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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#include <linux/iversion.h>
22
23#include "internal.h"
24#include "iostat.h"
25#include "fscache.h"
26
27#define NFSDBG_FACILITY NFSDBG_FSCACHE
28
29static struct rb_root nfs_fscache_keys = RB_ROOT;
30static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
31
32/*
33 * Layout of the key for an NFS server cache object.
34 */
35struct nfs_server_key {
36 struct {
37 uint16_t nfsversion; /* NFS protocol version */
38 uint16_t family; /* address family */
39 __be16 port; /* IP port */
40 } hdr;
41 union {
42 struct in_addr ipv4_addr; /* IPv4 address */
43 struct in6_addr ipv6_addr; /* IPv6 address */
44 };
45} __packed;
46
47/*
48 * Get the per-client index cookie for an NFS client if the appropriate mount
49 * flag was set
50 * - We always try and get an index cookie for the client, but get filehandle
51 * cookies on a per-superblock basis, depending on the mount flags
52 */
53void nfs_fscache_get_client_cookie(struct nfs_client *clp)
54{
55 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
56 const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
57 struct nfs_server_key key;
58 uint16_t len = sizeof(key.hdr);
59
60 memset(&key, 0, sizeof(key));
61 key.hdr.nfsversion = clp->rpc_ops->version;
62 key.hdr.family = clp->cl_addr.ss_family;
63
64 switch (clp->cl_addr.ss_family) {
65 case AF_INET:
66 key.hdr.port = sin->sin_port;
67 key.ipv4_addr = sin->sin_addr;
68 len += sizeof(key.ipv4_addr);
69 break;
70
71 case AF_INET6:
72 key.hdr.port = sin6->sin6_port;
73 key.ipv6_addr = sin6->sin6_addr;
74 len += sizeof(key.ipv6_addr);
75 break;
76
77 default:
78 printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
79 clp->cl_addr.ss_family);
80 clp->fscache = NULL;
81 return;
82 }
83
84 /* create a cache index for looking up filehandles */
85 clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
86 &nfs_fscache_server_index_def,
87 &key, len,
88 NULL, 0,
89 clp, 0, true);
90 dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
91 clp, clp->fscache);
92}
93
94/*
95 * Dispose of a per-client cookie
96 */
97void nfs_fscache_release_client_cookie(struct nfs_client *clp)
98{
99 dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
100 clp, clp->fscache);
101
102 fscache_relinquish_cookie(clp->fscache, NULL, false);
103 clp->fscache = NULL;
104}
105
106/*
107 * Get the cache cookie for an NFS superblock. We have to handle
108 * uniquification here because the cache doesn't do it for us.
109 *
110 * The default uniquifier is just an empty string, but it may be overridden
111 * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
112 * superblock across an automount point of some nature.
113 */
114void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
115{
116 struct nfs_fscache_key *key, *xkey;
117 struct nfs_server *nfss = NFS_SB(sb);
118 struct rb_node **p, *parent;
119 int diff;
120
121 if (!uniq) {
122 uniq = "";
123 ulen = 1;
124 }
125
126 key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
127 if (!key)
128 return;
129
130 key->nfs_client = nfss->nfs_client;
131 key->key.super.s_flags = sb->s_flags & NFS_MS_MASK;
132 key->key.nfs_server.flags = nfss->flags;
133 key->key.nfs_server.rsize = nfss->rsize;
134 key->key.nfs_server.wsize = nfss->wsize;
135 key->key.nfs_server.acregmin = nfss->acregmin;
136 key->key.nfs_server.acregmax = nfss->acregmax;
137 key->key.nfs_server.acdirmin = nfss->acdirmin;
138 key->key.nfs_server.acdirmax = nfss->acdirmax;
139 key->key.nfs_server.fsid = nfss->fsid;
140 key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
141
142 key->key.uniq_len = ulen;
143 memcpy(key->key.uniquifier, uniq, ulen);
144
145 spin_lock(&nfs_fscache_keys_lock);
146 p = &nfs_fscache_keys.rb_node;
147 parent = NULL;
148 while (*p) {
149 parent = *p;
150 xkey = rb_entry(parent, struct nfs_fscache_key, node);
151
152 if (key->nfs_client < xkey->nfs_client)
153 goto go_left;
154 if (key->nfs_client > xkey->nfs_client)
155 goto go_right;
156
157 diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
158 if (diff < 0)
159 goto go_left;
160 if (diff > 0)
161 goto go_right;
162
163 if (key->key.uniq_len == 0)
164 goto non_unique;
165 diff = memcmp(key->key.uniquifier,
166 xkey->key.uniquifier,
167 key->key.uniq_len);
168 if (diff < 0)
169 goto go_left;
170 if (diff > 0)
171 goto go_right;
172 goto non_unique;
173
174 go_left:
175 p = &(*p)->rb_left;
176 continue;
177 go_right:
178 p = &(*p)->rb_right;
179 }
180
181 rb_link_node(&key->node, parent, p);
182 rb_insert_color(&key->node, &nfs_fscache_keys);
183 spin_unlock(&nfs_fscache_keys_lock);
184 nfss->fscache_key = key;
185
186 /* create a cache index for looking up filehandles */
187 nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
188 &nfs_fscache_super_index_def,
189 key, sizeof(*key) + ulen,
190 NULL, 0,
191 nfss, 0, true);
192 dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
193 nfss, nfss->fscache);
194 return;
195
196non_unique:
197 spin_unlock(&nfs_fscache_keys_lock);
198 kfree(key);
199 nfss->fscache_key = NULL;
200 nfss->fscache = NULL;
201 printk(KERN_WARNING "NFS:"
202 " Cache request denied due to non-unique superblock keys\n");
203}
204
205/*
206 * release a per-superblock cookie
207 */
208void nfs_fscache_release_super_cookie(struct super_block *sb)
209{
210 struct nfs_server *nfss = NFS_SB(sb);
211
212 dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
213 nfss, nfss->fscache);
214
215 fscache_relinquish_cookie(nfss->fscache, NULL, false);
216 nfss->fscache = NULL;
217
218 if (nfss->fscache_key) {
219 spin_lock(&nfs_fscache_keys_lock);
220 rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
221 spin_unlock(&nfs_fscache_keys_lock);
222 kfree(nfss->fscache_key);
223 nfss->fscache_key = NULL;
224 }
225}
226
227/*
228 * Initialise the per-inode cache cookie pointer for an NFS inode.
