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
  47 static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE];
  48 static DEFINE_SPINLOCK(nfs4_deviceid_lock);
  49
  50 #ifdef NFS_DEBUG
  51 void
  52 nfs4_print_deviceid(const struct nfs4_deviceid *id)
  53 {
  54         u32 *p = (u32 *)id;
  55
  56         dprintk("%s: device id= [%x%x%x%x]\n", __func__,
  57                 p[0], p[1], p[2], p[3]);
  58 }
  59 EXPORT_SYMBOL_GPL(nfs4_print_deviceid);
  60 #endif
  61
  62 static inline u32
  63 nfs4_deviceid_hash(const struct nfs4_deviceid *id)
  64 {
  65         unsigned char *cptr = (unsigned char *)id->data;
  66         unsigned int nbytes = NFS4_DEVICEID4_SIZE;
  67         u32 x = 0;
  68
  69         while (nbytes--) {
  70                 x *= 37;
  71                 x += *cptr++;
  72         }
  73         return x & NFS4_DEVICE_ID_HASH_MASK;
  74 }
  75
  76 static struct nfs4_deviceid_node *
  77 _lookup_deviceid(const struct pnfs_layoutdriver_type *ld,
  78                  const struct nfs_client *clp, const struct nfs4_deviceid *id,
  79                  long hash)
  80 {
  81         struct nfs4_deviceid_node *d;
  82
  83         hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
  84                 if (d->ld == ld && d->nfs_client == clp &&
  85                     !memcmp(&d->deviceid, id, sizeof(*id))) {
  86                         if (atomic_read(&d->ref))
  87                                 return d;
  88                         else
  89                                 continue;
  90                 }
  91         return NULL;
  92 }
  93
  94 static struct nfs4_deviceid_node *
  95 nfs4_get_device_info(struct nfs_server *server,
  96                 const struct nfs4_deviceid *dev_id,
  97                 const struct cred *cred, gfp_t gfp_flags)
  98 {
  99         struct nfs4_deviceid_node *d = NULL;
 100         struct pnfs_device *pdev = NULL;
 101         struct page **pages = NULL;
 102         u32 max_resp_sz;
 103         int max_pages;
 104         int rc, i;
 105
 106         /*
 107          * Use the session max response size as the basis for setting
 108          * GETDEVICEINFO's maxcount
 109          */
 110         max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
 111         if (server->pnfs_curr_ld->max_deviceinfo_size &&
 112             server->pnfs_curr_ld->max_deviceinfo_size < max_resp_sz)
 113                 max_resp_sz = server->pnfs_curr_ld->max_deviceinfo_size;
 114         max_pages = nfs_page_array_len(0, max_resp_sz);
 115         dprintk("%s: server %p max_resp_sz %u max_pages %d\n",
 116                 __func__, server, max_resp_sz, max_pages);
 117
 118         pdev = kzalloc(sizeof(*pdev), gfp_flags);
 119         if (!pdev)
 120                 return NULL;
 121
 122         pages = kcalloc(max_pages, sizeof(struct page *), gfp_flags);
 123         if (!pages)
 124                 goto out_free_pdev;
 125
 126         for (i = 0; i < max_pages; i++) {
 127                 pages[i] = alloc_page(gfp_flags);
 128                 if (!pages[i])
 129                         goto out_free_pages;
 130         }
 131
 132         memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
 133         pdev->layout_type = server->pnfs_curr_ld->id;
 134         pdev->pages = pages;
 135         pdev->pgbase = 0;
 136         pdev->pglen = max_resp_sz;
 137         pdev->mincount = 0;
 138         pdev->maxcount = max_resp_sz - nfs41_maxgetdevinfo_overhead;
 139
 140         rc = nfs4_proc_getdeviceinfo(server, pdev, cred);
 141         dprintk("%s getdevice info returns %d\n", __func__, rc);
 142         if (rc)
 143                 goto out_free_pages;
 144
 145         /*
 146          * Found new device, need to decode it and then add it to the
 147          * list of known devices for this mountpoint.
