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   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         clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 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 inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 138 {
 139         struct inode *inode = NULL;
 140
 141         spin_lock(&delegation->lock);
 142         if (delegation->inode != NULL)
 143                 inode = igrab(delegation->inode);
 144         spin_unlock(&delegation->lock);
 145         return inode;
 146 }
 147
 148 static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
 149 {
 150         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 151
 152         if (delegation == NULL)
 153                 goto nomatch;
 154         spin_lock(&delegation->lock);
 155         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 156                                 sizeof(delegation->stateid.data)) != 0)
 157                 goto nomatch_unlock;
 158         list_del_rcu(&delegation->super_list);
 159         delegation->inode = NULL;
 160         nfsi->delegation_state = 0;
 161         rcu_assign_pointer(nfsi->delegation, NULL);
 162         spin_unlock(&delegation->lock);
 163         return delegation;
 164 nomatch_unlock:
 165         spin_unlock(&delegation->lock);
 166 nomatch:
 167         return NULL;
 168 }
 169
 170 /*
 171  * Set up a delegation on an inode
 172  */
 173 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 174 {
 175         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 176         struct nfs_inode *nfsi = NFS_I(inode);
 177         struct nfs_delegation *delegation;
 178         struct nfs_delegation *freeme = NULL;
 179         int status = 0;
 180
 181         delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
 182         if (delegation == NULL)
 183                 return -ENOMEM;
 184         memcpy(delegation->stateid.data, res->delegation.data,
 185                         sizeof(delegation->stateid.data));
 186         delegation->type = res->delegation_type;
 187         delegation->maxsize = res->maxsize;
 188         delegation->change_attr = nfsi->change_attr;
 189         delegation->cred = get_rpccred(cred);
 190         delegation->inode = inode;
 191         spin_lock_init(&delegation->lock);
 192
 193         spin_lock(&clp->cl_lock);
 194         if (rcu_dereference(nfsi->delegation) != NULL) {
 195                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
 196                                         sizeof(delegation->stateid)) == 0 &&
 197                                 delegation->type == nfsi->delegation->type) {
 198                         goto out;
 199                 }
 200                 /*
 201                  * Deal with broken servers that hand out two
 202                  * delegations for the same file.
 203                  */
 204                 dfprintk(FILE, "%s: server %s handed out "
 205                                 "a duplicate delegation!\n",
 206                                 __func__, clp->cl_hostname);
 207                 if (delegation->type <= nfsi->delegation->type) {
 208                         freeme = delegation;
 209                         delegation = NULL;
 210                         goto out;
 211                 }
 212                 freeme = nfs_detach_delegation_locked(nfsi, NULL);
 213         }
 214         list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 215         nfsi->delegation_state = delegation->type;
 216         rcu_assign_pointer(nfsi->delegation, delegation);
 217         delegation = NULL;
 218
 219         /* Ensure we revalidate the attributes and page cache! */
 220         spin_lock(&inode->i_lock);
 221         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 222         spin_unlock(&inode->i_lock);
 223
 224 out:
 225         spin_unlock(&clp->cl_lock);
 226         if (delegation != NULL)
 227                 nfs_free_delegation(delegation);
 228         if (freeme != NULL)
 229                 nfs_do_return_delegation(inode, freeme, 0);
 230         return status;
 231 }
 232
 233 /* Sync all data to disk upon delegation return */
 234 static void nfs_msync_inode(struct inode *inode)
 235 {
 236         filemap_fdatawrite(inode->i_mapping);
 237         nfs_wb_all(inode);
 238         filemap_fdatawait(inode->i_mapping);
 239 }
 240
 241 /*
 242  * Basic procedure for returning a delegation to the server
 243  */
 244 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 245 {
 246         struct nfs_inode *nfsi = NFS_I(inode);
 247
 248         nfs_msync_inode(inode);
 249         /* Guard against new delegated open calls */
 250         down_write(&nfsi->rwsem);
 251         nfs_delegation_claim_opens(inode, &delegation->stateid);
 252         up_write(&nfsi->rwsem);
 253         nfs_msync_inode(inode);
 254
 255         return nfs_do_return_delegation(inode, delegation, 1);
 256 }
 257
 258 /*
 259  * This function returns the delegation without reclaiming opens
 260  * or protecting against delegation reclaims.
