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 #include "nfs4trace.h"
  38
  39 #define NFSDBG_FACILITY         NFSDBG_PNFS
  40
  41 /*
  42  * Device ID RCU cache. A device ID is unique per server and layout type.
  43  */
  44 #define NFS4_DEVICE_ID_HASH_BITS        5
  45 #define NFS4_DEVICE_ID_HASH_SIZE        (1 << NFS4_DEVICE_ID_HASH_BITS)
  46 #define NFS4_DEVICE_ID_HASH_MASK        (NFS4_DEVICE_ID_HASH_SIZE - 1)
  47
  48
  49 static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
  50 static DEFINE_SPINLOCK(nfs4_deviceid_lock);
  51
  52 #ifdef NFS_DEBUG
  53 void
  54 nfs4_print_deviceid(const struct nfs4_deviceid *id)
  55 {
  56         u32 *p = (u32 *)id;
  57
  58         dprintk("%s: device id= [%x%x%x%x]\n", __func__,
  59                 p[0], p[1], p[2], p[3]);
  60 }
  61 EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
  62 #endif
  63
  64 static inline u32
  65 nfs4_deviceid_hash(const struct nfs4_deviceid *id)
  66 {
  67         unsigned char *cptr = (unsigned char *)id->data;
  68         unsigned int nbytes = NFS4_DEVICEID4_SIZE;
  69         u32 x = 0;
  70
  71         while (nbytes--) {
  72                 x *= 37;
  73                 x += *cptr++;
  74         }
  75         return x & NFS4_DEVICE_ID_HASH_MASK;
  76 }
  77
  78 static struct nfs4_deviceid_node *
  79 _lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
  80                  const struct nfs_client *clp, const struct nfs4_deviceid *id,
  81                  long hash)
  82 {
  83         struct nfs4_deviceid_node *d;
  84
  85         hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
  86                 if (d->ld == ld && d->nfs_client == clp &&
  87                     !memcmp(&d->deviceid, id, sizeof(*id))) {
  88                         if (atomic_read(&d->ref))
  89                                 return d;
  90                         else
  91                                 continue;
  92                 }
  93         return NULL;
  94 }
  95
  96 static struct nfs4_deviceid_node *
  97 nfs4_get_device_info(struct nfs_server *server,
  98                 const struct nfs4_deviceid *dev_id,
  99                 const struct cred *cred, gfp_t gfp_flags)
 100 {
 101         struct nfs4_deviceid_node *d = NULL;
 102         struct pnfs_device *pdev = NULL;
 103         struct page **pages = NULL;
 104         u32 max_resp_sz;
 105         int max_pages;
 106         int rc, i;
 107
 108         /*
 109          * Use the session max response size as the basis for setting
 110          * GETDEVICEINFO's maxcount
 111          */
 112         max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
 113         if (server->pnfs_curr_ld->max_deviceinfo_size &&
 114             server->pnfs_curr_ld->max_deviceinfo_size < max_resp_sz)
 115                 max_resp_sz = server->pnfs_curr_ld->max_deviceinfo_size;
 116         max_pages = nfs_page_array_len(0, max_resp_sz);
 117         dprintk("%s: server %p max_resp_sz %u max_pages %d\n",
 118                 __func__, server, max_resp_sz, max_pages);
 119
 120         pdev = kzalloc(sizeof(*pdev), gfp_flags);
 121         if (!pdev)
 122                 return NULL;
 123
 124         pages = kcalloc(max_pages, sizeof(struct page *), gfp_flags);
 125         if (!pages)
 126                 goto out_free_pdev;
 127
 128         for (i = 0; i < max_pages; i++) {
 129                 pages[i] = alloc_page(gfp_flags);
 130                 if (!pages[i])
 131                         goto out_free_pages;
 132         }
 133
 134         memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
 135         pdev->layout_type = server->pnfs_curr_ld->id;
 136         pdev->pages = pages;
 137         pdev->pgbase = 0;
 138         pdev->pglen = max_resp_sz;
 139         pdev->mincount = 0;
 140         pdev->maxcount = max_resp_sz - nfs41_maxgetdevinfo_overhead;
 141
 142         rc = nfs4_proc_getdeviceinfo(server, pdev, cred);
 143         dprintk("%s getdevice info returns %d\n", __func__, rc);
 144         if (rc)
 145                 goto out_free_pages;
 146
 147         /*
 148          * Found new device, need to decode it and then add it to the
 149          * list of known devices for this mountpoint.
