fs/nfs/pnfs_dev.c

   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