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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#include <linux/xarray.h>
19#include <linux/fscache.h>
20#include <linux/netfs.h>
21
22#include "internal.h"
23#include "iostat.h"
24#include "fscache.h"
25#include "nfstrace.h"
26
27#define NFS_MAX_KEY_LEN 1000
28
29static bool nfs_append_int(char *key, int *_len, unsigned long long x)
30{
31 if (*_len > NFS_MAX_KEY_LEN)
32 return false;
33 if (x == 0)
34 key[(*_len)++] = ',';
35 else
36 *_len += sprintf(key + *_len, ",%llx", x);
37 return true;
38}
39
40/*
41 * Get the per-client index cookie for an NFS client if the appropriate mount
42 * flag was set
43 * - We always try and get an index cookie for the client, but get filehandle
44 * cookies on a per-superblock basis, depending on the mount flags
45 */
46static bool nfs_fscache_get_client_key(struct nfs_client *clp,
47 char *key, int *_len)
48{
49 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
50 const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
51
52 *_len += snprintf(key + *_len, NFS_MAX_KEY_LEN - *_len,
53 ",%u.%u,%x",
54 clp->rpc_ops->version,
55 clp->cl_minorversion,
56 clp->cl_addr.ss_family);
57
58 switch (clp->cl_addr.ss_family) {
59 case AF_INET:
60 if (!nfs_append_int(key, _len, sin->sin_port) ||
61 !nfs_append_int(key, _len, sin->sin_addr.s_addr))
62 return false;
63 return true;
64
65 case AF_INET6:
66 if (!nfs_append_int(key, _len, sin6->sin6_port) ||
67 !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[0]) ||
68 !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[1]) ||
69 !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[2]) ||
70 !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[3]))
71 return false;
72 return true;
73
74 default:
75 printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
76 clp->cl_addr.ss_family);
77 return false;
78 }
79}
80
81/*
82 * Get the cache cookie for an NFS superblock.
83 *
84 * The default uniquifier is just an empty string, but it may be overridden
85 * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
86 * superblock across an automount point of some nature.
87 */
88int nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
89{
90 struct fscache_volume *vcookie;
91 struct nfs_server *nfss = NFS_SB(sb);
92 unsigned int len = 3;
93 char *key;
94
95 if (uniq) {
96 nfss->fscache_uniq = kmemdup_nul(uniq, ulen, GFP_KERNEL);
97 if (!nfss->fscache_uniq)
98 return -ENOMEM;
99 }
100
101 key = kmalloc(NFS_MAX_KEY_LEN + 24, GFP_KERNEL);
102 if (!key)
103 return -ENOMEM;
104
105 memcpy(key, "nfs", 3);
106 if (!nfs_fscache_get_client_key(nfss->nfs_client, key, &len) ||
107 !nfs_append_int(key, &len, nfss->fsid.major) ||
108 !nfs_append_int(key, &len, nfss->fsid.minor) ||
109 !nfs_append_int(key, &len, sb->s_flags & NFS_SB_MASK) ||
110 !nfs_append_int(key, &len, nfss->flags) ||
111 !nfs_append_int(key, &len, nfss->rsize) ||
112 !nfs_append_int(key, &len, nfss->wsize) ||
113 !nfs_append_int(key, &len, nfss->acregmin) ||
114 !nfs_append_int(key, &len, nfss->acregmax) ||
115 !nfs_append_int(key, &len, nfss->acdirmin) ||
116 !nfs_append_int(key, &len, nfss->acdirmax) ||
117 !nfs_append_int(key, &len, nfss->client->cl_auth->au_flavor))
118 goto out;
119
120 if (ulen > 0) {
121 if (ulen > NFS_MAX_KEY_LEN - len)
122 goto out;
123 key[len++] = ',';
124 memcpy(key + len, uniq, ulen);
125 len += ulen;
126 }
127 key[len] = 0;
128
129 /* create a cache index for looking up filehandles */
130 vcookie = fscache_acquire_volume(key,
131 NULL, /* preferred_cache */
132 NULL, 0 /* coherency_data */);
133 if (IS_ERR(vcookie)) {
134 if (vcookie != ERR_PTR(-EBUSY)) {
135 kfree(key);
136 return PTR_ERR(vcookie);
137 }
138 pr_err("NFS: Cache volume key already in use (%s)\n", key);
139 vcookie = NULL;
140 }
141 nfss->fscache = vcookie;
142
143out:
144 kfree(key);
145 return 0;
146}
147
148/*
149 * release a per-superblock cookie
150 */
151void nfs_fscache_release_super_cookie(struct super_block *sb)
152{
153 struct nfs_server *nfss = NFS_SB(sb);
154
155 fscache_relinquish_volume(nfss->fscache, NULL, false);
156 nfss->fscache = NULL;
157 kfree(nfss->fscache_uniq);
158}
159
160/*
161 * Initialise the per-inode cache cookie pointer for an NFS inode.
