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 <linux/export.h> 32 #include "pnfs.h" 33 34 #define NFSDBG_FACILITY NFSDBG_PNFS 35 36 /* 37 * Device ID RCU cache. A device ID is unique per server and layout type. 38 */ 39 #define NFS4_DEVICE_ID_HASH_BITS 5 40 #define NFS4_DEVICE_ID_HASH_SIZE (1 << NFS4_DEVICE_ID_HASH_BITS) 41 #define NFS4_DEVICE_ID_HASH_MASK (NFS4_DEVICE_ID_HASH_SIZE - 1) 42 43 static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE]; 44 static DEFINE_SPINLOCK(nfs4_deviceid_lock); 45 46 #ifdef NFS_DEBUG 47 void 48 nfs4_print_deviceid(const struct nfs4_deviceid *id) 49 { 50 u32 *p = (u32 *)id; 51 52 dprintk("%s: device id= [%x%x%x%x]\n", __func__, 53 p[0], p[1], p[2], p[3]); 54 } 55 EXPORT_SYMBOL_GPL(nfs4_print_deviceid); 56 #endif 57 58 static inline u32 59 nfs4_deviceid_hash(const struct nfs4_deviceid *id) 60 { 61 unsigned char *cptr = (unsigned char *)id->data; 62 unsigned int nbytes = NFS4_DEVICEID4_SIZE; 63 u32 x = 0; 64 65 while (nbytes--) { 66 x *= 37; 67 x += *cptr++; 68 } 69 return x & NFS4_DEVICE_ID_HASH_MASK; 70 } 71 72 static struct nfs4_deviceid_node * 73 _lookup_deviceid(const struct pnfs_layoutdriver_type *ld, 74 const struct nfs_client *clp, const struct nfs4_deviceid *id, 75 long hash) 76 { 77 struct nfs4_deviceid_node *d; 78 struct hlist_node *n; 79 80 hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node) 81 if (d->ld == ld && d->nfs_client == clp && 82 !memcmp(&d->deviceid, id, sizeof(*id))) { 83 if (atomic_read(&d->ref)) 84 return d; 85 else 86 continue; 87 } 88 return NULL; 89 } 90 91 /* 92 * Lookup a deviceid in cache and get a reference count on it if found 93 * 94 * @clp nfs_client associated with deviceid 95 * @id deviceid to look up 96 */ 97 static struct nfs4_deviceid_node * 98 _find_get_deviceid(const struct pnfs_layoutdriver_type *ld, 99 const struct nfs_client *clp, const struct nfs4_deviceid *id, 100 long hash) 101 { 102 struct nfs4_deviceid_node *d; 103 104 rcu_read_lock(); 105 d = _lookup_deviceid(ld, clp, id, hash); 106 if (d != NULL) 107 atomic_inc(&d->ref); 108 rcu_read_unlock(); 109 return d; 110 } 111 112 struct nfs4_deviceid_node * 113 nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld, 114 const struct nfs_client *clp, const struct nfs4_deviceid *id) 115 { 116 return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id)); 117 } 118 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid); 119 120 /* 121 * Remove a deviceid from cache 122 * 123 * @clp nfs_client associated with deviceid 124 * @id the deviceid to unhash 125 * 126 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise. 127 */ 128 void 129 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld, 130 const struct nfs_client *clp, const struct nfs4_deviceid *id) 131 { 132 struct nfs4_deviceid_node *d; 133 134 spin_lock(&nfs4_deviceid_lock); 135 rcu_read_lock(); 136 d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id)); 137 rcu_read_unlock(); 138 if (!d) { 139 spin_unlock(&nfs4_deviceid_lock); 140 return; 141 } 142 hlist_del_init_rcu(&d->node); 143 spin_unlock(&nfs4_deviceid_lock); 144 synchronize_rcu(); 145 146 /* balance the initial ref set in pnfs_insert_deviceid */ 147 if (atomic_dec_and_test(&d->ref)) 148 d->ld->free_deviceid_node(d); 149 } 150 EXPORT_SYMBOL_GPL(nfs4_delete_deviceid); 151 152 void 153 nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, 154 const struct pnfs_layoutdriver_type *ld, 155 const struct nfs_client *nfs_client, 156 const struct nfs4_deviceid *id) 157 { 158 INIT_HLIST_NODE(&d->node); 159 INIT_HLIST_NODE(&d->tmpnode); 160 d->ld = ld; 161 d->nfs_client = nfs_client; 162 d->flags = 0; 163 d->deviceid = *id; 164 atomic_set(&d->ref, 1); 165 } 166 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node); 167 168 /* 169 * Uniquely initialize and insert a deviceid node into cache 170 * 171 * @new new deviceid node 172 * Note that the caller must set up the following members: 173 * new->ld 174 * new->nfs_client 175 * new->deviceid 176 * 177 * @ret the inserted node, if none found, otherwise, the found entry. 178 */ 179 struct nfs4_deviceid_node * 180 nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new) 181 { 182 struct nfs4_deviceid_node *d; 183 long hash; 184 185 spin_lock(&nfs4_deviceid_lock); 186 hash = nfs4_deviceid_hash(&new->deviceid); 187 d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash); 188 if (d) { 189 spin_unlock(&nfs4_deviceid_lock); 190 return d; 191 } 192 193 hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]); 194 spin_unlock(&nfs4_deviceid_lock); 195 atomic_inc(&new->ref); 196 197 return new; 198 } 199 EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node); 200 201 /* 202 * Dereference a deviceid node and delete it when its reference count drops 203 * to zero. 204 * 205 * @d deviceid node to put 206 * 207 * return true iff the node was deleted 208 * Note that since the test for d->ref == 0 is sufficient to establish 209 * that the node is no longer hashed in the global device id cache. 210 */ 211 bool 212 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d) 213 { 214 if (!atomic_dec_and_test(&d->ref)) 215 return false; 216 d->ld->free_deviceid_node(d); 217 return true; 218 } 219 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node); 220 221 static void 222 _deviceid_purge_client(const struct nfs_client *clp, long hash) 223 { 224 struct nfs4_deviceid_node *d; 225 struct hlist_node *n; 226 HLIST_HEAD(tmp); 227 228 spin_lock(&nfs4_deviceid_lock); 229 rcu_read_lock(); 230 hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node) 231 if (d->nfs_client == clp && atomic_read(&d->ref)) { 232 hlist_del_init_rcu(&d->node); 233 hlist_add_head(&d->tmpnode, &tmp); 234 } 235 rcu_read_unlock(); 236 spin_unlock(&nfs4_deviceid_lock); 237 238 if (hlist_empty(&tmp)) 239 return; 240 241 synchronize_rcu(); 242 while (!hlist_empty(&tmp)) { 243 d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode); 244 hlist_del(&d->tmpnode); 245 if (atomic_dec_and_test(&d->ref)) 246 d->ld->free_deviceid_node(d); 247 } 248 } 249 250 void 251 nfs4_deviceid_purge_client(const struct nfs_client *clp) 252 { 253 long h; 254 255 if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS)) 256 return; 257 for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++) 258 _deviceid_purge_client(clp, h); 259 } 260 261 /* 262 * Stop use of all deviceids associated with an nfs_client 263 */ 264 void 265 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp) 266 { 267 struct nfs4_deviceid_node *d; 268 struct hlist_node *n; 269 int i; 270 271 rcu_read_lock(); 272 for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){ 273 hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[i], node) 274 if (d->nfs_client == clp) 275 set_bit(NFS_DEVICEID_INVALID, &d->flags); 276 } 277 rcu_read_unlock(); 278 } 279