fs/nfs/delegation.c

   1 /*
   2  * linux/fs/nfs/delegation.c
   3  *
   4  * Copyright (C) 2004 Trond Myklebust
   5  *
   6  * NFS file delegation management
   7  *
   8  */
   9 #include <linux/completion.h>
  10 #include <linux/kthread.h>
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/spinlock.h>
  14
  15 #include <linux/nfs4.h>
  16 #include <linux/nfs_fs.h>
  17 #include <linux/nfs_xdr.h>
  18
  19 #include "nfs4_fs.h"
  20 #include "delegation.h"
  21 #include "internal.h"
  22
  23 static void nfs_do_free_delegation(struct nfs_delegation *delegation)
  24 {
  25         kfree(delegation);
  26 }
  27
  28 static void nfs_free_delegation_callback(struct rcu_head *head)
  29 {
  30         struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
  31
  32         nfs_do_free_delegation(delegation);
  33 }
  34
  35 static void nfs_free_delegation(struct nfs_delegation *delegation)
  36 {
  37         struct rpc_cred *cred;
  38
  39         cred = rcu_dereference(delegation->cred);
  40         rcu_assign_pointer(delegation->cred, NULL);
  41         call_rcu(&delegation->rcu, nfs_free_delegation_callback);
  42         if (cred)
  43                 put_rpccred(cred);
  44 }
  45
  46 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
  47 {
  48         struct inode *inode = state->inode;
  49         struct file_lock *fl;
  50         int status;
  51
  52         for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
  53                 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
  54                         continue;
  55                 if (nfs_file_open_context(fl->fl_file) != ctx)
  56                         continue;
  57                 status = nfs4_lock_delegation_recall(state, fl);
  58                 if (status >= 0)
  59                         continue;
  60                 switch (status) {
  61                         default:
  62                                 printk(KERN_ERR "%s: unhandled error %d.\n",
  63                                                 __func__, status);
  64                         case -NFS4ERR_EXPIRED:
  65                                 /* kill_proc(fl->fl_pid, SIGLOST, 1); */
  66                         case -NFS4ERR_STALE_CLIENTID:
  67                                 nfs4_schedule_state_recovery(NFS_SERVER(inode)->nfs_client);
  68                                 goto out_err;
  69                 }
  70         }
  71         return 0;
  72 out_err:
  73         return status;
  74 }
  75
  76 static void nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
  77 {
  78         struct nfs_inode *nfsi = NFS_I(inode);
  79         struct nfs_open_context *ctx;
  80         struct nfs4_state *state;
  81         int err;
  82
  83 again:
  84         spin_lock(&inode->i_lock);
  85         list_for_each_entry(ctx, &nfsi->open_files, list) {
  86                 state = ctx->state;
  87                 if (state == NULL)
  88                         continue;
  89                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
  90                         continue;
  91                 if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
  92                         continue;
  93                 get_nfs_open_context(ctx);
  94                 spin_unlock(&inode->i_lock);
  95                 err = nfs4_open_delegation_recall(ctx, state, stateid);
  96                 if (err >= 0)
  97                         err = nfs_delegation_claim_locks(ctx, state);
  98                 put_nfs_open_context(ctx);
  99                 if (err != 0)
 100                         return;
 101                 goto again;
 102         }
 103         spin_unlock(&inode->i_lock);
 104 }
 105
 106 /*
 107  * Set up a delegation on an inode
 108  */
 109 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 110 {
 111         struct nfs_delegation *delegation = NFS_I(inode)->delegation;
 112         struct rpc_cred *oldcred;
 113
 114         if (delegation == NULL)
 115                 return;
 116         memcpy(delegation->stateid.data, res->delegation.data,
 117                         sizeof(delegation->stateid.data));
 118         delegation->type = res->delegation_type;
 119         delegation->maxsize = res->maxsize;
 120         oldcred = delegation->cred;
 121         delegation->cred = get_rpccred(cred);
 122         delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
 123         NFS_I(inode)->delegation_state = delegation->type;
 124         smp_wmb();
 125         put_rpccred(oldcred);
 126 }
 127
 128 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 129 {