162 */
163void nfs_fscache_init_inode(struct inode *inode)
164{
165 struct nfs_fscache_inode_auxdata auxdata;
166 struct nfs_server *nfss = NFS_SERVER(inode);
167 struct nfs_inode *nfsi = NFS_I(inode);
168
169 netfs_inode(inode)->cache = NULL;
170 if (!(nfss->fscache && S_ISREG(inode->i_mode)))
171 return;
172
173 nfs_fscache_update_auxdata(&auxdata, inode);
174
175 netfs_inode(inode)->cache = fscache_acquire_cookie(
176 nfss->fscache,
177 0,
178 nfsi->fh.data, /* index_key */
179 nfsi->fh.size,
180 &auxdata, /* aux_data */
181 sizeof(auxdata),
182 i_size_read(inode));
183
184 if (netfs_inode(inode)->cache)
185 mapping_set_release_always(inode->i_mapping);
186}
187
188/*
189 * Release a per-inode cookie.
190 */
191void nfs_fscache_clear_inode(struct inode *inode)
192{
193 fscache_relinquish_cookie(netfs_i_cookie(netfs_inode(inode)), false);
194 netfs_inode(inode)->cache = NULL;
195}
196
197/*
198 * Enable or disable caching for a file that is being opened as appropriate.
199 * The cookie is allocated when the inode is initialised, but is not enabled at
200 * that time. Enablement is deferred to file-open time to avoid stat() and
201 * access() thrashing the cache.
202 *
203 * For now, with NFS, only regular files that are open read-only will be able
204 * to use the cache.
205 *
206 * We enable the cache for an inode if we open it read-only and it isn't
207 * currently open for writing. We disable the cache if the inode is open
208 * write-only.
209 *
210 * The caller uses the file struct to pin i_writecount on the inode before
211 * calling us when a file is opened for writing, so we can make use of that.
212 *
213 * Note that this may be invoked multiple times in parallel by parallel
214 * nfs_open() functions.
215 */
216void nfs_fscache_open_file(struct inode *inode, struct file *filp)
217{
218 struct nfs_fscache_inode_auxdata auxdata;
219 struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode));
220 bool open_for_write = inode_is_open_for_write(inode);
221
222 if (!fscache_cookie_valid(cookie))
223 return;
224
225 fscache_use_cookie(cookie, open_for_write);
226 if (open_for_write) {
227 nfs_fscache_update_auxdata(&auxdata, inode);
228 fscache_invalidate(cookie, &auxdata, i_size_read(inode),
229 FSCACHE_INVAL_DIO_WRITE);
230 }
231}
232EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
233
234void nfs_fscache_release_file(struct inode *inode, struct file *filp)
235{
236 struct nfs_fscache_inode_auxdata auxdata;
237 struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode));
238 loff_t i_size = i_size_read(inode);
239
240 nfs_fscache_update_auxdata(&auxdata, inode);
241 fscache_unuse_cookie(cookie, &auxdata, &i_size);
242}
243
244int nfs_netfs_read_folio(struct file *file, struct folio *folio)
245{
246 if (!netfs_inode(folio_inode(folio))->cache)
247 return -ENOBUFS;
248
249 return netfs_read_folio(file, folio);
250}
251
252int nfs_netfs_readahead(struct readahead_control *ractl)
253{
254 struct inode *inode = ractl->mapping->host;
255
256 if (!netfs_inode(inode)->cache)
257 return -ENOBUFS;
258
259 netfs_readahead(ractl);
260 return 0;
261}
262
263static atomic_t nfs_netfs_debug_id;
264static int nfs_netfs_init_request(struct netfs_io_request *rreq, struct file *file)
265{
266 if (!file) {
