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_KERNEL);
 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 /* Sync all data to disk upon delegation return */
 272 static void nfs_msync_inode(struct inode *inode)
 273 {
 274         filemap_fdatawrite(inode->i_mapping);
 275         nfs_wb_all(inode);
 276         filemap_fdatawait(inode->i_mapping);
 277 }
 278
 279 /*
 280  * Basic procedure for returning a delegation to the server
 281  */
 282 static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 283 {
 284         struct nfs_inode *nfsi = NFS_I(inode);
 285         int err;
 286
 287         /*
 288          * Guard against new delegated open/lock/unlock calls and against
 289          * state recovery
 290          */
 291         down_write(&nfsi->rwsem);
 292         err = nfs_delegation_claim_opens(inode, &delegation->stateid);
 293         up_write(&nfsi->rwsem);
 294         if (err)
 295                 goto out;
 296
 297         err = nfs_do_return_delegation(inode, delegation, issync);
 298 out:
 299         return err;
 300 }
 301
 302 /*
 303  * Return all delegations that have been marked for return
 304  */
 305 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 306 {
 307         struct nfs_delegation *delegation;
 308         struct inode *inode;
 309         int err = 0;
 310
 311 restart:
 312         rcu_read_lock();
 313         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 314                 if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 315                         continue;
 316                 inode = nfs_delegation_grab_inode(delegation);
 317                 if (inode == NULL)
 318                         continue;
 319                 spin_lock(&clp->cl_lock);
 320                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
 321                 spin_unlock(&clp->cl_lock);
 322                 rcu_read_unlock();
 323                 if (delegation != NULL) {
 324                         filemap_flush(inode->i_mapping);
 325                         err = __nfs_inode_return_delegation(inode, delegation, 0);
 326                 }
 327                 iput(inode);
 328                 if (!err)
 329                         goto restart;
 330                 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 331                 return err;
 332         }
 333         rcu_read_unlock();
 334         return 0;
 335 }
 336
 337 /*
 338  * This function returns the delegation without reclaiming opens
 339  * or protecting against delegation reclaims.
 340  * It is therefore really only safe to be called from
 341  * nfs4_clear_inode()
 342  */
 343 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 344 {
 345         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 346         struct nfs_inode *nfsi = NFS_I(inode);
 347         struct nfs_delegation *delegation;
 348
 349         if (rcu_access_pointer(nfsi->delegation) != NULL) {
 350                 spin_lock(&clp->cl_lock);
 351                 delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
 352                 spin_unlock(&clp->cl_lock);
 353                 if (delegation != NULL)
 354                         nfs_do_return_delegation(inode, delegation, 0);
 355         }
 356 }
 357
 358 int nfs_inode_return_delegation(struct inode *inode)
 359 {
 360         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 361         struct nfs_inode *nfsi = NFS_I(inode);
 362         struct nfs_delegation *delegation;
 363         int err = 0;
 364
 365         if (rcu_access_pointer(nfsi->delegation) != NULL) {
 366                 spin_lock(&clp->cl_lock);
 367                 delegation = nfs_detach_delegation_locked(nfsi, NULL, clp);
 368                 spin_unlock(&clp->cl_lock);
 369                 if (delegation != NULL) {
 370                         nfs_msync_inode(inode);
 371                         err = __nfs_inode_return_delegation(inode, delegation, 1);
 372                 }
 373         }
 374         return err;
 375 }
 376
 377 static void nfs_mark_return_delegation(struct nfs_client *clp, struct nfs_delegation *delegation)
 378 {
 379         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 380         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 381 }
 382
 383 /*
 384  * Return all delegations associated to a super block
 385  */
 386 void nfs_super_return_all_delegations(struct super_block *sb)
 387 {
 388         struct nfs_client *clp = NFS_SB(sb)->nfs_client;
 389         struct nfs_delegation *delegation;
 390
 391         if (clp == NULL)
 392                 return;
 393         rcu_read_lock();
 394         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 395                 spin_lock(&delegation->lock);
 396                 if (delegation->inode != NULL && delegation->inode->i_sb == sb)
 397                         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 398                 spin_unlock(&delegation->lock);
 399         }
 400         rcu_read_unlock();
 401         if (nfs_client_return_marked_delegations(clp) != 0)
 402                 nfs4_schedule_state_manager(clp);
 403 }
 404
 405 static
 406 void nfs_client_mark_return_all_delegation_types(struct nfs_client *clp, fmode_t flags)
 407 {
 408         struct nfs_delegation *delegation;
 409
 410         rcu_read_lock();
 411         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 412                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 413                         continue;
