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 <linux/nfs_fs.h>
  33 #include "nfs4session.h"
  34 #include "internal.h"
  35 #include "pnfs.h"
  36
  37 #define NFSDBG_FACILITY         NFSDBG_PNFS
  38
  39 /*
  40  * Device ID RCU cache. A device ID is unique per server and layout type.
  41  */
  42 #define NFS4_DEVICE_ID_HASH_BITS        5
  43 #define NFS4_DEVICE_ID_HASH_SIZE        (1 << NFS4_DEVICE_ID_HASH_BITS)
  44 #define NFS4_DEVICE_ID_HASH_MASK        (NFS4_DEVICE_ID_HASH_SIZE - 1)
  45
  46 #define PNFS_DEVICE_RETRY_TIMEOUT (120*HZ)
  47
  48 static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
  49 static DEFINE_SPINLOCK(nfs4_deviceid_lock);
  50
  51 #ifdef NFS_DEBUG
  52 void
  53 nfs4_print_deviceid(const struct nfs4_deviceid *id)
  54 {
  55         u32 *p = (u32 *)id;
  56
  57         dprintk("%s: device id= [%x%x%x%x]\n", __func__,
  58                 p[0], p[1], p[2], p[3]);
  59 }
  60 EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
  61 #endif
  62
  63 static inline u32
  64 nfs4_deviceid_hash(const struct nfs4_deviceid *id)
  65 {
  66         unsigned char *cptr = (unsigned char *)id->data;
  67         unsigned int nbytes = NFS4_DEVICEID4_SIZE;
  68         u32 x = 0;
  69
  70         while (nbytes--) {
  71                 x *= 37;
  72                 x += *cptr++;
  73         }
  74         return x & NFS4_DEVICE_ID_HASH_MASK;
  75 }
  76
  77 static struct nfs4_deviceid_node *
  78 _lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
  79                  const struct nfs_client *clp, const struct nfs4_deviceid *id,
  80                  long hash)
  81 {
  82         struct nfs4_deviceid_node *d;
  83
  84         hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
  85                 if (d->ld == ld && d->nfs_client == clp &&
  86                     !memcmp(&d->deviceid, id, sizeof(*id))) {
  87                         if (atomic_read(&d->ref))
  88                                 return d;
  89                         else
  90                                 continue;
  91                 }
  92         return NULL;
  93 }
  94
  95 static struct nfs4_deviceid_node *
  96 nfs4_get_device_info(struct nfs_server *server,
  97                 const struct nfs4_deviceid *dev_id,
  98                 struct rpc_cred *cred, gfp_t gfp_flags)
  99 {
 100         struct nfs4_deviceid_node *d = NULL;
 101         struct pnfs_device *pdev = NULL;
 102         struct page **pages = NULL;
 103         u32 max_resp_sz;
 104         int max_pages;
 105         int rc, i;
 106
 107         /*
 108          * Use the session max response size as the basis for setting
 109          * GETDEVICEINFO's maxcount
 110          */
 111         max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
 112         if (server->pnfs_curr_ld->max_deviceinfo_size &&
 113             server->pnfs_curr_ld->max_deviceinfo_size < max_resp_sz)
 114                 max_resp_sz = server->pnfs_curr_ld->max_deviceinfo_size;
 115         max_pages = nfs_page_array_len(0, max_resp_sz);
 116         dprintk("%s: server %p max_resp_sz %u max_pages %d\n",
 117                 __func__, server, max_resp_sz, max_pages);
 118
 119         pdev = kzalloc(sizeof(*pdev), gfp_flags);
 120         if (!pdev)
 121                 return NULL;
 122
 123         pages = kcalloc(max_pages, sizeof(struct page *), gfp_flags);
 124         if (!pages)
 125                 goto out_free_pdev;
 126
 127         for (i = 0; i < max_pages; i++) {
 128                 pages[i] = alloc_page(gfp_flags);
 129                 if (!pages[i])
 130                         goto out_free_pages;
 131         }
 132
 133         memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
 134         pdev->layout_type = server->pnfs_curr_ld->id;
 135         pdev->pages = pages;
 136         pdev->pgbase = 0;
 137         pdev->pglen = max_resp_sz;
 138         pdev->mincount = 0;
 139         pdev->maxcount = max_resp_sz - nfs41_maxgetdevinfo_overhead;
 140
 141         rc = nfs4_proc_getdeviceinfo(server, pdev, cred);
 142         dprintk("%s getdevice info returns %d\n", __func__, rc);
 143         if (rc)
 144                 goto out_free_pages;
 145
 146         /*
 147          * Found new device, need to decode it and then add it to the
 148          * list of known devices for this mountpoint.