267 if (WARN_ON_ONCE(rreq->origin != NETFS_PGPRIV2_COPY_TO_CACHE))
268 return -EIO;
269 return 0;
270 }
271
272 rreq->netfs_priv = get_nfs_open_context(nfs_file_open_context(file));
273 rreq->debug_id = atomic_inc_return(&nfs_netfs_debug_id);
274 /* [DEPRECATED] Use PG_private_2 to mark folio being written to the cache. */
275 __set_bit(NETFS_RREQ_USE_PGPRIV2, &rreq->flags);
276 rreq->io_streams[0].sreq_max_len = NFS_SB(rreq->inode->i_sb)->rsize;
277
278 return 0;
279}
280
281static void nfs_netfs_free_request(struct netfs_io_request *rreq)
282{
283 if (rreq->netfs_priv)
284 put_nfs_open_context(rreq->netfs_priv);
285}
286
287static struct nfs_netfs_io_data *nfs_netfs_alloc(struct netfs_io_subrequest *sreq)
288{
289 struct nfs_netfs_io_data *netfs;
290
291 netfs = kzalloc(sizeof(*netfs), GFP_KERNEL_ACCOUNT);
292 if (!netfs)
293 return NULL;
294 netfs->sreq = sreq;
295 refcount_set(&netfs->refcount, 1);
296 return netfs;
297}
298
299static void nfs_netfs_issue_read(struct netfs_io_subrequest *sreq)
300{
301 struct nfs_netfs_io_data *netfs;
302 struct nfs_pageio_descriptor pgio;
303 struct inode *inode = sreq->rreq->inode;
304 struct nfs_open_context *ctx = sreq->rreq->netfs_priv;
305 struct page *page;
306 unsigned long idx;
307 pgoff_t start, last;
308 int err;
309
310 start = (sreq->start + sreq->transferred) >> PAGE_SHIFT;
311 last = ((sreq->start + sreq->len - sreq->transferred - 1) >> PAGE_SHIFT);
312
313 nfs_pageio_init_read(&pgio, inode, false,
314 &nfs_async_read_completion_ops);
315
316 netfs = nfs_netfs_alloc(sreq);
317 if (!netfs)
318 return netfs_read_subreq_terminated(sreq, -ENOMEM, false);
319
320 pgio.pg_netfs = netfs; /* used in completion */
321
322 xa_for_each_range(&sreq->rreq->mapping->i_pages, idx, page, start, last) {
323 /* nfs_read_add_folio() may schedule() due to pNFS layout and other RPCs */
324 err = nfs_read_add_folio(&pgio, ctx, page_folio(page));
325 if (err < 0) {
326 netfs->error = err;
327 goto out;
328 }
329 }
330out:
331 nfs_pageio_complete_read(&pgio);
332 nfs_netfs_put(netfs);
333}
334
335void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr)
336{
337 struct nfs_netfs_io_data *netfs = hdr->netfs;
338
339 if (!netfs)
340 return;
341
342 nfs_netfs_get(netfs);
343}
344
345int nfs_netfs_folio_unlock(struct folio *folio)
346{
347 struct inode *inode = folio->mapping->host;
348
349 /*
350 * If fscache is enabled, netfs will unlock pages.
351 */
352 if (netfs_inode(inode)->cache)
353 return 0;
354
355 return 1;
356}
357
358void nfs_netfs_read_completion(struct nfs_pgio_header *hdr)
359{
360 struct nfs_netfs_io_data *netfs = hdr->netfs;
361 struct netfs_io_subrequest *sreq;
362
363 if (!netfs)
364 return;
365
366 sreq = netfs->sreq;
367 if (test_bit(NFS_IOHDR_EOF, &hdr->flags) &&
368 sreq->rreq->origin != NETFS_DIO_READ)
369 __set_bit(NETFS_SREQ_CLEAR_TAIL, &sreq->flags);
370
371 if (hdr->error)
372 netfs->error = hdr->error;
373 else
374 atomic64_add(hdr->res.count, &netfs->transferred);
375
376 nfs_netfs_put(netfs);
377 hdr->netfs = NULL;
378}
379
380const struct netfs_request_ops nfs_netfs_ops = {
381 .init_request = nfs_netfs_init_request,
382 .free_request = nfs_netfs_free_request,
383 .issue_read = nfs_netfs_issue_read,
384};
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}