 150          */
 151         d = server->pnfs_curr_ld->alloc_deviceid_node(server, pdev,
 152                         gfp_flags);
 153         if (d && pdev->nocache)
 154                 set_bit(NFS_DEVICEID_NOCACHE, &d->flags);
 155
 156 out_free_pages:
 157         for (i = 0; i < max_pages; i++)
 158                 __free_page(pages[i]);
 159         kfree(pages);
 160 out_free_pdev:
 161         kfree(pdev);
 162         dprintk("<-- %s d %p\n", __func__, d);
 163         return d;
 164 }
 165
 166 /*
 167  * Lookup a deviceid in cache and get a reference count on it if found
 168  *
 169  * @clp nfs_client associated with deviceid
 170  * @id deviceid to look up
 171  */
 172 static struct nfs4_deviceid_node *
 173 __nfs4_find_get_deviceid(struct nfs_server *server,
 174                 const struct nfs4_deviceid *id, long hash)
 175 {
 176         struct nfs4_deviceid_node *d;
 177
 178         rcu_read_lock();
 179         d = _lookup_deviceid(server->pnfs_curr_ld, server->nfs_client, id,
 180                         hash);
 181         if (d != NULL && !atomic_inc_not_zero(&d->ref))
 182                 d = NULL;
 183         rcu_read_unlock();
 184         return d;
 185 }
 186
 187 struct nfs4_deviceid_node *
 188 nfs4_find_get_deviceid(struct nfs_server *server,
 189                 const struct nfs4_deviceid *id, const struct cred *cred,
 190                 gfp_t gfp_mask)
 191 {
 192         long hash = nfs4_deviceid_hash(id);
 193         struct nfs4_deviceid_node *d, *new;
 194
 195         d = __nfs4_find_get_deviceid(server, id, hash);
 196         if (d)
 197                 goto found;
 198
 199         new = nfs4_get_device_info(server, id, cred, gfp_mask);
 200         if (!new) {
 201                 trace_nfs4_find_deviceid(server, id, -ENOENT);
 202                 return new;
 203         }
 204
 205         spin_lock(&nfs4_deviceid_lock);
 206         d = __nfs4_find_get_deviceid(server, id, hash);
 207         if (d) {
 208                 spin_unlock(&nfs4_deviceid_lock);
 209                 server->pnfs_curr_ld->free_deviceid_node(new);
 210         } else {
 211                 atomic_inc(&new->ref);
 212                 hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
 213                 spin_unlock(&nfs4_deviceid_lock);
 214                 d = new;
 215         }
 216 found:
 217         trace_nfs4_find_deviceid(server, id, 0);
 218         return d;
 219 }
 220 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
 221
 222 /*
 223  * Remove a deviceid from cache
 224  *
 225  * @clp nfs_client associated with deviceid
 226  * @id the deviceid to unhash
 227  *
 228  * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
 229  */
 230 void
 231 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
 232                          const struct nfs_client *clp, const struct nfs4_deviceid *id)
 233 {
 234         struct nfs4_deviceid_node *d;
 235
 236         spin_lock(&nfs4_deviceid_lock);
 237         rcu_read_lock();
 238         d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
 239         rcu_read_unlock();
 240         if (!d) {
 241                 spin_unlock(&nfs4_deviceid_lock);
 242                 return;
 243         }
 244         hlist_del_init_rcu(&d->node);
 245         clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
 246         spin_unlock(&nfs4_deviceid_lock);
 247
 248         /* balance the initial ref set in pnfs_insert_deviceid */
 249         nfs4_put_deviceid_node(d);
 250 }
 251 EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
 252
 253 void
 254 nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, struct nfs_server *server,
 255                         const struct nfs4_deviceid *id)
 256 {
 257         INIT_HLIST_NODE(&d->node);
 258         INIT_HLIST_NODE(&d->tmpnode);
 259         d->ld = server->pnfs_curr_ld;
 260         d->nfs_client = server->nfs_client;
 261         d->flags = 0;
 262         d->deviceid = *id;
 263         atomic_set(&d->ref, 1);
 264 }
 265 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
 266
 267 /*
 268  * Dereference a deviceid node and delete it when its reference count drops
 269  * to zero.
