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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// SPDX-License-Identifier: GPL-2.0-or-later
2/* NFS filesystem cache interface
3 *
4 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#include <linux/init.h>
9#include <linux/kernel.h>
10#include <linux/sched.h>
11#include <linux/mm.h>
12#include <linux/nfs_fs.h>
13#include <linux/nfs_fs_sb.h>
14#include <linux/in6.h>
15#include <linux/seq_file.h>
16#include <linux/slab.h>
17#include <linux/iversion.h>
18
19#include "internal.h"
20#include "iostat.h"
21#include "fscache.h"
22#include "nfstrace.h"
23
24#define NFS_MAX_KEY_LEN 1000
25
26static bool nfs_append_int(char *key, int *_len, unsigned long long x)
27{
28 if (*_len > NFS_MAX_KEY_LEN)
29 return false;
30 if (x == 0)
31 key[(*_len)++] = ',';
32 else
33 *_len += sprintf(key + *_len, ",%llx", x);
34 return true;
35}
36
37/*
38 * Get the per-client index cookie for an NFS client if the appropriate mount
39 * flag was set
40 * - We always try and get an index cookie for the client, but get filehandle
41 * cookies on a per-superblock basis, depending on the mount flags
42 */
43static bool nfs_fscache_get_client_key(struct nfs_client *clp,
44 char *key, int *_len)
45{
46 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
47 const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
48
49 *_len += snprintf(key + *_len, NFS_MAX_KEY_LEN - *_len,
50 ",%u.%u,%x",
51 clp->rpc_ops->version,
52 clp->cl_minorversion,
53 clp->cl_addr.ss_family);
54
55 switch (clp->cl_addr.ss_family) {
56 case AF_INET:
57 if (!nfs_append_int(key, _len, sin->sin_port) ||
58 !nfs_append_int(key, _len, sin->sin_addr.s_addr))
59 return false;
60 return true;
61
62 case AF_INET6:
63 if (!nfs_append_int(key, _len, sin6->sin6_port) ||
64 !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[0]) ||
65 !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[1]) ||
66 !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[2]) ||
67 !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[3]))
68 return false;
69 return true;
70
71 default:
72 printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
73 clp->cl_addr.ss_family);
74 return false;
75 }
76}
77
78/*
79 * Get the cache cookie for an NFS superblock.
80 *
81 * The default uniquifier is just an empty string, but it may be overridden
82 * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
83 * superblock across an automount point of some nature.
84 */
85int nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
86{
87 struct fscache_volume *vcookie;
88 struct nfs_server *nfss = NFS_SB(sb);
89 unsigned int len = 3;
90 char *key;
91
92 if (uniq) {
93 nfss->fscache_uniq = kmemdup_nul(uniq, ulen, GFP_KERNEL);
94 if (!nfss->fscache_uniq)
95 return -ENOMEM;
96 }
97
98 key = kmalloc(NFS_MAX_KEY_LEN + 24, GFP_KERNEL);
99 if (!key)
100 return -ENOMEM;
101
102 memcpy(key, "nfs", 3);
103 if (!nfs_fscache_get_client_key(nfss->nfs_client, key, &len) ||
104 !nfs_append_int(key, &len, nfss->fsid.major) ||
105 !nfs_append_int(key, &len, nfss->fsid.minor) ||
106 !nfs_append_int(key, &len, sb->s_flags & NFS_SB_MASK) ||
107 !nfs_append_int(key, &len, nfss->flags) ||
108 !nfs_append_int(key, &len, nfss->rsize) ||
109 !nfs_append_int(key, &len, nfss->wsize) ||
110 !nfs_append_int(key, &len, nfss->acregmin) ||
111 !nfs_append_int(key, &len, nfss->acregmax) ||
112 !nfs_append_int(key, &len, nfss->acdirmin) ||
113 !nfs_append_int(key, &len, nfss->acdirmax) ||
114 !nfs_append_int(key, &len, nfss->client->cl_auth->au_flavor))
115 goto out;
116
117 if (ulen > 0) {
118 if (ulen > NFS_MAX_KEY_LEN - len)
