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 #define PNFS_DEVICE_RETRY_TIMEOUT (120*HZ) 44 45 static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE]; 46 static DEFINE_SPINLOCK(nfs4_deviceid_lock); 47 48 #ifdef NFS_DEBUG 49 void 50 nfs4_print_deviceid(const struct nfs4_deviceid *id) 51 { 52 u32 *p = (u32 *)id; 53 54 dprintk("%s: device id= [%x%x%x%x]\n", __func__, 55 p[0], p[1], p[2], p[3]); 56 } 57 EXPORT_SYMBOL_GPL(nfs4_print_deviceid); 58 #endif 59 60 static inline u32 61 nfs4_deviceid_hash(const struct nfs4_deviceid *id) 62 { 63 unsigned char *cptr = (unsigned char *)id->data; 64 unsigned int nbytes = NFS4_DEVICEID4_SIZE; 65 u32 x = 0; 66 67 while (nbytes--) { 68 x *= 37; 69 x += *cptr++; 70 } 71 return x & NFS4_DEVICE_ID_HASH_MASK; 72 } 73 74 static struct nfs4_deviceid_node * 75 _lookup_deviceid(const struct pnfs_layoutdriver_type *ld, 76 const struct nfs_client *clp, const struct nfs4_deviceid *id, 77 long hash) 78 { 79 struct nfs4_deviceid_node *d; 80 81 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node) 82 if (d->ld == ld && d->nfs_client == clp && 83 !memcmp(&d->deviceid, id, sizeof(*id))) { 84 if (atomic_read(&d->ref)) 85 return d; 86 else 87 continue; 88 } 89 return NULL; 90 } 91 92 /* 93 * Lookup a deviceid in cache and get a reference count on it if found 94 * 95 * @clp nfs_client associated with deviceid 96 * @id deviceid to look up 97 */ 98 static struct nfs4_deviceid_node * 99 _find_get_deviceid(const struct pnfs_layoutdriver_type *ld, 100 const struct nfs_client *clp, const struct nfs4_deviceid *id, 101 long hash) 102 { 103 struct nfs4_deviceid_node *d; 104 105 rcu_read_lock(); 106 d = _lookup_deviceid(ld, clp, id, hash); 107 if (d != NULL) 108 atomic_inc(&d->ref); 109 rcu_read_unlock(); 110 return d; 111 } 112 113 struct nfs4_deviceid_node * 114 nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld, 115 const struct nfs_client *clp, const struct nfs4_deviceid *id) 116 { 117 return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id)); 118 } 119 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid); 120 121 /* 122 * Remove a deviceid from cache 123 * 124 * @clp nfs_client associated with deviceid 125 * @id the deviceid to unhash 126 * 127 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise. 128 */ 129 void 130 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld, 131 const struct nfs_client *clp, const struct nfs4_deviceid *id) 132 { 133 struct nfs4_deviceid_node *d; 134 135 spin_lock(&nfs4_deviceid_lock); 136 rcu_read_lock(); 137 d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id)); 138 rcu_read_unlock(); 139 if (!d) { 140 spin_unlock(&nfs4_deviceid_lock); 141 return; 142 } 143 hlist_del_init_rcu(&d->node); 144 spin_unlock(&nfs4_deviceid_lock); 145 synchronize_rcu(); 146 147 /* balance the initial ref set in pnfs_insert_deviceid */ 148 if (atomic_dec_and_test(&d->ref)) 149 d->ld->free_deviceid_node(d); 150 } 151 EXPORT_SYMBOL_GPL(nfs4_delete_deviceid); 152 153 void 154 nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, 155 const struct pnfs_layoutdriver_type *ld, 156 const struct nfs_client *nfs_client, 157 const struct nfs4_deviceid *id) 158 { 159 INIT_HLIST_NODE(&d->node); 160 INIT_HLIST_NODE(&d->tmpnode); 161 d->ld = ld; 162 d->nfs_client = nfs_client; 163 d->flags = 0; 164 d->deviceid = *id; 165 atomic_set(&d->ref, 1); 166 } 167 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node); 168 169 /* 170 * Uniquely initialize and insert a deviceid node into cache 171 * 172 * @new new deviceid node 173 * Note that the caller must set up the following members: 174 * new->ld 175 * new->nfs_client 176 * new->deviceid 177 * 178 * @ret the inserted node, if none found, otherwise, the found entry. 179 */ 180 struct nfs4_deviceid_node * 181 nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new) 182 { 183 struct nfs4_deviceid_node *d; 184 long hash; 185 186 spin_lock(&nfs4_deviceid_lock); 187 hash = nfs4_deviceid_hash(&new->deviceid); 188 d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash); 189 if (d) { 190 spin_unlock(&nfs4_deviceid_lock); 191 return d; 192 } 193 194 hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]); 195 spin_unlock(&nfs4_deviceid_lock); 196 atomic_inc(&new->ref); 197 198 return new; 199 } 200 EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node); 201 202 /* 203 * Dereference a deviceid node and delete it when its reference count drops 204 * to zero. 205 * 206 * @d deviceid node to put 207 * 208 * return true iff the node was deleted 209 * Note that since the test for d->ref == 0 is sufficient to establish 210 * that the node is no longer hashed in the global device id cache. 211 */ 212 bool 213 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d) 214 { 215 if (!atomic_dec_and_test(&d->ref)) 216 return false; 217 d->ld->free_deviceid_node(d); 218 return true; 219 } 220 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node); 221 222 void 223 nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node) 224 { 225 node->timestamp_unavailable = jiffies; 226 set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags); 227 } 228 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable); 229 230 bool 231 nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node) 232 { 233 if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) { 234 unsigned long start, end; 235 236 end = jiffies; 237 start = end - PNFS_DEVICE_RETRY_TIMEOUT; 238 if (time_in_range(node->timestamp_unavailable, start, end)) 239 return true; 240 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags); 241 } 242 return false; 243 } 244 EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable); 245 246 static void 247 _deviceid_purge_client(const struct nfs_client *clp, long hash) 248 { 249 struct nfs4_deviceid_node *d; 250 HLIST_HEAD(tmp); 251 252 spin_lock(&nfs4_deviceid_lock); 253 rcu_read_lock(); 254 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node) 255 if (d->nfs_client == clp && atomic_read(&d->ref)) { 256 hlist_del_init_rcu(&d->node); 257 hlist_add_head(&d->tmpnode, &tmp); 258 } 259 rcu_read_unlock(); 260 spin_unlock(&nfs4_deviceid_lock); 261 262 if (hlist_empty(&tmp)) 263 return; 264 265 synchronize_rcu(); 266 while (!hlist_empty(&tmp)) { 267 d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode); 268 hlist_del(&d->tmpnode); 269 if (atomic_dec_and_test(&d->ref)) 270 d->ld->free_deviceid_node(d); 271 } 272 } 273 274 void 275 nfs4_deviceid_purge_client(const struct nfs_client *clp) 276 { 277 long h; 278 279 if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS)) 280 return; 281 for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++) 282 _deviceid_purge_client(clp, h); 283 } 284 285 /* 286 * Stop use of all deviceids associated with an nfs_client 287 */ 288 void 289 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp) 290 { 291 struct nfs4_deviceid_node *d; 292 int i; 293 294 rcu_read_lock(); 295 for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){ 296 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node) 297 if (d->nfs_client == clp) 298 set_bit(NFS_DEVICEID_INVALID, &d->flags); 299 } 300 rcu_read_unlock(); 301 } 302 303