nfs41: implement DESTROY_CLIENTID operation
[linux-btrfs-devel.git] / fs / nfs / pnfs_dev.c
blob6fda5228ef5627d45da3cdf4933e6a098b018820
1 /*
2 * Device operations for the pnfs client.
4 * Copyright (c) 2002
5 * The Regents of the University of Michigan
6 * All Rights Reserved
8 * Dean Hildebrand <dhildebz@umich.edu>
9 * Garth Goodson <Garth.Goodson@netapp.com>
11 * Permission is granted to use, copy, create derivative works, and
12 * redistribute this software and such derivative works for any purpose,
13 * so long as the name of the University of Michigan is not used in
14 * any advertising or publicity pertaining to the use or distribution
15 * of this software without specific, written prior authorization. If
16 * the above copyright notice or any other identification of the
17 * University of Michigan is included in any copy of any portion of
18 * this software, then the disclaimer below must also be included.
20 * This software is provided as is, without representation or warranty
21 * of any kind either express or implied, including without limitation
22 * the implied warranties of merchantability, fitness for a particular
23 * purpose, or noninfringement. The Regents of the University of
24 * Michigan shall not be liable for any damages, including special,
25 * indirect, incidental, or consequential damages, with respect to any
26 * claim arising out of or in connection with the use of the software,
27 * even if it has been or is hereafter advised of the possibility of
28 * such damages.
31 #include "pnfs.h"
33 #define NFSDBG_FACILITY NFSDBG_PNFS
36 * Device ID RCU cache. A device ID is unique per server and layout type.
38 #define NFS4_DEVICE_ID_HASH_BITS 5
39 #define NFS4_DEVICE_ID_HASH_SIZE (1 << NFS4_DEVICE_ID_HASH_BITS)
40 #define NFS4_DEVICE_ID_HASH_MASK (NFS4_DEVICE_ID_HASH_SIZE - 1)
42 static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
43 static DEFINE_SPINLOCK(nfs4_deviceid_lock);
45 void
46 nfs4_print_deviceid(const struct nfs4_deviceid *id)
48 u32 *p = (u32 *)id;
50 dprintk("%s: device id= [%x%x%x%x]\n", __func__,
51 p[0], p[1], p[2], p[3]);
53 EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
55 static inline u32
56 nfs4_deviceid_hash(const struct nfs4_deviceid *id)
58 unsigned char *cptr = (unsigned char *)id->data;
59 unsigned int nbytes = NFS4_DEVICEID4_SIZE;
60 u32 x = 0;
62 while (nbytes--) {
63 x *= 37;
64 x += *cptr++;
66 return x & NFS4_DEVICE_ID_HASH_MASK;
69 static struct nfs4_deviceid_node *
70 _lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
71 const struct nfs_client *clp, const struct nfs4_deviceid *id,
72 long hash)
74 struct nfs4_deviceid_node *d;
75 struct hlist_node *n;
77 hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
78 if (d->ld == ld && d->nfs_client == clp &&
79 !memcmp(&d->deviceid, id, sizeof(*id))) {
80 if (atomic_read(&d->ref))
81 return d;
82 else
83 continue;
85 return NULL;
89 * Lookup a deviceid in cache and get a reference count on it if found
91 * @clp nfs_client associated with deviceid
92 * @id deviceid to look up
94 struct nfs4_deviceid_node *
95 _find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
96 const struct nfs_client *clp, const struct nfs4_deviceid *id,
97 long hash)
99 struct nfs4_deviceid_node *d;
101 rcu_read_lock();
102 d = _lookup_deviceid(ld, clp, id, hash);
103 if (d != NULL)
104 atomic_inc(&d->ref);
105 rcu_read_unlock();
106 return d;
109 struct nfs4_deviceid_node *
110 nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
111 const struct nfs_client *clp, const struct nfs4_deviceid *id)
113 return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
115 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
118 * Remove a deviceid from cache
120 * @clp nfs_client associated with deviceid
121 * @id the deviceid to unhash
123 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
125 void