119 goto out;
120 key[len++] = ',';
121 memcpy(key + len, uniq, ulen);
122 len += ulen;
123 }
124 key[len] = 0;
125
126 /* create a cache index for looking up filehandles */
127 vcookie = fscache_acquire_volume(key,
128 NULL, /* preferred_cache */
129 NULL, 0 /* coherency_data */);
130 if (IS_ERR(vcookie)) {
131 if (vcookie != ERR_PTR(-EBUSY)) {
132 kfree(key);
133 return PTR_ERR(vcookie);
134 }
135 pr_err("NFS: Cache volume key already in use (%s)\n", key);
136 vcookie = NULL;
137 }
138 nfss->fscache = vcookie;
139
140out:
141 kfree(key);
142 return 0;
143}
144
145/*
146 * release a per-superblock cookie
147 */
148void nfs_fscache_release_super_cookie(struct super_block *sb)
149{
150 struct nfs_server *nfss = NFS_SB(sb);
151
152 fscache_relinquish_volume(nfss->fscache, NULL, false);
153 nfss->fscache = NULL;
154 kfree(nfss->fscache_uniq);
155}
156
157/*
158 * Initialise the per-inode cache cookie pointer for an NFS inode.
159 */
160void nfs_fscache_init_inode(struct inode *inode)
161{
162 struct nfs_fscache_inode_auxdata auxdata;
163 struct nfs_server *nfss = NFS_SERVER(inode);
164 struct nfs_inode *nfsi = NFS_I(inode);
165
166 nfsi->fscache = NULL;
167 if (!(nfss->fscache && S_ISREG(inode->i_mode)))
168 return;
169
170 nfs_fscache_update_auxdata(&auxdata, inode);
171
172 nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache,
173 0,
174 nfsi->fh.data, /* index_key */
175 nfsi->fh.size,
176 &auxdata, /* aux_data */
177 sizeof(auxdata),
178 i_size_read(inode));
179}
180
181/*
182 * Release a per-inode cookie.
183 */
184void nfs_fscache_clear_inode(struct inode *inode)
185{
186 struct nfs_inode *nfsi = NFS_I(inode);
187 struct fscache_cookie *cookie = nfs_i_fscache(inode);
188
189 fscache_relinquish_cookie(cookie, false);
190 nfsi->fscache = NULL;
191}
192
193/*
194 * Enable or disable caching for a file that is being opened as appropriate.
195 * The cookie is allocated when the inode is initialised, but is not enabled at
196 * that time. Enablement is deferred to file-open time to avoid stat() and
197 * access() thrashing the cache.
198 *
199 * For now, with NFS, only regular files that are open read-only will be able
200 * to use the cache.
201 *
202 * We enable the cache for an inode if we open it read-only and it isn't
203 * currently open for writing. We disable the cache if the inode is open
204 * write-only.
205 *
206 * The caller uses the file struct to pin i_writecount on the inode before
207 * calling us when a file is opened for writing, so we can make use of that.
208 *
209 * Note that this may be invoked multiple times in parallel by parallel
210 * nfs_open() functions.
211 */
212void nfs_fscache_open_file(struct inode *inode, struct file *filp)
213{
214 struct nfs_fscache_inode_auxdata auxdata;
215 struct fscache_cookie *cookie = nfs_i_fscache(inode);
216 bool open_for_write = inode_is_open_for_write(inode);
217
218 if (!fscache_cookie_valid(cookie))
219 return;
220
221 fscache_use_cookie(cookie, open_for_write);
222 if (open_for_write) {
223 nfs_fscache_update_auxdata(&auxdata, inode);
224 fscache_invalidate(cookie, &auxdata, i_size_read(inode),
225 FSCACHE_INVAL_DIO_WRITE);
226 }
227}
228EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
229
230void nfs_fscache_release_file(struct inode *inode, struct file *filp)
231{
232 struct nfs_fscache_inode_auxdata auxdata;
233 struct fscache_cookie *cookie = nfs_i_fscache(inode);
234 loff_t i_size = i_size_read(inode);
235
236 nfs_fscache_update_auxdata(&auxdata, inode);
237 fscache_unuse_cookie(cookie, &auxdata, &i_size);
238}
239
240/*
241 * Fallback page reading interface.
