(FSCACHE,
441 "NFS: readpage_from_fscache: BIO submitted\n");
442 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK, 1);
443 return ret;
444
445 case -ENOBUFS: /* inode not in cache */
446 case -ENODATA: /* page not in cache */
447 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1);
448 dfprintk(FSCACHE,
449 "NFS: readpage_from_fscache %d\n", ret);
450 return 1;
451
452 default:
453 dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret);
454 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1);
455 }
456 return ret;
457}
458
459/*
460 * Retrieve a set of pages from fscache
461 */
462int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
463 struct inode *inode,
464 struct address_space *mapping,
465 struct list_head *pages,
466 unsigned *nr_pages)
467{
468 unsigned npages = *nr_pages;
469 int ret;
470
471 dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
472 NFS_I(inode)->fscache, npages, inode);
473
474 ret = fscache_read_or_alloc_pages(NFS_I(inode)->fscache,
475 mapping, pages, nr_pages,
476 nfs_readpage_from_fscache_complete,
477 ctx,
478 mapping_gfp_mask(mapping));
479 if (*nr_pages < npages)
480 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,
481 npages);
482 if (*nr_pages > 0)
483 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,
484 *nr_pages);
485
486 switch (ret) {
487 case 0: /* read submitted to the cache for all pages */
488 BUG_ON(!list_empty(pages));
489 BUG_ON(*nr_pages != 0);
490 dfprintk(FSCACHE,
491 "NFS: nfs_getpages_from_fscache: submitted\n");
492
493 return ret;
494
495 case -ENOBUFS: /* some pages aren't cached and can't be */
496 case -ENODATA: /* some pages aren't cached */
497 dfprintk(FSCACHE,
498 "NFS: nfs_getpages_from_fscache: no page: %d\n", ret);
499 return 1;
500
501 default:
502 dfprintk(FSCACHE,
503 "NFS: nfs_getpages_from_fscache: ret %d\n", ret);
504 }
505
506 return ret;
507}
508
509/*
510 * Store a newly fetched page in fscache
511 * - PG_fscache must be set on the page
512 */
513void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync)
514{
515 int ret;
516
517 dfprintk(FSCACHE,
518 "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n",
519 NFS_I(inode)->fscache, page, page->index, page->flags, sync);
520
521 ret = fscache_write_page(NFS_I(inode)->fscache, page, GFP_KERNEL);
522 dfprintk(FSCACHE,
523 "NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
524 page, page->index, page->flags, ret);
525
526 if (ret != 0) {
527 fscache_uncache_page(NFS_I(inode)->fscache, page);
528 nfs_add_fscache_stats(inode,
529 NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL, 1);
530 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
531 } else {
532 nfs_add_fscache_stats(inode,
533 NFSIOS_FSCACHE_PAGES_WRITTEN_OK, 1);
534 }
535}
1/* NFS filesystem cache interface
2 *
3 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/sched.h>
15#include <linux/mm.h>
16#include <linux/nfs_fs.h>
17#include <linux/nfs_fs_sb.h>
18#include <linux/in6.h>
19#include <linux/seq_file.h>
20#include <linux/slab.h>
21
22#include "internal.h"
23#include "iostat.h"
24#include "fscache.h"
25
26#define NFSDBG_FACILITY NFSDBG_FSCACHE
27
28static struct rb_root nfs_fscache_keys = RB_ROOT;
29static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
30
31/*
32 * Get the per-client index cookie for an NFS client if the appropriate mount
33 * flag was set
34 * - We always try and get an index cookie for the client, but get filehandle
35 * cookies on a per-superblock basis, depending on the mount flags
36 */
37void nfs_fscache_get_client_cookie(struct nfs_client *clp)
38{
39 /* create a cache index for looking up filehandles */
40 clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
41 &nfs_fscache_server_index_def,
42 clp, true);
43 dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
44 clp, clp->fscache);
45}
46
47/*
48 * Dispose of a per-client cookie
49 */
50void nfs_fscache_release_client_cookie(struct nfs_client *clp)
51{
52 dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
53 clp, clp->fscache);
54
55 fscache_relinquish_cookie(clp->fscache, 0);
56 clp->fscache = NULL;
57}
58
59/*
60 * Get the cache cookie for an NFS superblock. We have to handle
61 * uniquification here because the cache doesn't do it for us.
