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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* NFS FS-Cache index structure definition
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/iversion.h>
16
17#include "internal.h"
18#include "fscache.h"
19
20#define NFSDBG_FACILITY NFSDBG_FSCACHE
21
22/*
23 * Define the NFS filesystem for FS-Cache. Upon registration FS-Cache sticks
24 * the cookie for the top-level index object for NFS into here. The top-level
25 * index can than have other cache objects inserted into it.
26 */
27struct fscache_netfs nfs_fscache_netfs = {
28 .name = "nfs",
29 .version = 0,
30};
31
32/*
33 * Register NFS for caching
34 */
35int nfs_fscache_register(void)
36{
37 return fscache_register_netfs(&nfs_fscache_netfs);
38}
39
40/*
41 * Unregister NFS for caching
42 */
43void nfs_fscache_unregister(void)
44{
45 fscache_unregister_netfs(&nfs_fscache_netfs);
46}
47
48/*
49 * Define the server object for FS-Cache. This is used to describe a server
50 * object to fscache_acquire_cookie(). It is keyed by the NFS protocol and
51 * server address parameters.
52 */
53const struct fscache_cookie_def nfs_fscache_server_index_def = {
54 .name = "NFS.server",
55 .type = FSCACHE_COOKIE_TYPE_INDEX,
56};
57
58/*
59 * Define the superblock object for FS-Cache. This is used to describe a
60 * superblock object to fscache_acquire_cookie(). It is keyed by all the NFS
61 * parameters that might cause a separate superblock.
62 */
63const struct fscache_cookie_def nfs_fscache_super_index_def = {
64 .name = "NFS.super",
65 .type = FSCACHE_COOKIE_TYPE_INDEX,
66};
67
68/*
69 * Consult the netfs about the state of an object
70 * - This function can be absent if the index carries no state data
71 * - The netfs data from the cookie being used as the target is
72 * presented, as is the auxiliary data
73 */
74static
75enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
76 const void *data,
77 uint16_t datalen,
78 loff_t object_size)
79{
80 struct nfs_fscache_inode_auxdata auxdata;
81 struct nfs_inode *nfsi = cookie_netfs_data;
82
83 if (datalen != sizeof(auxdata))
84 return FSCACHE_CHECKAUX_OBSOLETE;
85
86 memset(&auxdata, 0, sizeof(auxdata));
87 auxdata.mtime = timespec64_to_timespec(nfsi->vfs_inode.i_mtime);
88 auxdata.ctime = timespec64_to_timespec(nfsi->vfs_inode.i_ctime);
89
90 if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
91 auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
92
93 if (memcmp(data, &auxdata, datalen) != 0)
94 return FSCACHE_CHECKAUX_OBSOLETE;
95
96 return FSCACHE_CHECKAUX_OKAY;
97}
98
99/*
100 * Get an extra reference on a read context.
101 * - This function can be absent if the completion function doesn't require a
102 * context.
103 * - The read context is passed back to NFS in the event that a data read on the
104 * cache fails with EIO - in which case the server must be contacted to
105 * retrieve the data, which requires the read context for security.
106 */
107static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
108{
109 get_nfs_open_context(context);
110}
111
112/*
113 * Release an extra reference on a read context.
114 * - This function can be absent if the completion function doesn't require a
115 * context.
116 */
117static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
118{
119 if (context)
120 put_nfs_open_context(context);
121}
122
123/*
124 * Define the inode object for FS-Cache. This is used to describe an inode
125 * object to fscache_acquire_cookie(). It is keyed by the NFS file handle for
126 * an inode.
127 *
128 * Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
129 * held in the cache auxiliary data for the data storage object with those in
130 * the inode struct in memory.
131 */
132const struct fscache_cookie_def nfs_fscache_inode_object_def = {
133 .name = "NFS.fh",
134 .type = FSCACHE_COOKIE_TYPE_DATAFILE,
135 .check_aux = nfs_fscache_inode_check_aux,
136 .get_context = nfs_fh_get_context,
137 .put_context = nfs_fh_put_context,
138};