242 */
243static int fscache_fallback_read_page(struct inode *inode, struct page *page)
244{
245 struct netfs_cache_resources cres;
246 struct fscache_cookie *cookie = nfs_i_fscache(inode);
247 struct iov_iter iter;
248 struct bio_vec bvec[1];
249 int ret;
250
251 memset(&cres, 0, sizeof(cres));
252 bvec[0].bv_page = page;
253 bvec[0].bv_offset = 0;
254 bvec[0].bv_len = PAGE_SIZE;
255 iov_iter_bvec(&iter, ITER_DEST, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
256
257 ret = fscache_begin_read_operation(&cres, cookie);
258 if (ret < 0)
259 return ret;
260
261 ret = fscache_read(&cres, page_offset(page), &iter, NETFS_READ_HOLE_FAIL,
262 NULL, NULL);
263 fscache_end_operation(&cres);
264 return ret;
265}
266
267/*
268 * Fallback page writing interface.
269 */
270static int fscache_fallback_write_page(struct inode *inode, struct page *page,
271 bool no_space_allocated_yet)
272{
273 struct netfs_cache_resources cres;
274 struct fscache_cookie *cookie = nfs_i_fscache(inode);
275 struct iov_iter iter;
276 struct bio_vec bvec[1];
277 loff_t start = page_offset(page);
278 size_t len = PAGE_SIZE;
279 int ret;
280
281 memset(&cres, 0, sizeof(cres));
282 bvec[0].bv_page = page;
283 bvec[0].bv_offset = 0;
284 bvec[0].bv_len = PAGE_SIZE;
285 iov_iter_bvec(&iter, ITER_SOURCE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
286
287 ret = fscache_begin_write_operation(&cres, cookie);
288 if (ret < 0)
289 return ret;
290
291 ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode),
292 no_space_allocated_yet);
293 if (ret == 0)
294 ret = fscache_write(&cres, page_offset(page), &iter, NULL, NULL);
295 fscache_end_operation(&cres);
296 return ret;
297}
298
299/*
300 * Retrieve a page from fscache
301 */
302int __nfs_fscache_read_page(struct inode *inode, struct page *page)
303{
304 int ret;
305
306 trace_nfs_fscache_read_page(inode, page);
307 if (PageChecked(page)) {
308 ClearPageChecked(page);
309 ret = 1;
310 goto out;
311 }
312
313 ret = fscache_fallback_read_page(inode, page);
314 if (ret < 0) {
315 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
316 SetPageChecked(page);
317 goto out;
318 }
319
320 /* Read completed synchronously */
321 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK);
322 SetPageUptodate(page);
323 ret = 0;
324out:
325 trace_nfs_fscache_read_page_exit(inode, page, ret);
326 return ret;
327}
328
329/*
330 * Store a newly fetched page in fscache. We can be certain there's no page
331 * stored in the cache as yet otherwise we would've read it from there.
332 */
333void __nfs_fscache_write_page(struct inode *inode, struct page *page)
334{
335 int ret;
336
337 trace_nfs_fscache_write_page(inode, page);
338
339 ret = fscache_fallback_write_page(inode, page, true);
340
341 if (ret != 0) {
342 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL);
343 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED);
344 } else {
345 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_WRITTEN_OK);
346 }
347 trace_nfs_fscache_write_page_exit(inode, page, ret);
348}