62 *
63 * The default uniquifier is just an empty string, but it may be overridden
64 * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
65 * superblock across an automount point of some nature.
66 */
67void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
68{
69 struct nfs_fscache_key *key, *xkey;
70 struct nfs_server *nfss = NFS_SB(sb);
71 struct rb_node **p, *parent;
72 int diff;
73
74 if (!uniq) {
75 uniq = "";
76 ulen = 1;
77 }
78
79 key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
80 if (!key)
81 return;
82
83 key->nfs_client = nfss->nfs_client;
84 key->key.super.s_flags = sb->s_flags & NFS_MS_MASK;
85 key->key.nfs_server.flags = nfss->flags;
86 key->key.nfs_server.rsize = nfss->rsize;
87 key->key.nfs_server.wsize = nfss->wsize;
88 key->key.nfs_server.acregmin = nfss->acregmin;
89 key->key.nfs_server.acregmax = nfss->acregmax;
90 key->key.nfs_server.acdirmin = nfss->acdirmin;
91 key->key.nfs_server.acdirmax = nfss->acdirmax;
92 key->key.nfs_server.fsid = nfss->fsid;
93 key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
94
95 key->key.uniq_len = ulen;
96 memcpy(key->key.uniquifier, uniq, ulen);
97
98 spin_lock(&nfs_fscache_keys_lock);
99 p = &nfs_fscache_keys.rb_node;
100 parent = NULL;
101 while (*p) {
102 parent = *p;
103 xkey = rb_entry(parent, struct nfs_fscache_key, node);
104
105 if (key->nfs_client < xkey->nfs_client)
106 goto go_left;
107 if (key->nfs_client > xkey->nfs_client)
108 goto go_right;
109
110 diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
111 if (diff < 0)
112 goto go_left;
113 if (diff > 0)
114 goto go_right;
115
116 if (key->key.uniq_len == 0)
117 goto non_unique;
118 diff = memcmp(key->key.uniquifier,
119 xkey->key.uniquifier,
120 key->key.uniq_len);
121 if (diff < 0)
122 goto go_left;
123 if (diff > 0)
124 goto go_right;
125 goto non_unique;
126
127 go_left:
128 p = &(*p)->rb_left;
129 continue;
130 go_right:
131 p = &(*p)->rb_right;
132 }
133
134 rb_link_node(&key->node, parent, p);
135 rb_insert_color(&key->node, &nfs_fscache_keys);
136 spin_unlock(&nfs_fscache_keys_lock);
137 nfss->fscache_key = key;
138
139 /* create a cache index for looking up filehandles */
140 nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
141 &nfs_fscache_super_index_def,
142 nfss, true);
143 dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
144 nfss, nfss->fscache);
145 return;
146
147non_unique:
148 spin_unlock(&nfs_fscache_keys_lock);
149 kfree(key);
150 nfss->fscache_key = NULL;
151 nfss->fscache = NULL;
152 printk(KERN_WARNING "NFS:"
153 " Cache request denied due to non-unique superblock keys\n");
154}
155
156/*
157 * release a per-superblock cookie
158 */
159void nfs_fscache_release_super_cookie(struct super_block *sb)
160{
161 struct nfs_server *nfss = NFS_SB(sb);
162
163 dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
164 nfss, nfss->fscache);
165
166 fscache_relinquish_cookie(nfss->fscache, 0);
167 nfss->fscache = NULL;
168
169 if (nfss->fscache_key) {
170 spin_lock(&nfs_fscache_keys_lock);
171 rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
172 spin_unlock(&nfs_fscache_keys_lock);
173 kfree(nfss->fscache_key);
174 nfss->fscache_key = NULL;
175 }
176}
177
178/*
179 * Initialise the per-inode cache cookie pointer for an NFS inode.
