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/slab.h>
  14 #include <linux/spinlock.h>
  15
  16 #include <linux/nfs4.h>
  17 #include <linux/nfs_fs.h>
  18 #include <linux/nfs_xdr.h>
  19
  20 #include "nfs4_fs.h"
  21 #include "delegation.h"
  22 #include "internal.h"
  23
  24 static void nfs_do_free_delegation(struct nfs_delegation *delegation)
  25 {
  26         if (delegation->cred)
  27                 put_rpccred(delegation->cred);
  28         kfree(delegation);
  29 }
  30
  31 static void nfs_free_delegation_callback(struct rcu_head *head)
  32 {
  33         struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
  34
  35         nfs_do_free_delegation(delegation);
  36 }
  37
  38 static void nfs_free_delegation(struct nfs_delegation *delegation)
  39 {
  40         call_rcu(&delegation->rcu, nfs_free_delegation_callback);
  41 }
  42
  43 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  44 {
  45         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  46 }
  47
  48 int nfs_have_delegation(struct inode *inode, fmode_t flags)
  49 {
  50         struct nfs_delegation *delegation;
  51         int ret = 0;
  52
  53         flags &= FMODE_READ|FMODE_WRITE;
  54         rcu_read_lock();
  55         delegation = rcu_dereference(NFS_I(inode)->delegation);
  56         if (delegation != NULL && (delegation->type & flags) == flags) {
  57                 nfs_mark_delegation_referenced(delegation);
  58                 ret = 1;
  59         }
  60         rcu_read_unlock();
  61         return ret;
  62 }
  63
  64 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
  65 {
  66         struct inode *inode = state->inode;
  67         struct file_lock *fl;
  68         int status = 0;
  69
  70         if (inode->i_flock == NULL)
  71                 goto out;
  72
  73         /* Protect inode->i_flock using the file locks lock */
  74         lock_flocks();
  75         for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
  76                 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
  77                         continue;
  78                 if (nfs_file_open_context(fl->fl_file) != ctx)
  79                         continue;
  80                 unlock_flocks();
  81                 status = nfs4_lock_delegation_recall(state, fl);
  82                 if (status < 0)
  83                         goto out;
  84                 lock_flocks();
  85         }
  86         unlock_flocks();
  87 out:
  88         return status;
  89 }
  90
  91 static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
  92 {
  93         struct nfs_inode *nfsi = NFS_I(inode);
  94         struct nfs_open_context *ctx;
  95         struct nfs4_state *state;
  96         int err;
  97
  98 again:
  99         spin_lock(&inode->i_lock);
 100         list_for_each_entry(ctx, &nfsi->open_files, list) {
 101                 state = ctx->state;
 102                 if (state == NULL)
 103                         continue;
 104                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 105                         continue;
 106                 if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
 107                         continue;
 108                 get_nfs_open_context(ctx);
 109                 spin_unlock(&inode->i_lock);
 110                 err = nfs4_open_delegation_recall(ctx, state, stateid);
 111                 if (err >= 0)
 112                         err = nfs_delegation_claim_locks(ctx, state);
 113                 put_nfs_open_context(ctx);
 114                 if (err != 0)
 115                         return err;
 116                 goto again;
 117         }
 118         spin_unlock(&inode->i_lock);
 119         return 0;
 120 }
 121
 122 /*
 123  * Set up a delegation on an inode
 124  */
 125 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 126 {
 127         struct nfs_delegation *delegation;
 128         struct rpc_cred *oldcred = NULL;
 129
 130         rcu_read_lock();
 131         delegation = rcu_dereference(NFS_I(inode)->delegation);
 132         if (delegation != NULL) {
 133                 spin_lock(&delegation->lock);
 134                 if (delegation->inode != NULL) {
 135                         memcpy(delegation->stateid.data, res->delegation.data,
 136                                sizeof(delegation->stateid.data));
 137                         delegation->type = res->delegation_type;
