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/smp_lock.h>
  15 #include <linux/spinlock.h>
  16
  17 #include <linux/nfs4.h>
  18 #include <linux/nfs_fs.h>
  19 #include <linux/nfs_xdr.h>
  20
  21 #include "nfs4_fs.h"
  22 #include "delegation.h"
  23 #include "internal.h"
  24
  25 static void nfs_do_free_delegation(struct nfs_delegation *delegation)
  26 {
  27         if (delegation->cred)
  28                 put_rpccred(delegation->cred);
  29         kfree(delegation);
  30 }
  31
  32 static void nfs_free_delegation_callback(struct rcu_head *head)
  33 {
  34         struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
  35
  36         nfs_do_free_delegation(delegation);
  37 }
  38
  39 static void nfs_free_delegation(struct nfs_delegation *delegation)
  40 {
  41         call_rcu(&delegation->rcu, nfs_free_delegation_callback);
  42 }
  43
  44 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  45 {
  46         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  47 }
  48
  49 int nfs_have_delegation(struct inode *inode, fmode_t flags)
  50 {
  51         struct nfs_delegation *delegation;
  52         int ret = 0;
  53
  54         flags &= FMODE_READ|FMODE_WRITE;
  55         rcu_read_lock();
  56         delegation = rcu_dereference(NFS_I(inode)->delegation);
  57         if (delegation != NULL && (delegation->type & flags) == flags) {
  58                 nfs_mark_delegation_referenced(delegation);
  59                 ret = 1;
  60         }
  61         rcu_read_unlock();
  62         return ret;
  63 }
  64
  65 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
  66 {
  67         struct inode *inode = state->inode;
  68         struct file_lock *fl;
  69         int status = 0;
  70
  71         if (inode->i_flock == NULL)
  72                 goto out;
  73
  74         /* Protect inode->i_flock using the BKL */
  75         lock_kernel();
  76         for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
  77                 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
  78                         continue;
  79                 if (nfs_file_open_context(fl->fl_file) != ctx)
  80                         continue;
  81                 unlock_kernel();
  82                 status = nfs4_lock_delegation_recall(state, fl);
  83                 if (status < 0)
  84                         goto out;
  85                 lock_kernel();
  86         }
  87         unlock_kernel();
  88 out:
  89         return status;
  90 }
  91
  92 static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
  93 {
  94         struct nfs_inode *nfsi = NFS_I(inode);
  95         struct nfs_open_context *ctx;
  96         struct nfs4_state *state;
  97         int err;
  98
  99 again:
 100         spin_lock(&inode->i_lock);
 101         list_for_each_entry(ctx, &nfsi->open_files, list) {
 102                 state = ctx->state;
 103                 if (state == NULL)
 104                         continue;
 105                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 106                         continue;
 107                 if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
 108                         continue;
 109                 get_nfs_open_context(ctx);
 110                 spin_unlock(&inode->i_lock);
 111                 err = nfs4_open_delegation_recall(ctx, state, stateid);
 112                 if (err >= 0)
 113                         err = nfs_delegation_claim_locks(ctx, state);
 114                 put_nfs_open_context(ctx);
 115                 if (err != 0)
 116                         return err;
 117                 goto again;
 118         }
 119         spin_unlock(&inode->i_lock);
 120         return 0;
 121 }
 122
 123 /*
 124  * Set up a delegation on an inode
 125  */
 126 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 127 {
 128         struct nfs_delegation *delegation;
 129         struct rpc_cred *oldcred = NULL;
 130
 131         rcu_read_lock();
 132         delegation = rcu_dereference(NFS_I(inode)->delegation);
 133         if (delegation != NULL) {
 134                 spin_lock(&delegation->lock);
 135                 if (delegation->inode != NULL) {
 136                         memcpy(delegation->stateid.data, res->delegation.data,
 137                                sizeof(delegation->stateid.data));
 138                         delegation->type = res->delegation_type;