 130         int res = 0;
 131
 132         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
 133         nfs_free_delegation(delegation);
 134         return res;
 135 }
 136
 137 static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
 138 {
 139         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 140
 141         if (delegation == NULL)
 142                 goto nomatch;
 143         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 144                                 sizeof(delegation->stateid.data)) != 0)
 145                 goto nomatch;
 146         list_del_rcu(&delegation->super_list);
 147         nfsi->delegation_state = 0;
 148         rcu_assign_pointer(nfsi->delegation, NULL);
 149         return delegation;
 150 nomatch:
 151         return NULL;
 152 }
 153
 154 /*
 155  * Set up a delegation on an inode
 156  */
 157 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 158 {
 159         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 160         struct nfs_inode *nfsi = NFS_I(inode);
 161         struct nfs_delegation *delegation;
 162         struct nfs_delegation *freeme = NULL;
 163         int status = 0;
 164
 165         delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
 166         if (delegation == NULL)
 167                 return -ENOMEM;
 168         memcpy(delegation->stateid.data, res->delegation.data,
 169                         sizeof(delegation->stateid.data));
 170         delegation->type = res->delegation_type;
 171         delegation->maxsize = res->maxsize;
 172         delegation->change_attr = nfsi->change_attr;
 173         delegation->cred = get_rpccred(cred);
 174         delegation->inode = inode;
 175
 176         spin_lock(&clp->cl_lock);
 177         if (rcu_dereference(nfsi->delegation) != NULL) {
 178                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
 179                                         sizeof(delegation->stateid)) == 0 &&
 180                                 delegation->type == nfsi->delegation->type) {
 181                         goto out;
 182                 }
 183                 /*
 184                  * Deal with broken servers that hand out two
 185                  * delegations for the same file.
 186                  */
 187                 dfprintk(FILE, "%s: server %s handed out "
 188                                 "a duplicate delegation!\n",
 189                                 __func__, clp->cl_hostname);
 190                 if (delegation->type <= nfsi->delegation->type) {
 191                         freeme = delegation;
 192                         delegation = NULL;
 193                         goto out;
 194                 }
 195                 freeme = nfs_detach_delegation_locked(nfsi, NULL);
 196         }
 197         list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 198         nfsi->delegation_state = delegation->type;
 199         rcu_assign_pointer(nfsi->delegation, delegation);
 200         delegation = NULL;
 201
 202         /* Ensure we revalidate the attributes and page cache! */
 203         spin_lock(&inode->i_lock);
 204         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 205         spin_unlock(&inode->i_lock);
 206
 207 out:
 208         spin_unlock(&clp->cl_lock);
 209         if (delegation != NULL)
 210                 nfs_free_delegation(delegation);
 211         if (freeme != NULL)
 212                 nfs_do_return_delegation(inode, freeme, 0);
 213         return status;
 214 }
 215
 216 /* Sync all data to disk upon delegation return */
 217 static void nfs_msync_inode(struct inode *inode)
 218 {
 219         filemap_fdatawrite(inode->i_mapping);
 220         nfs_wb_all(inode);
 221         filemap_fdatawait(inode->i_mapping);
 222 }
 223
 224 /*
 225  * Basic procedure for returning a delegation to the server
 226  */
 227 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 228 {
 229         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 230         struct nfs_inode *nfsi = NFS_I(inode);
 231
 232         nfs_msync_inode(inode);
 233         down_read(&clp->cl_sem);
 234         /* Guard against new delegated open calls */
 235         down_write(&nfsi->rwsem);
 236         nfs_delegation_claim_opens(inode, &delegation->stateid);
 237         up_write(&nfsi->rwsem);
 238         up_read(&clp->cl_sem);
 239         nfs_msync_inode(inode);
 240
 241         return nfs_do_return_delegation(inode, delegation, 1);
 242 }
 243
 244 /*
 245  * This function returns the delegation without reclaiming opens
 246  * or protecting against delegation reclaims.