 138                         delegation->maxsize = res->maxsize;
 139                         oldcred = delegation->cred;
 140                         delegation->cred = get_rpccred(cred);
 141                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 142                                   &delegation->flags);
 143                         NFS_I(inode)->delegation_state = delegation->type;
 144                         spin_unlock(&delegation->lock);
 145                         put_rpccred(oldcred);
 146                         rcu_read_unlock();
 147                 } else {
 148                         /* We appear to have raced with a delegation return. */
 149                         spin_unlock(&delegation->lock);
 150                         rcu_read_unlock();
 151                         nfs_inode_set_delegation(inode, cred, res);
 152                 }
 153         } else {
 154                 rcu_read_unlock();
 155         }
 156 }
 157
 158 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 159 {
 160         int res = 0;
 161
 162         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
 163         nfs_free_delegation(delegation);
 164         return res;
 165 }
 166
 167 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 168 {
 169         struct inode *inode = NULL;
 170
 171         spin_lock(&delegation->lock);
 172         if (delegation->inode != NULL)
 173                 inode = igrab(delegation->inode);
 174         spin_unlock(&delegation->lock);
 175         return inode;
 176 }
 177
 178 static struct nfs_delegation *
 179 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 180                              struct nfs_client *clp)
 181 {
 182         struct nfs_delegation *delegation =
 183                 rcu_dereference_protected(nfsi->delegation,
 184                                           lockdep_is_held(&clp->cl_lock));
 185
 186         if (delegation == NULL)
 187                 goto nomatch;
 188
 189         spin_lock(&delegation->lock);
 190         list_del_rcu(&delegation->super_list);
 191         delegation->inode = NULL;
 192         nfsi->delegation_state = 0;
 193         rcu_assign_pointer(nfsi->delegation, NULL);
 194         spin_unlock(&delegation->lock);
 195         return delegation;
 196 nomatch:
 197         return NULL;
 198 }
 199
 200 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 201                                                     struct nfs_client *clp)
 202 {
 203         struct nfs_delegation *delegation;
 204
 205         spin_lock(&clp->cl_lock);
 206         delegation = nfs_detach_delegation_locked(nfsi, clp);
 207         spin_unlock(&clp->cl_lock);
 208         return delegation;
 209 }
 210
 211 /*
 212  * Set up a delegation on an inode
 213  */
 214 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 215 {
 216         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 217         struct nfs_inode *nfsi = NFS_I(inode);
 218         struct nfs_delegation *delegation, *old_delegation;
 219         struct nfs_delegation *freeme = NULL;
 220         int status = 0;
 221
 222         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 223         if (delegation == NULL)
 224                 return -ENOMEM;
 225         memcpy(delegation->stateid.data, res->delegation.data,
 226                         sizeof(delegation->stateid.data));
 227         delegation->type = res->delegation_type;
 228         delegation->maxsize = res->maxsize;
 229         delegation->change_attr = nfsi->change_attr;
 230         delegation->cred = get_rpccred(cred);
 231         delegation->inode = inode;
 232         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 233         spin_lock_init(&delegation->lock);
 234
 235         spin_lock(&clp->cl_lock);
 236         old_delegation = rcu_dereference_protected(nfsi->delegation,
 237                                                    lockdep_is_held(&clp->cl_lock));
 238         if (old_delegation != NULL) {
 239                 if (memcmp(&delegation->stateid, &old_delegation->stateid,
 240                                         sizeof(old_delegation->stateid)) == 0 &&
 241                                 delegation->type == old_delegation->type) {
 242                         goto out;
 243                 }
 244                 /*
 245                  * Deal with broken servers that hand out two
 246                  * delegations for the same file.