 139                         delegation->maxsize = res->maxsize;
 140                         oldcred = delegation->cred;
 141                         delegation->cred = get_rpccred(cred);
 142                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 143                                   &delegation->flags);
 144                         NFS_I(inode)->delegation_state = delegation->type;
 145                         spin_unlock(&delegation->lock);
 146                         put_rpccred(oldcred);
 147                         rcu_read_unlock();
 148                 } else {
 149                         /* We appear to have raced with a delegation return. */
 150                         spin_unlock(&delegation->lock);
 151                         rcu_read_unlock();
 152                         nfs_inode_set_delegation(inode, cred, res);
 153                 }
 154         } else {
 155                 rcu_read_unlock();
 156         }
 157 }
 158
 159 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 160 {
 161         int res = 0;
 162
 163         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
 164         nfs_free_delegation(delegation);
 165         return res;
 166 }
 167
 168 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 169 {
 170         struct inode *inode = NULL;
 171
 172         spin_lock(&delegation->lock);
 173         if (delegation->inode != NULL)
 174                 inode = igrab(delegation->inode);
 175         spin_unlock(&delegation->lock);
 176         return inode;
 177 }
 178
 179 static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 180                                                            const nfs4_stateid *stateid,
 181                                                            struct nfs_client *clp)
 182 {
 183         struct nfs_delegation *delegation =
 184                 rcu_dereference_protected(nfsi->delegation,
 185                                           lockdep_is_held(&clp->cl_lock));
 186
 187         if (delegation == NULL)
 188                 goto nomatch;
 189         spin_lock(&delegation->lock);
 190         if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
 191                                 sizeof(delegation->stateid.data)) != 0)
 192                 goto nomatch_unlock;
 193         list_del_rcu(&delegation->super_list);
 194         delegation->inode = NULL;
 195         nfsi->delegation_state = 0;
 196         rcu_assign_pointer(nfsi->delegation, NULL);
 197         spin_unlock(&delegation->lock);
 198         return delegation;
 199 nomatch_unlock:
 200         spin_unlock(&delegation->lock);
 201 nomatch:
 202         return NULL;
 203 }
 204
 205 /*
 206  * Set up a delegation on an inode
 207  */
 208 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 209 {
 210         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 211         struct nfs_inode *nfsi = NFS_I(inode);
 212         struct nfs_delegation *delegation, *old_delegation;
 213         struct nfs_delegation *freeme = NULL;
 214         int status = 0;
 215
 216         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 217         if (delegation == NULL)
 218                 return -ENOMEM;
 219         memcpy(delegation->stateid.data, res->delegation.data,
 220                         sizeof(delegation->stateid.data));
 221         delegation->type = res->delegation_type;
 222         delegation->maxsize = res->maxsize;
 223         delegation->change_attr = nfsi->change_attr;
 224         delegation->cred = get_rpccred(cred);
 225         delegation->inode = inode;
 226         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 227         spin_lock_init(&delegation->lock);
 228
 229         spin_lock(&clp->cl_lock);
 230         old_delegation = rcu_dereference_protected(nfsi->delegation,
 231                                                    lockdep_is_held(&clp->cl_lock));
 232         if (old_delegation != NULL) {
 233                 if (memcmp(&delegation->stateid, &old_delegation->stateid,
 234                                         sizeof(old_delegation->stateid)) == 0 &&
 235                                 delegation->type == old_delegation->type) {
 236                         goto out;
 237                 }
 238                 /*
 239                  * Deal with broken servers that hand out two
 240                  * delegations for the same file.