 261  * It is therefore really only safe to be called from
 262  * nfs4_clear_inode()
 263  */
 264 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 265 {
 266         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 267         struct nfs_inode *nfsi = NFS_I(inode);
 268         struct nfs_delegation *delegation;
 269
 270         if (rcu_dereference(nfsi->delegation) != NULL) {
 271                 spin_lock(&clp->cl_lock);
 272                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 273                 spin_unlock(&clp->cl_lock);
 274                 if (delegation != NULL)
 275                         nfs_do_return_delegation(inode, delegation, 0);
 276         }
 277 }
 278
 279 int nfs_inode_return_delegation(struct inode *inode)
 280 {
 281         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 282         struct nfs_inode *nfsi = NFS_I(inode);
 283         struct nfs_delegation *delegation;
 284         int err = 0;
 285
 286         if (rcu_dereference(nfsi->delegation) != NULL) {
 287                 spin_lock(&clp->cl_lock);
 288                 delegation = nfs_detach_delegation_locked(nfsi, NULL);
 289                 spin_unlock(&clp->cl_lock);
 290                 if (delegation != NULL)
 291                         err = __nfs_inode_return_delegation(inode, delegation);
 292         }
 293         return err;
 294 }
 295
 296 /*
 297  * Return all delegations associated to a super block
 298  */
 299 void nfs_return_all_delegations(struct super_block *sb)
 300 {
 301         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 302         struct nfs_delegation *delegation;
 303         struct inode *inode;
 304
 305         if (clp == NULL)
 306                 return;
 307 restart:
 308         rcu_read_lock();
 309         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 310                 inode = NULL;
 311                 spin_lock(&delegation->lock);
 312                 if (delegation->inode != NULL && delegation->inode->i_sb == sb)
 313                         inode = igrab(delegation->inode);
 314                 spin_unlock(&delegation->lock);
 315                 if (inode == NULL)
 316                         continue;
 317                 spin_lock(&clp->cl_lock);
 318                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 319                 spin_unlock(&clp->cl_lock);
 320                 rcu_read_unlock();
 321                 if (delegation != NULL)
 322                         __nfs_inode_return_delegation(inode, delegation);
 323                 iput(inode);
 324                 goto restart;
 325         }
 326         rcu_read_unlock();
 327 }
 328
 329 static int nfs_do_expire_all_delegations(void *ptr)
 330 {
 331         struct nfs_client *clp = ptr;
 332         struct nfs_delegation *delegation;
 333         struct inode *inode;
 334
 335         allow_signal(SIGKILL);
 336 restart:
 337         if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
 338                 goto out;
 339         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
 340                 goto out;
 341         rcu_read_lock();
 342         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 343                 inode = nfs_delegation_grab_inode(delegation);
 344                 if (inode == NULL)
 345                         continue;
 346                 spin_lock(&clp->cl_lock);
 347                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 348                 spin_unlock(&clp->cl_lock);
 349                 rcu_read_unlock();
 350                 if (delegation)
 351                         __nfs_inode_return_delegation(inode, delegation);
 352                 iput(inode);
 353                 goto restart;
 354         }
 355         rcu_read_unlock();
 356 out:
 357         nfs_put_client(clp);
 358         module_put_and_exit(0);
 359 }
 360
 361 void nfs_expire_all_delegations(struct nfs_client *clp)
 362 {
 363         struct task_struct *task;
 364
 365         __module_get(THIS_MODULE);
 366         atomic_inc(&clp->cl_count);
 367         task = kthread_run(nfs_do_expire_all_delegations, clp,
 368                                 "%s-delegreturn",
 369                                 rpc_peeraddr2str(clp->cl_rpcclient,
 370                                                         RPC_DISPLAY_ADDR));
 371         if (!IS_ERR(task))
 372                 return;
 373         nfs_put_client(clp);
 374         module_put(THIS_MODULE);
 375 }
 376
 377 /*
 378  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 379  */
 380 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 381 {
 382         struct nfs_delegation *delegation;
 383         struct inode *inode;
 384
 385         if (clp == NULL)
 386                 return;
 387 restart:
 388         rcu_read_lock();
 389         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 390                 inode = nfs_delegation_grab_inode(delegation);
 391                 if (inode == NULL)
 392                         continue;
 393                 spin_lock(&clp->cl_lock);