 247  * It is therefore really only safe to be called from
 248  * nfs4_clear_inode()
 249  */
 250 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 251 {
 252         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 253         struct nfs_inode *nfsi = NFS_I(inode);
 254         struct nfs_delegation *delegation;
 255
 256         if (rcu_dereference(nfsi->delegation) != NULL) {
 257                 spin_lock(&clp->cl_lock);
 258                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 259                 spin_unlock(&clp->cl_lock);
 260                 if (delegation != NULL)
 261                         nfs_do_return_delegation(inode, delegation, 0);
 262         }
 263 }
 264
 265 int nfs_inode_return_delegation(struct inode *inode)
 266 {
 267         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 268         struct nfs_inode *nfsi = NFS_I(inode);
 269         struct nfs_delegation *delegation;
 270         int err = 0;
 271
 272         if (rcu_dereference(nfsi->delegation) != NULL) {
 273                 spin_lock(&clp->cl_lock);
 274                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 275                 spin_unlock(&clp->cl_lock);
 276                 if (delegation != NULL)
 277                         err = __nfs_inode_return_delegation(inode, delegation);
 278         }
 279         return err;
 280 }
 281
 282 /*
 283  * Return all delegations associated to a super block
 284  */
 285 void nfs_return_all_delegations(struct super_block *sb)
 286 {
 287         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 288         struct nfs_delegation *delegation;
 289         struct inode *inode;
 290
 291         if (clp == NULL)
 292                 return;
 293 restart:
 294         rcu_read_lock();
 295         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 296                 if (delegation->inode->i_sb != sb)
 297                         continue;
 298                 inode = igrab(delegation->inode);
 299                 if (inode == NULL)
 300                         continue;
 301                 spin_lock(&clp->cl_lock);
 302                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 303                 spin_unlock(&clp->cl_lock);
 304                 rcu_read_unlock();
 305                 if (delegation != NULL)
 306                         __nfs_inode_return_delegation(inode, delegation);
 307                 iput(inode);
 308                 goto restart;
 309         }
 310         rcu_read_unlock();
 311 }
 312
 313 static int nfs_do_expire_all_delegations(void *ptr)
 314 {
 315         struct nfs_client *clp = ptr;
 316         struct nfs_delegation *delegation;
 317         struct inode *inode;
 318
 319         allow_signal(SIGKILL);
 320 restart:
 321         if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
 322                 goto out;
 323         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
 324                 goto out;
 325         rcu_read_lock();
 326         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 327                 inode = igrab(delegation->inode);
 328                 if (inode == NULL)
 329                         continue;
 330                 spin_lock(&clp->cl_lock);
 331                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 332                 spin_unlock(&clp->cl_lock);
 333                 rcu_read_unlock();
 334                 if (delegation)
 335                         __nfs_inode_return_delegation(inode, delegation);
 336                 iput(inode);
 337                 goto restart;
 338         }
 339         rcu_read_unlock();
 340 out:
 341         nfs_put_client(clp);
 342         module_put_and_exit(0);
 343 }
 344
 345 void nfs_expire_all_delegations(struct nfs_client *clp)
 346 {
 347         struct task_struct *task;
 348
 349         __module_get(THIS_MODULE);
 350         atomic_inc(&clp->cl_count);
 351         task = kthread_run(nfs_do_expire_all_delegations, clp,
 352                                 "%s-delegreturn",
 353                                 rpc_peeraddr2str(clp->cl_rpcclient,
 354                                                         RPC_DISPLAY_ADDR));
 355         if (!IS_ERR(task))
 356                 return;
 357         nfs_put_client(clp);
 358         module_put(THIS_MODULE);
 359 }
 360
 361 /*
 362  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 363  */
 364 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 365 {
 366         struct nfs_delegation *delegation;
 367         struct inode *inode;
 368
 369         if (clp == NULL)
 370                 return;
 371 restart:
 372         rcu_read_lock();
 373         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 374                 inode = igrab(delegation->inode);
 375                 if (inode == NULL)
 376                         continue;
