1 /* 2 * Device operations for the pnfs client. 3 * 4 * Copyright (c) 2002 5 * The Regents of the University of Michigan 6 * All Rights Reserved 7 * 8 * Dean Hildebrand <dhildebz@umich.edu> 9 * Garth Goodson <Garth.Goodson@netapp.com> 10 * 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. 19 * 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. 29 */ 30 31 #include "pnfs.h" 32 33 #define NFSDBG_FACILITY NFSDBG_PNFS 34 35 /* 36 * Device ID RCU cache. A device ID is unique per server and layout type. 37 */ 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) 41 42 static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE]; 43 static DEFINE_SPINLOCK(nfs4_deviceid_lock); 44 45 void 46 nfs4_print_deviceid(const struct nfs4_deviceid *id) 47 { 48 u32 *p = (u32 *)id; 49 50 dprintk("%s: device id= [%x%x%x%x]\n", __func__, 51 p[0], p[1], p[2], p[3]); 52 } 53 EXPORT_SYMBOL_GPL(nfs4_print_deviceid); 54 55 static inline u32 56 nfs4_deviceid_hash(const struct nfs4_deviceid *id) 57 { 58 unsigned char *cptr = (unsigned char *)id->data; 59 unsigned int nbytes = NFS4_DEVICEID4_SIZE; 60 u32 x = 0; 61 62 while (nbytes--) { 63 x *= 37; 64 x += *cptr++; 65 } 66 return x & NFS4_DEVICE_ID_HASH_MASK; 67 } 68 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) 73 { 74 struct nfs4_deviceid_node *d; 75 struct hlist_node *n; 76 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; 84 } 85 return NULL; 86 } 87 88 /* 89 * Lookup a deviceid in cache and get a reference count on it if found 90 * 91 * @clp nfs_client associated with deviceid 92 * @id deviceid to look up 93 */ 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) 98 { 99 struct nfs4_deviceid_node *d; 100 101 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; 107 } 108 109 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) 112 { 113 return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id)); 114 } 115 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid); 116 117 /* 118 * Remove a deviceid from cache 119 * 120 * @clp nfs_client associated with deviceid 121 * @id the deviceid to unhash 122 * 123 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise. 124 */ 125 void 126 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld, 127 const struct nfs_client *clp, const struct nfs4_deviceid *id) 128 { 129 struct nfs4_deviceid_node *d; 130 131 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; 138 } 139 hlist_del_init_rcu(&d->node); 140 spin_unlock(&nfs4_deviceid_lock); 141 synchronize_rcu(); 142 143 /* balance the initial ref set in pnfs_insert_deviceid */ 144 if (atomic_dec_and_test(&d->ref)) 145 d->ld->free_deviceid_node(d); 146 } 147 EXPORT_SYMBOL_GPL(nfs4_delete_deviceid); 148 149 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) 154 { 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); 162 } 163 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node); 164 165 /* 166 * Uniquely initialize and insert a deviceid node into cache 167 * 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 173 * 174 * @ret the inserted node, if none found, otherwise, the found entry. 175 */ 176 struct nfs4_deviceid_node * 177 nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new) 178 { 179 struct nfs4_deviceid_node *d; 180 long hash; 181 182 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; 188 } 189 190 hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]); 191 spin_unlock(&nfs4_deviceid_lock); 192 atomic_inc(&new->ref); 193 194 return new; 195 } 196 EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node); 197 198 /* 199 * Dereference a deviceid node and delete it when its reference count drops 200 * to zero. 201 * 202 * @d deviceid node to put 203 * 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. 207 */ 208 bool 209 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d) 210 { 211 if (!atomic_dec_and_test(&d->ref)) 212 return false; 213 d->ld->free_deviceid_node(d); 214 return true; 215 } 216 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node); 217 218 static void 219 _deviceid_purge_client(const struct nfs_client *clp, long hash) 220 { 221 struct nfs4_deviceid_node *d; 222 struct hlist_node *n; 223 HLIST_HEAD(tmp); 224 225 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); 231 } 232 rcu_read_unlock(); 233 spin_unlock(&nfs4_deviceid_lock); 234 235 if (hlist_empty(&tmp)) 236 return; 237 238 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); 244 } 245 } 246 247 void 248 nfs4_deviceid_purge_client(const struct nfs_client *clp) 249 { 250 long h; 251 252 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); 256 } 257 258 /* 259 * Stop use of all deviceids associated with an nfs_client 260 */ 261 void 262 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp) 263 { 264 struct nfs4_deviceid_node *d; 265 struct hlist_node *n; 266 int i; 267 268 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); 273 } 274 rcu_read_unlock(); 275 } 276