180 */
181void nfs_fscache_init_inode(struct inode *inode)
182{
183 struct nfs_inode *nfsi = NFS_I(inode);
184
185 nfsi->fscache = NULL;
186 if (!S_ISREG(inode->i_mode))
187 return;
188 nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache,
189 &nfs_fscache_inode_object_def,
190 nfsi, false);
191}
192
193/*
194 * Release a per-inode cookie.
195 */
196void nfs_fscache_clear_inode(struct inode *inode)
197{
198 struct nfs_inode *nfsi = NFS_I(inode);
199 struct fscache_cookie *cookie = nfs_i_fscache(inode);
200
201 dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie);
202
203 fscache_relinquish_cookie(cookie, false);
204 nfsi->fscache = NULL;
205}
206
207static bool nfs_fscache_can_enable(void *data)
208{
209 struct inode *inode = data;
210
211 return !inode_is_open_for_write(inode);
212}
213
214/*
215 * Enable or disable caching for a file that is being opened as appropriate.
216 * The cookie is allocated when the inode is initialised, but is not enabled at
217 * that time. Enablement is deferred to file-open time to avoid stat() and
218 * access() thrashing the cache.
219 *
220 * For now, with NFS, only regular files that are open read-only will be able
221 * to use the cache.
222 *
223 * We enable the cache for an inode if we open it read-only and it isn't
224 * currently open for writing. We disable the cache if the inode is open
225 * write-only.
226 *
227 * The caller uses the file struct to pin i_writecount on the inode before
228 * calling us when a file is opened for writing, so we can make use of that.
229 *
230 * Note that this may be invoked multiple times in parallel by parallel
231 * nfs_open() functions.
232 */
233void nfs_fscache_open_file(struct inode *inode, struct file *filp)
234{
235 struct nfs_inode *nfsi = NFS_I(inode);
236 struct fscache_cookie *cookie = nfs_i_fscache(inode);
237
238 if (!fscache_cookie_valid(cookie))
239 return;
240
241 if (inode_is_open_for_write(inode)) {
242 dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
243 clear_bit(NFS_INO_FSCACHE, &nfsi->flags);
244 fscache_disable_cookie(cookie, true);
245 fscache_uncache_all_inode_pages(cookie, inode);
246 } else {
247 dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
248 fscache_enable_cookie(cookie, nfs_fscache_can_enable, inode);
249 if (fscache_cookie_enabled(cookie))
250 set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
251 }
252}
253EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
254
255/*
256 * Release the caching state associated with a page, if the page isn't busy
257 * interacting with the cache.
258 * - Returns true (can release page) or false (page busy).
259 */
260int nfs_fscache_release_page(struct page *page, gfp_t gfp)
261{
262 if (PageFsCache(page)) {
263 struct fscache_cookie *cookie = nfs_i_fscache(page->mapping->host);
264
265 BUG_ON(!cookie);
266 dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
267 cookie, page, NFS_I(page->mapping->host));
268
269 if (!fscache_maybe_release_page(cookie, page, gfp))
270 return 0;
271
272 nfs_inc_fscache_stats(page->mapping->host,
273 NFSIOS_FSCACHE_PAGES_UNCACHED);
274 }
275
276 return 1;
277}
278
279/*
280 * Release the caching state associated with a page if undergoing complete page
281 * invalidation.
282 */
283void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
284{
285 struct fscache_cookie *cookie = nfs_i_fscache(inode);
286
287 BUG_ON(!cookie);
288
289 dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
290 cookie, page, NFS_I(inode));
291
292 fscache_wait_on_page_write(cookie, page);
293
294 BUG_ON(!PageLocked(page));
295 fscache_uncache_page(cookie, page);
296 nfs_inc_fscache_stats(page->mapping->host,
297 NFSIOS_FSCACHE_PAGES_UNCACHED);
298}
299
300/*
301 * Handle completion of a page being read from the cache.
