1 /* NFS filesystem cache interface
3 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.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>
24 #define NFSDBG_FACILITY NFSDBG_FSCACHE
26 static struct rb_root nfs_fscache_keys = RB_ROOT;
27 static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
30 * Get the per-client index cookie for an NFS client if the appropriate mount
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
35 void nfs_fscache_get_client_cookie(struct nfs_client *clp)
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,
41 dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
46 * Dispose of a per-client cookie
48 void nfs_fscache_release_client_cookie(struct nfs_client *clp)
50 dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
53 fscache_relinquish_cookie(clp->fscache, 0);
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.
61 void nfs_fscache_get_super_cookie(struct super_block *sb,
62 struct nfs_parsed_mount_data *data)
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 ?: "";
71 key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
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;
87 key->key.uniq_len = ulen;
88 memcpy(key->key.uniquifier, uniq, ulen);
90 spin_lock(&nfs_fscache_keys_lock);
91 p = &nfs_fscache_keys.rb_node;
95 xkey = rb_entry(parent, struct nfs_fscache_key, node);
97 if (key->nfs_client < xkey->nfs_client)
99 if (key->nfs_client > xkey->nfs_client)
102 diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
108 if (key->key.uniq_len == 0)
110 diff = memcmp(key->key.uniquifier,
111 xkey->key.uniquifier,
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;
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,
135 dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
136 nfss, nfss->fscache);
140 spin_unlock(&nfs_fscache_keys_lock);
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");
149 * release a per-superblock cookie
151 void nfs_fscache_release_super_cookie(struct super_block *sb)
153 struct nfs_server *nfss = NFS_SB(sb);
155 dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
156 nfss, nfss->fscache);
158 fscache_relinquish_cookie(nfss->fscache, 0);
159 nfss->fscache = NULL;
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;
171 * Initialise the per-inode cache cookie pointer for an NFS inode.
173 void nfs_fscache_init_inode_cookie(struct inode *inode)
175 NFS_I(inode)->fscache = NULL;
176 if (S_ISREG(inode->i_mode))
177 set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
181 * Get the per-inode cache cookie for an NFS inode.
183 static void nfs_fscache_enable_inode_cookie(struct inode *inode)
185 struct super_block *sb = inode->i_sb;
186 struct nfs_inode *nfsi = NFS_I(inode);
188 if (nfsi->fscache || !NFS_FSCACHE(inode))
191 if ((NFS_SB(sb)->options & NFS_OPTION_FSCACHE)) {
192 nfsi->fscache = fscache_acquire_cookie(
194 &nfs_fscache_inode_object_def,
197 dfprintk(FSCACHE, "NFS: get FH cookie (0x%p/0x%p/0x%p)\n",
198 sb, nfsi, nfsi->fscache);
203 * Release a per-inode cookie.
205 void nfs_fscache_release_inode_cookie(struct inode *inode)
207 struct nfs_inode *nfsi = NFS_I(inode);
209 dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n",
210 nfsi, nfsi->fscache);
212 fscache_relinquish_cookie(nfsi->fscache, 0);
213 nfsi->fscache = NULL;
217 * Retire a per-inode cookie, destroying the data attached to it.
219 void nfs_fscache_zap_inode_cookie(struct inode *inode)
221 struct nfs_inode *nfsi = NFS_I(inode);
223 dfprintk(FSCACHE, "NFS: zapping cookie (0x%p/0x%p)\n",
224 nfsi, nfsi->fscache);
226 fscache_relinquish_cookie(nfsi->fscache, 1);
227 nfsi->fscache = NULL;
231 * Turn off the cache with regard to a per-inode cookie if opened for writing,
232 * invalidating all the pages in the page cache relating to the associated
233 * inode to clear the per-page caching.
235 static void nfs_fscache_disable_inode_cookie(struct inode *inode)
237 clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
239 if (NFS_I(inode)->fscache) {
241 "NFS: nfsi 0x%p turning cache off\n", NFS_I(inode));
243 /* Need to invalidate any mapped pages that were read in before
244 * turning off the cache.
246 if (inode->i_mapping && inode->i_mapping->nrpages)
247 invalidate_inode_pages2(inode->i_mapping);
249 nfs_fscache_zap_inode_cookie(inode);
254 * wait_on_bit() sleep function for uninterruptible waiting
256 static int nfs_fscache_wait_bit(void *flags)
263 * Lock against someone else trying to also acquire or relinquish a cookie
265 static inline void nfs_fscache_inode_lock(struct inode *inode)
267 struct nfs_inode *nfsi = NFS_I(inode);
269 while (test_and_set_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags))
270 wait_on_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK,
271 nfs_fscache_wait_bit, TASK_UNINTERRUPTIBLE);
275 * Unlock cookie management lock
277 static inline void nfs_fscache_inode_unlock(struct inode *inode)
279 struct nfs_inode *nfsi = NFS_I(inode);
281 smp_mb__before_clear_bit();
282 clear_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags);
283 smp_mb__after_clear_bit();
284 wake_up_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK);
288 * Decide if we should enable or disable local caching for this inode.
289 * - For now, with NFS, only regular files that are open read-only will be able
291 * - May be invoked multiple times in parallel by parallel nfs_open() functions.
293 void nfs_fscache_set_inode_cookie(struct inode *inode, struct file *filp)
295 if (NFS_FSCACHE(inode)) {
296 nfs_fscache_inode_lock(inode);
297 if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
298 nfs_fscache_disable_inode_cookie(inode);
300 nfs_fscache_enable_inode_cookie(inode);
301 nfs_fscache_inode_unlock(inode);
306 * Replace a per-inode cookie due to revalidation detecting a file having
307 * changed on the server.
309 void nfs_fscache_reset_inode_cookie(struct inode *inode)
311 struct nfs_inode *nfsi = NFS_I(inode);
312 struct nfs_server *nfss = NFS_SERVER(inode);
313 struct fscache_cookie *old = nfsi->fscache;
315 nfs_fscache_inode_lock(inode);
317 /* retire the current fscache cache and get a new one */
318 fscache_relinquish_cookie(nfsi->fscache, 1);
320 nfsi->fscache = fscache_acquire_cookie(
321 nfss->nfs_client->fscache,
322 &nfs_fscache_inode_object_def,
326 "NFS: revalidation new cookie (0x%p/0x%p/0x%p/0x%p)\n",
327 nfss, nfsi, old, nfsi->fscache);
329 nfs_fscache_inode_unlock(inode);