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         max_pages = nfs_page_array_len(0, max_resp_sz);
 114         dprintk("%s: server %p max_resp_sz %u max_pages %d\n",
 115                 __func__, server, max_resp_sz, max_pages);
 116
 117         pdev = kzalloc(sizeof(*pdev), gfp_flags);
 118         if (!pdev)
 119                 return NULL;
 120
 121         pages = kcalloc(max_pages, sizeof(struct page *), gfp_flags);
 122         if (!pages)
 123                 goto out_free_pdev;
 124
 125         for (i = 0; i < max_pages; i++) {
 126                 pages[i] = alloc_page(gfp_flags);
 127                 if (!pages[i])
 128                         goto out_free_pages;
 129         }
 130
 131         memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
 132         pdev->layout_type = server->pnfs_curr_ld->id;
 133         pdev->pages = pages;
 134         pdev->pgbase = 0;
 135         pdev->pglen = max_resp_sz;
 136         pdev->mincount = 0;
 137         pdev->maxcount = max_resp_sz - nfs41_maxgetdevinfo_overhead;
 138
 139         rc = nfs4_proc_getdeviceinfo(server, pdev, cred);
 140         dprintk("%s getdevice info returns %d\n", __func__, rc);
 141         if (rc)
 142                 goto out_free_pages;
 143
 144         /*
 145          * Found new device, need to decode it and then add it to the
 146          * list of known devices for this mountpoint.
 147          */
 148         d = server->pnfs_curr_ld->alloc_deviceid_node(server, pdev,
 149                         gfp_flags);
 150         if (d && pdev->nocache)
 151                 set_bit(NFS_DEVICEID_NOCACHE, &d->flags);
 152
 153 out_free_pages:
 154         while (--i >= 0)
 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 && !atomic_inc_not_zero(&d->ref))
 179                 d = NULL;
 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, const struct 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                 goto found;
 195
 196         new = nfs4_get_device_info(server, id, cred, gfp_mask);
 197         if (!new) {
 198                 trace_nfs4_find_deviceid(server, id, -ENOENT);
 199                 return new;
 200         }
 201
 202         spin_lock(&nfs4_deviceid_lock);
 203         d = __nfs4_find_get_deviceid(server, id, hash);
 204         if (d) {
 205                 spin_unlock(&nfs4_deviceid_lock);
 206                 server->pnfs_curr_ld->free_deviceid_node(new);
 207         } else {
 208                 atomic_inc(&new->ref);
 209                 hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]);
 210                 spin_unlock(&nfs4_deviceid_lock);
 211                 d = new;
 212         }
 213 found:
 214         trace_nfs4_find_deviceid(server, id, 0);
 215         return d;
 216 }
 217 EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
 218
 219 /*
 220  * Remove a deviceid from cache
 221  *
 222  * @clp nfs_client associated with deviceid
 223  * @id the deviceid to unhash
 224  *
 225  * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.
 226  */
 227 void
 228 nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,
 229                          const struct nfs_client *clp, const struct nfs4_deviceid *id)
 230 {
 231         struct nfs4_deviceid_node *d;
 232
 233         spin_lock(&nfs4_deviceid_lock);
 234         rcu_read_lock();
 235         d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id));
 236         rcu_read_unlock();
 237         if (!d) {
 238                 spin_unlock(&nfs4_deviceid_lock);
 239                 return;
 240         }
 241         hlist_del_init_rcu(&d->node);
 242         clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
 243         spin_unlock(&nfs4_deviceid_lock);
 244
 245         /* balance the initial ref set in pnfs_insert_deviceid */
 246         nfs4_put_deviceid_node(d);
 247 }
 248 EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
 249
 250 void
 251 nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, struct nfs_server *server,
 252                         const struct nfs4_deviceid *id)
 253 {
 254         INIT_HLIST_NODE(&d->node);
 255         INIT_HLIST_NODE(&d->tmpnode);
 256         d->ld = server->pnfs_curr_ld;
 257         d->nfs_client = server->nfs_client;
 258         d->flags = 0;
 259         d->deviceid = *id;
 260         atomic_set(&d->ref, 1);
 261 }
 262 EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node);
 263
 264 /*
 265  * Dereference a deviceid node and delete it when its reference count drops
 266  * to zero.