126 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
127 const struct nfs_client *clp, const struct nfs4_deviceid *id)
129 struct nfs4_deviceid_node *d;
131 spin_lock(&nfs4_deviceid_lock);
132 rcu_read_lock();
133 d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
134 rcu_read_unlock();
135 if (!d) {
136 spin_unlock(&nfs4_deviceid_lock);
137 return;
139 hlist_del_init_rcu(&d->node);
140 spin_unlock(&nfs4_deviceid_lock);
141 synchronize_rcu();
143 /* balance the initial ref set in pnfs_insert_deviceid */
144 if (atomic_dec_and_test(&d->ref))
145 d->ld->free_deviceid_node(d);
147 EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
149 void
150 nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
151 const struct pnfs_layoutdriver_type *ld,
152 const struct nfs_client *nfs_client,
153 const struct nfs4_deviceid *id)
155 INIT_HLIST_NODE(&d->node);
156 INIT_HLIST_NODE(&d->tmpnode);
157 d->ld = ld;
158 d->nfs_client = nfs_client;
159 d->flags = 0;
160 d->deviceid = *id;
161 atomic_set(&d->ref, 1);
163 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
166 * Uniquely initialize and insert a deviceid node into cache
168 * @new new deviceid node
169 * Note that the caller must set up the following members:
170 * new->ld
171 * new->nfs_client
172 * new->deviceid
174 * @ret the inserted node, if none found, otherwise, the found entry.
176 struct nfs4_deviceid_node *
177 nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
179 struct nfs4_deviceid_node *d;
180 long hash;
182 spin_lock(&nfs4_deviceid_lock);
183 hash = nfs4_deviceid_hash(&new->deviceid);
184 d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash);
185 if (d) {
186 spin_unlock(&nfs4_deviceid_lock);
187 return d;
190 hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
191 spin_unlock(&nfs4_deviceid_lock);
192 atomic_inc(&new->ref);
194 return new;
196 EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node);
199 * Dereference a deviceid node and delete it when its reference count drops
200 * to zero.
202 * @d deviceid node to put
204 * return true iff the node was deleted
205 * Note that since the test for d->ref == 0 is sufficient to establish
206 * that the node is no longer hashed in the global device id cache.
208 bool
209 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
211 if (!atomic_dec_and_test(&d->ref))
212 return false;
213 d->ld->free_deviceid_node(d);
214 return true;
216 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
218 static void
219 _deviceid_purge_client(const struct nfs_client *clp, long hash)
221 struct nfs4_deviceid_node *d;
222 struct hlist_node *n;
223 HLIST_HEAD(tmp);
225 spin_lock(&nfs4_deviceid_lock);
226 rcu_read_lock();
227 hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node)
228 if (d->nfs_client == clp && atomic_read(&d->ref)) {
229 hlist_del_init_rcu(&d->node);
230 hlist_add_head(&d->tmpnode, &tmp);
232 rcu_read_unlock();
233 spin_unlock(&nfs4_deviceid_lock);
235 if (hlist_empty(&tmp))
236 return;
238 synchronize_rcu();
239 while (!hlist_empty(&tmp)) {
240 d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
241 hlist_del(&d->tmpnode);
242 if (atomic_dec_and_test(&d->ref))
243 d->ld->free_deviceid_node(d);
247 void
248 nfs4_deviceid_purge_client(const struct nfs_client *clp)
250 long h;
252 if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
253 return;
254 for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
255 _deviceid_purge_client(clp, h);
259 * Stop use of all deviceids associated with an nfs_client
261 void
262 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
264 struct nfs4_deviceid_node *d;
265 struct hlist_node *n;
266 int i;
268 rcu_read_lock();
269 for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
270 hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[i], node)
271 if (d->nfs_client == clp)
272 set_bit(NFS_DEVICEID_INVALID, &d->flags);
274 rcu_read_unlock();