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14727281 DH |
1 | /* NFS filesystem cache interface |
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/seq_file.h> | |
20 | ||
21 | #include "internal.h" | |
22 | #include "fscache.h" | |
23 | ||
24 | #define NFSDBG_FACILITY NFSDBG_FSCACHE | |
25 | ||
08734048 DH |
26 | static struct rb_root nfs_fscache_keys = RB_ROOT; |
27 | static DEFINE_SPINLOCK(nfs_fscache_keys_lock); | |
28 | ||
14727281 DH |
29 | /* |
30 | * Get the per-client index cookie for an NFS client if the appropriate mount | |
31 | * flag was set | |
32 | * - We always try and get an index cookie for the client, but get filehandle | |
33 | * cookies on a per-superblock basis, depending on the mount flags | |
34 | */ | |
35 | void nfs_fscache_get_client_cookie(struct nfs_client *clp) | |
36 | { | |
37 | /* create a cache index for looking up filehandles */ | |
38 | clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index, | |
39 | &nfs_fscache_server_index_def, | |
40 | clp); | |
41 | dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n", | |
42 | clp, clp->fscache); | |
43 | } | |
44 | ||
45 | /* | |
46 | * Dispose of a per-client cookie | |
47 | */ | |
48 | void nfs_fscache_release_client_cookie(struct nfs_client *clp) | |
49 | { | |
50 | dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n", | |
51 | clp, clp->fscache); | |
52 | ||
53 | fscache_relinquish_cookie(clp->fscache, 0); | |
54 | clp->fscache = NULL; | |
55 | } | |
08734048 DH |
56 | |
57 | /* | |
58 | * Get the cache cookie for an NFS superblock. We have to handle | |
59 | * uniquification here because the cache doesn't do it for us. | |
60 | */ | |
61 | void nfs_fscache_get_super_cookie(struct super_block *sb, | |
62 | struct nfs_parsed_mount_data *data) | |
63 | { | |
64 | struct nfs_fscache_key *key, *xkey; | |
65 | struct nfs_server *nfss = NFS_SB(sb); | |
66 | struct rb_node **p, *parent; | |
67 | const char *uniq = data->fscache_uniq ?: ""; | |
68 | int diff, ulen; | |
69 | ||
70 | ulen = strlen(uniq); | |
71 | key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL); | |
72 | if (!key) | |
73 | return; | |
74 | ||
75 | key->nfs_client = nfss->nfs_client; | |
76 | key->key.super.s_flags = sb->s_flags & NFS_MS_MASK; | |
77 | key->key.nfs_server.flags = nfss->flags; | |
78 | key->key.nfs_server.rsize = nfss->rsize; | |
79 | key->key.nfs_server.wsize = nfss->wsize; | |
80 | key->key.nfs_server.acregmin = nfss->acregmin; | |
81 | key->key.nfs_server.acregmax = nfss->acregmax; | |
82 | key->key.nfs_server.acdirmin = nfss->acdirmin; | |
83 | key->key.nfs_server.acdirmax = nfss->acdirmax; | |
84 | key->key.nfs_server.fsid = nfss->fsid; | |
85 | key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor; | |
86 | ||
87 | key->key.uniq_len = ulen; | |
88 | memcpy(key->key.uniquifier, uniq, ulen); | |
89 | ||
90 | spin_lock(&nfs_fscache_keys_lock); | |
91 | p = &nfs_fscache_keys.rb_node; | |
92 | parent = NULL; | |
93 | while (*p) { | |
94 | parent = *p; | |
95 | xkey = rb_entry(parent, struct nfs_fscache_key, node); | |
96 | ||
97 | if (key->nfs_client < xkey->nfs_client) | |
98 | goto go_left; | |
99 | if (key->nfs_client > xkey->nfs_client) | |
100 | goto go_right; | |
101 | ||
102 | diff = memcmp(&key->key, &xkey->key, sizeof(key->key)); | |
103 | if (diff < 0) | |
104 | goto go_left; | |
105 | if (diff > 0) | |
106 | goto go_right; | |
107 | ||
108 | if (key->key.uniq_len == 0) | |
109 | goto non_unique; | |
110 | diff = memcmp(key->key.uniquifier, | |
111 | xkey->key.uniquifier, | |
112 | key->key.uniq_len); | |
113 | if (diff < 0) | |
114 | goto go_left; | |
115 | if (diff > 0) | |
116 | goto go_right; | |
117 | goto non_unique; | |
118 | ||
119 | go_left: | |
120 | p = &(*p)->rb_left; | |
121 | continue; | |
122 | go_right: | |
123 | p = &(*p)->rb_right; | |
124 | } | |
125 | ||
126 | rb_link_node(&key->node, parent, p); | |
127 | rb_insert_color(&key->node, &nfs_fscache_keys); | |
128 | spin_unlock(&nfs_fscache_keys_lock); | |
129 | nfss->fscache_key = key; | |
130 | ||
131 | /* create a cache index for looking up filehandles */ | |
132 | nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache, | |
133 | &nfs_fscache_super_index_def, | |
134 | nfss); | |
135 | dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n", | |
136 | nfss, nfss->fscache); | |
137 | return; | |
138 | ||
139 | non_unique: | |
140 | spin_unlock(&nfs_fscache_keys_lock); | |
141 | kfree(key); | |
142 | nfss->fscache_key = NULL; | |
143 | nfss->fscache = NULL; | |
144 | printk(KERN_WARNING "NFS:" | |
145 | " Cache request denied due to non-unique superblock keys\n"); | |
146 | } | |
147 | ||
148 | /* | |
149 | * release a per-superblock cookie | |
150 | */ | |
151 | void nfs_fscache_release_super_cookie(struct super_block *sb) | |
152 | { | |
153 | struct nfs_server *nfss = NFS_SB(sb); | |
154 | ||
155 | dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n", | |
156 | nfss, nfss->fscache); | |
157 | ||
158 | fscache_relinquish_cookie(nfss->fscache, 0); | |
159 | nfss->fscache = NULL; | |
160 | ||
161 | if (nfss->fscache_key) { | |
162 | spin_lock(&nfs_fscache_keys_lock); | |
163 | rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys); | |
164 | spin_unlock(&nfs_fscache_keys_lock); | |
165 | kfree(nfss->fscache_key); | |
166 | nfss->fscache_key = NULL; | |
167 | } | |
168 | } |