 267  *
 268  * @d deviceid node to put
 269  *
 270  * return true iff the node was deleted
 271  * Note that since the test for d->ref == 0 is sufficient to establish
 272  * that the node is no longer hashed in the global device id cache.
 273  */
 274 bool
 275 nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)
 276 {
 277         if (test_bit(NFS_DEVICEID_NOCACHE, &d->flags)) {
 278                 if (atomic_add_unless(&d->ref, -1, 2))
 279                         return false;
 280                 nfs4_delete_deviceid(d->ld, d->nfs_client, &d->deviceid);
 281         }
 282         if (!atomic_dec_and_test(&d->ref))
 283                 return false;
 284         trace_nfs4_deviceid_free(d->nfs_client, &d->deviceid);
 285         d->ld->free_deviceid_node(d);
 286         return true;
 287 }
 288 EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node);
 289
 290 void
 291 nfs4_mark_deviceid_available(struct nfs4_deviceid_node *node)
 292 {
 293         if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
 294                 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 295                 smp_mb__after_atomic();
 296         }
 297 }
 298 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_available);
 299
 300 void
 301 nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node)
 302 {
 303         node->timestamp_unavailable = jiffies;
 304         smp_mb__before_atomic();
 305         set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 306         smp_mb__after_atomic();
 307 }
 308 EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable);
 309
 310 bool
 311 nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node)
 312 {
 313         if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
 314                 unsigned long start, end;
 315
 316                 end = jiffies;
 317                 start = end - PNFS_DEVICE_RETRY_TIMEOUT;
 318                 if (time_in_range(node->timestamp_unavailable, start, end))
 319                         return true;
 320                 clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags);
 321                 smp_mb__after_atomic();
 322         }
 323         return false;
 324 }
 325 EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable);
 326
 327 static void
 328 _deviceid_purge_client(const struct nfs_client *clp, long hash)
 329 {
 330         struct nfs4_deviceid_node *d;
 331         HLIST_HEAD(tmp);
 332
 333         spin_lock(&nfs4_deviceid_lock);
 334         rcu_read_lock();
 335         hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node)
 336                 if (d->nfs_client == clp && atomic_read(&d->ref)) {
 337                         hlist_del_init_rcu(&d->node);
 338                         hlist_add_head(&d->tmpnode, &tmp);
 339                         clear_bit(NFS_DEVICEID_NOCACHE, &d->flags);
 340                 }
 341         rcu_read_unlock();
 342         spin_unlock(&nfs4_deviceid_lock);
 343
 344         if (hlist_empty(&tmp))
 345                 return;
 346
 347         while (!hlist_empty(&tmp)) {
 348                 d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode);
 349                 hlist_del(&d->tmpnode);
 350                 nfs4_put_deviceid_node(d);
 351         }
 352 }
 353
 354 void
 355 nfs4_deviceid_purge_client(const struct nfs_client *clp)
 356 {
 357         long h;
 358
 359         if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS))
 360                 return;
 361         for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++)
 362                 _deviceid_purge_client(clp, h);
 363 }
 364
 365 /*
 366  * Stop use of all deviceids associated with an nfs_client
 367  */
 368 void
 369 nfs4_deviceid_mark_client_invalid(struct nfs_client *clp)
 370 {
 371         struct nfs4_deviceid_node *d;
 372         int i;
 373
 374         rcu_read_lock();
 375         for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){
 376                 hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node)
 377                         if (d->nfs_client == clp)
 378                                 set_bit(NFS_DEVICEID_INVALID, &d->flags);
 379         }
 380         rcu_read_unlock();
 381 }