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         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