1 /* NFS FS-Cache index structure definition
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/iversion.h>
20
21 #include "internal.h"
22 #include "fscache.h"
23
24 #define NFSDBG_FACILITY NFSDBG_FSCACHE
25
26 /*
27 * Define the NFS filesystem for FS-Cache. Upon registration FS-Cache sticks
28 * the cookie for the top-level index object for NFS into here. The top-level
29 * index can than have other cache objects inserted into it.
30 */
31 struct fscache_netfs nfs_fscache_netfs = {
32 .name = "nfs",
33 .version = 0,
34 };
35
36 /*
37 * Register NFS for caching
38 */
nfs_fscache_register(void)39 int nfs_fscache_register(void)
40 {
41 return fscache_register_netfs(&nfs_fscache_netfs);
42 }
43
44 /*
45 * Unregister NFS for caching
46 */
nfs_fscache_unregister(void)47 void nfs_fscache_unregister(void)
48 {
49 fscache_unregister_netfs(&nfs_fscache_netfs);
50 }
51
52 /*
53 * Define the server object for FS-Cache. This is used to describe a server
54 * object to fscache_acquire_cookie(). It is keyed by the NFS protocol and
55 * server address parameters.
56 */
57 const struct fscache_cookie_def nfs_fscache_server_index_def = {
58 .name = "NFS.server",
59 .type = FSCACHE_COOKIE_TYPE_INDEX,
60 };
61
62 /*
63 * Define the superblock object for FS-Cache. This is used to describe a
64 * superblock object to fscache_acquire_cookie(). It is keyed by all the NFS
65 * parameters that might cause a separate superblock.
66 */
67 const struct fscache_cookie_def nfs_fscache_super_index_def = {
68 .name = "NFS.super",
69 .type = FSCACHE_COOKIE_TYPE_INDEX,
70 };
71
72 /*
73 * Consult the netfs about the state of an object
74 * - This function can be absent if the index carries no state data
75 * - The netfs data from the cookie being used as the target is
76 * presented, as is the auxiliary data
77 */
78 static
nfs_fscache_inode_check_aux(void * cookie_netfs_data,const void * data,uint16_t datalen,loff_t object_size)79 enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
80 const void *data,
81 uint16_t datalen,
82 loff_t object_size)
83 {
84 struct nfs_fscache_inode_auxdata auxdata;
85 struct nfs_inode *nfsi = cookie_netfs_data;
86
87 if (datalen != sizeof(auxdata))
88 return FSCACHE_CHECKAUX_OBSOLETE;
89
90 memset(&auxdata, 0, sizeof(auxdata));
91 auxdata.mtime = timespec64_to_timespec(nfsi->vfs_inode.i_mtime);
92 auxdata.ctime = timespec64_to_timespec(nfsi->vfs_inode.i_ctime);
93
94 if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
95 auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
96
97 if (memcmp(data, &auxdata, datalen) != 0)
98 return FSCACHE_CHECKAUX_OBSOLETE;
99
100 return FSCACHE_CHECKAUX_OKAY;
101 }
102
103 /*
104 * Get an extra reference on a read context.
105 * - This function can be absent if the completion function doesn't require a
106 * context.
107 * - The read context is passed back to NFS in the event that a data read on the
108 * cache fails with EIO - in which case the server must be contacted to
109 * retrieve the data, which requires the read context for security.
110 */
nfs_fh_get_context(void * cookie_netfs_data,void * context)111 static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
112 {
113 get_nfs_open_context(context);
114 }
115
116 /*
117 * Release an extra reference on a read context.
118 * - This function can be absent if the completion function doesn't require a
119 * context.
120 */
nfs_fh_put_context(void * cookie_netfs_data,void * context)121 static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
122 {
123 if (context)
124 put_nfs_open_context(context);
125 }
126
127 /*
128 * Define the inode object for FS-Cache. This is used to describe an inode
129 * object to fscache_acquire_cookie(). It is keyed by the NFS file handle for
130 * an inode.
131 *
132 * Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
133 * held in the cache auxiliary data for the data storage object with those in
134 * the inode struct in memory.
135 */
136 const struct fscache_cookie_def nfs_fscache_inode_object_def = {
137 .name = "NFS.fh",
138 .type = FSCACHE_COOKIE_TYPE_DATAFILE,
139 .check_aux = nfs_fscache_inode_check_aux,
140 .get_context = nfs_fh_get_context,
141 .put_context = nfs_fh_put_context,
142 };
143