 247                  */
 248                 dfprintk(FILE, "%s: server %s handed out "
 249                                 "a duplicate delegation!\n",
 250                                 __func__, clp->cl_hostname);
 251                 if (delegation->type <= old_delegation->type) {
 252                         freeme = delegation;
 253                         delegation = NULL;
 254                         goto out;
 255                 }
 256                 freeme = nfs_detach_delegation_locked(nfsi, clp);
 257         }
 258         list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 259         nfsi->delegation_state = delegation->type;
 260         rcu_assign_pointer(nfsi->delegation, delegation);
 261         delegation = NULL;
 262
 263         /* Ensure we revalidate the attributes and page cache! */
 264         spin_lock(&inode->i_lock);
 265         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 266         spin_unlock(&inode->i_lock);
 267
 268 out:
 269         spin_unlock(&clp->cl_lock);
 270         if (delegation != NULL)
 271                 nfs_free_delegation(delegation);
 272         if (freeme != NULL)
 273                 nfs_do_return_delegation(inode, freeme, 0);
 274         return status;
 275 }
 276
 277 /*
 278  * Basic procedure for returning a delegation to the server
 279  */
 280 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 281 {
 282         struct nfs_inode *nfsi = NFS_I(inode);
 283         int err;
 284
 285         /*
 286          * Guard against new delegated open/lock/unlock calls and against
 287          * state recovery
 288          */
 289         down_write(&nfsi->rwsem);
 290         err = nfs_delegation_claim_opens(inode, &delegation->stateid);
 291         up_write(&nfsi->rwsem);
 292         if (err)
 293                 goto out;
 294
 295         err = nfs_do_return_delegation(inode, delegation, issync);
 296 out:
 297         return err;
 298 }
 299
 300 /*
 301  * Return all delegations that have been marked for return
 302  */
 303 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 304 {
 305         struct nfs_delegation *delegation;
 306         struct inode *inode;
 307         int err = 0;
 308
 309 restart:
 310         rcu_read_lock();
 311         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 312                 if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 313                         continue;
 314                 inode = nfs_delegation_grab_inode(delegation);
 315                 if (inode == NULL)
 316                         continue;
 317                 delegation = nfs_detach_delegation(NFS_I(inode), clp);
 318                 rcu_read_unlock();
 319                 if (delegation != NULL) {
 320                         filemap_flush(inode->i_mapping);
 321                         err = __nfs_inode_return_delegation(inode, delegation, 0);
 322                 }
 323                 iput(inode);
 324                 if (!err)
 325                         goto restart;
 326                 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 327                 return err;
 328         }
 329         rcu_read_unlock();
 330         return 0;
 331 }
 332
 333 /*
 334  * This function returns the delegation without reclaiming opens
 335  * or protecting against delegation reclaims.
 336  * It is therefore really only safe to be called from
 337  * nfs4_clear_inode()
 338  */
 339 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 340 {
 341         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 342         struct nfs_inode *nfsi = NFS_I(inode);
 343         struct nfs_delegation *delegation;
 344
 345         if (rcu_access_pointer(nfsi->delegation) != NULL) {
 346                 delegation = nfs_detach_delegation(nfsi, clp);
 347                 if (delegation != NULL)
 348                         nfs_do_return_delegation(inode, delegation, 0);
 349         }
 350 }
 351
 352 int nfs_inode_return_delegation(struct inode *inode)
 353 {
 354         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 355         struct nfs_inode *nfsi = NFS_I(inode);
 356         struct nfs_delegation *delegation;
 357         int err = 0;
 358
 359         if (rcu_access_pointer(nfsi->delegation) != NULL) {
 360                 delegation = nfs_detach_delegation(nfsi, clp);
 361                 if (delegation != NULL) {
 362                         nfs_wb_all(inode);
 363                         err = __nfs_inode_return_delegation(inode, delegation, 1);
 364                 }
 365         }
 366         return err;
 367 }
 368
 369 static void nfs_mark_return_delegation(struct nfs_client *clp, struct nfs_delegation *delegation)
 370 {
 371         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 372         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 373 }
 374
 375 /*
 376  * Return all delegations associated to a super block
 377  */
 378 void nfs_super_return_all_delegations(struct super_block *sb)
 379 {
 380         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 381         struct nfs_delegation *delegation;
 382
 383         if (clp == NULL)
 384                 return;
 385         rcu_read_lock();
 386         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 387                 spin_lock(&delegation->lock);
 388                 if (delegation->inode != NULL && delegation->inode->i_sb == sb)
 389                         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 390                 spin_unlock(&delegation->lock);
 391         }
 392         rcu_read_unlock();
 393         if (nfs_client_return_marked_delegations(clp) != 0)
