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 *nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 179                                                            const nfs4_stateid *stateid,
 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         spin_lock(&delegation->lock);
 189         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 190                                 sizeof(delegation->stateid.data)) != 0)
 191                 goto nomatch_unlock;
 192         list_del_rcu(&delegation->super_list);
 193         delegation->inode = NULL;
 194         nfsi->delegation_state = 0;
 195         rcu_assign_pointer(nfsi->delegation, NULL);
 196         spin_unlock(&delegation->lock);
 197         return delegation;
 198 nomatch_unlock:
 199         spin_unlock(&delegation->lock);
 200 nomatch:
 201         return NULL;
 202 }
 203
 204 /*
 205  * Set up a delegation on an inode
 206  */
 207 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 208 {
 209         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 210         struct nfs_inode *nfsi = NFS_I(inode);
 211         struct nfs_delegation *delegation, *old_delegation;
 212         struct nfs_delegation *freeme = NULL;
 213         int status = 0;
 214
 215         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 216         if (delegation == NULL)
 217                 return -ENOMEM;
 218         memcpy(delegation->stateid.data, res->delegation.data,
 219                         sizeof(delegation->stateid.data));
 220         delegation->type = res->delegation_type;
 221         delegation->maxsize = res->maxsize;
 222         delegation->change_attr = nfsi->change_attr;
 223         delegation->cred = get_rpccred(cred);
 224         delegation->inode = inode;
 225         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 226         spin_lock_init(&delegation->lock);
 227
 228         spin_lock(&clp->cl_lock);
 229         old_delegation = rcu_dereference_protected(nfsi->delegation,
 230                                                    lockdep_is_held(&clp->cl_lock));
 231         if (old_delegation != NULL) {
 232                 if (memcmp(&delegation->stateid, &old_delegation->stateid,
 233                                         sizeof(old_delegation->stateid)) == 0 &&
 234                                 delegation->type == old_delegation->type) {
 235                         goto out;
 236                 }
 237                 /*
 238                  * Deal with broken servers that hand out two
 239                  * delegations for the same file.
 240                  */
 241                 dfprintk(FILE, "%s: server %s handed out "
 242                                 "a duplicate delegation!\n",
 243                                 __func__, clp->cl_hostname);
 244                 if (delegation->type <= old_delegation->type) {
 245                         freeme = delegation;
 246                         delegation = NULL;
 247                         goto out;
 248                 }
 249                 freeme = nfs_detach_delegation_locked(nfsi, NULL, clp);
 250         }
 251         list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 252         nfsi->delegation_state = delegation->type;
 253         rcu_assign_pointer(nfsi->delegation, delegation);
 254         delegation = NULL;
 255
 256         /* Ensure we revalidate the attributes and page cache! */
 257         spin_lock(&inode->i_lock);
 258         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 259         spin_unlock(&inode->i_lock);
 260
 261 out:
 262         spin_unlock(&clp->cl_lock);
 263         if (delegation != NULL)
 264                 nfs_free_delegation(delegation);
 265         if (freeme != NULL)
 266                 nfs_do_return_delegation(inode, freeme, 0);
 267         return status;
 268 }
 269
 270 /*
 271  * Basic procedure for returning a delegation to the server
 272  */
 273 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 274 {
 275         struct nfs_inode *nfsi = NFS_I(inode);
 276         int err;
 277
 278         /*
 279          * Guard against new delegated open/lock/unlock calls and against
 280          * state recovery
 281          */
 282         down_write(&nfsi->rwsem);
 283         err = nfs_delegation_claim_opens(inode, &delegation->stateid);
 284         up_write(&nfsi->rwsem);
 285         if (err)
 286                 goto out;
 287
 288         err = nfs_do_return_delegation(inode, delegation, issync);
 289 out:
 290         return err;
 291 }
 292
 293 /*
 294  * Return all delegations that have been marked for return
 295  */
 296 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 297 {
 298         struct nfs_delegation *delegation;
 299         struct inode *inode;
 300         int err = 0;
 301
 302 restart:
 303         rcu_read_lock();
 304         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 305                 if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 306                         continue;
 307                 inode = nfs_delegation_grab_inode(delegation);
 308                 if (inode == NULL)
 309                         continue;
 310                 spin_lock(&clp->cl_lock);
 311                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
 312                 spin_unlock(&clp->cl_lock);
 313                 rcu_read_unlock();
 314                 if (delegation != NULL) {
 315                         filemap_flush(inode->i_mapping);
 316                         err = __nfs_inode_return_delegation(inode, delegation, 0);
 317                 }
 318                 iput(inode);
 319                 if (!err)
 320                         goto restart;
 321                 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 322                 return err;
 323         }
 324         rcu_read_unlock();
 325         return 0;
 326 }
 327
 328 /*
 329  * This function returns the delegation without reclaiming opens
 330  * or protecting against delegation reclaims.