229 */
230void nfs_fscache_init_inode(struct inode *inode)
231{
232 struct nfs_fscache_inode_auxdata auxdata;
233 struct nfs_inode *nfsi = NFS_I(inode);
234
235 nfsi->fscache = NULL;
236 if (!S_ISREG(inode->i_mode))
237 return;
238
239 memset(&auxdata, 0, sizeof(auxdata));
240 auxdata.mtime = nfsi->vfs_inode.i_mtime;
241 auxdata.ctime = nfsi->vfs_inode.i_ctime;
242
243 if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
244 auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
245
246 nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache,
247 &nfs_fscache_inode_object_def,
248 nfsi->fh.data, nfsi->fh.size,
249 &auxdata, sizeof(auxdata),
250 nfsi, nfsi->vfs_inode.i_size, false);
251}
252
253/*
254 * Release a per-inode cookie.
255 */
256void nfs_fscache_clear_inode(struct inode *inode)
257{
258 struct nfs_fscache_inode_auxdata auxdata;
259 struct nfs_inode *nfsi = NFS_I(inode);
260 struct fscache_cookie *cookie = nfs_i_fscache(inode);
261
262 dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie);
263
264 memset(&auxdata, 0, sizeof(auxdata));
265 auxdata.mtime = nfsi->vfs_inode.i_mtime;
266 auxdata.ctime = nfsi->vfs_inode.i_ctime;
267 fscache_relinquish_cookie(cookie, &auxdata, false);
268 nfsi->fscache = NULL;
269}
270
271static bool nfs_fscache_can_enable(void *data)
272{
273 struct inode *inode = data;
274
275 return !inode_is_open_for_write(inode);
276}
277
278/*
279 * Enable or disable caching for a file that is being opened as appropriate.
280 * The cookie is allocated when the inode is initialised, but is not enabled at
281 * that time. Enablement is deferred to file-open time to avoid stat() and
282 * access() thrashing the cache.
283 *
284 * For now, with NFS, only regular files that are open read-only will be able
285 * to use the cache.
286 *
287 * We enable the cache for an inode if we open it read-only and it isn't
288 * currently open for writing. We disable the cache if the inode is open
289 * write-only.
290 *
291 * The caller uses the file struct to pin i_writecount on the inode before
292 * calling us when a file is opened for writing, so we can make use of that.
293 *
294 * Note that this may be invoked multiple times in parallel by parallel
295 * nfs_open() functions.
296 */
297void nfs_fscache_open_file(struct inode *inode, struct file *filp)
298{
299 struct nfs_fscache_inode_auxdata auxdata;
300 struct nfs_inode *nfsi = NFS_I(inode);
301 struct fscache_cookie *cookie = nfs_i_fscache(inode);
302
303 if (!fscache_cookie_valid(cookie))
304 return;
305
306 memset(&auxdata, 0, sizeof(auxdata));
307 auxdata.mtime = nfsi->vfs_inode.i_mtime;
308 auxdata.ctime = nfsi->vfs_inode.i_ctime;
309
310 if (inode_is_open_for_write(inode)) {
311 dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
312 clear_bit(NFS_INO_FSCACHE, &nfsi->flags);
313 fscache_disable_cookie(cookie, &auxdata, true);
314 fscache_uncache_all_inode_pages(cookie, inode);
315 } else {
316 dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
317 fscache_enable_cookie(cookie, &auxdata, nfsi->vfs_inode.i_size,
318 nfs_fscache_can_enable, inode);
319 if (fscache_cookie_enabled(cookie))
320 set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
321 }
322}
323EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
324
325/*
326 * Release the caching state associated with a page, if the page isn't busy
327 * interacting with the cache.
328 * - Returns true (can release page) or false (page busy).
