xref: /kernel/linux/linux-5.10/fs/cifs/cache.c (revision 8c2ecf20)
1/*
2 *   fs/cifs/cache.c - CIFS filesystem cache index structure definitions
3 *
4 *   Copyright (c) 2010 Novell, Inc.
5 *   Authors(s): Suresh Jayaraman (sjayaraman@suse.de>
6 *
7 *   This library is free software; you can redistribute it and/or modify
8 *   it under the terms of the GNU Lesser General Public License as published
9 *   by the Free Software Foundation; either version 2.1 of the License, or
10 *   (at your option) any later version.
11 *
12 *   This library is distributed in the hope that it will be useful,
13 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
15 *   the GNU Lesser General Public License for more details.
16 *
17 *   You should have received a copy of the GNU Lesser General Public License
18 *   along with this library; if not, write to the Free Software
19 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21#include "fscache.h"
22#include "cifs_debug.h"
23
24/*
25 * CIFS filesystem definition for FS-Cache
26 */
27struct fscache_netfs cifs_fscache_netfs = {
28	.name = "cifs",
29	.version = 0,
30};
31
32/*
33 * Register CIFS for caching with FS-Cache
34 */
35int cifs_fscache_register(void)
36{
37	return fscache_register_netfs(&cifs_fscache_netfs);
38}
39
40/*
41 * Unregister CIFS for caching
42 */
43void cifs_fscache_unregister(void)
44{
45	fscache_unregister_netfs(&cifs_fscache_netfs);
46}
47
48/*
49 * Server object for FS-Cache
50 */
51const struct fscache_cookie_def cifs_fscache_server_index_def = {
52	.name = "CIFS.server",
53	.type = FSCACHE_COOKIE_TYPE_INDEX,
54};
55
56char *extract_sharename(const char *treename)
57{
58	const char *src;
59	char *delim, *dst;
60	int len;
61
62	/* skip double chars at the beginning */
63	src = treename + 2;
64
65	/* share name is always preceded by '\\' now */
66	delim = strchr(src, '\\');
67	if (!delim)
68		return ERR_PTR(-EINVAL);
69	delim++;
70	len = strlen(delim);
71
72	/* caller has to free the memory */
73	dst = kstrndup(delim, len, GFP_KERNEL);
74	if (!dst)
75		return ERR_PTR(-ENOMEM);
76
77	return dst;
78}
79
80static enum
81fscache_checkaux cifs_fscache_super_check_aux(void *cookie_netfs_data,
82					      const void *data,
83					      uint16_t datalen,
84					      loff_t object_size)
85{
86	struct cifs_fscache_super_auxdata auxdata;
87	const struct cifs_tcon *tcon = cookie_netfs_data;
88
89	if (datalen != sizeof(auxdata))
90		return FSCACHE_CHECKAUX_OBSOLETE;
91
92	memset(&auxdata, 0, sizeof(auxdata));
93	auxdata.resource_id = tcon->resource_id;
94	auxdata.vol_create_time = tcon->vol_create_time;
95	auxdata.vol_serial_number = tcon->vol_serial_number;
96
97	if (memcmp(data, &auxdata, datalen) != 0)
98		return FSCACHE_CHECKAUX_OBSOLETE;
99
100	return FSCACHE_CHECKAUX_OKAY;
101}
102
103/*
104 * Superblock object for FS-Cache
105 */
106const struct fscache_cookie_def cifs_fscache_super_index_def = {
107	.name = "CIFS.super",
108	.type = FSCACHE_COOKIE_TYPE_INDEX,
109	.check_aux = cifs_fscache_super_check_aux,
110};
111
112static enum
113fscache_checkaux cifs_fscache_inode_check_aux(void *cookie_netfs_data,
114					      const void *data,
115					      uint16_t datalen,
116					      loff_t object_size)
117{
118	struct cifs_fscache_inode_auxdata auxdata;
119	struct cifsInodeInfo *cifsi = cookie_netfs_data;
120
121	if (datalen != sizeof(auxdata))
122		return FSCACHE_CHECKAUX_OBSOLETE;
123
124	memset(&auxdata, 0, sizeof(auxdata));
125	auxdata.eof = cifsi->server_eof;
126	auxdata.last_write_time_sec = cifsi->vfs_inode.i_mtime.tv_sec;
127	auxdata.last_change_time_sec = cifsi->vfs_inode.i_ctime.tv_sec;
128	auxdata.last_write_time_nsec = cifsi->vfs_inode.i_mtime.tv_nsec;
129	auxdata.last_change_time_nsec = cifsi->vfs_inode.i_ctime.tv_nsec;
130
131	if (memcmp(data, &auxdata, datalen) != 0)
132		return FSCACHE_CHECKAUX_OBSOLETE;
133
134	return FSCACHE_CHECKAUX_OKAY;
135}
136
137const struct fscache_cookie_def cifs_fscache_inode_object_def = {
138	.name		= "CIFS.uniqueid",
139	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
140	.check_aux	= cifs_fscache_inode_check_aux,
141};
142