 377                 spin_lock(&clp->cl_lock);
 378                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 379                 spin_unlock(&clp->cl_lock);
 380                 rcu_read_unlock();
 381                 if (delegation != NULL)
 382                         __nfs_inode_return_delegation(inode, delegation);
 383                 iput(inode);
 384                 goto restart;
 385         }
 386         rcu_read_unlock();
 387 }
 388
 389 struct recall_threadargs {
 390         struct inode *inode;
 391         struct nfs_client *clp;
 392         const nfs4_stateid *stateid;
 393
 394         struct completion started;
 395         int result;
 396 };
 397
 398 static int recall_thread(void *data)
 399 {
 400         struct recall_threadargs *args = (struct recall_threadargs *)data;
 401         struct inode *inode = igrab(args->inode);
 402         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 403         struct nfs_inode *nfsi = NFS_I(inode);
 404         struct nfs_delegation *delegation;
 405
 406         daemonize("nfsv4-delegreturn");
 407
 408         nfs_msync_inode(inode);
 409         down_read(&clp->cl_sem);
 410         down_write(&nfsi->rwsem);
 411         spin_lock(&clp->cl_lock);
 412         delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
 413         if (delegation != NULL)
 414                 args->result = 0;
 415         else
 416                 args->result = -ENOENT;
 417         spin_unlock(&clp->cl_lock);
 418         complete(&args->started);
 419         nfs_delegation_claim_opens(inode, args->stateid);
 420         up_write(&nfsi->rwsem);
 421         up_read(&clp->cl_sem);
 422         nfs_msync_inode(inode);
 423
 424         if (delegation != NULL)
 425                 nfs_do_return_delegation(inode, delegation, 1);
 426         iput(inode);
 427         module_put_and_exit(0);
 428 }
 429
 430 /*
 431  * Asynchronous delegation recall!
 432  */
 433 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 434 {
 435         struct recall_threadargs data = {
 436                 .inode = inode,
 437                 .stateid = stateid,
 438         };
 439         int status;
 440
 441         init_completion(&data.started);
 442         __module_get(THIS_MODULE);
 443         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 444         if (status < 0)
 445                 goto out_module_put;
 446         wait_for_completion(&data.started);
 447         return data.result;
 448 out_module_put:
 449         module_put(THIS_MODULE);
 450         return status;
 451 }
 452
 453 /*
 454  * Retrieve the inode associated with a delegation
 455  */
 456 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 457 {
 458         struct nfs_delegation *delegation;
 459         struct inode *res = NULL;
 460         rcu_read_lock();
 461         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 462                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 463                         res = igrab(delegation->inode);
 464                         break;
 465                 }
 466         }
 467         rcu_read_unlock();
 468         return res;
 469 }
 470
 471 /*
 472  * Mark all delegations as needing to be reclaimed
 473  */
 474 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 475 {
 476         struct nfs_delegation *delegation;
 477         rcu_read_lock();
 478         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 479                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
 480         rcu_read_unlock();
 481 }
 482
 483 /*
 484  * Reap all unclaimed delegations after reboot recovery is done
 485  */
 486 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 487 {
 488         struct nfs_delegation *delegation;
 489 restart:
 490         rcu_read_lock();
 491         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 492                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
 493                         continue;
 494                 spin_lock(&clp->cl_lock);
 495                 delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
 496                 spin_unlock(&clp->cl_lock);
 497                 rcu_read_unlock();
 498                 if (delegation != NULL)
 499                         nfs_free_delegation(delegation);
 500                 goto restart;
 501         }
 502         rcu_read_unlock();
 503 }
 504
 505 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 506 {
 507         struct nfs_inode *nfsi = NFS_I(inode);
 508         struct nfs_delegation *delegation;
 509         int ret = 0;
 510
 511         rcu_read_lock();
 512         delegation = rcu_dereference(nfsi->delegation);
 513         if (delegation != NULL) {
 514                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 515                 ret = 1;
 516         }
 517         rcu_read_unlock();
 518         return ret;
 519 }