2 * Device operations for the pnfs client.
5 * The Regents of the University of Michigan
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
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);
46 nfs4_print_deviceid(const struct nfs4_deviceid *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);
56 nfs4_deviceid_hash(const struct nfs4_deviceid *id)
58 unsigned char *cptr = (unsigned char *)id->data;
59 unsigned int nbytes = NFS4_DEVICEID4_SIZE;
66 return x & NFS4_DEVICE_ID_HASH_MASK;
70 * Lookup a deviceid in cache and get a reference count on it if found
72 * @clp nfs_client associated with deviceid
73 * @id deviceid to look up
75 struct nfs4_deviceid_node *
76 nfs4_find_get_deviceid(const struct nfs_client *clp, const struct nfs4_deviceid *id)
78 struct nfs4_deviceid_node *d;
80 long hash = nfs4_deviceid_hash(id);
83 hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node) {
84 if (d->nfs_client == clp && !memcmp(&d->deviceid, id, sizeof(*id))) {
85 if (!atomic_inc_not_zero(&d->ref))
95 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
98 nfs4_init_deviceid_node(struct nfs4_deviceid_node *d,
99 const struct nfs_client *nfs_client,
100 const struct nfs4_deviceid *id)
102 d->nfs_client = nfs_client;
105 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
108 * Uniquely initialize and insert a deviceid node into cache
110 * @new new deviceid node
111 * Note that the caller must set up new->nfs_client and new->deviceid
113 * @ret the inserted node, if none found, otherwise, the found entry.
115 struct nfs4_deviceid_node *
116 nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new)
118 struct nfs4_deviceid_node *d;
121 spin_lock(&nfs4_deviceid_lock);
122 d = nfs4_find_get_deviceid(new->nfs_client, &new->deviceid);
124 spin_unlock(&nfs4_deviceid_lock);
128 INIT_HLIST_NODE(&new->node);
129 atomic_set(&new->ref, 1);
130 hash = nfs4_deviceid_hash(&new->deviceid);
131 hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
132 spin_unlock(&nfs4_deviceid_lock);
136 EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node);
139 * Dereference a deviceid node and delete it when its reference count drops
142 * @d deviceid node to put
144 * @ret true iff the node was deleted
147 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
149 if (!atomic_dec_and_lock(&d->ref, &nfs4_deviceid_lock))
151 hlist_del_init_rcu(&d->node);
152 spin_unlock(&nfs4_deviceid_lock);
156 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);