 270  *
 271  * @d deviceid node to put
 272  *
 273  * return true iff the node was deleted
 274  * Note that since the test for d->ref == 0 is sufficient to establish
 275  * that the node is no longer hashed in the global device id cache.
 276  */
 277 bool
 278 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
 279 {
 280         if (test_bit(NFS_DEVICEID_NOCACHE, &d->flags)) {
 281                 if (atomic_add_unless(&d->ref, -1, 2))
 282                         return false;
 283                 nfs4_delete_deviceid(d->ld, d->nfs_client, &d->deviceid);
 284         }
 285         if (!atomic_dec_and_test(&d->ref))
 286                 return false;
 287         trace_nfs4_deviceid_free(d->nfs_client, &d->deviceid);
 288         d->ld->free_deviceid_node(d);
 289         return true;
 290 }
 291 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
 292
 293 void
 294 nfs4_mark_deviceid_available(struct nfs4_deviceid_node *node)
 295 {
 296         if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
 297                 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 298                 smp_mb__after_atomic();
 299         }
 300 }
 301 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_available);
 302
 303 void
 304 nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
 305 {
 306         node->timestamp_unavailable = jiffies;
 307         smp_mb__before_atomic();
 308         set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 309         smp_mb__after_atomic();
 310 }
 311 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
 312
 313 bool
 314 nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
 315 {
 316         if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
 317                 unsigned long start, end;
 318
 319                 end = jiffies;
 320                 start = end - PNFS_DEVICE_RETRY_TIMEOUT;
 321                 if (time_in_range(node->timestamp_unavailable, start, end))
 322                         return true;
 323                 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 324                 smp_mb__after_atomic();
 325         }
 326         return false;
 327 }
 328 EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
 329
 330 static void
 331 _deviceid_purge_client(const struct nfs_client *clp, long hash)
 332 {
 333         struct nfs4_deviceid_node *d;
 334         HLIST_HEAD(tmp);
 335
 336         spin_lock(&nfs4_deviceid_lock);
 337         rcu_read_lock();
 338         hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
 339                 if (d->nfs_client == clp && atomic_read(&d->ref)) {
 340                         hlist_del_init_rcu(&d->node);
 341                         hlist_add_head(&d->tmpnode, &tmp);
 342                         clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
 343                 }
 344         rcu_read_unlock();
 345         spin_unlock(&nfs4_deviceid_lock);
 346
 347         if (hlist_empty(&tmp))
 348                 return;
 349
 350         while (!hlist_empty(&tmp)) {
 351                 d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
 352                 hlist_del(&d->tmpnode);
 353                 nfs4_put_deviceid_node(d);
 354         }
 355 }
 356
 357 void
 358 nfs4_deviceid_purge_client(const struct nfs_client *clp)
 359 {
 360         long h;
 361
 362         if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
 363                 return;
 364         for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
 365                 _deviceid_purge_client(clp, h);
 366 }
 367
 368 /*
 369  * Stop use of all deviceids associated with an nfs_client
 370  */
 371 void
 372 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
 373 {
 374         struct nfs4_deviceid_node *d;
 375         int i;
 376
 377         rcu_read_lock();
 378         for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
 379                 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node)
 380                         if (d->nfs_client == clp)
 381                                 set_bit(NFS_DEVICEID_INVALID, &d->flags);
 382         }
 383         rcu_read_unlock();
 384 }