 394                 nfs4_schedule_state_manager(clp);
 395 }
 396
 397 static
 398 void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp, fmode_t flags)
 399 {
 400         struct nfs_delegation *delegation;
 401
 402         rcu_read_lock();
 403         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 404                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 405                         continue;
 406                 if (delegation->type & flags)
 407                         nfs_mark_return_delegation(clp, delegation);
 408         }
 409         rcu_read_unlock();
 410 }
 411
 412 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 413 {
 414         nfs_client_mark_return_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
 415 }
 416
 417 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 418 {
 419         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 420                 nfs4_schedule_state_manager(clp);
 421 }
 422
 423 void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags)
 424 {
 425         nfs_client_mark_return_all_delegation_types(clp, flags);
 426         nfs_delegation_run_state_manager(clp);
 427 }
 428
 429 void nfs_expire_all_delegations(struct nfs_client *clp)
 430 {
 431         nfs_expire_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
 432 }
 433
 434 /*
 435  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 436  */
 437 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 438 {
 439         if (clp == NULL)
 440                 return;
 441         nfs_client_mark_return_all_delegations(clp);
 442 }
 443
 444 static void nfs_client_mark_return_unreferenced_delegations(struct nfs_client *clp)
 445 {
 446         struct nfs_delegation *delegation;
 447
 448         rcu_read_lock();
 449         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 450                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 451                         continue;
 452                 nfs_mark_return_delegation(clp, delegation);
 453         }
 454         rcu_read_unlock();
 455 }
 456
 457 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 458 {
 459         nfs_client_mark_return_unreferenced_delegations(clp);
 460         nfs_delegation_run_state_manager(clp);
 461 }
 462
 463 /*
 464  * Asynchronous delegation recall!
 465  */
 466 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 467 {
 468         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 469         struct nfs_delegation *delegation;
 470
 471         rcu_read_lock();
 472         delegation = rcu_dereference(NFS_I(inode)->delegation);
 473
 474         if (!clp->cl_mvops->validate_stateid(delegation, stateid)) {
 475                 rcu_read_unlock();
 476                 return -ENOENT;
 477         }
 478
 479         nfs_mark_return_delegation(clp, delegation);
 480         rcu_read_unlock();
 481         nfs_delegation_run_state_manager(clp);
 482         return 0;
 483 }
 484
 485 /*
 486  * Retrieve the inode associated with a delegation
 487  */
 488 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 489 {
 490         struct nfs_delegation *delegation;
 491         struct inode *res = NULL;
 492         rcu_read_lock();
 493         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 494                 spin_lock(&delegation->lock);
 495                 if (delegation->inode != NULL &&
 496                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 497                         res = igrab(delegation->inode);
 498                 }
 499                 spin_unlock(&delegation->lock);
 500                 if (res != NULL)
 501                         break;
 502         }
 503         rcu_read_unlock();
 504         return res;
 505 }
 506
 507 /*
 508  * Mark all delegations as needing to be reclaimed
 509  */
 510 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 511 {
 512         struct nfs_delegation *delegation;
 513         rcu_read_lock();
 514         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 515                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 516         rcu_read_unlock();
 517 }
 518
 519 /*
 520  * Reap all unclaimed delegations after reboot recovery is done
 521  */
 522 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 523 {
 524         struct nfs_delegation *delegation;
 525         struct inode *inode;
 526 restart:
 527         rcu_read_lock();
 528         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 529                 if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
 530                         continue;
 531                 inode = nfs_delegation_grab_inode(delegation);
 532                 if (inode == NULL)
 533                         continue;
 534                 delegation = nfs_detach_delegation(NFS_I(inode), clp);
 535                 rcu_read_unlock();
 536                 if (delegation != NULL)
 537                         nfs_free_delegation(delegation);
 538                 iput(inode);
 539                 goto restart;
 540         }
 541         rcu_read_unlock();
 542 }
 543
 544 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 545 {
 546         struct nfs_inode *nfsi = NFS_I(inode);
 547         struct nfs_delegation *delegation;
 548         int ret = 0;
 549
 550         rcu_read_lock();
 551         delegation = rcu_dereference(nfsi->delegation);
 552         if (delegation != NULL) {
 553                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 554                 ret = 1;
 555         }
 556         rcu_read_unlock();
 557         return ret;
 558 }