 414                 if (delegation->type & flags)
 415                         nfs_mark_return_delegation(clp, delegation);
 416         }
 417         rcu_read_unlock();
 418 }
 419
 420 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 421 {
 422         nfs_client_mark_return_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
 423 }
 424
 425 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 426 {
 427         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 428                 nfs4_schedule_state_manager(clp);
 429 }
 430
 431 void nfs_expire_all_delegation_types(struct nfs_client *clp, fmode_t flags)
 432 {
 433         nfs_client_mark_return_all_delegation_types(clp, flags);
 434         nfs_delegation_run_state_manager(clp);
 435 }
 436
 437 void nfs_expire_all_delegations(struct nfs_client *clp)
 438 {
 439         nfs_expire_all_delegation_types(clp, FMODE_READ|FMODE_WRITE);
 440 }
 441
 442 /*
 443  * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
 444  */
 445 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 446 {
 447         if (clp == NULL)
 448                 return;
 449         nfs_client_mark_return_all_delegations(clp);
 450 }
 451
 452 static void nfs_client_mark_return_unreferenced_delegations(struct nfs_client *clp)
 453 {
 454         struct nfs_delegation *delegation;
 455
 456         rcu_read_lock();
 457         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 458                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 459                         continue;
 460                 nfs_mark_return_delegation(clp, delegation);
 461         }
 462         rcu_read_unlock();
 463 }
 464
 465 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 466 {
 467         nfs_client_mark_return_unreferenced_delegations(clp);
 468         nfs_delegation_run_state_manager(clp);
 469 }
 470
 471 /*
 472  * Asynchronous delegation recall!
 473  */
 474 int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid,
 475                                       int (*validate_stateid)(struct nfs_delegation *delegation,
 476                                                               const nfs4_stateid *stateid))
 477 {
 478         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 479         struct nfs_delegation *delegation;
 480
 481         rcu_read_lock();
 482         delegation = rcu_dereference(NFS_I(inode)->delegation);
 483
 484         if (!validate_stateid(delegation, stateid)) {
 485                 rcu_read_unlock();
 486                 return -ENOENT;
 487         }
 488
 489         nfs_mark_return_delegation(clp, delegation);
 490         rcu_read_unlock();
 491         nfs_delegation_run_state_manager(clp);
 492         return 0;
 493 }
 494
 495 /*
 496  * Retrieve the inode associated with a delegation
 497  */
 498 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle)
 499 {
 500         struct nfs_delegation *delegation;
 501         struct inode *res = NULL;
 502         rcu_read_lock();
 503         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 504                 spin_lock(&delegation->lock);
 505                 if (delegation->inode != NULL &&
 506                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 507                         res = igrab(delegation->inode);
 508                 }
 509                 spin_unlock(&delegation->lock);
 510                 if (res != NULL)
 511                         break;
 512         }
 513         rcu_read_unlock();
 514         return res;
 515 }
 516
 517 /*
 518  * Mark all delegations as needing to be reclaimed
 519  */
 520 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 521 {
 522         struct nfs_delegation *delegation;
 523         rcu_read_lock();
 524         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 525                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 526         rcu_read_unlock();
 527 }
 528
 529 /*
 530  * Reap all unclaimed delegations after reboot recovery is done
 531  */
 532 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 533 {
 534         struct nfs_delegation *delegation;
 535         struct inode *inode;
 536 restart:
 537         rcu_read_lock();
 538         list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 539                 if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 0)
 540                         continue;
 541                 inode = nfs_delegation_grab_inode(delegation);
 542                 if (inode == NULL)
 543                         continue;
 544                 spin_lock(&clp->cl_lock);
 545                 delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL, clp);
 546                 spin_unlock(&clp->cl_lock);
 547                 rcu_read_unlock();
 548                 if (delegation != NULL)
 549                         nfs_free_delegation(delegation);
 550                 iput(inode);
 551                 goto restart;
 552         }
 553         rcu_read_unlock();
 554 }
 555
 556 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 557 {
 558         struct nfs_inode *nfsi = NFS_I(inode);
 559         struct nfs_delegation *delegation;
 560         int ret = 0;
 561
 562         rcu_read_lock();
 563         delegation = rcu_dereference(nfsi->delegation);
 564         if (delegation != NULL) {
 565                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
 566                 ret = 1;
 567         }
 568         rcu_read_unlock();
 569         return ret;
 570 }