 394                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 395                 spin_unlock(&clp->cl_lock);
 396                 rcu_read_unlock();
 397                 if (delegation != NULL)
 398                         __nfs_inode_return_delegation(inode, delegation);
 399                 iput(inode);
 400                 goto restart;
 401         }
 402         rcu_read_unlock();
 403 }
 404
 405 struct recall_threadargs {
 406         struct inode *inode;
 407         struct nfs_client *clp;
 408         const nfs4_stateid *stateid;
 409
 410         struct completion started;
 411         int result;
 412 };
 413
 414 static int recall_thread(void *data)
 415 {
 416         struct recall_threadargs *args = (struct recall_threadargs *)data;
 417         struct inode *inode = igrab(args->inode);
 418         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 419         struct nfs_inode *nfsi = NFS_I(inode);
 420         struct nfs_delegation *delegation;
 421
 422         daemonize("nfsv4-delegreturn");
 423
 424         nfs_msync_inode(inode);
 425         down_write(&nfsi->rwsem);
 426         spin_lock(&clp->cl_lock);
 427         delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
 428         if (delegation != NULL)
 429                 args->result = 0;
 430         else
 431                 args->result = -ENOENT;
 432         spin_unlock(&clp->cl_lock);
 433         complete(&args->started);
 434         nfs_delegation_claim_opens(inode, args->stateid);
 435         up_write(&nfsi->rwsem);
 436         nfs_msync_inode(inode);
 437
 438         if (delegation != NULL)
 439                 nfs_do_return_delegation(inode, delegation, 1);
 440         iput(inode);
 441         module_put_and_exit(0);
 442 }
 443
 444 /*
 445  * Asynchronous delegation recall!
 446  */
 447 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 448 {
 449         struct recall_threadargs data = {
 450                 .inode = inode,
 451                 .stateid = stateid,
 452         };
 453         int status;
 454
 455         init_completion(&data.started);
 456         __module_get(THIS_MODULE);
 457         status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
 458         if (status < 0)
 459                 goto out_module_put;
 460         wait_for_completion(&data.started);
 461         return data.result;
 462 out_module_put:
 463         module_put(THIS_MODULE);
 464         return status;
 465 }
 466
 467 /*
 468  * Retrieve the inode associated with a delegation
 469  */
 470 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 471 {
 472         struct nfs_delegation *delegation;
 473         struct inode *res = NULL;
 474         rcu_read_lock();
 475         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 476                 spin_lock(&delegation->lock);
 477                 if (delegation->inode != NULL &&
 478                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 479                         res = igrab(delegation->inode);
 480                 }
 481                 spin_unlock(&delegation->lock);
 482                 if (res != NULL)
 483                         break;
 484         }
 485         rcu_read_unlock();
 486         return res;
 487 }
 488
 489 /*
 490  * Mark all delegations as needing to be reclaimed
 491  */
 492 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 493 {
 494         struct nfs_delegation *delegation;
 495         rcu_read_lock();
 496         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 497                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 498         rcu_read_unlock();
 499 }
 500
 501 /*
 502  * Reap all unclaimed delegations after reboot recovery is done
 503  */
 504 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 505 {
 506         struct nfs_delegation *delegation;
 507         struct inode *inode;
 508 restart:
 509         rcu_read_lock();
 510         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 511                 if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
 512                         continue;
 513                 inode = nfs_delegation_grab_inode(delegation);
 514                 if (inode == NULL)
 515                         continue;
 516                 spin_lock(&clp->cl_lock);
 517                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 518                 spin_unlock(&clp->cl_lock);
 519                 rcu_read_unlock();
 520                 if (delegation != NULL)
 521                         nfs_free_delegation(delegation);
 522                 iput(inode);
 523                 goto restart;
 524         }
 525         rcu_read_unlock();
 526 }
 527
 528 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 529 {
 530         struct nfs_inode *nfsi = NFS_I(inode);
 531         struct nfs_delegation *delegation;
 532         int ret = 0;
 533
 534         rcu_read_lock();
 535         delegation = rcu_dereference(nfsi->delegation);
 536         if (delegation != NULL) {
 537                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 538                 ret = 1;
 539         }
 540         rcu_read_unlock();
 541         return ret;
 542 }