302 * - Called in process (keventd) context.
303 */
304static void nfs_readpage_from_fscache_complete(struct page *page,
305 void *context,
306 int error)
307{
308 dfprintk(FSCACHE,
309 "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
310 page, context, error);
311
312 /* if the read completes with an error, we just unlock the page and let
313 * the VM reissue the readpage */
314 if (!error) {
315 SetPageUptodate(page);
316 unlock_page(page);
317 } else {
318 error = nfs_readpage_async(context, page->mapping->host, page);
319 if (error)
320 unlock_page(page);
321 }
322}
323
324/*
325 * Retrieve a page from fscache
326 */
327int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
328 struct inode *inode, struct page *page)
329{
330 int ret;
331
332 dfprintk(FSCACHE,
333 "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
334 nfs_i_fscache(inode), page, page->index, page->flags, inode);
335
336 ret = fscache_read_or_alloc_page(nfs_i_fscache(inode),
337 page,
338 nfs_readpage_from_fscache_complete,
339 ctx,
340 GFP_KERNEL);
341
342 switch (ret) {
343 case 0: /* read BIO submitted (page in fscache) */
344 dfprintk(FSCACHE,
345 "NFS: readpage_from_fscache: BIO submitted\n");
346 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK);
347 return ret;
348
349 case -ENOBUFS: /* inode not in cache */
350 case -ENODATA: /* page not in cache */
351 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
352 dfprintk(FSCACHE,
353 "NFS: readpage_from_fscache %d\n", ret);
354 return 1;
355
356 default:
357 dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret);
358 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
359 }
360 return ret;
361}
362
363/*
364 * Retrieve a set of pages from fscache
365 */
366int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
367 struct inode *inode,
368 struct address_space *mapping,
369 struct list_head *pages,
370 unsigned *nr_pages)
371{
372 unsigned npages = *nr_pages;
373 int ret;
374
375 dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
376 nfs_i_fscache(inode), npages, inode);
377
378 ret = fscache_read_or_alloc_pages(nfs_i_fscache(inode),
379 mapping, pages, nr_pages,
380 nfs_readpage_from_fscache_complete,
381 ctx,
382 mapping_gfp_mask(mapping));
383 if (*nr_pages < npages)
384 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,
385 npages);
386 if (*nr_pages > 0)
387 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,
388 *nr_pages);
389
390 switch (ret) {
391 case 0: /* read submitted to the cache for all pages */
392 BUG_ON(!list_empty(pages));
393 BUG_ON(*nr_pages != 0);
394 dfprintk(FSCACHE,
395 "NFS: nfs_getpages_from_fscache: submitted\n");
396
397 return ret;
398
399 case -ENOBUFS: /* some pages aren't cached and can't be */
400 case -ENODATA: /* some pages aren't cached */
401 dfprintk(FSCACHE,
402 "NFS: nfs_getpages_from_fscache: no page: %d\n", ret);
403 return 1;
404
405 default:
406 dfprintk(FSCACHE,
407 "NFS: nfs_getpages_from_fscache: ret %d\n", ret);
408 }
409
410 return ret;
411}
412
413/*
414 * Store a newly fetched page in fscache
415 * - PG_fscache must be set on the page
416 */
417void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync)
418{
419 int ret;
420
421 dfprintk(FSCACHE,
422 "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n",
423 nfs_i_fscache(inode), page, page->index, page->flags, sync);
424
425 ret = fscache_write_page(nfs_i_fscache(inode), page, GFP_KERNEL);
426 dfprintk(FSCACHE,
427 "NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
428 page, page->index, page->flags, ret);
429
430 if (ret != 0) {
431 fscache_uncache_page(nfs_i_fscache(inode), page);
432 nfs_inc_fscache_stats(inode,
433 NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL);
434 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED);
435 } else {
436 nfs_inc_fscache_stats(inode,
437 NFSIOS_FSCACHE_PAGES_WRITTEN_OK);
438 }
439}