xref: /kernel/linux/linux-5.10/fs/nfs/fscache-index.c (revision 8c2ecf20) 
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_sec  = nfsi->vfs_inode.i_mtime.tv_sec;
88	auxdata.mtime_nsec = nfsi->vfs_inode.i_mtime.tv_nsec;
89	auxdata.ctime_sec  = nfsi->vfs_inode.i_ctime.tv_sec;
90	auxdata.ctime_nsec = nfsi->vfs_inode.i_ctime.tv_nsec;
91
92	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
93		auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
94
95	if (memcmp(data, &auxdata, datalen) != 0)
96		return FSCACHE_CHECKAUX_OBSOLETE;
97
98	return FSCACHE_CHECKAUX_OKAY;
99}
100
101/*
102 * Get an extra reference on a read context.
103 * - This function can be absent if the completion function doesn't require a
104 *   context.
105 * - The read context is passed back to NFS in the event that a data read on the
106 *   cache fails with EIO - in which case the server must be contacted to
107 *   retrieve the data, which requires the read context for security.
108 */
109static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
110{
111	get_nfs_open_context(context);
112}
113
114/*
115 * Release an extra reference on a read context.
116 * - This function can be absent if the completion function doesn't require a
117 *   context.
118 */
119static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
120{
121	if (context)
122		put_nfs_open_context(context);
123}
124
125/*
126 * Define the inode object for FS-Cache.  This is used to describe an inode
127 * object to fscache_acquire_cookie().  It is keyed by the NFS file handle for
128 * an inode.
129 *
130 * Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
131 * held in the cache auxiliary data for the data storage object with those in
132 * the inode struct in memory.
133 */
134const struct fscache_cookie_def nfs_fscache_inode_object_def = {
135	.name		= "NFS.fh",
136	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
137	.check_aux	= nfs_fscache_inode_check_aux,
138	.get_context	= nfs_fh_get_context,
139	.put_context	= nfs_fh_put_context,
140};
141