329 */
330int nfs_fscache_release_page(struct page *page, gfp_t gfp)
331{
332 if (PageFsCache(page)) {
333 struct fscache_cookie *cookie = nfs_i_fscache(page->mapping->host);
334
335 BUG_ON(!cookie);
336 dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
337 cookie, page, NFS_I(page->mapping->host));
338
339 if (!fscache_maybe_release_page(cookie, page, gfp))
340 return 0;
341
342 nfs_inc_fscache_stats(page->mapping->host,
343 NFSIOS_FSCACHE_PAGES_UNCACHED);
344 }
345
346 return 1;
347}
348
349/*
350 * Release the caching state associated with a page if undergoing complete page
351 * invalidation.
352 */
353void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
354{
355 struct fscache_cookie *cookie = nfs_i_fscache(inode);
356
357 BUG_ON(!cookie);
358
359 dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
360 cookie, page, NFS_I(inode));
361
362 fscache_wait_on_page_write(cookie, page);
363
364 BUG_ON(!PageLocked(page));
365 fscache_uncache_page(cookie, page);
366 nfs_inc_fscache_stats(page->mapping->host,
367 NFSIOS_FSCACHE_PAGES_UNCACHED);
368}
369
370/*
371 * Handle completion of a page being read from the cache.
372 * - Called in process (keventd) context.
373 */
374static void nfs_readpage_from_fscache_complete(struct page *page,
375 void *context,
376 int error)
377{
378 dfprintk(FSCACHE,
379 "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
380 page, context, error);
381
382 /* if the read completes with an error, we just unlock the page and let
383 * the VM reissue the readpage */
384 if (!error) {
385 SetPageUptodate(page);
386 unlock_page(page);
387 } else {
388 error = nfs_readpage_async(context, page->mapping->host, page);
389 if (error)
390 unlock_page(page);
391 }
392}
393
394/*
395 * Retrieve a page from fscache
396 */
397int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
398 struct inode *inode, struct page *page)
399{
400 int ret;
401
402 dfprintk(FSCACHE,
403 "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
404 nfs_i_fscache(inode), page, page->index, page->flags, inode);
405
406 ret = fscache_read_or_alloc_page(nfs_i_fscache(inode),
407 page,
408 nfs_readpage_from_fscache_complete,
409 ctx,
410 GFP_KERNEL);
411
412 switch (ret) {
413 case 0: /* read BIO submitted (page in fscache) */
414 dfprintk(FSCACHE,
415 "NFS: readpage_from_fscache: BIO submitted\n");
416 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK);
417 return ret;
418
419 case -ENOBUFS: /* inode not in cache */
420 case -ENODATA: /* page not in cache */
421 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
422 dfprintk(FSCACHE,
423 "NFS: readpage_from_fscache %d\n", ret);
424 return 1;
425
426 default:
427 dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret);
428 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
429 }
430 return ret;
431}
432
433/*
434 * Retrieve a set of pages from fscache
435 */
436int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
437 struct inode *inode,
438 struct address_space *mapping,
439 struct list_head *pages,
440 unsigned *nr_pages)
441{
442 unsigned npages = *nr_pages;
443 int ret;
444
445 dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
446 nfs_i_fscache(inode), npages, inode);
447
448 ret = fscache_read_or_alloc_pages(nfs_i_fscache(inode),
449 mapping, pages, nr_pages,
450 nfs_readpage_from_fscache_complete,
451 ctx,
452 mapping_gfp_mask(mapping));
453 if (*nr_pages < npages)
454 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,
455 npages);
456 if (*nr_pages > 0)
457 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,
458 *nr_pages);
459
460 switch (ret) {
461 case 0: /* read submitted to the cache for all pages */
462 BUG_ON(!list_empty(pages));
463 BUG_ON(*nr_pages != 0);
464 dfprintk(FSCACHE,
465 "NFS: nfs_getpages_from_fscache: submitted\n");
466
467 return ret;
468
469 case -ENOBUFS: /* some pages aren't cached and can't be */
470 case -ENODATA: /* some pages aren't cached */
471 dfprintk(FSCACHE,
472 "NFS: nfs_getpages_from_fscache: no page: %d\n", ret);
473 return 1;
474
475 default:
476 dfprintk(FSCACHE,
477 "NFS: nfs_getpages_from_fscache: ret %d\n", ret);
478 }
479
480 return ret;
481}
482
483/*
484 * Store a newly fetched page in fscache
485 * - PG_fscache must be set on the page
486 */
487void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync)
488{
489 int ret;
490
491 dfprintk(FSCACHE,
492 "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n",
493 nfs_i_fscache(inode), page, page->index, page->flags, sync);
494
495 ret = fscache_write_page(nfs_i_fscache(inode), page,
496 inode->i_size, GFP_KERNEL);
497 dfprintk(FSCACHE,
498 "NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
499 page, page->index, page->flags, ret);
500
501 if (ret != 0) {
502 fscache_uncache_page(nfs_i_fscache(inode), page);
503 nfs_inc_fscache_stats(inode,
504 NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL);
505 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED);
506 } else {
507 nfs_inc_fscache_stats(inode,
508 NFSIOS_FSCACHE_PAGES_WRITTEN_OK);
509 }
510}
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}