 149          */
 150         d = server->pnfs_curr_ld->alloc_deviceid_node(server, pdev,
 151                         gfp_flags);
 152
 153 out_free_pages:
 154         for (i = 0; i < max_pages; i++)
 155                 __free_page(pages[i]);
 156         kfree(pages);
 157 out_free_pdev:
 158         kfree(pdev);
 159         dprintk("<-- %s d %p\n", __func__, d);
 160         return d;
 161 }
 162
 163 /*
 164  * Lookup a deviceid in cache and get a reference count on it if found
 165  *
 166  * @clp nfs_client associated with deviceid
 167  * @id deviceid to look up
 168  */
 169 static struct nfs4_deviceid_node *
 170 __nfs4_find_get_deviceid(struct nfs_server *server,
 171                 const struct nfs4_deviceid *id, long hash)
 172 {
 173         struct nfs4_deviceid_node *d;
 174
 175         rcu_read_lock();
 176         d = _lookup_deviceid(server->pnfs_curr_ld, server->nfs_client, id,
 177                         hash);
 178         if (d != NULL)
 179                 atomic_inc(&d->ref);
 180         rcu_read_unlock();
 181         return d;
 182 }
 183
 184 struct nfs4_deviceid_node *
 185 nfs4_find_get_deviceid(struct nfs_server *server,
 186                 const struct nfs4_deviceid *id, struct rpc_cred *cred,
 187                 gfp_t gfp_mask)
 188 {
 189         long hash = nfs4_deviceid_hash(id);
 190         struct nfs4_deviceid_node *d, *new;
 191
 192         d = __nfs4_find_get_deviceid(server, id, hash);
 193         if (d)
 194                 return d;
 195
 196         new = nfs4_get_device_info(server, id, cred, gfp_mask);
 197         if (!new)
 198                 return new;
 199
 200         spin_lock(&nfs4_deviceid_lock);
 201         d = __nfs4_find_get_deviceid(server, id, hash);
 202         if (d) {
 203                 spin_unlock(&nfs4_deviceid_lock);
 204                 server->pnfs_curr_ld->free_deviceid_node(new);
 205                 return d;
 206         }
 207         hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
 208         atomic_inc(&new->ref);
 209         spin_unlock(&nfs4_deviceid_lock);
 210
 211         return new;
 212 }
 213 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
 214
 215 /*
 216  * Remove a deviceid from cache
 217  *
 218  * @clp nfs_client associated with deviceid
 219  * @id the deviceid to unhash
 220  *
 221  * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
 222  */
 223 void
 224 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
 225                          const struct nfs_client *clp, const struct nfs4_deviceid *id)
 226 {
 227         struct nfs4_deviceid_node *d;
 228
 229         spin_lock(&nfs4_deviceid_lock);
 230         rcu_read_lock();
 231         d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
 232         rcu_read_unlock();
 233         if (!d) {
 234                 spin_unlock(&nfs4_deviceid_lock);
 235                 return;
 236         }
 237         hlist_del_init_rcu(&d->node);
 238         spin_unlock(&nfs4_deviceid_lock);
 239         synchronize_rcu();
 240
 241         /* balance the initial ref set in pnfs_insert_deviceid */
 242         if (atomic_dec_and_test(&d->ref))
 243                 d->ld->free_deviceid_node(d);
 244 }
 245 EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
 246
 247 void
 248 nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, struct nfs_server *server,
 249                         const struct nfs4_deviceid *id)
 250 {
 251         INIT_HLIST_NODE(&d->node);
 252         INIT_HLIST_NODE(&d->tmpnode);
 253         d->ld = server->pnfs_curr_ld;
 254         d->nfs_client = server->nfs_client;
 255         d->flags = 0;
 256         d->deviceid = *id;
 257         atomic_set(&d->ref, 1);
 258 }
 259 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
 260
 261 /*
 262  * Dereference a deviceid node and delete it when its reference count drops
 263  * to zero.
 264  *
 265  * @d deviceid node to put
 266  *
 267  * return true iff the node was deleted
 268  * Note that since the test for d->ref == 0 is sufficient to establish
 269  * that the node is no longer hashed in the global device id cache.
 270  */
 271 bool
 272 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
 273 {
 274         if (!atomic_dec_and_test(&d->ref))
 275                 return false;
 276         d->ld->free_deviceid_node(d);
 277         return true;
 278 }
 279 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
 280
 281 void
 282 nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
 283 {
 284         node->timestamp_unavailable = jiffies;
 285         set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 286 }
 287 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
 288
 289 bool
 290 nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
 291 {
 292         if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
 293                 unsigned long start, end;
 294
 295                 end = jiffies;
 296                 start = end - PNFS_DEVICE_RETRY_TIMEOUT;
 297                 if (time_in_range(node->timestamp_unavailable, start, end))
 298                         return true;
 299                 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 300         }
 301         return false;
 302 }
 303 EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
 304
 305 static void
 306 _deviceid_purge_client(const struct nfs_client *clp, long hash)
 307 {
 308         struct nfs4_deviceid_node *d;
 309         HLIST_HEAD(tmp);
 310
 311         spin_lock(&nfs4_deviceid_lock);
 312         rcu_read_lock();
 313         hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
 314                 if (d->nfs_client == clp && atomic_read(&d->ref)) {
 315                         hlist_del_init_rcu(&d->node);
 316                         hlist_add_head(&d->tmpnode, &tmp);
 317                 }
 318         rcu_read_unlock();
 319         spin_unlock(&nfs4_deviceid_lock);
 320
 321         if (hlist_empty(&tmp))
 322                 return;
 323
 324         synchronize_rcu();
 325         while (!hlist_empty(&tmp)) {
 326                 d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
 327                 hlist_del(&d->tmpnode);
 328                 if (atomic_dec_and_test(&d->ref))
 329                         d->ld->free_deviceid_node(d);
 330         }
 331 }
 332
 333 void
 334 nfs4_deviceid_purge_client(const struct nfs_client *clp)
 335 {
 336         long h;
 337
 338         if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
 339                 return;
 340         for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
 341                 _deviceid_purge_client(clp, h);
 342 }
 343
 344 /*
 345  * Stop use of all deviceids associated with an nfs_client
 346  */
 347 void
 348 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
 349 {
 350         struct nfs4_deviceid_node *d;
 351         int i;
 352
 353         rcu_read_lock();
 354         for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
 355                 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node)
 356                         if (d->nfs_client == clp)
 357                                 set_bit(NFS_DEVICEID_INVALID, &d->flags);
 358         }
 359         rcu_read_unlock();
 360 }