 331  * It is therefore really only safe to be called from
 332  * nfs4_clear_inode()
 333  */
 334 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 335 {
 336         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 337         struct nfs_inode *nfsi = NFS_I(inode);
 338         struct nfs_delegation *delegation;
 339
 340         if (rcu_access_pointer(nfsi->delegation) != NULL) {
 341                 spin_lock(&clp->cl_lock);
 342                 delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
 343                 spin_unlock(&clp->cl_lock);
 344                 if (delegation != NULL)
 345                         nfs_do_return_delegation(inode, delegation, 0);
 346         }
 347 }
 348
 349 int nfs_inode_return_delegation(struct inode *inode)
 350 {
 351         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 352         struct nfs_inode *nfsi = NFS_I(inode);
 353         struct nfs_delegation *delegation;
 354         int err = 0;
 355
 356         if (rcu_access_pointer(nfsi->delegation) != NULL) {
 357                 spin_lock(&clp->cl_lock);
 358                 delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
 359                 spin_unlock(&clp->cl_lock);
 360                 if (delegation != NULL) {
 361                         nfs_wb_all(inode);
 362                         err = __nfs_inode_return_delegation(inode, delegation, 1);
 363                 }
 364         }
 365         return err;
 366 }
 367
 368 static void nfs_mark_return_delegation(struct nfs_client *clp, struct nfs_delegation *delegation)
 369 {
 370         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 371         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 372 }
 373
 374 /*
 375  * Return all delegations associated to a super block
 376  */
 377 void nfs_super_return_all_delegations(struct super_block *sb)
 378 {
 379         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 380         struct nfs_delegation *delegation;
 381
 382         if (clp == NULL)
 383                 return;
 384         rcu_read_lock();
 385         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 386                 spin_lock(&delegation->lock);
 387                 if (delegation->inode != NULL && delegation->inode->i_sb == sb)
 388                         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 389                 spin_unlock(&delegation->lock);
 390         }
 391         rcu_read_unlock();
 392         if (nfs_client_return_marked_delegations(clp) != 0)
 393                 nfs4_schedule_state_manager(clp);
 394 }
 395
 396 static
 397 void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp, fmode_t flags)
 398 {
 399         struct nfs_delegation *delegation;
 400
 401         rcu_read_lock();
 402         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 403                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 404                         continue;
 405                 if (delegation->type & flags)
 406                         nfs_mark_return_delegation(clp, delegation);
 407         }
 408         rcu_read_unlock();
 409 }
 410
 411 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 412 {
 413         nfs_client_mark_return_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
 414 }
 415
 416 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 417 {
 418         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 419                 nfs4_schedule_state_manager(clp);
 420 }
 421
 422 void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags)
 423 {
 424         nfs_client_mark_return_all_delegation_types(clp, flags);
 425         nfs_delegation_run_state_manager(clp);
 426 }
 427
 428 void nfs_expire_all_delegations(struct nfs_client *clp)
 429 {
 430         nfs_expire_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
 431 }
 432
 433 /*
 434  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 435  */
 436 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 437 {
 438         if (clp == NULL)
 439                 return;
 440         nfs_client_mark_return_all_delegations(clp);
 441 }
 442
 443 static void nfs_client_mark_return_unreferenced_delegations(struct nfs_client *clp)
 444 {
 445         struct nfs_delegation *delegation;
 446
 447         rcu_read_lock();
 448         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 449                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 450                         continue;
 451                 nfs_mark_return_delegation(clp, delegation);
 452         }
 453         rcu_read_unlock();
 454 }
 455
 456 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 457 {
 458         nfs_client_mark_return_unreferenced_delegations(clp);
 459         nfs_delegation_run_state_manager(clp);
 460 }
 461
 462 /*
 463  * Asynchronous delegation recall!
 464  */
 465 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
 466 {
 467         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 468         struct nfs_delegation *delegation;
 469
 470         rcu_read_lock();
 471         delegation = rcu_dereference(NFS_I(inode)->delegation);
 472
 473         if (!clp->cl_mvops->validate_stateid(delegation, stateid)) {
 474                 rcu_read_unlock();
 475                 return -ENOENT;
 476         }
 477
 478         nfs_mark_return_delegation(clp, delegation);
 479         rcu_read_unlock();
 480         nfs_delegation_run_state_manager(clp);
 481         return 0;
 482 }
 483
 484 /*
 485  * Retrieve the inode associated with a delegation
 486  */
 487 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 488 {
 489         struct nfs_delegation *delegation;
 490         struct inode *res = NULL;
 491         rcu_read_lock();
 492         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 493                 spin_lock(&delegation->lock);
 494                 if (delegation->inode != NULL &&
 495                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 496                         res = igrab(delegation->inode);
 497                 }
 498                 spin_unlock(&delegation->lock);
 499                 if (res != NULL)
 500                         break;
 501         }
 502         rcu_read_unlock();
 503         return res;
 504 }
 505
 506 /*
 507  * Mark all delegations as needing to be reclaimed
 508  */
 509 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 510 {
 511         struct nfs_delegation *delegation;
 512         rcu_read_lock();
 513         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 514                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 515         rcu_read_unlock();
 516 }
 517
 518 /*
 519  * Reap all unclaimed delegations after reboot recovery is done
 520  */
 521 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 522 {
 523         struct nfs_delegation *delegation;
 524         struct inode *inode;
 525 restart:
 526         rcu_read_lock();
 527         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 528                 if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
 529                         continue;
 530                 inode = nfs_delegation_grab_inode(delegation);
 531                 if (inode == NULL)
 532                         continue;
 533                 spin_lock(&clp->cl_lock);
 534                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
 535                 spin_unlock(&clp->cl_lock);
 536                 rcu_read_unlock();
 537                 if (delegation != NULL)
 538                         nfs_free_delegation(delegation);
 539                 iput(inode);
 540                 goto restart;
 541         }
 542         rcu_read_unlock();
 543 }
 544
 545 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 546 {
 547         struct nfs_inode *nfsi = NFS_I(inode);
 548         struct nfs_delegation *delegation;
 549         int ret = 0;
 550
 551         rcu_read_lock();
 552         delegation = rcu_dereference(nfsi->delegation);
 553         if (delegation != NULL) {
 554                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 555                 ret = 1;
 556         }
 557         rcu_read_unlock();
 558         return ret;
 559 }