1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* NFS filesystem cache interface definitions
3 *
4 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #ifndef _NFS_FSCACHE_H
9 #define _NFS_FSCACHE_H
10
11 #include <linux/swap.h>
12 #include <linux/nfs_fs.h>
13 #include <linux/nfs_mount.h>
14 #include <linux/nfs4_mount.h>
15 #include <linux/fscache.h>
16 #include <linux/iversion.h>
17
18 #ifdef CONFIG_NFS_FSCACHE
19
20 /*
21 * Definition of the auxiliary data attached to NFS inode storage objects
22 * within the cache.
23 *
24 * The contents of this struct are recorded in the on-disk local cache in the
25 * auxiliary data attached to the data storage object backing an inode. This
26 * permits coherency to be managed when a new inode binds to an already extant
27 * cache object.
28 */
29 struct nfs_fscache_inode_auxdata {
30 s64 mtime_sec;
31 s64 mtime_nsec;
32 s64 ctime_sec;
33 s64 ctime_nsec;
34 u64 change_attr;
35 };
36
37 struct nfs_netfs_io_data {
38 /*
39 * NFS may split a netfs_io_subrequest into multiple RPCs, each
40 * with their own read completion. In netfs, we can only call
41 * netfs_subreq_terminated() once for each subrequest. Use the
42 * refcount here to double as a marker of the last RPC completion,
43 * and only call netfs via netfs_subreq_terminated() once.
44 */
45 refcount_t refcount;
46 struct netfs_io_subrequest *sreq;
47
48 /*
49 * Final disposition of the netfs_io_subrequest, sent in
50 * netfs_subreq_terminated()
51 */
52 atomic64_t transferred;
53 int error;
54 };
55
56 static inline void nfs_netfs_get(struct nfs_netfs_io_data *netfs)
57 {
58 refcount_inc(&netfs->refcount);
59 }
60
61 static inline void nfs_netfs_put(struct nfs_netfs_io_data *netfs)
62 {
63 ssize_t final_len;
64
65 /* Only the last RPC completion should call netfs_subreq_terminated() */
66 if (!refcount_dec_and_test(&netfs->refcount))
67 return;
68
69 /*
70 * The NFS pageio interface may read a complete page, even when netfs
71 * only asked for a partial page. Specifically, this may be seen when
72 * one thread is truncating a file while another one is reading the last
73 * page of the file.
74 * Correct the final length here to be no larger than the netfs subrequest
75 * length, and thus avoid netfs's "Subreq overread" warning message.
76 */
77 final_len = min_t(s64, netfs->sreq->len, atomic64_read(&netfs->transferred));
78 netfs_subreq_terminated(netfs->sreq, netfs->error ?: final_len, false);
79 kfree(netfs);
80 }
81 static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi)
82 {
83 netfs_inode_init(&nfsi->netfs, &nfs_netfs_ops, false);
84 }
85 extern void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr);
86 extern void nfs_netfs_read_completion(struct nfs_pgio_header *hdr);
87 extern int nfs_netfs_folio_unlock(struct folio *folio);
88
89 /*
90 * fscache.c
91 */
92 extern int nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
93 extern void nfs_fscache_release_super_cookie(struct super_block *);
94
95 extern void nfs_fscache_init_inode(struct inode *);
96 extern void nfs_fscache_clear_inode(struct inode *);
97 extern void nfs_fscache_open_file(struct inode *, struct file *);
98 extern void nfs_fscache_release_file(struct inode *, struct file *);
99 extern int nfs_netfs_readahead(struct readahead_control *ractl);
100 extern int nfs_netfs_read_folio(struct file *file, struct folio *folio);
101
102 static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
103 {
104 if (folio_test_private_2(folio)) { /* [DEPRECATED] */
105 if (current_is_kswapd() || !(gfp & __GFP_FS))
106 return false;
107 folio_wait_private_2(folio);
108 }
109 fscache_note_page_release(netfs_i_cookie(netfs_inode(folio->mapping->host)));
110 return true;
111 }
112
113 static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata,
114 struct inode *inode)
115 {
116 memset(auxdata, 0, sizeof(*auxdata));
117 auxdata->mtime_sec = inode_get_mtime(inode).tv_sec;
118 auxdata->mtime_nsec = inode_get_mtime(inode).tv_nsec;
119 auxdata->ctime_sec = inode_get_ctime(inode).tv_sec;
120 auxdata->ctime_nsec = inode_get_ctime(inode).tv_nsec;
121
122 if (NFS_SERVER(inode)->nfs_client->rpc_ops->version == 4)
123 auxdata->change_attr = inode_peek_iversion_raw(inode);
124 }
125
126 /*
127 * Invalidate the contents of fscache for this inode. This will not sleep.
128 */
129 static inline void nfs_fscache_invalidate(struct inode *inode, int flags)
130 {
131 struct nfs_fscache_inode_auxdata auxdata;
132 struct fscache_cookie *cookie = netfs_i_cookie(&NFS_I(inode)->netfs);
133
134 nfs_fscache_update_auxdata(&auxdata, inode);
135 fscache_invalidate(cookie, &auxdata, i_size_read(inode), flags);
136 }
137
138 /*
139 * indicate the client caching state as readable text
140 */
141 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
142 {
143 if (server->fscache)
144 return "yes";
145 return "no ";
146 }
147
148 static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr,
149 struct nfs_pageio_descriptor *desc)
150 {
151 hdr->netfs = desc->pg_netfs;
152 }
153 static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc,
154 struct nfs_pgio_header *hdr)
155 {
156 desc->pg_netfs = hdr->netfs;
157 }
158 static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc)
159 {
160 desc->pg_netfs = NULL;
161 }
162 #else /* CONFIG_NFS_FSCACHE */
163 static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi) {}
164 static inline void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr) {}
165 static inline void nfs_netfs_read_completion(struct nfs_pgio_header *hdr) {}
166 static inline int nfs_netfs_folio_unlock(struct folio *folio)
167 {
168 return 1;
169 }
170 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
171
172 static inline void nfs_fscache_init_inode(struct inode *inode) {}
173 static inline void nfs_fscache_clear_inode(struct inode *inode) {}
174 static inline void nfs_fscache_open_file(struct inode *inode,
175 struct file *filp) {}
176 static inline void nfs_fscache_release_file(struct inode *inode, struct file *file) {}
177 static inline int nfs_netfs_readahead(struct readahead_control *ractl)
178 {
179 return -ENOBUFS;
180 }
181 static inline int nfs_netfs_read_folio(struct file *file, struct folio *folio)
182 {
183 return -ENOBUFS;
184 }
185
186 static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
187 {
188 return true; /* may release folio */
189 }
190 static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {}
191
192 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
193 {
194 return "no ";
195 }
196 static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr,
197 struct nfs_pageio_descriptor *desc) {}
198 static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc,
199 struct nfs_pgio_header *hdr) {}
200 static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc) {}
201 #endif /* CONFIG_NFS_FSCACHE */
202 #endif /* _NFS_FSCACHE_H */
203
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