 148          */
 149         d = server->pnfs_curr_ld->alloc_deviceid_node(server, pdev,
 150                         gfp_flags);
 151         if (d && pdev->nocache)
 152                 set_bit(NFS_DEVICEID_NOCACHE, &d->flags);
 153
 154 out_free_pages:
 155         for (i = 0; i < max_pages; i++)
 156                 __free_page(pages[i]);
 157         kfree(pages);
 158 out_free_pdev:
 159         kfree(pdev);
 160         dprintk("<-- %s d %p\n", __func__, d);
 161         return d;
 162 }
 163
 164 /*
 165  * Lookup a deviceid in cache and get a reference count on it if found
 166  *
 167  * @clp nfs_client associated with deviceid
 168  * @id deviceid to look up
 169  */
 170 static struct nfs4_deviceid_node *
 171 __nfs4_find_get_deviceid(struct nfs_server *server,
 172                 const struct nfs4_deviceid *id, long hash)
 173 {
 174         struct nfs4_deviceid_node *d;
 175
 176         rcu_read_lock();
 177         d = _lookup_deviceid(server->pnfs_curr_ld, server->nfs_client, id,
 178                         hash);
 179         if (d != NULL && !atomic_inc_not_zero(&d->ref))
 180                 d = NULL;
 181         rcu_read_unlock();
 182         return d;
 183 }
 184
 185 struct nfs4_deviceid_node *
 186 nfs4_find_get_deviceid(struct nfs_server *server,
 187                 const struct nfs4_deviceid *id, const struct cred *cred,
 188                 gfp_t gfp_mask)
 189 {
 190         long hash = nfs4_deviceid_hash(id);
 191         struct nfs4_deviceid_node *d, *new;
 192
 193         d = __nfs4_find_get_deviceid(server, id, hash);
 194         if (d)
 195                 return d;
 196
 197         new = nfs4_get_device_info(server, id, cred, gfp_mask);
 198         if (!new)
 199                 return new;
 200
 201         spin_lock(&nfs4_deviceid_lock);
 202         d = __nfs4_find_get_deviceid(server, id, hash);
 203         if (d) {
 204                 spin_unlock(&nfs4_deviceid_lock);
 205                 server->pnfs_curr_ld->free_deviceid_node(new);
 206                 return d;
 207         }
 208         hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
 209         atomic_inc(&new->ref);
 210         spin_unlock(&nfs4_deviceid_lock);
 211
 212         return new;
 213 }
 214 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
 215
 216 /*
 217  * Remove a deviceid from cache
 218  *
 219  * @clp nfs_client associated with deviceid
 220  * @id the deviceid to unhash
 221  *
 222  * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
 223  */
 224 void
 225 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
 226                          const struct nfs_client *clp, const struct nfs4_deviceid *id)
 227 {
 228         struct nfs4_deviceid_node *d;
 229
 230         spin_lock(&nfs4_deviceid_lock);
 231         rcu_read_lock();
 232         d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
 233         rcu_read_unlock();
 234         if (!d) {
 235                 spin_unlock(&nfs4_deviceid_lock);
 236                 return;
 237         }
 238         hlist_del_init_rcu(&d->node);
 239         clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
 240         spin_unlock(&nfs4_deviceid_lock);
 241
 242         /* balance the initial ref set in pnfs_insert_deviceid */
 243         nfs4_put_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 (test_bit(NFS_DEVICEID_NOCACHE, &d->flags)) {
 275                 if (atomic_add_unless(&d->ref, -1, 2))
 276                         return false;
 277                 nfs4_delete_deviceid(d->ld, d->nfs_client, &d->deviceid);
 278         }
 279         if (!atomic_dec_and_test(&d->ref))
 280                 return false;
 281         d->ld->free_deviceid_node(d);
 282         return true;
 283 }
 284 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
 285
 286 void
 287 nfs4_mark_deviceid_available(struct nfs4_deviceid_node *node)
 288 {
 289         if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
 290                 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 291                 smp_mb__after_atomic();
 292         }
 293 }
 294 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_available);
 295
 296 void
 297 nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
 298 {
 299         node->timestamp_unavailable = jiffies;
 300         smp_mb__before_atomic();
 301         set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 302         smp_mb__after_atomic();
 303 }
 304 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
 305
 306 bool
 307 nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
 308 {
 309         if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
 310                 unsigned long start, end;
 311
 312                 end = jiffies;
 313                 start = end - PNFS_DEVICE_RETRY_TIMEOUT;
 314                 if (time_in_range(node->timestamp_unavailable, start, end))
 315                         return true;
 316                 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 317                 smp_mb__after_atomic();
 318         }
 319         return false;
 320 }
 321 EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
 322
 323 static void
 324 _deviceid_purge_client(const struct nfs_client *clp, long hash)
 325 {
 326         struct nfs4_deviceid_node *d;
 327         HLIST_HEAD(tmp);
 328
 329         spin_lock(&nfs4_deviceid_lock);
 330         rcu_read_lock();
 331         hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
 332                 if (d->nfs_client == clp && atomic_read(&d->ref)) {
 333                         hlist_del_init_rcu(&d->node);
 334                         hlist_add_head(&d->tmpnode, &tmp);
 335                         clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
 336                 }
 337         rcu_read_unlock();
 338         spin_unlock(&nfs4_deviceid_lock);
 339
 340         if (hlist_empty(&tmp))
 341                 return;
 342
 343         while (!hlist_empty(&tmp)) {
 344                 d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
 345                 hlist_del(&d->tmpnode);
 346                 nfs4_put_deviceid_node(d);
 347         }
 348 }
 349
 350 void
 351 nfs4_deviceid_purge_client(const struct nfs_client *clp)
 352 {
 353         long h;
 354
 355         if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
 356                 return;
 357         for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
 358                 _deviceid_purge_client(clp, h);
 359 }
 360
 361 /*
 362  * Stop use of all deviceids associated with an nfs_client
 363  */
 364 void
 365 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
 366 {
 367         struct nfs4_deviceid_node *d;
 368         int i;
 369
 370         rcu_read_lock();
 371         for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
 372                 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node)
 373                         if (d->nfs_client == clp)
 374                                 set_bit(NFS_DEVICEID_INVALID, &d->flags);
 375         }
 376         rcu_read_unlock();
 377 }