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 struct hlist_node *n; 81 82 hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node) 83 if (d->ld == ld && d->nfs_client == clp && 84 !memcmp(&d->deviceid, id, sizeof(*id))) { 85 if (atomic_read(&d->ref)) 86 return d; 87 else 88 continue; 89 } 90 return NULL; 91 } 92 93 /* 94 * Lookup a deviceid in cache and get a reference count on it if found 95 * 96 * @clp nfs_client associated with deviceid 97 * @id deviceid to look up 98 */ 99 static struct nfs4_deviceid_node * 100 _find_get_deviceid(const struct pnfs_layoutdriver_type *ld, 101 const struct nfs_client *clp, const struct nfs4_deviceid *id, 102 long hash) 103 { 104 struct nfs4_deviceid_node *d; 105 106 rcu_read_lock(); 107 d = _lookup_deviceid(ld, clp, id, hash); 108 if (d != NULL) 109 atomic_inc(&d->ref); 110 rcu_read_unlock(); 111 return d; 112 } 113 114 struct nfs4_deviceid_node * 115 nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld, 116 const struct nfs_client *clp, const struct nfs4_deviceid *id) 117 { 118 return _find_get_deviceid(ld, clp, id, nfs4_deviceid_hash(id)); 119 } 120 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid); 121 122 /* 123 * Remove a deviceid from cache 124 * 125 * @clp nfs_client associated with deviceid 126 * @id the deviceid to unhash 127 * 128 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise. 129 */ 130 void 131 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld, 132 const struct nfs_client *clp, const struct nfs4_deviceid *id) 133 { 134 struct nfs4_deviceid_node *d; 135 136 spin_lock(&nfs4_deviceid_lock); 137 rcu_read_lock(); 138 d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id)); 139 rcu_read_unlock(); 140 if (!d) { 141 spin_unlock(&nfs4_deviceid_lock); 142 return; 143 } 144 hlist_del_init_rcu(&d->node); 145 spin_unlock(&nfs4_deviceid_lock); 146 synchronize_rcu(); 147 148 /* balance the initial ref set in pnfs_insert_deviceid */ 149 if (atomic_dec_and_test(&d->ref)) 150 d->ld->free_deviceid_node(d); 151 } 152 EXPORT_SYMBOL_GPL(nfs4_delete_deviceid); 153 154 void 155 nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, 156 const struct pnfs_layoutdriver_type *ld, 157 const struct nfs_client *nfs_client, 158 const struct nfs4_deviceid *id) 159 { 160 INIT_HLIST_NODE(&d->node); 161 INIT_HLIST_NODE(&d->tmpnode); 162 d->ld = ld; 163 d->nfs_client = nfs_client; 164 d->flags = 0; 165 d->deviceid = *id; 166 atomic_set(&d->ref, 1); 167 } 168 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node); 169 170 /* 171 * Uniquely initialize and insert a deviceid node into cache 172 * 173 * @new new deviceid node 174 * Note that the caller must set up the following members: 175 * new->ld 176 * new->nfs_client 177 * new->deviceid 178 * 179 * @ret the inserted node, if none found, otherwise, the found entry. 180 */ 181 struct nfs4_deviceid_node * 182 nfs4_insert_deviceid_node(struct nfs4_deviceid_node *new) 183 { 184 struct nfs4_deviceid_node *d; 185 long hash; 186 187 spin_lock(&nfs4_deviceid_lock); 188 hash = nfs4_deviceid_hash(&new->deviceid); 189 d = _find_get_deviceid(new->ld, new->nfs_client, &new->deviceid, hash); 190 if (d) { 191 spin_unlock(&nfs4_deviceid_lock); 192 return d; 193 } 194 195 hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]); 196 spin_unlock(&nfs4_deviceid_lock); 197 atomic_inc(&new->ref); 198 199 return new; 200 } 201 EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node); 202 203 /* 204 * Dereference a deviceid node and delete it when its reference count drops 205 * to zero. 206 * 207 * @d deviceid node to put 208 * 209 * return true iff the node was deleted 210 * Note that since the test for d->ref == 0 is sufficient to establish 211 * that the node is no longer hashed in the global device id cache. 212 */ 213 bool 214 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d) 215 { 216 if (!atomic_dec_and_test(&d->ref)) 217 return false; 218 d->ld->free_deviceid_node(d); 219 return true; 220 } 221 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node); 222 223 void 224 nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node) 225 { 226 node->timestamp_unavailable = jiffies; 227 set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags); 228 } 229 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable); 230 231 bool 232 nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node) 233 { 234 if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) { 235 unsigned long start, end; 236 237 end = jiffies; 238 start = end - PNFS_DEVICE_RETRY_TIMEOUT; 239 if (time_in_range(node->timestamp_unavailable, start, end)) 240 return true; 241 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags); 242 } 243 return false; 244 } 245 EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable); 246 247 static void 248 _deviceid_purge_client(const struct nfs_client *clp, long hash) 249 { 250 struct nfs4_deviceid_node *d; 251 struct hlist_node *n; 252 HLIST_HEAD(tmp); 253 254 spin_lock(&nfs4_deviceid_lock); 255 rcu_read_lock(); 256 hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[hash], node) 257 if (d->nfs_client == clp && atomic_read(&d->ref)) { 258 hlist_del_init_rcu(&d->node); 259 hlist_add_head(&d->tmpnode, &tmp); 260 } 261 rcu_read_unlock(); 262 spin_unlock(&nfs4_deviceid_lock); 263 264 if (hlist_empty(&tmp)) 265 return; 266 267 synchronize_rcu(); 268 while (!hlist_empty(&tmp)) { 269 d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode); 270 hlist_del(&d->tmpnode); 271 if (atomic_dec_and_test(&d->ref)) 272 d->ld->free_deviceid_node(d); 273 } 274 } 275 276 void 277 nfs4_deviceid_purge_client(const struct nfs_client *clp) 278 { 279 long h; 280 281 if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS)) 282 return; 283 for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++) 284 _deviceid_purge_client(clp, h); 285 } 286 287 /* 288 * Stop use of all deviceids associated with an nfs_client 289 */ 290 void 291 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp) 292 { 293 struct nfs4_deviceid_node *d; 294 struct hlist_node *n; 295 int i; 296 297 rcu_read_lock(); 298 for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){ 299 hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[i], node) 300 if (d->nfs_client == clp) 301 set_bit(NFS_DEVICEID_INVALID, &d->flags); 302 } 303 rcu_read_unlock(); 304 } 305 306