 241                  */
 242                 dfprintk(FILE, "%s: server %s handed out "
 243                                 "a duplicate delegation!\n",
 244                                 __func__, clp->cl_hostname);
 245                 if (delegation->type <= old_delegation->type) {
 246                         freeme = delegation;
 247                         delegation = NULL;
 248                         goto out;
 249                 }
 250                 freeme = nfs_detach_delegation_locked(nfsi, NULL, clp);
 251         }
 252         list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 253         nfsi->delegation_state = delegation->type;
 254         rcu_assign_pointer(nfsi->delegation, delegation);
 255         delegation = NULL;
 256
 257         /* Ensure we revalidate the attributes and page cache! */
 258         spin_lock(&inode->i_lock);
 259         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 260         spin_unlock(&inode->i_lock);
 261
 262 out:
 263         spin_unlock(&clp->cl_lock);
 264         if (delegation != NULL)
 265                 nfs_free_delegation(delegation);
 266         if (freeme != NULL)
 267                 nfs_do_return_delegation(inode, freeme, 0);
 268         return status;
 269 }
 270
 271 /*
 272  * Basic procedure for returning a delegation to the server
 273  */
 274 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 275 {
 276         struct nfs_inode *nfsi = NFS_I(inode);
 277         int err;
 278
 279         /*
 280          * Guard against new delegated open/lock/unlock calls and against
 281          * state recovery
 282          */
 283         down_write(&nfsi->rwsem);
 284         err = nfs_delegation_claim_opens(inode, &delegation->stateid);
 285         up_write(&nfsi->rwsem);
 286         if (err)
 287                 goto out;
 288
 289         err = nfs_do_return_delegation(inode, delegation, issync);
 290 out:
 291         return err;
 292 }
 293
 294 /*
 295  * Return all delegations that have been marked for return
 296  */
 297 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 298 {
 299         struct nfs_delegation *delegation;
 300         struct inode *inode;
 301         int err = 0;
 302
 303 restart:
 304         rcu_read_lock();
 305         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 306                 if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 307                         continue;
 308                 inode = nfs_delegation_grab_inode(delegation);
 309                 if (inode == NULL)
 310                         continue;
 311                 spin_lock(&clp->cl_lock);
 312                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
 313                 spin_unlock(&clp->cl_lock);
 314                 rcu_read_unlock();
 315                 if (delegation != NULL) {
 316                         filemap_flush(inode->i_mapping);
 317                         err = __nfs_inode_return_delegation(inode, delegation, 0);
 318                 }
 319                 iput(inode);
 320                 if (!err)
 321                         goto restart;
 322                 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 323                 return err;
 324         }
 325         rcu_read_unlock();
 326         return 0;
 327 }
 328
 329 /*
 330  * This function returns the delegation without reclaiming opens
 331  * or protecting against delegation reclaims.
 332  * It is therefore really only safe to be called from
 333  * nfs4_clear_inode()
 334  */
 335 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 336 {
 337         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 338         struct nfs_inode *nfsi = NFS_I(inode);
 339         struct nfs_delegation *delegation;
 340
 341         if (rcu_access_pointer(nfsi->delegation) != NULL) {
 342                 spin_lock(&clp->cl_lock);
 343                 delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
 344                 spin_unlock(&clp->cl_lock);
 345                 if (delegation != NULL)
 346                         nfs_do_return_delegation(inode, delegation, 0);
 347         }
 348 }
 349
 350 int nfs_inode_return_delegation(struct inode *inode)
 351 {
 352         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 353         struct nfs_inode *nfsi = NFS_I(inode);
 354         struct nfs_delegation *delegation;
 355         int err = 0;
 356
 357         if (rcu_access_pointer(nfsi->delegation) != NULL) {
 358                 spin_lock(&clp->cl_lock);
 359                 delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
 360                 spin_unlock(&clp->cl_lock);
 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                 spin_lock(&clp->cl_lock);
 535                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
 536                 spin_unlock(&clp->cl_lock);
 537                 rcu_read_unlock();
 538                 if (delegation != NULL)
 539                         nfs_free_delegation(delegation);
 540                 iput(inode);
 541                 goto restart;
 542         }
 543         rcu_read_unlock();
 544 }
 545
 546 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 547 {
 548         struct nfs_inode *nfsi = NFS_I(inode);
 549         struct nfs_delegation *delegation;
 550         int ret = 0;
 551
 552         rcu_read_lock();
 553         delegation = rcu_dereference(nfsi->delegation);
 554         if (delegation != NULL) {
 555                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 556                 ret = 1;
 557         }
 558         rcu_read_unlock();
 559         return ret;
 560 }